WorldWideScience

Sample records for modeling wood pole

  1. Finite element modeling of small-scale tapered wood-laminated composite poles with biomimicry features

    Science.gov (United States)

    Cheng Piao; Todd F. Shupe; R.C. Tang; Chung Y. Hse

    2008-01-01

    Tapered composite poles with biomimicry features as in bamboo are a new generation of wood laminated composite poles that may some day be considered as an alternative to solid wood poles that are widely used in the transmission and telecommunication fields. Five finite element models were developed with ANSYS to predict and assess the performance of five types of...

  2. Wood pole overhead lines

    CERN Document Server

    Wareing, Brian

    2005-01-01

    This new book concentrates on the mechanical aspects of distribution wood pole lines, including live line working, environmental influences, climate change and international standards. Other topics include statutory requirements, safety, profiling, traditional and probabilistic design, weather loads, bare and covered conductors, different types of overhead systems, conductor choice, construction and maintenance. A section has also been devoted to the topic of lightning, which is one of the major sources of faults on overhead lines. The book focuses on the effects of this problem and the strate

  3. CFD modeling and experimental validation of heat and mass transfer in wood poles subjected to high temperatures: a conjugate approach

    Science.gov (United States)

    Younsi, R.; Kocaefe, D.; Poncsak, S.; Kocaefe, Y.; Gastonguay, L.

    2008-03-01

    In this article, a coupling method is presented in the case of high thermal treatment of a wood pole and a three-dimensional numerical simulation is proposed. The conservation equations for the wood sample are obtained using diffusion equation with variables diffusion coefficients and the incompressible Reynolds averaged Navier Stokes equations have been solved for the flow field. The connection between the two problems is achieved by expressing the continuity of the state variables and their respective fluxes through the interface. Turbulence closure is obtained by the use of the standard k ɛ model with the usual wall function treatment. The model equations are solved numerically by the commercial package ANSYS-CFX10. The wood pole was subjected to high temperature treatment under different operating conditions. The model validation is carried out via a comparison between the predicted values with those obtained experimentally. The comparison of the numerical and experimental results shows good agreement, implying that the proposed numerical algorithm can be used as a useful tool in designing high-temperature wood treatment processes. A parametric study was also carried out to determine the effects of several parameters such as initial moisture content, wood aspect ratio and final gas temperature on temperature and moisture content distributions within the samples during heat treatment.

  4. Fibreglass as an alternative to wood poles : Transmission and distribution poles and crossarms : use of fiber reinforced composite materials for overhead electric utility lines

    Energy Technology Data Exchange (ETDEWEB)

    Wiles, J.R. [Shakespeare Composites and Electronics, Newberry, SC (United States)

    2002-07-01

    For over thirty years, Shakespeare Composites and Electronics has manufactured fiberglass composite lighting and utility poles, as well as being the number one maker of composite crossarms. Composite poles have a few advantages, such as being lightweight, they do no rust, are woodpecker and termite resistant, use no harmful chemicals, and have long life. A chart displaying the comparative pole weights is presented. The key design factors of fiberglass composite utility poles are: pole diameter, fiberglass type and wind angle, layers (thickness) of fiberglass, resin type and formulation, resin mix consistency, cure cycle and maximum curing temperature, and others. Two charts were also displayed presenting 40 feet class 4 pole bending strengths and 40 feet class 2 pole bending strengths. The author indicated that composite poles have a better strength consistency than wood, while being as consistent as steel and prestressed concrete. The design is based on an overload factor of safety of 2.5 for numerous installations. Some of the analytical methods used include mechanical testing, finite element modeling, and thermal analysis. The author describes in detail the concerns associated with attachments. Coating consists of a system of ultra violet blockers in the resin followed by an added resin rich polyester veil outer surface. In addition, there is a proprietary coating process with additional ultra violet blockers. Quality control is effected at the plant. The weathering system lasts 80 years. figs.

  5. Poles of the S-matrix in Woods-Saxon and Salamon-Vertse potentials

    Science.gov (United States)

    Vertse, T.; Lovas, R. G.; Salamon, P.; Rácz, A.

    2012-10-01

    The motions of the l = 0 poles of the S-matrix with varying potential strength is calculated in a cut-off Woods-Saxon (CWS) potential and in the Salamon-Vertse (SV) potential [3]. Both potentials are zero beyond a certain finite distance but the CWS potential has a jump at the cut while the SV potential goes to zero smoothly. The jump of the CWS potential might cause a strange circling of the trajectories at their starting region. This feature does not appear with the SV potential. Starting points of the trajectories depend on the ranges of the potentials. For CWS these points do depend on the unphysical cut-off radius. In this respect the SV potential seems to be superior to the CWS potential.

  6. Mathematical modelling of wood and briquettes torrefaction

    Energy Technology Data Exchange (ETDEWEB)

    Felfli, Felix Fonseca; Luengo, Carlos Alberto [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Inst. de Fisica Gleb Wataghin. Grupo Combustiveis Alternativos; Soler, Pedro Beaton [Universidad de Oriente, Santiago de Cuba (Cuba). Fac. de Ingenieria Mecanica. Centro de Estudios de Eficiencia Energetica; Rocha, Jose Dilcio [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Nucleo Interdisciplinar de Planejamento Energetico (NIPE)

    2004-07-01

    A mathematical model valid for the torrefaction of wood logs and biomass briquettes is presented. The model described both chemical and physical processes, which take place in a moist piece of wood heated at temperatures between 503 and 573 K. Calibration measurements of the temperature profile and mass loss, were performed on dry cylinders of wood samples during torrefaction in an inert atmosphere at 503, 533, and 553 K. The calculated data shows a good agreement with experiments. The model can be a useful tool to estimate projecting and operating parameters for torrefaction furnaces such as minimum time of torrefaction, energy consumption and the mass yield. (author)

  7. Model for Formation of Dunes at the North Martian Pole

    Institute of Scientific and Technical Information of China (English)

    ZHU Jie; CHEN Chu-Xin

    2010-01-01

    @@ The Mars Global Surveyor Mars Orbiter Camera(MOC)took images of a series of strange horseshoe-shaped dunes at the North Martian pole in 2004.These dunes would be formed due to the strong Martian winds whose pattern is different from that on the Earth.We study the cause of the formation of these dunes and make a model for them.In this model,wind speed near the north Martian pole can be evaluated based on the shape of the dunes.We also estimate the surpassing speed of dunes of different sizes.

  8. Simple Regge pole model for Compton scattering of protons

    Energy Technology Data Exchange (ETDEWEB)

    Saleem, M.; Fazal-e-Aleem

    1978-08-01

    It is shown that by a phenomenological choice of the residue functions, the differential cross section for ..gamma.. p ..-->.. ..gamma.. p, including the very recent measurements up to /sup -/t=4.3 (GeV/c)/sup 2/, can be explained at all measured energies greater than 2 GeV with simple Regge pole model.

  9. Sequential pole dominance model and decay of new mesons

    CERN Document Server

    Chaichian, Masud

    1976-01-01

    The sequential pole dominance model recently proposed by Freund and Nambu (1975) allows predictions to be made about the decay processes which violate the Zweig-Iizuka rule. Detailed comparison of the model with recent experimental data on the decay modes of psi (3095) and psi '(3684) reveals some quantitative disagreement. A possible decay mechanism which can account for this discrepancy is discussed. (7 refs).

  10. Modelling piloted ignition of wood and plastics

    NARCIS (Netherlands)

    Blijderveen, M. van; Bramer, E.A.; Brem, G.

    2012-01-01

    To gain insight in the startup of an incinerator, this article deals with piloted ignition. A newly developed model is described to predict the piloted ignition times of wood, PMMA and PVC. The model is based on the lower flammability limit and the adiabatic flame temperature at this limit. The inco

  11. Micromechanical modelling of mechanical behaviour and strength of wood

    DEFF Research Database (Denmark)

    Mishnaevsky, Leon; Qing, Hai

    2008-01-01

    An overview of the micromechanical theoretical and numerical models of wood is presented. Different methods of analysis of the effects of wood microstructures at different scale levels on the mechanical behaviour, deformation and strength of wood are discussed and compared. Micromechanical models...

  12. Refined Rotational Period, Pole Solution & Shape Model for (3200) Phaethon

    CERN Document Server

    Ansdell, Megan; Hainaut, Olivier; Buie, Marc W; Kaluna, Heather; Bauer, James; Dundon, Luke

    2014-01-01

    (3200) Phaethon exhibits both comet- and asteroid-like properties, suggesting it could be a rare transitional object such as a dormant comet or previously volatile-rich asteroid. This justifies detailed study of (3200) Phaethon's physical properties, as a better understanding of asteroid-comet transition objects can provide insight into minor body evolution. We therefore acquired time-series photometry of (3200) Phaethon over 15 nights from 1994 to 2013, primarily using the Tektronix 2048x2048 pixel CCD on the University of Hawaii 2.2-m telescope. We utilized light curve inversion to: (1) refine (3200) Phaethon's rotational period to P=3.6032+/-0.0008 h; (2) estimate a rotational pole orientation of lambda=+85+/-13 degrees and beta=-20+/-10 degrees; and (3) derive a shape model. We also used our extensive light curve dataset to estimate the slope parameter of (3200) Phaethon's phase curve as G~0.06, consistent with C-type asteroids. We discuss how this highly oblique pole orientation with a negative ecliptic ...

  13. Remarks on orthotropic elastic models applied to wood

    Directory of Open Access Journals (Sweden)

    Nilson Tadeu Mascia

    2006-09-01

    Full Text Available Wood is generally considered an anisotropic material. In terms of engineering elastic models, wood is usually treated as an orthotropic material. This paper presents an analysis of two principal anisotropic elastic models that are usually applied to wood. The first one, the linear orthotropic model, where the material axes L (Longitudinal, R( radial and T(tangential are coincident with the Cartesian axes (x, y, z, is more accepted as wood elastic model. The other one, the cylindrical orthotropic model is more adequate of the growth caracteristics of wood but more mathematically complex to be adopted in practical terms. Specifically due to its importance in wood elastic parameters, this paper deals with the fiber orientation influence in these models through adequate transformation of coordinates. As a final result, some examples of the linear model, which show the variation of elastic moduli, i.e., Young´s modulus and shear modulus, with fiber orientation are presented.

  14. 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...

  15. Least 1-Norm Pole-Zero Modeling with Sparse Deconvolution for Speech Analysis

    DEFF Research Database (Denmark)

    Shi, Liming; Jensen, Jesper Rindom; Christensen, Mads Græsbøll

    2017-01-01

    . Moreover, to consider the spiky excitation form of the pulse train during voiced speech, the modeling parame- ters and sparse residuals are estimated in an iterative fashion using a least 1-norm pole-zero with sparse deconvolution algorithm. Com- pared with the conventional two-stage least squares pole...

  16. USEPA SHEDS MODEL: METHODOLOGY FOR EXPOSURE ASSESSMENT FOR WOOD PRESERVATIVES

    Science.gov (United States)

    A physically-based, Monte Carlo probabilistic model (SHEDS-Wood: Stochastic Human Exposure and Dose Simulation model for wood preservatives) has been applied to assess the exposure and dose of children to arsenic (As) and chromium (Cr) from contact with chromated copper arsenat...

  17. Pyrolysis of thermally thick wood particles - experiments and mathematical modelling

    Energy Technology Data Exchange (ETDEWEB)

    Moeller Andersen, S.; Thaaning Pedersen, S.; Goebel, B.; Houbak, N.; Henriksen, Ulrik [MEK - DTU, Kgs. Lyngby (Denmark); Dall Bentzen, J. [COWI a/s, Kgs. Lyngby (Denmark)

    2005-07-01

    A simple, dynamic, l-dimensional model describing heating, drying and pyrolysis of thermally thick wood particles with a l-dimensional geometry has been developed and implemented. The model output is the dynamic evolution of both the char yield and the amount of volatiles. The model is developed in such a simple and accessible way, that it easily can be implemented in a larger model for dimensioning and optimisation of applications where pyrolysis is a part of the overall process as for instance gasification. Experiments using a Thermo Gravimetric Analyser (TGA), built so pieces of wood can be fed into a hot atmosphere instantaneously, have been used to observe the influence of various parameters like temperature and size and wood types on the pyrolysis process. Results from the model have been compared with results from the experiments. The comparison showed good accordance when both wood particles with a well-defined geometry (a cylinder) and when beds of wood chips and wood pellets, respectively, were pyrolyzed. The model has proven that transport of heat to the wood; internal transport and accumulation of heat inside the wood and kinetics of pyrolysis are all important parameters. (au)

  18. Modelling piloted ignition of wood and plastics.

    Science.gov (United States)

    van Blijderveen, Maarten; Bramer, Eddy A; Brem, Gerrit

    2012-09-01

    To gain insight in the startup of an incinerator, this article deals with piloted ignition. A newly developed model is described to predict the piloted ignition times of wood, PMMA and PVC. The model is based on the lower flammability limit and the adiabatic flame temperature at this limit. The incoming radiative heat flux, sample thickness and moisture content are some of the used variables. Not only the ignition time can be calculated with the model, but also the mass flux and surface temperature at ignition. The ignition times for softwoods and PMMA are mainly under-predicted. For hardwoods and PVC the predicted ignition times agree well with experimental results. Due to a significant scatter in the experimental data the mass flux and surface temperature calculated with the model are hard to validate. The model is applied on the startup of a municipal waste incineration plant. For this process a maximum allowable primary air flow is derived. When the primary air flow is above this maximum air flow, no ignition can be obtained.

  19. Wood

    DEFF Research Database (Denmark)

    Unterrainer, Walter

    2014-01-01

    has shrinked by 30% since the preindustrial times and in countries like China (with a historic tradition for wooden architecture) we could observe enormous desertification. What does this mean for the use of wood in modern architecture ? A critical reflection is needed. In too many cases...

  20. Wood

    Science.gov (United States)

    David W. Green; Robert H. White; Antoni TenWolde; William Simpson; Joseph Murphy; Robert J. Ross; Roland Hernandez; Stan T. Lebow

    2006-01-01

    Wood is a naturally formed organic material consisting essentially of elongated tubular elements called cells arranged in a parallel manner for the most part. These cells vary in dimensions and wall thickness with position in the tree, age, conditions of growth, and kind of tree. The walls of the cells are formed principally of chain molecules of cellulose, polymerized...

  1. 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...

  2. Traditions connected with the pole shift model of the Pleistocene

    CERN Document Server

    Woelfli, Willy

    2010-01-01

    As is well known, during the Last Glacial Maximum, about 20'000 years ago, the ice was asymmetrically distributed around the present North Pole. It reached the region of New York, while east Siberia remained ice free. Mammoths lived in arctic regions of east Siberia, where now their food cannot grow. Therefore the globe must have been turned in such a way that the North Pole was in Greenland. The required rapid geographic pole shift at the end of the ice ages has been shown to be physically possible, on condition that an astronomical object of planetary size in an extremely eccentric orbit existed. In this postulated situation it was red hot and a disk shaped gas cloud reduced the solar radiation on Earth in a time dependent way. A frequent objection to this hypothesis is that the phenomena should be reported in old traditions. This paper quotes such traditions from passages of Platon, Herodotus, Ovid, papyrus Ipuwer, Gilgamesh, the Bible, American Indians and other civilizations. Far from being exhaustive th...

  3. New Early Paleozoic Paleomagnetic Poles From NW Argentina: a Reappraisal of Tectonic Models

    Science.gov (United States)

    Spagnuolo, C. M.; Rapalini, A. E.; Astini, R. A.

    2007-05-01

    A paleomagnetic study carried out on Early Ordovician volcanic units in the Famatina Ranges of NW Argentina yielded a pre-tectonic paleomagnetic pole at 32.7°S, 4.3°E, (5.6°/ 8.6°, N=14 sites) that is consistent with four previous Early Ordovician poles from the Famatina - Eastern Puna Eruptive Belt of NW Argentina. However, these five poles are rotated around 50° clockwise respect to the coeval reference pole of Gondwana. Our new results seem to confirm previous models of this belt as a paraauthocthonous rotated terrane on the southwestern margin of Gondwana. However, a recent paleomagnetic pole from the Late Cambrian Mesón Group, at the Eastern Cordillera of NW Argentina, corresponding to the Gondwana foreland (4.5°S, 359.0°E, dp=5.5°, dm=8.8°, n=26 samples) and preliminary paleopoles obtained from the same unit and the latest Cambrian - Early Ordovician Santa Victoria Group at other three localities in the same region, also indicate an anomalous pole position rotated some 40° clockwise respect to the reference pole for Gondwana. These results suggest that the postulated model of a rotated terrane for the Famatina-Eastern Puna belt must be reconsidered. Different alternative scenarios including the possibility of an Early Paleozoic displacement of the whole basement of the Eastern Sierras Pampeanas of Argentina ("Pampia") will be explored.

  4. Above-Threshold Poles in Model-Independent Form Factor Parametrizations

    CERN Document Server

    Grinstein, Benjamin

    2015-01-01

    The model-independent parametrization for exclusive hadronic form factors commonly used for semileptonic decays is generalized to allow for the inclusion of above-threshold resonant poles of known mass and width. We discuss the interpretation of such poles, particularly with respect to the analytic structure of the relevant two-point Green's function in which they reside. Their presence has a remarkably small effect on the parametrization, as we show explicitly for the case of $D \\to \\pi e^+ \

  5. Aroma compound sorption by oak wood in a model wine.

    Science.gov (United States)

    Ramirez Ramirez, G; Lubbers, S; Charpentier, C; Feuillat, M; Voilley, A; Chassagne, D

    2001-08-01

    Oak wood used for wine barrels was immersed into a model wine containing eight aroma compounds (e.g., aromatic and terpene alcohols, ethyl esters, and aldehyde), for which activity coefficients in water and model wine were determined using the mutual solubility measurement. A mass balance of these volatiles considering their reactivity in model wine was established. For most of the studied aroma compounds, and mainly for linalool and ethyl octanoate, a sorption behavior into wood was reported for the first time. This phenomenon was selective and could not be related to the solubilities in model wine and hydrophobicities of the studied aroma compounds, suggesting that acid-base and polar characteristics of wood were more involved in this sorption mechanism. This study has also shown that the level of sorption is a function of the ratio of wood surface area/solution volume.

  6. Using airborne HIAPER Pole-to-Pole Observations (HIPPO) to evaluate model and remote sensing estimates of atmospheric carbon dioxide

    Science.gov (United States)

    Frankenberg, Christian; Kulawik, Susan S.; Wofsy, Steven C.; Chevallier, Frédéric; Daube, Bruce; Kort, Eric A.; O'Dell, Christopher; Olsen, Edward T.; Osterman, Gregory

    2016-06-01

    In recent years, space-borne observations of atmospheric carbon dioxide (CO2) have been increasingly used in global carbon-cycle studies. In order to obtain added value from space-borne measurements, they have to suffice stringent accuracy and precision requirements, with the latter being less crucial as it can be reduced by just enhanced sample size. Validation of CO2 column-averaged dry air mole fractions (XCO2) heavily relies on measurements of the Total Carbon Column Observing Network (TCCON). Owing to the sparseness of the network and the requirements imposed on space-based measurements, independent additional validation is highly valuable. Here, we use observations from the High-Performance Instrumented Airborne Platform for Environmental Research (HIAPER) Pole-to-Pole Observations (HIPPO) flights from 01/2009 through 09/2011 to validate CO2 measurements from satellites (Greenhouse Gases Observing Satellite - GOSAT, Thermal Emission Sounder - TES, Atmospheric Infrared Sounder - AIRS) and atmospheric inversion models (CarbonTracker CT2013B, Monitoring Atmospheric Composition and Climate (MACC) v13r1). We find that the atmospheric models capture the XCO2 variability observed in HIPPO flights very well, with correlation coefficients (r2) of 0.93 and 0.95 for CT2013B and MACC, respectively. Some larger discrepancies can be observed in profile comparisons at higher latitudes, in particular at 300 hPa during the peaks of either carbon uptake or release. These deviations can be up to 4 ppm and hint at misrepresentation of vertical transport. Comparisons with the GOSAT satellite are of comparable quality, with an r2 of 0.85, a mean bias μ of -0.06 ppm, and a standard deviation σ of 0.45 ppm. TES exhibits an r2 of 0.75, μ of 0.34 ppm, and σ of 1.13 ppm. For AIRS, we find an r2 of 0.37, μ of 1.11 ppm, and σ of 1.46 ppm, with latitude-dependent biases. For these comparisons at least 6, 20, and 50 atmospheric soundings have been averaged for GOSAT, TES, and AIRS

  7. Modelling inorganic biocide emission from treated wood in water

    Energy Technology Data Exchange (ETDEWEB)

    Tiruta-Barna, Ligia, E-mail: Ligia.barna@insa-toulouse.fr [Universite de Toulouse, INSA, UPS, INP, LISBP, 135 Avenue de Rangueil, F-31077 Toulouse (France); INRA, UMR792, Laboratoire d' Ingenierie des Systemes Biologiques et des Procedes, F-31400 Toulouse (France); CNRS, UMR5504, F-31400 Toulouse (France); Schiopu, Nicoleta [Universite Paris-Est, CSTB- Scientific and Technical Centre for the Building Industry, ESE/Environment, 24, rue Joseph Fourier, 38400 Saint Martin d' Heres (France)

    2011-09-15

    Highlights: {center_dot} We developed a mechanistic model for biocide metals fixation/mobilisation in wood. {center_dot} This is the first chemical model explaining the biocide leaching from treated wood. {center_dot} The main fixation mechanism is the surface complexation with wood polymers. {center_dot} The biocide mobilization is due to metal-DOC complexation and pH effect. - Abstract: The objective of this work is to develop a chemical model for explaining the leaching behaviour of inorganic biocides from treated wood. The standard leaching test XP CEN/TS14429 was applied to a commercial construction material made of treated Pinus sylvestris (Copper Boron Azole preservative). The experimental results were used for developing a chemical model under PHREEQC (a geochemical software, with LLNL, MINTEQ data bases) by considering the released species detected in the eluates: main biocides Cu and B, other trace biocides (Cr and Zn), other elements like Ca, K, Cl, SO{sub 4}{sup -2}, dissolved organic matter (DOC). The model is based on chemical phenomena at liquid/solid interfaces (complexation, ion exchange and hydrolysis) and is satisfactory for the leaching behaviour representation. The simulation results confronted with the experiments confirmed the hypotheses of: (1) biocide fixation by surface complexation reactions with wood specific sites (carboxyl and phenol for Cu, Zn, Cr(III), aliphatic hydroxyl for B, ion exchange to a lesser extent) and (2) biocide mobilisation by extractives (DOC) coming from the wood. The maximum of Cu, Cr(III) and Zn fixation occurred at neutral pH (including the natural pH of wood), while B fixation was favoured at alkaline pH.

  8. Wettability of Sanded and Aged Fast-growing Poplar Wood Surfaces: II. Dynamic Wetting Models

    OpenAIRE

    Zhiyong Qin; Qian Zhang; Qiang Gao; Shifeng Zhang; Jianzhang Li

    2014-01-01

    The dynamic wettability of adhesive on sanded and aged wood surfaces was measured using the sessile drop method. Four different models were used to evaluate and compare the wetting process. It was shown that the wettability of freshly sanded wood and aged wood both decreased compared to the control wood. There was no evidence of change in wettability with increasing grit number. Aging reduced the wettability of the wood surface. The coefficients of determination (R2) for all four models were ...

  9. A Model For Non-Fickian Moisture Transfer In Wood

    DEFF Research Database (Denmark)

    Krabbenhøft, Kristian; Damkilde, Lars

    2004-01-01

    A model for non-Fickian moisture transfer in wood is presented. The model considers the transfer of water vapour separate from the transfer of bound water. These two components are linked by an equation describing the sorption on the cell wall level. Hereby, a formulation capable of describing...

  10. A Model For Non-Fickian Moisture Transfer In Wood

    DEFF Research Database (Denmark)

    Krabbenhøft, Kristian; Damkilde, Lars

    2004-01-01

    A model for non-Fickian moisture transfer in wood is presented. The model considers the transfer of water vapour separate from the transfer of bound water. These two components are linked by an equation describing the sorption on the cell wall level. Hereby, a formulation capable of describing kn...

  11. The impact of celestial pole offset modelling on VLBI UT1 Intensive results

    CERN Document Server

    Malkin, Zinovy

    2011-01-01

    Very Long Baseline Interferometry (VLBI) Intensive sessions are scheduled to provide operational Universal Time (UT1) determinations with low latency. UT1 estimates obtained from these observations heavily depend on the model of the celestial pole motion used during data processing. However, even the most accurate precession-nutation model, IAU 2000/2006, is not accurate enough to realize the full potential of VLBI observations. To achieve the highest possible accuracy in UT1 estimates, a celestial pole offset (CPO), which is the difference between the actual and modelled precession-nutation angles, should be applied. Three CPO models are currently available for users. In this paper, these models have been tested and the differences between UT1 estimates obtained with those models are investigated. It has been shown that neglecting CPO modelling during VLBI UT1 Intensive processing causes systematic errors in UT1 series of up to 20 microarcseconds. It has been also found that using different CPO models causes...

  12. The statistical model for the secondary quick reversals during the geomagnetic pole transition

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A statistical model for the quick reversals during a geomagnetic pole transition is put forward by combining the modern geomagnetic field and paleomagnetic field. The decrease of geomagnetic intensity determines the reversals, and the quick reversals are possibly caused by the interaction between g01 and the other geomagnetic components.

  13. The statistical model for the secondary quick reversals during the geomagnetic pole transition

    Institute of Scientific and Technical Information of China (English)

    刘青松; 朱日祥; 潘永信; 郭斌

    2000-01-01

    A statistical model for the quick reversals during a geomagnetic pole transition is put forward by combining the modern geomagnetic field and paleomagnetic field. The decrease of geomagnetic intensity determines the reversals, and the quick reversals are possibly caused by the interaction between g10 and the other geomagnetic components.

  14. Simple Regge pole model for proton-proton elastic scattering at high energies

    Energy Technology Data Exchange (ETDEWEB)

    Saleem, M.; Fazal-e-Aleem

    1979-06-01

    It is shown that by a phenomemological choice of residue functions, the angular distribution in pp elastic scattering at high energies, including the most recent measurement at ..sqrt..s = 27.4 GeV with squared 4-momentum transfer, -t, extending up to 14 (GeV/c)/sup 2/, can be explained with simple Regge pole model.

  15. Pole tide Love number - an important parameter for polar motion modeling

    Science.gov (United States)

    Kirschner, S.; Schmidt, M. G.; Seitz, F.

    2013-12-01

    The Euler-Liouville equation is the basic physical model to describe Earth rotation. It is based on the balance of angular momentum in the Earth system. The pole tide Love number is needed to characterize the rotational deformation effect, which depends on the internal structure and rheology of the Earth. There is a direct dependency between the pole tide Love number and the period and damping of the Chandler oscillation. Here we estimate the pole tide Love number on the basis of an inversion of the Euler-Liouville equation. The Earth orientation parameters are used as input parameters. They have been observed precisely over several decades by geodetic methods (C01 and C04 time series). It will be shown that the estimated pole tide Love number leads to significantly better results for polar motion compared to the original value taken from the Conventions of the International Earth Rotation and Reference System Service (IERS). Nevertheless the estimation is dependent on the input models for the subsystems (e.g. atmosphere and ocean models), applied estimation approach and time frame. These aspects are analyzed and discussed in detail.

  16. Modelling inorganic biocide emission from treated wood in water.

    Science.gov (United States)

    Tiruta-Barna, Ligia; Schiopu, Nicoleta

    2011-09-15

    The objective of this work is to develop a chemical model for explaining the leaching behaviour of inorganic biocides from treated wood. The standard leaching test XP CEN/TS14429 was applied to a commercial construction material made of treated Pinus sylvestris (Copper Boron Azole preservative). The experimental results were used for developing a chemical model under PHREEQC(®) (a geochemical software, with LLNL, MINTEQ data bases) by considering the released species detected in the eluates: main biocides Cu and B, other trace biocides (Cr and Zn), other elements like Ca, K, Cl, SO(4)(-2), dissolved organic matter (DOC). The model is based on chemical phenomena at liquid/solid interfaces (complexation, ion exchange and hydrolysis) and is satisfactory for the leaching behaviour representation. The simulation results confronted with the experiments confirmed the hypotheses of: (1) biocide fixation by surface complexation reactions with wood specific sites (carboxyl and phenol for Cu, Zn, Cr(III), aliphatic hydroxyl for B, ion exchange to a lesser extent) and (2) biocide mobilisation by extractives (DOC) coming from the wood. The maximum of Cu, Cr(III) and Zn fixation occurred at neutral pH (including the natural pH of wood), while B fixation was favoured at alkaline pH.

  17. Resonance poles and threshold energies for hadron physical problems by a model-independent universal algorithm

    CERN Document Server

    Tripolt, Ralf-Arno; Wambach, Jochen; Moiseyev, Nimrod

    2016-01-01

    We show how complex resonance poles and threshold energies for systems in hadron physics can be accurately obtained by using a method based on the Pad\\'{e}-approximant which was recently developed for the calculation of resonance poles for atomic and molecular auto-ionization systems. The main advantage of this method is the ability to calculate the resonance poles and threshold energies from \\emph{real} spectral data. In order to demonstrate the capabilities of this method we apply it here to an analytical model as well as to experimental data for the squared modulus of the vector pion form factor, the S0 partial wave amplitude for $\\pi\\pi$ scattering and the cross section ratio $R(s)$ for $e^+e^-$ collisions. The extracted values for the resonance poles of the $\\rho(770)$ and the $f_0(500)$ or $\\sigma$ meson are in very good agreement with the literature. When the data are noisy the prediction of decay thresholds proves to be less accurate but feasible.

  18. Wood Pyrolysis Using Aspen Plus Simulation and Industrially Applicable Model

    Directory of Open Access Journals (Sweden)

    Lestinsky Pavel

    2016-03-01

    Full Text Available Over the past decades, a great deal of experimental work has been carried out on the development of pyrolysis processes for wood and waste materials. Pyrolysis is an important phenomenon in thermal treatment of wood, therefore, the successful modelling of pyrolysis to predict the rate of volatile evolution is also of great importance. Pyrolysis experiments of waste spruce sawdust were carried out. During the experiment, gaseous products were analysed to determine a change in the gas composition with increasing temperature. Furthermore, the model of pyrolysis was created using Aspen Plus software. Aspects of pyrolysis are discussed with a description of how various temperatures affect the overall reaction rate and the yield of volatile components. The pyrolysis Aspen plus model was compared with the experimental data. It was discovered that the Aspen Plus model, being used by several authors, is not good enough for pyrolysis process description, but it can be used for gasification modelling.

  19. A genetic algorithm for optimizing multi-pole Debye models of tissue dielectric properties

    Science.gov (United States)

    Clegg, J.; Robinson, M. P.

    2012-10-01

    Models of tissue dielectric properties (permittivity and conductivity) enable the interactions of tissues and electromagnetic fields to be simulated, which has many useful applications in microwave imaging, radio propagation, and non-ionizing radiation dosimetry. Parametric formulae are available, based on a multi-pole model of tissue dispersions, but although they give the dielectric properties over a wide frequency range, they do not convert easily to the time domain. An alternative is the multi-pole Debye model which works well in both time and frequency domains. Genetic algorithms are an evolutionary approach to optimization, and we found that this technique was effective at finding the best values of the multi-Debye parameters. Our genetic algorithm optimized these parameters to fit to either a Cole-Cole model or to measured data, and worked well over wide or narrow frequency ranges. Over 10 Hz-10 GHz the best fits for muscle, fat or bone were each found for ten dispersions or poles in the multi-Debye model. The genetic algorithm is a fast and effective method of developing tissue models that compares favourably with alternatives such as the rational polynomial fit.

  20. A genetic algorithm for optimizing multi-pole Debye models of tissue dielectric properties.

    Science.gov (United States)

    Clegg, J; Robinson, M P

    2012-10-01

    Models of tissue dielectric properties (permittivity and conductivity) enable the interactions of tissues and electromagnetic fields to be simulated, which has many useful applications in microwave imaging, radio propagation, and non-ionizing radiation dosimetry. Parametric formulae are available, based on a multi-pole model of tissue dispersions, but although they give the dielectric properties over a wide frequency range, they do not convert easily to the time domain. An alternative is the multi-pole Debye model which works well in both time and frequency domains. Genetic algorithms are an evolutionary approach to optimization, and we found that this technique was effective at finding the best values of the multi-Debye parameters. Our genetic algorithm optimized these parameters to fit to either a Cole-Cole model or to measured data, and worked well over wide or narrow frequency ranges. Over 10 Hz-10 GHz the best fits for muscle, fat or bone were each found for ten dispersions or poles in the multi-Debye model. The genetic algorithm is a fast and effective method of developing tissue models that compares favourably with alternatives such as the rational polynomial fit.

  1. Robustness of Control System Tuned by Multiple Dominant Pole Method and Desired Model Method

    Directory of Open Access Journals (Sweden)

    Miloslav SPURNÝ

    2011-06-01

    Full Text Available In the article two analytical analog controller PI tuning methods are shortly described and compared from the point of view of the control system robustness for the first order plus time delay plant. For comparison the multiple dominant pole method and the desired model method were chosen.The program Matlab/Simulink for verification of the control system robustness was used.

  2. Structure-Property Characterization of the Crinkle-Leaf Peach Wood Phenotype: A Future Model System for Wood Properties Research?

    Science.gov (United States)

    Wiedenhoeft, Alex C.; Arévalo, Rafael; Ledbetter, Craig; Jakes, Joseph E.

    2016-09-01

    Nearly 400 million years of evolution and field-testing by the natural world has given humans thousands of wood types, each with unique structure-property relationships to study, exploit, and ideally, to manipulate, but the slow growth of trees makes them a recalcitrant experimental system. Variations in wood features of two genotypes of peach ( Prunus persica L.) trees, wild-type and crinkle-leaf, were examined to elucidate the nature of weak wood in crinkle-leaf trees. Crinkle-leaf is a naturally-occurring mutation in which wood strength is altered in conjunction with an easily observed `crinkling' of the leaves' surface. Trees from three vigor classes (low growth rate, average growth rate, and high growth rate) of each genotype were sampled. No meaningful tendency of dissimilarities among the different vigor classes was found, nor any pattern in features in a genotype-by-vigor analysis. Wild-type trees exhibited longer vessels and fibers, wider rays, and slightly higher specific gravity. Neither cell wall mechanical properties measured with nanoindentation nor cell wall histochemical properties were statistically or observably different between crinkle-leaf and wild-type wood. The crinkle-leaf mutant has the potential to be a useful model system for wood properties investigation and manipulation if it can serve as a field-observable vegetative marker for altered wood properties.

  3. Landau pole in the Standard Model with weakly interacting scalar fields

    Directory of Open Access Journals (Sweden)

    Yuta Hamada

    2015-07-01

    Full Text Available We consider the Standard Model with a new scalar field X which is an nX representation of the SU(2L with a hypercharge YX. The renormalization group running effects on the new scalar quartic coupling constants are evaluated. Even if we set the scalar quartic coupling constants to be zero at the scale of the new scalar field, the coupling constants are induced by the one-loop effect of the weak gauge bosons. Once non-vanishing couplings are generated, the couplings rapidly increase by renormalization group effect of the quartic coupling constant itself. As a result, the Landau pole appears below Planck scale if nX≥4. We find that the scale of the obtained Landau pole is much lower than that evaluated by solving the one-loop beta function of the gauge coupling constants.

  4. Tachyon Pole in σ Meson Propagator in Nuclear Matter in the Relativistic σ-ω Model

    Institute of Scientific and Technical Information of China (English)

    CHEN Wei; AI Bao-Quan; LIU Liang-Gang

    2001-01-01

    The conditions that the tachyon pole of the σ meson propagator in nuclear matter appears are studied in the one-loop approximation in the relativistic σ-ω model. Different from the results of the previous paper, we find that the effect of the constant a in the self-interaction, U(σ) = aσ+ bσ + cσ + dσ , of the σ meson cannot be neglected.It determines the critical density where tachyon appears. The smaller the a, the larger the critical density. The binding energy, pressure, incompressibility coefficient, nucleon effective mass are calculated and the relation between parameters to the tachyon pole is also studied.

  5. Model-independent constraints on hadronic form factors with above-threshold poles

    Science.gov (United States)

    Caprini, Irinel; Grinstein, Benjamín; Lebed, Richard F.

    2017-08-01

    Model-independent constraints on hadronic form factors, in particular those describing exclusive semileptonic decays, can be derived from the knowledge of field correlators calculated in perturbative QCD, using analyticity and unitarity. The location of poles corresponding to below-threshold resonances, i.e., stable states that cannot decay into a pair of hadrons from the crossed channel of the form factor, must be known a priori, and their effect, accounted for through the use of Blaschke factors, is to reduce the strength of the constraints in the semileptonic region. By contrast, above-threshold resonances appear as poles on unphysical Riemann sheets, and their presence does not affect the original model-independent constraints. We discuss the possibility that the above-threshold poles can provide indirect information on the form factors on the first Riemann sheet, either through information from their residues or by constraining the discontinuity function. The bounds on form factors can be improved by imposing, in an exact way, the additional information in the extremal problem. The semileptonic K →π ℓν and D →π ℓν decays are considered as illustrations.

  6. Wood phenology: from organ-scale processes to terrestrial ecosystem models

    Science.gov (United States)

    Delpierre, Nicolas; Guillemot, Joannès

    2016-04-01

    In temperate and boreal trees, a dormancy period prevents organ development during adverse climatic conditions. Whereas the phenology of leaves and flowers has received considerable attention, to date, little is known regarding the phenology of other tree organs such as wood, fine roots, fruits and reserve compounds. In this presentation, we review both the role of environmental drivers in determining the phenology of wood and the models used to predict its phenology in temperate and boreal forest trees. Temperature is a key driver of the resumption of wood activity in spring. There is no such clear dominant environmental cue involved in the cessation of wood formation in autumn, but temperature and water stress appear as prominent factors. We show that wood phenology is a key driver of the interannual variability of wood growth in temperate tree species. Incorporating representations of wood phenology in a terrestrial ecosystem model substantially improved the simulation of wood growth under current climate.

  7. Mathematical modelling of the combustion of a single wood particle

    Energy Technology Data Exchange (ETDEWEB)

    Porteiro, J.; Miguez, J.L.; Granada, E.; Moran, J.C. [Departamento de Ingenieria Mecanica, Maquinas y Motores Termicos y Fluidos. Universidad de Vigo, Lagoas Marcosende 9 36200 Vigo (Spain)

    2006-01-15

    A mathematical model describing the thermal degradation of densified biomass particles is presented here. The model uses a novel discretisation scheme and combines intra-particle combustion processes with extra-particle transport processes, thereby including thermal and diffusional control mechanisms. The influence of structural changes on the physical-thermal properties of wood in its different stages is studied together with shrinkage of the particle during its degradation. The model is used to compare the predicted data with data on the mass loss dynamics and internal temperature of several particles from previous works and relevant literature, with good agreement. (author)

  8. Spatial emission modelling for residential wood combustion in Denmark

    DEFF Research Database (Denmark)

    Plejdrup, Marlene Schmidt; Nielsen, Ole-Kenneth; Brandt, Jørgen

    2016-01-01

    Residential wood combustion (RWC) is a major contributor to atmospheric pollution especially for particulate matter. Air pollution has significant impact on human health, and it is therefore important to know the human exposure. For this purpose, it is necessary with a detailed high resolution...... model with the developed weighting factors (76 ton PM2.5) is in good agreement with the case study (95 ton PM2.5), and that the new model has improved the spatial emission distribution significantly compared to the previous model (284 ton PM2.5). Additionally, a sensitivity analysis was done...

  9. Selected Constitutive Models for Simulating the Hygromechanical Response of Wood

    DEFF Research Database (Denmark)

    Frandsen, Henrik Lund

    -phase transport model. In this paper a so-called multi-Fickian model is revised with respect to the incorporated essential sorption rate model. Based on existing experimental results the sorption rate model is studied. A desorption rate model analogous to the adsorption rate model is proposed. Furthermore......, the boundary conditions are discussed based on discrepancies found for similar research on moisture transport in paper stacks. Paper III: A new sorption hysteresis model suitable for implementation into a numerical method is developed. The prevailing so-called scanning curves are modeled by closed...... in paper III is applied to two different wood species and to bleach-kraft paperboard. Paper V: The sorption hysteresis model is implemented into the multi-Fickian model allowing simultaneous simulation of non-Fickian effects and hysteresis. A key point for this implementation is definition of the condition...

  10. Optimal approximation of head-related transfer function's pole-zero model based on genetic algorithm

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jie; MA Hao; WU Zhen-yang

    2006-01-01

    In the research on spatial hearing and virtual auditory space,it is important to effectively model the head-related transfer functions (HRTFs).Based on the analysis of the HRTFs' spectrum and some perspectives of psychoacoustics,this paper applied multiple demes' parallel and real-valued coding genetic algorithm (GA) to approximate the HRTFs' zero-pole model.Using the logarithmic magnitude's error criterion for the human auditory sense,the results show that the performance of the GA is on the average 39% better than that of the traditional Prony method,and 46% better than that of the Yule-Walker algorithm.

  11. Orientation measurement based on magnetic inductance by the extended distributed multi-pole model.

    Science.gov (United States)

    Wu, Fang; Moon, Seung Ki; Son, Hungsun

    2014-06-27

    This paper presents a novel method to calculate magnetic inductance with a fast-computing magnetic field model referred to as the extended distributed multi-pole (eDMP) model. The concept of mutual inductance has been widely applied for position/orientation tracking systems and applications, yet it is still challenging due to the high demands in robust modeling and efficient computation in real-time applications. Recently, numerical methods have been utilized in design and analysis of magnetic fields, but this often requires heavy computation and its accuracy relies on geometric modeling and meshing that limit its usage. On the other hand, an analytical method provides simple and fast-computing solutions but is also flawed due to its difficulties in handling realistic and complex geometries such as complicated designs and boundary conditions, etc. In this paper, the extended distributed multi-pole model (eDMP) is developed to characterize a time-varying magnetic field based on an existing DMP model analyzing static magnetic fields. The method has been further exploited to compute the mutual inductance between coils at arbitrary locations and orientations. Simulation and experimental results of various configurations of the coils are presented. Comparison with the previously published data shows not only good performance in accuracy, but also effectiveness in computation.

  12. The Landau pole and Z‧ decays in the 331 dilepton model

    Science.gov (United States)

    Martínez, R.; Ochoa, F.

    2007-08-01

    We calculate the decay widths and branching ratios of the extra neutral boson Z’ predicted by the 331 dilepton model in the framework of two different particle contents. These calculations are performed taking into account oblique radiative corrections and flavor changing neutral currents (FCNC) under the ansatz of Matsuda as a texture for the quark mass matrices. Contributions of the order of 10-1-10-2 are obtained in the branching ratios, and the partial widths about one order of magnitude bigger in relation with other 331 models are also obtained. A Landau-like pole arises at 3.5 TeV considering the full particle content of the minimal dilepton model (MDM), where the exotic sector is considered as a degenerate spectrum at the 3 TeV scale. The Landau pole problem can be avoided at the TeV scales if a new leptonic content running below the threshold at 3 TeV is implemented as suggested by other authors.

  13. Equator To Pole in the Cretaceous: A Comparison of Clumped Isotope Data and CESM Model Runs

    Science.gov (United States)

    Petersen, S. V.; Tabor, C. R.; Meyer, K.; Lohmann, K. C.; Poulsen, C. J.; Carpenter, S. J.

    2015-12-01

    An outstanding issue in the field of paleoclimate is the inability of models to reproduce the shallower equator-to-pole temperature gradients suggested by proxies for past greenhouse periods. Here, we focus on the Late Cretaceous (Maastrichtian, 72-66 Ma), when estimated CO2 levels were ~400-1000ppm. New clumped isotope temperature data from more than 10 sites spanning 65°S to 48°N are used to reconstruct the Maastrichtian equator-to-pole temperature gradient. This data is compared to CESM model simulations of the Maastrichtian, run using relevant paleogeography and atmospheric CO2 levels of 560 and 1120 ppm. Due to a reduced "proxy toolkit" this far in the past, much of our knowledge of Cretaceous climate comes from the oxygen isotope paleothermometer, which incorporates an assumption about the oxygen isotopic composition of seawater (δ18Osw), a quantity often related to salinity. With the clumped isotope paleothermometer, we can directly calculate δ18Osw. This will be used to test commonly applied assumptions about water composition, and will be compared to modeled ocean salinity. We also discuss basin-to-basin differences and their implications for paleo-circulation patterns.

  14. Spatial emission modelling for residential wood combustion in Denmark

    DEFF Research Database (Denmark)

    Plejdrup, Marlene Schmidt; Nielsen, Ole-Kenneth; Brandt, Jørgen

    2016-01-01

    Residential wood combustion (RWC) is a major contributor to atmospheric pollution especially for particulate matter. Air pollution has significant impact on human health, and it is therefore important to know the human exposure. For this purpose, it is necessary with a detailed high resolution...... spatial distribution of emissions. In previous studies as well as in the model previously used in Denmark, the spatial resolution is limited, e.g. municipality or county level. Further, in many cases models are mainly relying on population density data as the spatial proxy for distributing the emissions....... This paper describes the new Danish model for high resolution spatial distribution of emissions from RWC to air. The new spatial emission model is based on information regarding building type, and primary and supplementary heating installations from the Danish Building and Dwelling Register (BBR), which...

  15. STOCHASTIC HUMAN EXPOSURE AND DOSE SIMULATION MODEL FOR THE WOOD PRESERVATIVE SCENARIO (SHEDS-WOOD), VERSION 2 MODEL SAS CODE

    Science.gov (United States)

    Concerns have been raised regarding the safety of young children contacting arsenic and chromium residues while playing on and around Chromated Copper Arsenate (CCA) treated wood playground structures and decks. Although CCA registrants voluntarily canceled treated wood for resi...

  16. DecAID: a decaying wood advisory model for Oregon and Washington.

    Science.gov (United States)

    Kim Mellen; Bruce G. Marcot; Janet L. Ohmann; Karen L. Waddell; Elizabeth A. Willhite; Bruce B. Hostetler; Susan A. Livingston; Cay. Ogden

    2002-01-01

    DecAID is a knowledge-based advisory model that provides guidance to managers in determining the size, amount, and distribution of dead and decaying wood (dead and partially dead trees and down wood) necessary to maintain wildlife habitat and ecosystem functions. The intent of the model is to update and replace existing snag-wildlife models in Washington and Oregon....

  17. Refined rotational period, pole solution, and shape model for (3200) Phaethon

    Energy Technology Data Exchange (ETDEWEB)

    Ansdell, Megan; Meech, Karen J.; Kaluna, Heather [NASA Astrobiology Institute, Honolulu, HI 96822 (United States); Hainaut, Olivier [European Southern Observatory, Karl Schwarzschild Straße, 85748 Garching bei München (Germany); Buie, Marc W. [Southwest Research Institute, 1050 Walnut Street, Suite 300, Boulder, CO 80302 (United States); Bauer, James [Jet Propulsion Laboratory, 4800 Oak Grove Drive, MS 183-401, Pasadena, CA 91109 (United States); Dundon, Luke, E-mail: mansdell@ifa.hawaii.edu [United States Navy, Washington, DC 20350 (United States)

    2014-09-20

    (3200) Phaethon exhibits both comet- and asteroid-like properties, suggesting it could be a rare transitional object such as a dormant comet or previously volatile-rich asteroid. This justifies detailed study of (3200) Phaethon's physical properties as a better understanding of asteroid-comet transition objects can provide insight into minor body evolution. We therefore acquired time series photometry of (3200) Phaethon over 15 nights from 1994 to 2013, primarily using the Tektronix 2048 × 2048 pixel CCD on the University of Hawaii 2.2 m telescope. We utilized light curve inversion to (1) refine (3200) Phaethon's rotational period to P = 3.6032 ± 0.0008 hr; (2) estimate a rotational pole orientation of λ = +85° ± 13° and β = –20° ± 10°; and (3) derive a shape model. We also used our extensive light curve data set to estimate the slope parameter of (3200) Phaethon's phase curve as G ∼ 0.06, consistent with C-type asteroids. We discuss how this highly oblique pole orientation with a negative ecliptic latitude supports previous evidence for (3200) Phaethon's origin in the inner main asteroid belt as well as the potential for deeply buried volatiles fueling impulsive yet rare cometary outbursts.

  18. Model for reaction kinetics in pyrolysis of wood

    Energy Technology Data Exchange (ETDEWEB)

    Ahuja, P.; Singh, P.C.; Upadhyay, S.N.; Kumar, S. [Banaras Hindu Univ., Varanasi (India)

    1996-12-31

    A reaction model for the pyrolysis of small and large particles of wood Is developed. The chemical reactions that take place when biomass is pyrolyzed are the devolatilization reactions (primary) and due to the vapour-solid interactions (secondary). In the case of small particles, when the volatiles are immediately removed by the purge gas, only primary reactions occur and the reaction model is described by weight loss and char forming reactions. The of heterogeneous secondary reactions occur in the case of large particles due to the interaction between the volatiles and the hot nascent primary char. A chain reaction mechanism of secondary char formation is proposed. The model takes both the volatiles retention time and cracking and repolymerization reactions of the vapours with the decomposing solid as well as autocatalysis into consideration. 7 refs., 3 figs., 2 tabs.

  19. Model for reaction kinetics in pyrolysis of wood

    Energy Technology Data Exchange (ETDEWEB)

    Ahuja, P.; Singh, P.C.; Upadhyay, S.N.; Kuma, S. [Banaras Hindu Univ., Varanasi (India)

    1996-12-31

    A reaction model for the pyrolysis of small and large particles of wood is developed. The chemical reactions that take place when biomass is pyrolyzed are the devolatilization reactions (primary) and due to the vapour-solid interactions (secondary). In the case of small particles, when the volatiles are immediately removed by the purge gas, only primary reactions occur and the reaction model is described by weight loss and char forming reactions. The heterogeneous secondary reactions occur in the case of large particles due to the interaction between the volatiles and the hot nascent primary char. A chain reaction mechanism of secondary char formation is proposed. The model takes both the volatiles retention time and cracking and repolymerization reactions of the vapours with the decomposing solid as well as autocatalysis into consideration. 6 refs., 3 figs., 2 tabs.

  20. 3D modelling of microscopic structure of ring‑porous wood

    Directory of Open Access Journals (Sweden)

    R. Neugebauer

    2009-01-01

    Full Text Available Nowadays many scientific 3D models of wood are available. These models are suitable only for simulation of physical fields movements in wood but not for educational purposes especially demonstration of microscopic structure of wood.3D structure of ring-porous hardwood species was created. European ash (Faraxinus excelsior L. was selected due to its relatively simple wood structure than other wood species within ring-porous group. The model was created by manual modelling process in Rhinoceros 4.0 that is a software for visualization and modelling. Microslides were prepared from sample of ash to take micro photos that were used as a visual source for modelling. Beside these pictures made by authors of this paper other microphotos from wood anatomy publications were used. Created 3D model of ash is a VRML object (Virtual Reality Modelling Language. This format is available to viewing and presentation with severe freeware VRML browsers. These VRML browsers are available as a plug-in for standard internet browsers or as standalone VRML browsers. The model is useful for studying and teaching microscopic structure of ring‑porous hardwood species. It was created such a way to be as exact copy of original anatomical structure of ash wood as possible. The paper may be used as a cue for other authors to create their own 3D models of different wood kinds.

  1. A 3D multilevel model of damage and strength of wood: Analysis of microstructural effects

    DEFF Research Database (Denmark)

    Qing, Hai; Mishnaevsky, Leon

    2011-01-01

    A 3D hierarchical computational model of damage and strength of wood is developed. The model takes into account the four scale microstructures of wood, including the microfibril reinforced structure at nanoscale, multilayered cell walls at microscale, hexagon-shape-tube cellular structure at meso...

  2. The ARMA model's pole characteristics of Doppler signals from the carotid artery and their classification application

    Institute of Scientific and Technical Information of China (English)

    CHEN Xi; WANG Yuanyuan; ZHANG Yu; WANG Weiqi

    2002-01-01

    In order to diagnose the cerebral infarction, a classification system based onthe ARMA model and BP (Back-Propagation) neural network is presented to analyzeblood flow Doppler signals from the carotid artery. In this system, an ARMA modelis first used to analyze the audio Doppler blood flow signals from the carotid artery.Then several characteristic parameters of the pole's distribution are estimated. Afterstudies of these characteristic parameters' sensitivity to the textcolor cerebral infarctiondiagnosis, a BP neural network using sensitive parameters is established to classify thenormal or abnormal state of the cerebral vessel. With 474 cases used to establish theappropriate neural network, and 52 cases used to test the network, the results showthat the correct classification rate of both training and testing are over 94%. Thus thissystem is useful to diagnose the cerebral infarction.

  3. Modelling and Simulation of Digital Compensation Technique for dc-dc Converter by Pole Placement

    Science.gov (United States)

    Shenbagalakshmi, R.; Sree Renga Raja, T.

    2015-09-01

    A thorough and effective analysis of the dc-dc converters is carried out in order to achieve the system stability and to improve the dynamic performance. A small signal modelling based on state space averaging technique for dc-dc converters is carried out. A digital state feedback gain matrix is derived by pole placement technique in order to achieve the stability of a completely controllable system. A prediction observer for the dc-dc converters is designed and a dynamic compensation (observer plus control law) is provided using separation principle. The output is very much improved with zero output voltage ripples, zero peak overshoot, and much lesser settling time in the range of ms and with higher overall efficiency (>90 %).

  4. Creating competitive poles – the sustainable model for obtaining the competitive advantage

    Directory of Open Access Journals (Sweden)

    Ramona-Mihaela MATEI

    2013-08-01

    Full Text Available In a global economy that has as its own competitive advantage the transfer of information and goods around the world in real time, the annexes that surround the ecosystem are the centers for innovation founded on hedge & mutual funds, investment scenarios and the development of biotechnology (for developed countries or for the development of aircrafts or equipment used for the manufacturing of tangible goods (in emergent countries. For these to create synergy there is the idea of clusters, because they offer to the companies the possibility to change and to add dynamism to the microeconomic open system. Although globalization offers the power of global trading, clusters are found in developed countries with economies that can support multidisciplinary interactions, and their creation must be followed by the emergent countries that want to progress in this area. This paper represents a review and a research in progress on creating competitive poles (or clusters as a sustainable model for obtaining the competitive advantage.

  5. A model of supplying poplar wood for Iranian paper & wood factories

    Institute of Scientific and Technical Information of China (English)

    Majid Azizi

    2008-01-01

    The objective of this research is to design a method for an appropriate alternative to supply poplar wood as raw material for wood and paper factories in Iran.Due to the destruction of the forests and lack of proper plantation,replacement of the forest wood by the fast growing wood is vital to satisfy all requirements of these factories.A hierarchy was used to prioritize benefits,opportunities,costs and risks (BOCR) using the Analytic Hierarchy Process (AHP) ratings approach.To evaluate the "control criteria" of the system,a control hierarchy was also created and prioritized by applying the Analytic Network Process (ANP).A total of four major control criteria in the system are prioritized where each one controls a network structure evaluated by using ANP.The final synthesis results of the system showed that internal poplar tree farming supplied by the forest product factories was the best choice among three potential alternatives (factory procurement,external procurement and mix procurement).

  6. A Phenomenological Thermal-Mechanical Viscoelastic Constitutive Modeling for Polypropylene Wood Composites

    Directory of Open Access Journals (Sweden)

    Xiongqi Peng

    2012-01-01

    Full Text Available This paper presents a phenomenological thermal-mechanical viscoelastic constitutive modeling for polypropylene wood composites. Polypropylene (PP wood composite specimens are compressed at strain rates from 10−4 to 10−2 s−1 and at temperature of , , and , respectively. The mechanical responses are shown to be sensitive both to strain rate and to temperature. Based on the Maxwell viscoelastic model, a nonlinear thermal-mechanical viscoelastic constitutive model is developed for the PP wood composite by decoupling the effect of temperature with that of the strain rate. Corresponding viscoelastic parameters are obtained through curve fitting with experimental data. Then the model is used to simulate thermal compression of the PP wood composite. The predicted theoretical results coincide quite well with experimental data. The proposed constitutive model is then applied to the thermoforming simulation of an automobile interior part with the PP wood composites.

  7. Thermophysical modeling of asteroids from WISE thermal infrared data - Significance of the shape model and the pole orientation uncertainties

    CERN Document Server

    Hanuš, Josef; Ďurech, Josef; Alí-Lagoa, Victor

    2015-01-01

    In the analysis of thermal infrared data of asteroids by means of thermophysical models (TPMs) it is a common practice to neglect the uncertainty of the shape model and the rotational state, which are taken as an input for the model. Here, we present a novel method of investigating the importance of the shape model and the pole orientation uncertainties in the thermophysical modeling - the varied shape TPM (VS-TPM). Our method uses optical photometric data to generate various shape models that map the uncertainty in the shape and the rotational state. The TPM procedure is then run for all these shape models. We apply the implementation of the classical TPM as well as our VS-TPM to the convex shape models of several asteroids together with their thermal infrared data acquired by the NASA's Wide-field Infrared Survey Explorer (WISE) and compare the results. These show that the uncertainties of the shape model and the pole orientation can be very important (e.g., for the determination of the thermal inertia) and...

  8. Spatial emission modelling for residential wood combustion in Denmark

    Science.gov (United States)

    Plejdrup, Marlene S.; Nielsen, Ole-Kenneth; Brandt, Jørgen

    2016-11-01

    Residential wood combustion (RWC) is a major contributor to atmospheric pollution especially for particulate matter. Air pollution has significant impact on human health, and it is therefore important to know the human exposure. For this purpose, it is necessary with a detailed high resolution spatial distribution of emissions. In previous studies as well as in the model previously used in Denmark, the spatial resolution is limited, e.g. municipality or county level. Further, in many cases models are mainly relying on population density data as the spatial proxy for distributing the emissions. This paper describes the new Danish model for high resolution spatial distribution of emissions from RWC to air. The new spatial emission model is based on information regarding building type, and primary and supplementary heating installations from the Danish Building and Dwelling Register (BBR), which holds detailed data for all buildings in Denmark. The new model provides a much more accurate distribution of emissions than the previous model used in Denmark, as the resolution has been increased from municipality level to a 1 km × 1 km resolution, and the distribution key has been significantly improved so that it no longer puts an excessive weight on population density. The new model has been verified for the city of Copenhagen, where emissions estimated using both the previous and the new model have been compared to the emissions estimated in a case study. This comparison shows that the new model with the developed weighting factors (76 ton PM2.5) is in good agreement with the case study (95 ton PM2.5), and that the new model has improved the spatial emission distribution significantly compared to the previous model (284 ton PM2.5). Additionally, a sensitivity analysis was done to illustrate the impact of the weighting factors on the result, showing that the new model independently of the weighting factors chosen produce a more accurate result than the old model.

  9. Pomeron pole plus grey disk model: Real parts, inelastic cross sections and LHC data

    Science.gov (United States)

    Roy, S. M.

    2017-01-01

    I propose a two component analytic formula F (s , t) =F (1) (s , t) +F (2) (s , t) for (ab → ab) + (a b bar → a b bar) scattering at energies ≥ 100 GeV, where s , t denote squares of c.m. energy and momentum transfer. It saturates the Froissart-Martin bound and obeys Auberson-Kinoshita-Martin (AKM) [1,2] scaling. I choose ImF (1) (s , 0) + ImF (2) (s , 0) as given by Particle Data Group (PDG) fits [3,4] to total cross sections, corresponding to simple and triple poles in angular momentum plane. The PDG formula is extended to non-zero momentum transfers using partial waves of ImF (1) and ImF (2) motivated by Pomeron pole and 'grey disk' amplitudes and constrained by inelastic unitarity. ReF (s , t) is deduced from real analyticity: I prove that ReF (s , t) / ImF (s , 0) → (π / ln ⁡ s) d / dτ (τImF (s , t) / ImF (s , 0)) for s → ∞ with τ = t(lns) 2 fixed, and apply it to F (2). Using also the forward slope fit by Schegelsky-Ryskin [5], the model gives real parts, differential cross sections for (- t) 0.5 TeV, with PDG2013 [4] total cross sections, and Schegelsky-Ryskin slopes [5] as input, σinel (s) = 22.6 + . 034 lns + . 158(lns) 2 mb, and σinel /σtot → 0.56, s → ∞, where s is in GeV2 units. Continuation to positive t indicates an 'effective' t-channel singularity at ∼(1.5 GeV) 2, and suggests that usual Froissart-Martin bounds are quantitatively weak as they only assume absence of singularities upto 4 mπ2.

  10. Aerosols at the Poles: An AeroCom Phase II Multi-Model Evaluation

    Science.gov (United States)

    Sand, M.; Samset, B. H.

    2016-12-01

    Atmospheric aerosols from anthropogenic and natural sources reach the Polar Regions through long-range transport. By scattering and absorbing solar radiation, aerosols perturb the energy balance in the region and may have played a significant role in recent Arctic warming. Aerosols in Polar regions are however, poorly constrained in present day global climate models. Here we compare aerosol burdens from simulations with 16 global aerosol models from the Aerocom phase II model inter-comparison project with available observations at both Poles. We show that the annual mean multi-model median Aerosol Optical Depth (AOD) is not a bad representation of the measured AOD in Arctic, even though the model spread is large. The models tend to underestimate the spring maximum and overestimate the summer/autumn minimum. We also document the geographical distribution and seasonal cycle of aerosol burdens and shortwave anthropogenic direct radiative forcing (DRF) of the total aerosol and the individual aerosol species; black carbon (BC), sulfate, and primary organic aerosols from fossil/bio fuel and biomass burning, dust and sea-salt. A subset of models has also reported nitrate and secondary organic aerosols. The models produce an annual mean median AOD 0.07 in the Arctic and 0.01 the Antarctic. The Arctic modeled annual mean DRF is slightly negative -0.12 Wm-2, dominated by a positive black carbon DRF during spring and a negative sulfate DRF during summer. We perform sensitivity experiments with one of the Aerocom models (GISS modelE) to investigate how regional emissions of BC and sulfate and the lifetime of BC influence the Arctic and Antarctic aerosol burdens.

  11. MODELING OF ALKANE EMISSIONS FROM A WOOD STAIN

    Science.gov (United States)

    The article discusses full-scale residential house tests to evaluate the effects of organic emissions from a wood finishing product--wood stain--on indoor air quality (IAQ). The test house concentrations of three alkane species, nonane, decane, and undecane, were measured as a fu...

  12. Experimental analysis and simulation modeling of forest management impacts on wood thrushes, Hylocichla mustelina

    Science.gov (United States)

    Banks, R.C.

    1998-01-01

    North American Breeding Bird Survey data show that wood thrush (Hylocichla mustelina) populations in eastern U.S. forests have declined 1.8% per year during 1966-95. The declining quality of breeding forest tracts in North America is one possible cause for the apparent decline of some neotropical migratory birds, such as the wood thrush. In Georgia, however, wood thrush populations have declined during a period of increasing pine forest area and larger patch sizes. We hypothesized that forest management practices such as thinning and prescribed burning might create unsuitable habitat for wood thrushes. We conducted a four-year before/after, treatment/control experiment at the Piedmont National Wildlife Refuge in central Georgia to study to the effects of a treatment of thinning and prescribed burning on wood thrush demographic parameters. We simultaneously monitored wood thrush adults and juveniles with mark-recapture, radio-telemetry, nest searches, and plot-map surveys. Our analyses showed that wood thrushes were less likely to emigrate from the study compartments after the treatment, and wood thrushes exhibited some tendency to increase preference for hardwood habitats and decrease preference for pine habitats following the treatment. However, we observed no effects of treatment on nest success, adult survival, and adult and juvenile dispersal distances. We also found that female wood thrushes had lower survival rates than males during the breeding season, and we documented large-scale, within-year dispersal movements of adult (up to 17 km) and juvenile (up to 7 km) wood thrushes. We conclude that landscape level habitat quantity and quality must be considered during songbird management decisions. The documentation of sex- and age-specific wood thrush survival and movement rates was critical for construction of a set of population models. We used three stochastic models to learn more about wood thrush population dynamics and make predictions about population

  13. Low-energy effects in a higher-derivative gravity model with real and complex massive poles

    CERN Document Server

    Accioly, Antonio; Shapiro, Ilya L

    2016-01-01

    The most simple super-renormalizable model of quantum gravity is based on the general local covariant six-derivative action. It was recently shown that such a theory may also have unitary S-matrix, in the case when massive poles are complex. In the present work we construct the modified Newton potential and explore the gravitational light bending in a general six-derivative theory, including the most interesting case of complex massive poles. In what concerns light deflection, the results are obtained within classical and semiclassical approaches. The presentation is given in details which can be useful for better understanding the effects of the higher derivative terms.

  14. Fast pyrolysis in a novel wire-mesh reactor: decomposition of pine wood and model compounds

    NARCIS (Netherlands)

    Hoekstra, E.; Swaaij, van W.P.M.; Kersten, S.R.A.; Hogendoorn, J.A.

    2012-01-01

    In fast pyrolysis, biomass decomposition processes are followed by vapor phase reactions. Experimental results were obtained in a unique wire-mesh reactor using pine wood, KCl impregnated pine wood and several model compounds (cellulose, xylan, lignin, levoglucosan, glucose). The wire-mesh reactor w

  15. The molecular architecture of the yeast spindle pole body core determined by Bayesian integrative modeling.

    Science.gov (United States)

    Viswanath, Shruthi; Bonomi, Massimiliano; Kim, Seung Joong; Klenchin, Vadim A; Taylor, Keenan C; Yabut, King C; Umbreit, Neil T; Van Epps, Heather A; Meehl, Janet; Jones, Michele H; Russel, Daniel; Velazquez-Muriel, Javier A; Winey, Mark; Rayment, Ivan; Davis, Trisha N; Sali, Andrej; Muller, Eric G

    2017-08-16

    Microtubule organizing centers (MTOCs) form, anchor and stabilize the polarized network of microtubules in a cell. The central MTOC is the centrosome that duplicates during the cell cycle and during mitosis assembles a bipolar spindle to capture and segregate sister chromatids. Yet, despite their importance in cell biology, the physical structure of MTOCs is poorly understood. Here we determine the molecular architecture of the core of the yeast spindle pole body (SPB) by Bayesian integrative structure modeling based on in vivo FRET, small-angle X-ray scattering (SAXS), X-ray crystallography, electron microscopy and two-hybrid analysis. The model is validated by several methods that include a genetic analysis of the conserved PACT domain that recruits Spc110, a protein related to pericentrin, to the SPB. The model suggests that calmodulin can act as a protein cross-linker and Spc29 is an extended, flexible protein. The model led to the identification of a single, essential heptad in the coiled coil of Spc110 and a minimal PACT domain. It also led to a proposed pathway for the integration of Spc110 into the SPB. © 2017 by The American Society for Cell Biology.

  16. Pole plus cut model and recent polarisation results for the reaction. pi. /sup -/p. -->. pi. /sup 0/n

    Energy Technology Data Exchange (ETDEWEB)

    Fazal-e-Aleem; Saleem, M. (University of the Punjab, Lahore (Pakistan). Centre for High Energy Physics); Rafique, M. (University of the Punjab, Lahore (Pakistan). Dept. of Mathematics)

    1984-10-01

    A pole plus cut model has been used to fit simultaneously the data on dsigma/dt, P(t) and ..delta..sigma for the reaction ..pi../sup -/p ..-->.. ..pi../sup 0/n at high energies; the most recent measurements of polarisation are included in the fit.

  17. 30 CFR 57.6701 - Tamping and loading pole requirements.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Tamping and loading pole requirements. 57.6701 Section 57.6701 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND... poles shall be of wood or other nonconductive, nonsparking material. Couplings for poles shall...

  18. DEVELOPMENT OF NIRS CALIBRATION MODELS FOR MINIMIZATION OF Eucalyptus spp WOOD ANALYSIS

    Directory of Open Access Journals (Sweden)

    Leonardo Chagas de Sousa

    2011-09-01

    Full Text Available The Kennard-Stone algorithm was used to select Eucalyptus spp. wood samples for development of NIRS (Near-Infrared Spectroscopy calibration models aiming to minimize number of samples but maintaining the model precisions. A large number of Eucalyptus spp. wood samples (3369 samples were used to develop NIRS calibration models for the wood basic density, the lignin content and the ethanol-toluene extractives. The models developed with the total number of samples were compared with models developed using only 1000, 500, 200 and 100 samples, which were selected using the Kennard-Stone algorithm. Analysis of the models statistics parameters confirmed the similarity of all models, with exception of the 100 sample models, demonstrating the possibility of substantial savings in time and costs for wood laboratory analysis.  

  19. High-resolution Local Gravity Model of the South Pole of the Moon from GRAIL Extended Mission Data

    Science.gov (United States)

    Goossens, Sander Johannes; Sabaka, Terence J.; Nicholas, Joseph B.; Lemoine, Frank G.; Rowlands, David D.; Mazarico, Erwan; Neumann, Gregory A.; Smith, David E.; Zuber, Maria T.

    2014-01-01

    We estimated a high-resolution local gravity field model over the south pole of the Moon using data from the Gravity Recovery and Interior Laboratory's extended mission. Our solution consists of adjustments with respect to a global model expressed in spherical harmonics. The adjustments are expressed as gridded gravity anomalies with a resolution of 1/6deg by 1/6deg (equivalent to that of a degree and order 1080 model in spherical harmonics), covering a cap over the south pole with a radius of 40deg. The gravity anomalies have been estimated from a short-arc analysis using only Ka-band range-rate (KBRR) data over the area of interest. We apply a neighbor-smoothing constraint to our solution. Our local model removes striping present in the global model; it reduces the misfit to the KBRR data and improves correlations with topography to higher degrees than current global models.

  20. Endogenous learning in world post-Kyoto scenarios: application of the POLES model under adaptive expectations

    Energy Technology Data Exchange (ETDEWEB)

    Kouvaritakis, N.; Soria, A.; Isoard, S. [Commission of the European Communities, Sevilla (Spain). Inst. for Prospective Technological Studies; Thonet, C. [European Commission - Unit DG 12 - Research, Brussels (Belgium)

    2000-07-01

    This paper describes the endogenous technical change module that has been incorporated in POLES and the main quantitative results of the new version of the model and corresponding exercises. Section 2 presents the methodology that has been used in order to assess the returns to R and D for the main power generation technologies identified in the model. R and D budget allocation is then analysed for the base case in Section 3, which also illustrates the differences in the behaviour, respectively of the least and most risk-averse agents. Section 4, analyses in detail the changes in budget allocation that are induced by the introduction of CO{sub 2} emission constraints to 2030, as well as their impacts on marginal and total abatement costs for the main world regions. As a last step, the consequences of changes in public R and D are examined in Section 5. This exercise shows that the performance and diffusion of the technologies benefiting from the shift in public R and D are largely improved, in spite of noticeable 'crowding out' effects - of private research by public research - for these technologies. (orig.)

  1. Comparative environmental assessment of wood transport models: a case study of a Swedish pulp mill.

    Science.gov (United States)

    González-García, Sara; Berg, Staffan; Feijoo, Gumersindo; Moreira, Ma Teresa

    2009-05-15

    Wood transportation from forest landing to forest-based industries uses large amounts of energy. In the case of Sweden, where forest operations are highly and efficiently mechanized, this stage consumes more fossil fuels than other elements of the wood supply chain (such as silviculture and logging operations). This paper intends to compare the environmental burdens associated to different wood transport models considering a Swedish pulp mill as a case study by using Life Cycle Assessment (LCA) as an analytical tool. Five scenarios (the current one and four alternative reliable scenarios) were proposed and analysed taking into account two variables. On the one hand, the influence of imported pulpwood share from Baltic countries and on the other hand, the use of rail transportation for wood transport. In particular, the following impact categories were assessed: Eutrophication, Global Warming, Photochemical Oxidant Formation, Acidification and Fossil fuel extraction. The environmental results indicate that transport alternatives including electric and diesel trains, as well as the reduction in Baltic wood imports should present better environmental performance than the current scenario in terms of all the impact categories under study. Remarkable differences were identified with regard to energy requirements. This divergence is related to different long-distance transport strategies (lorry, boat and/or train) as well as the relative import of wood selected. The combination of lorry and train in wood transportation from Southern Sweden plus the reduction of wood imports from 25% to 15% seems to be more favourable from an environmental perspective. The results obtained allow forecasting the importance of the wood transport strategy in the wood supply chain in LCA of forest products and the influence of energy requirements in the results.

  2. Variational data assimilation problem for the thermodynamics model with displaced pole

    Science.gov (United States)

    Parmuzin, Eugene; Agosgkov, Valery; Zakharova, Natalia

    2017-04-01

    The most versatile and promising technology for solving problems of monitoring and analysis of the natural environment is a four-dimensional variational data assimilation of observation data. The development of computational algorithms for the solution of data assimilation problems in geophysical hydrodynamics is important in the contemporary computation and informational science to improve the quality of long-term prediction by using the hydrodynamics sea model. These problems are applied to close and solve in practice the appropriate inverse problems of the geophysical hydrodynamics. In this work the variational data assimilation problems in the Baltic Sea water area with displaced pole were formulated and studied [1]. We assume, that the unique function which is obtained by observation data processing is the function and we permit that the function is known only on a part of considering area (for example, on a part of the Baltic Sea). Numerical experiments on restoring the ocean heat flux and obtaining solution of the system (temperature, salinity, velocity, and sea surface height) in the Baltic Sea primitive equation hydrodynamics model [2] with assimilation procedure were carried out. In the calculations we used daily sea surface temperature observation from Danish meteorological Institute, prepared on the basis of measurements of the radiometer (AVHRR, AATSR and AMSRE) and spectroradiometer (SEVIRI and MODIS). The spatial resolution of the model grid with respect to the horizontal variables is uniform on latitude (0.2 degree) and varies on longitude from 0.04 to 0.0004 degree . The results of the numerical experiments are presented. This study was supported by the Russian Foundation for Basic Research (project №16-01-00548) and project №14-11-00609 by the Russian Science Foundation. References: [1] Agoshkov V.I., Parmuzin E.I., Zakharova N.B., Zalesny V.B., Shutyaev V.P., Gusev A.V. Variational assimilation of observation data in the mathematical model of

  3. Model prediction for temperature dependence of meson pole masses from lattice QCD results on meson screening masses

    CERN Document Server

    Ishii, Masahiro; Yahiro, Masanobu

    2016-01-01

    We propose a practical effective model by introducing temperature ($T$) dependence to the coupling strengths of four-quark and six-quark Kobayashi-Maskawa-'t Hooft interactions in the 2+1 flavor Polyakov-loop extended Nambu-Jona-Lasinio model. The $T$ dependence is determined from LQCD data on the renormalized chiral condensate around the pseudocritical temperature $T_c^{\\chi}$ of chiral crossover and the screening-mass difference between $\\pi$ and $a_0$ mesons in $T > 1.1T_c^\\chi$ where only the $U(1)_{\\rm A}$-symmetry breaking survives. The model well reproduces LQCD data on screening masses $M_{\\xi}^{\\rm scr}(T)$ for both scalar and pseudoscalar mesons, particularly in $T \\ge T_c^{\\chi}$. Using this effective model, we predict meson pole masses $M_{\\xi}^{\\rm pole}(T)$ for scalar and pseudoscalar mesons. For $\\eta'$ meson, the prediction is consistent with the experimental value at finite $T$ measured in heavy-ion collisions. We point out that the relation $M_{\\xi}^{\\rm scr}(T)-M_{\\xi}^{\\rm pole}(T) \\approx...

  4. Determination of Pole and Rotation Period of not Stabilized Artificial Satellite by Use of Model "diffuse Cylinder"

    Science.gov (United States)

    Kolesnik, S. Ya.; Dobrovolsky, A. V.; Paltsev, N. G.

    The algorithm of determination of orientation of rotation axis (pole) and rotation period of satellite, simulated by a cylinder, which is precessing around of vector of angular moment of pulse with constant nutation angle is offered. The Lambert's law of light reflection is accepted. Simultaneously, dependence of light reflection coefficient versus phase angle is determined. The model's simulation confirm applicability of this method. Results of the calculations for artificial satellite No 28506 are carried out.

  5. A thermo fluid dynamic model of wood particle gasification- and combustion processes

    Directory of Open Access Journals (Sweden)

    G Boiger

    2016-09-01

    Full Text Available In order to qualitatively understand and evaluate the thermo- fluid dynamic situation within a wood gasification reactor, a 1D particle model has been created. The presented tool accounts for the highly in- stationary, kinetic- and thermo chemical effects, leading to partial gasification and combustion of a wood particle embedded within a packed bed collective. It considers the fluid- dynamic situation within the changing porous bulk structure of the packed bed, its impact on species- and heat transition mechanisms, the energy- and mass balances of wood, coal, pyrolysis-gas, wood- gas and off- gas phases, the thermodynamics of locally developing gasification- and combustion reaction equilibria, as well as the presence of the chemical species hydrogen, water, carbon (di- oxide, methane, oxygen, solid carbon and gaseous, longer chain hydrocarbons from pyrolysis. Model results can be shown to yield very good, qualitative agreement with measurements, found in literature.

  6. Tachyon Pole in σ Meson Propagator in Nuclear Matter in the Relativistic σ—ω Model

    Institute of Scientific and Technical Information of China (English)

    CHENWei; AIBao-Quan; 等

    2001-01-01

    The conditions that the tachyon pole of the σ meson propagator in nuclear matter appears are studied in the one-loop approximation in the relativistic σ-ω model.Different from the results of the previous paper,we find that the effect of the constant a in the self-interaction,U(σ)=aσ+1/2! bσ2+1/3!cσ3+1/4!dσ4,of the σ meson cannot be neglected.It determines the critical density where techyon appears.The smaller the a,the larger the critical density.The binding energy,pressure,incompressibility coefficient,nucleon effective mass are calculated and the relation between parameters to the tachyon pole is also studied.

  7. Development of a pathway model to assess the exposure of European pine trees to pine wood nematode via the trade of wood.

    Science.gov (United States)

    Douma, J C; van der Werf, W; Hemerik, L; Magnusson, C; Robinet, C

    2017-04-01

    Pine wood nematode (PWN), Bursaphelenchus xylophilus, is a threat for pine species (Pinus spp.) throughout the world. The nematode is native to North America, and invaded Japan, China, Korea, and Taiwan, and more recently Portugal and Spain. PWN enters new areas through trade in wood products. Once established, eradication is not practically feasible. Therefore, preventing entry of PWN into new areas is crucial. Entry risk analysis can assist in targeting management to reduce the probability of entry. Assessing the entry of PWN is challenging due to the complexity of the wood trade and the wood processing chain. In this paper, we develop a pathway model that describes the wood trade and wood processing chain to determine the structure of the entry process. We consider entry of PWN through imported coniferous wood from China, a possible origin of Portuguese populations, to Europe. We show that exposure increased over years due to an increase in imports of sawn wood. From 2000 to 2012, Europe received an estimated 84 PWN propagules from China, 88% of which arose from imported sawn wood and 12% from round wood. The region in Portugal where the PWN was first reported is among those with the highest PWN transfer per unit of imported wood due to a high host cover and vector activity. An estimated 62% of PWN is expected to enter in countries where PWN is not expected to cause the wilt of pine trees because of low summer temperatures (e.g., Belgium, Sweden, Norway). In these countries, PWN is not easily detected, and such countries can thus serve as potential reservoirs of PWN. The model identifies ports and regions with high exposure, which helps targeting monitoring and surveillance, even in areas where wilt disease is not expected to occur. In addition, we show that exposure is most efficiently reduced by additional treatments in the country of origin, and/or import wood from PWN-free zones. Pathway modelling assists plant health managers in analyzing risks along the

  8. Comparison of different models for the high-temperature heat-treatment of wood

    Energy Technology Data Exchange (ETDEWEB)

    Kocaefe, Duygu; Younsi, Ramdane; Poncsak, Sandor; Kocaefe, Yasar [Research Group on the Thermotransformation of Wood (GRTB), Department of Applied Sciences, University of Quebec at Chicoutimi, 555, boul. de l' Universite, Chicoutimi, Quebec (Canada)

    2007-07-15

    The high temperature thermal treatment of wood is an environment-friendly method for wood preservation. This technique has attracted considerable attention in recent years. The GRTB (groupe de recherche sur la thermotransformation du bois) at the University of Quebec at Chicoutimi, Canada, has been working on this subject for the past number of years. In this article, the work is presented with a focus on the mathematical modelling of the process. Three models (model based on Luikov's approach, diffusion model, and multiphase model) have been developed for the high temperature treatment of wood. The predictions of the models are compared with the experimental data. The diffusion model was found to be the most practical approach when the accuracy of the results and the computation times are both taken into account. (author)

  9. Molecular modeling of water interactions with fossil wood from Victorian brown coal

    Energy Technology Data Exchange (ETDEWEB)

    Tham Vu; Irene Yarovsky; Alan L. Chaffee [Monash University, Vic. (Australia). School of Chemistry

    2005-07-01

    The chemical structure of a fossil wood sample (Podocarpus sp.) taken from the Latrobe Valley coal measures (Victoria) was probed by {sup 13}C solid-state NMR, ultimate analyses and functional group analyses. This information was then used to create a molecular model (C{sub 100}H{sub 80}O{sub 2}) of fossil wood based on polymerized, but degraded lignin subunits. Molecular dynamics methods were used to observe both static and dynamic aspects of the coal-water interactions at ambient temperature, and to compare these with the analogous interactions for model lignin systems based on both guaiacyl (common to most woods) and syringyl (specific to angiosperms) structural units, as well as with bulk water. Na- and Ca-exchanged forms of the fossil wood model were also considered. The mobility of water was significantly reduced in all systems relative to bulk water, with the fossil wood and guaiacyl systems providing very similar values (global diffusion constants {approximately} 2.2 x 10{sup -5}cm{sup 2}{center_dot}s{sup -1}) and the Ca-exchanged system exhibiting the lowest value of all. A further reduction in the mobility of water molecules was observed in regions where hydrogen bonding could occur. For the fossil wood system, water molecules in the vicinity of carboxylic groups were significantly less mobile than those in the vicinity of OH groups generally. 22 refs., 8 figs., 2 tabs.

  10. Modelling polymer interactions of the 'molecular Velcro' type in wood under mechanical stress.

    Science.gov (United States)

    Altaner, C M; Jarvis, M C

    2008-08-07

    Trees withstand wind and snow loads by synthesising wood that varies greatly in mechanical properties: flexible in twigs and in the stem of the sapling, and rigid in the outer part of the mature stem. The 'molecular Velcro' model of Keckes et al. [2003. Cell-wall recovery after irreversible deformation of wood. Nat. Mater. 2, 810-814] permits the simulation of the tensile properties of water-saturated wood as found in living trees. A basic feature of this model is the presence of non-covalent interactions between hemicellulose chains attached to adjacent cellulose microfibrils, which are disrupted above a threshold level of interfibrillar shear. However, other evidence does not confirm the importance of hemicellulose-hemicellulose association in the cohesion of the interfibrillar matrix. Here, we present an alternative model in which hemicellulose chains bridging continuously from one microfibril aggregate (macrofibril) to the next provide most of the cohesion. We show that such hemicellulose bridges exist and that the stripping of the bridging chains from the cellulose surfaces under the tensile stress component normal to the macrofibrils can provide an alternative triggering mechanism for shear deformation between one macrofibril and the next. When one macrofibril then slides past another, a domain of the wood cell wall can extend but simultaneously it twists until the spacing between macrofibrils is reduced again and contact through hemicelluloses bridges is restored. Overall deformation therefore takes place through a series of local stick-slip events involving temporary twisting of small domains within the wood cell wall. Modelled load-deformation curves for this modified 'molecular Velcro' model are similar, although not identical, to those for the original model. However, the mechanism is different and more consistent with current views of the structure of wood cell walls, providing a framework within which the developmental control of rigidity in wood

  11. Modeling Wood Encroachment in Abandoned Grasslands in the Eifel National Park - Model Description and Testing.

    Directory of Open Access Journals (Sweden)

    Silvana Hudjetz

    Full Text Available The degradation of natural and semi-natural landscapes has become a matter of global concern. In Germany, semi-natural grasslands belong to the most species-rich habitat types but have suffered heavily from changes in land use. After abandonment, the course of succession at a specific site is often difficult to predict because many processes interact. In order to support decision making when managing semi-natural grasslands in the Eifel National Park, we built the WoodS-Model (Woodland Succession Model. A multimodeling approach was used to integrate vegetation dynamics in both the herbaceous and shrub/tree layer. The cover of grasses and herbs was simulated in a compartment model, whereas bushes and trees were modelled in an individual-based manner. Both models worked and interacted in a spatially explicit, raster-based landscape. We present here the model description, parameterization and testing. We show highly detailed projections of the succession of a semi-natural grassland including the influence of initial vegetation composition, neighborhood interactions and ungulate browsing. We carefully weighted the single processes against each other and their relevance for landscape development under different scenarios, while explicitly considering specific site conditions. Model evaluation revealed that the model is able to emulate successional patterns as observed in the field as well as plausible results for different population densities of red deer. Important neighborhood interactions such as seed dispersal, the protection of seedlings from browsing ungulates by thorny bushes, and the inhibition of wood encroachment by the herbaceous layer, have been successfully reproduced. Therefore, not only a detailed model but also detailed initialization turned out to be important for spatially explicit projections of a given site. The advantage of the WoodS-Model is that it integrates these many mutually interacting processes of succession.

  12. A model for establishing a win-win relationship between a wood pellets manufacturer and its customers

    Energy Technology Data Exchange (ETDEWEB)

    Uran, Vedran [ENERGETSKE USLUGE Ltd., Ilica 52, 10000, Zagreb (Croatia)

    2010-05-15

    This paper investigates the possibility of establishing a win-win relationship between a wood pellets manufacturer and its customers when the manufacturer possesses a power plant fueled by biomass and buys wood material from forest companies. Two prerequisites must be fulfilled for this relationship. First, the price of wood pellets should be lower than the fuel currently used by potential wood pellets customers and, second, the price of wood material as a raw material for producing the wood pellets should not jeopardize the profitability of the operations of the wood pellets manufacturer, who also produces electricity from biomass and sells it to the state at the feed-in tariff price. A mathematical model has been developed for each prerequisite and applied to several examples. The results demonstrate that a win-win relation can be established in Croatia and most of the Member States of the EU. (author)

  13. General model of wood in typical coupled tasks. Part I. – Phenomenological approach

    Directory of Open Access Journals (Sweden)

    Petr Koňas

    2008-01-01

    Full Text Available The main aim of this work is focused on FE modeling of wood structure. This task is conditioned mainly by different organized structures/regions (tissues, anomalies... and leads to homogenization process of multiphysics declaration of common scientific and engineering problems. The crucial role in this paper is played by derivation of coefficient form of general PDE which is solvable by nowadays numerical solvers. Generality of supposed model is given by wide range of coupled physical fields included in the model. Used approach summarizes and brings together models for various fields of matter and energy common in wood material in wood drying process, but is also suitable for a lot of different tasks of similar materials. Namely microwave drying of wood with orthotropic, visco-elastic material properties together with time, moisture and temperature dependency of structural strains by modified mechanical properties were included. Specific matrixes of elasticity for in­di­vi­dual fields were derived. Thermal field in wood was described by conduction type of spreading. Coupling of physical fields is based on diffusive character of temperature, moisture, static pressure fields movement.

  14. Modeling future U.S. forest sector market and trade impacts of expansion in wood energy consumption

    Science.gov (United States)

    Peter J. Ince; Andrew D. Kramp; Kenneth E. Skog; Do-il Yoo; V. Alaric Sample

    2011-01-01

    This paper describes an approach to modeling U.S. forest sector market and trade impacts of expansion in domestic wood energy consumption under hypothetical future U.S. wood biomass energy policy scenarios. The U.S. Forest Products Module (USFPM) was created to enhance the modeling of the U.S. forest sector within the Global Forest Products Model (GFPM), providing a...

  15. Multi-Criteria Decision-Making Model for the Material Flow of Resonant Wood Production

    Directory of Open Access Journals (Sweden)

    Patrik Aláč

    2017-03-01

    Full Text Available This paper proposes a multi-criteria decision-making model, for the selection and evaluation of the most valuable wooden input—resonant wood. Application of a given model can improve the process of input valuation as well as impact and improve particular economic indicators for the resonant wood manufacturer. We have tried to describe and evaluate the supply chain of resonant wood manufacturing and production of musical instruments. Particular value-added and non-value-added activities have been chosen according to the logical sequence of technology. Then, concrete criteria were specified and their significance weightings. Another important part of our paper is the description of resonant wood, specifications, and demands on log and wood species. There are some important physical and mechanical properties which should be taken into account and evaluated during the production of musical instruments. By the application of this model, a particular enterprise can reach an enhanced tool for the continuous evaluation of the product flowing through the supply chain. Visibility of particular operations and their logical sequence, presented by Petri nets, can lead to easier detection of possible defects in these operations and their origin. So, the main purpose of the paper lies in the suggestion of an objective and quantified managerial tool for the decision making.

  16. Modeling and designing of variable-period and variable-pole-number undulator

    Directory of Open Access Journals (Sweden)

    I. Davidyuk

    2016-02-01

    Full Text Available The concept of permanent-magnet variable-period undulator (VPU was proposed several years ago and has found few implementations so far. The VPUs have some advantages as compared with conventional undulators, e.g., a wider range of radiation wavelength tuning and the option to increase the number of poles for shorter periods. Both these advantages will be realized in the VPU under development now at Budker INP. In this paper, we present the results of 2D and 3D magnetic field simulations and discuss some design features of this VPU.

  17. Wood fuel technologies and group-oriented Timber Stand Improvement Program: model for waste wood utilization and resource renewal

    Energy Technology Data Exchange (ETDEWEB)

    1980-01-01

    Progress is reported on the following: educating and assisting landowners in the most efficient and profitable use of wood resources; developing local timber resources as energy alternatives by representing collective interests to Consumers Power, the woodchip industry, firewood retailers, country residents, and woodlot owners; and providing public information on the economics and methods of wood heat as a supplemental energy source. (MHR)

  18. Structure-function characterization of the crinkle-leaf peach wood phenotype: a future model system for wood properties research?

    Science.gov (United States)

    Variations in wood features of two genotypes of Prunus persica L. trees, wild-type and crinkle-leaf, were examined to elucidate the nature of weak wood in crinkle-leaf trees. Trees from three vigor classes (low, average, and high) of each genotype were sampled. No meaningful tendency of dissimilarit...

  19. Numerical Analysis of the Dynamic Behavior of a High Power Salient Pole Synchronous Machine by using a Corrected Model

    Directory of Open Access Journals (Sweden)

    CAMPEANU, A.

    2012-02-01

    Full Text Available In the paper is shown that, by using the circuit theory which operates with lumped parameters, it is possible to derive mathematical models of a high power salient pole synchronous machine (SPSM, that can take into account the basic processes of the machine. It offers results regarding the electromagnetic and mechanical stresses for a given practical application. The quantitative determinations were performed on an 8000 kW synchronous motor. The results of quantitative determinations are of essential interest in the designing stage, for dynamic characteristics and parameters derivation and for constructive solutions to be chosen.

  20. The Interactive Climate and Vegetation Along the Pole-Equator Belts Simulated by a Global Coupled Model

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The interaction between climate and vegetation along four Pole-Equator-Pole (PEP) belts were explored using a global two-way coupled model, AVIM-GOALS, which links the ecophysiological processes at the land surface with the general circulation model (GCM). The PEP belts are important in linking the climate change with the variation of sea and land, including terrestrial ecosystems. Previous PEP belts studies have mainly focused on the paleoclimate variation and its reconstruction. This study analyzes and discusses the interaction between modern climate and vegetation represented by leaf area index (LAI) and net primary production (NPP). The results show that the simulated LAI variation, corresponding to the observed LAI variation, agrees with the peak-valley variation of precipitation in these belts. The annual mean NPP simulated by the coupled model is also consistent with PIK NPP data in its overall variation trend along the four belts, which is a good example to promote global ecological studies by coupling the climate and vegetation models. A large discrepancy between the simulated and estimated LAI emerges to the south of 15°N along PEP 3 and to the south of 18°S in PEP 1S, and the discrepancy for the simulated NPP and PIK data in the two regions is relatively smaller in contrast to the LAI difference. Precipitation is a key factor affecting vegetation variation, and the overall trend of LAI and NPP corresponds more obviously to precipitation variation than temperature change along most parts of these PEP belts.

  1. Mathematical model for prediction of pyrolysis and ignition of wood under external heat flux

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The pyrolysis and ignition of combustible materials is an important aspect of the processes taking place in an unwanted fire. A prediction model presented in this paper is to study pyrolysis and ignition time of wood under external heat flux. The solution of the model provides the temperature at each point of the solid and the local solid conversion. And the time to ignition of the wood is predicted with the solution of surface temperature. In general, a good agreement between experimental and theoretical results is obtained.

  2. Mechanisms of particle-induced pulmonary inflammation in a mouse model: exposure to wood dust.

    Science.gov (United States)

    Määttä, Juha; Lehto, Maili; Leino, Marina; Tillander, Sari; Haapakoski, Rita; Majuri, Marja-Leena; Wolff, Henrik; Rautio, Sari; Welling, Irma; Husgafvel-Pursiainen, Kirsti; Savolainen, Kai; Alenius, Harri

    2006-09-01

    Repeated airway exposure to wood dust has long been known to cause adverse respiratory effects such as asthma and chronic bronchitis and impairment of lung function. However, the mechanisms underlying the inflammatory responses of the airways after wood dust exposure are poorly known. We used a mouse model to elucidate the mechanisms of particle-induced inflammatory responses to fine wood dust particles. BALB/c mice were exposed to intranasally administered fine (more than 99% of the particles had a particle size of dusts twice a week for 3 weeks. PBS, LPS, and titanium dioxide were used as controls. Intranasal instillation of birch or oak dusts elicited influx of inflammatory cells to the lungs in mice. Enhancement of lymphocytes and neutrophils was seen after oak dust exposure, whereas eosinophil infiltration was higher after birch dust exposure. Infiltration of inflammatory cells was associated with an increase in the mRNA levels of several cytokines, chemokines, and chemokine receptors in lung tissue. Oak dust appeared to be a more potent inducer of these inflammatory mediators than birch dust. The results from our in vivo mouse model show that repeated airway exposure to wood dust can elicit lung inflammation, which is accompanied by induction of several proinflammatory cytokines and chemokines. Oak and birch dusts exhibited quantitative and qualitative differences in the elicitation of pulmonary inflammation, suggesting that the inflammatory responses induced by the wood species may rise via different cellular mechanisms.

  3. CFD modeling and experience of waste-to-energy plant burning waste wood

    DEFF Research Database (Denmark)

    Rajh, B.; Yin, Chungen; Samec, N.

    2013-01-01

    Computational Fluid Dynamics (CFD) is being increasingly used in industry for in-depth understanding of the fundamental mixing, combustion, heat transfer and pollutant formation in combustion processes and for design and optimization of Waste-to-Energy (WtE) plants. In this paper, CFD modeling...... of waste wood combustion in a 13 MW grate-fired boiler in a WtE plant is presented. As a validation effort, the temperature profiles at a number of ports in the furnace are measured and the experimental results are compared with the CFD predictions. In the simulation, a 1D model is developed to simulate...... the conversion of the waste wood in the fuel bed on the grate, which provides the appropriate inlet boundary condition for the freeboard 3D CFD simulation. The CFD analysis reveals the detailed mixing and combustion characteristics in the waste wood-fired furnace, pinpointing how to improve the design...

  4. Assessment of structural integrity of wooden poles

    Science.gov (United States)

    Craighead, Ian A.; Thackery, Steve; Redstall, Martin; Thomas, Matthew R.

    2000-05-01

    Despite recent advances in the development of new materials, wood continues to be used globally for the support of overhead cable networks used by telecommunications and electrical utility companies. As a natural material, wood is subject to decay and will eventually fail, causing disruption to services and danger to public and company personnel. Internal decay, due to basidomycetes fungi or attack by termites, can progress rapidly and is often difficult to detect by casual inspection. The traditional method of testing poles for decay involves hitting them with a hammer and listening to the sound that results. However, evidence suggests that a large number of poles are replaced unnecessarily and a significant number of poles continue to fail unexpectedly in service. Therefore, a more accurate method of assessing the structural integrity of wooden poles is required. Over the last 25 years there have been a number of attempts at improving decay detection. Techniques such as ultrasound, drilling X rays etc. have been developed but have generally failed to improve upon the practicality and accuracy of the traditional testing method. The paper describes the use of signal processing techniques to analyze the acoustic response of the pole and thereby determine the presence of decay. Development of a prototype meter is described and the results of initial tests on several hundred poles are presented.

  5. A single cell model for pretreatment of wood by microwave explosion

    Science.gov (United States)

    Xianjun Li; Yongdong Zhou; Yonglin Yan; Zhiyong Cai; Fu Feng

    2010-01-01

    A theoretical model was developed to better understand the process of microwave explosion treatment of wood cells. The cell expansion and critical conditions concerning pressure and temperature of ray parenchyma cells in Eucalyptus urophylla were simulated during microwave pretreatment. The results indicate that longitudinal and circumferential stresses were generated...

  6. A Hysteresis Model Suitable For Numerical Simulation Of Moisture Content in Wood

    DEFF Research Database (Denmark)

    Frandsen, Henrik Lund; Svensson, Staffan; Damkilde, Lars

    2007-01-01

    The equilibrium moisture content in wood depends not only on the current relative humidity in the ambient air but also on the history of the relative humidity variations. This hysteresis dependency of sorption in wood implies that in the worst case the moisture content for a given relative humidi...... temperatures. These features make the model relatively easy to implement into a numerical method, e.g. the Finite Element Method....... may deviate by 30-35%. While researchers seem to have reached a general agreement on the hypothesis for the sorption hysteresis phenomenon, only a few models describing the phenomenon are available. Current models as the independent domain model have numerical deficiencies and drawbacks. This paper...... presents a new hysteresis model, which mathematically resolves in closed form expressions, with the current relative humidity and moisture content as the only input parameters. Furthermore, the model has the advantage of being applicable to different sorption isotherms, i.e. different species and different...

  7. Generalization of the model-independent Laurent-Pietarinen single-channel pole-extraction formalism to multiple channels

    CERN Document Server

    Svarc, Alfred; Osmanovic, Hedim; Stahov, Jugoslav; Tiator, Lothar; Workman, Ron L

    2015-01-01

    A method to extract resonance pole information from single-channel partial-wave amplitudes based on a Laurent (Mittag-Leffler) expansion and conformal mapping techniques has recently been developed. This method has been applied to a number of reactions and provides a model-independent extraction procedure which is particularly useful in cases where a set of amplitudes is available only at descrete energies. This method has been generalized and applied to the case of a multi-channel fit, where several sets of amplitudes are analysed simultaneously. The importance of unitarity constraints is discussed. The final result provides a powerful, model-independent tool for analyzing partial-wave amplitudes of coupled or connected channels based entirely on the concepts of analyticity and unitarity.

  8. Thermal modelling of the high temperature treatment of wood based on Luikov's approach

    Energy Technology Data Exchange (ETDEWEB)

    Younsi, R.; Kocaefe, D.; Poncsak, S.; Kocaefe, Y. [University of Quebec, Chicoutimi (Canada). Dept. of Applied Sciences

    2005-07-01

    A 3D, unsteady-state mathematical model was used to simulate the behaviour of wood during high temperature treatment. The model is based on Luikov's approach and solves a set of coupled heat and mass transfer equations. Using the model, the temperature and moisture content profiles of wood were predicted as a function of time for different heating rates. Parallel to the modelling study, an experimental study was carried out using small birch samples. The samples were subjected to high temperature treatment in a thermogravimetric system under different operating conditions. The experimental results and the model predictions were found to be in good agreement. The results show that the distributions of temperature and moisture content are influenced appreciably by the heating rate and the initial moisture content. (author)

  9. A simplified gis-based model for large wood recruitment and connectivity in mountain basins

    Science.gov (United States)

    Franceschi, Silvia; Antonello, Andrea; Vela, Ana Lucia; Cavalli, Marco; Crema, Stefano; Comiti, Francesco; Tonon, Giustino

    2015-04-01

    During the last 50 years in the Alps the decline of the rural and forest economy and at the depopulation of the mountain areas caused the progressive abandon of the land in general and in particular of the riparian zones and the consequent increment of the vegetation extension. On one hand the wood increases the availability of organic matter and has positive effects on mountain river systems. However, during flooding events large woods that reach the stream cause the clogging of bridges with an increase of flood hazard. The approach to the evaluation of the availability of large wood during flooding events is still a challenge. There are models that simulate the propagation of the logs downstream, but the evaluation of the trees that can reach the stream is still done using simplified GIS procedures. These procedures are the base for our research which will include LiDAR derived information on vegetation to evaluate large wood recruitment extreme events. Within the last Google Summer of Code (2014) we developed a set of tools to evaluate large wood recruitment and propagation along the channel network based on a simplified methodology for monitoring and modeling large wood recruitment and transport in mountain basins implemented by Lucía et 2014. These tools are integrated in the JGrassTools project as a dedicated section in the Hydro-Geomorphology library. The section LWRecruitment contains 10 simple modules that allow the user to start from very simple information related to geomorphology, flooding areas and vegetation cover and obtain a map of the most probable critical sections on the streams. The tools cover the two main aspects related to the iteration of large wood with the rivers: the recruitment mechanisms and the propagation downstream. While the propagation tool is very simple and does not consider the hydrodynamic of the problem, the recruitment algorithms are more specific and consider the influence of hillslopes stability and the flooding extension

  10. Modeling of high-temperature treatment of wood using the reaction engineering approach (REA).

    Science.gov (United States)

    Putranto, Aditya; Chen, Xiao Dong; Xiao, Zongyuan; Webley, Paul A

    2011-05-01

    A simple and accurate model of high-temperature treatment of wood can assist in the process design and the evaluation of performance of equipment. The high-temperature treatment of wood is essentially a drying process under linearly-increased gas temperature up to final temperature of 220-230°C which is a challenging process to model. This study is aimed to assess the applicability and accuracy of the reaction engineering approach (REA) to model the heat treatment of wood. In order to describe the process using the REA, the maximum activation energy (ΔE(v,b)) is evaluated according to the corresponding external conditions during the heat treatment. Results indicate that the REA coupled with the heat balance describes both moisture content and temperature profiles during the heat treatment very well. A good agreement towards the experimental data is indicated. It has also been shown that the current model is highly comparable in accuracy with the complex models.

  11. Modelling and simulation of wood chip combustion in a hot air generator system.

    Science.gov (United States)

    Rajika, J K A T; Narayana, Mahinsasa

    2016-01-01

    This study focuses on modelling and simulation of horizontal moving bed/grate wood chip combustor. A standalone finite volume based 2-D steady state Euler-Euler Computational Fluid Dynamics (CFD) model was developed for packed bed combustion. Packed bed combustion of a medium scale biomass combustor, which was retrofitted from wood log to wood chip feeding for Tea drying in Sri Lanka, was evaluated by a CFD simulation study. The model was validated by the experimental results of an industrial biomass combustor for a hot air generation system in tea industry. Open-source CFD tool; OpenFOAM was used to generate CFD model source code for the packed bed combustion and simulated along with an available solver for free board region modelling in the CFD tool. Height of the packed bed is about 20 cm and biomass particles are assumed to be spherical shape with constant surface area to volume ratio. Temperature measurements of the combustor are well agreed with simulation results while gas phase compositions have discrepancies. Combustion efficiency of the validated hot air generator is around 52.2 %.

  12. Double Porosity Models For the Description of Water Infiltration In Wood

    DEFF Research Database (Denmark)

    Kristian, Krabbenhøft; Damkilde, Lars

    2004-01-01

    In this paper some of the possibilities of applying double porosity and permeability models to the problem of water infiltration in wood are explored. It is shown that the double porosity model can capture a number of commonly reported anomalies including two-stage infiltration....../sorption and apparent sample length dependent transfer parameters. Starting with the double porosity model, several extensions are discussed and the type of principal behaviour possible with the models is elaborated on. Finally, a set of highly anomalous experimental results is fitted to within a reasonable accuracy...... by a double permeability model....

  13. Modelling, Simulation, Fabrication, Experiments and Real-Time Linear State Variable Feedback Control of Cuk Converter using Pole Placement Technique

    Science.gov (United States)

    Nanda, S.; Sengupta, M.; Sengupta, A.

    2014-01-01

    Using a suitable combination of some of the basic converter topologies representing the Buck, the Boost and the Buck-Boost converters, one may obtain some other useful dc-to-dc converters. A typical example is the cascade connection of the Boost and the Buck converter which produces the well known Cuk converter. This work emphasises on the modelling, real-time simulations, fabrication and closed-loop control of a Cuk converter. For the modelling and real time simulation, FPGA platform has been used. Small signal modelling and conventional control aspects (compensator) of Cuk converter are discussed. A 200W, 10kHz Cuk converter is designed, fabricated and tested in the laboratory. The converter model is of fourth order. The transfer function being a non-minimum phase one with two right-half plane zeroes, a limited work has been done on this. For such systems, conventional control methods are demonstrated to fail. Pole placement technique, which is envisaged to be a suitable control technique for a higher order non-minimum phase system has been adopted. Excellent correlation between off-line and real-time simulation results establishes the accuracy of the work. Agreement between open-loop results obtained from the experimental set-up under steady state vis-a-vis those obtained from simulation is also a major highlight of the paper.

  14. MODFLOW-USG model of groundwater flow in the Wood River Valley aquifer system in Blaine County, Idaho

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — A three-dimensional numerical groundwater flow model (MODFLOW-USG) was developed for the Wood River Valley (WRV) aquifer system, south-central Idaho, to evaluate...

  15. New Model of Wood Cell Wall Microfibril and Its Implications

    Science.gov (United States)

    Umesh P. Agarwal; Sally A. Ralph; Rick S. Reiner; Carlos Baez

    2015-01-01

    Traditionally it has been accepted that the cell walls are made up of microfibrils which are partly crystalline. However, based on the recently obtained Raman evidence that showed that the interior of the microfibril was significantly disordered and water accessible, a new model is proposed. In this model, the molecular chains of cellulose are still organized along the...

  16. Double porosity models for the description of water infiltration in wood

    DEFF Research Database (Denmark)

    Krabbenhøft, Kristian; Damkilde, Lars

    2004-01-01

    In this paper some of the possibilities of applying double porosity and permeability models to the problem of water infiltration in wood are explored. It is shown that the double porosity model can capture a number of commonly reported anomalies including two-stage infiltration....../sorption and apparent sample length dependent transfer parameters. Starting with the double porosity model, several extensions are discussed and the type of principal behaviour possible with the models is elaborated on. Finally, a set of highly anomalous experimental results is fitted to within a reasonable accuracy bv...

  17. Modeling wood dynamics, jam formation, and sediment storage in a gravel-bed stream

    Science.gov (United States)

    Eaton, B. C.; Hassan, M. A.; Davidson, S. L.

    2012-12-01

    In small and intermediate sized streams, the interaction between wood and bed material transport often determines the nature of the physical habitat, which in turn influences the health of the stream's ecosystem. We present a stochastic model that can be used to simulate the effects on physical habitat of forest fires, climate change, and other environmental disturbances that alter wood recruitment. The model predicts large wood (LW) loads in a stream as well as the volume of sediment stored by the wood; while it is parameterized to describe gravel bed streams similar to a well-studied field prototype, Fishtrap Creek, British Columbia, it can be calibrated to other systems as well. In the model, LW pieces are produced and modified over time as a result of random tree-fall, LW breakage, LW movement, and piece interaction to form LW jams. Each LW piece traps a portion of the annual bed material transport entering the reach and releases the stored sediment when the LW piece is entrained and moved. The equations governing sediment storage are based on a set of flume experiments also scaled to the field prototype. The model predicts wood loads ranging from 70 m3/ha to more than 300 m3/ha, with a mean value of 178 m3/ha: both the range and the mean value are consistent with field data from streams with similar riparian forest types and climate. The model also predicts an LW jam spacing that is consistent with field data. Furthermore, our modeling results demonstrate that the high spatial and temporal variability in sediment storage, sediment transport, and channel morphology associated with LW-dominated streams occurs only when LW pieces interact and form jams. Model runs that do not include jam formation are much less variable. These results suggest that river restoration efforts using engineered LW pieces that are fixed in place and not permitted to interact will be less successful at restoring the geomorphic processes responsible for producing diverse, productive

  18. Modeling of piezoelectric energy extraction in a thermoacoustic engine with multi-pole time-domain impedance

    Science.gov (United States)

    Lin, Jeffrey; Scalo, Carlo; Hesselink, Lambertus

    2015-11-01

    We have carried out the first high-fidelity Navier-Stokes simulation of a complete thermoacoustic engine with piezoelectric energy extraction. The standing-wave thermoacoustic piezoelectric (TAP) engine model comprises a 51 cm long cylindrical resonator, containing a thermoacoustic stack on one end and capped by a PZT-5A piezoelectric diaphragm on the other end, tuned to the frequency of the thermoacoustically-amplified mode (388 Hz). A multi-pole broadband time-domain impedance model has been adopted to accurately simulate the measured electromechanical properties of the piezoelectric diaphragm. Simulations are first carried out from quasi-quiescent conditions to a limit cycle, with varying temperature gradients and stack configurations. Stack geometry and boundary layers are fully resolved. Acoustic energy extraction is then activated, achieving a new limit cycle at lower pressure amplitudes. The scaling of the modeled electrical power output and attainable thermal-to-electric energy conversion efficiencies are discussed. Limitations of extending a quasi-one-dimensional linear approximation based on Rott's theory to a (low amplitude) limit cycle are discussed, as well as nonlinear effects such as thermoacoustic energy transport and viscous dissipation.

  19. Cepstrum-based operational modal analysis revisited: A discussion on pole-zero models and the regeneration of frequency response functions

    Science.gov (United States)

    Smith, Wade A.; Randall, Robert B.

    2016-10-01

    Operational modal analysis (OMA) seeks to determine a structure's dynamic characteristics from response-only measurements, which comprise both excitation and transmission path effects. The cepstrum has been used successfully in a number of applications to separate these source and path effects, after which the poles and zeros of the transfer function can be obtained via a curve-fitting process. The contributions from the individual poles and zeros can then be added (in log magnitude) to regenerate the frequency response function (FRF). Cepstrum-based OMA was originally developed in the 1980s and 90s, but there have been a number of recent developments that warrant discussion and explanation, and this is the basis of the present paper, which focusses on the FRF regeneration process and on a number of broader points explaining FRFs from a pole-zero perspective. The FRF regenerated from identified poles and zeros is subject to magnitude distortion from the effects of truncation, i.e., from the residual effects of out-of-band poles and zeros. As long as a reference FRF is available - for example from conventional experimental modal analysis or from a finite element model - this distortion can be corrected for using a magnitude equalisation curve. This paper discusses the nature of this equalisation curve, and gives recommendations on how best to obtain it. Other topics covered in the discussion are: the required distribution of poles and zeros for the successful regeneration of FRFs; node points and weak modes in a pole-zero model; the differences in pole-zero distribution between receptance, mobility and accelerance FRF forms; and, how to deal with the very low frequency region when regenerating FRFs. Special consideration is given to the identification of zeros - often masked by noise in response measurements - using transmissibility estimation. It is hoped that the discussion will assist in the application of cepstrum-based OMA methods and will lead to improved

  20. Neural network modeling of conditions of destruction of wood plank based on measurements

    Science.gov (United States)

    Filkin, V.; Kaverzneva, T.; Lazovskaya, T.; Lukinskiy, E.; Petrov, A.; Stolyarov, O.; Tarkhov, D.

    2016-11-01

    The paper deals with the possibility of predicting the ultimate load breaking timber sample based on the loading force dependence on the deflection before destruction. Prediction of mechanical properties of wood is handicapped by complex anisotropic structures. The anisotropic nature of the material and, in a great measure, the random nature of wood grain local features defining moment of destruction lead to a significant dependence of the required load on the individual characteristics of a particular bar. The ultimate load is sought as a function of the coefficients of the neural network approximation of the loading force dependence on the deflection. For this purpose, a number of experiments on timber sample loading until the destruction is conducted. Modeling of the conditions of material destruction may provide the required safety control in building industry.

  1. Observations and modeling of ionospheric scintillations at South Pole during six X‐class solar flares in 2013

    National Research Council Canada - National Science Library

    Priyadarshi, S; Zhang, Q.‐H; Ma, Y.‐Z; Wang, Y; Xing, Z.‐Y

    2016-01-01

    ...‐class solar flares have been studied during the summer and winter months, using the produced scintillation indices based on the observations from the GPS receiver at South Pole and the in situ plasma...

  2. High-Resolution Vector Magnetograms of the Sun's Poles from Hinode: Flux Distributions and Global Coronal Modeling

    Science.gov (United States)

    Petrie, Gordon

    2017-01-01

    The Sun's polar fields play a leading role in structuring the large-scale solar atmosphere and in determining the interplanetary magnetic field. They are also believed to supply the seed field for the subsequent solar activity cycle. However, present-day synoptic observations do not have sufficient spatial resolution or sensitivity to diagnose accurately the high-latitude magnetic vector field. The high spatial resolution and sensitivity of the full-Stokes observations from the Hinode Solar Optical Telescope Spectro-Polarimeter, observing the poles long-term, allows us to build up a detailed picture of the Cycle 24 polar field reversal, including the changing latitude distribution of the high-latitude flux, and to study the effect on global coronal field models. The Hinode observations provide detailed information on the dominant facular-scale magnetic structure of the polar fields, and their field inclination and flux distribution. Hybrid synoptic magnetograms are constructed from Hinode polar measurements and full-disk magnetograms from the Synoptic Optical Long-term Investigations of the Sun (SOLIS) Vector Spectro-Magnetograph (VSM), and coronal potential field models are calculated. Loss of effective spatial resolution at the highest latitudes presents complications. Possible improvements to synoptic polar data are discussed.

  3. ALMA Imaging and Gravitational Lens Models of South Pole Telescope-Selected Dusty, Star-Forming Galaxies at High Redshifts

    CERN Document Server

    Spilker, Justin; Aravena, Manuel; Bethermin, Matthieu; Bothwell, Matt; Carlstrom, John; Chapman, Scott; Crawford, Tom; de Breuck, Carlos; Fassnacht, Chris; Gonzalez, Anthony; Greve, Thomas; Hezaveh, Yashar; Litke, Katrina; Ma, Jingzhe; Malkan, Matt; Rotermund, Kaja; Strandet, Maria; Vieira, Joaquin; Weiss, Axel; Welikala, Niraj

    2016-01-01

    The South Pole Telescope has discovered one hundred gravitationally lensed, high-redshift, dusty, star-forming galaxies (DSFGs). We present 0.5" resolution 870um Atacama Large Millimeter/submillimeter Array imaging of a sample of 47 DSFGs spanning z=1.9-5.7, and construct gravitational lens models of these sources. Our visibility-based lens modeling incorporates several sources of residual interferometric calibration uncertainty, allowing us to properly account for noise in the observations. At least 70% of the sources are strongly lensed by foreground galaxies (mu_870um > 2), with a median magnification mu_870um = 6.3, extending to mu_870um > 30. We compare the intrinsic size distribution of the strongly lensed sources to a similar number of unlensed DSFGs and find no significant differences in spite of a bias between the magnification and intrinsic source size. This may indicate that the true size distribution of DSFGs is relatively narrow. We use the source sizes to constrain the wavelength at which the du...

  4. Effects of forest management on sustainability of integrated timber and energy wood production. Scenario analysis based on ecosystem model simulations

    Energy Technology Data Exchange (ETDEWEB)

    Routa, J.

    2011-07-01

    The main aim of this thesis was to study the effects of forest management on the sustainability of integrated timber and energy wood production in Norway spruce (Picea abies (L.) Karst.), on fertile and medium fertile sites, and Scots pine (Pinus sylvestris L.), on medium fertile and less fertile sites. In this context, an ecosystem model was used in scenario analyses, which considered the effects of management on the total stem wood production, timber and energy wood production. Furthermore, the management implications for net present value (NPV) and net CO{sub 2} emissions of the use of energy wood was addressed. The management included varying pre-commercial stand density, timing, and intensity of energy wood thinning, N fertilization (Papers 2-4), and rotation length (Paper 4). In addition, the effects of the genetic entry on above-ground biomass production of Norway spruce were studied based on experimental data (Paper 1). In general, the management with higher pre-commercial stand density than that used in basic management and N fertilization clearly increased stem wood production (i.e. sawlogs, pulp and small-sized stem wood), energy wood production (logging residuals, small-sized stem wood, stump wood and roots) and also NPV over the rotation for both Norway spruce and Scots pine, regardless of site fertility type and rotation length used in the simulations (Papers 2-4). However, the total stem wood production and energy wood production were also affected by the timing of energy wood thinning. Fertilization had a positive effect, but the effects of number of applications and amount of N fertilization were negligible on the total stem wood and energy wood production. Additionally, in the case of net CO{sub 2} emissions, the increase of pre-commercial stand density and fertilization clearly decreased the net CO{sub 2} emission in energy production over the rotation regardless of tree species, site fertility type and rotation length used in simulations (Papers

  5. Modeling the Effect of Helical Fiber Structure on Wood Fiber Composite Elastic Properties

    Science.gov (United States)

    Marklund, Erik; Varna, Janis

    2009-08-01

    The effect of the helical wood fiber structure on in-plane composite properties has been analyzed. The used analytical concentric cylinder model is valid for an arbitrary number of phases with monoclinic material properties in a global coordinate system. The wood fiber was modeled as a three concentric cylinder assembly with lumen in the middle followed by the S3, S2 and S1 layers. Due to its helical structure the fiber tends to rotate upon loading in axial direction. In most studies on the mechanical behavior of wood fiber composites this extension-twist coupling is overlooked since it is assumed that the fiber will be restricted from rotation within the composite. Therefore, two extreme cases, first modeling fiber then modeling composite were examined: (i) free rotation and (ii) no rotation of the cylinder assembly. It was found that longitudinal fiber modulus depending on the microfibril angle in S2 layer is very sensitive with respect to restrictions for fiber rotation. In-plane Poisson’s ratio was also shown to be greatly influenced. The results were compared to a model representing the fiber by its cell wall and using classical laminate theory to model the fiber. It was found that longitudinal fiber modulus correlates quite well with results obtained with the concentric cylinder model, whereas Poisson’s ratio gave unsatisfactory matching. Finally using typical thermoset resin properties the longitudinal modulus and Poisson’s ratio of an aligned softwood fiber composite with varying fiber content were calculated for various microfibril angles in the S2 layer.

  6. Periodically poled silicon

    Science.gov (United States)

    Hon, Nick K.; Tsia, Kevin K.; Solli, Daniel R.; Khurgin, Jacob B.; Jalali, Bahram

    2010-02-01

    Bulk centrosymmetric silicon lacks second-order optical nonlinearity χ(2) - a foundational component of nonlinear optics. Here, we propose a new class of photonic device which enables χ(2) as well as quasi-phase matching based on periodic stress fields in silicon - periodically-poled silicon (PePSi). This concept adds the periodic poling capability to silicon photonics, and allows the excellent crystal quality and advanced manufacturing capabilities of silicon to be harnessed for devices based on χ(2)) effects. The concept can also be simply achieved by having periodic arrangement of stressed thin films along a silicon waveguide. As an example of the utility, we present simulations showing that mid-wave infrared radiation can be efficiently generated through difference frequency generation from near-infrared with a conversion efficiency of 50% based on χ(2) values measurements for strained silicon reported in the literature [Jacobson et al. Nature 441, 199 (2006)]. The use of PePSi for frequency conversion can also be extended to terahertz generation. With integrated piezoelectric material, dynamically control of χ(2)nonlinearity in PePSi waveguide may also be achieved. The successful realization of PePSi based devices depends on the strength of the stress induced χ(2) in silicon. Presently, there exists a significant discrepancy in the literature between the theoretical and experimentally measured values. We present a simple theoretical model that produces result consistent with prior theoretical works and use this model to identify possible reasons for this discrepancy.

  7. Adapting transport modes to supply chains classified by the uncertainty supply chain model: A case study at Manaus Industrial Pole

    Directory of Open Access Journals (Sweden)

    Fabiana Lucena Oliveira

    2017-01-01

    Full Text Available This paper discusses transport modes supporting Uncertainty Supply Chain Model (USCM in the case of Manaus Industrial Pole (PIM, an industrial cluster in the Brazilian Amazon that hosts six hundred factories with diverse logistics and supply chain managerial strategies. USCM (Lee, 2002; Fisher, 1997develops a dot matrix classification of the supply chains considering several attributes (e.g., agility, cost, security, responsiveness and argues that emergent economies industrial clusters, in the effort to keep attractiveness for technological frontier firms, need to adapt supply chain strategies according to USCM attributes. The paper takes a further step, discussing which transport modes are suitable to each supply chain classified at the USCM in PIM´s case. The research´s methods covered the use of PIM´s statistical official database (secondary data, interviews with the main logistical services providers of PIM and phone survey with a sample of firms (primary data. Findings confirm the theoretical argument that different supply chains will demand different transport modes running at the same time in the same industrial cluster (Oliveira, 2009. In the case of PIM, this implies investments on port and airport infrastructure and a strategic focus on air transport mode, due to (1 short life cycle of products, (2 distance from suppliers, (3 quick response to demand and (4 the fact that even PIM´s standard products use, in average, forty per cent of air transport at inbound logistics.

  8. Modeling of the fast organic emissions from a wood-finishing product—Floor wax

    Science.gov (United States)

    Chang, John C. S.; Guo, Zhishi

    Environmental chamber and full-scale residential house tests were conducted to evaluate the fast organic emissions from a wood-finishing product—floor wax. For the environmental chamber tests, a very small amount of (wax was applied to an aluminum plate. It was found that the chamber exit organic concentrations can be estimated by a model with an initial condition of instant organic emissions. The model was applied to the house data to interpret the octane and nonane emissions. Significant sink effects were found in the house that prolonged the elevated octane and nonane concentrations for more than 2 days.

  9. Two center shell model with Woods-Saxon potentials: adiabatic and diabatic states in fusion

    CERN Document Server

    Díaz-Torres, A; Diaz-Torres, Alexis; Scheid, Werner

    2005-01-01

    A realistic two-center shell model for fusion is proposed, which is based on two spherical Woods-Saxon potentials and the potential separable expansion method. This model describes the single-particle motion in a fusing system. A technique for calculating stationary diabatic states is suggested which makes use of the formal definition of those states, i.e., they minimize the radial nonadiabatic coupling between the adiabatic states. As an example the system $^{16}$O + $^{40}$Ca $\\to$ $^{56}$Ni is discussed.

  10. 1-D air-snowpack modeling of atmospheric nitrous acid at South Pole during ANTCI 2003

    Directory of Open Access Journals (Sweden)

    Wei Liao

    2008-05-01

    Full Text Available A 1-D air-snowpack model of HONO has been developed and constrained by observed chemistry and meteorology data. The 1-D model includes molecular diffusion and mechanical dispersion, windpumping in snow, gas phase to quasi-liquid layer phase HONO transfer and quasi-liquid layer nitrate and interstitial air HONO photolysis. Photolysis of nitrate is important as a dominant HONO source inside the snowpack, however, the observed HONO emission from the snowpack was triggered mainly by the equilibrium between quasi liquid layer nitrite and firn air HONO deep down the snow surface (i.e. 30 cm below snow surface. The high concentration of HONO in the firn air is subsequently transported above the snowpack by diffusion and windpumping. The model uncertainties come mainly from lack of measurements and the interpretation of the QLL properties based on the bulk snow measurements. One critical factor is the ionic strength of QLL nitrite, which is estimated here by the bulk snow pH, nitrite concentration, and QLL to bulk snow volume ratio.

  11. 1-D Air-snowpack modeling of atmospheric nitrous acid at South Pole during ANTCI 2003

    Directory of Open Access Journals (Sweden)

    W. Liao

    2008-12-01

    Full Text Available A 1-D air-snowpack model of HONO has been developed and constrained by observed chemistry and meteorology data. The 1-D model includes molecular diffusion and mechanical dispersion, windpumping in snow, gas phase to quasi-liquid layer phase HONO transfer and quasi-liquid layer nitrate and interstitial air HONO photolysis. Photolysis of nitrate is important as a dominant HONO source inside the snowpack, however, the observed HONO emission from the snowpack was triggered mainly by the equilibrium between quasi liquid layer nitrite and firn air HONO deep down the snow surface (i.e. 30 cm below snow surface. The high concentration of HONO in the firn air is subsequently transported above the snowpack by diffusion and windpumping. The model uncertainties come mainly from lack of measurements and the interpretation of the QLL properties based on the bulk snow measurements. One critical factor is the ionic strength of QLL nitrite, which is estimated here by the bulk snow pH, nitrite concentration, and QLL to bulk snow volume ratio.

  12. Relação das propriedades mecânicas e densidade de postes de madeira de eucalipto com seu estado de deterioração Relationship between mechanical properties and density of the eucalyptus wood poles with their deterioration staturs

    Directory of Open Access Journals (Sweden)

    Rafael Colombo Abruzzi

    2012-12-01

    deterioration presenting similar residual mechanical strength. This behavior can be explained by the influence of wood density on the correlations between mechanical properties and the state of deterioration of the poles. Less dense woods can have residual mechanical strength low even without present signs of deterioration. The study of the characterization of eucalyptus wood indicated that the state of deterioration measured by field inspection alone is not a good indicator for predicting the durability of wood structures, making necessary a preliminary analysis of the density.

  13. Mixed mesh/nodal magnetic equivalent circuit modeling of a six-phase claw-pole automotive alternator

    Science.gov (United States)

    Horvath, Daniel C.

    must eliminate these elements and establish new KVL loops with the remaining non-infinite components. Researchers have developed algorithms to automate the loop construction process [4]. However, the algorithms require one to categorize all potential overlap positions, which is a challenge for claw-pole machines. One does not experience this issue in nodal-based solution techniques. However, since machines tend to operate in saturation, issues of convergence are often encountered. In this research, an alternative solution technique is provided in which mesh analysis is used in all magnetically nonlinear flux tubes while nodal analysis is used to solve for quantities in the airgap. This has the potential to use the advantage of each solution technique. This research builds upon that presented in [5], in which permeance expressions for all flux tubes were developed for a nodal MEC model of a three-phase claw-pole alternator with a delta-connected stator. In addition to the mixed mesh/nodal system a second focus is to explore new model configurations including six-phase machines with wye-connected stator and permanent magnets on the rotor. Validation of the models that are proposed is performed using both FEA models and experimental data from commercially-available alternators.

  14. Moisture Transport in Wood

    DEFF Research Database (Denmark)

    Astrup, T.; Hansen, K. K.; Hoffmeyer, P.

    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....

  15. Moisture Transport in Wood

    DEFF Research Database (Denmark)

    Astrup, T.; Hansen, K. K.; Hoffmeyer, P.;

    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....

  16. A mouse model of ocular blast injury that induces closed globe anterior and posterior pole damage

    Science.gov (United States)

    Hines-Beard, Jessica; Marchetta, Jeffrey; Gordon, Sarah; Chaum, Edward; Geisert, Eldon E.; Rex, Tonia S.

    2012-01-01

    We developed and characterized a mouse model of primary ocular blast injury. The device consists of: a pressurized air tank attached to a regulated paintball gun with a machined barrel; a chamber that protects the mouse from direct injury and recoil, while exposing the eye; and a secure platform that enables fine, controlled movement of the chamber in relation to the barrel. Expected pressures were calculated and the optimal pressure transducer, based on the predicted pressures, was positioned to measure output pressures at the location where the mouse eye would be placed. Mice were exposed to one of three blast pressures (23.6, 26.4, or 30.4psi). Gross pathology, intraocular pressure, optical coherence tomography, and visual acuity were assessed 0, 3, 7, 14, and 28 days after exposure. Contralateral eyes and non-blast exposed mice were used as controls. We detected increased damage with increased pressures and a shift in the damage profile over time. Gross pathology included corneal edema, corneal abrasions, and optic nerve avulsion. Retinal damage was detected by optical coherence tomography and a deficit in visual acuity was detected by optokinetics. Our findings are comparable to those identified in Veterans of the recent wars with closed eye injuries as a result of blast exposure. In summary, this is a relatively simple system that creates injuries with features similar to those seen in patients with ocular blast trauma. This is an important new model for testing the short-term and long-term spectrum of closed globe blast injuries and potential therapeutic interventions. PMID:22504073

  17. LEACHING MECHANISM OF CHROMATED COPPER ARSENATE (CCA WOOD PRESERVATIVE

    Directory of Open Access Journals (Sweden)

    Engin Derya Gezer

    2004-04-01

    Full Text Available In recent years, the increase demand on wooden raw materials and destroyed forest area (i.e clear cutting led to pressure on forest resources. Thus, Wood used in outdoor applications should be treated with preservatives to extent service life. in our country, although there is no regulations or any standards to be obeyed to preserve wood materials, averagely, 400.000 m3 /per year utility poles manufactured from softwood species and 30.000 m3/per year rail road slippers produced from either hardwood species or softwood species have been impregnated with wood preservatives. Chromated copper arsenic (CCA is commonly used wood preservatives to preserve utility poles in our country. According to data taken from Turkish Electricity Transmission Company (TEDAS 208.000 utility poles are used in Trabzon city area, 180.000 utility poles are in Rize city area, 121.000 utility poles are used in Artvin. Roughly 17.000 utility poles are replaced every year in three cities. Determining leaching factors of treated wood is important for explaining the short service life of utility poles treated with CCA used in Black Sea area. Factors such as preservative formulation, fixation temperature, post-treatment handling, wood dimensions, leaching media, pH, salinity and temperature have been shown to effect leaching of CCA treated wood.

  18. Numeric model of the normative consumption of heat for the colour homogenisation of wood in pressure autoclaves

    Science.gov (United States)

    Dzurenda, Ladislav

    2016-06-01

    This paper presents a numeric model of the normative consumption of heat for the colour homogenisation of unfrozen wood using saturated steam in pressure autoclaves, in the form of a technically feasible standard. For more effective determination of the objectively necessary consumption of heat for steaming non-frozen wood in a steam autoclave, a program was prepared in EXCEL in the form of a numeric table. Based on the technical and technological data on machinery, the range of colour homogenised wood and the colour-homogenisation regime, the program provides information about normative - the consumption of heat per 1 mł - of colour homogenised wood as well as about the consumption of heat for individual items of the thermal balance off the process of colour homogenisation in a pressure autoclave.

  19. Modeling stump biomass of stands using harvester measurements for adaptive energy wood procurement systems

    Energy Technology Data Exchange (ETDEWEB)

    Vesa, Lauri [ForestCalc Consulting Oy Ltd., 80230 Joensuu (Finland); Palander, Teijo [School of Forest Sciences, University of Eastern Finland, 80100 Joensuu (Finland)

    2010-09-15

    The value and volumes of industrial stump fuel supply are increasing for energy production. Accurate estimates of aboveground and belowground biomass of trees are important when estimating the potential of stumps as a bioenergy source. In this study two stump biomass equations were adapted and tested using them as calibrated stump biomass models computed as the cumulative sum by a local stand. In addition, variables derived from stem measurements of the forest harvester data were examined to predict stump biomass of a stand by applying regression analysis. The true stump yield (dry weight) was used as the reference data in the study. Both biomass models performed well (adjusted R{sup 2} {proportional_to} 0.84) and no advance was found in using other stem dimensions as independent variables in the model. The stand-level model can be used in innovative stump biomass prediction tools for increasing efficiency of energy wood procurement planning to stands within a certain area. In practice, wood procurement managers would need to adapt developed system and decide whether the degree of accuracy/precision provided by the models is acceptable in their local stand harvesting conditions. (author)

  20. A Revised Multi-Fickian Moisture Transport Model To Describe Non-Fickian Effects In Wood

    DEFF Research Database (Denmark)

    Frandsen, Henrik Lund; Svensson, Staffan; Damkilde, Lars

    2007-01-01

    This paper presents a study and a refinement of the sorption rate model in a so-called multi-Fickian or multiphase model. This type of model describes the complex moisture transport system in wood, which consists of separate water vapor and bound-water diffusion interacting through sorption....... At high relative humidities, the effect of this complex moisture transport system becomes apparent, and since a single Fickian diffusion equation fails to model the behavior, it has been referred to as non-Fickian or anomalous behavior. At low relative humidities, slow bound-water transport and fast...... conditions for the model are discussed, since discrepancies from corresponding models of moisture transport in paper products have been found....

  1. A revised multi-Fickian moisture transport model to describe non-Fickian effects in wood

    DEFF Research Database (Denmark)

    Frandsen, Henrik Lund; Damkilde, Lars; Svensson, Staffan

    2007-01-01

    This paper presents a study and a refinement of the sorption rate model in a so-called multi-Fickian or multi-phase model. This type of model describes the complex moisture transport system in wood, which consists of separate water vapor and bound-water diffusion interacting through sorption....... At high relative humidities, the effect of this complex moisture transport system becomes apparent, and since a single Fickian diffusion equation fails to model the behavior, it has been referred to as non-Fickian or anomalous behavior. At low relative humidities, slow bound-water transport and fast...... conditions for the model are discussed, since discrepancies from corresponding models of moisture transport in paper products have been found. ©2007 by Walter de Gruyter....

  2. Modeling Wood Fibre Length in Black Spruce (Picea mariana (Mill. BSP Based on Ecological Land Classification

    Directory of Open Access Journals (Sweden)

    Elisha Townshend

    2015-09-01

    Full Text Available Effective planning to optimize the forest value chain requires accurate and detailed information about the resource; however, estimates of the distribution of fibre properties on the landscape are largely unavailable prior to harvest. Our objective was to fit a model of the tree-level average fibre length related to ecosite classification and other forest inventory variables depicted at the landscape scale. A series of black spruce increment cores were collected at breast height from trees in nine different ecosite groups within the boreal forest of northeastern Ontario, and processed using standard techniques for maceration and fibre length measurement. Regression tree analysis and random forests were used to fit hierarchical classification models and find the most important predictor variables for the response variable area-weighted mean stem-level fibre length. Ecosite group was the best predictor in the regression tree. Longer mean fibre-length was associated with more productive ecosites that supported faster growth. The explanatory power of the model of fitted data was good; however, random forests simulations indicated poor generalizability. These results suggest the potential to develop localized models linking wood fibre length in black spruce to landscape-level attributes, and improve the sustainability of forest management by identifying ideal locations to harvest wood that has desirable fibre characteristics.

  3. Modeling of electrodialytic and dialytic removal of Cr, Cu and As from CCA-treated wood chips

    DEFF Research Database (Denmark)

    Ribeiro, Alexandra; Rodriguez-Maroto, J.M.; Mateus, Eduardo

    2007-01-01

    A one-dimensional model is developed for simulating the electrodialytic and dialytic treatment of a saturated bed of wood chips containing chromium, copper and arsenic. The movement of Cr, Cu and As is mathematically modeled taking into account the diffusion transport resulting from the concentra......A one-dimensional model is developed for simulating the electrodialytic and dialytic treatment of a saturated bed of wood chips containing chromium, copper and arsenic. The movement of Cr, Cu and As is mathematically modeled taking into account the diffusion transport resulting from......+ and NO3 used as electrolyte solutions in the electrode compartments, and oxalate ions and protons incorporated with the oxalic acid solution during wood chips incubation. The model simulation also takes into account that OH generated on the cathode, during electrodialytic remediation, is periodically...

  4. CFD modeling and experience of waste-to-energy plant burning waste wood

    OpenAIRE

    Rajh, B.; Yin, Chungen; Samec, N.; M. HRIBERSEK; Kokalj, F.

    2013-01-01

    Computational Fluid Dynamics (CFD) is being increasingly used in industry for in-depth understanding of the fundamental mixing, combustion, heat transfer and pollutant formation in combustion processes and for design and optimization of Waste-to-Energy (WtE) plants. In this paper, CFD modeling of waste wood combustion in a 13 MW grate-fired boiler in a WtE plant is presented. As a validation effort, the temperature profiles at a number of ports in the furnace are measured and the experimental...

  5. Advanced modelling and testing of a 13 MWth waste wood-fired grate boiler with recycled flue gas

    DEFF Research Database (Denmark)

    Rajh, Boštjan; Yin, Chungen; Samec, Niko

    2016-01-01

    Numerical modelling is widely used in industry for detailed understanding of the combustion process and for appropriate design and optimization of biomass/waste-fired boilers. This paper presents a numerical study of a 13 MWth waste wood-fired grate boiler, based on the coupled in-bed fuel...... conversion modelling and freeboard combustion modelling methodology. A 1D model is developed for the conversion of the waste wood in the fuel bed on the grate, providing the appropriate grate inlet condition for the 3D simulation of the freeboard region. Since part of the flue gas is recycled into the boiler...

  6. 3D multiscale micromechanical model of wood: From annual rings to microfibrils

    DEFF Research Database (Denmark)

    Qing, Hai; Mishnaevsky, Leon

    2010-01-01

    A 3D micromechanical analytical-computational model of softwood, which takes into account the wood microstructures at four scale levels, from microfibrils to annual rings, is developed. For the analysis of the effect of the annual rings structure on the properties of softwood, an improved rule......-of-mixture model, based on 3D orthotropic stress–strain relations and taking into account the compatibility of deformations at the interface of two phases and equilibrium of tractions at phase boundaries, is proposed. The improved rule of mixture model (IRoM) was compared with the classical rule-of-mixture (Ro......M) and finite element method (FEM) simulations. It was shown that IRoM gives almost as good results as FEM. The analytical model of annual rings is combined with the 3D finite element model of softwood as cellular material with multilayered, microfibril reinforced cell walls, developed by (Qing and Mishnaevsky...

  7. Groundwater-flow model for the Wood River Valley aquifer system, south-central Idaho

    Science.gov (United States)

    Fisher, Jason C.; Bartolino, James R.; Wylie, Allan H.; Sukow, Jennifer; McVay, Michael

    2016-06-27

    A three-dimensional numerical model of groundwater flow was developed for the Wood River Valley (WRV) aquifer system, Idaho, to evaluate groundwater and surface-water availability at the regional scale. This mountain valley is located in Blaine County and has a drainage area of about 2,300 square kilometers (888 square miles). The model described in this report can serve as a tool for water-rights administration and water-resource management and planning. The model was completed with support from the Idaho Department of Water Resources, and is part of an ongoing U.S. Geological Survey effort to characterize the groundwater resources of the WRV. A highly reproducible approach was taken for constructing the WRV groundwater-flow model. The collection of datasets, source code, and processing instructions used to construct and analyze the model was distributed as an R statistical-computing and graphics package.

  8. Complex geometries in wood

    DEFF Research Database (Denmark)

    Tamke, Martin; Ramsgaard Thomsen, Mette; Riiber Nielsen, Jacob

    2009-01-01

    The versatility of wood constructions and traditional wood joints for the production of non standard elements was in focus of a design based research. Herein we established a seamless process from digital design to fabrication. A first research phase centered on the development of a robust parame...... parametric model and a generic design language a later explored the possibilities to construct complex shaped geometries with self registering joints on modern wood crafting machines. The research was carried out as collaboration with industrial partners....

  9. Orthogonal model and experimental data for analyzing wood-fiber-based tri-axial ribbed structural panels in bending

    Science.gov (United States)

    Jinghao Li; John F. Hunt; Shaoqin Gong; Zhiyong Cai

    2017-01-01

    This paper presents an analysis of 3-dimensional engineered structural panels (3DESP) made from wood-fiber-based laminated paper composites. Since the existing models for calculating the mechanical behavior of core configurations within sandwich panels are very complex, a new simplified orthogonal model (SOM) using an equivalent element has been developed. This model...

  10. SIMULATION OF EARTH'S POLES DYNAMICS USING ASK-ANALYSIS

    OpenAIRE

    Cherednychenko N. A.; Lutsenko Y. V.; Trunev A. P.

    2014-01-01

    Based on local semantic information models, we have examined the dependence of the dynamics of the displacement of the pole positions of celestial objects. We have also developed and differentiated an analysis of ASK-pole modeling of dynamics within sixty-year cycles of reference points and substantiated reasons for the population inversion and singular states in the dynamics of the pole

  11. Process Model of Quality Cost Monitoring for Small and Medium Wood-Processing Enterprises

    Directory of Open Access Journals (Sweden)

    Denis Jelačić

    2016-01-01

    Full Text Available Quality is not only a technical category and the system of quality management is not only focused on product quality. Quality and costs are closely interlinked. The paper deals with the quality cost monitoring in small and medium wood-processing enterprises (SMEs in Slovakia, and also presents the results of the questionnaire survey. An empirical study is aimed to determine the level of understanding and level of implementation of quality cost monitoring in wood-processing SMEs in Slovakia. The research is based on PAF model. A suitable model for quality cost monitoring is also proposed in the paper based on the research results with guidelines for using the methods of Activity Basic Costing. The empirical study is focused on SMEs, which make 99.8 % of all companies in the branch, and where the quality cost monitoring often works as a latent management subsystem. SMEs managers use indicators for monitoring the processe performance and production quality, but they usually do not develop a separate framework for measuring and evaluating quality costs.

  12. Generalized additive models reveal the intrinsic complexity of wood formation dynamics.

    Science.gov (United States)

    Cuny, Henri E; Rathgeber, Cyrille B K; Kiessé, Tristan Senga; Hartmann, Felix P; Barbeito, Ignacio; Fournier, Meriem

    2013-04-01

    The intra-annual dynamics of wood formation, which involves the passage of newly produced cells through three successive differentiation phases (division, enlargement, and wall thickening) to reach the final functional mature state, has traditionally been described in conifers as three delayed bell-shaped curves followed by an S-shaped curve. Here the classical view represented by the 'Gompertz function (GF) approach' was challenged using two novel approaches based on parametric generalized linear models (GLMs) and 'data-driven' generalized additive models (GAMs). These three approaches (GFs, GLMs, and GAMs) were used to describe seasonal changes in cell numbers in each of the xylem differentiation phases and to calculate the timing of cell development in three conifer species [Picea abies (L.), Pinus sylvestris L., and Abies alba Mill.]. GAMs outperformed GFs and GLMs in describing intra-annual wood formation dynamics, showing two left-skewed bell-shaped curves for division and enlargement, and a right-skewed bimodal curve for thickening. Cell residence times progressively decreased through the season for enlargement, whilst increasing late but rapidly for thickening. These patterns match changes in cell anatomical features within a tree ring, which allows the separation of earlywood and latewood into two distinct cell populations. A novel statistical approach is presented which renews our understanding of xylogenesis, a dynamic biological process in which the rate of cell production interplays with cell residence times in each developmental phase to create complex seasonal patterns.

  13. Lower pole stones

    DEFF Research Database (Denmark)

    Sanguedolce, Francesco; Breda, Alberto; Millan, Felix

    2013-01-01

    PURPOSE: To assess efficacy and safety of prone- and supine percutaneous nephrolithotomy (PCNL) for the treatment of lower pole kidney stones. METHODS: Data from patients affected by lower pole kidney stones and treated with PCNL between December 2005 and August 2010 were collected retrospectivel...

  14. Wood for the trees

    Directory of Open Access Journals (Sweden)

    Rob Garbutt

    2013-10-01

    Full Text Available Our paper focuses on the materiality, cultural history and cultural relations of selected artworks in the exhibition Wood for the trees (Lismore Regional Gallery, New South Wales, Australia, 10 June – 17 July 2011. The title of the exhibition, intentionally misreading the aphorism “Can’t see the wood for the trees”, by reading the wood for the resource rather than the collective wood[s], implies conservation, preservation, and the need for sustaining the originating resource. These ideas have particular resonance on the NSW far north coast, a region once rich in rainforest. While the Indigenous population had sustainable practices of forest and land management, the colonists deployed felling and harvesting in order to convert the value of the local, abundant rainforest trees into high-value timber. By the late twentieth century, however, a new wave of settlers launched a protest movements against the proposed logging of remnant rainforest at Terania Creek and elsewhere in the region. Wood for the trees, curated by Gallery Director Brett Adlington, plays on this dynamic relationship between wood, trees and people. We discuss the way selected artworks give expression to the themes or concepts of productive labour, nature and culture, conservation and sustainability, and memory. The artworks include Watjinbuy Marrawilil’s (1980 Carved ancestral figure ceremonial pole, Elizabeth Stops’ (2009/10 Explorations into colonisation, Hossein Valamanesh’s (2008 Memory stick, and AñA Wojak’s (2008 Unread book (in a forgotten language. Our art writing on the works, a practice informed by Bal (2002, Muecke (2008 and Papastergiadis (2004, becomes a conversation between the works and the themes or concepts. As a form of material excess of the most productive kind (Grosz, 2008, p. 7, art seeds a response to that which is in the air waiting to be said of the past, present and future.

  15. A Comparative Analysis of the New Five-Pole and Three-Pole Active Magnet Bearing

    Directory of Open Access Journals (Sweden)

    Pedram Vakili

    2012-07-01

    Full Text Available In recent years, more attention has been given to the active AMBs thanks to their low maintenance cost, suitability for clean environments, and high speed. One of the popular types of AMBs is the three-pole type with integrated and separate cores. Some deficiencies of this type of bearing are its high oscillation, low stability and low efficiency. This paper seeks to analyse the three-pole AMBs and describe their deficiencies and introduce and analyse a new five-pole AMB. The model thus proposed has lower oscillation as well as more stability and efficiency. The five-pole AMB has been simulated by a controller in the presence of disturbance. The results of simulation demonstrate lower vibration and oscillation in the five-pole AMB in comparison with the three-pole model.

  16. Discussion on the Construction of Regional Logistics Growth Pole Model%浅谈区域物流增长极模型的构建

    Institute of Scientific and Technical Information of China (English)

    王娟; 刘勤兰; 李钧

    2011-01-01

    以区域物流及区域经济的理论为基础,具体阐述了区域物流、区域物流中心及区域经济非均衡发展理论——增长极理论,并将其结合提出了增长极物流的概念。区域发展的增长极物流就是在区域内选取经济发展、物流发展及资源禀赋力强的地区作为物流发展的极点城市,对该地区加大发展力度并辐射区域内其余城市,从而带动整个区域物流的发展。最后,在该理论提出的基础上,选取不同评价指标构建了区域物流增长极模型并对其进行诠释以期对区域物流增长极的选取及发展方向提供依据。%Based on the regional logistics and regional economic theory as the foundation,this paper elaborated the specific regional logistics,regional logistics center and the unbalanced regional economic development theory——the theory of growth pole,and the combination of the growth pole of logistics concept.The growth pole of regional development in the area of logistics is the selection of economic development,logistics development and resource endowment and strong area as the city logistics development pole,to this area to increase development strength and radiation area remaining city,thus boosting the development of the regional logistics.Finally,this paper puts forward the theory basis,select the different evaluation index construction of the growth pole of regional logistics model and carries on the explanation to regional logistics growth pole selection and development to provide a basis for the direction.

  17. Kinetic model for torrefaction of wood chips in a pilot-scale continuous reactor

    DEFF Research Database (Denmark)

    Shang, Lei; Ahrenfeldt, Jesper; Holm, Jens Kai

    2014-01-01

    accordance with the model data. In an additional step a continuous, pilot scale reactor was built to produce torrefied wood chips in large quantities. The "two-step reaction in series" model was applied to predict the mass yield of the torrefaction reaction. Parameters used for the calculation were......Torrefaction is a mild thermal treatment (200-300 °C) in an inert atmosphere, known to increase the energy density of biomass by evaporation of water and a proportion of the volatiles. In this work a "two-step reaction in series" model was used to describe the thermal degradation kinetics of pine...... the temperature along the reactor and the biomass feeding rate in combination with the kinetic parameters obtained from the tests in the TGA. Together with results from a laboratory scale, batch torrefaction reactor that was used to determine the higher heating value (HHV) and mass loss (y) of the same material...

  18. Wood-feeding cockroaches as models for termite evolution (Insecta: Dictyoptera): Cryptocercus vs. Parasphaeria boleiriana.

    Science.gov (United States)

    Klass, Klaus-Dieter; Nalepa, Christine; Lo, Nathan

    2008-03-01

    Isoptera are highly specialized cockroaches and are one of the few eusocial insect lineages. Cryptocercus cockroaches have appeared to many as ideal models for inference on the early evolution of termites, due to their possible phylogenetic relationship and several shared key attributes in life history. Recently, Pellens, Grandcolas, and colleagues have proposed the blaberid cockroach Parasphaeria boleiriana to be an alternative model for the early evolution in termites. We compare the usefulness of Cryptocercus and P. boleiriana as models for termite evolution. Cryptocercus and lower Isoptera (1) can both feed on comparatively recalcitrant wood, (2) have an obligate, rich and unique hypermastigid and oxymonadid fauna in the hindgut, (3) transfer these flagellates to the next generation by anal trophallaxis, (4) have social systems that involve long-lasting biparental care, and, finally, (5) are strongly suggested to be sister groups, so that the key attributes (1)-(4) appear to be homologous between the two taxa. On the other hand, P. boleiriana (1) feeds on soft, ephemeral wood sources, (2) shows no trace of the oxymonadid and hypermastigid hindgut fauna unique to Cryptocercus and lower Isoptera, nor does it have any other demonstrated obligate relationship with hindgut flagellates, (3) is likely to lack anal trophallaxis, (4) has only a short period of uniparental brood care, and (5) is phylogenetically remote from the Cryptocercus+Isoptera clade. These facts would argue against any reasonable usage of P. boleiriana as a model for the early evolution of Isoptera or even of the clade Cryptocercus+Isoptera. Cryptocercus thus remains an appropriate model-taxon-by-homology for early termite evolution. As compared to P. boleiriana, some other Blaberidae (such as the Panesthiinae Salganea) appear more useful as model-taxa-by-homoplasy for the early evolution of the Cryptocercus+Isoptera clade, as their brooding behavior is more elaborate than in P. boleiriana.

  19. 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

  20. Linking fish and fluid behavior: Results from a physical model of turbulence and bioenergetics around large wood in rivers

    Science.gov (United States)

    Tullos, D. D.; Walter, C.

    2013-12-01

    The re-introduction of large woody debris into streams and rivers for restoration purposes is rapidly growing, yet detailed, quantitative study linking the hydraulics around and fish use of large wood is lacking. This presentation summarizes the methods and results of a 1:1 scale physical model of a meander and a full channel jam, including observations of the flow field and fish behavior around the wood. Velocity measurements were made with an array of ADVs at 0.1m spacing. The flow field was analyzed to map hydraulic regions around the wood and characterize the location, circulation patterns, turbulent length scales, and turbulence intensities of dominant flow structures. Underwater videogrammetry was conducted using wild, juvenile steelhead and coho to 1) identify patches of salmonid use of the wood, 2) establish orientation of the fish relative to the flow field, 3) document tailbeat frequencies and focal point velocities, and 4) investigate the percent of time fish expend avoiding predation, foraging, and resting in regions of hydraulic refuge under and around the wood. Results indicate that four primary flow fields develop. In the first, flow is concentrated in a jet through the wood structure, where downstream velocities, turbulence intensities, and total energy are highest. Downstream of the wood, flow expansion results in three hydraulic regions, characterized by a) a large eddy of length scale equivalent to approximately one-half of the wetted channel width, b) a lower velocity, downstream oriented core, and c) an interface of strong hydraulic gradients between the eddy and downstream flow. Fish were predominantly observed in two locations. As expected, fish generally avoided the jet directly, but were observed seeking cover under a log located in an area of rapid flow on the downstream portion of the jet. The fish were also observed hiding and resting in the eddy downstream of the log, with little to no evidence of the expected movement into higher

  1. Mathematical Modeling for the Development of Equipment for Thermochemical Processing of Wood Waste in to Dimethyl Ether

    Science.gov (United States)

    Sadrtdinov, Almaz R.; Esmagilova, Liliya M.; Saldaev, Vladimir A.; Sattarova, Zulfiya G.; Mokhovikov, Alexey A.

    2016-08-01

    The paper describes the process of thermochemical wood waste processing in to dimethyl ether. The physical picture of the process of waste wood recycling was compiled and studied and the mathematical model in the form of differential and algebraic equations with initial and boundary conditions was developed on its basis. The mathematical model allows to determine the optimum operating parameters of synthesis gas producing process, suitable for the catalytic synthesis of dimethyl ether and to calculate the basic constructive parameters of the equipment flowsheet.

  2. A model for the prediction of the thermal degradation and ignition of wood under constant and variable heat flux

    Energy Technology Data Exchange (ETDEWEB)

    Bilbao, Rafael; Mastral, Jose F.; Ceamanos, Jesus; Aldea, Maria E.; Betran, Monica [Department of Chemical and Environmental Engineering, Faculty of Sciences,University of Zaragoza, Pedro Cerbuna 12, Zaragoza (Spain); Lana, Jose A. [Direction of Technology and Environment, Enagas-Gas Natural, Crta. Madrid, Zaragoza (Spain)

    2002-01-01

    The ignition of combustible materials is an important aspect of the processes taking place in an unwanted fire. In this work, an experimental and theoretical study of the ignition process of wood has been carried out. Experiments of both spontaneous and piloted ignition have been performed. Constant and decreasing variable heat fluxes have been tested. A mathematical model has been used to predict the time to ignition of wood for the different operating conditions used. The solution of the model provides the temperature at each point of the solid, the local solid conversion and the time to ignition of the material. In general, a good agreement between experimental and theoretical results is obtained.

  3. Thermal degradations of wood biofuels, coals and hydrolysis lignin from the Russian Federation: Experiments and modeling.

    Science.gov (United States)

    Popova, Evgeniya; Chernov, Aleksandr; Maryandyshev, Pavel; Brillard, Alain; Kehrli, Damaris; Trouvé, Gwenaëlle; Lyubov, Viktor; Brilhac, Jean-François

    2016-10-01

    The thermal degradation of wood biofuels (spruce, pine), of coals from different fields of the Russian Federation and of hydrolysis lignin is investigated using a thermogravimetric analyzer under different heating conditions and under non-oxidative or oxidative atmospheres. The samples are indeed submitted to a linear temperature ramp of 10K/min or to a temperature ramp of 200K/min up to a residence temperature between 250 and 450°C where they are maintained during 4h (isothermal conditions). The values of the kinetic parameters are determined for these different samples in both thermal conditions, either using the differential isoconversional method or by means of an Extended Independent Parallel Reaction (EIPR) model. The values of the kinetic parameters obtained with this EIPR model for spruce trunk are also compared with that of its main constituents (hemicellulose, cellulose and lignin). Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Finite element analysis of boron diffusion in wooden Poles

    DEFF Research Database (Denmark)

    Krabbenhøft, Kristian; Hoffmeyer, Preben; Bechgaard, Carl;

    2004-01-01

    The problem of describing the migration of dissolved boron in wood is treated with special reference to the commonly used remedial treatment of wooden poles. The governing equations are derived and discussed together with some of the material parameters required. The equations are solved by the f...... by the finite element method and, finally, results showing the effect of different treatment strategies are presented....

  5. Finite Element Analysis of Boron Diffusion in Wooden Poles

    DEFF Research Database (Denmark)

    Krabbenhøft, Kristian; Hoffmeyer, Preben; Bechgaard, Carl;

    2004-01-01

    The problem of describing the migration of dissolved boron in wood is treated with special reference to the commonly used remedial treatment of wooden poles. The governing equations are derived and discussed together with some of the material parameters required. The equations are solved by the f...... by the finite element method and, finally, results showing the effect of different treatment strategies are presented....

  6. Finite Element Analysis of Boron Diffusion in Wooden Poles

    DEFF Research Database (Denmark)

    Krabbenhøft, Kristian; Hoffmeyer, P.; Bechgaard, C.;

    2003-01-01

    The problem of describing the migration of dissolved boron in wood is treated with special reference to the commonly used remedial treatment of wooden poles. The governing equations are derived and discussed together with some of the material parameters required. The equations are solved by the f...... by the finite element method and, finally, results showing the effect of different treatment strategies are presented....

  7. Modeling of off-gas emissions from wood pellets during marine transportation.

    Science.gov (United States)

    Pa, Ann; Bi, Xiaotao T

    2010-10-01

    After a fatal accident during the discharge of wood pellets at Helsingborg, emissions from pellets during marine transportation became a concern for the safe handling and storage of wood pellets. In this paper, a two-compartment model has been developed for the first time to predict the concentrations of CO, CO₂, CH₄, and O₂ inside the cargo ship and the time and rate of forced ventilation required before the safe entry into the stairway adjacent to the storage hatch. The hatch and stairway are treated as two perfectly mixed tanks. The gas exchange rate between these two rooms and the gas exchange rate with the atmosphere are fitted to satisfy a measured tracer final concentration of 33 p.p.m.v. in the stairway and an average final hatch to stairway CO, CO₂, and CH₄ concentration ratio of 1.62 based on measurement from five other hatch and stairway systems. The reaction kinetics obtained from a laboratory unit using a different batch of pellets, however, need to be scaled in order to bring the prediction to close agreement with onboard measured emission data at the end of voyage. Using the adjusted kinetic data, the model was able to predict the general trend of data recorded in the first 12.5 days of the voyage. Further validation, however, requires the data recorded over the whole journey. The model was applied to predict the effect of ocean temperature on the off-gas emissions and the buildup of concentrations in the hatch and stairway. For safe entry to the cargo ship, the current model predicted that a minimal ventilation rate of 4.4 hr⁻¹ is required for the stairway's CO concentration to lower to a safe concentration of 25 p.p.m.v. At 4.4 hr⁻¹, 10 min of ventilation time is required for the safe entry into the stairway studied.

  8. 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).

  9. 2D Stabilised analytic signal method in DC pole-pole potential data interpretation

    Indian Academy of Sciences (India)

    Paras R Pujari; Rambhatla G Sastry

    2003-03-01

    Using analytic signal method, interpretation of pole-pole secondary electric potentials due to 2D conductive/resistive prisms is presented. The estimated parameters are the location, lateral extent or width and depth to top surface of the prism. Forward modelling is attempted by 2D-Finite Difference method. The proposed stabilised analytic signal algorithm (RES2AS) uses Tikhonov's regularization scheme and FFT routines. The algorithm is tested on three theoretical examples and field data from the campus of Roorkee University. The stability of RES2AS is also tested on synthetic error prone secondary pole-pole potential data.

  10. Enrichment with wood blocks does not affect toxicity assessment in an exploratory toxicology model using Sprague-Dawley rats.

    Science.gov (United States)

    Ditewig, Amy C; Bratcher, Natalie A; Davila, Donna R; Dayton, Brian D; Ebert, Paige; Lesuisse, Philippe; Liguori, Michael J; Wetter, Jill M; Yang, Hyuna; Buck, Wayne R

    2014-05-01

    Environmental enrichment in rodents may improve animal well-being but can affect neurologic development, immune system function, and aging. We tested the hypothesis that wood block enrichment affects the interpretation of traditional and transcriptomic endpoints in an exploratory toxicology testing model using a well-characterized reference compound, cyclophosphamide. ANOVA was performed to distinguish effects of wood block enrichment separate from effects of 40 mg/kg cyclophosphamide treatment. Biologically relevant and statistically significant effects of wood block enrichment occurred only for body weight gain. ANOVA demonstrated the expected effects of cyclophosphamide on food consumption, spleen weight, and hematology. According to transcriptomic endpoints, cyclophosphamide induced fewer changes in gene expression in liver than in spleen. Splenic transcriptomic pathways affected by cyclophosphamide included: iron hemostasis; vascular tissue angiotensin system; hepatic stellate cell activation and fibrosis; complement activation; TGFβ-induced hypertrophy and fibrosis; monocytes, macrophages, and atherosclerosis; and platelet activation. Changes in these pathways due to cyclophosphamide treatment were consistent with bone marrow toxicity regardless of enrichment. In a second study, neither enrichment nor type of cage flooring altered body weight or food consumption over a 28-d period after the first week. In conclusion, wood block enrichment did not interfere with a typical exploratory toxicology study; the effects of ingested wood on drug level kinetics may require further consideration.

  11. Modeling transcriptional networks regulating secondary growth and wood formation in forest trees.

    Science.gov (United States)

    Liu, Lijun; Filkov, Vladimir; Groover, Andrew

    2014-06-01

    The complex interactions among the genes that underlie a biological process can be modeled and presented as a transcriptional network, in which genes (nodes) and their interactions (edges) are shown in a graphical form similar to a wiring diagram. A large number of genes have been identified that are expressed during the radial woody growth of tree stems (secondary growth), but a comprehensive understanding of how these genes interact to influence woody growth is currently lacking. Modeling transcriptional networks has recently been made tractable by next-generation sequencing-based technologies that can comprehensively catalog gene expression and transcription factor-binding genome-wide, but has not yet been extensively applied to undomesticated tree species or woody growth. Here we discuss basic features of transcriptional networks, approaches for modeling biological networks, and examples of biological network models developed for forest trees to date. We discuss how transcriptional network research is being developed in the model forest tree genus, Populus, and how this research area can be further developed and applied. Transcriptional network models for forest tree secondary growth and wood formation could ultimately provide new predictive models to accelerate hypothesis-driven research and develop new breeding applications.

  12. VT Green Mountain Power Pole Data

    Data.gov (United States)

    Vermont Center for Geographic Information — (Link to Metadata) Green Mountain Power (GMP) pole and OVERHEAD linear distribution/sub-transmission model data. THE LINEAR DISTRIBUTION LAYER ONLY INCLUDES OVERHEAD...

  13. Source emission and model evaluation of formaldehyde from composite and solid wood furniture in a full-scale chamber

    Science.gov (United States)

    This paper describes the measurement and model evaluation of formaldehyde source emissions from composite and solid wood furniture in a full-scale chamber under dynamic conditions using ASTM D 6670-01 (2007). Four brands of the same type furniture product were tested. The data we...

  14. Self Assembly and Pyroelectric Poling for Organics

    Science.gov (United States)

    2015-07-06

    ozone or nitrogen oxides) and energetic species from corona discharge . These problems can strongly inhibit the efficient poling and large-scale...respectively. In this idealized model , a modest temperature change (10 to 50 °C) will lead to a considerably large electrostatic field in a thin film dielectric...measurement); (e) contact poling. 4. Systematically analyze electrostatics models to quantify electric field generation from commonly used pyroelectric

  15. Wood-based Tri-Axial Sandwich Composite Materials: Design, Fabrication, Testing, Modeling and Application

    Science.gov (United States)

    Jinghao Li; John F. Hunt; Shaoqin Gong; Zhiyong Cai

    2014-01-01

    As the demand for sustainable materials increases, there are unique challenges and opportunities to develop light-weight green composites materials for a wide range of applications. Thus wood-based composite materials from renewable forests may provide options for some niche applications while helping to protect our environment. In this paper, the wood-based tri-axial...

  16. Fracture mechanics and statistical modeling of ternary blends of polylactide/ethylene-acrylate copolymer /wood-flour composites

    Science.gov (United States)

    Afrifah, Kojo Agyapong

    This study examined the mechanisms of toughening the brittle bio-based poly(lactic acid) (PLA) with a biodegradable rubbery impact modifier to develop biodegradable and cost effective PLA/wood-flour composites with improved impact strength, toughness, high ductility, and flexibility. Semicrystalline and amorphous PLA grades were impact modified by melt blending with an ethylene-acrylate copolymer (EAC) impact modifier. EAC content was varied to study the effectiveness and efficiency of the impact modifier in toughening the semicrystalline and amorphous grades of the PLA. Impact strength was used to assess the effectiveness and efficiency of the EAC in toughening the blends, whereas the toughening mechanisms were determined with the phase morphologies and the miscibilities of the blends. Subsequent tensile property analyses were performed on the most efficiently toughened PLA grade. Composites were made from PLA, wood flour of various particle sizes, and EAC. Using two-level factorial design the interaction between wood flour content, wood flour particle size, and EAC content and its effect on the mechanical properties of the PLA/wood-flour composites was statistically studied. Numerical optimization was also performed to statistically model and optimize material compositions to attain mechanical properties for the PLA/wood-flour composites equivalent to at least those of unfilled PLA. The J-integral method of fracture mechanics was applied to assess the crack initiation (Jin) and complete fracture (J f) energies of the composites to account for imperfections in the composites and generate data useful for engineering designs. Morphologies of the fractured surfaces of the composites were analyzed to elucidate the failure and toughening mechanisms of the composites. The EAC impact modifier effectively improved the impact strength of the PLA/EAC blends, regardless of the PLA type. However, the EAC was more efficient in the semicrystalline grades of PLA compared to the

  17. 基于GPS信号和Klobuchar电离层模型反演地磁北极%INVERSING GEOMAGNETIC NORTH POLE BASED ON GPS SIGNAL AND KLOBUCHAR MODEL

    Institute of Scientific and Technical Information of China (English)

    郭英; 程鹏飞; 吕洪标

    2011-01-01

    基于地磁对电离层的影响,尝试利用GPS信号和Klobuchchar模型估计地磁北极在地理坐标系中的位置,并建立了相应的数学模型.理论分析和数据验证了方法的可行性,如果进行Klobuchar模型的区域化改进和算法的完善,将更有利于地磁北极估计的可靠性和估计精度的提高.%On the basis of the influence of geomagnetic field on ionosphere, the position of geomagnetic north pole in geographic coordinates was estimated by using GPS signal and Klobuchar model, and the corresponding mathematical model was established. This method is validated to be feasible by theoretical analysis and simulated data, and it is further summarized that the regionalized improved Klobuchar model and perfect arithmetic will be in favor of the precision and reliability of estimating geomagnetic north pole.

  18. Development of a pathway model to assess the exposure of European pine trees to pine wood nematode via the trade of wood

    NARCIS (Netherlands)

    Douma, J.C.; Werf, Van Der W.; Hemerik, L.; Magnusson, C.; Robinet, C.

    2017-01-01

    Pine wood nematode (PWN), Bursaphelenchus xylophilus, is a threat for pine species (Pinus spp.) throughout the world. The nematode is native to North America, and invaded Japan, China, Korea, and Taiwan, and more recently Portugal and Spain. PWN enters new areas through trade in wood products. Once

  19. pi. /sup -/p-italic. --> pi. /sup o-italic/n-italic scattering at high energies and a comparison of pole-plus-cut and odderon models

    Energy Technology Data Exchange (ETDEWEB)

    Fazel-e-Aleem; Saleem, M.

    1985-11-01

    The data on the differential cross section and polarization for the reaction ..pi../sup -/p-italic..--> pi../sup o-italic/n-italic and on ..delta..sigma = sigma/sub t//sub o//sub t/(..pi../sup -/p-italic) : sigma/sub t//sub o//sub t/ (..pi../sup +/p-italic) are not precise enough to distinguish between the conventional pole-plus-cut model and the unconventional model based on the maximal odderon asymptotic behavior. The amplitude analysis performed by using both the models also gives results which are consistent with those obtained from the experimental data. It is shown that the measurements of differential cross section and polarization at 400 GeV/c and 100 GeV/c or above, respectively, will be decisive in determining the validity of either of these models.

  20. Characteristics and modeling of spruce wood under dynamic compression load; Charakteristik und Modellierung von Fichtenholz unter dynamischer Druckbelastung

    Energy Technology Data Exchange (ETDEWEB)

    Eisenacher, Germar

    2014-01-28

    Spruce wood is frequently used as an energy absorbing material in impact limiters of packages for the transportation of radioactive material. A 9m drop test onto an unyielding target is mandatory for the packages. The impact results in a dynamic compression load of the spruce wood inside the impact limiter. The lateral dilation of the wood is restrained thereby due to encasing steel sheets. This work's objective was to provide a material model for spruce wood based on experimental investigations to enable the calculation of such loading conditions. About 600 crush tests with cubical spruce wood specimens were performed to characterize the material. The compression was up to 70% and the material was assumed to be transversely isotropic. Particularly the lateral constraint showed to have an important effect: the material develops a high lateral dilation without lateral constraint. The force-displacement characteristics show a comparably low force level and no or only slight hardening. Distinctive softening occurs after the linear-elastic region when loaded parallel to the fiber. On the other hand, using a lateral constraint results in significantly higher general force levels, distinctive hardening and lateral forces. The softening effect when loaded parallel to the fiber is less distinctive. Strain rate and temperature raise or lower the strength level, which was quantified for the applicable ranges of impact limiters. The hypothesis of an uncoupled evolution of the yield surface was proposed based on the experimental findings. It postulates an independent strength evolution with deviatoric and volumetric deformation. The hypothesis could be established using the first modeling approach, the modified LS-DYNA material model MAT075. A transversely isotropic material model was developed based thereupon and implemented in LS-DYNA. The material characteristics of spruce wood were considered using a multi-surface yield criterion and a non-associated flow rule. The

  1. 3D hierarchical computational model of wood as a cellular material with fibril reinforced, heterogeneous multiple layers

    DEFF Research Database (Denmark)

    Qing, Hai; Mishnaevsky, Leon

    2009-01-01

    A 3D hierarchical computational model of deformation and stiffness of wood, which takes into account the structures of wood at several scale levels (cellularity, multilayered nature of cell walls, composite-like structures of the wall layers) is developed. At the mesoscale, the softwood cell...... is presented as a 3D hexagon-shape-tube with multilayered walls. The layers in the softwood cell are considered as considered as composite reinforced by microfibrils (celluloses). The elastic properties of the layers are determined with Halpin–Tsai equations, and introduced into mesoscale finite element...... cellular model. With the use of the developed hierarchical model, the influence of the microstructure, including microfibril angles (MFAs, which characterizes the orientation of the cellulose fibrils with respect to the cell axis), the thickness of the cell wall, the shape of the cell cross...

  2. Modeling the time-dependent flexural response of wood-plastic composite materials

    Science.gov (United States)

    Hamel, Scott E.

    Wood-plastic composites (WPCs) are moisture sensitive bimodal anisotropic nonlinear viscoelastic materials, with time and temperature having the greatest effect on mechanical behavior. As WPC producers seek to manufacture structural bending members, such as beams and joists, it is important that the material's time and temperature-dependent mechanical behavior be understood and characterized. The complicated time-dependent behavior means that WPC bending deflections cannot be adequately predicted for even practical design purposes using simple linear-elastic models. Instead, mechanics-based models that incorporate the observed time-dependent and nonlinear responses are necessary. This dissertation presents an experimental and modeling program used to test and characterize the axial and shear behaviors of seven different WPC products (primarily polyethylene and polypropylene) subjected to both quasi-static and creep loading at multiple temperatures. These data were used to develop a mechanics based model that can predict bending deflections of complex sections at any time or temperature. Additionally, a practical design method and standardized test procedures were created for use in typical long-term bending situations. A mechanical model for WPCs must combine time-dependent material characterization with a tool that can simulate mode dependence, temperature dependence, changing neutral axis location, and nonlinear axial stress distributions that vary over the length of a member and evolve with time. Finite-element (FE) modeling was chosen as the most practical way to satisfy these requirements. The model developed in this study uses an FE model with a custom-designed material model. Bending deflection predictions from the model were compared to experimental testing and the model showed some success despite the difficulties created by the material variability. The practical method created for designing WPC structural bending members utilizes four material constants

  3. Assessing wood-based synthetic natural gas technologies using the SWISS-MARKAL model

    Energy Technology Data Exchange (ETDEWEB)

    Schulz, Thorsten F.; Barreto, Leonardo; Kypreos, Socrates [Paul Scherrer Institute, Villigen PSI (Switzerland). Energy Economics Group; Stucki, Samuel [Paul Scherrer Institute, Villigen PSI (Switzerland). General Energy

    2007-10-15

    In future, new biomass technologies can gain significant importance in the Swiss energy sector. Therefore, this paper assesses the economic conditions under which new biomass technologies become competitive. The focus of this assessment is on the production of synthetic natural gas (bio-SNG) from wood in a methanation plant. The assessment is conducted with the cost-optimization model SWISS-MARKAL (MARKet ALlocation). SWISS-MARKAL projects future technology investments and provides an integrated analysis of primary, secondary, final and end-use energy in Switzerland. In addition to a reference scenario, the effects of increasing oil and gas prices, the effects of allocating subsidies to the methanation plant and the effects of competition between the methanation plant and a biomass-based Fischer-Tropsch (FT) synthesis are evaluated. Moreover, a sensitivity analysis is performed by varying investment costs of the methanation plant. The results are in favour of bio-SNG in the transportation sector where the synergetic use of bio-SNG and natural gas reduces the dependence on oil imports and the level of CO{sub 2} emissions. (author)

  4. Response of pine forest to disturbance of pine wood nematode with interpretative structural model

    Institute of Scientific and Technical Information of China (English)

    Juan SHI; Youqing LUO; Xiaosu YAN; Weiping CHEN; Ping JIANG

    2009-01-01

    Pine wood nematode (PWN, Bursaphelenchus xylophilus), originating from North America, causes destructive pine wilt disease. Different pine forest ecosystems have different resistances to B. xylophilus,and after its invasion, the resilience and restoration direction of different ecosystems also varies. In this study, an interpretative structural model was applied for analyzing the response of pine forest ecosystem to PWN disturbance. The result showed that a five-degree multi-stage hierarchical system affected the response of the pine forest ecosystem to PWN disturbance, in which direct affecting factors are resistance and resilience. Furthermore,the analysis to the 2nd, 3rd and 4th degree factors showed that not only does distribution pattern of plant species and pine's ecological features affect the resistance of pine forests' ecosystem, but removal of attacked trees and other measures also influence the resistance through indirectly affecting the damage degree of Monochamus alternatus and distribution pattern of plant species. As for resilience,it is influenced directly by soil factors, hydrology,surrounding species provenance and biological character-istics of the second and jointly dominant species, and the climate factors can also have a direct or indirect effect on it by affecting the above factors. Among the fifth elements,the elevation, gradient and slope direction, topographical factors, diversity of geographical location and improve-ment of prevention technology all influence the response of pine forest ecosystem to PWN disturbance.

  5. A moving-barber-pole illusion.

    Science.gov (United States)

    Sun, Peng; Chubb, Charles; Sperling, George

    2014-05-01

    In the barber-pole illusion (BPI), a diagonally moving grating is perceived as moving vertically because of the shape of the vertically oriented window through which it is viewed-a strong shape-motion interaction. We introduce a novel stimulus-the moving barber pole-in which a diagonal, drifting sinusoidal carrier is windowed by a raised, vertical, drifting sinusoidal modulator that moves independently of the carrier. In foveal vision, the moving-barber-pole stimulus can be perceived as several active barber poles drifting horizontally but also as other complex dynamic patterns. In peripheral vision, pure vertical motion (the moving-barber-pole illusion [MBPI]) is perceived for a wide range of conditions. In foveal vision, the MBPI is observed, but only when the higher-order modulator motion is masked. Theories to explain the BPI make indiscriminable predictions in a standard barber-pole display. But, in moving-barber-pole stimuli, the motion directions of features (e.g., end stops) of the first-order carrier and of the higher-order modulator are all different from the MBPI. High temporal frequency stimuli viewed peripherally greatly reduce the effectiveness of higher-order motion mechanisms and, ideally, isolate a single mechanism responsible for the MBPI. A three-stage motion-path integration mechanism that (a) computes local motion energies, (b) integrates them for a limited time period along various spatial paths, and (c) selects the path with the greatest motion energy, quantitatively accounts for these high-frequency data. The MBPI model also accounts for the perceived motion-direction in peripherally viewed moving-barber-pole stimuli that do and do not exhibit the MBPI over the entire range of modulator (0-10 Hz) and carrier (2.5-10 Hz) temporal frequencies tested.

  6. SIMULATION OF EARTH'S POLES DYNAMICS USING ASK-ANALYSIS

    Directory of Open Access Journals (Sweden)

    Cherednychenko N. A.

    2014-05-01

    Full Text Available Based on local semantic information models, we have examined the dependence of the dynamics of the displacement of the pole positions of celestial objects. We have also developed and differentiated an analysis of ASK-pole modeling of dynamics within sixty-year cycles of reference points and substantiated reasons for the population inversion and singular states in the dynamics of the pole

  7. Generalized Pole Inflation: Hilltop, Natural, and Chaotic Inflationary Attractors

    CERN Document Server

    Terada, Takahiro

    2016-01-01

    A new paradigm for inflationary model building appeared recently, in which inflationary observables are determined by the structure of a pole in the inflaton kinetic term rather than the shape of the inflaton potential. We comprehensively study this framework with an arbitrary order of the pole taking into account possible additional poles in the kinetic term or in the potential. Depending on the setup, the canonical potential becomes the form of hilltop or plateau models, variants of natural inflation, or monomial or polynomial chaotic inflation. We demonstrate attractor behavior of these models and compute corrections from the additional poles to the inflationary observables.

  8. Diphotons at the Z-pole in models of the 750 GeV resonance decaying to axion-like particles

    Science.gov (United States)

    Alves, Alexandre; Dias, Alex G.; Sinha, Kuver

    2016-08-01

    Models in which the 750 GeV resonance ( S) decays to two light axion-like particles (ALPs a), which in turn decay to collimated photons mimicking the observed signal, are motivated by Hidden Valley scenarios and could also provide a mechanism by which a S → γγ signal persists while S → Zγ , ZZ and W W remain subdued in the near future. We point out that these Hidden Valley like models invoking S → aa → 4γ must also contend with Z → a(→ γγ)γ constraints coming from CDF and ATLAS. Within an effective field theory framework, we work out the constraints on the couplings of S to a and gauge bosons coming from photonic Z decays and ensuring that the ALPs decay inside the electromagnetic calorimeter, in two regimes — where a decays primarily to photons, and where a also has hadronic branchings. The analysis is done for both when S has a large as well as a narrow width, and for different relative contributions to the signal coming from S → γγ and a → γγ. Results for the particular case where S and a belong to the same complex field are also presented. A γγ resonance at the Z-pole coming from Z → aγ is expected in this class of models. Taking benchmark ALP masses below around 0.4 GeV and, assuming reasonable values for the fake jet rate and the identification efficiency of the photon-jet, we find the prospects for the discovery of diphotons at the Z-pole.

  9. Fast Calculation Model and Theoretical Analysis of Rotor Unbalanced Magnetic Pull for Inter-Turn Short Circuit of Field Windings of Non-Salient Pole Generators

    Directory of Open Access Journals (Sweden)

    Guangtao Zhang

    2017-05-01

    Full Text Available Inter-turn short circuit of field windings (ISCFW may cause the field current of a generator to increase, output reactive power to decrease, and unit vibration to intensify, seriously affecting its safe and stable operation. Full integration of mechanical and electrical characteristics can improve the sensitivity of online monitoring, and detect the early embryonic period fault of small turns. This paper studies the calculations and variations of unbalanced magnetic pull (UMP, of which the excitation source of rotor vibration is the basis and key to online fault monitoring. In grid load operation, ISCFW are first calculated with the multi-loop method, so as to obtain the numerical solutions of the stator and the rotor currents during the fault. Next, the air-gap magnetic field of the ISCFW is analyzed according to the actual composition modes of the motor loops in the fault, so as to obtain the analytic expressions of the air-gap magnetic motive force (MMF and magnetic density. The UMP of the rotor is obtained by solving the integral of the Maxwell stress. The correctness of the electric quantity calculation is verified by the ISCFW experiment, conducted in a one pair-pole non-salient pole model machine. On this basis, comparing the simulation analysis with the calculation results of the model in this paper not only verifies the accuracy of the electromagnetic force calculation, but also proves that the latter has the advantages of a short time consumption and high efficiency. Finally, the influencing factors and variation law of UMP are analyzed by means of an analytic model. This develops a base for the online monitoring of ISCFW with the integration of mechanical and electrical information.

  10. Impact of different wood chip species (oak, acacia and cherry on evolution of individual anthocyanins, chromatic characteristics and antioxidant capacity in model wine solutions

    Directory of Open Access Journals (Sweden)

    Jordão António M.

    2017-01-01

    Full Text Available The aim of present work was to investigate the impact of different oak (Q. alba, Q. robur and Q. pyrenaica, acacia and cherry wood chips on evolution of individual anthocyanin content, chromatic characteristics and antioxidant capacity by the use of model wine solutions. According to the results obtained, model wine solutions containing acacia and especially cherry wood extracts showed more evident changes of individual anthocyanin composition, especially due to the formation of large number of new direct condensation anthocyanins, than model wines with oak extracts. These results were accompanied also by a higher color degradation and a lower antioxidant potential of solutions containing the different wood chip extract species, compared with solutions containing only anthocyanin alone. This research contributes to a better knowledge about the color evolution of red wines when they are aging in contact with new alternative wood species, especially acacia and cherry.

  11. Consequences of increasing bioenergy demand on wood and forests: An application of the Global Forest Products Model

    Science.gov (United States)

    Buongiorno, J.; Raunikar, R.; Zhu, S.

    2011-01-01

    The Global Forest Products Model (GFPM) was applied to project the consequences for the global forest sector of doubling the rate of growth of bioenergy demand relative to a base scenario, other drivers being maintained constant. The results showed that this would lead to the convergence of the price of fuelwood and industrial roundwood, raising the price of industrial roundwood by nearly 30% in 2030. The price of sawnwood and panels would be 15% higher. The price of paper would be 3% higher. Concurrently, the demand for all manufactured wood products would be lower in all countries, but the production would rise in countries with competitive advantage. The global value added in wood processing industries would be 1% lower in 2030. The forest stock would be 2% lower for the world and 4% lower for Asia. These effects varied substantially by country. ?? 2011 Department of Forest Economics, SLU Ume??, Sweden.

  12. Modeling of pyrolysis and combustion of large pine wood samples: comparison of different mechanisms of heat transfer

    Energy Technology Data Exchange (ETDEWEB)

    Bilbao, R.; Mastral, J.F.; Ceamanos, J.; Aldea, M.E. [University of Zaragoza (Spain)

    1997-07-01

    Pyrolysis and the combustion of wood have become very important in the production of electricity. For the optimum design of the equipment used in these processes, it is necessary to predict solid conversion under conditions as similar as possible to those observed in the actual process. Many have studied the thermal decomposition of wood. However, the prediction of solid conversion or temperature profiles when large particles and variable heat fluxes are used, has received far less attention. In order to predict these variables properly, different mechanisms of heat transfer over the sample were studied, including the convective cooling of the surface by the gases from the interior of the sample. A mathematical model includes decomposition kinetics, variable thermal properties and influence of the water content. For the validation of the model, thermal decomposition of large, slab-shaped pine wood samples under a radiant, variable heat flux with continuous measurements of solid weight loss and temperature at different points was performed. Theoretical and experimental results agree for most conditions. (author)

  13. Nanoscale in Wood, Nanowood and Wood-Inorganic Nanocomposites

    Institute of Scientific and Technical Information of China (English)

    Zhao Guangjie; Lu Wenhua

    2003-01-01

    In order to introduce nano science and technology (NST) into the research field of wood science and technology, andpromote the research of wood science and wood-inorganic composites to nanoscale, some new concepts, such as the nano space inwood, nano structure units of wood and nanowood are put forward in this paper based on the layer structure of wood cell wall and thepile-up model of its main components. Furthermore, the process of preparing nanowood is discussed, and wood-inorganic nanocom-posites may be operated in three ways with wood (matrix) and inorganic filler phase in 0-2, 0-3 or 2-3 dimensions respectively. Thefollowing results are obtained: (1) The nanoscale voids in wood indicate that wood has inherent space to accommodate nanosizedmaterials, such as nanoparticles, nanotubes and nanosticks; (2) According to the size from top down, the nano structure units in woodcan be classified as: nanolayers, nano CMF (cellulose microfibril) and matrix, nano crystallite units and cellulose chain clusters, andthese can theoretically form nanowood; (3) The preparation of wood-inorganic nanocomposites can be operated on 0-2, 0-3 or 2-3dimensions.

  14. Rad Pole Cam Development

    Energy Technology Data Exchange (ETDEWEB)

    Heckendorn, F. M.; Odell, D. M. C; Harpring, L. J.; Peterson, K. D.

    2005-10-05

    The RadPoleCam was developed to provide Department Of Energy (DOE) first responders the capability to assess the radiological and visual condition of remote or inaccessible locations. Real time gamma isotopic identification is provided to the first responder in the form of audio feedback (i.e. spoken through head phones) from a gamma detector mounted on a collapsible pole that can extend from 1 to 9 meters (6 to 29 feet). Simultaneously, selectable direct and side looking visual images are provided from the 5cm (2in) diameter, waterproof probe tip. The lightweight, self contained, ruggedized, system will provide a rapidly deployable field system for visual and radiological search and assessment of confined spaces and extended reach locations.

  15. Constraining gluon poles

    Directory of Open Access Journals (Sweden)

    I.V. Anikin

    2015-12-01

    Full Text Available In this letter, we revise the QED gauge invariance for the hadron tensor of Drell–Yan type processes with the transversely polarized hadron. We perform our analysis within the Feynman gauge for gluons and make a comparison with the results obtained within the light-cone gauge. We demonstrate that QED gauge invariance leads, first, to the need of a non-standard diagram and, second, to the absence of gluon poles in the correlators 〈ψ¯γ⊥A+ψ〉 related traditionally to dT(x,x/dx. As a result, these terms disappear from the final QED gauge invariant hadron tensor. We also verify the absence of such poles by analyzing the corresponding light-cone Dirac algebra.

  16. Wooded areas

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report summarizes the management of wooded areas on Neal Smith National Wildlife Refuge (formerly Walnut Creek National Wildlife Refuge) between 1992 and 2009.

  17. [Determination of the parameters for producing a biobinder from wood: a mathematical modeling of the transformation of lignocellulose substrate by the fungus Panus tigrinus].

    Science.gov (United States)

    Kondrashchenko, V I; Manukovskiĭ, N S; Kovalev, V S

    2006-01-01

    A biochemical scheme for the transformation of wood lignocellulose during enzymatic hydrolysis of polysaccharides and lignin destruction in reactions involving free radicals was developed, and a corresponding mathematical model was constructed. Processing (fermentation) of wood particles by the fungus Panus tigrinus in a submerged culture for producing a biobinder of wood composites--woodchip boards and fiber-boards--is considered. The mathematical model was used to study the technological parameters that influence the production of enzymes and fungal biomass and the level of free radical accumulation in the substrate, i.e., the factors determining the production of the biobinder. The optimal values of these parameters were determined, namely: the specific surface of wood particles, amounting to 2000 cm2/g; processing time of 56 h; and an initial concentration of 3.0 g/l of fungal biomass in the submerged culture.

  18. Strength development in concrete with wood ash blended cement and use of soft computing models to predict strength parameters

    Directory of Open Access Journals (Sweden)

    S. Chowdhury

    2015-11-01

    Full Text Available In this study, Wood Ash (WA prepared from the uncontrolled burning of the saw dust is evaluated for its suitability as partial cement replacement in conventional concrete. The saw dust has been acquired from a wood polishing unit. The physical, chemical and mineralogical characteristics of WA is presented and analyzed. The strength parameters (compressive strength, split tensile strength and flexural strength of concrete with blended WA cement are evaluated and studied. Two different water-to-binder ratio (0.4 and 0.45 and five different replacement percentages of WA (5%, 10%, 15%, 18% and 20% including control specimens for both water-to-cement ratio is considered. Results of compressive strength, split tensile strength and flexural strength showed that the strength properties of concrete mixture decreased marginally with increase in wood ash contents, but strength increased with later age. The XRD test results and chemical analysis of WA showed that it contains amorphous silica and thus can be used as cement replacing material. Through the analysis of results obtained in this study, it was concluded that WA could be blended with cement without adversely affecting the strength properties of concrete. Also using a new statistical theory of the Support Vector Machine (SVM, strength parameters were predicted by developing a suitable model and as a result, the application of soft computing in structural engineering has been successfully presented in this research paper.

  19. Strength development in concrete with wood ash blended cement and use of soft computing models to predict strength parameters.

    Science.gov (United States)

    Chowdhury, S; Maniar, A; Suganya, O M

    2015-11-01

    In this study, Wood Ash (WA) prepared from the uncontrolled burning of the saw dust is evaluated for its suitability as partial cement replacement in conventional concrete. The saw dust has been acquired from a wood polishing unit. The physical, chemical and mineralogical characteristics of WA is presented and analyzed. The strength parameters (compressive strength, split tensile strength and flexural strength) of concrete with blended WA cement are evaluated and studied. Two different water-to-binder ratio (0.4 and 0.45) and five different replacement percentages of WA (5%, 10%, 15%, 18% and 20%) including control specimens for both water-to-cement ratio is considered. Results of compressive strength, split tensile strength and flexural strength showed that the strength properties of concrete mixture decreased marginally with increase in wood ash contents, but strength increased with later age. The XRD test results and chemical analysis of WA showed that it contains amorphous silica and thus can be used as cement replacing material. Through the analysis of results obtained in this study, it was concluded that WA could be blended with cement without adversely affecting the strength properties of concrete. Also using a new statistical theory of the Support Vector Machine (SVM), strength parameters were predicted by developing a suitable model and as a result, the application of soft computing in structural engineering has been successfully presented in this research paper.

  20. Effects of pole compliance and step frequency on the biomechanics and economy of pole carrying during human walking.

    Science.gov (United States)

    Castillo, Eric R; Lieberman, Graham M; McCarty, Logan S; Lieberman, Daniel E

    2014-09-01

    This study investigates whether a flexible pole can be used as an energy-saving method for humans carrying loads. We model the carrier and pole system as a driven damped harmonic oscillator and predict that the energy expended by the carrier is affected by the compliance of the pole and the ratio between the pole's natural frequency and the carrier's step frequency. We tested the model by measuring oxygen consumption in 16 previously untrained male participants walking on a treadmill at four step frequencies using two loaded poles: one made of bamboo and one of steel. We found that when the bamboo pole was carried at a step frequency 20% greater than its natural frequency, the motions of the centers of mass of the load and carrier were approximately equal in amplitude and opposite in phase, which we predicted would save energy for the carrier. Carrying the steel pole, however, resulted in the carrier and loads oscillating in phase and with roughly equal amplitude. Although participants were less economical using poles than predicted costs using conventional fixed-load techniques (such as backpacks), the bamboo pole was on average 5.0% less costly than the steel pole. When allowed to select their cadence, participants also preferred to carry the bamboo pole at step frequencies of ∼2.0 Hz. This frequency, which is significantly higher than the preferred unloaded step frequency, is most economical. These experiments suggest that pole carriers can intuitively adjust their gaits, or choose poles with appropriate compliance, to increase energetic savings.

  1. MODELING OF THE FAST ORGANIC EMISSIONS FROM A WOOD-FINISHING PRODUCT -- FLOOR WAX

    Science.gov (United States)

    The paper discusses environmental chamber and full-scale residential house tests conducted to characterize the fast organic emissions from a wood finishing product, floor wax. For the environmental chamber tests, a very small amount (wax was applied to an alumi...

  2. Mathematical Simulation of Temperature Profiles within Microwave Heated Wood Made for Wood-Based Nanocomposites

    OpenAIRE

    Xianjun Li; Yongfeng Luo; Hongbin Chen; Xia He; Jianxiong Lv; Yiqiang Wu

    2013-01-01

    High intensive microwave pretreatment is a new method to modify wood for the fabrication of wood-based nanocomposites. 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 al...

  3. Source emission and model evaluation of formaldehyde from composite and solid wood furniture in a full-scale chamber

    Science.gov (United States)

    Liu, Xiaoyu; Mason, Mark A.; Guo, Zhishi; Krebs, Kenneth A.; Roache, Nancy F.

    2015-12-01

    This paper describes the measurement and model evaluation of formaldehyde source emissions from composite and solid wood furniture in a full-scale chamber at different ventilation rates for up to 4000 h using ASTM D 6670-01 (2007). Tests were performed on four types of furniture constructed of different materials and from different manufacturers. The data were used to evaluate two empirical emission models, i.e., a first-order and power-law decay model. The experimental results showed that some furniture tested in this study, made only of solid wood and with less surface area, had low formaldehyde source emissions. The effect of ventilation rate on formaldehyde emissions was also examined. Model simulation results indicated that the power-law decay model showed better agreement than the first-order decay model for the data collected from the tests, especially for long-term emissions. This research was limited to a laboratory study with only four types of furniture products tested. It was not intended to comprehensively test or compare the large number of furniture products available in the market place. Therefore, care should be taken when applying the test results to real-world scenarios. Also, it was beyond the scope of this study to link the emissions to human exposure and potential health risks.

  4. WOOD MODIFICATION BY HEAT TREATMENT: A REVIEW

    Directory of Open Access Journals (Sweden)

    Bruno M. Esteves

    2009-02-01

    Full Text Available Wood heat treatment has increased significantly in the last few years and is still growing as an industrial process to improve some wood properties. The first studies on heat treatment investigated mainly equilibrium mois-ture, dimensional stability, durability and mechanical properties. Mass loss, wettability, wood color, and chemical transformations have been subsequently extensively studied, while recent works focus on quality control, modeling, and study the reasons for the improvements. This review explains the recent interest on the heat treatment of wood and synthesizes the major publications on this subject on wood properties, chemical changes, wood uses, and quality control.

  5. Mathematical Modeling of Temperature Profiles in Wood During Microwave Heating%微波处理中木材内温度分布的数学模拟

    Institute of Scientific and Technical Information of China (English)

    李贤军; 孙伟圣; 周涛; 吕建雄

    2012-01-01

    A mass of heal will be generated inside the wood by the direct interaction between microwave eleclromagnetic Tiled and water molecule or polar group in wood, which can be used to dry wood quickly or for the modification pretreatmenl of wood. Based on the physical law on heat transfer, a mathematical model to describe the temperature profiles of wood during microwave drying was established and simulated in this research. The results showed that the temperature profiles and its uniformity inside wood are dependent on the microwave heating methods during a microwave drying. The temperature inside wood gradually decreased along the direction of microwave transmission when the unilateral microwave heating was applied during wood drying, and the curve of temperature profiles along the thickness direction of wood is not flat. The temperature gradient with the interior temperature higher than the one in the surface layers was presented inside wood when the bilateral microwave heating were applied for wood microwave drying. Compared with the unilateral microwave heating method, the temperature distribution is more uniform along the thickness direction inside wood for the bilateral microwave heating.%从热传导的物理规律出发,建立微波加热过程中木材内部热传导模型,并通过理论模拟揭示不同微波加热方式对预处理中木材内部温度分布的影响规律.结果表明:微波处理过程中,木材内部的温度分布规律及均匀性与微波加热方式直接相关;当采用单向微波辐射的方式进行加热时,沿着微波入射方向,木材温度逐渐降低,木材内部温差较大,且温度分布均匀性较差;当使用双向微波辐射的方式进行加热时,木材内能形成内高外低的温度梯度,且温度分布均匀性较好.

  6. International carbon accounting of harvested wood products: evaluation of two models for the quantification of wood product related emissions and removals

    NARCIS (Netherlands)

    Sikkema, R.; Schelhaas, M.J.; Nabuurs, G.J.

    2002-01-01

    At the moment three alternative approaches for estimating emissions and removals of CO2 from forest harvesting and wood products are under discussion. These are atmospheric flow approach, stock change approach, and the production approach. Several methodologies are being developed to deal with these

  7. 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)

  8. Electromechanical properties of a disc-type salient-pole brushless DC motor with different pole numbers

    Energy Technology Data Exchange (ETDEWEB)

    Lukaniszyn, M.; Jagiela, M.; Wrobel, R.

    2003-04-16

    A brushless, permanent magnet, three-phase disc-type salient-pole DC motor with co-axial flux in the stator is considered. Electromechanical properties of a basic eight-pole motor are compared with those for a 16-pole one of the same volume, in order to contrast the two potential candidates for variable-speed, low-cost drives. As a basis of the comparative analysis, 3D FEM magnetic field modelling and circuit analysis considering an electronic commutator are employed. Increasing the number of poles results in unfavourable raising in the switching frequency. The eight-pole motor construction has been shown in simulations to have higher efficiency and lower power losses than its 16-pole counterpart. (Author)

  9. Framework for modelling economic impacts of invasive species, applied to pine wood nematode in Europe.

    Directory of Open Access Journals (Sweden)

    Tarek Soliman

    Full Text Available BACKGROUND: Economic impact assessment of invasive species requires integration of information on pest entry, establishment and spread, valuation of assets at risk and market consequences at large spatial scales. Here we develop such a framework and demonstrate its application to the pinewood nematode, Bursaphelenchus xylophilus, which threatens the European forestry industry. The effect of spatial resolution on the assessment result is analysed. METHODOLOGY/PRINCIPAL FINDINGS: Direct economic impacts resulting from wood loss are computed using partial budgeting at regional scale, while impacts on social welfare are computed by a partial equilibrium analysis of the round wood market at EU scale. Substantial impacts in terms of infested stock are expected in Portugal, Spain, Southern France, and North West Italy but not elsewhere in EU in the near future. The cumulative value of lost forestry stock over a period of 22 years (2008-2030, assuming no regulatory control measures, is estimated at €22 billion. The greatest yearly loss of stock is expected to occur in the period 2014-2019, with a peak of three billion euros in 2016, but stabilizing afterwards at 300-800 million euros/year. The reduction in social welfare follows the loss of stock with considerable delay because the yearly harvest from the forest is only 1.8%. The reduction in social welfare for the downstream round wood market is estimated at €218 million in 2030, whereby consumers incur a welfare loss of €357 million, while producers experience a €139 million increase, due to higher wood prices. The societal impact is expected to extend to well beyond the time horizon of the analysis, and long after the invasion has stopped. CONCLUSIONS/SIGNIFICANCE: Pinewood nematode has large economic consequences for the conifer forestry industry in the EU. A change in spatial resolution affected the calculated directed losses by 24%, but did not critically affect conclusions.

  10. Biophysical modelling of intra-ring variations in tracheid features and wood density of Pinus pinaster trees exposed to seasonal droughts.

    Science.gov (United States)

    Wilkinson, Sarah; Ogée, Jérôme; Domec, Jean-Christophe; Rayment, Mark; Wingate, Lisa

    2015-03-01

    Process-based models that link seasonally varying environmental signals to morphological features within tree rings are essential tools to predict tree growth response and commercially important wood quality traits under future climate scenarios. This study evaluated model portrayal of radial growth and wood anatomy observations within a mature maritime pine (Pinus pinaster (L.) Aït.) stand exposed to seasonal droughts. Intra-annual variations in tracheid anatomy and wood density were identified through image analysis and X-ray densitometry on stem cores covering the growth period 1999-2010. A cambial growth model was integrated with modelled plant water status and sugar availability from the soil-plant-atmosphere transfer model MuSICA to generate estimates of cell number, cell volume, cell mass and wood density on a weekly time step. The model successfully predicted inter-annual variations in cell number, ring width and maximum wood density. The model was also able to predict the occurrence of special anatomical features such as intra-annual density fluctuations (IADFs) in growth rings. Since cell wall thickness remained surprisingly constant within and between growth rings, variations in wood density were primarily the result of variations in lumen diameter, both in the model and anatomical data. In the model, changes in plant water status were identified as the main driver of the IADFs through a direct effect on cell volume. The anatomy data also revealed that a trade-off existed between hydraulic safety and hydraulic efficiency. Although a simplified description of cambial physiology is presented, this integrated modelling approach shows potential value for identifying universal patterns of tree-ring growth and anatomical features over a broad climatic gradient.

  11. A Review of the Wood Pellet Value Chain, Modern Value/Supply Chain Management Approaches, and Value/Supply Chain Models

    Directory of Open Access Journals (Sweden)

    Natalie M. Hughes

    2014-01-01

    Full Text Available We reviewed 153 peer-reviewed sources to provide identification of modern supply chain management techniques and exploration of supply chain modeling, to offer decision support to managers. Ultimately, the review is intended to assist member-companies of supply chains, mainly producers, improve their current management approaches, by directing them to studies that may be suitable for direct application to their supply chains and value chains for improved efficiency and profitability. We found that information on supply chain management and modeling techniques in general is available. However, few Canadian-based published studies exist regarding a demand-driven modeling approach to value/supply chain management for wood pellet production. Only three papers were found specifically on wood pellet value chain analysis. We propose that more studies should be carried out on the value chain of wood pellet manufacturing, as well as demand-driven management and modeling approaches with improved demand forecasting methods.

  12. Air quality and residential wood combustion - application of the model system SIMAIRrwc for some Swedish municipalities; Luftkvalitet och smaaskalig biobraensleeldning. Tillaempningar av SIMAIRved foer naagra kommuner

    Energy Technology Data Exchange (ETDEWEB)

    Omstedt, Gunnar; Andersson, Stefan; Johansson, Christer; Loefgren, Bengt-Erik

    2008-11-15

    SIMAIRrwc is a Web based evaluation tool for meeting the EU directive on air pollution limits in residential areas using wood combustion. The background is a four-year research program (2001-2004) called Biomass Combustion Health and Environment. Some conclusions from this program were that emissions from small scale wood combustion can influence human health mainly due to high emitting old wood stoves during cold weather conditions and that the air quality in such areas can improve significantly if old wood stoves were replaced by modern wood boilers attached to a storage tank or with a pellet boiler. SIMAIRrwc is based on the same principles as SIMAIRroad, which is a Web based evaluation tool for road traffic i.e. coupled model system using different models on local, urban and regional geographical scales, best available emission data, but at the same time presented in a very simplified way. In this project SIMAIRrwc has been applied in five different Swedish municipalities. The aim has been to apply and improve the model in cooperation with the municipalities. The conclusions from the project are: Small scale wood combustions in residential areas are local problems which sometimes include only a few houses and/or wood-burners. Air quality problems related to the EU directive are mainly due to particles. Combinations of residential areas with wood combustion and emissions from nearby dense traffic roads might give rise to bad air quality. Actions require knowledge about individual equipment which needs information from the local chimney sweeps. The best way to identify problem areas is to use model calculations. If model calculations indicate risks of exceeding air quality limits, then new calculations should be made with improved input data taking into account for example information of district heating or other installations that can effect the emissions. Before actions are taken it may also be useful to make measurements. The measurement site can then be

  13. Toward forward modeling for paleoclimatic proxy signal calibration: A case study with oxygen isotopic composition of tropical woods

    Science.gov (United States)

    Evans, M. N.

    2007-07-01

    A forward model of the oxygen isotopic composition (δ18O) of wood cellulose is parameterized for time series prediction in tropical environments and driven with meteorological data observed at La Selva Biological Research Station, Costa Rica, for 1985-2001. Monthly-resolution model results correlate modestly (r = 0.34, p Selva suggests that isotopic variations are strongly controlled by rainfall amount. The model simulates an analogous but stronger than observed negative isotopic anomaly associated with positive July-September rainfall anomalies during El Niño-Southern Oscillation (ENSO) warm phase event years. Simulated tree isotope data for the global tropics suggest that a network of well-replicated data series from selected locations may resolve the large-scale precipitation anomaly pattern associated with ENSO.

  14. A multivariate mixed model system for wood specific gravity and moisture content of planted loblolly pine stands in the southern United States

    Science.gov (United States)

    Finto Antony; Laurence R. Schimleck; Alex Clark; Richard F. Daniels

    2012-01-01

    Specific gravity (SG) and moisture content (MC) both have a strong influence on the quantity and quality of wood fiber. We proposed a multivariate mixed model system to model the two properties simultaneously. Disk SG and MC at different height levels were measured from 3 trees in 135 stands across the natural range of loblolly pine and the stand level values were used...

  15. Developments to the Sylvan stand structure model to describe wood quality changes in southern bottomland hardwood forests because of forest management

    Science.gov (United States)

    David R. Larsen; Ian R. Scott

    2009-01-01

    Growth models can produce a wealth of detailed information that is often very difficult to perceive because it is frequently presented either as summary tables, stand view or landscape view visualizations. We have developed new tools for use with the Sylvan model (Larsen 1994) that allow the analysis of wood-quality changes as a consequence of forest management....

  16. Modeling the Effect of Geomorphic Change Triggered by Large Wood Addition on Salmon Habitat in a Forested Coastal Watershed

    Science.gov (United States)

    Bair, R.; Segura, C.; Lorion, C.

    2015-12-01

    Large wood (LW) additions are often part of fish habitat restorations in the PNW where historic forest clear-cutting limited natural wood recruitment. These efforts' relative successes are rarely reported in terms of ecological significance to different life stages of fish. Understanding the effectiveness of LW additions will contribute to successfully managing forest land. In this study we quantify the geomorphic change of a restoration project involving LW additions to three alluvial reaches in Mill Creek, OR. The reaches are 110-130m in plane-bed morphology and drain 2-16km2. We quantify the change in available habitat to different life stages of coho salmon in terms of velocity (v), shear stress (t), flow depth, and grain size distributions (GSD) considering existing thresholds in the literature for acceptable habitat. Flow conditions before and after LW additions are assessed using a 2D hydrodynamic model (FaSTMECH). Model inputs include detailed channel topography, discharge, and surface GSD. The spatial-temporal variability of sediment transport was also quantified based the modeled t distributions and the GSD to document changes in the overall geomorphic regime. Initial modeling results for pre wood conditions show mean t and v values ranging between 0 and 26N/m2 and between 0 and 2.4m/s, respectively for up to bankfull flow (Qbf). The distributions of both t and v become progressively wider and peak at higher values as flow increases with the notable exception at Qbf for which the area of low velocity increases noticeably. The spatial distributions of velocity results indicates that the extent of suitable habitat for adult coho decreased by 18% between flows 30 and 55% of BF. However the area of suitable habitat increased by 15% between 0.55Qbf and Qbf as the flow spreads from the channel into the floodplain. We expect the LW will enhance floodplain connectivity and thus available habitat by creating additional areas of low v during winter flows.

  17. Allometric Biomass, Biomass Expansion Factor and Wood Density Models for the OP42 Hybrid Poplar in Southern Scandinavia

    DEFF Research Database (Denmark)

    Nielsen, Anders Tærø; Nord-Larsen, Thomas; Stupak, Inge

    2015-01-01

    Biomass and biomass expansion factor functions are important in wood resource assessment, especially with regards to bioenergy feedstocks and carbon pools. We sampled 48 poplar trees in seven stands with the purpose of estimating allometric models for predicting biomass of individual tree...... components, stem-to-aboveground biomass expansion factors (BEF) and stem basic densities of the OP42 hybrid poplar clone in southern Scandinavia. Stand age ranged from 3 to 31 years, individual tree diameter at breast height (dbh) from 1.2 to 41 cm and aboveground tree biomass from 0.39 to 670 kg. Models...... for predicting total aboveground leafless, stem and branch biomass included dbh and tree height as predictor variables and explained more than 97 % of the total variation. The BEF was approaching 2.0 for the smallest trees but declined with increasing tree size and stabilized around 1.2 for trees with dbh >10 cm...

  18. Determination of the moisture content of Nordic spruce wood through cone heater experiments and an integral model

    DEFF Research Database (Denmark)

    Mindykowski, Pierrick Anthony; Jørgensen, M.; Svensson, Staffan

    2015-01-01

    The combination of cone heater experiments and an integral model was used to determine the moisture content of Nordic spruce with varying degree of drying. Nine specimens of Nordic spruce were pre-heated to 105°C in a convective oven for durations ranging from 0 days (no drying) and up to 63 days...... in increments of 7 days. The fuel moisture content was measured by weighting the specimens before and after the pre-heating. A mass loss cone was used to determine the time for piloted ignition of each specimen. A high-flux asymptotic solution from an integral model permitted to determine that the ignition...... is developed that can be used to determine the time to ignition of a piece of wet spruce, and it is suggested that this method can be used for establishing similar equations for other types of moist wood....

  19. The South Pole Telescope

    Energy Technology Data Exchange (ETDEWEB)

    Ruhl, J.E.; Ade, P.A.R.; Carlstrom, J.E.; Cho, H.M.; Crawford,T.; Dobbs, M.; Greer, C.H.; Halverson, N.W.; Holzapfel, W.L.; Lanting,T.M.; Lee, A.T.; Leitch, E.M.; Leong, J.; Lu, W.; Lueker, M.; Mehl, J.; Meyer, S.S.; Mohr, J.J.; Padin, S.; Plagge, T.; Pryke, C.; Runyan, M.C.; Schwan, D.; Sharp, M.K.; Spieler, H.; Staniszewski, Z.; Stark, A.A.

    2004-11-04

    A new 10 meter diameter telescope is being constructed for deployment at the NSF South Pole research station. The telescope is designed for conducting large-area millimeter and sub-millimeter wave surveys of faint, low contrast emission, as required to map primary and secondary anisotropies in the cosmic microwave background. To achieve the required sensitivity and resolution, the telescope design employs an off-axis primary with a 10 m diameter clear aperture. The full aperture and the associated optics will have a combined surface accuracy of better than 20 microns rms to allow precision operation in the submillimeter atmospheric windows. The telescope will be surrounded with a large reflecting ground screen to reduce sensitivity to thermal emission from the ground and local interference. The optics of the telescope will support a square degree field of view at 2mm wavelength and will feed a new 1000-element micro-lithographed planar bolometric array with superconducting transition-edge sensors and frequency-multiplexed readouts. The first key project will be to conduct a survey over 4000 degrees for galaxy clusters using the Sunyaev-Zeldovich Effect. This survey should find many thousands of clusters with a mass selection criteria that is remarkably uniform with redshift. Armed with redshifts obtained from optical and infrared follow-up observations, it is expected that the survey will enable significant constraints to be placed on the equation of state of the dark energy.

  20. The South Pole Telescope

    CERN Document Server

    Ruhl, J E; Carlstrom, J E; Cho, H M; Crawford, T; Dobbs, M; Greer, C H; Halverson, W; Holzapfel, W L; Lanting, T M; Lee, A T; Leong, J; Leitch, E M; Lu, W; Lueker, M; Mehl, J; Meyer, S S; Mohr, J J; Padin, S; Plagge, T; Pryke, C L; Schwan, D; Sharp, M K; Runyan, M C; Spieler, H; Staniszewski, Z; Stark, A A

    2004-01-01

    A new 10 meter diameter telescope is being constructed for deployment at the NSF South Pole research station. The telescope is designed for conducting large-area millimeter and sub-millimeter wave surveys of faint, low contrast emission, as required to map primary and secondary anisotropies in the cosmic microwave background. To achieve the required sensitivity and resolution, the telescope design employs an off-axis primary with a 10m diameter clear aperture. The full aperture and the associated optics will have a combined surface accuracy of better than 20 microns rms to allow precision operation in the submillimeter atmospheric windows. The telescope will be surrounded with a large reflecting ground screen to reduce sensitivity to thermal emission from the ground and local interference. The optics of the telescope will support a square degree field of view at 2mm wavelength and will feed a new 1000-element micro-lithographed planar bolometric array with superconducting transition-edge sensors and frequency...

  1. A model supported by GIS for locating and quantifying PM2.5 emission originated from residential wood burning

    Institute of Scientific and Technical Information of China (English)

    ZHOU De-min; RADKE John; TIAN Yong-qian; XU Jian-chun; MU Lan

    2005-01-01

    A research method was presented for spatially quantifying and allocating the potential activity of a fine particle matter emission (PM2.5), which originated from residential wood burning (RWB) in this study. Demographic, hypsographic, climatic and topographic data were compiled and processed within a geographic information system(GIS), and as independent variables put into a linear regression model for describing spatial distribution of the potential activity of residential wood burning as primary heating source. In order to improve the estimation, the classifications of urban, suburban and rural were redefined to meet the specifications of this application. Also, several definitions of forest accessibility were tested for estimation. The results suggested that the potential activity of RWB was mostly determined by elevation of a location, forest accessibility, urban/non-urban position, climatic conditions and several demographic variables. The linear regression model could explain approximately 86% of the variation of surveyed potential activity of RWB. The analysis results were validated by employing survey data collected mainly from a WebGIS based phone interview over the study area in central California. Based on lots free public GIS data, the model provided an easy and ideal tool for geographic researchers, environmental planners and administrators to understand where and how much PM2.5 emission from RWB was contributed to air quality. With this knowledge they could identify regions of concern, and better plan mitigation strategies to improve air quality. Furthermore, it allows for future adjustment on some parameters as the spatial analysis method is implemented in the different regions or various eco-social models.

  2. Finishes for Wood Decks

    Science.gov (United States)

    Mark Knaebe

    2013-01-01

    Wood decks have become an important part of residential construction. Wood decks can add versatile living space to a home and, with minimal maintenance, provide decades of use. However, wood decks are exposed to high levels of stress from severe weather conditions that shrink and swell the wood. Without proper maintenance, wood decks can develop problems such as checks...

  3. Occupational asthma caused by samba (Triplochiton scleroxylon wood dust in a professional maker of wooden models of airplanes: A case study

    Directory of Open Access Journals (Sweden)

    Patrycja Krawczyk-Szulc

    2014-08-01

    Full Text Available Objectives: Wood dust is a known occupational allergen that may induce, in exposed workers, respiratory diseases including asthma and allergic rhinitis. Samba (obeche, Triplochiton scleroxylon is a tropical tree, which grows in West Africa, therefore, Polish workers are rarely exposed to it. This paper describes a case of occupational asthma caused by samba wood dust. Material and Methods: The patient with suspicion of occupational asthma due to wood dust was examined at the Department of Occupational Diseases and Clinical Toxicology in the Nofer Institute of Occupational Medicine. Clinical evaluation included: analysis of occupational history, skin prick tests (SPT to common and occupational allergens, determination of serum specific IgE to occupational allergens, serial spirometry measurements, metacholine challenge test and specific inhalation challenge test with samba dust. Results: SPT and specific serum IgE assessment revealed sensitization to common and occupational allergens including samba. Spirometry measurements showed mild obstruction. Metacholine challenge test revealed a high level of bronchial hyperactivity. Specific inhalation challenge test was positive and cellular changes in nasal lavage and induced sputum confirmed allergic reaction to samba. Conclusions: IgE mediated allergy to samba wood dust was confirmed. This case report presents the first documented occupational asthma and rhinitis due to samba wood dust in wooden airplanes model maker in Poland.

  4. Modeling and Optimization of the Thermal Performance of a Wood-Cement Block in a Low-Energy House Construction

    Directory of Open Access Journals (Sweden)

    Iole Nardi

    2016-08-01

    Full Text Available The reduction of building energy consumption requires appropriate planning and design of the building’s envelope. In the last years, new innovative materials and construction technologies used in new or refurbished buildings have been developed in order to achieve this objective, which are also needed for reducing greenhouse gases emissions and building maintenance costs. In this work, the thermal conductance of a brick, made of wood and cement, used in a low-rise building, was investigated with a heat flow meter (HFM and with numerical simulation using the Ansys® software package (Canonsburg, PA, USA. Due to their influence on the buildings’ thermal efficiency, it is important to choose an appropriate design for the building blocks. Results obtained by the finite element modeling of the construction material and by in-situ analysis conducted on a real building are compared, and furthermore a thermal optimization of the shape of the material is suggested.

  5. Ground Wood Fiber Length Distributions

    Directory of Open Access Journals (Sweden)

    Lauri Ilmari Salminen

    2014-01-01

    Full Text Available This study considers ground wood fiber length distributions arising from pilot grindings. The empirical fiber length distributions appear to be independent of wood fiber length as well as feeding velocity. In terms of mathematics the fiber fragment distributions of ground wood pulp combine an exponential distribution for high-length fragments and a power-law distribution for smaller lengths. This implies that the fiber length distribution is influenced by the stone surface. A fragmentation-based model is presented that allows reproduction of the empirical results.

  6. Surmanuhtlusele pole kohta / Marianne Mikko

    Index Scriptorium Estoniae

    Mikko, Marianne, 1961-

    2008-01-01

    Surmanuhtlusest kui inimõiguste rängimast rikkumisest. Lisatud: surmanuhtlus arvudes. Ilmunud ka Hiiu Leht 14. okt. 2008, lk. 2 ; Põhjarannik 16. okt. 2008, lk. 4 ; Pärnu Postimees 11. okt. 2008, lk. 19 ; Hiiu Leht : Nädalalõpp 14. nov. 2008, lk. 6, pealkiri kujul: surmanuhtlusele pole Euroopas kohta ; Meie Maa : Nädalalõpp 14. nov. 2008, lk. 6, pealkiri kujul: surmanuhtlusele pole Euroopas kohta

  7. Force of habit: shrubs, trees and contingent evolution of wood anatomical diversity using Croton (Euphorbiaceae) as a model system.

    Science.gov (United States)

    Arévalo, Rafael; van Ee, Benjamin W; Riina, Ricarda; Berry, Paul E; Wiedenhoeft, Alex C

    2017-03-01

    Wood is a major innovation of land plants, and is usually a central component of the body plan for two major plant habits: shrubs and trees. Wood anatomical syndromes vary between shrubs and trees, but no prior work has explicitly evaluated the contingent evolution of wood anatomical diversity in the context of these plant habits. Phylogenetic comparative methods were used to test for contingent evolution of habit, habitat and wood anatomy in the mega-diverse genus Croton (Euphorbiaceae), across the largest and most complete molecular phylogeny of the genus to date. Plant habit and habitat are highly correlated, but most wood anatomical features correlate more strongly with habit. The ancestral Croton was reconstructed as a tree, the wood of which is inferred to have absent or indistinct growth rings, confluent-like axial parenchyma, procumbent ray cells and disjunctive ray parenchyma cell walls. The taxa sampled showed multiple independent origins of the shrub habit in Croton , and this habit shift is contingent on several wood anatomical features (e.g. similar vessel-ray pits, thick fibre walls, perforated ray cells). The only wood anatomical trait correlated with habitat and not habit was the presence of helical thickenings in the vessel elements of mesic Croton . Plant functional traits, individually or in suites, are responses to multiple and often confounding contexts in evolution. By establishing an explicit contingent evolutionary framework, the interplay between habit, habitat and wood anatomical diversity was dissected in the genus Croton . Both habit and habitat influence the evolution of wood anatomical characters, and conversely, the wood anatomy of lineages can affect shifts in plant habit and habitat. This study hypothesizes novel putatively functional trait associations in woody plant structure that could be further tested in a variety of other taxa.

  8. 基于遗传优化模型反向法变极的求解与算法%The Solution of Reverse-Current Pole-Changing and Its Algorithm Based on GA Optimization Model

    Institute of Scientific and Technical Information of China (English)

    于克训; 刘小洪

    2000-01-01

    The solution and algorithm of reverse-current pole-changing on the symmetrical block diagram and GA optimizing model are developed. The detailed mathematical flow is also presented with the corresponding computer software. The computer automation is realized in pole-changing winding design. Its practicability and advantages are proved in the example given.%基于变极绕组设计的对称块图法和遗传优化算法反向法变极的数学模型,提出了具体的求解方法及算法,给出了详细的计算流程图,研制了相应的计算机软件,实现了变极绕组设计的计算机自动化,实例证明了理论及方法的实用性及先进性.

  9. 基于遗传算法反向法变极的数学模型%The Mathematical Model of Reverse-Current Pole-Changing Winding Based on GA

    Institute of Scientific and Technical Information of China (English)

    于克训; 刘小洪

    2000-01-01

    A new algorithm has developed which is based on GA and "twin pole pairs slot-number phase diagram"-Symmetrical block diagram method, and given the description of its mathematical model for reverse current pole-changing winding. This model has been independent of the personal experience. The automation in pole-changing design has been realized.%基于变极绕组设计的双极对数槽号相位图和对称块图法,讨论了变极绕组设计的数学模型.将遗传算法引入变极绕组的自动设计中,以常用的反向法变极为例,提出了基于遗传算法的数学模型,从而为变极绕组设计的全自动化、全计算机化和全优化奠定了良好的基础.

  10. The Pole Orientation, Pole Precession, and Moment of Inertia Factor of Saturn

    Science.gov (United States)

    Jacobson, R. A.; French, R. G.; Nicholson, P. D.; Hedman, M.; Colwell, J. E.; Marouf, E.; Rappaport, N.; McGhee, C.; Sepersky, T.; Lonergan, K.

    2011-01-01

    This paper discusses our determination of the Saturn's pole orientation and precession using a combination of Earthbased and spacecraft based observational data. From our model of the polar motion and the observed precession rate we obtain a value for Saturn's polar moment of inertia

  11. Modeling the longitudinal variation in wood specific gravity of planted loblolly pine (Pinus taeda) in the United States

    Science.gov (United States)

    F. Antony; L. R. Schimleck; R. F. Daniels; Alexander Clark; D. B. Hall

    2010-01-01

    Loblolly pine (Pinus taeda L.) is a major plantation species grown in the southern United States, producing wood having a multitude of uses including pulp and lumber production. Specific gravity (SG) is an important property used to measure the quality of wood produced, and it varies regionally and within the tree with height and radius. SG at different height levels...

  12. Compressive Fatigue in Wood

    DEFF Research Database (Denmark)

    Clorius, Christian Odin; Pedersen, Martin Bo Uhre; Hoffmeyer, Preben;

    1999-01-01

    An investigation of fatigue failure in wood subjected to load cycles in compression parallel to grain is presented. Small clear specimens of spruce are taken to failure in square wave formed fatigue loading at a stress excitation level corresponding to 80% of the short term strength. Four...... frequencies ranging from 0.01 Hz to 10 Hz are used. The number of cycles to failure is found to be a poor measure of the fatigue performance of wood. Creep, maximum strain, stiffness and work are monitored throughout the fatigue tests. Accumulated creep is suggested identified with damage and a correlation...... is observed between stiffness reduction and accumulated creep. A failure model based on the total work during the fatigue life is rejected, and a modified work model based on elastic, viscous and non-recovered viscoelastic work is experimentally supported, and an explanation at a microstructural level...

  13. GUIDELESS SPATIAL COORDINATE MEASUREMENT TECHNOLOGY BASED ON CODING POLE

    Institute of Scientific and Technical Information of China (English)

    ZHAO Min; QIU Zongming; QU Jiamin; LIU Hongzhao

    2008-01-01

    A new method of guideless spatial coordinate measurement technology based on coding pole and vision measurement is proposed. Unequal spacing of bar code is adopted to pole, so that the code combination of pole image in measuring field is unique. Holographic characteristics of numeric coding pole are adopted to obtain pole pose and pole probe position by any section of bar code on the pole. Spatial coordinates of measuring points can be obtained by coordinate transform. The contradiction between high resolution and large visual field of image sensor is resolved, thereby providing a new concept for surface shape measurement of large objects with high precision. The measurement principles of the system are expounded and mathematic model is established. The measurement equation is evaluated by simulation experiments and the measurement precision is analyzed. Theoretical analysis and simulation experiments prove that this system is characterized by simple structure and wide measurement range. Therefore it can be used in the 3-dimentional coordinate measurement of large objects.

  14. Pole Inflation - Shift Symmetry and Universal Corrections

    CERN Document Server

    Broy, Benedict J; Roest, Diederik; Westphal, Alexander

    2015-01-01

    An appealing explanation for the Planck data is provided by inflationary models with a non-canonical kinetic term: a Laurent expansion of the kinetic function translates into a potential with a nearly shift-symmetric plateau in canonical fields. The shift symmetry can be broken at large field values by including higher-order poles. We show that the resulting corrections to the inflationary dynamics and predictions are universal at lowest order, and can induce power loss at large angular scales. At lowest order there are no corrections from a pole of one order higher; this is referred to as extended no-scale in string theory and we explain why this is a general phenomenon. Finally, we outline which other corrections may arise as string loop corrections.

  15. THE USE OF MATHEMATICAL MODELS FOR ESTIMATING WOOD BASIC DENSITY OF Eucalyptus sp CLONES

    Directory of Open Access Journals (Sweden)

    Cláudio Roberto Thiersch

    2006-09-01

    Full Text Available This study aimed at identifying at what point in the stem, in the longitudinal and cardinal direction, the pylodin penetration depth should be measured, for determining wood basic density, envisaging forestry inventory Data base used in compassed 36 parcels of 400 m2. Around the parcels 216 trees were sealed. Two clones (hybrid of E. grandis and E. urophylla, at the ages of 3; 4, 5 and 6 years, belonging to three different sites in East Brazil, encompassing East and Northeast of Espirito Santo state and south of Bahia state. In each measuring height of diameters it was also measured the penetration depth of the pylodin (in mm. The average basic density of scaled trees, was determined, departing from the cheaps, using the immersion method. The main conclusions were: The density equation, as function of the pylodin measures, age, site, diameters at 1.3m of ground and total height, was more precise, exact and stable than the density equation as function of pylodin, age, site and diameter, which in turn was more exact and stable than the density equation, as function of pylodin measures, age, site, diameter at a 1.3m of the ground and of total height, was precise and exact for all ages and sites, in dependent on if the pylodin measurements were taken in the South or in North fares, or in the average position between them. The height for measurement with pylodin can also be taken in the more ergonomic position of 1.3m. The density estimation, as a function of the measures with the pylodin, or as a function of the use of the pylodin, age, average dominant tree height an diameter at 1.3m of the ground, for both clones, was more precise when the measure with the pylodin was taken at the North face. The average tree basic density must always be taken by a specific equation for each clone, given that these equations differ statistically.

  16. Bridging gaps: On the performance of airborne LiDAR to model wood mouse-habitat structure relationships in pine forests.

    Science.gov (United States)

    Jaime-González, Carlos; Acebes, Pablo; Mateos, Ana; Mezquida, Eduardo T

    2017-01-01

    LiDAR technology has firmly contributed to strengthen the knowledge of habitat structure-wildlife relationships, though there is an evident bias towards flying vertebrates. To bridge this gap, we investigated and compared the performance of LiDAR and field data to model habitat preferences of wood mouse (Apodemus sylvaticus) in a Mediterranean high mountain pine forest (Pinus sylvestris). We recorded nine field and 13 LiDAR variables that were summarized by means of Principal Component Analyses (PCA). We then analyzed wood mouse's habitat preferences using three different models based on: (i) field PCs predictors, (ii) LiDAR PCs predictors; and (iii) both set of predictors in a combined model, including a variance partitioning analysis. Elevation was also included as a predictor in the three models. Our results indicate that LiDAR derived variables were better predictors than field-based variables. The model combining both data sets slightly improved the predictive power of the model. Field derived variables indicated that wood mouse was positively influenced by the gradient of increasing shrub cover and negatively affected by elevation. Regarding LiDAR data, two LiDAR PCs, i.e. gradients in canopy openness and complexity in forest vertical structure positively influenced wood mouse, although elevation interacted negatively with the complexity in vertical structure, indicating wood mouse's preferences for plots with lower elevations but with complex forest vertical structure. The combined model was similar to the LiDAR-based model and included the gradient of shrub cover measured in the field. Variance partitioning showed that LiDAR-based variables, together with elevation, were the most important predictors and that part of the variation explained by shrub cover was shared. LiDAR derived variables were good surrogates of environmental characteristics explaining habitat preferences by the wood mouse. Our LiDAR metrics represented structural features of the forest

  17. Low loss pole configuration for multi-pole homopolar magnetic bearings

    Science.gov (United States)

    Blumenstock, Kenneth A. (Inventor); Hakun, Claef F. (Inventor)

    2001-01-01

    A new pole configuration for multi-pole homopolar bearings proposed in this invention reduces rotational losses caused by eddy-currents generated when non-uniform flux distributions exist along the rotor surfaces. The new homopolar magnetic bearing includes a stator with reduced pole-to-pole and exhibits a much more uniform rotor flux than with large pole-to-pole gaps. A pole feature called a pole-link is incorporated into the low-loss poles to provide a uniform pole-to-pole gap and a controlled path for pole-to-pole flux. In order to implement the low-loss pole configuration of magnetic bearings with small pole-to-pole gaps, a new stator configuration was developed to facilitate installation of coil windings. The stator was divided into sector shaped pieces, as many pieces as there are poles. Each sector-shaped pole-piece can be wound on a standard coil winding machine, and it is practical to wind precision layer wound coils. To achieve maximum actuation efficiency, it is desirable to use all the available space for the coil formed by the natural geometric configuration. Then, the coils can be wound in a tapered shape. After winding, the sectored-pole-pieces are installed into and fastened by bonding or other means, to a ring of material which encloses the sectored-pole-pieces, forming a complete stator.

  18. Decentralized-feedback pole placement of linear systems

    Science.gov (United States)

    Wang, X.; Martin, C. F.; Gilliam, D.; Byrnes, C. I.

    1992-01-01

    A projectile product spaces model is used to analyze decentralized systems. The degree of the pole placement map is computed. The conditions under which the degree is odd are also given. Twin lift systems are studied. It is proved that the poles of a twin lift system can be assigned to any values by local static and local dynamic feedback laws if and only if the system is jointly controllable.

  19. Wood-Burning Device Changeout: Modeling the Impact on PM2.5 Concentrations in a Remote Subarctic Urban Nonattainment Area

    Directory of Open Access Journals (Sweden)

    Huy N. Q. Tran

    2012-01-01

    Full Text Available The effects of exchanging noncertified with certified wood-burning devices on the 24h-average PM2.5 concentrations in the nonattainment area of Fairbanks, Alaska, in a cold season (October to March were investigated using the Weather Research and Forecasting model inline coupled with a chemistry package. Even changing out only 2930 uncertified woodstoves and 90 outdoor wood boilers reduced the 24 h-average PM2.5 concentrations on average by 0.6 μg.m−3 (6% and avoided seven out of 55 simulated exceedance days during this half-a-year. The highest reductions on any exceedance day ranged between 1.7 and 2.8 μg.m−3. The relative response factors obtained were consistently relatively low (~0.95 for all PM2.5 species and all months. Sensitivity studies suggest that the assessment of the benefits of a wood-burning device changeout program in avoiding exceedances heavily relies on the accuracy of the estimates on how many wood-burning devices exist that can be exchanged.

  20. Calligraphic Poling for WGM Resonators

    Science.gov (United States)

    Mohageg, Makan; Strekalov, Dmitry; Savchenkov, Anatoliy; Matsko, Andrey; Ilchenko, Vladimir; Maleki, Lute

    2007-01-01

    By engineering the geometry of a nonlinear optical crystal, the effective efficiency of all nonlinear optical oscillations can be increased dramatically. Specifically, sphere and disk shaped crystal resonators have been used to demonstrate nonlinear optical oscillations at sub-milliwatt input power when cs light propagates in a Whispering Gallery Mode (WGM) of such a resonant cavity. in terms of both device production and experimentation in quantum optics, some nonlinear optical effects with naturally high efficiency can occult the desired nonlinear scattering process. the structure to the crystal resonator. In this paper, I will discuss a new method for generating poling structures in ferroelectric crystal resonators called calligraphic poling. The details of the poling apparatus, experimental results and speculation on future applications will be discussed.

  1. Calligraphic Poling of Ferroelectric Material

    Science.gov (United States)

    Mohageg, Makan; Strekalov, Dmitry; Savchenkov, Anatoliy; Matsko, Adrey; Maleki, Lute; Iltchenko, Vladimir

    2007-01-01

    Calligraphic poling is a technique for generating an arbitrary, possibly complex pattern of localized reversal in the direction of permanent polarization in a wafer of LiNbO3 or other ferroelectric material. The technique is so named because it involves a writing process in which a sharp electrode tip is moved across a surface of the wafer to expose the wafer to a polarizing electric field in the desired pattern. The technique is implemented by use of an apparatus, denoted a calligraphic poling machine (CPM), that includes the electrode and other components as described in more detail below.

  2. Modelling and simulation of wood chip combustion in a hot air generator system

    National Research Council Canada - National Science Library

    Rajika, J K. A. T; Narayana, Mahinsasa

    2016-01-01

    .... Open-source CFD tool; OpenFOAM was used to generate CFD model source code for the packed bed combustion and simulated along with an available solver for free board region modelling in the CFD tool...

  3. Tribology in secondary wood machining

    Energy Technology Data Exchange (ETDEWEB)

    Ko, P.L.; Hawthorne, H.M.; Andiappan, J.

    1998-07-01

    Secondary wood manufacturing covers a wide range of products from furniture, cabinets, doors and windows, to musical instruments. Many of these are now mass produced in sophisticated, high speed numerical controlled machines. The performance and the reliability of the tools are key to an efficient and economical manufacturing process as well as to the quality of the finished products. A program concerned with three aspects of tribology of wood machining, namely, tool wear, tool-wood friction characteristics and wood surface quality characterization, was set up in the Integrated Manufacturing Technologies Institute (IMTI) of the National Research Council of Canada. The studies include friction and wear mechanism identification and modeling, wear performance of surface-engineered tool materials, friction-induced vibration and cutting efficiency, and the influence of wear and friction on finished products. This research program underlines the importance of tribology in secondary wood manufacturing and at the same time adds new challenges to tribology research since wood is a complex, heterogeneous, material and its behavior during machining is highly sensitive to the surrounding environments and to the moisture content in the work piece.

  4. Method for Eliminating LCD Motion De-blurring Model's Pole%一种消除LCD运动图像去模糊模型极点的方法

    Institute of Scientific and Technical Information of China (English)

    朱雄泳; 周杰; 谭洪舟

    2012-01-01

    sinc-1模型作为逆系统能较好地改善LCD运动图像模糊现象,但其在极点处无法正确还原运动模糊的图像,且难以硬件实现.因此,本文从系统辨识的角度出发,提出了一种采用基于变步长最小均方误差(Least mean square,LMS)的低阶Volterra非线性系统拟合sinc-模型的LCD运动图像去模糊的方法.仿真结果表明,该方法能消除sinc-1模型的极点问题,较好地改善了LCD运动图像模糊现象,简单且易于硬件实现.%The sinc-1 model can reduce the LCD motion blur effectively, however, it can not restore the correct frequency components on the pole and is hard to implement on hardware. This paper presents a novel method which is trying to improve the LCD motion blur phenomenon from the view of system identification. The method uses the Volterra nonlinear system that is based on the VSSLMS (variable step size least mean square) algorithm to fit the sine"1 model, which is a non-perfect inverse system to the LCD motion blur system for the pole problem. Simulation results demonstrate that the performance of the proposed simple method can avoid the pole problem of sine"1 model and can be implemented on hardware easily.

  5. A new Model Applicable for Finite Element Simulations of Moisture Transport in Wood

    DEFF Research Database (Denmark)

    Frandsen, Henrik Lund; Svensson, Staffan; Damkilde, Lars

    2006-01-01

    mathematical models for hysteresis e.g. the independent domain model are complicated and have numerical deficiencies. The paper presents a new hysteresis model with closed-form expressions and current relative humidity and moisture content as the only input parameters. In addition the method is general...

  6. Glass Waveguides for Periodic Poling

    DEFF Research Database (Denmark)

    Fage-Pedersen, Jacob; Jacobsen, Rune Shim; Kristensen, Martin

    2005-01-01

    Planar silica-based waveguide devices have been developed for second-harmonic generation by poling with periodic electrodes. We show that detrimental charge transport can occur along interfaces, but with proper choice of fabrication, high-quality devices are obtained....

  7. Kool pole vabrik / Peeter Kreitzberg

    Index Scriptorium Estoniae

    Kreitzberg, Peeter, 1948-2011

    2003-01-01

    Riigikogu liige Peeter Kreitzberg nimetab Res Publica kavandatavat koolireformi kirvereformiks, mis ei lähtu hariduse põhiprobleemidest. Autor pooldab haridusvõimaluste regionaalset võrdsust ning leiab, et hariduses pole vaja võistlust mõttetult õhutada

  8. Glass Waveguides for Periodic Poling

    DEFF Research Database (Denmark)

    Fage-Pedersen, Jacob; Jacobsen, Rune Shim; Kristensen, Martin

    2005-01-01

    Planar silica-based waveguide devices have been developed for second-harmonic generation by poling with periodic electrodes. We show that detrimental charge transport can occur along interfaces, but with proper choice of fabrication, high-quality devices are obtained....

  9. Kool pole vabrik / Peeter Kreitzberg

    Index Scriptorium Estoniae

    Kreitzberg, Peeter, 1948-2011

    2003-01-01

    Riigikogu liige Peeter Kreitzberg nimetab Res Publica kavandatavat koolireformi kirvereformiks, mis ei lähtu hariduse põhiprobleemidest. Autor pooldab haridusvõimaluste regionaalset võrdsust ning leiab, et hariduses pole vaja võistlust mõttetult õhutada

  10. Kinetic Modeling of Ethanol Batch Fermentation by Escherichia Coli FBWHR Using Hot-Water Sugar Maple Wood Extract Hydrolyzate as Substrate

    Directory of Open Access Journals (Sweden)

    Yang Wang

    2014-12-01

    Full Text Available A recombinant strain of Escherichia coli FBWHR was used for ethanol fermentation from hot-water sugar maple wood extract hydrolyzate in batch experiments. Kinetic studies of cell growth, sugar utilization and ethanol production were investigated at different initial total sugar concentrations of wood extract hydrolyzate. The highest ethanol concentration of 24.05 g/L was obtained using an initial total sugar concentration of 70.30 g/L. Unstructured models were developed to describe cell growth, sugar utilization and ethanol production and validated by comparing the predictions of model and experimental data. The results from this study could be expected to provide insights into the process performance, optimize the process and aid in the design of processes for large-scale production of ethanol fermentation from woody biomass.

  11. Numerical modeling of combustion of low-calorific-producer-gas from Mangium wood within a late mixing porous burner (LMPB

    Directory of Open Access Journals (Sweden)

    Kanokkarn Jirakulsomchok

    2017-08-01

    Full Text Available This article presents a numerical study of combustion of low-calorific-producer-gas from Mangium wood within a late mixing porous burner (LMPB. The LMPB consists of four main components, i.e., the fuel preheating porous (FP, the porous combustor (PC, the air jacket, and the mixing chamber. Interestingly, this LMPB was able to highly preheated and it still maintained high safety in operation. A single-step global reaction, steady state approach and a one-dimensional model were considered. The necessary information for burner characteristics, i.e., temperature profile, flame location and maximum temperature were also presented. The results indicated that stable combustion of a low-calorific-producer-gas within LMPB was possible achieved. Increasing equivalence ratio resulted in increasing in the flame temperature. Meanwhile, increasing the firing rate caused slightly decrease in flame temperature. The flame moved to downstream zone of the PC when the firing rate increased. Finally, it was found that the equivalence ratio did not affect the flame location.

  12. Monitoring ambient air pollutants and apply Woods' model in the prediction seasonal dry deposition at Chang-Hua (urban) and Kao-Mei (wetland) county, Taiwan.

    Science.gov (United States)

    Fang, Guor-Cheng; Chang, Chia-Ying

    2014-09-01

    The main purpose for this study was to monitor ambient air particles and metallic elements (Mn, Fe, Zn, Cr, Cu and Pb) in total suspended particulate (TSP) concentration and dry deposition. In addition, the calculated/measured dry deposition flux ratios of ambient air particles and metallic elements (Mn, Fe, Zn, Cr, Cu and Pb) were evaluated using Woods' model at urban and wetland areas for the 2009-2010 period. The results indicated that the mean highest concentrations of metallic elements Mn, Fe, Zn, Cr, Cu and Pb in TSP were found in Chang-Hua (urban) sampling site. And as for the two characteristic sampling sites, the Woods' model exhibits better dry deposition of particulates of 18 µm particle size than the rest of the other particle sizes at any sampling site in this study. The average calculated/measured flux ratios for two seasons (summer and fall) by using Woods model at 2.5, 10 and 18 µm particles sizes were also studied. The results indicated that the average calculated/measured flux ratios orders for two seasons of various particles sizes were all displayed as Fe > Mn > Zn > Cu > Cr > Pb > particle. And these calculated/measured flux ratios orders were Fe > Mn > Cu > Zn > Cr > Pb > particle and were Fe > Mn > Zn > Cu > Cr > particle > Pb, during spring and winter seasons, respectively. Finally, in the spring and summer seasons of Gao-Mei (wetland) sampling site, the average calculated/measured flux ratios using Woods' model was found to be 2.5, 10 and 18 µm, showing the order of the calculated/measured flux ratios to be Fe > Cu > Zn > Mn > Cr > Pb > particle. And the calculated/measured flux ratio orders were Fe > Zn > Mn > Cu > Cr > particle > Pb and were Fe > Cu > Zn > Mn > Cr > particle > Pb for fall and winter season, respectively.

  13. Taxonomy and phylogeny of new wood- and soil-inhabiting Sporothrix species in the Ophiostoma stenoceras-Sporothrix schenckii complex.

    NARCIS (Netherlands)

    de Meyer, E.M.; de Beer, Z.W.; Summerbell, R.C.; Moharram, A.M.; de Hoog, G.S.; Vismer, H.F.; Wingfield, M.J.

    2008-01-01

    Sporothrix, one of the anamorph genera of Ophiostoma, includes the important human pathogen S. schenckii and various fungi associated with insects and sap stain of wood. A survey of fungi from wood utility poles in South Africa yielded two distinct groups of Sporothrix isolates from different geogra

  14. The modelling of time-dependant deformation in wood using chemical kinetics

    NARCIS (Netherlands)

    Bonfield, P.W.; Mundy, J.; Robson, D.J.; Dinwoodie, J.M.

    1996-01-01

    The development of rheological models to predict creep has led to the derivation of quite complex equations that can predict creep reasonably accurately. However, these models are conceptual and are not based on a fundamental under-standing of the actual deformation processes occurring within the ma

  15. Evaluating Economic Impacts of Expanded Global Wood Energy Consumption with the USFPM/GFPM Model

    Science.gov (United States)

    Peter J. Ince; Andrew Kramp; Kenneth E. Skog

    2012-01-01

    A U.S. forest sector market module was developed within the general Global Forest Products Model. The U.S. module tracks regional timber markets, timber harvests by species group, and timber product outputs in greater detail than does the global model. This hybrid approach provides detailed regional market analysis for the United States although retaining the...

  16. Apply Woods Model in the Predictions of Ambient Air Particles and Metallic Elements (Mn, Fe, Zn, Cr, and Cu at Industrial, Suburban/Coastal, and Residential Sampling Sites

    Directory of Open Access Journals (Sweden)

    Guor-Cheng Fang

    2012-01-01

    Full Text Available The main purpose for this study was to monitor ambient air particles and metallic elements (Mn, Fe, Zn, Cr, and Cu in total suspended particulates (TSPs concentration, dry deposition at three characteristic sampling sites of central Taiwan. Additionally, the calculated/measured dry deposition flux ratios of ambient air particles and metallic elements were calculated with Woods models at these three characteristic sampling sites during years of 2009-2010. As for ambient air particles, the results indicated that the Woods model generated the most accurate dry deposition prediction results when particle size was 18 μm in this study. The results also indicated that the Woods model exhibited better dry deposition prediction performance when the particle size was greater than 10 μm for the ambient air metallic elements in this study. Finally, as for Quan-xing sampling site, the main sources were many industrial factories under process around these regions and were severely polluted areas. In addition, the highest average dry deposition for Mn, Fe, Zn, and Cu species occurred at Bei-shi sampling site, and the main sources were the nearby science park, fossil fuel combustion, and Taichung thermal power plant (TTPP. Additionally, as for He-mei sampling site, the main sources were subjected to traffic mobile emissions.

  17. Modelling solid-convective flash pyrolysis of straw and wood in the Pyrolysis Centrifuge Reactor

    DEFF Research Database (Denmark)

    Bech, Niels; Larsen, Morten Boberg; Jensen, Peter Arendt

    2009-01-01

    Less than a handful of solid-convective pyrolysis reactors for the production of liquid fuel from biomass have been presented and for only a single reactor a detailed mathematical model has been presented. In this article we present a predictive mathematical model of the pyrolysis process...... in the Pyrolysis Centrifuge Reactor, a novel solid-convective flash pyrolysis reactor. The model relies on the original concept for ablative pyrolysis of particles being pyrolysed through the formation of an intermediate liquid compound which is further degraded to form liquid organics, char, and gas. To describe...... that the reacting particle continuously shed the formed char layer....

  18. Modeling the Emission of CO from Wood Fires using Detailed Chemical Kinetics

    DEFF Research Database (Denmark)

    Dederichs, Anne

    Carbon monoxide is treated as one of the most common and dangerous of gases evolving in fires. Modeling the formation of the toxic gas CO from in fire enclosures using detailed chemical kinetics is the topic of this manuscript. A semi-empirical model is developed to study the formation of CO from......, the model separately treats the process of pyrolysis and combustion. For under ventilated conditions and at high temperatures during pyrolysis it is found that the process of pyrolysation strongly influences the formation of CO in fire. CO2 follows the same trend....

  19. DETECTION AND CLASSIFICATION OF POLE-LIKE OBJECTS FROM MOBILE MAPPING DATA

    Directory of Open Access Journals (Sweden)

    K. Fukano

    2015-08-01

    Full Text Available Laser scanners on a vehicle-based mobile mapping system can capture 3D point-clouds of roads and roadside objects. Since roadside objects have to be maintained periodically, their 3D models are useful for planning maintenance tasks. In our previous work, we proposed a method for detecting cylindrical poles and planar plates in a point-cloud. However, it is often required to further classify pole-like objects into utility poles, streetlights, traffic signals and signs, which are managed by different organizations. In addition, our previous method may fail to extract low pole-like objects, which are often observed in urban residential areas. In this paper, we propose new methods for extracting and classifying pole-like objects. In our method, we robustly extract a wide variety of poles by converting point-clouds into wireframe models and calculating cross-sections between wireframe models and horizontal cutting planes. For classifying pole-like objects, we subdivide a pole-like object into five subsets by extracting poles and planes, and calculate feature values of each subset. Then we apply a supervised machine learning method using feature variables of subsets. In our experiments, our method could achieve excellent results for detection and classification of pole-like objects.

  20. Detection and Classification of Pole-Like Objects from Mobile Mapping Data

    Science.gov (United States)

    Fukano, K.; Masuda, H.

    2015-08-01

    Laser scanners on a vehicle-based mobile mapping system can capture 3D point-clouds of roads and roadside objects. Since roadside objects have to be maintained periodically, their 3D models are useful for planning maintenance tasks. In our previous work, we proposed a method for detecting cylindrical poles and planar plates in a point-cloud. However, it is often required to further classify pole-like objects into utility poles, streetlights, traffic signals and signs, which are managed by different organizations. In addition, our previous method may fail to extract low pole-like objects, which are often observed in urban residential areas. In this paper, we propose new methods for extracting and classifying pole-like objects. In our method, we robustly extract a wide variety of poles by converting point-clouds into wireframe models and calculating cross-sections between wireframe models and horizontal cutting planes. For classifying pole-like objects, we subdivide a pole-like object into five subsets by extracting poles and planes, and calculate feature values of each subset. Then we apply a supervised machine learning method using feature variables of subsets. In our experiments, our method could achieve excellent results for detection and classification of pole-like objects.

  1. The dynamic of the annual carbon allocation to wood in European tree species is consistent with a combined source-sink limitation of growth: implications for modelling

    Science.gov (United States)

    Guillemot, J.; Martin-StPaul, N. K.; Dufrene, E.; Francois, C.; Soudani, K.; Ourcival, J. M.; Delpierre, N.

    2015-05-01

    appeared to strongly limit growth only in temperate deciduous species. We provide an evaluation of the spatio-temporal dynamics of the annual C allocation to wood in French forests. Our study supports the premise that the growth of European tree species is subject to complex control processes that include both source and sink limitations. The relative influences of the growth drivers strongly vary with time and across spatial ecological gradients. We suggest a straightforward modelling framework with which to implement these combined forest growth limitations into terrestrial biosphere models.

  2. Evaluation of the impact of wood combustion on benzo[a]pyrene (BaP) concentrations; ambient measurements and dispersion modeling in Helsinki, Finland

    Science.gov (United States)

    Hellén, Heidi; Kangas, Leena; Kousa, Anu; Vestenius, Mika; Teinilä, Kimmo; Karppinen, Ari; Kukkonen, Jaakko; Niemi, Jarkko V.

    2017-03-01

    Even though emission inventories indicate that wood combustion is a major source of polycyclic aromatic hydrocarbons (PAHs), estimating its impacts on PAH concentration in ambient air remains challenging. In this study the effect of local small-scale wood combustion on the benzo[a]pyrene (BaP) concentrations in ambient air in the Helsinki metropolitan area in Finland is evaluated, using ambient air measurements, emission estimates, and dispersion modeling. The measurements were conducted at 12 different locations during the period from 2007 to 2015. The spatial distributions of annual average BaP concentrations originating from wood combustion were predicted for four of those years: 2008, 2011, 2013, and 2014. According to both the measurements and the dispersion modeling, the European Union target value for the annual average BaP concentrations (1 ng m-3) was clearly exceeded in certain suburban detached-house areas. However, in most of the other urban areas, including the center of Helsinki, the concentrations were below the target value. The measured BaP concentrations highly correlated with the measured levoglucosan concentrations in the suburban detached-house areas. In street canyons, the measured concentrations of BaP were at the same level as those in the urban background, clearly lower than those in suburban detached-house areas. The predicted annual average concentrations matched with the measured concentrations fairly well. Both the measurements and the modeling clearly indicated that wood combustion was the main local source of ambient air BaP in the Helsinki metropolitan area.

  3. From models to measurements: comparing downed dead wood carbon stock estimates in the U.S. forest inventory.

    Directory of Open Access Journals (Sweden)

    Grant M Domke

    Full Text Available The inventory and monitoring of coarse woody debris (CWD carbon (C stocks is an essential component of any comprehensive National Greenhouse Gas Inventory (NGHGI. Due to the expense and difficulty associated with conducting field inventories of CWD pools, CWD C stocks are often modeled as a function of more commonly measured stand attributes such as live tree C density. In order to assess potential benefits of adopting a field-based inventory of CWD C stocks in lieu of the current model-based approach, a national inventory of downed dead wood C across the U.S. was compared to estimates calculated from models associated with the U.S.'s NGHGI and used in the USDA Forest Service, Forest Inventory and Analysis program. The model-based population estimate of C stocks for CWD (i.e., pieces and slash piles in the conterminous U.S. was 9 percent (145.1 Tg greater than the field-based estimate. The relatively small absolute difference was driven by contrasting results for each CWD component. The model-based population estimate of C stocks from CWD pieces was 17 percent (230.3 Tg greater than the field-based estimate, while the model-based estimate of C stocks from CWD slash piles was 27 percent (85.2 Tg smaller than the field-based estimate. In general, models overestimated the C density per-unit-area from slash piles early in stand development and underestimated the C density from CWD pieces in young stands. This resulted in significant differences in CWD C stocks by region and ownership. The disparity in estimates across spatial scales illustrates the complexity in estimating CWD C in a NGHGI. Based on the results of this study, it is suggested that the U.S. adopt field-based estimates of CWD C stocks as a component of its NGHGI to both reduce the uncertainty within the inventory and improve the sensitivity to potential management and climate change events.

  4. The science of the lunar poles

    Science.gov (United States)

    Lucey, P. G.

    2011-12-01

    It was the great geochemist Harold Urey who first called attention to peculiar conditions at the poles of the Moon where the very small inclination of the lunar spin axis with respect to the sun causes craters and other depressions to be permanently shaded from sunlight allowing very low temperatures. Urey suggested that the expected low temperature surfaces could cold trap and collect any vapors that might transiently pass through the lunar environment. Urey's notion has led to studies of the poles as a new research area in lunar science. The conditions and science of the poles are utterly unlike those of the familiar Moon of Neil Armstrong, and the study of the poles is similar to our understanding of the Moon itself at the dawn of the space age, with possibilities outweighing current understanding. Broadly, we can treat the poles as a dynamic system of input, transport, trapping, and loss. Volatile sources range from continuous, including solar wind, the Earth's polar fountain and micrometeorites, to episodic, including comets and wet asteroids, to nearly unique events including late lunar outgassing and passage through giant molecular clouds. The lunar exosphere transports volatiles to the poles, complicated by major perturbances to the atmosphere by volatile-rich sources. Trapping includes cold trapping, but also in situ creation of more refractory species such as organics, clathrates and water-bearing minerals, as well as sequester by regolith overturn or burial by larger impacts. Finally, volatiles are lost to space by ionization and sweeping. Spacecraft results have greatly added to the understanding of the polar system. Temperatures have been precisely measured by LRO, and thermal models now allow determination of temperature over the long evolution of the lunar orbit, and show very significant changes in temperature and temperature distribution with time and depth. Polar topography is revealed in detail by Selene and LRO laser altimeters while direct

  5. Resonance poles in three-body systems

    Science.gov (United States)

    Pearce, B. C.; Afnan, I. R.

    1984-12-01

    We develop a method for finding resonance poles in Faddeev equations. The method is computationally simpler than previous methods and is based on the rotation of contour technique. It is applied to πd elastic scattering with coupling to the NΔ channel. The position of the pole is compared with predictions based on Argand diagram and speed analysis. We find that the conventional methods are unreliable if the pole is further from the real axis than the Δ resonance pole.

  6. Tent-Poles of the Bestseller

    DEFF Research Database (Denmark)

    Jensen, Thessa; Vistisen, Peter

    2013-01-01

    This article proposes a framework for understanding and analysing how the passive audience of a media event turns into active stakeholders. The starting point is the cross-media content quadrant (Jensen and Vistisen, 2012), which shows how the producer’s control is distributed on social media pla...... platforms, while storytelling evolves around a tent-pole, for example, a bestseller or blockbuster. To further explain how the audience engages, a three-step rhetoric model largely based on Bitzer (1998) and Tolkien (1971) is developed and explained....

  7. Inhibition of decay fungi using cotton cellulose hydrolysis as a model for wood decay

    Science.gov (United States)

    Frederick. Green

    2000-01-01

    Environmental pressures to replace chromium and arsenic in fixed waterborne preservatives have been increasing. Potential inhibitors of brown-, white- and soft-rot fungi need to be evaluated as alternative preservatives by screening and testing in, in vitro model systems. This paper reports the inhibition of cellulose depolymerization and weight loss of selected decay...

  8. Modeling corewood-outerwood transition in loblolly pine using wood specific gravity

    Science.gov (United States)

    Christian R. Mora; H. Lee Allen; Richard F. Daniels; Alexander Clark

    2007-01-01

    A modified logistic function was used for modeling specific-gravity profiles obtained from X-ray densitometry analysis in 675 loblolly pine (Pinus taeda L.) trees in four regeneration trials. Trees were 21 or 22 years old at the time of the study. The function was used for demarcating corewood, transitional, and outerwood zones. Site and silvicultural effects were...

  9. The dynamic of annual carbon allocation to wood in European forests is consistent with a combined source-sink limitation of growth: implications for modelling

    Science.gov (United States)

    Guillemot, J.; Martin-StPaul, N. K.; Dufrêne, E.; François, C.; Soudani, K.; Ourcival, J. M.; Delpierre, N.

    2015-02-01

    The extent to which forest growth is limited by carbon (C) supply (source control) or by cambial activity (sink control) will condition the response of trees to global changes. However, the physiological processes responsible for the limitation of forest growth are still under debate. The aim of this study is to evaluate the key drivers of the annual carbon allocation to wood along large soil and climate regional gradients in five tree species representative of the main European forest biomes (Fagus sylvatica, Quercus petraea, Quercus ilex, Quercus robur and Picea abies). Combining field measurements and process-based simulations at 49 sites (931 site-years), we assessed the stand biomass growth dependences at both inter-site and inter-annual scales. Specifically, the relative influence of forest C balance (source control), direct environmental control (water and temperature controls of sink activity) and allocation adjustments related to age, past climate conditions, competition intensity and soil nutrient availability on growth were quantified. The inter-site variability in stand C allocation to wood was predominantly driven by an age-related decline. The direct control of temperature or water stress on sink activity (i.e. independently from their effects on C supply) exerted a strong influence on the annual stand woody growth in all the species considered, including deciduous temperate species. The lagged effect of the past environment conditions was a significant driver of the annual C allocation to wood. Carbon supply appeared to strongly limit growth only in deciduous temperate species. We provide an evaluation of the spatio-temporal dynamics of annual carbon allocation to wood in European forests. Our study supports the premise that European forest growth is under a complex control including both source and sink limitations. The relative influences of the different growth drivers strongly vary across years and spatial ecological gradients. We suggest a

  10. Mechanical behaviour of cross-country ski racing poles during double poling.

    Science.gov (United States)

    Stöggl, Thomas; Karlöf, Lars

    2013-11-01

    The purpose of this study was to evaluate the behaviour of cross-country ski poles during double poling on a treadmill using three-dimensional kinematics. The results were compared with standard laboratory tests of the pole manufacturers. A total of 18 skiers were analysed at two speeds (85% and 95% of the maximal speed) at grades of 1.5% and 7%. Variables describing cycle characteristics, bending stiffness, bending behaviour, and trajectories of the pole markers were analysed. Triangular-shaped poles demonstrated the greatest stiffness and lowest variability in maximal bending. Softer poles demonstrated greater variability in bending behaviour and lost ground contact at high skiing speeds, which for some skiers resulted in failure to complete high-speed tests. Considerable variations in pole behaviour for similar poles between skiers were observed, which might be attributed to differences in technique, indicating that mechanical properties of the poles did not exclusively determine pole behaviour in the dynamic situation. The greatest magnitude of pole bending was in the middle part of the pole, which differed from the standard static pole analysis of the manufacturer. Increases in grade demonstrated the greatest effect on pole bending. Distinct differences from the pole manufacturers' laboratory measures were apparent, suggesting that basic pole testing might be adapted.

  11. 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 ...

  12. Inter-comparison of source apportionment models for the estimation of wood burning aerosols during wintertime in an Alpine city (Grenoble, France

    Directory of Open Access Journals (Sweden)

    O. Favez

    2010-01-01

    Full Text Available The emission of organic aerosols (OA in the ambient air by residential wood burning is nowadays a subject of great scientific concern and a growing number of studies aim at apportioning the influence of such emissions on urban air quality. In the present study, results obtained using two commonly-used source apportionment models, i.e., Chemical Mass Balance (CMB, performed with off-line filter measurements and Positive Matrix Factorization (PMF, applied to aerosol mass spectrometer measurements, as well as using the recently-proposed aethalometer model (based on the measurement of the aerosol light absorption at different wavelengths are inter-compared. This work is performed using field data obtained during the winter season (14 to 30 January 2009 at an urban background site of a French Alpine city (Grenoble. Converging results from the different models indicate a major contribution of wood burning organic aerosols (OMwb to the organic fraction, with mean OMwb contributions to total OA of about 67%, 60% and 38% for the CMB, the aethalometer and the AMS-PMF models, respectively. Quantitative discrepancies might notably be due to the overestimation of OMwb calculated by the CMB due to the loss of semi-volatile compounds from sources to receptor site, as well as to the accounting of oxidized primary wood burning organic (OPOAwb aerosols within the Oxygenated Organic Aerosol (OOA PMF-factor. This OOA factor accounts on average for about 50% of total OM, while non-combustion sources contribute to about 25% and 28% of total OM according to the CMB and aethalometer models, respectively. Each model suggests a mean contribution of fossil fuel emissions to total OM of about 10%. A good agreement is also obtained for the source apportionment of elemental carbon (EC by both the CMB and aethalometer models, with fossil fuel emissions representing on average more than 80% of total EC.

  13. Advances and expectations of study on wood rheology

    Institute of Scientific and Technical Information of China (English)

    马远荣; 罗迎社; 李贤军

    2008-01-01

    By studying and summarizing the characteristics of wood rheology,the mathematic models of creep and mechano-sorptive creep of wood were analyzed.Rheology behaviors in process,especially drying stress and deformation set were discussed.Application of wood rheology in woodcraft process was elaborated and the research prospects and orientation were forecasted.

  14. Fire retardants for wood

    Directory of Open Access Journals (Sweden)

    Vlatka Jirouš-Rajković

    2009-06-01

    Full Text Available Along with many advantages, wood as traditional building material also has some disadvantages. One of them is the flammability. The most usual way to improve the fire performance of wood is by treating it with fire retardants that can be applied to wood composite products during manufacture, pressure impregnated into solid wood or wood products or added as a paint or surface coating. Fire retardants are formulated to control ignition, flame spread on the wood surface and to reduce the amount of heat released from wood. Fire retardants cannot make wood non combustible. According to the European reaction-to-fire “Euroclasses”classification system for construction products, wood treated with fire retardant can meet the requirements of Euroclass B, whereas ordinary wood products typically fall into class D. This article attempts to bring together information related to the burning of wood, fire performance of wood, types of fire retardants and mechanism of fire retardancy. Fire retardant coatings and chemical impregnation by pressure-treating are described separately.

  15. 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 (

  16. 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.

  17. Comparison of ultrasonic with stirrer performance for removal of sunset yellow (SY) by activated carbon prepared from wood of orange tree: Artificial neural network modeling

    Science.gov (United States)

    Ghaedi, A. M.; Ghaedi, M.; Karami, P.

    2015-03-01

    The present work focused on the removal of sunset yellow (SY) dye from aqueous solution by ultrasound-assisted adsorption and stirrer by activated carbon prepared from wood of an orange tree. Also, the artificial neural network (ANN) model was used for predicting removal (%) of SY dye based on experimental data. In this study a green approach was described for the synthesis of activated carbon prepared from wood of an orange tree and usability of it for the removal of sunset yellow. This material was characterized using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The impact of variables, including initial dye concentration (mg/L), pH, adsorbent dosage (g), sonication time (min) and temperature (°C) on SY removal were studied. Fitting the experimental equilibrium data of different isotherm models such as Langmuir, Freundlich, Temkin and Dubinin-Radushkevich models display the suitability and applicability of the Langmuir model. Analysis of experimental adsorption data by different kinetic models including pseudo-first and second order, Elovich and intraparticle diffusion models indicate the applicability of the second-order equation model. The adsorbent (0.5 g) is applicable for successful removal of SY (>98%) in short time (10 min) under ultrasound condition.

  18. Comparison of ultrasonic with stirrer performance for removal of sunset yellow (SY) by activated carbon prepared from wood of orange tree: artificial neural network modeling.

    Science.gov (United States)

    Ghaedi, A M; Ghaedi, M; Karami, P

    2015-03-05

    The present work focused on the removal of sunset yellow (SY) dye from aqueous solution by ultrasound-assisted adsorption and stirrer by activated carbon prepared from wood of an orange tree. Also, the artificial neural network (ANN) model was used for predicting removal (%) of SY dye based on experimental data. In this study a green approach was described for the synthesis of activated carbon prepared from wood of an orange tree and usability of it for the removal of sunset yellow. This material was characterized using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The impact of variables, including initial dye concentration (mg/L), pH, adsorbent dosage (g), sonication time (min) and temperature (°C) on SY removal were studied. Fitting the experimental equilibrium data of different isotherm models such as Langmuir, Freundlich, Temkin and Dubinin-Radushkevich models display the suitability and applicability of the Langmuir model. Analysis of experimental adsorption data by different kinetic models including pseudo-first and second order, Elovich and intraparticle diffusion models indicate the applicability of the second-order equation model. The adsorbent (0.5g) is applicable for successful removal of SY (>98%) in short time (10min) under ultrasound condition. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. Iron Pole Shape Optimization of IPM Motors Using an Integrated Method

    Directory of Open Access Journals (Sweden)

    JABBARI, A.

    2010-02-01

    Full Text Available An iron pole shape optimization method to reduce cogging torque in Interior Permanent Magnet (IPM motors is developed by using the reduced basis technique coupled by finite element and design of experiments methods. Objective function is defined as the minimum cogging torque. The experimental design of Taguchi method is used to build the approximation model and to perform optimization. This method is demonstrated on the rotor pole shape optimization of a 4-poles/24-slots IPM motor.

  20. 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.

  1. Landau pole in the pyramid scheme

    Science.gov (United States)

    Banks, Tom; Fortin, Jean-François; Kathrein, Scott

    2010-12-01

    We revisit the problem of the hidden sector Landau pole in the pyramid scheme. There is a fixed line in the plane of hidden sector gauge coupling and Yukawa couplings between the trianon fields. We postulate that the couplings flow to this line, at a point where the hidden sector gauge coupling is close to the strong coupling edge of its perturbative regime. Below the masses of the heavier trianons, the model quickly flows to a confining NF=NC=3 supersymmetric gauge theory, as required by phenomenological considerations. We study possible discrete R symmetries, which guarantee, among other things, that the basin of attraction of the fixed line has full codimension in the space of R-allowed couplings. The Yukawa couplings required to get the fixed line violate the pyrma-baryon symmetries we invoked in previous work to find a dark matter candidate. Omitting one of them, we have a dark matter candidate, and an acceptable renormalization group flow down from the unification scale, if the confinement scale of the hidden sector group is lowered from 5 to 2 TeV. However, we cannot find anomaly-free symmetries, which guarantee a set of pyrma-baryon violating couplings that eliminate the Landau pole, but do not allow a supersymmetry preserving vacuum of the model. We can do this with only one pyrma-baryon violating coupling, but this lowers the confinement scale to 900 GeV, which may already be ruled out due to light hidden sector baryons.

  2. Modeling of Compressive Strength Parallel to Grain of Heat Treated Scotch Pine (Pinus sylvestris L. Wood by Using Artificial Neural Network

    Directory of Open Access Journals (Sweden)

    Fatih Yapıcı

    2016-01-01

    Full Text Available In this study, the compressive strength of heat treated Scotch Pine was modeled using artificial neural network. The compressive strength (CS value parallel to grain was determined after exposing the wood to heat treatment at temperature of 130, 145, 160, 175, 190 and 205ºC for 3, 6, 9, 12 hours. The experimental data was evaluated by using multiple variance analysis. Secondly, the effect of heat treatment on the CS of samples was modeled by using artificial neural network (ANN.

  3. Is it possible to reduce the knee joint compression force during level walking with hiking poles?

    Science.gov (United States)

    Jensen, S B; Henriksen, M; Aaboe, J; Hansen, L; Simonsen, E B; Alkjaer, T

    2011-12-01

    Walking with hiking poles has become a popular way of exercising. Walking with poles is advocated as a physical activity that significantly reduces the loading of the hip, knee and ankle joints. We have previously observed that pole walking does not lead to a reduction of the load on the knee joint. However, it is unclear whether an increased force transmitted through the poles can reduce the load on the knee joint. Thus, the purpose of the present study was to investigate if an increased load transmitted through the arms to the poles could reduce the knee joint compression force during level walking with poles. We hypothesized that an increased pole force would result in a reduction of the knee joint compression force. Gait analyses from 10 healthy subjects walking with poles were obtained. The pole force was measured simultaneously during the gait analyses. The knee joint compression forces were estimated by using a biomechanical knee joint model. The results showed that the subjects were able to increase the pole force by 2.4 times the normal pole force. However, this did not lead to a reduction in the knee joint compressive force and we rejected our hypothesis. In conclusion, the use of poles during level walking does not seem to reduce knee joint compressive loads. However, it is possible that the use of poles in other populations (e.g. osteoarthritis patients) and in terrain would unload the knee joint. This should be investigated in the future. © 2010 John Wiley & Sons A/S.

  4. The North Ecliptic Pole Supercluster

    OpenAIRE

    Mullis, C. R.; Henry, J. P.; Gioia, I. M.; Boehringer, H.; Briel, U. G.; Voges, W.; Huchra, J. P.

    2001-01-01

    We have used the ROSAT All-Sky Survey to detect a known supercluster at z=0.087 in the North Ecliptic Pole region. The X-ray data greatly improve our understanding of this supercluster's characteristics, approximately doubling our knowledge of the structure's spatial extent and tripling the cluster/group membership compared to the optical discovery data. The supercluster is a rich structure consisting of at least 21 galaxy clusters and groups, 12 AGN, 61 IRAS galaxies, and various other objec...

  5. a New Ediacaran Pole from Easternmost Baltica

    Science.gov (United States)

    Meert, J. G.; Levashova, N. M.; Kuznetsov, N. B.; Sergeeva, N. D.; Golovanova, I. V.; Danukalov, K. N.; Bazhenov, M. L.

    2011-12-01

    Ediacaran paleogeography is notoriously messy due to equally confusing paleomagnetic data from both Laurentia and Baltica. Ediacaran (~Vendian) rocks have been studied from several localities from Baltica, but the so far published poles can be used to place the Baltic craton at nearly any latitude and orientation [Meert et al., 2007]. At the same time, it is challenging to understand the paleogeography of the Ediacaran world given all the biologic, climatic and tectonic changes during the time interval from 635-542 Ma. We present preliminary paleomagnetic and geochronological data from (late?) Ediacaran sediments from the deformed (low metamorphic grade) peri-Uralian margin of Baltica. We successfully isolated a dual-polarity high-temperature component from eleven sites; the primary origin of this remanence is strongly supported by a positive reversal test (class B). The corresponding paleomagnetic pole is in close agreement with the coeval results from the Winter Coast of northern Baltica [Popov et al., 2002; 2005; Iglesia Llanos et al., 2005], despite a ~1600 km separation between two study areas. These data jointly indicate a very low (<10 degrees N or S) paleolatitude for eastern Baltica in Ediacaran time. Paleogeographic implications of these new data will be discussed in the context of Ediacaran-Cambrian tectonic models. This study is supported by RFBR grant 11-05-00037 and NSF grant EAR11-19038.

  6. Dynamics of Enceladus South Pole Ejecta

    Science.gov (United States)

    Makuch, Martin; Schmidt, J.; Spahn, F.

    2007-10-01

    The Saturnian moon Enceladus was recently found to be a potent source of gas and dust particles. There was an active region observed on the south pole of Enceladus with jets spraying material in the space. The ejected dust particles are considered to be the main source of the faint E ring. In our work we investigate the long-term dynamics of icy particles ejected from the south pole of Enceladus. The motion of the ejected grains, being subject to many perturbation forces, strongly depends on particle properties (e.g. size, charge etc.). We study the resulting spatial distribution of particles in the E ring. Primarily we focus on the structure of the ring in the vicinity of Enceladus. In our study we also concentrated on processes limiting particle lifetime. These are mainly collisions with Enceladus and other Saturnian satellites or main ring, as well as the sputtering of particles by plasma ions bombardment. Modeling the equilibrium between particle sources and sinks we found the size distribution which is expected to be observed in the E ring.

  7. Modeling the influence of alternative forest management scenarios on wood production and carbon storage: A case study in the Mediterranean region.

    Science.gov (United States)

    Bottalico, Francesca; Pesola, Lucia; Vizzarri, Matteo; Antonello, Leonardo; Barbati, Anna; Chirici, Gherardo; Corona, Piermaria; Cullotta, Sebastiano; Garfì, Vittorio; Giannico, Vincenzo; Lafortezza, Raffaele; Lombardi, Fabio; Marchetti, Marco; Nocentini, Susanna; Riccioli, Francesco; Travaglini, Davide; Sallustio, Lorenzo

    2016-01-01

    Forest ecosystems are fundamental for the terrestrial biosphere as they deliver multiple essential ecosystem services (ES). In environmental management, understanding ES distribution and interactions and assessing the economic value of forest ES represent future challenges. In this study, we developed a spatially explicit method based on a multi-scale approach (MiMoSe-Multiscale Mapping of ecoSystem services) to assess the current and future potential of a given forest area to provide ES. To do this we modified and improved the InVEST model in order to adapt input data and simulations to the context of Mediterranean forest ecosystems. Specifically, we integrated a GIS-based model, scenario model, and economic valuation to investigate two ES (wood production and carbon sequestration) and their trade-offs in a test area located in Molise region (Central Italy). Spatial information and trade-off analyses were used to assess the influence of alternative forest management scenarios on investigated services. Scenario A was designed to describe the current Business as Usual approach. Two alternative scenarios were designed to describe management approaches oriented towards nature protection (scenario B) or wood production (scenario C) and compared to scenario A. Management scenarios were simulated at the scale of forest management units over a 20-year time period. Our results show that forest management influenced ES provision and associated benefits at the regional scale. In the test area, the Total Ecosystem Services Value of the investigated ES increases 85% in scenario B and decreases 82% in scenario C, when compared to scenario A. Our study contributes to the ongoing debate about trade-offs and synergies between carbon sequestration and wood production benefits associated with socio-ecological systems. The MiMoSe approach can be replicated in other contexts with similar characteristics, thus providing a useful basis for the projection of benefits from forest

  8. Quantifying and modelling the effects of environmental factors on wood properties of Eucalyptus grandis in South Africa

    CSIR Research Space (South Africa)

    Naidoo, Sasha

    2011-03-01

    Full Text Available the effects of environmental factors on wood properties of Eucalyptus grandis in South Africa by Sasha Naidoo Submitted in fulfilment of the academic requirements for the degree of Doctor of Philosophy In the School of Biological... - PLAGIARISM I, Sasha Naidoo declare that 1. The research reported in this thesis, except where otherwise indicated, is my original research. 2. This thesis has not been submitted for any degree or examination at any other university. 3...

  9. The North Ecliptic Pole Supercluster

    CERN Document Server

    Mullis, C R; Gioia, I M; Böhringer, H; Briel, U G; Voges, W; Huchra, J P

    2001-01-01

    We have used the ROSAT All-Sky Survey to detect a known supercluster at z=0.087 in the North Ecliptic Pole region. The X-ray data greatly improve our understanding of this supercluster's characteristics, approximately doubling our knowledge of the structure's spatial extent and tripling the cluster/group membership compared to the optical discovery data. The supercluster is a rich structure consisting of at least 21 galaxy clusters and groups, 12 AGN, 61 IRAS galaxies, and various other objects. A majority of these components were discovered with the X-ray data, but the supercluster is also robustly detected in optical, IR, and UV wavebands. Extending 129 x 102 x 67 (1/h50 Mpc)^3, the North Ecliptic Pole Supercluster has a flattened shape oriented nearly edge-on to our line-of-sight. Owing to the softness of the ROSAT X-ray passband and the deep exposure over a large solid angle, we have detected for the first time a significant population of X-ray emitting galaxy groups in a supercluster. These results demon...

  10. Ising Spectroscopy II: Particles and poles at T>Tc

    CERN Document Server

    Zamolodchikov, Alexander

    2013-01-01

    I discuss particle content of the Ising field theory (the scaling limit of the Ising model in a magnetic field), in particular the evolution of its mass spectrum under the change of the scaling parameter. I consider both real and pure imaginary magnetic field. Here I address the high-temperature regime, where the spectrum of stable particles is relatively simple (there are from one to three particles, depending on the parameter). My goal is to understand analytic continuations of the masses to the domain of the parameter where they no longer exist as the stable particles. I use the natural tool -- the $2\\to 2$ elastic scattering amplitude, with its poles associated with the stable particles, virtual and resonance states in a standard manner. Concentrating attention on the "real" poles (those corresponding to stable and virtual states) I propose a scenario on how the pattern of the poles evolves from the integrable point $T=T_c,\\ H\

  11. A HIGH PERFORMANCE OPTIMIZATION TECHNIQUE FOR POLE BALANCING PROBLEM

    Directory of Open Access Journals (Sweden)

    Bahadır KARASULU

    2008-02-01

    Full Text Available High performance computing techniques can be used effectively for solution of the complex scientific problems. Pole balancing problem is a basic benchmark tool of robotic field, which is an important field of Artificial Intelligence research areas. In this study, a solution is developed for pole balancing problem using Artificial Neural Network (ANN and high performance computation technique. Algorithm, that basis of the Reinforcement Learning method which is used to find the force of pole's balance, is transfered to parallel environment. In Implementation, C is preferred as programming language and Message Passing Interface (MPI is used for parallel computation technique. Self–Organizing Map (SOM ANN model's neurons (artificial neural nodes and their weights are distributed to six processors of a server computer which equipped with each quad core processor (total 24 processors. In this way, performance values are obtained for different number of artificial neural nodes. Success of method based on results is discussed.

  12. Global plate tectonics and the secular motion of the pole

    Science.gov (United States)

    Soler, T.

    1977-01-01

    Astronomical data compiled during the last 70 years by the international organizations providing the coordinates of the instantaneous pole clearly shows a persistent drift of the mean pole. The differential contributions to the earth's second-order tensor of inertia were obtained and applied, resulting in no significant displacement of the earth's principal axis. In view of the above, the effect that theoretical geophysical models for absolute plate velocities may have on an apparent displacement of the mean pole as a consequence of station drifting was analyzed. The investigation also reports new values for the crustal tensor of inertia (assuming an ellipsoidal earth) and the orientation of its axis of figure, reopening the old speculation of a possible sliding of the whole crustover the upper mantle, including the supporting geophysical and astronomic evidence.

  13. PLANNING THE QUALITY OF LIFE FOR TIMISOARA GROWTH POLE

    Directory of Open Access Journals (Sweden)

    Cătălina-Livia POPA

    2014-06-01

    Full Text Available This paper aims to show that planning the quality of life at local level through economic development can be a new approach for policy makers and community in improving quality of life. In this purpose, the Quality Function Deployment (QFD model will be use to planning the quality of life and to identify the main directions of economic development to support improving the quality of life at the level of Timisoara Growth Pole from Romania. The dimensions of quality of life are analyzed starting from the point of view of inhabitants. The results include a new approach in which the dimensions of quality of life are the key element that orients economic development in order to improve the quality of life of human being. The case study results refer to the main elements of quality of life at Timisoara Growth Pole and the relevant directions of economic development to improve the quality of life for Timisoara Growth Pole.

  14. Multichannel Anomaly of the Resonance Pole Parameters Resolved

    OpenAIRE

    Ceci, Sasa; Stahov, Jugoslav; Svarc, Alfred; Watson, Shon; Zauner, Branimir

    2006-01-01

    Inspired by anomalies which the standard scattering matrix pole-extraction procedures have produced in a mathematically well defined coupled-channel model, we have developed a new method based solely on the assumption of partial-wave analyticity. The new method is simple and applicable not only to theoretical predictions but to the empirical partial-wave data as well. Since the standard pole-extraction procedures turn out to be the lowest-order term of the proposed method the anomalies are un...

  15. Multichannel Anomaly of the Resonance Pole Parameters Resolved

    CERN Document Server

    Ceci, S; Svarc, A; Watson, S; Zauner, B; Ceci, Sasa; Stahov, Jugoslav; Svarc, Alfred; Watson, Shon; Zauner, Branimir

    2006-01-01

    Inspired by anomalies which the standard scattering matrix pole-extraction procedures have produced in a mathematically well defined coupled-channel model, we have developed a new method based solely on the assumption of partial-wave analyticity. The new method is simple and applicable not only to theoretical predictions but to the empirical partial-wave data as well. Since the standard pole-extraction procedures turn out to be the lowest-order term of the proposed method the anomalies are understood and resolved.

  16. Analysis of U.S. household wood energy consumption: 1967-2009

    Science.gov (United States)

    Nianfu. Song; Francisco X. Aguilar; Stephen R. Shifley; Michael E. Goerndt

    2012-01-01

    The residential sector consumes about 23% of the energy derived from wood (wood energy) in the U.S. An estimated error correction model with data from 1967 to 2009 suggests that residential wood energy consumption has declined by an average 3% per year in response to technological progress, urbanization, accessibility of non-wood energy, and other factors associated...

  17. Modeling strength loss in wood by chemical composition. Part I, An individual component model for southern pine

    Science.gov (United States)

    J. E. Winandy; P. K. Lebow

    2001-01-01

    In this study, we develop models for predicting loss in bending strength of clear, straight-grained pine from changes in chemical composition. Although significant work needs to be done before truly universal predictive models are developed, a quantitative fundamental relationship between changes in chemical composition and strength loss for pine was demonstrated. In...

  18. Delineating pMDI model reactions with loblolly pine via solution-state NMR spectroscopy. Part 2, Non-catalyzed reactions with the wood cell wall

    Science.gov (United States)

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

    2011-01-01

    Solution-state NMR provides a powerful tool to observe the presence or absence of covalent bonds between wood and adhesives. Finely ground wood can be dissolved in an NMR compatible solvent system containing dimethylsulfoxide-d6 and N-methylimidazole-d6, in which the wood polymers remain largely intact. High-resolution...

  19. Factors controlling large-wood transport in a mountain river

    Science.gov (United States)

    Ruiz-Villanueva, Virginia; Wyżga, Bartłomiej; Zawiejska, Joanna; Hajdukiewicz, Maciej; Stoffel, Markus

    2016-11-01

    As with bedload transport, wood transport in rivers is governed by several factors such as flow regime, geomorphic configuration of the channel and floodplain, or wood size and shape. Because large-wood tends to be transported during floods, safety and logistical constraints make field measurements difficult. As a result, direct observation and measurements of the conditions of wood transport are scarce. This lack of direct observations and the complexity of the processes involved in wood transport may result in an incomplete understanding of wood transport processes. Numerical modelling provides an alternative approach to addressing some of the unknowns in the dynamics of large-wood in rivers. The aim of this study is to improve the understanding of controls governing wood transport in mountain rivers, combining numerical modelling and direct field observations. By defining different scenarios, we illustrate relationships between the rate of wood transport and discharge, wood size, and river morphology. We test these relationships for a wide, multithread reach and a narrower, partially channelized single-thread reach of the Czarny Dunajec River in the Polish Carpathians. Results indicate that a wide range of quantitative information about wood transport can be obtained from a combination of numerical modelling and field observations and from document contrasting patterns of wood transport in single- and multithread river reaches. On the one hand, log diameter seems to have a greater importance for wood transport in the multithread channel because of shallower flow, lower flow velocity, and lower stream power. Hydrodynamic conditions in the single-thread channel allow transport of large-wood pieces, whereas in the multithread reach, logs with diameters similar to water depth are not being moved. On the other hand, log length also exerts strong control on wood transport, more so in the single-thread than in the multithread reach. In any case, wood transport strongly

  20. Solvent cleaning of pole transformers containing PCB contaminated insulating oil.

    Science.gov (United States)

    Kanbe, H; Shibuya, M

    2001-01-01

    In 1989, it was discovered that the recycled insulation oil in pole transformers for electric power supply was contaminated with trace amounts of polychlorinated biphenyls (PCBs; maximum 50 mg-PCB/kg-insulation oil). In order to remove the PCBs from transformer components using n-hexane as a solvent, we investigated the relationship between progressive stages of dismantling and cleaning results. The results are summarized as follows: (1) Based on the cleaning test results, we made an estimate of the residual PCB amount on iron and copper components. By dismantling the test pole transformers into the "iron core and coil portion" and cleaning the components, we achieved a residual PCB amount that was below the limit of detection (0.05 mg-PCB/kg-material). To achieve a residual PCB amount below the limit of detection for the transformer paper component, it was necessary to cut the paper into pieces smaller than 5 mm. We were unable to achieve a residual PCB amount below the limit of detection for the wood component. (2) Compared to Japan's stipulated limited concentration standard values for PCBs, the results of the cleaning test show that cleaning iron or copper components with PCBs only on their surface with the solvent n-hexane will satisfy the limited concentration standard values when care is taken to ensure the component surfaces have adequate contact with the cleaning solvent.

  1. Lignification and tension wood.

    Science.gov (United States)

    Pilate, Gilles; Chabbert, Brigitte; Cathala, Bernard; Yoshinaga, Arata; Leplé, Jean-Charles; Laurans, Françoise; Lapierre, Catherine; Ruel, Katia

    2004-01-01

    Hardwood trees are able to reorient their axes owing to tension wood differentiation. Tension wood is characterised by important ultrastructural modifications, such as the occurrence in a number of species, of an extra secondary wall layer, named gelatinous layer or G-layer, mainly constituted of cellulose microfibrils oriented nearly parallel to the fibre axis. This G-layer appears directly involved in the definition of tension wood mechanical properties. This review gathers the data available in the literature about lignification during tension wood formation. Potential roles for lignin in tension wood formation are inferred from biochemical, anatomical and mechanical studies, from the hypotheses proposed to describe tension wood function and from data coming from new research areas such as functional genomics.

  2. Effects of slotting and unipolar flux on magnetic pull in a two-pole induction motor with an extra four-pole stator winding

    Energy Technology Data Exchange (ETDEWEB)

    Sinervo, A.

    2013-06-01

    This thesis is about the radial magnetic forces between the rotor and stator in twopole induction machines. The magnetic forces arise from rotor eccentricity. The asymmetric air-gap makes the flux density on one side of the rotor stronger than on the opposite side. This produces magnetic pull. The magnetic flux density distribution in the air-gap can be expressed with spatial harmonics, i.e. flux densities with different pole-pair numbers. In two-pole machines, the main part of the magnetic force is produced by the interaction of two- and fourpole flux unless the four-pole flux is damped by parallel paths in the stator winding or an extra four-pole stator winding. The rest of the force comes from the interaction of two-pole and unipolar flux and from the higher harmonics of the air-gap flux of which the slot harmonics are a major part. The force caused by the higher harmonics and the unipolar flux is studied in the case where a four-pole stator winding is used to reduce the four-pole flux. The higher harmonics are found to produce, in addition to the traditional unbalanced magnetic pull, a force similar to the effect of the unipolar flux and the two can be distinguished only by measuring the unipolar flux. In measurements at various operation points, the higher harmonics are found to produce much more force than the unipolar flux and two-pole flux but the unipolar flux is still significant. The four-pole winding also is used to actively control the four-pole flux and the magnetic forces. Designing the controller requires a low order model of the system. Such a model is derived and the effect of the slot harmonics and the unipolar flux are included in the model. Different measurements techniques and methods are presented to identify and validate the control model. The operation point dependence of the system dynamics is studied via measurements. All results are obtained from a 30 kW test motor. The rotor of the test machine has a long flexible shaft on external

  3. Minimizing waste (off-cuts using cutting stock model: The case of one dimensional cutting stock problem in wood working industry

    Directory of Open Access Journals (Sweden)

    Gbemileke A. Ogunranti

    2016-09-01

    Full Text Available Purpose: The main objective of this study is to develop a model for solving the one dimensional cutting stock problem in the wood working industry, and develop a program for its implementation. Design/methodology/approach: This study adopts the pattern oriented approach in the formulation of the cutting stock model. A pattern generation algorithm was developed and coded using Visual basic.NET language. The cutting stock model developed is a Linear Programming (LP Model constrained by numerous feasible patterns. A LP solver was integrated with the pattern generation algorithm program to develop a one - dimensional cutting stock model application named GB Cutting Stock Program. Findings and Originality/value: Applying the model to a real life optimization problem significantly reduces material waste (off-cuts and minimizes the total stock used. The result yielded about 30.7% cost savings for company-I when the total stock materials used is compared with the former cutting plan. Also, to evaluate the efficiency of the application, Case I problem was solved using two top commercial 1D-cutting stock software.  The results show that the GB program performs better when related results were compared. Research limitations/implications: This study round up the linear programming solution for the number of pattern to cut. Practical implications: From Managerial perspective, implementing optimized cutting plans increases productivity by eliminating calculating errors and drastically reducing operator mistakes. Also, financial benefits that can annually amount to millions in cost savings can be achieved through significant material waste reduction. Originality/value: This paper developed a linear programming one dimensional cutting stock model based on a pattern generation algorithm to minimize waste in the wood working industry. To implement the model, the algorithm was coded using VisualBasic.net and linear programming solver called lpsolvedll (dynamic

  4. Preliminary studies of Brazilian wood using different radioisotopic sources

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho, Gilberto; Silva, Leonardo Gondim de Andrade e, E-mail: gcarval@ipen.br, E-mail: ftgasilva@gmail.com [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2013-07-01

    Due to availability and particular features, wood was one of the first materials used by mankind with a wide variety of applications. It can be used as raw material for paper and cellulose manufacturing; in industries such as chemical, naval, furniture, sports goods, toys, and musical instrument; in building construction and in the distribution of electric energy. Wood has been widely researched; therefore, wood researchers know that several aspects such as temperature, latitude, longitude, altitude, sunlight, soil, and rainfall index interfere with the growth of trees. This behavior explains why average physical-chemical properties are important when wood is studied. The majority of researchers consider density to be the most important wood property because of its straight relationship with the physical and mechanical properties of wood. There are three types of wood density: basic, apparent and green. The apparent density was used here at 12% of moisture content. In this study, four different types of wood were used: 'freijo', 'jequetiba', 'muiracatiara' and 'ipe'. For wood density determination by non-conventional method, Am-241, Ba-133 and Cs-137 radioisotopic sources; a NaI scintillation detector and a counter were used. The results demonstrated this technique to be quick and accurate. By considering the nuclear parameters obtained as half value layers and linear absorption coefficients, Cs-137 radioisotopic source demonstrated to be the best option to be used for inspection of the physical integrity of electric wooden poles and live trees for future works. (author)

  5. Inventory of contaminants in waste wood; Inventering av foeroreningar i returtrae

    Energy Technology Data Exchange (ETDEWEB)

    Jermer, Joeran; Ekvall, Annika; Tullin, Claes [Swedish National Testing and Research Inst., Boraas (Sweden)

    2001-03-01

    problems. Metal objects of zinc, brass and aluminium are considered to be particularly troublesome as they may plug primary air openings. PVC residues may cause considerably higher levels of chlorine in waste wood. Chemical analyses indicate that the distribution in levels of impurities varies a lot between deliveries of waste wood. Difficulties to take representative samples probably contribute to this. The knowledge of the contents of different types of waste wood (surface treated wood, preservative-treated, panels, furniture etc) in the waste wood flow is only fragmentary. Most certainly, surface treated (painted, stained etc) wood constitute the highest proportion. Preservative-treated wood, with the exception of railway sleepers and poles, is estimated to constitute approximately 5% of the waste wood flow in Sweden today and the next 25-30 years. The study has confirmed previous studies that waste wood contains a substantial proportion of fine fraction. 25-40% of the waste wood passed a sieve with a mesh size of 4 mm at screening trials. Chemical analyses indicated that the fine fraction will be the main contributor to contaminants of potassium, chlorine, sodium, zinc and lead. Further studies are suggested to focus on sorting, preparation, classification and quality assurance of waste wood.

  6. New pole placement algorithm - Polynomial matrix approach

    Science.gov (United States)

    Shafai, B.; Keel, L. H.

    1990-01-01

    A simple and direct pole-placement algorithm is introduced for dynamical systems having a block companion matrix A. The algorithm utilizes well-established properties of matrix polynomials. Pole placement is achieved by appropriately assigning coefficient matrices of the corresponding matrix polynomial. This involves only matrix additions and multiplications without requiring matrix inversion. A numerical example is given for the purpose of illustration.

  7. Characterization of thermally poled germanosilicate thin films

    NARCIS (Netherlands)

    Ozcan, A.; Digonnet, M.J.F.; Kino, G.S.; Ay, F.; Aydinli, A.

    2004-01-01

    We report measurements of the nonlinearity profile of thermally poled low-loss germanosilicate films deposited on fused-silica substrates by PECVD, of interest as potential electro-optic devices. The profiles of films grown and poled under various conditions all exhibit a sharp peak similar to0.5 mu

  8. Macro Fiber Piezocomposite Actuator Poling Study

    Science.gov (United States)

    Werlink, Rudy J.; Bryant, Robert G.; Manos, Dennis

    2002-01-01

    The performance and advantages of Piezocomposite Actuators are to provide a low cost, in-situ actuator/sensor that is flexible, low profile and high strain per volt performance in the same plane of poled voltage. This paper extends reported data for the performance of these Macrofiber Composite (MFC) Actuators to include 4 progressively narrower Intedigitized electrode configurations with several line widths and spacing ratios. Data is reported for max free strain, average strain per applied volt, poling (alignment of the electric dipoles of the PZT ceramic) voltage vs. strain and capacitance, time to poling voltage 95% saturation. The output strain per volt progressively increases as electrode spacing decreases, with saturation occurring at lower poling voltages. The narrowest spacing ratio becomes prone to voltage breakdown or short circuits limiting the spacing width with current fabrication methods. The capacitance generally increases with increasing poling voltage level but has high sensitivity to factors such as temperature, moisture and time from poling which limit its usefulness as a simple indicator. The total time of applied poling voltage to saturate or fully line up the dipoles in the piezoceramic was generally on the order of 5-20 seconds. Less sensitivity to poling due to the applied rate of voltage increase over a 25 to 500 volt/second rate range was observed.

  9. Miks pole Eestis edukat keskklassi? / Heimar Lenk

    Index Scriptorium Estoniae

    Lenk, Heimar, 1946-

    2005-01-01

    Riigikogu liikme sõnul pole Eesti häda mitte rikaste rikkuses, vaid selles, et meil pole välja kujunenud keskklassi. Eestis puudub keskklass seetõttu, et rahvas on majanduslikult liialt kihistunud, tugevalt paremale kaldu poliitika on soodustanud vaid kitsa kildkonna rikastumist

  10. 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.

  11. Characterization of thermally poled germanosilicate thin films

    Science.gov (United States)

    Ozcan, A.; Digonnet, M. J. F.; Kino, G. S.; Ay, F.; Aydinli, A.

    2004-10-01

    We report measurements of the nonlinearity profile of thermally poled low-loss germanosilicate films deposited on fused-silica substrates by PECVD, of interest as potential electro-optic devices. The profiles of films grown and poled under various conditions all exhibit a sharp peak ~0.5 μm beneath the anode surface, followed by a weaker pedestal of approximately constant amplitude down to a depth of 13-16 μm, without the sign reversal typical of poled undoped fused silica. These features suggest that during poling, the films significantly slow down the injection of positive ions into the structure. After local optimization, we demonstrate a record peak nonlinear coefficient of ~1.6 pm/V, approximately twice as strong as the highest reliable value reported in thermally poled fused silica glass, a significant improvement that was qualitatively expected from the presence of Ge.

  12. Pole placement with constant gain output feedback

    Science.gov (United States)

    Sridhar, B.; Lindorff, D. P.

    1972-01-01

    Given a linear time invariant multivariable system with m inputs and p outputs, it was shown that p closed loop poles of the system can be preassigned arbitrarily using constant gain output feedback provided (A circumflex, B circumflex) is controllable. These data show that if (A circumflex, B circumflex, C circumflex) is controllable and observable, and Rank B circumflex = m, Rank C circumflex = p, then max (m,p) poles of the system can be assigned arbitarily using constant gain output feedback. Further, it is shown that in some cases more than max (m,p) poles can be arbitrarily assigned. A least square design technique is outlined to approximate the desired pole locations when it is not possible to place all the poles.

  13. Baryon transition form factors at the pole

    Science.gov (United States)

    Tiator, L.; Döring, M.; Workman, R. L.; Hadžimehmedović, M.; Osmanović, H.; Omerović, R.; Stahov, J.; Švarc, A.

    2016-12-01

    Electromagnetic resonance properties are uniquely defined at the pole and do not depend on the separation of the resonance from background or the decay channel. Photon-nucleon branching ratios are nowadays often quoted at the pole, and we generalize the considerations to the case of virtual photons. We derive and compare relations for nucleon to baryon transition form factors both for the Breit-Wigner and the pole positions. Using the MAID2007 and SAID SM08 partial wave analyses of pion electroproduction data, we compare the GM, GE, and GC form factors for the Δ (1232 ) resonance excitation at the Breit-Wigner resonance and pole positions up to Q2=5 GeV2 . We also explore the E /M and S /M ratios as functions of Q2. For pole and residue extraction, we apply the Laurent + Pietarinen method.

  14. Baryon transition form factors at the pole

    CERN Document Server

    Tiator, L; Workman, R L; Hadžimehmedović, M; Osmanović, H; Omerović, R; Stahov, J; Švarc, A

    2016-01-01

    Electromagnetic resonance properties are uniquely defined at the pole and do not depend on the separation of the resonance from background or the decay channel. Photon-nucleon branching ratios are nowadays often quoted at the pole, and we generalize the considerations to the case of virtual photons. We derive and compare relations for nucleon to baryon transition form factors both for the Breit-Wigner and the pole positions. Using the MAID2007 and SAID SM08 partial wave analyses of pion electroproduction data, we compare the $G_M$, $G_E$, and $G_C$ form factors for the $\\Delta(1232)$ resonance excitation at the Breit-Wigner resonance and pole positions up to $Q^2=5$ GeV$^2$. We also explore the $E/M$ and $S/M$ ratios as functions of $Q^2$. For pole and residue extraction, we apply the Laurent + Pietarinen method.

  15. Planar glass devices for efficient periodic poling

    DEFF Research Database (Denmark)

    Fage-Pedersen, Jacob; Jacobsen, Rune Shim; Kristensen, Martin

    2005-01-01

    We demonstrate that frequency-converting devices of high quality can be realised with glass poling. The devices, made with silica-on-silicon technology, are poled with periodic, embedded electrodes, and used for second-harmonic generation. We obtain precise control of the quasi phase-matching wav......We demonstrate that frequency-converting devices of high quality can be realised with glass poling. The devices, made with silica-on-silicon technology, are poled with periodic, embedded electrodes, and used for second-harmonic generation. We obtain precise control of the quasi phase......-matching wavelength and bandwidth, and a normalised conversion efficiency of 1.4×10-3 %/W/cm2 which, to our knowledge, is the highest obtained so far with periodic glass poling....

  16. Baryon transition form factors at the pole

    Energy Technology Data Exchange (ETDEWEB)

    Tiator, L.; Döring, M.; Workman, R. L.; Hadžimehmedović, M.; Osmanović, H.; Omerović, R.; Stahov, J.; Švarc, A.

    2016-12-01

    Electromagnetic resonance properties are uniquely defined at the pole and do not depend on the separation of the resonance from background or the decay channel. Photon-nucleon branching ratios are nowadays often quoted at the pole, and we generalize the considerations to the case of virtual photons. We derive and compare relations for nucleon to baryon transition form factors both for the Breit-Wigner and the pole positions. Using the MAID2007 and SAID SM08 partial wave analyses of pion electroproduction data, we compare the $G_M$, $G_E$, and $G_C$ form factors for the $\\Delta(1232)$ resonance excitation at the Breit-Wigner resonance and pole positions up to $Q^2=5$ GeV$^2$. We also explore the $E/M$ and $S/M$ ratios as functions of $Q^2$. For pole and residue extraction, we apply the Laurent + Pietarinen method.

  17. Mineralization of fossil wood

    NARCIS (Netherlands)

    Buurman, P.

    1972-01-01

    Several pieces of fossil wood have been analyzed with X-ray diffraction and were grouped on the basis of mineralogical composition. Various mineralizations were studied in thin sections and by means of the scanning electron microscope. Wood-opals appear to show a structure preservation that points t

  18. Wood supply and demand

    Science.gov (United States)

    Peter J. Ince; David B. McKeever

    2011-01-01

    At times in history, there have been concerns that demand for wood (timber) would be greater than the ability to supply it, but that concern has recently dissipated. The wood supply and demand situation has changed because of market transitions, economic downturns, and continued forest growth. This article provides a concise overview of this change as it relates to the...

  19. Heat sterilization of wood

    Science.gov (United States)

    Xiping Wang

    2010-01-01

    Two important questions should be considered in heat sterilizing solid wood materials: First, what temperature–time regime is required to kill a particular pest? Second, how much time is required to heat the center of any wood configuration to the kill temperature? The entomology research on the first question has facilitated the development of international standards...

  20. Parametric Analysis of Composite Reinforced Wood Tubes Under Axial Compression

    OpenAIRE

    Cabrero, J.; Heiduschke, A.; Haller, P. (P.)

    2010-01-01

    Wood tubes combine economy, an efficient use of the material and optimal structural performance. They can be optionally reinforced with technical fibers and/or textiles laminated to the outer wood surface. The paper presents the outcomes of a parametric study on the performance of wood reinforced tubes submitted to axial compression. Simple analytical models were applied to estimate the load-carrying capacity of the tubes and their failure mechanisms. Analytical and numerical models were deve...

  1. Holography with a Landau pole

    CERN Document Server

    Faedo, Anton F; Pantelidou, Christiana; Tarrio, Javier

    2016-01-01

    Holography for UV-incomplete gauge theories is important but poorly understood. A paradigmatic example is $d=4$, $\\mathcal{N}=4$ super Yang-Mills coupled to $N_f$ quark flavors, which possesses a Landau pole at a UV scale $\\Lambda_{LP}$. The dual gravity solution exhibits a UV singularity at a finite proper distance along the holographic direction. Despite this, holographic renormalization can be fully implemented via analytic continuation to an AdS solution. The presence of a UV cut-off manifests itself in several interesting ways. At energies $E \\ll \\Lambda_{LP}$ no pathologies appear, as expected from effective field theory. In contrast, at scales $E \\lesssim \\Lambda_{LP}$ the gravitational potential becomes repulsive, and at temperatures $T \\lesssim \\Lambda_{LP}$ the specific heat becomes negative. Although we focus on $\\mathcal{N}=4$ super Yang-Mills with flavor, our qualitative results apply to a much more general class of theories, since they only depend on the fact that the metric near the UV singular...

  2. Generalised pole-placement control of steam turbine speed

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez-del-Busto, R. [ITESM, Cuernavaca (Mexico). Div. de Ingenieria y Ciencias; Munoz, J. [ITESM, Xochimilco (Mexico). Div. de Ingenieria y Ciencias

    1996-12-31

    An application of a pole-placement self-tuning predictive control algorithm is developed to regulate speed of a power plant steam turbine model. Two types of system representation (CARMA and CARIMA) are used to test the control algorithm. Simulation results show that when using a CARMA model better results are produced. Two further comparisons are made when using a PI controller and a generalised predictive controller. (author)

  3. Feynman rules of higher-order poles in CHY construction

    Science.gov (United States)

    Huang, Rijun; Feng, Bo; Luo, Ming-xing; Zhu, Chuan-Jie

    2016-06-01

    In this paper, we generalize the integration rules for scattering equations to situations where higher-order poles are present. We describe the strategy to deduce the Feynman rules of higher-order poles from known analytic results of simple CHY-integrands, and propose the Feynman rules for single double pole and triple pole as well as duplex-double pole and triplex-double pole structures. We demonstrate the validation and strength of these rules by ample non-trivial examples.

  4. 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.

  5. MECHANICAL AND CHEMICAL MODIFICATION OF WOOD MATERIALS – COMPRESSED WOOD AND OXIDIZED CHARCOAL

    National Research Council Canada - National Science Library

    Vasily I. Patyakin; Uzum U. Sugaipov; Alexei R. Birman; Sergei M. Bazarov; Yuri N. Pilshikov; Andrei A. Spitsyn; Howard D. Mettee

    2008-01-01

    Mechanical compression and electrolyte infusion of wood, pyrolysis, and chemical activation of the resulting charcoals produced enhanced abilities to adsorb lead ion and benzene from model polluted water solutions. Iodine number (F...

  6. Estimates of black carbon and size-resolved particle number emission factors from residential wood burning based on ambient monitoring and model simulations.

    Science.gov (United States)

    Olivares, Gustavo; Ström, Johan; Johansson, Christer; Gidhagen, Lars

    2008-06-01

    In this paper we derive typical emission factors for coarse particulate matter (PM(10)), oxides of nitrogen (NO(x)), black carbon (BC), and number particle size distributions based on a combination of measurements and air quality dispersion modeling. The advantage of this approach is that the emission factors represent integrated emissions from several vehicle types and different types of wood stoves. Normally it is very difficult to estimate the total emissions in cities on the basis of laboratory measurements on single vehicles or stoves because of the large variability in conditions. The measurements were made in Temuco, Chile, between April 18 and June 15, 2005 at two sites. The first one was located in a residential area relatively far from major roads. The second site was located in a busy street in downtown Temuco where wood consumption is low. The measurements support the assumption that the monitoring sites represent the impact of different emission sources, namely traffic and residential wood combustion (RWC). Fitting model results to the available measurements, emission factors were obtained for PM(10) (RWC = 2160 +/- 100 mg/kg; traffic = 610 +/- 51 mg/veh-km), NO(x) (RWC = 800 +/- 100 mg/kg; traffic = 4400 +/- 100 mg/veh-km), BC (RWC = 74 +/- 6 mg/kg; traffic = 60 +/- 3 mg/veh-km) and particle number (N) with size distribution between 25 and 600 nm (N(25-600)) (RWC = 8.9 +/- 1 x 10(14) pt/kg; traffic = 6.7 +/- 0.5 x 10(14) pt/veh-km). The obtained emission factors are comparable to results reported in the literature. The size distribution of the N emission factors for traffic was shown to be different than for RWC. The main difference is that although traffic emissions show a bimodal size distribution with a main mode below 30 nm and a secondary one around 100 nm, RWC emissions show the main mode slightly below 100 nm and a smaller nucleation mode below 50 nm.

  7. Potential of forest management to reduce French carbon emissions - regional modelling of the French forest carbon balance from the forest to the wood.

    Science.gov (United States)

    Valade, A.; Luyssaert, S.; Bellassen, V.; Vallet, P.

    2015-12-01

    In France the low levels of forest harvest (40 Mm3 per year over a volume increment of 89Mm3) is frequently cited to push for a more intensive management of the forest that would help reducing CO2 emissions. This reasoning overlooks the medium-to-long-term effects on the carbon uptake at the national scale that result from changes in the forest's structure and delayed emissions from products decay and bioenergy burning, both determinant for the overall C fluxes between the biosphere and the atmosphere. To address the impacts of an increase in harvest removal on biosphere-atmosphere carbon fluxes at national scale, we build a consistent regional modeling framework to integrate the forest-carbon system from photosynthesis to wood uses. We aim at bridging the gap between regional ecosystem modeling and land managers' considerations, to assess the synergistic and antagonistic effects of management strategies over C-based forest services: C-sequestration, energy and material provision, fossil fuel substitution. For this, we built on inventory data to develop a spatial forest growth simulator and design a novel method for diagnosing the current level of management based on stand characteristics (density, quadratic mean diameter or exploitability). The growth and harvest simulated are then processed with a life cycle analysis to account for wood transformation and uses. Three scenarii describe increases in biomass removals either driven by energy production target (set based on national prospective with a lock on minimum harvest diameters) or by changes in management practices (shorter or longer rotations, management of currently unmanaged forests) to be compared with business as usual simulations. Our management levels' diagnostics quantifies undermanagement at national scale and evidences the large weight of ownership-based undermanagement with an average of 26% of the national forest (between 10% and 40% per species) and thus represents a huge potential wood resource

  8. Territorial Balancing of Poles of Development

    Directory of Open Access Journals (Sweden)

    CLAUDIA POPESCU

    2008-01-01

    Full Text Available The paper is part of the study "Specific problems of the development of the settlement network in south-eastern Romania. Regions of development 3 (South, 4 (South-West and 8 (Bucharest-Ilfov" elaborated during 2004 – 2006, within the AMTRANS programme funded by the Ministry of Education and Research, coordinated by INCD – URBANPROIECT in partnership with the Institute of Geography of the Romanian Academy and the Qualification in Statistics National Centre. The general objective of the project was sustainable and balanced spatial development of the settlement network and promotion of new relationships between urban and rural. Concretely, the study has produced a model of a polycentric and balanced settlement network according to the European principles. The case study testing and validating this model took place in southern Romania, territory exhibiting acutely the entire range of problems related to the state of the settlement network: profoundly large rural areas, accentuated dynamics of declaring new cities without sufficient evidence, excessive polarization exercised by Bucharest, etc. The paper presents the intervention directions needed to balance in the territory urban poles within the studied area, focusing on the establishment of orientation policies to consolidate the role of each settlement based on the hierarchical level of importance: European, national, regional, and local. The paper also identifies possible functional urban areas: the metropolitan area of Bucharest, areas of potential strategic integration, areas of cooperation between the small and medium-sized cities and the rural regions. Within each of these areas, the paper proposes to establish new relationships between urban and rural based on partnership, involving cooperation and coordination in achieving common goals.The study considers that the poles of development are the key element of proposed model, and their identification, formation, and balanced distribution

  9. Electrical Transfer Function and Poling Mechanisms for Nonlinear Optical Polymer Modulators

    Science.gov (United States)

    Watson, Michael Dale

    2004-01-01

    Electro-Optic Polymers hold great promise in increased electro-optic coefficients as compared to their inorganic corollaries. Many researchers have focused on quantum chemistry to describe how the dipoles respond to temperature and electric fields. Much work has also been done for single layer films to confirm these results. For optical applications, waveguide structures are utilized to guide the optical waves in 3 layer stacks. Electrode poling is the only practical poling method for these structures. This research takes an electrical engineering approach to develop poling models and electrical and optical transfer functions of the waveguide structure. The key aspect of the poling model is the large boundary charge density deposited during the poling process. The boundary charge density also has a large effect on the electrical transfer function which is used to explain the transient response of the system. These models are experimentally verified. Exploratory experiment design is used to study poling parameters including time, temperature, and voltage. These studies verify the poling conditions for CLDX/APC and CLDZ/APEC guest host electro optic polymer films in waveguide stacks predicted by the theoretical developments.

  10. Endistel ajateenijatel pole karistust karta / Holger Roonemaa

    Index Scriptorium Estoniae

    Roonemaa, Holger

    2007-01-01

    Kevadtormi õppusel kaitseväe korda rikkunud Kuperjanovi pataljoni endistel ajateenijatel pole karistust karta, sest karistust saab määrata vaid teenistusaja jooksul. Lisa: Kuperjanovis oli vähe korda

  11. NATO poliitik : Eestil pole venelastega probleeme

    Index Scriptorium Estoniae

    2003-01-01

    NATO Parlamentaarse Assamblee poliitik Niki Bettendorf, kes kontrollis Eestis Venemaa etteheiteid, nagu rikutaks Eestis ja Lätis vene vähemuse õigusi, kinnitas, et Eestis pole suuri probleeme vene vähemusega

  12. Relation Between the Pole Mass and MS Mass of Top Quark in Supersymmetric QCD

    Institute of Scientific and Technical Information of China (English)

    CHEN Shao-Long; FENG Tai-Fu; LI Xue-Qian

    2001-01-01

    We discuss the relation between the pole mass and MS mass of top quark in the framework of the supersymmetric QCD. We find that the supersymmetric contributions are comparable to those of the standard model.

  13. Relation Between the Pole Mass and MS Mass of Top Quark in Supersymmetric QCD

    Institute of Scientific and Technical Information of China (English)

    CHENShao-Long; FENGTai-Fu; 等

    2001-01-01

    We discuss the relation between the pole mass and MS mass of top quark in the framework of the supersymmetric QCD.We find that the supersymmetric contributions are comparable to those of the standard model.

  14. Upper mesosphere dynamical behavior near South Pole

    OpenAIRE

    Hernandez, Gonzalo; Smith,Roger W.

    1997-01-01

    Recent ground-based measurements of the neutral winds and temperatures at mesospheric heights near the Earth's rotational pole, at Amundsen-Scott Station, show that the neutral atmosphere has a restricted zonal wavenumber behavior at very-high latitudes. This can be interpreted as the natural response of the atmosphere to the boundary conditions at the rotational pole (s). Experimentally, mostly planetary-scale waves have been observed during the austral winter.

  15. Glacier melt on the Third Pole

    Science.gov (United States)

    Yao, T.

    2015-12-01

    With an average elevation above 4,000 metres, the Third Pole (TP) is a unique region with many high mountains centered on the Tibetan Plateau stretching over 5 million square kilometers. Major environmental changes are taking place on the TP characterized by complex interactions of atmospheric, cryospheric, hydrological, geological and environmental processes. These processes are critical for the well-being of the three billion people inhabiting the plateau and the surrounding regions. Glacier melt is one of the most significant environmental changes observed on the TP. Over the past decade, most of the glaciers on the TP have undergone considerable melt. The Third Pole Environment (TPE) has focused on the causes of the glacier melt by conducting large-scale ground in-situ observation and monitoring, analyzing satellite images and remote sensing data, and applying numerical modeling to environmental research on the TP. The studies of long-term record of water stable isotopes in precipitation and ice core throughout the TP have revealed different features with regions, thus proposing significant influence of atmospheric circulations on spatial precipitation pattern over the TP. Validation of the result by isotope-equipped general circulation models confirms the spatial distribution of different atmospheric circulation dominances on the TP, with northern part dominated by the westerlies, southern part by the summer monsoon, and central part featuring the influences of both circulation systems. Such unique circulation patterns also bear directly on the status of glaciers and lakes over the TP and its surroundings. The studies therefore found the largest glacier melt in the monsoon-dominated southern part, moderate melt in the central part of transition, and the least melt, or even slight advance in the westerlies-dominated northern TP. It is clear that some mountains on the TP are undergoing rapid melt and the consequence of without ice and snow will be very soon. The

  16. 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

  17. Neuromorphic Continuous-Time State Space Pole Placement Adaptive Control

    Institute of Scientific and Technical Information of China (English)

    卢钊; 孙明伟

    2003-01-01

    A neuromorphic continuous-time state space pole assignment adaptive controller is proposed, which is particularly appropriate for controlling a large-scale time-variant state-space model due to the parallely distributed nature of neurocomputing. In our approach, Hopfield neural network is exploited to identify the parameters of a continuous-time state-space model, and a dedicated recurrent neural network is designed to compute pole placement feedback control law in real time. Thus the identification and the control computation are incorporated in the closed-loop, adaptive, real-time control system. The merit of this approach is that the neural networks converge to their solutions very quickly and simultaneously.

  18. Diphotons at the $Z$-pole in Models of the 750 GeV Resonance Decaying to Axion-Like Particles

    CERN Document Server

    Alves, Alexandre; Sinha, Kuver

    2016-01-01

    Models in which the 750 GeV resonance ($S$) decays to two light axion-like particles (ALPs $a$), which in turn decay to collimated photons mimicking the observed signal, are motivated by Hidden Valley scenarios and could also provide a mechanism by which a $S \\to \\gamma \\gamma$ signal persists while $S \\to Z \\gamma,\\; ZZ$ and $WW$ remain subdued in the near future. We point out that these Hidden Valley like models invoking $S \\to aa \\to 4 \\gamma$ must also contend with $Z \\to a (\\to \\gamma \\gamma) \\gamma$ constraints coming from CDF and ATLAS. Within an effective field theory framework, we work out the constraints on the couplings of $S$ to $a$ and gauge bosons coming from photonic $Z$ decays and ensuring that the ALPs decay inside the electromagnetic calorimeter, in two regimes - where $a$ decays primarily to photons, and where $a$ also has hadronic branchings. The analysis is done for both when $S$ has a large as well as a narrow width, and for different relative contributions to the signal coming from $S \\...

  19. Poles apart: Scott, Amundsen and science.

    Science.gov (United States)

    Larson, Edward J

    2011-12-01

    One hundred years ago, teams led by Roald Amundsen and Robert Scott may have been heading in the same direction but they were poles apart in the way they sought their goals. Amundsen led a five-person team of expert Nordic skiers and dog-sledders with a single goal: getting to the South Pole first. He planned and executed the effort brilliantly. Scott, in contrast, led a complex and multi-faceted Antarctic expedition with 33 explorers and scientists, many of whom were focused on ambitious and often taxing scientific research projects that had nothing whatsoever to do with reaching the Pole. Although Scott failed to reach the South Pole first and died with four men on the return trip, his expedition made significant contributions to Antarctic science. Indeed, at least some of Scott's failure to reach the Pole first and the subsequent death of his polar party on the return trip can be attributed to burden of trying to do too much and not focusing on reaching the pole.

  20. Pole movement in electronic and optoelectronic oscillators

    Science.gov (United States)

    Chatterjee, S.; Pal, S.; Biswas, B. N.

    2013-12-01

    An RLC circuit with poles on the left half of the complex frequency plane is capable of executing transient oscillations. During this period, energy conversion from potential to kinetic and from kinetic to potential continuously goes on, until the stored energy is lost in dissipation through the resistance. On the other hand, in an electronic or opto-electronic oscillator with an embedded RLC circuit, the poles are forcibly placed on the right-half plane (RHP) and as far as practicable away from the imaginary axis in order to help the growth of oscillation as quickly as possible. And ultimately, it is imagined that, like the case of an ideal linear harmonic oscillator, the poles are frozen on the imaginary axis so that the oscillation neither grows nor decays. The authors feel that this act of holding the poles right on the imaginary axis is a theoretical conjecture in a soft or hard self-excited oscillator. In this article, a detailed discussion on pole movement in an electronic and opto-electronic oscillator is carried out from the basic concept. A new analytical method for estimating the time-dependent part of the pole is introduced here.

  1. Modelling winter organic aerosol at the European scale with CAMx: evaluation and source apportionment with a VBS parameterization based on novel wood burning smog chamber experiments

    Directory of Open Access Journals (Sweden)

    G. Ciarelli

    2017-06-01

    Full Text Available We evaluated a modified VBS (volatility basis set scheme to treat biomass-burning-like organic aerosol (BBOA implemented in CAMx (Comprehensive Air Quality Model with extensions. The updated scheme was parameterized with novel wood combustion smog chamber experiments using a hybrid VBS framework which accounts for a mixture of wood burning organic aerosol precursors and their further functionalization and fragmentation in the atmosphere. The new scheme was evaluated for one of the winter EMEP intensive campaigns (February–March 2009 against aerosol mass spectrometer (AMS measurements performed at 11 sites in Europe. We found a considerable improvement for the modelled organic aerosol (OA mass compared to our previous model application with the mean fractional bias (MFB reduced from −61 to −29 %. We performed model-based source apportionment studies and compared results against positive matrix factorization (PMF analysis performed on OA AMS data. Both model and observations suggest that OA was mainly of secondary origin at almost all sites. Modelled secondary organic aerosol (SOA contributions to total OA varied from 32 to 88 % (with an average contribution of 62 % and absolute concentrations were generally under-predicted. Modelled primary hydrocarbon-like organic aerosol (HOA and primary biomass-burning-like aerosol (BBPOA fractions contributed to a lesser extent (HOA from 3 to 30 %, and BBPOA from 1 to 39 % with average contributions of 13 and 25 %, respectively. Modelled BBPOA fractions were found to represent 12 to 64 % of the total residential-heating-related OA, with increasing contributions at stations located in the northern part of the domain. Source apportionment studies were performed to assess the contribution of residential and non-residential combustion precursors to the total SOA. Non-residential combustion and road transportation sector contributed about 30–40 % to SOA formation (with increasing

  2. Welding of solid wood

    OpenAIRE

    Ivica Župčić; Goran Mihulja; Andrija Bogner; Ivica Grbac; Ivica @up~i}, Goran Mihulja, Andrija Bogner, Ivica Grbac,; Božidar Hrovat

    2008-01-01

    This paper presents the up-to-date knowledge and results of the application of wood welding techniques at the Faculty of Forestry University of Zagreb. Wood welding technologies have been developed as a new way of bonding timber by using high temperature generatedby friction and pressure. Timber is assembled without any adhesives. During the process the surface layer of timber (lignin), which is in direct contact with its counterpart, melts due to high pressure and temperature, which is usual...

  3. Clouds Over the North Pole

    Science.gov (United States)

    2004-01-01

    [figure removed for brevity, see original site] Released 29 June 2004 The atmosphere of Mars is a dynamic system. Water-ice clouds, fog, and hazes can make imaging the surface from space difficult. Dust storms can grow from local disturbances to global sizes, through which imaging is impossible. Seasonal temperature changes are the usual drivers in cloud and dust storm development and growth. Eons of atmospheric dust storm activity has left its mark on the surface of Mars. Dust carried aloft by the wind has settled out on every available surface; sand dunes have been created and moved by centuries of wind; and the effect of continual sand-blasting has modified many regions of Mars, creating yardangs and other unusual surface forms. Like yesterday's image, the linear 'ripples' are water-ice clouds. As spring is deepening at the North Pole these clouds are becoming more prevalent. Image information: VIS instrument. Latitude 68.9, Longitude 135.5 East (224.5 West). 38 meter/pixel resolution. Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time. NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are

  4. Steam gasification of wood biomass in a fluidized biocatalytic system bed gasifier: A model development and validation using experiment and Boubaker Polynomials Expansion Scheme BPES

    Directory of Open Access Journals (Sweden)

    Luigi Vecchione

    2015-07-01

    Full Text Available One of the most important issues in biomass biocatalytic gasification is the correct prediction of gasification products, with particular attention to the Topping Atmosphere Residues (TARs. In this work, performedwithin the European 7FP UNIfHY project, we develops and validate experimentally a model which is able of predicting the outputs,including TARs, of a steam-fluidized bed biomass gasifier. Pine wood was chosen as biomass feedstock: the products obtained in pyrolysis tests are the relevant model input. Hydrodynamics and chemical properties of the reacting system are considered: the hydrodynamic approach is based on the two phase theory of fluidization, meanwhile the chemical model is based on the kinetic equations for the heterogeneous and homogenous reactions. The derived differentials equations for the gasifier at steady state were implemented MATLAB. Solution was consecutively carried out using the Boubaker Polynomials Expansion Scheme by varying steam/biomass ratio (0.5-1 and operating temperature (750-850°C.The comparison between models and experimental results showed that the model is able of predicting gas mole fractions and production rate including most of the representative TARs compounds

  5. DecAID advisor: a tool for managing snags, down wood and wood decay in PNW forests.

    Science.gov (United States)

    Bruce G. Marcot; Grant Gunderson; Kim Mellen; Janet L. Ohmann

    2004-01-01

    Past tools for modeling and setting guidelines for snag and down wood management have been based on theory, professional judgment, models of wildlife species use as habitat and empirical data. However, recent studies reveal that guidelines for amounts of snags and down wood on national forests of Washington and Oregon may have been lower than the new field data on use...

  6. Predictive Modeling of Black Spruce (Picea mariana (Mill. B.S.P. Wood Density Using Stand Structure Variables Derived from Airborne LiDAR Data in Boreal Forests of Ontario

    Directory of Open Access Journals (Sweden)

    Bharat Pokharel

    2016-12-01

    Full Text Available Our objective was to model the average wood density in black spruce trees in representative stands across a boreal forest landscape based on relationships with predictor variables extracted from airborne light detection and ranging (LiDAR point cloud data. Increment core samples were collected from dominant or co-dominant black spruce trees in a network of 400 m2 plots distributed among forest stands representing the full range of species composition and stand development across a 1,231,707 ha forest management unit in northeastern Ontario, Canada. Wood quality data were generated from optical microscopy, image analysis, X-ray densitometry and diffractometry as employed in SilviScan™. Each increment core was associated with a set of field measurements at the plot level as well as a suite of LiDAR-derived variables calculated on a 20 × 20 m raster from a wall-to-wall coverage at a resolution of ~1 point m−2. We used a multiple linear regression approach to identify important predictor variables and describe relationships between stand structure and wood density for average black spruce trees in the stands we observed. A hierarchical classification model was then fitted using random forests to make spatial predictions of mean wood density for average trees in black spruce stands. The model explained 39 percent of the variance in the response variable, with an estimated root mean square error of 38.8 (kg·m−3. Among the predictor variables, P20 (second decile LiDAR height in m and quadratic mean diameter were most important. Other predictors describing canopy depth and cover were of secondary importance and differed according to the modeling approach. LiDAR-derived variables appear to capture differences in stand structure that reflect different constraints on growth rates, determining the proportion of thin-walled earlywood cells in black spruce stems, and ultimately influencing the pattern of variation in important wood quality attributes

  7. Wind Stress Forcing of the North Sea "Pole Tide"

    Science.gov (United States)

    OConnor, William P.; Chao, Benjamin Fong; Zheng, Dawei; Au, Andrew Y.

    1998-01-01

    We conducted numerical simulations of the wind-forcing of the sea level variations in the North Sea using a barotropic ocean model with realistic geography, bathymetry, and boundary conditions, to examine the forcing of the 14-month "pole tide" which is known to be strong along the Denmark- Netherlands coast. The simulation input is the monthly-mean surface wind stress field from the National Centers for Environmental Prediction (NCEP) reanalysis for the 40-year period 1958-1997. The output sea level response was then compared with 10 coastal tide gauge records from the Permanent Service for Mean Sea Level (PSMSL). Besides the strong seasonal variations, several prominent quasi-periodicities exist at around 7 years, 3 years, 14 months, 9 months, and 6.5 months. Correlation and spectral analyses show remarkable agreement between the model output and the observations, particularly in the 14-month, or Chandler period band. The latter indicates that the enhanced pole tide found in the North Sea along the Denmark-Netherlands coast is actually the coastal setup response to wind stress forcing with a periodicity of 14 months. We find no need to invoke a geophysical explanation involving resonance-enhancement of pole tide in the North Sea to explain the observations.

  8. Jupiter's interior and deep atmosphere: The initial pole-to-pole passes with the Juno spacecraft

    DEFF Research Database (Denmark)

    Bolton, S. J.; Adriani, Alberto; Adumitroaie, V.

    2017-01-01

    On 27 August 2016, the Juno spacecraft acquired science observations of Jupiter, passing less than 5000 kilometers above the equatorial cloud tops. Images of Jupiter's poles show a chaotic scene, unlike Saturn's poles. Microwave sounding reveals weather features at pressures deeper than 100 bars,...

  9. On the pole content of coupled channels chiral approaches used for the K bar N system

    Science.gov (United States)

    Cieplý, A.; Mai, M.; Meißner, Ulf-G.; Smejkal, J.

    2016-10-01

    Several theoretical groups describe the antikaon-nucleon interaction at low energies within approaches based on the chiral SU(3) dynamics and including next-to-leading order contributions. We present a comparative analysis of the pertinent models and discuss in detail their pole contents. It is demonstrated that the approaches lead to very different predictions for the K- p amplitude extrapolated to subthreshold energies as well as for the K- n amplitude. The origin of the poles generated by the models is traced to the so-called zero coupling limit, in which the inter-channel couplings are switched off. This provides new insights into the pole contents of the various approaches. In particular, different concepts of forming the Λ (1405) resonance are revealed and constraints related to the appearance of such poles in a given approach are discussed.

  10. Reorientation of the early lunar pole

    Science.gov (United States)

    Takahashi, Futoshi; Tsunakawa, Hideo; Shimizu, Hisayoshi; Shibuya, Hidetoshi; Matsushima, Masaki

    2014-06-01

    Palaeomagnetic measurements suggest that an active core dynamo operated on the Moon from 4.2 to 3.56 billion years ago. Since the Apollo era, many magnetic anomalies have been observed on the Moon. The magnetization of the lunar crust in some of these regions could preserve the signature of an early dipolar magnetic field generated by a core dynamo. Thus, the magnetic anomalies may yield information about the position of the palaeomagnetic pole during the time that the dynamo operated. Here we present a comprehensive survey of magnetic anomalies on the lunar surface using magnetometer data obtained by the Lunar Prospector and Kaguya lunar orbiters. We extract magnetization vectors from 24 magnetic anomalies using an iterative inversion method and derive the palaeomagnetic poles. We find that the north poles, as well as the antipodal south poles, cluster in two distinct locations: one near the present rotation axis and the other at mid-latitude. The clustering is consistent with a dipole-dominated magnetic field generated in the lunar core by a dynamo that was reversing, much like that of Earth. Furthermore, the two pole clusters imply that the Moon experienced a polar wander event during its ancient history due to the reorientation of the Moon with respect to its spin axis by 45°-60°.

  11. Industry in growth poles of Romania

    Directory of Open Access Journals (Sweden)

    Cristina Iacoboaea

    2015-03-01

    Full Text Available A competitive industry can reduce costs and prices, can create new products, thus contributing significantly to productivity growth throughout the economy. The industry is also the main source of innovation necessary for society to meet the challenges faced. Growth poles have the ability to spread economic development in adjacent areas and contributes significantly to the territorial development of the country. This article aims to analyze the current state of industry growth poles of Romania, in terms of number of employees, distribution of sub-industries and density of firms in industry. It also highlights business structures and industry clusters located in the growth poles, as solutions for boosting economic growth and creation of added value. Analysis performed leads to the conclusion that all growth poles are engines of economical development in the industry for the regios of origin. We distinguish growth poles Timişoara and Cluj-Napoca whose economic advantage is given by the favorable position close to the markets of the European Union.

  12. Poles, the only true resonant-state signals, are extracted from a worldwide collection of partial wave amplitudes using only one, well controlled pole-extraction method

    CERN Document Server

    Hadžimehmedović, M; Švarc, A; Osmanović, H; Stahov, J

    2011-01-01

    Each and every energy dependent partial-wave analysis is parameterizing the pole positions in a procedure defined by the way how the continuous energy dependence is implemented. These pole positions are, henceforth, inherently model dependent. To reduce this model dependence, we use only one, coupled-channel, unitary, fully analytic method based on the isobar approximation to extract the pole positions from the each available member of the worldwide collection of partial wave amplitudes which are understood as nothing more but a good energy dependent representation of genuine experimental numbers assembled in a form of partial-wave data. In that way, the model dependence related to the different assumptions on the analytic form of the partial-wave amplitudes is avoided, and the true confidence limit for the existence of a particular resonant state, at least in one model, is established. The way how the method works, and first results are demonstrated for the S11 partial wave.

  13. Integrated 3D printing and corona poling process of PVDF piezoelectric films for pressure sensor application

    Science.gov (United States)

    Kim, Hoejin; Torres, Fernando; Wu, Yanyu; Villagran, Dino; Lin, Yirong; Tseng, Tzu-Liang(Bill

    2017-08-01

    This paper presents a novel process to fabricate piezoelectric films from polyvinylidene fluoride (PVDF) polymer using integrated fused deposition modeling (FDM) 3D printing and corona poling technique. Corona poling is one of many effective poling processes that has received attention to activate PVDF as a piezoelectric responsive material. The corona poling process occurs when a PVDF polymer is exposed to a high electric field created and controlled through an electrically charged needle and a grid electrode under heating environment. FDM 3D printing has seen extensive progress in fabricating thermoplastic materials and structures, including PVDF. However, post processing techniques such as poling is needed to align the dipoles in order to gain piezoelectric properties. To further simplify the piezoelectric sensors and structures fabrication process, this paper proposes an integrated 3D printing process with corona poling to fabricate piezoelectric PVDF sensors without post poling process. This proposed process, named ‘Integrated 3D Printing and Corona poling process’ (IPC), uses the 3D printer’s nozzle and heating bed as anode and cathode, respectively, to create poling electric fields in a controlled heating environment. The nozzle travels along the programmed path with fixed distance between nozzle tip and sample’s top surface. Simultaneously, the electric field between the nozzle and bottom heating pad promotes the alignment of dipole moment of PVDF molecular chains. The crystalline phase transformation and output current generated by printed samples under different electric fields in this process were characterized by a Fourier transform infrared spectroscopy and through fatigue load frame. It is demonstrated that piezoelectric PVDF films with enhanced β-phase percentage can be fabricated using the IPC process. In addition, mechanical properties of printed PVDF was investigated by tensile testing. It is expected to expand the use of additive

  14. Photodegradation of thermally modified wood.

    Science.gov (United States)

    Srinivas, Kavyashree; Pandey, Krishna K

    2012-12-01

    Natural wood, being biological material, undergoes rapid degradation by ultraviolet (UV) radiations and other environmental factors under outdoor exposure. In order to protect wood from such degradation, the chemical structure of wood is altered by chemical modification or heat treatment. In the present study, heat treated specimens of rubberwood (Hevea brasiliensis) were exposed to xenon light source in a weather-o-meter for different periods up to 300 h. Photostability of modified and unmodified wood was evaluated in terms of colour and chemical changes. Light coloured untreated wood became dark upon UV irradiation whereas, dark colour of heat treated wood lightened on UV exposure. CIE lightness parameter (L(*)) decreased for untreated wood whereas its value increased for heat treated wood upon irradiation. Other colour coordinates a(*) and b(*) increased with exposure duration for both untreated and heat treated wood. The overall colour change (ΔE(*)) increased for both untreated and heat treated wood. The Fourier Transform Infrared (FTIR) spectroscopic studies revealed severe lignin degradation of heat treated wood due to UV light exposure. Colour changes and FTIR measurements indicate that thermal modification of wood was ineffective in restricting light induced colour changes and photodegradation of wood polymers.

  15. A method to determine asteroid poles

    Science.gov (United States)

    Deangelis, G.

    1993-01-01

    The determination of spin axis and shape is well known to be of fundamental importance for studies about the rotational and physical properties of asteroids. In particular, knowledge that the pole coordinate distribution is random or not could indicate the probable non-Maxwellian distribution of asteroid spin axes, while the distribution in terms of size and shape could place important constraints on the theories about the collisional history of some individual asteroids, of asteroid families, and of the asteroid population as a whole. Many kinds of methods have been developed to determine pole coordinates. An EA method is presented, from which it is possible to obtain the solution with no trial poles, but with a simultaneous least square fit on both the E and A part. Results for rotational and shape parameters were obtained for 18 asteroids: the values of the obtained parameters are generally in close agreement with those of others.

  16. 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.

  17. Fatigue Damage in Wood

    DEFF Research Database (Denmark)

    Clorius, Christian Odin; Pedersen, Martin Bo Uhre; Hoffmeyer, Preben;

    1996-01-01

    An investigation of fatigue failure in wood subjected to load cycles in compression parallel to grain is presented. Fatigue failure is found to depend both on the total time under load and on the number of cycles.Recent accelerated fatigue research on wood is reviewed, and a discrepancy between...... failure explanation under fatigue and static load conditions is observed. In the present study small clear specimens of spruce are taken to failure in square wave formed fatigue loading at a stress excitation level corresponding to 80% of the short term strength. Four frequencies ranging from 0.01 Hz...... to 10 Hz are used. The number of cycles to failure is found to be a poor measure of the fatigue performance of wood. Creep, maximum strain, stiffness and work are monitored throughout the fatigue tests. Accumulated creep is suggested identified with damage and a correlation between stiffness reduction...

  18. Wood for sound.

    Science.gov (United States)

    Wegst, Ulrike G K

    2006-10-01

    The unique mechanical and acoustical properties of wood and its aesthetic appeal still make it the material of choice for musical instruments and the interior of concert halls. Worldwide, several hundred wood species are available for making wind, string, or percussion instruments. Over generations, first by trial and error and more recently by scientific approach, the most appropriate species were found for each instrument and application. Using material property charts on which acoustic properties such as the speed of sound, the characteristic impedance, the sound radiation coefficient, and the loss coefficient are plotted against one another for woods. We analyze and explain why spruce is the preferred choice for soundboards, why tropical species are favored for xylophone bars and woodwind instruments, why violinists still prefer pernambuco over other species as a bow material, and why hornbeam and birch are used in piano actions.

  19. Rules of the road: A qualitative and quantitative synthesis of large wood transport through drainage networks

    Science.gov (United States)

    Kramer, Natalie; Wohl, Ellen

    2017-02-01

    To effectively manage wood in rivers, we need a better understanding of wood mobility within river networks. Here, we review primarily field-based (and some numerical) studies of wood transport. We distinguish small, medium, large, and great rivers based on wood piece dimensions relative to channel and flow dimensions and dominant controls on wood transport. We suggest further identification and designation of wood transport regimes as a useful way to characterize spatial-temporal network heterogeneity and to conceptualize the primary controls on wood mobility in diverse river segments. We draw analogies between wood and bedload transport, including distinguishing Eulerian and Lagrangian approaches, exploring transport capacity, and quantifying thresholds of wood mobility. We identify mobility envelopes for remobilization of wood with relation to increasing peak discharges, stream size, and dimensionless log lengths. Wood transport in natural channels exhibits high spatial and temporal variability, with discontinuities along the channel network at bankfull flow and when log lengths equal channel widths. Although median mobilization rates increase with increasing channel size, maximum mobilization rates are greatest in medium-sized channels. Most wood is transported during relatively infrequent high flows, but flows under bankfull can transport up to 30% of stored wood. We use conceptual models of dynamic equilibrium of wood in storage and of spiralling wood transport paths through drainage networks, as well as a metaphor of traffic on a road, to explore discontinuous wood movement through a river network. The primary limitations to describing wood transport are inappropriate time scales of observation and lack of sufficient data on mobility from diverse rivers. Improving models of wood flux requires better characterization of average step lengths within the lifetime travel path of a piece of wood. We suggest that future studies focus on: (i) continuous or high

  20. Variation in root wood anatomy

    NARCIS (Netherlands)

    Cutler, D.F.

    1976-01-01

    Variability in the anatomy of root wood of selected specimens particularly Fraxinus excelsior L. and Acer pseudoplatanus L. in the Kew reference microscope slide collection is discussed in relation to generalised statements in the literature on root wood anatomy.

  1. Variation in root wood anatomy

    NARCIS (Netherlands)

    Cutler, D.F.

    1976-01-01

    Variability in the anatomy of root wood of selected specimens particularly Fraxinus excelsior L. and Acer pseudoplatanus L. in the Kew reference microscope slide collection is discussed in relation to generalised statements in the literature on root wood anatomy.

  2. The 10 Meter South Pole Telescope

    OpenAIRE

    Carlstrom, J. E.; Ade, P. A. R.; Aird, K. A.; Benson, B. A.; Bleem, L. E.; Busetti, S.; Chang, C. L.; Chauvin, E; Cho, H. -M.; Crawford, T. M.; Crites, A. T.; Dobbs, M. A.; Halverson, N. W.; Heimsath, S.; Holzapfel, W. L.

    2009-01-01

    The South Pole Telescope (SPT) is a 10 m diameter, wide-field, offset Gregorian telescope with a 966-pixel, multi-color, millimeter-wave, bolometer camera. It is located at the Amundsen-Scott South Pole station in Antarctica. The design of the SPT emphasizes careful control of spillover and scattering, to minimize noise and false signals due to ground pickup. The key initial project is a large-area survey at wavelengths of 3, 2 and 1.3 mm, to detect clusters of galaxies via the Sunyaev-Zeldov...

  3. Log amplifier with pole-zero compensation

    Science.gov (United States)

    Brookshier, William

    1987-01-01

    A logarithmic amplifier circuit provides pole-zero compensation for improved stability and response time over 6-8 decades of input signal frequency. The amplifier circuit includes a first operational amplifier with a first feedback loop which includes a second, inverting operational amplifier in a second feedback loop. The compensated output signal is provided by the second operational amplifier with the log elements, i.e., resistors, and the compensating capacitors in each of the feedback loops having equal values so that each break point or pole is offset by a compensating break point or zero.

  4. Pole solutions for flame front propagation

    CERN Document Server

    Kupervasser, Oleg

    2015-01-01

    This book deals with solving mathematically the unsteady flame propagation equations. New original mathematical methods for solving complex non-linear equations and investigating their properties are presented. Pole solutions for flame front propagation are developed. Premixed flames and filtration combustion have remarkable properties: the complex nonlinear integro-differential equations for these problems have exact analytical solutions described by the motion of poles in a complex plane. Instead of complex equations, a finite set of ordinary differential equations is applied. These solutions help to investigate analytically and numerically properties of the flame front propagation equations.

  5. POLES OF ZETA FUNCTIONS OF COMPLETE INTERSECTIONS

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A vanishing theorem is proved for -adic cohomology with compact support on an affine (singular) complete intersection. As an application, it is shown that for an affine complete intersection defined over a finite field of q elements, the reciprocal "poles" of the zeta function are always divisible by q as algebraic integers. A p-adic proof is also given, which leads to further q-divisibility of the poles or equivalently an improvement of the polar part of the AxKatz theorem for an affine complete intersection. Similar results hold for a projective complete intersection.

  6. TCP HolyWood

    OpenAIRE

    Oscar Núñez Mori

    2005-01-01

    We introduce a new end-to-end, sender side Transport Control Protocol called TCP HolyWood or in short TCP-HW. In a simulated wired environment, TCP HolyWood outperforms in average throughput, three of the more important TCP protocols ever made, we are talking about TCP Reno, TCP Westwood, and TCP Vegas; and in average jitter to TCP Reno and TCP Vegas too. In addition, according to Jain’s index, our proposal is as fair as TCP Reno, the Standard. Apresentamos um novo Protocolo de Controle de...

  7. False "highlighting" with Wood's lamp.

    Science.gov (United States)

    Silverberg, Jonathan I; Silverberg, Nanette B

    2014-01-01

    Wood's lamp evaluation is used to diagnose pigmentary disorders. For example, vitiligo typically demonstrates lesional enhancement under Wood's lamp evaluation. Numerous false positive enhancing lesions can be noted in the skin. We describe a 5-year-old Hispanic boy who had painted his face with highlighter, producing enhancing lesions under Wood's lamp. Physicians who use Wood's lamp should be aware that the appearance of markers and highlighter can mimic that of true clinical illnesses.

  8. Uncertainty maps for asteroid shape and pole solutions

    Science.gov (United States)

    Bartczak, Przemyslaw; Dudzinski, Grzegorz

    2016-10-01

    SAGE (Shaping Asteroids with Genetic Evolution) inversion method is based on genetic algorithm to obtain pole solutions, rotation periods and non-convex shapes of asteroids (Bartczak et.al, 2014). During the process computer graphics methods are used to compare model's synthetic lightcurves to photometric observations. The method is suitable for modelling both single and binary objects. A modelling run starts with a sphere, with no assumptions about the shape, and subsequently it converges to a stable spin and shape solution. Center of mas and moment of inertia are calculated for each model.Modelling of an asteroid consists of multiple runs of the process, each of them following different path towards a stable solution. As a result we obtain a family of solutions. If enough data is provided, solutions are consistent with each other and can be used for error estimation.We choose only the best models from a family of solutions, meaning every model that fits 5% threshold above best χ2 found. By comparing them we are able to construct a map of uncertainties for the shape, showing areas in good and poor agreement with chosen models. Such map can then be represented with a 3D visualisation. Moreover, we create a map of errors for pole solutions and periods.

  9. Comparison between different methods for inspection of wooden poles in service in electricity distribution networks; Comparacao entre diferentes metodos de inspecao de postes de madeira em servico em redes de distribuicao de energia

    Energy Technology Data Exchange (ETDEWEB)

    Cruz, M.A.O.; Pires, M.; Dedavid, B.A.; Vidor, F.L.R.; Oliveira, W.S.; Abruzzi, R.C. [Pontificia Univ. Catolica do Rio Grande do Sul (PUC-RS), Porto Alegre, RS (Brazil). Programa de Pos-Graduacao em Engenharia e Tecnologia de Materiais (PGETEMA)], Email: mpires@pucrs.br

    2010-07-01

    The pole is the main support structure of the electric network and should be inspected regularly to ensure system security. The aim of this study is to compare traditional and instrumental inspection methods of the wooden poles in service in AES Sul power distribution network (Montenegro, RS). The inspections were conducted in about 180 poles in two measurement campaigns (2001 and 2010). The procedure was based on the traditional inspection (visual inspection, percussion and effort lateral) and instrumental method based on Polux equipment that measures the penetration resistance and moisture content of wood. The results were compared in search of assertiveness of the methods used to subsidize the standardization of inspection procedures. (author)

  10. Influence of thermal treatment of wood on the aroma of a sugar cane spirit (cachaça model-solution

    Directory of Open Access Journals (Sweden)

    Marta Helena Fillet Spoto

    2011-06-01

    Full Text Available The aging process of alcoholic beverages is generally conducted in wood barrels made with species from Quercus sp. Due to the high cost and the lack of viability of commercial production of these trees in Brazil, there is demand for new alternatives to using other native species and the incorporation of new technologies that enable greater competitiveness of sugar cane spirit aged in Brazilian wood. The drying of wood, the thermal treatment applied to it, and manufacturing techniques are important tools in defining the sensory quality of alcoholic beverages after being placed in contact with the barrels. In the thermal treatment, several compounds are changed by the application of heat to the wood and various studies show the compounds are modified, different aromas are developed, there is change in color, and beverages achieve even more pleasant taste, when compared to non-treated woods. This study evaluated the existence of significant differences between hydro-alcoholic solutions of sugar cane spirits elaborated from different species of thermo-treated and non-treated wood in terms of aroma. An acceptance test was applied to evaluate the solutions preferred by tasters under specific test conditions.

  11. The trait contribution to wood decomposition rates of 15 neotropical tree species

    NARCIS (Netherlands)

    Geffen, van K.G.; Poorter, L.; Sass-Klaassen, U.; Logtestijn, R.S.P.; Cornelissen, J.H.C.

    2010-01-01

    The decomposition of dead wood is a critical uncertainty in models of the global carbon cycle. Despite this, relatively few studies have focused on dead wood decomposition, with a strong bias to higher latitudes. Especially the effect of inter-specific variation in species traits on differences wood

  12. On the design of pole modules for inverse systems

    Science.gov (United States)

    Wyman, B. F.; Sain, M. K.

    1985-01-01

    When a linear dynamical system admits more than one inverse, it is known that the pole module of any inverse must contain, either as a submodule or as a factor module, a module of fixed poles isomorphic to the zero module of the original system. Design of the pole module for such an inverse system is resolved by introducing a variable pole module for the inverse, by determining necessary and sufficient conditions for a desired module to be a variable pole module, and by studying the manner in which the fixed and variable modules assemble into the pole module of the inverse. If the fixed and variable pole spectra are disjoint, the pole module of the inverse system is a direct sum of the fixed- and variable-pole modules; if not, procedures for addressing the Jordan structure are presented.

  13. On the universality of the $J=0$ fixed pole contribution in DVCS

    CERN Document Server

    Müller, Dieter

    2016-01-01

    S. Brodsky, F.J. Llanes-Estrada, and A. Szczepaniak formulated the $J=0$ fixed pole universality hypothesis for (deeply) virtual Compton scattering. We show that in the Bjorken limit this hypothesis is equivalent to the validity of the inverse moment sum rule for the $D$-term form factor. However, any supplementary $D$-term added to a generalized parton distribution (GPD) results in an additional $J=0$ fixed pole contribution that violates universality. Unfortunately, one can not provide any reliable theoretical argument excluding the existence of such supplementary $D$-term. Moreover, the violation of $J=0$ fixed pole universality was revealed in field theoretical GPD models. Therefore, $J=0$ fixed pole universality hypothesis remains just an external assumption and probably will never be proven theoretically.

  14. On PID Controller Design by Combining Pole Placement Technique with Symmetrical Optimum Criterion

    Directory of Open Access Journals (Sweden)

    Viorel Nicolau

    2013-01-01

    Full Text Available In this paper, aspects of analytical design of PID controllers are studied, by combining pole placement technique with symmetrical optimum criterion. The proposed method is based on low-order plant model with pure integrator, and it can be used for both fast and slow processes. Starting from the desired closed-loop transfer function, which contains a second-order oscillating system and a lead-lag compensator, it is shown that the zero value depends on the real-pole value of closed-loop transfer function. In addition, there is only one pole value, which satisfies the assumptions of symmetrical optimum criterion imposed to open-loop transfer function. In these conditions, by combining the pole placement technique with symmetrical optimum criterion, the analytical expressions of the controller parameters can be simplified. For simulations, PID autopilot design for heading control problem of a conventional ship is considered.

  15. Wood dust exposure in wood industry and forestry.

    Science.gov (United States)

    Puntarić, Dinko; Kos, Ankica; Smit, Zdenko; Zecić, Zeljko; Sega, Kresimir; Beljo-Lucić, Ruzica; Horvat, Dubravko; Bosnir, Jasna

    2005-06-01

    The aim of the study was to determine occupational exposure in Croatian wood processing industry and forest workers to harmful effects of wood dust on the risk of nose, nasal cavity and lung carcinoma. Mass concentrations of respirable particles and total wood dust were measured at two wood processing plants, three woodwork shops, and one lumbering site, where 225 total wood dust samples and 221 respirable particle samples were collected. Wood dust mass concentration was determined by the gravimetric method. Mass concentrations exceeding total wood dust maximal allowed concentration (MAC, 3 mg/m3) were measured for beechwood and oakwood dust in 38% (79/206) of study samples from wood processing facilities (plants and woodwork shops). Mass concentrations of respirable particles exceeding MAC (1 mg/m3) were recorded in 24% (48/202) of samples from wood processing facilities (mean 2.38 +/- 2.08 mg/m3 in plants and 3.6 +/- 2.22 mg/m3 in woodwork shops). Thus, 13% (27/206) of work sites in wood processing facilities failed to meet health criteria according to European guidelines. Launching of measures to reduce wood dust emission to the work area is recommended.

  16. Grant Wood: "American Gothic."

    Science.gov (United States)

    Fitzgerald, Diane M.

    1988-01-01

    Presents a lesson plan which exposes students in grades 10-12 to the visual symbols and historical references contained in Grant Wood's "American Gothic." Includes background information on the artist and the painting, instructional strategies, a studio activity, and evaluation criteria. (GEA)

  17. Wood waste in Europe

    Energy Technology Data Exchange (ETDEWEB)

    Matos, O.; Ribeiro, R. [Biomass Centre for Energy - CBE, Miranda do Corvo (Portugal)

    1997-12-31

    The energy policy of the EC, as well as most of member states points to a sizeable increase of energy production based on renewable energy sources, wood, wood residues, agricultural residues, energy crops including SRF, organic sludges, solid residues, etc. Most recent goals indicate a desirable duplication of today`s percentage by 2010. The reasons for this interest, besides diversification of sources, less dependence on imported fuels, use of endogenous resources, expected decrease of fossil fuel reserves, use of available land, additional employment and income for rural communities, etc., are related to important environmental benefits namely in terms of emissions of hot house gases. Wood waste, resulting from forest operations, cleaning, cultural and final cuttings, and from wood based industries, constitute a special important resource by reason of quality and availability. In addition to this they do not require additional land use and the removal is beneficial. In the run-up to the becoming December`s 1997 `Climate Change Summit` in Kioto, there is mounting pressure on companies to plan on carbon cuts. (author) 6 refs., 1 tab.

  18. Tannins in tropical woods

    Energy Technology Data Exchange (ETDEWEB)

    Doat, J.

    1978-01-01

    A preliminary study was made of the chemistry of pyrogallol- and catecholtannins, their general properties and methods of extraction and determination. Three methods of estimation - Lowenthal, powdered hide and spectrophotometry - were compared using two control solutions, four samples of wood and one of bark. Using the empirical powdered hide method, tannins of both types were estimated in wood and bark of various tropical species (some separately and some as a mixture), Moroccan oaks (Quercus suber and Q. ilex), and European oak 9Q. petraea). Further tests were made on the wood and bark of the two mangrove species, Rhizophora mangle and R. racemosa, by subjecting them to successive extraction with a range of solvents. None of the woods tested had as much as the 10% of tannins considered necessary in economic sources. The bark of the two mangroves, of Eucalyptus urophylla and of Prosopis africana had tannin contents over 10% and the latter two species had very favorable tannin/non-tannin ratios. All the tropical species, with the probable exception of E. urophylla, had only catecholtannins. Only the oaks and E. urophylla bark gave positive results when tested for gallotannins.

  19. Identification of coniferous woods

    Science.gov (United States)

    B. Francis Kukachka

    1960-01-01

    The identification of coniferous woods is generally regarded as being more difficult than for the hardwood species. This is due to the fact that conifers are more elemental in their structure and, as a consequence, the number of diagnostic features that may he employed is proportionately smaller. Instructions are given here in the sequential use of primary diagnostic...

  20. Wood flow problems in the Swedish forestry

    Energy Technology Data Exchange (ETDEWEB)

    Carlsson, Dick [Forestry Research Inst. of Sweden, Uppsala (Sweden); Roennqvist, M. [Linkoeping Univ. (Sweden). Dept. of Mathematics

    1998-12-31

    In this paper we give an overview of the wood-flow in Sweden including a description of organization and planning. Based on that, we will describe a number of applications or problem areas in the wood-flow chain that are currently considered by the Swedish forest companies to be important and potential in order to improve overall operations. We have focused on applications which are short term planning or operative planning. We do not give any final results as much of the development is currently ongoing or is still in a planning phase. Instead we describe what kind of models and decision support systems that could be applied in order to improve co-operation within and integration of the wood-flow chain 13 refs, 20 figs, 1 tab

  1. Numerical pole assignment by eigenvalue Jacobian inversion

    Science.gov (United States)

    Sevaston, George E.

    1986-01-01

    A numerical procedure for solving the linear pole placement problem is developed which operates by the inversion of an analytically determined eigenvalue Jacobian matrix. Attention is given to convergence characteristics and pathological situations. It is not concluded that the algorithm developed is suitable for computer-aided control system design with particular reference to the scan platform pointing control system for the Galileo spacecraft.

  2. NATO pole suutnud Gaddafit murda / Evelyn Kaldoja

    Index Scriptorium Estoniae

    Kaldoja, Evelyn, 1980-

    2011-01-01

    Liibüa diktaatori Muammar Gaddafi režiim pole langenud, Lääneriigid jätkavad sõjalisi operatsioone tsiviilelanike kaitseks. Kolm võimalikku lahendust Liibüa kriisile, BBC diplomaatiakorrespondendi Jonathan Marcuse hinnang

  3. Kosovo : kannatlikkusele lootmine pole plaan / Chris Patten

    Index Scriptorium Estoniae

    Patten, Chris

    2007-01-01

    Autor leiab, et arvestades Kosovo elanike ülekaalukat soovi olla vaba Serbiast, riigist, mis üritas nad kõrvaldada, ning alternatiivi täielikku puudumist Belgradi poolt, pole rahvusvahelisel kogukonnal muud võimalust kui anda Kosovole iseseisvus

  4. NATO pole suutnud Gaddafit murda / Evelyn Kaldoja

    Index Scriptorium Estoniae

    Kaldoja, Evelyn, 1980-

    2011-01-01

    Liibüa diktaatori Muammar Gaddafi režiim pole langenud, Lääneriigid jätkavad sõjalisi operatsioone tsiviilelanike kaitseks. Kolm võimalikku lahendust Liibüa kriisile, BBC diplomaatiakorrespondendi Jonathan Marcuse hinnang

  5. Ulysses Passes South Pole of Sun

    Institute of Scientific and Technical Information of China (English)

    程林

    1995-01-01

    On the 14th of September,1994, the fastest scientific instrument in space passed the south pole of the Sun,a place where no human-made object has been before. A spaceprobe called Ulysses made the polar pass at about midday as it continued to collect data on the solar wind,a stream of high-energy sub-atomic

  6. The South Pole Acoustic Test Setup (SPATS)

    Science.gov (United States)

    Laihem, Karim; IceCube Collaboration

    2012-11-01

    New detection techniques for (GZK) neutrinos are required for instrumenting a large detector volume needed to observe the low neutrino fluxes at the EeV energy range. Studies on a larger IceCube Neutrino Observatory at the South Pole have been intensively investigated in the last decade. A larger effective volume at a reasonable cost is possible if an acoustic array is a part of a large hybrid detector which includes radio and the existing optical array. The feasibility and the physics capabilities of an acoustic array at the South Pole depend on the knowledge of the acoustic properties of the ice such as the sound speed, the attenuation length, the background noise level and the transient rate. To investigate the ice properties, the first three acoustic strings of the South Pole Acoustic Test Setup (SPATS) have been deployed in the austral summer 2006/2007, then completed with an additional string in 2007/2008. With its four strings SPATS was able to evaluate in situ the acoustic properties of the South Pole ice in the 10-100 kHz frequency range. In this paper the performance of SPATS is described, results on the acoustic ice properties are presented and a new drilling method to deploy acoustic strings in ice is introduced.

  7. The South Pole Acoustic Test Setup (SPATS)

    Energy Technology Data Exchange (ETDEWEB)

    Laihem, Karim, E-mail: karim.laihem@physik.rwth-aachen.de [III Physikalisches Institut B, Physikzentrum, RWTH Aachen University, Otto-Blumenthal Strasse, 52074 Aachen (Germany)

    2012-11-11

    New detection techniques for (GZK) neutrinos are required for instrumenting a large detector volume needed to observe the low neutrino fluxes at the EeV energy range. Studies on a larger IceCube Neutrino Observatory at the South Pole have been intensively investigated in the last decade. A larger effective volume at a reasonable cost is possible if an acoustic array is a part of a large hybrid detector which includes radio and the existing optical array. The feasibility and the physics capabilities of an acoustic array at the South Pole depend on the knowledge of the acoustic properties of the ice such as the sound speed, the attenuation length, the background noise level and the transient rate. To investigate the ice properties, the first three acoustic strings of the South Pole Acoustic Test Setup (SPATS) have been deployed in the austral summer 2006/2007, then completed with an additional string in 2007/2008. With its four strings SPATS was able to evaluate in situ the acoustic properties of the South Pole ice in the 10-100 kHz frequency range. In this paper the performance of SPATS is described, results on the acoustic ice properties are presented and a new drilling method to deploy acoustic strings in ice is introduced.

  8. Kosovo : kannatlikkusele lootmine pole plaan / Chris Patten

    Index Scriptorium Estoniae

    Patten, Chris

    2007-01-01

    Autor leiab, et arvestades Kosovo elanike ülekaalukat soovi olla vaba Serbiast, riigist, mis üritas nad kõrvaldada, ning alternatiivi täielikku puudumist Belgradi poolt, pole rahvusvahelisel kogukonnal muud võimalust kui anda Kosovole iseseisvus

  9. Stabilization, Pole Placement, and Regular Implementability

    NARCIS (Netherlands)

    Belur, Madhu N.; Trentelman, H.L.

    2002-01-01

    In this paper, we study control by interconnection of linear differential systems. We give necessary and sufficient conditions for regular implementability of a given linear differential system. We formulate the problems of stabilization and pole placement as problems of finding a suitable, regularl

  10. Recent advances in poled optical fibres

    DEFF Research Database (Denmark)

    Pruneri, V.; Margulis, W.; Myrén, N.

    2005-01-01

    A second-order nonlinearity can be induced in optical fibres through poling. We describe accomplishments of the EU project GLAMOROUS in making low-cost high performance electrooptic and nonlinear optical fibre- and waveguide-based components. In particular a comparison with more traditional...

  11. Recent advances in poled optical fibres

    DEFF Research Database (Denmark)

    Pruneri, V.; Margulis, W.; Myrén, N.;

    2005-01-01

    A second-order nonlinearity can be induced in optical fibres through poling. We describe accomplishments of the EU project GLAMOROUS in making low-cost high performance electrooptic and nonlinear optical fibre- and waveguide-based components. In particular a comparison with more traditional...

  12. Low-NO{sub x}, wood chip combustion

    Energy Technology Data Exchange (ETDEWEB)

    Saastamoinen, J.; Oravainen, H.; Haemaelaeinen, J.; Paakkinen, K. [VTT Energy, Jyvaeskylae (Finland)

    1997-10-01

    The regulations for nitrogen oxide emissions vary in different countries, but the general trend in the future will probably be that the emissions limits will be lowered also for wood combustion plants, which are small or medium size units. Thus, the development of wood chip burning furnaces (grate furnaces, fluidized bed combustors, stoker furnaces) with lower nitrogen oxide emissions, is important. The wood used in the combustor, its particle size, moisture and fuel properties (nitrogen content) affect the nitrogen emissions. The nitrogen oxide release is also much affected by the design and operation of the combustor (air staging, fuel air preheat, flue gas circulation, air to fuel mass ratio). The fate of nitrogen compounds originally in the virgin wood depends much on the design of the combustor system and by proper planning it is possible to reduce the emission of nitrogen oxides. Basic knowledge of the release of nitrogen compounds from single wood particles is attained. The release of gaseous nitrogen compounds from wood particles during pyrolysis and combustion is studied experimentally and by modelling. Nitrogen release is studied experimentally by two ways, by analysing the gas and by quenching the particle and analysing the char residue. Formation of nitrogen oxide emissions in a fuel bed is studied by modelling and by combustion experiments with a pot furnace. This research gives general information of nitrogen oxide formation in wood bunting especially in fixed beds. The development of a horizontal stoker burner for wood chips with low emissions is the practical aim of the research. (orig.)

  13. Modeling Hurricane Katrina's merchantable timber and wood damage in south Mississippi using remotely sensed and field-measured data

    Science.gov (United States)

    Collins, Curtis Andrew

    Ordinary and weighted least squares multiple linear regression techniques were used to derive 720 models predicting Katrina-induced storm damage in cubic foot volume (outside bark) and green weight tons (outside bark). The large number of models was dictated by the use of three damage classes, three product types, and four forest type model strata. These 36 models were then fit and reported across 10 variable sets and variable set combinations for volume and ton units. Along with large model counts, potential independent variables were created using power transforms and interactions. The basis of these variables was field measured plot data, satellite (Landsat TM and ETM+) imagery, and NOAA HWIND wind data variable types. As part of the modeling process, lone variable types as well as two-type and three-type combinations were examined. By deriving models with these varying inputs, model utility is flexible as all independent variable data are not needed in future applications. The large number of potential variables led to the use of forward, sequential, and exhaustive independent variable selection techniques. After variable selection, weighted least squares techniques were often employed using weights of one over the square root of the pre-storm volume or weight of interest. This was generally successful in improving residual variance homogeneity. Finished model fits, as represented by coefficient of determination (R2), surpassed 0.5 in numerous models with values over 0.6 noted in a few cases. Given these models, an analyst is provided with a toolset to aid in risk assessment and disaster recovery should Katrina-like weather events reoccur.

  14. Partial transparency of compressed wood

    Science.gov (United States)

    Sugimoto, Hiroyuki; Sugimori, Masatoshi

    2016-05-01

    We have developed novel wood composite with optical transparency at arbitrary region. Pores in wood cells have a great variation in size. These pores expand the light path in the sample, because the refractive indexes differ between constituents of cell and air in lumen. In this study, wood compressed to close to lumen had optical transparency. Because the condition of the compression of wood needs the plastic deformation, wood was impregnated phenolic resin. The optimal condition for high transmission is compression ratio above 0.7.

  15. Car Side Structure Crashworthiness in Pole and Moving Deformable Barrier Side Impacts

    Institute of Scientific and Technical Information of China (English)

    WANG Dazhi; DONG Guang; ZHANG Jinhuan; HUANG Shilin

    2006-01-01

    To clearly understand passenger car structure's crashworthiness in typical side impacts of pole and moving deformable barrier (MDB) impact modes, which could assist the establishment of Chinese vehicle side impact safety regulations, a full midsized car finite element model, calibrated by pole side impact test, was built and the pole side impact according to European New Car Assessment Program (EuroNCAP) and the MDB side impact according to ECE R95 regulations were simulated with LS-DYNA. The accelerations and the structure deformations from simulations were compared. It can be concluded that the pole side impact focuses primarily on side structure crashworthiness as a result of large intrusions, while the MDB side impact focuses primarily on full side structure crashworthiness. Accordingly, occupant protection strategies focus on different aspects to improve side impact safety. In the pole side impact the objective is to maintain the passenger compartment and protect the passenger's head from impacting the pole, while in the MDB side impact the objective is to protect the full human body. In the design of the car side structures, at least these two tests should be considered for assessing their side impact crashworthiness. Conducting these two side impact tests as certified tests provides insights into car safety during side impacts.

  16. Understanding the role of the cytoskeleton in wood formation in angiosperm trees: hybrid aspen (Populus tremula x P. tremuloides) as a model species

    Energy Technology Data Exchange (ETDEWEB)

    Chaffey, N.; Barlow, P. [Bristol Univ., Dept. of Agricultural Sciences, Long Ashton, (United Kingdom); Sundberg, B. [Swedish Univ. of Agricultural Sciences, Dept. of Forest Genetics and Plant Physiology, Umea (Sweden)

    2002-03-01

    The involvement of microfilaments (MFs) and microtubules (MTs) in the development of the radial and axial components of secondary wood in hybrid aspen (Populus tremula X P. tremuloides) was studied by indirect immunofluorescent localization techniques in order to elucidate a consensus view of the roles of the cytoskeleton during wood formation in angiosperm trees. Early and late vessel elements, axial parenchyma, normal-wood fibres and contact and isolation cells were included in addition to cambial cells. Microfilaments were found to be rare in cambial cells, but were abundant and axially arranged in their derivatives once cell elongation begun. Microtubules were randomly oriented in ray and fusiform cells of the cambial zone. Ellipses of microfilaments were associated with pit development in fiber cells and isolation ray cells. Rings of localized microtubules and microfilaments were associated with developing inter-vessel bordered pits and vessel-contact ray cell contact pits. Although only microtubules were seen in the periphery of the perforation plate of vessel elements, a prominent meshwork of microfilaments overlaid the perforation plate itself. These observations indicate that there are corresponding subcellular control points whose manipulation could lead to the development of 'designer wood'. However, such development would require a better understanding of the physiological basis for the behaviour of microtubule and microfibre cytoskeletons during wood formation. 44 refs., 6 figs.

  17. Reactivity and burnout of wood fuels

    Energy Technology Data Exchange (ETDEWEB)

    Dall' Ora, M.

    2011-07-01

    pyrolysis temperature increased. During fast pyrolysis wood particles underwent melting, yet to different extents for the two investigated fuels: pine wood produced chars of porous spherical particles, whereas beech sawdust chars showed a somewhat less drastic change of morphology with respect to the parent fuel. Char produced by low heating rate pyrolysis fully retained the original fibrous structure of wood. Fast pyrolysis chars were significantly more reactive than slow pyrolysis chars (for the same activation energy, the pre-exponential factor was up to 2 orders of magnitude greater for chars increased). The amount and composition of the ash forming matter of the wood fuels is believed to play an important role in determining the differences in char yield, morphology and reactivity. The modelling of wood char combustion is the subject of Chapter 5. The lowest and the highest reactivities obtained for the chars produced in the EFR are used in a simple single particle combustion model in combination with a description of Avedoerevaerket's boiler. In the model the char particle is assumed to burn in a gas with constant temperature and constant oxygen fraction. The particle temperature is on the other hand determined taking reaction heat, convection through boundary gas layer and radiation into account. The model accounts for external diffusion of oxygen to the particle outer surface, internal diffusion in the pores and heterogeneous chemical reaction (CO is considered the only product). The model calculates an overall efficiency factor for combustion, yet assumes that all the reacting carbon is consumed at the outer surface of the char. The model predicts that at an average furnace temperature of 1200 K the conversion of char particles with radius 20-350 {micro}m is very much affected by the reactivity of the char. The influence of the particle's reactivity is lower at higher temperatures: at furnace temperatures of 1500 K and 1700 K the combustion of the char is

  18. Positive and Negative Thermal Poling of Germanosilicate Fibres

    DEFF Research Database (Denmark)

    Wong, D.; Wu, W.; Arentoft, Jesper;

    1999-01-01

    In situ measurements of thermal poling of germanosilicate fibers under positive and negative poling voltages show different dynamics of a linear electro-optic effect induced into fibers. The mechanism for the induced electro-optic effect is addressed......In situ measurements of thermal poling of germanosilicate fibers under positive and negative poling voltages show different dynamics of a linear electro-optic effect induced into fibers. The mechanism for the induced electro-optic effect is addressed...

  19. Consequences of increasing bioenergy demand on wood and forests: an application of the global forest products model

    Science.gov (United States)

    Joseph Buongiorno; Ronald Raunikar; Shushuai Zhu

    2011-01-01

    The Global Forest Products Model (GFPM) was applied to project the consequences for the global forest sector of doubling the rate of growth of bioenergy demand relative to a base scenario, other drivers being maintained constant. The results showed that this would lead to the convergence of the price of fuelwood and industrial roundwood, raising the price of industrial...

  20. Lunar Pole Illumination and Communications Statistics Computed from GSSR Elevation Data

    Science.gov (United States)

    Bryant, Scott

    2010-01-01

    The Goldstone Solar System RADAR (GSSR) group at JPL produced a Digital Elevation Model (DEM) of the lunar south pole using data obtained in 2006. This model has 40-meter horizontal resolution and about 5-meter relative vertical accuracy. This paper uses that Digital Elevation Model to compute average solar illumination and Earth visibility near the lunar south pole. This data quantifies solar power and Earth communications resources at proposed lunar base locations. The elevation data were converted into local terrain horizon masks, then converted into selenographic latitude and longitude coordinates. The horizon masks were compared to latitude, longitude regions bounding the maximum Sun and Earth motions relative to the moon. Proposed lunar south pole base sites were examined in detail, with the best site showing multi-year averages of solar power availability of 92% and Direct-To-Earth (DTE) communication availability of about 50%. Results are compared with a theoretical model, and with actual sun and Earth visibility averaged over the years 2009 to 2028. Results for the lunar North pole were computed using the GSSR DEM of the lunar North pole produced in 1997. The paper also explores using a heliostat to reduce the photovoltaic power system mass and complexity.

  1. 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.

  2. Determination of pole orientations and shapes of asteroids

    Science.gov (United States)

    Magnusson, Per; Barucci, M. Antonietta; Drummond, Jack D.; Lumme, Kari; Ostro, Steven J.

    1989-01-01

    The principles of asteroid light-curve inversion are discussed together with basic principles involved in approaches for deriving asteroid pole and shape parameters from photometry data. The merits of various pole determination techniques are described and compared. Results obtained so far on the pole orientations and shapes of asteroids are presented.

  3. 30 CFR 56.12048 - Communication conductors on power poles.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Communication conductors on power poles. 56... Electricity § 56.12048 Communication conductors on power poles. Telegraph, telephone, or signal wires shall not be installed on the same crossarm with power conductors. When carried on poles...

  4. Economics of Red Pine Management for Utility Pole Timber

    Science.gov (United States)

    Gerald H. Grossman; Karen Potter-Witter

    1991-01-01

    Including utility poles in red pine management regimes leads to distinctly different management recommendations. Where utility pole markets exist, managing for poles will maximize net returns. To do so, plantations should be maintained above 110 ft2/ac, higher than usually recommended. In Michigan's northern lower peninsula, approximately...

  5. 齿形木纤维柴油车尾气微粒捕集器过滤效率模型与试验%Filtering efficiency model and experiment of gear-shaped wood fiber diesel particle filter

    Institute of Scientific and Technical Information of China (English)

    郭秀荣; 杜丹丰; 亓占丰; 梁中钰; 刘跃雄

    2016-01-01

    Diesel engine is widely used in the fields of industrial and agricultural production and transportation for their good economy and dynamic performance. Unfortunately, diesel engines emit high quantities of particulate matter (PM) which is a potential risk to public health. Micron wood fiber is a kind of porous biological material that can be applied to filter PM emitted by diesel engine. In this paper, in order to increase the filtration efficiency and decrease filtration resistance, a wood fiber filter is developed, of which the internal structure is hollow and the external structure is like gear, and its advantages are low price, less requirement for diesel quality and large adsorption capacity for PM. In these respects, the gear-shaped wood fiber filter is promising in developing countries where the sulphur content is high in diesel oil. This gear-shaped wood fiber filter can be installed in a detachable DPF (diesel particle filter) whose temperature inside can be controlled below 220℃. First of all, based on the filter theory of fiber material, the filtration efficiency model of the gear-shaped wood fiber filter is established. Referring to the existing research and formula, the filtration efficiency of the gear-shaped wood fiber filter can be expressed by theoretical formula to be the function of wood fiber diameter, filling rate of wood fiber filter, thickness of filter and diameter of PM.Due to the diameter of PM ranging from 0.01 to 10μm and mainly concentrating at around 0.1μm, the recommended value of PMdiameter is 0.1μm. Then, through theoretical analysis and numerical calculation, the relationship curve between the filter efficiency and the influence factors is obtained. Lastly, a test bench of the filter performance is set up and used to verify the theoretical analysis results. In the test, we develope 10 gear-shaped wood fiber filters with different parameters according to the simulation results and set the speed and the load of the engine as 2

  6. Forest Management Effects on Channel Wood and Wood-Channel Interactions in Caspar Creek, California

    Science.gov (United States)

    Hilton, S.

    2006-12-01

    . Mean bed elevations have been decreasing, particularly in areas with little wood. Much of the wood in both channels was mobilized by high flows in HY 2005. LWD input, survival, and mobility data, along with channel-adjacent stand information and growth models, allow estimation of future LWD in these channels and of how that wood might affect channel behavior.

  7. Modeling of Mechanical Properties for Amorphous Nanocellulose of Wood%非晶态木质纳米纤维素机械特性的建模

    Institute of Scientific and Technical Information of China (English)

    张秀梅; 曹军; 仇逊超; Mark A Tschopp; Mark Horstemeyer; Sheldon Shi

    2012-01-01

    为提高对以木纤维为填充材料的复合材料的理解和性能分析,对木质纳米纤维素中的非晶态结构进行分子建模与拉伸变形仿真研究.通过对纳米纤维素非晶态结构进行周期性边界条件建模,在能量最小化和热平衡后,基于ReaxFF力场用开源代码程序LAMMPS对模型进行拉伸变形仿真,模拟原子间的相互作用,对其数据结果采用MATLAB进行后处理分析,并采用可视化开源软件Atomeye对变形过程进行监控.通过所建模型仿真研究数据,可以计算得到木质纳米纤维素纳观尺度的机械特性,求得纳观结构中应力一应变曲线,将其同实验数据相比较,用于预测材料宏观尺度各特性以及本构关系.该研究为今后分析高分子聚合物和纤维素的纳米微观界面相容性打下基础,能更好地理解高分子纤维聚合材料的力学性能.%The research objective is to gain a better fundamental understanding of the mechanical behavior of cellulose structure in wood microfiber for enhancing the mechanical properties of ceIIulosic-based composites. Molecular static and molecular dynamics simulations were used to both generate and deform the amorphous cellulose structure in a three-dimensional periodic simulation cell. The 14-p-D-glucose structure was chosen along with a reactive force field, ReaxFF, to model the atomic interactions and complex bonding of cellulose. Mechanical properties were calculated for these models, and the predicted geometric, energetic and elastic material properties were compared to the published modeling results and experimental measurements. The significance of the research is that this sets the stage for future polymer-cellulose predictive microme-chanical models. These predictive models can be used to elucidate the interfacial compatibility between the cellulose and polymer, which is helpful in understanding how deposited nanoparticles and nanophases on cellulose surfaces affect this

  8. The 10 Meter South Pole Telescope

    CERN Document Server

    Carlstrom, J E; Aird, K A; Benson, B A; Bleem, L E; Busetti, S; Chang, C L; Chauvin, E; Cho, H -M; Crawford, T M; Crites, A T; Dobbs, M A; Halverson, N W; Heimsath, S; Holzapfel, W L; Hrubes, J D; Joy, M; Keisler, R; Lanting, T M; Lee, A T; Leitch, E M; Leong, J; Lu, W; Lueker, M; McMahon, J J; Mehl, J; Meyer, S S; Mohr, J J; Montroy, T E; Padin, S; Plagge, T; Pryke, C; Ruhl, J E; Schaffer, K K; Schwan, D; Shirokoff, E; Spieler, H G; Staniszewski, Z; Stark, A A; Vieira, K Vanderlinde J D

    2009-01-01

    The South Pole Telescope (SPT) is a 10 m diameter, wide-field, offset Gregorian telescope with a 966-pixel, multi-color, millimeter-wave, bolometer camera. It is located at the Amundsen-Scott South Pole station in Antarctica. The design of the SPT emphasizes careful control of spillover and scattering, to minimize noise and false signals due to ground pickup. The key initial project is a large-area survey at wavelengths of 3, 2 and 1.3 mm, to detect clusters of galaxies via the Sunyaev-Zeldovich (SZ) effect and to measure the high-l angular power spectrum of the cosmic microwave background (CMB). The data will be used to characterize the primordial matter power spectrum and to place constraints on the equation of state of dark energy.

  9. Pole Placement with Fields of Positive Characteristic

    CERN Document Server

    Gorla, Elisa

    2009-01-01

    The pole placement problem belongs to the classical problems of linear systems theory. It is often assumed that the ground field is the real numbers R or the complex numbers C. The major result over the complex numbers derived in 1981 by Brockett and Byrnes states that arbitrary static pole placement is possible for a generic set of m-inputs, p-outputs and McMillan degree n system as soon as mp>=n. Moreover the number of solutions in the situation mp=n is an intersection number first computed by Hermann Schubert in the 19th century. In this paper we show that the same result with slightly different proofs holds over any algebraically closed field.

  10. Surface Free Energy and Dynamic Wettability of Differently Machined Poplar Woods

    Directory of Open Access Journals (Sweden)

    Zhiyong Qin

    2014-04-01

    Full Text Available The surface free energy and dynamic wettability of wood are important to the performance of its adhesive bonding strength. In this work, the surface free energy of poplar wood samples machined with different processes were calculated by the OWRK (geometric mean and vOCG (acid-base methods, and the dynamic wettability of adhesives on wood samples was studied using the S-D wetting model. The results indicate that the contact angles of reference liquids on rotary wood samples were greater than those on planed or sawn wood, and the rotary wood samples were more hydrophobic. The effect of surface roughness on contact angle was insignificant compared with surface structure morphology. The total surface free energy was almost the same for the planed and sawn wood, as calculated by the OWRK and vOCG methods, and the surface free energy of rotary wood samples was lower than that of planed or sawn wood samples. The initial and equilibrium contact angle increased as the viscosity of adhesive increased for all the wood samples, and the contact angles of rotary wood samples were greater than those of planed or sawn wood; however, the K-value was lower. The wettability of the loose side was higher than that of the tight side. Contact angles decreased when surface free energy increased, while the K-value increased.

  11. Pole Assignment for Second-Order Systems

    Science.gov (United States)

    CHU, E. K.

    2002-01-01

    This paper contains some results for pole assignment problems for the second-order system M ẍ(t)+D ẋ(t)+K x (t)=B u (t) . Specifically, Algorithm 0 constructs feedback matrices F1 and F2 such that the closed-loop quadratic pencil Pc( λ)= λ2M+ λ ( D+ BF2)+( K+ BF1) has a desired set of eigenvalues and the associated eigenvectors are well-conditioned. The method is a modification of the SVD-based method proposed by Juang and Maghami [1, 2] which is a second-order adaptation of the well-known robust eigenvalue assignment method by Kautsky et al. [3] for first-order systems. Robustness is achieved by minimising some not-so-well-known condition numbers of the eigenvalues of the closed-loop second-order pencil. We next consider the partial pole assignment problem. In 1997, Datta, Elhay and Ram proposed three biorthogonality relations for eigenvectors of symmetric definite quadratic pencils [4]. One of these relations was used to derive an explicit solution to the partial pole assignment problem by state feedback for the related single-input symmetric definite second-order control system. The solution shed new light on the stabilisation and control of large flexible space structures, for which only one small subset of the spectrum needs to be reassigned while retaining the complementary part of the spectrum. In this paper, the method has been generalised for multi-input and non-symmetric quadratic pencils. Finally, we discuss briefly the output feedback pole assignment problem.

  12. Efficient iterative adaptive pole placement algorithm

    Institute of Scientific and Technical Information of China (English)

    李俊民; 李靖; 杨磊

    2004-01-01

    An iterative adaptive pole placement algorithm is presented. The stability and the convergence of the algorithm are respectively established. Since one-step iterative formulation in computing controller's parameters is used, the on-line computation cost is greatly reduced with respected to the traditional algorithm. The algorithm with the feed-forward can follow arbitrarily bounded output. The algorithm is also extended to multivariate case. Simulation examples show the efficiency and robustness of the algorithm.

  13. The South Pole and the Ross Sea

    Science.gov (United States)

    2002-01-01

    This image shows a rare clear view of the South Pole (lower right) and the Ross Sea, Antarctica. The Sea-viewing Wide Field-of-view Sensor (SeaWiFS) acquired the scene on December 26, 2001. The geographic South Pole is located in the center of Antarctica, at an altitude of 2,900 meters (9,300 feet). It rests on a continent-wide ice sheet that is 2,870 m thick, with the underlying bedrock only 30 m (98 feet) above sea level. The ice underlying the South Pole is as much as 140,000 years old, and is currently accumulating at about 82 cm (32 inches) per year. Roughly 2,500 km (1,550 miles) away is the green water of the Ross Sea, which indicates the presence of large numbers of phytoplankton. This is a highly productive part of the world's oceans. Also note the ice gathered around McMurdo Sound, seen toward the lefthand shoreline of the Ross Sea, at the edge of the Ross Ice Shelf. According to National Science Foundation researchers, this ice is making it difficult for penguins to reach their food supply. Separating the continental Antarctic ice sheet from the Ross Sea are the Queen Maud Mountains and the Ross Ice Shelf. Image courtesy the SeaWiFS Project, NASA/Goddard Space Flight Center, and ORBIMAGE

  14. Ambient wood smoke exposure and respiratory symptoms in Tasmania, Australia.

    Science.gov (United States)

    Bennett, C M; Dharmage, S C; Matheson, M; Gras, J L; Markos, J; Mészáros, D; Hopper, J; Walters, E H; Abramson, M J

    2010-12-15

    Wood smoke exposure has been associated with adverse respiratory health outcomes, with much of the current research focused on wood smoke from domestic heating and cooking. This study examined the association between respiratory symptoms and outdoor wood smoke in Launceston, Tasmania, where ~30% of homes use wood burners for domestic heating. This ecological study examined data from participants of the 2004 Tasmanian Longitudinal Health Study postal survey and compared the prevalence of respiratory symptoms in Launceston (n=601) with that in Hobart (n=1071), a larger Tasmanian city with much less wood smoke. Multivariate logistic regression models were used to investigate the associations of interest while adjusting for gender, atopy, history of allergic disease and current smoking status. There were no significant differences in symptom prevalence between Launceston and Hobart. Two subgroup analyses, which examined participants with pre-existing chronic respiratory disease, and those who reported actively using a wood burner in their home, also did not find significant differences. Any impact of wood smoke on non-specific respiratory symptoms might have been overshadowed by other important determinants of respiratory health, such as vehicle exhaust and tobacco smoking, or were too small to have been detected. However, the lack of detectable differences in symptom prevalence might also reflect the success of regulatory action by local governments to reduce wood smoke emissions in Launceston. The results of other epidemiological studies support an association between ambient wood smoke exposure and adverse respiratory health. Further investigations of wood smoke exposure in Australian settings are needed to investigate the lack of significant associations found in this study, especially studies of indoor air quality and health impacts in children and elderly populations.

  15. Calculating broad neutron resonances in a cut-off Woods-Saxon potential

    CERN Document Server

    Baran, Á; Salamon, P; Vertse, T

    2015-01-01

    In a cut-off Woods-Saxon potential with realistic depth $S$-matrix poles being far from the imaginary wave number axis form a sequence where the distances of the consecutive resonances are inversely proportional with the cut-off radius value. Other poles lying closer to the imaginary wave number axis might have trajectories with irregular shapes as the depth of the potential increases. Poles being close repel each other, and their repulsion is responsible for the changes of the directions of the corresponding trajectories. The interaction is extremely sensitive to the cut-off radius value. The repulsion might cause that certain resonances become antibound and later resonances again when they collide on the imaginary axis.

  16. Calculating broad neutron resonances in a cut-off Woods-Saxon potential

    Energy Technology Data Exchange (ETDEWEB)

    Baran, A.; Noszaly, Cs. [Faculty of Informatics, University of Debrecen, PO Box 12, Debrecen (Hungary); Salamon, P. [Hungarian Academy of Sciences (ATOMKI), Institute for Nuclear Research, PO Box 51, Debrecen (Hungary); Vertse, T. [Faculty of Informatics, University of Debrecen, PO Box 12, Debrecen (Hungary); Hungarian Academy of Sciences (ATOMKI), Institute for Nuclear Research, PO Box 51, Debrecen (Hungary)

    2015-07-15

    In a cut-off Woods-Saxon (CWS) potential with realistic depth S -matrix poles being far from the imaginary wave number axis form a sequence where the distances of the consecutive resonances are inversely proportional with the cut-off radius value, which is an unphysical parameter. Other poles lying closer to the imaginary wave number axis might have trajectories with irregular shapes as the depth of the potential increases. Poles being close repel each other, and their repulsion is responsible for the changes of the directions of the corresponding trajectories. The repulsion might cause that certain resonances become antibound and later resonances again when they collide on the imaginary axis. The interaction is extremely sensitive to the cut-off radius value, which is an apparent handicap of the CWS potential. (orig.)

  17. Simulated wood budgets in two mountain streams

    Science.gov (United States)

    Hassan, Marwan A.; Bird, Stephen; Reid, David; Hogan, Daniel

    2016-04-01

    Large wood (LW) recruitment, transport, and storage were evaluated over a century in Gregory and Riley creeks (Haida Gwaii, British Columbia) by modeling a reach-scale LW budget using two frameworks for output: LW loss through decay and downstream transport, and loss through depletion. At reach and at watershed scales, mass movement and bank erosion dominated inputs, and fluvial transport was an important flux term in several reaches. Large wood recruitment by mortality was relatively minor in comparison. Large proportions of the in-channel LW were stored in jams with a mean age of 40-50 years. Overall, both modeling approaches yielded reasonable stored LW predictions in the study creeks, with the omission/inclusion of transport responsible for the largest differences between models. Modeled storage generally was within 30% of that measured in the field, and our results illustrate the large temporal variation in storage resulting from episodic inputs of LW from hillslopes.

  18. The trait contribution to wood decomposition rates of 15 Neotropical tree species.

    Science.gov (United States)

    van Geffen, Koert G; Poorter, Lourens; Sass-Klaassen, Ute; van Logtestijn, Richard S P; Cornelissen, Johannes H C

    2010-12-01

    The decomposition of dead wood is a critical uncertainty in models of the global carbon cycle. Despite this, relatively few studies have focused on dead wood decomposition, with a strong bias to higher latitudes. Especially the effect of interspecific variation in species traits on differences in wood decomposition rates remains unknown. In order to fill these gaps, we applied a novel method to study long-term wood decomposition of 15 tree species in a Bolivian semi-evergreen tropical moist forest. We hypothesized that interspecific differences in species traits are important drivers of variation in wood decomposition rates. Wood decomposition rates (fractional mass loss) varied between 0.01 and 0.31 yr(-1). We measured 10 different chemical, anatomical, and morphological traits for all species. The species' average traits were useful predictors of wood decomposition rates, particularly the average diameter (dbh) of the tree species (R2 = 0.41). Lignin concentration further increased the proportion of explained inter-specific variation in wood decomposition (both negative relations, cumulative R2 = 0.55), although it did not significantly explain variation in wood decomposition rates if considered alone. When dbh values of the actual dead trees sampled for decomposition rate determination were used as a predictor variable, the final model (including dead tree dbh and lignin concentration) explained even more variation in wood decomposition rates (R2 = 0.71), underlining the importance of dbh in wood decomposition. Other traits, including wood density, wood anatomical traits, macronutrient concentrations, and the amount of phenolic extractives could not significantly explain the variation in wood decomposition rates. The surprising results of this multi-species study, in which for the first time a large set of traits is explicitly linked to wood decomposition rates, merits further testing in other forest ecosystems.

  19. Pole-placement with constant gain output feedback

    Science.gov (United States)

    Sridhar, B.; Lindorff, D. P.

    1973-01-01

    Davison (1970) has demonstrated that it is possible to assign max (m, p) poles of a linear time-invariant controllable and observable multivariable system arbitrarily close to desired locations by using constant gain output feedback. A new proof of Davison's theorem on pole placement is developed, and a system design procedure is described which offers some advantages over Davison's method. It is shown that in some cases more than max (m, p) poles can be assigned arbitrarily, and a least square design procedure is proposed to approximate the desired pole locations when it is not possible to place all the poles.

  20. Controlling mold on wood Pallets

    Science.gov (United States)

    Carol A. Clausen

    2012-01-01

    THE WOOD PALLET AND CONTAINER INDUSTRY CONSUMES 4.5 billion board feet (BBF) of hardwoods and 1.8 BBF of softwoods for the annual production of 400-500 million solid wood pallets. While alternative materials such as plastic, corrugated paperboard and metal have entered the market, solid wood remains the material of choice for a majority of pallets on the market (more...

  1. Ground Wood Fiber Length Distributions

    OpenAIRE

    Lauri Ilmari Salminen; Sari Liukkonen; Alava, Mikko J.

    2014-01-01

    This study considers ground wood fiber length distributions arising from pilot grindings. The empirical fiber length distributions appear to be independent of wood fiber length as well as feeding velocity. In terms of mathematics the fiber fragment distributions of ground wood pulp combine an exponential distribution for high-length fragments and a power-law distribution for smaller lengths. This implies that the fiber length distribution is influenced by the stone surface. A fragmentation-ba...

  2. GIS-based Decision Support System for Wood Logistics

    Institute of Scientific and Technical Information of China (English)

    Qiu Rongzu1; Esko Mikkonen

    2004-01-01

    A wood logistics system was combined with a linear programming (LP) method utilizing GIS-based techniques on the platform of GIS software-ARC/INFO. The combined costs of road and off-road transport were taken as the objective function to find the least cost route and the optimal landing locations of wood transportation. Then transport costs and allowable wood volume of stands were calculated. An LP model was developed to allocate timber resources among mills in order to minimize the wood logistics costs from harvesting sites to mills. The parameters of the LP model, including the transport costs, allowable wood volume and wood orders, were written into a text file in MPS format which were then accessed by LINDO to solve the LP problem. The system is an effective tool to manage logistics, information and funds together in order to increase the speed of wood logistics and reduce the cost. The benefits and efficiency of mill cluster can be improved. The focal firm in the cluster can be competitive.

  3. Factors influencing wood mobilization 1 in Minnesota streams

    Science.gov (United States)

    Merten, Eric; Finlay, Jacques; Johnson, Lucinda; Newman, Raymond; Stefan, Heinz; Vondracek, Bruce C.

    2010-01-01

    [1] Natural pieces of wood provide a variety of ecosystem functions in streams including habitat, organic matter retention, increased hyporheic exchange and transient storage, and enhanced hydraulic and geomorphic heterogeneity. Wood mobilization is a critical process in determining the residence time of wood. We documented the characteristics and locations of 865 natural wood pieces (>0.05 m in diameter for a portion >1 m in length) in nine streams along the north shore of Lake Superior in Minnesota. We determined the locations of the pieces again after an overbank stormflow event to determine the factors that influenced mobilization of stationary wood pieces in natural streams. Seven of 11 potential predictor variables were identified with multiple logistic regression as significant to mobilization: burial, effective depth, ratio of piece length to effective stream width (length ratio), bracing, rootwad presence, downstream force ratio, and draft ratio. The final model (Pmobilization under natural conditions is a complex function of both mechanical factors (burial, length ratio, bracing, rootwad presence, draft ratio) and hydraulic factors (effective depth, downstream force ratio). If stable pieces are a goal for stream management then features such as partial burial, low effective depth, high length relative to channel width, bracing against other objects (e.g., stream banks, trees, rocks, or larger wood pieces), and rootwads are desirable. Using the model equation from this study, stewards of natural resources can better manage in-stream wood for the benefit of stream ecosystems.

  4. Growth Poles - an Alternative to Reducing Regional Disparities. Case Study-Iaşi Growth Pole

    Directory of Open Access Journals (Sweden)

    NICOLETA MONICA MUSTĂȚEA

    2013-01-01

    Full Text Available The current development of the European Union is based on the cohesion policy which focuses on the attenuation of regional disparities. For this purpose, the idea of growth poles emerged in Romania, and its role became more than familiar: the determination of an internal socio-economic cohesion. Polycentrism becomes a concept of territorial planning increasingly promoted. Development of growth poles aims to reduce the attraction force of large centres and to balance the location of activities generating functions across a territory. This was the idea that led to the formation of Iaşi Metropolitan Area, territorial unit that is intended to be the main regional centre of the North-East Region, thus polarizing the surrounding areas. Iaşi Growth Pole objectives are represented by economic competitiveness, the development of regional connectivity and the promotion of regional cooperation. One of the major assets of the growth pole in achieving these goals is the cross-border position near the eastern border of the European Union. This paper examines to what extent Iași Growth Pole can rise to the required standards, while the peripheral position seems to be rather a disadvantage and the uncertain functionality of the metropolitan area shows that the main problem remains the reduced economic competitiveness.

  5. Modeling Wood Density with Two-Level Linear Mixed Effects Models for Dahurian Larch%基于2层次线性混合模型的落叶松木材密度模拟

    Institute of Scientific and Technical Information of China (English)

    李耀翔; 姜立春

    2013-01-01

    以黑龙江省七台河市林业局金沙林场9株人工落叶松432个样品密度数据为例,利用逐步回归技术构建落叶松木材密度模型:WD=β1+β2RN+β3RN2+β4h.利用S-PLUS软件中的LME过程,分别考虑单水平和多水平效应,拟合线性木材密度混合效应模型.结果表明:基于单水平和多水平效应的混合模型拟合精度高于传统的基本模型,并且考虑单水平树高效应和2层次效应时的混合模型精度高于考虑单水平样木效应影响的混合模型.模型检验结果表明:混合效应模型不但能反映总体平均木材密度变化趋势,还能反映分组之间的差异.%In this study,the sample data was based on 432 samples of 9 trees from dahurian larch(Larix gmelinii) plantations located in Qitaihe Forest Bureau in Heilongjiang Province.The stepwise regression techniques were used to develop wood density model:WD =β1 +β2RN +β3RN2 +β4h.Then,the developed model was fitted using single level and multilevel linear mixed-effects modeling approach based on LME procedure of S-PLUS software.The mixed effects models showed better model fitting results than basic model whatever considering single level and multilevel linear mixed effects.Moreover,the mixed effects model considering height effects and both effects showed more precision than that considering individual tree effects.Model test indicated that mixed effects models not only showed the mean trends of wood density,but also showed the variations among groups.

  6. Implementing Strategies for Drying and Pressing Wood Without Emissions Controls

    Energy Technology Data Exchange (ETDEWEB)

    Sujit Banerjee; Terrance Conners

    2007-09-07

    Drying and pressing wood for the manufacture of lumber, particleboard, oriented strand board (OSB), veneer and medium density fiberboard (MDF) release volatile organic compounds (VOCs) into the atmosphere. These emissions require control equipment that are capital-intensive and consume significant quantities of natural gas and electricity. The objective of our work was to understand the mechanisms through which volatile organic compounds are generated and released and to develop simple control strategies. Of the several strategies developed, two have been implemented for OSB manufacture over the course of this study. First, it was found that increasing final wood moisture by about 2-4 percentage points reduced the dryer emissions of hazardous air pollutants by over 70%. As wood dries, the escaping water evaporatively cools the wood. This cooling tapers off wood when the wood is nearly dry and the wood temperature rises. Thermal breakdown of the wood tissue occurs and VOCs are released. Raising the final wood moisture by only a few percentage points minimizes the temperature rise and reduces emissions. Evaporative cooling also impacts has implications for VOC release from wood fines. Flaking wood for OSB manufacture inevitable generates fines. Fines dry out rapidly because of their high surface area and evaporative cooling is lost more rapidly than for flakes. As a result, fines emit a disproportionate quantity of VOCs. Fines can be reduced in two ways: through screening of the green furnish and through reducing their generation during flaking. The second approach is preferable because it also increased wood yield. A procedure to do this by matching the sharpness angle of the flaker knife to the ambient temperature was also developed. Other findings of practical interests are as follows: Dielectric heating of wood under low-headspace conditions removes terpenes and other extractives from softwood; The monoterpene content in trees depend upon temperature and seasonal

  7. Wet air oxidation of resorcinol as a model treatment for refractory organics in wastewaters from the wood processing industry.

    Science.gov (United States)

    Weber, Bernd; Chavez, Alma; Morales-Mejia, Julio; Eichenauer, Sabrina; Stadlbauer, Ernst A; Almanza, Rafael

    2015-09-15

    Wastewater treatment systems are important tools to enhance sustainability in terms of reducing environmental impact and complying with sanitary requirements. This work addresses the wet air oxidation (WAO) process for pre-treatment of phenolic wastewater effluents. The aim was to increase biodegradability prior to a subsequent anaerobic stage. In WAO laboratory experiments using a micro-autoclave, the model compound resorcinol was degraded under different oxygen availability regims within the temperature range 150 °C-270 °C. The activation energy was determined to be 51.5 kJ/mol. Analysis of the products revealed that after 3 h of reaction at 230 °C, 97.5% degradation of resorcinol was achieved. At 250 °C and the same reaction time complete removal of resorcinol was observed. In this case the total organic carbon content was reduced down to 29%, from 118.0 mg/L down to 34.4 mg/L. Under these process conditions, the pollutant was only partially mineralized and the ratio of the biological oxygen demand relative to the chemical oxygen demand, which is 0.07 for resorcinol, was increased to a value exceeding 0.5. The main by-product acetic acid, which is a preferred compound for methanogenic bacteria, was found to account for 33% of the total organic carbon.

  8. Energy harvesting using AC machines with high effective pole count

    Science.gov (United States)

    Geiger, Richard Theodore

    In this thesis, ways to improve the power conversion of rotating generators at low rotor speeds in energy harvesting applications were investigated. One method is to increase the pole count, which increases the generator back-emf without also increasing the I2R losses, thereby increasing both torque density and conversion efficiency. One machine topology that has a high effective pole count is a hybrid "stepper" machine. However, the large self inductance of these machines decreases their power factor and hence the maximum power that can be delivered to a load. This effect can be cancelled by the addition of capacitors in series with the stepper windings. A circuit was designed and implemented to automatically vary the series capacitance over the entire speed range investigated. The addition of the series capacitors improved the power output of the stepper machine by up to 700%. At low rotor speeds, with the addition of series capacitance, the power output of the hybrid "stepper" was more than 200% that of a similarly sized PMDC brushed motor. Finally, in this thesis a hybrid lumped parameter / finite element model was used to investigate the impact of number, shape and size of the rotor and stator teeth on machine performance. A typical off-the-shelf hybrid stepper machine has significant cogging torque by design. This cogging torque is a major problem in most small energy harvesting applications. In this thesis it was shown that the cogging and ripple torque can be dramatically reduced. These findings confirm that high-pole-count topologies, and specifically the hybrid stepper configuration, are an attractive choice for energy harvesting applications.

  9. Second sheet $\\sigma$-pole and the threshold enhancement of the spectral function in the scalar-isoscalar meson-sector

    CERN Document Server

    Patkós, András; Szépfalusy, P; Szep, Zs.

    2002-01-01

    The relationship between the scalar-isoscalar spectral function and the second Riemann sheet pole in the same channel is analyzed in an effective linear $\\sigma$-model with help of an expansion in the number of the Goldstone-bosons. A generic scenario is suggested for the temperature/density driven evolution of the pole location. An extended temperature range, correlated with characteristic pole locations, is found where the phenomenon of threshold enhancement takes place in the spectral function.

  10. Purification of fluorescently labeled Saccharomyces cerevisiae Spindle Pole Bodies

    Science.gov (United States)

    Davis, Trisha N.

    2016-01-01

    Centrosomes are components of the mitotic spindle responsible for organizing microtubules and establishing a bipolar spindle for accurate chromosome segregation. In budding yeast, Saccharomyces cerevisiae, the centrosome is called the spindle pole body, a highly organized tri-laminar structure embedded in the nuclear envelope. Here we describe a detailed protocol for the purification of fluorescently labeled spindle pole bodes from S. cerevisiae. Spindle pole bodies are purified from yeast using a TAP-tag purification followed by velocity sedimentation. This highly reproducible TAP-tag purification method improves upon previous techniques and expands the scope of in vitro characterization of yeast spindle pole bodies. The genetic flexibility of this technique allows for the study of spindle pole body mutants as well as the study of spindle pole bodies during different stages of the cell cycle. The ease and reproducibility of the technique makes it possible to study spindle pole bodies using a variety of biochemical, biophysical, and microscopic techniques. PMID:27193850

  11. Model-Based Throttle Control using Static Compensators and Pole Placement Commande des gaz basée sur un modèle utilisant des compensateurs statiques et un placement de pôles

    Directory of Open Access Journals (Sweden)

    Thomasson A.

    2011-10-01

    Full Text Available In modern spark ignited engines, the throttle is controlled by the Electronic Control Unit (ECU, which gives the ECU direct control of the air flow and thereby the engine torque. This puts high demands on the speed and accuracy of the controller that positions the throttle plate. The throttle control problem is complicated by two strong nonlinear effects, friction and limp-home torque. This paper proposes the use of two, simultaneously active, static compensators to counter these effects and approximately linearize the system. A PID controller is designed for the linearized system, where pole placement is applied to design the PD controller and a gain scheduled I-part is added for robustness against model errors. A systematic procedure for generating compensator and controller parameters from open loop experiments is also developed. The controller performance is evaluated both in simulation, on a throttle control benchmark problem, and experimentally. A robustness investigation pointed out that the limp-home position is an important parameter for the controller performance, this is emphasized by the deviations found in experiments. The proposed method for parameter identification achieves the desired accuracy. Au sein des moteurs à allumage commandé modernes, les gaz sont régulés par le boîtier de commande électronique (ECU; Electronic Control Unit, qui permet la régulation directe par l’ECU du flux d’air et ainsi du couple moteur. Cela conduit à des exigences élevées quant à la vitesse et à la précision du régulateur qui positionne le papillon des gaz. Le problème de commande des gaz est compliqué par deux forts effets non linéaires, le frottement et le couple de mode de secours (“limp-home”. Cet article propose l’utilisation de deux compensateurs statiques, actifs simultanément, pour contrer ces effets et linéariser approximativement le système. Un régulateur PID est conçu pour le système linéarisé, où un

  12. Elemental Mercury Diffusion Processes and Concentration at the Lunar Poles

    Science.gov (United States)

    Moxley, Frederick; Killen, Rosemary M.; Hurley, Dana M.

    2011-01-01

    In 2009, the Lyman Alpha Mapping Project (LAMP) spectrograph onboard the Lunar Reconnaissance Orbiter (LRO) spacecraft made the first detection of element mercury (Hg) vapor in the lunar exosphere after the Lunar Crater Observing and Sensing Satellite (LCROSS) Centaur rocket impacted into the Cabeus crater in the southern polar region of the Moon. The lunar regolith core samples from the Apollo missions determined that Hg had a devolatilized pattern with a concentration gradient increasing with depth, in addition to a layered pattern suggesting multiple episodes of burial and volatile loss. Hg migration on the lunar surface resulted in cold trapping at the poles. We have modeled the rate at which indigenous Hg is lost from the regolith through diffusion out of lunar grains. We secondly modeled the migration of Hg vapor in the exosphere and estimated the rate of cold-trapping at the poles using a Monte Carlo technique. The Hg vapor may be lost from the exosphere via ionization, Jeans escape, or re-impact into the surface causing reabsorption.

  13. Elliptical Chandler pole motions of the Earth and Mars

    Science.gov (United States)

    Barkin, Yury; Ferrandiz, Jose

    2010-05-01

    In the work the values of the period and eccentricity of Chandler motion of poles of axes of rotation of the Earth and Mars have been determined. The research has been carried out on the basis of developed earlier by authors an intermediate rotary Chandler-Euler motion of the weakly deformable celestial bodies (Barkin, Ferrandiz and Getino, 1996; Barkin, 1998). An influence of a liquid core on Chandler motion of a pole in the given work has not considered. The periods of the specified pole motions make 447.1 d for the Earth and 218.1 d for Mars. In comparison with Euler motions of poles because of elastic properties of planets the Chandler periods are increased accordingly on 142.8 d (about 46.9 %) for the Earth and on 26.2 d (on 13.7 %) for Mars. Values of eccentricities of specified Chandler motions of pole e = √b2 --a2- b (here a both b are smaller and big semi-axes of Chandler ellipse) make 0.09884 for the Earth and 0.3688 for Mars (accordingly, on 21.1 % and 6.2 % more than the appropriate values of eccentricities for models of planets as rigid non-spherical bodies). Axes of an ellipse a also b correspond to the principal equatorial axes of inertia of a planet Ox and Oyfor which the moments of inertia have the smallest valueA and middle value B. The pole of the principal axis of inertia Ox for the Earth is displaced to the west on the angle 14°9285, and the pole of the principal axis of inertia Ox for Mars is displaced to the west on the angle 105°0178 (in the appropriate basic geographical systems of coordinates of the given planets). For ellipticties of Chandler trajectories ɛ = (b- a)-b the values 0.004897 (for the Earth) and 0.07048 (for Mars) have been obtained. The specified values surpass by Euler values of appropriate ellipticties on 46.8 % (in case of the Earth) and on 13.3 % (in the case of Mars). Love number k2describing the elastic properties of planets, were accepted equal 0.30 for the Earth and 0.153 for Mars. Estimations of Chandler periods

  14. Five-Phase Modular External Rotor PM Machines with Different Rotor Poles: A Comparative Simulation Study

    Directory of Open Access Journals (Sweden)

    A. S. Abdel-Khalik

    2012-01-01

    Full Text Available The performance of fault-tolerant modular permanent magnet machines depends on the proper selection of the pole and slot numbers which result in negligible coupling between phases. The preferred slot and pole number combinations eliminate the effect of low-order harmonics in the stator magnetomotive force and thereby the vibration and stray loss are reduced. In this paper, three external rotor machines with identical machine dimensions are designed with different slots per phase per pole ratios. A simulation study is carried out using finite element analysis to compare the performance of the three machines in terms of machine torque density, ripple torque, core loss, and machine efficiency. A mathematical model based on the conventional-phase-model approach is also used for the comparative study. The simulation study is extended to depict machine performance under fault conditions.

  15. Performance evaluation of a five-phase modular external rotor PM machine with different rotor poles

    Directory of Open Access Journals (Sweden)

    A.S. Abdel-Khalik

    2012-12-01

    Full Text Available The performance of fault-tolerant modular permanent magnet (PM machines depends on the proper selection of the pole and slot numbers which result in negligible coupling between phases. The preferred slot and pole number combinations eliminate the effect of low order harmonics in the stator magneto motive force and thereby the vibration and stray loss are reduced. In this paper, three external rotor machines with identical machine dimensions are designed with different slots per phase per pole (SPP ratios. A simulation study is carried out using finite element analysis to compare the performance of the three machines in terms of machine torque density, ripple torque, core loss, and machine efficiency. A mathematical model based on the conventional phase model approach is also used for the comparative study. The simulation study is extended to depict machine performance under fault conditions.

  16. 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...

  17. WAVET*, a custom device able to measure viscoelastic properties of wood under water saturated conditions (*WAVET : Environmental Vibration Analyser for Wood)

    CERN Document Server

    Placet, Vincent; Perré, Patrick

    2009-01-01

    This work presents an original experimental device conceived to characterise the viscoelastic properties of wood. Classically, the dynamic mechanical analysis of wood is performed using a commercial apparatus like a DMA (Dynamic Mechanical Analyser). However, when analysing wood with this type of apparatus, many problems related to the hygroscopic behaviour and the orthotropic structure of wood may be encountered. This is why an original apparatus perfectly adapted to the wood features has been developed. The WAVET is able to measure the viscoelastic properties of wood samples under water-saturated conditions, in the temperature range of 5\\degree C to 95\\degree C at frequencies varying between 0.005 Hz and 10 Hz. Samples are tested in a cantilever configuration. The whole experiment has been designed to withstand the severe conditions of temperature and humidity. At the same time, an analytical model based on Kelvin's elements has been developed. This model is able to correct experimental measurements perform...

  18. Design and analysis of a transversal-flux switched-reluctance-linear-machine pole-pair

    Energy Technology Data Exchange (ETDEWEB)

    Salo, J.

    1999-07-01

    The Switched Reluctance technology is probably best suited for industrial low-speed or zerospeed applications where the power can be small but the torque or the force in linear movement cases might be relatively high. Because of its simple structure the Sit-motor is an interesting alternative for low power applications where pneumatic or hydraulic linear drives are to be avoided. This study analyses the basic parts of an LSR-motor which are the two mover poles and one stator pole and which form the 'basic pole pair' in linear-movement transversal-flux switched-reluctance motors. The static properties of the basic pole pair are modelled and the basic design rules are derived. The models developed are validated with experiments. A one-sided one-polepair transversal-flux switched-reluctance-linear-motor prototype is demonstrated and its static properties are measured. The modelling of the static properties is performed with FEM-calculations. Two-dimensional models are accurate enough to model the static key features for the basic dimensioning of LSRmotors. Three-dimensional models must be used in order to get the most accurate calculation results of the static traction force production. The developed dimensioning and modelling methods, which could be systematically validated by laboratory measurements, are the most significant contributions of this thesis. (orig.)

  19. 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.

  20. Devolatilization of wood and wastes in fluidized bed

    Energy Technology Data Exchange (ETDEWEB)

    Gomez-Barea, Alberto; Nilsson, Susanna; Vidal Barrero, Fernando; Campoy, Manuel

    2010-11-15

    Experiments were carried out in a laboratory fluidized bed (FB) to characterize the devolatilization behavior of wood and various wastes at temperatures applicable to FB gasification and combustion, i.e. 750-900 C. The fuels tested were pellets made of wood, meat and bone meal, and compost (from municipal solid wastes), as well as dried granulates of sewage sludge (DSS). Determination of yields of char, condensate and light gas, as well as the composition of the gas and the time of devolatilization during the pyrolysis of single fuel batches was made. A simple model was developed to analyze the mode of conversion of a single wood pellet and DSS granulate, giving insight on the controlling mechanisms during devolatilization. The devolatilization kinetics of DSS was determined by tests using fine granulates. The model was successfully applied to simulate the conversion of large DSS granulates and wood pellets under the whole range of temperatures analyzed. (author)

  1. Modified π π amplitude with σ pole

    Science.gov (United States)

    Bydžovský, P.; Kamiński, R.; Nazari, V.

    2014-12-01

    A set of well-known once subtracted dispersion relations with imposed crossing symmetry condition is used to modify unitary multichannel S (π π , K K ¯, and η η ) and P (π π , ρ 2 π , and ρ σ ) wave amplitudes mostly below 1 GeV. Before the modifications, these amplitudes significantly did not satisfy the crossing symmetry condition and did not describe the π π threshold region. Moreover, the pole of the S wave amplitude related with the f0(500 ) meson (former f0(600 ) or σ ) had much smaller imaginary part and bigger real one in comparison with those in the newest Particle Data Group Tables. Here, these amplitudes are supplemented by near threshold expansion polynomials and refitted to the experimental data in the effective two pion mass from the threshold to 1.8 GeV and to the dispersion relations up to 1.1 GeV. In result the self consistent, i.e., unitary and fulfilling the crossing symmetry condition, S and P wave amplitudes are formed and the σ pole becomes much narrower and lighter. To eliminate doubts about the uniqueness of the so obtained sigma pole position short and purely mathematical proof of the uniqueness of the results is also presented. This analysis is addressed to a wide group of physicists and aims at providing a very effective and easy method of modification of, many presently used, π π amplitudes with a heavy and broad σ meson without changing of their original mathematical structure.

  2. Design Wood Nanocomposites from Polymer Nanocomposites

    Institute of Scientific and Technical Information of China (English)

    LVWenhua; ZHAOGuangjie

    2004-01-01

    Researches on wood nanocomposites, which involve nano science and technology, wood science,materials science and other related subjects, have important science signification and promising prospect for the development and study of new wood composites with high appending values and multi-properties. This paper reviewed the conventional wood composites, and then discussed the approaches to prepare wood nanocomposites. Based on the achievements of researches on polymer/montmorillonite (MMT) nanocomposites, the design ideas of preparing nanocomposites of wood and inorganic MMT were systematically put forward. Nano compounding of wood and other materials is an effective approach to greatly improve or modify wood.

  3. Fast Curing of Composite Wood Products

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Arthur J. Ragauskas

    2006-04-26

    The overall objective of this program is to develop low temperature curing technologies for UF and PF resins. This will be accomplished by: • Identifying the rate limiting UF and PF curing reactions for current market resins; • Developing new catalysts to accelerate curing reactions at reduced press temperatures and times. In summary, these new curing technologies will improve the strength properties of the composite wood products and minimize the detrimental effects of wood extractives on the final product while significantly reducing energy costs for wood composites. This study is related to the accelerated curing of resins for wood composites such as medium density fiberboard (MDF), particle board (PB) and oriented strandboard (OSB). The latter is frequently manufactured with a phenol-formaldehyde resin whereas ureaformaldehyde (UF) resins are usually used in for the former two grades of composite wood products. One of the reasons that hinder wider use of these resins in the manufacturing of wood composites is the slow curing speed as well as inferior bondability of UF resin. The fast curing of UP and PF resins has been identified as an attractive process development that would allow wood to be bonded at higher moisture contents and at lower press temperatures that currently employed. Several differing additives have been developed to enhance cure rates of PF resins including the use of organic esters, lactones and organic carbonates. A model compound study by Conner, Lorenz and Hirth (2002) employed 2- and 4-hydroxymethylphenol with organic esters to examine the chemical basis for the reported enhanced reactivity. Their studies suggested that the enhance curing in the presence of esters could be due to enhanced quinone methide formation or enhanced intermolecular SN2 reactions. In either case the esters do not function as true catalysts as they are consumed in the reaction and were not found to be incorporated in the polymerized resin product. An

  4. Wood energy fuel cycle optimization in beech and spruce forests

    Science.gov (United States)

    Meyer, Nickolas K.; Mina, Marco

    2012-03-01

    A novel synergistic approach to reducing emissions from residential wood combustion (RWC) is presented. Wood energy fuel cycle optimization (FCO) aims to provide cleaner burning fuels through optimization of forestry and renewable energy management practices. In this work, beech and spruce forests of average and high quality were modelled and analysed to determine the volume of fuel wood and its associated bark fraction produced during typical forestry cycles. Two separate fuel wood bark production regimes were observed for beech trees, while only one production regime was observed for spruce. The single tree and stand models were combined with existing thinning parameters to replicate existing management practices. Utilizing estimates of initial seedling numbers and existing thinning patterns a dynamic model was formed that responded to changes in thinning practices. By varying the thinning parameters, this model enabled optimization of the forestry practices for the reduction of bark impurities in the fuel wood supply chain. Beech forestry cycles responded well to fuel cycle optimization with volume reductions of bark from fuel wood of between ˜10% and ˜20% for average and high quality forest stands. Spruce, on the other hand, was fairly insensitive to FCO with bark reductions of 0-5%. The responsiveness of beech to FCO further supports its status as the preferred RWC fuel in Switzerland. FCO could easily be extended beyond Switzerland and applied across continental Europe and North America.

  5. Perturbing rational harmonic functions by poles

    CERN Document Server

    Sète, Olivier; Liesen, Jörg

    2014-01-01

    We study how adding certain poles to rational harmonic functions of the form $R(z)-\\bar{z}$, with $R(z)$ rational and of degree $d\\geq 2$, affects the number of zeros of the resulting functions. Our results are motivated by and generalize a construction of Rhie derived in the context of gravitational microlensing (ArXiv e-print 2003). Of particular interest is the construction and the behavior of rational functions $R(z)$ that are {\\em extremal} in the sense that $R(z)-\\bar{z}$ has the maximal possible number of $5(d-1)$ zeros.

  6. Gauge invariance, causality and gluonic poles

    Energy Technology Data Exchange (ETDEWEB)

    Anikin, I.V., E-mail: anikin@theor.jinr.r [Bogoliubov Laboratory of Theoretical Physics, JINR, 141980 Dubna (Russian Federation); Teryaev, O.V., E-mail: teryaev@theor.jinr.r [Bogoliubov Laboratory of Theoretical Physics, JINR, 141980 Dubna (Russian Federation)

    2010-07-05

    We explore the electromagnetic gauge invariance of the hadron tensor of the Drell-Yan process with one transversely polarized hadron. The special role is played by the contour gauge for gluon fields. The prescription for the gluonic pole in the twist 3 correlator is related to causality property and compared with the prescriptions for exclusive hard processes. As a result we get the extra contributions, which naively do not have an imaginary phase. The single spin asymmetry for the Drell-Yan process is accordingly enhanced by the factor of two.

  7. Wood gas; Holz gibt Gas

    Energy Technology Data Exchange (ETDEWEB)

    Hilgers, Claudia

    2011-06-17

    Sixty years ago, wood gas was even used as a car fuel. Today, this ancient technology is experiencing a renaissance. Small cogeneration plants with wood gasifiers are ideal for renewable and decentral power supply concepts for tomorrow. Until then, there is much pioneering work to do until plants will be ready for serial production.

  8. IMPROVEMENT OF INTERNATIONAL WOOD TRANSPORTATION

    Directory of Open Access Journals (Sweden)

    Sokolov A. P.

    2014-10-01

    Full Text Available The article gives an example of usage of the tool for round-wood transport planning from the Decision Support System “Forest Logistic Toolset” for com-pare of two approaches to the organization of international wood transportation

  9. Assessing potential sustainable wood yield

    Science.gov (United States)

    Robert F. Powers

    2001-01-01

    Society is making unprecedented demands on world forests to produce and sustain many values. Chief among them is wood supply, and concerns are rising globally about the ability of forests to meet increasing needs. Assessing this is not easy. It requires a basic understanding of the principles governing forest productivity: how wood yield varies with tree and stand...

  10. Composites from wood and plastics

    Science.gov (United States)

    Craig Clemons

    2010-01-01

    Composites made from thermoplastics and fillers or reinforcements derived from wood or other natural fibers are a dynamic research area encompassing a wide variety of composite materials. For example, as the use of biopolymers grows, wood and other natural fiber sources are being investigated as renewable sources of fillers and reinforcements to modify performance....

  11. Preservation of forest wood chips

    Energy Technology Data Exchange (ETDEWEB)

    Kofman, P.D.; Thomsen, I.M.; Ohlsson, C.; Leer, E.; Ravn Schmidt, E.; Soerensen, M.; Knudsen, P.

    1999-01-01

    As part of the Danish Energy Research Programme on biomass utilisation for energy production (EFP), this project concerns problems connected to the handling and storing of wood chips. In this project, the possibility of preserving wood chips of the Norway Spruce (Picea Abies) is addressed, and the potential improvements by anaerobic storage are tested. Preservation of wood chips aims at reducing dry matter losses from extensive heating during storage and to reduce production of fungal spores. Fungal spores pose a health hazards to workers handling the chips. Further the producers of wood chips are interested in such a method since it would enable them to give a guarantee for the delivery of homogeneous wood chips also during the winter period. Three different types of wood chips were stored airtight and further one of these was stored in accordance with normal practise and use as reference. The results showed that airtight storage had a beneficial impact on the quality of the chips: no redistribution of moisture, low dry matter losses, unfavourable conditions for microbial activity of most fungi, and the promotion of yeasts instead of fungi with airborne spores. Likewise the firing tests showed that no combustion problems, and no increased risk to the environment or to the health of staff is caused by anaerobic storage of wood chips. In all, the tests of the anaerobic storage method of forest wood chips were a success and a large-scale test of the method will be carried out in 1999. (au)

  12. Moisture transport in coated wood

    NARCIS (Netherlands)

    Meel, P.A. van; Erich, S.J.F.; Huinink, H.P.; Kopinga, K.; Jong, J. DE; Adan, O.C.G.

    2011-01-01

    Moisture accumulation inside wood causes favorable conditions for decay. Application of a coating alters the moisture sorption of wood and prevents accumulation of moisture. This paper presents the results of a nuclear magnetic resonance (NMR) study on the influence of a coating on the moisture abso

  13. Recent advances quantifying the large wood dynamics in river basins: New methods and remaining challenges

    Science.gov (United States)

    Ruiz-Villanueva, Virginia; Piégay, Hervé; Gurnell, Angela A.; Marston, Richard A.; Stoffel, Markus

    2016-09-01

    Large wood is an important physical component of woodland rivers and significantly influences river morphology. It is also a key component of stream ecosystems. However, large wood is also a source of risk for human activities as it may damage infrastructure, block river channels, and induce flooding. Therefore, the analysis and quantification of large wood and its mobility are crucial for understanding and managing wood in rivers. As the amount of large-wood-related studies by researchers, river managers, and stakeholders increases, documentation of commonly used and newly available techniques and their effectiveness has also become increasingly relevant as well. Important data and knowledge have been obtained from the application of very different approaches and have generated a significant body of valuable information representative of different environments. This review brings a comprehensive qualitative and quantitative summary of recent advances regarding the different processes involved in large wood dynamics in fluvial systems including wood budgeting and wood mechanics. First, some key definitions and concepts are introduced. Second, advances in quantifying large wood dynamics are reviewed; in particular, how measurements and modeling can be combined to integrate our understanding of how large wood moves through and is retained within river systems. Throughout, we present a quantitative and integrated meta-analysis compiled from different studies and geographical regions. Finally, we conclude by highlighting areas of particular research importance and their likely future trajectories, and we consider a particularly underresearched area so as to stress the future challenges for large wood research.

  14. The 1500m South Pole Ice Core: Recovering a 40 Ka Environmental Record

    Science.gov (United States)

    Casey, Kimberly Ann; Neumann, Thomas Allen; Fudge, T. J.; Neumann, T. A.; Steig, E. J.; Cavitte, M. G. P.; Blankenship, D. D.

    2014-01-01

    Supported by the US National Science Foundation, a new 1500 m, approximately 40 ka old ice core will be recovered from South Pole during the 2014/15 and 2015/16 austral summer seasons using the new US Intermediate Depth Drill. The combination of low temperatures, relatively high accumulation rates and low impurity concentrations at South Pole will yield detailed records of ice chemistry and trace atmospheric gases. The South Pole ice core will provide a climate history record of a unique area of the East Antarctic plateau that is partly influenced by weather systems that cross the West Antarctic ice sheet. The ice at South Pole flows at approximately 10m a(exp-1) and the South Pole ice-core site is a significant distance from an ice divide. Therefore, ice recovered at depth originated progressively farther upstream of the coring site. New ground-penetrating radar collected over the drill site location shows no anthropogenic influence over the past approximately 50 years or upper 15 m. Depth-age scale modeling results show consistent and plausible annual-layer thicknesses and accumulation rate histories, indicating that no significant stratigraphic disturbances exist in the upper 1500m near the ice-core drill site.

  15. Bridging the gaps: An overview of wood across time and space in diverse rivers

    Science.gov (United States)

    Wohl, Ellen

    2017-02-01

    Nearly 50 years of research focused on large wood (LW) in rivers provide a basis for understanding how wood enters rivers; how wood decays, breaks, and is transported downstream; and how at least temporarily stable wood influences channel geometry, fluxes of water, sediment, and organic matter, and the abundance and diversity of aquatic and riparian organisms. Field-based studies have led to qualitative conceptual models and to numerical stimulations of river processes involving wood. Numerous important gaps remain, however, in our understanding of wood dynamics. The majority of research on wood in rivers focuses on small- to medium-sized rivers, defined using the ratio of wood piece size to channel width as channels narrower than the locally typical wood-piece length (small) and slightly narrower than the longer wood pieces present (medium). Although diverse geographic regions and biomes are represented by one or a few studies in each region, the majority of research comes from perennial rivers draining temperate conifer forests. Regional syntheses most commonly focus on the Pacific Northwest region of North America where most of these studies originate. Consequently, significant gaps in our understanding include lack of knowledge of wood-related processes in large rivers, dryland rivers, and rivers of the high and low latitudes. Using a wood budget as an organizing framework, this paper identifies other gaps related to wood recruitment, transport, storage, and how beavers influence LW dynamics. With respect to wood recruitment, we lack information on the relative importance of mass tree mortality and transport of buried or surficial downed wood from the floodplain into the channel in diverse settings. Knowledge gaps related to wood transport include transport distances of LW and thresholds for LW mobility in small to medium rivers. With respect to wood storage, we have limited data on longitudinal trends in LW loads within unaltered large and great rivers and on

  16. [Biological effect of wood dust].

    Science.gov (United States)

    Maciejewska, A; Wojtczak, J; Bielichowska-Cybula, G; Domańska, A; Dutkiewicz, J; Mołocznik, A

    1993-01-01

    The biological effect of exposure to wood dust depends on its composition and the content of microorganisms which are an inherent element of the dust. The irritant and allergic effects of wood dust have been recognised for a long time. The allergic effect is caused by the wood dust of subtropical trees, e.g. western red cedar (Thuja plicata), redwood (Sequoia sempervirens), obeche (Triplochiton scleroxylon), cocabolla (Dalbergia retusa) and others. Trees growing in the European climate such as: larch (Larix), walnut (Juglans regia), oak (Quercus), beech (Fagus), pine (Pinus) cause a little less pronounced allergic effect. Occupational exposure to irritative or allergic wood dust may lead to bronchial asthma, rhinitis, alveolitis allergica, DDTS (Organic dust toxic syndrome), bronchitis, allergic dermatitis, conjunctivitis. An increased risk of adenocarcinoma of the sinonasal cavity is an important and serious problem associated with occupational exposure to wood dust. Adenocarcinoma constitutes about half of the total number of cancers induced by wood dust. An increased incidence of the squamous cell cancers can also be observed. The highest risk of cancer applies to workers of the furniture industry, particularly those dealing with machine wood processing, cabinet making and carpentry. The cancer of the upper respiratory tract develops after exposure to many kinds of wood dust. However, the wood dust of oak and beech seems to be most carcinogenic. It is assumed that exposure to wood dust can cause an increased incidence of other cancers, especially lung cancer and Hodgkin's disease. The adverse effects of microorganisms, mainly mould fungi and their metabolic products are manifested by alveolitis allergica and ODTS. These microorganisms can induce aspergillomycosis, bronchial asthma, rhinitis and allergic dermatitis.

  17. On the pole content of coupled channels chiral approaches used for the $\\bar{K}N$ system

    CERN Document Server

    Cieplý, A; Meißner, Ulf-G; Smejkal, J

    2016-01-01

    Several theoretical groups describe the antikaon-nucleon interaction at low energies within approaches based on the chiral SU(3) dynamics and including next-to-leading order contributions. We present a comparative analysis of the pertinent models and discuss in detail their pole contents. It is demonstrated that the approaches lead to very different predictions for the $K^{-}p$ amplitude extrapolated to subthreshold energies as well as for the $K^{-}n$ amplitude. The origin of the poles generated by the models is traced to the so-called zero coupling limit, in which the inter-channel couplings are switched off. This provides new insights into the pole contents of the various approaches. In particular, different concepts of forming the $\\Lambda(1405)$ resonance are revealed and constraints related to the appearance of such poles in a given approach are discussed.

  18. Pole-placement self-tuning control of nonlinear Hammerstein system and its application to pH process control

    Institute of Scientific and Technical Information of China (English)

    Zhiyun Zou; Dandan Zhao; Xinghong Liu; Yuqing Guo; Chen Guan; Wenqiang Feng; Ning Guo

    2015-01-01

    By taking advantage of the separation characteristics of nonlinear gain and dynamic sector inside a Hammerstein model, a novel pole placement self tuning control scheme for nonlinear Hammerstein system was put forward based on the linear system pole placement self tuning control algorithm. And the nonlinear Hammerstein system pole placement self tuning control (NL-PP-STC) algorithm was presented in detail. The identification ability of its parameter estimation algorithm of NL-PP-STC was analyzed, which was always identifiable in closed loop. Two particular problems including the selection of poles and the on-line estimation of model parameters, which may be met in applications of NL-PP-STC to real process control, were discussed. The control simulation of a strong nonlinear pH neutralization process was carried out and good control performance was achieved.

  19. Helioseismology from the South Pole: 1987 campaign

    Energy Technology Data Exchange (ETDEWEB)

    Jefferies, S.; Pomerantz, M.A. (Univ. of Delaware, Newark (USA)); Duvall, T.L. Jr. (Goddard Space Flight Center, Greenbelt, MD (USA)); Harvey, J.W.; Jaksha, D. (National Solar Observatory, Tucson, AZ (USA))

    1988-01-01

    Helioseismology is the study of the Sun's interior by means of observations of its global oscillations. The Sun constantly oscillates, at periods of about 5 minutes, in millions of different modes which probe different depth and latitude ranges. Helioseismological observations have been made from the Amundsen-Scott South Pole Station nearly every year since 1980. This site offers the unique advantage of uninterrupted sunlight during the austral summer (except for clouds, of course) and otherwise generally good atmospheric conditions for astronomical observations. Thus, it is possible to measure oscillations without long nighttime gaps which confuse measurements made at low-latitude observatories. Measurements from the South Pole and elsewhere have shown that the solar interior is roughly similar to the predictions of the theory of stellar structure and evolution. This theory is one of the key foundations of our present picture of the universe. It is, therefore, disturbing that there are small, but highly significant, discrepancies between theory and observations and that these discrepancies have not been resolved by reasonable adjustments of theoretical parameters and physics. Currently, the source of these discrepancies is not at all clear. Helioseismology, however, not only revealed the problem but offers excellent prospects for solving it.

  20. Utilizing wood wastes as reinforcement in wood cement composite bricks

    Directory of Open Access Journals (Sweden)

    Nusirat Aderinsola Sadiku

    2015-07-01

    Full Text Available This paper presents the research work undertaken to study the properties of Wood Cement Composite Bricks (WCCB from different wood wastes and cement / wood content. The WCBBs with nominal density of 1200 kg m-3 were produced from three tropical wood species and at varying cement and wood content of 2:1, 2.5:1 and 3:1 on a weight to weight basis. The properties evaluated were compressive strength, Ultra Pulse Velocity (UPV, water absorption (WA and thickness swelling (TS. The Compressive strength values ranged from 0.25 to 1.13 N mm-2 and UPV values ranged from 18753 to 49992 m s-1. The mean values of WA after 672 hours (28 days of water soaking of the WCCBs ranged from 9.50% to 47.13% where there were no noticeable change in the TS of the bricks. The observed density (OD ranged from 627 to 1159 kg m-3. A. zygia from the three wood/cement content were more dimensionally stable and better in compressive strength than the other two species where T. scleroxylon had the best performance in terms of UPV. All the properties improved with increasing cement content. WCCBs at 3.0:1 cement/wood content are suitable for structural application such as panelling, ceiling and partitioning

  1. Development of wood fuel delivery logistics; Puupolttoaineiden hankintalogistiikan kehittaeminen

    Energy Technology Data Exchange (ETDEWEB)

    Laitinen, H.

    1996-12-31

    The main aim of the project is to model the energy wood business and total logistics in a certain large region. First, wood utilisation locations inside this area are examined; the most important ones are the wood processing factories, and the heating- and power plants. After that, wood potentials in the forests of the area are evaluated in sub-areas suitable in size and sufficiently detailed for further evaluations. For that purpose, the most valuable source data are forest management plans, up to ten years forward, on which basis the wood fuel potentials can be evaluated following sustainable development. In Finland there are extensive and detailed data bases storing forest information and it is possible to collect necessary data for a data base applicable to our calculations. In logistical sense it is important to know, by which delivery chains the economically best and desired results are achieved. The software prototype based on data base is modelled and developed at VTT Energy, for facilitating these planning activities. The starting point of the planning system in delivery logistics is the implementation of an easy tool for versatile planning so that with this tool model different delivery chains can be flexiblyed, create usage scenarios, make alternative examinations, and calculate impacts of different factors on energy wood amounts yielded and delivery costs. With planning system in delivery logistics we calculate production costs and amounts delivered to different utilisation locations. The system offers tools for definitions of utilisation locations, calculation parameters, and delivery chains

  2. Generalized theory of mixed pole machines with a general rotor configuration

    Directory of Open Access Journals (Sweden)

    Ayman S. Abdel-khalik

    2013-03-01

    Full Text Available This paper introduces a generalized theory for the operation of mixed pole machines (MPMs. The MPM has two stator windings, namely the main winding with pole pairs P1 and the control winding with pole pairs P2. The MPM has shown promise in the field of adjustable speed drives for large machines and in the field of wind energy electrical generation. The operation of MPM relies on the interaction between the two fields produced by the two stator windings through the intermediate action of a specially designed rotor (nested-cage or reluctance rotor. The machine theory is described from a physical aspect rather than mathematical derivations. A simple representation is also presented, from which the machine d–q model can be readily deduced. The effect of mechanical loading on the relative positions of the machine fields is also presented.

  3. Comparison of higher harmonic contents in salient pole synchronous generator with different rotor construction

    Directory of Open Access Journals (Sweden)

    Ludwinek Krzysztof

    2017-03-01

    Full Text Available The paper presents a comparison of higher harmonics in induced phase voltages of a stator winding in the no-load state of a three-phase 5.5 kVA salient pole synchronous generator. The comparison is carried out for the synchronous generator with different salient pole rotor constructions: a non-skewed solid rotor, a non-skewed solid rotor with radial incisions, and a laminated electrotechnical steel rotor with skewed slots and damping bars. The calculations of higher harmonics are based on the magnetic field distributions in the air gap, which are carried out in a 2D model in a FEMM program and on the induced voltage waveforms in the stator windings registered during experimental investigations of the 5.5 kVA salient pole synchronous generator in the no-load state.

  4. Experimental Identification and Vibration Control of A Piezoelectric Flexible Manipulator Using Optimal Multi-Poles Placement Control

    Directory of Open Access Journals (Sweden)

    Junqiang Lou

    2017-03-01

    Full Text Available This paper presents experimental identification and vibration suppression of a flexible manipulator with piezoelectric actuators and strain sensors using optimal multi-poles placement control. To precisely identify the system model, a reduced order transfer function with relocated zeros is proposed, and a first-order inertia element is added to the model. Comparisons show the identified model match closely with the experimental results both in the time and frequency domains, and a fit of 97.2% is achieved. Based on the identified model, a full-state multi-poles placement controller is designed, and the optimal locations of the closed loop poles are determined where the move distance of the closed loop poles is the shortest. The feasibility of the proposed controller is validated by simulations. Moreover, the controller is tested for different locations of the closed loop poles, and an excellent performance of the optimal locations of the closed loop poles is shown. Finally, the effectiveness of the proposed controller is demonstrated by experiments. Results show that the vibrations of the expected modes are significantly diminished. Accordingly, multi-mode vibrations of the manipulator are well attenuated.

  5. Molecular deformation mechanisms of the wood cell wall material.

    Science.gov (United States)

    Jin, Kai; Qin, Zhao; Buehler, Markus J

    2015-02-01

    Wood is a biological material with outstanding mechanical properties resulting from its hierarchical structure across different scales. Although earlier work has shown that the cellular structure of wood is a key factor that renders it excellent mechanical properties at light weight, the mechanical properties of the wood cell wall material itself still needs to be understood comprehensively. The wood cell wall material features a fiber reinforced composite structure, where cellulose fibrils act as stiff fibers, and hemicellulose and lignin molecules act as soft matrix. The angle between the fiber direction and the loading direction has been found to be the key factor controlling the mechanical properties. However, how the interactions between theses constitutive molecules contribute to the overall properties is still unclear, although the shearing between fibers has been proposed as a primary deformation mechanism. Here we report a molecular model of the wood cell wall material with atomistic resolution, used to assess the mechanical behavior under shear loading in order to understand the deformation mechanisms at the molecular level. The model includes an explicit description of cellulose crystals, hemicellulose, as well as lignin molecules arranged in a layered nanocomposite. The results obtained using this model show that the wood cell wall material under shear loading deforms in an elastic and then plastic manner. The plastic regime can be divided into two parts according to the different deformation mechanisms: yielding of the matrix and sliding of matrix along the cellulose surface. Our molecular dynamics study provides insights of the mechanical behavior of wood cell wall material at the molecular level, and paves a way for the multi-scale understanding of the mechanical properties of wood.

  6. Modelling water fluxes in a pine wood soil-vegetation-atmosphere system. Comparison of a water budget and water flow model using different parameter data sources

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, S.; Jacques, D.; Mallants, D.

    2010-02-15

    For modelling complex hydrological problems, realistic models and accurate hydraulic properties are needed. A mechanistic model (HYDRUS-1D) and a compartment model are evaluated for simulating the water balance in a soil-vegetation-atmosphere system using time series of measured water content at several depths in two lysimeters in a podzol soil with Scots Pine vegetation. 10 calibration scenarios are used to investigate the impact of the model type and the number of horizons in the profile on the calibration accuracy. Main results are: (i) with a large number of soil layers, both models describe accurately the water contents at all depths, (II) the number of soil layers is the major factor that controls the quality of the calibration. The compartment model is as an abstracted model and the mechanistic model is our reference model. Drainage values are the considered output. Drainage values simulated by the abstracted model were close to those of the reference model when averaged over a sufficiently long period (about 9 months). This result suggests that drainage values obtained with an abstracted model are reliably when averaged over sufficiently long periods; the abstracted model needs less computational time without an important loss of accuracy.

  7. Nonlinear effect induced in thermally poled glass waveguides

    Institute of Scientific and Technical Information of China (English)

    REN Yi-tao

    2006-01-01

    Thermally poled germanium-doped channel waveguides are presented. Multilayer waveguides containing a silicon oxynitride layer were used as charge trapper in this investigation on the effect of the internal field inside the waveguide. Compared to waveguides without the trapping layer, experimental results showed that the induced linear electro-optic (EO) coefficient increases about 20% after poling, suggesting strongly that the internal field is relatively enhanced, and showed it is a promising means for improving nonlinearity by poling in waveguides.

  8. Least Square Approximation by Linear Combinations of Multi(Poles).

    Science.gov (United States)

    1983-04-01

    ID-R134 069 LEAST SQUARE APPROXIMATION BY LINEAR COMBINATIONS OF i/i MULTI(POLES). 1U OHIO STATE UNIV COLUMBUS DEPT OF GEODETIC SCIENCE AND SURVEY...TR-83-0 117 LEAST SQUARE APPROXIMATION BY LINEAR COMBINATIONS OF (MULTI)POLES WILLI FREEDEN DEPARTMENT OF GEODETIC SCIENCE AND SURVEYING THE OHIO...Subtitle) S. TYPE OF REPORT & PERIOD COVERED LEAST SQUARE APPROXIMATION BY LINEAR Scientific Report No. 3 COMBINATIONS OF (MULTI)POLES 6. PERFORMING ORG

  9. Charge quantisation without magnetic poles: a topological approach to electromagnetism

    OpenAIRE

    Solha, Romero

    2014-01-01

    The present work provides a theoretical explanation for the quantisation of electric charges, an open problem since Millikan's oil drop experiment in 1909. This explanation is based solely on Maxwell's theory, it recasts Electromagnetic theory under the language of complex line bundles; therefore, neither magnetic poles nor quantum mechanics are invoked. The existence of magnetic poles was essentially the only theoretical explanation for charge quantisation (e.g. Dirac's magnetic pole), and t...

  10. PolyPole-1: An accurate numerical algorithm for intra-granular fission gas release

    Energy Technology Data Exchange (ETDEWEB)

    Pizzocri, D.; Rabiti, C.; Luzzi, L.; Barani, T.; Van Uffelen, P.; Pastore, G.

    2016-09-01

    This paper describes the development of a new numerical algorithm (called PolyPole-1) to efficiently solve the equation for intra-granular fission gas release in nuclear fuel. The work was carried out in collaboration with Politecnico di Milano and Institute for Transuranium Elements. The PolyPole-1 algorithms is being implemented in INL's fuels code BISON code as part of BISON's fission gas release model. The transport of fission gas from within the fuel grains to the grain boundaries (intra-granular fission gas release) is a fundamental controlling mechanism of fission gas release and gaseous swelling in nuclear fuel. Hence, accurate numerical solution of the corresponding mathematical problem needs to be included in fission gas behaviour models used in fuel performance codes. Under the assumption of equilibrium between trapping and resolution, the process can be described mathematically by a single diffusion equation for the gas atom concentration in a grain. In this work, we propose a new numerical algorithm (PolyPole-1) to efficiently solve the fission gas diffusion equation in time-varying conditions. The PolyPole-1 algorithm is based on the analytic modal solution of the diffusion equation for constant conditions, with the addition of polynomial corrective terms that embody the information on the deviation from constant conditions. The new algorithm is verified by comparing the results to a finite difference solution over a large number of randomly generated operation histories. Furthermore, comparison to state-of-the-art algorithms used in fuel performance codes demonstrates that the accuracy of the PolyPole-1 solution is superior to other algorithms, with similar computational effort. Finally, the concept of PolyPole-1 may be extended to the solution of the general problem of intra-granular fission gas diffusion during non-equilibrium trapping and resolution, which will be the subject of future work.

  11. Study of consolidating materials applied on wood by hyperspectral imaging

    Science.gov (United States)

    Bonifazi, G.; Serranti, S.; Capobianco, G.; Agresti, G.; Calienno, L.; Picchio, R.; Lo Monaco, A.; Santamaria, U.; Pelosi, C.

    2016-05-01

    The focus of this study was addressed to investigate the potentiality of HyperSpectral Imaging (HSI) in the monitoring of commercial consolidant products applied on wood samples. Poplar (Populus Sp.) and walnut (Juglans Regia L.) were chosen for the consolidant application. Both traditional and innovative products were selected, based on acrylic, epoxy and aliphatic compounds. Wood samples were stresses by freeze/thaw cycles in order to cause material degradation. Then the consolidants were applied under vacuum. The samples were finally artificially aged for 168 hours in a solar box chamber. The samples were acquired in the SWIR (1000-2500 nm) range by SISUChema XL™ device (Specim, Finland) after 168 hours of irradiation. As comparison, color measurement was also used as economic, simple and noninvasive technique to evaluate the deterioration and consolidation effects on wood. All data were then processed adopting a chemometric approach finalized to define correlation models, HSI based, between consolidating materials, wood species and short time ageing effects.

  12. South Pole Region of the Moon as Seen by Clementine

    Science.gov (United States)

    1994-01-01

    Lunar mosaic of 1500 Clementine images of the south polar region of the moon. The projection is orthographic, centered on the south pole. The Schrodinger Basin (320 km in diameter) is located in the lower right of the mosaic. Amundsen-Ganswindt is the more subdued circular basin between Schrodinger and the pole. The polar regions of the moon are of special interest because of the postulated occurrence of ice in permanently shadowed areas. The south pole is of greater interest because the area that remains in shadow is much larger than that at the north pole.

  13. Effects of poling process on KNN-modified piezoceramic properties

    OpenAIRE

    Marcos Rubio, F.; Romero, J. J.; Ochoa Guerrero, Diego A.; García García, José Eduardo; Pérez Pérez, Rafael; Fernández, José Francisco

    2010-01-01

    The influence of the orthorhombic to tetragonal phase transition near room temperature in the poling process of KNN-modified piezoceramics was studied. Poling temperatures of 25° and 120°C were used. The percentage of 90° domains reorientation induced by poling was evaluated trough X-ray diffraction analysis. The improvement of the piezoelectric properties when the poling temperature was 25°C could not be explained by the reorientation of 90° domains alone. Raman spectroscopy evidenced that t...

  14. Lunar Pole Illumination and Communications Maps Computed from GSSR Elevation Data

    Science.gov (United States)

    Bryant, Scott

    2009-01-01

    A Digital Elevation Model of the lunar south pole was produced using Goldstone Solar System RADAR (GSSR) data obtained in 2006.12 This model has 40-meter horizontal resolution and about 5-meter relative vertical accuracy. This Digital Elevation Model was used to compute average solar illumination and Earth visibility with 100 kilometers of the lunar south pole. The elevation data were converted into local terrain horizon masks, then converted into lunar-centric latitude and longitude coordinates. The horizon masks were compared to latitude, longitude regions bounding the maximum Sun and Earth motions relative to the moon. Estimates of Earth visibility were computed by integrating the area of the region bounding the Earth's motion that was below the horizon mask. Solar illumination and other metrics were computed similarly. Proposed lunar south pole base sites were examined in detail, with the best site showing yearly solar power availability of 92 percent and Direct-To-Earth (DTE) communication availability of about 50 percent. Similar analysis of the lunar south pole used an older GSSR Digital Elevation Model with 600-meter horizontal resolution. The paper also explores using a heliostat to reduce the photovoltaic power system mass and complexity.

  15. Lunar Pole Illumination and Communications Maps Computed from GSSR Elevation Data

    Science.gov (United States)

    Bryant, Scott

    2009-01-01

    A Digital Elevation Model of the lunar south pole was produced using Goldstone Solar System RADAR (GSSR) data obtained in 2006.12 This model has 40-meter horizontal resolution and about 5-meter relative vertical accuracy. This Digital Elevation Model was used to compute average solar illumination and Earth visibility with 100 kilometers of the lunar south pole. The elevation data were converted into local terrain horizon masks, then converted into lunar-centric latitude and longitude coordinates. The horizon masks were compared to latitude, longitude regions bounding the maximum Sun and Earth motions relative to the moon. Estimates of Earth visibility were computed by integrating the area of the region bounding the Earth's motion that was below the horizon mask. Solar illumination and other metrics were computed similarly. Proposed lunar south pole base sites were examined in detail, with the best site showing yearly solar power availability of 92 percent and Direct-To-Earth (DTE) communication availability of about 50 percent. Similar analysis of the lunar south pole used an older GSSR Digital Elevation Model with 600-meter horizontal resolution. The paper also explores using a heliostat to reduce the photovoltaic power system mass and complexity.

  16. Non_standard Wood

    DEFF Research Database (Denmark)

    Tamke, Martin

    Non-Standard elements in architecture bear the promise of a better more specific performance (Oosterhuis 2003). A new understanding of design evolves, which is focusing on open ended approaches, able to negotiate between shifting requirements and to integrate knowledge on process and material......- and machine industry we fabricated a 1:1 demonstrator show casing the potential for performance due to digital fabrication in this sustainable material. The production of a custom made design tool helped not only to explore design variations while keeping up the link to digital production machinery....... 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...

  17. Cooling of wood briquettes

    Directory of Open Access Journals (Sweden)

    Adžić Miroljub M.

    2013-01-01

    Full Text Available This paper is concerned with the experimental research of surface temperature of wood briquettes during cooling phase along the cooling line. The cooling phase is an important part of the briquette production technology. It should be performed with care, otherwise the quality of briquettes could deteriorate and possible changes of combustion characteristics of briquettes could happen. The briquette surface temperature was measured with an IR camera and a surface temperature probe at 42 sections. It was found that the temperature of briquette surface dropped from 68 to 34°C after 7 minutes spent at the cooling line. The temperature at the center of briquette, during the 6 hour storage, decreased to 38°C.

  18. 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....

  19. Bioprocessing preservative-treated waste wood

    Science.gov (United States)

    Barbara L. Illman; Vina W. Yang; Les. Ferge

    2000-01-01

    Disposal of preservative-treated waste wood is a growing problem worldwide. Bioprocessing the treated wood offers one approach to waste management under certain conditions. One goal is to use wood decay fungi to reduce the volume of waste with an easily managed system in a cost-effective manner. Wood decay fungi were obtained from culture collections in the Mycology...

  20. Wood Technology: Techniques, Processes, and Products

    Science.gov (United States)

    Oatman, Olan

    1975-01-01

    Seven areas of wood technology illustrates applicable techniques, processes, and products for an industrial arts woodworking curriculum. They are: wood lamination; PEG (polyethylene glycol) diffusion processes; wood flour and/or particle molding; production product of industry; WPC (wood-plastic-composition) process; residential construction; and…

  1. FIRE INSURANCE AND WOOD SCHOOL BUILDINGS.

    Science.gov (United States)

    PURCELL, FRANK X.

    A COMPARISON OF FIRE INSURANCE COSTS OF WOOD, MASONRY, STEEL AND CONCRETE STRUCTURES SHOWS FIRE INSURANCE PREMIMUMS ON WOOD STRUCTURES TEND TO BE HIGHER THAN PREMIUMS ON MASONRY, STEEL AND CONCRETE BUILDINGS, HOWEVER, THE INITIAL COST OF THE WOOD BUILDINGS IS LOWER. DATA SHOW THAT THE SAVINGS ACHIEVED IN THE INITIAL COST OF WOOD STRUCTURES OFFSET…

  2. 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 phy

  3. RHEOLOGICAL BEHAVIOR OF WOOD AND WOOD BASED MATERIALS

    Directory of Open Access Journals (Sweden)

    Rafael Rodolfo de Melo

    2010-05-01

    Full Text Available The wood, as well as other construction materials, presents changes in this stiffness and strength when submitted to a long time loading. This phenomenon is important in the analyses resistance capacity of structural materials. Mechanically, the wood behaves as aviscous-elastic solid. However, over time, the structural elements submitted to permanent or cyclic loading presents some deformation, which denotes a viscous-elastic behavior. This characteristic is influenced mainly on the intensity and duration of loading. In this study a review of rheological phenomenon is presented, showing up the causes and effects for a better understanding, which is essential for the appropriate and efficient use of the wood and wood composites as structural materials.

  4. COMBUSTION PROPERTIES OF EUCALYPTUS WOOD

    Directory of Open Access Journals (Sweden)

    Yalçın ÖRS

    1999-03-01

    Full Text Available In this study, the combustion properties of some impregnation materials (abiotic and biotic factors used for eucalyptus wood in interior or exterior environments were investigated. The experimental samples were prepared from Eucalyptus wood based on ASTM-D-1413-76 Tanalith-CBC, boric acid, borax, vacsol-WR, immersol-WR, polyethylen glycole-400 and ammonium sulphate were used as an impregnation material. The results indicated that, vacuum treatment on Eucalyptus gave the lowest retention value of salts. Compounds containing boron+salt increased fire resistance however water repellents decreased the wood flammability.

  5. A CONTINUING REVERENCE FOR WOOD

    Directory of Open Access Journals (Sweden)

    Martin A. Hubbe

    2010-02-01

    Full Text Available Our ancestors knew a great deal about wood. They had to in order to do well in life. Wood has played a dominant role in human infrastructure for many generations, and for most of that time woodcraft has depended on the decentralized knowledge passed down among families and guilds. This editorial, while celebrating the knowledge, skills, and insights of the woodworkers of past generations, also calls for a renewed attention to wood’s unique character, including characteristics that today are too often classified as “defects.” We may need to take lessons from generations past to truly derive the best value from wood resources.

  6. ELASTIC CHARACTERIZATION OF Eucalyptus citriodora WOOD

    Directory of Open Access Journals (Sweden)

    Adriano Wagner Ballarin

    2003-01-01

    Full Text Available This paper contributed to the elastic characterization of Eucalyptus citriodora grown inBrazil, considering an orthotropic model and evaluating its most important elastic constants.Considering this as a reference work to establish basic elastic ratios — several important elasticconstants of Brazilian woods were not determined yet - the experimental set-up utilized one tree of 65years old from plantations of “Horto Florestal Navarro de Andrade”, at Rio Claro-SP, Brazil. All theexperimental procedures attended NBR 7190/97 – Brazilian Code for wooden structures –withconventional tension and compression tests. Results showed statistical identity between compressionand tension modulus of elasticity. The relation observed between longitudinal and radial modulus ofelasticity was 10 (EL/ER ≈ 10 and same relation, considering shear modulus (modulus of rigidity was20 (EL/GLR ≈ 20. These results, associated with Poisson’s ratios herein determined, allow theoreticalmodeling of wood mechanical behavior in structures.

  7. Remarks on the Woods-Saxon Potential

    CERN Document Server

    Capak, M

    2016-01-01

    More recently, comprehensive application results of approximate analytical solutions of the Woods-Saxon potential in closed form for the 5-dimensional Bohr Hamiltonian have been appeared [14] and its comparison to the data for many different nuclei has clearly revealed the domains for the sucsess and failure in case of using such potential forms to analyse the data concerning with the nuclear structure of deformed nuclei within the frame of the collective model. Gaining confidence from this work, exact solvability of the Woods-Saxon type potentials in lower dimensions for the bound states having zero angular momentum is carefully reviewed to finalize an ongoing discussion in the related literature and clearly shown that such kind of potentials have no analytical solutions even for l=0 case.

  8. Mathematical Models and Analysis of Particle Size of Coniferous Wood Flour Based on the Least Squares Method%基于最小二乘法的落叶松木粉粒径数学建模与分析

    Institute of Scientific and Technical Information of China (English)

    任洪娥; 沈雯雯; 白杰云; 官俊

    2015-01-01

    Objective]This paper established a mathematical model of the particle size of larch wood floor,and obtained optimum particle size of wood flour that corresponding to the maximum aspect ratio of wood flour and revealed the change trend of the aspect ratio as the particle size of wood flour decreases and explained the reasons for this trend by analysing the mathematical model and the second order derivative.[Method]We take the microscopic image of wood floor with the optical microscope,and obtain the average length and average width of mature tracheids and the particle size of target wood floor by the measurement and calculation. With the digital image processing technology,we extract the length, width and rectangular of each single wood flour: we convert the color space of original wood flour microscopic image from RGB to Lab and then extract the b component; And the b component is filtered by 3 × 3 template median filter. To get the binary image of wood flour,we cluster the denoised image into 2 categories with the K-means algorithm. The binary images are executed by the first opening after closing operations of mathematical morphology with 5 × 5 structure elements. Then we mark each single wood flour by eight connected region labeling method. After that ,we calculate the geometric area of wood flour by the method of the number of target pixels in statistics and calculate the length,width,area of the minimum bounding rectangle of wood flour by the method of spindle law on the labeled image. At last we get the data of aspect ratio and squareness of each single wood flour. After getting the data above,we create the fitting curve between particle size and aspect ratio with the least squares method,and select the Gaussian function as the mathematical model by analyzing and evaluating the fitting function of polynomial function,Fourier function and Gaussian function,then we calculate the second derivative according to its fitting curve. Finally we analysis and discuss

  9. Pole assignment in descriptor periodic systems

    Institute of Scientific and Technical Information of China (English)

    FAN; Hung-Yuan; LIN; Wen-Wei; XU; Shufang

    2005-01-01

    In this paper a pole assignment problem is considered for the descriptor linear discrete-time periodic systems, which is using the periodic proportional-derivative feedback to modify a given system such that the closed loop system has a specified selfconjugate set of eigenvalues. It is shown that the complete reachability of an open loop periodic system is equivalent to the possibility of assigning an arbitrary set of the eigenvalues to the system by choosing the suitable periodic proportional-derivative feedback.A computational approach is also proposed to solve the problem, which uses the reliable numerical techniques based on the orthogonal transformations. Numerical examples are presented to illustrate the effectiveness of the proposed approach.

  10. Spherical harmonics, invariant theory and Maxwell's poles

    CERN Document Server

    Dowker, J S

    2008-01-01

    I discuss the relation between harmonic polynomials and invariant theory and show that homogeneous, harmonic polynomials correspond to ternary forms that are apolar to a base conic (the absolute). The calculation of Schlesinger that replaces such a form by a polarised binary form is reviewed. It is suggested that Sylvester's theorem on the uniqueness of Maxwell's pole expression for harmonics is renamed the Clebsch-Sylvester theorem. The relation between certain constructs in invariant theory and angular momentum theory is enlarged upon and I resurrect the Joos--Weinberg matrices. Hilbert's projection operators are considered and their generalisations by Story and Elliott are related to similar, more recent constructions in group theory and quantum mechanics, the ternary case being equivalent to SU(3).

  11. VOLUMETRY AND SURVIVAL OF NATIVE AND EXOTIC SPECIES IN THE GYPSUN POLE OF ARARIPE, PE

    Directory of Open Access Journals (Sweden)

    Bruno Coelho de Barros

    2010-12-01

    Full Text Available In the industrial and commercial sectors of the Araripe Region in Pernambuco, Brazil, fire wood is the used in processes of dehydration and production of gypsum with different technologies. Thus, this study aimed to find alternatives to supply the demand of firewood in the Gypsun Pole of Araripe in Pernambuco through the implementation of forest with native and exotic species. The experiment was installed at the Experimental Station of the Agronomic Institute of Pernambuco (IPA, using nine species, both native and exotic: (Imburana - Amburana cearense (Allemão A.C. Sm.; Angico - Anadenanthera colubrina (Vell. Brenan  var. cebil (Griseb. Altschul; Jurema - Mimosa tenuiflora (Willd. Poir.; Sabiá - Mimosa caesalpiniaefolia Benth.; Acácia - Senna siamea (Lam. H.S. Irwin & Barneby; Leucena - Leucaena leucocephala (Lam. R. de Wit.; Algaroba - Prosopis juliflora (Sw. D.C.; Ipês - Tabebuia sp.1 e Tabebuia sp.2. The design was completely randomized with different numbers of replications. The following parameters were evaluated: volume in cubic meter (m³ and stereo meters (st and survival. With regard to the volume in cubic meter, Sabia had the best production. The Jurema and the Sabiá were the heaviest species. In relation to survival, the Ipê 2 and the Imburana had the highest mortalities. Thus, the Sabiá and the Jurema are the species indicated for the production of wood in homogeneous commercial plantations in the Chapada Araripe in Pernambuco.

  12. Plasmon Pole Approximation within the GW Lanczos approach

    Science.gov (United States)

    Gosselin, Vincent; Rousseau, Bruno; Cote, Michel

    2015-03-01

    The well-known DFT gap problem is adressed by computational methods that are more ressource intensive both in terms of memory and time requirements. Amongst other methods, the GW approach has known great success in the field of electronic structure calculations. Addressing the main bottlenecks impeding one shot GW calculations, a sum over all conduction states and an integral over all frequencies must be carried. Within an implementation of the GW method based on the Lanczos algorithm, the sum over conduction states is treated with a Sternheimer method whereas the frequency integral is carried out numerically. In this talk, I will present an implementation of a plasmon-pole model combined with the Lanczos method that allows a treatement of this integral that is computationally favorable.

  13. Special Economic Zones as Growth and Anti-growth Poles as Exemplified by Polish Regions

    Directory of Open Access Journals (Sweden)

    Hanna Godlewska-Majkowska

    2016-12-01

    Full Text Available Objective: The objective of this paper is to present the effects of special economic zones (SEZ on the polarisation of public economic space in Polish regions. Research Design & Methods: The paper looks at both positive and negative effects of economic zones on the polarization of economic space in Polish regions. In an empirical analysis of internal and external effects of SEZs growth centres are identified. Centre of the polarised region, as a source of development incentives, characterised with a higher growth dynamics in comparison to the other part of the region is identified as a growth pole; while the centre of a polarised region being a source of crisis factors higher than in the region is identified as an anti-growth pole. Findings: In the result of conducted studies 8 growth poles, 19 centres of unstable economic situation have been identified, anti-growth poles has not been identified. Factors that result in the polarisation as well as its positive and negative characteristics were identified. Implications & Recommendations: The new model, which captures growing changes and can activate an appropriate action aimed at avoiding crisis can be used as a potential early warning system by the authorities of territorial units. Contribution & Value Added: The originality of this work lies in proposing a new methodological approach to identify poles and anti-poles. This approach can be applied for various tiers of taxonomic division for regions in various countries and forms of public aid.

  14. Wood decay in desert riverine environments

    Science.gov (United States)

    Andersen, Douglas; Stricker, Craig A.; Nelson, S. Mark

    2016-01-01

    Floodplain forests and the woody debris they produce are major components of riverine ecosystems in many arid and semiarid regions (drylands). We monitored breakdown and nitrogen dynamics in wood and bark from a native riparian tree, Fremont cottonwood (Populus deltoides subsp. wislizeni), along four North American desert streams. We placed locally-obtained, fresh, coarse material [disks or cylinders (∼500–2000 cm3)] along two cold-desert and two warm-desert rivers in the Colorado River Basin. Material was placed in both floodplain and aquatic environments, and left in situ for up to 12 years. We tested the hypothesis that breakdown would be fastest in relatively warm and moist aerobic environments by comparing the time required for 50% loss of initial ash-free dry matter (T50) calculated using exponential decay models incorporating a lag term. In cold-desert sites (Green and Yampa rivers, Colorado), disks of wood with bark attached exposed for up to 12 years in locations rarely inundated lost mass at a slower rate (T50 = 34 yr) than in locations inundated during most spring floods (T50 = 12 yr). At the latter locations, bark alone loss mass at a rate initially similar to whole disks (T50 = 13 yr), but which subsequently slowed. In warm-desert sites monitored for 3 years, cylinders of wood with bark removed lost mass very slowly (T50 = 60 yr) at a location never inundated (Bill Williams River, Arizona), whereas decay rate varied among aquatic locations (T50 = 20 yr in Bill Williams River; T50 = 3 yr in Las Vegas Wash, an effluent-dominated stream warmed by treated wastewater inflows). Invertebrates had a minor role in wood breakdown except at in-stream locations in Las Vegas Wash. The presence and form of change in nitrogen content during exposure varied among riverine environments. Our results suggest woody debris breakdown in desert riverine ecosystems is primarily a microbial process with rates determined by landscape position

  15. CMB Observations with the South Pole Telescope

    Science.gov (United States)

    Keisler, Ryan

    2013-04-01

    I will describe a program of cosmological research centered on using measurements of the cosmic microwave background (CMB) to address questions relevant to physics: What is the absolute mass scale of neutrinos? How many species of neutrino-like particles were present in the early Universe? How does gravity behave on cosmological scales? Did inflation occur, and, if so, at what energy scale? A new generation of CMB experiments is targeting these questions, and I will focus on recent results from the South Pole Telescope (SPT). The SPT is a ground-based mm-wave observatory located at the geographic south pole in Antarctica, and in 2011 finished its initial, 2500 square-degree ``SPT-SZ'' survey. The data from this survey provided an unprecedented combination of resolution, area, and sensitivity, and has been used to make ground-breaking measurements of the CMB anisotropy and the gravitational lensing of the CMB. These measurements have, in conjunction with data from the WMAP satellite, led to strong constraints on the number of neutrino-like particle species present in the early universe and the shape of the power spectrum of primordial density fluctuations. The SPT-SZ data overlaps with the ongoing Dark Energy Survey (DES) footprint, and the joint dataset will provide new probes of large-scale structure, such as the relative velocities of massive galaxy clusters. In 2012, a new polarization-sensitive camera, SPTpol, was installed on the SPT, and I will summarize its performance and prospects for detecting the B-mode CMB polarization pattern. Finally, I will touch on what will be possible with a third-generation camera, SPT-3G. The leap in sensitivity provided by this camera will yield, for example, a constraint on the sum of the neutrino masses relevant for exploring the neutrino mass hierarchy.

  16. Swing phase kinematics of horses trotting over poles.

    Science.gov (United States)

    Brown, S; Stubbs, N C; Kaiser, L J; Lavagnino, M; Clayton, H M

    2015-01-01

    Trotting over poles is used therapeutically to restore full ranges of limb joint motion. The mechanics of trotting over poles have not yet been described, hence quantitative evidence for the presumed therapeutic effects is lacking. To compare limb kinematics in horses trotting over level ground, over low poles and over high poles to determine changes in joint angulations and hoof flight arcs. Repeated measures experimental study in sound horses. Standard motion analysis procedures with skin-fixed reflective markers were used to measure swing phase kinematics from 8 horses trotting on level ground, over low (11 cm) and high (20 cm) poles spaced 1.05 ± 0.05 m apart. Spatiotemporal variables and peak swing phase joint flexion angles were compared using repeated measures ANOVA (Plow poles (fore: 30.9 ± 4.9 cm; hind: 24.9 ± 3.7 cm) and to high poles (fore: 41.0 ± 3.9 cm; hind: 32.7 ± 4.0 cm). All joints of the fore- and hindlimbs contributed to the increase in hoof height through increased swing phase flexion. The hooves cleared the poles due to increases in joint flexion rather than by raising the body higher during the suspension phases of the stride. The increases in swing phase joint flexions indicate that trotting over poles is effective for activating and strengthening the flexor musculature. Unlike the use of proprioceptive stimulation devices in which the effects decrease over time due to habituation, the horse is required to elevate the hooves to ensure clearance whenever poles are present. The need to raise the limbs sufficiently to clear the poles and place the hooves accurately requires visuomotor coordination, which may be useful in the rehabilitation of neurological cases. The Summary is available in Chinese - see Supporting information. © 2014 EVJ Ltd.

  17. Automatic measurement of compression wood cell attributes in fluorescence microscopy images.

    Science.gov (United States)

    Selig, B; Luengo Hendriks, C L; Bardage, S; Daniel, G; Borgefors, G

    2012-06-01

    This paper presents a new automated method for analyzing compression wood fibers in fluorescence microscopy. Abnormal wood known as compression wood is present in almost every softwood tree harvested. Compression wood fibers show a different cell wall morphology and chemistry compared to normal wood fibers, and their mechanical and physical characteristics are considered detrimental for both construction wood and pulp and paper purposes. Currently there is the need for improved methodologies for characterization of lignin distribution in wood cell walls, such as from compression wood fibers, that will allow for a better understanding of fiber mechanical properties. Traditionally, analysis of fluorescence microscopy images of fiber cross-sections has been done manually, which is time consuming and subjective. Here, we present an automatic method, using digital image analysis, that detects and delineates softwood fibers in fluorescence microscopy images, dividing them into cell lumen, normal and highly lignified areas. It also quantifies the different areas, as well as measures cell wall thickness. The method is evaluated by comparing the automatic with a manual delineation. While the boundaries between the various fiber wall regions are detected using the automatic method with precision similar to inter and intra expert variability, the position of the boundary between lumen and the cell wall has a systematic shift that can be corrected. Our method allows for transverse structural characterization of compression wood fibers, which may allow for improved understanding of the micro-mechanical modeling of wood and pulp fibers.

  18. Effects of heat treatment of wood on hydroxylapatite type mineral precipitation and biomechanical properties in vitro.

    Science.gov (United States)

    Rekola, J; Lassila, L V J; Hirvonen, J; Lahdenperä, M; Grenman, R; Aho, A J; Vallittu, P K

    2010-08-01

    Wood is a natural fiber reinforced composite. It structurally resembles bone tissue to some extent. Specially heat-treated birch wood has been used as a model material for further development of synthetic fiber reinforced composites (FRC) for medical and dental use. In previous studies it has been shown, that heat treatment has a positive effect on the osteoconductivity of an implanted wood. In this study the effects of two different heat treatment temperatures (140 and 200 degrees C) on wood were studied in vitro. Untreated wood was used as a control material. Heat treatment induced biomechanical changes were studied with flexural and compressive tests on dry birch wood as well as on wood after 63 days of simulated body fluid (SBF) immersion. Dimensional changes, SBF sorption and hydroxylapatite type mineral formation were also assessed. The results showed that SBF immersion decreases the biomechanical performance of wood and that the heat treatment diminishes the effect of SBF immersion on biomechanical properties. With scanning electron microscopy and energy dispersive X-ray analysis it was shown that hydroxylapatite type mineral precipitation formed on the 200 degrees C heat-treated wood. An increased weight gain of the same material during SBF immersion supported this finding. The results of this study give more detailed insight of the biologically relevant changes that heat treatment induces in wood material. Furthermore the findings in this study are in line with previous in vivo studies.

  19. Quantitative Proteomic and Phosphoproteomic Approaches for Deciphering the Signaling Pathway for Tension Wood Formation in Poplar.

    Science.gov (United States)

    Mauriat, Mélanie; Leplé, Jean-Charles; Claverol, Stéphane; Bartholomé, Jérôme; Negroni, Luc; Richet, Nicolas; Lalanne, Céline; Bonneu, Marc; Coutand, Catherine; Plomion, Christophe

    2015-08-07

    Trees adjust their growth following forced changes in orientation to re-establish a vertical position. In angiosperms, this adjustment involves the differential regulation of vascular cambial activity between the lower (opposite wood) and upper (tension wood) sides of the leaning stem. We investigated the molecular mechanisms leading to the formation of differential wood types through a quantitative proteomic and phosphoproteomic analysis on poplar subjected to a gravitropic stimulus. We identified and quantified 675 phosphopeptides, corresponding to 468 phosphoproteins, and 3 763 nonphosphorylated peptides, corresponding to 1 155 proteins, in the differentiating xylem of straight-growing trees (control) and trees subjected to a gravitational stimulus during 8 weeks. About 1% of the peptides were specific to a wood type (straight, opposite, or tension wood). Proteins quantified in more than one type of wood were more numerous: a mixed linear model showed 389 phosphopeptides and 556 proteins to differ in abundance between tension wood and opposite wood. Twenty-one percent of the phosphoproteins identified here were described in their phosphorylated form for the first time. Our analyses revealed remarkable developmental molecular plasticity, with wood type-specific phosphorylation events, and highlighted the involvement of different proteins in the biosynthesis of cell wall components during the formation of the three types of wood.

  20. Jupiter's interior and deep atmosphere: The initial pole-to-pole passes with the Juno spacecraft

    Science.gov (United States)

    Bolton, S. J.; Adriani, A.; Adumitroaie, V.; Allison, M.; Anderson, J.; Atreya, S.; Bloxham, J.; Brown, S.; Connerney, J. E. P.; DeJong, E.; Folkner, W.; Gautier, D.; Grassi, D.; Gulkis, S.; Guillot, T.; Hansen, C.; Hubbard, W. B.; Iess, L.; Ingersoll, A.; Janssen, M.; Jorgensen, J.; Kaspi, Y.; Levin, S. M.; Li, C.; Lunine, J.; Miguel, Y.; Mura, A.; Orton, G.; Owen, T.; Ravine, M.; Smith, E.; Steffes, P.; Stone, E.; Stevenson, D.; Thorne, R.; Waite, J.; Durante, D.; Ebert, R. W.; Greathouse, T. K.; Hue, V.; Parisi, M.; Szalay, J. R.; Wilson, R.

    2017-05-01

    On 27 August 2016, the Juno spacecraft acquired science observations of Jupiter, passing less than 5000 kilometers above the equatorial cloud tops. Images of Jupiter's poles show a chaotic scene, unlike Saturn's poles. Microwave sounding reveals weather features at pressures deeper than 100 bars, dominated by an ammonia-rich, narrow low-latitude plume resembling a deeper, wider version of Earth's Hadley cell. Near-infrared mapping reveals the relative humidity within prominent downwelling regions. Juno's measured gravity field differs substantially from the last available estimate and is one order of magnitude more precise. This has implications for the distribution of heavy elements in the interior, including the existence and mass of Jupiter's core. The observed magnetic field exhibits smaller spatial variations than expected, indicative of a rich harmonic content.