Dissertations / Theses: 'Equilibrium moisture content of wood'

1

Lenth, Christopher Allen. "Wood Material Behavior in Severe Environments." Diss., Virginia Tech, 1999. http://hdl.handle.net/10919/28826.

Full text

Abstract:

An improved knowledge of wood material behavior in hot-pressing environments can provide the benefit of an increased understanding of material properties during the manufacture of wood-based composites as well as insight into the development of new processes and products which manipulate the viscoelastic nature of wood. Two specific areas where additional knowledge is needed are: the high temperature equilibrium moisture content (EMC) behavior and the moisture dependent softening behavior. EMC data was collected and desorption isotherms were generated for mature and juvenile wood of aspen, loblolly pine and yellow-poplar at 50 and 160Â°C. High temperature EMC behavior was found to be distinct from that at lower temperatures, and considerable differences between the isotherms for juvenile and mature wood were detected. Substantial thermal degradation was observed during desorption at 160 Â°C and found to be strongly influenced by relative humidity. The thermal softening behavior of wood was evaluated using dielectric thermal analysis (DETA) at moisture levels from 0 to 20 percent. Coincident in situ relaxations of hemicellulose and amorphous cellulose in the range of 20 to 200 Â°C were observed and found to exhibit the characteristics of a secondary (glass) transition. The moisture dependence of this transition was characterized, and differences in the observed Tg were detected between juvenile and mature wood. Time-temperature superposition was also shown to be applicable to the wood-water system.
Ph. D.

APA, Harvard, Vancouver, ISO, and other styles

2

Zauer, Mario, Frank Meissner, Rudolf Plagge, and André Wagenführ. "Capillary pore-size distribution and equilibrium moisture content of wood determined by means of pressure plate technique." De Gruyter, 2016. https://tud.qucosa.de/id/qucosa%3A38475.

Full text

Abstract:

This paper deals with the determination of the capillary pore-size distribution (CPSD) and equilibrium moisture content (EMC) of untreated and thermally modified (TM) Norway spruce [Picea abies (L.) Karst.] by means of the pressure plate technique (PPT). Desorption experiments were conducted at very high values of relative humidity (RH) in the range between 99.2% and 100%. The thermal modification of spruce results in an alteration of the CPSD, owing to the formation of intercellular cracks in the middle lamella, as a result of cell-wall compression. The desorption curves for both untreated and TM spruce show an extremely upward bend at 99.97% RH. This step reflects an EMC of 38.1% for untreated spruce and 33.8% for TM spruce. None of the samples shrunk during the PPT measurements. Following desorption experiments at 97.4% RH, all samples shrunk. This step reflects an EMC of 27.9% for untreated spruce and 21.7% for TM spruce.

APA, Harvard, Vancouver, ISO, and other styles

3

Tangirala, Phani. "DEVELOPMENT AND VALIDATION OF A SPECIAL PURPOSE SENSOR AND PROCESSOR SYSTEM TO CALCULATE EQUILIBRIUM MOISTURE CONTENT OF WOOD." UKnowledge, 2005. http://uknowledge.uky.edu/gradschool_theses/256.

Full text

Abstract:

Percent Moisture Content (MC %) of wood is defined to be the weight of the moisture in the wood divided by the weight of the dry wood times 100%. Equilibrium Moisture Content (EMC), moisture content at environmental equilibrium is a very important metric affecting the performance of wood in many applications. For best performance in many applications, the goal is to maintain this value between 6% and 8%. EMC value is a function of the temperature and the relative humidity of the surrounding air of wood. It is very important to maintain this value while processing, storing or finishing the wood. This thesis develops a special purpose sensor and processor system to be implemented as a small hand-held device used to sense, calculate and display the value of EMC of wood depending on surrounding environmental conditions. Wood processing industry personnel would use the hand-held EMC calculating and display device to prevent many potential problems that can show significant affect on the performance of wood. The design of the EMC device requires the use of sensors to obtain the required inputs of temperature and relative humidity. In this thesis various market available sensors are compared and appropriate sensor is chosen for the design. The calculation of EMC requires many arithmetic operations with stringent precision requirements. Various arithmetic algorithms and systems are compared in terms of meeting required arithmetic functionality, precision requirements, and silicon implementation area and gate count, and a suitable choice is made. The resulting processor organization and design is coded in VHDL using the Xilinx ISE 6.2.03i tool set. The design is synthesized, validated via VHDL virtual prototype simulation, and implemented to a Xilinx Spartan2E FPGA for experimental hardware prototype testing and evaluation. It is tested over various ranges of temperature and relative humidity. Comparison of experimentally calculated EMC values with the theoretical values of EMC derived for corresponding temperature and relative humidity points resulted in validation of the EMC processor architecture, functional performance and arithmetic precision requirements.

APA, Harvard, Vancouver, ISO, and other styles

4

Lovatti, Lucélio Pietralonga. "Madeira serrada na regi?o sul do Esp?rito Santo: comercializa??o e propriedades." Universidade Federal do Espírito Santo, 2008. http://repositorio.ufes.br/handle/10/6588.

Full text

Abstract:

Made available in DSpace on 2016-12-23T14:37:35Z (GMT). No. of bitstreams: 1 lucelio lovatti.pdf: 1248502 bytes, checksum: c196251467613db326908ba81532337a (MD5) Previous issue date: 2008-03-26
This research had as general objective to obtain information regarding commercialization and physical properties of the sawn wood marketed in the South area of the Esp?rito Santo State. Seventeen wood deposits were visited and collected samples, as well as applied a questionnaire for obtaining of the information. Through the anatomy of the log forty species being marketed as sawn coming mainly of the Amazonia area were identified. Regarding the collected general information, it can highlight, there are no one use of technical specifications established by entities of normalization, so much for the dimensioning of the pieces as for the quality in relation to defects and problems with the drying of the wood, which are commonly marketed green. The behavior hygroscopic in several conditions of relative humidity of the air and the relationships between retratibility and the moisture content of the wood for the main species was studied. The wood used in the study concerning of the behavior hygroscopic and of the retratibility are deriving from the trade of the area and also of the Laborat?rio de Ci?ncias da Madeira (LCM) of the Departamento de Engenharia Florestal of the Univercidade Federal do Esp?rito Santo. For the sorption curves it was observed that each species possesses own a characteristic that means a differentiated behavior among the wood in the several conditions of relative humidity of the air. In relation to the retratibility with the variation in the moisture content of the samples the shrinkages volumetric, radial and tangential not vary exponentially with the loss of water by wood.
A presente pesquisa teve como objetivo geral obter informa??es referentes ? comercializa??o e propriedades f?sicas das madeiras serradas comercializadas na regi?o Sul do Estado do Esp?rito Santo. Foram visitadas dezessete madeireiras e coletadas amostras, bem como aplicado um question?rio para obten??o das informa??es. Atrav?s da anatomia do lenho, foram identificadas quarenta esp?cies sendo comercializadas na forma serrada, provenientes principalmente da regi?o Amaz?nica. Referente ?s informa??es gerais coletadas, se pode destacar, o n?o uso de especifica??es t?cnicas estabelecidas por entidades normalizadoras, tanto para o dimensionamento das pe?as quanto para a qualidade em rela??o a defeitos e problemas com a secagem das madeiras, as quais s?o comumente comercializadas verdes. Para as principais esp?cies, estudou-se o comportamento higrosc?pico em diversas condi??es de umidade relativa do ar e as rela??es entre retratibilidade e o teor de umidade da madeira. As madeiras utilizadas no estudo acerca do comportamento higrosc?pico e da retratibilidade s?o provenientes do com?rcio da regi?o e tamb?m do Laborat?rio de Ci?ncia da Madeira (LCM) do Departamento de Engenharia Florestal da Universidade Federal do Esp?rito Santo. Para as curvas de sor??o, observou-se que cada esp?cie possui caracter?sticas pr?prias, o que significa um comportamento diferenciado entre as madeiras nas diversas condi??es de umidade relativa do ar. Em rela??o ? retratibilidade com a varia??o no teor de umidade das amostras, observou-se que as contra??es volum?trica, radial e tangencial, n?o variam exponencialmente com a perda de ?gua pela madeira.

APA, Harvard, Vancouver, ISO, and other styles

5

Soudek, Pavel. "Teplotně-vlhkostní posouzení prvků krovu s nadkrokevním systémem zateplení." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2014. http://www.nusl.cz/ntk/nusl-226670.

Full text

Abstract:

This thesis deals with the temperature-moisture assessment of members in truss with above-rafter thermal insulation. Within this system it focuses on the details of creating a roof overhang because that is where the timber elements are under the greatest amount of moisture stress. Different variations of this detail are presented including the extent to which thermo-technical requirements and requirements surrounding the built-in timber elements are satisfied. Theoretical calculations are then compared with measurements which were performed on a real building. This task of measurement involved developing a new measuring device. The development of this device is also described in this paper.

APA, Harvard, Vancouver, ISO, and other styles

6

Uherka, Pavel. "Tepelně-vlhkostní analýza konstrukcí masivních dřevostaveb." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2016. http://www.nusl.cz/ntk/nusl-240341.

Full text

Abstract:

This thesis deals with massive wooden buildings especially with regard to the current approach to their design, assessment and approval. In this thesis are shown future possibilities of development of traditional wooden buildings with regard to current thermal technical requirements. Theoretical considerations are then compared with measurements which were performed on massive wooden wall samples.

APA, Harvard, Vancouver, ISO, and other styles

7

Vikberg, Tommy. "Moisture content measurement in the wood industry." Licentiate thesis, Luleå tekniska universitet, Träteknologi, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-18148.

Full text

Abstract:

In the wood industry, determination of the moisture content (mc) with a highaccuracy is of great importance. The green mc is important for optimisation of thewood drying process at sawmills, whereas the mc of dried boards is of interest for thefurther processing and final use of the boards. In the first publication in this thesis,which is a technical report written in Swedish, different measuring techniques withtheir own pros and cons are discussed. A total of 13 different measurement principlesare discussed, focusing on the ability to measure mc in the range of 7-18%. The resultsuggests that mc-meters that use electromagnetic waves in the radio- and microwaveranges have the greatest potential to become the next generation mc-meters for driedboards.The second publication, which is presented in this thesis, investigates the possibilityof measuring the green sapwood mc in pine logs by combining industrial X-rayscanners and 3D-scanners. The method is shown to be suitable for identifying batchesof logs in which the sapwood has begun to dry prior to sawing, rather than predictingthe sapwood mc with high accuracy at the level of individual logs.In a single board, one would ideally like to measure the mc profile over the entirecross section to determine the mc gradient. However, the measured result is affectedin the vicinity of the board edges. In the third publication, the existence of thisproblem is identified, and it is shown that it can be decreased by using correlationfunctions generated by finite element simulations of the measurement system.The fourth publication considers the potential to increase the measurement accuracyof the mc of single boards by combining different measurement techniques.Microwaves, X-rays and visual sorting into different wood quality classes are used. Itis shown that the measurement accuracy is increased by the addition of both the Xraymeasurements and the visual sorting. This result is interesting because visualsorting is usually already present in the final sorting of large sawmills. This is alsowhere the mc measurement preferably is to be performed.
Godkänd; 2012; 20120315 (tomvik); LICENTIATSEMINARIUM Ämnesområde: Träfysik/Wood Physics Examinator: Professor Tom Morén, Institutionen för teknikvetenskap och matematik, Luleå tekniska universitet Diskutant: Teknologie licentiat Björn Källander, Stora Enso Timber AB, Falun Tid: Torsdag den 26 april 2012 kl 10.00 Plats: Hörsal A, Campus Skellefteå, Luleå tekniska universitet

APA, Harvard, Vancouver, ISO, and other styles

8

Hague, James R. B. "Effect of moisture content changes on wood creep." Thesis, Bangor University, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.358374.

Full text

APA, Harvard, Vancouver, ISO, and other styles

9

Rosenkilde, Anders. "Moisture content profiles and surface phenomena during drying of wood." Doctoral thesis, KTH, Civil and Architectural Engineering, 2002. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3456.

Full text

Abstract:

Timber drying is one of the most important processes whenmanufacturing sawn timber products. The drying processinfluences deformations, surface checking, discoloration andhence, the product quality and the manufacturing costs.Research in this field is of great importance for the woodindustry since the industrial drying process always needs to beimproved as market demands increases and new wood products aredeveloped.

The aim of the present thesis was to investigate themoisture transport behaviour in wood based on measurementsduring drying from fresh condition down to end use moisturecontent. The behaviour near the surface interface has beenspecifically investigated since it is of great importance forthe theoretical description of the drying process. Furthermore,studies based on measurements in the wood surface layer duringdrying are not easy to find in the literature. The reason forthat is probably that it is very difficult to make accuratemoisture measurements with high spatial or temporal resolutionwithout disturbing the drying process.

Measurements of moisture content profiles in Scots pineheartwood and sapwood during drying have been performed byusing three different methods. The first was a destructivemethod where the wood samples are sliced with a knife intoseveral smaller pieces. The moisture content in each piece wasdetermined with the dry weight method. The second method usedis non-destructive and it utilises a medical CT-scanner thathas been adapted for drying experiments. The samples are driedin-situ the scanner through the whole experiment. TheCT-scanner measures density and the moisture content arecalculated according to existing methods developed by otherscientists. The third method was also non-destructive and itutilises a Magnetic Resonance Imaging, MRI, technique. Withthis technique the amount of water in the wood sample ismeasured directly even though it has to be calibrated tomoisture content.

The surface emission factor, S, or surface resistance, 1/S,has been studied by performing sorption experiments with MDF ina narrow moisture content range. The experiment was evaluatedusing a simple diffusion model that includes a surface emissionfactor S. The experimental result was compared with resultscalculated using well established boundary layer theories.

Measurements of moisture content profiles in the wood bulkshowed an expected Fickian behaviour at moisture contents belowthe fibre saturation point. Above the fibre saturation pointalmost flat moisture profiles were observed. This behaviour wasnot expected and it is not possible to simulate this behaviourwith the existing drying models since they usually assume thatthere is a gradient in the moisture profile over the wholemoisture content range. From the moisture profiles thediffusion coefficients were determined over a moisture contentranging from 8 to 30%. The values for heartwood and sapwood areapproximately equal in radial and tangential direction tograin. Furthermore, the diffusion values in longitudinaldirection are much higher as expected.

The sorption experiments with MDF gave a greater surfaceresistance compared with the calculation that was based onboundary layer theory. The ratio was three or higher. Thisimplied that there was a greater resistance in the surfacelayer. In addition, this was not well described in theliterature even though a few recent published studiesexist.

High resolution measurements in the surface layer of woodshowed behaviour similar to that observed in the bulk wood. Theresults showed the very early development of a dry zone closeto the surface interface. In that zone or shell the moisturecontent was below the FSP even though the bulk moisture contentwas far above the FSP. At the end of the experiments themoisture content in the surface layer (0300 µm)nearly reached the equilibrium moisture content even though thebulk moisture content still was much higher.

Keywords:Computer tomography, Diffusion, Magneticresonance, Moisture measurements, Moisture profiles, Surfaceemission, Wood drying

APA, Harvard, Vancouver, ISO, and other styles

10

Mugabi, Paul. "Moisture content and drying defects in kiln-dried Eucalyptus grandis poles." Thesis, Stellenbosch : Stellenbosch University, 2007. http://hdl.handle.net/10019.1/4575.

Full text

Abstract:

Thesis (PhD (Forest and Wood Science))--Stellenbosch University, 2007.
ENGLISH ABSTRACT: There has been a reported reduction in the durability of creosote treated, wooden utility poles in South Africa in recent years. Several factors could have been responsible for this. In this study, Eucalyptus grandis pole drying schedules currently used, methods of measurement of moisture content (MC) after drying and drying defects were investigated. Relationships involving drying defects and MC gradient before treatment which may help in the development of simple nondestructive methods of assessing defects such as surface checking, honeycomb and collapse, and MC gradient were also explored. The long term goal of this study was to increase the durability of treated poles by avoiding unacceptable drying defects and MC values before treatment. The results of this investigation are presented in the following chapters: an introduction motivating the aims of the investigations (Chapter 1); a review of literature relevant to MC and drying defects in sawn or round wood (Chapter 2); ready for press manuscripts on MC and drying defects in kiln-dried E. grandis poles (Chapters 3 to 7) and a general conclusion that links up chapters 3 to 7, and recommendations (Chapter 8). The auger drill method gave reliable MC values when samples in increments of 25 mm depths into the pole were taken. However, when single samples of 50 mm and 75 mm depths were considered, the auger drill MC measurements were unreliable. It was concluded that SABS SM 983 (2000), which specifies taking single radial auger drill samples of depth 70±5 mm at pole mid length, is not a reliable method of measuring MC in a kiln-dried E. grandis pole. Correlation results indicated that tree growth factors such as sapwood depth, green MC and heartwood percentage were related to final drying defects and may be used as criteria for pole sorting before kiln drying. Also, the number of valleys per unit length (VPUL) of the circumference at the theoretical ground line (TGL) was positively correlated with honeycomb and closed surface checks, implying that VPUL as a parameter of the pole circumference profile can be used to assess invisible, internal defects. The dry bulb temperature (Tdb) of 80oC, used to dry poles in industry, was too high and resulted into unacceptable levels of drying defects in kiln dried E. grandis poles. In addition, the drying period of 8 days was too short to attain an acceptable MC gradient in poles. It is, therefore, recommended that: To use the auger drill method to reliably determine the moisture content of a pole, samples in increments of 25 mm should be taken. MC measurements should be made at the most critical zones of a pole such as the TGL and not higher up since there is normally considerable MC variation in the longitudinal direction. It is also important to consider sampling more than one position on the pole circumference to cater for the MC variation in the tangential direction. For poles with large sapwood depths i.e. >15mm, mild drying conditions at the beginning of a drying run should be used, since such poles may be more susceptible to surface checking. Poles with large heartwood percentages should also be dried with suitable kiln schedules, i.e. with low Tdb to minimise honeycomb and collapse. In general, Tdb lower than 80oC should be considered in order to reduce the defects to acceptable levels. Poles should be dried for longer than 8 days even at Tdb as high as 80oC to reduce the MC to acceptable values and gradients. Since only three schedules were tested, more drying schedules should be investigated to make reliable conclusions about the effect of schedule on drying defects. In addition, more poles per schedule should be considered in order to obtain statistically reliable results. The relationship of pole diameter and drying defects also requires further investigation. Since a limited sample was used to test for the effect of source of poles and drying schedules on defect correlations, further studies should be done on sufficient samples to come up with more reliable conclusions. It is also necessary to further investigate the possible variation in correlation of VPUL and internal defects on a large sample of poles from specific sources and drying schedules.
AFRIKAANSE OPSOMMING: Die afgelope paar jaar is waargeneem dat kreosootbehandelde transmissiepale 'n afname in duursaamheid toon. Verskeie faktore kan hiervoor verantwoordelik wees. In hierdie studie is huidige Eucalyptus grandis oonddrogingskedules en voggehalte- (VG) bepalingsmetodes vóór en na droging asook drogingsdefekte ondersoek. Verwantskappe tussen drogingsdefekte en VG-gradiënt vóór behandeling wat kan meehelp om nie-destruktiewe metodes te ontwikkel om defekte soos oppervlaktekrake, interne barste en instorting en VG-gradiënt te bepaal, is ook bestudeer. Die langtermyn doelwit van hierdie studie is om die duursaamheid van behandelde pale te verbeter deur onaanvaarbare drogingsdefekte en voggehaltes vóór behandeling te vermy. Die resultate van hierdie ondersoek word in die volgende hoofstukke bespreek: 'n inleiding waarin die doelwitte van die onderskeie ondersoeke motiveer word (Hoofstuk 1); 'n oorsig van die literatuur relevant tot VG en drogingsdefekte in gesaagde en rondehout (Hoofstuk 2); persklaar manuskripte oor VG en drogingsdefekte in oondgedroogde E. grandis pale (Hoofstukke 3 tot 7) en 'n algemene gevolgtrekking wat bevindings uit hoofstukke 3 tot 7 saamvat gevolg deur aanbevelings (Hoofstuk 8). Die augerboor-metode kon betroubare VG-waardes lewer indien monsters van 25mm diepteinkremente in die paal geneem is. Augerboor-voggehaltemetings met enkel 50mm en 75mm monsters was egter onbetroubaar. Daar is bevind dat SABS SM 983 (2000), wat 'n enkel radiale augerboormonster tot op 'n diepte van 70±5 mm in die middel van die lengte van die paal spesifiseer, nie 'n betroubare VG-bepalingsmetode vir oondgedroogde E. grandis pale is nie. Die resultate het aangetoon dat boomgroeifaktore soos spinthoutdiepte, groen voggehalte en die persentasie kernhout aan drogingsdefekte verwant is en as basis vir sortering van pale vóór oonddroging gebruik kan word. Ook kon die aantal valleie per eenheidslengte (e. VPUL) van die omtrek by die teoretiese grondlyn (TGL) positief met interne barste en geslote oppervlaktekrake korreleer word wat impliseer dat VPUL as parameter van die omtrekprofiel van die paal gebruik kan word om onsigbare, interne defekte mee vas te stel. Die droëbaltemperatuur (Tdb) van 80oC wat in die industrie gebruik word, was te hoog omdat dit onaanvaarbare vlakke van drogingsdefekte in oondgedroogde E. grandis veroorsaak het. Daarbenewens was die drogingsperiode van 8 dae by 'n Tdb van 80oC te kort om 'n aanvaarbare VG-gradiënt te lewer. Die volgende word derhalwe aanbeveel: Om betroubare VG-resultate d.m.v. die augerboormetode te verkry, behoort monsters in inkremente van 25mm geneem te word. VG-metings behoort in die mees kritiese dele van 'n paal gedoen te word byv. by TGL en nie hoër nie omdat daar normaalweg beduidende VG-variasie in die longitudinale rigting is. Dis ook belangrik om op meer as een posisie op die omtrek te meet om vir die variasie in die tangensiale rigting voorsiening te maak. Ligte drogingstoestande behoort aan die begin van die drogingsproses by pale met groot spinthoutdieptes, bv. > 15mm, gebruik te word omdat sulke pale meer geneigd tot oppervlaktekrake is. Pale met hoë kernhoutpersentasies moet ook met geskikte drogingskedules, bv. met lae Tdb, gedroog word om interne barste en ineenstorting te verminder. Oor die algemeen behoort Tdb laer as 80oC oorweeg te word om die omvang van defekte by aanvaarbare vlakke te hou. Selfs by Tdb so hoog as 80oC behoort pale langer as 8 dae te droog om die VG tot by aanvaarbare waardes en 'n gradiënt te bring. Omdat slegs drie skedules evalueer is, behoort meer skedules ondersoek word om betroubare gevolgtrekkings oor die effek van skedule op drogingsdefekte te verskaf. Addisioneel behoort meer pale per skedule oorweeg word om statisties betroubare resultate te verkry. Die verwantskap tussen paaldeursnee en drogingsdefekte benodig ook verdere ondersoek. Aangesien 'n beperkte aantal pale gebruik is om die herkoms en drogingskedule met defekte te korreleer, behoort verdere studie op genoeg pale gedoen te word om meer betroubare gevolgtrekkings te kry. Dit is ook noodsaaklik om die moontlike variasie in die korrelasie tussen VPUL en interne defekte op 'n groot aantal pale van spesifieke herkoms en drogingskedules vas te stel.

APA, Harvard, Vancouver, ISO, and other styles

11

van, Dyk Hermanus H. "Ultrasonic Evalutation of Defects and Moisture Content of Lumber." Fogler Library, University of Maine, 2004. http://www.library.umaine.edu/theses/pdf/vanDykHH2004.pdf.

Full text

APA, Harvard, Vancouver, ISO, and other styles

12

Uddin, MD Sharif. "Characterization and modeling of equilibrium moisture content (EMC) properties of wheat /." Search for this dissertation online, 2005. http://wwwlib.umi.com/cr/ksu/main.

Full text

APA, Harvard, Vancouver, ISO, and other styles

13

Edwards, Joseph Richard. "Equilibrium moisture content measurement for porous building materials at various temperatures." Thesis, This resource online, 1996. http://scholar.lib.vt.edu/theses/available/etd-03042009-041243/.

Full text

APA, Harvard, Vancouver, ISO, and other styles

14

Chen, Zhangjing. "Measurement of wood moisture content above fiber saturation point by electrical resistance." Thesis, This resource online, 1993. http://scholar.lib.vt.edu/theses/available/etd-11102009-020203/.

Full text

APA, Harvard, Vancouver, ISO, and other styles

15

Merlan, Maria. "Study and realization of a microwaves system to estimate the moisture content in wood biomass." Thesis, Paris 6, 2016. http://www.theses.fr/2016PA066154/document.

Full text

Abstract:

Le réchauffement climatique est l'un des principaux problèmes de ce siècle. Les politiques européennes soutiennent le développement des énergies renouvelables afin d'atteindre, d'ici 2020, l'objectif fixé par l'Union Européenne (UE). Ce dernier stipule que 20% de l'énergie produite devra provenir d'une source renouvelable. La combustion de la biomasse sous forme de bois est la plus importante des ressources renouvelables. Par conséquent, le développement de celle-ci est fondamental pour atteindre l'objectif de l'UE. Les plaquettes forestières sont des morceaux de bois déchiquetés. Elles présentent de nombreux avantages pour la production d'énergie thermique, en particulier, elles possèdent un bilan carbone neutre. Lors de la combustion, la présence d'eau dans le bois ne produit pas d'énergie mais provoque une perte de chaleur dans le processus de l'évaporation de l'eau. Par ailleurs, plus il y a d'eau moins il y a de bois pour une masse donnée de combustible. De ce fait, la connaissance de la teneur en eau dans le bois permet de déterminer son pouvoir calorifique et donc son prix. Dans cette thèse, plusieurs techniques fondées sur l'étude de la permittivité ont été proposées afin de prédire la teneur en eau des plaquettes forestières à grande échelle. Les systèmes externes fondés sur la réflectivité électromagnétique du matériau sont peu fiables en raison de leur dépendance à l'état de surface du combustible. Celui-ci est très variable en fonction des conditions d'utilisation et climatiques. Les dispositifs internes sont plus performants. Des systèmes internes capacitifs et à base de résonateurs ouverts ont été étudiés. Un prototype de dispositif à résonateur a été réalisé et testé en conditions réelles de production
Global warming is one of the major problems of this century. Thus, European policies support the development of renewable energies in order to reach the target set by the European Union by 2020: 20% of the energy consumption must come from renewable resources. The combustion of wood biomass is the larger of the renewable energies and thus the increase of it is a key factor to get the expected target. Wood chips are shredded wood that present many advantages for the production of thermal energy. In particular, they are considered a carbon neutral fuel. During combustion, the water content does not produce energy but causes a heat loss in the process of the evaporation of the water. Moreover, for a given mass of biofuel, the larger water content, the smaller the wood available. Therefore knowing the moisture content (MC) allows to determine the calorific value of the biofuel and then its price. In this thesis several techniques based upon the study of the permittivity of large samples of wood chips have been proposed to predict the MC. External systems based on measurements of the reflected energy by the material are not reliable because of their dependence on the surface of the fuel, which can be very changeable under rough industrial and weather conditions. Internal devices are more efficient. They are based on either a capacitive technology or on open resonator technology. Due to promising results, a prototype of a resonator device was implemented and tested in real operating conditions

APA, Harvard, Vancouver, ISO, and other styles

16

Kazemi, Sheikh Shabani Seyed Mahmoud. "A study of the physiology of wood inhabiting fungi with regard to oxygen potential and moisture content." Thesis, University of London, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.266062.

Full text

APA, Harvard, Vancouver, ISO, and other styles

17

Koski, A. (Anna). "Applicability of crude tall oil for wood protection." Doctoral thesis, University of Oulu, 2008. http://urn.fi/urn:isbn:9789514287237.

Full text

Abstract:

Abstract Moisture content control is a very effective way of protecting timber. Treatments with environment-friendly, biodegradable tall oil are known to reduce the capillary water uptake of pine sapwood greatly, but despite the good results achieved there have been two problems that limit the use of tall oil for wood protection, the large amount of oil needed and the tendency for the oil to exude from the wood. This work was undertaken in order to obtain an understanding of the mechanism of wood protection by means of crude tall oil (CTO) and to find technical solutions to the main problems limiting its use for industrial wood protection. It is shown that the emulsion technique is one way of solving the first problem, as it provides high water-repellent efficiency at considerably lower oil retention levels. The fact that water is used as a thinner in this technique instead of the commonly used organic solvents is beneficial from environmental, economic and safety points of view. It is also shown that although the drying properties of CTO are inadequate for use as such in wood preservation, its oxidation and polymerization can be accelerated considerably by means of iron catalysts, which prevent the oil from exuding out of the wood. This also increases the water repellent efficiency of CTO treatment. Most impregnation oils do not dry when applied in large quantities, because they hinder the diffusion of air through the wood, which supplies the necessary oxygen. Limiting of the oil uptake by the means of the emulsion technique disturbs the airflow to a lesser extent, and thus enhances the drying process. Hence, both the emulsion technique and the use of an iron catalyst improve both the water-repellent efficiency of tall oil treatment and the rate of drying of the oil, thus solving the two main problems related to wood impregnation with tall oil in one single-stage treatment which can be used in existing wood preservation plants. This is advantageous from both an industrial and an economic point of view.

APA, Harvard, Vancouver, ISO, and other styles

18

Lundgren, Nils. "Modelling microwave measurements in wood /." Luleå, 2005. http://epubl.luth.se/1402-1757/2005/61.

Full text

APA, Harvard, Vancouver, ISO, and other styles

19

Necibi, Semi. "Role of Monochamus carolinensis (Coleoptera: Cerambycidae) and wood moisture content in the regulation of Bursaphelenchus xylophilus (Nematoda: Aphelenchoididae) dispersal stage formation /." free to MU campus, to others for purchase, 1996. http://wwwlib.umi.com/cr/mo/fullcit?p9737902.

Full text

APA, Harvard, Vancouver, ISO, and other styles

20

Vikberg, Tommy. "Industrial Wood Drying : Airflow Distribution, Internal Heat Exchange and Moisture Content as Input and Feedback to the Process." Doctoral thesis, Luleå tekniska universitet, Träteknologi, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-26339.

Full text

Abstract:

At a sawmill, the most energy demanding process is the wood drying. The drying process also has a great impact on quality parameters determined for the boards in the final sorting and thereby affects the sales value to a great extent. The objective of the work described in this compilation thesis was to find ways to improve the industrial wood drying process through better input, feedback and process itself. As input and feedback to the drying process, ways to improve the accuracy in estimating the moisture content (MC) was investigated. For the drying process itself, an investigation of the airflow distribution in a batch kiln at several different fan speeds was performed. Potential energy savings by introducing a new kiln layout was also investigated.To estimate the green MC, i.e. the MC of boards prior to drying, the average green MC of batches rather than individual boards were considered since large batches are handled in the drying anyway. Two different methods were investigated, one method in which the MC of the heartwood was presumed to be constant and a certain relation between the heartwood and sapwood basic density was present. In the other method, the average basic density was estimated as a function of the logs diameters. It was found that both methods worked satisfactory.To improve the accuracy in measuring the MC of the dried boards two approaches were used. The first approach was to combine different measurement techniques, i.e. microwaves and X-rays, to predict the same properties with a multivariate approach. By adding X-ray measurements to microwave measurements, the amount of boards with a predicted MC deviating less than 1% MC from the oven dry reference increased with 7%. The second approach was to investigate the potential of increasing the measurable board area by compensating for the vicinity of the boards edge with aid of a function developed through final element simulations. It was shown that this was possible although the magnitude of the improvement will depend on the actual measurement setup.The airflow distribution in drying was investigated by industrial trials in which the air speed was measured simultaneously at 20 spots throughout the load with the air circulating fans run at a number of different speeds. It was found that the airflow distribution did not change remarkably as a function of the fan speed and once the airflow is measured at a certain fan speed, the effect of changing the fan speed can be estimated using the fan affinity laws. Finally, potential energy savings with a new kiln layout was investigated through drying simulations and associated determinations of the drying air condition in the kiln. It was found that heat savings of roughly 30% could be accomplished in comparison to a kiln with no heat recovery.
Godkänd; 2015; 20150527 (tomvik); Nedanstående person kommer att disputera för avläggande av teknologie doktorsexamen. Namn: Tommy Vikberg Ämne: Träfysik/Wood Physics Avhandling: Industrial wood drying Airflow distribution, Internal Heat Exchange and Moisture Content as Input and Feedback to the Process Opponent: Professor Mihaela Campean, Transilvania University of Brasov, Brasov, Romania Ordförande: Professor Diego Elustondo, Avd för träteknologi, Institutionen för teknikvetenskap och matematik, Luleå tekniska universitet, Skellefteå Tid: Fredag 9 oktober kl 10.00 Plats: Hörsal A i Skellefteå, Luleå tekniska universitet

APA, Harvard, Vancouver, ISO, and other styles

21

Wild, Martha Patricia. "A mechanistic study of VOC and moisture emissions from small softwood pieces." Diss., Georgia Institute of Technology, 2000. http://hdl.handle.net/1853/7070.

Full text

APA, Harvard, Vancouver, ISO, and other styles

22

Ermeydan, Mahmut Ali. "Wood cell wall modification with hydrophobic molecules." Phd thesis, Universität Potsdam, 2014. http://opus.kobv.de/ubp/volltexte/2014/7132/.

Full text

Abstract:

Wood is used for many applications because of its excellent mechanical properties, relative abundance and as it is a renewable resource. However, its wider utilization as an engineering material is limited because it swells and shrinks upon moisture changes and is susceptible to degradation by microorganisms and/or insects. Chemical modifications of wood have been shown to improve dimensional stability, water repellence and/or durability, thus increasing potential service-life of wood materials. However current treatments are limited because it is difficult to introduce and fix such modifications deep inside the tissue and cell wall. Within the scope of this thesis, novel chemical modification methods of wood cell walls were developed to improve both dimensional stability and water repellence of wood material. These methods were partly inspired by the heartwood formation in living trees, a process, that for some species results in an insertion of hydrophobic chemical substances into the cell walls of already dead wood cells, In the first part of this thesis a chemistry to modify wood cell walls was used, which was inspired by the natural process of heartwood formation. Commercially available hydrophobic flavonoid molecules were effectively inserted in the cell walls of spruce, a softwood species with low natural durability, after a tosylation treatment to obtain “artificial heartwood”. Flavonoid inserted cell walls show a reduced moisture absorption, resulting in better dimensional stability, water repellency and increased hardness. This approach was quite different compared to established modifications which mainly address hydroxyl groups of cell wall polymers with hydrophilic substances. In the second part of the work in-situ styrene polymerization inside the tosylated cell walls was studied. It is known that there is a weak adhesion between hydrophobic polymers and hydrophilic cell wall components. The hydrophobic styrene monomers were inserted into the tosylated wood cell walls for further polymerization to form polystyrene in the cell walls, which increased the dimensional stability of the bulk wood material and reduced water uptake of the cell walls considerably when compared to controls. In the third part of the work, grafting of another hydrophobic and also biodegradable polymer, poly(ɛ-caprolactone) in the wood cell walls by ring opening polymerization of ɛ-caprolactone was studied at mild temperatures. Results indicated that polycaprolactone attached into the cell walls, caused permanent swelling of the cell walls up to 5%. Dimensional stability of the bulk wood material increased 40% and water absorption reduced more than 35%. A fully biodegradable and hydrophobized wood material was obtained with this method which reduces disposal problem of the modified wood materials and has improved properties to extend the material’s service-life. Starting from a bio-inspired approach which showed great promise as an alternative to standard cell wall modifications we showed the possibility of inserting hydrophobic molecules in the cell walls and supported this fact with in-situ styrene and ɛ-caprolactone polymerization into the cell walls. It was shown in this thesis that despite the extensive knowledge and long history of using wood as a material there is still room for novel chemical modifications which could have a high impact on improving wood properties.
Der nachwachsende Rohstoff Holz wird aufgrund seiner guten mechanischen Eigenschaften und der leichten Verfügbarkeit für viele Anwendungszwecke genutzt. Quellen und Schrumpfen bei Feuchtigkeitsänderungen des hygroskopischen Werkstoffs Holz limitieren jedoch die Einsatzmöglichkeiten. Ein weiteres Problem stellt der mitunter leichte Abbau – u.a. bei feuchtem Holz - durch Mikroorganismen und/oder Insekten dar. Durch chemische Modifizierungen können die Dimensionsstabilität, die Hydrophobizität und die Dauerhaftigkeit verbessert und damit die potentielle Lebensdauer des Werkstoffes erhöht werden. Dabei ist die dauerhafte Modifikation der Zellwand nur äußerst schwer realisierbar. Inspiriert von der Kernholzbildung in lebenden Bäumen, ein zellwandverändernder Prozess, der Jahre nach der Holzbildung erfolgt, wurden im Rahmen dieser Arbeit neue Ansätze zur chemischen Modifizierung der Zellwände entwickelt, um die Dimensionsstabilität und Hydrophobizität zu erhöhen. Der erste Teil der Arbeit ist stark vom Prozess der Kernholzbildung inspiriert, eine abgeleitete Chemie wurde verwendet, um die Zellwände von Fichte, einem Nadelholz von geringer natürlicher Dauerhaftigkeit, zu modifizieren. Kommerziell verfügbare hydrophobe Flavonoide wurden nach einem Tosylierungsschritt erfolgreich in die Zellwand eingebracht, um so „artifizielles Kernholz“ zu erzeugen. Die modifizierten Holzproben zeigten eine verringerte Wasseraufnahme, die zu erhöhter Dimensionsstabilität und Härte führte. Dieser Ansatz unterscheidet sich grundlegend von bereits etablierten Modifikationen, die hauptsächlich hypdrophile Substanzen an die Hydroxylgruppen der Zellwand anlagern. Der zweite Teil der Arbeit beschäftigt sich mit der Polymerisation von Styren in tosylierten Zellwänden. Es ist bekannt, dass es nur eine schwache Adhäsion zwischen den hydrophoben Polymeren und den hydrophilen Zellwandkomponenten gibt. Die hydrophoben Styren-Monomere wurden in die tosylierte Zellwand eingebracht und zu Polystyren polymerisiert. Wie bei der Modifikation mit Flavonoiden konnte eine erhöhte Dimensionsstabilität und reduzierte Wasseraufnahme der Zellwände beobachtet werden. Im dritten Teil der Arbeit wurde das biologisch abbaubare, hydrophobe poly(ɛ-caprolacton) in der Zellwand aufpolymerisiert. Die Ergebnisse deuten darauf hin, dass Polycaprolacton in der Zellwand gebunden ist und zu einer permanenten Quellung führt (bis zu 5 %). Die Dimensionsstabilität nahm um 40 % zu und die Wasseraufnahmerate konnte um mehr als 35 % reduziert werden. Mit dieser Methode kann nicht nur dimensionsstabileres Holz realisiert werden, auch biologische Abbaubarkeit und damit eine einfache Entsorgung sind gewährleistest.

APA, Harvard, Vancouver, ISO, and other styles

23

Woxblom, Lotta. "Warp of sawn timber of Norway spruce in relation to end-user requirements : quality, sawing pattern and economic aspects /." Uppsala : Swedish Univ. of Agricultural Sciences (Sveriges lantbruksuniv.), 1999. http://epsilon.slu.se/avh/1999/91-576-5860-9.pdf.

Full text

APA, Harvard, Vancouver, ISO, and other styles

24

Clarkson, Christopher Raymond. "The effect of coal composition, moisture content, and pore volume distribution upon single and binary gas equilibrium and nonequilibrium adsorption : implications for gas content determination." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0008/NQ34543.pdf.

Full text

APA, Harvard, Vancouver, ISO, and other styles

25

Persson, Erik. "Storage of spruce pulpwood : effects on wood and mechanical pulp /." Uppsala : Swedish Univ. of Agricultural Sciences (Sveriges lantbruksuniv.), 2001. http://epsilon.slu.se/avh/2001/91-576-6090-5.pdf.

Full text

APA, Harvard, Vancouver, ISO, and other styles

26

Rodrigues, Waldemir. "Determinação do teor de umidade em madeiras por meio de medidores elétricos." Universidade de São Paulo, 1999. http://www.teses.usp.br/teses/disponiveis/88/88131/tde-16092016-111220/.

Full text

Abstract:

A madeira quando seca é um excelente isolante elétrico, porém quando a umidade da madeira aumenta, essa característica diminui fazendo com que esta passe a conduzir a corrente elétrica. A determinação do teor de umidade permite um controle do custo de produção e qualidade da madeira, além de facilitar a utilização de tratamentos preservativos e pintura. O método de determinação do teor de umidade com o uso de estufa é o método mais exato, e por esta razão é utilizado como padrão para calibrar outras técnicas. Por outro lado, a verificação do teor de umidade por meio da estufa é muito demorado e danifica parte do componente a ser analisado. O objetivo deste trabalho é propor uma metodologia para calibrar medidores elétricos de umidade, utilizando espécies de dicotiledôneas nativas e coníferas de florestamento. Na experimentação realizada foi possível constatar que apesar da menor precisão na determinação de teores de umidade, o método que utiliza medidores de umidade do tipo resistência, permite com algumas correções, a obtenção de valores confiáveis para o controle de umidade de peças de madeira serrada. Para isso foram desenvolvidas expressões obtidas por meio de análise de regressão linear que possibilitam fazer as correções necessárias nas leituras realizadas com o medidor elétrico do tipo resistência.
Wood when dry is an excellent electric insulating material. However when the moisture content of wood increases, that feature decreases, which makes it conduct electric current. Determining the moisture content allows the control of the production cost and the quality of the timber, and also facilitates the use of preservative treatments and painting. The method for the determination of the moisture content using the kiln is the most exact method, and therefore it is used as standard to calibrate other techniques. On the other hand, the verification of the moisture content by means of the kiln takes toe much time and damages part of the component to be analyzed. The aim of this work is to propose a methodology to gauge electric moisture meters using species of tropical and forestation hardwood and softwood. The experiments made it possible to verify that, even having less accuracy in determining the moisture content, the method based on moisture electric meters allows, with some adjustments, a reliable data acquisition for the control of moisture content of sawed lumber. For this matter, equations were developed by means of linear regression analysis allowing the necessary corrections of the readings carried out with the electric measurer of the resistance type.

APA, Harvard, Vancouver, ISO, and other styles

27

Antoniadis, Antonios. "Moisture calibration of an R.F based inline moisture sensor : An inline moisture sensor based on radio wave attenuation, Microtec M3 Scan, was calibrated to maximise correlation between real water content in wood and received signal." Thesis, Luleå tekniska universitet, Träteknik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-77359.

Full text

Abstract:

Sensors based on radio waves are used for inline moisture determination in the sawn wood industry. Placed at the final sorting line such a device can be invaluable, giving the operators real time information on the moisture content of the boards passing through. Information that can then be used to improve process control both upstream and downstream. The equipment must first be trained to correlate radio wave attenuation and phase shift to water conten

APA, Harvard, Vancouver, ISO, and other styles

28

Forsberg, Daniel. "Warp, in particular twist, of sawn wood of Norway spruce (Picea abies) /." Uppsala : Swedish Univ. of Agricultural Sciences (Sveriges lantbruksuniv.), 1999. http://epsilon.slu.se/avh/1999/91-576-5853-6.pdf.

Full text

APA, Harvard, Vancouver, ISO, and other styles

29

Logsdon, Norman Barros. "Influência da umidade nas propriedades de resistência e rigidez da madeira." Universidade de São Paulo, 1998. http://www.teses.usp.br/teses/disponiveis/18/18134/tde-21122017-121822/.

Full text

Abstract:

A norma brasileira para o projeto de estruturas de madeira foi alterada, recentemente, abandonando o método determinista das Tensões Admissíveis e adotando o método probabilista dos Estados Limites. Seguindo tendência mundial, a atual norma brasileira, estabelece um teor de umidade de referência de 12%, no qual devem ser reportados os resultados dos ensaios. Dificilmente se conseguirá condicionar, a madeira para o ensaio, com um teor de umidade de exatamente 12%, portanto, será necessário corrigir os resultados do ensaio para este teor de umidade. A atual norma brasileira propõe expressões, para fazer esta correção nas propriedades de resistência e de rigidez da madeira, baseando-se em poucos resultados de ensaios. O objetivo deste trabalho é aferir as expressões propostas pela norma brasileira, sugerindo as alterações necessárias. Uma proposta para a correção da densidade aparente, não prevista na norma brasileira, também será estudada. Para garantir uma base experimental adequada, estuda-se a influência do teor de umidade sobre as propriedades de resistência à compressão paralela às fibras, tração paralela às fibras, cisalhamento paralelo às fibras (no plano radial-longitudinal), bem como sobre o módulo de elasticidade longitudinal e a densidade aparente, em sete diferentes espécies de madeira, correspondentes às sete classes de resistência adotadas pela atual norma brasileira. Conclui-se o trabalho apresentando uma proposta para correção das propriedades de resistência e rigidez ao teor de umidade de 12%. Apresenta-se também uma proposta para a correção da densidade aparente.
The Brazilian Code, NBR 7190/97 - Design of timber structures, was revisited, recently, abandoning the Allowable Stress Method and adopting the States Limits Design Method. Following world tendency, the current Brazilian Code, establishes a reference moisture content of 12%, in which the test\'s results should be registered. It is not possible to keep the specimen, for testing, with exactly 12% moisture content, therefore, it will be necessary to correct the results for this moisture content level. The current Brazilian Code proposes expressions, to do this correction in the strength and stiffness properties of wood, based on few test\'s results. The objective of this work is to judge the expressions proposed by the Brazilian Code, proposing the necessary alterations. A proposal for the correction of the specific gravity, not presented in the Brazilian Code, it will also be studied. To this purpose, the influence of moisture content on the strength in compression and tension parallel to grain, shear parallel to grain (in the radial-longitudinal plane), as well as on the stiffness (modulus of elasticity) and specific gravity, in seven different wood species, corresponding to the seven Brazilian Code strength classes were studied. The conclusions presents a proposal for correction of the strength, stiffness properties and specific gravity, to the 12% moisture content level.

APA, Harvard, Vancouver, ISO, and other styles

30

Moreno, Chan Julian. "Moisture content in radiata pine wood : implications for wood quality and water-stress response : a thesis submitted in fulfilment of the requirements for the degree of Doctor of Philosophy in Forestry, School of Forestry, College of Engineering, University of Canterbury /." Thesis, University of Canterbury. School of Forestry, 2007. http://hdl.handle.net/10092/1217.

Full text

Abstract:

This thesis studied the influence of moisture content on the dynamic estimation of stiffness in wood of Pinus radiata D. Don. This is an important non-destructive measure for estimation of stiffness in standing trees, logs and lumber. Moisture content affects both acoustic velocity and density in the fundamental equation of dynamic MOE (DMOE = V²ρ, where V = acoustic velocity and ρ = density). Investigation included measurements with boards in the laboratory considering moisture contents below and above FSP as well as temperatures below and above 0°C. This also included field measurements of trees in contrasting climate sites and over different seasons including a long drought. Methods for measuring green density and moisture content and the patterns of variation of these parameters were also investigated. A secondary component of this thesis explored the wood quality and some mechanisms of tree response to water stress in two contrasting sites in terms or rainfall and water deficits in a region of Australia. The large increases in DMOE for frozen wood above the FSP (4.5 to 6 GPa) will limit the use of DMOE for grading logs in regions with freezing winters. Results from the experiment remeasuring young trees and the upper range of moisture content and temperatures above 0°C from the experiment with boards showed small to moderate variation in DMOE (0.1 to 1 GPa) which calls for further investigation on analytical procedures for adjustment of DMOE. Such procedures should consider that variations in acoustic velocity and density with changes in moisture content are not proportional and that there are counteracting effects between the two parameters. It remains to be investigated whether the typical variation (under normal climate conditions) in sapwood green density observed in our experiments has some implications for the use of DMOE. On the other hand, it is anticipated that the large differences along the stem and among stands in whole-section green density may bias DMOE measurements in logs for resource assessment. This also needs to be investigated. A comparison between acoustic velocity alone and DMOE for resource assessment under different scenarios is recommended. The study in two contrasting climate sites (high-altitude vs. warm-dry) in the Hume region of Forests NSW, Australia, including young (10-11 years) and mature trees (34 36 years) of radiata pine showed distinctive short and long-term responses of trees to cope with the water-limiting environment. In response to long-term water deficits the warm-dry site developed heartwood and thus reduced sapwood earlier and at faster rates than the high-altitude site. The onset of heartwood formation seemed to be triggered by some site threshold for water use as broadly indicated by the sapwood area/ha. The latter was consistently lower for the warm-dry site across the different stands. The warm-dry site also showed increased short-term responses to water stress and these were interpreted as seasonal mechanisms of the trees to cope with the limiting environment. The trees compensated for the lower available moisture and higher transpiration rates by lowering their saturation and disrupting water conduction at some points (cavitation). The inverse trends of cavitation spots and cavitation bands with height in the stem suggested the trees have different strategies to sacrifice conducting xylem depending on the position on the stem. Finally, it is suggested that saturation tended to fall to critical 'safe' levels as a result of water stress and this varied depending on age, site, and position in the stem. Significant decreases in DMOE and basic density were observed for the warm-dry site and were attributed to lower proportions of latewood due to lower rainfall for that site during the period of latewood formation. These showed no obvious association with any of the long-term water-stress traits (sapwood percentage and number of heartwood rings).

APA, Harvard, Vancouver, ISO, and other styles

31

Luiz, Mariangela Gonçalves. "Medição da umidade no sistema concreto-madeira." Universidade de São Paulo, 2005. http://www.teses.usp.br/teses/disponiveis/11/11150/tde-11112005-164626/.

Full text

Abstract:

A aplicação de um piso de madeira maciça sobre um contrapiso de concreto dá origem a um sistema que une dois materiais com diferentes características higroscópicas, e no qual a movimentação da umidade é ainda um fenômeno pouco conhecido. Visando um melhor entendimento desse fenômeno, a presente pesquisa buscou avaliar diferentes equipamentos para medir o teor de umidade do concreto, desenvolver uma metodologia para quantificar a água evaporável presente no substrato mineral e, a partir desses resultados, sugerir o teor de umidade do substrato mais adequado à aplicação de um revestimento de madeira. Corpos de prova de concreto, preparados com traço 3:1:1 e relação água cimento em torno de 0,5, foram submetidos a secagem ao ar, sendo que a variação do teor de umidade do concreto ao longo do tempo foi acompanhada pela perda de massa e com a utilização de medidores elétricos de umidade do tipo resistência e de contato.. Com o auxílio da análise de regressão foi possível estabelecer equações de correção para as leituras de umidade dos aparelhos. Para a quantificação da água evaporável no concreto, foi desenvolvido um corpo de prova utilizando-se cilindros de MDF com 6,0 cm de comprimento e 4,8 cm de diâmetro, inseridos em tubo de PVC e com uma das extremidades vedada com filme plástico e silicone. O cilindro de MDF mostrou-se um indicador eficiente da presença de água evaporável no concreto, uma vez que as taxas de adsorção pelo MDF puderam ser diretamente correlacionadas às taxas de evaporação pelo concreto. O efeito do adesivo no sistema concreto-madeira foi avaliado através da variação do gradiente de umidade em madeira de Jatobá (Hymenaea sp). Tacos de Jatobá, com dimensões de 100 mm x 80 mm x 18 mm e nos quais foram colocados sensores a 4 mm e a 17 mm de profundidade, foram colados em corpos de prova de concreto utilizando-se adesivo a base de PVA com 60% de sólidos. Os resultados mostraram que a água contida no adesivo não foi totalmente adsorvida pelo taco e o gradiente de umidade no sentido da espessura apresentou relação com o teor de umidade à profundidade de 17 mm, confirmando a hipótese de que existe um fluxo de umidade na interface concreto-madeira.
The application of solid wood flooring over a concrete subfloor originates a system joining two materials with different hygroscopic characteristics, and in which the moisture movement still is a little known phenomena. Looking for the better understanding of moisture relationship in this system, the present research evaluated different equipments to measure concrete moisture content, to develop a methodology to quantify the vaporizable water present in the mineral substrate and, according to these results, to suggest the substrate moisture content more adequate to application of a wooden covering. Sample test of concrete, prepared with trace 3:1:1 and relation water/cement around 0.5, were submitted to air drying and the variation of the concrete moisture content during the process was registered by the mass loss and with the use of electric moisture meters of resistance and contact types. Through regression analysis it was possible to establish equations to correct moisture meters readings. To quantify the vaporizable water present in concrete, a sample test was developed using cylinders of MDF with 6.0 cm of length and 4.8 cm of diameter, inserted in a PVC tube and with one of the extremities closed with plastic film and silicone. The MDF cylinder was an efficient indicator to quantify vaporizable water in the concrete, considering that the moisture adsorption rate of MDF samples could be directly correlated to the concrete evaporation rate. The effect of adhesive in concrete-wood system was evaluated through the variation of moisture content gradient in Jatobá lumber (Hymenaea sp). Flooring samples of Jatobá, with dimensions of 100 mm x 80 mm x 18 mm and moisture sensors inserted at depths of 4 mm and 17 mm, were glued to concrete sample test using a PVA based adhesive with 60% of solids. Results showed that the water contained in the adhesive was not totally adsorbed by the flooring sample and the moisture gradient across sample thickness is correlated to moisture content at depth of 17 mm, what confirm the moisture flow between concrete and wood.

APA, Harvard, Vancouver, ISO, and other styles

32

Godoy, Laura Barbosa Lima Nascimbem de. "Determinação de parâmetros de qualidade em madeira utilizando espectroscopia no infravermelho próximo e calibração multivariada." [s.n.], 2010. http://repositorio.unicamp.br/jspui/handle/REPOSIP/249306.

Full text

Abstract:

Orientador: Ronei Jesus Poppi
Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Química
Made available in DSpace on 2018-08-16T16:50:05Z (GMT). No. of bitstreams: 1 Godoy_LauraBarbosaLimaNascimbemde_M.pdf: 1780795 bytes, checksum: 69eaeca155ecef2bd706747467fc95f5 (MD5) Previous issue date: 2010
Resumo: Neste trabalho, foi utilizada a Espectroscopia no Infravermelho Próximo (NIR) na região de 4.000 ¿ 10.000 cm e modelos de calibração multivariada para a previsão de densidade básica, lignina total e extrativos em madeira. Para isso, foi utilizado o algoritmo dos mínimos quadrados parciais por intervalos (iPLS) obtendo espectros NIR diretamente sobre os cavacos de madeira secos. Um total de 107 e 53 amostras compôs os conjuntos de calibração e validação, respectivamente, sendo a divisão destas amostras realizada pelo algoritmo de Kennard ¿ Stone. A calibração foi otimizada pela eliminação das amostras anômalas (outliers), com base nas amostras com leverage extremo, resíduos não modelados nos dados espectrais e os resíduos com base na repetibilidade espectral. Também foi realizado um estudo visando à classificação e a determinação destes parâmetros em amostras com diferentes teores de umidade. Neste estudo, o método dos mínimos quadrados parciais para análise discriminante (PLS-DA) foi utilizado para a classificação das amostras de acordo com o teor de umidade apresentado e as máquinas de vetores de suporte por mínimos quadrados (LS-SVM) foi utilizada para determinação de cada um dos parâmetros em cada classe com teor de umidade diferente. Os resultados obtidos indicam que os modelos desenvolvidos para os cavacos secos podem ser utilizados na indústria papeleira como alternativa aos métodos convencionais e os modelos desenvolvidos no estudo para as amostras úmidas podem ser utilizados para a classificação de uma amostra desconhecida e, posteriormente, a previsão de cada parâmetro em cada um dos teores de umidade.
Abstract: In this work, it was used the near infrared spectroscopy (NIRS) in region of 4.000 ¿ 10.000 cm and multivariate calibration models to predict basic density, total lignin and extractives in woodchips. The spectra were obtained directly on the dry woodchips and interval partial least squares (iPLS) was used to develop the calibration model. A total of 107 and 53 samples constitute the calibration and validation sets, respectively, split by Kennard ¿ Stone algorithm. The calibration set was optimized by outliers elimination based on data with extreme leverage, unmodelled residuals in spectral data and unmodelled residuals in the dependent variable. It was also performed a study aiming the classification and determination of this parameters in samples with different moisture contents. In this study, the discriminant analysis with partial least squares method (PLS-DA) was used to classify samples according to the moisture content and the least squares supporting vector machines (LS-SVM) was used to determine density, total lignine and extractives in each class with different moisture content. The results indicate that the models developed for the dry woodchips can be used in the pulp and paper industry as an alternative to the conventional methods and the models developed in the study with samples presented different moisture content can be used to classify an unknown sample and to predict each parameter in each moisture content class.
Mestrado
Quimica Analitica
Mestre em Química

APA, Harvard, Vancouver, ISO, and other styles

33

Matsuyama, Yumi. "Toxic Gas and Particulates Characterization in a Smoke Density Chamber." Case Western Reserve University School of Graduate Studies / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=case1557870495018474.

Full text

APA, Harvard, Vancouver, ISO, and other styles

34

Berg, Jan-Erik. "Wood and fibre mechanics related to the thermomechanical pulping process." Doctoral thesis, Mittuniversitetet, Institutionen för naturvetenskap, teknik och matematik, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-6725.

Full text

Abstract:

The main objective of this thesis was to improve the understanding of some aspects on wood and fibre mechanics related to conditions in the thermomechanical pulping process. Another objective was to measure the power distribution between the rotating plates in a refiner. The thesis comprises the following parts: –A literature review aimed at describing fracture in wood and fibres as related to the thermomechanical pulping process –An experimental study of fracture in wood under compression, at conditions similar to those in feeding of chips into preheaters and chip refiners –An experimental study of the effect of impact velocity on the fracture of wood, related to conditions of fibre separation in the breaker bar zone in a chip refiner –A micromechanical model of the deterioration of wood fibres, related to the development of fibre properties during the intense treatment in the small gap in the refining zone –Measurements of the power distribution in a refiner. The fracture in wood under compression was investigated by use of acoustic emission monitoring. The wood was compressed in both lateral and longitudinal directions to predict preferred modes of deformation in order to achieve desired irreversible changes in the wood structure. It was concluded that the most efficient compression direction in this respect is longitudinal. Preferable temperature at which the compression should be carried out and specific energy input needed in order to achieve substantial changes in the wood structure were also given. The fibre separation step and specifically the effect of impact velocity on the fracture energy were studied by use of a falling weight impact tester. The fracture surfaces were also examined under a microscope. An increase in impact velocity resulted in an increase in fracture energy. In the thermomechanical pulping process the fibres are subjected to lateral compression, tension and shear which causes the creation of microcracks in the fibre wall. This damage reduces the fibre wall stiffness. A simplified analytical model is presented for the prediction of the stiffness degradation due to the damage state in a wood fibre, loaded in uni-axial tension or shear. The model was based on an assumed displacement field together with the minimum total potential energy theorem. For the damage development an energy criterion was employed. The model was applied to calculate the relevant stiffness coefficients as a function of the damage state. The energy consumption in order to achieve a certain damage state in a softwood fibre by uniaxial tension or shear load was also calculated. The energy consumption was found to be dependent on the microfibril angle in the middle secondary wall, the loading case, the thicknesses of the fibre cell wall layers, and conditions such as moisture content and temperature. At conditions, prevailing at the entrance of the gap between the plates in a refiner and at relative high damage states, more energy was needed to create cracks at higher microfibril angles. The energy consumption was lower for earlywood compared to latewood fibres. For low microfibril angles, the energy consumption was lower for loading in shear compared to tension for both earlywood and latewood fibres. Material parameters, such as initial damage state and specific fracture energy, were determined by fitting of input parameters to experimental data. Only a part of the electrical energy demand in the thermomechanical pulping process is considered to be effective in fibre separation and developing fibre properties. Therefore it is important to improve the understanding of how this energy is distributed along the refining zone. Investigations have been carried out in a laboratory single-disc refiner. It was found that a new developed force sensor is an effective way of measuring the power distribution within the refining zone. The collected data show that the tangential force per area and consequently also the power per unit area increased with radial position. The results in this thesis improve the understanding of the influence of some process parameters in thermomechanical pulping related wood and fibre mechanics such as loading rate, loading direction, moisture content and temperature to separate the fibres from the wood and to achieve desired irreversible changes in the fibre structure. Further, the thesis gives an insight of the spatial energy distribution in a refiner during thermomechanical pulping.

APA, Harvard, Vancouver, ISO, and other styles

35

Niedzwiecki, Lukasz. "Energy requirements for comminution of fibrous materials - qualitative chipping model." Thesis, Linnéuniversitetet, Institutionen för teknik, TEK, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-12298.

Full text

Abstract:

This paper aims to derive qualitative model for energy requirements for wood chipping process. There is relationship shown between energy requirements and properties of biomass, which is quite variable material. Relationship between comminution machinery and energy necessary for the process is highlighted. Derivation of the model is focused on chipping but in general it’s possible, to make it available both for different types of biomass (f. ex. agricultural residues) or for different type of comminution machinery (f. ex. hammermills) just by using different material properties adjusted to machinery mechanics. Properties used in derivation are mend to be easy to measure. Model is mend to be used as a base for quantitative model that, thanks to measurements performed on real comminution machinery and using wood with known properties, could give answers for two important questions: Would hypothetical changes in desired size of output material increase total system efficiency, taking into consideration lowest efficiency of combustion process (i. ex. higher amounts of unburned fuel)? How to optimise comminution as an operation in biofuel supply chain, with respect to energy used for the process?

APA, Harvard, Vancouver, ISO, and other styles

36

Takeshita, Saly. "Aplicação de tratamentos estabilizadores pós-secagem convencional visando a redução do potencial higroscópico da madeira." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/11/11150/tde-08032016-145819/.

Full text

Abstract:

Além da secagem convencional, a aplicação de tratamentos térmicos a altas temperaturas é um dos processos mais empregados para potencializar a estabilidade da madeira, porém necessitam de estrutura e equipamentos próprios. Diante disto, a proposta desta pesquisa fundamenta-se no estudo da aplicação de tratamentos estabilizadores para redução da higroscopicidade do material madeira, mediante temperaturas mais brandas (abaixo de 150°C) e que permitam a aplicação prática em equipamentos de secagem utilizados na indústria nacional. O objetivo geral deste trabalho foi avaliar os efeitos dos tratamentos estabilizadores nas propriedades físicas e componentes químicos da madeira para sua viabilização prática. O trabalho consistiu em duas etapas, na primeira: foram utilizadas três espécies de folhosas: Cedrinho (Erisma uncinatum), Tachi preto (Tachigali myrmecophyla) e Itaúba amarela (Mezilaurus itauba), foi realizada a caracterização anatômica das espécies utilizando Microscopia Ótica e Microscopia Eletrônica de Varredura (MEV), e análise da composição química e propriedades físicas. As amostras destinadas aos tratamentos estabilizadores, inicialmente, foram secas em estufa convencional e em seguida passaram pelos tratamentos estabilizadores em autoclave a 90°C (24 e 96h) e 120°C (2h e 8h). Em seguida, foram realizados os condicionamentos higroscópicos (adsorção e dessorção) nas umidades relativas de 30, 60 e 90% para avaliação do potencial higroscópico e das variações dimensionais. Na segunda etapa, a partir dos resultados obtidos na primeira etapa, foi possível aplicar o tratamento propriamente dito, o piloto em escala industrial, utilizando uma estufa de secagem convencional (90°C por 24 horas); e em escala laboratorial (90°C por 24 e 96 horas), em uma câmara de climatização simulando um secador convencional. Para o tratamento piloto, foi levado em consideração a disponibilidade de matéria prima da empresa e tendo como foco o trabalho concomitante entre laboratório e aplicação industrial, a espécie utilizada foi o Cumarú (Dipterix sp), uma vez que essa espécie é considerada pela indústria como uma das mais problemáticas e, portanto, uma das espécies prioritárias para receber um tratamento que contribua para reduzir a variação dimensional após secagem. Os principais resultados permitiram observar que os tratamentos estabilizadores na forma em que foram aplicados na presente pesquisa, não causaram alterações na composição química na madeira das espécies e quando realizados em ambiente com alta umidade relativa, não apresentam redução significativa da higroscopicidade e da variação dimensional na maioria dos condicionamentos. Com aplicação do tratamento piloto foi possível observar que com o controle da umidade relativa do ar, tanto no início quanto no final do processo, é possível reduzir o potencial higroscópico da madeira mediante aplicação de tratamentos estabilizadores.
Besides conventional drying, the application of heat treatment at high temperatures is one of the processes employed to improve the stability of wood, however they require its own structure and equipment. Therefore, the purpose of this research is based on the application of the stabilizers treatments studies of wood material hygroscopicity reduction, using low temperatures (below 150°C) and that allows practical application in drying equipment used in the domestic industry. The aim of this study was to evaluate the effects of stabilizing treatments on the physical properties and chemical components of wood for its practical feasibility. The research was comprised for two steps, the first: a total of three species of hardwoods had been used: Cedrinho (Erisma uncinatum), Tachi preto (Tachigali myrmecophyla) e Itaúba amarela (Mezilaurus itauba). The characterization of this three species was made by anatomical description, using Optical Microscope and Scanning Electron Microscopy (SEM), the chemical composition analysis and the physical properties. Samples of the stabilizing treatment, initially, were dried in a conventional kiln dryer and then the stabilizing treatment was applied in an autoclave at 90°C (24 e 96h) e 120°C (2h e 8h). Next, the hygroscopic conditioning were conducted (adsorption and desorption) in relative humidity (RH) of 30, 60 and 90% for evaluation of hygroscopic potential and dimensional changes. In the second stage, from the results obtained in the first step, it was possible to apply the treatment itself, the industrial scale pilot, using a conventional kiln dryer (90°C for 24 hours); and laboratory scale (90°C for 24 and 96 hours) in a climate chamber simulating a conventional dryer. For the pilot treatment, the availability of raw materials in the company was taken into account and focusing on the concurrent work between laboratory and industrial application, the selected specie was Cumarú (Dipterix sp), considered by the industry as one of the most problematic and, therefore a priority species to receive a treatment that can help to reduce the dimensional change after drying. The main results allowed to observe that the stabilizing treatments in the way that were applied in this study, did not cause changes in the chemical composition and when performed in an environment with high relative humidity, show no significant reduction of hygroscopicity and dimensional variation in most of conditionings. From the implementation of pilot treatment was observed that adopting the control of relative humidity, both in the beginning and the end of the process, is possible to reduce hygroscopic potential of wood by applying stabilizers treatments.

APA, Harvard, Vancouver, ISO, and other styles

37

Holmbom, Robin. "Virkesinvägning före torkning : Kan invägning av virkespaket optimera torkningsprocessen?" Thesis, Linnéuniversitetet, Institutionen för skog och träteknik (SOT), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-68125.

Full text

Abstract:

Virkestorkning är ett mycket energikrävande men nödvändigt förädlingssteg för träindustrin. Eftersom energi- och tidsåtgången framförallt är beroende av mängden fukt som ska drivas ur virket så är kännedom om virkets initiala och slutliga fuktinnehåll avgörande för en optimerad process. Industriellt, idag, görs ofta en grov uppskattning av virkets initiala fuktmängd. Denna fuktmängd ligger sedan till grund för torkningens genomförande och dess resultat. I föreliggande arbete undersöks huruvida invägning av virkespaketen före torkning kan användas för att bestämma virkets fuktinnehåll och hur detta kan bidra till att optimera torkprocessen. 17 fullständiga torkningsförsök genomfördes på ett konventionellt sågverk i norra Sverige. I försöken vägdes virkespaketen och torkningsscheman anpassades därefter.Genom mätningar av virkets fuktkvot och jämförelse med tidigare torkning där konventionella torkningsscheman använts så kunde det konstateras att paketvägningen bidrar till en förbättrad och optimerad torkningsprocess.
Drying is a very energy-intensive but important process in the wood industry. Since the amount of energy used is, more or less, proportional to the amount of water released, the measurement of the initial and final wood moisture content is crucial to optimize the process. Today, a rough estimate of the initial wood moisture content is used as dryer operation input data. The process could be improved by a more accurate determination of the initial moisture level. The present work examines if weighing the wood can be used as a method to determine the wood moisture level and how this can optimize the drying process. 17 drying trials were conducted at a sawmill in northern Sweden. The wood was weighed and new drying schedules were constructed and adjusted accordingly. The result show that weighing the wood results in more accurate drying schedules and overall an optimized drying process.

APA, Harvard, Vancouver, ISO, and other styles

38

SOUSA, Marcondes Barreto de. "Processo de desintoxicação da torta de mamona de destinada a ração animal: secagem e simulação." Universidade Federal de Campina Grande, 2013. http://dspace.sti.ufcg.edu.br:8080/jspui/handle/riufcg/239.

Full text

Abstract:

Submitted by Josirene Barbosa (josirene.henrique@ufcg.edu.br) on 2018-01-25T12:14:24Z No. of bitstreams: 1 MARCONDES BARRETO DE SOUSA - TESE PPGEP 2013.pdf: 2754211 bytes, checksum: cfa419eec5485d15508d11ab77a2eeed (MD5)
Made available in DSpace on 2018-01-25T12:14:24Z (GMT). No. of bitstreams: 1 MARCONDES BARRETO DE SOUSA - TESE PPGEP 2013.pdf: 2754211 bytes, checksum: cfa419eec5485d15508d11ab77a2eeed (MD5) Previous issue date: 2013-02
Capes
A torta de mamona é o principal subproduto da cadeia produtiva da mamona, produzida a partir da extração do óleo das suas sementes. Em todo o mundo, seu uso predominante tem sido como adubo orgânico, apesar do seu elevado teor de proteínas. A torta é produzida na proporção aproximada de 1,2 tonelada para cada tonelada de óleo extraída. A elevada produção de biocombustíveis a partir das sementes de mamona ocasionará um aumento na produção da torta, a qual, apesar do alto valor nutritivo, não pode ser empregada para o consumo animal por possuir proteínas tóxicas (ricina) e alergênicas (albumina 2S). O objetivo deste trabalho foi estudar métodos de desintoxicação e secagem da torta de mamona para que seja possível seu aproveitamento como ração para animais. A caracterização e a composição química, físico-química e física da torta “in natura” foram constituídas pelas análises dos teores de água, óleo, proteína bruta, carboidratos, ricina, pH, acidez titulável, cinzas, fibras, valor calórico e calor específico. A umidade de equilíbrio da torta de mamona foi determinada pelo método estático, em soluções de sais e água destilada, para uma faixa de umidade relativa de 10, 30, 50,70 e 90%, nas temperaturas de 15, 25, 35 e 45°C. As amostras da torta de mamona foram colocadas dentro de recipientes herméticos contendo soluções de sais, em câmara com temperatura controlada, até atingir o equilíbrio. Para o ajuste das isotermas de sorção da torta de mamona foram utilizados os modelos de Halsey, Henderson modificado por Thompson, Oswin e Cavalcanti Mata, e os dados experimentais submetidos a uma análise de regressão não linear, utilizando-se programa computacional Statistica7.0. Exceto o modelo de Oswin, os demais descreveram suficientemente o comportamento das isotermas de umidade de equilíbrio para as umidades relativas e temperaturas estudadas, com valores dos coeficientes de determinação (R2) superiores a 99% e desvios percentuais médios (P) inferiores a 10%. Constatou-se que a umidade de equilíbrio higroscópico é diretamente proporcional à atividade de água e decresce com o aumento de temperatura, para um mesmo valor de atividade de água. O processo de desintoxicação da torta de mamona foi feito à base de hidróxido de cálcio Ca(OH)2, em solução aquosa, nas concentrações de 1, 2, 3, 4 e 5%. A secagem da torta de mamona foi feita nas temperaturas de 50, 60, 70, 80 e 90°C, em um secador de leito fixo, em camadas fina, com ajustes satisfatórios dos modelos matemáticos de Henderson, Page, Midilli e Cavalcanti Mata. A secagem em camada espessa ocorreu nas temperaturas de 50, 70 e 90°C, nas concentrações de 1, 3 e 5% e as xix isotermas ajustadas pelo modelo de Thompson, apresentando coeficiente de determinação superior a 99%. Após tratamento e secagem, foi realizada a quantificação da torta de mamona referente aos parâmetros químicos e físico-químicos, constando-se alterações dos teores de pH e acidez, causadas pelo aumento da concentração; quanto ao teor de ricina, verificou-se que quanto maior a concentração de hidróxido de cálcio presente no tratamento e a temperatura de secagem, maior foi sua remoção, atingindo 0% de ricina na concentração de 5% e temperatura de secagem de 90°C, podendo, portanto, ser utilizada na alimentação de animais.
The castor bean is the main by-product of castor oil production chain, produced from the extraction of oil from its seeds. Around the world, its use has been rife as organic fertilizer, despite its high protein content. The bean is produced in the ratio of approximately 1.2 tons for every ton of oil extracted. The high production of bio-fuel from the seeds of castor lead to an increase in the production of the bean, which, despite its high nutritional value, cannot be used for animal consumption, for possessing toxic protein (ricin) to allergen (2S albumin). The aim of this work was to study methods of detoxification and drying of castor bean to be able to take advantage of it as animal feed. The characterization and chemical, physical-chemical and physical composition of the bean "in nature" were established by analysis of the levels of water, oil, protein, carbs, ricin, pH, nameable acidity, ash, fiber, calories and specific heat. The humidity equilibrium contained in castor bean was determined by the static method, in salt solutions and distilled water to a relative humidity range of 10, 30, 50, 70 and 90% at temperatures of 15, 25, 35 and 45° C. Samples from the castor bean were placed in sealed containers containing salt solutions in a chamber with controlled temperature, until they achieve equilibrium. For adjustment of the sorption isotherms of the castor bean Halsey, Henderson, modified by Thompson, Oswin and Cavalcanti Mata models were used, and experimental data subjected to nonlinear regression analysis using a computer program Statistica7.0. With the exception of the Oswin model, the others sufficiently described the behavior of the humidity equilibrium isotherms for the relative humidity and studied temperatures, with the values of the coefficients of determination (R2) superior to 99% and average percent deviations (P) inferior to 10%. We found that the humidity of hygroscopic equilibrium is directly proportional to the water activity and decreases with the increase of temperature, to the same value for water activity. The detoxification process of the castor bean was made by basic hydrated calcium hydroxide Ca(OH)2 in aqueous solution at concentrations of 1, 2, 3, 4 and 5%. The drying of castor beans was made at temperatures of 50, 60, 70, 80 and 90° C, in a fixed bed dryer, in thin layers, with satisfactory adjustments of the mathematical models of com Henderson, Page, Midilli and Cavalcanti Mata. The thick layered drying xxi occurred in temperatures of 50, 70 and 90°C, in the concentrations of 1, 3 and 5% and the isotherms adjusted by the Thompson model, showing a coefficient of determination superior to 99%. After treatment and drying, the quantification of the castor bean was done, referring to the chemical and physical-chemical parameters, finding alterations in the pH content and acidity, caused by the increase in concentration; as to the ricin content, it was verified that the higher the concentration of calcium hydroxide present in the treatment and the drying temperature, the more it was removed, reaching 0% of ricin in the concentration of 5% and the drying temperature of 90°C, making it edible for animals.

APA, Harvard, Vancouver, ISO, and other styles

39

Susin, Felipe. "AVALIAÇÃO DE PROGRAMAS DE SECAGEM PARA MADEIRAS DE EUCALIPTO ELABORADOS COM BASE EM TESTES PRÉVIOS A ALTA TEMPERATURA." Universidade Federal de Santa Maria, 2013. http://repositorio.ufsm.br/handle/1/8726.

Full text

Abstract:

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
The difficulty of obtaining dry wood with a low incidence of defects is a challenge when it comes to eucalyptus wood, since the species of this genus exhibit drying difficult and high expression of defects, contributing to their use is limited and the level of losses on many occasions raised. The main objective of this study was to develop and evaluate programs for drying wood Corymbia citriodora, Eucalyptus robusta and Eucalyptus saligna. For this, it was evaluated drying parameters and physical characteristics of the species in preliminary tests, using equations to establish the drying programs for each species. Underwent two batches of 32 tablets with 270,0 x 15,0 x 2,5 (length, width and thickness), respectively, of each kind, drying using the same drying program for each species. For each batch, we used four control samples to monitor the moisture content and four boards for the evaluation of moisture gradients during drying and standardization phase. The programs were evaluated for drying the drying rate, the manifestation of defects, the final moisture content, the shrinkage, moisture gradient and the standardization phase. The drying rate in the application of drying programs maintained the trend presented during the preliminary assessment, with values equal to 5,38 x10-4, 1,10 x10-3 e 7,96x10-4 g/cm³.h for Corymbia citriodora, Eucalyptus robusta and Eucalyptus saligna, respectively. For the final moisture content, the three species showed variation satisfactory, and the Corymbia citriodora showed less dispersion between the parts, followed by Eucalyptus saligna and Eucalyptus robusta. The qualitative assessments showed that the wood, in general, the species which obtained the best results was Corymbia citriodora, followed by Eucalyptus saligna robust and Eucalyptus. The same trend was observed for the contractions during drying was not observed for the species difference between the coefficient anisotropic. The time used for the standardization step is only sufficient for Eucalyptus robusta, the moisture content which presented below 4% after the end of the standardization.
A dificuldade de obter-se madeira seca com reduzida incidência de defeitos é um desafio quando se trata de madeira de eucalipto, visto que as espécies deste gênero apresentam secagem difícil e elevada incidência de defeitos, contribuindo para que a sua utilização seja limitada e o nível de perdas, em muitas ocasiões, elevado. O objetivo principal deste estudo foi elaborar e avaliar programas de secagem para madeira de Corymbia citriodora, Eucalyptus robusta e Eucalyptus saligna. Para isso, avaliaram-se parâmetros de secagem e características físicas das espécies em ensaios prévios, utilizando equações para elaborar os programas de secagem para cada uma das espécies. Submeteram-se dois lotes, com 32 tábuas de 270,0 x 15,0 x 2,5 cm (comprimento, largura e espessura), respectivamente, de cada espécie, à secagem utilizando o mesmo programa de secagem para cada espécie. Para cada lote, utilizaram-se quatro amostras de controle para o monitoramento do teor de umidade e outras quatro tábuas para as avaliações dos gradientes de umidade, durante a secagem e na fase de uniformização. Os programas de secagem foram avaliados quanto a taxa de secagem, manifestação de defeitos, o teor de umidade final, retratibilidade, gradiente de umidade e etapa de uniformização. A taxa de secagem na aplicação dos programas de secagem manteve a tendência apresentada durante a avaliação prévia, com valores iguais a 5,38x10-4, 11,0x10-4 e 7,96x10-4 g/cm2.h, respectivamente para o Corymbia citriodora, Eucalyptus robusta e Eucalyptus saligna, sendo que as mesmas apresentaram massa específica básica de 0,82, 0,61 e 0,69 g/cm³, respectivamente. Para o teor de umidade final, as três espécies apresentaram variação satisfatória, sendo que o Corymbia citriodora mostrou a menor dispersão entre as peças, seguido pelo Eucalyptus saligna e Eucalyptus robusta. As avaliações qualitativas da madeira indicaram que, de modo geral, a espécie que obteve os melhores resultados foi o Corymbia citriodora, seguida pela de Eucalyptus saligna e pela de Eucalyptus robusta. A mesma tendência foi verificada para as contrações durante a secagem, não se verificando diferença entre as espécies para o coeficiente anisotrópico. O tempo aplicado para a etapa de uniformização foi suficiente apenas para o Eucalyptus robusta, o qual apresentou gradientes de umidade abaixo de 4% após o final da uniformização.

APA, Harvard, Vancouver, ISO, and other styles

40

Portugal, Edilberto Princi. "Influencia de fungos micorrizicos arbusculares, sistemas de cultivo e parametros pos-colheita na concentração de esteviosideos e desenvolvimento de Stevia rebaudiana (BERT.) Bertoni." [s.n.], 2006. http://repositorio.unicamp.br/jspui/handle/REPOSIP/257095.

Full text

Abstract:

Orientador: Sylvio Luis Honorio
Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agricola
Made available in DSpace on 2018-08-08T08:41:42Z (GMT). No. of bitstreams: 1 Portugal_EdilbertoPrinci_D.pdf: 3108115 bytes, checksum: 834974ae808b2dc8cae3ca812f9976ba (MD5) Previous issue date: 2006
Resumo: A Stevia rebaudiana, um arbusto que tem na produção de esteviosídeos seu principal produto de interesse, foi objeto deste trabalho. Considerando sua cadeia produtiva, existem lacunas que necessitam pesquisas, tanto no aspecto agronômico, como o emprego de espécies fúngicas micorrízicas, quanto procedimentos pós-colheita, dos quais a secagem é um dos fatores. O presente trabalho teve como objetivos, identificar uma espécie de fungo micorrízico arbuscular eficiente e sua relação com o desenvolvimento e concentração de esteviosídeos em plantas de estévia, cultivadas em campo, hidroponia e aeroponia, selecionar substrato adequado para o desenvolvimento da colonização micorrízica, avaliar sistemas de secagem no teor de esteviosídeos e determinar as isotermas de sorção da estévia. Para seleção de fungo micorrízico foram testadas sete espécies, sendo cinco de um banco de culturas e duas isoladas da própria cultura da estévia. O ensaio foi conduzido em casa de vegetação em vasos com solo esterilizado e cinco repetições. Foram determinados a massa seca total da parte aérea e de folhas, teor e quantidade acumulada de esteviosídeos nas folhas e colonização micorrízica. Para seleção de substratos, foram testados nove produtos comerciais, utilizando-se como planta indicadora uma gramínea (Brachiaria humidicola) e como parâmetro avaliado a taxa de colonização fúngica no sistema radicular. Plantas de estévia inoculadas ou não com o fungo micorrízico Glomus intraradices foram cultivadas em três sistemas distintos, campo, aeroponia e hidroponia. Foram realizadas três colheitas em épocas distintas e determinada a massa da matéria seca total da parte aérea e de folhas, teor e acúmulo de esteviosídeos nas folhas e colonização micorrízica. Foram testados três processos de secagem, ao sol, secador a gás e estufa elétrica com circulação forçada de ar, à temperatura de 45oC. Os processos foram avaliados em função do teor de esteviosídeos nas folhas. A determinação da umidade de equilíbrio nas folhas de estévia foi realizada nas temperaturas de 30 e 45oC e, as isotermas de sorção foram tratadas com os modelos matemáticos de BET, BET linear, Peleg, GAB, Halsey, Langmuir, Oswin, Henderson e Chung e Pfost. A espécie Glomus intraradices foi a mais eficiente para o desenvolvimento da estévia e acumulação de esteviosídeos. O substrato Rendmax Citrus sem adubação propiciou as melhores condições para a colonização micorrízica nas raízes da gramínea. Dentre os sistemas de cultivo estudados a hidroponia mostrou-se o menos eficiente para o cultivo de estévia. Em aeroponia obteve-se maior produtividade em termos de matéria seca da parte aérea, enquanto no campo maior quantidade acumulada de esteviosídeos. Não se observou diferença entre a secagem na estufa e no secador para qualquer das épocas de colheita. O teor de esteviosídeos nas folhas de plantas secadas ao sol foi sempre inferior, com perda de até 20% em relação aos outros dois sistemas. Os modelos que apresentaram melhor ajuste, nas temperaturas de 30 e 45oC, foram GAB e HALSEY. O modelo BET LINEAR também mostrou bom ajuste, mas somente para a temperatura de 45oC
Abstract: Stevia rebaudiana, a shrub mostly interesting for its production of steviosides, was the object of this work. In regard to its productive chain, further researches must be done, not only in agronomical aspects, but also in the utilization of mycorrhizal fungal species, as well as in the post-harvest processes, namely the drying one. The present work aimed at the identification of an efficient arbuscular mycorrhizal fungal species and its influence in the development and concentration of steviosides in stevia plants grown in hydroponic and aeroponic systems; to select an adequate substrate for the development of mycorrhizal fungi; to evaluate drying systems in steviosides rates and to determine stevia?s isotherms of sorption. For the mycorrhizal fungi selection seven species were tested, five from a germplasm bank and two were isolated from their own stevia culture. Five assays in pots with sterilized soil were carried out in a greenhouse. The total dry mass of the aerial parts and of the leaves, the rate and accumulated quantity of steviosides in the leaves as well as the mycorrhizal colonization were determined. Nine commercial substrates were tested for the rate of colonization of the root system of an indicating gramineous plant (Brachiaria humidicola). Stevia plants that were inoculated (or not) with the mycorrhizal fungus Glomus intraradices were cultivated in three different growing systems, field, aeroponic and hydroponic. Three harvests were carried out in different periods and the total dry mass of the branch and leaves sections, contents and accumulated steviosides in the leaves and mycorrhizal colonization were determined. Three processes for drying leaves were tested: by sunlight, gas dryer and electrical stove with forced air circulation, at 45oC. The processes were evaluated in relation to the steviosides rate of the leaves. The equilibrium moisture content for stevia leaves was done at 30oC and 45oC, while the isotherms of sorption were tested for the best fit by mathematical models of BET, BET linear, Peleg, Gab, Halsey, Langmuir, Oswin, Henderson and Chung and Pfost. The Glomus intraradices species was the most efficient for the stevia development and accumulation of steviosides. The Rendmax Citrus substrate without manure rendered the best conditions for the mycorrhizal colonization in the gramineous roots. Among the growing systems studied, hydroponics turned out to be the least efficient for stevia cultivation. Aeroponics brought the highest production in terms of dry mass from the aerial parts, while in the field a larger accumulated quantity of steviosides was obtained. No difference was observed between the stove and gas drying processes at any of the harvesting periods. The steviosides rate from the leaves dried by sunlight was always inferior, coming to a loss of 20% in relation to the others. The best fit models were GAB and HALSEY. The BET LINEAR fitted by 45ºC
Doutorado
Tecnologia Pós-Colheita
Doutor em Engenharia Agrícola

APA, Harvard, Vancouver, ISO, and other styles

41

Umoru, Joseph Adejo. "Characteristics assessment of aspen logs used in the production of matches." Thesis, Linnéuniversitetet, Institutionen för skog och träteknik (SOT), 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-75913.

Full text

Abstract:

Aspen (Populus tremula L.) accounts for about 2% of the total wood stock in Sweden. Sawmills use only a small part (about 5,000 m³fub) of round wood aspen per year. Since there are no Swedish gradings and design values for aspen, no aspen is used for structural purposes. This also applies to other hardwood trees in Sweden. Aspen is mainly used for pulp and paper with a mass consumption of 800,000 m³fub per year of which about 50% is imported. Most imported aspen is from Russia and the Baltics. The other major use of aspen is in match industries. Consumption for matches amounts to approximately 30,000 m³fub per year in Sweden. The aim of the research work was to increase knowledge on the wood quality of aspen used in the production of matches. Aspen (Populus tremula L.) logs were collected from two different sites in Sweden and a non-destructive tools weas used to estimate the modulus of elasticity in logs. To measure the dynamic modulus of elasticity (MOEdyn), Fakopp resonance log grader used. Other properties like density and moisture content were measure and were correlated with the MOEdyn values in order to identify the site that has a better log quality. Besides, horizontal and vertical variation of different wood properties were measured and compared within and between trees from two different sites in order to justify the variation of log quality. A total of 20 trees from Askaremåla and Vimmerby, Sweden were felled and used in this study. From each tree, 3 m long logs were sampled from each base, middle and top. After that, non-destructive evaluations were performed in those logs. Besides, 5 cm thick discs were collected in every tree height (base, middle and top) to measure horizontal and vertical variations. This study shows that there were differences in MOEdyn between and within trees. It was evident that trees collected from Vimmerby had a better log property than that in Askaremåla. Using non-destructive tools, it is possible to sort out quality logs for the production of Swedish matches.

APA, Harvard, Vancouver, ISO, and other styles

42

Melaku, Eneyew Tadesse. "Evaluation of Ethiopian nigerseed (Guizotia abyssinica Cass) production, seed storage and virgin oil expression." Doctoral thesis, Humboldt-Universität zu Berlin, Landwirtschaftlich-Gärtnerische Fakultät, 2015. http://dx.doi.org/10.18452/17130.

Full text

Abstract:

Das Ziel der experimentellen Arbeit war die Untersuchung der Einflussfaktoren auf den Ertrag, die Saatgutqualität unter verschiedenen Lagerungsbedingungen sowie die Effizienz der Expression vonRamtillkraut (Guizotia abbysinica Cass.). In Feldversuchen wurden folgende Varianten untersucht, Sorten ‚Fogera‘ und ‚Kuyu‘, Saatgutaufwand von 5, 10, 15 kg ha-1, ein Stickstoffaufwand von 13, 23 und 33 kg ha-1, sowie eine differenzierte Wasserversorgung an zwei Standorten (Adet und Koga). In Adet wurde der höchste Saatgut Ertrag mit 1.384,60 kg ha-1 ermittelt, Erträgen in Koga (ohne Bewässerung) mit 1.064,72 kg ha-1 und 967,00 kg ha-1 (mit Bewässerung). Der höchste Ölgehalt wurde im Saatgut aus Koga (ohne Bewässerung) mit 41,54% ermittelt, gefolgt von Koga (mit Bewässerung) 39,59% und Adet mit 38,67%. Signifikante Unterschiede wurden zwischen den N-Aufwandmengen in Koga mit Bewässerung und Saatgutmengen in Adet ermittelt. Die Unterschiede bei den Fettsäuregehalten in Adet waren nicht signifikant. Der Alpha-Tocopherol Gehalt betrug 80 mg pro 100 g bei hoher Saatdichte und hoher N-Düngung. Hinsichtlich des Verfahrens des Ölpressens, wurde ein signifikanter Unterschied zwischen Effizienz und Temperatur ermittelt. Die Dauer der Konditionierung und die Vorschubgeschwindigkeit sind negative korreliert gleichfalls mit der Effizienz der Expression. Die Temperaturen von 70°C und 80°C zeigten keinen signifikanten Einfluss auf die Ölausbeute, dagegen war der der Einfluss von 90°C statistisch signifikant.
The aim of this study was to investigate factors influencing seed yield, postharvest handling, and the oil expression efficiency for nigerseed (Guizotia abbysinica Cass.). Based on field study on two varieties, two locations, three seed rates and three fertilizer rates the highest mean nigerseed yield was 1384.6 kg ha-1 at Adet location (rain fed) followed by location Koga (rain) with 1064.7 kg ha-1 and Koga (irrigation) with 967.0 kg ha-1 showing significant difference. The oil content by location was 41.54% for Koga (rain) followed by 39.59 and 38.67% for Koga (irrigation) and Adet (rain) respectively showing significant difference whereas the Ash content showed a reverse trend of oil content. Fatty acid composition did not show significant difference in any treatment. Significant mean alpha-tocopherol of 80 mg/100 g (70 to 89 mg/100 g) was attained for increasing seed and nitrogen rates. Based on two temperatures and seven relative humidities model evaluation and monolayer moisture content estimation, Guggenheim-Anderson-de Boer (GAB) models was found to best suit both varieties as compared to Brunauer-Emmet-Teller (BET), and modified Chung &Pfost. For oil expression efficiency, 90ºC seed conditioning showed significant effect compared to 80 and 70ºC however conditioning times and feed rates did not differ significantly.

APA, Harvard, Vancouver, ISO, and other styles

43

Ekanayake, Jagath C. "Soil water movement through swelling soils." Lincoln University, 1990. http://hdl.handle.net/10182/1761.

Full text

Abstract:

The present work is a contribution to description and understanding of the distribution and movement of water in swelling soils. In order to investigate the moisture distribution in swelling soils a detailed knowledge of volume change properties, flow characteristics and total potential of water in the soil is essential. Therefore, a possible volume change mechanism is first described by dividing the swelling soils into four categories and volume change of a swelling soil is measured under different overburden pressures. The measured and calculated (from volume change data) overburden potential components are used to check the validity of the derivation of a load factor, ∝. Moisture diffusivity in swelling soil under different overburden pressures is measured using Gardner's (1956) outflow method. Behaviour of equilibrium moisture profiles in swelling soils is theoretically explained, solving the differential equation by considering the physical variation of individual soil properties with moisture content and overburden pressure. Using the measured volume change data and moisture potentials under various overburden pressures, the behaviour of possible moisture profiles are described at equilibrium and under steady vertical flows in swelling soils. It is shown that high overburden pressures lead to soil water behaviour quite different from any previously reported.

APA, Harvard, Vancouver, ISO, and other styles

44

Betiol, Lilian Fachin Leonardo [UNESP]. "Estudo das isotermas de adsorção do bagaço de mandioca proveniente da indústria de fécula." Universidade Estadual Paulista (UNESP), 2016. http://hdl.handle.net/11449/145009.

Full text

Abstract:

Submitted by LILIAN FACHIN LEONARDO BETIOL null (lilianfacleo@hotmail.com) on 2016-12-04T18:12:23Z No. of bitstreams: 1 Tese - Formatada (1) Corrigida.pdf: 1975637 bytes, checksum: a2ca74a2f726452b217e860e0c11c866 (MD5)
Approved for entry into archive by Felipe Augusto Arakaki (arakaki@reitoria.unesp.br) on 2016-12-06T13:52:01Z (GMT) No. of bitstreams: 1 betiol_lfl_me_sjrp.pdf: 1975637 bytes, checksum: a2ca74a2f726452b217e860e0c11c866 (MD5)
Made available in DSpace on 2016-12-06T13:52:01Z (GMT). No. of bitstreams: 1 betiol_lfl_me_sjrp.pdf: 1975637 bytes, checksum: a2ca74a2f726452b217e860e0c11c866 (MD5) Previous issue date: 2016-11-21
As isotermas de sorção tornaram-se importantes para prever o comportamento da cinética de secagem e as condições de armazenamento de resíduos da indústria alimentícia. O conhecimento de tal propriedade é útil para projetar equipamentos ou operações para fins de armazenamento ou processamento. O bagaço quando é apenas descartado, representa um desperdício de matéria prima, de compostos orgânicos com categoria bioquímica definida (proteínas, açúcares, ceras, graxas, resinas), que poderia ser aproveitada. Dentro deste contexto, a presente pesquisa teve como objetivo caracterizar quimicamente o bagaço de mandioca e fazer a determinação experimental das isotermas de sorção destes resíduos da indústria de fécula, além de calcular a entalpia e entropia, temperatura media harmônica e calor isostérico de adsorção. Para isso, o teor de umidade de equilíbrio nas isotermas de sorção, de bagaço de mandioca, foi determinado utilizando o método gravimétrico estático nas temperaturas de 20 a 80 °C. Modelos teóricos e empíricos foram usados para representar os valores experimentais das isotermas de sorção, sendo que o modelo de GAB foi o que apresentou os melhores ajustes. Utilizando o modelo de GAB foi possível determinar o calor isostérico de adsorção como função do teor de umidade. A teoria da compensação foi confirmada pela relação linear entre entalpia e entropia. Maiores valores de temperatura isocinética do que a temperatura harmônica reforçam a teoria da compensação e sugeriram que a adsorção de água pelo bagaço de mandioca é considerado um processo conduzido pela entalpia.
The sorption isotherms become important to predict the drying kinetics behavior and waste storage conditions of the food industry. The knowledge of such property is useful for designing equipment or operations for storage or processing. The bagasse is only when discarded, is a waste of raw materials, organic compounds with defined biochemical category (proteins, sugars, waxes, greases, resins), which could be harnessed. Within this context, this study aimed to chemically characterize the Cassava Bagasse and make the experimental determination of the sorption isotherms of these starch industry waste and calculates the enthalpy and entropy, harmonic average temperature and isosteric heat of adsorption. For this, the equilibrium moisture content in the sorption isotherms of cassava bagasse was determined using the gravimetric static method in temperatures 20-80 ° C. Theoretical and empirical models were used to represent the experimental values of sorption isotherms, and the GAB model was the one that presented the best fit. Using the GAB model was possible to determine the isosteric heat of adsorption and moisture content of the function. The theory of compensation was confirmed by the linear relationship between enthalpy and entropy. Isokinetic higher temperature values than the harmonic temperature reinforce the theory of compensation and suggested that the adsorption of water by mancioca bagasse and considered one of enthalpy driven process.

APA, Harvard, Vancouver, ISO, and other styles

45

Wentzel, Maximilian. "Process optimization of thermal modification of Chilean Eucalyptus nitens plantation wood." Doctoral thesis, 2019. http://hdl.handle.net/11858/00-1735-0000-002E-E5A0-2.

Full text

APA, Harvard, Vancouver, ISO, and other styles

46

SHE, YA-XIANG, and 佘雅翔. "Equilibrium moisture content and drying rate of shiitake." Thesis, 1990. http://ndltd.ncl.edu.tw/handle/71921726093695706243.

Full text

APA, Harvard, Vancouver, ISO, and other styles

47

Becerra, Ochoa Fernando Amador. "Evaluation of six tools for estimating woody biomass moisture content." Thesis, 2012. http://hdl.handle.net/1957/37209.

Full text

Abstract:

Woody biomass transportation costs and market values/costs are strongly correlated with the woody biomass moisture content. Properly managing moisture content can potentially lead to economic and environmental advantages in biomass energy markets. Good management requires accurate moisture content measurements. Therefore, availability of accurate, precise, reliable, and efficient tools to assess woody biomass moisture content is essential. In this study, six different tools (Fibre-Gen HM200, IML Hammer, Humimeter BLW, Timbermaster, Humimeter HM1 and Wile Bio Meter) were evaluated. The six tools employed three different measurement technologies; acoustic, conductance, and capacitance. Woody biomass samples were collected over one season (summer 2011) at three different locations in western Oregon (Corvallis, Dallas, and Clatskanie) for three softwood species and three hardwood species: Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), Ponderosa pine (Pinus ponderosa L.), western hemlock (Tsuga heterophylla (Raf.) Sarg.), hybrid poplar (Populus spp.), Madrone (Arbutus spp.), and Garryana Oak (Quercus garryana Dougl. ex Hook). Twenty 3-meter long log (20 to 400mm diameter) specimens were collected per species; 18 specimens were divided into two different treatments (open vs. covered), and the two remaining specimens were chipped. In addition, approximately 100 kilograms per species of hogfuel (limbs and tops) were collected and chipped. Moisture content measurements of logs, chips, and hogfuel were made regularly over a four month period. These data was used to develop multiple linear regression models for assessing the moisture content of the six species using the six tools. The major factors considered in the regression models were species (6), treatment (2), and tools (6). The data were also used to estimate the sample size needed for each tool. The best tool from each technology type was identified. The results generated from this study show that (1) none of the tools are accurate without calibration for different species, (2) the best model/tool combination could only explain about 80% of the variability in measurements, (3) further product development is required in some cases to ensure that the tools are robust for industrial application, and (4) there is a wide range in efficiency of the tools (i.e., 50 minute tool efficiency range). The Fibre-Gen HM200 and Wile Bio Meter were the most accurate, precise and efficient tools tested. The cost of transporting woody biomass from the forest to woody biomass plants is "optimized" when the moisture content drops to approximately 30% (wet basis). Validation of the models developed for three of the tools tested (Fibre-Gen HM200, Humimeter BLW and the Wile Bio Meter) indicates that the tools are accurate below 35% MC (wet basis). This suggests they could be used for making threshold transportation decisions, i.e., determining when to haul.
Graduation date: 2013

APA, Harvard, Vancouver, ISO, and other styles

48

van, Dyk Hermanus H. "Ultrasonic evaluation of defects and moisture content of lumber /." 2004. http://www.library.umaine.edu/theses/theses.asp?highlight=1&Cmd=abstract&ID=FTY2004-008.

Full text

APA, Harvard, Vancouver, ISO, and other styles

49

Wallace, John Wilkes. "Drying and equalization of western hemlock to Japanese equilibrium moisture content." Thesis, 2001. http://hdl.handle.net/2429/12736.

Full text

Abstract:

Density sorted, matched-samples of Western hemlock {Tsuga heterophylla (raf.)[SargP were dried in three different drying technologies in order to quantify the physical changes of kiln dried wood when exposed to the equilibrium moisture contents of a typical Japanese winter. Moisture sorption and desorption was monitored for 14 weeks by sampling board weight, dimensions, shell and core moisture contents and warp. All three technologies, a conventional kiln, a radio frequency vacuum kiln and a superheated steam vacuum kiln are capable of drying to a target average moisture content of 19% at the core with acceptable standard deviation. Product quality was good with all three drying technologies. The difference of 7% in equilibrium moisture content between Tokyo and Vancouver is large enough to elicit a response in shell moisture content, dimensions and warp. However, the responses found should be expected when wood is examined in context of its natural variability. Drying Western hemlock to 19% moisture content at the core should be considered the maximum target MC. A target MC of 15% moisture content at the core would optimize the drying time and stability as the lumber is equalized to Japanese conditions.

APA, Harvard, Vancouver, ISO, and other styles

50

Barker, Jason Scot. "The effects of moisture content and initial heterotrophic colonization on the decomposition of coarse woody debris." Thesis, 2003. http://hdl.handle.net/1957/32268.

Full text

Abstract:

Previous research on coarse woody debris (CWD) indicated that moisture content and initial heterotrophic colonization of decaying wood can affect the decomposition process. Six heterotrophic treatments were created to simulate the effects of physical penetration of the bark and wood and the transmission of ascomycetes versus basidiomycetes into CWD. In 1995, 360 Douglas-fir (Pseudotsuga menziesii) were randomly placed at five replicate sites in old-growth stands. Each site had 6 heterotrophic (HET) x 2 moisture combinations (TENT). One set of logs representing the treatment combinations was used for sampling respiration and another set was used to measure volume affected by insect gallery excavations and fungal rot and to determine decay rates. Respiration was sampled three times during the summer of 2001. The results indicated that the HET treatments were no longer affecting respiration rates. Analysis of the average of the three sampling periods revealed no TENT effect but examinations of the individual sampling dates suggests that tented logs might have higher respiration rates than non-tented logs as summer progresses. In the aggregate, the TENT treatment reduced moisture content from 45% to 36%, a 20 percent reduction in moisture levels. The HET and the TENT treatments did not affect decay rates. The mean density change for the logs was -0.072 g/cm�� 0.03 and the mean decay constant was 0.026 �� 0.011. The TENT treatment did affect heterotrophic activity. The mean volume of wood borer excavation and extent of brown rot was higher in the tented logs (256 cm��) than in the non-tented logs (59.9 cm��). There was also a statistically significant interaction between the HET and TENT treatments. The largest differences in volume affected by wood borers and fungal rot were found in treatments that injected ascomycetes into the experimental logs. In sum, there was limited evidence that the differences in moisture content caused by the TENT treatment affected the decomposition process but the HET treatments appear to not be directly influencing decomposition after six years. The findings suggest differences in the initial community composition of heterotrophs have a decreasing impact on the decomposition process as it progresses.
Graduation date: 2004

APA, Harvard, Vancouver, ISO, and other styles

Dissertations / Theses on the topic 'Equilibrium moisture content of wood'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles