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ELABORATION OF A DRYING SCHEDULE FOR Eucalyptus spp HYBRIDS CLONES WOODS
Celso Gon?alves Barbosa,José Tarcísio Lima,Sebasti?o Carlos da Silva Rosado,Paulo Fernando Trugilho
CERNE , 2005,
Abstract: The elaboration of adequate drying schedules is essential to produce high quality conventional kiln dried lumber.Eucalyptus woods are particularly difficult to dry, and, for this reason, it is desirable that the drying schedule be carefullydeveloped. The objectives of this work were to elaborate a drying schedule for woods of ten Eucalyptus hybrids clones and toverify the propensity of these woods to post drying defects. For this purpose, it was applied the methodology of drastic drying at100°C, which associates intensity of defects, time and rate of drying, presented by small wood samples, with the behaviourto be presented by lumber after the conventional drying. The results allowed developing a drying schedule common to the tenclone lumbers. This program is based on an initial temperature of 40°C, final temperature of 66°C and drying potential equal to2.2. The drying time can be reduced, if the clones were grouped in accordance to their drying rate. The clones presented lowpropensity to split and high propensity to collapse.
DRYING BEHAVIOR AND PERMEABILITY OF Eucalyptus grandis LUMBER
Jankowsky,Ivaldo P; Santos,Gilson Roberto V. dos;
Maderas. Ciencia y tecnología , 2005, DOI: 10.4067/S0718-221X2005000100002
Abstract: although the increasing economic importance of eucalyptus lumber to furniture and other value added products manufacturing, its industrial use is still small. one of the main reasons is the difficulty to dry the lumber and related loses of raw material. there is a general recommendation in literature to use a low drying rate in initial stages of the process, and changing to a more aggressive drying after removal of liquid water from the lumber. according classical theory about drying of porous material, this point should coincide with the predominance of diffusion phenomena in the moisture movement; which could be determined through the characteristic drying curve of the material. with the objective to get better knowledge about the drying of eucalyptus grandis lumber, its characteristic drying curve was determined, and the results proved that eucalyptus grandis lumber is not permeable to liquid flow. based on its characteristic drying curve, it is possible to suggest the change of drying conditions when lumber moisture content, dry basis, is between 35% and 40%, then starting a more aggressive drying
DRYING BEHAVIOR AND PERMEABILITY OF Eucalyptus grandis LUMBER  [cached]
Ivaldo P Jankowsky,Gilson Roberto V. dos Santos
MADERAS : Ciencia y Tecnología , 2005,
Abstract: Although the increasing economic importance of Eucalyptus lumber to furniture and other value added products manufacturing, its industrial use is still small. One of the main reasons is the difficulty to dry the lumber and related loses of raw material. There is a general recommendation in literature to use a low drying rate in initial stages of the process, and changing to a more aggressive drying after removal of liquid water from the lumber. According classical theory about drying of porous material, this point should coincide with the predominance of diffusion phenomena in the moisture movement; which could be determined through the characteristic drying curve of the material. With the objective to get better knowledge about the drying of Eucalyptus grandis lumber, its characteristic drying curve was determined, and the results proved that Eucalyptus grandis lumber is not permeable to liquid flow. Based on its characteristic drying curve, it is possible to suggest the change of drying conditions when lumber moisture content, dry basis, is between 35% and 40%, then starting a more aggressive drying
INFLUENCE OF BOARDS DIAMETRICAL POSITION AND STEAMING ON THE DRYING DEFECTS OF Eucalyptus grandis.
Fred Willians Calonego,Elias Taylor Durgante Severo
CERNE , 2007,
Abstract: This study evaluated the Eucalyptus grandis drying defects acting on boards diametrical position and on log steaming. Half of the logs, with diameter from 20 to <25, 25 to <30 and 30 to <35cm, were steamed during 20 hours at 90oC of temperature. Subsequently, the logs (control and steamed) were sawn. The boards were dried in the dry-kiln pilot and the resulting defects from the drying process were measured. The results indicate that: (1) the boards coming from control logs presented different magnitude defects in function of the diametrical position. The split and spring to increase in direction to pith, the bow to increase in direction to bark and cupping were bigger in intermediary boards; (2) the boards coming from steamed logs presented a reduction from drying defects in function of logs diameter and its more homogeneous index in the pith-bark direction.
Mathematical modeling of the drying process of corn ears
Corrêa, Paulo Cesar;Botelho, Fernando Mendes;Oliveira, Gabriel Henrique Horta;Goneli, André Luis Duarte;Resende, Osvaldo;Campos, Sílvia de Carvalho;
Acta Scientiarum. Agronomy , 2011, DOI: 10.4025/actasciagron.v33i4.7079
Abstract: the objective of this work was to study and model the drying process of corn ears at different air temperatures. thermodynamic properties associated with the drying process of this product were also determined. corn ears with initial moisture content of 0.45 dry basis (kgw kgdm-1) were dried until they reached a final moisture content of 0.12 (kgw kgdm-1) at temperatures of 45, 55 and 65°c. traditional models used to describe the drying process of several agricultural products were employed to fit the observed data of the drying process of corn ears. the effective diffusion coefficient (def) was determined by means of an analytical solution of fick's second law. it was concluded that the logarithmic model was the one that best fit the observed data representing the drying process. def values increased with temperature increases, ranging from 5.490 x 10-10 to 1.163 x 10-9 m2 s-1. based on the dependence of the drying constant of the logarithmic model with temperature, thermodynamic properties were determined, concluding that the drying kinetics variation is dependent on the energy contributions of the surrounding environment.
Wood quality of Eucalyptus grandis dominant and average trees submitted to drying  [PDF]
Joel Telles de Souza,R?mulo Trevisan,Luciano Denardi,Diego Martins Stangerlin
CERNE , 2012,
Abstract: This study determined, in trees of dominant and average diameter, the influence of air seasoning followed by kiln drying in the sawn wood quality of 14 years old stand of Eucalyptus grandis W. Hill ex Maiden, located in Capivari do Sul municipality, state of Rio Grande do Sul. The sampling of trees was performed after a pilot inventory on the basis of the dominant and average diameter at breast height (DBH). After cutting down the trees, there were selected the logs located between the DBH and 25% of commercial height. The logs were then sawn using into boards that were submitted to air seasoning from green up to 18% of moisture content, followed by kiln drying until 13% of moisture content. End checking and board crook were evaluate after sawing, following air seasoning and kiln drying. The results indicate that, both for dominant and average trees, end checking and board crook were not influenced by different wood process stage. However, the contrast between dominant and average trees shows that the magnitude of defects is higher in the average trees.
Air drying of logs from an Eucalyptus urophylla clone for carbonization use  [PDF]
Raphael Nogueira Rezende,José Tarcísio Lima,José Reinaldo Moreira da Silva,Alfredo Napoli
CERNE , 2010,
Abstract: Wood drying is one of various stages in the carbonization process, therefore proper monitoring is key to improving yield and obtaining quality charcoal. Prior to being subjected to carbonization by charcoal production plants and once trees have been felled, logs are piled up by the roadside or close to carbonization furnaces and left air drying for 90 days until an optimal 30% moisture content is reached. This work aims to evaluate air drying of logs from a Eucalyptus urophylla stand for carbonization use, gauging moisture loss throughout and also the influence of log diameter and bark. Logs with and without bark were used, 6.0cm to 21.0cm in diameter, 3.60m in length, with average basic density of 0.496 g/cm3, obtained from a commercial stand owned by V&M Florestal Ltda at age 8 years. Air drying log piles were arranged outdoors in Paraopeba/MG and monitoring consisted of periodic log weighing for a period of 80 days. At the end of the experiment, higher rates of moisture loss were observed in the three initial weeks. Moisture in logs without bark (54%) and with bark (50%) was close after 80 drying days, with a higher level of moisture reduction being observed for logs without bark. Bark influence on moisture loss was more pronounced in the first three weeks. Moisture reduction varied in intensity as a function of log diameter. After 80 days, the highest level of moisture reduction was observed in logs without bark: 65% for logs larger in diameter and 80% for logs smaller in diameter. As regards logs with bark, results were 56% and 75% respectively.
DRYING PROCESS MONITORING
DIACONESCU IOANA,GRIGORESCU LUIZA
Journal of Engineering Studies and Research , 2010,
Abstract: To produce a good quality material, after the drying process, with minim power specific consumption, it has to know the material isotherm of sorption. For an analytical determination of material isotherm of sorption it has to make a drying mathematical model. This allowed us to know in every moment the local temperature and the moisture content of the material.
PERFORMANCE OF INBRED AND OUTBRED Eucalyptus spp.
Regiane Abjaud Estopa,Magno Antonio Patto Ramalho,Gabriel Dehon Sampaio Pe?anha Rezende,Jupiter Israel Muro Abad
CERNE , 2007,
Abstract: Inbred and outbred Eucalyptus clone were assessed aiming to check the possible loss of vigor in the initial germinationphases and growing in nursery and in t field conditions. Offsprings from two commercial clones were assessed as inbreds (C01 andC02) and as hybrids (C01 x C03 and C02 x C03). The work consisted of two phases. The first one was in the nursery, in a completelyrandom design, with 4 treatments and 6 reps, in plots with 30 tubes with only one seed. The second one, in the field, used a randomizedcomplete block design, with 4 treatments and 6 reps, with 18 plants per plots. The percentage of germination, germination speed index,survival and plant height were assessed at 35, 50, 65 and 80 days in the nursery and, in the field, the percentage of survival with 6months and plant height with 2, 4 and 6 months. It was concluded that the germination, survival and the growing of plants resultedfrom inbred were similar to the hybrid, showing that the loss of vigor is not expressive for those characters in initial developmentalphases of Eucalyptus spp.
Theoretical Modeling and Experimental Analysis of Drying Process in Electromagnetic Field  [PDF]
Arif Memmedov, Teymuraz Abbasov, Mustafa ?eker
World Journal of Engineering and Technology (WJET) , 2014, DOI: 10.4236/wjet.2014.21005
Abstract: The effects of electromagnetic waves in drying processes of solid materials are investigated theoretically and experimentally. Modified model of mass transfer being constituted by the effect of electromagnetic waves which have different frequency has been obtained. Modeling of the drying process with a two-port electric circuit for the determination of diffusion coefficients is designed. The frequency limits of electromagnetic wave which will be able to hasten the drying process are determined. The effects of the electromagnetic wave in the potato slice drying process by the influence of different frequencies and temperatures are experimentally examined. The results obtained are compared with theoretical calculations. Moisture concentration curves in drying process have been commented by drawing. Theoretical and experimental results which have been obtained are identified as a well adaptation.
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