THE OBJECTIVE OF THIS PAPER IS TO SUMMARIZE RECENT TRENDS RELATED TO INDUSTRIAL KILN DRYING WITH ESPECIAL EMPHASIS ON THE DRYING OF SOFTWOOD DIMENSION LUMBER IN CANADA. THE PAPER EXPLORES FUTURE TRENDS BY ANALYZING THE CURRENT MARKET CONDITION AND WOOD PRODUCTS REQUIREMENTS. THE PAPER ALSO SUMMARIZES CURRENT RESEARCH DEVELOPMENTS IN THE AREA OF KILN LUMBER DRYING THAT WAS PUBLISHED BY CANADIAN UNIVERSITIES AND RESEARCH INSTITUTES. THIS INCLUDES BASIC RESEARCH, SUCH AS WOOD PHYSICS AND COMPUTER SIMULATION, AND APPLIED RESEARCH, SUCH AS NON-CONVENTIONAL DRYING STRATEGIES AND NEW TECHNOLOGIES AND SENSORS. A LAST NOTE IS ALSO INCLUDED TO MENTION A KILN SUPERVISOR TOOL THAT WAS DEVELOPED IN CANADA TO ANALYZE INFORMATION RELATED TO KILN PERFORMANCE INDICATORS. THE KILN SUPERVISOR PROVIDES IMPORTANT TRENDS FOR MILLS AIMING TO OPTIMIZE THEIR DRYING PROCESSES AND REALIZE GAINS WITHOUT SUBSTANTIAL INVESTMENTS IN CAPITAL AND OTHER RESOURCES.

THERMAL MODIFICATION PROCESSES ARE ENVIRONMENTALLY FRIENDLY METHODS USED TO IMPROVE CERTAIN PROPERTIES OF WOOD. CURRENTLY, WOOD FROM THINNING OF YOUNG PLANTATIONS OF NOTHOFAGUS ALPINA (RAULÍ) IN CHILE IS BEING EVALUATED TO OBTAIN VALUE BEFORE THE PLANTATION HAS REACHED MATURITY. THE OBJECTIVE OF THIS PAPER WAS TO ASSESS SELECTED PROPERTIES OF THERMALLY MODIFIED WOOD OF YOUNG (14- TO 25-YEARS-OLD) N. ALPINA WOOD THAT COMES FROM THINNING OF TWO SITES WITH INTENSIVE SILVICULTURE AND ONE SIMILAR TO A SECONDARY GROWTH FOREST. TO ACHIEVE THIS, NON-DESTRUCTIVE TESTS WERE CARRIED OUT TO MEASURE SOME CHEMICAL-CRYSTALLINE CHARACTERISTICS, AS WELL AS PHYSICAL AND MECHANICAL PROPERTIES; THE DIFFERENCES BETWEEN THE 25%, 50%, AND 75% DISTANCE FROM PITH TO THE BARK IN EACH SITE WAS STUDIED. THE MODIFICATION TEMPERATURES USED WERE 170, 190, AND 210 °C. THE RESULTS SHOW THAT THINNING WOOD FROM N. ALPINA CAN BE THERMALLY MODIFIED WITH FAVORABLE RESULTS, THUS PRESENTING AN OPTION TO OBTAIN VALUE WHILE THE PLANTATION REACHES MATURITY, PARTICULARLY THE THINNING WOOD FROM THE INTENSIVE FORESTRY REGIMES, WHICH PRESENTED MOST HOMOGENEOUS RESULTS, ESPECIALLY AT THE MODIFICATION TEMPERATURE OF 190 °C.

COLLAPSE IS ALMOST CERTAIN TO OCCUR IN THE INDUSTRIAL DRYING OF EUCALYPTUS NITENS AND, AS SUCH THIS PREVENTS THE LUMBER MANUFACTURING INDUSTRY IN CHILE FROM PRODUCING COMMERCIAL SOLID WOOD PRODUCTS FROM THIS SPECIES. THIS PROBLEM IS STILL UNSOLVED, AND DIFFERENT STUDIES TO REDUCE COLLAPSE ARE CURRENTLY UNDERWAY. IN THIS EXPLORATORY STUDY, SHRINKAGE AND COLLAPSE AFTER DRYING OF EUCALYPTUS NITENS WAS MEASURED FOR BOARDS CUT FROM DIFFERENT RADIAL LOCATIONS WITHIN THE STEM (CORE, TRANSITION, AND OUTER WOOD FROM PITH TO BARK) AND HAVING DIFFERENT ANNUAL RING ORIENTATIONS (FLAT-SAWN AND QUARTER-SAWN). THOUGH EXPLORATORY, THE RESULTS APPEAR TO CONFIRM THAT PIECES THAT WERE CUT FROM THE CENTER OF THE TREES WERE LESS SUSCEPTIBLE TO COLLAPSE THAN PIECES CUT FROM THE TRANSITION ZONE BETWEEN THE CENTER AND THE PERIPHERY. ON AVERAGE, COLLAPSE IN TRANSITION WOOD WAS APPROXIMATELY 50% HIGHER THAN THE COLLAPSE OBSERVED IN WOOD CUT FROM THE CENTRAL ZONE OF THE TREES.

PREVIOUS STUDIES WITH RADIATA PINE TREES GROWING SLIGHTLY LEANED TOWARDS ONE SIDE SHOWED THAT THEY HAVE SMALL AMOUNTS OF COMPRESSION WOOD WITH DIFFERENT CHARACTERISTICS THAN THE OPPOSITE WOOD AT THE OTHER SIDE OF THE ANNUAL RINGS. THESE DIFFERENCES INCLUDE SHORTER TRACHEIDS, HIGHER DENSITY, HIGHER PROPORTION OF LINING, HIGHER PROPORTION OF EXTRACTIVES IN TOLUENE ETHANOL, AND A SMALLER AMOUNT OF ALPHA-CELLULOSE. THE PRESENT STUDY COMPARES THE PROPERTIES OF KRAFT PULP, WITH AND WITHOUT BLEACHING, FOR MIXTURES OF COMPRESSION AND OPPOSITE WOOD OBTAINED FROM FIFTEEN 22-YEAR-OLD RADIATA PINE TREES THAT GREW IN HUMID SAND SOILS OF CHILE. THE KRAFT PULP MIXTURE WAS STUDIED FOR DIFFERENT PROPORTIONS OF 0, 40, 70 AND 100% COMPRESSION WOOD. CONSIDERING ALL MIXTURES WITH AND WITHOUT BLEACHING, THE STUDY REPORTS VALUES BETWEEN 501 AND 695 KG/M3 DENSITY, 28 AND 51 NM/G TENSION INDEX, 18 AND 25 MNM2/G TEAR INDEX, 2,2 AND 4,1 KPAM2/G BURST INDEX, AND 44% AND 50,6% PULP YIELD.......

THE MAIN OBJECTIVE OF THE PRESENT WORK IS THE DEVELOPMENT OF AN ORIGINAL TWO-DIMENSIONAL NUMERICAL SIMULATION OF WOOD DRYING, BASED ON THE WATER POTENTIAL CONCEPT USING THE CONTROL VOLUME FINITE ELEMENT METHOD (CVFEM). THE MATHEMATICAL MODEL WAS BASED ON A SET OF NON-LINEAR SECOND PARTIAL DIFFERENTIAL EQUATIONS, WHICH WERE SOLVED BY A NUMERICAL PROCEDURE USING CVFEM. RESULTS OF DRYING CURVES AND ISOCONCENTRATIONS ARE SHOWN FOR ASPEN (POPULUS TREMULOIDES) SAPWOOD AND COMPARED WITH NUMERICAL AND EXPERIMENTAL DATA. FURTHERMORE, THE IMPACT OF THE VARIATION OF VARIOUS NUMERICAL PARAMETERS WAS STUDIED TO EVALUATE THE ALGORITHMS CONSISTENCE. IT HAD BEEN CONCLUDED THAT THE CURRENT NUMERICAL METHOD WAS CONSISTENT AND ALLOWS TO SIMULATE WOOD DRYING SATISFACTORILY RESULTING IN DETAILED INFORMATION ABOUT WOOD MOISTURE CONTENT DISTRIBUTION.

NEW EXPERIMENTAL DATA IS PRESENTED FOR THE MECHANO-SORPTIVE COEFFICIENT OF EUCALYPTUS NITENS WOOD ANALYZED IN THE LONGITUDINAL DIRECTION THROUGH THE PRINCIPLE OF TOTAL DEFORMATION SUPERPOSITION. THE PROCEDURE WAS BASED ON THE DETERMINATION OF THE PARTIAL STRAIN COMPONENTS: ELASTIC STRAIN, FREE SHRINKAGE STRAIN, AND MECHANO-SORPTIVE STRAIN. THE METHODOLOGY INCLUDED THE DESIGN OF CANTILEVER FLEXION TESTS OF A WOODEN BEAM IN AN AIR-CONDITIONED ENVIRONMENT WITH VARIABLE RELATIVE HUMIDITY. THESE CONDITIONS MADE IT POSSIBLE TO ESTIMATE EACH OF THE DEFORMATION COMPONENTS SEPARATELY AND THEN TO DETERMINE THE MECHANO-SORPTIVE COEFFICIENT USING THE RHEOLOGICAL STRESS-STRAIN MODEL. DEFORMATIONS AND DISPLACEMENTS WERE EVALUATED WITH EXTENSOMETERS AND DISPLACEMENT SENSORS, RESPECTIVELY, IN CONDITIONS OF 0 TO 30% OF THE BREAKING LOAD APPLIED PERPENDICULARLY TO BEAMS ORIENTED IN THE LONGITUDINAL DIRECTION. THE CROSS-SECTION WAS POSITIONED ACCORDING TO THE RELATION BETWEEN THE ACTION LINE OF THE LOAD APPLIED AND THE GROWTH RINGS ORIENTATION. THE VARIATION OF MOISTURE CONTENT WAS CONSIDERED, DECREASING FROM 22 TO 12%. THE RESULTS EXPOSED A DIRECT PROPORTIONALITY BETWEEN THE INTENSITY OF THE APPLIED LOAD AND THE MECHANO-SORPTIVE STRAINS. THE VALUES DETERMINED FOR MECHANO-SORPTIVE COEFFICIENTS WERE 0.1224 AND 0.1746 GPA-1 FOR LOADS APPLIED TO RADIAL AND TANGENTIAL DIRECTIONS, RESPECTIVELY.

WOOD DRYING QUALITY AND TRANSVERSAL PERMEABILITY OF CHILEAN SECOND-GROWTH NOTHOFAGUS ALPINA (RAULÍ) WERE EVALUATED. TWO CHARGES OF RAULÍ SAWNWOOD WERE DRIED IN A EXPERIMENTAL KILN. ONE OF THE CHARGES WAS PREPARED WITH SAWNWOOD FROM PINTO THE SECOND ONE WAS PREPARED WITH SAWNWOOD FROM COLLIPULLI. THE TRANSVERSE PERMEABILITY TO AIR OF THE MATERIAL AFTER DRYING WAS DETERMINED. THE RESULTS SHOWED THAT THE DRYING RATE WAS 25% HIGHER AND DRYING TIME WAS ABOUT 18% SHORTER FOR COLLIPULLI SAWNWOOD (FROM GREEN TO 12%) DUE TO THE EXTENT OF HEARTWOOD. THE SHRINKAGE, COLLAPSE AND DRYING STRESS WERE LESS IN THE WOOD DRIED FROM COLLIPULLI, WHILE THE TRANSVERSE PERMEABILITY WAS LOWER IN THE SAMPLES FROM PINTO.

CANELO WOOD IS A HIGHLY VALUED NATIVE SPECIES IN CHILE THAT SHOWS DELICATE MARBLING PATTERNS WITH A PINKISH SOFT SILVER LUSTER. DUE TO ITS DECORATIVE QUALITIES, CANELO WOOD IS DRIED FOR THE MANUFACTURE OF FURNITURE AND MUSICAL INSTRUMENTS. HOWEVER, CANELO WOOD LACKS VESSELS CELLS THAT TYPICALLY TRANSPORT THE WATER IN HARDWOODS. PER ITS DRYING BEHAVIOR, CANELO WOOD IS CONSIDERED A TRANSITION SPECIES BETWEEN HARDWOODS AND SOFTWOODS. THEREFORE, THIS ARTICLE REPORTS DRYING SCHEDULES THAT WERE DEVELOPED FOR DRYING 25-MM AND 50-MM CANELO LUMBER. IN ADDITION, THIS ARTICLE REPORTS EXPERIMENTAL OVERALL MASS TRANSFER COEFFICIENTS, SO THAT DRYING TIMES FOR EACH OF THE DRYING STAGES CAN BE EASILY ESTIMATED.

THE EFFECT OF APPLYING CETOL AND FINISHING VARNISH PRODUCTS AND SANDING ON THE SURFACE ROUGHNESS AND COLOUR OF MARUPA (SIMAROUBA AMARA) WOOD WAS EVALUATED. THREE COATS OF EACH PRODUCT WERE APPLIED AND TWO SANDPAPER GRITS WERE USED, 280 AND 320). THE ANALYZES WERE PERFORMED ON UNTREATED SAMPLES AND BETWEEN EACH COAT OF PRODUCTS IN ORDER TO ANALYZE THE EFFECT OF SANDING, THE PRODUCTS AND THE NUMBER OF COATS. ACCORDING TO COLORIMETRY, THE L* VALUE FOR THE CONTROL TREATMENT WAS 82,83 AND THE TREATMENTS REDUCED THE L* TO 61,70 ON AVERAGE FOR THE CETOL TREATMENT AND 77,09 FOR THE VARNISH TREATMENT, SHOWING THAT THE CETOL DARKENED THE WOOD MORE THAN THE VARNISH. THE YELLOWISH AND REDDISH PIGMENTATIONS BECAME MORE INTENSE ACCORDING TO THE POSITIVE VALUES OF ?A* AND ?B*, ESPECIALLY AFTER APPLYING THE CETOL. THE TOTAL COLOUR VARIATION ?E AVERAGE WAS 40,79 FOR THE CETOL TREATMENT AND 9,83 FOR THE VARNISH TREATMENT, CONFIRMING A MUCH MORE SIGNIFICANT COLOUR CHANGE IN THE CETOL TREATMENT. SANDING WITH DIFFERENT GRITS DID NOT SIGNIFICANTLY ALTER THE SURFACE COLOUR. THE PRODUCT APPLICATION MADE THE WOOD SURFACE SMOOTHER, AND WAS NOTICEABLE FROM THE SECOND COAT. SANDING REDUCED ROUGHNESS ON THE WOOD SURFACE, BUT THE FINISHING PRODUCT WAS THE LARGEST SOURCE OF VARIATION.

THIS STUDY HAD THE OBJECTIVE TO HEAT TREATED ANGELIM VERMELHO (RED) WOOD AND THEN TO ANALYZE ITS EFFECTS ON THE PHYSICAL, MECHANICAL AND CHEMICAL PROPERTIES OF THE WOOD. THE WOOD WAS TREATED AT 180 OC AND 215 °C FOR 20 MIN AND 40 MIN IN A MUFFLE FURNACE. THE BASIC DENSITY, SHRINKAGE, ANISOTROPY, THE MODULUS OF RUPTURE AND MODULUS OF ELASTICITY, AS WELL AS THE HOLOCELLULOSE, LIGNIN, EXTRACTIVES AND ASH CONTENT VALUES WERE OBTAINED FOR THE TREATED AND UNTREATED (CONTROL) WOOD. THE RESULTS INDICATED THAT THE BASIC DENSITY WAS NOT CHANGED AND THERE WAS A DECREASE IN VOLUMETRIC SHRINKAGE IN THE MOST SEVERE TREATMENT. THE MODULUS OF RUPTURE DID NOT CHANGE AND THE CHEMICAL ANALYSIS INDICATED A DECREASE IN THE HOLOCELLULOSE AND EXTRACTIVES CONTENT RESULTING IN LIGNIN CONTENT PERCENTAGE INCREASE, MAINLY IN THE MOST SEVERE TEST.

THIS WORK ANALYZES THE IMPACT OF RADIATA PINE (PINUS RADIATA D. DON) JUVENILE WOOD ON THE PHYSICAL AND MECHANICAL PROPERTIES OF ORIENTED STRANDBOARDS (OSB). RADIATA PINE LOGS WERE OBTAINED FROM 10 TREES OF A 26-YEAR OLD MANAGED STAND LOCATED IN THE 8TH REGION OF CHILE. THE EXPERIMENTAL DESIGN CONSIDERED THE PROPORTION OF JUVENILE WOOD AND STRAND ORIENTATION AS INDEPENDENT VARIABLES. OSB PANELS OF 0.4 M×0.4 M×12 MM WERE PRODUCED AND TESTED. THE RESULTS SHOW THAT THE JUVENILE WOOD PROPORTION HAS A SIGNIFICANT IMPACT ON THE PHYSICAL AND MECHANICAL PROPERTIES OF OSB. STRANDS ORIENTATION HAD A SIGNIFICANT IMPACT ON ALL THE PROPERTIES STUDIED WITH THE EXCEPTION OF THE MODULUS OF ELASTICITY IN BENDING. HOWEVER, THIS IMPACT WAS SMALL IN ALL CASES AND WOULD NOT CHANGE PANEL GRADE WITH THE EXCEPTION OF LINEAR EXPANSION. IN THIS CASE, PANELS MADE FROM TANGENTIAL STRANDS SHOWED A HIGHER LINEAR EXPANSION. ACCORDING TO THESE RESULTS, RADIATA PINE JUVENILE WOOD CAN BE USED FOR THE MANUFACTURING OF OSB UP TO A PROPORTION OF 70% OF THE OVEN-DRY WOOD WEIGHT WITHOUT SIGNIFICANT LOSSES OF THE PHYSICAL AND MECHANICAL PROPERTIES IF THE JUVENILE WOOD STRANDS ARE LOCATED IN THE SURFACE LAYERS.

THIS STUDY DEALS WITH THE EFFECT OF HEAT TREATMENT ON PINUS OOCARPA SPECIMENS FROM FOREST PLANTATIONS IN COLOMBIA. THE EFFECTS OF TWO HEAT TREATMENTS AT 170 AND 190 °C FOR 2.5 H IN SATURATED VAPOR WERE EVALUATED BASED ON THE COLOR, DIMENSIONAL STABILITY, AIR-DRY AND BASIC DENSITIES, MODULUS OF ELASTICITY (MOE), AND MODULUS OF RUPTURE (MOR) IN STATIC BENDING OF SAMPLES. THE EVALUATIONS WERE CARRIED OUT FOLLOWING THE COLOMBIAN TECHNICAL STANDARDS NTC 290 AND 663, AND THE COLOR CHANGES RESULTING FROM HEAT TREATMENTS WERE MONITORED USING THE CIE-LAB, AS WELL AS OTHER STANDARDS FROM THE LITERATURE. THE RESULTS SHOW THAT THERE WAS 2.4% AND 3.3% MASS LOSS OF WOOD MODIFIED AT 170 AND 190 °C, RESPECTIVELY. THE AIR-DRY AND BASIC DENSITIES WERE HIGHER IN 170 °C TREATMENT THAN AFTER 190 °C TREATMENT, AND THE THERMAL MODIFICATIONS APPLIED INCREASED THE DIMENSIONAL STABILITY OF THE TREATED WOOD. AFTER TREATMENT AT 170 AND 190 °C, THE LIGHTNESS TO DARKNESS (L*) WAS REDUCED BY 10% AND 22%; THE A* COORDINATE INCREASED BY 11% AND 26%, CAUSING REDNESS IN THE TREATED WOOD; THE B* COORDINATE INCREASED BY 14% AND 17%; AND THE VALUES OF THE WOOD COLOR SATURATION (C*) INCREASED BY 14% AND 18%, RESPECTIVELY. THE GENERAL COLOR CHANGE (?E*) INCREASED GRADUALLY WITH THE INCREASE IN THE TREATMENT TEMPERATURE, RESULTING IN A HIGH COLOR CHANGE TO A VERY DIFFERENT COLOR. THE BENDING STRENGTH OF THERMALLY MODIFIED WOOD WAS IMPROVED AND SIGNIFICANTLY INCREASED TO VALUES HIGHER THAN THOSE OF UNMODIFIED PINUS OOCARPA WOOD. THE HIGH AIR-DRY AND BASIC DENSITIES, IMPROVED DIMENSIONAL STABILITY AND RESISTANCE TO BENDING, AND ATTRACTIVE APPEARANCE OF THE TREATED WOOD INDICATE THAT THERMAL MODIFICATION IS A PROMISING ALTERNATIVE FOR THE TRANSFORMATION OF PINUS OOCARPA WOOD INTO A RAW MATERIAL WITH A HIGH ADDED VALUE

TO EVALUATE EVOLUTION OF PHYSICAL AND MECHANICAL PROPERTIES DUE TO DRYING AND HEAT MODIFICATION, A LOAD OF RADIATA PINE WOOD WAS SELECTED AND PROPERTIES WERE MEASURED AFTER EACH DRYING PROCESS. THE RESULTS REVEALED INTERESTING CORRELATIONS BETWEEN INTRINSIC FACTORS AND PROPERTIES; THE VALUES OF DENSITY WERE HIGHLY DISPERSED AFTER DRYING OR THERMAL TREATMENT AND UNCORRELATED WITH OTHER PARAMETERS, BUT THE MINIMUM DENSITY VALUES WERE KEPT CONSTANT AFTER HEAT TREATMENT. MOREOVER, WEIGHT LOSS (WL) AND MOISTURE CONTENT (MC) WERE DECREASING PROPORTIONALLY TO THE TREATMENT INTENSITY, DUE TO WOOD?WATER INTERACTIONS, CELL WALL CHANGES, AND THERMAL DEGRADATION OF WOOD FRACTIONS. WL AND MC WERE REASONABLY CORRELATED WITH THE DIMENSIONAL STABILITY, IMPROVING THE DIMENSIONAL STABILITY AFTER DRYING TREATMENTS, BUT KEEPING THE SAME ORDER OF ANISOTROPY. REGARDING THE WOOD STIFFNESS (MODULUS OF ELASTICITY, MOE), IT WAS UNAFFECTED BY THE DRYING TEMPERATURE, AND THE CORRELATIONS BETWEEN MOE AND MC OR WL APPEAR TO BE ACCEPTABLE, AND THE VALUES OF MC OR WL DID NOT ADVERSELY AFFECT THE MOE. HOWEVER, THE MODULUS OF RUPTURE WAS DROPPED DURING THE DRYING PROCESS, OBTAINING THREE DIFFERENTIATED GROUPS WITH A DECREASE IN AROUND 59% AFTER THERMAL MODIFICATION.

THIS ARTICLE REPORTS THE RESULTS OF AN EXPLORATORY STUDY DESIGNED TO REDUCE HEAT AND ELECTRICITY CONSUMPTION IN INDUSTRIAL DRYING OF RADIATA PINE. THE EXPERIMENTS WERE PERFORMED WITH SLIGHT MODIFICATIONS OF THE STANDARD DRYING SCHEDULES USED BY THE SAWMILL TO DRY RADIATA PINE IN 100-M3 INDUSTRIAL KILNS. THE HEAT AND ELECTRICITY CONSUMPTION WERE DETERMINED WITH DATA COLLECTED DURING THE DRYING RUNS AND CALCULATIONS BASED ON MATHEMATICAL MODELS. THE RESULTS SHOWED THAT DEPENDING ON THE CASE, HEAT AND POWER CONSUMPTION WERE RESPECTIVELY REDUCED BY UP TO 14 AND 35%.

SE ESTUDIA LA CINÉTICA DEL SECADO CONVENCIONAL Y BAJO VACÍO DE PINO RADIATA (PINUS RADIATA D. DON). SE ANALIZA LA EVOLUCIÓN DE LA HUMEDAD DE LA MADERA DURANTE EL SECADO CONVENCIONAL BASÁNDOSE EN EL CÁLCULO DE UN COEFICIENTE GLOBAL DE SECADO. BAJO VACÍO SE EXPLORA LA VELOCIDAD DEL SECADO APOYÁNDOSE EN LA DETERMINACIÓN DE UNA CURVA CARACTERÍSTICA. LA MADERA UTILIZADA EN LOS EXPERIMENTOS ES RECOGIDA AL AZAR Y RECIÉN ASERRADA EN UNA PLANTA INDUSTRIAL DE LA OCTAVA REGIÓN, CHILE. SE REALIZAN TRES ENSAYOS DE SECADO CONVENCIONAL UTILIZANDO UN PROGRAMA CON CONDICIONES AMBIENTALES CONSTANTES 70/60 (ºC/ºC) Y UN ENSAYO DE SECADO BAJO VACÍO CON TEMPERATURA AMBIENTE DE 70 (ºC), HUMEDAD DE EQUILIBRIO DE LA MADERA IGUAL A 9 (%) Y UN NIVEL DE VACÍO DE 20 %. MEDICIONES EXPERIMENTALES DE LA EVOLUCIÓN DE LA MASA Y LA TEMPERATURA DEL AIRE Y DE LA MADERA SON RECOGIDAS DURANTE EL TRANSCURSO DE TODOS LOS ENSAYOS DE SECADO. LOS RESULTADOS MUESTRAN QUE DURANTE EL SECADO CONVENCIONAL DE PINO RADIATA, LA EVOLUCIÓN DE LA HUMEDAD DE LA MADERA PUEDE SER REPRESENTADA SATISFACTORIAMENTE CON UN COEFICIENTE GLOBAL DE SECADO DE 6.5*10-5 (KG/M2.S). DURANTE EL SECADO BAJO VACÍO DEL PINO RADIATA, LA CURVA CARACTERÍSTICA PRESENTA UNA ETAPA INICIAL DE SECADO CONSTANTE DE 11 HORAS, UN CONTENIDO DE HUMEDAD CRÍTICO DE 58 (%) Y UNA VELOCIDAD DE SECADO MÁXIMA DE 1.45 (%/H).

ACACIA MELANOXYLON AND ACACIA DEALBATA ARE TWO AUSTRALIAN SPECIES WELL ACCLIMATED IN CHILE, BOTH WOOD SPECIES WITH AN INTERESTING INDUSTRIAL POTENTIAL. IN THIS WORK, HAS BEEN STUDIED KILN DRYING RUNS AND THE WOOD DRYING QUALITY OF THE SAWN WOOD OF ACACIA MELANOXYLON AND ACACIA DEALBATA DURING KILN DRYING AT CONVENTIONAL TEMPERATURES. EIGHT TESTS OF KILN DRYING TO CONVENTIONAL TEMPERATURES ARE MADE, USING A CONVECTIVE DRYING OF 0,3 M3 OF CAPACITY. THE EXPERIMENTAL DESIGN INCLUDES AS VARIABLE THE SPECIES (A. MELANOXYLON AN A. DEALBATA), THE WOOD THICKNESS (25 AND 50 MM) AND THE CUT-TYPE (FLATSAWN-WOOD AND QUARTERSAWN-WOOD). THE WOOD DRYING QUALITY ON THE BASIS OF EUROPEAN AND CHILEAN STANDARDS IS EVALUATED. THE RESULTS SHOW THAT FOR A SAME THICKNESS, BOTH SPECIES A. MELANOXYLON AND A. DEALBATA, IN FLATSAWN AND QUARTERSAWN-WOOD COULD BE SATISFACTORILY KILN DRYIED UNDER A SIMILAR PROGRAM OF CONVENTIONAL TEMPERATURES. THE WOOD DRYING QUALITY IS PERFORMED DUE TO BOTH SPECIES ARE FREE OF COLLAPSE AND THEY ARE AN LOW TRANSVERSAL SHRINKAGE.

QUINCE AÑOS PARA UNA REVISTA CIENTÍFICA ES UNA EDAD QUE ESTIMO PUEDE SER CONSIDERADA COMO EQUIVALENTE A LA EVOLUCIÓN DE LA INFANCIA A LA ADOLESCENCIA. LAS CAPACIDADES APREHENDIDAS DURANTE LA INFANCIA YA QUEDARON INSTALADAS PARA DESARROLLARSE EN ESTA NUEVA ETAPA.

COLLAPSE AND DRYING STRESSES ARE CURRENTLY INDUCED DURING THE DRYING OF EUCALYPTUS NITENS IN SOLID WOOD PRODUCTS. THE PURPOSE OF THIS STUDY WAS TO INVESTIGATE THESE DRYING STRESSES BY MEASURING HYGROMECHANICAL STRAINS DURING THE DRYING OF EUCALYPTUS NITENS BOARDS. SMALL SAMPLES OF EUCALYPTUS NITENS WOOD WERE ORIENTED IN THE RADIAL AND TANGENTIAL DIRECTIONS AND TESTED TO DETERMINE THE HYGROMECHANICAL STRAINS DURING THE DRYING PROCESS. THIS EXPERIMENTAL WORK CONSISTED OF CANTILEVERED BENDING TESTS CONDUCTED UNDER VARIABLE RELATIVE HUMIDITY CONDITIONS. TESTS WERE PERFORMED IN A CONDITIONING CHAMBER AT 30 °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