NANOINDENTATION IS A POWERFUL TOOL FOR HARDNESS TESTING ON A VERY SMALL SCALE. SINCE THE TECHNIQUE WAS FIRST INTRODUCED FOR STUDYING WOOD CELL WALL MECHANICS, IT HAS BEEN INTEGRATED AS AN IMPORTANT TOOL FOR MEASURING THE MODULUS OF ELASTICITY AND HARDNESS OF WOOD CELL WALLS. IN THIS STUDY, HARDNESS MEASURED WITH NANOINDENTATION (NANOHARDNESS) WAS COMPARED WITH HARDNESS MEASURED BY THE STANDARD BRINELL TEST METHOD (BRINELL HARDNESS) ON JACK PINE (PINUS BANKSIANA LAMB.) WOOD. NANOINDENTATION WAS PERFORMED ON BOTH THE S2 LAYER OF THE SECONDARY CELL WALL AND THE MIDDLE LAMELLA (ML) OF EARLY- AND LATEWOOD FIBERS. FOUR ANNUAL GROWTH RINGS WERE STUDIED. THE INFLUENCE OF GROWTH RING AND INITIAL SPACING ON BOTH MEASUREMENTS WAS ANALYZED. THE RELATIONSHIP BETWEEN BRINELL HARDNESS, NANOINDENTATION MEASUREMENTS, AND AVERAGE RING DENSITY WAS ALSO STUDIED. RESULTS SUGGEST THAT BRINELL- AND NANOHARDNESS ARE CONTROLLED BY DIFFERENT MECHANISMS AND FACTORS. THE LOCATION OF NANOHARDNESS MEASUREMENTS (I.E., S2 LAYER OR ML) ALSO INFLUENCED HARDNESS DIFFERENTLY. IT WAS CONCLUDED THAT NANOMEASUREMENTS ARE NOT AN EXACT REPRESENTATION OF WOOD MECHANICAL PROPERTIES CONDUCTED AT THE MACRO LEVEL BECAUSE OF THE HIERARCHICAL STRUCTURE OF WOOD. THE EFFECT OF OTHER FACTORS SUCH AS MOISTURE OR WOOD EXTRACTIVE CONTENT MAY ALSO NEED CONSIDERATION.

WOOD MATERIAL HAS A THERMO-HYGROMECHANICAL BEHAVIOUR BECAUSE ITS DEFORMATION DEPENDS ON THE COMBINED ACTION OF TEMPERATURE, RELATIVE HUMIDITY AND MECHANICAL LOAD VARIATIONS. STRESS-LAMINATED TIMBER BRIDGE DECK SHOW A REDUCTION OF STRESS IN THE TENSION BARS MAINLY DUE TO THE RELAXATION AND SHRINKAGE OF WOOD, INCREASING WITH MOISTURE CONTENT AND TEMPERATURE CHANGES WITHIN THE WOOD. THE AIM OF THIS RESEARCH WAS TO STUDY THE RHEOLOGICAL BEHAVIOR OF STRESS-LAMINATED TIMBER BRIDGE DECK SAMPLES UNDER TEMPERATURE AND RELATIVE HUMIDITY VARIATIONS. A TOTAL OF 16 SAMPLES WERE PREVIOUSLY TREATED WITH FOUR TYPES OF PRESERVATIVE TREATMENTS, WHICH WERE SUBJECTED TO FOUR CYCLES OF TEMPERATURE AND RELATIVE HUMIDITY IN A CLIMATE CHAMBER. WOOD SAMPLES DEFORMATION AND STRESS IN THE STEEL BARS WERE MEASURED. THE RESULTS SHOWED A SIGNIFICANT STRESS REDUCTION IN THE STEEL BAR DURING THE SUMMER SEASON AND A SIGNIFICANT INCREASE DURING THE WINTER SEASON. THE RESULTS ALSO SHOWED SIGNIFICANT DIFFERENCES BETWEEN THE DEFORMATIONS OF CONTROL SAMPLES COMPARED TO THE PRESERVATIVE TREATED SAMPLES FOR EACH CYCLE. HOWEVER, FOR INTERLAMINAR STRESS, DIFFERENCES WERE SIGNIFICANT ONLY IN THE WINTER SEASON. MOREOVER, FOR BOTH DEFORMATION AND INTERLAMINAR STRESS, NO SIGNIFICANT DIFFERENCES BETWEEN CYCLES THREE AND FOUR WERE FOUND. THEREFORE THERE IS NO EVIDENCE OF THERMO-HYGROMECHANICAL CREEP OR RELAXATION OF WOOD IN THE CONDITIONS CONSIDERED IN THIS STUDY.

IN THE LAST YEARS, CHILE HAS INCREASED THE PRODUCTION OF BLUEBERRIES; CONSEQUENTLY, A LARGE NUMBER OF LIGNOCELLULOSIC RESIDUES DERIVED FROM THE HARVESTING AND PRUNING ARE BEING GENERATED. THESE RESIDUES ARE COMMONLY BURNED, THEREFORE INCREASING CO2 EMISSIONS. THIS STUDY FOCUSES ON THE EXTRACTION OF TWO ADDED-VALUE PRODUCTS FROM BLUEBERRY PRUNING RESIDUES (BPRS), CELLULOSE NANOCRYSTALS (CNC-IL) ISOLATED USING IONIC LIQUID (IL) 1-ETHYL-3-METHYLIMIDAZOLIUM [EMIM][CL], AND CARBOXYLATED NANOCELLULOSE (TOCNC), ISOLATED WITH (2,2,6,6-TETRAMETHYLPIPERIDINE-1-YL) OXYL OR TEMPO REAGENT COMBINED WITH A MECHANICAL DISINTEGRATION PROCESS. THESE PRODUCTS WERE CHARACTERIZED BY ZETA POTENTIAL (?), FTIR, XRD, TGA, AFM, AND CONDUCTOMETRIC TITRATION. RESULTS SHOW OVAL-SHAPED CNC-IL PARTICLES WITH LENGTHS OF 46.1?±?9.3?NM; MEANWHILE, TOCNC WERE ROD-LIKE SHAPED PARTICLES, WITH LENGTHS OF 120.3?±?30.6?NM. THESE BPRS SHOWED A PROMISING POTENTIAL TO PRODUCE CELLULOSE NANOCRYSTALS (CNCS) WITH DIFFERENT SURFACE PROPERTIES, OPENING A NEW ALTERNATIVE FOR THE PRODUCTION OF CELLULOSE NANOMATERIALS (CNMS) WITH PROMISING APPLICATIONS IN COLLOIDAL FORMULATIONS, COATINGS, AMONG OTHERS.

THE AIM OF THIS STUDY WAS TO DENE THE MINIMUM VOLUMEN IN TREES OF E. NITENS THAT CHARACTERIZE THE MECHANICAL AND ANATOMY BEHAVIOR FOR NON-DESTRUCTIVE SAMPLING. E TREES WERE CUT FROM SITES LOCATED IN MULCHEN AND YUNGAY IN THE REGION OF BÍO BÍO. RELATIONSHIPS WERE FOUND BETWEEN NANO-MECHANICAL PROPERTIES, WOOD ANATOMY AND WOOD CRACKS AND FRACTURES. E RESPONSE VARIABLES WERE THE DUCTILITY RATIO (E/H) AND THE MODULUS OF RESILIENCE (UR), IN THE S2 LAYER AND MIDDLE LAMELLA. E RESULTS SHOWED THAT THE REPRESENTATIVE VOLUME, FROM E. NITENS FAMILIES IS AT 3 METER HIGH FROM BASE OF THE TREES AND BETWEEN THE 5TH TO 7TH ANNUAL RINGS. ALSO, IT WAS ESTABLISHED THAT THE MIDDLE LAMELLA IS MORE BRITTLE THAN THE S2 LAYER. RELATIONSHIP BETWEEN THE VESSELS MORPHOLOGY AND THE LEVEL OF THE WOOD CRACKING WAS OBSERVED. A HIGH AREA OF VESSELS, A HIGH VESSEL DIAMETER AND A SMALL FREQUENCY OF THEM, RESULTED IN HIGH CRACKING. E CRACKS WERE MAINLY CONCENTRATED IN THERST METERS OF TREE, WERE WE FOUND A GOOD RELATIONSHIP OF THIS RESPONSE VARIABLE WITH THE E/H RATIO FOR THE MIDDLE LAMELLA; THERE WAS A SIGNICANT CHANGE OF THIS RATIO AT 3 METERS HIGH. CRACKS WERE EVIDENT ON EARLYWOOD AND FROM

CHILE IS THE SECOND LARGEST GLOBAL PRODUCER OF BLUEBERRIES, WHICH ARE HARVESTED IN THE SOUTH-CENTRAL REGION. AS A RESULT OF THE EXPONENTIAL PRODUCTION GROWTH, A LARGE AMOUNT OF LIGNOCELLULOSIC BIOMASS IS GENERATED FROM PRUNING AND LEFT ON THE GROUND AS WASTE. AS AN ALTERNATIVE TO THE CURRENT INCINERATION PRACTICES AND THEIR NEGATIVE AIR POLLUTION EFFECTS, THIS STUDY PROPOSED VALUE-ADDED UTILIZATION OF THESE AGROINDUSTRY RESIDUES. THE CHEMICAL COMPOSITIONS (CELLULOSE, HEMICELLULOSE, LIGNIN, EXTRACTIVES, AND ASH) OF THE PRUNING RESIDUES FROM BLUEBERRY BRANCHES AND TRUNKS WERE ANALYZED. THE CELLULOSE CONTENTS FROM THE BRANCHES AND TRUNKS WERE SIMILAR AT 52% AND 51%, RESPECTIVELY. HOWEVER, THE X-RAY DIFFRACTION ANALYSIS INDICATED IMPORTANT DIFFERENCES IN THEIR CRYSTALLINITY INDEX, WITH 52% AND 84%, RESPECTIVELY. COMPARED WITH THE CELLULOSE OBTAINED FROM THE TRUNKS, CELLULOSE FROM THE BRANCHES WAS LESS THERMALLY STABLE, POSSIBLY DUE TO THE PRESENCE OF RESIDUAL LIGNIN AND HEMICELLULOSE. ACCORDING TO THE RESULTS, IT IS EXPECTED THAT THE AGRO-INDUSTRIAL RESIDUES FROM PRUNING OF THE CHILEAN BLUEBERRY BUSHES (BRANCHES AND TRUNKS) MIGHT BE OF USE AS A POTENTIAL PLATFORM FOR BIOPRODUCTS, SUCH AS CELLULOSE MATERIALS IN ORDER TO REPLACE SYNTHETIC OR UNSUSTAINABLE MATERIALS.

DENSIFICATION OF WOOD LEADS TO IMPROVEMENT OF ITS MECHANICAL PROPERTIES. SPECIMENS OF PINUS RADIATA AND EUCALYPTUS NITENS WOOD WERE DENSIFIED USING HEAT, STEAM, AND PRESSURE TO IMPROVE THEIR MECHANICAL PROPERTIES AND THUS ENHANCE THEIR UTILIZATION. AT A MAXIMUM STEAM PRESSURE OF 550 KPA AND A MAXIMUM PRESS HYDRAULIC PRESSURE RANGING FROM 4.5 TO 9 MPA, SELECTED TEMPERATURES OF 160°C, 180°C, AND 200°C WERE USED TO CHECK THE MECHANICAL PROPERTIES AND TO IDENTIFY THE CHEMICAL COMPOSITION OF WOOD SAMPLES BEFORE AND AFTER DENSIFICA-TION. DENSIFIED WOOD SAMPLES SHOWED MARKEDLY REDUCED HYGROSCOPICITY. THE CHEMICAL CHANGES IN THE WOOD CONSTITUENTS OCCURRING DURING DENSIFICATION WERE CHARACTERIZED USING FT-IR, PY-GC/MS, AND XPS. ACCORDING TO THE DENSIFICATION PROCESS BETWEEN PINE AND EUCALYPTUS, THE RESULTS OBTAINED SHOWED THAT THE DENSIFICATION EFFECTS WERE BETTER FOR EUCALYPTUS NITENS THAN FOR PINUS RADIATA. THE FT-IR ANALYSIS REVEALED A HIGH CONDENSATION INDEX FOR PINE LIGNIN AND THE LOW CONDENSATION INDEX FOR EUCALYPTUS LIGNIN, INDICATING EASIER FORMATION OF CC LINKAGES BY DENSIFICATION IN PINE LIGNIN. PY-GC/MS ANALYSES WERE PERFORMED TO FOLLOW THE LIGNIN/CARBOHYDRATE RATIO, AND THESE REVEALED MAJOR CARBOHYDRATE LOSSES DURING DENSIFICATION AT THE HIGHEST TEMPERATURE.

COMPRESSION UNDER THE EFFECT OF HEAT AND STEAM, ALSO CALLED THERMO-HYGROMECHANICAL (THM) DENSIFICATION, CAN INCREASE WOOD DENSITY AND THEREFORE IMPROVE ITS STRENGTH, STIFFNESS, AND HARDNESS. OIL-HEAT TREATMENT (OHT) IS ALSO KNOWN TO REDUCE WOOD?S HYGROSCOPICITY AND IMPROVE DIMENSIONAL STABILITY. A COMBINATION OF BOTH TREATMENTS CAN THEREFORE PRODUCE WOOD WITH IMPROVED MECHANICAL PROPERTIES AND DIMENSIONAL STABILITY. THE OBJECTIVE OF THIS PROJECT WAS TO DETERMINE CELL WALL MECHANICAL PROPERTIES OF THM-DENSIFIED AND OHT WOOD. TREMBLING ASPEN VENEERS WERE DENSIFIED BY A THM PROCESS AND SUBSEQUENTLY TREATED IN CANOLA OIL AT 200 AND 220°C. NANOINDENTATIONS WERE PERFORMED IN EARLYWOOD CELL WALLS. THE RESULTS SHOW THAT CELL WALL LONGITUDINAL MODULUS OF ELASTICITY INCREASED SIGNIFICANTLY FROM 13.5 GPA FOR THE CONTROL TO A MAXIMUM OF 18.2 GPA FOR THM DENSIFIED WOOD WITH OR WITHOUT OHT. CELL WALL HARDNESS INCREASED FROM 0.27 GPA TO A MAXIMUM OF 0.43 GPA. BOTH THM DENSIFICATION AND OHT SIGNIFICANTLY INCREASED CELL WALL HARDNESS. THEREFORE, THE INCREASE IN MECHANICAL PROPERTIES OF THM-DENSIFIED AND OHT WOOD CAN BE DUE TO AN INCREASE IN WOOD DENSITY RESULTING FROM A REDUCTION IN POROSITY BUT ALSO TO AN INCREASE IN THE MECHANICAL PROPERTIES OF THE CELL WALL.

THE WORK DEVELOPED BY AN INTERDISCIPLINARY TEAM OF PROFESSIONALS FROM THE BIOBÍO REGION OF CHILE, IN THE CONTEXT OF A GLOBAL HEALTH EMERGENCY CAUSED BY THE SARS-COV-2 VIRUS IS PRESENTED. THE OBJECTIVE WAS TO DESIGN, MANUFACTURE AND DISTRIBUTE A FACIAL BARRIER IN RESPONSE TO THE LACK OF PERSONAL PROTECTIVE EQUIPMENT (PPE) IN THE HEALTH SECTOR. THE PERIODS OF CONFINEMENT RESULTED IN DIFFICULTIES IN ACCESSING ESSENTIAL PPE, DUE TO TRANSPORT LOGISTICS ALTERATIONS AND INCREASED DEMAND. TO DELIVER SOLUTIONS, THE COORDINATED ACTION OF PROFESSIONALS, TECHNOLOGICAL CAPABILITIES AND AVAILABLE MATERIALS WAS ESSENTIAL. THE METHODOLOGY ADDRESSES STAGES OF IDENTIFICATION OF NEEDS FOR PSYCHOLOGICAL AND PHYSICAL COMFORT OF HEALTH PERSONNEL, BASED ON THEIR EXPERIENCE OF USING FACIAL BARRIERS; IDENTIFICATION OF NATIONAL REGULATIONS FOR PPE; IDENTIFICATION OF THE MATERIAL AND TECHNOLOGICAL RESOURCES AVAILABLE IN THE REGION FOR THE DESIGN AND MANUFACTURE OF FACIAL BARRIERS; IDEATION PROCESS IN THE DESIGN RESEARCH LABORATORY OF THE UNIVERSIDAD DEL BÍO-BÍO; VALIDATION WITH USERS; LABORATORY VALIDATION; DISINFECTION AND DISTRIBUTION. THE RESULTS SHOW ASPECTS OF USER PERCEPTION WITH RESPECT TO TWO PROTOTYPES. RESULTS OF LABORATORY TESTS IN ACCORDANCE WITH CURRENT REGULATIONS CONTRIBUTE TO KNOW THE PROTECTION BENEFITS OF THE FINAL PROPOSAL. THE DISCUSSION REFERS TO THE INTERDISCIPLINARY CONTRIBUTION, THE INTEGRATION OF THE USER IN THE DESIGN PROCESS AND A PROSPECTIVE APPROACH. THE CONCLUSIONS PRESENT A REFLECTION ON THE EXPERIENCE DEVELOPED TO DELIVER EFFECTIVE RESPONSES IN COMPLEX TIMES.

THE AIM OF THIS STUDY WAS TO DEFINE A REPRESENTATIVE VOLUME ELEMENT TO CHARACTERIZE THE MECHANICAL PROPERTIES OF STRESS-LAMINATED DECK SPECIMENS OF RADIATA PINE AND EUCALYPTUS NITENS. THE DETERMINATION OF THE REPRESENTATIVE VOLUME ELEMENT ALLOWED TO IDENTIFY THE SMALLEST REPRESENTATIVE SECTION OF THE STRESS-LAMINATED DECK. FOR THIS, THE NANOMECHANICAL PROPERTIES OF THE CELL WALLS AND MIDDLE LAMELLAS WERE DETERMINED BY NANOINDENTATIONS. THIS STUDY WAS CONDUCTED IN TWO PHASES. IN THE FIRST PHASE, THE GROWTH RING REPRESENTATIVE OF THE PIECES OF WOOD UNDER COMPRESSION PERPENDICULAR TO THE GRAIN WAS DETERMINED. IN THE SECOND PHASE, THE BOARD REPRESENTATIVE OF THE STRESS-LAMINATED DECK SPECIMENS SUBJECTED TO LONG-TERM COMPRESSION LOADS AND VARIABLE ENVIRONMENTAL CONDITIONS WAS DETERMINED. THE RESULTS OBTAINED IN THE FIRST PHASE OF THE STUDY SHOWED THAT THERE WAS NO SPECIFIC TENDENCY OF THE NANOMECHANICAL PROPERTIES THROUGH GROWTH RINGS IN THE CROSS-SECTION OF PINUS RADIATA AND EUCALYPTUS NITENS SPECIMENS SUBJECTED TO COMPRESSION LOADS PERPENDICULAR TO THE GRAIN. IN THE SECOND PHASE OF THE STUDY, IT WAS FOUND THAT LONG-TERM COMPRESSION LOADS IN STRESS-LAMINATED DECK SPECIMENS MAINLY AFFECT THE MECHANICAL PROPERTIES OF THE CELLULAR STRUCTURE OF EXTERIOR AND CENTRAL BOARDS. FINALLY, THE REPRESENTATIVE VOLUME ELEMENT IN A STRESS-LAMINATED DECK SPECIMEN WAS FOUND IN THE EARLYWOOD OF THE GROWTH RING FARTHEST TO THE PITH IN THE CROSS SECTION OF THE CENTRAL BOARD.

THE OBJECTIVES OF THIS STUDY WERE TO EVALUATE THE EFFECT OF KNIFE WEAR ON THE GLUABILITY OF PLANED SURFACES OF RADIATA PINE. A CONVENTIONAL PROCESS WAS USED TO PLANE SAMPLES TO FOUR LENGTHS: 200; 10,000; 20,000; AND 30,000 M. CUTTING-EDGE RECESSION WAS MEASURED ON THE CLEARANCE SURFACE OF THE PLANING KNIFE FOR EACH LENGTH. THE GLUING PROPERTIES OF THE PLANED SURFACES WERE DETERMINED FOR EACH OF THE FOUR LEVELS OF KNIFE WEAR USING POLYVINYL ACETATE AND EMULSION POLYMER ISOCYANATE ADHESIVES. THE RESULTS SHOWED THAT THE GREATEST AMOUNT OF CUTTING-EDGE RECESSION ON THE CLEARANCE SURFACE WAS 65 MM AFTER 30,000 M OF PLANING. THE TENSILE SHEAR STRENGTH (TSS) OF THE LAP-JOINT GLUE LINE DECREASED WITH KNIFE WEAR FROM INCREASED PLANING. HOWEVER, TSS WAS GENERALLY GREATER THAN THE MINIMUM PRESCRIBED BY THE BS EN 204 STANDARD. THE EFFECT OF KNIFE WEAR ON TSS WAS MORE SIGNIFICANT AFTER ACCELERATED AGING OF THE GLUED SAMPLES.

THE OBJECTIVE OF THIS STUDY WAS TO EVALUATE AND CORRELATE AT MACROSCALE THE THERMO-HYGROMECHANICAL EFFECT OF ON THE NANOMECHANICAL PROPERTIES OF PINUS RADIATA D. DON AND EUCALYPTUS NITENS(DEANE & MAIDEN)EVALUATED IN THE S2 LAYER OF THE CELL WALL AND IN THE MIDDLE LAMELLA OF SPECIMENS UNDER COMPRESSION PERPENDICULAR TO GRAIN AND UNDER CYCLIC ENVIRONMENTAL CONDITIONS. AT MACROSCALE, 4 STRESSLAMINATED DECK SPECIMENS WITHOUT PRESERVATIVE TREATMENT WERE STUDIED FOR BOTH SPECIES AND 4 DECK SPECIMENS OF RADIATA PINE TREATED WITH CREOSOTE. THE NANOMECHANICAL PROPERTIES OF THE CELLULAR STRUCTURE WERE DETERMINED USING NANOINDENTATIONS. THE RESULTS SHOWED THAT THE THERMO-HYGROMECHANICAL EFFECT AT MACROSCALE INDUCED A SIGNIFICANT INCREASE OF ELASTIC MODULUS AND HARDNESS OF THE CELLULAR STRUCTURE DURING THE SUMMER SEASON AND DURING THE SECOND ENVIRONMENTAL CYCLE, WITH RESPECT TO THE WINTER SEASON AND THE FIRST CYCLE. ON THE OTHER HAND, IT WAS SHOWN THAT THE APPLICATION OF LONG-TERM COMPRESSIVE LOADS LEAD TO A SIGNIFICANT DECREASE OF THE ELASTIC MODULUS AND HARDNESS OF THE CELLULAR STRUCTURE OF WOOD AND AN INCREASE IN THE RELAXATION FACTOR, COMPARED TO THE PIECES SUBMITTED TO FREE DEFORMATION.

EFFICIENCY OF FINGER-JOINTS IN THE ENGINEERED WOOD PRODUCTS IS KEY TO THE TO THE PERFORMANCE OF THESE PRODUCTS. THE AIM OF THIS RESEARCH WORK WAS TO EVALUATE, BY SCANNING MICROSCOPIC ANALYSIS, THE EFFECT OF END PRESSURE ON THE PERFORMANCE OF HORIZONTAL FINGER-JOINT OF BLACK SPRUCE (PICEAMARIANA (MILL.) B.S.P) SPECIMENS. A FEATHER JOINT CONFIGURATION GLUED WITH AN ISOCYANATE TYPE OF ADHESIVE CURED AT ROOM-TEMPERATURE WAS USED. THE FINGER-JOINTS WERE MACHINED AT A FEED RATE OF 18.3 M/MIN, ROTATIONAL SPEED OF 3500 RPM, AND AT A FEED PER KNIFE (CHIP-LOAD) OF 0.86 MM. A SINGLE-FACE GLUELINE APPLICATION WAS USED AT A SPREAD RATE OF 110 G/M2. THE CURING TIME WAS KEPT AT 24 HOURS. SIX END-PRESSURE LEVELS RANGING FROM 1.38 MPA TO 4.82 MPA APPLIED FOR 20 SECONDS WERE INVESTIGATED. RESULTS SHOWED THAT CELL DEPTH DAMAGE INCREASED AS END-PRESSURE INCREASED. JOINTS ALSO SHOWED FORMATION OF SOME AIR BUBBLES WITHIN THE GLUELINE WHICH LEAD TO A REDUCTION IN THEIR TENSILE STRENGTH.

THIS STUDY WAS CONDUCTED TO INVESTIGATE THE CAUSES AND POSIBLES FACTORS RELATED TO FRACTURES IN THE CELLULAR STRUCTURE IN EUCALYPTUS NITENS. NANOMECHANICAL CELL WALL PROPERTIES AT THE MIDDLE LAMELLA LEVEL (ML), S1 AND S2 LAYERS WERE EVALUATED. IN ADDITION, THE AREA, AND DIAMETER OF VESSELS WERE MEASURED. THESE PARAMETERS WERE ASSOCIATED WITH EXTREME LEVELS OF CRACKING (HIGH AND LOW) IN TWO EUCALYPTUS NITENS FAMILIES. THE SAMPLES WERE TAKED FROM TWO SITES OF THE 8TH REGION OF CHILE. THE ANALYSIS OF THE DUCTILITY RATIO (E/H) DEMONSTRATED THAT THE ML IS MORE BRITTLE THAN THE S1 LAYER; AND THE S1 IS MORE BRITTLE THAN S2 LAYER. THE ML AND S1 LAYER BEHAVE LIKE RESILIENT MATERIALS, BUT NOT THE S2 LAYER. THE DIFFERENCE IN THE MODULUS OF RESILIENCE WAS RELATED TO HIGHER SHEAR STRESSES AT THE ML/S2 AND AT S1/S2 INTERFACES. THE CHARACTERIZATION OF THE VESSELS SHOWED THAT THE FAMILIES WITH GREATER LEVEL OF CRACKING HAVE ALSO LOWER FREQUENCY AND GREATER AREA AND DIAMETER OF VESSELS THE S1 LAYER WAS WEAKER TAN S2 LAYER AND LM DUE TO THEIR DIFFERENCE IN RESISTANCE BETWEEN THEM AND COMBINED WITH THE INTERNAL STRESSES MIGHT PROPAGATE THE MICROCRACKS.

THE THERMO-HYGROMECHANICAL DENSIFICATION PROCESS CHANGES THE CHEMICAL COMPOSITION AND THE PHYSICAL AND MECHANICAL PROPERTIES OF WOOD. THE AIM OF THIS WORK WAS TO STUDY THE IMPACT OF THE CHEMICAL COMPOSITION OF PINUS RADIATA WOOD ON ITS PHYSICAL AND MECHANICAL PROPERTIES FOLLOWING THE THERMO-HYGROMECHANICAL DENSIFICATION PROCESS. THE SAMPLES WERE INITIALLY SEGREGATED BY LIGNIN CONTENT. DENSITY, HARDNESS, MODULUS OF ELASTICITY (MOE), AND MODULUS OF RUPTURE (MOR), IN ADDITION TO LIGNIN, ?-CELLULOSE, HEMICELLULOSE, AND EXTRACTIVE CONTENTS, WERE DETERMINED BEFORE AND AFTER THE DENSIFICATION PROCESS. THE RESULTS INDICATED THAT DENSIFIED WOOD WITH HIGH INITIAL LIGNIN CONTENT HAD GREATER RATE OF INCREASES IN DENSITY AND MOE THAN WOOD WITH LOWER INITIAL LIGNIN CONTENT. ADDITIONALLY, DENSIFIED WOOD WITH LOWER INITIAL LIGNIN CONTENT HAD GREATER RATE OF INCREASES IN HARDNESS. THE RATE OF INCREASE OF MOR DID NOT SHOW SIGNIFICANT DIFFERENCES WITHIN BOTH GROUPS. CARBOHYDRATES PRESENT IN THE CONTROL AND THE DENSIFIED WOOD PLAYED AN IMPORTANT ROLE IN THE MECHANICAL STRENGTH OF THE FINAL PRODUCT.

THE WOOD-BASED PANEL INDUSTRY GENERATES A SIGNIFICANT AMOUNT OF SOLID RESIDUES IN ITS PRODUCTION ACTIVITIES, INCLUDING MEDIUM-DENSITY FIBERBOARD (MDF) MOLDING MANUFACTURING. THESE RESIDUES CONSIST OF FINE FIBERS MEASURING BETWEEN 0.15 MM AND 1.19 MM IN LENGTH. A LARGE PROPORTION OF THEM CURRENTLY NEEDS TO BE UTILIZED, MAINLY DUE TO THE PROBLEM OF EXCESSIVE ACCUMULATION. THEY CAN BE REUSED AS RAW MATERIAL FOR MANUFACTURING NEW PRODUCTS BY ADOPTING A CIRCULAR ECONOMY APPROACH. THEIR THERMAL PROPERTIES CAN ALSO BE ENHANCED BY IMPREGNATING THEM WITH PHASE CHANGE MATERIALS (PCMS). THIS RESEARCH AIMS TO DEVELOP A PROCESS FOR IMPREGNATING MDF PANEL RESIDUES (R) WITH PCMS TO OBTAIN SHAPE-STABILIZED COMPOUNDS CAPABLE OF STORING THERMAL ENERGY. THREE DIFFERENT COMMERCIALLY AVAILABLE PCMS WERE USED. THEY WERE INCORPORATED IN THE MDF RESIDUES BY VACUUM IMPREGNATION. THE MORPHOLOGY, CHEMICAL STRUCTURE, THERMAL STABILITY, AND PHASE CHANGE PROPERTIES OF THE COMPOUNDS OBTAINED WERE STUDIED BY SCANNING ELECTRON MICROSCOPY (SEM), FOURIER-TRANSFORM INFRARED (FTIR) SPECTROMETRY, THERMOGRAVIMETRIC ANALYSIS (TGA), AND DIFFERENTIAL SCANNING CALORIMETRY (DSC), RESPECTIVELY. THE SEM IMAGES INDICATED THE PCM FILLED THE EMPTY SPACES IN THE POROUS SURFACE OF THE RESIDUE FIBERS TO FORM SHAPE-STABILIZED COMPOUNDS. THE FTIR SPECTROMETRY RESULTS INDICATED THE COMPOUNDS STILL EXHIBITED CHARACTERISTIC PEAKS CORRESPONDING TO BOTH THE MDF RESIDUES AND THE PCMS. NO CHEMICAL REACTION WAS OBSERVED BETWEEN THE TWO COMPONENTS. MOREOVER, ACCORDING TO THE TGA RESULTS, THE COMPOUNDS PRODUCED EXHIBIT HIGH THERMAL STABILITY. THE R+PCM1 COMPOUND HAD THE HIGHEST LATENT HEAT CAPACITY OF ALL THE COMPOUNDS DEVELOPED IN THIS STUDY, REACHING A MAXIMUM OF 57.8 J?G?1, AND A PHASE CHANGE TEMPERATURE COMPARABLE TO THAT OF PCM1. THIS BETTER THERMAL PERFORMANCE COULD BE ATTRIBUTED TO THE COMPOUNDS HAVING A HIGHER ENCAPSULATION RATIO (31.4%) THAN THE OTHER COMPOUNDS DEVELOPED. FURTHERMORE, THE R+PCM1 COMPOUND HAD AN ABSORPTI

THIS STUDY FOCUSES ON THE UTILIZATION OF BOLAINA SAWDUST WASTE FROM THE PERUVIAN AMAZON FOR THE PRODUCTION OF CELLULOSE NANOFIBERS (CNFS). BOLAINA IS KNOWN FOR ITS RAPID GROWTH AND EXTENSIVE WOOD USAGE, WHICH GENERATE SIGNIFICANT AMOUNTS OF SAWDUST WASTE. THE OBJECTIVE OF THIS RESEARCH WAS TO PHYSICOCHEMICALLY STUDY THIS BIOMASS SOURCE AND THE CONVERSION OF THIS WASTE INTO VALUABLE NANOCELLULOSIC MATERIALS. THE RESULTS SHOWED THAT CNF YIELDS FROM HOLOCELLULOSE (CNF-BH) AND ALPHA-CELLULOSE (CNF-B?) GAVE HIGH NANOFIBRILLATION YIELDS OF 80.6% AND 74.7%, RESPECTIVELY. ....

SIX EUCALYPTUS NITENS FAMILIES FROM TWO SOILS IN THE 8TH REGION OF CHILE, CLAY AND TRUMAO, WERE STUDIED TO SELECT FAMILIES WITH LOWER DEGREE OF CRACKING. CRACKING PARAMETERS EVALUATED AT MESOSCALE, NEXT TO NANOMECHANICAL PROPERTIES OF THE CELULAR STRUCTURE, WERE RELATED IN A REPRESENTATIVE VOLUMEN ELEMENT OF THESE TREE, SUCH AS PERCENTAGE OF CRACKED AREA OF TREES RELATING THEM TO THE DUCTILITY RATIO (E/H) OBTAINED OF VALUES OF MODULUS OF ELASTICITY (E) AND HARDNESS (H) BY NANOINDENTATION AND THE MODULUS OF RESILIENCE (UR) OF THE MIDDLE LAMELLA AND S2-LAYER OF THE CELL WALL WERE ANALYZED. FURTHERMORE, IT WAS DETERMINED THAT THE DIFFERENCE BETWEEN THE MODULUS OF RESILIENCE (?UR) OF THE MIDDLE LAMELLA WITH THE S2-LAYER IS A GOOD INDICATOR OF THE INTERFACIAL STRESS INDUCING FRACTURES IN THE S1-LAYER. USING NANOCHARACTERIZATION IT WAS ESTABLISHED THAT THE MIDDLE LAMELLA IS MORE BRITTLE AND SUSCEPTIBLE TO GENERATE MICROCRACKS THAT SPREAD TO MESO SCALE. THE ?UR BETWEEN THE MIDDLE LAMELLA AND S2 LAYER SHOWN TO BE LOWER IN FAMILIES 2 AND 5. THESE FAMILIES SHOWED TO HAVE LOWER LEVELS OF SHEAR STRESS AT THE INTERFACE BETWEEN THE MIDDLE LAMELLA AND S2-LAYER, THEREFORE THE AMOUNT OF MICROCRACKS THAT OCCUR IS LOWER, THERE IS A GOOD RELATIONSHIP WITH THE PERCENTAGE OF MEASURED CRACKS IN THESE FAMILIES OF EUCALYPTUS NITENS. ACCORDING THESE FINDINGS, THE FAMILIES THAT SHOW LOW DEGREE OF INTERFACIAL TENSIÓN AT CELULAR LEVEL AND LOW CRACKS INDEX WERE FAMILY 2 AND FAMILY 5.

TIMBER AND WOOD-BASED MATERIALS ARE CONSIDERED SUSTAINABLE BUILDING MATERIALS; HOWEVER, AS THEY ARE PRONE TO DEGRADATION BY BIOTIC AND ABIOTIC FACTORS, THEY OFTEN REQUIRED THE ADDITION OF PROTECTING COATINGS. IN THIS CONTEXT, THE PREFERRED OPTIONS ARE WATERBORNE COATINGS SINCE THEY ARE NON-AGGRESSIVE SOLVENTS (ODOR, TOXICITY, FIRE RISK) AND ULTIMATELY ELIMINATE THE EMISSION OF VOLATILE ORGANIC COMPOUNDS (VOCS). NOTWITHSTANDING, THESE REDUCTIONS IMPLY LOWER DURABILITY AND PROTECTION AS COMPARED TO CONVENTIONAL ORGANIC COATINGS. THIS STUDY DEMONSTRATES THAT INCORPORATING NANOCELLULOSE PRODUCED FROM BLUEBERRY PRUNING RESIDUES AND TITANIUM DIOXIDE AND SILICA DIOXIDE NPS INTO WATERBORNE VARNISHES CAN IMPROVE WOODEN SURFACES MECHANICAL PERFORMANCE AND STABILITY. PARTICULARLY THE ADHESION AND ABRASION PROPERTIES ARE ENHANCED WITHOUT SIGNIFICANT CHANGES IN OTHER PROPERTIES SUCH AS OPTICAL TRANSPARENCY, COLOR, AND COATING GLOSS. THESE RESULTS PRESENT A PROMISING POTENTIAL FOR DIFFERENT APPLICATIONS IN THE CONTEXT OF DEVELOPING PRODUCTS FOR A CIRCULAR ECONOMY IN FURNITURE, FLOORS, AND WOOD PANELING.