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 FIBERS FROM SEVEN EUCALYPTUS SPECIES WERE COLLECTED TO INVESTIGATE THE RELATIONSHIPS AMONG SPECIES, FIBER BIOMETRY, AND NANOMECHANICAL PROPERTIES. THE RESULTS INDICATED SIGNIFICANT DIFFERENCES IN WOOD DENSITY, COARSENESS, FIBER LENGTH, FIBER WIDTH, AND CELL WALL THICKNESS AMONG THE DIFFERENT EUCALYPTUS SPECIES. THE NANOMECHANICAL PROPERTIES OF THE S2 CELL WALL LAYER ALSO SHOWED SIGNIFICANT DIFFERENCES AMONG THE EUCALYPTUS SPECIES. THE ELASTICITY MODULUS RANGED FROM 16 TO 19 GPA, THE HARDNESS SPANNED 0.24 TO 0.31 GPA, AND THE DUCTILITY RATIO WAS BETWEEN 54 AND 68. MOREOVER, SIGNIFICANT CORRELATIONS WERE OBSERVED FOR HARDNESS VERSUS CELL WALL THICKNESS (R = 0.87), AND ELASTICITY MODULUS VERSUS CRYSTALLINITY INDEX (R = 0.80) AND CRYSTALLITE SIZE (R = 0.68). AMONG THE EVALUATED SPECIES, E. DUNNII SHOWED THE HIGHEST ELASTICITY MODULUS, HIGHEST HARDNESS AVERAGE, AND THE HIGHEST CRYSTALLINITY INDEX. THE RANGE OF NANOMECHANICAL VALUES INDICATED THAT EUCALYPTUS WOOD FIBERS ARE SUITABLE FOR THE DEVELOPMENT OF NEW COMPOSITE MATERIALS OR ENGINEERING PRODUCTS BY SELECTING THE MOST ADEQUATE SPECIES FOR EACH USE ACCORDING TO ITS PROPERTIES.

IN THIS WORK, THE IMPREGNATION QUALITY AND MECHANICAL PROPERTIES OF PINUS RADIATA D.DON TREATED WITH DIFFERENT COPPER NANOPARTICLES (CUNP) SOLUTIONS (NAMED K1 AND K2) AND A COMMERCIAL PRESERVATIVE (M) WERE STUDIED. THE IMPREGNATION QUALITY OF RADIATA PINE WOOD WAS ANALYZED BY TWO INDICATORS, PENETRATION AND RETENTION. THE MICRO-DISTRIBUTION OF PRESERVATIVE IN THE TREATED WOOD WAS QUALITATIVELY EVALUATED BY SEM-EDS, BOTH IN THE SAMPLES CONTAINING CUNP AND IN THOSE TREATED WITH THE COMMERCIAL PRESERVATIVE. IN ADDITION, SOME MECHANICAL PROPERTIES WERE STUDIED IN THE PRESERVED WOOD INCLUDING MOE, MOR AND HARDNESS. THE RESULTS INDICATED VALUES BY ED XRF RETENTION OF 0.96 KG/M3 AND 0.86 KG/M3 FOR K1 AND K2, RESPECTIVELY, AND 1.01 KG/M3 FOR M WOOD IMPREGNATED. IN THE PENETRATION DETERMINED BY COLORIMETRIC TEST, THE WOOD SAMPLES IMPREGNATED (WITH K1, K2 AND M) SHOWED 100% PENETRATION. THE DISTRIBUTION OF CUNP AND MICRONIZED COPPER WITHIN THE WOOD NSTRUCTURE WAS CONFIRMED BY SEM EDS MAPPING. IN MECHANICAL PROPERTIES, A REDUCTION IN MOE WAS REFLECTED IN ALL WOOD TREATED. THE CONTROL SAMPLES WERE FAR SUPERIOR TO THE K1 AND M TREATED SAMPLES AND SLIGHTLY SUPERIOR TO THE K2 SAMPLES, WITH NO STATISTICALLY SIGNIFICANT DIFFERENCES. ON THE OTHER HAND, SAMPLES IMPREGNATED WITH K1 AND K2 SHOWED THE HIGHEST VALUES IN HARDNESS PARALLEL AND PERPENDICULAR TO THE GRAIN, REVEALING THAT THESE PRESERVATIVE SOLUTIONS TEND TO INCREASE HARDNESS. OVERALL, WHEN IT COMES TO THE SAMPLES IMPREGNATED WITH MICRONIZED COPPER (M), THE MECHANICAL PROPERTIES WERE CONSIDERABLY LOWER COMPARED TO THE CUNP TREATED AND CONTROL WOOD. THEREFORE, THE CUNP-BASED PRESERVATIVE DID NOT STRONGLY AFFECT THE MECHANICAL PROPERTIES OF THE PRESERVED WOOD.

EUCALYPTUS WOOD FROM ADULT TREES IS USED FOR SEVERAL PURPOSES; HOWEVER, THE WOOD OF YOUNGER TREES HAS LIMITED USE. THIS STUDY AIMS TO CHARACTERIZE AND PROPOSE USES OF TWO-YEAR-OLD EUCALYPTUS WOOD. SIX TWO-YEAR-OLD EUCALYPTUS GRANDIS × EUCALYPTUS UROPHYLLA CLONES HAVE BEEN SELECTED AND THEIR ANATOMICAL, ULTRASTRUCTURAL, PHYSICAL AND MECHANICAL WOOD CHARACTERISTICS EVALUATED. THE WOOD OF CLONE A SHOWS MORE ROBUST FIBERS WITH BETTER MICROFIBRIL ARRANGEMENT, RESULTING IN BETTER MECHANICAL PROPERTIES, AND THEREFORE, A BETTER PERFORMANCE FOR STRUCTURAL USE. CLONE F SHOWED A LOW VARIATION OF WOOD BASIC DENSITY IN THE RADIAL DIRECTION, FACILITATING ITS MACHINABILITY, AND WITH THE CLONE B, SHOWED A LOWER ANISOTROPY, AND THEREFORE, THE WOOD IS RECOMMENDED FOR LOCATIONS WITH HIGH VARIATIONS OF HUMIDITY. THE HETEROGENEITY OF THE WOOD CHARACTERISTICS OF THE EVALUATED CLONES CONFIRMS THE NEED FOR FURTHER STUDIES, TO CHOOSE THOSE MOST ADEQUATE TO EACH USE.

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

ALUMINIUM-DOPED CDS THIN FILMS WERE GROWN, USING CHEMICAL BATH DEPOSITION, ON GLASS SUBSTRATES IN AN AMMONIA-FREE SYSTEM, WITH POST-DEPOSITION THERMAL ANNEALING AT 300 ° C IN AIR ATMOSPHERE. THEIR STRUCTURAL, MORPHOLOGICAL, MECHANICAL, ELECTRICAL AND OPTICAL PROPERTIES WERE STUDIED BY X-RAY DIFFRACTION (XRD), ATOMIC FORCE MICROSCOPE (AFM), NANOINDENTATION, FOUR-POINT PROBES METHOD AND UV-VIS SPECTROPHOTOMETER, RESPECTIVELY. XRD PATTERNS SHOW THAT DOPED CDS FILMS HAVE AN HEXAGONAL STRUCTURE, WITH PREFERRED ORIENTATION ALONG THE (0 0 2) PLANE, AND THEIR AVERAGE CRYSTALLITE SIZE START TO DECREASE WHEN AL CONTENT REACHES A CERTAIN VALUE. THE AFM STUDIES REVEAL THAT SURFACE ROUGHNESS DECREASES WITH THERMAL ANNEALING. ADDITIONALLY, WE FOUND THAT THE YOUNGS MODULUS AND HARDNESS OF THE FILMS DECREASES WITH INCREASING AL DOPING, AND THE ELECTRICAL RESISTIVITY DECREASES WITH THERMAL ANNEALING. THE BAND GAP WAS FOUND TO BE IN THE RANGE OF 2.39?2.49 EV FOR AS-DEPOSITED FILMS AND 2.33?2.39 EV FOR ANNEALED FILMS. CURRENT-VOLTAGE (I-V) MEASUREMENTS WERE ALSO CARRIED OUT TO THE FILMS, WHICH SHOWED RECTIFYING BEHAVIOR WITH AG CONTACTS FOR SOME DOPING LEVELS.

THE OBJECTIVE OF THIS WORK WAS TO TEST A NEW METHODOLOGY TO ASSESS THE RESISTANCE OF TREES TO WIND DAMAGE AND DETERMINE THE CHARACTERISTICS THAT INCREASE CLONE RESISTANCE TO WINDS. TREE RESISTANCE TO BREAKAGE, BASIC DENSITY, ULTRASTRUCTURE, ANATOMY, MECHANICAL PROPERTIES, AND WOOD GROWTH STRESS HAVE BEEN EVALUATED IN SEVEN EUCALYPTUS GRANDIS × EUCALYPTUS UROPHYLLA CLONES, COLLECTED FROM A REGION WITH A HIGH INCIDENCE OF WIND DAMAGE. THE PEARSON CORRELATION COEFFICIENT BETWEEN THE TREE RESISTANCE TO BREAKAGE AND THE RATIO BETWEEN THE AREA DAMAGED BY THE WINDS AND THE TOTAL PLANTED AREA WAS -0.839, SHOWING THE EFFICIENCY OF THE METHODOLOGY ADOPTED AND THAT HIGH BREAKING STRENGTH RESULTS IN A SMALLER AREA AFFECTED BY WIND DAMAGE. TREES WITH A HIGH BASIC DENSITY, CELL WALL FRACTION, MODULUS OF ELASTICITY OF THE MIDDLE LAMELLA AND FIBERS, FIBER HARDNESS, MODULUS OF RUPTURE, GROWTH STRESS AND LOW MICROFIBRIL ANGLE AND HEIGHT AND WIDTH OF THE RAYS SHOWED GREATER RESISTANCE TO WIND DAMAGE. THEREFORE, THE SELECTION OF CLONES WITH THESE FEATURES MAY REDUCE THE INCIDENCE OF DAMAGE BY WINDS IN EUCALYPTUS PLANTATIONS.

INFORMATION ON THE MORPHOLOGICAL AND PHYSICAL PROPERTIES OF BIOFIBERS IS NECESSARY TO SUPPORT THE MECHANICAL UNDERSTANDING OF THE BIOLOGICAL DESIGN OF PLANTS, AS WELL AS FOR THE DEVELOPMENT OF NEW TECHNOLOGY THAT ADDS VALUE TO NON-TRADITIONAL BIORESOURCES, SUCH AS THOSE BASED ON ULEX EUROPAEUS FIBERS. ULEX EUROPAEUS FIBERS WERE EXTRACTED THROUGH A CHEMICAL PULPING PROCESS AT 170 °C AND WITH 40 G/L NAOH. THE DIMENSIONS OF THE FIBERS PRODUCED WERE 0.97 ± 0.1 MM IN LENGTH AND 13 ± 2 ?M IN DIAMETER. PRESSED FIBER PAPER SHEETS WERE MADE TO EVALUATE THEIR MECHANICAL PROPERTIES. BURST AND TEAR INDICES OF 1.2 MN/KG AND 8.6 NM2/KG, RESPECTIVELY, WERE RECORDED. THE VALUES OBTAINED DID NOT COMPARE WELL TO FIBER PAPER SHEETS FROM PINUS RADIATA, PRESUMABLY DUE TO THE SIGNIFICANT AMOUNT OF NON-STRUCTURAL ELEMENTS OF WOOD PRESENT IN THE SAMPLES AND THE LOWER LENGTH OF ULEX EUROPAEUS FIBERS, WHICH RESULTED IN LOWER TENSILE STRENGTH. ADDITIONALLY, NANOINDENTATION TESTS WERE CONDUCTED TO ASSESS THE HARDNESS AND ELASTIC MODULUS OF THE FIBERS, OBTAINING AVERAGE VALUES OF 0.84 GPA AND 9.23 GPA FOR THE STEM, RESPECTIVELY. THESE VALUES WERE SIGNIFICANTLY LOWER THAN THOSE OF INDUSTRIAL BIOFIBER, PERHAPS DUE TO THE LOWER MORPHOGENIC MATURITY OF ULEX EUROPAEUS FIBERS COMPARED TO OTHER TRADITIONAL SOURCES OF FIBER.

INVASIVE TELINE MONSPESSULANA CAN BE AN IMPORTANT SOURCE OF BIOMASS TO SUPPLY FIBERS FOR THE RISING DEMAND OF CELLULOSE BIOPRODUCTS, ESPECIALLY FOR THE DEVELOPMENT OF ADVANCED MATERIALS. ITS FIBERS CAN BE EXTRACTED VIA A THERMO-ALKALINE PROCESS AT 170 °C WITH 40 G/L OF SODIUM HYDROXIDE (NAOH) AND CHARACTERIZED BY CRYSTALLOGRAPHIC, THERMO-ANALYTICAL, AND MECHANICAL TECHNIQUES. THE CELLULOSE PROPORTION IN THE WOOD OF THIS SPECIES IS APPROXIMATELY 47.6 WT.% ± 1.05 WT.%. HOWEVER, ITS FIBERS ARE RELATIVELY SMALL, AND THEY HAVE A WIDE RANGE OF ASPECT RATIOS FROM 25 TO 287, WITH AN AVERAGE DIAMETER OF 9.3 ?M ± 2.5 ?M. THESE CHARACTERISTICS AND MECHANICAL PROPERTIES MAKE THE FIBERS UNATTRACTIVE FOR THE TEXTILE AND PAPER INDUSTRIES. MEANWHILE, CRYSTALLINE CELLULOSE WAS PREVALENT IN THE MONOCLINIC PHASE, WITH A CRYSTALLINE INDEX AND CRYSTALLINE PORTION OF 78 AND 41%, RESPECTIVELY, OBSERVING CRYSTAL DOMAINS OF C.A. 3.2 NM. NANOINDENTATION TESTS REVEALED FAVORABLE VALUES OF ELASTIC MODULUS AND HARDNESS OF C.A. 16 GPA AND 0.28 GPA, RESPECTIVELY. THUS, THIS BIORESOURCE IS EXPECTED TO SEE PROMISING APPLICATIONS IN MATERIALS ENGINEERING, SUCH AS REINFORCEMENT IN MATERIAL COMPOSITES, IN DRUG DELIVERY CARRIER, AND ELECTRONIC DEVICES, AMONG OTHER BIOMULTIFUNCTIONAL COMPONENTS.

THE OBJECTIVE OF THIS RESEARCH WAS TO STUDY THE CHEMICAL AND NANOMECHANICAL CHARACTERISTICS OF NATIVE WOODS GROWN IN SOUTHERN CHILE REGION. THE SPECIES ANALYSED WERE DRIMYS WINTERI, LAURELIOPSIS PHILIPPIANA, AEXTOXICON PUCTATUM, NOTHOFAGUS ALPINA, NOTHOFAGUS DOMBEYI, LAURELIA SEMPERVIRENS, AUSTROCEDRUS CHILENSIS AND FITZROYA CUPRESSOIDES. THE SAMPLES WERE COLLECTED FROM THE REGIONS OF BIOBÍO (37° S, 73° W), ARAUCANÍA (37° S, 71° W) AND LOS LAGOS (40° S, 73° W). CHEMICAL ANALYSIS REPORTED THAT GLUCAN CONTENT OF NATIVE WOODS WAS BETWEEN 39% AND 44% AND LIGNIN CONTENT BETWEEN 28% AND 35%. THE NANOMECHANICAL PROPERTIES ANALYSED IN THE SECONDARY CELL WALL (S2 LAYER) AND MIDDLE LAMELLA (ML) WERE ELASTIC MODULUS (E), HARDNESS (H) AND DUCTILITY RATIO (E/H). VALUES FOR ES2 WERE BETWEEN 12.0 AND 15.4 GPA AND FOR EML BETWEEN 4.3 AND 6.6 GPA. HARDNESS VALUES WERE SIMILAR IN ML AND S2 (?0.3 GPA). THE COMPILATION OF RESULTS SHOWED HIGH CORRELATIONS BETWEEN ES2 AND CARBOHYDRATE CONTENT (R = 0.80), BETWEEN ES2 AND HEMICELLULOSE CONTENT (R = 0.89), AND BETWEEN HS2 AND LIGNIN CONTENT (R = 0.88).

CHUSQUEA QUILA OR ?QUILA?, IS ONE OF THE MOST ABUNDANT LESSER-KNOWN SPECIES FROM CHILE, AND FOR MANY YEARS IT HAS CREATED PROBLEMS FOR FARMERS IN THE SOUTHERN PART OF THIS COUNTRY. IN THIS STUDY, IT WAS EXAMINED AS A PROMISING RESOURCE FOR HIGH-TECH MATERIALS. THE CHEMICAL AND PHYSICAL PROPERTIES WERE DETERMINED BY ASTM STANDARDS. THE EXTRACTIVES, ASH CONTENT, LIGNIN, AND ALPHA-CELLULOSE WERE 4.55%, 2.17%, 13.78%, AND 54.65%, RESPECTIVELY. THE HIGHER HEATING VALUE AND BASIC DENSITY OBTAINED WERE 5,106 KCAL/KG AND 290 KG/M3, RESPECTIVELY. THE MOISTURE CONTENT WAS STUDIED DURING FOUR SEASONS AND FOUND TO BE THE HIGHEST IN WINTER (73%). REGARDING THE NANOMECHANICAL PROFILES, HARDNESS VARIED FROM 0.16 GPA IN THE CORTEX TO 0.21 GPA IN THE NODULE. THE AVERAGE ELASTIC MODULUS IN THE NODULE AND INTERNODE WAS 12.5 GPA, WHILE IN THE CORTEX IT WAS 7.45 GPA. CONSIDERING THE HIGH CELLULOSE CONTENT AND STRUCTURAL FEATURES OF THE LIGNOCELLULOSIC MATRIX, IT COULD BE POSSIBLE TO EXTRACT CELLULOSE FIBERS FOR COMMERCIAL USE AND CRUDE LIGNIN FOR TESTING NEW APPLICATIONS. THUS, THE ENTIRE QUILA STRUCTURE IS A POTENTIAL BIOMASS RESOURCE.

TO STUDY MATERIAL DAMAGE IN WOOD CELLS DURING ANY TRANSFORMATION PROCESS, ONE MUST CONSIDER THE MOLECULAR ARCHITECTURE OF NATURAL CELLULOSIC FIBERS, WHICH MAY EVENTUALLY IMPACT THE OVERALL MECHANICAL BEHAVIOR OF WOOD FIBERS. IN PARTICULAR WOOD SPECIES, ANATOMICAL FEATURES AND MECHANICAL PROPERTIES OF THE CELL WALL MAY DETERMINE THE POTENTIAL FOR STRESS TRANSFER IN HYBRID MATERIALS. IN THIS STUDY, WE QUANTIFIED WOOD CELL DAMAGE IN TERMS OF THE STIFFNESS REDUCTION OF THE S2 LAYER FOR THE CELL WALL BY MEASURING YOUNG?S MODULUS WITH NANOINDENTATIONS OF THE CELL WALL BEFORE AND AFTER PROCESSING. WE THEN PROPOSE AND VALIDATE A MODIFIED RULE OF MIXTURES BASED ON A DAMAGE PARAMETER AFFECTED BY THE LATEWOOD PROPORTION AND CELL WALL PROPERTIES.

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 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 MAIN OBJECTIVE OF THIS STUDY WAS TO DEVELOP CELLULOSE NANOFIBERS FROM THE THERMOME- CHANICAL PULP (TMP) OF RADIATA PINE (PINUS RADIATA D. DON), AND FOR THIS, A ONE-STEP MICRO-GRINDING PROCESS WAS USED. THE NEWLY DEVELOPED MATERIAL WAS CALLED THERMOMECHANICAL PULP NANOFIBERS (TMP-NF). IN THE FIRST INSTANCE, A DETERMINATION OF THE CONSTITUENTS OF THE TMP WAS CARRIED OUT THROUGH A CHEMICAL CHARACTERIZATION. THEN, TMP-NFS WERE COMPARED WITH CELLULOSE NANOFIBERS (CNF) BY MORPHOLOGICAL ANALYSIS (SCANNING ELECTRON MICROSCOPY, SEM, AND ATOMIC FORCE MICROSCOPY, AFM), X-RAY DIFFRACTION (XRD) AND FOURIER-TRANSFORM INFRARED SPECTROSCOPY WITH ATTENUATED TOTAL REFLECTION (FTIR-ATR). IN ADDITION, FILMS WERE DEVELOPED FROM TMP-NF AND CNF USING A VACUUM FILTRATION MANUFACTURING METHOD. FOR THIS STUDY, 0.10, 0.25, 0.50, AND 1.00% DRY WEIGHT OF CNF AND TMP- NF WERE USED AS CONTINUOUS MATRICES WITHOUT ORGANIC SOLVENTS........

FORESTRY INDUSTRIES IN CHILE ARE FACING AN IMPORTANT CHALLENGE-DIVERSIFYING THEIR PRODUCTS USING GREEN TECHNOLOGIES. IN THIS STUDY, THE POTENTIAL USE OF IONIC LIQUIDS (ILS) TO DISSOLVE AND HYDROLYZE EUCALYPTUS WOOD (MIX OF EUCALYPTUS NITENS AND EUCALYPTUS GLOBULUS) KRAFT PULP WAS STUDIED. THE BLEACHED HARDWOOD KRAFT PULP (BHKP) FROM A CHILEAN PULP MILL WAS USED TOGETHER WITH FIVE DIFFERENT ILS: 1-BUTYL-3-METHYLIMIDAZOLIUM CHLORIDE [BMIM][CL], 1-BUTYL-3-METHYLIMIDAZOLIUM ACETATE [BMIM][AC], 1-BUTYL-3-METHYLIMIDAZOLIUM HYDROGEN SULFATE [BMIM][HSO4], 1-ETHYL-3-METHYLIMIDAZOLIUM CHLORIDE [EMIM][CL], 1-ETHYL-3-METHYLIMIDAZOLIUM ACETATE [EMIM][AC]. EXPERIMENTALLY, ONE VACUUM REACTOR WAS DESIGNED TO STUDY THE DISSOLUTION/HYDROLYSIS PROCESS FOR EACH ILS; PARTICULARLY, THE CELLULOSE DISSOLUTION PROCESS USING [BMIM][CL] WAS STUDIED PROPOSING ONE MOLECULAR DYNAMIC MODEL. EXPERIMENTAL CHARACTERIZATION USING ATOMIC FORCE MICROSCOPY, CONDUCTOMETRIC TITRATION, AMONG OTHER TECHNIQUES SUGGEST THAT ALL ILS ARE CAPABLE OF CELLULOSE DISSOLUTION AT DIFFERENT LEVELS; IN SOME CASES, THE DISSOLUTION EVOLVED TO PARTIAL HYDROLYSIS APPEARING CELLULOSE NANOCRYSTALS (CNC) IN THE FORM OF SPHERICAL AGGREGATES WITH A DIAMETER OF 40-120 NM. MOLECULAR DYNAMICS SIMULATIONS SHOWED THAT THE [BMIM][CL] ANIONS TEND TO INTERACT ACTIVELY WITH CELLULOSE SITES AND WATER MOLECULES IN THE DISSOLUTION PROCESS. THE RESULTS SHOWED THE POTENTIAL OF SOME ILS TO DISSOLVE/HYDROLYZE THE CELLULOSE FROM CHILEAN EUCALYPTUS, MAINTAINING REACTIVE FORMS.

THE ACCUMULATION OF PLASTIC WASTE AND INFECTIOUS DISEASES HAS LED THE SCIENTIFIC COMMUNITY TO SEARCH FOR NEW MATERIALS TO MAKE NANOCOMPOSITES BIOFILMS. WITH THE HELP OF NANOTECHNOLOGY, THE MATERIALS THAT MAKE UP THE NEW NANOCOMPOSITES BIOFILM CAN BE MANIPULATED, ACHIEVING AN IMPROVEMENT IN ITS MECHANICAL PROPERTIES AND GRANTING ANTIMICROBIAL POWERS. BIOFILMS BASED ON ELECTROSPUN FIBERS AS A BARRIER MATERIAL CAN PROTECT AGAINST INFECTIOUS MICROORGANISMS. FOR THESE APPLICATIONS, THE ELECTROSPINNING METHOD ALLOWS THE ENCAPSULATION OF ACTIVE AGENTS IN THE POLYMERIC FIBERS. THIS ARTICLE PRESENTS THE DEVELOPMENT OF A NANOCOMPOSITES BIOFILM WITH POTENTIAL USE AS AN ANTIMICROBIAL BARRIER, WHICH INCORPORATES POLYLACTIC ACID MICROFIBERS WITH ACTIVE AGENTS. AMONG THEM, COPPER IONS SUPPORTED ON CHILEAN NATURAL ZEOLITE NANOPARTICLES AND REINFORCED WITH ACETYLATED CELLULOSE NANOFIBERS. THE STUDY BEGINS WITH OBTAINING CELLULOSE NANOFIBERS THROUGH MECHANICAL METHODS. NANOFIBERS WERE ACETYLATED TO ENSURE ADEQUATE DISPERSION IN THE POLYMER MATRIX AND TO IMPROVE THE MECHANICAL PROPERTIES OF BIOFILMS. POLYMERS AND NANOPARTICLES WERE INCORPORATED INTO BIOFILMS THROUGH A DUAL CONFIGURATION (SIMULTANEOUS INJECTION) ELECTROSPINNING STAGE.

EFFECT OF LA- AND/OR NB-DOPING ON STRUCTURE AND ELASTIC BEHAVIOR OF BAFEO3?? AT ROOM TEMPERATURE AND 850 ?C WERE STUDIED AND COMPARED. THE COMPARISON OF THE MICROSTRUCTURES AND GRAIN SIZE DISTRIBUTIONS OF DENSIFIED BA0.95LA0.05FEO3?? (BLFO), BAFE0.9NB0.1O3?? (BFNO) AND B0.95LA0.05AFE0.9NB0.1O3?? (BLFNO) SHOWED THAT NB-DOPING HINDERED GRAIN GROWTH DURING SINTERING. THE XRD ANALYSES OF SINTERED SAMPLES DEMONSTRATES THAT LA-DOPING IS MORE EFFECTIVE THAN NB-DOPING FOR STABILIZATION OF HIGH TEMPERATURE SYMMETRIC CUBIC STRUCTURE AS IT PROVED BY BLFO?S LINEAR ELASTIC BEHAVIOR IN CYCLIC COMPRESSION STRESS?STRAIN CURVES. BFNO AND BLFNO EXHIBITED FERROELASTIC BEHAVIOR AT ROOM TEMPERATURE DUE TO PRESENCE OF NON-SYMMETRIC PHASES IN THEIR STRUCTURES. ALL SAMPLES SHOWED LINEAR ELASTIC BEHAVIOR AT 850 ?C WITH REMNANT STRAIN DUE TO HIGH TEMPERATURE CREEP DEFORMATIONS. BOTH LA- AND NB-DOPING CAN IMPROVE CREEP RESISTANCE OF BAFEO3??

THE INFLUENCE OF LOAD ON THE CELLULOSE MICROFIBRILS OF SINGLE CELLS OR THIN WOOD FOILS IS KNOWN. IT CAN DECREASE THE CELLULOSE MICROFIBRIL ANGLES AND, IN TURN, INCREASE THE STIFFNESS. HOWEVER, THIS MODIFICATION OF A PIECE OF WOOD, WHICH IS MADE UP OF MULTIPLE CELLS, IS UNKNOWN. THE AIM OF THIS RESEARCH WAS TO STUDY THE EFFECT OF TENSILE CREEP ON THE LONGITUDINAL STIFFNESS OF RADIATA PINE WOOD. THE MODULUS OF ELASTICITY OF EACH SPECIMEN WAS DETERMINED BEFORE AND AFTER BEING SUBJECTED TO TENSILE CREEP. THE SAMPLES WERE LOADED AT 1170 N AND 1530 N FOR 20 MIN AT 70 °C. THE LOAD WAS DETERMINED AS A FUNCTION OF A PERCENTAGE OF THE FORCE AT THE PROPORTIONAL LIMIT. THE MODULI OF ELASTICITY BEFORE AND POST-TENSILE CREEP SHOWED NO EFFECT ON THE STIFFNESS OF WOOD AT THE MACROSCOPIC LEVEL, BUT NEITHER WERE THERE DAMAGE TO THE CELL STRUCTURE. IT CAN BE ASSUMED THAT THERE ARE CHANGES AT THE MICROSCOPIC LEVEL, BUT THEY ARE NOT ENOUGH TO BE REFLECTED AT THE MACRO SCALE. IT IS ALSO CHALLENGING TO ACHIEVE THE MODIFICATIONS THAT OCCUR AT THE LEVEL OF A SINGLE CELL OR IN THIN WOOD FOILS; HOWEVER, THE IMPLICATIONS OF THIS WOULD BE FAVORABLE FOR THE DEVELOPMENT OF STRONGER WOOD-BASED PRODUCTS.