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.

THIS ARTICLE PRESENT THE DATA OF THE STUDY OF THE STRUCTURAL, OPTICAL AND VIBRATIONAL PROPERTIES OF CDS:AL THIN FILMS SYNTHESIZED BY CHEMICAL BATH DEPOSITION (CBD) METHOD AFTER AGING. THE SAMPLES WERE CHARACTERIZED BY X-RAY DIFFRACTION, UV-VIS AND PHOTOLUMINESCENCE SPECTROSCOPY, AND RAMAN SPECTROSCOPY. X-RAY DIFFRACTION PATTERN OF THE SAMPLES DISCLOSED HEXAGONAL CRYSTALLINE STRUCTURE OF CDS. THE CRYSTALLITE SIZE WAS ESTIMATED FOR EACH THIN FILM. THE ENERGY BAND GAP WAS CALCULATE USING THE TAU PLOT METHOD. THE SAMPLES PRESENT DEFECTS IN THEIR STRUCTURE. A DETAILED STUDY ON THE STRUCTURE WAS CARRY OUT IN THE REGION OF 200 TO 800 CM-1, WHERE THE 1LO AND 2LO PHONON MODES ARE PRESENTS. THE DATA HAVE NOT BEEN REPORTED NOR DISCUSSED FOR NOW.

REVISTA INGENIERÍA Y COMPETITIVIDAD ISSN 0123-3033

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 USE OF SOLAR RADIATION TO GENERATE ELECTRICITY IS A PROMISING SOLUTION TO THE GLOBAL ENERGY CRISIS, DUE TO ITS LOW CARBON FOOTPRINT AND GLOBAL AVAILABILITY. IN THIS SENSE, THIN FILM SOLAR CELLS ARE AN INTERESTING ALTERNATIVE BECAUSE OF ITS GOOD CONVERSION EFFICIENCIES AND THE SMALL AMOUNT OF MATERIAL NEEDED FOR THEIR MANUFACTURE [1]. ON THE OTHER HAND, NANOSTRUCTURED METAL SULFIDES HAVE BEEN EXTENSIVELY STUDIED DUE TO THEIR EXCELLENT PROPERTIES AND PROMISING APPLICATIONS IN ELECTRONIC AND OPTOELECTRONIC DEVICES, SUCH AS SOLAR CELLS, LIGHT-EMITTING DIODES, AND NON-VOLATILE MEMORIES [2]. IN THIS SENSE, CDS IS A COMMONLY USED OPTICAL WINDOW MATERIAL IN THIN FILM SOLAR CELLS, DUE TO ITS HIGH OPTICAL TRANSPARENCY, WIDE BANDGAP ENERGY (2.42 EV) AND N-TYPE CONDUCTIVITY. TO USE AS AN ABSORBER LAYER, PBS HAS INTERESTING FEATURES LIKE DIRECT BANDGAP ENERGY (0.41 EV AT 300 K) P TYPE CONDUCTIVITY, AND LARGE EXCITON RADIUS (18 NM) WHICH PROVIDES STRONG QUANTUM CONFINEMENT OF ELECTRONS AND HOLES, THUS INCREASING THE ABSORPTION FOR SOLAR RADIATION IN THE NEAR INFRARED REGION [3]. IN THIS WAY, CDS/PBS THIN FILM SOLAR CELLS WITH LAYERS DEPOSITED BY MEANS OF CHEMICAL BATH DEPOSITION HAVE BEEN INVESTIGATED BY SEVERAL AUTHORS, WHERE THEY HAVE OBTAINED GOOD EFFICIENCIES BETWEEN 0.44 % AND 4.85 % [3-6]. CURRENTLY, CHEMICAL BATH DEPOSITION (CBD) IS A LOW-COST, SCALABLE AND EASY TECHNIQUE TO SYNTHESIZE SEMICONDUCTOR THIN-FILMS [3-7]. NOW, IN BOTH SEMICONDUCTORS IT IS POSSIBLE TO MODIFY THEIR PROPERTIES BY INTRODUCING METALLIC DOPANTS INTO THEIR STRUCTURE, LIKE ITS BANDGAP VALUE AND ELECTRICAL CONDUCTIVITY. IN THIS SENSE, DOPING WITH AL HAS BEEN REPORTED FOR CHEMICALLY-DEPOSITED CDS AND PBS FILMS SHOWING IN BOTH CASES AN IMPROVEMENT IN THEIR ELECTRICAL CONDUCTIVITY AND A MODIFICATION OF ITS BANDGAP ENERGY AND CRYSTALLITE SIZE [6-9]. MOREOVER, DIFFERENT OPTOELECTRONIC DEVICES HAVE BEEN REPORTED RECENTLY USING CBD AL-DOPED CDS THIN FILMS [10-13].

OLIGOMERIC ?-AMYLOID PEPTIDE (A?) IS ONE OF THE MAIN NEUROTOXIC AGENTS OF ALZHEIMERS DISEASE (AD). OLIGOMERS ASSOCIATE TO NEURONAL MEMBRANES, FORMING """"PORE-LIKE"""" STRUCTURES THAT CAUSE INTRACELLULAR CALCIUM AND NEUROTRANSMITTER DYSHOMEOSTASIS, LEADING TO SYNAPTIC FAILURE AND DEATH. THROUGH MOLECULAR SCREENING TARGETING THE C TERMINAL REGION OF A?, A REGION INVOLVED IN THE TOXIC PROPERTIES OF THE PEPTIDE, WE DETECTED AN FDA APPROVED COMPOUND, GABAPENTIN (GBP), WITH NEUROPROTECTIVE EFFECTS AGAINST A? TOXICITY. AT MICROMOLAR CONCENTRATIONS, GBP ANTAGONIZED PEPTIDE AGGREGATION OVER TIME AND REDUCED THE A? ABSORBANCE PLATEAU TO 28% OF CONTROL. IN ADDITION, GBP DECREASED A? ASSOCIATION TO MEMBRANES BY ALMOST HALF, AND THE EFFECTS OF A? ON INTRACELLULAR CALCIUM IN HIPPOCAMPAL NEURONS WERE ANTAGONIZED WITHOUT CAUSING EFFECTS ON ITS OWN. FINALLY, WE FOUND THAT GBP WAS ABLE TO BLOCK THE SYNAPTOTOXICITY INDUCED BY A? IN HIPPOCAMPAL NEURONS, INCREASING POST-SYNAPTIC CURRENTS FROM 1.7 ± 0.9 TO 4.2 ± 0.7 FC AND MEAN RELATIVE FLUORESCENCE INTENSITY VALUES OF SV2, A SYNAPTIC PROTEIN, FROM 0.7 ± 0.09 TO 1.00 ± 0.08. THE RESULTS SHOW THAT GBP CAN INTERFERE WITH A?-INDUCED TOXICITY BY BLOCKING MULTIPLE STEPS, RESULTING IN NEUROPROTECTION, WHICH JUSTIFIES ADVANCING TOWARD ADDITIONAL ANIMAL AND HUMAN STUDIES.

THIN FILMS OF CDS AND AL-DOPED CDS HAVE BEEN SUCCESSFULLY DEPOSITED ON GLASS SUBSTRATES BY USING A CBD TECHNIQUE AND THEIR PROPERTIES WERE INVESTIGATED. THE STRUCTURAL ANALYSIS CONFIRMED THE HEXAGONAL STRUCTURE OF CDS WITH PREFERENTIAL ORIENTATION ALONG (0 0 2) PLANES. CRYSTALLITE SIZES DECREASES WITH AL CONTENT. THE AFM IMAGES OF THE FILMS SHOW CHANGES IN MORPHOLOGY WITH INCREASE THE DOPANT CONCENTRATION. RAMAN SCATTERING WERE COMPOSED OF FUNDAMENTAL LONGITUDINAL OPTICAL (LO) MODES AND THEIR MULTI-PHONON PROCESS. TRANSMITTANCE, REFLECTANCE, REFRACTION INDEX AND EXTINCTION COEFFICIENT WERE STUDIED TO EXTRACT THE OPTICAL PROPERTIES VARIATION UPON AL DOPING. THE INCREASE OF THE LATTICE STRAIN DUE TO AL DOPING MODIFIES THE OPTICAL PROPERTIES OF THE FILMS. THE ENERGY BAND GAP WAS FOUND TO INCREASE FROM 2.3 TO 2.6 EV WITH INCREASE IN AL CONTENT. THE DOPING ALSO AFFECTS THE PHOTOLUMINESCENCE PROPERTIES OF CDS CRYSTAL STRUCTURE, CAUSING A SHIFT TOWARDS SHORTER WAVELENGTHS OF THE PEAKS OF AL-DOPED FILMS.

IN THE FINAL PROCESS OF THE BLEACHED KRAFT PULP THERE ARE SOME CELLULOSE FIBERS THAT ARE SEPARATED FROM THE MAIN FIBERS STREAM; THESE FIBERS ARE REJECTED AND CONSIDERED AS A LOW QUALITY FIBERS, THESE FIBERS ARE KNOWN AS REJECTED FIBER (RF). IN THE PRESENT WORK THE POTENTIAL USE OF THESE FIBERS FOR CELLULOSE NANOCRYSTALS (CNCS) SYNTHESIS WAS STUDIED. THE PHYSICAL AND CHEMICAL PROPERTIES OF SYNTHESIZED CNCS WERE CHARACTERIZED THROUGH DIFFERENT TECHNIQUES SUCH AS ATOMIC FORCE MICROSCOPY (AFM), SCANNING ELECTRON MICROSCOPY (SEM), X-RAY DIFFRACTION (XRD), FOURIER-TRANSFORM INFRARED SPECTROSCOPY (FTIR), AND THERMOGRAVIMETRIC ANALYSIS (TGA). RESULTS DEMONSTRATE THE FEASIBILITY OF CNCS SYNTHESIS WITH A YIELD OF 28.1% AND 36.9%, AND CRYSTALLINITY OF 73.5% AND 82.7%. FINALLY, THE MORPHOLOGY AND SYNTHESIS CONDITIONS SUGGEST THAT THIS INDUSTRIAL REJECT FIBER (RF) COULD BE USED AS A SOURCE FOR THE CNCS PRODUCTION, THUS ADDING VALUE TO THE KRAFT PROCESS AND OPENING NEW POSSIBILITIES FOR INNOVATION IN THE PULP INDUSTRY.

IN THIS ARTICLE, IT IS INVESTIGATED THE EFFECT OF AL DOPING IN THE JUNCTION PARAMETERS OF AG/CDS:AL THIN-FILM SCHOTTKY DIODES AND THEIR ELECTRICAL RESPONSE TO MICROWAVE IRRADIATION. NANOCRYSTALLINE CDS:AL THIN-FILMS WITH THICKNESSES BETWEEN 109 AND 173 NM WERE PREPARED BY CHEMICAL BATH DEPOSITION AND, SUBSEQUENTLY, AG THIN-FILMS WITH AN AVERAGE THICKNESS OF 102 NM WERE GROWN ON THE CDS:AL USING DC SPUTTERING. THE STRUCTURAL, CHEMICAL, MORPHOLOGICAL AND OPTICAL PROPERTIES OF CDS:AL AND AG FILMS WERE CHARACTERIZED BY X-RAY DIFFRACTION (XRD), SCANNING ELECTRON MICROSCOPE, ATOMIC FORCE MICROSCOPE, ENERGY-DISPERSIVE X-RAY SPECTROSCOPY AND UV-VIS SPECTROPHOTOMETER, RESPECTIVELY. CURRENT-VOLTAGE (I - V) CHARACTERISTICS OF AG/CDS:AL DIODES, WITH DIFFERENT AL CONTENT, WERE OBTAINED AT ROOM TEMPERATURE IN DARK CONDITIONS. XRD STUDIES SHOWS THAT CDS:AL AND AG THIN-FILMS HAVE AN HEXAGONAL AND CUBIC STRUCTURE, RESPECTIVELY. CRYSTALLITE SIZES DECREASES WITH AL CONTENT FOR CDS:AL FILMS AND WERE FOUND TO BE IN THE 15-40 NM RANGE. A DECREASE IN THE INTENSITY OF THE XRD MAIN PEAK OF CDS:AL FILMS IS OBSERVED, CAUSED BY THE INCLUSION OF AMORPHOUS AL2O3 ON THE CDS FILM. IT WAS FOUND THAT BAND GAP OF CDS:AL FILMS INCREASES WITH INCREASING AL CONTENT, FROM 2.28 EV TO 2.40 EV. BASED ON THE I - V CHARACTERISTICS OF THE DIODES, THEIR BARRIER HEIGHT (0), IDEALITY FACTOR N, AND SERIES RESISTANCE R-S WERE CALCULATED, AND IT WAS FOUND THAT THESE VALUES ARE MODIFIED BY INCREASING AL CONTENT IN CDS FILMS, IN THE RANGES: (0): 0.7037-0.8426 EV; N: 3.485-4.213; R-S: 0.54-9.86 M OMEGA. BESIDES, IT WAS STATED THAT AL DOPING CHANGES THE AVERAGE SURFACE ROUGHNESS AND THE ENERGIES OF THE CHARGE NEUTRALITY LEVELS OF CDS:AL FILMS. THE EFFECTS OF PHYSICAL PROPERTIES OF THE FILMS ON THE JUNCTION PARAMETERS OF THE DIODES WERE ALSO DISCUSSED. FINALLY, I - V CHARACTERISTICS OF THE AG/CDS:AL DIODES WERE STUDIED UNDER X-BAND MICROWAVE IRRADIATION AT ROOM TEMPERATURE IN DARK CONDITIONS. FOR A SPECIFIC AL DOPING VA

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.

THIS ARTICLE DESCRIBES THE PRODUCTION OF NANOPARTICLES OF CHILEAN NATURAL ZEOLITE, USING THREE SIZE REDUCTION METHODS: BALL MILL, MICROGRINDING, AND MICROFLUIDIZATION. MORPHOLOGICAL CHARACTERIZATION OF SAMPLES INDICATED AN AVERAGE DIAMETER OF 37.2 ± 15.8 NM OF THE ZEOLITE PARTICLES. THE SIZE REDUCTION AND CHEMICAL TREATMENTS DID NOT AFFECT THE MORPHOLOGY OR INTEGRITY OF THE ZEOLITE. AN INCREASE OF THE ZEOLITE SAMPLES SI/AL RATIO WAS OBSERVED AFTER THE ACID TREATMENT AND WAS CONFIRMED BY SEM-EDX ANALYSIS. MOREOVER, THE EFFECTIVENESS OF THE COPPER SALT ION EXCHANGE (CU2+) TO THE ZEOLITE NANOPARTICLES WAS ANALYZED BY SEM-EDX. XRD ANALYSIS INDICATED THAT CLINOPTILOLITE AND MORDENITE ARE THE MAIN PHASES OF CHILEAN NATURAL ZEOLITE, AND THE CRYSTALLINE STRUCTURE WAS NOT AFFECTED BY THE MODIFICATION PROCESSES. THE FTIR CHARACTERIZATION SHOWED THE PRESENCE OF CHEMICAL BONDS OF COPPER WITH THE ZEOLITE NANOPARTICLE FRAMEWORK. THE ION-EXCHANGED ZEOLITE NANOPARTICLES WERE EVALUATED FOR ANTIBACTERIAL BEHAVIOR BY THE DISC DIFFUSION METHOD. ADDITIONALLY, THE MINIMUM INHIBITORY CONCENTRATION AND MINIMUM BACTERICIDAL CONCENTRATION WERE OBTAINED. MICROBIOLOGICAL ASSAYS WITH COPPER-EXCHANGED NANOZEOLITES SHOWED AN ANTIMICROBIAL ACTIVITY WITH A BACTERICIDAL EFFECT AGAINST ESCHERICHIA COLI AND STAPHYLOCOCCUS AUREUS, WHICH ARE THE PRIMARY PATHOGENS OF FOOD AND ARE ALSO RESISTANT TO MULTIPLE DRUGS. IN THIS STUDY, A NEW APPLICATION FOR NATURAL NANOZEOLITES IS DEMONSTRATED, AS THE INCORPORATED COPPER IONS (CU2+) IN NANOZEOLITES REGISTERED A PRODUCTIVE ANTIBACTERIAL ACTIVITY.

THE NON-DESTRUCTIVE TECHNIQUES ARE A VERY IMPORTANT TOOL IN THE PROCESS OF WOOD CHARACTERIZATION AND EVALUATION. IN THIS WORK, THE OBJECTIVE IS THE EVALUATION OF PHYSICAL AND MECHANICAL PROPERTIES OF SOME NATIVE CHILEAN WOOD SPECIES BY USING THE ULTRASOUND TECHNIQUES AND THEIR COMPARISION WITH THE RESULTS OF TYPICAL MECHANICAL TESTS. THE SELECTED WOODS WERE FOUR HARDWOODS: TEPA (LAURELIOPSIS PHILIPIANA), OLIVILLO (AEXTOXICON PUNCTATUM), LAUREL (LAURELIA SEMPERVIRENS) AND LENGA (NOTHOFAGUS PUMILIO) AND TWO SOFTWOODS: ALERCE (FITZROYA CUPRESSOIDES) AND MAÑÍO (PODOCARPUS NUBIGENA). THE EQUIPMENT USED WERE TWO TYPES OF ULTRASOUND GENERATORS: STEINKAMP BP5 AND PANAMETRIC EPOCH XT. THE RESULTS SHOWN A HIGHER ANISOTROPY FOR HARDWOODS THAN FOR SOFTWOODS, AND A RELATIVELY SYMMETRY FOR TRANSVERSAL WAVE PROPAGATION VELOCITIES AND FOR SHEAR MODULUS OF ELASTICITY, ALONG THE PRINCIPAL DIRECTIONS OF THE TREE. AT THE SAME TIME THE MEAN VALUES OF YOUNG MODULUS OF ELASTICITY (MOE) OBTAINED BY USING THE ULTRASOUND EQUIPMENTS WERE A 25-47 % HIGHER THAN THE SAME MODULUS MEASURED BY MECHANICAL TESTS.

HERE, WE PROPOSE AN ORIGINAL METHOD OF PHOTOCHEMICAL DEPOSITION FOR THE SYNTHESIS OF METAL OXIDES FROM COORDINATION COMPLEXES SENSITIVE TO UV LIGHT. THE METHOD CONSISTS OF THE SYNTHESIS OF ZINC OXIDE AMORPHOUS FILMS DOPED WITH DIFFERENT CONCENTRATIONS OF COPPER OXIDE FOLLOWED BY ANNEALING AT 600 °C. THE PHOTO-REACTIVITY OF THE SAMPLES WAS EVALUATED BY THE DECREASE OF THE FT-IR SPECTROSCOPY BANDS. THE FILMS WERE ANALYZED BY SCANNING ELECTRON MICROSCOPY (SEM-EDX) AND X-RAY DIFFRACTION (XRD) TO STUDY THEIR MORPHOLOGY AND STRUCTURES, RESPECTIVELY. THE RESULTS SHOW AN AMORPHOUS CHARACTERISTIC IN THE PHOTO-DEPOSITS. THE OPTICAL PROPERTIES SHOW A GRADUAL DECREASE OF BOTH THE OPTICAL BAND GAP AND THE LUMINESCENT EMISSIONS OF THE ZNO PHOTO-DEPOSITS WHEN CUO DOPING INCREASES. BOTH PROPERTIES ALLOW A SHIFT IN ABSORPTION TOWARDS THE VISIBLE AND A DECREASE IN THE RATE OF RECOMBINATION OF CHARGE CARRIERS. THE PHOTOCATALYTIC ACTIVITY WAS ANALYZED USING METHYL ORANGE AND METHYLENE BLUE AS POLLUTANTS UNDER A LAMP THAT EMULATES SOLAR ENERGY. THE RESULTS SHOW THAT THE PHOTOCATALYTIC ACTIVITY IS FAVORED BY THE INSERTION OF CUO; 46.6 AND 93.0% EFFICIENCY IN THE PHOTODEGRADATION OF METHYL ORANGE AND METHYLENE BLUE, RESPECTIVELY, WERE REACHED AT 1.0 MOL % OF CUO WITH RESPECT TO PURE ZNO. THESE DIFFERENCES IN DEGRADATION EFFICIENCY RESPOND TO THE CHEMICAL STABILITY OF THE DYES. FINALLY, THE USE OF APPROPRIATE SCAVENGERS SUGGESTS AN OXIDATIVE ROUTE IN THE DYE DEGRADATION MECHANISM.

KRAFT PULP CELLULOSE WAS HYDROLYZED USING SULFURIC ACID, UNDER DIFFERENT THERMOPHYSICAL CONDITIONS OF TEMPERATURE, TIME, PULP CONCENTRATION, AND SONICATION TIME. THE EXPERIMENTAL DESIGN REVEALED THE EFFECT OF THESE CONDITIONS AND THEIR INTERACTION ON THE HYDROLYSIS YIELD OBTAINED. IN ADDITION, THE TOP FIVE CELLULOSE NANOCRYSTALS (CNCS) YIELDS FROM THIS EXPERIMENT DESIGN WERE ANALYZED. THE RESULTS OBTAINED INDICATED THAT CNCS POSSESS A MORPHOLOGY THAT CAN BE DESCRIBED AS INDIVIDUALIZED ROD PARTICLES, WITH AVERAGE DIAMETERS LESS THAN 50 NM AND DIFFERENT SIZE DISTRIBUTION. IN THE ANALYSIS OF CNCS FEATURES, SIGNIFICANT PEARSON CORRELATIONS WERE ESTABLISHED BETWEEN THE CRYSTALLINITY OF THE CNC, CNC YIELD, AND INTERPLANAR CRYSTALLITES DISTANCE (?D/D). THE THERMOGRAVIMETRIC (DTG) PROFILES EXHIBITED TWO CNCS DEGRADATION STAGES, WHERE THE SECOND STAGE CNCS DEGRADATION SHOWED A SIGNIFICATIVE CORRELATION WITH CNC SULFUR CONTENT. IN OUR ANALYSIS, THE CRYSTALLOGRAPHIC PARAMETERS EXHIBITED A CORRELATION WITH THE MECHANICAL BEHAVIOR OF THE CNC, SINCE THE POTENTIAL VARIATION BETWEEN THE DISTANCES OF THE CRYSTALLINE PLANES IS RELATED TO THE STRESS AND DEFORMATION PRESENT IN THE CRYSTALLITES OF CNCS. THIS STUDY PROVIDES NEW KNOWLEDGE REGARDING CNCS, FURTHER ENHANCING INFORMATION FOR CNC-BASED INDUSTRIES AND THE PROCESSABILITY OF CNCS FOR THE DEVELOPMENT OF NEW MATERIALS.

IN THIS STUDY WE REPORT SIGNIFICANT ENHANCEMENT OF UP-CONVERSION EMISSIONS OF LA2O3:ER THIN FILMS WHEN THEY ARE CO-DOPED WITH ER/LN (WHERE LN = ND OR HO). THE PROPOSED MECHANISMS BY WHICH THE LN IONS CONTRIBUTE TO THESE EMISSIONS ARE BASED ON DIFFERENT MECHANISTIC ROUTES. WHILE THE LA2O3 SAMPLES CO-DOPED WITH ER/ND INVOLVES ENERGY TRANSFER NDIII?ERIII PROCESSES, IN THE LA2O3 SAMPLES CO-DOPED WITH ER/HO INVOLVES ENERGY TRANSFER ERIII?HOIII PROCESSES. ALL SAMPLES WERE SYNTHESIZED BY A SOLID STATE PHOTOCHEMICAL DEPOSITION METHOD FOLLOWED BY A SUBSEQUENT CALCINATION PROCESS. THE LUMINESCENT PROPERTIES REVEAL THAT SAMPLES UNDER 980 NM IRRADIATION EXHIBIT CHARACTERISTIC UP-CONVERSION EMISSIONS THAT ARE FOCUSED IN THE GREEN REGION OF THE SPECTRUM AND THAT THE NATURE OF SECOND ACTIVATOR (LN) DETERMINES THE DEGREE OF EFFICIENCY OF THESE EMISSIONS.

CDS:AL THIN FILMS WERE FABRICATED ON A GLASS SUBSTRATE USING THE CBD METHOD. THE EFFECT OF ALUMINUM INCORPORATION ON THE STRUCTURAL, MORPHOLOGICAL, VIBRATIONAL, AND OPTICAL PROPERTIES OF CDS THIN LAYERS WAS INVESTIGATED BY X-RAY DIFFRACTION (XRD), RAMAN SPECTROSCOPY (RS), ATOMIC FORCE MICROSCOPY (AFM), SCANNING ELECTRON MICROSCOPY (SEM), AND UV-VISIBLE (UV-VIS) AND PHOTOLUMINES-CENCE (PL) SPECTROSCOPIES. XRD ANALYSIS OF DEPOSITED THIN FILMS CONFIRMED A HEXAGONAL STRUCTURE WITH A PREFERRED (002) ORIENTATION IN ALL SAMPLES. THE CRYSTALLITE SIZE AND SURFACE MORPHOLOGY OF THE FILMS ARE MODIFIED WITH ALUMINUM CONTENT. RAMAN SPECTRA EXHIBIT FUNDAMENTAL LONGITUDINAL OPTICAL (LO) VIBRATIONAL MODES AND THEIR OVERTONES. OPTICAL PROPERTIES WERE STUDIED FOR EACH THIN FILM. HERE, IT WAS OBSERVED THAT THE OPTICAL PROPERTIES OF THIN FILMS ARE AFFECTED BY THE INCORPORATION OF ALUMINUM INTO THE CDS STRUCTURE.

IN THIS WORK, NI(II) CARBOXYLATE AND GA(III) ?-DIKETONATE COMPLEXES, WERE STUDIED AS PRECURSORS FOR THE PHOTOCHEMICAL DEPOSITION OF TERNARY METAL OXIDE THIN FILMS WITH DIFFERENT LEVELS OF EU(III) DOPING. DILUTED SOLUTIONS OF THESE COMPLEXES WERE MIXED, SPIN-COATED ON SILICON(100) AND IRRADIATED AT ROOM TEMPERATURE WITH A 254 NM UV LIGHT. SUBSEQUENTLY, THE PHOTODEPOSITED FILMS WERE ANNEALED AT 350, 650 AND 950 °C. THE PHOTOCHEMISTRY AND ANNEALING OF THESE FILMS WAS MONITORED BY FOURIER TRANSFORM INFRARED SPECTROSCOPY. THE OBTAINED SAMPLES WERE CHARACTERIZED BY X-RAY DIFFRACTION, X-RAY PHOTOELECTRON SPECTROSCOPY, SCANNING ELECTRON MICROSCOPY AND UV?VIS SPECTROSCOPY. THE RESULTS SHOWED THE FORMATION OF SPINEL-TYPE STRUCTURES (NIGA2O4). THE PREPARED PHOSPHORS UNDER UV IRRADIATION REVEALED RED LUMINESCENCE, WHICH WAS ATTRIBUTED TO TRANSITIONS FROM THE 5D0 EXCITED STATE TO THE 7FJ GROUND STATES OF THE EU3 + IONS. THE INTENSITY OF THE PHOTOLUMINESCENCE DECREASES UPON EU DOPING, AND THE PERFORMANCE OF THESE EMISSIONS DEPENDS STRONGLY ON THE SURFACE STRUCTURE AND MORPHOLOGY OF THE PHOTODEPOSITED FILMS.

AL DOPED AND UNDOPED CDS THIN FILMS (CDS:AL) WERE DEPOSITED ON GLASS, COPPER AND BRONZE SUBSTRATES BY CHEMICAL BATH DEPOSITION TECHNIQUE IN AN AMMONIA-FREE CADMIUM-SODIUM CITRATE SYSTEM. THE STRUCTURAL AND OPTICAL PROPERTIES OF THE CDS FILMS WERE DETERMINED BY X-RAY DIFFRACTION (XRD), SCANNING ELECTRON MICROSCOPE (SEM), AND SIMULTANEOUS TRANSMISSION- REFLECTION SPECTROSCOPY. IT WAS FOUND THAT THE PROPERTIES OF THE FILMS DEPEND ON THE AMOUNT OF AL IN THE GROWTH SOLUTIONS AND DEPOSITION TIME. THE INCREASE IN AL CONTENT IN THE REACTION SOLUTION LED TO A SMALLER CRYSTALLITE SIZE AND HIGHER ENERGY BAND GAP THAT VARIES IN THE RANGE 2.42 EV - 2.59 EV DEPENDING ON THE AL CONTENT.