Weathering of copper-amine treated wood

In this study, the effect of ultraviolet light (UV) irradiation and water spray on color, contact angle and surface chemistry of treated wood was studied. Southern pine sapwood (Pinus Elliottii.Engelm.) treated with copper ethanolamine (Cu-MEA) was subjected to artificially accelerated weathering with a QUV Weathering Tester. The compositional changes and the surface properties of the weathered samples were characterized by Fourier transform infrared (FTIR) spectroscopy, color and contact angle measurements. FTIR indicated that MEA treatment was not found to slow down wood weathering. FTIR spectrum of MEA-treated sample was similar to that of the untreated SP. However, the Cu-MEA treatment retarded the surface lignin degradation during weathering. The main changes in FTIR spectrum of Cu-MEA treatment took place at 915, 1510, and 1595 cm⁻¹. The intensity of the bands at 1510 and 1595 cm⁻¹ increased with the Cu-MEA treatment. Both untreated and MEA-treated exhibited higher ΔE than the Cu-MEA treated samples, indicating that MEA treatment did not retard color changes. However, ΔE decreased with increasing copper concentration, suggesting a positive contribution of Cu-EA to wood color stability. The contact angle of untreated and MEA-treated samples changed rapidly, and dropped from 75 ± 5° to 0° after artificial weathering up to 600 h. Treatment with Cu-MEA slowed down the decreasing in contact angle. As the copper concentration increases, the rate of change in contact angle decreases.     

Surface roughness and color characteristics of wood treated with preservatives after accelerated weathering test

Wood samples treated with ammonium copper quat (ACQ 1900 and ACQ 2200), chromated copper arsenate (CCA), Tanalith E 3491 and Wolmanit CX-8 have been studied in accelerated weathering experiments. The weathering experiment was performed by cycles of 2 h UV-light irradiation followed by water spray for 18 min. The changes on the surface of the weathered samples were characterized by roughness and color measurements on the samples with 0, 200, 400 and 600 h of total weathering.

The objective of this study was to investigate the changes created by weathering on impregnated wood with several different wood preservatives. This study was performed on the accelerated weathering test cycle, using UV irradiation and water spray in order to simulate natural weathering.

Surface roughness and color measurement was used to investigate the changes after several intervals (0–200–400–600 h) in artificial weathering of treated and untreated wood.     

The application of Raman and anti-stokes Raman spectroscopy for in situ monitoring of structural changes in laser irradiated titanium dioxide materials

The use of Raman and anti-stokes Raman spectroscopy to investigate the effect of exposure to high power laser radiation on the crystalline phases of TiO₂ has been investigated. Measurement of the changes, over several time integrals, in the Raman and anti-stokes Raman of TiO₂ spectra with exposure to laser radiation is reported. Raman and anti-stokes Raman provide detail on both the structure and the kinetic process of changes in crystalline phases in the titania material. The effect of laser exposure resulted in the generation of increasing amounts of the rutile crystalline phase from the anatase crystalline phase during exposure. The Raman spectra displayed bands at 144 cm⁻¹ (A1g), 197 cm⁻¹ (Eg), 398 cm⁻¹ (B1g), 515 cm⁻¹ (A1g), and 640 cm⁻¹ (Eg) assigned to anatase which were replaced by bands at 143 cm⁻¹ (B1g), 235 cm⁻¹ (2 phonon process), 448 cm⁻¹ (Eg) and 612 cm⁻¹ (A1g) which were assigned to rutile. This indicated that laser irradiation of TiO₂ changes the crystalline phase from anatase to rutile. Raman and anti-stokes Raman are highly sensitive to the crystalline forms of TiO₂ and allow characterisation of the effect of laser irradiation upon TiO₂. This technique would also be applicable as an in situ method for monitoring changes during the laser irradiation process.     

Surface chemical study on the covalent attachment of hydroxypropyltrimethyl ammonium chloride chitosan to titanium surfaces

An anti-microbial and bioactive coating could not only reduce the probability of infection related to titanium implants but also support the growth of surrounding osteogenic cells. Our previous study has showed that hydroxypropyltrimethyl ammonium chloride chitosan (HACC) with a DS (degrees of substitution) of 18% had improved solubility and significantly higher antibacterial activities against three bacteria which were usually associated with infections in orthopaedics. In the current study, HACC with a DS of 18% coating was bonded to titanium surface by a three-step process. The titanium surface after each individual reaction step was analyzed by X-ray photoelectron spectroscopy (XPS) and attenuated total reflection (ATR) of Fourier-transformed infrared (FT-IR) spectroscopy. The XPS results demonstrated that there were great changes in the atomic ratios of C/Ti, O/Ti, and N/Ti after each reaction step. The XPS high resolution and corresponding devolution spectra of carbon, oxygen, nitrogen, and titanium were also in good coordination with the anticipated reaction steps. Additionally, the absorption bands around 3365 cm⁻¹ (-OH vibration), 1664 cm⁻¹ (Amide I), 1165 cm⁻¹ (ν_as, C-O-C bridge), and the broad absorption bands between 958 cm⁻¹ and 1155 cm⁻¹ (skeletal vibrations involving the C-O stretching of saccharide structure of HACC) verified that HACC was successfully attached to titanium surface.     

Temperature effect on water desorption from methylcellulose films studied by thermal FT-IR microspectroscopy

Temperature-induced desorption behavior of water from methylcellulose (MC) film was investigated by a novel microscopic Fourier transform infrared (FT-IR) spectroscopy equipped with thermal analyzer (thermal FT-IR microscopic system) and thermogravimetric analysis (TGA). The result indicates that the weight loss of water from MC film was markedly correlated to the IR spectral changes of OH stretching (3000-3800 cm⁻¹) and bending (1649 cm⁻¹) modes of water molecules. The shift of OH stretching mode from 3461 to 3481 cm⁻¹ was accompanied with the water loss from MC film induced by temperature effect. Two stages of water desorption from MC film were proposed: the first stage within the 35-65 °C had a dramatic IR peak shift from 3461 to 3477 cm⁻¹ and accompanied with a largest weight loss of water from MC film, which might be mainly due to the desorption of free water with minor weakly hydrogen-bonded water; the second stage beyond 65 °C would be desorption of moderately hydrogen-bonded bound water, due to the gradual IR spectral shift from 3477 to 3481 cm⁻¹ and a slower weight loss of water from MC film. The changes in peak area ratio of 1649 cm⁻¹/1374 cm⁻¹ with the temperature also confirmed the IR spectral peak shift of the OH stretching mode via the water loss from MC film. The temperature-dependent dissociation of intermolecular and intramolecular hydrogen bonds within water molecules and/or between water/MC interaction might be responsible for the desorption kinetics of water from MC film.     

Investigation of the effect of power ultrasound on the nucleation of water during freezing of agar gel samples in tubing vials

Nucleation, as an important stage of freezing process, can be induced by the irradiation of power ultrasound. In this study, the effect of irradiation temperature (−2 °C, −3 °C, −4 °C and −5 °C), irradiation duration (0 s, 1 s, 3 s, 5 s, 10 s or 15 s) and ultrasound intensity (0.07 W cm⁻², 0.14 W cm⁻², 0.25 W cm⁻², 0.35 W cm⁻² and 0.42 W cm⁻²) on the dynamic nucleation of ice in agar gel samples was studied. The samples were frozen in an ethylene glycol-water mixture (−20 °C) in an ultrasonic bath system after putting them into tubing vials. Results indicated that ultrasound irradiation is able to initiate nucleation at different supercooled temperatures (from −5 °C to −2 °C) in agar gel if optimum intensity and duration of ultrasound were chosen. Evaluation of the effect of 0.25 W cm⁻² ultrasound intensity and different durations of ultrasound application on agar gels showed that 1 s was not long enough to induce nucleation, 3 s induced the nucleation repeatedly but longer irradiation durations resulted in the generation of heat and therefore nucleation was postponed. Investigation of the effect of ultrasound intensity revealed that higher intensities of ultrasound were effective when a shorter period of irradiation was used, while lower intensities only resulted in nucleation when a longer irradiation time was applied. In addition to this, higher intensities were not effective at longer irradiation times due to the heat generated in the samples by the heating effect of ultrasound. In conclusion, the use of ultrasound as a means to control the crystallization process offers promising application in freezing of solid foods, however, optimum conditions should be selected.     

Enhanced cell affinity of poly(l-lactide) film by immobilizing phosphonized chitosan

Graft polymerization of acrylic acid (AA) onto poly(l-lactide) (PLLA) film by UV irradiation was carried out to develop surfaces for N-methylene phosphonic chitosan (NMPC) immobilization. The properties of modified films were discussed by colorimetric method, attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR), contact angles, atomic force microscopy (AFM) and osteoblast incubation. The results showed that AA solution concentration and irradiation time had effect on the graft carboxyl densities. Comparing the ATR-FTIR images, two new peaks at 1561 cm⁻¹ and 1632 cm⁻¹ proved that NMPC was immobilized on the film surface successfully. The water contact-angles were decreased from 90 ± 5° to 37 ± 5° after modification. The AFM images indicated that the surface of the combined film was rougher than that of untreated film. The grafted film provided an excellent substrate for the growth of osteoblast.     

Effect of swift (∼100 MeV) heavy ion irradiation on surface morphology and electronic transport in Fe film on Si substrate

Fe film (∼50 nm) have been deposited on pSi substrate by electron beam evaporation technique. The bilayers have been irradiated by 100 MeV Fe⁷⁺ ions having fluences of 1 × 10¹³, 1 × 10¹⁴ and 5 × 10¹⁴ ions cm⁻². SEM study of the unirradiated devices show surface modifications having a annular structures. From XRD study of the bilayer, it is observed that grain size has reduced from 70 to 25 nm after the irradiation for a fluence of 1 × 10¹⁴ ions cm⁻². Moreover electronic transport data of the bilayer show practically no effect on the current flow for a fluence of 1 × 10¹³ ions cm⁻² irradiation whereas for 1 × 10¹⁴ ions cm⁻² fluence, there is very significant change in current flow (by two orders in magnitude) across the bilayer. However, for a higher fluence of irradiation 5 × 10¹⁴ ions cm⁻², the bilayer becomes highly resistive. It has been found from the above observations that the fluence of 1 × 10¹⁴ ions cm⁻² of swift heavy ion irradiation is a optimum fluence.     

Preparation of activated carbons from cherry stones by activation with potassium hydroxide

Using cherry stones, the preparation of activated carbon has been undertaken in the present study by chemical activation with potassium hydroxide. A series of KOH-activated products was prepared by varying the carbonisation temperature in the 400-900 °C range. Such products were characterised texturally by gas adsorption (N₂, −196 °C), mercury porosimetry, and helium and mercury density measurements. FT-IR spectroscopy was also applied. The carbons prepared as a rule are microporous and macroporous solids. The degree of development of surface area and porosity increases with increasing carbonisation temperature. For the carbon heated at 900 °C the specific surface area (BET) is 1624 m² g⁻¹, the micropore volume is 0.67 cm³ g⁻¹, the mesopore volume is 0.28 cm³ g⁻¹, and the macropore volume is 1.84 cm³ g⁻¹.     

Crystallization of 21.25Gd2O3-63.75MoO3-15B2O3 glass induced by femtosecond laser at the repetition rate of 250 kHz

We report the formation of β′-Gd₂(MoO₄)₃ (GMO) crystal on the surface of the 21.25Gd₂O₃-63.75MoO₃-15B₂O₃ glass, induced by 250 kHz, 800 nm femtosecond laser irradiation. The morphology of the modified region in the glass was clearly examined by scanning electron microscopy (SEM). By micro-Raman spectra, the laser-induced crystals were confirmed to be GMO phases and it is found that these crystals have a strong dependence on the number and power of the femtosecond laser pulses. When the irradiation laser power was 900 mW, not only the Raman peaks of GMO crystals but also some new peaks at 214 cm⁻¹, 240 cm⁻¹, 466 cm⁻¹, 664 cm⁻¹ and 994 cm⁻¹which belong to the MoO₃ crystals were observed. The possible mechanisms are proposed to explain these phenomena.     

Local chemical transformations in poly(dimethylsiloxane) by irradiation with 248 and 266 nm

Poly(dimethylsiloxane) (PDMS) has been irradiated with a frequency quadrupled Nd:YAG laser and a KrF^*-excimer laser at a repetition rate of 1 Hz. The analysis of ablation depth versus pulse number data reveals a pronounced incubation behavior. The thresholds of ablation (266 nm: 210 mJ cm⁻², 248 nm: 940 mJ cm⁻²) and the corresponding effective absorption coefficients α_eff (266 nm: 48900 cm⁻¹, 248 nm: 32700 cm⁻¹, α_lin = 2 cm⁻¹) were determined. The significant differences in the ablation thresholds for both irradiation wavelengths are probably due to the different pulse lengths of both lasers. Since the shorter pulse length yields a lower ablation threshold, the observed incubation can be due to a thermally induced and/or a multi-photon absorption processes of the material or impurities in the polymer.Incubation of polymers is normally related to changes of the chemical structure of the polymer. In the case of PDMS, incubation is associated with local chemical transformations up to several hundred micrometers below the polymer surface. It is possible to study these local chemical transformations by confocal Raman microscopy, because PDMS is transparent in the visible. The domains of transformation consist of carbon and silicon, as indicated by the appearance of the carbon D- and G-bands between 1310 and 1610 cm⁻¹, a band appearing between 502 and 520 cm⁻¹ can be assigned to mono- and/or polycrystalline silicon.The ablation products, which are detected in the surroundings of the ablation crater consist of carbon and amorphous SiO_x (x ≈ 1.5) as detected by infrared spectroscopy.     

Effects of swift heavy ion irradiation on the electrical characteristics of Au/n-GaAs Schottky diodes

Metal-semiconductor diode of Au/n-GaAs is studied under the irradiation of swift heavy ion (SHI) beam (80 MeV ¹⁶O⁶⁺), using in situ current-voltage characterization technique. The diode parameters like ideality factor, barrier height, and leakage current are observed to vary with irradiation fluence. Significantly, the diode performance improves at a high fluence of 2 × 10¹³ ions cm⁻² with a large decrease of reverse leakage current in comparison to the original as deposited sample. The Schottky barrier height (SBH) also increases with fluence. At a high irradiation fluence of 5 × 10¹³ ions cm⁻² the SBH (0.62 ± 0.01 eV) is much larger than that of the as deposited sample (0.55 ± 0.01 eV). The diode parameters remain stable over a large range of irradiation up to fluence of 8 × 10¹³ ions cm⁻². A prominent annealing effect of the swift ion beam owing to moderate electronic excitation and high ratio of electronic energy loss to the nuclear loss is found to be responsible for the improvement in diode characteristics.     

Effect of indium doping in CdO thin films prepared by spray pyrolysis technique

Preparation of transparent and conducting indium doped CdO thin films by spray pyrolysis on glass substrate is reported for various concentration of indium (2-8 wt%) in the spray solution. The electrical, optical and structural properties of indium doped CdO films were investigated using different techniques such as Hall measurement, optical transmission, X-ray diffraction and scanning electron microscope. X-ray analysis shows that the undoped CdO films are preferentially orientated along (2 0 0) crystallographic direction. Increase of indium doping concentration increases the films packing density and reorient the crystallites along (1 1 1) plane. A minimum resistivity of 4.843×10⁻⁴ Ω cm and carrier concentration of 3.73×10²⁰ cm⁻³ with high transmittance in the range 300-1100 nm were achieved for 6 wt% indium doping. The band gap value increases with doping concentration and reaches a maximum of 2.72 eV for 6 wt% indium doping from 2.36 eV of that of undoped film. The minimum resistivity achieved in the present study is found to be the lowest among the reported values for In-doped CdO films prepared by spray pyrolysis method.     

Structural and electrical properties of nitrogen and aluminum codoped p-type ZnO films

To resolve the problem of p-type doping in ZnO, nitrogen and aluminum (N-Al) codoped ZnO films were prepared by the ultrasonic spray pyrolysis (USP) technique. The structural and electrical properties of N-Al codoped ZnO films were investigated. The results demonstrate that the undoped ZnO films exhibit the preferential orientation of (002) plane, while ZnO films show high orientation of (101) plane after codoping with N and Al. The N-Al codoped ZnO films under optimum conditions show p-type conduction, with a low resistivity of 1.7×10⁻²Ω cm, carrier concentration of 5.09×10¹⁸ cm⁻³ and high Hall mobility of 73.6 cm² V⁻¹ s⁻¹. A conversion from p-type conduction to n-type was observed during the increase of measurement temperature.     

The effects of xenon ion irradiation on the photoluminesce behavior of poly(p-cresolformaldeyde)/diazonaphtoquinone thin films

In the present paper, we investigate the origin of photoluminescence (PL) and the changes in the optical properties: refractive index and absorption coefficient, in poly(p-cresolformaldeyde) and diazonaphtoquinone thin films irradiated with Xe ions. Films 400 nm thick have been irradiated with 800 keV Xe²⁺ ions in a fluence range from 10¹³ to 6 × 10¹⁵ Xe cm⁻². The structural modifications were followed by the techniques of nuclear reaction analysis, elastic recoil detection analysis, Rutherford backscattering, Fourier transform infrared and Raman spectroscopies. The PL behavior was characterised with 488 nm excitation wavelength. The pristine films show emission with maxima of the main bands located at 635, 720 and 830 nm. For fluences up to 10¹⁴ Xe cm⁻², the photoluminescence intensity increases with the irradiation fluence. The chain mobility lowering, characterized by the crosslinked structure, explains this behavior in organic systems. Other possible contribution for increasing of PL intensity, at these fluences, is the presence of oxygen trapped in the polymer chains by the dangling bonds. At intermediate and higher fluences, the photoluminescence starts to decrease. At fluences higher than 10¹⁴ Xe cm⁻², irreversible changes of the organic structure occur and they are characterized by large losses of oxygen and hydrogen, transforming the material into amorphous carbon films. The loss of photoluminescent behavior is associated with the light absorption characteristics of the amorphous carbon structure. This conclusion is supported by the observed increase of the refractive indexes and absorption coefficients, obtained in the infrared region, as well as by the Raman results. Also, the effect of irradiation modifying the refractive index in the infrared region suggests the application of these films as waveguide in this region of wavelength.     

Characterization of hybrid electrolytes prepared from the Li2S-P2S5 glasses and alkanediols

Inorganic-organic hybrid electrolytes were prepared by the mechanochemical method using the Li⁺ ion conductive 70Li₂S·30P₂S₅ glass and various alkanediols. Local structure of the prepared electrolytes was analyzed by FT-IR and Raman spectroscopy. The effects of the proportion and chain length of alkanediols on conductivity of the hybrid electrolytes were investigated. The hybrid electrolyte with 2 mol.% of 1,4-butanediol exhibited the conductivity of 9.7 × 10^− 5 S cm^− 1 at room temperature and the unity of lithium ion transference number. The use of alkanediols with shorter chain length was effective in increasing conductivity of hybrid electrolytes. The electrolyte using ethyleneglycol showed the highest conductivity of 1.1 × 10^− 4 S cm^− 1 at room temperature. Lowering glass transition temperature by incorporation of alkanediols is responsible for the enhancement of conductivity of hybrid electrolytes.     

Swift ion irradiations of Fe/Fe/Si trilayers

We report here on changes in magnetism and microstructure when implanting, at 92 or 300 K, up to 5 × 10¹⁵ Au²⁶⁺-ions cm⁻² of 350 MeV into ^natFe(45 nm)/⁵⁷Fe(20 nm)/Si trilayers. This choice of ions and energy allowed to test the irradiation effects in the regime of pure electronic stopping. The samples were analysed before and after irradiation by Rutherford back-scattering spectroscopy, X-ray diffraction, conversion electron Mössbauer spectroscopy, and magneto-optical Kerr effect. Up to 1 × 10¹⁵ ions cm⁻², there was interface broadening at a mixing rate of Δσ²/Φ = 55(5) nm⁴, followed by full Fe-Si inter-diffusion. The Mössbauer spectra revealed fractions of α-Fe and amorphous ferromagnetic and paramagnetic iron silicides, but no crystalline Fe-Si phase. The magnetic remanence in the as-deposited Fe-layer showed small components of uniaxial and four-fold magnetization. For increasing ion fluence, the component with four-fold symmetry grew at the expense of the uniaxial component. For the highest fluences, an isotropic magnetization was found.     

Growth and characteristics of hydrogenated In-doped ZnO thin films by pulsed DC magnetron sputtering

We investigated the role of hydrogen impurities in highly oriented In-doped ZnO (IZO:H) films. The conductivity of ZnO:H films exhibit small variation despite the increase of hydrogen ratio. The small variation of the carrier concentration in IZO:H films can be explained by the reduction of the oxygen deficiency for the charge neutrality and the increase of Vzn-H bonding for partially charge compensation in the films. The additional mode at 573 cm⁻¹ is interpreted as vacancy clusters. The discrepancy between the increase of vacancy clusters (573 cm⁻¹) and small variation of carrier concentration is attributed to the different physical characteristics of the IZO:H films due to the hydrogen existence between bulk and surface. The measured FT-IR peak at 3500 cm⁻¹ exhibits typical characteristic of O-H bonding.     

High level compressive residual stresses produced in aluminum alloys by laser shock processing

Laser shock processing (LSP) has been proposed as a competitive alternative technology to classical treatments for improving fatigue and wear resistance of metals. We present a configuration and results for metal surface treatments in underwater laser irradiation at 1064 nm. A convergent lens is used to deliver 1.2 J/cm² in a 8 ns laser FWHM pulse produced by 10 Hz Q-switched Nd:YAG, two laser spot diameters were used: 0.8 and 1.5 mm.Results using pulse densities of 2500 pulses/cm² in 6061-T6 aluminum samples and 5000 pulses/cm² in 2024 aluminum samples are presented. High level of compressive residual stresses are produced −1600 MPa for 6061-T6 Al alloy, and −1400 MPa for 2024 Al alloy. It has been shown that surface residual stress level is higher than that achieved by conventional shot peening and with greater depths. This method can be applied to surface treatment of final metal products.     

Quantitative measurement of integrated band intensities of benzene vapor in the mid-infrared at 278, 298, and 323 K

Pressure broadened (1 atm. N₂) laboratory spectra of benzene vapor (in natural abundance) were recorded at 278, 298, and 323 K, covering 600-6500 cm⁻¹. The spectra were recorded at a resolution of 0.112 cm⁻¹ using a commercial Fourier transform spectrometer. The pressure of each benzene vapor sample was measured using high-precision capacitance manometers, and a minimum of nine sample pressures were recorded for each temperature. The samples were introduced into a temperature-stabilized static cell (19.94(1) cm pathlength) that was hard-mounted into the spectrometer. From these data a fit composite spectrum was calculated for each temperature. The number density for the three composite spectra was normalized to 296 K. The spectra give the absorption coefficient (cm² molecule⁻¹, naperian units) as a function of wavenumber. From these spectra integrated band intensities (cm molecule⁻¹ and atm⁻¹ cm⁻²) for intervals corresponding to the stronger benzene bands were calculated and were compared with previously reported values. We discuss and quantify error sources and estimate our systematic (NIST Type-B) errors to be 3% for the stronger bands. The measured absorption coefficients and integrated band intensities are useful for remote sensing applications such as measurements of planetary atmospheres and assessment of the environmental impact of terrestrial oil fire emissions.