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Wood‐based materials such as composites or laminates play an important role in today's furniture industry, especially in manufacturing high‐quality kitchen and dining room furniture. One important aspect after fabrication is the investigation of these materials to derive quality metrics such as surface stain and scuff resistance. Current sample preparation methods are mostly straightforward and rely on cutting and grinding the materials under test, including sensitive wood substrates. To investigate cross‐sections and different layer topologies, characterisation techniques such as atomic force microscopy (AFM) and infrared (IR) microscopy are of potential interest. However, a huge limitation is that current sample preparation methods lead to smeared coatings on the sample cross‐sections and high surface roughness. Hence, these methods are not applicable for the sample preparation in measuring AFM and IR microscopy. Therefore, new preparation techniques need to be developed accordingly. This article presents a new approach towards coated wood‐based sample preparation including embedding processes to use those samples for AFM and IR microscopy technologies. The proposed method has been evaluated by obtaining AFM, IR and microscopy measurements of more than four different wood‐based samples such as (i) raw paper, (ii) impregnated paper, (iii) melamine‐coated chipboards and (iv) medium‐density fibreboards. The investigation results showed a significant improvement in sample preparation, as well as clear chemical and physical characterisation over whole sample construction, including coating layers, for wood‐based materials. [ABSTRACT FROM AUTHOR]

The purpose of the present study is to offer an optimal model to predict the tensile index of the paper being consumed to make veneer impregnated with different weight ratios of modified starch (from 3.18 to 36.8%) to urea formaldehyde resin (WR) containing different formaldehyde to urea molar ratios (MR, from 1.16:1 to 2.84:1) enriched by different contents of silicon nano-oxide (NC, from 0 to 4%) using multiple linear regression (MLR) and adaptive neuro-fuzzy inference system (ANFIS) and compare the precision of these two models to estimate the response being examined (tensile index). Fourier-transform infrared spectroscopy (FTIR) and transmittance electron microscopy (TEM) were also used to analyze the results. The results of studying the adhesive structure using FTIR analysis showed that as the WR increased to the maximum level and MR increased to the average level (3%), more ether and methylene linkage forms due to cross-linking. TEM analysis also indicated that if an average level of silicon nano-oxide is applied, there will be more cross-linking due to the more uniform distribution and suitable interactions between the adhesive and nanoparticles. The modeling results showed that the ANFIS model estimates have been closer to the actual values compared to the MLR model. It can be concluded that the model offered by ANFIS has a higher potential to predict the tensile index of the paper impregnated with the combined adhesive of UF resin and modified starch. However, the MLR model could not offer a good estimate to predict the response. According to the preferred approach to predict the most effective property of resin coated paper, modelling would be useful to the research community and the results are beneficial in industrial applications without spending more cost and time. [ABSTRACT FROM AUTHOR]

In order to further improve the performance of impregnated paper decorated blockboard (ecological board), high-density fiberboard (HDF) was selected as the equilibrium layer to replace the commonly used poplar veneer. Results showed that the performance of HDF ecological board can be comparable to that of poplar veneer ecological board. It had good appearance quality, and its surface scratch resistance, surface wear resistance, water resistance and mechanical properties met the requirements of National Standard GB/T 34722-2017. The surface cracking resistance of the ecological board prepared with HDF as the equilibrium layer reached the highest level (grade 5), far better than that of the poplar veneer ecological board. This was because HDF was a relatively homogeneous material, and its dry shrinkage in both the transverse direction and along the grain direction was much lower than that of the poplar veneer. This characteristic of HDF made it possible to improve the dimensional stability and bending resistance of blockboard substrates under dry and hot conditions. The formaldehyde emission of the HDF ecological board was higher than that of the poplar veneer ecological board, but it met the formaldehyde emission requirements of indoor materials according to GB 18580-2001. [ABSTRACT FROM AUTHOR]

In this work, we present an experimental study on electrical breakdown, also called dielectric failure on a material widely used as insulation in oil transformers and other equipment. This material is pressboard paper impregnated with insulating oil. The breakdown tests are carried out under three types of voltage and for several voltage rise speeds. Dielectric breakdown is a random phenomenon, many tests are carried out on a large number of samples and the results obtained have been subjected to statistical processing. The material is cut into square plates of 7.5 cm in length from a set of plates 2 m² in length and 500 µm in thickness. Prior to the tests, the samples were conditioned in a desiccator with silicone gel for at least 24 hours in order to eliminate any presence of moisture. Then they were impregnated with Borak22 insulating oil for at least one week. The tests consist of placing the sample concerned between two cylindrical bronze electrodes and applying a voltage ramp at constant speed until breakdown. After failure, the value of the breakdown voltage is taken. These tests are carried out in the laboratory at room temperature. However, we have tried to reproduce the same conditions for all the tests. These various tests relate to the effect of the form and the rate of rise of the applied voltage on the dielectric strength of the pressboard paper impregnated with Borak22 insulating oil. Two measuring devices were used, and the tests were carried out under three voltage forms: sinusoidal alternating current, continuous positive polarity, and continuous negative polarity, and at eight different voltage ramp speeds: 0,69; 1,07; 1,4; 1,89; 2,38; 2,94; 3,28 and 4, 17 kV/s. For each measurement point, 35 samples of pressboard paper are used and tested. A total of 840 results we re obtained and processed using the two-parameter Weibull statistical model. In order to validate this model, these results are subjected to a Kolmogorov-Smirnov adequacy test and are framed by 95% confidence bands. The maximum likelihood method is used for the estimation of the Weibull parameters and the smoothing of the experimental points. The results of the statistical tests on the breakdown voltage measurement points obtained confirm the use of the two-parameter Weibull model. The evolution of the nominal breakdown voltage as a function of the voltage ramp of the three forms of applied voltage gives three properties of the same form, which is akin to the letter 'S'. The breakdown voltage first increases linearly for low speeds, then increases and takes an exponential form for medium speeds, then tends towards a certain saturation for high speeds. The breakdown voltage under the DC voltage ramp is higher than the voltage obtained for the AC voltage ramp and are higher under negative polarity voltage than those under positive polarity voltage. [ABSTRACT FROM AUTHOR]

The surface properties of melamine-urea-formaldehyde (MUF) impregnated paper decorative panels are unsatisfactory, characterized by brittle surfaces, poor abrasion resistance, and limited flame retardancy. A modification was introduced to the MUF resin by incorporating a blend of polyelectrolyte complex polyethyleneimine (PEI)-phytic acid (PA) and Nano-Al 2 O 3 with the aim of enhancing the surface properties of the decorative panel. The modified resin underwent characterization, and subsequent analyses were conducted to investigate the properties of both the modified impregnated paper and the decorative panel. The results showed that the thermal stability of the modified resin was improved with a curing temperature of 124 °C. In comparison to the control, the modified impregnated paper showed an increase of 146.0 % in tensile strength and 154.5 % in elongation at break. The improved toughness of the modified MUF-impregnated paper resulted in a notable upsurge in both surface bond strength and cracking resistance of the decorative panel. The combustion test results indicated that the modified impregnated had a LOI value of 40.0 % and self-extinguishing behavior. In addition, due to the inclusion of Nano-Al 2 O 3 , the decorative panel exhibited a low abrasion value of only 14.1 mg/100r. Overall, the technology proposed in this study can improve the surface properties of decorative panels, increase their added value, and provide a new strategy for modifying MUF resin in the impregnated paper-decorated wood-based panels industry and for researchers. [Display omitted] • MUF resin was modified using polyelectrolyte complex (PEI-PA) and Nano-Al 2 O 3. • Modified impregnated paper exhibited superior toughness and flame retardancy. • Blockboard with modified impregnated paper showed greatly improved surface properties. [ABSTRACT FROM AUTHOR]

The purpose of the present study is to offer an optimal model to predict the tensile index of the paper being consumed to make veneer impregnated with different weight ratios of modified starch (from 3.18 to 36.8%) to urea formaldehyde resin (WR) containing different formaldehyde to urea molar ratios (MR, from 1.16:1 to 2.84:1) enriched by different contents of silicon nano-oxide (NC, from 0 to 4%) using multiple linear regression (MLR) and adaptive neuro-fuzzy inference system (ANFIS) and compare the precision of these two models to estimate the response being examined (tensile index). Fourier-transform infrared spectroscopy (FTIR) and transmittance electron microscopy (TEM) were also used to analyze the results. The results of studying the adhesive structure using FTIR analysis showed that as the WR increased to the maximum level and MR increased to the average level (3%), more ether and methylene linkage forms due to cross-linking. TEM analysis also indicated that if an average level of silicon nano-oxide is applied, there will be more cross-linking due to the more uniform distribution and suitable interactions between the adhesive and nanoparticles. The modeling results showed that the ANFIS model estimates have been closer to the actual values compared to the MLR model. It can be concluded that the model offered by ANFIS has a higher potential to predict the tensile index of the paper impregnated with the combined adhesive of UF resin and modified starch. However, the MLR model could not offer a good estimate to predict the response. According to the preferred approach to predict the most effective property of resin coated paper, modelling would be useful to the research community and the results are beneficial in industrial applications without spending more cost and time.

In order to further improve the performance of impregnated paper decorated blockboard (ecological board), high-density fiberboard (HDF) was selected as the equilibrium layer to replace the commonly used poplar veneer. Results showed that the performance of HDF ecological board can be comparable to that of poplar veneer ecological board. It had good appearance quality, and its surface scratch resistance, surface wear resistance, water resistance and mechanical properties met the requirements of National Standard GB/T 34722-2017. The surface cracking resistance of the ecological board prepared with HDF as the equilibrium layer reached the highest level (grade 5), far better than that of the poplar veneer ecological board. This was because HDF was a relatively homogeneous material, and its dry shrinkage in both the transverse direction and along the grain direction was much lower than that of the poplar veneer. This characteristic of HDF made it possible to improve the dimensional stability and bending resistance of blockboard substrates under dry and hot conditions. The formaldehyde emission of the HDF ecological board was higher than that of the poplar veneer ecological board, but it met the formaldehyde emission requirements of indoor materials according to GB 18580-2001.

This paper is an experimental study of the electrical conduction of mineral-oil/solid interfaces in negative polarity. This study is performed in a point-plane configuration immersed in mineral oil submitted to impulse voltages. The interface is assembled with an inclined solid in contact with the point electrode tip. Charge recordings and conduction currents of different combinations of mineral-oil/solid interfaces are reported. Different polymers and oil-impregnated papers are used as the solid materials. It is found that for voltages lower than the inception voltage, the injection of charge belongs to a weak injection regime. The spatial limitation with solids of similar permittivity as the mineral oil decreases the charge injection. The charge injection at mineral-oil/solid interfaces follow two conduction current type characteristics. Experiments with mineral-oil/PTFE interface shows the existence of a transition between both conduction current types if the applied voltage is increased. [ABSTRACT FROM AUTHOR]

Novel psychoactive substances (NPS) in the form of impregnated papers delivered to prisoners are of particular concern in prison settings, where they are commonly used by vaping. The purpose of this study was to create a qualitative method for identifying the various emerging NPS impregnated onto paper samples sent to prisoners. It helps to demonstrate that these findings can be used to predict drug prevalence and trends in prisons. Between 2018 and 2020, 1250 non-judicial paper samples seized from 12 English prisons were analysed to determine the NPSs being circulated. Approximately 1 cm2 paper were cut and added to 50 % (v/v) methanol in LCMS-grade water. Vortex-mixing was used to prepare extracts (30 min). Q-TOF LC/MS was used to screen the extracts. This study showed that synthetic cannabinoid receptor agonist (SCRA) was the most common drug group detected in impregnated paper seizures in English prisons between 2018 and 2020, followed by cocaine, heroin type drugs (A) and amphetamine, ketamine type drugs (B). Male prisons had a higher prevalence of SCRAs, whereas female prisons had a higher prevalence of A drugs. Furthermore, lower security prisons were found to have a higher prevalence of B drugs, pregabalin, gabapentin type drugs (C), and abused and prescription drugs than higher security prisons which unveiled a higher prevalence of nicotine. The findings of this study have revealed new information about drug use in prisons. This study will also aid in the identification of drug smuggling routes into jails, keeping prison staff up to date with the trends. • SCRA was the most prevalent drug group detected in drug-impregnated papers. • SCRAs had higher prevalence in male prisons, wheareas female prisons presented higher prevalence of Class A drugs. • Lower security level prisons had higher prevalence of Class B, Class C drugs compared to higher security level prisons. [ABSTRACT FROM AUTHOR]

This study was carried out in order to investigate the effects of different types of resins and also their mixtures on the impregnated paper properties. In this regard, pure urea resin (100%), mixture of melamine and urea resins with various combinations (60/40 and 70/30 and 50/50), mixture of nano-fiber cellulose ratios of 1, 2 and 3 percent with urea resin and pure PVA (100%) were used to impregnate of newsprint basic paper of Mazandaran wood and paper industries. Immersion of samples in the impregnation step were done in two time of 5 and 10 seconds. Next, melamine resin was used for surface coating and then absorption of resin in the impregnation and coating process measured. Results showed that in the impregnation step with pure urea (100%), in the respect of absorption rate and surface properties of melamine paper, the best time of impregnation was obtained 10 seconds. In the combined treatment, adding up to 30% melamine to urea resin, as impregnation step resin, offers better properties in terms of stain resistance, cigarette resistance, resistance to cracking and resistance to hot water steam for impregnatedmade paper. By adding nanocellulose up to 1% in impregnation resin, better properties is obtained for melamine paper. Also, PVA as impregnation resin, can be offer similar quality to pure urea in the resulting melamine papers.

Ethylene glycol and caprolactam were added during the synthesis process of melamine formaldehyde (MF) resins to develop a new MF formulation with high flexibility, storage stability, and low formaldehyde emissions that can be used for the impregnation of papers. It was demonstrated that the MF resins with amounts of ethylene glycol (molar ratio of ethylene glycol to melamine was 1.0) and caprolactam (molar ratio of caprolactam to formaldehyde was 0.12) achieved higher storage stability, flexibility, and lower free formaldehyde content. The impregnated papers made from these MF resins displayed good dry and wet tensile strength and passed the relevant standard specifications for decorative paper on wood-based panels. The size exclusion chromatography (SEC) and Fourier transform-infrared spectrometry (FT-IR) studies showed that the MF resins produced via incorporation of ethylene glycol and caprolactam had a different molecular weight distribution and polymeric structure. [ABSTRACT FROM AUTHOR]

This paper systematically studies the effect of Fe3O4 nanoparticle size on the insulation performance of nanofluid impregnated paper. Three kinds of Fe3O4 nanoparticles with different sizes and their nanofluid impregnated papers were prepared. Environmental scanning electron microscopy (ESEM) and infrared spectroscopy were used to analyze the combination of Fe3O4 nanoparticles and nanofluid impregnated paper. The effect of nanoparticle size on breakdown voltage and several dielectric characteristics, e.g., permittivity, dielectric loss, of the nanofluid impregnated paper were comparatively investigated. Studies show that the Fe3O4 nanoparticles were bound to impregnated paper fibers by O–H bonds, while the relative permittivity and dielectric loss of the nanofluid impregnated papers were increased. Meanwhile, the increase of trap depth, caused by the nanoparticles, can trap the electric charge and improve the breakdown strength. The test results show that the direct current (DC) and alternating current (AC) breakdown voltages of nanofluid impregnated paper increased by 9.1% and 10.0% compared to FR3 nanofluid impregnated paper, respectively.

Formaldehyde-free liquid adhesives derived from biomass are attractive candidates to petroleum-based counterparts. However, developing solid bio-adhesive with excellent wet strength and bonding performances remains a lasting challenge. Here, we report a bio-composite sheet consisting of soybean flour, paper, and cross-linking agent (Polyamidoamine-epichlorohydrin, PAE), and its wet strength and bonding performances was evaluated by paper straw and plywood application. The covalent crosslinking by the reaction of soybean protein and PAE plays a major role in the enhancement of various properties of the cured bio-composite sheet. The tensile stress of cured bio-composite sheet was only lower than the prototype sample 14.5% after 100 ℃ water soaking treatment for 2 h. Paper straw rolled from the bio-composite sheet displayed boiling water stable at the same condition, while had better flexural strength and natural degradability than the plastic straw. Bonding strength of plywood boned with bio-composite sheet reached 1.38 MPa, which was exceeded 97.1% than the requirement of the Chinese National Standard GB/T 9846–2015 for interior plywood. Given the simple and general strategy, the products based on bio-composite sheet can potentially be a new approach on the use of biomass adhesives, which also be a suitable solution to solve the environmental challenges (e.g., formaldehyde) in the field of biomass-based composites. • An eco-friendly bio-composite sheet was fabricated by a 'green' approach. • The bio-composite sheet displays excellent wet bonding performance. • The cured bio-composite sheet has excellent mechanical and wet strength. • The resultant paper straws show high hydrostability and natural degradability. • The resultant plywood can meet the requirements for interior application. [ABSTRACT FROM AUTHOR]

Modern bioplastics and biocomposites frequently contain non-biodegradable or non-sustainable components and require complex recycling routes. Sustainable materials require integrating bio-based, cheap, widely available, recycled, or waste components. In order to incorporate these concepts, we selected hemp stalk waste, the industrial byproducts glycerol and xylan (hemicellulose), and citric acid as key components. Hemp stalks were processed into cast papers using only mechanical processes and no chemical modifications or pre-treatments. Cast papers were impregnated with a crosslinking mixture of glycerol, xylan, citric acid, and the plasticizer polyethylene glycol (PEG). Thermal crosslinking was performed as a single-step reaction by curing materials at 140 °C. All prepared bioplastics were washed in water for 48 h and extensively tested for water resistance and water absorption. A recycling route with depolymerization (for pulp recovery) in sodium hydroxide is demonstrated. A comprehensive analysis of crosslinking reaction is provided via FTIR and rheology, supplemented by structure analysis via SEM. A 7-fold reduction in water uptake was achieved compared to cast hemp paper. Obtained bioplastics, after washing in water, show elastic modulus up to 2.9 GPa, tensile strength up to 70 MPa, and elongation up to 4.3 %. As a result of component ratio variation, bioplastics achieve a high tuneability of properties ranging from brittle to ductile. Dielectric analysis indicates that bioplastics have the potential for application in electric insulation. A three-layer laminate is demonstrated as a concept for potential application as an adhesive for bio-based composites. • Bioplastics with excellent mechanical performance and water resistance • Tuneable structure and properties • Integrates a circular approach and recycling • Can be applied as an adhesive for biocomposites [ABSTRACT FROM AUTHOR]

A simple field method for determination of fluoride in drinking water using handmade fluoride reagent paper impregnated by aluminium quinalizarin complex was developed. Fluoride reacts with the impregnated reagent paper to release the free ligand with new colour, orange different from that of the complex. The change in the colour, which is proportional to the amount of fluoride, was measured by the Arsenator. The functionality of the Arsenator which is based on a photometric measurement of spot on the reagent paper is expanded to analyse fluoride. The method allows a reliable determination of fluoride in the range 0.0–2.0 mg L−1. Further spectrophotometric determinations of fluoride showed that Beer’s law is obeyed in the range of 0.3–5.0 mg L−1 at 553 nm. Sensitivity, detection limit, quantitation limit, and the percentage recovery of 1.5 mg L−1 fluoride were found to be 0.117 μg mL−1, 0.1 mg L−1, 0.3 mg L−1, and 101.2 respectively.

Objective: To determine the efficacy of WHO impregnated paper and CDC coated bottle based on number of storage days and number of times of consecutive use, in the assessment of insecticide vector susceptibility tests in laboratory and field conditions. Methods: Larvae and pupae of Anopheles gambiae s.l. mosquitoes were collected from the breeding sites in Seme-Kpodji and Cotonou districts in Southern Benin in April 2013 during the first rainy season. Anopheles gambiae s.l. mosquitoes were also collected from the breeding sites in Parakou district in Northern Benin in May 2013 at the beginning of the rainy season. Susceptibility tests were done using impregnated paper with bendiocarb (0.1%) following WHO protocol and stock solutions of permethrin (21.5 μg per bottle) and deltamethrin (12.5 μg per bottle) following CDC protocol on unfed female mosquitoes aged 2-5 days old. These bioassays were repeated a certain number of times. The temperature and relative humidity were monitored and recorded during the susceptibility tests. Results: This study showed that a WHO impregnated paper with bendiocarb could be used four times during four consecutive days in field conditions. Regarding a Wheaton coated bottle with permethrin or deltamethrin, they could be used at least three times during four consecutive days in laboratory conditions. Conclusions: The day storage and the number of times that a WHO impregnated paper and a CDC coated bottle maintained their efficacy are useful in the assessment of insecticide vectors susceptibility tests.

This document presents an experimental study on the propagation of first mode negative streamers along mineral oil-solid interfaces. Samples made of an oil impregnated kraft paper and a low-porosity paper made from cellulosic micro and nano fibrils, as well as different polymeric films (low density polyethylene (LDPE), polyethylene terephthalate (PET), polytetrafluoroethylene (PTFE) and polyvinylidene fluoride (PVDF)) are used as the solid. A comparison of the length, charge and velocity of streamers for all different mineral oil-solid interfaces is reported. It is shown that streamers propagate longer and faster along mineral oil-solid interfaces with low surface roughness, low porosity and higher electrical permittivity than mineral oil. Those streamers show a quasi-continuous injection of charge in the early stage of their propagation. This quasi-continuous charge injection consists of a sequence of small charge steps separated by few tens of nanoseconds in between. In comparison, the streamers that propagate along surfaces with similar permittivity to the mineral oil have lower injection of charge and higher stopping voltage conditions than streamers propagating free in the liquid without any solid barrier. [ABSTRACT FROM AUTHOR]

Melamine–formaldehyde (MF) resin-impregnated paper-decorated panels are prone to surface cracking, which can be reduced by changing the brittle structure of the MF resin. To increase the curing degree and toughness of the resin, a hexamethylene diisocyanate trimer blocked with methyl ethyl ketoxime (ME-HDI-tri) was used as a temperature-responsive crosslinker. This latent crosslinking agent only worked above 120 °C, which prevented it from participating in cross-linking reactions during the preparation of the impregnated paper. The chemical structures of the modified MF resins (ME-HDI-tri-MF) were characterized by Fourier-transform infrared (FTIR) spectroscopy. The curing behaviors of the MF resins were characterized by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and dynamic mechanical thermal analysis (DMTA). Impregnated paper was prepared with ME-HDI-tri-MF, and its tensile strength and elongation at break were tested. Blockboard was prepared with ME-HDI-tri-MF, and its cracking and corrosion resistance were tested. The absorption peak of the methylene chain was observed in the FTIR spectrum of ME-HDI-tri-MF after curing, which indicated that ME-HDI-tri participated in the curing reaction of the MF resin. With the addition of ME-HDI-tri 5 %, the curing temperature of the MF resin decreased from 142 °C to 130 °C, and the ultimate tensile stress and elongation at break of the modified impregnated paper increased by 97.70 % and 86.25 %, respectively. The cracking and corrosion resistance of the decorated panel prepared with ME-HDI-tri-MF were also improved. After adding 3 % ME-HDI-tri, the surface cracking of the decorated panels was prevented, which extended the service life and broadened the application range of the decorated panels. [Display omitted] • Temperature-responsive crosslinker adjusted the curing behavior of melamine-formaldehyde (MF) resins. • The toughness of MF resin-impregnated paper was improved. • The surface cracking and corrosion resistance of decorated blockboard was enhanced. [ABSTRACT FROM AUTHOR]

Objective To determine the efficacy of WHO impregnated paper and CDC coated bottle based on number of storage days and number of times of consecutive use, in the assessment of insecticide vector susceptibility tests in laboratory and field conditions. Methods Larvae and pupae of Anopheles gambiae s.l. mosquitoes were collected from the breeding sites in Seme-Kpodji and Cotonou districts in Southern Benin in April 2013 during the first rainy season. Anopheles gambiae s.l. mosquitoes were also collected from the breeding sites in Parakou district in Northern Benin in May 2013 at the beginning of the rainy season. Susceptibility tests were done using impregnated paper with bendiocarb (0.1%) following WHO protocol and stock solutions of permethrin (21.5 μg per bottle) and deltamethrin (12.5 μg per bottle) following CDC protocol on unfed female mosquitoes aged 2-5 days old. These bioassays were repeated a certain number of times. The temperature and relative humidity were monitored and recorded during the susceptibility tests. Results This study showed that a WHO impregnated paper with bendiocarb could be used four times during four consecutive days in field conditions. Regarding a Wheaton coated bottle with permethrin or deltamethrin, they could be used at least three times during four consecutive days in laboratory conditions. Conclusions The day storage and the number of times that a WHO impregnated paper and a CDC coated bottle maintained their efficacy are useful in the assessment of insecticide vectors susceptibility tests. [ABSTRACT FROM AUTHOR]

A simple field method which allows the determination of fluoride in drinking water with a small handheld instrument called Arsenator was developed. Arsenator is a commercially available instrument which was used successfully for reliable determination of arsenic. In the proposed method the functionality of the Arsenator which is based on a photometric measurement of a spot on the reagent paper is expanded to analyse fluoride. A polymeric aluminium complex of 5-(2-carboxyphenylazo)-8-hydroxyquinoline (LH2) has been prepared as a new specific reagent for fluoride. Job's method of continuous variation was adopted for the determination of the composition of the coloured complex, which was further characterized by UV-VIS spectroscopic studies. The molar absorptivity of the complex formation is 8.48 × 103 L mol−1 cm−1at 410 nm. The coloured complex reacts with fluoride on an impregnated paper where its colour changes are dependent on the concentration of fluoride in water samples. The change in the colour was measured using the Arsenator. The method allows a reliable determination of fluoride in the range 0.3 to 2.0 mg L−1. Further spectophotometric determinations of fluoride in drinking water were also studied. The determination is based on the reaction of aluminium complex with fluoride in the examined samples. Beer's law is obeyed in the range 0.3 to 2.0 mg L−1of fluoride at 495 nm. Sensitivity, detection limit and quantitation limit of the method were found to be 0.251 ± 0.007 µg−1 mL, 0.1 mg L−1and 0.3 mg L−1, respectively. The optimum reaction conditions and other analytical conditions were evaluated. The effect of interfering ions on the determination is described. There is no interference by nitrate or chloride. Sulphate interfered only at high concentrations which are not expected in drinking water. [ABSTRACT FROM PUBLISHER]

Abstract: Two organic–inorganic hybrid sol–gel coatings were developed in order to modify the surface energy and moisture behaviour of the commercial impregnated paper. The surface characteristics of the paper samples were studied by scanning electron microscopy (SEM), confocal laser scanning microscopy (CLSM), atomic force microscopy (AFM), attenuated total reflectance Fourier transform infrared spectrometry (ATR-FTIR), X-ray photoelectron spectroscopy (XPS) and time of flight secondary ion mass spectroscopy (ToF-SIMS). It was found that the applied sol–gel coatings as well as the curing process changed the surface structural and chemical properties of the impregnated paper. The chemical bonding between the hydroxyl groups present on paper surface and silanol groups from sol–gel coatings was confirmed by the FTIR spectra. The measured surface energies divided into polar and dispersive components indicated that the coating B resulted in less polar surface than did the coating A which was more polar than the reference (the impregnated paper with water and heat treatment). Coating B brought about the lowest total surface energy. It was obtained that the water repellence of the impregnated paper was improved by both coatings and the curing process. [Copyright &y& Elsevier]

Formaldehyde emission is an intrinsic property derived from aldehyde-based resin that is used in wood-based composites. To reduce formaldehyde emission from plywood, the composite catalyst of tourmaline-titanium dioxide (T-TiO 2) was fabricated by the sol-gel method. Furthermore, the impregnated paper loaded with the T-TiO 2 composite catalyst was used to decorate the surface of 5-layer poplar plywood. The physicochemical structure, photocatalytic activity of T-TiO 2 composite catalyst and its mechanism of degrading gaseous formaldehyde and generating air negative ions were assessed. The results discovered that the synergistic influence of the tourmaline and TiO 2 anatase nanocrystals achieved good photodegradation of the gaseous formaldehyde. The neat T(20%)-TiO 2 catalyst offered a higher formaldehyde removal efficiency (92.2%) than other catalysts, possessing 800 ions/cm3 of air negative ions concentration after 10-h visible light irradiation. The poplar plywood with a load of 3% T(20%)-TiO 2 catalyst can stably induce the degradation formaldehyde into air negative ions with a concentration of 1200 ions/cm3 in visible light. The impregnation process of paper was feasible to be industrialized and the decorated wood-based composites can be widely applied in the furniture industry. [Display omitted] • Tourmaline-titanium dioxide with dual-function was prepared by a sol-gel method. • Formaldehyde removal efficiency reaches more than 90% by visible light irradiation. • Achieved versatility decorative plywood: convert formaldehyde into air negative ions. • Air negative ions concentration of the plywood product reaches 1200 ions/cm3. • Dual-functional decorative panel shows great potential in producing interior materials. [ABSTRACT FROM AUTHOR]

This paper systematically studies the effect of Fe3O4 nanoparticle size on the insulation performance of nanofluid impregnated paper. Three kinds of Fe3O4 nanoparticles with different sizes and their nanofluid impregnated papers were prepared. Environmental scanning electron microscopy (ESEM) and infrared spectroscopy were used to analyze the combination of Fe3O4 nanoparticles and nanofluid impregnated paper. The effect of nanoparticle size on breakdown voltage and several dielectric characteristics, e.g., permittivity, dielectric loss, of the nanofluid impregnated paper were comparatively investigated. Studies show that the Fe3O4 nanoparticles were bound to impregnated paper fibers by O–H bonds, while the relative permittivity and dielectric loss of the nanofluid impregnated papers were increased. Meanwhile, the increase of trap depth, caused by the nanoparticles, can trap the electric charge and improve the breakdown strength. The test results show that the direct current (DC) and alternating current (AC) breakdown voltages of nanofluid impregnated paper increased by 9.1% and 10.0% compared to FR3 nanofluid impregnated paper, respectively. [ABSTRACT FROM AUTHOR]

A simple field method for determination of fluoride in drinking water using handmade fluoride reagent paper impregnated by aluminium quinalizarin complex was developed. Fluoride reacts with the impregnated reagent paper to release the free ligand with new colour, orange different from that of the complex. The change in the colour, which is proportional to the amount of fluoride, was measured by the Arsenator. The functionality of the Arsenator which is based on a photometric measurement of spot on the reagent paper is expanded to analyse fluoride. The method allows a reliable determination of fluoride in the range 0.0–2.0 mg L −1 . Further spectrophotometric determinations of fluoride showed that Beer’s law is obeyed in the range of 0.3–5.0 mg L −1 at 553 nm. Sensitivity, detection limit, quantitation limit, and the percentage recovery of 1.5 mg L −1 fluoride were found to be 0.117 μg mL −1 , 0.1 mg L −1 , 0.3 mg L −1 , and 101.2 respectively. [ABSTRACT FROM AUTHOR]