Properties of fast-growing poplar wood simultaneously treated with dye and flame retardant

Simultaneous dyeing and inflaming retarding treatment improves both the aesthetic aspects and the safety value of fast-growing tree species. This study investigated the effects of water bath temperature, dye concentration, flame retardant concentration and dipping time on dye uptake and limited oxygen index of simultaneously dyed and fire-retardant-treated wood veneer. Through comprehensive analysis, an improved process was obtained and wood with these improved properties was prepared. Analyses of chemical structure and thermal stability of prepared wood samples were conducted, as well as crystallinity and microscopic morphologies using Fourier transform infrared spectroscopy, thermogravimetric, plus X-ray diffraction and scanning electron microscopy and energy-dispersive X-ray spectroscopy. Results showed that dye uptake and limited oxygen index had a similar increasing tendency with increased water bath temperature and dipping time. Moreover, dye uptake improved upon addition of flame retardant, while limited oxygen index decreased as dye concentration increases. Flame retardant combined with the wood fiber and was in the absence of chemical reaction with the dye used. Dye and flame retardant molecules diffused into the cell cavity, wood vessel and aperture. Furthermore, the fire-retardant properties and crystallinity of wood simultaneously treated with dye and flame retardant were both improved.     

偶氮染料降解氧化产物苯胺的液相色谱/质谱联用法测定

采用液相色谱/质谱联用法测定由Fenton法降解含偶氮染料的印染废水中的痕量苯胺。降解反应溶液中的苯胺通过HLB固相萃取小柱净化、富集后,在XR-ODS II 柱上,以乙腈/5 mmol/L乙酸铵+0.05%甲酸为流动相进行梯度洗脱,采用电喷雾（ESI）电离正离子多反应监测模式（MRM）测定。结果表明,实验采用的固相萃取小柱能有效地去除溶液中的Fe2+和干扰苯胺测定的化合物,苯胺在10.0–1000.0 μg/L范围内具有良好的线性,相关系数0.9993,回收率在93.0%–98.8% 范围,日内相对标准偏差（RSDs）在3.2%–6.9%之间,日间RSDs在4.8%–6.3%之间,最低定量检出限为2.0 μg/L。建立的方法简便、干扰少、特异性强,应用此法测定Fenton反应液中的痕量苯胺取得了满意的结果。     

木糖母液的综合利用

本文介绍了木糖母液制备焦糖色素的工艺,并对各工艺要点进行了详细讨论,指出以木糖母液制备焦 糖色素的工艺为:(1)、以弱碱除杂;(2)焦糖化反应的温度110～115℃,反应时间小于3.5小时。     

Moisture content (MC) and multinuclear magnetic resonance imaging (MRI) study of water absorption effect on wood treated with aminofunctional silane

The aim of this study was to determine susceptibility of aminoethyl aminopropyl trimethoxysilane (AEAPTMOS)-treated wood to absorption of liquid water. Absorbability was analysed by measuring absolute moisture content of wood and by MRI. These analyses were based on the results of previous studies on resistance against decay fungi in case of wood treated with the same chemical compound. In their previous studies the authors found that AEAPTMOS exhibits enhanced hydrophobic properties and thus increased resistance to the action of specific abiotic and biotic factors. The advantageous fungicidal properties of wood treatment systems indicate that AEAPTMOS may be considered as an environmentally friendly solution, being an alternative to conventional biocidal agents. Results indicate that this method may be used in laboratory analyses assessing the relative amount of water uptake through the wood surface.     

固相萃取-液相色谱法测定水果中的氨基甲酸酯与有机磷农药

建立了固相萃取-高效液相色谱同时测定水果中4种氨基甲酸酯与一种有机磷的方法.对提取溶剂、固相萃取柱种类、洗脱剂类型和用量及检测的色谱条件进行筛选和优化.样品经乙腈超声提取,弗罗里硅土固相萃取柱净化,净化后的样品采用液相色谱柱分离,以甲醇:水(体积比70∶ 30)为流动相,紫外检测波长为210nm,流速1.0mL/min...     

Improved sensitive determination method for bromate in bread

An effective clean-up procedure was developed to determine trace levels of bromate in bread by high-performance liquid chromatography with post-column flow reactor detection. Bromate was extracted from bread with deionized pure water. After centrifugation, the supernatant was filtered through a paper filter. The filtrate was filtered through a 0.2 micron nylon filter and chloride ion was removed by an IC-SP M Ag cartridge column or On-Guard Ag cartridge column. The eluate was applied to an Oasis MAX anion exchange cartridge column. The column was washed with 20% acetic acid and water. Bromate was then eluted with 0.5% sodium nitrate solution. The eluate was determined by HPLC with post column flow reactor detection. The method had a quantitation limit of 2 ng/g in bread products. Recoveries of bromate from bread ranged from 68 to 72% at a spiked bromate level of 2-10 ng/g.     

Preconcentration and Trace Determination of Chromium Using Modified Ionic Liquid Cold-Induced Aggregation Dispersive Liquid–Liquid Microextraction: Application to Different Water and Food Samples

An efficient microextraction procedure based on modified ionic liquid cold-induced aggregation dispersive liquid–liquid microextraction (M-IL-CIA-DLLME) was developed for trace determination of chromium in water and food samples by flame atomic absorption spectrometry (FAAS), and it was used for speciation of Cr(III) and Cr(VI) in water samples by using Na₂SO₃ as the reducing agent. A mixture of water-immiscible 1-hexyl-3-methylimidazolium hexafluorophosphate ([Hmim][PF₆]) ionic liquid (IL) (microextraction solvent) and ethanol (disperser solvent) were directly injected into a heated aqueous solution containing bis(2-methoxy benzaldehyde) ethylene diimine as a Schiff’s base ligand (chelating agent), hexafluorophosphate (NaPF₆; as a common ion) and Cr(III). Afterwards, the solution was placed in an ice-water bath and a cloudy solution was formed due to a considerable decrease of IL solubility. After centrifuging, the sedimented phase containing enriched analyte was determined by FAAS. Under the optimum conditions, the calibration graph was linear over the range of 2–50 μg?L^?1 with limit of detection of 0.7 μg?L^?1. The accuracy of the present methodology was tested by recovery experiments and by analyzing a certified reference material. Relative standard deviation (RSD %) was 2.7 % for Cr(III). The proposed method was successfully applied for trace determination of chromium in water and food samples.     

Färbeverfahren zur Unterscheidung von Holzzonen mit unterschiedlichem Absorptionsvermögen,insbesondere bei Fichtenholz (Picea abies Karst.)

A simple regressive staining method for crosscut wood surfaces is described. Phloroglucinol-hydrochloric acid serves as stain; flowing water and a solution of sodium carbonate are used for development and fixation of a picture showing the differences of obsorption. Hydrophobic zones and, contrary to this, zones with a high water content can also be shown. Comparing green spruce wood before and during drying, the formation of a “secondary heart” became visible. The staining method is useful for solving practical questions and for tests with spruce. It is applicable to other wood species if these show similar differences in absorption.     

Investigation of the interrelations between defibration conditions,fiber size and medium-density fiberboard (MDF) properties

Defibration conditions and raw material properties affect wood fiber characteristics, and thereby the properties of fiber-based panels such as high-density fiberboard (HDF), medium-density fiberboard (MDF) and wood fiber insulation board. This study investigates the influence of steaming conditions (time and temperature), grinding disc distance, wood species (pine, beech, birch and poplar), method of refiner discharging (radial and tangential stock outlet) and wood chip size on fiber length and fiber length distribution, and further the influence of fiber size on MDF properties. Fiber lengths were determined applying the recently developed image analysis-based fiber size measuring system FibreCube. This system enables an automated and nearly complete mechanical separation of woolly-felted fiber samples prior to image acquisition, software-supported post-separation of overlapped-lying fibers at the beginning of image analysis, and flow line tracing-based length measurement. It was found that grinding disc distance and wood species are the most influential parameters on fiber length characteristics. Especially the content of undefibrated fiber bundles (shives) was found to strongly correlate with the grinding disc distance. Wood anatomical differences between hardwood and softwood were reflected clearly by the fiber length characteristics. Fiber size was found to be one of the parameters influencing panel properties. However, other fiber characteristics—in particular the chemical nature of the fiber, which is responsible for its wettability with water (thickness swelling) and glue (mechanical properties)—have to be considered as important influencing parameters on panel properties.     

Bending properties of compressed wood impregnated with?phenolic resin through drilled holes

The effect of drilling on the permeability of Japanese cedar and the bending properties of resin treated compressed wood were examined. Compressed wood was manufactured by impregnating aqueous phenolic resin solutions into the heartwood through drilled holes and polymerizing the impregnated resins using a hot press to maintain the deformation. The compressive deformation was carried out at 150°C for 1 h to one-half of the original specimen thickness. A dye solution permeated the entire specimen when the density of drilled holes exceeded approximately 5000?holes/m². When the compressed wood was manufactured under the drilling condition, the resin type was found to greatly affect the bending strength and the failure mode of the specimens in bending test.     

稳定的高浓度K型液体活性染料的制备

本文针对目前粉状染料存在的粉尘污染、无机盐含量高等问题,研究液体的活性染料的制备。以活性嫩黄K-6G为研究对象,通过对商品染料进行提纯降低染料中无机盐的含量,测定液体染料稳定的pH范围,选用合适的缓冲溶液来提高液体染料的稳定性,并选用合适的有机溶剂来提高液体活性染料的浓度。结果表明,液体活性嫩黄K-6G稳定的pH范围为6-7.5,缓冲溶液选用Tris+EDTA-2Na,用量在5%左右,有机溶剂可选用正丁醇、异丙醇、N,N-二甲基甲酰胺,用量在10%时具有较好的效果。     

Ratiometric Oxygen Imaging to Predict Oxygen Diffusivity in Oak Wood During Red Wine Barrel Aging

In this work, we present a high-resolution oxygen imaging approach to study the two-dimensional oxygen distribution inside an oak stave in contact with wine and that applies the series resistance model to explain the dynamic evolution of oak wood oxygen transfer rate (OTR). Oxygen flux throughout the oak stave has been studied by considering the wood as a permeable membrane with moisture content (MC) in a decreasing gradient from the wine-contacting side of the oak stave to the side in contact with atmospheric air in cellar conditions. The presence of different levels of liquid across the thickness of the wet stave modifies the oxygen diffusion flux, as the diffusion coefficient of oxygen in water is four orders of magnitude lower than in air. The stave resembles a multilayered membrane, where wood with an MC over the fiber saturation point represents a distinct layer. To that end, three simultaneous measurements were made, namely the MC profile of the wood within the thickness of the stave at different liquid-wood contact times, the OTR of the stave at those times, and finally the oxygen concentration profile within the thickness of the stave using planar optical sensors, a color camera, and ratiometric image analysis. The results show heat flux and oxygen flux that is analogous to that in a multilayer.     

Application of fluid modeling to determine threshold leak size for liquid foods

In this study, the mechanism by which a package defect converts to a leaker was examined in an effort to develop a relationship between threshold leak size and loss of package sterility. The threshold leak size is the hole size at which the onset of leakage occurs. The threshold pressure is the pressure required to initiate a leak. Leak initiation was studied in terms of the interaction between three components: liquid attributes of liquid food products, defect size, and pressures required to initiate liquid flow. Liquid surface tension, viscosity, and density values were obtained for 16 liquids. The imposed pressures required to initiate flow through microtubes with interior diameters of 0, 2, 5, 7, 10, 20, and 50 microm were measured with the use of 63 test cells filled with safranin red dye, tryptic soy broth, and distilled water with surface tensions of 18.69, 44.09, and 64.67 mN/m, respectively. Significant differences (P<0.05) between threshold pressures observed for safranin red dye, tryptic soy broth, and distilled water were found. Liquids with low surface tensions, such as safranin red dye, required significantly lower threshold imposed pressures than did liquids with high surface tensions, such as distilled water (P<0.05). An equation to quantify the relationship between liquid surface tension, threshold imposed pressure, and defect size was developed. Threshold pressures observed were not significantly different (P>0.05) from those predicted by the equation. Imposed pressures and vacuums generated within packages during random vibration and sweep resonance tests were measured for brick-style aseptic packages (250 ml), metal cans (76.2 by 114.3 mm [425 ml]), 1-qt gable-top packages (946 ml), 0.5-gal gable-top packages (1.89 liters), and 1-gal milk jugs (4.25 liters). Significant differences between packages were found with respect to observed generated pressures during vibration testing (P<0.05). An equation to calculate threshold size on the basis of liquid surface tension and imposed pressure was established.     

Removal of ionic dyes from water by solvent extraction using reverse micelles

Several methods (e.g., UV/H2O2 oxidation, adsorption, flocculation-precipitation) are normally employed to remove dye from water. A new technique based on liquid/liquid extraction using reverse micelles is proposed whereby recovery of solvent and reuse of dye is possible. Experiments were conducted by mixing a known quantity of dye in aqueous phase and solvent-containing surfactants in a simple mixer. The separation of solvent phase, containing encapsulated dye in reverse micelles, from aqueous phase due to gravity results in separation of dye from water. The removal of different ionic dyes (e.g., eosin yellow, methylene blue, malachite green, methyl orange, orange G) from aqueous phase in the presence of different cationic and anionic surfactants [e.g., sodium dodecylbenzene sulfonate, sodium bis(2-ethylhexyl) sulfosuccinate, hexadecyltrimethylammonium bromide, and cetyl pyridinium chloride] in different solvents (e.g., amyl alcohol, benzyl alcohol, methyl benzoate, and isooctane) were studied by conducting experiments. The percentage removal of dye from aqueous phase increases with the decrease in dye concentration or with the increase in surfactants concentration. Furthermore, the percentage COD removal of dye is increased with the increase in surfactant concentration. The nature of solvent has minimal effect on percentage removal of dye. The ratio of solventto aqueous phase volume required for the removal of dye decreases with the increase in surfactant concentration. It is possible to back-extract dye into aqueous phase and recover solvent by using counterionic surfactants. The separation of aqueous phase from the aqueous-phase solvent dispersion is faster for amyl alcohol as compared to benzyl alcohol and methyl benzoate. A theoretical model based on ion-exchange reaction between surfactants and dye is used to analyze the experimental data.     

Beschleunigte Fixierung chromathaltiger Holzschutzmittel durch Heißdampfbehandlung

During the rapid fixation of water-borne wood preservatives a liquid residue occurs, which is commonly known as “condensate”. However, it consists only partly of condensed steam, which precipitates on the wood surface, on cold metals (e.g. bogies), and on the wall of the steaming vessel if this is not heated seperately. In addition, due to the warming of the outer part of the treated wood, liquid is driven out. The liquid residue contains the preservative components in a concentration of approximately 1/10 of the original solution; simultaneously the pH rises. In the liquid residue some sludge formation takes place within about 24 hours if the residue is not used for producing new preservative solutions, which is possible according to present knowledge.     

Determination of trace levels of cobalt ion in different real samples using dispersive liquid–liquid microextraction followed by flame atomic absorption spectrometry

Dispersive liquid–liquid microextraction technique followed by flame atomic absorption spectrometry was used for preconcentration and determination of trace levels of Co(??) in different real samples. Cobalt ion was first complexed by diethyldithiocarbamate (DDTC) followed by the extraction of resulting complex into the extraction solvent by dispersive liquid–liquid microextraction (DLLME). In DLLME, a mixture of 1.5 mL of methanol (as disperser solvent) containing 50 µL of carbon tetrachloride (as extraction solvent) was rapidly injected into the sample solution to extract the hydrophobic complex of Co-DDTC complex. Under the optimum conditions, the calibration curve was linear in the range of 40–300 µg L^?1 of Co(??) with a correlation coefficient of 0.9966. The relative standard deviation based on six replicate analysis of 100 µg L^?1 of Co(??) was 3.6% and the detection limit was 6.6 µg L^?1. The accuracy of the proposed method was evaluated by the analysis of a certified reference material. Also, the proposed method was successfully applied for determination of trace levels of Co(??) in different water, spinach leaves, black and green tea and tomato sauce samples.     

Prüfung der Widerstandsfähigkeit von Furnierplatten gegenüber holzzerstörenden Basidiomyceten

A laboratory test method proposed in 1982 for testing the preventive effects of wood preservatives in plywood against wood destroying basidiomycetes used vermiculite+nutrient liquid+feeding wood as nutrient medium. Different nutrient liquids were tested with optimum results achieved with a buffer-malt-solution. This solution not only gave satisfactory wood decomposition values with brown rot fungi on solid wood, but also on plywood. Apart from the culture flask specified in pr EN 113, one way plastic test vessels proved to be suitable culture containers for this procedure. In a test with plywood manufactured with an adhesive mixed with wood preservative considerable mass losses due to Trametes versicolor were found even with high preservative concentrations. The tests provided good wood decomposition values for plywood from different wood species and combinations for Trametes versicolor CTB 863 A, Lentinus cyathiformis CTB 67-02 B, Stereum spec. BAM 544 and Gloeophyllum trabeum BAM Ebw. 109. For final decisions on the test fungi further tests with plywood and different fungal strains are required.     

Automated analysis of nanomolar concentrations of phosphate in natural waters with liquid waveguide

Concentrations of phosphate in natural waters are often below the detection limits of conventional nutrient autoanalyzers, by either gas-segmented continuous-flow analysis orflow injection analysis. A liquid waveguide capillary flow cell has been used to extend the sensitivity of a conventional autoanalyzer for the automated analysis of nanomolar concentrations of phosphate in natural waters. Total reflection of light can be achieved within the liquid core of the flow cell because the refractive index of a cell wall coated with Teflon 1600 is lower than that of water. This property allows the manufacturers to construct long liquid waveguide capillary flow cells in a helical, rather than a linear shape, with compact dimensions. A small sample volume is required because the internal volume of a 2-m long capillary flow cell is only approximately 0.5 cm3. Adaptation of this long flow cell to autoanalyzers significantly enhances the sensitivity of automated colorimetric analysis of phosphate with a molybdenum blue method, allowing for the accurate and precise determination of nanomolar concentrations of phosphate in natural waters. The advantages of this technique are a low detection limit (0.5 nM), a small sample volume (2 mL), high precision (2% at 10 nM levels), and automation for the rapid analysis of a large number of samples.     

离子色谱法测定食品中的无机铵

建立一种离子色谱法(IC)快速测定食品中铵根离子含量。样品用水浸泡并混匀,加入乙酸酸化,乙腈沉降蛋白,并一起通过冷冻离心去除脂肪,取适量上清液挥干后用1.0mL水复溶,过膜后备用。以H2SO4溶液梯度淋洗,淋洗液流速为1.0mL/min,采用DIONEX IonPac CS12A色谱柱分离,带抑制器的电导检测器检测,外标法定量。结果表明:NH4+的线性范围为0.1～20.0mg/L,线性相关系数R2大于0.995,检测限(LOD)为0.05mg/kg,定量限(LOQ)为0.1mg/kg,加标回收率为74%～110%,其相对标准偏差(RSD)小于5%。该方法简便,灵敏,准确,适用于多种食品中微量铵根离子的检测。