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1.
Specimens of Scots pine sapwood (Pinus sylvestris) and beech (Fagus sylvatica) were treated with a sodium water glass solution and 1,3-dimethylol-4,5-dihydroxyethylene urea (DMDHEU). The pH-values of water glass treated specimens were between 9.7 and 12.0. Those of DMDHEU treated specimens were 3.8 (Scots pine) and 4.2 (beech). The resistance observed in an eight weeks laboratory test against the blue stain fungus Aureobasidium pullulans showed that treatments with water glass and DMDHEU reduced but not prevented the fungal growth. Wood specimens treated with water glass showed the lowest colonisation of blue stain. Both treatments inhibited fungal penetration through the ray cells. HPLC analysis showed that the amount of simple sugars was reduced due to water glass treatment. The amount of simple sugars in DMDHEU treated wood depended on the wood species. The amount of available sugar monomers did not indicate an influence of the colonisation of the sample surface.  相似文献   

2.
The aim of this paper is to explain how colour fastness results are improved as a result of increasing the degree of fixation of reactive dyes on wool, polyamide and wool–polyamide blend fabrics. Wool–polyamide blend fabrics were printed with two different types of reactive dyes, e.g. monochlorotriazine and vinylsulphone. Trichloroacetic acid (TCAA) was added to the printing paste for controlling the pH level during the fixation process to get a maximum colour yield and a maximum dye fixation on the two components of the blend, e.g. wool and polyamide. In order to accelerate the reaction rate, a quaternising agent, e.g. triethylamine (TEA) was also added to the printing paste. The factors that may affect the efficiency of printing method, e.g. the concentration of TCAA, urea, wetting agent, TEA, steaming time and temperature were studied in detail.  相似文献   

3.
The development of twist in Norway spruce boards (Picea abies Karst.) during normal temperature kiln drying was researched. Tangentially oriented boards were sawn from diametrical radial planks, from which the basic wood properties, i.e. linear shrinkage and grain angle, were determined. The unrestrained boards were kiln dried using a selected drying schedule. During the controlled drying process the moisture content (MC) and twist of the boards were measured. Twist was generally induced by the shrinkage of wood below the fibre saturation point, and increased in proportional to the decrease in MC. The earlier appearance of twist, with regard to MC and drying time, was confirmed in the case of boards sawn from the central part of logs. The final twist amounted to between 10 and 20°/m in the case of boards close to the pith, and decreased to less than 4°/m in the case of boards sawn at a radius of 70 mm from the centre of the logs. Ring curvature had the highest impact on the final twist of the dried boards, followed by grain angle and tangential shrinkage.  相似文献   

4.
The survival of two bacteria, Escherichia coli and Listeria monocytogenes was observed on pine heartwood and glass surfaces by using a simple test method. The development of the number of bacterial cells was evaluated by titration after vortexing the samples in BHI broth and culturing the resulting broth on agar plates. The bacterial count decreased clearly faster on pine heartwood than on glass surfaces. This result was confirmed by studying the wooden samples also one day after to exclude possible adherence of the bacterial cells on the porous surface. This study confirms the results of several other studies that suggest wood to have antibacterial properties.  相似文献   

5.
The term technology is frequently used in every-day communication and in the specific areas of producing goods and providing services. Technology comprises the science of knowledge and usage of tools and techniques or its systems, methods, organization and material products thereof. The meaning of the word technology itself as well as the specific meaning of the term wood technology has changed over the past centuries of industrialized production systems. The current paper analyses the development of wood technology over a period of about 300 years. Based on various COST Actions and the European Forest-sector Technology Platform current topics of wood technology are addressed and a future outlook is given.  相似文献   

6.
A test apparatus based on electrical conduction principle was designed and manufactured to overcome some difficulties and deficiencies in vertical wicking measurements of fabrics, which is one of the test methods used to determine liquid moisture transmission performance of fabrics. In order to test effectiveness of the apparatus, capillary time with regard to height was measured for woven shirting fabrics, which have different raw material, weave type and weft density. It was found that twill weave type and fabric looseness improved the wickability of fabrics. It was also revealed that raw material was an important factor for vertical wicking. The wicking rate of fabrics obtained from the new test apparatus correlated well with DIN 53924. Consequently, the test apparatus clearly demonstrated differences between the fabrics used in the study, and can be used to determine vertical wicking behaviour of fabrics.  相似文献   

7.
This review examines the application, limitations, and potential alternatives to the Hagberg–Perten falling number (FN) method used in the global wheat industry for detecting the risk of poor end-product quality mainly due to starch degradation by the enzyme α-amylase. By viscometry, the FN test indirectly detects the presence of α-amylase, the primary enzyme that digests starch. Elevated α-amylase results in low FN and damages wheat product quality resulting in cakes that fall, and sticky bread and noodles. Low FN can occur from preharvest sprouting (PHS) and late maturity α-amylase (LMA). Moist or rainy conditions before harvest cause PHS on the mother plant. Continuously cool or fluctuating temperatures during the grain filling stage cause LMA. Due to the expression of additional hydrolytic enzymes, PHS has a stronger negative impact than LMA. Wheat grain with low FN/high α-amylase results in serious losses for farmers, traders, millers, and bakers worldwide. Although blending of low FN grain with sound wheat may be used as a means of moving affected grain through the marketplace, care must be taken to avoid grain lots from falling below contract-specified FN. A large amount of sound wheat can be ruined if mixed with a small amount of sprouted wheat. The FN method is widely employed to detect α-amylase after harvest. However, it has several limitations, including sampling variability, high cost, labor intensiveness, the destructive nature of the test, and an inability to differentiate between LMA and PHS. Faster, cheaper, and more accurate alternatives could improve breeding for resistance to PHS and LMA and could preserve the value of wheat grain by avoiding inadvertent mixing of high- and low-FN grain by enabling testing at more stages of the value stream including at harvest, delivery, transport, storage, and milling. Alternatives to the FN method explored here include the Rapid Visco Analyzer, enzyme assays, immunoassays, near-infrared spectroscopy, and hyperspectral imaging.  相似文献   

8.
The scope of this work is to discuss the challenges and demonstrate the potential of microwave testing for applications in the wood processing industry. Microwave technology benefits from the anisotropic dielectric properties of wood to simultaneously identify grain angle, density, and moisture content of wood. Therefore, the theory of free space transmission measurement is thoroughly discussed with emphasis on the characteristics of (and how to deal with) reflections occurring in real measurements. A more sophisticated calculation method for the derivation of the desired physical wood properties is presented. The advantages of a modern laboratory style setup are shown and its possible transition in an industrial-style application is discussed. Moist (moisture content 7.6–14%) and oven-dry spruce samples are tested. The detection of grain angle for moist and oven-dry wood yields an RMSE (root-mean-squared-error) of 0.14° and 0.4°, respectively. Moisture content is evaluated with density- and thickness-independent methods. Adapted regression models are proposed yielding an RMSE for moisture content of 0.45% for a single frequency measurement. The promising advantages of wood moisture estimation with frequency sweeps instead of fixed frequency signals are discussed and demonstrated for all samples (RMSE 0.39%). The dielectric constant of moist and oven dry spruce in the range from 8 to 12 GHz is evaluated in respect to density, moisture content and temperature. The respective constants ε′, ε′′, and tan(δ) are formulated in a general form via a non-linear regression and compared to existing data in literature.  相似文献   

9.
Consumer demand for pomegranate juice has considerably grown, during the last years, for its potential health benefits. Since it is an expensive functional food, cheaper fruit juices addition (i.e., grape and apple juices) or its simple dilution, or polyphenols subtraction are deceptively used.  相似文献   

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11.
Loss of area freedom from invasive alien species can have serious food security implications and place huge responsibility on incursion response managers. They make critical decisions despite profound uncertainty surrounding invasion ecology, surveillance and control technology effectiveness and human behaviour. We propose a spatially-explicit model that can aid response managers in devising and testing management strategies in a virtual world where the costs of failure are negligible. We apply the model in a group-based decision setting in which participants practise responding to fictional disease incursions in a pome fruit production area in Australia. Using the model, the response management group was able to develop mutually satisfactory rules of thumb for the use of quarantine and destruction zones and for when to withdraw resources from eradication efforts.  相似文献   

12.
The seven Anglerfish species, which belong to the genus Lophius, have a different value on the market, worldwide. If whole fishes can be identified by their morphological characteristics, they become indistinguishable when prepared or processed. In this study, a rapid method based on polymerase chain reaction–restriction fragment length polymorphism (PCR–RFLP) was developed for the authentication of the seven Lophius species, using a cytochrome b gene fragment of 566 bp. After a genus-specific PCR, a fast digestion with the restriction enzyme BfaI, followed by agarose gel electrophoresis, allowed a clear species identification by producing specific restriction patterns. The total time required was as low as 6 h, DNA extraction included. The method was then used to analyse 48 commercial samples, whose phylogenetic analysis confirmed the PCR–RFLP response at 100 %. Results showed that mislabelling occurs on the market regardless the kind of processing.  相似文献   

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15.
Petrifilm(?) PEC was compared to Australian Standard (AS) methods for the enumeration of coliforms and Escherichia coli on 50 naturally contaminated beef samples from three meat works. The standard methods consist of a 3-tube most probable number test or a direct plate count on tryptone bile agar for E. coli, and violet red bile agar and the most probable number test for conliorms (AS 1766.2.12.1984 and AS 1766.2.3.1992). No significant difference was found between the methods, except that the count of E. coli on the direct plate method with a resuscitation step was significantly higher than the count on Petrifilm(?), most probable number or direct plate count without resuscitation.  相似文献   

16.
17.
A novel, simple, easy and cheap sample treatment strategy based on salting-out assisted liquid-liquid extraction for ochratoxin A (OTA) ultra-trace analysis in beer samples using ultra-high-performance liquid chromatography-tandem mass spectrometry determination was developed. The factors involved in the efficiency of pre-treatment were studied employing factorial design in the screening phase and the optimal conditions of the significant variables on the analytical response were evaluated using a central composite face-centred design. Consequently, the amount of salt ((NH4)2SO4), together with the volumes of sample, hydrophilic (acetone) and nonpolar (toluene) solvents, and times of vortexing and centrifugation were optimised. Under optimised conditions, the limits of detection and quantification were 0.02 µg l?1 and 0.08 µg l?1 respectively. OTA extraction recovery by SALLE was approximately 90% (0.2 µg l?1). Furthermore, the methodology was in agreement with EU Directive requirements and was successfully applied for analysis of beer samples.  相似文献   

18.
The objective of this work is to optimize the arrangement of the fibers to reduce damage to the fiber matrix interface of a composite material. The results obtained by the genetic algorithm based on the volume fraction of reinforcement show a good agreement between numerical simulation and the actual behavior of both materials T300/914 and PEEK/APC2, however, it would be interesting to see the effect of thermal stress on the optimization of the arrangement by the molecular dynamics method.  相似文献   

19.
The potential of the anti-homogalacturonan(HG) antibodies JIM5, JIM7, LM7, LM18, LM19, LM20 and PAM1 for investigating the effect of processing on pectin in fruit and vegetable tissues was screened in this study. In this respect, the specificity of the antibodies towards pectin and methoxylated polygalacturonic acid with defined degrees and patterns of methylesterification was elaborated, leading to a substantial extension of the information already available in literature. Based on the obtained specificities, the distribution of pectin methylesterification in carrot and broccoli tissue was mapped. It was established that pectin with a low degree of esterification (DE) and a more blockwise distribution of the methylesters is, both in carrot and in broccoli, preferentially located at the tricellular junctions between adjacent cells. This cell wall region, however, is also likely to contain other structural pectic domains. The inner face of the cell wall adjacent to the plasma membrane seems to contain pectin with a medium DE. To evaluate the potential of the anti-HG antibodies to detect changes in degree and pattern of methylesterification caused by processing, carrot and broccoli were subjected to a thermal treatment aimed to stimulate the endogenous pectinmethylesterase (PME) activity. It was revealed that process-induced de-esterification by endogenous PME mainly tends to take place at discrete regions of the inner face of the cell wall adjacent to the plasma membrane for carrot and in tricellular junctions and the middle lamella for broccoli.  相似文献   

20.
Listeria and Campylobacter genera include some of the most widely spread human pathogens across Europe and represent a serious health threat, especially to children, immunocompromised people and pregnant women. Both genera are frequently isolated from farm animals and food; therefore, their rapid detection is important for food safety and to prevent disease outbreaks. A rapid detection approach based on the combination of ligation detection reaction and universal array (LDR–UA) was developed to reveal the presence of Listeria and Campylobacter pathogenic species and to identify the Division (I, II and III) of L. monocytogenes isolates. The approach was tested first on reference strains then on field isolates. The LDR–UA approach showed high sensitivity and high specificity in reliably discriminate target sequences differing in as little as one base pair, thus facilitating the discrimination of closely related strains.  相似文献   

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