Thermal modification of OSB-strands by a one-step heat pre-treatment – Influence of temperature on weight loss, hygroscopicity and improved fungal resistance

Thermal modification of wood leads to improved resistance against fungal decay and decreased moisture uptake. Polyoses contribute most to the sorption behaviour of wood and act as main nutrition source for fungi. Thus, especially the conversion of polyoses has major impact on the degree of improvement. Thermal decomposition of wood is accompanied by weight loss. In this work the influence of temperature on weight loss, resulting equilibrium moisture content (EMC) and fungal resistance of OSB-strands is shown. It was found that EMC reaches a constant level, indicating completed reduction of free accessible hydroxyl groups. The levelling was ascertained to be irrespective of the temperature and duration of the pre-treatment. An improved fungal resistance according to durability class 3 and better was found for samples pre-treated above 200 °C. The presented correlation between reduced EMC and improved fungal resistance provides a tool for efficient determination of the durability of thermally modified wood.     

毛织物同步法热转移印花工艺研究

文章提出了一种新的毛织物热转移印花方法--同步法,介绍了助色剂的选择标准及同步法的工艺流程,对同步法工艺专用助色剂的种类、浓度及其聚集体对助色效果的影响进行了研究.采用皂洗牢度、清晰度表征热转移印花布样,分析了助色剂的种类、浓度及其聚集体对助色效果的影响.结果表明其色牢度和清晰度均能达到国家标准,通过后处理提高了热转移印花布样的颜色稳定性和深度,说明同步法与后处理结合,能够良好地实现毛织物的热转移印花.     

Mechanical and physical properties of cement-bonded OSB

The objective of this paper was to evaluate the mechanical and physical properties of oriented strand board (OSB) using cement as binder. It was found that an increase of cement-wood ratio resulted in an increase of all, but MOR values. A lower cement-wood ratio than for particleboards is required in order to manufacture acceptable OSB and this may be due to the strands geometry.     

Mechanical and physical properties of cement-bonded OSB

The objective of this paper was to evaluate the mechanical and physical properties of oriented strand board (OSB) using cement as binder. It was found that an increase of cement-wood ratio resulted in an increase of all, but MOR values. A lower cement-wood ratio than for particleboards is required in order to manufacture acceptable OSB and this may be due to the strands geometry.     

Effect of ultrasound pre-treatment on the kinetics and thermodynamic properties of guava slices drying process

The present work aims to evaluate the influence of sonication pre-treatment on the drying kinetics of guava circular slices in electric oven. Circular guava slices with 6.0 mm thickness were pre-treated with ultrasound for 0 min, 10 min, and 20 min, respectively. Drying kinetics experiments were performed at the temperatures of 50, 70, and 90 °C using an electric oven at 1200 W. Drying kinetics experimental data were fitted using empirical models and a diffusive model with third type boundary conditions. Process activation energy and thermodynamic properties were also determined. Drying of pre-treated samples revealed higher drying rates and less process time. Both Page and the diffusion models were adequate to describe the drying phenomena presenting coefficients of determination higher than 0.99 and low chi-squared values. Results also revealed that sonication times increased moisture transport rates with uniform distribution along with the interior of the slices during drying. The activation energy and enthalpy presented negative values and a positive correlation with the sonication time, while entropy and Gibb's free energy presented positive values and a negative correlation to the sonication time.     

The effects of a two stage heat treatment process on the properties of particleboard

Steam pre-treatment can effectively improve the dimensional stability of panel products such as particleboard and fiberboard. At temperatures above 200–210 °C steam pre-treatment might result in a significant reduction of the bond strength of the panel product. The results of an effective two stage heat pre-treatment process, in which treatment temperatures below 200 °C are used, are given in this paper. The variations in process conditions which affect the particleboard properties are described in detail. A two- stage heat pre-treatment with temperatures below 200 °C appears to improve the dimensional stability of panel products. The process conditions used have an effect on thickness swelling and internal bond properties of the particleboard prepared, especially during the first process stage (hydrothermolysis). The best results were obtained with wood particles which were only thermolysed (without curing).     

Improvement properties of nylon fabric by corona pre-treatment and nano coating

This article tries to represent a supplemental method based on surface modification in order to optimizing the per cent of nano cohesion to give the better performances, such as antibacterial resistance and UV-blocking characteristic (especially in nano-ZnO), which nanoparticles carry inherently. Corona treatment was used to modify the surface of Nylon 6 fabrics in Sixdifferent conditions (related to power and passages). Treated fabrics were dyed with acidic dye and imbued with nano-ZnO simultaneously and antibacterial property, dye absorption and UV-blocking characteristic of samples were investigated. Scanning electron microscopy (SEM) was used to observe a porous Nylon fibre consisting of nano-ZnO. By increasing the power and number of passages of the corona atmosphere in which samples were contacted with, the water absorption increased. The result demonstrated that by increasing power and passages of corona treatment, dye absorption decrease likely due to the increase of the nano-ZnO cohesion. UV blocking increased in relation with increasing power and passages of corona treating. Results from antibacterial property on samples showed that by increasing the power and passages of corona treatment, the fabrics became more resistance to Staphylococcus aureus and Escherichia coli bacteria.     

Composting cattle dung wastes by using a hyperthermophilic pre-treatment process: characterization by physicochemical and molecular biological analysis

To solve malodorous odor problems by ammonia emission in composting of cattle dung wastes, we developed an alternative composting method consisting of a hyperthrmophilic pre-treatment reactor (HTPRT) (first step) combined with a general windrow post-treatment system (WPOT) (second step). In this study, physicochemical and microbiological differences in compost materials during the HTPRT-WPOT process and a simple windrow composing process (SWC) were investigated. The HTPRT-WPOT process removed excess ammonia in the compost materials by physical ammonia stripping, and controlled the malodorous ammonia emission. The organic matter evolution index showed that the HTPRT-WPOT process also contributed to accelerate formation of humic acids in composting. Quantitative real-time PCR analyses using Bacterial-, Archaeal- and fungal-protozoan-specific primer sets showed that small subunit ribosomal RNA (SSU rRNA) gene copy numbers differed much between composting materials of these two processes. Particularly, the SSU rRNA gene copy of eukaryotic microbes (fungi-protozoa) in the HTPRT-WPOT process was much higher than in the SWC process. From these results, we conclude that the HTPRT-WPOT process has great advantages for the control of malodorous odor problems caused by ammonia emission, and for high rate of composting evaluated by the humification rate and microbial characterization of the composting materials.     

A comparison of low-intensity ultrasound and oscillating rheology to assess the renneting properties of casein solutions after UHT heat pre-treatment

Ultrasonic and oscillating rheological methods were applied to investigate the effects of heat pre-treatment at Ultra-High-Temperatures on the rennet gel formation of a whey-protein-free casein solution. By comparison, the ultrasonic velocity was found to be sensitive to measure the enzymatic hydrolysis by rennet and the following aggregation process, but not as sensitive to detect the formation of a casein gel. In contrast, the oscillating rheological method was not sensitive enough to detect the enzymatic hydrolysis, but more suitable to characterize the formed gel network. A linear correlation was found between the coagulation times determined by these two methods.     

一体化聚酯瓶生产工艺探讨

<正> 一步法PET瓶生产的整个过程是连续进行的,能在任何阶段进行参数的调整,确保瓶坯及瓶子的质量稳定。     

Fire performances of foam core particleboards continuously produced in a one-step process

For further progress of novel foam core particleboards, their fire performance was examined with cone calorimetry tests (ASTM E 1354-11a). Specimens with varying surface layer thicknesses, foam densities (polystyrene foam), and processing temperatures were tested. Using the initially recommended cone irradiance of 35 kW/m², different flammability parameters were measured. In comparison to particleboards, the foam core panels generally had much higher heat release rates, somewhat higher heat of combustion and much higher smoke production due to the EPS-foam component of tested panels. The time to ignition and total heat release did not vary significantly among the samples, although certain trends could be explained. The effects of variations in specimen foam densities and processing temperatures on the flammability parameters were not very significant. However, the flammability properties improved towards that of the reference particleboard as the surface layer thickness increased from 3 to 5 mm.     

棉织物低温近中性一浴一步法练漂

为实现基于生物酶的棉织物短流程前处理,构建出过硼酸钠/四乙酰乙二胺(SPB/TAED)低温活化体系,并将果胶酶与纤维素酶溶入该体系对棉织物进行同浴练漂。通过变量控制法分析了酶的种类与质量浓度、SPB与TAED的质量浓度、时间与温度对织物白度与毛效的影响,得到优化的一浴一步工艺:果胶酶、纤维素酶、SPB、TAED、渗透剂质量浓度分别为1、2、15、25、1 g/L,时间为60 min,温度为60 ℃。将此低温工艺与传统的高温(95 ℃)碱性(pH 值12~13)工艺进行对比,结果表明:前者节能优势明显;2种工艺条件下的练漂棉织物具有相当的白度、吸湿性、可染性,但低温练漂织物的强力明显较高,其表面更光滑且杂质较少。     

Evidence on the role of protein biosynthesis in the induction of heat tolerance of Lactobacillus rhamnosus GG by pressure pre-treatment

It was the aim of this work to evaluate, whether and to which extent heat resistance of Lactobacillus rhamnosus GG is affected by mild pressure treatments prior to exposure to lethal temperatures, such as during spray-drying. It was observed that cells pressure pre-treated at 100 MPa at 37 degrees C for 10 min showed higher survival than untreated cells when exposed to heat challenge at 60 degrees C. To gain more insights on the cellular mode of action of pressure induced heat tolerance, flow cytometric analysis was applied in combination with functional dye LIVE/DEAD BacLight bacterial viability kit. Dot plot analysis showed that a lower degree of membrane damage was observed at pressure pre-treated cells upon heat treatment at 60 degrees C for 3 min. Evaluation of heat inactivation kinetics of cells pressure treated in the presence of chloramphenicol, a protein synthesis inhibitor, pointed out the potential contribution of pressure-induced protein biosynthesis in the enhancement of bacterial heat tolerance.     

Effect of pulsed electric field pre-treatment on the debittering process of cherry kernels

Cherry kernels occur in significant amounts as waste material during the processing of fruits. However, their subsequent use is limited due to the presence of cyanogenic glycosides, which are potentially dangerous to human health. In this study, the application of pulsed electric fields (PEF) was investigated as pre-treatment to improve the debittering process and to facilitate the degradation of cyanide precursors, naturally present in cherry kernels. Diverse PEF treatments were carried out at constant electric field strength of E = 2.2 kV/cm and specific energy input was varied between 10 and 50 kJ/kg, varying the number of pulses. Two different debittering procedures were performed with a common incubation time 0–20 h at 40 °C: a) incubation of whole kernels in deionized water; b) incubation of whole kernels without water stored in air at 80% relative humidity. HPLC analysis was used to examine the kinetics of the amygdalin and HCN contents. In both debittering methods, the PEF-treated samples with the highest intensity (2.2 kV/cm, 50 kJ/kg) showed higher and faster detoxification efficiency for the investigated compounds as compared to the untreated sample. In particular, the PEF treated samples incubated with water showed a reduction in the amygdalin and HCN contents of up to 86% (up to 72% of the raw material content.). Moreover, the PEF pre-treatment led to comparable efficiency in amygdalin reduction in both debittering processes: 86% reduction for the incubation with water and 81% for the incubation without water. Consequently, the combined application of PEF and the debittering process including incubation without water has remarkable potential as an industrial application due to its inherent reduced water consumption, and therefore, diminished wastewater management issues. A further advantage of this process is the minimizing of sugar loss typically occurring during the debittering through soaking.     

Optimising separation process of protein and polysaccharide from spent brewer’s yeast by ultrafiltration

The aim of this study was to optimise the ultrafiltration process for the separation of polysaccharide and protein from spent brewer’s yeast. Influence of concentration (1.5–4.5%), pH (4.0–8.0) and operating pressure (10–20 psi) on the yield of protein and polysaccharide was assessed using response surface methodology. The optimum separation conditions were found to be concentration 2.7%, pH 5.0 and operation pressure 14.0 psi. Under these conditions, the experimental yields of protein and polysaccharide were 95.03% and 94.65%, respectively, which were agreed closely to the predicted value. The polysaccharide was composed of glucose, sucrose and trehalose in a ratio of 1.12:0.83:2.36. The results indicated that ultrafiltration technology could be an effective and advisable technique for the separation of protein and polysaccharide.     

热处理对鲜切牛蒡贮藏品质的影响

目的采用星点设计-响应面法研究了热处理对鲜切牛蒡贮藏品质的影响。方法对鲜切牛蒡进行不同时间和不同温度的热处理,处理后的牛蒡切片置于23℃±2℃条件下5 d(模拟货架期),对货架结束后的牛蒡色泽L*值、失重率和维生素C(VC)含量进行测定。采用响应面法建立了牛蒡色泽L*值、失重率和VC含量的二次多项数学模型,并验证了模型的有效性。结果热处理鲜切牛蒡的最佳处理温度为46.5℃,处理时间28.8min,在此条件下,牛蒡色泽L*值、失重率和VC含量理论值分别为66.07、0.78%和6.16 mg/100 g。实际测得L*值66.13±1.7,失重率(0.79±0.03)%,VC含量(6.12±0.12)mg/100 g,与预测值基本一致,表明所建模型具有较好的预测性能,可用于指导生产实践。结论热处理可有效降低鲜切牛蒡贮藏品质的下降。     

亚麻纱线煮漂一浴法前处理工艺

研究了亚麻纱线煮漂一浴法前处理工艺.探讨了温度、时间、双氧水用量、烧碱用量、精练剂用量和尿素用量对亚麻纱线煮漂一浴法效果的影响.得出了较优工艺:双氧水12g/L、烧碱10 g/L、尿素6g/L、精练剂2 g/L、110℃、60 min,此时漂白效果较佳.