Improving characteristics of melamine–urea–formaldehyde resin by addition of blocked polyurethane prepolymer

In this paper, the effect of blocked polyurethane prepolymer (BPUP) with four R values (the ratio of –NCO to –OH) and different blending proportions on the characteristics of melamine–urea–formaldehyde (MUF) resin were first investigated. The properties of the modified adhesive systems were examined by dynamic wettability and shear strength. The results indicated that the bonding performance and the wettability of high R value blending modification were superior to that of low R value case. In addition, the optimal bonding performance came from the MUF resin modified by 15% BPUP (R = 5) addition. Besides, the K value on wood substrates with different moisture contents (MC) was calculated by wetting model to interpret the wetting kinetics. The polymer blending adhesive has a potential capacity for making wood-based panels from high-moisture raw materials.     

Permeability anisotropy of flax nonwoven mats in vacuum‐assisted resin transfer molding

The resin flow characteristics of natural fiber mats must be taken into consideration in the design and optimization of liquid composite molding processes. This paper studied two common types of nonwoven mat structures produced by the parallel‐laying process and the cross‐laying process. The flax fiber orientation distribution characteristics of these mats were determined by using a fast Fourier transform (FFT) image analysis algorithm. Flax fiber mats produced by the parallel‐laying method had a prominent principal direction of fiber orientation, while mats produced by the cross‐laying method had a nearly random fiber orientation. The parallel‐laid mats showed a higher overall compressibility than the cross‐laid mats because of the tendency of nesting between layers of parallel fibers, leading to a lower porosity under the same vacuum level and thus a lower overall permeability. The cross‐laid nonwoven mats demonstrated nearly isotropic in‐plane permeability, while the parallel‐laid mats showed a much higher permeability in the principal fiber direction than in the orthogonal direction.     

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.     

On the performance of a melamine–urea–formaldehyde resin for decorative paper coatings

The decorative laminates industry is a highly competitive industrial sector. To be profitable, manufacturers of impregnated papers for surface laminated MDF and particleboards need to significantly reduce their production costs. Melamine formaldehyde resin (MF) formulations are commonly used for impregnation and coating of such papers, melamine being an important, but costly raw material used in high quantities. While MF is substituted by cheaper urea formaldehyde resins (UF) in the core impregnation, for paper surface films pure MF is used. Therefore, a further reduction in cost could be achieved if a portion of the melamine in the surface film was replaced by urea. In the present contribution, recent results of technological tests on paper laminates using a novel melamine–urea–formaldehyde resin (MUF) formulation are reported and their performance is compared to traditional surfaces made from MF.     

Hydroxymethyl furfural-modified urea–formaldehyde resin: synthesis and properties

Considering the importance of urea–formaldehyde (UF) resins in the wood industry, this work reports on a new bio-based modification of UF resins. The use of 5-hydroxymethyl furfural (HMF) is motivated by the current concerns about the effects of formaldehyde on human health. UF and urea–HMF–formaldehyde (UHF) resins were synthesized by an alkaline-acid method and characterized by FTIR, thermogravimetric analysis, and differential scanning calorimetry. The UHF, as a newly modified polymeric resin, was thermally characterized, and it was found that its thermo-stability and char yield was improved. In order to investigate the performance of the UHF, the preparation of particleboards with the UHF as adhesive, as well as its film formation ability have been studied. The UHF films formed on wood panels were uniform without any crack. Film formation ability of the UHF resin was improved due to the presence of more hydroxyl groups as well as furan rings of the HMF moieties resulting in more activated groups to be bonded by wood. Furthermore, formaldehyde release of the particleboards bonded by UHF was significantly lower than that of which bonded by the UF resin. Lab particleboards using the UHF resins showed higher modulus of rupture, modulus of elasticity, and internal bond compared to boards with UF resins, as well as lower water absorption and thickness swelling. Based on these results UHF resin can be considered as a possible candidate as adhesive for wood and wood based panels.     

Potential of shortening pressing time or reducing pressing temperature for plywood resinated with PF resin modified using alcohols and esters

The study was an analysis of the potential to shorten pressing time or reduce pressing temperature for plywood resinated with alcohol- and ester-modified PF resin. Birch and pine plywoods were produced using such modified resin at a temperature range of 135 to 115?°C, at a constant pressing time (4 min) and at pressing times ranging from 240 to 150 s at a constant pressing temperature (135?°C). Tests showed that the application of PF resin modified with polyols and esters makes it possible, under standard pressing conditions, i.e. 135?°C and pressing time of 4 min, to produce plywood with improved properties in comparison to respective control plywoods. Moreover, it was shown that the used modifiers enhance resin reactivity, facilitating an adequate course of resin curing, resulting in the manufacture of plywoods with good properties even at a pressing temperature reduced by 20?°C or pressing time shortened to 150 s.     

Influence of clothing design of characteristics of wool fabric北大核心

Influence of clothing design, fabric cutting and sewing of characteristics of wool fabric was studied in this paper by research the characteristics of wool fibers and fabrics. The studies showed that different temperament and spirit can be shown by different specifications of the fabric with different visual features and appearance characteristics which can affect the design of clothing styles, wave shapes, pattern, etc characteristics of appearance, and choices of suitable clothing technological parameters of comfort, cutting and sewing. It can be drawn conclusion that the characteristics of wool fibers, weaving technology, patterns, color collocation, and clothing technological parameters of comfort, cutting and sewing, etc should be considered to develop the wool fabric with excellent elegant and functionality.     

The Release of Guidance of Accelerating the Development of Renewable Resources Industry

正On January 25~(th),2017,the Ministry of Industry and Information Technology,the Commerce Department and the Ministry of Science and Technology jointly released Guidance of Accelerating the Development of Renewable Resources Industry(hereafter referred to as guidance),aiming at accelerating renewable resources     

The Future of Development of China''''s Printing Industry

The tendency in general Digitizing,Networking,diversification and quickness. Digitizing,networking-Digital and network technology will penetrate the in- dustry even far and wide; Diversification-The color and type of printing products will be developed; Quickness-Quick printing at re- quest and streamlined delivery is a new goal of the printers.     

Conservation of Leaves of a Medicinal Plant of Western Algeria （Pistacia atlantica）

In our context, and in the goal to valorize the Pistacia atlantica species Desfthat grows spontaneously in Algeria occidental except the coastline, and that is used by the nomadic populations in their daily consumptions, we are thinking about drying its leaves. Here, the biochemical analysis of dried leaves ofPistacia atlantica is determined, the sorption is other ms are of great importance in the food industry, especially in the drying; the sorption isotherms of pistachio leaves were measured by the gravimetric method at three temperatures 40, 50 and 60 ℃. The equilibrium was achieved after eight days for desorption and seven days for adsorption with water activity ranging from 5% to 90%. Only the GAB and Peleg models were found to be the most suitable for describing the sorption curves. The isosteric heat of sorption of Pistacia atlantica leaves decreases with an increase in moisture content and was found to be an exponential function of moisture content for adsorption and desorption. The pistachio leaves could be considered as a rich natural source of valuable nutriments （carbohydrates, proteins and lipids）; lipid fraction is equal to 2.25%; proteins are the second macronutriment that predominates in these sheets： 4.35%; accordingly carbohydrates content was about 25.77%.     

Effect of addition of CO₂ to raw milk on quality of UHT-treated milk

The objective of this study was to evaluate the effect of addition of CO(2) to raw milk on UHT milk quality during storage. Control milk (without CO(2) addition) and treated milk (with CO(2) addition up to pH 6.2) were stored in bulk tanks at 4°C for 6d. After storage, both samples were UHT processed using indirect heating (140°C for 5s). Samples were aseptically packed in low-density polyethylene pouches and stored in the dark at room temperature. Raw milk was evaluated upon receipt for physicochemical composition, proteolysis, lipolysis, standard plate count, psychrotrophic bacteria, and Pseudomonas spp. counts, and after 6d of storage for proteolysis, lipolysis, and microbial counts. After processing, UHT milk samples were evaluated for physicochemical composition, proteolysis, and lipolysis. Samples were evaluated for proteolysis and lipolysis twice a month until 120d. Peptides from pH 4.6-soluble N filtrates were performed by reversed-phase HPLC after 1 and 120d of storage. A split-plot design was used and the complete experiment was carried out in triplicate. The results were evaluated by ANOVA and Tukey's test. After 6d of storage, CO(2)-treated raw milk kept its physicochemical and microbiological quality, whereas the untreated milk showed significant quality losses. A significant increase in proteolysis occurred during 120d of storage in both treatments, but the increase occurred 1.4 times faster in untreated UHT milk than in CO(2)-treated UHT milk. In both UHT milks, the proteolysis was a consequence of the action of plasmin and microbial proteases. However, the untreated UHT milk showed higher microbial protease activity than the treated UHT milk. The addition of CO(2) to the raw milk maintained the quality during storage, resulting in UHT milk with less proteolysis and possibly longer shelf life, which is usually limited by age gelation of UHT milk.     

Biological control of Penicillium italicum of Citrus and Botrytis cinerea of Grape by Strain 34–9 of Kloeckera apiculata

The biological control capability of strain 34-9 of Kloeckera apiculata against Penicillium italium (Wehmer), postharvest rot of citrus fruits and Botrytis cinerea, postharvest rot of grape fruits was studied in vitro and in vivo. Strain 34-9 of K. apiculata at 3×10⁸ CFU (colony-forming unit)/ml of washed cells provided complete control of 3×10⁵ spores/ml of P. italium and B. cinerea during storage at 25 °C for 6 d. Antagonist population increased 40, 195 times in citrus fruit wound site and grape fruit wound site at 25 °C for 3 d, respectively, then the population stabilized for the remaining storage period. Cell-free culture filtrate, supernatant fluid and sterilized solution of strain 34-9 of K. apiculata had no antagonist against P. italium of citrus and B. cinerea of grape. These results showed that competition for nutrient, not antibiotic production, played a major role in the biological control capability of strain 34-9 of K. apiculata against P. italium of citrus and B. cinerea of grape.     

Hygienic evaluation of the state of nutrition and noninfectious sickness rate of digestive organs of the Primorskiĭ Kraĭ population

The research of nutrition status of Primorsky Krai population in 1996-1999 showed positive tendency to quantitative improvement of structure of nutrition set. At the same time in connection a nutrition of Primorsky Krai population doesn't correspond to the standard of balanced nutrition. Some decrease of deficiency of basic food products in nutrition and an increase of energy value of food ration are observed. Children group of population is the most susceptible to unbalanced and defective nutrition that is why a pathology of digestive system of noninfectious nature develops intensively among children.     

Competition of Ideas for the Design of a Chair

The competition is open worldwide to architects, and designers as well as students enrolled in Tertiary Design Institutes and Fac- ulties of Architecture, who by 8th September 2007 have not reached the age of 40. The brief is the design of an INDOOR CHAIR, making significant use of wood. The