Seed oils rich in linolenic acid as renewable feedstock for environment-friendly crosslinkers in powder coatings

In the work described, seed oils rich in linolenic acid were used for the synthesis of aliphatic oxiranes. The oils studied were linseed (Linum usitatissimum) oil, Canadian linseed oil and the oil of Lallemantia iberica. The oils contained 54.1, 60.2 and 68.0% of linolenic acid, respectively, and showed high theoretical iodine values of 211, 226 and 236 g/hg. Unsaturations in the oils were used to introduce epoxides by epoxidation with in situ generated peroxyacetic acid. The epoxidized oils, showing high percentages of oxirane oxygen (9.4, 10.0 and 10.7%), were applied as crosslinkers in powder-coating formulations. The major advantage of these types of crosslinkers is that they are neither toxic nor mutagenic, in contrast with the widely applied synthetic triglycidyl isocyanurate (TGIC) crosslinkers. However, two potential problems exist when aliphatic oxiranes are compared with conventional TGIC systems. A decrease in glass transition temperature (T_g) of the powder formulation and a higher degree of yellowing of the coating are often observed. In this paper the effects of using oils containing high linolenic acid contents on the yellowing of the coating and the T_g of the powder, are studied. It appeared that aliphatic oxiranes are suitable as environment-friendly crosslinkers in powder-coating systems.     

稻瘟病持久抗性在三系杂交稻上的导入

 选用稻瘟病抗源外选35及其衍生系统持久抗性品种三黄占2号、三芦占7号、梅三五2号及其衍生品种矮三芦占、七黄占2号、七袋占分别与野败型不育系博A、优ⅠA、Ⅱ优A、红莲型不育系广A配制共28个组合。以IR36为抗性对照,广陆矮4号为感病对照,对杂交组合及其不育系（保持系）和抗性品种进行了人工接种稻瘟病菌抗谱测定,数量抗性测定和不同病区田间异地同步抗性鉴定。抗性分析和比较结果表明：具持久抗性品种三黄占2号、三芦占7号配制的杂交组合表现了与持久抗性品种相同的表型特征,即表现较高的质量抗性和数量抗性, 较好的田间抗性。初步认为：三黄占2号和三芦占7号的持久抗性能导入三系杂交稻组合中。     

Incorporation of aliphatic units into aromatic water-soluble polyesters to improve the performances for warp sizing

Aliphatic units (ethylene succinate) were incorporated into aromatic water-soluble polyesters (WSP) in order to improve their environmental protection and sizing performances. The environmental performance was measured in terms of biological oxygen demand for 5 days (BOD₅) and chemical oxygen demand (COD). Apparent and intrinsic viscosities, the adhesion to polyester fibers, glass transition temperature, and mechanical behavior of sizing films of WSP were evaluated for improving their sizing performance. The composition of copolymeric WSP was also investigated by ¹H-NMR. A series of copolymeric WSP with a variation in molar ratio of aliphatic monomer (dimethyl succinate) to aromatic monomer (dimethyl terephthalate) from 10:90 to 40:60 was synthesized through a two-step reaction, transesterification and polycondensation. It was found that, by incorporating aliphatic units into the macromolecular chain of aromatic WSP, the environmental performance, apparent and intrinsic viscosities, and the toughness of sizing film were enhanced obviously. The adhesion to polyester fibers showed no sensitivity to the molar ratio of dimethyl succinate to dimethyl terephthalate when the ratio ranged from 10:90 to 30:70. In view of overall performance of the aliphatic-containing WSP sizes, the molar ratio should be 30:70. Based on the ratio, the WSP prepared showed better environmental and sizing performances.     

Incorporation of Functionalized Silica Nanoparticles into Polymeric Films for Enhancement of Water Absorption and Water Vapor Transition

Water absorption and water vapor transition are significant mechanisms in many industrial processes. Nanocomposite polymers are appropriate materials for water transition process due to their specific properties. The present work was aimed to enhance the water absorption and water vapor transition by high loading incorporation of silica nanoparticles (NPs) into polyacrylonitrile (PAN) and Pebax 1657 polymers. PAN was used to prepare both the nanocomposite films (NCFs) and support layers of nanocomposite membranes (NCMs). Pebax 1657 was used to fabricate the selective layers of NCMs. Incorporation of NPs into the NCFs were carried out using ex-situ and in-situ (sol-gel) methods. NCFs were fabricated by electrospinning and casting methods. The fabricated NCFs of fibers and polymers were examined through water absorption tests. For fabrication of NCMs, the electrospinning and dip-coating methodologies and the incorporation of NPs into the selective layers by in-situ method were used. Besides, the water vapor permeation tests have been designed and constructed to examine the NCMs for dehydration of methane gas. In order to provide efficient NPs dispersion into NCFs, the surface functionalization of silica NPs with ethylene glycol (EG) was also considered. The functionalized silica NPs were used in the fabrication of NCFs and into the selective layer of NCMs. It is found that in applying the ex-situ method, there is a lot of NPs agglomeration, while the dispersion quality of NPs is higher with the sol-gel method. In addition, the dispersion is improved greatly with functionalization of silica NPs. The water uptake ratio of electrospun mats is about 400 % higher than the cast layers for the same loadings of NPs. The water uptake ratio of the polymeric layers containing EG is about 50 % higher than the samples without EG. The permeance of water vapor for the NCM (15 wt.% of SiO₂/Pebax 1657) fabricated by sol-gel method was enhanced to 54.4 % higher than the membranes without NPs. Functionalization of silica NPs also enhanced the water vapor permeation process. For instance, the water vapor of the NCM containing 30 wt.% of EG/Pebax1657 was increased by 68.7 %.     

Selective separation of bifenthrin by pH-sensitive/magnetic molecularly imprinted polymers prepared by pickering emulsion polymerization

Via Pickering emulsion polymerization, pH-sensitive magnetic molecularly imprinted polymers (HM-MIPs) were synthesized using bifenthrin (BF) as the template molecule, and pH-sensitive monomer methacrylic acid as the functional monomer. Characterizations of HM-MIPs were achieved by FTIR, TGA, TEM, SEM, and VSM, and the results indicated that HM-MIPs exhibited magnetic property (Ms=1.06 emu/g). HM-MIPs were acted as the adsorbent for a series of adsorption performance testing of BF. Equilibrium data were described by the Langmuir and Freundlich isotherm models. Kinetic properties were successfully investigated by pseudo-first-order model, pseudo-second-order model. The selective recognition experiments exhibited outstanding selectively adsorption effect of the HM-MIPs for target BF over diethyl phthalate and fenvalerate. In water, the HM-MIPs could achieve the adsorption and release of BF by controlling the pH value of the aqueous solution. The results indicated that the molecularly imprinted polymers exhibited good adsorption, selectivity and pH-sensitive performance for BF.     

Incorporation of high-molecular-weight glutenin subunits into doughs using 2 gram mixograph and extensigraphs

To study the contributions of high-molecular-weight glutenin subunits (HMW-GS) to the gluten macropolymer and dough properties, wheat HMW-GS (x- and y-types) are synthesized in a bacterial expression system. These subunits are then purified and used to supplement dough mixing and extensigraph experiments through dough partial reduction and reoxidation to allow these exogenously added HMW-GS to incorporate into gluten polymers. Detailed results are given for seven mixing and two extension parameters. HMW-GS synthesized in bacteria behaved similarly under these conditions to the same HMW-GS extracted from wheat flour. These experiments initially focused on the HMW-GS of the D-genome of hexaploid wheat encoded at the Glu-D1 locus; e.g. the Dx2, Dx5, Dy10, and Dy12 subunits. Experiments used five different flours and results are shown to be consistent when normalized to results from Dx5. The incorporation of Dx-type subunits into the gluten disulfide bonded network has greater effects on dough parameters than incorporation of Dy-type subunits. When Glu-D1 x- and y-type subunits are incorporated together, there are synergistic effects greater than those with either subunit type alone. This synergistic effect was greatest with approximately equal amounts of Dx- and Dy-type subunits - implying a 1:1 stoichiometric relationship.     

稻瘟病持久抗性在三系杂交稻上的导入续报

 选用稻瘟病持久抗性载体品种三黄占２号、三芦占7号,稻瘟病抗性品种外选35和矮三芦占等4个品种,与广A、博A两个不育系配组8个组合,重复进行了详细的稻瘟病抗谱测定、数量抗性测定以及不同病区田间异地同步抗性鉴定,结果表明：（１）三黄占２号、三芦占7号携带的稻瘟病持久抗性基因能在三系杂交稻组合中表达出来,杂交稻的持久抗性育种是可能的;（2）与常规稻类同,数量抗性和不同病区田间异地同步抗性可作为区分杂交稻是否具有持久抗性的指标;（3）数量抗性与不同病区田间异地同步抗性紧密正相关,数量抗性可作为区别高质量抗性组合是否具有持久抗性的重要依据,可以应用温室人工鉴定的数量抗性指标开展稻瘟病持久抗性育种探索。     

A study of the drying of linseed oils with different fatty acid patterns using RTIR-spectroscopy and chemiluminescence (CL)

The oxidative drying of two different linseed oil coatings with either high content of linoleic or linolenic fatty acids have been studied. The curing performance has been followed by a combination of two different analytical techniques, real-time infrared (RTIR) spectroscopy and chemiluminescence (CL) at different temperatures. The effect of a metal drier on the drying process has also been evaluated. The purpose was to reveal how structural variations can improve the drying performance and film properties for oxidative drying linseed oil coatings.The reaction rate is increased for both oils with increased temperature as expected. The oil rich in linolenic acid reacts more rapid and exhibits shorter induction times compared to the oil rich in linoleic acid. The addition of a metal drier further accelerates the drying but in a different manner for the different oils. The oil high in linolenic acid oxidizes so rapidly that a skin layer, acting as a diffusion barrier to atmospheric oxygen, is formed. The through drying rate is then strongly reduced, leaving high levels of residual unsaturation in the film. As a consequence, this will generate poor ageing properties. The oil richness in linoleic acid shows, much better through drying properties even when the reaction is accelerated by both the use of a metal drier and high temperatures. The consequence is that the linseed oil high in linoleic acid can be cured rapidly with good through drying and low levels of residual unsaturations.The combination of the two analytical techniques gives complementary information of the drying mechanisms of the linseed oils. The techniques are shown to be very useful when following oxidative drying of thin films.     

Evaluation of land use change and groundwater use impact on stream drying phenomena using a grid-based continuous hydrologic model

The effect of land use change on drying streams was evaluated using a grid-based continuous hydrological model (PGA-CC). For a drying stream-progressed watershed (398.8 km²), the model was calibrated and validated using 7 years (2005–2011) of streamflow data at the watershed outlet with an average Nash–Sutcliffe model efficiency of 0.71. Based on the model simulation results for 36 years (1976 to 2011), both land use change and climate change decreased the 10-day minimum flow by 0.16 m³/s and increased the day counts below the annual average by 40.6 days/year. These changes resulted from the 8.7 % increase in urban area, 1.43-fold increase in groundwater use, and 1.1 °C temperature increase during the 36-year period. From the distributed results of the model, we identified the drying stream location and progression. The spring and winter seasons were relatively strongly affected, and drying streams were identified in more urbanized areas with greater groundwater use.     

A review on the use of essential oils for postharvest decay control and maintenance of fruit quality during storage

Postharvest diseases are one of the major causes for the postharvest loss of horticultural fresh produce during the supply chain. The incidence of postharvest diseases can affect the quality and restrict the shelf life of the horticultural fresh produce. At present strict regulations are enforced by the fresh produce importing countries regarding the minimum pesticide residue levels in the edible portion of the fresh produce. Some fungal pathogens were reported to develop resistance to synthetic fungicides. Waste disposal of fungicides has an impact on environmental footprint. All theses above-mentioned reasons have necessitated the search for a natural novel fungicide to replace the synthetic fungicide application in the packing line as postharvest treatment.Consumer preference to organic fresh produce is increasingly becoming popular in the developed countries. Therefore, this review summarises the use of essential oils in the control of postharvest diseases of horticultural commodities, their mode of actions, effects on the defence mechanism and quality of fresh fruit. Future research must be focused on conducting large scale trials to prove the feasibility of combination treatments. The cost benefit analysis of the treatments needs to be carried out in order to implement their application and the commercial applications of essential oils and host pathogen infection must be investigated in detail in order to control latent infections during postharvest storage.     

外源基因导入水稻育种技术研究进展与应用

介绍了外源基因导入水稻技术研究的新进展及其在水稻育种中的应用 ,同时进一步阐述了外源基因导入技术改良水稻品种的趋势与前景。     

压力喷雾干燥系统在速溶茶粉生产中的应用

以CGYP01—500型立式压力喷雾干燥系统在速溶茶粉生产中的应用为例,介绍目前国内喷雾干燥系统的选择、确定、应用及生产中常见问题的处理。速溶茶粉密度小、易吸潮,单级滤袋或旋风捕粉的压力喷雾干燥系统在速溶茶粉生产中尚存在不足,两级捕粉式的压力喷雾干燥系统在速溶茶粉生产中应用效果较好。     

Effects of partial root-zone drying on yield,tuber size and water use efficiency in potato under field conditions

Water resources are limited for irrigation worldwide; therefore, there is a need for water-saving irrigation practices to be explored. Partial root-zone drying (PRD) is a new water-saving irrigation strategy being tested in many crop species. Experiments were conducted in potato (Solanum tuberosum L. cv. Folva) under open field conditions in 2004 and under a mobile rainout shelter in 2005. Two subsurface irrigation treatments were studied: full irrigation (FI) receiving 100% of evaporative demands, 50.1 and 201 mm of irrigation water in the 2 years, to keep it close to field capacity; and PRD, which received 21.7 and 140 mm of irrigation in 2004 and 2005 respectively. Due to rain in 2004, the PRD treatment was imposed over a short period only during the late tuber filling and maturing stages. In 2005, the PRD treatment was imposed during the whole period of tuber filling and tuber maturation. The PRD treatment was shifted from one side to the other side of potato plants every 5–10 days. Especially in 2005 it was apparent that stomatal conductance was generally lower in the PRD than in the FI plants, whereas leaf water potential tended to be lower in only a few instances. During the treatment period, plants were harvested five times, and no significant difference was found between the treatments in leaf area index, top dry mass and tuber yield. At final harvest, tubers were graded based on size into four classes C₁–C₄, of which the yield of the important marketable class (C₂) was significantly higher (20%) in the PRD than in the FI treatment. Compared with FI, the PRD treatment saved 30% of irrigation water while maintaining tuber yield, leading to a 61% increase of irrigation water use efficiency. The limited data of 2004 support these results. In summary, PRD is a promising water-saving irrigation strategy for potato production in areas with limited water resources.     

Comparison of haymaking strategies for cow-calf systems in the Salado Region of Argentina using a simulation model. 2. Incorporation of flexibility into the decision rules

In pastoral farming systems, pasture production normally exceeds demand in the spring–summer period. Consequently, conserving forage at this time for use during the following winter is a widespread practice. The objective of this study was to assess the possible advantages of incorporating flexibility into a calendar‐based haymaking policy. A range of flexible haymaking strategies were simulated and compared against a calendar‐based strategy by using a simulation model to estimate long‐term performance of cow‐calf farm systems under each strategy. The results suggest that controlling haymaking in a flexible fashion, basing the decisions of closing, releasing and cutting paddocks on a simple pasture budget, could give the system productive advantages over using a calendar‐based approach. In terms of liveweight production per hectare, compared at the same area harvested, the flexible approach had higher average annual calf liveweight production (an increase of up to 0.15) and lower system variability [a reduction of 0.10 in the coefficient of variation (CV)] depending on the stocking rate. The results indicated that allocating more than 0.50–0.60 of the farm area to conservation would only be advantageous at very high stocking rates. In contrast to the calendar‐based strategy, making more hay than required for the immediate next winter, where possible, can reduce system variability.     

Thin-layer drying kinetics and quality changes of sweet sorghum stalk for ethanol production as affected by drying temperature

The chopped sweet sorghum stalk was thin-layer-dried for long-term storage and ethanol production. The drying kinetics and the effects of drying temperature on the qualities of sweet sorghum stalk were investigated in this work. The results showed that the drying process could be simulated well by Wang and Singh's model. The diffusivity constant (D₀) and active energy (E_a) were estimated as 4.4 × 10⁻⁵ m²/s and 21.4 kJ/(mol K) for drying the chopped fresh stalk. According to the sugar composition, browning degree, and fermentability of the dried stalk obtained at various temperatures, the approximate drying temperature could be suggested as 50-60 °C for application. In this range, the moisture of the chopped fresh stalk could drop below the safe moisture for storage in 7-5.5 h with 12.1-9.7% total sugar loss during the drying process.     

Properties of polymers as a nanoscale material for fibers in leather

Hyperbranched polymers, an innovative class of nano-polymers, could enhance the properties of fibers owning to their unique structures. In this study, the ester compound (HPAE) of 3-(bis(2-hydroxyethyl)amino)propionic acid and pentaerythritol was treated with undecylenic acid to obtain novel hyperbranched multiterminal alkenyl polymers (HPAE-UAs). The sizes of the HPAE-UAs could be controlled conveniently from 400 to 1300 nm by adjusting the capped fraction of the hydroxyl groups with undecylenic acids. The molecular structures of HPAE-UAs were characterized by means of FT-IR and ¹H-NMR. Then, the effect of the HPAE-UAs on the structures, thermal, and mechanical properties of the wet blue leather were investigated. TEM and SEM demonstrated that the spacing between fibers was enlarged. The thermogravimetric analysis showed that the residual volume of leather could reach up to 30.3 % at about 500 °C. Furthermore, the shrinkage temperature increased to 89.4 °C. It was found that the HPAE-UAs used in leather could improve the thermal performance, physical and mechanical properties. All of these results indicate that HPAE-UAs can be used as a fatliquor with retanning in leather process.     

Effect of contact angle hysteresis on the removal of the sporelings of the green alga Ulva from the fouling-release coatings synthesized from polyolefin polymers

Wettability is one of the surface characteristics that is controlled by the chemical composition and roughness of a surface. A number of investigations have explored the relationship between water contact angle and surface free energy of polymeric coatings with the settlement (attachment) and adhesion strength of various marine organisms. However, the relationship between the contact angle hysteresis and fouling-release property is generally overlooked. In the present work, coatings were prepared by using commercial hydrophobic homopolymer and copolymer polyolefins, which have nearly the same surface free energy. The effects of contact angle hysteresis, wetting hysteresis, and surface free energy on the fouling-release properties for sporelings of the green alga Ulva from substrates were then examined quantitatively under a defined shear stress in a water channel. The ease of removal of sporelings under shear stress from the polymer surfaces was in the order of PP>HDPE>PPPE>EVA-12 and strongly and positively correlated with contact angle and wetting hysteresis; i.e., the higher the hysteresis, the greater the removal.     

Incorporation of surface modified graphene nanoplatelets for development of shape memory PLA nanocomposite

In this study, a temperature sensitive shape memory polymer (SMP) system based on polylactic acid (PLA) has been developed and the effect of graphene nanoplatelets (GNPs) on the shape memory properties was evaluated. Dispersion of GNPs in PLA was improved with the aid of a zwitterionic surfactant. X-ray diffraction (XRD) and transmission electron microscopy (TEM) showed that the surface modified graphene nanoplatelets (SMGNPs) were exfoliated and homogenously dispersed in the PLA matrix due to enhancement of the polymer-graphene interaction. Mechanical properties of the samples namely stiffness and elasticity were increased upon incorporation of graphene nanoplatelets accompanied by their good dispersion in the PLA matrix. Furthermore, differential scanning calorimetry (DSC) revealed that the nucleation effect of graphene promote the crystallization and noticeably enhanced the degree of crystallinity. Finally, prominent mechanical properties along with high degree of crystallization due to fine dispersion of surface modified graphenes, resulted in drastic improvement in shape memory performance.     

Effect of the drying rate on the complex viscosity of wheat flour dough transforming into crust and crumb during baking

This study aimed at characterizing the effect of hydrothermal dynamics on the dough rheology, in order to develop a complete dough viscosity model valid at different locations during baking. The dough rheology was characterised using dynamic mechanical thermal analysis (DMTA). Temperature and water content (WC) were monitored during DMTA. At high heating rates (15–30°C/min), relevant to the top crust, viscosity behaved as if WC was kept constant, in spite of dehydration (37%); such similarity was valid up to 80°C (stage A). Beyond, the viscosity decrease observed in the samples at constant WC was replaced by a long-lasting plateau (stage B, 3–4 × 10⁶ Pa.s), attributed to WC reduction below ∼37%. Above the boiling water temperature, the logarithm of viscosity increased linearly with decreasing WC (stage C). At lower heating rates (5°C/min), relevant to the bottom crust, viscosity was two-fold higher than that at higher heating rates, suggesting lower oven-rise. The viscosity decrease, observed at high temperatures (>80°C) for samples at constant WC, was not observed if drying occurred late (case of crumb beneath the crust); instead, viscosity increased up to levels close to that of the top crust (2–3 × 10⁷ Pa.s at WC∼20%). Despite these deviations, viscosity as a WC function was modelled with a unique equation set.