A Review of Soy-Tannin Gelling for Resins Applications

Soy flour(SF),soy protein and soy protein isolates(SPI)have been the focus of increasing research on their application as new materials for a variety of applications,mainly for wood adhesives and other resins.Tannins too have been the focus of increasing research for similar applications.While both materials are classed as non-toxic and have achieved interesting results the majority of the numerous and rather inventive approaches have still relied on some sort of hardeners or cross-linkers to bring either of them or even their combination to achieve acceptable results.The paper after a presentation of the two materials and their characteristics concentrates on the formation of gels,gelling and even hardening in the case of soy-tannin combined resins.The chapter than finishes with details of the formation of resins giving suitable wood adhesive of acceptable performance by the covalent coreaction of soy protein and tannin without any other hardener,thus totally bio-sourced,non-toxic and environment friendly as a base of further advances to expect in future by these two materials combination.

Preparation and properties of high-energy-density aluminum/boroncontaining gelled fuels

Energetic nanofluid fuel has caught the attention of the field of aerospace liquid propellant for its high energy density(HED), but it suffers from the inevitable solid-liquid phase separation problem. To resolve this problem, herein we synthesized the high-Al-/B-containing(up to 30%(mass)) HED gelled fuels, with low-molecular-mass organic gellant Z, which show high net heat of combustion(NHOC), density, storage stability, and thixotropic properties. The characterizations indicate that the application of energetic particles to the gelled fuels obviously destroys their fibrous network structures but can provide the new particle-gellant gelation microstructures, resulting in the comparable stability between 1.0%(mass) Z/JP-10 + 30%(mass) Al or B and pure JP-10 gelled fuel. Moreover, the gelled fuels with high-content Al or B exhibit high shear-thinning property, recovery capability, and mechanical strength, which are favorable for their storage and utilization. Importantly, the prepared 1.0%(mass) Z/JP-10 + 30%(mass) B(or 1.0%(mass) Z/JP-10 + 30%(mass) Al) shows the density and NHOC 1.27 times(1.30) and 1.43 times(1.21)higher than pure JP-10, respectively. This work provides a facile and valid approach to the manufacturing of HED gelled fuels with high content of energetic particles for gel propellants.

Preparation and Properties of Embeddable Ag/Ag Cl Gelling Reference Electrode for Rebars Corrosion Monitoring in Concrete

Reference electrodes are a key part for corrosion monitoring and measurement of rebars in concrete. A reference electrode that can be buried in concrete is fabricated by using Ag/Ag Cl electrode and methyl cellulose gelling electrolyte. The stability, repeatability and anti-polarization of the reference electrode are investigated; the influences of the inner electrolyte loss, exterior OH- contamination, and temperature on the potential of the reference electrode are also investigated in this paper. The results show that the reference electrode has good stability, repeatability, and antipolarization. The influences of inner electrolyte loss, exterior OH- contamination, and temperature on the potential of the reference electrode are minimal. Therefore, it can be used for corrosion monitoring and measurement of rebars in concrete.

Encapsulation of Almond Essential Oil by Co-Extrusion/Gelling Using Chitosan as Wall Material

Encapsulation confers protection to substances as essential oils from processes like oxidation, evaporation or uncontrolled release. In this study almond oil capsules were obtained by co-extrusion/gelling technique. Chitosan was used as shell material and sodium triphosphate pentabasic as cross linking agent. Different encapsulation process variables were studied: cross-linker concentration, nozzles size and potential. Optical microscopy was used to determine the capsules morphology and degradability tests were performed in order to study capsules degradation over time. Results showed that nozzles size and cross linking concentration are key variables to consider in the encapsulation process. Degradability tests showed rapid weight loss.

Development and evaluation of Panax notoginseng saponins contained in an in situ pHtriggered gelling system for sustained ocular posterior segment drug delivery

Objective:This study aimed to lay the foundation for the research on Panax notoginseng saponins(PNS)in pH-sensitive in situ gel and the development and improvement of related preparations.Methods:We used Carbopol■940,a commonly used pH-sensitive polymer,and the thickener hydroxypropyl methylcellulose(HPMC E4M)as an ophthalmic gel matrix to prepare an ophthalmic in situ gel of PNS.In addition,formula optimization was performed by assessing gelling capability with the results of in vitro release studies.In vitro(corneal permeation,rheological,and stability)and in vivo(ocular irritation and preliminary pharmacokinetics in the vitreous)studies were also performed.Results:The results demonstrated that the in situ gelling systems containing PNS showed a sustained release of the drug,making it an ideal ocular delivery system for improving posterior ocular bioavailability.Conclusions:This study lays the foundation for the research of PNS contained in an in situ pH-triggered gel as well as the development and improvement of related preparations.It concurrently traditional Chinese medicine with a contemporary in situ gelling approach to provide new directions for the treatment of posterior ocular diseases such as diabetic retinopathy.

The Microstructure and Gelling Mechanism of Thermo-responsive Chitosan Hydrogel System

Thermo-respansive chitosan hydrogel system （TRCHS） was prepared and its mierostructure was investigated by scaning electron microscope （SEM） and mercury intrusion poremaster （MIP）. Based on analyzing the data, a special porosity property was reported at the first time. Its gelling mechanism was studied by a group of contrast experiments. Results may provide experimental and theoretical supports for how to apply it on tissue engineering scaffold and how to influeuee or control its essential properties.

Extraction and characterization of gelling pectin from the peel of Poncirus trifoliata fruit

In the framework of searching for new pectin sources to partially compensate for domestic and regional demands, the peel (albedo) of the “non-comestible” fruit of Poncirus trifoliata was investigated using a relatively simple experimental design for optimization, in which only the variable was the extraction pH (1.0, 1.5, and 2.0) on the basis of our previous studies on diverse pectin sources. The results showed that the yield of pectin (7.4%-19.8%) was strongly influenced by the extraction pH when the other parameters, namely the solid to liquid extractant (S/L) ratio, temperature (T &degC), and time (t) were fixed to 1:25 (w/v), 75&degC, and 90 min, respectively. Likewise, the galacturonic acid content (GalA: 61.4%-79.2%), total neutral sugar content (TNS: 9.1%-22.5%), degree of branching (3.5%-13.9%), homogalacturonan (HG) to rhamnogalacturonan-I (RG-I) ratio (2.2-5.6), degree of methylesterification (DM: 54-77), viscosity average molecular weight (Mν: 57-82), and gelling capacity (GC: 124-158) were all affected by the extraction pH. The optimum pH for producing pectin with good yield, quality characteristics (GalA > 65%, DM > 60, Mν > 80 kDa), and gelling capacity (GC > 150), from the peel of P. trifoliata fruit, was found to be pH 1.5.

Microencapsulation of Rosemary Essential Oil by Co-Extrusion/Gelling Using Alginate as a Wall Material

An essential oil is the volatile lipophilic component extracted from plants. Microencapsulation systems protect the essential oil from degradation and evaporation, and at the same time allow a sustained release. This work analyzed and characterized the rosemary essential oil microcapsules prepared by co-extrusion technique using alginate as wall material and calcium chloride as cross linker. Several instrumental techniques were used: optical microscopy, coulter counter, Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), termogravimetric analysis (TGA), spectrophotometry, antimicrobial test and chromatography. Results show that rosemary oil has pesticidal properties, and its microencapsulation allows knowing that these properties remain inside the microcapsules.

Alumina Ceramics Fabricated by in-situ Consolidation of Pre-gelling Starch

An in-situ consolidation method was developed and optimized to successfully fabricate alumina ceramics using pre-gelling starch. Our results showed that the obtained ceramics have more homogeneous microstructure, higher density, higher flexural strength, and favorable biocompatibility compared to the regular one. During the process, cornstarch granules swelled and deformed but no fracture was observed. After the cornstarch granules bursted, alumina particles were suspended uniformly in the three-dimensional network structure to generate a much smoother surface. Below 0.5 wt% higher cornstarch content increased the flexural strength of prepared ceramics, while above 0.5 wt% the mechanical properties were compromised. Therefore the cornstarch content of 0.5% was the optimal concentration to achieve the highest mechanical strength of the prepared ceramics, with a measured flexural strength of 341 MPa, and a relative density of 96.01%.

Preparation of Microcapsules Containing Artificial Diet for Tropical Fishes with Spray Gelling Method

The microcapsules containing the artificial diet for tropical fishes were prepared with the spray gelling method in order to prevent water environmental pollution. The carboxymethyl cellulose sodium aqueous solution, in which α-tocopherol droplets containing the powdery artificial diet were dispersed, was dropped or sprayed into the chitosan aqueous solution. Microcapsules were prepared by forming polyionic complex shell made from chitosan and carboxymethyl cellulose sodium. In the experiment, the concentration of carboxymethyl cellulose sodium (CMCNa) was mainly changed to investigate the effect on the diameters of microcapsules, the content and the microencapsulation efficiency. The microcapsules couldn’t be prepared with the concentration of carboxymethyl cellulose sodium less than 3.0 wt%. The microcapsules were the core-shell type. The diameters of microcapsules were increased with the concentration of CMCNa and the microencapsulation efficiency of ca. 100% could be obtained by the preparation method presented in this study. The microcapsules were found to be eaten well by tropical fishes and to prevent water environmental pollution.

Gelling Behavior of Plant Proteins and Polysaccharides in Food Systems

Biological macromolecules, such as proteins and polysaccharides, are widely used in food systems because their interactions impart a desirable texture to food products. Plant proteins interact with food components via protein-protein and protein-polysaccharide associations, and the formation of a matrix, which can entrap other food components such as water, lipids and flavors. These networks provide structural integrity to food products and can serve as important functional ingredients in processed foods. Intermolecular interactions of typical polysaccharides result either in simple associations or in the form of a double or triple helix. The linear double helical segments may then interact to form a super junction and a three-dimensional gel network. The formation of these structural networks takes place during processing and involves the transformation from a liquid or viscous sol into a solid material with elastic properties. Interests in the behavior of mixed gels center on the prospects of enhanced flexibility in their mechanical and structural properties compared to those of pure gels. Findings on molecular interactions between plant proteins （e.g., soy, canola and pea proteins） and polysaccharides （e.g., guar gum, carrageenan, and pectin） allow for the modification of physical and textural characteristics of mixed biopolymers to meet desired functional property.

海藻酸钠改性垃圾焚烧底灰-矿渣基胶凝堵漏材料研究

针对传统矿用水泥基堵漏材料存在的收缩开裂、高能耗及高碳排放的问题,探索采用海藻酸钠(SA)交联金属离子,制备SA改性垃圾焚烧底灰(MSWI-BA)-粒化高炉矿渣(GBFS)基胶凝堵漏材料(SWM)。通过抗压强度和凝结时间的测试,确定了最佳水固比为0.4。通过胶凝材料在不同温度下的抗压强度、收缩率及裂缝形貌的分析,探究了SA改性对胶凝材料的耐高温性能的影响,结果表明SA改性后,胶凝材料的耐高温性得到了改善,受热后改性胶凝材料表面裂缝明显减少,收缩率较改性前最大降低了26.5%,在400℃受热后,剩余抗压强度仍高达17.25 MPa。结合微观形貌、孔结构性能和热分析实验,探究了SA改性胶凝材料的形成机理,结果表明,SA改性MSWI-BA-GBFS基胶凝堵漏材料通过SA与底物中的Ca^(2+)/Al^(3+)的配位交联与碱激发底物形成的硅铝酸盐共价网络协同作用,细化孔径,减小孔容,在受热后保持基体结构的完整性,从而改善胶凝材料的抗收缩开裂性。堵漏风模拟实验结果表明,水固比0.4的SA改性MSWI-BA-GBFS基胶凝堵漏材料的堵漏性能优于矿用水泥基材料,表现出较好的堵漏性能。SA改性MSWI-BA-GBFS基胶凝堵漏材料的研制不仅为城市垃圾焚烧底灰的资源化利用提供了有效途径,还提供了一种抗压强度高、抗收缩开裂且耐高温的可以完全替代传统矿用水泥基堵漏材料的环保防灭火材料。

聚氨酯固化钙质砂物理力学特性

聚氨酯加固是一种新型环保快速的土质改良方法。针对南海钙质砂采用聚氨酯快速改良,并通过室内试验验证该处置方法的有效性和适用性。通过对聚氨酯固化钙质砂试样开展无侧限抗压强度试验、静力荷载和循环荷载下的三轴试验以及渗透试验,研究聚氨酯固化钙质砂的最佳凝胶时间,静、动强度特性及渗透特性。试验结果表明:固化试样的最佳凝胶时间为6.5 h;随着掺量的增加,固化钙质砂黏聚力得到显著提高,内摩擦角基本保持不变,在海水环境养护下的聚氨酯钙质砂仍然保持了较高的强度;随着掺量的增加,聚氨酯钙质砂的初始动剪切模量增加,最大阻尼比降低;钙质素砂渗透系数的数量级为10^(-6),掺入2%~10%聚氨酯后数量级降至10^(-8)~10^(-7),聚氨酯补漏效果较好。

甜菜碱型疏水缔合胶凝剂的制备及其性能评价

当前在碳酸盐岩酸化压裂改造中应用的主要添加剂(胶凝剂)逐渐不能满足储层改造的需要。为此,文中以N-甲基牛黄酸钠、烯丙基氯、棕榈酰氯和三乙胺为原料,在二氯甲烷溶剂中,通过两步法制备出一种含磺酸根离子和季铵盐的甜菜碱型疏水单体(TSM-16);并以TSM-16和丙烯酰胺(AM)为原料,采用自由基水溶液聚合法合成了一种新型胶凝剂(PAT),且与常规胶凝剂(PAA)进行了综合性能对比。结果表明,相较于PAA,由于PAT具有疏水链段和两性离子基团,它在酸液中表现出更优异的酸稳定性、热稳定性、剪切稳定性和缓速性能,在酸化压裂领域中具有良好的应用前景。

不同活化方式下硅质铁尾矿的粉磨特性与胶凝活性

机械活化是提高尾矿活性的常用方法,将化学活化剂加入粉磨体系中的机械-化学活化方式是更为有效的手段.使用5种活化剂,采用了单掺和复配的方式对硅质铁尾矿(iron ore tailings,IOTs)粉磨特性及早期胶凝活性的影响进行对比分析.通过机械活化、机械-化学活化2种方式制备铁尾矿粉,测定2种活化方式磨细后IOTs的粉磨特性——比表面积、颗粒粒径分布(PSD)及3,7,28 d胶凝活性,利用XRD和SEM分析水化产物.结果表明:在相同的粉磨时间内,各活化剂的加入均能提高IOTs比表面积,粉磨90 min时添加复合活化剂的机械-化学活化与机械活化相比最多提高30.43%;活化剂的加入提高IOTs粉磨效率使PSD区间更窄;水化早期胶凝体系的强度提高主要是活化剂可促进钙矾石形成,后期强度提高是因为尾矿活性提高.本研究对硅质铁尾矿的高效利用具有重要意义.

早强型钢渣基胶凝材料的制备及其水化机理研究

钢渣是炼钢过程中产生的主要废弃物,具有用途单一、产生量大、污染环境等特点。本文使用钢渣微粉、42.5普通硅酸盐水泥分别与增强剂Ⅰ、增强剂Ⅱ混合制备早强型钢渣基胶凝材料,通过测定原料化学成分、矿物组成,测试胶凝材料的力学性能,分析其热稳定性、微观形貌来揭示胶凝材料的水化机理。研究结果表明:胶凝材料的早期抗压强度大幅提高,后期抗压强度良好;这是因为增强剂能促进Ca(OH)2消耗并提高水化反应速率,Ca(OH)2水解出的OH-能促进钢渣微粉中玻璃体溶出硅酸盐,与Ca^(2+)生成C-S-H凝胶;增强剂含有的硫酸盐能与胶凝材料生成钙矾石AFt,并填充于凝胶孔隙中,增强了材料的密实度。早强型钢渣基胶凝材料的最优配比为钢渣微粉125 g、增强剂Ⅱ用量10 g。研究成果为早强型钢渣基胶凝材料的制备提供了新思路,也可为钢渣综合利用研究提供借鉴。

油凝胶替代脂肪的研究及在植物肉饼中的应用

本研究以菜籽油和椰子油为油相,以单甘酯(monoglyceride,MG)、蜂蜡、米糠蜡、巴西棕榈蜡、小烛树蜡(candelilla wax,CLW)为凝胶剂制备油凝胶,探究不同添加量(5%、10%、15%、20%)凝胶剂对油凝胶持油力、质构特性、流变学性质的影响。结果表明,当凝胶剂添加量为15%及以上时,油凝胶的持油力均达到96%以上;MG的融化特性与牛油最为相似,但单一凝胶剂制备的油凝胶难以模仿牛油的质构性质。因此,本实验固定凝胶剂添加量为15%,选用不同质量比的MG和CLW复配制备油凝胶,并用于制备植物肉饼。结果表明,当MG与CLW复配比为3∶7时,油凝胶的质构性质、流变学性质最接近牛油,植物肉饼的感官品质最佳,显示出较好的脂肪替代潜力。

基于FPGA的La Gell5/3小波变换的硬件电路设计

为了对冗余的图像数据进行有效的压缩,提出一种基于FPGA的快速小波变换的方案。介绍了La Gell 5/3提升小波变换的原理,设计了适用于高帧频CMOS相机的La Gell 5/3提升小波变换硬件结构,采用Verilog硬件语言在QuartusII软件平台下对设计方案进行了实验,利用Matlab语言对图像进行反变换,并通过变换前与反变换后图像的比对,验证了算法的可行性。实验结果证明:该方案成功实现了基于FPGA的La Gell 5/3提升小波变换系统对给定图像的三级快速小波变换,相比较于DSP等硬件电路,更适合于高速图像实时处理的应用。

凝胶推进技术研究进展

凝胶推进技术是指在液体燃料中加入合适的胶凝剂形成三维网络以转变为半固体半液体状态,通过控制推进剂流量实现推力可调的一类推进技术。凝胶推进剂具有比冲大、安全性高和易于储存等优良性能。从凝胶推进剂的胶凝剂种类、流变特性、雾化特性、液滴燃烧特性和应用前景等方面进行了梳理和总结,提出了今后研究的重点并展望了未来发展方向,即制备对外界刺激敏感的凝胶推进剂、改善凝胶推进剂供给环境和雾化模式、建立凝胶推进剂液滴燃烧模型、设计和开发适用于空间任务的凝胶微推进系统等。

Gelled Ionic Liquid/PMMA Polymer Electrolyte Prepared by Radical Polymerization

The gel polymer electrolyte containing N-propyl, methylpyrrolidinium bis（（trifiuoromethyl） sulfonyl）imide （PYR13TFSI） with better performance is prepared by radical polymerization method. The interface status between the LiFePO4 electrode and the electrolyte is characterized by a scanning electron microscope and X-ray photoelectron spectroscopy （XPS）. There is a layer of membrane on the gel electrolyte and perfect shell membranes on the surface of active LiFePO4 cluster, on the other hand, N and S photoelectron signals are observed in XPS spectra after charge-discharge cycles. The results show that the ionic liquids and unpolymerized methyl methacrylate incorporate into the electrode surface and form the SEI membrane with Li ion and electrons while the gel electrolyte contacts with the electrode. The formation process of the SEI membrane needs at least three cycles, the discharge capacity increases as the SEI membrane becomes sufficiently thick, which blocks further electron transfer, and the system may approach steady state. The performance of cell with ionic liquid gel polymer electrolyte is measured at different rate. The cells retain 132 mAh/g at 0.2 C, 128 mAh/g at 0.5 C, and 120 mAh/g at 1.0 C after 30 cycles with charge-discharge efficiency of ca. 98% at every rate.