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.

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.

Interface property of dissimilar Ti-6Al-4V/AA1050 composite laminate made by non-equal channel lateral co-extrusion and heat treatment

The purpose of this paper is to examine the effect of processing parameters and subsequent heat treatments on the microstructures and bonding strengths of Ti-6Al-4V/AA1050 laminations formed via a non-equal channel lateral co-extrusion process.The microstructural evolution and growth mechanism in the diffusion layer were discussed further to optimize the bonding quality by appropriately adjusting process parameters.Scanning electron microscopes(SEM),energy dispersive spectrometer(EDS),and X-ray diffraction(XRD)were used to characterize interfacial diffusion layers.The shear test was used to determine the mechanical properties of the interfacial diffusion layer.The experimental results indicate that it is possible to co-extrusion Ti-6Al-4V/AA1050 compound profiles using non-equal channel lateral co-extrusion.Different heat treatment processes affect the thickness of the diffusion layer.When the temperature and time of heat treatment increase,the thickness of the reaction layers increases dramatically.Additionally,the shear strength of the Ti-6Al-4V/AA1050 composite interface is proportional to the diffusion layer thickness.It is observed that a medium interface thickness results in superior mechanical performance when compared to neither a greater nor a lesser interface thickness.Microstructural characterization of all heat treatments reveals that the only intermetallic compound observed in the diffusion layers is TiAl_(3).Due to the inter-diffusion of Ti and Al atoms,the TiAl_(3) layer grows primarily at AA1050/TiAl_(3) interfaces.

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.

Effect of hydro co-extrusion on microstructure of duo-cast Al3003/Al4004 clad materials

The effects of hydro co-extrusion on the microstructure changes of aluminum hybrid duo-cast Al 3003/Al 4004 clad materials were studied. The specimen of duo-cast Al 3003/Al 4004 clad materials was in circle shape, and was composed of Al 3003(outside) and Al 4004(inside) materials. The specimen was extruded by the hydro co-extrusion equipment. The manufacturing conditions of the specimen were 423 K in temperature and 5 in extrusion ratio. The dimensions of the specimen were 80 mm in diameter of the Al 4004 material and 35 mm in thickness of the Al 3003 material before the hydro co-extrusion process, and 30 mm in diameter and about 5 mm in thickness after the extrusion process, respectively. The microstructure and the hardness for two specimens were investigated. The hardness value of cross section in the duo-cast Al 3003/Al 4004 clad materials before the extrusion process was increased in form of the parabola toward the center. However, after the extrusion process, it was almost constant in the portion of Al 4004 material. Lots of big voids above 1 mm in diameter in the specimen existed in the interfacing region of Al 3003 and Al 4004 materials before the extrusion process. These big voids disappeared after the process of hydro co-extrusion.

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.

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.

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.

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.

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.

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。

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.

钢渣特性随粒级分布的规律研究

易磨性差、安定性不良、胶凝活性低是制约钢渣在建材领域资源化利用的主要问题。本工作将不同预处理的钢渣分级成0~0.6 mm、0.6~2.36 mm、2.36~4.75 mm、4.75~9.5 mm粒级,研究了不同粒级钢渣的化学成分、矿物组成、易磨性、安定性、胶凝活性及其之间的相互关系。结果表明:钢渣易磨性随钢渣粒级的增加而变差,这是因为难磨物相钙铁石(Ca_(2)Fe_(2)O_(5))、RO相(MgO·2FeO)含量随粒级的增加而增加,细粒级钢渣f-CaO含量、沸煮膨胀值、压蒸粉化率均低于粗粒级钢渣,陈化钢渣以及热闷钢渣中0~0.6 mm粒级钢渣赋存f-CaO含量最少。钢渣胶凝活性随粒级的增加呈现出先增大后减小的趋势,其中2.36~4.75 mm粒级钢渣最优,钢渣中的C_(3)S、C_(2)S含量提高有利于钢渣胶凝活性的增长。不同粒级钢渣化学成分、矿物组成与钢渣易磨性、安定性、胶凝活性之间具有良好的线性相关性。

基于污泥的多元固废体系混凝土性能研究

为缓解水泥生产和污泥等固废处理带来的环境退化和资源浪费问题,该文以硅灰、粉煤灰、矿渣和玻璃粉4种固废为研究对象,与污泥构成二元、三元胶凝材料替代体系,通过改变体系内固废种类及掺加比例,共替代20%的水泥,设计12个配合比。从抗压强度、表观密度和吸水率3个方面进行宏观分析,利用核磁共振显微检测、扫描电子显微镜(SEM)和X射线衍射法(XRD)三种方式进行微观结构分析,探究二元、三元胶凝材料替代体系的力学性能。试验结果表明:三元胶凝材料替代体系的力学性能远优于二元胶凝材料替代体系。污泥-硅灰-粉煤灰替代体系替代效果最优,抗压强度相较于对照组A1和A2分别提高4.2%和12.5%,这是因为硅灰和粉煤灰混合对污泥有更好的激发作用使其参与水化反应,生成较多钙矾石(AFt)和C-S-H凝胶体等水化产物,使微观物相和孔隙结构均得到提升。研究可为污泥等固废的资源化利用提供参考。

基于原位微观图像的含蜡原油析蜡胶凝过程

原油的流变性是石油开采、输运过程关注的基础物性,含蜡原油具有复杂的低温流变特性,而蜡的析出是决定原油低温胶凝和复杂流变性的内因。采用可以记录蜡晶微观结构实时演变过程的原位显微观测技术,以大庆原油为考察对象研究了含蜡原油降温析蜡胶凝过程蜡晶微观形貌变化。结果表明:大庆原油在实验温度34~60℃范围内降温过程中,蜡晶数量和面积先缓慢增加后以近似指数形式增加,平均长径比由波动逐渐趋于稳定,分形维数由降温初始阶段波动式增加过渡到后续的线性增加。在降温的开始阶段,降温速率(0.25、0.50、1.00、1.50、2.00℃/min)和加热温度(50、55、57、60、65℃)对蜡晶析出生长过程影响不明显;随着降温的持续,降温速率的减小或加热温度的升高,蜡晶数量和蜡晶面积均大幅增大。蜡晶微观参数在65℃发生突变,这与宏观流变实验的改性加热温度相吻合。含蜡原油降温析蜡胶凝过程的蜡晶生长规律为含蜡原油复杂宏观流变性深入研究及改性输送技术提供理论基础。

钢渣粉固化改良膨胀性黏土机理研究进展

在长期湿热环境下,膨胀性黏土易发生路基变形、边坡失稳和滑坡崩塌等地质灾害。因此,有必要深入分析钢渣粉(steel slag powder,SSP)改良膨胀性黏土的宏观和微观特性,以解决相关工程问题,并推动钢渣的高值化和资源化利用。文章全面回顾了SSP改良膨胀性黏土的研究现状,系统归纳了SSP的理化特性和胶凝活性,阐述了碱激发剂对SSP活性的激发原理,揭示了SSP改良膨胀性黏土的微观机制和力学特性。主要结论如下:(1)SSP含有丰富的活性矿物成分,能够与黏土颗粒发生离子交换及水化反应,从而改变黏土微观结构和理化性质;(2)SSP的化学成分、结构性质等会受到生产工艺及使用环境的影响,进而影响其化学活性。通过降低SSP粒径、添加碱性激发剂或复合改性可以提高其胶凝活性及水化速率;(3)SSP作为土壤改良剂可以显著改善膨胀性黏土的性能,包括胀缩性和力学特性;(4)对于SSP与黏土之间的相互作用机制及复合激发剂的应用效果研究还相对不足,需要进一步探索;(5)未来应考虑不同因素耦合下的化学-矿物成分及土体微观结构演变规律,从宏微观角度建立土体在水-化-力作用下的力学特性。通过深入开展SSP改良土的微观机理和工程特性研究,可提高其工程应用价值,为固废资源的再循环利用和环境保护提供重要思路。

High-energy-density gelled fuels with high stability and shear thinning performance

Gelled fuels are the very promising propellants for new-generation rocket and ramjet propulsion.Here we report a new type of low-molecular mass organic gellant(Z),and prepared four kinds of stable gelled fuels based on HD-01,HD-03,RP-3 and QC liquid fuels,with the critical gellant concentration less than 1%(mass).The characterizations show that the gellant can form 3D network structure,via hydrogen bonding,π-πstacking and van der Waals forces,to fix fuel molecules during the formation of gelled fuels.So,the gelled fuels show high stability,with the remaining gel mass of 0.25%(mass)Z/HD-01 more than 90%even at high centrifugal speed of 7500 r·min^(-1),but the rheological property test shows that all gelled fuels have obvious shear thinning property,which benefits its storage in gelled state while supply in liquid state.The gelation of liquid fuels by gellant Z can increase the volumetric net heat of combustion(for HD-01,it increases from 39.58 MJ·L^(-1) to 40.76 MJ·L^(-1) with 1%(mass)Z),and liquefied gelled fuels show the comparable ignition delay time with the pristine liquid fuels.So,the gelled fuels made by gellant Z have better stability,shear thinning and combustion performances,which have great potential for the practical application.