Designing a sustainable closed-loop supply chain network based on triple bottom line approach: A comparison of metaheuristics hybridization techniques

Recently, there is a growing concern about the environmental and social footprint of business operations. While most of the papers in the field of supply chain network design focus on economic performance, recently, some studies have considered environmental dimensions.     

EDTA-柠檬酸法合成的SrCo0.8Fe0.2O3-δ钙钛矿的结构及制氧性能研究

采用EDTA-柠檬酸联合络合法合成了钙钛矿型金属氧化物SrCo_0.8Fe_0.2O_3-δ(SCF182)粉体。通过XRD和ESEM研究了前驱体溶液不同的pH值对合成的SCF182粉体的晶体结构和微观形貌的影响。并采用固定床实验研究前驱体溶液pH值对SCF182的氧吸附/脱附性能的影响。结果表明,pH值对SCF182晶胞结构和参数影响不大,但影响SCF182的晶粒粒径和微观形貌,当pH值为8的弱碱性条件下时,能够合成蓬松多孔网状纳米结构的钙钛矿粉体。固定床实验显示,前驱体溶液的pH值影响合成的粉体SCF182的氧吸附速率;且SCF182的氧脱附性能随pH值的增大先升高后降低,pH值为8时氧脱附量达到峰值为42.2 mg/g。     

Effects of biopolymer ratio and heat treatment on the complex formation between whey protein isolate and soluble fraction of Persian gum

Proteins and polysaccharides are the two most important natural ingredients with unique functional properties. Their interactions can be considered as a route to produce new materials of various technological applications. In this study, the effect of pH (3–7) as well as the mixing ratio of whey protein isolate (WPI)/soluble part of Persian gum (PG) (1:3, 1:1, 3:1, 6:1, and 9:1% w/w WPI/PG) on the complex formation behavior of the two polymers were studied using spectrophotometric and dynamic light scattering techniques, soluble protein measurement, and microscopic observations. Investigating the curves of turbidity versus pH showed that pHc and pH_?1, which are associated with the formation of soluble and insoluble complexes, moved toward higher pH values by increasing WPI:PG ratio. Increased solubility was observed at pHc?>?pH?>?pH_?1 for all biopolymers mixtures. In addition, lowering the pH toward pH_?1 resulted in a decrease in the size of complexes, while further decrease of pH beyond this point led to larger particles. No significant difference was noticed between pH_c and pH_?1 of heated and unheated WPI/PG mixtures, although the turbidity of heated samples increased due to the formation of larger aggregates.     

Boranil dyes bearing tetraphenylethene: Synthesis,AIE/AIEE effect properties,pH sensitive properties and application in live cell imaging

A serial of novel fluorescent boranil dyes (7, 8, 9, 10) bearing tetraphenylethene were prepared through an efficient process. These dyes exhibited large stokes shifts (more than 5000?cm^?1) and moderate fluorescent quantum yield from 0.22–0.53. Dye 9 exhibited AIE/AIEE and exhibited weak fluorescence in pure MeCN or the MeCN/water mixture with a water fraction below 80%, in which a significant AIEE effect was observed in the mixture with 80% of water fraction and a sharp increasement in fluorescence intensity was also observed. And dye 8 and 10 showed moderate solvatochromism with the solvent changed from toluene to DMSO, and they displayed sensitivities to pH change in MeCN/water solution. Interestingly, dyes 8 and 10 obtained by column chromatography and slow solvent evaporation showed different X-ray diffraction properties. Moreover, compound 8 and 10 could be applied to cell imaging.     

Separating nanoparticles by surface charge group using pH-controlled passivated gel electrophoresis

Because ionically stabilized colloids in aqueous dispersions have net surface charges that depend on pH, it is potentially possible to separate mixtures of nanospheres having identical radii, yet different types of stabilizing surface charge groups, efficiently using passivated gel electrophoresis (gel-EP). To demonstrate this, we separate a binary dispersion of polystyrene nanospheres that have nearly identical radii and surface group densities, yet different types of anionic stabilizing surface charge groups: sulfate and carboxylate. We achieve an efficient separation by adjusting the pH of the running buffer to lie between the pK_a values of these charge groups, resulting in significantly different protonation and, consequently, different electrophoretic propagation velocities of the nanospheres. The measured steady-state propagation velocities of both types of anionic nanoparticles as a function of pH can be fit well by an equilibrium model of pH-dependent protonation of anionic surface charge groups. Thus, pH-controlled passivated gel-EP opens a route for separating similarly sized charged colloidal objects that are stabilized by a variety of different surface charge groups.     

RAFT made methacrylate copolymers for reversible pH‐responsive nanoparticles

In this study, we designed and investigated pH‐responsive nanoparticles based on different ratios of monomers with primary, secondary or tertiary amino groups. For this purpose, copolymers of methyl methacrylate (MMA) with different compositions of amino methacrylates (2‐(dimethylamino)ethyl methacrylate (DMAEMA), 2‐(tert‐butylamino)ethyl methacrylate (tBAEMA) and 2‐aminoethyl methacrylate hydrochloride (AEMA·HCI)) were synthesized using the reversible addition‐fragmentation chain transfer (RAFT) polymerization process. The controlled nature of the radical polymerization was demonstrated by kinetic studies. All copolymers show low dispersities (?_M < 1.2) with amino contents between 9 and 21 mol %. For the nanoparticle formation, nanoprecipitation with subsequent solvent evaporation was used. All suspensions were characterized by dynamic light scattering (DLS) and scanning electron microscopy (SEM). Different initial conditions of the formulations resulted in differently sized nanoparticles that have monomodal size distributions, relatively narrow polydispersity index (PDI) values and positive zeta potential values. The pH‐stability test results demonstrated that, depending on the structure and amount of the amino content, the obtained nanoparticles reveal a reversible pH‐response, such as dissolution at acidic pH values. The ability of the nanoparticles to encapsulate guest molecules was confirmed by pyrene fluorescence studies. The cytotoxicity assay results showed that the nanoparticles did not have any significant cytotoxic effect. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 2711–2721     

pH and temperature-responsive wormlike micelles formed by single amine oxide surfactant

In this paper, a novel type of pH- and temperature-responsive smart wormlike micelles based on (Z)-N,N-dimethyl-3-(octadec-9-enamido) propan-1-amine oxide (OAPAO) synthesized was studied. The structure of OAPAO was characterized by ¹H NMR and FTIR. The micellization and aggregation properties of the OAPAO surfactant in aqueous solution at different pH values were studied using equilibrium surface tension. The OAPAO solution exhibited pH-regulated surface activity at the air–water interface by assessing relevant parameters such as cmc, γ_cmc, Г_max, and A_min at pH?=?2.10, 6.80, and 11.90. The viscosity and rheological measurements demonstrated the pH-sensitive flowing behavior and property, which was attributed to the interactions transition between the OAPAO head groups. Moreover, the system could be promptly switched between low viscous fluid and highly viscoelastic fluid by alternatively adjusting the pH between 2.05 and 6.82. Combining the distribution state of OAPAO, a mechanism for the different intermolecular forces at different pH regions was proposed. Furthermore, the OAPAO solution exhibited an evident temperature-responsiveness at pH?=?6.82 and 11.88 in a certain temperature range (25–65°C) resulting from the effect of temperature on the hydrophobic effect and the intermicellar branching junctions.     

地方本科院校化工卓越人才螺旋渐进培养模式的探索与实践——以德州学院化学工程与工艺专业为例

Combining the training requirements of chemical outstanding engineers, operating conditions and the demand of local chemical enterprises, we put forward the step-by-step guidance mode based on supervisor responsibility system. The guidance mode will improve innovation quality and engineering practice ability of students, and form the cultivating mode of local universities.