Rheological characteristics of coal tar and petroleum pitches with and without additives

An extensive study of rheological characteristics of coal tar and petroleum pitches with and without additives, namely, petroleum coke, natural graphite and carbon black has been made. It is found that all pitches, pure or mixed with a carbon additive are not Newtonian as reported in the literature, but behave Theologically as Bingham plastics with certain yield stress and plastic viscosity at all temperatures of measurement between 85–180°C. The yield stress and plastic viscosity both decrease with increase in temperature of the pitch. A pure petroleum pitch having the same softening point as that of a coal tar pitch is found to have a lower viscosity compared to that of the latter at all temperatures of measurement. This suggests that the criterion of softening point as a measure of suitability of a coal tar pitch binder in the manufacture of artificial carbon is not sufficient for petroleum pitches. Addition of ten parts of carbon black by weight of pitch results in a considerable decrease in viscosity change with temperature of the coal tar pitch compared to almost insignificant change in the case of the petroleum pitch of the same softening point. However, the addition of petroleum coke or natural graphite makes the pitch more viscous but does not change the temperature dependence of viscosity of either of the two types of pitches. The implications are discussed.     

Melt‐processable rubber: Chlorinated waste tire rubber‐filled polyvinyl chloride

Chlorinated ground rubber tire (Cl‐GRT) particles were used as filler in a plasticized polyvinylchloride (PVC) to develop a melt‐processable rubber composition. Physical properties of the Cl‐GRT‐filled PVC compound showed improvement compared to the nonchlorinated counterpart. Interaction between Cl‐GRT and PVC was examined on the basis of results of stress relaxation, dynamic mechanical thermal analysis, and solvent swelling studies. The Cl‐GRT could be loaded upto 40 parts per hundred parts of PVC, and the composition still retains the elastomeric characteristics. The Cl‐GRT‐filled composite was found to be reprocessable like the unfilled PVC compound. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 622–631, 2002; DOI 10.1002/app.10352     

Diels-alder adducts from safflower fatty acids: III. Acrylic and related acid dienophiles

The Diels-Alder adducts from alkali conjugated and elaidinized safflower fatty acids with acrylic, methacrylic, crotonic and cinnamic acids and their esters as dienophiles were obtained in 40–64% yields. Low yields of 16–18% were obtained when 10-undecenoic acid and its ester were used. Most of the adducts could be estimated quantitatively in the reaction products by column chromatography or gas liquid chromatography (GLC). For the estimation of the adducts from crotonic and 10-undecenoic acids a combination of column chromatography and GLC techniques was employed. Partitioning between hexane and 90% methanol, partial esterification with alkali washing, and splitting and fractional distillation under reduced pressure were methods used to obtain the adducts in 90–95% purity.     

高速公路施工区车辆强制换道耗时生存模型

为研究高速公路施工区车辆强制换道行为及其影响因素,采用生存分析中的半参数分析方法建立强制换道耗时的乘法风险率模型.通过无人机拍摄采集高速公路施工区的车辆换道耗时及其影响因素数据,最终确立换道耗时Cox比例风险模型,对换道耗时数据进行Cox回归建模分析.结果表明:近77%的换道车辆在10 s内完成换道;小型车和中型车经养护施工区的换道耗时未发现显著性差别;对于相同的换道耗时,平峰期的累积生存率明显低于高峰期和过渡时期,而高峰期的累积生存率最高.建立的强制换道耗时生存模型可有效的定量分析车型和交通时段对高速公路施工区车辆换道行为的影响,可为高速公路施工区交通管理控制及车辆换道行为建模及仿真奠定一定的理论基础.     

Near infrared light-induced disassembly of polymeric micelles based on methylene blue conjugated polyethylene glycol

Light-sensitive drug delivery systems are considered ideal for applications in the biomedical fields for their ability to release the payload in an on-demand spatiotemporal controlled manner through the manipulation of the light source. Among the broad radiation spectrum, near infrared (NIR) light is considered advantageous compared to UV and visible light, due to its inherently lower photodamage to normal tissues and deeper penetration to lesion areas. In this study, we report a successful synthesis of a polymer capable of undergoing partial degradation upon irradiation with NIR light by conjugating 10-N-carbamoyl linkage methylene blue (MB) moiety, a NIR photocleavable ligand, with polyethylene glycol (PEG). Through effective coupling of MB, a hydrophobic moiety, to the hydrophilic PEG molecule, an amphiphilic polymer was synthesized, as demonstrated by a lowered surface tension (55 mN/m at 0.1% wt/vol). Subsequently, photo-induced reversal of surface activity associated with self-assembled structure disruption, was displayed by surface tension measurements, size distribution analysis, and burst release profile of paclitaxel (PTX) from polymeric micelles upon the exposure to NIR irradiation.     

Preparation and cell-materials interactions of plasma sprayed strontium-containing hydroxyapatite coating

The use of strontium-containing hydroxyapatite (Sr-HA) as a biomaterial has been reported recently. In vitro and in vivo studies have shown that Sr-HA promotes osteoblast response and stimulates new bone formation. In order to extend its usage to major load-bearing applications, such as artificial hip replacement, it has been proposed that the material could be used in the form of a coating on implant surfaces. This paper reports a preliminary study of biocompatibility of plasma sprayed Sr-HA coatings on a metallic substrate. Coatings of Sr-HA containing 10 mol% Sr²⁺ was produced on titanium alloy substrates. The coating exhibited good bonding with the substrate. The bioactivity of Sr-HA coating was evaluated in vitro by immersion in simulated body fluid (SBF). After immersion in SBF, Sr-HA coating exhibited great ability to induce apatite precipitation on its surface. The possible effects of cell-materials interactions of Sr-HA coating were examined by culturing osteoprecursor cells (OPC1) on coating surfaces. The effect of Sr-HA was also compared to a hydroxyapatite (HA) coating, which is widely used in orthopedics and dentistry. The results indicated that Sr-HA coating had good biocompatibility with human osteoblasts. OPC1 cells survived and proliferated well on the surface of coating. Sr-HA coating promoted OPC1 cells attachment, and more local contacts were produced on the surface. The presence of Sr stimulated OPC1 cell differentiation and ALP expression. No deleterious effect on ECM formation and mineralization was found with Sr-HA coating. The results indicated that Sr-HA coating had good mechanical properties and bioactivity in vitro.     

On the applicability of diploid genetic algorithms in dynamic environments

Diploid genetic algorithms (DGAs) promise robustness as against simple genetic algorithms which only work towards optimization. Moreover, these algorithms outperform others in dynamic environments. The work examines the theoretical aspect of the concept by examining the existing literature. The present work takes the example of dynamic TSP to compare greedy approach, genetic algorithms and DGAs. The work also implements a greedy genetic approach for the problem. In the experiments carried out, the three variants of dominance were implemented and 115 runs proved the point that none of them outperforms the other.     

Neutrosophic classifier: An extension of fuzzy classifer

Fuzzy classification has become of great interest because of its ability to utilize simple linguistically interpretable rules and has overcome the limitations of symbolic or crisp rule based classifiers. This paper introduces an extension to fuzzy classifier: a neutrosophic classifier, which would utilize neutrosophic logic for its working. Neutrosophic logic is a generalized logic that is capable of effectively handling indeterminacy, stochasticity acquisition errors that fuzzy logic cannot handle. The proposed neutrosophic classifier employs neutrosophic logic for its working and is an extension of commonly used fuzzy classifier. It is compared with the commonly used fuzzy classifiers on the following parameters: nature of membership functions, number of rules and indeterminacy in the results generated. It is proved in the paper that extended fuzzy classifier: neutrosophic classifier; optimizes the said parameters in comparison to the fuzzy counterpart. Finally the paper is concluded with justifying that neutrosophic logic though in its nascent stage still holds the potential to be experimented for further exploration in different domains.     

Multi-objective reactive power market clearing in competitive electricity market using HFMOEA

This paper presents an application of a hybrid fuzzy multi-objective evolutionary algorithm (HFMOEA) for solving a highly constraint, mixed integer type, complex multi-objective reactive power market clearing (RPMC) problem for the competitive electricity market environment. In HFMOEA based multi-objective optimization approach, based on the output of a fuzzy logic controller crossover and mutation probabilities are varied dynamically. It enhances stochastic search capabilities of HFMOEA. In multi-objective RPMC optimization framework, two objective functions namely the total payment function (TPF) for reactive power support from generators and synchronous condensers and the total real transmission loss (TRTL) are minimized simultaneously for clearing the reactive power market. The proposed HFMOEA based multi-objective RPMC scheme is tested on a standard IEEE 24 bus reliability test system and its performance is compared with five other multi-objective evolutionary techniques such as MOPBIL, NSGA-II, UPS-EMOA and SPEA-2 and a new extended form of NSGA (ENSGA-II). Applying all these six evolutionary techniques, a detailed statistical analysis using T-test and boxplots is carried out on three performance metrics (spacing, spread and hypervolume) data for RPMC problem. The obtained simulation results confirm the overall superiority of HFMOEA to generate better Pareto-optimal solutions with higher convergence rate as compared to above mentioned algorithms. Further, TPF and TRTL values corresponding to the best compromise solutions are obtained using said multi-objective evolutionary techniques. These values are compared with one another to take better market clearing decisions in competitive electricity environment.