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Static mixers are widely used in various industrial applications to intensify the laminar mixing of non-Newtonian fluids. Non-Newtonian fluids can be categorized into (1) time-independent, (2) time-dependent, and (3) viscoelastic fluids. Computational fluid dynamics studies on the laminar mixing of viscoelastic fluids are very limited due to the complexity in incorporating the multiple relaxation times and the associated stress tensor into the constitutive equations. This review paper provides recommendations for future research studies while summarizing the key research contributions in the field of non-Newtonian fluid mixing using static mixers. This review discusses the different experimental techniques employed such as electrical resistance tomography, magnetic resonance imaging, planar laser-induced fluorescence, and positron emission particle tracking. A comprehensive overview of the mixing fundamentals, fluid chaos, numerical characterization of fluid stretching, development of pressure drop correlations, and derivations of generalized Reynolds number is also provided in this review paper.

The purpose of this novel research was to intensify the mixing performance in a chaotic SMX static mixer at the lower primary flow rates of a yield pseudoplastic fluid. Since lower primary flow rates require less power consumption, this study enlightens the energy-efficient mixing in a chaotic SMX static mixer through the intensification of fluid deformation. Electrical resistance tomography (ERT) and computational fluid dynamics (CFD) techniques were utilized to achieve the objectives of this work. The CFD flow model was validated using the ERT tomograms, experimental pressure drop data, the secondary fluid concentration profile, and the mixing index. The species model was used to study the distribution of the secondary fluid concentration in the primary fluid. The effect of the secondary-to-primary velocity ratio on the degree of fluid deformation caused by the secondary fluid was investigated. The Newtonian secondary fluid (water) deformed the yield-pseudoplastic primary fluid more effectively than the non-Newtonian secondary fluid (0.5 wt% xanthan gum solution). Our results revealed that a more uniform radial dispersion of the secondary fluid in the primary fluid was attained through the intensification of fluid deformation at a higher secondary-to-primary velocity ratio.

Chauffeured car service (CCS) has developed rapidly in recent years. Although CCS brings convenience and effectiveness, it also triggers some new problems like vicious competition. This work studies the duopoly competition between CCS company and taxi company, in terms of different average cost and number of vehicles of two companies. To find the solutions like the pricing scheme to ease the vicious competition, Hotelling model is introduced. The Hotelling-type model is used to present passengers’ preferences to the companies. Besides, failing situation is taken into account in the Hotelling model to describe the situation where passenger’s demand is not satisfied in reality. This work theoretically analyzes the price scheme and equilibrium market segmentation based on the average cost and number of vehicles of each company. Furthermore, companies’ profits, passengers’ utility and social welfare in equilibrium are revealed based on the game theory. The study shows that both of companies can get optimal profits by setting effective price scheme. The company which has higher price, definitely gets less market share. In addition, moderate competition can lead to positive influence on social welfare.

Complex rheology of non-Newtonian fluids often leads to non-homogenous mixing due to the spatial viscosity gradients. The non-intrusive electrical resistance tomography (ERT) technique was employed to study the mixing of non-Newtonian fluids in a chaotic SMX static mixer. For the first time, the effect of the rheology of the yield-pseudoplastic fluids on the quality of distributive mixing was explored in this study. The non-Newtonian fluid used in this study was the xanthan gum solution, which is a yield-pseudoplastic fluid obeying the Herschel-Bulkley model and its rheological parameters change as the solution mass concentration increases. The tomography images were utilized to investigate the efficacy of the distributive mixing of two different types of the secondary streams (Newtonian and non-Newtonian) in the primary stream of xanthan gum solutions (0.5 wt%, 1.0 wt%, and 1.5 wt%). Experiments were conducted for three different primary flow rates ranging from 3.5 L/min to 12.5 L/min while keeping the center-line injection of secondary stream fixed at 100 mL/min for all experiments. Our results revealed that the Newtonian secondary stream favored effective axial mixing over the non-Newtonian secondary stream. However, interestingly, for both types of the secondary streams, a more effective radial mixing was observed as the xanthan gum mass concentration increased at low Reynolds numbers.

The oil sands process-affected water (OSPW), produced in large amounts during the process of the extraction of crude oil from oil sands, is toxic mainly due to the presence of naphthenic acids (NAs), among other constituents. Ozonation is an effective method for the removal of NAs. To provide information for better control of the process of NAs ozonation, models based on mass balance were developed in this study to predict the concentration profiles of commercial NAs, dissolved ozone and gaseous ozone during the process. It was found that the developed models successfully predicted the concentrations of commercial NAs and gaseous ozone. For the dissolved ozone concentration, the developed model can predict the equilibrium concentrations well. However, the actual ozone consumption was higher than that predicted by the model at the initial period of the ozonation process. This deviation was possibly resulted from the inapplicability of the gas-liquid equilibrium conditions at the initial high rate stage of the reaction. In addition, the Henry's law constant and the overall mass transfer coefficient for the given system were determined experimentally. Also investigated in this study was the effects of inlet gaseous ozone concentration into the reactor on the removal of NAs and on the concentration of dissolved ozone. As expected, the increase in inlet ozone concentration enhanced the removal of NAs and increased the concentration of dissolved ozone. This article is protected by copyright. All rights reserved

This paper’s purpose is to investigate the formation process of affect, the mechanisms by which it functions, and the dynamic characteristics of its influence on team performance. Toward this end, we present a computational experiment based on agent-based modeling. In particular, the modeling deeply penetrates internal psychological activities. Two computational experiments are conducted under different internal and external conditions for the team, yielding the following results. The process of affect formation is influenced by not only difficulty but also order of the task. Processing task from simple to difficult improves the formation of positive affect and facilitates team performance. While processing task from difficult to simple leads to the formation of negative affect and obstructs team performance. This research extends prior findings by examining the dynamic interplay of the determinants of affect over time and the study method presented herein are appropriate for other studies focusing on psychological effects on team, laying the foundations for new ideas for studying team building and team development.

It is an important task in network security management to use defensive strategy to mitigate security risk. We obtain the Pareto-optimal set of defensive strategy using multi-objective optimization algorithm (MOO) based on attack tree. However, decision maker (DM) may find it problematic to select an appropriate defensive strategy from the Pareto-optimal set, and visualization of the Pareto-optimal set is an effective method. In well-known spectral seriation of heatmap, there exist problem of mapping identical objective values of the Pareto-optimal set to different colors. And there still exist problem of weak flexibility and interactivity while the original spectral seriation of heatmap doesn't provide interface for DM. We improve the clarity by mapping identical objective values to the same color through assigning identical ranked values for identical objective values, and increase interactivity by allowing DM reorder objects and solutions or set interested solutions. Finally, the most suitable defensive strategy will be obtained from the improved heatmap easily. Application and advantages of the proposed approach are illustrated through a case study.

Numerous surveys suggest that consumers often conduct pre-purchase searches not only on the retailer-hosted websites but also on third-party review sites. To reveal the different effects of reviews from third-party sites on product sales by comparing with the retailer-hosted websites, especially for review sentiments, a log-linear regression model integrating much more information of reviews is built for this purpose. Consumer reviews on 108 digital cameras respectively from Chinese famous retailer-hosted website namely jd.com and third-party site namely zol.com.cn are collected. The empirical results suggest that third-party reviews have more significant impact on high-involvement product sales than retailer-hosted reviews. Review sentiments have more impact on sales than ratings and the volume of reviews. This finding highlights the importance of considering text content of third-party reviews in understanding online consumer information search behavior and the influence on retail strategies.

Cellulosic biomass, the most common organic compound of primary energy source on earth, is a network of interwoven biopolymers of plant cell walls. Degradation of cellulose is important for global carbon recycling. Moreover, biofuel, a renewable fuel whose energy can be derived from cellulosic biomass by enzymatic hydrolysis of cellulases. Among cellulases are endoglucases that act synergistically for subsequent hydrolytic reactions to break down the polymeric cellulose. However, in cellulolytic enzyme activity endoglucanase plays a prominent role in initiating and sustaining the hydrolytic process. Endoglucanase randomly cleaves the cellulose polymer into smaller sugar and oligomeric polysaccharides. Characterization and quantification of endoglucanase activity is important for industry and in the overall study of cellulose degradation. All assays including those for endoglucanase fall into two broad categories either qualitative or quantitative. Quantitative assays can tell if the enzyme is present, how much and its activity. Measurement can be done indirectly using a secondary colorimetric product like (1) molybdenum blue, (2) 3-amino-5-nitrosalicylic acid, (3) bicinchoninic acid (BCA), and (4) 2-cyanoacetamide or directly using an antibody in an ELISA. In this chapter, we discuss several common protocols for the measurement of endoglucanase activity.

The surface-directed phase separation phenomena of a model binary polymer blend quenched into the unstable region of its binary symmetric phase diagram was studied numerically using the nonlinear Cahn–Hilliard theory coupled with the Flory–Huggins–de-Gennes theory. Long range surface potential within a square geometry, where one side of the domain is exposed to a surface with preferential attraction to one component of a binary polymer blend under a temperature gradient in the x -direction, was incorporated in the model. No transition from complete wetting to partial wetting for all quench depths and/or long range surface potentials was observed. The structure factor analysis for the bulk presented an exponential growth rate at the early stage of phase separation, which slowed down at the intermediate stage with a slope of 0.33, which is in agreement with the Lifshitz–Slyozov power law. As the diffusion coefficient increased, the rate of phase separation increased accordingly in the bulk. This led to faster transition time from the early to intermediate stage within the bulk. In deeper quenches, a higher rate of phase separation was observed along with lower surface enrichment. Deeper quenches also led to the faster rupture of spinodal waves in the bulk. The process of surface enrichment, however, was continuous for all quench depths studied. The effect of different temperature gradient values on the surface enrichment rate was studied for the first time within a long range surface potential setting. No noticeable change in surface enrichment was observed for different temperature gradients.

The nonlinear Cahn–Hilliard theory and the Flory-Huggins-de-Gennes theory were used to study numerically the surface-directed phase separation phenomena of a model binary polymer blend quenched into the unstable region of its binary symmetric upper critical solution temperature phase diagram. Short-range surface potential within a square geometry, where one side of the binary polymer blend is exposed to a surface with preferential attraction to one component of the blend that is under a linear temperature gradient along the direction perpendicular to the surface, was integrated into the model. The structure factor analysis showed a faster exponential growth at the early stage of phase separation and a slower growth rate at the intermediate stage with a slope of 0.31 within the bulk, which is consistent with the Lifshitz–Slyozov growth law. The investigation of surface enrichment rate at the surface wall demonstrated faster growth rate at the early stage with the slope of 0.5. This growth rate became slower at the intermediate stage with a slope of 0.13 near the surface. The effect of various temperature gradient values on the surface enrichment rate with constant temperature T1* at the surface preferentially attracting one of the polymer components and different temperature T2* at the opposite surface, where T1*>T2*, was studied for the first time. The results showed that the thickness of the wetting layer increased with increasing temperature difference ΔT*, where ΔT*=T1*−T2*. The structure factor analysis of the surface potential h1 effect on the phase separation within the bulk close to the surface showed earlier transition time for higher values of h1. However, there was no difference observed for transition time within the bulk at distances farther away from the surface. As the surface potential increased, spinodal wave became more visible in the bulk and the transition time from complete wetting to partial wetting occurred at a later time on the surface.

Dyes are the main pollutants in the textile industry effluents. To provide solutions to the environmental problem, a model dye, methylene blue (MB), was removed from aqueous solution by ozonation in a continuous reactor. The effect of liquid circulation on MB removal was investigated and an optimal circulation rate was found under given experimental conditions. Models based on film theory were developed to predict concentration profiles of MB, dissolved ozone and gaseous ozone for the continuous ozonation process. Validation of the models with experimental data indicates that the proposed models can successfully predict the concentration profiles. Evaluation of the models also reveals that the fast kinetic regime assumption was applicable for the mass balance model of MB, however, as evidenced by the presence of dissolved ozone shortly after the reaction started, the intermediate rate assumption better represented the variations of ozone concentration both in liquid phase and in gas phase.

In an attempt to maximize the amount of ozone reacting with lignin inside humid wheat straw, some of the ozone-reactive lignin degradation products were washed away before a second ozonolysis delignification stage. The total contact time for the two stages was kept the same as that for a one-stage process for comparison. A significant decrease in the Acid Insoluble Lignin (AIL) content of the straw resulted: from 13.04 wt. % (after a 30-min one-stage ozonolysis) to 9.34 wt. % (after a 30-min two-stage ozonolysis, separated by a washing step). This significant improvement was accompanied by an increase in released fermentable sugars from an enzymatic hydrolysis. The yield increased from 60% theoretical sugars to 80%. A further improvement in AIL (down to 7.36 wt. %) and released sugars (up to 90% theoretical) occurred when the moisture content (MC) of the straw entering the second stage was adjusted to the optimum value of the straw entering first stage (45 wt. %, predicted from an experimental design). The authors believe this is the first time results are published for the introduction of a two-stage process separated by a washing step.

As the new form of online reviews, supplemental reviews have attracted the attention of many scholars. Considering current studies do not take full consideration on the content of reviews, the study goes better maturely and thoroughly on all information in supplemental reviews. In detail, sentiments of supplemental reviews in terms of different features corresponding to product, service and logistics are quantitatively analyzed. Except for the sentiments of reviews, other important factors including the volume of supplemental reviews, price, and ratings are introduced into the designed log-linear regression model for estimation. To explore the impact of supplemental reviews on product sales, an empirical study is conducted. The selected product with high involvement is mobile phone covering 32 products. The related sales as well as initial reviews and supplemental reviews are crawled from tmall.com for experiments. The period of data is from July 5, 2018 to July 24, 2018. By regression analysis, the results show that the sentiments of product features in both initial reviews and supplemental reviews and the sentiments of logistics features in supplemental reviews have significant positive impact on product sales. The volume of supplemental reviews has a negative impact on product sales. Compared with initial reviews, the impact of sentiments of product features on sales in supplemental reviews is greater.

Cellulosic biomass, the most common organic compound of primary energy source on earth, is a network of interwoven biopolymers of plant cell walls. Degradation of cellulose is important for global carbon recycling. Moreover, biofuel, a renewable fuel whose energy can be derived from cellulosic biomass by enzymatic hydrolysis of cellulases. Among cellulases are endoglucases that act synergistically for subsequent hydrolytic reactions to break down the polymeric cellulose. However, in cellulolytic enzyme activity endoglucanase plays a prominent role in initiating and sustaining the hydrolytic process. Endoglucanase randomly cleaves the cellulose polymer into smaller sugar and oligomeric polysaccharides. Characterization and quantification of endoglucanase activity is important for industry and in the overall study of cellulose degradation. All assays including those for endoglucanase fall into two broad categories either qualitative or quantitative. Quantitative assays can tell if the enzyme is present, how much and its activity. Measurement can be done indirectly using a secondary colorimetric product like (1) molybdenum blue, (2) 3-amino-5-nitrosalicylic acid, (3) bicinchoninic acid (BCA), and (4) 2-cyanoacetamide or directly using an antibody in an ELISA. In this chapter, we discuss several common protocols for the measurement of endoglucanase activity.

The slant cone mixer with an intensifier bar is an advanced type of the powder mixer which is a combination of the tumbling and agitator blenders. In this study, the discrete element method (DEM) was employed to investigate the mixing of solid particles in a slant cone mixer. To achieve this goal, the effects of initial loading (side-side, top-bottom, and back-front), drum speed, fill level, and agitator speed on the mixing rate were explored. In addition, the effect of the rotational direction of the agitator in relation to the direction of the drum (co-rotating and counter-rotating) on the mixing performance of the slant cone mixer was studied. In order to provide a mathematical understanding of the mixing rate, Lacey index was utilized. DEM results were validated using experimental data obtained from both sampling and image techniques. DEM simulation results were in good agreement with the experimentally determined data, both qualitatively and quantitatively.

As the traditional networks cannot meet the growing bandwidth and flexibility requirements of industry users, the big data transmission from end devices to the cloud server is becoming the bottleneck to the development of industry Internet. Fiber-Wireless (FiWi) access network which combines the advantages of optical and wireless networks has caught a wide attention and become a promising solution. However, different protocols as well as resource scheduling mechanisms between optical and wireless subnetworks of FiWi access network pose a huge challenge to its seamless integration and resource optimization. Network virtualization, which allows several Virtual Networks (VNs) running independently on the common Substrate Network (SN) and provides customized services to end users, becomes an effective solution for the network ossification problem of industry FiWi access network. However, due to the diverse needs for node and link resources of industrial VNs, the residual resources of nodes and links in SN may easily become unbalanced during the Virtual Network Embedding (VNE), which impairs the resource utilization of SN. Considering the resource fragmentation problem in VNE approaches, an online VNE algorithm is proposed in this paper. Our work aims to improve the VN acceptance ratio and SN resource utilization through minimizing the resource occupied by VNs and reducing the resource fragmentation degree of SN.

Under the circumstances of open innovation, exploratory and exploitative learning are thought to be effective ways to improve team performance especially for team creativity. Team leaders on one hand have much more rights and resources to influence the process of team learning. On the other hand, they are prone to delegate their powers to encourage team members to get involved in team work thoroughly. By which way can the empowering leadership affect the team creativity? To clarify this point, the paper employs 266 questionnaires from 51 project teams to explore the influence path between empowering leadership and team creativity by taking exploratory and exploitative learning as the mediators. Empirical results show that exploratory learning including experiment and external communication and exploitative learning including team reflection and internal communication play the mediating roles between situational and psychological empowerment and team creativity. Comparing with two types of empowerment, the role of psychological empowerment is more important than situational empowerment for exploratory learning, whereas for exploitative learning situational empowerment is more important than psychological empowerment.

Naphthenic acids (NAs) are toxic constituents of oil sands process-affected water (OSPW) which is generated during the extraction of bitumen from oil sands. NAs consist mainly of carboxylic acids which are generally biorefractory. For the treatment of OSPW, ozonation is a very beneficial method. It can significantly reduce the concentration of NAs and it can also convert NAs from biorefractory to biodegradable. In this study, a factorial design (2(4)) was used for the ozonation of OSPW to study the influences of the operating parameters (ozone concentration, oxygen/ozone flow rate, pH, and mixing) on the removal of a model NAs in a semi-batch reactor. It was found that ozone concentration had the most significant effect on the NAs concentration compared to other parameters. An empirical model was developed to correlate the concentration of NAs with ozone concentration, oxygen/ozone flow rate, and pH. In addition, a theoretical analysis was conducted to gain the insight into the relationship between the removal of NAs and the operating parameters.

We report a corrugated structure to effectively extract the surface plasmon polaritons (SPP) and waveguiding modes in organic light-emitting diodes (OLEDs). This structure is formed by nano-imprint of blazed gratings. To study the optimum extraction condition in terms of grating pitches, we compare the light extraction efficiency of corrugated OLEDs with three kinds of pitches, showing a 42.00% external quantum efficiency (EQE) enhancement ratio with this internal structure. Due to the transfer of SPP and waveguiding modes into substrate mode, the EQE enhancement ratio can be further pushed to 103.02% by attaching a macrolens. The simulation verifies the experimental results and shows the extraction mechanism of the corrugated structure towards transverse electric (TE) and transverse magnetic (TM) waves. We foresee that this method is able to enhance the optical efficiency of devices for both mass-production OLED lighting and display in a cost-effective way.

Application of ozone technology to lignocellulosic biohydrogen production was explored with a barley straw. Ozone pretreatment effectively degraded the straw lignin and increased reducing sugar yield. A simultaneous enzyme hydrolysis and dark fermentation experiment was conducted using a mixed anaerobic consortium together with saccharification enzymes. Both untreated and ozonated samples produced hydrogen. Compared to the untreated group, hydrogen produced by the groups ozonated for 15, 30, 45 and 90 min increased 99%, 133%, 166% and 94%, respectively. Some inhibitory effect on hydrogen production was observed with the samples ozonated for 90 min, and the inhibition was on the fermentative microorganisms, not the saccharification enzymes. These results demonstrate that production of biohydrogen from barley straw, a lignocellulosic biomass, can be significantly enhanced by ozone pretreatment.

Ozonation was tested as a pretreatment method for enhanced biohydrogen production from wheat straw. Ozone pretreatment effectively degraded wheat straw lignin, and the delignification increased with increase in the applied ozone dose. Results of reducing sugar measurement showed that under our experimental conditions ozone pretreatment significantly increased reducing sugar yields. A simultaneous enzyme hydrolysis and dark fermentation experiment was then conducted using a mixed anaerobic consortium, and the results demonstrated that ozone pretreatment significantly increased biohydrogen production. Compared to the untreated one, hydrogen production in the samples ozonated for 15, 30, 45 and 90 min increased 107%, 134%, 158% and 138%, respectively. Slight inhibitory effect on the dark fermentation was observed with the sample ozonated for 90 min, and the inhibitory effect was due to prolonged ozonation. These results proved that enhancement of biohydrogen production from lignocellulosic biomass using ozone as a pretreatment method is technically feasible.