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An ultrasound-assisted magnetic solid-phase extraction procedure with the [C7MIM][PF6] ionic liquid-coated Fe3O4-grafted graphene nanocomposite as the magnetic adsorbent has been developed for the determination of five nitrobenzene compounds (NBs) in environmental water samples, in combination with high performance liquid chromatography-photodiode array detector (HPLC-PDA). Several significant factors that affect the extraction efficiency, such as the types of magnetic nanoparticle and ionic liquid, the volume of ionic liquid and the amount of magnetic nanoparticles, extraction time, ionic strength, and solution pH, were investigated. With the assistance of ultrasound, adsorbing nitrobenzene compounds by ionic liquid and self-aggregating ionic liquid onto the surface of the Fe3O4-grafted graphene proceeded synchronously, which made the extraction achieved the maximum within 20 min using only 144 μL [C7MIM][PF6] and 3 mg Fe3O4-grafted graphene. Under the optimized conditions, satisfactory linearities were obtained for all NBs with correlation coefficients larger than 0.9990. The mean recoveries at two spiked levels ranged from 80.35 to 102.77%. Attributed to the convenient magnetic separation, the Fe3O4-grafted graphene could be recycled many times. The proposed method was demonstrated to be feasible, simple, solvent-saving and easy to operate for the trace analysis of NBs in environmental water samples. [ABSTRACT FROM AUTHOR]

An ultrasound-assisted magnetic SPE procedure with an Fe3O4-grafted graphene nanocomposite as the magnetic adsorbent has been developed to determine seven polychlorinated biphenyls (PCBs; PCB28, PCB52, PCB101, PCB118, PCB138, PCB153, and PCB180) simultaneously in 200 mL environmental water samples, in combination with GC-MS/MS. Several factors related to magnetic SPE efficiencies, such as the superparamagnetic intensity and amount of adsorbent, extraction time, sample pH, and desorption conditions were investigated. With the assistance of ultrasound, the extraction achieved the maximum within only 20 s, attributed to the powerful adsorptive ability of the magnetic adsorbent toward the PCBs. Under the optimized conditions, an excellent linearity was observed in the range of 0.1-100 ng/L for PCB28, 0.2-100 ng/L for PCB52, and 0.5-100 ng/L for the other five PCBs with the correlation coefficients ranging from 0.9988 to 0.9996. The mean recoveries at spiked levels of 5.0 and 10.0 ng/L were 84.9-108.5%, the coefficients of variations were <6.5%. With convenient magnetic separation, the synthesized magnetic adsorbent could be recycled more than ten times. The proposed method was demonstrated to be feasible, simple, rapid, and easy to operate for the trace analysis of the PCBs in environmental water samples. [ABSTRACT FROM AUTHOR]

The evolution of the surface waves for vertical free-falling films with Reynolds number ranging from 440 to 5,100 was measured using multiple-point conductance sensors and a computer-based data acquisition system. The physical and mathematical models describing the free-falling turbulent wavy films with the free surface boundary are presented. The governing equations are solved numerically in the film waves based on the coordinate transformation of the measured time-dependent film thickness data. The results show that the evolution of the surface waves has a remarkably nonlinear nature. The hydrodynamics and velocity profiles at the wave front, the wave crest, and the wave back for the solitary waves indicate significant effects of the solitary surface waves with interior recirculation flow on heat and mass transfer enhancement. A correlation for an average heat transfer coefficient is proposed as a function of the Reynolds and Prandtl numbers based on the measurements. [ABSTRACT FROM AUTHOR]

• Three technical scenarios are proposed and the thermal performance is analyzed. • Organic Rankine cycle is employed to recover the waste heat of reboiler condensate. • Waste heat of CO 2 compressed processes is provided for MEA renewable energy. • Parameter sensitivity is conducted for realizing overall optimal performance. • Thermo-economics of scenario III is the best at the heat ratio of 0.4. Coal-fired power generation units using carbon capture and storage (CCS) can reduce CO 2 emissions significantly whereas CCS consumes large amounts of renewable energy, leading to an efficiency penalty. To decrease the steam extraction and promote energy utilization efficiency, this study employs organic Rankine cycle (ORC) to recover the waste heat of reboiler condensate and utilizes the waste heat in CO 2 compressed processes to provide energy for carbon capture system. Three technical scenarios are proposed: (1) Coal-fired carbon capture power generation system: the medium-pressure cylinder exhaust is throttled by an auxiliary turbine and exchanges heat with H6 heater to provide energy for a reboiler; (2) Coal-fired carbon capture power generation system using ORC to recover the residual heat of reboiler condensate; (3) Solar-aided coal-fired power generation system using ORC and CCS: waste heat in CO 2 compression processes is supplied for a reboiler and ORC recovers the residual heat of reboiler condensate. The energy balance and overall performance of different scenarios are investigated with EBSILON, and the parameter sensitivity of scenario III is conducted. Results reveal that all scenarios improve the thermal performance of the system, and the thermo-economics of scenario III is the best at the heat ratio of 0.4. [ABSTRACT FROM AUTHOR]

To understand the origin and evolutionary history, and the geographical and historical causes for the formation of the current distribution pattern of Lquidambar formosana Hance, we investigated the phylogeography by using chloroplasts DNA (cpDNA) non-coding sequences and species distribution models (SDM). Four cpDNA intergenic spacer regions were amplified and sequenced for 251 individuals from 25 populations covering most of its geographical range in China. A total of 20 haplotypes were recovered. The species had a high level of chloroplast genetic variation (Ht = 0.909 ± 0.0192) and a significant phylogeographical structure (genetic differentiation takes into account distances among haplotypes (Nst) = 0.730 > population differentiation that does not consider distances among haplotypes (Gst) = 0.645; p < 0.05), whereas the genetic variation within populations (Hs = 0.323 ± 0.0553) was low. The variation of haplotype mainly occurred among populations (genetic differentiation coefficient (Fst) = 0.73012). The low genetic diversity within populations may be attributed to the restricted gene flow (Nm = 0.18). The time of the most recent common ancestor for clade V mostly distributed in Southwestern China, Central China, Qinling and Dabieshan mountains was 10.30 Ma (95% Highest posterior density (HPD): 9.74–15.28) dating back to the middle Miocene, which revealed the genetic structure of L. formosana was of ancient origin. These results indicated that dramatic changes since the Miocene may have driven the ancestors of L. formosana to retreat from the high latitudes of the Northern Hemisphere to subtropical China in which the establishment and initial intensification of the Asian monsoon provided conditions for their ecological requirements. This scenario was confirmed by the fossil record. SDM results indicated there were no contraction–expansion dynamics, and there was a stable range since the last interglacial period (LIG, 130 kya). Compared with the population expansion detected by Fu's Fs value and the mismatch distribution, we speculated the expansion time may happen before the interglacial period. Evidence supporting L. formosana was the ancient origin and table range since the last interglacial period. [ABSTRACT FROM AUTHOR]

To offset the power losses caused by the large energy consumption of carbon capture systems in coal-fired power systems, integrating a solar energy system is regarded as a prospective choice. Two scenarios for integrating a solar energy system and carbon capture system for a representative double-reheat coal-fired power system are proposed in this study. Matrix models are established to examine the thermal performance of the coupled system, and a comprehensive investigation of the external fuel exergy contribution, parameter sensitivity, investment cost, and system optimisation is performed. Results reveal that both scenarios improve the thermal performance of the system. The thermoeconomic and exergy evaluation indicators in scenario I are less competitive than those in scenario II. Compared with scenario II, however, the economy of scenario I is superior, and the potential of investment and utilisation is more competitive. When optimizing scenario II, under the ratio of the heat from the solar system to that required by the reboiler of φ = 0.3, the coupled system presents better thermal performance and reasonable irreversible degree, and the selection of φ = 0.3 is conducive to investment and economic benefits. • Matrix models of thermodynamics and fuel exergy contribution are established. • Thermoeconomic indicators and irreversibility of two scenarios are examined. • Contributions of external fuel exergy and investment cost are investigated. • Effect of various sensitivity indicators on the thermal performance is revealed. • Possible scenario is proposed to save the investment cost of solar collection field. [ABSTRACT FROM AUTHOR]

The models describing the mass transfer and chemical reaction of flue-gas−slurry drops in the deacidification tower of waste incineration plants are established. The internal dynamics are simulated and the effects of flue-gas inlet velocity, stoichiometric ratio, drop size and water spray rate, on deacidification performance, are evaluated. Results show that simulated desulphurisation and dechlorination rates are 58.97% and 99.99% and the removal rate of HCl is greater than SO 2 . A high-temperature zone is found in the upper part of central axis, whereas low-temperature zones are observed at the right wall and bottom. Flow field is characterized with complex recirculation zones, wherein the recirculation zone emerged on the upper-right entrains a small part of drops towards the right wall. Approximately 60% of the total removal amount of SO 2 and 90% of HCl are absorbed in the upper part. Slurry drops completely evaporate in 5 s after entering the deacidification tower. The deacidification performance is improved with the increase in stoichiometric ratio and water spray rate, as well as the decrease in inlet gas velocity and drop size. Excellent deacidification performance is expected under flue-gas inlet velocity of 7.1 m/s, drop size of 50–70 μm, and water spray rate of 600 L/h. [ABSTRACT FROM AUTHOR]

Evaporation of a binary mixture droplet (BMD) is a common natural phenomenon and widely applied in many industrial fields. For the case of a sessile BMD being the only contact-line pinning throughout an entire evaporation, a theoretical model describing the evaporating dynamics is established when considering the comprehensive effect of evaporative cooling, the thermal Marangoni effect, the solutal Marangoni effect, the convection effect, and the Stefan flow. The dynamics of a binary ethanol–water droplet on a heated substrate is simulated using a cylindrical coordinate system. The reasons for Marangoni instability-driven flow (MIF) are discussed, and the influence of initial ethanol concentration and substrate heating temperature are examined. An evaporating BMD first forms a MIF at the contact line and quickly affects the whole droplet. Under the influence of the Marangoni instability, the BMD presents a complex internal flow structure with multiple-vortex and nonlinear temperature and ethanol concentration distributions. The positive feedback induced by vortices and the nonlinear distribution of concentration and temperature promotes the development of a MIF. At low initial ethanol concentrations, the MIF loses its driving force and turns into a stable counterclockwise single-vortex flow as ethanol evaporates completely. However, at high initial ethanol concentrations, the MIF exists in the entire evaporation. Increasing ethanol concentration and substrate heating temperature can delay the appearance of the MIF; ethanol concentration affects the MIF duration time, and heating temperature alters the MIF intensity. To enhance flow intensity and mass transfer of BMDs, the temperature difference should first be increased, followed by increased ethanol concentration. [ABSTRACT FROM AUTHOR]

We report a study of the thermocapillary migration of droplets under a radial thermal gradient and in a wettability-confined track. A three-dimensional mathematical model is established based on the lubrication approximation. By considering the contact-line dynamics, a method for determining the velocity of the contact line in different directions is proposed for a three-dimensional droplet. Numerical simulations are performed to investigate the variations in the droplet profile, contact angle, and contact line. Three substrate-wettability cases are considered: uniform, temperature-dependent, and track-dependent wettability. The results show that when the substrate wettability is uniform, the droplet height initially decreases rapidly, and its center becomes concave and then gradually evolves into a ring-like morphology. Reducing the temperature sensitivity of the liquid–gas interfacial tension or increasing the temperature sensitivity of the liquid–solid interfacial tension decreases the equilibrium contact angle and accelerates thermocapillary migration. When a droplet spreads in a wettability-confined track, a wave-like peak is formed on each side of the droplet along the track direction until it finally separates into two distinct parts. As the track width is decreased, the time taken for a droplet to split into two smaller droplets advances, and the separation time presents a linear relationship with the track width. [ABSTRACT FROM AUTHOR]

Hydrothermal carbonization (HTC) is a promising thermochemical method used to upgrade herbaceous biomass for high-grade fuel. However, the technique yields large amounts of organic process wastewater (PW), which must be properly disposed or reused. In this work, PW was used as water source to prepare HTC feedstock. The evolution of the chemical structure and formation mechanism of hydrochar over the course of four PW recycles were demonstrated by experimental determination of the chemical compositions, equilibrium moisture contents, carbon structures, functional groups, and micro morphologies of the biomass (cornstalk in this study) and resulting hydrochars. The chemical reaction pathways induced during the HTC of biomass was established on the basis of the evolution of the chemical characteristics of the hydrochars and organic components of PW. The results showed significant improvements in the fuel quality of hydrochar as the number of PW recycles increased. The higher heating value, mass yield, and energy recovery efficiency of the hydrochars increased to 23.31 MJ/kg, 62.16%, and 86.24%, respectively, after four PW recycles because PW recycling facilitates the conversion of biomass into a hydrochar matrix with a high carbonization degree and polymerization of intermediates into microspheres. As the number of PW recycles increased, the relative content of furan compounds in the aqueous product decreased and the content of aromatic compounds increased. Further analysis of the aqueous products revealed the polymerization of furfural and 5-hydroxymethylfurfural into aromatic compounds and inhibition of the direct polymerization of aldehydes into aromatic compounds. The results of this work provide a theoretical basis for studying the chemical reaction and evolution mechanism of herbaceous biomass during HTC with recycled PW. Image 1 • PW was recycled to reduce its discharge and the water consumption for HTC. • More microspheres were produced due to polymerization of organic intermediates. • The microspheres have higher reactive oxygen functional groups than the matrix. • About 10% of dissolved organics in PW polymerized again and formed solid particles. • The polymerization of aldehydes into aromatics was inhibited when PW was recycled. [ABSTRACT FROM AUTHOR]

• Artemisia argyi essential oil was visualized by TLC-direct bioautography. • Rapid identification of bioactive compounds by 2D GC × GC-TOFMS. • In vitro antibacterial activity of six compounds were determined. • A rapid and efficient method for determination of antibacterial substances was established. One of the primary components that contribute to Artemisia argyi 's effectiveness is essential oil, which has an exceptional antibacterial effect that has been well documented. The actual cause of its antibacterial activity and associated mechanism, however, are still not completely understood. For the first time, comprehensive two-dimensional gas chromatography coupled with time-of-flight mass spectrometry (2D GC × GC-TOFMS) and thin-layer chromatography-direct bioautography (TLC-DB) were employed to investigate its antibacterial components. The antibacterial properties of A. argyi essential oil were investigated, and the antibacterial activity of six compounds was evaluated, using Staphylococcus aureus (S. aureus) and Escherichia coli (E. coil) as test microorganisms. TLC-direct bioautography was used to screen two bioactive clusters. Following 2D GC × GC-TOFMS identification of bioactive clusters, six compounds were evaluated for in vitro antibacterial activity verification. All the components tested displayed antibacterial action. Results showed that α -terpineol and eugenol had high potent antibacterial activity (MIC＜0.62 mg/mL, IC 50 ＜2.00 mg/mL). For complex essential oils from traditional Chinese medicine, this method is efficient for quick screening and identifying antibacterial compounds. [ABSTRACT FROM AUTHOR]

Transition to turbulence in a magnetohydrodynamic channel flow is studied numerically under a uniform and constant streamwise magnetic field. The laminar–turbulence transition can be triggered with transient growth and subsequent breakdown of linear optimal perturbations in different forms: streamwise mode, a single oblique mode and a pair of symmetric oblique modes. The nonlinear evolution of optimal modes is analyzed via a series of direct numerical simulations at a single subcritical Reynolds number R e = 5000 and different Hartmann numbers H a ranged from 10 to 70. It is found that, the superposition of symmetric oblique modes can trigger the transition most efficiently even with a lower perturbation energy level. The streamwise mode is less efficient and transition can be observed only after adding three dimensional random noise at the moment of strongest energy amplification. The magnetic damping effect is significant at high Hartmann number and no transition is found under a sufficiently strong magnetic field with H a larger than approximately 70. This critical value can be predicted straightforwardly from the linear relationship of friction coefficient of channel flow and magnetic interaction parameter. [ABSTRACT FROM AUTHOR]

To explore the high thermal performance of the gas-fired decarburization power generation system with oxygen-enriched combustion (GDPGS-OC), the thermal performance of two GDPGS-OC operation schemes is examined. Based on the optimal operation scheme, a solar-assisted gas-fired decarburization power generation system with oxygen-enriched combustion (SGDPGS-OC) is proposed. The system uses the main condensed water to recover the waste heat of the CO 2 compression and storage system and introduces solar energy as an auxiliary heat source to heat part of the high-pressure circulating water. An energy, exergy, economic and environmental (4 E) evaluation of the SGDPGS-OC is performed, and the sensitivity analysis is conducted for key parameters on the thermal performance. The results show that the thermal performance, economy, and environmental protection of SGDPGS-OC are better than those of conventional GDPGS-OC. Raising the gas turbine load, direct normal irradiance, and flue gas recirculation temperature increases the net power generation efficiency and the exergy efficiency of the system and components. Compared with the gas turbine combined cycle, the global warming potential of the GDPGS-OC and the SGDPGS-OC is reduced by 98.45% and 98.48%, respectively, and the latter has a more obvious advantage of CO 2 emission reduction. • A novel gas-fired decarburization power generation system is proposed. • An energy, exergy, economic and environmental evaluation of the system is analyzed. • The inlet gas mass invariant mode has a high thermal performance. • Sensitivity analysis is conducted for key parameters on the thermal performance. • The proposed system could be a feasible strategy to realize clean energy production. [ABSTRACT FROM AUTHOR]

A comprehensive two-dimensional (2D) countercurrent chromatography (CCC) × gas chromatography (GC) was investigated for characterization of chemical constituents of Artemisia argyi essential oil, and orthogonality for the 2D chromatographic system was evaluated. A solvent system composed of n -hexane/acetonitrile/methanol (2:2:1, v/v/v) was selected for first dimensional separation of Artemisia argyi essential oil. Then all CCC fractions were analyzed by GC, which provided a wealth of information regarding the composition of the essential oil. Visualization of chemical compositions obtained from the comprehensive 2D CCC × GC separation was achieved by creation of a 2D contour plot map. Total peak capacity was evaluated and approximately 1392 peaks were obtained through a comprehensive 2D CCC × GC separation. A high spatial coverage and a low linear correlation coefficient were achieved. Meanwhile, all compounds were identified by GC-MS. The obtained 2D contour plot could be divided into six zones to show the characteristic chemical compositions. Six zones could be divided into different component groups, including monoterpenes, sesquiterpenes, monoterpene alcohols, phenols, aldehydes, ketones and esters, which could be used to identify compounds that have not been reported, and to predict the structure of unknown compounds in Artemisia argyi essential oil and comprehensively characterize fingerprint peak. [Display omitted] • Comprehensive 2D CCC × GC chromatographic analysis of Artemisia argyi essential oil. • Orthogonality metric was evaluated by convex hull and linear correlation coefficient. • Development of a 2D contour map for a complete and informative assessment of sample. • Separation and characterization of new constituents in Artemisia argyi essential oil. • Zonal substance classification for comprehensive identification of fingerprint peaks. [ABSTRACT FROM AUTHOR]

Huge amounts of highly concentrated organic wastewater and sludge, which are main environmental pollutants that are highly difficult and costly to dispose of, are generated along with rapid industrialization and urbanization. Petroleum coke slurry (PCS) is an established liquid fuel that can be used as a substitute to oil and as a gasification material. However, the poor storage stability of PCS significantly constrains its applications. In this study, highly concentrated organic wastewater, sludge, and petroleum coke were mixed to prepare a new PCS with high storage stability. During sealed storage, biogas bubbles were produced and diffused in the prepared PCS because organic matter in wastewater was consumed by microorganisms in the sludge. Biogas bubbles bonded with petroleum coke particles and formed gas–solid combos. The lifting and steric hindrance effects of biogas effectively prevented petroleum coke particles from settling and coagulating, thus enhancing PCS storage stability and extending the application range of PCS. Based on the mathematical model and the stability results, the sludge significantly increased the spatial structure strength of PCS, and the fermentation biogas diffused in the slurry further increased structure strength and enhanced slurry stability. [ABSTRACT FROM AUTHOR]

Compared to nanofluids with spherical particles, nanofluids with anisotropic particles possess higher thermal conductivity and present a better enhancement option in heat transfer applications. The viscosity variation of such nanofluids becomes of great importance in evaluating their pumping power in thermal systems. This paper presents a comprehensive review of the experimental and theoretical studies on the viscosity of nanofluids with anisotropic particles. The internal mechanisms of viscosity evolution are investigated considering three aspects: particle clustering, particle interactions, and Brownian motion. In experimental studies, important factors including classification and synthetic methods for particle preparation, base fluid, particle loading, particle shape and size, temperature, p H, shear stress and electric field are investigated in detail. Classical theoretical models and empirical relations of the effective viscosity of suspensions are discussed. Some crucial factors such as maximum particle packing fraction, fractal index and intrinsic viscosity models, are examined. A comparison of predictions and experimental results shows that the classical models underestimate suspension viscosity. A comprehensive combination of the modified Krieger-Dougherty (K-D) model with intrinsic viscosity relations for different aspect ratios is suggested for low particle loadings, and the modified Maron-Pierce model (M-D) is recommended for high particle loadings. Possible directions for future works are discussed.

An ultrasound-assisted magnetic SPE procedure with an Fe3 O4 -grafted graphene nanocomposite as the magnetic adsorbent has been developed to determine seven polychlorinated biphenyls (PCBs; PCB28, PCB52, PCB101, PCB118, PCB138, PCB153, and PCB180) simultaneously in 200 mL environmental water samples, in combination with GC-MS/MS. Several factors related to magnetic SPE efficiencies, such as the superparamagnetic intensity and amount of adsorbent, extraction time, sample pH, and desorption conditions were investigated. With the assistance of ultrasound, the extraction achieved the maximum within only 20 s, attributed to the powerful adsorptive ability of the magnetic adsorbent toward the PCBs. Under the optimized conditions, an excellent linearity was observed in the range of 0.1-100 ng/L for PCB28, 0.2-100 ng/L for PCB52, and 0.5-100 ng/L for the other five PCBs with the correlation coefficients ranging from 0.9988 to 0.9996. The mean recoveries at spiked levels of 5.0 and 10.0 ng/L were 84.9-108.5%, the coefficients of variations were <6.5%. With convenient magnetic separation, the synthesized magnetic adsorbent could be recycled more than ten times. The proposed method was demonstrated to be feasible, simple, rapid, and easy to operate for the trace analysis of the PCBs in environmental water samples., (© 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The mouse is a popular and versatile model for the study of scrapie and other transmissible spongiform encephalopathies. In this chapter, information is given for preparation of infectious material for inoculation and a method of clinical scoring that yields accurate and reproducible quantification of the scrapie incubation period. With the help of histopathological and immunopathological techniques, we can detect brain pathological changes in scrapie-infected animals at the cellular and molecular level. We will also describe the histological and immunocytochemistry methods we use for scrapie research, outline step-by-step procedures, discuss tissue preparation, fixation, and processing of specimens, and provide special hints to achieve successful staining. We also include our results of PrPSc and GFAP immunostaining in scrapie research. In conclusion, immunopathological staining is an important and useful tool in the research of scrapie pathology.