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Developing ultrasensitive and user-friendly methods for the detection glucose has attracted more and more attention. By virtue of high selectivity and sensitivity, enzyme-based glucose sensor plays a key role in point-of-care sensing technology for detecting glucose concentration. In this study, Amplex Red (AR), as both indicator and mediator, was investigated to detect glucose in presence of glucose oxidase (GOx) enzymes using colorimetric and electrochemical methods. Without using any advanced techniques and sophisticated nanomaterials, 1 μM glucose can be easily detected through simply detecting the solution color with a visual colorimetric method. On the other hand, the electrochemical method can provide much higher sensitivity for the detection of glucose, which achieves a linear range spanning from 20 nM to 3.56 μM with a limit of 7.3 nM (signal-to-noise ratio SNR = 3). It is also found that the presence of other sugars such as fructose, lactose, and maltose have very limited interference effects on the detection of glucose. More importantly, a bare GC electrode was used in all these electrochemical measurements without any electrode surface modification, guaranteeing a simple and fast operation. The analytical platforms for the detection of glucose presented here not only provide simple, fast, and ultrasensitive methods, but also have the potential to advance the sensing technology in the application of other health diagnostic research areas. [ABSTRACT FROM AUTHOR]

This study aimed to use micro-FTIR with transmission mode to investigate cellulose crystallinity of developing cotton fibers. Compared with ATR-FTIR method, we found that micro-FTIR can obtain more information of cellulose inside of the developing cotton fibers, especially in high wavenumber of 2800–3000 cm−1 region. Combined with curve fitting method, a new IR crystallinity index (CI) method named wax crystallinity index (WCI) was introduced to evaluate the cellulose crystallinity in the development of cotton fibers based on the peak and area ratios of 2900 cm−1/2850 cm−1 and 2900 cm−1/2920 cm−1. The obtained WCI values demonstrated an excellent coefficient of determination with X-ray diffraction (XRD) CI method with the value up to 0.99. This study suggested that micro-FTIR was an effective technique to qualitatively analyze the crystallinity in developing cotton fibers combined with curve fitting method. [ABSTRACT FROM AUTHOR]

[Display omitted] • Micro-FTIR spectroscopy provides a robust platform to classify transformation stages in tissue of ESCC. • 1D-CNN model offers a rapid identification and classification method for the analysis of 6352 raw spectral data. • The combination of micro-FTIR and 1D-CNN enables a high accuracy (over 93%) on predicting each stage. Among the most frequently diagnosed cancers in developing countries, esophageal squamous cell carcinoma (ESCC) ranks among the top six causes of death. It would be beneficial if a rapid, accurate, and automatic ESCC diagnostic method could be developed to reduce the workload of pathologists and improve the effectiveness of cancer treatments. Using micro-FTIR spectroscopy, this study classified the transformation stages of ESCC tissues. Based on 6,352 raw micro-FTIR spectra, a one-dimensional convolutional neural network (1D-CNN) model was constructed to classify-five stages. Based on the established model, more than 93% accuracy was achieved at each stage, and the accuracy of identifying proliferation, low grade neoplasia, and ESCC cancer groups was achieved 99% for the test dataset. In this proof-of-concept study, the developed method can be applied to other diseases in order to promote the use of FTIR spectroscopy in cancer pathology. [ABSTRACT FROM AUTHOR]

Abstract: In this essay, three novel nonlinear optical (NLO) azo-materials containing indole and sulfonyl based chromophores were studied in-depth by using Fourier transform (FT) IR, FT-Raman spectra and density functional theory (DFT). The scaled theoretical results were shown to be in good agreement with the experimental data. In addition, the computed 1H nuclear magnetic resonance (NMR) and UV–vis absorption wavelengths were also discussed compared with experimental data. The large β values calculated by the DFT methods showed that the studied molecules were good NLO materials, and the molecule which owned a larger substituent group on the indole chromophore moieties had a larger value. Furthermore, simultaneous infrared and Raman activity suggested that intramolecular charges might transfer through the conjugated framework from the electronic donor group to electronic acceptor group. The HOMO–LUMO gap analysis and molecular electrostatic potential (MEP) maps also supported this viewpoint. [Copyright &y& Elsevier]

Abstract: In this work, four-second order nonlinear optical (NLO) azobenzene-containing materials are studied in-depth by using vibrational spectra and density functional theory (DFT). The Fourier transform infrared (FT-IR) spectra and FT-Raman spectra are recorded in the range of 50–4000 and 100–3600cm−1, respectively. Meanwhile, the DFT computations are performed at B3LYP/6-31G (d, p) level to derive equilibrium geometry, vibrational wavenumbers and intensities, and first hyperpolarizability, and the scaled theoretical wavenumbers are also shown to be in good agreement with experimental data. The calculated results show that these four azobenzene-containing compounds are good materials and the compound with nitro substituent groups possesses a larger first molecular hyperpolarizability (β) value. Moreover, the simultaneous infrared and Raman activation of R1 group and Cing suggest that the charge transfer interaction might occur between the R1 group and phenyl ring, and the HOMO–LUMO gap analysis also supports this viewpoint. [Copyright &y& Elsevier]

Abstract: Air film cooling has been successfully used to cool gas turbine hot sections for the last half century. A promising technology is proposed to enhance air film cooling with water mist injection. Numerical simulations have shown that injecting a small amount of water droplets into the cooling air improves film-cooling performance significantly. However, previous studies were conducted at conditions of low Reynolds number, temperature, and pressure to allow comparisons with experimental data. As a continuous effort to develop a realistic mist film cooling scheme, this paper focuses on simulating mist film cooling under typical gas turbine operating conditions of high temperature and pressure. The mainstream flow is at 15atm with a temperature of 1561K. Both 2D and 3D cases are considered with different hole geometries on a flat surface, including a 2D slot, a simple round hole, a compound-angle hole, and fan-shaped holes. The results show that 10–20% mist (based on the coolant mass flow rate) achieves 5–10% cooling enhancement and provides an additional 30–68K adiabatic wall temperature reduction. Uniform droplets of 5–20μm are used. The droplet trajectories indicate the droplets tend to move away from the wall, which results in a lower cooling enhancement than under low pressure and temperature conditions. The commercial software Fluent is adopted in this study, and the standard k–ε model with enhanced wall treatment is adopted as the turbulence model. [Copyright &y& Elsevier]

The output and efficiency of gas turbines are reduced significantly during the summer. Gas turbine inlet air-cooling is considered a simple and effective method to increase the power output as well as thermal efficiency. Among various cooling schemes, fog cooling (a direct evaporative cooling) has gained increasing popularity due to its simplicity and low installation cost. During fog cooling, water is atomized to micro-scaled droplets (or mist) and introduced into the inlet airflow. The inlet air temperature is reduced through water evaporation. To investigate the mist transport in the entrance duct, numerical study is performed in this article. Different fundamental geometries are considered first, which include a straight tunnel, a diffuser, a contraction, and a 90° bend. These geometries are used to investigate the effect of acceleration, deceleration, and centrifugal force on mist transport and cooling effectiveness, respectively. Lastly, a duct representing a real application is used. The effects of droplet size, droplet distribution, and humidity on cooled air temperature distribution are examined. Analysis on droplet history (trajectory and size) is employed to interpret the mechanism of droplet dynamics under influence of acceleration, diffusion, and body forces. [ABSTRACT FROM AUTHOR]

Abstract: The flow field of a 2-D laminar confined impinging slot jet is investigated. Numerical results indicate that there exist two different solutions in some range of geometric and flow parameters. The two steady flow patterns are obtained under identical boundary conditions but only with different initial flow fields. Two different exit boundary conditions are investigated with two commercial software packages to eliminate artificial or computational effects. The different flow patterns are observed to significantly affect the heat transfer. A flow visualization experiment is carried out to verify the computational results and both flow patterns are observed. The bifurcation mechanism is interpreted and discussed. [Copyright &y& Elsevier]

One of the key points of modeling noncircular particles in the discrete element method is the contact detection of particles. In this study, a general contact detection algorithm of two-dimensional particles with analytic shape functions is provided. The contact detection of particles with strictly convex shape function, such as ellipses and superellipses, is solved by Newton–Raphson method, and a grid method is provided to deal with heart-shaped particles. The grid method can be generalized into a particle system, in which the shape function is not convex. The accuracy and stability of the algorithm are verified by a series of tests. For the collision of a pair of ellipses with an aspect ratio of α = a / b = 1000, the efficiency is not worse than the Newton–Raphson method. For random packing under gravity, no residual kinetic energy is observed, and the force that acts on the bottom is equal to the gravity, that is, the system reaches a mechanical equilibrium state. After equilibrium, the process of hopper discharge is also simulated. The present method is suitable for arbitrarily shaped particles with analytic shape functions in two-dimensional cases. In addition to superellipses, the method can also be applied to other particle systems as long as the shape functions are given. [ABSTRACT FROM AUTHOR]

In consideration of the increased activity of Pt-based catalysts for methanol oxidation in direct methanol fuel cells, it is necessary to apply an ideal support in the construction of Pt-based catalyst for methanol oxidation. In this study, Ag/g-C3N4 nanosheets (Ag/GCNN) nanocomposites with different Ag contents were synthesized and used as the progressive support to construct Pt/Ag/GCNN catalyst. As a nitrogen-rich polymeric semiconductor, GCNN is easily coordinated with various metals. The introduction of Ag nanoparticles can improve the electrical conductivity of the catalyst and cooperate with Pt for optimizing the performance of electrocatalytic oxidation of methanol. The electrochemical experiment results demonstrated that Pt/Ag/GCNN has higher electrocatalytic activity and stability for methanol oxidation than Pt/GC and Pt/GCNN. The mass activity of Pt/Ag/GCNN-0.6 (18.66 mA mgPt−1) is 7.07, 4.60 and 1.26 times that of Pt/GCNN (4.06 mA mgPt−1), Pt/Ag/GCNN-0.4 (4.06 mA mgPt−1) and Pt/Ag/GCNN-0.8 (14.76 mA mgPt−1) at the forward peak potential. The Jf/Jb ratio of Pt/Ag/GCNN-0.6 is 3.31, which is bigger than that of Pt/GCCN (2.62), Pt/Ag/GCNN-0.4 (2.69), and Pt/Ag/GCNN-0.8 (2.56). A suitable mechanism was proposed to explain that Ag/GCNN supported Pt catalyst can improve the CO toxicity resistance and electrocatalytic performance. Based on the coordination of GCNN, Ag was first modified to form a support, and then the remaining coordination sites were used to support Pt. It provided a new strategy for the design of catalysts for methanol electrooxidation. [ABSTRACT FROM AUTHOR]

From the canonical representation of the Marcum Q-function, a simple and highly accurate small argument approximation for the Marcum Q-function is first obtained. Utilizing this approximation, we derive the asymptotic error rate and outage probability expressions for multi-branch selection combining over generalized correlated Nakagami-m fading channels. These closed-form solutions can be used to provide rapid and accurate estimation of the error rates and outage probabilities in large signal-to-noise ratio regimes. It is shown that asymptotic error rates and outage probability over correlated Nakagami-m branches can be obtained by scaling the asymptotic error rates and outage probability over independent branches with a factor det^m(M), where det(M) is the determinant of matrix M whose elements are the square root of the corresponding elements in the branch power covariance coefficient matrix. [ABSTRACT FROM AUTHOR]

Sedimentation in a drain system has been recognized as one of the major causes of nuisance flooding produced by localized storms in Southeast Texas. The objective of the study is to assess the sediment load from runoff under different hydrological and road conditions to implement design guidance for a proper self-cleaning drain system. A diffusion wave model is developed to simulate runoff hydrodynamics on the roadway with curb inlets. An empirical sediment load equation is developed as a function of rainfall intensities, road conditions, and field sediment characteristics. The required flow velocity to erode the cohesive deposited sediment, and transport the deposited sediment incorporating the sediment from runoff in the drainpipe has been investigated to implement design guidance for a self-cleaning drain system. Regional hydrological conditions and field sediment characteristics are critical to design an effective drainage system for improving coastal resilience under severe weather conditions. [ABSTRACT FROM AUTHOR]

(Mn, Co) co-doped ZnO nanoparticles (NPs) were synthesized using the sol-gel method. Rietveld refined XRD patterns indicated that the NPs exhibited hexagonal wurtzite structures. Co and Mn ions were successfully introduced into the ZnO NPs at different concentrations. Moreover, Raman peak at 520 cm−1 was related to the defects induced by doping with Mn and Co ions. Fitting the O 1s XPS spectra of the NPs showed that more oxygen vacancies formed with increasing Co and Mn doping. Because there were more oxygen vacancies, photocatalytic dye degradation of rhodamine B enhanced at higher Co and Mn concentrations. Photoluminescence spectra showed that the NPs containing more Mn and Co had more single charged oxygen vacancies. The experimental and theoretical results showed that the exchange interactions between the Mn2+-Co2+ ions mediated by singly charged oxygen vacancies was responsible for room temperature ferromagnetism in the (Mn, Co) co-doped ZnO NPs. [Display omitted] • The magnetism of (Mn, Co) co-doped ZnO were estimated by DFT simulations. • The degradation of RhB for ZnO were enhanced by co-doping with Mn and Co. • The ferromagnetism of ZnO were improved by co-doping with Mn and Co. • Oxygen vacancies, Mn and Co ions were responsible for enhanced performance of ZnO. [ABSTRACT FROM AUTHOR]

• The high-crystalline g-C3N4 nanosheet was synthesized with a facile closed self-assembly strategy. • The synthesized high-crystalline g-C3N4 has a wider band gap and a greater specific surface area than bulk carbon nitride. • The photocatalytic activity of the high-crystalline g-C3N4 nanosheet was exhibited 6 times in hydrogen production than that of bulk g-C3N4. [Display omitted] High crystallinity and few layers of carbon nitride (g-C 3 N 4) can increase carrier migration rate and photocatalytic activity sites, which is beneficial to enhance the photocatalytic activity of carbon nitride. Herein, we synthesized high-crystalline g-C 3 N 4 nanosheets with a facile method of closed self-assembly strategy without adding any template and other auxiliary materials. XRD and HRTEM exhibited that high-crystalline g-C 3 N 4 was synthesized, the average thickness and specific surface area of the high-crystalline g-C 3 N 4 nanosheets were 4.8 nm and 95.10 m2g−1, respectively. Due to the efficient separation of photogenerated carriers and low charge-transfer resistance, high-crystalline g-C 3 N 4 nanosheets demonstrated much better photocatalytic activity (8116 μmol h−1 g−1) than that of bulk g-C 3 N 4 , exhibiting 6-folds of enhancement on hydrogen evolution. Beneficial from its good photocatalytic activity and convenient fabrication method, it is anticipated that high-crystalline g-C 3 N 4 nanosheets will find more applications in the renewable energy fields. [ABSTRACT FROM AUTHOR]

Abstract: Internal mist/steam blade cooling technology is considered for future high-temperature gas turbine systems that burn hydrogen or synthetic gases. This paper experimentally investigates the mist/steam heat transfer of three rows of circular jet impingement in a confined channel. Experiments were conducted with Reynolds numbers at 7500 and 15,000 and heat fluxes ranging from 3350 to 13,400W/m2. The results indicate that the wall temperature significantly decreased because of mist injection. The cooling enhancement region of the three-row jet impingement jets is more extensive than those employing one row of circular jets or a slot jet. The highest enhanced region spans about five jet diameters and becomes negligible downstream. The maximum local enhancement is up to 800% by injecting 3.5% of mist at low heat flux condition and 150% at high heat flux condition. The average cooling enhancement can achieve more than 100% within two jet-diameter distance from the stagnation line at Re =15,000 and m l/m s =1.5%. [Copyright &y& Elsevier]

Federal Regulation 40 CFR §63.670 requires flare operators to specify smokeless design capacity for flares with no visible emissions. Alternatively, 96.5% combustion efficiency (CE) or 98% destruction efficiency must be achieved with threshold limits of minimum combustion zone net heating value (NHVcz) ≥ 270 British thermal unit/standard cubic feet (BTU/scf) for steam-assisted and net heating value dilution parameter (NHVdil) ≥ 22 BTU/ft2 for air-assisted flares. There is still no guarantee for smokeless flaring (SLF) or CE >96.5%. Robust response surface models developed in this study expressed %CE and %Opacity as a function of operating variables for air- and steam-assisted flares. Opacity and CE test data from 1983 to 2016 were analyzed. General quadratic models with transforms of CE and Opacity showed R2 > 0.90, and bivariate sigmoid models for CE showed R2 > 0.87. Two-dimensional (2D) contours illustrate the trends of major operating parameters. Operational setpoints at the incipient smoke point (ISP) and SLF were determined by solving the models subject to NHVcz and NHVdil threshold limits specifying Opacity at 3% (ISP) and 2% (SLF). The predicted steam/air assists/makeup fuel, NHVcz (or NHVdil), and CE at ISP and SLF conditions are compared with the experimental 1984 Environmental Protection Agency (EPA) and 2010 Texas Commission on Environmental Quality flare study ISP test data. These setpoints would help flare operators to establish ISP or SLF conditions either by adding makeup fuel to vent gas with low heating value or by minimizing the assist without adding makeup fuel for steam- and air-assisted flares. [ABSTRACT FROM AUTHOR]

Doping with transition metal ion is an effective way to modulate the physical properties of ZnO. Here, structural, optical, gas-sensing and magnetic properties of (Mn, Ni) codoped ZnO nanorods prepared by hydrothermal method are investigated systematically. Reitveld refinement of X-ray diffraction patterns reveal (Mn, Ni) codoped ZnO nanorods with hexagonal crystal structure and a contraction in lattice parameters Mn and Ni-doping. Since transition metal ions doping could influence the microstructure and defect state, the (Mn, Ni) codoped ZnO nanorods show the higher sensitivity to ethanol gas and stronger room temperature saturation magnetization of nanorods. X-ray photoelectron spectra and UV–vis absorption spectra analysis reveal that oxygen vacancies related to defects in the nanorods increase with increasing Ni doping concentration, resulting in the increased carrier concentration. And the singly charged oxygen vacancies increase with Ni doping concentration derived from Gaussian fitting PL spectra result. This work demonstrates that the singly charged oxygen vacancies and surrounding transition metal ions forming bound magnetic polarons are accountable for the origin of ferromagnetism in (Mn, Ni) codoped ZnO nanorods. Unlabelled Image • Improved gas sensing and ferromagnetism properties are related to the concentration of oxygen vacancy. • The bandgap and carrier concentration increase with Ni concentration of (Mn, Ni) codoped ZnO nanorods. • Singly charged oxygen vacancies in the nanorods were analyzed by the PL spectra results. • V O + and surrounding Ni2+ and Mn2+ions are responsible for ferromagnetism in (Mn, Ni) codoped ZnO nanorods. [ABSTRACT FROM AUTHOR]

To evaluate the influence of transition metal substituents on the characteristics of CH3NH3PbI3/TiO2, we investigated the geometrical and electronic properties of transition metal-substituted CH3NH3PbI3/TiO2 by first-principles calculations. The results suggested that the substitution of Ti4+ at the five-fold coordinated (Ti5c) sites by transition metals is energetically favored. The substituted interface has enhanced visible light sensitivity and photoelectrocatalytic activity by reducing the transition energies. The transition metal substitution can effectively tune the band gap of the interface, which significantly improves the photo-reactivity. The substituted systems are expected to be more efficient in separating the photo-generated electrons-holes and active in the visible spectrum. [ABSTRACT FROM AUTHOR]

Partially overlapped plates submerged in water are of interest in some industrial applications such as in blade-adjustable hydraulic turbine runners, where the neighboring blades become closer and partially overlapped for certain operating conditions. To know the influence of partially overlapped structures on their dynamic behavior is of great importance to avoid resonances and therefore to extend their lifetime. In this paper, the dynamic behavior of two identical rectangular plates with a partially overlapped area in water has been studied experimentally and numerically. An experimental test rig has been constructed, which consists of two identical rectangular plates in a tank full of water. The distance and the overlapped area between the two plates can be changed to investigate their influence on the added mass, added damping and mode shapes. A finite element method model based on acoustic fluid-structure interaction was used to simulate the added mass effect of the plates from the surrounding water. A theoretical equation used to calculate the damping ratios of submerged structures has also been proposed. Theoretical, experimental and numerical results have been compared and analyzed. • The fluid-structure coupling vibration behavior of two partially overlapped identical plates submerged in water. • The interaction mechanics between two partially overlapped identical plates submerged in water. • Damping ratio variation mechanics of submerged structures. [ABSTRACT FROM AUTHOR]

To meet the diversified demands for the booming intelligent systems, a multifunctional pressure sensor with two basic capabilities of ultraviolet excited fluorescence and force-electricity response has been proposed, and named as fluorescent pressure sensor (FPS). Carbon quantum dots (CQDs) are being rapidly developed as an reasonable photoluminescence materials. However, the CQDs were utilized in the solid-state film along with serious aggregation-induced quenching (AIQ). Here, we developed a two-step method instead of the typical one-step method to overcome the AIQ of the CQDs in the representative piezoelectric polymer. The sponge-like poly (vinylidene) fluoride-hexafluoropropylene (PVDF-HFP) film with high porosity formed based on nonsolvent-induced phase separation was selected as the host matrix of the guest nitrogen-doped CQDs (N-CQDs). The impressive bright blue fluorescence with enhanced intensity derived from the N-CQDs is successfully implanted into the obtained N-CQDs/PVDF-HFP piezoelectric hybrid film, attributing to two key factors: (i) the sponge-like matrix supported uniform distribution of the N-CQDs and (ii) the hydrogen bonding between the N-CQDs and the matrix chains. Meanwhile, the hybrid film used in the FPS still keeps a sensitivity of 92.7 mV N−1, thanks to the β piezoelectric phase formation in the matrix. Since the hybrid film based FPS has multiple features, such as ultraviolet excited fluorescence, force-electricity response, self-powered capability and flexibility, it will show a great potential in the intelligent systems used as the multifunctional sensor and energy harvester. [Display omitted] • Fluorescent N-CQDs was uniformly implanted into PVDF-HFP by two-step process. • Obtained piezoelectric hybrid film owns new ability of ultraviolet excited fluorescence. • Enhanced blue fluorescence is from sponge-like matrix's support and hydrogen bonding. • Linear relation with R 2 = 0.999 and sensitivity = 92.7 mV N−1 are given for sensor. • Sensor shows tactile perception, UV perception, anti-counterfeiting and energy capture. [ABSTRACT FROM AUTHOR]

Composite thin films with BiFeO 3 (BFO), CoFeO 4 (CFO) and/or BaTiO 3 (BTO) layers as the components are fabricated via CSD method. XRD and Raman patterns show all the composite films can be indexed to perovskite and spinel structures. Except the interfaces between BTO and CFO layers, the other two-phase interfaces can be clearly observed. Interestingly, the BTO-CFO film has bigger polarization than BTO-BFO, especially the thickness of CFO layer is smaller than the BFO layer, implying the ferromagnetic layer has a significant impact on the ferroelectric properties of the composite films, which is too thin to be fully polarized. The variation of leakage currents show BTO-CFO film has the smallest value, corroborating the results of ferroelectric measurements. The leakage current is dominated by the space-charges-limited mechanisms according to the fitting results, and the oxygen vacancies in the BFO layers play an important role for the variations of E SCL and E TFL voltages. [ABSTRACT FROM AUTHOR]

BaTiO-CoFe O composite thin films with different thicknesses were fabricated via chemical solution deposition. Magnetic annealing and non-field annealing processes were applied in the sintering process, respectively. Variations of the structure and magnetic properties of the composite films induced by the magnetic annealing were investigated. It is found that the mean grain size and grain boundary are increased and decreased, respectively. For the magnetic-annealed films, the internal strain is reduced with the increase of film thickness. Magnetic measurements show that the M is also increased with the film thickness and the magnetic-annealed films have bigger M values than the non-field-annealed films. Based on the experimental results, it can be concluded that the effect of magnetic annealing on the structure and properties of the composite films is decreased with the increase of film thickness. [ABSTRACT FROM AUTHOR]

Emissions from flares constitute unburned hydrocarbons, carbon monoxide (CO), soot, and other partially burned and altered hydrocarbons along with carbon dioxide (CO2) and water. Soot or visible smoke is of particular concern for flare operators/regulatory agencies. The goal of the study is to develop a computational fluid dynamics (CFD) model capable of predicting flare combustion efficiency (CE) and soot emission. Since detailed combustion mechanisms are too complicated for (CFD) application, a 50-species reduced mechanism, LU 3.0.1, was developed. LU 3.0.1 is capable of handling C4hydrocarbons and soot precursor species (C2H2, C2H4, C6H6). The new reduced mechanism LU 3.0.1 was first validated against experimental performance indicators: laminar flame speed, adiabatic flame temperature, and ignition delay. Further, CFD simulations using LU 3.0.1 were run to predict soot emission and CE of air-assisted flare tests conducted in 2010 in Tulsa, Oklahoma, using ANSYS Fluent software. Results of non-premixed probability density function (PDF) model and eddy dissipation concept (EDC) model are discussed. It is also noteworthy that when used in conjunction with the EDC turbulence-chemistry model, LU 3.0.1 can reasonably predict volatile organic compound (VOC) emissions as well. Implications: A reduced combustion mechanism containing 50 C1–C4species and soot precursors has been developed and validated against experimental data. The combustion mechanism is then employed in the computational fluid dynamics (CFD) of modeling of soot emission and combustion efficiency (CE) of controlled flares for which experimental soot and CE data are available. The validated CFD modeling tools are useful for oil, gas, and chemical industries to comply with U.S. Environmental Protection Agency’s (EPA) mandate to achieve smokeless flaring with a high CE. [ABSTRACT FROM AUTHOR]

Zn 1- x Mn x O nanoparticles with different Mn concentration (0.01–0.1) were synthesized by co-precipitation technique. The structural, optical and magnetic properties of Zn 1- x Mn x O nanoparticles were investigated. The Zn 1- x Mn x O nanoparticles keep wurtzite structure without any impurity phase until the Mn concentration reaches 0.1. The magnetic measurements show ferromagnetism of Zn 1- x Mn x O nanoparticles is improved with increase of the Mn concentration ( x = 0.01–0.08). The optimal doping concentrations for enhancement in ferromagnetism of Zn 1- x Mn x O nanoparticles is 0.08. The reduction in ferromagnetism of Zn 0.9 Mn 0.1 O is caused by coexistence of the Mn 3+ and Mn 2+ ions, which can form antiferromagnetic interaction. Results of UV-vis absorption spectra indicate that the bandgap and carrier concentration increase gradually with increasing Mn concentration, which can be explained by Burstein-Moss shift. Singly charged oxygen vacancies in the Zn 1- x Mn x O were analyzed according to the visible photoluminescence spectra results. Experiment results reveal that the singly charged oxygen vacancies and surrounding Mn 2+ ions form bound magnetic polarons model, which is responsible for the origin of ferromagnetism in Mn-doped ZnO nanoparticles. [ABSTRACT FROM AUTHOR]

BaTiO 3 –CoFe 2 O 4 multilayer thin films with different thickness are deposited on Pt/Ti/SiO 2 /Si (100) substrates via CSD method. The magnetic annealing effect on the ferroelectric and dielectric properties of the multilayer thin films are investigated. It is found that both the ferroelectric and dielectric properties of the films are improved by the magnetic annealing. The changes of these two properties can be explained based on the variations of grain size, grain boundary, internal stress/strain as well as domain wall motion. A serial capacitor model is also used to analyze the influence of magnetic annealing on the dielectric properties. Leakage current densities are decreased after magnetic annealing and then fitted and explained with different leakage conduction mechanisms. Finally, comparing the ferroelectric and dielectric properties of the films with and without magnetic annealing, it can be concluded that the magnetic annealing effect is more significant on the thinner films. [ABSTRACT FROM AUTHOR]

A computational fluid dynamics (CFD) methodology for simulating the combustion process has been validated with experimental results. Three different types of experimental setups were used to validate the CFD model. These setups include an industrial-scale flare setups and two lab-scale flames. The CFD study also involved three different fuels: C3H6/CH4/Air/N2, C2H4/O2/Ar, and CH4/Air. In the first setup, flare efficiency data from the Texas Commission on Environmental Quality (TCEQ) 2010 field tests were used to validate the CFD model. In the second setup, a McKenna burner with flat flames was simulated. Temperature and mass fractions of important species were compared with the experimental data. Finally, results of an experimental study done at Sandia National Laboratories to generate a lifted jet flame were used for the purpose of validation. The reduced 50 species mechanism, LU 1.1, the realizable k-ϵ turbulence model, and the EDC turbulence–chemistry interaction model were used for this work. Flare efficiency, axial profiles of temperature, and mass fractions of various intermediate species obtained in the simulation were compared with experimental data and a good agreement between the profiles was clearly observed. In particular, the simulation match with the TCEQ 2010 flare tests has been significantly improved (within 5% of the data) compared to the results reported by Singh et al. in 2012. Validation of the speciated flat flame data supports the view that flares can be a primary source of formaldehyde emission.ImplicationsValidated computational fluid dynamics (CFD) models can be a useful tool to predict destruction and removal efficiency (DRE) and combustion efficiency (CE) under steam/air assist conditions in the face of many other flare operating variables such as fuel composition, exit jet velocity, and crosswind. Augmented with rigorous combustion chemistry, CFD is also a powerful tool to predict flare emissions such as formaldehyde. In fact, this study implicates flares emissions as a primary source of formaldehyde emissions. The rigorous CFD simulations, together with available controlled flare test data, can be fitted into simple response surface models for quick engineering use. [ABSTRACT FROM PUBLISHER]

Computational fluid dynamics (CFD) was applied to model industrial flares under low-Btu, low-flow rate conditions (stand-by mode). The modeled tests were conducted at the John Zink R&D facility in Tulsa, OK in September 2010, using propylene/Tulsa Natural Gas/nitrogen as vent gases under open-air conditions. This work focuses on CFD modeling using the EDC (Eddy Dissipation Concept) and PDF (Probability Density Function) models to predict the destruction and removal efficiency (DRE), combustion efficiency (CE), and speciated emissions with a reduced 50-species combustion mechanism. Generally, the EDC model underpredicts DRE/CE while the PDF model overpredicts DRE/CE, when compared with measurements. The sources of discrepancies and the challenges to the flare modeling in the stand-by mode are discussed. In view of the significant differences between the measured and modeled results, further investigations involving a better domain with a refined mesh, a different turbulence model, or a combination of EDC/PDF models are warranted. [ABSTRACT FROM AUTHOR]

Flaring is a combustion process designed to relieve pressures and safely dispose of vent gases from chemical and petrochemical plants. An industrial flaring activity typically involves various combustible waste gases and a large number of reactions and species. Because most of the detailed kinetic mechanisms for the speciation study of flaring events are too complicated to use in the computational fluid dynamics simulation of industrial-scale flares, several techniques for reduction of the detailed combustion mechanisms have been developed. In this paper, a new rigorous skeleton mechanism (RSM) based reduction technique, namely, the LU 2.0 algorithm, is proposed. It falls under the category of identification of redundancy. Other techniques in this category try to remove redundant species and reactions based on criteria such as sensitivity and quasi-steady-state analyses. These are highly dependent on the preanalysis of the mechanism and require species concentration sets for the conditions of interest. This algorithm tries to find out the skeleton mechanism with the lowest possible error. It works by rigorously testing all of the possible combinations of species sets. This RSM-based optimized mechanism was validated successfully against experimental data for various key performance indicators (laminar flame speeds, burner-stabilized flame, adiabatic flame temperature, and ignition delay) for methane, ethylene, and propylene flames. The efficacy of this algorithm was demonstrated by its improved predictability. [ABSTRACT FROM AUTHOR]

Abstract: Purpose: To improve the accuracy of blood loss estimation during extensive escharectomy and auto-microskin grafting on extremities in adult male major burn patients. Method: All adult male major burn patients admitted to our center who underwent extensive escharectomy and auto-microskin graft on extremities for more than 10%TBSA during the period 1 January 2008 to 31 December 2009 were involved in this study. The blood loss during the operation was estimated by the surgeons or calculated according to the changes in hemoglobin levels. Results: The average burn and escharectomy areas for the 64 burn patients included in the study were 74.16±16.96% and 30.27±15.63%TBSA respectively. The auto-microskin donor area was 3.81%TBSA. The volumes of intra-operative calculated and estimated blood losses and transfused blood during the operation were 0.47ml/cm2, 0.13ml/cm2 and 0.20ml/cm2 surgical area 77.29ml, 20.51ml and 32.83ml per 1%TBSA), respectively. Within two weeks after injury surgical blood loss appeared to be greater the later the operation was carried out. Within the first week after injury the mean proportional blood loss was increased with area excised. Conclusion: In this study the average calculated blood loss for the operation of extensive escharectomy and microskin graft in adult male major burn patient was 0.47ml/cm2 (77.29ml per 1% TBSA). This result will help us to predict expected blood loss more accurately. [Copyright &y& Elsevier]

This study aimed to determine whether mesenchymal stem cells (MSCs) derived from umbilical cord blood (UCB) would promote cutaneous wound healing. MSCs from human UCB were isolated and identified. The characteristics of the isolated MSCs' growth and proliferation were assayed in vitro. The MSCs labeled with 5-bromodeoxyuridine (BrdU) were applied on fresh cutaneous mice wounds. The healing rates were surveyed. The distribution and the differentiation into keratinocytes of the labeled MSCs in the wound tissue were checked by immunohistochemistry staining. The isolated MSCs could grow and proliferate well in vitro. The isolated MSCs from UCB could be labeled by 5-bromodeoxyuridine successfully. The MSCs derived from UCB could enhance the healing of mice skin defect wounds, and it was found that the implanted MSCs could differentiate into keratinocyte in the wound tissue. It was demonstrated that MSCs from UCB can be isolated and proliferated successfully. The local administration of MSCs derived from UCB improves skin defect wound healing in mice. [ABSTRACT FROM AUTHOR]

Abstract: Aim: This study aims to review the changes in management of inhalation injury and the associated reduction in mortality over the past 2 decades. Methods: The records of burn patients with inhalation injury hospitalised in our institute from 1986 to 2005 were retrospectively analysed. The incidence of inhalation injury and the associated mortality were analysed. Meanwhile, the relationship of inhalation injury with age, total burn area, tracheostomy intubation and mechanical ventilation were studied. Results: The incidence of inhalation injury was 8.01% in the total 10 608 hospitalised burn patients during the 20 years surveyed. Inhalation injury was always associated with large-sized burn and was more common in adults. The incidence of tracheostomy and mechanical ventilation increased from 39.46 and 30.28% in the period from 1986 to 1995 to 70.12 and 39.74% from 1996 to 2005, respectively. The overall mortality of inhalation-injured burn patients was 15.88% compared with 0.82% of the non-inhalation group. The mortality of the burn patients with inhalation injury dropped from 25.29% during the first 10 years to 11.71% during the second decade (p <0.01). Mortality secondary to inhalation injury as the lead cause decreased from 14.56 to 6.29% (p <0.01). Conclusion: The care of inhalation injury has made significant progress over the past 2 decades. The early diagnosis of inhalation injury, early airway control and pulmonary function assistance with mechanical ventilation contribute to the reduction of mortality. [Copyright &y& Elsevier]

To evaluate the antibacterial effect of multivalent silver ion carried by zirconium phosphate (ZP-Ag) both in vitro and in an experimental rat burn wound compared with that of sulfadiazine silver (SD-Ag). Firstly, the minimal inhibition concentration and the minimal bactericidal concentration of ZP-Ag to three different strains of bacteria ( Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli) were compared with those of SD-Ag in vitro. Following this dressings containing the same mass of ZP-Ag or SD-Ag were applied to wounds in a rat burn model and their antimicrobial activity assayed. The inflammatory response of the wounds managed with the two kinds of dressings was compared. Both the minimal inhibition concentration and minimal bactericidal concentration of ZP-Ag to S. aureus, P. aeruginosa, and E. coli were two to four times lower than those of SD-Ag. In vivo ZP-Ag had a more effective antibacterial action inhibiting the growth of the above three bacterial strains under burn scar, compared with dressings made from the same mass of SD-Ag. Moreover, the antibacterial effect was unchanged after the ZP-Ag dressings were washed 20 times, while it dramatically decreased after the dressings with SD-Ag were washed 20 times. When covered by either regular or washed ZP-Ag dressings, the wounds showed integrity with no visible inflammatory reaction. However, various extents of inflammatory reactions on or around the wounds covered with regular SD-Ag dressing were observed. This study showed that dressings with ZP-Ag had a prominent and relative long-term antibacterial effect. ZP-Ag dressings could be an effective, low-cost management option for burn wounds. [ABSTRACT FROM AUTHOR]

This paper reports the results from investigating the feasibility of calculating flame temperature from a natural gas-fired furnace based on blackbody radiation in the visible spectral range. If successful, the visible spectral range would provide data for multi-task applications such as emission line analysis and temperature calculation simultaneously. A probe containing a lens connected to the fiber-optic cables is inserted into the furnace and pointed towards the flame. Spectral intensity data are fed back to a spectrometer and then to a monitoring computer. The approach is first applied to various furnace types using the visible range to establish a baseline for the technique. The results for temperature calculations in the visible range are then compared with those taken in the near-IR (NIR) range under the same conditions. This comparison indicates that temperatures calculated from visible region could be as accurate as the one obtained from NIR region. Challenges associated with this technique are also discussed. [Copyright &y& Elsevier]

Graphdiyne (GDY), when used as the surface modifier, significantly influences the optoelectronic properties of the perovskite solar cells. To explore such impact for novel high‐performance solar cells, herein, the interfacial interactions and electronic properties of the GDY/CH3NH3PbI3 heterostructures are investigated using density‐functional first‐principles calculations with empirical dispersion corrections. Three interfacial configurations formed by van der Waals interactions are created in nondestructive contact. The calculated charge density differences indicate that the built‐in electric field inside GDY/CH3NH3PbI3 could accelerate the transfer and separation of photoinduced electrons and holes. The enhanced absorption intensity in the visible region of the heterostructures demonstrates the enhancement mechanism of photocatalytic performance. As an effective encapsulation layer, GDY can improve the hole‐transport efficiency and, thus, the device performance. [ABSTRACT FROM AUTHOR]