Theoretical Ratio Research Articles

Synthesis, characterization, and investigation of photoluminescence optima of In3+ and Gd3+ doped Eu1.90In0.10Ru2O7 and Eu1.90Gd0.10Ru2O7 materials

In this study, we investigated the photoluminescence properties and structure of the In3+ and Gd3+ doped Eu2Ru2O7-based pyrochlore materials. The samples were synthesized by solid state reaction technique, investigated structurally by X-ray powder diffraction (XRD), thermally by thermogravimetry, and differential thermal analysis, morphologically by scanning electron microscopy (SEM). The photoluminescence properties of Eu1.90In0.10Ru2O7 and Eu1.90Gd0.10Ru2O7 were investigated with photoluminescence spectrometer. X-ray diffraction patterns of all the samples showed that all samples had a cubic type pyrochlore crystal structure with a = b = c = 10.252 Å and α = β = γ = 90°. The XRD patterns demonstrate that neither the type nor the amount of doping ion alters the unit cell parameter. The SEM images of Eu1.90In0.10Ru2O7 and Eu1.90Gd0.10Ru2O7 reveal a regular morphology, with an average sample size ranging from 0.2 to 0.5 μm. The elementel (EDX) analysis confirm the absence of impurity elements and showing that the theoretical and experimental element ratios are consistent with EDX analysis expectations. The pyrochlore phosphors showed broad red emission band at ∼605 nm. This red emission can be attributed to the 5D0→7F2 transitions of Eu3+. The phosphor co-doped with In3+ ions has a considerably longer lifetime and photoluminescence intensity than the other phosphor. Eu1.90In0.10Ru2O7 and Eu1.90Gd0.10Ru2O7 phosphors, which show transitions in the red region (at 605/606 nm,5D0 →7F2), are suitable for optoelectronic and white LED applications.

OPTIMAL SAMPLING RATIO FOR IMBALANCED DATA

Artificial sampling is one of the main approaches to dealing with imbalanced data. However, despite a vast amount of research on sampling techniques, there is little known about the choice of the optimal sampling ratio which can significantly improve the classification accuracy. In this paper, we attempt to fill the gap in the literature by conducting both mathematical and numerical analysis. Concretely, we conduct a large-scale empirical study on the relationship between the sampling ratio and classification accuracy. In addition, we investigate the theoretical sampling ratio using the Bayesian approach and obtain the optimal ratio of √1 e ≈ 0.6065 which is in line with the results of the numerical experiments. We find that while factors such as the original imbalance ratio or the number of features do not play a discernible role in determining the optimal ratio, the number of samples in the dataset may have a tangible effect. We hope that the insights revealed in this study will help researchers and practitioners select the optimal sampling ratio when dealing with imbalanced data.

Sustainable and Self-Sufficient Fresh Water Through MED Desalination Powered by a CPV-T Solar Hybrid Collector: A Numerical and Experimental Study

The effects of global warming are severely recognizable and, according to the OECD, 47% of the world’s population will soon live in regions with insufficient drinking water. Already, many countries depend on desalination for fresh water supply, but such facilities are often powered by fossil fuels. This paper presents an energy self-sufficient desalination system that runs entirely on solar power. Sunlight is harvested using parabolic trough collectors with an effective aperture area of 1.5 m × 0.98 m and a theoretical concentration ratio of 150 suns, in which a concentrator photovoltaic thermal (CPV-T) hybrid-absorber converts the radiation to electricity and heat. This co-generated energy runs a multi-effect distillation (MED) plant, whereby the waste heat of multi-junction concentrator solar cells is used in the desalination process. This concept also takes advantage of synergy effects of optical elements (i.e., mirrors), resulting in a cost reduction of solar co-generation compared to the state of the art, while at the same time increasing the overall efficiency to ~75% (consisting of an electrical efficiency of 26.8% with a concurrent thermal efficiency of 48.8%). Key components such as the parabolic trough hybrid absorber were built and characterized by real-world tests. Finally, results of system simulations, including fresh water output depending on different weather conditions, degree of autonomy, required energy storage for off-grid operation etc. are presented. Simulation results revealed that it is possible to desalinate around 2,000,000 L of seawater per year with a 260 m2 plant and 75 m3 of thermal storage.

Anaerobic oxidation of methane coupled to reductive immobilization of hexavalent chromium by “Candidatus Methanoperedens”

The anaerobic oxidation of methane (AOM) carried out by anaerobic methanotrophic archaea (ANME) plays an important role in mitigating methane emissions from aqueous environments and has applications in bioremediation and wastewater treatment. Previous studies showed that AOM could be coupled to chromate reduction. However, the specific responsible microorganisms and the biochemical mechanisms are unclear. Herein, we showed that a consortium dominated by ANME “Candidatus Methanoperedens” was able to couple AOM to the reduction of Cr(VI) to Cr(III) at a stoichiometry close to the theoretical ratio. Quantitative distribution analysis of Cr(III) products suggested Cr(VI) was predominantly reduced via the extracellular respiratory pathways. Further Cr(III)-targeted fluorescent visualization combined with single-cell electron microscopic imaging suggested that Cr(VI) was reduced by “Ca. Methanoperedens” independently. Biochemical mechanism investigation via proteomic analysis showed proteins for nitrate reduction under nitrate-reducing conditions were significantly downregulated in Cr(VI)-reducing incubation. Instead, many multiheme cytochrome c (MHCs) were among the most upregulated proteins during the Cr(VI) reduction process, suggesting MHC-governed pathways for extracellular Cr(VI) reduction. The significant upregulation of a formate-dependent nitrite reductase during Cr(VI) reduction indicated its potential contribution to the small proportion of Cr(VI) reduction inside cells.

Ceria and nitrogen decorated Ca-BTC-derived carbon with residual CaO for CO2 adsorption

Calcium oxide (CaO) is a high-temperature CO2 capture sorbent. However, it suffers from CaO aggregation for CO2 scrubbing after looping cycles. To disperse and secure CaO, in this research, we pyrolyzed Ca-based metal-organic frameworks (MOFs) Ca-BTC for CaO on MOF-derived carbon (MDC). Furthermore, ceria or nitrogen was introduced into Ca-MDC by Ce2+ or DABA ligand addition to Ca-BTC. Compared to pure CaO, Ca-MDC maintained 30 % better CO2 adsorption stability after 10 cycles. In comparison, the CO2 uptake of CeO2-decorated Ca-MDC kept at about 100 % after 10 cycles, which could be attributed to oxygen vacancy in CeO2. The highest CO2 adsorption reached 17.10 mmol/g in N-doped Ca-MDC with 80 % stability. All CaO on MDC samples had CO2 adsorption exceeding the theoretical stoichiometric ratio 1:1 of CaO:CO2, implying plausible CO2 spillover from CaO to carbon matrix. For kinetics analyses, the pseudo-second order (PSO) model showed a better fit than the linear driving force (LDF) model, suggesting strong chemisorption in CaO as expected. The double exponential (DE) model was applied to differentiate CO2 chemisorption and surface diffusion and showed much higher diffusion rate constants in Ca-MDC than CaO, suggesting a possible CO2 spillover phenomenon.

Design and performance characteristics of single-axis tracking dual confocal low-magnification parabolic trough CPV system

With the rapid increase of PV module utilization, the environmental pollution associated with waste photovoltaic (PV) module and its recycling is of concern. This paper proposes a concentrating photovoltaic (CPV) system to reduce the use of PV module. The cross-confocal method is employed for the concentrator to eliminate central dark streaks. In optical simulation, a theoretical uniformity index of 0.0466 and a theoretical optical efficiency of 89.87 % were achieved. When the distance between the rotational axis and the center of gravity is less than 125.8 mm, the system can withstand winds of 20.4 m/s. The temperature range of the PV, obtained from finite element analysis, is from 295.71 K to 363.13 K. With the requirements of the relative optical efficiency of over 90 % and the uniformity index of less 0.5, the system has a dimensional translation tolerance of approximately ±10 mm, a dimensional rotation tolerance of about 5°, and a tracking angle tolerance of about 1°. The actual daily average output current of this system has increased by 100.91 %. The ratio between the increase ratio of output current and the theoretical concentration ratio is 83.4 %. The system demonstrates excellent optical performance and system tolerance.

Tragacanth Gum/Trimethyl Chitosan‐Derived Polyelectrolyte Complex as Potential Carriers in Drug Delivery Applications

ABSTRACTA three‐step procedure described in the literature has been used to create N,N,N‐trimethyl Ct a chitosan derivative that is extremely soluble in water. By combining two polymers in aqueous media, this derivative and tragacanth gum were able to form a new polyelectrolyte complex. The TGA, FTIR, and DSC analysis established the development of TMC/XG‐PEC. SEM was used to describe the TMC/TG‐PEC's surface morphology. The features of diffusion and swelling, such as the theoretical equilibrium ratio, initial swelling rate constant, and the process of water transportation into TMC/TG‐PEC, were established. The TMC/TG‐PEC swelling is seen to be pH‐dependent. It swells in the subsequent order: pH 7.4 > 6.8 > 1.2. At pH 1.2, 6.8, and 7.4, the TMC/TG‐PEC swelling ratio was found to be 6.5, 7.7, and 9.6 g/g, respectively. The second‐order kinetics of the swelling process is indicated by the linearity of the plot “t/SR” versus “t”. The TMC/TG‐PEC's n values under various pH circumstances ranged from 0.12 to 0.16, suggesting the Fickian water transport mechanism. The utility of complex as a matrix for KP formulations for sustained‐release tablets was investigated. It was discovered that 90.5% of KP was loaded into PEC. There is evidence that pH influences how much medicine is released. When the medium's pH was altered from acidic to neutral, the KP release was considerably boosted. The TMC/TG‐PEC demonstrated a maximum drug release of 7% in a pH 1.2 medium and between 85% and 90% in a pH 7.4 medium, demonstrating the TMC/TG‐PEC's potential as a matrix substance for the drug's prolonged release formulations of KP. The Fickian drug transport mechanism was indicated by the release exponent n, which was less than 0.5.

Template-synthesized CdWO4/Cd0.5Zn0.5S hollow microsphere photocatalyst for high-efficient hydrogen evolution under visible light

Photocatalytic water splitting for hydrogen production is a promising strategy for renewable energy. While Cd1-XZnXS catalysts display high photocatalytic hydrogen evolution efficiency in pure water, they are limited by severe photocorrosion and rapid recombination of electron–hole pairs. In this study, HGM (hollow glass microspheres) was used as the support template, Cd0.5Zn0.5S and CdWO4 were successively coated on the template by hydrothermal method. The tightly packed heterojunction interface between the coatings ensures efficient electron transport and suppresses the recombination of electron-hole pairs. Under visible light irradiation, when the theoretical mass ratio of Cd0.5Zn0.5S to CdWO4 is 4:1, the Cd0.5Zn0.5S/CdWO4-25% hollow microsphere photocatalyst exhibits the highest hydrogen evolution rate, reaching 41.40 mmol g−1 h−1, which is approximately 3.4 times higher than the hydrogen evolution rate of pure Cd0.5Zn0.5S (12.31 mmol g−1 h−1). This research provides a novel approach for the design and synthesis of efficient and stable photocatalysts.

A novel design approach based on sequential-conjugate method for high-mesh-ratio harmonic drives with dual-conjugate profiles and polynomial wave generators

The tooth profiles and meshing ratio of the flexsplines and circular-splines in harmonic drives have attracted significant research attention, especially for applications requiring high-torque. The present study proposes a new five-phase method for the design of the wave generator profile and all the tooth profiles in the harmonic drive. Once the upper profile of rack-cutter has been given, the proposed method enables all of the other undefined tooth profiles in harmonic drive (including the upper/lower-profiles of the flexspline/circular-spline and the lower-profile of the rack-cutter) to be constructed using a sequential-conjugate approach. The designed tooth profiles achieve a high meshing ratio, and thus reduce the transmission load. Notably, part of the period during the meshing process is dual-conjugate (i.e. the flexspline and circular-spline have two meshing points simultaneously). Furthermore, the profile of wave generator is defined as a polynomial curve, which thus provides greater design freedom for any follow-up optimization task. An illustrative example is presented to demonstrate the effectiveness of the proposed method for a harmonic drive with a three-tooth difference and a wave generator based on a quintic polynomial. The results show that the theoretical meshing ratio is as high as 81%, and the dual-conjugate region accounts for 23% of total conjugate region.

Impact of liquid crossflow on the discharge coefficient of a gas jet hole on a flat plate

This study combines the experimental and numerical simulation methods to deeply analyze the impact of liquid crossflow on the discharge coefficient of a gas jet hole on a flat plate. Experiments were conducted to examine the influence of momentum flux ratio and theoretical momentum flux ratio on the discharge coefficient under various crossflow Reynolds numbers. It was found that the variation of the discharge coefficient with the theoretical momentum flux ratio clearly reflects the impact of the crossflow boundary layer velocity profile on the discharge coefficient. The rapid growth of velocity in the boundary layer near the wall in the direction normal to the wall surface, or the decrease in the thickness of the boundary layer, both enhance the shearing effect of the crossflow, leading to a decrease in the discharge coefficient. Analysis of the cavity morphology at the hole exit captured by high-speed camera revealed that the averaged profile of the gas–liquid boundary on the symmetrical plane of the jet below the hole can be approximated as a straight line within the scale of the hole diameter, and the sine of the angle between this line and the upper wall surface is roughly equivalent to the normalized discharge coefficient. This relationship was physically interpreted through the analysis of effective and equivalent flow cross-sectional shapes derived from numerical simulation at different crossflow Reynolds numbers and theoretical momentum flux ratios. Additionally, this paper introduces an innovative method for predicting jet flow rate based on image processing technology. A notable feature of this method is that it does not require the measurement of the pressure inside the gas chamber.

Experimental identification of longitudinal and vertical lift aerodynamic admittance functions of thin sections

Previous studies of two-dimensional (2D) aerodynamic admittance function (AAF) identification methods have basically ignored the effects of different turbulence components, which may lead to unpredictable errors for practical engineering applications. This paper presents pressure measurement experiments on thin sections with a geometric ratio of 1:50 in various turbulent fields. Based on the three-dimensional (3D) two-wavenumber theoretical analytical framework, the two-wavenumber coherence function is obtained by fitting the measured spanwise root-coherence function at the effective spacing with an empirical model. A new method is proposed, assuming that the ratio relationship between the lift AAFs due to longitudinal and vertical turbulence components of the measured model section satisfies its corresponding theoretical solution ratio relationship. The 2D lift AAFs of the airfoil section induced by different turbulence components are identified following the proposed identification framework. Consistent with the previous research, force correlation is significantly larger than turbulence correlation, and the traditional 3D one-wavenumber AAFs obtained are different in different turbulent fields. The separated 2D lift AAFs demonstrate that the contributions of u- and w- turbulence to the buffeting lift force are significantly different, and are more precise, according to the ratio between the Horlock function and Sears function. Then, the method is successfully extended to estimate the AAFs with respect to the u- and w-turbulence components of a streamlined box girder section, further validating the applicability of the identification method to the streamlined box girder. Furthermore, comparing the separated 2D lift AAFs under different turbulence fields reveals their independence from turbulence characteristics.

Electro-responsive superabsorbent hydrogel based on carboxymethyl cellulose as a draw agent for forward osmosis desalination

To explore a simple and energy-efficient approach to regenerate draw agent is a key challenge for forward osmosis (FO) desalination. Electro-responsive hydrogels have attracted great attention due to their reversible swelling-shrinking behaviors under an electric stimulus. However, the developed electro-sensitive hydrogels based on 2-acrylamido-2-methyl-l-propanesulfonic acid (AMPS) so far exhibit low reusability due to their unstable electro-sensitive properties and poor degradability with potential environmental impact. This study explored the use of an electro-responsive superabsorbent hydrogel as a draw agent by grafting acrylic acid (AA) and acrylamide (AM) onto sodium carboxymethyl cellulose (CMC). The grafted hydrogel’s morphology and structure were investigated by FTIR and SEM. The swelling behaviors and deswelling properties in an electrode contact system were examined. The swelling kinetics of the hydrogel could be well described by the Schott's pseudo-second-order model with a theoretical swelling ratio of 452.5 g/g. The grafted hydrogel exhibited stable electro-sensitive characteristics with a decrease of 7.3 % in the equilibrium swelling ratio after undergoing three cycles of deswelling and swelling. During the FO test, the dry hydrogel particles produced a water flux of 1.55 L·m−2·h−1 within the first hour, surpassing the performance of other carboxylic acid-based hydrogels used as draw agents. Significantly, it exhibited encouraging water recovery capabilities in the five recycling FO processes, retaining around 84 % of its initial water recovery ratio after 40 min of exposure to a voltage of 15 V. This indicated that the grafted hydrogel could be considered as an effective and sustainable draw agent for FO desalination.

Toward Methanol Production by CO2 Hydrogenation beyond Formic Acid Formation.

ConspectusThe Paradigm shift in considering CO2 as an alternative carbon feedstock as opposed to a waste product has recently prompted intense research activities. The implementation of CO2 utilization may be achieved by designing highly efficient catalysts, exploring processes that minimize energy consumption and simplifying product purification and separation. Among possible target products derived from CO2, methanol is highly valuable because it can be used in various chemical feedstocks and as a fuel. Although it is currently produced on a plant scale by heterogeneous catalysis using a Cu/ZnO-based catalyst, a limited theoretical conversion ratio at high reaction temperatures remains an issue. In addition, a catalytic system that can be adjusted to accommodate a variable renewable energy source for the synthesis of methanol is more desirable than current continuous-operation systems, which require a reliable energy supply. Recently, significant progress has been made in the field of homogeneous catalysis, which primarily relies on an indirect route to synthesize methanol via the hydrogenation of carbonate or formate derivatives in the presence of additives and solvents. However, homogeneous catalysis is inappropriate for industrial-scale methanol production because of the inefficient separation and purification processes involved.In this Account, we demonstrate a novel approach for methanol production under mild reaction conditions by CO2 hydrogenation catalyzed by multinuclear iridium complexes under heterogeneous gas-solid phase conditions without any additives and solvents. One of the aims of this Account provides insights for overcoming the barriers for efficient CO2 hydrogenation by focusing on catalyst design, specifically by incorporating varying functionalities into the ligand. The fundamental strategy entails activating hydrogen molecule and enhancing the hydricity of the resulting metal-hydride species, which is based on the following two concepts of catalyst design: (i) Activating a metal-hydride by electronic effects; and (ii) accelerating H2 heterolysis. We have elucidated the mechanism for accelerating H2 heterolysis using a state-of-the-art catalyst that contains an actor-ligand that responds to or participates in catalysis as opposed to a classical spectator-ligand.We have also demonstrated a novel heterogeneous catalysis using a molecular catalyst as a key step for the hydrogenation of CO2 to methanol beyond formic acid formation. The dehydrogenation of formic acid as a reverse reaction of formic acid hydrogenation is strongly favored in acidic aqueous solution. To circumvent the equilibrium limitation, we have envisioned an alternative route that both prevents the liberation of formic acid into the reaction medium, and develops a multinuclear complex to facilitate the transfer of multiple reactive hydrides. The unconventional gas-solid phase catalysis is capable of preventing the liberation of formate species and promoting further hydrogenation of formic acid through multihydride transfer.This novel catalytic system, which is the fusion of a molecular catalyst in heterogeneous catalysis, provides high performance for methanol synthesis through a sophisticated catalyst design and straightforward separation processes. A detailed mechanistic analysis of molecular catalysts in the gas phase would lead to significant progress in the field of Surface Organometallic Chemistry (SOMC).

Dynamics of HCN, HNC, and HNCO Formation in the 193 nm Photodissociation of Formamide.

Formamide (NH2CHO) is the simplest molecule containing a peptide linkage [-NH-C(═O)-], and it plays an essential role in the study of prebiotic chemistry. Exposure to UV irradiation allows formamide to decompose and act as a prebiotic feedstock in the formation of nucleobases and other necessary starting materials. The photodissociation mechanism of gaseous formamide at 193 nm is studied using (a) chirped-pulse Fourier transform millimeter-wave spectroscopy in the 260-290 GHz spectral region in a room-temperature flow-tube reactor at 1 μbar pressure, (b) a combination of electronic structure theory, transition state theory, and quasiclassical trajectories, and (c) the Active Thermochemical Tables. The HCN and HNC photoproducts of hydrogenated (NH2CHO) and deuterated (NH2CDO and ND2CHO) formamide precursors are examined to gain insight into the photodissociation mechanism. The theoretical investigation has characterized the main pathway leading to each of the HCN/HNC isomers from the precursor isotopologues. The theoretical branching ratio [HNC]/[HCN] = 2.1 for nascent photofragments agrees with the experiment. The effect of the postphotolysis HNC ↔ HCN isomerization on the [HNC]/[HCN] ratio is predicted. We report the experimental branching ratio [HNCO]: ([HNC] + [HCN]) = 12 ± 3 and propose that most of HNCO originates from dissociation on the S1 electronic state of formamide.

Quantifying the viability of lactic acid bacteria using ratiometric fluorescence assays

Quantifying the viability of lactic acid bacteria (LAB) has become an important task in evaluating the quality, function and storage condition of LAB products. Propidium iodide (PI), as a DNA-binding dye that penetrates only dead bacteria, has been widely used for LAB viability assessments. However, high fluorescence background from live LAB was frequently occurred during PI-based staining, which led to the low sensitivity in probing minor amounts of dead LAB in a dead/live mixture. Here, we found that PI could be adsorbed nonspecifically in LAB periplasm, which contributed to the high fluorescence background of live LAB. CaCl2 was used to reduce this nonspecific adsorption and increase the fluorescence ratio of dead to live LAB. Combined with SYTO 9 (a membrane permeable dye) for double-staining, a ratiometric fluorescent method that could probe dead LAB at a ratio as low as 0.2 % was established. Using Lacticaseibacillus casei as a LAB model, an allometric correlation between the ratiometric fluorescence and theoretical ratio of live to dead LAB was acquired, with a correlation coefficient R2 of 0.993. The as-developed method was successfully applied to the viability assessment of LAB stored in different environments. We believe it would have practical applications in LAB food industry for quality management and control.

A novel 4H–SiC thermal neutron detector based on a metal-oxide-semiconductor structure

Energy resolution and leakage current are two key parameters for semiconductor neutron detectors. Metal-Oxide-Semiconductor (MOS) detectors introduce an additional oxide layer compared to Schottky Barrier Diodes (SBDs) detectors in order to reduce leakage current. However, this also leads to a degradation in energy resolution due to the introduction of an additional dead layer. Therefore, optimizing the thickness of the oxide layer is important for MOS detectors. In this study, a 4H–SiC-based MOS thermal neutron detector was designed with comprehensive consideration of the oxide layer. Subsequently, a prototype of the detector was fabricated and tested. The prototype of the MOS detector achieved an nA-level leakage current under a reverse bias of −200 V. Additionally, it demonstrated good energy resolution performance in a moderated D-T neutron source test. The MOS detector was able to clearly distinguish between the two reaction channels of 10B converter events, which is consistent with the theoretical branching ratio. This work highlights the potential application of 4H–SiC-based MOS detectors for thermal neutron detection.

Design and Optimization of Molecularly Imprinted Polymer Targeting Epinephrine Molecule: A Theoretical Approach.

Molecularly imprinted polymers (MIPs) are a growing highlight in polymer chemistry. They are chemically and thermally stable, may be used in a variety of environments, and fulfill a wide range of applications. Computer-aided studies of MIPs often involve the use of computational techniques to design, analyze, and optimize the production of MIPs. Limited information is available on the computational study of interactions between the epinephrine (EPI) MIP and its target molecule. A rational design for EPI-MIP preparation was performed in this study. First, density functional theory (DFT) and molecular dynamic (MD) simulation were used for the screening of functional monomers suitable for the design of MIPs of EPI in the presence of a crosslinker and a solvent environment. Among the tested functional monomers, acrylic acid (AA) was the most appropriate monomer for EPI-MIP formulation. The trends observed for five out of six DFT functionals assessed confirmed AA as the suitable monomer. The theoretical optimal molar ratio was 1:4 EPI:AA in the presence of ethylene glycol dimethacrylate (EGDMA) and acetonitrile. The effect of temperature was analyzed at this ratio of EPI:AA on mean square displacement, X-ray diffraction, density distribution, specific volume, radius of gyration, and equilibrium energies. The stability observed for all these parameters is much better, ranging from 338 to 353 K. This temperature may determine the processing and operating temperature range of EPI-MIP development using AA as a functional monomer. For cost-effectiveness and to reduce time used to prepare MIPs in the laboratory, these results could serve as a useful template for designing and developing EPI-MIPs.

Dependence of Pressure Characteristics of Pressurized Pulse Water Jet Chamber on Nozzle Diameter

The nozzle is the key element of the water jet generator for energy conversion. In order to explore the influence of the nozzle diameter on the pressure characteristics of the supercharged pulsed water jet plenum chamber, a supercharged pulsed water jet pressure acquisition system was established, and the equations of motion and theoretical pressurization ratio equations of the supercharged pulsed water jet generator were established. The pressurization chamber pressure acquisition experiments under different nozzle diameters were carried out. The research results show that the pressurized pulsed water jet generator has a critical nozzle diameter of 0.6 mm. When the nozzle diameter is less than the critical diameter, the pressure in the boost chamber is equal to the product of the driving pressure and the boost ratio. As the nozzle changes, there is no significant change in the peak pressure and frequency of the boost chamber. When the nozzle diameter is greater than the critical diameter, there is a non-linear relationship between the boost chamber pressure and the driving pressure. As the nozzle diameter gradually increases, the actual boost ratio gradually decreases, and the peak pressure of the boost chamber further decreases. The nozzle diameter can no longer provide a load for the establishment of fluid pressure in the boost chamber. The results of this research provide a research basis for further controlling the pressure characteristics of the boost pulse water jet.

Rapid and Sensitive Quantification of Bacterial Viability Using Ratiometric Fluorescence Sensing.

Bacterial viability assessment plays an important role in food-borne pathogen detection and antimicrobial drug development. Here, we first used GelRed as a DNA-binding stain for a bacterial viability assessment. It was found that live bacteria were able to exclude GelRed, which however could easily penetrate dead ones and be absorbed nonspecifically on the bacterial periplasm. Cations were used to reduce the nonspecific adsorption and greatly increase the red fluorescence ratio of dead to live bacteria. Combined with SYTO 9 (a membrane-permeable dye) for double-staining, a ratiometric fluorescent method was established. Using Escherichia coli O157:H7 as a bacteria model, the ratiometric fluorescent method can probe dead bacteria as low as 0.1%. A linear correlation between the ratiometric fluorescence and the theoretical ratio of dead bacteria was acquired, with a correlation coefficient R2 of 0.97. Advantages in sensitivity, accuracy, and safety of the GelRed/SYTO9-based ratiometric fluorescent method against traditional methods were demonstrated. The established method was successfully applied to the assessment of germicidal efficacy of different heat treatments. It was found that even 50 °C treatment could lead to the death of minor bacteria. The as-developed method has many potential applications in microbial researches, and we believe it could be expanded to the viability assessment of mammalian cells.

Research on Blast Furnace Ingredient Optimization Based on Improved Grey Wolf Optimization Algorithm

Blast furnace ironmaking plays an important role in modern industry and the development of the economy. A reasonable ingredient scheme is crucial for energy efficiency and emission reduction in blast furnace production. Determining the right blast furnace ingredients is a complicated process; therefore, this study examines the optimization of the ingredient ratio. In this paper a model of the blast furnace ingredients is established by considering cost of per ton iron, CO2 emissions, and the theoretical coke ratio as the objective functions; ingredient parameters, process parameters, main and by-product parameters as variables; and the blast furnace smelting theory and equilibrium equation as constraints. Then, the model is solved by using an improved grey wolf optimization algorithm and an improved multi-objective grey wolf optimization algorithm. Using the data collected from the steel mill, the conclusion is that multi-objective optimization can consider the indexes of each target, so that the values of all the targets are excellent; we also compared the multi-objective solution results with the original production scheme of the steel mill, and we found that using the blast furnace ingredient scheme optimized in this study can reduce the cost of iron per ton, CO2 emissions per ton, and the theoretical coke ratio in blast furnace production by 350 CNY/t, 1000 kg/t, and 20 kg/t, respectively, compared with the original production plan. Thus, steel mill decision makers can choose the blast furnace ingredients according to different business strategies and the actual needs of steel mills can be better met.