Effects of Radiation Reabsorption on the Laminar Flame Speed and NO Emission during Aviation Kerosene Combustion at Elevated Pressures

Increasing attention has been paid on combustion stability and pollution emission of aviation kerosene due to the emerging interests on supersonic combustion scramjets. Whereas the vitiation component H2O introduced by hydrogen-fueled heaters in high-enthalpy vitiated air during ground experiments has a considerable influence on kerosene combustion, especially through its radiation effect, which needs to be further investigated. In this paper, the radiation reabsorption effects on laminar flame speeds and NO emissions during RP-3/H2O/O2/N2 combustion was assessed numerically over a wide range of equivalence ratio and pressure (ϕ = 0.7–1.4 and P = 1–15 atm) using detailed chemical and radiation models. The surrogate model of RP-3 consisted of vol. 25% 1,3,5-trimethylbenzene (C9H12), 46.31% n-decane (C10H22) and 28.69% iso-dodecane (IC12H26), while the vitiated air had 12% H2O. It was revealed that the radiation reabsorption of H2O in the vitiated air had significant impact on the accurate simulation of laminar flame speeds. As equivalence ratios varied, the role of radiation reabsorption on laminar flame speeds was most pronounced at ϕ = 0.7. As the key radical, the generation of H through the reversed step of CH2OH + H = CH3 + OH was chemically inhibited due to radiation. The radiation reabsorption effect on flame speeds was strengthened with rising pressures, with the reaction H + O2 = O + OH dominant at the pressure range 1–10 atm. In contrast, a slight increase in the impact on laminar flame speeds between 10 and 15 atm was controlled by direct radiative effect. Finally, for NO emission, the reduction of downstream temperature caused by radiative heat loss and the increment of radical concentrations induced by preheating determined radiation reabsorption effects on NO generation

Orbital angular momentum vector modes (de)multiplexer based on multimode micro-ring

Orbital angular momentum (OAM) multiplexing has emerged as an important method to increase the communication capacities in future optical information technologies. In this work, we demonstrate a silicon integrated OAM (de)multiplexer with a very simple structure. By simply tapping the evanescent wave of two different whispering gallery modes rotating inside a multimodal micro-ring resonator, four in-plane waveguide modes are converted to four free-space vector OAM beams with high mode purity. We further demonstrate chip-to-chip OAM multiplexing transmission using a pair of silicon devices, which shows low-level mode crosstalk and favorable link performance

Confined FeNi alloy nanoparticles in carbon nanotubes for photothermal oxidative dehydrogenation of ethane by carbon dioxide

Oxidative dehydrogenation of ethane with CO2 (ODEC) is an attractive reaction for reduction of carbon footprints and ethene production. In this work, we present photothermal catalysis on confined bimetal catalysts for ODEC. Carbon nanotubes confined non-noble bimetal alloy (i.e., CoNi@CNTs and FeNi@CNTs) catalysts were prepared and FeNi@CNTs showed effective performance in photothermal catalytic ODEC to ethene. Experiments and simulations reveal that UV and visible lights (420 – 490 nm) are responsible for ODEC and non-oxidative dehydrogenation of ethane, respectively, to ethene. Additionally, ODEC to ethene is preferred to C-C cracking to methane on FeNi@CNTs in light ( \u3e 490 nm)-induced thermocatalysis. The photothermal effect turns more significant when introduced into thermocatalytic ODEC (500 °C), with ethene generation at one order of magnitude. This work advances new mechanism of photo-mediated catalysis and sheds light on utilization of full-spectrum solar energy and non-noble metallic catalysts for ethene production and CO2 recycling at moderate conditions

Zoonotic Cryptosporidium Parasites Possess a Unique Carbohydrate-binding Protein (Malectin) that is Absent in other Apicomplexan Lineages

Malectin is a carbohydrate-binding protein that binds Glc(2)- N -glycan and is present in animals and some alveolates. This study aimed to characterize the general molecular and biochemical features of Cryptosporidium parvum malectin (CpMal). Polyclonal antibodies were raised for detecting native CpMal by western blotting and immunofluorescence assays. Recombinant CpMal and human malectin (HsMal) were produced, and their binding activities to amylose and the host cell surface were compared. Far-western blotting and far-immunofluorescence assays were used to detect potential binding partners of CpMal in the parasite. Native CpMal appeared to exist in dimeric form in the parasite and was distributed in a diffuse pattern over sporozoites but was highly concentrated on the anterior and posterior sides near the nuclei. CpMal, compared with HsMal, had significantly lower affinity for binding amylose but substantially higher activity for binding host cells. Recombinant CpMal recognized three high molecular weight protein bands and labeled the sporozoite posterior end corresponding to the crystalloid body, thus suggesting the presence of its potential ligands in the parasite. Two proteins identified by proteomics should be prioritized for future validation of CpMal-binding. CpMal notably differs from HsMal in molecular and biochemical properties; thus, further investigation of its biochemical and biological roles is warranted

Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

Cloning of a novel gene from Penicillium oxalicum I1 which in Escherichia coli enhances the secretion of acetic acid

Description of the subject. Organic acids play an important role in the conversion of insoluble ions into soluble ones in soil. Heterologous overexpression of a single gene in a cell is the optimal strategy for increasing the secretion of organic acids solubilizing phosphate. Objectives. In this study, we constructed a primary cDNA library of Penicillium oxalicum I1, and screened clones that can solubilize P in tricalcium phosphate (TCP) medium. We aimed to obtain the gene expressed in Escherichia coli, which can enhance organic acid secretion. Method. A primary cDNA library of Penicillium oxalicum I1 was constructed using the switching mechanism at the 5’-end of RNA transcription. The organic acid secretion ability of E. coli DH5α™ with overexpressed P. oxalicum I1gene was tested in TCP medium where glucose is the sole carbon source. Afterwards, pyruvic acid, citric acid, α-ketoglutaric acid, succinic acid, fumaric acid, and malic acid were used as sole carbon source substitutes for glucose in the TCP medium to test the organic acid secretion ability of the transformed E. coli DH5α™. Results. A total of 106 clones showed halos in TCP medium, among which clone I-2 displayed clear halo. The full-length cDNA of clone I-2 was 1,151 bp, with a complete open reading frame of 702 bp, which encoded a hypothetical protein of 233 amino acids. The cDNA sequence showed 68% identity and 73% query cover with other fungal gene sequences of which the function remains unknown. Escherichia coli containing the cloned gene secreted up to 567 mg.l-1 acetic acid within 48 h. The use of glucose, pyruvic acid, α-ketoglutaric acid, and malic acid improved the acetic acid secretion of the E. coli DH5α™ clone I-2. By contrast, the use of citric acid, succinic acid, and fumaric acid did not improve the acetic acid secretion of clone I-2 compared to a control E. coli DH5α™ strain bearing only the cloning vector without any insert. Conclusions. We obtained a novel gene from Penicillium oxalicum I1 whose overexpression in E. coli DH5α™ increased the secretion of acetic acid. This observation should help to understand what is the function of the gene isolated from P. oxalicum as well as that of its homologs found in several other species of the Penicillium genus

Analysis on Missile-borne Bistatic Forward-looking SAR Imaging Perfomance

Synthetic aperture radar (SAR) has been gradually applied to missile guidance for its advantages of all-weather, all-time and long-distance capabilities. Nevertheless, missile-borne SAR can not image on the area in front of the missile track restricted by SAR working characteristics. Missile-borne forward-looking SAR will be realized through separated transmitter and receiver. Iso-range contours, iso-Doppler contours, ground resolution and azimuth resolution are used to analyze the performance of missile-borne bistatic forward-looking SAR, as to provide the theoretical basis for its application

(3,5-Dimethyl-1H-pyrrol-2-yl)(phenyl)methanone

In the title molecule, C13H13NO, the dihedral angle between phenyl and pyrrole rings is 57.2 (1)°. In the crystal, N—H...O hydrogen bonds link the molecules, forming chains propagating along the b axis

Analysis on Missile-borne Bistatic Forward-looking SAR Imaging Perfomance

Synthetic aperture radar (SAR) has been gradually applied to missile guidance for its advantages of all-weather, all-time and long-distance capabilities. Nevertheless, missile-borne SAR can not image on the area in front of the missile track restricted by SAR working characteristics. Missile-borne forward-looking SAR will be realized through separated transmitter and receiver. Iso-range contours, iso-Doppler contours, ground resolution and azimuth resolution are used to analyze the performance of missile-borne bistatic forward-looking SAR, as to provide the theoretical basis for its application