Gaussian optics optimization of an optical particle counter for measurement in high-pressure gas.

An optimization model for the parameters of the pressure-resistant lens of an optical particle counter, based on Gaussian optics theory, was established to increase the measurement accuracy of the counter for high-pressure natural gas. Comparing the experimental and calculated values of the calibrated model, when the pressure-resistant lens is displaced by 2 mm under atmospheric pressure, the relative error of the measured body deformation is 0.15%. When the air pressure varies in the range 0.10-5.09 MPa, the maximum relative error of optical measurement volume deformation with the change of refractive index is 0.13%, which shows that the model has high reliability and accuracy.

Optimization of the optical particle counter for online particle measurement in pressure-changing natural gas.

Online measurement of particulate matter in high-pressure natural gas is of great significance to the purification process and safe operation of long-distance pipelines. However, pressure changes in high-pressure natural gas pipelines are complicated. The optical particle counter (OPC) is affected by the change in the refractive index of natural gas, which causes an error of the measured particle size. In order to solve this problem, based on the theory of geometric optics, an optimization model of the aerosol tube spherical window regarding the refractive index was established. This optimization basically eliminates the influence of gas refractive index on the OPC beam characteristics, so that OPC has the same performance under any high-pressure conditions as under normal pressure. The problem of the optical sensor being unsuitable for high-pressure conditions in which it is difficult to be calibrated in atmospheric air is solved, and the accuracy of the online particle test in the high-pressure natural gas pipeline is greatly improved. The influence of window thickness and installation error on the optimization model is analyzed, which provides references for improving the accuracy of optical sensors and application design in higher-pressure environments. Finally, the feasibility, reliability, and accuracy of the method are analyzed and verified by experiments.

Substantial Improvement of Oil Aerosol Filtration Performance Using In-Plane Asymmetric Wettability.

Oil aerosol usually causes air pollution, health issues, and corrosion to equipment. The removal of aerosol oil particles from the air is a crucial process in industrial production and daily life. Although fibrous filters have been a widely used material for the separation of oil aerosol from the air, it is still a challenge to separate submicrometer aerosol oil particles with both high filtration efficiency and low resistance. Herein, we report a novel approach to markedly reduce the pressure drop of a fibrous filter and simultaneously increase its aerosol filtration efficiency, only by surface treatment to make the filter have in-plane alternating superoleophilic and superoleophobic patterns. We used a spraying method to prepare superoleophobic and superoleophilic patterns on the filter. The best filtration results were achieved when two layers of the patterned filters that have superoleophobic and superoleophilic strips (both width, 5 mm) were stacked in a way that the opposite wetting surfaces contacted each other between the layers. The filter showed a much-reduced filtration resistance and the pressure drop (4.16 kPa) at the pseudo-steady state being at least 45% lower when compared to the two-layer controls with a homogeneous surface wettability (i.e., untreated surface, superoleophobicity, and superoleophilicity). It also showed higher filtration efficiency (98.37% for small oil mists and 99.99% for large oil mists) and over two times higher quality factor (0.99 kPa-1 for small oil mists and 2.27 kPa-1 for large oil mists). The asymmetric wettability leads to the formation of unobstructed channels for the air stream to penetrate through the filter matrix, leading to a low resistance with improved oil capture efficiency. The pattern strip width showed an effect on filtration performance. This unexpected finding may provide a novel approach to designing high-performance, low energy consumption, and long-life coalescence filters.

Optimization of the optical particle counter for online particle measurement in high-pressure gas.

With the aim to achieve fast and accurate online measurement of particle size and concentration in different high-pressure gas, the application of an optical particle counter (OPC) is extended from atmospheric pressure to high-pressure conditions (more than 2 MPa). But with the increase of the gas pressure, the performance of the OPC is reduced, resulting in the error of the tested particle size. In order to resolve this problem, an optimization model of optical window thickness is established for the optical sensor of the OPC based on the geometric optics theory. The effects of gas pressure, temperature, and medium on the optimized model are analyzed, which are helpful to improve the accuracy of the optical sensor. Finally, the feasibility, reliability, and accuracy of the method are verified through experiments.

Comparative analysis of vertebral transcriptome in Japanese seabass (Lateolabrax japonicus) fed diets with varying phosphorus/calcium levels.

Aquaculture jeopardizes the aquatic environment by discharge of the most dietary phosphorus (P) into the water. Reducing the dietary P level is a common approach for decreasing the P discharge but it may result in increased risk of P deficiency leading to vertebral deformities. However, the molecular mechanism of vertebral deformities is poorly understood. We assessed vertebral transcriptome and compared the genes associated with bone metabolism in Japanese seabass (Lateolabrax japonicus) fed three diets containing different P and Ca levels including: diet I (0.4% P, 0.3% Ca), diet II (0.8% P, 0.3% Ca) and diet III (0.8% P, 3% Ca). The results showed that P deficiency reduces the ossification of vertebrae and induces visible vertebral deformities. Moreover, 256 gens were up-regulated and 125 genes were down-regulated in fish fed P deficient diets. Furthermore, administration of the diet with adequate P and Ca excess (diet III) resulted in the significant enhancement in expression of 19 genes and reduced expression of 93 genes. Comparing group II with group III, expression of 109 genes was up-regulated and expression of 1369 genes was down-regulated. Gene ontology enrichment analysis revealed significant alterations in biological functions by P deficiency. In summary, these findings indicated that both dietary P shortage and Ca excess lead to reduced differentiation and proliferation of osteoblast and induce a higher activity of osteoclastogenesis, which could subsequently impair vertebral mineralization and cause skeletal deformities.

Approach for correcting particle size distribution measured by optical particle counter in high-pressure gas pipes.

A set of online particle detection devices was developed for the quick and accurate assessment of particle size and concentration in high-pressure natural gas that can be applied at any pressure below 10 MPa. In actual site tests with P=3.42 and 2.36 MPa, the online tested results of particle size and concentration are generally smaller compared to those of the offline gathered under atmospheric conditions. That is mainly due to the detection performance degradation of an optical particle counter caused by gas pressure change leading to the refractive index change of the sounding medium with which the optical paths of the incident light and scattering light are altered. Aiming to solve this problem, an analysis of the dynamic change of optical measurement volume of the optical detection system with gas pressure was conducted based on the gas state parameters and geometric optics theory, and a dynamic model of both was established that can be accompanied by a particle size modification method based on light scattering theory. After a correction of tested results, the deviations in median diameter and concentration between the modified online and offline test results were within an acceptable range. Therefore, the proposed modification is a feasible and reliable approach to enhance online particle detection.

Essential role of enhanced surface electron-phonon interactions on the electrical transport of suspended polycrystalline gold nanofilms.

The electrical resistivity of suspended polycrystalline gold nanofilms with different lengths has been measured over the temperature range of 2 K to 340 K, which dramatically increases compared with bulk gold and slightly increases with length. Classical size effect theories considering surface and grain boundary scatterings cannot explain the increased film resistivity, especially the temperature dependence of resistivity, over the whole temperature range. Considering the fact that the reduction of the coordination number of atoms at the surface and the interface leads to a decrease of the phonon spectrum frequency and consequently affects the surface phonon spectrum, the electron-phonon interaction as a relatively independent surface effect is taken into account. The theoretical predictions and the experimental measured film resistivity match very well over the whole temperature range and the extracted surface Debye temperature decreases significantly compared to the bulk value, which illustrates the essential role of enhanced surface electron-phonon interactions on the electrical transport of the present gold nanofilms.

De novo assembly and characterization of seabass Lateolabrax japonicus transcriptome and expression of hepatic genes following different dietary phosphorus/calcium levels.

Fish farming seriously influences the aquatic environment because most dietary phosphorus (P) is excreted in the effluent. To increase the P utilization in fish, molecular techniques should be explored given the remarkable development of these techniques. Thus, to identify the candidate genes related to P utilization and molecular alterations following administration of a P-deficient diet in seabass Lateolabrax japonicus, we assessed the de novo pituitary, gill, intestine, liver, kidney, scales and vertebra transcriptomes, and we compared the expression of hepatic genes with three diets varying in P and Ca levels: diet I (0.4% P, 0.3% Ca), diet II (0.8% P, 0.3% Ca), and diet III (0.8% P, 3% Ca). In total, we identified 99,392 unigenes, and 37,086 (37.31%) unigenes were annotated. The results showed that 48 unigenes were significantly (P<0.05) up-regulated, while 55 genes were significantly down-regulated in the liver of group I compared with group II. Offering the P-sufficient and high Ca diet, diet III significantly up-regulated 24 unigenes and down-regulated 46 genes in the liver. There were significant differences in the regulation of 8 unigenes (3 up-regulated and 5 down-regulated) between groups II and III. Gene ontology (GO) functional enrichment and KEGG pathway analysis of differently expressed genes were performed for each pair of groups. The GO analysis showed that a large number of biological processes were significantly altered between P-deficient and P-sufficient treatments (I vs II and I vs III). Comparing group I and group II, seven KEGG terms were enriched significantly: glycine, serine and threonine metabolism, one carbon pool by folate, arginine and proline metabolism, the biosynthesis of unsaturated fatty acids, fatty acid elongation, drug metabolism-cytochrome P450, and fatty acid metabolism. There was no significantly enriched KEGG pathway between groups II and III. In conclusion, our study revealed that a P-deficient diet could increase catabolism and decrease anabolism of protein, as highlighted by low protein efficiency in fish fed the P-deficient diet. Furthermore, P-deficiency could motivate the biosynthesis of fatty acids. However, the dietary Ca level had no significant effect on the growth and expression of hepatic genes in L. japonicus.