The reactor coolant pump (RCP) is the only rotating equipment in the primary circuit system of a nuclear power plant and the “heart” of the nuclear reactor. The L formula is defined, and the L/himp is introduced to study the influence of impeller blade type on the performance of the RCP. Twenty groups of models are designed, the concept of arc height ratio is proposed from the perspective of himp and L, and the distribution of internal entropy production within the impeller of the RCP under different Ls and himps of the impeller blade type is analyzed. The results show that when himp remains un-changed and L increases, the low-pressure area at the inlet of the impeller expands while the high-pressure area at the outlet decreases under the design flow or large flow conditions. The smoother blade profile reduces the occurrence of secondary flow phenomena and makes the RCP pressure distribution more uniform. Under design flow and large flow conditions, smaller L/himp and higher himp lead to higher efficiency and head performance. However, higher efficiency and lower head performance can be achieved under small flow conditions with larger L/himp and lower himp.
According to the transverse plate electrostatic precipitator with high velocity collect dust theory, established the laboratory scale transverse plate ESP combines the hydrodynamic, static electrics. In this paper, experiment of ion concentration are carried using the transverse plate ESP. (The laboratory scale transverse plate electrostatic precipitator self-designed) system. The influence rules of the factors to ion concentration are examined such as distance between the export, the discharge electrode, applied voltage, internal of dust collection plates and the gas velocity. According to the experiment result, the ion concentration can increase about 109/cm3, when the working voltage is 18kV, the gas velocity is 4m/s, the distance of effective dust collecting plate is 40mm. The ion concentration of electrostatics precipitator system reaches the maximum and is above 109.
The high gas velocity electrostatic precipitator (HGVESP) is simulated by computational fluid dynamics (CFD) technology. The SIMPLE algorithm is used to calculate and the geometry model is divided by pre-processing software ICEM. The relationship of gas velocity, dust particle size and voltage is examined by FLUENT. The results suggest that with the improvement of applied voltage and dust particle size, collection efficiency increases. The results show that HGVESP with transverse plates can not only have a high efficiency, but also increase treatment capacity, which achieve miniaturization. Then the correctness of the model is verified by experiments.
The process pump as turbine (PPAT) is an important infrastructure in chemical and oil refining process. When it operates in pump mode, it can provide high-pressure energy for chemical and oil refining system, and when it operates in turbine mode, it can recover the high-pressure energy from the oil medium. The operation stability of PPAT directly affects the normal operation and production of chemical and oil refining process. In this paper, the velocity slip characteristics of the PPAT in turbine mode and pump mode were studied, and the unsteady operation characteristics and the energy conversion and distribution mechanism of the first-stage impeller and second-stage impeller in pump mode were mainly studied, the pulsation amplitude frequency characteristics and induction mechanism of flow passage components under different flow conditions in pump mode are analyzed. The results show that PPAT has an efficiency peak in both pump mode and turbine mode, and the efficiency zone is significantly wider and the velocity slip loss is smaller in turbine mode; In turbine mode, with the increase of flow, the velocity slip loss of the first-stage impeller is larger than that of the second-stage impeller; In the pump mode, the velocity slip loss of the first-stage impeller is greater under the conditions of minimum flow and maximum flow, the pressure fluctuation in the PPAT is mainly distributed in the first stage diffuser and the second stage diffuser. The main factor causing the pressure fluctuation in the PPAT is the dynamic and static interference effect between the first-stage impeller and the first-stage diffuser.
Strobilanthes cusia (Nees) Kuntze is a vital medicinal and industrial herb, planted extensively in southern China (Hu, et al. 2011.). In July and August of 2021, leaf spot incidence on >60% plants and reduced yields >20% for fresh leaves were observed in S. cusia cultivar ‘Malan No.1’ across the Shufeng whole Township, Xianyou County, Fujian province. Initial symptoms on leaves were observed as small, dark-brown, spots surrounded by a yellow halo, expanding irregularly or into semicircular spots. As symptoms developed, the spots became dark brown, thin and fragile, forming small holes. In severe cases plants were defoliated. The pathogen was isolated from the margin of 60 symptomatic leaf lesions, surfacesterilized with 75% ethanol for 45 s, rinsed three times with sterile water, air dried, and cultured on PDA at 25°C in the dark. Pure cultures were obtained by single-spore isolation after subculture. Ten representative single-spore isolates (MY-1 to MY-10) from 154 pathogens in 10 sampling points were selected for morphological characterization and identification. After 7 days, mycelial colonies were gray to dark gray with few aerial hyphae. Conidia (32.3 to 132.8 × 5.8 to 8.4 μm, average 81.4 × 6.3 μm, n=50) were pale to brown, erect or curved, solitary or in chains, with 0 to 15 pseudosepta. Based on morphological characteristics, the isolates were preliminarily identified as Corynespora cassiicola. Genomic DNA of isolate MY-2 (randomly selected from 10 isolates as representative) was extracted from mycelia using the Ezup DNA extraction kit (Sangon Biotech Co., Ltd. Shanghai, China). The ITS (internal transcribed spacer) region of rDNA, TEF1-α (translation elongation factor 1 alpha) and TUB2 (beta-tubulin) genes were amplified and sequenced with primers ITS4/ITS5, EF1-728F/EF-986R (Wang et al. 2021) and Bt2a/Bt2b (Glass et al. 1995), respectively. BLASTN sequence analyses of ITS (538 bp), TEF1-α (302 bp) and TUB2 (436 bp) of isolate MY-2 (GenBank accessions OK355515, OM339443, OM339442) showed 100%, 97.6%, 100% identity with C. cassiicola in GenBank (Accession numbers JX908713, MW961421, AB539228). A neighbor-joining phylogenetic analysis based on ITS and TEF1-α sequences using MEGA7 showed that MY-2 clustered in the same clade with C. cassiicola. For pathogenicity tests, five S. cusia plants were inoculated onto the adaxial surface of leaves with mycelial plugs from ten isolates of 8-day-oldcultures on PDA. Five leaves per plant were inoculated, covered with wet cotton, and kept in a controlled greenhouse (26~33 °C, RH 80% ~ 90%). Leaves inoculated with sterile PDA plugs served as a negative control. At 3-5 days post inoculation, all 25 inoculated leaves of each isolate showed leaf spot lesions similar to those observed in the field, and control leaves were symptomless. C. cassiicola was successfully reisolated from the diseased leaves. The pathogenicity tests were repeated three times under the same conditions and similar results were observed. In view of morphology, pathogenicity and sequence results, the isolates were identified as C. cassiicola, a pathogen reported from many important crops (Lu et al. 2021). This is the first report of C. cassiicola as a pathogen in China which poses a potential threat to leaf production and S. cusia processing. References: Glass, N. L., et al. 1995. Appl. Environ. Microb. 61:1323 Hu, J.Q., et al. 2011. Flora of China. Science Press, Beijing, China. Volume 19: 407 Li, Q.L., et al. 2013. Plant Dis. 97 (5): 690 Lu, P. et al. 2021. Plant Dis. 105:3753 Wang S. H., et al. 2021.Forest Pathology, 51(2):1 Keywords: fungal disease, Strobilanthes cusia, medicinal plants, etiology, leaf spot
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