Super-directivity formation and numerical analysis of acoustic array

The formation of super-directivity of an acoustic array is firstly analyzed to construct a general mathematical model of the array with super-directivity and maximum signal-to-noise ratio (SNR). Then the numerical simulation on the super-directivity of the array is carried out for the arrays with different shapes, element number and apertures. It shows that, circular array with regular shape and Archimedean spiral array with irregular shape have optimum directivity

Model and Frequency Control for Three-Phase Wireless Power Transfer System

In order to the eliminate the “dead spot” in the traditional three-phase wireless power transfer (WPT) system, a three-phase WPT system with an asymmetric magnetic circuit is presented in this paper. Additionally, mathematical model of the system is established and the system parameters are optimized. Based on the fact that the resonant frequency and efficiency are greatly varied with the load, a method based on impedance conversion is further proposed to improve the frequency stability and system efficiency. Finally, simulation and experimental results show that the proposed method is reliable and feasible to eliminate the “dead spot.

Research Progress in Anaerobic Digestion of High Moisture

High moisture organic waste constitutes a large fraction of municipal solid waste and caused a nuisance. Anaerobic digestion of this high degradable fraction has been developed during the past 20 years. Parameters such as characteristic of substrates, temperature, organic loading rate and hydraulic retention time were studied. The most important conversion of intermediate of volatile fatty acid was observed as a indicator of digestion efficiency. One stage and two stage system are based on the stage separated into acidogenic phase and methnogenis phase. Two stage digestion of this kind of wastes were proved a better efficiency than single stage digestion. Batch system and continuous system are conducted in single stage and two-stage system. One stage system are split between wet system(Total solid less than 15%) and dry system( total solid higher than 15%) according to the characteristics of feedstock. Two-stage solid bed system are observed more and more popular in the digestion of solid state VFW and food waste experimental studies, however the large majority of industrial application use single stage systems. Two stage digestion of HMOW will be applied to industrial scale due to its larger resistance to high loading rate, high and stable gas production

Super-directivity formation and numerical analysis of acoustic array

The formation of super-directivity of an acoustic array is firstly analyzed to construct a general mathematical model of the array with super-directivity and maximum signal-to-noise ratio (SNR). Then the numerical simulation on the super-directivity of the array is carried out for the arrays with different shapes, element number and apertures. It shows that, circular array with regular shape and Archimedean spiral array with irregular shape have optimum directivity

A comparative study on the mineralogy, chemical speciation, and combustion behavior of toxic elements of coal beneficiation products

The huge demand for high-quality coal in China has resulted in increased generation of preparation plant wastes of various properties. A series of beneficiation products collected from a preparation plant were characterized to understand their petrographic and mineralogical characteristics, as well as thermochemical and trace element behavior during combustion. The minerals in the Luling preparation plant wastes from Huaibei coalfield mainly included kaolinite and quartz, with minor calcite, ankerite, pyrite, illite, chalcopyrite, albite, K-feldspar, anatase/rutile, and iron-oxide minerals. Massive clay lumps of terrigenous origin, cleat-infilling carbonate, and pyrite of epigenetic origin were prone to be enriched in the middlings and coal gangue. Minor or trace heavy minerals also reported to the preparation plant wastes. The contents of low-density density vitrinite and liptinite were enhanced in the clean coal, while inertinite-maceral group were enriched in the middlings. The modes of occurrences of toxic elements differed between raw coal and the waste products; and their transformation behavior during heavy medium separation is largely controlled by clay minerals (V, Cr, Co, Sb, and Pb), carbonate minerals (Co and Pb), sulfide minerals (As, Cu, Ni, Cd, and Zn) and organic matters (V, Cr, Se, and Cu). Three groups were classified based on the volatile ratio (Vr) of toxic elements. Group 1 includes the highly volatile element Se with Vr &gt; 85%; Group 2 contained elements As, Pb, Zn, Cd and Sb, with the Vr in the range of 20&ndash;85% and V, Cr, Co, Ni and Cu with Vr less than 20% were placed into Group 3. Thermal reactivity of coal inferred from the combustion profiles could be significantly improved after coal beneficiation, whereas the increased inorganic components probably inhibited the thermal chemical reaction of wastes.<br style="line-height: normal; text-align: -webkit-auto; text-size-adjust: auto;" /

Transcriptome analysis provides insights into the cell wall and aluminum toxicity related to rusty root syndrome of Panax ginseng

Rusty root syndrome is a common and serious disease in the process of Panax ginseng cultivation. This disease greatly decreases the production and quality of P. ginseng and causes a severe threat to the healthy development of the ginseng industry. However, its pathogenic mechanism remains unclear. In this study, Illumina high-throughput sequencing (RNA-seq) technology was used for comparative transcriptome analysis of healthy and rusty root-affected ginseng. The roots of rusty ginseng showed 672 upregulated genes and 526 downregulated genes compared with the healthy ginseng roots. There were significant differences in the expression of genes involved in the biosynthesis of secondary metabolites, plant hormone signal transduction, and plant–pathogen interaction. Further analysis showed that the cell wall synthesis and modification of ginseng has a strong response to rusty root syndrome. Furthermore, the rusty ginseng increased aluminum tolerance by inhibiting Al entering cells through external chelating Al and cell wall-binding Al. The present study establishes a molecular model of the ginseng response to rusty roots. Our findings provide new insights into the occurrence of rusty root syndrome, which will reveal the underlying molecular mechanisms of ginseng response to this disease

Distribution, occurrence characteristics and geological origin of typical hazardous elements in low-medium ash coal of Huainan coalfield

With the continuous development, processing and utilization of coal resources in our province, the existence of typical harmful elements in coal is bound to have a negative impact on the efficient and clean utilization of coal resources. Based on the mass data analysis of typical hazardous elements in coal of Huainan coalfield, taking the main coal seams (No.13-1, No.11-2, No.8, No.6, No.4 and No.1) as the research objects, the occurrence characteristics and geological genesis of typical hazardous elements were comprehensively analyzed by the means of ICP-MS, AFS, stepwise chemical extraction and cluster analysis. The results were as follows: ① Typical hazardous elements Cr, Co, Se and Pb in coal of Huainan coalfield are “lightly enriched”, Hg is “highly enriched” and other elements are in “normal range”; ② The high value area of As element content in Huainan coalfield was mainly located in the west of coalfield; the high value region of Hg element was located in the east of coalfield, followed by the west; the remaining eight elements (Cr, Mn, Co, Ni, Se, Cd, Sb and Pb) were all higher in coal of Panji mining area of Huainan coalfield (especially near Pansan coal mine). The late magmatic hydrothermal process in Panji-Zhuji region may be the main reason for the relative enrichment of hazardous elements such as Cr, Mn, Co, Ni, Se, Cd, Sb and Pb. ③ There were many ion-exchange States in the occurrence state of Hg, and the inorganic components brought by magmatic hydrothermal action may have little influence on the enrichment degree of Hg element. The magmatic hydrothermal intrusion in the late diagenesis period had no obvious influence on As, and the low content of As in coal may be related to the low content of As in coal-forming plants

Biomarkers associated with functional improvement after stroke rehabilitation: a systematic review and meta-analysis of randomized controlled trials

ObjectiveThis study aims to identify blood and cerebrospinal fluid biomarkers that are correlated to the functional improvement of stroke patients after rehabilitation therapy, and provide ideas for the treatment and evaluation of stroke patients.MethodsThe PubMed, Web of Science, and Embase databases were searched for articles published in the English language, from inception to December 8, 2022.ResultsA total of 9,810 independent records generated 50 high-quality randomized controlled trials on 119 biomarkers. Among these records, 37 articles were included for the meta-analysis (with a total of 2,567 stroke patients), and 101 peripheral blood and cerebrospinal fluid biomarkers were included for the qualitative analysis. The quantitative analysis results revealed a moderate quality evidence that stroke rehabilitation significantly increased the level of brain-derived neurotrophic factor (BDNF) in serum. Furthermore, the low-quality evidence revealed that stroke rehabilitation significantly increased the concentration of serum noradrenaline (NE), peripheral blood superoxide dismutase (SOD), peripheral blood albumin (ALB), peripheral blood hemoglobin (HB), and peripheral blood catalase (CAT), but significantly decreased the concentration of serum endothelin (ET) and glutamate. In addition, the changes in concentration of these biomarkers were associated with significant improvements in post-stroke function. The serum BNDF suggests that this can be used as a biomarker for non-invasive brain stimulation (NIBS) therapy, and to predict the improvement of stroke patients.ConclusionThe concentration of serum BNDF, NE, ET and glutamate, and peripheral blood SOD, ALB, HB and CAT may suggest the function improvement of stroke patients