Semi-analytical solution to the second-order wave loads on a vertical cylinder in bi-chromatic bi-directional waves

A complete solution is presented for the second-order wave loads experienced by a 15 uniform vertical cylinder in bi-chromatic bi-directional waves. The solution is obtained 16 based on the introduction of an assisting radiation potential without explicitly 17 evaluating the second-order diffraction potential. The semi-analytical formulation for 18 calculating the wave loads is provided and an efficient numerical technique is 19 developed to treat the oscillatory free-surface integral that appears in the force 20 formulation. After validating the present solution by comparing with the predictions 21 based on other methods, numerical studies are conducted for different combinations of 22 incident wave frequencies and wave headings, and the influence of frequencies and 23 headings of dual waves on the second-order wave loads is investigated. In addition, by 24 expressing the second-order wave loads in a power expansion with respect to the wave 25 frequency difference and wave heading difference which are both assumed to be small, 26 approximations on the calculation of wave loads are developed. The accuracy of 27 different approximations is assessed by comparing the approximate results with those 28 based on the complete solution

Effects of tanshinone on hyperandrogenism and the quality of life in women with polycystic ovary syndrome: protocol of a double-blind, placebo-controlled, randomised trial.

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Simulation Study of Heat Transportation in an Aquifer about Well-water-source Heat Pump

The study of groundwater reinjection, pumping and heat transportation in an aquifer plays an important theoretical role in ensuring the stability of deep-well water reinjection and pumping as well as smooth reinjection. Based on the related conception of underground hydrogeology and the rationale of seepage flow mechanics, a geologic conceptual model of doublet reinjection and a seepage flow model of heat transportation are proposed in this paper. The temperature distribution in the temperature field was obtained by a coupled method of the heat transportation equation and groundwater seepage flow equation fitting for the seepage-affected section. The temperature changes in aquifer and heat storage efficiency are analyzed under different working conditions. All the work referenced above provided references for the popularization and evaluation of well-water source heat pump

Antibiotic Use and Bacterial Infection in COVID-19 Patients in the Second Phase of the SARS-CoV-2 Pandemic: A Scoping Review

This scoping review aimed to explore the prevalence and patterns of global antibiotic use and bacterial infection in COVID-19 patients from studies published between June 2020 and March 2021. This review was reported in line with the Preferred Reporting of Systematic Reviews and Meta-Analyses (PRISMA) extension for Scoping Reviews, and the protocol is registered with the Open Science Framework. Compared with our previously-published review of the period (December 2019–June 2020), the antibiotic prescribing rate for COVID-19 patients (June 2020–March 2021) was found to have declined overall (82.3% vs. 39.7%), for mild and moderate patients (75.1% vs. 15.5%), and for severe and critical patients (75.3% vs. 48.3%). The seven most frequently prescribed antibiotics in COVID-19 patients were all on the “Watch” list of the WHO AWaRe antibiotics classification. The overall reported bacterial infection rate in COVID-19 patients was 10.5%, and the most frequently reported resistant pathogen in COVID-19 patients was Staphylococcus aureus, followed by Pseudomonas aeruginosa, Escherichia coli, and Klebsiella pneumoniae. There is an urgent need to establish comprehensive and consistent guidelines to assist clinicians in selecting appropriate antibiotics for COVID-19 patients when needed. The resistance data on the most frequently used antibiotics for COVID-19 patients for certain resistant pathogens should be closely monitored

Surface grinding of carbon fiber-reinforced plastic composites using rotary ultrasonic machining: Effects of tool variables

Citation: Wang, H., Ning, F. D., Hu, Y. B., Fernando, P., Pei, Z. J., & Cong, W. L. (2016). Surface grinding of carbon fiber-reinforced plastic composites using rotary ultrasonic machining: Effects of tool variables. Advances in Mechanical Engineering, 8(9), 14. doi:10.1177/1687814016670284Carbon fiber-reinforced plastic composites have many superior properties, including low density, high strength-to-weight ratio, and good durability, which make them attractive in many industries. However, due to anisotropic properties, high stiffness, and high abrasiveness of carbon fibers in carbon fiber-reinforced plastic, high cutting force, high tool wear, and high surface roughness are always caused in conventional machining processes. This article reports an investigation using rotary ultrasonic machining in surface grinding of carbon fiber-reinforced plastic composites in order to develop an effective and high-quality surface grinding process. In rotary ultrasonic machining surface grinding of carbon fiber-reinforced plastic composites, tool selection is of great importance since tool variables will significantly affect output variables. In this work, the effects of tool variables, including abrasive size, abrasive concentration, number of slots, and tool end geometry, on machining performances, including the cutting force, torque, and surface roughness, are experimentally studied. The results show that lower cutting forces and torque are generated by the tool with higher abrasive size, lower abrasive concentration, and two slots. Lower surface roughness is generated by the tool with smaller abrasive size, smaller abrasive concentration, two slots, and convex end geometry. This investigation will provide guides for tool selections during rotary ultrasonic machining surface grinding of carbon fiber-reinforced plastic composites

Colossal Elastocaloric Effect in Ferroelastic Ni-Mn-Ti Alloys

Energy-efficient and environment-friendly elastocaloric refrigeration, which is a promising replacement of the conventional vapor-compression refrigeration, requires extraordinary elastocaloric properties. Hitherto the largest elastocaloric effect is obtained in small-size films and wires of the prototype NiTi system. Here, we report a colossal elastocaloric effect, well exceeding that of NiTi alloys, in a class of bulk polycrystalline NiMn-based materials designed with the criterion of simultaneously having large volume change across phase transition and good mechanical properties. The reversible adiabatic temperature change reaches a strikingly high value of 31.5 K and the isothermal entropy change is as large as 45  J kg−1 K−1. The achievement of such a colossal elastocaloric effect in bulk polycrystalline materials should push a significant step forward towards large-scale elastocaloric refrigeration applications. Moreover, our design strategy may inspire the discovery of giant caloric effects in a broad range of ferroelastic materials

Effect of Reducing Atmosphere on the Magnetism of Zn1-xCoxO Nanoparticles

We report the crystal structure and magnetic properties of Zn1-xCoxO nanoparticles synthesized by heating metal acetates in organic solvent. The nanoparticles were crystallized in wurtzite ZnO structure after annealing in air and in a forming gas (Ar95%+H5%). The X-ray diffraction and X-ray photoemission spectroscopy (XPS) data for different Co content show clear evidence for the Co+2 ions in tetrahedral symmetry, indicating the substitution of Co+2 in ZnO lattice. However samples with x=0.08 and higher cobalt content also indicate the presence of Co metal clusters. Only those samples annealed in the reducing atmosphere of the forming gas, and that showed the presence of oxygen vacancies, exhibited ferromagnetism at room temperature. The air annealed samples remained non-magnetic down to 77K. The essential ingredient in achieving room temperature ferromagnetism in these Zn1-xCoxO nanoparticles was found to be the presence of additional carriers generated by the presence of the oxygen vacancies.Comment: 11 pages, 6 figures, submitted to Nanotechnology IO

cDNA cloning and sequence analysis of hepatitis G virus genome isolated from a Chinese blood donor

Objective To obtain full-length sequence of a Chinese hepatitis G virus (HGV) strain (HGVch) and investigate the genetic characteristic of HGVch and its identity to other isolates. Methods Reverse transcription (RT) and nested-PCR were used to screen HGV RNA positive serum and amplify cDNA fragments. A positive serum without known hepatitis virus markers was selected for isolating HGV RNA template. The HGV genome was divided into 12 overlapping fragments and directly cloned into pGEM-T vector. Sequences were determined by dideoxy terminus-end method of DNA sequencing and then analyzed by computer. Results The twelve fragments of HGVch cover 9213 nucleotides in length, containing a large opera reading frame (ORF) encoding 2873 animo acids polyprotein that began with a methonine residue and ended at termination codon. HGVch is about 86.5% - 89.5% identical to other known HGV isolates at the nucleotide level and about 93.9% - 96.2% at the deduced animo acid level. Conclusion HGV is a non-A-E hepatitis causal agent, proved to be related with posttransfusion hepatitis in all over the world. Chinese HGV isolate has very close relationship to other isolates from Africa, Europe, Japan, without significant difference across the entire genome. It is suggested that the sequences of HGV isolates are very conservative and the evolution is very slow

Seroepidemiology of Toxoplasma gondii infection in patients with liver disease in eastern China

The role of the protozoan parasite Toxoplasma gondii in the pathogenesis of liver disease has recently gained much interest. The aim of this study was to determine the prevalence and risk factors associated with T. gondii infection in patients with liver disease from three cities in Shandong and Henan provinces, China. A case–control study was conducted from December 2014 to November 2015 and included 1142 patients with liver disease and 1142 healthy controls. Serum samples were collected from all individuals and were examined with enzyme-linked immunosorbent assay for the presence of anti-T. gondii IgG and IgM antibodies. Information on the demographics, clinical, and lifestyle characteristics of the participants was collected from the medical records and by the use of a questionnaire. The prevalence of anti-T. gondii IgG was 19·7% in patients with liver disease compared with 12·17% in the controls. Only 13 patients had anti-T. gondii IgM antibodies compared with 12 control individuals (1·14% vs. 1·05%, respectively). The highest seroprevalence was detected in patients with liver cancer (22·13%), followed by hepatitis patients (20·86%), liver cirrhosis patients (20·42%), and steatosis patients (20%). Multivariate logistic regression analysis indicated that consumption of raw meat (odds ratio (OR) = 1·32; 95% confidence interval (CI) 1·01–1·71; P = 0·03) and source of drinking water from wells (OR = 1·56; 95% CI 1·08–2·27; P = 0·01) were independent risk factors for T. gondii infection in liver disease patients. These findings indicate that T. gondii infection is more likely to be present in patients with liver disease. Therefore, efforts should be directed toward health education of populations at high risk of T. gondii infection and measures should be taken to protect vulnerable patients with liver disease

P-wave Quarkonium Decays to Meson Pairs

The processes of P-wave Quarkonium exclusive decays to two mesons are investigated, in which the final state vector mesons with various polarizations are considered separately. In the calculation, the initial heavy quarkonia are treated in the framework of non-relativistic quantum chromodynamics, whereas for light mesons, the light cone distribution amplitudes up to twist-3 are employed. It turns out that the higher twist contribution is significant and provides a possible explanation for the observation of the hadron helicity selection rule violated processes $\chi_{c1}\rightarrow \phi\phi,\omega\omega$ by the BESIII collaboration in recently. We also evaluate the $\chi_{b1}\to J/\psi J/\psi$ process and find that its branching ratio is big enough to be measured at the B-factories.Comment: more results and discussions adde