2,569 research outputs found

    Numerical Modeling of Geyser Formation by Release of Entrapped Air from Horizontal Pipe into Vertical Shaft

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    Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchive

    Withanolides from Jaborosa caulescens var. bipinnatifida

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    Two new withanolides 2,3-dihydrotrechonolide A (1) and 2,3-dihydro-21-hydroxytrechonolide A (2) were isolated along with two known withanolides trechonolide A (3) and jaborosalactone 39 (4) from Jaborosa caulescens var. bipinnatifida (Solanaceae). The structures of 1-2 were elucidated through 2D NMR and other spectroscopic techniques. In addition, the structure of withanolide 1 was confirmed by X-ray crystallographic analysis

    A breakthrough dynamic-osmotic membrane bioreactor/nanofiltration hybrid system for real municipal wastewater treatment and reuse.

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    This study designed a Dynamic-Osmotic membrane bioreactor/nanofiltration (OsMBR/NF) system for municipal wastewater treatment and reuse. Results indicated that a continuously rotating FO module with 60 RPM in Dynamic-OsMBR system could enhance shear stress and reduce cake layer of foulants, leading to higher flux (50%) compared to Traditional-OsMBR during a 40-operation day. A negligible specific reverse salt flux (0.059 G/L) and a water flux of 2.86 LMH were recorded when a mixture of 0.1Ā M EDTA-2Na/0.1Ā M Na2CO3/0.9Ā mM Triton114 functioned as draw solution (DS). It was found that the Dynamic-OsMBR/NF hybrid system could effectively remove pollutants (āˆ¼98% COD, āˆ¼99% PO43-P, āˆ¼93% NH4+-N, > 99% suspended solids) from wastewater. In short, this developed system can be considered a breakthrough technology as it successfully minimizes membrane fouling by shear force, and achieves high water quality for reuse by two membrane- barriers

    Free vibration analysis of laminated composite plates based on FSDT using one-dimensional IRBFN method

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    This paper presents a new effective radial basis function (RBF) collocation technique for the free vibration analysis of laminated composite plates using the first order shear deformation theory (FSDT). The plates, which can be rectangular or non-rectangular, are simply discretised by means of Cartesian grids. Instead of using conventional differentiated RBF networks, one-dimensional integrated RBF networks (1D-IRBFN) are employed on grid lines to approximate the field variables. A number of examples concerning various thickness-to-span ratios, material properties and boundary conditions are considered. Results obtained are compared with the exact solutions and numerical results by other techniques in the literature to investigate the performance of the proposed method

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

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    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 2019ā€“June 2020), the antibiotic prescribing rate for COVID-19 patients (June 2020ā€“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 ā€œWatchā€ 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

    Distinct magnetic regimes through site-selective atom substitution in the frustrated quantum antiferromagnet Cs2_2CuCl4āˆ’x_{4-x}Brx_x

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    We report on a systematic study of the magnetic properties on single crystals of the solid solution Cs2_2CuCl4āˆ’x_{4-x}Brx_x (0 ā‰¤\leq x ā‰¤\leq 4), which include the two known end-member compounds Cs2_2CuCl4_4 and Cs2_2CuBr4_4, classified as quasi-two-dimensional quantum antiferromagnets with different degrees of magnetic frustration. By comparative measurements of the magnetic susceptibility Ļ‡\chi(TT) on as many as eighteen different Br concentrations, we found that the inplane and out-of-plane magnetic correlations, probed by the position and height of a maximum in the magnetic susceptibility, respectively, do not show a smooth variation with x. Instead three distinct concentration regimes can be identified, which are separated by critical concentrations xc1_{c1} = 1 and xc2_{c2} = 2. This unusual magnetic behavior can be explained by considering the structural peculiarities of the materials, especially the distorted Cu-halide tetrahedra, which support a site-selective replacement of Cl- by Br- ions. Consequently, the critical concentrations xc1_{c1} (xc2_{c2}) mark particularly interesting systems, where one (two) halidesublattice positions are fully occupied.Comment: 15 pages, 4 figure

    The stable phases of the Cs2CuCl4-xBrx mixed systems

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    Starting from Cs2CuCl4 and Cs2CuBr4 our project focuses on the growth of the Cs2CuCl4-xBrx mixed crystals from aqueous solution and the investigation of the occurring structural variations. The well known orthorhombic structure (space group Pnma) of the end members of this system is interrupted within the intermediate composition range Cs2CuCl3Br1 - Cs2CuCl2Br2, if the growth takes place at room temperature. Within this range a new tetragonal phase is found (space group I4/mmm). However, in case the growth temperature will be increased to 50 {\deg}C, the existence of the orthorhombic structure can be extended over the whole Cs2CuCl4-xBrx mixed system. A detailed analysis of the composition dependence of the lattice parameters is used to draw conclusions on the incorporation of Cl- and Br-ions at different sites which is important for the magnetic interactions between the Cu-ions.Comment: 16 pages,8 figure

    Determining 1āˆ’āˆ’1^{--} Heavy Hybrid Masses via QCD Sum Rules

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    The masses of 1āˆ’āˆ’1^{--} charmonium and bottomonium hybrids are evaluated in terms of QCD sum rules. We find that the ground state hybrid in charm sector lies in mHc=4.12āˆ¼4.79m_{H_c}=4.12\sim 4.79 GeV, while in bottom sector the hybrid may situated in mHb=10.24āˆ¼11.15m_{H_b} = 10.24\sim 11.15 GeV. Since the numerical result on charmonium hybrid mass is not compatible with the charmonium spectra, including structures newly observed in experiment, we tempt to conclude that such a hybrid does not purely exist, but rather as an admixture with other states, like glueball and regular quarkonium, in experimental observation. However, our result on bottomonium hybrid coincide with the "exotic structure" recently observed at BELLE.Comment: 15 pages, 5 figures, version to appear in J.Phys.
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