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This paper presents an isogeometric (IGA) solver for steady-state incompressiblemagnetohydrodynamics (MHD). MHD is the study of the behavior of electrically conducting fluidsand can be viewed mathematically as a coupled system: the Navier--Stokes equations (for the fluid)and a reduced form of Maxwell's equations (for the electromagnetic field). A key feature of MHDflow is the potential development of very strong shear, usually in proximity to walls. This resultsin two correlated demands on numerical simulation: the need to represent the geometry and thenear-wall shear accurately. In addition, for both the Navier--Stokes and the Maxwell's equations,appropriate discretizations are required for the problem to be well-posed. IGA analysis is a variant ofthe conventional finite element (FE) method, but utilizing the underlying approximations commonlyused in computer-aided design (CAD) to represent geometry, basis functions, and test functions.As a result, IGA can represent curved shapes such as circles and conic sections exactly using B-splines and nonuniform rational B-splines (NURBS). Furthermore, IGA can obtain much improvedaccuracy in the computed solution, for a given number of degrees of freedom, due to its inherentsmoothness and higher continuity of basis functions when compared with standard FE and finitevolume (FV) methods. To address the issue of well-posedness, a set of stable IGA discretizationsfor the Navier--Stokes and Maxwell's equations is developed and incorporated into the IGA solver.A detailed convergence study is carried out to verify the convergence, accuracy, and performance ofthe IGA scheme for certain benchmark cases.

This paper presents an isogeometric (IGA) solver for time-dependent, incompressible magnetohydrodynamics (MHD). In this paper, a combination of inf-sup stable mixed discretisations is considered to discretise the hydrodynamic pair (i.e. velocity and pressure) and magnetic pair (i.e. magnetic field and magnetic pressure). The one step θ-method is used for the temporal discretisation. Manufactured and analytical solutions are considered to assess convergence, accuracy and performance of the IGA solver. Moreover, benchmark problems involving a MHD flow over an obstacle and MHD flow under non-uniform magnetic field are considered to examine the effect of the magnetic field on the flow behaviour.

This paper aims to quantify the uncertainty in the SAS-SST simulation of a prism bluff-body flow due to varying the higher-wavenumber damping factor ( C s ). Instead of performing the uncertainty quantification on the CFD simulation directly, a surrogate modelling approach is adopted. The mesh sensitivity is first studied and the numerical error due to the mesh is approximated accordingly. The Gaussian processes/Kriging method is used to generate surrogate models for quantities of interest (QoIs). The suitability of the surrogate models is assessed using the leave-one-out cross-validation tests (LOO-CV). The stochastic tests are then performed using the cross-validated surrogate models to quantify the uncertainty of QoIs by varying C s . Four prior probability density functions (such as U 0 , 1 , N 0.5 , 0.1 2 , B e t a 2 , 2 and B e t a 5 , 1.5 ) of C s are considered. It is demonstrated in this study that the uncertainty of a predicted QoI due to varying C s is regionally dependent. The flow statistics in the near wake of the prism body are subject to larger variance due to the uncertainty in C s . The influence of C s rapidly decays as the location moves downstream. The response of different QoIs to the changing C s varies greatly. Therefore, the calibration of C s only using observations of one variable may bias the results. Last but not least, it is important to consider different sources of uncertainties within the numerical model when scrutinising a turbulence model, as ignoring the contributions to the total error may lead to biased conclusions.

Amorphous biodegradable copolyesters have been synthesized using various alicyclic monomers, including 1,4-cyclohexanedimethanol (CHDM), 1,4-cyclohexanediol (CHDO), isosorbide (1,4:3,6-dianhidro-D-sorbitol) (IS), and 1,4-cyclohexane dicaboxylic acid (CHDA), to enhance the thermal properties of polyesters. We have studied the effect of alicyclic monomers on the thermal properties, especially, on the glass transition temperature (T g ) of the amorphous copolyesters. On incorporating alicyclic diol monomers into poly(ethylene succinate-co-terephthalate) (PEST), T g of amorphous copolyesters was greatly increased. As the rigidity of alicyclic monomers increases, the effect becomes more significant. By comparing copolyesters synthesized with the same molar ratio of alicyclic monomers in the feed, we found that the molar ratio of IS in the copolyester product was much smaller than those of CHDM and CHDO. Nonetheless, IS induced the largest T g enhancement in copolyesters even though a much smaller molar ratio of IS was incorporated in the product compared to CHDM and CHDO. To study the effects of alicyclic diacid monomers, copolyesters containing CHDA were synthesized. As in the case of alicyclic diols, CHDA was found to be very effective in enhancing the thermal properties. Among these copolyesters produced, PEI30ST synthesized with 30 mol% of succinic acid (SA) and 70 mol% of dimethyl terephthalate (DMT) as diacid and 30 mol% of IS as diol exhibited the highest T g of 74.2 °C. And poly(ethylene-co-CHDM succinate-co-terephthalate) (PEC30ST70) and poly(ethylene-co-IS succinate-co-terephthalate) (PEI30ST70) exhibited high optical transmittance and were confirmed to be biodegradable, exhibiting about 50% and 40% biodegradability, respectively, after 50 days in a biodegradability test under compost conditions. Hence, these novel transparent biodegradable polyesters could be highly useful in flexible packaging applications requiring transparency.

Background The largest outbreak of Middle East respiratory syndrome coronavirus (MERS-CoV) infection outside Middle East Asia in 2015 has necessitated the rapid expansion of laboratories that conduct MERS-CoV molecular testing in Korea, together with external quality assessment (EQA) to evaluate the assays used. Methods The EQA program consisted of two phases; self-validation and blind assessment. For the first EQA phase, in vitro transcribed upstream region of the envelope gene (upE) and the open reading frame (ORF)1a RNAs were used at a concentration of 1,000 copies/µL. The test panel for the second EQA phase consisted of RNA extracts from three samples, which were obtained from two MERS-CoV positive patients and one MERS-CoV negative patient. Results The first EQA phase results for 46 participants showed a linear relationship between the threshold cycle (CT) values of RNA materials and the logarithmic concentrations for both upE and ORF1a gene targets (R2=0.73 and 0.75, respectively). The mean CT value for each concentration was different depending on which commercial kit was used for the assay. Among the three commonly used kits, PowerChek MERS Real-Time PCR kit (KogeneBiotech, Korea) showed the lowest CT values at all concentrations of upE and most concentrations of ORF1a. The second EQA phase results for 47 participants were 100% correct for all tested samples. Conclusions This EQA survey demonstrates that the MERS-CoV molecular testing performed in Korea during the 2015 outbreak is of robust capability. However, careful establishment and validation of a cut-off value are recommended to ensure good analytical sensitivity.

In this study, RELAP5’s capability to simulate thermal stratification under different conditions is assessed. In nuclear power plants (NPPs), thermal stratification can occur in the following locations: pressurizer, piping systems such as hot legs, cold legs, surge lines, and cooling tanks if available. In general, thermal stratification in a horizontal pipe could not be simulated by RELAP5 due to the inherent one-dimensional setting. Moreover, RELAP5 failed to simulate turbulent penetration which was often a pre-requisite prior to thermal stratification in a pipe. This type of situation could arise in connection between hot leg and surge line, spray lines, feed water lines, etc. It is recommended that for this type of problem CFD be used. In the literature, it was found that RELAP5 was capable of simulating thermal stratification in a pool or a tank-like component if multiple channels and crossflow junctions were used. However, due to uncertainties associated with the input model, the current RELAP5 model failed to reproduce experimental data and therefore further investigation would be required to identify the sources of error.

In the period from September 2012 to April 2017, 1,936 laboratory-confirmed Middle East respiratory syndrome coronavirus (MERS-CoV) cases, including 690 deaths, were reported from 27 countries ( ). Owing to the high virulence of MERS-CoV, there is an

During the 2015 Middle East respiratory syndrome coronavirus outbreak in South Korea, we sequenced full viral genomes of strains isolated from 4 patients early and late during infection. Patients represented at least 4 generations of transmission. We found no evidence of changes in the evolutionary rate and no reason to suspect adaptive changes in viral proteins.

Sodium butyrate (NaBu) is used as a productivity enhancer for the production of therapeutic recombinant proteins in Chinese hamster ovary (CHO) cells. However, NaBu is well-known for having a cytotoxic effect, thereby inducing apoptosis. As an endeavor to reduce this defect, we studied 11 antioxidants known for inhibiting apoptosis, according to a Plackett-Burman statistical design on CHO cells producing recombinant interferon-beta-1a (IFN-beta). None of the antioxidants that we tested were as effective as N-acetylcystein (NAC) from the point of view of maintaining long-term survival of CHO cells and increasing the production of IFN-beta. In 7.5-L perfusion bioreactor cultures, the addition of NaBu and NAC elongated the culture period to almost 200 h throughout production phase and increased the production yield by 2-fold compared to control cultures containing only NaBu. Glycosylation patterns of produced IFN-beta at each run were also compared in IEF analysis. IEF profiles of where NaBu and NAC were added showed to be more isoforms with a lower pI than those of the control run. The sialic acid content was also increased by 17.7% according to HPLC analysis. Taken together, the data obtained demonstrate that the addition of NAC has positive effects on the elongation of the culture period, improving the production and increasing the sialylation of IFN-beta in NaBu-treated CHO cells.