Cavitating propeller flows predicted by RANS solver with structured grid and small reynolds number turbulence model approach

Within the EU research project VIRTUE, a propeller is investigated in uniform and nonuniform inflow conditions by means of a RANS equation solver, FINFLO. The analyses are made in wetted and cavitating conditions. The propeller analyzed in this paper is the INSEAN E779A propeller. The paper contains calculations at three different grid resolutions in wetted conditions and at the two finest grid resolutions in cavitating conditions in uniform inflow. The mediumsize grid is used for the propeller in nonuniform inflow simulations. The simulations are conducted on a model scale and the results are compared with the measurements and cavitation tests performed by INSEAN. The nonuniform inflow is generated by modeling the geometry of the artificial wake generator used in the cavitation tests in the calculation domain. The experimental results are published in several papers, for example in [1] and [2]. The predicted propeller open water thrust and torque are found to be within 5 % of the measured ones. The pressure peak at the leading edge of a blade is found to be sensitive to the grid resolution. The predicted cavitation behavior of the propeller blades is in reasonable accordance with the cavitation test observations. In uniform inflow the vaporized region is overpredicted. Contrastingly, the vaporized region is Underpredicted in the nonuniform inflow calculations. Side entrant jets could be identified in the cavity region in the nonuniform inflow simulations. The predicted vaporized regions in several blade positions together with photographs of the cavitating propeller are shown for comparison. The cavitation behavior trends seemed to be similar in the simulations and observations in nonuniform inflow, except that the rollup of detached sheet cavitation into a tip vortex could not be captured in the calculations. The total wake is measured between the propeller plane and the wake generator. The predicted wake is found to be too strong, but the width of the wake is relatively close to the measurements. The propeller loading history is shown over one propeller revolution. It shows qualitatively reasonable trends. The loading histories of the wetted and cavitating propeller are almost the same due to the relative small cavitating region in the investigated conditions. The pressure distributions at several blade positions on the suction side of the propeller are shown in wetted and cavitating conditions for comparison.http://deepblue.lib.umich.edu/bitstream/2027.42/84244/1/CAV2009-final45.pd

Calculating the 3D magnetic field of ITER for European TBM studies

The magnetic perturbation due to the ferromagnetic test blanket modules (TBMs) may deteriorate fast ion confinement in ITER. This effect must be quantified by numerical studies in 3D. We have implemented a combined finite element method (FEM) -- Biot-Savart law integrator method (BSLIM) to calculate the ITER 3D magnetic field and vector potential in detail. Unavoidable geometry simplifications changed the mass of the TBMs and ferritic inserts (FIs) up to 26%. This has been compensated for by modifying the nonlinear ferromagnetic material properties accordingly. Despite the simplifications, the computation geometry and the calculated fields are highly detailed. The combination of careful FEM mesh design and using BSLIM enables the use of the fields unsmoothed for particle orbit-following simulations. The magnetic field was found to agree with earlier calculations and revealed finer details. The vector potential is intended to serve as input for plasma shielding calculations.Comment: In proceedings of the 28th Symposium on Fusion Technolog

The H-1 and C-13 chemical shifts of 5-5 lignin model dimers : An evaluation of DFT functionals

The calculations of H-1 and C-13 NMR chemical shifts were performed on three 5-5 lignin dimers, prominent substructures in softwood lignins, to compare with experimental data. Initially, 10 DFT functionals (B3LYP, B3PW91, BPV86, CAM-B3LYP, HCTH, HSEH1PBE, mPW1PW91, PBEPBE, TPSSTPSS, and omega B97XD) combined with the gage-including atomic orbital (GIAO) method and basic set 6-31G(d,p) were tested on 3,3'-(6,6'-dihydroxy-5,5'-dimethoxy-[1,1'-biphenyl]-3,3'-diyl)dipropionic acid (1), efficiently synthesized from ferulic acid. HSEH1PBE, mPW1PW91, and omega B97XD were found to be the three best performing functionals with strong correlations (r(2) >= 0.9988) and low errors (CMAEsPeer reviewe

Decomposition products of oxygen scavengers and their effect on corrosion of steam generator materials – I. Diethyl-hydroxylamine and carbohydrazide

Hydrazine used as oxygen scavenger in the secondary circuit of pressurized water reactors is hazardous to the environment and potentially carcinogenic, thus, suitable replacement chemicals for it are actively sought. In the present paper, decomposition products of two potential replacements – carbohydrazide and diethyl-hydroxylamine – are analyzed, and their effect on secondary water chemistry and corrosion of the main steam generator materials – carbon steel 22 K, stainless steel 0X18H10T and Alloy 690 – is studied by in-situ electrochemical techniques complemented by ex-situ analyses of the formed oxides by spectroscopic and microscopic methods. Quantitative interpretation of the electrochemical impedance data with the Mixed-Conduction Model allowed for the estimation of oxidation and corrosion release rates depending on scavenger formulation, alloy type and temperature. Conclusions on the extent of interaction of decomposition products with construction materials are drawn based on the experimental and calculational results.<br/

Progressive Multifocal Leukoencephalopathy: Current Insights

Cases of PML should be evaluated according to predisposing factors, as these subgroups differ by incidence rate, clinical course, and prognosis. The three most significant groups at risk of PML are patients with hematological malignancies mostly previously treated with immunotherapies but also untreated, patients with HIV infection, and patients using monoclonal antibody (mAb) treatments. Epidemiological data is scarce and partly conflicting, but the distribution of the subgroups appears to have changed. While there is no specific anti-JCPyV treatment, restoration of the immune function is the most effective approach to PML treatment. Research is warranted to determine whether immune checkpoint inhibitors could benefit certain PML subgroups. There are no systematic national or international records of PML diagnoses or a risk stratification algorithm, except for MS patients receiving natalizumab (NTZ). These are needed to improve PML risk assessment and to tailor better prevention strategies.Peer reviewe

ESTIMATION OF H-p(3) AMONG STAFF MEMBERS IN TWO NUCLEAR MEDICINE UNITS IN FINLAND

The eye lens exposure among 16 technicians in two nuclear medicine departments at university hospitals in Finland was investigated by measuring the operational quantity H-p(3) using EYE-D dosemeters. For all workers, the annual mean H-p(3) was estimated to be 1.1 mSv (max. 3.9 mSv). The relation between H-p(3) to routinely monitored personal dose equivalent H-p(10) was clearly correlated. Considering individual dose measurement periods (2-4 weeks), the H-p(3)/H-p(10) ratio was 0.7 (Pearson's coefficient r = 0.90, p 0.1 mSv vs. <0.1 mSv, respectively), i.e. higher Hp(10) predicts H-p(3) more reliably. Moreover, annual H-p(10) data from national dose register during 2009-2018 were used to derive the annual H-p(3) applying the H-p(3)/H-p(10) ratio. The data from Finnish nuclear medicine departments imply that routine measurements of H-p(3) among nuclear medicine technicians are not justified.Peer reviewe