19 results match your criteria: "Institute of Hydromechanics[Affiliation]"

Increased thyroid cancer incidence has been one of the principal adverse health effects of the Chornobyl (Chernobyl) nuclear power plant accident. Accurate dose estimation is critical for assessing the radiation dose-response relationship. Current dosimetry estimates for individuals from the Chornobyl Tissue Bank (CTB) are based only on the limited information on their places of residence at the time of the accident and/or at the time of surgery for thyroid cancer.

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Should we ignore SARS-CoV-2 disease?

Epidemiol Infect

March 2024

Institute of Hydromechanics, National Academy of Sciences of Ukraine, Kyiv, Ukraine.

Current World Health Organization (WHO) reports claim a decline in COVID-19 testing and reporting of new infections. To discuss the consequences of ignoring severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection, the endemic characteristics of the disease in 2023 with the ones estimated before using 2022 data sets are compared. The accumulated numbers of cases and deaths reported to the WHO by the 10 most infected countries and global figures were used to calculate the average daily numbers of cases and deaths per capita and case fatality rates () for two periods in 2023.

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Introduction: The population, governments, and researchers show much less interest in the COVID-19 pandemic. However, many questions still need to be answered: why the much less vaccinated African continent has accumulated 15 times less deaths per capita than Europe? or why in 2023 the global value of the case fatality risk is almost twice higher than in 2022 and the UK figure is four times higher than the global one?

Methods: The averaged daily numbers of cases and death per million, case fatality risks were calculated for 34 countries and regions with the use of John Hopkins University (JHU) datasets. Possible linear and non-linear correlations with the averaged daily numbers of tests per thousand , median age of population A, and percentages of vaccinations and boosters were investigated.

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Technological modeling of physicochemical removal of iron from deep groundwater.

Heliyon

September 2023

Department of Water Supply, Sewerage and Drilling, National University of Water and Environmental Engineering, 11 Soborna Street, Rivne, Ukraine.

In view of the significant difficulties arising in controlling the operation of the rapid iron removal filters on the basis of full exhaustion of their clarifying resource at every calculation stage (filter run), it is suggested to realize a simple control algorithm, which assumes an equal duration of filter runs during the entire service life of one filtering material change. Since the efficiency of physicochemical iron removal depends significantly on the specified duration, in order to establish its optimal value in every given case it is necessary to perform a special technical and economic analysis with a detailed consideration of the composition and degree of contamination of natural water. In the working conditions considered above, which are typical for physicochemical iron removal from deep groundwater in Ukraine, such a value was 600 conventional units, which corresponds to 48 h.

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Endemic characteristics of SARS-CoV-2 infection.

Sci Rep

September 2023

Institute of Hydromechanics, National Academy of Sciences of Ukraine, Kyiv, Ukraine.

The fourth year of the COVID-19 pandemic without decreasing trends in the global numbers of new daily cases, high numbers of circulating SARS-CoV-2 variants and re-infections together with pessimistic predictions for the Omicron wave duration force studies about the endemic stage of the disease. The global trends were illustrated with the use the accumulated numbers of laboratory-confirmed COVID-19 cases and deaths, the percentages of fully vaccinated people and boosters (additional vaccinations), and the results of calculation of the effective reproduction number provided by Johns Hopkins University. A new modified SIR model with re-infections was proposed and analyzed.

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The challenges humanity is facing due to the Covid-19 pandemic require timely and accurate forecasting of the dynamics of various epidemics to minimize the negative consequences for public health and the economy. One can use a variety of well-known and new mathematical models, taking into account a huge number of factors. However, complex models contain a large number of unknown parameters, the values of which must be determined using a limited number of observations, e.

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Groups of bluff bodies are widespread in nature and technology. These are the supports of bridge crossings, high-rise buildings in cities, offshore drilling and wind platforms, algae and vegetation in the seas and rivers, forests and other objects. The flow of air or water around such structures has a complex vortex and jet character and requires significant efforts in the process of scientific research to improve the environmental situation and reduce material and technical costs in the process of operating such structures.

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Experimental research results of hydrodynamic noise of pulsating flow through a bileaflet mechanical mitral valve are presented. The pulsating flow of pure water corresponds to the diastolic mode of the cardiac rhythm heart. The valve was located between the model of the left atrium and the model of the left ventricle of the heart.

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Bicuspid aortic valve (BAV) is the most common congenital cardiac disease and is a foremost risk factor for aortopathies. Despite the genetic basis of BAV and of the associated aortopathies, BAV-related alterations in aortic fluid-dynamics, and particularly in wall shear stresses (WSSs), likely play a role in the progression of aortopathy, and may contribute to its pathogenesis. To test whether WSS may trigger aortopathy, in this study we used 4D Flow sequences of phase-contrast cardiac magnetic resonance imaging (CMR) to quantitatively compare the fluid dynamics in the thoracic aorta of two groups of subjects: (i) five prospectively enrolled young patients with normo-functional BAV and with no aortic dilation and (ii) ten age-matched healthy volunteers.

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Towards the improved quantification of in vivo abnormal wall shear stresses in BAV-affected patients from 4D-flow imaging: Benchmarking and application to real data.

J Biomech

January 2017

Department of Electronics, Information and Bioengineering, Politecnico di Milano, Milano, Italy. Electronic address:

Bicuspid aortic valve (BAV), i.e. the fusion of two aortic valve cusps, is the most frequent congenital cardiac malformation.

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A portable system for auscultation and lung sound analysis has been developed, including the original electronic stethoscope coupled with mobile devices and special algorithms for the automated analysis of pulmonary sound signals. It's planned that the developed system will be used for monitoring of health status of patients with various pulmonary diseases.

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A pilot scale trickling filter with pebble gravel as media and its performance to remove chemical oxygen demand from synthetic brewery wastewater.

J Zhejiang Univ Sci B

October 2013

Faculty of Agricultural and Environmental Sciences, Institute of Hydromechanics and Water Management, University of Rostock, 18055 Rostock, Germany.

Evaluating the performance of a biotrickling filter for the treatment of wastewaters produced by a company manufacturing beer was the aim of this study. A pilot scale trickling filter filled with gravel was used as the experimental biofilter. Pilot scale plant experiments were made to evaluate the performance of the trickling filter aerobic and anaerobic biofilm systems for removal of chemical oxygen demand (COD) and nutrients from synthetic brewery wastewater.

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Stretching and tilting of material lines in turbulence: the effect of strain and vorticity.

Phys Rev E Stat Nonlin Soft Matter Phys

March 2006

Institute of Hydromechanics and Water Resources Management, Swiss Federal Institute of Technology, ETH Honggerberg, CH 8093 Zurich, Switzerland.

The Lagrangian evolution of infinitesimal material lines is investigated experimentally through three dimensional particle tracking velocimetry (3D-PTV) in quasihomogeneous turbulence with the Taylor microscale Reynolds number Re(lambda)=50. Through 3D-PTV we access the full tensor of velocity derivatives du(i)/dx(j) along particle trajectories, which is necessary to monitor the Lagrangian evolution of infinitesimal material lines l. By integrating the effect on l of (i) the tensor du(i)/dx(j), (ii) its symmetric part s(ij), (iii) its antisymmetric part r(ij), along particle trajectories, we study the evolution of three sets of material lines driven by a genuine turbulent flow, by "strain only," or by "vorticity only," respectively.

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A method is proposed to estimate the uncertainty of the location of pathlines in two-dimensional, steady-state confined or unconfined flow in aquifers due to the uncertainty of the spatially variable unconditional hydraulic conductivity or transmissivity field. The method is based on concepts of the semianalytical first-order theory given in Stauffer et al. (2002, 2004), which allows estimates of the lateral second moment (variance) of the location of a moving particle.

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Nuclear magnetic resonance imaging (NMRI) methods for visualization of fluid flow and transport in porous media are reviewed in this paper. They are illustrated with experiments showing applications of velocity imaging, NMRI measurements of multiphase flow, and NMRI measurements of density flow. The latter two are compared with numerical simulations.

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Transport of a decay chain in homogenous porous media: analytical solutions.

J Contam Hydrol

June 2001

Institute of Hydromechanics and Water Resources Management (IHW), Swiss Federal Institute of Technology (ETH), Zürich, Switzerland.

With the aid of integral transforms, analytical solutions for the transport of a decay chain in homogenous porous media are derived. Unidirectional steady-state flow and radial steady-state flow in single and multiple porosity media are considered. At least in Laplace domain, all solutions can be written in closed analytical formulae.

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Flocs in Shear and Strain Flows.

J Colloid Interface Sci

May 2000

Institute of Hydromechanics and Water Resources Management, Swiss Federal Institute of Technology, Zürich, CH-8093, Switzerland

Preflocculated ferric hydroxide flocs were subjected to either a simple shear flow or a two-dimensional straining flow, and their motion was optically observed. Digital image analysis was applied to extract information on orientation and deformation from the digitized frames. It was found that the simple shear flow led to a rotation of the flocs whose motion can be understood from the behavior of a solid ellipsoid.

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The effects of vessel joint where the both sides have different wall properties on the heart pulse propagation are investigated. Such a local disturbance can influence post-transplantation pathology and evolution of the organ inconsistency. Using a mathematical model, developed in a previous article, we perform analytical analysis and present some qualitative and quantitative estimations.

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