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One of the most important issues in multi-criteria decision making is the number of requited judgments decision-maker/analyst has to perform. This paper presents a comparison of the results obtained by standard analytic hierarchy process (AHP), limited AHP, and best-worst method (BWM) if the number of criteria is 6, 7, and 8. The examples show that BWM's results are comparable with the results if standard AHP is used, while the limited version of AHP is generally inferior to the other two methods.

Background The presence of a left ventricular thrombus (LVT) poses a risk of thromboembolic complications and excludes patients from undergoing left ventricular assist device (LVAD) implantation without the aid of cardiopulmonary bypass (CPB). Transthoracic echocardiography (TTE) and transesophageal echocardiography are used to detect LVT in patients with heart disease; however, the detection validity of these imaging studies has not been definitively elucidated. Methods A retrospective analysis of patients with end-stage heart failure who underwent LVAD implantation from May 2012 to August 2018 in a single center was completed. To be included, patients’ medical records had to have presurgical TTE and transesophageal echocardiographic images, as well as intraoperative digital and visual exploration observations. A total of 301 patients underwent LVAD implantation; 239 of these patients had an LVAD implanted with the use of CPB. A total of 230 patients had complete data sets and were included in the analysis. Results Preoperative TTE identified LVT in 23 of the 230 patients (10%); 15 patients (6.5%) had LVT confirmed by surgical intraventricular visualization. Of the patients with visual LVT confirmation, preoperative TTE identified an LVT in all but 1 case (93%; 14 of 15). Preoperative TTE of LVT had a high sensitivity (94%) and specificity (96%), as well as high negative predictive value (99%). Conclusions The results of this study show that preoperative TTE is highly accurate for LVT detection. The high negative predictive value could have significant implications for the choice of surgical procedure because with TTE, surgeons can reasonably determine whether LVAD placement procedure can be attempted without CPB support.

This paper reviews the current status of boiling heat transfer modelling, discusses the need for its improvement due to unresolved intriguing experimental findings and emergence of novel technical applications and outlines the directions for an advanced modelling approach. The state-of-the-art of computational boiling heat transfer studies is given for: macro-scale boiling models applied in two-fluid liquid-vapour interpenetrating media approach, micro-, meso-scale boiling computations by interface capturing methods, and nano-scale boiling simulations by molecular dynamics tools. Advantages, limitations and shortcomings of each approach, which originate from its grounding formulations, are discussed and illustrated on results obtained by the boiling model developed in our research group. Based on these issues, we stress the importance of adaptation of a multi-scale approach for development of an advanced boiling predictive methodology. A general road-map is outlined for achieving this challenging goal, which should include: improvement of existing methods for computation of boiling on different scales and development of conceptually new algorithms for linking of individual scale methods. As dramatically different time steps of integration for different boiling scales hinder the application of full multi-scale methodology on boiling problems of practical significance, we emphasise the importance of development of another algorithm for the determination of sub-domains within a macro-scale boiling region, which are relevant for conductance of small-scale simulations.

In this paper the dynamics of explosive boiling of a 72 A thick water film on the hot copper substrate with the plain surface is analysed. The analyses are based on the results of molecular dynamics (MD) simulations of the transient in which the thermostat temperature within the solid substrate is increased from 298 to 800K. The obtained results show that explosive boiling comprises several phases. The first phase involves rapid thermoacoustic pressure build-up in the near wall region due to intensive water heating and its volumetric expansion. The generated compression wave propagates through the liquid film reaching the peak value higher than critical water pressure. Due to reflection at the free film surface the original compression wave turns into an expansion wave. This event leads to a rapid pressure decrease and occurrence of tension stress. The second phase starts when the pressure enters the negative domain. This phase is accompanied with nucleation of vapour embryos and their subsequent growth in the superheated water layer in the near wall region. As the intensity of vapour phase generation is moderate, the liquid film in this phase is still exposed to tension. The stress recovery starts in the third phase when the water temperature in the near wall layer attains the spinodal value. This leads to a massive vaporization, nanobubble coalescence and thermal explosion, which causes spallation of the liquid film and lift-off of the liquid slug. The last phase is characterized by suppression of heat transfer by the expanding vapour layer. As a consequence, after reaching the maximum, the pressure decreases. This paper gives quantitative description and detailed insight into the mechanisms associated with each of the aforementioned phases.

Myocarditis continues to present challenges in diagnosis and management. The goal of this study is to determine the occurrence and manifestations of myocarditis in a heart failure (HF) population. The analyzed patients had acute or persistent HF and were referred over a 6-year period to a quaternary HF center for advanced HF therapies including mechanical circulatory support, left ventricular assist device (LVAD) implantation, and/or heart transplantation. The histopathological diagnosis of myocarditis was made based on the presence of an inflammatory infiltrate of the myocardium, typically with associated cardiomyocyte (CMC) damage, combined as indicated with immunohistochemical and molecular biology characterization. The pathological findings were correlated with a panel of clinical parameters and clinical course of the patients. Myocarditis was identified in 36 patients, with initial diagnoses made in 10 (40%) of 25 by endomyocardial biopsy (EMB), 1 by atrial biopsy (maze procedure), 7 (2.1%) of 331 at LVAD implantation, and 18 (7.8%) of 229 in the explanted heart. There were 20 cases of lymphocytic myocarditis, 4 cases of giant cell myocarditis, 3 cases of eosinophilic myocarditis, and 9 cases of lymphohistocytic with granulomas myocarditis - cardiac sarcoidosis. EMB was performed in 25 patients and was positive in 10 (40%) of cases. Myocarditis was found in 23 explanted hearts including 18 cases de novo and 5 cases with a previously positive specimen. Of the 23 explanted hearts, 21 were nonischemic cardiomyopathy and 2 were ischemic cardiomyopathy. Our findings show that, in patients presenting to a quaternary medical center, myocarditis can be manifest as acute HF as well as a complicating factor in chronic HF.

This work presents numerical results for the second-order sensitivities of the temperature distributions in a paradigm benchmark problem modeling heat transport in a reactor fuel rod and the surrounding coolant channel. The development of this benchmark problem was originally motivated by the need to verify the numerical results for the first-order sensitivities produced by the FLUENT Adjoint Solver for the G4M Reactor preconceptual design and for a test section designed to investigate thermal-hydraulic phenomena of importance to the safety considerations for this reactor. The relative sensitivities computed using the FLUENT Adjoint Solver had significantly large values, of order unity, thereby motivating the need to investigate the impact of nonlinearities, the bulk of which are quantified by the responses’ second-order sensitivities. However, the current FLUENT Adjoint Solver cannot compute second-order sensitivities, which in turn motivated the derivation of these sensitivities for the heat tra...

This work presents a heat transport benchmark problem when modeling the steady-state radial conduction in a fuel rod coupled to the axial heat convection in a coolant surrounding the rod and flowin...

In modern laboratory medicine there is a growing tendency for finding out the most specific and most sensitive biomarkers as indicators of a disease and diagnostic means for the follow-up treatment and therapeutical results. Detection of sensitive biomarkers was speeded up by world companies as manufacturers of diagnostic reagents. Today, the determination of some biochemical parameters is performed by immunodetermination which uses monoclonal antibodies and different markers, and thus achieving the desired high specificity of determination. The selections of biomarkers which are the most important for the clinical practice and which will give the best diagnostic information, requires large researches including analytical clinical and economic properties. Thanks to statistical methods, especially to ROC analysis, the so-called cutoff-values are determined. On the basis of these values differentiation between sick people and healthy individuals is possible. In other words, the evaluation of clinical specificity requires also inclusion of patients whose clinical picture reflects the disease for which a marker is tested. The development and choice of biomarkers is also helped by IFCC with suggestion of the best procedures and preparation of reference materials. The use of selected biomarkers must be profitable in respect of the price and diagnostic information. In the paper the principles of selection, use diagnostic and prognostic significance of biomarkers is discussed. The following biomarkers served as examples: cardiovascular (troponin T and I myoglobin, CK-MB mass), bone (deoxypyridinolin, osteocalcin, Cterminal propeptide collagen, type I, osteo-alkaline-phosphase), malignant (PSA) and for pancreas diseases (lipase, PAM).

In this paper the investigation of bubble-induced turbulence using direct numerical simulation (DNS) of bubbly two-phase flow is reported. DNS computations are performed for a bubble-driven liquid motion induced by a regular train of ellipsoidal bubbles rising through an initially stagnant liquid within a plane vertical channel. DNS data are used to evaluate balance terms in the balance equation for the liquid phase turbulence kinetic energy. The evaluation comprises single-phase-like terms (diffusion, dissipation and production) as well as the interfacial term. Special emphasis is placed on the procedure for evaluation of interfacial quantities. Quantitative analysis of the balance equation for the liquid phase turbulence kinetic energy shows the importance of the interfacial term which is the only source term. The DNS results are further used to validate closure assumptions employed in modelling of the liquid phase turbulence kinetic energy transport in gas-liquid bubbly flows. In this context, the perf...

Thermal power plants are forced to operate under frequent load changes in energy systems with increased share of solar and wind power plants. These load changes increase thermal power plant aging and reduce their efficiency. Therefore, solutions for energy storage are sought in order to accumulate energy in periods of lower power demand and produce excess power in periods of increased demands. In the present paper the steam accumulator as the thermal energy storage device is applied in a 650 MWe coal-fired thermal power plant to increase its flexibility under the demand for the variable load changes. The steam accumulator is charged during periods of lower power demand, as during the night hours, and discharged during peak load demands. The steam accumulator with volume of 600 m3 is charged with superheated steam (pressure 4.5 MPa and temperature 335 °C) extracted from the exit of high pressure steam turbine. The steam discharged from the steam accumulator replaces the turbine steam extraction for two low pressure heaters: a 59.5 MWt and a 54.6 MWt heater operating at 0.56 MPa and 0.23 MPa steam pressure. This replacement results in an increase of the steam flow rate through the turbine and the turbine power gain of 27.3 MWe during 27 min and 11.5 MWe for additional 13 min. The proposed solution of the steam accumulator installation in the power plant is a new design. The upgrade of power plant flexibility by steam accumulator is demonstrated.