Cogeneration power plants have already been operated in the Czech Republic for several decades. These cogeneration power plants have been mostly operated with original technologies. However, these ...original technologies have to be continuously innovated during the entire operation time. This paper is focused on one of the possible innovations, which could lead to better sustainability and improved flexibility of the cogeneration power plants. Backpressure turbines are still used in many cogeneration power plants. However, backpressure turbines are currently losing suitability for cogeneration power plants, because they always need sufficient heat demand for optimal operation. Backpressure turbines rapidly lose efficiency when facing a lack of heat demand, i.e., mostly in summer season. Currently, condensing turbines are a preferable option for cogeneration power plants, which generally achieve less effective operation, as condensing turbines are able to operate with optional heat demand. Therefore, backpressure turbines are often replaced by condensing turbines with regulated outputs. In spite of the current trend, this article will present an innovative topology, which retains the original backpressure turbine with the addition of the organic Rankine cycle for residual energy utilization.
This paper deals with the options how to model of the Bathtub Curve and how to properly estimate failure intensity during operation time of a system. Firstly, the term "Bathtub Curve" is described. ...The main part is connected with the demonstration of three possible models how to correctly estimate the failure intensity during operation of a system. The main aim of this paper is to assess usefulness of all investigated models for the estimation of failure intensities.
This paper is focused on the usage of the organic Rankine cycles in the current and the new proposed electric power plants. Firstly, the current situation of the usage of these cycles is mentioned. ...In the next part, the motivation of the utilization, advantages and disadvantages of these cycles are described. Then these cycles are divided by the different working fluids. Further, the modeling of the cycles and an investigation of the consequent impact is performed. It is crucial to determine the convenient working fluid and the optimal design of the structure of the whole cycle during proposal of the cycle. The principle of these cycles has been well known for many decades. Currently, there are several situations where the cycles can be used. Moreover, the cycles can be more effective way of the utilization of the heat sources with lower temperature than the classic thermal cycles.
the paper concerns the creation of the analysis of the unplanned shutdowns and estimation of reliability. This analysis is based on the document of all unplanned shutdowns for both units in the Czech ...nuclear power plant Temelin. This investigation is mainly focused on failures of some components, which have significant impact of the decrease of electrical power during operation of the power plant. Thanks to this analysis, we are able to perform the estimation of reliability of the power plant. The estimation is created in Dymola software and gives us certain information of the failures of key components, which must be solved in the future. The determination of the key components is very important step for the modeling of reliability of this power plant.
Veno-arterial extracorporeal membrane oxygenation (VA-ECMO) is increasingly being used for circulatory support in patients with cardiogenic shock, although the evidence supporting its use in this ...context remains insufficient. The ECMO-CS trial (Extracorporeal Membrane Oxygenation in the Therapy of Cardiogenic Shock) aimed to compare immediate implementation of VA-ECMO versus an initially conservative therapy (allowing downstream use of VA-ECMO) in patients with rapidly deteriorating or severe cardiogenic shock.
This multicenter, randomized, investigator-initiated, academic clinical trial included patients with either rapidly deteriorating or severe cardiogenic shock. Patients were randomly assigned to immediate VA-ECMO or no immediate VA-ECMO. Other diagnostic and therapeutic procedures were performed as per current standards of care. In the early conservative group, VA-ECMO could be used downstream in case of worsening hemodynamic status. The primary end point was the composite of death from any cause, resuscitated circulatory arrest, and implementation of another mechanical circulatory support device at 30 days.
A total of 122 patients were randomized; after excluding 5 patients because of the absence of informed consent, 117 subjects were included in the analysis, of whom 58 were randomized to immediate VA-ECMO and 59 to no immediate VA-ECMO. The composite primary end point occurred in 37 (63.8%) and 42 (71.2%) patients in the immediate VA-ECMO and the no early VA-ECMO groups, respectively (hazard ratio, 0.72 95% CI, 0.46-1.12;
=0.21). VA-ECMO was used in 23 (39%) of no early VA-ECMO patients. The 30-day incidence of resuscitated cardiac arrest (10.3.% versus 13.6%; risk difference, -3.2 95% CI, -15.0 to 8.5), all-cause mortality (50.0% versus 47.5%; risk difference, 2.5 95% CI, -15.6 to 20.7), serious adverse events (60.3% versus 61.0%; risk difference, -0.7 95% CI, -18.4 to 17.0), sepsis, pneumonia, stroke, leg ischemia, and bleeding was not statistically different between the immediate VA-ECMO and the no immediate VA-ECMO groups.
Immediate implementation of VA-ECMO in patients with rapidly deteriorating or severe cardiogenic shock did not improve clinical outcomes compared with an early conservative strategy that permitted downstream use of VA-ECMO in case of worsening hemodynamic status.
URL: https://www.
gov; Unique identifier: NCT02301819.
Aims Among patients with cardiogenic shock, immediate initiation of extracorporeal membrane oxygenation (ECMO) did not demonstrate any benefit at 30 days. The present study evaluated 1‐year clinical ...outcomes of the Extracorporeal Membrane Oxygenation in the therapy of Cardiogenic Shock (ECMO‐CS) trial. Methods and results The ECMO‐CS trial randomized 117 patients with severe or rapidly progressing cardiogenic shock to immediate initiation of ECMO or early conservative strategy. The primary endpoint for this analysis was 1‐year all‐cause mortality. Secondary endpoints included a composite of death, resuscitated cardiac arrest or implantation of another mechanical circulatory support device, duration of mechanical ventilation, and the length of intensive care unit (ICU) and hospital stays. In addition, an unplanned post‐hoc subgroup analysis was performed. At 1 year, all‐cause death occurred in 40 of 58 (69.0%) patients in the ECMO arm and in 40 of 59 (67.8%) in the early conservative arm (hazard ratio HR 1.02, 95% confidence interval CI 0.66–1.58; p = 0.93). The composite endpoint occurred in 43 (74.1%) patients in the ECMO group and in 47 (79.7%) patients in the early conservative group (HR 0.83, 95% CI 0.55–1.25; p = 0.29). The durations of mechanical ventilation, ICU stay and hospital stay were comparable between groups. Significant interaction with treatment strategy and 1‐year mortality was observed in subgroups according to baseline mean arterial pressure (MAP) indicating lower mortality in the subgroup with low baseline MAP (<63 mmHg: HR 0.58, 95% CI 0.29–1.16; p interaction = 0.017). Conclusions Among patients with severe or rapidly progressing cardiogenic shock, immediate initiation of ECMO did not improve clinical outcomes at 1 year compared to the early conservative strategy. However, immediate ECMO initiation might be beneficial in patients with advanced haemodynamic compromise.
Aims
Extracorporeal membrane oxygenation (ECMO) in veno‐arterial configuration represents an increasingly used method for circulatory support. ECMO in cardiogenic shock offers rapid improvement of ...circulatory status and significant increase in tissue perfusion. Current evidence on the use of ECMO in cardiogenic shock remains insufficient. The aim of the ECMO‐CS trial is to compare two recognized therapeutic approaches in the management of severe cardiogenic shock: early conservative therapy and early implantation of veno‐arterial ECMO on the background of standard care.
Methods
Eligible patients have either rapidly deteriorating or severe cardiogenic shock, defined using echocardiography, hemodynamic and metabolic criteria. Patients are randomized to the one of two arms: immediate veno‐arterial ECMO therapy or early conservative therapy. All other diagnostic and therapeutic procedures are performed as per current standard of care, including other cardiovascular interventions (i.e. percutaneous coronary intervention or cardiac surgery). Follow‐up includes visits at 30 days, 6 months and 12 months. Primary endpoint is a composite of death from any cause, resuscitated circulatory arrest, and implantation of another mechanical circulatory support device at 30 days. The sample size of 120 individuals (60 in each arm) provides 80% power to detect 50% reduction of primary endpoint, at alpha = 0.05. Patient recruitment started in October 2014.
Conclusion
The results of the ECMO‐CS trial may significantly influence current practice in the management of patients with severe and rapidly deteriorating cardiogenic shock. ECMO‐CS trial registration number is NCT02301819.
This paper deals with a method for low cost power electronic substratescreation, which are used for power electronic devices. Direct bond copper (DBC) technology is suitable for creating substrates ...with excellent thermal and electrical conductivity and good mechanical properties. Furthermore, DBC allows to create copper layers with the thickness of hundreds micrometers in one processing step. In this work, the muffle furnace is used for bonding copper to ceramic. Temperature profile, oxygen concentration during the bonding process and final treatment is described. The last part summarizes the results and presents advantages of this method.
Polymeric bile acid sequestrants (BAS) have recently attracted much attention as lipid-lowering agents. These non-absorbable materials specifically bind bile acids (BAs) in the intestine, preventing ...bile acid (BA) reabsorption into the blood through enterohepatic circulation. Therefore, it is important to understand the structure-property relationships between the polymer sequestrant and its ability to bind specific BAs molecules. In this review, we describe pleiotropic effects of bile acids, and we focus on BAS with various molecular architectures that result in different mechanisms of BA sequestration. Here, we present 1) amphiphilic polymers based on poly(meth)acrylates, poly(meth)acrylamides, polyalkylamines and polyallylamines containing quaternary ammonium groups, 2) cyclodextrins, and 3) BAS prepared via molecular imprinting methods. The synthetic approaches leading to individual BAS preparation, as well as results of their in vitro BA binding activities and in vivo lipid-lowering activities, are discussed.
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•Polymeric bile acid sequestrants specifically bind bile acids and prevent their reabsorption into enterohepatic circulation.•Bile acid sequestrants, in addition to their cholesterol-lowering action, have pleiotropic metabolic effects.•Polymers with covalently bonded quaternary ammonium salts, cyclodextrins and molecularly imprinted sequestrants are discussed.
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