CFD (Computational Fluid Dynamics) computations are carried out in order to investigate the flow distribution and its influence on the heat transfer processes in the high-performance heat exchanger. The subject of this investigation is the classical model of the high-performance heat exchanger with elliptical tubes and rectangular fins. It is possible to find the flow domains where the heat transfer conditions are impaired due to the fully developed turbulent flow. Therefore, the considerable thermal loads occur that may cause the breakdown of the heat exchanger. The emphasis of this investigation is put on the zones and the locations where the tubes are not properly fed with liquid, that result in occurrence of cavitation.

B a c k g r o u n d: Heart failure (HF) is a life-threatening condition which aff ects up to 2% of contemporary populations. Generally, it is a chronic and progressive disease, however in many cases it can be prevented or treated. Nevertheless, effective control of this disease requires awareness of symptoms in the society.

A i m s: The aim of the study was to assess the level of HF knowledge in the Polish population.

M e t h o d s: The questionnaire concerning knowledge about HF prepared by the Competence Network HF under the patronage of the European Heart Failure Association of the ESC, was used. The survey included 534 contributors who formed three groups: medical students — in vast majority at fi rst half of the study course (MS) — 198 (37.1%), HF Awareness Day participants (HFDP) — 134 (25.1%) and other (OP) — 202 (37.8%).

R e s u l t s: Study groups diff ered in terms of gender, age and level of education. As predicted, MS achieved the highest score (22.5 [20.0–24.0]), compared to HFDP (20.0 [17.0–22.0], P <0.001) and OP (19.0 [16.0– 21.0], P <0.001). Knowledge on typical HF symptoms was alarmingly low in the analyzed groups — dyspnea (MS — 96.0%, HFDP — 78.4%, OP — 74.6%), ankle edema (MS — 79.8%, HFDP — 50.6%, OP — 32.2%), body weight gain (MS — 14.1%, HFDP — 17.2%, OP — 4.5%). By multivariate model medical education (β 3.372, 95% CI 2.738–4.005) and own illness or having relatives or friends with HF (β 0.654, 95% CI 0.066–1.242) independently aff ected the score of awareness questionnaire.

C on c l u s i o n s: The basic knowledge on HF in Poland is not sufficient. It is moderately better among MS. Further campaigns improving HF awareness are necessary.

Congestive heart failure (CHF) is the fi nal stage in several heart diseases. The diagnosis of CHF in older patients is a challenge. Preserved left ventricular systolic function is a characteristic type of CHF in seniors. The purpose of the study was to characterize elderly patients with CHF and to highlight specific features of the conditions in seniors. The most common etiology of HF in this group of patients is hypertension and coronary heart disease. In seniors atypical presentations of chronic heart failure is much more common than in younger patients. Malnutrition, limitations of exercise and sedentary lifestyles or comorbid diseases have an influence on asymptomatic, early stage of HF. Th ere are better outcomes of treatment in obese individuals. It is called the obesity paradox. Open communication with a patient and his/her family may improve their response to therapy. When heart failure becomes an incurable disease and aggressive treatment is ineffective, palliative care should be considered in end-of-life heart failure patients. The goal of treatment in the remaining moments of life last moments of life should be maximizing the patient’s comfort.

Numerical analysis of the tensioning cables anchorage zone of a bridge superstructure is presented in this paper. It aims to identify why severe concrete cracking occurs during the tensioning process in the vicinity of anchor heads. In order to simulate the tensioning, among others, a so-called local numerical model of a section of the bridge superstructure was created in the Abaqus Finite Element Method (FEM) environment. The model contains all the important elements of the analyzed section of the concrete bridge superstructure, namely concrete, reinforcement and the anchoring system. FEM analyses are performed with the inclusion of both material and geometric nonlinearities. Concrete Damage Plasticity (CDP) constitutive relation from Abaqus is used to describe nonlinear concrete behaviour, which enables analysis of concrete damage and crack propagation. These numerical FEM results are then compared with actual crack patterns, which have been spotted and inventoried at the bridge construction site.

The protection of Polish architectural heritage in the former eastern borderlands, accomplished through the conservation and technical securing of historical structures, constitutes one of the main programmes that are implemented by the Ministry of Culture and National Heritage. Currently, many Polish historical buildings in the former eastern borderlands are in a very bad technical condition. The load-bearing systems of these elements, as well as elements of their finish, require immediate emergency securing work. The basic steps that precede conservation work are emergency structural works, which guarantee the durability and stability of the entire historical substance. The specifics and complexity of the problem of the failure of historical buildings often demands an in-depth analysis of a series of factors that are difficult to measure and which are responsible for the cause and effect relationship during the early stage of the technical evaluation of a structure. The analyses of failures of numerous historical structures, for instance that were carried out by the authors, have become the inspiration for the search for effective methods of analysis that would allow for an in-depth analysis of the causes and effects of the failures in question. The DEMATEL method (Decision Making Trial and Evaluation Laboratory) that has been presented in this work, and its fuzzy extension, has lately become one of the more popular methods used in the cause-and-effect analysis of various phenomena. The authors demonstrated how this method works on the example of the evaluation and securing of the load-bearing system of the XVII Collegiate church of the Holy Trinity in the town of Olykha in the Volhynskiy Oblast, Ukraine.

Mitral regurgitation is the second most common valvular disease. The etiology is either primary or functional-secondary to the left ventricle dysfunction in the course of coronary artery disease, arterial hypertension and diabetes. Along with the population aging and increasing number of comorbidities the number of patients with mitral regurgitation soars. In patients with heart failure the mitral regurgitation significantly decreases the quality of life and worsens the survival prognosis. Surgical correction is the treatment of choice in patients with mitral regurgitation. However, up to 50% of potential candidates are denied surgery for its prohibitive risk. The minimally invasive, percutaneus procedures are potential solution for those subjects. Currently the „edge to edge” technique with use of the MitraClip system is most commonly performed. This procedure is less efficient in MR reduction than open heart surgery. However, the number of periprocedural complications is smaller. It has been shown the MR correction with the MitraClip device improves the duration and quality of life. There are several ongoing preclinical studies on the percutaneusly implanted mitral valve prosthesis. First in men procedures have been performed. However the mitral valve anatomy is much more complex as compared to aortic. Therefore the breakthrough comparable to TAVI procedure will not occur in the very close future.

Effects of charge composition on microstructure, mechanical and fatigue properties of nodular cast irons have been studied. For experiments, five melts of nodular cast iron were used – three types of unalloyed nodular cast irons (with different ratio of steel and pig iron in a charge and different additives for regulation of the chemical composition) and two types of alloyed nodular cast irons (SiMo- and SiCu- nodular cast iron). The microstructure of the specimens was evaluated according to a norm and by automatic image analysis. The mechanical properties were investigated by the tensile test, impact bending test and Brinell hardness test. The fatigue tests were carried out at sinusoidal cyclic push-pull loading at ambient temperature. The best mechanical properties were reached in the nodular cast iron alloyed by Si and Cu, what is related to its microstructure.

Despite the consensus on the role of lung and pleura ultrasound in human medicine, veteri- nary medicine questions credibility of the pulmonary evaluation in ultrasound examination, based on the analysis of artifacts in animals with clinical signs of respiratory failure and possibility of pulmonary edema diagnosis with recognition of the degree of its severity. The study was conduct- ed on 47 animals (29 dogs and 18 cats) of different breeds, age and sex. In all of animals prior to the transthoracic lung and pleura ultrasound examination (TLPUS), all animals were subjected to a clinical examination and hematological blood test as well as chest radiography examination in three projections. Ultrasound imaging of the chest in each animal was performed at designated four defined segments. TLPUS in dogs and cats based on an analysis of artifacts allows recogni- tion of pulmonary edema, to the degree comparable to chest X-ray examination. The number of depicted B-lines artifacts is proportional to the degree of pulmonary edema. These results allow to reduce the number of radiographs and allow the shortening of the diagnostic process for pa- tients in life-threatening condition.

Technical system for condition monitoring and failure diagnostics of gear driver with roller bearings was tested in situ. The experimental measurement data of rotors shaft vibration displacements were introduced into physical model of gear teeth meshing dynamics. The modelling and simulation of teeth failures in gear driver with roller bearings was performed by finite element method. The experimental and simulation results were used in identification and elimination of sources of gear teeth damages and bearings failures.

Marine structures are one of the most important industrial and military equipment in each country that should be protected against external forces. The main aim of this paper is a detailed investigation of the underwater explosion (UNDEX) and its effects on marine structures. For this purpose, the UNDEX structure was studied qualitatively and quantitatively using numerical methods. Then, the effects of blast waves on a marine structure reinforced by perpendicular blades were investigated. Finite element and finite volume schemes were used for discretization of the governing equations in the solid and fluid media, respectively. Also, for fluid-structure interaction (FSI), results of fluid and solid media were mapped to each other using the two-way FSI coupling methods. A comparison of numerical results with the empirical formula revealed that the trend of pressure-time curves was reasonable, approving the validity of the numerical method. Moreover, the numerical results indicated that detonation of 1 kg trinitrotoluene (TNT) creates a pressure wave with maximum amplitude of 24 MPa at a distance of 2 m. Also, it was found that the reinforcement blades can be used to improve the resistance of structures against explosive charges, which also results in the reduction of structures deformation.

To reliably calibrate suitable partial safety factors, useful for the specification of global condition describing structural safety level in considered design case, usually the evaluation of adequate failure probability is necessary. In accidental fire situation, not only probability of the collapse of load-bearing structure, but also another probability related to the people staying in a building at the moment of fire occurence should be assessed. Those values are different one from another in qualitative sense but they are coupled because they are determined by similar factors. The first one is the conditional probability with the condition that fire has already occured, whereas the second is the probability of failure in case of a potential fire, which can take place in the examined building compartment, but its ignition has not yet appeared. An engineering approach to estimate such both probabilities is presented and widely discussed in the article.

The effects of the miniature channel-shaped scratches not detectable by the present inline electromagnetic defect detection system employed for wires’ surface defect detection on the fracture behaviour of the wires for civil engineering applications were investigated numerically. Finite element analysis revealed that both miniature channel-shaped across-the-thickness and across-the-width scratches change the fracture behaviour of the wires in terms of the fracture initiation locations and fracture process sequence. However, miniature across-the-thickness scratches does not affect the fracture shape of the wire while miniature across-the-width scratches changed the wires’ cup and cone fracture to a fracture shape with a predominantly flat fracture. These results provide an understanding of the fracture behaviour of wires with miniature scratches and serve as an alternative or a complimentary tools to experimental or fractographic failure analysis of wires with miniatures scratches which are difficult to carry out in the laboratory due to the sizes of the scratches.

Shear cracking behaviour of fibrous self-compacting concrete of normal and high strength grade (M30 and M70) is presented here. Two stirrup diameters (6mm Φ and 8 mm Φ) with a constant steel fiber content of 38 kg/m³ (0.5% by volume of concrete) were selected for the present study. The size of the beam was fixed at 100x200x1200mm. The clear span of the beam 1100 mm, was maintained throughout the study. A total of 16 shear-deficient beams were tested under three point loading. Two stirrup spacing (180 mm and 360 mm) are used for the shear span-to-depth ratio (a/d = 2). Investigation indicates that initial cracking load and ultimate load increased as the area of shear reinforcement increased by increasing the diameter of stirrup. It was also noted that the failure mode was modified from brittle shear failure to flexural-shear failure in the presence of fibers. The mechanical behaviour of SFRSCC was improved due to the combined effect of stirrups and steel fibers. The stiffness, toughness, and deflection of the beams increased when compared to SCC beams without fibers. The experimental results were compared with existing models available in literature, and the correlation is satisfactory.

Polish energy security is currently one of the key elements affecting the national security system. Maintaining operational efficiency and the permanent modernization of both, power plants, as well as transformer stations and transmission networks is a starting point of ensuring energy security in our country. This is a significant challenge, taking into account the age of the energy critical infrastructure elements in Poland, as well as the permanent increase of the demand for electricity. This implies a systematic growth of the importance of the issue the country’s energy security. The numerous events and anomalies that accompany our everyday life, such as the storms that passed over Poland on the night of August 11–12, 2017, indicate the considerable sensitivity of the critical energy infrastructure on the impact of various negative factors. The security of Polish critical infrastructure connected with the distribution of electricity is particularly at risk. Therefore, it is desirable not only for current repairs and the modernization of the power system elements, but also for the work related to adapting the infrastructure to current and even forecasted needs, challenges and threats. In the face of the presented research results, the reconstruction of the Polish power system, as well as the implementation of innovative solutions in the production, transmission and distribution of energy seems to be unavoidable. Therefore interdisciplinary research and analyses are recommended, allowing the level security of the critical infrastructure to be increased through the best possible diagnosis of factors that may even slightly threaten this security.

The article provides an overview of the supranational bank resolution regime established under the Single Resolution Mechanism framework. Both the substantive rules governing the resolution process and its procedural requirements are explained. The main focus of the article is the decision-making practice of the Single Resolution Board (SRB), an EU agency responsible for the execution of the resolution framework, which has already intervened in a number of cases in which banks were considered “failing or likely to fail” by the European Central Bank. The article analyses the existing decisions on resolution action in order to establish how the substantive rules on resolution are interpreted by the SRB in its decision-making practice.

The aim of the study was to develop an assessment methodology for the temperature of the surface of the friction pair during the braking for mine hoists. During the braking process, the work of friction is transformed into heat at the level of friction surfaces, and in case high temperatures are reached, the friction coefficient is influenced negatively, thus the risk of braking failure exists. In the first part of the study we measured the temperature of the friction surfaces for a particular case of hoist in real braking conditions. In the second part of the study is presented a theoretical model for the calculation of the temperatures resulted in the braking process for the hoist equipped with shoe brakes. The theoretical model for calculation was simulated numerically for a particular case in real braking conditions. Based on the conclusions resulted after the study, a series of hypotheses and recommendations for adjusting the control of the process parameters have been given out, in order to avoid the excessive heating of the brakes of the hoists and, respectively, their improved safety, maintenance and availability.

This article presents a case study of a large wedge failure. It took place during excavation of the last bench of storage cavern with an approximate dimension of 80 m long having a depth of 8 m. The adopted intervention followed a structured approach, which included immediate rock support, geotechnical and geological investigations in the failure zone and design modifications. Back analyses of the failure zone were also carried out to assess design parameters with observed geological conditions. Re assessment in the failure zone was carried out using modified design parameters, which included shorter benches, rock support installation schemes such as longer rock bolts, reinforced ribs of shotcrete and reduced construction advances. Geotechnical monitoring in and around failure zone were carried out for recording any alarming movements in the rock mass. Initially, geotechnical monitoring was carried out in the recently excavated zone of the cavern on a daily basis. Based on continuous monitoring data for at least one week, the frequency of subsequent monitoring can be decided. In most cases the deformation of rock mass was considerably less than the alarming values which were calculated based on detailed design for different rock classes. The paper discusses the failure, investigation, cause, assessment and remedial measures to complete the construction of cavern.