In this paper is presented an analysis of gland seals operation and their influence on the performance of low power steam turbine with two cylinders and steam reheating, which can be used in marine applications. Performed analysis presents a comparison of steam turbine main operating parameters when gland seals operation is neglected (as usual in the most of the literature) and when steam mass flow rates leaked through all gland seals are taken into consideration. Steam mass flow rate leakage through all gland seals reduces produced power of the whole turbine and both of its cylinders. Operation of gland seal mounted at the inlet in the first cylinder of any steam turbine (cylinder which operates with the steam of the highest pressure) has the most notable influence on the reduction of the whole turbine produced power. Gland seal mounted at the outlet of the last turbine cylinder (cylinder which operates with the steam of the lowest pressure) did not have any influence on the reduction of steam turbine produced power. In any detail analysis of a steam turbine (especially the complex turbine with multiple cylinders), gland seals operation should be considered due to their notable influence on the turbine performance.

Abstract Microstructure of austenitic stainless steel is primarily monophasic, i.e. austenitic. However, precipitation of the δ-ferrite in the austenite matrix is possible depending on the chemical composition of steel. δ-Ferrite is stable on room temperature but it transforms into σ-phase, carbides and austenite during heat treatment. In this work, the results of analysis of influence of temperature and time on decomposition of δ-ferrite are presented. Magnetic induction method, microstructure and hardness analyses were used for testing the degree of decomposition of the δ-ferrite. Analysis of results showed that increase in temperature and time increases the degree of decomposition of δ-ferrite.

PURPOSE OF THE STUDY Decline in length of stay is of growing interest for patients, doctors and health insurances. The aim of our study was to assess the safety and length of stay after omission of casting, start of early mobilization and implementation of functional discharge criteria after total elbow arthroplasty (TEA). MATERIAL AND METHODS We retrospectively reviewed all patients' records who received a Coonrad-Morrey TEA in the period from January 1st, 2011 to December 31st, 2018. From these records, indications, demographic information and complications were derived. Length of stay was calculated from the hospital administration. Patients were divided in three groups to evaluate the two changes in post-operative care. RESULTS In total 125 patients receiving 126 Coonrad-Morrey TEAs were included with a mean length of stay of 5.5 days (range 2- 23) for the entire group. Omitting a post-operative cast led to decline in length of stay from 6.2 to 5.4 days (p < 0.001). Introduction of functional discharge criteria in August 2017 declined mean length of stay to 3.8 days (p < 0.001). The surgical technique (triceps-on versus triceps-off) was not a confounder (p = 0.20). Range of motion after one year was not significantly different between groups. DISCUSSION The length of stay declined after omission of a cast, and declined further after introducing functional discharge criteria. Since no higher complication rates were observed, the shortening of length of stay appears to be safe. This is in line with other fast-track programs, i.e. for hip and knee arthroplasty. The surgical technique used were not a confounder for the shortened length of stay, which further adds to the safety of the functional discharge criteria. CONCLUSIONS Omitting a cast and splint as regular post-operative treatment reduced the length of stay significantly without leading to more complications. Introduction of functional discharge criteria lowered the length of stay further without more complications. Key words: fast track rehabilitation, cast, total elbow arthroplasty, length of stay, discharge, complications.

Renewable diesel fuels have the potential to reduce net CO2 emissions, and simultaneously decrease particulate matter (PM) emissions. This study characterized engine-out PM emissions and PM-induced reactive oxygen species (ROS) formation potential. Emissions from a modern heavy-duty diesel engine without external aftertreatment devices, and fueled with petroleum diesel, hydrotreated vegetable oil (HVO) or rapeseed methyl ester (RME) biodiesel were studied. Exhaust gas recirculation (EGR) allowed us to probe the effect of air intake O2 concentration, and thereby combustion temperature, on emissions and ROS formation potential. An increasing level of EGR (decreasing O2 concentration) resulted in a general increase of equivalent black carbon (eBC) emissions and decrease of NOx emissions. At a medium level of EGR (13% intake O2), eBC emissions were reduced for HVO and RME by 30 and 54% respectively compared to petroleum diesel. In general, substantially lower emissions of polycyclic aromatic hydrocarbons (PAHs), including nitro and oxy-PAHs, were observed for RME compared to both HVO and diesel. At low-temperature combustion (LTC, O2 < 10%), CO and hydrocarbon gas emissions increased and an increased fraction of refractory organic carbon and PAHs were found in the particle phase. These altered soot properties have implications for the design of aftertreatment systems and diesel PM measurements with optical techniques. The ROS formation potential per mass of particles increased with increasing engine O2 concentration intake. We hypothesize that this is because soot surface properties evolve with the combustion temperature and become more active as the soot matures into refractory BC, and secondly as the soot surface becomes altered by surface oxidation. At 13% intake O2, the ROS-producing ability was high and of similar magnitude per mass for all fuels. When normalizing by energy output, the lowered emissions for the renewable fuels led to a reduced ROS formation potential.

Introduction: The health implications of Caesarean section are a significant factor in evaluating the use of Caesarean section as a method of completing childbirth. The increased rate of Cesarean section augmenting in a statistical way the health implications of the use of Cesarean section as a way of operative technique of childbirth finalization. Aim: To investigate the incidence of health implications on mother and child after Cesarian section in comparison to vaginal delivery. Methods: In our study, which was conducted as a retrospective-prospective and targeted study, the observed research period is from 2007 to 2019. The data sources are: medical histories, birth protocols and neonatal medical histories. Group A: represents the number of surveyed patients with a Cesarean section in a one-year period (2018) in General Hospital „Prim.dr A. Nakaš“. Group B: represents a control group of the same number of patients born by Caesarean section in 2007 in General Hospital „Prim.dr A.Nakaš“ with all parameters and variables detected in the research group. Evaluation of the examinee’s findings includes: anamnestic data, sonographic data, gynecological finding, colposcopic finding. PAPA test, HPV typing and laboratory findings due to the extensiveness of the study. Results: A comparison of the number of Caesarean sections in BiH before and now shows a statistically significant increase from about 6 caesareans per year to almost 21 Cesarean section per year (p<0.05). This increase led to a statistically significant decrease in perinatal mortality from 30 per thousand per year to only 6 per thousand per year (p<0.05). Complications after Cesarean section during both observed periods are dominated by subjective problems, followed by early complications after Cesarean section. According to the types of complications after Caesarean section, hemorrhages were the most numerous during both examined years, with 1 case of other complications and without a statistically significant difference between the observed years. There were no statistically significant differences in the duration of hospitalization, although in 2007 somewhat longer stay in the hospital after Caesarean section was recorded. Conclusion: Our study has shown that one of the most visible trends in modern perinatology is a significant increase in number of Cesarean sections. This is the basis of long-term side effects of Caesarean section, the frequency of which correlates with the increase in this surgical procedure.

SUMMARY Myxopapillary ependymomas (MPE) of the spinal cord are slow-growing benign tumors most frequently found in adults between 30 and 50 years of age. They arise from the ependyma of the filum terminale and are located in the area of the medullary conus and cauda. The recommended treatment option is gross total resection, while patients undergoing subtotal resection usually require radiotherapy. Complete resection without capsular violation can be curative and is often accomplished by simple resection of the filum above and below the tumor mass. Nevertheless, dissemination and distant treatment failure may occur in approximately 30% of the cases. In this paper, we propose an original MPE classification, which is based upon our personal series report concerned with tumor location and its correlation with the extent of resection. We also provide literature review, discussing surgical technique, tumor recurrence rate and dissemination, and adjuvant treatment. In conclusion, our findings suggest that MPE management based on the proposed 5-type tumor classification is favorable when total surgical resection is performed in carefully selected patients. Yet, further studies on a much broader model is obligatory to confirm this.

This paper investigates the relationship of information communication technology (ICT) and virtual reality (VR), and tourism, or specifically its interrelations and links to tourism sustainability. As a consumer technology, VR is still a relatively new concept, although it has been researched and used in the tourism industry for marketing purposes. The aim is to understand the different aspects of VR and ICTs and potentially link them to sustainability and perspectives on mass tourism, as well as to the potential future developments related to the ability of ICT and tourism to meet the tourists’ needs to a greater extent in the future. By use of the systematic mapping methodology, the insights into these concepts and their relations to each other are provided. The study reveals the evolution and links between the investigated concepts, the existing challenges and solutions, and the remaining gaps. The present findings indicate that VR as a trend in the tourism industry still needs significant work and improvement until it is ready to fully immerse itself into the tourism sector and especially involve itself into the issues concerning tourism and the potential of sustainability concept within the industry. Many of the concerns and conflicts still exist, but the potential of its right implementation is enormous.

Neural networks are important method of machine learning that can be used to predict air quality with high accuracy. Using NARX-SP neural network type, several neural network models are developed to predict concentration of air pollutants in Sarajevo for two prediction cases, for 24th and 48th hour ahead, with different combinations of inputs and outputs. The data used in this paper contain hourly values of meteorological parameters (air humidity, pressure and temperature, wind speed and direction) and concentrations of SO2, PM10, NO2, O3 and CO from 2016 to 2018. Optimal models are selected for both prediction cases. It is concluded that the optimal models have very good performances and can be used to predict concentration of pollutants in Sarajevo with great accuracy and contribute to improve quality of life. By adequate application of optimal models, concentration of air pollutants can be predicted for each hour over the next 48 hours.

Quantum computing has the power to break current cryptographic systems, disrupting online banking, shopping, data storage and communications. Quantum computing also has the power to support stronger more resistant technologies. In this paper, we describe a digital cash scheme created by Dmitry Gavinsky, which utilises the capability of quantum computing. We contribute by setting out the methods for implementing this scheme. For both the creation and verification of quantum coins we convert the algebraic steps into computing steps. As part of this, we describe the methods used to convert information stored on classical bits to information stored on quantum bits.

Abstract Assets such as gold, silver, government bonds are widely considered good hedges against adverse movements in the stock market. At times, market participants move between these markets in order to hedge against any immediate risks. The shifts from one market to another likely create a dynamic relationship between the stock market and other assets. We investigate short-run and long-run causality between the industry returns and the prices of the four assets: gold, silver, oil, and 10-year Treasury bonds. Using symmetric and asymmetric Granger causality, we try to identify different industries within the S&P500 that are caused by movement in the prices of these four assets. Although we were able to find short-run and long-run bidirectional causality between the four asset prices and share returns in many industries, our findings are industry-specific. We discover overwhelming and robust evidence of symmetric and asymmetric causality between 10-Year Treasury yield and returns of almost all 18 industries we considered.