bluuebunny/crossref_metadata_2025_split huggingface dataset:
Modeling research of city bus fuel consumption for different driving cycles
Authors: Grabowski L 
Published: December 2021

Abstract
Simulation studies can be used to determine the fuel consumption and carbon dioxide emissions of city buses. The operating conditions of such vehicles are characterised by a very high variability of vehicle speed due to the large number of stops along the route of the bus. During vehicle testing, driving cycles are used to replicate the real-world conditions and to achieve repeatable test conditions. Such a driving cycle is a profile of speed represented as a function of time or as a function of distance. The speed profile over time can be an advantageous determinant, based on laboratory tests, for estimating fuel consumption and pollutant emissions of city buses. The research subject of this paper was the simulation of bus driving under simulated urban traffic conditions, carried out by means of the VECTO software. VECTO is a tool designed to perform the calculations of fuel consumption and carbon dioxide emissions of vehicles. It enables to model the powertrain of trucks and buses and to carry out simulations on various routes defined by driving cycles. The test object was a mega class bus, equipped with a 225 kW engine. The bus has three axles, including the rear drive axle. The scope of research included four cycles: urban, interurban, urbandelivery and interurban. Each of these was analysed in terms of speed and road gradient. The aim of this work was to perform a simulation study of the effect of the vehicle traffic conditions on the amount of CO2 emitted and fuel consumption. The obtained results were analysed.
Model of a prototype vehicle powered by a hybrid hydrogen system
Authors: Gilewski M , Czarnigowski J , Hunicz J , Dubeński K , Szafran M , Fronc M 
Published: December 2021

Abstract
The paper presents a physical mathematical model of the movement of a prototype vehicle equipped with an electric drive system powered by two sources of hydrogen fuel cell and supercapacitors. The model is based on the analysis of the forces acting on the vehicle during motion, taking into account both resistance to motion and propulsion. The model also considers the flow of electrical energy from two sources: a hydrogen fuel cell and supercapacitors, taking into account energy buffering. The aim of the model was to develop a tool to analyse fuel consumption at different control strategies of energy flow in a vehicle. The paper also presents the results of model identification for the Hydros prototype vehicle developed at Lublin University of Technology for the Shell Eco Marathon competition. Model validation was performed for a selected run during the 2019 London competition. High agreement of the model with the results of the actual vehicle was obtained.
Mathematical analysis of a self-service car wash in the aspect of application of renewable energy sources
Authors: Geca M J 
Published: December 2021

Abstract
The paper presents a model of a self-service car wash. Sub-models of water, electricity and natural gas consumption were developed. Heated water is used to wash vehicles and in winter to heat the floor. Electricity is mainly used to power high pressure pumps. The data to develop submodels were based on a time series of 1 year from a 5-station car wash located in central Poland. Chemical consumption and costs were not analyzed in this paper. Generally, this data is quite difficult to access and not provided by car wash manufacturers or owners. The developed model allowed estimating the possibility of using renewable energy sources in the form of solar collectors and photovoltaic panels to balance the energy demand of a car wash depending on the number of washing stands and car wash load. Application of solar collectors allows saving 334 m3 of natural gas per year and 11.2 MWh of electricity in the case of applying photovoltaic panels. The amount of electricity consumed by the carwash is so large that mounting the panels on the whole available area will not provide the required amount anyway. Installation of photovoltaic installation on the premises of touchless car wash is justified in the case of connecting the installation to the public network, which was treated as a battery. The cost of maintaining such a battery is 20% of each stored kWh. As a result of the applied solutions, the CO2 emission will be reduced.
Multibody analysis of the opposed-piston aircraft engine vibrations
Authors: Pietrykowski K , Biały M 
Published: December 2021

AbstractOne of the characteristic features of piston engines are vibrations caused by the pistons moving in the cylinders. During the engine design process, it is necessary to determine the level of vibration that can occur in the engine. This is especially important for aircraft engines. Due to the minimization of the weight of the aircraft, it is necessary to limit the factors that may cause damage to the structure. One of these factors is engine vibration, which can cause resonance and, consequently, a dangerous stress concentration. Long-term action of variable loads may also lead to the formation of fatigue cracks. The article presents the results of a multibody analysis of an opposed-piston diesel engine. It is a two-stroke three-cylinder aircraft engine. The engine has two crankshafts and six pistons that run opposite each other, but the rotation of the shafts is shifted in phase 14°. Engine vibration will also be caused by crankshafts which, to reduce weight, are not equipped with counterweights. The calculation results are presented in the form of time courses of forces and displacements on the engine supports and FFT analysis of the vibration velocity. The results show that the maximum vibration velocity is 7 mm/s and occurs at a frequency of 140 Hz, which corresponds to twice the rotational speed of the crankshafts. The results obtained from the tests allow for the selection of the flexible elements used in the real prototype engine supports.
Estimation of differences in selected indices of vibroacoustic signals between healthy and osteoarthritic patellofemoral joints as a potential non-invasive diagnostic tool
Authors: Karpiński R , Krakowski P , Jonak J , Machrowska A , Maciejewski M , Nogalski A 
Published: December 2021

Abstract
Osteoarthritis (OA) is currently the most generic form of joint disease. It is a complex process in which degenerative changes occur in the articular cartilage [AC], subchondral bone, and synovial membrane and can lead to permanent joint failure. The primary and most commonly used method of diagnosing degenerative changes is classic radiography. Magnetic resonance imaging (MRI) may be used to assess the extent of damage to joint surfaces, but this method is limited by the availability of specialised equipment and the excessive cost of the examination. Arthroscopy, an invasive procedure, is considered the “gold standard” in joint diagnosis. The occurrence of degenerative changes is closely related to the friction and lubrication processes within the joint. The main causes of osteoarthritis are a change or lack of synovial fluid, deformation of the joint bones, local damage to the articular cartilage, and a change in the mechanical properties of the articular cartilage due to water loss from the damaged superficial layer. An alternative, non-invasive method that allows for a delicate assessment of the condition of moving joints is vibroarthrography (VAG). The analysis of vibroacoustic signals generated by moving joint surfaces has an immense potential in the non-invasive assessment of the degree of damage to articular cartilage, meniscus and ligaments and the general diagnosis of degenerative diseases. The purpose of this study is to analyse and statistically compare the basic characteristics of vibroacoustic signals recorded with a CM-01B contact microphone placed on the patella for motion in the 90°–0°–90° range in a closed kinetic chain (CKC) in a control group (HC) and a group of patients diagnosed with osteoarthritis (OA), qualified for the knee alloplasty.
Analysis of differences in vibroacoustic signals between healthy and osteoarthritic knees using EMD algorithm and statistical analysis
Authors: Karpiński R , Krakowski P , Jonak J , Machrowska A , Maciejewski M , Nogalski A 
Published: December 2021

Abstract
The knee joint is the largest and one of the most vulnerable and most frequently damaged joints in the human body. It is characterized by a complex structure. All articular surfaces are covered with hyaline cartilage. This cartilage has minimal regenerative capacity. Under the influence of cyclical micro-injuries, inflammatory mediators, prolonged excessive pressure or immobility, and thus disturbance of tissue nutrition, the cartilage becomes susceptible to damage and is easily covered with villi, cracks and abrasion. As a result, this translates into changes in the friction and lubrication processes within the joint and may affect the generated vibroacoustic processes. In this study, the signals recorded in a group of 28 volunteers were analysed, 15 of them were healthy people (HC) and 13 were people diagnosed with osteoarthritis (OA) qualified for surgery. The study aims to check the usefulness of the EMD (Empirical Mode Decomposition) algorithm in the filtration procedures of vibroacoustic signals. This algorithm is most often used in the analysis of signals that are most often nonlinear and non-stationary. Selected statistical indicators, such as RMS, VMS, variance and energy, were determined for the signals constituting the sum of the IMFs (Intrinsic Mode Functions) 1-8, having a normal distribution in the assessment of damage to the articular cartilage of the knee joint. Statistical analysis was performed for the values of individual indicators obtained. The vibroacoustic signals were recorded using CM-01B contact microphones placed in the central part of the medial and lateral joint fissure for movement in the range of 90°–0°–90° in closed kinetic chains (CKC) in the control group (HC) and the group of patients diagnosed with osteoarthritis (OA).
Numerical analysis of the effect of embedment depth on the geometry of the cone failure
Authors: Jonak J , Karpiński R , Wójcik A 
Published: December 2021

Abstract
This paper presents the results of a numerical FEM analysis of the effect of embedment depth on the extent of the failure zone (cone failure) under the effect of an undercut anchor. For the establishment of the other affecting quantities, the formation of the value of the cone failure angle of the rock medium depending on the embedment depth was analysed. The problem is interesting as regards aspects of rock mass loosening during pull-out of undercut anchors. As a result of the analysis, a significant effect of embedment depth on propagation and the extent of cone failure has been found. The increasing value of embedment depth significantly decreases the extent of the failure zone measured on a free rock surface. The increasing value of cone failure angle limits the potential interaction of failure zones in multi-anchor systems.
Application of the finite element method to the design of an ankle orthosis
Authors: Stefańczak D , Gajewski J , Rogala M 
Published: December 2021

Abstract
AFO (Ankle-Foot Orthosis), which covers the ankle and foot, protects and supports the ankle joint as well as the structures around it. It contributes to the maintenance of the correct gait cycle. Owing to orthoses, the functional capacity of the body part is significantly improved, and so is the quality of life for the user. Personalized orthoses, which are adapted to the anatomy of the user, are more and more often produced by the additive methods. The use of 3D printing for the manufacturing medical devices is becoming increasingly common due to the low cost of the whole process, short production time and the possibility of the product personalization. One of the stages in manufacturing AFOs with the additive method is to create a three-dimensional model of the orthosis in CAD software. Finite element analysis was performed to assess the mechanical properties of the orthosis. The influence of geometry and the materials used were investigated with FEM analysis software. As a result of structural analysis during the design stage, the assessment of the medical device in terms of its durability and mechanical resistance without putting the user at risk is possible. On the basis of the obtained results, the structure strength was compared.
Mould design optimisation by FEM
Authors: Ayer O , Kaya O 
Published: December 2021

Abstract
Production can be briefly defined as creating something new as a result of effort. There are many different production methods. With the industrial revolutions, the number of these methods has increased, and these methods have developed. Over time, heavy and laborious work that people had to do began to be done by machines. The casting method, which is one of the most common production methods in the world, is to pour the molten metal or its alloy into a mould cavity suitable for the shape of the desired product and remove it from the mould after it solidifies. In this study, firstly, the manufacturing method by casting was mentioned, and the difficulties of mould design in the casting method were explained. Secondly, the benefits of computer-aided simulation programs for casting are explained. As an example, a model was designed and different runners were added to this model. These models, which were prepared afterwards, were cast in a virtual environment with the FLOW-3D CAST program, which is a simulation program. Casting results and casting defects after these castings were compared and interpreted. The results show that it is important for the casting quality to keep the runner diameters as small as possible in runner designs. Two or three times more air voids are formed in the sand mould casting method compared to the permanent mould casting. Additionally, it was observed that the casting material had less shrinkage in the sand mould casting method. It is concluded that sand mould casting is disadvantageous in terms of the parameter of time.
Structural and tribological properties of the re-casted dental NiCrMo alloy
Authors: Skic A , Beer-Lech K , Szala M , Kamiński M , Krzysiak Z , Pałka K 
Published: December 2021

Abstract
The crisis related to the COVID 19 pandemic caused an increase in nickel prices on the global markets. From this perspective, it seems promising to search for the possibilities of effective recycling of nickel-based alloys as biomaterials. The topic of the recasting of Ni-Cr dental alloys is currently being broadly described in the literature. Nonetheless, there are still no conclusive results on the impact of recasting on the quality of the cast dentures. Considering the aforementioned, for research, the effect of recasting on the wear resistance and microstructure of NiCrMo dental alloy was investigated. The Heraenium NA alloy was used for testing. Abrasion resistance was tested by the ball on disc method. Microstructure and wear trace were observed using an optical microscope and a scanning electron microscope. The tests showed a higher wear resistance of the re-casted material. The average coefficient of friction for the initially cast alloys was 0.664, while for the remelted samples the mean value was 0.441. The tested samples are characterised by an abrasive-adhesive wear mechanism. Piling up of the wear tracks edges was observed – the highest for H100. For the H100 samples, a slightly lower average hardness value (HV10) was observed – 226 compared to 233 (HV10) for the samples made from the re-casted alloy (H0). The presence of a dendritic structure of alloys was demonstrated. Blocky eutectic precipitations are visible against the matrix. The observed growth of interdendritic precipitations constitute a natural barrier for the counterpart material and increases its tribological properties. Obtained results suggest that alloy recasting does not constitute a limitation to its use.
Experimental and computational evaluation of a gas-solid suspension density distribution under circulating fluidized bed conditions
Authors: Mirek P 
Published: December 2021

Abstract
The paper presents the results of operational measurements of the suspension density distribution in the 966 MWth supercritical Circulating Fluidized Bed boiler. The tests were carried out for four different unit thermal loads, i.e. 40, 60, 80, and 100% MCR. The conducted operational measurements showed that the suspension density distribution of the particulate material in the combustion chamber of the CFB boiler has the form of an exponential curve with maximum values occurring in the bottom part of the furnace. On the basis of the operational data, an attempt was made to reflect the suspension density distribution in the combustion chamber of the boiler using the ANSYS CFD software. The calculations were carried out using the Eulerian multiphase model in an unsteady state condition. As revealed by the simulations, the Eulerian multiphase model allows for a quantitative representation of the suspension density distribution of the granular material only for the maximum boiler load. For other thermal loads, quantitative representation of experimental distributions of suspension density using the Eulerian method is possible except for the dense region.
Quantitative study of activated sludge population structure
Authors: Babko R , Pliashechnyk V , Kuzmina T , Zaburko J , Danko Y , Łagód G 
Published: December 2021

Abstract
A quantitative study of the population structure of activated sludge is an important component of biological wastewater treatment control. However, in the studying of live samples of the activated sludge, some complications arise, in particular, associated with the relatively short time of the subsample suitability. A subsample is the part of the sample that is placed on a glass slide and in which organisms are counted. The issue of optimization of counts of organisms with large amplitude of population density is considered. The results of counting ciliated protozoa in activated sludge were described. The samples were counted in 45 sub-samples of 25 µl each. An average of 10 counts was required to achieve high reliability in determining population densities with more than or equal to 1 specimen per 25 µl in sub-samples. For small population densities (less one specimen per 25 µl) of free-swimming, crawling, and sessile ciliates, 30 counts are necessary. When the density of colonial protozoan populations is established, the number of counts should be increased to 40, especially when colonies with significant differences in the number of zooids are found.
Test stand for pulsed jet actuator command and characterization
Authors: Stryczniewicz W , Stalewski W 
Published: December 2021

Abstract
The paper presents a test stand for characterization of a new design of a Pulsed Jet Actuator. The aim of the work was to characterize the performance of the PJA in terms of air parameters in the air supply line and velocity at the PJA outlet. To perform a detailed characterization of the system performance, the test bench comprised: a pressure reductor, a mass flow rate controller, a mass flow rate meter, a pressure sensor, a fast pressure sensor, a flow temperature sensor and a Constant Temperature Anemometer. The PJA was commanded by a real time controller with Field Programmed Gate Array architecture. The experimental results show good agreement with the results of Computational Fluid Dynamics simulations performed at the design stage of the PJA. It has been found that the flow parameters at the PJA nozzle outlet match the design goals. The developed bench testing procedures will be used for silent conditions tests of the PJA system integrated into a leading edge of a wind tunnel model.
Comparative analysis of the hybrid power system topology for a high efficiency prototype vehicle
Authors: Szewc S , Miękina A , Brzyszko T , Czarnigowski J , Górski W , Marszał P 
Published: December 2021

Abstract
The paper presents a comparative analysis of three solutions of the power supply topology of a high-efficiency hybrid vehicle. The analysis was carried out for the Hydros prototype vehicle developed at the Lublin University of Technology for the Shell Eco Marathon competition. This vehicle is driven by an electric motor powered by two energy sources: hydrogen fuel cells and supercapacitors, allowing temporary energy buffering. Three variants of the mutual connection of the two energy sources to a single receiver were analysed, taking into account the voltage converter systems between the individual components of the system. The aim of these analyses was to determine the most energy-efficient solution.
Cavitation erosion damage of self-fluxing NiCrSiB hardfacings deposited by oxy-acetylene powder welding
Authors: Szala M 
Published: December 2021

Abstract
This paper comparatively investigates the cavitation erosion damage of two self-fluxing NiCrSiB hardfacings deposited via the oxy-acetylene powder welding method. Examinations were conducted according to the procedure given by ASTM G32 standard. In order to research cavitation erosion (CE), the vibratory apparatus was employed. The cavitation damaged surfaces were inspected using a scanning electron microscope, optical microscope and surface profilometer. The hardness of the A-NiCrSiB hardfacing equals 908HV while that of C-NiCrSiB amounts to 399HV. The research showed that the CE resistance of C-NiCrSiB is higher than that of A-NiCrSiB. The results demonstrate that in the case of multiphase materials, like the NiCrSiB hardfacings, hardness cannot be the key factor for cavitation erosion damage estimation whereas it is strongly subjected to material microstructure. In order to qualitatively recognise the cavitation erosion damage of the NiCrSiB self-fluxing hardfacings at a given exposure time, the following factors should be respected: physical and mechanical properties, material microstructure and also material loss and eroded surface morphology, both stated at specific testing time. The general idea for the cavitation erosion damage estimation of the NiCrSiB oxy-acetylene welds was presented.
FEM analysis of the opposed-piston aircraft engine block
Authors: Pietrykowski K 
Published: December 2021

AbstractAn important aspect of aircraft engine design is weight minimization. However, excessive weight reduction may reduce mechanical strength of the engine. This is especially important for aero-engines due to consequences of engine failure in flight. The article presents the results of the FEM opposed-piston diesel engine block model tests. The tested engine is a PZL-100 two-stroke three-cylinder aircraft engine with two crankshafts and six pistons. Air is supplied via a mechanical compressor and a turbocharger. Stress in the engine block is induced by the operating process of the engine block. The pressure in the combustion chamber of the analyzed engine is 13 MPa. The pistons in one of the cylinders are then near their TDC, the deflection angle of the connecting rods is small so almost the entire piston force is transferred to the crankshafts and then to the main bearing supports. This results in the occurence of a tensile force for the engine block applied in the bolt holes of the shaft supports. The calculation results are presented as stress and displacement distributions on the surface and selected block sections. The maximum values on the outer surfaces of the block occurred in the area of the compressor attached to the block and reached 39 MPa. Maximum stresses were, however, observed inside the block on the air and exhaust flow separators between the cylinder liners. The stress value on the outlet side reached 44 MPa.