Sebastian Kowalczyk - Academia.edu (original) (raw)

Papers by Sebastian Kowalczyk

Journal of KONES, 2009

This work presents the physical model of changes setting in multilayer bearing of combustion engi... more This work presents the physical model of changes setting in multilayer bearing of combustion engines. It is known, that the slide bearing of high-load combustion engines independently from manufacturing technology, must have a material stability with regard on diffusion process of the alloy components. The present state of materials used on slide multilayer bearings of combustion engines has not changed during the last 30-year. Only small changes and modifications of material multilayer bearings, with the use of the same groups of materials, independently from specific manufacturing technology of bearing and their use were observed. The change of bearings materials, growth of operating requirements of combustion engines, ecological limitation and the price of materials may force changes in present constructional and technological conception of multilayer, in range of materials selection and building the bearings. This work presents the physical model of changes setting in multilayer...

Springer Proceedings in Energy, 2018

This article presents the experimental results of a heat pipe heat exchanger for the lower temper... more This article presents the experimental results of a heat pipe heat exchanger for the lower temperature range of 15–50 °C. It is worth noting that the heat pipes, thanks to the wide temperature range and high efficiency, can soon be used in building engineering. Recognizing the processes taking place in their interior and their work is essential especially in the era of striving to reduce heat loss and avoid unnecessary energy dissipation. The goal of this work was to carry out research and analysis of heat pipes and process condition by the need to save primary energy in both civil engineering and industry. The results show the effects of phase changes for the R134A refrigerant as well as the effect of its amount on the heat and power of the heat pipe. One of the main objectives of the study is to analyze the efficiency of heat pipes for different amounts of working fluid at different temperatures in both the evaporator section (heat delivery) and the condenser section (heat transfer). The paper presents the results of research on real heat exchanger made from copper 1769 mm tube, 18 mm diameter and 1 mm wall thickness. The study involved placing a heat pipe in a tube heat exchanger in a tube to deliver and receive heat to and from a heat pipe.

Applied Sciences, 2021

Reliability of equilibrium state evaluation about settlement slopes in the context of natural and... more Reliability of equilibrium state evaluation about settlement slopes in the context of natural and human-made hazards is a complex issue. The geological structure of the vicinity of the upland slope in the urban environment of Warsaw is characterised by a significant spatial diversification of the layers. This is especially due to the glacitectonics in the Mio-Pliocene clays, which are located shallowly under the sandy tills’ formations. With substantial variability in the clay roof surface, point recognition by drilling is often insufficient. The use of electrical resistivity imaging (ERI) in the quasi-3D variant provides accurate images of the real ground conditions, which is crucial in optimal geotechnical design. In forecasting the behaviour of the slope, it is necessary to quantify the impact of spatially differentiated systems of disturbed layers on changes in the safety factor (SF), which corresponds to the observed landslide activity of the Warsaw Slope. This study concerns n...

Progress in Computational Fluid Dynamics, An International Journal, 2019

Engine intake systems should be carefully designed to provide a uniform flow to all cylinders. Th... more Engine intake systems should be carefully designed to provide a uniform flow to all cylinders. The current note presents the initial phase of the redesign process of an intake manifold of a four cylinder aircraft IC engine. By means of computational fluid dynamics analysis, the deficiency of the initial design in splitting the air flow among the runners is discovered, and an improvement of the original design is proposed. It is shown that a significant improvement in the flow distribution can be achieved by an appropriately installed guide vane, whereas the flow split is observed to be very sensitive to the geometry of the guide vane, necessitating a very careful design.

Wybrane zagadnienia hydrogeologiczne oraz różne aspekty związane z eksploatacją wód podziemnych, 2021

Badania geofizyczne dostarczają przestrzennych informacji o zmienności ośrodka gruntowo-skalnego.... more Badania geofizyczne dostarczają przestrzennych informacji o zmienności ośrodka gruntowo-skalnego. Wyniki zastosowania tych metod, także archiwalne, warto wykorzystywać w prowadzonych hydrogeologicznych pracach dokumentacyjnych. Takim przykładem są zrealizowane badania rozpoznawcze w miejscowości Łobodno w północno-zachodniej części Wyżyny Śląsko-Krakowskiej zlokalizowanej w granicach GZWP nr 326 Częstochowa (E). Przeprowadzone tam pionowe sondowania elektrooporowe, korelowane z profilami wierceń umożliwiły m.in.: (i) zwiększenie głębokości rozpoznania z ok. 70 do 100-150 m p.p.t. obejmując czwartorzędowe grunty gliniasto-piaszczyste przykrywające górnojurajski kompleks wapieni zalegających na środkowojurajskich iłach i marglach, (ii) identyfikację głębokości zalegania różnych utworów gruntowo-skalnych wraz z określeniem reliefu ich stropu, (iii) wskazanie zmienności litologiczno-strukturalnej w obrębie tych samych wydzieleń, (iv) lokalizację większych dyslokacji, (v) dokładniejsze opisanie warunków przepływu wód podziemnych.

Polymers, 2020

An efficient synthesis strategy of a well-defined polylactide–dye conjugate in a controlled fashi... more An efficient synthesis strategy of a well-defined polylactide–dye conjugate in a controlled fashion is presented. The introduction of coloring species as end groups of polylactide (PLA) has been performed by using new homoleptic aminophenolate magnesium or zinc coordination compounds. The molecular structure of metal complexes has been determined in solution by NMR spectroscopy, and in the solid state by X-ray analysis. Lastingly colored polymers were obtained with 2-[4-(Nitrophenylazo)-N-ethylphenylamino]ethanol (Disperse Red 1) and 2-[4-(2-Chloro-4-nitrophenylazo)-N-ethylphenylamino]ethanol (Disperse Red 13) at very high lactide conversions, based on MALDI-ToF measurement, and the macromolecules were nearly fully chain end dye-functionalized. Based on 1H NMR, the DPn of conjugates was in the range of 10–300, which was consistent with the reaction setup. Various methods of gel-permeation chromatography (GPC) analysis were applied, and they demonstrated that the number-average molar...

Polimery, 2019

In the presented paper, two basic strategies that can be used in the processes of chemical recycl... more In the presented paper, two basic strategies that can be used in the processes of chemical recycling of polyester material were described. The first of them involves increasing the molar mass of recycled materials in the solid-state polycondensation (SSP) process and/or joining their chains with various types of substances easily reacting with the end groups of polyesters (so-called extending agents). The essence of the second strategy is the degradation of the material under the influence of various protogenic agents (such as water, alcohols, glycols and amines) to obtain low-molecular products or oligomers that can be used as raw materials in the synthesis of many classes of polymers. The methods that are already used in PET [poly(ethylene terephthalate)] recycling and the possibility of their extension to other types of polyesters are both shown.

Physica B: Condensed Matter, 2019

In the present work, spinel ferrite T 0.35 Zn 0.55 Cu 0.1 Fe 2 O 4 (T = Mn, Ni) nanoparticles hav... more In the present work, spinel ferrite T 0.35 Zn 0.55 Cu 0.1 Fe 2 O 4 (T = Mn, Ni) nanoparticles have been synthesized via the sol-gel method. We have used the X-ray diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) to investigate structural properties. Thermal stability of the samples was checked by Thermo-gravimetric and Differential thermal analysis (TG-DTA). The surface morphology and the shape of the particles were demonstrated by Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). The XRD patterns confirm the formation of the single-phase polycrystalline cubic spinel structure with Fd-3m space group. The average crystallite size evaluated from XRD data is found to be 13.7 nm and 15.6 nm which is consistent with the results of particle size estimated from TEM. The DC resistivity evaluated through the two-probe measurement, lowering of resistivity with a rise in temperature providing the traditional semiconducting behavior of spinel ferrites. The dielectric parameters such as dielectric constant (), ac conductivity (), and dielectric loss are investigated as a ' () function of frequency and temperature. The results of dielectric measurement revealed a general dielectric dispersion due to the Maxwell-Wagner type of interfacial polarization and the hopping of charge carriers between Fe 2+ and Fe 3+ ions. The prepared samples exhibit low dielectric loss and high resistivity which make them suitable for high frequency microwave and power transform applications.

MATEC Web of Conferences, 2017

The article describes the research on the intake manifold for ultralight aircraft engine Vaxell 1... more The article describes the research on the intake manifold for ultralight aircraft engine Vaxell 100i. It presents the actual and new redesigned manifold construction and points out the design requirements. The results of previously made numerical simulation of air flow inside the manifold are discussed. Computer analysis confirmed the appropriateness of internal guide vanes usage to improve the uniform air distribution between cylinders. For verification, a flow bench test stand was made for multicylinder intake manifold testing. A prototype manifold was built with the possibility of guide vane adjustment. The best variant had almost 5 times better uniformity of air distribution comparing to variant without the guide vane. Flow bench results confirmed the conclusions from numerical simulations.

Macromolecules, 2017

Three-arm polylactides (PLA) containing 0.2, 7.6, and 13% of D-lactic acid monomeric units were o... more Three-arm polylactides (PLA) containing 0.2, 7.6, and 13% of D-lactic acid monomeric units were obtained and refunctionalized into ATRP macroinitiators via esterification of hydroxyl groups with 2-bromoisobutyryl bromide. These polymeric matrices underwent enzymatic degradation with various rates and revealed negative results on cytotoxicity and genotoxicity tests. Camptothecin (CPT), which is an anticancer active substance, was transformed into acrylic monomers; however, simple CPT acrylate was not able to polymerization whereas methacrylate with a linker was ready for FRP and ATRP. The latter monomer was used for ATRP initiated with various PLA macroinitiators in order to form block copolymer conjugates of CPT with high load of drug. Based on kinetic studies at various temperatures, it was found out that the polymerization stopped at certain monomer conversion because of the ceiling temperature. The content of CPT in these conjugates was estimated by means of 1 H NMR, quadruple detection array GPC, and elemental analysis and was in the range 8.0−16.9 wt %. The products were morphologically heterogeneous, and the shapes and size of the nano-/microstructures were influenced by crystallinity of the PLA segment which was shown in AFM images. Terpolymer block conjugates consisting of addition PEGMA monomeric units were synthesized as well in order to increase hydrophilicity of the polymers and to protect a lactone ring in CPT structure. The studies on CPT release were carried out in vitro and revealed that the rate of CPT discharge was influenced by the structure of PLA and conjugate composition; however, it was near to zero-order kinetics. The analysis using the Korsmeyer−Peppas model suggests that drug release was governed rather according supercase II transport (n > 1) which shows that it is a highly controlled process.

2016 16th International Conference on Ground Penetrating Radar (GPR), 2016

Ground Penetrating Radar (GPR) investigations were conducted in order to characterize the reflect... more Ground Penetrating Radar (GPR) investigations were conducted in order to characterize the reflection patterns and internal architecture of Vistula River point bars. The study area is situated in the south part of Warsaw (Central Poland), in the Nature Reserve Swiderskie Islands, where fluvial deposits were well accessible due to an unusually low water level in the Vistula River. Ground Penetrating Radar is a non-invasive tool that facilitates easy and quick investigations of subsurface sediments. The study was based on 7 GPR profiles taken on the largest and most accessible point bar. All profiles were collected using ProEx Malâ GPR system with 250 MHz shielded antenna. In this paper characteristic Ground Penetrating Radar profiles are presented, to show the internal architecture of fluvial deposits. Interpretation of selected GPR profiles showed the presence of erosional surfaces and cut-in channels within the investigated point bar.

Engineering Geology, 2017

Abstract Near surface geophysical methods, specifically electrical resistivity imaging (ERI) and ... more Abstract Near surface geophysical methods, specifically electrical resistivity imaging (ERI) and ground penetrating radar (GPR), were used to evaluate anthropogenic transformation in the Marki area, near Warsaw, Poland. Anthropogenic transformation in this region is indicated by the gradual filling of excavation voids in varved clays with various kinds of waste (both municipal and industrial). The S8 Marki bypass expressway was designed to pass through such an area. Recreating the bottom relief of the excavated varved clays, and reliably estimating the degree of anthropogenic transformation would be difficult if only traditional, standard geological engineering investigations were applied. Electrical resistivity is a parameter, which reflects the diverse properties of the geological media. When calibrated with drill hole data, the resistivity enabled the accurate determination of the base of the anthropogenic soil. The GPR method, in contrast, was only useful to a limited extent, because of the high attenuation of electromagnetic waves in most of the deposited man-made soils. From the analysis of the completed surveys, a two-dimensional image of the subsurface ground structure, reflecting the anthropogenic impact on the environment, was obtained. This image was the basis for the development of the schematic model of the geological setting after human interference. The methodologies applied allowed us to interpret the spatial distribution of the different soils, including the anthropogenic soils of low bearing capacity and the probable connection between two aquifers. This information will be crucial for the construction of safe and economic foundations for structures such as roads.

Studia Quaternaria, 2016

The paper is aiming to determinate the extent of the north eastern arm of Kozłowicka buried valle... more The paper is aiming to determinate the extent of the north eastern arm of Kozłowicka buried valley on the grounds of own re search by means of electrical resistivity tomography- ERT and avail able archival researches. On the Hydro-geological map of Poland, Żyrardów sheet (Felter and Nowicki, 1998a, b) Kozłowicka buried valley was differentiated as an individual hydro-geological unit. The results of the anal y sis show that the ex tent of the structure, defined by its up per boundary, differs significantly from the one suggested on the sheet of Hydrogeological map of Poland. Since there was no data avail able in the north eastern part of the dis cussed arm of Kozłowicka buried valley, the northern boundary was defined only based on avail able geoelectrical sounding profiles (Czerwiñska, 1988; Topolewska, 2015). In order to confirm suggested solution, geoelectrical re search by means of electrical resistivity tomography (ERT) was con ducted. The measurements were per formed along 3 pr...

Acta Geologica Polonica, 2016

A newly recognized Mnin restraining stepover is identified in the Permo-Mesozoic cover of the wes... more A newly recognized Mnin restraining stepover is identified in the Permo-Mesozoic cover of the western part of the Late Palaeozoic Holy Cross Mountains Fold Belt (Poland), within a fault pattern consisting of dextral strike-slip faults. The formation of a large contractional structure at the Late Cretaceous – Cenozoic transition displays the significant role of strike-slip faulting along the western border of the Teisseyre-Tornquist Zone, in the foreland of the Polish part of the Carpathian Orogen. Theoretical relationships between the maximum fault offsets/ mean step length, as well as between the maximum fault offsets/mean step width allowed the estimation of the values of possible offsets along the Snochowice and Mieczyn faults forming the Mnin stepover. The estimated values suggest displacements of as much as several tens of kilometres. The observed offset along the Tokarnia Fault and theoretical calculations suggest that the strike-slip faults west of the Late Palaeozoic Holy Cr...

Budownictwo I Inzynieria Środowiska, 2013

The article presents and discusses the reasons for variability of consolidation obtained in conso... more The article presents and discusses the reasons for variability of consolidation obtained in consolidometric tests with continuous loading on samples of green clay from “Belchatow” mine. The obtained values of the filtration coefficient in CL tests are closely related to the consolidation coefficient and they have a wide range of variability. Correct assessment of the reasons for variability of consolidation parameters may enable effective determination of low-permeable soil filtration coefficient in the consolidation tests conducted under continuous loading.

Biuletyn - Panstwowego Instytutu Geologicznego

In this paper there deals with the registration problem of the physical properties of organic soi... more In this paper there deals with the registration problem of the physical properties of organic soils by using chosen geophysical methods. Three geophysical methods were applied to the realization of the problem: ground penetrating radar, vertical electrical sounding and seismic refraction. Investigations were executed on two testing grounds (Żuków and Całowanie), in which there was affirmed an occurrence of the organic soils. The use of geophysical methods group allowed for accurate qualification of occurrence conditions of organic soils.

The paper focuses on selected geophysical methods, which may be applied for the evaluation of the... more The paper focuses on selected geophysical methods, which may be applied for the evaluation of the technical conditions of flood banks. The paper presents and discusses results of geophysical tests (refractive seismic, geo-radar, vertical electrical sounding and electrical resistivity tomography) obtained from the Kobylnica research test site, i.e. for parts of flood banks on the Vistula River in the Mazovia Region. For a part of the flood bank, where geophysical anomalies were presented, and where cones of hydraulic leakages were observed, numerical calculations of the filtration processes (suffosion) were performed. The obtained results of the geophysical investigations were compared with geotechnical investigations.