Autor: Sawicki, B. - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: Single-domain nanoparticle magnetic power losses calibrated with calorimetric measurements
Autorzy:: Miaskowski, A.
Sawicki, B.
Subramanian, M.
Powiązania:: https://bibliotekanauki.pl/articles/202219.pdf
Data publikacji:: 2018
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:: magnetic fluid hyperthermia
calorimetric experiment
magnetic field
numerical modelling
hipertermia płynu magnetycznego
eksperyment kalorymetryczny
pole magnetyczne
modelowanie numeryczne
Opis:: The purpose of this study was to establish a numerical model for calorimetric measurements of magnetic fluids under an alternating magnetic field (AMF). The modified linear response theory (LRT) and Stoner-Wohlfarth theory were applied to investigate heat dissipation from the ferrofluid. The hysteresis area was calculated once the magnetic field value, applied frequency and number weighted distribution of the nanoparticles were known. Magnetic field distribution was calculated for the setup used for performing calorimetric experiments, and field dependent relaxation times were employed to calculate the specific loss power (SLP) in the sample. Subsequently, the results of numerical investigation were compared with the measurements obtained from calorimetric experiments. The Zeeman energy condition was used to delimit the area where LRT is valid. The numerical model calibrated with the calorimetric measurements allowed for the diffusion coefficient and the parameters involved in power dissipation in a ferrofluid to be determined. These parameters were then used to compute total heat dissipation and temperature distribution within the sample. The numerical model matching the calorimetric measurements of heat dissipation from ferrofluids enhanced the reliability of simulations.
Źródło:: Bulletin of the Polish Academy of Sciences. Technical Sciences; 2018, 66, 4; 509-516
0239-7528
Pojawia się w:: Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Influence of Single-Stage and Duplex Shot Peening on Surface Roughness and Residual Stresses in Al Mg5 Mn1 Sc0,8 Zr0,4 Alloy
Autorzy:: Byczkowska, P.
Sawicki, J.
Januszewicz, B.
Stegliński, M.
Powiązania:: https://bibliotekanauki.pl/articles/353741.pdf
Data publikacji:: 2018
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:: shot peening
double shot peening
residual stresses
roughness
Opis:: Conventional shot peening (SP) is cheap surface treatment widely used to enhance fatigue life of mechanical components [3,4]. Basically, it is shooting small particles (shots) on the surface of the sample. However, the process itself is so complex that a lot of companies are not able to optimally employ it due to the amount of parameters that must be controlled all at the same time. The duplex process consists in two stages of shot-peening treatment. The first one consist of shot-peening with spherical cast steel shots or cut wire shots. During the second stage the samples processed in stage one were subject to shot-peening with glass beads. In this work, RSA-501 aluminium alloy was shot peened using shots of different material and diameter and tested using a measurement of residual stresses and surface roughness. Tests and studies conducted so far on RSA-501 aluminium alloy demonstrate that bombardment by a treatment medium in the form of glass beads or shots of various shapes and diameters induces permanent plastic deformation of the surface layer. The roughness achieved after the shot-peening process was determined for each treatment medium. The largest value of Ra parameter was achieved for cut wire shots and this result is consistent with the above-mentioned theoretical knowledge. This medium is the most aggressive one to the surface being treated primarily due to the sharp edges of shots. The duplex process was successful in obtaining higher values of compressive stresses in surface layer than values achievable in conventional single-stage shot peening process.
Źródło:: Archives of Metallurgy and Materials; 2018, 63, 1; 505-511
1733-3490
Pojawia się w:: Archives of Metallurgy and Materials
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: The Effect of Non-Metallic Inclusions Formed as a Result of Deoxidation on the Fatigue Strength of 15CrNi6 and 16MnCr5 Steel
Autorzy:: Lipa, S.
Sawicki, J.
Dybowski, K.
Pietrasik, R.
Januszewicz, B.
Powiązania:: https://bibliotekanauki.pl/articles/353324.pdf
Data publikacji:: 2018
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:: fatigue strength
non-metallic inclusions
thermo-chemical treatment
Opis:: This paper presents the findings of fatigue strength tests of 15CrNi6 steel following low-pressure carburizing and oil quenching, subjected to cycles of one-sided three-point bending. The fatigue fractures were compared with the results of fatigue strength studies of 16MnCr5 steel following low-pressure carburizing and nitrogen quenching. The fatigue tests for 16MnCr5 steel were conducted as part of a high-cycle resonance test, with a pendular bending load. The study also involved an analysis of the effects on non-metallic inclusions in the structure on the mechanism of fatigue destruction. The inclusions were found to initiate fatigue cracks. In both cases, a similar method of a fatigue fissure initiation was observed, independent of the study method or specimen material.
Źródło:: Archives of Metallurgy and Materials; 2018, 63, 3; 1345-1350
1733-3490
Pojawia się w:: Archives of Metallurgy and Materials
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Synergy of the Plastic Treatment HPT and Shot Peening in Aluminium Alloy Al-Mg-Mn-Sc-Zr
Autorzy:: Stegliński, M.
Byczkowska, P.
Sawicki, J.
Kaczmarek, Ł.
Januszewicz, B.
Klich, M.
Powiązania:: https://bibliotekanauki.pl/articles/355364.pdf
Data publikacji:: 2016
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:: high-pressure torsion
shot peening
numerical analysis
residual stresses
fatigue strength
Opis:: An improvement in fatigue strength is one of the main factors enabling the use of high-durability Al-Mg-Mn-Sc-Zr alloys in functional components of mobile robots. As part of this study, a computer simulation was carried out using ANSYS LS-DYNA software that involved the hybridization of high pressure torsion (HPT) and shot peening (SP) forming processes. The numerical analysis was aimed at determining residual stresses and strains that affect the durability and stress characteristics of the analyzed Al alloy. Results of the study indicate that tensile stresses of σ = 300 MPa generated as a result of HPT are transformed into a beneficial stress of σ = 25 MPa resulting from plastic strains caused by SP surface treatment.
Źródło:: Archives of Metallurgy and Materials; 2016, 61, 2B; 1135-1142
1733-3490
Pojawia się w:: Archives of Metallurgy and Materials
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Numerical analysis of thermal stresses in carbon films obtained by the RF PECVD method on the surface of a cannulated screw
Analiza numeryczna naprężeń cieplnych w warstwie węglowej otrzymanej w procesie RF PECVD na powierzchni wkręta kostnego
Autorzy:: Sawicki, J.
Dudek, M.
Kaczmarek, Ł.
Więcek, B.
Świątczak, T.
Olbrycht, R.
Powiązania:: https://bibliotekanauki.pl/articles/350904.pdf
Data publikacji:: 2013
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:: RF PECVD
termografia
warstwy węglowe
naprężenie
modelowanie elementów skończonych
thermography
carbon films
residual stresses
finite element modeling
Opis:: For many years, research on carbon films has been stimulated by the need to simultaneously optimize their biological and mechanical properties and by the challenges related to their deposition on medical implants. The residual mechanical stress occurring inside deposited films is the most important mechanical parameter which leads to the total destruction of these films by cracking and peeling. In the present work, we systematically studied the effect of ion bombardment during the process of radio frequency plasma enhanced chemical vapor deposition (RF PECVD) by monitoring the temperature distribution on a cannulated screw using the infrared technique. The obtained experimental and finite element modeling (FEM) results show that stresses in carbon films deposited on a cannulated screw are quite inhomogeneous and depend on the geometry of the sample and the relative position of the studied contact area between the substrate/film interface and the surface of the film.
Od wielu lat prowadzone są badania mające na celu zredukowanie naprężeń, w węglowych warstwach stosowanych na implanty medyczne, bez pogorszenia własności mechanicznych i biologicznych. Niemniej jednak poznanie mechanizmów wywołujących naprężenia wymaga szczegółowej analizy numerycznej. Wysoka wartość naprężeń mechanicznych występujących w osadzanych warstwach prowadzi poprzez pękanie i odwarstwienie do ich całkowitego zniszczenia, co znacząco organiczna praktyczne wykorzystanie warstw węglowych. W prezentowanej pracy, przeanalizowano wpływ bombardowania jonów podczas procesu plazmochemicznego (RF PECVD) na rozkład temperatury na powierzchni śruby ortopedycznej przy użyciu kamery termowizyjnej. Przeprowadzone eksperymenty i uzyskane rezultaty modelowania (MES) pokazały, ze naprężenia w warstwach węglowych osadzonych na śrubie ortopedycznej sa niejednorodne i zależą od rzeczywistej powierzchni styku pomiędzy podłożem a powłoka jak i geometrii samej próbki.
Źródło:: Archives of Metallurgy and Materials; 2013, 58, 1; 77-81
1733-3490
Pojawia się w:: Archives of Metallurgy and Materials
Dostawca treści:: Biblioteka Nauki

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