Witold Pawlowski

Prof. Witold Pawlowski

orcid

Research Focus & Metrics

Academic Career Length

28Years (1999-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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2 September 2022 in Sustainability
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Farqad Talib NajimFarqad Talib Najim
Farqad Talib Najim
SKSami Kaplan
Sami Kaplan
Hayder MohammedHayder Mohammed
Hayder Mohammed
Anmar F. DulaimiAnmar F. Dulaimi
Anmar F. Dulaimi
AAAzher Abed
Azher Abed
WPWitold Pawlowski
Witold Pawlowski
In this research, a numerical analysis is accomplished aiming to investigate the effects of adding a new design fins arrangement to a vertical triplex tube latent heat storage system during the melting mechanism and evaluate the natural convection effect using Ansys Fluent software. In the triplex tube, phase change material (PCM) is included in the middle tube, while the heat transfer fluid (HTF) flows through the interior and exterior pipes. The proposed fins are triangular fins attached to the pipe inside the PCM domain in two different ways: (1) the base of the triangular fins is connected to the pipe, (2) the tip of the triangular fins is attached to the pipe and the base part is directed to the PCM domain. The height of the fins is calculated to have a volume equal to that of the uniform rectangular fins. Three different cases are considered as the final evaluation toward the best case as follows: (1) the uniform fin case (case 3), (2) the reverse triangular fin case with a constant base (case 12), (3) the reverse triangular fin case with a constant height (case 13). The numerical results show that the total melting times for cases 3 and 12 increase by 4.0 and 10.1%, respectively, compared with that for case 13. Since the PCM at the bottom of the heat storage unit melts slower due to the natural convection effect, a flat fin is added to the bottom of the heat storage unit for the best case compared with the uniform fin cases. Furthermore, the heat storage rates for cases 3 and 12 are reduced by 4.5 and 8.5%, respectively, compared with that for case 13, which is selected as the best case due to having the lowest melting time (1978s) and the highest heat storage rate (81.5 W). The general outcome of this research reveals that utilizing the tringle fins enhances the thermal performance and the phase change rate.

15 August 2022 in Symmetry
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MRMuhammad Abaid Ur Rehman
Muhammad Abaid Ur Rehman
JAJamshad Ahmad
Jamshad Ahmad
Ali HassanAli Hassan
Ali Hassan
Jan AwrejcewiczJan Awrejcewicz
Jan Awrejcewicz
WPWitold Pawlowski
Witold Pawlowski
FAFahad M Alharbi
Fahad M Alharbi
This article explores the application of the reduced differential transform method (RDTM) for the computational solutions of two fractional-order cancer tumor models in the Caputo sense: the model based on cancer chemotherapeutic effects which explain the relation between chemotherapeutic drugs, tumor cells, normal cells, and immune cells using a fractional partial differential equations, and the model that describes the different cases of killing rate K of cancer cells (the killing percentage of cancer cells K (I) is dependent on the number of cells, (II) is a function of time only, and (III) is a function of space only). The solutions are presented using Mathematica software as a convergent power series with elegantly computed terms using the suggested technique. The proposed method gives new series form results for various values of gamma. To clarify the complexity of the models, we plot the two- and three-dimensional and contour graphics of the obtained solutions at varied values of fractional-order gamma and the selected system parameters. The solutions are analyzed with fractional and reduced differential transform methods to obtain an idea of invariance regarding the computed solution of the designed mathematical model. The obtained results demonstrate the efficiency and preciseness of the proposed method to achieve a better understanding of chemotherapy effects. It is observed that chemotherapy drugs boost immunity against the specific cancer by decreasing the number of tumor cells, and the killing rate K of cancerous cells depend on the cells concentration.

28 August 2022 in Energies
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Ali HassanAli Hassan
Ali Hassan
AHAzad Hussain
Azad Hussain
MAMubashar Arshad
Mubashar Arshad
Jan AwrejcewiczJan Awrejcewicz
Jan Awrejcewicz
WPWitold Pawlowski
Witold Pawlowski
HKHanen Karamti
Hanen Karamti
This article is an attempt to explore the heat transfer features of the steady three-dimensional rotating flow of magneto-hydrodynamic hybrid nanofluids under the effect of nonlinear radiation over the bi-directional stretching surface. For this purpose, two different nano-particles, namely silver (Ag) and molybdenum di-sulfide (MoS2), were selected. Three different conventional base fluids were utilized to form desired hybrid nanofluids such as water (H2O), engine oil (EO), and ethylene glycol (EG). We obtained steady three-dimensional highly nonlinear partial differential equations. These highly nonlinear partial differential equations cannot be solved analytically, so these equations were handled in MATLAB with the BVP-4C technique with convergence tolerance at 10−6. The graph depicts the effect of the magnetization effect, thermal radiation, and stretching ratio on rotating hybrid nanofluids. Additionally, the impact of thermal radiation on the heat coefficient of three different hybrid nanofluids is being investigated. The augmentation in magnetization decreases the primary velocity, whereas the increment in radiation enhances the primary velocity. The stretching ratio and the presence of higher magnetic forces increase the temperature profile. The concentration profile was enhanced with an increment in the magnetic field, stretching, and rotation ratio. The maximum Nusselt number was achieved for the Ag-MoS2/EO hybrid nanofluid. It was concluded that augmentation in nonlinear radiation enhances the heat transfer coefficient for the examined cases (I) and (II) of the hybrid nanofluids. The Nusselt number doubled for both the examined cases under nonlinear radiation. Moreover, it was discovered that Ag-MoS2/water produced the best heat transfer results under nonlinear radiation. Therefore, the study recommends more frequent exploration of hybrid nanofluids (Ag-MoS2/water) when employing nonlinear radiation to analyze the heat transfer coefficient.

18 August 2022 in Sustainability
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Anmar F. DulaimiAnmar F. Dulaimi
Anmar F. Dulaimi
SAShakir Falih Al-Busaltan
Shakir Falih Al-Busaltan
MKmustafa kadhim
mustafa kadhim
RARuqayah Al-Khafaji
Ruqayah Al-Khafaji
Monower SadiqueMonower Sadique
Monower Sadique
Jasim M. MahdiJasim M. Mahdi
Jasim M. Mahdi
Concerns about the environment, the cost of energy, and safety mean that low-energy cold-mix asphalt materials are very interesting as a potential replacement for present-day hot mix asphalt. The main disadvantage of cold bituminous emulsion mixtures is their poor early life strength, meaning they require a long time to achieve mature strength. This research work aims to study the protentional utilization of waste and by-product materials as a filler in cold emulsion mixtures with mechanical properties comparable to those of traditional hot mix asphalt. Accordingly, cold mix asphalt was prepared to utilize paper sludge ash (PSA) and cement kiln dust (CKD) as a substitution for conventional mineral filler with percentages ranging from 0–6% and 0–4%, respectively. Test results have shown that the incorporation of such waste materials reflected a significant improvement in the mixture’s stiffness and strength evolution. The cementitious reactivity of PSA produces bonding inside the mixtures, while CKD is used as an additive to activate the hydration process of PSA. Therefore, based on the results, it will be easier to build cold mixtures by shortening the amount of time needed to reach full curing conditions.

15 August 2022 in Symmetry
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MAMubashar Arshad
Mubashar Arshad
AHAzad Hussain
Azad Hussain
AEAshraf Elfasakhany
Ashraf Elfasakhany
SGSoumaya Gouadria
Soumaya Gouadria
Jan AwrejcewiczJan Awrejcewicz
Jan Awrejcewicz
FAFahad M Alharbi
Fahad M Alharbi
This article is focused on investigating the convective magneto-hydrodynamic single-phase flow for comparative analysis of two different base fluids above an exponentially stretchable porous surface under the effect of the chemical reaction. The Buongiorno fluid model is incorporated to observe the Thermophoresis and Brownian diffusion in this study. Boussinesq approximation for temperature and concentration are accounted for flow to be naturally convective. In this study, water and ethanol are assumed for comparative analysis. Additionally, to achieve the outcomes of the designed three-dimensional flow boundary value, problem technique is employed to simulate the problem in MATLAB. Increase in the magnetic field, thermophoresis diffusion, temperature exponent, and Prandtl number expand thermal boundary, whereas contraction is observed with an increase in porosity. Shear stress rates in respective directions have decreased with an increase in the stretching ratio of the surface. Moreover, through comparison, reasonably enhanced Nusselt number is observed for water under influence of study parameters while the Nusselt number abruptly decreases for ethanol. High mass coefficients are observed for both examined fluids.

1 June 2015 in Archives of Metallurgy and Materials
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NKNorbert Kępczak
Norbert Kępczak
WPWitold Pawlowski
Witold Pawlowski
Łukasz KaczmarekŁukasz Kaczmarek
Łukasz Kaczmarek
Details var a2a_config = a2a_config || {}; a2a_config.onclick = 1; a2a_config.locale = "pl"; a2a_config.color_main = "D7E5ED"; a2a_config.color_border = "9D9D9D"; a2a_config.color_link_text = "ffffff"; a2a_config.color_link_text_hover = "ffffff"; a2a_config.color_bg = "d9d9d9"; a2a_config.icon_color = "#4e4e4e"; a2a_config.exclude_services = ["dihitt", "delicious", "whatsapp", "dzone", "sms", "stumpedia", "viber", "yahoo_messenger", "google_plus"]; Details PDF BIBTEX RIS Title Cast Iron And Mineral Cast Applied For Machine Tool Bed - Dynamic Behavior Analysis Journal title Archives of Metallurgy and Materials Yearbook 2015 Issue No 2 June Authors Kępczak, N. ; Kaczmarek, Ł. ; Pawłowski, W. Divisions of PAS Nauki Techniczne Publisher Institute of Metallurgy and Materials Science of Polish Academy of Sciences ; Committee of Materials Engineering and Metallurgy of Polish Academy of Sciences Date 2015[2015.01.01 AD - 2015.12.31 AD] Identifier DOI: 10.1515/amm-2015-0254 ; ISSN 1733-3490 Source Archives of Metallurgy and Materials; 2015; No 2 June References Bruni (2007), Hard Turning of an Alloy Steel on a Machine Tool with a Polymer Concrete Bed of Materials Processing Technology, Journal, 493. ; Brecher (2014), Experimental Modal Analysis Using a Tracking Interferometer Manufacturing Technology, CIRP Annals, 345, doi.org/10.1016/j.cirp.2014.03.131 ; Li (2013), Estimation of CNC Machine - tool Dynamic Parameters Based on Random Cutting Excitation Through Operational Modal Analysis of Machine Tools & Manufacture, International Journal, 26. ; Zaghbani (2009), Estimation of Machine - tool Dynamic Parameters During Machining Operation Through Operational Modal Analysis of Machine Tools & Manufacture, International Journal, 947. ; Erbe (2008), Mineral Casting as Material for Machine Base - frames of Precision Machines Twenty - third Annual Meeting of the American Society for Precision Engineering and Twelfth ICPE Portland Oregon, October. ; Zhang (2003), Predicting Dynamic Behaviours of a Whole Machine Tool Structure Based on Computer - aided Engineering of Machine Tools & Manufacture, International Journal, 699. ; Nangolo (2014), A Combined Numerical and Modal Analysis on Vertical Vibration Response of Railway Vehicle Procedia, Engineering, 310. ; Haddad (2012), Optimization of the Polymer Concrete Used for Manufacturing Bases for Precision Tool Machines Part, Composites, 3061, doi.org/10.1016/j.compositesb.2012.05.003 ; Kostyleva (2008), Il inskii Gray cast iron primary structure detachment crack propagation resistance and Heat Treatment, Metal Science, 50, 248.