Tomas Bata University in Zlín
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Using spatial neighborhoods for parameter adaptation: An improved success history based differential evolution
Get PDFDifferential Evolution (DE) has been widely appraised as a simple yet robust population-based, non-convex optimization algorithm primarily designed for continuous optimization. Two important control parameters of DE are the scale factor F, which controls the amplitude of a perturbation step on the current solutions and the crossover rate Cr, which limits the mixing of components of the parent and the mutant individuals during recombination. We propose a very simple, yet effective, nearest spatial neighborhood-based modification to the adaptation process of the aforesaid parameters in the Success-History based adaptive DE (SHADE) algorithm. SHADE uses a historical archive of the successful F and Cr values to update these parameters and stands out as a very competitive DE variant of current interest. Our proposed modifications can be extended to any SHADE-based DE algorithm like L-SHADE (SHADE with linear population size reduction), jSO (L-SHADE with modified mutation) etc. The enhanced performance of the modified SHADE algorithm is showcased on the IEEE CEC (Congress on Evolutionary Computation) 2013, 2014, 2015, and 2017 benchmark suites by comparing against the DE-based winners of the corresponding competitions. Furthermore, the effectiveness of the proposed neighborhood-based parameter adaptation strategy is demonstrated by using the real-life problems from the IEEE CEC 2011 competition on testing evolutionary algorithms on real-world numerical optimization problems. © 202
Role of injection pressure on fuel atomization and spray penetration on the Thevetia peruviana and Jatropha curcas biodiesel blends with nanoparticle
Get PDFThis study investigates the effect of the injection pressure on the spray characteristics and atomization of the fuel. The novelty of the work lies in examining the injection pressure (IP) at four different scenarios such as 180 MPa, 200 MPa, 220 MPa and 240 MPa. A series of test conducted in the single cylinder engine at three different concentrations of B10 (5% Jatropha curcas and 5% Thevetia peruviana-50 ppm of Fe2O3), B20 (5% Jatropha curcas and 5% Thevetia peruviana-50 ppm of Fe2O3) and B30 (5% Jatropha curcas and 5% Thevetia peruviana-50 ppm of Fe2O3). All the samples were tested for performance and emission characteristics. Based on the procured results, the combination of the dual biodiesel blends improvised the production of higher brake power and lowered specific fuel consumption. Adding two blends together reduced the overall viscosity of the Thevetia peruviana (yellow oleander oil) since the viscosity of the jatropha is lower than the yellow oleander oil. As the concentration of the blends is increased there is a marginal drop in the brake thermal efficiency, however there is an improvement in the brake specific fuel consumptions. In terms of the combustion efficiency, the heat release rates were improvised upon addition of Fe2O3. With regard to the emissions, there is no significant change in the NOx. Nevertheless, there is a drastic reduction in the HC and CO formation has been witnessed. Among various blends, B30 at 240 MPa of IP reported lower emissions than B10 and B20. In order to examine the fuel atomization and spray characteristics, numerical modelling was applied. At 240 MPa, the fuel mixing rates were higher compared to the other injection pressure.RSP-2022/257; King Saud University, KSU; Natural Science Foundation of Jiangsu Province: BK20200775Natural Science Foundation of Jiangsu Province [BK20200775]; "Nan Taihu Lake Elite Plan" Project ([2018] Huzhou, Zhejiang Province) [3]; King Saud University, Riyadh, Saudi Arabia [RSP-2022/257
Unravelling the highly efficient synthesis of individual carbon nanodots from casein micelles and the origin of their competitive constant-blue-red wavelength shift luminescence mechanism for versatile applications
No full textSynthesis of casein-derived carbon nanodots (CND) using a microwave-assisted approach, giving a high product yield (25%), is reported. Casein was used as a sustainable carbon source, and polyvinylpyrrolidone was used as a stabilizer for the nanodots. The size of the prepared amorphous CND corresponds to individual casein coils, which were only partially carbonized. They were obtained due to the disintegration of casein micelles and submicelles within the microwave-assisted solvothermal process. The resulting nanodots had bright photoluminescence, and their electronic structure and optical properties were investigated. A novel competitive model of their luminescence mechanism was introduced to explain a phenomenon beyond the standard models. The synthesized carbon nanodots were used as luminescent ink for anticounterfeit applications. A polymer matrix nanocomposite was prepared by dispersing the nanodots in a flexible and robust poly(styrene-ethylene-butylene-styrene) tri-block copolymer (SEBS) using the solution cast method. For the first time, the effect of CND on the luminescence and mechanical properties of the SEBS/CND self-supporting films was studied. The film was also studied as a phosphor for light-emitting diodes, with a unique experimental setup to avoid self-absorption, which results in low efficiency and eliminates the excess UV transmitted. Because of their high luminescence, photostability, and mechanical properties, these CND could be used as luminescent labels in the packaging and optoelectronics industries.Ministry of Education, Youth and Sports of the Czech Republic Program - DKRVO [RP/CPS/2022/007]; MEYS CR [LM2018110]RP/CPS/2022/007; Ministerstvo Školství, Mládeže a Tělovýchovy, MŠMT; Central European Institute of Technology, CEITEC; Masarykova Univerzita, MU: LM201811
Viscoelastic non-isothermal modeling of film extrusion for membrane production including flow induced crystallization
No full textIn this work, a viscoelastic non-isothermal extrusion film casting model utilizing 1.5-dimensional kinematics according to Silagy et al. ["Study of the stability of the film casting process,"Polym. Eng. Sci. 36, 2614-2625 (1996)] modified Leonov's constitutive equation, crystallinity-dependent relaxation time and elastic modulus, and flow-induced crystallization considering chain stretch, actual temperature, and cooling rate was developed and validated by using an appropriate numerical scheme and relevant experimental data for linear isotactic polypropylene. The model was used in a parametric study to understand the effect of draw ratio, heat transfer coefficient, and flow-induced crystallization on final film crystallinity and neck-in phenomenon using two different approaches to control the stretching intensity: first by adjusting the speed of the chill roll and second by changing the mass flow in the extrusion die. It is believed that the proposed model and results obtained may help to understand the optimal process conditions for the production of polymeric energy storage membranes, which are increasingly important due to their use in rechargeable lithium-ion batteries, disposable lithium batteries, and specialty energy storage. © 2022 Author(s).Grant Agency of the Czech Republic [21-09174S]Grantová Agentura České Republiky, GA ČR: 21-09174
Models of self-regulation mechanisms in peer-rejected students
Get PDFSelf-regulation is a process that may affect the degree of peer rejection but may also be determined by the degree of peer rejection, whereby the degree of acceptance/rejection can influence the processes that lead to the strengthening or weakening of self-regulation. In this study, we concentrate on self-regulatory mechanisms (self-regulated behavior and strategies for emotional regulation) in peer-rejected students compared to non-rejected students. With the aid of structural equation modeling, we identified models of self-regulation mechanisms in three groups of students according to their acceptance/ rejection. These groups differ in the degree of peer rejection, the structure of the regulation of emotional relations, and the degree of self-regulation behavior. The results suggest that peer-rejected students do not form a monolithic group from the perspective of self-regulation mechanisms, as it is possible to identify diverse structures of relations between the self-regulation mechanisms that probably depend, inter alia, on the degree of peer rejection.Czech Science Foundation [GA CR 17-04816S]; Tomas Bata University in Zlin, Faculty of Humanities [RO60211011025/2102]Grantová Agentura České Republiky, GA ČR: GA ČR 17-04816S; Univerzita Tomáše Bati ve Zlíně: RO60211011025/210
Determinants of universities' spin-off creations
Get PDFThe idea of entrepreneurial university seeks to boost the transfer of academic knowledge to firms and foster socio-economic development. The main objective of this paper is to examine the various determinants that influence universities knowledge transfer activities. To fulfil this objective, we draw our dataset from the higher education and business survey (HESA-BCI) conducted across the United Kingdom in the 2017/18 academic year and the partial least square structural equation was used. The Results demonstrated that funding, patents, and rewards all have significant influence on universities spin off creation. The results also showed that patents played a significant mediating role towards universities spin off creation. Findings of this study contribute to validating the important factors that promotes entrepreneurial activities at universities as well as contributing to knowledge transfer activities. The findings have positive implications for researchers, academic entrepreneurs, and university management aiming to exploit and commercialise university knowledge.Internal Grant Agency of the Faculty of Management & Economics of Tomas Bata University in Zlin [IGA/FaME/2021/004, IGA/FaME/2020/003, IGA/FaME/2021/006
Furcellaran surface deposition and its potential in biomedical applications
Get PDFSurface coatings of materials by polysaccharide polymers are an acknowledged strategy to modulate interfacial biocompatibility. Polysaccharides from various algal species represent an attractive source of structurally diverse compounds that have found application in the biomedical field. Furcellaran obtained from the red algae Furcellaria lumbricalis is a potential candidate for biomedical applications due to its gelation properties and mechanical strength. In the present study, immobilization of furcellaran onto polyethylene terephthalate surfaces by a multistep approach was studied. In this approach, N-allylmethylamine was grafted onto a functionalized polyethylene terephthalate (PET) surface via air plasma treatment. Furcellaran, as a bioactive agent, was anchored on such substrates. Surface characteristics were measured by means of contact angle measurements, X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). Subsequently, samples were subjected to selected cell interaction assays, such as antibacterial activity, anticoagulant activity, fibroblasts and stem cell cytocompatibility, to investigate the Furcellaran potential in biomedical applications. Based on these results, furcellaran-coated PET films showed significantly improved embryonic stem cell (ESC) proliferation compared to the initial untreated material.IGA/CPS/2022/001; Ministerstvo Školství, Mládeže a Tělovýchovy, MŠMT: RP/CPS/2022/001, RP/CPS/2022/002; Grantová Agentura České Republiky, GA ČR: 20-28732S; Javna Agencija za Raziskovalno Dejavnost RS, ARRS: L2-3163, P2-0082Internal Grant Agency of Tomas Bata University in Zlin, Czech Republic [IGA/CPS/2022/001]; Ministry of Education, Youth and Sports of the Czech Republic [RP/CPS/2022/001, RP/CPS/2022/002]; Slovenian Research Agency [P2-0082, L2-3163]; Czech Science Foundation [20-28732S
A narrative review on nonalcoholic fatty liver disease and nonalcoholic steatohepatitis versus hepatocellular carcinoma: do you mind?
Get PDFUniversity Hospital Ostrava in the Czech Republic [MZ CR -RVO-FNOs/2019
Study of the differences in the perception of the use of the principles of corporate social responsibility in micro, small and medium-sized enterprises in the V4 countries
Get PDFThe aim of the study was to examine the differences in the perception of the use of selected principles by CSR managers and owners of Micro, Small and Medium-sized Enterprises ( MSMEs) in the V4 countries. The results of our research show that CSR strategies are most used by entrepreneurs and managers of MSMEs in Hungary, Poland and Slovakia. They are the least used in the Czech Republic. The sectoral comparison within the V4 countries highlighted interesting findings. When considering the moral and ethical implications of decision-making, no significant differences were found between the sectors. Differences were found in the perception of the CSR concept and its use in business. The CSR concept was mostly used in tourism and agriculture, to a lesser extent in construction, retail, manufacturing and services. Managers and entrepreneurs understand the link between CSR and gaining reputation and business opportunities and that CSR helps build a competitive advantage. The size of the company affects whether the company can be classified as CSR-oriented. Compared to medium-sized enterprises, micro- enterprises are 45% less likely and small enterprises are 33.5% less likely to be perceived as CSR-oriented. Compared to companies from Slovakia, companies in the Czech Republic are 41% less likely to be perceived as CSR-oriented. Hungarian companies are 70% more likely to be perceived as CSR-oriented compared to companies from Slovakia. Companies run by women are more inclined to apply CSR principles than men.Slovak Research and Development Agency [APVV-21-0188]Agentúra na Podporu Výskumu a Vývoja, APVV: APVV-21-018
Tailor-made dual doping for morphology control of polyaniline chains in cellulose nanofiber-based flexible electrodes: electrical and electrochemical performance
No full textThe present study revealed the effect of combining one strong-inorganic and weak-organic protonic acid dopants on the electrical conductivity and electrochemical properties of flexible free-standing composite electrodes based on polyaniline and nanofibrillated cellulose (NFC) or its carboxylated analog (CNFC), synthesized using a bottom-up approach. Hydrochloric acid (HCl) served as a low molecular weight inorganic dopant while phytic acid (PhA) and poly(2-acrylamido-2-methyl-1-propanesulfonic acid) (PAAMPSA) were chosen as the organic dopants. Both PhA and PAAMPSA acted as secondary dopants in the dually doped composites through the molecular conformation changes of PANI chains. Synergistic increase in the electrical conductivity is observed for dually doped PANI-NFC with the combination of PAAMPSA and HCl in comparison with PhA and HCl. Unlike the PhA, the morphological changes induced by PAAMPSA are more favorable for the enhancement of conductivity. Neither the morphological changes, nor the carboxylation of NFC affected the electrochemical properties of the composites as the specific capacitance values were influenced mainly by the type and the strength of the individual acids. The capacitance values per gram of the dually doped composite with PAAMPSA and HCl increased with the decrease in the NFC or CNFC loading reaching values above 200 F.g(-1) measured at 50 mV.s(-1) of composite for the 80 wt% PANI content. These results highlight the profound impacts of the secondary dopant in PANI on the performance of PANI-based nanocellulose composites.CZ.02.1.01/0.0/0.0/16_025/0007445; Grantová Agentura České Republiky, GA ČR: GAČR No. 21–09830SCzech Science Foundation (GACR) [21-09830S]; European Regional Development Fund-Project (ORGBAT) [CZ.02.1.01/0.0/0.0/16_025/0007445]; Specific University Research [A2_FCHI_2022_007