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Stabilization of Lord Shulman Porous thermoelastic system from second spectrum viewpoint
IF 0.9
Afrika Matematika Pub Date : 2025-04-18 DOI: 10.1007/s13370-025-01310-z
Hamza Zougheib, Toufic El Arwadi, Hamed Abderrahmane Bouraoui, Abdelhak Djebabla
{"title":"Stabilization of Lord Shulman Porous thermoelastic system from second spectrum viewpoint","authors":"Hamza Zougheib,&nbsp;Toufic El Arwadi,&nbsp;Hamed Abderrahmane Bouraoui,&nbsp;Abdelhak Djebabla","doi":"10.1007/s13370-025-01310-z","DOIUrl":"10.1007/s13370-025-01310-z","url":null,"abstract":"<div><p>The target of this work is to analyze a one-dimensional thermoelastic porous system under the action of Lord–Shulman heat conduction theory. From a second spectrum perspective, the well-posedness is studied using Faedo–Galerkin approximation, then the exponential stability is established without any assumptions on parameters.</p></div>","PeriodicalId":46107,"journal":{"name":"Afrika Matematika","volume":"36 2","pages":""},"PeriodicalIF":0.9,"publicationDate":"2025-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143845617","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Primary, superharmonic and subharmonic resonances control of an oscillatory cantilever beam excited transversely at its free end
IF 0.9
Afrika Matematika Pub Date : 2025-04-18 DOI: 10.1007/s13370-025-01305-w
Eman Desoky, Magdy Kamel, Ali Kandil
{"title":"Primary, superharmonic and subharmonic resonances control of an oscillatory cantilever beam excited transversely at its free end","authors":"Eman Desoky,&nbsp;Magdy Kamel,&nbsp;Ali Kandil","doi":"10.1007/s13370-025-01305-w","DOIUrl":"10.1007/s13370-025-01305-w","url":null,"abstract":"<div><p>The nonlinear vibrations of a cantilever beam model and the dynamic analysis of several resonances (primary and secondary) controlled by the proportional-derivative (PD) control are studied and discussed. The multiple time-scales method is applied to solve the dynamical system of the cantilever beam where the response curves before and after control are obtained. Through these curves, the stability of the beam’s oscillatory behavior is tested under the effect of different physical parameters. The beam suffers from high vibration amplitudes in each resonance case, especially in the superharmonic and subharmonic resonance cases. Besides the nontrivial amplitude of oscillation, a trivial one appears in some secondary resonance cases. Tuning the control gains can lead to acceptable vibration mitigation levels besides approaching the trivial amplitude in some resonance cases. Accordingly, the analytical and numerical results are compared before and after control to validate the control law.</p></div>","PeriodicalId":46107,"journal":{"name":"Afrika Matematika","volume":"36 2","pages":""},"PeriodicalIF":0.9,"publicationDate":"2025-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s13370-025-01305-w.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143845640","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
On an open question concerning the domination problem in the class of almost BS-compact operators
IF 0.9
Afrika Matematika Pub Date : 2025-04-18 DOI: 10.1007/s13370-025-01300-1
Mohamed Hajji
{"title":"On an open question concerning the domination problem in the class of almost BS-compact operators","authors":"Mohamed Hajji","doi":"10.1007/s13370-025-01300-1","DOIUrl":"10.1007/s13370-025-01300-1","url":null,"abstract":"<div><p>The goal of this note is to give a positive answer to the problem 4.11 in [<i>Almost BS-compact operators and domination problem, Mediterr. J. Math.</i> 18, 258 (2021)]. More precisely, we proved that if a positive operator <i>R</i> on a Banach lattice <i>E</i> is dominated by an almost <i>BS</i>-compact operator <span>(T: E rightarrow E)</span>, then <span>(R^2)</span> is almost <i>BS</i>-compact.</p></div>","PeriodicalId":46107,"journal":{"name":"Afrika Matematika","volume":"36 2","pages":""},"PeriodicalIF":0.9,"publicationDate":"2025-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143845641","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Inductive algebras for the motion group of the plane
IF 0.9
Afrika Matematika Pub Date : 2025-04-18 DOI: 10.1007/s13370-025-01308-7
Promod Sharma, M. K. Vemuri
{"title":"Inductive algebras for the motion group of the plane","authors":"Promod Sharma,&nbsp;M. K. Vemuri","doi":"10.1007/s13370-025-01308-7","DOIUrl":"10.1007/s13370-025-01308-7","url":null,"abstract":"<div><p>Each irreducible representation of the motion group of the plane has a unique maximal inductive algebra, and it is self-adjoint.</p></div>","PeriodicalId":46107,"journal":{"name":"Afrika Matematika","volume":"36 2","pages":""},"PeriodicalIF":0.9,"publicationDate":"2025-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143845642","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
A Power-Cardioid candidate for wind direction modelling motivated by two South African case studies
IF 0.9
Afrika Matematika Pub Date : 2025-04-18 DOI: 10.1007/s13370-025-01306-9
Delene van Wyk-de Ridder, Najmeh Nakhaei Rad, Mohammad Arashi, Johan Ferreira, Andriette Bekker
{"title":"A Power-Cardioid candidate for wind direction modelling motivated by two South African case studies","authors":"Delene van Wyk-de Ridder,&nbsp;Najmeh Nakhaei Rad,&nbsp;Mohammad Arashi,&nbsp;Johan Ferreira,&nbsp;Andriette Bekker","doi":"10.1007/s13370-025-01306-9","DOIUrl":"10.1007/s13370-025-01306-9","url":null,"abstract":"<div><p>Wind energy claims a positive image globally; therefore, accurate modelling of wind direction at generation sites accurately can enhance the potential of this green energy source. The uncertain nature of wind direction can be modelled through probability distributions; in this paper, we propose a flexible yet simple distribution, namely the Power-Cardioid distribution, as an alternative and implementable candidate to model wind direction. After discussing some characteristics, the performance of the Power-Cardioid distribution is evaluated via a simulation study and applied to datasets of two wind farms in South Africa. The numerical results demonstrate that this distribution is a promising and exciting new candidate compared to well-known models within circular statistics.</p></div>","PeriodicalId":46107,"journal":{"name":"Afrika Matematika","volume":"36 2","pages":""},"PeriodicalIF":0.9,"publicationDate":"2025-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s13370-025-01306-9.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143845647","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Universally prestarlike functions associated with generalized telephone numbers
IF 0.9
Afrika Matematika Pub Date : 2025-04-18 DOI: 10.1007/s13370-025-01307-8
G. Murugusundaramoorthy, H. Ö. Güney
{"title":"Universally prestarlike functions associated with generalized telephone numbers","authors":"G. Murugusundaramoorthy,&nbsp;H. Ö. Güney","doi":"10.1007/s13370-025-01307-8","DOIUrl":"10.1007/s13370-025-01307-8","url":null,"abstract":"<div><p>In this paper, we acquaint universally prestarlike generalized functions of order <span>(vartheta )</span> with <span>(vartheta le 1)</span> associated with generalized telephone numbers and we get coefficient bounds for <span>( fin mathscr {R} _{vartheta }^{u}(Psi ))</span> and also for <span>( f^{-1} in mathscr {R} _{vartheta }^{u}(Psi ))</span> which has not been discussed earlier. Further we obtain the Fekete-Szegö functional for the class of universally prestarlike functions and applications to certain probability distribution based on convolution product for such functions.</p></div>","PeriodicalId":46107,"journal":{"name":"Afrika Matematika","volume":"36 2","pages":""},"PeriodicalIF":0.9,"publicationDate":"2025-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143845646","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Analogues of composition operators in the setting of non-commutative symmetric spaces
IF 0.9
Afrika Matematika Pub Date : 2025-04-18 DOI: 10.1007/s13370-025-01315-8
Pierre de Jager
{"title":"Analogues of composition operators in the setting of non-commutative symmetric spaces","authors":"Pierre de Jager","doi":"10.1007/s13370-025-01315-8","DOIUrl":"10.1007/s13370-025-01315-8","url":null,"abstract":"<div><p>Symmetric operator spaces are generalizations of symmetric function spaces such as the classical (commutative) <span>(L^p)</span>-spaces, Orlicz spaces, Lorentz spaces and Banach function spaces. In this setting of (potentially) non-commutative symmetric operator spaces we investigate analogues of composition operators, which are also called quantum composition operators. In particular, we provide sufficient conditions under which a Jordan <span>(*)</span>-homomorphism induces a quantum composition operator between non-commutative symmetric spaces and we characterize those bounded operators between non-commutative symmetric spaces that are quantum composition operators. Furthermore, compactness conditions of quantum composition operators are investigated.</p></div>","PeriodicalId":46107,"journal":{"name":"Afrika Matematika","volume":"36 2","pages":""},"PeriodicalIF":0.9,"publicationDate":"2025-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s13370-025-01315-8.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143845645","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
A generalized metric-type structure with some applications
IF 0.9
Afrika Matematika Pub Date : 2025-04-18 DOI: 10.1007/s13370-025-01302-z
Hallowed O. Olaoluwa, Aminat O. Ige, Johnson O. Olaleru, Mujahid Abbas
{"title":"A generalized metric-type structure with some applications","authors":"Hallowed O. Olaoluwa,&nbsp;Aminat O. Ige,&nbsp;Johnson O. Olaleru,&nbsp;Mujahid Abbas","doi":"10.1007/s13370-025-01302-z","DOIUrl":"10.1007/s13370-025-01302-z","url":null,"abstract":"<div><p>The aim of this paper is to introduce a new class of metric-type spaces called O-metric spaces as a generalization of several metric-type spaces in literature, by constructing a triangle-type inequality that accommodates many binary operations including multiplication and division. Possible metric-type spaces are classified into upward and downward O-metric spaces as O-metrics between identical points are not necessarily minimal. Conditions for passage between upward and downward O-metrics are specified, giving rise to various reverse triangle inequalities. Topologies arising from O-metrics are listed, and properties such as O-convergence, sequential continuity, first countability and T<span>(_2)</span> separation are investigated. It is shown that the topology of an O-metric space can be generated by an upward O-metric on the space hence the focus will be on upward O-metric spaces. With the use of polygon inequalities, a theorem on the existence and uniqueness of fixed points of some contractive-like maps is established in the setting of O-metric spaces, and well known results are obtained as corollaries. Applications to the estimation of distances, polygon inequalities, and optimization of entries in some infinite symmetric matrices are also given.</p></div>","PeriodicalId":46107,"journal":{"name":"Afrika Matematika","volume":"36 2","pages":""},"PeriodicalIF":0.9,"publicationDate":"2025-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143845648","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Improved runs-rules precedence charts for monitoring the process location parameter
IF 0.9
Afrika Matematika Pub Date : 2025-04-18 DOI: 10.1007/s13370-025-01292-y
Schalk William Human, Jean-Claude Malela-Majika, Pierre Kritzinger
{"title":"Improved runs-rules precedence charts for monitoring the process location parameter","authors":"Schalk William Human,&nbsp;Jean-Claude Malela-Majika,&nbsp;Pierre Kritzinger","doi":"10.1007/s13370-025-01292-y","DOIUrl":"10.1007/s13370-025-01292-y","url":null,"abstract":"<div><p>Runs-rules are typically incorporated into control charts to increase their sensitivity to detect small process shifts. However, a drawback of this approach is that the resulting charts are unable to detect large shifts quickly. In this paper, improved runs-rules are introduced to the nonparametric precedence chart to address this limitation by maintaining the sensitivity to small process shifts, while improving the ability to detect large shifts in the process. Performance comparisons between the proposed precedence charts and the precedence charts with standard runs-rules are made in terms of their respective run-length characteristics. The results reveal that the precedence charts with improved runs-rules are superior to the competing charts in detecting large shifts in the process, while maintaining the same sensitivity in the detection of small shifts. A real-life example from the engineering field is given to demonstrate the application and implementation of the new charts.</p></div>","PeriodicalId":46107,"journal":{"name":"Afrika Matematika","volume":"36 2","pages":""},"PeriodicalIF":0.9,"publicationDate":"2025-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s13370-025-01292-y.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143845618","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
On the Trinajstic Descriptor of some graphs
IF 0.9
Afrika Matematika Pub Date : 2025-04-18 DOI: 10.1007/s13370-025-01314-9
Hafiz M. Fraz, Kashif Ali, Farhana Yasmeen, Muhammad Aamer Rashid, Muhammad Farhan Hanif
{"title":"On the Trinajstic Descriptor of some graphs","authors":"Hafiz M. Fraz,&nbsp;Kashif Ali,&nbsp;Farhana Yasmeen,&nbsp;Muhammad Aamer Rashid,&nbsp;Muhammad Farhan Hanif","doi":"10.1007/s13370-025-01314-9","DOIUrl":"10.1007/s13370-025-01314-9","url":null,"abstract":"<div><p>Topological descriptors play a crucial role in various scientific fields, particularly in analyzing the physico-chemical and thermodynamic properties of chemical compounds. Recently, a new topological descriptor, known as the Trinajstić descriptor, has been introduced. For a simple connected graph <span>( G )</span>, the Trinajstić descriptor is defined as </p><div><div><span>$$begin{aligned} NT(G)= sum (n(x)-n(y))^2 forall x,y in V(G) end{aligned}$$</span></div></div><p>Where <span>( n(x) )</span> is the number of vertices whose distance is lesser to <span>( x )</span> than <span>( y )</span> and <span>( n(y) )</span> is the number of vertices whose distance is lesser to <span>( y )</span> than <span>( x )</span>. In this article, we calculate the Trinajstić descriptor for the Kite graph, Fan graph, and Helm graph, expanding its applicability to these graph structures.</p></div>","PeriodicalId":46107,"journal":{"name":"Afrika Matematika","volume":"36 2","pages":""},"PeriodicalIF":0.9,"publicationDate":"2025-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143845619","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
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