rss_2.0BULETINUL INSTITUTULUI POLITEHNIC DIN IAȘI. Secția Matematica. Mecanică Teoretică. Fizică FeedSciendo RSS Feed for BULETINUL INSTITUTULUI POLITEHNIC DIN IAȘI. Secția Matematica. Mecanică Teoretică. Fizică INSTITUTULUI POLITEHNIC DIN IAȘI. Secția Matematica. Mecanică Teoretică. Fizică 's Cover Devices Management System Based on Blockchain Technology<abstract> <title style='display:none'>Abstract</title> <p>The recent use of digital Distributed Ledger Technology (DLT) in the healthcare domain can surpass the existing limitations in the centralized IT systems, such as the lack of security, access control or immutability of the electronic health information. If we discuss about clinical information, this innovative informatics advance gives back the control to the data owner. In decentralized environments, smart contracts allow trustable agreements grounded by irreversible transactions, which permit transparency and traceability. Moreover, smart contracts are the living heart of the decentralized applications that run on DTL. In this work, our attention is focused on medical equipments that helps health staff to diagnose and treat patients keeping much of their clinical data taken in dynamics. Hence, we propose a smart contract-based decentralized application framework for the management of devices, targeting also medical services, meant to facilitate the interaction of the involved entities. Our testing environment is the Ethereum platform, extensively used recently in the healthcare domain, being itself a smart operating system that allows decentralized applications to run on it.</p> </abstract>ARTICLE2022-04-30T00:00:00.000+00:00Walnut (Juglans Regia): A Review of Phytosanitary Properties and Theirs Mathematical Modeling<abstract> <title style='display:none'>Abstract</title> <p>Walnut (Juglans regia L.) is the most widespread walnut in the world. All parts of the plant are important: bark, leaves, dried and green peel of the fruit, septum, core. The benefits of walnuts are due to the presence of phytochemicals such as flavonoids, carotenoids, alkaloids, polyphenols, etc. In addition to the many benefits that walnut has on our health (antibacterial, antioxidant), it also has important phytosanitary and insecticidal properties. Walnuts can be used because of their plant-friendly properties in the form of biopesticides that are safe and can be a viable, inexpensive and cleaner alternative to synthetic products that can be harmful to the environment. This review paper seeks to bring to the fore the available literature on Juglans regia directed on the properties, antifungals and insecticides with action on plants and antibacterials with action on the human body, as well as mathematical models regarding the multiplication of microorganisms.</p> </abstract>ARTICLE2022-04-30T00:00:00.000+00:00General Considerations Related to the Membrane Material Locking Models ‒ A Short Rewiew<abstract> <title style='display:none'>Abstract</title> <p>The problem of clogging membrane pores has become an area of interest for the vast majority of researchers in the field, because according to the literature, membrane materials are very sensitive when it comes to clogging and blocking pores.</p> <p>Therefore, this paper briefly describes the problems that occur during the process of obstruction the pores of the membrane. Models and characteristics of pore blocking mechanisms have also been developed.</p> <p>It is essential to mention that the principal purpose of the paper, which which consisted to review the simulations and classical models that were optimized, used in the analysis processes of clogging of membrane materials, was successfully fulfilled.</p> <p>According to those mentioned, the combined mathematical models of pore blocking (methods combined with three blocking mechanisms using Hagen-Poiseuille’s law or standard 0-order blocking) have proven to be very effective in describing membrane clogging problems.</p> </abstract>ARTICLE2022-04-30T00:00:00.000+00:00A Review of Metallic Materials Corrosion<abstract> <title style='display:none'>Abstract</title> <p>The present manuscript presents a theoretical study for the corrosion process. Corrosion processes are primed and stimulated in 60% of cases by chemical and biological elements. One of the most used biological elements are: bacteria, actinomycetes, microscopic fungi, algae. Corrosion of a solid body results from the transformation of structural bonds in that body. Less than certain influences (water, oxygen, light, etc.) the atom - which is practically neutral - can lose or gain electrons and it is ionized.</p> <p>Brake pads are affected of corrosion process. The conceptions and mathematical symbols serve as the models building blocks. Authors like, Boz M, and other authors demonstrate in their researches that starting with the concept of number, where every mathematical object is a mathematical model.</p> <p>In practice it is not possible to reproduce some experimental, theoretical conditions related to corrosion processes. These processes are therefore, to some extent, different in terms of the applicability of theoretical laws. From a thermodynamic point of view, metals are not stable and due to corrosion, metals tend to return to the stable form of oxides with the help of oxygen and moisture in the air. For this each metal requires certain ionization energy.</p> <p>When establishing the mathematical model, those characteristics of the modeling object are highlighted, which, on the one hand, are informative, and on the other hand, they admit the mathematical form review.</p> </abstract>ARTICLE2022-04-30T00:00:00.000+00:00Mach’s Principle in the Acoustic World<abstract> <title style='display:none'>Abstract</title> <p>The aim of this paper is to investigate the coupled oscillations of multiple bubbles within a cluster. The interaction between a bubble and the other bubbles in a cluster produces an additional mass. For a fixed number of bubbles and uniformly distributed (<italic>N</italic> ---gt------gt--- 1), in case of a certain value of the bubbles number density, we deduce the relations analogous to the Eddington relation (between the cluster radius and the bubble radius) and the Sciama relation (between the cluster radius and the gravitoacoustic radius) according to Mach’s Principle.</p> </abstract>ARTICLE2022-04-30T00:00:00.000+00:00Acoustic Black Hole Generated by a Cluster of Oscillating Bubbles<abstract> <title style='display:none'>Abstract</title> <p>The paper demonstrates that a liquid becomes inhomogeneous in interaction with an oscillating bubbles cluster. Because the refractive index of the liquid around the cluster has a radial variation, a spherical acoustic lens is generated. Under certain restrictive conditions, the acoustic lens behaves like an acoustic black hole.</p> </abstract>ARTICLE2022-04-30T00:00:00.000+00:00A Tumor Growth Model with a „Butterfly” – Type Chaotic Time Attractor. Cancer Evolution Through a Traveling Waves-Type Mechanism<abstract> <title style='display:none'>Abstract</title> <p>In this paper we propose a new tumor growth model, based on the original model developed by Anderson-Chaplain to which we attached Ivancevic’s “butterfly” time attractor. The chaotic behavior provides a more realistic perspective on tumor growth, with uncertainties and uncontrollable long term stochastic effects.</p> </abstract>ARTICLE2022-03-17T00:00:00.000+00:00A “Hidden” Symmetry and Some of Its Implications<abstract> <title style='display:none'>Abstract</title> <p>In Physics, hidden symmetries can either be employed to describe special systems and configurations, or even be used as a basic block of a theory itself. In this paper, a special hidden symmetry of a physical field propagation phenomenon, having strong implications in the interactions theories (a classical Fresnel-type image of light propagation) is analyzed.</p> </abstract>ARTICLE2022-03-17T00:00:00.000+00:00Dispersive Behaviours in Complex Structures<abstract> <title style='display:none'>Abstract</title> <p>In the framework of the Scale Relativity Theory, a fractal Korteweg-de Vries-type equation for describing dispersive behaviours of any complex structure is obtained. In the one-dimensional case, the general solution of this equation show that the dispersive behaviours of any complex structure are given by means of cnoidal oscillation modes. Through these modes degeneration, dispersive behaviours of soliton, soliton-package, harmonic etc. result.</p> </abstract>ARTICLE2022-03-17T00:00:00.000+00:00Employing Atmospheric Sensors and Turbulent Energy Cascade Theory to Quantify Hazardous Airborne Transmissibility<abstract> <title style='display:none'>Abstract</title> <p>Airborne viruses, bacteria, or toxins are dangerous because of the nature of the human transmission pathway through breathing. However, every airborne component must conform to the laws of physics governing atmospheric propagation. Given the fact that most atmospheric flows, at both ground level and throughout the atmosphere, are highly turbulent, the mechanisms of turbulence can be employed to understand the propagation of such components. In this paper, the problem of harmful airborne pathogen transmission is considered in the context of atmospheric turbulence and wall-bounded flow theory. Two approaches are considered: one of them relies on singular measurements of building boundary distances and morphology, and the other relies on constant temperature measurement. The theoretical and practical potential of these approaches is then discussed and explained in a larger urban context.</p> </abstract>ARTICLE2022-03-17T00:00:00.000+00:00On the Study and Possible Applications of Minimally Complex Chaos<abstract> <title style='display:none'>Abstract</title> <p>The nature of chaos is elusive and disputed, however it can be connected to sensitivity to initial conditions caused by nonlinearity of the equations describing chaotic phenomena. A nowhere-near comprehensive list of such equations can still be shown: the Boltzmann equation, Ginzburg-Landau equation, Ishimori equation, Korteweg-de Vries equation, Landau-Lifshitz-Gilbert equation, Navier-Stokes equation, and many more. This disproportionality between input and output creates an analytically-difficult situation, one that is complicated both algebraically and numerically – however, the study of equations that are both simple and chaotic may yield useful connections between algebraic complexity and chaos. Such connections can be used to determine the simplest possible chaotic function, which can be used as a “chaotic operator” for various non-chaotic or chaotic functions, thus reducing the problem of chaos to one based strictly on algebra.</p> </abstract>ARTICLE2022-03-17T00:00:00.000+00:00Atoms of Certain Types of Non-Additive Set Functions<abstract> <title style='display:none'>Abstract</title> <p>In this paper, different considerations on atoms, pseudo-atoms and minimal atoms are given for several types of non-additive set functions. In this sense, their properties, different relationships, examples and counterexamples are given.</p> </abstract>ARTICLE2022-03-03T00:00:00.000+00:00On the Holographic Type Dynamics in Complexity Economics<abstract> <title style='display:none'>Abstract</title> <p>Assimilating any complex economic system with a fractal, in the most general Mandelbrot’s sense, non – differentiable behaviors in its economic dynamics are analyzed. As such, economic dynamics in the form of Schrödinger – type various regimes imply “holographic implementations” of the economic processes through group invariance of SL(2R) – type. Then, by means of previous group invariance as synchronization group between any economic system entities, both the phases and the amplitudes of the entities are affected from a homographic perspective. The usual “synchronization” manifested through the delay of the amplitudes and phases of the entities of the economic system must represent here only a fully particular case. In a special case of synchronization of economic system entities, given by Riccati type gauge, period doubling, damping oscillations, self – modulation and chaotic regimes emerge as natural behaviors in the economic dynamics of the economic processes.</p> </abstract>ARTICLE2022-03-03T00:00:00.000+00:00A Comparative Study of the Properties of Different “Lichid Wood” Presentation Forms<abstract> <title style='display:none'>Abstract</title> <p>The existence of many forms of “liquid wood”, even in the same subgroup, is explained by the fact that the main matrix is made of lignin and lignin can be found in nature in over 60 presentation forms. The lignin molecule is a complex macro – molecule made of three molecules which link together in various shapes. At the same time, structurally speaking, the lignin molecule is dependent on the type of plant species from which it is sourced. It results that the type and the structure of the lignin molecule – and implicitly the “liquid wood” biocomposite matrix – has a major role in the forming and the structuring of every type of “liquid wood”. In the current article, a comparative study of the properties of “liquid wood” pertaining to all three subgroups is presented. The chosen types are: Arboform F45, Arbofill Fichte and Arboblend V2 (which is the subject of the entire study).</p> </abstract>ARTICLE2022-03-03T00:00:00.000+00:00The Relaxation Effects in the Preisach - Néel Model of Patterned Media<abstract> <title style='display:none'>Abstract</title> <p>In this paper, we present the calculation of thermal magnetic viscosity based on numerical simulations of relaxation isotherms curves for a Stoner–Wohlfarth ensemble. The Stoner–Wohlfarth particles is described by two equilibrium states and thermal activation is done by overcoming the energy barrier. For simulations we have used a new Preisach type model for Patterned Media, which takes into account the effects of time and temperature. The magnetization of the system is treated using the Preisach Model for Patterned Media with bimodal interactions field distributions. We have simulated relaxation curves starting from different points on the negative region of the descending branch of the major hysteresis loop and from the obtained data we evaluated the thermal fluctuation field. The results obtained for the linear energy barrier were compared with the non-linear energy barrier.</p> </abstract>ARTICLE2022-03-03T00:00:00.000+00:00The Atom of the Physical “Reality” or the Essentiality of the Vacuum<abstract> <title style='display:none'>Abstract</title> <p>A correlation between the informational Universe and various structures of the Universe (atom, planetary systems, galaxy pairs etc.) are established. The link between these structures can be found in the concept of holography, which can be mathematically explicated through multifractality.</p> </abstract>ARTICLE2022-03-03T00:00:00.000+00:00From Classical Newtonian Phylosophy to Skyrmion – A Short History<abstract> <title style='display:none'>Abstract</title> <p>This paper presents a short history from Philosophiae Naturalis Principia Matematica of Newton to skyrmions of Skyrme. It is shown that the classical mechanics does not exclude skyrmions (as topologically stable field configuration of a certain class of non-linear sigma models- for example nucleon model). In certain conditions the Newtonian Theory becomes fundamental in building of modern physics theories (as quantum mechanics, fields theories, etc.).</p> </abstract>ARTICLE2022-03-03T00:00:00.000+00:00Some Mechanical Properties of Arboblend V2<abstract> <title style='display:none'>Abstract</title> <p>The Arboblend V2 biopolymer composite with a matrix based on lignin behaves like a synthetic thermo-injectable polymer, so its use in various sectors does not involve additional costs for obtaining various objects, landmarks using installations injection, extrusion being used in case of synthetic polymers: polyethylene, polypropylene, etc. Compared to plastics obtained from finite sources (oil, natural gas etc.) this material has several specific properties that make it a viable replacement of plastics: it is obtained from renewable raw materials, it is biodegradable in various conditions and, if reinforced with other substances (<italic>e.g</italic>. Kevlar 3%), becomes fireproof. Through the current paper, we determined the behavior of Arboblend V2 as a force of traction and a force shock. The results will lead to finding the best solutions for using Arboblend V2 and its specific properties that sets it apart from other materials.</p> </abstract>ARTICLE2022-02-18T00:00:00.000+00:00A New Theoretical Model for Evaluating Atrial Fibrillations<abstract> <title style='display:none'>Abstract</title> <p>By using mathematical formulations specific to nonlinear dynamics, we devise an original method for the evaluation of atrial fibrillations. Our results can be used for developing new medical diagnosis procedures and new ways of tracking heart diseases, based on specific patterns.</p> </abstract>ARTICLE2022-02-18T00:00:00.000+00:00The Ether Made Explicit Through Light, A Possible Universal Informational Matrix<abstract> <title style='display:none'>Abstract</title> <p>Supossing that the ether is an infinite elastic medium, the constitutive material law that describes such a behaviour is determined. In a totally particular case, corresponding both to the stress tensor, and also to the strain tensor, it is shown that this constitutive material equation can be identified with an electromagnetic field, and, by extension, the Universe is of a informational type (universal informational matrix).</p> </abstract>ARTICLE2022-02-18T00:00:00.000+00:00en-us-1