<abstract xmlns="http://www.w3.org/1999/xhtml">

This paper examines a nonlinear investigation of viscoelastic ferromagnetic convection under gravity modulation. A weakly nonlinear instability has been investigated using the perturbation method. Based on the Oldroyd model for ferrofluids, the constitutive equations of the flow model were developed. The coupled system of the Khayat-Lorenz model developed and was numerically solved in the presence of gravity modulation. Heat transfer results are examined for nonlinear theory and neutral stability curves for linear theory. The nonlinear PDE system is transformed into a nonlinear ODE system with similarity transformations up to the second term. The dual effect of the gravity modulation includes stabilizing and destabilizing.
</abstract>

Effect of Gravitation Modulation on Viscoelastic Nonlinear Ferro-Convection

<abstract xmlns="http://www.w3.org/1999/xhtml">

Molecular dynamics (MD) simulations are intensively used to obtain information on the microscopic behavior of a system and to evaluate certain properties which they determine at macroscopic level. But, as well as setting up an experiment in a “wet” laboratory, also setting up a simulation in a virtual enviroment implies many variables that influence the results. Two of the variables are the starting structure of the system and the water model in which it is solvated.
The present work aims to identify an optimal combination of this two variables able to reveal best the transition from an extended to a collapsed conformation for poly(n-isopropylacrylamide) (PNIPAM) thermoresponsive polymer.
</abstract>

“Gheorghe Asachi” Technical University of Iasi

Department of Chemical and Geological Sciences

The Influence of the Starting Structure and Water Model on the Conformation Transition of Poly(N-Isopropylacrylamide) Thermoresponsive Polymer - In Silico Studies

<abstract xmlns="http://www.w3.org/1999/xhtml">

At the end of summer, the episode of atmospheric instability in the Moldavia region, is attributed to the predominantly eastern circulation, which directed air masses from the Asian continent to Romania. This context is the result of the presence of a high-pressure area, located in northern Siberia and extended to north-eastern Europe. Romania was located in the flow of the eastern circulation, behind the warm front.
The emersion of unforeseen factors, as was the case with the transport of dust from the dry regions of Asia, due to background of a circulation from the east, or the specificities of the relief, make it difficult to forecast the phenomena associated with instability. In this sense, atmospheric soundings are among the most used tools in forecasting atmospheric instability. In this sense, we used atmospheric soundings estimated by the GFS and ECMWF numerical forecast models to analyze the atmosphere vertically. Also, the cross-section profiles drawn in the EUMeTrain application showed the differences between the west and the east of Moldavia and described the vertical atmosphere in the analysed interval.
The evolution of the convective episode was described through satellite images. The forecast models anticipated the instability but did not estimate the amounts of cumulative precipitation. The increase in the amount of precipitation was, among other things, attributed to the existence in the atmosphere of Moldavia of dust particles that acted as condensation nuclei that increased the amount of precipitation. High concentrations of dust were also noticed after consistent rain showers, as explained by Cloudnet data processed.
The analysed case was one of the most representative instability episodes for summer of 2022 in Moldavia and played a decisive role in the soil water reserve.
Here’s how air quality and changes in the atmosphere have a major impact on the environment. The notable frequency of detected electrical discharges, was probably also the result of the presence in the atmosphere of suspended dust particles (due to a natural air pollution process), driven towards the Moldavia region.
</abstract>

“Alexandru Ioan Cuza” University of Iaşi

“Gheorghe Asachi” Technical University of Iaşi

Usage of Atmospheric Sounding to Characterize the Meteorological Events on the Night of 23/24 August, 2022

<abstract xmlns="http://www.w3.org/1999/xhtml">

By using SMAs formulations based on Cu-Zn-Al, the electrical resistivity by employment of an Agilent 4294A Precision Impedance Analyzer was analysed. It results that the different percentages of the metals which make up an SMA, do have an important influence upon resistivity. In particular, for one of the analyzed samples, it was observed that the SME was manifested as a form of “electric properties” memory. The experimental data was fitted using both Gaussian and polynomial fitting.
</abstract>

Universitatea “Alexandru Ioan Cuza” din Iasi

Some Electrical Properties of CuAlZn Alloys

<abstract xmlns="http://www.w3.org/1999/xhtml">

Shape memory alloys (SMA in short) exhibit a series of properties which are very different compared to regular metallic materials. One of their main characteristic is the ability to change their geometric shape when subjected to an increase from a low to a high temperature. In certain conditions, this shape change can be reversible, such that the material can “memorize” two geometric shapes: the high temperature shape (the “warm” shape) and the low temperature shape (the “cold” shape). These transformations occur due to an effect known as shape memory effect (SME in short). Moreover, through SME, the material is able to produce mechanical work when shifting from the “cold” shape to the “warm” one [1].
The discovery of these alloys is linked to the highlighting of a specific property which actually pertains to only several of said alloys (being uncommon for a metallic material) and which is known as “rubber-type behavior”.
Many types of SMAs are very expensive, due to their composition (which includes noble metals) and their complex manufacturing technologies.. The most commonly encountered alloys nowadays are Ni-Ti, Cu-Al-Zn and Cu-Al-Ni which are employed in a plethora of practical applications.
</abstract>

“Gheroghe Asachi” Technical University of Iasi

Universitatea “Alexandru Ioan Cuza” University of Iasi

Tensile Behavior of the Experimental CuAlZn Alloys

AHEAD OF PRINT

Volume 70 (2024): Issue 1 (January 2024)

Volume 69 (2023): Issue 1-4 (December 2023)

Volume 68 (2022): Issue 4 (December 2022)

BULETINUL INSTITUTULUI POLITEHNIC DIN IAȘI. Secția Matematica. Mecanică Teoretică. Fizică

Volume 68 (2022): Issue 1 (March 2022)

Volume 67 (2021): Issue 4 (December 2021)

Volume 67 (2021): Issue 3 (September 2021)

Volume 67 (2021): Issue 2 (June 2021)

Volume 67 (2021): Issue 1 (March 2021)

BULLETIN OF THE POLYTECHNIC INSTITUTE FROM IAȘI, Section Mathematics, Theoretical Mechanics, Physics – BIPMF (ISSN-L 1224-7863) is an international journal, with quarterly appearance, for the free publication of research results in theoretical and mathematical physics, mechanics, technical and applied physics, material sciences.  The journal has a broad scope and welcomes contributions spanning experiment, theory, computation and data science. Topical coverage includes physics, mechanics and mathematics, and given their importance in material sciences, interdisciplinary research areas such as polymers and soft matter, materials, nanoscience, surfaces/interfaces are welcomed if they demonstrate insight into physics, seeking to understand mathematical basis of physical phenomena, and solve problems in physics via mathematical approaches. Joined experimental/theoretical studies are particularly appreciated when complementary and based on up-to-date approaches.  BIMMF aims to enhance the interdisciplinary research by connecting the fundamental sciences as physics and mathematics with applicative research concerning the relationships between structure, processing, properties, and performance of materials. It also promotes international exchange of scientific activities.  The journal publishes original research, focused review articles that examine the state of the art, book reviews, technical notes, case studies, and preliminary communications, with no restriction on the length of the papers.  Archiving  Sciendo archives the contents of this journal in Portico - digital long-term preservation service of scholarly books, journals and collections.  Plagiarism Policy  The editorial board is participating in a growing community of Similarity Check System's users in order to ensure that the content published is original and trustworthy. Similarity Check is a medium that allows for comprehensive manuscripts screening, aimed to eliminate plagiarism and provide a high standard and quality peer-review process. sistemantiplagiat.ro/ 

BULETINUL INSTITUTULUI POLITEHNIC DIN IAȘI. Secția Matematica. Mecanică Teoretică. Fizică

BULETINUL INSTITUTULUI POLITEHNIC DIN IAȘI. Secția Matematica. Mecanică Teoretică. Fizică

Effect of Gravitation Modulation on Viscoelastic Nonlinear Ferro-Convection

The Influence of the Starting Structure and Water Model on the Conformation Transition of Poly(N-Isopropylacrylamide) Thermoresponsive Polymer - In Silico Studies

Usage of Atmospheric Sounding to Characterize the Meteorological Events on the Night of 23/24 August, 2022

Some Electrical Properties of CuAlZn Alloys

Tensile Behavior of the Experimental CuAlZn Alloys

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