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

Periwinkle shells and cassava effluent are wastes generated in very large quantities and majorly under-utilized. Due to existence of inefficient waste management systems in developing countries, their disposal is by indiscriminate dumping, a practice that adversely affects the environment and human health. Hence, there is an urgent need to examine their potentials for possible engineering applications in order to further proffer a safe way of managing them. In this work, Periwinkle shell nanopowder and cassava starch were prepared from the wastes and then used to fabricate disc-shaped samples. The samples were developed with various lengths/thicknesses and in triplicates, after which their electrical and dielectric properties were evaluated. For lengths/thicknesses of 2.6 mm to 6.5 mm, the mean electrical resistance and electrical resistivity obtained were (9.89 to 23.00) × 106 Ω and (8.231 × 105) Ωm respectively. Over the temperature range of 20°C to 50°C, the respective results for thermal sensitivity, activation energy, and temperature coefficient of resistance assessment were (6982 ± 158) K, 0.60 eV, and −8.12 %/K. More so, it was observed that quality factor increased with sample’s thickness and frequency of applied signal. With increase in frequency from 0.10 kHz to 100.00 kHz, the dielectric constant of the studied sample decayed exponentially from (20.54 ± 0.04) to (1.67 ± 0.01). Aside meeting the market requirements for NTC thermistors, it was found that the sample could serve as a suitable alternative to conventional dielectrics like mica, paper, plastic film, tantalum oxide, and aluminium oxide for production of capacitors.
</abstract>

Electrical and Dielectric Properties of Discs Fabricated Using Periwinkle Shell Nanopowder and Dry Cassava Starch

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

The present research aimed to electrodeposit and characterize Ni-W alloys for different technological parameters, being an example of “induced co-deposition”, in which a certain metal (for example: Mo, W) can be co-deposited as an alloy, but it cannot be measured in its pure state. The investigated characteristics were the efficiency current, the average thickness, and the structural properties of the obtained deposits. The current efficiency decreases with an increased applied current density, and the tungsten content remains constant at around 11% for different current densities (10 mA·cm−2 and 16 mA·cm−2, respectively). An increase in the temperature of the electrolyte leads to the inclusion of more tungsten. The deposit tungsten content and the current efficiency are directly related to pH. The deposit hardness directly relates to the alloy composition, deposit morphology, and coating thickness. The higher hardness, approximatively 100 HV were measured and the optimal brightness were observed for the alloys obtained at increased current density (i = 16 mA·cm−2, T = 50°C, pH = 8), or to a basic pH (i = 10 mA·cm−2, T = 50°C, pH = 9.23). The scanning electron microscopy (SEM) technique was used to analyze the surface morphology, and energy dispersive spectroscopy (EDS) analysis was carried out to determine the composition of the alloys. The metallic surface brightness (%) was evaluated using the miniature spectrometer, based on the reflection property of the electrodeposited metallic layer, scanning the all-wavelength range between 200-1100 nm.
</abstract>

“Stefan cel Mare” University of Suceava

“Gheorghe Asachi” Technical University of Iaşi

Faculty of Physics “Alexandru Ioan Cuza” University of Iaşi

Research on Obtaining and Characterizing Ni - W Electroplating Alloys for Micro-Electro Mechanics

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

The aim of the paper is to present the actual state of techniques regarding the influence of cryogenic cooling in turning and milling process.
Processing some materials is impossible without cooling the tool or the processed material. Hard-to-cut materials are increasingly used in industry, so new methods of cooling these materials had to be researched. Cryogenic cooling is the most efficient method to cool down the turning, milling or cutting tools. There are a lot of materials that are not affected by the low temperature of the liquid nitrogen (LN2), on the contrary, they behave better and have better proprieties after being cooled with LN2. On the other hand, there are materials that do not behave very well after cooling them with LN2 because their properties are changed, but with the right equipment, the amount of cooling liquid can be controlled, so that the temperature could be maintained at an optimal level.
This paper highlights the advantages of the cryogenic cooling systems compared to the classic cooling systems (cooling and lubricating in the same time) industrially used.
</abstract>

A Review Regarding Cooling Techniques in the Turning, Milling and Cutting Process

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

The importance of air quality monitoring has been strongly demonstrated in numerous scientific studies. This study, carried out in an intense circular intersection, brings additional arguments that the monitoring of the fine particles like PM1 and PM2.5 that influence in more than 80% the concentration of PM10 particles must be measured at several points. Few were the cases [approx. 20%] in which the increase of PM10 concentrations is given by particles with diameters from 2.5 to 10 μm, most likely caused by the re-suspension of dust particles. Grimm Aerosol Technik Germany and SC INOESY SRL conducted a campaign for monitoring the air quality [PM1, PM2.5, PM10] in Iasi, Stone Bridge area, from 8 to 22 February 2018. The monitoring point was located close (150 m) to the APMIS-01 station of the National Environmental Protection Agency.
</abstract>

Department of Exact Sciences, Faculty of Horticulture

“Ion Ionescu de la Brad” Iasi University of Life Sciences

Environmental Engineering and Management Department

“Gheorghe Asachi” Technical University of Iași

“AlexandruIoanCuza” University of Iaşi

Case Study of the Evidence of PM1&amp; PM2.5 Contribution on PM10 from Podul De Piatra– Iasi City

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

In this paper, certain considerations concerning the atomicity of non-additive set functions are given. Several properties and examples are provided.
</abstract>

Certain Considerations on the Atomicity of Set Functions

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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

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

Electrical and Dielectric Properties of Discs Fabricated Using Periwinkle Shell Nanopowder and Dry Cassava Starch

Research on Obtaining and Characterizing Ni - W Electroplating Alloys for Micro-Electro Mechanics

A Review Regarding Cooling Techniques in the Turning, Milling and Cutting Process

Case Study of the Evidence of PM1& PM2.5 Contribution on PM10 from Podul De Piatra– Iasi City

Certain Considerations on the Atomicity of Set Functions

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