Romanian Inventors Forum

Iaşi, Romania

Romanian Inventors Forum

Iaşi, Romania
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Mircea O.,Roman Museum of History | Sandu I.,Al. I. Cuza University | Sarghie I.,Technical University Gheorghe Asachi | Sandu A.V.,Romanian Inventors Forum
International Journal of Conservation Science | Year: 2010

This paper presents the experiment results obtained by applying non-invasive methods (OM, SEM-EDX, XRF) on metallic artifacts from the 2nd and the 3rd centuries A. D. (discovered in the Vǎleni-Boteşti and Gabǎra-Moldoveni sites, Neamţ County), with components from different overlapped metals (copper/iron), to determine the surface and the internal microstructure (cross-section), corrosion products distribution and the effect of the two metals in the alteration processes. The results revealed some attributes used in authentication, the determination of the conservation state and allowed us to establish proper procedures for the active conservation and the restoration of those artifacts.


Manea L.R.,Technical University Gheorghe Asachi | Sandu I.,Romanian Inventors Forum | Sandu I.,Al. I. Cuza University
Revista de Chimie | Year: 2015

Electrospinning came into prominence during the last years as a promising procedure to obtain fibers sized under 1μm from a wide variety of polymers. The electrospinning process, technology and equipment are relatively complex, yet efficient, able to produce continuous, exceptionally long fibers, with controlled orientation. Nowadays, the electrospinning technology is the only one able to lead to the formation of continuous filaments, with diameters of some nanometers. The present paper contains a study related to the processability of polyetherimide solution with a concentration of 12%, using as solvents a mixture of dimethylacetamide/tetrahydrofuran 1:1 ratio. Adjusting the flow rate, the distance between needles and collector and the voltage, 100 technological experiments were carried out. The main destination of these nanofibers is filteringsurfaces. All fibers were studied by Scanning Electron Microscope method for analyzing the consistency of fibers disposal, the fibers diameter uniformity, and the presence of defects on fibers.


Manea L.R.,Technical University Gheorghe Asachi | Scarlet R.,Technical University Gheorghe Asachi | Sandu I.,Romanian Inventors Forum | Sandu I.,Al. I. Cuza University
Revista de Chimie | Year: 2015

Any activity dedicated to the evaluation and amplification of qualitative level is based on a deep and systematic analysis of flaws. This represents in fact an analysis of quality by means of non-quality. Utilization of a new polymer with a specific structure as a raw material needs a study on the flaws appeared on the surface of fibrous deposits. The analysis of non-quality is related to the determination and characterization of the appeared flaws and the analysis of the causes which generate them, such as: the raw material through its characteristics, the equipment by its technological and constructive parameters, environmental parameters, as well as lack of correlation between the specified parameters and characteristics. The present paper contains a study related to a series of flaws appeared through electrospinning of a polymeric solution of polyetherimide (PEI) with a concentration of 12%, using as solvent a mixture of dimethylacetamide/tetrahydrofuran (DMACITHF), 1:1 ratio. Fibers obtained through electrospinning were studied by Scanning Electron Microscope method to analyze the appeared flaws in correlation with their technical and technological causes.


Manea L.R.,Technical University Gheorghe Asachi | Nechita E.,Vasile Alecsandri University of Bacu | Sandu I.,Romanian Inventors Forum | Sandu I.,Al. I. Cuza University
Revista de Chimie | Year: 2015

The transversal dimension of electrospun fibers depends on a multitude of technological, constructive and environment factors and not finally, on the characteristics of polymeric solution. This study has examined the effect of the nozzle sizes on the diameter of the fibers of 12% polyetherimide (PEI) solution using as solvent dimethyl acetamide Itetrahydrofuran (DMAC/THF), 1:1 ratio. The polymer solution was processed at two values of nozzle size, and the voltage, feed rate and spinning distance were also varied. Processing with different parameters resulted in the production of fibers with diameters varying between 208 and 738nm. When the diameter of the nozzle size of the needle decreases, the surface tension of the drop increases and diminishes the resulted fibers diameter.


Scarlet R.,Technical University Gheorghe Asachi | Manea L.R.,Technical University Gheorghe Asachi | Sandu I,Al. I. Cuza University | Cramariuc B.,Tampere University of Technology | And 2 more authors.
Revista de Chimie | Year: 2012

This paper discusses the influence of the needle - collector distance (constructive parameter of the electrospinning process) upon the characteristics of the nanofibers from the view point of their diameter and levelness, nanofibers obtained from a mixture of polyetherimide with dimethylacetamide/ tetrahydrofuran (DMAC/THF), 1:1 ratio, through electrostatic spinning. The obtained nano fibers were studied by scanning electron microscope.


Deliu R.,Technical University Gheorghe Asachi | Sandu I.,Al. I. Cuza University | Butnaru R.,Technical University Gheorghe Asachi | Sandip I.G.,Romanian Inventors Forum | And 2 more authors.
Revista de Chimie | Year: 2012

The paper presents the influence of some parameters involved in needleless electrospinning technology on the structure and morphology of polyvinyl alcohol nano fibers. Based on theoretical and practical aspects of the nanonbers obtained by needleless electrospinning technology and of the polyvinyl alcohol characteristics, were determined the areas of polymer concentration and the characteristics of the applied voltage, involving an electrospinning device equipped with a rod spinning electrode with a diameter of 8 mm and a lenght of 170 mm. The applied voltage to the rod spinning electrode was between 0-40 W, domain in which the influence on the elongationlevel of the jet can be felt, with a direct action on the surface morphology of the nanonbers and on the relaxation time of the polymer, respectively. Regarding the concentration of polyvinyl alcohol aqueous solution, it was found that using low concentrations (5% wt), no matter what the value of the voltage is, instead of nano fibers droplets are formed and the electrospraying process appears. Instead, increasing the solution concentration causes a fusion of the droplets in nano fibers. Because droplets modified from spherical to spindle-like form and the distance between droplets increases with increasing viscosity, uniform nanonbers with larger diameters can be obtained. The range of concentrations where uniform nanonbers can be obtained, without beads on the surface, is between 10% wt and 16% wt polyvinyl alcohol in water.


Manea L.R.,Technical University Gheorghe Asachi | Manea L.R.,Al. I. Cuza University | Danu M.C.,University of Bacau | Sandu I.,Romanian Inventors Forum | Sandu I.,Al. I. Cuza University
Revista de Chimie | Year: 2015

Producing nanomaterials is a major priority in the European and international research. Given their large surface and porosity, fibers are successfully used in various medical applications (artiricial organs, biomedical applications, prostheses etc.), cosmetics, filtering mediums, absorbent layers in protection clothes etc. A series of technological, constructive and environmental factors have a synergetic action on the electrospinning process. The present work proposes to study the influence of technological factors for the electrospinning process, on fiber diameter in the case of processing the polyetherimide (PEI) in concentration of 12%, using as solvents dimethylacetamide/ tetrahydrofuran (DMAC/THF), 1:1 ratio. The obtained nanofibers were studied by scanning electron microscope, pursueing also the influence of the applied voltage and flow rate on their diameter fibers.


Manea L.R.,Technical University Gheorghe Asachi | Scarlet R.,Technical University Gheorghe Asachi | Leon A.L.,Technical University Gheorghe Asachi | Sandu I.,Romanian Inventors Forum | Sandu I.,Al. I. Cuza University
Revista de Chimie | Year: 2015

The electrospinning technological process occurs under the influence of a plurality of factors chosen by the specialists for the evaluation of the correlation between the specific result as the effect of the process (nanofibers with special destinations) and its causes. The application of the statistic control in the electrospinning process is a premise for the production of highly uniform nanofibers with pre-established characteristics. The utilization of statistic control permits the evaluation of the state of static and dynamic stability, with significant implications in nanofibers quality. The polyetherimide-based nanofibers were obtained with modular electrospinning equipment, using as solvents dimethylacetamide, tetrahydrofuran and dimethyl sulfoxide. The values of fibers diameters were statistically processed, with the aim to improve the processing quality and to reduce the variability of technological electrospinning parameters.


Mircea O.,Al. I. Cuza University | Sandu I.,Al. I. Cuza University | Vasilache V.,Al. I. Cuza University | Sandu A.V.,Romanian Inventors Forum | Sandu A.V.,Technical University Gheorghe Asachi
Microscopy Research and Technique | Year: 2012

This article presents the atypical formations in the structure of the corrosion crust and in the partially mineralized metallic core, which resulted during the underground stay of a bronze shield, dated between the 1st century B.C. and the 1st century A.D. For our study, we choose a representative fragment from the rim of the shield, which was analyzed by optical microscopy and by electron microscopy coupled with energy-dispersive X-ray spectroscopy, to study its morphology, its composition, and the location of chemical compounds on the surface and inside the bulk formed during the underground stay, by processes of chemical and physical alteration, assisted by contamination with structural elements from the site. Those processes, by monolithization and mineralization formed a series of structures consisting of congruent elements and phases with a complex composition. Those formations, defined as surface effects generated by exogenous factors and endogenous factors inside the bulk, are frequently found in ancient bronze objects (such as the exterior flat mole formations and the Liesegang effect in the stratigraphic structure of the bulk). Some of those structures have atypical characteristics as regards their structure, composition, and formation mechanism, which may be used in archeometry. Moreover, that includes the object in the category of special cases, in terms of artifact evolution during underground stay and of the atypical formations resulted from the action of pedological and environmental factors. © 2012 Wiley Periodicals, Inc.


Tanase S.I.,Al. I. Cuza University | Tanase D.,Al. I. Cuza University | Pascariu P.,Al. I. Cuza University | Vlad L.,Al. I. Cuza University | And 2 more authors.
Materials Science and Engineering B: Solid-State Materials for Advanced Technology | Year: 2010

In this work, we report on experimental investigation of the influence of nitrogen addition on magnetic and transport properties of Co-Ni granular films with different nitrogen content correlated with the surface morphology. The granular thin films were electrodeposited on aluminium substrate, from the following base solution: 30 g/l CoSO4·7H2O, 50 g/l NiSO4·7H2O, 10 g/l NiCl2·6H2O, 50 g/l Na2SO4·10H2O, 30 g/l H3BO3 and 10 g/l NaCl. Sodium laurylsulphate (C12H25NaO4S) and sodium saccharine (NaC7H4O3NS·2H2O) were used as additives. As a source for nitrogen inclusion in the films by cationic catalysis, sodium nitrate (NaNO3) was introduced in the electrolyte. The concentration of NaNO3 in electrolytic bath was varied with the aim to control the films nitrogen content. Co-Ni-N/Al granular films display tunneling magnetoresistance (2-160%) effect which could be explained mainly by the elastic spin-dependent scattering of conduction electrons at the interface between magnetic grains (constituted of Co-Ni solid solution) and nonmagnetic regions (rich in N inter-granular frontiers and aluminium oxidized substrate). © 2010 Elsevier B.V. All rights reserved.

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