Faculty Of Materials Science Research Articles

WORK SAFETY SELF-ASSESSMENT. APPLICATION, WORK LOAD

The occupational safety self-assessment system for small and medium-sized enterprises (SMEs) is a powerful tool, through which SMEs or departments of a large enterprise can decide where and how occupational safety and health activity should be improved through concrete proposals and prioritization. In the paper we deal with the self-assessment of the independent component of the work system, namely the work load, at the Metal Casting Laboratory within the Faculty of Materials Science and Engineering of the "Gheorghe Asachi" Technical University in Iași. The aim is both to achieve the qualitative assessment through the Weaknesses - Strengths table, as well as to achieve the quantitative assessment by obtaining that Score that leads us to a qualification corresponding to the value of the score. These evaluations, qualitative and quantitative, lead us to adopt measures to improve or maintain work security at a level close to the level of safety for which the company or department was designed.

Influence of selected parameters of drag finishing on tool microgeometry

The aim of the experiment described in the paper was to determine how selected parameters of drag finishing such as process time, immersion depth and rotation frequency affect microgeometry of cutting edge. Four flute cemented carbide mills with diameter of 10 mm were used in this experiment. These mills were drag finished on prototype drag finishing machine developed on Faculty of Materials Science and Technology, Slovak University of Technology. Alicona Infinte Focus SL measuring machine was used to measure microgeometry of these mills. The main parameter of microgeometry of cutting edge was the size of the radius of cutting edge. In the article we compared which parameter has the biggest influence on size of cutting edge radius and also there was statistical evaluation carried out. The most significant parameter of drag finishing was determined to be the immersion depth.

DESIGN THINKING FOR SPECIFIC PURPOSES: COMPARATIVE STUDY OF DESIGN THINKING TECHNIQUE TO ENHANCE EDUCATIONAL PROCESS FOR STUDENTS OF ENGLISH AND TEACHERS OF VARIOUS ACADEMIC FIELDS

Design thinking is a dynamic approach and mindset employed to explore innovative and creative solutions to a wide range of challenges. At its core, design thinking places significant emphasis on the individual, their emotions and needs. Professionals who embrace design thinking actively seek out issues that impact people and offer appropriate solutions that will benefit users. Consequently, design thinking is an ongoing and iterative process, continuously researching and enhancing a product or service to the user’s satisfaction. This study aims to compare how English language and culture in specialized communication students and university teachers of various academic disciplines at the University of Ss. Cyril and Methodius in Trnava and the Faculty of Materials Science and Technology at Trnava, Slovak University of Technology in Bratislava, Slovakia, perceive the application of design thinking in the educational process. Two workshops were conducted to explore the application of design thinking in American literature seminars, with a total of 45 students who took part in the survey. The third workshop focused on enhancing intercultural awareness through online seminars and searching for the most appropriate methods of teaching intercultural communication in the online space. The workshop had a total of 25 students, with 21 participating in the research. A pilot workshop for teachers was organized in May 2023 within the project titled “Support of internal systems for ensuring the quality of higher education at the University of Ss. Cyril and Methodius in Trnava, Slovakia”, with 25 university teachers participating (21 of whom took part in the survey). The research results indicate that both students and teachers perceive design thinking as a suitable method for the current educational process. Students identified presentation skills as their biggest challenge, whereas teachers did not face significant issues in this area due to their profession. Conversely, teachers expressed difficulties with digital skills, which were less prevalent among the students. Design thinking offers numerous benefits to students by creating a supportive learning environment. Additionally, for teachers, this method can become a part of their lifelong learning, as innovation relies on their motivation and efforts to teach traditional content differently.

Guest Editorial: Solar Energy Utilization

Guest Editorial: Solar Energy Utilization

Peer Review Statement

All papers published in this volume have been reviewed through processes administered by the Editors. Reviews were conducted by expert referees to the professional and scientific standards expected of a proceedings journal published by IOP Publishing Publishing.1. Type of peer review: Single anonymous2. Conference submission management system: Morressier3. Number of submissions received: 404. Number of submissions sent for review: 175. Number of submissions accepted: 166. Acceptance Rate (Submissions Accepted / Submissions Received × 100): 40.0 %7. Average number of reviews per paper: 2.358. Total number of reviewers involved: 359. Contact person for queries:Name: Mária BehúlováAffiliation: Slovak University of Technology in Bratislava, Faculty of Materials Science and Technology in Trnava, Jána Bottu 2781/25, 917 24 Trnava, Slovak RepublicEmail: maria.behulova@stuba.sk* means value has been edited

Preface

ICIR Euroinvent 2021 International Conference on Innovative Research in the field of Materials Science and EngineeringMay 20th to 21st, 2021Iasi – Romania Organized by: • Romanian Inventors Forum • Faculty of Materials Science and Engineering, The “Gheorghe Asachi” Technical University of Iasi, Romania • ARHEOINVEST Platform, Alexandru Ioan Cuza University of Iasi • Centre of Excellence Geopolymer and Green Technology CEGeoGTech), Universiti Malaysia Perlis (UniMAP) • Department of Physics, Czestochowa University of Technology, Częstochowa, Poland List of With support of, Editor, Foreword, Scientific Advisory Board, Chairman, Event Coordinator, Technical and Organizing Committee are available in the pdf

Voice frequency impact for voice control of collaborative robots

The project is focused on research of voice control of collaborative robots. Previous research of voice control and speech recognition research have given examples and evidence that machines can truly be controlled by human voice. The main problem in the voice control of collaborative robots is the lack of reliability and safety of control compared to manual control. Of the results achieved, the most and least relevant voice control problem has been clearly identified, next step is voice frequency impact for voice control. The experiments were performed in the robotics laboratory at the Faculty of Materials Science and Technology in Trnava, and this using an Arduino kit and a small robot “DOBOT Magician“. In the final part of the project are summarized all experimentally found facts and confronted with the assumptions set in the design of the experiment.

Deformability Tests of Pure Niobium

A research team at the University of Miskolc’s Faculty of Materials Science and Technology has signed a cooperation agreement with the Geneva-based European Organization for Nuclear Research (CERN) for testing of the materials employed in the Crab Cavities will be installed in the next generation of the LHC (the so-called High Luminosity Large Hadron Collider – HL-LHC). At the University of Miskolc, high purity niobium rolling experiments were carried out in conventional (unidirectional) and cross-rolled manners in order to increase the deep drawability of the final sheet. The deformability of niobium was measured by Watts-Ford and compression tests. The microstructure and anisotropy (texture) results of the initial material and the straight-rolled products are reported.

How Millennials Affect Corporate Culture

Abstract Corporate culture is made by the company´s employees. However, their age composition is different and is members of different generations that interact. Every generation brings with it something new, not only positive but also negative. Therefore, each generation should work together to eliminate the negative aspects and highlight the benefits of each generation and exploit them to their advantage. Each of the generations influences the corporate culture in different ways. The aim of the paper is to point out the results of research, which was realized at Faculty of Materials Science and Technology in Trnava and focused on individual generations of employees. We draw attention especially to the Generation Z, its impact on corporate culture and the new “wind” that it brings. This paper was written on the basis of research results of VEGA project No.1/0348/17 “The impact of the coexistence of different generations of employees on the sustainable performance of organisations”.

Zastosowanie nieradialnego modelu SBM z ograniczeniami wag do pomiaru efektywności dydaktycznej w szkolnictwie wyższym

Objective: The article measures the efficiency of higher education didactic activities using a non-radial SBM model with weight restrictions. The analysis was performed on two levels, from the analysis of 59 public higher education institutions in Poland and 18 faculties of the Warsaw University of Technology in 2014.Research Design & Methods: A non-radial SBM model with weight restrictions (Slack Based Measure Assurance Region, SBM-AR) was used to assess efficiency.Findings: The results of the study indicate that, irrespective of the research assumption, only the Jagiellonian University in Kraków, Gdańsk University of Technology and Wrocław University of Technology, in the case of universities, and the Faculty of Electronics and Information Technology and the Faculty of Materials Science at the Warsaw University of Technology proved to be fully efficient units in all models and research approaches. Eight universities and three faculties were not fully efficient, though they were efficient in some respects.Implications / Recommendations: Imposing restrictions on the SBM weights made it possible to reduce the excess number of efficient universities present in the classical approach.Contribution: The study proves that adopting the appropriate DEA model determines the results of unit efficiency. Therefore, different models should be used in conjunctions with a comprehensive performance assessment based on them.

Development of Modern Fundamental Materials Science at the Faculty of Materials Science of the Moscow State University

The key families of modern materials and the evolution of promising materials research trends, which has entered an active phase in the 1990s, are reviewed. It is noted that the classical approaches to materials engineering centered on revealing and utilizing correlations between the composition, the structure, and the properties should be complemented by a thorough analysis of the actual structure and the structure-sensitive characteristics of materials; careful consideration of the synergy of external effects in material synthesis and the possibilities provided by template synthesis, self-assembly, and self-organization in nanomaterials engineering; and the examination of response of living systems to biomaterials. Being highly interdisciplinary, fundamental materials science borrows heavily from modern inorganic chemistry, physical chemistry, and solid-state chemistry, which invariably guide the development trends in materials science.

Status of Ion Beam Modification and Analysis of Materials at STU MTF

Abstract The new Ion Beam Centre (IBC) equipped with 6 MV tandem ion accelerator and 500 kV ion implanter systems was built at the Slovak University of Technology, Faculty of Materials Science and Technology (STU MTF). The facility provides Ion Beam Modification of Materials (IBMM) and Ion Beam Analysis (IBA), which includes Rutherford Backscattering Spectrometry (RBS), Particle Induced X-ray Analysis (PIXE), Elastic Recoil Spectrometry (ERDA) and Nuclear Reaction Analysis (NRA). Presented are selected experimental procedures carried out in the IBC during the first year of operation. They present examples of a typical IBA performed, such as thin film characterisation in nm to tens of µm range, elemental depth profiles and sensitivity to the light elements enhancement by non-Rutherford cross-section regime application along with the crystalline sample channelling spectra and boron content measurement.

Wear of Cutting Tool with Excel Geometry in Turning Process of Hardened Steel

Abstract This paper deals with hard turning using a cutting tool with Xcel geometry. This is one of the new geometries, and there is not any information about Xcel wear in comparison to the conventional geometry. It is already known from cutting tools producers that using the Xcel geometry leads to higher quality of machined surface, perticularly surface roughness. It is possible to achieve more than 4 times lower Ra and Rz values after turning than after using conventional geometry with radius. The workpiece material was 100Cr6 hardened steel with hardness of 60 ± 1 HRC. The machine used for the experiment was a lathe with counter spindle DMG CTX alpha 500, which is located in the Centre of Excellence of 5–axis Machining at the Faculty of Materials Science and Technology in Trnava. The cutting tools made by CBN were obtained from Sandvik COROMANT Company. The aim of this paper is to investigate the cutting tool wear in hard turning process by the Xcel cutting tool geometry.

Real Time Monitoring and Automatic Regulation System for Metalworking Fluids

Abstract A real-time monitoring and regulation system for metalworking fluids is being constructed to be installed in the Centre of excellence of 5-axis machining at the Faculty of Materials Science and Technology in Trnava. The article is focused on the description of the main components of the monitoring system and preliminary characterization of the software utilized in the regulation. The monitoring system will contain four probes to record real time values of pH, conductivity, temperature and concentration. After processing of recorded data by the LabVIEW software, an adjustment of the Metalworking fluid in the reservoir tank will be realized by the regulation part of the proposed system to optimum properties of the fluid, by adding water or concentrate. The designed device will provide an easy system which will control the quality of used metalworking fluid during its lifetime and maintain it on its optimum condition without human operator’s assistance.

Influence of Surface Modification Methods on the Topography of Dental Implants by Using Metrological Observation Techniques

Influence of Surface Modification Methods on the Topography of Dental Implants by Using Metrological Observation Techniques A.G. Bulutsuza,∗, C.U. Mercan, G. Karapinar, A.B. Katiboglu and M. Lewandowska Yildiz Technical University, Faculty of Mechanical Engineering, Department of Mechanical Engineering, 34349, Istanbul, Turkey Istanbul Aydin University, Department of Oral and Maxillofacial Surgery, 34088 Florya, Istanbul, Turkey Istanbul University, Faculty of Dentistry, Department of Oral and Maxillofacial Surgery, 34093, Istanbul, Turkey Warsaw University of Technology, Faculty of Materials Science and Engineering, Warsaw, Poland

Producing and characterizing PCL/PA6 three dimensional nanofibrous scaffolds for tendons and ligaments regeneration

Event Abstract Back to Event Producing and characterizing PCL/PA6 three dimensional nanofibrous scaffolds for tendons and ligaments regeneration Chiara Rinoldi1, Ewa Kijeńska1 and Wojciech Swieszkowski1 1 Warsaw University of Technology, Faculty of Materials Science and Engineering, Poland Regenerative medicine is an interdisciplinary field that applies the principles of engineering and biology to develop biological substitutes to repair, replace or improve the cell functions, tissues or organs, damaged by congenital defects, trauma or aging. Three-dimensional scaffold systems promote cell growth and proliferation, providing a physiological and mechanical environment suitable for cell culture. Scaffold materials should mimic the native extracellular matrix (ECM) and its complex features, enhance fluid transport within the matrix (O2 and nutrients) and favor the disposal of metabolic wastes. The aim of this work is to design and fabricate 3D biodegradable electrospun nanofibrous structures, which can provide adequate environment and bio-signals for cells. Polycaprolactone (PCL) and Polyamide 6 (PA6) were selected to produce the scaffold, due to their biocompatibility, slow degradability, non toxicity and high mechanical properties. The polymers blends were dissolved in an innovative dissolvent system composed by Acetic acid and Formic acid, which are less toxic than the common organic solvents used for PCL dissolution. The overall scaffold architecture, its structure at micro and nanoscale, its chemical composition and mechanical properties were optimized. The control of the degradation kinetics and the homogeneous cell distribution was investigate to guarantee a successful therapy. The results of this study suggest that the PCL/PA6 nanofibrous scaffold might be interesting alternative for tendons and ligaments regeneration. This study was supported by the National Center for Research and Development (STRATEGMED1/233224/10/NCBR/2014, project START). Keywords: nanofiber, Tissue Regeneration, 3D scaffold, Biodegradable material Conference: 10th World Biomaterials Congress, Montréal, Canada, 17 May - 22 May, 2016. Presentation Type: Poster Topic: Regenerative medicine: biomaterials for control of tissue induction Citation: Rinoldi C, Kijeńska E and Swieszkowski W (2016). Producing and characterizing PCL/PA6 three dimensional nanofibrous scaffolds for tendons and ligaments regeneration. Front. Bioeng. Biotechnol. Conference Abstract: 10th World Biomaterials Congress. doi: 10.3389/conf.FBIOE.2016.01.02858 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 27 Mar 2016; Published Online: 30 Mar 2016. Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Chiara Rinoldi Ewa Kijeńska Wojciech Swieszkowski Google Chiara Rinoldi Ewa Kijeńska Wojciech Swieszkowski Google Scholar Chiara Rinoldi Ewa Kijeńska Wojciech Swieszkowski PubMed Chiara Rinoldi Ewa Kijeńska Wojciech Swieszkowski Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Development of drug-releasing shape-memory polyurethane/hydroxyapatite composites - smart biomaterial for bone tissue implants

Event Abstract Back to Event Development of drug-releasing shape-memory polyurethane/hydroxyapatite composites - smart biomaterial for bone tissue implants Monika Bil1, Marcin Heljak1 and Wojciech Swieszkowski1 1 Warsaw University and Technology, Faculty of Materials Science and Engineering, Poland Introduction: Shape-memory polymers (SMPs) are mechanically active or smart materials, which can be deformed and fixed in a temporary shape and are able to return to their original, permanent shape when exposed to a suitable external stimulus. The unique attributes of shape memory effect in conjunction with biodegradability and drug delivery present enormous opportunities for the design of next generation, resorbable less invasive self-fitting medical implants, tissue scaffolds and medical devices[1]-[3]. The ultimate goal of the study is to develop self - deploying drug delivery system for bone tissue regeneration utilizing thermoplastic SMPs which could self-fitting to a target tissue defect and ensure a local drug release at the site of administration. Materials and Methods: Hydroxyapatite/polyurethane (HA/PU) composites were synthesized through in-situ polymerization with biodegradable hydroxyl terminated oligomers of polycaprolactone and poly(lactide-co-glycolide), 1,6-hexamethylene diisocyanate as a coupling agent and dibutyltin dilaurate as the catalyst. HA nanoparticles (Merck) and gentamicin sulfate (GS) ( 5% wt.) ultrasonically dispersed in dehydrated tetrahydrofuran (THF) were added to synthesis mixture. Chemical structure of the composites were analysed by Raman spectroscopy. Drug release study were performed in vitro in PBS and analyzed using UV spectrophotometer at a wavelength of 332 nm. Shape memory behavior was analyzed in thermomechanical test by dynamic mechanical analyzer (DMA) in water. The shape recovery ratio Rr and the fixity ratio Rf were calculated based on DMA measurement. The relationship between amounts of HA, drug content and shape memory properties were analyzed. Results and Discussion: A series of thermoplastic nano-HA/PU/GS composite with the content of HA in the range 3, 5 10 wt. % were synthesized. Quantitative assessment of the shape memory performance through thermomechanical shape memory cycles verified that all materials exhibited a shape-fixing ratio Rf from 80% to 85% and shape recovery ratio (Rr 80-100%). The best shape recovery ability Rf -100% in water at 37oC was observed for composite with 3% wt. of HA. The shape recovery ratio decreased slightly with an increment in HA nanoparticles weight fraction, due to formation of agglomerates that could be a hindrance in recovery of the macromolecule structure. In order to evaluate the effect of shape recovery on drug release profile the drug release study were performed for the samples subjected thermomechanical shape memory cycle. The results revealed sustained drug release over two weeks. However, initial burst release increased with increasing of HA weight fraction what could be connected with easier water penetration into polymer matrix through HA nanoparticles polymer matrix interface. Conclusion: We successfully prepared series of thermoplastic PU/HA composites based on biodegradable oligoesters combining controlled drug release and shape memory effect. All the drug-loaded samples have satisfactory shape memory properties with shape recovery within body relevant temperature, and drug release behavior, therefore appear to be potentially useful for biomedical applications. The authors would like to thank the National Centre for Research and Development (Grant no: LIDER/037/673/L-4/12/NCBR/2013) for providing financial support to this project

Core-shell polyurethane nanofibers with shape memory for drug release applications

Event Abstract Back to Event Core-shell polyurethane nanofibers with shape memory for drug release applications Ewa Kijeńska1, Monika Bil1, Mariusz Uchman2 and Wojciech Swieszkowski1 1 Warsaw University of Technology, Faculty of Materials Science and Engineering, Poland 2 Charles University in Prague, Faculty of Science, Czechia Introduction: Coaxially electrospun polymeric nanofibers are promising carriers for versatile bio-active agents, growth factors and drugs, allowing for their control release. On the other hand shape memory polyurethanes have excellent thermal shape memory effect and demonstrate high biocompatibility. Thus recently core-shell nanofibers based on this kind of polymers have gained much attention in various biomedical applications like cardiovascular stents. In this study preliminary investigation of electrospun fibers made of polyurethane and polyurethane/gelatine with encapsulated microspheres towards drug release and shape memory was performed. Materials and Methods: Polyurethane PCL/PLLA with shape memory based on PCL and PLLA was synthesized by polymerization in our laboratory. PCL-PEO nanoparticles ere prepared according to the protocol: 10mg of each copolymer was added to 90% THF/water mixtures and left shaken overnight till full dissolution copolymers was achieved. Then solutions were added drop-by-drop to water under vigorous stirring. Finally the solutions were dialyzed against water. In our experiments, for comparison, core –shell fibers with PCL/PLLA; PCL/PLLA:Gelatin [90:10], PCL/PLLA:Gelatin [80:20] in HFP as a shell and microspheres in water as a core, were prepared using the co-axial electrospinning. Results and Discussion: Electrospun uniform and bead free fibrous structures were successfully fabricated using co-axial electrospinning. SEM micrographs (Fig.1) of electrospun mesh revealed porous, beadless, fibrous topography. TEM investigation confirmed core-shell character of obtained fibers. Contact angle measurements data supported the fact that the incorporation of gelatin made meshes more hydrophillic compared fibers with pure polyurethane shell, thus more sufficient for biomedical applications. Release studies showed potential of use of this types of fibers for encapsulation of the drug loaded microspheres. Conclusions: Our studies suggest the potential application of co-axially electrospun PCL/PLLA polyurethane fibrous carriers with encapsulated drug loaded microspheres as a suitable substrate for target tissue engineering and indicate co-axial electrospinning technique as a promising method for fabrication of polyurethane fibers with improved functionality. The authors would like to thank the National Centre for Research and Development (Grant no: LIDER/037/673/L-4/12/NCBR/2013) for providing financial support to this project. Keywords: nanofiber, Polymeric material, medical application, Biofunction Conference: 10th World Biomaterials Congress, Montréal, Canada, 17 May - 22 May, 2016. Presentation Type: Poster Topic: Electrospinning and related technologies Citation: Kijeńska E, Bil M, Uchman M and Swieszkowski W (2016). Core-shell polyurethane nanofibers with shape memory for drug release applications. Front. Bioeng. Biotechnol. Conference Abstract: 10th World Biomaterials Congress. doi: 10.3389/conf.FBIOE.2016.01.02867 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 27 Mar 2016; Published Online: 30 Mar 2016. Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Ewa Kijeńska Monika Bil Mariusz Uchman Wojciech Swieszkowski Google Ewa Kijeńska Monika Bil Mariusz Uchman Wojciech Swieszkowski Google Scholar Ewa Kijeńska Monika Bil Mariusz Uchman Wojciech Swieszkowski PubMed Ewa Kijeńska Monika Bil Mariusz Uchman Wojciech Swieszkowski Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

The effect of drug loading technics on in vitro release profile from multifunctional chitosan/polyurethane composites.

Event Abstract Back to Event The effect of drug loading technics on in vitro release profile from multifunctional chitosan/polyurethane composites. Aleksandra J. Kucharska1 and Monika Bil1 1 Warsaw University of Technology, Faculty of Materials Science and Engineering, Poland Introduction: The concept of multifunctional devices that combine drug eluting components together with functional prosthetic implants, represents an emerging clinical technology that promises to provide functional enhancement to implant devices in various clinical applications[1],[2]. The properly designed drug delivery system can allow for a precise drug release control, which refers to the amount of released dose, the drug release profile and the speed of release[3]. In general, the choice of the proper drug loading technic can be decisive for obtaining the suitable and desired drug release from biomaterial[4]. The aim of this work was to compare different methods of the drug loading into chitosan/ polyurethane matrix in terms of optimization of the developed systems. Materials and Methods: In the first stage chitosan microspheres were prepared using emulsification/cross-linking method[5]. Chitosan solution in acidic acid containing gentamicin (3 or 6 wt. % vs. chitosan mass) was emulsified in the dispersion medium consisting of liquid paraffin stabilized by the sorbitan monooleate. Triphosphate pentasodium (TPP) and glutaraldehyde (25 or 50 wt.% solution in H2O) were used as a cross-linking agents. Next the microspheres loaded with gentamicin were added to the synthesis of polyurethane matrix (PU). PU networks based on three-branched hydroxyl terminated caprolactone (CL) and glycolide-co-lactide (PLGA) oligomers were synthesized using 1,6-hexamethylene diisocyanate (HMDI) and dibutyltin dilaurate as the catalyst. Additionally, polyurethanes consisting of chitosan macromolecule segment were synthesized and drugs were incorporated directly into the polymer matrix during synthesis. In vitro release study was performed after immersion of the composites in PBS according to the method used by Zang[6]. Results and Discussion: Two types of biodegradable polyurethane composites containing chitosan microspheres or chitosan macromolecule segments were obtained. Chitosan microspheres with mean diameter of 8 μm (Fig.1) were distributed within polymer matrix. Drug loading efficiency in case of microspheres system increased significantly form 3% for microspheres crosslinked with 50 wt.% glutaraldehyde to 60% for microspheres crosslinked with 25 wt%. glutaraldehyde. Drug release profile from the gentamicin containing-microspheres composites proved to be stable and sustained for more than a month (Fig. 2.). In case of the polyurethane composites containing the microspheres with the drug loaded directly to the polymer matrix, the higher burst release was observed due to the facilitated diffusion of the drug. Conclusion: The results of drug release study showed that the drug release kinetics from the chitosan/polyurethane composites system can be modified by drug loading method and the cross-linking degree of chitosan microspheres. The study confirms that these systems could be successfully used un regenerative medicine as drug carriers. This work was financed by National Science Centre on the basis of a decision number DEC- 2012/07/D/ST8/02588.

New approach for porous materials obtaining using centrifugal casting

It has been presented different methods for obtaining porous materials, (mainly used for metallic foams) and highlighting a new technology developed in the Faculty of Materials science and engineering, of Iasi. Our technology for obtaining porous materials is called centrifugal casting for porous materials. This technology is included in the method number 8: co-pressing of a metal powder with a leachable powder being in the same time a newer approach in the porous materials field. This technology is currently in the developmental phase. Since now we made experiments on the metallic materials, aluminum alloys. The technology is briefly described in this paper. The obtained parts were used for making samples in order to characterize the properties of the materials. The cellular structure of metallic foams requires special precautions that must be taken in characterization and testing. In this paper we have characterized the samples structurally by its cell topology (open cells, closed cells), relative density, cell size and cell shape and anisotropy. Also it was used scanning electron microscopy (SEM) which is straightforward; the only necessary precaution is that relating to surface preparation.