Materiale Plastice Vol 54, Issue 4

Volume 54, Issue 4

Published: December 2017 Articles: 42 Pages: 601 – 805
Research Articles
601 – 605
Statistical Analysis of Some Mechanical Characteristics of Glass Fiber Reinforced Composites
PAULINA SPANU, CATALIN GHEORGHE AMZA, GABRIELA DINU
Open Access DOI: 10.37358/MP.17.4.4908
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Abstract: This paper presents the results of the experimental researches obtained in the three-point test of the glass-fiber-reinforced polymeric composites. Mathematical modeling of experimental results was performed using a virtual instrument (VI) developed in the graphical programming language called LabVIEW. In order to process the experimental data and display the results, the virtual instrument (VI) allows both the reading of experimental data from a saved text file from the same folder as the current VI file and the direct entry of experimental values into a control element disposed on its front panel. The virtual instrument described in this article is part of a more complex project used for the mathematical modeling of the experimental data obtained in determining the physic-mechanical characteristics of glass fiber randomly reinforced polymeric composites.
606 – 609
Investigating the Deformation Parameters of PVC Fitness Balls in Relation to the Height and Body Mass Index of the Users
FLAVIU STELIAN DUSA, ADELA BADAU, DANA BADAU, CRISTIAN TRAMBITAS, KLARA BRINZANIUC
Open Access DOI: 10.37358/MP.17.4.4909
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Abstract: The aim of the study was to measure the goniometric differences of the knee and hip joints and the changes regarding the features of fitness balls by taking into consideration its circumference and the vertical and horizontal diameters under the action of the body weight. The outcomes of the study have resulted in the creation of a table with reference values regarding the size of fitness balls in relation to the height and body mass index of the subjects.
610 – 615
Comparative Analysis of Two Bioplasticizers Used to Modulate the Properties of PLA Biocomposites
Maria RAPA, Raluca Nicoleta DARIE NITA, Anamaria IRIMIA, Morten SIVERTSVIK, Jan Thomas ROSNES, Ancuta Roxana TRIFOI, et al.
Open Access DOI: 10.37358/MP.17.4.4910
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Abstract: The present paper deals with a comparative study on the influence of two different bioplasticizers: acetyl tributylcitrate (ATBC) and LAPOL108 on the mechanical and antimicrobial properties of poly(lactic acid) PLA containing 1 wt.% chitosan. PLA based biocomposites were investigated by means of processing behavior, FT-IR spectroscopy, DSC analysis, tensile and barrier properties, migration in food simulants and antifungal activity. Based on the obtained results it can appreciated that the properties of the PLA based biocomposites could be appropriate for designing flexible or rigid food packaging depending of the bioplasticizer used.
616 – 619
Mechanical Stress Exploration Inside of Dental Filling Materials by Means of Electronic Speckle Pattern Interferometry / Shearography
ALINA ORMENISAN, DANIEL TAMAS SZAVA, IOAN SZAVA, CIPRIAN DALAI
Open Access DOI: 10.37358/MP.17.4.4911
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Abstract: Possible causes of microleakage and microfractures of dental fillings are often in the center of many academic research and investigations. Some authors found that one important cause of microleakage is the contraction/ shrinkage of the filling materials during polymerization. The purpose of this study is to demonstrate that microcracks and consequent microleakage is influenced by mechanical stresses occurring inside of dental filling materials and at the interface of the dental cavities and dental filling materials. We also tried to evaluate the deformation of some dental filling material types during mechanical loading. Cylindrical specimens were made of different types of dental filling materials, namely microhybrid composites and glass ionomer cement. Some extracted teeth were prepared with class II cavities, and filled. The lateral swelling of the tested specimens and the deformation of the filled teeth during vertical axial loading was measured with an optical method, ESPI/ Shearography.Of the tested specimen, the least deformable dental filling materials were the composite materials. During occlusal vertical loading of the filled teeth, there were found that mechanical stresses were different inside of the filling material than inside of the walls of the dental tissues, mechanical stressed being concentrated at the restoration interface. The ESPI/Shearography meth ode proved to be very useful for investigation in this field. Due to mechanical stresses accumulating at the interface of the dental filling material and the walls of the dental cavity, it is possible that later microcracks to appear due to masticatory forces.
620 – 625
In vitro Testing of Experimental and Commercial Bracket Bonding Materials
Anca S. Mesaros, CRISTIAN ROMANEC, MICHAELA MEZAROS, Marioara Moldovan, Ioana Baldea
Open Access DOI: 10.37358/MP.17.4.4912
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Abstract: The aims of our study were to assess the cytotoxic effect of five orthodontic bonding materials, in vitro, on HUVECs to study the induction of apoptosis and inflammatory response generated to assess the shear-bond strength of the 5 tested materials in order to quantify their performance. Standardized samples from each material were obtained and incubated with HUVEC cells for 24 and 72 h immersed in complete medium. Cell viability was determined by means of MTS method. Active caspase 3 and TNFa protein levels were measured through ELISA techniques. The shear-bond strength was tested on 60 extracted premolars which were bonded with the same type of bracket, using the 5 different materials. Statistical analysis Student T-tests, Chi-square and Anova tests were used for results interpretation. Cell viability was decreased with material exposure in a time dependent manner. All materials exerted cytotoxic effects, the experimental materials showed a significantly higher decrease in cell viability at the 72 h reading. Shear Bond strength was superior for the resin commercial bracket-bonding materials. The study shows that orthodontic adhesives’ cytotoxicity and physical performance is related to their chemical properties and proves that all orthodontic practitioners should use freely their material of choice on condition they are aware of all its’ properties.
626 – 629
The Use of Polypropylene Mesh in the Reconstruction Techniques of the Thoracic Wall After Resections of the Thoracic Wall
BOGDAN ANDREI SUCIU, IOANA HALMACIU, VASILE BUD, CONSTANTIN COPOTOIU, DECEBAL FODOR, CRISTIAN TRAMBITAS, et al.
Open Access DOI: 10.37358/MP.17.4.4913
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Abstract: The thoracic wall resections for tumoral affections are laborious surgical interventions characterized by a high mortality and mobility. In order to create this paper we created a observational retrospective study in which we included 21 patients that have underwent parietal thoracic resections for tumoral affections. In all the patients we practiced the reconstruction of the thoracic wall using polypropylene mesh. The main postoperative complications were: seromas (14.28% of the cases), hematomas (9.52% of the cases), wound infection (4.76% of the cases), pneumonia (23.8% of the cases), respiratory failure (23.8% of the cases), paradoxical movement of the thoracic wall (52.38% of the cases). No deceases were recorded. In conclusion, the use of polypropylene mesh in the reconstructive techniques of the thoracic wall after thoracic wall resection represents a viable method, with good respiratory functional results.
630 – 634
The Effects of Magnetic Nanoparticles Incorporated in Polyelectrolyte Capsules
Carmen Stavarache, Mircea Vinatoru, Timothy Mason, Larysa Paniwnyk
Open Access DOI: 10.37358/MP.17.4.4914
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Abstract: Polyelectrolyte multilayer capsules are synthesized comprising of 12 total layers each containing a single layer of iron oxide nanoparticles in shells 4, 6, 8 or 10. A protein-labelled dye is embedded in the calcium carbonate template core as a model for the encapsulation of a drug. The core is dissolved after 6 layers are formed. Two types of magnetic nanoparticles are incorporated into various capsule shells: ferric oxide (Fe2O3, 50 nm) and iron oxide (Fe3O4, 15 nm), a 1:1 (vol.) mixture of the two types of nanoparticles suspensions is also used. Nanoparticle inclusion reduces the capsule sizes in all cases with the order of effect Fe3O4 [ Fe2O3 [ Fe2O3/Fe3O4 mixture. When Fe3O4 or a Fe2O3/Fe3O4 mixture is incorporated in layer 6 the reduction in size of the final capsules is less than expected. The number of surviving capsules containing nanoparticles are lower than control regardless of which of the nanoparticles is used but here the effect of Fe3O4 or a mixture of the two types of nanoparticles incorporated in layer 6 was slightly out of step. The amount of iron incorporated is almost the same regardless of which shell the nanoparticles were incorporated but the iron content using 50 nm nanoparticles is generally slightly higher than that obtained with 15 nm nanoparticles.
635 – 638
Polypropylene Mesh in Minimally Invasive Treatment of Female Stress Urinary Incontinence
Nicolae Grigore, Valentin Pirvut, Ionela Mihai, Adrian Hasegan, Elisabeta Antonescu, Liliana Coldea, et al.
Open Access DOI: 10.37358/MP.17.4.4915
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Abstract: Stress urinary incontinence in women is a condition widely encountered in the entire world with a prevalence between 12.8% and 46.0%. Stress urinary incontinence is a public health problem causing a significant decrease in quality of life, involving social, physical, psychological, occupational and sexual suffering of patients. The minimal invasive treatment of the stress urinary incontinence (SUI) consists in fixing a suburethral polypropylene mesh (SPM) in retropubic (TVT) or transobturator (TOT) space, in order to regain the pelvic support of the urethra, with the consecutive augmentation of the pressure of urethral closing during effort. The objective of this paper is to present the advantage of SPM in the SUI treatment in the eleven years’ experience of Department of Urology Sibiu.
639 – 644
Experimental Research on the Triangular Lattice Type Polymer Based Composites Structures for Sandwich Panels Construction
Adrian Costin DURBACA, RADU IATAN, Ion DURBACA, Alin DINITA, Marius VASILESCU
Open Access DOI: 10.37358/MP.17.4.4916
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Abstract: The paper presents experimental results on the mechanical behaviour for a polymer based composite sandwich panel tensile and bending tested, which uses, one by one, a cellular composite core fabricated by additive manufacturing of four different types of polymeric materials: ABS (acrylonitrile butadiene styrene), PC (polycarbonate), PLA (polylactide) and CF (polylactide + 40% carbon fibre), with the thickness of 3 and 5 mm. This research focuses on comparative analysis of the core thickness increase effect on the structure’s strength. Experimental tests carried out on standardized test-pieces with specialized laboratory equipment, are highlighting similar mechanical behaviour and are showing also an increase of composite stiffness with the increase of core thickness, at the same time, the arrangement of the cellular lattice structure has a significant effect on the structural strength.
645 – 647
The Effects of Magnetic Nanoparticles Incorporated in Polyelectrolyte Capsules
Corneliu Druga, Radu Necula, Diana Cotoros, Roxana Miclaus, Angela Repanovici, Sarah Adriana Nica
Open Access DOI: 10.37358/MP.17.4.4917
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Abstract: Most studies and experimental tests performed upon orthopaedic bone cements are related to their use in everyday conditions when usual wears are due to compression and fatigue. The present paper deals with some special situations occurred during the patient’s recovery after the surgery. The recovery activities and motions may induce different types of loads, like tensile, during stretching and relaxation techniques, especially in the joint insertion area. These situations are insufficiently researched, but they represent one of the main concerns of the medical staff involved in recovery and rehabilitation. Besides the study of mechanical properties for these special situations the paper proposes also a thermal analysis during preparation of the polymethylmethacrylate(PMMA) as it can be the trigger of serious health issues (necrosis, blood circulation problems, BCIS, etc.) due to the exothermic polymerization reaction. The monitoring method proposed for the temperatures developed during the polymerization may avoid the aforementioned issues.
648 – 650
Innovative Poly Methyl Acrylate Intubation Device Used in Difficult Airway Instrumentation of Patients with Pharyngeal Tumors
Razvan Hainarosie, Narcis Tanase, Viorel Zainea, Catalina Pietrosanu, Irina Ionita, Dragos Cristian Stefanescu
Open Access DOI: 10.37358/MP.17.4.4918
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Abstract: Difficult airway management is a common situation when the anesthesiologist deals with patients with hypo pharyngeal tumors. The volume of the tumor usually covers the glottis plan and modifies the local anatomy, making the intubation process difficult or almost impossible. Intubation laryngoscopes developments are minor and adding a CCD camera at the tip of the laryngoscope is the best improvement made in our days. Today, on the market, an intubation device designed properly for the patients with extensive hypo pharyngeal tumors does not exist. The aim of the paper is to present an innovative device designed for patients with hypo pharyngeal tumors.
651 – 654
Synthesis and Physico-Chemical Evaluation of Polyurethane Microstructures for Transmembrane Delivery of Reynoutria japonica Extract
FLORINA Ardelean, RAZVAN SUSAN, FLORIN Borcan, ALINA Moaca, DIANA SIMONA Antal, CODRUTA Soica, et al.
Open Access DOI: 10.37358/MP.17.4.4919
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Abstract: Polymer microstructures containing plant extracts are a novel technique used to increase the bioavailability of active agents with low aqueous solubility. Japanese knotweed (Reynoutria japonica) is an invasive plant with multiple biomedical properties. The aim of the present study was to obtain and characterize polyurethane microstructures used as a drug delivery system of a Japanese knotweed extract. The results indicate the obtaining of microstructures with an almost neutral pH, with sizes between 540 and 1134 nm, with a medium stability against the tendency to form clusters and a very good thermal stability. These first results present the potential of the obtained polyurethane microstructures as candidates for the transmembrane drug delivery of Japanese knotweed extracts, as a starting point for further bioactivity investigations.
655 – 658
Low Molecular Weight Microfibers with Light Sensing Properties
Andrei Bejan, Dragos Peptanariu, Bogdan Chiricuta, Elena Bicu, Dalila Belei
Open Access DOI: 10.37358/MP.17.4.4920
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Abstract: Microfibers were obtained from organic low molecular weight compounds based on heteroaromatic and aromatic rings connected by aliphatic spacers. The obtaining of microfibers was proved by scanning electron microscopy. The deciphering of the mechanism of microfiber formation has been elucidated by X-ray diffraction, infrared spectroscopy, and atomic force microscopy measurements. By exciting with light of different wavelength, florescence microscopy revealed a specific optical response, recommending these materials for light sensing applications.
659 – 665
Fabrication of Novel Silk Fibroin - LDHs Composite Arhitectures for Potential Bone Tissue Engineering
Bianca Galateanu, Ionut Cristian Radu, Eugenia Vasile, Ariana Hudita, Mirela Violeta Serban, Marieta Costache, et al.
Open Access DOI: 10.37358/MP.17.4.4921
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Abstract: Nanocomposite materials have attracted a high interest for biomedical applications because their special properties related with structure and composition. In this paper we synthesized novel hydrogel nanocomposite materials special designed for hard tissue engineering. The nanocomposite materials are able to promote hydroxyapatite formation by alternating soaking mineralization demanded for increasing of cells biocompatibility and adhesion.
666 – 672
On Physical and Chemical Characteristics of Poly(methylmethacrylate) Nanocomposites for Dental Applications. I.
Eugenia Eftimie Totu, CORINA MARILENA CRISTACHE, ELENA VOICILA, OVIDIU OPREA, Ismail Agir, Ozlem Tavukcuoglu, et al.
Open Access DOI: 10.37358/MP.17.4.4922
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Abstract: The objective of this paper is to present the thermal behavior of various PMMA/TiO2 nanocomposite for complete dentures fabrication with 3D printing technology. There have been prepared and thermally characterized polymeric composites with varied nanofiller content ranging between 0.2% and 2.5% (w/w%). The nanocomposites proved a better thermal performance than that of pure copolymer PMMA-MMA or 3D printing PMMA polymer complex matrix. A small difference in glass transition (Tg) temperature for all compounds studied was recorded.
673 – 677
Polylactic Acid/Cellulose Fibres Based Composites for Food Packaging Applications
Elisabeta Elena Popa, Maria RApA, Ovidiu Popa, Gabriel MustATea, Vlad Ioan Popa, Amalia Carmen Mitelut, et al.
Open Access DOI: 10.37358/MP.17.4.4923
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Abstract: PLA-based composites containing CF in the range 0 to 10 wt. % were prepared by melt mixing technique. The prepared composites were investigated in terms of processability, chemical structure (by Attenuated total reflectance - Fourier Transform Infrared - ATR-FT-IR analysis), thermal (Differential Scanning Calorimetry - DSC), optical properties (using UV-Vis spectrometry), barrier and migration in distilled water. Also, the behaviour of PLA based composites at sterilization was performed by examination the changes in their chemical structure. This study shows the feasibility of improving of PLA properties by using cellulose fibres, designed for flexible food packaging.
678 – 681
Macroscopic Examination of Placental Vascularization with a Corrosive Agent in Pregnant Women Diagnosed with Thrombophilia
Diana Camelia Bonte, Olivera Iordache, Izabella Petre, Marius Craina, Veronica Daniela Chiriac, Dana Stoian, et al.
Open Access DOI: 10.37358/MP.17.4.4924
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Abstract: The normal development of the placenta is a major factor in the fetus’s growth and development, whilst the maternal-fetal placental vasculature is essential in this regard. During placentation, there is an ongoing process, which combines angiogenesis with vasculogenesis, as demonstrated by numerous studies, which reveal important roles of various known angiogenic factors, while other studies show the roles of different classes of factors in vascular morphogenesis nonspecific to the placenta. The method used in the case of our study is a standardized method of the Laboratory of Anatomy and Embryology, Victor Babes University of Medicine and Pharmacy, Timiºoara, for over 50 years. The making of corrosion concoction followed the recipe of the laboratory using type AGO II plastic substances, differently colored and then subjected to the corrosive action of hydrochloric acid. During the routine check outs all the pregnant woman’s were diagnosed with thrombophilia. The examination of the placental parameters - shape, weight, thickness - is important as a preliminary stage for the study of the placental architecture. The normal placental development remains a major factor in the growth and development of the fetus, and the maternal-fetal placental vasculature is essential in this regard. Placental angiogenesis has a different local component of angiogenesis, found in other anatomical regions.
682 – 688
Parametric Study of Experimental and Numerical Simulation of Sandwich Composite Structures Flexural Behaviour
Elena Felicia BEZNEA, Ionel CHIRICA, Nicusor BAROIU, Virgil TEODOR
Open Access DOI: 10.37358/MP.17.4.4925
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Abstract: Sandwich panels with composite/steel skin sheets and foam core are very often used as lightweight structures in automotive, maritime and aerospace applications due to their performances like high bending stiffness and strength and also lightweight. As an alternative to classical structural reinforced panels, the sandwich structures are justifying their use in various industrial fields, making these structures less complex, by eliminating the need for secondary stiffening. In the paper are presented three models of sandwich, steel-foam-steel, composite-foam-composite or steel-foam-composite structures, of different thicknesses, with functional use in various fields depending on necessities. The mechanical characteristics of the materials used in their manufacture have been determined. The panels have been subjected to various load cases in order to determine an optimal combination of weight and strength. At the same time, the numerical models used in the finite element analysis of the sandwich structures with specific elements for layered composites or sandwich (SHELL 4L and SOLID L) are presented.
689 – 693
Study Regarding the Surface State of Composite Resins After Finishing and Polishing Using Different Systems
SORIN ANDRIAN, GIANINA IOVAN, GALINA PANCU, CLAUDIU TOPOLICEANU, ANDREI GEORGESCU, SIMONA STOLERIU, et al.
Open Access DOI: 10.37358/MP.17.4.4926
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Abstract: The aim of this study was to evaluate the influence of different finishing and polishing systems and of composite resins structure on surface state of the restoration. Cylindrical samples from two different composite resins (Filtek Z 550 and Filtek Z 250, 3M ESPE) were obtained. In group 1 the samples were not finished and polished. In groups 2-4 the samples were submitted to finishing procedure using two tungsten carbide burs, then polished using three different polishing systems: three steps diamond abrasive polishers (Kenda CGI, Lichtenstein) - group 2, one step silicon carbide abrasive particles brush (Occlubrush, KerrHawe SA, Switzerland) - group 3 and two steps Sof-Lex spiral wheels (3M ESPE) - group 4. Half of the samples in each group were subjected to surface microstructure evaluation using a scanning electron mycroscope. The other half of the samples was subjected to surface state assessment using profilometery. All the investigated finishing and polishing systems leaded to increased surface roughness when compared to the roughness of composite resins placed in direct contact to celluloid clear matrix. The surface roughness of both microfilled-hybrid and nanofilled-hybrid composite resins finished and polished with different systems were influenced mostly by the polishing system and less by the composite resin structure.
694 – 699
Fatigue Crack Propagation and Charpy Impact Properties in Armor Steel Welds
Aleksandar Cabrilo, Miroslav Cvetinov
Open Access DOI: 10.37358/MP.17.4.4927
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Abstract: The process of welding armor steel is a complex process because of possible welding faults, appearing in the weld metal zone in the form of cracks and pores. Austenitic filler material is traditionally used for welding armor steels. For heavy structural engineering such as armored military vehicles, which are frequently under the effect of dynamic load, it is important to know the dynamic properties of the most sensitive area of welded joints, the weld metal zone. Due to a significant interest in quantification of material resistance to crack initiation and propagation, the fatigue crack growth rate was measured in the welded metal zone, while the resistance to crack growth in the weld metal was tested by the amount of austenite transformed into martensite. Accordingly, the threshold stress concentration factor was 10 MPa m1/2. XRD spectral analysis revealed direct transformation of g - austenite into a’ -martensite.
700 – 707
Impact Testing on Composite Panels of Fiberglass, Carbon and Kevlar-Carbon A comparison and validation study
EMILIAN IONUT CROITORU, GHEORGHE OANCEA, NICOLAE CONSTANTIN
Open Access DOI: 10.37358/MP.17.4.4928
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Abstract: A validation study between finite element analysis and experimental testing considering an impact loading of Fiberglass, Carbon and Kevlar-Carbon composite panels of 150 x 100 mm2 was conducted by the authors. Using the design of experiments method and the Design Expert software tool, the data obtained in FEA environment is validated, through means of statistical distributions, by the experimental tests results.
708 – 714
Effects of (complementary) Polyelectrolytes Characteristics on Composite Calcium Carbonate Microparticles Properties
Cristian Barbu Mic, Marcela Mihai, Cristian Dragos Varganici, Simona Schwarz, Dan Scutaru, Bogdan C. Simionescu
Open Access DOI: 10.37358/MP.17.4.4929
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Abstract: This study follows the possibility to tune the thermal stability of some CaCO3/polymer composites by crystal growth from supersaturated solutions controlled by polymer structure or by using nonstoichiometric polyelectrolyte complexes (NPECs). As the ratio between the organic and inorganic parts in the composites controls the Ca2+/polymer network crosslinking density, the CaCO3/polymer weight ratio was kept constant at 50/1, varying the initial concentration of the polyanions solutions (0.05 or 0.06 wt.%), the NPECs molar ratio , n+/n- (0.2 or 0.4), or the inorganic precursors concentration (0.25 or 0.3 M). Poly(2-acrylamido-2-methylpropanesulfonic acid-co-acrylic acid) (PSA) and chondroitin-4-sulfate (CSA) were used as polyanions. Some NPEC dispersions, prepared with the same polyanions and poly(allylamine hydrochloride) (PAH), were also used for calcium carbonate crystallization. The characteristics of the prepared composites were investigated by scanning electron microscopy (SEM), flow particle image analysis (FPIA), particles charge density (CD), zeta-potential (ZP). The thermal stability of the composite particles was investigated as compared to bare CaCO3 microparticles prepared at the same initial inorganic concentrations.
715 – 719
Structural Analysis of Fragments of the Broken Coat of a Cylinder which Led to the Dismantling of a Combustion Engine
FLORENTINA POTECASU, MARIAN BORDEI, ION SANDU
Open Access DOI: 10.37358/MP.17.4.4930
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Abstract: The paper presents the structural analysis of cast iron fragments from the cylinder coat of a combustion engine, as a result of the broken down through explosion. Initially, determinations of the chemical composition were made and it was found that although the cast iron had the carbon content imposed. As a result, detailed microstructural analyzes were made regarding the shape, size and distribution of graphite in the cast iron as well as for the identification of structural constituents and constitutive phases. The same investigations were carried out on samples taken from a cylinder coat with a good functioning for comparison (blank samples). The metallographic study revealed characteristics of inappropriate graphite separations (graphite type B, D, E) and areas with specific structural constituents to the mottled cast iron that can cause breakage of the cylinder coat and excessive wear of the segments.
720 – 725
Comparative Studies on the UV Radiations Resistance of Some Painting Materials
Traian RUS, Iosif LINGVAY, Alina Ruxana CARAMITU, Adriana Mariana BORS, Danut Ionel VAIREANU
Open Access DOI: 10.37358/MP.17.4.4931
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Abstract: UV radiation has a long-term effect on the durability of anti-corrosive coatings applied by painting, generating conditions for accelerated localized corrosion of the protected metallic structure with adverse effects on operational safety. This paper presents a comparative study of the behavior of some painting materials ageing by exposure to UV radiation relevant by the investigation of dielectric behavior using dielectric spectroscopy in conjunction with the thermal stability investigated by coupled techniques of thermal analysis. From a practical point of view, the UV radiation behavior of two materials based on epoxy resins and polyurethane resin used as paints for protective decorative coatings was studied. The results of experimental investigations have shown that in the aging process of the studied painting materials there is a direct correlation between the evolution of the maximum temperature characteristic of the first thermooxidation process and the evolution of the dielectric performances (dielectric loss – tgd).
726 – 730
Ultrafiltration of Aqueous Solutions of Food Dye Using Polymeric Membranes Prepared with Surfactants
George Alexandru Popa, Daniela Florentina Enache (Popa), Szidonia Katalin Tanczos, Adrian Ciocanea
Open Access DOI: 10.37358/MP.17.4.4932
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Abstract: The objective of the study is the low-pressure membrane process for treating aqueous solutions containing synthetic food dye (E104 – quinoline yellow). Dye concentration used was 10% (equivalent to 100g/m3). The pressures used in the ultrafiltration process were 0.1, 0.2 and 0.3 MPa. Experiments were performed in dead - end instalations in which the effectiveness of the polysulfone - alkylbenzyldimethylammonium chloride (PSU-ABDMA) and polysulfone - N-dodecylpyridinium chloride (PSU - NDPCl) were tested. The efficiency of these membranes has been proved by calculating the permeate flow and the retention. Analyzing the experimental data, it was found that for the polysulfone-alkylbenzyldimethylammonium chloride composite membrane the degree of retention is completely different, with high values being obtained for low pressures and low values for high pressures used.
731 – 734
Treatment Planning Optimization in Radiotherapy Using the Bolus
ANCA MUNTEANU, FLORINA DANIELA IVAN, ALEXANDRU PATRASCU, VERA BALAN, CATALINA URSACHE, LILIANA VERESTIUC
Open Access DOI: 10.37358/MP.17.4.4933
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Abstract: The present paper presents the results of the research regarding the bolus structure (Bio-Rad Win-IR instrument), the elasticity modulus, the bioadhesiveness properties (TA-XT2 Plus analyzer) and the clinical applications of the bolus in the adjuvant irradiation after radical mastectomy (Treatment Plan System Eclipse). The dose-volume histogram has made a comparative evaluation for with and without bolus treatment plans and confirmed the importance of bolus utilisation in selected patients. Conclusions: the thickness of the applied bolus is dependent on the skin dose required, on the treatment technique and must be equal to the depth of the build-up region for the removal of the skin-sparing effect of a high energy radiation.
735 – 739
Morphology and Rheology of Nanofilled PP / PVA Blends
NATALIA REZANOVA, YURII BUDASH, VIKTORIIA PLAVAN, OLENA IShchenko, VIKTORIIA BULAKH
Open Access DOI: 10.37358/MP.17.4.4934
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Abstract: The influence of Ag/SiO2 as nanofiller and sodium oleate as compatibilizer and their mixtures on the patterns flow and structure formation processes in thermodynamically incompatible polypropylene/plasticized polyvinylalcohol (PP / PVA) systems were studied. It is found that the change in the sequence of mixing the ingredients of the composition allows adjusting the morphology phase type due to the predominant localization of nanoparticle additives in the melt amount of a component or on the border of phase separation. Injection of Ag/SiO2 to melt PP increases dispersion degree and homogeneity of its distribution in the matrix. Simultaneous use of nanoadditive and sodium oleate as compatibilizer improves the connections between the polymers and promotes thinner and more homogeneous dispersion of the particles of the dispersed phase. It is shown that the effective viscosity of melt nanofilled system is determined by components mixing method: viscosity of melt blend increases when the additive is localized predominantly in the PVA and decreases with the prior injection of PP. The nature of the flow for all researched compositions obeys a power law and almost does not depend on the method of mixing. The ability of the longitudinal deformation of ternary blends is deteriorating, but remains sufficient for their processing. Combining nanoadditive with compatibilizer promotes increased elasticity and the melt spinnability of modified blends.
740 – 747
Study of Marginal Microleakage in Root Caries Restored with Resin Composites, Giomers and Glass Ionomer Cements
DAWOD NAZEM, CORNELIA FLORENTINA BICLESANU, DOINA PALUTA, STEFAN MANEA, MONICA BANITA, VIOLETA HANCU, et al.
Open Access DOI: 10.37358/MP.17.4.4935
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Abstract: Root decay is a complex and multifactorial disease. The aim of this study is to assess in vitro the sealing capacity of common aesthetic materials used to restore root caries as well as the size of the hybrid layer formed by SE-1 step vs 2-step ER adhesive techniques. For this study, 45 extracted teeth were used. After cleaning, near the enamel-cement junction, but at the level of the cementum, cavities were prepared and restored with resin composite, giomer and glass-ionomer cements. The teeth were covered with nail polish leaving uncovered the restoration area and 2mm around it; teeth were kept for 24 h , in 2% methylene blue. To assess the degree of marginal adaptation, SEM analysis was further performed. The association of 2-step ER adhesive system with giomers and resin composite shows the maximum adhesion efficiency by forming a uniform, thick layer and dentinal tubules obliteration compared to SE-1 step adhesive system associated with the same restoration materials.
748 – 751
A New Colorimetric Assay for Determination of Selected Toxic Vapors and Liquids Permeation Through Barrier Materials Using the Minitest Device
PAVEL OTRISAL, STANISLAV FLORUS, LUBOMIR SVORC, GHITA BARSAN, DANUT MOSTEANU
Open Access DOI: 10.37358/MP.17.4.4936
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Abstract: A moment of permeation of both gaseous and liquid phases of a toxic compound through a barrier material has been indicated colorimetrically at the same time on 20 exposed places using suitable colour indicators. The newly developed device MINITEST is able to evaluate the resistivity of both porous and non-porous barrier materials of a textile character against permeation of toxic vapours (permeation) and liquids (penetration) in static conditions. As a model test chemical either the sulfur mustard or significantly alkaline or acid volatile toxic compound have been applied. During the permeation, these species react with a suitable acid-base indicator and a markedly coloured stain can be created. Newly developed MINITEST device enables determination of chemical resistance of areal barrier materials not only in a process of their development but also in the rate of their practical applications.
752 – 753
Procalcitonina - Diagnostic Marker in Neonatal Sepsis
Amelia Milulescu, Florin Dorneanu, Daniela Iacob, Dana Stoian, Izabella Petre, Veronica Daniela Chiriac, et al.
Open Access DOI: 10.37358/MP.17.4.4937
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Abstract: Procalcitonin was proposed to have been a more specific and better value compared to CRP as a marker of prognosis, although its diagnostic value is also contested.This study was conducted in the Department of Neonatology and the Department of Obstetrics and Gynecology of “Pius Brînzeu” Emergency County Hospital Timisoara on a group of 20 newborns coming from 20 mothers that have been found with low procalcitonin. The gestational age at birth was 36-39 weeks. PCT values do not correlate and do not indicate correctly viral infections. Serum PCT levels must be interpreted within the clinical setting; there are many other causes that could lead to its growth. Our study consists of two different parts. In the first part we computed a regression model in order to see if there is any association between the vales of procalcitonin obtained from the blood analysis of the mother and the procalcitonin of her child.
754 – 756
Polymeric Alternatives in Manufacturing Removable Partial Dentures
LAVINIA COSMINA ARDELEAN, CRISTINA MARIA BORTUN, ANGELA CODRUTA PODARIU, LAURA CRISTINA RUSU
Open Access DOI: 10.37358/MP.17.4.4938
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Abstract: Traditionally, removable partial dentures consist of a metallic framework, covered by acrylic saddles, which support acrylic or ceramic teeth. Because their shortcomings, new classes of resins/macromolecular compounds which promise better quality are nowadays available for manufacturing removable partial dentures: urethane-based resins, polyamides, acetal resins, high-performance polymers. Manufacturing these new materials implies alternative technologies like: injection, milling, light-curing. Using these alternative polymeric materials results in dentures with better resistance, elasticity, appearance and lower weight, which provide much more comfort to the patient.
757 – 758
Custom Designed Orthodontic Attachment Manufactured Using a Biocompatible 3D Printing Material
RIHAM NAGIB, CAMELIA SZUHANEK, BOGDAN MOLDOVEANU, MEDA LAVINIA NEGRUTIU, COSMIN SINESCU, SILVIU BRAD
Open Access DOI: 10.37358/MP.17.4.4939
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Abstract: Treatment of impacted teeth often implies placing a bonded attachment and using orthodontic forces to move the tooth into occlusion. The aim of the paper is to describe a novel methodology of manufacturing orthodontic attachments for impacted teeth using the latest CAD software and 3D printing technology. A biocompatible acrylic based resin was used to print a custom made attachment designed based on the volumetric data aquired through cone bean computer tomography. Custom design of the attachment simplified clinical insertion and treatment planning and 3D printing made its manufacturing easier. Being a first trial, more reasearch is needed to improve the methodology and materials used.
759 – 761
Evolution of the Plasticity of Some Low Carbon Steels, Subjected to Directed Cooling from High-temperature
CARMEN PENELOPI PAPADATU, IOAN GABRIEL SANDU, MARIAN BORDEI, ANDREI VICTOR SANDU
Open Access DOI: 10.37358/MP.17.4.4940
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Abstract: An important influence factor for the plasticity of the low carbon steels is the cooling speed value after heating treatment. It is important to be chooses the optimal cooling regime for these materials because the steels have been laminated at high temperature or, the steels have been heated at high temperature after lamination process. There were considered two groups of samples of two low carbon steels, each group had eight samples. Three different mediums for directing of the cooling process were considered and the properties of the steels have been modified. After an experimental program, the values obtained were used to determine the variation between these variables corresponding to two kinds of steels (coded: Steel 1 and Steel 2).
762 – 767
Trinia Reinforced Polymer as Core for Implants Superstructure
CARMEN BIRIS, EDWIN SEVER BECHIR, ANAMARIA BECHIR, FARAH CURT MOLA, AURELIANA CARAIANE, ADRIAN VIOREL BADIU, et al.
Open Access DOI: 10.37358/MP.17.4.4941
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Abstract: The intraosseous implants are the most used dental implants. The development of new classes of dental biomaterials determined the apparition of Trinia, a Computer-Aided Design/Computer-Aided Manufacturing (CAD/CAM) reinforced polymer, used for core in non-metallic prosthetic restorations, including implants superstructure. The aim of the study was to present the obtained results in the use of Trinia polymer as non-metallic core on the abutments of Bicon implants. 35 patients were selected, 19 females and 16 males, aged between 31 and 60 years. After 18 months of results monitoring, we ascertained that Trinia reinforced polymer had a very good behavior in the oral cavity, and the patients did not complain about inconveniences due to the oral rehabilitation with this biopolymer.
768 – 772
Experimental Characterisation of Hyperelastic Materials for Use in a Passive-Adaptive Membrane on MAVs Wing
RADU CALIN PAHONIE, CIPRIAN LARCO, MIHAI MIHAILA ANDRES, VASILE NASTASESCU, CRISTIAN BARBU, CARMEN LUIZA COSTULEANU
Open Access DOI: 10.37358/MP.17.4.4942
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Abstract: The paper focuses on the experimental characterization of hyperelastic of the shelf materials in an effort to implement a membrane skin on a low speed asymmetric wing, in order to assess the benefits of flexible lift surfaces. To better determine the best strain energy function definition for the membrane materials, the most notable hyperelastic constitutive models were used together with experimental uniaxial and equiaxial planar tests. For the experimental equi-biaxial test a special loading device was designed and built in the laboratory. The strain measurements for the experimental tests were conducted using digital image correlation, for increased data precision. From the available constitutive material models taken into account, the best for this application proves to be the Yeoh model, as the experimental strain-stress data has a close match for small as well as large strain values. Numerical simulations using finite elements and the Ansys software were performed to predict the materials behavior.
773 – 776
Biomaterials used in Reduction and Fixation of Unstable Fractures of the Zygomaticomaxillary Complex
Cristian Budacu, Alexandru Nemtoi, Mihai Constantin, MARIUS CRISTIAN MARTU, Danisia Haba
Open Access DOI: 10.37358/MP.17.4.4943
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Abstract: This study evaluated a series of cases of fracture in the zygomaticomaxillary complex with displacement of the fractured segment which were evaluated before and after treatment with cone beam CT. The treatment perfomed was represented by titanium micro-plates and screws. The study sample which consist of 25 patients of both genders with fractures in the zygomaticomaxillary bones. After clinical examination to arrive at correct diagnosis and treatment plan, each patient was subjected to 2D and 3D reconstruction using cone beam CT. Reffering to the type of treatment was evaluated the procces of bone remodelling and also the osseointegration process of the titanium micro-plates and screws used for reduction and fixation of the fractures. The treatment performed for all patients was reduction and fixation with titanium micro-plates which were osseointegrated partially in 45 % of patients and 3 screws were not osseointegrated.
777 – 780
Analytical Methods and Finite Element Method Computation The dental - periodontal tissues response
CRISTINA BICA, KRISZTINA MARTHA, DORIN BICA, DANIELA ESIANU, MADALINA NICOLETA MATEI
Open Access DOI: 10.37358/MP.17.4.4944
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Abstract: The study of the biomechanical behaviour of dental-periodontal structures during orthodontic movement has been carried out on the basis of the analysis of values of equivalent stress following Von Mises theory, of the stress after the direction of the sz vertical force, which constitutes the essential component of the Von Mises equivalent stress, as well as on the basis of registering the deformities on the tooth axis. The processes of implementation, modelling, calculation and interpretation, using FEM, involved the following steps: defining the geometry and the structure of the model under analysis; meshing the geometry of the structure; connecting the nodal elements; defining the limit conditions and restrictions; loading the created model with vertical forces of different intensities; solving the equation system, having as unknowns in the nodes the following: movement, tension, tension on the spatial coordinates, Von Mises stress. We simulated the orthodontic intrusion through the application of some vertical forces with different intensities and on structures with alveolar bone loss. The tension values in the tooth axis vary in direct proportion to the level of resorption of the alveolar bone, but the decisive element is the numerical value of the applied force, and not the absorption level.
781 – 784
Monitoring of Mercury Content in the Main Environmental Components Caused by Lignite Combustion in Large Thermal Power Plants
DELIA NICA BADEA, MIHAELA GABRIELA DUMITRU, IGOR CRETESCU
Open Access DOI: 10.37358/MP.17.4.4945
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Abstract: The aim of experiment was to evaluate the local impact of mercury accumulations, discharge from coal power plants, by examining samples of ash, slag, soil, spontaneous vegetation and crop plants, using as analytical techniques the cold vapor atomic absorption spectroscopy. Mercury determined in samples of lignite (0.020 mg. Kg-1), is found in fly ash samples retained by filters (0.037 mg.Kg-1), bottom ash transported hydraulic in deposit (0.022 mg.Kg-1), adjacent soils landfill and the power plant (0.12 mg.Kg-1 or 0.049 mg.Kg-1). The mercury content in vegetation presents differentiated values depending on the bioavailability of plant, area and the positioning of the emission source, reaching values between 0.014 at 0.005 mg.Kg-1 in the wild flora and 0.022 mg.Kg-1 to 0.004 mg.Kg-1 for plants crop. Data obtained for plants, confirmed that most families tend to accumulate mercury plant in larger quantities in the roots (0.022 ± 0.0016 mg.Kg-1) and moderate quantities in the foliar level by translocation or by direct vapor absorption.
785 – 787
Chylothorax Consecutive Heartworm Disease in Dog
ADRIAN STANCU, ALINA GHISE, MARIUS PENTEA, DELIA MIRA BERCEANU VADUVA, DANA EMILIA VELIMIROVICI, LILIANA CARPINISAN, et al.
Open Access DOI: 10.37358/MP.17.4.4946
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Abstract: Chylothorax was diagnosed in a Afghan dog 3 year old, that presented in the necropsy a accumulation of lymphatic fluid in the chest cavity. Also to examine the right heart was observed to this heartworms – Dirophylaria immitis.
788 – 794
Cochlear Implant Strategies and Biomaterials from Past to Future
Marius Cristian Martu, Sebastian Cozma, Vasile Dan MARTU, Roxana Serban, Dragos Bularda, Corina Butnaru, et al.
Open Access DOI: 10.37358/MP.17.4.4947
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Abstract: The cochlear implant (C.I.) is a neurobionic prosthesis, being one of the greatest achievements of auditory neuroscience. Although C.I. represents the gold standard in the treatment of deafness in both the child and the adult, some problems like perception of speech in noise (atmosphere, environment), perception of music, binaural hearing remain, aspect to which improvements are expected. The article (this review) revises the road from the first attempts to cochlear implantation to today’s modern and reliable cochlear implant. Continuous improvement of existing technology both in terms of biomaterials used and in terms of speech processing and simultaneous stimulation strategies, promise with certainty the introduction of C.I. with superior performance. A look in the future is through new ideas and techniques, which await the transition from the experimental to the clinical stage in the emergence of a new generation of implants.
795 – 799
Clinical Outcomes in Implant-Supported Full-Arch Fixed Prosthesis Utilizing Pressed Composite Restorations
Sorin Gheorghe Mihali, Emanuel Adrian Bratu
Open Access DOI: 10.37358/MP.17.4.4948
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Abstract: The author wants to evaluate the clinical advantages and limitations of the composite pressed on metal framework for full-arch implant-supported fixed prosthesis in comparing with dental ceramic restorations. A total of thirty-two edentulous arches were restored. All complications were recorded at each follow-up visit up to 1 year after insertion. No complications were reported on pressed composite restoration. Complications were found in the ceramic restorations like chipping or fracture of the ceramic veneer. The composite pressed restorations are a treatment option for full arch restorations over implants, showing a better success rate in the present study in comparing with ceramic restorations.
800 – 805
ASSESSMENT OF PHYSICAL PROPERTIES OF STRUCTURED OILS AND PALM FAT
Sylwia Onacik Gur, Anna Zbikowska, Marzena Przybysz, Malgorzata Kowalska
Open Access DOI: 10.37358/MP.17.4.4949
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Abstract: Oleogels are structured liquid oils with applications in food, cosmetic, and pharmaceutical industries. Structured oils may become alternatives to the commonly used solid fats, such as palm fat or hydrogenated fats. Properties of oleogels are primarily dependent on the structuring agent applied. This paper was intended as an examination of structuring properties and oleogel oil binding capacities of various monomer ingredients (plant and beeswaxes, monoacylglycerol) and comparison of the oleogels produced with palm fat. An oleogel produced with candelilla wax (CLX) exhibited a structure most similar to that of palm fat. These products showed statistically significant differences of colour from palm fat. In addition, textures of the oleogels differed from one another and from palm fat. Oleogel containing rice bran wax (RBX) had the most similar viscosity properties. Oleogels including candelilla wax and yellow bees wax displayed best oil binding structures (assayed by centrifugal and LumiSizer methods). When filtered (at 40°C), on the other hand, minimum oil loss after 24h was demonstrated by the oleogels containing CLX and RBX, possible evidence that these structure-forming substances roduce oleogels that could be used in products exposed to more elevated temperatures. Oleogels may become alternatives to the commonly used solid fats. Thanks to the use of oil structuring agent at the level of 3% liquid oil becomes solid. Using these innovative fat products can stabilize oil in the product, and also it can improve the nutritional value of food products by replacing a popular palm fat rich in saturated fatty acids, which exert an adverse influence on humans’ cardiovascular system, by oils rich in unsaturated fatty acids.