Volume 56, Issue 1

Abstract: In this paper, we examine two types of Dammar-based bio resins. In the first type, Dammar alone is used as natural resin, while in the second type a mixture of 70% Dammar and 30% Sandarac is used. Three sample sets were made of each of these resins with a bio resin volume proportion of 55, 65 and 75% respectively, the rest being epoxy resin (used, together with the associated reinforcing material, to generate a quick polymerization process). A SEM analysis is carried out and the surface roughness of each of the studied materials. A series of mechanical properties, determined by tensile testing, are presented. We have determined the characteristic curves, tensile strength and modulus of elasticity and the influence of the epoxy resin volume proportion on the mechanical behaviour of bio resins.

Abstract: In this paper, the authors show a part of research works performed on the use of 3D scanners and 3D printers to execute the molds required for the cast of parts with complex surfaces. 3D scanning allows copying of certain surfaces in our environment, based on existing models. The finished parts may also be executed from metals that are relatively easy to cast (bronze, aluminum etc.). In order to execute the molds destined for the casting, various pieces may be scanned, with a volume size in the range of [150x150x200 mm3 ÷ 500x500x2000 mm3]. Plastic model printing is performed depending on the capacity of the 3D printer used. This paper shows the results achieved with general-purpose scanner and printer, valued at affordable prices.

Abstract: The body of a craft is subjected to a series of complex loads, both static and dynamic. The global strength of such a body is given by the entire assembly of the hull, deck and strengthening framing system, all of these components working together [1]. Such a boat must first of all fulfill a very important requirement, namely: minimum hull resistance so that the engine power would primarily be used to achieve the highest possible speed. This can only be achieved if the hull wetted surface is as small as possible, which leads to the need to reduce the hull asembly weight. Thus, in this paper there are proposed and tested a number of nine lamination alternatives for the initial structure, designed as a sandwich system with different types of core materials. From the total nine alternatives, three of them are hybrid structures in which there are explored structural alternatives with several types of core materials. The verification of structures obtained with the proposed materials and lamination schedules was made using numerical methods both for naval hydrodynamics to determine loads and for naval structures for global body strength and analysis.

Abstract: The main target of the study is to highlight, by means of numerical simulations, the advantages and possible drawbacks of using composite materials instead of the classical cast iron to equip the brake system of railway freight vehicles. The qualitative and quantitative evaluations refer mainly to the braking capacity by considering as main parameter the stopping distance, in various operational conditions. Results indicate that composite materials are more efficient in the braking process, but in the case of low speeds, the recommendation is to perform earlier and/or stronger braking actions than usual, in classical cast iron equipment on rolling stock.

Abstract: This paper presents a study based on simulating the impact between a yarn (or a single fiber with greater dimensions) and a bullet, the impact velocity being 400 m/s. The characteristics of the involved materials are taken from literature. The yarn is considered isotrope, but the values of the characteristics are close to those of aramid fibers and cooper and lead alloys used for manufacturing the bullets. Analysing the yarn failure caused by a bullet, this FE model allows for identfying the stages in the failure process. First, the yarn is pushed by the bullet and the local elongation of the yarn is tacking place. The yarn rupture occurs in the “strangled” zones, caused by the stretch of the yarn directly supporting the impact. The breaking of the yarn in the thinned zone (more pronounced asymmetric breaking) and it is visible that the yarn elastic recoil starts next the bullet. The friction between the yarn and the bullet is only on the conical surface of the bullet in the tapered zone of the bullet. The yarn is detaching from the bullet (the contact zones between the bullet and the yarn in polymeric matrix become smaller, justifying a neglectable influence of the thermal effect). The yarn has no more contact with the bullet. This step is in the favor of the assumption that, in the actual multi-yarn impact, the other layers of yarns maintain the bullet and the first yarns in contact and this is why bunch of fibers (fragments of the failed yarns) are pressed against the bullet and remain on it. The simulation results were qualitatively validated by SEM investigations of fiber failure under the same conditions as the model.

Abstract: Environmental problems occurring in isolated or hardly accessible inhabited areas can be adequately addressed using membranes and membrane processes.In the present paper, the recuperative separation of aluminum ion from the aluminum sulfate-treated water through permeation using capillary composite membranes, from polypropylene with ethylene propylene diene terpolymer sulfonic acid (PP / S-EPDM) inclusions is followed by the reaction of complexation with 8-hydroxy quinoline. The installation used for studying the permeation process provides a usable surface area of 1 m2, the source phase solution volume is 3 L, and the receiving phase is 300 mL. The two phases are recirculated through the outside of the membranes (SP) and respectively through membranes (RP), by means of individual peristaltic pump that can provide flow variations between 2 and 200 mL / min by varying the intensity of the power supply. The optimal operating parameters were determined: operating time, pH and receiving phase flow, thus achieving an ionic flux (IR) above 10-11 mol / cm 2. s and a recovery factor (RF) over 90%.

Abstract: Percutaneous coronary revascularization (PCR) with polymer-coated drug-eluting stents (DES) or bare-metal stents (BMS) is considered the standard therapy in advanced ischemic heart disease (IHD). Despite revascularisation, many of these patients subsequently develop heart failure with reduced ejection fraction (HFrEF). We analysed 51 patients with IHD, treated by PCR and insertion of DES and/or BMS who later developed HFrEF. Patients with DES where more likely women, of younger age and a higher incidence of diabetes mellitus compared to patients with BMS who were generally men, of older age and had more frequently acute ST-elevation myocardial infarction (STEMI) as indication for PCR. Although patients with DES had more severe IHD, their EF was higher, possibly due to the benefits offered by the DES.

Abstract: The pyrolysis can be an attractive way to reduce the plastic waste and, in the same time, to obtain alternative conventional fuels. In this respect, four polymers (low-density polyethylene, high-density polyethylene, propylene and polystyrene) were used in the pyrolysis process. The experiments were carried out by using an in-house plant, which allowed a maximum test temperature of 450 °C. The product oil and the derived gas from the pyrolysis process were evaluated using different techniques, such as elemental analysis (EA), calorimetry, gas chromatography (GC), gas chromatography coupled with mass spectrometry (GC-MS). Furthermore, for a comparative study two catalysts, zeolite and lignite, were also used for the pyrolysis process, in order to observe their influences on the final products. The higher heating value obtained for the oil was in the 40.17-45.35 MJ/kg range, acceptable for the use of these oil as an alternative fuel for diesel engine. Also, the sulphur content from the obtained oil does not cause environment problems, being lower than the allowed limits (10 mg/L). In addition, the pyrolysis derived gas was rich in hydrocarbons, conducting to a high calorific value, in the 73.42 – 121.18 MJ/kg range.

Abstract: Some disadvantages of traditional metallic implants used in orthopedics and traumatology prompted the development of bioresorbable polymer devices.The aim of this experimental study is to emphasize the characteristics of INION® resorbable implants (regarding design and polymers compositions), as well as to evaluate the results when using these innovative implants in two trauma cases. The polymers used in manufacturing INION® devices (Trimethylene Carbonate/TMC; L-Polylactic acid/LPLA; D,L Polylactic acid/DLPLA; Polyglycolic acid/PGA) degrade in alpha-hydroxy acids, gradually losing their hardness in 18-36 weeks with a complete bioresorption of 2-4 years. The clinical cases demonstrated the advantages of INION® plates (adapted shape, low profile, polyaxial screws, acceptable strength) or pins (allowing the aligmment and fixation of fracture, no migration). Among our patients, we found excellent results concerning the maintaining of primary reduced fracture, active range of motion, minimal pain with improving everyday comfort, no tissue or implant complications. Bioresorbable fracture fixation INION® devices are a viable alternative to traditional metallic implants, offering same significant advantages over them: the avoidance of long-term interference with gliding structures, keeping their strength long enough to support bone healing, no need to remove the implants, less pain, radiolucency, elimination of stress shielding and a lower risk of complications.

Abstract: The aim of this study is to compare two different methods used for obtaining printed dental models -intraoral scanning and extraoral scanning; the comparative analysis was made in correlation to the accuracy of the traditional plaster cast model. Nine dental models were obtained: three plaster cast ones, three printed after intraoral scanning and there printed after impression scanning. A total of 137 measurements (arch and tooth measurements) were done on the three types of models and a statistical evaluation was performed (t-test, Fisher Test). Our results highlighted that 3D printed dental models represent a reliable option for clinical application.

Abstract: The application of plastic materials in various areas of contemporary technology can lead to improvements in the function, quality and performance of engineering components. When determining the field of use of these materials, it is necessary, in addition to knowing the physical and mechanical properties, information about their behavior in service under the influence of the operating and environment factors. Compared to metallic or ceramic materials, polymeric materials exhibit a wide range of scratching deformations in a narrow range of pressure, speed, temperature, lubrication etc.In this paper is proposed a penetration model of a flat surface (from polymeric material) with a rigid conical penetrator and the determination of the flat surface material response mode. The penetration method corresponds to the deformation produced by the asperities in practice.The comparison of the experimental and the theoretical results confirms the veracity of the model and corresponds with many of the experimental results obtained in the specialized works.Based on the proposed models, maps can be produced, that can illustrate the response of any polymeric surface in contact with an abrasive material.

Abstract: Reduced graphene oxide (r-GO) was synthesized chemically and it was characterized using Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM) and X-Ray Diffraction (XRD). The results revealed that the product r-GO is nano-sheets with non-smooth surface; the size of the obtained nano-sheets ranged from 20 to 100 nm. The well characterized nano-sheets were subjected to cytotoxicity test; results demonstrated that the nano-sheets show low cytotoxicity on the human cell line compared with the chemical nematicide. The r-GO was tested against the nematode during their life span and it was observed that the r-GO is capable to reduce the nematode gall number and egg mass of 94% and 99%, respectively. Moreover, the toxicity of the r-GO against the Juvenile (J2) root-knot nematode (Meloidogyne incognita) was also examined either in laboratory or under the greenhouse conditions. On the other hand, the treatment with the r-GO under greenhouse conditions showed higher mortality of the J2 of 98.5% compared with nematicidal treatment of 96% in a soil infested with M. incognita. Also, the same treatment was sufficient in inducting the growth of tomato plants: fresh weight of the shoot system increased with 30% and of the root system increased up to 285%; dry weight of the shoot system increased with 128% and of the root system increased up to 480%. r-GO has a high nematicidal activity and it is safe for human. The r-Go could be used as safe nematocide because it is safe, cheep, could be produced at large scale, and it is a good additive for the soil.

Abstract: This paper analyzes the indentation hardness and the indentation elastic modulus variation depending on the variation of the grind percentage of polymer, when the other factors that can influence the injection molding remain unchanged. The analyzed polymers were: acrylonitrile butadiene styrene ABS MAGNUM 3453, polyamide PA 6.6 TECHNYL AR218V30 Blak and polyoxymethylene POM EUROTAL C9 NAT. The samples that were studied had different compositions in new and grinding material. The G-Series Basic Hardness Modulus at a Depth method was used. The increase of the grind percentage of ABS (from 0 to 100 %) leads to insignificant changes in the indentation hardness, indentation modulus, and maximum force applied to samples of tested material. The maximum hardness (0.137 GPa) of PA 6.6 is recorded in the case of the sample with 80% grind content, and the maximum hardness of POM is recorded as well in the case of the sample with 80% grind content, as being 0.215 GPa. The variation of the grind content in the analyzed samples determines changes in the evaluated parameters, depending on the type of polymer. Combining the new material with grind in proportions experimentally established for each techno polymer leads to changes in their mechanical properties.

Abstract: Breast implants are nowadays used in breast augmentation and reconstruction. These can have a silicone or saline filling and a textured or smooth surface. Textured implants have been more frequently used due to their capacity of impairing moving and developing capsular contracture. Breast associated anaplastic large cell lymphoma has been correlated with the presence of textured implants even if the pathogenesis is not entirely understood and other factors might be involved.

Abstract: Plasticity of the steel -as an important property of the material -has the role to show the capability of the steel to support plastic deformation necessary to obtain pieces for industry. Plasticity can be influenced by cooling regimes from higher temperatures in the cases of non-conventional treatments. An important factor is the cooling speed of the steel from higher temperatures during non-conventional treatment applied after lamination of the material. To modify the speed of the cooling, the medium of the cooling has been changed. The samples of the steel have been cooled in normal condition, in metallic box and using a jet of cold air. The evolution of the plasticity was studied taking in consideration the evolution of some characteristics. This paper might be considered as a review of the researches from the last years.

Abstract: Waste electrical and electronic equipment (WEEE) generated in large amounts due to the development of IT and telecommunication industry is considered an important concern for environmental protection. The complex polymer composition of WEEE can be determined in order to consider a proper recycling process for polymeric materials. The aim of the study was to identify the constituent polymers by: density, burning test, solubility, Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC), thermo-gravimetric analysis (ATG). The research led to a majority of polystyrenic polymers, together with polyesters, polycarbonates and polyamides.

Abstract: This study compares the values of the electromagnetic fields generated by three types of microwave ovens with the values available in scientific literature, guides and protocols, considering their impact on human health. Variations in electromagnetic radiation have been determined during and outside the operating time of the microwave ovens at different distances from the oven and in different positions, thereof. The obtained data show higher values of the radiation leakage during operation than those provided by the regulations in force, for all types of studied ovens. The results of the study suggest the need to reduce the time spent near these devices and to optimize the equipment in order to reduce these radiation leakages.

Abstract: In order to identify the causes that led to microbiological degradation by biofouling increases a top coat painting layer applied to a railway bridge was analyzed by both FTIR and the DSC methods; the analysed painting material was that used to paint the bridge in 2013.The determinations were performed comparatively on samples of a similar painting material after 10 days of curing in a natural atmosphere at 25 ± 5 °C, after 60 days of storage under laboratory conditions (22 ± 5 °C, RH 60 ± 10 %, natural lighting), and on samples from the painting material of a certain railway bridge after approx. 4.5 years (exposed natural weathering of temperate climate with Mediterranean influences). From FTIR determinations, the amount of oxygen containing groups (C = O, C-O, C-O-C, -HO) resulted from ageing under various conditions of the painting material.From DSC determinations, the resistance of the paint to the oxidative degradation decreases with the ageing time as resulted from oxidation onset temperatures and oxidation activation energies values – which decreases with 4 kJ / mole (about 2.2 %) in only 60 days of storage in the laboratory and with 7 kJ/mole (about 3.9 %) following exposure to 100 w/m2 for only 15 h and 29 kJ / mole (over 16 %) after exposure to 4.5 years of natural weathering.

Abstract: The photochemical degradation of polyolefin-TiO2 composite films was investigated and described in relationship with the concentration of photocatalyst and after different exposure times. UV-Vis-NIR and IR spectra reveal the presence of various degradation products, which are in direct connection with the photodecomposition mechanism. Various ratios between the absorbance of some typical IR characteristic bands can lead to the evaluation of photocomposition of polyethylene and polypropylene composite films containing TiO2 nanoparticles.The results show that the photocatalytic degradation of composites is significantly faster than the simple photolytic decomposition of pure polypropylene and polyethylene and could be used as a solution for the destruction of this type of wastes.

Abstract: In the field of purification and treatment of waste water resulting from various domestic and industrial activities, classical methods of retention of pollutants almost can no longer eliminate their large quantities, and this signifies a problem related to the environment. Filtration membrane technology has a larger footprint in the removal of these pollutants, and their success is due to virtually the quality of the resulting water. This paper highlights the development of a wastewater ultrafiltration process, containing bentonite, an inorganic compound found in wastewater from industries such as the steel industry, food industry, and so on. This study aims to find the relation between all parameters present in the ultrafiltration process, respectively how these parameters can influence each other. The study is necessary because bentonite, from a common substance, can be a dangerous pollutant, especially if it comes into contact with other compounds that in chemical reactions can harm the environment, and this raises questions to researchers who are experimenting with water purification technologies at a state-of-the-art level. At the same time, the study aims at determining the percentage of bentonite retaining on the membrane filtration surface, and in the final analysis of how bentonite can block the pores of the membrane or deposit on its surface. Throughout the entire ultrafiltration experiment it will be monitorized parameters related to organic membrane with hollow fibers and the results of physico-chemical indicators obtained at the final of the process. The results of the study showed that bentonite can be retained more than 20%. Accumulation of bentonite on the surface of the membrane decreased slightly the volume of permeate at the end of the experiment, resulting in an insignificant decrease in the volume of the liquid in the membrane. The results on bentonite retention efficiency and dependence parameters in the ultrafiltration process will be detailed in the present paper.

Abstract: HDPE composite samples with aluminum and iron nanopowders were made by extrusion and injection. Samples of material obtained were characterized by comparative determinations of dielectric spectroscopy and SEM microscopy. SEM images have indicated that the agglomerations of the powders used are persistent, do not decompose during extrusion and injection processing. Determinations by dielectric spectroscopy indicated that HDPE composite materials with metal nanopowder filler have higher dielectric losses than pure HDPE (reference). The highest increases in tgd up to 2.6 times, were recorded for 50 nm nanopowders with specific high surface area (over 20 m2 / g). The electrical conductivity of the investigated samples increases with increasing frequency, both for pure HDPE and for HDPE with metal powder filler. As a result of the film effect in the HDPE case with metal filler, the increases in the high frequencies range are lower than in the extremely low frequencies range.

Abstract: In this paper, numerical and experimental studies on the influence of the thermal field on behavior of the structure of sandwich plates in three points bending is analysed. Various materials are used so for skins. For the core only extruded polystyrene, with various thicknesses is used. The thermal conductivity n was determined by using the Hilton B480 unit, based on the heat flowmeter method described in ISO 8301:1991. We have been analyzed 12 cases of composite sandwich structures. The results obtained by experimental determination and numerical simulation of all cases of modeling are compared and certain differences occurred on the analyzing of influence of the thermal field on the bending characteristics of sandwich structures.

Abstract: The superior thyroid artery shows a great variability in what concerns its origin. Most often, it appears as an independent branch of the external carotid artery, as its first collateral branch, or directly from the common carotid or at its terminal level. The superior thyroid artery origin was evaluated on 144 cases, using as study methods the dissection (39 cases), the plastic injection (22 cases) and the CT angiography evaluation (83 cases). It was studied, by percentage, the originating artery of the superior thyroid artery, the relation to the bifurcation of the common carotid artery, the neighboring arterial branches and the surface of the external carotid on which originated, the caliber of the external carotid artery before and after the origin of the superior thyroid artery. Most commonly, in 89 cases (61.80%), we describe the origin of the superior thyroid artery from the external carotid artery; from the common carotid artery originated 31 superior thyroid arteries (21.53%); at the level of the bifurcation of the common carotid artery, the superior thyroid artery had its origin in 21 cases (14.58%); in 2 cases (1.39%) we encountered the superior thyroid artery originating from a thyro-lingual trunk and in one case (0.69%), we met a thyro-linguo-facial trunk. The superior thyroid arteries may originate as an independent artery or as arterial trunks in varying proportions. When the origin of the superior thyroid artery is from the terminal common carotid, we propose to use the expression of terminal branching or the common carotid artery trifurcation. The results of our study are similar to those found in international literature, with statistical differences that may be attributed primarily to the total number of cases on which we worked and also working methods or may be attributed to other causes, such as the geographic area where the study was conducted and the amount of time the results were obtained.

Abstract: The aim of this study was to compare the evaluation of two groups of denture wearers following specific parameters at 6 and 12 month after the treatment..The study group included 15 patients with Cr-Co alloy skeletal dentures with metallic crowns with distal occlusal clasps and the base of methyl polymethacrylate (PMMA) and 15 with partially flexible dentures made of super-nylon polyamide resin. Based on the evaluation of these dentures, the 7 clinical parameters stated, over a period of 18 months and within the limits of this study, it can be concluded that partial removable dentures made of nylon-Valplast superpolyamide can be considered as a viable option to Cr-Co alloy.

Abstract: The paper presents the obtaining, characterization and testing of a new type of polyelectrolyte based on acrylamide (2.63 mol/L), acrylic acid (1.73 mol/L) and sodium alginate (4.63x10-3 and 9.26x10-3 mol/L), for flocculation purposes. Two types of monomeric solutions were irradiated in electron beam at room temperature and in atmospheric conditions with doses between 0.5 and 2 kGy using ALID 7 linear electron accelerator of 5.5 MeV. The potassium persulfate (9.25x10-4 mol/L) was used as reaction initiator in both types of solutions. The flocculants thus obtained were characterized using various physical and chemical methods in order to determine conversion coefficient, residual monomer content, intrinsic viscosity, grafting ratio and grafting efficiency. The flocculation efficiency was evaluated in 0.1 and 0.2 wt % blue kaolin suspension at room temperature using a standard Jar test apparatus.

Abstract: In order to evaluate the behavior in various electrical applications, the main mechanical and electrical characteristics of three different varieties of specifically chosen lacquers - based on alkyl-epoxy-melamine copolymer, the epoxy polymer and polyurethane were compared. From the mechanical determinations, it was found that at ambient temperature the polyurethane lacquer bending resistance was approximately equal to that of the epoxy lacquer and about 6.5 times higher that of the alkyl-epoxy-melamine copolymer. It has also been shown that at bending force of less than 150 Nm the investigated polyurethane lacquer has relatively large deformations of 0.4 mm / kN, which indicates a high capacity to take over relatively high deformations of the metal support (due to thermal expansion from various applications) without significant increasing mechanical stress. The recorded values for the alkyl-epoxy-melamine-based copolymer lacquer and the pure epoxy lacquer are 0.11 mm / kN and 0.03 mm / kN respectively. Determinations by dielectric spectroscopy have shown that at frequencies below 250 Hz the dielectric losses tgd for the epoxy and polyurethane lacquers are approximately equal and are about 2.9 times lower than for the alkyl-epoxy-melamine copolymer lacquer. It was also found that at frequencies higher than 250 Hz the investigated materials behave differently, respectively at the frequency increase up to 10 kHz, the dielectric loss tgd of the polyurethane lacquer remains constant at about 0.0045 in contrast to the epoxide lacquer at which the dielectric loss tgd increases monotone to 0.0095 at 10 kHz, respectively of the alkyl-epoxy-melamine copolymer at which the dielectric loss tgd is approximately constant 0.012 in the 250 Hz-10 kHz range.

Abstract: The products used in cosmetic formulations are continuously diversifying as a result of researches in the field, which combine the healing and prevention of many skin conditions with the use of natural products such as vegetable extracts and essential oils. Testing the stability and compatibility of new or modified cosmetics is required to ensure that quality standards are met when stored in proper conditions for functionality and aesthetics, to preserve their chemical, microbiological and physical properties. In this study, the stability and compatibility of a new cosmetic product containing lavender essential oil in plastic container-plastic jar 100 mL PPH Polypropylene homopolymer (Moplen HP648T) is tested against the glass receptacle used as a control. The monitored parameters were organoleptic characteristics (appearance, color, fragrance), physicochemical (pH, density), under controlled temperature conditions, and the microbiological ones. The results of this study showed that the tested cosmetic product is compatible with the plastic container; data obtained were comparable with the organoleptic and physicochemical test results obtained in the case of the control sample stored at room conditions.

Abstract: Purpose of the articleto carry out an epidemiological study on the use of sealing as a method of preventing dental caries and to assess the tightness and integrity over time of composite resins used to seal pits and fissures using the VistaCam iX intraoral fluorescence camera. Based on the premise that dentists do not have enough confidence in sealing pits and fissures as a method of preventing dental caries, we assessed if sealing is used in current practice as a prevention metod of tooth decay, and we measured, with high performance intraoral camera such as the VistaCam iX device, the tightness and integrity of composite resin seals.

Abstract: The aim of this study was to compare the biofilm formation on three types of dental crown materials using adenosine triphosphate (ATP) driven bioluminescence as an innovative tool for the rapid chairside enumeration of oral bacteria and assessment of oral hygiene. The study group included 60 patients with fixed prosthodontics, made of three types of dental crown materials (BioHpp - Bredent, Ceramics - VITA VMK Master, and Zirconia - Vita In-Ceram) from which we have collected 60 specimen values using a luciferase-based assay system (system SURE II). The values of ATP were obtained with System SURE II device and statistically analyzed with Anova and Wilcoxon Test. The lowest value was shown for Zirconia, comparing with ceramics and BioHpp, but in time we have seen the increase of ATP for all three dental crown materials.

Abstract: In the last years, health care professionals faced with an increasing number of patients suffering from wounds, burns and bedsores difficult to treat and heal. During the wound healing process, the dressing protects the injured area and contributes to the recovery of dermal and epidermal tissues. Because their biocompatibility, biodegradability and similarity to macromolecules recognized by the human body, some natural polymers such as polysaccharides (alginates, chitin, chitosan), proteoglycans and proteins (collagen, gelatin, fibrin) are extensively are used in wounds and burns management. The study presents a research of new semi-solid formulations of bio-composites based on chitosan extracted from the stone crab Pachygrapsus Mormoratus found on the Black Sea shores. The bio-composites were obtained from natural polymeric compounds, Chitosan (CT), hyaluronic acid (HA) and lanolin(L), to which silver sulfadiazine (S), was added. Several semi-solid formulations have been performed for which the antimicrobial activity on gram-positive and gram-negative germ cultures and the rheological behavior was studied. The bio-composites that were obtained provide an optimal micro-environment for cell proliferation, migration and differentiation, due to their biocompatibility, biodegradability, peculiar structure and good antimicrobial activity.

Abstract: The paper treats Finite Element Analysis (FEA) specific to the mechanical behavior of a structural layer cap type with polymer cellular cores within a pressure vessel. The layered composite structure comprises two outer polymer shells (synthetic glass/ plexiglass) and cellular polymer core with triangular shaped cells. This analysis uses the Autodesk Inventor 2016 Professional 3D design and modeling software, in conjunction with the FEA analysis program, ANSYS 14.5 - Workbench, using the Mesh module. Mechanical behavior of the structural models specific to the four types of test caps, each having different cellular polymer core (ABS, PLA, PC and CF, 3 and 5 mm thickness), is revealed through the analysis of the state of stresses and deformations and correlating the FEA simulation results with experimental testing. Since the analysis leads to quasi-equivalent results under identical conditions of application until the fracture of the caps, it is found that such an FEA approach of the mechanical system components occupies an important place in the modern design process, being one of the ways of identifying the deformation fields and equivalent stresses in the analyzed composite structures.

Abstract: This paper presents the solvents effect on the mechanical and thermal properties of films of styrene-butadiene and styrene-isoprene block copolymers with the majority diene phase, obtained by spin casting.

Abstract: The article presents the process of manufacturing by adding solid state material (thermoplastic extrusion) in order to achieve new composite deposition materials and to provide new models, raw materials and functional prototypes with superior mechanical features and characteristics. The authors describe the extrusion device as well as the parts manufactured of thermoplastic material.

Abstract: Placental blood circulation has certain features that allow the exchange of nutrients between the maternal and fetus blood, respectively allow exchanges of nutrients between the mother and the fetus. We studied 50 human placentas. 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, Timisoara, for over 50 years. The making of corrosion concoction followed the recipe of the laboratory using type AGO II plastic substances, differently coloured and then subjected to the corrosive action of hydrochloric acid. The model of corrosion preparations showed the distributions known as dichotomic and magisterial distribution. The normal development of placenta remains a major factor in the growth and development of the fetus, and maternal-fetal vasculature in the placenta is essential in this regard.

Abstract: In this paper we present a study that was conducted to determine the classification of causes that generate defects in products obtained by injection of plastic material. A classification of the causes of defects is made by applying a quality management tool - the Ishikawa diagram. The causes are grouped into M categories, for defects generated by the design process and for defects generated by the injection process. A new model of the diagram is created by composing two fish skeletons (model 4M + 5M). At the end of the paper, the importance of the Ishikawa diagram is shown.

Abstract: Collagen hydrolysers are three-dimensional polymeric materials with limited cross-linking and high hydrophilicity, having multiple medical applications. The most used collagen is the one extracted from bovine skin, which is now the industrial source of collagen. Due to the outbreak of some threatening diseases such as BSE, transmissible spongiform encephalopathy, foot-and-mouth disease, researchers have sought a safer alternative to collagen. This was the marine resource, which offered multiple opportunities to capitalize on clean sea-water raw material. This paper presents a comparative study of the physico-chemical properties of collagen hydrogels derived from collagen obtained from calf and skin from the Black Sea. Physico-chemical and spectrophotometric analyzes were performed to determine the structure. Studies have been conducted to analyze rheological behavior, antioxidant activity and antimicrobial activity. The total antioxidant capacity (ACL) is higher for collagen mixtures with 40% ethyl alcohol and shows higher values for fish collagen compared to calf collagen. Antimicrobial analysis shows that all collagen hydrogels show antimicrobial activity, both gram-positive (Staphylococcus aureus ATCC 6538P) and gram-negative (Escherichia coli ATCC 10536), which increases with increasing collagen concentrations.

Abstract: Postoperative pain is a common symptom in the postoperative period in patients treated for incisional hernia, often refractory to treatment. The purpose of the this paper was to conduct a comparative study on the need for analgesic medication in patients operated for incisional hernia through a classical open approach and a laparoscopic approach. In this respect, we performed a retrospective observational study over a period of 4 years in which we introduced 92 patients operated for incisional hernia in the Surgery Clinic No. 1 of the Emergency County Hospital Tirgu Mures. For the reconstruction of the abdominal wall we used prosthetic materials (surgical meshes). All patients included in the study received only metamizole sodium as analgesic medication. The patients studied were divided into two groups: group A (consisting of 57 patients where open, classic surgical approach was used) and group B (consisting of 35 patients treated using a minimally invasive laparoscopic approach). It was observed that on the day of surgery and during the first two postoperative days there are no statistically significant differences in the need for analgesic medication between the studied groups. Instead, starting with the third postoperative day, the need for analgesic medication is much lower in patients where laparoscopic surgical procedure was used than in those where open, classic surgical approach was used.

Abstract: The aim of the present study is to model the steady heat transfer of the engine polyamide intake manifold. Under the condition of a steady flow, the intake manifold wall temperature and the intake air temperature were measured to examine the effect of the thermal boundary layer on the heat transfer. Experimental data is used to generate the numerical model of airflow simulation through the intake manifold.

Abstract: Hepatocellurar carcinoma (HCC) is the most frequent primary hepatic tumor, the vast majority of patients have less than a 12 month survival rate. The aim of this study was to evaluate the efficacy of TACE in patients with HCC, based on a case series and literature review. The study included 12 consecutive patients with HCC who underwent surgical treatment (resection, liver transplantation ± resection) at the Department of Transplantation and Surgery, Semmelweis University, Budapest, during 2009-2015. All the patients received at least one TACE session. Patients with BCLC B-stage who benefit from TACE and another alternative therapy (eg, RFA) may be associated with or exhibit tumor stagnation, or tumor necrosis in most cases. In C BCLC stages, desperate cases - the two patients to whom TACE was the last therapeutic attitude, despite the predicted prognosis, TACE assured the prolongation of life and increased life quality. In the majority of patients in this study, stage A BCLC, chemoembolization was a therapeutic attitude that allowed subsequent liver transplantation (when it was not feasible initially due to tumor size) or liver resection in apparently inoperable cases. The arterial chemotherapy is the unanimously accepted indication in patients with stage B, BCLC. The data presented encourages us to opt for TACE with the intention of destaging BCLC and giving an operability character to the hepatic tumors (resection ± hepatic transplantation). In stage C BCLC, TACE can be a last attempt to improve the quality of life and to control tumor progression.

Abstract: This study aims to develop biodegradable and edible materials based on hydrocolloids and to analyze their physical and mechanical properties for use as food packaging. Edible packings were obtained from a hydrocolloid matrix (agar, starch, sodium alginate), plasticized with glycerol in different proportions (33.33% and 16.7% from the total amount of polysaccharides used). The physical and mechanical properties were analyzed. The best results were obtained with agar- sodium alginate packing, plasticized with the highest amount of glycerol.

Abstract: The character of the original paper is to provide electromagnetic radiation absorbing material that attenuation characteristics of the electromagnetic field very good, as compared to the absorbent materials studied to date. This paper presents results of research on processing, characterization and behavior of composite materials based on silicone rubber used for electromagnetic shielding. In this work silicone rubbers is reinforced with magnetic fillers (iron silicon). The obtaining of composite materials was with the aid of a doctor blade technique. Doctor blade technique is a coating technique widely used for producing thin films on large area surfaces. The samples were processed in the laboratory using a plated nettling (PN), that was impregnated with a silicone rubber based composite containing powder of iron silicon (SI). Were achieved measurements of the both parts of the materials obtaining. These have shown an electromagnetic shielding effectiveness the order of 3.35-41.62 dB (white face) and 3.53-41.42 dB (gray face), in 1-18 GHz frequency range according to SR EN 50 147-1:1999. The paper tries to identify an absorbent material with the ability to protect human beings of electromagnetic radiation that surround us every day and every moment. With the exponential increase in development of commercial, aerospace, military and scientific electronic devices in modern society, electromagnetic radiation is becoming the fourth public pollution after the air, water and noise ones.

Abstract: Large areas of S-E of Asia (Bangladesh), East of Europe (Hungary, West of Romania, Serbia), Nord and South America contain deep ground waters contaminated with arsenic. In these areas the quantity of arsenic in deep aquifers exceeds maximum allowed concentration of 10 µg/L. In order to use these water sources new adsorbent materials are required for their treatment. A composite material based on carbon and iron-oxide (used as surface modifier) present many advantages such as: chemical stability, higher removal efficiency, possibility of regeneration and very good selectivity for As(V) ions due to presence of iron-oxide particles onto the surface. The purpose of this study was to develop a new method to obtain a composite material using cellulose and soluble starch as carbon sources for the adsorbent material and iron chloride as precursor for the surface modifier. Produced composite material was characterized using several methods: TG-DTG, SEM, EDX, RDX and FT-IR. During experimental test obtained adsorbent material was used as adsorbent for As(V) removal form aqueous solutions. Arsenic residual concentration was measured using ICP-MS method. Maximum adsorption capacity obtained for adsorption experiments was 280 µg As (V)/g of adsorbent material.

Abstract: The purpose of the study was to evaluate the way in which bimanual and unimanual balanced balance values depend on the technical characteristics of using both Bosu ball surfaces in relation to three pressure levels: 0.6 atm., 0.4 atm. and 0.2 atm. The results have shown that steady manual balance is dependent on the characteristics of the equipment used. The lower the ball’s pressure, the balancebalance becomes worse. Testing the stable hand-balance on the round-up has scored better than the round-side down of Bosu ball.

Abstract: The occurrence and evolution of the disease depend on the properties of the organism, the cortical inhibition prevents the development of anaphylactic shock in humans. In some people, the increased and altered sensitivity manifests itself in the form of idiosyncrasy. In idiosyncrasy, the reactivity of the organism is altered from different substances of antigenic nature These substances can be food (milk, strawberries, eggs) or drug substances (iodine, iodoform, bromine, etc.) (drug idiosyncrasy whose symptoms are not related to the specific pharmacodynamic properties of the substance), plastics (prostheses, babies’dummy, etc.). The allergic reaction can be divided into two successive stages: a first stage of allergy, characterized by the formation of allergic type antibodies, their spread and fixation on certain tissues, and the second stage, of antigen –antibody, which represents the reaction In both stages there are both phases of immunological specificity (antibody production, antigen binding to the antibody) as well as non-specific phases in which the allergen and the antibody behave banal, non-immune (enter the body, circulate) or participate in reactions without immunological specificity (histamine release, etc.) The allergy therapy will appropriately include both specific methods and non-specific methods. Specific methods are only two: stopping the allergen input (allergen deficiency) and specific desensitization.Material and Method: A sample of 183 patients was studied in the present study between 2013 and 2017 with suspicions of hypersensitivity to dental materials for local or general symptoms. Results and discussions: A more severe allergy can be manifested in the dental office, is caused by the local anesthetic. The dentist has several local anesthetics, and through a well-done questioning, he will decide which type of anesthesia is the one indicated. For these reasons, an allergic reaction to the anesthetic is less common, but its manifestations are rather severe if it does not intervene in time. Conclusions:Dental biomaterials, in addition to mechanical and chemical resistance, should not contain toxic diffusible elements in the general circulation, elements with allergic or carcinogenic potential.

Abstract: The controlled lamination of thick sheets involves the use of algorithms for choosing the rolling parameters: the initial heating temperature, the lamination scheme (the distribution of the total thickness reduction on each rolling cage, the number of passes through each cage and the distribution of the thickness reduction on each passage, intermediate cooling - cooling time and speed), and the temperature of the product obtained at the end of the rolling. The complexity of the phenomena, which occur during the hot plastic deformation process and which must be sufficiently well mastered in order to obtain reproducibly the technical specifications imposed on the products with different destinations, is the justification for this work. The data provided by Arcelor-Mittal Galati was used to obtain the mathematical model. Equations that correlate the main mechanical characteristics with the chemical composition of the steel and the parameters of the hot rolling pattern used are presented.

Abstract: The worldwide increasing number of reports related to new cases of Breast Implant-associated Anaplastic Large Cell Lymphoma (BIA-ALCL) raises the interest of the scientific community in understanding the pathophysiology and the prognosis of these patients. This material presents the impact that BIA-ALCL exerts on the reconstructive options for patients who have undergone mastectomy. The research is based on data obtained from the analysis of a group of patients who have undergone 71 surgeries performed within the National Breast Reconstruction Program between 2015 and 2019. The statistical analysis revealed that 35.14% of the patients that were examined during the breast reconstruction consult refused the use of alloplastic techniques by invoking the potential associated risks described in the insufficient documentation of BIA-ALCL pathophysiology. Improving BIA-ALCL detection and reporting systems has led to an accelerated increase in the number of new diagnosed cases, determining the patients’ reticence towards the use of alloplastic reconstructive techniques.

Abstract: Noninvasive techniques, such as Magnetic Resonance Imaging (MRI) are becoming more used in the study of bone regeneration outcomes, in both animal models and human patients. Many studies have shown the potential of tissue engineering therapies to promote healing of skeletal injuries, but further research is needed to optimize these treatment options. This investigation is a continuation of other previous published studies, in which critical-sized bone defects created in the parietal bones of Wistar rats were filled with either bioglass or a biologic collagen scaffold seeded both with adipose-derived mesenchymal stem cells. The present study aims to present the applications of MRI in the assessment of the bone regeneration process in these previously created defects, at specific time intervals. MRI techniques are based on the differences between the spin-latice T1 and spin-spin T2 relaxation times of examined specimens or areas, compared to normal tissues. We measured the relaxation times specific to calvarial specimens with a Brukner Minispec. The results showed that the most favorable results were observed when a collagen scaffold seeded with stem cells was used. MRI enabled the detection of hard and even soft tissue changes, these findings suggesting that MRI could be an effective imaging modality for assessing changes in bone morphology and pathobiology. Furthermore, it can be used as an alternative to Computed Tomography in examining the role of various biomaterials used in bone healing, especially when ionizing radiation is contraindicated.

Abstract: In this study, the effect of polymers on the mechanical properties of ketoprofen extended drug release systems were studied. Many polymers are added in formulation of compressed tablets in order to improve the physicochemical characteristics of the drug release system. The samples were made in the form of cylindrical tablet about 9 mm in diameter, containing different mixtures of drug substances and excipients acording to seven formulations. Cylindrical tablets containing mixtures of ketoprofen and various types of polymers are made by direct compression method. Among the binders used were a series of different polymers like Kollidon va 64, hydroxypropyl methyl cellulose and sodium carboxyl methyl cellulose. Mechanical parameters such as hardness, mechanical strenght, friability and roughness were studied in order to determine how they are influenced by polymeric binders.

Abstract: Drilling of polymeric materials can be challenging when holes are produced in large scale due to the necessity of controlling the holes quality. This paper presents the effect of machining parameters on the hole quality, in terms of surface roughness and circularity error, in drilling of high density polyethylene, polyamide and polyacetale. The analysis of variance was performed in order to assess the significance of cutting parameter on the hole quality parameters. The experimental results indicate that different cutting conditions are to be employed in order to achieve the optimum surface roughness and circularity.

Abstract: The ionic conductivity, ionic viscosity as intrinsic properties of PMMA - TiO2 nanocomposites were investigated. The PMMA doped with 0.4% TiO2 nanoparticles has been used for 3D printed dentures manufacturing. A structural characterization using micro-computer tomography method was performed on 3D printed dentures, which have been permanently used for 12 months. The obtained results revealed good morphological stability of the materials in vivo, in the oral environment. The reinforced polymer matrix with nanotitania particles showed a dielectric constant and conductivity dependent on frequency, exhibiting improved characteristics when compared to the pure polymer matrix.

Abstract: This paper presents an experimental study on the potential use of new type of composite as insulation material. The composite material (AACW-UPR) was synthesised through mixture between the Autoclaved Aerated Concrete Waste (AACW) as filler and Unsaturated Polyester Resin (UPR) as matrix. Several samples of the composite material with different UPR concentrations (50 and 70 vol.%) and different AACW particle size (0.2-1 mm, 1.5-2.5 mm, 3-6 mm) were prepared. The thermal behaviour and the water absorption capacity of the AACW-UPR composite materials were studied. Also, the influence of water absorption capacity on thermal resistance and thermal conductivity was studied. During the investigations we noticed the following: good chemical compatibility between the AACW particles and the UPR matrix; a decrease in thermal conductivity for samples with 50 vol.% UPR and inserted particles size between 3-6 mm and an increase in water absorption capacity with the increase in the filler content in the matrix. The increasing water absorption capacity determined a decrease in thermal resistance and a reduction of the composite features as insulating material.

Abstract: This paper presents and discusses research conducted with the purpose of developing the use of solar energy in the heat treatment of steels. For this, a vertical axis solar furnace called at Plataforma Solar de Almeria was adapted such as to allow control of the heating and cooling processes of samples made from 1.1730 steel. Thus temperature variation in pre-set points of the heated samples could be monitored in correlation with the working parameters: the level of solar radiation and implicitly the energy used the conditions of sample exposed to solar radiation, and the various protections and cooling mediums.The recorded data allowed establishing the types of treatments applied for certain working conditions. The distribution of hardness, as the representative feature resulting from heat treatment, was analysed on all sides of the treated samples. In correlation with the time-temperature-transformation diagram of 1.1730 steel, the measured values confirmed the possibility of using solar energy in all types of heat treatment applied to this steel. In parallel the efficiency of using solar energy was analysed in comparison to the energy obtained by burning methane gas for the heat treatment for the same set of samples. The analysis considered energy consumption, productivity and the impact on the environment. Thanks to various data obtained through developed experiences, which cover a wide range of thermic treatments applied steels 1.1730 model, we can certainly state that this can be a solid base in using solar energy in applications of thermic treatment at a high industrial level.

Abstract: The interest in aesthetics of dental materials is becoming greater with time and dental ceramics have proven excellent aesthetic properties. The study investigated how does the oral environment and the different surface finishing affect the optical properties and roughness of two types of ceramic, obtained using the heat- pressed method. Results showed that immersion has some influence on the optical and roughness of the two types of ceramics, but the major influence is made by the surface finishing and the type of ceramic. Lithium disilicate ceramic proved to have better optical properties compared to feldspathic ceramic. Roughness values showed that the parameters(Ra and Rz) were influenced by the surface finishing for both type of ceramics.

Abstract: The purpose of this study was: Structural characterization of two commercial nanocomposite materials (Premise ™/Kerr Corp and Tetric EvoCeram®/ Ivoclar-Vivadent); Evaluation of the marginal adaptation and adhesive interface achieved with two commercial adhesive systems (Optibond SoloPlus ™/Kerr Corp and G-Bond ™/GC). Investigation was done using electronic scanning microscopy (SEM).

Abstract: Medicinal plants continue to be of real interest to researchers in interdisciplinary fields such as chemistry, pharmacy, medicine. Due to the metabolites in which it abounds, the plant material can successfully represent both a prophylactic and curative treatment. At present, countless studies, both in vitro and in vivo, are conducted to elucidate the pharmacological effects and establish the mechanisms involved. The actual experiment was purposed to evaluate the activity of raw birch bark, apple pomace and olive leaves extracts rich in triterpenes, formulated as PLGA nanoparticles, on normal/healthy different cell lines immortalized and of primary origin, such as keratinocytes, dermal fibroblasts, and gingival fibroblasts.

Abstract: Given the structural resemblances between glass fiber and asbestos, it is important to understand the mechanisms through which exposure to glass fibers may affect the respiratory system. To study the effect of glass fiber on rat lung through intratracheal exposure, considering the subject’s weight variation, together with haematological parameters, C-reactive protein (CRP), total number of lymphocytes, and IL8 concentration in bronchoalveolar lavage. We performed an intratracheal instillation study on four groups of 8 randomly selected Wistar rats, by administering 3 different doses of glass fiber. The hematocrit value was an indirect indicator of chronic hypoxemia; leukocytes and the C-reactive protein assessed systemic inflammation, and total number of lymphocytes and IL8 concentration in bronchoalveolar lavage fluid determined the lung’s inflammatory response. Weight variation evaluated in all 8 measurements revealed no statistically significant changes (p=0.768). The decrease in mean blood leukocytes was interpreted in relation with the glass fiber dose, with a statistically significant difference between the study groups (p=0.003). Statistically significant differences were found in the CRP values, with dose correlations (p[0.001). The bronchoalveolar lavage fluid showed increased levels of IL-8 (p[0.05), and decrease of lymphocytes (p[0.001) in correlation with the administered glass fiber dose. The inflammatory response following exposure to glass fibers in rats is correlated with administrated glass fiber dose. The alterations described as a result of intratracheal glass fiber instillation could predict the effects which occupational exposure to glass fiber may produce in humans.

Abstract: Oestrogen hormones play key roles in the human body, are involved in complex mechanisms, both beneficial and unwanted. Because semisynthetic oestrogens are commonly used today in various hormonal therapies, they has inevitably been linked to the appearance of certain carcinogenic processes, which are primarily based on oestrogen-based drugs, either as initiators or promoters. A promising alternative that can help reduce unwanted effects is to capture the active substance in a polymeric matrix that is capable of retaining its biological activity. In this study, activity on the viability of breast cancer cells with expressed oestrogen receptors of a polymeric formulation with ethinylestradiol and polylactic acid was evaluated.