bluuebunny/crossref_metadata_2025 huggingface dataset:
OPTIMIZATION OF OAK TREE STANDS GROWING IN CONDITIONS OF VINNYTSIA REGION
Authors: Matusiak Mikhaylo
Published: January 2020

The main part of forest plantations of Vinnytsia region is occupied by plantations with predominance of pedunculated oak (81%).
Most of oak stands that grow within the region, in terms of plantings composition, correspond to the types of forest plant conditions. Under those circumstances, most tree species show high growth rates. The area of plantations of the II class qualitymakes up 94.7%, 4.9% – of the ІІI class quality and 0.4% – ofthe ІV. The largest area (57.1%) is occupied by plantations with the density of 0.7, slightly smaller (31.8%) – with the density of 0.8, and plantations with the density of 0.9 to1 occupy the area of 3.5%, with the density of 0.6 – 6.3%; 0.5 – 0.8%; 0.4 – 0.3%. Despite the systematic intermediate cutting, which was carried out in order to preserve the pedunculated oak, European ash and other valuable species as a part of 92-132-year-old stands, the highest number of the preserved trees belongs to hornbeam (36.5-64.9% of the total numberwere in 19 plantations of Vinnytsia region). Only on two plantations 9.7-14.9% of hornbeam out of the total number of tree species was found.
According to biological and ecological properties, the optimum proportion of European ash in plantation is 25-30% of the total number of trees provided they are evenly distributed over the area. According to the research conducted, there was no ash trees in two stands, in one plantationonly eight trees of ash were preserved, in the next three – 100-109 trees and in the rest – from 26 to 84 (7.4-25%) of the total number of trees, what lies within its coenotic optimum.
In four plantations the mazzard cherry was preserved, in one stand – one tree, in two other – 9-11 and in the next one – 20 trees. Linden was preserved in 14 plantations –from 1 to 44 trees, and in one stand there were 90 trees. Wild service tree survived in two plantations – one per every stand.
It was determined that composition of plantations significantly affects the stock of the stem wood, especially the yield of valuable assortments and their cost. Increasing the number of trees up to a certain limit of pedunculated oak, European ash and other valuable species in mixed stands, including natural seed plantation, placed in fresh oak forests, leads to the increase of the stock of stem wood, valuable assortments and their cost.
OVERSPREADING OF VISCUM ALBUM L. ON HONEY PLANTS IN THE CONDITIONS OF VINNYTSIA REGION
Authors: Razanov Serhii , Nedashkivskyi Volodymyr
Published: January 2020

The intensity of damaging the nectar and pollen trees of forest lands, parks and woods in the conditions of Vinnytsia region has been studied. It has been found that in the zones of the highest local overspreading of Viscum album L. on the nectar and pollen trees, the following sequence of their damage is observed, in particular, in the conditions of forest lands: Tilia cordata L.-Tilia platyphyllos L. -Acer platanoides L.- Acer tataricum L.; in the parks: Acer platanoides L.- Acer tataricum L.- Tilia cordata L.- Acer campestre L.- Tilia platyphyllos L. - Robinia pseudoacacia L.; in the woods: Robinia pseudoacacia L. - Tilia platyphyllos L. - Acer tataricum L. It depended both on the composition of the nectar and pollen trees and their number in the area of distribution of the parasite.
It was found that the level of damage to the nectar-dust-bearing trees of forest lands, parks and forest strips was respectively within 11.7% - 34.6%, 28.5% - 85.5% and 38.4% - 84.8%.
Characterizing the intensity of distribution of white mistletoe within the forest lands, it should be noted that damage to the Tilia cordata L. – 34,6%, Tilia platyphyllos L. – 23,5%, Acer platanoides L. and Acer tataricum L.– 25,0% and 11,7% . In the conditions of park plantations, damage to Viscum album L.: Tilia cordta– 51,6%, Tilia platyphyllos L. – 52,9%, Viscum album L. – 28,5%, Acer platanoides L. – 85,5%, Acer campestre L. – 71,4% and Acer tataricum L.– 63,6%.
Analysis of the intensity of Viscum album L. distribution on the nectar-pollen-bearing trees of the forest area under the highways showed that this parasite was damaged: Tilia platyphyllos L. – 38,4%, Viscum album L. – 84%, Acer campestre L. – 42,8%.
The intensity of damage to nectar-pollen was found to depend on the dominant tree species in the area of local Viscum album L.
In the woodland, a greater proportion of the nectar-bearing trees were Tilia, in the park zones – Acer platanoides L. and in the forest strips -– Viscum album L., at the same time, and a larger percentage were observed of damaged trees in these species.
The distribution of Viscum album L. depended not only on the breed of nectar-pollen-bearing trees, but also on the number of trees of a particular variety in the area of their local damage by this parasite.
RISK CHARACTERIZATION IS THE FOURTH STAGE OF ECOLOGICAL RISK ASSESSMENT
Authors: Monarkh Veronika
Published: January 2020

Risk values have been obtained using a situational risk model that enables to identify the storage buildings (objects) on the territories where special measures should be taken to reduce and eliminate pollution. The research results clearly prove availability of severe local sources of contamination of agricultural lands with organochlorine pesticides. There is a risk of contamination of other environmental objects with hazardous substances and a negative impact of toxic substances on human health. Migration of pesticides from the soil into agricultural products and drinking water has been identified. The risk characterization stage assesses the frequency and magnitude of toxic effects, their reversibility or irreversibility. One of the methods used is the method of comparison of the results obtained with similar projects and studies. An important condition for the introduction into the general farming use of territories in the zones affected by the former pesticide and agrochemical storages in these settlements is the search for the methods of restoration and purification of soils of these territories from xenobiotics. Only after conducting the work on soil purification and availability of the inspection results showing positive changes, it will it be safe to grow agricultural products.
Tourist poverty as a cultural and humanitarian determinant
Authors: Pecheniuk Alla
Published: January 2020

Purpose. The aim of the article is improvement and complementation of theoretical aspects of the study of tourist poverty.

Methodology of research. The following methods are used during the study: comparison - to determine the dynamics of outbound and domestic tourist flows of our state; systematic approach - when considering tourism poverty as a system that consists of a certain number of interrelated elements of both material and cultural-humanitarian nature and comprehensively influences the effectiveness of tourism development of the country; scientific abstraction - with the isolation in the phenomenon under study of a strong, stable, typical connection, which allowed to form in a generalized way the characteristic features and to determine the problems of cultural and humanitarian development.

Findings. Tourist poverty of the population has been investigated for the purpose of revealing the connection with the educational sphere and with the sphere of cultural and humanitarian development of citizens. It is established that tourist poverty is not only related to material aspects, and requires close interaction with the educational environment. It has been proven that the result of tourist poverty is the tourist marginalization of the population. The characteristic features of tourist poverty from the point of view of material and worldview characteristics are highlighted. The problems of cultural development have been identified and the causes of cultural deconsolidation of society and the formation of tourist poverty have been identified. The ways of strengthening of unity in the society and overcoming the humanitarian-cultural tourist poverty are proposed.

Originality. The author defines the concept of "tourist marginalization" - a process of reducing tourist activity due to economic and humanitarian factors, characterized by an increase in the number of citizens who do not participate in tourist activities, are socially passive, does not position itself with certain social groups, without clear identification groups or tourist interests that are included in tourist consumption due to media background agents.

Practical value. The results of the study can be used to develop an effective national strategy for the cultural, humanitarian and tourism development of the state, which will ultimately prove to be a significant social effect.

Key words: tourist poverty; social inequality; cultural and humanitarian development; cultural competence; cultural deconsolidation.
Conducting judicial economic expertise related to bringing bankruptcy entities
Authors: Horlachuk Oleksii
Published: January 2020

Purpose. The aim of the article is consideration and improvement of methodical techniques of forensic economic expertise in conducting research on the signs of bringing economic entities into bankruptcy.

Methodology of research. The theoretical and methodological basis of the research is the scientific works of expert economists, legislative and regulatory acts. The following general scientific methods are used in the course of the study: analysis and synthesis, generalization – to determine the signs of bringing economic entities to a stable state of financial insolvency; abstract and logical – to form conclusions and suggestions. In addition to general research methods, special methods are also used: economic and mathematical modelling – to substantiate methodical techniques in the analysis of signs of bringing economic entities into bankruptcy.

Findings. The essence and signs of bringing economic entities to sustainable financial insolvency, which is carried out by various veiled methods and schemes in their financial and economic activity, are considered. The use of this type of judicial economic expertise in the analytical component of the indicators characterizing the dynamics of fixed assets and long-term receivables, which is reflected in the balance sheets of the debtor enterprise, is substantiated.

Originality. There has been further development of a study of methodological techniques for analysing the features of bankruptcy of economic entities.

Practical value. The proposed methodological techniques can be used to improve the analysis of the signs of bankruptcy in court expert activity, as well as enterprises of different forms of ownership and management to take preventive measures, increase the efficiency of their activities.

Key words: bankruptcy; bringing to bankruptcy; insolvency; debtor; accounts receivable; liquidity; financial status.
Recovered Polypropylene Composites with High Impact Strength
Authors: Ghioca Paul , Iancu Lorena , Grigorescu Ramona Marina , Spurcaciu Bogdan , Rapa Maria , Cincu Cornel , Pica Alexandra , Matei Ecaterina
Published: January 2020

This paper presents a modification study of recovered polypropylene by melt alloying with a styrene-isoprene block-copolymer blend, thus ensuring the optimum conditions to obtain polypropylene composites with performance impact strength.
3D Printing of a Mandibular Bone Deffect
Authors: Gabor Alin , Hosszu Tiberiu , Zaharia Cristian , Kozma Alexandru , Cojocariu Andreea Codruta , Negrutiu Meda Lavinia , Szuhanek Camelia , Sinescu Cosmin
Published: January 2020

The aim of this study was to achieve a polymeric scaffold, ex-vivo, using 3D printing technology and then subjecting it to various tests to check its optimal property. Initially there was selected a lower jaw with a bone defect that would have prevented any treatment based prosthetic implant. The mandible was first scanned using an optical scanner (MAESTRO DENTAL SCANNER MDS400). The scanning parameters using optical scanning system are: 10 micron accuracy, resolution 0.07 mm, 2 rooms with High-Resolution LED structured light, two axes. The scan time of the mandible was 4-5 min. Later the same mandible was scanned using CBCT�s CRANEX 3DX. The images obtained using CBCT�s were correlated with those obtained by optical scanning. Further on, there was achieved the digital design of the future scaffold with the conventional technique of wax addition directly on the mandibular bone defect. After that, this was again scanned using scanning system MAESTRO DENTAL SCANNER MDS400, and using CBCT�s CRANEX 3DX. The images obtained were correlated with all the scanned images of original mandible bone defects. There were made two polymeric scaffolds using 3D printing system an (D20 Digital Wax System 3D Printer). After printing, scaffold sites were introduced for 30 minutes in an oven curing. Later the pieces obtained were processed to remove small excesses of work. There were obtained 3 blocks of polymers that have a good adaptation to the bone profile. Often, in oral implantology and maxillofacial surgery appear bone defects. They prevent an optimal treatment of bio-functional and aesthetic restoration. Using 3D printing technology one can achieve scaffold sites of different biocompatible materials that have optimal properties to replace bone defect and restore the defective area. These scaffold sites have an intimate adaptation to the defect. 3D printing techniques used to restore bone defects can quickly and efficiently give the possibility to have a successful implantology prosthetics treatment.
Use of Trichloroacetic Acid in Treating Facial Hyperpigmentation
Authors: Jecan Radu Cristian , Nicolau Alexandru , Florescu Ioan Petre , Ardeleanu Valeriu , Berbece Sorin
Published: January 2020

This paper aims to present the benefits and results of using TCA of high concentration of 50%, in conjunction with the presentation of adverse reactions and complications. The study was conducted in Arestetic Clinic Galai during the period 10 Dec. 2015-1 Nov. 2016, on a group of 12 patients, of which 10 women and 2 men. The product used was Easy TCA 50% manufactured by SkinTech laboratories. Three coats of TCA were applied at intervals of 4 minutes each. The end result was assessed at 21 days, when the entire surface of the skin was peeled and re-epithelized. Patients were asked to assess the degree of satisfaction on a scale of 1 to 10, with 1 being the least satisfactory and 10 being the most satisfactory. As a result of this assessment, 10 patients rated the degree of satisfaction with 10 (83%) and 2 patients rated the degree of satisfaction with 9 (17%), with an average degree of satisfaction of 9.83. At 21 days, dyschromias and hyperpigmentations completely disappeared in 9 patients, while a female patient and 2 male patients still presented with barely noticeable spots. These three persons were subjected to the second peeling after 2 months, this time in two layers, and these hyperpigmentations disappeared at the end.
Effect of Unmodified and Modified Nanocrystalline Cellulose Reinforced Polylactic Acid (PLA) Polymer Prepared by Solvent Casting Method Morphology, mechanical and thermal properties
Authors: Kasa Siti Norbaya , Omar Mohd Firdaus , Abdullah Mohd Mustafa Al Bakri , Ismail Ismarul Nizam , Ting Sam Sung , Vac Sebastian Calin , Vizureanu Petrica
Published: January 2020

The positive attributes of excellent biocompatibility and biodegradability of biocomposites with the addition of versatile nanocellulose from agriculture wastes have provided plenty opportunities for further development of functional biocomposite in various fields. Therefore, solvent casting was selected as a reinforcement method in order to produce biocomposite comprise of nanocrystalline cellulose and PLA polymer. Modification of nanocrystalline cellulose through acetylation reaction was conducted upon reinforcement to reduce its surface polarity and hidrophilicity. Biocomposite films prepared at various unmodified (uNC) and acetylated nanocrytalline cellulose (aNC) loading were exposed to morphological (FESEM), tensile test and thermal analysis (TGA). Reinforcement of aNC shows a better dispersion in PLA polymer due to the decreasing of surface polarity, thus increasing inter-facial interaction between both materials. This is proven by greater performance of biocomposite films in tensile strength, Young�s modulus and thermal stability of aNC reinforced PLA as compared to uNC reinforced PLA. Overall, it can be concluded that these research findings can widen the scope of biocomposites research area and have significant implications for the commercial application of biomass products.
Biomaterials: Polylactic Acid and 3D Printing Processes for Orthosis and Prosthesis
Authors: Miclaus Roxana , Repanovici Angela , Roman Nadinne
Published: January 2020

Since the development of 3D printing, over the past decades, the domain of application has evolved significantly! Concerning the orthosis and prosthesis manufacturing, the 3D printing offers many possibilities for developing new medical devices for people with disabilities. Our paper wish to synthetize the main 3D printing methods and the biomaterial properties which can be used in orthosis and prosthesis manufacturing, like polylactic acid or acrylonitrile butadiene styrene. Fused Deposition Modeling and Stereo lithography are most used for medical devices manufacturing and usually using polylactic acid, considering the properties of this polymer and de organic componence.
Influence of ZnO Nanoparticle Size and Concentration on the Polysulfone Membrane Performance
Authors: Pintilie Stefan Catalin , Tiron Laurentia Geanina , Birsan Iulian Gabriel , Ganea Daniel , Balta Stefan
Published: January 2020

The activity of using membrane technology has developed fast in the treatment of wastewater, drinking water and process water production. The main challenges in membrane filtration are fouling reduction, permeability increase and high efficiency in retention. The best example of membrane enhancement is increasing hydrophilicity. Nanoparticles have been proven that their presence in the membrane matrix increases the water affinity significantly. Although the zinc oxide nanoparticles have a positive effect over the membrane performance, the influence of zinc oxide (ZnO) nanoparticle size has not been studied enough. Two sizes of nanoparticle of ZnO and three concentrations were used for the preparation of composite polysulfone ultrafiltration membranes. The effects of the ZnO nanoparticles in the membrane matrix on the permeation properties, flux stability and retention were tested. SEM, EDX, porosity and contact angle measurement were conducted in this article, also. The experimental results indicated that ZnO-PSf composite membranes exhibits significant differences in the membrane properties due to nanoparticle addition and regardless of their size it leads to an increase in hydrophilicity, flux, permeability, retention and porosity. Decreasing the nanoparticle size leads to an increase in membrane performance.
Side-Effects of Polyurethane Ureteral Stents with or without Hydrogel Coating in Urologic Pathology
Authors: Grigore Nicolae , Pirvut Valentin , Mihai Ionela , Hasegan Adrian , Cernusca Mitariu Sebastian Ioan
Published: January 2020

Ureteral stents represent one of the most utilized medical device in urology, as a minimally invasive alternative to preserve urine outflow. The ideal ureteral stent which combines long-term efficacy with a very low rate of side effects is still missing from the urologist armamentarium. The main material for ureteral stents production is polyurethane. In order to improve the side-effects and complications of polyurethane stents, special coatings were developed. The aim of this study is to evaluate short-term side-effects and complications of different polyurethane stents with or without coating used in urologic field.
Flexural Strength of Single Polymer Polyester Composites as a Measure of Material Degradation
Authors: Gawdzinska Katarzyna , Nabialek Marcin , Bryll Katarzyna , Szymanski Pawel , Sandu Andrei Victor
Published: January 2020

The study compares flexural strength of single polymer polyester composites. Composites under examination had the form of laminates differing in the content of the reinforcement phase and the type of material subject to simulated absorption of distilled water and sea water. Simulation tests of distilled water and sea water absorption for single polymer polyester composites with 5% to 20% reinforcing phase were made in accordance with the PN-EN ISO 62:2008 standard. The determination of the measure of degradation of the composites, the magnitude of the bending stress, was conducted in accordance with the PN-EN ISO:178 standard. This work is part of a research relating to the quality and recycling of single polymer composite materials. The testing part of the research is aimed to define the properties of examined materials before they are used commercially in specific products.
Fabrication of Novel Silk Fibroin - LDHs Composite Arhitectures for Potential Bone Tissue Engineering
Authors: Galateanu Bianca , Radu Ionut Cristian , Vasile Eugenia , Hudita Ariana , Serban Mirela Violeta , Costache Marieta , Iovu Horia , Zaharia Catalin
Published: January 2020

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.
Railway Vehicle Pneumatic Rubber Suspension Modelling and Analysis
Authors: Spiroiu Marius Adrian
Published: January 2020

The pneumatic elastic elements are widely used in the secondary suspension of modern railway vehicles due to their important advantages compared to the conventional ones. In the present paper, the modelling and analysis of the pneumatic suspension is approached, taking into account the main elements, pneumatic enclosures and rubber elements. The analysis performed investigates the influence of relevant parameters on suspension stiffness and on its dynamic response.
FEM Analysis of Stress in Non-carious Cervical Lesion Restoration with Four Different Restorative Materials
Authors: Beresescu Gabriela , Ormenisan Alina , Comaneanu Raluca Monica , Veliscu Andreea Marilena Carp , Manea Marinela Minodora , Ion Razvan
Published: January 2020

The purpose of this study was to evaluate the behavior of four restorative materials in non-carious cervical lesions when subjected to exterior stresses of different magnitude. A plane model reproducing a vestibular and lingual section of the lower canine was created. The finite elements are of a two- dimensional type (2D) - quadrilater. Four restorative materials were used: Vitrebond, Dyract AP, Vitremer, Fuji IX. All materials were considered to be isotropic and elastic. Nodal charges were of 40 degrees to vertical, applied on the vestibular side at h=8.993mm to gingival crest, of increasing magnitudes:20, 40, 60, 80, 100, 120, 140, 160 N. The results of this study showed that after restoration stress values in all the elements are (with minimal differences) similar to those in the healthy tooth; a correct restoration leads to normal functioning of the tooth. It can be considered that particular types of restoring materials should be used in particular lesions to be restored, depending on the location of the lesion and the elastic characteristics of the materials and tooth structure. A correct restoration leads to normal functioning of the tooth.
The Influence of the Characteristics of Plastic Materials Used in the Performance of the Thoraco-Lumbar Orthoses
Authors: Nanu Constantin , Poeata Ion , Popescu Cezar , Eva Lucian , Toma Bogdan Florin , Toma Stefan Lucian
Published: January 2020

The aim of the paper is to identify the of optimal plastic type used in obtaining thoraco-lumbar orthoses - used in the treatments of comminutive fracture, of burst fracture type of the vertebrae in the lumbar area. For this purpose, with the help of Finite Element Analysis (FEA), a theoretical study was carried out on the influence of elastic properties of plastics, used in the achieving of lumbar orthoses, on the state of tension and on the local displacements of the bone fragments from the traumatized area under the condition of the movement from the base of extension and flexion. In the study the force of flexion, the force of extension and the elastic modulus of plastic material varied on three levels. The theoretical results obtained were completed with clinical trials carried out on a total of 26 patients who suffer thoraco-lumbar comminutive fracture, burst fractures type, at vertebra T11 and were immobilized in Boston-type plastic orthoses made of: polypropylene (PP), rigid vinyl polychloride (PVC-D) and polytetrafluoroethylene (PTFE). As a result of observations, it was found that the use of an orthesis made from rigid plastic material, although it appears higher stresses in the traumatized zone, the displacements of bone fragments are smaller, the pains is higher in the fractured zone, the angle of kyphosis (LKA) close to the normal value and a better mobility of the spine (ODI indicator).
Assessment of Delamination in Tensylon� UHMWPE Composites by Laser-induced Shock
Authors: Alil Luminita Cristina , Arrigoni Michel , Deleanu Lorena , Istrate Marcel
Published: January 2020

Ultra-High Molecular Weight Polyethylene (UHMWPE) composites are the result of recent developments in material research for ballistic protection due to their ability to absorb the kinetic energy of the bullet by various mechanisms of dissipation, among which an important one is delamination. In order to study this mechanism independently, the laser induced shock wave testing procedure has been used on thin Tensylon� laminate samples. Laser-induced shock represents a modern approach that can be used for assessing the interlaminar bond strength between two plies of a composite material, in dynamic conditions, at high strain rates representative for a ballistic impact. Through this technique, a delamination failure stress threshold can be determined. In the present work, the laser induced shock technique was applied on the commercial UHMWPE material called Tensylon�. The delamination threshold of this material was determined by using the Novikov approach, and, compared to the literature, the results match the values determined by other means of measurement.
Phenotypic Study and Sensitivity to Anti-Infective Chemotherapy of Bacterial Strains Isolated from Cutaneous-Mucosal Infections
Authors: Vaduva Delia Mira Berceanu , Velimirovici Dana Emilia , Vaduva Marcel Mihai Berceanu , Stanga Livia , Petrescu Horatiu , Rada Maria , Cipu Daniela , Vaduva Bianca Manuela Berceanu , Radulescu Matilda
Published: January 2020

Skin- and mucosal infections, especially purulent, can often cause diagnostic and treatment problems. Therefore, we intend to conduct a microbiological study of isolated bacterial strains from ambulatory patients with various cutaneous-mucosal infections. In isolated strains we determined the sensitivity to antibiotics and we established the phenotypes of resistance in which they fall. We took in account 98 strains isolated by a private laboratory in Timisoara between January 2016 and December 2017. After bacterial identification, sensitivity testing to antibiotics was realized using Kirby-Bauer disc diffusion according to the CLSI standard. Antibiogram was performed for all strains except for Streptococcus pyogenes. By interpreting the antibiograms, the phenotypes of resistance were determined. Most infections were caused by Staphylococcus aureus. In order of frequency following strains were isolated: Staphylococcus aureus (75.52%), Streptococcus pyogenes (11.22%), Pseudomonas aeruginosa (7.14%), E. coli (4.08%) �i Enterobacter spp. (2.04%). S. aureus strains were resistant to penicillin in 94.60% of cases. We observed a higher sensitivity to oxacillin (87.84%), tobramycin (86.49%), gentamycin (87.84%), ciprofloxacin (83.78%) and clindamycin (89.20%). Most strains of S. aureus were of phenotype Peni-R Meti-S (82.44%). 12.16% were of phenotype Peni-R Meti-R (MRSA) and only 5.40% were sensitive to betalactams (Peni-S Meti-S). Gram-negative bacilli strains (Pseudomonas aeruginosa, E. coli, Enterobacter spp.) were less resistant, all being wild strains. Determining antibiotic resistance phenotypes is necessary in order to be able to make the right decision when choosing anti-infectious treatment, but also to prevent the selection of multi-resistant bacterial strains. The presence of MRSA at a rate of 12.16% is an alarm signal because the MRSA strains are multi-resistant to antibiotics with cross-resistance to the betalactams. Resistance usualy extends also to other classes of antibiotics. For a correct diagnosis and treatment, the results of the bacteriological testing need to be corroborated with the clinical signs.
Frozen Stresses in Shape Memory Polymer Composites
Authors: Tedde Giovanni Matteo , Santo Loredana , Bellisario Denise , Iorio Leandro , Quadrini Fabrizio
Published: January 2020

Shape Memory Polymer Composites (SMPCs) are a class of smart materials in which the structural properties of long-fiber polymer-matrix composites and the functional behavior of Shape Memory Polymers (SMP) are combined together. In this study, the frozen stresses resulting from fixing a deformed shape have been investigated. Two different samples were manufactured, with and without significant shape memory properties, and a three point flexural test equipment was used in order to fix a deformed shape. The forces and the resulting stresses were measured during the samples deformation and after the shape freezing. The experimental tests have shown that the shape memory sample has a better ability to fix a deformed shape, since its frozen stress is higher in all the tests.
Effects of Micro-Textured Polystyrene Substrates by Compression Molding on Cell Adhesion and Proliferation
Authors: Bellisario Denise , Quadrini Fabrizio , Santolim Gustavo , Tedde Giovanni Matteo , Caputo Valerio , Spitalieri Paola , Sangiuolo Federica , Santo Loredana
Published: January 2020

Surface chemistry and micro-nanoscale topography of biomaterials can significantly influence tissue engineering and cell biology. In this study, polystyrene (PS) Petri dishes were subjected to microtexturing by compression molding process, which resulted in three-dimensional (3D) microscale surface topographies. Three different micropatterned surfaces were fabricated using bronze sintered molds with different mean pore pitch sizes. The surface changes and the morphological aspects were analyzed by 3D surface analyzer. The dishes were then used to investigate the cell behavior of Mouse Embryonic Fibroblasts (MEF) P4 cells. The surface micropatterning have affected in different ways the MEF cell adhesion and proliferation, related to the morphological changes in comparison with unmodified PS. At the increasing of the sintered particle dimensions of the mold, the cavities dimensions on the molded Petri increase and also the cells adhesion in the cavities seems to increase independently from the roughness inside them.
Processing Conditions of Expandable Graphite in PP and PA Matrix and their Performance
Authors: Sover Alexandru , Marzynkevitsch Stanislav , Munack Bastian
Published: January 2020

Polypropylene (PP) and polyamide (PA) polymers are used in different situations where they provide a flame retarding effect to meet safety standards. The expandable graphite as an additive for polymer materials has a good flame retardant effect and it does not harm the environment. The processing of this additive is presented for those two different polymers. Compounds with proportions of 10, 20, 30% of this additive were prepared in order to investigate the processability and flame retarding effect of PP and PA samples. The results show that the process conditions differ greatly between the polymers used in higher proportions. The improvement of the flame retarding effect was observed for both polymer compounds with expandable graphite. The plastics flammability standard UL 94 V0 could be achieved for the PP compound in all additive proportions and for the PA compounds only above 20%. The processing of the PP compound with co-rotating twin-screw extruder and an injection moulding machine takes place works well and provides a good homogenous mixture. The PA compound could not be processed at a higher additive content by the extruder. Special screw configuration is necessary to process this polymer compound. Also the flame retardant effect was inferior to the PP compound. The mechanical properties of the compounds decrease with the increasing additive content, particularly the impact strength of the samples.
Antibiotic Encapsulated Nanomaterials with Application in Medical Area
Authors: Luca Alina Costina , Duceac Letitia Doina , Mitrea Geta , Ciuhodaru Madalina Irina , Ichim Daniela Luminita , Baciu Ginel , Banu Elena Ariela , Iordache Alin Constantin
Published: January 2020

Novel materials belonging to the class of anionic clays are synthesized by investigating their properties at nano scale. Thus, hydrotalcites or layered double hydroxides (LDHs) were used as drug delivery carriers in order to prevent or to treat infections produced by some pathogen agents. Their physical and chemical properties allow them to include different molecules in the interlayer space and then to ensure their transport to the target. The current work reveals the obtaining of nanohybrid compounds type amoxicillin/clavulanic acid-layered double hydroxides (Amox/CA-LDHs) followed by structural and morphological characterization of these nanostructures for future applications as drug controlled release systems. IR spectroscopy and Scanning Electron Microscopy pointed out LDHs ability to incorporate the medicines without modification of therapeutic activity.
Effect of Liquid Detergents on the Biochemical Parameters of Some Plantlets
Authors: Cretu Romica , Circiumaru Adrian , Murariu Gabriel
Published: January 2020

This article reports an environmental study concerning the liquid detergent contamination and its impact on some plantlets, e.g. Phaseolus vulgaris and Petroselinum crispum. In this context, this study focuses on specific modifications of the physical-chemical and biochemical characteristics of some plantlets induced by liquid detergents present in the soil, both bio-based and without environmental compatibility. The results of this study showed that a decrease (over 60%) in total chlorophyll per fresh weight could be solely due to the presence of non-biodegradable liquid detergents in soil, in various concentrations: 0.125%, 0.25% and 0.5% (wt/wt), calculated on water mass. On the other hand, the action of the detergents on the plantlets has revealed a decrease in the catalase activity in the case of both types of detergents.
Interaction Between Values of Anthropometric Body and Static Balance Related to the Characeristics of the Three Plastic Fitness Equipment
Authors: Badau Dana , Badau Adela , Clip Adriana
Published: January 2020

The study aimed to highlight how unipodal stable equilibrium values are depending on the technical characteristics of plastic fitness equipment in relation to some anthropometric indices in order to optimize the physical potential. The best results recorded for the static balance test for both legs was on the Stability Disc, followed by Balance Board executions, and the weakest results were obtained on the Bosu Ball. The executions on the right leg were superior to executions on the left leg.
Structural Investigations on Poly(methyl methacrylate) Various Composites Used for Stereolithographyc Complete Dentures
Authors: Totu Eugenia Eftimie , Cristache Corina Marilena , Isildak Selim , Tavukcuoglu Ozlem , Pantazi Aida , Enachescu Marius , Buga Roxana , Burlibasa Mihai , Totu Tiberiu
Published: January 2020

The present paper is focused on analyzing if appropriate adhesion between the polymeric matrix and titania filler nanoparticles is obtained for the PMMA-TiO2 photo-curable dental material, suitable for application in RP - stereolithography (SLA) for complete denture manufacturing. It was found that different amounts, between 0.2% and 2.5 % (w/w%), of added titanium oxide nanoparticles slightly modify the structural behavior of the PMMA polymeric matrix. The material characterization was carried out using FT-IR and microscopy techniques.
Poly(methyl metacrylate) Nanocomposites for Two-piece CAD/CAM Solution as an Alternative to Monolithic Removable Prosthesis
Authors: Pantazi Aida , Totu Eugenia Eftimie , Dorobantu Dorel , Cristache Corina Marilena , Enachescu Marius
Published: January 2020

The aim of the present paper was to characterize the new pink PMMA doped with 0.4% TiO2 nanoparticles utilized for denture base manufacturing as alternative to the one-piece, single color material for removable denture. The PMMA base material was structurally characterized through XRD, SEM, EDX, and subsequently by FT-IR and Raman spectroscopy. An improvement in the thermal stability of the obtained material compared with the PMMA matrix without filler was evidenced. All performed structural analyzes are recommending the new pink PMMA with 0.4% nano-titania as an as an alternative to the one-piece, single color material for removable dentures processing.
3D Printed Dental Models A comparative analysis
Authors: Tancu Ana Maria Cristina , Pantea Mihaela , Totan Alexandra , Tanase Mihaela , Imre Marina
Published: January 2020

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.
Electromagnetic Pollution of the Environment Due Leakage Radiation from Microwave Ovens
Authors: Panait Diana E. , Jufa Andreea C. , Floroian Laura , Pascu Alina M. , Badea Mihaela , Popa Maria , Macocian Eugen-Victor , Cioca Gabriela , Bungau Simona
Published: January 2020

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.
Dielectric Behavior and Morphostructural Characteristics of Some HDPE Composites / Metal Nanopowders
Authors: Caramitu Alina-Ruxandra , Mitrea Sorina , Marinescu Virgil , Ursan George-Andrei , Aradoaie Mihaela , Lingvay Iosif
Published: January 2020

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.
The Study of Placental Vascularization Using Type AGO II Plastic Substances
Authors: Dumitru Catalin , Petre Izabella , Craina Marius , Moleriu Lavinia Cristina , Suciu Nicolae , Gobjila Carolina , Pop Elena , Sisu Alina , Radu Daniela , Oancea Roxana
Published: January 2020

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.
Neutralization with Simultaneously Separation of Aluminum Ions from Condensate Water through Cellulose Derivatives-Capillary Polypropylene Composite Membranes
Authors: Nafliu Ion Marius , Grosu (Miron) Alexandra Raluca , Al-Ani Hussam Nadum Abdalraheem , Albu Paul Constantin , Gheorghievici Gavril , Craciun Mihaela Emanuela
Published: January 2020

Environmental problems that arise from acidic water containing aluminum generated from condensing thermal power plants can be suitably solved using membrane processes. In this paper, simultaneous neutralization with aluminum ion separation, from acidic waters containing aluminum traces, through permeation with polypropylene with inclusions of cellulose derivatives (PP / CellD)capillary composite membranes is approached. Cellulose derivatives considered are: acetylcellulose, carboxymethylcellulose, 2-hydroxyethyl cellulose, methyl 2 hydroxyethyl cellulose. The optimum working parameters for the best performance of composite membrane based on carboxymethylcellulose were determined: operating time and pH of the receiving phase. Simultaneously with the quantitative removal of the aluminum ions, it is obtained an almost neutral pH purified water, compatible with the natural waters in which it can be dispersed.
Formulation and Characterization of Polyurethane Microstructures with Propolis Extract
Authors: Duca Alexandra , Borcan Florin , Muntean Danina M. , Alexa Ersilia C. , Soica Codruta M.
Published: January 2020

Propolis is a natural apicultural product derived from plant resins with impressive health benefits. Its major biologically active substances are barely soluble in water, but this could be increased by proper formulations.The aim of the present study was to obtain a transmembrane delivery system based on polyurethane microstructures for eight propolis samples collected from different regions of Western Romania and to characterize them by differential scanning calorimetry (DSC); the assessed parameters were the particle size, the polydispersity index and their clustering tendency. Polyurethane polymers based on isophorone-diisocyanate and polyethylene glycol 200/ethylene glycol were chosen as carriers for the propolis extract. A perfect inclusion of propolis inside the structures was observed for half of the samples. Particle size ranged between 504 and 621 nm and was confirmed by the low stability against aggregation (Zeta potential: 16.3-19.8 mV). The polydispersity index was between 0.4 and 0.7.
Blade Polymeric Material Study of a Cross-Flow Water Turbine Runner
Authors: Stroita Daniel Catalin , Manea Adriana Sida , Cernescu Anghel
Published: January 2020

Although Romania has a consistent hydro energetic potential, till now is valuated just approximate 30 percent of it. On the big rivers there are already installed high power hydro plants, but a lot of small and medium rivers are not valuated energetically. Installing a new high power hydro plant tends to affect the zone, being necessary a lot of changes in the environment. The Cross-Flow hydraulic turbines don�t need very complex hydro settlements, being very suitable for small and medium power hydro plants. Also a quite big potential in the use this type of hydraulic machines is the energy recovery in the water treatment and sewage plants. The turbine�s blades surfaces enters in contact with the pressurized water jet. The water jet creates a hydrodynamic force that tends to stress the blade. Mainly the Cross-flow turbine blades are made from steel. This article presents the hydrodynamic design and the possibility of using new polymeric material Delrin �AF for the Cross-Flow turbine runner blades, together with the stress analysis.
Constructiv and Technological Consideration on the Generation of Gear Made by the DLP 3D-Printed Methode
Authors: Vasilescu Mircea Dorin
Published: January 2020

The aim of the work is conduct to highlight how the technological parameters has influence of 3D printed DLP on the generation of wheel, made from resin type material. In the first part of the paper is presents how to generate in terms of dimensional aspects specific design cylindrical gears, conical and worm gear. Generating elements intended to reduce the cost of manufacturing of these elements. Also are achieve the specific components of this work are put to test with a laboratory test stand which is presented in the paper in the third part of the paper. The tested gears generated by 3D-printed technique made with 3D printed with FDM or DLP technique. After the constructive aspects, proceed to the identification of conserved quantities, which have an impact both in terms of mechanical strength, but his cinematic, in order to achieve a product with kinematic features and good functional domain specific had in mind. The next part is carried out an analysis of the layers are generated using the DLP and FDM method using an optical microscope with magnification up to 500 times, specially adapted in order to achieve both visualization and measurement of specific elements. In the end part, it will highlight the main issues and the specific recommendations made to obtain such constructive mechanical elements.
Imagistic Analysis of Dental Adhesives Loaded with Nanoparticles Used on Teeth Sealing of Pits and Fissures with Resin Based Materials
Authors: Oancea Roxana , Zaharia Cristian , Gabor Alin-Gabriel , Sinescu Cosmin , Mioc Marius , Vaduva Delia Berceanu , Simon Catalin Petru , Socoliuc Vlad , Rominu Mihai , Negrutiu Meda-Lavinia
Published: January 2020

Recent assessments show an increase in the incidence of tooth decay. In addition to prophylactic treatments using fluoride and diet focused on low sugar consumption, application of sealing materials to the teeth surfaces is the best protection against the appearance of dental caries on both temporary and permanent teeth.Tooth sealing applied using conventional method, plus the application of adhesive systems can lead to noticeable results over time.An increased thickness of the adhesive layer may lead to microinfiltration and implicitly to a failure of the dental caries protection therapy.Loading the dental adhesive with magnetic nanoparticles and applying it to the surface of the teeth with the help of a the magnetic field attempts to reduce and uniformize the thickness of the adhesive layer, which can lead to a reduced decrease in the occurrence of dental caries under the sealing materials for pit and fissures on the occlusal surfaces.