A class of intensively studied materials with application in areas where complex structures with precise geometry are needed (i.e. electronics), are the self-organized nanomaterials. Polymer, metallic and composite self-organized nanomaterials have been in researchers’ attention the last decades. They are not only appealing scientifically, by revealing the intrinsic atomic and molecular interactions that might be difficult to detect otherwise but may also hold the key for the development of novel functional structures and devices. The different mechanisms and forces involved in the self-formation of organized nanostructures are discussed in the present manuscript. Further on, key formation fundamentals involved in the fabrication of self-organized nanostructures are described. Between the known manufacturing methods, the electrochemical synthesis is considered extremely simple and cost effective. On the other hand, it involves a wide range of synthesis parameters (e.g. voltage, electrolyte type, temperature, experiment duration, pH etc.) that may lead to the formation of ingenious structures with complex geometries at different length scales. Finally, some representative scientific investigations are mentioned together with applications of self-organized nanomaterials in different engineering and life areas.
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The experimental results obtained by studying the influence of different types of fibers on the mechanical properties of fly ash polymer concrete are presented in the paper. The general demand of using wastes found applicability in building material industry because some of them are beneficial in improving concrete properties. The waste additions type fly ash and fibers were incorporated in polymer concrete. The study focused on fibers type glass, polyester, metallic and cellulose. The mechanical properties such as compressive strength, flexural strength and split tensile strength were investigated having in view the type, dosage and length of fibers. The results show that fibers improved mechanical properties in comparison with that of polymer concrete without fibers, the test results being differently influenced by the factors which were considered.
Composites made from metallic fillers embedded in polymer matrix have good shielding properties as electrical point of view and tribology properties from mechanical point of view. These properties depend on amounts, shapes, sizes, and combinations of fillers and matrix. This paper proposes an electromagnetic method for determination of metallic fillers concentration in composite materials from metallic fillers embedded in polyester matrix. The bulk resistivity and dielectric permittivity were measured but these measurements are less influenced by the fillers concentration. The amplitude measurement of e.m.f induced in the reception coil of the focalized electromagnetic transducer and their averaging for the scanning of a relative large zone of the composite has proven to be an efficient method. The average amplitude linearly decreases with the increasing of fillers concentration, and has different values for Cu and AISI 316 fillers.
The classical method of teaching human anatomy to students is based on the dissection of human cadavers. Nowadays, there are many ethical controversy regarding the use of human cadavers during anatomy courses. In our study we tried to get undergraduate students’ opinion about some different techniques of teaching human anatomy, including the utility of plastic models. We introduced in this study 163 students in the first year of their study at the Faculty of General Medicine from the University of Medicine and Pharmacy, Tirgu Mures. The respondents were asked to fill in a 12-item anonymous questionnaire. Based on the answers provided in the questionnaires we divided the 163 respondents into 2 groups: group A comprising 113 (69.32%) respondents who found that the best method of teaching anatomy is cadaver dissection and group B comprising 50 (30.67%) respondents who found that the best method of teaching is not cadaver dissection. Thus, 20 (12.26%) respondents considered that the best method of teaching anatomy is the use of previously dissected and preserved preparations, 4 (2.45%) indicated the use of plastic models as the best method, 24 (14.72%) would prefer 3D techniques of image reconstruction and 2 (1.22%) respondents found that the best method of teaching anatomy is by Microsoft Office PowerPoint presentations. Even though there are still controversial opinions regarding the use of cadaver dissection in teaching and learning human anatomy, especially ethical and psychological ones, cadaver dissection remains the best method of teaching anatomy to undergraduate students in medical schools.
The acoustic comfort includes the protection against noise and it is closely related to the sound absorption concept. This paper presents an experimental study on sound absorption coefficients, for some composite materials: waste materials (rubber crumbs, textile, flax fibers) mixed with rigid polyurethane foam as binder. The composite materials were characterized both acoustically (sound absorption coefficient) and also in terms of heat transfer (thermal conductivity). The acoustic absorption coefficient was determined using the impedance tube and the influence of structure of these materials on the sound absorbing properties was analyzed. The experimental results show the sound absorption performances of some composites based on recycled waste materials, thus promoting environmentally friendly solutions.
Because cyancobalamin deficiency is commonly treated with parenteral adminstration, the present study aims to make a comparison between the effectiveness of parenteral vitamin B12 treatment and the effectiveness of local treatment achieved by complete dentures improved by crosslinked polymerization using as template vitamin B12 (cyanocobalamin).
The aim of this study was the development and formulating of a cosmetic product and the assessment of compatibility tests performed on the product, transfered to the cosmetic jar. Sample of cosmetic cream were stored using 50 mL PP (Polypropylene) plastic containers. The developed cosmetic formulation was monitored under accelerated stability studies. Accelerated stability tests were performed over a period of 30 days while maintaining the product at 4, 20 and 40°C. Quality control initial, and after initiating the accelerated stability test was performed for the developed cosmetic formulation.
The developments in the biocompatible materials and additive manufacturing technologies gave birth to new possibilities in reconstructive surgery. In addition to revolutionizing the diagnostic possibilities, the modern medical imaging has led to the development of surgical planning software. Using these state-of-the-art technologies, a new standard of care is rising with the spread of patient specific implants. Our view in studying and using these materials and technologies goes beyond their biocompatibility, focusing on the functional and esthetic impact of these restorations. Our aim is to show their potential benefits and pitfalls presenting a couple of posttraumatic and oncological application possibilities, focusing on the new presurgical planning, choice of materials and manufacturing technologies.
The aim of the study was to evaluate the influence of different techniques of finishing and polishing as well as the use of sealants on the surface condition of some composite resins used in the dental office. 80 specimens of composite materials (Nanoceramic, Nanocomposit and Nanohybrid) were made and divided into 3 groups G1-coated composite with sealant lacquer, G2 - finished in 2 stages, and G3 - finished in 3 stages. Roughness (Ra) was determined with the Taylor Hobson Form Talysurf Profiometer. The data was analyzed using one-way ANOVA followed by a multiple comparison t test. Significant differences were found between the groups in terms roughness (p < 0.001). The results showed that Seal – and - Shine (PULPDENT) was capable of reducing surface roughness and provided polished surfaces for all materials.
The research concerns the transmission of electromagnetic waves with a wavelength corresponding to the visible part of the spectrum and part of the ultraviolet and infrared radiation range. Light transmittance through ocular lenses was tested using a UV-Vis spectrophotometer for the wavelength range 250-850 nm. Obtained results encourage reflection on the quality of the spectacle lenses produced. The obtained results do not confirm the assurances of producers about the increase in light transmittance in the range of wavelengths corresponding to the highest sensitivity of the human eye. In addition, lenses having UV protection coatings do not perform their function in a proper way. Eyeglass lenses of various classes were tested, equipped with various refining coatings. The effect of the number of coatings on the transmission of light through the lenses was not observed. Conducting and publishing studies such as those presented in this work may have a significant impact on the improvement of the quality of manufactured eyeglass lenses.