Influence of gaseous laser in continuous-wave and pulse regimes on biomaterial characteristics

Aromatic plants and laser beam wavelength in the red range of visible spectra (623.8 nm), most commonly used for treating plant species, were selected. As there is not much information in the references, it is necessary to set a scale with qualitative and partially quantitative evaluations of the results. Specimens of thyme seed (Thymus vulgaris) were selected as aromatic plants for studying the effect of low-power lasers on plant development, and continuous He-Ne laser, with irradiation times in the range of minutes

System for Characterization of Supercapacitors

The hardware and software system, based on LabVIEW package, for electrical investigations of supercapacitors was developed. The system provides standard testing (cyclic voltammetry, constant current charge and discharge, electrochemical impedance spectroscopy, etc.) of supercapacitors in the temperature range of 30 to 100 degrees C and under pressure up to 3 bars. The effectiveness of the system was verified

Microhardness of decorative gold coatings obtained from gold complex based on mercaptotriazole: Comparison with cyanide

The aim of this work was to investigate the effects of current density, temperature, pH and concentration of ethyl-hexilsulfonate additive on the microhardness of electrochemically deposited gold decorative coatings obtained from a conventional cyanide electrolyte and gold complex based on mercaptotriazole. Mechanically and chemically prepared brass samples were first nickeled from acidic electrolyte. Nickel was a substrate deposit, and then decorative gold coatings were deposited from two types of electrolytes at different current densities and temperatures. Decorative gold coatings were deposited from auri-mercaptotrizole at different pH values and from electrolyte with and without the ethylhexilsulfonate additive. The microhardness of the gold coating was measured using the Knoop method. The highest values of microhardness were obtained at a current density of 1 A dm(-2) at room temperature for both electrolytes. The microhardness of the gold coatings from cyanide electrolytes was HK = 740 MPa, and the coatings obtained from auri-mercaptotriazole HK = 660 MPa. This difference is not relevant for decorative purposes. The highest values of microhardness, HK = 660 MPa, were obtained at pH = 9 from the gold complex based on mercaptotriazole without the additive

Electrochemical synthesis and characterization of copper (I) oxide

The quest and need for clean and economical energy sources have increased interest in the development of thin film cells technologies. Electrochemical deposition is an attractive method for synthesis of thin films. It offers the advantages of low synthesis temperature, low cost and high purity. Copper (I) oxide or cuprous oxide is an oxide semiconductor which is used as the anodic material in the form of thin film in lithium batteries and solar cells. The cathodic process of synthesis of cuprous oxide thin film is carried out in a potentiostatic mode from the organic electrolyte. The process parameters are chosen in that way to accomplish maximum difference between the potentials at which Cu2O and CuO are obtained. The electrochemical characterization was carried out by cyclic voltammetry. The electrodeposition techniques are particularly well suited for the deposition of single elements but it is also possible to carry out simultaneous depositions of several elements and syntheses of well-defined alternating layers of metals and oxides with thicknesses down to a few nm. Nanomaterials exhibit novel physical properties and play an important role in fundamental research. In addition, cuprous oxide is commonly used as a pigment, a fungicide, and an antifouling agent for marine paints. It is insoluble in water and organic solvents. This work presents the examinations of the influence of bath, temperature, pH and current density on the characteristics of electrochemically synthesized cuprous oxide. In the 'classic' process of synthesis, which is carried out under galvanostatic conditions on the anode, the grain size of the powder decreases with the increase in current density while the grain colour becomes lighter. The best commercial quality of the Cu2O (grain size, colour, content of choride) was obtained at the temperature of 80°C, concentration of NaCl of 3 mol/dm3 and current density of 400 A/m2

The influence of novel organic gold complex on photoresist layers of printed circuit boards

The goal of this paper was to study the influence of organic gold complex based on mercaptotriazole on photoresist layers used in manufacturing of printed circuit boards (PCBs). Investigations were performed by immersion the previously prepared boards in electrolytes with different pH values (pH=2, 4, 7, 9 and 12) at gold concentration of 2.5 g/dm3 and in gold complexes with different gold concentrations (1.5; 2.0; 2.5; 3.0 and 3.5 g/dm(3)) at pH value of pH=9. Investigations showed that photoresist layers on boards are the most resistant at optimal operating conditions, pH=9 and concentration of gold of 2.5 g/dm(3)

Effect of Al[2]O[3] particles modification on the thermal and mechanical properties of the acrylate based composites

Aluminijum oksid (Al2O3) je keramički materijal koji ima izuzetna mehanička, fizička i hemijska svojstva. Zbog svojih izuzetnih hemijskih svojstava, aluminijum oksid se koristi u kompozitima kao ojačanje i kao materijali za primenu u visokim temperaturama. U kompozitnim materijalima od posebnog interesa su različite strukture aluminijum oksida koje se mogu dobiti termičkom obradom. Cilj ovog rada bio je da se napravi kompozitni materijal sa matricom od PMMA itakonatnog kopolimera i da se ispitaju termička svojstva, u zavisnosti od dodavanja različitih punioca sa modifikacijom površine. Modul elastičnosti i čvrstoća PMMA se smanjuju dodavanjem itakonata u matricu. Čestice na bazi aluminijum oksida sa površinom modifikovanom sa organosilanom – 3-aminopropil-trimetoksilanom (AM) i u drugom stupnju sa metil estrima masnih kiselina lanenog ulja (biodizel-BD) korišćene su kao ojačanja. Čestice sa površinskom modifikacijom uspostavljaju bolju vezu sa polimernom matricom putem kovalentnih i vodoničnih veza i dipol-dipol interakcija. Efikasnim dispergovanjem čestica u matrici se postiže i poboljšan prenos opterećenja kroz matricu koji je praćem putem termovizijske kamere. Termogrami tokom testa na zatezanje ukazuju na razlike u temperaturama koje se javljaju u zoni loma kompozitnih materijala. Temperatura u zoni loma je u uskoj vezi sa efikasnošću prenosa opterećenja i temperaturne provodljivosti samog materijala. Mehanička svojstva materijala se poboljšavaju dodavanjem neorganskih čestica na bazi alminijum oksida sa aktiviranom površinom i na taj način stvoriti novi kompozitni materijal sa poboljšanjim mehaničkim i termičkim svojstava.Aluminum oxide (Al2O3) is a ceramic material that has exceptional mechanical, physical and chemical properties. Due to its extraordinary chemical properties, aluminum oxide is used in composites as reinforcement and as material in high temperature applications. In composite materials of particular interest are different structures of aluminum oxide, which can be obtained by thermal treatment. The aim of this article was to make a composite material with a matrix made from PMMA itaconate copolymer and to examine the thermal properties, depending on the addition of various fillers with surface modification. Modulus of elasticity and the strengths of PMMA are in decrease by adding the itaconate to the matrix. Aluminum oxide based particles were used as reinforcement with a modified organosilane-3-aminopropyl-trimethoxylane (AM) surface and in the second stage with fatty acid fatty acid methyl esters (biodiesel-BD). Surface modification particles establish a better bond with the polymer matrix through covalent and hydrogen bonds and dipol-dipole interactions. Efficient dispersion of particles in the matrix also improves the transmission of the load through the matrix, which is followed by a thermionic camera. Thermograms during tensile test indicate differences in temperatures occurring in the fracture zone of composite materials. The temperature in the fracture zone is closely related to the efficiency of the load transfer and the temperature conductivity of the material itself. The mechanical properties of the material are improved by adding inorganic particles based on the activated surface of aluminum oxide, thereby creating a new composite material with improved mechanical and thermal properties.7. Međunarodna konferencija o obnovljivim izvorima električne energije, Beograd, 17-18. oktobar 201

Electrochemical Behavior of Supercapacitor Electrodes Based on Activated Carbon and Fly Ash

The possibility of applying fly ash from power plants as a binder in supercapacitor electrodes based on activated carbon was investigated in this research. Based on the mechanical and electrical properties of the electrodes, the optimal ratio between fly ash and AC was determined. Supercapacitor electrodes were prepared in two ways: by pressing and by laser solidification. The preparation method significantly affected physical properties of the electrodes as well as the electrochemical behavior in supercapacitor setup. The electrodes were electrochemically tested by galvanostatic and potentiostatic methods and cyclic voltammetry. In order to improve the estimation of supercapacitor parameters, mathematical model that perfectly describes the behavior of investigated electrodes in aqueous solution of sodium nitrate was developed. The best results were obtained with laser-solidified electrode in 1M aqueous solution of NaNO3. Specific capacitance of 105 F/g, serial resistance of 0.57 Omega and self-discharge resistance of 95 Omega were achieved. Stability at high number of cycles proved to be very good. After 2000 cycles of CV at scan rate of 100 mV/s, specific capacitance fell by only 4.6 %