Aromatic products of 340 °C supercritical-toluene extraction of two Turkish lignites: an n.m.r. study

Fractions of Elbistan and Seyitomer (Turkish) lignites, extracted with supercritical toluene at 340 °C and 8 MPa, have been separated by solvent extraction and silica-gel chromatography. Analyses by n.m.r. and i.r. spectroscopies and other methods have been combined in structural-analysis schemes to yield information about the average molecule in aromatic extracts. Carbon aromaticities, f_a, derived from 22.63 MHz ¹H-decoupled pulse Fourier-transform (PFT) ¹³C-n.m.r. are more widely spread for Elbistan (0.34–0.56) than for Seyitomer (0.40–0.43), and are lower than for supercritical-gas (SCG) products from bituminous coals. ¹³C-n.m.r. also reveals the presence of aromatic ether-O in polar fractions. Narrow aromatic signals in 100 MHz ¹H-n.m.r. spectra suggest the presence of single-aromatic-ring average structures. In the hexane-soluble aromatics, 27% (Elbistan) and 29% (Seyitomer) of the available sites are substituted by alkyI groups, some of which are at least eight carbon atoms long; the hexane-soluble polar and asphaltene/asphaltol fractions contain fewer such groups.     

Innovative potential of 3D software applications in fashion and textile design

Advanced cloth simulation plug-in tools are increasingly being used by designers in movies, television, advertising and computer games, to take the strain out of creating and simulating realistic cloth effects for dressing virtual characters. This paper describes experiments into designing textiles and clothing using 3D graphics software and a digital cloth dynamics plug-in, which are an integral part of PhD research in progress. The methods used in testing the 3D software and the cloth dynamics plug-in illustrate the experiences of a designer/learner. The results identify designer/learner needs and expectations for the further educational development of the research and use of cloth simulation tools in textiles/fashion design in the near future.     

Query Processing Techniques for Multimedia Presentations

A multimedia presentation is a synchronized, and possibly interactive, delivery of multimedia data to users. We expect that, in the future, multimedia presentations will be stored into and queried from multimedia databases. In an earlier work, we have designed a graphical query language, called GVISUAL, that allows users to query multimedia presentations based on content information. In this paper, we discuss GVISUAL query processing techniques for multimedia presentations. More specifically, we discuss the translation of GVISUAL queries into an operator-based language, called O-Algebra, with three new operators, and efficient implementations of the new O-Algebra operators using a coding system called nodecodes.     

Experimental investigation of porous bearings under different lubricant and lubricating conditions

The performance of porous bearing under different lubricants and lubricating conditions was experimentally investigated in this study. In order to carry out the experiments, a new test rig was designed to determine the tribological properties of based sintered bronze journal bearings that were manufactured by powder metallurgy (P/M) techniques. To determine the effects of lubricating conditions with and without oil supplement (OS) on the tribological characteristics of these bearings under static loading and periodic loadings, some experiments were carried out using different lubricants. In the tests, pure base oil (SAE 20W50), two fully formulated commercial engine oils (SAE20W50) and lubricating oils with commercial additive concentration ratio of3% were used. The worn surfaces of test bearings were examined using optical microscopy. Experimental results showed that the change in friction coefficient was more stable and in smaller magnitude under static loading than that of periodic loading. In addition, the friction coefficient and the wear rate conducted with base oil resulted in higher values than those of fully formulated oils with and without OS lubricating conditions. The experimental results obtained in this study indicated that the correct selection of lubricant and suitable running conditions were very important on the tribological characteristics of porous bearings.     

Effect of Bicarbonate Salts and Sequential Using of Frying Oil on Acrylamide and 5-Hydroxymethylfurfural Contents in Coated Fried Chicken Meat

In this research, the effect of different bicarbonate salts (sodium and ammonium) and their doses (0, 1, 2, and 3 g/100 g raw material) in the coating batter formula use and the sequential use of frying oil (1st, 2nd, 3rd, and 4th) on 5-hydroxymethylfurfural and acrylamide contents in coated fried chicken meat. The addition of sodium bicarbonate was efficient for reducing acrylamide content, but it increased browning and 5-hydroxymethylfurfural content compared to the control. When increasing the doses of sodium and ammonium bicarbonate from 1 to 3 g/100 g of raw material, the acrylamide content of samples did not change significantly, although adding sodium bicarbonate significantly reduced the acrylamide content as a control. These research results showed that using about 1 g/100 g raw material sodium bicarbonate rather than ammonium bicarbonate and as little frying oil as possible use during the production of coated and fried meat results in lower contents of 5-hydroxymethylfurfural and acrylamide.     

Pyrolysis of giant mullein (Verbascum thapsus L.) in a fixed-bed reactor: Effects of pyrolysis parameters on product yields and character

Slow pyrolysis of giant mullein (Verbascum thapsus L.) stalks have been carried out in a fixed-bed tubular reactor with (Al₂O₃, ZnO) and without catalyst at four different temperatures between 400 to 550°C with a constant heating rate of 50°C/min and with a constant sweeping gas (N₂) flow rate of 100 cm³/min. The amounts of bio-char, bio-oil, and gas produced were calculated and the compositions of the obtained bio-oils were determined by gas chromatography-mass spectrometry. The effects of pyrolysis parameters, such as temperature and catalyst, on the product yields were investigated. The results show that both temperature and catalyst have significant effects on the conversion of Verbascum thapsus L. into solid, liquid, and gaseous products. The highest liquid yield of 40.43% by weight including the aqeous phase was obtained with 10% zinc oxide catalyst at 500°C temperature. Sixty-seven different products were identified by gas chromatography-mass spectrometry in the bio-oils obtained at 500°C temperature.     

Novel mixed ligand complexes of Co(II), Ni(II), Cu(II), and Zn(II) with 1,10-phenanthroline and acesulfame. Synthesis,structural analysis and hydrogen adsorption study

Four novel metal organic framework (MOF) structures containing acesulfame (ace) and 1,10-phenanthroline (phen) ligands of Co²⁺, Ni²⁺, Cu²⁺ and Zn²⁺ metal cations were synthesized. The crystal structure analysis of three compounds (1, 2, and 3) was also performed. The structural formula for complex 4 is proposed based on spectroscopic and thermal analysis data. It has been determined that structures 1, 2, and 4 are in a distorted octahedral geometry. It has been suggested that the charge balance of the coordination sphere with 2+ is provided by two monoanionic ace ligands located outside the coordination sphere as counter-ion. In structure 3, there are two Cu^II metal cations, two phen ligands coordinated as bidentate to each metal cation and ace ligand that provides monoanionic-monodentate coordination. The Cu²⁺ cation has distorted bipyramidal geometry. The maximum hydrogen gas adsorption has been found 1.4575 mL/g (0.046 wt%) for the Ni complex.     

Multi-objective process optimization for micro-end milling of Ti-6Al-4V titanium alloy

Micro-end milling is one of the promising methods for rapid fabrication of features with 3D complex shapes. However, controlling the micro-end milling process to obtain the desired results is much harder compared to that of macro-end milling due to the size effect and uncontrollable factors. The problem is much pronounced when workpiece material is a difficult-to-process material such as titanium-based alloys which are widely used as material of choice for aircraft structures, turbine blades, and medical implants. In order to find the optimal process parameters which minimize the surface roughness and burr formation, experiments were conducted and models obtained with statistically based methods utilized in multi-objective particle swarm optimization to identify optimum process parameters. The results show that the average surface roughness can be minimized while burr formation is reduced concurrently.     

Ion Chromatographic Determination of Free Cyanide in Different Classes of Bottled Natural Mineral Water Consumed in Turkey

An ion chromatographic method for the quantitative determination of free cyanide in bottled natural mineral waters were measured in terms of selectivity, linearity, the limit of detection, limit of quantification, repeatability, precision, and accuracy. Chromatographic separation of free cyanide ions was accomplished with an anion-exchange column and detected by pulsed amperometric detection with a silver working electrode. The method was found to be selective, linear (r² = 0.999) at a concentration range of 0.5 to 134 μg L^?1, precise, and accurate. Recovery values of free cyanide in all classes of natural mineral water varied from 65.9 ± 1.6 to 95.2 ± 0.7 at different spiking levels (5–70 μg L^?1). Parameters (total dissolved solids, mineral interferences, and added sodium hydroxide) affecting the recovery values were studied in this project. The limit of detection and limit of quantification were found to be 0.295 and 0.983 μg L^?1, respectively. The proposed method was applied to 27 different brands of commercially available bottled natural mineral water products sold in Turkish markets. These natural mineral waters were classified as: (i) very low mineral concentration, (ii) low mineral concentration, (iii) intermediate mineral concentration, and (iv) high mineral concentration based on their total dissolved solids contents according to European Union Directive (Directive 80/777/EEC). Levels of free cyanide residues in the samples ranged from > limit of detection to 6.12 μg L^?1. The highest average concentration of free cyanide residues was found in the class of “high mineral concentration waters.” However, the determined free cyanide values in all of the tested natural mineral water samples were found to be within the limits of European Union legislation.     

Biodiversity and technological properties of yeasts from Turkish sourdough

Food Science and Biotechnology - In this study, yeasts were isolated and characterized from twelve traditional sourdough samples which belongs to Black Sea and Aegean regions of Turkey. Twenty six...