An investigation on wear behavior of UHMWPE/carbide composites at elevated temperatures

Ultra-high molecular weight polyethylene (UHMWPE) is extensively used in frictional applications due to its advanced wear resistance. This advanced polymer is reinforced with hard particulate fillers for further developments against wear conditions. Since elevated temperatures prevail in the service conditions, wear behavior of UHMWPE composites is an important issue for the engineering applications. In the present work, UHMWPE-based composites including silicon carbide (SiC) fillers were fabricated in a compression molding chamber. In the specimen preparation stage, molding pressure, filler amount, and filler particle size were varied to investigate the influence of these variables. Upon deciding the optimum parameters from the wear tests conducted at room temperature, the wear experiments were repeated for the optimum specimen at elevated temperatures, such as 40 and 60°C. According to the results, the wear behavior of the SiC/UHMWPE composites is heavily changed by the effect of elevated temperature. Adhesive effect is pronounced at elevated temperatures while the wear characteristics possess the abrasive effect in the sliding path. In addition, the composites exhibit an accelerated material loss as temperature increases during the frictional system.     

Physical and mechanical properties of Gokceada: Imbros (NE Aegean Sea) Island andesites

The physical and mechanical properties of the andesite forming much of the island of Gökçeada (Imbros), Turkey, were investigated using 54 mm samples cores from 12 blocks obtained from a quarry. The results were evaluated using regression analysis and good empirical relationships were obtained.     

Recent Advances in the Modelling of Solid Flows in the Blast Furnace

The solid flow inside a blast furnace is modelled using a standalone finite element program and a constitutive equation called hypo‐plastic, in order to better simulate the granular material behaviour. The parameters of this constitutive equation are calibrated using data obtained from simple soil mechanics tests on coke and sinter materials, such as triaxial and oedometric devices. Steady velocity, stress and void fraction fields are obtained after several iterations of the code. Knowledge of the solids velocity field makes it possible to determine the dead man profile, as well as its renewal kinetics. Burden trajectories and time lines are also computed. Knowledge of the stress field makes it possible to compute pressures acting on the burden as well as on the walls. Finally, knowledge of void fraction field makes it possible to determine gas paths. The solid flow model was validated on 2D and 3D small‐scale cold blast furnaces, but the simulations never required any tuning parameter. This code is in fact an invaluable tool to determine the effect of blast furnace profile on solid flow conditions, and reciprocally.     

Production of aflatoxins in sausage,salami, sucuk and kavurma

Forty nine meat product samples were examined for the fungal genera. Penicillium sp. was detected in 74.8% of samples. No sample contained Aspergillus parasiticus or Aspergillus flavus. Production of aflatoxins in sausage, salami, sucuk and kavurma by A. parasiticus and A. flavus was studied at different temperatures. A. parasiticus and A. flavus produced no aflatoxins on meat products samples at 15°C. Sucuk was a poor substrate for A. parasiticus and A. flavus at 25°C. Sausage, salami and kavurma were favorable substrates for aflatoxin production by A. parasiticus at 25°C.     

Biosorption of lanthanum and cerium from aqueous solutions by Platanus orientalis leaf powder

The biosorption of lanthanum and cerium by leaves powder of Platanus orientalis was separately determined at varying experimental conditions using a batch technique. The effects of initial pH, contact time, initial metal ion concentration and temperature were investigated. The Langmuir and Freundlich isotherms were applied to represent the adsorption process. Langmuir isotherm fits the experimental data quite well. The Langmuir monolayer capacity of the sorbent is 28.65mg g^− 1 and 32.05mg g^− 1 for La and Ce(III), respectively. Thermodynamic parameters such as standard enthalpy (ΔH°), entropy (ΔS°) and free energy (ΔG°) were calculated from the slope and intercept of the plots of lnK_d versus 1/T. The results indicated that sorption was endothermic and spontaneous in nature. The work reveals that powdered leaf of Platanus orientalis is a good choice as a biosorbent for the recovery of lanthanum and cerium from aqueous solution.     

Rheological and Sensory Properties of Spray Dried Pekmez Mixtures with Wheat Starch-Gum

Pekmez, known also as grape molasses, was spray dried in the laboratory-type pilot drying unit to obtain pekmez powder. The flow characteristics of diluted pekmez powder (DPP), wheat starch (WS), and some hydrocolloids (locust bean gum, LBG; gum tragacanth, GT, and guar gum, GG) systems in double- or triple-mixed combinations were studied. The empirical power law model fitted the apparent viscosity-rotational speed data. DPP-gum and WS-gum mixed solutions exhibited a shear-thinning behaviour at 21°C with flow behaviour index (n) values of 0.88 ≤ n ≤ 0.94 and 0.17 ≤ n ≤ 0.32, respectively. WS-gum mixed solutions showed high shear-thinning behaviour with the highest consistency index (k = 49.93–214.24 Pa sⁿ). However, DPP-WS and DPP-WS-gum mixed solutions at the same temperature exhibited the shear-thickening behaviour with flow behaviour index (n) values of 1.02 ≤ n ≤ 1.07.     

A flexible and scalable audio information retrieval system for mixed‐type audio signals

The content‐based classification and retrieval of real‐world audio clips is one of the challenging tasks in multimedia information retrieval. Although the problem has been well studied in the last two decades, most of the current retrieval systems cannot provide flexible querying of audio clips due to the mixed‐type form (e.g., speech over music and speech over environmental sound) of audio information in real world. We present here a complete, scalable, and extensible content‐based classification and retrieval system for mixed‐type audio clips. The system gives users an opportunity for flexible querying of audio data semantically by providing four alternative ways, namely, querying by mixed‐type audio classes, querying by domain‐based fuzzy classes, querying by temporal information and temporal relationships, and querying by example (QBE). In order to reduce the retrieval time, a hash‐based indexing technique is introduced. Two kinds of experiments were conducted on the audio tracks of the TRECVID news broadcasts to evaluate the performance of the proposed system. The results obtained from our experiments demonstrate that the Audio Spectrum Flatness feature in MPEG‐7 standard performs better in music audio samples compared to other kinds of audio samples and the system is robust under different conditions. © 2011 Wiley Periodicals, Inc.     

An intelligent multimedia information system for multimodal content extraction and querying

Multimedia Tools and Applications - This paper introduces an intelligent multimedia information system, which exploits machine learning and database technologies. The system extracts semantic...