Effects of process stages on Turkish delight/lokum microbiological quality

The sources of microbiological contamination at the lokum production lines of two local confectionaries were determined. Surface samples from the production lines were evaluated by standard and ATP bioluminescence methods. Microbial loads of raw materials were also determined. The trays and cutting knives were found to be the primary contamination sources, and personnel hands were found to be the secondary contamination sources, while all of them were found to be the secondary sources when the standard swab method was applied. Raw materials were not sources of contamination, because of their microbiological loads and the following high‐temperature cooking stages. The microbial loads of lokum also were not high, due to product contents and the processes applied to lokum. There is a need for further studies related to the effects of process steps on the physical and the chemical quality of lokum. Training for workers in food safety at the confectionaries is also needed.     

The effects on the properties of PET bottles of changes to bottle‐base geometry

Poly(ethylene terephthalate) (PET) bottles are commonly used for packaging of carbonated beverages. Stress cracking in the petaloid‐shaped base of the filled bottle has been costly to the beverage industry. This study compares the performance of a standard bottle and a bottle with a base geometry optimized against environmental stress cracking (ESC). The crystallinity of the bottle base is evaluated across the base diameter for both bottles. Moreover, to explain the mechanism of the crack formation and propagation, the cracks in the bottle base are investigated through environmental scanning electron microscopy (ESEM) and optical microscopy. Top‐load strength, burst strength, and thermal stability are also reported. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Effect of elevated temperature on the mechanical properties of concrete produced with finely ground pumice and silica fume

This study investigated the effect of elevated temperature on the mechanical and physical properties of concrete specimens obtained by substituting cement with finely ground pumice (FGP) at proportions of 5%, 10%, 15% and 20% by weight. To determine the effect of silica fume (SF) additive on the mechanical and physical properties of concrete containing FGP, SF has been added to all series except for the control specimen, which contained 10% cement by weight instead. The specimens were heated in an electric furnace up to 400, 600 and 800 °C and kept at these temperatures for one hour. After the specimens were cooled in the furnace, ultrasonic pulse velocity (UPV), compressive strength and weight loss values were determined. The results demonstrated that adding the mineral admixtures to concrete decreased both unit weight and compressive strength. Additionally, elevating the temperature above 600 °C affected the compressive strength such that the weight loss of concrete was more pronounced for concrete mixtures containing both FGP and SF. These results were also supported by scanning electron microscope (SEM) studies.     

Design and analysis of minkowski reflectarray antenna using 3‐D CST microwave studio‐based neural network model with particle swarm optimization

This article presents a systematic analysis and design of the X‐band Minkowski reflectarray antenna (RA) by using the 3‐D Computer Simulation Technology Microwave Studio (CST MWS)‐based multilayer perceptron neural network (MLP NN) model of a unit element. This MLP NN model is utilized efficiently as a fast and accurate model within a particle swarm optimization procedure to determine the calibration phasing characteristic belonging to the resultant optimum patch geometry and substrate. In design stage, the MLP NN analysis model is reversed to determine the variable‐size of each reflectarray element to meet the necessary phase delay with the adaptive iterative step. In the final stage, the optimum Minkowski RA consisting of the variable‐size Minkowski patches interspaced by 0.5 wavelength at the frequency of 11 GHz on the Taconic RF‐35 with ε_r = 3.54, tan δ = 0.0018 and the optimum thickness (h_opt) are analyzed using the 3D CST MWS and compared with the counterpart square and parabolic reflectors. Compared with the counterpart RA with square element and the parabolic reflector, this optimized Minkowski RA is resulted to be capable of providing higher realized gain and lower sidelobe level (SLL). Furthermore, the effect of feed movement along the focal length on the gain‐bandwidth and radiation pattern is also worked out and demonstrated. It is concluded that this method can also be applied as a robust method for the design and analysis of a RA built by arbitrarily shaped patches. © 2013 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2013.     

Geological Setting and the Validity of the Petroleum System Logic in the Taurus Belt of Turkey

The Taurus Belt region is located in the southern part of Turkey and includes the Tauridia highlands, the Autochthonous Taurus Units and the Allochthonous Units in the southern and northern flank of the Tauridia, respectively, and the Gondwanian Units in the southern part of the entire area. The total thickness of Palaeozoic to Cenozoic sediments ranges from 2,500 m (for the Allochthonous Units) to 10,700 m (for the Autochthonous Taurus Units). All Taurus units display many characteristics of a carbonate platform. Previous studies in the Taurus region indicate that the Paleozoic successions in the eastern and central parts of that region include some intervals of potential petroleum source rocks. Some hydrocarbon indications were found in the Akseki, Guzelsu, and Ucyildiz areas.     

Jc enhancement and flux pinning of Se substituted YBCO compound

Y_2/3 Se_1/3Ba₂Cu₃O_x compound was fabricated by using solid state fabrication technique. Optimum heat treatments conditions for Y_0.77Se_0.33Ba₂Cu₃O_x were investigated. It was determined that the XRD results of these samples were similar to Y-123 phase with some impurities. Magnetization dependence of applied magnetic fields was measured in the range of 0–9 T at 10–50 K. The symmetric and asymmetric M–H loops were obtained for the samples. Magnetization loops obtained from measurements were successfully described by the extended Valkov–Khrustalev model. The temperature and applied magnetic field dependencies of magnetization of sample were estimated and critical current density of samples was calculated by Bean model and pinning force of samples was calculated by using Lorentz force. It is found from critical current density values that Se additions were acted as a pinning center which increased critical current density.     

SOURCE ROCK POTENTIAL AND ORGANIC GEOCHEMISTRY OF CENOMANIAN-TURONIAN BLACK SHALES,WESTERN TAURUS,SW TURKEY

The depositional environment and hydrocarbon source rock potential of Cenomanian-Turonian black shales of the Dereköy and Ballik Formations in SW Turkey were investigated by organic geochemical methods. In detail, 33 samples from three section of the Dereköy Formation, and 15 samples from one section of the Ballik Formation were analysed for elemental (TOC, Rock -Eval pyrolysis), C₁₅₊-lipid and biomarker compositions. Based on maximum pyrolysis degradation temperatures of not more than 420°C, all the shale samples are classified as immature, corresponding to a vitrinite reflectance of less than 0.45% R_r and a lignite to sub-bituminous coal stage. This is confirmed by relatively high isoprenoid to n-alkane ratios as well as by high biomarker contents. According to this maturity stage, and both total organic carbon contents of 6–41% and hydrogen indices of 255–708 mg HC/g TOC, the Cenomanian-Turonian black shales exhibit fair to excellent source rock potential with mixed Type II and Type I kerogen. Relatively high isoprenoid to n-alkane ratios may indicate at least partial (bio-) degradation/evaporation/waterwashing and selective modification of the lipid composition due to the nature of the outcrop. However, very similar unimodal n-alkane distributions in the gas chromatograms of four selected shale samples, with a predominance in the C₁₆ to C₁₇ region, clearly point to a significant contribution of algal and/or bacterial type organic matter with low terrigenous organic input. C₂₇, C₂₈ and C₂₉ steranes in shales from both formations have similar distributions (C₂₉>C₂₇>C₂₈). High C₃₁ R homohopane / C₃₀ hopane ratios indicate a marine depositional environment. This is confirmed by the presence of gammacerane in all the black shales investigated which in general indicates salinity. Pregnanes in one sample (BA-6) may point to hypersaline conditions.     

Vortex pinning and magnetic peak effect in Eu(Eu,Ba)2.125Cu3Ox

Eu–Ba–Cu–O composition was synthesized by solid state reaction technique. To determine optimum growth temperature, heat treatment was examined on the material at 880–1,100 °C. Microstructural evolution, phase formation and elemental distribution depending on heat treatments were examined by using X-ray diffraction, scanning electron microscope, energy dispersive X-ray spectroscope analysis. Optimum fabrication conditions were determined as 1,020 °C for 24 h under oxygen atmosphere and detailed characterization of corresponding compound was performed. The magnetization hysteresis loops are expounded to be the product of superconducting Eu-123 grains and magnetic Eu²⁺ ions. The peak effect on the magnetization curves was described by the extended critical state model. Scaling of the pinning force was found such that the peak position is proportional to the irreversibility field H _irr and the maximum pinning force is proportional to H _irr ² .     

Formation and Organization of Amino Terminated Self-assembled Layers on Si(001) Surface

We have investigated the effects of dipping time, solution concentration and solvent type on the formation of self-assembled monolayers with aminosiloxane molecules (i.e., N-(3 trimethoxysilylpropyl)diethylenetriamine (TPDA)) on the Si(001) surface. Studies performed with an ellipsometer showed that monolayers with a thickness of about 1.2 nm were formed when the dipping time is about 2 h, while multilayer were observed for longer time periods. The effect of the TPDA concentration on the thickness of the deposited layer was not very profound, however, the contact angle data exhibit importance of concentration on the surface coverage. The type of the solvent used in the formation of the monolayers was found an important parameter. Monolayers were formed with solvent having larger dielectric constants. Relatively thick multilayer was observed when benzene was used as the solvent, due to its quite low dielectric constant (hydrophobicity).     

Effects of concentration and temperature on the coupled heat and mass transport in liquid mixtures

Using published experimental data on the thermal conductivity, mutual diffusivity, and heats of transport, the degree of coupling between heat and mass flows has been calculated for binary and ternary nonideal liquid mixtures. The binary mixtures consist of two types: the first is six systems of six-to-eight-carbon straight and branched chain alkanes in chloroform and in carbon tetrachloride; and the second is mixtures of carbon tetrachloride with benzene, toluene, 2-propanone, n-hexane, and n-octane. The ternary mixture considered is toluene-chlorobenzene-bromobenzene. The published data are available at 25°C, 30°C and 35°C and ambient pressure. Using the linear nonequilibrium thermodynamics (LNET) and the dissipation-phenomenological equation (DPE) approach, the effects of concentration, temperature, molecular weight, chain-length, solute, solvent, and branching on the degree of coupling are examined. The extent of coupling and the thermal diffusion ratio are expressed in terms of the transport coefficients to obtain a better understanding of the interactions between heat and mass flows in liquid mixtures. It is found that the composition of the heavy component bromobenzene changes the direction and magnitude of the two-flow coupling in the ternary mixture.