Effects of Some Metals and Chelating Agents on Patulin Degradation by Ozone

The efficiency of ozone treatment for degradation of the mycotoxin patulin in the presence of various metal ions was evaluated in model systems. An initial patulin concentration of 250 μg/L was ozonated and residual ozone concentration was about 0.17±0.01 mg/L at the end of the experiment. Patulin showed a weak resistance to ozone, because up to 98% of this toxin was oxidized in only one minute. Degradation rates in the presence of calcium, aluminum, copper and zinc were almost the same in the absence of these metals. However, degradation of patulin was reduced from 98 to 37% when the concentration of manganese increased from 0 to 3 mg/L. Patulin was almost completely degraded in the absence of iron, while the degradation was only 8.5% in the presence of 0.5 mg/L of iron. These results have revealed that manganese and iron significantly reduce the detoxification of patulin by ozone. Agents such as ethylenediaminetetraacetic acid and sodium polyphosphate effectively chelated iron and increased the degradation rate of patulin. None of the tested agents were able to chelate manganese and to enhance patulin degradation by ozone.     

Implementation of a single-phase matrix converter induction motor drive

This paper presents an implementation of a single-phase matrix converter for a variable speed single-phase induction motor. The paper analyzes the characteristics of a single-phase ac–ac converter drive with particular emphasis on the harmonic content, input voltage utilization and variable speed performance of the motor. Both square and sinusoidal wave modulation signals in PWM generation have been used to demonstrate the effect of the modulating signal on the input voltage utilization and output harmonic content. Simulation and experimental results for an R–L and induction motor loads are presented. Promising results illustrate that a good performance of a single-phase induction motor fed by a matrix converter is achievable.     

Application of gene expression programming in hot metal forming for intelligent manufacturing

Design of the die in hot metal forming operations depends on the required forming load. There are several approaches in the literature for load prediction. Artificial neural networks (ANNs) have been successfully used by a few researches to estimate the forming loads. This paper aims at using the effectiveness of a new evolutionary approach called gene expression programming (GEP) for the estimation of forging load in hot upsetting and hot extrusion processes. Several parameters such as angle (α), L/D ratio (R), friction coefficient (µ), velocity (v) and temperature (T) were used as input parameters. The accuracy of the developed GEP models was also compared with ANN models. This comparison was evidenced by some statistical measurements (R ², RMSE, MAE). The outcomes of the study showed that GEP can be used as an effective tool for representing the complex relationship between the input and output parameters of hot metal forming processes.

     

Characteristics of brick used as aggregate in historic brick-lime mortars and plasters

Mortars and plasters composed of a mixture of brick powder and lime have been used since ancient times due to their hydraulic properties. In this study, raw material compositions, basic physical, mineralogical, microstructural and hydraulic properties of some historic Ottoman Bath brick-lime mortars and plasters were determined by XRD, SEM-EDS, AFM, TGA and chemical analyses. The mineralogical and chemical compositions, microstructures, morphologies and pozzolanicities of the brick powders and fragments used as aggregates in the mortars and plasters were examined to find out the relationship between hydraulic properties of the mortars and the bricks. The characteristics of bricks used in the bath domes were also determined to investigate whether the brick aggregates used in mortar and plasters were prepared from these bricks. The results indicated that the mortars and plasters were hydraulic owing to the presence of crushed brick powders that have good pozzolanicity. The brick powders had high pozzolanicity because they contained high amounts of calcium-poor clay minerals in their raw materials that were fired at low temperatures. On the other hand, bricks used in the domes had poor pozzolanicity with different mineralogical and chemical compositions from bricks used in mortars and plasters. Based on the results of the analysis, it was thought that the bricks manufactured with high amounts of clays were consciously chosen in the preparation of hydraulic mortars and plasters.     

Thermoelectric and Magnetic Properties of Pt-Substituted $${BaFe_{4-{x}}Pt_{{x}}Sb_{12}}$$ Compounds

\({BaFe_{4-{x}}Pt_{{x}}Sb_{12}}\) (x = 0, 0.1, 0.2) compounds were prepared by melting and annealing, followed by a spark plasma sintering method. Low-temperature thermoelectric and magnetic properties were investigated based on Seebeck coefficient, electrical and thermal conductivity and magnetization measurements. The structural properties of \({BaFe_{4-{x}}Pt_{{x}}Sb_{12}}\) (x = 0, 0.1, 0.2) compounds were ascertained by powder x-ray diffraction analysis, confirming that all samples have a main phase of a skutterudite structure with the space group Im\({\mathrm {\bar{3}}}\). The lattice parameters obtained, 9.202(5), 9.199(5) and 9.202(1) Å for x = 0, 0.1 and 0.2, respectively, were found consistent with literature. The Seebeck coefficient sign shows that holes are dominant carriers in all compounds. The local maximum Seebeck coefficient was observed around 50 K which may be a trace of paramagnon-drag effect of charge carriers. Thermal conductivity and electrical resistivity measurements were carried out between 4.2 and 300 K. Temperature dependence of electrical resistivity reflects that all samples show semi-metallic behavior in our temperature range of 4.2–300 K. Samples for x = 0.1 and x = 0.2 show Kondo-like behavior. In magnetization measurement, we observe that there are two successive magnetic transitions in Pt-substituted compounds; however, there is only one (transition from a paramagnetic state to long-range magnetic ordering) in Pt-free compounds. In Pt-substituted compounds, the first transition appears at \( T _{ {\rm c}}\) = 48 K. In addition, the second transition is observed at \( T _{ {\rm irr}}\) = 30 K where an intermediate state is observed before the magnetic ordering transforms to an irreversible ferromagnetic state. We concluded that Pt substitution on the Fe side effectual on the thermoelectric and magnetic properties of \({BaFe_{4-{x}}Pt_{{x}}Sb_{12}}\) (x = 0, 0.1, 0.2) compounds.     

Transient Temperature Analysis of Slab in Erdemir

A transient thermal model was developed for slab furnaces in Eregli Iron and Steel Works （Erdemir） in Turkey and the model was solved using the FlexPDE computer program. This program uses the finite element method. Program codes were written to solve the temperature distribution of slabs that are put into furnace at 25 ℃ and removed at about 1 250℃. To obtain the optimum slab exit temperature variation, the necessary air temperature inside the furnace was calculated to be 1 390℃. The slab temperature versus time and the temperature variation inside the slab were depicted.     

The Effects of Containment on Detonation Velocity

Reactive flow cylinder code runs on six explosives were made with rate constants varying from 0.03 to 70 μs⁻¹. Six unconfined/steel sets of original ANFO and dynamite data are presented. A means of comparing confinement effects both at constant radius and at constant detonation velocity is presented. Calculations show two qualitatively different modes of behavior. For U_s/C_o≥1.2, where U_s is the detonation velocity and C_o the zero‐pressure sound speed in steel, we find a sharp shock wave in the metal. The shock passes through the steel and the outer wall has a velocity jump‐off. For U_s/C_o≤1.04, we find a pressure gradient that moves at the detonation velocity. A precursor pulse drives in the explosive ahead of the detonation front. The outer wall begins to move outward at the same time the shock arrives in the explosive, and the outer wall slowly and continuously increases in velocity. The U_s/C_o≥1.2 cylinders saturate in detonation velocity for thick walls but the U_s/C_o<<1.04 case does not. The unconfined cylinder shows an edge lag in the front that approximately equals the reaction zone length, but the highly confined detonation front is straight and contains no reaction zone information. The wall thickness divided by the reaction zone length yields a dimensionless wall thickness, which allows comparison of explosives with different detonation rates. Even so, a rate effect is found in the detonation velocities, which amounts to the inverse 0.15–0.5 power.     

I5M: 3D widefield light microscopy with better than 100 nm axial resolution

Sevenfold improved axial resolution has been achieved in three-dimensional widefield fluorescence microscopy, using a novel interferometric technique in which the sample is observed and/or illuminated from both sides simultaneously using two opposing objective lenses. Separate interference effects in the excitation light and the emitted light give access to higher resolution axial information about the sample than can be reached by conventional widefield or confocal microscopes. Here we report the experimental verification of this resolution performance on complex biological samples.     

Transient liquid phase (tlp) diffusion bonding of Ti45Ni49Cu6 P/M components using Cu interlayer

In this study, transient liquid phase diffusion bonding parameters of Ti₄₅Ni₄₉Cu₆ P/M components using copper interlayer were experimentally investigated in a protective (argon) atmosphere. Bonding processes of sintered Ti₄₅Ni₄₉Cu₆ P/M compacts were carried out at various temperatures and bonding periods while bonding pressure was kept unchanged. The process pressure, 20 MPa, was selected just below those which would cause macro deformations. Optical microscopy, scanning electron microscopy, and energy dispersive spectroscopy were employed for microstructure examinations. Shear strength and hardness (HB) of bonded specimens were measured at bond interface and parent materials for mechanical property evaluations. Along the bond interface, copper, titanium, and nickel atom mutual migration was observed. Structural tests, metallographic analysis have shown the integrity of the diffusion bonded hardware, bonded between 940 and 970°C process temperatures, for 40–60-min bonding periods.