Biotic elicitors enhance flavour compounds during accelerated curing of vanilla beans

Food-grade elicitors, selected after an initial screening, were used in combination with pre-treatments for the accelerated curing of beans. When acetone dried red beet elicitor – a rich source of peroxidase (98,500 U g⁻¹ dry weight) was used, 2.65% vanillin was formed in 10 days, which was 1.7-fold higher than in control beans (blanched + scarified) of this study and 3.23-fold higher than the conventional curing (0.82%). HPLC analysis of elicitor-treated samples showed the formation of almost all the major compounds found in the conventionally cured beans (cured for 3–6 months) with better sensorial properties. These observations appear useful for developing a rapid process for the curing of vanilla beans.     

Surface properties of electrodeposited a-Si:C:H:F thin films by X-ray photoelectron spectroscopy

Surface properties of amorphous silicon thin films containing hydrogen, flourine and carbon obtained from hydrofluosilicic acid and ethylene glycol using the electrodeposition method are reported as a function of current density and deposition time. The Si2p core level X-ray photoelectron spectra exhibited binding-energy shifts corresponding to SiFx (x=1–4), SiC, Si-H and Si-O2 type bond formations. The shifts in 1s spectra of fluorine, carbon and oxygen confirmed the presence of fluorine, carbon and oxygen in bonded form. Theoretical binding-energy shifts calculated from Pauling's electronegativity values were in close agreement with the measured values. The relative concentration values of C/Si estimated in these films were found to be larger than those of F/Si and O/Si. The results were corroborated with infrared spectroscopy and scanning electron microscopy data. This revised version was published online in November 2006 with corrections to the Cover Date.     

Predictive modeling of transition undeformed chip thickness in ductile-regime micro-machining of single crystal brittle materials

This paper proposes a predictive model to determine the undeformed chip thickness in micro-machining of single crystal brittle materials, where the mode of chip formation transitions from the ductile to the brittle regime. The comprehensive model includes a force model considering the rounded tool edge radius effect and ploughing. Irwin's model for computing the stress intensity factor is adopted here as it gives a relation between the stress intensity and applied normal stress including effects of crack size and crack inclination. The occurrence of plastic deformation is built upon the condition that the shear stress in the chip formation region must be greater than the critical shear stress for chip formation and the stress intensity factor must be less than the fracture toughness of the material. The point of transition takes place when the fracture toughness is equal to the stress intensity factor. The above conditions form the theoretical basis for the proposed model in determining the transition undeformed chip thickness. End-turning experiments have been conducted using a single crystal diamond cutting tool on (1 1 1) single crystal silicon, and the results compared to the model predictions for validation. The proposed model would support the determination of the cutting conditions for the micro-machining of a brittle material in ductile manner without resorting to trial and error.     

Electrochemical Deposition of 58SiO2‐33CaO‐9P2O5 Nanobioactive Glass Particles on Ti‐6Al‐4V Alloy for Biomedical Applications

The nanobioactive glass (58SiO₂‐33CaO‐9P₂O₅) powders were synthesized by simple sol–gel method. The prepared samples reveal amorphous nature, agglomerated spherical morphology with particle size of 100–150 nm. The specific surface area of nanobioactive glass (NBG) particle is 147 m²/g. The NBG samples were coated on titanium (Ti‐6Al‐4V) alloy through electrochemical deposition method. The particle size of the NBG‐coated surface was in the order of 200–300 nm, and it was confirmed by atomic force microscopy (AFM) analysis. In vitro and AFM studies reveal the existence of higher bioactivity and uniform coating of NBG on implants at 80 V for 1 h.     

Ion beam characterization of rf-sputter deposited AlN films on Si(1 1 1)

Aluminum nitride (AlN) thin films have been deposited on Si(1 1 1) substrates by using reactive-rf-magnetron-sputtering at 250 °C. The crystalline quality and orientation of the films have been studied by X-ray diffraction (XRD). We have observed that the films grow with c- or a-axis orientation. The composition, film thickness, impurities and stress are considered to be factors affecting the orientation and have been analyzed by Rutherford backscattering spectroscopy (RBS), nuclear reaction analysis (NRA) and XRD. Their effects on the film growth will be discussed. Surface morphology of the films will be also presented.     

A note on the three-point method for roundness measurement

This technical note presents two enhancements to three-point method for roundness measurement. They enable measuring a larger bandwidth and also present a logical progression from two-point profile to three-point roundness measurement using the combined method. Simulated profiles with and without step variations are used to demonstrate these improvements.     

Production of Al2O3‐Stabilized Tetragonal ZrO2 Nanoparticles for Thermal Barrier Coating

Al₂O₃‐stabilized tetragonal ZrO₂ nanoparticles were obtained through hot‐air spray pyrolysis and characterized after postsynthesized treatments. The produced nanoparticles were 26 nm in size with surface area of 59 m²/g. A multilayer thermal barrier coating of nanostructured Al₂O₃‐ZrO₂‐embedded silicate was applied to the mild steel (EN3) specimen using spin‐coating technique and characterized comprehensively employing X‐ray diffraction and scanning electron microscope. The Al₂O₃‐stabilized ZrO₂ with silicate matrix facilitates the formation of zirconium silicate nanostructured surface‐protective coating on EN3 specimen. The Al₂O₃‐ZrO₂/SiO₂ matrix‐based hybrid inorganic coating shows effective thermal barrier for EN3 after firing at a high temperature of 600°C.     

Pulsed electrogeneration of bubbles for electroflotation

Fine bubbles of the size required for many processes such as electroflotation can be generated by electrolysis. A large number of factors such as electrode material, electrode surface/morphological properties, pH and current density affect the gas bubble size distribution. This work is aimed at studies on the effect of interrupted current (pulsed) electrolysis on the generation of gas bubbles. A microcomputer-controlled current source designed to generate the required pulses is described along with typical results obtained with this system. It was observed that a decrease in duty cycle at a given pH and average current density causes an increase in fine sized bubbles and concomitant increase in bubble flux. A mechanism based on local potential gradients is proposed to explain this phenomenon.     

Microprocessor based TCR measurement and grading of resistors

The temperature Co-efficient of Resistance (TCR) is an important factor contributing to the functional accuracy of the systems. It is expressed in Parts Per Million (PPM). The TCR has to be measured accurately as the final finished product is coming out in an automatic process. Based on the measurement, the resistors are to be graded and sorted out. All these operations should take place without any interruption in the manufacturing process. This paper presents a microprocessor based system, which is very ideal for the measurement of TCR and sorting in a continuous batch process in the manufacturing of Resistors.     

Electrochemical dissolution of mild steel by alternating current

The electrochemical dissolution of mild steel in hydrochloric acid and sulphuric acid by a.c. has been studied. It has been found that with sine wave a.c. (50 Hz) the dissolution efficiency increases with increase in concentrations of the acids and decreases with the progress of electrolysis. As current density increases an initial increase in the efficiency was noticed; but as current density increases further, the efficiency falls. With square wave a.c. of low frequency (0.5 Hz), the dissolution efficiency increases with increasing concentrations of the acids and also with increasing frequency. However the efficiency decreases with increasing current density and time of electrolysis.