Optimization of flank wear using Zirconia Toughened Alumina (ZTA) cutting tool: Taguchi method and Regression analysis

In this study, Taguchi method and Regression analysis have been applied to assess machinability of AISI 4340 steel with newly developed Zirconia Toughened Alumina (ZTA) ceramic inserts. Several experiments have been carried out based on an orthogonal array L₉ with three parameters (depth of cut feed rate, cutting speed) at three levels (low, medium and high). Based on the mean response and signal to noise ratio (SNR), the best optimal cutting condition has been arrived at A₂B₁C₁ i.e. cutting speed is 280 m/min, depth of cut is 0.5 mm and feed rate is 0.12 mm/rev considering the condition smaller is the better approach. Analysis of Variance (ANOVA) is applied to find out the significance and percentage contribution of each parameter. It has been observed that depth of cut has maximum contribution on tool wear. The mathematical model of flank wear has been developed using regression analysis as a function of the above mentioned independent variables. The predicted value from the developed model and experimental values are found to be very close to each other justifying the significance of the model. A confirmation run has been carried out with 95% confidence level to verify the optimized result and the values obtained are within the prescribed limit.     

Optimisation of a process for production of pomegranate pulp and flaxseed powder fortified probiotic Greek dahi

Fortified probiotic Greek dahi was formulated with pomegranate pulp (PP) and flaxseed powder (FP). The product variables, viz. PP, FP and incubation time, were optimised based on chemical, sensory and textural attributes. The study revealed that PP significantly affected the acidity and antioxidant content, while FP influenced the sensory and textural properties of the product. The optimum conditions were 15% PP, 2% FP and 12‐h incubation time. The developed fortified probiotic Greek dahi is a potential synbiotic food.     

A Precision Ultrasonic Phase Velocity Measurement Technique for Liquids

Present paper reports the design and developmental aspects of a new technique for ultrasonic phase velocity measurement in liquids, which is based on the studies carried out on frequency dependence of ultrasonic velocity in pure, binary and ternary liquids/mixtures. The design and developmental aspects of the experimental set up are reported along with optimisation of data acquisition software developed in LabVIEW. Finally, the developed technique is used to measure phase velocity in water (W), aqueous solution of mannitol (M), binary mixture of tertiary butyl alcohol (TBA) in water and a tertiary mixture of TBA + W + M. The results are reported within frequency bandwidth from 3 to 7 MHz. The main reason for selecting these liquids was to identify some of the liquids which can be used as reference liquids for metrological applications. Although, reporting the systematic studies to find out the reference liquid is beyond the scope of the present paper due to obvious reasons, and will be dealt separately, but the studies certainly demonstrate that the technique can successfully be used for phase velocity measurement as a function of frequency and temperature.     

Solid phase extraction of lead on octadecyl bonded silica membrane disk modified with Cyanex302 and determination by flame atomic absorption spectrometry

A simple, reliable and rapid method for preconcentration and determination of lead using octadecyl bonded silica membrane disk impregnated with Cyanex302 and flame atomic absorption spectrometry is presented. The influence of aqueous phase pH, type of eluent, flow rates of sample solution and eluent, volume of eluent and amount of extractant has been investigated. The break through volume is greater than 4.0 dm(3) with an enrichment factor of more than 400 and a detection limit of 1.0microg dm(-3). The method developed for determination of lead is good as six replicate determinations using 100cm(3) solution containing lead in the range 1-4900microg provides a relative standard deviation (R.S.D.) of 0.4%. The selectivity of the proposed method was confirmed from the interference studies. The developed procedure was successfully applied for the determination of lead in spiked sea water, USGS standard soil sample, sludge and industrial effluents, medicinal formulation, plant, some food products and wine.     

Processing and properties of sol gel derived alumina–carbon nano tube composites

High purity alumina–carbon nano tube (CNT) composites were prepared by an aqueous sol–gel processing route. CNTs were dispersed in alumina sol containing appropriate amount of MgO precursor. Aqueous slurry of alumina was seeded into the sol followed by gelation, drying and calcination at 1000 °C for 1 h. The calcined powder consisting of alumina-coated CNTs and alumina was milled, sieved, dried, pressed and pressureless sintered at 1400–1600 °C for 1 h in nitrogen atmosphere. Sintered samples were further isostatically hot pressed at 1300 °C and the properties were compared with the pressureless sintered samples. Phase formation was followed by XRD study, CNT retention was confirmed by Raman studies and the samples were further characterized for mechanical and microstructural properties.     

Detection of E. coli O157:H7 from Ground Beef Using Fourier Transform Infrared (FT-IR) Spectroscopy and Chemometrics

Abstract: FT-IR spectroscopy methods for detection, differentiation, and quantification of E. coli O157:H7 strains separated from ground beef were developed. Filtration and immunomagnetic separation (IMS) were used to extract live and dead E. coli O157:H7 cells from contaminated ground beef prior to spectral acquisition. Spectra were analyzed using chemometric techniques in OPUS, TQ Analyst, and WinDAS software programs. Standard plate counts were used for development and validation of spectral analyses. The detection limit based on a selectivity value using the OPUS ident test was 10⁵ CFU/g for both Filtration-FT-IR and IMS-FT-IR methods. Experiments using ground beef inoculated with fewer cells (10¹ to 10² CFU/g) reached the detection limit at 6 h incubation. Partial least squares (PLS) models with cross validation were used to establish relationships between plate counts and FT-IR spectra. Better PLS predictions were obtained for quantifying live E. coli O157:H7 strains (R²≥ 0.9955, RMSEE ≤ 0.17, RPD ≥ 14) and different ratios of live and dead E. coli O157:H7 cells (R²= 0.9945, RMSEE = 2.75, RPD = 13.43) from ground beef using Filtration-FT-IR than IMS-FT-IR methods. Discriminant analysis and canonical variate analysis (CVA) of the spectra differentiated various strains of E. coli O157:H7 from an apathogenic control strain. CVA also separated spectra of 100% dead cells separated from ground beef from spectra of 0.5% live cells in the presence of 99.5% dead cells of E. coli O157:H7. These combined separation and FT-IR methods could be useful for rapid detection and differentiation of pathogens in complex foods.     

Influence of the heat exchangers’ construction material on catalytic incineration

In industrial scale catalytic volatile organic compounds (VOCs) incineration it is sometimes observed that the VOC conversions are higher than expected, based on the laboratory scale experiments at the same temperatures. One reason for this is that the construction material of the industrial scale catalytic incinerator may have an effect on the total VOC conversion. In this study, the effect of construction material on VOC removal activity is studied through laboratory experiments, by thermodynamic calculations and by flow modelling. The results showed that copper and Aluzinc decreased the light-off temperature (T₅₀) of n-butyl acetate compared to thermal experiments. Copper and Aluzinc did not, however, further decrease the T₅₀ when they were introduced into the reactor packed with the catalyst. The higher total VOC conversion observed in the industrial scale incinerator is presumably due to the higher temperatures at the outlet of the catalyst, which is maintained by the heat exchangers.     

Cellulase production using biomass feed stock and its application in lignocellulose saccharification for bio-ethanol production

A major constraint in the enzymatic saccharification of biomass for ethanol production is the cost of cellulase enzymes. Production cost of cellulases may be brought down by multifaceted approaches which include the use of cheap lignocellulosic substrates for fermentation production of the enzyme, and the use of cost efficient fermentation strategies like solid state fermentation (SSF). In the present study, cellulolytic enzymes for biomass hydrolysis were produced using solid state fermentation on wheat bran as substrate. Crude cellulase and a relatively glucose tolerant BGL were produced using fungi Trichoderma reesei RUT C30 and Aspergillus niger MTCC 7956, respectively. Saccharification of three different feed stock, i.e. sugar cane bagasse, rice straw and water hyacinth biomass was studied using the enzymes. Saccharification was performed with 50 FPU of cellulase and 10 U of β-glucosidase per gram of pretreated biomass. Highest yield of reducing sugars (26.3 g/L) was obtained from rice straw followed by sugar cane bagasse (17.79 g/L). The enzymatic hydrolysate of rice straw was used as substrate for ethanol production by Saccharomyces cerevisiae. The yield of ethanol was 0.093 g per gram of pretreated rice straw.     

Phase and interference properties of optical vortex beams

Laguerre-Gauss vortex beams carrying different topological charges are generated from Hermite-Gauss laser beams emitted by a gas laser, and their phase properties are explored by studying their interference with a plane wave. Interference of two Laguerre-Gauss vortex beams carrying equal but opposite topological charge is also studied by using a modified Mach-Zehnder interferometer. Experimentally recorded intensity profiles are in good agreement with the theoretically expected profiles.