A heuristic approach to the generation of tests for faults on the intermediate lines

The paper deals with the study of test generation mechanisms for faults on the intermediate lines using Boolean matrices. The proposed technique is a novel approach to the problem and also aims at deriving the results heuristically, thus saving computational effort. The technique has been illustrated by suitable examples.     

Discriminatory experiments in high-resolution13C NMR of solid polymers

Summary Cross-polarization spectra of solid polymers can be misleading when the material exhibits proton spinlattice relaxation in the rotating frame which cannot be represented by a single exponential. Quantitative and qualitative demonstrations of the problem are given. The use of two experimental procedures for alleviating the difficulties is suggested, and examples for polyalkenes and for polyethylene terephthalate are illustrated.     

Pig prothrombin: purification and properties

A procedure for the preparation of highly purified pig prothrombin is described. Compared to the initial clotting activity of the starting plasma, this protein was purified 776 times with a final yield of 8 per cent. The purified zymogen showed a specific activity of 1,460 NH units/mg of protein , a molecular weight of 65,000 as determined by SDS-polyacrylamide disc gel electroesis, E 1.0 mg/ml 1.0 cm, 280 nm = 1.45 at pH 7.0 and the following amino acid composition: Asx 51, Thr 38, Glx 62, Pro 23, Gly44, Ala 25, Half-Cys 30, Val 35, Met 3, Ile 30, Leu 32, Tyr 19, Phe 22, Lys 36, His 8, Arg 28, and Trp 13, which accounts for a minimum molecular weight of 59,370 (carbohydrates not computed). Alanine was found as the only N-terminal residue. Carboxypeptidases A and B failed to release any C-terminal residue. By hydrazinolysis however 0.4 mole of serine was released per mole of prothrombin. The activation of crude and chromatographed pig prothrombin was investigated.     

Petri net approach to enumerate all simple paths in a graph

A technique utilising the concept of reachability in a Petri net is proposed to enumerate all simple paths between two specified nodes of a graph. It is simple and requires little computation.     

Quantification of trans fatty acid content in French fries of local food service retailers using attenuated total reflection – Fourier transform infrared spectroscopy

The contents of trans fatty acids in French fries served at the local food service retailers in Honolulu were determined by simple Fourier transform infrared (FTIR) spectroscopic technique without the pretreatment of fatty acid extraction. A horizontal attenuated total reflection (ATR) crystal made of zinc selenide (ZnSe) was used to obtain FTIR spectra of French fries with and without fatty acid extraction. Residual oil films obtained by pressing French fries directly on the ATR crystal surface without removal of any solid particles or air bubbles were scanned for the spectral measurement. The calibration set consisted of triolein (C18:1, 9-cis) and trielaidin (C18:1, 9-trans) mixed in varying ratios. All spectral data were averaged and converted into GRAMS format. The peak heights of each spectrum at 966 cm⁻¹ were found to be linearly correlated with the contents of trans fatty acids in the validation set (n = 8, R² = 0.9835). The developed calibration model was validated by comparing the results obtained from the ATR-FTIR with Mojonnier extraction and gas chromatography–mass spectrometry (GC–MS).     

Catalytic-free growth of VACNTs for energy harvesting

Abstract

The present study introduces a process to grow micro-honeycomb (µ-HC) vertically aligned carbon nanotubes (VACNTs) using thermal chemical vapor deposition technique. Methane is used as a source of carbon and hydrogen gas as a reducing agent. Where, the fabricated µ-HC structure reported in literature involves complex synthesis process and requires a catalyst layer, the novelty of the process used here lies in the fact that no catalyst layer is used for the growth of CNT network, rather copper foil is used as a substrate. The in-situ cracking of CNTs due to water treatment leads to the formation of µ-HC CNT network, which is confirmed by Raman spectroscopy. Further scanning electron microscopy analysis shows that the length of developed µ-HC CNT is ～5?µm. Hexagonal µ-HC network shows more than 94% absorption in UV-Vis-NIR wavelength region. The designed process provides high-yield with a low-cost synthesis of vertically aligned CNTs having 3?D microarchitecture. The fabricated CNT network can be used as an electrode for supercapacitor, as an active layer in a photovoltaic cell and most of the energy harvesting devices.     

Slurry Erosive Wear Evaluation of HVOF-Spray Cr2O3 Coating on Some Turbine Steels

In this study, Cr₂O₃ coatings were deposited on CF8M and CA6NM turbine steels by high-velocity oxy-fuel (HVOF)-spray process and analyzed with regard to their performance under slurry erosion conditions. High Speed Erosion Test Rig was used for slurry erosion tests, and the effects of three parameters, namely, average particle size, speed (rpm), and slurry concentration on slurry erosion of these materials were investigated. SEM micrographs on the surface of samples, before and after slurry erosion tests, were taken to study the erosion mechanism. For the uncoated steels, CA6NM steel showed better erosion resistance in comparison with CF8M steel. The HVOF-sprayed Cr₂O₃-coated CF8M and CA6NM steels showed better slurry erosion resistance in comparison with their uncoated counterparts. It may be due to the higher hardness as a result of HVOF-sprayed Cr₂O₃ coating in comparison with the uncoated CF8M and CA6NM steels.     

Investigations on the Behavior of HVOF and Cold Sprayed Ni-20Cr Coating on T22 Boiler Steel in Actual Boiler Environment

High temperature corrosion accompanied by erosion is a severe problem, which may result in premature failure of the boiler tubes. One countermeasure to overcome this problem is the use of thermal spray protective coatings. In the current investigation high velocity oxy-fuel (HVOF) and cold spray processes have been used to deposit commercial Ni-20Cr powder on T22 boiler steel. To evaluate the performance of the coatings in actual conditions the bare as well as the coated steels were subjected to cyclic exposures, in the superheater zone of a coal fired boiler for 15 cycles. The weight change and thickness loss data were used to establish kinetics of the erosion-corrosion. X-ray diffraction, surface and cross-sectional field emission scanning electron microscope/energy dispersive spectroscopy (FE-SEM/EDS) and x-ray mapping techniques were used to analyse the as-sprayed and corroded specimens. The HVOF sprayed coating performed better than its cold sprayed counterpart in actual boiler environment.