On modification of the relative complexity metric

Software reliability and software complexity are closely related issues in software development. An elegant definition of relative complexity was proposed in [1,2]. The definition given in [1,2] needs modification. Depending on how many factor loadings are used in the factor analysis different complexity results are obtained. Hence the definition of relative complexity given in those papers is subjective. The object of this paper is to suggest a modified definition of relative complexity. Different measures based on the magnitude of the eigenvalues obtained from the correlation matrix are suggested in this paper. The relative complexity of 27 programs given in [3] has been calculated using different factor loadings.     

Comparative Study of Silver Nanoparticles Coated and Uncoated NiO–Fe2O3–CaO–SiO2–P2O5 Ferromagnetic Bioactive Ceramics

Bioactive ferromagnetic ceramics of system xNiO–(3?x)Fe₂O₃–52CaO–30SiO₂–15P₂O₅, (x = 0, 3 mol%) have been prepared in the laboratory using sol–gel technique. Silver nanoparticles coating has been undertaken on the surface of synthesized samples. Comparative study of silver nanoparticles coated and uncoated samples has been undertaken with the help of transmission electron microscopy, X‐ray diffraction (XRD), degradation, drug delivery, hemolysis, antimicrobial, and cell culture studies. XRD patterns indicate the growth of hydroxyl apatite layer on the surface of coated as well as uncoated samples. Ferromagnetic properties of samples have been investigated with the help of vibrating sample magnetometer technique. Samples have shown good response as drug carriers under normal conditions as well as under the influence of magnetic field. Drug release mechanism and mesoporus nature of samples have been investigated with the help of Brunauer–Emmett–Teller technique. Nonreactivity of samples (coated and uncoated) with red blood cells and white blood cells show nontoxic nature of the samples. Coated samples have shown better antimicrobial properties against six different microorganisms, including some resistive strain like methicillin‐resistant Staphylococcus aureus with minimum inhibitory concentration of 0.05 mg/ml as compared to uncoated samples. It has been observed that samples also provide a healthy environment for the growth of MG 63 cell lines. It has been noticed that presence of silver nanoparticles on the surface of samples improve degradation and antimicrobial properties.     

Correction to: Analysis of Water Quantity and Quality Trade‑Offs to Inform Selective Harvesting of Inflows in Complex Water Resource Systems

Water Resources Management -     

Energy and protein requirements of guinea keets (Numida meleagris) as meat bird in a hot humid climate

Energy and protein requirements of guinea keets (Numida meleagris) in a hot humid climate were determined involving one day‐old keets of three varieties: Pearls, Lavender and White. Nine dietary treatments combining three levels of metabolisable energy (ME) and crude protein (CP) were offered during each growth phase (0–4, 5–8 and 9–12 weeks of age). Crude protein levels were P₁ , 220, 200 and 180; P₂ , 200, 180 and 160; and P ₃ , 180, 160 and 140 g kg⁻¹ dry mash for respective phases, while ME levels were E₁, 12.13 and 12.55; E₂ , 11.72 and 12.13; and E₃ , 11.30 and 11.72 MJ kg⁻¹ dry matter for 0–4 and 5–12 weeks of age, respectively. The live weight gain during 0–12 weeks of age at different energy levels (E₁ , 751; E₂ , 775 and E₃ , 755) were comparable, but those at different protein levels (P₁ , 847; P₂ , 804 and P₃ , 633) were different (P<0.01). Keets fed either 180 g or 160 g CP kg⁻¹ during 9–12 weeks of age had similar gains. Feed conversion ratios (FCR) during 0–12 weeks on E₁P₁ (3.50), E₂P₁ (3.47) and E₃P₁ (3.47) did not differ significantly. At 4 weeks of age, FCR on the three energy levels were similar but the cumulative FCR on E ₁ (3.67) and E₂ (3.65), although similar, were improved (P<0.05) compared to that on E₃ (3.87). Thus, the requirements of ME are 11.30 and 12.13 MJ kg⁻¹ dry mash during, 0–4 and 5–12 weeks of age with 220, 200 and 160 g CP kg ⁻¹ during 0–4, 5–8 and 9–12 weeks of age, respectively. © 1999 Society of Chemical Industry     

A new formulation for state equation representation for Petri nets

A new algorithm for determination of state equations for Petri nets has been proposed. The proposed algorithm results in state equations similar to the state equations for linear sequential machines. All Petri nets may not be represented in the form of linear sequential machines. The resulting state equations are different from Petri net state equations and include output equations used in control theory literature.     

Metallurgical and mechanical characteristics of cryogenically treated tungsten carbide (WC–Co)

This paper aims to present the metallurgical and mechanical characterization of cryogenically treated tungsten carbide (WC–Co) in terms of α-, β-, γ-, and η-phase particles and wear behavior, respectively. The specimens of commercially available uncoated WC–Co in the form of round turning inserts were procured and subjected to cryogenic treatment at two levels ?110°C (shallow treatment) and ?196°C (deep treatment) of temperature. The microstructures obtained after cryogenic treatments have been characterized with a prominence to comprehend the influence of cryogenic treatment on the nature, size, and distribution of α-, β-, γ-, and η-phase particles as compared to untreated specimen. The mechanical properties such as hardness and wear rate of the specimens have also been compared by performing Rockwell A hardness test and pin-on-disk wear test, respectively. Microstructures, hardness, wear rate, and analysis of worn surface divulge the underlying metallurgical mechanism responsible in improving mechanical properties of the WC–Co.     

Wear behaviour of cryogenically treated tungsten carbide inserts under dry and wet turning conditions

Cryogenic treatment has been acknowledged as a means of extending the life of tungsten carbide inserts but no study has been reported in open literature regarding the effect of coolant on the performance of cryogenically treated tungsten carbide inserts in turning. In order to understand the effect of coolant, a comparative investigation of the wear behaviour of cryogenically treated tungsten carbide inserts in dry and wet orthogonal turning has been carried out in this study. The commercially available uncoated square-shaped tungsten carbide inserts with chip breakers were procured and cryogenically treated at ?196 °C and the cutting tests were executed in accordance to the International Standard Organisation, ISO 3685-1993 for continuous and interrupted machining mode. The criterion selected for determining the tool life was based on the maximum flank wear (0.6 mm) and the selection of cutting conditions was made to ensure the significant wear at a suitable time interval. The results showed that cryogenically treated tungsten carbide inserts performed significantly better in wet turning conditions under both continuous and interrupted machining modes especially at higher cutting speeds. A considerable increase in tool life was also recorded in interrupted machining mode as compared with continuous machining mode.     

Production of Nanocrystalline Ni-20Cr Coatings for High-Temperature Applications

Presynthesized nanocrystalline Ni-20Cr powder was deposited on SA 516 and T91 boiler steels by a high-velocity oxy-fuel spraying process. Ni-20Cr powder was synthesized by the ball milling approach. The high-temperature oxidation behavior of bare and coated samples was then studied under cyclic isothermal conditions at 900 °C for 50 cycles. The kinetics of oxidation was established using weight change measurements for the bare and coated boiler steels. Uncoated and coated samples of T91 steel were exposed to the superheated zone of a power plant boiler at 750 °C under cyclic conditions for 15 cycles. Each cycle consisted of 100 h of heating followed by 1 h of cooling. Attempts were made to study the kinetics of erosion–corrosion using weight change and thickness loss data for the samples. Different characterization techniques were used to study the oxidized and eroded–corroded samples, including x-ray diffraction, scanning electron microscopy/energy-dispersive spectroscopy, and x-ray mapping analyses. The Ni-20Cr alloy powder coating was found to offer excellent oxidation resistance to the base steels and was successful in reducing the weight gain of SA 516 steel by 98.5 % and that of T91 steel by 65 %. The coating was observed to reduce the erosion–corrosion rate of T91 steel by 86 % in terms of thickness loss. This indicates that the investigated nanostructured coating can be a better choice over conventional coating for erosion–corrosion control of boiler tubes.     

Surface engineering analysis of detonation-gun sprayed Cr3C2–NiCr coating under high-temperature oxidation and oxidation–erosion environments

Detonation-gun (D-gun) spray technology is a novel coating deposition process which is capable of achieving very high gas and particle velocities approaching 4–5 times the speed of sound. This process provides the possibility of producing high hardness coatings with strong adherence. In the present study, this technique has been used to deposit Cr₃C₂–NiCr coating on T22 boiler steel. Investigations on the behaviour of this coating subjected to high-temperature oxidation in air and oxidation–erosion in actual boiler environment at 700 ± 10 °C under cyclic conditions have been carried out. The weight change technique was used to establish the kinetics of oxidation. X-ray diffraction (XRD), field emission-scanning electron microscopy/energy-dispersive spectroscopy (FE-SEM/EDS) and EDS elemental mapping techniques were used to analyse the oxidation/oxidation–erosion products. The uncoated boiler steel suffered from a catastrophic degradation in the form of intense spalling of the scale in both the environments. The Cr₃C₂–NiCr coating showed good adherence to the boiler steel during the exposures with no tendency for spallation of its oxide scale.     

Effects of hBN and Y2O3 Addition on Mechanical and Tribological Behavior of SiC Ceramic Matrix Composites Prepared by Spark Plasma Sintering

Silicon - The objective of the present work is to study the mechanical and tribological properties of SiC-hBN such as hardness, density, fracture toughness, friction and wear behavior with and...