Search

X-ray diffraction analysis revealed that pentlandite and chalcopyrite were the prominent mineral phases in a South African sulfidic nickel ore concentrate that hosted nickel and copper. Cobalt was found to be closely associated with the nickel-bearing pentlandite phase of the ore sample. Microbial batch leaching experiments designed according to a central composite design model were run for 15 days in a shaking incubator (150 rpm) at a constant temperature (30°C) with variations in experimental parameters like ore pulp density, particle size, bacterial inoculum, pH of the culture medium, and residence time. Quadratic mathematical models were developed to predict the rate of metal extractions. The suitability of the model of the microbial leaching process was confirmed from normal probability curves. An analysis of variance indicated that the residence time, pulp density of the ore, and particle size were the most significant factors. Bacterial inoculum size hardly showed any effect on the total metal extractions. Maximum nickel (82%), cobalt (76%) and copper (25.6%) extractions were achieved under optimum conditions, operated for 15 days at pulp density of 2% and particle size of −75 µm at pH 1.5. [ABSTRACT FROM AUTHOR]

This work addresses the Magnetostrictive effect in ferromagnetic components. Due to extensive use of ferromagnetic materials in practical engineering such as transducers, nuclear reactors, aerospace components and electric motor where magnetic field is dominant, this strain cannot be neglected. This work signifies the modelling and simulation of the three dimensional rectangular bar, fixed at one end and subjected to external magnetic field. The stress and strain developed due to magnetostrictive effect are simulated and dependency of the mathematical model has been observed on different parameters like magnetic field and current density with respect to strain. The magnetostrictve material surrounded by drive coil modelled as homogenized current carrying domain. The flux leakage is minimized by modelling a steel housing to create closed magnetic flux path. The problem is modeled and simulated in combined study of Magnetic Field and Static Structure in COMSOL Multiphysics 5.2. Result obtained involves significant strain in the core which can't be ignored in the engineering applications and can affect various design parameters if ignored. The strain caused due to magnetostrictive effect has been verified by existing empirical strain model. [ABSTRACT FROM AUTHOR]

Bruchids ( Callosobruchus spp.) are recognised as the most detrimental storage pest of pulses, especially in the tropics and subtropics. They invade matured pods as well as seeds during storage and, to some extent, farming fields, in turn reducing the net yield of the crops. Several approaches including cultural, biological, physical and chemical control measures have been implemented with the aim of managing these pests, but none of these have been successful across time and space. Recently, transgenic- and marker-assisted breeding approaches have appeared as promising tools for the successful management of these pests. Although some efforts have been made on the development of bruchid-resistant transgenic crops, the cultivars developed are yet to be commercialised worldwide because of various limitations. In contrast, marker-assisted breeding involving the identification of DNA-based markers linked to host resistance against bruchids, have shown some success in the quest for the development of bruchid-resistant cultivar(s). DNA markers linked to bruchid resistance have been identified in various grain legumes, particularly in the genus Vigna, and include mung bean ( Vigna radiata), azuki bean ( Vigna angularis), rice bean ( Vigna umbellata), cowpea ( Vigna unguiculata) and black gram ( Vigna mungo). After their validation in different genetic backgrounds, these markers could be utilised for marker-assisted selection and breeding ventures to protect pulse crops. The present study discusses the pros and cons of different approaches for the successful management of the bruchid pests in pulses. The review also highlights about the integrative approach aided with molecular interventions to improve productivity by avoiding losses incurred due to bruchids, and to attain sustainable yields for major pulse crops. [ABSTRACT FROM AUTHOR]