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MHD nanofluid flow past a rotating disk with thermal radiation in the presence of aluminum and titanium alloy nanoparticles
The effects of thermal and exponential space dependent heat sources (THS and ESHS) on magneto-nanoliquid flow across a rotating disk with uniform stretching rate along radial direction are scrutinized in this communication. H2O based nanoliquids containing aluminium (AA 7075) and titanium (Ti6Al4V) alloy nanoparticles are considered. The AA7075 is made up of 90% Al, 5-6% Zn, 2-3% Mg, 1-2% Cu with additives such as Fe, Mn and Si etc. The flow is driven due to rotating disk with uniform stretching of the disk. Impacts of Joule and viscous heating are also deployed. The multidegree ordinary differential equations are formed via Von Karman transformations. The obtained non-linear BVP is solved by Runge-Kutta-Fehlberg based shooting approach (RKFS). Graphical illustrations depict the impacts of influential parameters on flow fields. The skin friction and Nusselt number are also calculated. Results pointed out that the thermal boundary layer growth stabilizes due to the influence of ESHS aspect. Velocities of AA7075 H2O nanofluid are superior than that of Ti6 Al4V H2O nanoliquid. Furthermore, the thermal performance of base liquid is outstanding when we added titanium alloy nanoparticles in comparison with aluminium alloy nanoparticles. 2018 Trans Tech Publications, Switzerland. -
MHD nanofluid flow through Darcy medium with thermal radiation and heat source
In this analysis, we have considered heat transmission in two-dimensional steady laminar nanouid ow past a wedge. Magnetohydrodynamic (MHD), Brownian motion, viscous dissipation and thermophoresis eects are considered over the porous surface. Similarity transformations have been used to change the governing partial dierential equations (PDEs) into nonlinear higher-order ordinary dierential equations (ODEs). Governing ODEs with boundary conditions are then converted to the system of first-order initial value problem. After that the modeled system is solved numerically by RK4 technique. Impact of the magnetic number, Eckert number, Prandtl number, Lewis number, Brownian motion, thermophoresis and permeability parameters on the ow domain is analyzed graphically as well as in tabular form. It is noted that magnitude of Nusselt number for the ow regime increases with the increase of nondimensional parameter Pr; Nb; Nt while opposite behavior is observed in case of R. World Scientific Publishing Company. -
Micro and nano Bi2O3 filled epoxy composites: Thermal, mechanical and ?-ray attenuation properties
Polymer composites have attracted considerable attention as potential light-weight and cost-effective materials for radiation shielding and protection. In view of this, the present work focusses on development of lead-free composites of diglycidyl ether of bisphenol A (DGEBA) epoxy resin with micro (~ 10 ?m) and nano (~ 20 nm) bismuth (III) oxide (Bi2O3) fillers, using solution casting technique. Thermal, mechanical and ?-ray attenuation properties of the composites were studied by varying the filler loading. Inclusion of the fillers into epoxy matrix was confirmed both structurally and morphologically by XRD and SEM, respectively. Thermogravimetric analysis (TGA) showed the thermal stability of composites to be as high as 400 C. The nanocomposites exhibited relatively higher thermal stability than their micro counterparts. Among the composites, 14 wt% nano-Bi2O3/epoxy composites showed highest tensile strength of 326 MPa, which is about 38% higher than 30 wt% micro Bi2O3/epoxy composites. Mass attenuation coefficients (?/?) of the composites were evaluated at ?-ray energies ranging from 0.356 to 1.332 MeV. Nanocomposites showed better ?-ray shielding at all energies (0.356, 0.511, 0.662, 1.173, 1.280 and 1.332 MeV) than micro composites with same filler loading. These studies revealed the significance of nano-sized fillers in enhancing overall performance of the composites. 2021 Elsevier Ltd -
Micro Borrowing an Amalgam of Structure and Strategy: Evidence from India
Micro borrowing was either an outcome of structure in the credit environment (termed the outreach stream), or a strategic response of the borrowers (termed the sustainability stream). Furthermore, borrower personal effects drove borrowing behaviour. This study draws variables from both the streams of literature and tests them against the amount borrowed and purposes loans are borrowed for. Results show how borrowing behaviour is neither an outcome of pure structure nor pure strategy, but rather, is an interplay of both, and further influenced by personal effects. The survey data (consisting of 839 rural borrower responses, from four districts of erstwhile Andhra Pradesh in South India) was subjected to a rigorous statistical analysis. Results show how a larger number of banks in the villages (a structural constraint), enabled the borrowers to receive larger loans, who defaulted more (a strategic response). Men borrowed larger sums (a personal effect). A similar amalgam of structure, strategy and personal effects drive borrowing behaviour even after controlling for loan purpose and district fixed effects. Yet, when district effects are introduced, amount borrowed is agnostic to personal effects, and is driven purely by structure and strategy. JEL Classifications: C25, C83, G51, Z13 2022 SAGE Publications India Pvt. Ltd. -
Micro grid Communication Technologies: An Overview
Micro grid is a small-scale power supply network designed to provide electricity to small community with integrated renewable energy sources. A micro grid can be integrated to the utility grid. Due to lack of computerized analysis, mechanical switches causing slow response time, poor visibility and situational awareness blackouts are caused due to cascading of faults. This paper presents a brief survey on communication technologies used in smart grid and its extension to micro grid. By integration of communication network, device control, information collection and remote management an intelligent power management system can be achieved 2022 IEEE. -
Microalgae: a promising tool for plastic degradation
The use of plastics in the present-day routine is an unavoidable part of human life. It is posing a global environmental threat due to its never-ending accumulation. Complete disposal of plastics is a major problem, and for their complete degradation an effective solution or method has not been discovered yet. However, in order to turn to a biological approach for coping with the ever-increasing fear of plastic aggregation and decay, the development of a methodology would be useful for posterity. To eliminate plastic wastes, two scenarios exist: produce biodegradable plastics from renewable materials or fossil fuels as building blocks, such as hydrobiodegradable/oxo-biodegradable; or find appropriate microalgae and their toxins for the development of a protocol to effectively biodegrade the plastics. Just as biodegradation of plastics is a constructive option, as they are eco-friendly with not much harm done to the environment, the development of biodegradable plastic is also equally effective. Some of the algae that are isolated from the plastic wastes are green-algae, blue-green algae, diatoms, etc. Polyethylene is basically carbon and hydrogen polymer, which is exceptionally resistant to biodegradation (less than 0.5% over 100 years), whose degradation is dependent mainly on moisture, light, and temperature. The most used types of plastics like polyethylene terephthalate and polypropylene are a major threat as they are used in the manufacture of bottles, fibers, packing materials, etc. The degradation or disposal of these plastics is leading to their conversion into microsized particles which is further leading to harm to the environment, mainly when these microplastics interact with microalgae like Spirulina. However, landfill, incineration, and chemical methods are some of the conventional methods for polyethylene disposal that are fatal to the environment as they cause hazardous effects on flora and fauna. 2022 Elsevier Inc. All rights reserved. -
Microbial Decomposition of Feather Waste
Keratin is generally found as an ?-keratin helix form in hair, nails, horns and ?-keratin sheet form found in feathers, scales, beaks and claws. ?-keratin contains a domain rich in residues favoring to form ?-sheet structures associated with the filament framework. 'N' and 'C' terminal domains are associated with the matrix and forms cross-linking via disulfide bonds. Several million tons of feather waste are generated by poultry industries each year. Since this waste is rich in protein, it contains excellent potential as a protein source for animal feed and other applications.Bacterial and fungal strains used in microbial degradation of feathers are summarized. Various species from the bacterium genus are involved in keratin degradation including Bacillus, Stenotrophomonas, Pseudomonas, Brevibacillus, Fusarium, Geobacillus, Chryseobacterium, Xanthomonas and Serratia which are some keratin degrading bacteria. Actinomycetes and fungi also contribute to feather degradation by the enzyme activity of keratinases. 2022 World Research Association. All rights reserved. -
Microbial engineering strategies for synthetic microplastics clean up: A review on recent approaches
Microplastics are the small fragments of the plastic molecules which find their applications in various routine products such as beauty products. Later, it was realized that it has several toxic effects on marine and terrestrial organisms. This review is an approach in understanding the microplastics, their origin, dispersal in the aquatic system, their biodegradation and factors affecting biodegradation. In addition, the paper discusses the major engineering approaches applied in microbial biotechnology. Specifically, it reviews microbial genetic engineering, such as PET-ase engineering, MHET-ase engineering, and immobilization approaches. Moreover, the major challenges associated with the plastic removal are presented by evaluating the recent reports available. 2022 Elsevier B.V. -
Microbial Enzymes for Synthesis of Chiral Drug Intermediates
Microbes or microbial enzymes can catalyze the synthesis of bioorganic compounds, and this process is defined as biocatalysis. Biocatalysis has become an essential technique in organic biotransformation, typically applied in chemical industries. Biocatalysts generally show high activity and excellent enantio, stereo, regio, and chemo-selectivity. They offer practical and cost-effective ways to synthesize semi-synthetic analogues and novel drug molecules. Many bacteria and fungi-derived enzymes could catalyze highly specific hydroxylations of various substrates that are highly complex to synthesize by chemical methods. This chapter details and discusses different biocatalytic microbial platforms that permit to produce the chiral drug intermediates. 2023 selection and editorial matter, Ranjna Sirohi, Amit Kumar Rai, Luciana Porto de Souza Vandenberghe, and Binod Parameswaran; individual chapters, the contributors -
Microbial fuel cells for electricity generation and environmental bioremediation
The environmental impact on the use of fossil fuels and their unsustainable nature has led to the development of techniques using renewable energy and fuel cells. The recent decade has captured the attention of scientists towards the importance of microbial fuel cells (MFCs) with the role of microbial ability in converting organic wastes directly to electricity through microbially catalyzed anodic reactions along with microbial/enzymatic cathodic electrochemical reactions. MFC represents an environmental friendly approach for the use of generating electricity using wastewater, thus ensuring a bioremedial approach for effluent treatment with the achievement of chemical oxygen demand (COD) of about 50% chemical oxygen demand and power densities. This MFC utilises microbial metabolism for electricity generation. The overall performance of electricigens or MFC is based on the reactor design, operating conditions, electrode material used, types of substrates, and microorganisms involved. The optimization parameters studies for commercial production and their applications for MFC need to be intensified. Microbes have applications as biopolymer electrolytes that can be variously used in the applications of batteries, fuel cells and dye-sensitized solar cells. The use of MFCs has many advantages as they are eco-friendly, they have high performance abilities and they are costeffective and therefore can be used for modern applications. 2022 by Nova Science Publishers, Inc. -
Microbial Fuel Cells: The Microbial Route for Bioelectricity
The quest for sustainable energy sources serves as the essential pillar for development of humans since the dawn of civilization. The alarming increase in demand of energy, especially electricity propelled the need to screen for alternative sources of energy over the conventional fossil based non-renewable counterparts. Electricity generation through microbial route functions by the fundamental phenomena of electron transport chain and the microbes operate as the source of energy production utilizing the substrate. Since its initiation, microbial fuel cell has gained a lot of research focus from all over the world. The integration of waste treatment with power generation was highlighted as the most productive and sustainable part of microbial fuel cells. Over the past few decades, a lot of research and development was done on improving the design of fuel cells, searching for cost-effective electrodes and membranes for commercialization. Despite tremendous research done on this domain, its commercialization still faces a lot of hurdles especially once it comes to the overall maintenance and production cost. This chapter summarizes the basic architecture of different microbial fuel cells and the challenges that need to be addressed for making microbial fuel cells a sustainable route for the bioelectricity generation from microorganisms. Springer Nature Singapore Pte Ltd. 2020. -
Microbial Polyhydroxyalkanoates (PHAs): A Review on Biosynthesis, Properties, Fermentation Strategies and Its Prospective Applications for Sustainable Future
Exponential increase in the use and disposal of synthetic plastics has raised an alarming concern related to their adverse effect on the environment due to their recalcitrant nature and non biodegradability. Nevertheless, the depletion in the petrochemical sources made it imperative to search for other sustainable alternatives to synthetic plastics. This triggered the attention on biodegradable plastics produced from plants, animals and microbial sources that have excellent material properties like their synthetic counterparts. Polyhydroxyalkanoates (PHAs) are ineluctably promising microbial polyesters that have the competence to supersede traditional oil-based synthetic polymers which causes major disposal issues worldwide. The compostable nature, biocompatibility, thermostability, and resilience of these bio-based polymers make them an acceptable replacement in the global market. Their versatile material properties made them a propitious candidate in packaging, biomedicine, tissue engineering, biofuel production, nanocomposite formation, and other industrial applications. Despite their potential advantages, the commercialization of PHA is hindered majorly due to the high cost associated with their production and extraction. This review work majorly focuses on the production, extraction, applications and fermentation strategies for enhancing PHA production. The review also addresses the production of PHA from extremophiles, challenges associated with PHA production and sustainable substrates for PHA production using various agroindustrial wastes. 2022, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature. -
Microbial Synthesis of Alkaloids and Applications in Healthcare
Plant alkaloids are a large group of natural compounds with wide-ranging bioactive characteristics, but the number of alkaloids obtained from the plant is low. Mass extraction of these bioactive alkaloids is affected by the trouble in large-scale propagation of these plants and absence of efficient strategies for extraction. However, production by chemical reactions is a substitute method; it is less effective due to its highly complex structure. The extensive study of alkaloid biosynthesis in plants and the advancement of genetic and metabolic engineering techniques enabled the opportunity to synthesise alkaloids through microbial hosts via metabolic engineering and bioprocess optimisations. In this chapter, we discuss the various gene-manipulation strategies to produce alkaloids in various microbial hosts and their application in the healthcare industry. 2023 selection and editorial matter, Ranjna Sirohi, Amit Kumar Rai, Luciana Porto de Souza Vandenberghe, and Binod Parameswaran; individual chapters, the contributors -
Microcannular electrode/polymer electrolyte interface for high performance supercapacitor
In the present work, the ionic resistance in the activated carbon (AC) electrode and blend polymer electrolyte (BPE) interface is reduced by tuning binder and BPE. A unique microcannulars channel connecting AC, binder and gaur gum (GG)/polyvinylalcohol (PVA) electrolyte is developed for easy Li+ movement. The use of AC derived from areca nut and natural GG as a binder makes the developed method more environmentally sustainable. The presence of microcannular structures on the electrode surface and BPE was confirmed using SEM and TEM analysis. Combined DSC-TGA data for BPE showed that PVA provides the mechanical support to jelly guar gum. The ionic conductivity, activation energy, dielectric studies were studied to understand the electrode/electrolyte interface mechanism. Dielectric studies revealed that the unique pathway of microcannular structures reduces the charge transfer resistance significantly at the interface. Optimized BPE was used in the fabrication of supercapacitor and specific capacitance was found to be 542 Fg-1. The time constant was 0.4 s and showed consistent cyclic pattern during galvanostatic charge/discharge studies with 99% Columbic efficiency. 2020 Elsevier Ltd -
Microfinance Sector and the Supportive Role of Regulator in its Transformation: A Case Study from India
Microfinance is a proven business model to deliver financial services to unbanked. In the beginning years of microfinance, Non-Governmental Organizations (NGOs) were engaged in microfinance initiative and used to raise capital through grants for their microfinance program, similar to other grant-based development initiatives. To become self-sustainable financial institutions, NGOs started to transform their microfinance initiatives to a for-profit legal entity. Microfinance experienced commercialization in the process of transformation which neglected the basics of microfinance, especially in protecting the interest of clients. Supportive role of regulator transformed the Indian microfinance sectors and formed sustainable financial institutions. The successful story of Reserve Bank of Indias (RBI) intervention in shaping Indian microfinance sector counters the argument of free market principle in fixing the interest rate and healthy regulation for microfinance institutions. Supportive role of Reserve Bank of India created win-win situation for both microfinance borrowers, microfinance institutions and other stakeholders for the long-term sustainability. The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2021. -
Microhardness studies of GaTe whiskers
Single crystal whiskers of gallium telluride (GaTe) have been grown by the physical vapour deposition (PVD) method. Microindentation studies were carried out on the prism faces of the needles to understand their mechanical behaviour. The variation in the microhardnessof GaTe crystals with applied load has been determined at room temperature using Vickers microhardness indenter. The work- hardening exponent has also been computed for different load regions. 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. -
Microhardness studies of vapour grown tin (II) sulfide single crystals
Earth abundant tin sulfide (SnS) has attracted considerable attention as a possible absorber material for low-cost solar cells due to its favourable optoelectronic properties. Single crystals of SnS were grown by physical vapour deposition (PVD) technique. Microindentation studies were carried out on the cleaved surfaces of the crystals to understand their mechanical behaviour. Microhardness increased initially with the load, giving sharp maximum at 15 g. Quenching effect has increased the microhardness, while annealing reduced the microhardness of grown crystals. The hardness values of as-grown, annealed and quenched samples at 15 g load are computed to be 99.69, 44.52 and 106.29 kg/mm 2 respectively. The microhardness of PVD grown crystals are high compared to CdTe, a leading low-cost PV material. The as-grown faces are found to be fracture resistant. 2015 AIP Publishing LLC. -
Microindentation Analysis of Bi2Te3 Crystals
Recent trends and advancements in materials research and technology have led to a renewed interest in the growth of crystalline solids with better physical perfection and high purity. The major emphasis of investigations has been on the growth of single crystals and the study of their physical properties suitable for device fabrication. The availability of crystals from natural resources is inadequate to meet the need of industries and also do not give sufficient variety. Although crystal growth has been the subject of absorbing interest for many years, much of the latest developments have been stimulated due to its increasing commercial importance for the fabrication of thermoelectric, optoelectric and nonlinear optical devices. Crystal has an ordered arrangement of atoms or molecules in microscopic scale and the atomic regularity shows up in the internal and external symmetry. The change in crystal shape should be brought about by the difference in controlling mechanisms of the growth dynamics. It is inevitable to investigate the relationship between the growth mechanism and resulting growth morphology. The developments in crystal technology have significant contribution to many areas of basic and applied solid state research. Industries currently rely on bulk grown crystals of a variety of materials. Hence, single crystals have been extensively studied to explore their novel physical properties and potential applications. The first chapter deals with an introduction to the crystal growth, followed by a brief history of semiconducting materials. A detailed account on the properties and applications of bismuth telluride crystals is reported. This chapter concludes with different mechanical properties and scope of the research problem. A review of literature to present theoretical knowledge on growth and characterization of bismuth telluride crystals is given in chapter 2. Chapter 3 outlines the experimental procedures and different characterization techniques used for the present work. A detailed study on the vapour and melt growth of bismuth telluride crystals and its mechanical properties is also reported. Chapter 4 is devoted to provide a detailed discussion on the results obtained from experimental research. Final chapter covers the summary and conclusions of this research work. The report ends with a reference section, listed as per the international standards. -
Microlearning and Learning Performance in Higher Education: A Post-Test Control Group Study
This study aimed at evaluating the effectiveness of microlearning in higher education. The sample consisted of first-year MBA students, and a post-test control group design was used to assess the effectiveness of a microlearning module. The results indicated that the use of microlearning was significantly related to learning performance and participants' reactions to the module. Moreover, the microlearning group scored significantly higher than the control group. The findings suggest that microlearning has the potential to improve learning outcomes and enhance participant engagement. However, the study has certain limitations, and future research is needed to gain a comprehensive understanding of the optimal design and delivery of microlearning modules. The study supports the use of microlearning in higher education as an effective instructional strategy. 2024, Commonwealth of Learning. All rights reserved. -
Micromachining process-current situation and challenges
The rapid progress in the scientific innovations and the hunt for the renewable energy increases the urge for producing the bio electronic products, solar cells, bio batteries, nano robots, MEMS, blood less surgical tools which can be possible with the aid of the micromachining. This article helps us to understand the evolution and the challenges faced by the micromachining process. Micro machining is an enabling technology that facilitates component miniaturization and improved performance characteristics. Growing demand for less weight, high accuracy, high precision, meagre lead time, reduced batch size, less human interference are the key drivers for the micromachining than the conventional machining process. Owned by the authors, published by EDP Sciences, 2015.