Dissipative heat for the Casson fluid flow past an expanding cylindrical surface

A non-Newtonian model is developed by considering the flow of non-Newtonian Casson fluid past an expanding cylinder embedded in a porous medium. The novelty arises because of the conjunction of dissipative heat, and the additional heat source that enriches the heat transport phenomenon significantly. The application of the study is vital due to the flow of blood through the artery, a physiological study. Therefore, the study of Casson fluid plays an important role. The nonlinear partial differential equations that appeared in the formulation are now renovated to the coupled nonlinear ordinary differential equations. However, a numerical technique associated with shooting-based followed by Runge–Kutta fourth-order is employed for the solution of these transformed equations. The uniqueness of diverse pertinent parameters on the flow phenomena is scrutinized through graphs and numerically simulated results presented in tables. The important observations are as follows; the magnetic parameter and permeability augment the shear rate coefficients, whereas the Casson parameter rendered the opposite impact. Furthermore, the non-Newtonian Casson parameter retards the fluid temperature, and the curvature parameter significantly enhances it.     

Corrosion of Borosilicate Glasses Subjected to Aggressive Test Conditions: Structural Investigations

Sodium borosilicate (NBS) and barium sodium borosilicate (BBS) glasses, used for immobilization of high‐level nuclear waste with compositions (SiO₂)_0.477(B₂O₃)_0.239(Na₂O)_0.170(TiO₂)_0.023(CaO)_0.068(Al₂O₃)_0.023 and (SiO₂)_0.482(B₂O₃)_0.244(Na₂O)_0.220(BaO)_0.054 were subjected leaching experiments under hydrothermal conditions in an autoclave at 200°C for different time durations. Morphological and structural transformations associated with leaching, have been monitored with techniques like XRD, SEM, solid‐state nuclear magnetic resonance. XRD and SEM along with NMR studies have confirmed that, upon leaching, formation of an aluminosilicate phase, Zeolite‐P (Na₆Al₆Si₁₀O₃₂·12H₂O), occurs with NBS glass. BBS glass upon subjecting to the same conditions leads to formation of multiple amorphous phases having Q⁴ (silica rich phase) and Q³ structural units of Silicon along with structurally modified residual glass. Upon leaching BO₃ structural units preferentially get released from BBS glass. Comparison of results with international simple glass confirmed that, for the latter, mass loss rates are one order of magnitude lower.     

Implementation of complex digital PLL for phase detection in software defined radar

Software defined radar (SDR) has been the latest trend in developing enhanced radar signal processing techniques for state-of-the-art radar systems. SDR provides tremendous flexibility in reconfigurable design and rapid prototyping capabilities on FPGA platform. To cater real-time processing for high-speed radar, COordinate Rotation Digital Computer (CORDIC) unit has been utilized as a core processing element in a complex digital phase locked loop (DPLL) for digital demodulation of received signal. Since the real-time systems are required to handle extremely high sampling rates, the pipelined architecture of CORDIC processing element has been chosen for its inherent high system throughput. The architecture is optimized in terms of bit-length for better convergence and loop performance of the first order complex DPLL during demodulation. TheBOXCARfilter has been used as a low pass filter in the output stage of the detector for better information recovery from narrow samples with little energy signal without incurring hardware overhead. Extensive MATLAB simulations have been added to show the effectiveness of the design for the application of radar phase detection.     

Design and simulation of a solar–wind–biogas hybrid system architecture using HOMER in India

The renewable energy sources are accompanied by certain constraints as reliability, availability and continuous generation. In India, biomass is considered as the second best suitable combination with other renewable energy sources. Both solar and wind are undependable renewable energies as they are unpredictable. Now the key to successful renewable energy harvesting lies in the selection of hybrid system architecture for power generation. In rural areas, light is usually unavailable and if it does, it is mostly an incandescent light used for household lighting instead of fluorescent. System reliability, economy and environmental issues are the three major issues for decentralised electrification. So, finding the best suited hybrid system configuration to overcome these constraints is the need of the hour. It is at this stage that HOMER comes into the picture. HOMER, abbreviated name of hybrid optimization model for electric renewable, successfully realises system configuration before its installation and works for on-grid, off-grid and stand-alone systems, which make it useful for rural to urban applications. It simulates and optimises the best suitable solution for a hybrid system and generates reports incorporating all the aspects in designing a system. Here, a typical hybrid system is considered and the implementation of HOMER software has been incorporated.     

Dynamical Evolution of Wear Particles in Nanocontacts

Nanoscale surface modification, by the interaction of sliding surfaces and mobile nanoparticles, is a critical parameter for controlling friction, wear and failure of surface structures. Here we demonstrate how nanoparticles form and interact in real-time at moving nanocontacts, with reciprocating wear tests imaged in situ at the nanoscale over >300 cycles in a transmission electron microscope. Between sliding surfaces, friction-formed nanoparticles are observed with rolling, sliding and spinning motions, dependant on localised contact conditions and particle geometry. Over periods of many scratch cycles, nanoparticles dynamically agglomerate into elongated clusters, and dissociate into smaller particulates. We also show that the onset of rolling motion of these particles accompanies a reduction in measured friction. Introduction of nanoparticles with optimum shape and property can thus be used to control friction and wear in microdevices.     

A new class of PANI-Ag core-shell nanorods with sensing dimensions

A single-step, cost-effective and eco-safe synthesis of a new class of homogeneous silver-polyaniline (PANI-Ag) core-shell nanorods is carried out via mild photolysis by ultraviolet radiation from sunlight (SUN UV-radiation). X-ray diffraction (XRD) of these core-shell nanorods gives two additional peaks from PANI centered at 2θ = 20.5° and 24. 9°. A validation of the core-shell structural information is given by transmission electron spectroscopy (TEM) whereas the tubular shape morphology is determined by scanning electron microscopy (SEM). UV-Vis. absorption shows a strong blue-shift along with photoluminescence emission. Fourier transform-infrared spectroscopy (FT-IR) and energy dispersive X-ray spectroscopy (EDX) also support the core-shell formation. Thermogravimetric analysis (TGA) shows good thermal stability and allows excellent detection of hydrogen peroxide and hydrazine. The cyclic voltammetry (CV) results show excellent electro-activation, indicating its promising potential in sensing of clinical and environmental analytes.     

Changes During Accelerated Storage in Millet–Wheat Composite Flours for Bread

Two millet–wheat composite flours, CF1 and CF2, were formulated based on the rheological and textural properties of dough using response surface methodology. The optimized contents of composite flour CF1 were 61.8% barnyard millet flour, 31.4% wheat flour, and 6.8% gluten, respectively. The optimized components of the composite flour CF2 were barnyard millet flour 9.1%, finger millet flour 10.1%, proso millet flour 10.2%, and wheat flour 70.6%. Millet–wheat composite flours were stored in three different packaging materials, namely, low-density polyethylene (LDPE), high-density polyethylene (HDPE), and metallized polyester (MP), at 90% RH and 40 °C temperature for 90 days. For the packaging of millet–wheat composite flour CF1, MP was found best among the tested packaging materials, where moisture gain in samples was minimum (55%) as compared with materials LDPE (124%) and HDPE (100%). Vitamin loss among the different packaging materials was not significantly different at the 5% level of significance. The shelf lives of the composite flours were estimated based on their critical moisture contents. After 90 days of storage of CF1, the highest retention of starch (91.85%) was recorded in MP packaging followed by HDPE (87.5%) and LDPE (84.8%). However, in CF2, the retention was not significant in all three packaging materials (P?相似文献   

SOLVOLYTIC EXTRACTION OF ASSAM COAL IN DIFFERENT ALKENES UNDER AMBIENT PRESSURE CONDITIONS

ABSTRACT

Assam coal has been extracted with octene-1, decene-1. dodecene-1, tetradecene-1 and cetene-1 respectively-at. their boiling points. More than 50% coal was extracted using cetene-1 as a solvent and the residual coal obtained was rendered further extractable in quinoline up to 39% extent. Thus, more than 707% coal was rendered extractable in cetene-1 followed by quinoline extraction. This was more than that observed through the successive extractions in anthracene as followed by quinoline extraction (60%). These studies showed alkenes to be very promising for the extraction of coal for industrial operations, as these are coal and petroleum derived solvents.     

Capacities-based supply chain network design considering demand uncertainty using two-stage stochastic programming

The design of a supply chain (SC) aims to minimize cost so the product can reach the customer at the cheapest cost with flexible demand. The demand of a product is variable with time and environment. Most of the researchers have considered investment cost, processing cost, and transportation cost as variable costs to minimize the cost while considering a constant demand. In actual practice, the demands are flexible. In this paper, a two-stage stochastic programming model has been proposed for a capacities-based network design of a supply chain for flexible demands while considering inventory carrying cost and missed opportunity cost in addition to the above-mentioned costs. It will enhance the logistic planning and seek the location network optimally. Furthermore, in the first stage, decision variables represent different nodes (facility locations of echelons) of the supply chain, with the assumption that they will be considered at the design stage before uncertain parameters are unveiled. On the other hand, decision variables related to the amount of products to be produced and stored in the nodes of the SC, the flows of materials among the entities of the network, and shortfalls and excess at the customer centers are considered as second-stage variables. The methodology has been illustrated by solving an example. It was found that the proposed model yields more feasible and advantageous results.     

Prediction of Adulteration in Honey Using Rheological Parameters

Honey is a sweet substance that can be adulterated easily with inexpensive sweeteners by making syrup. Water being the second major constituent of honey, makes its flow behavior one of the important parameter for quality determination. In the present study, the rheological characteristics of honey samples adulterated with different concentrations of jaggery syrup were studied using rotational rheometer with parallel plate geometry. The viscosity of honey and adulterated honey samples was determined by varying temperature and percentage of jaggery concentration. All the adulterated honey samples behaved as non-Newtonian fluid. The viscosity increased linearly with increase in concentration of adulteration and varied from 2.48–4.80 Pa s as adulteration increased from 5 to 30%. Oscillatory tests were performed to find the possible effect of storage time on different honey samples. It was found that adulteration decreased the shelf life of honey, thus rheology can be considered one of the important parameters to determine adulteration of honey.