Energy and exergy analyses of an integrated biomass gasification combined cycle employing solid oxide fuel cell and organic Rankine cycle

In this study, an advanced combined cycle-based power generation system, integrating biomass gasification with a solid oxide fuel cell (SOFC) module and an organic vapor turbine, has been modeled and analyzed. The thermodynamic model has been developed by integrating the component models through customized codes written using engineering equation solver software. Both energetic and exergetic analyses of the proposed system have been conducted under varying design and operating parameters to assess their effects on the performance of the proposed system. The study reveals that the integrated system yields a maximum overall energetic efficiency of 41.13%, occurring at a pressure ratio of 2.5 for the compressor. The gasifier is the component responsible for maximum exergy destruction (accounting for 32.36% of fuel exergy input), followed by the heat recovery vapor generator and the SOFC.     

Granular micromechanics model of anisotropic elasticity derived from Gibbs potential

This paper presents a Gibbs potential-based granular micromechanics approach capable of modelingmaterialswith complete anisotropy. The deformation energy of each grain–pair interaction is taken as a functionof the inter-granular forces. The overall classical Gibbs potential of a material point is then defined as thevolume average of the grain–pair deformation energy. As a first-order theory, the inter-granular forces arerelated to the Cauchy stress tensor using a modified static constraint that incorporates directional distributionof the grain–pair interactions. Further considering the conjugate relationship of the macroscale strain tensorand the Cauchy stress, a relationship between inter-granular displacement and the strain tensor is derived.To establish the constitutive relation, the inter-granular stiffness coefficients are introduced considering theconjugate relation of inter-granular displacement and forces. Notably, the inter-granular stiffness introducedin this manner is by definition different from that of the isolated grain–pair interactive. The integral formof the constitutive relation is then obtained by defining two directional density distribution functions; onerelated to the average grain–scale combined mechanical–geometrical properties and the other related to purelygeometrical properties. Finally, as the main contribution of this paper, the distribution density function isparameterized using spherical harmonics expansion with carefully selected terms that has the capability ofmodeling completely anisotropic (triclinic) materials. By systematic modification of this distribution function,different elastic symmetries ranging from isotropic to completely anisotropic (triclinic) materials are modeled.As a comparison, we discuss the results of the present method with those obtained using a kinematic assumptionfor the case of isotropy and transverse isotropy, wherein it is found that the velocity of surface quasi-shearwaves can show different trends for the two methods.     

Outdoor Path Loss Predictions Based on Extreme Learning Machine

Wireless Personal Communications - In a typical outdoor environment, the propagation of radio waves is usually random in nature, to the extent that the characterization of the wireless...     

Surface ultrastructure of larval mouthpart sensilla of the muga silkmoth,Antheraea assamensis,an endemic species of North‐East India

Scanning electron microscopy of different larval stages of the muga silk moth Antheraea assamensis revealed the presence of sensilla chaetica, sensilla trichoidea, sensilla styloconica, gustatory sensilla, sensory pegs, placoid sensilla, etc., on their mouth parts. Some variations were observed in the number and sub‐types of sensilla in certain larval stages indicating some differences in sensitivity of the worms in different instars to the food plant and microhabitat. Microsc. Res. Tech., 2010. © 2010 Wiley‐Liss, Inc.     

Crystallography of Interfaces and Grain Size Distributions in Sr‐Doped LaMnO3

Grain‐boundary plane distributions (GBPDs), grain size distribution (GSDs), and upper tail departure from log‐normal GSDs were quantified in dense and porous La_0.8Sr_0.2MnO₃ samples to understand expected microstructures in solid oxide fuel cells. Samples were sintered at 1450°C for 4 h and then annealed between 800°C and 1450°C. The GBPDs and normalized GSDs reached steady state during sintering and little variation occurred during annealing. The GBPDs were nearly isotropic, with the relative areas of {001} planes being slightly higher than random (and the relative areas of {111} planes being less than random). The porous sample had an almost identical GBPD, whereas the almost isotropic pore boundary plane distribution was essentially opposite to the GBPD. The upper tails of the experimental GSDs, and several theoretical distributions, were characterized using peaks‐over‐threshold analysis. Dense samples, and all normal grain growth models, exhibit lower frequencies of large grains in the upper tail than would a log‐normal distribution, and the experimental distributions are similar to the Mullins distribution. Porous samples, however, have an anomalous increased frequency of large grains in the upper tail, as compared to all the model distributions, even though other metrics of the microstructure indicate the dense and porous systems are similar.     

Mechanical characteristics of glass fibre reinforced polymer made of furfuryl alcohol bio-resin

Conventional fiber reinforced polymers (FRPs) require polymers such as epoxies that are not biodegradable, which have a significant impact on the environment. This study aims at replacing conventional polymers with bio-polymers which are more sustainable. The study investigates the tensile mechanical properties of glass-FRP (GFRP) laminates fabricated by wet layup using two types of organic furfuryl alcohol bio-resins extracted renewable resources, such as corncobs. Results are compared to control specimens fabricated using conventional epoxy resin. The study investigates the effects of catalyst type and dosage as well as the curing time on the tensile strength and modulus of the GFRP. The study also investigates the optimal overlap splice of the laminates. It was shown that by careful selection of viscosity of bio-resin, and type and dosage of catalyst similar mechanical properties to epoxy-GFRP can be achieved. The optimal catalyst proportion was 3 % by weight. Full strength occurred after 13 days curing but 84 % occurred in 2 days. The optimal lap splice length was 200 mm, however, the maximum strength was only 68 % of the full ultimate tensile strength as bond failure always governs at the splice.     

Ant Colony Optimization Based Sub-channel Allocation Algorithm for Small Cell HetNets

Two-tier heterogeneous networks (HetNets) composed of a conventional macrocellular network and small cell networks (SCNs) have been proposed in the literature with the aim to extend indoor coverage and realize efficient radio resource usage. As SCN shares the same frequency band with the underlying macrocell, the cross tier interference needs to be mitigated since the inter-SCN and cross tier interference at the SCN boundary may result in undesirable network performance degradation. In this paper, we propose an intelligent physical resource block (PRB) allocation as a solution to mitigate the downlink intra-SCN interference as well as the inter-tier interference in OFDM-based systems. The allocation of the PRBs to the network users is formulated as a graph coloring problem, and solved using an ant colony optimization (ACO)-based approach. Simulation results are provided, showing that our ACO-based algorithm outperforms the Received Power-based Allocation (RPA) and Received SINR-based Allocation (RSA) algorithms in terms of average SINR experienced by network users, outage probability, and number of required PRBs.     

Lightweight Localization Using Trilateration for Sensor Networks

Localization is an unavoidable procedure in location aware sensor networks. In such networks, management of a large amount of location information along with its processing and updating is highly desirable at a central station of the network. In this paper, we have discussed the implementation of software layer to be run on various types of sensor nodes in the localization network, which has been dealt with extensively along with some of the addressed problems and their respective solutions. In addition, the article discusses implementation of an already mathematical formulation of least squares trilateration, which has not yet been attempted in the space of wireless sensor networks. To support our clam we performed experimental analysis on \(telosb\) motes. Experimental results of proposed framework shows that average error with respect to the physical location estimation can be reduced upto 46.66 % using 4 anchor node as compare to three anchor nodes at outdoor scenario and upto 40 % in indoor scenario.