Induced EM fields inside human bodies irradiated by EM waves of up to 500 MHz.

In this paper, the internal EM field and the specific absorption rate of EM energy induced inside human bodies by EM waves of up to 500 MHz are theoretically quantified based on a tensor integral equation method. Numerical results for a realistic model of a man of 177 cm high irradiated by EM waves of various frequencies and of vertical and horizontal polarizations are presented. The resonance phenomenon and the effect of body heterogeneity on the induced field are studied. Some theoretical results are compared with existing experimental results.     

Nonlinear material behaviour and failure of closed-cell polymer foams

Classical strength criteria, like the von Mises criterion, are used to postulate the failure of ductile materials like steel or brass. It is known that for the application of foams in modern lightweight structures extended criteria are required, since foams are sensitive to hydrostatic stress. This observation on the macroscale can be explained by the deformation mechanisms of one single foam cell. Under hydrostatic stress, the deformation of the cell causes a non-uniform stress state of the cell walls. To understand the mechanism on the microlevel, a finite element model on the basis of a tetrakaidecahedron as unit cell was implemented. Utilising a strain energy-based homogenisation concept, the effective properties of the foam can be obtained. To adapt the geometric properties of the model to the real microstructure of the foam, results of a computer tomography image analysis were used by considering several imperfections in the cell geometry. For the analysis of the stress state on the microlevel, different load cases were applied to the unit cell. By means of these simulations, the geometrically nonlinear stress–strain curves on the macrolevel were deduced. Furthermore, the analysis of the finite element model provides an insight into the deformation mechanism on the microscale and allows the prediction of failure as well. Finally, the predicted failure points are represented in the Burzyński plane and compared with experimental results. The current paper focuses on the hard foam ROHACELL\({^{\circledR}}\) IG-series (industrial grade), which is a closed-cell PMI foam produced by Evonik Industries AG, Germany.     

Treatment of Acidic Groundwater in Acid Sulfate Soil Terrain Using Recycled Concrete: Column Experiments

Acidic groundwater generated from pyrite oxidation in acid sulfate (AS) soil is a major geoenvironmental problem in Australia. This study aims to evaluate recycled concrete as a reactive material in permeable reactive barriers (PRBs) for the remediation of acidic groundwater in low-lying AS soil floodplains. Laboratory experiments were systematically conducted to investigate the acid neutralization behavior of recycled concrete and its potential to remove dissolved Al and Fe. The results confirmed that recycled concrete could effectively treat acidic groundwater from an AS soil terrain, resulting in near neutral effluent over a long period with complete removal of Al and Fe. The major mechanisms involved in neutralizing acidic groundwater are thought to be the precipitation of Al and Fe as oxides, oxyhydroxides, and hydroxides. However, the accumulation of secondary minerals could decrease the reactivity of the recycled concrete. For example, chemical armoring could decrease the neutralizing capacity of recycled concrete by up to 50% compared with the theoretical acid neutralization capacity of this material. The results reported here also show that the neutralization capacity and reactive efficiency of recycled concrete are dependent on the initial pH value and also the concentration of Al and Fe in acidic groundwater.     

Online Signature Verification and Recognition: An Approach Based on Symbolic Representation

In this paper, we propose a new method of representing on-line signatures by interval valued symbolic features. Global features of on-line signatures are used to form an interval valued feature vectors. Methods for signature verification and recognition based on the symbolic representation are also proposed. We exploit the notions of writer dependent threshold and introduce the concept of feature dependent threshold to achieve a significant reduction in equal error rate. Several experiments are conducted to demonstrate the ability of the proposed scheme in discriminating the genuine signatures from the forgeries. We investigate the feasibility of the proposed representation scheme for signature verification and also signature recognition using all 16500 signatures from 330 individuals of the MCYT bimodal biometric database. Further, extensive experimentations are conducted to evaluate the performance of the proposed methods by projecting features onto Eigenspace and Fisherspace. Unlike other existing signature verification methods, the proposed method is simple and efficient. The results of the experimentations reveal that the proposed scheme outperforms several other existing verification methods including the state-of-the-art method for signature verification.     

Shape reanalysis and sensitivities utilizing preconditioned iterative boundary solvers

The computational advantages associated with the utilization of preconditioned iterative equation solvers are quantified for the reanalysis of perturbed shapes using continuum structural boundary element analysis (BEA). Both single- and multizone three-dimensional problems are examined. Significant redutions in computer time are obtained by making use of previously computed solution vectors and preconditioners in subsequent analyses. The effectiveness of this technique is demonstrated for the computation of shape response sensitivities required in shape optimization. Computer times and accuracies achieved using the preconditioned iterative solvers are compared with those obtained via direct solvers and implicit differentiation of the boundary integral equations. It is concluded that this approach employing preconditioned iterative equation solvers in reanalysis and sensitivity analysis can be competitive with if not superior to those involving direct solvers.     

Effect of 1-D silver grated electrode on wafer‐based TOPCon c-Si solar cell

Silicon - A modified structure of Anti reflection coating (ARC) less wafer based 200 μm thick c-Si Solar cell with tunnel oxide passivated contact (TOPCon) solar cell is proposed with...     

Junctionless Silicon Nanotube TFET for Improved DC and Radio Frequency Performance

Silicon - In this work, a junctionless silicon nanotube TFET (JL-SiNT-TFET) is reported for low standby power and high-frequency applications. The workfunction of the core gate (CG) metal is...     

Assessment of exposed elements in a changing built environment by using an integrated model of debris flow initiation and runout (Kalimpong region,Himalaya)

Bulletin of Engineering Geology and the Environment - The impact of debris flow is not only limited to the source area but it is also significantly governed by the runout. It is evident in many...     

Silver ferrite and cobalt ferrite dispersed castor oil polyurethane nanocomposites: Quenching studies of bovine serum albumin

The use of renewable resource is a strategic opportunity to meet growing demands of eco-friendly materials. The present study reports the synthesis of castor-oil-based polyurethane (COPU), and its nanocomposites with CoFe₂O₄ and AgFeO₂ via sonication technique. Formation of the nanocomposite was confirmed by IR analysis while UV–visible studies revealed encapsulation of the ferrite particles by COPU. The interaction between COPU, AgFeO₂, CoFe₂O₄, and their nanocomposites with bovine serum albumin (BSA) was also investigated by fluorescence spectroscopy which revealed static quenching of BSA through complex formation. The quenching rate for COPU was determined to be 1.98?×?10⁴?LM^?1 while for pure CoFe₂O₄ and AgFeO₂, it was found to be 3?×?10⁴?LM^?1 and 3.2?×?10⁴?LM^?1, respectively. The interaction of BSA particularly with silver and cobalt ferrite nanoparticles within COPU matrix was found to be promising. It was found that by controlling the loading of ferrite in COPU matrix, desired binding could be achieved.     

Segmented Drain Engineered Tunnel Field Effect Transistor for Suppression of Ambipolarity

Silicon - In this paper, a new Si0.6Ge0.4/Si heterostructure tunneling field-effect transistor with segmented drain (SiGe/Si SD TFET) is proposed and simulated by Silvaco ATLAS simulator. The drain...