Enrichment of linear hexahedral finite elements using rotations of a virtual space fiber

The present paper deals with the enrichment of 3D low‐order finite elements. The used concept is based on the idea that a 3D virtual fiber, after a spatial rotation, introduces an enhancement of the strain field tensor approximation. A consistent stiffness matrix is obtained, allowing a better approximation of the actual solution compared with that resulting from low‐order finite elements. Implemented for two eight‐node hexahedral elements, the performance of the space fiber rotation concept is assessed by running some classical beam, plate, and shell benchmarks, and the obtained results are compared especially with those given by linear eight‐node and quadratic 20‐node hexahedral elements. In particular, it is shown that the developed elements accuracy is significantly superior to that of the classical eight‐node hexahedral element and close to that of the classical 20‐node hexahedral element. Copyright © 2013 John Wiley & Sons, Ltd.     

Relation between fabric porosity and vacuum extraction efficiency: Energy issues

Vacuum extraction is a technique that removes the unbound water from the fabrics by the help of air flow through the fabrics at high velocities. Air flow through textile fabrics is mainly affected by the fabric structure such as tightness, porosity and air permeability. This paper outlines the effects of the fabric structure on the vacuum drying efficiency. Thirty woven fabrics with different porosities were dried by vacuum extraction method, and it was found that the lower the porosity or the lower the air permeability, the higher the water removal effects and energy requirement.     

Fabrication and electrochemical characterization of a vertical array of MnO2 nanowires grown on silicon substrates as a cathode material for lithium rechargeable batteries

A complementary metal-oxide-semiconductor (CMOS) compatible process for fabricating on-chip microbatteries based on nanostructures has been developed by growing manganese dioxide nanowires on silicon dioxide (SiO₂)/silicon (Si) substrate as a cathode material for lithium rechargeable batteries. High aspect-ratio anodized aluminum oxide (AAO) template integrated on SiO₂/Si substrates can be exploited for fabrication of a vertical array of nanowires having high surface area. The electrolytic manganese dioxide (EMD) nanowires are galvanostatically synthesized by direct current (dc) electrodeposition. The microstructure of these nanowire arrays is investigated by scanning electron microscopy and X-ray diffraction. Their electrochemical tests show that the discharge capacity of about 150 mAh g⁻¹ is maintained during a few cycles at the high discharge/charge rate of 300 mA g⁻¹.     

Time-aware selection approach for service composition based on pruning and improvement techniques

Software Quality Journal - In service-oriented environments, abstract business processes can be implemented by concrete services to build complex applications. Given global user constraints,...     

The SemSPM approach: fine integration of WS-SecurityPolicy semantics to enhance matching security policies in SOA

The lack of semantics in WS-SecurityPolicy standard hampers the effectiveness of matching security policies. To resolve this problem, we present a semantic approach for matching Web service security policies. The approach consists in the transformation of WS-SP into an OWL-DL ontology and the definition of a set of rules which automatically generate semantic relations that can exist between the provider and requestor security requirements. We show how these relations lead to more correct and refined matching of security policies. We also describe the implementation details of our approach and its validation through a real-world use case.     

A new approach for estimation of obstructive sleep apnea syndrome

Obstructive sleep apnea syndrome (OSAS) is a situation where repeatedly upper airway stops off while the respiratory effort continues during sleep at least for 10 s. Apart from polysomnography, many researchers have concentrated on exploring alternative methods for OSAS detection. However, not much work has been done on using non-Gaussian and nonlinear behavior of the electroencephalogram (EEG) signals. Bispectral analysis is an advanced signal processing technique particularly used for exhibiting quadratic phase-coupling that may arise between signal components with different frequencies. From this perspective, in this study, a new technique for recognizing patients with OSAS was introduced using bispectral characteristics of EEG signal and an artificial neural network (ANN). The amount of Quadratic phase coupling (QPC) in each subband of EEG (namely; delta, theta, alpha, beta and gamma) was calculated over bispectral density of EEG. Then, these QPCs were fed to the input of the designed ANN. The neural network was configured with two outputs: one for OSAS and one for estimation of normal situation. With this technique a global accuracy of 96.15% was achieved. The proposed technique could be used in designing automatic OSAS identification systems which will improve medical service.     

Stoppage of light made flexible by an additional control field

Abstract

We show how the application of a coupling field connecting the two lower metastable states of a lambda system facilitates stoppage of light in a coherently driven Doppler-broadened atomic medium via electromagnetically induced transparency.     

Assessment of finishing processes by exhaustion principle for textile fabrics: An exergetic approach

This study reveals the exergetic assessment of exhaustion processes for textile fabrics using actual operational data. The objective of the current work is to address the effects of the exhaust method parameters on exergy destruction and consumption rates. Additionally, a case study for cotton and polyester finishing processes was performed. The process temperature and time, water inlet temperature and liquor ratio were found to be the main parameters that affect exergy destruction rates. The effects of carry-over on exergy destruction rates were also investigated. It was shown that, 23% and 50% of total exergy destruction rate were occurred by the bleaching and the washing steps for cotton finishing, respectively, while 32% of total was accounted for the dyeing step of polyester finishing. The exergy efficiency of the finishing processes was obtained to be between 4.6% and 34.8% depending on the process variables. High temperature processes had higher exergy efficiency values.     

Looking-In and Looking-Out of a Vehicle: Computer-Vision-Based Enhanced Vehicle Safety

This paper presents investigations into the role of computer-vision technology in developing safer automobiles. We consider vision systems, which cannot only look out of the vehicle to detect and track roads and avoid hitting obstacles or pedestrians but simultaneously look inside the vehicle to monitor the attentiveness of the driver and even predict her intentions. In this paper, a systems-oriented framework for developing computer-vision technology for safer automobiles is presented. We will consider three main components of the system: environment, vehicle, and driver. We will discuss various issues and ideas for developing models for these main components as well as activities associated with the complex task of safe driving. This paper includes a discussion of novel sensory systems and algorithms for capturing not only the dynamic surround information of the vehicle but also the state, intent, and activity patterns of drivers     

Causality in propagation of a pulse in a nonlinear dispersive medium

We investigate the causal propagation of the pulse through dispersive media by very precise numerical solution of the coupled Maxwell–Bloch equations without any approximations about the strength of the input field. We study full nonlinear behaviour of the pulse propagation through solid state media like ruby and alexandrite. We have demonstrated that the information carried by the discontinuity, i.e. front of the pulse, moves inside the media with velocity c even though the peak of the pulse can travel either with sub-luminal or with super-luminal velocity. Our numerical demonstration is subject to the condition that the background refractive index of the medium is unity. We extend the argument of Levi-Civita to prove that the discontinuity would travel with velocity c even in a nonlinear medium.