A remotely-powered, 20 Mb/s, 5.35 pJ/bit impulse-UWB WSN tag for cm-accurate-localization sensor networks

This paper presents an ultra-low-power, low-voltage sensor node for wireless sensor networks. The node scavenges RF energy out of the environment, resulting in a limited available power budget and causing an unstable supply voltage. Hence, accurate and extensive power management is needed to achieve proper functionality. The fully integrated, autonomous system is described, including the scavenging circuitry with integrated antenna, the power detection and power control circuits, the on-chip clock reference, the UWB transmitter and the digital control circuitry. The wireless sensor node is implemented in \(0.13 \,\upmu \hbox {m}\) CMOS technology. The only external components are a storage capacitor and a UWB transmit antenna. The system consumes only \(113\, \upmu \hbox {W}\) during burst mode, while only 8 nW is consumed during the scavenging operation, enabling an efficiency of 5.35 pJ/bit which is significantly better than current state-of-the-art UWB tags. Due to the use of impulse-radio UWB, also cm-accurate localization of the tag can be achieved.     

Crack analysis in orthotropic media using the extended finite element method

An extended finite element method has been proposed for modeling crack in orthotropic media. To achieve this aim a discontinuous function and two-dimensional asymptotic crack-tip displacement fields are used in a classical finite element approximation enriched with the framework of partition of unity. It allows modeling crack by standard finite element method without explicitly defining and re-meshing of surfaces of the crack. In this study, fracture properties of the models are defined by the mixed-mode stress intensity factors (SIFs), which are obtained by means of the domain form of the interaction integral (M-integral). Numerical simulations are performed to verify the approach, and the accuracy of the results is discussed by comparison with other numerical or (semi-) analytical methods.     

Divided-wall distillation column design using molecular tracking

Divided-wall column (DWC) is an intensified separation process and so far developing a simple procedure for designing these units has been challenging. In this work, the concept of molecular tracking has been integrated with conventional methods to build a simple and easy-to-use methodology for designing DWCs for multicomponent separations. Application of the proposed approach is highlighted through several three- and four-component mixtures. The configuration obtained using molecular tracking gives a design with lower energy demands for the column reboiler, compared to other design methodology, which directly impacts the OPEX of the system.     

Reproducible segmentation of white matter hyperintensities using a new statistical definition

Objectives

We present a method based on a proposed statistical definition of white matter hyperintensities (WMH), which can work with any combination of conventional magnetic resonance (MR) sequences without depending on manually delineated samples.

Materials and methods

T1-weighted, T2-weighted, FLAIR, and PD sequences acquired at 1.5 Tesla from 119 subjects from the Kings Health Partners-Dementia Case Register (healthy controls, mild cognitive impairment, Alzheimer’s disease) were used. The segmentation was performed using a proposed definition for WMH based on the one-tailed Kolmogorov–Smirnov test.

Results

The presented method was verified, given all possible combinations of input sequences, against manual segmentations and a high similarity (Dice 0.85–0.91) was observed. Comparing segmentations with different input sequences to one another also yielded a high similarity (Dice 0.83–0.94) that exceeded intra-rater similarity (Dice 0.75–0.91). We compared the results with those of other available methods and showed that the segmentation based on the proposed definition has better accuracy and reproducibility in the test dataset used.

Conclusion

Overall, the presented definition is shown to produce accurate results with higher reproducibility than manual delineation. This approach can be an alternative to other manual or automatic methods not only because of its accuracy, but also due to its good reproducibility.

     

Recent progress in MoS2 for solar energy conversion applications

In an era of graphene-based nanomaterials as the most widely studied two-dimensional (2D) materials for enhanced performance of devices and systems in solar energy conversion applications, molybdenum disulfide (MoS₂) stands out as a promising alternative 2D material with excellent properties. This review first examined various methods for MoS₂ synthesis. It, then, summarized the unique structure and properties of MoS₂ nanosheets. Finally, it presented the latest advances in the use of MoS₂ nanosheets for important solar energy applications, including solar thermal water purification, photocatalytic process, and photoelectrocatalytic process.     

Local RBF-DQ method for two-dimensional transient heat conduction problems

The meshless local radial basis function-based differential quadrature (RBF-DQ) method is applied on two-dimensional heat conduction for different irregular geometries. This method is the combination of differential quadrature approximation of derivatives and function approximation of radial basis function. Four different geometries with regular and irregular boundaries are considered, and numerical results are compared with those gained by finite element (FE) solution achieved by COMSOL commercial code. Outcomes prove that current technique is in very good agreement with FEM and this fact that RBF-DQ method is an accurate and flexible method in solution of heat conduction problems.     

Chemical composition and antiaflatoxigenic activity of Carum carvi L., Thymus vulgaris and Citrus aurantifolia essential oils

In order to find out plants useful to controlling aflatoxins (AFs) production, the essential oils (EOs) from 12 medicinal plants prepared by hydrodistillation were studied with special reference to the inhibition of Aspergillus parasiticus growth and AFs production. The toxigenic fungus was cultured in presence of various oils in 6-well microplates using a microbioassay technique. The mycelial mass was estimated as an index of fungal growth, while the aflatoxins B₁ (AFB₁) and G₁ (AFG₁) were measured by high performance liquid chromatography (HPLC). Among plants tested, Thymus vulgari and Citrus aurantifolia were found to inhibit both A. parasiticus and AF production. The EOs from Mentha spicata L., Foeniculum miller, Azadirachta indica A. Juss, Conium maculatum and Artemisia dracunculus were only inhibited fungal growth, while Carum carvi L. effectively inhibited AF production without any obvious effect on fungal growth. The other plants including Ferula gummosa, Citrus sinensis, Mentha longifolia and Eucalyptus camaldulensis had no effect on A. parasiticus growth and AF production at all concentrations used. The IC₅₀ values of T. vulgaris, C. aurantifolia and C. carvi for AF inhibition were reported as 93.5, 285.6, and 621.9 μg/ml for AFB₁, while they were calculated as 11.7, 50.1, and 56.0 μg/ml for AFG₁. These results indicate that the EOs of some medicinal plants may be considered as potential candidates to protect foods and feeds from toxigenic fungus growth and subsequent AF contamination.     

Effects of variations of voltage and pH value on the shear strength of soil and durability of different electrodes and piles during electrokinetic phenomenon

Electrokinetic(EK)treatment is an effective method in accelerating the consolidation and improving the geotechnical properties of fine-grained soils.This method...     

Optimized design procedure for coupling panels in steel plate shear walls

Coupling beams have had a widespread application as performance enhancing devices within concrete structures and more recently also in steel structures. However, the conventional coupling beams are not so efficient in coupling distant walls. In this paper, a novel form of coupling members, namely, coupling panels is proposed and, then, the application for a nine‐story building is investigated. Coupling panels are steel plates which are exerted in the intermediate spans between adjacent shear walls and act as a mega‐coupling beam. First, a verified finite element model is constructed to demonstrate coupling panel behavior along with its global structural mechanism. Subsequently, a nine story building is designed and retrofitted as a new and existing building, using coupling panels. Moreover, an innovative optimization algorithm is proposed in order to achieve the best plate configuration to improve the structural performance using Nonlinear Static Analysis, Modal Pushover Analysis and Time History Analysis and the corresponding results are compared. In summary, it is shown that coupling panels can considerably control structural deformation demands toward a uniform pattern and reduce demands of main shear walls. The optimized design method also leads to a more economical design in comparison with force‐based design approaches. In addition, the proposed coupling panels are shown to be significantly effective, regarding to energy dissipation during earthquakes, and can enhance the structural resiliency. Copyright © 2016 John Wiley & Sons, Ltd.     

A Reinforcement Learning Based Routing in Cognitive Radio Networks for Primary Users with Multi-stage Periodicity

Wireless Personal Communications - Designing an efficient routing protocol for cognitive radio networks is critical due to the dynamic behavior of the primary users. Based on empirical studies, the...