Morphological segmenting and neighborhood pixel-based locality preserving projection on brain fMRI dataset for semantic feature extraction: an affective computing study

Two specific chemical receptive fields of brain, namely the amygdala and the orbital-frontal cortex, are related to valence and arousal in medical experiments. Functional magnetic resonance imaging (fMRI), which is a noninvasive, repeatable, and atomical tool for medical imaging in clinic system, was widely used in affective computing; however, it faces its dataset processing difficulty for dimensional reduction as well as for decreasing the computational complexity. In addition, features extraction from those de-dimensionality datasets is a challenging issue. The current work solved the de-dimensionality issue by using some preprocessing algorithms including clustering, morphological segmenting, and locality preserving projection. In order to keep useful information in fMRI dataset for reduction process, improved neighborhood pixel-based locality preserving projection (NP-LPP) algorithm was addressed and continuously for feature extraction operating using Otsu weighted sum of histogram. Furthermore, a modified covariance power spectral density (MC-PSD) separately in an fMRI Valence–Arousal experiments was measured. The results were analyzed and compared with affective norms English words system. The experiments established that the proposed methods of NP-LPP effectively simplified high complexity of fMRI, and Otsu weighted sum of histogram exhibited superior performance for features extraction compared to the MC-PSD through the calculation root mean standard error. The current proposed method provided a potential application and promising research direction on human semantic retrieval through medical imaging dataset.

     

Is Someone in this Office Available to Help Me?

Robots are increasingly autonomous in our environments, but they still must overcome limited sensing, reasoning, and actuating capabilities while completing services for humans. While some work has focused on robots that proactively request help from humans to reduce their limitations, the work often assumes that humans are supervising the robot and always available to help. In this work, we instead investigate the feasibility of asking for help from humans in the environment who benefit from its services. Unlike other human helpers that constantly monitor a robot’s progress, humans in the environment are not supervisors and a robot must proactively navigate to them to receive help. We contribute a study that shows that several of our environment occupants are willing to help our robot, but, as expected, they have constraints that limit their availability due to their own work schedules. Interestingly, the study further shows that an available human is not always in close proximity to the robot. We present an extended model that includes the availability of humans in the environment, and demonstrate how a navigation planner can incorporate this information to plan paths that increase the likelihood that a robot can find an available helper when it needs one. Finally, we discuss further opportunities for the robot to adapt and learn from the occupants over time.     

Meticulous analysis and consequences of microstructure changes on melt rheology and dynamic viscoelasticity of thermoplastic vulcanizates upon reprocessing

Thermoplastic vulcanizates (TPVs), which are a special class of elastomer alloy, prepared by dynamic vulcanization possess unique morphology of finely dispersed micron‐size cross‐linked elastomeric particles in a continuous thermoplastic matrix. The present study investigates the microstructure formation of elastomeric phase and its associated morphological changes during reprocessing of TPVs based on poly[styrene‐b‐(ethylene‐co‐butylene)‐b‐styrene] triblock co‐polymer (S‐EB‐S) and solution polymerized styrene butadiene elastomer (S‐SBR) by scanning electron microscopy and atomic force microscopy. Semi‐efficient and efficient sulfur‐based curing systems have been adopted to cure the elastomeric phase and a comparative study has been made to demonstrate and explain the effect of reprocessing on the melt rheology and dynamic viscoelasticity of the TPVs. The present work also provides a better insight and guidance to control the microstructure of the cross‐linked elastomeric phase to prepare selectively co‐continuous or dispersed phase morphology. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41182.     

Biocompatible composites of fibrous nanohydroxyapatite embedded in a polydimethylsiloxane

Silicone elastomers have the potential to be a valuable biomaterial due to their mechanical and chemical properties, easy processing, and high gas permeability. Some inherent properties of the pure silicone implant such as high hydrophobicity and low load bearing capacity can be problematic for biomedical applications. The issues were addressed by fabricating hydroxyapatite nanofiber/polydimethylsiloxane nanocomposites. The morphology of nanocomposite structures was visualized by high resolution transmission electron microscopy and field emission scanning electron microscopy. Improved mechanical strength and compliance of the prepared nanocomposite structures were obtained by frequency sweep and creep measurements. Surface hydrophilicity of polydimethylsiloxane was enhanced by hydroxyapatite nanofiber incorporation into the polymer matrix. The cytotoxicity and biocompatibility of the structures were analyzed using breast epithelial cells (MDA MB 231 cell line). These studies showed that the nanocomposite scaffold did not leach any cytotoxic material and showed better cell adhesion and cell proliferation compared to the unfilled elastomer.     

Perforation resistance of five different high-strength steel plates subjected to small-arms projectiles

Thin plates of high-strength steel are frequently being used both in civil and military ballistic protection systems. The choice of alloy is then a function of application, ballistic performance, weight and price. In this study the perforation resistance of five different high-strength steels has been determined and compared against each other. The considered alloys are Weldox 500E, Weldox 700E, Hardox 400, Domex Protect 500 and Armox 560T. The yield stress for Armox 560T is about three times the yield stress for Weldox 500E, while the opposite yields for the ductility. To certify the perforation resistance of the various targets, two different ballistic protection classes according to the European norm EN1063 have been considered. These are BR6 (7.62 mm Ball ammunition) and BR7 (7.62 mm AP ammunition), where the impact velocity of the bullet is about 830 m/s in both. Perforation tests have been carried out using adjusted ammunition to determine the ballistic limit of the various steels. In the tests, a target thickness of 6 mm and 6 + 6 = 12 mm was used for protection class BR6 and BR7, respectively. A material test programme was conducted for all steels to calibrate a modified Johnson–Cook constitutive relation and the Cockcroft–Latham fracture criterion, while material data for the bullets mainly were taken from the literature. Finally, results from 2D non-linear FE simulations with detailed models of the bullets are presented and the different findings are compared against each other. As will be shown, good agreement between the FE simulations and experimental data for the AP bullets is in general obtained, while it was difficult to get reliable FE results using the Lagrangian formulation of LS-DYNA for the soft core Ball bullet.     

Loading Rate Effect on Nanohardness of Soda-Lime-Silica Glass

To understand how hardness, the key design parameter for applications of brittle solids such as glass concerning contact deformation, is affected by loading rate variation, nanoindentation with a Berkovich tip was used to measure the nanohardness of a 330-μm-thick soda-lime-silica glass as a function of loading rate (1 to 1000 mN·s⁻¹). The results showed for the very first time that, with variations in the loading rate, there was a 6 to 9 pct increase in the nanohardness of glass up to a threshold loading rate (TLR), whereafter it did not appreciably increase with further increase in loading rate. Further, the nanohardness data showed an indentation size effect (ISE) that obeyed the Meyer’s law. These observations were explained in terms of a strong shear stress component developed just beneath the nanoindenter and the related shear-induced deformation processes at local microstructural scale weak links. The significant or insignificant presence of shear-induced serrations in load depth plots and corresponding scanning electron microscopic evidence of a strong or mild presence of shear deformation bands in and around the nanoindentation cavity supported such a rationalization. Finally, a qualitative picture was developed for different deformation processes induced at various loading rates in glass.     

Enhancement of convective cooling using oscillating fins

Tailoring the local flow field around a fin can substantially enhance the forced convection heat transfer from a conventional heat sink. A fin is set into oscillation leading to rupture of the thermal boundary layer developed on either side of the fin. This enhancement in heat transfer is demonstrated through an increase in the time-averaged Nusselt Number (Nu) on the fin surfaces. Nu has been found to be strongly dependent on the flow Reynolds Number (Re), the frequency and amplitude of the fin oscillations. A threshold amplitude and frequency is identified beyond which Nu improvements are observed for fixed Re.     

Spent fuel reprocessing: A vital link in Indian nuclear power program

The success of the three stage Indian nuclear energy program is inter-linked with the establishment of an efficient closed fuel cycle approach with recycling of both fissile and fertile components of the spent fuel to appropriate reactor systems. The Indian reprocessing journey was started way back in 1964 with the commissioning of a plant based on PUREX technology to reprocess aluminum clad natural uranium spent fuel from the research reactor CIRUS. After achieving the basic skills, a power reactor reprocessing facility was built to reprocess spent fuel from power reactors. Adequate design and operating experience was gained from these two plants for mastering the reprocessing technology. The first plant, being the maiden venture, based on indigenous technology had to undergo many modifications during its operation and finally needed refurbishment for continued operation. Decommissioning and decontamination of this plant was carried out meticulously to allow unrestricted access to the cells for fresh installation. A third plant was built for power reactor spent fuel reprocessing to serve as a design standard for future plants with the involvement of industry. Over the years, spent fuel reprocessing based on PUREX technology has reached a matured status and can be safely deployed to meet the additional reprocessing requirements to cater to the expanding nuclear energy program. Side by side with the developments in the spent natural uranium fuel reprocessing, irradiated thoria reprocessing is also perused to develop THOREX into a robust process. The additional challenges in this domain are being addressed to evolve appropriate technological solutions. Advancements in the field of science and technology are being absorbed to meet the challenges of higher recovery combined with reduced exposure and environmental discharges.