Uncertainty Assessment in Cognitive Load for Multiple Object Tracking Based on EEG

Cognitive load varies the attention level, which has serious consequences in complex dynamic situations. Assessment of uncertainty in cognitive load during multiple object tracking task is necessary, as it is used to improve the cognitive capabilities. The present research work investigates the uncertainty in cognitive load of multiple object tracking task using electroencephalograph (EEG) on 25 football players. A d2 test of neuropsychological measure of attention was employed before starting the experiment. Each player participated in four levels of the task with variation in the cognitive load, which varies in terms of the targets from 2 to 5. Percentage changes in the power spectral density were estimated for the cognitive levels. Results show that the percentage changes were much more in high cognitive load than in low cognitive load. Significant changes (p < 0.05) were observed in level 1 (− 11.07 to 1.91%), level 2 (− 3.13 to − 14.51%), level 3 (− 6.33 to − 19.46%) and level 4 (− 8.10 to − 20.88%). Variation in the EEG data in terms of the combined uncertainty corresponds very well with low to high cognitive loads. The fourth level of the task with high cognitive load has more uncertainty than the low cognitive load levels. The results are useful for assessing the cognitive state of the player, which is valuable for the design of the effective training model.     

Numerical implementation of drop and tilt method of five-axis tool positioning for tensor product surfaces

The Drop and Tilt tool position method for five-axis machining positions a toroidal tool to have two points of contact with a tensor product Bézier surface. The method results in high order simultaneous non-linear transcendental equations that are slow to solve. In this paper, an efficient numerical implementation of the Drop and Tilt Method of multi-point tool positioning on tensor product surfaces is presented. The method was implemented in C++, and is a direct method that does not convert the tensor product surface into an intermediate representation such as triangles or point clouds. The method is successfully demonstrated on a number of tensor product Bézier surfaces.     

Significantly high electromagnetic shielding effectiveness in polypyrrole synthesized by eco-friendly and cost-effective technique

A facile and eco-friendly synthesis of polypyrrole from monomer pyrrole using nominal amount of ferric chloride hexahydrate (FeCl₃.6H₂O) oxidant in aqueous solution by chemically oxidative polymerization method has been reported. The use of aqueous solvent and ferric chloride hexahydrate salt in polypyrrole synthesis have an eco-friendly route favorable for the production of polypyrrole in large quantities. The synthesized polypyrrole samples exhibit good electrical conductivity (2 S/cm) and yield of 80% for reaction time of 8 hr at 5°C. Quality and properties of polypyrrole samples have been thoroughly investigated with varying reaction time and temperature while other synthesis parameters like molar ratio of oxidant to monomer, oxidant concentration, and solvent were kept constant. X-ray diffraction analysis of polypyrrole with a shorter reaction time shows the presence of iron oxide (Fe₂O₃) peaks. The complete reaction may not occur at shorter reaction times due to which residual ferric ions converted into Fe₂O₃. X-ray photoelectron spectroscopy measurement of polypyrrole also confirms the formation of Fe₂O₃. Appropriate selection of reaction time and temperature produced pure phase polypyrrole with high yield and good conductivity. Synthesized polypyrrole by our eco-friendly and cost-effective technique exhibits prominent electromagnetic shielding effectiveness value of 30 dB in the X-band (8–12 GHz).     

A low-cost Mr compatible ergometer to assess post-exercise phosphocreatine recovery kinetics

Objective

To develop a low-cost pedal ergometer compatible with ultrahigh (7 T) field MR systems to reliably quantify metabolic parameters in human lower leg muscle using phosphorus magnetic resonance spectroscopy.

Materials and methods

We constructed an MR compatible ergometer using commercially available materials and elastic bands that provide resistance to movement. We recruited ten healthy subjects (eight men and two women, mean age ± standard deviation: 32.8 ± 6.0 years, BMI: 24.1 ± 3.9 kg/m²). All subjects were scanned on a 7 T whole-body magnet. Each subject was scanned on two visits and performed a 90 s plantar flexion exercise at 40% maximum voluntary contraction during each scan. During the first visit, each subject performed the exercise twice in order for us to estimate the intra-exam repeatability, and once during the second visit in order to estimate the inter-exam repeatability of the time constant of phosphocreatine recovery kinetics. We assessed the intra and inter-exam reliability in terms of the within-subject coefficient of variation (CV).

Results

We acquired reliable measurements of PCr recovery kinetics with an intra- and inter-exam CV of 7.9% and 5.7%, respectively.

Conclusion

We constructed a low-cost pedal ergometer compatible with ultrahigh (7 T) field MR systems, which allowed us to quantify reliably PCr recovery kinetics in lower leg muscle using ³¹P-MRS.

     

A Novel Approach to Improve Properties of BiFeO3 Nanomultiferroics

In this study we report the synthesis of Bi_1?xIn_xFe_1?yTi_yO₃ (0 ≤ x ≤ 0.1, 0 ≤ y ≤ 0.05) nanoparticles by a simple cost effective solution combustion method. Pure BFO samples shows distorted rhombohedral perovskite structure with space group R3c which is also supported by Fourier transform infrared spectra study. The codoping of In and Ti at A–B sites of BFO (BIFTO) partially distorts the crystal structure, increases the lattice strain, reduces the average particle size (14 nm), and increases the Fe³⁺/Fe²⁺ ratio which significantly affect the observed results. The saturation magnetization increases significantly upon codoping (4.60 emu/gm) by about 12 times than that of pure BFO (0.4 emu/gm). The improved ferromagnetic properties upon codoping is further manifestated in large value of linear magnetoelectric coupling coefficient (4.8 mV/cmOe) which further provides an indirect evidence for the collapse of space modulated spin structure. The activation energy increases with codoping (0.68 eV), although less than 1 eV which indicates that the conduction is still dominated by charged defects.     

Structural development and magnetic phenomenon in Zn–Cr–Fe multi oxide nano-crystals

The Cr³⁺ ions doped multi-oxide ZnFe_2−xCr_xO₄ ferrite nanoparticles have been synthesized by chemical co-precipitation method. Site occupancies of Zn²⁺, Cr³⁺ and Fe³⁺ ions were analyzed using X-ray diffraction data and Buerger's method. The effect of the constituent phase variation on the magnetic hysteresis behavior was examined by saturation magnetization which decreases with the increase in Cr³⁺ content in place of Fe³⁺ ions at octahedral B-site. Typical blocking temperature (T_B) around 90 K was observed by zero field cooling and field cooling magnetization study. Room temperature Mössbauer spectra show two paramagnetic doublets (tetrahedral and octahedral sites). The isomer shifts of both doublets decrease whereas quadrupole splitting and relative area of tetrahedral A-site increases with increasing Cr³⁺ substitution. The dielectric constant (measured on compositions x=0, 0.4, 0.8 and 1.0) increases when the temperature increases as in the semiconductor. This behavior is attributed to the hopping of electrons between Fe²⁺ and Fe³⁺ ions with a thermal activation.     

Significance of interface barrier at electrode of hematite hydroelectric cell for generating ecopower by water splitting

Recent increase in energy demand and associated environmental degradation concern has triggered more research towards alternative green energy sources. Eco‐friendly energy in facile way has been generated from abundantly available iron oxides using only few microliters of water without any external energy source. Hydroelectric cell (HEC) compatible to environment benign, low cost oxygen‐deficient mesoporous hematite nanoparticles has been used for splitting water molecules spontaneously to generate green electricity. Hematite nanoparticles have been synthesized by coprecipitation method. Chemidissociated hydroxyl group presence on hematite surface has been confirmed by infrared spectroscopy (IR) and X‐ray photoelectron spectroscopy (XPS). Surface oxygen vacancies in nanostructured hematite have been identified by transmission electron microscopy (TEM), XPS, and photoluminescence (PL) measurement. Hematite‐based HEC delivers 30 mA current with 0.92 V emf using approximately 500 μL water. Maximum off‐load output power 27.6 mW delivered by 4.84 cm² area hematite‐based HEC is 3.52 times higher than reported 7.84 mW power generated by Li‐magnesium ferrite HEC. Electrochemistry of HEC in different irreversible polarization loss regions has been estimated by applying empirical modeling on V‐I polarization curve revealing the reaction and charge transport mechanism of cell. Tafel slope 22.7 mV has been calculated by modeling of activation polarization overvoltage region of 0.11 V. Low activation polarization indicated easy charge/ion diffusion and faster reaction kinetics of Ag/Zn electrode owing to lesser energy barrier at interface. Dissociated H₃O⁺ ions diffuse through surface via proton hopping, while OH^? ions migrate through interconnected defective crystallite boundaries resulting into high output cell current.     

Green hydroelectrical energy source based on water dissociation by nanoporous ferrite

Dissociation of water molecule occurs on octahedrally coordinated unsaturated suface cations and oxygen vacancies created by lithium substitution in magnesium ferrite. Lower synthesis temperature of ferrite has generated nanopores in microstructure. Dissociated hydronium and hydroxyl ions are transported through surface and capillary diffusion in porous ferrite network towards attached Zn and Ag electrodes. Water molecule dissociation ability of nanoporous ferrite has been exploited to develop a green electrical energy cell, which is a combination of material science and electrode chemistry. The innovated cell has been nomenclatured as hydroelectric cell (HEC). When HEC is partially dipped in deionized water, spontaneously hydroxide and hydronium ions are produced by water molecule dissociation. Hydronium ions trapped in nanopores develop enough electric field that further dissociates physisorbed water molecules. Thereby, the process of water molecule dissociation is accelerated in a bigger way to increase ionic current in the cell. Oxidation of Zn electrode by hydroxide ion and reduction of H₃O⁺ at Ag electrode develop voltage and electric current in the cell. The HEC cell of a 17 cm² area is able to generate a short circuit current of 82 mA and 920 mV emf with a maximum output power of 74 mW, which is three order higher than reported output power 1.4 μW/cm² produced by water in cement matrix. Hydroelectric cell performance is repetitive, stable and possesses potential to replace traditional ways of generating renewable energy in terms of cost and safety. Copyright © 2016 John Wiley & Sons, Ltd.     

A comprehensive review of greenhouse shapes and its applications

Greenhouse technology is a practical option for the production and drying of agricultural products in controlled environment. For the successful design of a greenhouse, the selection of a suitable shape and orientation is of great importance. Of various shapes of greenhouses, the even-span roof and the Quonset shape greenhouses are the most commonly used for crop cultivation and drying. The orientation of greenhouses is kept east–west for maximum utilization of solar radiations. Hybrid and modified greenhouse dryers have been proposed for drying of products. The agricultural products dried in greenhouses are found to be better in quality as compared to open sun drying because they are protected from dust, rain, insects, birds and animals. Moreover, various greenhouses shapes along with their applications have been reviewed.