Recognition of hand gestures on the video stream based on a statistical algorithm with pre-treatment

The goal of this work is human hand detection and gesture recognition. This is a tremendously difficult task as hands can be very varied in shape and viewpoint, they can de open or closed, they can have different finger articulations. It is proposed a combined method of hand gesture recognition based on a statistical image processing algorithm. As a pre-processing algorithm it was applied Lucas-Kanade method and background subtraction algorithm. Object recognition was performed with using of Haar classifiers. The possibility of using gestures for remote control of various devices with different hands position from the camera location was shown

Tuning Nitrogen-Doped Carbon Electrodes via Synthesis Temperature Adjustment to Improve Sodium- and Lithium-Ion Storage

Structural imperfections, heteroatom dopants, and the interconnected pore structure of carbon materials have a huge impact on their electrochemical performance in lithium-ion and sodium-ion batteries due to the specific ion transport and the dominant storage mechanism at surface defect sites. In this work, mesopore-enriched nitrogen-doped carbon (NC) materials were produced with template-assisted chemical vapor deposition using calcium tartrate as the template precursor and acetonitrile as the carbon and nitrogen source. The chemical states of nitrogen, the volume of mesopores, and the specific surface areas of the materials were regulated by adjusting the synthesis temperature. The electrochemical testing of NC materials synthesized at 650, 750, and 850 °C revealed the best performance of the NC-650 sample, which was able to deliver 182 mA·h·g−1 in sodium-ion batteries and 1158 mA·h·g−1 in lithium-ion batteries at a current density of 0.05 A·g−1. Our study shows the role of defect sites, including carbon monovacancies and nitrogen-terminated vacancies, in the binding and accumulation of sodium. The results provide a strategy for managing the carbon structure and nitrogen states to achieve a high alkali-metal-ion storage capacity and long cycling stability, thereby facilitating the electrochemical application of NC materials

Treatment of Multi-Walled Carbon Nanotubes with Dichromic Acid: Oxidation and Appearance of Intercalation

This work is dedicated to the study of the treatment of multi-walled carbon nanotubes (MWCNTs) with dichromic acid. The dichromic acid was formed by dissolving different concentrations of CrO3 in water. The effect of the concentration of dichromic acid on the change in texture characteristics, elemental composition, defectiveness, graphitization degree, and surface chemistry of MWCNTs was investigated using various analytical techniques, such as transmission electron microscopy, energy-dispersive X-ray spectroscopy (EDX), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction, and X-ray photoelectron spectroscopy (XPS). Testing of MWCNTs as electrodes for supercapacitors in 3.5 M H2SO4 solution was carried out using cyclic voltammetry. A decrease in the average diameter of CNTs after treatment was found. The EDX and XPS showed that the oxygen content on the surface of MWCNTs increased after treatment with dichromic acid. The formation of Cr2O3 after treatment with dichromic acid was detected by XPS. High angle annular dark field scanning transmission electron microscopy was used to confirm the intercalation of the chromium-containing compound between graphene layers of MWCNTs after treatment with dichromic acid. It was found that two different types of MWCNTs showed diverse behavior after treatment. The highest specific capacitance of the MWCNTs after treatment was 141 F g−1 (at 2 mV s−1) compared to 0.3 F g−1 for the untreated sample

Effect of Toluene Addition in an Electric Arc on Morphology, Surface Modification, and Oxidation Behavior of Carbon Nanohorns and Their Sedimentation in Water

Carbon nanohorns (CNHs) are attractive for various applications, where a high specific surface area and long dispersion stability in water are important. In the present work, we study these parameters of CNHs prepared by arc evaporation of graphite depending on the conditions of the synthesis and subsequent oxidation in air. It is shown that the addition of toluene in the reactor during the arcing allows obtaining CNHs functionalized with −CHx groups. Heating of CNHs in air at 400 °C leads to substitution of −CHx groups for oxygen-containing groups. Moreover, the CNH endcaps are opened at 500 °C, and as a result, the specific surface area of CNHs increases 4 times. Aqueous suspensions with a concentration of oxidized CNHs of 100 µg/mL are stable for 8 months

Tuning Nitrogen-Doped Carbon Electrodes via Synthesis Temperature Adjustment to Improve Sodium- and Lithium-Ion Storage

Structural imperfections, heteroatom dopants, and the interconnected pore structure of carbon materials have a huge impact on their electrochemical performance in lithium-ion and sodium-ion batteries due to the specific ion transport and the dominant storage mechanism at surface defect sites. In this work, mesopore-enriched nitrogen-doped carbon (NC) materials were produced with template-assisted chemical vapor deposition using calcium tartrate as the template precursor and acetonitrile as the carbon and nitrogen source. The chemical states of nitrogen, the volume of mesopores, and the specific surface areas of the materials were regulated by adjusting the synthesis temperature. The electrochemical testing of NC materials synthesized at 650, 750, and 850 °C revealed the best performance of the NC-650 sample, which was able to deliver 182 mA·h·g−1 in sodium-ion batteries and 1158 mA·h·g−1 in lithium-ion batteries at a current density of 0.05 A·g−1. Our study shows the role of defect sites, including carbon monovacancies and nitrogen-terminated vacancies, in the binding and accumulation of sodium. The results provide a strategy for managing the carbon structure and nitrogen states to achieve a high alkali-metal-ion storage capacity and long cycling stability, thereby facilitating the electrochemical application of NC materials

Single-Walled Carbon Nanotubes with Red Phosphorus in Lithium-Ion Batteries: Effect of Surface and Encapsulated Phosphorus

Single-walled carbon nanotubes (SWCNTs) with their high surface area, electrical conductivity, mechanical strength and elasticity are an ideal component for the development of composite electrode materials for batteries. Red phosphorus has a very high theoretical capacity with respect to lithium, but has poor conductivity and expends considerably as a result of the reaction with lithium ions. In this work, we compare the electrochemical performance of commercial SWCNTs with red phosphorus deposited on the outer surface of nanotubes and/or encapsulated in internal channels of nanotubes in lithium-ion batteries. External phosphorus, condensed from vapors, is easily oxidized upon contact with the environment and only the un-oxidized phosphorus cores participate in electrochemical reactions. The support of the SWCNT network ensures a stable long-term cycling for these phosphorus particles. The tubular space inside the SWCNTs stimulate the formation of chain phosphorus structures. The chains reversibly interact with lithium ions and provide a specific capacity of 1545 mAh·g−1 (calculated on the mass of phosphorus in the sample) at a current density of 0.1 A·g−1. As compared to the sample containing external phosphorus, SWCNTs with encapsulated phosphorus demonstrate higher reaction rates and a slight loss of initial capacity (~7%) on the 1000th cycle at 5 A·g−1

Effect of boron and nitrogen additives on structure and transportproperties of arc-produced carbon

We have studied the effect of introduction of boron, nitrogen or both elements into an electric arc on the morphology and the conductivity of the resultant carbon products. Scanning and transmission electron microscopies showed that the use of a boron-filled graphite electrode and a nitrogen gas during the arc discharge synthesis strongly affects the growth kinetics of carbon nanoparticles. The addition of boron promotes the formation of short, defective carbon nanotubes. In contrast, involvement of nitrogen in the synthesis process produces more perfect carbon nanostructures, including graphitic plates. Evaporation of a boron-filled electrode in a nitrogen atmosphere leads to BN co-doping of the carbon product. The concentration of each dopant is ca. 1 at.% and this value is twice greater than that for the cases of individual dopants. Among the studied materials, the BN-doped one possessed the highest conductivity, and this was attributed to the synergetic effect of co-doping. A substitution of carbon atoms by boron or nitrogen resulted in the p- or n-type doping of the samples, respectively. The evolution of conductivity with temperature and magnetic field showed that transport properties of the arc discharge synthesis products are strongly dependent on the charge carrier concentration, morphology and crystallinity of carbon nanoparticles