Action recognition based on statistical analysis from clustered flow vectors

A new technique for action clustering-based human action representation on the basis of optical flow analysis and random sample consensus (RANSAC) method is proposed in this paper. The apparent motion of the human subject with respect to the background is detected and localized by using optical flow analysis. The next task is to characterize the action through the frequent movement of the optical flow points or interest points at different regions of the moving subject. The RANSAC algorithm is used to filter out any unwanted interested points all around the scene and keep only those that are related to that particular subject’s motion. From the remaining salient key interest points, the area of the human body within the frame is estimated. The rectangular area surrounding the human body is then segmented both horizontally and vertically. Now, the percentage of change of interest points in each horizontal and vertical segments from frame to frame is estimated. Similar results are obtained for different persons performing the same action and the corresponding values are averaged for respective segments. The matrix constructed by this strategy is used as a feature vector for that particular action. Similar data are calculated for each block created at the intersections of the horizontal and vertical segments. In addition to these, the change in the position of the person along X- and Y-axes is accumulated for an action and included in the feature vectors. Afterward, for the purpose of recognition using the extracted feature vectors, a distance-based similarity measure and a support vector machine-based classifiers have been exploited. Several combination of the feature vectors is examined. From extensive experimentation upon benchmark motion databases, it is found that the proposed method offers not only a very high degree of accuracy but also computational savings.     

Cycle life improvement of alkaline batteries via optimization of pulse current deposition of manganese dioxide under low bath temperatures

Pulse current electrodeposition (PCD) method has been applied to the preparation of novel electrolytic manganese dioxide (EMD) in order to enhance the cycle life of rechargeable alkaline MnO₂–Zn batteries (RAM). The investigation was carried out under atmospheric pressure through a systematic variation of pulse current parameters using additive free sulfuric acid–MnSO₄ electrolyte solutions. On time (t_on) was varied from 0.1 to 98.5 ms, off time (t_off) from 0.25 to 19.5 ms, pulse frequencies (f) from 10 to 1000 Hz and duty cycles (θ) from 0.02 to 0.985. A constant pulse current density (I_p) of 0.8 A dm⁻² and average current densities (I_a) in the range of 0.08–0.8 A dm⁻² were applied in all experiments. Resultant materials were characterized by analyzing their chemical compositions, X-ray diffractions (XRD) and scanning electron microscopy (SEM). Electrochemical characterizations carried out by charge/discharge cycling of samples in laboratory designed RAM batteries and cyclic voltammetric experiments (CV). It has been proved that specific selection of duty cycle, in the order of 0.25, and a pulse frequency of 500 Hz, results in the production of pulse deposited samples (pcMDs) with more uniform distribution of particles and more compact structure than those obtained by direct current techniques (dcMDs). Results of the test batteries demonstrated that, in spite of reduction of bath temperature in the order of 40 °C, the cycle life of batteries made of pcMDs (bath temperature: 60 °C) was rather higher than those made of conventional dcMDs (boiling electrolyte solution). Under the same conditions of EMD synthesis temperature of 80 °C and battery testing, the maximum obtainable cycle life of optimized pcMD was nearly 230 cycles with approximately 30 mAh g⁻¹ MnO₂, compared to that of dcMD, which did not exceed 20 cycles. In accordance to these results, CV has confirmed that the pulse duty cycle is the most influential parameter on the cycle life than the pulse frequency. Because of operating at lower bath temperatures, the presented synthetic mode could improve its competitiveness in economical aspects.     

Thermodynamical computations for removal of alkali halides and lead compounds from electric arc furnace dust

Thermodynamical aspects of a separation process, proposed by the authors for the removal of volatile species from EAF dust, have been studied. Computations have been performed using FACT (Facility for Analysis of Chemical Thermodynamics) software. Different conditions have been considered through calculations of equilibrium state. Effects of different additives, temperature and atmosphere at different total pressure were investigated. It has been shown that removal of alkali halides and lead compounds is possible at temperature as low as 900 ^°C. Oxidizing condition helps removal of lead in the form of lead oxide, while reducing condition increases zinc loss due to reduction and evaporation. Higher temperature results in higher vapor pressure of volatile species, but not necessarily in higher amount of removal for volatiles at equilibrium condition. Reduced pressure does not change the thermodynamical conditions of the separation process.     

Elimination of scan blindness in microstrip scanning array antennas using defected ground structure

In this paper, applying DGS to a linear six-element microstrip scanning array antenna, the blindness angle is removed. The method of moments is utilized in analyzing the proposed structure. The technique uses the band-stop characteristics of microstrip line filters to block the surface waves and reduce the coupling between elements that causes the blindness angle.     

Melting of hydrogels containing ammonium nitrate

The fusion of hydrogels containing ammonium nitrate (AN) has been investigated by differential scanning calorimetry (DSC). The polymers used were guar and xanthan gums as well as synthetic polyacrylamide polymers. Water in hydrogels could be classified into three types labeled as ordinary water (hump of the melting peak), intermediate water (broad component of the peak), and bound nonfreezing water (without any phase transition). The temperature of fusion of intermediate water was about 10° to 35°C lower than that of ordinary water. Intermediate and bound water was found in all the gels studied, whereas ordinary water existed mainly in mixtures with total water content higher than 62%. The presence, type, and concentration of a crosslinker had no effect on the amount of bound water in hydrogels containing AN. In such mixtures the amount of nonfreezing water increased with the polymer concentration as well with the AN proportion relative to water and represented in some cases up to 27% of the gel. Cold-crystallization was observed in all cases (except xanthan) and was probably initiated by AN or the crosslinking agent.     

Flooding and drop size in a pulsed disc and doughnut extraction column

The hydrodynamic behavior of a pulsed disc and doughnut column has been investigated using three different systems in the absence of mass transfer. Sauter-mean drop diameter (d₃₂), flooding velocity and holdup at flooding have been measured at different operating conditions. The following operating variables have been studied: pulsation intensity and flow rate of both liquid phases. As expected, smaller mean drop sizes are obtained with the increase of pulsation intensity. The results also show no significant effect of continuous phase flow rate on mean drop size, which increases with increase of dispersed phase flow rate for the operating conditions investigated. A single correlation for the prediction of d₃₂ in the mixer-settler, transition and emulsion regimes of operation is proposed with a mean deviation of 7.32%. The maximum throughput is influenced mainly by pulsation intensity and interfacial tension. Two precise correlations are proposed for predicting flooding velocities in this column. The first is based on operating variables, column geometry, and system physical properties. The second one considers the same variables, except column geometry. Good agreement between prediction and experiments is found for all operating conditions investigated.     

Taming the Beast: Measurement of the Enthalpies of Combustion and Formation of Triacetone Triperoxide (TATP) and Diacetone Diperoxide (DADP) by Oxygen Bomb Calorimetry

Low‐melting paraffin wax was successfully used as a phlegmatizing agent to perform semi‐micro oxygen bomb calorimetry of spectroscopically pure samples of the sensitive explosive peroxides TATP and DADP. The energies of combustion (Δ_cU) were measured and the standard enthalpies of formation (Δ_fH°) were derived using the CODATA values for the standard enthalpies of formation of the combustion products. Whilst the measured Δ_fH° of DADP (Δ_fH°=−598.5 ± 39.7 kJ mol⁻¹) could not be compared to any existing literature value, the measured Δ_fH° value of TATP (Δ_fH°=+151.4 ± 32.7 kJ mol⁻¹) did not correlate well with the only existing experimental value and confirmed that TATP is an endothermic cyclic peroxide.     

Sub-imaging technique to improve phase only filter search capability

A novel application of a phase only filter model, which is implementable in the optical domain, is proposed. In this application, automated target tracking is accomplished with a novel sub-imaging technique with correlation tracking inside a radius of interest. In this technique the image is subdivided and the correlation is tracked by comparing only the autocorrelation of the filter with itself. A radius of interest is used to reduce the number of computations required to track a moving target. Real-world video images are used to demonstrate the performance of the model.     

Nuclear localisation sequence templated nonviral gene delivery vectors: investigation of intracellular trafficking events of LMD and LD vector systems

The impact of a peptide that contains a nuclear localisation sequence (NLS) on intracellular DNA trafficking was studied. We used the adenoviral core peptide mu and an SV40 NLS peptide to condense plasmid DNA (pDNA) prior to formulation with 3beta-[N-(N', N'-dimethylaminoethane)carbamoyl]cholesterol/dioleoyl-L-alpha-phosphatidyl ethanolamine (DC-Chol/DOPE) liposomes to give LMD and LND vectors, respectively. Fluorescent-labelled lipid and peptides plus dye-labelled pDNA components were used to investigate gene delivery in dividing and S-phase growth-arrested cells. Confocal microscopic analyses reveal little difference in intracellular trafficking events. Strikingly, mu peptide associates with nuclei and nucleoli of cells within less than 15 mins incubation of LMD with cells, which suggests that mu peptide has an NLS function. These NLS properties were confirmed by cloning of a mu-beta-galactosidase fusion protein that localises in the nuclei of cells after cytosolic translation. In dividing cells both LMD and LND deliver pDNA(Cy3) to nuclei within 30-45 min incubation with cells. By contrast, pDNA is detected only in the cytoplasm in growth-arrested cells over the period of time investigated, and not in the nuclei. LD systems prepared from DC-Chol/DOPE cationic liposomes and pDNA(Cy3) behave similarly to LMD systems, which suggests that mu peptide is unable to influence trafficking events in this current LMD formulation, in spite of its strong NLS capacity. We further describe the effect of polyethyleneglycol (PEG) on cellular uptake. "Stealth" systems obtained by post-coating LMD particles with fluorescent-labelled PEG molecules (0.5, 5 and 10 mol % fluorescein-PEG(5000)-N-hydroxysuccinimide) were prepared and shown to be internalised rapidly (mins) by cells, without detectable transgene expression. This result indicates that PEG blocks intracellular trafficking of pDNA.