Effect of cerium on the growth and crystalline quality of KDP crystals

The effect of the addition of cerium in potassium dihydrogen phosphate, grown from aqueous solution by the temperature lowering method using bi-direction seed rotation technique has been studied. The optimal addition of trivalent cerium ions considerably prevents other bivalent transition metal ions (Co, Ni, Mn) from entering into the crystal lattice and results in reduced defects and dislocations. A simple microcontroller based bi-directional accelerated seed rotation control setup is designed and employed to avoid stagnant regions or re-circulating flows in the solution. High-resolution XRD analysis of the (002) plane reveals that the Ce³⁺ added KDP exhibited better crystalline perfection and contains less dislocation.     

Association Rule Mining Frequent-Pattern-Based Intrusion Detection in Network

In the network security system, intrusion detection plays a significant role. The network security system detects the malicious actions in the network and also conforms the availability, integrity and confidentiality of data information resources. Intrusion identification system can easily detect the false positive alerts. If large number of false positive alerts are created then it makes intrusion detection system as difficult to differentiate the false positive alerts from genuine attacks. Many research works have been done. The issues in the existing algorithms are more memory space and need more time to execute the transactions of records. This paper proposes a novel framework of network security Intrusion Detection System (IDS) using Modified Frequent Pattern (MFP-Tree) via K-means algorithm. The accuracy rate of Modified Frequent Pattern Tree (MFPT)-K means method in finding the various attacks are Normal 94.89%, for DoS based attack 98.34%, for User to Root (U2R) attacks got 96.73%, Remote to Local (R2L) got 95.89% and Probe attack got 92.67% and is optimal when it is compared with other existing algorithms of K-Means and APRIORI.     

Action selection and task sequence learning for hybrid dynamical cognitive agents

As a foundation for action selection and task-sequencing intelligence, the reactive and deliberative subsystems of a hybrid agent can be unified by a single, shared representation of intention. In this paper, we summarize a framework for hybrid dynamical cognitive agents (HDCAs) that incorporates a representation of dynamical intention into both reactive and deliberative structures of a hybrid dynamical system model, and we present methods for learning in these intention-guided agents. The HDCA framework is based on ideas from spreading activation models and belief–desire–intention (BDI) models. Intentions and other cognitive elements are represented as interconnected, continuously varying quantities, employed by both reactive and deliberative processes. HDCA learning methods—such as Hebbian strengthening of links between co-active elements, and belief–intention learning of task-specific relationships—modify interconnections among cognitive elements, extending the benefits of reactive intelligence by enhancing high-level task sequencing without additional reliance on or modification of deliberation. We also present demonstrations of simulated robots that learned geographic and domain-specific task relationships in an office environment.     

Electrochemical oxidation of lignite in basic media

Electrolysis of lignite slurries in 1N NaOH at Pt electrodes produced humic acids, CO₂, H₂, relatively small amounts of O₂ and traces of CH₄ and C₂H₂. The amount of humic acids that could be precipitated from the electrolyte increased with the applied potential, reached a maximum at E = 2.7 V, SCE and then declined with further increase in electrode potential. The rates of reaction increased with increasing temperature and activation energies computed from limiting currents and overall rates of reaction indicate that the reaction pathway is complex and involves more than one reaction. The current efficiencies for H₂ production were in the range 80–90% and > 50% of the lignite could be reacted at E = 2.0 V (SCE) in 48 h with 4 cm² Pt gauze electrodes. Although a graphite anode is itself electrochemically oxidized when used in this process, it increases reaction rates, ≈ 2–3 times higher with graphite than with Pt. Many aromatic organic compounds can be extracted from the residual reacted coal into suitable solvents. A significant amount of oxygenated organic compounds can also be recovered from the electrolyte as a precipitate after neutralization and by solvent extraction of the filtrate. Various products were characterized by elemental analysis, and gas chromatography-mass spectrometry. Data are also presented to show the influence of electrode potential on the rate of gas production and on the composition of the organic products. Various reaction pathways are hypothesized for the processes which lead to the products observed.     

An innovative method to perform maskless plain waterjet milling for pocket generation: a case study in Ti-based superalloys

This paper presents an innovative methodology/jet path on which plain waterjet (PWJ) can generate pockets of good dimensional/geometrical definition (minimised under/over-erosion) while the proposed method leads to the avoidance of grit embedment on the target workpiece and the elimination of extra cost and time related to the use of mask.The novelty of the paper relies on the proposal of jet-path strategy that minimises the variations in jet dwell time by providing “continuous” relative movement during the jet-part interaction (through minimisation of accelerations/decelerations of the machine head) and by removing a controlled amount of material in a series of layers using special techniques. The proposed method is powerful in its approach from which it ensures (quasi)equal exposure time for each zone of material over which the jet passes, so that the jet path is “totally contained” within the form to be generated; hence, no masking is necessary to define the contour/shape.This approach has been employed for generating pockets on two Ti-based superalloys commonly used in aerospace industries, followed by dimensional, geometrical and surface quality analysis. The results proved that this approach can produce milled surfaces of straightness of the pocket bottom (<200 μm), tolerance on depth of cut per layer (<20 μm), tolerance on the radii at the bottom of the pockets (<100 μm), surface roughness (Ra=4–14 μm) and waviness (Wa=10–13 μm) characteristics in conditions of high surface integrity (no cracks, contaminations, etc.).     

3D scanning-based compression technique for digital hologram video

In this paper, we proposed an efficient coding method for digital hologram video using a three-dimensional (3D) scanning method and two-dimensional (2D) video compression technique. It consists of separation of the captured 3D image into R, G, and B color space components, localization by segmenting the fringe pattern in to M×N [pixel²], frequency-transform by 2D discrete cosine transform (2D DCT), 3D-scanning the segments to form a video sequence, classification of coefficients, and hybrid video coding with H.264/AVC, differential pulse code modulation (DPCM), and lossless coding method. The experimental results with this method showed that the proposed method has compression ratios of 8–16 times higher than the previous researches. Thus, we expect it to contribute to reduce the amount of digital hologram data for communication or storage.     

A multi coding technique to reduce transition activity in VLSI circuits

Advances in VLSI technology have enabled the implementation of complex digital circuits in a single chip, reducing system size and power consumption. In deep submicron low power CMOS VLSI design, the main cause of energy dissipation is charging and discharging of internal node capacitances due to transition activity. Transition activity is one of the major factors that also affect the dynamic power dissipation. This paper proposes power reduction analyzed through algorithm and logic circuit levels. In algorithm level the key aspect of reducing power dissipation is by minimizing transition activity and is achieved by introducing a data coding technique. So a novel multi coding technique is introduced to improve the efficiency of transition activity up to 52.3% on the bus lines, which will automatically reduce the dynamic power dissipation. In addition, 1 bit full adders are introduced in the Hamming distance estimator block, which reduces the device count. This coding method is implemented using Verilog HDL. The overall performance is analyzed by using Modelsim and Xilinx Tools. In total 38.2% power saving capability is achieved compared to other existing methods.     

MOVPE growth of GaAsN: surface study by AFM and optical properties

We report on the growth of GaAs_1−xN_x thin films on GaAs substrates (2° off) by metalorganic vapor-phase epitaxy, in the temperature range 500–600°C. A mixture of N₂ and H₂ was used as the carrier gas. Using dimethylhydrazine as nitrogen source, we incorporated up to 3.5% of nitrogen, at 530°C. The growth condition dependence of nitrogen content was studied, and it reveals a distribution coefficient 350 times lower for nitrogen than for arsine at 530°C. Nitrogen incorporation is controlled by surface kinetics. The evolution of surface morphology has been investigated by atomic force microscopy as a function of the nitrogen composition and of growth temperature. For nitrogen content up to 2%, the GaAsN vicinal surface is characterized by a step–terrace structure with bunched steps, and the step edges straighten when increasing the growth temperature. For higher nitrogen content terraces are no longer observed and, above 3%, widely-spaced cross-hatch lines, characteristic of a partial relaxation of strain in the epilayers, appear. Optical properties were studied by low (7 K) and room-temperature photoluminescence and photoreflectance. As usual for this material, a degradation of optical characteristics is observed with increasing N content along with the evolution of surface morphology.     

Thermal stratification in ribbed liquid hydrogen storage tanks

A significant decrease in the degree of thermal stratification is demonstrated by improvising transverse wall ribs on the inner cylindrical surfaces of large liquid hydrogen storage tanks. The ribbed surfaces are modeled as fins and a conjugate transient heat transfer problem is formulated for predicting flow currents and heat transfer. Turbulent Rayleigh numbers between 1.2×10¹²$1.2\times {10}^{12}$ and 6×10¹⁶$6\times {10}^{16}$ are considered. A stratification parameter based on the moment of energy is defined to quantify the degree of stratification and this parameter is seen to be about 30% lower for the ribbed tanks. The degree of stratification is not sensitive to changes in the ratio of the rib height to the spacing between the ribs. The transient free convection is shown to be characterized by the parameter Fo×Ra^0.15$\mathrm{Fo}\times {\mathrm{Ra}}^{0.15}$. The process of stratification takes place more slowly in the ribbed tanks than in smooth-walled tanks. The free convective heat transfer coefficient for tanks having ribbed surface is also seen to be significantly lower. Incorporation of ribs over the inner surface of the insulated tanks is demonstrated to offer a simple means of reducing the stratification and boil-off losses.     

Microstructure and mechanical properties of friction stir welded joints made from ultrafine grained aluminium 1050

In order to obtain ultrafine grained structure, commercially pure aluminium (Al 1050) plates were subjected up to 8 passes of Incremental Equal Channel Angular Pressing (IECAP) following route C. Plates in different stages of IECAP were joined using Friction Stir Welding (FSW). All welded samples were investigated to determine their mechanical properties and structure evolution in the joint zone. The joining process reduced mechanical strength of material in the nugget zone, which was explained by the grain growth resulting from temperature rise during FSW. Nevertheless, the obtained results are promising in comparison to other methods of joining aluminium.