Hydrothermal Coating of Patterned Carbon Nanotube Forest for Structured Lithium‐Ion Battery Electrodes

Controlling the arrangement and interface of nanoparticles is essential to achieve good transfer of charge, heat, or mechanical load. This is particularly challenging in systems requiring hybrid nanoparticle mixtures such as combinations of organic and inorganic materials. This work presents a process to coat vertically aligned carbon nanotube (CNT) forests with metal oxide nanoparticles using microwave‐assisted hydrothermal synthesis. Hydrothermal processes normally damage delicate CNT forests, which is addressed here by a combination of lithographic patterning, transfer printing, and reduction of the synthesis time. This process is applied for the fabrication of structured Li‐ion battery (LIB) electrodes where the aligned CNTs provide a straight electron transport path through the electrode and the hydrothermal coating process is used to coat the CNTs with conversion anode materials for LIBs. These nanoparticles are anchored on the surface of the CNTs and batteries fabricated following this process show a fourfold longer cyclability. Finally, this process is used to create thick electrodes (350 µm) with a gravimetric capacity of over 900 mAh g^?1.     

Predicting Flood Hazard Indices in Torrential or Flashy River Basins and Catchments

Flood hazard maps are one of the main components of any flood risk management strategy. It is predicted that the degree of flood risk is going to significantly increase in the future due to climatic and environmental changes, and hence it is increasingly important that state-of-the-art methods are implemented for assessing human stability in floodwaters. Therefore, this paper focuses on proposing more accurate and detailed guidelines for predicting flood hazard indices in small and steep river basins or catchments, prone to the occurrence of flash flooding. The results obtained in this study indicate that for river basins with an average bed gradient greater than 1% (i.e. torrential or flashy river basins or catchments), then the flood hazard indices should be predicted using criteria which are based on the physical interpretation of the processes that affect the human stability in floodwaters, i.e. mechanics based and experimentally calibrated flood hazard assessment methods.     

THE TRANSFORMATION OF CYANIDED 18CrMnTi and 18CrMnMo STEELS

用金相法测定了18CrMnTi与18CrMnMo钢高温氰化层经860℃奥氏体化后的恒温C-曲线与马氏体开始转变温度M_H,同时也测定了A_1温度。为了探索氮对过冷奥氏体转变特性的影响,还将这两种钢进行了固体渗碳处理,使渗碳试样具有和高温氰化试样实际上相同的含碳量,然后将二者进行了平行试验。 实验结果指出:氰化试样较渗碳试样具有较低的A_1温度、高得多的M_H点、和过冷奥氏体在珠光体与异茵体区间转变时较短的孕育期。 实验中发现,在珠光体及上贝茵体形成之前,氰化试样中均有一种过剩相沿奥氏体晶粒边界析出。这种先析相可能是一种含氮的化合物,其析出为珠光体及上贝茵体的非自发形核提供了现成的有利界面,并使奥氏体合金化程度降低,因而加速了转变。     

Reducing false rate packet recognition using Dual Counting Bloom Filter

Distributed Denial of Service (DDoS) attacks are a serious threat to Internet security. A lot of research effort focuses on having detection and prevention methods on the victim server side or source side. The Bloom filter is a space-efficient data structure used to support pattern matching problems. The filter is utilised in network applications for deep packet inspection of headers and contents and also looks for predefined strings to detect irregularities. In intrusion detection systems, the accuracy of pattern matching algorithms is crucial for dependable detection of matching pairs, and its complexity usually poses a critical performance bottleneck. In this paper, we will propose a novel Dual Counting Bloom Filter (DCBF) data structure to decrease false detection of matching packets applicable for the \(\textit{SACK}^2\) algorithm. A theoretical evaluation will determine the false rate probability of detection and requirements for increased memory. The proposed approach significantly reduces the false rate compared to previously published results. The results indicate that the increased complexity of the DCBF does not affect efficient implementation of hardware for embedded systems that are resource constrained. The experimental evaluation was performed using extensive simulations based on real Internet traces of a wide area network link, and it was subsequently proved that DCBF significantly reduces the false rate.     

Optical spectroscopy study of nc-Si-based p–i–n solar cells

In the present study we analyzed nanocrystalline silicon (nc-Si)-based p–i–n thin film structures (SiC/nc-Si/n-doped amorphous Si) on glass produced by radio-frequency plasma-enhanced chemical vapor deposition. The crystallinity of the nc-Si layer was modified by varying the deposition conditions ([SiH₄]/[H₂] ratio in the plasma and radio-frequency power). Structural properties of the samples (crystalline fraction and crystal size distribution) were inferred by Raman spectroscopy. Different optical spectroscopy methods were combined for the determination of the optical constants in different spectral ranges: spectrophotometry, ellipsometry and photothermal deflection spectroscopy. Characterization results evidence that the optical properties of the nc-Si layers are strongly connected with the layer structural properties. Thus, the correlation between density of defects, Urbach energy, band-gap and line-shape of dielectric function critical points with the crystalline properties of the films is established.     

Evaluating the effectiveness of the security quality requirements engineering (SQUARE) method: a case study using smart grid advanced metering infrastructure

This paper presents an evaluation of the security quality requirements engineering (SQUARE) method. The evaluation of SQUARE was conducted by its application on the advanced metering infrastructure of smart grid as a case study. We evaluated the effectiveness of SQUARE with respect to its ability to elicit a set of artifacts, threats, and vulnerabilities; to perform likelihood, impact analysis, and risk level determination; and to elicit, categorize, and prioritize the security requirements. The main contribution of this work is the evaluation of the effectiveness of SQUARE using qualitative security requirements engineering method evaluation criteria.     

Phase relations and electrical properties in the pseudo-ternary La2O3–TiO2–Mn2O3 system in air

Scanning electron microscopy (SEM), electron-probe microanalysis, energy- and wavelength-dispersive X-ray analysis and X-ray powder diffraction were used to investigate the subsolidus phase relations in the pseudo-ternary La₂O₃–TiO₂–Mn₂O₃ system in air (oxygen partial pressure p_O2=0.21   atm) at 1275 °C. The addition of Mn₂O₃ to the starting La₂O₃:3TiO₂ mixture led to the formation of a La-deficient perovskite La_2/3TiO₃ compound. The oxides form two new compounds with the proposed compositions: (i) La_1.7Ti_13.0Mn_6.3O_38−x, with a davidite-like crystal structure, and (ii) La₄₉Ti₁₈Mn₁₃O₁₂₉. There were also several solid solutions existing over a wide range of concentrations.     

Experimentally observable transitions between dynamical states in complex reaction systems

Identification of trends and their correspondence with dynamical state transitions are briefly discussed on several reaction network models. The influence of different threshold values on the trend analysis and dynamical state analysis results is examined. Both methods are applied here to the results of the numerical simulation. For this purpose the models of three reaction systems are used: simple model of consecutive, first order, equilibrium reactions, partial oxidation of cyclohexane, and model of the oscillatory reaction Bray Liebhafsky.Detailed kinetic analysis confirmed that transient dynamical states may be identified through the symbolic representation of the sequence of trend episodes in experimentally obtainable time series. Stoichiometric Network Analysis of possible dynamical states was used to identify reaction pathways responsible for the sequences of trend episodes. Some technical problems were also addressed, connected with selection of the threshold value and dynamical state notion.     

Fuel Element Simulators for Investigating Accident Regimes on Full-Scale Stands

The characteristics of structurally different fuel element simulators are presented. It is shown that an indirectly heated fuel element simulator with an auxiliary cladding has advantages over existing simulators and makes it possible to achieve heat flux densities comparable to or higher than the normal loads for VVER. __________ Translated from Atomnaya Energiya, Vol. 99, No. 2, pp. 108–114, August 2005.     

Intelligent Computer Integrated Structures

Abstract: One is still bound to known structural forms and implementing mostly known materials and known technology. It is possible to implement in contemporary design new information technology and advances from other technical fields, to save energy and material resources and implement new forms more suitable to some of the material used. It is shown that new advances in material use and technology implementation should be reflected in new forms. Notably, the implementation of robotics and neural network technology could change the established structural forms. Implementing the computers to maintain the structural safety and integrity in ICIS may be sought, where computers are integral parts of the whole structure as are other more common structural parts.