An effective security measures for nuclear power plant using big data analysis approach

The Journal of Supercomputing - Among the many hacking attempts carried out against information systems for the past few years, cyber-attacks that could lead to a national-level threat included...     

Nickel supported on low-rank coal for steam reforming of ethyl acetate

Ethyl acetate is a volatile organic compound (VOC) that has emerged as a major environmental pollutant and also one of representative components of bio-oil. In this study, mostly metallic Ni particles (size: <10 nm) were finely dispersed on low-rank coal (LRC) by the ion-exchange process. Catalytic steam reforming of ethyl acetate (EA) was performed over Ni supported on Eco LRC (Ni/Eco) to reduce EA emissions and simultaneously produce H₂. EA reforming over 17.7 wt% Ni/Eco at 400 °C results in H₂ yield of 70%–80%; this is comparable to that achieved with reforming over commercial Ni/Al₂O₃. Advantageously, metallic Ni particles are dominant over Ni oxides on LRC, and therefore, the pre-reduction step routinely required for an alumina-supported catalyst can be skipped. Furthermore, deactivation by coking is slower with Ni/Eco than with Ni/Al₂O₃ during long-term operation, probably because of the smaller particle size and preferential adsorption on the coal support.     

Sensors to Monitor CFRP/Concrete Bond in Beams Using Electrochemical Impedance Spectroscopy

The use of inexpensive electrochemical impedance spectroscopy based sensor technology for nondestructive evaluation (NDE) of bond degradation between external carbon fiber-reinforced polymer (CFRP) reinforcement and concrete is examined. Copper tape on the surface of the CFRP sheet, stainless steel wire embedded in the concrete, and reinforcing bars were used as the sensing elements. Laboratory experiments were designed to test the capability of the sensors to detect the debonding of the CFRP from the concrete and to study the effect of short-term (humidity and temperature fluctuations) and long-term (freeze-thaw and wet-dry exposure and rebar corrosion) environmental conditions on the measurements. The CFRP sheet was debonded from the concrete, and impedance measurements were taken between various pairs of electrodes at various interfacial crack lengths. The dependence of the impedance spectra, and of the parameters obtained from equivalent circuit analysis, on the interfacial crack length was studied. Capacitance parameters in the equivalent circuit correlated strongly with the interfacial crack length and can be used to assess the global state of the bond between CFRP sheets and concrete. Impedance measurements taken between embedded wire sensors can be used to detect the location of debonded regions.     

Comparative studies on steam gasification of ash-free coals and their original raw coals

Catalytic gasification of raw coals at mild condition is not realized yet mainly due to deactivation of catalysts via their irreversible interaction with mineral matters in coal. As a means to achieve repeated use of catalysts, four different ash-free coals (AFCs) containing less than 0.2 wt% ash are produced in this work. Steam gasification of ash-free coals (AFCs) and their parent raw coals of various ranks ranging from lignite (Eco) to coking coal (Posco) is performed in a fixed bed reactor at 700–900 °C. Regardless of the rank of the parent raw coals, all the AFCs behave like a highly carbonized coal such that their gasification rate are similarly slow and they exhibit relatively low H₂/CO ratio. The steam gasification and associated CO to CO₂ conversion of the AFCs are, however, significantly enhanced by K₂CO₃, resulting in the higher H₂/CO and CO₂/CO molar ratio.     

Influence of stoichiometry and alkalinity on barium hexaferrite formation via the supercritical water crystallization method

Fine particles of barium hexaferrite were prepared from aqueous solutions of iron nitrate, barium nitrate and potassium hydroxide by utilizing a continuous flow type supercritical water crystallization method. The influence of stoichiometry (Fe/Ba mole ratio) and alkalinity (R) on the product composition and morphology was studied under fixed temperature, pressure and residence time. Experiments were performed with varying Fe/Ba mole ratios and alkali mole ratio (R). Within mole ratio ranges of 0.5< Fe/Ba< 5, BaO-6Fe₂O₃ single phase was produced; and as the Fe/Ba mole ratio increased, α-Fe₂O₃ was also formed and its quantity increased with increasing mole ratio. At an Fe/Ba ratio of 12, stoichiometric mole ratio of BaO-6Fe₂O₃, the only product formed was α-Fe₂O₃ fine particles. In the case of the influence of alkalinity, single phase α-Fe₂O₃ was detected at R of 0.5 and if R exceeded 2, a single phase BaO-6Fe₂O₃ was detected. According to the results of the experiment and the study of reaction mechanisms, the formation of BaO-6Fe₂O₃ proceeds via a non-stoichiometric reaction and the product composition and morphology can be controlled by adjusting the reaction parameters to obtain optimum conditions for Ba(OH)₂ precipitate formation.     

Measurement of electrical conductivity of La0.2Sr0.8Cr0.2Fe0.8O3-�� using gas-tight electrochemical cells

The oxygen partial pressure (pO₂) dependence of the electrical conductivity of La_0.2Sr_0.8Cr_0.2Fe_0.8O_3-?? (LSCrF) was obtained at T?=?750?C1060°C and pO₂?=?10^?18?0.5 atm. The slope of the plot of log ?? vs. log pO₂ is ??1/5 in the p?Ctype region, pO₂?=?10^?5?10^?1 atm. The p-n transition pO₂ increases with increasing temperature. The activation energy for ionic conduction was estimated to be 0.86 eV from an Arrhenius plot of the minimum conductivity vs. reciprocal temperature. At temperatures below 942°C, a plateau in the conductivity isotherm suggests the presence of a two-phase region. Most likely, phase separation occurs to form a mixture of a perovskite phase and an oxygen vacancy ordered phase related to brownmillerite.     

Label-free electrochemical impedance spectroscopy using a micro interdigitated electrode inside a PCR chip for real-time monitoring

Conventional real-time PCR using fluorescence detection requires expensive optical detection systems with fluorescence labeling. To simplify this PCR system, we proposed an electrochemical impedance spectroscopy (EIS) using an interdigitated electrode integrated inside the PCR chip. The electrode makes a direct contact with the PCR sample and does not require any labeling or immobilization pretreatment. The input AC voltage for EIS showed the lowest noise at 100 mV. Electrical impedances in a frequency domain were measured during 30 cycles in the PCR of Escherichia coli genomic DNA region (of length 180 bp, 10 ng/μl). From the analysis of EIS data, the magnitude of imaginary value steadily increased with an increase in the PCR cycles and showed the greatest change rate at 186 Hz. For comparing the quantitative performance with previous researches, the figure of merit (FM) was defined as the ratio of normalized sensitivity (NS) to the normalized root mean square error (NRMSE). The performance of the proposed EIS method is similar to that reported in other studies, and the damage of the sample monitored through electrophoresis by EIS measurement was confirmed to be negligible.

     

Edge layer embedding algorithm for mitigating on-package variation in 3D clock tree synthesis

A 3D stacked IC is made of multiple dies possibly with heterogeneous process technologies. Therefore, the die-to-die variation between the stacked dies creates on-package variation in a 3D chip. In this paper, we analyze the effect of on-package variation on the 3D clock trees and address the problem of on-package variation aware layer embedding in 3D clock tree synthesis. The layer embedding problem is divided into two sub-problems: clock node embedding and clock edge embedding. While the clock node embedded problem has been intensively investigated by the previous 3D clock tree synthesis flows because the solution directly determines the TSV allocation, the clock edge embedding problem has not been fully addressed yet. We show in this work that a careful clock edge embedding can greatly reduce the impact of on-package variation on the 3D clock skew, thereby enhancing chip yield, and propose a two-step solution to the problem of on-package variation aware layer embedding of clock edges. Specifically, we formulate the edge embedding problem into a problem of maximizing the sharing of layers among the clock paths to minimize the impact of on-package variation globally and solve it efficiently, followed by applying a fine-grained refinement technique to balance the clock latency locally among the clock paths. From the experiments with Benchmark circuits, we confirm that compared to the results produced by the conventional on-package variation unaware layer embedding of clock edges, the proposed algorithm is able to improve the chip yield by 6.2–25.8% and 5.3–44.4% for 2-layered and 4-layered 3D designs, respectively.     

A comparison of spontaneous combustion susceptibility of coal according to its rank

This study investigated spontaneous combustion susceptibility of coal according to the rank. To estimate the spontaneous combustion susceptibility of coal, both crossing-point temperature (CPT) measurement and gas analysis by using gas chromatography (GC) were performed. For the experiment, Eco coal and Kideco coal, Indonesian lignite, and Shenhua coal that is Chinese bituminous coal were used. The lignite such as Eco coal and Kideco coal contains more functional groups that easily react to oxygen more so than Shenhua coal. For this reason, the lignite is more easily oxidized than bituminous coal at low temperature, which results in high O₂ consumption, increase in CO and CO₂ generation, and low CPT. Although the CPT of Eco coal and Kideco coal is identical to each other as they are the lignite, Kideco coal has a lower initial oxidation temperature (IOT) and maximum oxidation temperature (MOT) than those of Eco coal. This means that although each coal has the same rank and CPT, spontaneous combustion susceptibility of coal may vary because the initial temperature of the coal at which oxidation begins may be different due to the substances that participate in oxidation.     

Management of Schemes and Threat Prevention in ICS Partner Companies Security

An analysis of the recent major security incidents related to industrial control systems, revealed that most had been caused by company employees. Therefore, enterprise security management systems have been developed to focus on companies’ personnel. Nonetheless, several hacking incidents, involving major companies and public/financial institutions, were actually attempted by the cooperative firms or the outsourced manpower undertaking maintenance work. Specifically, institutions that operate industrial control systems (ICSs) associated with critical national infrastructures, such as traffic or energy, have contracted several cooperative firms. Nonetheless, ICT's importance is gradually increasing, due to outsourcing, and is the most vulnerable factor in security. This paper proposes a virtualized security management scheme for the resident cooperative firms in the industrial control infrastructure. Since such companies often cannot afford adequate investment in security, the scheme is to let an ICS company provide the virtualized system. One of its merits is the convenience of controlling a VDI server at the center. The cooperative firms were classified, based on their respective security levels, and statistics were collected throughout a four-year period for the results. This paper analyzes the policies and virtualization systems that have been applied to the security of the partner companies, which engaged in ICS security. A suitable model for ICS security was then proposed by analyzing their effects on the system efficiencies, based on the comparisons of the security inspection results obtained before and after virtualization. The proposed system is expected to contribute to industrial safety.