293 research outputs found
Kinetics of hydrogen sulfide decomposition in a DBD plasma reactor operated at high temperature
The present study investigates the kinetics of hydrogen sulfide (H
2
S) decomposition into hydrogen and sulfur carried out in a nonthermal
plasma dielectric barrier discharge (NTP-DBD) reactor operated at
∼
430 K for in situ removal of sulfur condensed inside the reactor walls.
The dissociation of H
2
S was primarily initiated by the excitation of carrier gas (Ar) through electron collisions which appeared to be the
rate determining step. The experiments were carried out with initial concentration of H
2
S varied between 5 and 25 vol% at 150 mL/min (at
standard temperature and pressure) flow rate in the input power range of 0.5 to 2 W. The reaction rate model based on continuous stirred tank
reactor (CSTR) model failed to explain the global kinetics of H
2
S decomposition, probably due to the multiple complex reactions involved in
H
2
S decomposition, whereas Michaelis-Menten model was satisfactory. Typical results indicated that the reaction order approached zero with
increasing inlet concentration
Catalytic non-thermal plasma reactor for decomposition of dilute chlorobenzene
Oxidative decomposition of low concentrations of chlorobenzene (CB) in air was carried out in a NTP reactor. Typical results indicated the better performance on addition of metal oxide catalysts in plasma zone. It may be concluded that catalytic plasma approach has promise, especially for the removal of low concentraions of CB, where conventional techniques are not energetically feasible. Among the metal oxides studied, AgOx/MnOx showed the better performance than MnOx and CoOx. During the removal of 50 ppm of CB, AgOx/MnOx under humid conditions showed 100% selectivity to total oxidadtion at 260 J L-1, which may be assigned due to the formation of hydroxyl radical and/or due to in situ ozone decomposition on the catalyst surface that may lead to the formation of a powerful oxidant atomic oxygen. Oxidative decomposition of low concentrations of chlorobenzene in air was carried out in a NTP reactor. Results indicated the improved performance on addition of catalysts in plasma zone. It has been observed that the integration of metal oxides, promoted the total oxidation, whose activity was further enhanced on addition of water vapor. During the abatement of 50 ppm of CB, selectivity to CO2 was 100% at 260 J L-1 with AgOx/MnOx/SMF catalytic electrode
Nonthermal plasma assisted photocatalytic oxidation of dilute benzene
Oxidative decomposition of low concentrations (50-1000 ppm) of diluted benzene in air was carried out in a nonthermal plasma (NTP) dielectric barrier discharge (DBD) reactor with the inner electrode made up of stainless steel fibres (SMF) modified with transition metal oxides in such a way to integrate the catalyst in discharge zone. Typical results indicate the better performance of MnOx and TiO2/MnOx modified systems, which may be attributed to the in situ decomposition of ozone on the surface of MnOx that may lead to the formation of atomic oxygen; whereas ultraviolet light induced photocatalytic oxidation may be taking place with TiO2 modified systems. Water vapour improved the selectivity to total oxidatio
人の集団に関する新たな評価方法の考察
九州大学応用力学研究所研究集会報告 No.20ME-S7 「非線形波動の数理と物理」RIAM Symposium No.20ME-S7 Mathematics and Physics in Nonlinear waves本研究では、金融工学の手法を用いて人の混雑を評価する理論の構築を試みた。我々は、人の混雑を表すダイナミクスは確率項を含むLogistic 方程式に従うと仮定し、この動きを正味現在価値やリアルオプション法によって評価した。また、金融工学では、割引率を用いることによってタイミングによる価値の違いが表現されるが今回のモデルでは、割引率を人の効用を割り引くために導入し、実データに基づく推定・考察もあわせて行った
A novel energy-efficient sybil node detection algorithm for intrusion detection system in wireless sensor networks
A Wireless Sensor Network (WSN) is vulnerable to different types of security attacks where the attackers could easily intrude into the network and could cause inexplicable destruction by disrupting the expected functionalities of the network. Severe drainage of battery may occur due to the attacks and as a result, the lifetime of the network may decrease drastically. In this paper, an energy-efficient integrated Intrusion Detection System (IDS) is proposed to detect network layer Sybil attack. Our scheme spots out accurately and purges out the Sybil node which may falsely behave as a genuine node. The experimental results show that the critical factor in WSN, energy is conserved more efficiently by the proposed scheme than the existing alternative methods. Also, accurate detection of the malicious node is possible spending relatively less energy
Spontaneous Unexplained Preterm Labor with Intact Membrane: Finding Protein Biomarkers through Placenta Proteome
Spontaneous unexplained preterm labor with intact membrane (sPTL-IM) remains as an unresolved challenge in obstetrics due to the complex syndromes involved during preterm birth. Two dimensional-gel electrophoresis (2D-GE) coupled with matrix-assisted laser desorption/ionization-time of flight/time of flight (MALDI TOF/TOF) mass spectrometry has become an alternative in screening for potential novel protein-based biomarkers and revealing the pathophysiology of sPTL-IM. To achieve this objective, protein extracted from fetal and maternal sides of the placenta obtained from sPTL-IM (n = 5) and the respective control (n = 10) groups were separated and compared using 2D-gel electrophoresis. MALDI-TOF/TOF mass spectrometry was utilized to identify the differentially expressed proteins between both groups, and the molecular functions of these proteins were studied. A total of 12 proteins were significantly differentiated in sPTL-IM over the control. Differentially expressed proteins were identified to have involved in structural/cytoskeletal components, immune responses, fetal and placenta development, and anticoagulation cascade. More proteins were found to be differentially expressed in the fetal side compared to the maternal side of the placenta. This postulates that the influence of sPTL-IM from fetus is greater than that of the mother. Ultimately, these results might lead to further investigations in elucidating the potential of these proteins as biomarkers and/or drug targets
Catalytic non-thermal plasma reactor for the decomposition of a mixture of volatile organic compounds
The decomposition of mixture of selected volatile organic compounds (VOCs) has been studied in a catalytic non-thermal plasma dielectric barrier discharge reactor. The VOCs mixture consisting n-hexane, cyclo-hexane and p-xylene was chosen for the present study. The decomposition characteristics of mixture of VOCs by the DBD reactor with inner electrode modified with metal oxides of Mn and Co was studied. The results indicated that the order of the removal efficiency of VOCs followed as p-xylene > cyclo-hexane > n-hexane. Among the catalytic study, MnOx/SMF (manganese oxide on sintered metal fibres electrode) shows better performance, probably due to the formation of active oxygen species by in situ decomposition of ozone on the catalyst surface. Water vapour further enhanced the performance due to the in situ formation of OH radicals. [Figure not available: see fulltext.
Multifractal Analysis on the Return Series of Stock Markets Using MF-DFA Method
Part 3: Finance and Service ScienceInternational audienceAnalyzing the daily returns of NASDAQ Composite Index by using MF-DFA method has led to findings that the return series does not fit the normal distribution and its leptokurtic indicates that a single-scale index is insufficient to describe the stock price fluctuation. Furthermore, it is found that the long-term memory characteristics are a main source of multifractality in time series. Based on the main reason causing multifractality, a contrast of the original return series and the reordered return series is made to demonstrate the stock price index fluctuation, suggesting that the both return series have multifractality. In addition, the empirical results verify the validity of the measures which illustrates that the stock market fails to reach the weak form efficiency
Chikungunya: A Potentially Emerging Epidemic?
Chikungunya virus is a mosquito-borne emerging pathogen that has a major health impact in humans and causes fever disease, headache, rash, nausea, vomiting, myalgia, and arthralgia. Indigenous to tropical Africa, recent large outbreaks have been reported in parts of South East Asia and several of its neighboring islands in 2005–07 and in Europe in 2007. Furthermore, positive cases have been confirmed in the United States in travelers returning from known outbreak areas. Currently, there is no vaccine or antiviral treatment. With the threat of an emerging global pandemic, the peculiar problems associated with the more immediate and seasonal epidemics warrant the development of an effective vaccine. In this review, we summarize the evidence supporting these concepts
Water Network Optimization with Wastewater Regeneration Models
The conventional water network synthesis approach greatly simplifies wastewater treatment units by using fixed recoveries, creating a gap for their applicability to industrial processes. This work describes a unifying approach combining various technologies capable of removing all the major types of contaminants through the use of more realistic models. The following improvements are made over the typical superstructure-based water network models. First, unit-specific shortcut models are developed in place of the fixed contaminant removal model to describe contaminant mass transfer in wastewater treatment units. Shortcut wastewater treatment cost functions are also incorporated into the model. In addition, uncertainty in mass load of contaminants is considered to account for the range of operating conditions. Furthermore, the superstructure is modified to accommodate realistic potential structures. We present a modified Lagrangean-based decomposition algorithm in order to solve the resulting nonconvex mixed-integer nonlinear programming (MINLP) problem efficiently. Several examples are presented to illustrate the effectiveness and limitations of the algorithm for obtaining the global optimal solutions.The authors would like to acknowledge financial support from the National Science Foundation for financial support under grant CBET-1437668, the program “Estancias de movilidad en el extranjero “Jose Castillejo” para jóvenes doctores” (JC2011-0051) of the Spanish Ministerio de Educación, and from the University of Alicante (GRE11-19)
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