Generic and adaptive probabilistic safety assessment models: Precursor analysis and multi-purpose utilization

Ayoub Ali,Kröger Wolfgang,Sornette Didier 한국원자력학회 2022 Nuclear Engineering and Technology Vol.54 No.8

Motivated by learning from experience and exploiting existing knowledge in civil nuclear operations, we have developed in-house generic Probabilistic Safety Assessment (PSA) models for pressurized and boiling water reactors. The models are computationally light, handy, transparent, user-friendly, and easily adaptable to account for major plant-specific differences. They cover the common internal initiating events, frontline and support systems reliability and dependencies, human-factors, common-cause failures, and account for new factors typically overlooked in many PSAs. For quantification, the models use generic US reliability data, precursor analysis reports, the ETHZ Curated Nuclear Events Database, and experts’ opinions. Moreover, uncertainties in the most influential basic events are addressed. The generated results show good agreement with assessments available in the literature with detailed PSAs. We envision the models as an unbiased framework to measure nuclear operational risk with the same “ruler”, and hence support inter-plant risk comparisons that are usually not possible due to differences in plant-specific PSA assumptions and scopes. The models can be used for initial risk screening, order-ofmagnitude precursor analysis, and other research/pedagogic applications especially when no plantspecific PSAs are available. Finally, we are using the generic models for large-scale precursor analysis that will generate big picture trends, lessons, and insights.

Synthesis of solution processed f-CNT@Bi₂S₃ hybrid film coated linen fabric as a free-standing textile structured photo catalyst

Memon, Anam Ali,Arbab, Alvira Ayoub,Patil, Supriya A.,Mengal, Naveed,Sun, Kyung Chul,Sahito, Iftikhar Ali,Jeong, Sung Hoon,Kim, Hak Sung Elsevier 2018 Applied catalysis. A, General Vol.566 No.-

<P><B>Abstract</B></P> <P>A unique metallic carbon hybrid film, synthesized with synchronized distribution of bismuth sulfide (Bi<SUB>2</SUB>S<SUB>3</SUB>) and exfoliated multiwall carbon nanotubes (MWCNTs), has been proposed for use as freestanding textile electrodes in photo catalysts. The defect-rich morphology of Bi<SUB>2</SUB>S<SUB>3</SUB> nanowire decorated MWCNT hybrid enhances the photocatalytic activity, electronic properties, cyclic stability, and electron pathways. The proposed f-CNT@Bi<SUB>2</SUB>S<SUB>3</SUB>-hybrid linen fabric electrode demonstrated a defect-rich morphology synchronized with high electrical conductivity. These properties greatly enhanced the photocatalytic activity and electron transfer. The high photocatalytic activity is attributed to the synergistic effect of the high electron affinity of MWCNTs and the structural distortion caused by Bi<SUB>2</SUB>S<SUB>3</SUB> nanowires. Degradation of methylene blue dye was accelerated owing to the elevated activity of Bi<SUB>2</SUB>S<SUB>3</SUB> nanowires, which provides fast absorption of contaminants and reduction of oxidative species. Our proposed system of metallic carbon freestanding textile electrode opens the broad applications of textile-based photochemical devices.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A flexible and highly conductive linen fabric is fabricated. </LI> <LI> The fabric is coated with carbon metallic films by doctor blade technique. </LI> <LI> The electrode is durable and highly photocatalytic active. </LI> <LI> The electrode is stable at various bending positions, against water and electrolyte. </LI> <LI> The surface resistance of the carbon metallic films coated fabric is only 19 Ω sq<SUP>−1</SUP>. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Synthesis of highly photo-catalytic and electro-catalytic active textile structured carbon electrode and its application in DSSCs

Memon, Anam Ali,Arbab, Alvira Ayoub,Sahito, Iftikhar Ali,Sun, Kyung Chul,Mengal, Naveed,Jeong, Sung Hoon Elsevier 2017 SOLAR ENERGY -PHOENIX ARIZONA THEN NEW YORK- Vol.150 No.-

<P><B>Abstract</B></P> <P>Due to the growing need of portable smart devices, textile based solar cells have gained widespread attention in the field of wearable electronics. Here, we have demonstrated facile fabrication of metal free DSSCs by printing cotton, polyester and linen fabric counter electrodes with highly photo catalytic and electro catalytic active mesoporous carbon composite composed of highly conductive acid functionalized multi-walled carbon nanotubes decorated with mesoporous activated charcoal. Different mesoporous carbon structures were formulated by varying the concentration of activated charcoal intercalated in the acid functionalized MWCNT matrix. The mesoporous carbon composite with high level of porosity and oxygen rich surface exhibits low charge transfer resistance and excellent electro-catalytic activity for the reduction of tri-iodide ions. The mesoporous carbon composite exhibited 52% higher photo catalytic activity than the acid modified MWCNT. Besides that, in-depth comparison was carried out in between different kinds of textile fabrics coated with the carbon composite. The slight variation in the microporous structures and surface characteristics of cotton, polyester and linen fabrics led to marginal difference in the electrochemical and photovoltaic performance of DSSCs. High mobility of gel electrolyte within the porous structure of mesoporous carbon and textile fabrics assembly demonstrated low R<SUB>CT</SUB> of 0.82Ω, 0.77Ω and 1.37Ω for cotton, polyester and linen respectively. The obtained photovoltaic conversion efficiency of cotton, polyester and linen based DSSCs using gel electrolyte were 6.06%, 6.26% and 5.80% respectively. The suggested TCO and Pt free DSSC assemblies paved a way to the facile fabrication of textile based DSSC.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Photocatalytic and conductive textile counter electrodes (CEs) were synthesized. </LI> <LI> Cotton, Polyester and Linen fabrics were used as CEs substrate. </LI> <LI> CEs were coated with mesoporous Activated Charcoal intercalated carbon composites. </LI> <LI> Flexible CEs showed a very low charge transfer resistance of 0.77Ω. </LI> <LI> Flexible CEs exhibited a highest conversion efficiency of 6.26%. </LI> </UL> </P>

An evidence for an organic N-doped multiwall carbon nanotube heterostructure and its superior electrocatalytic properties for promising dye-sensitized solar cells

Arbab, Alvira Ayoub,Memon, Anam Ali,Sahito, Iftikhar Ali,Mengal, Naveed,Sun, Kyung Chul,Ali, Mumtaz,Jeong, Sung Hoon The Royal Society of Chemistry 2018 Journal of materials chemistry. A, Materials for e Vol.6 No.18

<P>A novel organic heteroatom doping technique is proposed for the synthesis of N-doped multiwall carbon nanotube (MWCNT) heterostructures. The approach involves the effective doping of MWCNTs with nitrogen <I>via</I> a cationised bovine serum albumin (cBSA) protein complex. The cationization of BSA releases an exceptional number of activated nitrogen species present in localized amino groups, which are further embedded into the MWCNT framework. The amino groups present in BSA act as nitrogen donors and surface stabilizing agents to generate a highly conductive and functionalized carbon heterostructure. The doped nitrogen was present in the form of pyridinic and pyrrolic states, as evidenced by XPS analysis. Organic N-doped MWCNTs with predominant pyridinic N atoms displayed superior charge transfer (<I>R</I>CT = 0.06 Ω) owing to their superior electrocatalytic activity. A DSSC fabricated with organic N-doped MWCNT heterostructures exhibited a high conversion efficiency of 9.55%, which was similar to that of a Pt cathode, with an efficiency of 9.89%. The superior electrochemical performance of organic N-doped MWCNT heterostructures is due to the high charge polarization arising from the difference in electronegativity between nitrogen and carbon as well as the structural strain caused by the cationic BSA protein complex. Our proposed system provides new routes for the synthesis of organic heteroatom-doped nanomaterials for promising energy storage devices.</P>

An organic route for the synthesis of cationic porous graphite nanomaterial used as photocatalyst and electrocatalyst for dye-sensitized solar cell

Arbab, Alvira Ayoub,Mengal, Naveed,Sahito, Iftikhar Ali,Memon, Anam Ali,Jeong, Sung Hoon Elsevier 2018 ELECTROCHIMICA ACTA Vol.266 No.-

<P><B>Abstract</B></P> <P>An organic synthesis route is proposed to fabricate cationized porous graphite (cpG) for photocatalyst and electrocatalyst nanomaterial. High crystalline structure of graphite possesses few defects and porous channels. In the proposed research, cpG is fabricated by sonicating graphite in cationized enzyme media followed by exfoliating in the activated charcoal filler. The cationic lipase solution distributed positive surface charges over a bare graphitic sheet, and sonication with activated charcoal filler divulges porous channels along graphite exfoliated matrix structure. The charcoal doping in graphite was modified with the different charcoal content percentage ranging from 0 to 100%. The cationized porous graphite (cpG) material possess high surface area, pore volume and conductivity leads to high photoresponse and electrocatalytic reaction. As photocatalyst, the proposed graphite provide fast degradation of methylene blue dye observed by UV–Vis spectrophotometer. As cathode for dye-sensitized solar cell (DSSCs), cpG provides high electrocatalytic activity with low charge transfer resistance (R<SUB>CT</SUB> = 0.95Ω) and high photovoltaic performance with 9.59% efficiency. The positive charge distribution over graphite sheet attracts plenty of negative iodide ions present in the electrolyte, provide fast reduction-oxidation reaction. Furthermore, porous charcoal filler doping accepts a large amount of gel electrolyte, and fasten interfacial reaction between electrolyte and CE. This cost-effective cationized porous graphite (cpG) nanomaterial can provide new ways towards sustainable energy resources.</P> <P><B>Highlights</B></P> <P> <UL> <LI> An organic route for the synthesis of cationized porous graphite (cpG) nanomaterial is proposed. </LI> <LI> cpG used as photo catalyst and electro catalyst for DSSCs. </LI> <LI> cpG shows excellent degradation of methylene blue dye at very low time interval. </LI> <LI> cpG demonstrated low R<SUB>CT</SUB> of 0.95Ω with high photovoltaic performance. </LI> <LI> cpG cathode outperform Pt. electrode and exhibit 9.59% PCE of DSSCs. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Extensions of Strongly α-semicommutative Rings

Ayoub, Elshokry,Ali, Eltiyeb,Liu, ZhongKui Department of Mathematics 2018 Kyungpook mathematical journal Vol.58 No.2

This paper is devoted to the study of strongly ${\alpha}-semicommutative$ rings, a generalization of strongly semicommutative and ${\alpha}-rigid$ rings. Although the n-by-n upper triangular matrix ring over any ring with identity is not strongly ${\bar{\alpha}}-semicommutative$ for $n{\geq}2$, we show that a special subring of the upper triangular matrix ring over a reduced ring is strongly ${\bar{\alpha}}-semicommutative$ under some additional conditions. Moreover, it is shown that if R is strongly ${\alpha}-semicommutative$ with ${\alpha}(1)=1$ and S is a domain, then the Dorroh extension D of R by S is strongly ${\bar{\alpha}}-semicommutative$.

A Combined Model of Clustering and Classification Methods for Preserving Privacy in Social Networks against Inference and Neighborhood Attacks

Ali Zaghian,Ayoub Bagheri 보안공학연구지원센터 2016 International Journal of Security and Its Applicat Vol.10 No.1

In the last decade online social networks has gained remarkable attention. Facebook or Google+, are example social network services which allow people to create online profiles and share personal information with their friends. These networks publish details about users while some of the information revealed inside is private. In order to address privacy concerns, many social networks allow users to hide their private or sensitive information in their profiles from the public. In this paper, we focus on the problem of information revelation in online social networks by preserving the privacy of sensitive information in their data using machine learning and data mining algorithms. We show how an adversary can launch an inference or neighborhood attack to exploit an online social network using released data and structure of the network to predict the private information and attributes of users. For this purpose, we propose a new data mining based model that uses neighborhood information and attributes details of a user to infer private attributes of user profiles. The proposed model consists of two main parts: a clustering approach to ensure the k-anonymity and a classification algorithm to preserve the privacy against inference attacks. Finally we explore the effectiveness of some sanitization techniques that can be used to combat such inference attacks, and we show experimentally the success of different neighborhood re-identification strategies. Our experimental results reveal that using combination of data mining algorithm can notably help to preserve private and sensitive information in social network data.

A Constrained Predictive Controller for AUV and Computational Optimization Using Laguerre Functions in Unknown Environments

Ali Jabar Rashidi,Bahram Karimi,Ayoub Khodaparast 제어·로봇·시스템학회 2020 International Journal of Control, Automation, and Vol.18 No.3

In this paper, a predictive controller approach is proposed for depth and steer control of an Autonomous Underwater Vehicle (AUV). The predictive controller is an advanced control technique that performs control in form of online at any sampling time. AUV control has a lot of complexity due to the coupled nonlinear dynamics, parametric uncertainty and external disturbances due to underwater conditions. In addition, the AUV in this paper has constraints on actuators, which make its control more complicated. One of the challenges against implementing of predictive controller is their computational burden and the time consuming control operations at each time step. In this research, the Laguerre orthogonal functions are used for the predictive controller design to optimize and educe computational burden in time interval. The designed controller has several advantages such as being online and optimized, high accuracy, implementation capability, interaction with the constraints and robustness to disturbances. In order to demonstrate the efficiency of the method, the proposed controller is simulated for the AUV and the calculation time of the controllers with and without the Laguerre functions is compared with each other. Using Laguerre functions, the simulation results and their implementation on the board show the favorable efficiency and effectiveness of the proposed controller. Additionally, we have compared the proposed method with the LQR method. The obtained results confirm the superiority of various predictive controller methods.

Nonwoven Polyethylene Terephthalate Paper Loaded with Enzyme Coupled Multiwall Carbon Nanotubes for Superior Photocatalytic Activity for Water Remediation

Alvira Ayoub Arbab,Rabia Almas Arain,Raja Fahad Qureshi,Iftikhar Ali Sahito,선경철,정성훈 한국섬유공학회 2019 Fibers and polymers Vol.20 No.4

A highly photocatalytic, carbon coated nonwoven polyethylene terephthalate paper (CCPETP) is developed byusing the wet-laid method for photodegradation of dye effluents from the textile wastewater treatment. The designednonwoven PET paper is coated with Multiwall walled carbon nanotubes (MWCNT) catalyst coupled with cationised enzymeagent. Three different types of enzymatic coupling agents were used i.e. Lipase, Glucose oxidase, and Laccase, respectively. Enzymes are generally globular proteins, packed with amino complex N-terminals, oxygenated amines and hydroxyl atoms. The sequence of the amino acids specifies the structure which in turn determines the catalytic activity of the enzyme. Thecationization of the enzyme under acidic condition (~pH 3), detach the amino/oxygen complex structure from their corestructure and encapsulate over MWCNT surface. The coupled enzyme dissipates functional oxygenated amines, pyrrolic,pyridinic, graphitic and quaternary type of nitrogen contents. The attachment of functionalized surface groups withoutforming any defect-rich vacancy promotes efficient charge generation and photocatalytic degradation of methylene blue dye(MB) particulates. Besides, the suggested low-cost porous PET nonwoven paper helps to absorb a large number of dyemolecules for efficient dye degradation. The excellent photocatalytic activity of the proposed thin CCPETP photocatalyst ismainly attributed to its specific coupled enzyme, high adsorbing capacity of PET paper, and low recombination of thephotogenerated electrons and holes. The optimal loading content of enzyme coupled MWCNT over nonwoven PET paperdecolorized ~99.0 % methylene blue (MB) dye in 100 min. The excellent dye degradation efficiency of this low-cost materialis attributed its surface characteristics and high absorbing properties. The synergistic effect of cluster active sites and thefunctional amine/oxygen surface groups promoting the generation of ˙OH ions for MB degradation. The fabricatednonwoven paper is expected for large industrial applications and will provide a generic route towards the fabrication of textilestructured photocatalyst.

Effects of three different dietary plant protein sources as fishmeal replacers in juvenile whiteleg shrimp, Litopenaeus vannamei

배진호,ALI HAMIDOGHLI,Marouane Sad Djaballah,Salha Maamri,Ayoub Hamdi,Ismail Souffi,Nathaniel Wesley Farris,배승철 한국수산과학회 2020 Fisheries and Aquatic Sciences Vol.23 No.1

Background: As the cost of fishmeal continues to rise, there will be a need to optimize the diet by minimizing dietary fishmeal inclusion in aquafeed. In this study, a 7-week experiment was conducted to evaluate soybean meal, fermented soybean meal (soytide), and sesame meal as fishmeal replacers in whiteleg shrimp, Litopenaeus vannamei. Methods: A 30%-based fishmeal diet was considered as control (CON), six other diets were prepared by replacing 20% or 40% of fishmeal with soybean meal (SB20 and SB40), fermented soybean meal (ST20 and ST40), or sesame meal (SM20 and SM40) from the CON diet. Twenty shrimp with average initial weight of 0.65 ± 0.05 g (mean ± SD) were randomly distributed into 21 tanks (45 L) and fed four times a day. Water temperature was controlled at 28 ± 1 °C and aeration was provided by air stones. Results: Weight gain, specific growth rate, feed efficiency, and protein efficiency ratio of shrimp fed CON showed no significant differences compared to shrimp fed all the other diets. However, growth performance of shrimp fed ST20 diet was significantly higher than those of shrimp fed the SM20 and SM40 diets (P < 0.05). Superoxide dismutase activity (SOD) of shrimp fed CON, ST20, and ST40 diets was significantly higher than those of shrimp fed the SB40 and SM40 diets. But there were no significant differences among shrimp fed CON, SB20, ST20, ST40, and SM20 diets. Also, lysozyme activity of shrimp fed ST20 diet was significantly higher than those of shrimp fed the SB40 and SM40 diets. Although, lysozyme activity of shrimp fed the CON diet was not significantly different compared to shrimp fed all the other experimental diets. Conclusions: Therefore, SB, ST, and SM could replace 40% of fishmeal based on growth performance and lysozyme. According to the SOD activity, SB and SM could replace 20% of fishmeal and ST could replace 40% of fishmeal in juvenile whiteleg shrimp Litopenaeus vannamei.