Applications of Bayesian networks and Petri nets in safety, reliability, and risk assessments: A review

YesSystem safety, reliability and risk analysis are important tasks that are performed throughout the system lifecycle to ensure the dependability of safety-critical systems. Probabilistic risk assessment (PRA) approaches are comprehensive, structured and logical methods widely used for this purpose. PRA approaches include, but not limited to, Fault Tree Analysis (FTA), Failure Mode and Effects Analysis (FMEA), and Event Tree Analysis (ETA). Growing complexity of modern systems and their capability of behaving dynamically make it challenging for classical PRA techniques to analyse such systems accurately. For a comprehensive and accurate analysis of complex systems, different characteristics such as functional dependencies among components, temporal behaviour of systems, multiple failure modes/states for components/systems, and uncertainty in system behaviour and failure data are needed to be considered. Unfortunately, classical approaches are not capable of accounting for these aspects. Bayesian networks (BNs) have gained popularity in risk assessment applications due to their flexible structure and capability of incorporating most of the above mentioned aspects during analysis. Furthermore, BNs have the ability to perform diagnostic analysis. Petri Nets are another formal graphical and mathematical tool capable of modelling and analysing dynamic behaviour of systems. They are also increasingly used for system safety, reliability and risk evaluation. This paper presents a review of the applications of Bayesian networks and Petri nets in system safety, reliability and risk assessments. The review highlights the potential usefulness of the BN and PN based approaches over other classical approaches, and relative strengths and weaknesses in different practical application scenarios.This work was funded by the DEIS H2020 project (Grant Agreement 732242)

Quantitative risk assessment using Monte Carlo and dynamic process simulation

Currently, the concern about the industrial risk is a key issue to implement any technology process or to improve the industry competitiveness. In this sense, the risk concept may be considered as the main tool to anticipate behaviors that can lead to further problems. Considering the process industry, different risk analysis techniques are employed to identify hazardous events, to estimate their frequencies and severities, and to characterize the risk, being such tools the best ones to improve the industrial safety. Knowing that, the present Thesis discusses these risk topics to propose four main contributions: (i) new procedure to identify hazardous events; (ii) new procedures to quantify frequency; (iii) new risk definition and representation; and (iv) a method to integrate the proposed procedures to manage a complete risk assessment management. The idea behind the contributions is to use computational tools in new techniques with improved results about the operational risk, helping its obtainment and understanding. Thus, based on a new risk definition that allow better relation between the developed analysis, process simulations are employed to identify hazardous events and Monte Carlo simulations are employed to estimate frequency and to generate a new risk representation characterized by a severity x time x frequency surface. Despite all contributions has its particularity and importance for the risk analyses development, as final contribution, the presented Thesis apply all developed techniques in a case study, proposing an innovative risk assessment procedure.Atualmente, a preocupação com o risco industrial é um ponto chave para implantação de uma nova tecnologia ou para um melhor posicionamento competitivo. Neste sentido, a ideia de risco pode ser considerada como o principal recurso para antever situações que podem gerar problemas futuros. Considerando a indústria de processos, diferentes técnicas de análise de riscos são utilizadas para identificar eventos perigosos, estimar suas frequências e severidades e caracterizar o risco, sendo essas as principais ferramentas para o aumento da segurança industrial. Sabendo disso, a presente tese aborda tais tópicos e propõe quatro contribuições principais: (i) novo procedimento para identificação de eventos perigosos; (ii) novos procedimentos para quantificação de frequência; (iii) nova definição e representação de risco e (iv) um método para integrar os procedimentos propostos em uma avaliação quantitativa de risco completa. A ideia por trás destas contribuições é utilizar procedimentos computacionais que geram resultados mais acurados sobre o risco de uma operação, ajudando em seu entendimento e na obtenção de seu valor. Assim, baseado em um novo conceito de risco que melhor relaciona as análises desenvolvidas, simulações de processos são utilizadas para identificação de eventos perigosos e simulações de Monte Carlo são utilizadas para estimativa de frequência e gerar uma nova representação de risco caracterizada por uma superfície com eixos frequência x severidade x tempo. Apesar de cada contribuição ter sua particularidade e importância para o desenvolvimento das técnicas de análise de risco, como contribuição final, a presente tese aplica todas as técnicas desenvolvidas em um estudo de caso, apresentando assim uma avaliação de risco inovadora

Towards a review of the EC Recommendation for a definition of the term "nanomaterial"; Part 1: Compilation of information concerning the experience with the definition

In October 2011 the European Commission (EC) published a Recommendation on the definition of nanomaterial (2011/696/EU). The purpose of this definition is to enable determination when a material should be considered a nanomaterial for regulatory purposes in the European Union. In view of the upcoming review of the current EC Definition of the term 'nanomaterial' and noting the need expressed by the EC Environment Directorate General and other Commission services for a set of scientifically sound reports as the basis for this review, the EC Joint Research Centre (JRC) prepares three consecutive reports, of which this is the first. This Report 1 compiles information concerning the experience with the definition regarding scientific-technical issues that should be considered when reviewing the current EC definition of nanomaterial. Based on this report and the feedback received, JRC will write a second, follow-up report. In this Report 2 the JRC will provide a detailed assessment of the scientific-technical issues compiled in Report 1, in relation to the objective of reviewing the current EC nanomaterial definition.JRC.I.4-Nanobioscience

Argonne National Laboratory annual report of laboratory directed research and development program activities for FY 1995.

The purposes of Argonne's Laboratory Directed Research and Development (LDRD) Program are to encourage the development of novel concepts, enhance the Laboratory's R&D capabilities, and further the development of its strategic initiatives

Semiconductor Infrared Devices and Applications

Infrared (IR) technologies—from Herschel’s initial experiment in the 1800s to thermal detector development in the 1900s, followed by defense-focused developments using HgCdTe—have now incorporated a myriad of novel materials for a wide variety of applications in numerous high-impact fields. These include astronomy applications; composition identifications; toxic gas and explosive detection; medical diagnostics; and industrial, commercial, imaging, and security applications. Various types of semiconductor-based (including quantum well, dot, ring, wire, dot in well, hetero and/or homo junction, Type II super lattice, and Schottky) IR (photon) detectors, based on various materials (type IV, III-V, and II-VI), have been developed to satisfy these needs. Currently, room temperature detectors operating over a wide wavelength range from near IR to terahertz are available in various forms, including focal plane array cameras. Recent advances include performance enhancements by using surface Plasmon and ultrafast, high-sensitivity 2D materials for infrared sensing. Specialized detectors with features such as multiband, selectable wavelength, polarization sensitive, high operating temperature, and high performance (including but not limited to very low dark currents) are also being developed. This Special Issue highlights advances in these various types of infrared detectors based on various material systems

Microgravity Science and Applications. Program Tasks and Bibliography for FY 1993

An annual report published by the Microgravity Science and Applications Division (MSAD) of NASA is presented. It represents a compilation of the Division's currently-funded ground, flight and Advanced Technology Development tasks. An overview and progress report for these tasks, including progress reports by principal investigators selected from the academic, industry and government communities, are provided. The document includes a listing of new bibliographic data provided by the principal investigators to reflect the dissemination of research data during FY 1993 via publications and presentations. The document also includes division research metrics and an index of the funded investigators. The document contains three sections and three appendices: Section 1 includes an introduction and metrics data, Section 2 is a compilation of the task reports in an order representative of its ground, flight or ATD status and the science discipline it represents, and Section 3 is the bibliography. The three appendices, in the order of presentation, are: Appendix A - a microgravity science acronym list, Appendix B - a list of guest investigators associated with a biotechnology task, and Appendix C - an index of the currently funded principal investigators

Functional Photocatalytic Surfaces for Selective Adsorption and Detection of Organic Pollutants

The dissertation focuses on using unique surface wettability properties to remove oil contamination from water. Three main ideas are explored. In Publication 1, a two-step photocatalytic reduction process creates hierarchical Au nanostructures on a TiO2 film, resulting in a stable surface with superhydrophobic properties. This surface is useful for self-cleaning and anti-icing technologies, as well as applications in cell growth and fluid microchips. Publication 2 introduces a "3-in-1" concept, combining a photocatalytic thin film, micro/nanostructuring, and a low surface energy coating. The resulting surface exhibits superhydrophobicity and photocatalytic activity, suitable for oil-water separation, self-cleaning, and water harvesting. The p-V3D3 coating's stability under UV irradiation and atomic oxygen exposure is advantageous. Publication 3 presents a 4N-in-1 hybrid substrate (AgTiO2) for enhanced Raman spectroscopy. This hybrid substrate achieves significant enhancement, high detection sensitivity, superior photocatalytic degradation performance, and long-term reusability.In summary, this dissertation explores the development of surfaces with unique wettability properties for oil-water separation, self-cleaning, water harvesting, and ultrasensitive Raman spectroscopy. The fabricated surfaces demonstrate improved hydrophilicity, superhydrophobicity, and photocatalytic activity, leading to enhanced performance in various applications

Water oxidation in acid utilising precious and non-precious metal electrocatalysts

In the Proton Exchange Membrane (PEM) water electrolysis industry, it is important to identify an electrocatalyst which is stable in acidic environment for water oxidation reactions. The water oxidation reactions can be divided into two types: four proton and electron transfer reaction, which is the oxygen evolution reaction (OER); and two proton transfer reaction, which is the hydrogen peroxide evolution reaction (2e-WOR). The understanding of the correlation between catalysts’ structure and performance is of significance in water oxidation catalyst design. In this work, we discuss the iridium-based oxides behaviour during the OER, and explored the possibility of hydrogen peroxide generation during the water oxidation reactions using precious and non-precious metals. For iridium-based oxides, a range of crystalline iridium-based oxide catalysts of different particle sizes ranging from 1 – 5 nm were synthesized, using a modified Adams technique. A double-layer capacitance method was developed and used to determine the in situ electrochemically active surface areas (ECSAs) of the OER catalysts in acidic media. The specific double-layer capacitance for iridium oxide was measured across a range of catalysts and determined. These ECSA measurements allow estimations of the specific activity of catalysts, an approach which has hitherto been missing from OER experiments. OER electrochemical performance was measured using the ultra-low loading, high mass transport floating electrode technique in the potential range from 1.3 – 2.0 V. It was found that the iridium oxides showed an impressively good OER performance at high potential with ultra-low Ir loading. Representing a specific activity of 3.75 mA cm-2 (at 1.8 V), corresponding to a turnover frequency of 25 electrons site-1 s-1, and a mass activity of 9900 mA mg-1. A small specific activity increase is seen as the particle size decreases in the low potential range (<1.65 V), but this effect disappears at higher potentials with all catalysts tending towards roughly the same specific activity. To further reduce the Ir loading, different ratios of cobalt was doped onto iridium oxides to test the OER performance in acidic media within the potential range from 1.3 - 2 V. The cobalt doped iridium oxides demonstrated much better OER activities than commercial IrO2. The geometric current density at 1.9 V of Co0.4IrOx showed 300 mA cm-2, while the in-house synthesised IrO2 was around 147 mA cm-2 and a commercial IrO2 less than 20 mA cm-2. The geometric catalyst loadings are 15 ugIr cm-2. The OER mechanism is then proposed to be potential dependent with two different regions: the low current region with surface mechanism, and the OER region with pH-performance dependency suggesting lattice oxygen evolution reaction mechanism. The generation of hydrogen peroxide is also tested during water oxidation reactions with a range of precious and non-precious metal in both acidic and alkaline media. No H2O2 was detected in either condition during the oxidation reactions, by utilizing a modified RRDE system with oxidation reactions occur at both ring and disk electrodes.Open Acces

New York State Energy Research and Development Authority. Research Projects` Update Project Status as of March 31, 1997

This report provides an update of the New York State Energy Research and Development Authority (NYSERDA) program. The NYSERDA research and development program has five major areas: industry, buildings, energy resources, transportation, and environment. NYSERDA organizes projects within these five major areas based on energy use and supply, and end-use sectors. Therefore, issues such as waste management, energy products and renewable energy technologies are addressed in several areas of the program. The project descriptions presented are organized within the five program areas. Descriptions of projects completed between the period April 1, 1996, and March 31, 1997, including technology-transfer activities, are at the end of each subprogram section