1,720,967 research outputs found
Material Degradation and NaTech Risk: A Case Study to Discuss Bidirectional Vulnerability in Industrial Systems
Full text linkMaterial degradation is a critical factor in assessing the vulnerability of industrial infra-structure, particularly in the presence of extreme natural events. This study shows that the relation between material degradation and NaTech risk is both bidirectional and systemic, with important implications for industrial safety. Through the analysis of an emblematic case study, it was demonstrated that latent defects, originating during the construction phase, can remain silent for decades and manifest critically under the action of extreme natural events. The objective is to provide a useful methodological tool for the early diag-nosis of systemic risk conditions and for planning preventive and resilient strategies. The proposed approach overcomes the traditional separation between degradation analysis and environmental risk assessment, promoting a holistic and adaptive view of vulnerabil-ity. Specifically, integrating the concept of structural obsolescence into NaTech risk models allows for a more realistic representation of systemic exposure and supports the planning of more effective prevention strategies. The case study analysis highlights the interaction between latent structural defects and environmental stresses, offering insights for inter-preting vulnerability in complex and multifactorial scenarios. The outcome provides per-spectives for the integration of quantitative indicators into NaTech risk models
Hydrogen safety in process industry: Systematization of past lessons
Full text linkInterest in hydrogen has grown due to its potential as a green fuel, because hydrogen combustion produces
only water. However, hydrogen presents two significant challenges: its wide flammability range (4%-75%) and
low ignition energy (0.017 mJ), which make leaks highly flammable, and its small molecular size, which easily
penetrates materials, altering their microscopic and macroscopic properties and causing leaks that are difficult
to detect, increasing the risk of invisible fires. To manage these risks, many studies simulate hydrogen leakage
scenarios to establish accurate safety distances. A thorough understanding of hydrogen leakage behaviour and
failure mechanisms is crucial for risk assessment. This study addresses a gap in the existing literature on
hydrogen-related events. The aim is to identify the most critical equipment in conditions of hydrogen exposure
and material degradation in the process industry, to provide support to inspection and monitoring activities for
more effective risk management. The analysis identifies the chemical, petrochemical and manufacturing sectors
as the most vulnerable to the effects of hydrogen. Corrosion and hydrogen embrittlement are frequent causes
of events, mainly affecting pipelines and often resulting in explosions or fire
Material Degradation: Findings from Historical Accident Analysis in Process Industries
Full text linkMaterial degradation represents a source of risk in the process industry, being responsible for 30% of loss of containment events. This investigation focuses on the analysis of historical events related to material degradation to gain awareness and enhance preparedness in the process industry. A database containing 3,772 records was built. Data collection was performed using industrial-accident open access databases, classifying the information according to macro-sector, type of equipment, substance involved, scenario, age of the plant, actions taken after the event and type of losses. Corrosion emerged as the main failure mechanism, followed by vibration and fatigue. This phenomenon occurs predominantly in plants with more than 25 years of operation, where prolonged exposure to chemical and environmental agents accelerates the degradation of materials. In contrast, more recent plants are more prone to failures caused by vibration. Corrosion events were frequently associated with environmental contamination episodes, with Event Tree Analysis showing it as the most likely scenario, representing approximately 50% conditional probability in documented corrosion incidents. To complete the analysis, two representative case studies were chosen for the application of the quantitative risk assessment. Conditional relationships among the variables of the database were found using Bayesian networks after the first frequentist analysis. This method allowed the investigation of uncertain data revealing a notable rise in the frequency of LOC and toxic gas dispersion. The analysis of past events highlighted the critical failure factors, which can be considered for the adoption of more effective preventive measures
Enhanced Monte Carlo-Assisted Safety Monitoring in Process Industries: a Tank System Case Study
Full text linkSafety is a critical concept in process industries. However, the complexity as the characteristic of process industries brings different challenges when conducting industrial monitoring for the sake of system safety, which is summarized as lacking a holistic view of target systems. In this study, multiple failure modes are considered in the case of a methanol storage tank by applying Hazard and Operability Analysis (HAZOP), with the identified deviations, causes, and consequences. Furthermore, the effects of some failure modes are quantified through the application of Monte Carlo (MC) simulations. Firstly, a model of the methanol storage tank is established through Phenomenology analysis. By sampling different types of failure data, simulation results can reflect system behavior responding to different failure scenarios. As for the safety evaluation of the target system, since flammability is one of the critical hazardous characteristics of the methanol, the flammability diagram is applied to indicate if the system is in a flammable condition during the simulations. Hence, effects from multiple failure modes towards the system flammability are reflected on the flammability diagram, which is allowed to be compared and analyzed in different ways. The results of this study contribute to targeting key variables that are sensible towards multiple failure modes in the tank system. This study is meaningful to practical monitoring activities. A more appropriate monitoring strategy is feasible by focusing on critical variables and critical failure modes. With the capability of simulating the system behavior, it is possible to conduct predictive maintenance strategies and improve current failure prevention measures like intelligent warning systems
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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