Foundation For Risk Assessment Research Articles

Experimental and computational fluid dynamic (CFD) simulation of leak shapes and sizes for gas pipeline

In this paper, a parametric study has been carried out to predict the exit velocity of air through the leakage in the pipe with the help of CFD software ANSYS Fluent. The effect of air pressure in the pipe and the shape of leakage have been studied. Further experiments were also carried out to determine the exit velocity for the defined shape of leakage by varying the air pressure in the pipe. Experimentally, the velocity at a distance of 8 cm from the location of a leak in the horizontal plane was obtained with the help of differential pressure transducers. Using the experimental results, the computational results were validated. The results of the parametric simulation study showed that even for a pressure of 2 bars the velocity profile at the leak location indicates the supersonic state where the Mach number is greater than 1. The study is useful because it may be used as a foundation for risk assessment and safety management in the case of flammable gas leaks through gas pipes.

Public Behavior in Urban Parks during Pandemics as a Foundation for Risk Assessment by Park Managers: A Case Study in Saudi Arabia

Accessing parks without transmitting viruses would ensure not depriving people of parks’ health benefits during pandemics. This study attempts to develop a practical tool for park managers to assess the risk of contracting respiratory contagious illnesses, decide on meaningful mitigation measures, and monitor the effect of these measures. The assessment is based on the spatial and temporal behaviors of users at each park open space type (POST), particularly the behaviors that may impact the risk of illness transmission. The researcher created a checklist, including five factors relating to users: physical distancing, density, duration of stay, percentage of users wearing masks, and frequency of surface touch; then, the implementation of the tool was demonstrated by selecting a sample zone from Jeddah waterfront park, Saudi Arabia, while COVID-19 was active. User behavior data were collected at the POSTs of the sample zone, using behavioral mapping and tracking methods. After analyzing the data using ArcGIS Desktop and SPSS Statistics software, the data were used to fill out the composed checklist to assess the risk at POSTs. The findings indicated that the waterfront railing area, playground, and pier were the POSTs with the highest risk. By using the checklist, park managers can contribute to the success of non-pharmaceutical mitigation interventions at a local scale.

Coronary Artery Disease Risk Assessment in Sedentary and Active Patients: Medical Risk, Behavioral Psychology, and the Standard of Care

Objective: A practical approach to determining risk in sedentary and active patients for coronary artery disease. Identify how personal/family history, atherogenic risk factors, and coronary calcium are essential to determining and predicting risk potential. Materials/Methods: Review of the medical, behavioral psychology, and standard of care literature to identify how human psychology, statistical risk of coronary disease, and coronary calcium shape risk prediction. Results: A comprehensive personal/family history, risk factor assessment and comprehensive physical examination are the foundation of risk assessment. Understanding the cognitive process of risk potential is critical to management strategies. Stress testing and coronary calcium scoring are useful adjuncts when initial screening is suggestive of intermediate atherogenic risk. Conclusion: Comprehensive personal/family history, risk factor assessment, comprehensive physical examination, cognitive processing of risk potential, stress testing and calcium scoring all have a role in risk assessment of sedentary and active patients.

Interdependency of construction safety hazards from a network perspective: a mechanical installation case

The assumption that safety hazards in construction projects are independent leads to a weak foundation for risk assessments, and related management strategies may be biased. Therefore, understanding interdependencies of hazards is critical to risk assessment in construction safety. This study proposed a qualitative–quantitative hybrid approach to delineating hazard associations. Based on the hazard network model for an elevator installation, we identified the characteristics of the hazard network and determined critical hazard types based on the hazard associations. The main conclusions are: (a) the hazard network topology is characterized by an extremely sparse hazard association distribution, few centers and highly cohesive interrelationships; (b) management should focus on various hazard mitigation strategies rather than relying on causal relationships; (c) ‘wrong sequence’ due to human error is the most critical ‘gatekeeper’ for the various hazards. Our findings contribute to the body of knowledge by revealing characteristics of hazard interdependencies.

A multivariate copula‐based framework for dealing with hazard scenarios and failure probabilities

AbstractThis paper is of methodological nature, and deals with the foundations of Risk Assessment. Several international guidelines have recently recommended to select appropriate/relevant Hazard Scenarios in order to tame the consequences of (extreme) natural phenomena. In particular, the scenarios should be multivariate, i.e., they should take into account the fact that several variables, generally not independent, may be of interest. In this work, it is shown how a Hazard Scenario can be identified in terms of (i) a specific geometry and (ii) a suitable probability level. Several scenarios, as well as a Structural approach, are presented, and due comparisons are carried out. In addition, it is shown how the Hazard Scenario approach illustrated here is well suited to cope with the notion of Failure Probability, a tool traditionally used for design and risk assessment in engineering practice. All the results outlined throughout the work are based on the Copula Theory, which turns out to be a fundamental theoretical apparatus for doing multivariate risk assessment: formulas for the calculation of the probability of Hazard Scenarios in the general multidimensional case ( ) are derived, and worthy analytical relationships among the probabilities of occurrence of Hazard Scenarios are presented. In addition, the Extreme Value and Archimedean special cases are dealt with, relationships between dependence ordering and scenario levels are studied, and a counter‐example concerning Tail Dependence is shown. Suitable indications for the practical application of the techniques outlined in the work are given, and two case studies illustrate the procedures discussed in the paper.

Drought severity–duration–frequency curves: a foundation for risk assessment and planning tool for ecosystem establishment in post-mining landscapes

Abstract. Eastern Australia has considerable mineral and energy resources, with areas of high biodiversity value co-occurring over a broad range of agro-climatic environments. Lack of water is the primary abiotic stressor for (agro)ecosystems in many parts of eastern Australia. In the context of mined land rehabilitation quantifying the severity–duration–frequency (SDF) of droughts is crucial for successful ecosystem rehabilitation to overcome challenges of early vegetation establishment and long-term ecosystem resilience. The objective of this study was to quantify the SDF of short-term and long-term drought events of 11 selected locations across a broad range of agro-climatic environments in eastern Australia by using three drought indices at different timescales: the Standardized Precipitation Index (SPI), the Reconnaissance Drought Index (RDI), and the Standardized Precipitation-Evapotranspiration Index (SPEI). Based on the indices we derived bivariate distribution functions of drought severity and duration, and estimated the recurrence intervals of drought events at different timescales. The correlation between the simple SPI and the more complex SPEI or RDI was stronger for the tropical and temperate locations than for the arid locations, indicating that SPEI or RDI can be replaced by SPI if evaporation plays a minor role for plant available water (tropics). Both short-term and long-term droughts were most severe and prolonged, and recurred most frequently in arid regions, but were relatively rare in tropical and temperate regions. Our approach is similar to intensity–duration–frequency (IDF) analyses of rainfall, which are crucial for the design of hydraulic infrastructure. In this regard, we propose to apply SDF analyses of droughts to design ecosystem components in post-mining landscapes. Together with design rainfalls, design droughts should be used to assess rehabilitation strategies and ecological management using drought recurrence intervals, thereby minimising the risk of failure of initial ecosystem establishment due to ignorance of fundamental abiotic and site-specific environmental barriers, such as flood and drought events.

Foundational Issues in Risk Assessment and Risk Management

This is a perspective article on foundational issues in risk assessment and management. The aim is to discuss the needs, obstacles, and challenges for the establishment of a renewed, strong scientific foundation for risk assessment and risk management suited for the current and future technological challenges. The focus is on (i) reviewing and discussing the present situation and (ii) identifying how to best proceed in the future, to develop the risk discipline in the directions needed. The article provides some reflections on the interpretation and understanding of the concept of "foundations of risk assessment and risk management" and the challenges therein. One main recommendation is that different arenas and moments for discussion are needed to specifically address foundational issues in a way that embraces the many disciplinary communities involved (from social scientists to engineers, from behavioral scientists to statisticians, from health physicists to lawyers, etc.). One such opportunity is sought in the constitution of a novel specialty group of the Society of Risk Analysis.

Predictors of virtual radial arm maze performance in adolescent Italian children

BackgroundComparisons between animal and human neurotoxicology studies are a foundation of risk assessment, but are hindered by differences in measured behaviors. The radial arm maze (RAM), a rodent visuospatial learning and memory task, has a computerized version for use in children, which may help improve comparisons between animal and human studies. ObjectiveTo describe the characteristics and correlates of the virtual radial arm maze (VRAM) in 255 children age 10–15 years from Italy. MethodsWe administered the VRAM using a laptop computer and measured children's performance using the latency, distance, and working/reference memory errors during eight trials. Using generalized linear mixed models, we described VRAM performance in relation to demographic factors, child activities, and several standard neuropsychologic tests (Italian translations), including the Conners Parent Rating Scales-Short Version (CPRS), California Verbal Learning Test (CVLT), Wechsler Intelligence Scales for Children, finger tapping speed, reaction time, and motor skills. ResultsChildren's VRAM performance tended to improve between trials 1 and 6 and then plateaued between trials 6 and 8. Males finished the task 14s faster (95% confidence interval [CI]: −20, −9) than females. Children who played 2+h of video games per day finished 16s faster (CI: −26, −6) and with 34% (CI: 5, 54%) fewer working memory errors than children who reported not playing video games. Higher IQ and better CVLT scores were associated with better VRAM performance. Higher cognitive/inattention CPRS scores were associated with more working (11%; CI: 1, 22) and reference memory errors (7%; CI: 1, 12). ConclusionsConsistent with animal studies, VRAM performance improved over the course of test trials and males performed better than females. Better VRAM performance was related to higher IQ, fewer inattentive behaviors, and better verbal memory. The VRAM may help to improve the integration and comparison between animal and epidemiological studies of environmental neurotoxicants.

Perioperative Risk Assessment Among Patients With Congestive Heart Failure: A Call For Guidelines

Each year, more than 10 million major noncardiac surgical procedures are performed in the United States. Current perioperative risk assessment focusing on ischemic heart disease and adherence to practice guidelines reduces morbidity and mortality. An estimated 10 million people in the United States suffer from ventricular dysfunction (class B), and half are symptomatic (class C), despite medical therapy. Individuals with heart failure who undergo surgical procedures are at higher risk for perioperative complications than those with ischemic heart disease. Currently, there are no consensus statements on the best approaches to risk-stratify individuals with heart failure who undergo surgical procedures. This manuscript reviews the current literature regarding risk assessment and perioperative management of patients with heart failure undergoing noncardiac surgical procedures. The authors will support the widespread use of two-dimensional echocardiogram with Doppler along with clinical criteria as the foundation of risk assessment. A simple algorithm will be discussed to help unify concepts and set the foundations for further research.

Current needs in environmental risk management

Risk assessment and management have become central to many health and environmental issues in recent years. Despite high expectations for the applications of science to identify and manage risks, many of these issues remain controversial. Some of the foundations of risk assessment and management are explored and needs for improvement are identified. Inputs from models, data, and uncertainty analyses are reviewed and goals for risk assessment, management, and communication are considered. Ultimately a better understanding of the strengths and limitations of these processes, primarily by the specialists and decision makers, is a prerequisite to more effective involvement of affected stakeholders in risk management. Unless some better basic understanding is achieved, public expectations and demands for risk management are likely to remain unachievable.

Quantitative Cancer Risk Estimation for Formaldehyde

Of primary concern are irreversible effects, such as cancer induction, that formaldehyde exposure could have on human health. Dose-response data from human exposure situations would provide the most solid foundation for risk assessment, avoiding problematic extrapolations from the health effects seen in nonhuman species. However, epidemiologic studies of human formaldehyde exposure have provided little definitive information regarding dose-response. Reliance must consequently be placed on laboratory animal evidence. An impressive array of data points to significantly nonlinear relationships between rodent tumor incidence and administered dose, and between target tissue dose and administered dose (the latter for both rodents and Rhesus monkeys) following exposure to formaldehyde by inhalation. Disproportionately less formaldehyde binds covalently to the DNA of nasal respiratory epithelium at low than at high airborne concentrations. Use of this internal measure of delivered dose in analyses of rodent bioassay nasal tumor response yields multistage model estimates of low-dose risk, both point and upper bound, that are lower than equivalent estimates based upon airborne formaldehyde concentration. In addition, risk estimates obtained for Rhesus monkeys appear at least 10-fold lower than corresponding estimates for identically exposed Fischer-344 rats.