Sara Brambilla

Los Alamos National Laboratory, D3 - Systems Analysis and Surveillance, Post-Doc

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Papers by Sara Brambilla

Fuel Surface-Reaction Model for Thick Fuels in Fires

OSTI OAI (U.S. Department of Energy Office of Scientific and Technical Information), Apr 16, 2024

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Review of particle deposition to and removal from clothing, skin, and hair after a radioactive airborne dispersal event

Journal of Environmental Radioactivity, Nov 30, 2023

Dirty bomb source term characterization and downwind dispersion: Review of experimental evidence

Journal of Environmental Radioactivity, Jul 1, 2023

Runaway Prevention in Cumene Hydroperoxide Storage Tanks

In this work thermal runaway of cumene hydroperoxide (CHP) in a storage tank with constant jacket... more In this work thermal runaway of cumene hydroperoxide (CHP) in a storage tank with constant jacket temperature is considered. The divergence method developed by Strozzi and Zaldivar (1994) based on the concept of parametric sensitivity and a runaway criterion focused on a set of critical parameters identified by Velo et al. (1996) have been applied to our system. The results obtained from the computer programs derived from the two methods have been compared and discussed. For the case of our interest the boundaries between safe and runaway zones in the parameter space computed according to the divergence method have proved to be too conservative when compared with Velo et al. (1996) results.

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Simulation of the Lpg Release, Dispersion, and Explosion in the Viareggio Railway Accident

DOAJ (DOAJ: Directory of Open Access Journals), Apr 1, 2010

The manuscript analyzes the accident that occurred in the railway station of Viareggio (Italy) on... more The manuscript analyzes the accident that occurred in the railway station of Viareggio (Italy) on June 2009. A freight train carrying LPG went off the rails and five out of fourteen wagons derailed and overturned. A hole formed in the first tank car due to the impact with a signaling stake. The pressurized LPG was released as a two-phase jet: the liquid phase formed a boiling pool on the ballast while the dense gas dispersed in the atmosphere. The dense cloud spread and moved towards the neighboring houses. Afterwards, the cloud was ignited and exploded. The overpressure destroyed some residential buildings in the area closest to the explosion epicenter, while glasses were shattered in a larger area. Thirty-one people died and a number of residents were injured due to the fires that engulfed the surrounding houses. Starting from the data related to the tank cars, meteorological data, pictures of the site after the accident, aerial photos, witnesses of both civilians, and rescue teams, the manuscript reconstructs the dynamics of the accident by means of a dedicated software.

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The effect of terrain-influenced winds on fire spread in QUIC-Fire

Environmental Modelling & Software

QUIC-Fire: Initial capabilities of a fast-running simulation tool for prescribed fire applications

Imprensa da Universidade de Coimbra eBooks, 2022

Prescribed fire is increasingly being looked to as a tool that can support land and fire managers... more Prescribed fire is increasingly being looked to as a tool that can support land and fire managers in their efforts towards ecological sustainability and wildfire risk management. As prescribed fire use is considered for treatment of more acres and in more complex settings, practitioners are having to work harder to meet their expanding treatment goals in a safe and environmentally responsible manner. In the context of a prescribed fire, the role of multiple ignitions and complex fire geometries depends heavily on feedbacks between the fire and atmosphere and accentuates the need for explicit representation of these processes in any modeling tools that are to be used to support prescribed fire managers. Computational fluid dynamics models like FIRETEC and WFDS are inherently capable of representing this interaction, but they are too computationally expensive for widespread uses by practitioners for exploration and analysis. We have developed a new simulation tool called QUIC-Fire to capture these fire/atmosphere feedbacks while being orders of magnitude less computationally expensive by coupling the fast-running 3-D rapid wind solver QUIC-URB to a physicsbased cellular automata fire spread model Fire-CA. Here we describe some of the model basics and provide initial demonstration capabilities of a new fast-running modeling tool, QUIC-Fire, that can be applied to prescribed fire planning. QUIC-Fire provides a self-determining fire prediction capability that represents the critical coupled fire/atmosphere feedbacks at scales relevant for prescribed fire. Although, the development of this model is in the nascent stages, initial results show an encouraging capability to capture basic trends in fire behavior, response of fire spread to size of fire, consumption of canopy fuels in prescribed fire scenarios, interaction between multiple firelines and response to heterogeneity in vegetation. Its ability to model response to both ignition patterns and a temporally and spatially variable fire environment without computational expense of CFD solutions is encouraging.

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Particle resuspension: Challenges and perspectives for future models

Physics Reports

Using what has become a celebrated catchphrase, Philip W. Anderson once wrote that "more is diffe... more Using what has become a celebrated catchphrase, Philip W. Anderson once wrote that "more is different" (Science, Vol. 177, Issue 4047, pp. 393-396, 1972). First formulated in the context of condensed matter, this statement carries far beyond the sole limits of solid-state physics. It emphasizes that collective behavior can be more than the mere sum of what happens for elementary constituents or the mere collation of the evolution of each degree of freedom. Said otherwise, complex phenomena can arise out of the interplay between multiple sub-phenomena each of which can be relatively simple. The process of particle resuspension, in which discrete particles adhering on a surface are pulled off and carried away by a fluid flow, is another example involving a web of phenomena pertaining to fluid mechanics, particle dynamics and interface chemistry whose crosseffects create an intricate topic. The purpose of this review is to analyze the physics at play in particle resuspension in order to bring insights into the rich complexity of this common but challenging concern. Following the more-is-different vision, this is performed by starting from a range of practical observations and experimental data. We then work our way through the investigation of the key mechanisms which play a role in the overall process. In turn, these mechanisms reveal an array of fundamental interactions, such as particle-fluid, particle-particle and particle-surface, whose combined effects create the tapestry of current applications. At the core of this analysis are descriptions of these physical phenomena and the different ways through which they are intertwined to build up various models used to provide quantitative assessment of particle resuspension. The physics of particle resuspension implies to hold together processes occurring at extremely different space and time scales and models are key in providing a single vehicle to lead us through such multiscale journeys. This raises questions on what makes up a model and one objective of the present work is to clarify the essence of a modeling approach. In spite of its ubiquitous nature, particle resuspension is still at the early stages of developments. Many extensions need to be worked out and revisiting the art of modeling is not a moot point. The need to consider more complex objects than small and spherical particles and, moreover, to come up with unified descriptions of mono-and multilayer resuspension put the emphasis on solid model foundations if we are to go beyond current limits. This is very much modeling in the making and new ideas are proposed to stimulate interest into this everyday but challenging issue in physics.

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In-Depth Introduction to QUIC-Fire

OSTI OAI (U.S. Department of Energy Office of Scientific and Technical Information), Nov 3, 2022

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Quic-Urb and Quic-Fire Extension to Complex Terrain: Development of a Terrain-Following Coordinate System

SSRN Electronic Journal

Established knowledge and open issues in emergency planning and accident responding

Chemical engineering transactions, 2006

QUIC-DEPDOSE: Software tools to prepare for and respond to nuclear emergencies

Photo 3. QUIC-computed radiological parCcle deposiCon onto the ground and building surfaces from ... more Photo 3. QUIC-computed radiological parCcle deposiCon onto the ground and building surfaces from a dirty-bomb detonaCon in Chicago. An important feature of QUIC is that it models how buildings and streets channel parCcle dispersion both horizontally and verCcally. Other plume models do not adequately account for the important effects of buildings, trees, and local topography on plume transport and dispersion.

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A mathematical framework for the selection and ranking of multiple criteria for risk assessment

The book chapter discusses the mathematical algorithm implemented within the PreEmergencies proje... more The book chapter discusses the mathematical algorithm implemented within the PreEmergencies project to quantify the overall emergency preparedness in case of accidents in road tunnels. The methodology choice, the definition of evaluation criteria hierarchy, and their relative importance are detailed.

Adhesion and aerodynamic forces for the resuspension of non-spherical particles in outdoor environments

Journal of Aerosol Science, 2017

Abstract Particles deposited on an outdoor surface can be resuspended by wind gusts, become airbo... more Abstract Particles deposited on an outdoor surface can be resuspended by wind gusts, become airborne, and be inhaled if small enough. If toxic or infectious, these particles may be dangerous for the populace health. It is therefore important to determine under which weather conditions a deposit of particle could be resuspended to implement the best response actions and plan clean-up. To this scope, one needs to consider the competing forces acting on the particle keeping it attached to the surface (gravity and adhesion) or trying to remove it (aerodynamic forces, i.e., lift and drag). This paper reviews the current understanding of the aforementioned forces for colloidal spherical particles and extends the existing theories to rod-shaped particles, representative for instance of Bacillus spores. In particular, for the adhesion force, the Derjaguin approximation was used and the adhesion force was computed from the radii of curvature of the particle and the surface at the point of closest approach. For the aerodynamic forces, we re-derived the equations for the drag and lift forces accounting for the shape of the particle. Both smooth and rough surfaces will be discussed, the former as idealized cases, the latter as more representative of real outdoor surfaces.

Validation of the Biological Agent Event Reconstruction Tool (BERT) Against the Joint Urban 2003 Field Experiment

The source inversion model used in the Biological agent Event Reconstruction Tool (BERT) computes... more The source inversion model used in the Biological agent Event Reconstruction Tool (BERT) computes the potential release location(s) based on air sampler dosage measurements obtained from filters, wind measurements, and estimates of atmospheric stability and boundary-layer depth. BERT utilizes a fast running diagnostic wind model, a segmented Gaussian plume model, and a source inversion methodology called the collector footprint approach. All are simplifications compared to reality and so evaluation of the source inversion scheme is necessary to understand where the approach works well and where it doesn't. In this evaluation study, we have utilized SF6 concentration measurements obtained during the multi-agency Joint Urban 2003 outdoor field experiment held in Oklahoma City. Point source releases were conducted in the central business district and a large number of measurements were obtained up to 4 km downwind. The concentration measurements from the continuous releases are used to back calculate where the source region is located and to provide bounds on the release amount. A number of indicators have been identified to assess BERT performances. In this paper, we present an overview of the model performance broken out by number of collectors hit, day vs. night releases, and time variable vs. steady wind cases.

Validation of the BERT Point Source Inversion Scheme Using the Joint Urban 2003 Tracer Experiment Dataset - Final Report

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Towards the automatic measurement of human performance in virtual environments for industrial safety

ASME 2011 World Conference on Innovative Virtual Reality, WINVR 2011, 2011

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Increasing the Understanding of the BP Texas City Refinery Accident

Computer Aided Chemical Engineering, 2011

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Virtual and Augmented Reality as Viable Tools to Train Industrial Operators

Computer Aided Chemical Engineering, 2012

ABSTRACT The sensitivity and significance of operator training increased profoundly with the incr... more ABSTRACT The sensitivity and significance of operator training increased profoundly with the increase in automation of industrial plants. The paper proposes and discusses the use of Virtual Reality and Augmented Virtual Reality to train industrial operators. A detailed and immersive 3D model of the plant allows the operators understanding the details of equipment and operating conditions. Both the dynamic behavior and the control strategies of the process can be reproduced with a 3D immersive virtual environment by implementing and coupling a dynamic process simulator and a dynamic real-time accident simulator. The AVR feature enhances the VR by adding further information and analysis that result in better understanding of operators that work either in control room or in the field. The proposed training methodology allows achieving significant improvements in reliability, cost effectiveness, environmental friendliness, and process safety. © 2012 Elsevier B.V.

The Thorney Island Dense Gas Dispersion Trials

16th Conference on Air Pollution …, 2010

16th Conference on Air Pollution Meteorology 2.2. The Thorney Island Dense Gas Dispersion Trials.... more

Fuel Surface-Reaction Model for Thick Fuels in Fires

OSTI OAI (U.S. Department of Energy Office of Scientific and Technical Information), Apr 16, 2024

Download

Review of particle deposition to and removal from clothing, skin, and hair after a radioactive airborne dispersal event

Journal of Environmental Radioactivity, Nov 30, 2023

Dirty bomb source term characterization and downwind dispersion: Review of experimental evidence

Journal of Environmental Radioactivity, Jul 1, 2023

Runaway Prevention in Cumene Hydroperoxide Storage Tanks

Download

Simulation of the Lpg Release, Dispersion, and Explosion in the Viareggio Railway Accident

DOAJ (DOAJ: Directory of Open Access Journals), Apr 1, 2010

Download

The effect of terrain-influenced winds on fire spread in QUIC-Fire

Environmental Modelling & Software

QUIC-Fire: Initial capabilities of a fast-running simulation tool for prescribed fire applications

Imprensa da Universidade de Coimbra eBooks, 2022

Download

Particle resuspension: Challenges and perspectives for future models

Physics Reports

Download

In-Depth Introduction to QUIC-Fire

OSTI OAI (U.S. Department of Energy Office of Scientific and Technical Information), Nov 3, 2022

Download

Quic-Urb and Quic-Fire Extension to Complex Terrain: Development of a Terrain-Following Coordinate System

SSRN Electronic Journal

Established knowledge and open issues in emergency planning and accident responding

Chemical engineering transactions, 2006

QUIC-DEPDOSE: Software tools to prepare for and respond to nuclear emergencies

Download

A mathematical framework for the selection and ranking of multiple criteria for risk assessment

Adhesion and aerodynamic forces for the resuspension of non-spherical particles in outdoor environments

Journal of Aerosol Science, 2017

Validation of the Biological Agent Event Reconstruction Tool (BERT) Against the Joint Urban 2003 Field Experiment

Validation of the BERT Point Source Inversion Scheme Using the Joint Urban 2003 Tracer Experiment Dataset - Final Report

Download

Towards the automatic measurement of human performance in virtual environments for industrial safety

ASME 2011 World Conference on Innovative Virtual Reality, WINVR 2011, 2011

Download

Increasing the Understanding of the BP Texas City Refinery Accident

Computer Aided Chemical Engineering, 2011

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Virtual and Augmented Reality as Viable Tools to Train Industrial Operators

Computer Aided Chemical Engineering, 2012

The Thorney Island Dense Gas Dispersion Trials

16th Conference on Air Pollution …, 2010

16th Conference on Air Pollution Meteorology 2.2. The Thorney Island Dense Gas Dispersion Trials.... more

Challenges in industrial dynamics: coupling process simulation with accident simulation

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An analytical tool for assessing the performance of the emergency response machine

The success of emergency response relies on proper emergency preparedness activities to define ar... more The success of emergency response relies on proper emergency preparedness activities to define areas of responsibility, roles, and effective interventions. In this perspective, software tools can be of paramount importance in supporting the decision making process, since the involved authorities are forced to consider the multifaceted factors characterizing the emergency preparedness and response. Specifically, the manuscript focuses on two complementary risk typologies: mounting risk (i.e. floods) and sudden risk (i.e. flash floods or tunnel accidents). The Authors developed a program, which assesses the vulnerability of an inter-organizational civil protection structure by analyzing a number of parameters that pertain to physical, organizational, and contextual features. The Analytical Hierarchy Process methodology, AHP, was applied to the emergency preparedness problem so to structure the available alternatives into a weighted multi-criteria framework while evaluating the performance indexes, and expressing the performance of the emergency system within a specific context.

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Failure simulation and pool-fire radiative effects on nearby process units

This manuscript shows how the connection and interaction between a process dynamic simulator and ... more This manuscript shows how the connection and interaction between a process dynamic simulator and a dynamic accident simulator allow improving operators training, accident investigation, and safety management, by better modeling the feedbacks existing among process units and accidental events. In this perspective, the manuscript presents a rather simplified case study that allows simulating the process dynamic response to an industrial accident comprising a continuous leakage of flammable liquid, the pool spreading, and its final ignition and fire. Interactions between dynamic models of both process and the pool-fire allow investigating radiative effect s on nearby process unit.

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A short cut methodology for flood-technological risk assessment

This paper discusses some methodological issues characterizing the development of a short-cut met... more This paper discusses some methodological issues characterizing the development of a short-cut methodology for Na-Tech risk assessment, with particular reference to the integration between flood – and technological – related hazards. Actually, flood events can involve industrial areas increasing the level of risk for people, especially in densely populated areas where major hazard factories and flooding areas overlap. In spite of its potential high relevance, risk from industrial accidents triggered by floods has so far received little attention.

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Process dynamic and industrial accident simulators: coupling two different worlds into an integrated platform

A shallow water model for dense gas simulation in urban areas

Large quantities of toxic chemicals are stored at industrial facilities and transported around th... more Large quantities of toxic chemicals are stored at industrial facilities and transported around the country via train and truck. In the event of an accidental release, many of these chemicals are released as heavier-than-air gases that stay low to the ground as they are transported by the wind. Breathing height concentrations can remain high due to reduced vertical mixing and hazard zone coverage area can be larger due to near-source gravitational slumping. A number of fast-response dense gas dispersion models have been developed and are routinely used to deal with heavier-than-air releases over unobstructed terrain. If a release were to occur in a built-up environment, however, the effects of buildings and other obstacles will significantly alter the initial spreading, the transport direction , and the amount of mixing of the dense gas cloud. We have developed a new fast-running dense gas dispersion model that is intended for handling releases in cities and at large industrial facilities. In this paper we describe the scheme employed and how the model has been integrated into the Quick Urban & Industrial Complex (QUIC) dispersion modeling system.

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Fast response model for dense gas dispersion accounting for complex geometries

Simulation of the LPG release, dispersion, and explosion in the Viareggio railway accident

The manuscript analyzes the accident that occurred in the railway station of Viareggio (Italy) on... more The manuscript analyzes the accident that occurred in the railway station of Viareggio (Italy) on June 2009. A freight train carrying LPG went off the rails and five out of fourteen wagons derailed and overturned. A hole formed in the first tank car due to the
impact with a signaling stake. The pressurized LPG was released as a two-phase jet: the liquid phase formed a boiling pool on the ballast while the dense gas dispersed in the atmosphere. The dense cloud spread and moved towards the neighboring houses.
Afterwards, the cloud was ignited and exploded. The overpressure destroyed some residential buildings in the area closest to the explosion epicenter, while glasses were shattered in a larger area. Thirty-one people died and a number of residents were injured due to the fires that engulfed the surrounding houses. Starting from the data related to the tank cars, meteorological data, pictures
of the site after the accident, aerial photos, witnesses of both civilians, and rescue teams, the manuscript reconstructs the dynamics of the accident by means of a dedicated software.

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A quantitative assessment of the Viareggio railway accident

Towards the automatic measurement of human performance measurement in virtual environments for industrial safety

Increasing the understanding of the BP Texas City refinery accident

Virtual and augmented reality as viable tools to train industrial operators

The need for developing an improved methodology to better train operators is crucial since their ... more The need for developing an improved methodology to better train operators is crucial since their performance directly influences the process in terms of productivity, quality, profitability, stability, and controllability. Meanwhile, human machine interfaces have intensified the complexity faced by operators in modern plants, where a human error may result in significant financial and resource losses. This paper proposes the implementation and adoption of Virtual Reality (VR) and Augmented-Virtual Realty (AVR) to train operators in industrial plants. A detailed and immersive 3D model of the plant allows the operators understanding the details of both equipment and operating conditions. The complex dynamic behavior and control strategies of the process can be reproduced with a highly detailed 3D virtual environment by employing and coupling a dynamic process simulator and a dynamic real-time accident simulator. The AVR feature allows enhancing and improving the understanding and skill of field operators by letting them know the process operating conditions that dynamically change within the plant section where they work. The same can be said of process dynamics in case of abnormal and accident conditions. The positive outcome of this operator-training tool consists in increasing the reliability, cost effectiveness, environmental friendliness, and safety of the process.

The Thorney Island dense gas dispersion trials

Validation of the Biological Agent Event Reconstruction Tool (BERT) against the Joint Urban 2003 field experiment

Building-aware sensor siting to optimize chemical, biological, and radiological plume detection

In this presentation, a tool that has been developed to optimally site sensors in order protect a... more In this presentation, a tool that has been developed to optimally site sensors in order protect a specific facility, a region in a city, or a military base from a chemical, biological, or radiological agent attack is described. The tool utilizes the Quick Urban & Industrial Complex (QUIC) dispersion modeling system in order to rapidly compute tens of thousands of plumes to use in siting the sensors. In this talk, we describe the concept of "protecting" a built-up site, how the modeling system works, the input requirements, and output products. Validation of the modeling system against experimental data will also be presented, along with a discussion on the model limitations.

High-fidelity liquid pool source term model

Virthualis 3-d visualization technology demo

Validation of the BERT point source inversion scheme using the Joint Urban 2003 tracer experiment dataset – Final report

The report presents the validation of the BioWatch Event Reconstruction Tool (BERT), a 24/7 reach... more The report presents the validation of the BioWatch Event Reconstruction Tool (BERT), a 24/7 reachback resource used after a BioWatch Actionable Result (BAR) is declared to estimate the location(s) of a biological hazardous release within or in the surroundings of a U.S. city. The high quality plume tracer data set obtained during the Joint Urban 2003 outdoor field experiment held in Oklahoma City was used to evaluate the BERT point source inversion scheme, showing the reliability of the tool.

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A mathematical framework for the selection and ranking of multiple criteria for risk assessment

in “Pre-emergency: preparedness, management, communication and lesson learnt in emergences”, Italian Red Cross, Ananke, Torino, ISBN 978-88-7325-234-4, pp. 125-154, 2008, 2008

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