scholarly journals Thermodynamics of Pyrocumulus: A Conceptual Study

2018 ◽  
Vol 146 (8) ◽  
pp. 2579-2598 ◽  
Author(s):  
Kevin J. Tory ◽  
William Thurston ◽  
Jeffrey D. Kepert
Keyword(s):  
Full Range ◽  
Fire Behavior ◽  
Atmospheric Conditions ◽  
Neutral Buoyancy ◽  
Lightning Strikes ◽  
Plume Temperature ◽  
Conceptual Study ◽  
Lifting Condensation Level ◽  
In Fire ◽  
Insight Into

Abstract In favorable atmospheric conditions, fires can produce pyrocumulonimbus cloud (pyroCb) in the form of deep convective columns resembling conventional thunderstorms, which may be accompanied by strong inflow, dangerous downbursts, and lightning strikes that can produce dangerous changes in fire behavior. PyroCb formation conditions are not well understood and are difficult to forecast. This paper presents a theoretical study of the thermodynamics of fire plumes to better understand the influence of a range of factors on plume condensation. Plume gases are considered to be undiluted at the fire source and approach 100% dilution at the plume top (neutral buoyancy). Plume condensation height changes are considered for this full range of dilution and for a given set of factors that include environmental temperature and humidity, fire temperature, and fire-moisture-to-heat ratios. The condensation heights are calculated and plotted as saturation point (SP) curves on thermodynamic diagrams. The position and slope of the SP curves provide insight into how plume condensation is affected by the environment thermodynamics and ratios of fire heat to moisture production. Plume temperature traces from large-eddy model simulations added to the diagrams provide additional insight into plume condensation heights and plume buoyancy at condensation. SP curves added to a mixed layer lifting condensation level on standard thermodynamic diagrams can be used to identify the minimum plume condensation height and buoyancy required for deep, moist, free convection to develop, which will aid pyroCb prediction.

Flashover and instabilities in fire behavior

1980 ◽  
Vol 38 ◽  
pp. 159-171 ◽  
Author(s):  
P.H. Thomas ◽  
M.L. Bullen ◽  
J.G. Quintiere ◽  
B.J. McCaffrey
Keyword(s):  
Fire Behavior ◽  
In Fire

Changes in fire behavior caused by fire exclusion and fuel build-up vary with topography in California montane forests, USA

2022 ◽  
Vol 304 ◽  
pp. 114255
Author(s):  
Catherine Airey-Lauvaux ◽  
Andrew D. Pierce ◽  
Carl N. Skinner ◽  
Alan H. Taylor
Keyword(s):  
Fire Behavior ◽  
Montane Forests ◽  
Fire Exclusion ◽  
In Fire

Numerical Analysis of Fire Behavior of a Large Space Pre-Stressed Steel Structure under Fire

2011 ◽  
Vol 71-78 ◽  
pp. 3729-3732
Author(s):  
Ming Zhou ◽  
Zhi Guo Xie ◽  
Xin Tang Wang
Keyword(s):  
Numerical Analysis ◽  
Fire Behavior ◽  
Thermal Response ◽  
Structural Response ◽  
Steel Structure ◽  
Large Space ◽  
Fire Source ◽  
Lattice Shell ◽  
In Fire ◽  
Influence Degree

The computational model of numerical analysis of a suspended pre-stressed steel reticulated shell subjected to fire load is established with using the software Marc. Based on the model presented here, numerical analysis of thermal response and structural response of the pre-stressed steel structure are computed. The different space height and different rise-span ratio are considered for analysis of response temperature, displacements and stresses of the pre-stressed lattice shell under fire for one fire source. It is also shown that displacement of the node right above the inner cable is the maximum among the four nodes presented here as the fire source is located at the position right below the second-ring cable of the structure. It is concluded that the influence degree of space height of the structure on the fire response of the structure is not great, but rise-span ratio has obvious and great effect on displacements and stresses of the pre-stressed steel structure with large span in fire.

scholarly journals Interpersonal dynamics and multidisciplinary teamwork

2009 ◽  
Vol 15 (6) ◽  
pp. 462-469 ◽  
Author(s):  
David Reiss ◽  
Gabriel Kirtchuk
Keyword(s):  
Multidisciplinary Team ◽  
Team Member ◽  
Full Range ◽  
Relationship Patterns ◽  
Interpersonal Dynamics ◽  
Therapeutic Modalities ◽  
The Past ◽  
Effective Interventions ◽  
Insight Into ◽  
Multidisciplinary Teamwork

SummaryAnalysing interpersonal dynamics is an approach through which the multidisciplinary team can develop a shared understanding of their patients. This empirically based method provides an insight into repeated patterns of dysfunctional behaviour, which not only have been evident in the past, but are currently having an impact on the patient's relationships with caring staff. The technique is accessible to any team member with only minimal training required. It provides the team with a coherent map of the patient's relationship patterns that underpins the formulation of an effective strategy for care. The multidisciplinary team is then able to work towards shared goals, supporting all members in their provision of effective interventions within the full range of therapeutic modalities. The approach promotes positive staff–patient interactions and provides an additional dimension to the assessment and management of risk.

Modeling on n-Heptane Pool Fire Behavior in an Altitude Chamber

2013 ◽  
Author(s):  
Quanyi Liu ◽  
Wei Yao ◽  
Jiusheng Yin ◽  
Rui Yang ◽  
Hui Zhang
Keyword(s):  
High Altitude ◽  
Burning Rate ◽  
Pressure Effect ◽  
Fire Behavior ◽  
Low Pressure ◽  
Pool Fire ◽  
Low Oxygen ◽  
Fire Plume ◽  
Plume Temperature ◽  
Modeling Data

Airplane as one of the important transport vehicles in our life, its safety problem related to in-flight fire has attracted a wide-spread attention. The combustion behavior of the cabin fire in flight shows some special characteristics because of the high-altitude environment with low-pressure and low oxygen concentration. A low-pressure chamber of size 2 m×3 m×2 m has been built to simulate high-altitude environments, where multiple static pressures for pool fire tests can be configured in the range between standard atmospheric pressure 101.3KPa and 30KPa. Two different sizes of pool fires were tested. Then corresponding modeling were conducted by a LES code FDS V5.5 to examine the mechanism of pressure effect on the n-Heptane pool fire behavior. The burning of liquid fuel was modeled by a Clausius-Clapeyron relation based liquid pyrolysis model. The modeling data was validated against the experimental measurements. The mass burning rate of free-burning pool fire decreases with the decreasing of pressure, which was observed from the modeling to be due to the reduction of flame heat feedback to the fuel surface. Under low pressure, the fire plume temperature increases for the same burning rate. The mechanism of pressure effect on fire behavior was analyzed based on the modeling data.

Properties and Types of Integration Mechanisms

1994 ◽  
Author(s):  
Alan W. Brown ◽  
David J. Carney ◽  
Edwin J. Morris ◽  
Dennis B. Smith ◽  
Paul F. Zarrella
Keyword(s):  
Full Range ◽  
Central Theme ◽  
Environment Design ◽  
Conceptual Approach ◽  
Bottom Line ◽  
Discussion Section ◽  
Integration Mechanisms ◽  
Definition Of ◽  
Insight Into ◽  
Control Integration

A central theme of this book is the three-level approach to CASE environment design and construction that distinguishes conceptual issues (the services) from implementation issues (the mechanisms) and stresses the need for a design context (the process) that the CASE environment must support. Previous chapters have discussed this theme, as well as provided insight into a conceptual model that identifies and classifies the services that might be found in a CASE environment. However, regardless of the service model or conceptual approach selected, environment builders must eventually face the bottom-line decision of how to actually carry out tool integration. The choices they face in terms of potential mechanisms are numerous and include a full range of selections that provide varying degrees of effort and integrated capability. In this chapter, we first consider the properties of integration by continuing the discussion of integration as a relationship (see Section 2.2). In this discussion (Section 5.2), we highlight properties that are addressed by various integration mechanisms. Later sections of this chapter focus on the specific relationship between two particular classes of integrating mechanisms: those based on the sharing or transfer of data between tools (data integration), and those based on synchronization and communication between tools (control integration). In Section 2.2 we introduced the concept put forward by Thomas and Nejmeh that integration can be considered by defining the properties required of the relationships between different environment components. Their definition of integration is exclusively a conceptual view, and is independent of the particular technology being used to implement that integration.

Nano-sized nickel catalyst for deep hydrogenation of lignin monomers and first-principles insight into the catalyst preparation

2017 ◽  
Vol 5 (8) ◽  
pp. 3948-3965 ◽  
Author(s):  
Shi-Chao Qi ◽  
Lu Zhang ◽  
Hisahiro Einaga ◽  
Shinji Kudo ◽  
Koyo Norinaga ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
First Principles ◽  
Density Functional ◽  
Full Range ◽  
Catalyst Preparation ◽  
Ni Catalyst ◽  
Borohydride Reduction ◽  
Functional Theory ◽  
Pyridine Complex ◽  
Insight Into

A type of nano-sized Ni catalyst supported by ZSM-5 zeolite for the deep hydrogenation of lignin monomers is prepared by borohydride reduction of a Ni2+–pyridine complex in ethanol. The mechanism of the borohydride reduction over the full range from Ni2+ to Ni0 is calculated by applying density functional theory.

scholarly journals The Impact of Fuel Treatments on Wildfire Behavior in North American Boreal Fuels: A Simulation Study Using FIRETEC

Fire ◽  
2020 ◽  
Vol 3 (2) ◽  
pp. 18 ◽  
Author(s):  
Ginny Marshall ◽  
Dan Thompson ◽  
Kerry Anderson ◽  
Brian Simpson ◽  
Rodman Linn ◽  
...  
Keyword(s):  
Black Spruce ◽  
Treatment Options ◽  
Fire Behavior ◽  
Fire Spread ◽  
Natural Forests ◽  
Spread Rate ◽  
Multiple Components ◽  
In Fire ◽  
The Impact ◽  
Common Tree

Current methods of predicting fire spread in Canadian forests are suited to large wildfires that spread through natural forests. Recently, the use of mechanical and thinning treatments of forests in the wildland-urban interface of Canada has increased. To assist in community wildfire protection planning in forests not covered by existing operational fire spread models, we use FIRETEC to simulate fire spread in lowland black spruce fuel structures, the most common tree stand in Canada. The simulated treatments included the mechanical mulching of strips, and larger, irregularly shaped areas. In all cases, the removal of fuel by mulch strips broke up the fuels, but also caused wind speed increases, so little decrease in fire spread rate was modelled. For large irregular clearings, the fire spread slowly through the mulched wood chips, and large decreases in fire spread and intensity were simulated. Furthermore, some treatments in the black spruce forest were found to be effective in decreasing the distance and/or density of firebrands. The simulations conducted can be used alongside experimental fires and documented wildfires to examine the effectiveness of differing fuel treatment options to alter multiple components of fire behavior.

CO2 effect on the pH of compacted bentonite buffer on the laboratory scale

Clay Minerals ◽  
2013 ◽  
Vol 48 (2) ◽  
pp. 277-284 ◽  
Author(s):  
A. Itäla ◽  
J. Järvinen ◽  
A. Muurinen
Keyword(s):  
Partial Pressure ◽  
Spent Nuclear Fuel ◽  
Buffering Capacity ◽  
Test Cases ◽  
Experimental Setup ◽  
Atmospheric Conditions ◽  
Compacted Bentonite ◽  
Bentonite Buffer ◽  
Insight Into

AbstractDisposal of Finnish spent nuclear fuel is planned to be based on the KBS-3 repository concept. The role of the bentonite buffer in this concept is essential, and thus the behaviour of the bentonite has to be known. The experiments in this paper concentrated on providing information about the effects of carbon dioxide CO2(g) partial pressure on compacted sodium bentonite, giving an insight into the buffering capacity. The experimental setup consisted of a hermetic box which had a CO2-adjusted atmosphere, and the bentonite was in contact with this atmosphere through water reservoirs. The results indicated that it is possible to measure online the changing pH in the porewater inside compacted bentonite using IrOx electrodes. It was found that the pH fell if the CO2 partial pressure increased above atmospheric conditions. The experimental results indicated a greater fall in pH than in our model in the test cases where CO2 was present. The pH in the experiment with 0 PCO2 remained nearly constant throughout the 5 month period. On the other hand, the pH dropped to near 6 with 0.3 PCO2 and to 5.5 with 1 PCO2.

Fire Protection of High-Performance Concrete Using Protective Lining

2011 ◽  
Vol 82 ◽  
pp. 758-763
Author(s):  
Eike Wolfram Klingsch ◽  
Andrea Frangi ◽  
Mario Fontana
Keyword(s):  
High Performance ◽  
Input Data ◽  
High Performance Concrete ◽  
Fire Behavior ◽  
Explosive Spalling ◽  
Protective Lining ◽  
In Fire ◽  
Concrete Elements ◽  
Basic Input ◽  
Fire Design

The paper presents results of experimental and numerical analyses on the fire behavior of concrete elements protected by sprayed protective linings. Particular attention is given to high- (HPC) and ultrahigh performance concrete (UHPC), as HPC and UHPC tend to exhibit explosive spalling in fire due to low porosity. The results provide basic input data for the development of simplified rules for the fire design of concrete structures protected by sprayed protective linings.

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