The document summarizes Michael Gollner's PhD defense on studies of upward flame spread. It discusses three parts of his research: 1) Flame spread over corrugated cardboard, where he found the flame height grew slower than theories predicted due to the curled structure of the cardboard altering the boundary layer. 2) Inclined flame spread, where experiments showed spread rate depends on angle and is fastest between 0-30 degrees. 3) Estimating heat flux profiles and radiant flux for inclined surfaces, finding radiant contribution is significant. The work improves understanding of upward flame spread over solid fuels.
Pathways to Building Fire Spread in the Wildland-Urban InterfaceMichael Gollner
Presentation from Michael Gollner at the University of Maryland at the NFPA Webinar on Pathways to Building Fire Spread in the Wildland-Urban Interface on April 21, 2015. Project sponsored by the NFPA Fire Protection Research Foundation
Pathways to Building Fire Spread in the Wildland-Urban InterfaceMichael Gollner
Presentation from Michael Gollner at the University of Maryland at the NFPA Webinar on Pathways to Building Fire Spread in the Wildland-Urban Interface on April 21, 2015. Project sponsored by the NFPA Fire Protection Research Foundation
The French Revolution, which began in 1789, was a period of radical social and political upheaval in France. It marked the decline of absolute monarchies, the rise of secular and democratic republics, and the eventual rise of Napoleon Bonaparte. This revolutionary period is crucial in understanding the transition from feudalism to modernity in Europe.
For more information, visit-www.vavaclasses.com
A Strategic Approach: GenAI in EducationPeter Windle
Artificial Intelligence (AI) technologies such as Generative AI, Image Generators and Large Language Models have had a dramatic impact on teaching, learning and assessment over the past 18 months. The most immediate threat AI posed was to Academic Integrity with Higher Education Institutes (HEIs) focusing their efforts on combating the use of GenAI in assessment. Guidelines were developed for staff and students, policies put in place too. Innovative educators have forged paths in the use of Generative AI for teaching, learning and assessments leading to pockets of transformation springing up across HEIs, often with little or no top-down guidance, support or direction.
This Gasta posits a strategic approach to integrating AI into HEIs to prepare staff, students and the curriculum for an evolving world and workplace. We will highlight the advantages of working with these technologies beyond the realm of teaching, learning and assessment by considering prompt engineering skills, industry impact, curriculum changes, and the need for staff upskilling. In contrast, not engaging strategically with Generative AI poses risks, including falling behind peers, missed opportunities and failing to ensure our graduates remain employable. The rapid evolution of AI technologies necessitates a proactive and strategic approach if we are to remain relevant.
Model Attribute Check Company Auto PropertyCeline George
In Odoo, the multi-company feature allows you to manage multiple companies within a single Odoo database instance. Each company can have its own configurations while still sharing common resources such as products, customers, and suppliers.
June 3, 2024 Anti-Semitism Letter Sent to MIT President Kornbluth and MIT Cor...Levi Shapiro
Letter from the Congress of the United States regarding Anti-Semitism sent June 3rd to MIT President Sally Kornbluth, MIT Corp Chair, Mark Gorenberg
Dear Dr. Kornbluth and Mr. Gorenberg,
The US House of Representatives is deeply concerned by ongoing and pervasive acts of antisemitic
harassment and intimidation at the Massachusetts Institute of Technology (MIT). Failing to act decisively to ensure a safe learning environment for all students would be a grave dereliction of your responsibilities as President of MIT and Chair of the MIT Corporation.
This Congress will not stand idly by and allow an environment hostile to Jewish students to persist. The House believes that your institution is in violation of Title VI of the Civil Rights Act, and the inability or
unwillingness to rectify this violation through action requires accountability.
Postsecondary education is a unique opportunity for students to learn and have their ideas and beliefs challenged. However, universities receiving hundreds of millions of federal funds annually have denied
students that opportunity and have been hijacked to become venues for the promotion of terrorism, antisemitic harassment and intimidation, unlawful encampments, and in some cases, assaults and riots.
The House of Representatives will not countenance the use of federal funds to indoctrinate students into hateful, antisemitic, anti-American supporters of terrorism. Investigations into campus antisemitism by the Committee on Education and the Workforce and the Committee on Ways and Means have been expanded into a Congress-wide probe across all relevant jurisdictions to address this national crisis. The undersigned Committees will conduct oversight into the use of federal funds at MIT and its learning environment under authorities granted to each Committee.
• The Committee on Education and the Workforce has been investigating your institution since December 7, 2023. The Committee has broad jurisdiction over postsecondary education, including its compliance with Title VI of the Civil Rights Act, campus safety concerns over disruptions to the learning environment, and the awarding of federal student aid under the Higher Education Act.
• The Committee on Oversight and Accountability is investigating the sources of funding and other support flowing to groups espousing pro-Hamas propaganda and engaged in antisemitic harassment and intimidation of students. The Committee on Oversight and Accountability is the principal oversight committee of the US House of Representatives and has broad authority to investigate “any matter” at “any time” under House Rule X.
• The Committee on Ways and Means has been investigating several universities since November 15, 2023, when the Committee held a hearing entitled From Ivory Towers to Dark Corners: Investigating the Nexus Between Antisemitism, Tax-Exempt Universities, and Terror Financing. The Committee followed the hearing with letters to those institutions on January 10, 202
2024.06.01 Introducing a competency framework for languag learning materials ...Sandy Millin
http://sandymillin.wordpress.com/iateflwebinar2024
Published classroom materials form the basis of syllabuses, drive teacher professional development, and have a potentially huge influence on learners, teachers and education systems. All teachers also create their own materials, whether a few sentences on a blackboard, a highly-structured fully-realised online course, or anything in between. Despite this, the knowledge and skills needed to create effective language learning materials are rarely part of teacher training, and are mostly learnt by trial and error.
Knowledge and skills frameworks, generally called competency frameworks, for ELT teachers, trainers and managers have existed for a few years now. However, until I created one for my MA dissertation, there wasn’t one drawing together what we need to know and do to be able to effectively produce language learning materials.
This webinar will introduce you to my framework, highlighting the key competencies I identified from my research. It will also show how anybody involved in language teaching (any language, not just English!), teacher training, managing schools or developing language learning materials can benefit from using the framework.
Introduction to AI for Nonprofits with Tapp NetworkTechSoup
Dive into the world of AI! Experts Jon Hill and Tareq Monaur will guide you through AI's role in enhancing nonprofit websites and basic marketing strategies, making it easy to understand and apply.
2024 State of Marketing Report – by HubspotMarius Sescu
https://www.hubspot.com/state-of-marketing
· Scaling relationships and proving ROI
· Social media is the place for search, sales, and service
· Authentic influencer partnerships fuel brand growth
· The strongest connections happen via call, click, chat, and camera.
· Time saved with AI leads to more creative work
· Seeking: A single source of truth
· TLDR; Get on social, try AI, and align your systems.
· More human marketing, powered by robots
ChatGPT is a revolutionary addition to the world since its introduction in 2022. A big shift in the sector of information gathering and processing happened because of this chatbot. What is the story of ChatGPT? How is the bot responding to prompts and generating contents? Swipe through these slides prepared by Expeed Software, a web development company regarding the development and technical intricacies of ChatGPT!
The French Revolution, which began in 1789, was a period of radical social and political upheaval in France. It marked the decline of absolute monarchies, the rise of secular and democratic republics, and the eventual rise of Napoleon Bonaparte. This revolutionary period is crucial in understanding the transition from feudalism to modernity in Europe.
For more information, visit-www.vavaclasses.com
A Strategic Approach: GenAI in EducationPeter Windle
Artificial Intelligence (AI) technologies such as Generative AI, Image Generators and Large Language Models have had a dramatic impact on teaching, learning and assessment over the past 18 months. The most immediate threat AI posed was to Academic Integrity with Higher Education Institutes (HEIs) focusing their efforts on combating the use of GenAI in assessment. Guidelines were developed for staff and students, policies put in place too. Innovative educators have forged paths in the use of Generative AI for teaching, learning and assessments leading to pockets of transformation springing up across HEIs, often with little or no top-down guidance, support or direction.
This Gasta posits a strategic approach to integrating AI into HEIs to prepare staff, students and the curriculum for an evolving world and workplace. We will highlight the advantages of working with these technologies beyond the realm of teaching, learning and assessment by considering prompt engineering skills, industry impact, curriculum changes, and the need for staff upskilling. In contrast, not engaging strategically with Generative AI poses risks, including falling behind peers, missed opportunities and failing to ensure our graduates remain employable. The rapid evolution of AI technologies necessitates a proactive and strategic approach if we are to remain relevant.
Model Attribute Check Company Auto PropertyCeline George
In Odoo, the multi-company feature allows you to manage multiple companies within a single Odoo database instance. Each company can have its own configurations while still sharing common resources such as products, customers, and suppliers.
June 3, 2024 Anti-Semitism Letter Sent to MIT President Kornbluth and MIT Cor...Levi Shapiro
Letter from the Congress of the United States regarding Anti-Semitism sent June 3rd to MIT President Sally Kornbluth, MIT Corp Chair, Mark Gorenberg
Dear Dr. Kornbluth and Mr. Gorenberg,
The US House of Representatives is deeply concerned by ongoing and pervasive acts of antisemitic
harassment and intimidation at the Massachusetts Institute of Technology (MIT). Failing to act decisively to ensure a safe learning environment for all students would be a grave dereliction of your responsibilities as President of MIT and Chair of the MIT Corporation.
This Congress will not stand idly by and allow an environment hostile to Jewish students to persist. The House believes that your institution is in violation of Title VI of the Civil Rights Act, and the inability or
unwillingness to rectify this violation through action requires accountability.
Postsecondary education is a unique opportunity for students to learn and have their ideas and beliefs challenged. However, universities receiving hundreds of millions of federal funds annually have denied
students that opportunity and have been hijacked to become venues for the promotion of terrorism, antisemitic harassment and intimidation, unlawful encampments, and in some cases, assaults and riots.
The House of Representatives will not countenance the use of federal funds to indoctrinate students into hateful, antisemitic, anti-American supporters of terrorism. Investigations into campus antisemitism by the Committee on Education and the Workforce and the Committee on Ways and Means have been expanded into a Congress-wide probe across all relevant jurisdictions to address this national crisis. The undersigned Committees will conduct oversight into the use of federal funds at MIT and its learning environment under authorities granted to each Committee.
• The Committee on Education and the Workforce has been investigating your institution since December 7, 2023. The Committee has broad jurisdiction over postsecondary education, including its compliance with Title VI of the Civil Rights Act, campus safety concerns over disruptions to the learning environment, and the awarding of federal student aid under the Higher Education Act.
• The Committee on Oversight and Accountability is investigating the sources of funding and other support flowing to groups espousing pro-Hamas propaganda and engaged in antisemitic harassment and intimidation of students. The Committee on Oversight and Accountability is the principal oversight committee of the US House of Representatives and has broad authority to investigate “any matter” at “any time” under House Rule X.
• The Committee on Ways and Means has been investigating several universities since November 15, 2023, when the Committee held a hearing entitled From Ivory Towers to Dark Corners: Investigating the Nexus Between Antisemitism, Tax-Exempt Universities, and Terror Financing. The Committee followed the hearing with letters to those institutions on January 10, 202
2024.06.01 Introducing a competency framework for languag learning materials ...Sandy Millin
http://sandymillin.wordpress.com/iateflwebinar2024
Published classroom materials form the basis of syllabuses, drive teacher professional development, and have a potentially huge influence on learners, teachers and education systems. All teachers also create their own materials, whether a few sentences on a blackboard, a highly-structured fully-realised online course, or anything in between. Despite this, the knowledge and skills needed to create effective language learning materials are rarely part of teacher training, and are mostly learnt by trial and error.
Knowledge and skills frameworks, generally called competency frameworks, for ELT teachers, trainers and managers have existed for a few years now. However, until I created one for my MA dissertation, there wasn’t one drawing together what we need to know and do to be able to effectively produce language learning materials.
This webinar will introduce you to my framework, highlighting the key competencies I identified from my research. It will also show how anybody involved in language teaching (any language, not just English!), teacher training, managing schools or developing language learning materials can benefit from using the framework.
Introduction to AI for Nonprofits with Tapp NetworkTechSoup
Dive into the world of AI! Experts Jon Hill and Tareq Monaur will guide you through AI's role in enhancing nonprofit websites and basic marketing strategies, making it easy to understand and apply.
2024 State of Marketing Report – by HubspotMarius Sescu
https://www.hubspot.com/state-of-marketing
· Scaling relationships and proving ROI
· Social media is the place for search, sales, and service
· Authentic influencer partnerships fuel brand growth
· The strongest connections happen via call, click, chat, and camera.
· Time saved with AI leads to more creative work
· Seeking: A single source of truth
· TLDR; Get on social, try AI, and align your systems.
· More human marketing, powered by robots
ChatGPT is a revolutionary addition to the world since its introduction in 2022. A big shift in the sector of information gathering and processing happened because of this chatbot. What is the story of ChatGPT? How is the bot responding to prompts and generating contents? Swipe through these slides prepared by Expeed Software, a web development company regarding the development and technical intricacies of ChatGPT!
Product Design Trends in 2024 | Teenage EngineeringsPixeldarts
The realm of product design is a constantly changing environment where technology and style intersect. Every year introduces fresh challenges and exciting trends that mold the future of this captivating art form. In this piece, we delve into the significant trends set to influence the look and functionality of product design in the year 2024.
How Race, Age and Gender Shape Attitudes Towards Mental HealthThinkNow
Mental health has been in the news quite a bit lately. Dozens of U.S. states are currently suing Meta for contributing to the youth mental health crisis by inserting addictive features into their products, while the U.S. Surgeon General is touring the nation to bring awareness to the growing epidemic of loneliness and isolation. The country has endured periods of low national morale, such as in the 1970s when high inflation and the energy crisis worsened public sentiment following the Vietnam War. The current mood, however, feels different. Gallup recently reported that national mental health is at an all-time low, with few bright spots to lift spirits.
To better understand how Americans are feeling and their attitudes towards mental health in general, ThinkNow conducted a nationally representative quantitative survey of 1,500 respondents and found some interesting differences among ethnic, age and gender groups.
Technology
For example, 52% agree that technology and social media have a negative impact on mental health, but when broken out by race, 61% of Whites felt technology had a negative effect, and only 48% of Hispanics thought it did.
While technology has helped us keep in touch with friends and family in faraway places, it appears to have degraded our ability to connect in person. Staying connected online is a double-edged sword since the same news feed that brings us pictures of the grandkids and fluffy kittens also feeds us news about the wars in Israel and Ukraine, the dysfunction in Washington, the latest mass shooting and the climate crisis.
Hispanics may have a built-in defense against the isolation technology breeds, owing to their large, multigenerational households, strong social support systems, and tendency to use social media to stay connected with relatives abroad.
Age and Gender
When asked how individuals rate their mental health, men rate it higher than women by 11 percentage points, and Baby Boomers rank it highest at 83%, saying it’s good or excellent vs. 57% of Gen Z saying the same.
Gen Z spends the most amount of time on social media, so the notion that social media negatively affects mental health appears to be correlated. Unfortunately, Gen Z is also the generation that’s least comfortable discussing mental health concerns with healthcare professionals. Only 40% of them state they’re comfortable discussing their issues with a professional compared to 60% of Millennials and 65% of Boomers.
Race Affects Attitudes
As seen in previous research conducted by ThinkNow, Asian Americans lag other groups when it comes to awareness of mental health issues. Twenty-four percent of Asian Americans believe that having a mental health issue is a sign of weakness compared to the 16% average for all groups. Asians are also considerably less likely to be aware of mental health services in their communities (42% vs. 55%) and most likely to seek out information on social media (51% vs. 35%).
AI Trends in Creative Operations 2024 by Artwork Flow.pdfmarketingartwork
This article is all about what AI trends will emerge in the field of creative operations in 2024. All the marketers and brand builders should be aware of these trends for their further use and save themselves some time!
A report by thenetworkone and Kurio.
The contributing experts and agencies are (in an alphabetical order): Sylwia Rytel, Social Media Supervisor, 180heartbeats + JUNG v MATT (PL), Sharlene Jenner, Vice President - Director of Engagement Strategy, Abelson Taylor (USA), Alex Casanovas, Digital Director, Atrevia (ES), Dora Beilin, Senior Social Strategist, Barrett Hoffher (USA), Min Seo, Campaign Director, Brand New Agency (KR), Deshé M. Gully, Associate Strategist, Day One Agency (USA), Francesca Trevisan, Strategist, Different (IT), Trevor Crossman, CX and Digital Transformation Director; Olivia Hussey, Strategic Planner; Simi Srinarula, Social Media Manager, The Hallway (AUS), James Hebbert, Managing Director, Hylink (CN / UK), Mundy Álvarez, Planning Director; Pedro Rojas, Social Media Manager; Pancho González, CCO, Inbrax (CH), Oana Oprea, Head of Digital Planning, Jam Session Agency (RO), Amy Bottrill, Social Account Director, Launch (UK), Gaby Arriaga, Founder, Leonardo1452 (MX), Shantesh S Row, Creative Director, Liwa (UAE), Rajesh Mehta, Chief Strategy Officer; Dhruv Gaur, Digital Planning Lead; Leonie Mergulhao, Account Supervisor - Social Media & PR, Medulla (IN), Aurelija Plioplytė, Head of Digital & Social, Not Perfect (LI), Daiana Khaidargaliyeva, Account Manager, Osaka Labs (UK / USA), Stefanie Söhnchen, Vice President Digital, PIABO Communications (DE), Elisabeth Winiartati, Managing Consultant, Head of Global Integrated Communications; Lydia Aprina, Account Manager, Integrated Marketing and Communications; Nita Prabowo, Account Manager, Integrated Marketing and Communications; Okhi, Web Developer, PNTR Group (ID), Kei Obusan, Insights Director; Daffi Ranandi, Insights Manager, Radarr (SG), Gautam Reghunath, Co-founder & CEO, Talented (IN), Donagh Humphreys, Head of Social and Digital Innovation, THINKHOUSE (IRE), Sarah Yim, Strategy Director, Zulu Alpha Kilo (CA).
Trends In Paid Search: Navigating The Digital Landscape In 2024Search Engine Journal
The search marketing landscape is evolving rapidly with new technologies, and professionals, like you, rely on innovative paid search strategies to meet changing demands.
It’s important that you’re ready to implement new strategies in 2024.
Check this out and learn the top trends in paid search advertising that are expected to gain traction, so you can drive higher ROI more efficiently in 2024.
You’ll learn:
- The latest trends in AI and automation, and what this means for an evolving paid search ecosystem.
- New developments in privacy and data regulation.
- Emerging ad formats that are expected to make an impact next year.
Watch Sreekant Lanka from iQuanti and Irina Klein from OneMain Financial as they dive into the future of paid search and explore the trends, strategies, and technologies that will shape the search marketing landscape.
If you’re looking to assess your paid search strategy and design an industry-aligned plan for 2024, then this webinar is for you.
5 Public speaking tips from TED - Visualized summarySpeakerHub
From their humble beginnings in 1984, TED has grown into the world’s most powerful amplifier for speakers and thought-leaders to share their ideas. They have over 2,400 filmed talks (not including the 30,000+ TEDx videos) freely available online, and have hosted over 17,500 events around the world.
With over one billion views in a year, it’s no wonder that so many speakers are looking to TED for ideas on how to share their message more effectively.
The article “5 Public-Speaking Tips TED Gives Its Speakers”, by Carmine Gallo for Forbes, gives speakers five practical ways to connect with their audience, and effectively share their ideas on stage.
Whether you are gearing up to get on a TED stage yourself, or just want to master the skills that so many of their speakers possess, these tips and quotes from Chris Anderson, the TED Talks Curator, will encourage you to make the most impactful impression on your audience.
See the full article and more summaries like this on SpeakerHub here: https://speakerhub.com/blog/5-presentation-tips-ted-gives-its-speakers
See the original article on Forbes here:
http://www.forbes.com/forbes/welcome/?toURL=http://www.forbes.com/sites/carminegallo/2016/05/06/5-public-speaking-tips-ted-gives-its-speakers/&refURL=&referrer=#5c07a8221d9b
ChatGPT and the Future of Work - Clark Boyd Clark Boyd
Everyone is in agreement that ChatGPT (and other generative AI tools) will shape the future of work. Yet there is little consensus on exactly how, when, and to what extent this technology will change our world.
Businesses that extract maximum value from ChatGPT will use it as a collaborative tool for everything from brainstorming to technical maintenance.
For individuals, now is the time to pinpoint the skills the future professional will need to thrive in the AI age.
Check out this presentation to understand what ChatGPT is, how it will shape the future of work, and how you can prepare to take advantage.
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The six step guide to practical project managementMindGenius
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If you think managing projects is too difficult, think again.
We’ve stripped back project management processes to the
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“If you’re looking for some real-world guidance, then The Six Step Guide to Practical Project Management will help.”
Dr Andrew Makar, Tactical Project Management
Beginners Guide to TikTok for Search - Rachel Pearson - We are Tilt __ Bright...
Gollner PhD Dissertation Defense: "Studies on Upward Flame Spread"
1. Studies on Upward Flame Spread
PhD Defense of
Michael J. Gollner
University of California, San Diego
Professor Forman A. Williams, Chair
July 24, 2012 1
May 21, 2012 PhD Defense: Studies on Upward Flame Spread 1
2. Motivation
Flame Spread Theory
1. Corrugated Cardboard Flame Spread
2. Inclined Flame Spread
3. Discrete Fuel Flame Spread
Conclusions
July 24, 2012
Acknowledgements 2
May 21, 2012 PhD Defense: Studies on Upward Flame Spread 2
3. Why Study Fire?
NFPA, 2009
July 24, 2012 3
$362 billion, or 2.5 % of the US GDP
May 21, 2012 PhD Defense: Studies on Upward Flame Spread 3
4. Motivation
Industrial Fires The Built Environment
July 24, 2012 4
Wildfires Cable Trays
May 21, 2012 PhD Defense: Studies on Upward Flame Spread 4
5. Review:
UPWARD FLAME SPREAD
THEORY
July 24, 2012 5
May 21, 2012 PhD Defense: Studies on Upward Flame Spread 5
6. Upward Flame Spread
Thermal Boundary Layer
g
Excess
SOLID FUEL
1. Thermal Boundary Layer Pyrolyzate
2. Heat Flux to the Fuel yf xf Flame Height
3. Buoyancy
q f ( x, t )
Vp
y xp Pyrolysis Height
July 24, 2012 qp
6
x
m f H c ~ HRR
Diffusion Flame
May 21, 2012 PhD Defense: Studies on Upward Flame Spread 6
7. Flame Spread Models
q Constant
q Constant
July 24, 2012 One of few models with q(x) [1]
7
1. Sibulkin and Kim, Comb. Sci. Tech. vol. 17, 1977
May 21, 2012 PhD Defense: Studies on Upward Flame Spread 7
8. Results of Upward Spread Theories
2
Annamalai & Sibulkin: x f ~ A1 ( B1 t ) (Laminar)
t
Saito, Quintiere, Williams: x f ~ A2e (Turbulent)
Sibulkin & Kim: x f ~ A3t 2 (Laminar)
x f ~ B3e t (Turbulent)
Where A, B, and α are constants
NOTE: All results for non-charring fuels.
July 24, 2012 8
1. Annamalai, K. and Sibulkin, M., Combust. Sci. Tech., 1979, vol. 19, pp. 167-183.
2. Saito, J.G. Quintiere, and F.A. Williams, Fire Safety Science, vol.1, 1985, pp. 75-86.
3. Sibulkin and Kim, Comb. Sci. Tech. vol. 17, 1977
May 21, 2012 PhD Defense: Studies on Upward Flame Spread 8
9. Industrial Fires
Part I:
UPWARD FLAME SPREAD OVER
CORRUGATED CARDBOARD
July 24, 2012 9
May 15, 2012
21, 2012 BuoyancyDefense: Studies onBehavior Flame Spread
PhD Effects on Burning Upward and Flame Spread 9
10. Cardboard Spread Experiments
• Uniform ignition at
base by Heptane wick
• Insulated board above
sample
• Sample filled with
plastics, but this study only addresses the
behavior before these plastics ignite
July 24, 2012 10
Gollner, M.J., Overholt, K., et al., Fire Saf. J., 46(6), 2011, pp. 305-316.
Overholt, K., Gollner, M.J, et al., Fire Saf. J., 46(6), 2011, pp 317-329.
Gollner, M.J., Williams, F.A., and Rangwala, A.S. Combust. Flame, 158(7), 2011.
May 15, 2012
21, 2012 BuoyancyDefense: Studies onBehavior Flame Spread
PhD Effects on Burning Upward and Flame Spread 10
11. Flame Height Observations
x f ~ t 3/2 fits x f ,max
50
Observed Trend
40
Why does the pyrolysis front and flame height x f ,avg
Height (cm)
30
grow SLOWER than what current theories
would predict? x p ,avg
20
10
0
0
July 24, 2012 10 20 30 40 50
11
Time from Ignition (s)
Gollner, M.J., Williams, F.A., and Rangwala, A.S. Combust. Flame, 158(7), 2011.
May 15, 2012
21, 2012 BuoyancyDefense: Studies onBehavior Flame Spread
PhD Effects on Burning Upward and Flame Spread 11
21. Boundary-Layer Extension
Traditional Boundary Hypothesized Modified
Layer Boundary layer
y~x 1/4 y ~ x1/3
q ~ 1/ x1/4
q ~ 1/ x1/3
x
y
Curled
July 24, 2012 21
Cardboard
May 15, 2012 Buoyancy Effects on Burning Behavior and Flame Spread 21
22. How Would this Affect xp & xf?
Temperature of a thick fuel with time-dependent heat flux [1,2]:
t
1
q
T T0 dt
k c 0 t t
Assuming material pyrolyses at fixed Tp, substitute τ=t/t’, integral becomes a
constant dependent on material properties:
1
q t
I d
0 1
Assuming a new q(x) power-law variation based on boundary layer extension:
q C / x1/3
The time, t of arrival of pyrolysis front will obey:
xp At 3/2
Assuming
x f ~ m ~ x p , where m is the burning rate per unit width:
xf Bt 3/2
July 24, 2012 recover what was observed in experiments!
You 22
1. H.E. Mitler, Proc. Combust. Inst., 23 (1991), pp. 1715–1721
2. Conduction of heat in solids, Carslaw, H. S.; Jaeger, J. C. Oxford: Clarendon Press, 1959, 2nd ed.
May 15, 2012 Buoyancy Effects on Burning Behavior and Flame Spread 22
23. Corrugated Cardboard Applications
Early-stage ignition and spread
Rack storage test, UL Laboratories
HVLS Fan, NFPA FPRF Study
Photo Taken while at Schirmer Eng.
July 24, 2012 23
Tupperware Warehouse Fire (NFPA)
May 15, 2012 Buoyancy Effects on Burning Behavior and Flame Spread 23
24. The Built Environment Wildfires
Part II:
INCLINED FLAME SPREAD
July 24, 2012 24
May 21, 2012 PhD Defense: Studies on Upward Flame Spread 24
25. Burning & Spread over a Solid Fuel
g
y
July 24, 2012 25
x
May 21, 2012 PhD Defense: Studies on Upward Flame Spread 25
26. Burning & Spread over a Solid Fuel
• Modify Heat Flux Profiles
g
• Will Modify V p and m f
q ( x, t , )
q f ( x, t ) f ~ xn
yf
qp
Vp
mf
HcQ xf
y'
July 24, 2012 26
x' xp
May 21, 2012 PhD Defense: Studies on Upward Flame Spread 26
27. Experimental setup
July 24, 2012 27
May 21, 2012 PhD Defense: Studies on Upward Flame Spread 27
28. Effects of orientation
July 24, 2012 28
*Video is shown at 5 times actual speed
May 21, 2012 PhD Defense: Studies on Upward Flame Spread 28
29. 0.0
Spread Velocity
Spread Rate (cm/s)
0.0
0.0
0.09
0.0
0.08
Underside measurements
(-60 to 0 ) have not been 0.0
0.07 reported before
0.0
Spread Rate, Vp (cm/s)
0.06
0.05
The peak velocity appears
0.04
between 0 and -30
0.03
Vp (This study, w=10cm)
0.02 Pizzo (model)
Pizzo (exp, w=20cm)
0.01 Drydale and Macmillian (w=6cm)
Xie and DesJardin (model)
0
-60 -45 -30 0 30 45 60
Angle of Inclination,
July 24, 2012 29
1. Y. Pizzo, J.L. Consalvi, B. Porterie, Comb. Flame. 156 (2009) 1856-1859.
2. D. Drysdale, A. Macmillan. Fire Safety J. 18, no. 3 (1992): 245-254.
3. W. Xie, P. Desjardin, Comb. Flame. 156 (2009) 522-530.
May 21, 2012 PhD Defense: Studies on Upward Flame Spread 29
30. Mass-loss Rate per unit Area
Steady rates from larger gas
burner is qualitatively similar
Steady rates from smaller
PMMA samples are parabolic
Steady rates averaged 800-1000
seconds after uniform ignition
Spreading rates measured when
xp reaches top of sample
July 24, 2012 30
1. H. Ohtani, K. Ohta, Y. Uehara, Fire Mat. 18 (1991) 323-193.
2. de Ris, J, L. Orloff. Proc. Comb. Inst. 15 (1975) 175-182.
Burning of Inclined FuelStudies on Upward Flame Spread
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31. Radiant-Flux Estimates
July 24, 2012 31
Slide name - conference -
July 24, 2012 31
May 24, 2012
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location
Burning of Inclined Fuel Surfaces WSS/CI Spring Meeting ASU 31
31
32. Radiant-Flux Estimates
Total Heat Flux (estimated from
mass-loss rates)
Maximum heat flux in
combusting plume
Estimated radiant contribution
(from heat flux gauges)
qJuly 24,2012 m H p
p q rr 32
q rr Tp 4 6.1 kW/m2
Burning of Inclined FuelStudies on Upward Flame Spread
May 21, 2012
July 24, 2012 PhD Defense: Surfaces WSS/CI Spring Meeting ASU 32
33. Flame Standoff Distance
July 24, 2012 33
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33
34. Flame-Standoff Distance
July 24, 2012 34
Burning of Inclined FuelStudies on Upward Flame Spread
May 21, 2012
July 24, 2012 PhD Defense: Surfaces WSS/CI Spring Meeting ASU 34
35. Flame Shape
July 24, 2012 35
Burning of Inclined FuelStudies on Upward Flame Spread
May 21, 2012
July 24, 2012 PhD Defense: Surfaces WSS/CI Spring Meeting ASU 35
36. Width Effects
July 24, 2012 36
Burning of Inclined FuelStudies on Upward Flame Spread
May 21, 2012
July 24, 2012 PhD Defense: Surfaces WSS/CI Spring Meeting ASU 36
37. Heat-Flux Profiles
15
10
5
-60o
2
-45o
q 1 -30o
0o
0.5
30o
0.25 45o
60o
1.2 1.4 1.6 1.8 2 2.2
x / xp
July 24, 2012 37
n
Power-law fit:
q f ( x) A( x / x p )
Burning of Inclined FuelStudies on Upward Flame Spread
May 21, 2012
July 24, 2012 PhD Defense: Surfaces WSS/CI Spring Meeting ASU 37
38. Inclined Flame Spread & Burning
Flame Spread Steady Burning
0.09 10
0.08 9
Gas Burner, 65 cm [5]
2
0.07
8
Spread Rate, Vp Vp (cm/s)
0.06
Mass-loss Rate (g/m s)
Spread Rate, (cm/s)
7
0.05
0.09
6
0.04
0.08 PMMA, Steady Burning
5
0.03
0.07
Vp (This study, w=10cm)
4
0.02 Pizzo (model)
0.06
PMMA, Spreading
Spread Rate (cm/s)
Pizzo (exp, w=20cm)
0.01 Drydale and Macmillian (w=6cm) 3
0.05
Xie and DesJardin (model)
0
0.04
2
-60 -45 -30 0 30 45 60 -60 -45 -30 0 30 45 60
Angle of Inclination, θ
Angle of Inclination, of
Angle Inclination, θ
0.03
Vp (This Study, w=10cm)
0.02
Pizzo (Model)
Pizzo (Exp, w=20cm)
0.01
Drydale and Macmillian (w=6cm)
Xie and DesJardin (Model)
July -80 2012-40
0 24, -60 -20 0 20 40 60 80 38
Angle of Inclination,
1. Y. Pizzo, J.L. Consalvi, B. Porterie, Comb. Flame. 156 (2009) 1856-1859. 4. H. Ohtani, K. Ohta, Y. Uehara, Fire Mat. 18 (1991) 323-193.
2. D. Drysdale, A. Macmillan. Fire Safety J. 18, no. 3 (1992): 245-254. 5. de Ris, J, L. Orloff. Proc. Comb. Inst. 15 (1975) 175-182.
3. W. Xie, P. Desjardin, Comb. Flame. 156 (2009) 522-530.
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PhD Effects on Burning Upward and Flame Spread 38
39. Inclined Flame Spread Applications
Large, inclined atria ceiling
ASTM E108 (Roof Fire Test, Top)
Future KEPKO Headquarters
(Korea)
July 24, 2012 39
Flame spread on slopes ASTM E108 (Roof Fire Test, Bottom)
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PhD Effects on Burning Upward and Flame Spread 39
40. Cable Trays Industrial Fires Wildfires
Part III:
DISCRETE FUEL FLAME SPREAD
July 24, 2012 40
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40
41. Discrete Fuel Spread & Burning
July 24, 2012 41
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41
42. Matchstick Spread & Burning
Pyrolysis Spread Burnout Time
xp ~ t1.6 to t1.7
x p ~ t 3/2
S
xp ~ t
xp tb
(cm)
S 0
t (s) x (cm)
u ~ gx ~ Re ~ Nu
July 24, 2012 42
Gollner, M.J., Xie, Y., Lee, M., Nakamura, Y., and Rangwala,
A.S., 2012, In Press, Comb. Sci. Tech.
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42
43. Calculating Ignition Time for Spread
• Flame spread is a sequence of ignitions
• Matchsticks assumed to be thermally thin1, so
the pyrolysis or ignition time can be reduced
to tp s c p , s d (Tp
T )/q
• Simple heat transfer correlations can be used
to determine q for two limiting cases:
S 0 S 0
July 24, 2012 43
1Matchstick thickness
less than thermal thickness, lth ~ ks (Tig T ) / q
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43
44. Heat Transfer, S = 0
S 0
• Primarily convection-driven heat transfer from
burning matchsticks below to wall above2
• Correlation for flow over a wall can be used1
Nu x 059(Grx Pr)1/4
• Where Gr ( g (T T ) x ) / is the Grashof number,
x s
3 3
Pr / t is the Prandtl number and Nu d hd / k is
g
the Nusselt number
July 24, 2012 44
1.F. P. Incropera and D. P. DeWitt. Introduction to Heat Transfer, Fifth Edition. John Wiley & Sons, New York, 2002.
2. G. F. Carrier, F. E. Fendell, and M. F. Wolf., Combust. Sci. Technol., 75(1-3):3151, 1991.
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44
45. Heat Transfer, S > 0
S 0
• Primarily convection-driven heat transfer from
burning matchstick below to stick above
• Correlation for flow over a cylinder can be used [1]
Nu d 0.344Re0.56
d
• Assuming the buoyant velocity follows ug gx , the
Reynolds number, Re u d/ can be calculated d g g g
• The average rate of heat transfer, q can be calculated
from the Nusselt number for each matchstick
July 24, 2012 45
q h (Ts T )
1. F. A. Albini and E. D. Reinhardt. Int. J. Wildland Fire, 5(2):8191, 1995.
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45
46. Matchstick Spread & Burning
Pyrolysis Spread Burnout Time
xp ~ t1.6 to t1.7
x p ~ t 3/2
S 0
xp ~ t
xp tb
(cm)
S
t (s) x (cm)
u ~ gx ~ Re ~ Nu
• Predictions suggest the spread
process 24, 2012
July is dominated by convection 46
Gollner, M.J., Xie, Y., Lee, M., Nakamura, Y., and Rangwala,
A.S., 2012, In Press, Comb. Sci. Tech.
May 15, 2012
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Buoyancy Effects on BurningUpward and Flame Spread
PhD Effects on Burning Behavior and Spread 46
46
47. Burnout Time Prediction
• We again analyze two limiting cases, S 0 and S
• For S 0 , heating from the flame to the solid occurs
as conduction from the flame to the fuel surface:
q kg (Tf Ts ) / y f
• If the fuel is thermally thin and yf is uniform along
the side of the fuel, a balanced equation of energy is
tb Tf Ts c (Ts T )d
s p ,s H pd s
kg dt
0 yf 2
• Integrating and solving for the burnout time
yf s d [c p ,s (Ts T ) Hp]
tb
2k g (T f Ts )
S 0
July 24, 2012 47 47
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47
48. Burnout Time Prediction
• For S , we assume a match is nearly burning
free in the air
• Burning rate theory for a spherical fuel droplet
can be extended to a cylindrical geometry [1]
• Assuming a matchstick is nearly cylindrical with
initial radius ri d / 2 and unit length, the burning
rate becomes
d 2 drs
m ( s r )
s 2 rs s
m(rs ),
dt dt
Where rs is the radius of the cylinder at time t
July 24, 2012 48
1. C. K. Lee. Burning rate of fuel cylinders. Combust. Flame, 32:271276, 1978.
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48
49. Burnout Time Prediction
• The time necessary to deplete all fuel in the cylinder,
the burnout time is then
tb 2 rs s
tb dr .
0 (rs ) s
m
• Replacing m(r ) with the solution for the burning rate
s
k
over a cylinder fuel surface, c ln(1 B) ln(r / r ) , where
2
g
p, g
f s
1
B c p (T f Ts ) / H p and integrating the burnout time is
c
s p, g ln(rf / rs )ri 2
tb .
4k g ln(1 B)
• The standoff distance ratio is estimated from a
correlation:
0.75
ln(rf / rs ) 02(d / 2)
July 24, 2012 49
1. C. K. Lee. Burning rate of fuel cylinders. Combust. Flame, 32:271276, 1978.
May 15, 2012
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PhD Effects on Burning Behavior and Spread 49
49
50. Matchstick Spread & Burning
Pyrolysis Spread Burnout Time
xp ~ t1.6 to t1.7
x p ~ t 3/2
S 0
xp ~ t
xp tb
(cm)
S
t (s) x (cm)
u ~ gx ~ Re ~ Nu Analytical Predictions
c ln(rf / rs )ri 2
• Predictions suggest the spread
s p, g
tb .
S 4k g ln(1 B)
process 24, 2012
July is dominated by convection 50 s d[c p,s (Ts
yf T ) Hp]
Gollner, M.J., Xie, Y., Lee, M., Nakamura, Y., and Rangwala,
S 0 tb
2k g (T f Ts )
A.S., 2012, In Press, Comb. Sci. Tech.
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50
51. Discrete Fuel Spread Applications
Upward spread through cable trays/ wire arrays
July 24, 2012 51
Tranisition to crown fire behavior (especially important for controlled burns)
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51
52. Conclusions
• Even non-charring fuels can modify the boundary layer
- Corrugated cardboard delaminates (not in current models)
• The heat flux within the B.L. is crucial to understanding
both the flame-spread rate and steady burning
• Discontinuous fuels can achieve spread rates faster than
continuous fuel beds
- Important for transition in wildfires & spread in cable trays
• Flame-spread rates were found to be greatest in near-
vertical orientations while burning rates are maximized in
near-horizontal orientations.
July 24, 2012 52
- Worst-case scenario important for small-scale flammability tests
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52
53. Acknowledgements
• Jonathan Perricone, Garner Palenske and all my colleagues at
Schirmer Engineering for introducing me to this field
• UCSD Graduate Students: Xinyan Huang, Ulrich Niemann and
Ryan Ghemlich for their contributions to laboratory
experiments
• UCSD Undergraduate Students: Jeanette Cobian, Mario Zuniga
and Alexander Marcacci for their contributions to laboratory
experiments
• Worcester Polytechnic Institute Students and staff: Simon Xie,
Minkyu Lee, Randy Harris, Kris Overholt and Todd Hetrick
July 24, 2012 by:
Supported
53
Society of Fire Protection Engineers
Educational and Scientific Foundation
May 15, 2012
May 15, 2012
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53
54. Acknowledgements
• John de Ris, Jose Torero, Adam Cowlard and Yuji
Nakamura for valuable discussions
• The faculty and staff of the UCSD MAE dept.
• Outstanding advisors: Professors Forman A. Williams
and Ali S. Rangwala
• The support of all my family and friends
July 24, 2012 by:
Supported
54
Society of Fire Protection Engineers
Educational and Scientific Foundation
May 15, 2012
May 15, 2012
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54
Fire is still dangerous. In 2010: 1,331,500 fire department calls 3,120 civilian deaths 17,720 civilian injuries 72 firefighter deathsLawyers can make any building legal, only engineers can make it safe. -Vincent Brannigan
My personal motivation began at Schirmer Engineering with industrial fires – Jonathan Perricone who is here today. Met in job fair, was curious, got me hooked on fire research
Coordinates and fuel. 2. theta – angle of orientation to gravity3. Ignition – flame and thermal boundary layer (Tp reached)4. Pyrolysis/flame length. Standoff distance, spread velocity, BL thickness5. Heat flux – to the pyrolsyis region. From flame to virgin fuel. Highlight thermal BL – studiedHighlight heat flux from flame to surface – being studiedInfluence of angle from horizontal – being studied.
Xp is where material reaches temperature, Tp
what happens when the fuel is inclined (and thus the buoyancy is modified)
What if we incline the fuel? Can modify the heat fluxes with gravity.
Coordinates and fuel. 2. theta – angle of orientation to gravity3. Ignition – flame and thermal boundary layer (Tp reached)4. Pyrolysis/flame length. Standoff distance, spread velocity, BL thickness5. Heat flux – to the pyrolsyis region. From flame to virgin fuel. Highlight thermal BL – studiedHighlight heat flux from flame to surface – being studiedInfluence of angle from horizontal – being studied.
Mass-loss rates per unit area. Steady rates here are averages, measured 800-1000s after uniform ignition of the entire sample. For spreading tests, measured mass-loss rates and pyrolyzing surface area increases with time, so result is given once the entire face is ignited, when xp reaches top. Steady rates are significantly higher than spreading rates because of deeper penetration of thermal wave into material at later times. Principal observation – both sets of data exhibit same dependence of MLR on angle, with rates continuously increasing from ceiling to vertical to pool configurations. This results is in contrast to data from Ohtani et al., obtained with the same fuel. They used appreciably smaller samples and agree qualitatively with liquid wick experiments of Blackshear and Kanury, which are what one would expect for convection-controlled burning, because the component of gravity parallel to the fuel surface is maximum in the vertical configuration. Also, since convection-controlled rates would increase with decreasing boundary-layer thicknesses, the observed higher average mass-loss rates per unit area for the smaller samples are expected for this mechanism; in fact, data in that paper point toward a decrease in the rate per unit area with increasing size. It thus appears in the present experiments, at least between vertical and pool configurations, the controlling mechanism is different from that of the smaller samples. Similar to de Ris and Orloff, they suggested that randiant transfer is important in the present experiments (their scale, 0.65m with sidewalls, ours, 10 cm)Could suggest greater propensity for radiant emissions from PMMA than from typical gaseous fuels.
Radiative heat flux varies from 10 to 70 percentQp = qrr + m delta HpQrr = sigma Tp^4 = 6.1 kw/m2Reasons for radiant flux increase with angle: - flux mainly from soot emissions, intensity increase with increased soot volumes and concentrations, and soot made by finite-rate processes in fuelrich zones, so longer fuel-rich residence times lead to more soot and greater emissions. Residence times are minimum with flames, largely blue, on underside and maximum rising above, in pool-burning configuration. In addition, view angle is greatest with pool-burning configuration. Thinner flames at negative angles, this is expected.
Power-law fits appear as straight lines (log-log)-60d to 0d, n=-230d, n=-545d, n=-660d, n=-7Large angles, radiation controlled and view factor between flame and fuel is decreased with increasing angle. Also contribution of convective cooling ahead of fuel surface, instead of convective heating, (go back to diagram)These decrease Vp with increasing theta, explaining our first flame-spread figure for positive angles. The same qualitative differences are expected for very wide samples, since necking and enahnced edge regression cause quantitative not qualititative differences. Fig. 1 is not likely to be different for infinite width. This difference may arise from the mean flow becoming more two-dimensional with increasing distance along the non-pyrolyzing surface; the outflow to the side affects the burning rate but has not yet influenced the heat flux ahead significantly at these angles. The reason for the slight increase of convective heat flux with decreasing angle near vertical is unclear but may be associated with the normal component of gravity pressing the flame closer to the fuel surface, a possibility that deserves further study.
The peak flame-spread rate occurs near -30°The peak mass-loss rate per unit area occurs near +90°In the present experiments, at least between vertical and pool configurations, the controlling mechanism is different from that of the smaller samples1de Ris and Orloff2 suggest radiant transfer is important in their experiments (though larger scales)Could suggest a greater propensity for radiant emissions from PMMA than from typical gaseous fuels.
UL 94 – upward and horizontal spread.
Extending work on boundary layers – what happens when the fuel is discontinuous?
Experimental design approached conditions encountered in practice.