Scale Modeling Studies on Flame Stretching and Swirling in a Room With Natural Vents

2011 ◽  
Author(s):  
W. K. Chow ◽  
S. S. Han
Keyword(s):  
Side Wall ◽  
Fire Regimes ◽  
Pool Fire ◽  
Flame Height ◽  
Pool Fires ◽  
Scale Modeling ◽  
Modeling Studies ◽  
Long Time ◽  
Set Up ◽  
Room Model

Flame stretching and swirling in a room fire with natural vents will be studied with scale models in this paper. Experiments were carried out in two models of same size 18 cm by 15 cm by 15 cm with or without a movable wall. A total of 16 tests were carried out with different ceiling vent sizes and ventilation arrangement. Different propanol pool fires of diameters 0.11 m to 0.2 m were set up. Volume of propanol varied from 30 ml to 500 ml to give different burning durations. Two pool fires of same volume of fuel and diameter were used in each test, one put in the model and the other burnt outside. The flame lengths of the two fires inside and outside the room model were measured and compared. Two fire regimes under limited ventilation were observed in this scale modeling studies. Firstly, the pool fire inside the model burnt for a longer time with a taller flame when there is no ventilation provided to the model. At the later stage of the fire, the flame height inside the model stretched by over 20% taller than that for the pool fire outside the model. This fire scenario of having tall flame for a long time is very hazardous and should be considered in designing natural vents. Secondly, providing ventilation at the side wall of the model might induce swirling motion inside. Air will be supplied into the model to burn the pool fire faster with short duration. The flame swirled up to a tall height fast but not stretching up slowly as in the case with limited ventilation. The additional air intake flow can be taken as air pumping action.

Flame Stretching in a Room Model With Natural Vent

2009 ◽  
Author(s):  
W. K. Chow ◽  
S. S. Han ◽  
Y. Gao ◽  
H. Dong ◽  
Y. Huo ◽  
...  
Keyword(s):  
Short Note ◽  
Flame Length ◽  
Pool Fire ◽  
Scale Model ◽  
Ceiling Vent ◽  
Set Up ◽  
Room Model ◽  
Real Scale ◽  
Pool Sizes

Flame stretching in a room with a ceiling vent will be discussed in this short note. A real-scale model was constructed with a gasoline pool fire placed inside. Another pool fire of the same size and amount of fuel was burnt outside the model. Different pool sizes of diameters 0.07 m, 0.08 m, 0.11 m, 0.16 m and 0.2 m were set up. Volume of gasoline varied from 30 ml to 500 ml to give different burning durations. The flame lengths of the two fires were measured and compared. It is observed that the flame length of the pool fire inside the room was over 20% higher than that outside at the later stage of the fire.

scholarly journals Acceptance of a Symptom-Based Approach for COVID-19 rtRT-PCR Testing to Conserve Resources in a Lower Middle-Income Setting

2021 ◽  
Vol 12 ◽  
pp. 215013272098771
Author(s):  
S. M. Rashed Ul Islam ◽  
Tahmina Akther ◽  
Md. Abdullah Omar Nasif ◽  
Sharmin Sultana ◽  
Saif Ullah Munshi
Keyword(s):  
Primary Method ◽  
Chain Reaction ◽  
Middle Income ◽  
Clinical Recovery ◽  
Clinical Presentations ◽  
Long Time ◽  
Nasopharyngeal Secretion ◽  
Polymerase Chain ◽  
Set Up

SARS-CoV-2 initially emerged in Wuhan, China in late 2019. It has since been recognized as a pandemic and has led to great social and economic disruption globally. The Reverse Transcriptase Real-Time Polymerase Chain Reaction (rtRT-PCR) has become the primary method for COVID-19 testing worldwide. The method requires a specialized laboratory set up. Long-term persistence of SARS-CoV-2 RNA in nasopharyngeal secretion after full clinical recovery of the patient is regularly observed nowadays. This forces the patients to spend a longer period in isolation and test repeatedly to obtain evidence of viral clearance. Repeated COVID-19 testing in asymptomatic or mildly symptomatic cases often leads to extra workload for laboratories that are already struggling with a high specimen turnover. Here, we present 5 purposively selected cases with different patterns of clinical presentations in which nasopharyngeal shedding of SARS-CoV-2 RNA was observed in patients for a long time. From these case studies, we emphasized the adoption of a symptom-based approach for discontinuing transmission-based precautions over a test-based strategy to reduce the time spent by asymptomatic and mildly symptomatic COVID-19 patients in isolation. A symptom-based approach will also help reduce laboratory burden for COVID-19 testing as well as conserve valuable resources and supplies utilized for rtRT-PCR testing in an emerging lower-middle-income setting. Most importantly, it will also make room for critically ill COVID-19 patients to visit or avail COVID-19 testing at their convenience.

An Experimental Study of the Interaction of Multiple Liquid Pool Fires

1995 ◽  
Vol 117 (1) ◽  
pp. 37-42 ◽  
Author(s):  
J. R. Vincent ◽  
S. R. Gollahalli
Keyword(s):  
Carbon Dioxide ◽  
Large Fraction ◽  
Liquid Pool ◽  
Flame Height ◽  
Design Parameters ◽  
Pool Fires ◽  
Pool Surface ◽  
Flammable Liquids ◽  
Liquid Pools ◽  
Ignition And Combustion

The risk of accidental spills and possible fires is high in the storage and handling of large quantities of flammable liquids. Such liquid pool fires are generally buoyancy-driven and emit a large fraction of their heat release in the form of radiation. Ignition and combustion characteristics of liquid pools depend on the design parameters such as diameter, spacing, and shape of the pools. This laboratory scale study was conducted to determine the effects of these parameters on the characteristics of multiple liquid pool fires. The measurements reported include pool surface regression rate, flame height, temperature, and concentrations of carbon dioxide, soot, and oxygen.

Risk Factors for Typhoid Fever Occurrence and Recurrence in Gombe Metropolis, Gombe State, Nigeria

2021 ◽  
Vol 23 (11) ◽  
pp. 381-401
Author(s):  
Umar Abdullahi Tawfiq ◽  
◽  
Shohaimi Shamarina ◽  
Syafinaz Amin Nordin ◽  
Mohd Noor Hisham Mohd Nadzir ◽  
...  
Keyword(s):  
Risk Factors ◽  
Epidemiological Data ◽  
Simple Random Sampling ◽  
Chi Square ◽  
Long Time ◽  
Chi Square Test ◽  
The Government ◽  
Set Up ◽  
Associated Risk Factors ◽  
At Home

Typhoid is a life-threatening disease that has remained endemic in parts of Africa and Asia where its burden is elevated by the inefficiency of control efforts which have been hampered by lack of epidemiological data, among others. In Nigeria, such data is absent in most of the States like Gombe where the disease has been rife for a long time, hence, to bridge that knowledge gap, this study was set up to determine the host-associated risk factors for typhoid occurrence and recurrence in Gombe. A questionnaire that was designed and validated for this location was used to obtain data from 663 respondents using simple random sampling and analyzed using the Chi-square test for association and binomial logistic regression to obtain risk factors for typhoid occurrence and recurrence, respectively. The study revealed that occurrences were statistically significantly associated with the variables for vaccination (χ2 = 39.729, p < 0.01), having houseboy/girl (χ2 = 16.909, p < 0.01), typhoid patient at home (χ2 = 13.393, p < 0.01), hand washing before handling food (χ2 = 22.856, p < 0.01), consuming iced/frozen items (χ2 = 16.805, p < 0.01), boiling drinking water (χ2 = 49.633, p < 0.01), and eating commercially available foods/drinks (χ2 = 27.864, p < 0.01), while recurrences were statistically significantly predicted by „not sure of been vaccinated‟ (OR = 2.962, CI = 1.290 to 6.802, p < 0.01), „not having another typhoid patient at home‟ (OR = 1.799, CI = 0.998 to 3.244, p < 0.01), and „drinking unboiled water sometimes‟ (OR = 2.130, CI = 1.023 to 4.434, p < 0.01). It is believed that these findings will guide efforts by the Government for health interventions against typhoid in the study area, thus improving the quality of life for the population.

scholarly journals Highland Hill tribe language - an extinct language system needed to be saved

2020 ◽  
Vol 9 (2) ◽  
pp. 3-7
Author(s):  
Tang Minh Chau
Keyword(s):  
Root Culture ◽  
Language System ◽  
Hill Tribe ◽  
Long Time ◽  
Hill Tribes ◽  
Set Up ◽  
Culture And Language

Highland is a typical area in Vietnam with a great deal of unique things for people to study and discover. Among them are culture and language, the two reciprocal elements to create communities called Hill tribes. Original Hill tribes came to the Highland long time ago and set up their life based on their root culture until now. When studying about Hill tribes, we realize that their culture is very interesting and worth tracing. Therefore, how to conserve Hill tribes’ culture is what we need to take into consideration as soon as possible.

Application and Impact of Social Network in Modern Society

2019 ◽  
pp. 30-49 ◽  
Author(s):  
Mamata Rath
Keyword(s):  
Social Network ◽  
Social Systems ◽  
Personal Data ◽  
Modern Society ◽  
Work Culture ◽  
Security Measures ◽  
Home Office ◽  
Emerging Trends ◽  
Long Time ◽  
Set Up

Social network and its corresponding website permits a client to make a profile, set up an authorized account to create a digital representation of themselves, to select other members of the site as contacts, make connections with them, communicate and engage with these users in different social activities, etc. So, social network includes details of persons, group details, their friends list, contact list, business, affiliations, personal data, personal preferences, and historical information. In this age of smart communication and technology, most of the time people are connected with mobile smart telephones in their work culture, home, office, or any other related places. As they are constantly associated with social systems for long time, they get new posts, messages, and current refreshed news readily available in a flash. This is the constructive part of social networking that individuals consistently remain refreshed with most recent news and innovation. This chapter presents an overview of social network design, various issues, and emerging trends that are evolved simultaneously with modern age. It also presents a detail study on application and impact of social network in modern society as well as exhibits an exhaustive review of security measures in social sites.

Statistical-Mathematical Methods Used in Analysis of Trade in Industrial Products

2019 ◽  
Vol 34 ◽  
pp. 315-325
Author(s):  
Tomiță Constantin Vasile ◽  
Luminița Popescu ◽  
Cora Ionela Dăniasă ◽  
Anica Iancu ◽  
Virgil Popescu
Keyword(s):  
Dairy Products ◽  
Economic Importance ◽  
Mathematical Methods ◽  
Close Link ◽  
Human Needs ◽  
Commodity Production ◽  
The People ◽  
Long Time ◽  
Set Up ◽  
The Moment

Dairy products are of great socio-economic importance in Romania today. These products have both nutritional and economic importance. The market is the economic category of commodity production in which it expresses the totality of the sale-purchase acts viewed in an organic unit with the relations it generates and in connection with the space in which it takes place. The market originated a long time ago, being related to the moment when, in order to satisfy their existential needs, "discovered" and increasingly "conscious", the people exchanged between them, respectively collectivities, the surpluses held by each individual - individually or collectively. The exchange, set up as a means of realizing its own interests, has seen various forms and has evolved continuously, being still the foundation of all the economies of the world. The market has grown based on the amplification and diversification of human needs. The satisfaction of these needs is given by the close link between producers and consumers.

scholarly journals Impact of Planter Closing Wheels on Corn Emergence in No-Till Systems

2020 ◽  
Vol 36 (5) ◽  
pp. 727-732
Author(s):  
Jessica L Drewry ◽  
Brian D. Luck ◽  
Francisco J. Arriaga
Keyword(s):  
Cover Crops ◽  
Management Practices ◽  
Side Wall ◽  
List Type ◽  
No Till ◽  
Energy Inputs ◽  
Soil Temperatures ◽  
Plant Emergence ◽  
Rate Of Emergence ◽  
Set Up

HighlightsAftermarket closing wheels increased corn emergence by 2% over standard rubber wheels.Yield was not significant by closing wheel type.Abstract. Producers are increasingly adopting cover crops and no-till planting for a variety of reasons including improving soil fertility and reducing energy inputs. However, adopting these practices may require changes in equipment and management strategy; therefore, research is needed to develop best practices for producers to reduce the risk and encourage adoption. The use of aftermarket closing wheels has been cited as a method to improve emergence under no-till conditions as preparing an ideal seedbed can be more difficult under these conditions due to limited seed-soil contact and side wall compaction. The effect of three aftermarket and the standard rubber closing wheels on emergence and yield under no-till planting of corn into heavy crop residue or cover crops was measured at three Wisconsin locations using a randomized complete block experimental design. Soil temperature and moisture was also monitored during the growing season. Corn plant emergence was measured at least three times to estimate the rate of emergence as a function of growing degree units using air and soil temperatures. The final emergence of corn planted with an aftermarket wheel was found to be significantly higher than the standard rubber closing wheel (p=0.069, a=0.1) across all locations. Yield was not found to be significant by wheel type most likely due to differences in field history and in season management practices. Keywords: Closing wheel, Cover crop, Emergence, No-till, Planter set-up.

scholarly journals Effects of pool size and spacing on burning rate and flame height of two square heptane pool fires

2019 ◽  
Vol 369 ◽  
pp. 116-124 ◽  
Author(s):  
Huaxian Wan ◽  
Zihe Gao ◽  
Jie Ji ◽  
Yongming Zhang ◽  
Kaiyuan Li ◽  
...  
Keyword(s):  
Burning Rate ◽  
Pool Size ◽  
Flame Height ◽  
Pool Fires

Some Experimental Results on Internal Fire Whirls in a Vertical Shaft

2013 ◽  
Author(s):  
Y. Gao ◽  
G. W. Zou ◽  
S. S. Li ◽  
W. K. Chow
Keyword(s):  
Full Scale ◽  
Pool Fire ◽  
Experimental Results ◽  
Vertical Shaft ◽  
Remote Site ◽  
Scale Modeling ◽  
Key Factor ◽  
Fire Whirl ◽  
Real Scale

Earlier studies on burning a pool fire in a vertical shaft model indicated that appropriate sidewall ventilation provision is a key factor for the onset of an internal fire whirl. Experiments on burning a pool fire inside a real-scale shaft model of 9 m tall were performed to further investigate the swirling motion. The full-scale modeling burning tests were carried out at a remote site in China. Four different ventilation openings were arranged. Results of onsetting of internal fire whirls for the four tests will be reported.

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