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Articles 1 - 14 of 14
Full-Text Articles in Physical Sciences and Mathematics
Western Science And Eastern Zen To Seek The Origin Of Truth: Philosophical Background Of Scale Modeling, Kozo Saito
Western Science And Eastern Zen To Seek The Origin Of Truth: Philosophical Background Of Scale Modeling, Kozo Saito
Progress in Scale Modeling, an International Journal
This article was written to introduce philosophical background of scale modeling, where Zen philosophy was applied to overcome the limitation of logical thinking and hypotheses-driven deductive science. Three specific reasons are as follows. The first is related to the law approach in scale modeling; it uses the kufu principle, originated in Zen Buddhism, together with the other three scientific methods: experimental, theoretical, and computational. The second reason is because scale modeling seeks relativistic understanding by attempting to realize similarity; the concept is closer to Eastern philosophy rather than absolute understanding cultivated by deductive science. The third is in the educational …
Tricritical Point As A Crossover Between Type-Is And Type-Iis Bifurcations, Prabakaran Rajamanickam, Joel Daou
Tricritical Point As A Crossover Between Type-Is And Type-Iis Bifurcations, Prabakaran Rajamanickam, Joel Daou
Progress in Scale Modeling, an International Journal
A tricritical point as a crossover between (stationary finite-wavelength) type-Is and (stationary longwave) type-IIs bifurcations is identified in the study of diffusive-thermal (Turing) instability of flames propagating in a Hele-Shaw channel in a direction transverse to a shear flow. Three regimes exhibiting different scaling laws are identified in the neighbourhood of the tricritical point. For these three regimes, sixth-order partial differential equations are obtained governing the weakly nonlinear evolution of unstable solutions near the onset of instability. These sixth-order PDES may be regarded as the substitute for the classical fourth-order Kuramoto–Sivashinsky equation which is not applicable near the …
Scale Model Experiments Of Toxic Gas Production From The Combustion Of Polymers When Applied With Different Droplet Sizes Of Water Mist, Nicharee Thinnakornsutubutr, Masayuki Mizuno, Kazunori Kuwana
Scale Model Experiments Of Toxic Gas Production From The Combustion Of Polymers When Applied With Different Droplet Sizes Of Water Mist, Nicharee Thinnakornsutubutr, Masayuki Mizuno, Kazunori Kuwana
Progress in Scale Modeling, an International Journal
This research experimentally investigated the combustion of polymeric materials with water mist application in an enclosure, with an emphasis on the production of toxic gases. Two different diameters, ~100 and ~260 μm, were tested. The experimental conditions were determined based on Froude similarity laws for low drop Reynolds number conditions. Droplets and polymers’ physical and chemical properties influence the burning/extinguishing behavior and toxic-gas evolution. In general, larger droplets can extinguish a fire in a shorter time, and toxic gas concentrations in a test chamber decreased more rapidly. However, the large droplets tended to cause the flame expansion phenomenon for thermoplastics …
A Simplified Model For The Intermediate Structure Of Strong Fire Whirls, Forman A. Williams
A Simplified Model For The Intermediate Structure Of Strong Fire Whirls, Forman A. Williams
Progress in Scale Modeling, an International Journal
A model is described for the overall structure of intense fire whirls, based on a spatially evolving vortex, with circulation enhancement driven by the axial acceleration of low-density gas in the core through the axial pressure gradient. The axial acceleration increases the entrainment rate into the core which, through mass conservation, increases the circulation if the angle between the tangential and radial velocity components remains fixed. The two-zone model employs general balance equations for regions inside and outside a cylinder of fixed radius, each inviscid, the inside region being presumed to have a constant density small compared with the (constant) …
Reduced-Scale Experiments And Numerical Simulations Of Informal Settlement Dwelling Fires, Vigneshwaran Narayanan, Antonio Cicicone, Ayden D. Botha, Richard Shaun Walls
Reduced-Scale Experiments And Numerical Simulations Of Informal Settlement Dwelling Fires, Vigneshwaran Narayanan, Antonio Cicicone, Ayden D. Botha, Richard Shaun Walls
Progress in Scale Modeling, an International Journal
Informal settlement dwellings (ISDs) house approximately one billion people in the developing world and this number is expected to double by the year 2030. Contemporary research on ISD fires has focused on understanding the fire dynamics within individual dwellings (micro-scale) and fire spread in settlements consisting of multiple dwellings (macro-scale). This paper aims to do two primary things: investigate if scaling methods that were derived for compartments with thermally thick boundaries can be applied to ISDs (compartments with thermally thin boundaries), and if they can adequately represent the most important phenomena associated with full-scale ISD fires; and demonstrate Fire Dynamics …
Open-Field Scale-Model Experiments Of Fire Whirls Over L-Shaped Line Fires, Yuto Iga, Kazunori Kuwana, Kozo Sekimoto, Yuji Nakamura
Open-Field Scale-Model Experiments Of Fire Whirls Over L-Shaped Line Fires, Yuto Iga, Kazunori Kuwana, Kozo Sekimoto, Yuji Nakamura
Progress in Scale Modeling, an International Journal
This paper presents the results of open-field scale-model experiments of fire-whirl formation over line fires. L-shaped line fires were burned in crosswinds, and the processes of fire-whirl formation were observed. The flame height was measured using an image-processing technique, while two-dimensional velocity components were measured at two different locations using ultrasonic anemometers. Two tests were selected for comparison: test A, in which intense fire whirls repeatedly formed, and test B, in which no whirls were observed. In test A, the wind flow was bent by the fire plume, creating swirling flows near the burning area, thereby forming fire whirls. On …
Effect Of Reduced Plume Entrainment On The Burning Rate Of Porous Fuel Beds, Sara Mcallister
Effect Of Reduced Plume Entrainment On The Burning Rate Of Porous Fuel Beds, Sara Mcallister
Progress in Scale Modeling, an International Journal
Large outdoor fires often exhibit unexpected fire behavior, particularly compared with much smaller fires. Understanding the difference between large- and small-scale fires is of importance for both fire behavior predictions and safety. Large fires are often characterized by very tall plumes that can extend to the stratosphere. Particularly as the actively burning area increases, plumes in large-scale fires likely entrain relatively little and may act in a similar fashion to a chimney. To explore the possible changes in burning rate due to the chimney effect, experiments were conducted with wood cribs burned with a chimney of variable height. The burning …
Scale Model Test To Estimate Thermal Damage By Fire In Aircraft Cargo, Jian Gao, Tsuneyoshi Matsuoka, Yuji Nakamura
Scale Model Test To Estimate Thermal Damage By Fire In Aircraft Cargo, Jian Gao, Tsuneyoshi Matsuoka, Yuji Nakamura
Progress in Scale Modeling, an International Journal
The Federal Aviation Administration (FAA) requires fire detectors to alarm within one minute of the start of a fire in cargo compartments of airplanes. To determine whether such alarm timing works, investigations of the thermal damage to ceilings and other structures during the early stage of a fire were accomplished to demonstrate compliance with these FAA regulations. The objective was to test the feasibility of predicting convective heat transfer in early stage of a cargo compartment fire by conducting reduced scale (lab scale) experiments. First, the scaling laws was derived and validated. Then, full-scale and half-scale experiments were performed with …
Extinguishment Of Diffusion Flames Formed Over A Porous Plate Burner Using Rubber Balloons Filled With Inert Gases, Hiroyuki Torikai, Shinya Kudo
Extinguishment Of Diffusion Flames Formed Over A Porous Plate Burner Using Rubber Balloons Filled With Inert Gases, Hiroyuki Torikai, Shinya Kudo
Progress in Scale Modeling, an International Journal
We have proposed an inert gas, rubber-balloon extinguishing method which might increase the effectiveness of extinguishing flames and decreasing the amounts of agents needed for fire suppression. Hence, extinguishing experiments have been performed to further clarify possible extinguishing characteristics, mechanisms and scaling effects of this method. Carbon dioxide, nitrogen, argon and helium gases were used as the extinguishing agents. Methane-air and propane-air diffusion flames were formed on two different diameter, round porous plate burner and used as the targets for extinguishment. The extinguishing probabilities were measured, and the extinguishing processes were observed with a high-speed camera. As a result, an …
Effects Of Dimensionless Numbers On Decomposition Of Methane Hydrate, Shoma Shimizu, Genichiro Kushida
Effects Of Dimensionless Numbers On Decomposition Of Methane Hydrate, Shoma Shimizu, Genichiro Kushida
Progress in Scale Modeling, an International Journal
It is necessary to elucidate the decomposition and combustion of methane hydrate for fire safety during transportation and storage to utilize it for commercial practice. The amount of methane evolved during the decomposition of methane hydrates is affected by the conditions such as the initial temperature, initial density and ambient temperature. In the present study, the internal temperature of methane hydrate and the amount of methane evolved during its decomposition were investigated by a dimensionless numerical analysis using a transient one-dimensional conduction model from a symmetrical methane hydrate ball heated by ambient air. The numerically calculated central temperature and the …
A Study On Fire Hazards Of Oil Tanks In Urban Areas With Scale Model Experiments, Ho Yin Ng, Yu Wan, Wan Ki Chow
A Study On Fire Hazards Of Oil Tanks In Urban Areas With Scale Model Experiments, Ho Yin Ng, Yu Wan, Wan Ki Chow
Progress in Scale Modeling, an International Journal
Large fuel tanks are located in an urban area of Tsing Yi in Hong Kong, giving potentially high risks to people living nearby if a fire was to occur. Scale modeling experiments were carried out to investigate the potential of fire hazards. Propanol pool fires with five different scales of oil tanks were studied first. Appropriate tank sizes were then put in a 1/2500 architectural scale model on the Tsing Yi Island to study a fuel tank fire. Results show that the heat and smoke from a fire would affect occupants staying in areas near to the fuel tanks. Fire …
Fingering Behavior Of Flame Spread Over Solid Combustibles, Tsuneyoshi Matsuoka, Kentaro Nakashima, Takuma Kajimoto, Akihiro Yoshimasa, Yuji Nakamura
Fingering Behavior Of Flame Spread Over Solid Combustibles, Tsuneyoshi Matsuoka, Kentaro Nakashima, Takuma Kajimoto, Akihiro Yoshimasa, Yuji Nakamura
Progress in Scale Modeling, an International Journal
In this study, the fingering pattern formation and the following flamelet spreading over three different kinds of thick combustibles, i.e., Poly methacrylate (PMMA), Poly ethylene (PE) and Poly carbonate (PC) were observed and the effective Lewis number correlation was validated. Experiments were performed with a narrow channel apparatus. In addition to the kinds of solid fuel materials, the channel height and the oxidizer velocity were varied as experimental parameters. An image analysis method was developed to quantify the number, diameter and spread rate of the flamelets. Replacing the fuel thickness into the thermal thickness, the effective Lewis number which is …
Data-Driven Tools Guided By First-Principles For Scale Modeling, Sadegh Poozesh
Data-Driven Tools Guided By First-Principles For Scale Modeling, Sadegh Poozesh
Progress in Scale Modeling, an International Journal
For decades, traditional scale-modeling techniques have been relying on first-principles models (FPMs). FPMs have been used to find non-dimensional numbers (PIs) and identify normalized underlying forces and energies behind the phenomenon in focus. The two main challenges with FPM-based PIs extraction are finding the relevant PIs and proper correlations between PIs. The emergence and surge of data-driven modeling (DDM) provide a new opportunity to leverage experimental data in model development across scales/plants. In this paper, first, the two mentioned issues in PIs development will be elaborated to reveal the gap, and second, a new insight into scale modeling and similarity …
The Model Area In Successful Lean Transformation And Scale Modeling, William Cooper, M. Abbot Maginnis, David Parsley, Kozo Saito
The Model Area In Successful Lean Transformation And Scale Modeling, William Cooper, M. Abbot Maginnis, David Parsley, Kozo Saito
Progress in Scale Modeling, an International Journal
The True Lean System Program at the University of Kentucky was created in 1994 to study how the development of the Toyota Production System (TPS) contributes to Toyota’s success. This increased understanding of Toyota’s experience would provide useful guidance to Western companies taking on the challenges of replicating Toyota’s success within their own organizations. The common struggle point shared by the companies who come to us is their inability to establish sustainable TPS-based Lean transformations throughout their organizations. Our work with these companies along with our study of Toyota’s own experience in bringing TPS to its own American operations has …