scholarly journals Investigation Techniques of Arson Fire in Low-Temperature Warehouses Using ED-XRF

2021 ◽  
Vol 35 (6) ◽  
pp. 85-93
Author(s):  
Si-Kuk Kim ◽  
Byeong-Kil Chae ◽  
Yong-Taek Han
Keyword(s):  
Low Temperature ◽  
Fire Suppression ◽  
Galvanized Steel ◽  
Combustion Characteristic ◽  
Flammable Liquid ◽  
Combustion Heat ◽  
Light Oil ◽  
Combustion Experiment ◽  
The Difference ◽  
Start Of Combustion

Investigation techniques for fire prevention in low-temperature warehouses were studied using energy dispersive X-ray fluorescence (ED-XRF). In the first experiment, a sample (galvanized steel sheet plus urethane foam plus sandwich panel) was burned with 500 mL of a flammable liquid (gasoline, thinner, kerosene, and light oil)/ Then, the component change of the sample was measured. In the combustion experiment, there was a difference in the heat of combustion depending on the type of flammable liquid; however, as a result of measuring the component change of the sample with ED-XRF after combustion, the largest component change was measured in the combustion experiment with gasoline. The change was in the order of thinner, kerosene, and diesel. Using ED-XRF, it was possible to distinguish the flammable liquid used in the experiment by measuring the component change of the sample resulting from the difference in the combustion heat of the flammable liquid. A second experiment was conducted under the same conditions as the first experiment, assuming a fire brigade fire suppression condition, and the combustion time of the flammable liquid was limited to 600 s. A combustion characteristic of flammable liquids is that the temperature and heat flux reach the maximum value within 300 s after the start of combustion regardless of the type of liquid. Because the change of composition was confirmed in the order of light oil, it was possible to distinguish the flammable liquid used at the fire site using the ED-XRF measurement result.

scholarly journals 2. On the Polarizability of Heat from different Sources

1845 ◽  
Vol 1 ◽  
pp. 334-334
Author(s):  
Forbes
Keyword(s):  
Low Temperature ◽  
The Difference ◽  
Different Sources

The author of this paper states in it his belief, that the curious fact formerly announced to the Society of the greater permeability of mica, laminated by heat, to heat of low temperature, contrary to the usual character of the same substance (a property which he has since extended (see Proceedings, Jan. 1840) to changes of mechanical conditions of surface), may very probably explain, as M. Melloni anticipates, the difference in point of fact long contested between them as to the equal or unequal polarizability of heat from different sources.

scholarly journals Comprehensive Assimilation of Fire Suppression Modeling and Simulation of Radiant Fire by Water and Its Synergistic Effects with Carbon Dioxide

Energies ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 5850
Author(s):  
Hassan Raza Shah ◽  
Kun Wang ◽  
Xu Qing Lang ◽  
Jing Wu Wang ◽  
Jing Jun Wang ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Synergistic Effects ◽  
Fire Suppression ◽  
Water Mist ◽  
Pool Fire ◽  
Water Suppression ◽  
Water Droplets ◽  
Film Forming ◽  
The Difference ◽  
Suppression Effects

Recently, water has been employed as a supportive agent for the preparation of multiple suppressing agents including aqueous film forming foams (AFFF), which is combined with different kinds of gases for its various applications. In this study, the water mist is chosen for the gas-suppressing agent such as carbon dioxide. Our work investigated the suppression effects of water droplets on the n-heptane pool fire, and its mixture with carbon dioxide, respectively. The size and frequency of droplets with their effect on temperature and suppression was compared to observe the difference in the suppression. Initially, it was found that the droplets having a larger droplet size were found to be more efficient as compared to the smaller droplets with respect to the heat release rate, temperature, and radiation. Afterwards, a mixture of water droplets and carbon dioxide was simultaneously discharged to compare the difference between these two suppressing agents. It was found that the synergistic effect of the mixture has higher advantages over the use of only water suppression. It helps reduce the hot gases that surround the pool fire and allows the water mist to travel efficiently towards the fuel. Both suppression mechanisms were set to similar initial parameters that lead to different outcomes.

Development of one-axis controlled bearingless motor and its application to a centrifugal pump for extremely low temperature

2020 ◽  
Vol 64 (1-4) ◽  
pp. 1287-1294
Author(s):  
Hirohisa Kato ◽  
Mochimitsu Komori ◽  
Ken-ichi Asami ◽  
Nobuo Sakai
Keyword(s):  
Low Temperature ◽  
Centrifugal Pump ◽  
Liquid Nitrogen ◽  
Flow Rate ◽  
Maximum Flow ◽  
Magnetic Bearing ◽  
Lubricating Oil ◽  
Bearingless Motor ◽  
The Difference ◽  
Conventional Study

In this paper, a centrifugal pump for for extremely low temperature was fabricated and evaluated by experiments in liquid nitrogen. The pump is using a bearingless motor and permanent magnet bearings to levitate and rotate the rotor without lubricating oil. The difference from the conventional study is that a one-axis controlled bearingless motor is used to reduce the magnetic bearing cost and that the bearings are installed in the liquid to eliminate a shaft-seal. Stable levitation and rotation of the rotor were confirmed in the rotation and pump experiments in liquid nitrogen. In pump experiment, the flow rate of liquid nitrogen was measured at 1 cm in a pumping height. The maximum flow rate was 1.3 L/min when the rotation speed is 1,800 rpm.

scholarly journals Low-temperature dynamics in amorphous polymers and low-molecular-weight glasses—what is the difference?

2011 ◽  
Vol 13 (5) ◽  
pp. 1843-1848 ◽  
Author(s):  
Ivan Yu. Eremchev ◽  
Yury G. Vainer ◽  
Andrei V. Naumov ◽  
Lothar Kador
Keyword(s):  
Molecular Weight ◽  
Low Temperature ◽  
Amorphous Polymers ◽  
Low Molecular Weight ◽  
Temperature Dynamics ◽  
The Difference

scholarly journals Reduction of titanium oxide in the presence of nickel by nonequilibrium hydrogen gas

2009 ◽  
Vol 24 (7) ◽  
pp. 2391-2399 ◽  
Author(s):  
Hidehiro Sekimoto ◽  
Tetsuya Uda ◽  
Yoshitaro Nose ◽  
Shigeo Sato ◽  
Hiroaki Kakiuchi ◽  
...  
Keyword(s):  
Low Temperature ◽  
Relaxation Process ◽  
Reduction Potential ◽  
Hydrogen Plasma ◽  
Equilibrium Phase ◽  
Hydrogen Gas ◽  
X Ray Diffraction ◽  
Energy Process ◽  
X Ray ◽  
The Difference

We investigated the reduction of TiO2 in the presence of Ni by nonequilibrium hydrogen gas, including low-temperature hydrogen plasma at 800 °C and supercooled monatomic hydrogen at 1000 °C. TiO2 was reduced to Ti2O3, which is not in equilibrium phase, by low-temperature hydrogen plasma. The results of x-ray diffraction and energy dispersive x-ray analysis in experiments at 1000 °C indicate that the thermodynamical reduction potential of supercooled monatomic hydrogen is almost the same as atmospheric hydrogen gas. However, the wide Ti3O5 layer formed only in the case of the reduction at 1000 °C by supercooled monatomic hydrogen. With these experimental facts, we speculate that the reduction mechanism by nonequilibrium hydrogen consists of two steps; the releasing energy process and the relaxation process. We can explain the difference of reduction products by nonequilibrium hydrogen gas on the assumption of the rate of the relaxation process between 800 and 1000 °C.

The economic benefit of localised, short-term, wildfire-potential information

2015 ◽  
Vol 24 (7) ◽  
pp. 974 ◽  
Author(s):  
Laine Christman ◽  
Kimberly Rollins
Keyword(s):  
Fire Suppression ◽  
Economic Value ◽  
Information Service ◽  
Risk Scenarios ◽  
The Us ◽  
Wildfire Suppression ◽  
Information Products ◽  
The Difference ◽  
Wildland Management ◽  
Us West

Wildfire-potential information products are designed to support decisions for prefire staging of movable wildfire suppression resources across geographic locations. We quantify the economic value of these information products by defining their value as the difference between two cases of expected fire-suppression expenditures: one in which daily information about spatial variation in wildfire-potential is used to move fire suppression resources throughout the season, and the other case in which daily information is not used and fire-suppression resources are staged in their home locations all season. We demonstrate the method by constructing a hypothetical wildland management unit calibrated to represent a region typical in the US West. The method uses estimated suppression costs and probabilities of significant fire, as provided by an information service, to estimate expected suppression costs. We analyse differences in expected suppression costs for a range of risk scenarios. Economic savings occur for the majority of risk scenarios. This approach can be used to evaluate investments in wildfire-potential information services, and for assessing the value of investing in new resources.

scholarly journals Influence of the Inner and Outer Secondary Air Ratios on the Combustion Characteristic and Flame Shape of a Swirl Burner with a Prechamber

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Pengzhong Liu ◽  
Fang Niu ◽  
Xuewen Wang ◽  
Fei Guo ◽  
Wei Luo ◽  
...  
Keyword(s):  
High Speed ◽  
Combustion Efficiency ◽  
Flame Length ◽  
Combustion Characteristic ◽  
Swirl Burner ◽  
Free Zone ◽  
Combustion Experiment ◽  
Flame Shape ◽  
Secondary Air ◽  
Low Nitrogen

The swirl burner with a prechamber was used in a 14 MW pulverized-coal combustion experiment to investigate the influence of inner and secondary air ratios (ISA/OSA) on the combustion characteristic and flame shape in this work. The temperatures and species concentrations in the prechamber were measured via the flue gas analyzer and thermocouples. The flame shape beyond the prechamber outlet was captured by using a high-speed camera. The results showed that the combustion efficiency was increased and low nitrogen combustion was achieved by adopting the swirl burner with a prechamber. The high temperature corrosion and slagging phenomenon did not occur in the prechamber. The influence of ISA/OSA on temperature and species concentration profiles at different areas in the prechamber was different. The flame shape size exhibited an inflection point with increasing ISA/OSA. Considering, comprehensively, the temperature peak, near wall temperature, oxygen-free zone, CO concentration, flame length, flame diameter, and divergence angle, the case of ISA/OSA =1 : 2 had great processing on combustion efficiency and NOx emission. Thus, ISA/OSA = 1 : 2 was selected as the optimized case under experiment conditions.

CRITICAL SURFACE EXPONENTS IN 2-D 10-STATE POTTS MODEL

1992 ◽  
Vol 03 (05) ◽  
pp. 1125-1136
Author(s):  
LEO KÄRKKÄINEN ◽  
KARI RUMMUKAINEN
Keyword(s):  
Low Temperature ◽  
Critical Point ◽  
Critical Exponents ◽  
Critical Surface ◽  
Critical Properties ◽  
Interface Tension ◽  
Potts Models ◽  
Singular Behaviour ◽  
The Difference ◽  
Twisted Boundary Conditions

At low temperature, the Potts models can have interfaces between domains ordered to different directions. We use the difference of periodic and twisted boundary conditions to study planar order-order interfaces. We show that the interface tension, energy and width display critical properties as one approaches the critical point. We measure the critical exponents connected to their power like singular behaviour at the critical point.

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