scholarly journals Critical slot size for deflagration initiation by hot products discharge into hydrogen–air atmospheres

2017 ◽  
Vol 42 (2) ◽  
pp. 1298-1305 ◽  
Author(s):  
Jaime Carpio ◽  
Immaculada Iglesias ◽  
Marcos Vera ◽  
Antonio L. Sánchez
Keyword(s):  
Slot Size ◽  
Hot Products

2006 Hot Products

2006 ◽  
Vol 31 (6) ◽  
pp. 38-40 ◽  
Author(s):  
Fran Hildwine
Keyword(s):  
Hot Products

Effects of Exit Vent Location on Fire Room Conditions During PPV

2008 ◽  
Author(s):  
Colin M. Beal ◽  
Ofodike A. Ezekoye
Keyword(s):  
Positive Pressure ◽  
Computational Simulations ◽  
Cold Flow ◽  
Flow Simulations ◽  
Advantages And Disadvantages ◽  
Experimental Compartment ◽  
Dynamic Simulator ◽  
Fire Dynamic Simulator ◽  
Hot Products ◽  
Vent Location

Positive Pressure Ventilation (PPV) is a widely used fire fighting tactic in which a fan is used to push hot products of fire out of a burning structure. There is a recent body of research that has been conducted regarding the advantages and disadvantages of PPV. Studies of PPV most commonly use full scale experimental fires and/or computational simulations to evaluate its effectiveness. This paper presents computational simulations that have been conducted using Fire Dynamic Simulator (FDS) version 5 to evaluate the effects of exit vent location on resulting fire room conditions during the application of PPV to a ventilation constrained fire. The simulations use a simple one room structure with an adjacent hallway. We are simulating this geometry because we are in the process of designing and constructing a similar experimental compartment. Cold flow simulations are first conducted to understand how much the presence of the fire heat release affects the flow patterns. Then, two simulations which employ PPV with different exit vent locations are compared. The differences between the two simulations are detailed and a physical explanation for the differences is presented.

scholarly journals Effect of Bracket’s Slot Size on Canine Position and Space Closure Rate (A Typodont Study)

2014 ◽  
Vol 14 (1) ◽  
pp. 60-69
Author(s):  
Khudair Al-Jumaili ◽  
Abdulrahman Ali ◽  
Hydar Shindala
Keyword(s):  
Closure Rate ◽  
Space Closure ◽  
Slot Size

scholarly journals Prediction of Slot Shape and Slot Size for Improving the Performance of Microstrip Antennas Using Knowledge-Based Neural Networks

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Taimoor Khan ◽  
Asok De
Keyword(s):  
Neural Networks ◽  
Artificial Neural Networks ◽  
Prior Knowledge ◽  
Neural Model ◽  
Microstrip Antennas ◽  
Performance Parameters ◽  
Dual Frequency ◽  
Knowledge Based ◽  
Slot Size ◽  
Good Agreement

In the last decade, artificial neural networks have become very popular techniques for computing different performance parameters of microstrip antennas. The proposed work illustrates a knowledge-based neural networks model for predicting the appropriate shape and accurate size of the slot introduced on the radiating patch for achieving desired level of resonance, gain, directivity, antenna efficiency, and radiation efficiency for dual-frequency operation. By incorporating prior knowledge in neural model, the number of required training patterns is drastically reduced. Further, the neural model incorporated with prior knowledge can be used for predicting response in extrapolation region beyond the training patterns region. For validation, a prototype is also fabricated and its performance parameters are measured. A very good agreement is attained between measured, simulated, and predicted results.

scholarly journals Gaseous combustion at high pressures. Part XV.— The formation of nitric oxide in carbonic oxide-oxygen-nitrogen explosions

1933 ◽  
Vol 139 (837) ◽  
pp. 74-83 ◽  
Keyword(s):  
Nitric Oxide ◽  
High Pressures ◽  
Volume Ratio ◽  
Optimum Composition ◽  
Normal Rate ◽  
Secondary Formation ◽  
Spherical Explosion ◽  
Rate Of Cooling ◽  
Hot Products

In previous papers of this series it was shown that the secondary formation of nitric oxide in CO-O 2 -N 2 explosions, when oxygen is present in excess of that required to burn all the carbonic oxide, rapidly increases with the density of the medium, the optimum composition of the medium for the purpose being 2CO + 3O 2 + 2N 2 . The former experiments were carried out, in bombs Nos. 2 and 3, the 7·5 cm. diameter spherical explosion chambers of which were each of 240 c.c. capacity with a surface/volume ratio 0·78, under conditions permitting of no acceleration in the normal rate of cooling down of the hot products from the maximum explosion temperature.

Assessment of Slot Influence in the Fatigue Thermal Life of Coke Drums

2012 ◽  
Author(s):  
Gabriel A. Vivas ◽  
Egler D. Araque ◽  
Alberto D. Pertuz ◽  
Masaaki Oka
Keyword(s):  
Low Cycle Fatigue ◽  
Thermal Response ◽  
Pressure Vessels ◽  
Second Step ◽  
Element Analysis ◽  
Fatigue Lifetime ◽  
Hole Radius ◽  
Slot Size ◽  
Thermal Life ◽  
Mathematical Relations

Delayed coke drums are vertical thin-walled pressure vessels that operate under severe conditions by cyclic heating and quenching operations. The high stresses can lead to premature drum failure in the form of through wall cracking resulted from low cycle fatigue. One of the ways that has been used to reduce the growth of cracks localized near the shell to skirt weld is by the addition of different slots configurations in the skirt. In order to estimate fatigue life, a finite element analysis (FEA) was carried out using a decoupled thermo-mechanical assessment. In the first step, a thermal analysis was done to estimate the variation of temperature throughout the coking cycle. In the second step, this thermal response was combined with the mechanical loads to estimate the total stress and strain. The validity of the models has been demonstrated by several FEA results and by some field measured data. It is proposed a set of mathematical relations that allows predicting the behavior of fatigue lifetime as a function of slot size and hole radius.

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