scholarly journals A Study on a Modified Model for the Hold Time of a Clean Extinguishing Agent

2021 ◽  
Vol 11 (21) ◽  
pp. 10312
Author(s):  
Goonho Kim ◽  
Jee-Hun Jeong ◽  
Hyun-Jeong Bang ◽  
Ho-Jun Lee
Keyword(s):  
Theoretical Model ◽  
Variable Exponent ◽  
Hold Time ◽  
Theoretical Equation ◽  
Integrity Test ◽  
Modified Model ◽  
Time Prediction ◽  
Maximum Improvement ◽  
Leakage Characteristics ◽  
Leakage Exponent

When estimating the theoretical hold time of a Clean Extinguishing Agent (CEA), the hold time is predicted using a leakage exponent and leakage characteristics that are measured through an Enclosure Integrity Test (EIT). In particular, the leakage exponent n is conventionally applied as 0.5, but recently, a variable exponent has been applied through measurement (approximately 0.48 to 0.85). When variable n is applied, the hold time varies greatly depending on the size of n. Therefore, in this study, a modified theoretical model for the hold time of a CEA is proposed to improve the accuracy of the hold time depending on the leakage exponent n. The modified theoretical model applies a different analysis of the inflow and outflow volumetric flow, and the results enable a more accurate hold time prediction. The modified theoretical equation shows an improvement of up to 8.6% for outflow volumetric flow V˙o and a maximum improvement of approximately 10.7% for hold time th.

scholarly journals A Study on the Effect of O2 Diffusion on the Retention Time of Inert Agents

2020 ◽  
Vol 10 (19) ◽  
pp. 6694
Author(s):  
GoonHo Kim ◽  
Ju-Hong Cha ◽  
Jee-Hun Jeong ◽  
Ho-Jun Lee
Keyword(s):  
Theoretical Model ◽  
Retention Time ◽  
Hold Time ◽  
Theoretical Models ◽  
Accurate Model ◽  
Fire Extinguishing ◽  
A Value ◽  
O2 Diffusion ◽  
In Fire ◽  
And Diffusion

Gaseous agents are widely used in fire extinguishing systems (FESs) when water extinguishing agents are unavailable. The extinguishing ability of the FES-gaseous agent is determined by the retention time (hold time) at which its concentration is maintained. In particular, the retention time of the inert agent is determined by the O2 inflow from the outside. However, current theoretical models for inert agents do not provide an accurate model for the diffusion of incoming O2. Specifically, because the theoretical equations do not include O2 diffusion or include too large a value, there is a large difference between the measured and theoretical retention times. Therefore, in this study, accurate O2 diffusion was verified through experimental and numerical analyses using three types of deactivators and reflected in the existing theoretical model. O2 diffusion was analyzed through the interface slope α and diffusion velocity vd. As a result, this proposed method can predict the retention time more accurately than existing theoretical models.

Comparison of the Results Obtained in Simulation of SERB Dampers Using Two Different Hysteresis Models

2018 ◽  
Vol 880 ◽  
pp. 353-358
Author(s):  
Adriana Ionescu ◽  
Mihai Negru ◽  
Cristian Oliviu Burada
Keyword(s):  
Theoretical Model ◽  
Energy Dissipation ◽  
Seismic Behavior ◽  
Seismic Energy ◽  
Theoretical Models ◽  
Modified Model ◽  
The Difference ◽  
Energy Dissipation Devices ◽  
Comparison Of The Results ◽  
Damping Systems

This paper presents the difference between the results obtained with GenEcAm in simulating the seismic behavior of a P + 10E building equipped with SERB dampers modeled with two hysteresis models, namely the classic Bouc-Wen model and a Bouc-Wen modified model Bouc-Wen_Exp, in order to highlight the most appropriate theoretical model for modeling these dampers. The GenEcAm program is created by the author for the dynamic analysis during seism for structures of buildings equipped with different earthquake damping systems, with the possibility to use 9 different theoretical models of hysteresis for simulating the hysterical behavior of seismic energy dissipation devices that fit the antiseismic system of the analysed building.

Deterministic Localization and Analysis of Scan Hold-Time Faults

2008 ◽  
Author(s):  
Jaecheol Hwang ◽  
Daegyu Kim ◽  
Namsik Seo ◽  
Euncheol Lee ◽  
Wooseong Choi ◽  
...  
Keyword(s):  
Hold Time ◽  
Close Correlation ◽  
Failure Behavior ◽  
Analysis Method ◽  
Integrity Test ◽  
Data Dependencies ◽  
Traditional Approaches ◽  
Timing Models ◽  
Require Data

Abstract This paper presents a deterministic diagnosis analysis method for hold-time faults in scan chains. The defects discussed in this paper are primarily seen at low Vdd values, so called Vdd-min defects; Vdd -max defects can also be a problem. Traditional approaches require data collection, the creation of additional patterns, and an iterative trip back to the tester. This is a time consuming process and does not always lead to a closed end solution. This paper also presents a method to detect multiple hold-time faults in the chain using auto generated pattern, real-time on the tester. The approach includes validation of the hold-time fault model, characterization of the failure behavior in terms of Vdd and data dependencies and finally localization to a cone of logic including the data paths and the clock trees. This method of hold-time localization is organized into three steps. First, the chain integrity test is run at the safe voltage. Second, a set of new patterns is created and run at the failing voltage. Finally, the data is shifted out and compared with the simulation result. The data provides the locations of all of the hold-time faults for the selected failing voltage. Combined with silicon voltage probing, the technique allows the analysis to localize the faults and to measure timing slack on sub-nets in the failing circuitry. This allows very close correlation between timing models and silicon performance leading to more robust design/process matching.

Spiral Power Springs. Part 2—Design

1971 ◽  
Vol 93 (2) ◽  
pp. 676-682 ◽  
Author(s):  
C. A. Queener ◽  
G. E. Wood
Keyword(s):  
Theoretical Model ◽  
Shape Factor ◽  
Empirical Equation ◽  
Logarithmic Spiral ◽  
Companion Paper ◽  
Theoretical Equation ◽  
Extended Model ◽  
Practical Application ◽  
Good Accord ◽  
Frictional Hysteresis

The theoretical model developed in a preceding companion paper for predicting the torque-turn behavior of a spiral power spring is extended in an effort to improve the practical applicability. A theoretical equation based on springback theory is developed for computing the shape factor in the logarithmic spiral and an empirical equation for calculating the magnitude of frictional hysteresis is obtained. The extended model is tested with two springs and the experimental and calculated results are in good accord. The computation procedure involved in practical application of the extended model for spring design is discussed.

Correlation Between the Interfacial Nonuniformity and the Specific Contact Resistance of Ohmic Contacts to Gaas

1990 ◽  
Vol 181 ◽  
Author(s):  
T. Q. Tuy ◽  
I. Mojzes ◽  
V. V. Tuyen ◽  
I. Cseh
Keyword(s):  
Theoretical Model ◽  
Contact Resistance ◽  
Ohmic Contacts ◽  
Contact Region ◽  
Specific Contact Resistance ◽  
Simultaneous Presence ◽  
Modified Model ◽  
Specific Contact ◽  
Heavily Doped ◽  
Bulk Semiconductor

ABSTRACTConsidering the effect of the simultaneous presence and interaction of the different phases at the contact, a modification of the model presented by Wu and coworkers (Solid-St. Electron. 29 (1986) 489] for explanation of ohmic contact resistance of n-GaAs was developed. The modified model combines the existence of the mixed phase structure of AuGeNi/n-GaAs contact with assumptions proposed by Wu et al. that the specific contact resistance Rc contains two parts Rcl and Rc2, where Rc1 is the specific contact resistance of the alloyed and underlaying doped contact region, and Rc2, is that of the high-low junction between the heavily doped contact region and the bulk semiconductor. The Rc1 depends strongly on the apparent barrier height and the effective impurity concentration formed by doping from the contact alloys during annealing. In the present paper a new theoretical model for Rc1 is proposed and compared with the experimental results.

scholarly journals Ontferming “beyond” vergeving als weg naar heling en heelheid: Een theoretisch model voor narratief pastoraat

2004 ◽  
Vol 60 (3) ◽  
Author(s):  
Tiny Van der Schaaf
Keyword(s):  
Theoretical Model ◽  
Paul Ricoeur ◽  
Modified Model ◽  
Paul Ricœur ◽  
Pastoral Counselling

Mercy beyond forgiveness as way to healing and wholeness: A theoretical model for narrative pastoral counsellingThe article explores the model of Christie Neuger with regard to pastoral counselling with women who have been sexually violated in an ecclesial context. This model is complemented by the narrative philosophy of Paul Ricoeur. The article focuses on the following questions: What are the conditions for forgiveness? How can the abused woman find forgiveness in her heart? What is the role of the pastor? What happens if the woman cannot forgive? What are the theological implications of forgiveness? How can pastor and counselee together reframe the story of violence? The article argues that Ricoeur’s notions of prefiguration, configuration and refiguration complement Neuger’s theoretical model. This modified model presents a possible way to healing and wholeness.

Information Searching: The Case of Tourism Promoted Through the Internet

2015 ◽  
Vol 16 (1) ◽  
pp. 33-47
Author(s):  
Ratidanai Hoonsawat
Keyword(s):  
International Trade ◽  
Theoretical Model ◽  
Destination Country ◽  
International Tourism ◽  
The Internet ◽  
Model Estimation ◽  
Information Searching ◽  
Modified Model ◽  
Internet Penetration ◽  
Tourism Flows

This paper theoretically modifies the Anderson and Wincoop ( 2003 ) model on international trade to explain international tourism flows. In addition, this modified model can measure the effect of the Internet penetration at origin and destination countries through misinformation. The theoretical model implies that potential tourists use the Internet to gather information on their destination country through its websites. Through gravity model estimation, results show the significance of the Internet in the origin country as well as destination country.

scholarly journals A New Model for Real-Time Prediction of Wellbore Stability Considering Elastic and Strength Anisotropy of Bedding Formation

Energies ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 251
Author(s):  
Liqin Ding ◽  
Zhiqiao Wang ◽  
Jianguo Lv ◽  
Yu Wang ◽  
Baolin Liu
Keyword(s):  
Theoretical Model ◽  
Real Time ◽  
Field Data ◽  
In Situ Stress ◽  
Wellbore Stability ◽  
Real Field ◽  
Strength Anisotropy ◽  
Safety Control ◽  
Time Prediction

Severe wellbore stability issues were reported while drilling in laminated formation with weak planes such as beddings. To accurately determine the safe mud weight according to the changing environment is of primary importance for safety control of drilling. Considering both the elastic and strength anisotropy of bedding formation, a novel theoretical model is established and the stress and failure around wellbores are analyzed. The accuracy and applicability of the theoretical model is verified by in situ field data. For the purpose of fulfilling real-time prediction, the method flowchart of programming is also provided. The results show that the model built can be conveniently used to predict the stress distribution, failure area, and collapse and fracture pressure while drilling, and rather good predictions can be made compared to real field data. In addition, the inhomogeneity of in situ stress and elastic parameters affect the upper limit of the safe mud weight window (SMWW) greater than the lower limit. Negative SMWW may appear with the direction change of the wellbore or weak plane, especially when the azimuths of them change. As to the magnitude of SMWW, the anisotropic effects of Young’s modulus are greater than the Poisson’s ratio. The method established in this paper can greatly help with the precise prediction of wellbore stability as drilling proceeds in bedding formation.

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