scholarly journals Description of Muzzle Blast by Modified Ideal Scaling Models

1998 ◽  
Vol 5 (1) ◽  
pp. 1-12 ◽  
Author(s):  
Kevin S. Fansler
Keyword(s):  
Energy Release ◽  
Location Parameter ◽  
Forward Direction ◽  
Data Correlation ◽  
Muzzle Blast ◽  
Data Scatter ◽  
Scaling Models ◽  
Two Parameters ◽  
Release Model ◽  
Instantaneous Energy

Gun blast data from a large variety of weapons are scaled and presented for both the instantaneous energy release and the constant energy deposition rate models. For both ideal explosion models, similar amounts of data scatter occur for the peak overpressure but the instantaneous energy release model correlated the impulse data significantly better, particularly for the region in front of the gun. Two parameters that characterize gun blast are used in conjunction with the ideal scaling models to improve the data correlation. The gun-emptying parameter works particularly well with the instantaneous energy release model to improve data correlation. In particular, the impulse, especially in the forward direction of the gun, is correlated significantly better using the instantaneous energy release model coupled with the use of the gun-emptying parameter. The use of the Mach disc location parameter improves the correlation only marginally. A predictive model is obtained from the modified instantaneous energy release correlation.

scholarly journals Modeling extreme minimum air temperature series under climate change conditions

2011 ◽  
Vol 41 (11) ◽  
pp. 1877-1883 ◽  
Author(s):  
Gabriel Constantino Blain
Keyword(s):  
Air Temperature ◽  
Extreme Value Distribution ◽  
Location Parameter ◽  
Kendall Test ◽  
Temperature Series ◽  
Rate Of Change ◽  
Stationary Model ◽  
Climate Conditions ◽  
Two Parameters ◽  
Minimum Air Temperature

Considering the presence of non-stationary components, such as trends, in the extreme minimum air temperature series available from three locations of the State of São Paulo-Brazil, the aim of this research was to describe the probabilistic structure of this variable by using a non-stationary model (based on the general extreme value distribution; GEV model) in which the parameters are estimated as a function of time covariate. The Mann-Kendall test has proven the presence of significant increasing trends in all analyzed series. Furthermore, according to the Pettitt (changing-point) test, 1991 is the initial year of these trends (in the three locations). The applied selection criteria indicated that a GEV model in which the location parameter is estimated as a function of time is recommended to describe the probability structure of the variable under evaluation. The others two parameters of this model remained time-independent. According to this non-stationary model, the detected trends in the climate conditions of these locations have shown the same rate of change (0.04°C per year).

Research on work efficiency and energy release model of Al/PTFE mixture under electric ignition

2021 ◽  
Vol 127 ◽  
pp. 105517
Author(s):  
Enling Tang ◽  
Chang Liu ◽  
Yafei Han ◽  
Chuang Chen ◽  
Mengzhou Chang ◽  
...  
Keyword(s):  
Energy Release ◽  
Work Efficiency ◽  
Release Model

scholarly journals A Quadriparametric Model to Describe the Diversity of Waves Applied to Hormonal Data

2018 ◽  
Vol 57 (03) ◽  
pp. 101-110
Author(s):  
Thomas Bouchard ◽  
Amna Klich ◽  
Rene Leiva ◽  
Cecilia Pyper ◽  
Christophe Genolini ◽  
...  
Keyword(s):  
Scale Parameter ◽  
Principal Component ◽  
Location Parameter ◽  
Smoothing Splines ◽  
Growth Mixture Models ◽  
Scale Parameters ◽  
Growth Mixture ◽  
Functional Principal Component ◽  
Best Fitting ◽  
Two Parameters

Summary Background: Even in normally cycling women, hormone level shapes may widely vary between cycles and between women. Over decades, finding ways to characterize and compare cycle hormone waves was difficult and most solutions, in particular polynomials or splines, do not correspond to physiologically meaningful parameters. Objective: We present an original concept to characterize most hormone waves with only two parameters. Methods: The modelling attempt considered pregnanediol-3-alpha-glucuronide (PDG) and luteinising hormone (LH) levels in 266 cycles (with ultrasound-identified ovulation day) in 99 normally fertile women aged 18 to 45. The study searched for a convenient wave description process and carried out an extended search for the best fitting density distribution. Results: The highly flexible beta-binomial distribution offered the best fit of most hormone waves and required only two readily available and understandable wave parameters: location and scale. In bell-shaped waves (e.g., PDG curves), early peaks may be fitted with a low location parameter and a low scale parameter; plateau shapes are obtained with higher scale parameters. I-shaped, J-shaped, and U-shaped waves (sometimes the shapes of LH curves) may be fitted with high scale parameter and, respectively, low, high, and medium location parameter. These location and scale parameters will be later correlated with feminine physiological events. Conclusion: Our results demonstrate that, with unimodal waves, complex methods (e.g., functional mixed effects models using smoothing splines, second-order growth mixture models, or functional principal-component- based methods) may be avoided. The use, application, and, especially, result interpretation of four-parameter analyses might be advantageous within the context of feminine physiological events.

A Study on Damage Properties of Explosive Internal-Blast of Concrete

2012 ◽  
Vol 598 ◽  
pp. 420-424
Author(s):  
Qing Tao Wang ◽  
Jue Ding ◽  
Meng Kan Ying ◽  
Bao Liang Zhang
Keyword(s):  
Energy Release ◽  
Numerical Study ◽  
Damage Effect ◽  
Building Structures ◽  
Sph Method ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Detonation Process ◽  
Release Model ◽  
Heavy Damage

Blast can cause serious loss of people live and property，and heavy damage on building structures. So, a numerical study on internal-blast-field characteristics and dynamic response of concrete by aluminized explosive was conducted. Moreover, three energy release models of aluminized explosive with combustion effects were compared and analyzed. The numerical study shows that the ignition and growth model is one three-form equation of reaction rate, which can describe unsteady detonation process of non-ideal explosives well. So, in this paper, the energy release model of aluminized explosive based on the Lee-Tarver rate equation was utilized, and an internal-blast dynamic model of concrete was established. The smoothed particle hydrodynamics (SPH) method was adopted to research the explosion field and damage effects of concrete, and provides an important way to evaluate the damage effect of internal-blast of the concrete.

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