A scaled charge weight superposition model for rapid vibration estimation

Fragblast ◽  
2006 ◽  
Vol 10 (1-2) ◽  
pp. 9-31 ◽  
Author(s):  
A. T. Spathis
Keyword(s):  
Charge Weight ◽  
Superposition Model ◽  
Vibration Estimation

The use of the spatial characteristics technique with the view of estimating the explosion wave impact on the stuck drilling string zone / Wykorzystanie techniki charakterystyk przestrzennych do określania wpływu fali uderzeniowej na przychwyconą kolumnę przewodów wiertniczych

2012 ◽  
Vol 57 (3) ◽  
pp. 601-618 ◽  
Author(s):  
Vasyl Moisyshyn ◽  
Vasyl Yacyshyn ◽  
Oleg Vytyaz
Keyword(s):  
Drill Pipe ◽  
Charge Weight ◽  
Practical Implementation ◽  
Problem Solution ◽  
Wave Impact ◽  
Spatial Characteristics ◽  
Explosion Wave ◽  
Deformation State ◽  
Drilling String ◽  
Threaded Joints

Abstract Studied here are the results of the asymmetric problem solution of the thick walled circular cylinder elasticity using the spatial characteristics technique. The practical implementation of the solution of the problem is based on the calculation of the stress-caused deformation state of the stuck drilling string zone affected by the explosion wave action upon the inner wall of the pipe. Suggested here is the technique for determining axual σz and circular σθ stress on the drill pipe wall as well as the radial displacements ur of the stuck drill pipe outer surface under the action of the explosion shock wave. The above technique enables to make a sound selection of the cylindrical explosive charge weight in order to avoid the residual strain during the drilling string shaping off and uncoupling the threaded joints or to prevent them from exceeding the admissible level.

EPR, optical and superposition model study of Mn2+doped L+ glutamic acid

2015 ◽  
Vol 113 (23) ◽  
pp. 3891-3899
Author(s):  
Ram Kripal ◽  
Manju Singh
Keyword(s):  
Glutamic Acid ◽  
Superposition Model ◽  
Model Study

Numerical simulation of gas-solid two-phase reaction flow with multiple moving boundaries

2015 ◽  
Vol 25 (2) ◽  
pp. 375-390 ◽  
Author(s):  
Qiao Luo ◽  
Xiaobing Zhang
Keyword(s):  
Numerical Simulation ◽  
Physical Phenomenon ◽  
Great Influence ◽  
Moving Boundaries ◽  
Charge Weight ◽  
Phase Reaction ◽  
Two Phase ◽  
Content Type ◽  
One Dimensional ◽  
Chamber Volume

Purpose – In engineering applications, gas-solid two-phase reaction flow with multi-moving boundaries is a common phenomenon. The launch process of multiple projectiles is a typical example. The flow of adjacent powder chambers is coupled by projectile’s motion. The purpose of this paper is to study this flow by numerical simulation. Design/methodology/approach – A one-dimensional two-phase reaction flow model and MacCormack difference scheme are implemented in a computational code, and the code is used to simulate the launch process of a system of multiple projectiles. For different launching rates and loading conditions, the simulated results of the launch process of three projectiles are obtained and discussed. Findings – At low launching rates, projectiles fired earlier in the series have little effect on the launch processes of projectiles fired later. However, at higher launching rates, the projectiles fired first have a great influence on the launch processes of projectiles fired later. As the launching rate increases, the maximum breech pressure for the later projectiles increases. Although the muzzle velocities increase initially, they reach a maximum at some launching rate, and then decrease rapidly. The muzzle velocities and maximum breech pressures of the three projectiles have an approximate linear relationship with the charge weight, propellant web size and chamber volume. Originality/value – This paper presents a prediction tool to understand the physical phenomenon of the gas-solid two-phase reaction flow with multi-moving boundaries, and can be used as a research tool for future interior ballistics studies of launch system of multiple projectiles.

scholarly journals A seismologically motivated survey of blasting activity in the northern Rhine area

2000 ◽  
Vol 79 (1) ◽  
pp. 73-80 ◽  
Author(s):  
Klaus-G. Hinzen ◽  
Stefan Pietsch
Keyword(s):  
Charge Weight ◽  
Time Interval ◽  
Maximum Charge ◽  
Comprehensive Test Ban Treaty ◽  
Comprehensive Test ◽  
Explosive Charges ◽  
Chemical Explosions ◽  
Working Day ◽  
Test Ban ◽  
Natural Earthquakes

AbstractDiscrimination between quarry blasts and earthquakes has gained importance due to signature of the Comprehensive Test Ban Treaty. In this context, large chemical explosions are significant. In the routine analysis of data from local seismograph networks, discrimination between smaller blasts and micro-earthquakes is not always clear. Many quarries are in operation and blasts far outnumber natural earthquakes in the highly industrialized northern Rhine area.We compiled a list of active quarries in the Northern Rhine Area and mapped their locations. We then created a database from a questionnaire sent out to all quarries on the list. From the 33% of questionnaires that were returned, we discerned some representative values for the main blasting parameters and explosive consumption. In the study area of 72,000 km2, approx. 21,000 blasts are fired per year (80 per working day). Most of the blasts (72%) have total explosive charges between 400 and 4500 kg. Shots with charges above 10 tons are rare (20-30 per year). Some 80% of the blasts are ripple-fired with a nominal firing time interval of 20 ms.Based on empirical amplitude vs. distance curves from vibration control measurements, a relation between maximum charge weight per delay time, L (kg), and a ‘quarry blast’ magnitude, MQB, is derived: MQB = 0.6·log10(L) + 0.131. Using this relation and extrapolating the database from the questionnaire shows that for magnitudes between 1 and 2, blasts occur 200–250 times more frequently than micro-earthquakes in the Northern Rhine area.

A Re-Look Into Modified Scaled Distance Regression for Prediction of Blast-Induced Ground Vibration

2021 ◽  
Vol 12 (1) ◽  
pp. 22-39
Author(s):  
Saha Dauji
Keyword(s):  
Performance Measures ◽  
Ground Vibration ◽  
Blast Waves ◽  
Charge Weight ◽  
Mining Activities ◽  
Weight Estimation ◽  
Industrial Practice ◽  
Scaled Distance ◽  
Conservative Values ◽  
Distance Approach

Underground blasts are conducted for deep excavations, tunneling, or mining activities. Scaled distance regression analysis is performed in industry to estimate peak particle velocity from charge weight and distance. For addressing the uncertainties in estimating safe charge weight for controlled blasting, 95% confidence expression is generally used. For addressing inaccuracies arising from superimposition of blast waves in multi-hole blasting when using attenuation equation developed from single-hole blast data, a modified approach was proposed in literature. This article presents comparisons to establish that industrial practice of scaled distance regression would be as satisfactory as the proposed modified approach, when various performance measures (including parsimony) are considered together. Furthermore, industrial practice of using 95% confidence expression generated from sufficient data (say, 40 numbers) would result in safe charge weight estimation, whereas modified scaled distance approach (mean expression) could still result in few non-conservative values.

Investigation of the Spin Hamiltonian Parameters of Yb3+ in CaWO4 Crystal

2004 ◽  
Vol 59 (12) ◽  
pp. 943-946 ◽  
Author(s):  
Hui-Ning Dong ◽  
Shao-Yi Wu
Keyword(s):  
Hyperfine Structure ◽  
Local Structure ◽  
Reasonable Agreement ◽  
Second Order ◽  
Order Perturbation ◽  
Superposition Model ◽  
Spin Hamiltonian ◽  
Structure Constants ◽  
Hamiltonian Parameters ◽  
G Factors

In this paper, the spin Hamiltonian parameters g factors g∥ and g⊥ of Yb3+ and hyperfine structure constants A∥ and A⊥ of 171Yb3+ and 173Yb3+ in CaWO4 crystal are calculated from the two-order perturbation formulae. In these formulae, the contributions of the covalence effects, the admixture between J =7/2 and J =5/2 states as well as the second-order perturbation are included. The needed crystal parameters are obtained from the superposition model and the local structure of the studied system. The calculated results are in reasonable agreement with the observed values. The results are discussed.

scholarly journals Ground accelerations caused by large quarry blasts

1961 ◽  
Vol 51 (2) ◽  
pp. 191-202
Author(s):  
D. E. Hudson ◽  
J. L. Alford ◽  
W. D. Iwan
Keyword(s):  
Response Spectrum ◽  
Strong Motion ◽  
Complete Response ◽  
Charge Weight ◽  
Total Charge ◽  
Ground Acceleration ◽  
Acceleration Time

Abstract Ground acceleration-time measurements have been made within 2000 ft. of two quarry blasts of total charge weight 185 tons and 673 tons. Ground accelerations were of a character and magnitude similar to those associated with damaging earthquakes. Complete response spectrum curves calculated from the acceleration records are presented. Direct comparisons are made between these results and previous similar measuements and calculations using identical instruments, which have been made of strong-motion earthquakes, H. E. blasts, and the Rainier nuclear blast.

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