Seismic analysis of the 7 January 1998 Chemical plant explosion at Kean Canyon, Nevada

1999 ◽  
Vol 89 (4) ◽  
pp. 938-945 ◽  
Author(s):  
Gene A. Ichinose ◽  
Kenneth D. Smith ◽  
John G. Anderson
Keyword(s):  
Seismic Analysis ◽  
Correlation Method ◽  
Chemical Safety ◽  
P Waves ◽  
Arrival Times ◽  
Chemical Company ◽  
Optimal Separation ◽  
The Difference ◽  
Possible Cause

Abstract An accident at the Sierra Chemical Company Kean Canyon plant, 16 km east of Reno, Nevada, resulted in two explosions 3.52 sec apart that devastated the facility. An investigation into a possible cause for the accident required the determination of the chronological order of the explosions. We resolved the high-precision relative locations and chronology of the explosions using a cross-correlation method applied to both seismic and air waves. The difference in relative arrival times of air waves between the explosions indicated that the first explosion occurred at the northern site. We then determined two station centroid separations between explosions, which average about 73 m with uncertainties ranging from ± 17 to 41 m depending on the alignment of station pairs. We estimated a centroid separation of 80 m using P waves with a larger uncertainty of ± 340 m. We performed a grid search for an optimal separation and the azimuth by combining air-wave arrivals from three station pairs. The best solution for the relative location of the second explosion is 73.2 m S35°E from the first explosion. This estimate is well within the uncertainties of the survey by the U.S. Chemical Safety and Hazard Investigation Board (CSB). The CSB reported a separation of approximately 76.2 m S33°E. The spectral amplitudes of P waves are 3 to 4 times higher for the second explosion relative to the first explosion, but the air waves have similar spectral amplitudes. We suggest that this difference is due to the partitioning of energy between the ground and air caused by downward directivity at the southern explosion, and upward directivity at the northern explosion. This is consistent with the absence of a crater for the first explosion and a 1.8-m-deep crater for the second explosion.

scholarly journals DETERMINATION OF EARTHQUAKE FOCUS COORDINATES USING THE CASSINI OVAL METHOD WITH SECOND- AND FOURTH-ORDER HYPERBOLA FIGURES

2020 ◽  
Vol 46 (4) ◽  
pp. 134-142
Author(s):  
B. I. Shakhtarin ◽  
T. G. Aslanov ◽  
U. R. Tetakaev
Keyword(s):  
Comparative Analysis ◽  
Fourth Order ◽  
Relative Position ◽  
Seismic Waves ◽  
Arrival Times ◽  
Earthquake Focus ◽  
Seismic Sensors ◽  
Calculation Results ◽  
The Difference

Objectives. To study the dependencies obtained when determining the coordinates of an earthquake hypocentre using the figures of fourth and second orders.Method. A comparative analysis of determining the coordinates of the earthquake focus using the Cassini oval method, both taking errors in the readings of seismic sensors into account the and ignoring them, is presented.Result. A new method is proposed for determining the coordinates of the earthquake hypocentre, which uses the fourth-order figure, the Cassini oval, in the calculations. A graph is obtained for the distribution of errors in determining the coordinates of the earthquake focus (using the Cassini oval) depending on the relative position of two seismic sensors with different values of their errors in determining the difference in travel times of seismic waves.Conclusion. Since the calculation results are independent of the error sign in determining the difference in the arrival times of seismic waves, the method is suitable for the initial determination of the coordinates of the earthquake hypocentre as well as for comparison with the results of other methods for identifying the error sign. 

Arrival times of P waves and upper mantle structure

1964 ◽  
Vol 54 (2) ◽  
pp. 727-736
Author(s):  
Eysteinn Tryggvason
Keyword(s):  
Standard Error ◽  
Upper Mantle ◽  
P Wave ◽  
P Waves ◽  
Arrival Times ◽  
P Wave Velocity ◽  
Upper Mantle Structure ◽  
The Mean ◽  
The Difference ◽  
Mantle Velocity

ABSTRACT Residuals of arrival times of P waves, as given in the International Seismological Summary for Kiruna, Sweden, Reykjavik, Iceland, and Scoresbysund, Greenland, were studied in order to detect upper mantle anomalies. The Kiruna arrivals were systematically too early, with a mean residual of −1.4 seconds, while the mean Reykjavik residual was +1.3 seconds. The difference in mean residual was 2.7 seconds with a standard error of about 0.5 second. The mean residual at Scoresbysund was −0.4 second. It is assumed that there is a depth D below which the mantle is homogeneous. The difference in mean residuals at the stations is assumed to be caused by different wave velocities at depths less than D in the vicinities of the stations. If it is assumed that the P-wave velocity in the upper mantle is constant down to a depth D below each station, this depth can be computed. This velocity is known from other data to be 8.36 km/sec below Kiruna and 7.4 km./sec. below Reykjavik. If only earthquakes at distances from 20° to 39° were used, D is determined to be 246 ± 36 km. (standard error). Earthquakes at distances 40° to 59° give D = 177 ± 25 km., at distances 60° to 79° give D = 234 ± 14 km., and at distances 80° to 99° give D = 281 ± 20 km. The most probable value of D is thus about 240 km. below the earth's surface, with a standard error of about 40 km. In the vicinity of Scoresbysund the upper mantle velocity is found to be about 8.0 km./sec., using the same assumption.

Multiple Scattering by Two Centers of Force

1973 ◽  
Vol 51 (12) ◽  
pp. 1322-1334
Author(s):  
L. Gauthier ◽  
M. Razavy
Keyword(s):  
Multiple Scattering ◽  
Scattering Amplitude ◽  
Scattering Length ◽  
Solvable Model ◽  
High Energy ◽  
S Wave ◽  
P Waves ◽  
Additional Information ◽  
The Difference

A solvable model for scattering by two centers of force is studied. The force at each center is assumed to be a separable force acting on the S wave only. A force law of this kind enables one to find the scattering amplitude for overlapping as well as nonoverlapping potentials analytically. The resulting scattering amplitudes can be used to compare the range of validity of the Born and other high energy approximations and also to test the accuracy of the result obtained by retaining the leading terms in the multiple scattering series. By examining the relation between the exact scattering amplitude for the two centers and the scattering amplitude of one center, it is shown that in the case of nonoverlapping potentials, the former amplitude can be expressed completely in terms of the latter. Hence no additional information about the nature of force results from the determination of the two-center scattering amplitude. However, for overlapping potentials, one can discriminate among equivalent potentials by finding the scattering amplitude for the two-center-of-force problem. Finally to justify the use of a potential which acts only in one partial wave (l = 0), the following observation has been made. If one calculates the scattering length for two nonoverlapping hard sphere interactions, using S-wave scattering by each center, and then repeats the calculation for the same interactions but considers S and P waves and their interference, the difference between the two results will be quite small.

FRACTIONAL DETERMINATIONS OF URINARY 17-KETOSTEROIDS IN HYPEREMESIS GRAVIDARUM

1962 ◽  
Vol 41 (1) ◽  
pp. 123-128 ◽  
Author(s):  
Pentti A. Järvinen ◽  
Sykkö Pesonen ◽  
Pirkko Väänänen
Keyword(s):  
Hyperemesis Gravidarum ◽  
First Trimester ◽  
Control Group ◽  
Before And After ◽  
Daily Urine ◽  
First Trimester Of Pregnancy ◽  
The Difference

ABSTRACT The fractional determination of 17-ketosteroids in the daily urine was performed in nine cases of hyperemesis gravidarum and in four control cases, in the first trimester of pregnancy both before and after corticotrophin administration. The excretion of total 17-KS is similar in the two groups. Only in the hyperemesis group does the excretion of total 17-KS increase significantly after corticotrophin administration. The fractional determination reveals no difference between the two groups of patients with regard to the values of the fractions U (unidentified 17-KS), A (androsterone) and Rest (11-oxygenated 17-KS). The excretion of dehydroepiandrosterone is significantly higher in the hyperemesis group than in the control group. The excretion of androstanolone seems to be lower in the hyperemesis group than in the control group, but the difference is not statistically significant. The differences in the correlation between dehydroepiandrosterone and androstanolone in the two groups is significant. The high excretion of dehydroepiandrosterone and low excretion of androstanolone in cases of hyperemesis gravidarum is a sign of adrenal dysfunction.

THE SUBJECT FIELD OF INSTITUTIONAL EDUCATION: THE SENSE AND PROSPECTS OF DEVELOPMENT IN UKRAINE

2020 ◽  
pp. 25-38
Author(s):  
Irina Mordous
Keyword(s):  
Decisive Role ◽  
Subject Field ◽  
National Education ◽  
Progressive Development ◽  
Separate Area ◽  
Economic Transformations ◽  
The Difference ◽  
The Individual ◽  
Political Economic

The development of modern civilization attests to its decisive role in the progressive development of institutions. They identified the difference between Western civilization and the rest of the world. Confirmation of the institutional advantages of the West was its early industrialization. The genesis and formation of institutionalism in its ideological and conceptualmethodological orientation occurs as a process alternative to neoclassic in the context of world heterodoxia, which quickly spread in social science. Highlighting institutional education as a separate area of sociocultural activity is determined by the factor of differentiation of institutional theory as a whole. A feature of institutional education is its orientation toward the individual and his/her transformation into a personality. The content of institutional education is revealed through the analysis of the institution, which includes a set of established customs, traditions, ways of thinking, behavioral stereotypes of individuals and social groups. The dynamics of socio-political, economic transformations in Ukraine requires a review of the foundations of national education and determination of the prospects for its development in the 21st century in the context of institutionalism.

scholarly journals Possibility of Human Gender Recognition Using Raman Spectra of Teeth

Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 3983
Author(s):  
Ozren Gamulin ◽  
Marko Škrabić ◽  
Kristina Serec ◽  
Matej Par ◽  
Marija Baković ◽  
...  
Keyword(s):  
Raman Spectra ◽  
Principal Component ◽  
Support Vector ◽  
Gender Recognition ◽  
Proof Of Concept ◽  
Male And Female ◽  
Tooth Type ◽  
Tooth Apex ◽  
The Difference

Gender determination of the human remains can be very challenging, especially in the case of incomplete ones. Herein, we report a proof-of-concept experiment where the possibility of gender recognition using Raman spectroscopy of teeth is investigated. Raman spectra were recorded from male and female molars and premolars on two distinct sites, tooth apex and anatomical neck. Recorded spectra were sorted into suitable datasets and initially analyzed with principal component analysis, which showed a distinction between spectra of male and female teeth. Then, reduced datasets with scores of the first 20 principal components were formed and two classification algorithms, support vector machine and artificial neural networks, were applied to form classification models for gender recognition. The obtained results showed that gender recognition with Raman spectra of teeth is possible but strongly depends both on the tooth type and spectrum recording site. The difference in classification accuracy between different tooth types and recording sites are discussed in terms of the molecular structure difference caused by the influence of masticatory loading or gender-dependent life events.

scholarly journals Influence of Erythrocytes on Direct Potentiometric Determination of Sodium and Potassium

1983 ◽  
Vol 20 (2) ◽  
pp. 116-120 ◽  
Author(s):  
P Bijster ◽  
H L Vader ◽  
C L J Vink
Keyword(s):  
Whole Blood ◽  
Potassium Concentration ◽  
Reference Electrode ◽  
Sodium Concentration ◽  
General Phenomenon ◽  
Liquid Junction ◽  
Direct Potentiometry ◽  
The Difference ◽  
Sodium And Potassium

We have shown that the sodium concentration in whole blood measured by direct potentiometry is higher than in plasma. The ‘erythrocyte-effect’, already described by Siggaard Andersen, is most pronounced for instruments equipped with a reference electrode with an open static liquid junction and is thus a general phenomenon. Instruments with a modified liquid junction show less interference. The same phenomenon appears for the determination of the potassium concentration, although the difference between whole blood and plasma, when measured with instruments equipped with a modified liquid junction, can be neglected in practice.

Method for the simultaneous quantification of n-hexane metabolites: application to n-hexane metabolism determination

1996 ◽  
Vol 15 (6) ◽  
pp. 497-503 ◽  
Author(s):  
T. Soriano ◽  
M. Menéndez ◽  
P. Sanz ◽  
M. Repetto
Keyword(s):  
Similar Pattern ◽  
Analytical Procedure ◽  
Daily Basis ◽  
Practical Application ◽  
Simultaneous Quantification ◽  
Exposed Workers ◽  
Before And After ◽  
Time Requirements ◽  
The Difference

1 The described analytical procedure permits the simultaneous determination of the main n-hexane meta bolites in urine. 2-Hexanone, 2-hexanol, 2, 5-hexanediol and 2, 5-hexanedione, were chosen to dose the rats used in this study. All urine samples were collected and analysed on a daily basis, before and after acidic hydrolysis (pH 0.1) by GC/MS. 2-Hexanone, 2, 5-dimethylfurane, γ-valerolac tone and 2, 5-hexanedione were determined before hydro lysis ; 2-hexanol and 2, 5-hexanediol, after hydrolysis; and 5-hydroxy-2-hexanone and 4, 5-dihydroxy-2-hexanone were calculated by the difference between γ-valerolactone and 2, 5-hexanedione with and without hydrolysis, respectively. 2 A metabolic scheme was proposed reflecting the biotransformations undergone by the four compounds assayed. We consider 2, 5-dimethylfurane as a 'true metabolite' because the quantities detected were always greater before hydrolysis. 3 It has been reported that human and rat n-hexane metabolism follow a similar pattern. Therefore, as a practical application and without increasing either sample or time requirements, the simultaneous quantifi cation of the different metabolites and their excretion profile could provide better information about the metabolic situation of exposed workers than the determi nation of 2, 5-hexanedione alone. According to our experimental results, 4, 5-dihydroxy-2-hexanone itself would be a good toxicity indicator.

Determination of Resistance to Abrasive Wear. VIII. Influence of Softeners in Tests with the Akron-Croydon and Du Pont Machines

1949 ◽  
Vol 22 (1) ◽  
pp. 259-262
Author(s):  
J. F. Morley
Keyword(s):  
Unit Area ◽  
Published Data ◽  
The Road ◽  
Abrasive Surface ◽  
Abrasive Power ◽  
The Difference ◽  
On The Road ◽  
The Right ◽  
Abrasion Testing

Abstract These experiments indicate that softeners can influence abrasion resistance, as measured by laboratory machines, in some manner other than by altering the stress-strain properties of the rubber. One possible explanation is that the softener acts as a lubricant to the abrasive surface. Since this surface, in laboratory abrasion-testing machines, is relatively small, and comes repeatedly into contact with the rubber under test, it seems possible that it may become coated with a thin layer of softener that reduces its abrasive power. It would be interesting in this connection to try an abrasive machine in which a long continuous strip of abrasive material was used, no part of it being used more than once, so as to eliminate or minimize this lubricating effect. The fact that the effect of the softener is more pronounced on the du Pont than on the Akron-Croydon machine lends support to the lubrication hypothesis, because on the former machine the rate of wear per unit area of abrasive is much greater. Thus in the present tests the volume of rubber abraded per hr. per sq. cm. of abrasive surface ranges from 0.03 to 0.11 cc. on the du Pont machine and from 0.0035 to 0.0045 cc. on the Akron-Croydon machine. On the other hand, if the softener acts as a lubricant, it would be expected to reduce considerably the friction between the abrasive and the rubber and hence the energy used in dragging the rubber over the abrasive surface. The energy figures given in the right-hand columns of Tables 1 and 3, however, show that there is relatively little variation between the different rubbers. As a test of the lubrication hypothesis, it would be of interest to vary the conditions of test so that approximately the same amount of rubber per unit area of abrasive is abraded in a given time on both machines; this should show whether the phenomena observed under the present test conditions are due solely to the difference in rate of wear or to an inherent difference in the type of wear on the two machines. This could most conveniently be done by considerably reducing the load on the du Pont machine. In the original work on this machine the load was standardized at 8 pounds, but no figures are quoted to show how abrasion loss varies with the load. As an addition to the present investigation, it is proposed to examine the effect of this variation with special reference to rubbers containing various amounts and types of softener. Published data on the influence of softeners on the road wear of tire rubbers do not indicate anything like such large effects as are shown by the du Pont machine. This throws some doubt on the value of this machine for testing tire tread rubbers, a conclusion which is confirmed by information obtained from other workers.

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