bluuebunny/crossref_metadata_2025_split huggingface dataset:
Waveform modeling of the November 1987 Superstition Hills earthquakes
Authors: Bent Allison L. , Helmberger Donald V. , Stead Richard J. , Ho-Liu Phyllis 
Published: July 2021

AbstractLong-period body-wave data recorded at teleseismic distances and strong-motion data at Pasadena for the Superstition Hills earthquakes of 24 November 1987 are modeled to obtain the source parameters. We will refer to the event that occurred at 0153 UT as EQ1 and the event at 1316 UT as EQ2. At all distances the first earthquake appears to be a simple left-lateral strike-slip event on a fault striking NE. It is a relatively deep event with a source depth of 10 km. It has a teleseismic moment of 2.7 ×1025 dyne cm. The second and more complex event was modeled in two ways: by using EQ1 as the Green's function and by using a more traditional forward modeling technique to create synthetic seismograms. The first method indicated that EQ2 was a double event with both subevents similar, but not identical to EQ1 and separated by about 7.5 sec. From the synthetic seismogram study we obtained a strike of 305° for the first subevent and 320° for the second. Both have dips of 80° and rakes of 175°. The first subevent has a moment of 3.6 ×1025 which is half that of the second. We obtain depths of at least 6 km. The teleseismic data indicate a preferred subevent separation of 30 km with the second almost due south of the first, but the error bounds are substantial. This would suggest that the subevents occurred on conjugate faults. The strong-motion data at PAS, however, imply a much smaller source separation, with the sources probably produced by asperities.
Slip distribution of the 19 September 1985 Michoacan, Mexico, earthquake: Near-source and teleseismic constraints
Authors: Mendoza Carlos , Hartzell Stephen H. 
Published: July 2021

Abstract
We simultaneously invert the strong-motion velocity records and the long- and intermediate-period teleseismic P waveforms of the 19 September 1985 Michoacan, Mexico, earthquake to recover the distribution of slip on the fault using a point-by-point constrained and stabilized, least-squares inversion method. A fault plane with strike fixed at 300° and dip fixed at 14° is placed in the region of the earthquake hypocenter and divided into 120 subfaults. Rupture is assumed to propagate at a velocity of 2.6 km/sec away from the hypocenter. Synthetic near-source ground motions and teleseismic P waveforms for pure strike-slip and dipslip dislocations are calculated for each subfault. The observed data are then inverted to obtain the amount of strike-slip and dip-slip displacement required of each subfault. We also invert the data sets using a time-window procedure where the subfaults are allowed to slip up to three times. This approach relaxes the constraint of fixed subfault rupture time imposed by a constant rupture velocity.
Inversion of the strong-motion data alone yields a slip model similar to the solution previously obtained using only teleseismic waveforms. This result supports the use of teleseismic waveform data for the derivation of fault dislocation models in the absence of strong-motion recordings. Our simultaneous inversion of both data sets suggests that rupture during the Michoacan earthquake was controlled largely by the failure of three major asperities located along the length and down the dip of a 150-km segment of the Cocos-North America plate boundary. The solution contains three major source regions including an 80 km by 55 km source near the hypocenter with a peak slip of 6.5 meters. Two additional sources are present on the southeast portion of the fault about 70 km away from the hypocenter. One of these sources, with a peak slip of 5 meters, covers a 45 km by 60 km area and extends downdip from a depth of about 10 km to 24 km. The third source region is somewhat smaller (30 km by 60 km area, 3.1-meters peak slip) and extends further downdip at depths between 27 km and 39 km. Aftershock activity following the earthquake was associated mainly with the two shallow sources. These two sources are separated by the aftershock zone of the 1981 Playa Azul earthquake.
The case for a shallow-crustal anomalous zone (magma body?) near the south end of Hilton Creek fault, California, including new evidence from an interpretation of pre-Sarrivals
Authors: Peppin William A. , Honjas William , Delaplain Thomas W. , Vetter Ute R. 
Published: July 2021

AbstractSeven independent lines of evidence can be cited for the existence of a shallow-crustal anomalous zone at a site near the south end of Hilton Creek fault, near Mammoth Lakes, California. They are: (1) the presence of a persistent seismic gap since detailed observations began in 1979; (2) S-wave shadowing for travel paths crossing the site; (3) a low-velocity anomaly associated with the south end of Hilton Creek fault discovered by seismic tomography; (4) the observation of two non-double-couple mechanisms for large earthquakes a few km east and west of the site; (5) a concentration of pre-S-arrivals indicative of a possible reflection in the vicinity of this site; (6) a geometric symmetry of source-receiver paths showing pre-S arrivals about this site; and (7) [new evidence presented herein] travel-time fits of strong pre-S arrivals recorded at epicenter of the 1978 Wheeler Crest event (ML 5.7).
Teleseismic and strong-motion source spectra from two earthquakes in eastern Taiwan
Authors: Hwang Lorraine J. , Kanamori Hiroo 
Published: July 2021

AbstractThe 20 May and 14 November 1986 Hualien earthquakes occurred in a seismically active region of Taiwan. Locally determined focal mechanisms and aftershock patterns from the Taiwan Telemetered Seismographic Network indicate that both earthquakes occurred on steeply dipping reverse faults that trend NNE. This agrees with teleseismic first-motion data for the May event but not for the November event. This discrepancy is due to a moderate foreshock before the November event. Surface-wave analysis gives a solution for the November event of: dip 57°, rake 100°, and strike 43°, which is similar to the locally reported focal mechanism. The seismic moment of the November event is M0 = 1.7 × 1027 dynecm and the magnitudes determined from WWSSN data are m^b = 6.4, Ms = 7.3. Teleseismic source spectra show that the two events also have similar spectral signatures above 0.15 Hz. Reference acceleration spectra are computed from the average teleseismic source spectra and compared to the averaged acceleration spectra computed from strong-motion stations for both events. Correlations between the spectral amplitudes of the strong-motion spectra obtained from the main portion of the SMART 1 array and the teleseismically estimated reference spectra are poor above 0.2 Hz. Data from the hard-rock site situated outside of the basin indicates that amplification of the ground motion between 0.17-1.7 Hz is due to the alluvial valley where the SMART 1 array is located. The amplitude of the observed spectrum is five times the reference spectrum at the hard-rock site. This is consistent with similar observations from the 1985 Michoacan and 1983 Akita-Oki earthquakes. The analysis of these and more teleseismic and strong-motion records will lead to a better understanding of the relationship between their spectra.
High-frequency seismic observations and models of chemical explosions: Implications for the discrimination of ripple-fired mining blasts
Authors: Smith Albert T. 
Published: July 2021

AbstractDiscrimination of large chemical explosions (e.g., mining blasts) from possible clandestine nuclear tests (e.g., decoupled explosions) is a significant issue for seismic verification. Unless discrimination is possible, the numerous mining blasts within the USSR would give ample opportunity for concealing a clandestine test. Evernden et al. (1986) advocate high frequencies as a means to detect these clandestine tests; however, mining blasts must still give a unique signature for their discrimination. Specific conditions are also necessary for high-frequency verification: low attenuation and quiet seismic stations are among the most important. In this study we address these problems under conditions representing a best case scenerio.During the summer of 1985, Lawrence Livermore National Laboratory (LLNL) deployed a regional array and high frequency seismic station near RSON (Red Lake, Ontario, Canada) to study regional seismic signals at a low-noise site with excellent propagation characteristics, the continental shield. One objective was to evaluate the performance of regional seismic arrays and high-frequency stations in this geological environment. Using high-frequency data from mining blasts within the Mesabi Iron Range in northern Minnesota (distance of 380 km), we also observed the high-frequency Pn phase of ripple-fired blasts, modeled their source properties, and evaluated a possible discriminant for chemical explosions.This study suggests the existence of a distinctive signature for large chemical explosions: strong, high-frequency spectral peaks in the P spectra introduced by delay shooting or ripple firing. Its application depends, however, on a frequency band extending to at least 35 Hz at regional distances, reasonably uniform delay times in the blast pattern, predictably quiet seismic sites, and minimal path attenuation for high frequencies. At 380 km, we observe good propagation to 30 Hz; at 50 Hz the evidence suggests severe attenuation or scattering which is consistent with a total Q between 1500 and 2500. Attenuation estimates assuming a simple source behavior (e.g., f−2 or f−3) at high frequencies for mining explosions would give incorrect values of Q unless corrected for the blast pattern. These attenuations will limit the value of high frequencies for the detection of small decoupled explosions at regional distances.
Strain and frequency-dependent attenuation estimates in salt based on SALMON and STERLING near-field recordings
Authors: Gupta I. N. , McLaughlin K. L. 
Published: July 2021

Abstract
The amplitude and spectra of teleseismic and regional seismic P waves depend on the material properties in the source region. The effects of strain and frequency-dependent attenuation are therefore important for understanding the source characteristics of coupled versus decoupled explosions. Near-field velocity and acceleration data from the SALMON and STERLING explosions in salt were analyzed for strain and frequency-dependent attenuation. Attenuation, parameterized as 1/Q, was estimated for various source-receiver distance ranges and frequency bandwidths using two methods: mean spectral ratio slope and average amplitude spectral ratio. Results from SALMON indicate that (1) in the frequency range of 1 to 25 Hz, Q is about 5 to 10; (2) Q increases with source-receiver distance, suggesting lower Q for larger strain levels; and (3) Q in the frequency range of 25 to 50 Hz is substantially higher than in the frequency range of 1 to 25 Hz, or Q increases with frequency. Analysis of data from STERLING indicates that Q is frequency independent and about one order of magnitude larger than for SALMON. It appears therefore that the near-source attenuation was strain and frequency dependent and hence nonlinear for SALMON out to a range of at least 600 m.
Transient-wave solution for Lamb's problem at the free surface
Authors: Schiel Klaus , Protázio João S. 
Published: July 2021

Abstract
An exact analytic solution of Lamb's problem is presented with no approximation or restriction for material parameters or source observer geometries. The transient-wave field for a directional point force normal to the surface of an elastic half-space is given in terms of its constituent components: the body waves, the surface wave, and the near field. In contrast to other known solutions, ours enables us to characterize these wave phenomena separately.
Some outstanding features should be mentioned: the singularities appearing in the Green's function solution of the problem are integrable. The transient-wave solution presented is well-suited for numerical computation.
Визначення ефективності перевезень різними транспортними засобами
Authors: Крашенінін О.С. , Шапатіна О.О. 
Published: July 2021

У статті розглянуто питання визначення ефективності перевезень різними транспортними засобами, які розглядаються як системи довготривалої дії. Відповідно до цього зазначено необхідність у рамках взаємодії різних транспортних засобів у процесі надання транспортних послуг комплексно враховувати спосіб виконання завдання та етапи його виконання.
Запропоновано як критерій ефективності перевезень використовувати критерій суми значень множини ймовірностей на показник ефективності.
Формалізовано процес визначення ефективності перевезень шляхом комбінування способів перевезень на кожному етапі виконання транспортних задач.
Моделювання оптимальної дислокації сервісних підприємств залізничного транспорту
Authors: Крашенінін О.С. , Одєгов М.М. , Лагєрєва О.В. , Задесенец В.І. 
Published: July 2021

Традиційна планово-попереджувальна система ТО, ПР тягового рухомого складу (ТРС) у сучасних умовах потребує значних змін. Це пов’язано з необхідністю перебудови системи управління ТО, ПР ТРС в умовах поступового переходу на утримання ТРС за технічним станом і можливості виконання ТО та ПР не тільки в депо приписки ТРС.
Відповідно до цього в статті розглянуто питання щодо моделювання і пошуку оптимальної дислокації центрів з організації аудиту і надання сервісних послуг на утримання ТРС.
Показано, що пошук оптимальної дислокації сервісних центрів доцільно проводити за допомогою положень динамічного програмування.
На основі прогнозної потужності сервісних центрів і необхідних витрат на їх організацію наведено процедуру реалізації моделювання оптимальної дислокації сервісних центрів з обслуговування і ремонту ТРС локомотивних депо.
Secondary wastewater treatment processes optimization
Authors: Sanginova Olga , Tolstopalova Nataliia , Bondarenko Sergii , Yankauskaite Valentyna 
Published: July 2021

Introduction. The level of water pollution in Ukraine continues to grow, despite the strengthening of requirements for the treated water, so the existing approaches to the water treatment processes control need to be revised and improved.
Materials and methods. Mathematical Programming methods for formalization and solving the optimization problem are used. Computer simulation research using the program developed by the authors are applied to verify the compliance of the obtained results with the normative values and data of normal operation.
Results and discussion. The optimization of processes control was performed on the example of a typical process of secondary wastewater treatment, which is used for wastewater treatment in Kyiv and nearby settlements. The secondary treatment unit consists of an aeration tank, into which air is forcibly supplied and evenly distributed, and a secondary settling tank with recycling. The problem of optimization of biological wastewater treatment control process is formalized: minimization of pollutant concentration in treated water is chosen as the main aim of optimization, air flow to aeration tank is chosen as control parameter, quadratic deviation of current concentration values from normative ones is chosen for target function. To solve the optimization task, a software module in JavaScript was developed using a client-server architecture that works in real time and allows to obtain such values of oxygen consumption in the aeration tank, which provide a minimum deviation of the concentration of pollutants from the normative values. The simulations showed that the calculated control values provide a reduction in the concentration of pollutants to the normative values within 6-10 hours, which corresponds to the data of normal operation, and the difference between the calculated and actual data does not exceed 5%.
Conclusions. The obtained results allow to find a set of technological influences to ensure optimal control according to the selected criterion, and are also the basis for calculating the control system. The results of calculations can be used for short-term - up to 8 hours - forecasting of water quality indicators.
The influence of water filtration rate on the efficiency of its oxidization on iron-containing redoxite
Authors: Gomelya Mykola , Holiaka Andrii 
Published: July 2021

Experimet to determine the effectiveness of iron-containing redoxites on the efficiency of water deoxidation. In the course of the study, the dependence of the efficiency of water deoxidation on the filtration rate was determined.
The filtration rate was varied in the range from 5 to 25 mph. The residual oxygen content and the dissolved iron content in the water were determined. It was shown that with increasing filtration rate within these limits, the residual oxygen concentration increases from 0.1-0.2 mg/dm3 to 0.9-1.0 mg/dm3. The residual oxygen content depends not only on the filtration rate but also on the reaction of the medium. An increase in the residual oxygen concentration with increasing pH of the medium from 6.7 to 10.0.
Residual iron content depends little on both the filtration rate and the reaction medium and in all cases did not exceed 0.2 mg / dm3. In this work, the dissolution of iron in general was determined by preliminary preparation for the work of iron-containing redoxite.
When used in the installation scheme, in addition to the column with iron-containing redoxite, also columns with cation exchange resin KU-2-8 in Na-form, almost complete removal of iron ions from the water and natriation softening of tap water was noted. In the case of sodium-cationized water, the extraction of iron from water will be observed for a long time, given the low concentration of iron ions in the water and the high capacity of the cation exchange resin in iron ions. In addition, sorbed iron (II) ions on the cation exchange resin are oxidized by oxygen residues to iron (III). The latter, at elevated pH, are hydrolyzed, which is the reason for the restoration of capacity and cation exchange resin by divalent iron cations.
In the case when after the column with iron-containing redoxite used anion exchange resin AB-17-8 in sulfite form, complete extraction of oxygen from water was achieved.
Given that the oxygen concentration in water with the use of iron-containing composite decreased by 10-40 times, the load on the anion exchange redox will decrease proportionally, which means that the duration of the anion exchange redox filter cycle will increase in the same proportion.
The use of iron in the second stage of the anion exchange resin in the SO32- form remained unchanged, but complete oxygen extraction was achieved. The option is quite promising for implementation.
DETERMINATION OF CORROSION INFLUENCE ON FUEL METAL, OBTAINED FROM SECONDARY POLYMER RAW MATERIALS
Authors: Сhevchenko K. , Grigorov A. , Sinkevich I. 
Published: July 2021

The article proposes to determine the corrosion effect on fuel metals under dynamic conditions, when washing the prepared copper plate of a certain size, a significant amount of fuel at a certain speed and temperature of the study. This approach will significantly reduce the duration of the study (up to 100 minutes) and is closer to the real conditions of contact of the fuel with a metal surface, in comparison with the standardized method, which is widely used today.
Using the proposed laboratory setup, the study was subjected to fuel (200–360 °C), which was obtained by thermal destruction of secondary polymer raw materials, in particular polypropylene. The obtained results showed that the investigated fuel, despite the temperature, the amount of circulating fuel and its water content, does not have a corrosive effect on the copper plate, which can be explained by the absence of corrosive substances in the fuel: water-soluble mineral acids and alkalis, active sulfur compounds and organic acids. However, it should be kept in mind that in polyolefin raw materials, in the form of contamination, there may be products made of other materials, such as rubber and polyvinyl chloride. This can happen when the sorting technology is violated or during the preliminary preparation of raw materials and, in turn, will contribute to the increase in sulfur-containing and chlorine-containing compounds in the fuel, which are characterized by high corrosion activity and should be necessarily removed from the fuel.
Note that the fuel obtained from secondary polymer raw materials, in the absence of sulfur-containing and chlorine-containing compounds, is quite promising for the creation on its basis of modern synthetic fuels, analogues of classic petroleum products.
THEORETICAL AND EXPERIMENTAL STUDIES OF LOW-TEMPERATURE DEHULLING PROCESS OF HIGH-OIL SUNFLOWER UNDER A CENTRIFUGAL FIELD
Authors: Perevalov L. , Golodnjak V. , Demidov I. , Timchenko V. , Piven E. , Molchenko S. 
Published: July 2021

Appearance of high-oily sunflower seeds with oil content 52–54 % in the 60’s of the last century, led to revolutionary changes in raw material base of the fat-and-oil industry, but caused difficulties in the process of its storage and processing due to the morphological structure features and biochemical composition of fruit coat. Overcoming of the main technological disadvantages for high-oily sunflower seeds during dehulling was achieved due to development of an innovative dehulling technology for seeds in frozen state to sub-zero temperatures, which was developed at the technology of fats and fermentation products department of NTU “KhPI”. This paper presents results of experimental study of sunflower variety Ukrainian F1 high-oily seeds dehulling (dehulling coefficient and kernel content coefficient) depending on the temperature change (0–-196°C) and centrifugal dehullerꞌs rotor rotation speed. It has been shown that rational dehulling conditions for dry seeds, which allow to reach maximum dehulling depth (K0 = 0,99) under conditions of minimum outputs of chaff and oilseed dust, are cooling temperature in the range of -30–-50°C and dehullerꞌs rotation speed 26,7 s-1. Based on the literature data and research results, it has been shown that one of the main reasons of dry seeds dehulling coefficient increasing, during the transition from plus to minus temperatures, is a change in basic physicochemical properties of cellulose fibers (the basis of fruit coats biochemical composition) with a solid adsorption surface towards increasing of its strength. According to a special experiment data in relation to change in aggregate state of sunflower oil in temperature range from +20ºС to -196ºС, it was shown that cellulose fibers with adsorbed oil are practically the only component of fruit coat, which increases its plasticity with decreasing temperature. It is noted that fruit coat plasticity increases most significantly in temperature range -30 – -50°C, when oil obtain a plasticine-like consistency. This is exactly what temperature range where minimum yield of chaff and oilseed dust is observed, i.e. the highest dehulling quality is achieved. Obtained scientific results of this study make a significant contribution to the theory and practice of oil seeds dehulling, which have structural and compositional features of the fruit coat.