bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evaluation of efficiency and environmental safety of leaching metals from ore: ways of development and prospects
Authors: Lyashenko Vasil , Khomenko Oleh , Chekushina Tatiana , Dudar Tamara , Topolnij Fedor 
Published: July 2021

The object of research is traditional mining technologies and technical means in combination with underground block leaching (UBL) of metals from rock ores with their preliminary crushing with explosives in installations mounted in mine workings. One of the most problematic areas is the difficulty of achieving a given crushing quality, as well as the required height of ore storage in the chamber for the subsequent leaching of metals and a loosening factor, taking into account the control of the energy of explosive destruction of rock ores.
The study used:
– data from literary sources and patent documentation in the field of technologies and technical means for UBL of metals from ores in energy disturbed massifs, substantiation of technological parameters of operational blocks;
– laboratory and production experiments;
– physical modeling of metal extraction from ores from the average linear size of a piece of blasted ore.
Analytical studies, comparative analysis of theoretical and practical results using standard and new methods were carried out with the participation of the authors. It was found that the most intensive infiltration leaching occurs when the size class of ore lumps is –100+0 mm. Metals are extracted from fractions –200+100 mm less intensively and for a longer time. To neutralize and flush the spent ore mass, it is recommended to treat it with lime solution and mine water through wells for supplying leaching solutions (irrigation system). The protection of the hydrogeological environment is carried out by silting the bottom of the chamber for collecting productive solutions with clay solution and by constant monitoring of mine water pollution in the zone of UBL influence. On the basis of the positive results obtained from the study and implementation of technologies for UBL of metals from rock ores during the development of block 5–86, in accordance with the recommendations issued, the same approach was used for blocks 5–84–86 and 5–88–90, as well as industrial experimental block 1–75–79. Due to the involvement in the production of substandard ores, the raw material base for the extraction of metals, at the operating mines, can be increased by 1.4–1.6 times.
The research results can be used in underground mining of ore deposits of complex structure in Ukraine, the Russian Federation, the Republic of Kazakhstan and other developed mining countries of the world.
Effect of heat treatment with biopreparation on the quality of tomato fruit during storage
Authors: Priss Olesia , Zhukova Valentina , Holiachuk Serhii , Karman Tetiana 
Published: July 2021

Tomato fruits are characterized by a high content of biologically active substances, which makes them an irreplaceable component of nutrition. However, tomatoes are perishable products and require additional measures to extend storage. One of the most problematic areas is the limited use of synthetic chemicals for processing fruit prior to storage. An alternative to them are natural exogenous preparations with antioxidant and disinfectant effects, which are environmentally friendly. However, the treatment of fruits with natural substances does not have sufficient efficiency in comparison with synthetic ones, which requires a combination with other post-harvest measures to increase cold stress. The object of research is the process of storing tomato fruits using heat treatment with a biological product. Numerous studies indicate the feasibility of using the processing of fruits with biological products to extend their storage duration. Standardized preparations based on bee products are of great interest. The research carried out in this work is aimed at extending the shelf life of tomato fruits while maintaining their quality by heat treatment of tomatoes with a solution of a biological product (tincture of the biomass of the larvae of the greater wax moth) before storage. In the course of the study, it was found that such treatment prolongs the shelf life of blank tomatoes up to 50 days, which is 40 % longer compared to the control. It has been proven that fruits treated with a biological product demonstrate a low level of metabolic processes. This is due to the fact that the proposed treatment slows down the rate of accumulation and degradation of sugars and organic acids. In particular, in fruits treated with a biological product, the sugar content is 8.8–10.6 % higher than in the control. The rate of decrease in the level of titratable acidity in the variants treated with the biological product is 15–19 % slower than in the control. The above results indicate the effectiveness of the use of a biological product for storing tomato fruits in comparison with similar measures.
O ENSINO DE GEOGRAFIA SOB UMA PERSPECTIVA CRÍTICA E REFLEXIVA
Authors: Dantas George Luiz Carneiro , Carvalho Neto Eulália Raquel Gusmão de 
Published: July 2021

A educação sistematizada, mais do que nunca, cumpre importante papel de socialização reflexiva e crítica. Assim, o presente artigo tem como objetivo discutir o ensino e a aprendizagem da geografia. Toma como referência uma investigação desenvolvida durante experiências vivenciadas no chão da escola, proporcionada pelo Programa Institucional de Bolsas de Iniciação à Docência – PIBID. Tal investigação adota a observação participante apoiada na pesquisa qualitativa e fundamenta-se na pedagogia crítica. Portanto, a discussão encontra-se assim organizada: no primeiro momento faz uma discussão sobre o ensino da geografia; posteriormente apresenta um relato de uma das experiências e para finalizar busca responder aos seguintes questionamentos: como o fazer docente pode transforma-se em uma prática onde a reflexão e análise crítica dos assuntos estudados seja uma constante entre professores e alunos? De que maneira o ensino da geografia pode realizar-se como uma prática dialética que promova a interação social? Conclui que a aula de campo como estratégia metodológica é uma excelente aliada dos livros didáticos, pois preenche lacunas e amplia os horizontes diante dos conceitos estudados. Depreende que o planejamento é fundamental para o seu sucesso e que o ensino da geografia quando fundamentado pela pedagogia crítica, possibilita a formação ética, o desenvolvimento intelectual e o pensamento crítico do educando. Torna-se dinâmico e transformador.
Attenuation of coda waves in the Dead Sea region
Authors: Eck Torild van 
Published: July 2021

AbstractCoda waves of local small earthquakes in the Dead Sea region, part of the Jordan rift structure, show frequency invariant codas, that is Qc = Q0(f/f0)n, with Q0 = 65 ± 5, f0 = 1 Hz and n = 1.05 ± 0.04 for hypocentral distances between 10 and 55 km, and lapse times less than 60 sec. This justifies, for example, the use of part of the coda for relative site response studies. Lacking direct Qβ measurements, Qc might be considered as a first approximation of Qβ for the region. For short hypocentral distances, r &lt; 20 km, rapidly increasing Qc with lapse time, t, has been observed.
Lg magnitudes and yield estimates for underground Novaya Zemlya nuclear explosions
Authors: Nuttli Otto W. 
Published: July 2021

Abstract
Lg-wave amplitudes of 30 Novaya Zemlya underground nuclear explosions, as recorded by short-period seismographs in Denmark, Finland, Germany, Norway, Spitsbergen, and Sweden, are used to determine mb(Lg) values. Assuming that the mb(Lg) versus explosion yield relation derived from Nevada Test Site data applies to all continental areas, the yields of the explosions are estimated. They cover a large range of values, from 2.5 to 4900 kt. The largest explosion since April 1976 had an estimated yield of 145 kt.
The mb(Lg) values, when subtracted from the mb(P) values, can be used to estimate the mb(P) bias between two test sites. In this way, the mb(P) bias between Novaya Zemlya and the Nevada Test Site is estimated to be 0.20 magnitude units.
Triggered slip along the San Andreas fault after the 8 July 1986 North Palm Springs earthquake
Authors: Williams Patrick L. , McGill Sally Fagerson , Sieh Kerry E. , Allen Clarence R. , Louie John N. 
Published: July 2021

Abstract
In addition to minor surface cracks in the region of the 8 July 1986 North Palm Springs earthquake, minor aseismic surficial rupture occurred along three segments of the San Andreas fault, 44 to 86 km southeast of the epicenter. Data from a creepmeter and a tiltmeter at one locality suggest that triggered slip occurred coseismically beneath the instruments but took 33 hr to propagate to the surface. That slippage occurred coseismically at depth favors mechanisms for triggered slip that involve dynamic or static strain changes rather than creep migrating from the source region.
The distribution of slip along the San Andreas fault associated with the North Palm Springs earthquake differed significantly from that recorded after the moderate 1968 Borrego Mountain, California and 1979 Imperial Valley, California, earthquakes. During these earthquakes, triggered slip occurred along the San Andreas fault in the Durmid Hill area and in the Mecca Hills. Triggered slip associated with the North Palm Springs earthquake occurred in these two areas again, but also extended farther northwest into the Indio Hills, where as much as 9 mm of dextral slip occurred. In the Mecca Hills, surface cracks in 1986 appeared over a shorter fault length than in previous events, and the dextral displacement was smaller, with maximum values of only 2 to 3 mm. On Durmid Hill, surface cracks in 1986 were localized along a 200-m-long stretch of the fault spanning the Mecca Beach creepmeter and extending about 150 m to the southeast. Right-lateral displacements on surface cracks in this area were 1.4 to 2.0 mm, smaller than those observed in previous events.
Although the mechanism of triggered aseismic slip is poorly understood, examination of displacement rates for the past several decades to centuries may indicate whether the aseismic slip rate is constant or represents accelerating premonitory failiure of the southernmost San Andreas fault.
Modeling teleseismicSVwaves from underground explosions with tectonic release: Results for Southern Novaya Zemlya
Authors: Cohee Brian P. , Lay Thorne 
Published: July 2021

AbstractDetailed forward modeling of long-period shear waves for two large underground explosions at the Southern Novaya Zemlya test site indicates that the appropriate equivalent double-couple orientation for the tectonic release radiation is vertical strike-slip. Previous studies of observed teleseismic SH waveforms and SV amplitudes for the 27 October 1973 and 2 November 1974 events using geometric ray theory could not distinguish between vertical strike-slip and 45°-dipping thrust geometries. Either mechanism can match the observed four-lobed SH radiation pattern, and the two-lobed SV amplitude pattern can be produced by interference with an appropriate size explosion pS signal. However, the complexity of the observed SV waveforms arising from Sp conversions near the receiver, diffracted Sp, and shear-coupled PL phases is not accounted for in the ray theory synthetics. Incorporating more realistic Green's functions using Baag and Langston's (1985b) WKBJ spectral method allows more complete modeling of the SV signals. Due to differences in frequency content between the explosion and double-couple SV waveforms, constructive interference occurs more efficiently than destructive interference when the two signals are linearly superimposed. As a result, using tectonic release moments determined from the SH waves and the optimum F factors required to match the SV amplitude patterns, the waveforms produced by the strike-slip and thrust orientations differ substantially at some azimuths. The strike-slip solution yields a consistently superior match to the data. Using the EU2 model of Lerner-Lam and Jordan (1987) for the source region and either EU2 or TNA (Grand and Helmberger, 1984) for the receiver structure, together with an attenuation model similar to SL8, we obtain a double-couple moment, M0 = 3.2 × 1024 dyne-cm and explosion source strength, ψ∞ = 3.8 ± 0.5 × 1011 cm3 for the 27 October 1973 event, and M0 = 1.7 × 1024 dyne-cm and ψ∞ = 2.0 ± 0.3 × 1011 cm3 for the 2 November 1974 event. Complete waveform modeling of SV signals can thus provide improved constraints on tectonic release radiation and explosion source strength.
Quasi-continental oceanic structure beneath the Arabian Fan sediments from observed surface-wave dispersion studies
Authors: Singh D. D. 
Published: July 2021

AbstractThe fundamental and higher modes of surface waves generated by 31 earthquakes and recorded at seismographic stations along the western margins of India and Pakistan (Trivandrum, Kodaikanal, Goa, Bombay, Poona, New Delhi, Nillore, and Quetta) are used to estimate the crustal structure beneath the Arabian Fan sediments. The sedimentary thickness is determined from the observed higher mode data. The observed dispersion data suggest an increase in crustal thickness northward, from an approximately 16 km crustal thickness at the southern tip of India (Trivandrum) to an approximately 28 km crustal thickness at the regions of 20°N and above latitude, with an overlying 6 km sedimentary thickness. This gradual increase in crustal thickness in the northward direction and the attaining of quasi-continental oceanic (transition from continent to ocean) structure beneath the Arabian Fan sediments suggest that the Mohorovičić discontinuity may have resulted from a change in crystal structure due to increase of pressure and not a phase change. The same material exists beneath the Moho, and it does not represent the boundary between two different materials. The transition has given rise to crustal thickening in the northward direction. Another possible explanation is that the increase in hydrostatic pressure due to the load exerted by a large sedimentary column together with horizontal pressure caused by the collision of Indian and Eurasian plates has given rise to an increase in temperature near the Moho. Because of the thermal blanketing effect of this large sedimentary column, an inferred rise in temperature may have either changed the upper mantle into material with crustal-like velocity or may have given rise to metamorphism of earlier existing sedimentary rocks. An inferred high temperature near the Moho depth beneath the Arabian Fan sediments is in close agreement with the high attenuating zone at the shallow depth (30 to 45 km) as determined by Singh (1987).
Elastic-wave propagation and site amplification in the Salt Lake valley, Utah, from simulated normal faulting earthquakes
Authors: Benz Harley M. , Smith Robert B. 
Published: July 2021

AbstractThe two-dimensional seismic response of the Salt Lake valley to near- and far-field earthquakes has been investigated from simulations of vertically incident plane waves and from normal-faulting earthquakes generated on the basin-bounding Wasatch fault. The response to normal faulting earthquakes was simulated using a two-dimensional finite-element method and the plane-wave response was calculated from two-dimensional finite-difference simulations. The plane-wave simulations were then compared with observed site amplifications in the Salt Lake valley, based on seismic recordings from nuclear explosions in southern Nevada, that show 10 times greater amplification within the basin than measured values on hard-rock sites. While previous studies attribute this increased site amplification to the near-surface unconsolidated/consolidated alluvial fill contact, our synthetic seismograms suggest that in the frequency band 0.3 to 1.5 Hz at least one-half the site amplification can be attributed to the impedance contrast between the basin sediments and higher velocity basement rocks. Synthetic seismograms from vertically incident plane-wave sources and buried double-couple sources predict large amplitude Rayleigh-wave propagation from the edges of the basin and, in general, uniform site amplification. In contrast, near-field simulations of basin-bounding, normal-faulting earthquakes predict large-amplitude Rayleigh waves propagating westward from the fault across the basin. Spectra of synthetic accelerograms computed from the normal-faulting earthquakes shows that spectral amplification within the basin is primarily due to source directivity with a maxima near the surface projection of the fault that decays rapidly away from the fault. Importantly, the synthetic modeling of near-field earthquake sources show that near-field directivity effects are important and should be considered in an earthquake hazard assessment of the Salt Lake valley and similar geologic settings along the Wasatch Front.
Pulse propagation in random media by a causal approach
Authors: Beltzer Abraham I. , Wegner Joanne , Tittman Bernard R. , Haddow James B. 
Published: July 2021

Abstract
A causal approach is applied to investigate pulse propagation in random media, which exhibit scattering and viscoelastic losses. Since the approach allows for evaluation of the effective wave number for the entire frequency interval, the transients may be investigated by the classical Fourier method. The scattering mechanism is described by a model introduced by Wu, and the viscoelastic losses by a slightly modified Azimi's law. Extensive numerical results for a transient response of this Wu-Azimi model are presented. It is shown how the pulse reinforcing and delaying effects of multiple scattering are interrelated through a causality constraint.
Network calibration forLgmagnitude—method and test results from eastern Canada
Authors: Chun Kin-Yip , Kokoski Richard J. , West Gordon F. 
Published: July 2021

AbstractWe present a method of calibrating a regional network of seismographic stations for Lg-wave site responses. Characterized by remarkable simplicity and practicality, the calibration procedure involves merely the determination of what we call calibration curves, defined as the frequency-dependent station site responses relative to that of a reference station. The method is used to calibrate a group of twelve stations belonging to the Eastern Canada Telemetered Network (ECTN), with an SRO-type station (GAC) serving as a reference station. The calibration curves are employed in a test application to Lg amplitude data from 50 small- to moderate-sized earthquakes (mLg (f) between 1.4 and 5.3). We found that use of the calibration curves leads to a systematic reduction in the variance of the station magnitude estimates of 37 per cent. A calibrated network minimizes station-specific systematic biases between the network magnitudes and those determined at any given station. As a result, it allows meaningful applications of empirically developed magnitude/yield relationship for stimulation of underground nuclear explosion yields, even when they are well recorded at very few stations of an in-country monitoring network.
A comparative study of island, seafloor, and subseafloor ambient noise levels
Authors: Hedlin Michael A. H. , Orcutt John A. 
Published: July 2021

AbstractA study of seafloor and island stations shows that for the frequency band 0.1 to 10 Hz the seismic noise levels on islands are comparable to the levels on the seafloor. The microseism peak at the seafloor appears to be comparable to the highest levels observed on small islands. For this band, seafloor stations are realistic alternatives when island sites are not available.Seven year averages of the ambient noise levels recorded by Seismic Research Observatory (SRO) stations on three islands (Guam [GUMO], Taiwan [TATO], and New Zealand's north island [SNZO]) are compared with those recorded by the International Deployment of Accelerometers (IDA) station on Easter Island and on and beneath the ocean floor by Ocean Bottom Seismometers (OBSs) and the Marine Seismic System (MSS) deployed in a south Pacific DSDP drill hole at 23.8°S., 165.5°W (Adair et al., 1986). From 0.3 to 2 Hz the SRO displacement power levels fall in the range historically observed by the Scripps' OBSs (decreasing at 70 dB/decade from 1 by 106 nm2/Hz at 0.3 Hz to 1 nm2/Hz at 2 Hz) and are 10 to 15 dB above MSS levels. Above 2 Hz it appears that the same ratios hold (the SRO power levels decrease at 70 dB/decade to 1 by 10−3 nm2/Hz at a frequency of 10 Hz), although this correlation is based on very limited, high gain, short-period data. At frequencies below 0.3 Hz the SRO noise levels peak and decrease to approximately 2 by 103 nm2/Hz at 40 mHz. The noise levels recorded at Easter Island are somewhat higher (decreasing at 70 dB/decade from 1 by 107 nm2/Hz at 0.2 Hz to 1 nm2/Hz at 10 Hz and to 1 by 105 nm2/Hz at 50 mHz). At the microseism peak near 0.2 Hz the MSS levels are from 15 to 20 dB higher than observed by the SRO stations and equivalent to those recorded at Easter Island. There appears to be little dependence of the variance in noise level estimates on frequency. The upper 95 per cent confidence limit generally lies 10 dB above the average noise levels for all island stations.All island noise level curves are dominated by the broad double-frequency microseism peak centered between 0.15 to 0.2 Hz. The single-frequency peak ranges from absent (Easter Island) to discernable (Guam and New Zealand) to obvious (at Taiwan). The center frequency of this peak ranges from 0.07 Hz at Guam and New Zealand to 0.1 Hz at Taiwan. We speculate that the increased amplitude and frequency of the single-frequency microseism peak is due to the interaction between the shallow continental shelf and surface gravity waves and/or the presence of Taiwan in a region of limited fetch.
Pre-earthquake displacement and triggered displacement on the Imperial fault associated with the Superstition Hills earthquake of 24 November 1987
Authors: Sharp Robert V. 
Published: July 2021

AbstractTwo right-lateral slip events, about 3 weeks apart in November 1987, broke the surface discontinuously along probably similar, nearly 20 km lengths of the northern Imperial fault. The first displacement, at about the beginning of November, was accompanied by a surface tilt representing deep vertical motion or distributed strain. This movement may have been part of a more regional event that also involved the southern San Andreas fault, although the evidence there is questionable. The later surface offset was triggered, probably by the second main shock of the 24 November earthquakes located in the Superstition Hills, about 37 km northwest of the Imperial fault. The maximum observed displacement was less than 4 cm on both occasions; for the triggered movement the maximum slip occurred on a branch strand near the northern extremity of the fault.Pre-earthquake resurveys of short-length leveling lines indicated combined surface displacement and an eastward tilt at two locations between surveys 712 months apart and 13 months apart; the tilt at Harris Road during this pre-earthquake interval is modeled as a 1.4 cm vertical component of slip deeper than 100 m on a 70° northeastward-dipping fault. Later resurveys showed a marked reduction of deep movement in the time period including the triggered slip, and between December 1987 and January 1988, it had ceased.No definite evidence of surface fracturing was found in the Brawley fault zone during either period of time when the Imperial fault moved. Remeasurement of leveling lines there indicated small, very near-surface vertical components of movement in the northern half of the zone. Elevation changes in the southern part indicated distributed strain and/or movement only deeper than about 50 m. The Brawley zone changes are not fixed in time well enough to clearly relate them to the surface movements on the Imperial fault.