bluuebunny/crossref_metadata_2025_split huggingface dataset:
Proposed use of the T phase in tsunami warning systems*
Authors: Ewing Maurice , Tolstoy Ivan , Press Frank 
Published: May 2021

AbstractA striking correlation between the occurrence of a short-period earthquake phase (T phase) traveling through the ocean with the speed of sound in sea water and the occurrence of tsunamis has been observed. The characteristics of the T phase are described and the data upon which the correlation is based are presented. Although further study is needed, the evidence at hand warrants the inclusion of instruments suitable for recording the T phase in tsunami warning systems. It is quite possible that SOFAR listening stations would be valuable adjuncts in the detection of tsunami-producing earthquakes since they offer the best means of recording the T phase.
The application of feedback to an electromechanical transducer for seismograph testing*
Authors: Honnell Pierre M. 
Published: May 2021

Summary
The application of feedback to an electromechanical transducer, or oscillating platform, designed for the testing of seismographs is described. Accruing advantages are the complete masking of the resonance peak in the transducer velocity response, and immunity of the platform motion to variations in mechanical loading by the seismographs undergoing test.
The superiority of the feedback technique is shown by direct comparison with the operation of the transducer electrically damped by a short-circuited ring.
The transducer constant-velocity output is easily converted to constant amplitude or constant acceleration by means of simple coupling networks.
Crustal structure and surface-wave dispersion*
Authors: Ewing Maurice , Press Frank 
Published: May 2021

Summary
The observed dispersion of Rayleigh waves across the Atlantic and Pacific oceans can be accounted for by considering the propagation of such waves through a system consisting of water and unconsolidated sediments overlying a thick layer of ultrabasic rock. This contrasts with all former treatments, which have considered the effect of the water layer to be negligible. The depth of the water-sediment layer and the speed of shear waves in the underlying ultrabasic layer are obtained for several paths across the Atlantic and Pacific oceans. The results for the Atlantic are in good agreement with the data obtained in a recent seismic refraction measurement made 120 miles northwest of Bermuda, and offer strong evidence that the result of this single refraction measurement will be found to be typical of the entire ocean. No significant difference in the nature of the suboceanic basement of the Atlantic and Pacific has been found, since the velocity of shear waves in the upper-most 50 to 100 km. was calculated to be 4.45 km/sec. for both oceans. Previously reported differences in Atlantic and Pacific velocities for Rayleigh waves of some selected period are now believed to be due primarily to differences in the depth of water plus sediment in the two oceans.
Travel times from blasts in southern California*
Authors: Gutenberg B. 
Published: May 2021

abstract
Seismograms recorded from a blast of about 70 tons of Du Pont “Nitramon” in tunnels at a quarry near Corona, southern California, are discussed. Arrival times of P waves indicate a velocity of between 5.7 and 6.0 km/sec. in the upper 6 km. of the region, and a velocity of about 6 1/2 km/sec. at a depth of 10 km. The Mohorovičić discontinuity is at a depth of the order of 40 km. The velocity below it is 8.1 to 8.2 km/sec. The amplitudes of S waves are only slightly more than one-tenth of those in an earthquake having P waves of equal amplitudes. The ratio of the velocity of P to that of the first recognizable S is found between 1.6 and 1.7. The first S waves at distances up to about 140 km. indicate a velocity of transverse waves of about 3¾ km/sec. at a depth of the order of 10 km. A phase with an apparent velocity of about 3 1/2 km/sec. can be traced to more than 400 km. It is followed by several slower phases. On the assumption that the amplitudes of Pn do not differ appreciably from those in an earthquake of the same magnitude, the blast would have had a magnitude of about 4.
The primary seismic disturbance in shale*
Authors: Ricker Norman , Sorge W. A. 
Published: May 2021

Abstract
This paper describes experimental researches carried out in a reasonably homogeneous earth for the purpose of determining the form and laws of propagation of the primary seismic disturbance. Flat response seismic apparatus was employed so that precise measurements of true earth motion were carried out. The results are in good agreement with the mathematical theory previously published.
Instrumental study of the Manix Earthquakes*
Authors: Richter C. F. , Nordquist J. M. 
Published: May 2021

Summary
Readings from seismograms of thirty-eight shocks occurring on the Mojave Desert near Manix, California, are tabulated, plotted, and discussed. For a large proportion of the shocks (Groups A and D), the most clearly identified seismic waves have travel times as follows (times in seconds, Δ in kilometers): p–O=D/6.34P–O=–1.2 + 0.1799 ΔPn–O=5.4 + 0.12195 Δs–O=D/3.67Pm–O=3.9 + 0.1427 ΔSn–O=9.0 + 0.220 ΔPy–O=1.2 + 0.1610 ΔSa–O=6.0 + 0.25 Δ
D is calculated from Δ assuming a depth of 16 km.
For the remaining shocks (Groups B and C), the constant terms in the equations for Pn, Pm, Py are increased to 6.0, 4.5, and 2.2, respectively; the other equations are unchanged, but D is calculated for a depth of 10 km.
The Group A shocks are assigned to four subgroups. Epicenters are as follows: GroupLat. NLong. WA1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34°57.5116°32′A2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3459.511633.5A3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .345811633A4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .350011634B. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .345611631C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3457.511632D. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .345311637
Epicenters A1 to B follow an alignment striking about N 30° W, crossing the Manix fault at a large angle. No shocks are located elsewhere along the Manix fault, but the smaller shocks cannot be placed accurately.
The principal earthquake, of magnitude 6.2, is assigned to the A2 epicenter, with origin time 07:58:05.6 P.S.T. (15:58:05.6 G.C.T.), April 10, 1947. This agrees well with the times recorded at distant stations. A catalogue is given listing all subsequent shocks of magnitude 3.0 or greater in the area to the end of April, 1950, with assignment to one of the groups when possible.
Recorded initial compressions and dilatations at the several stations are equally consistent with right-hand strike-slip on a hypothetical fault following the line of located epicenters, or with left-hand strike-slip on the Manix fault; the latter displacement was actually found. It is suggested that both occurred.
Representative seismograms are reproduced.
RURAL WOMEN’S EXPERIENCE OF LEISURE IN A GENDERED WORLD: A SOUTH ASIAN PERSPECTIVE
Authors: Hayat Muhammad Farhat , Ashiq Rukhsana 
Published: May 2021

Purpose of the Study: The main objective of this paper was to synthesize and analysing the existing knowledge to evaluate the effect of public space on women’s leisure. Another major objective was to check the role of gender in determining leisure activities and opportunities for rural women. The current study focuses on South Asian rural women concerning Pakistani society.
Methodology: For the present study, the researchers analysed and reviewed articles from different databases like Google Scholar, Taylor, and Francis, Springer, and Sage publication journals from 2000 to 2020.
Principal Findings: After reviewing the various studies conducted in the 21st century, the results showed that most rural women are not allowed to do leisure in public space, and they have few opportunities to do it inside the boundary of the household. The public space is used predominantly by males for their leisure. Family pressure and patriarchal social norms also hampered women’s desire to claim public space for leisure activities.
Application of the Study: This study concluded that the leisure opportunities for rural women are less as compared to their counterparts. Public space is vital and plays a pivotal role in shaping and determining leisure activities for both genders. This study also raised certain questions which are thought-provoking and can be crucial for future investigation.
Novelty/Originality: this study is a unique effort to discuss rural women’s leisure from a South Asian Perspective. It also gives insight with the support of most recent data regarding rural women’s leisure and its relationship with the social structure of society.
Bioimpedance phase angle as a marker of sarcopenia in elderly women with multiple comorbidities
Authors: Kurmayev D. P. , Bulgakova S. V. , Zakharova N. O. 
Published: May 2021

Rationale: The progressive decline in skeletal muscle strength and function during aging can lead to disability and premature death. It is of interest to evaluate the potential of bioimpedance phase angle (PhA) as an instrumental marker of sarcopenia in clinical practice.Aim: To identify an association between the phase angles determined by the bioimpedance analysis of body composition, with functional activity parameters in elderly women with multiple comorbidities.Materials and methods: The study included 146 elderly women (aged 75 to 84 years, mean age 79.44 ± 2.56 years). Assessments consisted of the Charlson comorbidity index, “Vozrast ne pomekha” (Age is not a hindrance) questionnaire, the Barthel index, the sit-to-stand five-repeat test, the standardized 4-meter walking speed test, and bioimpedance analysis of body composition (ABC-02, Medass, Russia). Muscle strength parameters were assessed by wrist dynamometry with a mechanical wrist dynamometer. The hand dynamometry index was calculated by dividing the hand grip strength by the patient's squared height. According to the EWGSOP2 guidelines for the critical cur-off for hand dynamometry, the patients were divided into two groups: those with the hand grip strength > 16 kg (n = 41) and those with < 16 kg (n = 105).Results: There were significant correlations of PhA with age (r = -0.369; p =0.017), the results of the screening questionnaire “Vozrast ne pome-kha” (Age is not a hindrance) (r = -0.359; p = 0.023), Barthel index (r = 0.375; p = 0.018), hand dynamometry (r = 0.395; p = 0.014), hand dynamometry index (r = 0.340; p = 0.021), lean body mass (r = 0.414; p = 0.009), musculoskeletal mass (r = 0.819; p < 0.001), proportion of musculoskeletal mass (r = 0.796; p < 0.001), walking speed (r = 0.670; p < 0.001), and the results of the sit-to-stand test (r = -0.541; p < 0.001). Sarcopenia was diagnosed in 61 women (41.8%). There were also significant differences in age, hand dynamometry results, hand dynamometry index, walking speed and results of the sit-to-stand test between the two groups depending on their hand grip strength.Conclusion: The use of hand dynamometry, physical activity tests, and bioimpedance phase angle can be used in clinical practice to diagnose sarcopenia.
Classification and Prediction of Students’ GPA Using K-Means Clustering Algorithm to Assist Student Admission Process
Authors: Santosa Raden Gunawan , Lukito Yuan , Chrismanto Antonius Rachmat 
Published: May 2021

Background: Student admission at universities aims to select the best candidates who will excel and finish their studies on time. There are many factors to be considered in student admission. To assist the process, an intelligent model is needed to spot the potentially high achieving students, as well as to identify potentially struggling students as early as possible.Objective: This research uses K-means clustering to predict students’ grade point average (GPA) based on students’ profile, such as high school status and location, university entrance test score and English language competence.Methods: Students’ data from class of 2008 to 2017 are used to create two clusters using K-means clustering algorithm. Two centroids from the clusters are used to classify all the data into two groups: high GPA and low GPA. We use the data from class of 2018 as test data. The performance of the prediction is measured using accuracy, precision and recall.Results: Based on the analysis, the K-means clustering method is 78.59% accurate among the merit-based-admission students and 94.627% among the regular-admission students.Conclusion: The prediction involving merit-based-admission students has lower predictive accuracy values than that of involving regular-admission students because the clustering model for the merit-based-admission data is K = 3, but for the prediction, the assumption is K = 2.
JUSTIFICATION OF TRANSPORT WORKS IN THE CONDITIONS OF A BLOCK QUARRY
Authors: KYRYLENKO Nina , SHAMRAI Volodymyr , KOVALEVYCH Liudmyla , LEBLYA Mykola , MAKHNO Artur 
Published: May 2021

The increase in oil prices, consumables and tools is necessitate the re–equipment of mining enterprises in Ukraine. The share of automobile transport reaches 35–50 % in the dimension blocks production costs.
The purpose of the work is to determine transportation costs (TC) of 1 m3 of blocks depending on the volume and transportation distance within the quarry; improving the transportation plan by solving transportation problems of linear programming.
Fuel consumption and dimension block TC for three models of front–end loaders (FEL) were newly calculated on the basis of a comprehensive study. A comparison of the economic feasibility of FEL and dump truck (DT) use in certain mining conditions have been made. The rationalization plan (RP) of dimension blocks transportation within the quarry was newly proposed.
The research was performed at the dimension gabbro quarry, blocks transportation in which is performed using FEL CAT 988F (1) and DT KrAZ–256B. FELs CAT 988H (2) and CAT 986H (3) were adopted for comparison.
The average annual fuel consumption is determined: among the FELs considered in the research, the (3) consumes the least, and the (1) currently used at the enterprise consumes 22.7 % and 9.7 % more fuel compared to the (3) and the (2), respectively, in similar conditions. Trade blocks transportation using FEL is economically more expedient in comparison with the DT at transportation distance up to 300–400 m.
It is determined that the trade blocks TC using the (2) and the (3) is 5.3 % and 12.6 % lower, respectively, compared to the (1).
This paper also considers the transportation problem for FELs, in which blocks from several banks must be distributed between several storage areas, provided to minimize TC. According to the proposed RP of transportation, the savings will be up to 13 % compared to the initial conditions, which in monetary terms is 41538–48639 UAH/year depending on the FEL model. The replacement of the (1) for the (3) will reduce block TC by 12.6 % (47000 UAH/year) in the current conditions. The TC using the (3) will be 285303.5 UAH according to the proposed RP, which is 23.7 % (88476 UAH/year) less than the (1) application before the rationalization.

Keywords: dimension stone; front–end loader; commercial blocks transportation costs; transportation problem; cargo traffic rationalization; fuel consumption; haul road gradient.
Interannual Variability in the Summer Season Onset, Length and End Dates Across the Iran (1948-2016)
Authors: Sedaghat Mahdi , Nazaripour Hamid 
Published: May 2021

Abstract
It is very important to study the role of global warming on the variability of summer characteristics in arid and semi-arid climates such as Iran, because of its impact on natural and social systems.The aim of this study is to detect interannual variability in the onset, end and duration of the summer season in Iran. To achieve this goal, three indices are defined: physical, dynamic and synoptic. Daily data of the Earth's surface temperature (°C), tropopause level pressure (hPa) and geopotential height at 1000 hectopascals (m) are the basis of physical, dynamic and synoptic indices, respectively. Data were extracted from the reanalysis databases for 1948 to 2016 in different domains. A three-variable dataset using regional mean values allowed researchers to determine the start date (onset) of the summer based on the following thresholds: Temperatures above 25°C and duration of 10 days (physical index), tropopause level pressure less than 120 hPa and duration of 10 days (dynamic index), geopotential height at 1000 hPa less than 50 m and duration of 10 days (synoptic index). The opposite situation indicates the end of summer. The results showed that the start and end of summer based on physical, dynamic and synoptic indices are May 11 and September 21, June 4 and October 1, May 20 and September 15, respectively. The average length of summer is 134, 120 and 119 days, respectively. Statistically significant long-term trends have been observed for the start and end dates of the summer season. Seasonal variability has accelerated significantly since the late the twentieth century. In short, the summer season in Iran tends to start early and end late. As a result, summer lengths are longer in 80 percent of the years after 1981 compared with less than 50 percent from 1948 to 1981.
How is the hyponatremia management in hospitalized patients? A cross-sectional study
Authors: Sánchez Jorge Gabriel Ruiz , Fernández-Cagigao Yvonne , Fuentes Beatriz De León , Parra-Ramírez Paola , Rojas-Marcos Patrica Martín , Álvarez-Escolá Cristina 
Published: May 2021

Abstract
Background: Hyponatremia is the most frequent hydroelectrolytic disorder in hospitalized patients and is associated with mortality. A lack in the diagnostic and therapeutic management of the hyponatremic hospitalized patient has been reported. Hyponatremia in hospitalized patients is usually managed by specialties other than nephrology and endocrinology. The aim of our study is to describe the diagnostic and therapeutic management of hyponatremia by clinicians from services other than endocrinology and nephrology in hospitalized patients.Methods: Cross-sectional, descriptive study of a consecutive case series of adult patients hospitalized with hyponatremia, in a tertiary hospital of Madrid, during January 1st-May 30th 2019, handled by non-endocrinologist nor nephrologist clinicians. We analyzed data regarding the details of the diagnostic assessment and the treatment established by the clinicians of the respective hospitalization service. Results: 32 cases studied, all of them with hypovolemic hyponatremia, 50% women, 50% managed in the emergency room. Volemic classification of hyponatremia was described in only 18.8%. The height of the internal jugular venous pulse was not measured in any case. Urine studies were developed in below 70% of cases. 50% of patients had a congruent treatment with the previous described volemic status. Only one case had a complete and successful diagnostic and therapeutic approach in accordance to clinical guidelines.Conclusion: In our series there was a lack in the diagnostic and therapeutic management of hyponatremia of hospitalized patients by non-endocrinologists and non-nephrologists.
Removal of Chromium(VI) from Aqueous Solution using a Strong base Anion Exchange Resin : Kinetic and Equilibrium Studies
Authors: REVANKAR HARISH NAGESH , KOUJALAGI PRASANNA S , GURJAR VIJAYENDRA R , KULKARNI RAVIRAJ M 
Published: May 2021

Abstract
The removal of chromium (VI) from aqueous solution using the strong base anion exchange resin Tulsion A-62 (MP) is reported in this study under a variety of experimental conditions, including initial chromium (VI) concentration, contact time, and medium pH. The ion-exchange process for the resin Tulsion A-62 (MP) was relatively simple and after 300 minutes of phase contact, the equilibrium was achieved. The sorption process, which is pH based, extracted the most chromium (VI) when the pH was between 4.0 and 5.0. Both Langmuir and Freundlich adsorption isotherms were used to fit the equilibrium results for Cr(VI) adsorption, however Langmuir isotherm model was found to be more acceptable for the Cr(VI) adsorption and maximum adsorption capacity of Cr(VI) was found to be 201.6 mg/g. Scanning Electron Microscopy with EDX and Fourier transformed infrared spectroscopy were also used to characterize Tulsion A-62 (MP) before and after chromium adsorption. The adsorption mechanism followed reversible first-order kinetics. The findings showed that such anion-exchange resins can be used to effectively extract chromium (VI) ions from water and wastewater.
Single / Dual-Band Frequency and Polarization Switching Using Frequency Selective Surfaces for Terahertz Applications
Authors: Mabrouk Ahmed Mosaad , Ibrahim Ahmed Abd Elmoneam , Hamed Hesham Fathi 
Published: May 2021

Abstract
This paper presents reconfigurable frequency and polarization FSS-based with photoconductive switches in a single and dual-band operation for antenna applications at the terahertz band. The single band FSS unit-cell element exhibits frequency reconfigurability between 0.62 THz and 0.7 THz. It also converts the LP waves into CP over a frequency band ranging from 0.59 THz to 0.8 THz (30 % 3-dB BW). The dual-band FSS unit-cell element exhibits frequency reconfigurability between (0.42 THz and 1.03 THz) when the switches are turned ON and (0.51 THz and 0.865 THz) when the switches are turned OFF. Moreover, it exhibits polarization conversion over two bands from 0.46 THz to 0.56 THz (20% 3-dB B.W) and from 0.82 THz to 0.91 THz (12 % 3-dB B.W). The dual-band FSS unit-cell element is arranged in a 7 x 7 array and used as a reflector for two dipole antennas (A and B) operating at 0.82 THz and 0.5 THz, respectively. The same dual-band FSS-based surface enhances their gain to about 8.4 dBi and converts their polarization from LP to CP at 0.82 THz and 0.5 THz, respectively.
Comparative Analysis of Water Quality Indices and Their Relationship with Anthropogenic Activities. Case Study: Bogotá River
Authors: Marimon Wilfredo , Jimenez Nathalie Toussaint , Jiménez Carlos , Chavarro John , Domínguez Efraín 
Published: May 2021

Abstract
The Water Quality Index is the numerical value that qualifies in categories, the water quality of a surface stream, based on the measurements obtained for a set of physicochemical and microbiological parameters registered in a water quality monitoring network. This indicator allows knowing the physical-chemical and microbiological quality conditions of a body of water and identifies contamination problems at a certain point. In the present study, the water quality was studied in 43 stations located in the Bogota river, considering different methodologies for calculating quality indices such as NSF, Oregon, IDEAM, Prati, and diffuse logic to establish the differences, advantages, and disadvantages of each method. Similarly, a correlation analysis was carried out between the parameters, and the land uses in the basin. The results indicated that all the indices showed regular or poor water quality for more than 80% of the stations for the temporal window studied. However, the methodology used in Colombia (ICA water quality index, in Spanish) has eclipsing problems in most of the evaluation points since where the water quality qualifies as good, other indices such as the fuzzy logic show a degree of contamination by any of the parameters mainly manganese or total suspended solids.