An experimental study of source motion synthesis from first arrivals

1963 ◽  
Vol 53 (5) ◽  
pp. 955-963
Author(s):  
Henry N. Pollack
Keyword(s):  
Experimental Study ◽  
Source Function ◽  
Seismic Source ◽  
The Body ◽  
Body Waves ◽  
Fixed Position ◽  
Explosive Source ◽  
Simple Medium ◽  
Surface Ice ◽  
Source Motion

Abstract The motion near a seismic source is synthesized from experimentally obtained seismograms of non-dispersed body waves. The body waves were emitted from an explosive source submerged in a lake with a frozen surface. The seismograms were recorded at several distances by moving the source to a greater depth for each record, while the seismometer remained in a fixed position on the surface ice sheet. All syntheses of the waveform one meter from the source yield the impulsive nature of the source. Deviations between the synthesized one-meter record and the observed one-meter motion are thought to reflect primarily the changing character of the shot medium with depth from the ice. These results indicate that over the short propagation distances (about three wavelengths for the higher frequencies recorded) through the simple medium of this experiment, the observed waveforms and their associated spectra retain characteristics of the source function. The records also yield some information regarding the nature and structure of the elastic medium about the source.

scholarly journals The body waves due to a general seismic source in a layered earth model: 1. Formulation of the theory

1976 ◽  
Vol 66 (6) ◽  
pp. 1805-1819
Author(s):  
T. C. Bache ◽  
D. G. Harkrider
Keyword(s):  
Transfer Functions ◽  
Numerical Models ◽  
Homogeneous Medium ◽  
Seismic Source ◽  
Source Model ◽  
The Body ◽  
Body Waves ◽  
General Character ◽  
Earth Model ◽  
Equivalent Source

abstract The radiation field exterior to any kind of volume source in a homogeneous medium can be represented in terms of an expansion in spherical harmonics. Such an expansion then provides an equivalent elastic source representation of quite general character in that nearly any proposed seismic source model, whether obtained using analytical or numerical (finite difference or finite element) methods, can be written in this form. The compatibility of this equivalent source with currently used source models, especially numerical models including detailed computations of the nonlinear processes at the source, is discussed. The equivalent source is then embedded in a stack of plane elastic layers representing the near-source crustal geology, and expressions are derived for computing the steeply emergent body waves exiting the base of the model. These displacements can then be combined with transfer functions representing the effect of the remainder of the travel path to compute theoretical seismograms for the body waves recorded in the far-field.

scholarly journals Slithering CSF: Cerebrospinal Fluid Dynamics in the Stationary and Moving Viper Boa, Candoia aspera

Biology ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 672
Author(s):  
Bruce A. Young ◽  
Skye Greer ◽  
Michael Cramberg
Keyword(s):  
Cerebrospinal Fluid ◽  
Cardiac Cycle ◽  
Low Frequency ◽  
Mean Amplitude ◽  
The Body ◽  
Body Waves ◽  
Lower Amplitude ◽  
Lateral Undulation ◽  
Recovery From Anesthesia ◽  
The Relationship

In the viper boa (Candoia aspera), the cerebrospinal fluid (CSF) shows two stable overlapping patterns of pulsations: low-frequency (0.08 Hz) pulses with a mean amplitude of 4.1 mmHg that correspond to the ventilatory cycle, and higher-frequency (0.66 Hz) pulses with a mean amplitude of 1.2 mmHg that correspond to the cardiac cycle. Manual oscillations of anesthetized C. aspera induced propagating sinusoidal body waves. These waves resulted in a different pattern of CSF pulsations with frequencies corresponding to the displacement frequency of the body and with amplitudes greater than those of the cardiac or ventilatory cycles. After recovery from anesthesia, the snakes moved independently using lateral undulation and concertina locomotion. The episodes of lateral undulation produced similar influences on the CSF pressure as were observed during the manual oscillations, though the induced CSF pulsations were of lower amplitude during lateral undulation. No impact on the CSF was found while C. aspera was performing concertina locomotion. The relationship between the propagation of the body and the CSF pulsations suggests that the body movements produce an impulse on the spinal CSF.

Embodying the culture of achievement: Culture between illness and perfection is a ‘thin line’ – obtaining the ideal female body as an act of achievement

2021 ◽  
pp. 1354067X2110040
Author(s):  
Josefine Dilling ◽  
Anders Petersen
Keyword(s):  
Experimental Study ◽  
Human Body ◽  
Female Body ◽  
The Body ◽  
Thin Line ◽  
Complex Processes ◽  
The Individual ◽  
Different Levels ◽  
The Ideal ◽  
Body Ideals

In this article, we argue that certain behaviour connected to the attempt to attain contemporary female body ideals in Denmark can be understood as an act of achievement and, thus, as an embodiment of the culture of achievement, as it is characterised in Præstationssamfundet, written by the Danish sociologist Anders Petersen (2016) Hans Reitzels Forlag . Arguing from cultural psychological and sociological standpoints, this article examines how the human body functions as a mediational tool in different ways from which the individual communicates both moral and aesthetic sociocultural ideals and values. Complex processes of embodiment, we argue, can be described with different levels of internalisation, externalisation and materialisation, where the body functions as a central mediator. Analysing the findings from a qualitative experimental study on contemporary body ideals carried out by the Danish psychologists Josefine Dilling and Maja Trillingsgaard, this article seeks to anchor such theoretical claims in central empirical findings. The main conclusions from the study are used to structure the article and build arguments on how expectations and ideals expressed in an achievement society become embodied.

Seismic cone penetration test and seismic tomography in permafrost

2004 ◽  
Vol 41 (5) ◽  
pp. 796-813 ◽  
Author(s):  
Anne-Marie LeBlanc ◽  
Richard Fortier ◽  
Michel Allard ◽  
Calin Cosma ◽  
Sylvie Buteau
Keyword(s):  
Seismic Tomography ◽  
Dynamic Properties ◽  
Cone Penetration Test ◽  
The Body ◽  
Body Waves ◽  
Reconstruction Technique ◽  
Seismic Velocities ◽  
Penetration Test ◽  
Cone Penetration ◽  
Seismic Cone Penetration Test

Two high-resolution multi-offset vertical seismic profile (VSP) surveys were carried out in a permafrost mound near Umiujaq in northern Quebec, Canada, while performing seismic cone penetration tests (SCPT) to study the cryostratigraphy and assess the body waves velocities and the dynamic properties of warm permafrost. Penetrometer-mounted triaxial accelerometers were used as the VSP receivers, and a swept impact seismic technique (SIST) source generating both compressional and shear waves was moved near the surface following a cross configuration of 40 seismic shot-point locations surrounding each of the two SCPTs. The inversion of travel times based on a simultaneous iterative reconstruction technique (SIRT) provided tomographic images of the distribution of seismic velocities in permafrost. The Young's and shear moduli at low strains were then calculated from the seismic velocities and the permafrost density measured on core samples. The combination of multi-offset VSP survey, SCPT, SIST, and SIRT for tomographic imaging led to new insights in the dynamic properties of permafrost at temperatures close to 0 °C. The P- and S-wave velocities in permafrost vary from 2400 to 3200 m/s and from 900 to 1750 m/s, respectively, for a temperature range between –0.2 and –2.0 °C. The Young's modulus varies from 2.15 to 13.65 GPa, and the shear modulus varies from 1.00 to 4.75 GPa over the same range of temperature.Key words: permafrost, seismic cone penetration test, vertical seismic profiling, seismic tomography, dynamic properties.

MENGESAN KEWUJUDAN JIN BERDASARKAN PERUBAHAN WARNA AURA

2017 ◽  
Vol 5 (2) ◽  
pp. 36-49
Author(s):  
YOHAN KURNIAWAN ◽  
ALEXANDER STRAK ◽  
BURHAN BIN CHE DAUD ◽  
HISHAMUDDIN MD. SOM ◽  
ABDUL AZIZ BIN SUAIB
Keyword(s):  
Experimental Study ◽  
Data Collection ◽  
The Body ◽  
Data Collection Methods ◽  
Red Color ◽  
Holy Quran ◽  
The Holy Quran ◽  
Color Data ◽  
Source Of Information ◽  
Collection Methods

Kewujudan jin merupakan suatu kepercayaan yang telah lama wujud dalam kalangan masyarakat Melayu di Nusantara, khususnya di Malaysia. Kewujudan jin telah diterangkan secara jelas dalam kitab suci Al-Quran. Walaupun terdapat sumber maklumat yang sahih akan tetapi kewujudan jin ini belum dapat dibuktikan secara saintifi k. Kajian yang dijalankan ini bertujuan untuk mengenal pasti dan memahami fenomena kewujudan jin berdasarkan warna aura. Kajian yang dijalankan merupakan kajian eksperimental dan melibatkan seorang responden yang memiliki saka. Kaedah pengumpulan data yang digunakan dalam kajian ini adalah perubahan warna aura dan temu bual. Peralatan kajian yang digunakan adalahperalatan WinAura untuk mendapatkan data perubahan warna aura, dan peralatan rakaman untuk data temu bual. Hasil kajian mendapati kewujudan jin dalam badan seseorang ditandai dengan warna merah yang wujud secara tiba-tiba dan konsisten pada bahagian badan tertentu terutamanya pada bahagian dahi, tekak atau pada bahagian badan sebelah kiri. Hasil temu bual mendapati rawatan perubatan Islam yang dilakukan oleh responden mengatakan bahawa terdapat jin dalam diri responden. Kajian ini berjaya membuktikan kewujudan jin dalam diri responden berdasarkan perubahan warna aura.   The existence of the jinn is a phenomena that has long existed among the Malay community in Nusantara, especially in Malaysia. The existence of the jinn has been described clearly in the Holy Quran. Although there is a valid source of information, unfortunately the existence of the genie has not been scientifically proven. The study was aimed to identify and understand the phenomenon of jinn existence based on aura color. The study was an experimental study and involved a respondent who has saka. Data collection methods were used in this study was aura change color and interview. The equipments was used in this research were the WinAura machine to obtain of changing color data of the aura. The study found that the existence of genie in a person’s body was characterized by suddenly and consistent appear of red color in certain parts of the body, especially on the forehead, throat or on the left side of the body. The interviews also found that the characteristics and experience that the respondent’s surrounding and the there are energy or strength that followed respondent. This study proved the existence of supernatural beings (genie) based on aura change color.

A dynamic model for far-field acceleration

1982 ◽  
Vol 72 (4) ◽  
pp. 1049-1068
Author(s):  
John Boatwright
Keyword(s):  
Stress Drop ◽  
High Frequency ◽  
Dynamic Stress ◽  
The Body ◽  
Body Waves ◽  
Far Field ◽  
Rupture Velocity ◽  
Frequency Level ◽  
Average Change ◽  
Dynamic Stress Drop

abstract A model for the far-field acceleration radiated by an incoherent rupture is constructed by combining Madariaga's (1977) theory for the high-frequency radiation from crack models of faulting with a simple statistical source model. By extending Madariaga's results to acceleration pulses with finite durations, the peak acceleration of a pulse radiated by a single stop or start of a crack tip is shown to depend on the dynamic stress drop of the subevent, the total change in rupture velocity, and the ratio of the subevent radius to the acceleration pulse width. An incoherent rupture is approximated by a sample from a self-similar distribution of coherent subevents. Assuming the subevents fit together without overlapping, the high-frequency level of the acceleration spectra depends linearly on the rms dynamic stress drop, the average change in rupture velocity, and the square root of the overall rupture area. The high-frequency level is independent, to first order, of the rupture complexity. Following Hanks (1979), simple approximations are derived for the relation between the rms dynamic stress drop and the rms acceleration, averaged over the pulse duration. This relation necessarily depends on the shape of the body-wave spectra. The body waves radiated by 10 small earthquakes near Monticello Dam, South Carolina, are analyzed to test these results. The average change of rupture velocity of Δv = 0.8β associated with the radiation of the acceleration pulses is estimated by comparing the rms acceleration contained in the P waves to that in the S waves. The rms dynamic stress drops of the 10 events, estimated from the rms accelerations, range from 0.4 to 1.9 bars and are strongly correlated with estimates of the apparent stress.

scholarly journals Musculoskeletal disorders among robotic surgeons: A questionnaire analysis

2014 ◽  
Vol 86 (2) ◽  
pp. 95 ◽  
Author(s):  
Claudio Giberti ◽  
Fabrizio Gallo ◽  
Luca Francini ◽  
Alessio Signori ◽  
Marco Testa
Keyword(s):  
Musculoskeletal Disorders ◽  
Surgical Outcomes ◽  
Negative Impact ◽  
Negative Influence ◽  
The Body ◽  
Sitting Position ◽  
Body Parts ◽  
Upper Limbs ◽  
Fixed Position ◽  
Prolonged Sitting

Objective: Robotic surgical systems offer better workplace in order to relieve surgeons from prolonged physical efforts and improve their surgical outcomes. However, robotic surgery could produce musculoskeletal disorders due to the prolonged sitting position of the operator, the fixed position of the console viewer and the movements of the limbs. Until today, no one study has been reported concerning the association between robotics and musculoskeletal pain. The aim of this work was verify the prevalence of musculoskeletal disorders among Italian robotic surgeons. Material and methods: Between July 2011 and April 2012 a modified Standardized Nordic Questionnaire was delivered to thirty-nine Italian robotic centres. Twentytwo surgeons (56%) returned the questionnaires but only seventeen questionnaires (43.5%) were evaluable. Results: Seven surgeons (41.2%) reported musculoskeletal disorders, by since their first use of the robot which significantly persisted during the daily surgical activity (P < 0.001). Regarding the body parts affected, musculoskeletal disorders were mainly reported in the cervical spine (29.4%) and in the upper limbs (23.5%). Six surgeons (35.3%) defined the robotic console as less comfortable or neither comfortable/uncomfortable with a negative influence on their surgical procedures. Conclusions: In spite of some important limitations, our data showed musculoskeletal disorders due to posture discomfort with negative impact on daily surgical activity among robotic surgeons. These aspects could be due to the lack of ergonomic seat and to the fixed position of the console viewer which could have produced an inadequate spinal posture. The evaluation of these postural factors, in particular the development of an integrated and more ergonomic chair, could further improve the comfort feeling of the surgeon at the console and probably his surgical outcomes.

scholarly journals Long-period mechanism of the 8 November 1980 Eureka, California, earthquake

1982 ◽  
Vol 72 (2) ◽  
pp. 439-456
Author(s):  
Thorne Lay ◽  
Jeffrey W. Given ◽  
Hiroo Kanamori
Keyword(s):  
Point Source ◽  
Seismic Moment ◽  
Moment Tensor ◽  
Strike Slip ◽  
The Body ◽  
Body Waves ◽  
Long Period ◽  
Amplitude Data ◽  
The Moment ◽  
Scalar Moment

Abstract The seismic moment and source orientation of the 8 November 1980 Eureka, California, earthquake (Ms = 7.2) are determined using long-period surface and body wave data obtained from the SRO, ASRO, and IDA networks. The favorable azimuthal distribution of the recording stations allows a well-constrained mechanism to be determined by a simultaneous moment tensor inversion of the Love and Rayleigh wave observations. The shallow depth of the event precludes determination of the full moment tensor, but constraining Mzx = Mzy = 0 and using a point source at 16-km depth gives a major double couple for period T = 256 sec with scalar moment M0 = 1.1 · 1027 dyne-cm and a left-lateral vertical strike-slip orientation trending N48.2°E. The choice of fault planes is made on the basis of the aftershock distribution. This solution is insensitive to the depth of the point source for depths less than 33 km. Using the moment tensor solution as a starting model, the Rayleigh and Love wave amplitude data alone are inverted in order to fine-tune the solution. This results in a slightly larger scalar moment of 1.28 · 1027 dyne-cm, but insignificant (<5°) changes in strike and dip. The rake is not well enough resolved to indicate significant variation from the pure strike-slip solution. Additional amplitude inversions of the surface waves at periods ranging from 75 to 512 sec yield a moment estimate of 1.3 ± 0.2 · 1027 dyne-cm, and a similar strike-slip fault orientation. The long-period P and SH waves recorded at SRO and ASRO stations are utilized to determine the seismic moment for 15- to 30-sec periods. A deconvolution algorithm developed by Kikuchi and Kanamori (1982) is used to determine the time function for the first 180 sec of the P and SH signals. The SH data are more stable and indicate a complex bilateral rupture with at least four subevents. The dominant first subevent has a moment of 6.4 · 1026 dyne-cm. Summing the moment of this and the next three subevents, all of which occur in the first 80 sec of rupture, yields a moment of 1.3 · 1027 dyne-cm. Thus, when the multiple source character of the body waves is taken into account, the seismic moment for the Eureka event throughout the period range 15 to 500 sec is 1.3 ± 0.2 · 1027 dyne-cm.

scholarly journals El papel de las experiencias escolares preuniversitarias en la conformación de un proyecto de vida ligado a la educación superior en estudiantes con discapacidad

2016 ◽  
Vol 20 (2) ◽  
pp. 1 ◽  
Author(s):  
Rodolfo Cruz-Vadillo ◽  
Miguel Ángel Casillas-Alvarado
Keyword(s):  
Higher Education ◽  
Experimental Study ◽  
Data Collection ◽  
Students With Disabilities ◽  
Structured Interview ◽  
School Experiences ◽  
The Body ◽  
Positive Experience ◽  
Right To Education ◽  
Audio Recordings

This article aims to approach the school experiences of 13 students with disabilities. It corresponds to a cross, synchronous and non experimental study, whose scope is mainly descriptive. The data collection was carried out through a semi-structured interview and transcribed from audio recordings to make a category analysis. The main results showed that in the case of students who were born with disabilities, the fact that an institution was inclusive turned out essential for them to have adequate transit through the educational system and thus become apt for higher education. The combination disability-inclusion-right to education-higher education is what this paper aimed to weave, trying to follow as thread or anchor, the previous school experiences of students with disabilities. We recognize that an adequate, inclusive, positive experience besides a subjective construction of the body and disability by family members, become important conditions to access schooling. Education is a right, therefore it can not be seen as an act of charity; it should be required as a quality practice.

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