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Tytuł:
P wave duration and morphology in patients with atrial fibrillation
Autorzy:
Mercik, Jakub Szymon
Unkell, Malte
Marinov, Maxim
Wolff, Peter Stephan
Radziejewska, Jadwiga
Gajek, Jacek
Powiązania:
https://bibliotekanauki.pl/articles/1196135.pdf
Data publikacji:
2020-11-12
Wydawca:
Gdański Uniwersytet Medyczny
Tematy:
atrial fibrillation
P wave duration
P wave morphology
Bachmann's bundle
Opis:
Background: Functional and structural atrial changes contribute to AF. It decreases conduction velocity and forms intra atrial blocks. In the ECG those changes are manifested by the duration and morphology of the P wave. Material and method: The study group consisted of 50 patients with atrial fibrillation. There were 27 women and 23 men, aged 65.3 +/- 9.8 years. 22 patients had paroxysmal AF and 28 had persistent AF, in the latter direct current cardio version was performed. Results: In patients with a prolonged episodes of atrial fi- brillation the P wave duration was longer in comparison to patients with sinus rhythm (187.1 +/- 31.5 vs 161.1 +/- 18.8 ms; p = 0.006). There were significant differences in P wave duration among the patients with normal and abnormal interatrial conduction, with the longest duration in complete Bachmann's bundle block group (152.7 +/- 17.5 vs 165.3 +/- 15.3 vs 207.9 +/- 27.5 ms; p < 0.001). Conclusions: In patients with persistent atrial fibrillation the duration of the P wave is prolonged in comparison to paroxysmal. In the majority of patients prolongation of the P wave duration is dependent on different forms of conduction block. The morphological changes of P waves are caused by the arrhythmia rather than left atrial hypertrophy.
Źródło:
European Journal of Translational and Clinical Medicine; 2020, 3, 2; 22-28
2657-3148
2657-3156
Pojawia się w:
European Journal of Translational and Clinical Medicine
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The P wave duration in patients with atrial fibrillation undergoing cryoballoon pulmonary vein isolation. Preliminary results
Autorzy:
Zawadzki, Jacek Marcin
Adamowicz, Jakub
Sławuta, Agnieszka
Gajek, Aleksandra
Zyśko, Dorota
Gajek, Jacek
Powiązania:
https://bibliotekanauki.pl/articles/895835.pdf
Data publikacji:
2018-09-28
Wydawca:
Gdański Uniwersytet Medyczny
Tematy:
P wave duration
P wave dispersion
cryoablation
atrial fibrillation
pulmonary veins isolation
Opis:
The pulmonary vein isolation remains the major target of atrial fibrillation ablation. The cryoablation lesions in the left atrium are supposed to disconnect the pulmonary vein from the atrium on the atrial side of the orifices. We hypothesized that the cryoballoon pulmonary vein isolation could result in the prolongation of the P wave duration. The aim of the study was to assess the duration of the P wave in 12-lead electrocardiogram and the influence of pulmonary vein isolation on this parameter. The study group included 21 patients (11 women and 10 men) 66.2+/-7.4 years of age undergoing cryoballoon ablation. In order to measure the P wave duration, we used the constant acquisition of electrogram and the electrocardiographic channels provided by LABSYSTEM™ Pro EP Recording System (Boston Scientific), magnifying the leads 64x. We calculated the duration in the simultaneously recorded 12-lead ECG, from the beginning of the earliest recorded P wave deflection, until the end of the latest P-wave deflection recorded in any lead. The P wave duration in the entire study group was 141.7+/-12.5 ms before the ablation and increased significantly to 151.1+/-11.5 ms (p<0.05) after the procedure. The respective values in women were 144.1+/-4.3 vs. 156.0+/-4.7 ms (p<0.01) and 139.1+/-4.6 vs. 145.6+/-4.5 ms in men (p<0.05). The mean standard deviation of every single measurement considered separately was 4.4+/-2.1 ms before the cryoablation and 4.6+/-1.8 ms after the procedure (p= not significant (n.s).), indicating very good reproducibility of the measurements. We concluded, that cryoballoon pulmonary vein isolation leads to the prolongation of the measured P wave duration. It seemed to result from conduction disturbances created by cryoablation. The clinical significance of the observed changes remains unknown.
Źródło:
European Journal of Translational and Clinical Medicine; 2018, 1, 1; 44-47
2657-3148
2657-3156
Pojawia się w:
European Journal of Translational and Clinical Medicine
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An echocardiographic tool for the interatrial conduction disorders – old dog, new tricks?
Autorzy:
Zawadzki, Jacek M.
Gajek, Jacek J.
Sławuta, Agnieszka
Kozłowski, Dariusz
Zaborniak, Gabriel
Kudliński, Bartosz
Powiązania:
https://bibliotekanauki.pl/articles/24987707.pdf
Data publikacji:
2024-01-08
Wydawca:
Gdański Uniwersytet Medyczny
Tematy:
ECG
P wave
LA strain
echocardiography
Bachmann's bundle
Opis:
Background: Bachmann’s bundle plays a crucial role in the physiology of interatrial signal conduction. In the 1970s, Bayes de Luna introduced the definition of interatrial blocks (IABs), which negatively influence atrioventricular (AV) synchrony and left atrial (LA) activation. We aimed to assess the potential of LA strain technology in evaluating the mechanics of LA in patients with correct conduction and IABs. Additionally, we measured the parameters of regurgitation in pulmonary veins (PV), which depend on the type of interatrial conduction. Material and methods: The study group comprised 51 patients (26M, 25F) with symptomatic COVID-19 and sinus rhythm. Our study analyzed their medical history, electrocardiography (ECG) and echocardiography, including the LA strain parameters. Results: Global peak atrial longitudinal strain (PALS) depended on P wave duration, LA volume, left ventricular ejection fraction (LV EF) and inferior pulmonary veins (PV) regurgitation parameters. Global peak atrial contractile strain (PACS) statistically depends on the LV EF, LA volume and the P wave morphology. Conclusions: The presence of IABs negatively influences PACS and PALS. Examining LA strain is complementary to accurate ECG, which may be helpful in everyday clinical practice, particularly in diagnosing heart failure with preserved ejection fraction (HFpEF) and as a predictor of new episodes of atrial fibrillation (AF).
Źródło:
European Journal of Translational and Clinical Medicine; 2023, 6, 2; 26-35
2657-3148
2657-3156
Pojawia się w:
European Journal of Translational and Clinical Medicine
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of ultrasonic velocity measurement and thermal analysis for determination of limestone quality
Autorzy:
Kilic, O.
Powiązania:
https://bibliotekanauki.pl/articles/110569.pdf
Data publikacji:
2014
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
limestone properties
thermal decomposition
TG-DTA
P-wave velocity
Opis:
Limestone is an important industrial raw material. It is consumed by chemical and other industries (84%), used as refractory and road construction material (12%) and applied in civil engineering and agricultural applications (4%). Substantial amounts of limestone are also used as lime in the iron and steel industry. The aim of this study was to determine the properties of limestones. The chemical, physical and thermal properties of limestones were determined by standard methods while the P-wave velocities of limestones were measured with an ultrasonic non-destructive tester and relationships between limestone properties were estimated. It was found that there is a statistical correlation between physical properties and the P-wave velocity of limestones. The P-wave velocity is a very good characteristic parameter for the study and estimation of the limestone quality.
Źródło:
Physicochemical Problems of Mineral Processing; 2014, 50, 2; 525-534
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Military jet pilots have higher p-wave dispersions compared to the transport aircraft aircrew
Autorzy:
Çakar, Mustafa
Metin, Süleyman
Balta, Şevket
Öztürk, Cengiz
Demirkol, Sait
Çakmak, Tolga
İnal, Satılmış
Çelik, Turgay
İyisoy, Atilla
Ünlü, Murat
Şen, Ahmet
Powiązania:
https://bibliotekanauki.pl/articles/2177416.pdf
Data publikacji:
2016-05-05
Wydawca:
Instytut Medycyny Pracy im. prof. dra Jerzego Nofera w Łodzi
Tematy:
atrial fibrillation
p-wave dispersion
military aircrew
TSH
jet pilots
arrythmia
Opis:
Objectives For the purpose of flight safety military aircrew must be healthy. P-wave dispersion (PWD) is the p-wave length difference in an electrocardiographic (ECG) examination and represents the risk of developing atrial fibrillation. In the study we aimed at investigating PWD in healthy military aircrew who reported for periodical examinations. Material and Methods Seventy-five asymptomatic military aircrew were enrolled in the study. All the subjects underwent physical, radiologic and biochemical examinations, and a 12-lead electrocardiography. P-wave dispersions were calculated. Results The mean age of the study participants was 36.15±8.97 years and the mean p-wave duration was 100.8±12 ms in the whole group. Forty-seven subjects were non-pilot aircrew, and 28 were pilots. Thirteen study subjects were serving in jets, 49 in helicopters, and 13 were transport aircraft pilots. Thirty-six of the helicopter and 11 of the transport aircraft aircrew were non-pilot aircrew. P-wave dispersion was the lowest in the transport aircraft aircrew, and the highest in jet pilots. P-wave dispersions were similar in the pilots and non-pilot aircrew. Twenty-three study subjects were overweight, 19 had thyroiditis, 26 had hepatosteatosis, 4 had hyperbilirubinemia, 2 had hypertension, and 5 had hyperlipidemia. The PWD was significantly associated with thyroid-stimulating hormone (TSH) levels. Serum uric acid levels were associated with p-wave durations. Serum TSH levels were the most important predictor of PWD. Conclusions When TSH levels were associated with PWD, uric acid levels were associated with p-wave duration in the military aircrew. The jet pilots had higher PWDs. These findings reveal that military jet pilots may have a higher risk of developing atrial fibrillation, and PWD should be recorded during periodical examinations.
Źródło:
International Journal of Occupational Medicine and Environmental Health; 2016, 29, 4; 563-572
1232-1087
1896-494X
Pojawia się w:
International Journal of Occupational Medicine and Environmental Health
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Reflection of P-wave and SV-wave in a generalized two temperature thermoelastic half-space
Autorzy:
Santra, S.
Lahiri, A.
Das, N. C.
Powiązania:
https://bibliotekanauki.pl/articles/955250.pdf
Data publikacji:
2014
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
termosprężystość
izoterma
pole termiczne
P-wave
SV-wave
conductive temperature
dynamical temperature
second sound
Opis:
In this work the theory of two temperature generalized thermoelasticity has been used to investigate the problem of reflection of P-wave and SV-wave in a half space when the surface is i) thermally insulated or ii) isothermal. The ratios of the reflection coefficient to that of the incident coefficient for different cases are obtained for P-wave and SV-waves. The results for various cases for the conductive and dynamical temperature have been compared. The results arrived at in the absence of the thermal field (elastic case) have also been compared with those in the existing literature. Finally, the results for various cases have been analyzed and depicted in graphs.
Źródło:
International Journal of Applied Mechanics and Engineering; 2014, 19, 4; 735-754
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
P-wave interaction with a pair of rigid strips embedded in an orthotropic strip
Autorzy:
Basu, S.
Mandal, S. C.
Powiązania:
https://bibliotekanauki.pl/articles/281710.pdf
Data publikacji:
2016
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
P-wave
Fourier transform
Hilbert transform
Fredholm integral equation
stress intensity factor
Opis:
The present paper is concerned with the problem of scattering of the P-wave by two co- -planer finite rigid strips placed symmetrically in an infinitely long orthotropic strip. Using the Hilbert transform technique, the mixed boundary value problem has been reduced to the solution of dual integral equations which has finally been reduced to the solution of a Fredholm integral equation of the second kind. Solving this integral equation numerically, stress intensity factors have been calculated at the inner and outer edges of the rigid strips, and the vertical displacement outside the strips has been calculated and plotted graphically to show the effect of material orthotropy.
Źródło:
Journal of Theoretical and Applied Mechanics; 2016, 54, 2; 579-592
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Sejsmiczna ocena spękania górotworu karbońskiego w rejonach płytkiej działalności górniczej
Seismic evaluation of the Carboniferous rock mass destruction in shallow mining regions
Autorzy:
Dec, J.
Powiązania:
https://bibliotekanauki.pl/articles/183648.pdf
Data publikacji:
2009
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
spękania
prędkość fali P
jakość masywu skalnego
cracks density
P-wave velocity
rock quality designation
Opis:
Results of seismic investigations are presented in this paper. Investigation were carried out in regions of shallow coal exploitation. In those regions we can observe strongly disturbed zones. In such case seismic measurements show the strong velocity anomalies. Velocity of seismic P wave strongly depends on the cracks density. As a results of investigation a relationship between RQD (Rock Quality Designation), cracks density and P wave velocity is shown. Quality index QI is the best estimator of the real Carboniferous rock mass destruction. As a final result the seismic scale of the Carboniferous rocks evaluation is proposed.
Źródło:
Geologia / Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie; 2009, 35, 2/1; 405-412
0138-0974
Pojawia się w:
Geologia / Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Multi-method approach to velocity determination from acoustic well logging
Autorzy:
Jarzyna, J.
Bała, M.
Krakowska, P.
Powiązania:
https://bibliotekanauki.pl/articles/191745.pdf
Data publikacji:
2013
Wydawca:
Polskie Towarzystwo Geologiczne
Tematy:
P-wave slowness
S-wave slowness
acoustic full waveforms
FalaFWS application
Estymacja program
acoustic wave frequency
seismic wave frequency
Opis:
Three different methods of building detailed velocity models for seismic interpretation are explained and discussed in terms of their advantages and limitations. All of the proposed methods are based on the analysis of acoustic well logs. An application of acoustic full waveform measurements, as well as the FalaFWS and Estymacja software, is presented as a tool for determining P-wave and S-wave slowness (transit time interval, velocity reciprocal). Well log data from several wells, located near the special research seismic transect in the Polish Lowland, were processed using the methods proposed. The results of data analysis are presented for a depth section of up to 3623 m for the lithostratigraphic units, recorded from the Środa Wielkopolska 5 (SW5) well. The results of P-wave and S-wave slowness filtering, used to upscale well log data to a seismic scale of resolution, are shown for the entire geological profile of the SW5 well.
Źródło:
Annales Societatis Geologorum Poloniae; 2013, 83, 2; 133--147
0208-9068
Pojawia się w:
Annales Societatis Geologorum Poloniae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparison of seismic sources for shallow seismic: sledgehammer and pyrotechnics
Autorzy:
Brom, A.
Stan-Kłeczek, I.
Powiązania:
https://bibliotekanauki.pl/articles/100856.pdf
Data publikacji:
2015
Wydawca:
Uniwersytet Śląski. Wydział Nauk o Ziemi
Tematy:
pyrotechnic material
seismic refraction method
P-wave velocity
materiał pirotechniczny
metoda
refrakcja
prędkość
Opis:
The pyrotechnic materials are one of the types of the explosives materials which produce thermal, luminous or sound effects, gas, smoke and their combination as a result of a self-sustaining chemical reaction. Therefore, pyrotechnics can be used as a seismic source that is designed to release accumulated energy in a form of seismic wave recorded by tremor sensors (geophones) after its passage through the rock mass. The aim of this paper was to determine the utility of pyrotechnics for shallow seismic engineering. The work presented comparing the conventional method of seismic wave excitation for seismic refraction method like plate and hammer and activating of firecrackers on the surface. The energy released by various sources and frequency spectra was compared for the two types of sources. The obtained results did not determine which sources gave the better results but showed very interesting aspects of using pyrotechnics in seismic measurements for example the use of pyrotechnic materials in MASW.
Źródło:
Contemporary Trends in Geoscience; 2015, 4, 1; 39-45
2299-8179
Pojawia się w:
Contemporary Trends in Geoscience
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The influence of pore media distribution on the elastic parameters of rocks in Miocene sediments (Carpathian Foredeep, Poland, B deposit)
Autorzy:
Bała, M.
Powiązania:
https://bibliotekanauki.pl/articles/184347.pdf
Data publikacji:
2015
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
P-wave velocity
S-wave velocity
theoretical Kuster– Toksöz model
Biot-Gassmann model
water saturation
gas saturation
porosity
Opis:
This paper presents the results of modelling compressional and shear wave velocities and elastic moduli, as well as Poisson’s coefficient changes in sandstone-shale rocks, based on the distribution of media reservoir (water, gas) in the pore space. Modelling was performed using the Estymacja-TP computer program and theoretical Kuster–Toksöz and Biot–Gassmann relationships. Phase distribution of saturating pores (ellipsoidal shapes) in several ways was assumed. Calculations were made of elastic parameters in the deposits of the autochthonous Miocene Sarmatian in the borehole B-4. Using a method similar to the so-called “fluid substitution” velocity of compressional and shear waves, elastic moduli, Poisson’s ratio and bulk density, under various conditions of water and gas saturation, were calculated. The assumed change in water saturation ranged from Sw = 0% to 100%.
Źródło:
Geology, Geophysics and Environment; 2015, 41, 2; 155-167
2299-8004
2353-0790
Pojawia się w:
Geology, Geophysics and Environment
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wyniki badań testu wytrzymałościowego próbki węgla w świetle badań tomograficznych
Research results of triaxial geomechanical tests of a coal sample in the light of tomographic tests
Autorzy:
Dohnalik, Marek
Krakowska-Madejska, Paulina
Puskarczyk, Edyta
Jelonek, Iwona
Powiązania:
https://bibliotekanauki.pl/articles/2146244.pdf
Data publikacji:
2021
Wydawca:
Instytut Nafty i Gazu - Państwowy Instytut Badawczy
Tematy:
rentgenowska tomografia komputerowa
analiza obrazu
test wytrzymałościowy
prędkość fal P i S
computed tomography
image analysis
geomechanical test
P-wave and S-wave velocity
Opis:
Celem niniejszej pracy było sprawdzenie możliwości wykorzystania rentgenowskiej tomografii komputerowej (CT) do obserwacji spękań w badanej próbce węgla przed i po teście geomechanicznym, przeprowadzonym w stanie trójosiowych naprężeń (TRX). W pracy przedstawiono zastosowanie dwóch specjalistycznych technik laboratoryjnych: rentgenowskiej tomografii komputerowej i geomechanicznego trójosiowego testu ściskania. Testy geomechaniczne przeprowadzono za pomocą zestawu pomiarowego TRX-070, GCTS (USA), rejestrując pełną charakterystykę naprężeniowo-odkształceniową. Podczas trójosiowych testów ściskania wykonano też innowacyjne równoczesne pomiary prędkości fal P i S. Próbkę analizowano w dwóch etapach, zdefiniowanych ze względu na stan próbki w obrazie CT: pomiar CT wykonany na nienaruszonej próbce węgla (etap 1) oraz otrzymany po teście zniszczeniowym (etap 2). W pierwszym etapie próbka została zeskanowana w celu odzwierciedlenia początkowego stanu struktury porowej wraz z układem mikropęknięć. Drugi etap reprezentuje próbkę po badaniu geomechanicznym. Dla każdego z etapów przeprowadzono szczegółową analizę struktury porowej. W wyniku proponowanego połączenia wymienionych metod w każdym etapie uzyskano obrazy struktury porów. Próbkę analizowano pod kątem liczby i kierunków propagacji pęknięć i zmian w strukturze porów. Interpretacja jakościowa i ilościowa opierała się na rejestracji zmiany liczby pustek, średnic pęknięć, kątów zapadania i porównaniu struktury porowej pomiędzy stanem początkowym próbki oraz po badaniu geomechanicznym. W 1 etapie (przed testem) największy obiekt (zidentyfikowany jako mikroszczelina) przyjmował objętość powyżej 16 mm3 , po wystawieniu próbki na działanie naprężeń (po zniszczeniu próbki) największy zidentyfikowany obiekt charakteryzował się objętością około 15 razy większą (240 mm3 ). Zidentyfikowane w etapie 2 (po teście wytrzymałościowym) pory są wydłużone (wysokie wartości parametru Elongation), a także nie wykazują znaczącego spłaszczenia (Flatness). Według uzyskanych wyników próbka węgla była podatna na pękanie w określonych kierunkach. Kompleksowe badania wykazały zasadność zastosowania proponowanej metodologii do oceny zmian w strukturze próbki podczas testu wytrzymałościowego.
The study aimed to check the possibility of using computed tomography to observe fractures in coal samples before and after a triaxial compression test (TRX). The paper presents an innovative use of two specialized laboratory techniques: computed tomography and geomechanical triaxial compression test. Geomechanical tests were performed on a TRX-070, GCTS (USA) measuring triaxial system. A full stress-strain characteristic was recorded. Also, during the triaxial compression tests, the P and S wave velocities were measured and dynamic elastic moduli were determined. The results were compared. The sample was analyzed in two stages: CT measurement performed on raw coal sample (stage 1) and after the TRX test which destroyed the sample structure (stage 2). First, the sample was scanned reflecting the initial pores and microcracks system. The final stage represents the sample after the geomechanical test. A detailed pore structure analysis was performed for each of the stages. As a result of the proposed above-mentioned method, images of the pore structure were obtained after each step. The sample was analyzed for crack propagation and changes in the pore structure. The qualitative and quantitative interpretation was based on the determination of the number of voids, crack diameters, collapse angles, and comparison of the pore structure between the initial state of the sample and after the triaxial test. In the first stage (before the test), the largest object (identified as a microcrack) had a volume of approximately 16 mm3 , after the sample was stress-tested (after the sample was destroyed), the largest identified object was about 15 times larger (240 mm3 ). It appeared that the coal sample was prone to fracturing in defined directions. Comprehensive research has demonstrated the legitimacy of using the proposed methodology to evaluate changes in the sample structure during the triaxial test.
Źródło:
Nafta-Gaz; 2021, 77, 1; 3-9
0867-8871
Pojawia się w:
Nafta-Gaz
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Seismic velocity of P-waves to evaluate strength of stabilized soil for Svenska Cellulosa Aktiebolaget Biorefinery Östrand AB, Timrå
Autorzy:
Lindh, Per
Lemenkova, Polina
Powiązania:
https://bibliotekanauki.pl/articles/2173666.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
unconfined compressive strength
P-wave velocity
stabilized soil
cement
slag
nieograniczona wytrzymałość na ściskanie
prędkość fali P
gleba stabilizowana
żużel
Opis:
Evaluating soil strength by geophysical methods using P-waves was undertaken in this study to assess the effects of changed binder ratios on stabilization and compression characteristics. The materials included dredged sediments collected in the seabed of Timrå region, north Sweden. The Portland cement (Basement CEM II/A-V, SS EN 197-1) and ground granulated blast furnace slag (GGBFS) were used as stabilizers. The experiments were performed on behalf of the Svenska Cellulosa Aktiebolaget (SCA) Biorefinery Östrand AB pulp mill. Quantity of binder included 150, 120 and 100 kg. The properties of soil were evaluated after 28, 42, 43, 70, 71 and 85 days of curing using applied geophysical methods of measuring the travel time of primary wave propagation. The P-waves were determined to evaluate the strength of stabilized soils. The results demonstrated variation of P-waves velocity depending on stabilizing agent and curing time in various ratios: Low water/High binder (LW/HB), High water/Low binder (HW/LB) and percentage of agents (CEM II/A-V/GGBFS) as 30%/70%, 50%/50% and 70%/30%. The compression characteristics of soils were assessed using uniaxial compressive strength (UCS). The P-wave velocities were higher for samples stabilized with LW/HB compared to those with HW/LB. The primary wave propagation increased over curing time for all stabilized mixes along with the increased UCS, which proves a tight correlation with the increased strength of soil solidified by the agents. Increased water ratio gives a lower strength by maintained amount of binder and vice versa.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2022, 70, 4; art. no. e141593
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dynamic elastic properties of the hard coal seam at a depth of around 1260 m
Dynamiczne sprężyste właściwości pokładu węgla na głębokości około 1260 m
Autorzy:
Krawiec, Krzysztof
Powiązania:
https://bibliotekanauki.pl/articles/1849546.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Instytut Gospodarki Surowcami Mineralnymi i Energią PAN
Tematy:
dynamic elastic parameters
coal seam
P-wave velocity
S-wave velocity
seismic profiling
dynamiczne parametry sprężyste
pokład węgla
prędkość fali P
prędkość fali S
profilowanie sejsmiczne
Opis:
The knowledge of the dynamic elastic properties of a coal seam is important in the context of various types of calculations of the seam behavior under various stress-strain conditions. These properties are often used in numerical and analytical modeling related to maintaining the stability of excavations and the analysis of mechanisms, e.g. related to the risk of rock bursts. Additionally, during the implementation of seismic surveys, e.g. seismic profiling and seismic tomography in coal seams, the reference values of the elastic properties of coal are used in the calculation of relative stresses in various geological and mining conditions. The study aims to calculate the dynamic elastic parameters of the coal seam located at a depth of 1,260 m in one of the hard coal mines in the Upper Silesian Coal Basin (USCB). Basic measurements of the velocity of P- and S-waves were conducted using the seismic profiling method. These surveys are unique due to the lack of the velocity wave values in the coal seam at such a great depth in the USBC and difficult measurement conditions in a coal mine. As a result, dynamic modulus of elasticity was calculated, such as Young’s modulus, volumetric strain modulus, shear modulus and Poisson’s ratio. The volumetric density of coal used for calculations was determined on the basis of laboratory tests on samples taken in the area of the study. The research results showed that the calculated mean P-wave velocity of 2,356 m/s for the depth of 1,260 m is approximately consistent with the empirical relationship obtained by an earlier study. The P-wave velocity can be taken as the reference velocity at a depth of approx. 1,260 m in the calculation of the seismic anomaly in the seismic profiling method.
Znajomość dynamicznych właściwości sprężystych pokładu węgla jest istotna w kontekście różnego rodzaju obliczeń zachowania się pokładu w różnorakich warunkach naprężeniowo-odkształceniowych. Właściwości te są często wykorzystywane w modelowaniach numerycznych i analitycznych związanych z utrzymaniem stateczności wyrobisk oraz analizą mechanizmów, np. związanych z zagrożeniem tąpaniami. Dodatkowo w trakcie realizacji badań sejsmicznych np. profilowań sejsmicznych i tomografii sejsmicznej w pokładach węgla referencyjne wartości właściwości sprężyste węgla wykorzystywane są w obliczaniach naprężeń względnych w różnych warunkach geologiczno-górniczych. Celem badań jest obliczenie dynamicznych sprężystych parametrów pokładu węgla, położonego na głębokości około 1260 m, w jednej z kopalń węgla kamiennego w Górnośląskim Zagłębiu Węglowym. Podstawowe pomiary prędkości fal sejsmicznych wykonano metodą profilowania sejsmicznego. Te pomiary są unikatowe ze względu na dużą głębokość położenia profilu pomiarowego oraz trudne warunki pomiarowe w kopalni. W efekcie obliczono dynamiczne moduły sprężystości takie jak: moduł Younga, moduł odkształcenia objętościowego, moduł odkształcenia postaciowego oraz współczynnik Poissona. Gęstość objętościową węgla przyjętą do obliczeń wyznaczono na podstawie testów laboratoryjnych na próbach pobranych w rejonie badań. Wyniki badań pokazały, że obliczona średnia prędkość fali P równa 2356 m/s dla głębokości 1260 m jest w przybliżeniu zgodna z empirycznymi zależnościami określonymi we wcześniejszych badaniach. Prędkość fali P może być przyjęta jako prędkość odniesienia na głębokości około 1260 m w obliczeniach anomalii sejsmicznej w metodzie profilowania sejsmicznego.
Źródło:
Gospodarka Surowcami Mineralnymi; 2021, 37, 3; 159-176
0860-0953
Pojawia się w:
Gospodarka Surowcami Mineralnymi
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wpływ obecności iłów, porowatości oraz nasycenia porów wodą i gazem na parametry sprężyste skał zbiornikowych określanych na podstawie teoretycznych modeli ośrodków porowatych i danych geofizyki wiertniczej
Effects of shale content, porosity and water- and gas-saturation in pores on elastic parameters of reservoir rocks based on theoretical models of porous media and well-logging data
Autorzy:
Bała, M.
Powiązania:
https://bibliotekanauki.pl/articles/2074505.pdf
Data publikacji:
2007
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
nasycenie wodą
nasycenie gazem
prędkość fali P
prędkość fali S
współczynnik Poissona
skały zbiornikowe
P-wave velocity
S-wave velocity
elastic modulus
Poisson ratio
shale content
water saturation
gas saturation
Opis:
The paper describes effects of shale content, porosity and water- and gas saturation on elastic parameters of rocks. The analysis was based on theoretical relationships for porous media, known as the Biot-Gassmann's and Kuster and Toksöz's models, and on Raymer-Hunt-Gardner formulas. Well-logging data and results of the quantitative interpretation of well logs were also analysed. The relationships between P-wave and S-wave velocities and reservoir parameters may contribute to solving some problems associated with seismic interpretation of wave forms in Miocene gas deposits in the Carpathian Foredeep.
Źródło:
Przegląd Geologiczny; 2007, 55, 1; 46-53
0033-2151
Pojawia się w:
Przegląd Geologiczny
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 18

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