scholarly journals Validity of a theoretical model to examine blood oxygenation dependent optoacoustics

2021 ◽  
Author(s):  
Michael C. Kolios ◽  
Ratan K. Saha ◽  
Subhajit Karmakar ◽  
Eno Hysi ◽  
Madhusudan Roy
Keyword(s):  
Theoretical Model ◽  
Power Spectra ◽  
Signal Amplitude ◽  
Blood Oxygenation ◽  
Frequency Range ◽  
Entire Frequency Range ◽  
Blood Oxygen Saturation ◽  
A Cell ◽  
Laser Sources ◽  
Good Agreement

A theoretical model investigating the dependence of optoacoustic (OA) signal on blood oxygen saturation (SO2) is discussed. The derivations for the nonbandlimited and bandlimited OA signals from many red blood cells (RBCs) are presented. The OA field generated by many RBCs was obtained by summing the OA field emitted by each RBC approximated as a fluid sphere. A Monte Carlo technique was employed generating the spatial organizations of RBCs in two-dimensional. The RBCs were assumed to have the same SO2 level in a simulated configuration. The fractional number of oxyhemoglobin molecules, confined in a cell, determined the cellular SO2 and also defined the blood SO2. For the nonbandlimited case, the OA signal amplitude decreased and increased linearly with blood SO2 when illuminated by 700 and 1000 nm radiations, respectively. The power spectra exhibited similar trends over the entire frequency range (MHz to GHz). For the bandlimited case, three acoustic receivers with 2, 10, and 50 MHz as the center frequencies were considered. The linear variations of the OA amplitude with blood SO2 were also observed for each receiver at those laser sources. The good agreement between simulated and published experimental results validates the model qualitatively.

scholarly journals Validity of a theoretical model to examine blood oxygenation dependent optoacoustics

2021 ◽  
Author(s):  
Michael C. Kolios
Keyword(s):  
Theoretical Model ◽  
Power Spectra ◽  
Signal Amplitude ◽  
Blood Oxygenation ◽  
Frequency Range ◽  
Entire Frequency Range ◽  
Blood Oxygen Saturation ◽  
A Cell ◽  
Laser Sources ◽  
Good Agreement

A theoretical model investigating the dependence of optoacoustic (OA) signal on blood oxygen saturation (SO2) is discussed. The derivations for the nonbandlimited and bandlimited OA signals from many red blood cells (RBCs) are presented. The OA field generated by many RBCs was obtained by summing the OA field emitted by each RBC approximated as a fluid sphere. A Monte Carlo technique was employed generating the spatial organizations of RBCs in two-dimensional. The RBCs were assumed to have the same SO2 level in a simulated configuration. The fractional number of oxyhemoglobin molecules, confined in a cell, determined the cellular SO2 and also defined the blood SO2. For the nonbandlimited case, the OA signal amplitude decreased and increased linearly with blood SO2 when illuminated by 700 and 1000 nm radiations, respectively. The power spectra exhibited similar trends over the entire frequency range (MHz to GHz). For the bandlimited case, three acoustic receivers with 2, 10, and 50 MHz as the center frequencies were considered. The linear variations of the OA amplitude with blood SO2 were also observed for each receiver at those laser sources. The good agreement between simulated and published experimental results validates the model qualitatively.

scholarly journals Validity of a theoretical model to examine blood oxygenation dependent optoacoustics

2021 ◽  
Author(s):  
Michael C. Kolios
Keyword(s):  
Theoretical Model ◽  
Power Spectra ◽  
Signal Amplitude ◽  
Blood Oxygenation ◽  
Frequency Range ◽  
Entire Frequency Range ◽  
Blood Oxygen Saturation ◽  
A Cell ◽  
Laser Sources ◽  
Good Agreement

A theoretical model investigating the dependence of optoacoustic (OA) signal on blood oxygen saturation (SO2) is discussed. The derivations for the nonbandlimited and bandlimited OA signals from many red blood cells (RBCs) are presented. The OA field generated by many RBCs was obtained by summing the OA field emitted by each RBC approximated as a fluid sphere. A Monte Carlo technique was employed generating the spatial organizations of RBCs in two-dimensional. The RBCs were assumed to have the same SO2 level in a simulated configuration. The fractional number of oxyhemoglobin molecules, confined in a cell, determined the cellular SO2 and also defined the blood SO2. For the nonbandlimited case, the OA signal amplitude decreased and increased linearly with blood SO2 when illuminated by 700 and 1000 nm radiations, respectively. The power spectra exhibited similar trends over the entire frequency range (MHz to GHz). For the bandlimited case, three acoustic receivers with 2, 10, and 50 MHz as the center frequencies were considered. The linear variations of the OA amplitude with blood SO2 were also observed for each receiver at those laser sources. The good agreement between simulated and published experimental results validates the model qualitatively.

Elliptical Annular Slot Loaded Trapezoidal Dipole Antenna for Band-Notched UWB Applications

2016 ◽  
Vol 12 (1) ◽  
pp. 23-29
Author(s):  
Sarthak Singhal ◽  
Nand Verma ◽  
Amit Singh
Keyword(s):  
Impedance Matching ◽  
Dipole Antenna ◽  
Frequency Range ◽  
Entire Frequency Range ◽  
Antenna Structure ◽  
Annular Slot ◽  
Notched Band ◽  
Uwb Applications ◽  
Peak Gain ◽  
Good Agreement

In this paper, a semi-elliptical annular slot loaded trapezoidal dipole antenna with band-notched characteristics for UWB applications is designed. A microstrip feedline consisting of multiple feedline sections is used for improving the impedance matching. The band-notched characteristics for WLAN band are achieved by loading the trapezoidal dipole arms with semi-elliptical annular slots. The designed antenna structure has an operating range from 3.5-12.4 GHz(109%) with band-rejection in the frequency range of 5-6 GHz. Nearly omnidirectional patterns are achieved for the designed antenna structure. The designed antenna structure provided an average peak gain of 2.12 dB over the entire frequency range except in the notched band where it reduced to -2.4 dB. The experimental and simulation results are observed to be in good agreement. An improved bandwidth performance with miniaturized dimensions as compared to earlier reported antenna structures is achieved.

An Experimental Study on the Damping of a Steam Generator Tube With Gap Supports in Air and Water

2016 ◽  
Author(s):  
Heung Seok Kang ◽  
Kang Hee Lee ◽  
Chang Whan Shin ◽  
Chang Hoon Ha ◽  
Tae Jeung Park
Keyword(s):  
Theoretical Model ◽  
Steam Generator ◽  
Low Frequency ◽  
Empirical Correlation ◽  
Frequency Range ◽  
Fluid Damping ◽  
Practical Model ◽  
Inactive Mode ◽  
Plate Type ◽  
Good Agreement

In this study, we present an analysis and experiment on the fluid damping of a Steam Generator (SG) tube with one and several plate-type supports that are submerged under water. For the damping measurement, a short tube of 2.2 meters in length with one gap support as well as a long tube of up to 10 meters with 11 and 13 supports are used. To see a fluid effect through an analytical approach, Mulcahy’s theory on a tube with finite-length gap support and Pettigrew’s empirical correlation for SG design were reviewed. The theoretical model is good at predicting the fluid damping at the first mode in a low frequency range which is an inactive mode at the support, while the practical model is much better at the higher modes, which are active modes, rocking modes, at the support(s). Experimental results from the short length tube with single support shows good agreement with a previous measurement by other researchers. A theoretical model and empirical correlation are in good agreement. Our measurements from a longer tube with several supports are reasonable compared with the others. There is, however, a wide discrepancy between predictions by the two models. As compared with the whole measurements, the theoretical model seems to be a good guideline in a low frequency range, while an empirical model is relatively good guideline in a high frequency range. Based on the whole collected data, a new correlation modified from Pettigrew’s correlation is suggested.

scholarly journals A compact slot antenna with improved bandwidth and gain for wireless applications

2018 ◽  
Vol 7 (4) ◽  
pp. 2370
Author(s):  
Aadya Pant ◽  
Swapna Ch ◽  
Manish Bharat
Keyword(s):  
Ground Plane ◽  
Dielectric Substrate ◽  
Slot Antenna ◽  
Frequency Range ◽  
Entire Frequency Range ◽  
Rectangular Slot ◽  
Wireless Applications ◽  
Feed Line ◽  
Bottom Side ◽  
Good Agreement

A wide-slot antenna is investigated to achieve a bandwidth of about 162%. The ground plane includes a rectangular slot with dual SRR and two semicircular defects in the bottom side of the rectangular slot. A fork like feed-line with two parasitic stubs to increase the bandwidth is used to feed the slot. 37*37*0.8 mm3 is the size of the proposed antenna and the dielectric substrate used is FR4. The measured bandwidth ranges from 1.8-17.5 GHz which is approximately 162%. Significant improvement in gain for the frequency range of 1.8-6.1 GHz is observed. The proposed antenna has radiation patterns that are stable and omnidirectional in both E and H planes in all the six frequency points for entire frequency range. The simulated and measured results are in good agreement.  

scholarly journals Акустические колебания алюминиевых мембран при лазерном возбуждении по термоупругому механизму

2020 ◽  
Vol 46 (10) ◽  
pp. 18
Author(s):  
А.Л. Глазов ◽  
К.Л. Муратиков
Keyword(s):  
Laser Radiation ◽  
Theoretical Model ◽  
Photoacoustic Signal ◽  
Frequency Range ◽  
Surface Absorption ◽  
Membrane Vibrations ◽  
Theoretical Results ◽  
Good Agreement

A theoretical model of the formation of a photoacoustic signal from metal membranes by laser radiation is proposed taking into account the excitation of defective states in them. The theoretical results obtained are compared for aluminum membranes with a thickness of 197 μm in the frequency range from 20 Hz to 7 kHz when they are excited by laser radiation with a wavelength of 660 nm. It is shown that the proposed theoretical model ensures good agreement between the experimental and theoretical results for membrane vibrations with a purely surface absorption of laser radiation.

The working standard of the unit of power of electromagnetic waves in the frequency range from 37,5 to 220 GHz

2020 ◽  
pp. 53-58
Author(s):  
A. V. Koudelny ◽  
I. M. Malay ◽  
V. A. Perepelkin ◽  
I. P. Chirkov
Keyword(s):  
Microwave Power ◽  
Electromagnetic Waves ◽  
Primary Standard ◽  
The State ◽  
Frequency Range ◽  
Working Standard ◽  
Extended Frequency Range ◽  
Effective Efficiency ◽  
Extended Frequency ◽  
Good Agreement

The possibility of using bolometric converters of microwave power from the State primary standard of the unit of power of electromagnetic waves in waveguide and coaxial paths GET 167-2017, which has a frequency range from 37,5 to 78,33 GHz, in an extended frequency range up to 220 GHz, is shown. Studies of semiconductor bolometric converters of microwave power in an extended frequency range have confirmed good agreement and smooth frequency characteristics of the effective efficiency factor of the converters. Based on the research results, the State working standard of the unit of power of electromagnetic waves of 0,1–10 mW in the frequency range from 37,5 to 220 GHz 3.1.ZZT.0288.2018 was approved. The technical characteristics of the working standard of the unit of power of electromagnetic oscillations in an extended frequency range from 37,5 to 220 GHz are given.

scholarly journals Observation evidences of atmospheric Gravity Waves induced by seismic activity from analysis of subionospheric LF signal spectra

2007 ◽  
Vol 7 (5) ◽  
pp. 625-628 ◽  
Author(s):  
A. Rozhnoi ◽  
M. Solovieva ◽  
O. Molchanov ◽  
P.-F. Biagi ◽  
M. Hayakawa
Keyword(s):  
Gravity Waves ◽  
Fresnel Zone ◽  
Signal Amplitude ◽  
Magnetic Storms ◽  
Frequency Range ◽  
Atmospheric Gravity Waves ◽  
Period Range ◽  
Before And After ◽  
Atmospheric Gravity ◽  
Large Earthquakes

Abstract. We analyze variations of the LF subionospheric signal amplitude and phase from JJY transmitter in Japan (F=40 kHz) received in Petropavlovsk-Kamchatsky station during seismically quiet and active periods including also periods of magnetic storms. After 20 s averaging, the frequency range of the analysis is 0.28–15 mHz that corresponds to the period range from 1 to 60 min. Changes in spectra of the LF signal perturbations are found several days before and after three large earthquakes, which happened in November 2004 (M=7.1), August 2005 (M=7.2) and November 2006 (M=8.2) inside the Fresnel zone of the Japan-Kamchatka wavepath. Comparing the perturbed and background spectra we have found the evident increase in spectral range 10–25 min that is in the compliance with theoretical estimations on lithosphere-ionosphere coupling by the Atmospheric Gravity Waves (T>6 min). Similar changes are not found for the periods of magnetic storms.

Damping and Inertia Coefficients for a Rolling or Swaying Vertical Strip

1963 ◽  
Vol 7 (04) ◽  
pp. 19-23
Author(s):  
J. Kotik
Keyword(s):  
Wave Amplitude ◽  
Added Mass ◽  
Frequency Range ◽  
Entire Frequency Range ◽  
Vertical Strip ◽  
Amplitude Coefficient

Ursell's exact expression3 for the wave-amplitude coefficient for a swaying or rolling vertical strip is evaluated numerically over the entire frequency range. The added-mass and inertia coefficients are then obtained numerically, also over the entire frequency range, via the Kramers-Kronig relations.

Optical Vibration and Acceleration Sensor With a Silicon Cantilever

1999 ◽  
Author(s):  
Mitsuteru Kimura ◽  
Katsuhisa Toshima ◽  
Harunobu Satoh
Keyword(s):  
Simple Model ◽  
Optical Fiber ◽  
Resonance Frequency ◽  
Acceleration Sensor ◽  
Frequency Range ◽  
Silicon Cantilever ◽  
All Optical ◽  
New Type ◽  
Good Agreement ◽  
Optical Vibration

Abstract A new type all optical vibration and acceleration sensor using the combination of micromachined Si cantilever and optical fiber is proposed, and its fundamental characteristics are demonstrated. The light emitted from bulb-lens set into the V-groove is reflected at the reflector formed on the Si cantilever and then recoupled into the bulb-lens. Several sensors with different length (0.64–6.0 mm long) of the Si cantilever are fabricated to compare the theoretical resonance frequency fr obtained from the simple model and experimental ones. They had good agreement. From the sensing principle the sensing frequency range of the vibration is suitable below the fr of the Si cantilever of the sensor.

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