Acoustic Impedance Research Articles

3D printed high–strength polyimide aerogel metamaterials for sound absorption and thermal insulation

The structural manufacturing of high–performance polyimide (PI) aerogels is challenging because of the insufficient mechanical strength and rheological properties of sol–gel ink, and PI aerogels have limited application. In this study, a PI aerogel–based Helmholtz resonator (PIHM) and its acoustic metamaterial were innovatively constructed using freeze casting–assisted extrusion printing process and building block–assembly strategy, featuring a micro–perforated panel (MPP) sound–absorbing structure. The PIHM with a density of 0.294g·cm−3 achieved a compressive strength of 10.2MPa because of its periodically distributed honeycomb topology. Moreover, the PIHM not only retained the lightweight and thermal insulation characteristics of aerogels but also exhibited excellent sound–absorption performance because of the dual dissipation of sound waves by the MPP structure and PI aerogel framework. By serially connecting PIHMs with different aerogel pore sizes and leveraging the distinct acoustic properties of the layered structure along with the significant increase in relative mass resistance and acoustic impedance, the acoustic metamaterial achieved absorption coefficient peaks of 0.82–0.91 at 622–726Hz, considerably widening the bandwidth with an absorption coefficient greater than 0.8. Finally, the composite sound–absorbing panel fabricated from a PIHM combined with common building materials demonstrated strong practicability and versatility. This research has pioneered a viable method for manufacturing PI aerogels with functional structures through 3D printing, expanding their application in the field of sound absorption and thermal insulation, and paving the way for the study of aerogel metamaterials in construction.

Modeling Thermal Impedance of IGBT Devices Based on Fractional Calculus Techniques

The thermal impedance characteristics of insulated gate bipolar transistor (IGBT) modules are critical for the thermal management and design of electronic devices. This paper proposes a fractional-order equivalent thermal impedance model, which is inspired by the correlation between multi-time-scale dissipation characteristics of heat conduction processes and fractional calculus. The fractional-order equivalent thermal impedance model is derived based on the connection between fractional-order calculus and the Foster thermal network model in mathematical operations, with only two parameters to be identified: heat capacity C and fractional order α. Moreover, this paper provides a parameter identification method for the proposed fractional-order equivalent thermal impedance model based on the multi-objective particle swarm optimization (MOPSO) algorithm. In order to validate the effectiveness and superiority of this work, experiments and comparative works are provided in this paper. The results indicate that the fractional-order equivalent thermal impedance model can accurately describe the frequency domain characteristic curves of the thermal impedance of the Foster thermal network model for IGBT modules, with the difference between the amplitude frequency characteristics not exceeding 1 dB and the difference between the phase frequency characteristics not exceeding 1° within the operating frequency range of (1 kHz, 1 MHz).

Fabrication of Radial Array Transducers Using 1-3 Composite via a Bending and Superposition Technique

Piezoelectric composite materials, combining the advantages of both piezoelectric materials and polymers, have been extensively used in ultrasonic transducers. However, the pitch size of radial array ultrasonic transducers normally exceeds one wavelength, which limits their performance. In order to minimize grating lobes of current radial transducers and then increase their imaging resolution, a 2.5 MHz 1-3 composite radial array transducer with 64 elements and 600 μm pitch was designed and fabricated by combining flexible circuit board and using a bending-and-superposition method. All the array elements were connected and actuated via the customized circuit board which is thin and soft. The kerf size is set to be 1/3 wavelength. PZT-5H/epoxy 1-3 composite was used as an active material because it exhibits an ultrahigh electromechanical coupling coefficient (kt = 0.74), a very low mechanical quality factor (Qm = 11), and relatively low acoustic impedance (Zc = 13.43 MRayls). The developed radial array transducer exhibited a center frequency of 2.72 MHz, an average −6 dB bandwidth of 36%, an insertion loss of 31.86 dB, and a crosstalk of −26.56 dB between the adjacent elements near the center frequency. These results indicate that the bending-and-superposition method is an effective way to fabricate radial array transducers by binding flexible circuit boards. Furthermore, the utilization of tailored flexible circuitry boards presents an effective approach for realizing reductions in crosstalk level (CTL).

Quantitative Assessment of the Effect of Instability Levels on Reactive Human Postural Control Using Different Sensory Organization Strategies

Reactive postural control (RPC), essential for maintaining balance during daily activities, relies on a complex sensory system integrating visual, vestibular, and proprioceptive inputs. Deficits in RPC can lead to falls, especially in unpredictable environments where sensory inputs are challenged. Traditional rehabilitation often fails to prepare patients adequately for real-world conditions. This study aims to explore the effects of varying instability levels (ILs) and sensory integration strategies (SIS) on RPC by evaluating balance disturbances without applying additional external force. Twenty-five healthy participants (12 men, 13 women, 24.5 ± 6.1 years) performed balance tasks on Abili® platforms with adjustable ILs (0, 1, 2, 3) while altering sensory strategies (Basic, Visual, Proprioception, Vestibular) using the Modified Clinical Test of Sensory Integration and Balance (mCTSIB). RPC efficiency was measured using the 95th percentile confidence interval for chest movement’s ellipsoid volume and average velocity, analyzed with Wilcoxon signed-rank tests and Cliff’s delta effect size. Results showed significant increases in chest movement velocity and volume, particularly with the Vestibular strategy at higher ILs, with a 7176% increase in chest volume from Basic strategy at 0IL to Vestibular strategy at 3IL. Additionally, removing visual input (Visual and Vestibular strategies) had a greater impact on chest movement than increasing instability levels. These findings underscore the significant role of combined platform instability and reduced sensory input on postural control. This study presents a novel method for challenging balance and suggests that sensory integration with variable instability could be valuable in training and rehabilitation, even for healthy individuals.

Integrated fracture analysis for improved oil recovery in the reefal limestones of Soğucak formation, Northwest Thrace Basin, Türkiye

Natural fractures play a crucial role in both exploration and development phases in oil and gas industry, as their network and orientation significantly affect flow and recovery strategies. This study highlights the importance of identifying opening-mode fracture systems within a mature Deveçatağı oil field that has been actively producing for nearly half a century. In order to investigate the most effective rock physics parameter to locate oil saturated zones in the field, this study applies detailed rock physics analysis and 2D forward modeling to pinpoint the principal factors affecting production in the Deveçatağı oil field, addressing the challenge posed by the limited shear wave wireline data acquired from only one well within this highly heterogeneous area. Analysis show that acoustic impedance is a crucial elastic property for detecting oil-saturated zones especially in areas with natural fractures. This study successfully integrates drilling-induced fracture (DIF) data, ant tracking maps, and seismic inversion outputs to understand on the issues leading to dry wells and advances in developing more effective exploration and recovery methods in fractured reservoirs. After almost 50 years of operational activities, well stimulation processes, and natural fractures that are present in this field, understanding oil drainage mechanisms in such environments is complex, emphasizing the need for comprehensive analysis to optimize production strategies.

High-resolution acoustic-impedance inversion based on a deep-learning-aided representation model of nonstationary seismic data

Building a high-resolution acoustic-impedance (AI) model based on nonstationary seismic data plays a key role in reservoir predictions. However, the common AI inversion methods are faced with two main shortcomings. First, because of the nonstationary feature of seismic data, a multiparameter inverse problem should be considered to not only estimate AI but also to estimate a time-varying wavelet or a quality factor ( Q) model, leading the problem to be more ill posed. Second, the resolution of the estimated AI is limited due to the band-limited nature of nonstationary seismic data. To address these issues, we develop a new nonstationary seismic AI inversion method. Notably, we develop a deep-learning-aided representation model to replace the nonstationary convolution model to solve the forward problem in inversion. Benefiting from multisource information (seismic data and well-log data) and the powerful nonlinear function fitting ability of deep learning, this model can map high-resolution AI to band-limited nonstationary seismic data without requiring a time-varying wavelet or a Q model. A new deep-learning architecture is developed for processing the spatio-temporal seismic data with better accuracy. In addition, total-variation regularization is adopted to enforce a physically reasonable AI model. The results of our 3D synthetic and field data experiments clearly demonstrate that our method has significant advantages over other common methods in building a high-resolution AI model.

Physicochemical characterization of thermally oxidized rapeseed oil: An insight into combining acoustic diagnostic technique and chemometrics

This study aimed to apply an ultrasonic pulse-echo system to characterize thermally oxidized rapeseed oil. After 60 h of heating treatment (165 ± 5°C), the physicochemical (density, viscosity, acid value, iodine value and polar compounds) and acoustic properties (velocity, acoustic impedance, maximum amplitude of the first echo, difference in amplitude, and area under the curve) of rapeseed oil were measured. Support vector machine, random forest (RF), and backpropagation neural network algorithms were used to establish quantitative prediction models for viscosity and polar compounds based on the acoustic properties of rapeseed oil. The results indicated significant correlations between acoustic impedance and viscosity (R=0.70), as well as between acoustic impedance and polar compounds (R=0.79). Heating treatment reduced oil unsaturation and led to the formation of oxidative and polymeric compounds, which in turn increased the velocity and impedance, while decreasing the other three acoustic features. The RF model yielded the best performance in predicting viscosity (R2=0.7944) and polar compounds (R2=0.8385). These findings highlight that ultrasonic technology not only accurately predicts key quality parameters, but also provides a rapid, non-destructive, and cost-effective alternative to traditional methods for characterizing thermally oxidized rapeseed oil.

Experimental and calculation investigation on perforated Liners’ acoustic impedance

Abstract Acoustic impedance models are the most common method for representing the properties of engine nacelle liners. Although various models have been developed, it is difficult to validate the accuracy due to the limitation of impedance eduction techniques. For obtaining accurate impedance results, a series of perforated liners are manufactured and the impedance of all is measured by using both the microphone array method and in-situ method. The results of the test demonstrate that acoustic resistances are not sensitive to percent open areas, hole diameter, and the face sheet’s thickness, but the Mach number of the grazing flow in the duct can have a considerable effect on resistance. Furthermore, excellent agreement between predictions and measured data gives confidence that the Goodrich perforated liner impedance model is suitable for the design of engine nacelle liner.

Synthesis and Evaluation of New Type Plant Extraction Corrosion Inhibitor

The use of corrosion inhibitors in the development of oil and gas fields is an important means of effectively preventing metal corrosion, at present, the green growth of the oil and gas industry requires low-toxicity, low-residue, easy-to-post-treatment and other environmentally friendly corrosion inhibitors, however, most industrially used corrosion inhibitors such as mercury salts quaternary ammonium salts, and imidazolines are toxic to some degree. In this paper, a plant extract corrosion inhibitor was synthesized, firstly, the purple sweet potato extract was extracted by ethanol, and then the purple sweet potato extract and alkyl halide such as methane were used to produce the purple sweet potato corrosion inhibitor through condensation extraction and other processes, and the corrosion inhibitory performance of the inhibitor was evaluated by the loss-in-weight method, scanning electron microscopy, polarization curves, and impedance spectroscopy. The results show that there is a certain inhibition effect on N80 steel in the simulated stratum water environment, and the retardation rate can reach 91.38% in the gas phase, and the corrosion product morphology and chemical elements on the surface of N80 steel specimens were characterized by SEM, EDS, and it can be observed that a relatively dense protective film was formed after adding purple sweet potato corrosion inhibitor, and the corrosion inhibition rate can be known according to the weightlessness curve, Tafel curve and impedance curve. The corrosion inhibition rate increases with the increase of corrosion inhibitor concentration.

Computational analysis of wind drift and ventilation comfort in a different isolated barrel roof configuration for badminton stadium

The design and construction of the badminton stadium pose a unique wind engineering challenge due to the increase in complaints related to wind drift in badminton tournaments. It is caused by heating ventilation and air conditioning or natural/cross-ventilation systems in the stadium. This paper addresses cross-ventilation efforts on barrel roofs, which are widely used for indoor stadium construction. The computational fluid dynamics analysis is carried out on the flat roof before the barrel roof to validate the wind tunnel data from the literature, and the grid independence is studied. The simulation is performed with a shear stress transport k–ω model with a three-dimensional steady Reynolds-averaged Navier–Stokes (RANS) approach. The cross ventilation for the three different barrel roof configurations with two opening directions is studied in the numerical simulation to understand the influence over volume flow rate and velocity profile near the ground (h = 20 m). From the velocity contour, it is concluded that the longitudinal direction with a height less than 5% from the standard roof (h = 100 mm) performs better than other configurations.

Modified analytical model for predicting the nonlinear acoustic characteristics of perforated sound-absorption structures at high sound pressures

This paper presents a modified model for predicting the nonlinear acoustic characteristics of a microperforated plate at high sound pressure levels with increased accuracy of PARK Model. Based on PARK Model, the acoustic impedance of the cavity behind the plate is taken into account in the equivalent circuit to adjust the velocity in the perforations. The modified model was compared with the previous model to verify its accuracy at high sound pressure levels. Furthermore, to establish that the proposed model also has higher accuracy when considering perforated structures with complex cavities, a four-unit coupled structure (FUCS) composed of four coiled-up space channels was constructed. A finite-element model was used to verify the accuracy of our proposed model. This confirmed that our model calculates the sound-absorption coefficient and average particle velocity in the microholes more accurately than several other models at 155 dB. Experimental assessments of the sound-absorption performance of the FUCS within the 300–1900 Hz range confirmed the accuracy of the model. When considering perforated sound-absorption structures at high sound pressure levels, this model is more accurate than PARK's Model and, therefore, has potential application value in relation to the extreme noise fields experienced in aerospace applications.

Indoor tests of sensor-enabled piezoelectric geocable–geogrid composite structure for slope rehabilitation and monitoring

Sensor-enabled piezoelectric geocables were combined with a geogrid to acquire a sensor-enabled piezoelectric geogrid (SPGG) based on the impedance–strain relationship. Tension, pullout, and straight shear tests were conducted on this SPGG configuration. The tension test results indicated that the tensile strain–normalized impedance curves were exponential in form within the first 7 % of strain and the rate of shift in impedance was independent of the tension loading rate. An excellent correspondence between the peak strength and impedance inflection point was observed in the results of the pullout and straight shear tests. Additional validation of the proposed SPGG was conducted through a collapse test of the reinforced soil slope model. The results indicated that the SPGG-obtained strains were similar to actual strain gauge measurements but provided a larger measurement range and that the SPGG was able to sense real-time vibrations during the slope collapse using a voltage analysis, confirming that the proposed SPGG can simultaneously provide soil reinforcement, strain monitoring of reinforcement materials, and vibration sensing. This research is expected to inform the development of a dynamic and static monitoring, large range, and accurate method for monitoring the conditions of reinforced soil over their entire lifecycles.

Study on the Migration Mechanism of Temporary Plugging Agent in Artificial Fractures of Deep Geothermal Reservoirs Based on the Euler-Euler Multiphase Flow Model

The successful use of temporary plugging diverting fracturing technology requires an understanding of the migration and plugging processes of temporary plugging agents into artificial fractures under high temperature settings. In this study, a multiphase flow model for the migration of temporary plugging agents in artificial fractures was developed using the Euler-Euler framework, and numerical simulations were conducted at elevated temperatures. Various factors, including plugging agent injection velocity, concentration, carrying fluid viscosity, wall temperature, and fracture width, were systematically analyzed to assess their impact on the agent’s migration behavior. Detailed analyses, using cloud diagrams of particle volume fraction, velocity, and turbulence intensity, clarified the underlying mechanisms influencing the migration process. The results indicate that as the injection velocity increases, the height of blockages near the wellbore decreases, while the blockage length initially increases before declining. Increasing the concentration of the plugging agent leads to a rise in blockage height and a shift in the front edge toward the injection point. Enhancing the viscosity of the carrying fluid enables the plugging agent to migrate deeper into the fracture, improving deep plugging effectiveness. While changes in wall temperature have limited impact on blockage morphology, temperatures exceeding the critical threshold of 573K significantly intensify particle migration. Moreover, increasing fracture width enhances both the height and length of blockages, with the optimal plugging effect observed when the plugging agent diameter is approximately one-third of the fracture width.

Mechanism of airborne sound absorption through triboelectric effect for noise mitigation

Mitigating broadband noise with passive airborne sound absorbers has been a long-lasting challenge, particularly for low-frequency anthropogenic sounds below kilohertz with long wavelengths, which require bulky materials for effective absorption. Here, we propose a strategy that utilizes local triboelectric effect and in-situ electrical energy dissipation mechanism for airborne sound absorption. This approach involves a fundamentally different mechanism that converts airborne sound into electricity for energy dissipation, in contrast to conventional mechano-thermal energy conversion mechanisms. We establish an equivalent acoustic impedance model to provide theoretical analysis of the underlying sound absorption mechanisms, with a theoretical maximum mechano-electro-thermal coupling efficiency approaching 100% under optimal conditions. We design fibrous triboelectric composite foam materials accordingly and show their substantially boosted acoustic absorption performance experimentally, where the adoption of diverse triboelectric material pairs validates that a larger difference in material charge affinities intensifies the local triboelectric effect and results in higher acoustic absorbing performance.

Physico-chemical Study of Surface Active Ionic Liquid (SAIL) in Aqueous Inulin Solutions: Density and Speed of Sound Measurements

Colloidal formulations of surface active ionic liquid (SAIL) have substantial benefit as efficient carrier mainly for therapeutic/pharmaceutical agents. In this regard, density (ρ) and speed of sound (u) have been employed to evaluate the diverse interactions/association behaviour of greener SAIL tetrabutylammonium dodecylsulphate (TBADS) (0.222 to 2.2 mmol kg-1) in aqueous inulin solutions (0.0, 0.2 and 0.3% w/w) at five different temperatures ranging from 293.15 K to 313.15 K. The volumetric and acoustic parameters viz. isentropic compressibility (κs), apparent molar volume (Vφ) and compressibility (κs,φ), intermolecular free length (Lf), relative association (RA), specific acoustic impedance (Z) and molar sound number ([U]) have been calculated by using density (ρ) and speed of sound (u) values. The existence of hydrophilic/hydrophobic interactions for TBADS in aqueous inulin solution is suggested by the variations in volumetric parameters, which further supported by various calculated acoustic parameters. Thus, the interactional outcomes can offer implications that stabilized inulin in the presence of SAILs and can be utilized for the optimal biotic actions.

Early detection of cardiac dysfunction using shear wave imaging: insights into reduced cardiorespiratory fitness in childhood cancer survivors

Abstract Background Diastolic dysfunction is thought to be the earliest cardiotoxic sequel after cancer therapy among childhood cancer survivors. Despite many survivors do exhibit reduced cardiorespiratory fitness (CRF) potentially due to cardiotoxicity, current echocardiographic parameters fail to detect hidden diastolic dysfunction early after therapy (1). High frame rate (HFR) shear wave imaging (SWI) is a novel tool that could give insights about myocardial stiffness, which is a key determining factor of diastolic function. Purpose We aimed at testing the ability of SWI to detect early alterations in myocardial stiffness among childhood cancer survivors and its relation with the reduced CRF. Methods Fifty childhood cancer survivors (mean 20 ±3 years) who received chemo-and/or- radiotherapy (mean time after treatment: 4 ±3 years) and thirty-two matched healthy volunteers (HV) were recruited. Conventional as well as HFR echocardiographic images (ca. 1200 frames/second) were acquired at rest using a modified commercial echocardiography machine. All participants underwent an incremental, symptom-limited cardiopulmonary exercise test on a treadmill measuring peak oxygen consumption (VO2 peak). HFR data were analysed offline. An anatomical M mode was drawn along the ventricular septum, and tissue Doppler acceleration maps were extracted to measure SW velocities after mitral valve closure (MVC) (Figure 1). Results Among cancer survivors, left ventricular ejection fraction (LVEF) and global longitudinal strain were significantly lower compared to HV (56 % ±4 vs 59 % ±4, and 17.6 % ±1.6 vs 19.1 % ±1.2, respectively; p <0.001). However, both LVEF and GLS were within the normal range and none of them correlated with the peak VO2 (Figure 2A&B). None of the echocardiographic diastolic parameters (e.g. mitral E, E/e’, left atrial volume or TR jet velocity) showed significant difference between both groups (P > 0.05). The mean SW velocities were significantly higher in cancer survivors compared to HV (3.9 ±0.6 m/s vs 3.2 ±0.3 m/s respectively; p <0.001). Interestingly, SW velocities among cancer survivors showed moderate significant negative correlation with the VO2 peak (r= -0.590, p <0.001) indicating increasing myocardial stiffness as the cardiorespiratory fitness declined (Figure 2C). Conclusions Our data indicate that myocardial stiffness in cancer survivors is significantly increased. We hypothesize that this increased stiffness may at least in part explain the significantly reduced cardiorespiratory fitness in this population. Echocardiographic shear wave elastography appears as a promising non-invasive tool for early detection of diastolic dysfunction in follow-up of childhood cancer survivors.Figure 1.Figure 2.

Improvement of Mechanical and Acoustic Characteristics of Halloysite Nanotube-Reinforced Polyurethane Elastomer Composites and Their Applications.

Polyurethane incorporated with nanofillers such as carbon nanotubes, basalt fibers, and clay nanoparticles has presented remarkable potential for improving the performance of the polymeric composites. In this study, the halloysite nanofiller-reinforced polyurethane elastomer composites were prepared via the semi-prepolymer method. The impact of different halloysites (halloysite nanotubes and halloysite nanoplates) in polyurethane composites was investigated. Scanning electron microscopy, X-ray diffraction, infrared spectroscopy, electronic universal tensile testing, and acoustic impedance tube testing were employed to characterize the morphology, composition, phase separation, mechanical properties, and sound insulation of the samples. The composite fabricated with 0.5 wt% of halloysite nanotubes introduced during quasi-prepolymer preparation exhibited the highest tensile strength (22.92 ± 0.84 MPa) and elongation at break (576.67 ± 17.99%) among all the prepared samples. Also, the incorporation of 2 wt% halloysite nanotubes into the polyurethane matrix resulted in the most significant overall improvements, particularly in terms of tensile strength (~44%), elongation at break (~40%), and sound insulation (~25%) within the low-frequency range of 50 to 1600 Hz. The attainment of these impressive mechanical and acoustic characteristics could be attributed to the unique lumen structure of the halloysite nanotubes, good dispersion of the halloysites in the polyurethane, and the interfacial bonding between the matrix and halloysite fillers.

Entropy generation in radiative motion of tangent hyperbolic nanofluid in the presence of gyrotactic microorganisms and activation energy

In this work, entropy generation is optimized through the application of the second law of thermodynamics. The slip mechanisms, Brownian diffusions, and thermophoresis are elaborated using the tangent hyperbolic nanomaterial model. Magnetohydrodynamic (MHD) fluid is taken into consideration. To characterize the impact of activation energy, a unique model involving the binary chemical reaction is deployed. The effects of mixed convection that is nonlinear in nature, bioconvection, and Joule effect are all taken into consideration. The key partial differential equations (PDEs) are reduced into ordinary differential equations (ODEs) by utilizing appropriate similarity transformations and then solved numerically with the help of a built-in ‘bvp4c’ technique of MATLAB software. Varied flow parameters’ impacts on the nanoparticle volume concentration, entropy number, microorganism concentration, temperature, and velocity fields are analyzed using graphs. Various flow variables are taken into consideration to calculate the total rate of entropy generation. The obtained results show that concentration irreversibility, Joule effect irreversibility, viscous dissipation, and heat irreversibility all influence the entropy. The numerical outcomes were observed by fixing the physical parameters as 0.1<α<4.0, 0.1<M<1.2, 0.1<Nr<2.2, 0.1<Le<2.2, 0.1<Nb<0.4, 0.1<Nt<1.0, 2.0<⁡Pr⁡<5.0, and 0.1<Lb<2.0, as well as their impact on the momentum, thermal, concentration, and microorganism density profiles. From results, an increasing estimate of the variable representing chemical reaction indicates a decline in the concentration. The higher the chemical reaction variable, Hartmann number, and Weissenberg number, the higher the entropy number, while the Bejan number has a contrary behavior. Subsequently, all the outcomes are plotted in graphs and discussed in detail, when subjected to the involving physical quantities.

CHARACTERIZATION OF A FLUVIAL DELTAIC SALT-INFLUENCED SYSTEM FOR CO2 STORAGE USING SEISMIC POST-STACK INVERSION AND SELF-ORGANIZING MAPS IN THE UPPER MIOCENE, ONSHORE LOUISIANA

Basins that have historically been explored for hydrocarbons are now seen through a new perspective for carbon capture and storage. Legacy hydrocarbon reservoirs may now have the potential to become carbon storage targets. The Miocene Sandstone in south Louisiana is a stratigraphic interval that contains favorable zones for carbon storage, and seismic interpretation is a critical tool for characterizing these sands and estimating the amount of possible carbon storage. New workflows leveraging machine learning and seismic inversion can be applied to legacy fields to generate a new estimate for pore space and carbon storage capacity. The study area contains a 3D seismic survey covering 310 mi2 (803 km2) and 16 wells. Using these data, the workflow leverages self-organized maps (SOM) to identify zones of interest both laterally and vertically for carbon storage. SOM provides an uplift in resolution for interpretation compared to single attributes. A model-based acoustic impedance inversion produces porosity information that is used in tandem with SOM outputs. The acoustic impedance results strongly correlate to porosity within the target sands, and the SOM and porosity maps delineate specific sand lobes for potential storage. Wellbore data within the sand lobe align with SOM and inversion results and show rock quality with 26% average porosity and 90 feet gross thickness. The research highlights a project sized target within the middle Miocene containing 10.3 Megatons of estimated CO2 storage. Using SOM and inversion maps in tandem is an effective way for screening an area for carbon storage targets.

The relationship of hemorheological blood values and blood velocity of microcirculatory bloodstream in rats` skin vessels

Non-invasive study of blood rheology is relevant, but quite complex issue. When systemic blood viscosity and hematocrit levels deviate, blood flow indicators in different parts of microvasculature change. Purpose of the study – research of blood flow characteristics in skin microcirculatory bloodstream of rats obtained by high-frequency ultrasound Dopplerography (HFUD) with given changes in rheological blood indicators. The studies were carried out on pubescent male Wistar rats. 3 experimental groups were formed. Group 1 (n = 21) “Hemodilution” – viscosity 1.99 ± 0.02 mPa*s, hematocrit 31.48 ± 0.31%. Group 2 (n = 32) “Reference values” – animals with unchanged blood levels – viscosity 2.84 ± 0.03 mPa*s, hematocrit 41.60 ± 0.3%. Group 3 (n = 32) “Erythrocytosis” – viscosity 3.95 ± 0.04 mPa*s, hematocrit 54.56 ± 0.23%. Dynamic blood viscosity in vitro studies were carried out on oscillatory viscometer. In order to evaluate hematocrit level heparinized whole blood was centrifuged in glass capillaries using; hematocrit values were assessed taking into account sedimentation of formed elements column using a hematocrit reader card. Blood flow in skin microcirculatory bloodstream of rats` left thigh area was estimated by HFUD method using Minimax-Doppler-K hardware and software system, with ultrasound transducer (frequency 20 MHz). Statistical analysis showed the models are correct. Blood indicators of the animals in three experimental groups differed statistically and significantly in terms of blood viscosity and hematocrit. Discriminant analysis was used to determine the relations between rheological blood parameters and characteristics of blood velocity in microcirculatory bloodstream which made it possible to identify the most significant characteristics of blood flow that tend to change depending on altered blood composition. These include: mean systolic velocity Vas (p 0.01), mean velocity Vam (p 0.001), mean volume velocity Qam (p 0.001), vascular resistance index RI (p 0.01) and the percentage of blood cells moving in low-speed H' (p = 0.03). The reliability of selected characteristics was checked with one-way analysis of variance; and their significance in determining membership in “Hemodilution”, “Reference values” or “Erythrocytosis” groups according to HFUD data was confirmed. Based on this analysis classification functions were generated for non-invasive dynamic blood viscosity determination according to ultrasound Dopplerography data.