Low Impedance Research Articles

Tuning Microelectrodes' Impedance to Improve Fast Ripples Recording.

Epilepsy is a chronic neurological disorder characterized by recurrent seizures resulting from abnormal neuronal hyperexcitability. In the case of pharmacoresistant epilepsy requiring resection surgery, the identification of the Epileptogenic Zone (EZ) is critical. Fast Ripples (FRs; 200-600 Hz) are one of the promising biomarkers that can aid in EZ delineation. However, recording FRs requires physically small electrodes. These microelectrodes suffer from high impedance, which significantly impacts FRs' observability and detection. In this study, we investigated the potential of a conductive polymer coating to enhance FR observability. We employed biophysical modeling to compare two types of microelectrodes: Gold (Au) and Au coated with the conductive polymer poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonate) (Au/PEDOT:PSS). These electrodes were then implanted into the CA1 hippocampal neural network of epileptic mice to record FRs during epileptogenesis. The results showed that the polymer-coated electrodes had a two-order lower impedance as well as a higher transfer function amplitude and cut-off frequency. Consequently, FRs recorded with the PEDOT:PSS-coated microelectrode yielded significantly higher signal energy compared to the uncoated one. The PEDOT:PSS coating improved the observability of the recorded FRs and thus their detection. This work paves the way for the development of signal-specific microelectrode designs that allow for better targeting of pathological biomarkers.

Fabrication of MoSe2/Bi3O4Br Z-scheme heterojunction with enhanced photocatalytic performance

Exploring a Z-scheme heterojunction photocatalyst with efficient charge separation and outstanding redox ability is necessary but very challenging. MoSe2 has received much attention as a co-catalyst due to its excellent optical properties. Herein, First-principles density functional theory (DFT) was employed for theoretical calculations of the energy band structure of Bi3O4Br, revealing crossed energy band structures with MoSe2, indicating favorable conditions for heterojunction formation. A solvothermal method was then used to synthesize MoSe2/Bi3O4Br heterostructure photocatalysts with a 2D/2D layered configuration. Characterization via SEM, TEM, DRS, XPS, BET, EIS, and PL confirmed that the MoSe2/Bi3O4Br heterostructure exhibited a larger specific surface area, more active sites, lower impedance, and reduced carrier recombination rate compared to pure Bi3O4Br and MoSe2. These features are advantageous for photocatalytic reactions. The optimized 2.5% MoSe2/Bi3O4Br photocatalyst demonstrated superior performance, achieving nearly 100% photodegradation of RhB under 90 min of simulated sunlight, with an apparent rate constant k value 7.57 times higher than that of Bi3O4Br. The composite photocatalyst exhibited excellent cycling stability over five experiments without significant reactivity attenuation. Finally, a plausible Z-scheme photocatalytic mechanism for MoSe2/Bi3O4Br heterojunctions is proposed based on experimental findings. This study provides new insights for exploring the construction of wide-band semiconductor heterojunctions.

Machine learning assisted discovery of high-efficiency self-healing epoxy coating for corrosion protection

Machine learning is a powerful means for the rapid development of high-performance functional materials. In this study, we presented a machine learning workflow for predicting the corrosion resistance of a self-healing epoxy coating containing ZIF-8@Ca microfillers. The orthogonal Latin square method was used to investigate the effects of the molecular weight of the polyetheramine curing agent, molar ratio of polyetheramine to epoxy, molar content of the hydrogen bond unit (UPy-D400), and mass content of the solid microfillers (ZIF-8@Ca microfillers) on the low impedance modulus (lg|Z|0.01Hz) values of the scratched coatings, generating 32 initial datasets. The machine learning workflow was divided into two stages: In stage I, five models were compared and the random forest (RF) model was selected for the active learning. After 5 cycles of active learning, the RF model achieved good prediction accuracy: coefficient of determination (R2) = 0.709, mean absolute percentage error (MAPE) = 0.081, root mean square error (RMSE) = 0.685 (lg(Ω·cm2)). In stage II, the best coating formulation was identified by Bayesian optimization. Finally, the electrochemical impedance spectroscopy (EIS) results showed that compared with the intact coating ((4.63 ± 2.08) × 1011 Ω·cm2), the |Z|0.01Hz value of the repaired coating was as high as (4.40 ± 2.04) × 1011 Ω·cm2. Besides, the repaired coating showed minimal corrosion and 3.3% of adhesion loss after 60 days of neutral salt spray testing.

Achieving long-life and efficient sodium storage through encapsulating Fe3Se4 nanoparticles within hollow mesoporous carbon nanospheres

The application of Fe3Se4 in sodium-ion batteries is limited due to its poor cycling performance and inferior rate capability. Herein, we employ a multi-step process, involving solution adsorption, molten adsorption, calcination and gaseous selenization, to encapsulate Fe3Se4 nanoparticles within monodispersed hollow mesoporous carbon nanospheres (Fe3Se4@HMCN). The space-confined effect of HMCNs refines Fe3Se4 nanoparticles, compelling Fe3Se4 to adhere to the internal wall of HMCNs. In half-cells, Fe3Se4@HMCN exhibits remarkable rate capability at current densities of 0.1–10 A g−1, and exceptional cycling performance (525 mAh g−1 at 1.0 A g−1 after 400 cycles, 282 mAh g−1 at 5.0 A g−1 after 1800 cycles, 204 mAh g−1 after 2000 cycles at 10.0 A g−1), surpassing both pure HMCNs and bare Fe3Se4. The composite structure significantly improves Na storage performance of Fe3Se4, while Fe3Se4 also contributes the majority of the capacity of the composite. Kinetic studies further unveil rapid Na+ transport, low reaction impedance and a predominant pseudocapacitive effect. In Fe3Se4@HMCN//Na3V2(PO4)3 full cell, Fe3Se4@HMCN sustains a discharge capacity of 175 mAh g−1 after 1200 cycles at 5.0 A g−1. The superior electrochemical performance is attributed to the nanoencapsulation structure based on HMCNs, which synergistically enhances electron conduction, ion transport and structural stability of Fe3Se4.

Current feedback operational amplifier‐based fully orthogonal universal and multifunction filters

SummaryThis paper introduces a second‐order voltage‐mode (VM) multiple‐input single‐output (MISO) universal filter and a second‐order current‐mode (CM) single‐input multiple‐output (SIMO) multifunction filter. The introduced VM MISO universal filter includes a single current feedback operational amplifier (CFOA) and a single voltage follower as active elements, while the introduced CM SIMO multifunction filter contains two CFOAs. Both introduced circuits are orthogonally controllable. In other words, the quality factors can be controlled through a single resistor without affecting the resonance frequencies. Both circuits have low sensitivities and no passive element‐matching conditions. The introduced VM MISO universal filter has a low output impedance. Moreover, to extract the output currents of the proposed CM SIMO from high impedance terminals, second‐generation current conveyor‐based version of the circuit is introduced. Simulations are made through the PSPICE program, where 0.13‐μm IBM CMOS technology parameters are utilized. DC supply voltages are selected as ±0.9 V. In the experiments, AD844s are used, and DC supply voltages are chosen as ±7.5 V.

Greener, Safer and Better Performing Aqueous Binder for Positive Electrode Manufacturing of Sodium Ion Batteries.

P2-type cobalt-free MnNi-based layered oxides are promising cathode materials for sodium-ion batteries (SIBs) due to their high reversible capacity and well chemical stability. However, the phase transformations during repeated (dis)charge steps lead to rapid capacity decay and deteriorated Na+ diffusion kinetics. Moreover, the electrode manufacturing based on polyvinylidene difluoride (PVDF) binder system has been reported with severely defluorination issue as well as the energy intensive and expensive process due to the use of toxic and volatile N-methyl-2-pyrrolidone (NMP) solvent. It calls for designing a sustainable, better performing, and cost-effective binder for positive electrode manufacturing. In this work, we investigated inorganic sodium metasilicate (SMS) as a viable binder in conjunction with P2-Na0.67Mn0.55Ni0.25Fe0.1Ti0.1O2 (NMNFT) cathode material for SIBs. The NMNFT-SMS electrode delivered a superior electrochemical performance compared to carboxy methylcellulose (CMC) and PVDF based electrodes with a reversible capacity of ~161 mAh/g and retaining ~83 % after 200 cycles. Lower cell impedance and faster Na+ diffusion was also observed in this binder system. Meanwhile, with the assistance of TEM technique, SMS is suggested to form a uniform and stable nanoscale layer over the cathode particle surface, protecting the particle from exfoliation/cracking due to electrolyte attack. It effectively maintained the electrode connectivity and suppressed early phase transitions during cycling as confirmed by operando XRD study. With these findings, SMS binder can be proposed as a powerful multifunctional binder to enable positive electrode manufacturing of SIBs and to overall reduce battery manufacturing costs.

Application of Post Stack Acoustic Impedance Inversion to Lateral Rock Property Prediction: A Case Study Eti-field Offshore Niger Delta

This study presents the result of a Model-based seismic inversion technique which was used to invert an acoustic impedance structure within a reservoir interval by intergrating well logs and 3D post stack seismic data obtained from Eti-field offshore Niger Delta. The purpose was to delineate lateral and vertical alternations in subsurface rock properties which is caused by difference in lithofacies within the reservoir interval. This would help to define hydrocarbon fairways better and constrain the range of hydrocarbon zones for field development. The inversion workflow used in this study includes forward modelling of reflection coefficients from a low frequency impedance model driven from well logs and convolution of the reflection coeffiecients with a source wavelet derived from the seismic data. P-impedance inversion analysis at the control well location gave a near perfect correlation of 0.993686 (correlation coefficient of ≈ 99.4 %) between the original P-impedance log, initial guess P-impedance model log and inverted P-impedance log. The estimated error observed was 5533.1 which corresponds to (0.112308) about 11.23 %. Seismic inversion analysis realized an acoustic impedance striucture with P-impedance values ranging from 7000 to about 50000 ft/s*g/cc and having a general increase with depth trend. Impedance slice extracted from the impedance volume at top of the reservoir predicted lateral variations in P-impedance at well control and away from well control. This information can be invaluable in delineating more prospective reservoir zones in the field and thereby enhancing optimum field development which aids in reservoir management decisions.

Common mode far field radiation mechanisms and prediction of a buck converter with cables based on common mode voltage mutation method

AbstractIn the field of electromagnetic compatibility (EMC) research, the knowledge of the formation mechanism of the far field electromagnetic radiation and its prediction is essential for the electromagnetic noise suppression design of a switched mode power supply. This paper investigates the equivalent driving sources of the common mode (CM) current of a Buck converter with cables. Based on the concept of CM voltage mutation, this paper proposes two mechanism models of the same‐direction CM voltage driving mode and the opposite‐direction CM voltage driving mode and derives the approximate analytical formulas for the far field intensity estimation of the horizontal cables. To evaluate the predictive effectiveness of the CM far field radiation model, a 30 MHz very high frequency (VHF) Buck prototype with shielded cables is built and tested, and a shielding shell and low impedance ground conductor suppression designs are then verified. The CM electromagnetic radiation mechanisms of a non‐isolated power converter are demonstrated here. The proposed electromagnetic radiation models, approximate analytical formulas, and improvement design can help to advance the CM radiation analysis and optimization design.

A Generic Strategy to Create Mechanically Interlocked Nanocomposite/Hydrogel Hybrid Electrodes for Epidermal Electronics

HighlightsNanocomposite/hydrogel hybrid electrodes are created with high interfacial toughness by introducing soft microfoams as the mechanically interlocking layer. In the hybrid electrodes, silver nanowires and hydrogels are electrically connected through the porous microfoams, achieving high conductivity and low contact impedance for high-quality biopotential recordings. The microfoam-enabled bonding strategy is generally applicable to diverse polymer substrates.

GelMA/PEDOT:PSS Composite Conductive Hydrogel-Based Generation and Protection of Cochlear Hair Cells through Multiple Signaling Pathways.

Recent advances in cochlear implantology are exemplified by novel functional strategies such as bimodal electroacoustic stimulation, in which the patient has intact low-frequency hearing and profound high-frequency hearing pre-operatively. Therefore, the synergistic restoration of dysfunctional cochlear hair cells and the protection of hair cells from ototoxic insults have become a persistent target pursued for this hybrid system. In this study, we developed a composite GelMA/PEDOT:PSS conductive hydrogel that is suitable as a coating for the cochlear implant electrode for the potential local delivery of otoregenerative and otoprotective drugs. Various material characterization methods (e.g., 1H NMR spectroscopy, FT-IR, EIS, and SEM), experimental models (e.g., murine cochlear organoid and aminoglycoside-induced ototoxic HEI-OC1 cellular model), and biological analyses (e.g., confocal laser scanning microscopy, real time qPCR, flow cytometry, and bioinformatic sequencing) were used. The results demonstrated decent material properties of the hydrogel, such as mechanical (e.g., high tensile stress and Young's modulus), electrochemical (e.g., low impedance and high conductivity), biocompatibility (e.g., satisfactory cochlear cell interaction and free of systemic toxicity), and biosafety (e.g., minimal hemolysis and cell death) features. In addition, the CDR medicinal cocktail sustainably released by the hydrogel not only promoted the expansion of the cochlear stem cells but also boosted the trans-differentiation from cochlear supporting cells into hair cells. Furthermore, hydrogel-based drug delivery protected the hair cells from oxidative stress and various forms of programmed cell death (e.g., apoptosis and ferroptosis). Finally, using large-scale sequencing, we enriched a complex network of signaling pathways that are potentially downstream to various metabolic processes and abundant metabolites. In conclusion, we present a conductive hydrogel-based local delivery of bifunctional drug cocktails, thereby serving as a potential solution to intracochlear therapy of bimodal auditory rehabilitation and diseases beyond.

Design, preparation and electromechanical characteristics analysis of piezoelectric 1-3-type composites with sandwich polymer structures

Aiming at the shortcomings of the traditional 200 kHz 1–3 piezoelectric composites with a thickness of 7.5 mm, which have a lower electromechanical coupling coefficient, lower resolution and larger acoustic impedance, a piezoelectric 1–3-type composites with sandwich polymer structures with higher electromechanical coupling coefficient and lower acoustic impedance was designed in this paper. First, the piezoelectric composites with different volume fractions of piezoelectric ceramics and silicone rubber were simulated by COMSOL software, and the optimal volume fractions of piezoelectric ceramics and silicone rubber were obtained. Second, the first and second lateral mode frequencies of the piezoelectric 1–3-type composites with sandwich polymer structures with different kerf widths were calculated. Then, based on the electromechanical equivalent circuit, the electromechanical characteristics of the piezoelectric 1–3-type composites with sandwich polymer structures were analyzed, and the equivalent performance parameters of the piezoelectric composite were obtained. Compared with other 7.5 mm thickness 1–3 piezoelectric composites, it was found that the electromechanical coupling coefficient of the piezoelectric 1–3-type composites with sandwich polymer structures is significantly increased, and the acoustic impedance is significantly decreased. Therefore, the piezoelectric 1–3-type composites with sandwich polymer structures has great potential advantages in the preparation of high-performance piezoelectric ultrasonic transducers.

Nanoporous graphene-based thin-film microelectrodes for in vivo high-resolution neural recording and stimulation

One of the critical factors determining the performance of neural interfaces is the electrode material used to establish electrical communication with the neural tissue, which needs to meet strict electrical, electrochemical, mechanical, biological and microfabrication compatibility requirements. This work presents a nanoporous graphene-based thin-film technology and its engineering to form flexible neural interfaces. The developed technology allows the fabrication of small microelectrodes (25 µm diameter) while achieving low impedance (∼25 kΩ) and high charge injection (3–5 mC cm−2). In vivo brain recording performance assessed in rodents reveals high-fidelity recordings (signal-to-noise ratio >10 dB for local field potentials), while stimulation performance assessed with an intrafascicular implant demonstrates low current thresholds (<100 µA) and high selectivity (>0.8) for activating subsets of axons within the rat sciatic nerve innervating tibialis anterior and plantar interosseous muscles. Furthermore, the tissue biocompatibility of the devices was validated by chronic epicortical (12 week) and intraneural (8 week) implantation. This work describes a graphene-based thin-film microelectrode technology and demonstrates its potential for high-precision and high-resolution neural interfacing.

Influence of the electrolyte concentration and amount on the performance of textile electrodes in electrostimulation: A systematic study

BackgroundTextile-based stimulation electrodes are a fast-growing research area. With their advantages including flexibility, reusability and the possibility for integration into garments, textile electrodes open up new possibilities that are not yet feasible today, e.g. various self-administrated treatments and rehabilitation based on neuromuscular electrical stimulation (NMES) or transcutaneous electrical nerve stimulation (TENS). So far, most research has shown that textile-based stimulation electrodes perform more reliable when wetted with an electrolyte. However, there is no systematic investigation about which type and amount of electrolyte to use. MethodsIn this study, double-layered textile electrodes have been produced by machine knitting with a size of 3 × 3 cm2. The electrodes were wetted stepwise with a liquid amount from 5 µL up to 320 µL; four levels of sodium chloride (NaCl) concentrations, i.e. 0.9%, 1.5%, 5% and 35%, plus pure deionized water as a reference liquid were chosen. The study analyzed the behavior of the skin-electrode impedance when changing the moisture content and NaCl concentration. In addition, equivalent circuits were modelled for deeper insights into the mechanisms causing an impedance change. ResultsResults showed that the impedance was greatly influenced by the liquid amount with amounts of 5 µL already significantly reducing the impedance compared to dry electrodes, caused by a substantial reduction in resistance. The reactance, on the other hand, was only partly influenced by the liquid amount showing a reduction upon higher liquid amounts only within a range of 5 – 40 µL. Further, a significant influence on the impedance by the presence of ions was found where the skin-electrode systems wetted with NaCl solution were showing generally lower impedances than systems wetted with deionized water. However, within this, no remarkable influence of the NaCl concentration could be observed. As the impedance was found to be very sensitive to the moisture content in the system, it is recommended to introduce standardizations for impedance testing of wet textile electrodes with precisely controlled electrolyte volumes and liquid migration properties to make independent studies of textile electrodes more comparable.

Addressing Triboelectric Nanogenerator Impedance for Efficient CO2 Utilization

AbstractReducing the impedance of a triboelectric nanogenerator (TENG) without power loss is crucial for enhancing its energy conversion efficiency and overall performance. In this paper, a novel signal management structure, based on a newly designed sliding‐mode TENG, aimed at effectively reducing impedance by converting narrow, instantaneous signals into broader ones is presented. This transformation is accomplished by adding a grounded electrode connected to a high‐inductive inductor and fine‐tuning the parasitic capacitance of the dielectric material. Utilizing a highly resistive material like P(VDF–TrFE), a significant improvement in the TENG's performance is achieved, resulting in an increase of output power to 0.352 mW and a decrease in impedance from 3.2 to 0.3 MΩ. This results in a threefold increase in charging speed, which can be attributed to the reduced charge loss and improved matching at lower impedance. Based on these promising findings, the enhanced TENG is successfully connected to power a system for electrochemical CO2 reduction for CO production. This system effectively reduces the required electrochemical reduction potential by ≈15% under real environments.

Hypercrosslinked porous and coordination polymer materials for electrolyte membranes in lithium‐metal batteries

AbstractRechargeable lithium‐metal batteries (LMBs) hold great promise for providing high‐energy density. However, their widespread commercial adoption has been inhibited by critical challenges, for example, the capacity fading from irreversible processes at electrolyte/electrode interfaces and safety concerns originating from the inhomogeneous lithium deposition. Polymer electrolytes benefiting from enhanced electrolyte/electrode contact and low interfacial impedance provide a variable solution to address these challenges and enable a high‐energy and flexible battery system. Although promising, inefficient bulky ionic conductivity and poor mechanical stability confront the stable operation of polymer electrolytes in tangible batteries, which highly requires the development of innovative polymer electrolyte chemistries. Among various polymer materials, microporous polymers stand out due to their abundant porosity and customizable micropore structure, positioning them as promising candidates for next‐generation electrolyte membranes. This review, therefore, summarizes recent advances in electrolyte membranes based on two new chemistries, hypercrosslinked polymers (HCPs) and porous coordination polymers (PCPs). Other microporous polymers, such as covalent organic polymers, porous organic cages, and polymers of intrinsic microporosity, are also discussed with an emphasis on their applications in LMBs. Most importantly, by reviewing the design strategies, synthesis protocols, and performance in LMBs, we gain insights into the design principles of high‐performance electrolyte membranes based on HCPs and PCPs and highlight potential future research directions.

An electromagnetic Hopkinson bar for low wave impedance material and complex stress paths loading tests

The split Hopkinson bar has been widely used for testing the dynamic mechanical properties of various materials. However, there are still difficulties in ensuring stress uniformity when testing some low wave impedance materials such as soft materials and brittle materials and difficulty in achieving true multi-axial and multi-directional synchronous loading experiments and other issues. To overcome these issues, this paper uses an electromagnetic Hopkinson bar for experimental research and introduces its principle and implementation process. Finite element analysis and experimental methods were used to verify the feasibility of the electromagnetic Hopkinson bar in addressing the relevant issues. The superiority of the new device was demonstrated by its capability in performing compression experiments on two typical low wave impedance materials: polymethacrylates (PMMA) and polyurethane (PU), and two-way tension experiments on 2024 aluminum alloy. The results indicate that the electromagnetic Hopkinson bar can effectively solve the problem of uniform stress in low wave impedance materials testing, and can achieve synchronous loading of complex stress paths.

Realizing ultralow overpotential during electrochemical hydrogen generation through photoexcitation of chromium disulphide

Designing efficient electrocatalysts for hydrogen generation is desirable for electrochemical water splitting and fuel cells as they are a part of clean and sustainable energy system. Here, we are reporting the utilization of clean method for the production of platinum deposited chromium disulphide (CrS2) particles and their application for hydrogen generation via photo-assisted electrochemical water splitting. Photoelectrochemical studies of CrS2 show a close to zero onset potential, ultralow overpotential (8.3 mV), small Tafel slope (54 mV/decade), and low impedance (1.8 Ω) in acidic media. The chronoamperometric study of prepared catalyst reveals that it is sustainable as having a long-term stability. The post electrochemical study of electrode surface reveal the presence of traces of Pt deposited over CrS2. The detailed compositional analysis of electrolyte has also been performed. This study opens up a pathway for electrochemically modifying the composition of the catalysts for harnessing their potential as efficient electrocatalyst during water splitting.

Controlling the Supramolecular Architecture Enables High Lithium Cationic Conductivity and High Electrochemical Stability for Solid Polymer Electrolytes

AbstractSolid polymer electrolytes (SPEs) are long sought after for versatile applications due to their low cost, light weight, flexibility, ease of scale‐up, and low interfacial impedance. However, obtaining SPEs with high Li+ conductivity (σ+) and high voltage stability to avoid concentrated polarization and premature capacity loss has proven challenging. Here a stretchable dry‐SPE is reported with a semi‐interpenetrating, supermolecular architecture consisting of a cross‐linked polyethylene oxide (PEO) tetra‐network and an alternating copolymer poly(ethylene oxide‐alt‐butylene terephthalate). Such a unique supermolecular architecture suppresses the formation of Li+/PEO intermolecular complex and enhances the oxidation stability of PEO‐based electrolyte, thus maintaining high chain segmental motion even with high salt loading (up to 50 wt%) and achieving a wide electrochemical stability window of 5.3 V. These merits enable the simultaneous accomplishment of high ionic conductivity and high Li+ transference number (t+) to enhance the energy efficiency of energy storage device, and electrochemical stability.

Wave-absorbing performance of alumina thin-walled hollow particles under freezing condition

The reliability of the absorbing layer is crucial for realizing protective engineering’s protection function. However, the typical wave-absorbing material, sand, is unable to fulfill its intended wave-absorbing function in areas with seasonally frozen soil. This is because the internal pores of the material become filled with ice and the particles freeze. To address this issue, alumina thin-walled hollow particles were chosen as a new wave-absorbing material. These particles can introduce the gas phase into the absorbing layer which is essential for attenuating the stress waves and its wave-absorbing capacity under freezing conditions was investigated by the split Hopkinson bar (SHPB) test. According to the test data, the alumina thin-walled hollow particles are less dense than sand and have a lower wave impedance, allowing them to reflect more incident energy. Moreover, these particles have a better capacity for dissipating the absorbed energy, as compared to sand. Under freezing circumstances, the average transmittance coefficient of alumina thin-walled hollow particles is only 21.95% to 49.30% of ordinary sand. Additionally, the particle size positively correlates with the capacity for wave-absorption. The capacity of alumina thin-walled hollow particles to shatter and release the gas phase under impact stress significantly increases the compressibility of the absorbing layer under freezing conditions, which accounts for their enhanced wave-absorbing effectiveness. The stress-strain curve specifically manifests as a smoother curve and a longer stage of plastic energy dissipation. Other than that, the dynamic deformation modulus of the material and peak stress is lower, while the peak strain is larger. The findings of this study provide a low-cost, high-reliability solution to the problem of frost damage in the absorbing layer in regions with seasonal freezing.

Lateral Rock Characteristic Evidence of Hydrocarbon Restoration from Post-Stack Impedance Inversion: A Case Study of ZED-field Offshore Niger Delta

Lateral predictions of rock properties that are descriptive of a reservoir have been studied using a model-established seismic inversion approach that was used to convert input seismic data into an acoustic impedance structure to optimize hydrocarbon restoration in the field. This was actualized by integrating wireline logs and 3D post stack seismic data procured from ZED-Field offshore Niger Delta. The inversion system employed in this study comprises of forward modelling of reflection coefficients starting with a low-frequency impedance model induced from well logs and convolution of the reflection coefficients with the source wavelet extracted from the seismic input. P-impedance analysis at reservoir C5000 delineated from the control well gave a near perfect correlation of 0.998109 (≈ 99.8 %) between the original P-impedance log, initial P-impedance model log and inverted P-impedance log with an estimated error of 0.0616932 which is about (6.16%). Seismic inversion analysis realized an acoustic impedance structure with P-impedance values ranging from 3801 to 11073.0m/s*g/cc and having an overall increase with depth tendency. Specifically, a low-impedance structure was observed at the reservoir window that can be profiled laterally elsewhere from the existing wells. Impedance slices extracted from the impedance volume at the top and base of reservoir C5000 clearly showed low impedance values away from the existing wells which are evidence of new hydrocarbon prospects (hydrocarbon-charged sands) in the field that can be explored for improved hydrocarbon recovery and field development. Therefore, the realized attribute could supply litho-fluids knowledge inside the current reservoirs, and likewise aid in defining probable hydrocarbon regions of low impedance that can be tested with the input seismic to boost the interpretation of reservoir attributes with feasible integration to seismic stratigraphy for improved reservoir prediction away from the extant wells. This information can be invaluable in delineating more prospective reservoir zones in the field, and thereby enhancing optimum field development which aids in reservoir management decisions.