Isolation Capability Research Articles

Intelligent Completion Enables Zonal Isolation Offshore Malaysia

_ This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper IPTC 22882, “Advancement of Openhole Gravel Pack and Zonal Isolation With Selective Intelligent Completion in Deepwater Malaysia,” by Elvy Samuel, SPE, Noppanan Nopsiri, and Lee Chan Fong, PTTEP, et al. The paper has not been peer reviewed. Copyright 2023 International Petroleum Technology Conference. _ As fields mature, drilling and completion design and execution for infill development become more challenging. In a deepwater environment, one strategy is to target several reservoir packages in a single wellbore. This technique frequently presents technical challenges, however, because penetrating different zones requires active reservoir management, an allowance for zonal isolation, and an adequate response to potential crossflow. The complete paper presents a completion strategy implemented in an intelligent well completed in the Malaysian deepwater Block K. Introduction The SNP Field is 125 km offshore Sabah in approximately 1350–1400 m water depth. The field crosses the boundary between Block K and Block G, approximately 15 km from the Kikeh floating production, storage, and offloading (FPSO) facility. The field commenced Phase 1 in 2011 with the completion of nine oil producers as openhole gravel packs (OHGPs) and five water injectors with expandable sand screens at the sandface. Phase 2 development, partially covered in the complete paper, commenced in the third quarter of 2021 with three standard oil producers and one smart producer well. All SNP Phase 2 wells were completed as OHGPs targeting various sand reservoirs in a common pressure regime. The well discussed in the complete paper addressed subsurface uncertainties related to depth and the pressure differential between the upper zone (UZ) and the lower zone (LZ) and the isolation requirements of the middle zone (MZ) by implementing an intelligent completion architecture with an OHGP with zonal isolation on the sandface. The flow diversion between the producer zones would be achieved through the deployment of an intermediate completion coupled with an intelligent completion architecture in the upper completion. The well was placed on production in the first quarter of 2022 to the Kikeh FPSO, achieving the targeted rates solids-free. Gravel-Pack Design In this field, the fracture pressure window is marginal, suggesting that a conventional OHGP approach would be challenging. Adding to this complexity is the zonal-isolation requirement. To achieve the objective of complete openhole (OH) coverage and to enable zonal isolation simultaneously, shunt-tube technology was identified as critical. The selection of shunt-tube technology allows the following achievements: - Premature screenout mitigation, because the technique is a proven system that enables the slurry to bypass any restriction in the OH/screen annulus - Zonal-isolation capabilities by combining shunted sand screens and OH mechanical packers with selective shunt-tube isolation capabilities - Application of diverter valves, crucial in fields with marginal fracture pressure windows

EFraS: Emulated framework to develop and analyze dynamic Virtual Network Embedding strategies over SDN infrastructure

The integration of Software-Defined Networking (SDN) into Network Virtualization (NV) significantly enhances network management, isolation, and troubleshooting capabilities. However, it brings forth the intricate challenge of allocating Substrate Network (SN) resources for various Virtual Network Requests (VNRs), a process known as Virtual Network Embedding (VNE). It encompasses solving two intractable sub-problems: embedding Virtual Machines (VMs) and embedding Virtual Links (VLs). While the research community has focused on formulating embedding strategies, there has been less emphasis on practical implementation at a laboratory scale, which is crucial for comprehensive design, development, testing, and validation policies for large-scale systems. However, conducting tests using commercial providers presents challenges due to the scale of the problem and associated costs. Moreover, current simulators lack accuracy in representing the complexities of communication patterns, resource allocation, and support for SDN-specific features. These limitations result in inefficient implementations and reduced adaptability, hindering seamless integration with commercial cloud providers. To address this gap, this work introduces EFraS (Emulated Framework for Dynamic VNE Strategies over SDN). The goal is to aid developers and researchers in iterating, testing, and evaluating VNE solutions seamlessly, leveraging a modular design and customized reconfigurability. EFraS offers various functionalities, including generating real-world SN topologies and VNRs. Additionally, it integrates with a diverse set of evaluation metrics to streamline the testing and validation process. EFraS leverages Mininet, Ryu controller, and OpenFlow switches to closely emulate real-time setups. Moreover, we integrate EFraS with various state-of-the-art VNE schemes, ensuring the effective validation of embedding algorithms.

Full-band vibration isolation and energy absorption via cuttlebone-inspired lattice structures

In diverse engineering disciplines, vibration isolation technology is indispensable for ensuring stability, accuracy, and safety. Traditional vibration isolation methods often compromise structural rigidity, particularly at ultra-low frequencies, presenting a significant challenge. To solve this issue, this study introduces cuttlebone-inspired lattice structures (CILS), which are fabricated using selective laser sintering (SLS) 3D printing and have an excellent energy absorption capacity as well as enhanced vibration isolation. This innovation enables effective low-frequency, full-band vibration isolation while preserving structural stiffness. CILS have an excellent energy absorption capacity of 1.411 J/mm3, which is due to the maintenance of a zero Poisson's ratio even under significant deformation (a strain of 0.5). Vibration isolation tests revealed that CILS provide comprehensive isolation across the frequency spectrum of 5–36.77 Hz. Furthermore, CILS effectively extends full-band vibration isolation to medium and high-frequency bands encompassing 56.01 Hz to 2000 Hz. The proposed design strategy offers a novel approach by integrating high energy absorption with extensive isolation capabilities, effectively overcoming traditional limitations to enhance engineering stability and safety.

Harnessing Bacillus cereus from Surabaya Seawater for Enhanced Diesel Fuel Bioremediation in Tropical Ocean

Hydrocarbon is one of the primary organic pollutants that contaminate seawater. Most hydrocarbons which pollute the sea waters of Indonesia are the constituents of diesel fuel. This condition emphasizes the need to develop a bioremediation strategy for diesel fuel pollution in the country. A successful plan for bioremediation is primarily determined by the choice of the bacterial agent, which can be isolated from the polluted seawater. Furthermore, the setup must consider the characteristics and capability of the bacterial isolates to degrade diesel fuel. This study thus aimed to analyze the potential of Bacillus cereus isolated from the polluted seawater of Surabaya, East Java, Indonesia, as a bioremediation agent. The results of bacterial density, pH measurements, TPH and GC-MS assays indicated that the locally isolated Bacillus cereus could significantly reduce the hydrocarbon concentrations. More importantly, after 14 days of bioremediation, the polluting diesel fuel was categorized as biodegradable based on the BOD:COD ratio. This study shows that Bacillus cereus has excellent potential for bioremediating hydrocarbon contaminants in tropical seawater. HIGHLIGHTS Bacillus cereus from Surabaya's polluted waters fights diesel pollutants effectively. Bacillus cereus degrades hydrocarbons efficiently over two weeks, proving its bioremediation potential. Rise in BOD:COD ratio indicates Bacillus cereus' effective reduction of complex organics. GC-MS shows Bacillus cereus transforms hydrocarbons into shorter chains systematically. Bacillus cereus offers an eco-friendly solution for diesel pollution in tropical climates, urging further exploration. GRAPHICAL ABSTRACT

Enhancing Diversity and Isolation Performance for a Four-Port Mimo Antenna in FR-1 5G Frequency Bands

The paper aims to improve the diversity parameters and isolation of a four-port Multiple-Input Multiple Output (MIMO) antenna configured as 4 × 1 for the 5G-NR FR-1 N78/77/48 band. The 4-port MIMO design entails the incorporation of dual sets of monopole antennas. Each pair of monopoles in this configuration arranges the second monopole to mirror the first one within its set. The MIMO antenna design incorporates Rogers RO3003 substrates with a ϵr of 3.2. The antenna size is compact, with dimensions of 34 × 129.5 × 1.6 mm3. The design of the four-port MIMO antenna introduced parasitic decoupling elements between the antennas, a defected ground structure (a T-shaped stub), and the incorporation of a grounding branch on the ground plane. These measures effectively mitigate the coupling between the antennas. The antenna functions within the frequency range of 2.25 GHz to 4.25 GHz, offering a bandwidth of 2 GHz with a peak gain of 4.0 dBi at 3.52 GHz. The diversity performance of the suggested MIMO antenna is evaluated using the parameters TARC, E.C.C., D.G., CCD/CCL, and M.E.G. The values obtained are as follows: starting from −15 dB, 0.0408, 9.989 dB, 0.08 bits/s/Hz, and 0.48 dB, respectively. According to both simulated and measured data, the MIM0 antenna system design presents good isolation capabilities, excellent diversity performance, and robust impedance matching. This can be a good option for FR-1 5G-NR N78/77/48 band communication.

Machine Learning-Driven Design Optimization of Buckling-Induced Quasi-Zero Stiffness Metastructures for Low-Frequency Vibration Isolation.

Metastructures, artificial arrangements of micro/macrostructures, possess unique properties and are of significant interest in aerospace, stealth technology, and various other applications. Recent studies have focused on quasi-zero stiffness metastructures, providing an outstanding vibration isolation capability. However, existing methods are constrained to low preloads and lack the consideration of structural analysis, despite their intended use in practical structures. This study introduces metastructures with quasi-zero stiffness characteristics under high preloads by inducing local buckling. An optimization framework combining deep reinforcement learning and finite-element analysis is employed to derive an optimal model that considers both structural safety and quasi-zero stiffness characteristics. To validate the optimization results, quasi-zero stiffness metastructures are fabricated via 3D printing, and compression and vibration experiments are conducted. The fabricated metastructures exhibit quasi-zero stiffness characteristics under a high target preload along with outstanding vibration reduction performance, even in the low-frequency range.

Research on the effectiveness of a new-type bearing for structural seismic and vibration dual control

The burgeoning expansion of subway systems has heightened the significance of subway-induced vibrations and their impact on nearby structures. Addressing the dual challenges of mitigating subway-induced vibrations and ensuring structural seismic safety is garnering increasing attention. This study introduces a new-type seismic and vibration dual control isolation bearing that leverages the deformability of rubber. This bearing consists of a thick rubber bearing and a traditional horizontal rubber bearing, which are decoupled in motion and responsible for vertical vibration isolation and horizontal seismic isolation, respectively. A scaled model was constructed of an actual structure to assess the effectiveness of this bearing, conducting shaking table tests with inputs simulating typical subway-induced vibrations and seismic motions. Our findings reveal that the bearing successfully meets predefined isolation and vibration control objectives. Regarding subway-induced vibration loads, it markedly diminishes peak vertical acceleration responses. Frequency-wise, it effectively attenuates high-frequency responses while amplifying low-frequency ones. Notably, increasing damping does not significantly improve vertical vibration isolation. Regarding seismic loads, by aptly configuring the horizontal seismic isolation parameters, the bearing achieves targeted seismic isolation objectives. Furthermore, this new bearing demonstrates certain vertical isolation capabilities, distinguishing it from traditional horizontal rubber isolation bearings.

An overview of green roof acoustic performance

This comprehensive review provides an in-depth examination of the acoustic performance of green roofs within urban and built environments over the past 15 years. Green roofs, characterized by their vegetative cover and substrate layers, offer a multifaceted solution to address challenges associated with urban noise pollution. The objective of this review is to synthesize existing literature, emphasizing key studies and methodologies employed to assess the noise reduction and sound isolation capabilities of green roofs. Factors influencing green roof acoustic performance, such as plant species selection in the plant layer, soil distribution, moisture content, and compaction level in the vegetation layer, as well as the overall roof design in terms of shapes and building configuration, are discussed in detail. Additionally, the impact of overall roof design, including shapes and building configuration, is explored. The relevant sound absorption coefficient and insertion loss values, drawn from the existing literature, will be reported. By systematically analyzing empirical findings, this overview offers valuable insights into the potential of green roofs as sustainable components for noise mitigation in building construction, contributing to the development of more resilient and harmonious urban landscapes.

Determining the Metabolic Processes of Metal-Tolerant Fungi Isolated from Mine Tailings for Bioleaching

This study examined the metal tolerance and organic acid-producing capabilities of fungal isolates from South African tailings to assess their potential for future bioleaching applications. Four isolates were chosen for additional examination based on their capacity to generate organic acids and tolerance to metals. In terms of tolerance to Al, Zn, Ni, and Cr, these four isolates—Trichoderma, Talaromyces, Penicillium_3, and Penicillium_6—displayed varying degrees of resistance, with Trichoderma displaying a better metal tolerance index. The growth rates under metal stress varied among the isolates, with Trichoderma displaying the highest growth rates. In high-performance liquid chromatography results, citric acid emerged as the primary organic acid produced by the four isolates, with Trichoderma achieving the highest yield in the shortest timeframe. Gas chromatography–mass spectrometry results showed that the citric acid cycle is one of the main pathways for organic acid production, though other pathways related to lipid biosynthesis and carbohydrate metabolism also play significant roles. Three compounds involved in furfural breakdown were abundant. Using KEGG, a link between these compounds and the citric acid cycle was established, where their breakdown generates an intermediate of the citric acid cycle.

Optimization of Load Distribution Method for Hydropower Units Based on Output Fluctuation Constraint and Double-Layer Nested Model

During the load distribution of hydropower units, the frequent crossing of vibration zones as well as large output fluctuations affect the stability of the power station. A multi-objective double-layer intelligent nesting model that considers the constraint of the output fluctuation of units is proposed to address these problems. The nonlinear constraint unit commitment optimization model layer is built based on outer dynamic programming, and the load distribution optimization model layer is constructed based on the improved biogeography-based optimization algorithm. Simultaneously, the unit output fluctuation constraint is established based on whether the unit combination changes in order to limit the unit output fluctuation. The results of this model indicate that compared with traditional load allocation models, the application of the method proposed in this paper can reduce the fluctuation range of unit output by 85.01%. In addition, except for the inevitable vibration zone crossings during startup and shutdown processes, the unit does not cross the vibration zone during operation, which greatly improves the unit’s vibration isolation and optimization capabilities. The multi-objective double-layer intelligent nested model proposed in this paper has significant advantages in the field of load allocation for hydropower units. It effectively improves the stability and reliability of unit operation, and this method can be applied to practical load allocation processes. It is of great significance for the research on load allocation optimization of hydropower units.

Adaptive optimal fault-tolerant vibration control and sensitivity analysis of semi-active suspension based on a self-powered magneto-rheological damper

To reuse the energy dissipated by vehicle suspension, a semi-active suspension with a self-powered magneto-rheological damper is proposed. An electromechanical coupling model of self-powered semi-active suspension is established. The energy conversion efficiency is defined and investigated by changing the electrical parameters. By considering unmodeled dynamics and perturbation values, an adaptive optimal fault-tolerant control algorithm is proposed to ensure the vibration-isolation performance. The robust index of the adaptive optimal fault-tolerant control algorithm is constructed using the Lyapunov equation and evaluated by changing the key parameters. The sensitivity of the key parameters to the damping force is investigated using a grey relation analysis approach. Furthermore, multi-objective optimization between the vibration-isolation capability and energy harvesting is conducted. Via analysis, the proposed suspension can harvest more energy near the second resonance range. Compared to passive control and self-powered mode, the adaptive optimal control algorithm mitigates vibration more significantly in the time and frequency domains, respectively, under stochastic excitation. The robust index is most sensitive to inductance and the diameter of the magnetism cylinder. The length of the damping channel and the diameter of the magnetism cylinder influence the sensitivity of key parameters to the damping force most obviously.

Isolation, identification and osteogenic capability analysis of mesenchymal stem cells derived from different layers of human maxillary sinus membrane.

To discover the populations of mesenchymal stem cells (MSCs) derived from different layers of human maxillary sinus membrane (hMSM) and evaluate their osteogenic capability. hMSM was isolated into a monolayer using the combined method of physical separation and enzymatic digestion. The localization of MSCs in hMSM was performed by immunohistological staining and other techniques. Lamina propria layer-derived MSCs (LMSCs) and periosteum layer-derived MSCs (PMSCs) from hMSM were expanded using the explant cell culture method and identified by multilineage differentiation assays, colony formation assay, flow cytometry and so on. The biological characteristics of LMSCs and PMSCs were compared using RNA sequencing, reverse transcription and quantitative polymerase chain reaction, immunofluorescence staining, transwell assay, western blotting and so forth. LMSCs and PMSCs from hMSMs were both CD73-, CD90- and CD105-positive, and CD34-, CD45- and HLA-DR-negative. LMSCs and PMSCs were identified as CD171+/CD90+ and CD171-/CD90+, respectively. LMSCs displayed stronger proliferation capability than PMSCs, and PMSCs presented stronger osteogenic differentiation capability than LMSCs. Moreover, PMSCs could recruit and promote osteogenic differentiation of LMSCs. This study identified and isolated two different types of MSCs from hMSMs. Both MSCs served as good potential candidates for bone regeneration.

Nonlinear dynamics analysis of the attachment system and design of variable stiffness connecting bracket based on the complete aero-engine system

During the operation of the aero-engine, the attachment and brackets are subjected to various complex internal and external loads, which can pose risks to the structural integrity of the engine. To address this issue, this paper introduces a variable stiffness bracket designed for vibration reduction in the attachment system. Firstly, a finite element model (FEM) of the aero-engine was established using the Lagrangian method, incorporating the dual rotor-bearing system and bracket-attachment system. Subsequently, the vibration response of the system was solved using the Runge-Kutta method. The sources and propagation paths of vibration within the system were identified. Lastly, leveraging the material properties of Shape Memory Alloy (SMA), a stiffness-adjustable bracket for the aircraft engine was proposed to achieve active vibration reduction in the system. The results demonstrate that the variable stiffness bracket effectively reduces the resonance amplitude and frequency in the attachment system, exhibiting excellent vibration reduction and isolation capabilities.

4D printing of customizable and reconfigurable mechanical metamaterials

Customizable and reconfigurable mechanical behavior is critical for self-adaptive low-frequency vibration isolators operating in dynamic environments. Herein, the mechanical metamaterials with customizable and configurable geometries, material stiffnesses, cushioning properties, and vibration isolation capabilities are fabricated using a 4D printed multi-material system. The metastructure is characterized by the connection of a flexural beam structure and a collapsible straw structure. At the unit level, the stiffness characteristics are analyzed by geometric and theoretical mechanical models. The effect of geometric parameters and material composition on the stiffness behavior of multi-material metamaterials is investigated. Metamaterials' customizable and configurable characteristics are examined by the quasi-static compression mechanical properties, cushion performances, and vibration isolation capabilities under varying geometric parameters and material compositions. Finally, the reprogrammable stiffness of the metamaterial is demonstrated through the modification of geometric parameters utilizing the shape memory properties in 4D printing. The customizable and configurable metamaterials inspire the next generation of cushioning and vibration isolators, holding significant promise for applications demanding superior vibration isolation performances in dynamic environments.

APPLICATION OF LINER SYSTEMS WELLABLE ELASTOMERIC PACKERS FOR WELL CONSTRUCTION

The application of liner systems featuring swellable elastomeric packers in well construction has emerged as a groundbreaking development within the oil and gas industry. This technology, which will be discussed in detail in this paper, addresses critical wellbore challenges, providing an in-depth exploration of its advantages and the transformative effects it has on well construction. Swellable elastomeric packers, a key component of these liner systems, play a pivotal role in overcoming various wellbore obstacles. Their unique design allows them to expand when in contact with wellbore fluids, establishing a robust and reliable seal. This characteristic renders them adaptable to a diverse array of applications, showcasing their versatility. These packers are particularly instrumental in creating a barrier between different geological formations or production zones within a well. By expanding and isolating specific zones, they effectively prevent undesirable fluid flow between them. This not only optimizes reservoir management but also enhances overall production efficiency. In addition to their zonal isolation capabilities, swellable elastomeric packers contribute significantly to the integrity of well casings. Acting as an additional protective layer, they guard against corrosion, high-pressure zones, and other challenges encountered in harsh downhole conditions. This protective function becomes especially crucial in ensuring the longevity and reliability of wells subjected to demanding environments. For wells prone to sand production, the deployment of swellable packers proves invaluable. These packers isolate and stabilize sand-prone zones, mitigating the ingress of sand and preserving productivity. Often overlooked in well completion design is the preparation for abandonment. The incorporation of blind pipe sections with swellable packers along the horizontal section of the liner in the new completion procedure has become an effective tool for safely and efficiently shutting down horizontal wells. A noteworthy advantage of liner systems with swellable packers is their cost-effectiveness in providing zonal isolation and ensuring casing integrity. By reducing reliance on traditional cementing methods, these systems offer economic solutions without compromising performance. Their adaptability allows for customization to specific wellbore needs, making them compatible with various completion techniques and wellbore configurations. In conclusion, the incorporation of liner systems featuring swellable elastomeric packers marks a significant leap forward in well construction technology. The versatility and effectiveness of these packers address critical wellbore challenges, providing solutions that optimize reservoir management, enhance production efficiency, and contribute to the overall integrity of oil and gas wells. The purpose of this article was to examine samples and establish the conditions for their application. Keywords: liner systems, swellable elastomeric packers, well construction, zonal isolation, swelling rate, liner hanger.

SAM-SFM: High-Efficiency and High-Resolution Tandem Mass Spectrometry Enabled by Sinusoidal Amplitude Modulation of Multiple Sinusoidal Frequency-Modulated Waveforms.

In miniature ion trap mass spectrometry, achieving a balance between isolation resolution and efficiency is a formidable challenge. The presence of absorption curves causes target ions to inadvertently absorb energy from AC signal components near their resonant frequencies. To mitigate this issue, SAM-SFM waveforms introduce a parameter known as the decreasing factor. Unlike SWIFT waveforms, SAM-SFM's spectral profile intentionally departs from a rectangular window, adopting an arch-shaped excitation window to minimize the impact on target ions and improve ion isolation efficiency. SAM-SFM waveforms have the advantage of low computational complexity, enabling real-time computation using an embedded FPGA technology. Regardless of any parameter changes, the FPGA can consistently guarantee waveform output within 1 μs. This not only enhances throughput but also eliminates the need for a PC in miniature mass spectrometry devices. The performance of SAM-SFM has been validated on an improved "Brick" miniature ion trap mass spectrometer. Comparative experiments with SWIFT waveforms confirm the lossless unit-mass isolation capabilities of SAM-SFM. This waveform has the capability to simultaneously isolate multiple target ions, even allowing for the lossless isolation of ions with lower abundance within isotopic clusters, albeit at the cost of requiring extended isolation durations.

Screening and characterization of endophytic bacteria isolated from celery with the potential to promote plant growth

Abstract. Nuriyanah, Widowati T, Masnang A, Nurjanah L, Novilasari D, Lekatompessy SJR, Simarmata R. 2023. Screening and characterization of endophytic bacteria isolated from celery with the potential to promote plant growth. Biodiversitas 24: 6897-6904. Endophytic bacteria that inhabit plant tissue contribute to the enhancement of host plant growth by producing secondary metabolites. They can improve plant growth by phytohormone modulation and nutrient uptake. In addition, endophytic bacteria can increase plant health and tolerance by antibiotic and hydrolytic enzyme production. This study aims to screen and characterize endophytic bacteria of celery as plant growth promoter agents. Thirty endophytic bacteria were isolated successfully from part of the celery plant using the spread plate and plant piece method which grew at Nutrient Agar media. Based on the characterization assay, 30 isolates may produce IAA with various concentrations of 0.21-7.18 mg/L. In addition, 3 of 30 isolates had phosphate solubilizing activity, in different indexes ranging from 0.71-1.43. Twenty-one isolates were able to grow in an N-free medium, indicating the capability of isolates to fix nitrogen qualitatively. The hydrolytic enzymes assay resulted in 14 amylolytic, 17 proteolytic, and 12 cellulolytic activities. In addition, nine of 30 isolates show multi-activity in amylase, protease, and cellulase enzyme production. Based on the screening results, there are four potential isolates (SLBg 1.2; SLBg 1.5; SLAg 1.1, and SLAg 1.5) as promising plant-growth promoters and were molecularly identified as members of the Bacillus genus. These isolates can be developed as biofertilizers for supporting the cultivation of celery plants.

A dual-port, single-fed, integrated microwave and mm-wave MIMO antenna system with parasitic decoupling mechanism for 5G-enabled IoT applications

The integration of microwave and mm-wave antenna is recognized as a promising solution to ensure backward compatibility while effectively utilizing available space for 5G-enabled modern IoT devices. This paper proposed a very compact size multi-band dual-port MIMO antenna module, aiming to provide complete coverage in microwave frequency bands, including 2.4 GHz, 3.5 GHz, 5.3 GHz, and 7.5 GHz, along with 5G mm-wave bands such as 28 GHz. This is achieved through a common feedline by incorporating a semi-circular slotted monopole with strategically positioned quarter-wavelength metallic stubs on a partial ground plane. The proposed antenna exhibited -10 dB impedance bandwidths of 22.6% (2.16–2.71 GHz), 17.9% (3.36–4.02 GHz), 9.4% (5.18–5.69 GHz), 15.9% (7.29–8.55 GHz), and 15.5% (26.02–30.39 GHz) across diverse frequency bands. To attain compactness and high isolation capabilities, a composite three-dimensional parasitic element is employed as a decoupling structure to alleviate significant interference among closely positioned radiating elements. The proposed antenna provides radiation efficiency of > 85%, achieving necessary peak gains of 2.32 dBi, 3.46 dBi, 4.15 dBi, and 5.32 dBi at respective microwave frequencies. While in mm-wave frequency bands, radiation efficiency exceeds 95% having a measured realized gain of 6.2 dBi at 28 GHz. The proposed design successfully maintains an average isolation of > 28 dB in all frequency bands. The suggested MIMO configuration demonstrates outstanding diversity performance, which is evidenced by ECC, DG, MEG, CCL, and TARC.

Bio-augmentation and bio-stimulation with kenaf core enhanced bacterial enzyme activities during bio-degradation of petroleum hydrocarbon in polluted soil

Indigenous micro-organisms often possess the ability to degrade petroleum hydrocarbon (PHC) in polluted soil. However, this process can be improved by supplementing with nutrients or the addition of more potent microbes. In this study, the ability of kenaf-core to stimulate the PHC degradation capability of microbial isolates from PHC polluted soil samples was evaluated. The standard experimental methods used in this study include: the digestion and analysis of the physico-chemical properties of petroleum hydrocarbon contaminated and non-contaminated soil samples; evaluation of petroleum hydrocarbon biodegradation using bio-augmentation and bio-stimulation (with kenaf-core) treatments; and, determination of soil microbial enzyme activities. Results from this study show that K, Na, total nitrogen, organic carbon, exchangeable cations, and heavy metals were found to be significantly (P < 0.05) higher in the polluted soil than in the non-polluted soil. Also, the polluted samples had pH values ranging from 5.5 to 6.0 while the non-polluted samples had a pH of 7.6. The microbial enzyme activities were comparatively lower in the polluted soils as compared to the non-polluted soil. The percentage degradation in the kenaf-core treated samples (AZ1T2—78.38; BN3T2—70.69; OL1T2—71.06; OT1T2—70.10) were significantly (P < 0.05) higher than those of the untreated (AZ1T1—13.50; BN3T1—12.50; OL1T1—10.55; OT1T1—9.50). The degradation of petroleum hydrocarbon in the bio-augmented and bio-stimulated treatments increased with increasing time of incubation, and were higher than that of the untreated sample. Comparatively, the treatment with a combination of kenaf-core and rhamnolipid exhibited a significantly (P < 0.05) higher degradation rate than that of the treatment with only kenaf core or rhamnolipid. While, the bio-stimulated and bio-augmented treatments had appreciable microbial counts that are higher than that of the untreated. In conclusion, the nutrient-supplement with kenaf-core significantly enhanced microbial growth and activities in the soil, thus improving their ability to biodegrade petroleum hydrocarbons in the polluted soils. Thus, supplementing with Kenaf core to encourage microbiological degradation of petroleum hydrocarbon is recommended.

In Situ Construction of NiCoMn-LDH Derived from Zeolitic Imidazolate Framework on Eggshell-Like Carbon Skeleton for High-Performance Flexible Supercapacitors.

Active compounds based on LDH (ternary layered double hydroxide) are considered the perfect supercapacitor electrode materials on account of their superior electrochemical qualities and distinct structural characteristics, and flexible supercapacitors are an ideal option as an energy source for wearable electronics. However, the prevalent aggregation effect of LDH materials results in significantly compromised actual specific capacitance, which limits its broad practical applications. In this research, a 3D eggshell-like interconnected porous carbon (IPC) framework with confinement and isolation capability is designed and synthesized by using glucose as the carbon source to disperse the LDH active material and enhance the conductivity of the composite material. Second, by constructing NiCoMn-LDH nanocage structure based on ZIF-67 (zeolitic imidazolate framework-67) at the nanometer scale the obtained IPC/NiCoMn-LDH electrode material can expose more active sites, which allows to achieve excellent specific capacitance (2236 F g-1/ 310.6 mAh g-1 at 1 A g-1), good rate as well as the desired cycle stability (85.9% of the initial capacitance upon 5000 cycles test). The constructed IPC/NiCoMn-LDH//IPC ASC (asymmetric supercapacitor) exhibits superior capacitive property (135 F g-1/60.1 mAh g-1 at 0.5 A g-1) as well as desired energy density (40Wh kg-1 at 800W kg-1).