Capture Mechanism Research Articles

Structural optimization on the oscillating-array-buoys for energy-capturing enhancement of a novel floating wave energy converter system

With the development of wave energy conversion technology, more and more wave power generation devices begin to appear. However, the wave energy capture efficiencies of proposed wave energy converters (WECs) are generally low, especially in some areas where wave energy resource is not rich. Instead, a solution of array-type WECs bears practical potential to increase the wave energy capturing capacity. In this paper, a novel floating-array-buoys WEC (FABWEC) system is presented as the basic model and the structure of its energy capture mechanism, oscillating-array-buoys, is optimized to improve the wave energy capture efficiency. A mathematical model is developed to calculate the efficiency of buoy capturing wave energy. The simulated FABWEC models of different buoys spacing, buoys placement modes and buoys actuating arm lengths are established and analyzed by the hydrodynamic software to assess the efficiency performances. The optimization model is ultimately obtained by comparing the performances of different models. Furthermore, the physical model experiments are carried out under laboratory conditions to verify the optimization results of simulation. The results show that for the cylindrical oscillating-array-buoys, the wave energy capture efficiency could be effectively improved by increasing the buoys spacing appropriately, placing the buoys vertically and arranging the lengths of buoy actuating arms staggered; The average efficiency of buoys capturing wave energy in a wave period can reach 0.36 according to simulated investigation, which is about 38% higher than that of the basic model; The experimental performances are consistent with the simulation results, and the experimental power output of the optimized model can reach up to 1.64 W. Compared with the basic model, the average power output of the experimental optimized model is improved about 50% and the output curve is more stable. It is significant that the optimization model of array-buoys structure verified by simulation and experimental investigation has been practically applied to the next generation FABWEC system, which provides a beneficial experience for the practical application and efficient operation of wave power generation devices.

A rapid analytics tool to map the effect of rezoning on property values

Cities are continually evolving through adjustments to zonings. The potential to integrate more equitable and effective value capture mechanisms into the rezoning process makes estimation of increases in land value from rezoning of interest to urban planners. The use of Residual Land Valuation (RLV), while accepted practice in development feasibility calculations, tends to be absent from the rezoning process because it is outside the skill set of most planners. Also, RLV has historically been applied to individual land parcels with limited potential for wider estimation of land value, and is generally not embedded in planning tools limiting the potential for value capture mechanisms to be included in the early scenario phases of rezoning decisions. This study addressed these issues. An RLV tool to estimate value uplift from rezoning was developed and embedded into a planning support system called Rapid Analytics Interactive Scenario Explorer (RAISE) to explore densification options associated with transport-oriented development. The co-design of the RLV tool with end-users and its test in a real case scenario in Greater Sydney has demonstrated the potential of RAISE-RLV. Specific advances included development of an algorithmic approach to RLV, that could be automated and applied across multiple parcels of land in rapid response to changing zoning. Second, such calculations were incorporated into a platform compatible with established rezoning decision making processes. The study demonstrated that it is possible to include RLV in a platform that improves users' understanding of the valuation process. The RAISE-RVL approach and tool can make a significant contribution to well-considered urbanisation. In addition, in the current era of tight government budgets, properly informed value capture mechanisms are a promising strategy for funding new infrastructure supporting both urban growth and the broader goals that growth can realise.

Mercury removal from flue gas using UiO-66-type metal-organic frameworks grafted with organic functionalities

UiO-66-type metal-organic frameworks (MOF) grafted with organic functionalities (–Br, –NO2 and –NH2) are introduced to investigate the elemental mercury (Hg0) removal from flue gas, and the effect for adding linkers on Hg0 removal is discussed. Results indicated that added functional groups did not alter the original topology of adsorbents, although their size and morphology varied. Adding –NH2 and –NO2 functional groups was detrimental for the thermal stability of UiO-66 except for -Br functional group, and grafted -Br itself was also stable. The Hg0 removal ability of UiO-66 was not significantly changed by grafting –NH2 and –NO2. The grafted -Br was beneficial for Hg0 capture, and the Hg0 removal performance of UiO-66-Br increased with increasing oxygen content and temperature. Furthermore, the mechanism of Hg0 capture was studied.

Behavior of enrichment and migration path of Cu–Ag–Pd–Bi–Pb in the recovery of waste multilayer ceramic capacitors by eutectic capture of copper

Recycling waste multilayer ceramic capacitors (MLCCs) has attracted much attention owing to its rich metal resource and environment pollution. Existing recycling processes have deficiencies in environmental protection, efficiency and metal purity. Capture technology is promising with advantages of efficient enrichment and less pollution, which was applied to recycle metals in this study. In order to study the mechanism for it, the behavior of enrichment and migration of metals in the recovery of waste MLCCs by eutectic capture of copper was discussed. The recovery rates of Ag, Pd and Bi were 87.53%, 100% and 100%, respectively. Alloy (Cu–Ag–Pd–Bi–Pb) and recyclable slag were obtained. There were three phases of Ag, Cu–Pd and Bi–Pb with the analysis of morphology and composition for the alloy. Then the capture mechanism was revealed. The slag and metal separated due to differences in chemical bonds, surface energy, density and viscosity. The interaction of metals was analyzed through phase diagrams and density functional theory. Pd tended to enter Cu phase. Ag and Cu existed as two phases. Bi and Pb neither entered Ag nor Cu phase based on phase diagrams and formation energy. This study provides a theoretical basis for the application of capture technology in metal enrichment.

Paddling motion of a free-swimming jellyfish and Lagrangian coherent structure analysis

Swimming and prey capture by prolate and oblate jellyfishes are numerically examined in two-dimensions using multi-relaxation-time lattice Boltzmann (MRT-LB) and immersed boundary (IB) methods. The near-field fluid structure interaction (FSI) and predator-prey interaction mechanisms are revealed via the simulated Eulerian flow characteristics, finite-time Lyapunov exponent (FTLE) field, and Lagrangian coherent structures (LCS). We implement appropriate periodic body force (Fb) distribution at nodal points of the elastic bell in radial direction to model the paddled swimming as well as complex feeding behavior. For a paddling jellyfish the evolved starting and stopping vortices, as move close to each other in near-wake, create the necessary vortex induced thrust that facilitate the forward body motion. The forced bell contraction in power stroke assists quicker propulsive swimming, whereas passive bell expansion in resting phase facilitates the continued vortex induced forward movement for larger duration, via the refilled fluid momentum. For feeding the detailed prey interception and precise capture areas for various jellyfish models are identified hereby via the computed prey tracks, forward and backward time FTLE fields, and LCS. Swimming performances are analyzed based on interactive thrust and drag forces, input power (energy rate required for bell contraction), output power (thrust multiplied by centroid velocity), and cost of transport (COT). At low Reynolds number (Re) the COT becomes higher for an oblate jellyfish than that of a prolate one; while with increased Re the oblate species appears more economical. However, for enhanced paddling force (Fb) or reduced flapping frequency of bell, the COT for an oblate jellyfish steadily decreases. Hereby impacts of the varied force duration, flapping amplitude, flapping frequency, and bell-elasticity on the swimming are analyzed in greater detail. Notably, the propulsion efficiency increased for higher flapping frequency. The present numerical model efficiently unfolds prey capture mechanisms that are adopted by prolate and oblate medusae and quantifies their success rate (clearance rate, CR) in prey capture. Unlike in past studies, the FTLE fields and LCS that are computed here by tracking the transient motion of a large number of suspended Lagrangian prey particles exhibit the realistic predator-prey interaction and precise prey capture surface, which are difficult to measure or analyze empirically.

Recent progress of green sorbents-based technologies for low concentration CO2 capture

The increased concentration of CO 2 due to continuous breathing and no discharge of human beings in the manned closed space, like spacecraft and submarines, can be a threat to health and safety. Effective removal of low concentration CO 2 from the manned closed space is essential to meet the requirements of long-term space or deep-sea exploration, which is an international frontier and trend. Ionic liquids (ILs), as a widespread and green solvent, already showed its excellent performance on CO 2 capture and absorption, indicating its potential application in low concentration CO 2 capture. In this review, we first summarized the current methods and strategies for direct capture from low concentration CO 2 in both the atmosphere and manned closed spaces. Then, the multi-scale simulation methods of CO 2 capture by ionic liquids are described in detail, including screening ionic liquids by COSMO-RS methods, capture mechanism by density functional theory and molecular dynamics simulation, and absorption process by computational fluid dynamics simulation. Lastly, some typical IL-based green technologies for low concentration CO 2 capture, such as functionalized ILs, co-solvent systems with ILs, and supported materials based on ILs, are introduced, and analyzed the subtle possibility in manned closed spaces. Finally, we look forward to the technology and development of low concentration CO 2 capture, which can meet the needs of human survival in closed space and proposed that supported materials with ionic liquids have great advantages and infinite possibilities in the vital area.

Applying a Sustainable Business Model Lens to Mutual Value Creation With Base of the Pyramid Suppliers

Base of the pyramid (BoP) ventures seek to create “mutual value” for themselves and poor communities, but often use business models unadapted for the BoP context, and have been less successful than hoped. Sustainable business models’ (SBMs) multi-stakeholder lens offers a promising alternative path to mutual value, but BoP-based SBM studies are scarce. This single case study explores whether and how SBM characteristics manifest in the business model and value outcomes of Habi, a Manila footwear company successfully creating mutual value with BoP suppliers. We find SBM characteristics underpin Habi’s dual-structure business model (value chain/shop) and success in four ways: viewing profits as a tool for community development resulted in designing both product and business model around community strengths; understanding communities as systems helped Habi address the complexities of poverty; balancing short-term business needs with a long-term, slow-growth approach led to their choice of investors; and implementing community value capture mechanisms ensured enduring community benefit.

Financing urban infrastructure in India through tax increment financing instruments: A case for smart cities mission

This article is targeted at exploring the Tax Increment Financing (TIF) model for financing planned urban development programs and projects in Indian cities—smart cities, in particular. This is founded on the premise that the TIF approach offers an excellent opportunity to Urban Local Bodies (ULBs) for the creation, capture and recycling of values in cities to support funding of core urban infrastructure in a sustained manner. This article identifies the key components of the TIF model and explains why it is a theoretically elegant and practically desirable strategy for potential acceptance by Indian cities at the present level of urban evolution when municipal finances are unstable and the municipalities are also not in a position to generate current tax income surplus. This article is grounded on the precept of “theory follows practice and vice versa”, case studies on TIF as implemented internationally. In the end, this article suggests directions as to how the TIF principles could be integrated into the theoretical account of financing innovative projects under the Smart Cities Mission, including accessing capital market funds through municipal bonds. The key findings of this article suggest that the efficacy of tax increment financing tools in Indian cities will depend on several factors: the versatility of city development strategy and plan; reforms in municipal finance system; reforms in spatial planning; effective design of TIF projects and financing strategies, including mechanisms for value capture and recycling to catalyze economic growth‐enhancing enterprises that create further values to land‐owners and the city; and human resource capacity to plan, design, finance, implement and monitor projects. If planned well, TIF instruments can act as potent tools to augment external economies of agglomeration and networking and give a momentum to the economic growth, bringing forth a self‐financing or even surplus‐generating process of planned urban expansion, growth and reclamation.

Supply chain finance is not for everyone

PurposeLogistics service providers (LSPs) have unique resources and capabilities that position them to deliver supply chain finance (SCF) solutions. The study aims to discuss and illustrate the necessary resources and process of value creation and capture of LSPs, potentially offering SCF solutions.Design/methodology/approachRelying on a theoretical framework, combining a resource-based view (RBV) with the literature on SCF, the authors apply an abductive case study methodology, including 11 interviews with representatives from four LSPs.FindingsThe main findings are as follow: (1) although an LSP has sufficient resources for value-added SCF solutions, it may not capture enough value to motivate realising them; (2) an LSP considering offering SCF should account for the interaction between its resources and cargo transit times, risk and regulatory restrictions and (3) future studies should distinguish between financing the logistics services and the moved products.Research limitations/implicationsThe authors contribute to the growing field of SCF research by analysing motives and barriers for LSPs to offer SCF service to their customers. Because none of our case companies decided to move beyond experimentation further research is needed on the resources and capabilities needed for LSPs to successfully venture into SCF.Practical implicationsThe study provides LSPs with clear indications of the difficulties involved when contemplating a move into SCF solutions and discusses the potential value of offering such services.Originality/valueDespite evidence of LSPs engaging in SCF in various industries, academic contributions do not go beyond operational conditions or quantification of benefits. The authors add evidence on how LSPs are currently evaluating the prominence of adding SCF to their value offerings, including a new perspective on resources, value generation and capture mechanisms.

Amine-functionalized ionic liquids for CO2 capture.

In petroleum industry, the release of more and more carbon dioxide (CO2) brings greenhouse effect and even results in climate change, leading CO2 capture to become an urgent issue. To design ideal and effective absorbent, interaction mechanism for CO2 capture was systematically investigated in a series of imidazolium-based ionic liquids (ILs). The potential effects of alkyl side chain, electron-philic halogen (F, Cl, Br) atom(s), electron-denoting groups OH and NH2 (bound on cation or/and anion), and water solvent were disclosed on CO2 capture using CAM-B3LYP functional with SMD-GIL solvation model, and the most potential green effective absorbent was predicted. This work provides an explicit idea and theoretical basis about the design of desired IL for CO2 capture. Graphical abstract In present work, no/halogen/amino/hydroxy-functionalized imidazolium tetrafluoroborate ILs were studied for CO2 absorption at the CAM-B3LYP/6-311++G** level of theory by SMD-GIL solvation model. NH2 is more potent group in absorbing CO2 than halogen and OH, and its number is proportional to the adsorption capacity of IL. A potentially high-capacity CO2 absorbent with four NH2 groups was predicted. In addition, the mixture of water could further enhance such chemical absorption by lowering the activation energy barriers and viscosity of IL.

ZnO Nanorod FET Biosensors With Enhanced Sensing Performance: Design Issues for Rational Geometry Selection

ZnO nanorod field effect transistor (FET) biosensors enable ultrasensitive, rapid and label free detection of biomolecules. However, the fabrication of these nanorods without any design guideline results in poor signal to noise ratio, limiting their commercial deployment. The various forces operating within the spacing of the nanorods may prevent complete penetration of the liquid for large aspect ratios and hence mere enhancement of the geometric surface area may not yield the optimum output which indicates the intricacies involved in the design of such sensors. The present work consistently models the analyte and the device regions of the sensor by transforming the understanding of the transduction mechanism of biomolecule capture in nanowire FETs into nanorod FET structure and integrating the spacing dependent liquid penetration depth along with the various temporal fluctuations of the sensor to enhance the signal to noise ratio ( SNR ) and lower the molecule detection limit(MDL). Simulation results, verified experimentally for prostate specific antigen (PSA) shows that the optimal geometry does not correspond to the maximum surface area. Instead it is dependent on the developed surface potentials after receptor immobilization and ligand capture which vary non-monotonically with nanorod radius due to nonlinear dependence of buffer penetration for high aspect ratios. This approach has significantly increased the SNR leading to reliable quantification of PSA in human serum with MDL reduced by almost three orders of magnitude in comparison to recent reports. In summary, this work brings the ZnO nanorod sensors a step closer towards practical application for early diagnosis.

Disentangling the role of surface topography and intrinsic wettability in the prey capture mechanism of Nepenthes pitcher plants

Nepenthes pitcher plants capture prey with leaves specialised as pitfall traps. Insects are trapped when they ‘aquaplane’ on the pitcher rim (peristome), a surface structured with macroscopic and microscopic radial ridges. What is the functional significance of this hierarchical surface topography? Here, we use insect pad friction measurements, photolithography, wetting experiments and physical modelling to demonstrate that the ridges enhance the trap's efficacy by satisfying two functional demands on prey capture: Macroscopic ridges restrict lateral but enhance radial spreading of water, thereby creating continuous slippery tracks which facilitate prey capture when little water is present. Microscopic ridges, in turn, ensure that the water film between insect pad and peristome remains stable, causing insects to aquaplane. In combination, the hierarchical ridge structure hence renders the peristome wettable, and water films continuous, so avoiding the need for a strongly hydrophilic surface chemistry, which would compromise resistance to desiccation and attract detrimental contamination.

The effectiveness of passive land value capture mechanisms in funding infrastructure

PurposeThis study examines the effectiveness of passive value capture mechanisms as an effective form of mechanisms in funding infrastructure from an Australian perspective. The lukewarm response of active value capture mechanisms such as betterment levies in Australia is also discussed.Design/methodology/approachA case study of the Sydney Metro City and Southwest (SMCSW) project in Sydney is used to illustrate passive value capture mechanisms.FindingsUnlike many developed countries, passive value capture mechanisms have been adopted in Australia. This approach is an effective form of value capture mechanisms to capture the value uplift to offset the total development cost of the SMCSW project. However, this approach is highly sensitive to property transaction activities that could be affected by the general economic conditions and unprecedented events such as the COVID-19 pandemic. Further, there is a widespread discussion of the efficiency of land tax in New South Wales (NSW) in capturing all properties subject to the value uplift. Consequently, a shift towards a broad-based land tax is recommended in which it would provide a more efficient way of infrastructure funding.Practical implicationsPolicymakers should consider a broad-based land tax for residential and commercial properties in order to improve the efficiency of passive value capture mechanisms. This also highlights property valuers should play a greater role in the development of broad-based land tax system.Originality/valuePrevious studies have extensively demonstrated property value impacts of transit investments; very little research assesses the growth of value capture funding mechanisms, particularly passive value capture mechanisms. Specifically, this paper is the first paper to assess the effectiveness of passive value capture mechanisms.

Analytical Model for Particle Capture in Nanopores Elucidates Competition among Electrophoresis, Electroosmosis, and Dielectrophoresis.

The interaction between nanoparticles dispersed in a fluid and nanopores is governed by the interplay of hydrodynamical, electrical, and chemical effects. We developed a theory for particle capture in nanopores and derived analytical expressions for the capture rate under the concurrent action of electrical forces, fluid advection, and Brownian motion. Our approach naturally splits the average capture time in two terms, an approaching time due to the migration of particles from the bulk to the pore mouth and an entrance time associated with a free-energy barrier at the pore entrance. Within this theoretical framework, we described the standard experimental condition where a particle concentration is driven into the pore by an applied voltage, with specific focus on different capture mechanisms: under pure electrophoretic force, in the presence of a competition between electrophoresis and electroosmosis, and finally under dielectrophoretic reorientation of dipolar particles. Our theory predicts that dielectrophoresis is able to induce capture for both positive and negative voltages. We performed a dedicated experiment involving a biological nanopore (α-hemolysin) and a rigid dipolar dumbbell (realized with a β-hairpin peptide) that confirms the theoretically proposed capture mechanism.

Capture and release mechanism of La ions by new polyamine-based organoclays: A model system for rare-earths recovery in urban mining process

Uptake and release capability of a new organoclay material were assessed with the final goal to evaluate its applicability in recovering REs from solutions. Capture and release capability have been tested towards a La ions model solution, and interaction mechanism and reactions, active in both capture and release processes, were related to the nature of the organoclay and the operating process parameters. The studied system, polyamine-based organoclay, is able to capture and release La ions with high efficiency. Capture involves three distinct mechanisms: ion exchange reaction with interlayer cations, surface adsorption, and finally, coordination by the polyamine. 2.5 mmol/g of amino-groups in a linear ethylene-amine based organoclay are enough to remove all the lanthanum ions in solution when contacted with containing 0.48 mmol/gclay, i.e. 2600 ppm/clay. 12 coordinating sites are needed for each lanthanum ion. Finally, the organic part of the sorbent solid is highly stable, being unmodified upon many cycles of use.The release step is greatly pH dependent, and the optimised pH is equal to 1. Under these conditions, release efficiencies are always higher than 80 %.Appling multiple steps and intermediate re-basification, very high and reproducible global efficiencies (up to 90 %) are reached.

Above and belowground carbon stock in a tropical forest in Brazil

An increase in atmospheric CO2 levels and global climate changes have led to an increased focus on CO2 capture mechanisms. The in situ quantification and spatial patterns of forest carbon stocks can provide a better picture of the carbon cycle and a deeper understanding of the functions and services of forest ecosystems. This study aimed to determine the aboveground (tree trunks) and belowground (soil and fine roots, at four depths) carbon stocks in a tropical forest in Brazil and to evaluate the spatial patterns of carbon in the three different compartments and in the total stock. Census data from a semideciduous seasonal forest were used to estimate the aboveground carbon stock. The carbon stocks of soil and fine roots were sampled in 52 plots at depths of 0-20, 20-40, 40-60, and 60-80 cm, combined with the measured bulk density. The total estimated carbon stock was 267.52 Mg ha-1, of which 35.23% was in aboveground biomass, 63.22% in soil, and 1.54% in roots. In the soil, a spatial pattern of the carbon stock was repeated at all depths analyzed, with a reduction in the amount of carbon as the depth increased. The carbon stock of the trees followed the same spatial pattern as the soil, indicating a relationship between these variables. In the fine roots, the carbon stock decreased with increasing depth, but the spatial gradient did not follow the same pattern as the soil and trees, which indicated that the root carbon stock was most likely influenced by other factors.

CO2 capture performance and mechanism of blended amine solvents regulated by N-methylcyclohexyamine

Blended amine solvents are considered potential alternatives to monoethanolamine for CO2 capture, for the fast absorption kinetics of primary/secondary amine and low regeneration penalty of tertiary amine. In this research, blended amine solvents comprising N,N-dimethylcyclohexylamine (DMCA) and N-methylcyclohexyamine (MCA) were proposed. CO2 absorption increased the polarity of the products and ensured the absorbent remained homogenous throughout the absorption/desorption cycles. Through quantum chemical calculation, the low stability of MCA-carbamate was confirmed by a ΔΔG3 value of −6.41 kcal/mol, and a possible reaction route from carbamate to bicarbonate was revealed. Thus, the CO2 capacity of DMCA-MCA reached 0.875–0.985 mol CO2/mol amine. Moreover, MCA exhibited considerably low forward energy barrier for zwitterion formation (2.7 kcal/mol), and the CO2 absorption of DMCA could be accelerated through the proton transfer reaction with the MCA-zwitterion. Accordingly, the total mass transfer coefficient of CO2 in DMCA-MCA approached 2.02 × 10−10 mol/cm2 s Pa, which was 1.2-fold higher than that of 5 M MEA. The total regeneration energy of DMCA-MCA blend was estimated at 2.20 GJ/t CO2, which was 44.9% lower than 5 M MEA. This study developed a novel DMCA-MCA blended solvent with rapid absorption rate, huge CO2 capacity and efficient regeneration for CO2 capture.

Elucidation of the Underlying Mechanism of CO2 Capture by Ethylenediamine-Functionalized M2(dobpdc) (M = Mg, Sc-Zn).

We, for the first time, systematically investigated the crystal structures, adsorption properties, and microscopic mechanism of CO2 capture with ethylenediamine (en)-appended isostructural M2(dobpdc) materials (M = Mg, Sc-Zn), using spin polarized density functional theory (DFT) calculations. The binding energies of en range from 142 to 210 kJ/mol. The weakest binding materials are en-Cr2(dobpdc) and en-Cu2(dobpdc). Two typical models, the pair model and the chain model, have been considered for CO2 adsorption. Generally, the chain model is more stable than the pair model. The CO2 adsorption energies of the chain model are in the range of 30-96 kJ/mol, with a strong metal dependence. Among these, the en-Sc2(dobpdc) and en-Cu2(dobpdc) have the highest and lowest CO2 adsorption energies, respectively. Moreover, the dynamic progress of CO2 adsorption has been unveiled via exploration of the full reaction pathway, including transition states and intermediates. First, the CO2 molecule interacts with en-MOFs to form a physisorbed complex with a shallow potential well. This is followed by overcoming a relatively large energy barrier to form a chemisorbed complex. Finally, ammonium carbamate is formed along the one-dimensional channels within the pore with a small energy barrier for configuration transformation. These results agree well with the experimental observations. Understanding the detailed microscopic mechanism of CO2 capture is quite crucial for improving our fundamental knowledge base and potential future applications. This work will improve our understanding of CO2 adsorption with amine functionalized MOFs. We expect our results to stimulate future experimental and theoretical research and advance the development of this field.

Performance Analysis of an Adaptive Bistable Point Absorber Wave Energy Converter Under White Noise Wave Excitation

Performance analysis is conducted for an adaptive bistable point absorber wave energy converter under white noise wave excitation. The adaptive bistable wave power capture mechanism is composed of two oblique springs responsible for bistable characteristics, and two auxiliary springs realizing the ‘adaptive’ feature. White noise wave excitation is adopted to explore the effects of multi-frequency input in absence of different energy distribution characteristics. Time domain simulations are performed based on Cummins equations derived from linear potential flow theory. Results indicate that the adaptive bistable mechanism still bears a better power performance than its linear counterpart which may be well explained by its inherent ‘phase control’ feature in white noise wave excitation. A parametric study is also carried out to investigate how the power capture performance of the adaptive bistable point absorber wave energy converter is affected by main and auxiliary spring stiffness, random phase of wave excitation and power-take-off damping.

Arousal-Biased Competition Explains Reduced Distraction by Reward Cues Under Threat

Anxiety has consistently been found to potentiate the attentional processing of physically salient stimuli. However, a recent study demonstrated that experimentally-inducing anxiety reduces attentional capture by previously reward-associated stimuli, suggesting that anxiety does not globally increase distractibility but rather its influence depends on the nature of the eliciting stimulus. To decipher how the processing of threat interacts with the processing of visual reward cues, we probed the neural mechanisms of oculomotor capture by previously reward-associated stimuli with and without the threat of unpredictable electric shock (blockwise manipulation, within-subjects), combining the value-driven attentional capture paradigm with the translational threat of shock paradigm in an fMRI study. Our eye-movement data replicated prior behavioral findings demonstrating an interaction between threat and distractor condition, with oculomotor capture by previously reward-associated distractors being reduced under threat. In our neuroimaging data, significant main effects of threat and distractor condition on stimulus-evoked blood-oxygen-level-dependent (BOLD) activation were evident in the extrastriate visual cortex, frontal eye field, intraparietal sulcus, and caudate tail, collectively referred to as the value-driven attention network (VDAN). In addition, we found an interaction between distractor condition and threat within each region of the VDAN. Surprisingly, the direction of this interaction was opposite that of the behavioral interaction, with the previously reward-associated distractor evoking especially strong neural activation under threat. Our neuroimaging data are consistent with the Arousal-Biased Competition (ABC) model of information processing in the visual system, although our corresponding behavioral results suggest that, at least under certain circumstances involving reward cues, such biased competition can be leveraged to facilitate more efficient ignoring at the level of eye movements. Our findings inform our understanding of value-driven attention, emotion-attention interactions, and mechanisms of signal suppression.