Broad Scenarios Research Articles

A fully integrated breathable haptic textile.

Wearable haptics serve as an enhanced media to connect humans and VR/robots. The inevitable sweating issue in all wearables creates a bottleneck for wearable haptics, as the sweat/moisture accumulated in the skin/device interface can substantially affect feedback accuracy, comfortability, and create hygienic problems. Nowadays, wearable haptics typically gain performance at the cost of sacrificing the breathability, comfort, and biocompatibility. Here, we developed a fully integrated breathable haptic textile (FIBHT) to solve these trade-off issues, where the FIBHT exhibits high-level integration of 128 pixels over the palm, great stretchability of 400%, and superior permeability of over 657 g/m2/day (moisture) and 40 mm/s (air). It is a stand-alone haptic system totally composed of stretchable, breathable, and bioadhesive materials, which empowers it with precise, sweating/movement-insensitive and dynamic feedback, and makes FIBHT powerful for virtual touching in broad scenarios.

Flexible mussel‐inspired hydrogel for transparent wearable strain sensors: Investigation of mechanical, physical properties, self‐healing, and electrical conductivity

AbstractNowadays, flexible hydrogels with electrical conductivity have become extremely helpful with broad application scenarios in electronic membranes in human–machine boundaries. However, a design approach to adjust and ameliorate conductivity, mechanical strength, transparency, self‐healing, and good adhesion remains a challenge. One of these strategies is mussels‐mimicking adhesive hydrogels, presenting strong adhesion. Here, we aim to meet the challenge by pursuing a mussel‐inspired design approach, which leads to the formation of a transparent, self‐healing, adhesive, and electrically conductive hydrogel from dopamine (DA), pyrrole (Py), acrylamide (AM), functionalized iron, and copper ions as an advanced electronic sensor. The transparent hydrogels were prepared using a sonication polymerization method. The results have shown that hydrogels containing copper or iron have conductivity (12 × 10−4 or 27 × 10−4 S/cm), mechanical strength (11.2 or 18.4 kPa), elongation at break (EB: 652.231% or 660.198%) and gauge factors (GF: 3.04679, 2.93513). Also, hydrogels can maintain their conductivity if they are twisted or stretched. Self‐healing behavior, swelling, and water‐induced shape memory effect (SME) due to hydrogen bonds and π–π interactions were observed. The behavior of this hydrogel as wearable sensors in integration with different body tissues such as finger, wrist, breathing, and frown was investigated. The obtained hydrogels showed high sensitivity in different areas of the body, fast response time in the strain range of 0%–%500, and high adhesion and transparency.

X- and gamma rays cross sections and nuclear shielding performance of recycled cathode ray tube doping with high concentrations of Na2CO3

In an attempt to mitigate the increasing number of waste Cathod Ray Tube (CRT) glass in the environment, provide a safe, cheaper, and environmentally attractive recycling route for the glasses, and provide an alternative material for gamma radiation absorption applications, this study investigated the influence of adding Na2CO3 on the density, and gamma photon-absorbing prowess of CRT glass. Using the powder metallurgy process, CRT-NCx glasses consisting of CRT glass powder mixed with two distinct weight concentrations (20% (CRT-NC20 and 40% (CRT-NC40)) of Na2CO3 powder were prepared. The mass attenuation coefficients (μρ) of the prepared glasses were obtained using FLUKA simulations for 15 keV–15 MeV photons. The density of CRT, CRT-NC20, and CRT-NC40 were 3.117 g/cm3, 2.987 g/cm3, and 2.894 g/cm3, respectively. The range of μρ for CRT, CRT-NC20, and CRT-NC40 corresponded to 0.0326–45.5236 cm2/g, 0.030–35.0662 cm2/g, and 0.0278–26.9813 cm2/g, respectively. The half-value layer and mean free path was found to vary within the range 0.005–6.822 cm and 0.007–9.842 cm for CRT; 0.007–7.748 cm and 0.010–11.178 cm for CRT-NC20; and 0.009–8.633 cm and 0.013–12.455 cm for CRT-NC40. The minimum and maximum values of μenρ were 0.0216 and 37.7566 cm2/g for CRT, 0.0202 and 29.1167 cm2/g for CRT-NC20, and 0.01921 and 22.4430 cm2/g for CRT-NC40. CRT-rich glass showed higher radiation absorbed doses for the same beam energy and glass thickness. Na2CO3-rich glasses had lower buildup factors BFs, hence preferable in broad beam transmission scenarios. The investigated CRT-NCx glasses are more attractive for radiation protection functions in contrast to some well-known radiation shielding materials considering their lower mean free paths. The present glass system provides and alternative and effective gamma radiation shield, and also proffers a way of upcycling waste CRT glasses.

Numerical solutions to Hyperbolic Maxwell quasi-variational inequalities in Bean–Kim model for type-II superconductivity

This paper is devoted to the finite element analysis for the Bean–Kim model governed by the full 3D Maxwell equations. Describing type-II superconductivity at the macroscopic level, this model leads to a challenging coupled system consisting of the Faraday equation and a hyperbolic quasi-variational inequality (QVI) of the second kind with L1-type nonlinearity, that arises explicitly from the magnetic field dependency in the critical current. With the involved Maxwell coupling in the 3D H(curl)-setting, the hyperbolic QVI character poses the primary challenge in the numerical investigation. Two mixed finite element methods based on implicit Euler and leapfrog time-stepping are proposed. On the one hand, the implicit Euler method results in a nonstandard system of curl-curl elliptic QVI with a first-order curl-type nonlinearity. Though the well-posedness of this system is guaranteed, its numerical realization is not straightforward and requires the use of a two-stage iteration process of high computational complexity. On the other hand, by approximating the electric and magnetic fields at two different time step levels, the leapfrog method turns out to be more suitable as it naturally eliminates the notorious QVI structure. More importantly, utilizing suited subdifferential and optimization techniques, we are able to prove an efficiently computable explicit formula for its exact solution in terms of the electric field, which makes its numerical computation substantially more favorable than the Euler method. As further advantages, the leapfrog method applies to broad scenarios involving low regular data of bounded variation (BV) in time for both the applied current source and the temperature distribution. Through nonstandard technical arguments tailored to the BV data, our analysis proves the conditional stability and, eventually, the uniform convergence of the proposed leapfrog method. This paper is closed by 3D numerical tests showcasing the reasonable and efficient performance of the proposed numerical solution.

Activating Adsorption Sites of Waste Crayfish Shells via Chemical Decalcification for Efficient Capturing of Nanoplastics.

The property of being stubborn and degradation resistant makes nanoplastic (NP) pollution a long-standing remaining challenge. Here, we apply a designed top-down strategy to leverage the natural hierarchical structure of waste crayfish shells with exposed functional groups for efficient NP capture. The crayfish shell-based organic skeleton with improved flexibility, strength (14.37 to 60.13 MPa), and toughness (24.61 to 278.98 MJ m-3) was prepared by purposefully removing the inorganic components of crayfish shells through a simple two-step acid-alkali treatment. Due to the activated functional groups (e.g., -NH2, -CONH-, and -OH) and ordered architectures with macropores and nanofibers, this porous crayfish shell exhibited effective removal capability of NPs (72.92 mg g-1) by physical interception and hydrogen bond/electrostatic interactions. Moreover, the sustainability and stability of this porous crayfish shell were demonstrated by the maintained high-capture performance after five cycles. Finally, we provided a postprocessing approach that could convert both porous crayfish shell and NPs into a tough flat sheet. Thus, our feasible top-down engineering strategy combined with promising posttreatment is a powerful contender for a recycling approach with broad application scenarios and clear economic advantages for simultaneously addressing both waste biomass and NP pollutants.

Extreme wave impacts on a suspended box above free surface

A systematic approach incorporating precision-controlled experiments and high-fidelity numerical simulations has been employed to delve deeper into the physics of extreme wave impact pressures. Using a suite of high-speed imaging and high-resolution pressure sensing techniques that are accurately synchronized with the wave generation, a consistent and well-correlated set of data providing details of the focusing incident wave front, flow velocities, and impact pressure time histories has been successfully obtained. The numerical simulations using a validated incompressible smoothed particle hydrodynamics (ISPH) provided further details that were not tractable in the experiments. Based on the results obtained, there were five broad impact scenarios identified, ranging from focusing crest impacts to plunging jet impacts with varying entrapped air. Among these impact types, the highest impact pressures were those associated with a focusing wave crest. It has been found that high impact pressures were correlated with a convergence of the horizontally impinging overturning crest and the vertical surge of the wall boundary water mass, but with the overturning crest impingement just ahead of the arrival of the wall boundary water mass, which in essence amounted to the impingement of a focusing wave front. Depending on the relative arrival times of the impinging crest and the wall boundary upsurge, the impact scenarios could vary from an up-slosh to a jet impingement with a clear entrapped air pocket, followed by a flip-through of the incident crest. For the scenario with the highest impact pressures, broadly classified as type II impact in this paper, the peak pressures could reach as high as 85ρC2, an order of magnitude higher than impact scenarios without the focusing effect, such as the scenario with a plunging jet impact with entrapped air (classified as types III and IV impact in this study). As the volume of entrapped air for this scenario was relatively small, the one-phase ISPH model used in this study was able to capture the peak pressure characteristics, including the peak pressure amplitudes. However, in scenarios with significantly highly entrapped air during impact, a two-phase model would be necessary.

A multifunctional flexible composite phase-change film with excellent solar driven thermal management

The development of multifunctional films with integrated temperature regulation, photothermal conversion, and bendability is urgently needed for personal thermal management products. In this paper, aminated multi-walled carbon nanotubes modified phase-change microcapsules (ACNTs-PCMC) were synthesized. Subsequently, a flexible polyvinyl alcohol (PVA)/graphene/ACNTs-PCMC composite film (PGAMF) with a three-dimensional sandwich structure was prepared by a simple tape-casting method. The obtained PGAMF films possessed a phase-change enthalpy of 45.5 ± 0.7 J/g. The designed sandwich structure can fix the ACNTs-PCMC microcapsules inside the PGAMF films through the bonding effect of the PVA to prevent them from falling off and sliding, so that the PGAMF composite films have the proper mechanical properties and excellent flexibility. More importantly, the PGAMF composite films had a high photothermal conversion efficiency of 88.8 %. In the cold environment, the center temperature of the PGAMF composite film adhered to the fiber fabric driven by a low solar radiation was 14.5 ± 0.5 °C higher than that of the fiber fabric without the PGAMF composite film. Therefore, the multifunctional composite films with flexibility, heat storage and solar-to-heat conversion prepared in this study have broad application scenarios in heat preservation in low temperature areas and solar-driven thermal management engineering.

Design and optimization of a combined supercritical CO2 recompression Brayton/Kalina cycle by using solar energy and LNG cold energy

Solar energy and LNG cold energy have broad application scenarios as two renewable sources, but their complementary potential has not been fully explored. To fill this gap, this paper constructs a novel combined cycle that utilizes solar energy and recovers LNG cold energy to generate power. This combined cycle consists of a supercritical carbon dioxide recompression Brayton cycle, an ammonia-water mixture Kalina cycle, and an LNG cryogenic power system. A systematic evaluation was conducted on the thermodynamics and exergoeconomic of the model, and the simulation results under basic operating conditions show that the first law efficiency, second law efficiency, net power output and total unit cost reach 55.73 %, 47.72 %, 13.709 MW and 27.44 $·GJ−1 respectively. The genetic algorithm and elitist non-dominated sorting genetic algorithm are used to optimize the system performance. By using the parallel direct search method, the maximum first law efficiency, as well as second law efficiency and a minimum total unit cost of 59.45 %, 52.23 % and 24.81 $·GJ−1 are obtained respectively. The optimal first law efficiency, second law efficiency, and total unit cost of the system, which are 53.52 %, 50.33 % and 26.44 $·GJ−1 respectively, are searched simultaneously from the multi-objective optimization results by LINMAP decision-making method. Furthermore, this paper analyzes the exergy flow rate of the system and heat transfer processes of the heat exchangers under optimal operating condition. A total of 23,059.35 kW of LNG cold energy is fully utilized by the system in the LNG gasification process. The exergy loss ratio and cost ratio of each equipment analysis demonstrates that the heat exchangers (HX) have the largest percentage both exergy loss ratio and cost ratio, especially the HX4.

Gamma attenuation, dose rate and exposure/absorption buildup factors of apatite–wollastonite (AW) ceramic system

Apatite-wollastonite (AW) is an important biomaterial useful in clinical practice for tissue engineering and other applications. In this research paper, AW and B2O3-doped AW glass ceramics (GCs) were reported and investigated deeply by means of their ability to attenuate gamma-photons. The studied samples denoted by AW, AW-10B, and AW-20B as the B2O3 content from 0 to 20 mol% with the step of 10. Using FLUKA and other theoretical approaches, photon interaction parameters for narrow and broad beam transmission through the AW GCs were estimated for the 15 keV–15 MeV energy range. Also, the density of the GCs increased as the B2O3 content increased. The mass attenuation coefficients were found to be within the ranges 0.0231–13.5659 cm2/g, 0.0225–12.3561 cm2/g, and 0.0220–11.1079 cm2/g for AW, AW-10B, and AW-20B, respectively. The effective atomic number of the GCs fell within the range 11.04–17.26, 10.88–17.01, and 10.21–16.72, respectively. As the doping concentration of B2O3 increased, the gamma energy that the AW GCs were able to absorb decreased. The addition of B2O3 compromised the photon shielding competence of AW in both narrow beam and broad beam scenarios. The GCs had better photon-absorbing competence than some existing gamma-photon shields. The GCs may thus be used as photon absorbers in clinical practice or in other nuclear applications.

Leaping Supercapacitor Performance via a Flash-Enabled Graphene Photothermal Coating.

Elevating the working temperature delivers a simple and universal approach to enhance the energy storage performances of supercapacitors owing to the fundamental improvements in ion transportation kinetics. Among all heating methods, introducing green and sustainable photothermal heating on supercapacitors (SCs) is highly desired yet remains an open challenge, especially for developing an efficient and universal photothermal heating strategy that can be generally applied to arbitrary SC devices. Flash-enabled graphene (FG) absorbers are produced through a simple and facile flash reduction process, which can be coated on the surface of any SC devices to lift their working temperature via a photothermal effect, thus, improving their overall performance, including both power and energy densities. With the systematic temperature-dependent investigation and the in-depth numerical simulation of SC performances, an evident enhancement in capacitance up to 65% can be achieved in photothermally enhanced SC coin cell devices with FG photo-absorbers. This simple, practical, and universal enhancement strategy provides a novel insight into boosting SC performances without bringing complexity in electrode fabrication/optimization. Also, it sheds light on the highly efficient utilization of green and renewable photothermal energies for broad application scenarios, especially for energy storage devices.

Carbon modification facilitates piezocatalytic H2O2 production over BiOCl nanosheets: Correlation between piezoresponse and surface reaction

Piezocatalysis offers a facile approach for the production of H2O2, which is a green fuel and oxidant with broad application scenarios. Clarifying the role of various factors is critical to the rational design of the piezocatalytic system. Herein, carbon species are modified over BiOCl nanosheets, achieving a piezocatalytic H2O2 production rate of 2110 µmol g−1 h−1 in pure water. Mechanistic studies reveal that although the modification weakens the piezoelectricity of BiOCl, the contribution of carbon species in raising the carrier density and serving as the O2 activation sites promotes H2O2 generation. As a result, the decline of piezoresponse is surmounted by the improvement in surface reaction, and the piezocatalytic activity of C-BiOCl outperforms the pristine BiOCl nanosheets. This work emphasizes that the surface active site is the bridge connecting piezoelectricity and catalytic efficiency, which puts forward an insightful strategy for the modularization of the piezocatalytic system.

The future(s) of global governance: A scenarios exercise

AbstractPervasive uncertainty has stretched the fabric of global governance to its limit. The shape and form of future global governance is far from clear – yet we need to explore how it may play out, so that we can not only prepare for it but also overcome possible pernicious trajectories. Scenario thinking can be used to rigorously explore different possible outcomes. In this article, we present an exercise applying scenario thinking to global governance. These scenarios should help policymakers to understand which policies may or may not work in the diverse possible futures. They may also help policymakers to consider how their organisation, state, or institution could be affected if the global governance of a specific issue evolves in one direction or another. Civil society members or private companies may want to probe how robust their strategies would be in different global governance configurations. The article synthetically presents key contextual premises and uncertainties which are given as follows: four broad scenarios for the world in 2035; four corresponding scenarios for global governance; and scenarios for the global governance of four macro‐sectors: trade, security, climate change, and finance.

A Transmission Line Defect Detection Method Based on YOLOv7 and Multi-UAV Collaboration Platform

In order to prevent the economic losses caused by large-scale power outages and the life safety losses caused by circuit failures, the main purpose of this paper is to improve the efficiency, accuracy, and reliability of transmission line defect detection, and the main innovation is to propose a transmission line defect detection method based on YOLOv7 and the multi-UAV collaboration platform. First, a novel multi-UAV collaboration platform is proposed, which improved the search range and detection efficiency for defect detection. Second, YOLOv7 is used as a detector for multi-UAV collaboration platform, and several improvements improved the efficiency of defect detection under complex backgrounds. Finally, a complete transmission line defect images dataset is constructed, and the introduction of several defect images such as insulator self-blast and cracked insulators avoids the problem of low application value of single defect detection. The results indicate that the proposed method not only enhances the detection range and efficiency but also improves the detection accuracy. Compared with YOLOv5-S, which has good detection performance, YOLOv7 improves accuracy by 1.2%, recall by 4.3%, and mAP by 4.1%, and YOLOv7-Tiny achieves the fastest speed 1.2 ms and the smallest size 11.7 Mb. Even if the images contain complex backgrounds and noises, a mAP of 0.886 can still be obtained. Therefore, the proposed method provides effective support for transmission line defect detection and has broad application scenarios and development prospects.

Standardizing Breast Adjuvant Radiation Therapy Practices in a Diverse Health System through Development of a Delphi Consensus Supported Clinical Algorithm

Adjuvant radiation therapy (RT) for early breast cancer is a highly effective treatment option. However, the multitude of available techniques backed by strong clinical evidence can result in a lack of consistency in treatment approaches, even within a single healthcare organization. This presents challenges for both providers and patients in making informed decisions. To address this issue, our radiation department, which serves a large and diverse health system, developed a clinical algorithm for adjuvant RT for breast cancer. This algorithm was created to enhance the quality and standardization of care delivered across our network. A modified Delphi technique was used. A panel of eight experienced breast radiation oncologists from our institution was assembled. The panel first identified the common clinical scenarios encountered in treating patients with adjuvant breast RT, and then made recommendations for the primary and alternative approaches for each scenario. NCCN guidelines, ASTRO executive summaries, and published national and international randomized trials were used for reference. In case of disagreements, the final recommendation was reached through a majority vote. The draft algorithm was also shared with medical oncologists, surgeons, and patient advocates to gather their input prior to final approval by the expert panel. Consensus was reached for three broad clinical scenarios for patients who have undergone lumpectomy or mastectomy: Ductal Carcinoma in Situ (DCIS), Invasive Cancer Node Negative (ICN0), and Invasive Cancer Node Positive (ICN+). The panel agreed subdivision of the scenarios into three risk groups (low, intermediate, and high) and three age groups, based on guidelines and consensus statements. For DCIS patients, size, grade, margin status, hormone receptor status, and tumor focality were used for further stratification. For ICN0 patients, HER2 receptor status and lymphovascular space invasion were also included. For ICN+ patients, nodal status (negative versus 1-3 positive nodes versus more than 3 positive nodes) was used for stratification. Additionally, DCIS and ICN0 patients were further divided into age groups. The panel reached consensus recommendations for RT, including whole breast RT, partial breast RT, chest wall RT, regional nodal irradiation, or omission of RT for each sub-group. Clinical trial enrollment was also recommended where appropriate. A breast cancer adjuvant RT algorithm was developed with the aim of standardizing care for patients with breast cancer. Implementation is expected to standardize treatment recommendations in our health system and to streamline the shared decision-making process with patients.

Combining Person-Job Fit, Organizational Commitment and Organizational Citizenship Behavior to Advance Performance

Background and Purpose: Complaints are a consequence in a company and require improvement. With constructive efforts, there will be feedback that leads to the maintenance of the company’s image. This study seeks to examine the effect of person-job fit and organizational commitment on OCB and performance. Design/Methodology/Approach: The object of the research is PLN in the Mahakam sector of East Kalimantan because it considers that the performance of employees so far has not been optimal. Our focused on 65 employees, and the distribution of the sample was based on simple random sampling. The path analysis method simplifies data processing. Informants who were selected and invited to be interviewed were permanent employees on technical duty at the production site, and all of them were male. Results: Referring to observations, we find that person-job fit and organizational commitment have a significant positive effect on OCB. Then, on performance, person-job fit, organizational commitment, and OCB have a significant positive effect. Conclusion: The novelty lies in the development of dimensions or indicators, expanding knowledge relevant to this research topic. Because it limited the interviews in nature, not all respondents reacted optimally to the number of questions asked. Implications: Academic, managerial, and theoretical contributions consider broad scenarios for further study of investigations or comparisons related to efforts to improve employee performance.

Self-Healable PEDOT:PSS-PVA Nanocomposite Hydrogel Strain Sensor for Human Motion Monitoring.

Strain sensors based on conducting polymer hydrogels are considered highly promising candidates for wearable electronic devices. However, existing conducting polymer hydrogels are susceptible to aging, damage, and failure, which can greatly deteriorate the sensing performance of strain sensors based on these substances and the accuracy of data collection under large deformation. Developing conductive polymer hydrogels with concurrent high sensing performance and self-healing capability is a critical yet challenging task to improve the stability and lifetime of strain sensors. Herein, we design a self-healable conducting polymer hydrogel by compositing poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) nanofibers and poly(vinyl alcohol) (PVA) via both physical and chemical crosslinking. This PEDOT:PSS-PVA nanocomposite hydrogel strain sensor displays an excellent strain monitoring range (>200%), low hysteresis (<1.6%), a high gauge factor (GF = 3.18), and outstanding self-healing efficiency (>83.5%). Electronic skins based on such hydrogel strain sensors can perform the accurate monitoring of various physiological signals, including swallowing, finger bending, and knee bending. This work presents a novel conducting polymer hydrogel strain sensor demonstrating both high sensing performance and self-healability, which can satisfy broad application scenarios, such as wearable electronics, health monitoring, etc.

A novel test of gravity via black hole eikonal correspondence

When adopted in black hole spacetimes, geometric-optics approximations imply a mapping between the quasinormal mode (QNM) spectrum of black holes in the eikonal limit and black hole images. In particular, the real part and the imaginary part of eikonal QNM frequencies are associated with the apparent size and the detailed structure of the ring images, respectively. This correspondence could be violated when going beyond general relativity. We propose a novel method to test the eikonal correspondence via the comparison of two sets of observables from a nonrotating black hole, one extracted from QNM spectra and the other from the lensed photon rings on the image plane. Specifically, the photon ring observables robustly capture the information of the black hole spacetime itself regardless of the surrounding emission models. Therefore, the proposed test of eikonal correspondence can be validated in quite broad scenarios.

Scalable and Tunable PEDOT:PSS Emitter for Thermal Camouflage

AbstractMaterials with tunable infrared emissivity are scarce but significant for thermal camouflage. In this study, the optical properties of the conjugated polymer PEDOT:PSS are investigated, and it is found that its infrared emissivity can be facilely modulated by regulating the PSS doping level in PEDOT:PSS, which enables superior thermal camouflage across broad application scenarios with different objects and background temperatures. An effective model with PEDOT particles embedded in the PSS matrix is proposed to elucidate the infrared optical response of PEDOT:PSS thick films. The PEDOT molecules possess strong electromagnetic shielding in the middle‐infrared wavelength range, contributing largely to the metallic infrared optical performance. Moreover, the metallic infrared optical properties of PEDOT:PSS become weaker through increasing the PSS doping level in PEDOT:PSS, resulting in an incredibly large infrared radiation modulation from IR “white” (high reflectivity) to IR “black” (large emissivity ε). Furthermore, the perfect thermal camouflage matched with the environment (εBG ≈75%) can be achieved for the PEDOT:PSS with a large PSS doping level across a wide temperature ranges from 35 to 60 °C. This work not only reveals the IR optical characteristics of PEDOT:PSS via the effective model but also paves the way for scalable thermal camouflage compatible with various application environments.

Pressure and frequency dependence of elastic moduli of fluid‐saturated dual‐porosity rocks

AbstractThe elastic moduli of subsurface rocks saturated with geofluid often depend on the wave frequency and confining pressure due to the wave‐induced fluid flow and their significant intrinsic compressibility. Therefore, the knowledge of the pressure‐dependent dispersion of elastic moduli is usually used in broad practical scenarios such as geofluid discrimination and in situ abnormal pressure detection. We propose a simple dual‐porosity model to describe the pressure and frequency dependence of elastic moduli of fluid‐saturated rocks. First, we follow the idea of the Shapiro dual‐porosity model to yield more accurate formulas for pressure‐dependent stiff porosity and crack porosity. Then the new formulas for stiff and crack porosities are utilized to express the bulk and shear moduli of dry rocks as a function of pressure. Further, the bulk and shear moduli of a modified frame (i.e. a rock skeleton with the dry stiff pores and fluid‐saturated cracks) are formulated with the pressure‐dependent elastic moduli of dry rock. In order to consider the wave energy attenuation induced by fluid in cracks, the frequency‐independent fluid modulus imbedded in the formulas for bulk and shear moduli of a modified frame is replaced with a frequency‐dependent one incorporating the effect of viscoelastic relaxation. The effective bulk and shear moduli of entire fluid‐saturated body can be computed by inserting the pressure‐dependent stiff porosity and elastic moduli of a modified frame into the Gassmann equation. Moreover, appropriate simplification is performed on the central equations in the case of low porosity and weak deformation of stiff pores to yield an approximate model. Modelling results show that the proposed model can reasonably account for the nonlinear variation of bulk and shear moduli with the elevating effective pressure and cautiously predict the wave dispersion and attenuation. We validate our model by comparing the predicted elastic moduli with the corresponding results given by Shapiro model–based equations and with the laboratory measurements of five different fluid‐saturated rock samples.

A Multimodal Data Harness Approach of Mobile Sensors Trajectory Planning for Target Tracking

The future Internet comprising multimodal mobile wireless sensors (MMWSs) dramatically increases the data dimension and complexity compared to the traditional homogeneous networks. It consists of various types of nodes that can be deployed in different spatial domains to form the space, air, ground, and ocean integrated network (SAGOI-Net). A key challenge to IoT with SAGOI-Net is harnessing the real-time data from these sensors to obtain target characteristics and realize target tracking, especially in rough environment with obstacles and enemy threats. In this paper, we propose an approach -fuzzy logic and flocking control under extended kalman filter (EKFFL) to provide sensor nodes trajectory formation. With the tools from control systems and signal processing, this approach improves the commonly-adopted flocking control algorithm and fully employs multi modality of data. Compared with the modified kalman consistency filter (KCF) approach, the proposed EKFFL achieves higher target tracking accuracy with a shorter time period of trajectory formation. The trade-off between the data delay and tracking accuracy is also analysed. Based on its advantages, the EKFFL approach can be applied in broad scenarios, such as unmanned border awareness systems, environmental monitoring and intelligent transportation.