•Hydraulic and mechanical behaviors of fault rocks were studied by thermal-hydraulic-mechanical (THM) coupling tests.•Evolutions of permeability and porosity of fault rocks under ...thermal-hydraulic-mechanical coupling conditions were clarified.•Mechanical response of fault rocks during geothermal resources exploitation were revealed.
The exploitation of hydrothermal geothermal resources (HGR) in fault zone is one of the most promising technical schemes for geothermal energy development. To understand the hydraulic and mechanical behaviors of rock mass in fault zone, a series of thermal-hydraulic-mechanical (THM) coupling tests of fault rocks were conducted, and the influence of the fault gouge content, water temperature, seepage pressure and stress on the permeability, porosity, secant Young's modulus, cohesion and internal friction angle of fault rocks was investigated. The results show the permeability evolution can be divided into four stages: slight decline stage, slight rise stage, steady increase stage and rapid increase stage. The porosity evolution can be classified into two stages: seepage dominant stage and axial compression dominant stage, and the time-varying law of porosity of cemented rock mass are significantly different. With the increase of content of fault gouge, the secant Young's modulus, cohesion and internal friction angle of fault rocks gradually increase; while the temperature has little significance on the three parameters. With the increase of seepage pressure, the secant Young's modulus, cohesion and internal friction angle decrease; while the three parameters increase accordingly with the increase of the axial and confining pressure. The research results enrich the study of THM coupling properties of fault rocks, and provide a theoretical basis for exploiting HGR by fault.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
This paper investigates the dynamic event-triggered L∞ control for switched affine systems under limited communication resources. For switched affine systems, affine terms bring the difficulty on the ...exclusion of triggering Zeno behavior. The proposed dynamic event-triggered mechanism can preclude the occurrence of triggering Zeno behavior even if affine terms and the exogenous disturbance coexist. Moreover, it further reduces the transmission frequency compared with the static version. The switching chattering phenomenon is avoided by the designed sampled-data switching rule. The co-design method of dynamic event-triggered scheme, switching controller and sampled-data switching rule is provided to achieve practical stability and the L∞ performance with respect to the external interference. Tools and techniques of time-dependent Lyapunov function are used to obtain sufficient conditions in terms of linear matrix inequalities. Finally, the effectiveness of the developed results is illustrated by an example.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Improving the digital citizenship of secondary vocational students is critical for cultivating vocational talents in education. It is an inevitable requirement for modernizing vocational education. ...Focusing on social media competence, this study explores possible ways to improve the digital citizenship of secondary vocational students. A total of 469 secondary vocational students in Wuhan city, Hubei province, were investigated using questionnaires. The data analysis shows that the four dimensions of social media competence (technical use, content interpretation, content generation, and anticipatory reflection) significantly predict digital citizenship. On this basis, we propose four paths for improving the digital citizenship of secondary vocational students: creating a suitable environment for secondary vocational students to apply their skills in information technology; enhancing the ability of secondary vocational students to discriminate about information on the Internet; improving students' interpersonal communication ability when dealing with technical support; building an early warning system for secondary vocational students' behavioral perception.
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BFBNIB, NUK, PILJ, SAZU, UL, UM, UPUK
An integrated renewable geothermal-driven multigeneration system is demonstrated in the present evaluation, consisting of a double-flash geothermal unit, a modified dual-pressure organic Rankine ...cycle, a Proton exchange membrane electrolyzer, and a Claude Hydrogen liquefication subsystem. The proposed system is examined from various standpoints, and the performance of the system is quantified through the output parameters. Besides, a case study is performed to evaluate the operation of the system in a specified state. Moreover, a sensitivity analysis is conducted to follow the behavior of the system under different conditions. Furthermore, a multi-objective particle swarm optimization algorithm is employed to define the optimum solutions. The results of the study bring out a total generated cooling load of 2.27 MW, a net output power of 10.48 MW, and a liquefied Hydrogen rate of 37.83 kg/h. Also, exergetic efficiency and exergy destruction rate values of 55.89 % and 9.39 MW are obtained, respectively. The exergoeconomic and exergoenvironmental outputs are discussed through a total cost rate of 482.62 $/h, a payback period of 3.27 years, and a product exergy-related environmental impact rate of 9.84 Pts/h.
•Integrated geothermal-driven multigeneration system with high performance.•Multiple evaluation aspects: energy, exergy, exergoeconomic, and exergoenvironmental.•Optimal solution found using multi-objective particle swarm optimization.•Significant outputs: cooling load, net power, and liquefied Hydrogen production.•Sensitivity analysis to study system behavior under different conditions.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Development of novel activable dual-mode T
/T
-weighted magnetic resonance (MR) contrast agents with the same composition for dynamic precision imaging of tumors has been a challenging task. Here, we ...demonstrated a strategy to prepare clustered Fe
O
nanoparticles (NPs) with redox-responsiveness to tumor microenvironment to achieve switchable T
/T
-weighted dual-mode MR imaging applications. In this study, we first synthesized ultrasmall Fe
O
NPs with an average size of 3.3 nm and an
relaxivity of 4.3 mM
s
, and then cross-linked the single Fe
O
NPs using cystamine dihydrochloride (Cys) to form clustered Fe
O
/Cys NPs. The Fe
O
nanoclusters (NCs) possess desirable colloidal stability, cytocompatibility, high
relaxivity (26.4 mM
s
), and improved cellular uptake efficiency. Importantly, with the redox-responsiveness of the disulfide bond of Cys, the Fe
O
NCs can be dissociated to form single particles under a reducing condition, hence displaying a switchable T
/T
-weighted MR imaging property that can be utilized for dynamic precision imaging of cancer cells
and a subcutaneous tumor model
due to the reductive intracellular environment of cancer cells and the tumor microenvironment. With the tumor reductive microenvironment-mediated switching of T
to T
MR effect and the ultrasmall size of the single particles that can pass through the kidney filter, the developed Fe
O
NCs may be used as a promising switchable T
/T
dual-mode MR contrast agent for precision imaging of different biosystems.
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IJS, KILJ, NUK, PNG, UL, UM
Development of novel activable dual-mode T1/T2-weighted magnetic resonance (MR) contrast agents with the same composition for dynamic precision imaging of tumors has been a challenging task. Here, we ...demonstrated a strategy to prepare clustered Fe3O4 nanoparticles (NPs) with redox-responsiveness to tumor microenvironment to achieve switchable T2/T1-weighted dual-mode MR imaging applications. In this study, we first synthesized ultrasmall Fe3O4 NPs with an average size of 3.3 nm and an r 1 relaxivity of 4.3 mM–1 s–1, and then cross-linked the single Fe3O4 NPs using cystamine dihydrochloride (Cys) to form clustered Fe3O4/Cys NPs. The Fe3O4 nanoclusters (NCs) possess desirable colloidal stability, cytocompatibility, high r 2 relaxivity (26.4 mM–1 s–1), and improved cellular uptake efficiency. Importantly, with the redox-responsiveness of the disulfide bond of Cys, the Fe3O4 NCs can be dissociated to form single particles under a reducing condition, hence displaying a switchable T2/T1-weighted MR imaging property that can be utilized for dynamic precision imaging of cancer cells in vitro and a subcutaneous tumor model in vivo due to the reductive intracellular environment of cancer cells and the tumor microenvironment. With the tumor reductive microenvironment-mediated switching of T2 to T1 MR effect and the ultrasmall size of the single particles that can pass through the kidney filter, the developed Fe3O4 NCs may be used as a promising switchable T2/T1 dual-mode MR contrast agent for precision imaging of different biosystems.
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IJS, KILJ, NUK, PNG, UL, UM
Thermoacoustic instability phenomena often encounter in gas turbine combustors, especially for the premixed combustor design, with many possible detrimental results. As a classical experiment, the ...Rijke tube is the simplest and the most effective illustration to study the thermoacoustic instability. This paper investigates the active control approach of the thermoacoustic instability in a horizontal Rijke tube. What’s more, the radial basis function (RBF) neural network is adopted to estimate the complex unknown continuous nonlinear heat release rate in the Rijke tube. Then, based on the proposed second-order fully actuated system model, the authors present an adaptive neural network controller to guarantee the flow velocity fluctuation and pressure fluctuation to converge to a small region of the origin. Finally, simulation results demonstrate the feasibility of the design method.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
In this article, a flame retardant microcapsule ammonium polyphosphate microencapsulated by polyurea (POAPP) was successfully synthesized by interfacial polymerization method using ammonium ...polyphosphate (APP) as core and polyurea as shell. The microencapsulation is observed by scanning electron microscopy and characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis and hydroscopicity test, which prove the success in synthesizing microencapsulation. When the POAPP is added into rigid polyurethane foam (RPUF), the flame retardant and mechanical properties are investigated using cone calorimeter, limited oxygen index test, and compressive strength test. The PHRR of RPUF‐POAPP20 decreased from 336.52 kW/m2 (Ref. RPUF) to 203.84 kW/m2 and the THR of RPUF‐POAPP20 was only 7.6 MJ/m2, which is 33.9% lower than that of Ref. RPUF. Furthermore, the limiting oxygen index of RPUF‐POAPP20 reaches 24.8%, which increased by 36.3% compared to Ref. RPUF. Whereas the maximum compressive strength of RPUF‐POAPP5 was 7.46 MPa, which is higher than that of RPUF‐APP5.
Ammonium polyphosphate microencapsulated by polyurea.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Online health care services effectively supplement traditional medical treatment. The development of online health care services depends on sustained interactions between health care professionals ...(HCPs) and patients. Therefore, it is necessary to understand the demands and gains of health care stakeholders in HCP-patient online interactions and determine an agenda for future work.
This study aims to present a systematic review of the antecedents and consequences of HCP-patient online interactions. It seeks to reach a better understanding of why HCPs and patients are willing to interact with each other online and what the consequences of HCP-patient online interactions are for health care stakeholders. Based on this, we intend to identify the gaps in existing studies and make recommendations for future research.
In accordance with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, a systematic retrieval was carried out from the Web of Science, PubMed, and Scopus electronic databases. The search results were confined to those papers published in English between January 1, 2000 and June 30, 2018. Selected studies were then evaluated for quality; studies that did not meet quality criteria were excluded from further analysis. Findings of the reviewed studies related to our research questions were extracted and synthesized through inductive thematic analysis.
A total of 8440 records were found after the initial search, 28 papers of which were selected for analysis. Accessibility to HCPs, self-management, and unmet needs were the main triggers for patients to participate in online interaction. For HCPs, patient education, career needs, and self-promotion were the major reasons why they took the online approach. There were several aspects of the consequences of HCP-patient online interactions on health care stakeholders. Consequences for patients included patient empowerment, health promotion, and acquisition of uncertain answers. Consequences for HCPs included social and economic returns, lack of control over their role, and gaining more appointments. HCP-patient online interactions also improved communication efficiency in offline settings and helped managers of online health care settings get a better understanding of patients' needs. Health care stakeholders have also encountered ethical and legal issues during online interaction.
Through a systematic review, we sought out the antecedents and consequences of HCP-patient online interactions to understand the triggers for HCPs and patients to participate and the consequences of participating. Potential future research topics are the influences on the chain of online interaction, specifications and principles of privacy design within online health care settings, and roles that sociodemographic and psychological characteristics play. Longitudinal studies and the adoption of text-mining method are worth encouraging. This paper is expected to contribute to the sustained progress of online health care settings.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
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