This paper proposes a data-driven learning control method for stochastic nonlinear systems under random communication conditions, including data dropouts, communication delays, and packet ...transmission disordering. A renewal mechanism is added to the buffer to regulate the arrived packets, and a recognition mechanism is introduced to the controller for the selection of suitable update packets. Both intermittent and successive update schemes are proposed based on the conventional P-type iterative learning control algorithm, and are shown to converge to the desired input with probability one. The convergence and effectiveness of the proposed algorithms are verified by means of illustrative simulations.
Fly ash is the fine solid particulate residue driven out of the boiler with the flue gases in coal-fired power plants. Now it can be used for making geopolymer which acts as a cement-like product. ...The geopolymer technology provides an alternative good solution to the utilization of fly ash with little negative impact on environment. This review summarizes and examines the scientific advances in the preparation, properties and applications of fly ash-based geopolymer. The production of fly ash-based geopolymer is mainly based on alkali activated geopolymerization which can occur under mild conditions and is considered as a cleaner process due to much lower CO2 emission than that from the production of cement. The geopolymerization can trap and fix the trace toxic metal elements from fly ash or external sources. The Si/Al ratios, the type and the amount of the alkali solution, the temperature, the curing conditions, and the additives are critical factors in a geopolymerization process. The mechanical performances of the fly ash-based geopolymer, including compressive strength, flexural and splitting tensile strength, and durability such as the resistance to chloride, sulfate, acid, thermal, freeze-thaw and efflorescence, are the primary concerns. These properties of fly ash-based geopolymer are inherently dependent upon the chemical composition and chemical bonding and the porosity. The mechanical properties and durability can be improved by fine tuning Si/Al ratios, alkali solutions, curing conditions, and adding slag, fiber, rice husk-bark ash and red mud. Fly ash-based geopolymer is expected to be used as a kind of novel green cement. Fly ash-based geopolymer can be used as a class of materials to adsorb and immobilize toxic or radioactive metals. The factors affecting the performances of fly ash-based geopolymer concrete, in particular aggregate, are discussed. For future studies on fly ash-based geopolymer, further enhancing mechanical performance, scaling up production and exploring new applications are suggested.
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•Fly ash is activated by alkali to form geopolymer and such a process is cleaner.•Slag, rice husk-bark ash, fiber and red mud are added to improve the performance of fly ash-based geopolymer.•Mechanical properties and durability of fly ash-based geopolymer are main concerns.•Fly ash-based geopolymer is used as cement and as fixation materials for toxic metals.•Improving performance, scaling-up production and finding new applications are proposed for future.
Ferroelectric polymers are the most promising electroactive materials with outstanding properties that can be integrated into a variety of flexible electronic devices. Their multifunctional ...capabilities, ability to bend and stretch, ease of processing, chemical stability, and the high biocompatibility of polyvinylidene fluoride (PVDF)‐based polymers make them attractive for applications in flexible memories, energy transducers, and electronic skins. Here, recent advance in the research of PVDF‐based flexible electronic devices is reviewed, including nonvolatile memories, energy‐harvesting devices, and multifunctional portable sensors.
The application of ferroelectric polymers in modern flexible electronics is discussed. PVDF‐based polymers are worth exploring as candidate materials for non‐volatile memory, piezoelectric or pyroelectric sensors, and nano‐generators for energy harvesting and self‐powered electronics.
A light‐activated hypoxia‐responsive conjugated polymer‐based nanocarrier is developed for efficiently producing singlet oxygen (1O2) and inducing hypoxia to promote release of its cargoes in tumor ...cells, leading to enhanced antitumor efficacy. This dual‐responsive nanocarrier provides an innovative design guideline for enhancing traditional photodynamic therapeutic efficacy integrated with a controlled drug‐release modality.
Grafting of C7 from the nonparalyzed to the paralyzed side in patients with arm paralysis resulted in greater improvements in power, spasticity, and function at 12 months than rehabilitation therapy ...alone, and functional connection to the ipsilateral cerebral hemisphere developed.
The degeneration of dopaminergic neurons is a major contributor to the pathogenesis of mid‐brain disorders. Clinically, cell therapeutic solutions, by increasing the neurotransmitter dopamine levels ...in the patients, are hindered by low efficiency and/or side effects. Here, a strategy using electromagnetized nanoparticles to modulate neural plasticity and recover degenerative dopamine neurons in vivo is reported. Remarkably, electromagnetic fields generated by the nanoparticles under ultrasound stimulation modulate intracellular calcium signaling to influence synaptic plasticity and control neural behavior. Dopaminergic neuronal functions are reversed by upregulating the expression tyrosine hydroxylase, thus resulting in ameliorating the neural behavioral disorders in zebrafish. This wireless tool can serve as a viable and safe strategy for the regenerative therapy of the neurodegenerative disorders.
Degeneration of dopaminergic neurons is a most common age‐related disorder in the central nervous system. A break‐through idea using electromagnetized nanoparticles to mediate neural plasticity and recover the functions of degenerative dopaminergic neurons in the midbrain of a Parkinson's disease animal model is conceived. A significant advance in remote and regenerative cell therapy of the neurodegenerative diseases is thus provided.
Neurodegenerative diseases generally result in irreversible neuronal damage and neuronal death. Cell therapy shows promise as a potential treatment for these diseases. However, the therapeutic ...targeted delivery of these cells and the in situ provision of a suitable microenvironment for their differentiation into functional neuronal networks remain challenging. A highly integrated multifunctional soft helical microswimmer featuring targeted neuronal cell delivery, on‐demand localized wireless neuronal electrostimulation, and post‐delivery enzymatic degradation is introduced. The helical soft body of the microswimmer is fabricated by two‐photon lithography of the photocurable gelatin–methacryloyl (GelMA)‐based hydrogel. The helical body is then impregnated with composite multiferroic nanoparticles displaying magnetoelectric features (MENPs). While the soft GelMA hydrogel chassis supports the cell growth, and is degraded by enzymes secreted by cells, the MENPs allow for the magnetic transportation of the bioactive chassis, and act as magnetically mediated electrostimulators of neuron‐like cells. The unique combination of the materials makes these microswimmers highly integrated devices that fulfill several requirements for their future translation to clinical applications, such as cargo delivery, cell stimulation, and biodegradability. The authors envision that these devices will inspire new avenues for targeted cell therapies for traumatic injuries and diseases in the central nervous system.
Biodegradable soft magnetoelectric microswimmers are fabricated using a 3D‐printing technique. These microswimmers can perform targeted delivery of neuron‐like cells and induce neuronal differentiation of these cells under different magnetic stimulation modes. This combinatorial technique is a significant step towards highly integrated microrobots, and may open up new avenues for cell therapies.
The in‐plane seismic performance of cold‐formed steel‐framed gypsum partition walls (hereinafter referred to as partition walls) varies with boundaries provided by surrounding members, causing ...differences in repair time. The studies that explicitly consider the influence of boundary members are limited and remain at the preliminary stage of qualitative analysis. Most existing numerical models used for partition walls also lack the simulation of boundaries. Our study focuses on the influence of vertical boundaries on the seismic performance of partition walls. The damage locations of partition walls with different vertical boundaries were recorded during quasi‐static tests, and the repair time was evaluated. Data collected by potentiometers and an image‐based displacement measurement system quantifies the influence of boundaries on the rigid body motion and deformation in a mechanism. A numerical model incorporating boundaries based on the damage and mechanism was proposed and validated to predict the repair time. The presented results provide a potential solution for improved detailing with consideration on repair.
A method is proposed for evaluating the post‐earthquake condition of steel frame structures based on the coupling coefficient (CC). The CC is an index that reflects the internal force distribution of ...each storey and damage mechanism in frames. It is computed using the drift distribution of the maximum structural response estimated from limited monitoring data and the design drawings of the target structure. Preliminary finite element analyses showed that the CC contains some important information that is not obvious in displacement responses, such as the global and local working modes of the structure. Useful information of this type includes whether the damage to each storey is mainly distributed on the beams or columns. An incremental dynamic analysis with an 18‐storey steel frame tested at the E‐Defense shaking table facility confirmed that the structural condition identified by the CC‐based method corresponds to the damage information reported by visual inspection. The analysis results verify the theory of the CC‐based method and provide limit values for the damage grades of steel frames.
Exposed column base (ECB) connections are widely used in low‐ and mid‐rise steel moment‐resisting frames (MRFs). In this study, we investigated the impact of ECB damage on the overall seismic ...properties of low‐rise MRFs. A novel method was proposed to evaluate the post‐earthquake conditions of steel frame structures based on the coupling coefficient (CC). Using only the strain gauge data of the columns in the bottom storey, a method using a modified CC was adopted to classify the degree of damage by estimating the residual capacity of the MRF and predicting the future seismic response under specific intensity levels of hypothetical earthquakes, considering both the structural and non‐structural components. The limit values of CC were obtained by solving the deduced equations. Finite element analyses were conducted to validate the proposed method. The method was applied for calculating the test data of a four‐storey MRF tested at the E‐Defense shaking table facility. Four loading cases comprising six groups of monitored data in the X‐ and Y‐directions were used in this study. A comprehensive and systematic evaluation result was eventually obtained, and the accuracy of the method was validated.
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