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The formation of aggregates was studied in arginine aqueous solutions using light scattering. The main driving force for aggregate formation is hydrogen bonding between the arginine (Arg) amino acids, which is partially verified using density functional theory calculations. The measurement of energy loss during this process, coupled with Cryo-EM morphology data, indicates that these aggregates are in the solid state. The aggregation occurs in two steps, with a liquid intermediate stage. The investigation of the effect of pH and solute concentration on aggregate formation for other amino acid aqueous solutions verifies that aggregate formation is amino-acid specific, while small-sized clusters formed by weak interactions lead to large-sized aggregation. The water structure around amino acid molecules sheds light on the prediction of their aggregate formation. Homochirality is observed in the aggregates; its existence sheds light on the origin of protein homochirality. [ABSTRACT FROM AUTHOR]

In conventional engineering education, issues such as the discrepancy between virtual and real environments, rigid practical operations, lack of reflective support, and a disconnect between online and offline learning prevail. Digital twin technology, with its high fidelity and real-time interaction features, presents an innovative instructional aid for engineering education. This study developed a digital twin learning system to assist instructors in implementing project-based teaching models in landscaping technology courses. To assess the effectiveness of this system, a quasi-experiment was designed. Seventy students from a vocational high school majoring in landscaping technology in China were recruited as participants. These students were divided into two groups, each consisting of 35 students, with the same teaching pace. The experimental group utilized the system to supplement the instructor's teaching of landscaping courses, while the control group received instruction through traditional methods. The experiment lasted for eight weeks, comprising a total of 16 classes. Ultimately, the results indicated that students in the experimental group significantly outperformed those in the control group in critical thinking, cognitive load, learning experience, and academic performance. Additionally, this research examined the acceptance of learners toward using the digital twin learning system and its influencing factors based on the Technology Acceptance Model, aiming to provide insights into enhancing engineering education courses teaching effectiveness and targeted technological development. [ABSTRACT FROM AUTHOR]

BACKGROUND: In order to study the effect of adsorption of surfactant at the two interfacial layers on emulsion stability, the kinetically stable water‐in‐oil‐in‐water (W/O/W) emulsion carriers were prepared using polyglycerol polyricinoleate (PGPR) and gum arabic (GA) as emulsifiers. The relationship between the adsorption of the surfactant and the stability mechanism of the emulsions was elucidated. RESULTS: When the contents of PGPR and GA were low, the interfaces between oil and the inner and outer water phases, respectively, could not be completely covered. However, when the concentration of PGPR was higher than 60 g kg−1, the excess PGPR was adsorbed on the interface between the oil phase and the outer water phase. When the concentration of GA reached 80 g kg−1, more GA was adsorbed to the oil‐in‐water interface. Moreover, the presence of PGPR on the interface could reduce the adsorption capacity of GA. Two types of kinetically stable emulsions were obtained by optimizing the interface composition (60 g kg−1 GA/80 g kg−1 PGPR and 60 g kg−1 PGPR/80 g kg−1 GA). The kinetically stable W/O/W emulsions prepared in this study were successfully used to encapsulate a hydrophilic vitamin (vitamin B12) with an encapsulation efficiency (EE) of 80% and release efficiency (RE) of 95%. The interfacial adsorption GA can accelerate the hydrolysis of fat. CONCLUSION: Overall, this study provides a new strategy for the preparation of W/O/W emulsions, which might be beneficial for application in food, cosmetic, chemical, and pharmaceutical industries. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

This paper studies the problem of robust sliding mode control (SMC) for a class of nonlinear systems subject to actuator failures and disturbances. By employing a novel integral sliding function constructed with an nested sliding mode controller "ν(t)$$ \nu (t) $$," a dual‐layer sliding mode control is established. The first layer is an integral sliding mode generated by the actuator output, the second one is a linear sliding mode generated by "ν(t)$$ \nu (t) $$." Indeed, the linear sliding mode is nested to the integral sliding mode for the system under consideration. Compared with the state‐of‐the‐art integral sliding mode controls (ISMCs), not only the inherent robustness of ISMC is retained, but also the time derivative of integral sliding function in integral sliding motion dynamics can be compensated by "ν(t)$$ \nu (t) $$," so that the robustness of integral sliding motion is further enhanced. Furthermore, due to the generation of the nested linear sliding mode, it decouples the matched integral sliding function time derivative of integral sliding motion dynamics from the mismatched disturbance. This decoupling facilitates the design of "ν(t)$$ \nu (t) $$" through ℋ∞$$ {\mathscr{H}}_{\infty } $$ control theory, then, the closed‐loop systems are ensured to be asymptotically stable with ℋ∞$$ {\mathscr{H}}_{\infty } $$ performance. Lastly, with two classes of barrier functions exploited for the design of sliding mode controllers, both sliding modes cannot be lost for system responses even in the presence of unforeseen actuator failures and disturbances. In simulation, an IEEE 6 bus power system is offered to demonstrate the superiorities of the theoretical results. [ABSTRACT FROM AUTHOR]

This article studies the fault‐tolerant control for linear systems with disturbances through sliding mode scheme. Compared with the existing results, by means of a nonlinear sliding function with an exponential term, a reduced‐order sliding motion can be obtained while the reaching phase of conventional sliding mode control is eliminated. On the other side, with the help of an exponentially decaying barrier Lyapunov functions, a continuous sliding mode algorithm is established. Within the proposed framework, the trajectories of closed‐loop systems can be forced to a prescribed practical sliding surface, and then, both the transient as well as steady‐state performances are guaranteed despite the occurrence of abrupt actuator faults. Under the Lyapunov direct method, a sufficient condition is derived such that the sliding motion is uniformly bounded with time‐varying performance constraints. Finally, an electric amplidyne system is considered to demonstrate the theoretical results. [ABSTRACT FROM AUTHOR]

Summary: This article is concerned with the problem of adaptive sliding mode control for uncertain Takagi–Sugeno fuzzy systems in the presence of actuator faults. In order to accommodate fuzzy systems, a membership function weights dependent sliding function is first given. Compared with the existing linear sliding function based results, a reduced‐order fuzzy sliding motion through parallel distributed compensation structure is obtained, then less conservative results are achieved. By exploiting a restricted potential function, a continuous sliding mode fault‐tolerant control scheme is established. Then the closed‐loop system trajectory is maintained in practical sliding mode with a preset sliding band, which improves the robustness performances of system especially for the occurrence of abrupt actuator faults. Moreover, with the usage of the property of fuzzy product inference engines through equivalence class in set theory, a less conservative stability criterion in terms of linear matrix inequalities is derived to guarantee the uniformly boundedness of the reduced‐order sliding motion. At last, some illustrative examples are offered to validate the effectiveness of our proposal. [ABSTRACT FROM AUTHOR]

The CO2 phase change absorbent, CPCA, as a novel alternative absorbent, has attracted great attention recently. In this work, the CPCAs composed of MDEA/C4–C6 alcohol/H2O were developed by means of the cosolvent effect. The cosolvent effect of MDEA on the solubility of C4–C6 alcohols in H2O was verified. The CPCAs composed of MDEA/1-butanol/H2O were further examined including the species distributions, absorption rate, cycling capacity and regenerability. The initial absorption rates of all CPCAs were higher than that of 30% MDEA, and its maximum value was 2.5 times higher. A different behavior was shown for the CPCAs that an increase in the absorption rate was observed for a period of time when the CPCAs became turbid. The optimal CO2 cycling capacity of CPCA was 2.48 mol CO2 kg−1, which was 70% higher compared to 30 wt% MDEA. [ABSTRACT FROM AUTHOR]

We systematically investigated the development of film morphology and crystallinity of methyl-ammonium bismuth (III) iodide (MABiI) through onestep spin-coating on TiO-deposited indium tin oxide (ITO)/glass. The precursor solution concentration and substrate structure have been demonstrated to be critically important in the active-layer evolution of the MABiI-based solar cell. This work successfully improved the cell efficiency to 0.42% (average: 0.38%) with the mesoscopic architecture of ITO/compact-TiO/mesoscopic-TiO (meso-TiO)/MABiI/2,2′,7,7′-tetrakis(N,N-di-4-methoxyphenylamino)-9,9′spiro-bifluorene (spiro-MeOTAD)/MoO/Ag under a precursor concentration of 0.45 M, which provided the probability of further improving the efficiency of the Bi-based lead-free organic-inorganic hybrid solar cells. [ABSTRACT FROM AUTHOR]

Two fluorene derivatives, 2-(1,1′:3′,1″-triphenyl-5′-yl)-9,9-diphenyl-9H-fluorene (TPF) and (9,9-diphenyl-9H-fluoren-2-yl)diphenylphosphine oxide (DFPPO) with wide bandgap and good thermal stability were synthesized. The electron mobility of DFPPO is 5 times higher than that of TPF because of the introduction of the electron-withdrawing diphenylphosphine oxide group. The planar heterojunction organic ultraviolet photodetectors (UVDs) were fabricated by applying TPF or DFPPO as electron acceptor, 2,7-dioctyl[1]benzothieno[3,2-b][1]benzothiophene (C8-BTBT) as donor. The UVDs with structure of ITO/PEDOT:PSS/C8-BTBT/DFPPO/LiF/Al presented higher ultraviolet response compared to the TPF based counterpart. Corresponding dark to light current ratio and higher sensitivity is about 179 and 0.69 mA/W under illumination of 1 mW/cm 2 365 nm UV light and bias of −0.5 V. [ABSTRACT FROM AUTHOR]