Experimental and numerical investigation of bulging behaviour of hyperelastic textured tubes

The inflation and propagation of a localized instability in elastic tubes shares the same mathematical features with a range of other localization problems, including buckling propagation in long metal tubes under external pressure. Recent research into origami-inspired tubular geometries has suggested that geometric texturing is able to significantly improve metal pipe resistance to propagation buckling failures, with an increase in critical and propagation pressures. This paper aims to investigate whether texturing generates a similar improvement in hyperelastic tubes under axial loading and internal pressure, with elastomer origami structures of recent interest for use as soft actuators and robots. A new fabrication method with 3D printed moulds in a dip process was first developed to enable fabrication of textured tube samples. An experimental study was then conducted on inflated smooth and textured latex tubes, with instability formation observed at a 1 ms resolution. Comparative numerical models with a Mooney–Rivlin material were able to provide a good prediction of experimentally-observed behaviours up to and slightly past the critical pressure and bulge formation. A parametric numerical study is then conducted to show that the number of divisions in the axial direction and circumferential direction have no and modest effects on critical pressure, respectively. The experimental and numerical investigations both showed that the critical pressure of the textured tube was increased compared to the smooth tube, however the degree of increase was a modest 8% and so unlikely to be of significant practical benefit. This work can provide reference and guidelines for future investigations of tubular inflatable origami structures

Direct measurement of the Raman enhancement factor of rhodamine 6G on graphene under resonant excitation

Graphene substrates have recently been found to generate Raman enhancement. Systematic studies using different Raman probes have been implemented, but one of the most commonly used Raman probes, rhodamine 6G (R6G), has yielded controversial results for the enhancement effect on graphene. Indeed, the Raman enhancement factor of R6G induced by graphene has never been measured directly under resonant excitation because of the presence of intense fluorescence backgrounds. In this study, a polarization-difference technique is used to suppress the fluorescence background by subtracting two spectra collected using different excitation laser polarizations. As a result, enhancement factors are obtained ranging between 1.7 and 5.6 for the four Raman modes of R6G at 611, 1,183, 1,361, and 1,647 cm[superscript −1] under resonant excitation by a 514.5 nm laser. By comparing these results with the results obtained under non-resonant excitation (632.8 nm) and pre-resonant excitation (593 nm), the enhancement can be attributed to static chemical enhancement (CHEM) and tuning of the molecular resonance. Density functional theory simulations reveal that the orbital energies and densities for R6G are modified by graphene dots.National Natural Science Foundation (China) (Nos. 21233001, 50972001, and 21129001)China. Ministry of Science and Technology (Nos. 2011YQ0301240201 and 2011CB932601)Beijing Natural Science Foundation (No. 2132056

Economic explanation of the three agricultural systems and its enlightenment to China

This paper systematically elaborates the core of the three major systems of agriculture and the implications for China’s construction. Firstly, the research status of the three major agricultural systems is discussed. On the basis of this, the production function is used to analyze the agricultural production system, and it is concluded that the core of the production system lies in the efficiency of input and output, which depends on many factors; The analysis of the agricultural industrial system though compound function shows that the core of the industrial system lies in the integration and development of the rural one, two and three industries; the implicit function is used to analyze the agricultural management system, it is concluded that the core of the management system is to complete the conversion from product to commodity, and to control the price of the element, agricultural product prices and fluctuations in prices. According to the above research conclusions, it summarizes the enlightenment to China to provide theoretical and decision-making basis for the construction and optimization of China’s three major agricultural systems

Power Flow Calculation for Traction Networks under Regenerative Braking Condition Based on Locomotive-Traction Network Coupling

The regenerative braking technology is widely applied in high-speed electric multiple units (EMUs). And the voltage rise problem at end of the traction network would be caused by regenerative braking attracts more and more attention. The arm of this paper is to analyze the power flow calculation for EMUs under regenerative braking condition. Power flow calculation was done for two different EMU operation conditions by using a “locomotive-traction network” coupling model. In this model, a constant power load model on an all-parallel AT network multi-conductor chain circuit model is considerable. The simulation analysis shows that the iterative calculation method used in the present study is characterized by fast convergence and high accuracy, and is suitable to power flow calculation for traction networks under the braking condition and traction condition. It can be used to analyze voltage distribution, and the impact of traction load on power quality of the public power grid, etc. DOI: http://dx.doi.org/10.11591/telkomnika.v11i2.203

Review of damage problems of the soft substrate interlayer film

This paper reviews the research progress of soft substrate interlayer film, including the applications and the preparation methods of the soft substrate interlayer film, the testing means of the films’ structure and composition and the researches of the film damage, especially the dynamic damage. As well as the future research directions and applications are put forward

Identification of Two Vulnerability Features: A New Framework for Electrical Networks Based on the Load Redistribution Mechanism of Complex Networks

This paper proposes a new framework to analyze two vulnerability features, impactability and susceptibility, in electrical networks under deliberate attacks based on complex network theory: these two features are overlooked but vital in vulnerability analyses. To analyze these features, metrics are proposed based on correlation graphs constructed via critical paths, which replace the original physical network. Moreover, we analyze the relationship between the proposed metrics according to degree from the perspective of load redistribution mechanisms by adjusting parameters associated with the metrics, which can change the load redistribution rules. Finally, IEEE 118- and 300-bus systems and a realistic large-scale French grid are used to validate the effectiveness of the proposed metrics

Preparation and stabilization of Pickering emulsions by cationic cellulose nanocrystals synthesized from deep eutectic solvent

Abstract In this work, short rod-like cationic cellulose nanocrystals (AH-CNCs) were prepared by sodium periodate oxidation combined with deep eutectic solvent method. The effects of different content AH-CNCs on the properties of the emulsion were studied. With the increase of AH-CNCs content, the diameter of emulsion droplets decreased and the stabilization time prolonged. The electrostatic attraction between the negative charge accumulated at the oil-water interface and AH-CNCs with positive charge improved the stability of the emulsion. Then, the rheological properties showed the interaction of nanocellulose in the continuous phase increased the viscosity of the emulsion. In addition, the droplet diameter of emulsion of 120 s was smaller at different ultrasonic time, the particle size distribution of emulsion changed from monodisperse to polydisperse with the increase of oil volume, the salt concentration had little effect on the droplet size of emulsion, and the preparation of emulsion under acidic conditions was more stable.Abstract In this work, short rod-like cationic cellulose nanocrystals (AH-CNCs) were prepared by sodium periodate oxidation combined with deep eutectic solvent method. The effects of different content AH-CNCs on the properties of the emulsion were studied. With the increase of AH-CNCs content, the diameter of emulsion droplets decreased and the stabilization time prolonged. The electrostatic attraction between the negative charge accumulated at the oil-water interface and AH-CNCs with positive charge improved the stability of the emulsion. Then, the rheological properties showed the interaction of nanocellulose in the continuous phase increased the viscosity of the emulsion. In addition, the droplet diameter of emulsion of 120 s was smaller at different ultrasonic time, the particle size distribution of emulsion changed from monodisperse to polydisperse with the increase of oil volume, the salt concentration had little effect on the droplet size of emulsion, and the preparation of emulsion under acidic conditions was more stable

Preparation of planar and hydrophobic benzocyclobutene‐based dielectric material from biorenewable rosin

A rosin‐based monomer with thermally crosslinkable benzocyclobutene groups was synthesized in this study. The structure of the monomer was examined using mass spectroscopy, Fourier transform infrared spectroscopy, and nuclear magnetic resonance spectroscopy. An amorphous crosslinked network with dielectric constant of 2.71 and dielectric loss of 0.0012 at 30 MHz was formed when the monomer was polymerized at high temperature (> 200 °C). The polymer film exhibits surface roughness (Ra) of 0.337 nm in a 5.0 × 5.0 μm2 area and the water contact angle of 110°. In addition, results from thermogravimetric analysis indicate that the polymer has T5% = 402 °C, and differential scanning calorimetry measurements show that the glass transition temperature is at least 350 °C. Results from nanoindentation tests show that the hardness and Young’s modulus of the polymer are 0.418 and 4.728 GPa, respectively. These data suggest that this new polymer may have potential applications in electronics and microelectronics. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48831.A new rosin‐based monomer containing bibenzocyclobutene groups was synthesized using dehydroabietic acid as the raw material. The monomer could be converted to crosslinked network via thermally ring‐opening polymerization which exhibited excellent planarity and dielectric properties. These results indicate that the polymer is suitable as encapsulation resin or dielectric material in the field of electronics and microelectronics.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/154646/1/app48831.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154646/2/app48831_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154646/3/app48831-sup-0001-supinfo.pd

Improving Medical Report Generation with Adapter Tuning and Knowledge Enhancement in Vision-Language Foundation Models

Medical report generation demands automatic creation of coherent and precise descriptions for medical images. However, the scarcity of labelled medical image-report pairs poses formidable challenges in developing large-scale neural networks capable of harnessing the potential of artificial intelligence, exemplified by large language models. This study builds upon the state-of-the-art vision-language pre-training and fine-tuning approach, BLIP-2, to customize general large-scale foundation models. Integrating adapter tuning and a medical knowledge enhancement loss, our model significantly improves accuracy and coherence. Validation on the dataset of ImageCLEFmedical 2023 demonstrates our model's prowess, achieving the best-averaged results against several state-of-the-art methods. Significant improvements in ROUGE and CIDEr underscore our method's efficacy, highlighting promising outcomes for the rapid medical-domain adaptation of the vision-language foundation models in addressing challenges posed by data scarcity