Effect of Hydration Heat Inhibitor on Thermal Stress of Hydraulic Structures with Different Thicknesses

Concrete hydration heat inhibitor can inhibit the early hydration reaction of concrete and reduce the initial heat release of concrete. However, there is no in-depth research on the effect of hydration heat inhibitor on hydraulic structures with different thicknesses and constraints. In this paper, numerical simulation is used to study the change of temperature and stress field after adding hydration heat inhibitor by establishing the finite element models of tunnel lining, sluice, and gravity dam. The results show that the effect of the hydration heat inhibitors on reducing the temperature peak is inversely proportional to the thickness of the structure. A formula is put forward to evaluate their relation in this paper. When the thickness of the structure is about 6 m, there is no peak cutting effect. For the stress field, hydration heat inhibitor can greatly reduce the thermal stress of the thin-walled structure and make the structure meet the temperature control requirements; for the medium wall thickness structure, it can reduce the internal tensile stress about 50% and the surface tensile stress about 20%, and other temperature control measures are still needed to ensure that the surface tensile stress of the structure meets the requirements; for hydraulic structures with large volume and thickness, the application effect of the inhibitor has limitations, which can reduce the internal tensile stress about 30%, but the tensile stress in the surface area will increase about 7% due to the increase of the internal and external temperature difference; therefore, other temperature control measures such as arranging cooling water pipe, strengthening surface insulation, and so on are needed to ensure that temperature cracks do not occur. This paper provides references and suggestions for the research and engineering application of hydration heat inhibitor

Finite Element Modelling of a Vibro-Impact Capsule Moving in the Small Intestine

The present work aims to develop a realistic finite element (FE) model to depict the nonlinear dynamics of a vibro-impact capsule moving in the small intestine for capsule endoscopy. The FE model considers both the nonlinear vibro-impact mechanism and the nonlinear viscoelastic deformation of the small intestine with haustral folds. It can provide a realistic prediction of the complex dynamics of the vibro-impact capsule system. In particular, the capsule's dynamics are sensitive to the surface condition of the small intestine, and hence, bifurcation analysis will be conducted to reflect the healthy condition of the small intestine.#N/A#N/

A Review of Point Absorber Wave Energy Converters

There are more than thousands of concepts for harvesting wave energy, and wave energy converters (WECs) are diverse in operating principles, design geometries and deployment manners, leading to misconvergence in WEC technologies. Among numerous WEC devices, the point absorber wave energy converter (PAWEC) concept is one of the simplest, most broad-based and most promising concepts that has been investigated intensively all over the world. However, there are only a few reviews focusing on PAWECs, and the dynamical advancement of PAWECs merits an up-to-date review. This review aims to provide a critical overview of the state of the art in PAWEC development, comparing and contrasting various PAWEC devices and discussing recent research and development efforts and perspectives of PAWECs in terms of prototyping, hydrodynamic modelling, power take-off mechanism and control

Anionic polymerization of p-(2,2′-diphenylethyl)styrene and applications to graft copolymers

Well-controlled anionic polymerization of an initiator-functionalized monomer, p-(2,2′-diphenylethyl)styrene (DPES), was achieved for the first time. The polymerization was performed in a mixed solvent of cyclohexane and tetrahydrofuran (THF) at 40 °C with n-BuLi as initiator. When the volume ratio of cyclohexane to THF was 20, the anionic polymerization of DPES showed living polymerization characteristics, and well-defined block copolymer PDPES-b-PS was successfully synthesized. Furthermore, radical polymerization of methyl methacrylate in the presence of PDPES effectively afforded a graft copolymer composed of a polystyrene backbone and poly(methyl methacrylate) branches. The designation of analogous monomers and polymers was of great significance to synthesize a variety of sophisticated copolymer and functionalize polymer materials

Optimisation Verification for a Millimetre-Scale Vibro-Impact Capsule System

A self-propelled capsule endoscope moving inside patient's gut is a promising means of minimising patient's painful investigation and improve the diagnostic efficiency. This paper presents the study of a millimetre-scale capsule prototype that can be propelled by external magnetic field via vibration and impact, from both mathematical modelling and experiment, showing a high progression speed up to 5.3 mm/s. Good agreement between numerical simulation and experimental investigation demonstrates the feasibility of the proposed driving method for small-bowel capsule endoscopy.#N/A#N/

Effects of Bifidobacterium with the Ability of 2′-Fucosyllactose Utilization on Intestinal Microecology of Mice

In breast milk, 2′-Fucosyllactose (2′FL) is the most abundant breast milk oligosaccharide and can selectively promote the proliferation of bifidobacteria. This study aimed to explore the effect of ifidobacterial with different utilization capacities of 2′FL on the intestinal microecology of mice. Furthermore, the effects of ifidobacterial with different 2′FL utilization capabilities on mice gut microbiota under the competitive pressure of 2′FL as a carbon source were explored. Compared with the control group, 2′FL, Bifidobacterium (B.) bifidum M130R01M51 + 2′FL, B. longum subsp. Longum CCFM752, and CCFM752 + 2′FL treatments significantly decreased the food intake. Moreover, the water intake, body weight, and fecal water content in all groups showed no significant difference compared with the control group. The combination of B. longum subsp. longum CCFM752 and 2′FL can significantly increase the levels of pro-inflammatory and anti-inflammatory factors. B. bifidum M130R01M51 and mixed strains combined with 2′FL significantly increased the contents of acetic acid and isobutyric acid. The results showed that B. bifidum M130R01M51, B. breve FHuNCS6M1, B. longum subsp. longum CCFM752, and B. longum subsp. infantis SDZC2M4 combined with 2′FL significantly increased the species richness of the gut microbiota. Moreover, B. longum subsp. longum CCFM752 and B. longum subsp. infantis SDZC2M4 significantly increased the abundance of Faecalibaculum and Bifidobacterium, respectively. In conclusion, exploring the impact on intestinal microecology can provide theoretical guidance for the development of personalized prebiotics for different bifidobacteria, which has the potential to improve the ecological imbalance of infant gut microbiota

Screening of Microbial Strains Used to Ferment <i>Dendrobium officinale</i> to Produce Polysaccharides, and Investigation of These Polysaccharides’ Skin Care Effects

The microbial fermentation of plants is a promising approach for enhancing the yield of polysaccharides with increased activity. In this study, ten microbial strains, Lactiplantibacillus plantarum CCFM8661, Limosilactobacillus reuteri CCFM8631, Lactobacillus helveticus M10, Lacticaseibacillus rhamnosus CCFM237, Lactilactobacillus sakei GD17-9, Lacticaseibacillus casei CCFM1073, Bacillus subtilis CCFM1162, Bacteroides cellulosilyticus FTJSI-E-2, Bacteroides stercoris FNMHLBEIK-4, and Saccharomyces cerevisiae HN7-A5, were used to ferment Dendrobium officinale. The skin care activity of the resulting polysaccharides (F-DOP) was evaluated in cultured HaCaT and RAW 264.7 cells, and a mouse model. The results indicated that D. officinale medium promoted strain proliferation, and fermentation significantly enhanced polysaccharide yield (up to 1.42 g/L) compared to that without fermentation (0.76 g/L). Moreover, F-DOPs, especially after CCFM8631 fermentation, exhibited an excellent ability to attenuate sodium dodecyl sulfate-induced HaCaT cell injury (from 69.04 to 94.86%) and decrease nitric oxide secretion (from 42.86 to 22.56 μM) in lipopolysaccharide-stimulated RAW 264.7 cells. In vivo, CCFM8631-FDOP reduced the transdermal water loss rate, skin epidermal thickness, and interleukin 6, and enhanced the expression of filaggrin, improving 2,4-dinitrofluorobenzene-induced skin damage. Therefore, considering viable cell counts, polysaccharide yields, and skin care efficacy in vitro and in vivo, CCFM8631 is the most suitable strain to enhance the skin care activity of DOPs and possesses promising potential for applications in the cosmetics industry