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Battery thermal management system (BTMS) is very critical to a high-performance electric vehicle. Compared with other cooling methods, the immersion cooling with heat transfer efficiency has received comprehensive attentions recently, especially that with single-phase insulating oil, since it can not only guarantee the heat transfer efficiency but also simplify the system. This article reviews the latest research progress in oil-immersed BTMS based on single-phase insulating oil. Firstly, the development of insulating oils is introduced, and their basic cooling properties are compared and analyzed. Then, the influences of different factors on the effectiveness of the oil-immersed battery cooling system are analyzed from the aspects of immersion degree, flow channel configuration, thermal property parameters, and others. Finally, challenges with using insulating oil as the immersion cooling medium for lithium batteries (LIBs) are discussed, and potential future research directions are outlined. Ultimately, the insights of this paper will hopefully provide some references for researchers to further develop and design more efficient and reliable BTMSs, thus driving the development of LIBs. [ABSTRACT FROM AUTHOR]

This research presents tensile modulus and strength of flax-glass hybrid FRP (HFRP) flat coupons with different fibre volume fractions and fabric stacking sequences under constant hygrothermal (50 °C and 95% RH) and cyclic weathering (water spray-ultraviolet radiation) environments for six months. Two types of polymer (i.e., epoxy (EP) and polyurethane (PUR)) were employed in HFRP. Fourier transformed infrared spectroscopy (FTIR) was performed to identify the changes in functional groups of flax fibres and polymer matrix after exposures. The glass transition temperature (T g) of polymer matrix was measured by differential scanning calorimetry (DSC), which was used to study the influence of environmental exposure on T g. The 3D diffusion coefficients of EP-based flax FRP and glass FRP laminates were determined based on experimental moisture uptake and Fick's law. A coupled mass diffusion-stress analysis based on finite element (FE) model was conducted to simulate the moisture diffusion and swelling behaviour of HFRP. The results showed that hygrothermal and weathering exposures hardly affected tensile modulus of HFRP regardless of the matrix type. After the environmental exposure, EP-based HFRP experienced lower retention ratio of tensile strength (65.4–88.0%) compared to PUR-based HFRP (80.7–94.1%) because of higher moisture absorption in the EP-based HFRP. The influence of fabric stacking sequence on tensile strength reduction varied with different fibre volume fractions in EP-based HFRP, which was explained by the combined effects of the internal stress and damage propagation at flax-glass interface. [ABSTRACT FROM AUTHOR]

The automatically snow-melting system with the electric heating pipes (AS-EHP) is applied in infrastructures (concrete pavement, parking apron, garage entrances and municipal road) in cold regions to mitigate the accumulated snow problem. In order to reduce the energy consumption (EC) and improve the energy utilization rate (EUR) of AS-EHP, the analysis about EC and EUR is investigated. The melting process of AS-EHP is divided into two phases which include preheating the infrastructures and melting. The influence and sensitivity analysis between the inputs (the pipes' embedded spacing and embedded depth, heating power and wind velocity) and the outputs (EC and EUR) are found and compared in two phases by thermal simulation. The applicability and rationality of the simulation are verified by snow melting experiments. According to the simulation, decreasing embedded spacing and depth in phase 1 and phase 2 could reduce EC and improve EUR. In the two phases, the heating power is suggested to be 100 W/m-140 W/m under the condition that the heating pipe’ embedded spacing is 0.10 m–0.25 m, the depth is 0.06 m–0.12 m, and the wind velocity is 0 m/s–15 m/s. The results and suggestions could be used to efficiently guide the scheme design and operation control of AS-EHP in infrastructures. [ABSTRACT FROM AUTHOR]

• Durability of epoxy and polyurethane bonded timber-HFRP joints was studied. • Effect of various hygrothermal and weathering conditions on bond durability was evaluated. • Effect of various hygrothermal and weathering conditions on glass transition temperature of the adhesive was studied. This paper addressed the flexural behaviour (i.e., maximum load, ductility index, flexural strength and stiffness) of laminated veneer lumber (LVL) beams strengthened by 2-layer flax-glass hybrid fibre reinforced polymer (HFRP) exposed to hygrothermal (50℃ and 95% RH) and weathering (cyclic water spray-ultraviolet radiation) conditions for one month. Effects of environmental exposure and fabric sequences on flexural behaviour of LVL-HFRP beams were studied. LVL-FG and LVL-GF beams (inner plies bonded to LVL were flax and glass fibres, respectively) were tested under four-point bending. Tensile test on HFRP flat coupons was also conducted to provide the tensile parameters of HFRP in LVL-HFRP beams. This study showed that the hygrothermal and weathering exposures reduced the maximum load (by 11.4–32.2%), flexural strength (by 19.1–40.0%) and increased the ductility index (by 18.3–41.7%) of LVL-HFRP beams. The hygrothermal exposure did not affect flexural stiffness. The fabric sequence affected the flexural behaviour of LVL-HFRP beams. LVL-GF beams showed lower maximum load and flexural strength than those of the LVL-FG beams, which was attributed to the HFRP delamination in the LVL-GF beams. A theoretical prediction model for the ultimate bending moments of LVL-HFRP beams was used, and the calculated values showed a good agreement with the experiments. [ABSTRACT FROM AUTHOR]

• The bond between FG-PUR and timber was evaluated through single-lap shear tests. • The LVL-PUR-GF showed higher average shear strength, strain efficiency and fracture energy than the LVL-PUR-FG. • The LVL-PUR-GF had higher strain efficiency and fracture energy than LVL-PUR-GG. • The thermal stability of FG-PUR was higher than FF-PUR by incorporating glass fibres. In this paper, the bond behaviour between timber and flax-glass hybrid fibre reinforced polyurethane polymer (HFRP) joints was investigated. The HFRP and timber (termed as HFPR-timber) joints were bonded by polyurethane adhesive. The influence of fibre layer sequences of HFRP on the shear strength and fracture energy of HFRP-timber joints was investigated with a single-lap shear test. Based on the tensile test results of FRP and combined with results from the single-lap shear test, the strain efficiency of the HFRP-timber bond was also calculated. In addition, Fourier transformed infrared spectroscopy (FTIR) was performed to analyse the surface chemical reaction between polyurethane adhesive and the flax fibre. Thermogravimetric analysis (TGA) was also conducted to evaluate the thermal stability of the HFRP, timber and their joints. Furthermore, scanning electronic microscopy (SEM) was used to study the microstructure of the HFRP-timber joints. The results showed that the fibre sequence in the HFRP affected the bond behaviour between the HFRP and timber remarkably. The highest shear strength, strain efficiency, and fracture energy were obtained, when the glass fibre layer was placed next to the timber substrate. FTIR and SEM studies showed that the flax and glass fibres in the FRP composites were not fully saturated by the polyurethane. The TGA results showed that the combination of glass and flax fibres in HFRP led to a higher thermal stability in comparison to flax FRP alone. [ABSTRACT FROM AUTHOR]

We fabricated the amorphous Ho 0.2 Tm 0.2 Gd 0.2 Co 0.2 Al 0.2 ribbon by melt-spun method and systematically investigated its glass forming ability (GFA) and magnetic properties, especially of the magnetic phase transition (MPT) and magneto-caloric (MC) effect. The melt-spun Ho 0.2 Tm 0.2 Gd 0.2 Co 0.2 Al 0.2 ribbon is found to exhibit a fully amorphous structure and good GFA. The amorphous Ho 0.2 Tm 0.2 Gd 0.2 Co 0.2 Al 0.2 ribbon undergoes a second order type MPT around 32.6 K from ferromagnetic to paramagnetic state. Large reversible low temperature MC effect and good MC performances in the amorphous Ho 0.2 Tm 0.2 Gd 0.2 Co 0.2 Al 0.2 ribbon were realized which was identified by the parameters of magnetic entropy change, temperature-averaged entropy change, and refrigerant capacity. These parameters are are at similarly high level with recently reported low temperature MC materials, making the amorphous Ho 0.2 Tm 0.2 Gd 0.2 Co 0.2 Al 0.2 ribbon also attractive for magnetic cooling. [ABSTRACT FROM AUTHOR]

Highlights • DTS has the potential to be used to detect the cast-in-situ pile integrity. • Fiber arrangement was put forward applied to detecting pile integrity in site. • A calculation model was given about temperature distribution. • A model pile was constructed with the dimensions of 1.5 m × 0.5 m × 0.5 m. Abstract Distributed optical fiber temperature sensing technology has the potential to be used to determine the cast-in-situ pile integrity. This study proposed an arrangement of optical fibers for obtaining the pile integrity in situ, and it provided a calculation model for the temperature distribution. A model pile was constructed with the dimensions of 1.5 m × 0.5 m × 0.5 m. The fibers were implanted parallel to the center axis of the pile with a spacing of 0.04 m. The heat conduction area generated because of the heating of the fiber in the center of the pile was tested. The test results indicated that the heating conduction area was limited for certain heating powers. Furthermore, for the heating conduction area and heating power, care must be taken while arranging the optical fibers in the piles to determine the integrity. [ABSTRACT FROM AUTHOR]

The self-focusing transmissions of light beams in five food dye suspensions including Red 40, Red 2, Red 4, Yellow 6, Blue 1 are studied. We qualitatively analyze the key influencing factors of the self-focusing phenomenon with five widely-used food dyes, including the concentration of suspensions, the input-beam power and the kinds of the food dyes. It is found that, the self-focusing phenomenon is mainly attributed to the shift of focus caused by thermal effects. Particularly, Red 40 presents a best nonlinear performance with a 5 cm self-focusing propagation at the wavelength of 532 nm. The significant difference of the self-focusing effects of the five food dyes are further explained by investigating their optical absorption and optical nonlinearity including nonlinear refractive index and absorption coefficient. It is found that a stronger absorption and nonlinearity, originated from the kinds of the dyes or the concentration of the dyes, leads to a stronger nonlinear self-focusing effect. Our work provides a systematic study on the quantitative analysis of the synthetic food colorants with optical nonlinearity, demonstrating a strong nonlinear self-focusing propagation and high nonlinear refractive index in red 40, red 2, red 4. This may have potential applications in nonlinear optics with soft matters. [ABSTRACT FROM AUTHOR]

Road snow accumulation can lead to severe traffic delays, and commonly used deicing agents may pose potential environmental risks. Electrically heated concrete pavement systems utilizing heating pipe technology offer a safe and environmentally sustainable alternative. The snow-free ratio was frequently used as an evaluation index to evaluate the snow-melting performance in road infrastructure. However, the unique wavy temperature distribution during the snow-melting process of the heating system results in discontinuous melting, making the existing snow-free ratio inadequate for accurately assessing its performance and effectively guiding the operational strategy of the heating system. Therefore, this study analyzed the special temperature distribution and proposed a new calculation method for snow-free ratio based on the average temperature and the temperature non-uniformity coefficient of the pavement surface. First, the effects of factors such as heating pipe spacing, embedded depth, heating power, and wind velocity on average temperature and the temperature non-uniformity coefficient were analyzed using finite element simulation. Prediction models for average temperature and the temperature non-uniformity coefficient were then established and validated using the response surface method and experiments. Subsequently, using average temperature and the temperature non-uniformity coefficient as intermediate variables, a new functional relationship between the snow-free ratio and the four factors was established, allowing for satisfactory snow-melting performance to be achieved by adjusting the relevant factors of the heating system. The results show that the error rate between the proposed new calculation method and simulation results is only 4.44 %. Moreover, it was concluded that adjusting spacing and heating power is the most effective strategy for heating systems to achieve optimal snow-melting performance. • New evaluation method was proposed to evaluate snow-melting performance. • 2D finite element model of EHCPS-HPT was established. • The prediction models of snow-melting performance were proposed. • The snow-melting experiments of EHCPS-HPT were conducted. [ABSTRACT FROM AUTHOR]

To reduce the large amount of carbon emissions generated during concrete production and increase the application of green and sustainable building materials in the engineering field, laminated bamboo is used to replace the core section of concrete-filled steel tubes. The effects of cross-sectional forms and core section types on the failure modes and axial compressive properties of column structures are evaluated. The axial compressive behaviors of 16 bamboo columns, bamboo-steel tube (BST) columns, and concrete-filled steel tube (CFST) columns were compared from the perspectives of strength-to-weight ratio, stiffness, and absorbed energy. The experimental results show that the failure modes of laminated bamboo and concrete-filled steel tube (BCFST) columns are end buckling failure and diagonal shear failure. The axial compressive strength of the BST column increased by 94.49 % due to the restraining effect of the steel tube on the bamboo. The key finding is that the cross-sectional area of the core bamboo is a critical factor affecting the axial compressive strength. The BCFST columns with circular cross-sections show excellent ductility, with higher ductility factors of 111.50 % and 30.24 % than BST and CFST columns, respectively. In addition, laminated bamboo is found to be an excellent energy-absorbing material compared to other materials. Based on the confinement effect of BST columns, a prediction model for the axial compressive strength of BCFST columns is proposed, by which the predicted value shows a good agreement (overall error is less than 10 %) with the experimental results. • Proposed different cross-sectional patterns of laminated bamboo and concrete-filled steel tube column. • Evaluated failure modes, strength-to-weight ratios and ductility of laminated bamboo and concrete-filled steel tube column. • Predictive model for the axial compressive strength of laminated bamboo and concrete-filled steel tube column is presented. [ABSTRACT FROM AUTHOR]

The immersion cooling for lithium-ion batteries based on insulating oil has gained a great deal of interest and research, while most of them still lie in the exploratory phase with numerical and model-scale experimental efforts, and applicable cooling mediums as well as the cooling mechanisms are still inconclusive. In this paper, an oil-immersed cooling system for a battery module is designed to verify the feasibility of natural ester oil by comparing with the currently popular mineral oil. The thermal behaviors of the battery module immersed in static and dynamic insulating oils are discussed. It is found that both mineral oil and natural ester oil can efficiently decrease the battery temperature and limit the temperature difference among the batteries to less than 2 °C. For both insulating oils, the cooling effect increases with increasing liquid flow rate, but this improvement gradually weakens. With increasing Reynolds numbers, the forced convection replaces the natural convection as the dominant mechanism, especially in the natural ester oil-based system where the forced convection dominates even in the entire Re range. The comparative results demonstrate that natural ester oil can serve as a potential candidate for the battery immersion cooling. [ABSTRACT FROM AUTHOR]

The equivalent plasticity strain (EPS) of snow-melting heated pavement concrete that exposed to inner elevated temperatures is analyzed with finite element simulations. An optimal mix proportion of the concrete with high thermal conductivity was obtained through mechanical and thermal experiments, which helps facilitate reducing the damage in snow-melting pavement. A three-dimensional (3D) finite element model is developed based on the concrete damage plastic (CDP) model with parameters. The EPS is considered as the performance evaluation index for damage in snow-melting heated pavement concrete. Based on the results of finite element simulations, the EPS of snow-melting heated pavement concrete that exposed to inner elevated temperatures was analyzed under different pavement structures and external conditions. Furthermore, two EPS prediction models were proposed: the one is for EPS and the inner elevated temperature, the other is for EPS and five key factors. The outputs of 3D finite element simulations were verified by an experiment result. It indicated that numerical results agreed with experimental results very well. A prediction and evaluation method of damage for snow-melting heated pavement concrete was established as well. [ABSTRACT FROM AUTHOR]

Shortest path is a fundamental graph problem with numerous applications. However, the concept of classic shortest path is insufficient. In this paper, we study various concepts of “shortest” path in temporal graphs, called minimum temporal paths. Computing these minimum temporal paths is challenging as subpaths of a “shortest” path may not be “shortest” in a temporal graph. We propose efficient algorithms to compute minimum temporal paths and verified their efficiency using large real-world temporal graphs. [ABSTRACT FROM PUBLISHER]

Low scattering and deep penetration of infrared light in colloidal materials are critical in many biomedical applications. Cu x S nanoparticles (NPs) play an important role on this due to their localized surface plasmonic resonant (LSPR) wavelength located at near infrared (NIR) range. In this work, tunable nonlinear responses of Cu x S NP suspensions are investigated by analyzing self-focusing propagation of infrared light. Cu x S NPs are firstly synthesized by hot-injection method with stoichiometric ratio controlled in range of 1.01 ≤ x ≤ 1.91, realizing an appropriate free hole densities for tuning their LSPR absorption wavelengths from 1170 nm to 1640 nm. Then, by changing concentration and stoichiometric ratio to adjust the polarizability, tunable nonlinear self-focusing effects of NIR light in various Cu x S NP/chloroform suspensions are observed, which are induced by optical nonlinearity of these Cu x S NPs. Particularly, a larger concentration and a lower stoichiometric ratio lead to a stronger nonlinearity, which results from the optical force-mediated dynamics and the LSPR absorption interactions. Our results not only provide new candidates for realizing LSPR nonlinearities and curious nonlinear optical phenomena, but also imply new possible tantalizing biomedical applications of Cu x S NPs such as biomedical imaging and medical diagnosis or therapy. • This study presents that near-infrared (NIR) light within the optical windows of biological tissue can be self-focused in suspensions containing self-doped Cu x S nanoparticles (NPs). • It relies on the optical nonlinearities of Cu x S NPs induced by localized surface plasmonic resonant (LSPR), and a smaller free carrier density to their metallic counterparts such as gold NPs. • Thus, we believe that our study makes a significant contribution to the literature because it provides a new strategy to realize deep penetration of light in biological tissue, which also take the advantage of NIR LSPR absorption of Cu x S NPs in applications such as photoacoustic imaging and photothermal therapy. [ABSTRACT FROM AUTHOR]

Abstract: The Zn/Co/Fe-layered double hydroxide nanowires were synthesized via a reverse microemulsion method by using cetyltrimethyl ammonium bromide (CTAB) /n-hexane/n-hexanol/water as Soft-Template. ZnSO4, CoSO4, Fe2(SO4)3 and urea were used as raw materials. The influence of reaction temperature, time, urea concentration and Cn (molar ratio of cetyltrimethyl ammonium bromide to water) on the structure and morphology of Zn/Co/Fe-layered double hydroxides was investigated. The samples were characterized using Transmission Electron Microscopy (TEM), Inductively Coupled Plasma (ICP), X-ray Diffraction (XRD) and Infrared Absorption Spectrum (IR). The results indicate that higher temperature is beneficial to the formation of layered double hydroxides, but particles apart from nanowires could be produced if temperature is up to 120°C. By varying the temperature, reaction time, urea concentration and Cn, we got the optimum conditions of synthesizing uniform Zn/Co/Fe-layered double hydroxide nanowires: 100°C, more than 12h, Cn: 30–33, urea concentration: 0.3M. [Copyright &y& Elsevier]

This study was focused on extraction, radical scavenging activities, and chemical composition identification of total flavonoids in sunflower (Helianthus annuus L.) receptacles (TFSR). We investigated the optimal extract parameters of TFSR using response surface methodology. The highest yield of TFSR was 1.04% with the ethanol concentration 58%, the material-to-liquid ratio 1:20 (v/w), the extraction time 2.6 h, and the extraction temperature 67 °C. The results of radical scavenging activities showed that ethyl acetate fraction (EAF) was the strongest by using 2-diphenyl-1-picrylhydrazyl (DPPH), 2, 2'-azino-bis (3-ethylbenzo thiazoline-6-sulfonic acid) (ABTS) and iron ion reducing analysis. The EAF had the highest flavonoids contents. Four fractions A, B, C and D were enrichment from EAF by polyamide resin. Fraction B had the highest flavonoids content. Thirteen chemical components of flavonoids in fraction B were first identified by Ultimate 3000 Nano LC System coupled to a Q Exactive HF benchtop Orbitrap mass spectrometer (UHPLC-HRMS/MS). Among of the thirteen chemical components, isoquercetin and daidzein were identified accurately by comparing with standard samples. Radical scavenging analysis showed that isoquercetin and EAF had strong activities. Therefore, sunflower receptacles can be used as a source of natural flavonoids. TFSR as a natural radical scavenger has potential applications in pharmaceutical industry. [ABSTRACT FROM AUTHOR]