Search

Hydrogen is an ideal energy source and plays an important role in increasingly global energy issues and environmental problems. Liquid hydrogen (LH2) has many advantages over other storage methods, especially in terms of energy density. However, it may cause enormous harm once it leaks accidently. LH2 leakage is a complex multiphase process involving evaporation, condensation, transfer of mass and heat, and dispersion. In order to study LH2 transportation and storage systems safety, a research project has been carried out to develop a 3D numerical model using an open-source CFD code, OpenFoam, for investigating LH2 accidental release scenarios. Since the release of LH2 is a very complex process, our strategy is to study it step by step. Therefore, in this paper we present our research work at the first stage, a dispersion process of room-temperature gaseous hydrogen without multiphase flow. A small-scale hydrogen release conducted by Sandia National Laboratories is simulated. In this experiment, room-temperature gaseous hydrogen is injected upwards into the air from a small hole with a 1.91 mm diameter. The situations of Froude (Fr) number = 99, 152, and 268 are studied, respectively. The behavior of hydrogen at different Fr numbers is discussed. When high-speed hydrogen enters the air, the speed and concentration of hydrogen decrease rapidly. In addition, the greater the speed, the faster it decays. The result shows a close range of hydrogen reach. Details about the numerical model are introduced. The simulation results are used to verify the validity of the developing numerical model for dispersion and mixing of multi-species. The simulated concentrations and velocity distribution are analyzed and compared with experimental data. The simulation shows a good agreement with the data of Sandia National Laboratories. The agreement between experiments and simulations is measured using the Pearson correlation coefficient (>0.98), which indicates excellent consistency. In the next step, we will integrate the multiphase flow and phase change into the current model. The phase change of liquid hydrogen and air will be simulated to study the release of liquid hydrogen. • Using the open-source CFD code OpenFOAM for simulation of hydrogen jet. • A good agreement between the simulations results and experimental data has been found in this paper. • When high-speed hydrogen is injected into the air, both velocity and concentration drop rapidly. • Final concentration is not sensitive to different injection velocity. [ABSTRACT FROM AUTHOR]

The incorporation of a few amount of MnO 2 into 0.88NaNbO 3 -0.12SrTiO 3 lead-free ceramics was found to effectively stabilize the antiferroelectric orthorhombic P phase before its transition into antiferroelectric orthorhombic R phase, consequently featuring completely reversible electric field-induced antiferroelectric-ferroelectric phase transition. Not only reproducible double polarization hysteresis loops but also repeated sprout-like strain-field curves ensure great application potentials in large-displacement lead-free actuators owing to both large repeatedly-utilized strains of ∼0.33% and low driving field of ∼11 kV/mm. Combined results of XPS, Raman spectroscopy and dielectric properties indicate that the stabilized antiferroelectric P phase was closely related to the reduced B-site cation polarizability and oxygen vacancy concentration, while a slight change in antiferrodistortive degree would discourage the P-R phase transition. These results indicate that ionic doping is an alternative method to alter the antiferroelectric P phase stability of NaNbO 3 -based lead-free ceramics by synergistically considering the influencing factors of phase and crystal structure stability. [ABSTRACT FROM AUTHOR]

Butralin is a dinitrobenzene pesticide, has been widely used as a herbicide in many crops. Its high levels of residues threaten the ecological balance and human health. Therefore, establishment of a sensitive monoclonal antibody (mAb) for rapid detection of butralin residues is critical. In this study, special haptens were designed with good preservation of the characteristic structure of target compound. After mice immunization, a highly sensitive monoclonal antibody was produced. The half-maximum inhibitory concentration (IC 50) was 1.936 ng/mL. And we applied it to develop a method of lateral flow immunoassay (LFIA), with vLOD value of the LFIA strip to be 10 ng/mL. In watermelon and pear samples, the cLOD values of the LFIA strip were 0.432 ng/mL and 0.426 ng/mL, respectively. The recoveries of the developed method ranged from 94.4% ± 2.1%–112.1% ± 3.4% and 89% ± 5.4%–103% ± 4.1% in watermelons and pears samples, with a CV of 2.9%–3.4% and 2.2%–5.2%, respectively. The results demonstrated that the developed method showed great prospect in the detection and monitoring of butralin in real food samples. • New haptens of butralin was synthesized successfully. • Based on the anti- butralin monoclonal antibody, the strip assay was established. • The visual detection limit for flumioxazin was 5 ng/mL. • The strip assay can be applied in on-site monitoring of watermelon and pear samples. [ABSTRACT FROM AUTHOR]

Charge recombination occurring inside the tribolayer limits the further improvement of triboelectric nanogenerator (TENG) output. While the doping of ferromagnetic medium in triboelectric materials has been proven effective in boosting the TENG output, its working mechanism in the tribolayer remains to be investigated. Herein, the dual tribolayer synergistic effect is demonstrated as a means of suppressing surface charge recombination, thus achieving a high peak power density of TENG based on a composite film of polymer/nickel nanoparticles. A dual tribolayer model is proposed to reveal the working mechanism of the ferromagnetic medium for suppressing charge recombination in the positive and negative tribolayer. The charge recombination ratio as a standardized assessment method is defined to quantify the surface charge loss. Owing to the dual tribolayer synergistic effect, the optimal TENG exhibits a record-high peak power density of 15.2 W m-2 Hz-1 with the ultra-low charge recombination ratio of 2.1%, representing a remarkable 3100% increase in comparison to pristine TENG in the atmospheric environment. A self-powered sitting posture monitoring system is developed based on the woven structured DT-TENGs benefiting from the dual-tribolayer synergistic effect. This work demonstrates the superior behavior of TENG in generating ultra-high-power output and provides a significant guidance in materials selection. [Display omitted] • The charge recombination ratio is proposed to quantify the surface charge loss. • Doped ferromagnetic NPs assists in suppressing surface charge recombination. • A synergistic effect is found for DT-TENG via ferromagnetic NPs, especially greatly suppressing charge recombination. • A record-high power density of the DT-TENG can reach 15.2 W m-2 Hz-1 by tribolayer modulation. • A self-powered sitting posture monitoring system with a woven structure DT-TENG is designed. [ABSTRACT FROM AUTHOR]

Isofetamid (ISO), a new generation succinate dehydrogenase inhibitor fungicide, finds extensive application in crops to manage diseases associated with gray mold and sclerotinia. For the purpose of ISO level monitoring, a test strip using colloidal gold immunochromatography was devised specifically to detect ISO residues within fruits. The test strip had calculated detection limits of 0.027, 0.066 and 0.028 mg/kg in kiwifruit, grape, and strawberry, respectively. The quantitative detection of ISO could be achieved within 8 min. Kiwifruits, grapes, and strawberries were simultaneously analyzed using the test strip and LC-MS/MS. The obtained findings showed ISO recovery rates spanning 91.7%–110.0%. Furthermore, the LC-MS/MS outcomes concurred notably with the findings from the test strip. Thus, the test strip we developed proves applicable for on-site ISO residue detection in fruits. • A novel hapten was designed by analyzing the chemical structure of isofetamid (ISO). • A monoclonal antibody against ISO was prepared based on ISO-hapten synthesis. • The test strip was designed for ISO rapid detection in kiwifruit, grape, and strawberry. • The results showed that the test strip matched well with LC-MS/MS. [ABSTRACT FROM AUTHOR]

• A novel AMT hapten was designed by adding a carboxyl group with 4-C spacer arms. • The sensitive and specific anti-AMT mAb was prepared based on hapten design. • The immunochromatographic assay was firstly developed for AMT rapid detection. • The established mehod can meet the requirements of MRLs for AMT residues in foods. Amitraz (AMT) is a broad-spectrum formamidine insecticide and acaricide. In this study, we produced an anti-AMT monoclonal antibody (mAb) with high performance. The half-maximal inhibitory concentration of the anti-AMT mAb was 4.418 ng/mL, the cross reactivity with other insecticides was negligible, and an affinity constant was 2.06 × 109 mmol/L. Additionally, we developed an immunochromatographic assay for the rapid detection of AMT residues in oranges, tomatoes, and eggplants. The cut-off values were 2000 μg/kg in oranges and tomato samples and 1000 μg/kg in eggplant samples and the calculated limits of detection were 14.521 μg/kg, 6.281 μg/kg, and 3.518 μg/kg in oranges, tomatoes, and eggplants, respectively, meeting the detection requirements for AMT in fruits and vegetables. The recovery rates ranged between 95.8 % and 105.2 %, consistent with the recovery rates obtained via LC-MS/MS. Our developed immunochromatographic assay can effectively, accurately, and rapidly determine AMT residues in oranges, tomatoes, and eggplants. [ABSTRACT FROM AUTHOR]

Surface charge density regulation has been used for diverse range of applications. As a newly emerged high-efficiency energy converter, triboelectric nanogenerator (TENG) is sensitive to the surface charge density, making triboelectric polymers with high charge density crucial for expanding the range of TENG applications. Direct charge injection is an efficient strategy to boost output performance of TENG. However, it traditionally requires a high voltage (about 10 kV) and an injection period over minutes. The fast (<1 s) and low-voltage (< 3 kV) electron-injection process in this study for a contact-separate nanogenerator yields an output charge density of 252 μC·m−2, which is twice as large as that of the pristine device. The provided strategy can be applied to various polymers, providing opportunities for investigations in multi-science fields, not just limited to TENGs. [Display omitted] • A facile strategy of tunneling electron injection is proposed. • The surface charge density doubled to 252 μC·m-2, surpassing many recent high-performance TENGs. • The tunneling electron injection method exhibits electron injection with a low applied voltage (<3 kV). • This method is applicable to a wide variety of polymers (FEP, PTFE, PI, PET etc.). [ABSTRACT FROM AUTHOR]

Reconstruction of periorbital region defects is thought to be one of the most challenging areas in reconstructive plastic surgery. This paper describes our experiences with the application of retrograde postauricular island flaps in reconstructing periorbital region defects. Between November 2008 and June 2019, 16 patients with periorbital region defects underwent treatment using a retrograde postauricular island flap. The flap is designed with two portions: 1) the pedicle segment only with the superficial temporal fascia and 2) the flap segment in the posterior auricular region with non-hair-bearing full-thickness tissue. Intraoperatively, the vascular networks between the postauricular and the superficial temporal vessels were preserved. The flap was then transferred to the receipt area after passing through a subcutaneous tunnel. The donor site was directly closed in the postauricular sulcus by advancing the posterior scalp flap. All the periorbital region defects were reconstructed in one-stage surgery. All the flaps survived without venous congestion. The size of the harvested flaps varied from 5.0 × 2.5 cm to 7.5 × 5 cm. The colour of the transferred flaps matched the surroundings of the receipt region, and the eyelids functioned well. A retrograde postauricular island flap is a good choice for the reconstruction of periorbital region defects. The flap can be useful for the reconstruction of the periorbital region, since it uses similar colours and textures. In addition, it permits a "one-stage" reconstruction with less conspicuous donor site scars behind the auricle. [ABSTRACT FROM AUTHOR]

As a common class of growth regulators, gibberellins (GAs) are widely used in agricultural production. However, the abuse and misuse of GAs have led to the problem of high residues in crops. The existing detection methods are still mainly instrumental, and rapid and sensitive detection of GAs remains a challenge. In this study, we designed a novel hapten scheme by analyzing the structure of GAs, which enabled the prepared mAb to simultaneously detect common GAs (GA 3 , GA 1 , GA 4 and GA 7) with high sensitivity and homogeneity. Subsequently, a colloidal gold immunochromatographic assay (GICA) for GAs detection was established by combining mAb with synthetic gold nanoparticles, which could simplify the sample pre-treatment step and the calculated limit of detection, visual limit of detection, cut-off values and linear ranges were 0.09 mg/kg, 0.2 mg/kg, 8 mg/kg, 0.13–1.36 mg/kg for rice and 0.11 mg/kg, 0.2 mg/kg, greater than 8 mg/kg, 0.13–2.45 mg/kg for tomatoes. The recovery assays of GA 3 -spiked samples ranged between 95.1% and 105.1%. The results indicate that our developed method can be used for the rapid, sensitive and efficient on-site detection of GAs in food. • A GA 3 -hapten was designed to produce a highly sensitive and versatile mAb. • A visual immuno-sensing platform was developed. • The results showed a visual LOD of 0.2 mg/kg in rice and tomato samples. • No significant difference in recovery rates were seen between GICA and ic-ELISA. [ABSTRACT FROM AUTHOR]