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The new version of the gear accuracy standard GB/T 10095.1—2022 has been released, and the standard of accuracy of rack is written with reference to the gear accuracy standard. The manufacturing technology and the processing accuracy of racks have changed greatly, so the standard of accuracy of rack has been revised. The main differences between the 2022 version of the standard of accuracy of rack and the 1988 version are: terms and symbols; definition of total tooth profile deviation; measurement of the rack pair; adding the parts detection method of flame cutting large modulus racks for lifting and lowering of offshore platforms, as well as five measurement tools that can be used in the production process of racks. Analysis is conducted concerning the added and the revised parts.

The unreasonable use of antibiotics is one of the important causes of antimicrobial resistance (AMR) that poses a huge public health threat. Magnolol is a traditional Chinese medicine exhibiting antibacterial-, antifungal-, anti-inflammatory-, and antioxidant activities. However, it is unclear whether magnolol has an inhibitory effect on mycoplasma. This study found that magnolol showed excellent inhibitory activity against various mycoplasmas. Magnolol showed dose-dependent inhibition of Mycoplasma synoviae growth and biofilm formation in vitro. Magnolol caused severely sunken and wrinkled M. synoviae cell membranes at the minimum inhibitory concentration, and an enlarged cell diameter. The chicken embryo infection model showed that magnolol significantly reduced M. synoviae pathogenicity in vivo. Kyoto Encyclopedia of Genes and Genomes pathway analysis showed that the citrate cycle, glycolysis/gluconeogenesis, and pyruvate metabolism were significantly disturbed at the minimum inhibitory concentration of magnolol. Interestingly, 41% of differential metabolites were in the categories of lipids and lipid-like molecules. Protegenin A was up-regulated 58752-fold after magnolol treatment. It belongs to fatty acyls, and destroys cell membrane integrity and cell activity. Ghosphatidylethanolamine, phosphatidylglycerol, phosphatidic acid, and phosphatidylserine related to membrane maintenance and stress response were widely down-regulated. Collectively, our results illustrate the feasibility of magnolol as a phytochemical compound to treat mycoplasma infection.

BackgroundThere is usually a strong coupling of neutronics-thermal hydraulics (N-TH) fields inside nuclear reactors.PurposeThis study aims to accurately simulate the multi-physics fields in nuclear reactors by developing a three-dimensional N-TH coupling code MORPHY tailored to advanced complex reactors.MethodsFirst of all, a three-dimensional triangular-z nodal variational nodal method (VNM) was employed for neutronics calculation. and the stiffness confinement method (SCM) was used to solve the neutron temporal-spatial equation; thermal hydraulic calculations were based on the one-dimensional multi-channel model and the one-dimensional cylindrical thermal conductivity model. Then, the accuracy of neutron dynamics was verified by TWIGL benchmark, Dodds benchmark, and the typical pressurized water reactor (PWR) benchmark NEACRP. Finally, the effects of different coupling methods and angle discrete orders on the results were analyzed and compared against reference solutions by PARCS.ResultsVerification results of TWIGL benchmark show that the deviation of relative power from the reference results is less than 0.5%. Compared with the results of Dodds benchmark, it verifies the MORPHY code's ability to describe unstructured meshes. The transient coupling calculation capability of MORPHY is verified by NEACRP benchmark.ConclusionsNumerical solutions by MORPHY are in good agreement with reference results of the TWIGL, Dodds and NEACRP benchmark problems. It is concluded that MORPHY can adapt to the transient N-TH coupling analysis of nuclear reactor cores.

The environmental control system in most commercial airliner cabins supplies air from shoulder and ceiling level and exhausts air at floor level on both sides of the cabin walls. The ventilation system mixes air in the cabins to create a relative uniform air temperature distribution which is great for passengers’ thermal comfort. However, the mixing ventilation also enhances airborne contaminant transfer. Many displacement ventilation methods have been proposed to use in aircraft cabins, but the disadvantages of the ventilation approach are usually creating draft on the passengers’ ankles and high air temperature stratification between passengers’ heads and feet. This investigation developed an aisle displacement ventilation (ADV) system which can reduce air temperature stratification effectively without occupying the legroom space under the seats, so it is good for passengers and crew members’ comfort and friendly for luggage storage, in addition, it can also be easily installed in aircraft cabins. By installing the system in a five-row, twin-aisle cabin mockup, our study found that the ADV system can create a low air velocity distribution in the cabin and can maintain an acceptable air temperature stratification without draft. The system created an uprising airflow which can effectively remove airborne contaminant which was generated from index passengers’ respiratory activities. The experimental data were used to validate a computational-fluid-dynamics (CFD) program. The validated CFD program was used to compare the ADV with under-seat displacement ventilation (USDV) and underfloor air distribution (UFAD) system along the aisles. The comparison results show that the ADV had obvious better thermal comfort than the other two systems, and the cabin air quality of the three ventilation systems was similar, all far better than the “perfectly-mixed” ventilated condition.

BackgroundWith the improvement of the understanding of the physical mechanism of neutron transport and the development of high performance computing technology, high-fidelity neutronics calculation has attracted widespread attention worldwide. Both deterministic method and Monte Carlo method are employed by various institutions to achieve high-fidelity goals. NECP-X code uses one-step deterministic method whilst OpenMC uses the Monte Carlo method.PurposeThis study aims to verify the feasibility and accuracy of both NECP-X and OpenMC in modelling high-fidelity reactor cores.MethodsBased on BEAVRS2.0.1 benchmark, two high-fidelity models for pressurized water reactor (PWR), i.e., MODEL 1 consisted of 21 fuel assemblies and MODEL 2 consisted of 193 fuel assemblies, were established. Then, NECP-X (one-step deterministic method) and OpenMC (Monte Carlo method) were respectively adopted in these two high-fidelity models to calculate the effective multiplication factor, the reactor power distribution and the control rod worth of different control rod assemblies inserted in the hot zero power (HZP) condition. Finally, calculated results were compared and analyzed.ResultsUnder the HZP condition, the effective multiplication factor deviation between NECP-X and OpenMC is less than 1.40×10-3. The effective multiplication factor deviation of different control rod assemblies inserted is less than 5.9×10-4, and the deviation of control rod worth is less than 4.9×10-4. The average relative deviations of the reactor power distribution between NECP-X and OpenMC are less than 0.6%.ConclusionsNumerical results calculated by two different codes are in good agreement with each other. The feasibility and accuracy of NECP-X and OpenMC in high-fidelity reactor core modeling are preliminarily verified in this study, which lays a foundation for future applications and improvements.

Prompt prediction of the airborne gaseous pollutant transport is important to design a safe and comfortable air environment in an aircraft cabin. This paper proposes a model based on Markov chain to fulfill the task, in which the gaseous pollutant can be released from a source with an arbitrary profile. The model first obtains the airflow field by CFD to construct a transport probability matrix of the gaseous pollutant, then predicts the concentration field at each time step when an impulse is released at the known source location using the transport probability matrix. Finally, detailed trace of the pollutant released from the source with an arbitrary profile can be reproduced by linear superposition. The above strategy is applied on a two-dimensional aircraft cabin with gaseous pollutant released from one passenger for 2s. Results show that the proposed model is able to correctly predict the gaseous pollutant transport in only a few minutes. More than 90% of the computing time can be saved comparing with that from CFD without sacrificing much accuracy.