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Due to the low insertion speed and poor weft motion stability with single round-hole relay nozzle in the air jet loom, this study is aims to investigate the characteristics of transient intersecting airflow from a main nozzle and tri-elliptical hole relay nozzles. The turbulent intersecting airflow was simulated based on a large eddy simulations (LES). The correctness of the LES model was evaluated by comparing the time-averaged axial velocity with experimental and the Reynolds-averaged Navier–Stokes (RANS) results. The LES simulation has shown that only one potential-core arose its height about 4 mm for single round hole relay nozzle, whereas three potential-core arouse its height about 4 mm for tri-elliptical hole relay nozzles. It is possible to enhance the mean axial velocity of the intersecting airflow by up to 10% and decrease fluctuation magnitude by 25% using a new type of tri-elliptical center array relay nozzle. [ABSTRACT FROM AUTHOR]

Knowledge of aerosol radiative effects in the Tibetan Plateau (TP) is limited due to the lack of reliable aerosol optical properties, especially the single scattering albedo (SSA). We firstly reported in situ measurement of SSA in Lhasa using a cavity enhanced albedometer (CEA) at λ = 532 nm from 22nd May to 11th June 2021. Unexpected strong aerosol absorbing ability was observed with an average SSA of 0.69. Based on spectral absorptions measured by Aethalometer (AE33), black carbon (BC) was found to be the dominated absorbing species, accounting for about 83% at λ = 370 nm, followed by primary and secondary brown carbon (BrCpri and BrCsec). The average direct aerosol radiative forcing at the top of atmosphere (DARFTOA) was 2.83 W/m2, indicating aerosol warming effect on the Earth‐atmosphere system. Even though aerosol loading is low, aerosol heating effect plays a significant role on TP warming due to strong absorbing ability. Plain Language Summary: The Tibetan Plateau (TP) has experienced rapid warming over the past decades, but the key factors affecting TP climate change haven't yet been clearly understood. Aerosol single scattering albedo (SSA) is a key optical parameter determining aerosol warming or cooling effect; however, reliable SSA measurement is scarce in TP. This study firstly reported in situ measurement of SSA in Lhasa and explored the direct radiative effect of aerosol on TP warming. Strong aerosol absorption, mainly contributed by black carbon (BC), was observed with an average SSA value of 0.69 in this city. Besides Lhasa, other sites over TP were also reported with low SSA (≤0.77) from surface measurement. The strong aerosol absorption could cause heating effect on the Earth‐atmosphere system. To relieve TP warming, reasonable pollutant emission control strategies should be taken urgently to weaken aerosol absorbing ability. Key Points: Unexpected low aerosol single scattering albedo was observed in Lhasa via in situ measurement of multiple optical parameters simultaneouslyBlack carbon was the dominant contributor (∼83%) to aerosol absorption at 370 nm, followed by primary and secondary brown carbonThe strong absorption in Lhasa exerted positive direct aerosol radiative forcing (warming effect) at the top of atmosphere [ABSTRACT FROM AUTHOR]

Pluripotent stem cell‐derived small extracellular vesicles (PSC‐sEVs) have demonstrated great clinical translational potential in multiple aging‐related degenerative diseases. Characterizing the PSC‐sEVs is crucial for their clinical applications. However, the specific marker pattern of PSC‐sEVs remains unknown. Here, the sEVs derived from two typical types of PSCs including induced pluripotent stem cells (iPSC‐sEVs) and embryonic stem cells (ESC‐sEVs) were analysed using proteomic analysis by liquid chromatography with tandem mass spectrometry (LC‐MS/MS), and surface marker phenotyping analysis by nanoparticle flow cytometry (NanoFCM). A group of pluripotency‐related proteins were found to be enriched in PSC‐sEVs by LC‐MS/MS and then validated by Western Blot analysis. To investigate whether these proteins were specifically expressed in PSC‐sEVs, sEVs derived from seven types of non‐PSCs (non‐PSC‐sEVs) were adopted for analysis. The results showed that PODXL, OCT4, Dnmt3a, and LIN28A were specifically enriched in PSC‐sEVs but not in non‐PSC‐sEVs. Then, commonly used surface antigens for PSC identification (SSEA4, Tra‐1‐60 and Tra‐1‐81) and PODXL were gauged at single‐particle resolution by NanoFCM for surface marker identification. The results showed that the positive rates of PODXL (>50%) and SSEA4 (>70%) in PSC‐sEVs were much higher than those in non‐PSC‐sEVs (<10%). These results were further verified with samples purified by density gradient ultracentrifugation. Taken together, this study for the first time identified a cohort of specific markers for PSC‐sEVs, among which PODXL, OCT4, Dnmt3a and LIN28A can be detected with Western Blot analysis, and PODXL and SSEA4 can be detected with NanoFCM analysis. The application of these specific markers for PSC‐sEVs identification may advance the clinical translation of PSCs‐sEVs. [ABSTRACT FROM AUTHOR]

Location-based services are now playing an integral role in the development of emerging industries, such as the Internet of Things, artificial intelligence and smart cities. Although GPS, Beidou and other satellite positioning technologies are becoming more and more mature, they still have certain limitations. In order to meet the needs of high-precision positioning, wireless positioning is proposed as a supplementary technology to satellite positioning, in which the Received Signal Strength Indication (RSSI) is one of the most popular positioning methods. In this paper, the application scenarios, evaluation methods and related localization methods of wireless positioning based on RSSI are studied. Secondly, the relevant optimization methods are analyzed and compared from different angles, and the methods of RSSI data acquisition are described. Finally, the existing problems and future development trends in RSSI positioning methods are expounded, which has certain reference significance for further research on RSSI localization. [ABSTRACT FROM AUTHOR]

In this paper, a certain type of ammunition bracket was studied, the stress distribution under working load is calculated by static analysis and display dynamic analysis, the stress distribution result show that the maximum load during the working cycle is the instantaneous impact force. Through ANSYS software, Goodman theory method was used to modify the stress, the fatigue life of the bracket and the safety factor of each position of the bracket are calculated. It can provide for life prediction and reliability research of the projectile support.

Hypoxia and adverse health outcomes might be affected by O 3 pollution in the highland city of Lhasa. NO x emissions can amplify the role of volatile organic compounds (VOCs) in the secondary production of O 3 under the conditions of high ultraviolet (UV) radiation levels and unfavourable dispersion patterns in the Lhasa River valley. Here, online C 2 –C 11 VOC measurements, accompanied by other parameters concerning the O 3 chemical budget, were first obtained and employed to identify the key VOC species and key sources of VOCs in terms of the loss rate against OH radicals (LOH), ozone formation potential (OFP), secondary organic aerosol potential (SOAP), and toxicity. Oxygenated VOCs (OVOCs) not only were the most abundant VOCs but also dominated LOH , OFP, and toxicity. Isoprene and anthropogenic VOCs were further identified as precursors of these OVOCs. Aromatics accounted for 5 % of the total VOCs (TVOCs) but contributed 88 % to the SOAP and 10 % to the toxicity. As the primary oxidative intermediates of aromatics were not well characterized by our measurements, the environmental impact of aromatics could be underestimated by our data. Source appointment and ternary analysis of benzene, toluene, and ethylbenzene confirmed the combined contribution of traffic emissions, solvent usage, and biomass burning. This suggests that O 3 precursors are mainly from sources associated with residents' lives, except for solvent usage emissions which contribute to aromatics. Preliminary comparisons between source spectrums of transport sector emissions with positive matrix factorization (PMF)-decomposed ones and our measured ones suggest that vehicle emission patterns of VOCs at high altitude generally follow the ground-level impression. More quantitative data are required to further confirm this point though. Emission reduction strategy analysis for O 3 pollution control highlighted multiple benefits of the simultaneous reduction in NO x originating from diesel vehicle emissions, biomass burning, and background sources (possibly dominated by incense burning). The notable biogenic emission contribution to the OFP was also first confirmed in our study, and this highlights the side effects of the government's pursuit of a greener city. [ABSTRACT FROM AUTHOR]

The disc spring system is applied to the vibration screen, which can effectively reduce the exciting force and improve screening capacity. In this work, the dynamic characteristics and screening performance of the disc spring vibration screen are studied. The modal simulation and experimental results show that the model vibration direction at first natural frequency is consistent with the working direction of the vibration screen. Moreover, the trajectory analysis and discrete element screening simulation prove that the disc spring vibration screen has better screening performance than the coil spring vibration screen. Eventually, by comparing required exciting force under the same amplitude, fatigue life of the spindle bearing, and energy consumption between the coil spring and disc spring vibration screen, it can be found that disc spring vibration screen has better mechanical properties, higher reliability, and lower energy consumption. [ABSTRACT FROM AUTHOR]

Ground surface ozone (O3) is an emerging concern in China due to its complex formation process. In August 2020, field measurements of O3, NOx, and volatile organic compounds (VOCs) were carried out in Hefei's western suburbs. The pollution features of VOCs and O3 formation were thoroughly analyzed. The total VOC concentration was 42.26 ppb, with the dominant contributor being oxygenated VOCs (OVOCs). Seven emission sources were recognized using the positive matrix factorization (PMF) model, including aged air masses, combustion sources, fuel evaporation, industrial emissions, vehicular emission, solvent utilization, and biogenic emission. Ozone generation mainly occurred under an NOx-limited regime based on the zero-dimensional box model analysis. According to the scenario analysis, the 13% cut in O3 might be achieved by the 10% and 30% reduction in NOx and VOCs, respectively. The O3 budget analysis demonstrates its high ozone production rate during the pollution period. The influence of regional transport cannot be ignored for high O3 pollution. This paper provides scientific evidence for O3 production and the strategies of reducing O3 by controlling its precursors. [ABSTRACT FROM AUTHOR]

New particle formation (NPF) is an important source of cloud condensation nuclei (CCN), which affects Earth's radiative balance and global climate. The mechanism and CCN contribution of NPF at the high-altitude mountains, especially in the Tibetan Plateau (TP), was unclear due to lack of measurements. In this study, intensive measurements were conducted at the Nam Co station (4730 m a.s.l.) in the central TP during both the pre-monsoon and summer monsoon seasons. The frequencies of NPF events exhibited evident seasonal differences with 15 % in the pre-monsoon season and 80 % in the monsoon season. The comprehensive analysis of the measured condensation sink (CS), gaseous precursors and meteorological conditions, supplemented by the model simulations of SO 2 and volatile organic compound (VOC), points to the organic involved nucleation as the dominant mechanism. Condensation sink and gaseous sulfuric acid could have no significant effect on the occurrence of NPF events. The frequent NPF events in the summer monsoon season may result from the higher frequency of southerly and southwesterly air masses, which brought the organic precursors to participate in the NPF process. It had increased the aerosol number concentrations and CCN at supersaturation of 1.2 % by more than 2 and 0.6 times compared with those in the pre-monsoon season, respectively. Considering that the smaller particles formed by NPF may further grow and reach CCN size during the following days due to the low-level coagulation sink, the amount of potential CCN in the monsoon season could be much larger than our local measurement results. Our results emphasized the importance of considering the seasonal effect of NPF when simulating the amounts of aerosols and CCN in the high-altitude atmosphere. Long-term investigations with a full set of instrumentation are required for deeper scientific understanding of NPF process and its role in the global budget in the TP. [ABSTRACT FROM AUTHOR]