To understand the formation mechanism and evolution process of the perpendicular cavitation vortex (PCV) of an axial flow pump for off-design conditions, turbulent cavitating flows were numerically ...investigated using the rotation curvature-corrected shear stress transport (SST-CC) turbulence model and the Zwart–Gerber–Belamri cavitation model. In this work, the origin and evolution of a PCV were analyzed through a high-speed photography experiment and numerical simulation. The results showed that the PCV came from a secondary tip leakage vortex (S-TLV) and was aggregated by the action of the re-entrant jet, combined with the cavitation bubbles driven by the radial flow to form the cavitation vortex (CV). With the joint action of leakage jet lifting and TLV entrainment, the PCV was reoriented and gradually became perpendicular to the chord direction. Then, the PCV and TLV collided, mixed, and entrained, which formed a strong pressure pulsation. The PCV was gradually divided into upper and lower parts. One part was combined with the residual part of the TLV and flowed to the next blade, and the other part flowed out of the impeller area along the axial direction. At the same time, the generation, evolution, and dissipation of the PCV formed high pulsation amplitudes and frequencies in the middle and rear above the blade suction.
Studies on the tip leakage vortex (TLV) are extensive, while studies on the secondary tip leakage vortex (S-TLV) are rare. To advance the understanding of the formation mechanism of the S-TLV, ...turbulent cavitating flows were numerically investigated using the shear stress transport (SST) turbulence model and the Zwart–Gerber–Belamri cavitation model. The morphology and physical quantity distribution of the S-TLV under two cavitation conditions were compared, and its formation mechanism was analyzed. The results reveal that in the lower cavitation number case, there is a low-velocity zone of circumferential flow near the tip in the back half of the blade. The shear vortices formed by the leakage jet gradually accumulate and concentrate in the low-velocity area, which is one of the main sources of the S-TLV. Meanwhile, the radial jet pushes the vortices on the suction surface to the tip, which mixes with the S-TLV. The flow path formed by the radial jet and the leakage jet is in accordance with the rotation direction of the S-TLV, which promotes the S-TLV’s further development. Under the conditions of a small cavitation number and low flow rate, the circumferential velocity and radial velocity of the fluid near the gap have altered significantly, which is conducive to the formation of the S-TLV.
To understand the effect of cavitation on the tip leakage vortex (TLV), turbulent cavitating flows were numerically investigated using the shear-stress transport (SST) k–ω turbulence model and the ...Zwart–Gerber–Belamri cavitation model. In this work, two computations were performed—one without cavitation and the other with cavitation—by changing the inlet pressure of the pump. The results showed that cavitation had little effect on the pressure difference between the blade surfaces for a certain cavitation number. Instead, it changed the clearance flow and TLV vortex structure. Cavitation caused the TLV core trajectory to be farther from the suction surface and closer to the endwall upstream of the blade. Cavitation also changed the vortex strength distribution, making the vortex more dispersed. The vortex flow velocity and turbulent kinetic energy were lower, and the pressure pulsation was more intense in the cavitating case. The vorticity transport equation was used to further analyze the influence of cavitation on the evolution of vortices. Cavitation could change the vortex stretching term and delay the vortex bending term. In addition, the vortex dilation term was drastically changed at the vapor–liquid interface.
Owing to its discontinuous configuration, segment joint is of particular concern when the shield tunnel lining is exposed to fire. The thermal behavior of such joints when exposed to fire was ...investigated experimentally in full scale. In addition, the effectiveness of using concrete-filled steel tubes (CFSTs) to restore joint strength after a fire was also investigated. Five full-scale reinforced concrete segment joints were fabricated. Four were exposed to the ISO 834 standard fire for 60 or 120 min, with the fifth serving as a control. Two fire-damaged specimens were then strengthened with CFSTs. All five specimens were then loaded to failure at room temperature. It was found that: (1) The effect of the joint gap on the temperature distribution was observed to change markedly during heating; (2) the temperature of the bolt end was much higher than that of the bolt mid-point, insulating the bolt ends is probably called for; (3) the bearing capacity and flexural stiffness of the fire-damaged segment joints can be significantly improved by strengthening with CFSTs.
In order to understand the mechanism of cavity shedding and evolution, turbulent cavitating flows of the twisted hydrofoil were numerically investigated using the k-? turbulence model and the ZGB ...cavitation model. The results of the numerical calculation and the experimental method are basically consistent, which confirms the feasibility of the numerical calculation model. This study has obtained the following conclusions. Firstly, the cavity shedding can be summarized into six stages, and the cavity shape, pressure and velocity field at different stages are displayed, analyzed and compared in detail. Secondly, the shedding of cavity and its evolution are mainly caused by the re-entrant jet and side-entrant jet, in which the former provides the kinetic energy and the latter plays the role of guiding the direction. Thirdly, under the convective shearing action of the re-entrant jet and the main flow, a strong vortex located in the mid-back edge of the hydrofoil is formed, which promotes the transformation of the cavity shape into a U-shaped structure.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Recently, the incidence of melanoma has been on the rise. Patients with distant metastasis share poor prognosis. Increasing studies have been conducted to clarify the molecular mechanisms as well as ...to investigate potential effective therapeutic targets in the development of melanoma. This study focuses on the LncRNA UCA1 and its downstream regulated factors. In our experiments, UCA1 expression was discovered to be upregulated in melanoma tissues and cells, while the depletion of UCA1 led to the inhibition of cell proliferation, invasion and cell cycle arrest. To further our understanding of the mechanisms of UCA1, a system of experiments was built. We found that miR-507 could directly bind to UCA1 at the miRNA recognition site, and that there was a negative correlation between miR-507 and UCA1. Additionally, FOXM1 is a target of miR-507 and can be downregulated by either miR-507 overexpression or UCA1 depletion. Downregulated FOXM1 was analogous to the depletion of UCA1 and the overexpression of miR-507. These results, taken together, provide evidence for a novel UCA1 interaction regulatory network in tumorigenesis of melanoma.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Wheat has a specific preference for NO
3
-
and shows toxicity symptoms under high NH
4
+
concentrations. Increasing the nitrate supply may alleviate ammonium stress. Nevertheless, the mechanisms ...underlying the nitrate regulation of wheat root growth to alleviate ammonium toxicity remain unclear. In this study, we integrated physiological and weighted gene co-expression network analysis (WGCNA) to identify the hub genes involved in nitrate alleviation of ammonium toxicity at the wheat seedling stage. Five NH
4
+
/NO
3
-
ratio treatments, including 100/0 (N
a
), 75/25 (N
r1
), 50/50 (N
r2
), 25/75 (N
r3
), and 0/100 (N
n
) were tested in this study. The results showed that sole ammonium treatment (N
a
) increased the lateral root number but reduced root biomass. Increasing the nitrate supply significantly increased the root biomass. Increasing nitrate levels decreased abscisic acid (ABA) content and increased auxin (IAA) content. Furthermore, we identified two modules (blue and turquoise) using transcriptome data that were significantly related to root physiological growth indicators.
TraesCS6A02G178000
and
TraesCS2B02G056300
were identified as hub genes in the two modules which coded for plastidic ATP/ADP-transporter and
WRKY62
transcription factors, respectively. Additionally, network analysis showed that in the blue module,
TraesCS6A02G178000
interacts with downregulated genes that coded for indolin-2-one monooxygenase, SRG1, DETOXIFICATION, and wall-associated receptor kinase. In the turquoise module,
TraesCS2B02G056300
was highly related to the genes that encoded
ERD4
,
ERF109
,
CIGR2
, and WD40 proteins, and transcription factors including
WRKY24
,
WRKY22
,
MYB30
, and
JAMYB
, which were all upregulated by increasing nitrate supply. These studies suggest that increasing the nitrate supply could improve root growth and alleviate ammonium toxicity through physiological and molecular regulation networks, including ROS, hormonal crosstalk, and transcription factors.
Waste printed circuit boards (WPCBs) are resource-rich but hazardous, demanding innovative strategies for post-consumer collection, recycling, and mining for economically precious constituents. A ...novel technology for disassembling electronic components from WPCBs is proposed, using hot air to melt solders and to separate the components and base boards. An automatic heated-air disassembling equipment was designed to operate at a heating source temperature at a maximum of 260 °C and an inlet pressure of 0.5 MPa. A total of 13 individual WPCBs were subjected to disassembling tests at different preheat temperatures in increments of 20 °C between 80 and 160 °C, heating source temperatures ranging from 220 to 300 °C in increments of 20 °C, and incubation periods of 1, 2, 4, 6, or 8 min. For each experimental treatment, the disassembly efficiency was calculated as the ratio of electronic components released from the board to the total number of its original components. The optimal preheat temperature, heating source temperature, and incubation period to disassemble intact components were 120 °C, 260 °C, and 2 min, respectively. The disassembly rate of small surface mount components (side length ≤ 3 mm) was 40–50% lower than that of other surface mount components and pin through hole components. On the basis of these results, a reproducible and sustainable industrial ecological protocol using steam produced by industrial exhaust heat coupled to electronic-waste recycling is proposed, providing an efficient, promising, and green method for both electronic component recovery and industrial exhaust heat reutilization.
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IJS, KILJ, NUK, PNG, UL, UM
e16128
Background: The combination of systemic therapies and hepatic arterial infusion chemotherapy (HAIC) showed promising outcomes for advanced hepatocellular carcinoma (HCC). Raltitrexed, an ...antimetabolic drug with long plasma concentrations half-life, could be used in short infusions. HAIC with raltitrexed plus oxaliplatin (RALOX) was reported to be effective and safe in HCC. This study aimed to investigate the efficacy and safety of combined camrelizumab and lenvatinib plus RALOX-HAIC as a first-line treatment in advanced HCC patients. Methods: This single-arm, phase II study included treatment-naive adult (≥18 years) patients with HCC in BCLC stage B and C and Child-Pugh score small or equal to 7 points (NCT05003700). Patients were administrated with RALOX-HAIC (oxaliplatin 100mg/m
2
, raltitrexed 3 mg/m
2
, every 3 weeks), combined with camrelizumab (200mg by IV infusion, every 3 weeks) and lenvatinib (8mg orally once daily) for 6 cycles, followed by maintenance therapy with camrelizumab and lenvatinib until disease progression or unacceptable toxicity. The primary endpoint was objective response rate (ORR). Results: Between March 2021 and October 2022, 36 patients (33 men and 3 women; median age, 54.5 years) were enrolled. The median tumor size was 11.4 cm, 86.1% of patients had portal vein invasion, and 38.9% had extrahepatic metastasis. As of February 1, 2023, the median follow-up was 14.2 months, and all patients had at least one post-baseline tumor assessment. The confirmed ORR per RECIST v1.1 and per mRECIST was respectively 61.1% (95% CI, 44.4−77.8), and 83.3% (95% CI, 70.5−96.1) including 4(11.1%) patients who achieved a complete radiological response. The median progression-free survival (PFS) time was 13.8 months (95%CI, 8.8-20.5) per RECIST v1.1. The 6-month and 12-month overall survival rate were 94.3% and 64.9%, respectively. Grade 3-4 treatment-related adverse events (AEs) occurred in 75% of patients, and the most common were neutropenia (44.4%) thrombocytopenia (36.1%), elevated aspartate aminotransferase (25.0%), and leucopenia (19.4%). All AEs were expected and manageable, and no treatment-related deaths were reported. Conclusions: Combination treatment with camrelizumab and lenvatinib plus RALOX-HAIC showed promising antitumor activity and acceptable toxicity in patients with advanced HCC. Clinical trial information: NCT05003700 .
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