Improved Particle Swarm Optimization for Selection of Shield Tunneling Parameter Values

This article proposes an exponential adjustment inertia weight immune particle swarm optimization (EAIW-IPSO) to enhance the accuracy and reliability regarding the selection of shield tunneling parameter values. According to the iteration changes and the range of inertia weight in particle swarm optimization algorithm (PSO), the inertia weight is adjusted by the form of exponential function. Meanwhile, the self-regulation mechanism of the immune system is combined with the PSO. 12 benchmark functions and the realistic cases of shield tunneling parameter value selection are utilized to demonstrate the feasibility and accuracy of the proposed EAIW-IPSO algorithm. Comparison with other improved PSO indicates that EAIW-IPSO has better performance to solve unimodal and multimodal optimization problems. When solving the selection of shield tunneling parameter values, EAIW-IPSO can provide more accurate and reliable references for the realistic engineering

Study on the breakdown characteristics of multiple-reignition secondary arcs on EHV/UHV transmission lines

A long-gap AC arc with a length of more than ten meters (secondary arc) are normally generated at the short-circuit arc channel after a single-phase-to-ground fault. In previous studies, arc breakdowns of secondary arcs have mainly been considered as electrical breakdowns, ignoring the role of heat in the arc channel. Besides, the extinction-reignition theory of secondary arc, i.e., dielectric strength recovery theory, still lack the support of experimental data. In this study, based on the equivalent experiments performed in the laboratory, the influences of compensation degree of transmission lines, initial recovery voltage gradient of air gap, test current, wind speed, and wind direction on the breakdown characteristics of secondary arcs are studied and statistically analyzed. The laws of the transient recovery voltage (TRV) and of the rate of rise of recovery voltage (RRRV) also studied by considering the influencing factors mentioned above. The results of this study will provide a more complete experimental basis for the theory of extinction–reignition of secondary arcs and a deeper understanding of the transient characteristics of arc breakdow

Research on the Mechanism of REITs on China's Infrastructure Construction Under the Background of High-Quality Development

The long-term and high-speed investment in infrastructure construction in China has brought some adverse effects, which are mainly reflected in the low input-output ratio efficiency, prominent financing channel problems and higher debt leverage ratio. It is obviously inconsistent with the high quality economic development proposed by Our country. This paper briefly introduces the basic concepts and characteristics of REITs, lists some traditional financing methods and their disadvantages in the field of infrastructure, and highlights the advantages of infrastructure REITs. In the empirical part, based on the case of Soochow Suzhou Industrial Park, the benefits of REITs are quantitatively analyzed to explore the role that REITs can play in the development of infrastructure construction industry under the background of high-quality development.</jats:p

Effect of Subcritical Fluid Extraction on the High Quality of Headspace Oil from Jasminum sambac (L.) Aiton

Abstract Subcritical fluid extraction (SFE), as a novel method, was applied to investigate the yield, quality, and sensory evaluation of headspace oil from Jasminum sambac (L.) Aiton in comparison with petroleum ether extraction (PEE). The results indicated that the yield of the headspace oil using SFE was significantly higher (P &amp;lt; 0.05) than when using PEE. SFE contributed to obtaining alcohols and ethers, prevented the thermal reaction of terpenes, and reduced α-caryophyllene and β-caryophyllene in the headspace oil. The contents of linalool (21.90%) and benzyl acetate (16.31%) were higher via SFE than PEE. In addition, the sensory evaluation of SFE was superior to PEE, indicating a fresh, jasmine-like odor and green-yellow color. Thus, SFE is an improved method for obtaining natural headspace oil from jasmine flowers.</jats:p

Effect of Nozzle Structure on Energy Separation Performance in Vortex Tubes

Vortex tubes are used in specialized scenarios where conventional refrigeration systems are impractical, such as tool cooling in CNC machines. The internal flow within a vortex tube is highly complex, with numerous factors influencing its energy separation process, and the coefficient of performance for refrigeration is relatively low. To investigate the impact of nozzle type on energy separation performance, vortex tubes with straight-type, converging-type, and converging&ndash;diverging-type nozzles were designed. Numerical simulation was conducted to explore their velocity, pressure, and temperature distribution at an inlet pressure of 0.7 MPa and a cold mass fraction of 0.1~0.9. The cooling effect, temperature separation effect, cold outlet mass flow rate, and refrigeration capacity of vortex tubes were assessed. The converging&ndash;diverging nozzle increases the gas velocity at the nozzle outlet while it does not significantly enlarge the airflow velocity in the vortex chamber. As the cold mass fraction rises, the cooling performance and cooling capacity of three vortex tubes first increase and then decrease. The maximum cooling effect and cooling capacity of vortex tubes are achieved at cold mass fractions of 0.3 and 0.7, respectively. Under identical conditions, the vortex tube with a converging nozzle achieves the highest cooling effect with a temperature drop of 36.6 K, whereas the vortex tube with converging&ndash;diverging nozzles possesses the largest gas flow rate, and the cooling capacity reaches 542.4 W. The vortex tube with straight nozzles exhibits the worst refrigeration performance with a cooling effect of 33.6 K and a cooling capacity of 465.9 W. It is indicated that optimizing the nozzle structure of the vortex tube to reduce flow resistance contributes to enhancing both the gas velocity entering the swirl chamber and the resultant refrigeration performance

3D printed zirconia ceramic tool for bone repair with multifunction of drug release, drilling and implantation

Ceramics is a promising material that has been widely used as artificial bones. However, most available investigations were devoted to new material development and implant structure design, while few of studies focused on innovative hybrid implants that can act not only as implants but also as surgery tools for solving specific health issues. This paper innovatively designed and additively-manufactured a zirconia ceramic surgery tool, which can not only act as a drilling tool, but also retain itself in the drilled hole after the surgery as bone scaffold, at the meantime delivery active ingredient (Vitamin C) for fast recovery. To achieve early intervention, the proposed zirconia ceramic tool was additively manufactured with inter-connected pore structures that can benefit the recovery. The zirconia ceramic surgery tools (with 50 %, 70 % and 80 % porosity) showed the required mechanical properties to act as a drilling tool. The tool also showed drug releasing function with the different diffusion rates based on drug diffusion experiments. The zirconia ceramic tool with Vitamin C coating also showed enhanced cell adhesion and accelerated cell growth based on the osteoblast induction assessment. Based on above, the proposed zirconia ceramic tool is expected to bring new possibilities for wide applications of ceramic tools in surgeries

Myopic choroidal neovascularization with neovascular signal around perforating scleral vessel prone to recur after anti-VEGF therapy

Abstract Background To compare the recurrence of myopic choroidal neovascularization (mCNV) based on the neovascular signal of mCNV around the perforating scleral vessel (PSV). Methods A consecutive series of naïve patients with mCNV accepted anti-VEGF therapy with a minimum 12-month follow-up period. The neovascular signal relationship between PSV and mCNV were classified into the presence of neovascular signal of CNV around PSV or not. The recurrence of mCNV, best-corrected visual acuity (BCVA), hyperreflective foci height, CNV area and CNV flow area were analyzed between two groups. Results Neovascular signal of CNV around PSV was detected in 20 eyes (39.2%). The one-year recurrence rate in the group with neovascular signal of CNV around PSV was significantly higher than that in the group without neovascular signal of CNV around PSV (P = 0.045). The recurrence time in the group with neovascular signal around PSV was shorter than that in the group without neovascular signal around PSV (P = 0.030). Cox proportional hazard model showed that the presence of neovascular signal of CNV around PSV [hazard ratio (HR): 2.904] and subfoveal choroidal thickness ≤ 50 μm (HR: 0.368) were risk factors for recurrence of mCNV. In the group with neovascular signal around PSV, the BCVA was worse (P = 0.024) and the CNV flow area was more unstable (P = 0.027) after therapy. Conclusions PSV was commonly detected in patients with mCNV. The presence of neovascular signal of CNV around PSV was prone to recur with a shorter time in mCNV patients