The modal decomposition study of the non-reactive flow field in a dual-swirl combustor is investigated through the large eddy simulation. The formation mechanism and function of various recirculation ...zones are elaborated by analyzing the time-averaged and instantaneous velocity contours of the center section. The precessing vortex core (PVC) is first visualized by the pressure iso-surface, and the evolution process is presented. Different dimensionality reduction methods are adopted to identify the coherent structures from the flow field. The most energetic spatial structure corresponding to the PVC and its second-order harmonic structure is extracted by the classical proper orthogonal decomposition (POD). The coherent structures with high frequency have relatively low energy content. In addition, a spectral proper orthogonal decomposition (SPOD) method, which can implement spatial-temporal decomposition simultaneously, is introduced to obtain the energy-based spatial structures at all characteristic frequencies. A triple-helix with azimuth wave number m = 3 and a quadruple-helix with azimuth wave number m = 4 are discovered as the third-order and the fourth-order harmonics of single-helix, respectively.
Abstract
Background
Premature ventricular complexes (PVCs) originating in the ventricular outflow tracts are mostly of benign character.
Case Summary
We describe a rare case of pulmonary hypertension ...with severe hypoxaemia and confusion caused by a significant mitral regurgitation (MR) during PVC originating in the left ventricle summit. After successful PVC ablation, all above-mentioned clinical parameters had normalized.
Discussion
Premature ventricular complexes originating in the outflow tracts should be considered as a potential though rare cause of severe MR and pulmonary hypertension.
Near‐infrared (NIR) shielding is essential not only in the building and automobile glass films but also in achieving energy conservation. However, effectively shielding NIR and maintaining high ...transmittance in the visible light region have been great challenges in the past decade. Recently, hexagonal cesium tungsten bronze (CsxWO3) nanoparticles have been widely studied due to the excellent transparency in the visible light region and strong heat‐shielding ability in the NIR region. Herein, a design concept of transparent polyvinyl chloride (PVC)/CsxWO3 composite film, as a heat insulation material for glasses, was proposed. To achieve this purpose, the PVC/CsxWO3 composite film was prepared by incorporating CsxWO3 slurry with better dispersion than traditional CsxWO3 nanoparticles powder into a transparent PVC matrix. By the UV‐Vis‐NIR spectrophotometer characterization, the PVC/CsxWO3 composite film containing 2.1 phr CsxWO3 slurry displays high blocking of NIR (78%) and high transmittance of visible light (76%). In order to further understand the actual heat insulation effect from the PVC/CsxWO3 composite films, the indoor sunlight simulation test and outdoor cooling experiment with solar illumination variations were carried out, which both showed heat insulation that is superior to the antimony tin oxide and indium tin oxide thin films prepared in our previous work. In addition, the mechanical property of PVC/CsxWO3 composite films shows almost no change with the increase of CsxWO3 slurry. The PVC/CsxWO3 composite films simultaneously achieve excellent shielding of NIR and high transmittance of visible light, which makes it an ideal material to alleviate the current building energy consumption issues.
The present study was aimed to investigate the effect of PVC on reproductive competence in adult male Wistar rats. Further, the study also encompasses the protective effect of trans-resveratrol on ...PVC-induced reproductive toxicity in rats. Adult male rats weighing 210–240 g were administered with either PVC at two different doses 100 and 500 mg/kg body weight, orally, daily for 60 days or resveratrol (20 mg/kg body weight/day) through gavage for 60 days on alternate days or both PVC (500 mg/kg body weight) and resveratrol. The results revealed significant reduction in the weights of reproductive organs, epididymal sperm count, viable-, motile-, and HOS-tail coiled sperm and testicular daily sperm production, steroidogenic enzyme activities, serum testosterone levels in PVC treated rats. Conversely the levels of lipid peroxidation increased significantly with a decrease in activity levels of antioxidant enzymes in the testis of PVC exposed rats. Exposure to PVC resulted in reduction in epithelial thickness and seminiferous tubule diameter. No significant changes in the selected reproductive variables were observed in the resveratrol alone treated control rats, whereas, co-administration of resveratrol and PVC resulted in a significant improvement in steroidogenesis and spermatogenesis and mitigated oxidative stress over PVC exposed rats.
•Exposure to PVC reduced reproductive organ weights and spermatogenesis in rats.•Serum testosterone levels decreased significantly in PVC exposed rats.•The testicular oxidative toxicity increased in rats exposed to PVC.•Co-administration of resveratrol ameliorated PVC-induced suppressed reproduction.
Polyvinyl chloride (PVC) is a common thermoplastic polymer with limited optical applications due to its large optical band gap. In this study, organic soluble nitrogen-doped carbon dots (ONCDs) were ...synthesized from 4-aminoantipyrine (4AA) as the precursor through a solvent-free method and employed to reduce the optical band gap of PVC polymer considerably. The formation of ONCDs was investigated through spectroscopic analysis. The synthesized ONCDs were characterized using various techniques, including FTIR, XPS, 13C NMR, 1H NMR, UV–Vis spectroscopy, PL spectroscopy, HR-TEM, and XRD. FTIR and XPS analyses identified the existence of amine, imine, and hydroxy groups on the surface of ONCDs. Furthermore, XPS analysis revealed the presence of carbon, nitrogen, and oxygen via distinguished peaks. 13C NMR and 1H NMR spectra supported the formation of ONCDs. UV–Vis, PLE, and PL spectroscopy techniques provided insights into the light absorption and emission properties of ONCDs. HR-TEM analysis showed uniform ONCDs with a mean particle size of 9 nm. XRD analysis confirmed an amorphous nanostructure of ONCDs with 0.42 nm interlayer spacing. The results illustrate that the absorption of photons by the PVC/ONCDs films covers the entire range of UV to near-infrared. The refractive index was tuned from 1.72 to 2.16 upon adding ONCDs. The increase of the optical dielectric constant (ɛ1) is attributed to the increase in the localized density of states (N/m*). Based on quantum concepts, the optical dielectric loss (ɛ2) was examined to determine the exact value of energy gaps. Taucs model along ɛ2 results was utilized to determine the type of electron transition. The PVC/ONCDs films display a low band gap within the range of 1.52–1.78 eV. These findings demonstrate that the PVC/ONCDs films have improved optical properties and potential for various optoelectronic applications.
Display omitted
•We investigated the formation mechanism of nitrogen-doped carbon dots.•Enhanced optical properties of polyvinyl chloride using nitrogen-doped carbon dots.•Taucs Model and Optical dielectric loss was used to obtain band gap values.•Band gap shrinkage of PVA from 4.76 eV to 1.52 eV were achieved.•Optical dielectric functions used to determine fundamental parameters.
This study provided a geographic and technical matching approach supporting low-carbon style recycling systems, demonstrated using polyvinyl chloride waste (PVCW) generated in 2018 in Mie Prefecture, ...Japan. From a carbon dioxide (CO
) emission basis, mechanical/material recycling (MR) and energy recovery facilities were all allocated full capacity; however, parts of chemical recycling facilities were excluded in the optimal solutions. From the spatial distribution of the allocated result, we confirmed a trend that to achieve the minimum total emissions, the matchings from pretreatment to recycling facilities were done based on a nearby priority rule. From an emission reduction basis, MR accounted for the major proportion of total reductions which was similar to that accessed from an emission basis. Thus, the promotion of MR should be prioritized at the current technical level when optimizing emissions of the whole lifecycle. The number of facilities allocated were substantially reduced; meanwhile, the averaged emission reductions per ton of PVCW disposed were increased from the current level (2.93) to the near-future level (4.99 t-CO
t
). Thus, we concluded that this optimization under a higher technical level was effective to make the current recycling system with more emission reductions (low-carbon environmental effect) and require fewer disposal facilities (cost-saving economic effect). Meanwhile, certain long-distance routes found in solutions implied that technical parameters were more important than geolocation parameters to achieve maximum emission reductions.
•Polyethylene (PE), polyamide nylon (PN6), and polyvinyl chloride (PVC) can efficiently adsorb U(VI)•PN6 has significantly greater affinity for U(VI) compared to PE and PVC.•The formation of ...inner-sphere complexes seems to be the main mechanism between uranyl species and amide moiety of PN6.•Based on Kd, the sorption affinity order was PN6 ≫ PE > PVC in seawater.
The adsorption of radionuclides by microplastics (MPs) has been investigated in de-ionized water and seawater after contamination of the test solutions with ultra-trace levels of U-232. The microplastics used were polyethylene (PE), polyamide naylon (PN6) and polyvinyl chloride (PVC), and the experiments included the effect of pH, contact time and particle size. According to the evaluation of the experimental data obtained (e.g. partition coefficient values, Kd) the sorption efficiency differs significantly from one microplastic to another, the solution pH determines to a large degree the sorption efficiency and the sorption kinetics is basically determined by the radionuclide mass transfer to the surface. In addition, in seawater the adsorption efficiency declines further due to the increased salinity and the presence of competing species. Nevertheless, even under seawater conditions the sorption affinity of the MPs for the radionuclide are significantly higher than those suggested for seawater sediments indicating the cardinal role of microplastics as radionuclide carriers in seawater and other aquatic environments.
This review investigates the latest trends in separation technologies regarding hard-to-recycle thin cables, specifically in the form of end-of-life wire harnesses (WHs). The cables in WHs mainly ...contain copper (Cu) and poly(vinyl chloride) (PVC), which is commonly used to insulate and sheath cables. This review reveals that most separation technologies prioritize the recovery of Cu and overlook that of PVC. The recovery of high-purity PVC is very important because of its incompatibility with other plastics or Cu during recycling treatments. Through this investigation, we confirm that physical treatments, such as stripping and chopping, are insufficient to recover high-purity PVC from thin cables. Instead, a combination of chemical (e.g., swelling of PVC insulation or sheathing of cables under a suitable solvent) and physical (e.g., ball or rod milling and mechanical agitation of swollen cables) treatments can be used to achieve the recovery of high-purity PVC and Cu both for recycling. We believe that recovering metals and plastics from end-of-life cables is vital for sustainable waste management, offering several environmental and economic benefits.
Bionic robot fish, as a kind of underwater robots, has already demonstrated great potential in the ocean. Developing soft actuators for the bionic robot fish has become a key issue. This paper ...proposed a novel robot fishtail consisting of oscillating mechanisms and the stacked soft polyvinyl chloride (PVC) gel actuators. Based on the fish body wave curve used to control the kinematics of fish swimming, a bionic fishtail skeleton with six joints was developed. A stacked PVC gel actuator was fabricated and its mechanical properties and frequency response characteristics were analyzed. On this basis, a fishtail prototype was fabricated, assembled and tested, which showed good agreement with the theoretical prediction. In addition, mechanical properties and frequency response characteristics of the prototype were also studied. The results showed that the swing amplitude of the fishtail could generate a peak value at about 1.5 Hz (2 Hz on land) due to the resonance effect, which was conducive to the swing of the bionic robot fish. And the underwater tests have demonstrated that the fishtail structure can still generate propulsion and move in the water. The conclusion can provide guidance for the design of bionic robot fish in practical application.
Display omitted
●A novel oscillating mechanism based on PVC gel actuators was proposed.●A fishtail based on the oscillating mechanisms using PVC gel actuators was designed and fabricated.●The appearance of the resonant frequency at 1.5 Hz (2 Hz on land) is beneficial to increase the swing amplitude.●The underwater experiments show the fishtail structure can still generate propulsion and move in the water.●This soft robotic system was compared and showed advantages over other robot fishtails.
PDF
