Cavity Size Research Articles

The impact of ventricular remodeling on quality-of-life outcomes after Transcatheter aortic valve replacement

BackgroundAmong patients with aortic stenosis, ventricular remodeling by hypertrophy can limit the augmentation of flow with exertion, even after valve intervention. However, the effect of hypertrophy on quality of life (QoL) improvement has not been studied. We aimed to determine the effect of ventricular hypertrophy on QoL outcomes after transcatheter aortic valve replacement (TAVR). MethodsAll patients undergoing TAVR from 2011 to 2021 at our institution were included. Groups were divided into none/mild ventricular hypertrophy (non-remodeled, NR) and moderate/severe left ventricular hypertrophy (VH) according to guideline-recommended cut-offs for left ventricular (LV) wall thickness. The Kansas City Cardiomyopathy Questionnaire (KCCQ) was utilized to assess QoL; primary outcome was KCCQ change <5 from baseline to 30 days and 1 year. ResultsWe analyzed 679 patients (NR: N = 389, VH: N = 290). Groups differed by septal thickness (1.12 cm vs. 1.44 cm, p < 0.001), posterior wall thickness (1.08 cm vs. 1.33 cm, p < 0.001), and LV internal diastolic diameter (4.34 cm vs. 4.19 cm, p = 0.006). The primary outcome was similar between NR and VH at 30 days (31.6 % vs. 28.6 %, p = 0.449) and 1 year (27.7 % vs. 21.5 %, p = 0.217). NR and VH experienced similar proportions of worsening, no change, or small, moderate, and large improvements in KCCQ score. Both groups experienced similar domain score changes and New York Heart Association class improvement. A subgroup analysis of VH patients did not reveal interaction with cavity size or stroke volume. ConclusionPatients with significant ventricular remodeling by hypertrophy and aortic stenosis have similar QoL changes after intervention compared to patients without significant remodeling.

Defect-controlled confined growth of nano-MOFs to prepare materials with hierarchical micro/mesoporous structures for efficient CO2 capture

In recent years, nanoporous materials with special structure have been widely used in various fields. In view of the poor stability of MOFs materials and the poor mass transfer ability, in this study, we developed a simple method to restrict the growth of UiO-66-NH2 crystals in hollow silica by “vacuum evaporation” strategy, different kinds of acid regulators were introduced, to obtain a composite material with hierarchical pore structure. By characterizing the physical chemistry and microstructure of the composite adsorbent, and calculating the structural defects under different acid regulation, the adsorption and desorption performance and stability of the adsorbent for CO2 were comprehensively investigated. The mechanism of action on CO2 was further analyzed by in-situ infrared and other techniques. The results show that the change of coordination environment and coordination rate caused by the competition of organic acids, which increases the defects and reduces the nucleation and aggregation effect of UiO-66-NH2, promotes the formation of hierarchical pore structure of the composites. Among them, benzoic acid is the best regulating monocarboxylic acid, which makes UiO-66-NH2 have good dispersion in the cavity and suitable crystal size. The specific surface area of the composite material is 717.96 m2·g-1. At the same time, due to its excellent CO2 adsorption capacity (3.35mmol·g-1) at 298K and 1.06bar, it is 48.07% higher than the original UiO-66-NH2. In order to accomplish the goal of effective CO2 adsorption performance of composites, this study offers a novel approach for the synthesis and modification of MOFs-based composites.

To investigate the impact of revised diagnostic algorithm on presentation of multidrug-resistant tuberculosis cases at a referral centre in India

ABSTRACT Introduction: A shift in policy has occurred with the introduction of molecular diagnostic tools for the upfront diagnosis of all cases of tuberculosis, including drug-resistant tuberculosis. The impact of this shift in policy on severity of disease was studied, and comparisons were drawn between the year 2015 and 2020. Study Type and Design: This was an observational study conducted between 2020 and 2021. Seventy patients of MDR-TB with or without additional drug resistance, hospitalized in the year 2015 and 2020, were studied. Results: The study reveals a substantial reduction in the median time from the onset of symptoms to diagnosis between 2015 and 2020. Specifically, the median duration decreased from 12 weeks in 2015 to 8 weeks in 2020. Moreover, we found that in 2015, all cases under study had a history of tuberculosis in comparison to 2020. Additionally, there was a higher incidence of anemia in 2015 compared to 2020. In the radiological examination, it was observed that in 2015, a higher frequency of cases exhibited cavitations, bronchiectasis, and fibrosis on chest X-rays compared to the findings in 2020. The mean cavity size in 2015 measured 6.73 cm, while in 2020, it averaged 4.06 cm. Additionally, we noticed a higher occurrence of significantly advanced cases in 2015 in contrast to 2020. Conclusion: The implementation of the new policy of upfront DST was noted to decrease the time required for diagnosis and bacterial load as ascertained from degree of sputum smear positivity, radiological lesions, and severity of anemia.

Gate tunable edge magnetoplasmon resonators

AbstractQuantum Hall systems are platforms of choice to study topological properties of condensed matter systems and anyonic exchange statistics. In this work we have developed a tunable radiofrequency edge magnetoplasmonic resonator controlled by both the magnetic field and a set of electrostatic gates, meant to serve as a versatile platform for future interferometric devices designed to evidence non-abelian anyons. In our device, gates allow us to change both the size of the resonant cavity and the electronic density of the two-dimensional electron gas. We show that we can continuously control the frequency response of our resonator, making it possible to develop an edge magnetoplasmon interferometer. As we reach smaller sizes of our resonator, finite size effects caused by the measurement probes manifest. In the future, such device will be a valuable tool to investigate the properties of non-abelian anyons in the fractional quantum Hall regime.

Intestinal-Targeted Digestion of Heme Chloride by Forming Inclusion Complexes In Vitro.

Hemin, a heme-like compound with significant biological activity, shows promise as an iron supplement for humans. Nonetheless, its poor solubility in water greatly impedes its absorption and utilization. To surmount this obstacle, researchers have chosen various cyclodextrins with distinct cavity sizes and derivative groups to act as hosts, forming inclusion complexes with hemin chloride. Among these, γ-cyclodextrin has been identified as the optimal carrier, based on a thorough evaluation of its encapsulation efficiency, solubility, and molecular docking. Multiple characterization techniques further confirmed the formation of these inclusion complexes. Results from IEC-6 cell experiments indicated that the cytotoxicity of the inclusion complexes was lower than that of FeSO4. Static and dynamic gastrointestinal simulation digestion systems were established, and the results showed that the bioavailability of the inclusion complex was significantly higher than that of raw hemin. Additionally, only about 0.29% of hemin chloride is digested by gastric enzymes, whereas 9.52% is digested by pancreatic enzymes in the static gastrointestinal simulation digestion system, with similar outcomes observed in the dynamic system. These findings suggest that targeted digestion in the intestine significantly enhances the bioavailability of hemin chloride by forming inclusion complexes in vitro.

RV Measurements of Directly Imaged Brown Dwarf GQ Lup B to Search for Exosatellites

GQ Lup B is one of the few substellar companions with a detected cicumplanetary disk (CPD). Observations of the CPD suggest the presence of a cavity, possibly formed by an exosatellite. Using the Keck Planet Imager and Characterizer (KPIC), a high-contrast imaging suite that feeds a high-resolution spectrograph (1.9–2.5 µm, R∼35,000), we present the first dedicated radial velocity (RV) observations around a high-contrast, directly imaged substellar companion, GQ Lup B, to search for exosatellites. Over 11 epochs, we find a best and median RV error of 400–1000 m s−1, most likely limited by systematic fringing in the spectra due to transmissive optics within KPIC. With this RV precision, KPIC is sensitive to exomoons 0.6%–2.8% the mass of GQ Lup B (∼30 M Jup) at separations between the Roche limit and 65 R Jup, or the extent of the cavity inferred within the CPD detected around GQ Lup B. Using simulations of HISPEC, a high resolution infrared spectrograph planned to debut at W.M. Keck Observatory in 2026, we estimate future exomoon sensitivity to increase by over an order of magnitude, providing sensitivity to less massive satellites potentially formed within the CPD itself. Additionally, we run simulations to estimate the amount of material that different masses of satellites could clear in a CPD to create the observed cavity. We find satellite-to-planet mass ratios of q > 2 × 10−4 can create observable cavities and report a maximum cavity size of ∼51 R Jup carved from a satellite.

Development and evaluation of a buoyancy-driven airflow window with multioperation modes

This study introduces a novel, cost-effective window-integrated passive system (WIPS) that enhances indoor air quality and maintains comfortable temperatures throughout both summer and winter. The WIPS utilizes buoyancy-driven air flow through dual air cavities that alternately preheat or cool the incoming air depending on the season. The system’s design was optimized for Seoul, Korea, through computational fluid dynamics (CFD) simulations using Fluent 2021 R2 software, which employed a Reynolds-Averaged Navier-Stokes (RANS) model with RNG κ-ε turbulence modeling. Key design adjustments included the use of glass and unplasticized polyvinyl chloride (UPVC) to minimize unintended airflow, as well as modifications to the geometry and size of the air cavities to maximize efficient air flow and thermal effectiveness. The optimized design demonstrated significant improvements in thermal performance, achieving a preheating effect up to 35 °C in winter and reducing indoor temperatures by 10 °C in summer. These results underline the potential of WIPS to provide a sustainable solution for building ventilation and climate control.

Ligand-Controlled Regiodivergent Ring Expansion of Benzosilacyclobutenes with Alkynes en Route to Axially Chiral Silacyclohexenyl Arenes.

A ligand-controlled regiodivergent and enantioselective ring expansion of benzosilacyclobutenes with internal naphthyl alkynes has been achieved by adjusting the ligand cavity size. The ligand (S)-8H-binaphthyl phosphoramidite, featuring small methyl groups on its arms, provides a spacious cavity that favors sterically demanding Si-Csp3 ring expansion, predominantly yielding axially chiral (S)-1-silacyclohexenyl arenes. In contrast, the ligand (R)-spiro phosphoramidite, with bulky t-Bu groups on its arms, offers a compact cavity that facilitates less sterically demanding Si-Csp2 ring expansion, leading primarily to axially chiral (S)-2-silacyclohexenyl arenes. Density functional theory calculations delineate distinct mechanistic pathways for each ring expansion route and elucidate their regio- and enantioselectivity.

Impacts of impeller blade number on centrifugal pump performance under critical cavitation conditions

The number of impeller blades is a significant geometric parameter that considerably impacts centrifugal pump performance. A transient numerical analysis of a centrifugal pump is conducted to examine the influence of the variable impeller blade number on pump performance under critical cavitation conditions. Six different impellers with 3, 5, 7, 8, 9, and 11 blades are examined numerically at a rotational speed of 2900 r/min when other impeller parameters remain unchanged. Fields of interior flow and properties of centrifugal pumps are studied concerning static pressure, velocity magnitude, and vapor volume fraction using ANSYS Fluent to perform the numerical simulation. The results show that numerical analysis can accurately predict centrifugal pump internal flow. The current results match experimental and numerical data for the NPSH, with a 4.65% discrepancy. Blade numbers affect the flow field and pressure amplitude, especially at the outlet region. As blade numbers increase, pressure increases, and the impeller with 11-blade has the maximum pressure amplitude. The impeller with a seven-blade achieved its highest efficiency level, exhibiting a 0.48% improvement under non-cavitation conditions and a 1.4% improvement under critical cavitation conditions compared to the original model. Furthermore, the cavity size on an individual blade of a model with three-blade is more extensive compared to other models. In addition, the impeller with a nine-blade exhibits the lowest value of the vapor volume percentage. This research analyses the influence of different blade numbers on the performance of centrifugal pumps while operating under critical cavitation conditions. It aims to provide novel insights into the flow characteristics associated with such circumstances.

Significance of changes in cavity after treatment in Mycobacterium avium complex pulmonary disease

Cavities are characteristic radiological features related to increased mycobacterial burden and poor prognosis in Mycobacterium avium complex pulmonary disease (MAC-PD). However, cavity changes following treatment and their clinical implications remain unknown. We aimed to elucidate whether cavity obliteration or reduction in cavity size or wall thickness correlates with microbiological cure. In total, 136 adult patients with cavitary MAC-PD treated for ≥ 6 months between January 1st, 2009, and December 31st, 2021, in a tertiary referral centre in South Korea were enrolled. The cavity with the largest diameter at treatment initiation was tracked for size and thickness changes. Following median treatment of 20.0 months, 74 (54.4%) patients achieved microbiological cure. Cavity obliteration, achieved in 58 (42.6%) patients at treatment completion, was independently associated with microbiological cure. In patients with persistent cavities, size reduction of ≥ 10% was significantly associated with microbiological cure, whereas thickness reduction was not. Five-year mortality rates in patients with cavity obliteration, persistent but reduced cavity, and persistent cavity without shrinkage were 95.6%, 72.1%, and 65.3%, respectively (P < 0.001). In conclusion, cavity obliteration or shrinkage at treatment completion is associated with microbiological cure and reduced mortality in MAC-PD, suggesting that cavity changes could serve as a proxy indicator for treatment response.

Modeling Electronic Devices with a Casimir Cavity

The Casimir effect has been exploited in various MEMS (micro-electro-mechanical system) devices, especially to make sensitive force sensors and accelerometers. It has also been used to provide forces for a variety of purposes, for example, for the assembly of considerably small parts. Repulsive forces and torques have been produced using various configurations of media and materials. Just a few electronic devices have been explored that utilize the electrical properties of the Casimir effect. Recently, experimental results were presented that described the operation of an electronic device that employed a Casimir cavity attached to a standard MIM (metal–insulator–metal) structure. The DC (direct current) conductance of the novel MIM device was enhanced by the attached cavity and found to be directly proportional to the capacitance of the attached cavity. The phenomenological model proposed assumed that the cavity reduced the vacuum fluctuations, which resulted in a reduced injection of carriers. The analysis presented here indicates that the optical cavity actually enhances vacuum fluctuations, which would predict a current in the opposite direction from that observed. Further, the vacuum fluctuations near the electrode are shown to be approximately independent of the size of the optical cavity, in disagreement with the experimental data which show a dependence on the size. Thus, the proposed mechanism of operation does not appear correct. A more detailed theoretical analysis of these devices is needed, in particular, one that uses real material parameters and computes the vacuum fluctuations for the entire device. Such an analysis would reveal how these devices operate and might suggest design principles for a new genre of electronic devices that make use of vacuum fluctuations.

Association of polymorphism of the glutathione-s-transferase M1 gene and tumor necrosis factor alpha with the formation and size of decay cavities in patients with pulmonary tuberculosis

The aim. To study the association of polymorphic variants of the GSTM1 (E/D) and TNF-s (308G&gt;A (rs1800629) genes with the formation of decay cavity sizes in patients with pulmonary tuberculosis.Material and methods. The study group is represented by 335 patients suffering from pulmonary tuberculosis (212 people were diagnosed with pulmonary tuberculosis for the first time; 123 people with chronic pulmonary tuberculosis) aged 18 to 65 years; receiving an intensive phase of chemotherapy. To conduct molecular genetic studies; 335 people had whole blood taken from a vein into a test tube with EDTA. Genomic DNA was isolated using Arrow Blood DNA 500 reagent kits from whole blood (at the NorDiag Arrow station). After; the polymerase chain reaction was staged in real time using sets of reagents for genotyping SNPs: GSTM1 (E/D) and TNF-s (–308G&gt;A (rs1800629).Results and discussion. In patients with pulmonary tuberculosis; the genotype DD of the gene GSTM1 (E/D) and the genotype GG of the gene TNF-s –308G&gt;A (rs1800629) is most often associated with the formation of the size of decay cavities.Conclusion. It is advisable to introduce genotyping of the GSTM1 and TNF-s genes into the practice of a phthisiologist in order to predict the probability of the formation of the size of decay cavities in patients with pulmonary tuberculosis.

Submucosal cystic adenomyosis: a report of five cases and review of the literature

AimTo investigate the clinical characteristics, diagnosis, and clinical treatment of submucosal cystic adenomyosis.MethodsThe clinical data of five cases of patients with submucosal cystic adenomyosis in our hospital from January 2020 to June 2023 were retrospectively analyzed.ResultsThe average age of the patients was 37.8 ± 4.5 years old, three of them experienced prolonged menstruation and heavy menstrual bleeding. All patients had a history of abnormal uterine bleeding and mild to moderate dysmenorrhea, with a VAS score of 2.8 ± 1.6. The average Carbohydrate antigen 125 (CA125) value was 29.9 ± 23.6U/ml. Two out of the five patients (40%) had CA125 values above the upper limit of normal. The nodules had a diameter of 3.2 ± 1.3 cm and a cavity size of 1.3 ± 0.7 cm. Color ultrasound revealed hypo or iso or anechoic echoic cysts, and blood flow signals were detected. The magnetic resonance imaging (MRI) findings varied among each patient. All the patients underwent hysteroscopy and resection of uterine cavity-occupying lesions, and no recurrence was observed.ConclusionsThe clinical features of submucosal cystic adenomyosis include abnormal uterine bleeding and menstrual changes, and the degree of dysmenorrhea is generally not severe. The diagnostic utility of CA125 in submucosal cystic adenomyosis may be limited. The three-dimensional ultrasound and MRI are valuable preoperative examination methods currently. Hysteroscopy can not only diagnose submucosal cystic adenomyosis, but also treat it, and preserve the fertility function of the patient.

Nonlinear dynamics of a bubble cluster in liquid cavity wrapped by elastic medium

Abstract According to the modified nucleation theory, gas nuclei can generate and grow into cavitation bubbles when’s the liquid pressure exceeds a threshold in a cavity. Based on the modified nucleation theory, the growth process of the gas nuclei in a liquid cavity can be simplified to two “events”, and the full confinement effects of the surrounding elastic medium of the cavity was considered by including the bulk modulus in the equation of state. The dynamical equations were derived to model the nonlinear oscillation of the multi-bubble system in the cavity. The effects of acoustic parameters, the initial radius and the total number of bubbles on bubble dynamics were investigated numerically. It is found that bubble behaviors are sensitive to the acoustic field. In the low frequency region (f &lt;1MHz), bubble oscillation exhibits a modulated waveform, and fundamental, subharmonic and harmonic modes can be found in the acoustic response curve. The oscillations of confined bubbles diminish with increasing frequency. In the high frequency region (f &gt;1MHz), the confinement state affects the acoustic response of the gas nuclei, and the growth rate differ by a factor of 5 difference in the presence of shelled or unbounded elastic confinement of the cavity. Therefore, the suppression or enhancement of cavitation growth and collapse in confined cavity can be modulated by a variety of factors, such as the total number of nuclei, cavity size, acoustic frequency and amplitude, negative pressure, and elastic medium, which have a synergistic influence on the confined cavitation process.

Modeling and scaling of cavitation compliance in Venturi

Understanding cavitation compliance in Venturi is important for research on system oscillations in fluid machinery, which describes the responsiveness of the cavity size to alternating inflow parameters. To consider both Venturi geometries and inflow conditions in evaluating the cavitation compliance, the cavitation region is modeled as a large vapor bubble, based on the experimental characteristics of the attached cavity characterizing the cavity size. Steady-state numerical solutions of cavity sizes show the influencing trends by geometrical and inflow parameters consistent with experiments. According to the analytical solution approximating the numerical solution, effective cavitation number σe and effective length ratio L̃* are defined to unify these influencing parameters. Based on the causes of cavitation pressure drops at the throat indicated by σe, cavitation compliance can be categorized into two regimes. Regime I features a smaller σe, and the dynamic pressure dominates in the pressure drops, theoretically resulting in L̃*∝σe−9. Regime II features a larger σe, and the bend-flow inertia and dynamic pressure are comparable, resulting in L̃*∝σe−2 in contrast. The power-law predictions of cavitation compliance are validated by experiments and literature.

Novel mixed matrix membranes containing calixarene for enhanced CO2/N2 separation

Calixarene possessing advantages of small intrinsic cavity size, small particle dimension, and facile dispersion or dissolution in common solvents, is promising filler candidates in mixed matrix membranes (MMMs) for gas separation. Herein, the supramolecular C-propylpyrogallol[4]arene (PgC3) was successfully synthesized via a phenolic resin condensation reaction. It was then incorporated into a polyether-polyamide block copolymer (Pebax-1657) to prepare mixed matrix membranes (MMMs) with varying PgC3 loadings for CO2/N2 separation. The formation of hydrogen bonds between PgC3 and Pebax facilitated the uniform dispersion of PgC3 within the polymer matrix, enhancing interfacial compatibility. The incorporation of PgC3 significantly enhanced the CO2/N2 selectivity of the Pebax while preserving its permeability. The 1 wt% PgC3/Pebax MMMs performs the best CO2/N2 selectivity of 58.6, substantially higher than that of pristine Pebax membrane (32.4). This improvement can be attributed to the strong affinity between the abundant –OH groups in PgC3 and CO2 molecules. Moreover, the PgC3/Pebax MMMs exhibited exceptional stability under operating pressures of up to 5 bar, maintaining its performance consistently throughout a demanding100-hour test. The good separation performance together with the excellent stability enables PgC3 a promising filler in MMMs for CO2/N2 or other gas separations.

Binary-Cooperative Ultrathin Porous Membrane for Gas Separation.

The construction of ultrathin porous membranes with stable structures is critical for achieving efficient gas separation. Inspired by the binary-cooperative structural features of bones and teeth-composed of rigid hydroxyapatite and flexible collagen, which confer excellent mechanical strength-a binary-cooperative porous membrane constructed with gel-state zeolitic imidazolate frameworks (g-ZIFs), synthesized using a metal-gel-induced strategy, is proposed. The enlarged cavity size and flexible frameworks of the g-ZIF nanoparticles significantly improve gas adsorption and diffusion, respectively. After thermal treatment, the coordination structures forming rigid segments in the g-ZIF membranes appear at the stacked g-ZIF boundaries, exhibiting a higher Young's modulus than the g-ZIF nanoparticles, denoted as the flexible segments. The g-ZIF membranes demonstrate excellent tensile and compression resistances, attributed to the effective translation of binary-cooperative effects of rigidity and flexibility into the membranes. The resulting dual-aperture structure, composed of g-ZIF nanoparticles surrounded by nanoscale apertures at the boundaries, yields a membrane with a stable CO2 permeance of 4834 GPU and CO2/CH4 selectivity of 90 within 3.0MPa.

449. CAN LARGE ANASTOMOTIC LEAKAGE AFTER ESOPHAGEAL SURGERY BE TREATED BY ENDOLUMINAL VACUUM-ASSISTED CLOSURE (EVAC THERAPY)?: A CASE REPORT

Abstract Background Anastomotic leakage after esophageal surgery is a deadly complication which approach is still under debate. The high morbimortality of the surgical approach has led to debate whether there are any alternative treatments. The appropriate strategy is based on many factors that include patient’s general conditions, size of anastomotic leakage and diagnosis delay. EVAC (Endoscopic vacuum assisted wound closure) is an emerging technique to treat these patients that can be placed either into the cavity or in the lumen under endoscopic guidance. It is then connected to a negative continuous pressure of 75-125mmhg and then reviewed after 3-4 days. Methods A 62-year-old man with esophageal squamous cell carcinoma underwent neoadjuvant chemoradiotherapy, followed by a minimally invasive Mckeown esophagectomy. On the fourth postoperative day, inflammatory indexes increased, and a CT scan showed an anastomotic leakage. It was decided to perform an endoscopy that showed that the leakage was about 70% of the anastomosis opening to a wound cavity of 5cm with necrotic tissue and fibrosis. Due to the clinical stability of the patient, it was decided to treat the anastomotic leakage conservatively by EVAC therapy. Results To start the EVAC therapy a polyurethane sponge was placed in the cavity via an overtube during the first endoscopy. The patient underwent a total of 14 EVAC sessions over 85 days. As we performed the sessions, healthy granulation tissue appeared leading the leakage and the cavity size to progressively improve. After the 13th session, the endoscopic evaluation showed a healed anastomosis. A CT scan with oral contrast was performed showing leak resolution. The patient started oral intake and was discharged after four days. Conclusions Treatment of anastomotic leakage after esophagectomy is still challenging and presenting high morbidity. The appropriate strategy needs to be individualized. Although surgical reintervention was the classical approach for these patients, new strategies have appeared like the EVAC. It is a promising option to improve the outcome of patients with transmural leakages who would otherwise require surgery. It has demonstrated that it is a reliable, safe and effective treatment.

Unveiling the roles of turbulence characteristics on the degradation of methylene blue by the activation of H2O2 through vortex-based hydrodynamic cavitation under neutral condition

Presently, fast degradation of organic wastewater has been achieved by the synergetic method of hydrodynamic cavitation and H2O2 at a laboratory scale, while the physico-chemical effect, especially the turbulence characteristics on the degradation process remains lacking. This paper presents investigation on the degradation of dyeing wastewater containing methylene blue (MB) under neutral condition, within a vortex-based hydrodynamic cavitation (VBHC) reactor. Operating conditions are firstly optimized and then used to collaborate with H2O2 to study the synergetic effects of this hybrid treatment method. The turbulence characteristics are subsequently obtained by a computational fluid dynamics (CFD) simulation, and the correlation between them and the degradation process of MB is revealed. The results indicate that the highest degradation rate of 91.95 % is achieved under optimal conditions. Higher inlet pressure (4.5 bar) owns the thickest vapor volume fraction, greatest vapor transfer rate, and largest size of cloud cavity in the vortex core region, indicating the strongest cavitation intensity; meanwhile, moderate solution temperature (30 ℃) also favors for the greatest cavitation intensity inside the reactor. The optimal cavitation intensity activates the considerable production of reactive oxygen species, and results in good consistency with the MB degradation performance, which predominately occurs in the annular region around the vortex rope. This research unveils the rationale behind the physical essences of the VBHC process and its influence on the degradation efficacy of MB, which can provide reliable guidance for further development of cavitational reactors to degrade organic pollutants by the VBHC/H2O2 hybrid treatment method.

Correlation between Na-Cs Ion Exchange Properties in the Alkaline Form and Acid Strength in the Proton Form of Zeolite.

The ion exchange function of zeolite is useful for such a purpose as the removal of radioactive Cs species from water. In the very early days of zeolite science, the affinity of zeolites for metal cations was explained based on geometry. After the explanation presented above was proposed, many new zeolites and related materials were discovered or synthesized. Furthermore, it has become clear that the chemical nature of the ion exchange sites is strongly dependent on the framework topology. In this study, the ion exchange behavior between Na-form zeolites with different framework topologies and Cs-containing aqueous solutions was analyzed, and the equilibrium constant was calculated based on the Langmuir type equation to investigate the influence of the chemical nature of the zeolite framework on ion selectivity. The equilibrium constants at room temperature were in the order FAU < LTA < MFI < YFI < MOR. This order is the same as the order of Bro̷nsted acid strengths in the corresponding proton form zeolites. It is suggested that the delocalization of charge around the ion exchange site stabilizes a large cation whose charge is delocalized. In contrast, the equilibrium constant was not related to the pore and cavity size. This opens new insight into the influence of the chemical nature of zeolite on the affinity to cation.