Ceramic Rings Research Articles

A multi-approach study on CO2 absorption in packed beds: Theoretical, experimental, and CFD perspectives on gas phase pulsation

This work seeks to improve CO2 absorption efficiency in packed bed columns by substituting amine-based solvents with sodium hydroxide and implementing gas phase pulsation to enhance mass transfer coefficients. Experimental analysis and computational fluid dynamics modeling were employed to investigate the impact of pulsation on absorption efficiency under various conditions. Essential parameters comprised superficial liquid velocity (1.2–4.6 cm/s), pulsation frequency (0–10 Hz), amplitude (0–20 mm), and NaOH concentration (0.25 N to 2 N), while maintaining a constant superficial gas velocity of 120 cm/s and a solute gas concentration of 13 %. Three packing materials—glass spheres, ceramic Raschig rings, and ceramic Pall rings—were evaluated. The results demonstrated that ceramic Pall rings exhibited the greatest efficiency. Pulsation, namely at 9.06 Hz and 20 mm amplitude, enhanced the volumetric mass transfer coefficient by as much as 4.53 times for Pall rings. Increased column diameters (from 7.00 cm to 11.5 cm) enhanced performance. The findings show advancement of more efficient CO2 absorption (by switching from chemical absorption using amine based solvents to classical chemical absorption using aqueous NaOH solution) for industrial applications, aiding climate change mitigation initiatives.

Effect of shaft deflection on the dynamic behaviors of the ceramic bearing rotor system within wide temperature ranges

The shaft deflection has great impact on the dynamic characteristics of the ceramic bearing rotor system, which cannot be ignored within wide temperature ranges. This paper establishes a model considering the shaft deflection, and the impact of shaft deflection appears along with changes in bearing attitude. The interaction between the various components of the bearing is recalculated, and the dynamic behavior of the full ceramic bearing rotor system in wide temperature ranges is obtained based on the thermal deformation difference. The trends of dynamic behaviors with rotor mass, rotation speed and shaft length-diameter ratio are investigated, and comparisons between simulation and experimental results are conducted for verification. It is found that the shaft deflection makes impact by bringing in extra centrifugal force, and the effects are reflected in frequency components and trajectories. The simulation results with shaft deflection fit well with the experimental results, which proves that the dynamic model considering the shaft deflection better illustrates the dynamic behavior of the ceramic outer ring when the contact situations change with working temperature. The research carries out deep insight into the running of ceramic bearing rotor system, and provides guidance for the improvement of dynamic behaviors in wide temperature ranges.

Development and Field Test of Integrated Electronics Piezoelectric Accelerometer Based on Lead-Free Piezoelectric Ceramic for Centrifugal Pump Monitoring.

In this study, an Integrated Electronics Piezoelectric (IEPE)-type accelerometer based on an environmentally friendly lead-free piezoceramic was fabricated, and its field applicability was verified using a cooling pump owned by the Korea Atomic Energy Research Institute (KAERI). As an environmentally friendly piezoelectric material, 0.96(K,Na)NbO3-0.03(Bi,Na,K,Li)ZrO3-0.01BiScO3 (0.96KNN-0.03BNKLZ-0.01BS) piezoceramic with an optimized piezoelectric charge constant (d33) was introduced. It was manufactured in a ring shape using a solid-state reaction method for application to a compression mode accelerometer. The fabricated ceramic ring has a high piezoelectric constant d33 of ~373 pC/N and a Curie temperature TC of ~330 °C. It was found that the electrical and physical characteristics of the 0.96KNN-0.03BNKLZ-0.01BS piezoceramic were comparable to those of a Pb(Zr,Ti)O3 (PZT) ring ceramic. As a result of a vibration test of the IEPE accelerometer fabricated using the lead-free piezoelectric ceramic, the resonant frequency fr = 20.0 kHz and voltage sensitivity Sv = 101.1 mV/g were confirmed. The fabricated IEPE accelerometer sensor showed an excellent performance equivalent to or superior to that of a commercial IEPE accelerometer sensor based on PZT for general industrial use. A field test was carried out to verify the applicability of the fabricated sensor in an actual industrial environment. The test was conducted by simultaneously installing the developed sensor and a commercial PZT-based sensor in the ball bearing housing location of a centrifugal pump. The centrifugal pump was operated at 1180 RPM, and the generated vibration signals were collected and analyzed. The test results confirmed that the developed eco-friendly lead-free sensor has comparable vibration measurement capability to that of commercial PZT-based sensors.

Innovative approaches for enhanced nutrient (N and P) removal and biosecurity in marine recirculating aquaculture systems using biofloc and ultrafiltration combined systems

Marine recirculating aquaculture systems (marine RAS) are increasingly utilized for their high productivity and minimal environmental impact. However, effective nutrient management and biosecurity measures remain crucial for sustainable operation of marine RAS. This study successfully established a simultaneous nitrification and denitrification (SND) process using a biofloc technology (BFT)–ultrafiltration (UF) combined approach. A stable autotrophic marine nitrification system was rapidly initiated within 23 days using a ceramic ring (CR)–granular activated carbon (GAC)–UF process (CGUF), followed by the substitution of polyhydroxyalkanoates (PHA) for GAC filter to achieve rapid start-up of SND in 24 h (CG/PUF). Soluble reactive phosphate (SRP) was removed in-situ via biofloc adsorption. The co-existence of ammonia-oxidizing archaea (Candidatus_Nitrosopumilus) and denitrifying bacteria (Stenotrophomonas, Ruegeria and Ilumatobacter) synergistic promoted the SND start-up in CG/PUF process. Stenotrophomonas emerged as the keystone species which closely linked to amoA/B/C, hao and nosZ genes (p < 0.05). The CG/PUF process effectively enhanced the biosecurity of marine RAS, with 100 % elimination of potential pathogens (Vibrio and Tenacibaculum). UF membrane could maintain fluxes at 15 L∙ m−2∙ h−1 (LMH) for 180 days, with a 2-day intermittent hydraulic flushing keeping transmembrane pressure below 50 kPa. These findings provide insights for broader application of BFT–UF combined process in marine RAS.

Finite element analysis of a Helmholtz transducer jointly driven by a trilaminar ring and a piezoelectric circular tube

Abstract Crosswell seismic survey can image the crosswell geological anomalies with high resolution in 3D. To effectively conduct crosswell seismic survey, it is necessary to use a seismic source capable of transmitting low-frequency and high-power signals in a compact size. In this paper, a novel Helmholtz transducer is proposed, which utilizes both the bending vibrations of the trilaminar ring and the radial vibrations of the piezoelectric circular tube to simultaneously drive the vibration of the Helmholtz liquid cavity. This design reduces the resonant frequency of the liquid cavity while enhancing the transmitting voltage response at the liquid cavity resonant frequency. The influence of the inner radius of the trilaminar ring, the outer radius of the ceramic ring and the length of the piezoelectric circular tube on the liquid cavity resonant frequency and the transmitting voltage response at the liquid cavity resonant frequency is simulated using the finite element method. The simulation results provide a theoretical foundation for optimizing the design of such transducers.

A 2.8 W Single-Frequency Laser Output at 1064 nm from a Gradient-Doped Composite Ceramic Non-Planar Ring Oscillator

A 2.8 W Single-Frequency Laser Output at 1064 nm from a Gradient-Doped Composite Ceramic Non-Planar Ring Oscillator

Simulation study on acoustic performance of Tonpilz piezoelectric transducers

Abstract The Tonpilz configuration of transducers is recognized for its capability to generate high-power acoustic emissions at relatively lower frequencies, which is a prevalent setup in sonar systems. Comprising a frontal radiating element, a rear casing, and a piezoelectric ceramic ring sandwiched between them and affixed by a central bolt, this study delineates the inclusion of bolt pretension impact. The investigation assesses the structural and acoustic ramifications of the transducer’s frequency response. These findings indicate the commendable acoustic performance of the transducer.

A Timoshenko-Ehrenfest beam model for simulating Langevin transducer dynamics

The Langevin transducer is a widely used power ultrasonic device across both medical and industrial applications, from orthopaedic surgery to drilling and welding. It is a sandwich-type device which typically consists of piezoelectric ceramic rings between two metallic end-masses. The transducer is commonly operated at a particular resonant mode to deliver ultrasonic vibrations to a target structure of interest, and is generally modelled using approaches including the transfer matrix method and electromechanical equivalent circuit methods. Here, we propose a variational framework to study the dynamics of the Langevin transducer based on the Timoshenko-Ehrenfest beam theory and Hamilton's principle. The variational equation derived from this model is then discretized by the standard finite element method with spectral elements. To verify the proposed one-dimensional electromechanical model, the computed resonance frequencies, or natural frequencies, of the one-dimensional model are compared to those of a three-dimensional finite element model with respect to varying geometry parameters characterizing the transducer. The results of the reduced one-dimensional and full three-dimensional models are then compared to those measured through an experimental investigation consisting of laser Doppler vibrometry. This is undertaken for the first ten eigenfrequencies, including longitudinal and bending modes, where normalized amplitudes and vibration mode shapes are reported. The close correlation between modelling and experiment demonstrates that the proposed one-dimensional electromechanical model can deliver results consistent with the full three-dimensional model and from experiment, thus verifying a rapid and reliable method for studying the free vibrations and dynamics of the Langevin transducer which accounts for the axial vibrations of the piezoelectric ceramic stack in all cases.

The Study of Semi-Continuous Chemical Physical Treatment System for Pollutant Removal in Palm Oil Mill Effluent

Effluent from palm oil mill processing is a major concern due its properties and characteristics that highly contributed to water pollution. This study reported on POME treatment by a semi-continuous treatment system consisting of coagulation, sedimentation and filtration processes in the presence of a by-product coagulant (copperas combined with lime). The treatment was conducted for different types of filter medias (FMs): a) FM 1: sand+activated carbon and b) FM 2: sand+ceramic ring) and various retention times (RT) from 1/2 to 2 h. The treatment resulted in different removal efficiencies of turbidity, colour, chemical oxygen demand (COD) and total suspended solids (TSS) for secondary and tertiary POME samples. With semi-continuous treatment, the pollutants in the secondary POME sample decreased, resulting in the removal efficiency of 57.34% for turbidity, 95.16% for colour, 82.08% for COD and 83.23% for TSS. Meanwhile, the results of the tertiary sample were 54.81%, 81.08%, 78.05% and 68.51% for turbidity, colour, COD and TSS removal respectively. The statistical analysis of ANOVA (p-value&lt;0.05) indicated that the data was statistically significant with the FM 1 as a media filter. As a result, a semi-continous chemical-physical treatment system may provide information in efficient POME treatment.

The influence of thermal expansion of carbon-carbon composite materials on the stability of their tribological parameters

The influence of thermal expansion of disk specimens made of carbon-carbon composite materials on the stability of their tribological characteristics in a friction pair with a ceramic ring counterbody is studied theoretically and experimentally. The temperature characteristics of composites with two different structures — fibrous and fabric — are studied. The experimental dependences of the load change on time during frictional heating are compared with the calculation model obtained by methods of contact interaction mechanics. A relation is established between changes in interface stiffness and the dependence of the coefficient of thermal expansion on temperature for the materials under study. Uneven wear of the fabric composite is revealed at the initial stage with destruction of fabric layers and tearing out of structural components. Keywords:carbon-carbon composite material, contact interaction, friction, temperature, frictional heating, coefficient of thermal expansion, wear ivan.yu.tsukanov@gmail.com, lyubicheva@mail.ru, bukovskiy.pavel@gmail.com

Biogas production by integrating lava rock, red clay & ceramic bio ring as support carrier in treatment of landfill leachate with liquidised food waste

To evaluate the feasibility of co-digestion of landfill leachate and liquidised food waste, batch experiments were conducted to explore the optimal mixing ratio and support carrier integration in up-flow anaerobic sludge blanket reactors. Continuous experiments were conducted to evaluate the long-term effects of support carriers on methane generation and digestate characteristics. To compare biogas accuracy, Biomethane Potential Tests 1 and 2 data were used to build artificial neural networks using feed-forward backpropagation and support vector machines using linear function. Red clay bio ring, ceramic bio ring and lava rock support carriers were used in the modified reactors. Significant improvement in the anaerobic process was observed during the co-digestion, along with the addition of a ceramic bio ring with biogas production (2150 mL/d), specific methane production (293.30 mL CH4/gCODadded, >66.10% compared to the conventional reactor), and chemical oxygen demand removal (>80%) at an organic loading rate of 6 g/L/day. The Brunauer-Emmett-Teller method demonstrates that ceramic bio ring has a higher specific surface area (7.87 m2/g). The support vector machine model had superior predicted accuracy in biogas production with an R2 of 0.986, indicating it is more robust for large-scale applications. Thus, utilising a suitable proportion of substrates and selecting an appropriate support carrier can stimulate methanogenic activity, which can boost methane production, a promising renewable energy source, and produce higher-quality effluent.

Fabrication and Electrical Properties of PSZT Piezoelectric Ceramic Ring for Ultrasonic Welding Application

Fabrication and Electrical Properties of PSZT Piezoelectric Ceramic Ring for Ultrasonic Welding Application

Non-invasive temperature measurement in fixed bed reactors using RFID technology

Measuring axial temperature profiles in fixed bed reactors is essential for an optimal and safe operation. Typically, thermocouples are used which influence the bed structure - especially in arrangements with a low ratio between tube and particle diameter - and thus local transport phenomena and reaction rates. In this publication, Radio-Frequency Identification (RFID) tags are used for temperature measurement in fixed beds without disturbing the bed structure. Therefore, the temperature is compared in a tubular fixed bed (▪) of ceramic rings (▪) measured with RFID tags and thermocouples at similar axial positions at different temperature levels 20<T<140▪. By integrating an RFID tag into a particle using 3D printing, the disturbance of the fixed bed by the measurement device can be even completely avoided. It is shown that the overall values of temperature and the dynamic measurement with RFID tags is comparable to measurements using thermocouples. However, significant measurement gaps can occur, especially with unfavorable antenna-tag alignment or small antenna spacing. As a summary, it is possible to measure temperature in fixed bed reactors using RFID technology without requiring direct access and thus disturbing the bed structure. Finally, current shortcomings of RFID are discussed, and research needs presented.

RETRACTED: Enhanced biofiltration coupled with ultrafiltration process in marine recirculating aquaculture system: Fast start-up of nitrification and long-term performance

In marine recirculating aquaculture systems (RAS), the biological nitrification system usually suffers from long time start-up and proliferation of potential pathogenic bacteria under the high salinity stress. This study aims to develop a strategy for fast start- up and long-term biosecurity of marine RAS by using a combined biofiltration system (ceramic rings (CR) - granular activated carbon (GAC) - ultrafiltration (UF) process) in an actual marine RAS for selenotoca multifasciata. The ammonia nitrogen and dissolved organic matter (DOM) removal performance, membrane fouling characteristics and microbial communities during long-term operation (200 days) were investigated. The CR-GAC-UF process minimized the start-up time of the nitrification system to 14 days under low ammonia concentrations (below 2 mg/L). Long-term operation of the marine RAS with ammonia and nitrite nitrogen stabilized below 0.1 mg/L with a daily ammonia nitrogen removal rate of 91.7 %. The UF membranes were operated at fluxes at 15 LHM and the protein/polysaccharide ratios of soluble microbial products (SMP) and extracellular polymeric substances (EPS) on the membranes were stable below 0.5 with low fouling levels. A number of bacterial genera that have the potential to degrade protein and humic-like substances were recognized, which was related to the long-term DOM removal. Candidatus_Nitrosopumilus, Nitrosomonas_sp. and Nitrospira sp. ENR4 were detected as the core nitrifiers in CR-GAC-UF process, which were closely related to the amoABC, hao and nxrA genes (p < 0.05). With the multi-stage barrier of CR-GAC-UF, the heterotrophic plate count in therecirculating water was kept at 3 ± 1 CFU/mL and the relative abundance of potential pathogens declined gradually below 0.81 %. Taken together, this study provides a theoretical basis for the wider application of marine RAS.

Evaluating CO2 desorption performance of MEA solution with MnOx/HZ catalytic packings by visualization method

The high energy consumption in the CO2 desorption process is one of the main issues of the chemical absorption method. To address this issue, a MnOx modified HZSM-5 catalyst (MnOx/HZ) was prepared by impregnation method and used as catalytic packing to improve the CO2 desorption rate in the monoethanolamine (MEA) solution. Since the catalytic effects mainly work around the catalytic packing, a visualization method, which can measure the CO2 desorption rate per unit surface area (vCO2/area) of a single packing, is proposed to avoid some uncertain effects occurring as the conventional bubbling method is used. The results showed that the vCO2/area of the MnOx/HZ catalytic packing is 10.06 μmol·cm−2·s−1 at 80 °C, which is 1.78 times of that of HZSM-5 and 15 to 60 times of that of commercial packings. Actually, the MnOx/HZ has more Brønsted and Lewis acid sites than HZSM-5 according to the pyridine adsorption infrared spectroscopy (Py-IR) characterization. As a result, the apparent activation energy (Ea) of the CO2 desorption reaction with the addition of MnOx/HZ can be reduced by 58.6% and 18% compared with the addition of ceramic saddle ring packing and HZSM-5, respectively. However, the catalytic performance of MnOx/HZ packings degrades gradually due to the blockage of micropores by the reaction product, that needs to be settled in the future.

Measurement and optimization of the beam coupling impedance of a novel 3D-printed titanium alloy cage inside the thin-wall vacuum chamber.

Dipole magnet vacuum chambers are among the most critical and costly components of rapid-cycling accelerator facilities. Alternative approaches to traditional ceramic chambers have been explored for the implementation of fast-ramping dipole-magnet vacuum chambers, including thin-wall metallic beam pipe chambers strengthened with transverse ribs and ceramic rings inside thin-walled chambers. Here, we report a novel 3D-printed titanium alloy cage inside the thin-wall vacuum chamber, which is designed for high-intensity heavy ion accelerator facility (HIAF) to reduce manufacturing difficulty and cost, shorten the production cycle, and improve the quality. Comprehensive studies were undertaken to characterize the impedance of the 3D-printed titanium alloy cage inside the thin-wall vacuum chamber. The beam-coupling impedance and eddy currents of the new thin-wall vacuum chamber were studied mostly numerically. Strategies for further reducing the beam-coupling impedance were explored. In addition, impedance bench measurements using the "half wavelength" resonant method were conducted to identify the longitudinal and transverse impedances of the 3D-printed titanium alloy cage inside the thin-wall vacuum chamber prototype experimentally. The simulated and measured results for the impedance were consistent. Furthermore, a campaign for resonance-check measurements on the 3D-printed titanium alloy ring loaded inside a thin-wall vacuum chamber prototype was launched. This novel thin-wall vacuum chamber structure is now entering the fabrication stage and will soon be ready for installation in the Booster Ring (BRing).

Efficient reforming of methane in a porous radiant reactor with regular structure: A novel experimental system for heat-hydrogen coproduction

As a high-energy clean fuel, hydrogen is one of the most promising energy carriers to achieve “carbon neutrality”. In order to produce hydrogen, a novel porous media heat-hydrogen coproduction system (PHH) with regular structure was built, and ceramic foam was added to improve thermal radiation performance. The effects of porous regular structure on the temperature distribution, products concentration, and thermal radiation efficiency were investigated at different operating conditions. The results indicated that the regular structure achieved higher hydrogen concentration and methane conversion efficiency than the irregular structure, especially at small-diameter pellets. Meanwhile, increasing the pellets diameter and decreasing the ceramic rings size reduced the radiation efficiency, but that improved the hydrogen production. The optimal thermal efficiency (26.5%) and radiation efficiency (33.2%) were obtained in the Ⅰ-type reactor at the equivalence ratio of 1.5. In addition, with the inlet velocity increasing from 10 to 14 cm/s, the combustion temperature and syngas energy conversion efficiency significantly increased. These results provide an essential reference for advancing the practical application of heat-hydrogen coproduction and the design of the regular structure in porous media reactor.

Mechanical performance evaluation and structural optimization of ceramic lined thin-walled vacuum chambers

Thin-walled vacuum chamber internally supported by ceramic spacers is a promising approach to provide sufficiently robust, ultra-high vacuum compatible and low gap vacuum devices for high energy, high current, heavy ions accelerators. The mechanical performance of the ring shaped ceramic spacers is a key factor in the structural design of these vacuum chambers. An extensive campaign was devoted to develop methodologies and equipment for evaluating the mechanical and structural properties of the ceramic spacers and to optimize the chamber design. To this aim, a force analysis on single ceramic rings was first conducted, and formulas for calculating the elastic modulus and bending strength of the ceramic rings were derived. The elastic modulus and critical position strength limits of alumina and zirconia ceramic rings were tested using a mechanical testing platform. Based on the test results of a single ceramic ring, a preliminary design and processing of ceramic lined thin-walled vacuum chamber test samples was finalized. A testing device capable to apply known water pressure values was then designed and built to test the chamber ability to withstand externally applied forces and measure the mechanical parameters of the ceramic spacers. Thanks to this, the acceptable stress limits of alumina and zirconia ceramic rings as the supporting components of the vacuum chamber were obtained. Knowing these values, through an iteration process, the whole design and properties of the ceramic lined thin-wall vacuum chamber was optimized. Finally, to reduce the impact of eddy current heat effect on ceramic strength and outgassing, a suitable cooling structure was designed and implemented.

A Cu-based ceramic porous abrasive ring with phyllotactic pattern in internal cooling grinding of Inconel 718

A Cu-based ceramic porous abrasive ring with phyllotactic pattern in internal cooling grinding of Inconel 718

Lead-Free Piezoelectric Acceleration Sensor Built Using a (K,Na)NbO3 Bulk Ceramic Modified by Bi-Based Perovskites

Piezoelectric accelerometers using a lead-free (K,Na)NbO3 (KNN) piezoceramic modified by a mixture of two Bi-based perovskites, Bi(Na,K,Li)ZrO3 (BNKLZ) and BiScO3 (BS), were designed, fabricated and characterized. Ring-shaped ceramics were prepared using a conventional solid-state reaction method for integration into a compression-mode accelerometer. A beneficial rhombohedral-tetragonal (R-T) phase boundary structure, especially enriched with T phase, was produced by modifying intrinsic phase transition temperatures, yielding a large piezoelectric charge coefficient d33 (310 pC/N) and a high Curie temperature Tc (331 °C). Using finite element analyses with metamodeling techniques, four optimum accelerometer designs were obtained with high magnitudes of charge sensitivity Sq and resonant frequency fr, as evidenced by two key performance indicators having a trade-off relation. Finally, accelerometer sensor prototypes based on the proposed designs were fabricated using the KNN-BNKLZ-BS ceramic rings, which exhibited high levels of Sq (55.1 to 223.8 pC/g) and mounted fr (14.1 to 28.4 kHz). Perfect charge-to-acceleration linearity as well as broad flat frequency ranges were achieved with excellent reliability. These outstanding sensing performances confirm the potential application of the modified-KNN ceramic in piezoelectric sensors.