Measurement of Flow Characteristics in a Bubbling Fluidized Bed Using Electrostatic Sensor Arrays

Fluidized beds are widely applied in a range of industrial processes. In order to maintain the efficient operation of a fluidized bed, the flow parameters in the bed should be monitored continuously. In this paper, electrostatic sensor arrays are used to measure the flow characteristics in a bubbling fluidized bed. In order to investigate the electrostatic charge distribution and the flow dynamics of solid particles in the dense region, time and frequency domain analysis of the electrostatic signals is conducted. In addition, the correlation velocities and weighted average velocity of Geldart A particles in the dense and transit regions are calculated, and the flow dynamics of Geldart A and D particles in the dense and transit regions are compared. Finally, the influence of liquid antistatic agents on the performance of the electrostatic sensor array is investigated. According to the experimental results, it is proved that the flow characteristics in the dense and transit regions of a bubbling fluidized bed can be measured using electrostatic sensor arrays

Theoretical and experimental methods of dynamic clothing pressure performance

A dynamic pressure measuring system has been developed in this study. This system can be used for static pressure measuring, real-time dynamic pressure measuring and pressure fatigue analysis. A 3D geometric model on fabric deformation as well as mechanical behavior has been developed, which can be used for simulating the fabric elongation during dynamic pressing, and to deduce relationship between the press depth and fabric elongation. The process parameters of measuring system have been systematically estimated and analyzed. The range of press depth fixed for dynamic pressure measurement is found to be 58-115 mm, which responds to the fabric elongation from 10% to 40%. The press velocity at 100 mm/min is considered as the optional one for dynamic pressure measurement. Five repeated test cycles can be satisfied to assess the dynamic pressure fatigue performance quickly

Experimental study of bubble dynamics and flow transition recognition in a fluidized bed with wet particles

This paper studies the bubble dynamics and flow transition behavior in wet particle systems. Non-coherent algorithm was used to quantitatively calculate the bubble diameters in a three-dimensional fluidized bed system loaded with wet particles, obtaining the bubble dynamics under the action of liquid. The results indicate that the incoherent analysis can detect the formation of even tiny bubbles in the fluidized bed. The kurtosis and skewness of the pressure fluctuation signal was used to obtain the critical transition conditions of the flow pattern from turbulent to laminar. Through the decay index of the incoherent spectrum, the operating conditions of the Levy-Kolmogorov flow pattern to the Kolmogorov flow region were determined. From the comparison of the liquid bridge and the drag forces, the competitive mechanism of different forces acting on the particles that conformed the bed was analyzed, reflecting the change of the apparent minimum fluidization velocity of wet particles

Strategy for Mitigating Antibiotic Resistance by Biochar and Hyperaccumulators in Cadmium and Oxytetracycline Co-contaminated Soil

Publisher Copyright: © 2021 The Authors. Published by American Chemical SocietyThe global prevalence of antibiotic resistance genes (ARGs) is of increasing concern as a serious threat to ecological security and human health. Irrigation with sewage and farmland application of manure or biosolids in agricultural practices introduce substantial selective agents such as antibiotics and toxic metals, aggravating the transfer of ARGs from the soil environment to humans via the food chain. To address this issue, a hyperaccumulator (Sedum plumbizincicola) combined with biochar amendment was first used to investigate the mitigation of the prevalence of ARGs in cadmium and oxytetracycline co-contaminated soil by conducting a pot experiment. The addition of biochar affected the distribution of ARGs in soil and plants differently by enhancing their prevalence in the soil but restraining transmission from the soil to S. plumbizincicola. The planting of S. plumbizincicola resulted in an increase in ARGs in the soil environment. A structural equation model illustrated that mobile genetic elements played a dominant role in shaping the profile of ARGs. Taken together, these findings provide a practical understanding for mitigating the prevalence of ARGs in this soil system with complex contamination and can have profound significance for agricultural management in regard to ARG dissemination control.Peer reviewe

Cloning and Functional Analysis of the MADS-box CiMADS9 Gene from Carya illinoinensis

AbstractA MADS-box gene, CiMADS9, was cloned from the male flowers of Carya illinoinensis by rapid amplification of cDNA ends. The gene was 1 077bp with a 768bp open reading frame encoding 255 amino acids. Multiple sequence comparisons revealed that CiMADS9 is a typical MIKC-type MADS-box gene with a MADS-box domain and a K semi-conserved region. Phylogenetic analysis indicated that CiMADS9 belongs to the AGL15 group of the MADS-box gene family. Quantitative reverse transcription polymerase chain reaction analysis indicated that the expression levels in reproductive organs (i.e., flowers and young fruits) were considerably higher than in vegetative tissues (i.e., leaves and branches). The highest expression levels were observed in male flowers. An overexpression vector for CiMADS9 was constructed and the gene was inserted into the Arabidopsis thaliana genome. CiMADS9 expression was confirmed in all transgenic lines. Compared with wild-type plants, transgenic A. thaliana plants overexpressing CiMADS9 exhibited delayed flowering and an increased number of leaves

3D-printed custom implant for the management of “locked” posterior dislocation of the shoulder joint with reverse Hill-Sachs lesion: a case report

Introduction: Irregular bone defects of the humerus are common in clinical practice, but there are fewer reported cases of irregular humeral defects accompanied by shoulder joint “locking” dislocation and reverse Hill-Sachs injury caused by an electric shock. The choice of treatment for such cases is closely related to the extent of shoulder joint function recovery. This is a case report of a 60-year-old male patient who suffered from a shoulder joint “locking” dislocation with accompanying reverse Hill-Sachs injury due to muscle contraction after being electrically shocked at work. The patient was treated with a 3D-printed custom humeral head prosthesis for the treatment of the shoulder joint “locking” dislocation and reverse Hill-Sachs injury.Case presentation: A 60-year-old male patient, working as a construction worker, presented to our emergency department with right shoulder pain and restricted movement for more than 30 min after an electric shock. Right humeral CT revealed a comminuted fracture of the right humeral head. D-dimer levels were significantly elevated at 3239.00 ng/mL, and oxygen partial pressure was slightly decreased at 68 mmHg. Treatment included emergency wound debridement and dressing for the electrical injury, cardioprotective measures, anticoagulation, and symptomatic management. After stabilizing the patient’s condition, the patient underwent 3D-printed custom prosthesis-assisted partial replacement of the right humeral head and rotator cuff repair in the orthopedic department. Postoperatively, the patient’s right shoulder joint wound healed well, and mobility was restored.Conclusion: This case report demonstrates that the use of a 3D-printed custom prosthesis for the treatment of irregular humeral bone defects caused by specific injury mechanisms, especially cases involving shoulder joint “locking” dislocation and reverse Hill-Sachs injury, can achieve precise bone defect repair, minimize surgical trauma, and provide superior outcomes in terms of postoperative functional rehabilitation

Simultaneous measurement of electrostatic charge and its effect on particle motions by electrostatic sensors array in gas-solid fluidized beds

Repeated particle-particle and particle-wall collisions and frictions lead to the generation and accumulation of electrostatic charges in the gas-solid fluidized beds. Variations of electrostatic signals are a rich source of information on particle motions and charging, which have rarely been explored and interpreted. To gain a more comprehensive understanding of the induced electrostatic signals in the fluidized beds, an array of arc-shaped induced electrostatic sensors were attached to the outer wall of a fluidized bed. Combined with cross-correlation method, induced electrostatic voltage signals and correlation velocity of particles were measured simultaneously. It was found that electrostatic charges accumulation restrained the particle motions while the average correlation velocity of particles increased with the amount of injecting liquid antistatic agent. Based on the analyses of induced electrostatic signals, the particle correlation velocity, and the particles charge-to-mass ratio under different charging levels, a predictive model of the average particles charge-to-mass ratio was established. Compared with the results obtained from Faraday cup, the estimated results showed a relative error no more than 40%. Simultaneous measurement of particle correlation velocity and particles charge-to-mass ratio were complemented by arc-shaped induced electrostatic sensors array combined with cross-correlation method

Monitoring of particle motions in gas-solid fluidized beds by electrostatic sensors

Gas-solid fluidized beds are widely applied in numerous industrial processes. Particle motions significantly affect the performance of fluidized bed reactors and the characterization of particle movements is therefore important for fluidization quality monitoring and scale-up of reactors. Electrostatic charge signals in the fluidized bed contain much dynamic information on particle motions, which are poorly understood and explored. In this work, correlation velocities of Geldart B and D particles were measured, analyzed and compared by induced electrostatic sensors combined with cross-correlation method in the fluidized bed. The results indicated that the average correlation velocity of particle clouds increased and the normalized probability density distributions of correlation velocities broadened when the superficial gas velocity increased in the dense-phase region. Both upward and downward correlation velocities could be acquired in the dynamic bed level region. Under the same excess gas velocity, the average correlation velocity of Geldart D particles was significantly smaller than that of Geldart B particles, which was caused by the smaller bubble sizes caused by the dominant bubble split over coalescence and less volume of gas forming bubbles for Geldart D particles. The experimental results verified the reliability and repeatability of particle correlation velocity measurement by induced electrostatic sensors in the gas-solid fluidized bed, which provides definite potential in monitoring of particle motions