Transducer Technique Research Articles

Impact of Device Trajectory and Device Type on Compression During Simulated Bone Resorption in a Subtalar Model

Introduction/Purpose: Despite the prevalence of subtalar arthrodesis, certain risk factors (smoking, diabetes) diminish fusion outcomes and are associated with decreased bone healing, leading to increased duration of high stresses at the bone/device interface, ultimately leading to loosening/loss of compression. Existing fixation devices using static engineering materials (i.e., titanium) falter when postoperative bone resorption/joint-settling occurs, justifying improved fixation devices that drive continuous compression in the setting of bone resorption. Devices that leverage superelastic properties of NiTiNOL can provide sustained dynamic compression in the setting of bone resorption, ideally positioning them for these patient populations. Thus, the goal of this study was to characterize the biomechanical response of static and dynamic (NiTiNOL) devices across multiple trajectories in subtalar arthrodesis in the setting of simulated bone resorption. Methods: Compressive forces between synthetic talus and synthetic calcaneus (Sawbones) were measured for two commercially available orthopedic fixation devices (Dynamic = 7.0mm dia. 90mm length, Static = 7.0mm dia; 90mm length, N =6/group) in a custom subtalar fixture. The devices were inserted according to manufacturer instructions (FigA) while maintaining a gap between bone segments using a removable spacer. Two devices were inserted within each group (Dynamic, Static, Static+Dynamic) in either a parallel or diverging trajectory (FigA). Following insertion of devices, the spacer was removed enabling measurement of initial compression (Transducer Techniques). Subsequently, the bones were allowed to move into apposition while continued measurements of compression were collected, enabling determination of resorption capacity (distance) prior to loss of compressive force. Data were analyzed using a two-way ANOVA with Tukey post hoc test (α=.05). Results: The Dynamic group exhibited significantly increased initial load as compared to the Static and Static + Dynamic groups in both the parallel and diverging trajectories (FigB, p=.031). The initial load provided by the first device in the Dynamic group was significantly increased as compared to the Static group (FigB, p=.030). The Dynamic group exhibited a significant increase in initial load upon insertion of the second device (FigB, p Conclusion: Generating and maintaining sufficient compression is requisite for successful subtalar arthrodesis outcomes, especially in the presence of bone resorption. These data illustrate the significant increase in both initial load and resorption capacity of the sustained dynamic compression device (Dynamic) as compared to the Static and Static + Dynamic groups. The addition of a second Dynamic device markedly increased the compression, whereas the use of static devices prevented generation of increased compressive forces. Device trajectory did not significantly impact the arthrodesis construct biomechanical performance. One dynamic screw has better biomechanical performance than two static screws. Figure A) Illustration of guide wire placements prior to device insertion. B) Initial load generated between boney segments. C) Resorption distance prior to loss of compression.

An Online Monitoring Method for High- Temperature Environments Combining Eddy Current Testing and Electromagnetic Acoustic Transducer Techniques

An Online Monitoring Method for High- Temperature Environments Combining Eddy Current Testing and Electromagnetic Acoustic Transducer Techniques

Investigating the relationship between quantitative-based ultrasound and MRI estimations of rotator cuff fatty infiltration.

Fatty infiltration (FI) of the rotator cuff has important clinical implications. Quantitatively estimating FI using ultrasound (US) has considerable benefits for assessing FI in a non-invasive, accessible manner. This research investigated whether FI of the supraspinatus (SS) and infraspinatus (IS), estimated using US was related to intramuscular fat fractions measured from magnetic resonance images (MRI). Data from 12 healthy young adult participants were used for analysis. US images of the SS and IS were captured using multiple transducer placement techniques from which echogenicity of the muscle region was quantified. Shoulder MRI were captured from which SS and IS were manually segmented and intramuscular fat fractions calculated. Six upper limb strength exertions were performed, resisted by a hand dynamometer. IS and SS echogenicity explained a significant amount of variance in MRI fat fractions for certain body positions and transducer techniques. Echogenicity agreement was higher for IS than SS. Significant relationships were identified between strength exertions and both echogenicity and MRI muscle volume, but not MRI fat fraction. This research provides preliminary evidence showing that quantitative-based US methods can be used to estimate MRI calculated fat fractions for the rotator cuff.

In-Motion Railcar Wheel Inspection using Magnetostrictive EMATs

Due to cyclic mechanical loading, railcar wheels are subject to the development of internal fatigue cracks in the rim underneath the tread surface. Off-line inspections are extremely laborious and require extended out-of-service time, and most existing in-line inspection systems that use conventional ultrasonics or electromagnetic acoustic transducer (EMAT) techniques have several drawbacks that limit their full-scale deployment in service. This paper discusses the work performed on the initial research and development of a proof-of-concept novel magnetostrictive EMAT sensor for in-motion railcar wheel inspection. Wheelsets with known internal discontinuities and a 3.7 m long panelized track were used to demonstrate the feasibility of the developed approach and methods. The results obtained from these tests have shown that the magnetostrictive EMAT sensor that generates 5 mm wavelength shear horizontal waves detects both surface defects and internal fatigue cracks with an excellent signal-to-noise ratio. Different wavelengths can also be added to the sensors to enhance or complement the detection of fatigue cracks at different depths. A total of four or five sensors located at standard concrete crosstie spacing along each rail would be able to provide complete coverage on wheels ranging from 711 to 965 mm in diameter with ±90° wheel coverage per sensor, and a theoretical inspection speed of 56 kph can be achieved using this approach.

Nucleic Acid Aptamer-Based Biosensors: A Review.

Aptamers, short strands of either DNA, RNA, or peptides, known for their exceptional specificity and high binding affinity to target molecules, are providing significant advancements in the field of health. When seamlessly integrated into biosensor platforms, aptamers give rise to aptasensors, unlocking a new dimension in point-of-care diagnostics with rapid response times and remarkable versatility. As such, this review aims to present an overview of the distinct advantages conferred by aptamers over traditional antibodies as the molecular recognition element in biosensors. Additionally, it delves into the realm of specific aptamers made for the detection of biomarkers associated with infectious diseases, cancer, cardiovascular diseases, and metabolomic and neurological disorders. The review further elucidates the varying binding assays and transducer techniques that support the development of aptasensors. Ultimately, this review discusses the current state of point-of-care diagnostics facilitated by aptasensors and underscores the immense potential of these technologies in advancing the landscape of healthcare delivery.

Evaluation of bonding techniques for ultrasound transducers

Development of ultrasound transducers for operation in high pressure and high temperature environments is still a challenge. This paper presents an evaluation of different bonding techniques for ultrasound transducers intended for harsh environments. Performance at temperature 180 °C was investigated at atmospheric pressure, and performance under hydrostatic pressure 1000 bar was investigated at temperature 15 °C. Five different bonding configurations were tested, two polymer adhesives and three metallurgical bonding methods. One of the polymer adhesives is a standard epoxy-adhesive, the other is an adhesive intended for operation at high temperatures. Two of the metallurgical bonding configurations studied are Solid-liquid Interdiffusion (SLID) bonds. The third metallurgical bonding method introduces preform soldering as a new bonding technique for ultrasound transducers. All the metallurgical bonding methods outperform polymer adhesives in shear strength and temperature stability. Compared to the SLID-methods, preform-soldering offers a faster and cheaper bonding process without the need for electroplating, making it an attractive metallurgical bonding technique for ultrasound transducers.

Biomedical applications of smartphone-based lateral flow detection systems as a diagnosis tool

Smartphone-based devices show the capability to be the main biomedical diagnosis device, enabling persons to perform for self-screening tests. In the healthcare, smartphone-based devices are reforming patient care and management. However, there are some important issues relating to the reliability of the fabricated probes which must be improved to be utilized as the main detection probes. This review discussed the applications smartphone-based lateral flow assay (LFA) devices in the detection of biomolecules, focusing on the analytical performance and probe signal transducing techniques. Also, this review discloses the technology gaps of the smartphone-based LFA system such as the need to fabricate more sensitive light image lens and better interface to transduce the signal intensity to the digits in the completed whole blood media to obtain reliable results. Addressing the benefits and limitations motivates investors to prioritize the development of potent smartphone-LFAs for personalized medicine.

A hybrid nondestructive testing method of pulsed eddy current testing and electromagnetic acoustic transducer techniques based on wavelet analysis

It is found that the electromagnetic acoustic testing (EMAT) signal itself contains part of the pulsed eddy current testing (PECT) signal. Therefore, if the pulsed eddy current signal embedded in the electromagnetic ultrasound signal can be effectively extracted and used, the hybrid nondestructive testing method of electromagnetic ultrasound and pulsed eddy current can be truly realized. Based on the above concept, the authors have obtained some preliminary results through simple signal processing try, and which gave us a promising hope of this hybrid method. To further verify the validity and strengthen the usability of the hybrid method, more effective signal separation and extraction way to the hybrid detection signals is expected, which is the core step. In this study, a new signal separation and extraction method is proposed for the hybrid detection signals in the PECT/EMAT nondestructive testing method based on wavelet analysis strategy. The effectiveness and merits of the proposed signal separation method compared to the previous way is verified through the numerical simulation as well as experiment.

Point of Care Ultrasound (POCUS) Utilization and Barriers by Senior Emergency Medicine and Critical Care Residents at Two Teaching Referral Hospitals, Addis Ababa, Ethiopia.

POCUS has become an integral part of the practice of emergency medicine. POCUS is a highly focused, limited, goal-directed exam with the expressed purpose of answering selected questions used at the bedside for critically ill patients who are not stable. We aimed to assess POCUS utilization and barriers by senior-year emergency medicine and critical care residents at two tertiary academic and referral hospitals in Addis Ababa, Ethiopia. Methodology. A cross-sectional study was conducted from June 1 to August 30, 2022 in St Paul's Hospital Millennium Medical College and Tikur Anbessa Specialized Hospital using an electronic survey of senior-year (second and third years) emergency medicine and critical care residents. Data were collected using Goggle form, exported to SPSS version 24, and then analyzed. Seventy-six residents out of 78 (97.4%) responded to the online survey. The mean age was 29.9 years with an SD of 2.87. Fifty-six residents (73.7%) were male and 45 (59.2%) were year 2 residents. Sixty-one (76.3%) had previous POCUS training. Fifty residents (82.0%) received training from the classroom. Twenty-seven residents (35.5%) rated their current level of knowledge as good for sterile transducer techniques, 28 (36.8%) rated fair for their knobology, and 27 (35.5%) rated very good for their transducer selection knowledge. Thirty-two (42.1%) rated very good about their ability to interpret IVC. 26 (34.2%) responded that they had good ability to interpret FAST/EFAST. Forty-nine (64.5%) residents claimed lack of an ultrasound machine followed by 33 (43.4%) lack of organized curriculum were the main barriers to POCUS utilization. Forty-two (55.3%) residents preferred to complete face-to-face teaching, while 33 (43.4%) preferred blended learning both face-to-face and online. POCUS is performed by the majority of EMCC residents. The most frequent scans performed by residents were FAST, IVC, and lung scans. Lack of ultrasound machine and organized curriculum was the main barrier to US utilization. Availability of equipment, face-to-face training, and having an organized curriculum are recommended by residents to improve their skills in the future.

Enhanced point of care ultrasound skills after additional instruction from simulated patients.

Point of Care Ultrasound (POCUS) training in Canadian undergraduate medical programs is steadily increasing. To date, the simulated patients (SPs) in our program have only provided feedback on comfort and professionalism. Involving the POCUS SPs as teachers (SP-teachers) of POCUS skills provides an additional opportunity for instruction. In this pilot study, we explored the impact of SP-teachers instructing medical trainees while they learned POCUS. Outcomes of interest included the level of proficiency achieved after the session and trainee satisfaction with the learning experience. Second year medical students were randomized into a conventional or SP-teacher learning experience. Both groups received the same video tutorial, instructor guidance, and basic SP feedback (comfort and professionalism). The SP-teaching group received additional instruction (landmarks, transducer technique, and troubleshooting) from the SP-teachers when session instructors were assisting others. Students evaluated the session and were subsequently assessed through direct observation. Students that received SP-teaching scored significantly higher in both image acquisition (p = 0.029, d = 1.26) and overall entrustment (p = 0.002, d =1.75). Both groups rated their sessions highly. Students that received SP-teaching were observed to better acquire images and achieved higher entrustment scores. In this pilot study, SP-teachers had a positive effect on acquisition of POCUS skills.

5. Reducing set screw loosening failures: an analysis of final tightening technique

<h3>BACKGROUND CONTEXT</h3> A 5% rate of S2AI screw failure consisting of rod slippage/set screw displacement has been reported. Fixation construct strength is largely dependent on the set screw's locking torque. Both the magnitude (how much torque is applied) and the rate (how fast the torque is applied) can impact set screw loosening failure. <h3>PURPOSE</h3> To evaluate the effect of set screw locking torque on the strength of the fixation construct. <h3>STUDY DESIGN/SETTING</h3> Benchtop biomechanical testing. <h3>METHODS</h3> Commercially available, Ti alloy 5.5mm polyaxial pedicle screws and set screws were used. To test the effect of the locking torque magnitude on construct strength, the set screws were tightened onto a Ti alloy rod at 85 and 105 in-lbs (N=8 each). A torque meter (TM) [Transducer Techniques, SWS-20] was attached to the driver to record both the locking and loosening torque. To test the effect of the rod alloy, the same implants were tested with 5.5 CoCr and Ti alloy rods (N=8 each). The set screws' locking and loosening torque were measured. Also, six torque limiting handles from five suppliers were attached to the same TM. To test the effect of torque application rate, an experienced user torqued the handle until the device's internal limit was reached. The resulting torque was measured. Each handle was subjected to 11 actuations at two rates fast (defined by taking less than one second to click over after resistance is felt) and slow (defined by taking 1-2 seconds to click over after resistance is felt). <h3>RESULTS</h3> Set screws tightened to 105.8(±.54)in-lbs retained 39.6% more torque than those tightened to 85.4(±.57)in-lbs(p <0.001), demonstrating that more torque applied results in more torque retained. Set screws tightened onto a Ti alloy rod retained 15.0% more torque than those tightened onto a CoCr rod (p < .003). When torque limiting handles are actuated at a slow rate, the resulting torque output produced is 22.6% higher than when actuated at a fast rate, demonstrating the magnitude of the torque applied is dependent on the rate at which the handle is rotated (p <0.05). <h3>CONCLUSIONS</h3> The choice of spinal rod alloy used may affect set screw security. More torque applied results in more torque retained; therefore, we recommend the final locking torque be applied in a slow and controlled manner to ensure the intended locking torque magnitude is applied. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.

Utilizing Electrochemical-Based Sensing Approaches for the Detection of SARS-CoV-2 in Clinical Samples: A Review.

The development of precise and efficient diagnostic tools enables early treatment and proper isolation of infected individuals, hence limiting the spread of coronavirus disease 2019 (COVID-19). The standard diagnostic tests used by healthcare workers to diagnose severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection have some limitations, including longer detection time, the need for qualified individuals, and the use of sophisticated bench-top equipment, which limit their use for rapid SARS-CoV-2 assessment. Advances in sensor technology have renewed the interest in electrochemical biosensors miniaturization, which provide improved diagnostic qualities such as rapid response, simplicity of operation, portability, and readiness for on-site screening of infection. This review gives a condensed overview of the current electrochemical sensing platform strategies for SARS-CoV-2 detection in clinical samples. The fundamentals of fabricating electrochemical biosensors, such as the chosen electrode materials, electrochemical transducing techniques, and sensitive biorecognition molecules, are thoroughly discussed in this paper. Furthermore, we summarised electrochemical biosensors detection strategies and their analytical performance on diverse clinical samples, including saliva, blood, and nasopharyngeal swab. Finally, we address the employment of miniaturized electrochemical biosensors integrated with microfluidic technology in viral electrochemical biosensors, emphasizing its potential for on-site diagnostics applications.

The Investigation of Detect Position of Partial Discharge in Cast-Resin Transformer Using High-Frequency Current Transformer Sensor and Acoustic Emission Sensor

The lifetime of a cast-resin transformer mainly depends on the condition of insulation material. Partial discharge (PD) is an important reason for insulation deterioration in cast-resin transformers. Identifying the position of PD is very necessary for damage assessment while the transformer is still operating, and the transformer is covered by housing. This paper proposes the investigation of a cast-resin transformer using an AE sensor and HFCT sensor to specify the precise source of PD. In this study, four AE sensors were used to find PD sources, and the high-frequency current transducer (HFCT) technique was used to identify the PD source and the criteria level. The experiment, in the first two parts, identified the possibility of PD, which includes the position of PD. The final part of the experiment verified the position of the PD source of a cast-resin transformer and confirmed the inspection results. AE and HFCT sensors can be used to detect the location of PD sources, confirming the position of the PD source by sensor detection. In addition, the evident partial discharge picture on the insulator surface of high voltage side. The process successfully and accurately identifies and locates the PD source.

Colonoscopic Ultrasound-Guided Fine-Needle Aspiration Using a Curvilinear Array Transducer: A Single-Center Retrospective Cohort Study.

Curvilinear array ultrasound transducers enable tissue sampling and have therapeutic capabilities. Nevertheless, colonic intubation and maneuvering with these transducers is technically challenging and is therefore typically limited to the rectosigmoid area. This retrospective cohort study aimed to evaluate the safety, feasibility, and diagnostic yield of colonoscopic ultrasound-guided fine-needle aspiration in deep colonic intubation. The impact of this innovation is to enable tissue sampling of colonic and extracolonic lesions guided by endoscopic ultrasound. Curvilinear array ultrasound is used in the evaluation of luminal and extraluminal colonic diseases. Thirteen patients underwent colonoscopic ultrasound with a curvilinear array ultrasound endoscope in a single center for subepithelial lesions, cancer staging, and extracolonic lesions from July 2015 to February 2021. Endosonography was performed using an Olympus EU-ME1 and GF-UCT 180 with a 5-12MHz curvilinear array transducer. The primary outcome was the percentage of patients who were successfully scanned with the endoscopic ultrasound. The secondary outcomes included the success rate of fine-needle aspiration, the diagnostic yield of the tissue samples, and the adverse events related to the procedure. A total of 13 female patients underwent colonoscopic ultrasound. All patients (100%, 13/13) were successfully scanned. Fine-needle aspiration was deemed necessary and successfully performed in 100% (5/5) of the patients. Tissue samples collected by fine-needle aspiration resulted in a diagnostic yield of 60%, and no adverse events resulted from this intervention. This study demonstrates the feasibility of performing colonoscopic ultrasound with a curvilinear array transducer. Fine-needle aspiration for subepithelial, colonic, and extracolonic lesions is feasible and safe in this setting with no adverse events reported in our study. Future research should be directed toward validating colonoscopic ultrasound with a curvilinear array transducer technique in prospective randomized trials. Studies evaluating the feasibility and safety of endoscopic ultrasound-guided interventions in the colon, such as abscess drainage and enteral anastomosis, should be considered.

Emerging biosensing and transducing techniques for potential applications in point-of-care diagnostics.

With the deepening of our understanding in life science, molecular biology, nanotechnology, optics, electrochemistry and other areas, an increasing number of biosensor design strategies have emerged in recent years, capable of providing potential practical applications for point-of-care (POC) diagnosis in various human diseases. Compared to conventional biosensors, the latest POC biosensor research aims at improving sensor precision, cost-effectiveness and time-consumption, as well as the development of versatile detection strategies to achieve multiplexed analyte detection in a single device and enable rapid diagnosis and high-throughput screening. In this review, various intriguing strategies in the recognition and transduction of POC (from 2018 to 2021) are described in light of recent advances in CRISPR technology, electrochemical biosensing, and optical- or spectra-based biosensing. From the perspective of promoting emerging bioanalytical tools into practical POC detecting and diagnostic applications, we have summarized key advances made in this field in recent years and presented our own perspectives on future POC development and challenges.

Design and Development of Morphological Analyzer for Tigrigna Nouns Using Finite State Transducer Techniques

Design and Development of Morphological Analyzer for Tigrigna Nouns Using Finite State Transducer Techniques

Analytical Modeling of an Electrochemical Sensor Used in Electrolysis Mode and Exposed to a Binary Mixture of Gases

Today, air pollution has become a major society issue. With the increased development of motorized vehicles, polluting and even toxic gases are being released in increasing quantities into the atmosphere with all known consequences [1] [2]. With the apparition of the concerns about impacts of human activity into the global warming, European legislations have started to impose more and more drastic emission limits through the euro norms (euro 6B currently). The norms concern both particles and polluting gases emitted from motorized vehicles. In a close future, industries, and particularly those having combustion furnaces will also be impacted by the norm. Therefore, controlling emitted gases and particles has become a major issue for car manufacturers and the development of new sensors responding to the requirements of the harsh environments present in exhausts has emerged. In response to those requirements, electrochemical sensors based on solid-state ceramic electrolyte are well-adapted [3] [4]. However, like for gas sensors based on other transducing techniques, a lack of selectivity compels the sensors’ developers to find different methods to extract the analyte’s nature and concentration information. According to the sensing principle, the gas analytes will be discriminated according to different of their properties. For example, in the case of microbalances, the sensor’s response will rely only to the mass deposited. In this case, it seems difficult to discriminate the gas nature since the mass is not specific to one specie in particular. The output sensor’s signal will give concentration information but no information linked to analyte’s nature. Besides, in the case of electrochemical sensors (like for MOX sensors), the sensor’s response will both give information on the analyte’s concentration and on its redox behavior. Different models describing electrochemical sensors already exist in the literature for null current potentiometry based measurement (thermodynamic equilibrium). In this case, models used to describe the operation of the sensor are often based on the mixed potential theory [5]. However, only few of them describe the sensor’s kinetics behavior when used in electrolysis mode (imposed current potentiometry). In this work, two analytical models describing the response of an electrochemical sensor used in his electrolysis mode are proposed and compared. Those model results from the association of the Butler-Volmer equations and an equivalent electrical circuit describing the parallel reactions that can occur at the triple phase interfaces of the electrodes. The first model considers that both oxidizing gases and reducing gases react at the gold cathode whereas the second one considers that only oxidizing gases react at the gold cathode, the reducing gases just adsorbing on the cathode which induce slowing down of the reaction kinetics of other O2 oxidizing gas.Besides, to test those models, different experimental curves, obtained thanks to our gas test bench and our “homemade” screen-printed electrochemical sensors, were used. Apart from O2, which is always present in the dilution air or in the “base gas”, the sensors were exposed to four different polluting analytes: NO2, NO, NH3, CO. To perform curve fitting, MATLAB algorithms were developed. 3 methods were chosen perform curve fitting and parameters extraction: the Least Squares method, the Newton-Gauss method and the Levenberg-Marquardt method. For each one, an iterative algorithm was developed to extract the vector values containing the fitting parameters. First results indicate good fitting performance for both oxidizing and reducing gases in the case of model 2 whereas for the first model, relevant fitting results could only be obtained for oxidizing gases.

Feedthrough parasitic nonlinear resonance in micromechanical oscillators

Mechanical oscillators incorporating miniaturized structures to transduce mesoscopic motion as readable electrical signals are often limited by the feedthrough effect (FE) because oscillation features are corrupted. The knowledge of FE parasitic resonance hitherto is only demonstrated in the linear regime. Herein, we reveal the nature of phenomenological FE parasitic nonlinear resonance. An inverse distortion in the spectra resulting from the superposition of Duffing nonlinearity and the FE is observed and modeled with physical insight into the governing parameters. We find that the manipulation of electromechanical coupling of the oscillator can fully de-embed the FE, while the device oscillates at the nonlinear bifurcation point under phase control. The generic nature of our model indicates that similar dynamic behaviors will occur for the nonlinear resonant systems containing the FE, regardless of transducing techniques. The strategy of on-chip FE control in our capacitive platform is scalable and can be suitably transformed for application in oscillators employing alternative transducers.

A Review of Acoustic Impedance Matching Techniques for Piezoelectric Sensors and Transducers.

The coupling of waves between the piezoelectric generators, detectors, and propagating media is challenging due to mismatch in the acoustic properties. The mismatch leads to the reverberation of waves within the transducer, heating, low signal-to-noise ratio, and signal distortion. Acoustic impedance matching increases the coupling largely. This article presents standard methods to match the acoustic impedance of the piezoelectric sensors, actuators, and transducers with the surrounding wave propagation media. Acoustic matching methods utilizing active and passive materials have been discussed. Special materials such as nanocomposites, metamaterials, and metasurfaces as emerging materials have been presented. Emphasis is placed throughout the article to differentiate the difference between electric and acoustic impedance matching and the relation between the two. Comparison of various techniques is made with the discussion on capabilities, advantages, and disadvantages. Acoustic impedance matching for specific and uncommon applications has also been covered.

Measurement of Gas–Solid Dispersion Characteristics in a Slurry Flotation Column Using ERT Technique

This work mainly aims on the investigation of phase hold-up characteristics in a column flotation at different feed solid concentrations performing for an extensive range of working conditions. Phase hold-ups are measured using the electrical resistance tomography (ERT) coupled with pressure transducers technique. Experiments are conducted for two different nature mineral particles: hydrophilic (silica) and semi-hydrophobic (oxidized coal). The impact of gas superficial velocity, feed superficial velocity and pulp slurry height for a fixed sparger and frother addition on the gas and solid dispersion are studied. Gas hold-up increases with the gas flowrate and slurry feed rate, decreases with solid concentration. Further, bubble dynamics is estimated using coupled ERT with dynamic gas disengagement (DGD) approach. It is found that the solid’s presence affect the bubble swarm velocity thereby causing local gas holdup to drop. Possible mechanisms due to solid particles on gas dispersion are discussed and verified in the light of current experimental results.