Ultrasonic Velocity Profiler for the Measurement of a Bubbly Flow Velocity Vector in Small Channels

The multi-dimensional velocity distribution of coolant in bubbly flow within the fuel rod bundles of the reactor core in boiling water reactors (BWRs) is elucidated by experimental investigation in this study. Since a measurement technique is required for such an investigation, this paper proposes the development of an ultrasonic velocity profiler (UVP). The combination of special ultrasonic transducers and modified signal processing on the UVP is proposed to obtain a multi-dimensional velocity vector of the bubbles and liquid in bubbly flow. The ability of the proposed technique is demonstrated by performing an experiment in swirling bubbly flow and its applicability confirmed by comparing the results with another technique. The sound pressure distribution in the narrow channel of the rod bundle is then measured prior to the verification of the ultrasonic wave emitted through a small channel. The echo signal reflected from reflectors dispersed in the liquid, bubble, and tracer particles in the small channel of the rod bundle indicates that the proposed UVP can be applied in this application with a low level of multi-reflection. Finally, the UVP system is demonstrated to measure the velocity vector of bubbly flow in the narrow flow channel on the rod bundle, and the velocity vector of the bubble and liquid obtained simultaneously

An Experimental Study of Different Signal Processing Methods on Ultrasonic Velocity Profiles in a Single Phase Flow

Ultrasonic velocity profile (UVP) measurement methods have been continuously developed in the field of engineering. A UVP can visualize a fluid flow along a benchmark line. This provides a significant advantage over other conventional methods such as differential pressure, turbine, and vortex. This paper presents an experimental study of using different signal processing methods including autocorrelation (AC), fast Fourier transform (FFT), maximum likelihood estimation (MLE), multiple signal classification (MUSIC), and Estimation of signal parameter via rotational invariance technique (ESPRIT) under diverse situations as the number of pulse repetitions (Nprf), frequency of repetitions (fprf), velocity profiles, computation – time requirements and flowrates. Experimental results express that there is an optimal number and frequency of pulse repetitions for each signal processing method that depended on fprf, Nprf, and flowrate. Moreover, computation-time and statistical tests were verified from experimental results. From the comparisons, MLE was experimentally the best algorithm even though the trade-off of moderate computation-time requirements was realized. However, considering the optimization of both accuracy and computation-time consumption, MLE was determined as the preferred signal processing method based on UVP for estimating flowrate in existing water reactors. &nbsp

Ultrasonic Velocity Profiler for the Measurement of a Bubbly Flow Velocity Vector in Small Channels

The multi-dimensional velocity distribution of coolant in bubbly flow within the fuel rod bundles of the reactor core in boiling water reactors (BWRs) is elucidated by experimental investigation in this study. Since a measurement technique is required for such an investigation, this paper proposes the development of an ultrasonic velocity profiler (UVP). The combination of special ultrasonic transducers and modified signal processing on the UVP is proposed to obtain a multi-dimensional velocity vector of the bubbles and liquid in bubbly flow. The ability of the proposed technique is demonstrated by performing an experiment in swirling bubbly flow and its applicability confirmed by comparing the results with another technique. The sound pressure distribution in the narrow channel of the rod bundle is then measured prior to the verification of the ultrasonic wave emitted through a small channel. The echo signal reflected from reflectors dispersed in the liquid, bubble, and tracer particles in the small channel of the rod bundle indicates that the proposed UVP can be applied in this application with a low level of multi-reflection. Finally, the UVP system is demonstrated to measure the velocity vector of bubbly flow in the narrow flow channel on the rod bundle, and the velocity vector of the bubble and liquid obtained simultaneously

Ocular Microbiota of Severe Meibomian Gland Dysfunction (Chronic Dry Eyes) after Intense Pulsed Light (IPL)

Ocular IPL therapy has recently been widely used for MGD, especially for patients not showing improvement with traditional therapies (warm compresses and lid scrubs) to clean debris and reduce bacterial overgrowth. Insights on the ocular microbiome and quantitative microbiome in MGD after a course of IPL could provide useful data on bacterial community monitoring and associated mechanisms linked with IPL. Ocular swabs were obtained from a severe MGD patient and age-sex matched healthy for metagenomics, followed by 16S rRNA gene sequencing and qPCR. Of 10 samples, including left and right eyes (el, er) of severe MGD females before (Db) and after 2-4 IPLs (Da2, Da3, and Da4) and the matched non-MGD females (H), both of ~40 years Using 16S rRNA gene sequencing as microbiota and combined 16S rRNA gene qPCR as quantitative microbiota revealed significant disperse in the microbiome structures of Db compared with Da and H (HOMOVA, p<0.001). Bacterial Propionibacterium acnes and unclassified taxa in the family Propionibacteriaceae and order Actinomycetales represented the core Db microbiota and were reduced after 2-4 IPLs in Da, making the Da microbiome and clinical (mucocutaneous junction, corneal, and conjunctival fluorescein score) closer to H (NMDS with Pearson’s correlation, p<0.05). The recovery of the Da microbiome also allowed Da metabolic potentials to be closer to H. Our findings first demonstrated the ocular microbiome dysbiosis in severe MGD, dispersed from Da and H, in Thai subjects, correlated with bacterial quantity and clinical MGD, including the mucocutaneous junction process. The results additionally provided taxa representing Db vs. Da and H and preliminarily underlie the idea that IPL could improve dysbiosis in the MGD microbiome. Doi: 10.28991/ESJ-2023-07-05-015 Full Text: PD

Potential impact of ocular intense pulsed light on eyelash microbiome in severe meibomian gland dysfunction: report of 2 cases

Meibomian gland dysfunction (MGD) is a prevalent worldwide eye disorder that causes eye irritation, inflammation, chronic dryness, and blurred vision. Traditional therapies offer temporary improvement, but their efficacy varies in severe MGD cases. Ocular intense pulsed light (IPL) has emerged as a novel therapy, providing long-term symptom relief and shorter treatment durations compared to traditional approaches. However, the impact of IPL on the bacterial community within the eyes remains limited. To address this, we conducted a preliminary study using metagenomics and next-generation sequencing. We compared the bacterial eyelash communities of Thai females with severe MGD before and after 2-4 IPL treatments, and against a group of healthy females. Our findings revealed higher bacterial diversity in healthy individuals compared to severe MGD cases. IPL treatments increased diversity in the MGD group, making their core bacterial community more similar to that of healthy subjects. Notably, the presence of Koribacteraceae in severe MGD and Bifidobacterium in healthy individuals and post-IPL-treated MGD exemplified this shift. Clustering analysis showed a closer relationship between post-IPL-treated MGH and healthy subjects, while the pre-IPL treatment group formed a separate branch. These results suggest that IPL treatment can reshape the eyelash microbiome in MGD cases, but further research is needed to understand the implications and the microbiome’s role in MGD pathogenesis and treatment response

Molecular Typing of Vibrio cholerae O1 Isolates from Thailand by Pulsed-field Gel Electrophoresis

The aim of the present study was to genotypically characterize Vibrio cholerae strains isolated from cholera patients in various provinces of Thailand. Two hundred and forty V. cholerae O1 strains, isolated from patients with cholera during two outbreaks, i.e. March 1999–April 2000 and December 2001–February 2002, in Thailand, were genotypically characterized by NotI digestion and pulsed-field gel electrophoresis (PFGE). In total, 17 PFGE banding patterns were found and grouped into four Dice-coefficient clusters (PF-I to PF-IV). The patterns of V. cholerae O1, El Tor reference strains from Australia, Peru, Romania, and the United States were different from the patterns of reference isolates from Asian countries, such as Bangladesh, India, and Thailand, indicating a close genetic relationship or clonal origin of the isolates in the same geographical region. The Asian reference strains, regardless of their biotypes and serogroups (classical O1, El Tor O1, O139, or O151), showed a genetic resemblance, but had different patterns from the strains collected during the two outbreaks in Thailand. Of 200 Ogawa strains collected during the first outbreak in Thailand, two patterns (clones)—PF-I and PF-II—predominated, while other isolates caused sporadic cases and were grouped together as pattern PF-III. PF-II also predominated during the second outbreak, but none of the 40 isolates (39 Inaba and 1 Ogawa) of the second outbreak had the pattern PF-I; a minority showed a new pattern—PF-IV, and others caused single cases, but were not groupable. In summary, this study documented the sustained appearance of the pathogenic V. cholerae O1 clone PF-II, the disappearance of clones PF-I and PF-III, and the emergence of new pathogenic clones during the two outbreaks of cholera. Data of the study on molecular characteristics of indigenous V. cholerae clinical isolates have public-health implications, not only for epidemic tracing of existing strains but also for the recognition of strains with new genotypes that may emerge in the future

Molecular Typing of Vibrio cholerae O1 Isolates from Thailand by Pulsed-field Gel Electrophoresis

The aim of the present study was to genotypically characterize Vibrio cholerae strains isolated from cholera patients in various provinces of Thailand. Two hundred and forty V. cholerae O1 strains, isolated from patients with cholera during two outbreaks, i.e. March 1999-April 2000 and December 2001-February 2002, in Thailand, were genotypically characterized by NotI digestion and pulsed-field gel electrophoresis (PFGE). In total, 17 PFGE banding patterns were found and grouped into four Dice-coefficient clusters (PF-I to PF-IV). The patterns of V. cholerae O1, El Tor reference strains from Australia, Peru, Romania, and the United States were different from the patterns of reference isolates from Asian countries, such as Bangladesh, India, and Thailand, indicating a close genetic relationship or clonal origin of the isolates in the same geographical region. The Asian reference strains, regardless of their biotypes and serogroups (classical O1, El Tor O1, O139, or O151), showed a genetic resemblance, but had different patterns from the strains collected during the two outbreaks in Thailand. Of 200 Ogawa strains collected during the first outbreak in Thailand, two patterns (clones)-PF-I and PF-II-predominated, while other isolates caused sporadic cases and were grouped together as pattern PF-III. PF-II also predominated during the second outbreak, but none of the 40 isolates (39 Inaba and 1 Ogawa) of the second outbreak had the pattern PF-I; a minority showed a new pattern-PF-IV, and others caused single cases, but were not groupable. In summary, this study documented the sustained appearance of the pathogenic V. cholerae O1 clone PF-II, the disappearance of clones PF-I and PF-III, and the emergence of new pathogenic clones during the two outbreaks of cholera. Data of the study on molecular characteristics of indigenous V. cholerae clinical isolates have public-health implications, not only for epidemic tracing of existing strains but also for the recognition of strains with new genotypes that may emerge in the future

The CydDC family of transporters

The CydDC family of ABC transporters export the low molecular weight thiols glutathione and cysteine to the periplasm of a variety of bacterial species. The CydDC complex has previously been shown to be important for disulfide folding, motility, respiration, and tolerance to nitric oxide and antibiotics. In addition, CydDC is thus far unique amongst ABC transporters in that it binds a haem cofactor that appears to modulate ATPase activity. CydDC has a diverse impact upon bacterial metabolism, growth, and virulence, and is of interest to those working on membrane transport mechanisms, redox biology, aerobic respiration, and stress sensing/tolerance during infection

A Novel Ultrasonic Method for Measuring the Position and Velocity of Moving Objects in 3D Space

This study proposes a method for concurrently determining the position and velocity of a moving object in three-dimensional (3D) space using echolocation. A spherical object, i.e., a flying ball, is used to demonstrate the ability of the proposed method. The position of the object is calculated using a time-of-flight (TOF) technique based on a cross-correlation function, which requires less computational time when using one-bit signal technology. The velocity of the object is subsequently computed from the length of chirp signals and the velocity vector measurements between the position of the object and the position of acoustical receivers. The coordinate of the object location is identified by the distance from the sound source to the object, the elevation angle, and the azimuth angle. The validity and repeatability of the experimental results are evaluated by statistical methods, showing ±1% of accuracy. It is concluded that the proposed method can identify the position and velocity of a rigid body in 3D space