Amplitude Measurements Research Articles

Spindle Bearing Preload Control Using NI MyRIO

The article presents an application for controlling the preload of bearings in a model spindle system. The bearing preload will be implemented using piezoelectric elements, which allow for changing the preload of bearings during spindle operation, which results in a change in the stiffness of the entire system. Such a change in stiffness allows for effective reduction of the vibration amplitudes of the spindle tip. The use of the MyRIO 1900 device from National Instruments, which was programmed using LabVIEW 2021 SP1 (32 bit), is described in detail. The effectiveness of the control algorithm was confirmed on the basis of actual measurements of the vibration amplitude of the front spindle tip on which three different substitute masses (model grinding wheels) were placed. The values for the system without and with the operating control system were compared. The results were recorded five times for each state of the device and each substitute mass. The value of the maximum amplitude was taken into account after averaging it from all five tests without control and with control. The effectiveness of the control algorithm was the greater the heavier the substitute mass, which allowed for reducing the vibration amplitude by up to 20%.

Granulocyte colony-stimulating factor promotes regeneration of severed facial nerve in rats

Background and aimThe administration of growth and neurotrophic factors has been attempted experimentally as a new therapeutic strategy for severe facial paralysis. Granulocyte colony-stimulating factor (G-CSF) has an effect on the treatment of central nervous system injuries, such as cerebral infarction and spinal cord injury. This study aimed at examining the effects of G-CSF on facial nerve regeneration in rats.MethodsThe left facial nerve of rats was either partially resected (resection group) or severed and sutured (suture group) at the main trunk outside the temporal bone. In each surgical group, saline or G-CSF was administered via the gelatin hydrogel drug delivery system. The suture group was further divided into two subgroups for the late administration of G-CSF (2 weeks after surgical treatment) or immediate administration of G-CSF after surgical treatment. Recovery of the facial nerve was assessed by the evaluation of facial movements (after 12 weeks), complex muscle action potential amplitude measurements (after 2, 4, 8, and 12 weeks), electroneurography values (after 12 weeks), and histological evaluation (comparison of myelinated axon diameters among the groups).ResultsRecovery of the function and morphology of damaged nerves was faster in the suture groups than in the resection group. In the suture groups, recovery was faster for G-CSF-treated rats than for saline-treated rats. Furthermore, recovery was faster in the group that received G-CSF immediately after surgical treatment than in the group that received G-CSF 2 weeks later. However, the group that received G-CSF 2 weeks later also showed faster recovery than did the control group.ConclusionG-CSF effectively promoted nerve regeneration during facial nerve paralysis. Thus, G-CSF may be a potential treatment strategy for injured facial nerves as it has been safely administered in clinical treatments for hematological diseases.

PETAT — an ASIC for simple and efficient readout of large PET scanners

Modern PET scanners based on scintillating crystals use solid state photo detectors for light readout. The small area of these devices is beneficial for spatial resolution, but also leads to a large number of electronic channels to be read out, mostly by application specific integrated circuits (ASICs) containing amplification, noise reduction, hit finding, time stamping and amplitude measurement. Although each ASIC provides up to ≈ 64 channels, a large number of chips is required with the need for auxiliary electronic components like voltage regulators or FPGAs for control and data readout. The FPGAs in turn often require multiple supply voltages and configuration infrastructure, so that PCBs get complicated, cumbersome and power-hungry, in addition to the significant power requirement of the front-end ASICs. We address this issue in the latest generation of our PETA readout ASIC for SiPMs by a simplified control scheme and, in particular, by a hierarchical serial data readout which does not require any additional FPGA. In addition, it provides a time-sorted stream of hit data, allowing early on-detector data reduction and hit pre-processing like the removal of hits with no coincident partner. The simplicity of this readout facilitates a supply scheme where power/ground of multiple ASICs are connected in series instead of the standard parallel connection. This `serial-powering' approach can reduce supply current (while increasing overall supply voltage) so that voltage drop issues in the supply are alleviated.

Wave Atmospheric Disturbances from the Solar Terminator in the Morning and Evening Hours Based on Measurements of Amplitudes of VLF Radio Signals

Wave Atmospheric Disturbances from the Solar Terminator in the Morning and Evening Hours Based on Measurements of Amplitudes of VLF Radio Signals

The intersubject reliability of cortical auditory evoked potential (CAEP) in pediatric cochlear implant recipients: comparisons between acoustic and electrical stimulations.

To compare the intersubject reliability of cortical auditory evoked potential (CAEP) elicited by acoustic and electrical stimulations in pediatric cochlear implant (CI) recipients. Twenty-two MED-EL CI recipients (aged 13-93 months) participated in this study. The acoustic CAEP (aCAEP) waveforms were elicited using four speech stimuli (/ba/, /m/, /g/, and /t/) presented at 65 dB SPL in a free-field condition. The electrical CAEP (eCAEP) responses were obtained by presenting electrical pulses through apical, medial, and basal electrodes. The aCAEP and eCAEP data (n = 28 ears) were analyzed using coefficient of variation (CV) and other appropriate statistics. P1, N1, and P2 peaks were observed in most of the children (92.9% response rate). The CV values were smaller for the latency metric (13.6-34.2%) relative to the amplitude metric (51.3-92.4%), and the differences were statistically significant (p < 0.001). The aCAEP yielded smaller mean CV values than the eCAEP (for both latency and amplitude measures), and the mean CV value for the aCAEP (15.6%) was found to be statistically different from that of the eCAEP (31.0%) for the P1 latency (p = 0.001). This study is the first to report the intersubject reliability of aCAEP and eCAEP in pediatric CI recipients. Overall, CAEP latencies were found to be more reliable than CAEP amplitudes, and the aCAEP testing demonstrated higher intersubject reliability compared to the eCAEP assessment. The present study's findings can be beneficial for researchers and clinicians in documenting CAEP in children who use CI.

Non-collinear wave mixing to determine physical ageing in PVC pipelines

The ultrasonic signal amplitudes obtained from non-collinear wave mixing has previously shown significant changes for physically aged Poly-Vinyl Chloride (PVC) pipes, demonstrating the method's effectiveness in assessing the ageing condition of PVC. However, the exact relationship between the measured amplitudes and the extent of physical ageing in PVC has yet to be established. Additionally, it has not yet been validated against established methods or applied to determine the service lifetime of PVC pipes. This study outlines a three-step process to validate the effectiveness of the non-collinear wave mixing technique for assessing the physical ageing of PVC pipelines. Firstly, the non-collinear wave mixing results are compared with the established laboratory method of differential scanning calorimetry, to validate the scattered wave amplitude measurements. Secondly, employing the Arrhenius relation, service lifetime estimates derived from non-collinear wave mixing results align within the expected magnitudes, emphasizing the technique's potential for in-situ pipeline inspections. Finally, a material model is utilized to estimate the Third Order Elastic Coefficient (TOEC) m based on the measured amplitudes, demonstrating a linear correlation with annealing time. A 50% change in TOEC m signifies a brittle state, indicating a high risk of failure. A combination of experimental and analytical analyses highlighted TOEC m variations as the primary factor influencing non-collinear wave mixing amplitude changes during physical ageing. This comprehensive approach also highlights the importance of incorporating diverse factors to precisely forecast and oversee the performance of PVC pipes in real-world environments.

Abstract 4136762: Association Between Circadian Rest/Activity Rhythms and Incident Dementia in Older Adults: The Atherosclerosis Risk in Communities (ARIC) Study

Introduction: Alterations in circadian rest/activity rhythms (RARs) are common among older adults. RARs can be derived from accelerometry data and are routinely used as proxy measures. Evidence suggests that altered (e.g., fragmented, delayed) RARs may be risk factors for dementia. However, results have been mixed. Using data from the ARIC Study, a community-based cohort, we assessed the association between RARs and incident dementia. Methods: ARIC participants without dementia who wore the Zio XT ECG Patch in 2016-17 for &gt; 3 days were included. RARs were obtained from an accelerometer within the Zio XT ECG Patch and measures of interdaily stability (IS; consistency), intradaily variability (IV; fragmentation), and relative amplitude (RA; strength) were derived. Dementia cases were identified through 2020 using in-person and phone-based cognitive assessments, hospitalization discharge codes, or death certificates. Cox proportional hazards models were used. Results: Of the 2,183 participants (mean [SD] age 79 [4.5] years, 58% female, 24% identified as Black), 176 (8%) developed dementia. Median follow-up time was 3 years and mean Zio XT ECG Patch wear time was 12 days. After multivariable adjustment, lower RA and higher IV were associated with incident dementia (HRs [95% CIs] per 1-SD increment: 0.65 [0.56-0.76], 1.19 [1.02-1.38]). No significant association between IS and dementia was noted; however, there was an interaction by race (p=0.03). Stratified results were not significant, but effect estimates were in opposite directions: (HRs [95% CIs] per 1-SD increment in IS: 0.78 [0.59-1.02] in Black participants and 1.17 [0.96-1.41] in white participants, respectively). No interactions by sex or APOEε4 were noted (p&gt;0.10). Conclusion: In this community-based cohort of older adults, weaker circadian rhythm strength and fragmentation were associated with dementia risk. The association between IS and dementia may differ by race; however, this needs to be further examined in future research. Overall, measures of circadian RARs may be risk factors for dementia. Additional research is warranted to determine whether they can be novel targets for dementia prevention.

Abstract Su203: Development of Bioimpedance for the Measurement of Ventilation During Cardiopulmonary Resuscitation

Introduction: Previous studies have shown that ventilation during cardiopulmonary resuscitation (CPR) produces better patient outcomes. However, research regarding ventilation during the early stages of basic life support CPR is limited. Prior studies showed that thoracic bioimpedance, recorded by the LifePak 12 defibrillator device, can be used to count ventilations with a tidal volume at least 250 mL during CPR. However, the relationship between thoracic bioimpedance and tidal volume has yet to be studied for the Phillips MRx device, excluding a large data set from ventilation studies. Hypothesis: Bioimpedance, measured by the Phillips MRx device has a linear relationship with tidal volume. Aims: To determine the relationship between bioimpedance measured by the Phillips MRx device and tidal volume in males and females. Methods: We conducted the study in a respiratory laboratory at a University Hospital. We asked 27 volunteers to breathe fixed volumes (250 mL, 300 mL, 400 mL, 600 mL, and 800 mL) delivered by a mechanical ventilator while recording bioimpedance simultaneously with the Philips MRx monitor-defibrillator through electrode pads placed on the chest. Six measurements of bioimpedance waveform amplitudes (Ohms) were taken at each tidal volume. Results: Of 27 volunteers, 11 were female and 16 were male. In the female sample set, a linear equation of y=0.003x + 0.837 with an R^2 value of 0.9995 was calculated. In the male sample set, a linear equation of Y=0.0016x +0.1039 with a R^2 value of 0.995 was calculated. Females had a higher median bioimpedance amplitude than men at each tidal volume, and a steeper linear regression slope. At the minimum threshold tidal volume used for counting ventilations (250 mL), the median bioimpedance amplitude was 0.5 (0.4, 0.6) ohm for males and the median bioimpedance amplitude was 0.8 (0.6, 1) ohm for females. Conclusion: As measured and recorded with the Philips MRx monitor-defibrillator, there is a linear relationship between tidal volume and thoracic bioimpedance. The linear models created in this study can be used in future studies to count ventilations during CPR using the Philips MRx device.

Effectiveness of auditory measures in the diagnosis of cochlear synaptopathy and noise-induced hidden hearing loss: a case–control study

BackgroundCochlear synaptopathy is a disorder where auditory perceptual impairments, such as speech perception in noise and tinnitus, may not be accurately reflected by audiometric thresholds, even if the audiogram appears normal. It is proposed that the connections between hair cells and the auditory nerve are more susceptible to sound and aging damage than the cochlea’s hair cells. Cochlear synaptopathy can be present in ears with normal audiograms and undamaged hair cells, leading to hidden hearing loss. This study aims to construct electrophysiological and behavioral auditory parameters associated with persons exposed to loudness and having normal audiograms and auditory complaints to identify hidden hearing loss.ResultsA case–control study was done with forty participants with a documented history of exposure to loud sounds and various auditory complaints, compared to a control group of forty persons who had all been confirmed to have normal audiograms. The chosen behavioral core tests comprised the speech intelligibility in noise test (SPIN), gaps detection in noise (GIN test), and pitch pattern sequence test (PPS). The electrophysiological measures utilized in the study were the auditory brainstem response test (ABR) and electrocochleography (ECochG). The SPIN, PPS, and GIN test results demonstrated statistically significant disparities between the control and case groups. The amplitude ratio of wave I to wave V in ABR and the ratio of EcochG AP to SP demonstrated a statistically significant variance between the two groups. The SPIN test exhibited the highest AUC, signifying its superior diagnostic capability in identifying hidden hearing loss.ConclusionThe present study has shown that the SPIN, as a behavioral test, and the EcochG AP amplitude measure, as an electrophysiological test, provide the greatest auditory diagnostic capability for identifying cochlear synaptopathy. Wave I amplitude in the auditory brainstem response (ABR) and the SP/AP ratio in electrocochleography (EcochG) are promising non-behavioral measures of cochlear synaptopathy or hidden hearing loss.

Diagnostic significance of the method of computerized joint vibration analysis in studying the functional state of temporomandibular joints

polyetiology, progressive course and high frequency of relapses is one of the urgent problems of modern dentistry. Different conceptual approaches to the analysis of etiological and pathogenetic aspects of the development of dysfunctional TMJ disorders predetermine the increased interest in the search for highly informative diagnostic methods, especially at the stage of preclinical manifestations.Goal. Evaluation of possibilities of computerized joint vibration analysis method in diagnostics of TMJ functional state.Materials and methods. The study involved 42 people of both sexes with physiologic types of bite, preserved tooth rows, no signs of functional disorders in TMJ and masticatory muscles. The patients underwent clinical dental examination, «Hamburg test», selective grinding of teeth, and measurement of mouth opening amplitude. Joint vibration analysis was performed on the hardware-software complex «BioPAK» with registration of TMJ noise oscillations according to the following indices: «Total Integral», «High Integral», «Low Integral», «Ratio». A flow chart (Ishigaki S. et al., 1993) was used to interpret the numerical values. The functional state of TMJ was de-termined according to the flowchart using numerical parameters in accordance with the classification of TMJ disorders (Wilkes С.Н., 1989).Results. In patients with physiologic occlusion, according to joint vibration analysis, Me «Total Integral» of the right TMJ was 11.7 PaHz, left TMJ – 12.6 PaHz, [Q-25; Q-75] – [9.3; 15.1] PaHz and [10.5; 18.3] PaHz respectively, Me «High Integral» of the right TMJ – 1.3 PaHz, left TMJ – 1.4 PaHz, [Q-25; Q-75] – [1.0; 1.8] PaHz and [1.2; 2.1] PaHz respectively, with no statistically significant (p≤0.05) differences in the studied parameters between the right and left TMJ.Conclusions. The diagnosis of «structurally intact» TMJ, corresponding to stage I of the American classification of TMJ disorders (Wilkes S.N., 1989) in people with physiologic types of bite, is confirmed by the numerical values [Q-25; Q-75] of «Total Integral», «High Integral» (block diagram of S. Ishigaki et al., 1993), the degree of maximum mouth opening [43; 50] mm in the absence of pronounced signs of facial asymmetry.

The impact of EEG electrode density on the mapping of cortical activity networks in infants

ObjectiveElectroencephalography (EEG) is widely used for assessing infant's brain activity, and multi-channel recordings support studies on functional cortical networks. Here, we aimed to assess how the number of recording electrodes affects the quality and level of details accessible in studying infant's cortical networks. MethodsDense array EEG recordings with 124 channels from N=20 infants were used as the reference, and lower electrode numbers were subsampled to simulate recording setups with 63, 31, and 19 electrodes, respectively. Cortical activity networks were computed for each recording setup and different frequencies using amplitude and phase correlation measures. The effects of the recording setup were systematically assessed on global, nodal, and edge levels. ResultsCompared to the reference 124-channel recording setup, lowering electrode density affected network measures in a modality- and frequency-specific manner. The global network features were essentially comparable with 63 or 31 channels. However, the analytic reliability of the local network measures, both at nodal and edge levels, was proportional to the electrode density. The low-frequency amplitude correlations were most robust to the number of recording electrodes, whereas higher frequency phase correlation networks were most sensitive to the density of recording electrodes. ConclusionsOur findings suggest strong and predictable effects of recording setup on the network analyses. Higher electrode number supports studies on networks with phase correlations, higher frequency, and finer spatial details. SignificanceThe relationship between the recording setup and reliability of network analyses is essential for the prospective design of research data collection, as well as for guiding analytic strategies when using already collected EEG data from infants.

Wave atmospheric disturbances from the solar terminator in the morning and evening hours based on measurements of amplitudes of VLF radio signals

Wave atmospheric disturbances from the solar terminator in the morning and evening hours based on measurements of amplitudes of VLF radio signals

Correlation models for next-generation amplitude and cumulative intensity measures using artificial neural networks

Various next-generation intensity measures (IMs) have emerged in recent years. For instance, filtered incremental velocity, FIV3, was shown to be efficient in predicting the collapse of structures, or average spectral acceleration, Saavg, shown to be well-correlated with a wide range of response, from initiation of structural damage yielding to structural collapse. Different ground motion models (GMMs) are available to predict the probabilistic distribution of these IMs, given a set of seismological parameters. Nonetheless, a few key correlation models are still missing in the literature, which are elemental for a more holistic approach to ground motion record selection. These models are vital when performing seismic hazard analysis and ground motion record selection using state-of-the-art approaches like the conditional spectrum or generalized conditional intensity measure (GCIM) methods. This study uses a single machine-learning-based generalized ground motion model (GGMM) to estimate all the IMs. The model is based on the Next-Generation Attenuation (NGA)-West2 database and was utilized to quantify the correlations between the residuals. Correlations were calculated for intra- and inter-event residuals, but only those for total residuals are presented here, given their utility. Since the calculation of residuals comes from the same GMM and the same database of ground motions, this produces more consistent correlation coefficients between all IMs. To facilitate the usage of these correlation coefficients, predictive models of the empirical data were developed using machine-learning-based techniques, namely artificial neural networks (ANNs). It was found that FIV3 is strongly correlated with Sa(~1 s) and itself across all periods and has a weak negative correlation with duration at short periods and near-zero correlation for longer periods. Also, a stronger negative correlation between Sa and significant duration was found, compared with other prominent existing models. Direct correlation models between Sa and Saavg are also proposed.

Change in grounding line location on the Antarctic Peninsula measured using a tidal motion offset correlation method

Abstract. The grounding line position of glaciers and ice shelves is an essential observation for the study of the Earth's ice sheets. However, in some locations, such as the Antarctic Peninsula, where many grounding lines have not been mapped since the 1990s, remote sensing of grounding line position remains challenging. Here we present a tidal motion offset correlation (TMOC) method for measuring the grounding line position of tidewater glaciers and ice shelves, based on the correlation between tide amplitude and synthetic aperture radar offset tracking measurements. We apply this method to the Antarctic Peninsula Ice Sheet to automatically delineate a new grounding line position for 2019–2020, with near complete coverage along 9300 km of coastline, updating the 20-year-old record. A comparison of the TMOC grounding line to contemporaneous interferometrically measured grounding line position shows the method has a mean seaward offset compared to interferometry of 185 m and a standard deviation of 295 m. Our results show that over the last 24 years there has been grounding line retreat at a number of fast-flowing ice streams on the Antarctic Peninsula, with the most retreat concentrated in the north-eastern sector, where grounding lines have retreated following the collapse of ice shelves. We observe a maximum grounding line retreat since 1996 of 16.3 ± 0.5 km on Hektoria Glacier, with other notable glaciers retreating by 9.3 ± 0.5, 9.1 ± 0.5 and 3.6 ± 0.5 km. Our results document dynamic change on Antarctic Peninsula glaciers and show the importance of using an updated grounding line location to delineate the boundary between floating and grounded ice.

Validation of computer vision technology for analyzing bradykinesia in outpatient clinic videos of people with Parkinson's disease

BackgroundCurrent diagnosis and monitoring of Parkinson's disease (PD) is based on subjective clinical assessments. Objective measures of motor functioning could support clinical acumen. Computer vision (CV) technology is a promising contactless technique but requires further validation. AimTo investigate the performance of CV analysis of clinic-based videos of finger-tapping. Our goals were (i) to distinguish PD from healthy controls (HC), when compared to human raters, (ii) to measure the severity of bradykinesia, and (iii) detect ON/OFF medication state. MethodsVideos of thirty-one persons with PD and forty-nine HC were collected during clinical outpatient visits. Videos were analysed using CV to produce speed, amplitude, rhythm and composite bradykinesia measures. All videos were independently rated by three raters using the Movement Disorder Society Unified Parkinson's Disease Rating Scale (MDS-UPDRS) and Modified Bradykinesia Rating Scale (MBRS). Twenty video pairs were conducted in ON and OFF states. Classification accuracy for PD/HC state and ON/OFF state were measured using the Area under Receiver Operating characteristic curve and a confusion matrix. CV and clinical measures were correlated using Spearman coefficients. ResultsCV classified disease state with higher accuracy than clinical raters (91 % sensitivity; 97 % specificity). CV measures of bradykinesia correlated significantly with clinical ratings: R = 0.740 for MDS-UPDRS, 0.715 for MBRS speed, 0.714 for amplitude and 0.504 for rhythm. CV classified ON/OFF state as accurately as clinical raters. DiscussionCV can provide a valid, objective and contactless bradykinesia assessment based on clinically collected videos, which offers promise as a new clinical outcome, including in remote settings.

Measurement of Electron Antineutrino Oscillation Amplitude and Frequency via Neutron Capture on Hydrogen at Daya Bay.

This Letter reports the first measurement of the oscillation amplitude and frequency of reactor antineutrinos at Daya Bay via neutron capture on hydrogen using 1958days of data. With over 3.6million signal candidates, an optimized candidate selection, improved treatment of backgrounds and efficiencies, refined energy calibration, and an energy response model for the capture-on-hydrogen sensitive region, the relative ν[over ¯]_{e} rates and energy spectra variation among the near and far detectors gives sin^{2}2θ_{13}=0.0759_{-0.0049}^{+0.0050} and Δm_{32}^{2}=(2.72_{-0.15}^{+0.14})×10^{-3} eV^{2} assuming the normal neutrino mass ordering, and Δm_{32}^{2}=(-2.83_{-0.14}^{+0.15})×10^{-3} eV^{2} for the inverted neutrino mass ordering. This estimate of sin^{2}2θ_{13} is consistent with and essentially independent from the one obtained using the capture-on-gadolinium sample at Daya Bay. The combination of these two results yields sin^{2}2θ_{13}=0.0833±0.0022, which represents an 8% relative improvement in precision regarding the Daya Bay full 3158-day capture-on-gadolinium result.

Empatica E4 Assessment of Child Physiological Measures of Listening Effort During Remote and In-Person Communication.

Telepractice is a growing service model that delivers aural rehabilitation to deaf and hard-of hearing children via telecommunications technology. Despite known benefits of telepractice, this delivery approach may increase patients' listening effort (LE) characterized as an allocation of cognitive resources toward an auditory task. The study tested techniques for collecting physiological measures of LE in normal-hearing (NH) children during remote (referred to as tele-) and in-person communication using the wearable Empatica E4 wristband. Participants were 10 children (age range: 9-12 years old) who came to two tele- and two in-person weekly sessions, order counterbalanced. During each session, the children heard a short passage read by the clinical provider, completed an auditory passage comprehension task, and self-rated their effort as a part of the larger study. Measures of electrodermal activity and blood volume pulse amplitude were collected from the child E4 wristband. No differences in child subjective, physiological measures of LE or passage comprehension scores were found between in-person sessions and telesessions. However, an effect of treatment duration on subjective and physiological measures of LE was identified. Children self-reported a significant increase in LE over time. However, their physiological measures demonstrated a trend indicating a decrease in LE. A significant association between subjective measures and the passage comprehension task was found suggesting that those children who reported more effort demonstrated a higher proportion of correct responses. The study demonstrated the feasibility of collection of physiological measures of LE in NH children during remote and in-person communication using the E4 wristband. The results suggest that measures of LE are multidimensional and may reflect different sources of, or cognitive responses to, increased listening demand. https://doi.org/10.23641/asha.27122064.

Analysis of difficult flotation mechanisms for coarse low-rank coal: Comparing fluidized-bed and mechanical flotation technologies

Efficient flotation of coarse low-rank coal is essential for enhancing energy utilization in the mineral processing industry. As the beneficiation equipment scales up, the precision of particle size classification before flotation decreases, leading to a higher coarse particle content in the feed, which poses significant challenges to traditional flotation processes. Recent advancements in fluidized bed flotation technology have demonstrated considerable advantages in the flotation of coarse-grained metallic minerals; however, its application to coarse low-rank coal remains relatively unexplored. This study investigates the potential of fluidized bed flotation technology for coarse low-rank coal, employing various analytical methods to elucidate difficult flotation mechanisms. Scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) were utilized to comprehensively characterize the surface morphology and chemical composition of coal samples. The influence of increasing particle size on flotation performance was systematically assessed through measurements of induction time and critical detachment amplitude. Comparative flotation experiments were conducted to evaluate the efficacy of traditional mechanical flotation against fluidized bed flotation technologies. Results indicate that the presence of cracks and oxygen-containing functional groups on the coal surface significantly enhances hydrophilicity, hindering flotation recovery rates. With increasing particle size, the induction time between particles and bubbles lengthens, while the critical detachment amplitude decreases, weakening the attachment and increasing detachment likelihood. Although high-efficiency collectors enhance coal particle hydrophobicity, they cannot fully mitigate the turbulence disrupting bubble-particle interactions in mechanical flotation. Conversely, fluidized bed flotation effectively minimizes turbulence interference, leading to an approximate 40 % increase in the recovery rate of coarse low-rank coal (0.25–1.00 mm) compared to traditional mechanical flotation. This study presents a novel technological approach for the efficient recovery of coarse low-rank coal, contributing to the clean utilization of low-rank coal resources.

Resonant frequencies of multi-layer building constructions: Estimation by measurement of acceleration amplitudes

The Austrian building regulation requirements for impact sound insulation are based on the weighted standardized impact sound pressure level as single-number specification. In recent years, it has become apparent that not only the single-number specification, but the extended frequency range and frequency characteristics of impact sound insulation of constructions can have noticeable influence on the perceived acoustic performance of a construction. Therefore, the Austrian Classification Standard ÖNORM B 8115-5: 2021-04 includes extended requirements on impact sound insulation. It provides two ways for verification of the sound insulation classes A to C. One way is the verification via the resonance frequency of multi-layer constructions. However, there exist as yet no standardized measurement methods for the estimation of the resonance frequency of multi-layer building constructions. In response, in course of this study a new measurement method for the estimation of the resonance frequencies of multi-layer constructions was developed. For this development acceleration measurements were carried out on both surfaces of particularly double-layer building constructions, that were excited with a rubber hammer. From these measurement results, in conjunction with an analytical model, it was possible to derive a measurement method for estimating the resonant frequency via the frequency characteristics of the acceleration amplitudes.

Fusional Vergence amplitude measurement among students of ISRA School of optometry, Isra University, Karachi campus

Purpose: To determine mean fusional vergence amplitudes FVA and the effect age and gender on FVA. Methodology: A cross sectional descriptive study was conducted among Isra School of optometry, Isra University, Karachi campus students from August 2023 to December 2023. A total of 120 students consisting of 43 males (35.8%) and 77 females (64.1%) were recruited using a convenient sampling technique. Inclusion criteria included subjects with 6/6 vision, no any ocular disease, strabismus and subjects with exophoria or esophoria. The age ranged from 18-27 years. Patients underwent ophthalmic procedure i.e. visual acuity for both distance and near and ophthalmoscopy was performed to check the clarity of the patient’s media. After assessing the ocular media, cover test was used to check the type of phoria. By using horizontal prism bars, Positive Fusion Vergence (PFV) and Negative Fusion Vergence (NFV) were recorded as break, and recovery points at near and distance. All the information was recorded in self-made Performa. Data was analyzed using SPSS. Result: Students were categorized into three age groups: Group 1 (18-21 years), Group 2 (22-24 years), and Group 3 (25-27 years). The data showed negative fusional divergence break-up and recovery points at distance and near, with mean values of 10.06±4.8 Δ and 7.3±4.7 Δ, respectively. Positive fusional convergence break-up and recovery points at distance and near had mean values of 10.95±6.11 Δ and 8.1±5.57 Δ, respectively. The result for negative divergence break and recovery point at distance were significant with p-value of 0.021 and 0.026, respectively Conclusion: This study concluded that the mean fusional vergence amplitudes FVA at near and distance are reduced while distance and near FV revealed no effects of age and gender. However, negative fusional break point and positive fusional recovery point were significantly affected by age.