Pneumonia is a serious disease often accompanied by complications, sometimes leading to death. Unfortunately, diagnosis of pneumonia is frequently delayed until physical and radiologic examinations are performed. Diagnosing pneumonia with cough sounds would be advantageous as a non-invasive test that could be performed outside a hospital. We aimed to develop an artificial intelligence (AI)-based pneumonia diagnostic algorithm. We collected cough sounds from thirty adult patients with pneumonia or the other causative diseases of cough. To quantify the cough sounds, loudness and energy ratio were used to represent the level and its spectral variations. These two features were used for constructing the diagnostic algorithm. To estimate the performance of developed algorithm, we assessed the diagnostic accuracy by comparing with the diagnosis by pulmonologists based on cough sound alone. The algorithm showed 90.0% sensitivity, 78.6% specificity and 84.9% overall accuracy for the 70 cases of cough sound in pneumonia group and 56 cases in non-pneumonia group. For same cases, pulmonologists correctly diagnosed the cough sounds with 56.4% accuracy. These findings showed that the proposed AI algorithm has value as an effective assistant technology to diagnose adult pneumonia patients with significant reliability.
(1) Background: Non-invasive uroflowmetry is used in clinical practice for diagnosing lower urinary tract symptoms (LUTS) and the health status of a patient. To establish a smart system for measuring the flowrate during urination without any temporospatial constraints for patients with a urinary disorder, the acoustic signatures from the uroflow of patients being treated for LUTS at a tertiary hospital were utilized. (2) Methods: Uroflowmetry data were collected for construction and verification of a long short-term memory (LSTM) deep-learning algorithm. The initial sample size comprised 34 patients; 27 patients were included in the final analysis. Uroflow sounds generated from flow impacts on a structure were analyzed by loudness and roughness parameters. (3) Results: A similar signal pattern to the clinical urological measurements was observed and applied for health diagnosis. (4) Conclusions: Consistent flowrate values were obtained by applying the uroflow sound samples from the randomly selected patients to the constructed model for validation. The flowrate predicted using the acoustic signature accurately demonstrated actual physical characteristics. This could be used for developing a new smart flowmetry device applicable in everyday life with minimal constraints from settings and enable remote diagnosis of urinary system diseases by objective continuous measurements of bladder emptying function.
In the engineering field, severe vibration of the pipeline system occurs under random excitation, which leads to vibration failure of the pipeline system due to overload. The traditional method is to increase the rigidity of the pipeline system, and to avoid low-frequency resonance by using clamps or damping materials. However, due to structural limitations, it is difficult to apply clamps and damping materials. Particle damping technology has been applied in many fields, and the vibrational energy in the broadband frequency domain could be dissipated based on nonlinear particle collision damping. In this paper, a particle impact damper is designed for vibration reduction of the pipeline system. The damping capability is identified to investigate the effects of particle material, filling rate, particle size, damper structure, and boundary conditions. The results indicate that the ideal damping performance can be obtained by properly selecting particle parameters. Based on applying particle damping on the pipeline system, the proposed particle impact damper showed excellent damping capability under random excitation.
The structure of pipeline systems is complex, and the working environment is harsh. Under the excitation of the engine equipment foundation and pump fluid, it is easy to generate excessive vibration, which seriously affects the safe operation of the equipment. Particle damping achieves structural vibration suppression through the principle of particle collision dissipation. Due to the drawbacks of traditional pipeline vibration reduction methods, this article introduces a particle damping technology for pipeline system vibration suppression and designs particle dampers based on the structural characteristics of pipelines. We analyzed the energy dissipation mechanism of particle damping, revealed the influence of the materials, structure, external excitation, and other parameters of the pipeline particle dampers on the energy dissipation characteristics of the particle damping, established a pipeline vibration reduction test system with particle damping, and verified its effectiveness in pipeline system vibration reduction. This study can provide a technical reference for vibration reduction in pipeline systems.
A multi-branch pipeline is a typical structure, which is widely used in aerospace, marine and other hydraulic systems. The multi-branch pipeline suffers serious vibration from fluid–structure interaction, which can cause vibration failures in the pipeline system through overload in engineering fields. Vibrational analysis of the multi-branch pipeline system is increasing as part of the design of hydraulic system. In this paper, the finite element model of a multi-branch pipeline considering fluid—structure interaction is established, and the effectiveness of the modeling is validated through a comparison of the modal test for a typical four-way pipeline. The effects of the flow rate, pressure, fluid medium, pipe diameter, elastic constraint stiffness, and pipeline length and wall thickness on the dynamic characteristics of pipeline system are all considered. The obtained results indicate that the multi-branch junction suffering from significant vortex fluid is the main cause of fluid-induced vibration of the pipeline system. The fluid and structural parameters have great influence on the vibration characteristics of the pipeline, which can serve as an efficient tool in the design and maintenance of multi-branch hydraulic pipeline systems.
The base excitation of mechanical equipment can result in pipeline system vibration which seriously affects the safe operation of the equipment. Particle damping technology is based on the particle collision dissipation principle to realize the structural vibration energy dissipation. This paper introduces the particle damping method into the vibration control of pipeline system. A particle damper has been designed for the structural characteristics of the pipeline. The influence of the material and structure of the pipeline particle damper, the external excitation and other parameters on the energy dissipation characteristics of particle damping are revealed. The energy dissipation mechanism of the pipeline particle collision damper under various parameter is analyzed. A pipeline vibration reduction test system with particle damping has been established. The effects of different excitation conditions, damper materials and number of unit structures of particle damper on the vibration damping effect of pipeline systems are investigated comparatively. The influence of damper parameters on the vibration suppression of pipeline system is obtained. The research in this paper can provide technical references for vibration suppression of pipeline systems.