HYDRAULIC MACHINES FOR SEPARATION OF WET DISPERSED SYSTEMS

Separation processes of wet dispersed systems are quite common in the food, processing and other industries. In particular, these include processes related to the production of fruit and vegetable juices, jams, sunflower and olive oil, the extraction of fat from meat rinds in meat production, the separation of whey from cheese mass in the production of cheese, the separation of grated cocoa into butter and pulp, dehydration of wet dispersed waste of food production (alcohol grain, beer pellets, beet pulp, coffee and barley sludge). These processes are quite energy-intensive and have low-productivity, therefore, much attention is paid for modernization of equipment for their implementation in the direction of improving the indicated efficiency characteristics, as well as increasing reliability and reducing material consumption, complexity and price of working machines. At the same time, the known hydraulic static presses do not provide of low final moisture content of the product and the required productivity of the working process. Vibratory pressing equipment is often quite complex, unreliable and generates intense noise and vibration during of operation. Screw presses with an electromechanical drive, despite of their advantages, do not allow to achieve of the necessary degree of separation of the components of the dispersed system, in addition, their actuators are structurally quite complex and wear out quickly. The authors propose improved schemes of hydraulic presses for separation of wet dispersed systems, which can provide high rates of efficiency of the working process and have a simple and reliable design. The article also presents equations for calculating of the main operating parameters of the proposed equipment.

Transient peripheral vestibular hypofunction measured with vestibular short-latency evoked potentials following noise exposure in rats

Exposure to 120 decibel sound pressure level (dB SPL) band-limited noise results in delayed onset latency and reduced vestibular short-latency evoked potential (VsEP) responses. These changes are still present four weeks after noise overstimulation. Noise induced hearing loss (NIHL) has been shown to vary in extent and duration based on noise intensity. This study investigated whether noise-induced peripheral vestibular hypofunction (NPVH) would also decrease in extent and/or duration with less intense noise exposure. In the present study, rats were exposed to a less intense noise (110dB SPL), but for the same duration (6 hours) and frequency range (500-4000 Hz) as used in previous studies. The VsEP was assessed 1, 3, 7, 14, 21, and 28 days after noise exposure. In contrast to 120 dB SPL noise exposure, the 110 dB SPL noise exposures produced smaller deficits in VsEP responses that fully recovered in 62% of animals (13/21) within one week. These findings suggest that NPVH, a loss or attenuation of VsEP responses with a requirement for elevated stimulus intensity to elicit measurable responses, is similar to NIHL, i.e., lower sound levels produce a smaller or transient deficit. These results show it will be important to determine the extent and duration of vestibular hypofunction for different noise exposure conditions and their impact on balance.

Tip Vortex Cavitation and Induced Noise Characteristics of Hydrofoils

Tip vortex cavitation is one of the most classical themes in fluid mechanics. Although many experimental and theoretical studies have been performed, unsolved problems still remain. In particular, the trailing vortices at the tip of the hydrofoil directly affects the hydrodynamic and acoustic performance of submerged objects such as the marine propeller, rudder and various foil-shaped appendages of the ship. In this study, the experimental results from the measurements of the vortex cavitation from the tip of two different three-dimensional hydrofoils are presented. Experiments have been carried out in Chungnam National University-Cavitation Tunnel (CNU-CT). By high speed imaging technique, the development process of vortex cavitation is observed in detail. Based on the high-speed images, physical features of the cavity inception and the swirling motion of the tip vortex cavity flow are examined. In addition, the induced noise characteristics in the vortex development process are examined by unsteady pressure measurements. The forces exerted on the hydrofoil were also measured using a dynamometer with a view to verify the scaling relation between the inception cavitation number and the non-dimensional parameters namely, the coefficient of lift, CL and the Reynolds number, Re. The results further shed light on the cause of the intense noise induced by tip vortex cavitation.

Noise-Induced Hearing Loss (NIHL) Risk Factors among Manufacturing Industry Workers: A Systematic Review

Introduction : Noise-Induced Hearing Loss (NIHL) is an occupational disease caused by continuous long-term acute exposure to intense noise with a noise intensity level higher than 85 dB(A). Noise being one of the potential hazard in the workplace, is the most common risk factor for health problems (22%), after workplace injuries (40%). The aim of this work is to synthesize evidence on risk factors related to NIHL among the manufacturing industries workers. Methods: This systematic review was conducted in the electronic search trough databases: SCIENCE DIRECT, PUBMED and GOOGLE SCHOLAR using appropriate keywords related to the theme. The keywords used in the databases were: “faktor risiko noise induced hearing loss” “industri” for national database, “noise induced hearing loss” AND “risk factors’’ AND “industry” for international databases. Results: 1.175 studies were identified from the search, thus 1.049 were screened following the removal of duplicates. Title and abstract were screened, resulting in 1.049 articles being removed, 212 articles left for full text assessment and 20 articles met the inclusion criteria. Conclusion: Risk factors for NIHL among manufacturing industry workers include noise intensity, years of service, duration of exposure (hours), age, hypertension, risk behaviors and Hearing Protection Device (HPD) usage.

Evaluation of vestibular functions and balance in edirne band musicians

BACKGROUND: It has been found that intense noise may affect the peripheral vestibular system and consequently causes problems in balance mechanisms. OBJECTIVE: The aim of this study was to investigate the effects of exposure to chronic noise on vestibular functions and balance in Edirne Band musicians. METHODS: Twenty-two individuals working in the Edirne Band for at least 5 years and a control group of 22 individuals working at Trakya University with similar sociodemographic characteristics were included. The socio-demographic questionnaire was used to inquire about the demographic characteristics of individuals, the ABC Scale to assess how they felt about the balance, and the DHI to determine the quality of life related to dizziness. A 3D ultrasonic system was used to assess the static and dynamic balance of the individuals. RESULTS: There was a statistically significant difference between the band and the control group in terms of longitudinal deviation and self-spin parameters of the Unterberger test, dizziness handicap inventory scores, functional balance according to activity-specific balance confidence scale (p < 0.05). CONCLUSIONS: As a result of our study, it has been shown that the balance, quality of life and vestibular system functions are negatively affected in the band exposed to noise for a long time.

Precise positioning is known as a loxodrome on a trajectory on navigation measurements with intense noise

The article proposes a method of improving the accuracy of determining the current coordinates of a moving object moving along a loxodromic trajectory by analytical three-dimensional projection of its coordinates determined by navigation measurements in conditions of intense interference on the trajectory of its true motion. The results of testing the efficiency of the proposed method, which was carried out by numerical simulation of the algorithms described in the work of determining the coordinates of the object on the loxodromic trajectory on noisy navigation measurements. The results indicates the possibility of effective use of the proposed approach. Keywords: analytical three-dimensional projection coordinates, geographic information systems, interference, known as a loxodrome path, navigation measurement.

COMPREHENSIVE ASSESSMENT OF THE IMPACT OF AIR NOISE AND DUST ON FOUNDRY OPERATORS

The main goal of the work is a comprehensive assessment of the impact of noise and dust in the foundry. Based on the results of the analysis, the main disadvantage areas with exceeding the permissible noise and dust level are presented – areas of knockout grates and casting cleaning areas. Recommendations are proposed for the selection of technical measures, including the rational placement of equipment, their mode of operation, the installation of acoustic screens and sound-insulating partitions near unprotected workplaces, as well as a rational selection of the equivalent sound absorption area of the workshop premises, which will create safe production conditions. Ways of improving the working conditions of operators of sand and shot blasting installations by reducing noise at their workplaces are considered: increasing sound absorption in the body of the shot blasting chamber and installing noise-protective shielding structures to fence off areas with the most intense noise.

FEATURES OF HELICOPTER NOISE AND HEALTH RISKS

The generated noise of the Mi-8 helicopter will differ significantly in the mechanism of formation, resulting in a complex spectrum. Working conditions inside the helicopter correspond to harmful working conditions in terms of noise (class 3.2 – 3.3), and in terms of infrasound – acceptable (class 2). The simultaneous effect of intense noise, infrasound and General vibration creates high risks to the health of helicopter personnel.

An Antinoise Fault Diagnosis Method Based on Multiscale 1DCNN

The bearing state signal collected by the vibration sensor contains a large amount of environmental noise in actual processes, which leads to a reduction in the accuracy of the convolutional network in identifying bearing faults. To solve this problem, a one-dimensional convolutional neural network with a multiscale kernel (MSK-1DCNN) is proposed for the classification information enhancement of the input. A two-layer multiscale convolution structure (MSK) is used at the front of the network. MSK has five convolutional kernels with different sizes, and those kernels are used to extract features with varying resolutions in the original signal. In the multiscale convolution structure, the ELU activation function is used instead of the ReLU function to improve the antinoise ability of MSK-1DCNN, also by adding pepper noise to the training set data to destroy the input data and forcing the network to learn more representative features to improve the robustness of the network. Experimental results illustrate that the improved methods proposed in this paper effectively enhance the diagnostic performance of MSK-1DCNN under intense noise, and the diagnostic accuracy is higher than that of other comparison algorithms.