scholarly journals Vibration related symptoms and signs in quarry and foundry workers

2021 ◽  
Author(s):  
Lars Gerhardsson ◽  
Christina Ahlstrand ◽  
Per Ersson ◽  
Per Jonsson ◽  
Ewa Gustafsson
Keyword(s):  
High Frequency ◽  
Vascular System ◽  
Vibration Exposure ◽  
Contributing Factors ◽  
Work Tasks ◽  
High Prevalence ◽  
High Frequency Vibrations ◽  
Low Prevalence ◽  
Foundry Workers

Abstract Purpose The development of vascular and neurosensory findings were studied in two groups of long-term exposed quarry and foundry workers with different vibration exposures, working conditions and work tasks. Methods The study included 10 quarry workers (mean age 43 yrs., mean exposure time 16 yrs.) and 15 foundry workers (35 yrs.; 11 yrs.) at two plants in Sweden. All participants completed a basic questionnaire and passed a medical examination including a number of neurosensory tests, e.g. the determination of vibration (VPT) and temperature (TPT) perception thresholds as well as a musculoskeletal examination of the neck, shoulders, arms and hands. Results A high prevalence of neurosensory findings (40%) was found among the quarry workers. Both groups, however, showed a low prevalence of vibration white fingers (VWF). Foundry workers showed significantly better sensitivity than quarry workers for all monofilament tests (p ≤ 0.016), TPT warmth in dig 2 (p = 0.048) and 5 dexter (p = 0.008), and in dig 5 sinister (p = 0.005). They also showed a better VPT performance in dig 5 dexter (p = 0.031). Conclusions Despite high vibration exposure, the prevalence of VWF was low. The high prevalence of neurosensory findings among the quarry workers may depend on higher A(8) vibration exposure and higher exposure to high-frequency vibrations. An age-effect and exposure to cold could also be contributing factors. The nervous system seems to be more susceptible to high-frequency vibrations than the vascular system. For neurosensory injuries, the current ISO 5349-1 standard is not applicable.

Identification of Small Amplitude Resonances in Rotary Digital Systems

1988 ◽  
Vol 202 (1) ◽  
pp. 63-65 ◽  
Author(s):  
J D Smith
Keyword(s):  
High Frequency ◽  
Small Amplitude ◽  
Digital Systems ◽  
High Frequency Vibrations

A method is described for determination of amplitudes of high-frequency vibrations of a system when the level of vibration is less than the discrimination of the system. This allows identification of torsional resonances in rotary encoders used to measure gear vibrations.

Simulation of vibration piercing of pipe blank at press

2020 ◽  
Vol 76 (11) ◽  
pp. 1128-1138
Author(s):  
S. R. Rakhmanov
Keyword(s):  
High Frequency ◽  
Deformation Zone ◽  
Pipe Blank ◽  
Equipment Operation ◽  
Metal Deformation ◽  
Technological Tool ◽  
High Frequency Vibrations ◽  
Pipe Blanks ◽  
Wave Phenomena

In some cases, the processes of piercing or expanding pipe blanks involve the use of high-frequency active vibrations. However, due to insufficient knowledge, these processes are not widely used in the practice of seamless pipes production. In particular, the problems of increasing the efficiency of the processes of piercing or expanding a pipe blank at a piercing press using high-frequency vibrations are being solved without proper research and, as a rule, by experiments. The elaboration of modern technological processes for the production of seamless pipes using high-frequency vibrations is directly related to the choice of rational modes of metal deformation and the prediction resistance indicators of technological tools and the reliability of equipment operation. The creation of a mathematical model of the process of vibrating piercing (expansion) of an axisymmetric pipe blank at a piercing press of a pipe press facility is an actual task. A calculation scheme for the process of piercing a pipe plank has been elaborated. A dependence was obtained characterizing the speed of front of plastic deformation propagation on the speed of penetration of a vibrated axisymmetric mandrel into the pipe workpiece being pierced. The dynamic characteristics of the occurrence of wave phenomena in the metal being pierced under the influence of a vibrated tool have been determined, which significantly complements the previously known ideas about the stress-strain state of the metal in the deformation zone. The deformation fields in the zones of the disturbed region of the deformation zone were established, taking into account the high-frequency vibrations of the technological tool. It has been established that the choice of rational parameters (amplitude-frequency characteristics) of the vibration piercing process of a pipe blank results in significant increase in the efficiency of the process, the durability of the technological tool and the quality of the pierced blanks.

Clinical and anamnestic characteristics of patients with adenomyosis, accompanied by pelvic pain syndrome

GYNECOLOGY ◽  
2018 ◽  
Vol 20 (6) ◽  
pp. 77-80
Author(s):  
M R Orazov ◽  
V E Radzinsky ◽  
M B Khamoshina ◽  
A O Dukhin ◽  
L R Toktar ◽  
...  
Keyword(s):  
Pelvic Pain ◽  
Chronic Pelvic Pain Syndrome ◽  
Pain Syndrome ◽  
Reproductive Age ◽  
Pelvic Pain Syndrome ◽  
Common Disease ◽  
Contributing Factors ◽  
High Prevalence ◽  
Inflammatory Processes ◽  
History Of

Pelvic pain syndrome associated with adenomyosis is a common disease in women of reproductive age. Frequency of detection in the population varies from 10 to 53%. The aim - to study the clinical and anamnestic risk factors of pelvic pain, with adenomiose. Materials and methods. The study included 120 (n=120) patients with diffuse adenomyosis with pain and painless form of the disease who underwent examination and treatment in the gynecological Department of the Central clinical hospital №6 of Russian Railways in Moscow. Each patient was provided with an individual card, which was encrypted 171 sign. The studied parameters reflected the passport and anthropometric data, information about education, social status, presence of occupational hazards, complaints, illness. Results. Burdened gynecological and somatic histories, manifested a low health index, a more pronounced hereditary a family history of neoplastic diseases are contributing factors, and high prevalence of postponed surgeries, chronic, long-term ongoing inflammatory processes of the pelvic organs to create a favorable background for the further progression of chronic pelvic pain syndrome in adenomiose.

scholarly journals Changes in contraception use among Brazilian women after childbirth, 2006-2013

2020 ◽  
Vol 30 (Supplement_5) ◽  
Author(s):  
M Felisbino-Mendes ◽  
B Barrozo Siqueira
Keyword(s):  
Health System ◽  
Secondary Data ◽  
Reproductive Age ◽  
Cross Sectional ◽  
Regional Inequalities ◽  
Unified Health System ◽  
Contraception Use ◽  
High Prevalence ◽  
Modern Methods ◽  
Low Prevalence

Abstract Introduction There are gaps in knowledge regarding the neglected and vulnerable subgroups of FP actions in Brazil, such as postpartum women and women in general, regardless of their marital status. Objective To assess changes in the prevalence of use and in the contraceptive pattern of Brazilian women up to two years after pregnancy, between 2006 and 2013. Methods Cross-sectional, descriptive and analytical study which used secondary data from national surveys. We studied Brazilian women with up to 2 years postpartum, of reproductive age, sexually active, non-pregnant and menstruating, and compared them with all the other women. We estimated the prevalence of use, contraception pattern of contraception and ranking of modern methods. Percentual change in indicators between the years was evaluated by calculating the difference between estimates. Results 85% of Brazilian women used CM, remaining stable in 2006 and 2013, with a high prevalence of modern methods use. An increase in the use of CM was observed among those with up to six months postpartum (71.0% to 89.0%). Pills and condoms accounted for about 60% of modern methods used in the postpartum period in both surveys. There was an increase in dual protection (2.9% to 10.1%) and contraceptive insecurity (1.6% to 5.7%) and a reduction in sterilization (16.2% to 13.4%) and traditional methods (2.1% to 1.4%). Conclusions Even with the maintenance of a high prevalence of use of CM and with the increase in contraception among women with up to six months postpartum, regional inequalities in access to CM and low prevalence of the use of other methods made available by the Unified Health System (SUS) persist, pointing out the maintenance of the insufficient care, failures in the means to regulate fertility and that public policies still hinder to guarantee the sexual and reproductive rights of the most vulnerable population. Key messages Regional inequalities in access to contraceptive methods and low prevalence of other methods made available by the Unified Health System (SUS) persist. There was an increase in contraception use among women with up to six months postpartum in Brazil.

Analytical Solution for Rotational Rub-Impact Plate Under Thermal Shock

2016 ◽  
Vol 32 (3) ◽  
pp. 297-311
Author(s):  
T.-Y. Zhao ◽  
H.-Q. Yuan ◽  
B.-B. Li ◽  
Z.-J. Li ◽  
L.-M. Liu
Keyword(s):  
Thermal Shock ◽  
High Frequency ◽  
Equations Of Motion ◽  
Low Frequency ◽  
Cantilever Plate ◽  
Analysis Method ◽  
Multiple Frequency ◽  
Width Direction ◽  
Blade Tip ◽  
High Frequency Vibrations

AbstractThe analysis method is developed to obtain dynamic characteristics of the rotating cantilever plate with thermal shock and tip-rub. Based on the variational principle, equations of motion are derived considering the differences between rubbing forces in the width direction of the plate. The transverse deformation is decomposed into quasi-static deformation of the cantilever plate with thermal shock and dynamic deformation of the rubbing plate under thermal shock. Then deformations are obtained through the calculation of modal characteristics of rotating cantilever plate and temperature distribution function. Special attention is paid to the influence of tip-rub and thermal shock on the plate. The results show that tip-rub has the characteristics of multiple frequency vibrations, and high frequency vibrations are significant. On the contrary, thermal shock shows the low frequency vibrations. The thermal shock makes the rubbing plate gradually change into low frequency vibrations. Because rub-induced vibrations are more complicated than those caused by thermal shock, tip-rub is easier to result in the destruction of the blade. The increasing friction coefficient intensifies vibrations of the rubbing plate. Minimizing friction coefficients can be an effective way to reduce rub-induced damage through reducing the surface roughness between the blade tip and the inner surface of the casing.

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