A coupled acoustic/elastic discontinuous Galerkin finite element method: Application to ultrasonic imaging of 3D-printed synthetic materials

International audienceWe present the derivation of upwind numerical fluxes for the space discontinuous Galerkin (dG) finite element method applied to the numerical modeling of wave propagation in multidimensional coupled acoustic/elastic media. The space dG method is formulated using the first-order velocity-pressure and velocity-stress systems for acoustic and elastic media, respectively. After eigenanalysis of the first-order hyperbolic systems highlighting the eigenmodes of wave propagation, the upwind numerical fluxes on the acoustic/acoustic and acoustic/elastic interface are obtained in terms of exact solutions of relevant Riemann problems. Thanks to the proposed approach, explicit closed-form expressions of the upwind numerical fluxes are obtained on the acoustic/elastic interface for the general case of multidimensional anisotropic heterogeneous solid media coupled with acoustic fluids. The developed numerical fluxes are validated by analytical/numerical comparison considering the example of an acoustic domain with a circular elastic inclusion. Finally, the coupled solver is used to perform a multiparametric study on the microstructure’s echogenicity in a 3D-printed synthetic material under ultrasonic imaging

Postural Loading Assessment in Assembly Workers of an Iranian Telecommunication Manufacturing Company

Background. Changes in industries and work practices have coincided with work-related musculoskeletal disorders(MSDs). This study was conducted to determine the prevalence of MSDs and to assess postural loading in assembly workers of an Iranian telecommunication manufacturing company. Methods. Data were collected from 193 randomly selected workers in 4 units of the company. The Nordic musculoskeletal disorders questionnaire and the UBC ergonomic checklist were used as data collection tools. Loading on the upper body assessment(LUBA) was used to assess postural loading. Results. Lower back symptoms were the most prevalent problems among the workers (67.9%). LUBA showed that most assembly workers (94.3%) had experienced considerable and high postural loading (postural load index, PLI > 5). Regression analyses revealed that lighting, rotation, contact stress, repetition, gender and age were factors associated with symptoms. Conclusion. Work-related MSDs occurred at a high rate among workers. Postural loading requires consideration. Any ergonomic intervention should focus on eliminating ergonomic factors associated with symptoms

Postural Loading Assessment in Assembly Workers of an Iranian Telecommunication Manufacturing Company

Background. Changes in industries and work practices have coincided with work-related musculoskeletal disorders(MSDs). This study was conducted to determine the prevalence of MSDs and to assess postural loading in assembly workers of an Iranian telecommunication manufacturing company. Methods. Data were collected from 193 randomly selected workers in 4 units of the company. The Nordic musculoskeletal disorders questionnaire and the UBC ergonomic checklist were used as data collection tools. Loading on the upper body assessment(LUBA) was used to assess postural loading. Results. Lower back symptoms were the most prevalent problems among the workers (67.9%). LUBA showed that most assembly workers (94.3%) had experienced considerable and high postural loading (postural load index, PLI > 5). Regression analyses revealed that lighting, rotation, contact stress, repetition, gender and age were factors associated with symptoms. Conclusion. Work-related MSDs occurred at a high rate among workers. Postural loading requires consideration. Any ergonomic intervention should focus on eliminating ergonomic factors associated with symptoms

Eleven year epidemiological study of tuberculosis in Golestan Province, Northern of Iran

Background: At present, researchers were aimed at exploring the epidemiology of tuberculosis (TB) in Golestan Province in North of Iran that usually ranks 2nd or 1st, alternatively. Methods: An epidemiological study of 11 years was carried out over 8405 patients with TB from 2005 to 2014 years. Data were collected from Health System of the Ministry of Health in Iran using a patient-sheet. Descriptive statistics were applied to report the results. Results: Of those screened, the vast majority of patients with newly diagnosed smear-positive 1799 (41.6) and smear-positive with relapse 203 (56.5) were referred from Health System (outpatient cases). Given the newly diagnosed TB, 3559 and 264 of smear-positive were treated and died, respectively; while, 1196 and 119 of smearnegative cases were accordingly treated completely and died. Conclusion: The vast majority of TB cases are infected by pulmonary TB, educational preventive programs seem likely more useful to control the disease. © 2020, Iranian Journal of Public Health. All rights reserved

Pediatric Cutaneous Leishmaniasis in Golestan Province, Iran: A Cross-Sectional Study of 8-years

Background: Cutaneous leishmaniasis (CL) is a main public health problem in Iran with a high incidence rate among children. According to numerous studies in Iranian society, the most commonly affected age group is 1-4 years. At present, we aimed to investigate the pediatric CL among children in Golestan Province in North of Iran. Materials and Methods: A cross-sectional study was run on data existed for 3,371 cases with pediatric cutaneous leishmaniasis based on routinely collected data from the Health System of Golestan Province, Iran, between 2010 and 2017. Data of the study were gathered using two checklists about CL and demographic status from District Health Network. Data were analyzed using SPSS software (version 18.0). Results: In general, 337 leases were investigated. The majority of cases were male 1495 (50.9), lived in the rural area, while the least CL were female 155 (38.7 ), and lived in the urban area. Pediatric cutaneous leishmaniasis had the highest 883 (26.3), and lowest 186 (5.5) frequency in 2010 and 2013 years, accordingly. CL was increased from July and reached to maximum in October, then decreased considerably in January. In final, a significant relationship was found between CL cases and years of the survey (p= 0.001). Conclusion: The most CL cases were found among males and aged 0-5 years. As indicated by different studies, CL in the endemic area of the country (Golestan Province) occurs more often in children, while it commonly happens among adolescents in the central area of the country. Thus, it points to the role of mothers in protecting children through dressing up and sleeping habits in the outdoor environments