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1.
Sensors (Basel) ; 21(16)2021 Aug 13.
Artigo em Inglês | MEDLINE | ID: mdl-34450902

RESUMO

This study aims at evaluating the efficiency of sensor fusion, based on neural networks, to estimate the microstructural characteristics of both the weld bead and base material in GMAW processes. The weld beads of AWS ER70S-6 wire were deposited on SAE 1020 steel plates varying welding voltage, welding speed, and wire-feed speed. The thermal behavior of the material during the process execution was analyzed using thermographic information gathered by an infrared camera. The microstructure was characterized by optical (confocal) microscopy, scanning electron microscopy, and X-ray Diffraction tests. Finally, models for estimating the weld bead microstructure were developed by fusing all the information through a neural network modeling approach. A R value of 0.99472 was observed for modelling all zones of microstructure in the same ANN using Bayesian Regularization with 17 and 15 neurons in the first and second hidden layers, respectively, with 4 training runs (which was the lowest R value among all tested configurations). The results obtained prove that RNAs can be used to assist the project of welded joints as they make it possible to estimate the extension of HAZ.


Assuntos
Soldagem , Teorema de Bayes , Microscopia Eletrônica de Varredura , Redes Neurais de Computação , Aço
2.
Sensors (Basel) ; 21(16)2021 Aug 18.
Artigo em Inglês | MEDLINE | ID: mdl-34450995

RESUMO

Essential quality features of pressure sensors are, among other accuracy-related factors, measurement range, operating temperature, and long-term stability. In this work, these features are optimized for a capacitive pressure sensor with a measurement range of 10 bars. The sensor consists of a metal membrane, which is connected to a PCB and a digital capacitive readout. To optimize the performance, different methods for the joining process are studied. Transient liquid phase bonding (TLP bonding), reactive joining, silver sintering, and electric resistance welding are compared by measurements of the characteristic curves and long-term measurements at maximum pressure. A scanning electron microscope (SEM) with energy-dispersive X-ray spectroscopy (EDX) analysis was used to examine the quality of the joints. The evaluation of the characteristic curves shows the smallest measurement errors for TLP bonding and sintering. For welding and sintering, no statistically significant long-term drift was measured. In terms of equipment costs, reactive joining and sintering are most favorable. With low material costs and short process times, electric resistance welding offers ideal conditions for mass production.


Assuntos
Prata , Soldagem , Impedância Elétrica , Temperatura
3.
Environ Sci Technol ; 55(16): 11308-11317, 2021 08 17.
Artigo em Inglês | MEDLINE | ID: mdl-34319084

RESUMO

Membrane distillation (MD) is a promising technology for treating the concentrated seawater discharged from the desalination process. Interconnected porous membranes, fabricated by additive manufacturing, have received significant attention for MD technology because of their excellent permeability. However, their poor hydrophobic durability induced by the deformation of pores constrains their water desalination performance. Herein, an in situ three-dimensional (3D) welding approach involving emulsion electrospinning is reported for fabricating robust nanofibrous membranes. The reported method is simple and effective for welding nanofibers at their intersections, and the reinforced membrane pores are uniform in the 3D space. The results show that the in situ 3D welded nanofibrous membrane, with a stability of 170 h and water recovery of 76.9%, exhibits better desalination performance than the nonwelded (superhydrophobic) nanofibrous membrane and the postwelded (superhydrophobic) nanofibrous membrane. Furthermore, the stability mechanism of the in situ 3D welded nanofibrous membrane and the two different wetting mechanisms of the nonwelded and postwelded nanofibrous membranes were investigated in the current work. More significantly, the in situ 3D welded nanofibrous membrane can further concentrate the actual concentrated seawater (121°E, 37°N) to crystallization, demonstrating its potential applications for the desalination of challenging concentrated seawater.


Assuntos
Nanofibras , Soldagem , Destilação , Membranas Artificiais , Água do Mar
4.
Sensors (Basel) ; 21(12)2021 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-34207475

RESUMO

In modern production environments, advanced and intelligent process monitoring strategies are required to enable an unambiguous diagnosis of the process situation and thus of the final component quality. In addition, the ability to recognize the current state of product quality in real-time is an important prerequisite for autonomous and self-improving manufacturing systems. To address these needs, this study investigates a novel ensemble deep learning architecture based on convolutional neural networks (CNN), gated recurrent units (GRU) combined with high-performance classification algorithms such as k-nearest neighbors (kNN) and support vector machines (SVM). The architecture uses spatio-temporal features extracted from infrared image sequences to locate critical welding defects including lack of fusion (false friends), sagging, lack of penetration, and geometric deviations of the weld seam. In order to evaluate the proposed architecture, this study investigates a comprehensive scheme based on classical machine learning methods using manual feature extraction and state-of-the-art deep learning algorithms. Optimal hyperparameters for each algorithm are determined by an extensive grid search. Additional work is conducted to investigate the significance of various geometrical, statistical and spatio-temporal features extracted from the keyhole and weld pool regions. The proposed method is finally validated on previously unknown welding trials, achieving the highest detection rates and the most robust weld defect recognition among all classification methods investigated in this work. Ultimately, the ensemble deep neural network is implemented and optimized to operate on low-power embedded computing devices with low latency (1.1 ms), demonstrating sufficient performance for real-time applications.


Assuntos
Aprendizado Profundo , Soldagem , Algoritmos , Lasers , Redes Neurais de Computação
5.
Artigo em Chinês | MEDLINE | ID: mdl-34218571

RESUMO

Objective: To explore the short-term effects of welding fumes on workers' lung function in the welding environment preliminarily, and provide reference for future research. Methods: In October 2020, the lung function of the subjects was repeatedly measured before and after the working shift with a panel study. The paired t test was used to compare the lung function before and after the shift, and the linear mixed effects model was used to analyze the short-term changes of lung function. Results: 36 male welders were included, and the average age was (30.72±5.21) years, average employed year was (4.36±2.17) years. And the average concentration of welding fume was (1.27±0.49) mg/m(3). The forced vital capacity (FVC) , forced expiratory volume in the first second (FEV1) and peak expiratory flow (PEF) of welders after the shift were significantly lower than those before the shift (t=19.52, 48.13, 62.03, P<0.05) . After adjusting the workers' age, BMI and employed years, the changes of FVC% and FEV1% with the concentration of welding fume were statistically significant (ß=-1.02, 95%CI: -1.54--0.52; ß=-1.56, 95%CI: -1.95--1.16; P<0.01) . In another word, for the 1 mg/m(3) increase of welding fume in the working environment, compared with the baseline, the FVC decreases by 1.02%, and FEV1 decreases by 1.56%. Conclusion: Short-term exposure to welding fumes in workplace can reduce the lung function of welders.


Assuntos
Poluentes Ocupacionais do Ar , Doenças Profissionais , Exposição Ocupacional , Soldagem , Adulto , Humanos , Pulmão , Masculino , Capacidade Vital
6.
Artigo em Inglês | MEDLINE | ID: mdl-34198698

RESUMO

Manufacturing sites, such as welding, casting, and asphalt production (fumes), generate vast numbers of ultrafine particles of <0.1 µm in size and submicron particles close to the ultrafine range (0.1-0.5 µm). Although cumulative masses of these particles are negligible in comparison to the larger particles, the health effects are more severe due to the higher penetration in the human lower respiratory tract, other body parts crossing the respiratory epithelial layers, and the larger surface area. This research investigates the effectiveness of two common commercially available N95 filtering facepieces and N95 pleated particulate respirator models against ultrafine and submicron particles. Two specific types of respirators, the N95 filtering facepiece and the N95 pleated particulate models, in both sealed and unsealed conditions to the manikin face, were tested at various commercial and academic manufacturing sites, a welding and foundry site, and an asphalt production plant. Two TSI Nanoscan SMPS nanoparticle counters were used simultaneously to collect data for particles of 10-420 nm in size from inside and outside of the respirators. While one of them represented the workplace exposure levels, the other one accounted for the exposure upon filtration through the respiratory surfaces. The results showed the particles generated by these manufacturing operations were mostly within the range of from 40 to 200 nm. Results also indicated that while the percentage of filtration levels varied based on the particle size, it remained mostly within the desired protection level of 95% for both of the N95 respirator models in sealed conditions and even for the N95 pleated particulate model in the unsealed condition. However, in the case of the N95 filtering facepiece model, unsealed respirators showed that the percentage of penetration was very high, decreasing the protection levels to 60% in some cases. Although the number of workplace airborne particle levels varied considerably, the filtration percentages were relatively consistent.


Assuntos
Poluentes Ocupacionais do Ar , Exposição Ocupacional , Dispositivos de Proteção Respiratória , Soldagem , Aerossóis/análise , Poluentes Ocupacionais do Ar/análise , Filtração , Humanos , Hidrocarbonetos , Tamanho da Partícula , Material Particulado/análise , Ventiladores Mecânicos , Local de Trabalho
7.
Georgian Med News ; (314): 155-162, 2021 May.
Artigo em Russo | MEDLINE | ID: mdl-34248047

RESUMO

The aim of the study was to develop a new method of formation of biliodigestive anastomoses, which would make it possible to form anastomoses both on unchanged bile ducts and in conditions of their inflammation. An experimental study was carried out on 50 rabbits of the "Chinshila" breed, which formed biliodigestive and interintestinal anastomoses by the method of high-frequency (HF) electric welding using the "Patonmed EKVZ-300" coagulator. Anastomoses were formed both on non-inflamed tissues and under conditions of biliary peritonitis. In different terms after the operation macro- and microscopic examination of the formed anastomoses was carried out, their patency, tightness and strength were determined. With HF-electric welding the connection of biological tissues is achieved due to thermal adhesion, the mucous and serous layers in the area of the anastomosis are almost completely destroyed under the influence of electricity and the connection occurs due to the submucosal layer. The suture is well-established, hermetically sealed, the anastomoses have sufficient strength (40-100 mm Hg). The coagulation scar is narrow, thermal damage to the membranes is local (within 2700-3000 microns), the epithelialization of the suture was completed after 3 months and the maturation of the scar after 6 months. The method of HF-electric welding equally allows the formation of reliable biliodigestive and interintestinal anastomoses, both in conditions of unchanged and inflamed tissues. The everting weld connection prevents the occurrence of anastomotic strictures in the future.


Assuntos
Soldagem , Anastomose Cirúrgica , Animais , Ductos Biliares/cirurgia , Eletricidade , Coelhos , Suturas
8.
J Coll Physicians Surg Pak ; 30(6): 737-739, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-34102794

RESUMO

A descriptive cross-sectional survey was done from January to June 2018 in welding shops of Rawalpindi city, Pakistan. The objectives of the study were to determine the frequency of topical ocular anesthetic use among welders and to assess the knowledge and practices of welders regarding safety measures. One hundred and fifty-eight welders from age group of 20 years and above, having welding work experience of more than one year, were included in the study. The sampling strategy was non-random convenient sampling. A pretested structured questionnaire was used to collect data. Topical ocular anesthetic use among welders was found to be 45.6%. Statistically significant association was found between knowledge and practices of welders regarding their safety measures (p<0.05). On binary logistic regression, work experience was found to be the strongest predictor of good knowledge (OR = 4.15, 95% CI = 1.45 - 12.15) and practices (OR=10.46 95% CI = 2.92 - 37.51). Key Words: Welder, Topical anesthetic abuse, Knowledge, Practices, Perceptions.


Assuntos
Doenças Profissionais , Exposição Ocupacional , Soldagem , Adulto , Anestésicos Locais , Estudos Transversais , Humanos , Ferreiros , Doenças Profissionais/epidemiologia , Paquistão , Adulto Jovem
9.
Front Public Health ; 9: 660451, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34095065

RESUMO

Background: Musculoskeletal disorders in welders may influence their health-related quality of life. However, few studies have addressed this issue and their results were inconclusive. This study investigates whether there are musculoskeletal disorders with a higher incidence in welders compared to non-welders, and whether these disorders lead to an increase in bodily pain which in turn decreases their health-related quality of life. Methods: A priori analyses of statistical power were conducted to determine the sample size needed to find medium to large statistical effects, for a 0.05 alpha, and critical sampling, combined with snowball sampling, was carried out. The study was cross-sectional, and participants were asked to respond to a survey using validated instruments (N welders = 40, N non-welders = 42). Results: As expected, a higher incidence of symptoms of musculoskeletal disorders in the cervical, dorsal, lumbar, and wrists and hands was found in welders in comparison to non-welders. Furthermore, the presence of musculoskeletal disorders, particularly in the lumbar area, was related to an increased bodily pain and decreased health-related quality of life. Conclusion: Welders are exposed to a higher incidence of musculoskeletal disorders that decrease their quality of life. It is essential to increase the awareness of welders, organizations, and regulatory institutions toward this issue in order to motivate the development and implementation of prevention strategies. The need for primary and secondary prevention-type strategies, which have already proven their effectiveness in the context of welding, is highlighted.


Assuntos
Doenças Musculoesqueléticas , Soldagem , Estudos Transversais , Humanos , Ferreiros , Doenças Musculoesqueléticas/epidemiologia , Dor , Portugal/epidemiologia , Qualidade de Vida
10.
J Orthod ; 48(2): 127-134, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-34160324

RESUMO

OBJECTIVE: To compare the mechanical strength of joints made by conventional soldering with those made by alternative, more biocompatible, methods (spot, tungsten inert gas [TIG] and laser welding), and to compare the microstructural morphology of wires welded with these techniques. DESIGN: In vitro, laboratory study. METHODS: Forty stainless-steel wire segments with 0.8-mm diameter were joined by silver soldering, spot, laser and TIG welding. Ten specimens were produced for each one. Tensile strength test was performed 24 h after welding on the Emic DL2000™ universal testing machine, using a load cell of 1000 N with a crosshead speed of 10 mm/min. RESULTS: The highest tensile strength mean values were obtained with silver soldering (532 N), next were laser (420 N), spot (301 N) and TIG (296 N) welding. Statistically significant differences were observed between the groups; the Dunn post-hoc test revealed differences between laser and spot welding (p=0.046), laser and TIG (p = 0.016), spot and silver (p <0.001), and silver and TIG (p <0.001). CONCLUSION: Laser welding strength is high, and comparable to silver welding. Spot and TIG techniques present comparable and significantly lower strengths. The four methods presented resistance values compatible with orthodontic use. The microstructural morphology is different for each technique. The association between the mechanical performance and the microstructure evaluation shows that laser presented the highest quality joint.


Assuntos
Soldagem em Odontologia , Soldagem , Humanos , Teste de Materiais , Aço Inoxidável , Resistência à Tração , Tungstênio
11.
Work ; 69(3): 885-894, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34180459

RESUMO

BACKGROUND: Welding is one of the most hazardous professions across the globe. Several risk factors are associated with Indian unorganized welding units such as welding gases, fumes and dust particles resulting in various respiratory health problems. OBJECTIVE: The objective of the present study is to examine the prevalence of respiratory symptoms, their associated factors and lung function impairment amongst the welders of the unorganized sector in India. METHODS: A cross-sectional study was conducted across 283 welders of age group 18-55 years from Punjab, India who responded to the interviewer-administrated respiratory symptoms questionnaire. Also, the lung function parameters of 50 male welders (exposed group) and 50 male non-welders (control group) working in the same environment were evaluated. RESULTS: The prevalence of respiratory symptoms such as chronic cough (38.86%), phlegm (38.86%), shortness of breath (33.56%), wheezing (32.15%), chest tightness (36.40%,) and sputum (34.27%) was reported by the welders. The observed mean values of forced vital capacity (FVC), forced expiratory volume in 1s (FEV1) and FEV1/FVC ratio of welders were (3.37±0.175), (2.59±0.16) and (76.63±6.16) respectively and that of non-welders were (3.70±0.15), (3.05±0.25) and (82.49±7.62) respectively. CONCLUSIONS: The welders were found to be at significant risk of developing pulmonary diseases. Long working hours, low level of education, hazardous working conditions, lack of implementation of safety laws make welders more vulnerable to health risks. The welders of Indian unorganized sector work without any technical training related to welding and safety. Proper orientation sessions about the workplace hazards and to maintain hygiene at their workplace should be organized. Welders must be provided with Personal Protective Equipment (PPE). Welders should take proper health check-up and medication to sustain healthiness.


Assuntos
Doenças Profissionais , Exposição Ocupacional , Soldagem , Adolescente , Adulto , Estudos Transversais , Humanos , Índia/epidemiologia , Masculino , Ferreiros , Pessoa de Meia-Idade , Doenças Profissionais/epidemiologia , Doenças Profissionais/etiologia , Exposição Ocupacional/efeitos adversos , Local de Trabalho , Adulto Jovem
12.
Artigo em Chinês | MEDLINE | ID: mdl-34074087

RESUMO

Objective: To assess the health risks of welding fume jobs with five occupational health risk assessment methods, and to compare the advantages, disadvantages and applicability of these methods in the health risk assessment of welding fume. Methods: The International Commission for Mining and Metals (ICMM) occupational health risk assessment method, MES method, the qualitative method and comprehensive index method in GBZ/T 298-2017 "Technical Guidelines for Occupational Health Risk Assessment of Chemical Hazardous Factors in the Workplace" were used to assess the risk of welding fume exposure positions in four manufacturing enterprises in Tianjin in March, 2020. The assessment results of different methods were standardized by risk ratio (RR) . Results: After the results were standardized, the results of enterprises 1, 2 and 4 were negligible risks, enterprise 3 was medium risk in the ICMM matrix method and MES method, and the results of ICMM quantitative method for each enterprise were negligible risk, low risk, extremely high risk and low risk, respectively. The results of the qualitative assessment of the guidelines for all companies were negligible risks, and the comprehensive index method were medium risks. Conclusion: The five models are all suitable for occupational health risk assessment of welding fumes, but they all have certain shortcomings. They should be combined with qualitative and semi-quantitative assessment results for comprehensive analysis.


Assuntos
Poluentes Ocupacionais do Ar , Exposição Ocupacional , Saúde do Trabalhador , Soldagem , Poluentes Ocupacionais do Ar/análise , Gases , Humanos , Exposição Ocupacional/análise , Medição de Risco , Local de Trabalho
13.
J Occup Environ Med ; 63(6): 490-502, 2021 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-34048382

RESUMO

INTRODUCTION: Welding fume exposure of welders occurs either directly from the welding process and sputters or from the fume background within the workshop. In this study the contribution of fume originating directly from the welding process was assessed. METHODS: Exposure was quantified by measuring the time integral of fume mass concentration using a tapered element oscillating micro balance connected to a welder dummy. RESULTS: Direct fume exposure was highest for welding processes with low fume emission rates and lowest for processes with high fume emission rates. CONCLUSIONS: This finding is supposed to be due to the higher energy input of high emitting processes which stabilizes the thermic column and therefore eliminates fume particles from the welder's breathing zone. Exposure can be minimized by additionally optimizing workshop ventilation.


Assuntos
Poluentes Ocupacionais do Ar , Exposição Ocupacional , Soldagem , Poluentes Ocupacionais do Ar/análise , Gases , Humanos , Exposição por Inalação/efeitos adversos , Exposição por Inalação/análise , Pulmão/química , Ferreiros , Exposição Ocupacional/efeitos adversos , Exposição Ocupacional/análise
14.
Ann Work Expo Health ; 65(7): 775-788, 2021 08 05.
Artigo em Inglês | MEDLINE | ID: mdl-33889935

RESUMO

Welding fumes vary in composition depending on the materials and processes used, and while health outcomes in full-time welders have been widely studied, limited research on apprentices exists. Besides, few data are available for metals such as vanadium and antimony. This study aimed to look at individual metals present in welding fumes in the learning environment of apprentice welders. Forty-three welders and 41 controls were chosen from trade programmes at the Northern Alberta Institute of Technology. Ambient and personal air samples were collected at days 0, 1, 7, and 50 of their training and analysed for mass and metal concentrations using Inductively Coupled Plasma Mass Spectrometry. Results showed increases in particle and metal concentrations as apprentices progressed throughout their education and that concentrations at day 50 were similar to levels found in the literature for professional welders. Variable concentrations indicate that some individuals may not properly use the local exhaust ventilation system. Other possible explanation for variations are the position of the sampler on the shoulder, the time spent welding and in each welding position, and the skills of the welders. Strong relationships were observed between particle and metal concentrations, suggesting that these relationships could be used to estimate metal exposure in welders from particle exposure. Welding processes were the most important determinant of exposure in apprentice welders, with Metal Core Arc Welding producing the largest particle concentrations followed by oxyacetylene cutting, and Gas Metal Arc Welding. Health risk assessment showed that welder apprentices are at risk for overexposure to manganese, which suggests that professional welders should be monitored for manganese as they are exposed more than apprentices. Training in proper positioning of local exhaust ventilation system and proper use of respirators are recommended in training facilities.


Assuntos
Poluentes Ocupacionais do Ar , Exposição Ocupacional , Soldagem , Poluentes Ocupacionais do Ar/análise , Humanos , Exposição por Inalação/análise , Ferreiros , Exposição Ocupacional/análise , Medição de Risco
15.
Biomacromolecules ; 22(5): 1867-1874, 2021 05 10.
Artigo em Inglês | MEDLINE | ID: mdl-33881832

RESUMO

Three-dimensional (3D) microfibrous scaffolds hold great promise for biomedical applications due to their good mechanical properties and biomimetic structure similar to that of the fibrous natural extracellular matrix. However, the large diameter and smooth surface of microfibers provide limited cues for regulating cell activity and behaviors. In this work, we report a facile heat-welding-and-embossing strategy to develop 3D macroporous microfibrous scaffolds with a featured surface topography. Here, solid monosodium glutamate (MSG) particles with crystalline ridge-like surface features play a key role as templates in both the formation of scaffold pores and the surface embossing of scaffold fibers when short thermoplastic polypropylene microfibers were heat-welded. The embossing process can be programmed by adjusting heating temperatures and MSG/fiber ratios. Compared to traditional 3D microfibrous scaffolds, the as-welded 3D scaffolds show higher compressive strength and modulus. Taking mouse C2C12 myoblasts as a model cell line, the scaffolds with embossed surface features significantly promoted the growth of cells, interactions of cells and scaffolds, and formation of myotubes. The findings indicate that the as-prepared 3D scaffolds are a good platform for cell culture study. The facile strategy can be applied to fabricate different fibrous scaffolds by changing the combination of templates and thermoplastic polymer fibers with a melting temperature lower than that of the template. The obtained insights in this work could provide a guide and inspiration for the design and fabrication of functional 3D fibrous scaffolds.


Assuntos
Tecidos Suporte , Soldagem , Animais , Matriz Extracelular , Temperatura Alta , Camundongos , Engenharia Tecidual
16.
Liver Int ; 41(7): 1600-1607, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-33713383

RESUMO

BACKGROUND & AIMS: Inhalation of welding fume may cause pulmonary disease known as welder's lung. At our centre we came across a number of welders with systemic iron overload and prolonged occupational history and we aimed at characterizing this novel clinical form of iron overload. METHODS: After exclusion of other known causes of iron overload, 20 welders were fully evaluated for working history, hepatic, metabolic and iron status. MRI iron assessment was performed in 19 patients and liver biopsy in 12. We included 40 HFE-HH patients and 24 healthy controls for comparison. RESULTS: 75% of patients showed lung HRCT alterations; 90% had s-FERR > 1000 ng/mL and 60% had TSAT > 45%. Liver iron overload was mild in 8 and moderate-severe in 12. The median iron removed was 7.8 g. Welders showed significantly lower TSAT and higher SIS and SIS/TIS ratio than HFE-HH patients. Serum hepcidin was significantly higher in welders than in HFE-HH patients and healthy controls. At liver biopsy, 50% showed liver fibrosis that was mild in four, and moderate-severe in two. Liver staging correlated with liver iron overload. CONCLUSIONS: Welders with prolonged fume exposure can develop severe liver iron overload. The mechanism of liver iron accumulation is quite different to that of HFE-HH suggesting that reticuloendothelial cells may be the initial site of deposition. We recommend routine measurement of serum iron indices in welders to provide adequate diagnosis and therapy, and the inclusion of prolonged welding fume exposure in the list of acquired causes of hyperferritinemia and iron overload.


Assuntos
Sobrecarga de Ferro , Soldagem , Humanos , Ferro , Fígado , Pulmão/diagnóstico por imagem
17.
Ecotoxicol Environ Saf ; 215: 112144, 2021 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-33743405

RESUMO

Particulate matter with an aerodynamic diameter of ≤ 2.5 µm (PM2.5) has been linked to adverse health outcomes in welding workers. The objective of this study was to investigate associations of chronic exposure to metal fume PM2.5 in shipyard workers with health outcomes. A longitudinal study was conducted to determine the effects of metal fume PM2.5 on FeNO, urinary metals, urinary oxidative stress, inflammation, and stress hormones in workers. There were 20 office workers and 49 welding workers enrolled in this study who were followed-up for a second year. We observed that Fe, Zn, and Mn were abundant in PM2.5 to which welding workers were personally exposed, whereas PM2.5 to which office workers were personally exposed was dominated by Pb, Cu, and Zn. We observed in the first and/or second visits that urinary 8-iso-prostaglandin F2-α (PGF2α) and 8-hydroxy-2'-deoxy guanosine (8-OHdG) were significantly increased by exposure. An increase in urinary interleukin (IL)-6 and decreases in urinary serotonin and cortisol were observed in the first and/or second visits after exposure. PM2.5 was associated with decreases in urinary 8-OHdG and cortisol among workers. Next, we observed that urinary Ni, Co, and Fe had significantly increased among workers after a year of exposure. Urinary metals were associated with decreases in urinary 8-iso-PGF2α and cortisol among workers. Urinary Ni, Cu, and Fe levels were associated with an increase in urinary IL-6 and a decrease in urinary cortisol among workers. In conclusion, chronic exposure to metal fume PM2.5 was associated with inflammation and a cortisol deficiency in shipyard workers, which could associate with adrenal glands dysfunction.


Assuntos
Hidrocortisona/sangue , Metais , Exposição Ocupacional/estatística & dados numéricos , Material Particulado , 8-Hidroxi-2'-Desoxiguanosina , Adulto , Gases , Humanos , Inflamação , Interleucina-6 , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Exposição Ocupacional/análise , Estresse Oxidativo , Soldagem
18.
Artigo em Chinês | MEDLINE | ID: mdl-33781036

RESUMO

Objective: To investigate the current situation of occupational hazards in automobile manufacturing enterprises in Shandong Province. Methods: From February to May 2019, the convenience sampling method was adopted to conduct on-site occupational health surveys with 20 automobile manufacturing enterprises in Shandong Province as the survey subjects, to detect the occupational hazard factors in the workplaces and individual exposure levels, and to analyze the occupational health check results of operators. Results: There were 13 small-sized, 4 medium-sized and 3 large-sized enterprises among the 20 automobile manufacturing enterprises. The detection results of benzene and toluene in the workplaces met the occupational exposure limits, and the detection results of welding fumes, manganese and its compounds, and xylene exceed the occupational exposure limits. The maximum short-term exposure concentration (C(STE)) of welding fume in the air of workplaces was 24.23 mg/m(3), and the over-standard rate was 11.0% (16/146) . The maximum time-weighted average concentration (C(TWA)) of welding fume of operators is 10.60 mg/m(3), and the over-standard rate was 11.0% (8/73) . The maximum C(STE) of manganese and its compounds in the air of workplaces was 0.879 mg/m(3), and the of manganese and its compounds of operators was 0.175 mg/m(3), and the over-standard rate was 5.7% (4/70) . The maximum xylene C(STE) in the air of workplaces was 230.00 mg/m(3), and the over-standard rate was 3.9% (2/51) . The maximum xylene C(TWA) of operators was 70.40 mg/m(3), the over-standard rate was 3.6% (1/28) . Among the 4775 workers exposed to occupational hazards, 38 (0.80%) were suspected of electric welder's pneumoconiosis, 27 (0.57%) were suspected of manganese poisoning and 31 (0.65%) were suspected of chronic low-concentration benzene and benzene series poisoning. The detection rates of suspected occupational diseases among workers in small and medium-sized enterprises were relatively high, 2.86% (30/1048) and 4.51% (51/1132) respectively. There was a statistically significant difference in the detection rates of suspected occupational diseases among the operators of different scale automobile manufacturers (P<0.05) . Conclusion: The exposure levels of electric welding fumes, manganese and its compounds in welding jobs and xylene exposure levels in spray painting jobsin Shandong Province's automobile manufacturing enterprises are more serious. The supervision and management of occupational hygiene should be strengthened, the working environment should be improved, and the health of welding and painting workers should be protected.


Assuntos
Poluentes Ocupacionais do Ar , Doenças Profissionais , Exposição Ocupacional , Pneumoconiose , Soldagem , Poluentes Ocupacionais do Ar/análise , Automóveis , Humanos , Exposição Ocupacional/análise
19.
J Hazard Mater ; 413: 125273, 2021 07 05.
Artigo em Inglês | MEDLINE | ID: mdl-33581669

RESUMO

Welding fume particles are hazardous. Their toxicity likely depends on their composition and reactivity. This study aimed at exploring the role of sodium or other fluorides (NaF), which are intentionally added to flux-cored wire electrodes for stainless steel welding, on the solubility (in phosphate buffered saline) and toxicity of the generated welding fume particles. A multi-analytical particle characterization approach along with in-vitro cell assays was undertaken. The release of Cr(VI) and Mn from the particles was tested as a function of fluoride solution concentration. The welding fume particles containing NaF released significantly higher amounts of Cr(VI) compared with solid wire reference fumes, which was associated with increased cytotoxicity and genotoxicity in-vitro. No crystalline Na or potassium (K) containing chromates were observed. Cr(VI) was incorporated in an amorphous mixed oxide. Solution-added fluorides did not increase the solubility of Cr(VI), but contributed to a reduced Mn release from both solid and flux-cored wire fume particles and the reduction of Cr(VI) release from solid wire fume particles. Chemical speciation modeling suggested that metal fluoride complexes were not formed. The presence of NaF in the welding electrodes did not have any direct, but possibly an indirect, role in the Cr(VI) solubility of welding fumes.


Assuntos
Poluentes Ocupacionais do Ar , Nanopartículas , Soldagem , Poluentes Ocupacionais do Ar/análise , Fluoretos , Nanopartículas/toxicidade , Solubilidade , Aço Inoxidável
20.
Ecotoxicol Environ Saf ; 212: 111935, 2021 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-33578128

RESUMO

During the welding activities many compounds are released, several of these cause oxidative stress and inflammation and some are considered carcinogenic, in fact the International Agency for Research on Cancer established that welding fumes are carcinogenic to humans. The aim of the present study was to analyze the cytotoxic and genotoxic potential of exposure to welding fumes and to determine concentrations of metals in blood and urine of occupationally exposed workers. We included 98 welders and 100 non-exposed individuals. Our results show significant increase in the frequency of micronuclei (MN), nucleoplasmic bridges (NPB), nuclear buds (NBUD) and necrotic cells (NECR) in cytokinesis-block micronucleus cytome (CBMN-Cyt) assay, as well as in the telomere length (TL) of the exposed individuals with respect to the non-exposed group. In the analysis of the concentrations of inorganic elements using PIXE method, were found higher concentrations of Cr, Fe and Cu in the urine, and Cr, Fe, Mg, Al, S, and Mn in the blood in the exposed group compared to the non-exposed group. A significant correlation was observed between MN and age and between NPB and years of exposure. Additionally, we found a significant correlation for TL in relation to MN, NPB, age and years of exposure in the exposed group. Interestingly, a significant correlation between MN and the increase in the concentration of Mg, S, Fe and Cu in blood samples of the exposed group, and between MN and Cr, Fe, Ni and Cu in urine. Thus, our findings may be associated with oxidative and inflammatory damage processes generated by the components contained in welding fumes, suggesting a high occupational risk in welding workers.


Assuntos
Poluentes Ocupacionais do Ar/análise , Bioensaio , Testes para Micronúcleos/métodos , Exposição Ocupacional/análise , Telômero , Biomarcadores/análise , Citocinese , Dano ao DNA , Humanos , Linfócitos , Estresse Oxidativo , Soldagem
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