Current status and research progress of occupational health monitoring in welding fume operations / 中华劳动卫生职业病杂志

Welding operations are widely present in the manufacturing production process, involving a large number of occupational groups, and are the key occupations where work injuries and occupational diseases occur in China. For different welding processes and welding materials, the content and focus of occupational health monitoring are different. At present, the item of occupational health examination in welding operation is in poor consistency with the on-site exposure of occupational hazard factors, and it is mainly concentrated in the stage of disease development, which can not reflect the early health damage caused by welding dust exposure in time. The emergence of biomarkers of welding dust can make up for this defect. Therefore, it is of great significance to describe the current situation of occupational health monitoring of welding dust and summarize the research progress of related biomarkers for the early prevention of diseases caused by welding dust and the practice of occupational health monitoring.

Investigation and analysis of occupational hazards in construction of power transmission and transformation project / 中华劳动卫生职业病杂志

Objective: To investigate the occupational hazard factors and exposure levels of workers during the construction of power transmission and transformation projects. Methods: Analysis and identification of occupational hazard factors were carried out for typical construction process of 6 power transmission projects and 3 substation projects in September 2018. The on-site occupational health investigation was carried out to detect and analyze the exposure levels of workers to occupational hazard factors. Results: The time weighted average concentration (C(TWA)) of crushing workers exposed to silica dust and welders exposed to welding fume in substation projects were 2.72 and 14.03 mg/m(3), respectively. The 8 h equivalent sound level results of exposure noise of carpenters in power transmission projects and crushing workers, reinforcement workers, carpenters, scaffolders, road builders in substation projects were 87.9, 92.5, 87.1, 92.5, 93.0 and 90.2 dB (A) , respectively. The 4-hour time equal energy frequency weighted vibration acceleration of hand-transmitted vibration of bricklayer in power transmission projects, bricklayer, general worker 3, road builder 1 and road builder 2 of substation projects were 5.36, 5.21, 5.28, 10.71 and 5.22 m/s(2), respectively. The effective irradiance of electric welding arc light of welders' limbs in power transmission projects and substation projects were 401.19, 319.68 μW/cm(2), respectively. All of the above exceeded the requirements of occupational exposure limits. The occupational radiation levels and exposure limits of hazardous chemical factors met the requirements of each post. Conclusion: During the construction of power transmission and transformation projects, the exposure levels of occupational hazard factors in multiple posts exceed the standard. The main responsibility of employers for occupational disease prevention and control should be implemented, and targeted comprehensive measures should be taken to reduce the exposure levels of occupational hazard factors of workers.

Comparative analysis on occupational hazards of three welding operations / 中华劳动卫生职业病杂志

Objective: To explore the occupational hazards caused by three kinds of welding operations, and to provide data support for individual protection. Methods: In October 2020, the welding fumes, metal elements and welding arc generated by three welding operations of argon gas shielded welding (JS80 welding wire) , manual welding (ZS60A welding rod) and carbon dioxide shielded welding (907A flux cored wire) were collected and measured in the welding laboratory. The samples were analyze and compare in the laboratory, and the differences of the occupational hazard factors of the three welding operations were judged. Results: The concentration of welding fume produced by carbon dioxide shielded welding, manual welding (ZS60A electrode) , and argon gas shielded welding (JS80 welding wires) were 6.80 mg/m(3), 6.17 mg/m(3), and 3.13 mg/m(3), respectively. The effective irradiance of the welding arc outside the welding mask from high to low is manual welding (ZS60A electrode) , carbon dioxide shielded welding (907A flux-cored welding wire) , and argon shielded welding (JS80 welding wire) , respectively 1 010.7, 740.9, 589.5 μW/cm(2). The long-wave ultraviolet UVA intensity generated by argon shielded welding (JS80 welding wire) is the largest, which is 1 500 μW/cm(2). The content of Mn in the three welding operations is the highest, and JS80 welding wire has the highest Mn content of 128493.2 mg/kg. 907A flux cored wire has the highest Ti content, which is 24355.5mg/kg. The electrode ZS60A has the highest Cu content, which is 24422.12 mg/kg. Conclusion: The intensity of occupational hazards is different in the three kinds of welding operations, so the methods of personal protective equipment, field exposure assessment and health monitoring should be more targeted.

Biomonitoring of Metal Exposure During Additive Manufacturing (3D Printing)

BACKGROUND: Additive manufacturing (AM) is a rapidly expanding new technology involving challenges to occupational health. Here, metal exposure in an AM facility with large-scale metallic component production was investigated during two consecutive years with preventive actions in between.METHODS: Gravimetric analyzes measured airborne particle concentrations, and filters were analyzed for metal content. In addition, concentrations of airborne particles <300 nm were investigated. Particles from recycled powder were characterized. Biomonitoring of urine and dermal contamination among AM operators, office personnel, and welders was performed.RESULTS: Total and inhalable dust levels were almost all below occupational exposure limits, but inductively coupled plasma mass spectrometry showed that AM operators had a significant increase in cobalt exposure compared with welders. Airborne particle concentrations (<300 nm) showed transient peaks in the AM facility but were lower than those of the welding facility. Particle characterization of recycled powder showed fragmentation and condensates enriched in volatile metals. Biomonitoring showed a nonsignificant increase in the level of metals in urine in AM operators. Dermal cobalt and a trend for increasing urine metals during Workweek Year 1, but not in Year 2, indicated reduced exposure after preventive actions.CONCLUSION: Gravimetric analyses showed low total and inhalable dust exposure in AM operators. However, transient emission of smaller particles constitutes exposure risks. Preventive actions implemented by the company reduced the workers' metal exposure despite unchanged emissions of particles, indicating a need for careful design and regulation of the AM environments. It also emphasizes the need for relevant exposure markers and biomonitoring of health risks.

Welding strength of NiTi wires

ABSTRACT Objective: To identify the appropriate power level for electric welding of three commercial brands of nickel-titanium (NiTi) wires. Methods: Ninety pairs of 0.018-in and 0.017 × 0.025-in NiTi wires were divided into three groups according to their manufacturers - GI (Orthometric, Marília, Brazil), GII (3M OralCare, St. Paul, CA) and GIII (GAC,York, PA) - and welded by electrical resistance. Each group was divided into subgroups of 5 pairs of wires, in which welding was done with different power levels. In GI and GII, power levels of 2.5, 3, 3.5, 4, 4.5 and 5 were used, while in GIII 2.5, 3, 3.5 and 4 were used (each unit of power of the welding machine representing 500W). The pairs of welded wires underwent a tensile strength test on an universal testing machine until rupture and the maximum forces were recorded. Analysis of variance (ANOVA) and post-hoc tests were conducted to determine which subgroup within each brand group had the greatest resistance to rupture. Results: The 2.5 power exhibited the lowest resistance to rupture in all groups (43.75N for GI, 28.41N for GII and 47.57N for GIII) while the 4.0 power provided the highest resistance in GI and GII (97.90N and 99.61N, respectively), while in GIII (79.28N) the highest resistance was achieved with a 3.5 power welding. Conclusions: The most appropriate power for welding varied for each brand, being 4.0 for Orthometric and 3M, and 3.5 for GAC NiTi wires.

RESUMO Objetivo: identificar a potência mais adequada para solda elétrica em três marcas comerciais de fios de níquel-titânio (NiTi). Métodos: noventa pares de fios ortodônticos de NiTi, de dimensões 0,018" e 0,017" × 0,025'', foram soldados por resistência elétrica e distribuídos em três grupos: GI (Orthometric, Marília, São Paulo, Brasil), GII (3M, São José do Rio Preto, São Paulo, Brasil) e GIII (GAC, Yorque, Pensilvânia, Estados Unidos). Cada grupo foi dividido em subgrupos de cinco pares de fios soldados com diferentes níveis de potência. Nos GI e GII, os fios foram soldados com níveis de potência de 2.5, 3, 3.5, 4, 4.5 e 5; enquanto no GIII as potências utilizadas foram de 2.5, 3, 3.5 e 4. Os pares de fios foram submetidos a um teste de tração até sua ruptura, com registro das forças máximas. Análises de variância (ANOVA) e testes post-hoc foram realizados para determinar qual subgrupo, dentro de cada grupo, obteve a maior força de resistência. Resultados: a potência 2.5 exibiu a menor resistência à ruptura para todos os grupos (43,75 N para o GI; 28,41 N para o GII e 47,57 N para o GIII). A potência 4 mostrou maior resistência à ruptura nos GI e GII (97,90 N e 99,61 N, respectivamente), enquanto no GIII (79,28 N) foi a potência 3.5. Conclusões: os níveis de potência mais adequados variaram para as marcas comerciais, sendo identificados como 4 para Orthometric e 3M, e 3.5 para GAC.

Late Onset Disassembly of a Modular Neck-stem Component after Cementless Hip Replacement without Dislocation: A Case Report and Review of Literatures / 대한고관절학회지

Modular femoral prostheses are characterized by a second neck-stem junction. This modularity provides many clinical benefits including hip offset restoration, intraoperative leg length and anteversion adjustment. Although, this extra junction in modular femoral prostheses can contribute to catastrophic consequences like fracture, cold welding, corrosion and fretting of the modularity. However, only few complications related to the modularity itself have been reported in the literature. We report a unique case of neck-stem component dissociation without dislocation of the R-120PC™ Modular Stem (DJO Surgical). Our 71-year-old obese female patient underwent cementless hip replacement 5 years ago. Following radiographic confirmation of neck-stem dissociation open reduction was performed and wiring fixation was applied to secure the neck to the stem. After reduction and fixation, hip joint was stable, and our patient returned to her daily routine 2.5 months postoperatively. The last follow up was at 12 months after surgery with excellent radiographic and clinical evaluation.

Avaliação da resistência flexural em diferentes métodos de soldagem / Evaluation of flexural resistance in different welding methods

O objetivo do presente estudo foi avaliar três diferentes tipos de soldagem: Chama Direta a maçarico (convencional\brasagem), Solda Mista representada por fixação de dois pontos (Solda Elétrica Fixator - Kernit, Brasil), e completada com solda convencional, e o método de Solda a Laser (Soldadora Desktop - Sisma LM 500, Itália). Dois implantes plataforma Bränemark 4.1 mm (Neodent, Curitiba/Brasil) foram fixados em uma matriz de alumínio para simular uma ponte fixa implanto-suportada de três elementos. Os espécimes foram obtidos a partir de um bloco de cera CAD-CAM (Ceramill-Amammgirrbarch). Trinta e duas UCLAs hexágono externo foram fresadas e posteriormente unidas a uma barra pré-fabricada em cera com 2,5mm. Os corpos de prova foram fundidos em liga de cobalto-cromo simulando uma prótese fixa de três elementos. Esses espécimes foram divididos aleatoriamente e separados em três grupos (n=6): grupo A (solda chama direta), grupo B (solda mista), grupo C (solda laser). Os espécimes foram seccionados ao meio e unidos com resina acrílica para simular uma soldagem em prótese fixa. Os corpos foram soldados e tratados de acordo com a proposição. Após a soldagem os corpos de prova foram usinados e levados ao teste de flexão na técnica de três pontos. Os dados foram submetidos aos testes estatísticos de Tukey. Os cálculos estatísticos foram conduzidos adotando-se o nível de significância de 5% (α = 0,05). Houve diferença estatisticamente significativa entre os grupos soldados. Os resultados demonstraram valores mais elevados nos grupos A e B, solda convencional e solda mista, e menor valor no grupo C, solda a laser. No entanto, considerando a metodologia aplicada, a solda a laser mostrou uma menor resistência flexural comparada à soldagem convencional e mista, e a fixação prévia de solda elétrica com complemento de solda convencional (solda mista) não alterou a resistência flexural, produzindo resultado semelhante à solda convencional

The objective of this study was to evaluate three different types of welding, blowtorch; (conventional/brazing), welder Joint; represented by securing two points (Arc Welding Fixator - Kernit, Brazil), and supplemented with conventional welding), and Laser welding method (welder Desktop - Sisma LM 500, Italy). Two implants Bränemark 4.1 mm platform (Neodent, Curitiba/Brazil) were fixed in an aluminum matrix. Specimens were obtained from a CAD-CAM wax block (Ceramill - Amammgirrbarch) were milled 32 UCLAs (external hexagon, Bränemark platform), and subsequently joined to a prefabricated bar also wax 2.5 mm, the specimens were casted in cobalt-chromium alloy. These specimens were randomly divided and separated into 3 groups: group A (welding direct flame), Group B (mixed welding), C (laser welding), with 6 samples for each group. The specimens of each group were cut in half to simulate a fixed prosthesis in welding, and put together with acrylic resin. The bodies were welded and treated according to the statement. After the specimens were welded, they were manually grinded and submitted to the 3 points bending test technique. Data were subjected to statistical tests of Tukey. Statistical calculations were performed adopting the significance level of 5% (α = 0.05), using SPSS 20 (SPSS Inc., Chicago, IL, USA). There were differences between the soldered groups. The data showed the highest values obtained in groups A and B, conventional welding and soldering joint, and lower in group C, the laser welding. However, within the applied methodology, the laser welding showed a lower flexural strength compared to conventional and mixed welding, and that the advance fixing of electric welding, conventional welding complement (mixed welding), does not change its flexural strength, producing results similar to conventional welding

Cancer Risks among Welders and Occasional Welders in a National Population-Based Cohort Study: Canadian Census Health and Environmental Cohort

BACKGROUND: Welders are exposed to many known and suspected carcinogens. An excess lung cancer risk among welders is well established, but whether this is attributable to welding fumes is unclear. Excess risks of other cancers have been suggested, but not established. We investigated welding cancer risks in the population-based Canadian Census Health and Environmental Cohort. METHODS: Among 1.1 million male workers, 12,845 welders were identified using Standard Occupational Classification codes and followed through retrospective linkage of 1991 Canadian Long Form Census and Canadian Cancer Registry (1992–2010) records. Hazard ratios (HRs) were calculated using Cox proportional hazards models based on estimated risks of lung cancer, mesothelioma, and nasal, brain, stomach, kidney, and bladder cancers, and ocular melanoma. Lung cancer histological subtypes and risks by industry group and for occasional welders were examined. Some analyses restricted comparisons to blue-collar workers to minimize effects of potential confounders. RESULTS: Among welders, elevated risks were observed for lung cancer [HR: 1.16, 95% confidence interval (CI): 1.03–1.31], mesothelioma (HR: 1.78, 95% CI: 1.01–3.18), bladder cancer (HR: 1.40, 95% CI: 1.15–1.70), and kidney cancer (HR: 1.30, 95% CI: 1.01–1.67). When restricted to blue-collar workers, lung cancer and mesothelioma risks were attenuated, while bladder and kidney cancer risks increased. CONCLUSION: Excess risks of lung cancer and mesothelioma may be partly attributable to factors including smoking and asbestos. Welding-specific exposures may increase bladder and kidney cancer risks, and particular sources of exposure should be investigated. Studies that are able to disentangle welding effects from smoking and asbestos exposure are needed.

Estudio exploratorio II: identificación de nanopartículas en procesos industriales de soldadura y de minería / Exploratory study II: identification of nanoparticles in industrial processes welding and mining

Se realizó un estudio exploratorio sobre la exposición laboral a nanopartículas en procesos de empresas del sector minero, fundición y soldadura. Para evaluar la exposición se utilizó un método cualitativo simplificado y un método semi-cuantitativo basado en las técnicas tradicionales de higiene ocupacional y de espectroscopía y microscopía electrónica para caracterizar las nanopartículas en cuanto a composición elemental, morfología y tamaños. Se evaluó cualitativamente el riesgo de exposición a nanopartículas de sílice y hierro, encontrándose una mayor criticidad en los procesos de preparación de muestras de minerales y de vaciado de colada en moldes de fundición. El análisis de muestras personales y ambientales evidenció la exposición de trabajadores a nanopartículas de sílice, hierro, magnesio, aluminio, manganeso, entre otras. La toxicidad de estas depende de la morfología y vía de ingreso (la principal vía es por inhalación). Se identificaron morfologías esféricas e irregulares, así como nanoalambres, aglomerados, estructuras cristalinas y amorfas, con tamaños bajo 100 nm. El trabajo realizado entrega la composición elemental y morfológica de las nanopartículas a los cuales se exponen los trabajadores en los procesos evaluados, junto con el alcance de los métodos de evaluación y la necesidad futura de realizar estudios cuantitativos para determinar niveles de exposición y concentraciones.

An exploratory study on occupational exposure to nanoparticles in processes of mining companies, casting and welding was performed. To assess exposure it was used a simplified qualitative and semiquantitative method based on traditional techniques of occupational hygiene and spectroscopy and electron microscopy to characterize nanoparticles in terms of elemental composition, morphology and size. The risk of exposure to silica nanoparticles and iron was qualitatively assessed, finding a bigger criticality in the process of sample preparation and emptying mineral casting molds. Analysis of personal and environmental samples showed workers exposure to nanoparticles of silica, iron, magnesium, aluminum, manganese, among others. The toxicity of these depends on the morphology and route of entry (the main way is by inhalation). Spherical and irregular morphologies were identified, as well as nanowires, crystalline and amorphous structures with sizes below 100 nm. The work performed gives the elemental composition and morphology of nanoparticles to which workers are exposed in the processes evaluated, along with the scope of the evaluation methods and the future need for quantitative studies to determine exposure levels and concentrations.

Characterization of Total and Size-Fractionated Manganese Exposure by Work Area in a Shipbuilding Yard

BACKGROUND: Shipbuilding involves intensive welding activities, and welders are exposed to a variety of metal fumes, including manganese, that may be associated with neurological impairments. This study aimed to characterize total and size-fractionated manganese exposure resulting from welding operations in shipbuilding work areas. METHODS: In this study, we characterized manganese-containing particulates with an emphasis on total mass (n = 86, closed-face 37-mm cassette samplers) and particle size-selective mass concentrations (n = 86, 8-stage cascade impactor samplers), particle size distributions, and a comparison of exposure levels determined using personal cassette and impactor samplers. RESULTS: Our results suggest that 67.4% of all samples were above the current American Conference of Governmental Industrial Hygienists manganese threshold limit value of 100 μg/m3 as inhalable mass. Furthermore, most of the particles containing manganese in the welding process were of the size of respirable particulates, and 90.7% of all samples exceeded the American Conference of Governmental Industrial Hygienists threshold limit value of 20 μg/m3 for respirable manganese. CONCLUSION: The concentrations measured with the two sampler types (cassette: total mass; impactor: inhalable mass) were significantly correlated (r = 0.964, p < 0.001), but the total concentration obtained using cassette samplers was lower than the inhalable concentration of impactor samplers.

Morbidity patterns among the welders of eastern Nepal: a cross-sectional study

BACKGROUND: Welding process has many hazards that the welders are exposed to resulting in numbers of health effects and diseases. Safety measures and practices among welders are important ways of preventing or reducing the health hazards associated with this occupation. We conducted this study to find out the morbidity patterns among the welders working in eastern Nepal. METHODS: A cross sectional study was conducted among 300 welders using semi structured questionnaire. Morbidity categories were classified based on symptoms experienced in past 6 months. RESULTS: All the welders learned welding by apprenticeship, without any formal health and safety training. Injury was the most common problem at work followed by skin problems and eye symptoms. Age of the welders, duration of employment & welding hours per day were associated with the morbidities among the welders. CONCLUSIONS: There is a need for occupational health services for welders in Nepal. While further research may be required to make policy recommendations, the current study provides a baseline morbidity burden among these welders to look for interventions to promote health and safety at work for this neglected group of workers in Nepal.

Identificação de queimaduras térmicas como injúria relacionada ao trabalho de soldadores / Identification of thermal burns as work-related injury in welders

Objetivo Avaliar a identificação de queimaduras em soldadores como injúria relacionada ao trabalho, antes e depois da ação clínica comunicativa de Enfermagem. Métodos Estudo transversal com 161 soldadores em processo de formação. Utilizou-se modelo de julgamento e decisão clínica, adaptado na perspectiva da Enfermagem em saúde pública. Para a coleta de dados, foi aplicado questionário antes e depois da ação clínica comunicativa de Enfermagem. Resultados Para os soldadores que não referiram queimaduras durante atividade de solda, houve diferença estatística significativa (p=0,02) para a variável queimadura por fagulha nos olhos. Conclusão A ação clínica comunicativa pode modificar o conhecimento de indivíduos sobre a ocorrência de queimaduras como injúria relacionada ao trabalho...

Objective Assess identification of burns in welders as work-related injury before and after communicative clinical action. Methods Cross-sectional study conducted with 161 welders in the formation process. A model of clinic judgment and decision was used and adapted to the public health nursing. For data collection, a questionnaire was administered before and after communicative clinical action. Results For welders who did not report burns during the welding activity, a statistically significant difference (p=0.02) was observed in relation to the spark-caused eye burn variable. Conclusion Communicative clinical actions can modify individuals’ knowledge about occurrence of burns as [being] work-related injuries...

Occupational Injuries among Workers in a Welding Company within Mangaung Metropolitan Municipality

A questionnaire survey was conducted among 37 welders and 21 fitters (exposed group) and 30 office workers (unexposed group) employed by a welding company located in the Mangaung Metropolitan Municipality. The objective was to calculate and describe the prevalence of occupational injuries among these workers and to compare the frequencies of injuries. A total of 87 injuries were reported by workers. The most common injuries sustained were burns (n=29); cuts (n=24); eye injuries inflicted by foreign objects (n=19); electric shock (n=8); arc eyes (n=4); and bone fractures (n=3). Most occurred on the hands (n=57). More workers in the exposed group sustained injuries than in the unexposed group. It is necessary to implement safety measures in order to reduce the prevalence of injuries

Occupational Injuries among Workers in a Welding Company within Mangaung Metropolitan Municipality

A questionnaire survey was conducted among 37 welders and 21 fitters (exposed group) and 30 office workers (unexposed group) employed by a welding company located in the Mangaung Metropolitan Municipality. The objective was to calculate and describe the prevalence of occupational injuries among these workers and to compare the frequencies of injuries. A total of 87 injuries were reported by workers. The most common injuries sustained were burns (n=29); cuts (n=24); eye injuries inflicted by foreign objects (n=19); electric shock (n=8); arc eyes (n=4); and bone fractures (n=3). Most occurred on the hands (n=57). More workers in the exposed group sustained injuries than in the unexposed group. It is necessary to implement safety measures in order to reduce the prevalence of injuries

Expression of heat shock protein 70 and its mRNA in career exposure to manganese / 中华预防医学杂志

<p><b>OBJECTIVE</b>To analyze the expression levels of heat shock protein70 (HSPs70) and HSPs70 mRNA in different exposure to manganese, and research the neuroprotective effect on the career exposure to manganese.</p><p><b>METHODS</b>From 2008 to 2009, with cross-sectional study design, and in a locomotive and rolling stock works, by stratified random sampling method, the exposed sample consisted of 180 welders from different welding shops and 100 unexposed in the last three years, non-welder controls with age-matched workers of similar socioeconomic status from the same industry. The control workers had not been exposed to neurotoxic chemicals. The mRNA expressions of four different metabolic enzyme were detected by SYBR Green I quantitative real-time polymerase chain reaction. The expression levels of the two enzymes mRNA in different exposure to manganese were analyzed. The expressions of HSPs70 were detected by Western blot. The concentration of air manganese was determined by GFAAS. The average concentration of 8 h time (8h-TWA) was used to express the level of individual exposure to manganese, according to the air manganese workplace occupational exposure limit (8h-TWA=0.15 mg/m3), the exposed group is divided into high exposed group (>0.15 mg/m3) and low exposure group (<0.15 mg/m3).</p><p><b>RESULTS</b>The individuals exposed to manganese dose of exposed group ((0.25±0.31) mg/m3) was higher than the control group ((0.06±0.02) mg/m3) (t=6.15, P=0.001); individuals exposed to manganese dose of high exposure group for (0.42±0.34) mg/m3, which was higher than low exposure group (0.09±0.07) mg/m3 (t=9.80, P=0.001). HSPs70 mRNA and protein of exposure group (5.65±0.21, 3.26±0.15) were higher than the reference group (0.41±0.03, 1.32±0.12) (t=18.91, t=8.68, P=0.001). HSP70 mRNA and protein of high exposure group (6.48±0.37, 3.67±0.26) were higher than the low exposure group (5.15±0.23, 3.02±0.19) (t=3.24, t=2.01, P=0.003, P=0.043).</p><p><b>CONCLUSION</b>The expression of peripheral blood lymphocytes HSPs70 level and HSPs70 mRNA workers exposed to manganese increased and protect nerve cells from related to Mn stimulation induced lipid peroxidation damag.</p>

Evaluation of measurement uncertainty of welding fume in welding workplace of a shipyard / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To evaluate the measurement uncertainty of welding fume in the air of the welding workplace of a shipyard, and to provide quality assurance for measurement.</p><p><b>METHODS</b>According to GBZ/T 192.1-2007 "Determination of dust in the air of workplace-Part 1: Total dust concentration" and JJF 1059-1999 "Evaluation and expression of measurement uncertainty", the uncertainty for determination of welding fume was evaluated and the measurement results were completely described.</p><p><b>RESULTS</b>The concentration of welding fume was 3.3 mg/m(3), and the expanded uncertainty was 0.24 mg/m(3). The repeatability for determination of dust concentration introduced an uncertainty of 1.9%, the measurement using electronic balance introduced a standard uncertainty of 0.3%, and the measurement of sample quality introduced a standard uncertainty of 3.2%.</p><p><b>CONCLUSION</b>During the determination of welding fume, the standard uncertainty introduced by the measurement of sample quality is the dominant uncertainty. In the process of sampling and measurement, quality control should be focused on the collection efficiency of dust, air humidity, sample volume, and measuring instruments.</p>

Mechanical and interfacial characterization of laser welded Co-Cr alloy with different joint configurations

PURPOSE: The mechanical and interfacial characterization of laser welded Co-Cr alloy with two different joint designs. MATERIALS AND METHODS: Dumbbell cast specimens (n=30) were divided into 3 groups (R, I, K, n=10). Group R consisted of intact specimens, group I of specimens sectioned with a straight cut, and group K of specimens with a 45degrees bevel made at the one welding edge. The microstructure and the elemental distributions of alloy and welding regions were examined by an SEM/EDX analysis and then specimens were loaded in tension up to fracture. The tensile strength (TS) and elongation (epsilon) were determined and statistically compared among groups employing 1-way ANOVA, SNK multiple comparison test (alpha=.05) and Weibull analysis where Weibull modulus m and characteristic strength sigmaomicron were identified. Fractured surfaces were imaged by a SEM. RESULTS: SEM/EDX analysis showed that cast alloy consists of two phases with differences in mean atomic number contrast, while no mean atomic number was identified for welded regions. EDX analysis revealed an increased Cr and Mo content at the alloy-joint interface. All mechanical properties of group I (TS, epsilon, m and sigmaomicron) were found inferior to R while group K showed intermediated values without significant differences to R and I, apart from elongation with group R. The fractured surfaces of all groups showed extensive dendritic pattern although with a finer structure in the case of welded groups. CONCLUSION: The K shape joint configuration should be preferred over the I, as it demonstrates improved mechanical strength and survival probability.

Comparison of welder's pneumoconiosis with silicosis and follow-up study of welder's pneumoconiosis / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To study the character of welder's pneumoconiosis on CT, pathology, and lung function.</p><p><b>METHODS</b>To contrast 185 welder's pneumoconiosis and 115 silicosis on CT, pathology, and clinical characters which were diagnosed between Jan 2008 and Dec 2013. Chest X-ray and lung function of 39 welder's pneumoconiosis patients were followed up after diagnosed 4~6 years later.</p><p><b>RESULTS</b>Average age and working years of welder's pneumoconiosis were 36.7 and 11.5, less than silicosis patients 58.8 and 22.1, respectively (P<0.05). Of all 185 welder's pneumoconiosis 98.4% were of stage I and no stage III, while in silicosis group stage I, stage II and stage III were 56.5%, 22.6% and 20.9%, respectively. The ratio differences between the two groups were statistically significant,P<0.05. 82.7% of welder's pneumoconiosis patients were observed pathologically moderate or above dust deposition in lung tissue while interstitial fibrosis level was just mild (97.6% patients) or no fibrosis (2.4% patients). By contrast, 60.0% silicosis patients pathologically showed moderate or above dust deposition while 77.8% were of moderate or above fibrosis. CT findings in welder' s pneumoconiosis were diffuse branching linear structure (38.9%), low density consistent size centrilobular micronodules (19.5%), or both (30.8%). Poorly-defined ground-glass attenuation centrilobular micronodules or widely ground glass shadow were observed in 6.4% welder's pneumoconiosis patents. 30.8% patients failed to reach the original stage when 39 welder's pneumoconiosis followed up chest radiograph.</p><p><b>CONCLUSION</b>Changes in welder's lung caused by welding fume were not only siderosis, but also interstitial fibrosis.</p>

Survey of occupational health condition in a shipyard in Guangzhou, China / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To investigate the occupational health condition in a shipyard in Guangzhou, China, and to provide a basis for improving the working environment.</p><p><b>METHODS</b>The monitoring data on occupational harmful factors in the workplace and the data on health examination of the workers were analyzed, and the occupational health condition in the shipyard was evaluated with the related occupational health standards.</p><p><b>RESULTS</b>Except benzene, toluene, and electromagnetic radiation, the dust (2.02%), grinding wheel dust (3.85%), wood dust (2 out of 4 workers exceeded the standard), welding fume (16.85%), manganese dioxide (17.98%), dimethylbenzene (8.00%), and noise (53.20%) were all out of limits to different degrees. The health examination results of 2450 workers in the shipyard showed that the respiratory impairment of dust-exposed workers (3.19%) and the hearing impairment of noise-exposed workers (12.21%) were comparatively severe.</p><p><b>CONCLUSION</b>The occupational health condition in this shipyard is not good. In order to protect the workers from health hazards, it is urgent and necessary to improve the working environment and strengthen the personal protective measures.</p>

An analysis of occupational hazard in manufacturing industry in Guangzhou, China, in 2013 / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To provide data for the occupational health supervision by analyzing the occupational health status in manufacturing industry in Guangzhou, China.</p><p><b>METHODS</b>The occupational health investigation was performed in 280 enterprises randomly selected from 8 industries based on industry stratification. According to the occupational health standards, 198 out of the 280 enterprises were supervised and monitored. Sample testing was performed in 3~5 workplaces where workers were exposed to the highest concentration/intensity of occupational hazard for the longest time. Comparative analyses of the overproof rates of hazard were performed among enterprises, workplaces, and testing items from different industries.</p><p><b>RESULTS</b>The concentrations of occupational hazard in 42.93% (85/198) of enterprises and 22.96% (200/871) of workplaces were above the limit concentration. The most severe hazards were the noises in shipbuilding and wooden furniture industries and the welding fumes in shipbuilding industry. Less than 30% of enterprises were able to provide occupational health examination and periodic test reports of occupational hazard in workplaces. The rate of the workers with abnormal occupational health examination results and the need for reexamination reached 6.63% (832/12 549), and they were mostly from shipbuilding, wooden furniture, and chemical industries.</p><p><b>CONCLUSION</b>The occupational health supervision should be strengthened in enterprises, and hazard from noises and dusts should be selectively controlled or reduced. The publication of relevant data and information of occupational health in enterprises should be promoted to enhance social supervision.</p>