Physicochemical and toxicological characteristics of welding fume derived particles generated from real time welding processes.

Science.gov (United States)

Chang, Cali; Demokritou, Philip; Shafer, Martin; Christiani, David

2013-01-01

Welding fume particles have been well studied in the past; however, most studies have examined welding fumes generated from machine models rather than actual exposures. Furthermore, the link between physicochemical and toxicological properties of welding fume particles has not been well understood. This study aims to investigate the physicochemical properties of particles derived during real time welding processes generated during actual welding processes and to assess the particle size specific toxicological properties. A compact cascade impactor (Harvard CCI) was stationed within the welding booth to sample particles by size. Size fractionated particles were extracted and used for both off-line physicochemical analysis and in vitro cellular toxicological characterization. Each size fraction was analyzed for ions, elemental compositions, and mass concentration. Furthermore, real time optical particle monitors (DustTrak™, TSI Inc., Shoreview, Minn.) were used in the same welding booth to collect real time PM2.5 particle number concentration data. The sampled particles were extracted from the polyurethane foam (PUF) impaction substrates using a previously developed and validated protocol, and used in a cellular assay to assess oxidative stress. By mass, welding aerosols were found to be in coarse (PM 2.5–10), and fine (PM 0.1–2.5) size ranges. Most of the water soluble (WS) metals presented higher concentrations in the coarse size range with some exceptions such as sodium, which presented elevated concentration in the PM 0.1 size range. In vitro data showed size specific dependency, with the fine and ultrafine size ranges having the highest reactive oxygen species (ROS) activity. Additionally, this study suggests a possible correlation between welders' experience, the welding procedure and equipment used and particles generated from welding fumes. Mass concentrations and total metal and water soluble metal concentrations of welding fume particles may be

A study of the bio-accessibility of welding fumes.

Science.gov (United States)

Berlinger, Balázs; Ellingsen, Dag G; Náray, Miklós; Záray, Gyula; Thomassen, Yngvar

2008-12-01

The respiratory bio-accessibility of a substance is the fraction that is soluble in the respiratory environment and is available for absorption. In the case of respiratory exposure the amount of absorbed substance plays a main role in the biological effects. Extensive bio-accessibility studies have always been an essential requirement for a better understanding of the biological effects of different workplace aerosols, such as welding fumes. Fumes generated using three different welding techniques, manual metal arc (MMA) welding, metal inert gas (MIG) welding, and tungsten inert gas (TIG) welding were investigated in the present study. Each technique was used for stainless steel welding. Welding fumes were collected on PVC membrane filters in batches of 114 using a multiport air sampler. Three different fluids were applied for the solubility study: deionised water and two kinds of lung fluid simulants: lung epithelial lining fluid simulant (Gamble's solution) and artificial lung lining fluid simulant (Hatch's solution). In order to obtain sufficient data to study the tendencies in solubility change with time, seven different leaching periods were used (0.5, 1, 2, 4, 8, 16, 24 h), each of them with three replicates. The effect of dissolution temperature was also studied. The total amounts of selected metals in the three different welding fumes were determined after microwave-assisted digestion with the mixture of aqua regia and hydrofluoric acid. The most obvious observation yielded by the results is that the solubility of individual metals varies greatly depending on the welding technique, the composition of the leaching fluid and leaching time. This study shows that the most reasonable choice as a media for the bio-assessment of solubility might be Hatch's solution by a dissolution time of 24 h.

Characterization of Tungsten Inert Gas (TIG) Welding Fume Generated by Apprentice Welders

Science.gov (United States)

Graczyk, Halshka; Lewinski, Nastassja; Zhao, Jiayuan; Concha-Lozano, Nicolas; Riediker, Michael

2016-01-01

Tungsten inert gas welding (TIG) represents one of the most widely used metal joining processes in industry. Its propensity to generate a greater portion of welding fume particles at the nanoscale poses a potential occupational health hazard for workers. However, current literature lacks comprehensive characterization of TIG welding fume particles. Even less is known about welding fumes generated by welding apprentices with little experience in welding. We characterized TIG welding fume generated by apprentice welders (N = 20) in a ventilated exposure cabin. Exposure assessment was conducted for each apprentice welder at the breathing zone (BZ) inside of the welding helmet and at a near-field (NF) location, 60cm away from the welding task. We characterized particulate matter (PM4), particle number concentration and particle size, particle morphology, chemical composition, reactive oxygen species (ROS) production potential, and gaseous components. The mean particle number concentration at the BZ was 1.69E+06 particles cm−3, with a mean geometric mean diameter of 45nm. On average across all subjects, 92% of the particle counts at the BZ were below 100nm. We observed elevated concentrations of tungsten, which was most likely due to electrode consumption. Mean ROS production potential of TIG welding fumes at the BZ exceeded average concentrations previously found in traffic-polluted air. Furthermore, ROS production potential was significantly higher for apprentices that burned their metal during their welding task. We recommend that future exposure assessments take into consideration welding performance as a potential exposure modifier for apprentice welders or welders with minimal training. PMID:26464505

Effects on the efficiency of activated carbon on exposure to welding fumes

Energy Technology Data Exchange (ETDEWEB)

Ghosh, D. [Southern Company Services, Inc., Birmingham, AL (United States)

1995-02-01

It is the intention of this paper to document that certain types of welding fumes have little or no effect on the effectiveness of the carbon filter air filtration efficiency when directly exposed to a controlled amount of welding fumes for a short-term period. The welding processes studied were restricted to shielded metal arc welding (SMAW), flux cored arc welding (FCAW), gas tungsten arc welding (GTAW) and gas metal arc welding (GMAW) processes. Contrary to the SMAW and FCAW processes, the GTAW (or TIG) and the GMAW (or MIG) welding processes do not require the use of flux as part of the overall process. Credit was taken for these processes occurring in inert gas environments and producing minimal amount of smoke. It was concluded that a study involving the SMAW process would also envelop the effects of the TIG and MIG welding processes. The quantity of welding fumes generated during the arc welding process is a function of the particular process, the size and type of electrode, welding machine amperage, and operator proficiency. For this study, the amount of welding for specific testing was equated to the amount of welding normally conducted during plant unit outages. Different welding electrodes were also evaluated, and the subsequent testing was limited to an E7018 electrode which was judged to be representative of all carbon and stainless steel electrodes commonly used at the site. The effect of welding fumes on activated charcoal was tested using a filtration unit complete with prefilters, upstream and downstream high efficiency particulate air (HEPA) filters, and a carbon adsorber section. The complete system was field tested in accordance with ANSI N510 standards prior to exposing the filters and the adsorber bed to welding fumes. The carbon samples were tested at an established laboratory using ASTM D3803-1989 standards.

Welding fume exposure and chronic obstructive pulmonary disease in welders.

Science.gov (United States)

Koh, D-H; Kim, J-I; Kim, K-H; Yoo, S-W

2015-01-01

Occupational exposure is estimated to contribute 15% to the burden of chronic obstructive pulmonary disease (COPD). Welding fumes are suspected to accelerate the decline of lung function and development of COPD. To examine the relationship between welding fume exposure and COPD in Korean shipyard welders. The study involved a group of male welders working at two shipyards who underwent an annual health examination in 2010. Subjects completed a questionnaire about smoking habits and occupational history and a pulmonary function test (PFT) was carried out with strict quality control measures. Welding fume exposure concentrations were estimated using 884 measurements taken between 2002 and 2009 in one of the shipyards. Multiple linear and logistic regression was employed to evaluate the association between cumulative fume exposure and lung function parameters, controlling for age, height and cigarette smoking. Two hundred and forty subjects participated, with a mean age of 48 and mean work duration of 15 years. The mean cumulative fume exposure was 7.7mg/m(3). The prevalence of COPD was 15%. FEV1 and FVC showed non-significant negative correlations with cumulative fume exposure. Odds ratios of COPD were significantly elevated for the middle (3.9; 95% CI 1.4-13.3) and high exposure groups (3.8; 95% CI 1.03-16.2) compared with the low fume exposure group. Our findings support an association between welding fume exposure and increased risk of COPD. Further prospective study is needed to investigate whether this is a causal relationship. © The Author 2014. Published by Oxford University Press on behalf of the Society of Occupational Medicine. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Characterization of Tungsten Inert Gas (TIG) Welding Fume Generated by Apprentice Welders.

Science.gov (United States)

Graczyk, Halshka; Lewinski, Nastassja; Zhao, Jiayuan; Concha-Lozano, Nicolas; Riediker, Michael

2016-03-01

Tungsten inert gas welding (TIG) represents one of the most widely used metal joining processes in industry. Its propensity to generate a greater portion of welding fume particles at the nanoscale poses a potential occupational health hazard for workers. However, current literature lacks comprehensive characterization of TIG welding fume particles. Even less is known about welding fumes generated by welding apprentices with little experience in welding. We characterized TIG welding fume generated by apprentice welders (N = 20) in a ventilated exposure cabin. Exposure assessment was conducted for each apprentice welder at the breathing zone (BZ) inside of the welding helmet and at a near-field (NF) location, 60cm away from the welding task. We characterized particulate matter (PM4), particle number concentration and particle size, particle morphology, chemical composition, reactive oxygen species (ROS) production potential, and gaseous components. The mean particle number concentration at the BZ was 1.69E+06 particles cm(-3), with a mean geometric mean diameter of 45nm. On average across all subjects, 92% of the particle counts at the BZ were below 100nm. We observed elevated concentrations of tungsten, which was most likely due to electrode consumption. Mean ROS production potential of TIG welding fumes at the BZ exceeded average concentrations previously found in traffic-polluted air. Furthermore, ROS production potential was significantly higher for apprentices that burned their metal during their welding task. We recommend that future exposure assessments take into consideration welding performance as a potential exposure modifier for apprentice welders or welders with minimal training. © The Author 2015. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

Risk of ischemic heart disease following occupational exposure to welding fumes

DEFF Research Database (Denmark)

Mocevic, Emina; Kristiansen, Pernille; Bonde, Jens Peter

2015-01-01

PURPOSE: Air pollution has been linked to an increased risk of ischemic heart disease (IHD), but less is known about occupational exposure to welding fumes and the risk of IHD. The objective of this paper was to review the epidemiological evidence on causal links between welding fume exposure...

Designing, Constructing and Installing a Local Exhaust Ventilation System to Minimize Welders\\' Exposure to Welding Fumes

Directory of Open Access Journals (Sweden)

Sajad Zare

2017-10-01

Full Text Available Background & Aims of the Study: Welder’s exposure to welding fumes can cause occupational diseases. The current study sought to examine exposure to welding fumes among welders who work in the repair shop of Sarcheshmeh Copper Complex and design a local exhaust ventilation system to control exposure to welding fumes. Materials & Methods: This applied analytical study was conducted in the summer of 2016 among welders working in the repair shop of Sarcheshmeh Copper Complex. The study comprised three phases; in the first one, welders’ exposure to welding fumes was assessed at the beginning of the study. After that, a local exhaust ventilation system was designed and installed in the aforementioned repair shop. In the final stage, welders’ exposure to welding fumes was assessed again after installation of the ventilation system. The procedure recommended by NIOSH (method number 7300 was used for individual sampling of welders. Results: Based on the obtained findings, before installing the ventilation system, welding technicians were exposed to 0.3 mg/m3 of copper fumes and 0.04 mg/m3 of chromium fumes. Journeyman welders were also exposed to 2.16 mg/m3 of manganese fumes, while stellar welders were exposed to 6.9 mg/m3 of iron fumes. In the light of these measurements, a local exhaust ventilation system was designed and installed. Subsequently, measurement of exposure to welding fumes showed a significant reduction. That is, welding technicians were exposed to 0.17 mg/m3 and 0.015 mg/m3 of copper and chromium fumes respectively. Additionally, journeyman welders were exposed to 0.86 mg/m3 of manganese fumes, whereas stellar welders were exposed to 4.3 mg/m3 of iron fumes. Conclusions: A comparison of standard limits of exposure to welding fumes and the results obtained from measurements in sampling stations before and after the installation of the local exhaust ventilation system reveals that this controlling measure was very effective in the

Detailed characterization of welding fumes in personal exposure samples

International Nuclear Information System (INIS)

Quémerais, B; Mino, James; Amin, M R; Golshahi, H; Izadi, H

2015-01-01

The objective of the project was to develop a method allowing for detailed characterization of welding particles including particle number concentration, size distribution, surface chemistry and chemical composition of individual particles, as well as metal concentration of various welding fumes in personal exposure samples using regular sampling equipment. A sample strategy was developed to evaluate the variation of the collection methods on mass concentration. Samples were collected with various samplers and filters at two different locations using our collection system. The first location was using a robotic welding system while the second was manual welding. Collected samples were analysed for mass concentration using gravimetryand metal concentration using ICP/OES. More advanced analysis was performed on selected filters using X-Ray Photoelectron Spectroscopy to determine surface composition of the particles, and X-Ray Diffraction to determine chemical composition of the fumes. Results showed that the robotic system had a lot of variation in space when the collection system was located close to the weld. Collection efficiency was found to be quite variable depending upon the type of filter. As well, metal concentrations in blank filters were dependent upon the type of filter with MCE presenting with the highest blank values. Results obtained with the XRD and XPS systems showed that it was possible to analyse a small of powdered welding fume sample but results on filters were not conclusive. (paper)

Profiling mild steel welding processes to reduce fume emissions and costs in the workplace.

Science.gov (United States)

Keane, Michael J; Siert, Arlen; Chen, Bean T; Stone, Samuel G

2014-05-01

To provide quantitative information to choose the best welding processes for minimizing workplace emissions, nine gas metal arc welding (GMAW) processes for mild steel were assessed for fume generation rates, normalized fume generation rates (milligram fume per gram of electrode consumed), and normalized generation rates for elemental manganese, nickel, and iron. Shielded metal arc welding (SMAW) and flux-cored arc-welding (FCAW) processes were also profiled. The fumes were collected quantitatively in an American Welding Society-type fume chamber and weighed, recovered, homogenized, and analyzed by inductively coupled atomic emission spectroscopy for total metals. The processes included GMAW with short circuit, globular transfer, axial spray, pulsed spray, Surface Tension Transfer™, Regulated Metal Deposition™, and Cold Metal Transfer™ (CMT) modes. Flux-cored welding was gas shielded, and SMAW was a single rod type. Results indicate a wide range of fume emission factors for the process variations studied. Fume emission rates per gram of electrode consumed were highest for SMAW (~13 mg fume g(-1) electrode) and lowest for GMAW processes such as pulsed spray (~1.5mg g(-1)) and CMT (~1mg g(-1)). Manganese emission rates per gram of electrode consumed ranged from 0.45 mg g(-1) (SMAW) to 0.08 mg g(-1) (CMT). Nickel emission rates were generally low and ranged from ~0.09 (GMAW short circuit) to 0.004 mg g(-1) (CMT). Iron emission rates ranged from 3.7 (spray-mode GMAW) to 0.49 mg g(-1) (CMT). The processes studied have significantly different costs, and cost factors are presented based on a case study to allow comparisons between processes in specific cost categories. Costs per linear meter of weld were $31.07 (SMAW), $12.37 (GMAW short circuit), and $10.89 (FCAW). Although no single process is the best for minimizing fume emissions and costs while satisfying the weld requirements, there are several processes that can minimize emissions. This study provides

Number size distribution of fine and ultrafine fume particles from various welding processes.

Science.gov (United States)

Brand, Peter; Lenz, Klaus; Reisgen, Uwe; Kraus, Thomas

2013-04-01

Studies in the field of environmental epidemiology indicate that for the adverse effect of inhaled particles not only particle mass is crucial but also particle size is. Ultrafine particles with diameters below 100 nm are of special interest since these particles have high surface area to mass ratio and have properties which differ from those of larger particles. In this paper, particle size distributions of various welding and joining techniques were measured close to the welding process using a fast mobility particle sizer (FMPS). It turned out that welding processes with high mass emission rates (manual metal arc welding, metal active gas welding, metal inert gas welding, metal inert gas soldering, and laser welding) show mainly agglomerated particles with diameters above 100 nm and only few particles in the size range below 50 nm (10 to 15%). Welding processes with low mass emission rates (tungsten inert gas welding and resistance spot welding) emit predominantly ultrafine particles with diameters well below 100 nm. This finding can be explained by considerably faster agglomeration processes in welding processes with high mass emission rates. Although mass emission is low for tungsten inert gas welding and resistance spot welding, due to the low particle size of the fume, these processes cannot be labeled as toxicologically irrelevant and should be further investigated.

Soluble transition metals cause the pro-inflammatory effects of welding fumes in vitro

International Nuclear Information System (INIS)

McNeilly, Jane D.; Heal, Mathew R.; Beverland, Iain J.; Howe, Alan; Gibson, Mark D.; Hibbs, Leon R.; MacNee, William; Donaldson, Ken

2004-01-01

Epidemiological studies have consistently reported a higher incidence of respiratory illnesses such as bronchitis, metal fume fever (MFF), and chronic pneumonitis among welders exposed to high concentrations of metal-enriched welding fumes. Here, we studied the molecular toxicology of three different metal-rich welding fumes: NIMROD 182, NIMROD c276, and COBSTEL 6. Fume toxicity in vitro was determined by exposing human type II alveolar epithelial cell line (A549) to whole welding fume, a soluble extract of fume or the 'washed' particulate. All whole fumes were significantly toxic to A549 cells at doses >63 μg ml -1 (TD 50; 42, 25, and 12 μg ml -1 , respectively). NIMROD c276 and COBSTEL 6 fumes increased levels of IL-8 mRNA and protein at 6 h and protein at 24 h, as did the soluble fraction alone, whereas metal chelation of the soluble fraction using chelex beads attenuated the effect. The soluble fraction of all three fumes caused a rapid depletion in intracellular glutathione following 2-h exposure with a rebound increase by 24 h. In addition, both nickel based fumes, NIMROD 182 and NIMROD c276, induced significant reactive oxygen species (ROS) production in A549 cells after 2 h as determined by DCFH fluorescence. ICP analysis confirmed that transition metal concentrations were similar in the whole and soluble fractions of each fume (dominated by Cr), but significantly less in both the washed particles and chelated fractions. These results support the hypothesis that the enhanced pro-inflammatory responses of welding fume particulates are mediated by soluble transition metal components via an oxidative stress mechanism

Risk communication concerning welding fumes for the primary preventive care of welding apprentices in southern Brazil.

Science.gov (United States)

Cezar-Vaz, Marta Regina; Bonow, Clarice Alves; Vaz, Joana Cezar

2015-01-19

This study's aim was to assess the perceptions of welding apprentices concerning welding fumes being associated with respiratory and cardiovascular disorders and assess the implementation of risk communication as a primary prevention tool in the welding training process. This quasi-experimental, non-randomized study with before-and-after design was conducted with 84 welding apprentices in Southern Brazil. Poisson Regression analysis was used. Relative Risk was the measure used with a 95% confidence interval and 5% (p ≤ 0.05) significance level. Significant association was found between perceptions of worsened symptoms of respiratory disorders caused by welding fumes and educational level (p = 0.049), the use of goggles to protect against ultraviolet rays (p = 0.023), and access to services in private health facilities without insurance coverage (p = 0.001). Apprentices younger than 25 years old were 4.9 times more likely to perceive worsened cardiovascular symptoms caused by welding fumes after risk communication (RR = 4.91; CI 95%: 1.09 to 22.2). The conclusion is that risk communication as a primary preventive measure in continuing education processes implemented among apprentices, who are future welders, was efficacious. Thus, this study confirms that risk communication can be implemented as a primary prevention tool in welding apprenticeships.

Workplace field testing of the pressure drop of particulate respirators using welding fumes.

Science.gov (United States)

Cho, Hyun-Woo; Yoon, Chung-Sik

2012-10-01

In a previous study, we concluded that respirator testing with a sodium chloride aerosol gave a conservative estimate of filter penetration for welding fume aerosols. A rapid increase in the pressure drop (PD) of some respirators was observed as fumes accumulated on the filters. The present study evaluated particulate respirator PD based on workplace field tests. A field PD tester was designed and validated using the TSI 8130 Automatic Filter Tester, designed in compliance with National Institute for Occupational and Safety and Health regulation 42 CFR part 84. Three models (two replaceable dual-type filters and one replaceable single-type filter) were evaluated against CO(2) gas arc welding on mild steel in confined booths in the workplace. Field tests were performed under four airborne concentrations (27.5, 15.4, 7.9, and 2.1 mg m(-3)). The mass concentration was measured by the gravimetric method, and number concentration was monitored using P-Trak (Model 8525, TSI, USA). Additionally, photos and scanning electron microscopy-energy dispersive X-ray spectroscopy were used to visualize and analyze the composition of welding fumes trapped in the filters. The field PD tester showed no significant difference compared with the TSI tester. There was no significant difference in the initial PD between laboratory and field results. The PD increased as a function of fume load on the respirator filters for all tested models. The increasing PD trend differed by models, and PD increased rapidly at high concentrations because greater amount of fumes accumulated on the filters in a given time. The increase in PD as a function of fume load on the filters showed a similar pattern as fume load varied for a particular model, but different patterns were observed for different models. Images and elemental analyses of fumes trapped on the respirator filters showed that most welding fumes were trapped within the first layer, outer web cover, and second layer, in order, while no fumes

Effects of Exposure to Welding Fume on Lung Function: Results from the German WELDOX Study.

Science.gov (United States)

Lehnert, M; Hoffmeyer, F; Gawrych, K; Lotz, A; Heinze, E; Berresheim, H; Merget, R; Harth, V; Van Gelder, R; Hahn, J-U; Hartwig, A; Weiß, T; Pesch, B; Brüning, T

2015-01-01

The association between exposure to welding fume and chronic obstructive pulmonary disease (COPD) has been insufficiently clarified. In this study we assessed the influence of exposure to welding fume on lung function parameters. We investigated forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC), FEV1/FVC, and expiratory flow rates in 219 welders. We measured current exposure to respirable particles and estimated a worker's lifetime exposure considering welding techniques, working conditions and protective measures at current and former workplaces. Multiple regression models were applied to estimate the influence of exposure to welding fume, age, and smoking on lung function. We additionally investigated the duration of working as a welder and the predominant welding technique. The findings were that age- and smoking-adjusted lung function parameters showed no decline with increasing duration, current exposure level, and lifetime exposure to welding fume. However, 15% of the welders had FEV1/FVC below the lower limit of normal, but we could not substantiate the presence of an association with the measures of exposure. Adverse effects of cigarette smoking were confirmed. In conclusion, the study did not support the notion of a possible detrimental effect of exposure to welding fume on lung function in welders.

Effects of welding fumes on nuclear air cleaning system carbon adsorber banks

Energy Technology Data Exchange (ETDEWEB)

Roberson, P.W. [Duke Power Company, Huntersville, NC (United States)

1997-08-01

Standard Technical Specifications for nuclear air cleaning systems include requirements for surveillance tests following fire, painting, or chemical release in areas communicating with the affected system. To conservatively implement this requirement, many plants categorize welding as a chemical release process, and institute controls to ensure that welding fumes do not interact with carbon adsorbers in a filter system. After reviewing research data that indicated welding had a minimal impact on adsorber iodine removal efficiency, further testing was performed with the goal of establishing a welding threshold. It was anticipated that some quantity of weld electrodes could be determined that had a corresponding detrimental impact on iodine removal efficiency for the exposed adsorber. This value could be used to determine a conservative sampling schedule that would allow the station to perform laboratory testing to ensure system degradation did not occur without a full battery of surveillance tests. A series of tests was designed to demonstrate carbon efficiency versus cumulative welding fume exposure. Three series of tests were performed, one for each of three different types of commonly used weld electrodes. Carbon sampling was performed at baseline conditions, and every five pounds of electrode thereafter. Two different laboratory tests were performed for each sample; one in accordance with ASTM 3803/1989 at 95% relative humidity and 30 degrees C, and another using the less rigorous conditions of 70% relative humidity and 80 degrees C. Review of the test data for all three types of electrodes failed to show a significant correlation between carbon efficiency degradation and welding fume exposure. Accordingly, welding is no longer categorized as a `chemical release process` at McGuire Nuclear Station, and limits on welding fume interaction with ventilation systems have been eliminated. 4 refs., 3 figs., 1 tab.

Performance of laboratories analysing welding fume on filter samples: results from the WASP proficiency testing scheme.

Science.gov (United States)

Stacey, Peter; Butler, Owen

2008-06-01

This paper emphasizes the need for occupational hygiene professionals to require evidence of the quality of welding fume data from analytical laboratories. The measurement of metals in welding fume using atomic spectrometric techniques is a complex analysis often requiring specialist digestion procedures. The results from a trial programme testing the proficiency of laboratories in the Workplace Analysis Scheme for Proficiency (WASP) to measure potentially harmful metals in several different types of welding fume showed that most laboratories underestimated the mass of analyte on the filters. The average recovery was 70-80% of the target value and >20% of reported recoveries for some of the more difficult welding fume matrices were welding fume trial filter samples. Consistent rather than erratic error predominated, suggesting that the main analytical factor contributing to the differences between the target values and results was the effectiveness of the sample preparation procedures used by participating laboratories. It is concluded that, with practice and regular participation in WASP, performance can improve over time.

Assessment of the Biological Effects of Welding Fumes Emitted From Metal Active Gas and Manual Metal Arc Welding in Humans.

Science.gov (United States)

Dewald, Eva; Gube, Monika; Baumann, Ralf; Bertram, Jens; Kossack, Veronika; Lenz, Klaus; Reisgen, Uwe; Kraus, Thomas; Brand, Peter

2015-08-01

Emissions from a particular welding process, metal inert gas brazing of zinc-coated steel, induce an increase in C-reactive protein. In this study, it was investigated whether inflammatory effects could also be observed for other welding procedures. Twelve male subjects were separately exposed to (1) manual metal arc welding fumes, (2) filtered air, and (3) metal active gas welding fumes for 6 hours. Inflammatory markers were measured in serum before, and directly, 1 and 7 days after exposure. Although C-reactive protein concentrations remained unchanged, neutrophil concentrations increased directly after exposure to manual metal arc welding fumes, and endothelin-1 concentrations increased directly and 24 hours after exposure. After exposure to metal active gas and filtered air, endothelin-1 concentrations decreased. The increase in the concentrations of neutrophils and endothelin-1 may characterize a subclinical inflammatory reaction, whereas the decrease of endothelin-1 may indicate stress reduction.

Microarray-based analysis of the lung recovery process after stainless-steel welding fume exposure in Sprague-Dawley rats.

Science.gov (United States)

Oh, Jung-Hwa; Yang, Mi-jin; Yang, Young-Su; Park, Han-Jin; Heo, Sun Hee; Lee, Eun-Hee; Song, Chang-Woo; Yoon, Seokjoo

2009-02-01

Repeated exposure to welding fumes promotes a reversible increase in pulmonary disease risk, but the molecular mechanisms by which welding fumes induce lung injury and how the lung recovers from such insults are unclear. In the present study, pulmonary function and gene-expression profiles in the lung were analyzed by Affymetrix GeneChip microarray after 30 days of consecutive exposure to manual metal arc welding combined with stainless-steel (MMA-SS) welding fumes, and again after 30 days of recovery from MMA-SS fume exposure. In total, 577 genes were identified as being either up-regulated or down-regulated (over twofold changes, p process of the lung were up-regulated exclusively in the recovery group. Collectively, these data may help elucidate the molecular mechanism of the recovery process of the lung after welding fume exposure.

Systemic inflammatory responses following welding inhalation challenge test

Directory of Open Access Journals (Sweden)

Paula Kauppi

2015-01-01

Conclusions: Exposure to MS and SS welding fume resulted in a mild systemic inflammatory response. The particle concentration from the breathing zones correlated with the measurements inside the welding face shields.

Local exhaust ventilation for the control of welding fumes in the construction industry--a literature review.

Science.gov (United States)

Flynn, Michael R; Susi, Pam

2012-08-01

Arc welding is a common unit operation in the construction industry, where frequent changes in location and welding position make it more difficult to control fume exposures than in industries where fixed locations are the norm. Welders may be exposed to a variety of toxic airborne contaminants including manganese (Mn) and hexavalent chromium (CrVI). Local exhaust ventilation (LEV) is a well-known engineering control for welding fumes but has not been adopted widely in the construction industry. This literature review presents data on the performance of a variety of LEV systems for welding fume control from the construction (five references), shipyard (five references), and other industries. The studies indicate that LEV can reduce fume exposures to total particulate, Mn, and CrVI to levels below currently relevant standards. Field studies suggest that 40-50% or more reduction in exposure is possible with portable or fixed LEV systems relative to natural ventilation but that correct positioning of the hood and adequate exhaust flow rates are essential. Successful implementation of extraction guns for gas metal arc welding (GMAW) and flux core arc welding has been demonstrated, indicating that a successful balance between extraction airflow and shielding gas requirements is possible. Work practices are an important part of achieving successful control of fume exposures; in particular, positioning the hood close to the arc, checking exhaust flow rates, and avoiding the plume. Further research is needed on hood size effects for controlling welding fume with portable LEV systems and identifying and overcoming barriers to LEV use in construction.

The Relationship of Welding Fume Exposure, Smoking, and Pulmonary Function in Welders.

Science.gov (United States)

Roach, Laura L

2018-01-01

The purpose of this study was to explore the relationship between occupational exposure to welding fumes and pulmonary function in an effort to add supportive evidence and clarity to the current body of research. This study utilized a retrospective chart review of pulmonary function testing and pulmonary questionnaires already available in charts from preplacement physicals to the most recent test. When comparing smokers to nonsmokers, utilizing multiple regression and controlling for age and percentage of time using a respirator, years welding was statistically significant at p = .04. Data support that smoking has a synergistic effect when combined with welding fume exposure on pulmonary decline.

Alterations in cardiomyocyte function after pulmonary treatment with stainless steel welding fume in rats.

Science.gov (United States)

Popstojanov, Risto; Antonini, James M; Salmen, Rebecca; Ye, Morgan; Zheng, Wen; Castranova, Vincent; Fekedulegn, Desta B; Kan, Hong

2014-01-01

Welding fume is composed of a complex of different metal particulates. Pulmonary exposure to different welding fumes may exert a negative impact on cardiac function, although the underlying mechanisms remain unclear. To explore the effect of welding fumes on cardiac function, Sprague-Dawley rats were exposed by intratracheal instillation to 2 mg/rat of manual metal arc hard surfacing welding fume (MMA-HS) once per week for 7 wk. Control rats received saline. Cardiomyocytes were isolated enzymatically at d 1 and 7 postexposure. Intracellular calcium ([Ca(2+)]i) transients (fluorescence ratio) were measured on the stage of an inverted phase-contrast microscope using a myocyte calcium imaging/cell length system. Phosphorylation levels of cardiac troponin I (cTnI) were determined by Western blot. The levels of nonspecific inflammatory marker C-reactive protein (CRP) and proinflammatory cytokine interleukin-6 (IL-6) in serum were measured by enzyme-linked immunosorbent assay (ELISA). Contraction of isolated cardiomyocytes was significantly reduced at d 1 and d 7 postexposure. Intracellular calcium levels were decreased in response to extracellular calcium stimulation at d 7 postexposure. Changes of intracellular calcium levels after isoprenaline hydrochloride (ISO) stimulation were not markedly different between groups at either time point. Phosphorylation levels of cTnI in the left ventricle were significantly lower at d 1 postexposure. The serum levels of CRP were not markedly different between groups at either time point. Serum levels of IL-6 were not detectable in both groups. Cardiomyocyte alterations observed after welding fume treatment were mainly due to alterations in intracellular calcium handling and phosphorylation levels of cTnI.

Profiling stainless steel welding processes to reduce fume emissions, hexavalent chromium emissions and operating costs in the workplace.

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Keane, Michael; Siert, Arlen; Stone, Samuel; Chen, Bean T

2016-01-01

Nine gas metal arc welding (GMAW) processes for stainless steel were assessed for fume generation rates, fume generation rates per g of electrode consumed, and emission rates for hexavalent chromium (Cr(6+)). Elemental manganese, nickel, chromium, iron emissions per unit length of weld, and labor plus consumables costs were similarly measured. Flux-cored arc welding and shielded metal arc (SMAW) processes were also studied. The objective was to identify the best welding processes for reducing workplace exposures, and estimate costs for all processes. Using a conical chamber, fumes were collected, weighed, recovered, and analyzed by inductively coupled atomic emission spectroscopy for metals, and by ion chromatography for Cr(6+). GMAW processes used were Surface Tension Transfer, Regulated Metal Deposition, Cold Metal Transfer, short-circuit, axial spray, and pulsed spray modes. Flux-cored welding used gas shielding; SMAW used E308 rods. Costs were estimated as dollars per m length of a ¼ in (6.3 mm) thick horizontal butt weld; equipment costs were estimated as ratios of new equipment costs to a 250 ampere capacity SMAW welding machine. Results indicate a broad range of fume emission factors for the processes studied. Fume emission rates per g of electrode were lowest for GMAW processes such as pulsed-spray mode (0.2 mg/g), and highest for SMAW (8 mg fume/g electrode). Emission rates of Cr(6+) ranged from 50-7800 µg/min, and Cr(6+) generation rates per g electrode ranged from 1-270 µg/g. Elemental Cr generation rates spanned 13-330 µg/g. Manganese emission rates ranged from 50-300 µg/g. Nickel emission rates ranged from 4-140 µg/g. Labor and consumables costs ranged from $3.15 (GMAW pulsed spray) to $7.40 (SMAW) per meter of finished weld, and were measured or estimated for all 11 processes tested. Equipment costs for some processes may be as much as five times the cost of a typical SMAW welding machine. The results show that all of the GMAW processes in this

Response of the mouse lung transcriptome to welding fume: effects of stainless and mild steel fumes on lung gene expression in A/J and C57BL/6J mice

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Antonini James M

2010-06-01

Full Text Available Abstract Background Debate exists as to whether welding fume is carcinogenic, but epidemiological evidence suggests that welders are an at risk population for the development of lung cancer. Recently, we found that exposure to welding fume caused an acutely greater and prolonged lung inflammatory response in lung tumor susceptible A/J versus resistant C57BL/6J (B6 mice and a trend for increased tumor incidence after stainless steel (SS fume exposure. Here, our objective was to examine potential strain-dependent differences in the regulation and resolution of the lung inflammatory response induced by carcinogenic (Cr and Ni abundant or non-carcinogenic (iron abundant metal-containing welding fumes at the transcriptome level. Methods Mice were exposed four times by pharyngeal aspiration to 5 mg/kg iron abundant gas metal arc-mild steel (GMA-MS, Cr and Ni abundant GMA-SS fume or vehicle and were euthanized 4 and 16 weeks after the last exposure. Whole lung microarray using Illumina Mouse Ref-8 expression beadchips was done. Results Overall, we found that tumor susceptibility was associated with a more marked transcriptional response to both GMA-MS and -SS welding fumes. Also, Ingenuity Pathway Analysis revealed that gene regulation and expression in the top molecular networks differed between the strains at both time points post-exposure. Interestingly, a common finding between the strains was that GMA-MS fume exposure altered behavioral gene networks. In contrast, GMA-SS fume exposure chronically upregulated chemotactic and immunomodulatory genes such as CCL3, CCL4, CXCL2, and MMP12 in the A/J strain. In the GMA-SS-exposed B6 mouse, genes that initially downregulated cellular movement, hematological system development/function and immune response were involved at both time points post-exposure. However, at 16 weeks, a transcriptional switch to an upregulation for neutrophil chemotactic genes was found and included genes such as S100A8, S100A9 and

Hexavalent chromium content in stainless steel welding fumes is dependent on the welding process and shield gas type.

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Keane, Michael; Stone, Samuel; Chen, Bean; Slaven, James; Schwegler-Berry, Diane; Antonini, James

2009-02-01

Occupational exposure to welding fumes is a known health hazard. To isolate elements in stainless steel welding fumes with high potential for adverse health outcomes, fumes were generated using a robotic gas metal arc system, using four shield gases of varying oxygen content. The objective was to measure Cr(VI) concentrations in a broad spectrum of gas metal arc welding processes, and identify processes of exceptionally high or low Cr(VI) content. The gases used were 95% Ar/5% O(2), 98% Ar/2% O(2), 95% Ar/5%CO(2), and 75% He/25% Ar. The welder was operated in axial spray mode (Ar/O(2), Ar/CO(2)), short-circuit (SC) mode (Ar/CO(2) low voltage and He/Ar), and pulsed axial-spray mode (98% Ar/2% O(2)). Results indicate large differences in Cr(VI) in the fumes, with Ar/O(2) (Pulsed)>Ar/O(2)>Ar/CO(2)>Ar/CO(2) (SC)>He/Ar; values were 3000+/-300, 2800+/-85, 2600+/-120, 1400+/-190, and 320+/-290 ppm respectively (means +/- standard errors for 2 runs and 3 replicates per run). Respective rates of Cr(VI) generation were 1.5, 3.2, 4.4, 1.3, and 0.46 microg/min; generation rates were also calculated in terms of microg Cr(VI) per metre of wire used. The generation rates of Cr(VI) increased with increasing O(3) concentrations. Particle size measurements indicated similar distributions, but somewhat higher >0.6 microm fractions for the short-circuit mode samples. Fumes were also sampled into 2 selected size ranges, a microspatter fraction (>or=0.6 microm) and a fine (welding type and shield gas type, and this presents an opportunity to tailor welding practices to lessen Cr(VI) exposures in workplaces by selecting low Cr(VI)-generating processes. Short-circuit processes generated less Cr(VI) than axial-spray methods, and inert gas shielding gave lower Cr(VI) content than shielding with active gases. A short circuit He/Ar shielded process and a pulsed axial spray Ar/O(2) process were both identified as having substantially lower Cr(VI) generation rates per unit of wire used relative

Effect Of Inhalation Exposure To Kerosene And Petrol-Fumes On ...

African Journals Online (AJOL)

Changes in total body weight, some anaemia-diagnostic indices (haematocrit or packed cell volume (PCV), haemoglobin (Hb) and total serum protein) were determined in rats (Wistar albino strain) after 2 weeks of 4 hours daily inhalation exposure to ungraded concentrations of kerosene and petrol fumes. The results ...

Altered ion transport in normal human bronchial epithelial cells following exposure to chemically distinct metal welding fume particles

Energy Technology Data Exchange (ETDEWEB)

Fedan, Jeffrey S., E-mail: jsf2@cdc.gov; Thompson, Janet A.; Meighan, Terence G.; Zeidler-Erdely, Patti C.; Antonini, James M.

2017-07-01

Welding fume inhalation causes pulmonary toxicity, including susceptibility to infection. We hypothesized that airway epithelial ion transport is a target of fume toxicity, and investigated the effects of fume particulates from manual metal arc-stainless steel (MMA-SS) and gas metal arc-mild steel (GMA-MS) on ion transport in normal human bronchial epithelium (NHBE) cultured in air-interface. MMA-SS particles, more soluble than GMA-MS particles, contain Cr, Ni, Fe and Mn; GMA-MS particles contain Fe and Mn. MMA-SS or GMA-MS particles (0.0167–166.7 μg/cm{sup 2}) were applied apically to NHBEs. After 18 h transepithelial potential difference (V{sub t}), resistance (R{sub t}), and short circuit current (I{sub sc}) were measured. Particle effects on Na{sup +} and Cl¯ channels and the Na{sup +},K{sup +},2Cl¯-cotransporter were evaluated using amiloride (apical), 5-nitro-2-[(3-phenylpropyl)amino]benzoic acid (NPPB, apical), and bumetanide (basolateral), respectively. MMA-SS (0.0167–16.7 μg/cm{sup 2}) increased basal V{sub t}. Only 16.7 μg/cm{sup 2} GMA-MS increased basal V{sub t} significantly. MMA-SS or GMA-MS exposure potentiated I{sub sc} responses (decreases) to amiloride and bumetanide, while not affecting those to NPPB, GMA-MS to a lesser degree than MMA-SS. Variable effects on R{sub t} were observed in response to amiloride, and bumetanide. Generally, MMA-SS was more potent in altering responses to amiloride and bumetanide than GMA-MS. Hyperpolarization occurred in the absence of LDH release, but decreases in V{sub t}, R{sub t}, and I{sub sc} at higher fume particulate doses accompanied LDH release, to a greater extent for MMA-SS. Thus, Na{sup +} transport and Na{sup +},K{sup +},2Cl¯-cotransport are affected by fume exposure; MMA-MS is more potent than GMA-MS. Enhanced Na{sup +} absorption and decreased airway surface liquid could compromise defenses against infection. - Highlights: • Welding fume particle toxicity was investigated in human bronchial

Welding fumes from stainless steel gas metal arc processes contain multiple manganese chemical species.

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Keane, Michael; Stone, Samuel; Chen, Bean

2010-05-01

Fumes from a group of gas metal arc welding (GMAW) processes used on stainless steel were generated using three different metal transfer modes and four different shield gases. The objective was to identify and measure manganese (Mn) species in the fumes, and identify processes that are minimal generators of Mn species. The robotic welding system was operated in short-circuit (SC) mode (Ar/CO2 and He/Ar), axial spray (AXS) mode (Ar/O2 and Ar/CO2), and pulsed axial-spray (PAXS) mode (Ar/O2). The fumes were analyzed for Mn by a sequential extraction process followed by inductively coupled plasma-atomic emission spectroscopy (ICP-AES) analysis, and by X-ray diffraction (XRD). Total elemental Mn, iron (Fe), chromium (Cr) and nickel (Ni) were separately measured after aqua regia digestion and ICP-AES analysis. Soluble Mn2+, Fe2+, Fe3+, and Ni2+ in a simple biological buffer (phosphate-buffered saline) were determined at pH 7.2 and 5.0 after 2 h incubation at 37 C by ion chromatography. Results indicate that Mn was present in soluble form, acid-soluble form, and acid-soluble form after reduction by hydroxylamine, which represents soluble Mn0 and Mn2+ compounds, other Mn2+ compounds, and (Mn3+ and Mn4+) compounds, respectively. The dominant fraction was the acid-soluble Mn2+ fraction, but results varied with the process and shield gas. Soluble Mn mass percent in the fume ranged from 0.2 to 0.9%, acid-soluble Mn2+ compounds ranged from 2.6 to 9.3%, and acid plus reducing agent-soluble (Mn3+ and Mn4+) compounds ranged from 0.6 to 5.1%. Total Mn composition ranged from 7 to 15%. XRD results showed fumes had a crystalline content of 90-99% Fe3O4, and showed evidence of multiple Mn oxides, but overlaps and weak signals limited identification. Small amounts of the Mn2+ in the fume (welding process. Mn generation rates for the fractions were tabulated, and the influence of ozone is discussed. The conclusions are that exposures to welding fumes include multiple Mn species, both

Exposure to welding fumes increases lung cancer risk among light smokers but not among heavy smokers: evidence from two case-control studies in Montreal.

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Vallières, Eric; Pintos, Javier; Lavoué, Jérôme; Parent, Marie-Élise; Rachet, Bernard; Siemiatycki, Jack

2012-08-01

We investigated relationships between occupational exposure to gas and arc welding fumes and the risk of lung cancer among workers exposed to these agents throughout the spectrum of industries. Two population-based case-control studies were conducted in Montreal. Study I (1979-1986) included 857 cases and 1066 controls, and Study II (1996-2001) comprised 736 cases and 894 controls. Detailed job histories were obtained by interview and evaluated by an expert team of chemist-hygienists to estimate degree of exposure to approximately 300 substances for each job. Gas and arc welding fumes were among the agents evaluated. We estimated odds ratios (ORs) and 95% confidence intervals (CIs) of lung cancer using logistic regression, adjusting for smoking history and other covariates. The two studies provided similar results, so a pooled analysis was conducted. Among all subjects, no significant association was found between lung cancer and gas welding fumes (OR = 1.1; 95% CI = 0.9-1.4) or arc welding fumes (OR = 1.0; 95% CI = 0.8-1.2). However, when restricting attention to light smokers, there was an increased risk of lung cancer in relation to gas welding fumes (OR = 2.9; 95% CI = 1.7-4.8) and arc welding fumes (OR = 2.3; 95% CI = 1.3-3.8), with even higher OR estimates among workers with the highest cumulative exposures. In conclusion, there was no detectable excess risk of lung cancer due to welding fumes among moderate to heavy smokers; but among light smokers we found an excess risk related to both types of welding fumes.

Acute Inhalation Exposure to Titanium Ethanolate as a Possible Cause of Metal Fume Fever

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M Ahmadimanesh

2014-04-01

Full Text Available Occupational inhalation exposure to noxious agents is not uncommon. Herein, we present a 26-year-old male student who had accidental acute inhalation exposure to a large quantity of titanium ethanolate and hydrogen chloride in chemistry lab. He was referred to the emergency department of our hospital with low-grade fever, dyspnea, headache, fatigue and myalgia. After 24 hrs of symptomatic treatment (oxygen therapy and acetaminophen, the fever was subsided and the patient discharged home in a good clinical condition. The presented symptoms could be interpreted as a form of metal fume fever. It can therefore be concluded that organo-metallic compound of titanium metal may have the potential to produce metal fume fever in human.

Systemic serum amyloid A as a biomarker for exposure to zinc and/or copper-containing metal fumes.

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Baumann, R; Gube, M; Markert, A; Davatgarbenam, S; Kossack, V; Gerhards, B; Kraus, T; Brand, P

2018-01-01

Zinc- and copper-containing welding fumes increase systemic C-reactive protein (CRP). The aim of this study was to investigate the performance of the biomarkers serum amyloid A (SAA) and soluble vascular cell adhesion molecule-1 (VCAM-1) in this regard. Fifteen male subjects were exposed under controlled conditions to welding fumes containing either zinc, or copper, or copper and zinc for 6 h. Plasma samples were collected before, 6 and 24 h after start of exposure and biomarkers therein were measured by electrochemiluminescent assay. For each exposure, systemic concentrations of systemic SAA, but not VCAM-1, increased significantly at 24 h after exposure start compared with baseline ("copper only": P=0.0005, "zinc only": P=0.027, "copper and zinc": P=0.001). SAA showed a wider range of concentrations than did CRP and its levels increased up to 19-fold after welding fume exposure. The recognition of copper as a potential harmful component in welding fumes, also independent from zinc, deserves further consideration. SAA might represent a new sensitive biomarker for potential subclinical sterile inflammation after inhalation of copper- and/or zinc-containing welding fumes. As elevations of CRP and SAA protein have both been linked to a higher risk for cardiovascular disease, these findings might particularly be important for long-term welders.

Exposure to welding fumes increases lung cancer risk among light smokers but not among heavy smokers: evidence from two case–control studies in Montreal

Science.gov (United States)

Vallières, Eric; Pintos, Javier; Lavoué, Jérôme; Parent, Marie-Élise; Rachet, Bernard; Siemiatycki, Jack

2012-01-01

We investigated relationships between occupational exposure to gas and arc welding fumes and the risk of lung cancer among workers exposed to these agents throughout the spectrum of industries. Two population-based case–control studies were conducted in Montreal. Study I (1979–1986) included 857 cases and 1066 controls, and Study II (1996–2001) comprised 736 cases and 894 controls. Detailed job histories were obtained by interview and evaluated by an expert team of chemist–hygienists to estimate degree of exposure to approximately 300 substances for each job. Gas and arc welding fumes were among the agents evaluated. We estimated odds ratios (ORs) and 95% confidence intervals (CIs) of lung cancer using logistic regression, adjusting for smoking history and other covariates. The two studies provided similar results, so a pooled analysis was conducted. Among all subjects, no significant association was found between lung cancer and gas welding fumes (OR = 1.1; 95% CI = 0.9–1.4) or arc welding fumes (OR = 1.0; 95% CI = 0.8–1.2). However, when restricting attention to light smokers, there was an increased risk of lung cancer in relation to gas welding fumes (OR = 2.9; 95% CI = 1.7–4.8) and arc welding fumes (OR = 2.3; 95% CI = 1.3–3.8), with even higher OR estimates among workers with the highest cumulative exposures. In conclusion, there was no detectable excess risk of lung cancer due to welding fumes among moderate to heavy smokers; but among light smokers we found an excess risk related to both types of welding fumes. PMID:23342253

The Study Of Histopathological Effects Of Welding Fumes On Spermatogenesis In Rat

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Arab M R

2005-07-01

Full Text Available Background: Fumes generated during electric welding are one of air pollutants of working place in industrial companies, which can cause some clinical signs and diseases in worker, including mucosal irritation, changing of semen quality and cancer. Chronic exposure of workers with these fumes can cause reduce sperm motility and forward penetration and decrease in normal sperm count. Although a lot of researches were done in this field up to now, there is little information about histopathological effects of these fumes on germinal epithelium. The aim of this study was to identify structural changes of germinal epithelium in Rat as an experimental model after exposure to fumes of electric welding in exposure chamber. Material and Methods: A total number of 60 Sprague Dawley Rats were chosen and divided into experimental (40 and control (20 groups. Each of groups was subdivided into 2, 4, 6 and 8-week subgroups. The number of Rat in each subgroup of experimental and control group was 10 and 5 respectively. Animals were housed in standard situation. After adaptation experimental group were exposed to fumes of electric welding (AMA 2000 electrode, 100 Ampere, 0.1 cm/s speed of electrode welding for 2 hour/day and 5 day/week. The rate of air turn over in exposure chamber was fixed to 12-15/hour. The amount of O3, CO, CO2, NO + NO2 and particulate matter were measured by Galtec detectors and Cellulose acetate filter respectively. According to time table animals were killed and specimens from testis were taken and fixed in formaline buffer solution and processed routinely. Sections with 5-7 micrometer in thickness were stained by H-E, PAS, PNA and Alcian blue pH=2.5. The thickness of germinal epithelium was measured and data were analyzed by Kruskall Wallis test. Results: The results of this study showed a few quantitative and qualitative changes in germinal epithelium. Vasodilatation of vessels in tunica albuginea and interstitial tissue, decreasing of

Phase analysis of fume during arc weld brazing of steel sheets with protective coatings

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J. Matusiak

2016-04-01

Full Text Available The article presents the results of research of the phase identification and of the quantitative phase analysis of fume generated during Cold Metal Transfer (CMT, ColdArc and Metal Inert Gas / Metal Active Gas (MIG / MAG weld brazing. Investigations were conducted for hot - dip coated steel sheets with zinc (Zn and zinc-iron (Zn - Fe alloy coatings. Arc shielding gases applied during the research-related tests were Ar + O2, Ar + CO2, Ar + H2 and Ar + CO2 + H2 gas mixtures. The analysis of the results covers the influence of the chemical composition of shielding gas on the chemical composition of welding fume.

Occupational exposure to solvents, metals and welding fumes and risk of Parkinson's disease.

Science.gov (United States)

van der Mark, Marianne; Vermeulen, Roel; Nijssen, Peter C G; Mulleners, Wim M; Sas, Antonetta M G; van Laar, Teus; Huss, Anke; Kromhout, Hans

2015-06-01

The aim of this study was to investigate the potential association between occupational exposure to solvents, metals and/or welding fumes and risk of developing Parkinson's disease (PD). Data of a hospital based case-control study including 444 PD patients and 876 age and sex matched controls was used. Occupational histories and lifestyle information of cases and controls were collected in a structured telephone interview. Exposures to aromatic solvents, chlorinated solvents and metals were estimated by linking the ALOHA+ job-exposure matrix to the occupational histories. Exposure to welding fumes was estimated using self-reported information on welding activities. No statistically significant associations with any of the studied metal and solvent exposures were found. However, for self-reported welding activities we observed non-statistically significant reduced risk estimates (third tertile cumulative exposure: OR = 0.51 (95% CI: 0.21-1.24)). The results of our study did not provide support for an increased chance on developing PD after occupational exposure to aromatic solvents, chlorinated solvents or exposure to metals. The results showed reduced risk estimates for welding, which is in line with previous research, but no clear explanation for these findings is available. Copyright © 2015 Elsevier Ltd. All rights reserved.

X-ray fluorescence analysis of welding fume particles

International Nuclear Information System (INIS)

Carsey, T.P.

1982-01-01

A commercial standard filter set and two laboratory-made standard filter sets are compared via the analysis of generated welding fume samples by X-ray fluorescence. The latter standards are made by (1) hydrophobic-edge membrane filters spiked with prepared metal ion solutions, and (2) filters through which a dispersion of metal oxide powder in isopropanol has been drawn. The results are presented in table form. Precision (Pre) is the relative standard deviation of the six samples. Four main conclusions are enumerated

Determination of Informal Sector as Urban Pollution Source : Fume Characterization of Small-scale Manual Metal Arc Welding using Factor Analysis in Bandung City

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A. Nastiti

2012-04-01

Full Text Available In developing countries, the informal sector, particularly small-scale welding activities, are considered to be an important contributor to urban air pollution although studies in this sector are limited. This study aims to identify the composition of small-scale welding fume in order to further investigate the effects and set control strategies and urban pollution abatement policies. Breathing zone air samples were collected from 30 mild steel manual metal arc welders and 17 non-welders in Bandung City, West Java, Indonesia. The respirable particulates in air samples were analyzed using gravimetric method, and Instrumental Neutron Activation Analysis (INAA was employed to identify characteristic of welding fume. It was found that respirable particulates concentration in welders (range : 315.6 and 3,735.93 µgm-3; average 1,545.436 µgm-3 were significantly higher than in non-welders (range : 41.84 and 1,688.03 µgm-3; average : 375.783 µgm-3. Welders’ breathing zones contain Fe>Na>K>Mn>Al >Cr>Ti>Cl>Br>I>Zn>Sb>V>Co>Sc; while non-welders’ breathing zones contain Cr>F>Al>Ti>Na>Br>I>Mn>Cl>Co>Zn>Sc. Inter-species correlation analysis conducted using Statgraphic Ver. 4.0 shows that Fe (range : n.d. – 775.19 µgm-3; average: 0.1674 µgm-3, Co (range : n.d. – 0.51 µgm-3; average: 0.000082 µgm-3, Mn (range : 0.39 – 148.37 µgm-3; average: 0.0374 µgm-3, Na (range: 0.17 and 623.85 µgm-3; average: 0.0973 µgm-3 and K (range : n.d. – 301.15 µgm-3; average: 0.0535 µgm-3 were emitted from welding activity, and thus are considered as components of welding fume which contribute to urban air pollution. Although welding fume and the identified species in welding fume were still below permissible limit, small-scale welding activities have great potential in emitting higher fume concentration due to due to high variability of welding activities, such as welding frequency, materials being welded, and varied environmental conditions

Determination of Informal Sector as Urban Pollution Source : Fume Characterization of Small-scale Manual Metal Arc Welding using Factor Analysis in Bandung City

International Nuclear Information System (INIS)

Nastiti, A.; Pramudyastuti, D.Y.; Oginawati, K.; Santoso, M.

2012-01-01

In developing countries, the informal sector, particularly small-scale welding activities, are considered to be an important contributor to urban air pollution although studies in this sector are limited. This study aims to identify the composition of small-scale welding fume in order to further investigate the effects and set control strategies and urban pollution abatement policies. Breathing zone air samples were collected from 30 mild steel manual metal arc welders and 17 non-welders in Bandung City, West Java, Indonesia. The respirable particulates in air samples were analyzed using gravimetric method, and Instrumental Neutron Activation Analysis (INAA) was employed to identify characteristic of welding fume. It was found that respirable particulates concentration in welders (range : 315.6 and 3,735.93 µgm -3 ; average 1,545.436 µgm -3 ) were significantly higher than in non-welders (range : 41.84 and 1,688.03 µgm -3 ; average : 375.783 µgm -3 ). Welders' breathing zones contain Fe>Na>K>Mn>Al >Cr>Ti>Cl>Br>I>Zn>Sb>V>Co>Sc; while non-welders' breathing zones contain Cr>F>Al>Ti>Na>Br>I>Mn>Cl>Co>Zn>Sc. Inter-species correlation analysis conducted using Statgraphic Ver. 4.0 shows that Fe (range : n.d. - 775.19 µgm -3 ; average: 0.1674µgm -3 ), Co (range : n.d. - 0.51 µgm -3 ; average: 0.000082 µgm -3 ), Mn (range : 0.39 - 148.37 µgm -3 ; average: 0.0374 µgm -3 ), Na (range: 0.17 and 623.85 µgm -3 ; average: 0.0973 µgm -3 ) and K (range : n.d. - 301.15 µgm -3 ; average: 0.0535 µgm -3 ) were emitted from welding activity, and thus are considered as components of welding fume which contribute to urban air pollution. Although welding fume and the identified species in welding fume were still below permissible limit, small-scale welding activities have great potential in emitting higher fume concentration due to due to high variability of welding activities, such as welding frequency, materials being welded, and varied environmental conditions. (author)

A model for prediction of fume formation rate in gas metal arc welding (GMAW), globular and spray modes, DC electrode positive.

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Dennis, J H; Hewitt, P J; Redding, C A; Workman, A D

2001-03-01

Prediction of fume formation rate during metal arc welding and the composition of the fume are of interest to occupational hygienists concerned with risk assessment and to manufacturers of welding consumables. A model for GMAW (DC electrode positive) is described based on the welder determined process parameters (current, wire feed rate and wire composition), on the surface area of molten metal in the arc and on the partial vapour pressures of the component metals of the alloy wire. The model is applicable to globular and spray welding transfer modes but not to dip mode. Metal evaporation from a droplet is evaluated for short time increments and total evaporation obtained by summation over the life of the droplet. The contribution of fume derived from the weld pool and spatter (particles of metal ejected from the arc) is discussed, as are limitations of the model. Calculated droplet temperatures are similar to values determined by other workers. A degree of relationship between predicted and measured fume formation rates is demonstrated but the model does not at this stage provide a reliable predictive tool.

Manganese in exhaled breath condensate: a new marker of exposure to welding fumes.

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Hulo, Sébastien; Chérot-Kornobis, Nathalie; Howsam, Mike; Crucq, Sébastien; de Broucker, Virginie; Sobaszek, Annie; Edme, Jean-Louis

2014-04-07

To evaluate manganese in exhaled breath condensate (Mn-EBC) as an indicator of exposure to fumes from metal inert gas welding process. We collected EBC and urine from 17 welders and 16 unexposed control subjects after 5 days exposure. Concentrations of manganese (Mn), nickel (Ni), iron (Fe) and chromium (Cr) were measured in EBC and urine samples and correlated with cumulative exposure indices for the working week (CIW) and for the total welding years (WY), based on duration of welding activity and atmospheric metal measurements. Concentrations of Mn and Ni in EBC were significantly higher among welders than controls whereas this difference was not significant for Mn in urine. Levels of Mn and Ni in EBC were not correlated with their respective levels in urine. The linear regressions found significant positive coefficients between Mn-EBC, Ni-EBC, Ni-U and Cr-U concentrations and the cumulative exposure indices. Taking into account tobacco use, statistical analysis showed the same trends except for the relationship between Mn-U and CIW. This pilot study showed that Mn-EBC, as well as Ni-EBC, can serve as reliable indices of occupational exposure to welding fumes and provide complimentary toxicokinetic information to that provided by urine analyses. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

A comparison of cytotoxicity and oxidative stress from welding fumes generated with a new nickel-, copper-based consumable versus mild and stainless steel-based welding in RAW 264.7 mouse macrophages.

Science.gov (United States)

Badding, Melissa A; Fix, Natalie R; Antonini, James M; Leonard, Stephen S

2014-01-01

Welding processes that generate fumes containing toxic metals, such as hexavalent chromium (Cr(VI)), manganese (Mn), and nickel (Ni), have been implicated in lung injury, inflammation, and lung tumor promotion in animal models. While federal regulations have reduced permissible worker exposure limits to Cr(VI), this is not always practical considering that welders may work in confined spaces and exhaust ventilation may be ineffective. Thus, there has been a recent initiative to minimize the potentially hazardous components in welding materials by developing new consumables containing much less Cr(VI) and Mn. A new nickel (Ni) and copper (Cu)-based material (Ni-Cu WF) is being suggested as a safer alternative to stainless steel consumables; however, its adverse cellular effects have not been studied. This study compared the cytotoxic effects of the newly developed Ni-Cu WF with two well-characterized welding fumes, collected from gas metal arc welding using mild steel (GMA-MS) or stainless steel (GMA-SS) electrodes. RAW 264.7 mouse macrophages were exposed to the three welding fumes at two doses (50 µg/ml and 250 µg/ml) for up to 24 hours. Cell viability, reactive oxygen species (ROS) production, phagocytic function, and cytokine production were examined. The GMA-MS and GMA-SS samples were found to be more reactive in terms of ROS production compared to the Ni-Cu WF. However, the fumes from this new material were more cytotoxic, inducing cell death and mitochondrial dysfunction at a lower dose. Additionally, pre-treatment with Ni-Cu WF particles impaired the ability of cells to phagocytize E. coli, suggesting macrophage dysfunction. Thus, the toxic cellular responses to welding fumes are largely due to the metal composition. The results also suggest that reducing Cr(VI) and Mn in the generated fume by increasing the concentration of other metals (e.g., Ni, Cu) may not necessarily improve welder safety.

Evaluation of the Pulmonary Toxicity of a Fume Generated from a Nickel-, Copper-Based Electrode to be Used as a Substitute in Stainless Steel Welding

Science.gov (United States)

Antonini, James M; Badding, Melissa A; Meighan, Terence G; Keane, Michael; Leonard, Stephen S; Roberts, Jenny R

2014-01-01

Epidemiology has indicated a possible increase in lung cancer among stainless steel welders. Chromium (Cr) is a primary component of stainless steel welding fume. There is an initiative to develop alternative welding consumables [nickel (Ni)- and copper (Cu)-based alloys] that do not contain Cr. No study has been performed to evaluate the toxicity of fumes generated from Ni- and Cu-based consumables. Dose–response and time-course effects on lung toxicity of a Ni- and Cu-based welding fume (Ni–Cu WF) were examined using an in vivo and in vitro bioassay, and compared with two other well-characterized welding fumes. Even though only trace amounts of Cr were present, a persistent increase in lung injury and inflammation was observed for the Ni–Cu WF compared to the other fumes. The difference in response appears to be due to a direct cytotoxic effect by the Ni–Cu WF sample on lung macrophages as opposed to an elevated production of reactive oxygen species (ROS). PMID:25392698

Human biomonitoring of chromium and nickel from an experimental exposure to manual metal arc welding fumes of low and high alloyed steel.

Science.gov (United States)

Bertram, Jens; Brand, Peter; Schettgen, Thomas; Lenz, Klaus; Purrio, Ellwyn; Reisgen, Uwe; Kraus, Thomas

2015-05-01

The uptake and elimination of metals from welding fumes is currently not fully understood. In the Aachen Workplace Simulation Laboratory (AWSL) it is possible to investigate the impact of welding fumes on human subjects under controlled exposure conditions. In this study, the uptake and elimination of chromium or chromium (VI) respectively as well as nickel was studied in subjects after exposure to the emissions of a manual metal arc welding process using low or high alloyed steel. In this present study 12 healthy male non-smokers, who never worked as welders before, were exposed for 6h to welding fumes of a manual metal arc welding process. In a three-fold crossover study design, subjects were exposed in randomized order to either clean air, emissions from welding low alloyed steel, and emissions from welding high alloyed steel. Particle mass concentration of the exposure aerosol was 2.5mg m(-3). The content of chromium and nickel in the air was determined by analysing air filter samples on a high emission scenario. Urine analysis for chromium and nickel was performed before and after exposure using methods of human biomonitoring. There were significantly elevated chromium levels after exposure to welding fumes from high alloyed steel compared to urinary chromium levels before exposure to high alloyed welding fumes, as well as compared to the other exposure scenarios. The mean values increased from 0.27 µg l(-1) to 18.62 µg l(-1). The results were in good agreement with already existing correlations between external and internal exposure (German exposure equivalent for carcinogenic working materials EKA). The variability of urinary chromium levels was high. For urinary nickel no significant changes could be detected at all. Six-hour exposure to 2.5mg m(-3) high alloyed manual metal arc welding fumes lead to elevated urinary chromium levels far higher (7.11-34.16 µg l(-1)) than the German biological exposure reference value (BAR) of 0.6 µg l(-1) directly after

Parental Occupational Exposure to Heavy Metals and Welding Fumes and Risk of Testicular Germ Cell Tumors in Offspring

DEFF Research Database (Denmark)

Togawa, Kayo; Le Cornet, Charlotte; Feychting, Maria

2016-01-01

BACKGROUND: Data are scarce on the association between prenatal/preconception environmental exposure and testicular germ cell tumor (TGCT) in offspring. We examined parental occupational exposures to heavy metals and welding fumes in relation to TGCT in offspring in a registry-based case-control ......BACKGROUND: Data are scarce on the association between prenatal/preconception environmental exposure and testicular germ cell tumor (TGCT) in offspring. We examined parental occupational exposures to heavy metals and welding fumes in relation to TGCT in offspring in a registry-based case......-control study (NORD-TEST Study). METHODS: We identified TGCT cases diagnosed at ages 14-49 years in Finland (1988-2012), Norway (1978-2010), and Sweden (1979-2011) through nationwide cancer registries. These cases were individually matched by country and year of birth to controls selected from population...... registries. Information on parental occupations was retrieved from censuses. From this, we estimated prenatal/preconception exposures of chromium, iron, nickel, lead, and welding fumes (all three countries), and cadmium (Finland only) for each parent using job-exposure matrices specifying prevalence (P...

Occupational exposure to solvents, metals and welding fumes and risk of Parkinson's disease

NARCIS (Netherlands)

van der Mark, Marianne; Vermeulen, Roel; Nijssen, Peter C G; Mulleners, Wim M; Sas, Antonetta M G; van Laar, Teus; Huss, Anke; Kromhout, Hans

OBJECTIVES: The aim of this study was to investigate the potential association between occupational exposure to solvents, metals and/or welding fumes and risk of developing Parkinson's disease (PD). METHODS: Data of a hospital based case-control study including 444 PD patients and 876 age and sex

Biomarkers of exposure to stainless steel tungsten inert gas welding fumes and the effect of exposure on exhaled breath condensate.

Science.gov (United States)

Riccelli, Maria Grazia; Goldoni, Matteo; Andreoli, Roberta; Mozzoni, Paola; Pinelli, Silvana; Alinovi, Rossella; Selis, Luisella; Mutti, Antonio; Corradi, Massimo

2018-08-01

The respiratory tract is the main target organ of the inhaled hexavalent chromium (Cr-VI) and nickel (Ni) contained in stainless steel (SS) welding fumes (WFs). The aim of this study was to investigate the Cr and Ni content of the exhaled breath condensate (EBC) of SS tungsten inert gas (TIG) welders, and relate their concentrations with oxidative stress and inflammatory biomarkers. EBC and urine from 100 SS TIG welders were collected pre-(T 0 ) and post-shift (T 1 ) on a Friday, and pre-shift (T 2 ) on the following Monday morning. Both EBC and urinary Cr concentrations were higher at T 1 (0.08 μg/L and 0.71 μg/g creatinine) and T 0 (0.06 μg/L and 0.74 μg/g creatinine) than at T 2 (below the limit of detection [LOD] and 0.59 μg/g creatinine), and EBC Ni concentrations generally remained welding also play a role in generating lung oxidative stress. Copyright © 2018 Elsevier B.V. All rights reserved.

Altered ion transport in normal human bronchial epithelial cells following exposure to chemically distinct metal welding fume particles.

Science.gov (United States)

Fedan, Jeffrey S; Thompson, Janet A; Meighan, Terence G; Zeidler-Erdely, Patti C; Antonini, James M

2017-07-01

Welding fume inhalation causes pulmonary toxicity, including susceptibility to infection. We hypothesized that airway epithelial ion transport is a target of fume toxicity, and investigated the effects of fume particulates from manual metal arc-stainless steel (MMA-SS) and gas metal arc-mild steel (GMA-MS) on ion transport in normal human bronchial epithelium (NHBE) cultured in air-interface. MMA-SS particles, more soluble than GMA-MS particles, contain Cr, Ni, Fe and Mn; GMA-MS particles contain Fe and Mn. MMA-SS or GMA-MS particles (0.0167-166.7μg/cm 2 ) were applied apically to NHBEs. After 18h transepithelial potential difference (V t ), resistance (R t ), and short circuit current (I sc ) were measured. Particle effects on Na + and Cl¯ channels and the Na + ,K + ,2Cl¯-cotransporter were evaluated using amiloride (apical), 5-nitro-2-[(3-phenylpropyl)amino]benzoic acid (NPPB, apical), and bumetanide (basolateral), respectively. MMA-SS (0.0167-16.7μg/cm 2 ) increased basal V t . Only 16.7μg/cm 2 GMA-MS increased basal V t significantly. MMA-SS or GMA-MS exposure potentiated I sc responses (decreases) to amiloride and bumetanide, while not affecting those to NPPB, GMA-MS to a lesser degree than MMA-SS. Variable effects on R t were observed in response to amiloride, and bumetanide. Generally, MMA-SS was more potent in altering responses to amiloride and bumetanide than GMA-MS. Hyperpolarization occurred in the absence of LDH release, but decreases in V t , R t , and I sc at higher fume particulate doses accompanied LDH release, to a greater extent for MMA-SS. Thus, Na + transport and Na + ,K + ,2Cl¯-cotransport are affected by fume exposure; MMA-MS is more potent than GMA-MS. Enhanced Na + absorption and decreased airway surface liquid could compromise defenses against infection. Published by Elsevier Inc.

A Cross-Sectional Study of the Cardiovascular Effects of Welding Fumes.

Directory of Open Access Journals (Sweden)

Huiqi Li

Full Text Available Occupational exposure to particulate air pollution has been associated with an increased risk of cardiovascular disease. However, the risk to welders working today remains unclear. We aimed to elucidate the cardiovascular effects of exposure to welding fumes.In a cross-sectional study, structured interviews and biological sampling were conducted for 101 welders and 127 controls (all non-smoking males from southern Sweden. Personal breathing zone sampling of respirable dust was performed. Blood pressure (BP and endothelial function (using peripheral arterial tonometry were measured. Plasma and serum samples were collected from peripheral blood for measurement of C-reactive protein, low-density lipoprotein, homocysteine, serum amyloid A, and cytokines.Welders were exposed to 10-fold higher levels of particles than controls. Welders had significantly higher BP compared to controls, an average of 5 mm Hg higher systolic and diastolic BP (P ≤ 0.001. IL-8 was 3.4 ng/L higher in welders (P=0.010. Years working as a welder were significantly associated with increased BP (β=0.35, 95%CI 0.13 - 0.58, P=0.0024 for systolic BP; β=0.32, 95%CI 0.16 - 0.48, P<0.001 for diastolic BP, adjusted for BMI but exposure to respirable dust was not associated with BP. No clear associations occurred between welding and endothelial function, or other effect markers.A modest increase in BP was found among welders compared to controls suggesting that low-to-moderate exposure to welding fumes remains a risk factor for cardiovascular disease.

Exposure to welding fumes is associated with hypomethylation of the F2RL3 gene: a cardiovascular disease marker.

Science.gov (United States)

Hossain, Mohammad B; Li, Huiqi; Hedmer, Maria; Tinnerberg, Håkan; Albin, Maria; Broberg, Karin

2015-12-01

Welders are at risk for cardiovascular disease. Recent studies linked tobacco smoke exposure to hypomethylation of the F2RL3 (coagulation factor II (thrombin) receptor-like 3) gene, a marker for cardiovascular disease prognosis and mortality. However, whether welding fumes cause hypomethylation of F2RL3 remains unknown. We investigated 101 welders (median span of working as a welder: 7 years) and 127 unexposed controls (non-welders with no obvious exposure to respirable dust at work), age range 23-60 years, all currently non-smoking, in Sweden. The participants were interviewed about their work history, lifestyle factors and diseases. Personal sampling of respirable dust was performed for the welders. DNA methylation of F2RL3 in blood was assessed by pyrosequencing of four CpG sites, CpG_2 (corresponds to cg03636183) to CpG_5, in F2RL3. Multivariable linear regression analysis was used to assess the association between exposure to welding fumes and F2RL3 methylation. Welders had 2.6% lower methylation of CpG_5 than controls (pWelding fumes exposure and previous smoking were associated with F2RL3 hypomethylation. This finding links low-to-moderate exposure to welding fumes to adverse effects on the cardiovascular system, and suggests a potential mechanistic pathway for this link, via epigenetic effects on F2RL3 expression. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Systemic immune cell response in rats after pulmonary exposure to manganese-containing particles collected from welding aerosols.

Science.gov (United States)

Antonini, James M; Zeidler-Erdely, Patti C; Young, Shih-Houng; Roberts, Jenny R; Erdely, Aaron

2012-01-01

Welding fume inhalation affects the immune system of exposed workers. Manganese (Mn) in welding fume may induce immunosuppressive effects. The goal was to determine if Mn in welding fume alters immunity by reducing the number of circulating total leukocytes and specific leukocyte sub-populations. Sprague-Dawley rats were treated by intratracheal instillation (ITI) with either a single dose (2.00 mg/rat) or repeated doses (0.125 or 2.00 mg/rat for 7 weeks) with welding fumes that contained different levels of Mn. Additional rats were treated by ITI once a week for 7 weeks with the two doses of manganese chloride (MnCl₂). Bronchoalveolar lavage was performed to assess lung inflammation. Also, whole blood was recovered, and the number of circulating total leukocytes, as well as specific lymphocyte subsets, was determined by flow cytometry. The welding fume highest in Mn content significantly increased lung inflammation, injury, and production of inflammatory cytokines and chemokines compared to all other treatment groups. In addition, the same group expressed significant decreases in the number of circulating CD4⁺ and CD8⁺ T-lymphocytes after a single exposure, and significant reductions in the number of circulating total lymphocytes, primarily CD4⁺ and CD8⁺ T-lymphocytes, after repeated exposures (compared to control values). Repeated MnCl₂ exposure led to a trend of a reduction (but not statistically significant) in circulating total lymphocytes, attributable to the changes in the CD4⁺ T-lymphocyte population levels. The welding fume with the lower concentration of Mn had no significant effect on the numbers of blood lymphocytes and lymphocyte subsets compared to control values. Evidence from this study indicates that pulmonary exposure to certain welding fumes cause decrements in systemic immune cell populations, specifically circulating T-lymphocytes, and these alterations in immune cell number are not dependent exclusively on Mn, but likely a

Personal exposure to metal fume, NO2, and O3 among production welders and non-welders.

Science.gov (United States)

Schoonover, Todd; Conroy, Lorraine; Lacey, Steven; Plavka, Julie

2011-01-01

The objective of this study was to characterize personal exposures to welding-related metals and gases for production welders and non-welders in a large manufacturing facility. Welding fume metals and irritant gases nitrogen dioxide (NO(2)) and ozone (O(3)) were sampled for thirty-eight workers. Personal exposure air samples for welding fume metals were collected on 37 mm open face cassettes and nitrogen dioxide and ozone exposure samples were collected with diffusive passive samplers. Samples were analyzed for metals using Inductively Coupled Plasma Mass Spectrometry (ICP-MS) and welding fume metal exposure concentrations were defined as the sum of welding-related metals mass per volume of air sampled. Welding fume metal exposures were highly variable among similar types of welding while NO(2) and O(3) exposure were less variable. Welding fume metal exposures were significantly higher 474 μg/m(3) for welders than non-welders 60 μg/m(3) (p=0.001). Welders were exposed to higher concentrations of NO(2) and O(3) than non-welders but the differences were not statistically significant. Welding fume metal exposure concentrations for welders performing gas metal arc welding (GMAW) and shielded metal arc welding (SMAW) were higher than welders performing gas tungsten arc welding (GTAW). Non-welders experienced exposures similar to GTAW welders despite a curtain wall barrier separating welding and non-welding work areas.

Exposure to welding fumes and lower airway infection with Streptococcus pneumoniae.

Science.gov (United States)

Suri, Reetika; Periselneris, Jimstan; Lanone, Sophie; Zeidler-Erdely, Patti C; Melton, Geoffrey; Palmer, Keith T; Andujar, Pascal; Antonini, James M; Cohignac, Vanessa; Erdely, Aaron; Jose, Ricardo J; Mudway, Ian; Brown, Jeremy; Grigg, Jonathan

2016-02-01

Welders are at increased risk of pneumococcal pneumonia. The mechanism for this association is not known. The capacity of pneumococci to adhere to and infect lower airway cells is mediated by host-expressed platelet-activating factor receptor (PAFR). We sought to assess the effect of mild steel welding fumes (MS-WF) on PAFR-dependent pneumococcal adhesion and infection to human airway cells in vitro and on pneumococcal airway infection in a mouse model. The oxidative potential of MS-WF was assessed by their capacity to reduce antioxidants in vitro. Pneumococcal adhesion and infection of A549, BEAS-2B, and primary human bronchial airway cells were assessed by means of quantitative bacterial culture and expressed as colony-forming units (CFU). After intranasal instillation of MS-WF, mice were infected with Streptococcus pneumoniae, and bronchoalveolar lavage fluid (BALF) and lung CFU values were determined. PAFR protein levels were assessed by using immunofluorescence and immunohistochemistry, and PAFR mRNA expression was assessed by using quantitative PCR. PAFR was blocked by CV-3988, and oxidative stress was attenuated by N-acetylcysteine. MS-WF exhibited high oxidative potential. In A549 and BEAS-2B cells MS-WF increased pneumococcal adhesion and infection and PAFR protein expression. Both CV-3988 and N-acetylcysteine reduced MS-WF-stimulated pneumococcal adhesion and infection of airway cells. MS-WF increased mouse lung PAFR mRNA expression and increased BALF and lung pneumococcal CFU values. In MS-WF-exposed mice CV-3988 reduced BALF CFU values. Hypersusceptibility of welders to pneumococcal pneumonia is in part mediated by the capacity of welding fumes to increase PAFR-dependent pneumococcal adhesion and infection of lower airway cells. Copyright © 2015 American Academy of Allergy, Asthma & Immunology. All rights reserved.

A Field Study on the Respiratory Deposition of the Nano-Sized Fraction of Mild and Stainless Steel Welding Fume Metals.

Science.gov (United States)

Cena, L G; Chisholm, W P; Keane, M J; Chen, B T

2015-01-01

A field study was conducted to estimate the amount of Cr, Mn, and Ni deposited in the respiratory system of 44 welders in two facilities. Each worker wore a nanoparticle respiratory deposition (NRD) sampler during gas metal arc welding (GMAW) of mild and stainless steel and flux-cored arc welding (FCAW) of mild steel. Several welders also wore side-by-side NRD samplers and closed-face filter cassettes for total particulate samples. The NRD sampler estimates the aerosol's nano-fraction deposited in the respiratory system. Mn concentrations for both welding processes ranged 2.8-199 μg/m3; Ni concentrations ranged 10-51 μg/m3; and Cr concentrations ranged 40-105 μg/m3. Cr(VI) concentrations ranged between 0.5-1.3 μg/m3. For the FCAW process the largest concentrations were reported for welders working in pairs. As a consequence this often resulted in workers being exposed to their own welding fumes and to those generated from the welding partner. Overall no correlation was found between air velocity and exposure (R2 = 0.002). The estimated percentage of the nano-fraction of Mn deposited in a mild-steel-welder's respiratory system ranged between 10 and 56%. For stainless steel welding, the NRD samplers collected 59% of the total Mn, 90% of the total Cr, and 64% of the total Ni. These results indicate that most of the Cr and more than half of the Ni and Mn in the fumes were in the fraction smaller than 300 nm.

Lifetime occupational exposure to metals and welding fumes, and risk of glioma: a 7-country population-based case-control study.

Science.gov (United States)

Parent, Marie-Elise; Turner, Michelle C; Lavoué, Jérôme; Richard, Hugues; Figuerola, Jordi; Kincl, Laurel; Richardson, Lesley; Benke, Geza; Blettner, Maria; Fleming, Sarah; Hours, Martine; Krewski, Daniel; McLean, David; Sadetzki, Siegal; Schlaefer, Klaus; Schlehofer, Brigitte; Schüz, Joachim; Siemiatycki, Jack; van Tongeren, Martie; Cardis, Elisabeth

2017-08-25

Brain tumor etiology is poorly understood. Based on their ability to pass through the blood-brain barrier, it has been hypothesized that exposure to metals may increase the risk of brain cancer. Results from the few epidemiological studies on this issue are limited and inconsistent. We investigated the relationship between glioma risk and occupational exposure to five metals - lead, cadmium, nickel, chromium and iron- as well as to welding fumes, using data from the seven-country INTEROCC study. A total of 1800 incident glioma cases and 5160 controls aged 30-69 years were included in the analysis. Lifetime occupational exposure to the agents was assessed using the INTEROCC JEM, a modified version of the Finnish job exposure matrix FINJEM. In general, cases had a slightly higher prevalence of exposure to the various metals and welding fumes than did controls, with the prevalence among ever exposed ranging between 1.7 and 2.2% for cadmium to 10.2 and 13.6% for iron among controls and cases, respectively. However, in multivariable logistic regression analyses, there was no association between ever exposure to any of the agents and risk of glioma with odds ratios (95% confidence intervals) ranging from 0.8 (0.7-1.0) for lead to 1.1 (0.7-1.6) for cadmium. Results were consistent across models considering cumulative exposure or duration, as well as in all sensitivity analyses conducted. Findings from this large-scale international study provide no evidence for an association between occupational exposure to any of the metals under scrutiny or welding fumes, and risk of glioma.

Hepatotoxic and Nephrotoxic Effects of Petroleum Fumes on Petrol ...

African Journals Online (AJOL)

DR SULEIMAN

Hepatotoxic and Nephrotoxic Effects of Petroleum Fumes on Petrol Attendants in Ibadan, Nigeria. *1A.L. Ogunneye ... inhalation of petrol fumes is associated with adverse effect on the kidney and liver function. ..... neurotoxicity in mice. African ...

Peripheral neuropathy following intentional inhalation of naphtha fumes.

Science.gov (United States)

Tenenbein, M; deGroot, W; Rajani, K R

1984-01-01

Two adolescent native Canadians who presented with peripheral neuropathy secondary to the abuse of volatile hydrocarbons are described. They were initially thought to have been sniffing leaded gasoline fumes, but public health investigation revealed that they had been sniffing naphtha fumes. Naphtha contains a significant amount of n-hexane, a known inducer of neuropathy. Nerve conduction studies and nerve biopsy confirmed the diagnosis of naphtha abuse. These cases emphasize the need to specifically identify the formulation of hydrocarbons being abused. PMID:6093978

A mini-sampler for welding aerosol mounted in close vicinity of the mouth/nose

International Nuclear Information System (INIS)

Liden, Goeran; Surakka, Jouni

2009-01-01

A small personal aerosol mini-sampler to be used inside modern welding visors has been developed. The main object of the mini-sampler has been to sample manganese. The sampler is based on commercially available 13 mm filter holders but modified to incorporate an inlet nozzle made of aluminium. The nominal flow rate of the mini-sampler is 0,75 l/min. The sampler is to be worn mounted on a headset, modified from professional microphone headsets. The headset mounting arrangement was accepted by the welders. The sampling bias of the mini sampler versus the IOM sampler depends on the coarseness of the sampled aerosol. At the lowest concentration ratio of the open-face 25 mm filter holder to the IOM sampler equal to 0,65, the bias of the mini sampler is approximately -26% versus the IOM. The RMS sampling bias of the mini sampler versus the IOM sampler for manganese is -4,6%. The inhalable fraction of welding aerosol mass consists only of 25-55% of welding fume. The rest of the mass is made up of spatter particles and grinding particles. For manganese generally more than 65% is found in the fume.

[New welding processes and health effects of welding].

Science.gov (United States)

La Vecchia, G Marina; Maestrelli, Piero

2011-01-01

This paper describes some of the recent developments in the control technology to enhance capability of Pulse Gas Metal Arc Welding. Friction Stir Welding (FSW) processing has been also considered. FSW is a new solid-state joining technique. Heat generated by friction at the rotating tool softens the material being welded. FSW can be considered a green and energy-efficient technique without deleterious fumes, gas, radiation, and noise. Application of new welding processes is limited and studies on health effects in exposed workers are lacking. Acute and chronic health effects of conventional welding have been described. Metal fume fever and cross-shift decline of lung function are the main acute respiratory effects. Skin and eyes may be affected by heat, electricity and UV radiations. Chronic effects on respiratory system include chronic bronchitis, a benign pneumoconiosis (siderosis), asthma, and a possible increase in the incidence of lung cancer. Pulmonary infections are increased in terms of severity, duration, and frequency among welders.

Global metabolomic profiling reveals an association of metal fume exposure and plasma unsaturated fatty acids.

Directory of Open Access Journals (Sweden)

Yongyue Wei

Full Text Available Welding-associated air pollutants negatively affect the health of exposed workers; however, their molecular mechanisms in causing disease remain largely unclear. Few studies have systematically investigated the systemic toxic effects of welding fumes on humans.To explore the effects of welding fumes on the plasma metabolome, and to identify biomarkers for risk assessment of welding fume exposure.The two-stage, self-controlled exploratory study included 11 boilermakers from a 2011 discovery panel and 8 boilermakers from a 2012 validation panel. Plasma samples were collected pre- and post-welding fume exposure and analyzed by chromatography/mass spectrometry.Eicosapentaenoic or docosapentaenoic acid metabolic changes post-welding were significantly associated with particulate (PM2.5 exposure (p<0.05. The combined analysis by linear mixed-effects model showed that exposure was associated with a statistically significant decline in metabolite change of eicosapentaenoic acid [β(95% CI = -0.013(-0.022 ≈ -0.004; p = 0.005], docosapentaenoic acid n3 [β(95% CI = -0.010(-0.018 ≈ -0.002; p = 0.017], and docosapentaenoic acid n6 [β(95% CI = -0.007(-0.013 ≈ -0.001; p = 0.021]. Pathway analysis identified an association of the unsaturated fatty acid pathway with exposure (p Study-2011 = 0.025; p Study-2012 = 0.021; p Combined = 0.009. The functional network built by these fatty acids and their interactive genes contained significant enrichment of genes associated with various diseases, including neoplasms, cardiovascular diseases, and lipid metabolism disorders.High-dose exposure of metal welding fumes decreases unsaturated fatty acids with an exposure-response relationship. This alteration in fatty acids is a potential biological mediator and biomarker for exposure-related health disorders.

Methanol toxicity secondary to inhalant abuse in adult men.

Science.gov (United States)

Wallace, Erik A; Green, Adam S

2009-03-01

The purpose of this report is to evaluate the presentation, treatment, and outcomes of adults with methanol toxicity from inhalation of carburetor cleaning fluid fumes. Retrospective chart review of adults with positive serum volatile screen for methanol and history of carburetor cleaning fluid fume inhalation. Sixteen patients were admitted 68 times. Eleven Native American patients accounted for 90% of admissions. Sixty-five cases presented with nausea/vomiting; 27 with intoxication or altered mental status; 21 with specific visual complaints. About 93% had a pH or=10 mOsm/L, and 69% had anion gap >16. Ten had an initial serum methanol level or=50 mg/dL. Six patients had a measurable serum ethanol level. Of the 29 patients with a methanol level of 20-49 mg/dL, 20 received intravenous antidote (ethanol or fomepizole); three received an antidote and hemodialysis. All who presented with a serum methanol level >or=50 mg/dL received intravenous ethanol or fomepizole. All visual symptoms resolved before discharge and all patients survived without sequelae. Discussion. This is the largest reported number of cases of methanol toxicity from the inhalation of carburetor cleaning fluid fumes and demonstrates a problem with recurrent abuse among some older Native American men. Intentional inhalation of methanol fumes may produce toxicity. Clinicians need to question patients, especially older Native American men, regarding the possible inhalation of carburetor cleaning fluid fumes in those who present with an unexplained metabolic anion gap acidosis.

Evaluation of occupational exposure to toxic metals released in the process of aluminum welding.

Science.gov (United States)

Matczak, Wanda; Gromiec, Jan

2002-04-01

The objective of this study was to evaluate occupational exposure to welding fumes and its elements on aluminum welders in Polish industry. The study included 52 MIG/Al fume samples and 18 TIG/Al samples in 3 plants. Air samples were collected in the breathing zone of welders (total and respirable dust). Dust concentration was determined gravimetrically, and the elements in the collected dust were determined by AAS. Mean time-weighted average (TWA) concentrations of the welding dusts/fumes and their components in the breathing zone obtained for different welding processes were, in mg/m3: MIG/Al fumes mean 6.0 (0.8-17.8), Al 2.1 (0.1-7.7), Mg 0.2 (TIG/Al fumes 0.7 (0.3-1.4), Al 0.17 (0.07-0.50). A correlation has been found between the concentration of the main components and the fume/dust concentrations in MIG/Al and TIG/Al fumes. Mean percentages of the individual components in MIG/Al fumes/dusts were Al: 30 (9-56) percent; Mg: 3 (1-5.6) percent; Mn: 0.2 (0.1-0.3) percent; Cu: 0.2 (welding methods, the nature of welding-related operations, and work environment conditions.

Acute Respiratory Distress Syndrome (ARDS After Nitric Acid Inhalation

Directory of Open Access Journals (Sweden)

Gülay Kır

2014-12-01

Full Text Available Lung injury resulting from inhalation of chemical products continues to be associated with high morbidity and mortality. Concentrated nitric acids are also extremely corrosive fuming chemical liquids. Fumes of nitric acid (HNO3 and various oxides of nitrogen such as nitric oxide (NO and nitrogen dioxide (NO2 may cause fatal illnesses such as severe pulmonary edema and acute respiratory distress syndrome (ARDS when inhaled. Intensive respiratory management including mechanical ventilation with positive end expiratory pressure (PEEP, inverse ratio ventilation, replacement of surfactant and extracorporeal membrane oxygenation (ECMO, steroids and n-acetylcysteine (NAC may improve survival. In this case report we present the diagnosis and successful treatment of a 57 years old male patient who developed ARDS following pulmonary edema due to nitric acid fumes inhalation.

Cardiovascular effects in rats after intratracheal instillation of metal welding particles.

Science.gov (United States)

Zheng, Wen; Antonini, James M; Lin, Yen-Chang; Roberts, Jenny R; Kashon, Michael L; Castranova, Vincent; Kan, Hong

2015-01-01

Studies have indicated that pulmonary exposure to welding fumes can induce a series of adverse effects in the respiratory system, including infection, bronchitis, siderosis and decreased pulmonary function. Recent clinical and epidemiological studies have found that pulmonary exposure to welding fumes is also associated with a higher incidence of cardiovascular events. However, there is insufficient evidence to confirm a direct effect of welding fumes on the cardiovascular system. The present study investigated the effects of pulmonary exposure to welding fumes on the heart and the vascular system in rats. Two chemically distinct welding fumes generated from manual metal arc-hard surfacing (MMA-HS) and gas metal arc-mild steel (GMA-MS) welding were tested. Three groups of rats were instilled intratracheally with MMA-HS (2 mg/rat), GMA-MS (2 mg/rat) or saline as control once a week for seven weeks. On days 1 and 7 after the last treatment, basal cardiovascular function and the cardiovascular response to increasing doses of adrenoreceptor agonists were assessed. MMA-HS treatment reduced the basal levels of left ventricle end-systolic pressure and dP/dt(max) at 1 day post-treatment, and decreased dP/dt(min) in response to isoproterenol (ISO) at 7 days post-treatment. Unlike MMA-HS, GMA-MS only affected left ventricular end-diastolic pressure in response to ISO at 7 days post-treatment. Treatment with MMA-HS or GMA-MS did not alter heart rate and blood pressure. Our findings suggest that exposure to different welding fumes can induce different adverse effects on the cardiovascular system, and that cardiac contractility may be a sensitive indicator of cardiovascular dysfunction.

Numerical analysis of the influence of particle charging on the fume formation process in arc welding

International Nuclear Information System (INIS)

Tashiro, Shinichi; Matsui, Sho; Tanaka, Manabu; Murphy, Anthony B

2013-01-01

In order to clarify the influence of electrostatic forces caused by charging of particles on the coagulation process in fume formation in arc welding, a previously developed fume formation model is modified to consider the influence of charging, for both local thermodynamic equilibrium (LTE) and non-LTE conditions. The model takes into account formation of the particles from metal vapour by nucleation, growth of the particles by condensation of metal vapour and coagulation of the particles by collisions to form secondary particles. Results are obtained for both ballistic and Brownian motion of the particles. It is found that the growth of secondary particles is suppressed when the average particle charge becomes significant, because charging of the particle hinders collisions among secondary particles through the strong repulsive electrostatic force. Furthermore, deviations from LTE strongly affect the coagulation process, because the increased electron density at a given gas temperature increases the charging of particles. Brownian motion leads to larger secondary particles, since the average particle speed is increased. The influence of Brownian motion and particle charging cancel each other to a large extent, particularly when deviations from LTE are considered. (paper)

Genotoxic Effects of Exposure to Gasoline Fumes on Petrol Pump Workers.

Science.gov (United States)

Shaikh, Amrin; Barot, Darshana; Chandel, Divya

2018-04-01

Petrol pump workers are occupationally exposed to gasoline and its fumes consisting of several mutagenic chemicals. To evaluate the genotoxic effects of exposure to gasoline fumes on petrol pump workers. The study groups included 70 petrol pump workers (exposed group) and 70 healthy age-matched individuals with no known exposure (comparison group). Buccal micronucleus cytome assay (BMCyt) was performed to check the genotoxicity caused due to inhalation of gasoline fumes. The frequencies of micronucleated cells, nuclear bud, condensed chromatin cells, karyorrhectic cells, pyknotic cells, and karyolytic cells were significantly higher in the exposed workers compared to the comparison group. Exposure to gasoline fumes is associated with increased frequency of cell abnormalities. This may lead to various health consequences including cancer in those occupationally exposed to gasoline fumes.

Genotoxic Effects of Exposure to Gasoline Fumes on Petrol Pump Workers

Directory of Open Access Journals (Sweden)

Amrin Shaikh

2018-04-01

Full Text Available Background: Petrol pump workers are occupationally exposed to gasoline and its fumes consisting of several mutagenic chemicals. Objective: To evaluate the genotoxic effects of exposure to gasoline fumes on petrol pump workers. Methods: The study groups included 70 petrol pump workers (exposed group and 70 healthy age-matched individuals with no known exposure (comparison group. Buccal micronucleus cytome assay (BMCyt was performed to check the genotoxicity caused due to inhalation of gasoline fumes. Results: The frequencies of micronucleated cells, nuclear bud, condensed chromatin cells, karyorrhectic cells, pyknotic cells, and karyolytic cells were significantly higher in the exposed workers compared to the comparison group. Conclusion: Exposure to gasoline fumes is associated with increased frequency of cell abnormalities. This may lead to various health consequences including cancer in those occupationally exposed to gasoline fumes.

Short term exposure to cooking fumes and pulmonary function

OpenAIRE

Qvenild Torgunn; Svendsen Kristin; Svedahl Sindre; Sjaastad Ann; Hilt Bjørn

2009-01-01

Abstract Background Exposure to cooking fumes may have different deleterious effects on the respiratory system. The aim of this study was to look at possible effects from inhalation of cooking fumes on pulmonary function. Methods Two groups of 12 healthy volunteers (A and B) stayed in a model kitchen for two and four hours respectively, and were monitored with spirometry four times during twenty four hours, on one occasion without any exposure, and on another with exposure to controlled level...

Genotoxic Effects of Exposure to Gasoline Fumes on Petrol Pump Workers

OpenAIRE

Amrin Shaikh; Darshana Barot; Divya Chandel

2018-01-01

Background: Petrol pump workers are occupationally exposed to gasoline and its fumes consisting of several mutagenic chemicals. Objective: To evaluate the genotoxic effects of exposure to gasoline fumes on petrol pump workers. Methods: The study groups included 70 petrol pump workers (exposed group) and 70 healthy age-matched individuals with no known exposure (comparison group). Buccal micronucleus cytome assay (BMCyt) was performed to check the genotoxicity caused due to inhalation ...

Experimental exposure of healthy subjects with emissions from a gas metal arc welding process--part II: biomonitoring of chromium and nickel.

Science.gov (United States)

Gube, Monika; Brand, Peter; Schettgen, Thomas; Bertram, Jens; Gerards, Kerstin; Reisgen, Uwe; Kraus, Thomas

2013-01-01

The objective of this study was to investigate whether there is a relationship between the external exposure dose of chromium and nickel caused by a metal active gas welding process with a solid high-alloyed steel welding wire and inner exposure of subjects. In order to perform welding fume exposure under controlled and standardized conditions, the investigations were conducted in the "Aachen Workplace Simulation Laboratory". To perform biological monitoring of chromium and nickel, blood and urine samples of 12 healthy male non-smokers who never worked as welders were collected before and after a 6-h exposure to ambient air (0 mg/m(3)) and to welding fumes of a metal active gas welding process once with a concentration of the welding fume of 1 mg/m(3) and once with a concentration of 2.5 mg/m(3). Although the internal exposure to chromium and nickel in this study was comparatively low, the subjects showed significantly increased concentrations of these metals in urine after exposure to welding fume compared to the values at baseline. Moreover, the observed increase was significantly dose dependent for both of the substances. For the biological monitoring of chromium and nickel in urine of subjects exposed to welding fumes, a dependency on exposure dose was seen under standardized conditions after a single exposure over a period of 6 h. Thus, this study contributes to a better understanding of the relationship between ambient and biological exposures from welding fumes and provides a good basis for evaluating future biological threshold values for these metals in welding occupation.

Exposure of healthy subjects with emissions from a gas metal arc welding process: part 1--exposure technique and external exposure.

Science.gov (United States)

Brand, P; Havlicek, P; Steiners, M; Holzinger, K; Reisgen, U; Kraus, T; Gube, M

2013-01-01

Studies concerning welding fume-related adverse health effects in welders are hampered by the heterogeneity of workplace situations, resulting in complex and non-standardized exposure conditions. In order to carry out welding fume exposure studies under controlled and standardized conditions, the Aachen Workplace Simulation Laboratory was developed. This laboratory consists of an emission room, in which welding fume is produced, and an exposure room in which human subjects are exposed to these fumes. Both rooms are connected by a ventilation system which allows the welding fume concentration to be regulated. Particle mass concentration was measured with a TEOM microbalance and the particle number-size distribution using a Grimm SMPS device. In a study, which is the subject of this paper, it has been shown that welding fume concentration can easily be regulated between 1 and about 3 mg m(-3). The chosen concentration can be kept constant for more than 8 h. However, transport of the particles from the emission room into the exposure room leads to a change in particle size distribution, which is probably due to coagulation of the fraction of smallest particles. The Aachen Workplace Simulation Laboratory is suitable for controlled exposure studies with human subjects.

Oxidative stress, telomere shortening, and DNA methylation in relation to low-to-moderate occupational exposure to welding fumes.

Science.gov (United States)

Li, Huiqi; Hedmer, Maria; Wojdacz, Tomasz; Hossain, Mohammad Bakhtiar; Lindh, Christian H; Tinnerberg, Håkan; Albin, Maria; Broberg, Karin

2015-10-01

Evidence suggests that exposure to welding fumes is a risk factor for lung cancer. We examined relationships between low-to-moderate occupational exposure to particles from welding fumes and cancer-related biomarkers for oxidative stress, changes in telomere length, and alterations in DNA methylation. We enrolled 101 welders and 127 controls (all currently nonsmoking men) from southern Sweden. We performed personal sampling of respirable dust and measured 8-oxodG concentrations in urine using a simplified liquid chromatography tandem mass spectrometry method. Telomere length in peripheral blood was measured by quantitative polymerase chain reaction. Methylation status of 10 tumor suppressor genes was determined by methylation-sensitive high-resolution melting analysis. All analyses were adjusted for age, body mass index, previous smoking, passive smoking, current residence, and wood burning stove/boiler at home. Welders were exposed to respirable dust at 1.2 mg/m(3) (standard deviation, 3.3 mg/m(3); range, 0.1-19.3), whereas control exposures did not exceed 0.1 mg/m(3) (P < 0.001). Welders and controls did not differ in 8-oxodG levels (β = 1.2, P = 0.17) or relative telomere length (β = -0.053, P = 0.083) in adjusted models. Welders showed higher probability of adenomatous polyposis coli (APC) methylation in the unadjusted model (odds ratio = 14, P = 0.014), but this was not significant in the fully adjusted model (P = 0.052). Every working year as a welder was associated with 0.0066 units shorter telomeres (95% confidence interval -0.013 to -0.00053, P = 0.033). Although there were no clear associations between concentrations of respirable dust and the biomarkers, there were modest signs of associations between oxidative stress, telomere alterations, DNA methylation, and occupational exposure to low-to-moderate levels of particles. © 2015 Wiley Periodicals, Inc.

Assessment of occupational exposure to manganese and other metals in welding fumes by portable X-ray fluorescence spectrometer.

Science.gov (United States)

Laohaudomchok, Wisanti; Cavallari, Jennifer M; Fang, Shona C; Lin, Xihong; Herrick, Robert F; Christiani, David C; Weisskopf, Marc G

2010-08-01

Elemental analysis of welding fume samples can be done using several laboratory-based techniques. However, portable measurement techniques could offer several advantages. In this study, we sought to determine whether the portable X-ray fluorescence spectrometer (XRF) is suitable for analysis of five metals (manganese, iron, zinc, copper, and chromium) on 37-mm polytetrafluoroethylene filters. Using this filter fitted on a cyclone in line with a personal pump, gravimetric samples were collected from a group of boilermakers exposed to welding fumes. We assessed the assumption of uniform deposition of these metals on the filters, and the relationships between measurement results of each metal obtained from traditional laboratory-based XRF and the portable XRF. For all five metals of interest, repeated measurements with the portable XRF at the same filter area showed good consistency (reliability ratios are equal or close to 1.0 for almost all metals). The portable XRF readings taken from three different areas of each filter were not significantly different (p-values = 0.77 to 0.98). This suggested that the metal rich PM(2.5) deposits uniformly on the samples collected using this gravimetric method. For comparison of the two XRFs, the results from the portable XRF were well correlated and highly predictive of those from the laboratory XRF. The Spearman correlation coefficients were from 0.325 for chromium, to 0.995 for manganese and 0.998 for iron. The mean differences as a percent of the mean laboratory XRF readings were also small (metals were moderately to strongly correlated with the total fine particle fraction on filters (Spearman rho = 0.41 for zinc to 0.97 for iron). Such strong correlations and comparable results suggested that the portable XRF could be used as an effective and reliable tool for exposure assessment in many studies.

Cow Dung Ingestion and Inhalation Dependence: A Case Report

Science.gov (United States)

Khairkar, Praveen; Tiple, Prashant; Bang, Govind

2009-01-01

Although abuse of several unusual inhalants had been documented, addiction to cow dung fumes or their ashes has not been reported in medical literature as yet. We are reporting a case of cow dung dependence in ingestion and inhalational form.

Toenail as Non-invasive Biomarker in Metal Toxicity Measurement of Welding Fumes Exposure - A Review

Science.gov (United States)

Bakri, S. F. Z.; Hariri, A.; Ma'arop, N. F.; Hussin, N. S. A. W.

2017-01-01

Workers are exposed to a variety of heavy metal pollutants that are released into the environment as a consequence of workplace activities. This chemical pollutants are incorporated into the human by varies of routes entry and can then be stored and distributed in different tissues, consequently have a potential to lead an adverse health effects and/or diseases. As to minimize the impact, a control measures should be taken to avoid these effects and human biological marker is a very effective tool in the assessment of occupational exposure and potential related risk as the results is normally accurate and reproducible. Toenail is the ideal matrix for most common heavy metals due to its reliability and practicality compared to other biological samples as well as it is a non-invasive and this appears as a huge advantage of toenail as a biomarker. This paper reviews studies that measure the heavy metals concentration in toenail as non-invasive matrix which later may adapt in the investigation of metal fume emitted from welding process. The development of new methodology and modern analytical techniques has allowed the use of toenail as non-invasive approach. The presence of a heavy metal in this matrix reflects an exposure but the correlations between heavy metal levels in the toenail must be established to ensure that these levels are related to the total body burden. These findings suggest that further studies on interactions of these heavy metals in metal fumes utilizing toenail biomarker endpoints are highly warranted especially among welders.

Short term exposure to cooking fumes and pulmonary function

Directory of Open Access Journals (Sweden)

Qvenild Torgunn

2009-05-01

Full Text Available Abstract Background Exposure to cooking fumes may have different deleterious effects on the respiratory system. The aim of this study was to look at possible effects from inhalation of cooking fumes on pulmonary function. Methods Two groups of 12 healthy volunteers (A and B stayed in a model kitchen for two and four hours respectively, and were monitored with spirometry four times during twenty four hours, on one occasion without any exposure, and on another with exposure to controlled levels of cooking fumes. Results The change in spirometric values during the day with exposure to cooking fumes, were not statistically significantly different from the changes during the day without exposure, with the exception of forced expiratory time (FET. The change in FET from entering the kitchen until six hours later, was significantly prolonged between the exposed and the unexposed day with a 15.7% increase on the exposed day, compared to a 3.2% decrease during the unexposed day (p-value = 0.03. The same tendency could be seen for FET measurements done immediately after the exposure and on the next morning, but this was not statistically significant. Conclusion In our experimental setting, there seems to be minor short term spirometric effects, mainly affecting FET, from short term exposure to cooking fumes.

Type I interferon and pattern recognition receptor signaling following particulate matter inhalation

Directory of Open Access Journals (Sweden)

Erdely Aaron

2012-07-01

Full Text Available Abstract Background Welding, a process that generates an aerosol containing gases and metal-rich particulates, induces adverse physiological effects including inflammation, immunosuppression and cardiovascular dysfunction. This study utilized microarray technology and subsequent pathway analysis as an exploratory search for markers/mechanisms of in vivo systemic effects following inhalation. Mice were exposed by inhalation to gas metal arc – stainless steel (GMA-SS welding fume at 40 mg/m3 for 3 hr/d for 10 d and sacrificed 4 hr, 14 d and 28 d post-exposure. Whole blood cells, aorta and lung were harvested for global gene expression analysis with subsequent Ingenuity Pathway Analysis and confirmatory qRT-PCR. Serum was collected for protein profiling. Results The novel finding was a dominant type I interferon signaling network with the transcription factor Irf7 as a central component maintained through 28 d. Remarkably, these effects showed consistency across all tissues indicating a systemic type I interferon response that was complemented by changes in serum proteins (decreased MMP-9, CRP and increased VCAM1, oncostatin M, IP-10. In addition, pulmonary expression of interferon α and β and Irf7 specific pattern recognition receptors (PRR and signaling molecules (Ddx58, Ifih1, Dhx58, ISGF3 were induced, an effect that showed specificity when compared to other inflammatory exposures. Also, a canonical pathway indicated a coordinated response of multiple PRR and associated signaling molecules (Tlr7, Tlr2, Clec7a, Nlrp3, Myd88 to inhalation of GMA-SS. Conclusion This methodological approach has the potential to identify consistent, prominent and/or novel pathways and provides insight into mechanisms that contribute to pulmonary and systemic effects following toxicant exposure.

Biomonitoring for iron, manganese, chromium, aluminum, nickel and cadmium in workers exposed to welding fume: a preliminary study

Directory of Open Access Journals (Sweden)

Mulyana

2015-05-01

Full Text Available The control of exposure to welding fumes is increasing importance in promoting a healthy, safe and productive work environment. This study is a case-control design, random study was conducted among welder (56 subjects and non welder (39 subjects with more than 1 years experience in the same job task in an automotive parts manufactory within the industrial area at Cikarang in 2013. All subjects were completed physical examination, informed consent and questionnaire. Blood heavy metals were determined by Inductively-Coupled Plasma Mass Spectrometry (ICP-MS. Whole blood iron, manganese, chromium and lead in welder were higher than non-welder, but not different for aluminum, nickel and cadmium. In welder, chromium and manganese correlated with smoking status, cadmium correlated with age and smoking status. In multivariate analysis, wholeblood cadmium correlates with age and smoking status.

Comprehensive proteome analysis of nasal lavage samples after controlled exposure to welding nanoparticles shows an induced acute phase and a nuclear receptor, LXR/RXR, activation that influence the status of the extracellular matrix.

Science.gov (United States)

Ali, Neserin; Ljunggren, Stefan; Karlsson, Helen M; Wierzbicka, Aneta; Pagels, Joakim; Isaxon, Christina; Gudmundsson, Anders; Rissler, Jenny; Nielsen, Jörn; Lindh, Christian H; Kåredal, Monica

2018-01-01

Epidemiological studies have shown that many welders experience respiratory symptoms. During the welding process a large number of airborne nanosized particles are generated, which might be inhaled and deposited in the respiratory tract. Knowledge of the underlying mechanisms behind observed symptoms is still partly lacking, although inflammation is suggested to play a central role. The aim of this study was to investigate the effects of welding fume particle exposure on the proteome expression level in welders suffering from respiratory symptoms, and changes in protein mediators in nasal lavage samples were analyzed. Such mediators will be helpful to clarify the pathomechanisms behind welding fume particle-induced effects. In an exposure chamber, 11 welders with work-related symptoms in the lower airways during the last month were exposed to mild-steel welding fume particles (1 mg/m 3 ) and to filtered air, respectively, in a double-blind manner. Nasal lavage samples were collected before, immediately after, and the day after exposure. The proteins in the nasal lavage were analyzed with two different mass spectrometry approaches, label-free discovery shotgun LC-MS/MS and a targeted selected reaction monitoring LC-MS/MS analyzing 130 proteins and four in vivo peptide degradation products. The analysis revealed 30 significantly changed proteins that were associated with two main pathways; activation of acute phase response signaling and activation of LXR/RXR, which is a nuclear receptor family involved in lipid signaling. Connective tissue proteins and proteins controlling the degradation of such tissues, including two different matrix metalloprotease proteins, MMP8 and MMP9, were among the significantly changed enzymes and were identified as important key players in the pathways. Exposure to mild-steel welding fume particles causes measurable changes on the proteome level in nasal lavage matrix in exposed welders, although no clinical symptoms were manifested. The

Flow injection determination of lead and cadmium in hair samples from workers exposed to welding fumes

International Nuclear Information System (INIS)

Cespon-Romero, R.M.; Yebra-Biurrun, M.C.

2007-01-01

A flow injection procedure involving continuous acid leaching for lead and cadmium determination in hair samples of persons in permanent contact with a polluted workplace environment by flame atomic absorption spectrometry is proposed. Variables such as sonication time, nature and concentration of the acid solution used as leaching solution, leaching temperature, flow-rate of the continuous manifold, leaching solution volume and hair particle size were simultaneously studied by applying a Plackett-Burman design approach. Results showed that nitric acid concentration (leaching solution), leaching temperature and sonication time were statistically significant variables (confidence interval of 95%). These last two variables were finally optimised by using a central composite design. The proposed procedure allowed the determination of cadmium and lead with limits of detection 0.1 and 1.0 μg g -1 , respectively. The accuracy of the developed procedure was evaluated by the analysis of a certified reference material (CRM 397, human hair, from the BCR). The proposed method was applied with satisfactory results to the determination of Cd and Pb in human hair samples of workers exposed to welding fumes

Welding Emissions in Shipbuilding and Repair (Briefing Charts)

Science.gov (United States)

2009-09-03

gas – GTAW –uses shield gas, but low emissions –aka TIG – SAW – lowest rate, solid wire weld covered with flux material 7 Naval Facilities...Reduced fume generation rate •Measurement of Cr(VI) –SMAW over operating range of consumable –GTAW or other processes of interest to DoD • Welding ...Engineering Service Center Welding Emissions in Shipbuilding and Repair Kathleen M Paulson, PE Port Hueneme, CA 3 September 2009 Report

Exposure of healthy subjects with emissions from a gas metal arc welding process: part 3--biological effect markers and lung function.

Science.gov (United States)

Brand, P; Bischof, K; Siry, L; Bertram, J; Schettgen, T; Reisgen, U; Kraus, T; Gube, M

2013-01-01

Metal active gas welding (MAG) is a widely-used welding technique resulting in high emissions of welding fume particles. This study investigated whether short-term exposure to these fume particles results in changes in lung function and early stages of inflammatory reactions. Twelve healthy, young male subjects were exposed to MAG fumes for 6 h with three different exposure concentrations in a three-fold cross-over study design. Exposure was performed in the "Aachen Workplace Simulation Laboratory" under controlled conditions with constant fume concentration. Fume concentrations were 0, 1, and 2.5 mg m(-3) in randomized order. Before and after each exposure, spirometry, and impulse oscillometry were performed and breath condensate samples were collected in order to quantify inflammatory markers like Nitrate, Nitrite, Nitrotyrosine, Hydroxyprolin and Malondialdehyde. A significant dependency on the exposure concentration could not be established for any of the endpoint parameters. In healthy, young subjects neither changes in spirometry nor changes in inflammatory markers measured in exhaled breath condensate could be detected after short-term exposure.

30 CFR 71.700 - Inhalation hazards; threshold limit values for gases, dust, fumes, mists, and vapors.

Science.gov (United States)

2010-07-01

... gases, dust, fumes, mists, and vapors. 71.700 Section 71.700 Mineral Resources MINE SAFETY AND HEALTH... limit values for gases, dust, fumes, mists, and vapors. (a) No operator of an underground coal mine and... limit values adopted by the American Conference of Governmental Industrial Hygienists in “Threshold...

Exposure of welders to fumes, Cr, Ni, Cu and gases in Dutch industries

NARCIS (Netherlands)

Wal, J.F. van der

1985-01-01

The exposure of welders in Dutch industries to total particulate, chromium, nickel and copper fume during the welding of unalloyed, stainless and high alloyed steels has been investigated. The exposure to the gases NO2, NO and ozone is also discussed. The results are presented in tables and graphs.

SIMRAC welding occupational health and safety resources CD and booklet on welding fume

CSIR Research Space (South Africa)

Stanton, WD

2003-07-01

Full Text Available thanks go to TWI for permission to add their FAQs and Job Knowledge information on welding health and safety. I should also like to express my gratitude to the American Welding Society (AWS) for permission to utilise their Safety and Health Fact... published without the support and encouragement of Professor Mary Ross, SIMPROSS. Finally, my gratitude goes to Vali Yousefi, National Centre for Occupational Health (NCOH), Jim Guild and Ted Barwise SAIW, for their valuable comments and contributions...

Human biomonitoring of aluminium after a single, controlled manual metal arc inert gas welding process of an aluminium-containing worksheet in nonwelders.

Science.gov (United States)

Bertram, Jens; Brand, Peter; Hartmann, Laura; Schettgen, Thomas; Kossack, Veronika; Lenz, Klaus; Purrio, Ellwyn; Reisgen, Uwe; Kraus, Thomas

2015-10-01

Several existing field studies evaluate aluminium welding works but no thoroughly controlled exposure scenario for welding fume has been described yet. This study provides information about the uptake and elimination of aluminium from welding fumes under controlled conditions. In the Aachen Workplace Simulation Laboratory, we are able to generate welding fumes of a defined particle mass concentration. We exposed 12, until then occupationally unexposed participants with aluminium-containing welding fumes of a metal inert gas (MIG) welding process of a total dust mass concentration of 2.5 mg/m(3) for 6 h. Room air filter samples were collected, and the aluminium concentration in air derived. Urine and plasma samples were collected directly before and after the 6-h lasting exposure, as well as after 1 and 7 days. Human biomonitoring methods were used to determine the aluminium content of the samples with high-resolution continuum source atomic absorption spectrometry. Urinary aluminium concentrations showed significant changes after exposure compared to preexposure levels (mean t(1) (0 h) 13.5 µg/L; mean t(2) (6 h) 23.5 µg/L). Plasma results showed the same pattern but pre-post comparison did not reach significance. We were able to detect a significant increase of the internal aluminium burden of a single MIG aluminium welding process in urine, while plasma failed significance. Biphasic elimination kinetic can be observed. The German BAT of 60 µg/g creatinine was not exceeded, and urinary aluminium returned nearly to baseline concentrations after 7 days.

Occupational asthma due to manual metal-arc welding of special stainless steels.

Science.gov (United States)

Hannu, T; Piipari, R; Kasurinen, H; Keskinen, H; Tuppurainen, M; Tuomi, T

2005-10-01

Occupational asthma (OA) can be induced by fumes of manual metal-arc welding on stainless steel. In recent years, the use of special stainless steels (SSS) with high chromium content has increased. This study presents two cases of OA caused by manual metal-arc welding on SSS. In both cases, the diagnosis of OA was based on respiratory symptoms, occupational exposure and positive findings in the specific challenge tests. In the first case, a 46-yr-old welder had experienced severe dyspnoea while welding SSS (SMO steel), but not in other situations. Challenge tests with both mild steel and stainless steel using a common electrode were negative. Welding SSS with a special electrode caused a delayed 37% drop in forced expiratory volume in one second (FEV1). In the second case, a 34-yr-old male had started to experience dyspnoea during the past few years, while welding especially SSS (Duplex steel). The workplace peak expiratory flow monitoring was suggestive of OA. Challenge tests with both mild steel and stainless steel using a common electrode did not cause bronchial obstruction. Welding SSS with a special electrode caused a delayed 31% drop in FEV1. In conclusion, exposure to manual metal-arc welding fumes of special stainless steel should be considered as a new cause of occupational asthma.

Effect of gasoline fumes on reproductive function in male albino rats.

Science.gov (United States)

Owagboriaye, Folarin O; Dedeke, Gabriel A; Ashidi, Joseph S; Aladesida, Adeyinka A; Olooto, Wasiu E

2018-02-01

The increase in the frequency of exposure to gasoline fumes and the growing incidence of infertility among humans has been a major concern and subject of discussion over the years in Nigeria. We therefore present the reproductive effect of gasoline fumes on inhalation exposure in 40 male albino rats. The rats were randomized into five experimental treatments (T) with eight rats per treatment. T1 (control) was exposed to distilled water while T2, T3, T4, and T5 were exposed to gasoline fumes in exposure chambers for 1, 3, 5, and 9 h daily respectively for 12 weeks. Serum level of testosterone, follicle stimulating hormone (FSH), luteinizing hormone (LH), prolactin, oxidative stress markers in the testicular tissue, epididymal sperm health assessment, and testicular histopathology of the rats were used as a diagnostic marker of reproductive dysfunction. Significant (p percentage motility in the exposed rats were observed. Significant (p < 0.05) increased in abnormal sperm cells characterized by damaged head, bent tail, damaged tail, and without head were also observed in the exposed rats. Histopathologically, severe degenerative testicular architectural lesions characterized by alterations in all the generations of sperm cells and reduction of interstitial cells were seen in the exposed rats. Gasoline fume is thus said to interfere with spermatogenesis and impair fertility in male gonad.

Particle release and control of worker exposure during laboratory-scale synthesis, handling and simulated spills of manufactured nanomaterials in fume hoods

Science.gov (United States)

Fonseca, Ana S.; Kuijpers, Eelco; Kling, Kirsten I.; Levin, Marcus; Koivisto, Antti J.; Nielsen, Signe H.; Fransman, W.; Fedutik, Yijri; Jensen, Keld A.; Koponen, Ismo K.

2018-02-01

Fume hoods are one of the most common types of equipment applied to reduce the potential of particle exposure in laboratory environments. A number of previous studies have shown particle release during work with nanomaterials under fume hoods. Here, we assessed laboratory workers' inhalation exposure during synthesis and handling of CuO, TiO2 and ZnO in a fume hood. In addition, we tested the capacity of a fume hood to prevent particle release to laboratory air during simulated spillage of different powders (silica fume, zirconia TZ-3Y and TiO2). Airborne particle concentrations were measured in near field, far field, and in the breathing zone of the worker. Handling CuO nanoparticles increased the concentration of small particles (control during synthesis and handling of nanomaterials. An appropriate fume hood with adequate sash height and face velocity prevents 98.3% of particles release into the surrounding environment. Care should still be made to consider spills and high cleanliness to prevent exposure via resuspension and inadvertent exposure by secondary routes.

Evaluation of the molecular mechanisms associated with cytotoxicity and inflammation after pulmonary exposure to different metal-rich welding particles.

Science.gov (United States)

Shoeb, Mohammad; Kodali, Vamsi; Farris, Breanne; Bishop, Lindsey M; Meighan, Terence; Salmen, Rebecca; Eye, Tracy; Roberts, Jenny R; Zeidler-Erdely, Patti; Erdely, Aaron; Antonini, James M

2017-08-01

Welding generates a complex aerosol of incidental nanoparticles and cytotoxic metals, such as chromium (Cr), manganese (Mn), nickel (Ni), and iron (Fe). The goal was to use both in vivo and in vitro methodologies to determine the mechanisms by which different welding fumes may damage the lungs. Sprague-Dawley rats were treated by intratracheal instillation (ITI) with 2.0 mg of gas metal arc-mild steel (GMA-MS) or manual metal arc-stainless steel (MMA-SS) fumes or saline (vehicle control). At 1, 3, and 10 days, bronchoalveolar lavage (BAL) was performed to measure lung toxicity. To assess molecular mechanisms of cytotoxicity, RAW264.7 cells were exposed to both welding fumes for 24 h (0-100 μg/ml). Fume composition was different: MMA-SS (41% Fe, 29% Cr, 17% Mn, 3% Ni) versus GMA-MS (85% Fe, 14% Mn). BAL indicators of lung injury and inflammation were increased by MMA-SS at all time points and by GMA-MS at 3 and 10 days after exposure. RAW264.7 cells exposed to MMA-SS had elevated generation of reactive oxygen species (ROS), protein-HNE (P-HNE) adduct formation, activation of ERK1/2, and expression of cyclooxygenase-2 (COX-2) compared to GMA-MS and control. Increased generation of ROS due to MMA-SS exposure was confirmed by increased expression of Nrf2 and heme oxygenase-1 (HO-1). Results of in vitro studies provide evidence that stainless steel welding fume mediate inflammatory responses via activation of ROS/P-HNE/ERK1/2/Nrf2 signaling pathways. These findings were corroborated by elevated expression of COX-2, Nrf2, and HO-1 in homogenized lung tissue collected 1 day after in vivo exposure.

Characteristics of welding fume aerosol investigated in three Swedish workshops

International Nuclear Information System (INIS)

Isaxon, C; Pagels, J; Gudmundsson, A; Bohgard, M; Asbach, C; John, A C; Kuhlbusch, T A J; Karlsson, J E; Kammer, R; Tinnerberg, H; Nielsen, J

2009-01-01

Potentially high human exposures to nanometer sized airborne particles occur due to welding and other thermal processes in industrial environments. Detailed field measurements of physical and chemical particle characteristics were performed in three work-shops in Sweden. Measurements were performed both in the plume 5-20 cm above the welding point and in the background air (more than 5 m away from the nearest known particle source). Particle number and mass concentrations were measured on-line. A low pressure impactor was used for size-resolved chemical particle composition. The in-plume measurements generated the chemical signatures for different welding processes. These signatures were then used to identify contributions from various processes to the particle concentrations in different size classes. The background number and mass concentrations increased by more than an order of magnitude during intense activities in the work-shops compared to low activities during breaks.

Characteristics of welding fume aerosol investigated in three Swedish workshops

Energy Technology Data Exchange (ETDEWEB)

Isaxon, C; Pagels, J; Gudmundsson, A; Bohgard, M [Division of Ergonomics and Aerosol Technology (EAT), Lund University, Faculty of Engineering, PO Box 118, SE-221 00, Lund (Sweden); Asbach, C; John, A C; Kuhlbusch, T A J [Institute of Energy and Environmental Technology, (IUTA), Duisburg (Germany); Karlsson, J E; Kammer, R; Tinnerberg, H; Nielsen, J [Occupational and Environmental Health, Lund University, University Hospital, Lund (Sweden)

2009-02-01

Potentially high human exposures to nanometer sized airborne particles occur due to welding and other thermal processes in industrial environments. Detailed field measurements of physical and chemical particle characteristics were performed in three work-shops in Sweden. Measurements were performed both in the plume 5-20 cm above the welding point and in the background air (more than 5 m away from the nearest known particle source). Particle number and mass concentrations were measured on-line. A low pressure impactor was used for size-resolved chemical particle composition. The in-plume measurements generated the chemical signatures for different welding processes. These signatures were then used to identify contributions from various processes to the particle concentrations in different size classes. The background number and mass concentrations increased by more than an order of magnitude during intense activities in the work-shops compared to low activities during breaks.

Fumed silica. Fumed silica

Energy Technology Data Exchange (ETDEWEB)

Sukawa, T.; Shirono, H. (Nippon Aerosil Co. Ltd., Tokyo (Japan))

1991-10-18

The fumed silica is explained in particulate superfineness, high purity, high dispersiveness and other remarkable characteristics, and wide application. The fumed silica, being presently produced, is 7 to 40nm in average primary particulate diameter and 50 to 380m{sup 2}/g in specific surface area. On the surface, there coexist hydrophilic silanol group (Si-OH) and hydrophobic siloxane group (Si-O-Si). There are many characteristics, mutually different between the fumed silica, made hydrophobic by the surface treatment, and untreated hydrophilic silica. The treated silica, if added to the liquid product, serves as agent to heighten the viscosity, prevent the sedimentation and disperse the particles. The highest effect is given to heighten the viscosity in a region of 4 to 9 in pH in water and alcohol. As filling agent to strengthen the elastomer and polymer, and powder product, it gives an effect to prevent the consolidation and improve the fluidity. As for its other applications, utilization is made of particulate superfineness, high purity, thermal insulation properties and adsorption characteristics. 2 to 3 patents are published for it as raw material of quartz glass. 38 refs., 16 figs., 4 tabs.

Visibility in sodium fume

International Nuclear Information System (INIS)

Hughes, G.W.; Anderson, N.R.

1971-01-01

The appearance of sodium fume of unknown concentration and the effects of short term exposure on unprotected workers is described. The molecular extinction coefficient of sodium fume is calculated from which light transmission data, and a rapid method for the estimation of the fume concentration is proposed. (author)

Influence of shielding gas on fume formation rate and particle size distribution for optimised GMAW

International Nuclear Information System (INIS)

Carpenter, K.R.; Monaghan, B.J.; Nicholson, A.; Cuiuri, D.; Norrish, J.

2010-01-01

The influence of shielding gas on fume formation rate (FFR) and particle size distribution has been investigated by using a technique developed for automatic control of the welding voltage in gas metal arc welding (GMAW). The results for automatic control are compared with the use of a fixed voltage. Significant reductions in FFR and a general decrease in average particle size were observed using the automatic control technique. This reduction in FFR was attributed to improved metal transfer stability, via a reduction in the occurrence of repelled globular transfer, by promoting the 'drop-spray' transfer condition, together with a reduction in the arc length. FFR and particle size were strongly related to the C O2 content of the shielding gas, where FFR increased as percent C 02 increased, due mainly to the dominant influence of C O2 on weld transfer and arc characteristics. The results indicate that FFR for GMAW in the spray regime should be determined by using optimised welding conditions for each shielding gas composition.

Combustion-derived nanoparticles: A review of their toxicology following inhalation exposure

Directory of Open Access Journals (Sweden)

Mills Nicholas

2005-10-01

Full Text Available Abstract This review considers the molecular toxicology of combustion-derived nanoparticles (CDNP following inhalation exposure. CDNP originate from a number of sources and in this review we consider diesel soot, welding fume, carbon black and coal fly ash. A substantial literature demonstrates that these pose a hazard to the lungs through their potential to cause oxidative stress, inflammation and cancer; they also have the potential to redistribute to other organs following pulmonary deposition. These different CDNP show considerable heterogeneity in composition and solubility, meaning that oxidative stress may originate from different components depending on the particle under consideration. Key CDNP-associated properties of large surface area and the presence of metals and organics all have the potential to produce oxidative stress. CDNP may also exert genotoxic effects, depending on their composition. CDNP and their components also have the potential to translocate to the brain and also the blood, and thereby reach other targets such as the cardiovascular system, spleen and liver. CDNP therefore can be seen as a group of particulate toxins unified by a common mechanism of injury and properties of translocation which have the potential to mediate a range of adverse effects in the lungs and other organs and warrant further research.

222-S LABORATORY FUME HOOD TESTING STUDY

International Nuclear Information System (INIS)

RUELAS, B.H.

2007-01-01

The 222-S Laboratory contains 155 active fume hoods that are used to support analytical work with radioactive and/or toxic materials. The performance of a fume hood was brought into question after employees detected odors in the work area while mixing chemicals within the subject fume hood. Following the event, testing of the fume hood was conducted to assess the performance of the fume hood. Based on observations from the testing, it was deemed appropriate to conduct performance evaluations of other fume hoods within the laboratory

Production and testing of flexible welding flux rods, used for protecting briquetting press molds from wear

Energy Technology Data Exchange (ETDEWEB)

Loescher, B.; Czerwinski, M.; Dittrich, V.

1985-11-01

Production, properties and trial application are discussed for the Feroplast ZIS 218 welding powder rod, developed for automated surface armouring of brown coal briquetting press moulds by arc welding. The welding rod has a diameter of 8 mm and can be bent to a radius of less than 150 mm for reeling. The welding rod is produced by mixing 9% plasticizer (Miravithen and polyisobutylene according to GDR patent 203 269) to the steel welding powder. Weldability of the rod proved to be favourable; there was no emission of toxic fumes during welding. Microscopic studies of the welded surface coating showed that welding with 650A achieved the best coat pore structure. At the Schwarze Pumpe Gasworks the trial service life of various briquet press moulds, reinforced with Ferroplast ZIS 218, proved to be not shorter than that of moulds reinforced with the conventional ZIS powder welding method. 1 reference.

Sustainability assessment of shielded metal arc welding (SMAW) process

Science.gov (United States)

Alkahla, Ibrahim; Pervaiz, Salman

2017-09-01

Shielded metal arc welding (SMAW) process is one of the most commonly employed material joining processes utilized in the various industrial sectors such as marine, ship-building, automotive, aerospace, construction and petrochemicals etc. The increasing pressure on manufacturing sector wants the welding process to be sustainable in nature. The SMAW process incorporates several types of inputs and output streams. The sustainability concerns associated with SMAW process are linked with the various input and output streams such as electrical energy requirement, input material consumptions, slag formation, fumes emission and hazardous working conditions associated with the human health and occupational safety. To enhance the environmental performance of the SMAW welding process, there is a need to characterize the sustainability for the SMAW process under the broad framework of sustainability. Most of the available literature focuses on the technical and economic aspects of the welding process, however the environmental and social aspects are rarely addressed. The study reviews SMAW process with respect to the triple bottom line (economic, environmental and social) sustainability approach. Finally, the study concluded recommendations towards achieving economical and sustainable SMAW welding process.

Characterization of the early pulmonary inflammatory response associated with PTFE fume exposure

Science.gov (United States)

Johnston, C. J.; Finkelstein, J. N.; Gelein, R.; Baggs, R.; Oberdorster, G.; Clarkson, T. W. (Principal Investigator)

1996-01-01

Heating of polytetrafluoroethylene (PTFE) has been described to release fumes containing ultrafine particles (approximately 18 nm diam). These fumes can be highly toxic in the respiratory tract inducing extensive pulmonary edema with hemorrhagic inflammation. Fischer-344 rats were exposed to PTFE fumes generated by temperatures ranging from 450 to 460 degrees C for 15 min at an exposure concentration of 5 x 10(5) particles/cm3, equivalent to approximately 50 micrograms/m3. Responses were examined 4 hr post-treatment when these rats demonstrated 60-85% neutrophils (PMNs) in their lung lavage. Increases in abundance for messages encoding the antioxidants manganese superoxide dismutase and metallothionein (MT) increased 15- and 40-fold, respectively. For messages encoding the pro- and anti-inflammatory cytokines: inducible nitric oxide synthase, interleukin 1 alpha, 1 beta, and 6 (IL-1 alpha, IL-1 beta, and IL-6), macrophage inflammatory protein-2, and tumor necrosis factor-alpha (TNF alpha) increases of 5-, 5-, 10-, 40-, 40-, and 15-fold were present. Vascular endothelial growth factor, which may play a role in the integrity of the endothelial barrier, was decreased to 20% of controls. In situ sections were hybridized with 33P cRNA probes encoding IL-6, MT, surfactant protein C, and TNF alpha. Increased mRNA abundance for MT and IL-6 was expressed around all airways and interstitial regions with MT and IL-6 demonstrating similar spatial distribution. Large numbers of activated PMNs expressed IL-6, MT, and TNF alpha. Additionally, pulmonary macrophages and epithelial cells were actively involved. These observations support the notion that PTFE fumes containing ultrafine particles initiate a severe inflammatory response at low inhaled particle mass concentrations, which is suggestive of an oxidative injury. Furthermore, PMNs may actively regulate the inflammatory process through cytokine and antioxidant expression.

Reducing the cytotoxicity of inhalable engineered nanoparticles via in situ passivation with biocompatible materials

International Nuclear Information System (INIS)

Byeon, Jeong Hoon; Park, Jae Hong; Peters, Thomas M.; Roberts, Jeffrey T.

2015-01-01

Highlights: • The cytotoxicity of model welding particles was modulated through in situ passivation. • Model welding particles were incorporated with chitosan nanoparticles for passivation. • In vitro assay revealed that the passivated particles had a lower cytotoxicity. • Passivation with chitosan adhesive or graphite paste could also reduce cytotoxicity. • This method would be suitable for efficient reduction of inhalable toxic components. - Abstract: The cytotoxicity of model welding nanoparticles was modulated through in situ passivation with soluble biocompatible materials. A passivation process consisting of a spark discharge particle generator coupled to a collison atomizer as a co-flow or counter-flow configuration was used to incorporate the model nanoparticles with chitosan. The tested model welding nanoparticles are inhaled and that A549 cells are a human lung epithelial cell line. Measurements of in vitro cytotoxicity in A549 cells revealed that the passivated nanoparticles had a lower cytotoxicity (>65% in average cell viability, counter-flow) than the untreated model nanoparticles. Moreover, the co-flow incorporation between the nanoparticles and chitosan induced passivation of the nanoparticles, and the average cell viability increased by >80% compared to the model welding nanoparticles. As a more convenient way (additional chitosan generation and incorporation devices may not be required), other passivation strategies through a modification of the welding rod with chitosan adhesive and graphite paste did also enhance average cell viability (>58%). The approach outlined in this work is potentially generalizable as a new platform, using only biocompatible materials in situ, to treat nanoparticles before they are inhaled

Reducing the cytotoxicity of inhalable engineered nanoparticles via in situ passivation with biocompatible materials

Energy Technology Data Exchange (ETDEWEB)

Byeon, Jeong Hoon, E-mail: postjb@yu.ac.kr [School of Mechanical Engineering, Yeungnam University, Gyeongsan 712-749 (Korea, Republic of); Park, Jae Hong; Peters, Thomas M. [Department of Occupational and Environmental Health, University of Iowa, IA 52242 (United States); Roberts, Jeffrey T., E-mail: jtrob@purdue.edu [Department of Chemistry, Purdue University, IN 47907 (United States)

2015-07-15

Highlights: • The cytotoxicity of model welding particles was modulated through in situ passivation. • Model welding particles were incorporated with chitosan nanoparticles for passivation. • In vitro assay revealed that the passivated particles had a lower cytotoxicity. • Passivation with chitosan adhesive or graphite paste could also reduce cytotoxicity. • This method would be suitable for efficient reduction of inhalable toxic components. - Abstract: The cytotoxicity of model welding nanoparticles was modulated through in situ passivation with soluble biocompatible materials. A passivation process consisting of a spark discharge particle generator coupled to a collison atomizer as a co-flow or counter-flow configuration was used to incorporate the model nanoparticles with chitosan. The tested model welding nanoparticles are inhaled and that A549 cells are a human lung epithelial cell line. Measurements of in vitro cytotoxicity in A549 cells revealed that the passivated nanoparticles had a lower cytotoxicity (>65% in average cell viability, counter-flow) than the untreated model nanoparticles. Moreover, the co-flow incorporation between the nanoparticles and chitosan induced passivation of the nanoparticles, and the average cell viability increased by >80% compared to the model welding nanoparticles. As a more convenient way (additional chitosan generation and incorporation devices may not be required), other passivation strategies through a modification of the welding rod with chitosan adhesive and graphite paste did also enhance average cell viability (>58%). The approach outlined in this work is potentially generalizable as a new platform, using only biocompatible materials in situ, to treat nanoparticles before they are inhaled.

Influence of Metal Transfer Stability and Shielding Gas Composition on CO and CO2 Emissions during Short-circuiting MIG/MAG Welding

Directory of Open Access Journals (Sweden)

Valter Alves de Meneses

Full Text Available Abstract: Several studies have demonstrated the influence of parameters and shielding gas on metal transfer stability or on the generation of fumes in MIG/MAG welding, but little or nothing has been discussed regarding the emission of toxic and asphyxiating gases, particularly as it pertains to parameterization of the process. The purpose of this study was to analyze and evaluate the effect of manufacturing aspects of welding processes (short-circuit metal transfer stability and shielding gas composition on the gas emission levels during MIG/MAG welding (occupational health and environmental aspects. Using mixtures of Argon with CO2 and O2 and maintaining the same average current and the same weld bead volume, short-circuit welding was performed with carbon steel welding wire in open (welder’s breathing zone and confined environments. The welding voltage was adjusted to gradually vary the transfer stability. It was found that the richer the composition of the shielding gas is in CO2, the more CO and CO2 are generated by the arc. However, unlike fume emission, voltage and transfer stability had no effect on the generation of these gases. It was also found that despite the large quantity of CO and CO2 emitted by the arc, especially when using pure CO2 shielding gas, there was no high level residual concentration of CO and CO2 in or near the worker’s breathing zone, even in confined work cells.

The Pozzolanic reaction of silica fume

DEFF Research Database (Denmark)

Jensen, Ole Mejlhede

2012-01-01

Silica fume is a very important supplementary cementitious binder in High-Performance and Ultra High-Performance Concretes. Through its pozzolanic reaction the silica fume densifies the concrete micro-structure, in particular it strengthens the paste-aggregate interfacial transition zone. In the ......Silica fume is a very important supplementary cementitious binder in High-Performance and Ultra High-Performance Concretes. Through its pozzolanic reaction the silica fume densifies the concrete micro-structure, in particular it strengthens the paste-aggregate interfacial transition zone....... In the present paper different aspects of the pozzolanic reaction of silica fume are investigated. These include chemical shrinkage, isothermal heat development and strength development. Key data for these are given and compared with theoretical calculations, and based on presented measurements the energy...

Combined effects of inhalation of Radon daughter products and tobacco smoke

International Nuclear Information System (INIS)

Chameaud, J.; Perraud, R.; Chretien, J.; Masse, R.; Lafuma, J.

1980-01-01

Over the last 10 years, more than 500 lung cancers have been induced in rats by inhalations of radon daughter products at various concentrations and cumulated doses. These cancers were compared with human cancers. Another study examines the cocarcinogenic effect of tobacco smoke. In the first experiment, 100 rats were exposed to a 4000-WLM (working level month) cumulated dose of radon daughter products. Fifty animals were then administered tobacco smoke by inhalation in a fume box during 5 months (i.e., for a total of 352 hr). In the group inhaling radon only, 17 cancers appeared; in the radon-tobacco group, 32 cancers were observed, many of them larger and more invasive than those seen in animals exposed to radon only. Under the same conditions tobacco smoke was inhaled by rats previously exposed to lower doses of radon daughter products (two groups of 30 rats each, at 500 and 100 WLM, respectively). Again, the number of cancers observed was greater than the number of cancers expected if the rats had inhaled radon only. The carcinogenic and potentiating action of tobacco smoke was clearly demonstrated

An Evaluation of a Welding Fumes Exhaust System. Agricultural Experiment Station Research Report 284.

Science.gov (United States)

Jacobs, C. O.

A study evaluated the feasibility of introducing unheated outside air into the airstream of a cross-flow welding exhaust system to reduce heating energy costs of a school welding laboratory. The physical facility used was the agricultural mechanics laboratory at the University of Arizona, which is similar to facilities in which instruction in…

Retractable Pin Tools for the Friction Stir Welding Process

Science.gov (United States)

1998-01-01

Two companies have successfully commercialized a specialized welding tool developed at the Marshall Space Flight Center (MSFC). Friction stir welding uses the high rotational speed of a tool and the resulting frictional heat created from contact to crush, 'stir' together, and forge a bond between two metal alloys. It has had a major drawback, reliance on a single-piece pin tool. The pin is slowly plunged into the joint between two materials to be welded and rotated as high speed. At the end of the weld, the single-piece pin tool is retracted and leaves a 'keyhole,' something which is unacceptable when welding cylindrical objects such as drums, pipes and storage tanks. Another drawback is the requirement for different-length pin tools when welding materials of varying thickness. An engineer at the MSFC helped design an automatic retractable pin tool that uses a computer-controlled motor to automatically retract the pin into the shoulder of the tool at the end of the weld, preventing keyholes. This design allows the pin angle and length to be adjusted for changes in material thickness and results in a smooth hole closure at the end of the weld. Benefits of friction stir welding, using the MSFC retractable pin tool technology, include the following: The ability to weld a wide range of alloys, including previously unweldable and composite materials; provision of twice the fatigue resistance of fusion welds and no keyholes; minimization of material distortion; no creation of hazards such as welding fumes, radiation, high voltage, liquid metals, or arcing; automatic retraction of the pin at the end of the weld; and maintaining full penetration of the pin.

The measurement of released radionuclides during TIG-Welding and Grinding

International Nuclear Information System (INIS)

Reichelt, A.; Lehmann, K.-H.; Reineking, A.; Eder, E.

2000-01-01

The radiological relevance of the TIG welding using thoriated tungsten electrodes has recently been proved by means of different studies. As a result of this the TUEV Sueddeutschland and the University of Goettingen have carried out special investigations concerning the release of radionuclides during TIG welding. The main emphasis of these investigations were the representativity of various sampling techniques, the influence of various parameters during welding as well as the determination of activity size distributions related to the aerodynamic diameter of the inhaled aerosols. The properties of the tungsten rods are improved through the addition of radioactive thorium. We investigated the radiation exposure by handling with thoriated tungsten welding rods. We investigated the different exposure pathways and determined the specific activity in dependence to the different types of welding rods. By carrying out surveys with the users, we determined the exposure pathways for the individual exposed persons: TIG - hand-welders', TIG 'machine-welders', labourers, other persons. We measured the activity concentration of the breathing air while welding, at grinding the electrodes and by staying in the rooms where usually it's welded. The size distribution of the aerosol-attached activity was determined with several kinds of impactors. The main emphasis was the comparison of the different sampling systems at the measuring of the activity concentration of the breathing air. Selective sampling by impactors: · Berner-impactor, stationary · Sierra-impactor, stationary · Anderson-Imcaktor, stationary · Marple-impactor, personal sampler Aerosol sampling by air samplers · 5 personal air sampler · 2 stationary sampler, ring face · 2 stationary sampler, open face Rn-220-Measurements · Thoron-monitor Determination of activities on measuring filters · alpha spectrometry · low-level-gamma-spectrometry. For the various exposed persons, at the extern irradiation with gamma

Metal Cutting Theory and Friction Stir Welding Tool Design

Science.gov (United States)

Payton, Lewis N.

2003-01-01

Friction Stir Welding (FSW) is a relatively new industrial process that was invented at The Weld Institute (TWI, United Kingdom) and patented in 1992 under research funded by in part by the National Aeronautics and Space Administration (NASA). Often quoted advantages of the process include good strength and ductility along with minimization of residual stress and distortion. Less well advertised are the beneficial effects of this solid state welding process in the field of occupational and environmental safety. It produces superior weld products in difficult to weld materials without producing any toxic fumes or solid waste that must be controlled as hazardous waste. In fact, it reduces noise pollution in the workspace as well. In the early days of FSW, most welding was performed on modified machine tools, in particular on milling machines with modified milling cutters. In spite of the obvious milling heritage of the process, the techniques and lessons learned from almost 250 years of successful metalworking with milling machines have not been applied in the field of modern Friction Stir Welding. The goal of the current research was to study currently successful FSW tools and parameterize the process in such a way that the design of new tools for new materials could be accelerated. Along the way, several successful new tooling designs were developed for current issues at the Marshall Space Flight Center with accompanying patent disclosures

Increased risk of parkinsonism associated with welding exposure.

Science.gov (United States)

Racette, Brad A; Criswell, Susan R; Lundin, Jessica I; Hobson, Angela; Seixas, Noah; Kotzbauer, Paul T; Evanoff, Bradley A; Perlmutter, Joel S; Zhang, Jing; Sheppard, Lianne; Checkoway, Harvey

2012-10-01

Manganese (Mn), an established neurotoxicant, is a common component of welding fume. The neurological phenotype associated with welding exposures has not been well described. Prior epidemiologic evidence linking occupational welding to parkinsonism is mixed, and remains controversial. This was a cross-sectional and nested case-control study to investigate the prevalence and phenotype of parkinsonism among 811 shipyard and fabrication welders recruited from trade unions. Two reference groups included 59 non-welder trade workers and 118 newly diagnosed, untreated idiopathic PD patients. Study subjects were examined by a movement disorders specialist using the Unified Parkinson Disease Rating Scale motor subsection 3 (UPDRS3). Parkinsonism cases were defined as welders with UPDRS3 score ≥15. Normal was defined as UPDRS3welding. Adjusted prevalence ratios for parkinsonism were calculated in relation to quartiles of welding years. The overall prevalence estimate of parkinsonism was 15.6% in welding exposed workers compared to 0% in the reference group. Among welders, we observed a U-shaped dose-response relation between weighted welding exposure-years and parkinsonism. UPDRS3 scores for most domains were similar between welders and newly diagnosed idiopathic Parkinson disease (PD) patients, except for greater frequency of rest tremor and asymmetry in PD patients. This work-site based study among welders demonstrates a high prevalence of parkinsonism compared to nonwelding-exposed workers and a clinical phenotype that overlaps substantially with PD. Copyright © 2012 Elsevier Inc. All rights reserved.

Combined Performance of Polypropylene Fibre and Weld Slag in High Performance Concrete

Science.gov (United States)

Ananthi, A.; Karthikeyan, J.

2017-12-01

The effect of polypropylene fibre and weld slag on the mechanical properties of High Performance Concrete (HPC) containing silica fume as the mineral admixtures was experimentally verified in this study. Sixteen series of HPC mixtures(70 MPa) were designed with varying fibre fractions and Weld Slag (WS). Fibre added at different proportion (0, 0.1, 0.3 and 0.6%) to the weight of cement. Weld slag was substituted to the fine aggregate (0, 10, 20 and 30%) at volume. The addition of fibre decreases the slump at 5, 9 and 14%, whereas the substitution of weld slag decreases by about 3, 11 and 21% with respect to the control mixture. Mechanical properties like compressive strength, split tensile strength, flexural strength, Ultrasonic Pulse Velocity test (UPV) and bond strength were tested. Durability studies such as Water absorption and Sorptivity test were conducted to check the absorption of water in HPC. Weld slag of 10% and fibre dosage of 0.3% in HPC, attains the maximum strength and hence this combination is most favourable for the structural applications.

Chronic exposure to iron oxide, chromium oxide, and nickel oxide fumes of metal dressers in a steelworks

Science.gov (United States)

Jones, J. Graham; Warner, C. G.

1972-01-01

Graham Jones, J., and Warner, C. G. (1972).Brit. J. industr. Med.,29, 169-177. Chronic exposure to iron oxide, chromium oxide, and nickel oxide fumes of metal dressers in a steelworks. Occupational and medical histories, smoking habits, respiratory symptoms, chest radiographs, and ventilatory capacities were studied in 14 steelworkers employed as deseamers of steel ingots for periods of up to 16 years. The men were exposed for approximately five hours of each working shift to fume concentrations ranging from 1·3 to 294·1 mg/m3 made up mainly of iron oxide with varying proportions of chromium oxide and nickel oxide. Four of the men, with 14 to 16 years' exposure, showed radiological evidence of pneumoconiosis classified as ILO categories 2 or 3. Of these, two had pulmonary function within the normal range and two had measurable loss of function, moderate in one case and mild in the other. Many observers would diagnose these cases as siderosis but the authors consider that this term should be reserved for cases exposed to pure iron compounds. The correct diagnosis is mixed-dust pneumoconiosis and the loss of pulmonary function is caused by the effects of the mixture of metallic oxides. It is probable that inhalation of pure iron oxide does not cause fibrotic pulmonary changes, whereas the inhalation of iron oxide plus certain other substances obviously does. Images PMID:5021996

Dispersibility of silica fume in mortar and its effect on properties of mortar. Silica fume no bunsan to mortar no shotokusei

Energy Technology Data Exchange (ETDEWEB)

Oga, H; Uomoto, T [The University of Tokyo, Tokyo (Japan). Institute of Industrial Science

1992-08-01

Effect of silica fume dispersibility on concrete characteristics was discussed. Properties of mortar mixed with silica fume to exhibit compression strength varied with displacement rates, patterns, and mixing time of silica fume. In submerged curing age of 28 days, the compression strength in a mortar mixed with silica fume at 10% was affected only very little by the mixing time for both pelletizing and non-pelletizing types for up to 180 seconds. The strength increased thereafter with the mixing time. The compression strength at 1020 seconds showed higher value by about 150 kgf/cm [sup 2] than when no silica fume is added, with a difference because of patterns disappearing. In the case of a mixing time of 1020 seconds, neutralization depth receives very little effect from a pattern difference, and decreases with increasing displacement rate. Neutralization coefficient of the mortar mixed with silica fume at 10% decreased with the mixing time, and it was possible to suppress the neutralization coefficient to 25% of the case without silica fume addition in a 1020-second mixing. 7 refs., 8 figs., 1 tab.

The measurement of released radionuclides during TIG-Welding and Grinding

Energy Technology Data Exchange (ETDEWEB)

Reichelt, A.; Lehmann, K.-H. [Technical Inspection Agency of Southern Germany (TUEV Sueddeutschland), Subdepartment Environmental Radioactivity, Munich (Germany); Reineking, A. [Isotope Laboratory for Biological and Medical Research, Georg-August-University of Goettingen, Goettingen (Germany); Eder, E. [Government of Bavaria, State Ministry for State Development and Environmental Affairs, Munich (Germany)

2000-05-01

The radiological relevance of the TIG welding using thoriated tungsten electrodes has recently been proved by means of different studies. As a result of this the TUEV Sueddeutschland and the University of Goettingen have carried out special investigations concerning the release of radionuclides during TIG welding. The main emphasis of these investigations were the representativity of various sampling techniques, the influence of various parameters during welding as well as the determination of activity size distributions related to the aerodynamic diameter of the inhaled aerosols. The properties of the tungsten rods are improved through the addition of radioactive thorium. We investigated the radiation exposure by handling with thoriated tungsten welding rods. We investigated the different exposure pathways and determined the specific activity in dependence to the different types of welding rods. By carrying out surveys with the users, we determined the exposure pathways for the individual exposed persons: TIG - hand-welders', TIG 'machine-welders', labourers, other persons. We measured the activity concentration of the breathing air while welding, at grinding the electrodes and by staying in the rooms where usually it's welded. The size distribution of the aerosol-attached activity was determined with several kinds of impactors. The main emphasis was the comparison of the different sampling systems at the measuring of the activity concentration of the breathing air. Selective sampling by impactors: {center_dot} Berner-impactor, stationary {center_dot} Sierra-impactor, stationary {center_dot} Anderson-Imcaktor, stationary {center_dot} Marple-impactor, personal sampler Aerosol sampling by air samplers {center_dot} 5 personal air sampler {center_dot} 2 stationary sampler, ring face {center_dot} 2 stationary sampler, open face Rn-220-Measurements {center_dot} Thoron-monitor Determination of activitys on measuring filters {center_dot} alpha

Characterization of airborne particles generated from metal active gas welding process.

Science.gov (United States)

Guerreiro, C; Gomes, J F; Carvalho, P; Santos, T J G; Miranda, R M; Albuquerque, P

2014-05-01

This study is focused on the characterization of particles emitted in the metal active gas welding of carbon steel using mixture of Ar + CO2, and intends to analyze which are the main process parameters that influence the emission itself. It was found that the amount of emitted particles (measured by particle number and alveolar deposited surface area) are clearly dependent on the distance to the welding front and also on the main welding parameters, namely the current intensity and heat input in the welding process. The emission of airborne fine particles seems to increase with the current intensity as fume-formation rate does. When comparing the tested gas mixtures, higher emissions are observed for more oxidant mixtures, that is, mixtures with higher CO2 content, which result in higher arc stability. These mixtures originate higher concentrations of fine particles (as measured by number of particles by cm(3) of air) and higher values of alveolar deposited surface area of particles, thus resulting in a more severe worker's exposure.

Reducing the cytotoxicity of inhalable engineered nanoparticles via in situ passivation with biocompatible materials.

Science.gov (United States)

Byeon, Jeong Hoon; Park, Jae Hong; Peters, Thomas M; Roberts, Jeffrey T

2015-07-15

The cytotoxicity of model welding nanoparticles was modulated through in situ passivation with soluble biocompatible materials. A passivation process consisting of a spark discharge particle generator coupled to a collison atomizer as a co-flow or counter-flow configuration was used to incorporate the model nanoparticles with chitosan. The tested model welding nanoparticles are inhaled and that A549 cells are a human lung epithelial cell line. Measurements of in vitro cytotoxicity in A549 cells revealed that the passivated nanoparticles had a lower cytotoxicity (>65% in average cell viability, counter-flow) than the untreated model nanoparticles. Moreover, the co-flow incorporation between the nanoparticles and chitosan induced passivation of the nanoparticles, and the average cell viability increased by >80% compared to the model welding nanoparticles. As a more convenient way (additional chitosan generation and incorporation devices may not be required), other passivation strategies through a modification of the welding rod with chitosan adhesive and graphite paste did also enhance average cell viability (>58%). The approach outlined in this work is potentially generalizable as a new platform, using only biocompatible materials in situ, to treat nanoparticles before they are inhaled. Copyright © 2015 Elsevier B.V. All rights reserved.

Dry fumes purifying system using anhydrous baking soda; Procede chimique d`epuration des fumees au bicarbonate de soude anhydre

Energy Technology Data Exchange (ETDEWEB)

Anon.

1998-04-01

UNISYSTEMS has developed the industrial implementation of the chemical process using anhydrous backing soda, patented by SOLVAY, for purifying fumes containing inorganic salts and sulphur oxides as polluting agents. The system can be applied to industrial processes releasing this type of polluting agents in the fumes at a temperature over 160 deg C, as it is specially indicated in purifying fumes coming from ceramic firing kilns. (authors)

Emissions of fluorides from welding processes.

Science.gov (United States)

Szewczyńska, Małgorzata; Pągowska, Emilia; Pyrzyńska, Krystyna

2015-11-01

The levels of fluoride airborne particulates emitted from welding processes were investigated. They were sampled with the patented IOM Sampler, developed by J. H. Vincent and D. Mark at the Institute of Occupational Medicine (IOM), personal inhalable sampler for simultaneous collection of the inhalable and respirable size fractions. Ion chromatography with conductometric detection was used for quantitative analysis. The efficiency of fluoride extraction from the cellulose filter of the IOM sampler was examined using the standard sample of urban air particle matter SRM-1648a. The best results for extraction were obtained when water and the anionic surfactant N-Cetyl-N-N-N-trimethylammonium bromide (CTAB) were used in an ultrasonic bath. The limits of detection and quantification for the whole procedure were 8μg/L and 24μg/L, respectively. The linear range of calibration was 0.01-10mg/L, which corresponds to 0.0001-0.1mg of fluorides per m(3) in collection of a 20L air sample. The concentration of fluorides in the respirable fraction of collected air samples was in the range of 0.20-1.82mg/m(3), while the inhalable fraction contained 0.23-1.96mg/m(3) of fluorides during an eight-hour working day in the welding room. Copyright © 2015. Published by Elsevier B.V.

Pulmonary function abnormalities and airway irritation symptoms of metal fumes exposure on automobile spot welders.

Science.gov (United States)

Luo, Jiin-Chyuan John; Hsu, Kuang-Hung; Shen, Wu-Shiun

2006-06-01

Spot or resistance welding has been considered less hazardous than other types of welding. Automobile manufacturing is a major industry in Taiwan. Spot and arc welding are common processes in this industry. The respiratory effects on automobile spot welders exposed to metal fumes are investigated. The cohort consisted of 41 male auto-body spot welders, 76 male arc welders, 71 male office workers, and 59 assemblers without welding exposure. Inductivity Coupled Plasma Mass Spectrophotometer (ICP-MS) was applied to detect metals' (zinc, copper, nickel) levels in the post-shift urine samples. Demographic data, work history, smoking status, and respiratory tract irritation symptoms were gathered by a standard self-administered questionnaire. Pulmonary function tests were also performed. There were significantly higher values for average urine metals' (zinc, copper, nickel) levels in spot welders and arc welders than in the non-welding controls. There were 4 out of 23 (17.4%) abnormal forced vital capacity (FVC) among the high-exposed spot welders, 2 out of 18 (11.1%) among the low-exposed spot welders, and 6 out of 130 (4.6%) non-welding-exposed workers. There was a significant linear trend between spot welding exposure and the prevalence of restrictive airway abnormalities (P = 0.036) after adjusting for other factors. There were 9 out of 23 (39.1%) abnormal peak expiratory flow rate (PEFR) among high-exposed spot welders, 5 out of 18 (27.8%) among the low-exposed spot welders, and 28 out of 130 (21.5%) non-welding-exposed workers. There was a borderline significant linear trend between spot welding exposure and the prevalence of obstructive lung function abnormalities (P = 0.084) after adjusting for other factors. There was also a significant dose-response relationship of airway irritation symptoms (cough, phlegm, chronic bronchitis) among the spot welders. Arc welders with high exposure status also had a significant risk of obstructive lung abnormalities (PEFR

Experimental study of the combined effects of inhalation of radon daughter products and tobacco smoke

International Nuclear Information System (INIS)

Chameaud, J.; Perraud, R.; Chretien, J.; Masse, R.; Lafuma, J.

1979-01-01

For 10 years, over 500 lung cancers have been induced in rats by inhalations of radon daughter products at various concentrations and cumulated doses. Considering several points and the dose-effect relationship especially, such cancers can be compared with human cancers. This type of experiments, fully mastered, has made it possible to undertake under good conditions the study of the co-carcinogenic effect of various inhaled pollutants such as tobacco smoke. In a first experiment, 100 rats were exposed to a 4000WLM cumulated dose of radon daughter products, knowing that this level induces some 30% of lung cancers. 50 animals were then administered tobacco smoke by inhalation in a fume box during 5 months (350 h.) In the group inhaling radon only, 17 cancers appeared; in the radon -tobacco group 32 cancers bigger and more invasive were observed. Under the same conditions, tobacco smoke was inhaled by rats previously exposed to lower doses of radon daughter products (2 groups of 30 rats, 500 and 100 WLM respectively). Again, the number of cancers observed was higher that the number of cancers expected if the rats had inhaled radon only. This co-carcinogenic and potentiating action of tobacco was clearly demonstrated. Further experiments are considered in order to determine the processes involved

Radiological impact assessment of arc welding supplies rutile

International Nuclear Information System (INIS)

Rozas Guinea, S.; Herranz Soler, M.; Perez Marin, C.; Idoeta Hermandorena, R.; Alegria gutierrez, N.; Nunez-Lagos Rogla, R.; Legarda Ibanez, F.

2013-01-01

Consumables for welding containing rutile, the coating of the electrode or the filling of tubular thread, are the most widely used and also the most radioactive since the rutile is a mineral containing traces of natural radionuclides, and is therefore considered Normal Occurring Radioactive Material (NORM). As these electrodes and wire are consumed, small particles, aerosols and gases are emitted to the atmosphere of work, and may be inhaled by the welder. Therefore, and also according to the current regulatory framework and work carried out previously by the author on the radiological impact of the process of manufacture and storage of coated rutile electrodes, the objectives are: 1Calcular the internal dose for inhalation during two types of welding, one with electrodes coated and the other with thread. 2 calculate the external dose due to the deposition of particles in the work environment, slag and the immersion of the soldering iron in the cloud of smoke. 3 to assess the radiological impact. (Author)

[Analysis on oil fume particles in catering industry cooking emission].

Science.gov (United States)

Tan, De-Sheng; Kuang, Yuan-Cheng; Liu, Xin; Dai, Fei-Hong

2012-06-01

By measuring the particulate matter of oil fume which is over 10 microm or below 10 microm separately and using microradiography and Electrical Low Pressure Impactor (ELPI), it is found out the distributing characteristic of oil fume particles in catering industry cooking emission. The result shows that the diameter of the oil fume particles which was sedimentated in the kitchen is between 10-400 microm, the concentration peak value is between 10-100 microm. The diameter of oil fume aerosol is mostly smaller than 1 microm, while the concentration peak value is between 0.063-0.109 microm. In addition, the mass concentration peak value is between 6.560-9.990 microm. Through the analysis to the physical characteristics of oil fume from catering industry cooking emissions, the eigenvalue of the oil fume has been found and the feature matter for monitoring the oil fume has been discovered to provide a reasonable standard for controlling and monitoring the catering industry cooking emission.

Generation rate of carbon monoxide from CO2 arc welding.

Science.gov (United States)

Ojima, Jun

2013-01-01

CO poisoning has been a serious industrial hazard in Japanese workplaces. Although incomplete combustion is the major cause of CO generation, there is a risk of CO poisoning during some welding operations. The aim of the present study was to evaluate the generation rate of CO from CO2 arc welding under controlled laboratory conditions and estimate the ventilation requirements for the prevention of CO poisoning. Bead on plate welding was carried out with an automatic welding robot on a rolled steel base metal under several conditions. The concentration of emitted CO from the welding was measured by a real-time CO monitor in a well-ventilated laboratory that was free from ambient CO contamination. The generation rate of CO was obtained from the three measurements-the flow rate of the welding exhaust gas, CO concentration in the exhaust gas and the arcing time. Then the ventilation requirement to prevent CO poisoning was calculated. The generation rate of CO was found to be 386-883 ml/min with a solid wire and 331-1,293 ml/min with a flux cored wire respectively. It was found that the CO concentration in a room would be maintained theoretically below the OSHA PEL (50 ppm) providing the ventilation rate in the room was 6.6-25.9 m3/min. The actual ventilation requirement was then estimated to be 6.6-259 m3/min considering incomplete mixing. In order to prevent CO poisoning, some countermeasures against gaseous emission as well as welding fumes should be taken eagerly.

IMPROVEMENT OF EXPANSIVE SOIL BY USING SILICA FUME

Directory of Open Access Journals (Sweden)

Kawther Y. AL-Soudany

2018-01-01

Full Text Available Expansive soils are characterized by their considerable volumetric deformations representing a serious challenge for the stability of the engineering structures such as foundations. Consequently, the measurements of swelling properties, involving swelling and swell pressure, become extremely important in spite of their determination needs a lot of time with costly particular equipment. Thus, serious researches attempts have been tried to remedy such soils by means of additives such as cement, lime, steel fibers, stone dust, fly ash and silica fume. In this research the study of silica fume has studied to treatment expansion soil, the clay soil was brought from Al-Nahrawan in Baghdad. The soil selected for the present investigation prepared in laboratory by mixing natural soil with different percentages of bentonite (30, 50 and 70% by soil dry weight. The test program included the effect of bentonite on natural soil then study the effect of silica fume (SF on prepared soil by adding different percentage of silica fume (3, 5, and 7 by weight to the prepared soils and the influence of these admixtures was observed by comparing their results with those of untreated soils (prepared soils. The results show that both liquid limit and plasticity index decreased with the addition of silica fume, while the plastic limit is increase with its addition. As well as, a decrease in the maximum dry unit weight with an increase in the optimum water contents have been obtained with increasing the percentage of addition of the silica fume. It is also observed an improvement in the free swell, swelling pressure by using silica fume. It can be concluded that the silica fume stabilization may be used as a successful way for the treatment of expansive clay.

Analysis of polycyclic aromatic hydrocarbons in cooking oil fumes.

Science.gov (United States)

Li, S; Pan, D; Wang, G

1994-01-01

Various samples of cooking oil fumes were analyzed to an effort to study the relationship between the high incidence of pulmonary adenocarcinoma in Chinese women and cooking oil fumes in the kitchen. Polycyclic aromatic hydrocarbons (PAHs) in samples of cooking oil fumes were extracted, chromatographed, and measured by fluorescence spectrophotometer. The samples included oil fumes from three commercial cooking oils and fumes from three catering shops. All samples contained benzo(a)pyrene (BaP) and dibenzo (a,h)anthracene (DBahA). In addition, the concentration of DBahA was 5.7 to 22.8 times higher than that of BaP in the fume samples. Concentrations of BaP and DBahA were, respectively, 0.463 and 5.736 micrograms/g in refined vegetable oil, 0.341 and 3.725 micrograms/g in soybean oil, and 0.305 and 4.565 micrograms/g in vegetable oil. Investigation of PAH concentrations at three catering shops showed that the level of BaP at a Youtiao (deep-fried twisted dough sticks) shop was 4.18 micrograms/100 m3, 2.28 micrograms/100 m3 at a Seqenma (candied fritters) workshop, and 0.49 micrograms/100 m3 at a kitchen of a restaurant; concentrations of DBahA were 33.80, 14.41, and 3.03 micrograms/100 m3, respectively. The high concentration of carcinogens, such as BaP and DBahA, in cooking oil fumes might help explain why Chinese women, who spend more time exposed to cooking oil fumes than men, have a high incidence of pulmonary adenocarcinoma.

Urinary neutrophil gelatinase-associated lipocalin is associated with heavy metal exposure in welding workers.

Science.gov (United States)

Chuang, Kai-Jen; Pan, Chih-Hong; Su, Chien-Ling; Lai, Ching-Huang; Lin, Wen-Yi; Ma, Chih-Ming; Ho, Shu-Chuan; Bien, Mauo-Ying; Chen, Cheng-Hsien; Chuang, Hsiao-Chi

2015-12-17

Metals cause nephrotoxicity with acute and/or chronic exposure; however, few epidemiological studies have examined impacts of exposure to metal fumes on renal injury in welding workers. In total, 66 welding workers and 12 office workers were recruited from a shipyard located in southern Taiwan. Urine samples from each subject were collected at the beginning (baseline) and end of the work week (1-week exposure). Personal exposure to PM2.5 was measured. The 8-h mean PM2.5 was 50.3 μg/m(3) for welding workers and 27.4 μg/m(3) for office workers. iTRAQs coupled with LC-MS/MS were used to discover the pathways in response to welding PM2.5 in the urine, suggesting that extracellular matrix (ECM)-receptor interactions are a critical mechanism. ECM-receptor interaction-related biomarkers for renal injury, kidney injury molecule (KIM)-1 and neutrophil gelatinase-associated lipocalin (NGAL), were significantly elevated in welding workers post-exposure, as well as were urinary Al, Cr, Mn, Fe, Co, and Ni levels. NGAL was more significantly associated with Al (r = 0.737, p welding PM2.5 exposure. Nephrotoxicity (e.g., renal tubular injury) may be an emerging concern in occupational health.

Biological effects of chronic inhalation of coal mine dust and/or diesel engine exhaust in rodents

International Nuclear Information System (INIS)

Karagianes, M.T.; Palmer, R.F.; Stuart, B.O.; Zwicker, G.M.; Teats, D.

1979-01-01

Rats were killed at 4, 8, 16, and 20 mo after the start of exposures to inhaled high-CWP bituminous coal mine dust separately and combined with unscrubbed exhaust fumes from a diesel engine operated under load-rpm cycling. General health and hematologic parameters were normal. Lung lesions and accumulations of particulate matter increased with length and type of exposure; however, no animals have developed lung tumors or precancerous tissue changes up to 16 mo postexposure

Reduction of fume damage in forests: report on the symposium on fume damage held in Tharandt from 30th September to 2nd October 1965

Energy Technology Data Exchange (ETDEWEB)

Daessler, H G; Ranft, H

1967-01-01

Summaries are presented of 15 papers, including: extent of variation in fume resistance in Larix and problems of breeding for resistance (Schoenbach); results of research on fume damage on experimental areas in E. Germany (H. Enderlin) (noting differences in resistance to SO/sub 2/ damage of various species of Picea, Pinus, and Abies, varieties of Pseudotsuga taxifolia and provenances of Pinus contorta and Larix spp., effect of fertilizers on resistance, and mass selection of resistant planting stock in practice); resistance of Pinus omorika to fume damage (K.F. Wentzel); chemical and physiological studies on the metabolism of the assimilation organs of conifers affected by SO/sub 2/ (S. Boertitz); basic physiological and phenological studies on the preliminary selection of conifers for SO/sub 2/ resistance (M. Vogl); fertilizer trials in fume-damaged pine stands on Dueben Heath (H. Krauss); insect pests on young pine stands in fume-damaged regions in Poland (Z. Sierpinski); birch and alder pests in industrial regions (Z. Schnaider); management of young fume-damaged spruce stands (E. Pelz); effect of fumes from the potash industry on forest stands in East Germany (E. Ewert); the distribution of injurious substances in leaves (G. Halbwachs); emission of SO/sub 2/ absorbed by spruce needles (J. Materna); and estimating fume damage expected near future power stations (H. Lux).

Study of radon transport through concrete modified with silica fume

International Nuclear Information System (INIS)

Chauhan, R.P.; Kumar, Amit

2013-01-01

The concentration of radon in soil usually varies between a few kBq/m 3 and tens or hundreds of kBq/m 3 depending upon the geographical region. This causes the transport of radon from the soil to indoor environments by diffusion and advection through the pore space of concrete. To reduce indoor radon levels, the use of concrete with low porosity and a low radon diffusion coefficient is recommended. A method of reducing the radon diffusion coefficient through concrete and hence the indoor radon concentration by using silica fume to replace an optimum level of cement was studied. The diffusion coefficient of the concrete was reduced from (1.63 ± 0.3) × 10 −7 to (0.65 ± 0.01) × 10 −8 m 2 /s using 30% substitution of cement with silica fume. The compressive strength of the concrete increased as the silica-fume content increased, while radon exhalation rate and porosity of the concrete decreased. This study suggests a cost-effective method of reducing indoor radon levels. -- Highlights: • Radon diffusion study through silica fume modified concrete was carried out. • Radon diffusion coefficient of concrete decreased with increase of silica fume contents. • Compressive strength increased with increase of silica fume. • Radon exhalation rates and porosity of samples decreased with addition of silica fume. • Radon diffusion coefficient decreased to 2.6% by 30% silica fume substitution

Frequency distribution of gastro esophageal reflux disease in inhalation injury: A historical cohort study.

Science.gov (United States)

Karbasi, Ashraf; Aliannejad, Rasoul; Ghanei, Mostafa; Sanamy, Mehran Noory; Alaeddini, Farshid; Harandi, Ali Amini

2015-07-01

There is no data on the prevalence and the association of gastro esophageal reflux disease (GERD) with toxic fume inhalation. Therefore, we aimed to evaluate the frequency distribution of GERD symptoms among the individuals with mild respiratory disorder due to the past history of toxic fume exposure to sulfur mustard (SM). In a historical cohort study, subjects were randomly selected from 7000 patients in a database of all those who had a history of previous exposure to a single high dose of SM gas during war. The control group was randomly selected from adjacent neighbors of the patients, and two healthy male subjects were chosen per patient. In this study, we used the validated Persian translation of Mayo Gastroesophageal Reflux Questionnaire to assess the frequency distribution of reflux disease. Relative frequency of GERD symptoms, was found to be significantly higher in the inhalation injury patients with an odds ratio of 8.30 (95% confidence interval [CI]: 4.73-14.55), and after adjustment for cigarette smoking, tea consumption, age, and body mass index, aspirin and chronic cough the odds ratio was found to be 4.41 (95% CI: 1.61-12.07). The most important finding of our study was the major GERD symptoms (heartburn and/or acid regurgitation once or more per week) among the individuals with the past history of exposure to SM toxic gas is substantially higher (4.4-fold) than normal populations.

Interlaboratory comparison on 137Cs activity concentration in fume dust

International Nuclear Information System (INIS)

Tzika, Faidra; Hult, Mikael; Burda, Oleksiy; Arnold, Dirk; Sibbens, Goedele; Caro Marroyo, Belén; Gómez–Mancebo, Maria Belén; Peyrés, Virginia; Moser, Hannah; Ferreux, Laurent; Šolc, Jaroslav; Dryák, Pavel; Fazio, Aldo; Luca, Aurelian; Vodenik, Branko; Reis, Mario

2015-01-01

A comparison was conducted, between 11 European National Metrology Institutes and EC-JRC, on measurement of 137 Cs activity concentration in fume dust. As test material an activity standard produced from real contaminated fume dust was used. The standard material consisted of 13 cylindrical samples of compressed fume dust. The material contained 137 Cs and 60 Co of reference activity concentrations of (9.72±0.10) Bq/g and (0.450±0.018) Bq/g, respectively, for the reference date of 1 June 2013, determined using the comparison results. The organization and results of the intercomparison, as well as the process of obtaining reliable reference values are presented. - Highlights: • A European comparison was conducted on measurement of 137 Cs activity in fume dust. • Participants used high resolution gamma ray spectrometry. • Efficiency calibration included Monte Carlo, numerical and experimental methods. • Reference 137 Cs and 60 Co activity concentrations in the fume dust were determined. • A new traceable activity standard of fume dust matrix is available to end-users.

Effective dose in SMAW and FCAW welding processes using rutile consumables.

Science.gov (United States)

Herranz, M; Rozas, S; Idoeta, R; Alegría, N

2014-03-01

The shielded metal arc welding (SMAW) and flux cored arc welding (FCAW) processes use covered electrodes and flux cored wire as consumables. Among these consumables, ones containing rutile are the most widely used, and since they have a considerable natural radioactive content, they can be considered as NORM (naturally occurring radioactive material). To calculate the effective dose on workers during their use in a conservative situation, samples of slag and aerosols and particles emitted or deposited during welding were taken and measured by gamma, alpha and beta spectrometry. An analytical method was also developed for estimating the activity concentration of radionuclides in the inhaled air. (222)Rn activity concentration was also assessed. With all these data, internal and external doses were calculated. The results show that external doses are negligible in comparison with internal ones, which do not exceed 1 mSv yr(-1), either in this conservative situation or in any other more favourable one. Radionuclides after Rn in the radioactive natural series are emitted at the same activity concentration to the atmosphere, this being around 17 times higher than that corresponding to radionuclides before Rn. Taking into account these conclusions and the analytical method developed, it can be concluded that one way to assess the activity concentration of natural radionuclides in inhaled air and hence effective doses could be the early gamma-ray spectrometry of aerosols and particles sampled during the welding process.

Modelling of occupational exposure to inhalable nickel compounds.

Science.gov (United States)

Kendzia, Benjamin; Pesch, Beate; Koppisch, Dorothea; Van Gelder, Rainer; Pitzke, Katrin; Zschiesche, Wolfgang; Behrens, Thomas; Weiss, Tobias; Siemiatycki, Jack; Lavoué, Jerome; Jöckel, Karl-Heinz; Stamm, Roger; Brüning, Thomas

2017-07-01

The aim of this study was to estimate average occupational exposure to inhalable nickel (Ni) using the German exposure database MEGA. This database contains 8052 personal measurements of Ni collected between 1990 and 2009 in adjunct with information on the measurement and workplace conditions. The median of all Ni concentrations was 9 μg/m 3 and the 95th percentile was 460 μg/m 3 . We predicted geometric means (GMs) for welders and other occupations centered to 1999. Exposure to Ni in welders is strongly influenced by the welding process applied and the Ni content of the used welding materials. Welding with consumable electrodes of high Ni content (>30%) was associated with 10-fold higher concentrations compared with those with a low content (exposure levels (GMs ≥20 μg/m 3 ) were observed in gas metal and shielded metal arc welders using welding materials with high Ni content, in metal sprayers, grinders and forging-press operators, and in the manufacture of batteries and accumulators. The exposure profiles are useful for exposure assessment in epidemiologic studies as well as in industrial hygiene. Therefore, we recommend to collect additional exposure-specific information in addition to the job title in community-based studies when estimating the health risks of Ni exposure.

Comparison of Effect of Metakaolin and silica Fume on Fly Ash Concrete Performance

Directory of Open Access Journals (Sweden)

Hou Yunfen

2016-01-01

Full Text Available Silica fume is a common mineral admixture used in HSC and HPC, but being its high price and shrinkage in concrete, its usage is under restrictions. As a new mineral admixture, metakaolin gets more and more attention. In order to compare the difference between silica fume and metakaolin, the effects of metakaolin and silica fume on concrete workability, compressive strength, and chloride penetration resistance are studied. It shows that incorporating with fly ash together, silica fume reduces the slump extension, but metakaolin can increases it; silica fume can increases early strength more than metakaolin can, but it isn’t useful for later and long-time strength; metakaolin not only can increase early strength, but also can improve long-time strength. Silica fume and metakaolin can increase the chloride penetration resistance. As a new mineral additive, metakaolin can play a role in concrete which silica fume does, even much better than silica fume.

Silica fume effect on retention characteristics of portland cement for uranium (VI)

International Nuclear Information System (INIS)

Tan Hongbin; Ma Xiaoling; Li Yuxiang

2005-01-01

With simulated groundwater as leachant, the retention capabilities of the portland cement, which contains different amount of silica fume, are investigated under 25 degree C and 42 days. The results indicate that silica fume can improve the retention capabilities of portland cement for uranium. When the cement contains 15% silica fume, the diffusion coefficient is 7 x 10 -3 cm 3 · -1 . It is only 5.5% of the cement without containing fume. (authors)

Acute respiratory effects and biomarkers of inflammation due to welding-derived nanoparticle aggregates.

Science.gov (United States)

Dierschke, Katrin; Isaxon, Christina; Andersson, Ulla B K; Assarsson, Eva; Axmon, Anna; Stockfelt, Leo; Gudmundsson, Anders; Jönsson, Bo A G; Kåredal, Monica; Löndahl, Jakob; Pagels, Joakim; Wierzbicka, Aneta; Bohgard, Mats; Nielsen, Jörn

2017-07-01

Welders are exposed to airborne particles from the welding environment and often develop symptoms work-related from the airways. A large fraction of the particles from welding are in the nano-size range. In this study we investigate if the welders' airways are affected by exposure to particles derived from gas metal arc welding in mild steel in levels corresponding to a normal welding day. In an exposure chamber, 11 welders with and 10 welders without work-related symptoms from the lower airways and 11 non-welders without symptoms, were exposed to welding fumes (1 mg/m 3 ) and to filtered air, respectively, in a double-blind manner. Symptoms from eyes and upper and lower airways and lung function were registered. Blood and nasal lavage (NL) were sampled before, immediately after and the morning after exposure for analysis of markers of oxidative stress. Exhaled breath condensate (EBC) for analysis of leukotriene B4 (LT-B4) was sampled before, during and immediately after exposure. No adverse effects of welding exposure were found regarding symptoms and lung function. However, EBC LT-B4 decreased significantly in all participants after welding exposure compared to filtered air. NL IL-6 increased immediately after exposure in the two non-symptomatic groups and blood neutrophils tended to increase in the symptomatic welder group. The morning after, neutrophils and serum IL-8 had decreased in all three groups after welding exposure. Remarkably, the symptomatic welder group had a tenfold higher level of EBC LT-B4 compared to the two groups without symptoms. Despite no clinical adverse effects at welding, changes in inflammatory markers may indicate subclinical effects even at exposure below the present Swedish threshold limit (8 h TWA respirable dust).

When are fume-cupboards necessary in hospital radioisotope laboratories

Energy Technology Data Exchange (ETDEWEB)

Birks, J L [Singleton Hospital, Swansea (UK)

1976-06-01

Suggestions are made for procedures likely to require the provision of efficient fume-cupboards in hospital radioisotope laboratories. All such departments undertaking in vivo radioisotope procedures will require a supply of sterile materials, but only some of these will also require a fume-cupboard, since the use of a relatively inexpensive aseptic cabinet, without air flow and exhaust system, may suffice for such procedures as the labelling of blood cells or plasma. Efficient fume-cupboards may be required in hospital laboratories that are routinely concerned with the elution of generators of isotopes such as /sup 99/Tcsup(m) and /sup 113/Insup(m), the sterilization of radiopharmaceuticals (e.g. technetium-sulphur colloid) requiring the use of a pressure cooker, and the storage and handling of therapeutic quantities of /sup 131/I. Copious general ventilation of isotope rooms may be preferable to the too frequent incorporation of unnecessary fume-cupboards.

Effects of nitrous fumes upon the lung

Energy Technology Data Exchange (ETDEWEB)

Muhar, F; Raber, A

1974-01-01

After a thorough discussion of the accidental poisoning of 34 workers by large amounts of nitrous fumes in an Austrian chemical plant producing artificial fertilizer and its effects on the lung along with therapeutical measures taken, the chronic effects of long-term exposure to nitrous gases are reviewed. Nitrous gases are a mixture of various oxidation states of nitrogen such as nitric oxide, nitrogen dioxide, N/sub 2/O/sub 4/, and nitric anhydride plus vapors of nitrous and nitric acid. The individual components of the gas mixture change in dependence on the ambient temperature and the humidity. A different mixture of nitrous gases develops, therefore, at welding operations, blasts, in the chemical industry, in the glass industry, at the production of fertilizer, in the exhausts of combustion engines, and in smoking of cigarettes. The irritations caused by nitrous gases on mucous tissue increase with rising relative humidity. The presence of NO ameliorates the toxic effect of NO/sub 2/. Oil mists protect against the effects of nitrous gases. The addition of sulfur dioxide is supposed to reduce the toxicity of nitrous gases, provided the SO/sub 2/ concentration is considerably higher than the concentration of nitrous gases. Exposure of rats and mice to concentrations of less than 1 ppm nitrous gases caused structural changes in the lung similar to pulmonary edema in humans.

EFFECTS OF FIRE FUMES ON ALMOND SAFETY AND QUALITY

Directory of Open Access Journals (Sweden)

Amanda Ramírez-Gandolfo

2011-08-01

Full Text Available A fire originated and burnt two cold chambers; the present study focused on almonds stored in adjacent chambers (4, 5, 6 and 13 and evaluated both their food safety and quality. Testing for polycyclic aromatic hydrocarbons, polychlorinated dibenzo-p-dioxins and dibenzofurans was carried out in affected facilities, packaging and almonds. Experimental results proved that fire fumes did not reach chambers 4-6, but traces were found in bin packaging of chamber 13; thus, packaging from this chamber were changed. Concentrations of benzo(apyrene were low enough to prove that fire fumes did not get in contact with the stored almonds. Later, only volatile compounds typical of nuts were identified in both raw and toasted almonds. Finally, a trained panel concluded that no sensory signal of fumes reaching almonds was found. This manuscript could be taken as a model protocol to establish whether fire fumes have reached and affected the safety and/or quality of foods. This information will be especially useful for insurance companies.

Fatal acute poisoning from massive inhalation of gasoline vapors: case report and comparison with similar cases.

Science.gov (United States)

Papi, Luigi; Chericoni, Silvio; Bresci, Francesco; Giusiani, Mario

2013-03-01

We describe a case of an acute lethal poisoning with hydrocarbons resulting from massive accidental inhalation of gasoline vapors. The victim, a 50-year-old man was found unconscious inside a control room for the transport of unleaded fuel. Complete autopsy was performed and showed evidence of congestion and edema of the lungs. Toxicological investigation was therefore fundamental to confirm exposure to fumes of gasoline. Both venous and arterial blood showed high values of volatiles in particular for benzene (39.0 and 30.4 μg/mL, respectively), toluene (23.7 and 20.4 μg/mL), and xylene isomers (29.8 and 19.3 μg/mL). The relatively low values found in the lungs are consistent with the fact that the subject, during the rescue, underwent orotracheal intubation followed by resuscitation techniques, while the low concentrations for all substances found in urine and kidneys could point to a death that occurred in a very short time after first contact with the fumes of gasoline. © 2012 American Academy of Forensic Sciences.

[Emission Characteristics of Water-Soluble Ions in Fumes of Coal Fired Boilers in Beijing].

Science.gov (United States)

Hu, Yue-qi; Ma, Zhao-hui; Feng, Ya-jun; Wang, Chen; Chen, Yuan-yuan; He, Ming

2015-06-01

Selecting coal fired boilers with typical flue gas desulfurization and dust extraction systems in Beijing as the study objects, the issues and characteristics of the water-soluble ions in fumes of coal fired boilers and theirs influence factors were analyzed and evaluated. The maximum mass concentration of total water-soluble ions in fumes of coal fired boilers in Beijing was 51.240 mg x m(-3) in the benchmark fume oxygen content, the minimum was 7.186 mg x m(-3), and the issues of the water-soluble ions were uncorrelated with the fume moisture content. SO4(2-) was the primary characteristic water-soluble ion for desulfurization reaction, and the rate of contribution of SO4(2-) in total water-soluble ions ranged from 63.8% to 81.0%. F- was another characteristic water-soluble ion in fumes of thermal power plant, and the rate of contribution of F- in total water-soluble ions ranged from 22.2% to 32.5%. The fume purification technologies significantly influenced the issues and the emission characteristics of water-soluble ions in fumes of coal fired boilers. Na+ was a characteristic water-soluble ion for the desulfurizer NaOH, NH4+ and NO3+ were characteristic for the desulfurizer NH4HCO3, and Mg2+ was characteristic for the desulfurizer MgO, but the Ca2+ emission was not increased by addition of the desulfurizer CaO or CaCO3 The concentrations of NH4+ and NO3- in fumes of thermal power plant were lower than those in fumes of industrial or heating coal fired boilers. The form of water-soluble ions was significantly correlated with fume temperature. The most water-soluble ions were in superfine state at higher fume temperature and were not easily captured by the filter membrane.

Environmental exposure to cooking oil fumes and cervical intraepithelial neoplasm

International Nuclear Information System (INIS)

Wu, M.-T.; Lee, L.-H.; Ho, C.-K.; Wu, S.-C.; Lin, L.-Y.; Cheng, B.-H.; Liu, C.-L.; Yang, C.-Y.; Tsai, H.-T.; Wu, T.-N.

2004-01-01

The fumes from cooking oil, similar to cigarette smoke, contain numerous carcinogens such as polycyclic aromatic hydrocarbons, aromatic amines, nitro-polycyclic aromatic hydrocarbons, etc. In this study, we examined the association between exposure to cooking oil fumes and the risk of cervical intraepithelial neoplasm. The study population in this nested case-control study consisted of women above the age of 19 years living in Chia-Yi County, located in the southwestern Taiwan, who had received pap smear screening between October, 1999, and December, 2000 (n=32,466). The potential cases were women having lesions greater than cervical intraepithelium neoplasm II (≥CIN2) reconfirmed by cervical biopsy (n=116). The potential controls (case: control=1:2) were age-matched (±2 years) and residence-matched women who had normal pap smears within 6 months of the cases. In total, 100 cases and 197 controls were completely interviewed by public health nurses about cooking methods, ventilation, and other potential risk factors. Women who cooked at home in a kitchen (n=269) without the presence of a fume extractor at least once a week between the ages of 20 and 40 had a 2.29 times higher risk [95% confidence interval (CI)=1.08-4.87] of developing cervical intraepithelial neoplasm than those who did not cook once a week in such a kitchen during the same age span, after adjusting for other potential confounders. This finding was further strengthened by the finding that women who did not use the fume extractors had a 2.47 times higher risk (95% CI=1.15-5.32) of developing cervical intraepithelial neoplasm than women who cooked in kitchens with fume extractors that were always switched on while cooking. We also found a joint protective effect of fume extractor use among women older than 40 years (n=202) if they used the extractors during both age spans of their lives, ages 20-40 and >40 years. Comparing our findings on women more than 40 years old who used fume extractors during

Effect of Silica fume and superplasticizer on steel-concrete bond

International Nuclear Information System (INIS)

Esfahani, M. R.

2001-01-01

This paper presents a study on the influence of silica fume and super plasticizer on bond strength. The study included tests of fifty short length pull-out specimens in five series. The effect of silica fume and super plasticizer on bond strength was evaluated separately by tests of specimens made of concretes with similar strengths but different admixtures. Test results showed that the addition of silica fume in the concrete mixture had not a negative effect on bond strength. Also, there was not a considerable decrease in bond strength of specimens made of concrete with super plasticizer. Comparing the measured bond strengths normalized with respect to the square root of the concrete compressive strength, it was seen that the normalized bond strength increased with the concrete strength. this result agrees with the model previously proposed by the author for local bond strength. For the specimens made of high strength concrete including silica fume and super plasticizer, the normalized bond strength did not increase with the concrete strength

FABRICATION AND CHARACTERIZATION OF POLYIMIDE/POLYETHERSULFONE-FUMED SILICA MIXED MATRIX MEMBRANE FOR GAS SEPARATION

Directory of Open Access Journals (Sweden)

A. F. Ismail

2012-01-01

Full Text Available This study is performed primarily to investigate the feasibility of fumed silica as inorganic material towards gas separation performance of mixed matrix membrane. In this study, polyimide/polyethersulfone (PES-fumed silica mixed matrix membranes were casted using dry/wet technique. The results from the FESEM, DSC and FTIR analysis confirmed that the structure and physical properties of membrane is influenced by inorganic filler. FESEM’s cross-section view indicated good compatibility between polymer and fumed silica for all of range fumed silica used in this study. The gas separation performance of the mixed matrix membranes with fumed silica were relatively higher compared to that of the neat PI/PES membrane. PI/PES-fumed silica 5 wt% yielded significant selectivity enhancement of 7.21 and 40.47 for O2/N2, and CO2/CH4, respectively.

Occupational exposure to diesel exhaust fumes

International Nuclear Information System (INIS)

Wheatley, A. D.; Sadhra, S.

2004-01-01

There is currently no OEL for diesel fumes in the UK. This study reports parallel measurements of airborne levels of diesel fume pollutants in nine distribution depots where diesel powered fork-lift trucks (FLTs) were in use. Correlations between individual pollutants are assessed as well as their spatial distribution. Samples were collected on board FLTs and at background positions at nine distribution depots. Substances measured and the range of exposures by site were: respirable dust (n = 76) GM ≤ 80-179 μg/m 3 ; elemental carbon (n = 79) GM = 7-55 μg/m 3 ; organic carbon (n = 79) GM 11-69 μg/m 3 ; ultrafine particles (n = 17) range = 58-231 x 10 3 particles/cm 3 ; selected particulate phase polycyclic aromatic hydrocarbons (PAHs) (n - 14) range = 6-37 ng/m 3 . In addition, a tracer method based on ultrafine particle measurements was used to estimate the spatial distribution of total carbon and PAHs at the sites monitored. The spatial distribution was found to be reasonably uniform. Major diesel fume aerosol components were, in general, well correlated (r = 0.62-0.97). CO 2 measurements were also made and found to be below the HSE guideline of 1000 p.p.m., with most levels below 600 p.p.m. (Author)

Occupational medicine effects of carbon monoxide

Energy Technology Data Exchange (ETDEWEB)

Coombs, W.M. [South African Society of Occupational Medicine (South Africa)

1998-10-01

Carbon monoxide can affect the body if it is inhaled or if liquid carbon monoxide comes in contact with the eyes or skin. The effects of overexposure are discussed and a brief explanation of the toxicological effects of CO given. Methods of control of CO from common operations (exhaust fumes of internal combustion engines, the chemical industry and foundries, welding, mines or tunnels, fire damp explosions, industrial heating) are by local exhaust ventilation or use of a respiratory protective device. The South African hazardous chemical substance regulation NO. R. 1179 of 25 August 1995 stipulates maximum safe levels of CO concentration. 4 refs., 1 photo.

A comparison between atmospheric/humidity and vacuum cyanoacrylate fuming of latent fingermarks.

Science.gov (United States)

Farrugia, Kevin J; Fraser, Joanna; Friel, Lauren; Adams, Duncan; Attard-Montalto, Nicola; Deacon, Paul

2015-12-01

A number of pseudo-operational trials were set up to compare the atmospheric/humidity and vacuum cyanoacrylate fuming processes on plastic carrier bags. The fuming processes were compared using two-step cyanoacrylate fuming with basic yellow 40 (BY40) staining and a one-step fluorescent cyanoacrylate fuming, Lumicyano 4%. Preliminary work using planted fingermarks and split depletions were performed to identify the optimum vacuum fuming conditions. The first pseudo-operational trial compared the different fuming conditions (atmospheric/humidity vs. vacuum) for the two-step process where an additional 50% more marks were detected with the atmospheric/humidity process. None of the marks by the vacuum process could be observed visually; however, a significant number of marks were detected by fluorescence after BY40 staining. The second trial repeated the same work in trial 1 using the one-step cyanoacrylate process, Lumicyano at a concentration of 4%. Trial 2 provided comparable results to trial 1 and all the items were then re-treated with Lumicyano 4% at atmospheric/humidity conditions before dyeing with BY40 to provide the sequences of process A (Lumicyano 4% atmospheric-Lumicyano 4% atmospheric-BY40) and process B (Lumicyano 4% vacuum-Lumicyano 4% atmospheric-BY40). The number of marks (visual and fluorescent) was counted after each treatment with a substantial increase in the number of detected marks in the second and third treatments of the process. The increased detection rate after the double Lumicyano process was unexpected and may have important implications. Trial 3 was performed to investigate whether the amount of cyanoacrylate and/or fuming time had an impact on the results observed in trial 2 whereas trial 4 assessed if the double process using conventional cyanoacrylate, rather than Lumicyano 4%, provided an increased detection rate. Trials 3 and 4 confirmed that doubling the amount of Lumicyano 4% cyanoacrylate and fuming time produced a lower

Effect of petroleum products inhalation on some haematological indices of fuel attendants in Calabar metropolis, Nigeria.

Science.gov (United States)

Okoro, A M; Ani, E J; Ibu, J O; Akpogomeh, B A

2006-01-01

The Haematotoxic implications of exposure to petroleum fumes through inhalation in human subjects were investigated. A total of 400 subjects (200 males and 200 females) aged between 18-30 years participated. Each gender was further categorized into two groups of 100 each for control and test, respectively. The test group was again subdivided into test 1 (T1) and test 2 (T2) in both sexes. T1 subjects were exposed to petroleum fumes for two years and below while T2 subjects were exposed for more than two years. Samples of blood were collected daily and subjected to haematological analysis. The results obtained showed that in males and females, red blood cell counts (10(6) /mm3) was significantly [P < 0.001] decreased in T1 (4.4 +/- 0.13) and T2 (3.85 +/- 0.07) compared to control (4.76 +/- 0.01). White blood cell counts, haematocrit, haemoglobin concentration and mean corpusclular haemoglobin concentration (MCHC) were significantly [P < 0.01] decreased in both sexes of test groups when compared with control. There was also a significant [P < 0.001] decrease in mean corpuscular haemoglobin (MCH) and mean corpuscular volume (MCV) in test 2 males compared with control. Most subjects exposed for longer than two years (T2) had significantly [P < 0.001] lower values of red blood cell count, haemoglobin concentration and haematocrit than those exposed for less than two years. The odds/odds ratio that a subject would become anaemic progressively rose from less than 1 in the control to greater than 1 or infinity on exposure to petroleum fumes. These results indicate that the petroleum fumes cause a reduction in haematological indices which worsens with prolonged exposure.

Investigations on the tensile strength of high performance concrete incorporating silica fume

International Nuclear Information System (INIS)

Santanu Bhanja; Bratish Sengupta

2005-01-01

Though the literature is rich in reporting on silica fume concrete the technical data on tensile strength is quite limited. The present paper is directed towards developing a better understanding on the isolated contribution of silica fume on the tensile strengths of High Performance Concrete. Extensive experimentation was carried out over water-binder ratios ranging from 0.26 to 0.42 and silica fume binder ratios from 0.0 to 0.3. For all the mixes compressive, flexural and split tensile strengths were determined at 28 days. The results of the present investigation indicate that silica fume incorporation results in significant improvements in the tensile strengths of concrete. It is also observed that the optimum replacement percentage, which led to maximization of strength, is not a constant one but depends on the water- cementitious material ratio of the mix. Compared to split tensile strengths, flexural strengths have exhibited greater percentage gains in strength. Increase in split tensile strength beyond 15% silica fume replacement is almost insignificant whereas sizeable gains in flexural tensile strength have occurred even up to 25% replacements. For the present investigation transgranular failure of concrete was observed which indicate that silica fume incorporation results in significant improvements in the strength of both paste and transition zone. (authors)

Danish Investigations on Silica Fume Concretes at Elevated Temperatures

DEFF Research Database (Denmark)

Hertz, Kristian Dahl

1992-01-01

Describes fire tests in which the increased risk of explosive spalling of concrete densified by silica fume was first discovered. Further results are discussed from tests to define appropriate limits of silica fume content and to develop a new concrete for slender column units. Observations are m...... are made about circumstances under which superplasticizing additives in concrete gave rise to the development of toxic gases....

Doses from the use of welding electrodes alloyed with thorium oxide

International Nuclear Information System (INIS)

Stranden, E.

1980-01-01

In tungsten inert gas welding the electrodes are alloyed with 1-2% thorium oxide to improve the welding properties. This has been found to form an aerosol with average particle size of about 0.1 μm. Previously reported values for activity in air near the head and thorax of a welder are used to calculate the radiation dose from inhalation under both conservative and realistic conditions. These values are compared with the annual limit of intake (ALI) specified by the ICRP in 1979 for thorium 232 and thorium 230, giving a conservative estimate of 48% of the ALI and a realistic estimate of 7%. It is concluded that there is no reason to forbid the use of thoriom alloyed welding electrodes at present, but that the matter should be followed up, and the use of these electrodes limited as far as possible. (JIW)

Investigation of durability of silica fume concretes in coastal structures within tidal zone

International Nuclear Information System (INIS)

Ganjian, E.; Sadeghi Pouya, H.

2003-01-01

In recent decade use of silica fume has been become greater in coastal concrete structures in the persona gulf, to increase durability of those establishments. In this research the durability of cement passers and concrete cubes with use of 7 and 10 percent of silica fume as a cement replacement have been investigated in three curing conditions (fresh water, coast of sea and simulation bonds) by measuring compressive strengths and capillary absorption. Silica fume specimens under wetting and drying condition showed more strength loss after 180 days compare to samples without silica fume or cured in the fresh water. In addition the greater silica fume amount in specimens cured within tidal zone and under wetting and drying simulation, the more water absorption by capillary. According to the results, good correspondence between simulated condition and real site exposure was obtained

Effects of Calcined clay minerals and Silica fume on the compressive strength of concrete

Directory of Open Access Journals (Sweden)

Abolfazl Soltani

2017-05-01

Full Text Available Pozzolanic materials are well known as potential replacements for cement manufacturing in order to increase compressive strength and improve durability of concrete in different environments and leading to save energy particularly reducing global warming effect. The present study reveals the effect of calcined clay minerals as natural pozzolanic material, separately and in combination with and without silica fume. To achieve this aim, 15 mixed designs with a constant water to cementitious ratio of  0.38 is made. In six mixed designs only metakaolin, zeolite or silica fume  and in eight other designs metakaolin and silica fume or zeolite and silica fume have been combined. Mixes containing metakaolin or zeolite with ratio of 10 or 20 percent and silica fume with 7 or 10 percent show significant increasing in compressive strength and improving durability, being valuable replacement for cement (in percentages. In particular, the best practice is attributed to the age of 28 days for compressive strength the replacement of the composition is 10% zeolite with 7% of silica fume and for electrical resistance the replacement of the composition is 10% zeolite with 7% of silica fume.

Effects of densified silica fume on microstructure and compressive strength of blended cement pastes

International Nuclear Information System (INIS)

Ji Yajun; Cahyadi, Jong Herman

2003-01-01

Some experimental investigations on the microstructure and compressive strength development of silica fume blended cement pastes are presented in this paper. The silica fume replacement varies from 0% to 20% by weight and the water/binder ratio (w/b) is 0.4. The pore structure by mercury intrusion porosimetry (MIP), the micromorphology by scanning electron microscopy (SEM) and the compressive strength at 3, 7, 14, 28, 56 and 90 days have been studied. The test results indicate that the improvements on both microstructure and mechanical properties of hardened cement pastes by silica fume replacement are not effective due to the agglomeration of silica fume particles. The unreacted silica fume remained in cement pastes, the threshold diameter was not reduced and the increase in compressive strength was insignificant up to 28 days. It is suggested that the proper measures should be taken to disperse silica fume agglomeration to make it more effective on improving the properties of materials

Influence of silica fume and fly ash on hydration, microstructure and strength of cement based mixtures

Energy Technology Data Exchange (ETDEWEB)

Weng, Kaimao

1992-10-01

The influence of fly ash and silica fume on the hydration, microstructure and strength of cement-based mixtures was investigated. A literature review of the hydration processes, compressive strength development, and microstructure of Portland cement is presented, followed by description of materials and specimens preparation and experimental methodology. It was found that silica fume retards cement hydration at low water/concrete ratios. It reduces calcium hydroxide significantly and increases the amount of hydrates at early ages. Fly ash retards hydration more significantly at high water/concrete ratios than at low ratios. The combination of silica fume and fly ash further retards hydration at one day. Silica fume dominates the reaction with calcium hydroxide. Silica fume significantly increases early strength of mortars and concrete, while fly ash reduces early strength. Silica fume can substantially increase strength of fly ash mortar and concrete after 7 days. Silica fume refines pores in the range 100-500 A, while fly ash mortars exhibit gradual pore refinement as hydration proceeds. Silica fume dominates the pore refinement if used with fly ash. 89 refs., 74 figs., 16 tabs.

Influence of polyolefin fibers on the engineering properties of cement-based composites containing silica fume

International Nuclear Information System (INIS)

Han, Ta-Yuan; Lin, Wei-Ting; Cheng, An; Huang, Ran; Huang, Chin-Cheng

2012-01-01

Highlights: ► Experimental study is focus on the engineering properties of cement-based composites. ► Different mixes containing fiber and silica fume proportions have been tested. ► The influence of different mixes on the engineering properties has been discussed. ► The properties are included strength, ductility, permeability and microstructure. -- Abstract: This study evaluated the mechanical properties of cement-based composites produced with added polyolefin fibers and silica fume. Material variables included the water-cementitious ratio, the dosage of silica fume, and the length and dosage of polyolefin fiber. Researchers conducted tests on compressive strength, splitting tensile strength, direct tensile strength, resistivity, rapid chloride penetration, and initial surface absorption, and performed microscopic observation. Test results indicate that the specimens containing silica fume have higher compressive strength than the control and specimen made with fibers. The specimens with polyolefin fiber and silica fume have considerably higher tensile strength and ductility than the control and specimens made with silica fume. The specimens containing silica fume and polyolefin fiber demonstrated better resistance to chloride penetration than composites with polyolefin fiber or silica fume. For a given volume fraction, short polyolefin fiber performs better than its long counterpart in improving the properties of concrete. Specimens containing silica fume demonstrated a significant increase in resistivity and decrease in the total charge passed and absorption. Scanning electron microscopy illustrates that the polyolefin fiber acts to arrest the propagation of internal cracks.

30 CFR 70.305 - Respiratory equipment; gas, dusts, fumes, or mists.

Science.gov (United States)

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Respiratory equipment; gas, dusts, fumes, or... LABOR COAL MINE SAFETY AND HEALTH MANDATORY HEALTH STANDARDS-UNDERGROUND COAL MINES Respiratory Equipment § 70.305 Respiratory equipment; gas, dusts, fumes, or mists. Respiratory equipment approved by...

Reaction products of densified silica fume agglomerates in concrete

International Nuclear Information System (INIS)

Diamond, Sidney; Sahu, Sadananda; Thaulow, Niels

2004-01-01

Most silica fume currently used in concrete is in the dry densified form and consists of agglomerates of sizes between 10 μm and several millimeters. Many of these agglomerates may break down only partially in normal concrete mixing. Examination of various mature silica-fume-bearing concretes using backscatter mode scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX) analysis shows that such agglomerates have reacted in situ and given rise to recognizable types of reaction products filling the space within the original outline of the agglomerate. One type is 'quiescent', and usually shows no evidence of volume instability. EDX spectra indicate that the product formed within such grains is C-S-H of very low Ca/Si ratio, with modest alkali contents. Other silica fume agglomerates may undergo a distinct alkali-silica-type reaction (ASR), with the reaction product found within the original outline of the agglomerate having significantly less calcium and usually much higher alkali contents than the quiescent type. Such reacted agglomerates show evidence of local expansion, shrinkage cracking (on drying), and other features common to ASR. Both types may be found within the same concrete, sometimes in close proximity. It further appears that exposure to seawater may convert previously formed reaction products of silica fume agglomerates to magnesium silicate hydrates

Potential inhalation exposure and containment efficiency when using hoods for handling nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Tsai, Candace Su-Jung, E-mail: tsai51@purdue.edu [Purdue University, School of Health Science (United States)

2013-09-15

Inhalation exposure to airborne nanoparticles (NPs) has been reported during manual activities using typical fume hoods. This research studied potential inhalation exposure associated with the manual handling of NPs using two new nanoparticle-handling enclosures and two biological safety cabinets, and discussed the ability to contain NPs in the hoods to reduce environmental release and exposure. Airborne concentrations of 5 nm to 20 {mu}m diameter particles were measured while handling nanoalumina particles in various ventilated enclosures. Tests were conducted using two handling conditions and concentrations were measured using real-time particle counters, and particles were collected on transmission electron microscope grids to determine particle morphology and elemental composition. Airflow patterns were characterized visually using a laser-light sheet and fog. The average number concentration increase at breathing zone outside the enclosure was less than 1,400 particle/cm{sup 3} for each particle size at all tested conditions and the estimated overall mass concentration was about 83 {mu}g/m{sup 3} which was less than the dosage of typical nanoparticle inhalation exposure studies. The typical front-to-back airflow was used in the studied hoods, which could potentially induce reverse turbulence in the wake region. However, containment of NPs using studied hoods was demonstrated with excellent performance. Smoke tests showed that worker's hand motion could potentially cause nanoparticle escape. The challenge of front-to-back airflow can be partially overcome by gentle motion, low face velocity, and front exhaust to reduce nanoparticle escape.

THE ROLE OF SHIELDING GAS ON MECHANICAL, METALLURGICAL AND CORROSION PROPERTIES OF CORTEN STEEL WELDED JOINTS OF RAILWAY COACHES USING GMAW

Directory of Open Access Journals (Sweden)

Byju John

2016-12-01

Full Text Available This analysis lays emphasis on finding a suitable combination of shielding gas for welding underframe members such as sole bar of Railway Coaches made of corten steel; for improved mechanical, metallurgical and corrosion properties of welds using copper coated solid MIG/MAG welding filler wire size 1.2 mm conforming to AWS/SFA 5.18 ER 70 S in Semi-automatic GMAW process. Solid filler wire is preferred by welders due to less fumes, practically no slag and easy manipulation of welding torch with smooth wire flow during corrosion repair attention, when compared to Flux cored wire. Three joints using Gas metal arc welding (GMAW with shielding gases viz., Pure CO2, (80% Ar – 20% CO2 and (90% Ar – 10% CO2 were made from test pieces cut from Sole bar material of Railway Coach. Study of Mechanical properties such as tensile strength, hardness and toughness revealed that welded joint made using shielding gas (80% Ar – 20% CO2 has better Mechanical properties compared to the other two shielding gases and comparable to that of Parent metal. Type of Shielding gas used has influence on the chemical composition and macro & micro structures. The Tafel extrapolation study of freshly ground samples in 3.5% NaCl solution revealed that the welded joint made using shielding gas (80% Ar – 20% CO2 has also better corrosion resistance which is comparable to the Parent metal as well as similar commercial steels.

Anatomical indications of fume resistance in certain woody plants

Energy Technology Data Exchange (ETDEWEB)

Ninova, D.

1970-01-01

An attempt is made to describe studies on seven species of fruit and forest trees close to or far from a Bulgarian factory emitting fumes containing S. The most resistant species (Quercus borealis, Gleditsia triacanthos, Morus alba) had the smallest stomata and the greatest number of stomata per unit leaf area. Changes observed in leaf anatomy as a result of exposure to the fumes were: decreased leaf aeration, elongated palisade cells, thicker cuticles, and more stomata.

Improvement of RVNRL film properties by adding fumed silica and hydroxy apatite

Directory of Open Access Journals (Sweden)

Adul Thiangchanya

2003-01-01

Full Text Available The effect of adding fumed silica and hydroxy apatite to Radiation Vulcanized Natural Rubber Latex (RVNRL for improving tear strength, aging properties, degradability and water-soluble protein content of rubber films has been investigated. The addition of fumed silica and hydroxy apatite in RVNRL improves tear strength and aging properties of rubber films, whereas tensile strength and degradability of rubber films were unchanged during storage at room temperature. The water-soluble protein content in rubber films was reduced by immobilization of the fumed silica and hydroxy apatite and enhanced by addition of ZnO. This may reduce allergy problems of natural rubber latex products caused by water-soluble protein. The MST of the RVNRL with fumed silica and hydroxy apatite indicated that the latex must be used within two months after mixing because of its stability.

Hepatotoxicity and genotoxicity of gasoline fumes in albino rats

Directory of Open Access Journals (Sweden)

Folarin O. Owagboriaye

2017-09-01

Full Text Available Toxic effects of gasoline fumes have been reported, but evidence of its hepatotoxicity and genotoxicity are rare. Therefore, this study assesses hepatotoxicity and genotoxicity of gasoline fumes on forty Albino rats randomly assigned to five experimental treatments (T with eight rats per treatment (T1, T2, T3, T4 and T5. T1(Control was housed in a section of experimental animal house free from gasoline fumes while T2, T3, T4 and T5 were exposed to gasoline fumes in exposure chambers for one, three, five and nine hours daily respectively for twelve weeks. Serum alanine aminotransferase (ALT, aspartate aminotransferase (AST, alkaline phosphatase (ALP and histopathological examination of the liver tissues were used as diagnostic markers to assess liver dysfunction. Genotoxicity test was conducted on the lung tissues using randomly amplified polymorphic DNA fingerprinting polymerase chain reaction (RAPD PCR technique. Significant increase (p < 0.05 in the level of ALT, AST and ALP for T2, T3, T4 and T5 compared to T1 were recorded. Photomicrograph examination of the liver sections of T1 showed hepatic tissue with normal liver cell architecture while that of T2, T3, T4 and T5 revealed degenerative changes in the ultrastructural integrity of the hepatic cells. Genotoxicity test revealed DNA bands at a reducing intensity from T1 to T5. Dendrogram showed DNA damage in the lungs of T3, T4 and T5 were closely similar and the genotoxic impact was more in T3. Frequent exposure to gasoline fumes was observed to induce hepatoxicity and genotoxicity, hence impairing the normal liver function and gene structure.

Formulation and characterization of date palm fibers mortar by addition of silica fume

Science.gov (United States)

Mokhtari, A.; Kriker, A.; Ouaggad, H.; Merad, N.

2018-05-01

This paper presents the results of experimental investigations of the formulated and characterization of date palm fibers mortar by addition of silica fume. The use of addition mineral is widely used in the production of cements through the world. The objective of this work is to bring our contribution to the recovery of local resources in the occurrence vegetable fibers of date palm to weak cost and from renewable source and integrate it in the filled of building. Date palm fiber are from Ouargla town in south of Algeria. Different mortar mixtures were prepared in which the cement was substitute by 10% of silica fume. The mechanical characteristics (compressive and flexural strength) of date palm fibers mortar by treatment of the matrix by the adding of silica fume were examined. The results obtained have shown that the mortar workability as well as the compressive and flexural strength decreases with increasing the silica fume replacement. The results showed that the use of silica fume enabled to evaluate the flexural strength. However, another treatment of fibers and matrix will be recommended for Improved the characteristics.

The mechanism of cesium immobilization in densified silica-fume blended cement pastes

International Nuclear Information System (INIS)

Bar-Nes, G.; Katz, A.; Peled, Y.; Zeiri, Y.

2008-01-01

The role of silica-fume agglomerates, found in densified silica-fume (DSF) pastes, in the immobilization mechanism of Cs ions was studied. Samples of cementitious pastes containing two different forms of silica fume - DSF and raw silica fume (RSF) - were prepared. Leaching experiments showed that both additives reduced the leachability of the metal ion, but the effect of the DSF paste was much stronger. Scanning Electron Microscopy, together with Differential Thermal Analysis, proved that no agglomerated particles were present in the RSF pastes and that the extent of pozzolanic reactivity was higher. We therefore believe that unreacted silica within the DSF agglomerates adsorbs Cs ions and consequently increases their immobilization. Furthermore, this work suggests that during the pozzolanic reaction, a hydrated rim develops around the agglomerate that acts as an additional diffusion barrier for the Cs ions, resulting in an increased efficiency of Cs immobilization

Stabilization of heavy metals in MSWI fly ash using silica fume

Energy Technology Data Exchange (ETDEWEB)

Li, Xinying; Chen, Quanyuan [School of Environment Science and Engineering, Donghua University, Shanghai 201620 (China); State Environmental Protection Engineering Center for Pollution Treatment and Control in Textile Industry, Donghua University, Shanghai 201620 (China); Zhou, Yasu [School of Environment Science and Engineering, Donghua University, Shanghai 201620 (China); Tyrer, Mark [Mineral Industry Research Organisation, Solihull B37 7HB (United Kingdom); Yu, Yang [School of Environment Science and Engineering, Donghua University, Shanghai 201620 (China)

2014-12-15

Highlights: • The stabilization of heavy metals in MSWI fly ash was investigated. • The addition of silica fume effectively reduced the leaching of Pb and Cd. • The relation of solid phase transformation and leaching behavior of heavy metals was discussed. - Abstract: The objective of this work was to investigate the feasibility and effectiveness of silica fume on stabilizing heavy metals in municipal solid waste incineration (MSWI) fly ash. In addition to compressive strength measurements, hydrated pastes were characterized by X-ray diffraction (XRD), thermal-analyses (DTA/TG), and MAS NMR ({sup 27}Al and {sup 29}Si) techniques. It was found that silica fume additions could effectively reduce the leaching of toxic heavy metals. At the addition of 20% silica fume, leaching concentrations for Cu, Pb and Zn of the hydrated paste cured for 7 days decreased from 0.32 mg/L to 0.05 mg/L, 40.99 mg/L to 4.40 mg/L, and 6.96 mg/L to 0.21 mg/L compared with the MSWI fly ash. After curing for 135 days, Cd and Pb in the leachates were not detected, while Cu and Zn concentrations decreased to 0.02 mg/L and 0.03 mg/L. The speciation of Pb and Cd by the modified version of the European Community Bureau of Reference (BCR) extractions showed that these metals converted into more stable state in hydrated pastes of MSWI fly ash in the presence of silica fume. Although exchangeable and weak-acid soluble fractions of Cu and Zn increased with hydration time, silica fume addition of 10% can satisfy the requirement of detoxification for heavy metals investigated in terms of the identification standard of hazardous waste of China.

42 CFR 84.1141 - Isoamyl acetate tightness test; dust, fume, and mist respirators designed for respiratory...

Science.gov (United States)

2010-10-01

... mist respirators designed for respiratory protection against fumes of various metals having an air... HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Dust, Fume, and Mist....1141 Isoamyl acetate tightness test; dust, fume, and mist respirators designed for respiratory...

Crosslinkable fumed silica-based nanocomposite electrolytes for rechargeable lithium batteries

Energy Technology Data Exchange (ETDEWEB)

Li, Yangxing; Yerian, Jeffrey A.; Khan, Saad A.; Fedkiw, Peter S. [Department of Chemical & amp; Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695-7905 (United States)

2006-10-27

Electrochemical and rheological properties are reported of composite polymer electrolytes (CPEs) consisting of dual-functionalized fumed silica with methacrylate and octyl groups+low-molecular weight poly(ethylene glycol) dimethyl ether (PEGdm)+lithium bis(trifluoromethanesulfonyl)imide (LiTFSI, lithium imide)+butyl methacrylate (BMA). The role of butyl methacrylate, which aids in formation of a crosslinked network by tethering adjacent fumed silica particles, on rheology and electrochemistry is examined together with the effects of fumed silica surface group, fumed silica weight percent, salt concentration, and solvent molecular weight. Chemical crosslinking of the fumed silica with 20% BMA shows a substantial increase in the elastic modulus of the system and a transition from a liquid-like/flocculated state to an elastic network. In contrast, no change in lithium transference number and only a modest decrease (factor of 2) on conductivity of the CPE are observed, indicating that a crosslinked silica network has minimal effect on the mechanism of ionic transport. These trends suggest that the chemical crosslinks occur on a microscopic scale, as opposed to a molecular scale, between adjacent silica particles and therefore do not impede the segmental mobility of the PEGdm. The relative proportion of the methacrylate and octyl groups on the silica surface displays a nominal effect on both rheology and conductivity following crosslinking although the pre-cure rheology is a function of the surface groups. Chemical crosslinked nanocomposite polymer electrolytes offer significant higher elastic modulus and yield stress than the physical nanocomposite counterpart with a small/negligible penalty of transport properties. The crosslinked CPEs exhibit good interfacial stability with lithium metal at open circuit, however, they perform poorly in cycling of lithium-lithium cells. (author)

Radon exhalation rates of concrete modified with fly ash and silica fumes

International Nuclear Information System (INIS)

Amit Kumar; Chauhan, R.P.; Mehta, Vimal; Kant, K.

2013-01-01

The radiological impact of the environmental gas radon to the health of general public is of concern since many decades. Cement used for the construction blended with fly ash and silica fumes is recommended by Government in order to avoid the soil and environmental pollution. But these addition step-up the Indoor radon level in the dwelling due to radioactivity contents. The exhalation of radon from concrete blended with silica fumes and fly ash depends upon addition level, porosity, moisture and radioactivity content. In order to optimize the level of substitution of silica fumes and fly ash, measurements of radon exhalation rates from the concrete blended with different proportions of fly ash and silica fumes was carried out using active scintillation radon monitor. The effect of porosity, moisture, back diffusion and radioactivity content of the concrete on exhalation rates is studied. The measured exhalation rates were extrapolated for indoor radon concentration and effective dose equivalent using ICRP, 1987 recommendations. (author)

deFUME: Dynamic exploration of functional metagenomic sequencing data

DEFF Research Database (Denmark)

van der Helm, Eric; Geertz-Hansen, Henrik Marcus; Genee, Hans Jasper

2015-01-01

is time consuming and constitutes a major bottleneck for experimental researchers in the field. Here we present the deFUME web server, an easy-to-use web-based interface for processing, annotation and visualization of functional metagenomics sequencing data, tailored to meet the requirements of non......-bioinformaticians. The web-server integrates multiple analysis steps into one single workflow: read assembly, open reading frame prediction, and annotation with BLAST, InterPro and GO classifiers. Analysis results are visualized in an online dynamic web-interface. The deFUME webserver provides a fast track from raw sequence...

Soldadura (Welding). Spanish Translations for Welding.

Science.gov (United States)

Hohhertz, Durwin

Thirty transparency masters with Spanish subtitles for key words are provided for a welding/general mechanical repair course. The transparency masters are on such topics as oxyacetylene welding; oxyacetylene welding equipment; welding safety; different types of welds; braze welding; cutting torches; cutting with a torch; protective equipment; arc…

Determining the Compressive, Flexural and Splitting Tensile Strength of Silica Fume Reinforced Lightweight Foamed Concrete

Directory of Open Access Journals (Sweden)

Mydin M.A.O.

2014-01-01

Full Text Available This study investigated the performance of the properties of foamed concrete in replacing volumes of cement of 10%, 15% and 20% by weight. A control unit of foamed concrete mixture made with ordinary Portland cement (OPC and 10%, 15% and 20% silica fume was prepared. Three mechanical property parameters were studied such as compressive strength, flexural strength and splitting tensile of foamed concrete with different percentages of silica fume. Silica fume is commonly used to increase the mechanical properties of concrete materials and it is also chosen due to certain economic reasons. The foamed concrete used in this study was cured at a relative humidity of 70% and a temperature of ±28°C. The improvement of mechanical properties was due to a significant densification in the microstructure of the cement paste matrix in the presence of silica fume hybrid supplementary binder as observed from micrographs obtained in the study. The overall results showed that there is a potential to utilize silica fume in foamed concrete, as there was a noticeable enhancement of thermal and mechanical properties with the addition of silica fume.

Exposure to Cooking Fumes and Acute Reversible Decrement in Lung Functional Capacity.

Science.gov (United States)

Neghab, Masoud; Delikhoon, Mahdieh; Norouzian Baghani, Abbas; Hassanzadeh, Jafar

2017-10-01

Being exposed to cooking fumes, kitchen workers are occupationally at risk of multiple respiratory hazards. No conclusive evidence exists as to whether occupational exposure to these fumes is associated with acute and chronic pulmonary effects and symptoms of respiratory diseases. To quantify the exposure levels and evaluate possible chronic and acute pulmonary effects associated with exposure to cooking fumes. In this cross-sectional study, 60 kitchen workers exposed to cooking fumes and 60 unexposed employees were investigated. The prevalence of respiratory symptoms among these groups was determined through completion of a standard questionnaire. Pulmonary function parameters were also measured before and after participants' work shift. Moreover, air samples were collected and analyzed to quantify their aldehyde, particle, and volatile organic contents. The mean airborne concentrations of formaldehyde, acetaldehyde, and acrolein was 0.45 (SD 0.41), 0.13 (0.1), and 1.56 (0.41) mg/m 3 , respectively. The mean atmospheric concentrations of PM 1 , PM 2.5 , PM 7 , PM 10 , and total volatile organic compounds (TVOCs) was 3.31 (2.6), 12.21 (5.9), 44.16 (16.6), 57 (21.55) μg/m 3 , and 1.31 (1.11) mg/m 3 , respectively. All respiratory symptoms were significantly (pcooking fumes is associated with a significant increase in the prevalence of respiratory symptoms as well as acute reversible decrease in lung functional capacity.

Levels and predictors of airborne and internal exposure to chromium and nickel among welders--results of the WELDOX study.

Science.gov (United States)

Weiss, Tobias; Pesch, Beate; Lotz, Anne; Gutwinski, Eleonore; Van Gelder, Rainer; Punkenburg, Ewald; Kendzia, Benjamin; Gawrych, Katarzyna; Lehnert, Martin; Heinze, Evelyn; Hartwig, Andrea; Käfferlein, Heiko U; Hahn, Jens-Uwe; Brüning, Thomas

2013-03-01

The objective of this analysis was to investigate levels and determinants of exposure to airborne and urinary chromium (Cr, CrU) and nickel (Ni, NiU) among 241 welders. Respirable and inhalable welding fume was collected during a shift, and the metal content was determined using inductively coupled plasma mass spectrometry. In post-shift urine, CrU and NiU were measured by means of graphite furnace atom absorption spectrometry, with resulting concentrations varying across a wide range. Due to a large fraction below the limits of quantitation we applied multiple imputations to the log-transformed exposure variables for the analysis of the data. Respirable Cr and Ni were about half of the concentrations of inhalable Cr and Ni, respectively. CrU and NiU were determined with medians of 1.2 μg/L (interquartile range exposure-modulating variables in form of multiplicative factors and revealed slightly better model fits for Cr (R(2) respirable Cr 48%, CrU 55%) than for Ni (R(2) respirable Ni 42%, NiU 38%). The air concentrations were mainly predicted by the metal content in electrodes or base material in addition to the welding technique. Respirable Cr and Ni were good predictors for CrU and NiU, respectively. Exposure was higher when welding was performed in confined spaces or with inefficient ventilation, and lower in urine when respirators were used. In conclusion, statistical modelling allowed the evaluation of determinants of internal and external exposure to Cr and Ni in welders. Welding parameters were stronger predictors than workplace conditions. Airborne exposure was lowest inside respirators with supply of purified air. Copyright © 2012 Elsevier GmbH. All rights reserved.

Objective measurement of inhaler inhalation flow profile using acoustic methods

Energy Technology Data Exchange (ETDEWEB)

Lacalle, H.; Taylor, T.E.; Marco, S.; Reilly, R.B.

2016-07-01

Patients with asthma and chronic obstructive pulmonary diseases (COPD) are mostly treated with inhalers that deliver medication directly to their airways. Drug delivery from dry powder inhalers (DPIs) is very much reliant on the inhalation manoeuvre, specifically the peak inspiratory flow rate (PIFR), inspiratory capacity (IC) and inhalation rise time (IRT) of the inhalation. It has been widely reported that patients may not follow correct inhalation technique while using their inhaler. In this study, a novel acoustic method is proposed to accurately estimate inhalation flow profile using only one inhalation recording for calibration. An Ellipta DPI was placed inside an airtight container with a spirometer connected in order to measure inhalation flow parameters. An acoustic recording device (Inhaler Compliance Assessment (INCA)) was also attached to the DPI. Inhalation audio and flow signals were recorded simultaneously. The data were collected from 20 healthy subjects while performing inhaler inhalations at a range of inspiratory flow rates. A power law regression model was computed to obtain the relationship between the acoustic envelope of the inhalation and flow profile of each recording. Each model was tested on the remaining audio signals to estimate flow profile. The average estimation error was found to be 10.5±0.3% for estimating flow profile from audio signals. Inhalation flow profile parameters (PIFR, IC and IRT) could then be measured from the estimated flow profile with high accuracy giving information on user inhalation technique. This method may assist in improving patient inhaler adherence and overall disease control. (Author)

Highly Efficient Fumed Silica Nanoparticles for Peptide Bond Formation: Converting Alanine to Alanine Anhydride.

Science.gov (United States)

Guo, Chengchen; Jordan, Jacob S; Yarger, Jeffery L; Holland, Gregory P

2017-05-24

In this work, thermal condensation of alanine adsorbed on fumed silica nanoparticles is investigated using thermal analysis and multiple spectroscopic techniques, including infrared (IR), Raman, and nuclear magnetic resonance (NMR) spectroscopies. Thermal analysis shows that adsorbed alanine can undergo thermal condensation, forming peptide bonds within a short time period and at a lower temperature (∼170 °C) on fumed silica nanoparticle surfaces than that in bulk (∼210 °C). Spectroscopic results further show that alanine is converted to alanine anhydride with a yield of 98.8% during thermal condensation. After comparing peptide formation on solution-derived colloidal silica nanoparticles, it is found that fumed silica nanoparticles show much better efficiency and selectivity than solution-derived colloidal silica nanoparticles for synthesizing alanine anhydride. Furthermore, Raman spectroscopy provides evidence that the high efficiency for fumed silica nanoparticles is likely related to their unique surface features: the intrinsic high population of strained ring structures present at the surface. This work indicates the great potential of fumed silica nanoparticles in synthesizing peptides with high efficiency and selectivity.

Pemanfaatan Mikrobakteri Terhadap Beton Mutu Tinggi dengan Tambahan Silica Fume

Directory of Open Access Journals (Sweden)

Azwar Annas

2016-04-01

Full Text Available Beton mutu tinggi adalah beton yang kuat tekan tinggi sekitar 50 MPa – 100 MPa. Untuk meningkatkan kuat tekan, material pozollan seperti silica fume dan flyash biasanya digunakan untuk mengganti material beton Dalam laporan ini, beton mutu tinggi dengan silica fume sebagai pengganti semen dipelajari. Kadar silica fume yang digunakan adalah 0%, 5%, 7,5% dan 10%. Selain itu pengaruh dari mikrobakteri juga dipelajari. Faktor water per binder yang dipakai adalah 25% dari berat binder, dan untuk membuat workabilitynya bagus maka digunakan superplasticizer. Kadar superplasticizer yang digunakan dicari lewat trial pengujian di laboratorium. Pengujian yang dilakukan pada umur 1, 3, 7, 14, 21, 28 adalah uji tekan pasta, mortar dan beton, selain itu pada benda uji beton umur 28 hari akan dilakukan uji split beton dan uji porositas. Dari hasil penelitian didapatkan kuat tekan beton tertinggi pada umur 28 hari (B7,5M adalah 69,71 MPa, sedangkan variasi silica fume yang paling optimum ada pada kadar 7,5%. Penambahan mikrobakteri tidak berpengaruh pada berat volume beton tetapi berpengaruh pada kuat tekan beton tersebut. Dengan penambahan mikrobakteri maka kuat tekan beton meningkat sebesar ± 30%. Sedangkan porositas total dan porositas tertutup yang terjadi pada beton semakin kecil, ini dibuktikan dengan hasil SEM terlihat bahwa bakteri mengisi area antara aggregat dan matrix beton.

Influence of polyacrylic ester and silica fume on the mechanical properties of mortar for repair application

Directory of Open Access Journals (Sweden)

Chaohua Jiang

2016-12-01

Full Text Available Experimental investigations on the influence of different amounts of polyacrylic ester and silica fumes on the mechanical properties of mortar such as the compressive strength, splitting tensile strength, bonding strength, and abrasion resistance are presented in this article. The results show that the compressive and splitting tensile strength of mortar can be improved with the addition of polyacrylic ester and silica fumes. Results obtained from both the direct tensile bond test and flexural bond test indicate that the addition of polyacrylic ester and silica fumes improves the bond strength significantly, and the enhancement is more obvious with polyacrylic ester paste as interfacial adhesives. Furthermore, mortar incorporation of polyacrylic ester and silica fumes shows superior abrasion resistance compared to the control mortar. Therefore, the correct combination of polyacrylic ester and silica fumes to produce mortars has been shown to have synergistic effects, which results in excellent properties including high bond strength and superior abrasion resistance. Mortars containing polyacrylic ester and silica fumes are ideal for repairing concrete especially for hydraulic concrete structure.

Experimental investigation on high performance RC column with manufactured sand and silica fume

Science.gov (United States)

Shanmuga Priya, T.

2017-11-01

In recent years, the use High Performance Concrete (HPC) has increased in construction industry. The ingredients of HPC depend on the availability and characteristics of suitable alternative materials. Those alternative materials are silica fume and manufactured sand, a by products from ferro silicon and quarry industries respectively. HPC made with silica fume as partial replacement of cement and manufactured sand as replacement of natural sand is considered as sustainable high performance concrete. In this present study the concrete was designed to get target strength of 60 MPa as per guide lines given by ACI 211- 4R (2008). The laboratory study was carried out experimentally to analyse the axial behavior of reinforced cement HPC column of size 100×100×1000mm and square in cross section. 10% of silica fume was preferred over ordinary portland cement. The natural sand was replaced by 0, 20, 40, 60, 80 and 100% with Manufactured Sand (M-Sand). In this investigation, totally 6 column specimens were cast for mixes M1 to M6 and were tested in 1000kN loading frame at 28 days. From this, Load-Mid height deflection curves were drawn and compared. Maximum ultimate load carrying capacity and the least deflection is obtained for the mix prepared by partial replacement of cement with 10% silica fume & natural sand by 100% M-Sand. The fine, amorphous and pozzalonic nature of silica fume and fine mineral particles in M- Sand increased the stiffness of HPC column. The test results revealed that HPC can be produced by using M-Sand with silica fume.

Occupational health concerns in the welding industry.

Science.gov (United States)

Korczynski, R E

2000-12-01

The Workplace Safety and Health Branch initiated a proactive study in the welding industry in Manitoba. Eight welding companies participated in this study. Health concerns raised by welders were welders' flash, sore/red/teary eyes, headaches, nosebleeds, and a black mucous discharge from their nasal membrane. Most welders expressed concern regarding excessive smoke levels in the workplace and inadequate ventilation. Types of welding identified were MIG mild steel, MIG stainless steel, and TIG aluminum. Monitoring involved an assessment of noise levels, fume composition, and carbon monoxide and ozone concentrations. Metal analyses were according to National Institute for Occupational Safety and Health (NIOSH) Method 7300. Noise dosimeters used were the Quest model 100 and Micro 14 & 15. Carbon monoxide was monitored using the Gastech Model 4700 and ozone using the AID Portable Ozone Meter Model 560. In Manitoba, a hearing conservation program is required when the equivalent sound exposure level (normalized Lex 8-hr) exceeds 80 dBA-weighted. The American Conference of Governmental Industrial Hygienists' threshold limit value-time weighted average (ACGIH TLV-TWA) for iron is 5.0 mg/m3, manganese is 0.2 mg/m3, carbon monoxide is 25 ppm, and ozone is 0.05 ppm (heavy work), 0.08 ppm (moderate work), and 0.1 ppm (light work). Welders' personal exposures to manganese ranged from 0.01-4.93 mg/m3 (N = 42; AM = 0.5; GM = 0.2; SD +/- 0.9; GSD +/- 3.2) and to iron ranged from 0.04-16.29 mg/m3 (N = 42; AM = 3.0; GM = 1.4; SD +/- 3.5; GSD +/- 2.5). Noise exposures ranged from 79-98 dBA (N = 44; AM = 88.9; GM = 88.8; SD +/- 4.2; GSD +/- 1.0). Carbon monoxide levels were less than 5.0 ppm (at source) and ozone levels varied from 0.4-0.6 ppm (at source). Ventilation upgrades in the workplace were required in most welding shops. Only 7 percent of the welders wore respiratory protection. A hearing conservation program and hearing protection were required at all monitored workplaces.

Thermogravimetric analyses and mineralogical study of polymer modified mortar with silica fume

Directory of Open Access Journals (Sweden)

Alessandra Etuko Feuzicana de Souza Almeida

2006-09-01

Full Text Available Mineral and organic additions are often used in mortars to improve their properties. Microstructural investigation concerning the effects of styrene acrylic polymer and silica fume on the mineralogical composition of high-early-strength portland cement pastes after 28 days of hydration are presented in this paper. Thermogravimetry and derivative thermogravimetry were used to study the interaction between polymers and cement, as well as the extent of pozzolanic reaction of the mortars with silica fume. Differential scanning calorimetry and X ray diffraction were used to investigate the cement hydration and the effect of the additions. The results showed that the addition of silica fume and polymer reduces the portlandite formation due to delaying of Portland cement hydration and pozzolanic reaction.

Determining the Compressive, Flexural and Splitting Tensile Strength of Silica Fume Reinforced Lightweight Foamed Concrete

OpenAIRE

Mydin M.A.O.; Sani N. Md.; Mohd Yusoff M.A.; Ganesan S.

2014-01-01

This study investigated the performance of the properties of foamed concrete in replacing volumes of cement of 10%, 15% and 20% by weight. A control unit of foamed concrete mixture made with ordinary Portland cement (OPC) and 10%, 15% and 20% silica fume was prepared. Three mechanical property parameters were studied such as compressive strength, flexural strength and splitting tensile of foamed concrete with different percentages of silica fume. Silica fume is commonly used to increase the m...

Addition of Silica Fume to Improve Strength of Cement Paste

Science.gov (United States)

Chen, Jiajian; Chen, Hongniao; Li, Gu

2018-03-01

This study measured the packing densities of 0 to 30% silica fume (SF) added cementitious materials and strength of the cementitious pastes with various water content. The results revealed that addition of silica fume up to a certain level has great effects on packing density and strength. In-depth analysis illustrated that a lower W/CM ratio would not always result in a higher cube strength, and the range between 0.05 and 0.07 µm would be the amount of water film thickness (WFT) for muximum strength.

INFLUENCE OF SUBSTITUTION OF ORDINARY PORTLAND CEMENT BY SILICA FUME ON THE HYDRATION OF SLAG-PORTLAND CEMENT PASTES

Directory of Open Access Journals (Sweden)

E.A. El-Alfi

2011-06-01

Full Text Available Effect of gradual substitution of ordinary Portland cement by a few percent of silica fume (0.0, 2.5, 5.0 and 7.5 wt.% on the hydration properties of slag-Portland cement pastes up to 12 months was investigated. The results show that the composite cement pastes containing silica fume give the higher physico-mechanical properties than that of the slag-Portland cement. Also, the XRD results reveal that the peak of Ca(OH2 shows higher intensity in the sample without silica fume and completely disappears in the sample containing 7.5 wt.% silica fume content. Also, the intensity peaks of C4AH13 sharply increase with silica fume content.

Radiological impact assessment of arc welding supplies rutile; Evaluacion del impacto radiologico de la soldadura por arco con consumibles de rutilo

Energy Technology Data Exchange (ETDEWEB)

Rozas Guinea, S.; Herranz Soler, M.; Perez Marin, C.; Idoeta Hermandorena, R.; Alegria gutierrez, N.; Nunez-Lagos Rogla, R.; Legarda Ibanez, F.

2013-07-01

Consumables for welding containing rutile, the coating of the electrode or the filling of tubular thread, are the most widely used and also the most radioactive since the rutile is a mineral containing traces of natural radionuclides, and is therefore considered Normal Occurring Radioactive Material (NORM). As these electrodes and wire are consumed, small particles, aerosols and gases are emitted to the atmosphere of work, and may be inhaled by the welder. Therefore, and also according to the current regulatory framework and work carried out previously by the author on the radiological impact of the process of manufacture and storage of coated rutile electrodes, the objectives are: 1Calcular the internal dose for inhalation during two types of welding, one with electrodes coated and the other with thread. 2 calculate the external dose due to the deposition of particles in the work environment, slag and the immersion of the soldering iron in the cloud of smoke. 3 to assess the radiological impact. (Author)

Characteristics of PAHs from deep-frying and frying cooking fumes.

Science.gov (United States)

Yao, Zhiliang; Li, Jing; Wu, Bobo; Hao, Xuewei; Yin, Yong; Jiang, Xi

2015-10-01

Cooking fumes are an important indoor source of polycyclic aromatic hydrocarbons (PAHs). Because indoor pollution has a more substantial impact on human health than outdoor pollution, PAHs from cooking fumes have drawn considerable attention. In this study, 16 PAHs emitted through deep-frying and frying methods using rapeseed, soybean, peanut, and olive oil were examined under a laboratory fume hood. Controlled experiments were conducted to collect gas- and particulate-phase PAHs emitted from the cooking oil fumes, and PAH concentrations were quantified via high-performance liquid chromatography (HPLC). The results show that deep-frying methods generate more PAHs and benzo[a]pyrene (B[a]P) (1.3 and 10.9 times, respectively) because they consume greater volumes of edible oil and involve higher oil temperatures relative to those of frying methods. In addition, the total B[a]Peq concentration of deep-frying is 2.2-fold larger than that of frying. Regarding the four types of edible oils studied, rapeseed oil produced more PAH emission than the other three oil varieties. For all of the cooking tests, three- and four-ringed PAHs were the main PAH components regardless of the food and oil used. Concerning the PAH partition between gas and particulate phase, the gaseous compounds accounted for 59-96 % of the total. Meanwhile, the particulate fraction was richer of high molecular weight PAHs (five-six rings). Deep-frying and frying were confirmed as important sources of PAH pollution in internal environments. The results of this study provide additional insights into the polluting features of PAHs produced via cooking activities in indoor environments.

Evaluation of consumer monitors to measure particulate matter.

Science.gov (United States)

Sousan, Sinan; Koehler, Kirsten; Hallett, Laura; Peters, Thomas M

2017-05-01

Recently, inexpensive (consumer aerosol monitors (CAMs) targeted for use in homes have become available. We evaluated the accuracy, bias, and precision of three CAMs (Foobot from Airoxlab, Speck from Carnegie Mellon University, and AirBeam from HabitatMap) for measuring mass concentrations in occupational settings. In a laboratory study, PM 2.5 measured with the CAMs and a medium-cost aerosol photometer (personal DataRAM 1500, Thermo Scientific) were compared to that from reference instruments for three aerosols (salt, welding fume, and Arizona road dust, ARD) at concentrations up to 8500 μg/m 3 . Three of each type of CAM were included to estimate precision. Compared to reference instruments, mass concentrations measured with the Foobot (r-value = 0.99) and medium-cost photometer (r-value = 0.99) show strong correlation, whereas those from the Speck (r-value range 0.88 - 0.99) and AirBeam (0.7 - 0.96) were less correlated. The Foobot bias was (-12%) for ARD and measurements were similar to the medium-cost instrument. Foobot bias was (< -46%) for salt and welding fume aerosols. Speck bias was at 18% salt for ARD and -86% for welding fume. AirBeam bias was (-36%) for salt and (-83%) for welding fume. All three photometers had a bias (< -82%) for welding fume. Precision was excellent for the Foobot (coefficient of variation range: 5% to 8%) and AirBeam (2% to 9%), but poorer for the Speck (8% to 25%). These findings suggest that the Foobot, with a linear response to different aerosol types and good precision, can provide reasonable estimates of PM 2.5 in the workplace after site-specific calibration to account for particle size and composition.

Prediction of Weld Residual Stress of Narrow Gap Welds

International Nuclear Information System (INIS)

Yang, Jun Seog; Huh, Nam Su

2010-01-01

The conventional welding technique such as shield metal arc welding has been mostly applied to the piping system of the nuclear power plants. It is well known that this welding technique causes the overheating and welding defects due to the large groove angle of weld. On the other hand, the narrow gap welding(NGW) technique has many merits, for instance, the reduction of welding time, the shrinkage of weld and the small deformation of the weld due to the small groove angle and welding bead width comparing with the conventional welds. These characteristics of NGW affect the deformation behavior and the distribution of welding residual stress of NGW, thus it is believed that the residual stress results obtained from conventional welding procedure may not be applied to structural integrity evaluation of NGW. In this paper, the welding residual stress of NGW was predicted using the nonlinear finite element analysis to simulate the thermal and mechanical effects of the NGW. The present results can be used as the important information to perform the flaw evaluation and to improve the weld procedure of NGW

Dynamic Moisture Sorption and Desorption in Fumed Silica-filled Silicone Foam

Energy Technology Data Exchange (ETDEWEB)

Trautschold, Olivia Carol [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2016-09-02

Characterizing dynamic moisture sorption and desorption in fumed silica-filled silicone foam is necessary for determining material compatibilities and life predictions, particularly in sealed environments that may be exposed to a range of environmental conditions. Thermogravimetric analysis (TGA) and near infrared spectroscopy (NIR) were performed on S5470 fumed silica-filled silicone foam to determine the weight percent of moisture at saturation. Additionally, TGA was used to determine the time, temperature, and relative humidity levels required for sorption and desorption of physisorbed moisture in S5470.

Inhaled Steroids

Science.gov (United States)

... considerations when your dosage changes. What about side effects and inhaled steroids? The most common side effects with inhaled steroids ... inhaled steroid has much less potential for side effects than steroid pills or syrups. There have been concerns regarding ...

Inhalant Abuse

Science.gov (United States)

... is when you pour the product into a bag, hold it over your mouth and nose, and inhale. How is inhalant abuse diagnosed? If you think your child is abusing inhalants, talk to them. Be honest and open. Tell them ...

The development and site investigation of fume diluter

Energy Technology Data Exchange (ETDEWEB)

Kim, Bok Youn; Kang, Chang Hee; Jo, Young Do; Lim, Sang Taek [Korea Institute of Geology Mining and Materials, Taejon (Korea, Republic of)

1996-12-01

It is third project year on `Application of mobile diesel equipment in underground mines` for providing appropriate measures to improve underground working environment contaminated by the diesel exhaust pollutants. For reducing the exhaust temperature bellow 70 deg. C to prevent production of the governing pollutant (NO{sub 2}), the fume diluter is verified the most effective device through the site investigation. Therefore, the fume diluter is strongly recommended instead of catalytic converter which is employed presently. The performances derived from the tests are as follows; 1) This device increased air flow to 6.7-8.4 times of the original exhaust, 2) Exhaust temperature can be reduced to 66 deg. C from 161 deg. C, 3) All the pollutants can be reduced to bellow than 30 % of exhaust concentration, 4) This device requires less cost and no maintenance. (author). 4 tabs., 4 figs.

Three-dimensional modelling of arc behaviour and gas shield quality in tandem gas-metal arc welding using anti-phase pulse synchronization

International Nuclear Information System (INIS)

Schnick, M; Lohse, M; Fuessel, U; Wilhelm, G; Murphy, A B

2011-01-01

The paper presents a transient three-dimensional model of an anti-phase-synchronized pulsed tandem gas-metal arc welding process, which is used to analyse arc interactions and their influence on the gas shield flow. The shielding gases considered are pure argon and a mixture of argon with 18% CO 2 . Comparison of the temperature fields predicted by the model with high-speed images indicates that the essential features of the interactions between the arcs are captured. The paper demonstrates strong arc deflection and kinking, especially during the low-current phase of the pulse, in agreement with experimental observations. These effects are more distinct for the argon mixture with 18% CO 2 . The second part of the paper demonstrates the effects of arc deflection and instabilities on the shielding gas flow and the occurrence of air contamination in the process region. The results allow an improved understanding of the causes of periodic instabilities and weld seam imperfections such as porosity, spatter, heat-tint oxidation and fume deposits.

Investigation on mechanical properties of welded material under different types of welding filler (shielded metal arc welding)

Science.gov (United States)

Tahir, Abdullah Mohd; Lair, Noor Ajian Mohd; Wei, Foo Jun

2018-05-01

The Shielded Metal Arc Welding (SMAW) is (or the Stick welding) defined as a welding process, which melts and joins metals with an arc between a welding filler (electrode rod) and the workpieces. The main objective was to study the mechanical properties of welded metal under different types of welding fillers and current for SMAW. This project utilized the Design of Experiment (DOE) by adopting the Full Factorial Design. The independent variables were the types of welding filler and welding current, whereas the other welding parameters were fixed at the optimum value. The levels for types of welding filler were by the models of welding filler (E6013, E7016 and E7018) used and the levels for welding current were 80A and 90A. The responses were the mechanical properties of welded material, which include tensile strength and hardness. The experiment was analyzed using the two way ANOVA. The results prove that there are significant effects of welding filler types and current levels on the tensile strength and hardness of the welded metal. At the same time, the ANOVA results and interaction plot indicate that there are significant interactions between the welding filler types and the welding current on both the hardness and tensile strength of the welded metals, which has never been reported before. This project found that when the amount of heat input with increase, the mechanical properties such as tensile strength and hardness decrease. The optimum tensile strength for welded metal is produced by the welding filler E7016 and the optimum of hardness of welded metal is produced by the welding filler E7018 at welding current of 80A.

Testing Silica Fume-Based Concrete Composites under Chemical and Microbiological Sulfate Attacks

Directory of Open Access Journals (Sweden)

Adriana Estokova

2016-04-01

Full Text Available Current design practices based on descriptive approaches to concrete specification may not be appropriate for the management of aggressive environments. In this study, the durability of cement-based materials with and without the addition of silica fume, subjected to conditions that leach calcium and silicon, were investigated. Chemical corrosion was simulated by employing various H2SO4 and MgSO4 solutions, and biological corrosion was simulated using Acidithiobacillus sp. bacterial inoculation, leading to disrupted and damaged surfaces; the samples’ mass changes were studied following both chemical and biological attacks. Different leaching trends were observed via X-ray fluorescence when comparing chemical with biological leaching. Lower leaching rates were found for concrete samples fortified with silica fume than those without silica fume. X-ray diffraction and scanning electron microscopy confirmed a massive sulfate precipitate formation on the concrete surface due to bacterial exposure.

Exposure to Cooking Fumes and Acute Reversible Decrement in Lung Functional Capacity

Directory of Open Access Journals (Sweden)

Masoud Neghab

2017-10-01

Full Text Available Background: Being exposed to cooking fumes, kitchen workers are occupationally at risk of multiple respiratory hazards. No conclusive evidence exists as to whether occupational exposure to these fumes is associated with acute and chronic pulmonary effects and symptoms of respiratory diseases. Objective: To quantify the exposure levels and evaluate possible chronic and acute pulmonary effects associated with exposure to cooking fumes. Methods: In this cross-sectional study, 60 kitchen workers exposed to cooking fumes and 60 unexposed employees were investigated. The prevalence of respiratory symptoms among these groups was determined through completion of a standard questionnaire. Pulmonary function parameters were also measured before and after participants' work shift. Moreover, air samples were collected and analyzed to quantify their aldehyde, particle, and volatile organic contents. Results: The mean airborne concentrations of formaldehyde, acetaldehyde, and acrolein was 0.45 (SD 0.41, 0.13 (0.1, and 1.56 (0.41 mg/m3, respectively. The mean atmospheric concentrations of PM1, PM2.5, PM7, PM10, and total volatile organic compounds (TVOCs was 3.31 (2.6, 12.21 (5.9, 44.16 (16.6, 57 (21.55 μg/m3, and 1.31 (1.11 mg/m3, respectively. All respiratory symptoms were significantly (p<0.05 more prevalent in exposed group. No significant difference was noted between the pre-shift mean of spirometry parameters of exposed and unexposed group. However, exposed workers showed cross-shift decrease in most spirometry parameters, significantly lower than the pre-shift values and those of the comparison group. Conclusion: Exposure to cooking fumes is associated with a significant increase in the prevalence of respiratory symptoms as well as acute reversible decrease in lung functional capacity.

Bronchiolitis from nitrous fumes

Energy Technology Data Exchange (ETDEWEB)

Darke, C S; Warrack, A J.N.

1958-01-01

Gases of low solubility (e.g., NO/sub 2/) may not irritate upper respiratory tract but may act insidiously on lower tract producing edema and bronchiolitis. Cases of bronchiolitis (1 resulting in death) from exposure to brown nitrous fumes are reported. There were no or slight symptoms at first but severe ones after about 1 wk. Pathology appears as acute pulmonary edema with damage and desquamation of alveolar epithelium particularly and that of respiratory bronchioles somewhat. Patchy atelectasis, bronchopneumonia and disruption of fibers in cell walls may also occur. Severe cases have obliteration of lumen (bronchiolitis obliterans) with extreme distress and death.

Performance of Portland cement mixes containing silica fume and mixed with lime-water

Directory of Open Access Journals (Sweden)

Metwally A.A. Abd Elaty

2014-12-01

Test results show that using lime-water in mixing enhances consistency degree compared to the corresponding control mixes. Furthermore, it delays both initial and final setting times compared with traditional water due to the common ion effect principles. Moreover, combined use of lime-water and silica fume enhances the pozzolanic reaction that was identified by the strength development at both early and later ages. The existence of CH crystals for higher percentages of silica fume (up to 30% for further reaction at later ages was observed by XRD results. Moreover, combined use of silica fume and lime-water ensures a high alkaline media around steel bars from the moment of ingredients mixing as long as later ages despite of pozzolanic reaction that was identified from results of chloride attack.

Persistence of Change: Fume Hood Campaign Lessons

Science.gov (United States)

Feder, Elah; Robinson, Jennifer; Wakefield, Sarah

2012-01-01

Purpose: Sustainability initiatives typically operate for a limited time period, but it is often unclear whether they have lasting effects. The purpose of this paper is to examine a laboratory fume hood campaign, in order to identify factors that might contribute or detract from long-term change persistence. Design/methodology/approach: The…

Effect of silica fume on compressive strength of oil-polluted concrete in different marine environments

Science.gov (United States)

Shahrabadi, Hamid; Sayareh, Sina; Sarkardeh, Hamed

2017-12-01

In the present research, effect of silica fume as an additive and oil polluted sands as aggregates on compressive strength of concrete were investigated experimentally. The amount of oil in the designed mixtures was assumed to be constant and equal to 2% of the sand weight. Silica fume accounting for 10%, 15% and 20% of the weight is added to the designed mixture. After preparation and curing, concrete specimens were placed into the three different conditions: fresh, brackish and saltwater environments (submerged in fresh water, alternation of exposed in air & submerged in sea water and submerged in sea water). The result of compressive strength tests shows that the compressive strength of the specimens consisting of silica fume increases significantly in comparison with the control specimens in all three environments. The compressive strength of the concrete with 15% silica fume content was about 30% to 50% higher than that of control specimens in all tested environments under the condition of using polluted aggregates in the designed mixture.

Effect of temperature on physical and mechanical properties of concrete containing silica fume

International Nuclear Information System (INIS)

Saad, M.; Hanna, G.B.; Abo-El-Enein, S.A.; Kotkata, M.F.

1996-01-01

Heat-resistant materials are usually used for structural purposes. The need for such building materials is particularly important in the chemical and metallurgical industries and for the thermal shieldings of nuclear power plants. Thus the effect of high temperatures on physical and mechanical properties of concrete was investigated. In this study ordinary Portland cement has been partially replaced by ratios of silica fume. The heat treatment temperature varied from 100 to 600 C by increments of 100 C for three hours without any load. Concrete specimens were treated at each temperature level. The specimens were heated under the same condition for each temperature level. Comparison between physical and mechanical properties during heat treatment were investigated. All specimens were moist-cured for 28 days after casting. Tests were carried out on specimens cooled slowly to room temperature after heating. Results of this investigation indicated that the replacement of ordinary Portland cement by 10% silica fume by weight improved the compressive strength by about 64.6%, but replacement of ordinary Portland cement by silica fume by ratios 20 and 30% improved the compressive strength by only 28% at 600 C. This could be attributed to the additional tobermorite gel (CSH phase) which formed due to the reaction of silica fume with Ca(OH) 2

Weld Nugget Temperature Control in Thermal Stir Welding

Science.gov (United States)

Ding, R. Jeffrey (Inventor)

2014-01-01

A control system for a thermal stir welding system is provided. The control system includes a sensor and a controller. The sensor is coupled to the welding system's containment plate assembly and generates signals indicative of temperature of a region adjacent and parallel to the welding system's stir rod. The controller is coupled to the sensor and generates at least one control signal using the sensor signals indicative of temperature. The controller is also coupled to the welding system such that at least one of rotational speed of the stir rod, heat supplied by the welding system's induction heater, and feed speed of the welding system's weld material feeder are controlled based on the control signal(s).

Manganese Fractionation Using a Sequential Extraction Method to Evaluate Welders' Shielded Metal Arc Welding Exposures During Construction Projects in Oil Refineries.

Science.gov (United States)

Hanley, Kevin W; Andrews, Ronnee; Bertke, Steven; Ashley, Kevin

2015-01-01

The National Institute for Occupational Safety and Health has conducted an occupational exposure assessment study of manganese (Mn) in welding fume of construction workers rebuilding tanks, piping, and process equipment at two oil refineries. The objective of this study was to evaluate exposures to different Mn fractions using a sequential extraction procedure. Seventy-two worker-days were monitored for either total or respirable Mn during stick welding and associated activities both within and outside of confined spaces. The samples were analyzed using an experimental method to separate different Mn fractions by valence states based on selective chemical solubility. The full-shift total particulate Mn time-weighted average (TWA) breathing zone concentrations ranged from 0.013-29 for soluble Mn in a mild ammonium acetate solution; from 0.26-250 for Mn(0,2+) in acetic acid; from non-detectable (ND) - 350 for Mn(3+,4+) in hydroxylamine-hydrochloride; and from ND - 39 micrograms per cubic meter (μg/m(3)) for insoluble Mn fractions in hydrochloric and nitric acid. The summation of all Mn fractions in total particulate TWA ranged from 0.52-470 μg/m(3). The range of respirable particulate Mn TWA concentrations were from 0.20-28 for soluble Mn; from 1.4-270 for Mn(0,2+); from 0.49-150 for Mn(3+,4+); from ND - 100 for insoluble Mn; and from 2.0-490 μg/m(3) for Mn (sum of fractions). For all jobs combined, total particulate TWA GM concentrations of the Mn(sum) were 99 (GSD = 3.35) and 8.7 (GSD = 3.54) μg/m(3) for workers inside and outside of confined spaces; respirable Mn also showed much higher levels for welders within confined spaces. Regardless of particle size and confined space work status, Mn(0,2+) fraction was the most abundant followed by Mn(3+,4+) fraction, typically >50% and ∼30-40% of Mn(sum), respectively. Eighteen welders' exposures exceeded the ACGIH Threshold Limit Values for total Mn (100 μg/m(3)) and 25 exceeded the recently adopted respirable

Transition welds in welding of two-ply steels

International Nuclear Information System (INIS)

Fartushnyj, V.G.; Evsyukov, Yu.G.

1977-01-01

Studied were physico-mechanical properties of welds made by various welding wires of chromium-nickel and nickel-chromium steels in submerged arc welding of double-layer steels with main layer of the VSt.3sp. carbon steel. It is shown that service-reliable structures welded of two-layer steels are obtained by providing the content from 11 to 20 % Ni in the automatically welded transition layer

Effect of silica fume on reaction products of uranium (VI) with portland cement

International Nuclear Information System (INIS)

Tan Hongbin; Shaanxi Univ. of Technology, Hanzhong; Li Yuxiang

2005-01-01

Simulation of radioactive waste of U(VI) by uranyl nitrate and the effects of different additive quantities (12%, 20%, 30%, 35%, 40%) of silica fume on the products of U(VI) with Portland cement were studied at a hydrothermal condition of 180 degree C for a duration of one week. The X-ray powder diffraction examination results showed that the calcium uranate would be transformed into uranophane when the cement contained 30% silica fume. (authors)

Weld controller for automated nuclear service welding

International Nuclear Information System (INIS)

Barfield, K.L.; Strubhar, P.M.; Green, D.I.

1995-01-01

B and W Nuclear Technologies (BWNT) uses many different types of weld heads for automated welding in the commercial nuclear service industry. Some weld heads are purchased as standard items, while others are custom designed and fabricated by BWNT requiring synchronized multiaxis motion control. BWNT recently completed a development program to build a common weld controller that interfaces to all types of weld heads used by BWNT. Their goal was to construct a system that had the flexibility to add different modules to increase the capability of the controller as different application needs become necessary. The benefits from having a common controller are listed. This presentation explains the weld controller system and the types of applications to which it has been applied

Work-principle model for predicting toxic fumes of nonideal explosives

Energy Technology Data Exchange (ETDEWEB)

Wieland, Michael S. [National Institute of Occupational Safety and Health, Pittsburgh Research Center, P.O. Box 18070, Pittsburgh, PA 15236-0070 (United States)

2004-08-01

The work-principle from thermodynamics was used to formulate a model for predicting toxic fumes from mining explosives in underground chamber tests, where rapid turbulent combustion within the surrounding air noticeably changes the resulting concentrations. Two model constants were required to help characterize the reaction zone undergoing rapid chemical transformations in conjunction with heat transfer and work output: a stoichiometry mixing fraction and a reaction-quenching temperature. Rudimentary theory with an unsteady uniform concentration gradient was taken to characterize the combustion zone, yielding 75% for the mixing fraction. Four quenching temperature trends were resolved and compared to test results of ammonium nitrate compositions with different fuel-oil percentages (ANFO). The quenching temperature 2345 K was the optimum choice for fitting the two major components of fume toxicity: carbon monoxide (CO) and total nitrogen oxides (NO{sub X}). The resulting two-constant model was used to generate comparisons for test results of ANFO compositions with additives. Though respectable fits were usually found, charge formulations which reacted weakly could not be resolved numerically. The work-principle model yields toxic concentrations for a range of charge formulations, making it a useful tool for investigating the potential hazard of released fumes and reducing the risk of unwanted incidents. (Abstract Copyright [2004], Wiley Periodicals, Inc.)

Use of servo controlled weld head for end closure welding

Energy Technology Data Exchange (ETDEWEB)

Pathak, S.K.; Setty, D.S.; Rameswara Rao, A.; Hemantha Rao, G.V.S.; Jayaraj, R.N. [Nuclear Fuel Complex, Dept. of Atomic Energy, Hyderabad (India)

2010-07-01

In the PHWR fuel fabrication line resistance welding processes are used for joining various zirconium based alloy components to fuel tube of similar material. The quality requirement of these welding processes is very stringent and has to meet all the product requirements. At present these welding processes are being carried out by using standard resistance welding machines. In the resistance welding process in addition to current and time, force is one of the critical and important parameter, which influences the weld quality. At present advanced feed back type fast response medium frequency weld controllers are being used. This has upslope/down slope, constant and repetitive weld pattern selection features makes this critical welding process more reliable. Compared to weld controllers, squeeze force application devices are limited and normally standard high response pneumatic cylinders are used in the welding process. With this type of devices the force is constant during welding process and cannot be varied during welding process as per the material deformation characteristics. Similarly due to non-availability of feed back systems in the squeeze force application systems restricts the accuracy and quality of the welding process. In the present paper the influence of squeeze force pattern on the weld quality using advanced feed back type servo based force control system was studied. Different squeeze forces were used during pre and post weld heat periods along with constant force and compared with the weld quality. (author)

Welding hazards

International Nuclear Information System (INIS)

Khan, M.A.

1992-01-01

Welding technology is advancing rapidly in the developed countries and has converted into a science. Welding involving the use of electricity include resistance welding. Welding shops are opened in residential area, which was causing safety hazards, particularly the teenagers and children who eagerly see the welding arc with their naked eyes. There are radiation hazards from ultra violet rays which irritate the skin, eye irritation. Welding arc light of such intensity could damage the eyes. (Orig./A.B.)

Pulmonary hemorrhage and edema due to inhalation of resins containing tri-mellitic anhydride.

Science.gov (United States)

Herbert, F A; Orford, R

1979-11-01

Seven young men developed acute pulmonary hemorrhage and edema from the inhalation of powder or fumes of a bisphenol epoxy resin containing tri-mellitic anhydride (TMA) while working in a steel pipe-coating plant. The illness was characterized by cough, hemoptysis, dyspnea, fever, weakness and nausea or vomiting. Chest roentgenograms showed either a bilateral or unilateral pulmonary infiltrate. All patients had a normochromic type of anemia. Pulmonary function studies demonstrated a restrictive defect, hypoxemia, and increased A-a DO2 gradients. Light and electron microscopic studies of lung tissue revealed extensive bleeding into alveoli but no basement membrane deposits were seen and no antiglomerular basement membrane antibodies were detected. The patients improved quickly without treatment. Follow-up studies of six patients three weeks to one year after their illness revealed apparent recovery. A detailed medical survey carried out on all 29 workers currently employed in the plant revealed five additional men had experienced severe recurrent pulmonary problems.

Estimation of inhalation flow profile using audio-based methods to assess inhaler medication adherence

Science.gov (United States)

Lacalle Muls, Helena; Costello, Richard W.; Reilly, Richard B.

2018-01-01

Asthma and chronic obstructive pulmonary disease (COPD) patients are required to inhale forcefully and deeply to receive medication when using a dry powder inhaler (DPI). There is a clinical need to objectively monitor the inhalation flow profile of DPIs in order to remotely monitor patient inhalation technique. Audio-based methods have been previously employed to accurately estimate flow parameters such as the peak inspiratory flow rate of inhalations, however, these methods required multiple calibration inhalation audio recordings. In this study, an audio-based method is presented that accurately estimates inhalation flow profile using only one calibration inhalation audio recording. Twenty healthy participants were asked to perform 15 inhalations through a placebo Ellipta™ DPI at a range of inspiratory flow rates. Inhalation flow signals were recorded using a pneumotachograph spirometer while inhalation audio signals were recorded simultaneously using the Inhaler Compliance Assessment device attached to the inhaler. The acoustic (amplitude) envelope was estimated from each inhalation audio signal. Using only one recording, linear and power law regression models were employed to determine which model best described the relationship between the inhalation acoustic envelope and flow signal. Each model was then employed to estimate the flow signals of the remaining 14 inhalation audio recordings. This process repeated until each of the 15 recordings were employed to calibrate single models while testing on the remaining 14 recordings. It was observed that power law models generated the highest average flow estimation accuracy across all participants (90.89±0.9% for power law models and 76.63±2.38% for linear models). The method also generated sufficient accuracy in estimating inhalation parameters such as peak inspiratory flow rate and inspiratory capacity within the presence of noise. Estimating inhaler inhalation flow profiles using audio based methods may be

PEMANFAATAN LIMBAH SERBUK MARMER PADA BETON SEBAGAI BAHAN PENGGANTI SEBAGIAN SEMEN DENGAN VARIASI PENGGUNAAN SILICA FUME

OpenAIRE

Agil Fitri Handayani; Agoes Soehardjono M.D.; Achfas Zacoeb

2015-01-01

The Utilization of Marble Powder Waste in Concrete Ma­­­­­­­­terials as a Partial Material Substitution of Cement  with the Variation Use of Silica Fume. The purpose of this study was to determine the effect of marble powder and silica fume on the mechanical pro­per­ties of concrete. This study used an experimental design using 16 group of testing materials with variety types of mixtures between marble powder and silica fume 0.00; 5.00; 10.00; and 15.00%. The wa­ter-cement ratio was 0.50 and ...

Enhancing the performance of green solid-state electric double-layer capacitor incorporated with fumed silica nanoparticles

Science.gov (United States)

Chong, Mee Yoke; Numan, Arshid; Liew, Chiam-Wen; Ng, H. M.; Ramesh, K.; Ramesh, S.

2018-06-01

Solid polymer electrolyte (SPE) based on fumed silica nanoparticles as nanofillers, hydroxylethyl cellulose (HEC) as host polymer, magnesium trifluoromethanesulfonate salt and 1-ethyl-3-methylimidazolium trifluoromethanesulfonate ionic liquid is prepared by solution casting technique. The ionic conductivity, interactions of adsorbed ions on the host polymer, structural crystallinity and thermal stability are evaluated by electrochemical impedance spectroscopy (EIS), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and thermogravimetric analysis (TGA), respectively. Ionic conductivity studies at room temperature reveals that the SPE with 2 wt. % of fumed silica nanoparticles gives the highest conductivity compared to its counterpart. The XRD and FTIR studies confirm the dissolution of salt, ionic liquid and successful incorporation of fumed silica nanoparticles with host polymer. In order to examine the performance of SPEs, electric double-layer capacitor (EDLC) are fabricated by using activated carbon electrodes. EDLC studies demonstrate that SPE incorporated with 2 wt. % fumed silica nanoparticles gives high specific capacitance (25.0 F/g) at a scan rate of 5 mV/s compared to SPE without fumed silica. Additionally, it is able to withstand 71.3% of capacitance from its initial capacitance value over 1600 cycles at a current density of 0.4 A/g.

Advanced Welding Concepts

Science.gov (United States)

Ding, Robert J.

2010-01-01

Four advanced welding techniques and their use in NASA are briefly reviewed in this poster presentation. The welding techniques reviewed are: Solid State Welding, Friction Stir Welding (FSW), Thermal Stir Welding (TSW) and Ultrasonic Stir Welding.

Resistance seam welding

International Nuclear Information System (INIS)

Schueler, A.W.

1977-01-01

The advantages and disadvantages of the resistance seam welding process are presented. Types of seam welds, types of seam welding machines, seam welding power supplies, resistance seam welding parameters and seam welding characteristics of various metals

Welding method, and welding device for use therein, and method of analysis for evaluating welds

NARCIS (Netherlands)

Aendenroomer, A.J.; Den Ouden, G.; Xiao, Y.H.; Brabander, W.A.J.

1995-01-01

Described is a method of automatically welding pipes, comprising welding with a pulsation welding current and monitoring, by means of a sensor, the variations occurring in the arc voltage caused by weld pool oscillations. The occurrence of voltage variations with only frequency components below 100

Comparison of Welding Residual Stresses of Hybrid Laser-Arc Welding and Submerged Arc Welding in Offshore Steel Structures

DEFF Research Database (Denmark)

Andreassen, Michael Joachim; Yu, Zhenzhen; Liu, Stephen

2016-01-01

In the offshore industry, welding-induced distortion and tensile residual stresses have become a major concern in relation to the structural integrity of a welded structure. Particularly, the continuous increase in size of welded plates and joints needs special attention concerning welding induced...... residual stresses. These stresses have a negative impact on the integrity of the welded joint as they promote distortion, reduce fatigue life, and contribute to corrosion cracking and premature failure in the weld components. This paper deals with the influence and impact of welding method on the welding...... induced residual stresses. It is also investigated whether the assumption of residual stresses up to yield strength magnitude are present in welded structures as stated in the design guidelines. The fatigue strength for welded joints is based on this assumption. The two welding methods investigated...

Welding technology transfer task/laser based weld joint tracking system for compressor girth welds

Science.gov (United States)

Looney, Alan

1991-01-01

Sensors to control and monitor welding operations are currently being developed at Marshall Space Flight Center. The laser based weld bead profiler/torch rotation sensor was modified to provide a weld joint tracking system for compressor girth welds. The tracking system features a precision laser based vision sensor, automated two-axis machine motion, and an industrial PC controller. The system benefits are elimination of weld repairs caused by joint tracking errors which reduces manufacturing costs and increases production output, simplification of tooling, and free costly manufacturing floor space.

After-blast fumes from ANFO mixtures - the effect of prill type and mixing techniques

Energy Technology Data Exchange (ETDEWEB)

Farnfield, R.; Wetherelt, A.

2003-06-01

Over the last couple of years the Technical Services Department of exchem explosives has received a number of enquiries regarding the nature of after-blast fumes. These enquiries have been driven by two concerns: site-related health and safety and public comment from people living close to blasting operations. The paper examines how these choices can impact the quality and quantity of after-blast fume. 3 refs., 9 figs., 3 tabs.

Friction Stir Welding

Science.gov (United States)

Nunes, Arthur C., Jr.

2008-01-01

Friction stir welding (FSW) is a solid state welding process invented in 1991 at The Welding Institute in the United Kingdom. A weld is made in the FSW process by translating a rotating pin along a weld seam so as to stir the sides of the seam together. FSW avoids deleterious effects inherent in melting and promises to be an important welding process for any industries where welds of optimal quality are demanded. This article provides an introduction to the FSW process. The chief concern is the physical effect of the tool on the weld metal: how weld seam bonding takes place, what kind of weld structure is generated, potential problems, possible defects for example, and implications for process parameters and tool design. Weld properties are determined by structure, and the structure of friction stir welds is determined by the weld metal flow field in the vicinity of the weld tool. Metal flow in the vicinity of the weld tool is explained through a simple kinematic flow model that decomposes the flow field into three basic component flows: a uniform translation, a rotating solid cylinder, and a ring vortex encircling the tool. The flow components, superposed to construct the flow model, can be related to particular aspects of weld process parameters and tool design; they provide a bridge to an understanding of a complex-at-first-glance weld structure. Torques and forces are also discussed. Some simple mathematical models of structural aspects, torques, and forces are included.

Effect of Generator (Exhaust) Fumes on the Growth and ...

African Journals Online (AJOL)

PROF HORSFALL

as the distance of the plants from the source of pollution increased, only the 3 m treatment led to significant ... plants were adversely affected by the fume emission especially at the distance of 3 m away from the ..... Principles of Biochemical.

Numerical analysis of weld pool oscillation in laser welding

Energy Technology Data Exchange (ETDEWEB)

Cho, Jung Ho [Chungbuk National University, Cheongju (Korea, Republic of); Farson, Dave F [The Ohio State University, Columbus (United States); Hollis, Kendall; Milewski, John O. [Los Alamos National Laboratory, Los Alamos (United States)

2015-04-15

Volume of fluid (VOF) numerical simulation was used to investigate melt flow and volumetric oscillation of conduction-mode pulsed laser weld pools. The result is compared to high speed video stream of titanium laser spot welding experiment. The total simulation time is 10ms with the first 5 ms being heating and melting under constant laser irradiation and the remaining 5 ms corresponding to resolidification of the weld pool. During the melting process, the liquid pool did not exhibit periodic oscillation but was continually depressed by the evaporation recoil pressure. After the laser pulse, the weld pool was excited into volumetric oscillation by the release of pressure on its surface and oscillation of the weld pool surface was analyzed. The simulation model suggested adjusting thermal diffusivity to match cooling rate and puddle diameter during solidification which is distinguishable from previous weld pool simulation. The frequency continuously increased from several thousand cycles per second to tens of thousands of cycles per second as the weld pool solidified and its diameter decreased. The result is the first trial of investigation of small weld pool oscillation in laser welding although there have been several reports about arc welding.

Alternate Welding Processes for In-Service Welding

Science.gov (United States)

2009-04-24

Conducting weld repairs and attaching hot tap tees onto pressurized pipes has the advantage of avoiding loss of service and revenue. However, the risks involved with in-service welding need to be managed by ensuring that welding is performed in a rep...

Hybrid laser-TIG welding, laser beam welding and gas tungsten arc welding of AZ31B magnesium alloy

International Nuclear Information System (INIS)

Liu Liming; Wang Jifeng; Song Gang

2004-01-01

Welding of AZ31B magnesium alloy was carried out using hybrid laser-TIG (LATIG) welding, laser beam welding (LBW) and gas tungsten arc (TIG) welding. The weldability and microstructure of magnesium AZ31B alloy welded using LATIG, LBW and TIG were investigated by OM and EMPA. The experimental results showed that the welding speed of LATIG was higher than that of TIG, which was caught up with LBW. Besides, the penetration of LATIG doubles that of TIG, and was four times that of LBW. In addition, arc stability was improved in hybrid of laser-TIG welding compared with using the TIG welding alone, especially at high welding speed and under low TIG current. It was found that the heat affect zone of joint was only observed in TIG welding, and the size of grains in it was evidently coarse. In fusion zone, the equiaxed grains exist, whose size was the smallest welded by LBW, and was the largest by TIG welding. It was also found that Mg concentration of the fusion zone was lower than that of the base one by EPMA in three welding processes

Inhalation Therapy in Horses.

Science.gov (United States)

Cha, Mandy L; Costa, Lais R R

2017-04-01

This article discusses the benefits and limitations of inhalation therapy in horses. Inhalation drug therapy delivers the drug directly to the airways, thereby achieving maximal drug concentrations at the target site. Inhalation therapy has the additional advantage of decreasing systemic side effects. Inhalation therapy in horses is delivered by the use of nebulizers or pressured metered dose inhalers. It also requires the use of a muzzle or nasal mask in horses. Drugs most commonly delivered through inhalation drug therapy in horses include bronchodilators, antiinflammatories, and antimicrobials. Copyright © 2016 Elsevier Inc. All rights reserved.

Closing the weld gap with laser/mig hybrid welding process

DEFF Research Database (Denmark)

Bagger, Claus; Olsen, Flemming Ove; Wiwe, Bjarne David

2003-01-01

In this article, laboratory tests are demonstrated that systematically accesses the critical gap distance when welding CMn 2.13 mm steel with a 2.6 kW CO2 laser, combined with a MIG energy source. In the work, the welding speed is varied at gap distances from 0 to 0.8 mm such that the limits...... for obtaining sound welds are identified. The welds are quality assessed according to ISO 13.919-1 and EN25817, transversal hardness measurements are made and the heat input to the workpiece is calculated. The results show that the critical gap is 0.1 mm for a laser weld alone. With hybrid welding, this can...... be increased to 0.6 mm, even at a welding speed of 3.5 m/min. The maximum welding speed with the hybrid process is comparable to laser welding alone, 4.5 m/min. The measured hardness is comparable to MIG welding, and this corresponds to a 33 percent reduction compared to laser welding alone. The heat input...

Prompt gamma analysis of fly ash, silica fume and Superpozz blended cement concrete specimen

Energy Technology Data Exchange (ETDEWEB)

Naqvi, A.A. [Department of Physics, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia)], E-mail: aanaqvi@kfupm.edu.sa; Garwan, M.A. [Department of Physics, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Maslehuddin, M. [Center for Engineering Research, Research Institute, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Nagadi, M.M. [Department of Physics, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Al-Amoudi, O.S.B. [Department of Civil Engineering, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Khateeb-ur-Rehman; Raashid, M. [Department of Physics, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia)

2009-09-15

Preventive measures against corrosion of reinforcing steel require making the concrete dense by adding pozzolanic materials, such as fly ash, silica fume, Superpozz, blast furnace slag, etc. to Portland cement. In order to obtain the desired strength and durability of concrete, it is desirable to monitor the concentration of the pozzolan in the blended cement concrete. Addition of pozzolan to blended cement changes the overall concentration of calcium and silicon in the blended cement concrete. The resulting variation in calcium and silicon gamma-ray yield ratio from blended cement concrete has found to have an inverse correlation with concentration of fly ash, silica fume, Superpozz, blast furnace slag in the blended cement concrete. For experimental verification of the correlation, intensities of calcium and silicon prompt gamma-ray due to capture of thermal neutrons in blended cement concrete samples containing 5-80% (by weight of cement) silica fume, fly ash and Superpozz were measured. The gamma-ray intensity ratio was measured from 6.42 MeV gamma-rays from calcium and 4.94 MeV gamma-ray from silicon. The experimentally measured values of calcium to silicon gamma-ray yield ratio in the fly ash, silica fume and Superpozz cement concrete specimens agree very well with the results of the Monte Carlo simulations.

Prompt gamma analysis of fly ash, silica fume and Superpozz blended cement concrete specimen

International Nuclear Information System (INIS)

Naqvi, A.A.; Garwan, M.A.; Maslehuddin, M.; Nagadi, M.M.; Al-Amoudi, O.S.B.; Khateeb-ur-Rehman,; Raashid, M.

2009-01-01

Preventive measures against corrosion of reinforcing steel require making the concrete dense by adding pozzolanic materials, such as fly ash, silica fume, Superpozz, blast furnace slag, etc. to Portland cement. In order to obtain the desired strength and durability of concrete, it is desirable to monitor the concentration of the pozzolan in the blended cement concrete. Addition of pozzolan to blended cement changes the overall concentration of calcium and silicon in the blended cement concrete. The resulting variation in calcium and silicon gamma-ray yield ratio from blended cement concrete has found to have an inverse correlation with concentration of fly ash, silica fume, Superpozz, blast furnace slag in the blended cement concrete. For experimental verification of the correlation, intensities of calcium and silicon prompt gamma-ray due to capture of thermal neutrons in blended cement concrete samples containing 5-80% (by weight of cement) silica fume, fly ash and Superpozz were measured. The gamma-ray intensity ratio was measured from 6.42 MeV gamma-rays from calcium and 4.94 MeV gamma-ray from silicon. The experimentally measured values of calcium to silicon gamma-ray yield ratio in the fly ash, silica fume and Superpozz cement concrete specimens agree very well with the results of the Monte Carlo simulations.

LASER WELDING WITH MICRO-JET COOLING FOR TRUCK FRAME WELDING

Directory of Open Access Journals (Sweden)

Jan PIWNIK

2017-12-01

Full Text Available The aim of this paper is to analyse the mechanical properties of the weld steel structure of car body truck frames after laser welding. The best welding conditions involve the use of proper materials and alloy elements in steel and filer materials, in addition to welding technology, state of stress and temperature of exploitation. We present for the first time the properties of steel track structures after laser welding with micro-jet cooling. Therefore, good selection of both welding parameters and micro-jet cooling parameters is very important to achieve a proper steel structure. In this study, the metallographic structure, tensile results and impact toughness of welded joints have been analysed in terms of welding parameters.

Forming Completely Penetrated Welded T-joints when Pulsed Arc Welding

Science.gov (United States)

Krampit, N. Yu; Krampit, M. A.; Sapozhkov, A. S.

2016-04-01

The paper is focused on revealing the influence of welding parameters on weld formation when pulsed arc welding. As an experimental sample a T-joint over 10 mm was selected. Welding was carried out in flat position, which required no edge preparation but provided mono-directional guaranteed root penetration. The following parameters of welding were subjected to investigation: gap in the joint, wire feed rate and incline angles of the torch along and across the weld axis. Technological recommendations have been made with respect to pulsed arc welding; the cost price of product manufacturing can be reduced on their basis due to reduction of labor input required by machining, lowering consumption of welding materials and electric power.

Resistance welding

DEFF Research Database (Denmark)

Bay, Niels; Zhang, Wenqi; Rasmussen, Mogens H.

2003-01-01

Resistance welding comprises not only the well known spot welding process but also more complex projection welding operations, where excessive plastic deformation of the weld point may occur. This enables the production of complex geometries and material combinations, which are often not possible...... to weld by traditional spot welding operations. Such joining processes are, however, not simple to develop due to the large number of parameters involved. Development has traditionally been carried out by large experimental investigations, but the development of a numerical programme system has changed...... this enabling prediction of the welding performance in details. The paper describes the programme in short and gives examples on industrial applications. Finally investigations of causes for failure in a complex industrial joint of two dissimilar metals are carried out combining numerical modelling...

Cu-Fe welding techniques by electromagnetic and electron beam welding processes

International Nuclear Information System (INIS)

Kumar, Satendra; Saroj, P.C.; Kulkarni, M.R.; Sharma, A.; Rajawat, R.K.; Saha, T.K.

2015-01-01

Electromagnetic welding being a solid state welding process has been found suitable for welding Copper and Iron which are conventionally very tricky. Owing to good electrical conductivity of both copper and iron, they are best suited combination for EM welding. For the experimental conditions presented above, 1.0 mm wall thickness of Cu tube was lap welded to Fe disc. A heavy duty four disc stainless steel coil was used for electromagnetic welding of samples. MSLD of the welded samples indicated leak proof joints. Metallographic examination of the welds also revealed defect free interfaces. Electron beam welding is also a non-conventional welding process used for joining dissimilar materials. Autogenous welding of the above specimen was carried out by EBW method for the sake of comparison. A characterization analysis of the above mentioned joining processes will be discussed in the paper. (author)

Reporting a sudden death due to accidental gasoline inhalation.

Science.gov (United States)

Martínez, María Antonia; Ballesteros, Salomé; Alcaraz, Rafael

2012-02-10

The investigation of uncertain fatalities requires accurate determination of the cause of death, with assessment of all factors that may have contributed to it. Gasoline is a complex and highly variable mixture of aliphatic and aromatic hydrocarbons that can lead to cardiac arrhythmias due to sensitization of the myocardium to catecholamines or acts as a simple asphyxiant if the vapors displace sufficient oxygen from the breathing atmosphere. This work describes a sudden occupational fatality involving gasoline. The importance of this petroleum distillate detection and its quantitative toxicological significance is discussed using a validated analytical method. A 51 year-old Caucasian healthy man without significant medical history was supervising the repairs of the telephone lines in a manhole near to a gas station. He died suddenly after inhaling gasoline vapors from an accidental leak. Extensive blistering and peeling of skin were observed on the skin of the face, neck, anterior chest, upper and lower extremities, and back. The internal examination showed a strong odor of gasoline, specially detected in the respiratory tract. The toxicological screening and quantitation of gasoline was performed by means of gas chromatography with flame ionization detector and confirmation was performed using gas chromatography-mass spectrometry. Disposition of gasoline in different tissues was as follows: heart blood, 35.7 mg/L; urine, not detected; vitreous humor, 1.9 mg/L; liver, 194.7 mg/kg; lung, 147.6 mg/kg; and gastric content, 116,6 mg/L (2.7 mg total). Based upon the toxicological data along with the autopsy findings, the cause of death was determined to be gasoline poisoning and the manner of death was accidental. We would like to alert on the importance of testing for gasoline, and in general for volatile hydrocarbons, in work-related sudden deaths involving inhalation of hydrocarbon vapors and/or exhaust fumes. Copyright © 2011 Elsevier Ireland Ltd. All rights

Deconvoluting the Friction Stir Weld Process for Optimizing Welds

Science.gov (United States)

Schneider, Judy; Nunes, Arthur C.

2008-01-01

In the friction stir welding process, the rotating surfaces of the pin and shoulder contact the weld metal and force a rotational flow within the weld metal. Heat, generated by the metal deformation as well as frictional slippage with the contact surface, softens the metal and makes it easier to deform. As in any thermo-mechanical processing of metal, the flow conditions are critical to the quality of the weld. For example, extrusion of metal from under the shoulder of an excessively hot weld may relax local pressure and result in wormhole defects. The trace of the weld joint in the wake of the weld may vary geometrically depending upon the flow streamlines around the tool with some geometry more vulnerable to loss of strength from joint contamination than others. The material flow path around the tool cannot be seen in real time during the weld. By using analytical "tools" based upon the principles of mathematics and physics, a weld model can be created to compute features that can be observed. By comparing the computed observations with actual data, the weld model can be validated or adjusted to get better agreement. Inputs to the model to predict weld structures and properties include: hot working properties ofthe metal, pin tool geometry, travel rate, rotation and plunge force. Since metals record their prior hot working history, the hot working conditions imparted during FSW can be quantified by interpreting the final microstructure. Variations in texture and grain size result from variations in the strain accommodated at a given strain rate and temperature. Microstructural data from a variety of FSWs has been correlated with prior marker studies to contribute to our understanding of the FSW process. Once this stage is reached, the weld modeling process can save significant development costs by reducing costly trial-and-error approaches to obtaining quality welds.

Effects of Fusion Tack Welds on Self-Reacting Friction Stir Welds

Science.gov (United States)

Nunes, A. C., Jr.; Pendleton, M. L.; Brooke, S. A.; Russell, C. K.

2012-01-01

In order to know whether fusion tack welds would affect the strength of self-reacting friction stir seam welds in 2195-T87 aluminum alloy, the fracture stresses of 144 tensile test coupons cut from 24 welded panels containing segments of friction stir welds were measured. Each of the panels was welded under unique processing conditions. A measure of the effect of the tack welds for each panel was devised. An analysis of the measures of the tack weld effect supported the hypothesis that fusion tack welds do not affect the strength of self-reacting friction stir welds to a 5% level of confidence.

Residual stress reduction in the penetration nozzle weld joint by overlay welding

International Nuclear Information System (INIS)

Jiang, Wenchun; Luo, Yun; Wang, B.Y.; Tu, S.T.; Gong, J.M.

2014-01-01

Highlights: • Residual stress reduction in penetration weld nozzle by overlay welding was studied. • The overlay weld can decrease the residual stress in the weld root. • Long overlay welding is proposed in the actual welding. • Overlay weld to decrease residual stress is more suitable for thin nozzle. - Abstract: Stress corrosion cracking (SCC) in the penetration nozzle weld joint endangers the structural reliability of pressure vessels in nuclear and chemical industries. How to decrease the residual stress is very critical to ensure the structure integrity. In this paper, a new method, which uses overlay welding on the inner surface of nozzle, is proposed to decrease the residual stresses in the penetration joint. Finite element simulation is used to study the change of weld residual stresses before and after overlay welding. It reveals that this method can mainly decrease the residual stress in the weld root. Before overlay welding, large tensile residual stresses are generated in the weld root. After overlay weld, the tensile hoop stress in weld root has been decreased about 45%, and the radial stress has been decreased to compressive stress, which is helpful to decrease the susceptibility to SCC. With the increase of overlay welding length, the residual stress in weld root has been greatly decreased, and thus the long overlay welding is proposed in the actual welding. It also finds that this method is more suitable for thin nozzle rather than thick nozzle

Welding processes handbook

CERN Document Server

Weman, Klas

2011-01-01

Offers an introduction to the range of available welding technologies. This title includes chapters on individual techniques that cover principles, equipment, consumables and key quality issues. It includes material on such topics as the basics of electricity in welding, arc physics, and distortion, and the weldability of particular metals.$bThe first edition of Welding processes handbook established itself as a standard introduction and guide to the main welding technologies and their applications. This new edition has been substantially revised and extended to reflect the latest developments. After an initial introduction, the book first reviews gas welding before discussing the fundamentals of arc welding, including arc physics and power sources. It then discusses the range of arc welding techniques including TIG, plasma, MIG/MAG, MMA and submerged arc welding. Further chapters cover a range of other important welding technologies such as resistance and laser welding, as well as the use of welding techniqu...

Welding Curriculum.

Science.gov (United States)

Alaska State Dept. of Education, Juneau. Div. of Adult and Vocational Education.

This competency-based curriculum guide is a handbook for the development of welding trade programs. Based on a survey of Alaskan welding employers, it includes all competencies a student should acquire in such a welding program. The handbook stresses the importance of understanding the principles associated with the various elements of welding.…

LASER WELDING WITH MICRO-JET COOLING FOR TRUCK FRAME WELDING

OpenAIRE

Jan PIWNIK; Bożena SZCZUCKA-LASOTA; Tomasz WĘGRZYN; Wojciech MAJEWSKI

2017-01-01

The aim of this paper is to analyse the mechanical properties of the weld steel structure of car body truck frames after laser welding. The best welding conditions involve the use of proper materials and alloy elements in steel and filer materials, in addition to welding technology, state of stress and temperature of exploitation. We present for the first time the properties of steel track structures after laser welding with micro-jet cooling. Therefore, good selection of both welding paramet...

Thermal Stir Welding: A New Solid State Welding Process

Science.gov (United States)

Ding, R. Jeffrey

2003-01-01

Thermal stir welding is a new welding process developed at NASA's Marshall Space Flight Center in Huntsville, AL. Thermal stir welding is similar to friction stir welding in that it joins similar or dissimilar materials without melting the parent material. However, unlike friction stir welding, the heating, stirring and forging elements of the process are all independent of each other and are separately controlled. Furthermore, the heating element of the process can be either a solid-state process (such as a thermal blanket, induction type process, etc), or, a fusion process (YG laser, plasma torch, etc.) The separation of the heating, stirring, forging elements of the process allows more degrees of freedom for greater process control. This paper introduces the mechanics of the thermal stir welding process. In addition, weld mechanical property data is presented for selected alloys as well as metallurgical analysis.

Inhalants in Peru.

Science.gov (United States)

Lerner, R; Ferrando, D

1995-01-01

In Peru, the prevalence and consequences of inhalant abuse appear to be low in the general population and high among marginalized children. Inhalant use ranks third in lifetime prevalence after alcohol and tobacco. Most of the use appears to be infrequent. Among marginalized children, that is, children working in the streets but living at home or children living in the street, the problem of inhalant abuse is a serious problem. Among children working in the streets but living at home, the lifetime prevalence rate for inhalant abuse is high, ranging from 15 to 45 percent depending on the study being cited. For children living in the streets, the use of inhalant is even more severe. As mentioned earlier in this chapter, most of these street children use inhalants on a daily basis. The lack of research on the problem of inhalant abuse is a serious impediment to development of intervention programs and strategies to address this problem in Peru. Epidemiologic and ethnographic research on the nature and extent of inhalant abuse are obvious prerequisites to targeted treatment and preventive intervention programs. The urgent need for current and valid data is underscored by the unique vulnerability of the youthful population at risk and the undisputed harm that results from chronic abuse of inhalants. Nonetheless, it is important to mention several programs that work with street children. Some, such as the Information and Education Center for the Prevention of Drug Abuse, Generation, and Centro Integracion de Menores en Abandono have shelters where street children are offered transition to a less marginal lifestyle. Teams of street educators provide the children with practical solutions and gain their confidence, as well as offer them alternative socialization experiences to help them survive the streets and avoid the often repressive and counterproductive environments typical of many institutions. Most of the children who go through these programs tend to abandon

Association between cooking oil fume exposure and lung cancer among Chinese nonsmoking women: a meta-analysis

Directory of Open Access Journals (Sweden)

Xue Y

2016-05-01

Full Text Available Yingbo Xue, Ying Jiang, Shan Jin, Yong Li Department of Oncology, Guizhou Provincial People’s Hospital, Guiyang, Guizhou, People’s Republic of China Abstract: Lung cancer has been the main cause of cancer death around the world. Cigarette smoking has been identified as a risk factor for lung cancer in males. However, the etiological factors in nonsmoking women remain elusive. A meta-analysis was conducted to evaluate the relationship between cooking oil fume exposure and lung cancer among Chinese nonsmoking women. Thirteen articles containing three population-based case–control and ten hospital-based case–control studies were included in this meta-analysis. These studies with a total of 3,596 lung cancer women and 6,082 healthy controls were analyzed by RevMan 5.3. Fixed effects model or random effects model was used to obtain pooled estimates of risk ratio. The risk ratios with a 95% CI were 1.74 (95% CI =1.57–1.94 and 2.11 (95% CI =1.54–2.89, respectively. Cooking oil fume exposure as well as not using a kitchen ventilator when cooking was significantly associated with lung cancer among nonsmoking women (Z=10.07, P<0.00001; Z=4.65, P<0.00001. Cooking oil fume exposure, especially lacking a fume extractor, may increase the risk of lung cancer among Chinese nonsmoking women. Keywords: cooking oil fume exposure, lung cancer, meta-analysis, nonsmoking women 

Sustainability of Welding Process through Bobbin Friction Stir Welding

Science.gov (United States)

Sued, M. K.; Samsuri, S. S. M.; Kassim, M. K. A. M.; Nasir, S. N. N. M.

2018-03-01

Welding process is in high demand, which required a competitive technology to be adopted. This is important for sustaining the needs of the joining industries without ignoring the impact of the process to the environment. Friction stir welding (FSW) is stated to be benefitting the environment through low energy consumption, which cannot be achieved through traditional arc welding. However, this is not well documented, especially for bobbin friction stir welding (BFSW). Therefore, an investigation is conducted by measuring current consumption of the machine during the BFSW process. From the measurement, different phases of BFSW welding process and its electrical demand are presented. It is found that in general total energy in BFSW is about 130kW inclusive of all identified process phases. The phase that utilise for joint formation is in weld phase that used the highest total energy of 120kWs. The recorded total energy is still far below the traditional welding technology and the conventional friction stir welding (CFSW) energy demand. This indicates that BFSW technology with its vast benefit able to sustain the joining technology in near future.

Enabling high speed friction stir welding of aluminum tailor welded blanks

Science.gov (United States)

Hovanski, Yuri

Current welding technologies for production of aluminum tailor-welded blanks (TWBs) are utilized in low-volume and niche applications, and have yet to be scaled for the high-volume vehicle market. This study targeted further weight reduction, part reduction, and cost savings by enabling tailor-welded blank technology for aluminum alloys at high-volumes. While friction stir welding (FSW) has traditionally been applied at linear velocities less than one meter per minute, high volume production applications demand the process be extended to higher velocities more amenable to cost sensitive production environments. Unfortunately, weld parameters and performance developed and characterized at low to moderate welding velocities do not directly translate to high speed linear friction stir welding. Therefore, in order to facilitate production of high volume aluminum FSW components, parameters were developed with a minimum welding velocity of three meters per minute. With an emphasis on weld quality, welded blanks were evaluated for post-weld formability using a combination of numerical and experimental methods. Evaluation across scales was ultimately validated by stamping full-size production door inner panels made from dissimilar thickness aluminum tailor-welded blanks, which provided validation of the numerical and experimental analysis of laboratory scale tests.

Performance of soft clay stabilized with sand columns treated by silica fume

Directory of Open Access Journals (Sweden)

Samueel Zeena

2018-01-01

Full Text Available In many road construction projects, if weak soil exists, then uncontrollable settlement and critical load carrying capacity are major difficult problems to the safety and serviceability of roads in these areas. Thus ground improvement is essential to achieve the required level of performance. The paper presents results of the tests of four categories. First category was performed on saturated soft bed of clay without any treatment, the second category shed light on the improvement achieved in loading carrying capacity and settlement as a result of reinforcing with conventional sand columns at area replacement ratio = 0.196. The third set investigates the bed reinforced by sand columns stabilized with dry silica fume at different percentages (3, 5 and 7% and the fourth set investigates the behavior of sand columns treated with slurry silica fume at two percentages (10 and 12%. All sand columns models were constructed at (R.D= 60%. Model tests were performed on bed of saturated soil prepared at undrained shear strength between 16-20 kPa for all models. For all cases, the model test was loaded gradually by stress increments up to failure. Stress deformation measurements are recorded and analyzed in terms of bearing improvement ratio and settlement reduction ratio. Optimum results were indicated from soil treated with sand columns stabilized with 7% dry silica fume at medium state reflecting the highest bearing improvement ratio (3.04 and the settlement reduction ratio (0.09 after 7 days curing. While soil treated with sand columns stabilized with 10% slurry silica fume provided higher bearing improvement ratio 3.13 with lower settlement reduction ratio of 0.57 after 7-days curing.

The Influence of Friction Stir Weld Tool Form and Welding Parameters on Weld Structure and Properties: Nugget Bulge in Self-Reacting Friction Stir Welds

Science.gov (United States)

Schneider, Judy; Nunes, Arthur C., Jr.; Brendel, Michael S.

2010-01-01

Although friction stir welding (FSW) was patented in 1991, process development has been based upon trial and error and the literature still exhibits little understanding of the mechanisms determining weld structure and properties. New concepts emerging from a better understanding of these mechanisms enhance the ability of FSW engineers to think about the FSW process in new ways, inevitably leading to advances in the technology. A kinematic approach in which the FSW flow process is decomposed into several simple flow components has been found to explain the basic structural features of FSW welds and to relate them to tool geometry and process parameters. Using this modelling approach, this study reports on a correlation between the features of the weld nugget, process parameters, weld tool geometry, and weld strength. This correlation presents a way to select process parameters for a given tool geometry so as to optimize weld strength. It also provides clues that may ultimately explain why the weld strength varies within the sample population.

Hydrazine inhalation hepatotoxicity.

Science.gov (United States)

Kao, Yung Hsiang; Chong, C H; Ng, W T; Lim, D

2007-10-01

Abstract Hydrazine is a hazardous chemical commonly used as a reactant in rocket and jet fuel cells. Animal studies have demonstrated hepatic changes after hydrazine inhalation. Human case reports of hydrazine inhalation hepatotoxicity are rare. We report a case of mild hepatotoxicity following brief hydrazine vapour inhalation in a healthy young man, which resolved completely on expectant management.

SIMS depth profiling of working environment nanoparticles

Science.gov (United States)

Konarski, P.; Iwanejko, I.; Mierzejewska, A.

2003-01-01

Morphology of working environment nanoparticles was analyzed using sample rotation technique in secondary ion mass spectrometry (SIMS). The particles were collected with nine-stage vacuum impactor during gas tungsten arc welding (GTAW) process of stainless steel and shielded metal arc welding (SMAW) of mild steel. Ion erosion of 300-400 nm diameter nanoparticles attached to indium substrate was performed with 2 keV, 100 μm diameter, Ar + ion beam at 45° ion incidence and 1 rpm sample rotation. The results show that both types of particles have core-shell morphology. A layer of fluorine, chlorine and carbon containing compounds covers stainless steel welding fume particles. The cores of these particles are enriched in iron, manganese and chromium. Outer shell of mild steel welding fume particles is enriched in carbon, potassium, chlorine and fluorine, while the deeper layers of these nanoparticles are richer in main steel components.

SIMS depth profiling of working environment nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Konarski, P.; Iwanejko, I.; Mierzejewska, A

2003-01-15

Morphology of working environment nanoparticles was analyzed using sample rotation technique in secondary ion mass spectrometry (SIMS). The particles were collected with nine-stage vacuum impactor during gas tungsten arc welding (GTAW) process of stainless steel and shielded metal arc welding (SMAW) of mild steel. Ion erosion of 300-400 nm diameter nanoparticles attached to indium substrate was performed with 2 keV, 100 {mu}m diameter, Ar{sup +} ion beam at 45 deg. ion incidence and 1 rpm sample rotation. The results show that both types of particles have core-shell morphology. A layer of fluorine, chlorine and carbon containing compounds covers stainless steel welding fume particles. The cores of these particles are enriched in iron, manganese and chromium. Outer shell of mild steel welding fume particles is enriched in carbon, potassium, chlorine and fluorine, while the deeper layers of these nanoparticles are richer in main steel components.

Automatic orbital GTAW welding: Highest quality welds for tomorrow's high-performance systems

Science.gov (United States)

Henon, B. K.

1985-01-01

Automatic orbital gas tungsten arc welding (GTAW) or TIG welding is certain to play an increasingly prominent role in tomorrow's technology. The welds are of the highest quality and the repeatability of automatic weldings is vastly superior to that of manual welding. Since less heat is applied to the weld during automatic welding than manual welding, there is less change in the metallurgical properties of the parent material. The possibility of accurate control and the cleanliness of the automatic GTAW welding process make it highly suitable to the welding of the more exotic and expensive materials which are now widely used in the aerospace and hydrospace industries. Titanium, stainless steel, Inconel, and Incoloy, as well as, aluminum can all be welded to the highest quality specifications automatically. Automatic orbital GTAW equipment is available for the fusion butt welding of tube-to-tube, as well as, tube to autobuttweld fittings. The same equipment can also be used for the fusion butt welding of up to 6 inch pipe with a wall thickness of up to 0.154 inches.

Isothermal model investigation of fume extraction systems for the scrap burner at Appleby Frodingham

Energy Technology Data Exchange (ETDEWEB)

Robinson, D.

1976-08-01

Model tests have been made on three suggested schemes for improving the efficiency of fume collection on the scrap burning installation in the Anchor BOS plant at Appleby Frodingham. In particular the usefulness of air curtains as a means of containing the fume has been examined. CO/sub 2/ tracer measurements, and photographs using smoke for visualization have allowed the assessment of the collection efficiencies of the three schemes, and some alterative solutions have been investigated using similar methods. (GRA)

Evaluation of one-step luminescent cyanoacrylate fuming.

Science.gov (United States)

Khuu, Alicia; Chadwick, Scott; Spindler, Xanthe; Lam, Rolanda; Moret, Sébastien; Roux, Claude

2016-06-01

One-step luminescent cyanoacrylates have recently been introduced as an alternative to the conventional cyanoacrylate fuming methods. These new techniques do not require the application of a luminescent post-treatment in order to enhance cyanoacrylate-developed fingermarks. In this study, three one-step polymer cyanoacrylates: CN Yellow Crystals (Aneval Inc.), PolyCyano UV (Foster+Freeman Ltd.) and PECA Multiband (BVDA), and one monomer cyanoacrylate: Lumikit™ (Crime Scene Technology), were evaluated against a conventional two-step cyanoacrylate fuming method (Cyanobloom (Foster+Freeman Ltd.) with rhodamine 6G stain). The manufacturers' recommended conditions or conditions compatible with the MVC™ 1000/D (Foster+Freeman Ltd.) were assessed with fingermarks aged for up to 8 weeks on non-porous and semi-porous substrates. Under white light, Cyanobloom generally gave better development than the one-step treatments across the substrates. Similarly when viewed under the respective luminescent conditions, Cyanobloom with rhodamine 6G stain resulted in improved contrast against the one-step treatments except on polystyrene, where PolyCyano UV and PECA Multiband gave better visualisation. Rhodamine 6G post-treatment of one-step samples did not significantly enhance the contrast of any of the one-step treatments against Cyanobloom/rhodamine 6G-treated samples. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Influence of Welding Process and Post Weld Heat Treatment on Microstructure and Pitting Corrosion Behavior of Dissimilar Aluminium Alloy Welds

Science.gov (United States)

Venkata Ramana, V. S. N.; Mohammed, Raffi; Madhusudhan Reddy, G.; Srinivasa Rao, K.

2018-03-01

Welding of dissimilar Aluminum alloy welds is becoming important in aerospace, shipbuilding and defence applications. In the present work, an attempt has been made to weld dissimilar aluminium alloys using conventional gas tungsten arc welding (GTAW) and friction stir welding (FSW) processes. An attempt was also made to study the effect of post weld heat treatment (T4 condition) on microstructure and pitting corrosion behaviour of these welds. Results of the present investigation established the differences in microstructures of the base metals in T4 condition and in annealed conditions. It is evident that the thickness of the PMZ is relatively more on AA2014 side than that of AA6061 side. In FS welds, lamellar like shear bands are well noticed on the top of the stir zone. The concentration profile of dissimilar friction stir weld in T4 condition revealed that no diffusion has taken place at the interface. Poor Hardness is observed in all regions of FS welds compared to that of GTA welds. Pitting corrosion resistance of the dissimilar FS welds in all regions was improved by post weld heat treatment.

A control system for uniform bead in fillet arc welding on tack welds

International Nuclear Information System (INIS)

Kim, Jae Woong; Lee, Jun Young

2008-01-01

Positioning a workpiece accurately and preventing weld distortion, tack welding is often adopted before main welding in the construction of welded structures. However, this tack weld deteriorates the final weld bead profile, so that the grinding process is usually performed for a uniform weld bead profile. In this study, a control system for uniform weld bead is proposed for the fillet arc welding on tack welds. The system consists of GMA welding machine, torch manipulator, laser vision sensor for measuring the tack weld size and the database for optimal welding conditions. Experiments have been performed for constructing the database and for evaluating the control capability of the system. It has been shown that the system has the capability to smooth the bead at the high level of quality

Torque Measurement of Welding of Endplug-Endplate using Multi-pin Remote Welding System

Energy Technology Data Exchange (ETDEWEB)

Koo, Dae-Seo; Kim, Soo-Sung; Park, Geun-Il; Lee, Jung-Won; Song, Kee-Chan [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

2006-07-01

As fuel bundles in PHWR irradiates, inner pressure in claddings of fuel rods increases owing to outer pressure and fission products of nuclear fissions. Because of leak possibility of welding between cladding and end plug, this welding part connects with safety of nuclear fuel rods. Because of importance of this welding part, weldability of end plug-cladding of nuclear fuel rods is continually researched. Welding method for research and commercialization is classified as melting, solid type welding or resistance welding. End plug cladding welding of nuclear fuel rods in PHWR takes advantage of resistance upset butt welding using multicycle mode. This method makes weld flash and shapes re-entrant corner owing to welding heat due to resistivity, contact resistance of cladding-end plug, and inelasticity deformation due to pressure. Welding part between cladding and end plug receives stresses and makes small cracks. In this study, remote welding system for multi-pin assembly was designed, fabricated and welding specimens of end plug-endplate were made using electrical resistance method. The torques of welding between end plug and endplate were measured. These results on welding current, pressure of main electrode and pressure of branch electrode were analyzed. Weldability between end plug and endplate was confirmed through metallographic examinations. In the future, optimal welding examinations due to welding current, welding pressure and welding time will be performed to improve weldability of end plug-endplate.

Advantages of new micro-jet welding technology on weld microstructure control

Directory of Open Access Journals (Sweden)

Jan PIWNIK

2013-01-01

Full Text Available An innovative apparatus to welding process with micro-jet cooling of the weld made it possible to carry out technological tests, which have proved theoretical considerations about this problem. This project gives real opportunities for professional development in the field of welding with controlling the parameters of weld structure. These tests have proved that the new micro-jet technology has the potential for growth. It may be great achievement of welding technology in order to increase weld metal strength. The new technology with micro-jet cooling may have many practical applications in many fields, for example such as in the transport industry or to repair damaged metal elements. The advantages of the new device over the traditional system are the ability to control the structure of the weld, the weld mechanical performance increases and improve the quality of welded joints.

Effect of silica fume on the fresh and hardened properties of fly ash-based self-compacting geopolymer concrete

Science.gov (United States)

Memon, Fareed Ahmed; Nuruddin, Muhd Fadhil; Shafiq, Nasir

2013-02-01

The effect of silica fume on the fresh and hardened properties of fly ash-based self-compacting geopolymer concrete (SCGC) was investigated in this paper. The work focused on the concrete mixes with a fixed water-to-geopolymer solid (W/Gs) ratio of 0.33 by mass and a constant total binder content of 400 kg/m3. The mass fractions of silica fume that replaced fly ash in this research were 0wt%, 5wt%, 10wt%, and 15wt%. The workability-related fresh properties of SCGC were assessed through slump flow, V-funnel, and L-box test methods. Hardened concrete tests were limited to compressive, splitting tensile and flexural strengths, all of which were measured at the age of 1, 7, and 28 d after 48-h oven curing. The results indicate that the addition of silica fume as a partial replacement of fly ash results in the loss of workability; nevertheless, the mechanical properties of hardened SCGC are significantly improved by incorporating silica fume, especially up to 10wt%. Applying this percentage of silica fume results in 4.3% reduction in the slump flow; however, it increases the compressive strength by 6.9%, tensile strength by 12.8% and flexural strength by 11.5%.

TECHNOLOGICAL ISSUES IN MECHANISED FEED WIG/TIG WELDING SURFACING OF WELDING

Directory of Open Access Journals (Sweden)

BURCA Mircea

2016-09-01

manual welding tests in the light of using the process for welding surfacing being known that in such applications mechanised operations are recommended whenever possible given the latter strengths i.e. increased productivity and quality deposits. The research also aims at achieving a comparative a study between wire mechanised feed based WIG manual welding and the manual rod entry based manual welding in terms of geometry deposits, deposits aesthetics, operating technique, productivity, etc . In this regard deposits were made by means of two welding procedures, and subsequently welding surfacing was made with the optimum values of the welding parameters in this case.

Association between cooking oil fume exposure and lung cancer among Chinese nonsmoking women: a meta-analysis.

Science.gov (United States)

Xue, Yingbo; Jiang, Ying; Jin, Shan; Li, Yong

2016-01-01

Lung cancer has been the main cause of cancer death around the world. Cigarette smoking has been identified as a risk factor for lung cancer in males. However, the etiological factors in nonsmoking women remain elusive. A meta-analysis was conducted to evaluate the relationship between cooking oil fume exposure and lung cancer among Chinese nonsmoking women. Thirteen articles containing three population-based case-control and ten hospital-based case-control studies were included in this meta-analysis. These studies with a total of 3,596 lung cancer women and 6,082 healthy controls were analyzed by RevMan 5.3. Fixed effects model or random effects model was used to obtain pooled estimates of risk ratio. The risk ratios with a 95% CI were 1.74 (95% CI =1.57-1.94) and 2.11 (95% CI =1.54-2.89), respectively. Cooking oil fume exposure as well as not using a kitchen ventilator when cooking was significantly associated with lung cancer among nonsmoking women (Z=10.07, Poil fume exposure, especially lacking a fume extractor, may increase the risk of lung cancer among Chinese nonsmoking women.

Welding Penetration Control of Fixed Pipe in TIG Welding Using Fuzzy Inference System

Science.gov (United States)

Baskoro, Ario Sunar; Kabutomori, Masashi; Suga, Yasuo

This paper presents a study on welding penetration control of fixed pipe in Tungsten Inert Gas (TIG) welding using fuzzy inference system. The welding penetration control is essential to the production quality welds with a specified geometry. For pipe welding using constant arc current and welding speed, the bead width becomes wider as the circumferential welding of small diameter pipes progresses. Having welded pipe in fixed position, obviously, the excessive arc current yields burn through of metals; in contrary, insufficient arc current produces imperfect welding. In order to avoid these errors and to obtain the uniform weld bead over the entire circumference of the pipe, the welding conditions should be controlled as the welding proceeds. This research studies the intelligent welding process of aluminum alloy pipe 6063S-T5 in fixed position using the AC welding machine. The monitoring system used a charge-coupled device (CCD) camera to monitor backside image of molten pool. The captured image was processed to recognize the edge of molten pool by image processing algorithm. Simulation of welding control using fuzzy inference system was constructed to simulate the welding control process. The simulation result shows that fuzzy controller was suitable for controlling the welding speed and appropriate to be implemented into the welding system. A series of experiments was conducted to evaluate the performance of the fuzzy controller. The experimental results show the effectiveness of the control system that is confirmed by sound welds.

Versatile Friction Stir Welding/Friction Plug Welding System

Science.gov (United States)

Carter, Robert

2006-01-01

A proposed system of tooling, machinery, and control equipment would be capable of performing any of several friction stir welding (FSW) and friction plug welding (FPW) operations. These operations would include the following: Basic FSW; FSW with automated manipulation of the length of the pin tool in real time [the so-called auto-adjustable pin-tool (APT) capability]; Self-reacting FSW (SRFSW); SR-FSW with APT capability and/or real-time adjustment of the distance between the front and back shoulders; and Friction plug welding (FPW) [more specifically, friction push plug welding] or friction pull plug welding (FPPW) to close out the keyhole of, or to repair, an FSW or SR-FSW weld. Prior FSW and FPW systems have been capable of performing one or two of these operations, but none has thus far been capable of performing all of them. The proposed system would include a common tool that would have APT capability for both basic FSW and SR-FSW. Such a tool was described in Tool for Two Types of Friction Stir Welding (MFS- 31647-1), NASA Tech Briefs, Vol. 30, No. 10 (October 2006), page 70. Going beyond what was reported in the cited previous article, the common tool could be used in conjunction with a plug welding head to perform FPW or FPPW. Alternatively, the plug welding head could be integrated, along with the common tool, into a FSW head that would be capable of all of the aforementioned FSW and FPW operations. Any FSW or FPW operation could be performed under any combination of position and/or force control.

Toxicological Investigation of Acute Carbon Monoxide Poisoning in Four Occupants of a Fuming Sport Utility Vehicle

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Martin Nnoli

2014-11-01

Full Text Available Background: This toxicological investigation involves a report on the death of four occupants of a sport utility vehicle on one of the major busy Federal roads of Nigeria where they were held for up to three hours in a traffic jam while the car was steaming. Methods: Autopsy was executed using the standard procedure and toxicological analysis was done using simple spectrophotometric method to establish the level of carboxyhaemoglobin (HbCO in peripheral blood in the four occupants. Results: The autopsy report indicated generalized cyanosis, sub-conjuctival hemorrhages, marked laryngo-trachea edema with severe hyperemia with frothy fluid discharges characteristic of carbon monoxide poisoning. Toxicological report of the level of HbCO in part per million (ppm in the peripheral blood of the four occupants was A= 650 ppm; B= 500 ppm; C= 480 ppm, and D= 495 ppm against the maximum permissible level of 50 ppm. Conclusion: The sudden death of the four occupants was due to excessive inhalation of the carbon monoxide gas from the exhaust fumes leaking into the cabin of the car. The poor road network, numerous potholes, and traffic jam in most of roads in Nigeria could have exacerbated a leaky exhaust of the smoky second hand SUV car leading to the acute carbon monoxide poisoning.

Hepatotoxic and Nephrotoxic Effects of Petroleum Fumes on Petrol ...

African Journals Online (AJOL)

The present study was conducted to evaluate the hepatotoxic and nephrotoxic effects of petroleum fumes on male and female petrol attendants. Investigations had been carried out on thirty (30) adult petrol attendants from different filling stations in Ibadan metropolis of Nigeria with ten (10) healthy adults as control. All the ...

Effect of Welding Parameters on Dilution and Weld Bead Geometry in Cladding

Institute of Scientific and Technical Information of China (English)

无

2007-01-01

The effect of pulsed gas metal arc welding (GMAW) variables on the dilution and weld bead geometry in cladding X65 pipeline steel with 316L stainless steel was studied. Using a full factorial method, a series of experiments were carried out to know the effect of wire feed rate, welding speed, distance between gas nozzle and plate, and the vertical angle of welding on dilution and weld bead geometry. The findings indicate that the dilution of weld metal and its dimension i.e. width, height and depth increase with the feed rate, but the contact angle of the bead decreases first and then increases. Meantime, welding speed has an opposite effect except for dilution. There is an interaction effect between welding parameters at the contact angle. The results also show forehand welding or decreasing electrode extension decrease the angle of contact. Finally,a mathematical model is contrived to highlight the relationship between welding variables with dilution and weld bead geometry.

Modeling of welded bead profile for rapid prototyping by robotic MAG welding

Institute of Scientific and Technical Information of China (English)

CAO Yong; ZHU Sheng; WANG Tao; WANG Wanglong

2009-01-01

As a deposition technology, robotic metal active gas(MAG) welding has shown new promise for rapid prototyping (RP) of metallic parts. During the process of metal forming using robotic MAG welding, sectional profile of single-pass welded bead is critical to formed accuracy and quality of metal pans. In this paper, the experiments of single-pass welded bead for rapid prototyping using robotic MAG welding were carried out. The effect of some edge detectors on the cross-sectional edge of welded bead was discussed and curve fitting was applied using leat square fitting. Consequently, the mathematical model of welded bead profile was developed. The experimental results show that good shape could be obtained under suitable welding parameters. Canny operawr is suitable to edge detection of welded bead profile, and the mathematical model of welded bead profile developed is approximately parabola.

In situ polymerization of L-Lactide in the presence of fumed silica

International Nuclear Information System (INIS)

Prebe, A.; Alcouffe, P.; Cassagnau, Ph.; Gerard, J.F.

2010-01-01

Chemiorheology, i.e. rheological changes during the polymerization, of a biosourced monomer, i.e. L-Lactide, containing fumed silica have been studied. For that purpose, the reaction was proceeded in situ between the plates of a dynamic rheometer. The polymerization kinetics was followed from the variation of the complex shear modulus versus reaction time. Moreover, at temperatures lower than the crystallization temperature, it was possible to follow the crystallization process while the polymerization takes place. Adding fumed silica particles into the monomer leads to the formation of a physical (percolated) network from particle-particle interactions, i.e. silica, in the L-Lactide probably hydrophilic interactions. The gel-like structure was kept while the polymerization as long as the strain remains low indicating that the silica particle network remains weak. Furthermore, the mechanism of the break down of the gel structure under large deformation as well as the recovery was discussed. It seems that the non-linearity effect of the nanocomposites stems in the silica inter-particle interactions. It was found that silica particles do not have any effect on the temperature of crystallization - molar mass relation but could act as nucleating agent. In situ polymerization of L-Lactide in the presence of 5 wt.% of modified fumed silica was carried out in a reactor. It was found that fumed hydrophilic silica leaded to a microcomposite with highly dense agglomerates in the polymer matrix whereas with a less hydrophilic silica it was possible to decrease the size of the agglomerates increasing the dispersion. The finest dispersion state was achieved with the 'initiating' functionalized silica leading to a 'grafting from' polymerization of the L-Lactide. Such functionalized silica leads to a nanoscale dispersion in a one-step bulk polymerization with only a few small agglomerates.

In situ polymerization of L-Lactide in the presence of fumed silica

Energy Technology Data Exchange (ETDEWEB)

Prebe, A. [Universite de Lyon, F-69361, Lyon (France); CNRS, UMR 5223, Ingenierie des Materiaux Polymeres, F-69622, Villeurbanne (France); Universite Claude Bernard Lyon 1, F-69622, Villeurbanne (France); INSA Lyon, F-69621, Villeurbanne (France); Alcouffe, P. [Universite de Lyon, F-69361, Lyon (France); CNRS, UMR 5223, Ingenierie des Materiaux Polymeres, F-69622, Villeurbanne (France); Universite Claude Bernard Lyon 1, F-69622, Villeurbanne (France); Cassagnau, Ph., E-mail: philippe.cassagnau@univ-lyon1.fr [Universite de Lyon, F-69361, Lyon (France); CNRS, UMR 5223, Ingenierie des Materiaux Polymeres, F-69622, Villeurbanne (France); Universite Claude Bernard Lyon 1, F-69622, Villeurbanne (France); Gerard, J.F. [Universite de Lyon, F-69361, Lyon (France); CNRS, UMR 5223, Ingenierie des Materiaux Polymeres, F-69622, Villeurbanne (France); INSA Lyon, F-69621, Villeurbanne (France)

2010-11-01

Chemiorheology, i.e. rheological changes during the polymerization, of a biosourced monomer, i.e. L-Lactide, containing fumed silica have been studied. For that purpose, the reaction was proceeded in situ between the plates of a dynamic rheometer. The polymerization kinetics was followed from the variation of the complex shear modulus versus reaction time. Moreover, at temperatures lower than the crystallization temperature, it was possible to follow the crystallization process while the polymerization takes place. Adding fumed silica particles into the monomer leads to the formation of a physical (percolated) network from particle-particle interactions, i.e. silica, in the L-Lactide probably hydrophilic interactions. The gel-like structure was kept while the polymerization as long as the strain remains low indicating that the silica particle network remains weak. Furthermore, the mechanism of the break down of the gel structure under large deformation as well as the recovery was discussed. It seems that the non-linearity effect of the nanocomposites stems in the silica inter-particle interactions. It was found that silica particles do not have any effect on the temperature of crystallization - molar mass relation but could act as nucleating agent. In situ polymerization of L-Lactide in the presence of 5 wt.% of modified fumed silica was carried out in a reactor. It was found that fumed hydrophilic silica leaded to a microcomposite with highly dense agglomerates in the polymer matrix whereas with a less hydrophilic silica it was possible to decrease the size of the agglomerates increasing the dispersion. The finest dispersion state was achieved with the 'initiating' functionalized silica leading to a 'grafting from' polymerization of the L-Lactide. Such functionalized silica leads to a nanoscale dispersion in a one-step bulk polymerization with only a few small agglomerates.

Fusion welding process

Science.gov (United States)

Thomas, Kenneth C.; Jones, Eric D.; McBride, Marvin A.

1983-01-01

A process for the fusion welding of nickel alloy steel members wherein a ferrite containing pellet is inserted into a cavity in one member and melted by a welding torch. The resulting weld nugget, a fusion of the nickel containing alloy from the members to be welded and the pellet, has a composition which is sufficiently low in nickel content such that ferrite phases occur within the weld nugget, resulting in improved weld properties. The steel alloys encompassed also include alloys containing carbon and manganese, considered nickel equivalents.

PEMANFAATAN LIMBAH SERBUK MARMER PADA BETON SEBAGAI BAHAN PENGGANTI SEBAGIAN SEMEN DENGAN VARIASI PENGGUNAAN SILICA FUME

Directory of Open Access Journals (Sweden)

Agil Fitri Handayani

2015-02-01

Full Text Available The Utilization of Marble Powder Waste in Concrete Ma­­­­­­­­terials as a Partial Material Substitution of Cement  with the Variation Use of Silica Fume. The purpose of this study was to determine the effect of marble powder and silica fume on the mechanical pro­per­ties of concrete. This study used an experimental design using 16 group of testing materials with variety types of mixtures between marble powder and silica fume 0.00; 5.00; 10.00; and 15.00%. The wa­ter-cement ratio was 0.50 and a low dosage of superplasticizer, which was 0.50%. The behavior of fresh concrete were calculated and the mechanical properties of concrete were tested on con­crete age of 28 days. The results showed the marble powder main com­position was Silicon Dioxide (SiO2 17.63% and Calcium Carbonate (CaCO3 2.73%. Mar­ble powder was more appropriate to be used as fillers than to be used as a partial substitution of ce­ment. The optimum mechanical properties of concrete was produced by the mixtures of 5.00% mar­ble powder  and 6.22% silica fume which resulted in compressive strength of 29.04 MPa.   Tujuan penelitian ini adalah untuk mengetahui pengaruh peng­gunaan ser­buk marmer dan silica fume terhadap sifat mekanik beton. Penelitian ini meng­gu­na­kan desain eksperimen dengan 16 kelompok benda uji dengan variasi ser­buk marmer dan silica fume 0,00; 5,00; 10,00; dan 15,00%. Faktor air semen di­gu­nakan 0,50 dan superplasticizer dengan dosis rendah 0,50%. Perilaku beton segar di­perhitungkan dan sifat mekanik beton diuji pada umur beton 28 hari. Hasil analisis me­nunjukkan kom­posisi utama serbuk marmer adalah Silikon Dioksida (SiO2 17,63% dan Kalsium Kar­bonat (CaCO3 2,73%. Serbuk marmer lebih tepat digunakan se­bagai bahan pe­ng­isi atau filler dari pada sebagai pengganti semen. Sifat mekanik be­ton optimum di­ha­sil­kan pada campuran serbuk marmer 5,00% dan silica fume 6,22% dengan kuat tekan be­ton yang dihasilkan  mencapai 29

Neuromotor function in ship welders after cessation of manganese exposure.

Science.gov (United States)

Wastensson, Gunilla; Sallsten, Gerd; Bast-Pettersen, Rita; Barregard, Lars

2012-08-01

The aim of the present study was to investigate whether previous long-term exposure to manganese (Mn) via inhalation of welding fumes can cause persistent impairment in neuromotor function even long after cessation of exposure. Quantitative tests of tremor, motor speed, manual dexterity, diadochokinesis, eye-hand coordination and postural stability were administered to 17 retired ship welders (mean age 69 years), with mean exposure time 28 years. The welders' exposure had ceased on average 18 years before the study. A cumulative exposure index (CEI) was calculated for each of the former welders. The welders were compared with 21 referents from the same shipyards (mean age was 66 years). Former welders performed less well than referents in the grooved pegboard test, and poorer performance was associated with CEI. The performance in most of the other neurobehavioral tests was similar between groups, but the welders tended to perform slightly better than the referents in tests demanding hand steadiness. The latter finding may be due to a training effect from their former working tasks or selection bias into or out of this occupation. In the present study of welders with previous welding fume exposure, former welders and referents performed similarly in most of the neurobehavioral tests. Previous adverse effects on the neuromotor system might have ceased, and decreased neuromotor function due to normal aging processes in both groups might have disguised any slight effect of previous Mn exposure. The poorer performance in the grooved pegboard test among welders may indicate an adverse effect on motor function of long-term exposure to Mn, but this finding has to be confirmed by other studies.

Effect of plasticizer and fumed silica on ionic conductivity behaviour ...

Indian Academy of Sciences (India)

behaviour of proton conducting polymer electrolytes containing different concentrations of hexafluorophosphoric acid (HPF6) in polyethylene oxide ... Polymer electrolytes; ionic conductivity; polyethylene oxide; plasticizer; fumed silica. 1. Introduction ..... is a rapid weight loss which could be due to the degradation of polymer ...

MAG narrow gap welding - an economic way to minimize welding expenses

International Nuclear Information System (INIS)

Kast, W.; Scholz, E.; Weyland, F.

1982-01-01

The thicker structural components are, the more important it is to take measures to reduce the volume of the weld. The welding process requiring the smallest possible weld section is the so-called narrow gap process. In submerged arc narrow gap welding as well as in MAG narrow gap welding different variants are imaginable, some of them already in practical use. With regard to efficiency and weld quality an optimum variant of the MAG narrow gap welding process is described. It constitutes a two wire system in which two wire electrodes of 1.2 mm diameter are arranged one behind the other. In order to avoid lack of fusion, the wire guides are slightly pointed towards each groove face. Thus, by inclining the two arcs burning one behind the other in the direction of weld progress, it is achieved that two separately solidifying weld pools and two beads per layer are simultaneously formed. Welding parameters are selected in such a way that a heat input of 16-20 kJ/cm and a deposition rate of 11-16 kgs/h are obtained. In spite of this comparatively high deposition rate, good impact values are found both in the weld and HAZ (largely reduced coarse-grain zone) which is due to an optimum weld build-up. With the available welding equipment the process can be applied to structural members having a thickness of 40-400 mm. The width of gap is 13 mm (root section) with a bevel angle of 1 0 . As filler metal, basic flux-cored wires are used which, depending on the base metal to be welded and the required tensile properties, can be of the Mn-, MnMo-, MnCrMo-, MnNi-, or MnNiMo-alloyed types. (orig.)

Advanced Welding Applications

Science.gov (United States)

Ding, Robert J.

2010-01-01

Some of the applications of advanced welding techniques are shown in this poster presentation. Included are brief explanations of the use on the Ares I and Ares V launch vehicle and on the Space Shuttle Launch vehicle. Also included are microstructural views from four advanced welding techniques: Variable Polarity Plasma Arc (VPPA) weld (fusion), self-reacting friction stir welding (SR-FSW), conventional FSW, and Tube Socket Weld (TSW) on aluminum.

Airborne nanoparticle exposures associated with the manual handling of nanoalumina and nanosilver in fume hoods

International Nuclear Information System (INIS)

Tsai, Su-Jung; Ada, Earl; Isaacs, Jacqueline A.; Ellenbecker, Michael J.

2009-01-01

Manual handling of nanoparticles is a fundamental task of most nanomaterial research; such handling may expose workers to ultrafine or nanoparticles. Recent studies confirm that exposures to ultrafine or nanoparticles produce adverse inflammatory responses in rodent lungs and such particles may translocate to other areas of the body, including the brain. An important method for protecting workers handling nanoparticles from exposure to airborne nanoparticles is the laboratory fume hood. Such hoods rely on the proper face velocity for optimum performance. In addition, several other hood design and operating factors can affect worker exposure. Handling experiments were performed to measure airborne particle concentration while handling nanoparticles in three fume hoods located in different buildings under a range of operating conditions. Nanoalumina and nanosilver were selected to perform handling experiments in the fume hoods. Air samples were also collected on polycarbonate membrane filters and particles were characterized by scanning electron microscopy. Handling tasks included transferring particles from beaker to beaker by spatula and by pouring. Measurement locations were the room background, the researcher's breathing zone and upstream and downstream from the handling location. Variable factors studied included hood design, transfer method, face velocity/sash location and material types. Airborne particle concentrations measured at breathing zone locations were analyzed to characterize exposure level. Statistics were used to test the correlation between data. The test results found that the handling of dry powders consisting of nano-sized particles inside laboratory fume hoods can result in a significant release of airborne nanoparticles from the fume hood into the laboratory environment and the researcher's breathing zone. Many variables were found to affect the extent of particle release including hood design, hood operation (sash height, face velocity

Airborne nanoparticle exposures associated with the manual handling of nanoalumina and nanosilver in fume hoods

Energy Technology Data Exchange (ETDEWEB)

Tsai, Su-Jung, E-mail: candace.umass@gmail.com; Ada, Earl [University of Massachusetts Lowell, NSF Center for High-rate Nanomanufacturing (CHN) (United States); Isaacs, Jacqueline A. [Northeastern University, NSF Center for High-rate Nanomanufacturing (CHN) (United States); Ellenbecker, Michael J. [University of Massachusetts Lowell, NSF Center for High-rate Nanomanufacturing (CHN) (United States)

2009-01-15

Manual handling of nanoparticles is a fundamental task of most nanomaterial research; such handling may expose workers to ultrafine or nanoparticles. Recent studies confirm that exposures to ultrafine or nanoparticles produce adverse inflammatory responses in rodent lungs and such particles may translocate to other areas of the body, including the brain. An important method for protecting workers handling nanoparticles from exposure to airborne nanoparticles is the laboratory fume hood. Such hoods rely on the proper face velocity for optimum performance. In addition, several other hood design and operating factors can affect worker exposure. Handling experiments were performed to measure airborne particle concentration while handling nanoparticles in three fume hoods located in different buildings under a range of operating conditions. Nanoalumina and nanosilver were selected to perform handling experiments in the fume hoods. Air samples were also collected on polycarbonate membrane filters and particles were characterized by scanning electron microscopy. Handling tasks included transferring particles from beaker to beaker by spatula and by pouring. Measurement locations were the room background, the researcher's breathing zone and upstream and downstream from the handling location. Variable factors studied included hood design, transfer method, face velocity/sash location and material types. Airborne particle concentrations measured at breathing zone locations were analyzed to characterize exposure level. Statistics were used to test the correlation between data. The test results found that the handling of dry powders consisting of nano-sized particles inside laboratory fume hoods can result in a significant release of airborne nanoparticles from the fume hood into the laboratory environment and the researcher's breathing zone. Many variables were found to affect the extent of particle release including hood design, hood operation (sash height, face

WELDING METHOD

Science.gov (United States)

Cornell, A.A.; Dunbar, J.V.; Ruffner, J.H.

1959-09-29

A semi-automatic method is described for the weld joining of pipes and fittings which utilizes the inert gasshielded consumable electrode electric arc welding technique, comprising laying down the root pass at a first peripheral velocity and thereafter laying down the filler passes over the root pass necessary to complete the weld by revolving the pipes and fittings at a second peripheral velocity different from the first peripheral velocity, maintaining the welding head in a fixed position as to the specific direction of revolution, while the longitudinal axis of the welding head is disposed angularly in the direction of revolution at amounts between twenty minutas and about four degrees from the first position.

Friction stir welding tool and process for welding dissimilar materials

Science.gov (United States)

Hovanski, Yuri; Grant, Glenn J; Jana, Saumyadeep; Mattlin, Karl F

2013-05-07

A friction stir welding tool and process for lap welding dissimilar materials are detailed. The invention includes a cutter scribe that penetrates and extrudes a first material of a lap weld stack to a preselected depth and further cuts a second material to provide a beneficial geometry defined by a plurality of mechanically interlocking features. The tool backfills the interlocking features generating a lap weld across the length of the interface between the dissimilar materials that enhances the shear strength of the lap weld.

Syllabus in Trade Welding.

Science.gov (United States)

New York State Education Dept., Albany. Bureau of Secondary Curriculum Development.

The syllabus outlines material for a course two academic years in length (minimum two and one-half hours daily experience) leading to entry-level occupational ability in several welding trade areas. Fourteen units covering are welding, gas welding, oxyacetylene welding, cutting, nonfusion processes, inert gas shielded-arc welding, welding cast…

Latest MIG, TIG arc-YAG laser hybrid welding systems for various welding products

Science.gov (United States)

Ishide, Takashi; Tsubota, Shuho; Watanabe, Masao

2003-03-01

Laser welding is capable of high-efficiency low-strain welding, and so its applications are started to various products. We have also put the high-power YAG laser of up to 10 kW to practical welding use for various products. On the other hand the weakest point of this laser welding is considered to be strict in the welding gap aiming allowance. In order to solve this problem, we have developed hybrid welding of TIG, MIG arc and YAG laser, taking the most advantages of both the laser and arc welding. Since the electrode is coaxial to the optical axis of the YAG laser in this process, it can be applied to welding of various objects. In the coaxial MIG, TIG-YAG welding, in order to make irradiation positions of the YAG laser beams having been guided in a wire or an electrode focused to the same position, the beam transmitted in fibers is separated to form a space between the separated beams, in which the laser is guided. With this method the beam-irradiating area can be brought near or to the arc-generating point. This enables welding of all directions even for the member of a three-dimensional shape. This time we carried out welding for various materials and have made their welding of up to 1 mm or more in welding groove gap possible. We have realized high-speed 1-pass butt welding of 4m/min in welding speed with the laser power of 3 kW for an aluminum alloy plate of approximately 4 mm thick. For a mild steel plate also we have realized butt welding of 1m/min with 5 kW for 6 mm thick. Further, in welding of stainless steel we have shown its welding possibility, by stabilizing the arc with the YAG laser in the welding atmosphere of pure argon, and shown that this welding is effective in high-efficiency welding of various materials. Here we will report the fundamental welding performances and applications to various objects for the coaxial MIG, TIG-YAG welding we have developed.

Ultrasonic testing of austenitic welds and its dependency on the welding process

International Nuclear Information System (INIS)

Tabatabaeipour, S.M.; Honarvar, F.

2009-01-01

This paper describes the ultrasonic testing of austenitic welds prepared by two different welding processes. The tests were carried out by the ultrasonic Time-of-Flight Diffraction (ToFD) technique. Shielded Metal Arc Welding (SMAW) and Gas Tungsten Arc Welding (GTAW) are the welding processes used for preparing the specimens. Identical artificial defects were implanted in both welds during the welding process. Both specimens were examined by the ToFD technique under similar conditions. Metallographic images were also obtained from the cross sectional plane of both the SMA and GTA welds. These images show that the grain orientation in the two welded specimens are different. D-scan images obtained by the ToFD technique from these welds indicates that inspecting the specimens prepared by the SMAW process is easier than the one made by the GTAW process. The results also show that the D-scan images cannot reveal the small vertical drilled holes implanted in the specimens. (author)

Friction Stir Welding of Tapered Thickness Welds Using an Adjustable Pin Tool

Science.gov (United States)

Adams, Glynn; Venable, Richard; Lawless, Kirby

2003-01-01

Friction stir welding (FSW) can be used for joining weld lands that vary in thickness along the length of the weld. An adjustable pin tool mechanism can be used to accomplish this in a single-pass, full-penetration weld by providing for precise changes in the pin length relative to the shoulder face during the weld process. The difficulty with this approach is in accurately adjusting the pin length to provide a consistent penetration ligament throughout the weld. The weld technique, control system, and instrumentation must account for mechanical and thermal compliances of the tooling system to conduct tapered welds successfully. In this study, a combination of static and in-situ measurements, as well as active control, is used to locate the pin accurately and maintain the desired penetration ligament. Frictional forces at the pin/shoulder interface were a source of error that affected accurate pin position. A traditional FSW pin tool design that requires a lead angle was used to join butt weld configurations that included both constant thickness and tapered sections. The pitch axis of the tooling was fixed throughout the weld; therefore, the effective lead angle in the tapered sections was restricted to within the tolerances allowed by the pin tool design. The sensitivity of the FSW process to factors such as thickness offset, joint gap, centerline offset, and taper transition offset were also studied. The joint gap and the thickness offset demonstrated the most adverse affects on the weld quality. Two separate tooling configurations were used to conduct tapered thickness welds successfully. The weld configurations included sections in which the thickness decreased along the weld, as well as sections in which the thickness increased along the weld. The data presented here include weld metallography, strength data, and process load data.

The technology and welding joint properties of hybrid laser-tig welding on thick plate

Science.gov (United States)

Shenghai, Zhang; Yifu, Shen; Huijuan, Qiu

2013-06-01

The technologies of autogenous laser welding and hybrid laser-TIG welding are used on thick plate of high strength lower alloy structural steel 10CrNiMnMoV in this article. The unique advantages of hybrid laser-TIG welding is summarized by comparing and analyzing the process parameters and welding joints of autogenous laser welding laser welding and hybrid laser-TIG welding. With the optimal process parameters of hybrid welding, the good welding joint without visible flaws can be obtained and its mechanical properties are tested according to industry standards. The results show that the hybrid welding technology has certain advantages and possibility in welding thick plates. It can reduce the demands of laser power, and it is significant for lowering the aspect ratio of weld during hybrid welding, so the gas in the molten pool can rise and escape easily while welding thick plates. Therefore, the pores forming tendency decreases. At the same time, hybrid welding enhances welding speed, and optimizes the energy input. The transition and grain size of the microstructure of hybrid welding joint is better and its hardness is higher than base material. Furthermore, its tensile strength and impact toughness is as good as base material. Consequently, the hybrid welding joint can meet the industry needs completely.

Effects of post weld heat treatment and weld overlay on the residual stress and mechanical properties in dissimilar metal weld

International Nuclear Information System (INIS)

Campos, Wagner R.C.; Ribeiro, Vladimir S.; Vilela, Alisson H.F.; Almeida, Camila R.O.; Rabello, Emerson G.

2017-01-01

The object of this work is a dissimilar metal weld (DMW) pipe joint between carbon steel (A-106 Gr B) and stainless steel (A-312 TP316L) pipes and filler metals of Nickel alloy (82/182), which find wide application in the field of chemical, oil, petroleum industries, fossil fuel and nuclear power plant. A lot of the failures that have occurred in dissimilar metal welded are affected greatly by residual stresses. Residual stress is often a cause of premature failure of critical components under normal operation of welded components. Several methods have been tested and developed for removing the tensile residual stresses. The aim of the methods is to reduce the tensile stress state or to create compressive stresses at a predefined area, such as the inner surface of a welded pipe joint. Post weld heat treatment (PWHT) and weld overlay (WOL) are two of the residual stress mitigation methods which reduce the tensile residual stress, create compressive stresses and arrest crack initiation and crack growth. The technique used to substantially minimized or eliminated this failure development in the root weld is the post weld heat treatments (stress relief heat treatment) or the weld overlay. In this work was studied the effectiveness in reducing internal residual stress in dissimilar metal welded pipe joints subjected to post weld heat treatment and weld overlay, measurement by hole-drilling strain-gage method of stress relaxation. Also held was mechanical characterization of the welded pipe joint itself. (author)

Effects of post weld heat treatment and weld overlay on the residual stress and mechanical properties in dissimilar metal weld

Energy Technology Data Exchange (ETDEWEB)

Campos, Wagner R.C.; Ribeiro, Vladimir S.; Vilela, Alisson H.F.; Almeida, Camila R.O.; Rabello, Emerson G., E-mail: wrcc@cdtn.br, E-mail: camilarezende.cr@gmail.com, E-mail: egr@cdtn.br, E-mail: vladimirsoler@hotmail.com, E-mail: ahfv02@outlook.com [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

2017-07-01

The object of this work is a dissimilar metal weld (DMW) pipe joint between carbon steel (A-106 Gr B) and stainless steel (A-312 TP316L) pipes and filler metals of Nickel alloy (82/182), which find wide application in the field of chemical, oil, petroleum industries, fossil fuel and nuclear power plant. A lot of the failures that have occurred in dissimilar metal welded are affected greatly by residual stresses. Residual stress is often a cause of premature failure of critical components under normal operation of welded components. Several methods have been tested and developed for removing the tensile residual stresses. The aim of the methods is to reduce the tensile stress state or to create compressive stresses at a predefined area, such as the inner surface of a welded pipe joint. Post weld heat treatment (PWHT) and weld overlay (WOL) are two of the residual stress mitigation methods which reduce the tensile residual stress, create compressive stresses and arrest crack initiation and crack growth. The technique used to substantially minimized or eliminated this failure development in the root weld is the post weld heat treatments (stress relief heat treatment) or the weld overlay. In this work was studied the effectiveness in reducing internal residual stress in dissimilar metal welded pipe joints subjected to post weld heat treatment and weld overlay, measurement by hole-drilling strain-gage method of stress relaxation. Also held was mechanical characterization of the welded pipe joint itself. (author)

On use of weld zone temperatures for online monitoring of weld quality in friction stir welding of naturally aged aluminium alloys

International Nuclear Information System (INIS)

Imam, Murshid; Biswas, Kajal; Racherla, Vikranth

2013-01-01

Highlights: • FSWs for 6063-T4 AA are done at different process parameters and sheet thicknesses. • Weld nugget zone and heat affected zone temperatures are monitored for each case. • Microstructural and mechanical characterisation of welds is done in all cases. • Weld ductility is found to be particularly sensitive to weld zone temperatures. • Strong correlation is found between WNZ and HAZ temperatures and weld properties. - Abstract: 6063-T4 aluminium alloy sheets of 3 and 6 mm thicknesses were friction stir butt welded using a square tool pin at a wide range of tool rotational speeds. Properties of obtained welds were characterised using tensile tests, optical micrographs, X-ray diffraction, and transmission electron microscopy. Shape, size, and distribution of precipitates in weld zones, and strength and ductility of welds were seen to directly correlate with peak temperatures in weld nugget and heat affected zones, independent of sheet thickness. In addition, fluctuations in measured temperature profiles, for 3 mm sheets, were seen to correlate with an increase in scatter of weld nugget zone properties for 3 mm sheets. Optimal weld strength and ductility were obtained for peak weld nugget zone temperatures of around 450 °C and corresponding peak heat affected zone temperatures of around 360–380 °C. Results obtained suggest that, at least for naturally aged aluminium alloys, nature of temperature evolution and magnitudes of peak temperatures in weld nugget and heat affected zones provide information on uniformity of properties in weld zones, overaging of heat affected zones, and formation of tunnel defects from improper material mixing at low weld zone temperatures

Measuring weld heat to evaluate weld integrity

Energy Technology Data Exchange (ETDEWEB)

Schauder, V., E-mail: schauder@hks-prozesstechnik.de [HKS-Prozesstechnik GmbH, Halle (Germany)

2015-11-15

Eddy current and ultrasonic testing are suitable for tube and pipe mills and have been used for weld seam flaw detection for decades, but a new process, thermography, is an alternative. By measuring the heat signature of the weld seam as it cools, it provides information about weld integrity at and below the surface. The thermal processes used to join metals, such as plasma, induction, laser, and gas tungsten arc welding (GTAW), have improved since they were developed, and they get better with each passing year. However, no industrial process is perfect, so companies that conduct research in flaw detection likewise continue to develop and improve the technologies used to verify weld integrity: ultrasonic testing (UT), eddy current testing (ET), hydrostatic, X-ray, magnetic particle, and liquid penetrant are among the most common. Two of these are used for verifying the integrity of the continuous welds such as those used on pipe and tube mills: UT and ET. Each uses a transmitter to send waves of ultrasonic energy or electrical current through the material and a receiver (probe) to detect disturbances in the flow. The two processes often are combined to capitalize on the strengths of each. While ET is good at detecting flaws at or near the surface, UT penetrates the material, detecting subsurface flaws. One drawback is that sound waves and electrical current waves have a specific direction of travel, or an alignment. A linear defect that runs parallel to the direction of travel of the ultrasonic sound wave or a flaw that is parallel to the coil winding direction of the ET probe can go undetected. A second drawback is that they don't detect cold welds. An alternative process, thermography, works in a different fashion: It monitors the heat of the material as the weld cools. Although it measures the heat at the surface, the heat signature provides clues about cooling activity deep in the material, resulting in a thorough assessment of the weld's integrity It

The effect of post-welding conditions in friction stir welds: From weld simulation to Ductile Failure

DEFF Research Database (Denmark)

Hattel, Jesper Henri; Nielsen, Kim Lau; Tutum, Cem Celal

2012-01-01

software ANSYS, a thermo-mechanical model is employed to predict the thermally induced stresses and strains during welding, while an in-house finite element code is used to study the plastic flow localization and failure in a subsequent structural analysis. The coupling between the two models is made......The post-welding stress state, strain history and material conditions of friction stir welded joints are often strongly idealized when used in subsequent modeling analyses, typically by neglecting one or more of the features above. But, it is obvious that the conditions after welding do influence......, showed the largest influence of the post-welding conditions, even though significant relaxation of the residual stress state was predicted....

Nitrogen And Oxygen Amount In Weld After Welding With Micro-Jet Cooling

Directory of Open Access Journals (Sweden)

Węgrzyn T.

2015-06-01

Full Text Available Micro-jet cooling after welding was tested only for MIG welding process with argon, helium and nitrogen as a shielded gases. A paper presents a piece of information about nitrogen and oxygen in weld after micro-jet cooling. There are put down information about gases that could be chosen both for MIG/MAG welding and for micro-jet process. There were given main information about influence of various micro-jet gases on metallographic structure of steel welds. Mechanical properties of weld was presented in terms of nitrogen and oxygen amount in WMD (weld metal deposit.

A study of weld quality in ultrasonic spot welding of similar and dissimilar metals

International Nuclear Information System (INIS)

Al-Sarraf, Z; Lucas, M

2012-01-01

Several difficulties are faced in joining thinner sheets of similar and dissimilar materials from fusion welding processes such as resistance welding and laser welding. Ultrasonic metal welding overcomes many of these difficulties by using high frequency vibration and applied pressure to create a solid-state weld. Ultrasonic metal welding is an effective technique in joining small components, such as in wire bonding, but is also capable of joining thicker sheet, depending on the control of welding conditions. This study presents the design, characterisation and test of a lateral-drive ultrasonic metal welding device. The ultrasonic welding horn is modelled using finite element analysis and its vibration behaviour is characterised experimentally to ensure ultrasonic energy is delivered to the weld coupon. The welding stack and fixtures are then designed and mounted on a test machine to allow a series of experiments to be conducted for various welding and ultrasonic parameters. Weld strength is subsequently analysed using tensile-shear tests. Control of the vibration amplitude profile through the weld cycle is used to enhance weld strength and quality, providing an opportunity to reduce part marking. Optical microscopic examination and scanning electron microscopy (SEM) were employed to investigate the weld quality. The results show how the weld quality is particularly sensitive to the combination of clamping force and vibration amplitude of the welding tip.

Welding and cutting

International Nuclear Information System (INIS)

Drews, P.; Schulze Frielinghaus, W.

1978-01-01

This is a survey, with 198 literature references, of the papers published in the fields of welding and cutting within the last three years. The subjects dealt with are: weldability of the materials - Welding methods - Thermal cutting - Shaping and calculation of welded joints - Environmental protection in welding and cutting. (orig.) [de

Exposure to respirable dust and manganese and prevalence of airways symptoms, among Swedish mild steel welders in the manufacturing industry.

Science.gov (United States)

Hedmer, Maria; Karlsson, Jan-Eric; Andersson, Ulla; Jacobsson, Helene; Nielsen, Jörn; Tinnerberg, Håkan

2014-08-01

Welding fume consists of metal fumes, e.g., manganese (Mn) and gases, e.g., ozone. Particles in the respirable dust (RD) size range dominate. Exposure to welding fume could cause short- and long-term respiratory effects. The prevalence of work-related symptoms among mild steel welders was studied, and the occupational exposure to welding fumes was quantified by repeated measurements of RD, respirable Mn, and ozone. Also the variance components were studied. A questionnaire concerning airway symptoms and occupational history was answered by 79% of a cohort of 484 welders. A group of welders (N = 108) were selected and surveyed by personal exposure measurements of RD and ozone three times during 1 year. The welders had a high frequency of work-related symptoms, e.g., stuffy nose (33%), ocular symptoms (28%), and dry cough (24%). The geometric mean exposure to RD and respirable Mn was 1.3 mg/m(3) (min-max 0.1-38.3 mg/m(3)) and 0.08 mg/m(3) (min-max <0.01-2.13 mg/m(3)), respectively. More than 50% of the Mn concentrations exceeded the Swedish occupational exposure limit (OEL). Mainly, low concentrations of ozone were measured, but 2% of the samples exceeded the OEL. Of the total variance for RD, 30 and 33% can be attributed to within-worker variability and between-company variability, respectively. Welders had a high prevalence of work-related symptom from the airways and eyes. The welders' exposure to Mn was unacceptably high. To reduce the exposure further, control measures in the welding workshops are needed. Correct use of general mechanical ventilation and local exhaust ventilation can, for example, efficiently reduce the exposure.

Simplified welding distortion analysis for fillet welding using composite shell elements

Directory of Open Access Journals (Sweden)

Mingyu Kim

2015-05-01

Full Text Available This paper presents the simplified welding distortion analysis method to predict the welding deformation of both plate and stiffener in fillet welds. Currently, the methods based on equivalent thermal strain like Strain as Direct Boundary (SDB has been widely used due to effective prediction of welding deformation. Regarding the fillet welding, however, those methods cannot represent deformation of both members at once since the temperature degree of freedom is shared at the intersection nodes in both members. In this paper, we propose new approach to simulate deformation of both members. The method can simulate fillet weld deformations by employing composite shell element and using different thermal expansion coefficients according to thickness direction with fixed temperature at intersection nodes. For verification purpose, we compare of result from experiments, 3D thermo elastic plastic analysis, SDB method and proposed method. Compared of experiments results, the proposed method can effectively predict welding deformation for fillet welds.

Welding Technician

Science.gov (United States)

Smith, Ken

2009-01-01

About 95% of all manufactured goods in this country are welded or joined in some way. These welded products range in nature from bicycle handlebars and skyscrapers to bridges and race cars. The author discusses what students need to know about careers for welding technicians--wages, responsibilities, skills needed, career advancement…

Effects of some anaesthetics on honeybees: nitrous oxide, carbon dioxide, ammonium nitrate smoker fumes

Energy Technology Data Exchange (ETDEWEB)

Simpson, J

1954-08-01

Honeybees were apparently unaffected by atmospheric oxygen concentrations between 7% and 100%, and only became motionless when the oxygen concentration was less than 2%. The effects of nitrous oxide-oxygen mixtures differed little, if at all, from those nitrogen-oxygen mixtures. Bees were not visibly affected by carbon dioxide concentrations up to 10-15% but they became motionless if the concentration exceeded 40-45%. Fumes produced by adding ammonium nitrate to the fuel in a beekeeper's smoker were found to contain hydrogen cyanide or cyanogen. Their effectiveness as an anaesthetic may be due to this or to some unidentified component, but not to nitrous oxide. All three anaesthetics caused foraging bees to stop collecting pollen, and accelerated the retrogression of the pharyngeal glands of young bees. Anaesthesia of a few bees in a colony with nitrous oxide, carbon dioxide, or ammonium nitrate smoker fumes did not appear to inhibit their drift back to the original site when their hive was moved, nor was any reduction in drifting observed when a whole colony was moved while anaesthetized with ammonium nitrate smoker fumes. 4 tables.

Introduction to Welding.

Science.gov (United States)

Fortney, Clarence; Gregory, Mike

This curriculum guide provides six units of instruction on basic welding. Addressed in the individual units of instruction are the following topics: employment opportunities for welders, welding safety and first aid, welding tools and equipment, basic metals and metallurgy, basic math and measuring, and procedures for applying for a welding job.…

Orbital welding technique

International Nuclear Information System (INIS)

Hoeschen, W.

2003-01-01

The TIG (Tungsten-inert gas) orbital welding technique is applied in all areas of pipe welding. The process is mainly used for austenitic and ferritic materials but also for materials like aluminium, nickel, and titanium alloys are commonly welded according to this technique. Thin-walled as well as thick-walled pipes are welded economically. The application of orbital welding is of particular interest in the area of maintenance of thick-walled pipes that is described in this article. (orig.) [de

Welding stresses

International Nuclear Information System (INIS)

Poirier, J.; Barbe, B.; Jolly, N.

1976-01-01

The aim is to show how internal stresses are generated and to fix the orders of magnitude. A realistic case, the vertical welding of thick plates free to move one against the other, is described and the deformations and stresses are analyzed. The mathematical model UEDA, which accounts for the elastic modulus, the yield strength and the expansion coefficient of the metal with temperature, is presented. The hypotheses and results given apply only to the instantaneous welding of a welded plate and to a plate welded by a moving electrode [fr

High-Speed Friction-Stir Welding to Enable Aluminum Tailor-Welded Blanks

Science.gov (United States)

Hovanski, Yuri; Upadhyay, Piyush; Carsley, John; Luzanski, Tom; Carlson, Blair; Eisenmenger, Mark; Soulami, Ayoub; Marshall, Dustin; Landino, Brandon; Hartfield-Wunsch, Susan

2015-05-01

Current welding technologies for production of aluminum tailor-welded blanks (TWBs) are utilized in low-volume and niche applications, and they have yet to be scaled for the high-volume vehicle market. This study targeted further weight reduction, part reduction, and cost savings by enabling tailor-welded blank technology for aluminum alloys at high volumes. While friction-stir welding (FSW) has been traditionally applied at linear velocities less than 1 m/min, high-volume production applications demand the process be extended to higher velocities more amenable to cost-sensitive production environments. Unfortunately, weld parameters and performance developed and characterized at low-to-moderate welding velocities do not directly translate to high-speed linear FSW. Therefore, to facilitate production of high-volume aluminum FSW components, parameters were developed with a minimum welding velocity of 3 m/min. With an emphasis on weld quality, welded blanks were evaluated for postweld formability using a combination of numerical and experimental methods. An evaluation across scales was ultimately validated by stamping full-size production door inner panels made from dissimilar thickness aluminum TWBs, which provided validation of the numerical and experimental analysis of laboratory-scale tests.

Estimation of weld nugget temperature by thermography method in resistance projection welding process

International Nuclear Information System (INIS)

Setty, D.S.; Rameswara Roa, A.; Hemantha Rao, G.V.S.; Jaya Raj, R.N.

2008-01-01

In the Pressurized Heavy Water Reactor (PHWR) fuel manufacturing, zirconium alloy appendages like spacer and bearing pads are welded to the thin wall zirconium alloy fuel tubes by using resistance projection welding process. Out of many joining processes available, resistance-welding process is reliable, environment friendly and best suitable for mass production applications. In the fuel assembly, spacer pads are used to get the required inter-element spacing and Bearing pads are used to get the required load-bearing surface for the fuel assembly. Performance of the fuel assembly in the reactor is greatly influenced by these weld joint's quality. Phase transformation from α to β phase is not acceptable while welding these tiny appendages. At present only destructive metallography test is available for this purpose. This can also be achieved by measuring weld nugget temperature where in the phase transformation temperature for zirconium alloy material is 853 o C. The temperature distribution during resistance welding of tiny parts cannot be measured by conventional methods due to very small space and short weld times involved in the process. Shear strength, dimensional accuracy and weld microstructures are some of the key parameters used to measure the quality of appendage weld joints. Weld parameters were optimized with the help of industrial experimentation methodology. Individual projection welding by split electrode concept, and during welding on empty tube firm support is achieved on inner side of the tube by using expandable pneumatic mandrel. In the present paper, an attempt was made to measure the weld nugget temperature by thermography technique and is correlated with standard microstructures of zirconium alloy material. The temperature profiles in the welding process are presented for different welding conditions. This technique has helped in measuring the weld nugget temperature more accurately. It was observed that in the present appendage welding

Influence of Loading Direction and Weld Reinforcement on Fatigue Performance of TIG Weld Seam

Directory of Open Access Journals (Sweden)

HUI Li

2018-02-01

Full Text Available The influence of loading direction and weld reinforcement on fatigue performance of TC2 titanium alloy TIG weld seam was investigated via fatigue experiments and SEM fracture observation. The results show that the fatigue life of retaining weld reinforcement specimens is lower than that of removing one in the same weld direction. The fatigue life of oblique weld specimens is higher than that of straight one with the same weld reinforcement treatment. The initiation of removing weld reinforcement specimens' fatigue crack sources is in the hole defect, but the weld reinforcement specimen initiate at the weld toes. During the early stage of fatigue crack propagation, the cracks all grow inside the weld seam metal with obvious fatigue striation. And the fatigue cracks of oblique weld specimens pass through the weld seam into the base with a typical toughness fatigue striation during the last stage of fatigue crack propagation. The dimple of straight weld specimens is little and shallow in the final fracture zone. The oblique weld specimens broke in the base metal area, and the dimple is dense.

Nitrogen And Oxygen Amount In Weld After Welding With Micro-Jet Cooling

OpenAIRE

Węgrzyn T.; Piwnik J.

2015-01-01

Micro-jet cooling after welding was tested only for MIG welding process with argon, helium and nitrogen as a shielded gases. A paper presents a piece of information about nitrogen and oxygen in weld after micro-jet cooling. There are put down information about gases that could be chosen both for MIG/MAG welding and for micro-jet process. There were given main information about influence of various micro-jet gases on metallographic structure of steel welds. Mechanical properties of weld was pr...

Influence of silica fume on the strength of high strength concrete

International Nuclear Information System (INIS)

Akram, T.; Memon, S.A.; Khan, S.A.

2007-01-01

HSC (High Strength Concrete) does not become evident by a sudden change in the behavior of 'ordinary strength' concrete. There is a gradual effect that becomes more noticeable when the strength level exceeds about 40-45 MPa. There cannot be a precise level of strength which defines this change in effect. The effects are on strength and workability, requiring us to take into account in our mix proportioning, the ramifications of fineness of cement on workability and of type of aggregate and aggregate/cement ratio on strength. In fact, the selection of materials becomes more critical as the concrete strength increases and that if very high strength is required (100 MPa and higher), relatively few materials may be suitable. An experimental investigation is carried out to evaluate the feasibility of producing HSC using locally available materials and to study the influence of silica fume on the strength of HSC. The main variables in this research is amount of silica fume. The parameters that are kept constant are the amount of cement equal to 580 kg/m3, dosage of HRWRA (High Range Water Reducing Admictures) equal to 4 % by weight of cementitious materials and the ratio of fine aggregate to coarse aggregate (1:2.3). Test results revealed that it is feasible to produce HSC using locally available materials. The optimum percentage of silica fume was found to be 15 % by weight of cement. (author)

Effect of silica fume on the characterization of the geopolymer materials

Science.gov (United States)

Khater, Hisham M.

2013-12-01

The influence of silica fume (SF) addition on properties of geopolymer materials produced from alkaline activation of alumino-silicates metakaolin and waste concrete produced from demolition works has been studied through the measurement of compressive strength, Fourier transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy (SEM) analysis. Alumino-silicate materials are coarse aggregate included waste concrete and fired kaolin (metakaolin) at 800°C for 3 h, both passing a sieve of 90 μm. Mix specimens containing silica fume were prepared at water/binder ratios in a range of 0.30 under water curing. The used activators are an equal mix of sodium hydroxide and silicate in the ratio of 3:3 wt.%. The control geopolymer mix is composed of metakaolin and waste concrete in an equal mix (50:50, wt.%). Waste concrete was partially replaced by silica fume by 1 to 10 wt.%. The results indicated that compressive strengths of geopolymer mixes incorporating SF increased up to 7% substitution and then decreased up to 10% but still higher than that of the control mix. Results indicated that compressive strengths of geopolymer mixes incorporating SF increases up to 7% substitution and then decreases up to 10% but still higher than the control mix, where 7% SF-digested calcium hydroxide (CH) crystals, decreased the orientation of CH crystals, reduced the crystal size of CH gathered at the interface, and improved the interface more effectively.

Influence of weld structure on cross-weld creep behavior in P23 steel

Energy Technology Data Exchange (ETDEWEB)

Allen, D.J.; Degnan, C.C. [E.ON Engineering (United Kingdom); Brett, S.J. [RWE npower (United Kingdom); Buchanan, L.W. [Doosan Babcock (United Kingdom)

2010-07-01

A thick section pipe weld in low alloy steel P23 has been characterised by cross-weld creep rupture testing at a range of stresses, together with all-weld-metal and parent material testing, under the auspices of the UK High Temperature Power Plant Forum. The results generally show that the weld metal can be weak when tested in the transverse (cross-weld) orientation, and can fail with limited overall ductility by cracking in the zone of refined weld metal beneath the fusion boundary of the superposed weld bead. However, one specimen showed a much superior performance, which could be understood in terms of its locally more creep resistant weld macrostructure. The implications for P23 performance and weld manufacture are discussed. (orig.)

Welded joints integrity analysis and optimization for fiber laser welding of dissimilar materials

Science.gov (United States)

Ai, Yuewei; Shao, Xinyu; Jiang, Ping; Li, Peigen; Liu, Yang; Liu, Wei

2016-11-01

Dissimilar materials welded joints provide many advantages in power, automotive, chemical, and spacecraft industries. The weld bead integrity which is determined by process parameters plays a significant role in the welding quality during the fiber laser welding (FLW) of dissimilar materials. In this paper, an optimization method by taking the integrity of the weld bead and weld area into consideration is proposed for FLW of dissimilar materials, the low carbon steel and stainless steel. The relationships between the weld bead integrity and process parameters are developed by the genetic algorithm optimized back propagation neural network (GA-BPNN). The particle swarm optimization (PSO) algorithm is taken for optimizing the predicted outputs from GA-BPNN for the objective. Through the optimization process, the desired weld bead with good integrity and minimum weld area are obtained and the corresponding microstructure and microhardness are excellent. The mechanical properties of the optimized joints are greatly improved compared with that of the un-optimized welded joints. Moreover, the effects of significant factors are analyzed based on the statistical approach and the laser power (LP) is identified as the most significant factor on the weld bead integrity and weld area. The results indicate that the proposed method is effective for improving the reliability and stability of welded joints in the practical production.

Increased levels of oxidative DNA damage attributable to cooking-oil fumes exposure among cooks.

Science.gov (United States)

Ke, Yuebin; Cheng, Jinquan; Zhang, Zhicheng; Zhang, Renli; Zhang, Zhunzhen; Shuai, Zhihong; Wu, Tangchun

2009-07-01

Previous investigations have indicated that cooks are exposed to polycyclic aromatic hydrocarbons (PAHs) from cooking-oil fumes. However, Emission of PAH and their carcinogenic potencies from cooking oil fumes sources have not been investigated among cooks. To investigate the urinary excretion of a marker for oxidative DNA damage, 8-hydroxydeoxyguanosine (8-OHdG), in different groups of cooks and different exposure groups, and to study the association between 8-OHdG and 1-hydroxypyrene(1-OHP), a biological marker for PAH exposure. Urine samples were collected from different groups of cooks (n = 86) and from unexposed controls (n = 36); all were male with similar age and smoking habits. The health status, occupational history, smoking, and alcohol consumption 24 h prior to sampling was estimated from questionnaires. The urine samples were frozen for later analyses of 8-OHdG and 1-OHP levels by high-performance liquid chromatography. Excretion in urine of 8-OHdG was similar for controls (mean 1.2micromol/mol creatinine, n = 36), and for those who had been in the kitchen with an exhaust-hood operating (mean 1.5micromol/mol creatinine, n = 45). Cooks exposed to cooking-oil fumes without exhaust-hood operation had significantly increased excretion of 8-OHdG (mean 2.3micromol/mol creatinine, n = 18), compared with controls. The urinary levels of ln 1-OHP and ln 8-OHdG were still significantly correlated in a multiple regression analysis. The results indicate that exposure to PAH or possibly other compounds in cooking-oil fumes may cause oxidative DNA damage.

Ciclesonide Oral Inhalation

Science.gov (United States)

... use ciclesonide inhalation.Ciclesonide inhalation helps to prevent asthma attacks (sudden episodes of shortness of breath, wheezing, and coughing) but will not stop an asthma attack that has already started. Do not use ciclesonide ...

Flunisolide Oral Inhalation

Science.gov (United States)

... use flunisolide inhalation.Flunisolide inhalation helps to prevent asthma attacks (sudden episodes of shortness of breath, wheezing, and coughing) but will not stop an asthma attack that has already started. Do not use flunisolide ...

Laser Welding Test Results with Gas Atmospheres in Welding Chamber

Energy Technology Data Exchange (ETDEWEB)

Joung, Chang-Young; Hong, Jin-Tae; Ahn, Sung-Ho; Heo, Sung-Ho; Jang, Seo-Yun; Yang, Tae-Ho [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2015-10-15

The weld beads of specimens welded under identical conditions in the helium and argon gas were cleaner, more regular, and steadier than those in a vacuum. The penetration depth of the FZ in the vacuum was much deeper than those in the helium and argon gas. To measure the irradiation properties of nuclear fuel in a test reactor, a nuclear fuel test rod instrumented with various sensors must be fabricated with assembly processes. A laser welding system to assemble the nuclear fuel test rod was designed and fabricated to develop various welding technologies of the fuel test rods to joint between a cladding tube and end-caps. It is an air-cooling optical fiber type and its emission modes are a continuous (CW) mode of which the laser generates continuous emission, and pulse (QCW) mode in which the laser internally generates sequences of pulses. We considered the system welding a sample in a chamber that can weld a specimen in a vacuum and inert gas atmosphere, and the chamber was installed on the working plate of the laser welding system. In the chamber, the laser welding process should be conducted to have no defects on the sealing area between a cladding tube and an end-cap.

Effect of plasticizer and fumed silica on ionic conductivity behaviour

Indian Academy of Sciences (India)

The effect of addition of propylene carbonate (PC) and nano-sized fumed silica on the ionic conductivity behaviour of proton conducting polymer electrolytes containing different concentrations of hexafluorophosphoric acid (HPF6) in polyethylene oxide (PEO) has been studied. The addition of PC results in an increase in ...

Welding of Thin Steel Plates by Hybrid Welding Process Combined TIG Arc with YAG Laser

Science.gov (United States)

Kim, Taewon; Suga, Yasuo; Koike, Takashi

TIG arc welding and laser welding are used widely in the world. However, these welding processes have some advantages and problems respectively. In order to improve problems and make use of advantages of the arc welding and the laser welding processes, hybrid welding process combined the TIG arc with the YAG laser was studied. Especially, the suitable welding conditions for thin steel plate welding were investigated to obtain sound weld with beautiful surface and back beads but without weld defects. As a result, it was confirmed that the shot position of the laser beam is very important to obtain sound welds in hybrid welding. Therefore, a new intelligent system to monitor the welding area using vision sensor is constructed. Furthermore, control system to shot the laser beam to a selected position in molten pool, which is formed by TIG arc, is constructed. As a result of welding experiments using these systems, it is confirmed that the hybrid welding process and the control system are effective on the stable welding of thin stainless steel plates.

Study on properties of mortar using silica fume and ground blast furnace slag. Silica fume oyobi koro slag funmatsu wo mochiita mortar no tokusei ni kansuru kenkyu

Energy Technology Data Exchange (ETDEWEB)

Shiiba, H; Honda, S; Araki, A [Fukuoka University, Fukuoka (Japan). Faculty of Engineering

1992-09-01

The effect of silica fume and ground blast furnace slag in concrete on the content of superplasticizer, and dynamic properties of hardened mortar with such admixtures were studied experimentally. Although the dependence of a flow value on the superplasticizer was dominated by kinds of superplasticizers, blast furnace slag enhanced the flow value resulting in a high fluidity. Adsorption of superplasticizers onto admixtures was dependent on kinds of superplasticizers, and adsorption onto blast furnace slag was 1.3-2 times that onto normal Portland cement (NPC). The compressive strength of mortar increased by mixing admixtures, while the bending strength was enhanced only by mixing silica fume. Mixing mortar was lower in dynamic elastic modulus than NPC mortar at the same compressive strength, and the velocity of supersonic wave in mortar was scarcely affected by mixing. 11 refs., 14 figs., 3 tabs.

Hybrid laser-arc welding

DEFF Research Database (Denmark)

Hybrid laser-arc welding (HLAW) is a combination of laser welding with arc welding that overcomes many of the shortfalls of both processes. This important book gives a comprehensive account of hybrid laser-arc welding technology and applications. The first part of the book reviews...... the characteristics of the process, including the properties of joints produced by hybrid laser-arc welding and ways of assessing weld quality. Part II discusses applications of the process to such metals as magnesium alloys, aluminium and steel as well as the use of hybrid laser-arc welding in such sectors as ship...... building and the automotive industry. With its distinguished editor and international team of contributors, Hybrid laser-arc welding, will be a valuable source of reference for all those using this important welding technology. Professor Flemming Ove Olsen works in the Department of Manufacturing...

Plug-welding of ODS cladding tube for BOR-60 irradiation. Welding condition setting. Device remodeling and welding

International Nuclear Information System (INIS)

Seki, Masayuki; Ishibashi, Fujio; Kono, Syusaku; Hirako, Kazuhito; Tsukada, Tatsuya

2003-04-01

Irradiation test in BOR-60 at RIAR to judge practical use prospect of ODS cladding tube at early stage is planned as Japan-Russia a joint research. RIAR does fuel design of fuel pin used for this joint research. JNC manufactures ODS cladding tube and bar materials (two steel kind of martensite and ferrite), upper endplug production. They are welded by pressurized resistance welding, and are inspected in JNC Tokai, transported to RIAR. And RIAR manufactures vibration packing fuel pin. On the upper endplug welding by pressurized resistance welding method, we worded on the problems such as decision of welding condition by changing the size and crystallization of cladding tube and the design of endplug, and the chucking device remodeling to correspond to the long scale cladding tube welding system (included handling) and of quality assurance method. Especially, use of long scale cladding tube caused problem that bending transformation occurred in cladding tube by welding pressure. However, we solved this problem by shortening the distance of cladding tube colette chuck and pressure receiving, and by putting the sleeve in an internal space of welding machine, losing the bending of cladding tube. Moreover, welding defects were occurred by the difference of an inside state, an inside defect and recrystallization of cladding tube. We solved the problem by inside grinding for the edge of tube, angle beam method by ultrasonic wave, and ultrasonic wave form confirmation. Manufacturing process with long scale cladding tube including heat-treatment to remove combustion return and remaining stress was established besides, Afterwards, welding of ODS cladding tube and upper endplug. As the quality assurance system, we constructed [Documented procedure (referred to JOYO)] based on [Document of the QA plan] by OEC. Welding and inspection were executed by the document procedure. It is thought that the quality assurance method become references for the irradiation test in JOYO in the

Weld analysis and control system

Science.gov (United States)

Kennedy, Larry Z. (Inventor); Rodgers, Michael H. (Inventor); Powell, Bradley W. (Inventor); Burroughs, Ivan A. (Inventor); Goode, K. Wayne (Inventor)

1994-01-01

The invention is a Weld Analysis and Control System developed for active weld system control through real time weld data acquisition. Closed-loop control is based on analysis of weld system parameters and weld geometry. The system is adapted for use with automated welding apparatus having a weld controller which is capable of active electronic control of all aspects of a welding operation. Enhanced graphics and data displays are provided for post-weld analysis. The system provides parameter acquisition, including seam location which is acquired for active torch cross-seam positioning. Torch stand-off is also monitored for control. Weld bead and parent surface geometrical parameters are acquired as an indication of weld quality. These parameters include mismatch, peaking, undercut, underfill, crown height, weld width, puddle diameter, and other measurable information about the weld puddle regions, such as puddle symmetry, etc. These parameters provide a basis for active control as well as post-weld quality analysis and verification. Weld system parameters, such as voltage, current and wire feed rate, are also monitored and archived for correlation with quality parameters.

The Effect of Aging and Silanization on the Mechanical Properties of Fumed Silica-based Dental Composite

Directory of Open Access Journals (Sweden)

Khaje S

2015-12-01

Full Text Available Statement of Problem: Mechanical strength and durability of dental composites are the main topics studied in this field of science today. This study examined fumed silica-based composite as a strong and durable restorative material through flexural and cycling test methods. Objectives: The purpose of this study was to evaluate the effect of silanization, ageing, cycling and hybridizing on mechanical properties of fumed silica-based resin composite. Materials and Methods: Composites were made of light-cured copolymer based on Bisphenol A glycolmethacrylate (Bis-GMA and Triethylene glycoldimethacrylate (TEGDMA at proportion of 50:50 which reinforced by fumed silica filler. For each composite sample, 5 specimen bars were made using Teflon mould (2 x 2 x 25 mm3. The samples with 12 wt% fumed silica (FS were considered as a base line group. The samples were exposed to cyclic cold water (FS-CCW and hot water (FS-CHW. The effect of silanization and adding more filler was studied together with samples containing 12 wt% (FS-S (12, 16 wt% (FS-S (16 and 20 wt% (FS-S (20 fumed silica filler. The filler was silanized with (γ-MPS. The degree of conversion was assessed with Fourier Transform Infra-Red spectroscopy. Flexural properties were evaluated with the Three-Point Bending test. Flexural data were analyzed with Excel software. Hardness was measured with an Atomic Force Microscope (AFM. Results: The degree of conversion of the resin reached 74% within 24 hrs. Salinization allowed more filler to be wetted by resin. Addition of silanized particles from sample FS-S (12 to sample FS-S (20 improved the mechanical strength. Hybridizing fumed silica with nano-silica (FS-N had no significant effect on the strength, but nano-hardness improved greatly. Ageing and cycling had adverse effects on the strength of the sample FS. The flexural strength of FS-CHW was 72% less than FS sample. Conclusions: Sample FS-N with low diluent and filler percentage complied with the

Fine tuning of dwelling time in friction stir welding for preventing material overheating, weld tensile strength increase and weld nugget size decrease

Directory of Open Access Journals (Sweden)

Mijajlović Miroslav M.

2016-01-01

Full Text Available After successful welding, destructive testing into test samples from Al 2024-T351 friction stir butt welds showed that tensile strength of the weld improve along the joint line, while dimensions of the weld nugget decrease. For those welds, both the base material and the welding tool constantly cool down during the welding phase. Obviously, the base material became overheated during the long dwelling phase what made conditions for creation of joints with the reduced mechanical properties. Preserving all process parameters but varying the dwelling time from 5-27 seconds a new set of welding is done to reach maximal achievable tensile strength. An analytical-numerical-experimental model is used for optimising the duration of the dwelling time while searching for the maximal tensile strength of the welds

Blunted behavioral and c Fos responses to acidic fumes in the African naked mole-rat.

Science.gov (United States)

LaVinka, Pamela Colleen; Park, Thomas J

2012-01-01

Acidosis in the skin triggers activation of pain pathways and behaviors indicative of pain in vertebrates. The exception is the naked mole-rat, the only known vertebrate to show physiological and behavioral insensitivity to acid pain in the skin. The goal of the present study was to determine behavioral and physiological responses of this species to airborne acidic fumes, which would be expected to affect the trigeminal pain pathway in other species. Behaviorally, naked mole-rats did not avoid fumes from moderately high concentrations of acetic acid (10 and 20%), and c Fos labeling showed no increase in activity in the trigeminal nuclei and nucleus tractus solitarius. In contrast, these concentrations triggered behavioral aversion and increased Fos activity in other laboratory rodents. For a very high concentration of acetic acid (50%), naked mole-rats showed significant avoidance behavior and increased Fos labeling in the nucleus tractus solitarius caudal region, which receives vagal chemosensory information. However, there was no increase in trigeminal labeling, and in fact, activity significantly decreased. This pattern is opposite of that associated with another irritant, ammonia fumes, which elicited an increase in trigeminal but not nucleus tractus solitarius Fos labeling, and no behavioral avoidance. Behavioral avoidance of acidic fumes, but no increased labeling in the trigeminal pain nucleus is consistent with the notion of adaptations to blunt acid pain, which would be advantageous for naked mole-rats as they normally live under chronically high levels of acidosis-inducing CO(2).

Blunted behavioral and c Fos responses to acidic fumes in the African naked mole-rat.

Directory of Open Access Journals (Sweden)

Pamela Colleen LaVinka

Full Text Available Acidosis in the skin triggers activation of pain pathways and behaviors indicative of pain in vertebrates. The exception is the naked mole-rat, the only known vertebrate to show physiological and behavioral insensitivity to acid pain in the skin. The goal of the present study was to determine behavioral and physiological responses of this species to airborne acidic fumes, which would be expected to affect the trigeminal pain pathway in other species. Behaviorally, naked mole-rats did not avoid fumes from moderately high concentrations of acetic acid (10 and 20%, and c Fos labeling showed no increase in activity in the trigeminal nuclei and nucleus tractus solitarius. In contrast, these concentrations triggered behavioral aversion and increased Fos activity in other laboratory rodents. For a very high concentration of acetic acid (50%, naked mole-rats showed significant avoidance behavior and increased Fos labeling in the nucleus tractus solitarius caudal region, which receives vagal chemosensory information. However, there was no increase in trigeminal labeling, and in fact, activity significantly decreased. This pattern is opposite of that associated with another irritant, ammonia fumes, which elicited an increase in trigeminal but not nucleus tractus solitarius Fos labeling, and no behavioral avoidance. Behavioral avoidance of acidic fumes, but no increased labeling in the trigeminal pain nucleus is consistent with the notion of adaptations to blunt acid pain, which would be advantageous for naked mole-rats as they normally live under chronically high levels of acidosis-inducing CO(2.

A new method for infrared imaging of air currents in and around critical hazard fume hoods

International Nuclear Information System (INIS)

Mulac, W.A.; McCreary, J.R.; Schmalz, H.

1992-01-01

A real time method of measuring and recording the efficacy of vapor containment in and around critical hazard fume hoods is being developed. An infrared camera whose response is restricted to a spectral range that overlaps a strong absorption band in a non-toxic gas is used to render real-time video images of the presence and flow of the gas. The gas, nitrous oxide, is ejected in a continuous stream in and around fume hoods that are to be certified capable of containing hazardous fumes. The principle advantage is that various scenarios of air flow displacement in and outside the hood can be easily investigated; the principle limitation is the necessity of high tracer gas concentration to obtain strong visualizations. We hope that this technique can be found to be an effective and safe method to test hoods in locations that were built before present regulations were promulgated

Optimum welding condition of 2017 aluminum similar alloy friction welded joints

Energy Technology Data Exchange (ETDEWEB)

Tsujino R.; Ochi, H. [Osaka Inst. of Tech., Osaka (Japan); Morikawa, K. [Osaka Sangyo Univ., Osaka (Japan); Yamaguchi, H.; Ogawa, K. [Osaka Prefecture Univ., Osaka (Japan); Fujishiro, Y.; Yoshida, M. [Sumitomo Metal Technology Ltd., Hyogo (Japan)

2002-07-01

Usefulness of the statistical analysis for judging optimization of the friction welding conditions was investigated by using 2017 aluminum similar alloy, where many samples under fixed welding conditions were friction welded and analyzed statistically. In general, selection of the optimum friction welding conditions for similar materials is easy. However, it was not always the case for 2017 aluminum alloy. For optimum friction welding conditions of this material, it is necessary to apply relatively larger upset pressure to obtain high friction heating. Joint efficiencies obtained under the optimum friction welding conditions showed large shape parameter (m value) of Weibull distribution as well as in the dissimilar materials previously reported. The m value calculated on the small number of data can be substituted for m value on the 30 data. Therefore, m value is useful for practical use in the factory for assuming the propriety of the friction welding conditions. (orig.)

Dual wire welding torch and method

Science.gov (United States)

Diez, Fernando Martinez; Stump, Kevin S.; Ludewig, Howard W.; Kilty, Alan L.; Robinson, Matthew M.; Egland, Keith M.

2009-04-28

A welding torch includes a nozzle with a first welding wire guide configured to orient a first welding wire in a first welding wire orientation, and a second welding wire guide configured to orient a second welding wire in a second welding wire orientation that is non-coplanar and divergent with respect to the first welding wire orientation. A method of welding includes moving a welding torch with respect to a workpiece joint to be welded. During moving the welding torch, a first welding wire is fed through a first welding wire guide defining a first welding wire orientation and a second welding wire is fed through a second welding wire guide defining a second welding wire orientation that is divergent and non-coplanar with respect to the first welding wire orientation.

TIG welding method and TIG welding device

International Nuclear Information System (INIS)

Yoneda, Eishi

1998-01-01

The present invention provides a method of TIG welding for members having different heat capacities including a cladding tube and an end plug of a fuel rod to be used, for example, in a reactor, and a device therefor. Namely, in the TIG welding method, the flow rate of a sealed gas to the side of a member having smaller heat capacity is made greater than that on the side of the member having greater heat capacity bordered on the top end of a welding electrode. Since the sealed gas is jetted being localized relative to the welding electrode, arc is restricted in a region of the member having smaller heat capacity and is increased at a region having a larger heat capacity. As a result, the arc is localized, so that the heat input amount to the region having a large heat capacity is increased, and then a plurality of members at the abutting portion are melted uniformly thereby capable of obtaining a uniform molten pool. A bead is formed at the abutting portion thereby capable of obtaining a welded portion with less unevenness and having large strength. (I.S.)

Experimental investigation on the weld pool formation process in plasma keyhole arc welding

Science.gov (United States)

Van Anh, Nguyen; Tashiro, Shinichi; Van Hanh, Bui; Tanaka, Manabu

2018-01-01

This paper seeks to clarify the weld pool formation process in plasma keyhole arc welding (PKAW). We adopted, for the first time, the measurement of the 3D convection inside the weld pool in PKAW by stereo synchronous imaging of tungsten tracer particles using two sets of x-ray transmission systems. The 2D convection on the weld pool surface was also measured using zirconia tracer particles. Through these measurements, the convection in a wide range of weld pools from the vicinity of the keyhole to the rear region was successfully visualized. In order to discuss the heat transport process in a weld pool, the 2D temperature distribution on the weld pool surface was also measured by two-color pyrometry. The results of the comprehensive experimental measurement indicate that the shear force due to plasma flow is found to be the dominant driving force in the weld pool formation process in PKAW. Thus, heat transport in a weld pool is considered to be governed by two large convective patterns near the keyhole: (1) eddy pairs on the surface (perpendicular to the torch axis), and (2) eddy pairs on the bulk of the weld pool (on the plane of the torch). They are formed with an equal velocity of approximately 0.35 m s-1 and are mainly driven by shear force. Furthermore, the flow velocity of the weld pool convection becomes considerably higher than that of other welding processes, such as TIG welding and GMA welding, due to larger plasma flow velocity.

Problem of industrial fumes in the forested valleys of Savoy

Energy Technology Data Exchange (ETDEWEB)

Bossavy, J

1962-01-01

A study of injury to forest trees in the Maurienne valley, caused by F in the fumes from aluminum factories was made. Of the local conifers, Pinus sylvestris was the most susceptible, followed by Picea abies and Abies alba; Larch has so far proved resistant, as have broadleaved deciduous species.

Automatization of welding

International Nuclear Information System (INIS)

Iwabuchi, Masashi; Tomita, Jinji; Nishihara, Katsunori.

1978-01-01

Automatization of welding is one of the effective measures for securing high degree of quality of nuclear power equipment, as well as for correspondence to the environment at the site of plant. As the latest ones of the automatic welders practically used for welding of nuclear power apparatuses in factories of Toshiba and IHI, those for pipes and lining tanks are described here. The pipe welder performs the battering welding on the inside of pipe end as the so-called IGSCC countermeasure and the succeeding butt welding through the same controller. The lining tank welder is able to perform simultaneous welding of two parallel weld lines on a large thin plate lining tank. Both types of the welders are demonstrating excellent performance at the shops as well as at the plant site. (author)

Electric arc welding gun

Science.gov (United States)

Luttrell, Edward; Turner, Paul W.

1978-01-01

This invention relates to improved apparatus for arc welding an interior joint formed by intersecting tubular members. As an example, the invention is well suited for applications where many similar small-diameter vertical lines are to be welded to a long horizontal header. The improved apparatus includes an arc welding gun having a specially designed welding head which is not only very compact but also produces welds that are essentially free from rolled-over solidified metal. The welding head consists of the upper end of the barrel and a reversely extending electrode holder, or tip, which defines an acute angle with the barrel. As used in the above-mentioned example, the gun is positioned to extend upwardly through the vertical member and the joint to be welded, with its welding head disposed within the horizontal header. Depending on the design of the welding head, the barrel then is either rotated or revolved about the axis of the vertical member to cause the electrode to track the joint.

A novel weld seam detection method for space weld seam of narrow butt joint in laser welding

Science.gov (United States)

Shao, Wen Jun; Huang, Yu; Zhang, Yong

2018-02-01

Structured light measurement is widely used for weld seam detection owing to its high measurement precision and robust. However, there is nearly no geometrical deformation of the stripe projected onto weld face, whose seam width is less than 0.1 mm and without misalignment. So, it's very difficult to ensure an exact retrieval of the seam feature. This issue is raised as laser welding for butt joint of thin metal plate is widely applied. Moreover, measurement for the seam width, seam center and the normal vector of the weld face at the same time during welding process is of great importance to the welding quality but rarely reported. Consequently, a seam measurement method based on vision sensor for space weld seam of narrow butt joint is proposed in this article. Three laser stripes with different wave length are project on the weldment, in which two red laser stripes are designed and used to measure the three dimensional profile of the weld face by the principle of optical triangulation, and the third green laser stripe is used as light source to measure the edge and the centerline of the seam by the principle of passive vision sensor. The corresponding image process algorithm is proposed to extract the centerline of the red laser stripes as well as the seam feature. All these three laser stripes are captured and processed in a single image so that the three dimensional position of the space weld seam can be obtained simultaneously. Finally, the result of experiment reveals that the proposed method can meet the precision demand of space narrow butt joint.

Investigation into Variations of Welding Residual Stresses and Redistribution Behaviors for Different Repair Welding Widths

International Nuclear Information System (INIS)

Park, Chiyong; Lee, Hweesueng; Huh, Namsu

2014-01-01

In this study, we investigated the variations in welding residual stresses in dissimilar metal butt weld due to width of repair welding and re-distribution behaviors resulting from similar metal welding (SMW) and mechanical loading. To this end, detailed two-dimensional axi-symmetric finite element (FE) analyses were performed considering five different repair welding widths. Based on the FE results, we first evaluated the welding residual stress distributions in repair welding. We then investigated the re-distribution behaviors of the residual stresses due to SMW and mechanical loads. It is revealed that large tensile welding residual stresses take place in the inner surface and that its distribution is affected, provided repair welding width is larger than certain value. The welding residual stresses resulting from repair welding are remarkably reduced due to SMW and mechanical loading, regardless of the width of the repair welding

Certification of a weld produced by friction stir welding

Science.gov (United States)

Obaditch, Chris; Grant, Glenn J

2013-10-01

Methods, devices, and systems for providing certification of friction stir welds are disclosed. A sensor is used to collect information related to a friction stir weld. Data from the sensor is compared to threshold values provided by an extrinsic standard setting organizations using a certification engine. The certification engine subsequently produces a report on the certification status of the weld.

Laser beam welding and friction stir welding of 6013-T6 aluminium alloy sheet

International Nuclear Information System (INIS)

Braun, R.; Dalle Donne, C.; Staniek, G.

2000-01-01

Butt welds of 1.6 mm thick 6013-T6 sheet were produced using laser beam welding and friction stir welding processes. Employing the former joining technique, filler powders of the alloys Al-5%Mg and Al-12%Si were used. Microstructure, hardness profiles, tensile properties and the corrosion behaviour of the welds in the as-welded condition were investigated. The hardness in the weld zone was lower compared to that of the base material in the peak-aged temper. Hardness minima were measured in the fusion zone and in the thermomechanically affected zone for laser beam welded and friction stir welded joints, respectively. Metallographic and fractographic examinations revealed pores in the fusion zone of the laser beam welds. Porosity was higher in welds made using the filler alloy Al-5%Mg than using the filler metal Al-12%Si. Transmission electron microscopy indicated that the β '' (Mg 2 Si) hardening precipitates were dissolved in the weld zone due to the heat input of the joining processes. Joint efficiencies achieved for laser beam welds depended upon the filler powders, being about 60 and 80% using the alloys Al-5%Mg and Al-12%Si, respectively. Strength of the friction stir weld approached over 80% of the ultimate tensile strength of the 6013-T6 base material. Fracture occurred in the region of hardness minima unless defects in the weld zone led to premature failure. The heat input during welding did not cause a degradation of the corrosion behaviour of the welds, as found in continuous immersion tests in an aqueous chloride-peroxide solution. In contrast to the 6013-T6 parent material, the weld zone was not sensitive to intergranular corrosion. Alternate immersion tests in 3.5% NaCl solution indicated high stress corrosion cracking resistance of the joints. For laser beam welded sheet, the weld zone of alternately immersed specimens suffered severe degradation by pitting and intergranular corrosion, which may be associated with galvanic coupling of filler metal and

Process for quality assurance of welded joints for electrical resistance point welding

International Nuclear Information System (INIS)

Schaefer, R.; Singh, S.

1977-01-01

In order to guarantee the reproducibility of welded joints of even quality (above all in the metal working industry), it is proposed that before starting resistance point welding, a preheating current should be allowed to flow at the site of the weld. A given reduction of the total resistance at the site of the weld should effect the time when the preheating current is switched over to welding current. This value is always predetermined empirically. Further possibilities of controlling the welding process are described, where the measurement of thermal expansion of the parts is used. A standard welding time is given. The rated course of electrode movement during the process can be predicted and a running comparison of nominal and actual values can be carried out. (RW) [de

Weld nugget formation in resistance spot welding of new lightweight sandwich material

DEFF Research Database (Denmark)

Sagüés Tanco, J.; Nielsen, Chris Valentin; Chergui, Azeddine

2015-01-01

Weldability of a new lightweight sandwich material, LITECOR®, by resistance spot welding is analyzed by experiments and numerical simulations. The spot welding process is accommodated by a first pulse squeezing out the non-conductive polymer core of the sandwich material locally to allow metal......–metal contact. This is facilitated by the use of a shunt tool and is followed by a second pulse for the actual spot welding and nugget formation. A weldability lobe in the time-current space of the second pulse reveals a process window of acceptable size for automotive assembly lines. Weld growth curves...... with experimental results in the range of welding parameters leading to acceptable weld nugget sizes. The validated accuracy of the commercially available software proves the tool useful for assisting the choice of welding parameters....

Residual stress by repair welds

International Nuclear Information System (INIS)

Mochizuki, Masahito; Toyoda, Masao

2003-01-01

Residual stress by repair welds is computed using the thermal elastic-plastic analysis with phase-transformation effect. Coupling phenomena of temperature, microstructure, and stress-strain fields are simulated in the finite-element analysis. Weld bond of a plate butt-welded joint is gouged and then deposited by weld metal in repair process. Heat source is synchronously moved with the deposition of the finite-element as the weld deposition. Microstructure is considered by using CCT diagram and the transformation behavior in the repair weld is also simulated. The effects of initial stress, heat input, and weld length on residual stress distribution are studied from the organic results of numerical analysis. Initial residual stress before repair weld has no influence on the residual stress after repair treatment near weld metal, because the initial stress near weld metal releases due to high temperature of repair weld and then stress by repair weld regenerates. Heat input has an effect for residual stress distribution, for not its magnitude but distribution zone. Weld length should be considered reducing the magnitude of residual stress in the edge of weld bead; short bead induces high tensile residual stress. (author)

Handbook of Plastic Welding

DEFF Research Database (Denmark)

Islam, Aminul

The purpose of this document is to summarize the information about the laser welding of plastic. Laser welding is a matured process nevertheless laser welding of micro dimensional plastic parts is still a big challenge. This report collects the latest information about the laser welding of plastic...... materials and provides an extensive knowhow on the industrial plastic welding process. The objectives of the report include: - Provide the general knowhow of laser welding for the beginners - Summarize the state-of-the-art information on the laser welding of plastics - Find the technological limits in terms...... of design, materials and process - Find the best technology, process and machines adaptive to Sonion’s components - Provide the skills to Sonion’s Design Engineers for successful design of the of the plastic components suitable for the laser welding The ultimate goal of this report is to serve...

Boosting Active Contours for Weld Pool Visual Tracking in Automatic Arc Welding

DEFF Research Database (Denmark)

Liu, Jinchao; Fan, Zhun; Olsen, Søren Ingvor

2015-01-01

Detecting the shape of the non-rigid molten metal during welding, so-called weld pool visual sensing, is one of the central tasks for automating arc welding processes. It is challenging due to the strong interference of the high-intensity arc light and spatters as well as the lack of robust...... approaches to detect and represent the shape of the nonrigid weld pool. We propose a solution using active contours including an prior for the weld pool boundary composition. Also, we apply Adaboost to select a small set of features that captures the relevant information. The proposed method is applied...... to weld pool tracking and the presented results verified its feasibility....

Analysis of welding distortion due to narrow-gap welding of upper port plug

International Nuclear Information System (INIS)

Biswas, Pankaj; Mandal, N.R.; Vasu, Parameswaran; Padasalag, Shrishail B.

2010-01-01

Narrow-gap welding is a low distortion welding process. This process allows very thick plates to be joined using fewer weld passes as compared to conventional V-groove or double V-groove welding. In case of narrow-gap arc welding as the heat input and weld volume is low, it reduces thermal stress leading to reduction of both residual stress and distortion. In this present study the effect of narrow-gap welding was studied on fabrication of a scaled down port plug in the form of a trapezoidal box made of 10 mm thick mild steel (MS) plates using gas tungsten arc welding (GTAW). Inherent strain method was used for numerical prediction of resulting distortions. The numerical results compared well with that of the experimentally measured distortion. The validated numerical scheme was used for prediction of weld induced distortion due to narrow-gap welding of full scale upper port plug made of 60 mm thick SS316LN material as is proposed for use in ITER project. It was observed that it is feasible to fabricate the said port plug keeping the distortions minimum within about 7 mm using GTAW for root pass welding followed by SMAW for filler runs.

Welding processes handbook

CERN Document Server

Weman, Klas

2003-01-01

Deals with the main commercially significant and commonly used welding processes. This title takes the student or novice welder through the individual steps involved in each process in an easily understood way. It covers many of the requirements referred to in European Standards including EN719, EN 729, EN 729 and EN 287.$bWelding processes handbook is a concise, explanatory guide to the main commercially significant and commonly-used welding processes. It takes the novice welder or student through the individual steps involved in each process in a clear and easily understood way. It is intended to provide an up-to-date reference to the major applications of welding as they are used in industry. The contents have been arranged so that it can be used as a textbook for European welding courses in accordance with guidelines from the European Welding Federation. Welding processes and equipment necessary for each process are described so that they can be applied to all instruction levels required by the EWF and th...

Comparative study on strength properties of cement mortar by partial replacement of cement with ceramic powder and silica fume

Science.gov (United States)

Himabindu, Ch.; Geethasri, Ch.; Hari, N.

2018-05-01

Cement mortar is a mixture of cement and sand. Usage of high amount of cement increases the consumption of natural resources and electric power. To overcome this problem we need to replace cement with some other material. Cement is replaced with many other materials like ceramic powder, silica fume, fly ash, granulated blast furnace slag, metakaolin etc.. In this research cement is replaced with ceramic powder and silica fume. Different combinations of ceramic powder and silica fume in cement were replaced. Cement mortar cubes of 1:3 grade were prepared. These cubes were cured under normal water for 7 days, 14days and 28 days. Compressive strength test was conducted for all mixes of cement mortar cubes.

Ultrasonic Stir Welding

Science.gov (United States)

Nabors, Sammy

2015-01-01

NASA Marshall Space Flight Center (MSFC) developed Ultrasonic Stir Welding (USW) to join large pieces of very high-strength metals such as titanium and Inconel. USW, a solid-state weld process, improves current thermal stir welding processes by adding high-power ultrasonic (HPU) energy at 20 kHz frequency. The addition of ultrasonic energy significantly reduces axial, frictional, and shear forces; increases travel rates; and reduces wear on the stir rod, which results in extended stir rod life. The USW process decouples the heating, stirring, and forging elements found in the friction stir welding process allowing for independent control of each process element and, ultimately, greater process control and repeatability. Because of the independent control of USW process elements, closed-loop temperature control can be integrated into the system so that a constant weld nugget temperature can be maintained during welding.

Inhalant allergies in children.

Science.gov (United States)

Mims, James W; Veling, Maria C

2011-06-01

Children with chronic or recurrent upper respiratory inflammatory disease (rhinitis) should be considered for inhalant allergies. Risk factors for inhalant allergies in children include a first-degree relative with allergies, food allergy in infancy, and atopic dermatitis. Although inhalant allergies are rare in infancy, inhalant allergies are common in older children and impair quality of life and productivity. Differentiating between viral and allergic rhinitis can be challenging in children, but the child's age, history, and risk factors can provide helpful information. Allergic rhinitis is a risk factor for asthma, and if one is present, medical consideration of the other is warranted. Copyright © 2011 Elsevier Inc. All rights reserved.

Inhalant Abuse and Dextromethorphan.

Science.gov (United States)

Storck, Michael; Black, Laura; Liddell, Morgan

2016-07-01

Inhalant abuse is the intentional inhalation of a volatile substance for the purpose of achieving an altered mental state. As an important, yet underrecognized form of substance abuse, inhalant abuse crosses all demographic, ethnic, and socioeconomic boundaries, causing significant morbidity and mortality in school-aged and older children. This review presents current perspectives on epidemiology, detection, and clinical challenges of inhalant abuse and offers advice regarding the medical and mental health providers' roles in the prevention and management of this substance abuse problem. Also discussed is the misuse of a specific "over-the-counter" dissociative, dextromethorphan. Copyright © 2016 Elsevier Inc. All rights reserved.

The effects of welded joint characteristics on its properties in HDPE thermal fusion welding

Science.gov (United States)

Dai, Hongbin; Peng, Jun

2017-05-01

In this paper, PE100 pipes with the diameter of 200 mm and the thickness of 11.9 mm were used as material. The welded joints were obtained in different welding pressures with the optimal welding temperature of 220∘C. Reheating process on the welded joints with the temperature of 130∘C was carried out. The joints exhibited X-type, and the cause of X-type joints was discussed. The temperature field in the forming process of welded joints was measured, and tensile and bending tests on welded joints were carried out. The fracture surface of welded joints was observed by scanning electron microscopy (SEM), and crystallinity calculation was taken by X-ray diffraction (XRD). The mechanism of X-type weld profile effects on welded joints properties was analyzed. It was concluded that the mechanical properties of welded joints decrease with the reduced X distance between lines.

Inhaled Drug Delivery: A Practical Guide to Prescribing Inhaler Devices

Directory of Open Access Journals (Sweden)

Pierre Ernst

1998-01-01

Full Text Available Direct delivery of medication to the target organ results in a high ratio of local to systemic bioavailability and has made aerosol delivery of respiratory medication the route of choice for the treatment of obstructive lung diseases. The most commonly prescribed device is the pressurized metered dose inhaler (pMDI; its major drawback is the requirement that inspiration and actuation of the device be well coordinated. Other requirements for effective drug delivery include an optimal inspiratory flow, a full inspiration from functional residual capacity and a breath hold of at least 6 s. Available pMDIs are to be gradually phased out due to their use of atmospheric ozone-depleting chlorofluorocarbons (CFCs as propellants. Newer pMDI devices using non-CFC propellants are available; preliminary experience suggests these devices greatly increase systemic bioavailability of inhaled corticosteroids. The newer multidose dry powder inhalation devices (DPIs are breath actuated, thus facilitating coordination with inspiration, and contain fewer ingredients. Furthermore, drug delivery is adequate even at low inspired flows, making their use appropriate in almost all situations. Equivalence of dosing among different devices for inhaled corticosteroids will remain imprecise, requiring the physician to adjust the dose of medication to the lowest dose that provides adequate control of asthma. Asthma education will be needed to instruct patients on the effective use of the numerous inhalation devices available.

Autogenous Deformation and Change of the Relative Humidity in Silica Fume-Modified Cement Paste

DEFF Research Database (Denmark)

Jensen, Ole mejlhede; Hansen, Per Freiesleben

1996-01-01

Even during sealed curing and at a constant temperature a hardening cement paste will deform and the relative humidity within its pores will lower. This autogenous deformation and autogenous relative humidity change may be so significant that the cement paste cracks if the deformation is restrained....... This article focuses on the influence of silica fume addition on autogenous deformation and autogenous relative humidity change. Continuous measurement of autogenous deformation and autogenous relative humidity change for more than 1 year and 1« years, respectively, was performed. The investigations show...... thatsilica fume addition markedly increases the autogenous shrinkage as well as the autogenous relative humidity change....

Recent advances in the TIG welding process and the application of the welding of nuclear components

International Nuclear Information System (INIS)

Lucas, W.; Males, B.O.

1982-01-01

Recent advances in the field of precision arc welding techniques and infacilities for production of nuclear power plant components arc presented. Of the precision welding techniques, pulsed TIG welding, pulsed plasma arc welding, hot-wire TIG welding, and pulsed inert-gas metal-arc welding. In the field of weld cladding, GMA plasma welding is cited as an alternative to submerged-arc welding with a strip electrode. Transistors and computer-controlled welding systems get a special mention. Applications of TIG welding in the UK are cited, e.g. welding of components for the AGR nuclear power plant and construction of equipment for repair work in feedwater pipes of the MAGNOX reactor. (orig.) [de

WELDING TORCH

Science.gov (United States)

Correy, T.B.

1961-10-01

A welding torch into which water and inert gas are piped separately for cooling and for providing a suitable gaseous atmosphere is described. A welding electrode is clamped in the torch by a removable collet sleeve and a removable collet head. Replacement of the sleeve and head with larger or smaller sleeve and head permits a larger or smaller welding electrode to be substituted on the torch. (AEC)

Welding procedure specification for arc welding of St 52-3N steel plates with covered electrodes

International Nuclear Information System (INIS)

Cvetkovski, S.; Slavkov, D.; Magdeski, J.

2003-01-01

In this paper the results of approval welding technology for arc welding of plates made of St 52-3N steel are presented. Metal arc welding with covered electrode is used welding process. Test specimens are butt welded in different welding positions P A , P F , P C and P D . Before start welding preliminary welding procedure was prepared. After welding of test specimens non destructive and destructive testing was performed. Obtained results were compared with standard DIN 17100 which concerns to chemical composition and mechanical properties of base material. It was confirmed that in all cases mechanical properties of welded joint are higher than those of base material, so preliminary welding procedure (pWTS) can be accepted as welding procedure specification WPS for metal arc welding of St52-3N steel. (Original)

Variant selection of martensites in steel welded joints with low transformation temperature weld metals

International Nuclear Information System (INIS)

Takahashi, Masaru; Yasuda, Hiroyuki Y.

2013-01-01

Highlights: ► We examined the variant selection of martensites in the weld metals. ► We also measured the residual stress developed in the butt and box welded joints. ► 24 martensite variants were randomly selected in the butt welded joint. ► High tensile residual stress in the box welded joint led to the strong variant selection. ► We discussed the rule of the variant selection focusing on the residual stress. -- Abstract: Martensitic transformation behavior in steel welded joints with low transformation temperature weld (LTTW) metal was examined focusing on the variant selection of martensites. The butt and box welded joints were prepared with LTTW metals and 980 MPa grade high strength steels. The residual stress of the welded joints, which was measured by a neutron diffraction technique, was effectively reduced by the expansion of the LTTW metals by the martensitic transformation during cooling after the welding process. In the LTTW metals, the retained austenite and martensite phases have the Kurdjumov–Sachs (K–S) orientation relationship. The variant selection of the martensites in the LTTW metals depended strongly on the type of welded joints. In the butt welded joint, 24 K–S variants were almost randomly selected while a few variants were preferentially chosen in the box welded joint. This suggests that the high residual stress developed in the box welded joint accelerated the formation of specific variants during the cooling process, in contrast to the butt welded joint with low residual stress

Corrosion resistance of «tube – tubesheet» weld joint obtained by friction welding

Directory of Open Access Journals (Sweden)

RIZVANOV Rif Garifovich

2017-08-01

Full Text Available Shell-and-tube heat exchangers are widely applied for implementation of various processes at ventures of fuel and energy complex. Cost of production and reliability of heat exchangers of this type is to a wide extent determined by corresponding characteristics of tube bundle, «tube – tubesheet» is its typical joint in particular when welding operations are used in order to attach tubes to tubesheet in addition to expansion. When manufacturing such equipment of heat-resistant chrome-bearing or chromium-molybdenum steels including steel 15H5M, the process of fixed joint manufacturing gets significantly more complicated and costly due to the necessity to use thermal treatment before, during and after welding (this problem is particularly applicable for manufacturing of large-size equipment. One of the options to exclude thermal treatment from manufacturing process is to use «non-arc» welding methods – laser welding, explosion welding as well as friction welding. Use of each of the welding methods mentioned above during production of heat-exchange equipment has its process challenges and peculiarities. This article gives a comparative analysis of weld structure and distribution of electrode potentials of welded joints and parent metal of the joints simulating welding of tube to tubesheet of steel 15H5M using the following welding methods: shielded manual arc welding, tungsten-arc inert-gas welding and friction welding. Comparative analysis of macro- and microstructures of specific zones of the studied welded joints showed that the joints produced by arc welding methods do not exhibit evident inhomogeneity of the structure after application of thermal treatment which is explained by the correctness of thermal treatment. Joints obtained via friction welding are characterized by structural inhomogeneity of the welded joint zone metal microstructure. The ultra-fine-grained structure obtained as a result of friction welding makes it possible to

The Effect of Weld Reinforcement and Post-Welding Cooling Cycles on Fatigue Strength of Butt-Welded Joints under Cyclic Tensile Loading.

Science.gov (United States)

Araque, Oscar; Arzola, Nelson; Hernández, Edgar

2018-04-12

This research deals with the fatigue behavior of butt-welded joints, by considering the geometry and post-welding cooling cycles, as a result of cooling in quiet air and immersed in water. ASTM A-36 HR structural steel was used as the base metal for the shielded metal arc welding (SMAW) process with welding electrode E6013. The welding reinforcement was 1 mm and 3 mm, respectively; axial fatigue tests were carried out to determine the life and behavior in cracks propagation of the tested welded joints, mechanical characterization tests of properties in welded joints such as microhardness, Charpy impact test and metallographic analysis were carried out. The latter were used as input for the analysis by finite elements which influence the initiation and propagation of cracks and the evaluation of stress intensity factors (SIF). The latter led to obtaining the crack propagation rate and the geometric factor. The tested specimens were analyzed, by taking photographs of the cracks at its beginning in order to make a count of the marks at the origin of the crack. From the results obtained and the marks count, the fatigue crack growth rate and the influence of the cooling media on the life of the welded joint are validated, according to the experimental results. It can be concluded that the welded joints with a higher weld reinforcement have a shorter fatigue life. This is due to the stress concentration that occurs in the vicinity of the weld toe.

Distortion Control during Welding

NARCIS (Netherlands)

Akbari Pazooki, A.M.

2014-01-01

The local material expansion and contraction involved in welding result in permanent deformations or instability i.e., welding distortion. Considerable efforts have been made in controlling welding distortion prior to, during or after welding. Thermal Tensioning (TT) describes a group of in-situ

Arc-weld pool interactions

International Nuclear Information System (INIS)

Glickstein, S.S.

1978-08-01

The mechanisms involved in arc-weld pool interactions are extremely complex and no complete theory is presently available to describe much of the phenomena observed during welding. For the past several years, experimental and analytical studies have been undertaken at the Bettis Atomic Power Laboratory to increase basic understanding of the gas tungsten arc welding process. These studies have included experimental spectral analysis of the arc in order to determine arc temperature and analytical modeling of the arc and weld puddle. The investigations have been directed toward determining the cause and effects of variations in the energy distribution incident upon the weldment. In addition, the effect of weld puddle distortion on weld penetration was investigated, and experimental and analytical studies of weld process variables have been undertaken to determine the effects of the variables upon weld penetration and configuration. A review of the results and analysis of these studies are presented

Welding electrode for peripheral welds of A-1 reactor pressure vessel

International Nuclear Information System (INIS)

Lakatos, L.

1975-01-01

The properties are outlined of the VUZ-AC1-52 welding electrode used in welding the Bohunice A-1 reactor pressure vessel. The mechanical properties of welded joints after the final thermal treatment are summed up. (J.K.)

Quantification of Microtexture at Weld Nugget of Friction Stir-Welded Carbon Steel

Science.gov (United States)

Husain, Md M.; Sarkar, R.; Pal, T. K.; Ghosh, M.; Prabhu, N.

2017-05-01

Friction stir welding of C-Mn steel was carried out under 800-1400 rpm tool rotation. Tool traversing speed of 50 mm/min remained same for all joints. Effect of thermal state and deformation on texture and microstructure at weld nugget was investigated. Weld nugget consisted of ferrite + bainite/Widmanstatten ferrite with different matrix grain sizes depending on peak temperature. A texture around ( ϕ 2 = 0°, φ = 30°, ϕ 2 = 45°) was developed at weld nugget. Grain boundary misorientation at weld nugget indicated that continuous dynamic recrystallization influenced the development of fine equiaxed grain structure. Pole figures and orientation distribution function were used to determine crystallographic texture at weld nugget and base metal. Shear texture components D1, D2 and F were present at weld nugget. D1 shear texture was more prominent among all. Large number of high-angle grain boundaries ( 60-70%) was observed at weld nugget and was the resultant of accumulation of high amount of dislocation, followed by subgrain formation.

Nickel-base alloy overlay weld with improved ultrasonic flaw detection by magnetic stirring welding

International Nuclear Information System (INIS)

Takashi, Hirano; Kenji, Hirano; Masayuki, Watando; Takahiro, Arakawa; Minoru, Maeda

2001-01-01

Ultrasonic flaw detection is more difficult in Nickel-base alloy welds containing dendrites owing to the decrease ultrasonic transmissibility they cause. The present paper discusses application of magnetic stirring welding as a means for reducing dendrite growth with consequent improvement in ultrasonic transmissibility. Single pass and multi-pass welding tests were conducted to determine optimal welding conditions. By PT and macro observation subsequent to welding was carried out, optimal operation conditions were clarified. Overlay welding tests and UT clearly indicated ultrasonic beam transmissibility in overlay welds to be improved and detection capacity to be greater through application of magnetic stirring welding. Optimal operation conditions were determined based on examination of temper bead effects in the heat affected zone of low alloy steel by application of magnetic stirring welding to the butt welded joints between low alloy and stainless steel. Hardness in this zone of low alloy steel after the fourth layer was less than 350 HV. (author)

Effect of weld spacing on microstructure and mechanical properties of CLAM electron beam welding joints

Energy Technology Data Exchange (ETDEWEB)

Zhai, Yutao; Huang, Bo, E-mail: aufa0007@163.com; Zhang, Junyu; Zhang, Baoren; Liu, Shaojun; Huang, Qunying

2016-11-15

Highlights: • The welded joints of CLAM steel with different weld spacings have been fabricated with electron beam welding, and a simplified model of CLAM sheet was proposed. • The microstructure and mechanical properties such as microhardness, impact and tensile were investigated at different welding spacing for both conditions of as-welded and post weld heat treatment (PWHT). • The effect of the welding thermal cycle was significantly when the weld spacings were smaller than 4 mm. • When the weld spacing was small enough, the original microstructures would be fragmented with the high heat input. - Abstract: China low activation martensitic (CLAM) steel has been chosen as the primary structural material in the designs of dual function lithium-lead (DFLL) blanket for fusion reactors, China helium cooled ceramic breeder (HCCB) test blanket module (TBM) for ITER and China fusion engineering test reactor (CFETR) blanket. The cooling components of the blankets are designed with high density cooling channels (HDCCs) to remove the high nuclear thermal effectively. Hence, the welding spacing among the channels are small. In this paper, the welded joints of CLAM steel with different weld spacings have been fabricated with electron beam welding (EBW). The weld spacing was designed to be 2 mm, 3 mm, 4 mm, 6 mm and 8 mm. The microstructure and mechanical properties such as microhardness, impact and tensile were investigated at different welding spacing for both conditions of as-welded and post weld heat treatment (PWHT). The PWHT is tempering at 740 °C for 120 min. The results showed that the grain size in the heat affected zone (HAZ) increased with the increasing weld spacing, and the joint with small weld spacing had a better performance after PWHT. This work would give useful guidance to improve the preparation of the cooling components of blanket.

Capabilities of infrared weld monitor

Energy Technology Data Exchange (ETDEWEB)

Sanders, P.G.; Keske, J.S.; Leong, K.H.; Kornecki, G.

1997-11-01

A non-obtrusive pre-aligned, solid-state device has been developed to monitor the primary infrared emissions during laser welding. The weld monitor output is a 100-1000 mV signal that depends on the beam power and weld characteristics. The DC level of this signal is related to weld penetration, while AC portions of the output can be correlated with surface irregularities and part misalignment or contamination. Changes in DC behavior are also noted for both full and deep penetration welds. Full penetration welds are signified by an abrupt reduction in the weld monitor output. Bead on plate welds were made on steel, aluminum, and magnesium with both a CW CO{sub 2} laser and a pulsed Nd:YAG laser to explore the relationships between the weld characteristics and the weld monitor output.

Welding overlay analysis of dissimilar metal weld cracking of feedwater nozzle

International Nuclear Information System (INIS)

Tsai, Y.L.; Wang, Li. H.; Fan, T.W.; Ranganath, Sam; Wang, C.K.; Chou, C.P.

2010-01-01

Inspection of the weld between the feedwater nozzle and the safe end at one Taiwan BWR showed axial indications in the Alloy 182 weld. The indication was sufficiently deep that continued operation could not be justified considering the crack growth for one cycle. A weld overlay was decided to implement for restoring the structural margin. This study reviews the cracking cases of feedwater nozzle welds in other nuclear plants, and reports the lesson learned in the engineering project of this weld overlay repair. The overlay design, the FCG calculation and the stress analysis by FEM are presented to confirm that the Code Case structural margins are met. The evaluations of the effect of weld shrinkage on the attached feedwater piping are also included. A number of challenges encountered in the engineering and analysis period are proposed for future study.

Effect of paint fumes on histoarchitecture of the testes of adult male ...

African Journals Online (AJOL)

abdominal incision was performed after which one testis was received from each rats, preserved in 10% formal saline and further processed for histological study using Hematoxylin and eosin technique. Results: The testes of the paint fumes ...

Multi-physics modeling and numerical simulation of weld pool in GTA welding

International Nuclear Information System (INIS)

Nguyen, Minh-Chien

2015-01-01

In this work, we develop a 3D physical and numerical model of the GTA (Gas Tungsten Arc) welding process in order to predict, for given welding parameters, useful quantities for the designer of welded assembly: weld bead shape, fluid flow in the weld pool as well as thermal distribution in the work piece. The model is developed in the Cast3M (http://www-cast3m.cea.fr/) finite element software and takes into account the main physical phenomena acting in the work piece and particularly in the weld pool, subject to source terms modeling the arc part of the welding process. A steady solution of this model is thought for and involves the coupling of the nonlinear thermohydraulics and electromagnetic equations together with the displacement of the deformable free surface of the weld pool. A first step in the development consisted in modeling the electromagnetic phenomena with two different numerical methods, in comparing the numerical results obtained with those of the literature and in quantifying the importance of the Lorentz force and the Joule effect compared to the other mechanical and thermal sources by computing power balances. Then, in order to assess the predictive capability of the model, simulations of various welding configurations are performed: variation in the chemical composition of the material, of the welding speed, of the prescribed arc pressure and of the welding positions, which is a focus of this work, are studied. A good agreement is obtained between the results of our model and other experimental and numerical results of the literature. Eventually, a model accounting for metal filling is proposed and its results are discussed. Thus, our complete model can be seen as a solid foundation towards future totally-coupled 3D welding models including the arc and it will be included in WPROCESS the in-house CEA software dedicated to the numerical simulation of welding. (author) [fr

Effect of Silica Fume on two-stage Concrete Strength

Science.gov (United States)

Abdelgader, H. S.; El-Baden, A. S.

2015-11-01

Two-stage concrete (TSC) is an innovative concrete that does not require vibration for placing and compaction. TSC is a simple concept; it is made using the same basic constituents as traditional concrete: cement, coarse aggregate, sand and water as well as mineral and chemical admixtures. As its name suggests, it is produced through a two-stage process. Firstly washed coarse aggregate is placed into the formwork in-situ. Later a specifically designed self compacting grout is introduced into the form from the lowest point under gravity pressure to fill the voids, cementing the aggregate into a monolith. The hardened concrete is dense, homogeneous and has in general improved engineering properties and durability. This paper presents the results from a research work attempt to study the effect of silica fume (SF) and superplasticizers admixtures (SP) on compressive and tensile strength of TSC using various combinations of water to cement ratio (w/c) and cement to sand ratio (c/s). Thirty six concrete mixes with different grout constituents were tested. From each mix twenty four standard cylinder samples of size (150mm×300mm) of concrete containing crushed aggregate were produced. The tested samples were made from combinations of w/c equal to: 0.45, 0.55 and 0.85, and three c/s of values: 0.5, 1 and 1.5. Silica fume was added at a dosage of 6% of weight of cement, while superplasticizer was added at a dosage of 2% of cement weight. Results indicated that both tensile and compressive strength of TSC can be statistically derived as a function of w/c and c/s with good correlation coefficients. The basic principle of traditional concrete, which says that an increase in water/cement ratio will lead to a reduction in compressive strength, was shown to hold true for TSC specimens tested. Using a combination of both silica fume and superplasticisers caused a significant increase in strength relative to control mixes.

Detecting flaws in welds

International Nuclear Information System (INIS)

Woodacre, A.; Lawton, H.

1979-01-01

An apparatus and a method for detecting flaws in welds in a workpiece, the portion of the workpiece containing the weld is maintained at a constant temperature and the weld is scanned by an infra red detector. The weld is then scanned again with the workpiece in contact with a cooling probe to produce a steeper temperature gradient across the weld. Comparison of the signals produced by each scan reveals the existence of defects in the welds. The signals may be displayed on an oscilloscope and the display may be observed by a TV camera and recorded on videotape. (UK)

Evaluation of a novel educational strategy, including inhaler-based reminder labels, to improve asthma inhaler technique.

Science.gov (United States)

Basheti, Iman A; Armour, Carol L; Bosnic-Anticevich, Sinthia Z; Reddel, Helen K

2008-07-01

To evaluate the feasibility, acceptability and effectiveness of a brief intervention about inhaler technique, delivered by community pharmacists to asthma patients. Thirty-one pharmacists received brief workshop education (Active: n=16, CONTROL: n=15). Active Group pharmacists were trained to assess and teach dry powder inhaler technique, using patient-centered educational tools including novel Inhaler Technique Labels. Interventions were delivered to patients at four visits over 6 months. At baseline, patients (Active: 53, CONTROL: 44) demonstrated poor inhaler technique (mean+/-S.D. score out of 9, 5.7+/-1.6). At 6 months, improvement in inhaler technique score was significantly greater in Active cf. CONTROL patients (2.8+/-1.6 cf. 0.9+/-1.4, p<0.001), and asthma severity was significantly improved (p=0.015). Qualitative responses from patients and pharmacists indicated a high level of satisfaction with the intervention and educational tools, both for their effectiveness and for their impact on the patient-pharmacist relationship. A simple feasible intervention in community pharmacies, incorporating daily reminders via Inhaler Technique Labels on inhalers, can lead to improvement in inhaler technique and asthma outcomes. Brief training modules and simple educational tools, such as Inhaler Technique Labels, can provide a low-cost and sustainable way of changing patient behavior in asthma, using community pharmacists as educators.

Multipass autogenous electron beam welding

International Nuclear Information System (INIS)

Murphy, J.L.; Mustaleski, T.M. Jr.; Watson, L.C.

1986-01-01

A multipass, autogenous welding procedure was developed for 7.6 mm (0.3 in.) wall thickness Type 304L stainless steel cylinders. The joint geometry has a 1.5 mm (0.06 in.) root-face width and a rectangular stepped groove that is 0.762 mm (0.03 in.) wide at the top of the root face and extends 1.5 mm in height, terminating into a groove width of 1.27 mm which extends to the outside of the 1.27 mm high weld-boss. One weld pass is made on the root, three passes on the 0.762 mm wide groove and three passes to complete the weld. Multipass, autogenous, electron beam welds maintain the characteristic high depth-to-width ratios and low heat input of single-pass, electron beam welds. The increased part distortion (which is still much less than from arc processes) in multipass weldments is corrected by a preweld machined compensation. Mechanical properties of multipass welds compare well with single-pass welds. The yield strength of welds in aluminum alloy 5083 is approximately the same for single-pass or multipass electron beam and gas, metal-arc welds. The incidence and size of porosity is less in multipass electron beam welding of aluminum as compared to gas, metal-arc welds. The multipass, autogenous, electron beam welding method has proven to be a reliable way to make some difficult welds in multilayer parts or in an instance where inside part temperature or weld underbead must be controlled and weld discontinuities must be minimized

Inhalant Dependence and its Medical Consequences

Directory of Open Access Journals (Sweden)

Mehmet Hamid Boztaş

2010-12-01

Full Text Available The term of inhalants is used for matters easily vapors. Inhalants are preferred for rapid, positive reinforcement and mild high effects. Products including inhalants are cheap, accessible, legal substances and are prevalently used in community. The prevalence of inhalant use in secondary schools in Turkey is about 5.1%. Inhalant substance dependence is generally observed within 14-15 age group. Age at first use could be as low as 5 to 6 years of age. Substance dependence is more probable in adults working in substance existing places. Inhalant usage is common in disadvantaged groups, children living in street, people with history of crimes, prison, depression, suicide, antisocial attitudes and conflict of family, history of abuse, violence and any other drug dependence and isolated populations. Inhalants are absorbed from lungs, after performing their quick and short effect metabolized by cytochrom P450 enzyme system except inhalant nitrites group which has a depressing effect like alcohol. In chronic use general atrophy, ventricular dilatation and wide sulcus were shown in cerebrum, cerebellum and pons by monitoring brain. Defects are mostly in periventricular, subcortical regions and in white matter. Demyelinization, hyperintensity, callosal slimming and wearing off in white and gray matter margins was also found. Ravages of brain shown by brain monitorisation are more and serious in inhalant dependence than in other dependences. It is important to decrease use of inhalants. Different approaches should be used for subcultures and groups in prevention. Prohibiting all the matters including inhalant is not practical as there are too many substances including inhalants. Etiquettes showing harmful materials can be used but this approach can also lead the children and adolescents recognize these substances easily.. Despite determintal effects of inhalant dependence, there are not yet sufficient number of studies conducted on prevention and

Influence of the arc plasma parameters on the weld pool profile in TIG welding

Science.gov (United States)

Toropchin, A.; Frolov, V.; Pipa, A. V.; Kozakov, R.; Uhrlandt, D.

2014-11-01

Magneto-hydrodynamic simulations of the arc and fluid simulations of the weld pool can be beneficial in the analysis and further development of arc welding processes and welding machines. However, the appropriate coupling of arc and weld pool simulations needs further improvement. The tungsten inert gas (TIG) welding process is investigated by simulations including the weld pool. Experiments with optical diagnostics are used for the validation. A coupled computational model of the arc and the weld pool is developed using the software ANSYS CFX. The weld pool model considers the forces acting on the motion of the melt inside and on the surface of the pool, such as Marangoni, drag, electromagnetic forces and buoyancy. The experimental work includes analysis of cross-sections of the workpieces, highspeed video images and spectroscopic measurements. Experiments and calculations have been performed for various currents, distances between electrode and workpiece and nozzle diameters. The studies show the significant impact of material properties like surface tension dependence on temperature as well as of the arc structure on the weld pool behaviour and finally the weld seam depth. The experimental weld pool profiles and plasma temperatures are in good agreement with computational results.

Influence of the arc plasma parameters on the weld pool profile in TIG welding

International Nuclear Information System (INIS)

Toropchin, A; Frolov, V; Pipa, A V; Kozakov, R; Uhrlandt, D

2014-01-01

Magneto-hydrodynamic simulations of the arc and fluid simulations of the weld pool can be beneficial in the analysis and further development of arc welding processes and welding machines. However, the appropriate coupling of arc and weld pool simulations needs further improvement. The tungsten inert gas (TIG) welding process is investigated by simulations including the weld pool. Experiments with optical diagnostics are used for the validation. A coupled computational model of the arc and the weld pool is developed using the software ANSYS CFX. The weld pool model considers the forces acting on the motion of the melt inside and on the surface of the pool, such as Marangoni, drag, electromagnetic forces and buoyancy. The experimental work includes analysis of cross-sections of the workpieces, highspeed video images and spectroscopic measurements. Experiments and calculations have been performed for various currents, distances between electrode and workpiece and nozzle diameters. The studies show the significant impact of material properties like surface tension dependence on temperature as well as of the arc structure on the weld pool behaviour and finally the weld seam depth. The experimental weld pool profiles and plasma temperatures are in good agreement with computational results

Numerical weld modeling - a method for calculating weld-induced residual stresses

International Nuclear Information System (INIS)

Fricke, S.; Keim, E.; Schmidt, J.

2001-01-01

In the past, weld-induced residual stresses caused damage to numerous (power) plant parts, components and systems (Erve, M., Wesseling, U., Kilian, R., Hardt, R., Bruemmer, G., Maier, V., Ilg, U., 1994. Cracking in Stabilized Austenitic Stainless Steel Piping of German Boiling Water Reactors - Characteristic Features and Root Causes. 20. MPA-Seminar 1994, vol. 2, paper 29, pp.29.1-29.21). In the case of BWR nuclear power plants, this damage can be caused by the mechanism of intergranular stress corrosion cracking in austenitic piping or the core shroud in the reactor pressure vessel and is triggered chiefly by weld-induced residual stresses. One solution of this problem that has been used in the past involves experimental measurements of residual stresses in conjunction with weld optimization testing. However, the experimental analysis of all relevant parameters is an extremely tedious process. Numerical simulation using the finite element method (FEM) not only supplements this method but, in view of modern computer capacities, is also an equally valid alternative in its own right. This paper will demonstrate that the technique developed for numerical simulation of the welding process has not only been properly verified and validated on austenitic pipe welds, but that it also permits making selective statements on improvements to the welding process. For instance, numerical simulation can provide information on the starting point of welding for every weld bead, the effect of interpass cooling as far as a possible sensitization of the heat affected zone (HAZ) is concerned, the effect of gap width on the resultant weld residual stresses, or the effect of the 'last pass heat sink welding' (welding of the final passes while simultaneously cooling the inner surface with water) producing compressive stresses in the root area of a circumferential weld in an austenitic pipe. The computer program FERESA (finite element residual stress analysis) was based on a commercially

Automatic welding of fuel elements

International Nuclear Information System (INIS)

Briola, J.

1958-01-01

The welding process depends on the type of fuel element, the can material and the number of cartridges to be welded: - inert-gas welding (used for G2 and the 1. set of EL3), - inert atmosphere arc welding (used for welding uranium and zirconium), - electronic welding (used for the 2. set of EL3 and the tank of Proserpine). (author) [fr

Vision-based weld pool boundary extraction and width measurement during keyhole fiber laser welding

Science.gov (United States)

Luo, Masiyang; Shin, Yung C.

2015-01-01

In keyhole fiber laser welding processes, the weld pool behavior is essential to determining welding quality. To better observe and control the welding process, the accurate extraction of the weld pool boundary as well as the width is required. This work presents a weld pool edge detection technique based on an off axial green illumination laser and a coaxial image capturing system that consists of a CMOS camera and optic filters. According to the difference of image quality, a complete developed edge detection algorithm is proposed based on the local maximum gradient of greyness searching approach and linear interpolation. The extracted weld pool geometry and the width are validated by the actual welding width measurement and predictions by a numerical multi-phase model.

Automatic welding machine for piping

International Nuclear Information System (INIS)

Yoshida, Kazuhiro; Koyama, Takaichi; Iizuka, Tomio; Ito, Yoshitoshi; Takami, Katsumi.

1978-01-01

A remotely controlled automatic special welding machine for piping was developed. This machine is utilized for long distance pipe lines, chemical plants, thermal power generating plants and nuclear power plants effectively from the viewpoint of good quality control, reduction of labor and good controllability. The function of this welding machine is to inspect the shape and dimensions of edge preparation before welding work by the sense of touch, to detect the temperature of melt pool, inspect the bead form by the sense of touch, and check the welding state by ITV during welding work, and to grind the bead surface and inspect the weld metal by ultrasonic test automatically after welding work. The construction of this welding system, the main specification of the apparatus, the welding procedure in detail, the electrical source of this welding machine, the cooling system, the structure and handling of guide ring, the central control system and the operating characteristics are explained. The working procedure and the effect by using this welding machine, and the application to nuclear power plants and the other industrial field are outlined. The HIDIC 08 is used as the controlling computer. This welding machine is useful for welding SUS piping as well as carbon steel piping. (Nakai, Y.)

Laser welding to expand the allowable gap in bore welding for ITER blanket hydraulic connection

Energy Technology Data Exchange (ETDEWEB)

Tanigawa, Hisashi, E-mail: tanigawa.hisashi@jaea.go.jp; Maruyama, Takahito; Noguchi, Yuto; Takeda, Nobukazu; Kakudate, Satoshi