Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 22
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Biol Futur ; 71(4): 359-370, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34554459

RESUMO

During coke production, large volume of effluent is generated, which has a very complex chemical composition and contains several toxic and carcinogenic substances, mainly aromatic compounds, cyanide, thiocyanate and ammonium. The composition of these high-strength effluents is very diverse and depends on the quality of coals used and the operating and technological parameters of coke ovens. In general, after initial physicochemical treatment, biological purification steps are applied in activated sludge bioreactors. This review summarizes the current knowledge on the anaerobic and aerobic transformation processes and describes key microorganisms, such as phenol- and thiocyanate-degrading, floc-forming, nitrifying and denitrifying bacteria, which contribute to the removal of pollutants from coke plant effluents. Providing the theoretical basis for technical issues (in this case the microbiology of coke plant effluent treatment) aids the optimization of existing technologies and the design of new management techniques.


Assuntos
Coque/efeitos adversos , Coque/microbiologia , Metalurgia/tendências , Eliminação de Resíduos Líquidos/normas , Qualidade da Água/normas , Humanos , Resíduos Industriais/efeitos adversos , Resíduos Industriais/análise , Metalurgia/normas , Esgotos/química , Eliminação de Resíduos Líquidos/métodos
2.
Injury ; 49 Suppl 1: S8-S11, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29929700

RESUMO

The evolution of plate fixation of fracture was accompanied by advances in metallurgy and improvement in understanding of the requirements for successful fracture healing. Locked internal fixation minimizes biologic damage and when used in conjunction with minimally invasive approaches may optimize fracture healing. Some current metal locked plate constructs may actually be too stiff, and various methods including screw modification, plate hole modification, and changes in plate material composition may provide a solution to optimize fracture healing. This paper reviews the evolution of plate design and describes the early clinical experience with the use of carbon fibre reinforced reinforced polyetheretherketone composite plates.


Assuntos
Placas Ósseas , Parafusos Ósseos , Fibra de Carbono , Cetonas , Metalurgia/tendências , Metais , Polietilenoglicóis , Benzofenonas , Fixação Interna de Fraturas/instrumentação , Consolidação da Fratura , Humanos , Teste de Materiais/métodos , Redução Aberta/instrumentação , Polímeros , Estresse Mecânico
3.
Health Phys ; 113(1): 13-22, 2017 07.
Artigo em Inglês | MEDLINE | ID: mdl-28542007

RESUMO

All soils and rocks contain naturally occurring radioactive materials (NORM). Many ores and raw materials contain relatively elevated levels of natural radionuclides, and processing such materials can further increase the concentrations of naturally occurring radionuclides. In the U.S., these materials are sometimes referred to as technologically-enhanced naturally occurring radioactive materials (TENORM). Examples of NORM minerals include uranium ores, monazite (a source of rare earth minerals), and phosphate rock used to produce phosphate fertilizer. The processing of these materials has the potential to result in above-background radiation exposure to workers. Following a brief review of the sources and potential for worker exposure from NORM in these varied industries, this paper will then present an overview of uranium mining and recovery in North America, including discussion on the mining methods currently being used for both conventional (underground, open pit) and in situ leach (ISL), also referred to as In Situ Recovery (ISR), and the production of NORM materials and wastes associated with these uranium recovery methods. The radiological composition of the NORM products and wastes produced and recent data on radiological exposures received by workers in the North American uranium recovery industry are then described. The paper also identifies the responsible government agencies in the U.S. and Canada assigned the authority to regulate and control occupational exposure from these NORM materials.


Assuntos
Metalurgia/estatística & dados numéricos , Mineração/estatística & dados numéricos , Exposição Ocupacional/estatística & dados numéricos , Resíduos Radioativos/estatística & dados numéricos , Urânio/análise , Metalurgia/tendências , Mineração/tendências , América do Norte , Exposição Ocupacional/prevenção & controle , Doses de Radiação , Urânio/isolamento & purificação
4.
Sci Total Environ ; 536: 142-149, 2015 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-26204050

RESUMO

This study attempts to speculate on the future of copper metabolism in China based on dynamic substance flow analysis. Based on tremendous growth of copper consumption over the past 63 years, China will depict a substantially increasing trend of copper in-use stocks for the next 30 years. The highest peak will be possibly achieved in 2050, with the maximum ranging between 163 Mt and 171 Mt. After that, total stocks are expected to slowly decline 147-154 Mt by the year 2080. Owing to the increasing demand of in-use stocks, China will continue to have a profound impact on global copper consumption with its high import dependence until around 2020, and the peak demand for imported copper are expected to approach 5.5 Mt/year. Thereafter, old scrap generated by domestic society will occupy an increasingly important role in copper supply. In around 2060, approximately 80% of copper resources could come from domestic recycling of old scrap, implying a major shift from primary production to secondary production. With regard to the effect of lifetime distribution uncertainties in different end-use sectors of copper stocks on the predict results, uncertainty evaluation was performed and found the model was relatively robust to these changes.


Assuntos
Cobre , Metalurgia/tendências , China , Previsões , Modelos Teóricos , Reciclagem , Incerteza
5.
ScientificWorldJournal ; 2013: 247035, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23533344

RESUMO

The course, technical progresses, and achievements of energy conservation of China steel industry (CSI) during 1980-2010 were summarized. Then, the paper adopted e-p method to analyze the variation law and influencing factors of energy consumptions of large- and medium-scale steel plants within different stages. It is pointed out that energy consumption per ton of crude steel has been almost one half lower in these thirty years, with 60% as direct energy conservation owing to the change of process energy consumption and 40% as indirect energy conservation attributed to the adjustment of production structure. Next, the latest research progress of some key common technologies in CSI was introduced. Also, the downtrend of energy consumption per ton of crude steel and the potential energy conservation for CSI during 2011-2025 were forecasted. Finally, it is indicated that the key topic of the next 15 years' research on the energy conservation of CSI is the synergistic operation of material flow and energy flow. It could be achieved by the comprehensive study on energy flow network optimization, such as production, allocation, utilization, recovery, reuse, and resource, according to the energy quantity, quality, and user demand following the first and second laws of thermodynamics.


Assuntos
Conservação de Recursos Energéticos/tendências , Metalurgia/tendências , Aço/química , China , Carvão Mineral , Eletricidade , Transferência de Energia , Temperatura Alta , Resíduos Industriais/análise , Resíduos Industriais/prevenção & controle , Termodinâmica
6.
G Ital Med Lav Ergon ; 34(3): 242-6, 2012.
Artigo em Italiano | MEDLINE | ID: mdl-23213796

RESUMO

A number of European directives and burocratic constraints give difficulties to the galvanic Italian industries: The situation of the Galvanic industry in Italy is examined, with special care about the innovation perspectives needed to maintain an important role for the Italian surface treatment processes in Italy. Alternatives are already present for zinc cyanic alkaline plating and for the passivation with chromates of zinc. Difficult instead is the substitution of bright nickel and of electroless autocatalytic nickel An important process is Plating On Plastics POP and on other non conducting materials with electroless nickel The substitution of colloidal Palladium for surface activation is proposed. New innovative processes are proposed, regarding composite depositions with powders of micron or nano size, pulsed current deposition and deposition of layers with structure controlled at nanometric level. A strict cooperation among Research centres, Universities and Industries can start the renewal of a production of fundamental importance for the Italian future.


Assuntos
Metalurgia/legislação & jurisprudência , Metalurgia/tendências , Europa (Continente) , Previsões , Itália , Metalurgia/métodos , Saúde Ocupacional
7.
Ann Occup Hyg ; 56(3): 362-72, 2012 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-22104319

RESUMO

BACKGROUND: Swedish foundries have a long tradition of legally required surveys in the workplace that, from the late 1960s onwards, included measurements of quartz. The availability of exposure data spanning almost 40 years presents a unique opportunity to study trends over that time and to evaluate the validity of exposure models based on data from shorter time spans. The aims of this study were (i) to investigate long-term trends in quartz exposure over time, (ii) using routinely collected quartz exposure measurements to develop a mathematical model that could predict both historical and current exposure patterns, and (iii) to validate this exposure model with up-to-date measurements from a targeted survey of the industry. METHODS: Eleven foundries, representative of the Swedish iron foundry industry, were divided into three groups based on the size of the companies, i.e. the number of employees. A database containing 2333 quartz exposure measurements for 11 different job descriptions was used to create three models that covered time periods which reflected different work conditions and production processes: a historical model (1968-1989), a development model (1990-2004), and a validation model (2005-2006). A linear mixed model for repeated measurements was used to investigate trends over time. In all mixed models, time period, company size, and job title were included as fixed (categorical) determinants of exposure. The within- and between-worker variances were considered to be random effects. A linear regression analysis was performed to investigate agreement between the models. The average exposure was estimated for each combination of job title and company size. RESULTS: A large reduction in exposure (51%) was seen between 1968 and 1974 and between 1975 and 1979 (28%). In later periods, quartz exposure was reduced by 8% per 5 years at best. In the first period, employees at smaller companies experienced ~50% higher exposure levels than those at large companies, but these differences became much smaller in later years. The furnace and ladle repair job were associated with the highest exposure, with 3.9-8.0 times the average exposure compared to the lowest exposed group. Without adjusting for this autonomous trend over time, predicting early historical exposures using our development model resulted in a statistically significant regression coefficient of 2.42 (R(2) = 0.81), indicating an underestimation of historical exposure levels. Similar patterns were seen for other historical time periods. Comparing our development model with our validation model resulted in a statistically significant regression coefficient of 0.31, indicating an overestimation of current exposure levels. CONCLUSION: To investigate long-term trends in quartz exposure over time, overall linear trends can be determined by using mixed model analysis. To create individual exposure measures to predict historical exposures, it is necessary to consider factors such as the time period, type of job, type of company, and company size. The mixed model analysis showed systematic changes in concentration levels, implying that extrapolation of exposure estimates outside the range of years covered by measurements may result in underestimation or overestimation of exposure.


Assuntos
Poluentes Atmosféricos/análise , Ferro , Exposição Ocupacional/análise , Exposição Ocupacional/estatística & dados numéricos , Quartzo/análise , Monitoramento Ambiental/métodos , Monitoramento Epidemiológico , Humanos , Metalurgia/tendências , Reprodutibilidade dos Testes , Suécia/epidemiologia , Níveis Máximos Permitidos , Fatores de Tempo
8.
G Ital Med Lav Ergon ; 33(3): 228-33, 2011.
Artigo em Italiano | MEDLINE | ID: mdl-22073665

RESUMO

Analysis of the evolution drivers of the management systems in the metalworking industry, mainly characterized as "automotive", starting with the "mass production" model, followed for the development of Italian industry in the '50. Through the socio-economic changes of the '90/10, the metalworking plants were deeply restructured with the introduction of computers in the production systems, and then with the first global benchmarks such as the "lean production", towards the needed operational flexibility to respond to the market dynamics. Plants change radically, company networks become real, ICT services are fundamental elements for the integration. These trends help visualizing a new "Factory of the Future" for the years 2020/30, where the competition will be based on the socio-economical, technological and environmental factors included in the "Competitive Sustainable Manufacturing" paradigm.


Assuntos
Metalurgia/história , Previsões , História do Século XX , História do Século XXI , Humanos , Itália , Metalurgia/organização & administração , Metalurgia/tendências
9.
G Ital Med Lav Ergon ; 33(3): 245-51, 2011.
Artigo em Italiano | MEDLINE | ID: mdl-22073668

RESUMO

Among the health risk for workers employed in metal working those related to cutting fluids were traditionally prominent. The main effects concerned respiratory and dermal pathologies from irritative-allergic (both chemical and biological) to mutagen and carcinogenic. These two latest effects have been demonstrated to increase with time of use. The attempt to reduce the chemical risks due to cutting fluid historically moved trough the constant decrease of mineral oil components by increasing their refinery. The innovative technological and preventive approach here presented consists on the contrary in changing the fluid basis with natural vegetal esters. The results confirmed similar or better technical characteristics of the fluids and a significant reduction of air pollution for example for polycyclic aromatic hydrocarbons (PAH) mixture, i.e. the most measured and studied toxic agents exposure to metal cutting fluid.


Assuntos
Metalurgia , Doenças Profissionais/induzido quimicamente , Doenças Profissionais/prevenção & controle , Exposição Ocupacional/efeitos adversos , Humanos , Lubrificação , Metalurgia/métodos , Metalurgia/tendências , Refrigeração
10.
Sci Total Environ ; 409(20): 4326-34, 2011 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-21788063

RESUMO

The environment around metal industries, such as smelters, is often highly contaminated due to continuous deposition of metals. We studied nest box breeding populations of pied flycatchers (Ficedula hypoleuca) in a well-studied pollution gradient from a sulfide ore smelter in Northern Sweden, after reduced aerial metal emissions (by 93-99%) from the smelter. The deposition of arsenic, cadmium, copper and zinc (based on moss samples) reflected the reduced emissions fairly well. However, nestling pied flycatchers had similar concentrations of these elements and mercury in tissues (bone, liver and blood) and feces in the 2000s, as in the 1980s, when the emissions were substantially higher. The exposure to high metal concentrations in the close vicinity of the smelter resulted in inhibited ALAD activities, depressed hemoglobin and hematocrit levels and increased mortality of nestlings. Our results indicate that in the highly contaminated environment around the smelter, nestlings reflected the slowly cycling soil pool, rather than the atmospheric deposition, and the concentration in soils plays an important role for the response of pied flycatchers to reduced atmospheric deposition.


Assuntos
Poluentes Atmosféricos/toxicidade , Exposição Ambiental/análise , Metalurgia , Metais Pesados/toxicidade , Reprodução/efeitos dos fármacos , Aves Canoras/crescimento & desenvolvimento , Poluentes Atmosféricos/análise , Animais , Metalurgia/normas , Metalurgia/tendências , Metais Pesados/análise , Suécia
11.
Environ Sci Technol ; 45(1): 182-8, 2011 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-21121663

RESUMO

A dynamic material flow model was used to analyze the patterns of iron stocks in use for six industrialized countries. The contemporary iron stock in the remaining countries was estimated assuming that they follow a similar pattern of iron stock per economic activity. Iron stocks have reached a plateau of about 8-12 tons per capita in the United States, France, and the United Kingdom, but not yet in Japan, Canada, and Australia. The global average iron stock was determined to be 2.7 tons per capita. An increase to a level of 10 tons over the next decades would deplete about the currently identified reserves. A subsequent saturation would open a long-term potential to dramatically shift resource use from primary to secondary sources. The observed saturation pattern implies that developing countries with rapidly growing stocks have a lower potential for recycling domestic scrap and hence for greenhouse gas emissions saving than industrialized countries, a fact that has not been addressed sufficiently in the climate change debate.


Assuntos
Países Desenvolvidos/estatística & dados numéricos , Ferro , Metalurgia/estatística & dados numéricos , Austrália , Canadá , Comércio , Conservação dos Recursos Naturais , Materiais de Construção/economia , Materiais de Construção/estatística & dados numéricos , Países Desenvolvidos/economia , Países em Desenvolvimento/economia , Países em Desenvolvimento/estatística & dados numéricos , França , Ferro/economia , Japão , Metalurgia/tendências , Alocação de Recursos , Reino Unido , Estados Unidos
12.
Neurosurgery ; 64(5 Suppl 2): 199-214; discussion 214-5, 2009 May.
Artigo em Inglês | MEDLINE | ID: mdl-19404101

RESUMO

SHAPE MEMORY ALLOYS possess distinct dynamic properties with particular applications in neurosurgery. Because of their unique physical characteristics, these materials are finding increasing application where resiliency, conformation, and actuation are needed. Nitinol, the most frequently manufactured shape memory alloy, responds to thermal and mechanical stimuli with remarkable mechanical properties such as shape memory effect, super-elasticity, and high damping capacity. Nitinol has found particular use in the biomedical community because of its excellent fatigue resistance and biocompatibility, with special interest in neurosurgical applications. The properties of nitinol and its diffusionless phase transformations contribute to these unique mechanical capabilities. The features of nitinol, particularly its shape memory effect, super-elasticity, damping capacity, as well as its biocompatibility and biomechanics are discussed herein. Current and future applications of nitinol and other shape memory alloys in endovascular, spinal, and minimally invasive neurosurgery are introduced. An understanding of the metallurgic properties of nitinol provides a foundation for further exploration of its use in neurosurgical implant design.


Assuntos
Ligas/uso terapêutico , Procedimentos Neurocirúrgicos/instrumentação , Próteses e Implantes/tendências , Ligas/química , Materiais Biocompatíveis/química , Materiais Biocompatíveis/uso terapêutico , Fenômenos Biomecânicos/fisiologia , Desenho de Equipamento/métodos , Desenho de Equipamento/tendências , Humanos , Metalurgia/métodos , Metalurgia/tendências , Procedimentos Neurocirúrgicos/métodos , Próteses e Implantes/ultraestrutura , Estresse Mecânico
13.
Health Phys ; 91(5): 489-93, 2006 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-17033460

RESUMO

With more than 80 reported/confirmed accidental melts worldwide since 1983 and still counting, potential contamination by radioactive materials remains as a major concern among recycled scrap and steel companies. Some of these events were catastrophic and have cost the industry millions of dollars in business and, at the same time, resulted in declining consumer confidence. It is also known that more events with confirmed radioactive contamination have occurred that involve mining of old steel slag and skull dumps. Consequently, the steel industry has since undergone massive changes that incurred unprecedented expenses through the installation of radiation monitoring systems in hopes of preventing another accidental melt. Despite such extraordinary efforts, accidental melts continue to occur and plague the industry. One recent reported/confirmed event occurred in the Republic of China in 2004, causing the usual lengthy shutdown for expensive decontamination efforts before the steel mill could resume operations. With this perspective in mind, the metal industry has a long-standing opposition to the release of radioactive materials of any kind to commerce for fear of contamination and the potential consequences.


Assuntos
Indústrias/tendências , Metalurgia/tendências , Metais , Proteção Radiológica/métodos , Resíduos Radioativos/prevenção & controle , Gestão de Riscos/tendências , Gerenciamento de Resíduos/métodos , Tomada de Decisões , Fatores de Risco , Gestão de Riscos/métodos , Estados Unidos
14.
Health Phys ; 91(5): 494-7, 2006 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-17033461

RESUMO

The current U.S. economic environment for the disposition of radioactive waste, including very-low-activity metals, is currently experiencing relatively low radioactive disposal costs and readily available disposal space. Despite the recent market increase in demand for recycled scrap metal commodities, there is still little change in the behavior of the nuclear industry (including radioactive waste processors and radioactive scrap metal recyclers) to pursue the recycling of potentially contaminated scrap metal. The relatively low cost of traditional radioactive waste disposal combined with the perceived risks associated with recycling of previously contaminated metals means that most U.S. radioactive facility managers and stakeholders will elect not to recycle. Current technology exists and precedence has been set for prescreening (by means of bulk radioactive assay techniques) scrap metal that is not contaminated and diverting it to industrial landfills for disposal. Other processes also allow some radiologically contaminated metals to be melted and recast into products with low, but acceptable, activity levels for restricted use in the nuclear industry. A new concept is being considered that would create a centralized licensed facility for the process and disposition of "very-low-activity" metals for "directed first use." The advantages to this type of approach would include a standardized method for licensing the clearance process.


Assuntos
Indústrias/tendências , Metalurgia/tendências , Metais , Proteção Radiológica/métodos , Resíduos Radioativos/prevenção & controle , Gestão de Riscos/tendências , Gerenciamento de Resíduos/métodos , Tomada de Decisões , Fatores de Risco , Gestão de Riscos/métodos , Estados Unidos
16.
Med Device Technol ; 16(8): 9-11, 2005 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-16355962

RESUMO

Titanium (Ti) provides the basis for many alloys used in medical technology. These alloys have been discussed many times in this column over the past decade. In recent years in particular, there have been a number of developments in Ti metallurgy, which suggests that a reappraisal of these alloy systems is timely.


Assuntos
Ligas/química , Materiais Biocompatíveis/química , Metalurgia/métodos , Metalurgia/tendências , Próteses e Implantes , Titânio/química , Transição de Fase
17.
J Hist Behav Sci ; 41(3): 269-84, 2005.
Artigo em Inglês | MEDLINE | ID: mdl-15981239

RESUMO

The Colorado Fuel and Iron Company's Sociological Department represented an industrial welfare plan based on an early understanding of applied sociology. The Department was created as a response to the demands of integrating coal and coke production with steel manufacturing, and the necessity of combating strikes among the immigrant workers. The "settlement house model" used by the Sociological Department was intended to foster labor stability by transforming the lifestyles and habits of the immigrant workers and their families. It is concluded that the industrial welfare programs that were intended to inspire loyalty to the company merely added to the workers' grievances with the company.


Assuntos
Planejamento em Saúde/história , Metalurgia/história , Paternalismo , Sociologia/história , Colorado , Emigração e Imigração , Planejamento em Saúde/tendências , História do Século XIX , História do Século XX , Humanos , Ferro , Sindicatos/história , Metalurgia/organização & administração , Metalurgia/tendências , Seguridade Social/história , Aço
20.
ScientificWorldJournal ; 2: 1667-75, 2002 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-12806160

RESUMO

For the last 2 decades, special attention has been paid to arsenic due to its high concentration in groundwater in many regions of the globe. There are not very many reports on arsenic concentration in the Finnish ecosystem, although the metal has been known to be highly toxic since ancient times. For the majority of people in Finland, the leading exposure route to arsenic is through food consumption. In this study, it has been observed that atmospheric emissions of arsenic from anthropogenic sources have decreased by 90%, which is due to better control technology and strict regulation. Aquatic discharge also was attenuated from 7.1 metric tons (t) in 1990 to 0.7 t in 1999. The concentration of arsenic aerosols in the atmosphere in Finland varies between 0.46 to 0.75 ng m(-3). Its use in pesticides and insecticides also has been phased out in Finland. There is no information available regarding arsenic species in the Finnish environment. Elevated concentrations of arsenic in groundwater has been reported for many countries. In Finland two hot spots are reported--one in the south of Finland and the second in Lapland. In these areas, arsenic concentration in well water is greater than 10 microg l(-1) (WHO recommended value: <10 microg l(-1)). It is believed that the release of arsenic into the Finnish groundwater is geogenic.


Assuntos
Arsênio/química , Arsênio/metabolismo , Atmosfera/análise , Ecossistema , Poluentes Atmosféricos/química , Poluentes Atmosféricos/metabolismo , Atmosfera/química , Monitoramento Ambiental/métodos , Finlândia , Combustíveis Fósseis , Humanos , Incineração , Resíduos Industriais , Metalurgia/tendências , Centrais Elétricas/tendências , Poluentes Químicos da Água/metabolismo , Abastecimento de Água/análise
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...