WorldWideScience

Sample records for cement industry tendencias

  1. US cement industry

    Energy Technology Data Exchange (ETDEWEB)

    Nisbet, M.A.

    1997-12-31

    This paper describes the cement and concrete industry, and provides data on energy use and carbon dioxide emissions. The potential impact of an energy tax on the industry is briefly assessed. Opportunities identified for reducing carbon dioxide emissions include improved energy efficiency, alternative fuels, and alternative materials. The key factor in determining CO{sub 2} emissions is the level of domestic production. The projected improvement in energy efficiency and the relatively slow growth in domestic shipments indicate that CO{sub 2} emissions in 2000 should be about 5% above the 1990 target. However, due to the cyclical nature of cement demand, emissions will probably be above target levels during peak demand and below target levels during demand troughs. 7 figs., 2 tabs.

  2. Tendencies in the energy consumption and in the carbon dioxide emissions in the Mexican cement industry; Tendencias del consumo de energia y emisiones de bioxido de carbono de la industria cementera mexicana

    Energy Technology Data Exchange (ETDEWEB)

    Ozawa M, Leticia; Sheinbaum P, Claudia [Instituto de Ingenieria UNAM, Mexico, D. F. (Mexico)

    1996-12-31

    This paper analyzes the changes occurred in the energy consumption and carbon dioxide in the Mexican cement industry. For this purpose, the energy consumption and the emissions are broken up into three types of changes that affect the energy demand of an industry: activity, structure and energy intensity. According to this analysis it is found that the Mexican cement industry has suffered an important reduction in the energy intensity as a result of the disappearance, almost complete, of the wet production process, of the increment in the production of pozzolanic cement and in the opening of new high technology industries. With respect to the intensity of carbon dioxide emissions it does not decrease at the same rate than the energy intensity due to the increased consumption of the fuel oil over the natural gas. At the end of this paper an international comparison is presented of the energy specific consumption and of its emissions. [Espanol] En este articulo se analizan los cambios ocurridos en el consumo de energia y emisiones de bioxido de carbono de la industria cementera mexicana. Para ello, se desagrega el consumo de energia y las emisiones en tres tipos de cambios que influyen en la demanda energetica de una industria: actividad, estructura, e intensidad energetica. De acuerdo con este analisis se encuentra que la industria cementera mexicana ha sufrido un importante decremento en la intensidad energetica producto de la desaparicion, casi por completo, del proceso de produccion por via humeda, del incremento en la produccion del cemento puzolanico y de la apertura de nuevas industrias con alta tecnologia. Por su parte, la intensidad en las emisiones de bioxido de carbono no disminuye a la misma tasa que la intensidad energetica debido al incremento en el uso del combustoleo sobre el gas natural. Al final del articulo se presenta una comparacion internacional del consumo especifico de energia y de las emisiones.

  3. Thoughts on the Current Cement Industry Development

    Institute of Scientific and Technical Information of China (English)

    Gan Zhihe

    2003-01-01

    According to the analysis of cement capacity andits relations with macro economy running index, the mainreasons for the present rapid development of cement capacityare the rapid development of economy and the shot up ofwhole society fixed asset investment. According to the presentspeed of economy development, cement still enjoys a po-tential increase, So here has not been an overall excessivepopularity of cement industry. The best way to prevent lowlevel repeated construction is to promote the development ofnew dry- process cement as well as try to get rid of blindness.

  4. Basic Chemistry for the Cement Industry.

    Science.gov (United States)

    Turner, Mason

    This combined student workbook and instructor's guide contains nine units for inplant classes on basic chemistry for employees in the cement industry. The nine units cover the following topics: chemical basics; measurement; history of cement; atoms; bonding and chemical formulas; solids, liquids, and gases; chemistry of Portland cement…

  5. Case Study of the California Cement Industry

    Energy Technology Data Exchange (ETDEWEB)

    Coito, Fred; Powell, Frank; Worrell, Ernst; Price, Lynn; Friedmann, Rafael

    2005-05-01

    California is the largest cement producing state in theU.S., accounting for between 10 percent and 15 percent of U.S. cementproduction and cement industry employment. The cement industry inCalifornia consists of 31 sites that consume large amounts of energy,annually: 1,600 GWh of electricity, 22 million therms of natural gas, 2.3million tons of coal, 0.25 tons of coke, and smaller amounts of wastematerials, including tires. The case study summarized in this paperfocused on providing background information, an assessment ofenergy-efficiency opportunities and barriers, and program recommendationsthat can be used by program planners to better target products to thecement industry. The primary approach to this case study involvedwalk-through surveys of customer facilities and in depth interviews withcustomer decision makers and subsequent analysis of collected data. Inaddition, a basic review of the cement production process was developed,and summary cement industry energy and economic data were collected, andanalyzed. The analysis of secondary data provides background informationon the cement industry and identification of potential energy-efficiencyopportunities. The interviews provide some understanding of the customerperspective about implementation of energy-efficiencyprojects.

  6. Trends in the energy use in the Mexican industrial sector; Tendencias del uso de la energia en el sector industrial mexicano

    Energy Technology Data Exchange (ETDEWEB)

    Sheinbaum, C. [UNAM, Mexico, D. F. (Mexico); Jauregui, I. [CONAE, Mexico, D. F. (Mexico)

    1995-12-31

    This paper presents an analysis of the trends of the energy use for the industry in Mexico. For the various industrial branches (mining, construction, chemical, sugar, cement, paper and cellulose and glass) the changes in energy intensity (measured as the use of the energy divided by the aggregated value) and in the participation of the same in the industrial Internal Gross Product are presented. This is developed by means of the analysis of Laspeyress exchange indexes. It is found that in most of the industrial branches a reduction of the energy density has been originated. The reasons for the falling of this indicator are structural and of technological change nature, depending on the industrial branch. Nevertheless the classical analysis of the Laspeyress indexes is not sufficient to explain the changes occurred in the energy intensity in the Mexican industry for the last years. [Espanol] Este articulo presenta un analisis de las tendencias del uso de la energia para la industria en Mexico. Para las diversas ramas industriales (mineria, construccion, quimica, azucar, cemento, papel y celulosa y vidrio) se presentan los cambios en la intensidad energetica (medida como uso de la energia entre valor agregado) y en la participacion de las mismas en el Producto Interno Bruto (PIB) industrial. Esto se desarrolla por medio del analisis de indices de cambio de Laspeyress. Se encuentra que en la mayoria de las ramas industriales hubo una disminucion en la intensidad energetica. Las razones de la caida de este indicador son estructurales y de cambio tecnologico dependiendo de la rama industrial. Sin embargo el analisis clasico de los indices de Laspeyress es insuficiente para explicar los cambios ocurridos en la intensidad energetica de la industria mexicana para los ultimos anos.

  7. Sustainable Development of the Cement Industry and Blended Cements to Meet Ecological Challenges

    OpenAIRE

    Konstantin Sobolev

    2003-01-01

    The world production of cement has greatly increased in the past 10 years. This trend is the most significant factor affecting technological development and the updating of manufacturing facilities in the cement industry. Existing technology for the production of cement clinker is ecologically damaging; it consumes much energy and natural resources and also emits pollutants. A new approach to the production of blended or high-volume mineral additive (HVMA) cement helps to improve its ecologi...

  8. Sustainable development of the cement industry and blended cements to meet ecological challenges.

    Science.gov (United States)

    Sobolev, Konstantin

    2003-05-05

    The world production of cement has greatly increased in the past 10 years. This trend is the most significant factor affecting technological development and the updating of manufacturing facilities in the cement industry. Existing technology for the production of cement clinker is ecologically damaging; it consumes much energy and natural resources and also emits pollutants. A new approach to the production of blended or high-volume mineral additive (HVMA) cement helps to improve its ecological compatibility. HVMA cement technology is based on the intergrinding of portland cement clinker, gypsum, mineral additives, and a special complex admixture. This new method increases the compressive strength of ordinary cement, improves durability of the cement-based materials, and--at the same time--uses inexpensive natural mineral additives or industrial by-products. This improvement leads to a reduction of energy consumption per unit of the cement produced. Higher strength, better durability, reduction of pollution at the clinker production stage, and decrease of landfill area occupied by industrial by-products, all provide ecological advantages for HVMA cement.

  9. Sustainable Development of the Cement Industry and Blended Cements to Meet Ecological Challenges

    Directory of Open Access Journals (Sweden)

    Konstantin Sobolev

    2003-01-01

    Full Text Available The world production of cement has greatly increased in the past 10 years. This trend is the most significant factor affecting technological development and the updating of manufacturing facilities in the cement industry. Existing technology for the production of cement clinker is ecologically damaging; it consumes much energy and natural resources and also emits pollutants. A new approach to the production of blended or high-volume mineral additive (HVMA cement helps to improve its ecological compatibility. HVMA cement technology is based on the intergrinding of portland cement clinker, gypsum, mineral additives, and a special complex admixture. This new method increases the compressive strength of ordinary cement, improves durability of the cement-based materials, and - at the same time - uses inexpensive natural mineral additives or industrial by-products. This improvement leads to a reduction of energy consumption per unit of the cement produced. Higher strength, better durability, reduction of pollution at the clinker production stage, and decrease of landfill area occupied by industrial by-products, all provide ecological advantages for HVMA cement.

  10. Copper Slag Blended Cement: An Environmental Sustainable Approach for Cement Industry in India

    Directory of Open Access Journals (Sweden)

    Jagmeet Singh

    2016-04-01

    Full Text Available Indian cement industry is facing environmental issue of emission of carbon dioxide (CO2, a greenhouse gas. Blended cements including supplementary cementitious materials are substitute of Portland cement to reduce CO2 emission. The present paper investigates theappropriateness of copper slag (CS as supplementary cementitious material. Strength properties and hydration of mixes were determined at different replacement levels of CS with cement. Compressive, flexural and tensile strength of each mix was found out at different curing periods. The hydration of cement was investigated through X-ray diffraction (XRD. The strength test results showed that substitution of up to 20% of CS can significantly replace Portland cement.XRD test results were corresponding to strength test results. The present study encourages the utilization of CS as supplementary cementitious material to make economical and environmentally sustainable blended cement

  11. Secondary fuels and raw materials in the Spanish cement industry

    Energy Technology Data Exchange (ETDEWEB)

    Gordobil, J.C.U.; Guede, Elena [Cementos Lemona s.a. (Spain)

    1997-03-01

    The growing environmental and energy concern are having an impact on the Spanish cement industry. This article describes the impact on waste management, the operation of cement kilns and the possibility for recycling. Current projects and future prospects are described. (UK)

  12. Production of cement requiring low energy expenditure. An industrial test

    Energy Technology Data Exchange (ETDEWEB)

    Gimenez, S.; Blanco, M.T.; Palomo, A.; Puertas, F. (Instituto de Ciencias de la Construccion, Madrid (Spain))

    1991-01-01

    A new method for making cement is proposed. It is based on the use of CaF{sub 2} and CaSO{sub 4} for partial replacement of the usual raw materials in cement manufacturing. This paper shows the feasibility of the proposed method on an industrial scale. A test carried out in a Spanish cement factory (1500 t yield of the new cement) has revealed that the mehtod can not only be adapted to the current technology but also requires a much lower energy expenditure. The final product is shown to have excellent properties in comparison with OPC. (orig.).

  13. TECHNOLOGICAL CHANGES IN THE CEMENT MANUFACTURING INDUSTRY.

    Science.gov (United States)

    WESSON, CARL E.

    THE PURPOSE OF THIS STUDY IS TO PRESENT A PRELIMINARY PICTURE OF OCCUPATIONAL CHANGES BROUGHT ABOUT IN THE MANUFACTURE OF CEMENT AS A RESULT OF INTRODUCING AUTOMATED EQUIPMENT. ONE AUTOMATED AND SEVERAL CONVENTIONAL TYPE CEMENT PLANTS WERE STUDIED. ANALYSIS OF DATA OBTAINED THROUGH RESEARCH AND DATA COLLECTED DURING THE STUDY REVEALED THAT…

  14. Plant Test of Industrial Waste Disposal in a Cement Kiln

    Institute of Scientific and Technical Information of China (English)

    刘阳生; 韩杰; 等

    2003-01-01

    Destruction of industrial waste in cement rotary kilins(CRKs) is an alternative technology for the treatment of certain types of industrial waste(IW).In this paper,three typical types of industrial wastes were co-incinerated in the CRK at Beijing Cement Plant to determine the effects of waste disposal(especially solid waste disposal )on the quality of clinker and the concentration of pollutants in air emission.Experimental results show that(1) waste disposal does not affect the quality of clinker and fly ash,and fly ash after the IW disposal can still be used in the cement production,(2) heavy metals from IW are immobilized and stabilized in the clinker and cement,and (3) concentration of pollutants in air emission is far below than the permitted values in the China National Standard-Air Pollutants Emission Standard(GB 16297-1996).

  15. Global warming impact on the cement and aggregates industries

    Energy Technology Data Exchange (ETDEWEB)

    Davidovits, J. (Cordi-Geopolymere SA, Saint-Quentin (France). Geopolymer Inst.)

    1994-06-01

    CO[sub 2] related energy taxes are focusing essentially on fuel consumption, not on actual CO[sub 2] emission measured at the chimneys. Ordinary Portland cement, used in the aggregates and industries, results from the calcination of limestone and silica. The production of 1 ton of cement directly generates 0.55 tons of chemical-CO[sub 2] and requires the combustion of carbon-fuel to yield an additional 0.40 tons of CO[sub 2]. The 1987 1 billion metric tons world production of cement accounted for 1 billion metric tons of CO[sub 2], i.e., 5% of the 1987 world CO[sub 2] emission. A world-wide freeze of CO[sub 2] emission at the 1990 level as recommended by international institutions, is incompatible with the extremely high cement development needs of less industrialized countries. Present cement production growth ranges from 5% to 16% and suggests that in 25 years from now, world cement CO[sub 2] emissions could equal 3,500 million tons. Eco-taxes when applied would have a spectacular impact on traditional Portland cement based aggregates industries. Taxation based only on fuel consumption would lead to a cement price increase of 20%, whereas taxation based on actual CO[sub 2] emission would multiply cement price by 1.5 to 2. A 25--30% minor reduction of CO[sub 2] emissions may be achieved through the blending of Portland cement with replacement materials such as coal-fly ash and iron blast furnace slag.

  16. Potential for energy conservation in the cement industry

    Energy Technology Data Exchange (ETDEWEB)

    Garrett-Price, B.A.

    1985-02-01

    This report assesses the potential for energy conservation in the cement industry. Energy consumption per ton of cement decreased 20% between 1972 and 1982. During this same period, the cement industry became heavily dependent on coal and coke as its primary fuel source. Although the energy consumed per ton of cement has declined markedly in the past ten years, the industry still uses more than three and a half times the fuel that is theoretically required to produce a ton of clinker. Improving kiln thermal efficiency offers the greatest opportunity for saving fuel. Improving the efficiency of finish grinding offers the greatest potential for reducing electricity use. Technologies are currently available to the cement industry to reduce its average fuel consumption per ton by product by as much as 40% and its electricity consumption per ton by about 10%. The major impediment to adopting these technologies is the cement industry's lack of capital as a result of low or no profits in recent years.

  17. Cement Industry Overview and Market Price Forecasting In Azerbaijan

    Directory of Open Access Journals (Sweden)

    Latafat Gardashova

    2016-10-01

    Full Text Available Global economic situation and energy resources’ prices influence local economic trends, investment of capital, status of financial institutions and cement industry in Azerbaijan in whole. These trends influence demand and activities of cement business communities which start to optimize expenses and find new priority decisions in business. Moreover some independent economic analysts refer to forecasts that since 2016 yearly demand will increase 4-5% in Azerbaijan. Objectives are to forecast cement price in the market using Fuzzy c-means (together with Fuzzy Inference System and ANFIS which are entered MATLAB mathematical packet and to compare the results of these methods.Taking into consideration the results of research and applied forecast models the cement price can show the stable slow increasing in the market even there is probability of some periodic fluctuations and regulating actions by the state authorities. Therefore it is high probability that the cement price will increase next 1-2 years.

  18. Application of Carbonate Looping to Cement Industry

    DEFF Research Database (Denmark)

    Lin, Weigang; Illerup, Jytte Boll; Dam-Johansen, Kim

    2012-01-01

    In the present work, cycle experiments of different types of limestone, cement raw meal and a mixture of limestone and clay were carried out in laboratory scale setups at more realistic conditions (i.e. calcination temperature is 950°C and CO2 concentration is 80%) to simulate the performance...... with an increase in the CO2 partial pressure during calcination, indicating enhancement of sintering by the presence of CO2. As sorbents, cement raw meal and the mixture of limestone and clay show a similar trend as limestone with respect to the decay of the CO2 carrying capacity and this capacity is lower than...... that of limestone at the same conditions in most cases. SEM and XRD analyses indicate that a combination of severe sintering and formation of calcium silicates attributes to the poor performance of the cement raw meal....

  19. Cement Industry Overview and Market Price Forecasting In Azerbaijan

    OpenAIRE

    2016-01-01

    Global economic situation and energy resources’ prices influence local economic trends, investment of capital, status of financial institutions and cement industry in Azerbaijan in whole. These trends influence demand and activities of cement business communities which start to optimize expenses and find new priority decisions in business. Moreover some independent economic analysts refer to forecasts that since 2016 yearly demand will increase 4-5% in Azerbaijan. Objectives are to forecast c...

  20. Pulverized coal and substitute fuels for the cement manufacturing industry

    Energy Technology Data Exchange (ETDEWEB)

    Dobrowsky, F.

    1981-01-01

    This paper comprises an article of general technical interest on coal and its use in the cement industry, plus the scope for using substitute fuels. Discusses coal properties and preparation (crushing). Describes the heating systems of the cement ovens: burners, combustion and parameters governing flame-length. Looks at operation problems connected with heating of the coal: caking, fusing, clinker quality and behaviour of the refractory bricks. Also discusses substitute fuels: type of fuel, scope for utilisation and requisite precautions. 32 refs.

  1. Alternative fuels in cement industry; Alternativa braenslen i cementindustrin

    Energy Technology Data Exchange (ETDEWEB)

    Nyman, K.E.; Ek, R. [Finnsementti Oy, Parainen (Finland); Maekelae, K. [Finreci Oy (Finland)

    1997-10-01

    In this project the cement industry`s possibilities to replace half of the fossil fuels with waste derived fuels are investigated. Bench-scale experiments, pilot plant tests and full scale tests have been done with used tires and plastics wastes

  2. Carbon Capture in the Cement Industry: Technologies, Progress, and Retrofitting.

    Science.gov (United States)

    Hills, Thomas; Leeson, Duncan; Florin, Nicholas; Fennell, Paul

    2016-01-05

    Several different carbon-capture technologies have been proposed for use in the cement industry. This paper reviews their attributes, the progress that has been made toward their commercialization, and the major challenges facing their retrofitting to existing cement plants. A technology readiness level (TRL) scale for carbon capture in the cement industry is developed. For application at cement plants, partial oxy-fuel combustion, amine scrubbing, and calcium looping are the most developed (TRL 6 being the pilot system demonstrated in relevant environment), followed by direct capture (TRL 4-5 being the component and system validation at lab-scale in a relevant environment) and full oxy-fuel combustion (TRL 4 being the component and system validation at lab-scale in a lab environment). Our review suggests that advancing to TRL 7 (demonstration in plant environment) seems to be a challenge for the industry, representing a major step up from TRL 6. The important attributes that a cement plant must have to be "carbon-capture ready" for each capture technology selection is evaluated. Common requirements are space around the preheater and precalciner section, access to CO2 transport infrastructure, and a retrofittable preheater tower. Evidence from the electricity generation sector suggests that carbon capture readiness is not always cost-effective. The similar durations of cement-plant renovation and capture-plant construction suggests that synchronizing these two actions may save considerable time and money.

  3. Energy Efficiency Improvement Opportunities for the Cement Industry

    Energy Technology Data Exchange (ETDEWEB)

    Price, Lynn; Worrell, Ernst; Galitsky, Christina; Price, Lynn

    2008-01-31

    This report provides information on the energy savings, costs, and carbon dioxide emissions reductions associated with implementation of a number of technologies and measures applicable to the cement industry. The technologies and measures include both state-of-the-art measures that are currently in use in cement enterprises worldwide as well as advanced measures that are either only in limited use or are near commercialization. This report focuses mainly on retrofit measures using commercially available technologies, but many of these technologies are applicable for new plants as well. Where possible, for each technology or measure, costs and energy savings per tonne of cement produced are estimated and then carbon dioxide emissions reductions are calculated based on the fuels used at the process step to which the technology or measure is applied. The analysis of cement kiln energy-efficiency opportunities is divided into technologies and measures that are applicable to the different stages of production and various kiln types used in China: raw materials (and fuel) preparation; clinker making (applicable to all kilns, rotary kilns only, vertical shaft kilns only); and finish grinding; as well as plant wide measures and product and feedstock changes that will reduce energy consumption for clinker making. Table 1 lists all measures in this report by process to which they apply, including plant wide measures and product or feedstock changes. Tables 2 through 8 provide the following information for each technology: fuel and electricity savings per tonne of cement; annual operating and capital costs per tonne of cement or estimated payback period; and, carbon dioxide emissions reductions for each measure applied to the production of cement. This information was originally collected for a report on the U.S. cement industry (Worrell and Galitsky, 2004) and a report on opportunities for China's cement kilns (Price and Galitsky, in press). The information provided in

  4. The survey of cement dermatitis among construction industry workers

    Directory of Open Access Journals (Sweden)

    Faride Sadeghian

    2007-01-01

    Full Text Available Introduction: Cement has long been known as a cause of both irritant and allergic contact dermatitis. However, there are little data relating to occupational skin diseases (OSD in the Iranian construction industry. The aim of this study is to evaluate the epidemiology of cement dermatitis among terrazzo and cement manufactory workers. Methods: This is cross-sectional descriptive study. In this study 50 cement manufact-ory workers in Shahroud and 150 terrazzo workers in Lordegan were interviewed through questionnaire. Questionnaire includes demographic characteristics and questions about present dermatitis, background eczema, daily work hours, exposed chemical agents, using of gloves. Patients examined and patch tested by dermatologist. Data analyzed with SPSS software and c2, Mann Whitney and logistic regression statistical test. Results: The findings of the study showed that 8 workers (16% in cement factories and 52 workers (34.7% in Lordegan terrazzo enterprises had reported dermatitis at the time of review. Of which 15.5% in terrazzo workers had allergic contact dermatitis. In this study the prevalence of cement dermatitis increased with increasing age and there was significantly differences between dermatitis and background of dermatitis in terrazzo workers (P<0.05. Conclusion: Cement should be treated as hazardous materials, wearing of suitable gloves, early diagnosis and treatment of contact dermatitis and health education to workers is suggested.

  5. Development of Bulk Nanocrystalline Cemented Tungsten Carbide for Industrial Applicaitons

    Energy Technology Data Exchange (ETDEWEB)

    Z. Zak Fang, H. Y. Sohn

    2009-03-10

    This report contains detailed information of the research program entitled "Development of Bulk Nanocrystalline Cemented Tungsten Carbide Materials for Industrial Applications". The report include the processes that were developed for producing nanosized WC/Co composite powders, and an ultrahigh pressure rapid hot consolidation process for sintering of nanosized powders. The mechanical properties of consolidated materials using the nanosized powders are also reported.

  6. Industrial trial to produce a low clinker, low carbon cement

    Directory of Open Access Journals (Sweden)

    Vizcaíno-Andrés, L. M.

    2015-03-01

    Full Text Available A preliminary assessment of conditions for the industrial manufacture of a new cementitious system based on clinker-calcined clay and limestone, developed by the authors, referred as “low carbon cement” is presented. The new cement enables the substitution of more than 50% of the mass of clinker without compromising performance. The paper presents the follow-up of an industrial trial carried out in Cuba to produce 130 tonnes of the new cement at a cement plant. The new material proved to fulfill national standards in applications such as the manufacture of hollow concrete blocks and precast concrete. No major differences either in the rheological or mechanical properties were found when compared with Portland cement. Environmental assessment of the ternary cement was made, which included comparison with other blended cements produced industrially in Cuba. The new cement has proven to contribute to the reduction of above 30% of carbon emissions on cement manufacture.Se presenta la evaluación preliminar de las condiciones de fabricación industrial de un nuevo sistema cementicio a partir del empleo de clínquer; arcillas calcinadas y piedra caliza; desarrollado por los autores; denominado “cemento de bajo carbono”. El nuevo cemento posibilita la reducción de más de un 50% de la masa de clínquer; sin comprometer el comportamiento del material. El presente trabajo presenta el monitoreo de la producción industrial en una planta en Cuba; de 130 t del nuevo cemento. El cemento obtenido cumple con las regulaciones nacionales de calidad y su empleo tiene similar rendimiento que el cemento Pórtland para la producción de bloques y hormigón de 25 MPa. Se realiza el análisis de impacto ambiental del cemento ternario mediante la comparación con otros cementos producidos industrialmente. El nuevo cemento puede contribuir a la reducción de más del 30% de las emisiones de CO2 asociadas a la manufactura de cemento.

  7. Polish cement industry cartel - preliminary examination of collusion existence

    Directory of Open Access Journals (Sweden)

    Sylwester Bejger

    2011-01-01

    Full Text Available The paper is devoted to a case of a cartel in Polish cement industry. Short description of the industry and characteristics of the cartel with its fundamental illegal practices, market sharing and price fixing, have been done. We focused on examination of possibility of detection of a cartel-like behavior of players in an industry on a basis of cartel markers' evaluation, using statistical data we can actually obtain. On a basis of examination of market shares of players and price/supply processes we found distinctive, theoretically motivated patterns characteristic for collusive equilibrium in an industry.

  8. Effect of cement industry pollution on chlorophyll content of some crops at Kodinar, Gujarat, India

    OpenAIRE

    2013-01-01

    Study was carried out to assess the impact of cement industry pollution on some selected plant species around cement industry. Effect of cement dust on chlorophyll was studied in Arachis hypogaea, Sesamum indicum and Triticum species. Sampling was done at different distance like 0.5 km, 1.0 km and 2.0 km from the cement industry. The Chlorophyll pigments were reduced in dust-exposed plant species compared with control site Pransli (15 km away from the cement industry). Changes in chlorophyll ...

  9. Guidebook for Using the Tool BEST Cement: Benchmarking and Energy Savings Tool for the Cement Industry

    Energy Technology Data Exchange (ETDEWEB)

    Galitsky, Christina; Price, Lynn; Zhou, Nan; Fuqiu , Zhou; Huawen, Xiong; Xuemin, Zeng; Lan, Wang

    2008-07-30

    The Benchmarking and Energy Savings Tool (BEST) Cement is a process-based tool based on commercially available efficiency technologies used anywhere in the world applicable to the cement industry. This version has been designed for use in China. No actual cement facility with every single efficiency measure included in the benchmark will likely exist; however, the benchmark sets a reasonable standard by which to compare for plants striving to be the best. The energy consumption of the benchmark facility differs due to differences in processing at a given cement facility. The tool accounts for most of these variables and allows the user to adapt the model to operational variables specific for his/her cement facility. Figure 1 shows the boundaries included in a plant modeled by BEST Cement. In order to model the benchmark, i.e., the most energy efficient cement facility, so that it represents a facility similar to the user's cement facility, the user is first required to input production variables in the input sheet (see Section 6 for more information on how to input variables). These variables allow the tool to estimate a benchmark facility that is similar to the user's cement plant, giving a better picture of the potential for that particular facility, rather than benchmarking against a generic one. The input variables required include the following: (1) the amount of raw materials used in tonnes per year (limestone, gypsum, clay minerals, iron ore, blast furnace slag, fly ash, slag from other industries, natural pozzolans, limestone powder (used post-clinker stage), municipal wastes and others); the amount of raw materials that are preblended (prehomogenized and proportioned) and crushed (in tonnes per year); (2) the amount of additives that are dried and ground (in tonnes per year); (3) the production of clinker (in tonnes per year) from each kiln by kiln type; (4) the amount of raw materials, coal and clinker that is ground by mill type (in tonnes per

  10. Improving the CO2 performance of cement, part II : Framework for assessing CO2 improvement measures in cement industry

    OpenAIRE

    2015-01-01

    Cement production is among the largest anthropogenic sources of carbon dioxide (CO2) and there is considerable pressure on the cement industry to reduce these emissions. In the effort to reduce CO2 emissions, there is a need for methods to systematically identify, classify and assess different improvement measures, to increase the knowledge about different options and prioritize between them. For this purpose a framework for assessment has been developed, inspired by common approaches within ...

  11. Combustion of Sewage Sludge as Alternative Fuel for Cement Industry

    Institute of Scientific and Technical Information of China (English)

    LI Fuzhou; ZHANG Wei

    2011-01-01

    The combustion of sewage sludge and coal was studied by thermogravimetric analysis.Both differential scanning calorimetric analysis and derivative thermogravimetric profiles showed differences between combustion of sewage sludge and coal, and non-isothermal kinetics analysis method was applied to evaluate the combustion process. Based on Coats-Redfem integral method, some reaction models were tested,the mechanism and kinetics of the combustion reaction were discussed. The results show that the combustion of sewage sludge is mainly in the Iow temperature stage, meanwhile the ignition temperature and Arrhenius activation energy are lower than that of coal. The combustion of sewage sludge has the advantage over coal in some aspects, thus sewage sludge can partly replace coal used as cement industry fuel.

  12. Screening for collusion: Evidences from the Indian cement industry

    Directory of Open Access Journals (Sweden)

    Sylwester Bejger

    2015-07-01

    Full Text Available The paper is devoted to evaluation of the econometric method applied as a part of a variance screen in collusion detection procedure. Validation is based on ex-post analysis of Indian cement industry in the 1994 - 2009 time period and comparative study of the obtained results with factual evidences of collusion at that market. The method in question is based on MS(MAR (p, q Markov switching model specification. As a result of the research we could identify variability regimes consistent with theoretical motivation of the marker and detect collusion and competition phases partly consistent with historical evidences. However promising, method had some drawbacks applied to high frequency data in the context of variance screen. We proposed some solutions for further research to overcome it.

  13. Cement Conundrum

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    China aims to streamline the crowded cement industry Policymakers are looking to build a concrete wall around the cement-making industry as they seek to solidify the fluid cement market and cut excessive production.

  14. Present Situation and Perspective of Chinese Cement Industry

    Institute of Scientific and Technical Information of China (English)

    Gao Changming

    2003-01-01

    @@ Totally, there are 12 types of cement kiln pro-duction lines in China and running with a quite differenttechnical- economical levels. The cement productionof different types product lines in 1997 ~ 2002 is shownin Table 1.

  15. A study on respiratory problems and pulmonary function indexes among cement industry workers in Mashhad, Iran

    OpenAIRE

    Ehsan Rafeemanesh; Ashkan Alizadeh; Lahya Afshari Saleh; Hosein Zakeri

    2015-01-01

    Background: The respiratory system is the most vulnerable system in the cement industry. This study was conducted to determine the effects of occupational exposure to cement dust on the respiratory system more thoroughly. Material and Methods: In this cross sectional study an interviewer-administered questionnaire on socio-demographic characteristics and respiratory symptoms was completed and pulmonary function tests were carried out on 100 exposed and 120 non-exposed workers at the cement fa...

  16. Toward a sustainable cement industry in 2020 : improvement of the environmental, health & safety performance

    NARCIS (Netherlands)

    2001-01-01

    This background document concentrates on technical and managerial aspects of Environmental, Health & Safety Performance (EHS) control in the cement industry. It gives an overview of options for improvement toward a sustainable cement production in 2020. Energy consumption and use of alternative fuel

  17. Opportunities for Energy Efficiency and Demand Response in the California Cement Industry

    Energy Technology Data Exchange (ETDEWEB)

    Olsen, Daniel; Goli, Sasank; Faulkner, David; McKane, Aimee

    2010-12-22

    This study examines the characteristics of cement plants and their ability to shed or shift load to participate in demand response (DR). Relevant factors investigated include the various equipment and processes used to make cement, the operational limitations cement plants are subject to, and the quantities and sources of energy used in the cement-making process. Opportunities for energy efficiency improvements are also reviewed. The results suggest that cement plants are good candidates for DR participation. The cement industry consumes over 400 trillion Btu of energy annually in the United States, and consumes over 150 MW of electricity in California alone. The chemical reactions required to make cement occur only in the cement kiln, and intermediate products are routinely stored between processing stages without negative effects. Cement plants also operate continuously for months at a time between shutdowns, allowing flexibility in operational scheduling. In addition, several examples of cement plants altering their electricity consumption based on utility incentives are discussed. Further study is needed to determine the practical potential for automated demand response (Auto-DR) and to investigate the magnitude and shape of achievable sheds and shifts.

  18. Obtaining a sulfoaluminate belite cement by industrial waste

    Directory of Open Access Journals (Sweden)

    Elkhadiri, L.

    2003-06-01

    Full Text Available Sulfoaluminate belite clinkers by burning raw at moderate temperatures near 1250 °C were synthesized. The used mixtures were made by calcium carbonate blended to two industrial wastes: low calcium fly ash and phosphogypsum. The clinkers were characterised by X-Ray Diffraction (XRD, Infrared Spectroscopy (FTIR and free lime. The hydraulic behaviour of the obtained cements, by adequate clinkers with 7% of added gypsum, was followed by XRD, scaning electronic microscopy (SEM, FTIR and NMR.

    Los clínkeres belíticos de sulfoaluminatos se obtienen por cocción de crudos a temperaturas moderadas, hacia 1.250 ºC. Esos crudos se componen de carbonato de calcio mezclados con dos subproductos industriales: cenizas volantes pobres en óxido de calcio y fosfoyeso. Los clínkeres obtenidos se caracterizaron a través de Difracción de Rayos X (DRX, Espectroscopia Infrarroja por Transformada de Fourier (FTIR y por la determinación de CaO libre. El comportamiento hidráulico de los cementos elaborados de los clínkeres con el 7% de yeso se estudió por DRX, Microscopía Electrónica de Barrido (SEM, FTIR y Resonancia Magnética Nuclear (RMN

  19. Industrial transformation and green production to reduce environmental emissions:Taking cement industry as a case

    Institute of Scientific and Technical Information of China (English)

    LU¨ Yong-Long; GENG Jing; HE Gui-Zhen

    2015-01-01

    Industrial transformation and green production (ITGP) is a new 10-year international research initiative proposed by the Chinese National Committee for Future Earth. It is also an important theme for adapting and responding to global environmental change. Aiming at a thorough examination of the implementation of ITGP in China, this paper presents its objectives, its three major areas, and their progress so far. It also identifies the key elements of its management and proposes new perspectives on managing green transformation. For instance, we introduce a case study on cement industry that shows the positive policy effects of reducing backward production capacity on PCDD/Fs emissions. Finally, to develop different transformation scenarios for a green future, we propose four strategies:1) policy integration for promoting green industry, 2) system innovation and a multidisciplinary approach, 3) collaborative governance with all potential stakeholders, and 4) managing uncertainty, risks, and long-time horizons.

  20. Technology Roadmap: Low-Carbon Technology for the Indian Cement Industry

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2013-06-01

    The Indian cement industry is one of the most efficient in the world. Its efforts to reduce its carbon footprint by adopting the best available technologies and environmental practices are reflected in the achievement of reducing total CO2 emissions to an industrial average of 0.719 tCO2/t cement in 2010 from a substantially higher level of 1.12 tCO2/t cement in 1996. However, because the manufacturing process relies on the burning of limestone, it still produced 137 MtCO2 in 2010 – approximately 7% of India’s total man-made CO2 emissions. Yet opportunity for improvement exists, particularly in relation to five key levers that can contribute to emissions reductions: alternative fuel and raw materials; energy efficiency; clinker substitution; waste heat recovery and newer technologies. This roadmap sets out one pathway by which the Indian cement industry can reach its targets to improve energy efficiency and reduce CO2 emissions by 2050, thereby laying the foundation for low-carbon growth in the years beyond. The Technology Roadmap: Low-Carbon Technology for the Indian Cement Industry builds on the global IEA technology roadmap for the cement sector developed by the IEA and the World Business Council for Sustainable Development’s Cement Sustainability Initiative. It outlines a possible transition path for the Indian cement industry to reduce its direct CO2 emissions intensity to 0.35 tCO2/t cement and support the global goal of halving CO2 emissions by 2050.

  1. Analysis of Energy-Efficiency Opportunities for the Cement Industry in Shandong Province, China

    Energy Technology Data Exchange (ETDEWEB)

    Price, Lynn; Hasanbeigi, Ali; Lu, Hongyou; Wang, Lan

    2009-10-01

    China's cement industry, which produced 1,388 million metric tons (Mt) of cement in 2008, accounts for almost half of the world's total cement production. Nearly 40% of China's cement production is from relatively obsolete vertical shaft kiln (VSK) cement plants, with the remainder from more modern rotary kiln cement plants, including plants equipped with new suspension pre-heater and pre-calciner (NSP) kilns. Shandong Province is the largest cement-producing Province in China, producing 10% of China's total cement output in 2008. This report documents an analysis of the potential to improve the energy efficiency of NSP kiln cement plants in Shandong Province. Sixteen NSP kiln cement plants were surveyed regarding their cement production, energy consumption, and current adoption of 34 energy-efficient technologies and measures. Plant energy use was compared to both domestic (Chinese) and international best practice using the Benchmarking and Energy Saving Tool for Cement (BEST-Cement). This benchmarking exercise indicated an average technical potential primary energy savings of 12% would be possible if the surveyed plants operated at domestic best practice levels in terms of energy use per ton of cement produced. Average technical potential primary energy savings of 23% would be realized if the plants operated at international best practice levels. Energy conservation supply curves for both fuel and electricity savings were then constructed for the 16 surveyed plants. Using the bottom-up electricity conservation supply curve model, the cost-effective electricity efficiency potential for the studied cement plants in 2008 is estimated to be 373 gigawatt hours (GWh), which accounts for 16% of total electricity use in the 16 surveyed cement plants in 2008. Total technical electricity-saving potential is 915 GWh, which accounts for 40% of total electricity use in the studied plants in 2008. The fuel conservation supply curve model shows the total

  2. Cement industry control system based on multi agent

    Institute of Scientific and Technical Information of China (English)

    王海东; 邱冠周; 黄圣生

    2004-01-01

    Cement production is characterized by its great capacity, long-time delay, multi variables, difficult measurement and muhi disturbances. According to the distributed intelligent control strategy based on the multi agent, the multi agent control system of cement production is built, which includes integrated optimal control and diagnosis control. The distributed and multiple level structure of multi agent system for the cement control is studied. The optimal agent is in the distributed state, which aims at the partial process of the cement production, and forms the optimal layer. The diagnosis agent located on the diagnosis layer is the diagnosis unit which aims at the whole process of the cement production, and the central management unit of the system. The system cooperation is realized by the communication among optimal agents and diagnosis agent. The architecture of the optimal agent and the diagnosis agent are designed. The detailed functions of the optimal agent and the diagnosis agent are analyzed.At last the realization methods of the agents are given, and the application of the multi agent control system is presented. The multi agent system has been successfully applied to the off-line control of one cement plant with capacity of 5 000 t/d. The results show that the average yield of the clinker increases 9.3% and the coal consumption decreases 7.5 kg/t.

  3. Reduction of Multi-pollutant Emissions from Industrial Sectors: The U.S. Cement Industry – A Case Study

    Science.gov (United States)

    For Frank Princiotta’s book, Global Climate Change—The Technology Challenge Carbon dioxide (CO2) accounts for more than 90% of worldwide CO2-eq green-house gas (GHG) emissions from industrial sectors other than power generation. Amongst these sectors, the cement industry is one ...

  4. CO2 REDUCTION OPTIONS IN CEMENT INDUSTRY - THE NOVI POPOVAC CASE

    Directory of Open Access Journals (Sweden)

    Gordana M Stefanović

    2010-01-01

    Full Text Available The cement industry contributes about 5% to global anthropogenic CO2 emissions, and is thus an important sector in CO2-emission mitigation strategies. Carbon dioxide is emitted from the calcination process of limestone, from combustion of fuels in the kiln, and from the coal combustion during power generation. Strategies to reduce these CO2 emissions include energy efficiency improvement, new processes, shift to low carbon fuels or waste fuels in cement production, increased use of additives in cement production, alternative cements, and CO2 removal from flue gases in clinker kilns. Increased use of fly ash as an additive to cement and concrete has a number of advantages, the primary being reduction of costs of fly ash disposal, resource conservation, and cost reduction of the product. Since the production of cement requires a large amount of energy (about 2.9-3.2 GJt-1, the substitution of cement by fly ash saves not only energy but also reduces the associated greenhouse gas emissions. The paper evaluates the reduction of CO2 emissions that can be achieved by these mitigation strategies, as well as by partial substitution of cement by fly ash. The latter is important because the quality of the produced concrete depends on the physical-chemical properties of the fly ash and thus partial substitution as well as the type of fly ash (e.g., the content of CaO has an effect not only on energy consumption and emissions, but also on the produced concrete quality.

  5. CEMENT. "A Concrete Experience." A Curriculum Developed for the Cement Industry.

    Science.gov (United States)

    Taylor, Mary Lou

    This instructor's guide contains 11 lesson plans for inplant classes on workplace skills for employees in a cement plant. The 11 units cover the following topics: goals; interpreting memoranda; applying a standard set of work procedures; qualities of a safe worker; accident prevention; insurance forms; vocabulary development; inventory control…

  6. Energy efficiency and carbon dioxide emissions reduction opportunities in the U.S. cement industry

    Energy Technology Data Exchange (ETDEWEB)

    Martin, Nathan; Worrell, Ernst; Price, Lynn

    1999-08-01

    This paper reports on an in-depth analysis of the U.S. cement industry, identifying cost-effective energy efficiency measures and potentials. The authors assess this industry at the aggregate level (Standard Industrial Classification 324), which includes establishments engaged in manufacturing hydraulic cements, including Portland, natural, masonry, and pozzolana when reviewing industry trends and when making international comparisons. Coal and coke are currently the primary fuels for the sector, supplanting the dominance of natural gas in the 1970s. Between 1970 and 1997, primary physical energy intensity for cement production (SIC 324) dropped 30%,from 7.9 GJ/t to 5.6 GJ/t, while carbon dioxide intensity due to fuel consumption (carbon dioxide emissions expressed in tons of carbon per ton cement) dropped 25%, from 0.16 tC/ton to 0.12 tC/ton. Carbon dioxide intensity due to fuel consumption and clinker calcination dropped 17%, from 0.29 tC/ton to 0.24 tC/ton. They examined 30 energy efficient technologies and measures and estimated energy savings, carbon dioxide savings, investment costs, and operation and maintenance costs for each of the measures. They constructed an energy conservation supply curve for U.S. cement industry which found a total cost-effective reduction of 0.6 GJ/ton of cement consisting of measures having a simple payback period of 3 years or less. This is equivalent to potential energy savings of 11% of 1994 energy use for cement making and a savings of 5% of total 1994 carbon dioxide emissions by the U.S. cement industry. Assuming the increased production of blended cement in the U.S., as is common in many parts of the world, the technical potential for energy efficiency improvement would not change considerably. However, the cost-effective potential, would increase to 1.1 GJ/ton cement or 18% of total energy use, and carbon dioxide emissions would be reduced by 16%.

  7. Oxygen transport membranes for biomass gasification and cement industry

    DEFF Research Database (Denmark)

    Cheng, Shiyang

    Oxygen transport membranes (OTMs) are of particular interest for their potential applications in high purity oxygen separation, biomass gasification and carbon capture and storage in cement production. Gd0.1Ce0.9O1.95-δ (GCO) is one of the interesting materials of OTMs because of its high ionic...

  8. Recent developments in the cement industry: a comparative study between Mexico and India

    Directory of Open Access Journals (Sweden)

    Ganesh Babu Kumaran

    2008-10-01

    Full Text Available Since early twentieth century, the use of cement has become a popular and strategic product for economic growth of every country. In India as in Mexico, the first factories began in the earlier twentieth century, India is nowadays the world’s second largest producer and Mexico is the third firm in cement production, despite being the tenth world producer. The eighties have significate for both countries major structural changes in its economy, which have radically altered the structure and functioning of the cement industry and even more during the decade of the nineties. This article discusses the recent performance of the cement industry in both countries, compares the dynamics and causes that gave rise to these changes. It examines changes in the structure of domestic market in both countries and the strategies employed by large companies that operate in both, including a brief analysis of the role of transnational corporations in their development at the stage of globalization and liberalization of markets that characterizes the last two decades. Finally, it explores the great changes that make possible the growth and expansion of the cement industry during the period, based on technological change, the determinants of competitiveness and the role of economic policies in the development of industry in both countries.

  9. Blended Cements Produced With Synthetic Zeolite Made from Industrial By-Product

    Directory of Open Access Journals (Sweden)

    Vitoldas Vaitkevičius

    2015-03-01

    Full Text Available Zeolites are appropriate supplementary cementitious materials in cement and concrete industry. In the present work synthetic zeolites was used like supplementary material in hardened cement paste and some properties as well as its influence on Portland cement hydration was determinate. X-ray powder diffraction, scanning electronic microscopy and energy-dispersive X-ray spectroscopy, FTIR spectroscopy were used as investigation methods. The compressive strength of hardened cement paste was measured at day 3, 28 and 60. The instrumental analysis showed that zeolite A(Na dominates and unreacted Al(OH3 remains in investigated synthetics zeolites, made from thermal and mechanical treated AlF3 production waste. The Chapelle test showed that both zeolites have good pozzolanic properties. The samples compressive strength remained close to the control samples compressive strength, reducing the amount of Portland cement, i.e., changing it by zeolite. After 60 days, the compressive strength was the best in the samples where 5% of Portland cement was replaced by the 2-zeolite. The compressive strength of the samples increased by 9 % compared with control samples. This research provides a real opportunity to save cement thus disposing the waste.DOI: http://dx.doi.org/10.5755/j01.ms.21.1.5635

  10. Feasibility study of the Portland cement industry waste for the reduction of energy consumption

    Energy Technology Data Exchange (ETDEWEB)

    Bernardo, Ana Carla de Souza Masselli; Junqueira, Mateus Augusto F. Chaib; Jorge, Ariosto Bretanha; Silva, Rogerio Jose da [Universidade Federal de Itajuba (UNIFEI), MG (Brazil). Institute of Mechanical Engineering]. E-mails: anacarlasz@unifei.edu.br; mateus_afcj@yahoo.com.br; ariosto.b.jorge@unifei.edu.br; rogeriojs@unifei.edu.br

    2008-07-01

    The Portland cement industry demand a high specific consumption of energy for the production of the clinker. The energy consumption for clinker production varies between 3000 and 5300 kJ/kg of produced clinker. The clinker is produced by blending of different raw materials in order t o achieve precise chemical proportions of lime, silica, alumina and iron in the finished product and by burning them at high temperatures. The Portland cement is a mixture of clinker, gypsum and other materials. Due to need of high temperatures, tradition ally the fuels used in the cement industry are mineral coal, fuel oil, natural gas and petroleum coke. The fuel burning in high temperature leads to the formation of the pollutant thermal NOx. The level of emissions of this pollutant is controlled by environmental law, thus the formation of pollutants in process need be controlled. Moreover, industrial waste has been used by Portland cement industries as a secondary fuel through a technique called co -processing. Materials like waste oils, plastics, waste tyres and sewage sludge are often proposed as alternative fuels for the cement industry. The residues can be introduced as secondary fuel or secondary raw material. For energy conservation in the process, mineralizers are added during the process production of the clinker. The mineralizers promote certain reactions which decrease the temperature in the kiln and improve the quality of the clinker. The adequate quantity of constituents in production process is complex, for maintain in controlled level, the quality of final product, the operational conditions of kiln, and the pollutant emissions. The purpose of the present work is to provide an analysis of an optimal production point through of the optimization technique considering, the introduction of the fuels, industrial wastes as secondary fuels, and raw materials, for the reduction of energy in the process of Portland cement production. (author)

  11. Accelerated weathering of limestone for CO2 mitigation: Opportunities for the stone and cement industries

    Science.gov (United States)

    Langer, William H.; San, Juan A.; Rau, Greg H.; Caldeira, Ken

    2009-01-01

    Accelerated weathering of limestone appears to provide a low-tech, inexpensive, high-capacity, environmentally friendly CO2 mitigation method that could be applied to about 200 fossil fuel fired power plants and about eight cement plants located in coastal areas in the conterminous U.S. This approach could also help solve the problem of disposal of limestone waste fines in the crushed stone industry. Research and implementation of this technology will require new collaborative efforts among the crushed stone and cement industries, electric utilities, and the science and engineering communities.

  12. HYDRATION AND PROPERTIES OF BLENDED CEMENT SYSTEMS INCORPORATING INDUSTRIAL WASTES

    Directory of Open Access Journals (Sweden)

    Heikal M.

    2013-06-01

    Full Text Available This paper aims to study the characteristics of ternary blended system, namely granulated blast-furnace slag (WCS, from iron steel company and Homra (GCB from Misr Brick (Helwan, Egypt and silica fume (SF at 30 mass % pozzolanas and 70 mass % OPC. The required water of standard consistency and setting times were measured as well as physico-chemical and mechanical characteristics of the hardened cement pastes were investigated. Some selected cement pastes were tested by TGA, DTA and FT-IR techniques to investigate the variation of hydrated products of blended cements. The pozzolanic activity of SF is higher than GCB and WCS. The higher activity of SF is mainly due to its higher surface area than the other two pozzolanic materials. On the other side, GCB is more pozzolanic than WCS due to GCB containing crystalline silica quartz in addition to an amorphous phase. The silica quartz acts as nucleating agents which accelerate the rate of hydration in addition to its amorphous phase, which can react with liberating Ca(OH2 forming additional hydration products.

  13. Modeling energy efficiency to improve air quality and health effects of China's cement industry

    NARCIS (Netherlands)

    Zhang, Shaohui; Worrell, Ernst; Crijns-Graus, Wina; Krol, Maarten; de Bruine, Marco; Geng, Guangpo; Wagner, Fabian; Cofala, Janusz

    2016-01-01

    Actions to reduce the combustion of fossil fuels often decrease GHG emissions as well as air pollutants and bring multiple benefits for improvement of energy efficiency, climate change, and air quality associated with human health benefits. The China's cement industry is the second largest energy co

  14. Policy Options for Encouraging Energy Efficiency Best Practices in Shandong Province's Cement Industry

    Energy Technology Data Exchange (ETDEWEB)

    Price, Lynn [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Zhou, Nan [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Lu, Hongyou [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Sambeek, Emiel van [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Yowargana, Ping [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Shuang, Liu [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Kejun, Jiang [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2012-07-12

    This research intends to explore possible design options for a sectoral approach in the cement sector in Shandong Province and to consider its respective advantages and disadvantages for future application. An effort has been made in this research to gather and analyze data that will provide a transparent and robust basis for development of a Business-As-Usual (BAU) scenario, maximum technology potential scenario, and ultimately a sector crediting baseline. Surveys among cement companies and discussions with stakeholders were also conducted in order to better understand the industry and local needs related to the sectoral approach.

  15. Factor ten emission reductions : the key to sustainable development and economic prosperity for the cement and concrete industry

    Energy Technology Data Exchange (ETDEWEB)

    Horton, R. [Alchemix Corp., Pittsburgh, PA (United States)

    2001-07-01

    This paper proposes that the negative environmental effects of current cement/concrete production can be reduced by a factor of 10 by using cement blends with minimum portland cement and maximum pozzolanic loading. In addition to extending the longevity of concrete, such cement blends also avoid the huge cost of repairs and replacement cycles. Market forces will drive this transition toward sustainable development in the concrete and cement industry. The economic advantages of improving the quality of the concrete are great. Even if improving the concrete doubles the price of the highest quality cement, this would only add 2 per cent to the cost of the overall construction project, but the service life of the structure would give a many-fold return on this added investment. Also, regulations on carbon dioxide emissions in the near future will assume economic importance in the manufacturing of cement and concrete. While portland cements have dominated the construction industry for more than 150 years, new blended cements priced on a performance basis will become the standard in the twenty first century. Currently, the typical cement formulation in the United States, if it contains fly ash, contains 15 to 20 per cent fly ash by weight of the total cementitious material. This paper states that soon the number will be 50 to 60 per cent ash. Fly ash will be widely acknowledged for improving critical performance characteristics of concrete such as workability, impermeability and durability. Carbon dioxide credits will also be a major economic factor that will drive the cement industry toward a factor ten environmental improvement. The Kyoto Protocol calls for the trading of greenhouse gas credits which includes carbon dioxide credits. Under the new system, cement producers will be taxed on excess emissions, while those using pozzolans in their cements will earn credits to offset these penalties. 10 refs.

  16. A study on respiratory problems and pulmonary function indexes among cement industry workers in Mashhad, Iran

    Directory of Open Access Journals (Sweden)

    Ehsan Rafeemanesh

    2015-08-01

    Full Text Available Background: The respiratory system is the most vulnerable system in the cement industry. This study was conducted to determine the effects of occupational exposure to cement dust on the respiratory system more thoroughly. Material and Methods: In this cross sectional study an interviewer-administered questionnaire on socio-demographic characteristics and respiratory symptoms was completed and pulmonary function tests were carried out on 100 exposed and 120 non-exposed workers at the cement factory in Mashhad, Iran. The data was statistically analyzed by SPSS 16. Results: The mean of age and work duration in the exposed group was 37.5±6.3 and 10.7±5.4 years compared with the non-exposed group that was 36.1±7.1 and 10.1±5.7 years, respectively. Levels of exposure to inhalable cement dust in the exposed group were 23.13 mg/m3 (higher than national occupational exposure limits for such particles. Among the exposed group, respiratory symptoms as cough (6% vs. 0.8% of the non-exposed and sputum (7% vs. 0.8% of the nonexposed were significantly more prevalent (p < 0.05. Forced expiratory flow 25–75% (FEF25–75% was significantly lower in the exposed workers compared with non-exposed ones (p < 0.05. Also forced expiratory volume in 1 s / forced vital capacity (FEV1/FVC and FEF25–75% had a reverse correlation with the length of employment (p = 0.000 and p = 0.003, respectively. Conclusions: The findings of this study showed that occupational exposure to cement dust could be a significant factor of respiratory system dysfunction. Strict implementation of a respiratory protection program is recommended in cement industries. Med Pr 2015;66(4:471–477

  17. X-ray powder diffractometry of emissions from the cement industry

    Science.gov (United States)

    Parekh, P. P.; Khan, A. R.; Davin, M. T.

    X-ray powder diffractometry has been found capable of identifying and distinguishing limestone and cement particles, the two important emissions of the cement industry. The limestone shows strong reflections principally at 1.87,1.91,2.09,2.28,2.49,3.03 and 3.83 Å from its main constituent, calcite, whereas cement shows reflections at 1.76, 2.18, 2.60, 2.64, a doublet at 2.73-2.77 and 3.02 Å from its main phases, the di-, and tri-calcium silicates. X-ray diffraction analysis of airborne particles collected on glass fibre filters in the vicinity of cement factories in Karachi, Pakistan and Ravena, New York State, revealed limestone but no cement particles. This observation was consistent with our earlier inference drawn from chemical and statistical methods for Karachi's ambient aerosols. The method can complement the selective leaching technique suggested earlier by us for source identification. On the basis of model calculations, a methodology has been worked out that would make the present technique adaptable to plant conditions.

  18. Assessment of air pollution tolerance levels of selected plants around cement industry, Coimbatore, India.

    Science.gov (United States)

    Radhapriya, P; NavaneethaGopalakrishnan, A; Malini, P; Ramachandran, A

    2012-05-01

    Being the second largest manufacturing industry in India, cement industry is one of the major contributors of suspended particulate matter (SPM). Since plants are sensitive to air pollution, introducing suitable plant species as part of the greenbelt around cement industry was the objective of the present study. Suitable plant species were selected based on the Air pollution tolerance index (APTI) calculated by analyzing ascorbic acid (AA), pH, relative water content (RWC) and total chlorophyll (TChl) of the plants occuring in the locality. Plants were selected within a 6 km radius from the industry and were graded as per their tolerance levels by analyzing the biochemical parameters. From the statistical analysis at 0.05 level of significance a difference in the APTI values among the 27 plant species was observed, but they showed homogenous results when analysed zone wise using one-way analyses of variance. Analyses of individual parameters showed variation in the different zones surrounding the cement industry, whereas the APTI value (which is a combination of the parameter viz. AA, RWC, TChl, pH) showed more or less same gradation. Significant variation in individual parameters and APTI was seen with in the species. All the plants surrounding the cement industry are indicative of high pollution exposure comparable to the results obtain for control plants. Based on the APTI value, it was observed that about 37% of the plant species were tolerant. Among them Mangifera indica, Bougainvillea species, Psidum quajava showed high APTI values. 33% of the species were highly susceptible to the adverse effects of SPM, among which Thevetia neriifolia, Saraca indica, Phyllanthus emblica and Cercocarpus ledifolius showed low APTI values. 15% each of the species were at the intermediary and moderate tolerance levels.

  19. New trends in the treatment of meat industry waste waters; Depuracion de aguas residuales de la industria carnica. Nueva tendencias

    Energy Technology Data Exchange (ETDEWEB)

    Diez, V.; Pozo, R. del [Universidad de Burgos. Burgos (Spain)

    2000-07-01

    In this work, several alternatives for the meat industry wastewater treatment are examined. It is also presented the way in which the new technologies are being applied to this sector, as well as the future tendencies in the development of treatment processes specially adapted for the meat industry. Authors expose which are the guidelines that, in their opinion, must rule the development of treatment systems based on the particular characteristics of this sector and the different troubles and limitations that came up when the new technologies have been applied to this kind of wastewater. (Author) 17 refs.

  20. Solid recovered fuels in the cement industry with special respect to hazardous waste.

    Science.gov (United States)

    Thomanetz, Erwin

    2012-04-01

    Cements with good technical properties have been produced in Europe since the nineteenth century and are now worldwide standardized high-quality mass products with enormous production numbers. The basic component for cement is the so-called clinker which is produced mainly from raw meal (limestone plus clay plus sands) in a rotary kiln with preheater and progressively with integrated calciner, at temperatures up to 1450 °C. This process requires large amounts of fossil fuels and is CO₂-intensive. But most CO₂ is released by lime decomposition during the burning process. In the 1980s the use of alternative fuels began--firstly in the form of used oil and waste tyres and then increasingly by pre-conditioned materials from commercial waste and from high calorific industrial waste (i.e. solid recovered fuel (SRF))--as well as organic hazardous waste materials such as solvents, pre-conditioned with sawdust. Therefore the cement industry is more and more a competitor in the waste-to-energy market--be it for municipal waste or for hazardous waste, especially concerning waste incineration, but also for other co-incineration plants. There are still no binding EU rules identifying which types of SRF or hazardous waste could be incinerated in cement kilns, but there are some well-made country-specific 'positive lists', for example in Switzerland and Austria. Thus, for proper planning in the cement industry as well as in the waste management field, waste disposal routes should be considered properly, in order to avoid surplus capacities on one side and shortage on the other.

  1. PROSPECTS OF THE ENVIRONMENTAL TECHNOLOGIES IMPLEMENTATION IN THE CEMENT INDUSTRY IN RUSSIA

    Directory of Open Access Journals (Sweden)

    Galina Peshkova

    2016-09-01

    Full Text Available Russian cement industry is in decline. Enterprises operate on the basis of technologies developed in USSR. In this connection such fundamental issues of the enterprises functioning, as energy efficiency, environmental safety, resource-saving, resources provision and others, are overlooked. The paper attempts to define the priorities of the Russian cement industry development based on the experience of developed countries. The most promising technologies for the designated key areas were described and their benefits and drawbacks were identified. Due to the major role of the raw resources in Russian economy, the issues of increasing the efficiency of cement plants, should be discussed with considering the efficiency of mining enterprises extracting mineral raw materials needed for manufacturing process. Given the significant investments required to the industry modernization, which can not be achieved through government support, it is proposed to create conditions for the development of the integrated companies. In addition, a key factor that can ensure the sustainable development of the industry is a cross-sectoral co-operation, which will allow to organize a low-waste production cycle with a minimal costs of raw materials.

  2. [Study on feasible emission control level of air pollutions for cement industry ].

    Science.gov (United States)

    Ren, Chun; Jiang, Mei; Zou, Lan; Li, Xiao-qian; Wei, Yu-xia; Zhao, Guo-hua; Zhang, Guo-ning

    2014-09-01

    The revised National Emission Standard of Air Pollutions for Cement Industry has been issued, which will be effective for the new enterprises and the existing enterprises on Mar. 1st, 2014 and July 1st, 2015, respectively. In the process of revision, the key technical issues on determination of standard limits was how to determine the feasible emission control level of air pollutions. Feasible emission control requirements were put forward, according to air pollutants emission, technologies, environmental management requirements and foreign standards, etc. The main contents of the revised standard include expanding the scope of application, increasing the pollutants, improving the particulate and NO emissions control level, and increasing special emission limits applied to key areas of air pollutants. The standard will become the gripper of pollution prevention, total emission reduction, structural adjustment and optimization of the layout, and will promote scientific and technical progression for the cement industry.

  3. QUANTIFICATION OF THE DECISIONS OF CONTROL AND AUDIT IN INVENTORY MANAGEMENT IN CEMENT INDUSTRY ENTERPRISES

    OpenAIRE

    Sylwia £êgowik-Œwi¹cik

    2011-01-01

    Inventory management in enterprises of cement industry necessitates the assessment of the level of risk which is generated by production inventory. The processes of control and auditing allow for planning, monitoring and organization of inventory management in the analysed business entities. This paper is aimed at presentation of the phase of preparation of audit activities in the area of inventory and verification of model solutions for the processes of control and audit in terms of inventor...

  4. THE INTERNAL FACTORS AFFECTING LUNG CAPACITY OF PEOPLE LIVING IN AREAS AROUND THE CEMENT INDUSTRY, INDONESIA

    Directory of Open Access Journals (Sweden)

    Erwin Azizi Jayadipraja

    2016-05-01

    Full Text Available Background: Some internal factors have both positive and negative effects to people’s health, especially those who live in a polluted area. The area around the cement industry is an example of polluted area in which the lung capacity will be harmed. Aim: This research aimed at finding out internal factors affecting lung capacity of people living in the area around the cement industry. Methods: This research used a cross sectional study plan by measuring lung capacity (FEV1 and FVC of people living in four different locations. The locations were based on wind directions and within 3 km from the cement industry. The study plan was also done by connecting the measurement with other factors, such as age, physical activities, nutrition status and passive smoking or environmental tobacco smoke (ETS. Results: Based on the calculation of lung capacity 241 respondents obtained 123 respondents (51% had a normal lung capacity, 105 respondents (43.6% had a restricted lung capacity, 4 respondents (1.7% had an obstructed lung capacity and 9 respondents (3.7% had a combination of a restricted and obstructed lung capacity. The age (p=0.977 and physical activities (p=0.087 of respondents had no effect on the lung capacity. However, nutrition status (p=0.011 and passive smoking or ETS (p=0.003 do. Conclusion: The nutrition status and the presence of a passive smoker were the internal factors affecting people’s lung capacity, especially for those who live around the cement industry. Thus, in order to avoid the impairment of lung capacity, people need to improve their nutrition and to avoid people smoking around them.

  5. Study of energy efficiency measures in cement industry; Estudo de medidas de eficiencia energetica na industria de cimento

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Roberta Ferreira Carrijo; Gorla, Filipe Debonzi [Universidade Estadual de Campinas (UNICAMP), SP (Brazil)

    2008-07-01

    Methods of energy conservation play an important role in the future energetic supply. The cement industry, being energetic intensive, is an important niche of performance of such methods. It is intended, in the present work, to estimate the impact of energy conservation through different scenarios. The projections have been realized considering both the technical (equipment efficiency) and economical (Industrial Transformation Worth - ITW) aspects of the cement sector. (author)

  6. Technical and cost assessment of energy efficiency improvement and greenhouse gas emission reduction potentials in Thai cement industry

    Energy Technology Data Exchange (ETDEWEB)

    Hasanbeigi, A. [The Joint Graduate School of Energy and Environment, King Mongkut' s University of Technology Thonburi, 126 Pracha-uthit Rd, Bangmod, Tungkru, Bangkok (Thailand); Menke, C. [Department of Building Engineering Services, Energy Technology Division, University of Applied Sciences, Schneidershof, 54293 Trier (Germany); Therdyothin, A. [The School of Energy, Environment, and Material, King Mongkut' s University of Technology Thonburi, Bangkok (Thailand)

    2011-01-15

    The cement industry is one of the most energy-consuming industries in Thailand, with high associated carbon dioxide (CO2) emissions. The cement sector accounted for about 20.6 million tonnes of CO2 emissions in 2005. The fuel intensity of the Thai cement industry was about 3.11 gigajoules (GJ)/tonne cement; the electricity intensity was about 94.3 kWh/tonne cement, and the total primary energy intensity was about 4.09 GJ/tonne cement in 2005 with the clinker to cement ratio of around 82%. In this study, the potential application of 47 energy-efficiency measures is assessed for the Thai cement industry. Using a bottom-up electricity conservation supply curve model, the cost-effective electricity efficiency improvement potential for the Thai cement industry is estimated to be about 265 gigawatt hours (GWh), which accounts for 8% of total electricity use in the cement industry in 2005. Total technical electricity-saving potential is 1,697 GWh, which accounts for 51% of total electricity use in the cement industry in 2005. The CO2 emission reduction potential associated with the cost-effective electricity savings is 159 kilotonne (kt) CO2, while the total technical potential for CO2 emission reductions is 902 ktonne CO2. The fuel conservation supply curve model shows a cost-effective fuel-efficiency improvement potential of 17,214 terajoules (TJ) and a total technical fuel efficiency improvement potential equal to 21,202 TJ, accounting for 16% and 19% of the total fuel use in the cement industry in 2005, respectively. CO2 emission reduction potentials associated with cost-effective and technical fuel-saving measures are 2,229 ktonne and 2,603 ktonne, respectively. Sensitivity analyses were conducted for discount rate, electricity and fuel prices, and exchange rate that showed the significant influence of these parameters on the results. Hence, the results of the study should be interpreted with caution.

  7. Critical elements in implementations of just-in-time management: empirical study of cement industry in Pakistan.

    Science.gov (United States)

    Qureshi, Muhammad Imran; Iftikhar, Mehwish; Bhatti, Mansoor Nazir; Shams, Tauqeer; Zaman, Khalid

    2013-01-01

    In recent years, inventory management is continuous challenge for all organizations not only due to heavy cost associated with inventory holding, but also it has a great deal to do with the organizations production process. Cement industry is a growing sector of Pakistan's economy which is now facing problems in capacity utilization of their plants. This study attempts to identify the key strategies for successful implementation of just-in-time (JIT) management philosophy on the cement industry of Pakistan. The study uses survey responses from four hundred operations' managers of cement industry in order to know about the advantages and benefits that cement industry have experienced by Just in time (JIT) adoption. The results show that implementing the quality, product design, inventory management, supply chain and production plans embodied through the JIT philosophy which infect enhances cement industry competitiveness in Pakistan. JIT implementation increases performance by lower level of inventory, reduced operations & inventory costs was reduced eliminates wastage from the processes and reduced unnecessary production which is a big challenge for the manufacturer who are trying to maintain the continuous flow processes. JIT implementation is a vital manufacturing strategy that reaches capacity utilization and minimizes the rate of defect in continuous flow processes. The study emphasize the need for top management commitment in order to incorporate the necessary changes that need to take place in cement industry so that JIT implementation can take place in an effective manner.

  8. Eco-efficiency of the world cement industry: A data envelopment analysis

    Energy Technology Data Exchange (ETDEWEB)

    Oggioni, G., E-mail: oggioni@eco.unibs.i [University of Brescia, Faculty of Economics, Department of Quantitative Methods, IT-25122 Brescia (Italy); Riccardi, R., E-mail: riccardi@ec.unipi.i [University of Brescia, Faculty of Economics, Department of Quantitative Methods, IT-25122 Brescia (Italy); Toninelli, R., E-mail: roberta.toninelli@unifi.i [University of Pisa, Faculty of Economics, Department of Statistics and Applied Mathematics, IT-56124 Pisa (Italy)

    2011-05-15

    Chemical reactions and the combustion of dirty fuels, such as coal and petroleum coke (petcoke), that are used in cement production processes generate a significant amount of CO{sub 2} emissions. In this paper, we provide an eco-efficiency measure for 21 prototypes of cement industries operating in many countries by applying both a data envelopment analysis (DEA) and a directional distance function approach, which are particularly suitable for models where several production inputs and desirable and undesirable outputs are taken into account. To understand whether this eco-efficiency is due to a rational utilization of inputs or to a real carbon dioxide reduction as a consequence of environmental regulation, we analyze the cases where CO{sub 2} emissions can either be considered as an input or as an undesirable output. Empirical results show that countries where cement industries invest in technologically advanced kilns and adopt alternative fuels and raw materials in their production processes are eco-efficient. This gives a comparative advantage to emerging countries, such as India and China, which are incentivized to modernize their production processes.

  9. Influence of Environmentally Friendly and High-Efficiency Composite Additives on Pulverized Coal Combustion in Cement Industry

    OpenAIRE

    2016-01-01

    4 kinds of chemical reagents and 3 kinds of industrial wastes were selected as burning additives for 2 kinds of coals in cement industry. The work focused on the replacement of partial chemical reagents by industrial wastes, which not only reduced the cost and took full advantage of industrial wastes, but also guaranteed the high combustion efficiency and removed the NOX and SO2 simultaneously. The experiments were carried out in DTF. The combustion residues were analyzed by SEM and XRD. The ...

  10. Biomonitoring spatial and temporal impact of atmospheric dust from a cement industry

    Energy Technology Data Exchange (ETDEWEB)

    Branquinho, Cristina [Universidade de Lisboa, Faculdade de Ciencias, Centro de Ecologia e Biologia Vegetal, Campo Grande, Edificio C2, Piso 4, 1749-016 Lisbon (Portugal); Universidade Atlantica, Antiga Fabrica da Polvora de Barcarena, 2745-615 Barcarena (Portugal)], E-mail: cmbranquinho@fc.ul.pt; Gaio-Oliveira, Gisela; Augusto, Sofia; Pinho, Pedro; Maguas, Cristina; Correia, Otilia [Universidade de Lisboa, Faculdade de Ciencias, Centro de Ecologia e Biologia Vegetal, Campo Grande, Edificio C2, Piso 4, 1749-016 Lisbon (Portugal)

    2008-01-15

    The objective of this work was to evaluate the spatial and temporal impact of dust-pollution in the vicinity of a cement industry, located in an area with dry climate. The spatial impact integrated over time was evaluated from the concentrations of Ca, Fe and Mg in in-situ Xanthoria parietina. The temporal pattern was assessed through one-month transplants of the lichen Ramalina canariensis. Four potential sources of atmospheric dust were evaluated: the limestone-quarry; the unpaved roads, the deposit area and the cement mill. Calcium concentration in lichens was considered the best cement-dust indicator. Different types of dust (clinker and grinded-limestone-dust) resulted in different time-patterns of Ca accumulation, which was also related with the different influence that wet and dry periods have in the lichen accumulation process. The dust pollution was found to be deposited locally and dependent on: the nature of dust particles and the volume and frequency of precipitation. - Biomonitoring Spatial and Temporal dust emissions in dry climates.

  11. Environmental impact of incineration of calorific industrial waste: rotary kiln vs. cement kiln.

    Science.gov (United States)

    Vermeulen, Isabel; Van Caneghem, Jo; Block, Chantal; Dewulf, Wim; Vandecasteele, Carlo

    2012-10-01

    Rotary kiln incinerators and cement kilns are two energy intensive processes, requiring high temperatures that can be obtained by the combustion of fossil fuel. In both processes, fossil fuel is often substituted by high or medium calorific waste to avoid resource depletion and to save costs. Two types of industrial calorific waste streams are considered: automotive shredder residue (ASR) and meat and bone meal (MBM). These waste streams are of current high interest: ASR must be diverted from landfill, while MBM can no longer be used for cattle feeding. The environmental impact of the incineration of these waste streams is assessed and compared for both a rotary kiln and a cement kiln. For this purpose, data from an extensive emission inventory is applied for assessing the environmental impact using two different modeling approaches: one focusing on the impact of the relevant flows to and from the process and its subsystems, the other describing the change of environmental impact in response to these physical flows. Both ways of assessing emphasize different aspects of the considered processes. Attention is paid to assumptions in the methodology that can influence the outcome and conclusions of the assessment. It is concluded that for the incineration of calorific wastes, rotary kilns are generally preferred. Nevertheless, cement kilns show opportunities in improving their environmental impact when substituting their currently used fuels by more clean calorific waste streams, if this improvement is not at the expense of the actual environmental impact.

  12. German Cement Industry's voluntary efforts on the issue of climate change : a success story

    Energy Technology Data Exchange (ETDEWEB)

    Hoenig, V.; Schneider, M. [German Cement Industry (Germany)

    2001-07-01

    In 1995, the cement industry in Germany stated that it would reduce energy consumption by 20 per cent between 1987 and 2005. In 2000, this commitment was adapted to international agreements such as the Kyoto Protocol. The voluntary agreement now includes a reduction of the specific energy-related carbon dioxide emissions from 1990 to 2008/12 by 28 per cent. Burning and grinding facilities have been optimized in recent years and the cement industry in Germany is planning to increase the use of fossil fuels by using waste products and by promoting the marketing of blended cements. The energy related carbon dioxide emissions were reduced by 3.6 million tonnes per year from 1987 to 1999 in the German cement industry as a result of these efforts. The use of waste products has also been increased from 4 to 23 per cent during this same time period and the clinker portion in cement has been decreased from 86 to 80.6 per cent. Granulated blast-furnace slag and unburned limestone has become the main constituent in cement. This paper also discussed the extent to which other instruments such as emissions trading, joint implementation and the clean development mechanism will have on the future of the cement industry. This paper was divided into several sections entitled: (1) voluntary agreement on climate change, (2) improvement in manufacturing processes, (3) optimization of existing kilns, (4) waste heat recovery, (5) reduction of electric power consumption, (6) remaining energy reduction potentials, (7) promotion of blended cement consumption, (8) market development, (9) use of secondary fuels, (10) greenhouse gas emissions, (11) energy related carbon dioxide emissions, (12) carbon dioxide emissions from the calcination of limestone, and (13) other greenhouse gas emissions. 3 tabs., 9 figs.

  13. PIXE characterization of by-products resulting from the zinc recycling of industrial cemented carbides

    Energy Technology Data Exchange (ETDEWEB)

    Freemantle, C.S. [School of Chemical & Metallurgical Engineering and DST-NRF Centre of Excellence in Strong Materials, University of the Witwatersrand, P/Bag 3, Wits 2050 (South Africa); Pilot Tools (Pty) (Ltd), P.O. Box 27420, Benrose 2011 (South Africa); Sacks, N. [School of Chemical & Metallurgical Engineering and DST-NRF Centre of Excellence in Strong Materials, University of the Witwatersrand, P/Bag 3, Wits 2050 (South Africa); Topic, M. [iThemba LABS, National Research Foundation, P.O. Box 722, Somerset West 7129 (South Africa); Pineda-Vargas, C.A. [iThemba LABS, National Research Foundation, P.O. Box 722, Somerset West 7129 (South Africa); Faculty of Health & Wellness Sciences, CPUT, Bellville (South Africa)

    2015-11-15

    By-product materials of the widely used zinc recycling process of cemented carbides have been studied. Scanning electron microscopy and micro-PIXE techniques have identified elemental concentrations, distributions and purity of by-product materials from an industrial zinc recycling plant. Cobalt surface enrichment, lamellar microstructures of varying composition, including alternating tungsten carbide (WC) grains and globular cobalt, and regions of excess zinc contamination were found in materials with incomplete zinc penetration. Liquid Co–Zn formation occurred above 72 wt.% Zn at the furnace temperature of 930 °C, and was extracted towards the surface of poorly zinc infiltrated material, primarily by the vacuum used for zinc distillation. Surface enrichment was not observed in material that was zinc infiltrated to the sample center, which was more friable and exhibited more homogeneous porosity and elemental concentrations. The result of incomplete zinc infiltration was an enriched surface zone of up to 60 wt.% Co, compared to an original sample composition of ∼10–15 wt.% Co. The impact on resulting powders could be higher or inhomogeneous cobalt content, as well as unacceptably high zinc concentrations. PIXE has proven it can be a powerful technique for solving industrial problems in the cemented carbide cutting tool industry, by identifying trace elements and their locations (such as Zn to 0.1 wt.% accuracy), as well as the distribution of major elements within WC–Co materials.

  14. Use of secondary fuels in rotary kilns of the cement industry; Einsatz von Sekundaerstoffen in Drehofenanlagen der Zementindustrie

    Energy Technology Data Exchange (ETDEWEB)

    Hoenig, V. [Forschungsinstitut der Zementindustrie, Duesseldorf (Germany)

    1998-09-01

    Most cement works in Germany use secondary materials for cement production or are planning to do so. Many of the materials in question, such as used tyres, have been recycled in an environmentally acceptable way for decades, and a large body of experience has accumulated on their use in the cement industry. In the cement industry secondary materials are understood to comprise secondary fuels as well as secondary raw materials. The latter have for some part replaced the natural raw materials used for burning cement clinker, the preliminary product of cement. By using used tyres, used oil and other waste materials as secondary fuels the cement industry has for decades contributed to an environmentally acceptable form of waste disposal. The use of secondary materials has also enabled the cement industry to improve its economic situation. In response to the enactment of the Materials Recycling Law the cement industry has during the past few years turned its attention to the utilisation of other waste materials. The criteria relevant to the cement industry`s choice of a waste material as secondary material lastly depends on the process-related side constraints attending the clinker burning process and the requirements on the burning process with regard to product quality and environmental acceptability. [Deutsch] Die meisten Zementwerke in Deutschland setzen bei der Zementherstellung Sekundaerstoffe ein oder planen ihren Einsatz. Fuer einige dieser Stoffe, wie z.B. Altreifen gilt, dass sie bereits seit Jahrzehnten umweltvertraeglich verwertet werden, so dass viele Erfahrungen ueber deren Einsatz in der Zementindustrie vorliegen. Unter Sekundaerstoffen werden in der Zementindustrie sowohl Sekundaerbrennstoffe wie auch Sekundaerrohstoffe verstanden. Letztere ersetzen teilweise die natuerlichen Rohstoffe, aus denen der Zementklinker, das Vorprodukt des Zements, gebrannt wird. Bezueglich der Sekundaerbrennstoffe traegt die Zementindustrie schon seit Jahrzehnten zu einer

  15. Modeling energy efficiency to improve air quality and health effects of China’s cement industry

    OpenAIRE

    2016-01-01

    Actions to reduce the combustion of fossil fuels often decrease GHG emissions as well as air pollutants and bring multiple benefits for improvement of energy efficiency, climate change, and air quality associated with human health benefits. The China’s cement industry is the second largest energy consumer and key emitter of CO2 and air pollutants, which accounts for 7% of China’s total energy consumption, 15% of CO2, and 14% of PM2.5, respectively. In this study, a state-of-the art modeling f...

  16. Evaluating co-benefits of energy efficiency and air pollution abatement in China’s cement industry

    NARCIS (Netherlands)

    Zhang, Shaohui; Worrell, Ernst; Crijns - Graus, Wina

    2015-01-01

    China’s cement industry is the world’s largest and is one of the largest energy consuming, and GHG and air pollutant emitting industries. Actions to improve energy efficiency by best available technology can often bring co-benefits for climate change and air quality through reducing emissions of GHG

  17. Energy efficiency at Parana state, BR, industrial sector: trends and perspectives; Eficiencia energetica no setor industrial do Parana: tendencias e perspectivas

    Energy Technology Data Exchange (ETDEWEB)

    Moraes, Gustavo Inacio de [Universidade de Sao Paulo (USP), Piracicaba, SP (Brazil). Escola Superior de Agricultura Luiz de Queiroz (ESALQ)]. E-mail: gimoraes@esalq.usp.br; Serra, Mauricio Aguiar [Universidade Federal do Parana (UFPR), Curitiba, PR (Brazil). Dept. de Economia]. E-mail: serra@ufpr.br

    2006-07-01

    From a social and economic scenario up to 2023, the energy intensity trajectory per capita and energy intensity per product are calculated at the Parana state, BR. An economic growing more intense could request less participation of the industrial sector related to service sector; however the necessity of action intensification viewing the energy efficiency of the sector yet will be important.

  18. Assessment of Energy Efficiency Improvement and CO2 Emission Reduction Potentials in India's Cement Industry

    Energy Technology Data Exchange (ETDEWEB)

    Morrow, III, William R. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Hasanbeigi, Ali [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Xu, Tengfang [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2012-12-03

    India’s cement industry is the second largest in the world behind China with annual cement production of 168 Mt in 2010 which accounted for slightly greater than six percent of the world’s annual cement production in the same year. To produce that amount of cement, the industry consumed roughly 700 PJ of fuel and 14.7 TWh of electricity. We identified and analyzed 22 energy efficiency technologies and measures applicable to the processes in the Indian cement industry. The Conservation Supply Curve (CSC) used in this study is an analytical tool that captures both the engineering and the economic perspectives of energy conservation. Using a bottom-up electricity CSC model and compared to an electricity price forecast the cumulative cost-effective plant-level electricity savings potential for the Indian cement industry for 2010- 2030 is estimated to be 83 TWh, and the cumulative plant-level technical electricity saving potential is 89 TWh during the same period. The grid-level CO2 emissions reduction associated with cost-effective electricity savings is 82 Mt CO2 and the electric grid-level CO2 emission reduction associated with technical electricity saving potential is 88 Mt CO2. Compared to a fuel price forecast, an estimated cumulative cost-effective fuel savings potential of 1,029 PJ with associated CO2 emission reduction of 97 Mt CO2 during 2010-2030 is possible. In addition, a sensitivity analysis with respect to the discount rate used is conducted to assess the effect of changes in this parameter on the results. The result of this study gives a comprehensive and easy to understand perspective to the Indian cement industry and policy makers about the energy efficiency potential and its associated cost over the next twenty years.

  19. Early Implementation of Large Scale Carbon Dioxide Removal Projects through the Cement Industry

    Science.gov (United States)

    Zeman, F. S.

    2014-12-01

    The development of large-scale carbon dioxide reduction projects requires high purity CO2and a reactive cation source. A project seeking to provide both of these requirements will likely face cost barriers with current carbon prices. The cement industry is a suitable early implementation site for such projects by virtue of the properties of its exhaust gases and those of waste concrete. Cement plants are the second largest source of industrial CO2 emissions, globally. It is also the second largest commodity after water, has no ready substitute and is literally the foundation of society. Finally, half of the CO2 emissions originate from process reactions rather than fossil fuel combustion resulting in higher flue gas CO2concentrations. These properties, with the co-benefits of oxygen combustion, create a favorable environment for spatially suitable projects. Oxygen combustion involves substituting produced oxygen for air in a combustion reaction. The absence of gaseous N2 necessitates the recirculation of exhaust gases to maintain kiln temperatures, which increase the CO2 concentrations from 28% to 80% or more. Gas exit temperatures are also elevated (>300oC) and can reach higher temperatures if the multi stage pre-heater towers, that recover heat, are re-designed in light of FGR. A ready source of cations can be found in waste concrete, a by-product of construction and demolition activities. These wastes can be processed to remove cations and then reacted with atmospheric CO2 to produce carbonate minerals. While not carbon negative, they represent a demonstration opportunity for binding atmospheric CO2while producing a saleable product (precipitated calcium carbonate). This paper will present experimental results on PCC production from waste concrete along with modeling results for oxygen combustion at cement facilities. The results will be presented with a view to mineral sequestration process design and implementation.

  20. Periclase spinel bricks in the cement industry. Periklas-Spinell-Steine in der Zementindustrie

    Energy Technology Data Exchange (ETDEWEB)

    Olbrich, M.; Dobrowsky, F.

    1989-10-01

    Intensified environmental requirements are leading some countries to abandon refractory products which contain chromium. The industry is being asked to develop corresponding products which are free from chrome ore so that substitution is possible without a break. In addition to spinel bricks which are produced by a reaction between Al{sub 2}O{sub 3} and MgO when the brick is fired there are also those containing spinel which has been prepared in advance. The present article makes a partial comparison of the two types with respect to their important physical test values. Details are also given of their thermomechanical and coating behaviours including a comparison with traditional magnesia chrome bricks. The comparison shows that the refractory industry is in a position to offer a complete, chrome-free, lining for rotary cement kilns which can even show improvements in quality. (orig.).

  1. Accelerated weathering of limestone for CO2 mitigation opportunities for the stone and cement industries

    Science.gov (United States)

    Langer, W.H.; Juan, C.A.S.; Rau, G.H.; Caldeira, K.

    2009-01-01

    Large amounts of limestone fines coproduced during the processing of crushed limestone may be useful in the sequestration of carbon dioxide (CO 2). Accelerated weathering of limestone (AWL) is proposed as a low-tech method to capture and sequester CO2 from fossil fuel-fired power plants and other point-sources such as cement manufacturing. AWL reactants are readily available, inexpensive, and environmentally benign. Waste CO 2 is hydrated with water to produce carbonic acid, which then reacts with and is neutralized by limestone fines, thus converting CO2 gas to dissolved calcium bicarbonate. AWL waste products can be disposed of in the ocean. Feasibility requires access to an inexpensive source of limestone and to seawater, thus limiting AWL facilities within about 10 km of the coastline. The majority of U.S. coastal power generating facilities are within economical transport distance of limestone resources. AWL presents opportunities for collaborative efforts among the crushed stone industry, electrical utilities, cement manufactures, and research scientists.

  2. Incidence of cancer and mortality among employees in the asbestos cement industry in Denmark

    DEFF Research Database (Denmark)

    Raffn, E; Lynge, E; Juel, K

    1989-01-01

    In a cohort study of the incidence of cancer and mortality among 7996 men and 584 women employed in the Danish asbestos cement industry between 1928 and 1984 over 99% were traced. Chrysotile asbestos was the only fibre type used until 1946, when amosite and (in 1952) crocidolite were also...... introduced. Chrysotile constituted 89%, amosite 10%, and crocidolite 1% of the asbestos used. During the first 25 years of manufacture the exposure levels were high, especially in areas where the asbestos was handled dry. Measurements from 1948 indicate that the fibre levels may have ranged from 100 to 1600...... for men for non-malignant pulmonary diseases (O/E 1.63; 95% CI 1.33-1.98). Among the group of asbestos cement workers with first employment 1928-40 an excess risk of laryngeal cancer was found (O/E 5.50;95% CI 1.77-12.82). A total of 12 cases of pleural and one of peritoneal mesotheliomas was observed...

  3. Assessment of Energy Efficiency Improvement and CO2 Emission Reduction Potentials in the Cement Industry in China

    Energy Technology Data Exchange (ETDEWEB)

    Hasanbeigi, Ali [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Morrow, William [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Masanet, Eric [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Sathaye, Jayant [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Xu, Tengfang [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2012-06-15

    China’s annual cement production (i.e., 1,868 Mt) in 2010 accounted for nearly half of the world’s annual cement production in the same year. We identified and analyzed 23 energy efficiency technologies and measures applicable to the processes in the cement industry. The Conservation Supply Curve (CSC) used in this study is an analytical tool that captures both the engineering and the economic perspectives of energy conservation. Using a bottom-up electricity CSC model, the cumulative cost-effective electricity savings potential for the Chinese cement industry for 2010-2030 is estimated to be 251 TWh, and the total technical electricity saving potential is 279 TWh. The CO2 emissions reduction associated with cost-effective electricity savings is 144 Mt CO2 and the CO2 emission reduction associated with technical electricity saving potential is 161 Mt CO2. The fuel CSC model for the cement industry suggests cumulative cost-effective fuel savings potential of 4,326 PJ which is equivalent to the total technical potential with associated CO2 emission reductions of 406 Mt CO2. In addition, a sensitivity analysis with respect to the discount rate used is conducted to assess the effect of changes in this parameter on the results. We also developed a scenario in which instead of only implementing the international technologies in 2010-2030, we implement both international and Chinese domestic technologies during the analysis period and calculate the saving and cost of conserved energy accordingly. The result of this study gives a comprehensive and easy to understand perspective to the Chinese cement industry and policy makers about the energy efficiency potential and its associated cost.

  4. Application of ESP for gas cleaning in cement industry--with reference to India.

    Science.gov (United States)

    Bapat, J D

    2001-02-16

    Electrostatic precipitators (ESP) are used for gas cleaning in almost every section of cement manufacture. Application of ESP is studied, keeping in view Indian conditions. The characterisation of dust emissions has been done for different units, such as rotary kiln and raw mill, alkali by-pass, clinker cooler, cement and coal mill, in terms of exit gas quantity, temperature, dew point, dust content and particle size. It is seen that all these characteristics have a wide range of variance. The ESP system must effectively deal with these variations. The fundamental analytical expression governing the performance of ESP, i.e. the Deutsch equation, and that for particle migration velocity, were analysed to predict the effect of major operating parameters, namely particle size, temperature and applied voltage. Whereas the migration velocity (and the efficiency) varies directly with the particle size, it is proportional to the square and square root of applied voltage and absolute temperature of the gas, respectively. The increase in efficiency due to temperature is not seen in dc based ESP, perhaps due to more pronounced negative effect on the applied voltage due to the increase in dust resistivity at higher temperatures. The effect of gas and dust characteristics on the collection efficiency of ESP, as seen in the industrial practice, is summarised. Some main process and design improvements effectively dealing with the problem of gas and dust characteristics have been discussed. These are gas conditioning, pulse energization, ESP-fabric filter (FF) combination, improved horizontal flow as well as open top ESP.Generally, gas conditioning entails higher operating and maintenance costs. Pulse energization allows the use of hot gas, besides reducing the dust emission and power consumption. The improved horizontal flow ESP has been successfully used in coal dust cleaning. The open top or vertical flow ESP has a limitation on collection efficiency as it provides for only

  5. Energy Efficient Microwave Hybrid Processing of Lime for Cement, Steel, and Glass Industries

    Energy Technology Data Exchange (ETDEWEB)

    Fall, Morgana L; Yakovlev, Vadim; Sahi, Catherine; Baranova, Inessa; Bowers, Johnney G; Esquenazi\t, Gibran L

    2012-02-10

    MAT in the US lime industry. This estimate showed that 7.3 TBTU/year could be saved, with reduction of 270 MMlbs of CO2 emissions, and $29 MM/year in economic savings. Taking into account estimates for MAT implementation in the US cement industry, an additional 39 TBTU/year, 3 Blbs of CO2 and $155 MM/year could be saved. One of the main remaining barriers to commercialization of MAT for the lime and cement industries is the sheer size of production. Through this project, it was realized that a production size MAT rotary calciner was not feasible, and a different approach was adapted. The concept of a microwave post heat section located in the upper portion of the cooler was devised and appears to be a more realistic approach for MAT implementation. Commercialization of this technology will require (1) continued pilot scale calcining demonstrations, (2) involvement of lime kiln companies, and (3) involvement of an industrial microwave equipment provider. An initial design concept for a MAT post-heat treatment section was conceived as a retrofit into the cooler sections of existing lime rotary calciners with a 1.4 year payback. Retrofitting will help spur implementation of this technology, as the capital investment will be minimal for enhancing the efficiency of current rotary lime kilns. Retrofits would likely be attractive to lime manufacturers, as the purchase of a new lime kiln is on the order of a $30 million dollar investment, where as a MAT retrofit is estimated on the order of $1 million. The path for commercialization lies in partnering with existing lime kiln companies, who will be able to implement the microwave post heat sections in existing and new build kilns. A microwave equipment provider has been identified, who would make up part of the continued development and commercialization team.

  6. Reduction of soil pollution by usingwaste of the limestone in the cement industry

    Science.gov (United States)

    Muñoz, M. Cecilia Soto; Robles Castillo, Marcelo; Blanco Fernandez, David; Diaz Gonzalez, Marcos; Naranjo Lamilla, Pedro; Moore Undurraga, Fernando; Pardo Fabregat, Francisco; Vidal, Manuel Miguel Jordan; Bech, Jaume; Roca, Nuria

    2016-04-01

    In the cement manufacturing process (wet) a residue is generated in the flotation process. This builds up causing contamination of soil, groundwater and agricultural land unusable type. In this study to reduce soil and water pollution 10% of the dose of cement was replaced by waste of origin limestone. Concretes were produced with 3 doses of cement and mechanical strengths of each type of concrete to 7, 28 and 90 days were determined. the results indicate that the characteristics of calcareous residue can replace up to 10% of the dose of cement without significant decreases in strength occurs. It is noted that use of the residue reduces the initial resistance, so that the dose of cement should not be less than 200 kg of cement per m3. The results allow recommends the use of limestone waste since it has been observed decrease in soil and water contamination without prejudice construction material Keywords: Soil contamination; Limestone residue; Adding concrete

  7. Commerical-Scale CO2 Capture and Sequestration for the Cement Industry

    Energy Technology Data Exchange (ETDEWEB)

    Adolfo Garza

    2010-07-28

    On June 8, 2009, DOE issued Funding Opportunity Announcement (FOA) Number DE-FOA-000015 seeking proposals to capture and sequester carbon dioxide from industrial sources. This FOA called for what was essentially a two-tier selection process. A number of projects would receive awards to conduct front-end engineering and design (FEED) studies as Phase I. Those project sponsors selected would be required to apply for Phase II, which would be the full design, construction, and operation of their proposed technology. Over forty proposals were received, and ten were awarded Phase I Cooperative Agreements. One of those proposers was CEMEX. CEMEX proposed to capture and sequester carbon dioxide (CO2) from one of their existing cement plants and either sequester the CO2 in a geologic formation or use it for enhanced oil recovery. The project consisted of evaluating their plants to identify the plant best suited for the demonstration, identify the best available capture technology, and prepare a design basis. The project also included evaluation of the storage or sequestration options in the vicinity of the selected plant.

  8. Biomass use in the Dutch cement industry ENCI, Maastricht, The Netherlands

    NARCIS (Netherlands)

    Junginger, H.M.

    2009-01-01

    Based in the Netherlands, ENCI is a division of HeidelbergCement active in the Benelux countries. It possesses three main production facilities in the Netherlands, of which the biggest is the integrated production plant in Maastricht. ENCI has been generating cement from Maastricht since 1926, and d

  9. Impact of Working Capital Management on Firm’s Profitability: A Case Study of Cement Industry of Pakistan

    Directory of Open Access Journals (Sweden)

    Farrukh Shahzad

    2015-02-01

    Full Text Available The fundamental purpose behind this study is to exactly test the effect of working capital management on profitability of cement industry of Pakistan. To explore this relationship between these two, the creator gathered auxiliary information from 12 listed firms in Karachi stock exchange (KSC for the time period of 2007-2013. For this reason, in this study we utilize variable of return on assets ratio to gauge the benefit of organization and variables of CR, QR, NCA/TA, WCT and ITR as living up to expectations working capital management criteria. The consequences of the research demonstrate that there is a huge effect of the working capital management on profitability of cement industry of Pakistan. Accordingly, manager may improve the Profitability of their organizations by minimizing the inventory turnover ratio, and by diminishing working capital turnover ratio but there is no impact of expanding or diminishing the current proportion on profitability. Along these lines, the results show that through fitting working capital management the organization can expand its benefit. This study shall be helping hand for the cement industry of Pakistan in the management of their working capital in such an effective way thus, to the point that they can increase their profitability.

  10. Incidence of cancer and mortality among employees in the asbestos cement industry in Denmark.

    Science.gov (United States)

    Raffn, E; Lynge, E; Juel, K; Korsgaard, B

    1989-01-01

    In a cohort study of the incidence of cancer and mortality among 7996 men and 584 women employed in the Danish asbestos cement industry between 1928 and 1984 over 99% were traced. Chrysotile asbestos was the only fibre type used until 1946, when amosite and (in 1952) crocidolite were also introduced. Chrysotile constituted 89%, amosite 10%, and crocidolite 1% of the asbestos used. During the first 25 years of manufacture the exposure levels were high, especially in areas where the asbestos was handled dry. Measurements from 1948 indicate that the fibre levels may have ranged from 100 to 1600 times over the present Danish threshold limit value of 0.5 fibre/ml. In 1973 more than 41% of personal samples were higher than 2 f/ml. About 76% of the workforce left the factory within five years of starting employment. A total of 1346 deaths and 612 cases of cancer were observed in the cohort between 1943 and 1984. Among employed men the overall mortality (O/E 1.18; 95% CI 1.12-1.25), cancer mortality (O/E 1.32; 95% CI 1.19-1.46), and overall incidence of cancer (O/E 1.22; 95% CI 1.12-1.32) were significantly increased compared with all Danish men. This was not so among employed women. For men, significant excess risks were found for cancer of the lung (O/E 1.80; 95% CI 1.54-2.10), pleura (O/E 5.46; 95% CI 2.62-10.05), mediastinum (O/E 5.00; 95% CI 1.01-14.61), stomach (O/E 1.43; 95% CI 1.03-1.93), and other male genital organs (O/E 3.03; 95% CI 1.11-6.60). The mortality was significantly increased for men for non-malignant pulmonary diseases (O/E 1.63; 95% CI 1.33-1.98). Among the group of asbestos cement workers with first employment 1928-40 an excess risk of laryngeal cancer was found (O/E 5.50;95% CI 1.77-12.82). A total of 12 cases of pleural and one of peritoneal mesotheliomas was observed when the original notification forms were reviewed for all patients with cancer in the cohort. PMID:2923830

  11. Methodological and Practical Considerations for DevelopingMultiproject Baselines for Electric Power and Cement Industry Projects inCentral America

    Energy Technology Data Exchange (ETDEWEB)

    Murtishaw, Scott; Sathaye, Jayant; Galitsky, Christina; Dorion,Kristel

    2004-09-02

    The Lawrence Berkeley National Laboratory (Berkeley Lab) andthe Center for Sustainable Development in the Americas (CSDA) conductedtechnical studies and organized two training workshops to developcapacity in Central America for the evaluation of climate changeprojects. This paper describes the results of two baseline case studiesconducted for these workshops, one for the power sector and one for thecement industry, that were devised to illustrate certain approaches tobaseline setting. Multiproject baseline emission rates (BERs) for themain Guatemalan electricity grid were calculated from 2001 data. Inrecent years, the Guatemalan power sector has experienced rapid growth;thus, a sufficient number of new plants have been built to estimateviable BERs. We found that BERs for baseload plants offsetting additionalbaseload capacity ranged from 0.702 kgCO2/kWh (using a weighted averagestringency) to 0.507 kgCO2/kWh (using a 10th percentile stringency),while the baseline for plants offsetting load-followingcapacity is lowerat 0.567 kgCO2/kWh. For power displaced from existing load-followingplants, the rate is higher, 0.735 kgCO2/kWh, as a result of the age ofsome plants used for meeting peak loads and the infrequency of their use.The approved consolidated methodology for the Clean Development Mechanismyields a single rate of 0.753 kgCO2/kWh. Due to the relatively smallnumber of cement plants in the region and the regional nature of thecement market, all of Central America was chosen as the geographicboundary for setting cement industry BERs. Unfortunately, actualoperations and output data were unobtainable for most of the plants inthe region, and many data were estimated. Cement industry BERs rangedfrom 205 kgCO2 to 225 kgCO2 per metric ton of cement.

  12. 水泥窑处理工业废物的工厂实验研究%Plant Test of Industrial Waste Disposal in a Cement Kiln

    Institute of Scientific and Technical Information of China (English)

    刘阳生; 韩杰; 白庆中

    2003-01-01

    Destruction of industrial waste in cement rotary kilns (CRKs) is an alternative technology for thetreatment of certain types of industrial waste (IW). In this paper, three typical types of industrial wastes wereco-incinerated in the CRK at Beijing Cement Plant to determine the effects of waste disposal (especially solid wastedisposal) on the quality of clinker and the concentration of pollutants in air emission. Experimental results showthat (1) waste disposal does not affect the quality of clinker and fly ash, and fly ash after the IW disposal can still beused in the cement production, (2) heavy metals from IW are immobilized and stabilized in the clinker and cement,and (3) concentration of pollutants in air emission is far below than the permitted values in the China NationalStandard-Air Pollutants Emission Standard (GB 16297-1996).

  13. Recycling of the product of thermal inertization of cement-asbestos for various industrial applications.

    Science.gov (United States)

    Gualtieri, Alessandro F; Giacobbe, Carlotta; Sardisco, Lorenza; Saraceno, Michele; Gualtieri, Magdalena Lassinantti; Lusvardi, Gigliola; Cavenati, Cinzia; Zanatto, Ivano

    2011-01-01

    Recycling of secondary raw materials is a priority of waste handling in the countries of the European community. A potentially important secondary raw material is the product of the thermal transformation of cement-asbestos, produced by prolonged annealing at 1200-1300 °C. The product is chemically comparable to a Mg-rich clinker. Previous work has assured the reliability of the transformation process. The current challenge is to find potential applications as secondary raw material. Recycling of thermally treated asbestos-containing material (named KRY·AS) in traditional ceramics has already been studied with successful results. The results presented here are the outcome of a long termed project started in 2005 and devoted to the recycling of this secondary raw materials in various industrial applications. KRY·AS can be added in medium-high percentages (10-40 wt%) to commercial mixtures for the production of clay bricks, rock-wool glasses for insulation as well as Ca-based frits and glass-ceramics for the production of ceramic tiles. The secondary raw material was also used for the synthesis of two ceramic pigments; a green uvarovite-based pigment [Ca(3)Cr(2)(SiO(4))(3)] and a pink malayaite-based pigment [Ca(Sn,Cr)SiO(5)]. The latter is especially interesting as a substitute for cadmium-based pigments. This work also shows that KRY·AS can replace standard fillers in polypropylene plastics without altering the properties of the final product. For each application, a description and relevant results are presented and discussed.

  14. Quantifying the Co-benefits of Energy-Efficiency Programs: A Case Study of the Cement Industry in Shandong Province, China

    Energy Technology Data Exchange (ETDEWEB)

    Hasanbeigi, Ali [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Lobscheid, Agnes [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Dai, Yue [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Lu, Hongyou [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Price, Lynn [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2012-11-01

    China’s cement industry accounted for more than half of the world’s total cement production in 2010. The cement industry is one of the most energy-intensive and highest carbon dioxide (CO2)-emitting industries and one of the key industrial contributors to air pollution in China. For example, it is the largest source of particulate matter (PM) emissions in China, accounting for 40 percent of industrial PM emissions and 27 percent of total national PM emissions. Although specific regulations and policies are needed to reduce the pollutant emissions from the cement industry, air pollution can also be reduced as a co-benefit of energy efficiency and climate-change mitigation policies and programs. Quantifying and accounting for these co-benefits when evaluating energy efficiency and climate-change mitigation programs reveals benefits beyond the programs’ energy and global warming impacts and adds to their cost effectiveness. In this study, we quantify the co-benefits of PM10 and sulfur dioxide (SO2) emissions reductions that result from energy-saving measures in China’s cement industry.

  15. Effects of Riyadh cement industry pollutions on some physiological and morphological factors of Datura innoxia Mill. plant.

    Science.gov (United States)

    Salama, Hediat M H; Al-Rumaih, M M; Al-Dosary, M A

    2011-07-01

    Cement factory emissions into air cause serious air pollution and affect the plant and animal life in the environment. Herein, we report the effects of cement industry emissions (O3, SO2 and NO2) in air, as pollutants, at Riyadh City on Datura innoxia Mill. plant. Morphological characters including plant height, leaves area and number, fresh and dry weight of shoot and root systems of D. innoxia showed a significant reduction from their normal control plants as a response to exposure to pollutant emissions. Chlorophyll and carotenoid contents recorded reductions in values compared to control plant, and the lowest values of chlorophyll A, B, total chlorophyll, carotenoids and total pigments were 0.431, 0.169, 0.60, 0.343 and 0.943 mg/g respectively at a distance of 1-5 m from the cement factory in fruiting stage. These changes in values may be attributed to a probable deceleration of the biosynthetic process rather than degradation of pigments. Further D. innoxia showed a significant (P plant. The root system recorded the lowest values of reducing sugars (0.350 mg/g f. wt.), non-reducing sugars (0.116 mg/g f. wt.), total sugars (0.466 mg/g f. wt.), protein content (0.931 mg/g f. wt.) and total lipids content (0.669 mg/g f. wt.) in fruiting stage at a distance of 1-5 m from the cement factory. The peroxidase activity of shoot and root systems of the studied plant was also significantly higher than those of control plant. Thus a highest value of (29.616 units/g f. wt.) peroxidase activity was recorded in vegetative stage of shoot system at a distance 1-5 m from the cement factory. Results of the study indicated that cement industry emission strongly influence the physiology and morphology of date palm D. innoxia which contribute date fruits, a staple food in the Arab world.

  16. Tendencias en investigación sobre seguridad y salud laboral: Propuesta metodológica aplicada al sector de la construcción Trends in research about occupational safety and health: Methodology applied to the construction industry

    Directory of Open Access Journals (Sweden)

    Gloria Isabel Carvajal Peláez

    2009-07-01

    Full Text Available En este artículo se realiza un análisis de las tendencias en investigación sobre seguridad y salud ocupacional aplicadas al sector de la construcción. Se investigaron fuentes publicadas en inglés (1930 -2007 y se encontraron más de 250 artículos. Para clasificar la información, se propone el "ciclo riesgo accidente" formado por cinco pasos que reflejan la realidad de la seguridad laboral en la construcción. Para cada paso, se seleccionaron las publicaciones más representativas y se elaboraron árboles de evolución lógica teniendo en cuenta el contenido, grado de importancia, orden cronológico, aplicación sobre cada tema, etc. Con estos árboles, se pasa de lo general a lo particular en forma cronológica, para demostrar las tendencias actuales en investigación en seguridad y salud en la construcción y podemos concluir que la investigación en este aspecto sigue siendo escasa, tratándose de un campo lleno de oportunidades y con un futuro prometedor.This article analyzes trends in research in occupational safety and health applied to the construction industry. The sources of information published in English (1930-2007 and found more than 250 articles. In order to classify these documents, is proposed the "risk-accident cycle" composes by five steps that reflect the reality of occupational safety and health in the construction industry. For each one of them, the papers more representative were selected and later elaborated a tree of chronological evolution considering aspects such as the content, degree of importance, chronological order, application on each subject, etc. With the elaboration of these trees, show the passage of the general to the particular in chronological form, for demonstrating the actual trends in research in safety and health in the construction. As a final remark, nowadays, research in safety and health in the construction is still very limited, being a field with many opportunities and a promising future.

  17. Use of the “red gypsum” industrial waste as substitute of natural gypsum for commercial cements manufacturing

    Directory of Open Access Journals (Sweden)

    Gázquez, M. J.

    2012-06-01

    Full Text Available The main objective of this research has been the valorisation of a waste from the TiO2 production process (sulphate method, called red gypsum, in the production of cements. This waste is mainly formed by di-hydrate calcium sulphate and iron hydroxides. To cover this objective it has been necessary to perform the physico-chemical characterisation of the red gypsum as well as the main components in the production of cements and of the new cements generated. Moreover, for the red gypsum, has been analyzed its radioactive content because it is generated in a NORM (Naturally Occurring Radioactive Materials industry. Finally, the most important properties of the obtained cements with different proportions of red gypsum in their composition have been studied by comparing them with the standard ones obtained in a Portland cement. Lastly, we have demonstrated that the new cements fulfil all the quality tests imposed by the European legislation.

    El objetivo de esta investigación ha sido analizar la valorización de un residuo generado en el proceso de producción de dióxido de titanio (vía sulfato, denominado yeso rojo, en la producción de cementos. Dicho residuo está compuesto fundamentalmente por sulfato de calcio di-hidratado e hidróxidos de hierro. Para ello, ha sido necesaria la caracterización físico-química del yeso rojo, así como la de los otros componentes fundamentales en la fabricación de cementos y de los cementos generados con el mencionado residuo. Además, en el caso del yeso rojo, se ha analizado su contenido radiactivo al generarse éste en una industria NORM (Natural Occurring Radioactive Materials. Posteriormente, se han estudiado las propiedades más importantes de los cementos producidos con diferentes porcentajes de yeso rojo añadido, comparando estas mezclas con las propiedades de un cemento Portland comercial, comprobándose que se cumplen todas las normas Europeas de calidad exigibles.

  18. CONTRIBUTION TO THE STATISTICAL INTERPRETATION OF RAW MATERIALS FOR THE CEMENT INDUSTRY OF SPLIT

    Directory of Open Access Journals (Sweden)

    Miroslav Matijaca

    1990-12-01

    Full Text Available Up to the last two decades cement was produced from mari called »tupina« (with about 76% CaCOj which is an ideal mixture for cement production. Due to the quantity decrease of this raw material, cement production went on using the mixture of other members of the flysch series: limestones, marls, clay, loess, sandstones a.o. By the analysis of natural materials the CaCO^ content has mostly been proved. Therefore, knowing the correlation of oxides in mineral raw material is of special significance. The article discusses investigation results of the correlation between CaCO-i and other oxides of the raw material (the paper is published in Croatian.

  19. Explorations on Energy Management System Standardization in Cement Industry%水泥行业能源管理体系标准进展及实施探索

    Institute of Scientific and Technical Information of China (English)

    李燕; 王赓; 任香贵

    2014-01-01

    The energy-saving management of China’s cement industry has gradually improved in recent years;however, cement industry still faces big pressure of facilitating energy conservation and emission reduction. Based on the current development of cement industry, the paper summarizes and analyzes the application and promotion of energy management system (EnMS) standardization in cement industry, then gives a brief introduction to the implementation of related standards and at last explores the positive function of energy management system in enhancing enterprises’ energy management and improving energy performance.

  20. Application of thermal energy storage in the cement industry. Final report, September 1977--March 1978

    Energy Technology Data Exchange (ETDEWEB)

    Jaegr, F.A.; Beshore, D.G.; Miller, F.M.; Gartner, E.M.

    1978-10-01

    In the manufacture of cement, literally trillions of Btu's are rejected to the environment each year. The purpose of this feasibility study program was to determine whether thermal energy storage could be used to conserve or allow alternative uses of this rejected energy. This study identifies and quantifies the sources of rejected energy in the cement manufacturing process, establishes use of this energy, investigates various storage system concepts, and selects energy conservation systems for further study. Thermal performance and economic analyses are performed on candidate storage systems for four typical cement plants representing various methods of manufacturing cement. Through the use of thermal energy storage in conjunction with waste heat electric power generation units, an estimated 2.4 x 10/sup 13/ Btu/year, or an equivalent of 4.0 x 10/sup 6/ barrels of oil per year, can be conserved. Attractive rates of return on investment of the proposed systems are an incentive for further development.

  1. India's cement industry: Productivity, energy efficiency and carbon emissions

    Energy Technology Data Exchange (ETDEWEB)

    Schumacher, Katja; Sathaye, Jayant

    1999-07-01

    Historical estimates of productivity growth in India's cement sector vary from indicating an improvement to a decline in the sector's productivity. The variance may be traced to the time period of study, source of data for analysis, and type of indices and econometric specifications used for reporting productivity growth. Analysis shows that in the twenty year period, 1973 to 1993, productivity in the aluminum sector increased by 0.8% per annum. An econometric analysis reveals that technical progress in India's cement sector has been biased towards the use of energy and capital, while it has been material and labor saving. The increase in productivity was mainly driven by a period of progress between 1983 and 1991 following partial decontrol of the cement sector in 1982. The authors examine the current changes in structure and energy efficiency in the sector. Their analysis shows that the Indian cement sector is moving towards world-best technology, which will result in fewer carbon emissions and more efficient energy use. However, substantial further energy savings and carbon reduction potentials still exist.

  2. Efficiency modeling of solidification/stabilization of multi-metal contaminated industrial soil using cement and additives

    Energy Technology Data Exchange (ETDEWEB)

    Voglar, Grega E. [RDA - Regional Development Agency Celje, Kidriceva ulica 25, 3000 Celje (Slovenia); Lestan, Domen, E-mail: domen.lestan@bf.uni-lj.si [Agronomy Department, Centre for Soil and Environmental Science, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, 1000 Ljubljana (Slovenia)

    2011-08-30

    Highlights: {yields} We assess the feasibility of using soil S/S for industrial land reclamation. {yields} Retarders, accelerators, plasticizers were used in S/S cementitious formulation. {yields} We proposed novel S/S efficiency model for multi-metal contaminated soils. - Abstract: In a laboratory study, formulations of 15% (w/w) of ordinary Portland cement (OPC), calcium aluminate cement (CAC) and pozzolanic cement (PC) and additives: plasticizers cementol delta ekstra (PCDE) and cementol antikorodin (PCA), polypropylene fibers (PPF), polyoxyethylene-sorbitan monooleate (Tween 80) and aqueous acrylic polymer dispersion (Akrimal) were used for solidification/stabilization (S/S) of soils from an industrial brownfield contaminated with up to 157, 32,175, 44,074, 7614, 253 and 7085 mg kg{sup -1} of Cd, Pb, Zn, Cu, Ni and As, respectively. Soils formed solid monoliths with all cementitious formulations tested, with a maximum mechanical strength of 12 N mm{sup -2} achieved after S/S with CAC + PCA. To assess the S/S efficiency of the used formulations for multi-element contaminated soils, we propose an empirical model in which data on equilibrium leaching of toxic elements into deionized water and TCLP (toxicity characteristic leaching procedure) solution and the mass transfer of elements from soil monoliths were weighed against the relative potential hazard of the particular toxic element. Based on the model calculation, the most efficient S/S formulation was CAC + Akrimal, which reduced soil leachability of Cd, Pb, Zn, Cu, Ni and As into deionized water below the limit of quantification and into TCLP solution by up to 55, 185, 8750, 214, 4.7 and 1.2-times, respectively; and the mass transfer of elements from soil monoliths by up to 740, 746, 104,000, 4.7, 343 and 181-times, respectively.

  3. THE LIMITATION AND DEVELOPMENT OF CEMENT INDUSTRY IN HUANGSHI%黄石水泥工业的限制与发展

    Institute of Scientific and Technical Information of China (English)

    范方禄

    2001-01-01

    国家明令控制水泥总量,关闭小水泥厂,调整产业结构,黄石水泥工业产品过剩,且良莠不齐。本文就现状情况进行分析讨论,从小水泥厂淘汰看黄石水泥工业的出路。%It is ordered by our country that we should control the totaloutput of cement, close down small cement plants and adjust the industrial structure. In Huangshi,the product of the cement industry is overproduced and the industrial development is inhomogeneous. This essay discusses the current situation, Looking into its future when the small plants are eliminated.

  4. Design, quality, and quality assurance of solid recovered fuels for the substitution of fossil feedstock in the cement industry.

    Science.gov (United States)

    Sarc, R; Lorber, K E; Pomberger, R; Rogetzer, M; Sipple, E M

    2014-07-01

    This paper describes the requirements for the production, quality, and quality assurance of solid recovered fuels (SRF) that are increasingly used in the cement industry. Different aspects have to be considered before using SRF as an alternative fuel. Here, a study on the quality of SRF used in the cement industry is presented. This overview is completed by an investigation of type and properties of input materials used at waste splitting and SRF production plants in Austria. As a simplified classification, SRF can be divided into two classes: a fine, high-calorific SRF for the main burner, or coarser SRF material with low calorific value for secondary firing systems, such as precombustion chambers or similar systems. In the present study, SRFs coming from various sources that fall under these two different waste fuel classes are discussed. Both SRFs are actually fired in the grey clinker kiln of the Holcim (Slovensko) plant in Rohožnik (Slovakia). The fine premium-quality material is used in the main burner and the coarse regular-quality material is fed to a FLS Hotdisc combustion device. In general, the alternative fuels are used instead of their substituted fossil fuels. For this, chemical compositions and other properties of SRF were compared to hard coal as one of the most common conventional fuels in Europe. This approach allows to compare the heavy metal input from traditional and alternative fuels and to comment on the legal requirements on SRF that, at the moment, are under development in Europe.

  5. Ranking of Companies based on TOPSIS-DEA Approach Methods (Case Study of Cement Industry in Tehran Stock Exchange

    Directory of Open Access Journals (Sweden)

    Ali Mansory

    2014-08-01

    Full Text Available Ranking options has always been the main issue for managers. There are a lot of qualitative and quantitative approaches for ranking. However most of the approaches for separating and ranking corporations in stock market are less reliable and the results obtained will be invalid. While the evaluation obtained merely through qualitative or quantitative approaches alone, the advantages of integration will be ignored. Thus logically the efficiency of result will be questionable. Thus in this paper the advantages of qualitative and quantitative approaches are integrated which in turn bring about more precision in values of input and output indices. Hence in this paper the approaches, TOPSIS & DEA, have been introduced to rate active companies in cement industry accepted in Tehran stock market. The approach adopted in this paper is applicable and carried out during 2006-2011 and the population of the research includes accepted companies in stock market in cement industry (28 companies and at the end a precise ranking of the companies is presented by integrattive techniques.

  6. Tendencias actuales de los plásticos en la industria automovilística // Current trends of plastic in the car industry

    Directory of Open Access Journals (Sweden)

    G. Palmer Martín

    1998-01-01

    Full Text Available En el presente articulo se realiza un análisis de la inserción actual de los plásticos en la industria automovilística, posición queocupan en este mercado, ventajas generales que presentan frente a otros materiales de primera línea, principales materiasplásticas empleadas y aplicaciones fundamentales, entre otros aspectos de gran interés técnico y estadístico._______________________________________________________________________AbstractIn the present article is accomplished an analysis of the current insert of plastic in car industry, occupied position in thismarket, general advantages compared with other material of first line, principal employed plastic matters and fundamentalapplications, between other aspects of great technical and statistic interest.

  7. Influence of Environmentally Friendly and High-Efficiency Composite Additives on Pulverized Coal Combustion in Cement Industry

    Directory of Open Access Journals (Sweden)

    Zhiyong Wang

    2016-01-01

    Full Text Available 4 kinds of chemical reagents and 3 kinds of industrial wastes were selected as burning additives for 2 kinds of coals in cement industry. The work focused on the replacement of partial chemical reagents by industrial wastes, which not only reduced the cost and took full advantage of industrial wastes, but also guaranteed the high combustion efficiency and removed the NOX and SO2 simultaneously. The experiments were carried out in DTF. The combustion residues were analyzed by SEM and XRD. The results showed that the burnout rate was increased after adding the additives; meanwhile, the NOX and SO2 release concentration were reduced, but the degree of action varied for different additives and coals. The substitute of chemical reagents by industrial wastes was very effective; overall, the cold-rolled iron oxide worked better than others; the particles surface was tougher and the peaks of crystalline phase were lower than raw coal, which indicated that the additives played good roles in combustion process.

  8. Recent growth trends and challenges in the Norwegian aquaculture industry Tendencias recientes de crecimiento y desafíos de la industria acuícola en Noruega

    Directory of Open Access Journals (Sweden)

    Asbjørn Bergheim

    2012-09-01

    Full Text Available Over the last 20 years, the Norwegian production of salmon and rainbow trout has increased by about 10% per year and will exceed 1 million MT in 2010. All on-growing after stocking in sea takes place in open cages in the fjords and along the coast, and the average cage volume has increased by about 300 times since the 1980's. Out of a total number of 4,000 cages more than 1,200 cages hold 20,000-60,000 m³. In 2005, the term 'maximum allowable biomass (MAB' was introduced and limits the highest annual production to 65 tons per 1,000 m³ licensed volume. Generally, the increasing volume and deeper cages have made the control of the fish stock more challenging. Sea lice attacks, especially in South Norway, have represented a major problem over the last three years. Reduced growth, increased mortality and lice treatment leads to significant losses and extra costs for the industry. Some recent reports indicate that increased use of wrasses in the cages improved the situation in the summer 2010 compared to the previous year. Extensive vaccinating and strict regulations regarding handling, etc. usually result in effective protection against diseases, but still there may occur regional outbreaks of serious diseases, such as pancreas disease (PD and infectious salmon anaemia (ISA. Attacks of sea lice and escape of salmon and trout from fish farms are considered to be among the main reasons for the strongly reduced wild stocks of sea trout and a reduced return of salmon spawners in the fjords and along the coast of southwest Norway.Durante los últimos 20 anos, la producción de salmón y trucha arcoiris en Noruega se ha incrementado en un 10% al ano y sobrepasará 1 millón de toneladas para el 2010. Todo el proceso de "engorda" ocurre en balsas-jaulas emplazadas en los fiordos y zonas costeras. El volumen promedio de una balsa-jaula se ha incrementado en un 300% desde sus inicios en 1980. En un universo de 4,000 balsas-jaulas se tiene que más de 1

  9. POZZOLAN AND CEMENTS WITH POZZOLAN

    OpenAIRE

    Hasan KAPLAN; Hanifi BİNİCİ

    1995-01-01

    Cement, one of the basic material of construction engineering, has an important place in view of strength and cost of structures. Cement consumption is increasing parallel to development of building construction sector. For cement producers, minimal cost is desired by using new and economical material sources. On the other hand, the controllers and contractors need cheaper, safer and higher strength materials. From this respect cement industry tends to use cement with pozzolan. In Türkiye, ce...

  10. Synthesis and mechanical properties of a calcium sulphoaluminate cement made of industrial wastes

    Directory of Open Access Journals (Sweden)

    Gallardo, M.

    2014-09-01

    Full Text Available Environmentally-friendly calcium sulphoaluminate clinkers were obtained from a mixture of aluminium dross, fluorgypsum, fly ash and CaCO₃ at temperatures within the range of 1100 to 1400 °C. After the heat treatments Ca₄Al₆O₁₂SO₄ was the main phase. Three different cements were prepared using the clinkers synthesized at 1250, 1350 and 1400 °C; the clinker powders were mixed with 20 wt% of hemihydrate. Cement pastes were prepared using a water/cement ratio (w/c, 0.4 followed by curing at 20 or 40 °C for periods of time ranging from 1 to 28 days. Most of the samples showed high compression strengths 40–47 MPa after 28 days, which were comparable to the strength of Portland cement. Ettringite was the main hydration product and its morphology consisted of acicular and hexagonal plates, which is typical of this phase.Se fabricaron clinkers de bajo impacto ambiental a base de sulfoaluminato de calcio calcinando mezclas de escoria de aluminio, fluoryeso, ceniza volante y CaCO₃ a diferentes temperaturas dentro de un rango de 1100 a 1400 °C. Se observó la formación de Ca₄Al₆O₁₂SO₄ como fase principal. Para obtener los cementos, los clinkers obtenidos a 1250, 1350 y 1400 °C se mezclaron con 20% en peso de hemihidrato. Se prepararon pastas usando una relación agua/cemento, de 0.4 y se curaron a 20 y 40 °C por diferentes periodos de tiempo desde 1 hasta 28 días. Los valores de resistencia a la compresión a los 28 días de curado de la mayoría de las muestras estuvieron entre 40–47 MPa, equiparables a los de referencia de pastas de cemento Portland. La etringita fue el principal producto de hidratación y su morfología consistió de placas hexagonales y aciculares, típicas de esta fase.

  11. Long-term model-based projections of energy use and CO2emissions from the global steel and cement industries

    NARCIS (Netherlands)

    Van Ruijven, Bas J.; Van Vuuren, Detlef P.; Boskaljon, Willem; Neelis, Maarten L.; Saygin, Deger; Patel, Martin K.

    2016-01-01

    This paper presents a global simulation-model for the steel and cement industries. The model covers the full modelling chain from economic activity, to materials consumption, trade, technology choice, production capacity, energy use and CO2emissions. Without climate policy, the future projections ba

  12. Design, Explanation, and Evaluation of Training Model Structures Based on Learning Organization--In the Cement Industry with a Nominal Production Capacity of Ten Thousand Tons

    Science.gov (United States)

    Rahimian, Hamid; Kazemi, Mojtaba; Abbspour, Abbas

    2017-01-01

    This research aims to determine the effectiveness of training based on learning organization in the staff of cement industry with production capacity over ten thousand tons. The purpose of this study is to propose a training model based on learning organization. For this purpose, the factors of organizational learning were introduced by…

  13. Implementation of industrial waste ferrochrome slag in conventional and low cement castables: Effect of calcined alumina

    Directory of Open Access Journals (Sweden)

    Pattem Hemanth Kumar

    2014-12-01

    Full Text Available A new class of conventional and low-cement ferrochrome slag-based castables were prepared from 40 wt.% ferrochrome slag and 45 wt.% calcined bauxite. Rest fraction varied between high alumina cement (HAC acting as hydraulic binder and calcined alumina as pore filling additive. Standard ASTM size briquettes were prepared for crushing and bending strengths evaluation, and the samples were then subjected to firing at 800, 1100 and 1300 °C for a soaking period of 3 h. The microstructure and refractory properties of the prepared castables have been investigated using X-ray diffraction (XRD, scanning electron microscopy (SEM, cold crushing strength, modulus of rupture and permanent linear changes (PLCs test. Castables show good volume stability (linear change <0.7% at 1300 °C. The outcomes of these investigations were efficacious and in accordance with previously reported data of similar compositions. High thermo-mechanical and physico-chemical properties were attained pointing out an outstanding potential to increase the refractory lining working life of non-recovery coke oven and reheating furnaces.

  14. System of lower cogeneration in the cement industry; Sistema de cogeneracion inferior en la industria del cemento

    Energy Technology Data Exchange (ETDEWEB)

    Romero Paredes, H.; Vazquez, A; Ambriz, J. J.; Fosado, A.; Cedillo, D.; Sanchez, R. [Universidad Autonoma Metropolitana-Iztapalapa (Mexico)

    1999-07-01

    In this paper present work, the design of a cogeneration system was made, taking advantage of the waste thermal flows in a cement manufacturing industry. The costs by concept of energy sources in the cement industry represent between 30 and 60% of the production costs, reason why any diminution in its consumption, will be reflected considerably in the productivity of the company. In order to determine the available capacity of waste energy and to establish the dimension of the cogeneration system it was decided to initially conduct balances of matter and energy of a cement production train. For the evaluation and numerical simulation a case study of a national plant was taken. The analysis takes only into account the rotary kiln, the pre roaster, the gas cooler or conditioner, the cooler of clinker and the separators or dust recuperators. In this study the electrical mills nor the systems that operate all over the plant have been taken in consideration. The results show that in general a high potential of co-generation exists since in some cases the heat losses can reach up to a 50% of the calorific energy input. The capacity of electrical generation by means of a steam turbine when taking advantage of a fraction (in the order of 60%) the residual heat, can be between 200 and 300 watts per kilogram of clinker produced. In conclusion, when recovering by means of appropriate heat exchangers for each one of the mentioned equipment the wasted energy and a network of heat interchange optimized by means of modern technologies an important part of the electrical energy that a cement mill uses can be generated. The method used has been very attractive and with the possibility of applying it to any cement mill and thus evaluate the potentials of energy co-generation. [Spanish] En el presente trabajo, se realizo el diseno de un sistema de cogeneracion aprovechando las corrientes termicas de desecho en una industria de fabricacion de cemento. Los costos por concepto de

  15. Improving the CO2 performance of cement, part III : The relevance of industrial symbiosis and how to measure its impact

    OpenAIRE

    2015-01-01

    Cement production contributes to extensive CO2 emissions. However, the climate impact can vary significantly between different production systems and different types of cement products. The market is dominated by ordinary Portland cement, which is based on primary raw materials and commonly associated with combustion of vast amounts of fossil fuels. Therefore, the production of Portland cement can be described as a rather linear process. But there are alternative options, for example, involvi...

  16. Assessment of radiological hazards of naturally occurring radioactive materials in cement industry.

    Science.gov (United States)

    Aslam, Muhammad; Gul, Rahmat; Ara, Tauseef; Hussain, Manzur

    2012-09-01

    A study on the radiological hazard in Portland cement due to the presence of naturally occurring radioactive materials is being carried out. The Portland cement manufactured in the Islamabad/Rawalpindi region of Pakistan, intermediate products (clinker) and the various raw materials which compose the product have been analysed for (226)Ra, (232)Th and (40)K using a gamma spectrometry system with a N-type high-purity germanium detector of 80 % relative efficiency. From the measured gamma ray spectra, specific activities were determined. The mean values of the total specific activity of (226)Ra, (232)Th and (40)K are 34.2±11.9, 29.1±3.6 and 295.1±66.9 Bq kg(-1), respectively in Portland cement, 28.4±8.7, 11.3±1.7 and 63.1±17.3 Bq kg(-1), respectively in lime stone, 8.2±1.9, 16.2±3.9 and 187.7±53.2 Bq kg(-1), respectively in gypsum, 34.7±13.1, 41.2±6.7 and 187.6±17.2 Bq kg(-1), respectively in clay, 41.1±11.8, 39.3±6.9 and 195.1±29.2 Bq kg(-1), respectively in latrite and 51.1±18.2, 23.2±1.2 and 258.4±15.3 Bq kg(-1), respectively in clinker. The radium equivalent activities (Ra(eq)), external hazard index (H(ex)), internal hazard index (H(in)), absorbed dose rate in air (D) and annual effective dose rate (E(eff)) were also determined. The measured activity concentrations for these radio nuclides and radiological indices were compared with the reported national and international data. All these measured values are comparable with the worldwide data reported in UNSCEAR publications.

  17. Lime mud from cellulose industry as raw material in cement mortars

    Directory of Open Access Journals (Sweden)

    Modolo, R. C.E.

    2014-12-01

    Full Text Available This study reports the use of lime mud (LM in cement-based-mortars. Lime mud is a waste generated in the production of cellulose by the kraft mill process. It is mainly composed of CaCO3, a small amount of magnesium carbonate and other trace minerals. Mortars were prepared by adding different amounts of LM (10, 20 and 30% by weight of cement in dry weight. The mortar compositions were evaluated through rheology and flow table measurements, assuring that all the samples exhibited adequate conditions for testing in both equipments. The hardened state properties were also evaluated through mechanical strengths at 7, 28 and 90 days of curing. Following a waste management solution perspective, this work intend to provide a general evaluation of LM application in cement based mortars, looking at both fresh and hardened properties in order to guarantee that the final application requirements are not hindered.Este estudio revela el uso de lodo de carbonato (LM en morteros de cemento. El LM es un residuo compuesto principalmente por CaCO3 generado en la producción de pasta de papel por el método Kraft. Los morteros se prepararon a partir de la adición de diferentes niveles de LM (10, 20 y 30% en peso de cemento en peso seco. Las composiciones de los morteros fueron caracterizadas através de mediciones de reología de mesa y de flujo, asegurando que las muestras exhibían condiciones adecuadas para su caracterización en ambos equipamientos. Las propiedades en estado endurecido también se evaluaron através de resistencias mecánicas a los 7, 28 y 90 días de cura. Con objeto de gestión de residuos, este trabajo tiene la intención de proporcionar una visión general de la aplicación de LM en los morteros, haciendo hincapié en las propiedades con el fin de garantizar que los requisitos para su aplicación final no se vean obstaculizados.

  18. A study on the effect of working capital management on profitability on Cement and Petrochemical industries: Evidence from Tehran Stock Exchange

    Directory of Open Access Journals (Sweden)

    Fatemeh Khaksarian

    2014-07-01

    Full Text Available This paper presents an empirical investigation to study the effect of working capital management on profitability on Cement and Petrochemical industries. The study uses the information of 24 firms from Cement industry and 19 firms from Petrochemical industry listed on Tehran Stock Exchange. There are two independent variables including the ratio of current assets on total assets as well as the ratio of current liabilities on total assets in this survey. In addition, there are two dependent variables including return on assets (ROA and Tobin’s Q. The study also considers firm size, sales’ growth, financial leverage, gross domestic product growth as control variables. Using stepwise regression technique, the study confirms a positive and meaningful relationship between working capital criteria and profitability. In addition, the study confirms that as the ratio of current assets to total assets increases, ROA and Tobin’s Q will be reduced, which means lower profitability would be resulted. In addition, as financial leverage increases, ROA in both industries will reduce while Tobin’s Q will increase in Cement industry and will reduce in Petrochemical industry.

  19. Implementation of industrial waste ferrochrome slag in conventional and low cement castables: Effect of microsilica addition

    Directory of Open Access Journals (Sweden)

    Pattem Hemanth Kumar

    2014-06-01

    Samples with decreasing cement content 15–05 wt.% were formulated in combination of both slag and calcined bauxite as matrix components. Effects of varying 0–10 wt.% microsilica as a micro-fine additive in these castables were investigated in this work. Pore filling properties of microsilica improved apparent porosity and bulk density. Phase analysis through X-ray diffraction techniques demonstrates successful formation of spinel and mullite crystalline phases. Mechanical behavior was evaluated through cold crushing strength and residual cold crushing strength after five consecutive water quenching cycles. Scanning electron microscopy measurements were carried out in order to better understand the packing density and reaction mechanisms of fired castables. Slag containing castables portrays good thermal properties such as thermal shock resistance, permanent linear change and pyrometric cone equivalent.

  20. Solid recovered fuels in the cement industry--semi-automated sample preparation unit as a means for facilitated practical application.

    Science.gov (United States)

    Aldrian, Alexia; Sarc, Renato; Pomberger, Roland; Lorber, Karl E; Sipple, Ernst-Michael

    2016-03-01

    One of the challenges for the cement industry is the quality assurance of alternative fuel (e.g., solid recovered fuel, SRF) in co-incineration plants--especially for inhomogeneous alternative fuels with large particle sizes (d95⩾100 mm), which will gain even more importance in the substitution of conventional fuels due to low production costs. Existing standards for sampling and sample preparation do not cover the challenges resulting from these kinds of materials. A possible approach to ensure quality monitoring is shown in the present contribution. For this, a specially manufactured, automated comminution and sample divider device was installed at a cement plant in Rohožnik. In order to prove its practical suitability with methods according to current standards, the sampling and sample preparation process were validated for alternative fuel with a grain size >30 mm (i.e., d95=approximately 100 mm), so-called 'Hotdisc SRF'. Therefore, series of samples were taken and analysed. A comparison of the analysis results with the yearly average values obtained through a reference investigation route showed good accordance. Further investigations during the validation process also showed that segregation or enrichment of material throughout the comminution plant does not occur. The results also demonstrate that compliance with legal standards regarding the minimum sample amount is not sufficient for inhomogeneous and coarse particle size alternative fuels. Instead, higher sample amounts after the first particle size reduction step are strongly recommended in order to gain a representative laboratory sample.

  1. Tendencias organizacionales de las empresas.

    OpenAIRE

    Derlisiret Rincón M.; María Gracia Romero

    2002-01-01

    El propósito de este trabajo es analizar la evolución de los modelos organizacionales utilizados por las empresas durante los siglos XX y XXI, a la vez que se intenta establecer las posibles tendencias para las empresas del futuro. Para ello, se caracterizan los modelos con base en la clasificación correspondiente a las visiones: mecanicista, naturista y ecologista de la organización. En tal sentido, se realiza una investigación descriptiva-documental a partir de la revisión de im...

  2. Discussion on the Technical of Total Nitrogen Removal in Cement Industry%水泥行业脱硝工艺技术的探讨

    Institute of Scientific and Technical Information of China (English)

    曾佳敏; 邓燕琳

    2012-01-01

    "十二五"期间,国家将氮氧化物列为大气污染物总量控制约束性指标。其中,水泥行业是氮氧化物减排的重点领域之一,新型干法水泥窑要进行低氮燃烧技术改造,新建水泥生产线要安装效率不低于60%的脱硝设施。文章根据目前水泥行业现状,探讨应相应匹配的脱硝工艺技术。%The "12th Five-Year Plan",the state will nitrogen oxide as the total control of air pollutant binding targets.Among them,the cement industry is one of the key fields of nitrogen oxide emission,cement kiln to low nitrogen combustion technology,a new cement production line to install the efficiency of not less than 60 % of the DeNOx facility.According to the current situation of cement industry,the corresponding matching denitration technology.

  3. ECOLOGICAL STATUS AND DEVELOPMENT DIRECTIONS OF CEMENT INDUSTRY IN CHINA%我国水泥工业“生态化”的研究现状和发展趋势

    Institute of Scientific and Technical Information of China (English)

    郭随华; 翁端; 陈益民

    2001-01-01

    Ecological status and development directions of cement industry in China are discussed in this paper. To improve the ecological situation of the cement industry, the structure of products and the structure of the cement industry should be optimized. These optimizations include improvement of some small-scale cement plants to decrease the whole pollution level of the cement industry. Furthermore, researches on high reactive clinker, high reactive fine admixture of concrete and low-calcium series cement should be emphasized, by which the ecological design of cement, to reduce consumption and pollution of cement production and to improve the utilization efficiency of waste in cement production, can be realized. To produce low-calcium cement such as HBC would be benefit to the ecological production of cement because the clinker can be burned in a relatively low temperature and can be prepared with many low quality raw materials. The cement made from high reactive clinker can u utilize more wastes than traditional cement of the same grade. The cement containing no clinker or only a small amount of clinker is a typical kind of ecological cement. In addition, many researches also showed that the cement production could also be applied to environment protection such as soil upgrading or the use of domestic wastes as fuels in clinker burning.%分析探讨了中国水泥工业“生态化”的研究现状及发展趋势。为提高我国水泥工业发展的生态化水平,必须调整我国水泥工业的产业结构和产品结构,将高性能水泥熟料、高活性细掺料及低钙水泥系列熟料作为今后的研究重点,提高水泥中工业废弃物的利用效率,进行水泥产品生态化设计,以实现水泥生产的低消耗和低污染。

  4. Technology Roadmaps: Cement

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2009-07-01

    To support its roadmap work focusing on key technologies for emissions reductions, the International Energy Agency (IEA) also investigated one particular industry: cement. Cement production includes technologies that are both specific to this industry and those that are shared with other industries (e.g., grinding, fuel preparation, combustion, crushing, transport). An industry specific roadmap provides an effective mechanism to bring together several technology options. It outlines the potential for technological advancement for emissions reductions in one industry, as well as potential cross-industry collaboration.

  5. Cement Mason's Curriculum. Instructional Units.

    Science.gov (United States)

    Hendirx, Laborn J.; Patton, Bob

    To assist cement mason instructors in providing comprehensive instruction to their students, this curriculum guide treats both the skills and information necessary for cement masons in commercial and industrial construction. Ten sections are included, as follow: related information, covering orientation, safety, the history of cement, and applying…

  6. Reducing cement's CO2 footprint

    Science.gov (United States)

    van Oss, Hendrik G.

    2011-01-01

    The manufacturing process for Portland cement causes high levels of greenhouse gas emissions. However, environmental impacts can be reduced by using more energy-efficient kilns and replacing fossil energy with alternative fuels. Although carbon capture and new cements with less CO2 emission are still in the experimental phase, all these innovations can help develop a cleaner cement industry.

  7. Tendencias organizacionales de las empresas.

    Directory of Open Access Journals (Sweden)

    Derlisiret Rincón M.

    2002-01-01

    Full Text Available El propósito de este trabajo es analizar la evolución de los modelos organizacionales utilizados por las empresas durante los siglos XX y XXI, a la vez que se intenta establecer las posibles tendencias para las empresas del futuro. Para ello, se caracterizan los modelos con base en la clasificación correspondiente a las visiones: mecanicista, naturista y ecologista de la organización. En tal sentido, se realiza una investigación descriptiva-documental a partir de la revisión de importantes aportes sobre las nuevas formas organizacionales, evolución y principios de las empresas. Los resultados revelan que la supervivencia de una empresa en contextos turbulentos como los actuales dependerá de variables como: rapidez, calidad, eficiencia, espontaneidad, desestandarización, flexibilidad e innovación. Se concluye que la tendencia es a la ausencia de estructuras organizacionales, formales y rígidas.

  8. The Materials and Energy Potential Method for the quantitative distincion between Valorization and Elimination in the Cement Industry

    NARCIS (Netherlands)

    Zeevalkink, J.A.; Alkemade, M.M.C.

    1996-01-01

    This report proposes a quantitative method to distinguish between valorization and elimination of waste in a cement kiln. Examples are calculated to illustrate the consequences of the developed approach. Valorization is defined as the processing of a waste in a cement kiln to substi-tute raw materia

  9. Preparation of Super Composite Cement with a Lower Clinker Content and a Larger Amount of Industrial Wastes

    Institute of Scientific and Technical Information of China (English)

    HE Zhen; LIANG Wen-quan; LI Bei-xing; LI Xiang-guo

    2002-01-01

    The effects of the grinding mode,fineness, gypsum kinds and dosage, mix proportions on properties of the composite cements consisting of slag,fly ash, limestone and a lower content clinker were investigated,respectively. The results show that when the proportions among slag, fly ash and limestone are appropriate, the grinding technology and system are reasonable, the optimized gypsums and additives are effective, the 52.5 R grade cement (52.5 R grade cement means a higher strength than 52.5 at early age ) can be prepared by clinker dosage of 50% in weight, the 42.5R or 42.5,32.5 grade composite cement containing 40% and 30% clinker also may be made, respectively. Moreover, the high performance concrete prepared from the above composite cements was studied experimentally.

  10. Discussion on the application of the oxygen enriched combustion technology in cement industry%富氧燃烧技术在水泥企业应用的探讨

    Institute of Scientific and Technical Information of China (English)

    干志强

    2014-01-01

    通过对国内几家采用富氧燃烧技术企业的考察,结合水泥企业的现状,提出了富氧燃烧技术在水泥行业应用的一些建议。%Through the use of several domestic company visits,combined with the status of the cement industry,proposed some recommendations of the applications in the cement industry.

  11. Maintenance Free and Sustainable High-Level Control in Cement and Mining Industry

    DEFF Research Database (Denmark)

    Hansen, Ole Fink

    2009-01-01

    of machinery, and reconstruction of the plant etc. Therefore, in order to keep a constant, high performance, the high-level control system requires regular maintenance by means of expert personnel readjusting and modifying the algorithm, which is resource demanding. The aim of this Ph.D. project is to minimize...... or eliminate the amount of resources needed to keep a high performance. Current high-level control algorithms are sophisticated and complex software. An analysis of such algorithms shows that only 10% of the source code can be considered implementation of control theory. The remaining 90% handles other tasks...... chosen to focus on the remaining 90% of the algorithm which still require manual modifications to cope with a changed process. Although this issue has gained limited attention from academia so far it is well recognized by the industry. In the process of maintaining an algorithm it has turned out...

  12. Cement industry structure adjustment and macro regulation and control%水泥结构调整与宏观调控

    Institute of Scientific and Technical Information of China (English)

    牛建国

    2004-01-01

    This article recalled the background of our national economy development in 2003, namely our GDP increase, total amount of import and export,industrial increase scale all reached quite high level and at the same time showed such problems like excessive large fixed assets investment scale and coal, electricity, oil, transport and price in economic operation.The article further expounds on the principle, stress and measure of macro regulation and control as well as the good trend of our general national economy operation in the first half of this year.This article also made introduction about relative state policy concerning cement industry development.

  13. Process development for utilizing asbestos cement waste in rotary kilns for the cement industry. Final report; Erarbeitung eines Verfahrens zur stofflichen Verwertung von zementgebundenen Asbestprodukten in Drehrohroefen fuer die Zementindustrie. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Schlegel, R.; Kieser, J.; Kraehner, A.

    1999-11-01

    The law for recycling and waste demands the utilization also for waste of asbestos cement (ac). The procedure of thermal utilization of ac in the flame of a rotary cement kiln was developed and patented by the research institute IBU-tec Weimar, Germany. The ac-material has to be pre-pulverized and grinded to a degree of fineness of R{sub 90}<15%. Considerations of safety engineering lead to the idea of common fine grinding of old oil (oo) and ac. This new procedure was searched in FuE-project in 1998/99 (financial support by BMBF). A mash of ac and oo was generated as a utilization product ready for firing which was injected into the flame of the rotary cement kiln. This particles of ac smelt to spherical shaped particles at a temperature above 1500 C. They were utilized by clinker formation. The material and gas stream leaving the kiln does not contain fibres of asbestos. This was demonstrated in a small equipment burning test. The industrial realization concerning cement plant Ruedersdorf, near Berlin, was searched, technologically described and safety engineeringly and financially assessed by a project study. Process-technical and financial advantages were seen for the dry fine grinding. The wet fine grinding with old oil could be used in cement plants using old oil as fuel. (orig.) [German] Das Kreislaufwirtschafts- und Abfallgesetz (1994) fordert u.a. die stoffliche Verwertung auch fuer Asbestzementabfaelle (AZ). Das vom Institut fuer Baustoff- und Umweltschutz-Technologie Weimar 1995 entwickelte und patentierte Verfahren zur thermischen Verwertung von AZ in der Flamme eines Zementdrehrohrofens erfuellt diese Forderung. Das AZ-Material muss vorzerkleinert und bis zur Rohmehlfeinheit (R{sub 90}<15%) feingemahlen werden. Sicherheitstechnische Ueberlegungen fuehrten zu der Idee, die Feinmahlung zusammen mit Altoel (AOe) zu erproben. Diese Verfahrensvariante wurde im Rahmen eines FuE-Projektes 1998/99 untersucht (finanzielle Foerderung durch das BMBF). Als

  14. GESTIÓN HUMANA: TENDENCIAS Y PERSPECTIVAS

    OpenAIRE

    JUAN GUILLERMO SALDARRIAGA RÍOS

    2008-01-01

    En este artículo se hace referencia a las tendencias y las perspectivas de gestión humana que se imponen en el mundo en la actualidad y que, a su manera, pretenden optimizar la administración del personal de la organización y contribuir al desarrollo e incremento de la productividad y la competitividad. Mediante la realización de un Estado del Arte se logran determinar algunas de las tendencias más relevantes en la actualidad y se concluye que, cada vez con mayor fuerza, dichas tendencias se ...

  15. Fundamental properties of industrial hybrid cement: utilization in ready-mixed concretes and shrinkage-reducing applications

    Directory of Open Access Journals (Sweden)

    Martauz, P.

    2016-06-01

    Full Text Available Utility properties of novel hybrid cement (H-Cement are influenced by pozzolanic reaction of fly ash, latent hydraulic reaction of metallurgical slag together with the alkali activation of inorganic geopolymer based on precipitated waste water coming from bauxite residues. Content of Portland cement clinker is at maximum of 20 mass %, the remaining portion consists of inorganic geopolymer. Up to 80% of CO2 emissions are saved by H-Cement manufacture compared to ordinary Portland cement (OPC. No heat treatment or autoclaving is needed at H-Cement production. The field application of H-Cement is performed by the same way than that of common cements listed in EN 197-1, and is also connected with highly efficient recovery and safe disposal of red mud waste. H-Cement is suitable for ready-mixed concretes up to C30/37 strength class and is specified by beneficial shrinkage-reducing property of the concrete kept in long dry-air cure opposite to common cements.Las propiedades de un nuevo cemento híbrido (cemento-H vienen determinadas por la reaccion puzolánica de cenizas volantes, la hidráulica latente de las escorias metalúrgicas y la activación alcalina mediante las aguas residuales generadas por el tratamiento de la bauxita para dar un geopolímero inorgánico. La proporción máxima de clínker de cemento en este nuevo material es del 20%, y por ello, en su fabricación se emite hasta un 80% menos de CO2 que en la producción del cemento portland (OPC. El cemento-H se prepara sin necesidad de tratamiento térmico ni de estancia en autoclave y su aplicación es la misma que los cementos convencionales definidos en la norma EN 197-1. Por otra parte, su fabricación supone la recuperación y la valorización segura de los lodos rojos de bauxita. El cemento-H es apto para la preparación de hormigones premezclados hasta la categoría C30/37, presentando el nuevo material, además, una menor retracción que los cementos convencionales, por lo que su

  16. Lung function reduction and chronic respiratory symptoms among workers in the cement industry: a follow up study

    Directory of Open Access Journals (Sweden)

    Zeleke Zeyede K

    2011-11-01

    Full Text Available Abstract Background There are only a few follow-up studies of respiratory function among cement workers. The main aims of this study were to measure total dust exposure, to examine chronic respiratory symptoms and changes in lung function among cement factory workers and controls that were followed for one year. Methods The study was conducted in two cement factories in Ethiopia. Totally, 262 personal measurements of total dust among 105 randomly selected workers were performed. Samples of total dust were collected on 37-mm cellulose acetate filters placed in closed faced Millipore-cassettes. Totally 127 workers; 56 cleaners, 44 cement production workers and 27 controls were randomly selected from two factories and examined for lung function and interviewed for chronic respiratory symptoms in 2009. Of these, 91 workers; 38 cement cleaners (mean age 32 years, 33 cement production workers (36 years and 20 controls (38 years were examined with the same measurements in 2010. Results Total geometric mean dust exposure among cleaners was 432 mg/m3. The fraction of samples exceeding the Threshold Limit Value (TLV of 10 mg/m3 for the cleaners varied from 84-97% in the four departments. The levels were considerably lower among the production workers (GM = 8.2 mg/m3, but still 48% exceeded 10 mg/m3. The prevalence of all the chronic respiratory symptoms among both cleaners and production workers was significantly higher than among the controls. Forced Expiratory Volume in one second (FEV1 and FEV1/Forced Vital Capacity (FEV1/FVC were significantly reduced from 2009 to 2010 among the cleaners (p Conclusions The high prevalence of chronic respiratory symptoms and reduction in lung function is probably associated with high cement dust exposure. Preventive measures are needed to reduce the dust exposure.

  17. Portland cement-blast furnace slag blends in oilwell cementing applications

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, D.T.; DiLullo, G.; Hibbeler, J. [and others

    1995-12-31

    Recent investigations of blast furnace slag cementing technologies. have been expanded to include Portland cement/blast furnace slag blends. Mixtures of Portland cement and blast furnace slag, while having a long history of use in the construction industry, have not been used extensively in oilwell cementing applications. Test results indicate that blending blast furnace slag with Portland cement produces a high quality well cementing material. Presented are the design guidelines and laboratory test data relative to mixtures of blast furnace slag and Portland cements. Case histories delineating the use of blast furnace slag - Portland cement blends infield applications are also included.

  18. Penetration of natural gas in industrial processes for direct burning: the case of ceramics, cement and glass industries; Penetracao do gas natural em processos industriais de queima direta: caso das industrias ceramica, cimento e vidro

    Energy Technology Data Exchange (ETDEWEB)

    Berni, Mauro Donizeti; Leite, Alvaro A. Furtado [Universidade Estadual de Campinas (UNICAMP), SP (Brazil); Dorileo, Ivo Leandro [Universidade Federal do Mato Grosso (NIEPE/UFMT), Cuiaba, MT (Brazil). Nucleo Interdisciplinar de Estudos em Planejamento Energetico; Bajay, Sergio Valdir [Universidade estadual de Campinas (FEM/UNICAMP), SP (Brazil). Fac. de Engenharia Mecanica. Dept. de Energia], e-mail: bajay@fem.unicamp.com.br

    2008-07-01

    Industrial sector can use the natural gas (NG) as raw material, as fuel and in co-generation. The NG as fuel is used, predominantly, to produce heat in the Brazilian industries. That rate, both main forms of industrial use of the NG are its direct burning in kilns - when the direct contact is had with the product - and the supply of process heat through boilers, for instance. Direct burning is used in the ceramic, cement and glass industries. This work discuss the penetration opportunity of the NG in the direct burning regarding the fuel oil and other energy that it can substitute, the environmental effects and the co-generation possibilities in each one of the analyzed industrial blanches in this work. (author)

  19. Analysis on Denitrification Measures and Applications in Cement Industry%水泥行业降氮脱硝措施及工程应用浅析

    Institute of Scientific and Technical Information of China (English)

    汪好芬; 查小明

    2012-01-01

    Cement industry is the second largest nitrogen oxides( NOx )emission source of China's industrial enterprise. NOx emissions control is the key for energy saving and emission reduction during the "12th Five - Year Plan" period. The implementa- tion of denitrification policy and promotion of discharge standards will reduce the NOx emission. Through reviews on common deni- gration technologies and comparison of their applications, this paper briefly analyzed the status of NOx emissions from cement in- dustry. Results show that it is feasible and urgent to enhance the NOx emission standards in cement industry. Some proposals in the application of denigration technology were put forward.%水泥行业是中国工业企业中第二大氮氧化物排放源,对水泥行业进行氮氧化物控制是中国"十二五"节能减排工作的重点,实施强制脱硝政策和提高排放标准有利于水泥行业减少氮氧化物排放。通过综述几种常用脱硝技术的原理和应用比较,简要分析中国当前水泥行业氮氧化物排放现状,得出提高水泥行业氮氧化物排放标准的可行性和迫切性,同时对脱硝技术应用提出建议。

  20. Refuse derived fuel (RDF) plasma torch gasification as a feasible route to produce low environmental impact syngas for the cement industry.

    Science.gov (United States)

    López-Sabirón, Ana M; Fleiger, Kristina; Schäfer, Stefan; Antoñanzas, Javier; Irazustabarrena, Ane; Aranda-Usón, Alfonso; Ferreira, Germán A

    2015-08-01

    Plasma torch gasification (PTG) is currently researched as a technology for solid waste recovery. However, scientific studies based on evaluating its environmental implications considering the life cycle assessment (LCA) methodology are lacking. Therefore, this work is focused on comparing the environmental effect of the emissions of syngas combustion produced by refuse derived fuel (RDF) and PTG as alternative fuels, with that related to fossil fuel combustion in the cement industry. To obtain real data, a semi-industrial scale pilot plant was used to perform experimental trials on RDF-PTG.The results highlight that PTG for waste to energy recovery in the cement industry is environmentally feasible considering its current state of development. A reduction in every impact category was found when a total or partial substitution of alternative fuel for conventional fuel in the calciner firing (60 % of total thermal energy input) was performed. Furthermore, the results revealed that electrical energy consumption in PTG is also an important parameter from the LCA approach.

  1. Causality between energy consumption and output growth in the Indian cement industry: An application of the panel vector error correction model (VECM)

    Energy Technology Data Exchange (ETDEWEB)

    Kumar Mandal, Sabuj, E-mail: sabujecon@gmail.co [T.A. Pai Management Institute (TAPMI), Manipal 576104, Karnataka (India); Madheswaran, S. [Institute for Social and Economic Change, Bangalore 560072, Karnataka (India)

    2010-11-15

    The aim of this paper is to examine the existence and direction of the causal relationship between energy consumption and output growth in the Indian cement industry for the period 1979-80 to 2004-05. The most recently developed panel unit root, a heterogeneous panel cointegration and panel-based error correction model, is applied within a multivariate framework. The empirical results confirm a positive, long-run cointegrated relationship between output and energy consumption when heterogeneous state effects are taken into account. We also found a long-run, bi-directional relationship between energy consumption and output growth in the Indian cement industry for the study period, implying that an increase in energy consumption directly affects the growth of this sector and that growth stimulates further energy consumption. These empirical findings imply that energy consumption and output are jointly determined and affect each other. The empirical evidence also suggests the implementation of energy conservation policies oriented toward improving energy-use efficiency to avoid any negative impacts of the conservation policies on the growth of this industry.

  2. Causality between energy consumption and output growth in the Indian cement industry. An application of the panel vector error correction model (VECM)

    Energy Technology Data Exchange (ETDEWEB)

    Kumar Mandal, Sabuj [T.A. Pai Management Institute (TAPMI), Manipal 576104, Karnataka (India); Madheswaran, S. [Institute for Social and Economic Change, Bangalore 560072, Karnataka (India)

    2010-11-15

    The aim of this paper is to examine the existence and direction of the causal relationship between energy consumption and output growth in the Indian cement industry for the period 1979-80 to 2004-05. The most recently developed panel unit root, a heterogeneous panel cointegration and panel-based error correction model, is applied within a multivariate framework. The empirical results confirm a positive, long-run cointegrated relationship between output and energy consumption when heterogeneous state effects are taken into account. We also found a long-run, bi-directional relationship between energy consumption and output growth in the Indian cement industry for the study period, implying that an increase in energy consumption directly affects the growth of this sector and that growth stimulates further energy consumption. These empirical findings imply that energy consumption and output are jointly determined and affect each other. The empirical evidence also suggests the implementation of energy conservation policies oriented toward improving energy-use efficiency to avoid any negative impacts of the conservation policies on the growth of this industry. (author)

  3. Economic Operating Status of Chinese Cement Industry in 2002 and Its Prospect for 2003%水泥工业2002年经济运行情况及2003年展望

    Institute of Scientific and Technical Information of China (English)

    曾学敏

    2003-01-01

    @@ 1 Economic Operating Status of Cement Industry in 2002 1.1 Firnal Status of Various Economic Indexes in 2002(according to monthly reports ) The statistical data of all state - owned industrial enterprises and non - state - owned ones with an annual sales income of more than 5 million yuan (including 5 million yuan) for each of them are as follows:

  4. Use of precalciners to remove alkali from raw materials in the cement industry. Final report, July 1978-July 1980

    Energy Technology Data Exchange (ETDEWEB)

    Gartner, E.M.

    1980-07-01

    The objective of this work was to develop an efficient means of removing alkali metal compounds (alkalies) from high-alkali aluminosilicate raw materials of the type commonly used as part of cement raw mixes in order to increase the energy efficiency of cement manufacture. The intention of this project was to determine whether the high-alkali raw materials could be pyroprocessed separately to remove the alkalies before they entered the rotary kiln, where they would be mixed with the other raw feed components. If this could be achieved, considerable savings could be made in the energy required to remove alkalies, compared to conventional methods in which the cement raw mix must be treated as a whole. Two different methods of alkali removal were examined, namely, vaporization of alkalies at relatively low temperatures; and alkali-rich melt separation at relativey high temperatures. The results showed that the removal of alkalies by pyroprocessing of high-alkali raw feed components separate from the other cement raw mix components is not likely to be a practical alternative to the best available conventional precalciner technology. (LCL)

  5. Evaluation of a lime-mediated sewage sludge stabilisation process. Product characterisation and technological validation for its use in the cement industry.

    Science.gov (United States)

    Rodríguez, N Husillos; Granados, R J; Blanco-Varela, M T; Cortina, J L; Martínez-Ramírez, S; Marsal, M; Guillem, M; Puig, J; Fos, C; Larrotcha, E; Flores, J

    2012-03-01

    This paper describes an industrial process for stabilising sewage sludge (SS) with lime and evaluates the viability of the stabilised product, denominated Neutral, as a raw material for the cement industry. Lime not only stabilised the sludge, raised the temperature of the mix to 80-100°C, furthering water evaporation, portlandite formation and the partial oxidation of the organic matter present in the sludge. Process mass and energy balances were determined. Neutral, a white powder consisting of portlandite (49.8%), calcite (16.6%), inorganic oxides (13.4%) and organic matter and moisture (20.2%), proved to be technologically apt for inclusion as a component in cement raw mixes. In this study, it was used instead of limestone in raw mixes clinkerised at 1400, 1450 and 1500°C. These raw meals exhibited greater reactivity at high temperatures than the limestone product and their calcination at 1500°C yielded clinker containing over 75% calcium silicates, the key phases in Portland clinker. Finally, the two types of raw meal (Neutral and limestone) were observed to exhibit similar mineralogy and crystal size and distribution.

  6. GESTIÓN HUMANA: TENDENCIAS Y PERSPECTIVAS

    Directory of Open Access Journals (Sweden)

    JUAN GUILLERMO SALDARRIAGA RÍOS

    2008-01-01

    Full Text Available En este artículo se hace referencia a las tendencias y las perspectivas de gestión humana que se imponen en el mundo en la actualidad y que, a su manera, pretenden optimizar la administración del personal de la organización y contribuir al desarrollo e incremento de la productividad y la competitividad. Mediante la realización de un Estado del Arte se logran determinar algunas de las tendencias más relevantes en la actualidad y se concluye que, cada vez con mayor fuerza, dichas tendencias se sustentan en discursos que pretenden "rescatar" al ser humano dentro de la organización, lo que no necesariamente se traduce en los procesos de gestión humana que se realizan en las organizaciones nacionales e internacionales.

  7. Cement Formation

    DEFF Research Database (Denmark)

    Telschow, Samira; Jappe Frandsen, Flemming; Theisen, Kirsten

    2012-01-01

    Cement production has been subject to several technological changes, each of which requires detailed knowledge about the high multiplicity of processes, especially the high temperature process involved in the rotary kiln. This article gives an introduction to the topic of cement, including...... an overview of cement production, selected cement properties, and clinker phase relations. An extended summary of laboratory-scale investigations on clinkerization reactions, the most important reactions in cement production, is provided. Clinker formations by solid state reactions, solid−liquid and liquid...

  8. Trends in the location of the European car industry from an analysis of trade in parts and components; Tendencias en la localizacion de la industria Europea de automocion. Un analisis a partir del comercio de partes y componentes

    Energy Technology Data Exchange (ETDEWEB)

    Blazquez Gomez, L.; Diaz Mora, C.; Gandoy Juste, R.

    2010-07-01

    The object of this paper is to study the changes in location and specialization in the European automotive industry since the mid-nineties. The analysis is based on the examination of trade flows, distinguishing between final goods and parts and components, and on the delimitation of revealed comparative advantages for those countries leading the European industry. The results show the significance of the European production networks and the increasing new Eastern member countries role in them. Besides, they allow us to establish the main participant countries competitive position in those networks. As far as the Spanish industry is concerned, two aspects must be pointed out. On the one hand, the decrease in the advantages in cars assembly although the specialization in industrial motor vehicles maintains. And on the other hand, the competitive capacity showed by some auxiliary car industries. (Author) 22 refs.

  9. POZZOLAN AND CEMENTS WITH POZZOLAN

    Directory of Open Access Journals (Sweden)

    Hasan KAPLAN

    1995-02-01

    Full Text Available Cement, one of the basic material of construction engineering, has an important place in view of strength and cost of structures. Cement consumption is increasing parallel to development of building construction sector. For cement producers, minimal cost is desired by using new and economical material sources. On the other hand, the controllers and contractors need cheaper, safer and higher strength materials. From this respect cement industry tends to use cement with pozzolan. In Türkiye, cement with pozzolan is produced by adding the pozzolan, which has a large reservoir in the country, in cement in sertain amount. However this type of cement is consumed in the construction sector, sortage of scientific investigation and speculative news on the subject.are worried the users and producers. In this paper, prior to an experimental study on the cements having pozzolan additive, historical development of pozzolan, reservoir of Turkiye, and comparison with portland cement is carried out. Advantages and disadvantages of pozzolan are also discussed in some points.

  10. CO2 Capture by Cement Raw Meal

    DEFF Research Database (Denmark)

    Pathi, Sharat Kumar; Lin, Weigang; Illerup, Jytte Boll

    2013-01-01

    The cement industry is one of the major sources of CO2 emissions and is likely to contribute to further increases in the near future. The carbonate looping process has the potential to capture CO2 emissions from the cement industry, in which raw meal for cement production could be used...... as the sorbent. Cyclic experiments were carried out in a TGA apparatus using industrial cement raw meal and synthetic raw meal as sorbents, with limestone as the reference. The results show that the CO2 capture capacities of the cement raw meal and the synthetic raw meal are comparable to those of pure limestone...... that raw meal could be used as a sorbent for the easy integration of the carbonate looping process into the cement pyro process for reducing CO2 emissions from the cement production process....

  11. The Green Design of the Belt Conveyor for Cement Industry%浅谈水泥工业用带式输送机的绿色设计

    Institute of Scientific and Technical Information of China (English)

    黄兰

    2015-01-01

    带式输送机广泛应用于水泥工业的多个环节,在转运和输送粉粒状物料的过程中,易产生扬尘和洒落,造成粉尘污染。为了有效降低粉尘污染,引入绿色设计理念,介绍相关粉尘控制的绿色设计方法、技术和措施,实现带式输送机的清洁运输。%Belt conveyor is widely used in cement industry .When transferring the powdery or particulate material ,dust pollution is caused by the fugitive dust .In order to reduce dust pollution ,introducing the concept of green design ,including green design methods ,techniques and measures for dust control .

  12. ¿Existen hoy tendencias educativas?

    OpenAIRE

    Contreras, José Miguel; Hernández, Fernando; Puig, Josep M.; Rué, Joan; Trilla, Jaume; Carbonell, Jaume

    1996-01-01

    En este artículo introductorio se comenta el significado de las tendencias educativas, subrayando las dificultades hoy, a diferencia de antaño, de ofrecer una radiografía nítida de aquéllas. A continuación, se señalan los criterios de clasificación que se han seguido en la elaboración de esta monografía.

  13. Industry

    Energy Technology Data Exchange (ETDEWEB)

    Bernstein, Lenny; Roy, Joyashree; Delhotal, K. Casey; Harnisch, Jochen; Matsuhashi, Ryuji; Price, Lynn; Tanaka, Kanako; Worrell, Ernst; Yamba, Francis; Fengqi, Zhou; de la Rue du Can, Stephane; Gielen, Dolf; Joosen, Suzanne; Konar, Manaswita; Matysek, Anna; Miner, Reid; Okazaki, Teruo; Sanders, Johan; Sheinbaum Parado, Claudia

    2007-12-01

    This chapter addresses past, ongoing, and short (to 2010) and medium-term (to 2030) future actions that can be taken to mitigate GHG emissions from the manufacturing and process industries. Globally, and in most countries, CO{sub 2} accounts for more than 90% of CO{sub 2}-eq GHG emissions from the industrial sector (Price et al., 2006; US EPA, 2006b). These CO{sub 2} emissions arise from three sources: (1) the use of fossil fuels for energy, either directly by industry for heat and power generation or indirectly in the generation of purchased electricity and steam; (2) non-energy uses of fossil fuels in chemical processing and metal smelting; and (3) non-fossil fuel sources, for example cement and lime manufacture. Industrial processes also emit other GHGs, e.g.: (1) Nitrous oxide (N{sub 2}O) is emitted as a byproduct of adipic acid, nitric acid and caprolactam production; (2) HFC-23 is emitted as a byproduct of HCFC-22 production, a refrigerant, and also used in fluoroplastics manufacture; (3) Perfluorocarbons (PFCs) are emitted as byproducts of aluminium smelting and in semiconductor manufacture; (4) Sulphur hexafluoride (SF{sub 6}) is emitted in the manufacture, use and, decommissioning of gas insulated electrical switchgear, during the production of flat screen panels and semiconductors, from magnesium die casting and other industrial applications; (5) Methane (CH{sub 4}) is emitted as a byproduct of some chemical processes; and (6) CH{sub 4} and N{sub 2}O can be emitted by food industry waste streams. Many GHG emission mitigation options have been developed for the industrial sector. They fall into three categories: operating procedures, sector-wide technologies and process-specific technologies. A sampling of these options is discussed in Sections 7.2-7.4. The short- and medium-term potential for and cost of all classes of options are discussed in Section 7.5, barriers to the application of these options are addressed in Section 7.6 and the implication of

  14. Modification of Red Mud and Application to Cement Industry%赤泥的改性及其在水泥生产中的应用

    Institute of Scientific and Technical Information of China (English)

    任根宽

    2011-01-01

    The alkali content in the red mud is reduced by neutralization with industrial slag, acidic phosphogypsum.The γ-2CaO·SiO2 with low activity in the red mud is transformed into β-2CaO·SiO2 with high activity by roasting the mixture of red mud and phosphogypsum under some temperature, so the activity of red mud is increased.The results indicate that the red mud modified with the proportion of red mud to phosphogypsum 10∶ 1 , and roasted at 800℃ for 2h and natural cooling, as addition of cement, the favorable effect is achieved.With the comparison of the modified red mud and the red mud, the strength of cement is increased 16% with 45% admixture, physical properties of cement is consonant with 525# the state standard request.%采用酸性工业废渣磷石膏作为赤泥中和剂,降低赤泥中含碱量.通过在一定温度下煅烧赤泥和磷石膏的混合物,使低活性γ-2CaO·SiO2转化为高活性的β-2CaO·SiO2,提高赤泥的活性.结果表明,赤泥与磷石膏按10:1比例混合后,在800℃进行煅烧,保温2h后自然冷却,用改性赤泥作为水泥的混含材,并取的良好效果.在水泥中掺45%的混合材,改性赤泥比赤泥用作混合材时后期强度挺高近16%,水泥的各项物理性能仍能满足525#水泥国标的要求.

  15. Application of Factor Analysis on the Financial Ratios of Indian Cement Industry and Validation of the Results by Cluster Analysis

    Science.gov (United States)

    De, Anupam; Bandyopadhyay, Gautam; Chakraborty, B. N.

    2010-10-01

    Financial ratio analysis is an important and commonly used tool in analyzing financial health of a firm. Quite a large number of financial ratios, which can be categorized in different groups, are used for this analysis. However, to reduce number of ratios to be used for financial analysis and regrouping them into different groups on basis of empirical evidence, Factor Analysis technique is being used successfully by different researches during the last three decades. In this study Factor Analysis has been applied over audited financial data of Indian cement companies for a period of 10 years. The sample companies are listed on the Stock Exchange India (BSE and NSE). Factor Analysis, conducted over 44 variables (financial ratios) grouped in 7 categories, resulted in 11 underlying categories (factors). Each factor is named in an appropriate manner considering the factor loads and constituent variables (ratios). Representative ratios are identified for each such factor. To validate the results of Factor Analysis and to reach final conclusion regarding the representative ratios, Cluster Analysis had been performed.

  16. Use of Fluidized Bed Combustion Ash and Other Industrial Wastes as Raw Materials for the Manufacture of Calcium Sulphoaluminate Cements

    Science.gov (United States)

    Marroccoli, M.; Montagnaro, F.; Pace, M. L.; Telesca, A.; Valenti, G. L.

    Calcium sulphoaluminate cements, mainly composed by 4CaO·3Al2O3·SO3 and 2CaO·SiO2, are special hydraulic binders which require limestone, bauxite and gypsum as natural raw materials for their manufacture. In order to save bauxite and natural gypsum, it has been explored the possibility of using, among the raw mix components, FBC waste together with pulverised coal fly ash or anodization mud and, when necessary, flue gas desulphurization gypsum. Mixtures containing limestone (29-39%), FBC waste (30-44%), pulverised coal fly ash (0-13%) or anodization mud (0-32%), bauxite (0-18%) and flue gas desulphurization gypsum (0-8%) were heated for 2 hours in a laboratory electric oven at temperatures ranging from 1150° to 1300°C. The X-ray diffraction patterns on the burnt products generally showed a good conversion of the reactants and a high selectivity degree towards 4CaO·3Al2O3·SO3, particularly at 1250°C.

  17. 水泥工业CO2减排及利用技术进展%Technical Progress of Emission-reduction and Utilization of Carbon Dioxide in Cement Industry

    Institute of Scientific and Technical Information of China (English)

    马忠诚; 汪澜

    2011-01-01

    Emission-reduction exists potentially in cement industry, which is the key industry for carbon dioxide emission. Carbonate decomposition, fuel combustion and electric power consumption, etc. Which discharge carbon dioxide in cement industry, are introduced. A series of methods for decreasing carbon dioxide emission in cement industry, such as improving energy utilization, using alternative raw materials and fuels, developing new low carbone-mission binding materials, etc. Are expounded. Finally, several technologies for recycling of carbon dioxide, such as separation, capture, storage, fixation, etc. Are suggested.%水泥工业是CO2排放的重点行业,减排潜力巨大.全面介绍了水泥生产中碳酸盐分解、燃料燃烧和电力消耗等方面CO2的排放情况;详细阐述了水泥生产中通过提高能源利用率、使用替代原燃料、开发新型低碳排放的胶凝材料等措施实现CO2减排的方法,提出了对水泥工业CO2排放实施的分离、捕集、封存、固定等回收利用技术.

  18. Effect of the activation of a clay-base paper industry by-product on cement matrix behaviour

    Directory of Open Access Journals (Sweden)

    García, R.

    2008-12-01

    Full Text Available The present study addresses variations in the calcination temperature (600-750 ºC and kiln time (two to five hours applied to activate coated paper waste and their effect on the rheological, physical and mechanical behaviour of cement matrices containing these active additions.The results obtained showed that the conditions under which kaolinite was activated had a direct effect on the subsequent behaviour of the calcined products. At activating temperatures of over 700 ºC, pozzolanic activity and mechanical strength were observed to be lower, setting time shorter and the mortar less workable.El presente trabajo de investigación aborda la influencia de las condiciones de activación (600-750 ºC y 2-5 horas de permanencia en el horno de los lodos de papel procedente de la fabricación de papel estucado en el comportamiento reológico, físico y mecánico de las matrices de cementos elaboradas con este tipo de adiciones activas.Los resultados obtenidos muestran una influencia directa entre las condiciones de activación de la caolinita y el comportamiento posterior de los productos calcinados. Así, en condiciones de activación superiores a 700 ºC se observa una menor actividad puzolánica, tiempo de fraguado más corto, disminución de la trabajabilidad de los morteros mezcla y resistencia mecánica más baja.

  19. Nuevas tendencias en digitalización

    OpenAIRE

    Díaz, Jose Luis

    2009-01-01

    [ES] En esta presentación se explica las nuevas tendencias de digitalización en Servicio Móvil. En concreto las causas de digitalización, así como su proceso y las tecnologías utilizadas para la digitalización. [EN] This presentation explains the new trend of digitization in Field Service. In particular the causes of digitization and its process technologies used for scanning. Comunicación presentada en el 9º Workshop de Rebiun sobre proyectos digitales, Investigación, innovación e info...

  20. Aplicaciones Normas APA y sus tendencias

    OpenAIRE

    Ledesma Ayora, Marco; Muñoz Cajilima, Néstor Xavier

    2016-01-01

    [ES] Este manual fue elaborado en base a las normas APA (American Psychological Association), actualización y el aporte como tendencias, el anhelo es que sea de beneficio para estudiantes, docentes e investigadores que aplican una buena escritura académica. Las normas APA es un conjunto de referencias para la escritura de trabajos, proyectos y publicaciones, proyectando así su validez y confiabilidad, que permiten visibilizar una correcta formalidad en la presentación, pudiendo ser mediado a ...

  1. 76 FR 2832 - National Emission Standards for Hazardous Air Pollutants From the Portland Cement Manufacturing...

    Science.gov (United States)

    2011-01-18

    ... the Portland Cement Manufacturing Industry and Standards of Performance for Portland Cement Plants... (NESHAP) from the Portland Cement Manufacturing Industry and Standards of Performance (NSPS) for Portland Cement Plants. The final rules were published on September 9, 2010. This direct final action...

  2. 75 FR 54969 - National Emission Standards for Hazardous Air Pollutants From the Portland Cement Manufacturing...

    Science.gov (United States)

    2010-09-09

    ... Portland Cement Manufacturing Industry and Standards of Performance for Portland Cement Plants; Final Rule... Hazardous Air Pollutants From the Portland Cement Manufacturing Industry and Standards of Performance for Portland Cement Plants AGENCY: Environmental Protection Agency (EPA). ACTION: Final rule. SUMMARY: EPA...

  3. 77 FR 46371 - National Emission Standards for Hazardous Air Pollutants for the Portland Cement Manufacturing...

    Science.gov (United States)

    2012-08-03

    ... the Portland Cement Manufacturing Industry and Standards of Performance for Portland Cement Plants... Standards for Hazardous Air Pollutants for the Portland Cement Manufacturing Industry and Standards of Performance for Portland Cement Plants,'' which was published in the Federal Register on July 18, 2012....

  4. 76 FR 28318 - National Emission Standards for Hazardous Air Pollutants From the Portland Cement Manufacturing...

    Science.gov (United States)

    2011-05-17

    ... the Portland Cement Manufacturing Industry and Standards of Performance for Portland Cement Plants... Pollutants emitted by the Portland Cement Industry and the New Source Performance Standards for Portland Cement Plants issued under sections 112(d) and 111(b) of the Clean Air Act, respectively. The EPA is...

  5. 76 FR 2860 - National Emission Standards for Hazardous Air Pollutants From the Portland Cement Manufacturing...

    Science.gov (United States)

    2011-01-18

    ... the Portland Cement Manufacturing Industry and Standards of Performance for Portland Cement Plants... of Performance (NSPS) for Portland Cement Plants. The final rules were published on September 9, 2010... Portland Cement Manufacturing Industry Docket, Docket ID No. EPA-HQ-OAR-2002-0051, 1200 Pennsylvania...

  6. The mineralogy and chemistry of cement and cement raw materials In the united arab emirates

    OpenAIRE

    Nasir, Sobhi J. [صبحي جابر نصر; El Etr, H.

    1996-01-01

    The raw materials, clinkers and cements from different cement factories in the United Arab Emirates have been investigated using polarizing microscopy, X-ray diffraction (XRD), Scanning electron microscopy (SEM), and chemical analyses. The chemical and mineralogical analyses indicate that the local raw materials are suitable for cement industry. Geological review shows that there is a good potential for industrial-grade local occurrences of limestone, marl, gypsum and iron oxide, that may be ...

  7. Development of the Portland cement slurries with diatomaceous earth to the oil industry; Desenvolvimento de pastas de cimento Portland com adicao de diatomita para a industria do petroleo

    Energy Technology Data Exchange (ETDEWEB)

    Brito, Roseane A; Melo, Dulce M.A.; Martinelli, Antonio E.; Simao, Cristina A.; Paiva, Maria D.M. [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil); Melo, Marcus A.F. [PETROBRAS, Rio de Janeiro, RJ (Brazil). Centro de Pesquisas (CENPES)

    2004-07-01

    The class-G Portland cement has been used with success in oil well cementing. The material is usually shipped to the Northeast Brazil, because the only plant that manufactures class-G is located in Cantagalo/RJ. The present work investigates the influence of the partial substitution of Portland cement by diatomaceous earth, aiming at reducing the costs in oil well cementing, improving the slurry properties and using local raw material. The diatomaceous earth has pozzolanic properties and can be used as extenders of cement slurries. This properties added to the lower cost and availability of this material in Northeast Brazil, make the diatomaceous earth a candidate material to produce light cements, to well conditions in advanced phases of production. It were evaluated the rheological properties of the slurries (at 25 and 52 deg C), volume of free water, compressive strength after curing for 8, 24 and 48 h at 38 deg C, and consistometry tests. The results show that the diatomaceous earth maintain the viscosity values and gel force suitable for use in oil well cementing. No free water was observed in the formulations. It was also verified that the compressive strength of slurries hardened with diatomaceous earth is similar to those with only Portland cement and that the minimum compressive strength of 300 psi, after curing for 8 h was reached. The thickening time was longer than the average value and the application value. (author)

  8. Tendencias francesas en materia de dolo

    Directory of Open Access Journals (Sweden)

    Aude Denizot-Libreros

    2014-07-01

    Full Text Available Numerosos fallos recientes de la Corte de Casación francesa en materia de dolo han suscitado nuevas investigaciones en la materia. El dolo siempre ha sido una noción ambigua, objeto de un sinnúmero de discusiones. El propósito que se persigue consiste en ofrecer un panorama muy general de las tendencias francesas en esta materia. Estudiar estas tendencias, doctrinales y jurisprudenciales, implica confrontarse con varios temas espinosos, especialmente los de la reticencia, el dolo incidente y el dolo por parte del tercero. También se analiza el dolo con relación a otros conceptos: el error sobre el valor, el error inexcusable, y, en materia de sanción, tanto la pérdida de oportunidad como la noción de refacción del contrato. Entre debates doctrinales y vacilaciones jurisprudenciales, en este tema el derecho francés se caracteriza más por sus aproximaciones que por su rigor, delineando por contraste los impases a evitar.

  9. Tendencias francesas en materia de dolo

    Directory of Open Access Journals (Sweden)

    Aude Denizot-Libreros

    2014-06-01

    Full Text Available Numerosos fallos recientes de la Corte de Casación francesa en materia de dolo han suscitado nuevas investigaciones en la materia. El dolo siempre ha sido una noción ambigua, objeto de un sinnúmero de discusiones. El propósito que se persigue consiste en ofrecer un panorama muy general de las tendencias francesas en esta materia. Estudiar estas tendencias, doctrinales y jurisprudenciales, implica confrontarse con varios temas espinosos, especialmente los de la reticencia, el dolo incidente y el dolo por parte del tercero. También se analiza el dolo con relación a otros conceptos: el error sobre el valor, el error inexcusable, y, en materia de sanción, tanto la pérdida de oportunidad como la noción de refacción del contrato. Entre debates doctrinales y vacilaciones jurisprudenciales, en este tema el derecho francés se caracteriza más por sus aproximaciones que por su rigor, delineando por contraste los impases a evitar.

  10. Understanding cement mechanical behavior in SAGD wells

    Energy Technology Data Exchange (ETDEWEB)

    Xie, J.; Zahacy, T. A. [C-FER Technologies (Canada)

    2011-07-01

    In the heavy oil industry, the steam assisted gravity drainage process is often used to enhance oil recovery but it can cause cracks in the cement sheath. These cracks are the result of high steam temperatures and thermal expansion. In order to mitigate this risk, improved well designs are required. The aim of this paper is to present the mechanical behavior of the cement sheath during the heating phase. An analysis of the impact of design and operating parameters was conducted through thermal hydraulic and thermal mechanical analyses to assess cement integrity. These analyses were then performed on an example of an SAGD project in the southern part of the Athabasca oilsands region to assess the performance of the cement sheath. Results showed that potential damage to the cement can be reduced by slow heating and a lower Young's modulus cement blend. This paper makes recommendations for optimizing cement design in thermal recovery wells.

  11. 2020年我国水泥行业CO2排放趋势与减排路径分析%Analysis on CO2 Emission Trend and Emission Reduction Path of China's Cement Industry in 2020

    Institute of Scientific and Technical Information of China (English)

    蒋小谦; 康艳兵; 刘强; 赵盟

    2012-01-01

    我国水泥行业的CO2排放仅次于电力行业,约占全国排放总量的15%.分析水泥行业的CO2排放趋势和减排路径对实现我国温室气体排放控制目标有着重要的现实意义.本文从影响水泥行业排放的主要影响因素着手,分析了水泥产量和单耗的现状及未来发展趋势,计算了水泥行业的历史排放、发展趋势以及减排潜力,指出了实现减排潜力面临的挑战和障碍,以及相应的措施建议.%CO2 emission from China's cement industry is only second to power industry, accounted for 15% of total national emissions. Analysis on CO2 emission trend and emission reduction path of cement industry is significant to the realization of GHG emissions control target in China. From the perspective of major influencing factors, this paper analyzes the status and future trend of cement production and energy consumption per unit of product, calculates history and future emissions as well as emission reduction potentials, also analyzes challenges and obstacles, and proposes appropriate measures recommendations.

  12. Analysis on Impacts and Co-Abatement Effects of Implementing the Low Carb on Cement Standard

    Institute of Scientific and Technical Information of China (English)

    PANG Jun; SHI Yuan-Chang; FENG Xiang-Zhao; WU Shi-Yu; SUN Wen-Long

    2014-01-01

    Based on the MAP-CGE model, this paper simulated the impacts on the output, energy consumption and pollutant emissions of different cement production processes when implementing a low carbon cement standard in China. It also calculated the impacts on the marginal abatement cost and equilibrium price of the cement industry, and analyzed the co-abatement effects of different pollutants. The results showed that implementing the low carbon cement standard will be beneficial in promoting an upgrading of cement production processes, and strengthening the energy conservation and emission reduction in the cement industry. If there is no change in the existing technology, the cement industry will reduce SO2 emissions by 1.17 kg and NOx emissions by 4.44 kg per ton of CO2 emission reduction. Implementing low carbon cement standard can also promote NOx abatement in the cement industry. However, the cement industry will bear the abatement costs, and their equilibrium price will increase slightly.

  13. The Effects of the Asian Crisis To Turkish Manufacturing Industry : The Case of Textile, Food and Cement Industries = Asya Krizinin Türk İmalat Sanayisine Etkileri: Tekstil, Gıda ve Çimento Sanayileri Örneği

    Directory of Open Access Journals (Sweden)

    Abdülmecit KARATAŞ

    2001-06-01

    Full Text Available This paper hypothesizes that Asian crisis has severely affected the financial dimensions of the Turkish industries. The analysis of the financial data for 70 companies from textile, food and cement industries provides evidence to partially support this hypothesis. By principal components analysis we identified five statistical factors that is meaningful and economically significant to represent main financial dimensions contained in twenty-one financial variables of the sample firms. The discriminant analyses based on the identification of the discrimination between financial dimensions of the sample firms for pre- and post-crisis years identified that profitability margins of the export-oriented Turkish textile industry significantly decreased in post-crisis years. No statistically significant changes in financial dimensions are detected for food and cement industries in post-crisis years.

  14. Bottom-up Representation of Industrial Energy Efficiency Technologies in Integrated Assessment Models for the Cement Sector

    Energy Technology Data Exchange (ETDEWEB)

    Sathaye, J.; Xu, T.; Galitsky, C.

    2010-08-15

    Adoption of efficient end-use technologies is one of the key measures for reducing greenhouse gas (GHG) emissions. How to effectively analyze and manage the costs associated with GHG reductions becomes extremely important for the industry and policy makers around the world. Energy-climate (EC) models are often used for analyzing the costs of reducing GHG emissions for various emission-reduction measures, because an accurate estimation of these costs is critical for identifying and choosing optimal emission reduction measures, and for developing related policy options to accelerate market adoption and technology implementation. However, accuracies of assessing of GHG-emission reduction costs by taking into account the adoption of energy efficiency technologies will depend on how well these end-use technologies are represented in integrated assessment models (IAM) and other energy-climate models.

  15. Diez mega tendencias que revolucionarán la logística de La cadena de abastecimiento

    OpenAIRE

    Bowersox, Donald J.; Closs,David J.; Theodore P. Stank

    2000-01-01

    Las 10 mega-tendencias reflejan los cambios de paradigma fundamentales exhibidos por las principales firmas, al transformar las capacidades de la cadena de abastecimiento para adecuar la transición a largo plazo de una sociedad industrial a una sociedad controlada por la información y la tecnología. Estas mega-tendencias implican un cambio sustancial en la práctica de la logística entre los miembros de la cadena de abastecimiento, al esforzarse por establecer soluciones eficientes, efectivas ...

  16. CO2 Capture for Cement Technology

    DEFF Research Database (Denmark)

    Pathi, Sharat Kumar

    Production of cement is an energy intensive process and is the source of considerable CO2emissions. Itis estimated that the cement industry contributes around 8% of total global CO2emissions. CO2is oneof the major greenhouse gases. In the atmosphere, the CO2concentration has increased from 310...... performed recently has focused on CO2capture from fossil fuel-based power plants. Inherently,this process is especially suitablefor cement plants, as CaO used for CO2capture is also a majoringredient for clinker production. Thus, a detailed investigation was carried outto study the applicationof...... the carbonate looping process to the cement industry. In order to study the application of thecarbonate looping process to cement industry, the project work is divided into three scales: 1) atparticle scale (TGA), 2) at reactor scale (Fluid-bed) and 3) at process scale (process modeling Pro/II).The results from...

  17. Alternative Fuels in Cement Production

    DEFF Research Database (Denmark)

    Larsen, Morten Boberg

    for the most significant alternative fuel energy contributors in the German cement industry. Solid alternative fuels are typically high in volatile content and they may differ significantly in physical and chemical properties compared to traditional solid fossil fuels. From the process point of view......The substitution of alternative for fossil fuels in cement production has increased significantly in the last decade. Of these new alternative fuels, solid state fuels presently account for the largest part, and in particular, meat and bone meal, plastics and tyre derived fuels (TDF) accounted......, considering a modern kiln system for cement production, the use of alternative fuels mainly influences 1) kiln process stability (may accelerate build up of blockages preventing gas and/or solids flow), 2) cement clinker quality, 3) emissions, and 4) decreased production capacity. Kiln process stability...

  18. Physical, chemical and radioactive characterization of co-products from titanium dioxide industry for valorization in the cement industry; Caracterizacion fisico-quimica y radiactiva de los sub-productos provenientes de la industria de dioxido de titanio para su valorizacion en la industria del cemento: implicaciones radiologicas.

    Energy Technology Data Exchange (ETDEWEB)

    Gazquez, M.J.; Mantero, J.; Bolivar, J.P.; Garcia-Tenorio, R.; Vaca, F.

    2011-07-01

    The present study was conducted to characterize the raw materials (ilmenite and slag), waste (red gypsum) and several co-products (sulphate monohydrate and sulphate heptahydrated) form the titanium dioxide industry in relation to their elemental composition (major, minor and trace elements), granulometry, mineralogy, microscopic morphology, physical composition and radioactive content in order to apply this knowledge in the valorization of the co-products in the fields such a as construction, civil engineering, etc. In particular, the main properties of cements produced with different proportions of red gypsum were studied, and the obtained improvements, in relation to Ordinary Portland Cements (OPC) were evaluated. It was also demonstrated that the levels of pollutants and the radioactive content in the produced RG cements, remain within the regulated safety limits. (Author). 38 refs.

  19. Physical, chemical and radioactive characterization of co-products from titanum dioxide industry for valorization in the cement industry; Caracterizacion fisico-quimica y radiactiva de los sub-productos provenientes de la industria de dioxido de titanio para su valorizacion en la industria del cemento: implicaciones radiologicas.

    Energy Technology Data Exchange (ETDEWEB)

    Gazquez, M.J.; Mantero, J.; Bolivar, J.P.; Garcia-Tenorio, R.; Vaca, F.

    2011-07-01

    The present study was conducted to characterize the raw materials (ilmenite and slag), waste (red gypsum) and several co-products (sulphate monohydrate and sulphate heptahydrated) form the titanum dioxide industry in relation to their elemental composition (major, minor and trace elements), granulometry, mineralogy, microscopic morphology, physical composition and radioactive content in order to apply this knowledge in the valorization of the co-products in the fields sucha as construction, civil engineering, etc. In particular, the main properties of cements produced with different proportions of red gypsum were studied, and the obtained improvements, in relation to Ordinary Portland Cements (OPC) were evaluated. It was also demonstrated that the levels of pollutants and the radioactive content in the produced RG cements, remain within the regulated safety limits. (Author). 38 refs.

  20. Carbonate Looping for De-Carbonization of Cement Plants

    OpenAIRE

    2011-01-01

    Cement industry is one of the largest emitter of CO2 other than power generation plants, which includes the emissions from combustion of fuel and also from calcination of limestone for clinker production. In order to reduce CO2 emissions from the cement industry an effective an economically feasible technology is to be developed. The carbonate looping process is a promising technology, which is particularly suitable for the cement industry as limestone could be used for capture and release of...

  1. CEMENT SLURRIES FOR GEOTHERMAL WELLS CEMENTING

    Directory of Open Access Journals (Sweden)

    Nediljka Gaurina-Međimurec

    1994-12-01

    Full Text Available During a well cementing special place belongs to the cement slurry design. To ensure the best quality of cementing, a thorough understanding of well parameters is essential, as well as behaviour of cement slurry (especially at high temperatures and application of proven cementing techniques. Many cement jobs fail because of bad job planning. Well cementing without regarding what should be accomplished, can lead to well problems (channels in the cement, unwanted water, gas or fluid production, pipe corrosion and expensive well repairs. Cementing temperature conditions are important because bot-tomhole circulating temperatures affect slurry thickening time, arheology, set time and compressive strength development. Knowing the actual temperature which cement encounters during placement allows the selection of proper cementing materials for a specific application. Slurry design is affected by well depth, bottom hole circulating temperature and static temperature, type or drilling fluid, slurry density, pumping time, quality of mix water, fluid loss control, flow regime, settling and free water, quality of cement, dry or liquid additives, strength development, and quality of the lab cement testing and equipment. Most Portland cements and Class J cement have shown suitable performances in geot-hermal wells. Cement system designs for geothermal wells differ from those for conventional high temperature oil and gas wells in the exclusive use of silica flour instead of silica sand, and the avoidance of fly ash as an extender. In this paper, Portland cement behaviour at high temperatures is described. Cement slurry and set cement properties are also described. Published in literature, the composition of cement slurries which were tested in geothermal conditions and which obtained required compressive strength and water permeability are listed. As a case of our practice geothermal wells Velika Ciglena-1 and Velika Ciglena-la are described.

  2. Substantial global carbon uptake by cement carbonation

    Science.gov (United States)

    Xi, Fengming; Davis, Steven J.; Ciais, Philippe; Crawford-Brown, Douglas; Guan, Dabo; Pade, Claus; Shi, Tiemao; Syddall, Mark; Lv, Jie; Ji, Lanzhu; Bing, Longfei; Wang, Jiaoyue; Wei, Wei; Yang, Keun-Hyeok; Lagerblad, Björn; Galan, Isabel; Andrade, Carmen; Zhang, Ying; Liu, Zhu

    2016-12-01

    Calcination of carbonate rocks during the manufacture of cement produced 5% of global CO2 emissions from all industrial process and fossil-fuel combustion in 2013. Considerable attention has been paid to quantifying these industrial process emissions from cement production, but the natural reversal of the process--carbonation--has received little attention in carbon cycle studies. Here, we use new and existing data on cement materials during cement service life, demolition, and secondary use of concrete waste to estimate regional and global CO2 uptake between 1930 and 2013 using an analytical model describing carbonation chemistry. We find that carbonation of cement materials over their life cycle represents a large and growing net sink of CO2, increasing from 0.10 GtC yr-1 in 1998 to 0.25 GtC yr-1 in 2013. In total, we estimate that a cumulative amount of 4.5 GtC has been sequestered in carbonating cement materials from 1930 to 2013, offsetting 43% of the CO2 emissions from production of cement over the same period, not including emissions associated with fossil use during cement production. We conclude that carbonation of cement products represents a substantial carbon sink that is not currently considered in emissions inventories.

  3. Stabilization effects of surplus soft clay with cement and GBF slag

    Institute of Scientific and Technical Information of China (English)

    LU Jiang; Chirdchanin MODMOLTIN; Katsutada ONITSUKA

    2004-01-01

    Utilization of industrial waste and surplus construction soft clay as construction material was recommended, and many attempts at geotechnical waste utilization were undertaken. This study aimed at the application of cement and a kind of industrial wastes, i.e. granulated blast furnace slag, on stabilization of surplus soft clay. The results showed that the cement and slag can successfully stabilize Ariake clays even though this high organic clay fails to be stabilized by lime and cement. Addition of slag in cement for stabilization induces higher strength than cement alone for longer curing time. The application of the cement with slag is more suitable than cement alone for stabilization because of economical consideration.

  4. Lunar cement

    Science.gov (United States)

    Agosto, William N.

    1992-01-01

    With the exception of water, the major oxide constituents of terrestrial cements are present at all nine lunar sites from which samples have been returned. However, with the exception of relatively rare cristobalite, the lunar oxides are not present as individual phases but are combined in silicates and in mixed oxides. Lime (CaO) is most abundant on the Moon in the plagioclase (CaAl2Si2O8) of highland anorthosites. It may be possible to enrich the lime content of anorthite to levels like those of Portland cement by pyrolyzing it with lunar-derived phosphate. The phosphate consumed in such a reaction can be regenerated by reacting the phosphorus product with lunar augite pyroxenes at elevated temperatures. Other possible sources of lunar phosphate and other oxides are discussed.

  5. in the Portland cement industry

    Directory of Open Access Journals (Sweden)

    José Pablo Paredes-Sánchez

    2015-01-01

    Full Text Available Este artículo describe una herra mienta de simulación bajo el en torno de Matlab®, que puede ser utilizada para estimar la auton omía de un vehículo con baterías o híbrido con pila de combustible y bater ías. El modelo es función de variables mecánicas y físicas que dependerán no solo del propio vehículo sino también del terreno. Su uso es extendido para recorridos obtenidos mediante dispositivos GPS y para ciclos estándar. Pueden obtenerse diferentes variables de salid a tales como: el consumo de hidrógeno y batería, el nivel hidró geno, el estado de carga de la batería, la potencia consumida, la producción de energía por parte de la pila, el máximo alcance del vehículo y el máximo número de ciclos finalizados. La simulación de rutas reales pro porciona una buena aproximación de la velocidad del vehículo pa ra usos, en lugar de utilizar ciclos de c onducción estándar, obteniendo así aproximaciones bas tante arbitrarias para una ruta real.

  6. Globally Oriented Chinese Plastics Industry

    Institute of Scientific and Technical Information of China (English)

    Liao Zhengpin

    2004-01-01

    @@ Through continued endeavor and persistent opening to the whole world the Chinese plastics industry has been developed into a comprehensive industrial system that forms the basic material industries side by side with the steel, cement and the timber industry.

  7. Analysis of Waste Gas Volume and Pollutants Reduction Potential for Cement Industry in China%我国水泥工业废气量减排与污染物减排潜力分析

    Institute of Scientific and Technical Information of China (English)

    王红梅; 刘宇; 王凡; 都基峻; 张凡; 石应杰

    2015-01-01

    水泥工业是颗粒物等大气污染物排放量较大的行业,因排放标准中颗粒物等污染物浓度限值已非常严格,依靠加严标准减排污染物的空间已经越来越小,标准减排难以使水泥工业实现更高的减排目标。水泥生产多个工序会排放废气,在排放标准限值不变的条件下,各类废气的排放总量决定了颗粒物等污染物的排放总量。通过实例分析得出利用窑头余风再循环、减少窑头喂煤一次风比例和分解炉喂煤风机的风量可实现高温废气量的减排,利用窑头窑尾低温废热进行烘干物料可实现低温烘干废气量的减排,将常温废气作为水泥窑窑头和分解炉煤粉的助燃空气可实现常温废气量的减排,进一步分析了通过废气量减排可实现颗粒物等污染物的减排量。%Cement industry yields a large air pollution emission including particulate matters.As the particulate concentration limits in the industrial emission standard has been very strict, it leaves smaller and smaller space to further reduce the pollutant emission by setting stricter standard limits.Therefore, the emission reduction by standard has been difficult to make cement industry to achieve a higher reduction target.There are several processes in cement production that emit waste gases.Under the same emission standard limits, the total emissions of various pollutants will be determined by the total waste gas volumes of various kinds.Through case studies, it was shown that the kiln end afterwinds could be recycled to reduce the primary air ratio in kiln end coal feeding and the coal-feeding fan air volume in calcining combustors, so as to realize reduction of high-temperature waste gas volume. The cement kiln end low-temperature waste heat could be used to dry materials and thus realize reduction of waste gas volume in low-temperature drying.The room-temperature exhaust gas could be used as pulverized coal combustion air

  8. El diseño del parque urbano: orígenes y tendencias

    OpenAIRE

    1992-01-01

    En el siglo XIX se consolida en Europa la tendencia a incorporar parques públicos en las grandes ciudades. Aparece de este modo el parque urbano en la historia de la ciudad como un equipamiento nuevo destinado a dar respuesta a los acuciantes problemas originados con la revolución industrial. También en la historia de la jardinería el surgimiento de este espacio verde público significó un desafío para las llamadas artes del jardín que hasta entonces habían respondido sólo a la clase...

  9. ULTRA-LIGHTWEIGHT CEMENT

    Energy Technology Data Exchange (ETDEWEB)

    Fred Sabins

    2002-07-30

    The objective of this project is to develop an improved ultra-lightweight cement using ultra-lightweight hollow glass spheres (ULHS). This report includes results from laboratory testing of ULHS systems along with other lightweight cement systems, including foamed and sodium silicate slurries. During this project quarter, a comparison study of the three cement systems examined the effect that cement drillout has on the three cement systems. Testing to determine the effect of pressure cycling on the shear bond properties of the cement systems was also conducted. This report discusses testing that was performed to analyze the alkali-silica reactivity of ULHS in cement slurries.

  10. Characteristics of Carbon Dioxide Emission from China's Cement Industry and Its Dynamic Development%我国水泥工业碳排放特征及动态变化分析

    Institute of Scientific and Technical Information of China (English)

    李新; 吕淑珍; 王海滨; 石建屏

    2013-01-01

    水泥工业是温室气体二氧化碳(CO2)的主要排放源,利用碳排放数学模型计算2001-2010年我国水泥工业碳的排放量,分析碳排放量的变化特点和发展趋势.结果表明:水泥工业碳排放总量逐年增长,与水泥产量和排放强度呈线性关系.“十一五”期间单位产品碳排放强度由0.69t/t下降到0.65t/t.万元GDP碳排放量2008年达到最低值为0.295 1 t,平均每年万元GDP碳排放量下降2.85%.水泥工业十年间实施节能降耗、资源循环利用、提高经济效益等措施,对于减少碳排放具有明显效果.%Cement industry is a major source of greenhouse gas- carbon dioxide (CO2) emission. Mathematical model was used to calculate carbon emission quantities for China's cement industry during 2001 to 2010, and change characteristics and trend for carbon emission with cement outputs and emission factors were analyzed. Results indicated that carbon emissions quantities increased rapidly every year, and there is a linear relationship between carbon emission quantities and cement output, emission factors. Carbon emission factors decreased from 0.69 t/t to 0.65 t/t during the 11 th Five- Year- Plan period. Carbon emission quantities of ten thousand Yuan GDP decreased to minimum 0.295 1 t in 2008, decreased by 2.85%. Results showed that the energy saving and resource recycling and increase of economic efficiency are appearing in the reduction of carbon emissions.

  11. 利用水泥固化废弃物减少有害金属离子溶出的试验探索%Use of cement curing a variety of industrial waste reduction of underground water pollution

    Institute of Scientific and Technical Information of China (English)

    何军志; 赵国燕

    2012-01-01

    水泥和混凝土行业对工业废弃物以及生活废弃物的利用虽然减少了环境负荷,在水泥水化过程中废弃物中存在的有害金属离子受到一定程度的固结,但在某种条件下还会有所溶出而重新释放到大自然,造成对环境的二次污染,需要探寻能够模拟真实状况的浸出试验对混凝土材料中有害金属离子的浸出进行测试,来考察水泥混凝土材料与炉渣以及垃圾焚烧灰、电镀污泥、城市污水河底泥、建筑垃圾、建材废料、电池废渣、污水处理厂污泥等配制成的复合废弃物对有害金属离子的固化程度,进而考察水泥混凝土材料在利用废弃物的同时对环境保护所起的作用,这对水泥工业利用各种废物降低成本、固结有害成分的实验方法、组合配方、掺料路径的筛选有着重要的指导意义.%For the cement and concrete industry, although a lot of applications of industrial waste and domestic waste can reduce environmental load of cement hydration process in the presence of waste in the heavy metal ions and other harmful metals to a certain extent, under certain conditions it can also be stripping back the release to the nature to cause secondary pollution to the environment. This paper can simulate the real situation of the leaching tests on concrete materials and harmful heavy metals in the leaching of metal ions which were measured to evaluate the use of cement and concrete materials fly ash, slag, waste incineration ash, sludge, sewage river sediment, construction waste, building materials waste, battery waste, sewage sludge and other waste during the performance in ensuring the use of materials under the premise on one of the heavy metals and harmful metal ions curing degree, then study the use of cement and concrete waste, and the role of environmental protection.

  12. Gaps between China and developed countries for disposal of social wastes in cement industry%中国水泥工业消纳社会废弃物与发达国家的差距

    Institute of Scientific and Technical Information of China (English)

    高长明

    2009-01-01

    PC kiln systems can digest various wastes which contain combustible matters.It can not only make full use of their surplus calorie,but also can absolutely dispose their residuals after combustion to eliminate thepossibility of secondary contamination.Because of the extensive adaptability of cement kiln,which can dispose various wastes in great quantity,it is more economical,convenient and effective to use cement kiln than to build new waste land-filling deposits or new incinerators for waste disposal.Also,cement industry can utilize various industrial slags as admixture to be blended into clinker for cement grinding;and even some of the industrial wastes can be used as substitutiOns of natural raw materials like limestone,clay or pyrites etc.Gaps still exist between China and developed countries like Germany,Japan and U.S.In both ideology and technology for disposal of social wastes in cement industry.In China, although admixtures are widely used to outward seeming,but inded,this is resulted by over-intermingled or indiscriminately-intermingled.There are still big rooms for raising the substitution rate for raw materials and gypsum in China,and also,application of alternative fuels is in backward position,with which we must rouse ourselves to catch up.%预分解水泥窑消纳各种含有可燃质的废物,既可充分利用其残留的热值,还能彻底干净地处置其燃烧后的残渣,消除二次污染隐患;加之水泥窑适应范围广,可以消纳各种状态的废料,处置能力很大.此法比新建垃圾填埋场或焚烧厂等办法经济得多,收效更快.水泥工业还可以将各种工业废渣用作混合材掺于水泥熟料中一并粉磨成水泥;有的工业废料还可以用作水泥原料以替代天然的石灰石、粘土或铁矿石等.在水泥工业消纳社会废弃物方面,我国与德日美等发达国家,在理念和技术上还有差距:我国看似消纳混合材不少,实为部分超掺滥掺所致;我国原料和石膏的

  13. Low pH Cements

    Energy Technology Data Exchange (ETDEWEB)

    Savage, David; Benbow, Steven [Quintessa Ltd., Henley-on-Thames (United Kingdom)

    2007-05-15

    The development of low-pH cements for use in geological repositories for radioactive waste stems from concerns over the potential for deleterious effects upon the host rock and other EBS materials (notably bentonite) under the hyperalkaline conditions (pH > 12) of cement pore fluids. Low pH cement (also known as low heat cement) was developed by the cement industry for use where large masses of cement (e.g. dams) could cause problems regarding heat generated during curing. In low pH cements, the amount of cement is reduced by substitution of materials such as fly ash, blast furnace slag, silica fume, and/or non-pozzolanic silica flour. SKB and Posiva have ruled out the use of blast furnace slag and fly-ash and are focusing on silica fume as a blending agent. Currently, no preferred composition has been identified by these agencies. SKB and Posiva have defined a pH limit {<=} 11 for cement grout leachates. To attain this pH, blending agents must comprise at least 50 wt % of dry materials. Because low pH cement has little, or no free portlandite, the cement consists predominantly of calcium silicate hydrate (CSH) gel with a Ca/Si ratio {<=} 0.8. Although there are potential implications for the performance of the spent fuel and cladding due to the presence of hyperalkaline fluids from cement, the principal focus for safety assessment lies with the behaviour of bentonite. There are a number of potential constraints on the interaction of hyperalkaline cement pore fluids with bentonite, including mass balance, thermodynamic issues, mass transport, and kinetics, but none of these is likely to be limiting if conventional OPC cements are employed in repository construction. Nevertheless: Low-pH cements may supply approximately 50 % less hydroxyl ions than conventional OPC for a given volume of cement, but mass balance constraints are complicated by the uncertainty concerning the type of secondary minerals produced during cement-bentonite interaction. The change of aqueous

  14. Low pH Cements

    Energy Technology Data Exchange (ETDEWEB)

    Savage, David; Benbow, Steven [Quintessa Ltd., Henley-on-Thames (United Kingdom)

    2007-05-15

    The development of low-pH cements for use in geological repositories for radioactive waste stems from concerns over the potential for deleterious effects upon the host rock and other EBS materials (notably bentonite) under the hyperalkaline conditions (pH > 12) of cement pore fluids. Low pH cement (also known as low heat cement) was developed by the cement industry for use where large masses of cement (e.g. dams) could cause problems regarding heat generated during curing. In low pH cements, the amount of cement is reduced by substitution of materials such as fly ash, blast furnace slag, silica fume, and/or non-pozzolanic silica flour. SKB and Posiva have ruled out the use of blast furnace slag and fly-ash and are focusing on silica fume as a blending agent. Currently, no preferred composition has been identified by these agencies. SKB and Posiva have defined a pH limit {<=} 11 for cement grout leachates. To attain this pH, blending agents must comprise at least 50 wt % of dry materials. Because low pH cement has little, or no free portlandite, the cement consists predominantly of calcium silicate hydrate (CSH) gel with a Ca/Si ratio {<=} 0.8. Although there are potential implications for the performance of the spent fuel and cladding due to the presence of hyperalkaline fluids from cement, the principal focus for safety assessment lies with the behaviour of bentonite. There are a number of potential constraints on the interaction of hyperalkaline cement pore fluids with bentonite, including mass balance, thermodynamic issues, mass transport, and kinetics, but none of these is likely to be limiting if conventional OPC cements are employed in repository construction. Nevertheless: Low-pH cements may supply approximately 50 % less hydroxyl ions than conventional OPC for a given volume of cement, but mass balance constraints are complicated by the uncertainty concerning the type of secondary minerals produced during cement-bentonite interaction. The change of aqueous

  15. Contact dermatitis in cement workers in Isfahan

    Directory of Open Access Journals (Sweden)

    Iraji Fariba

    2006-01-01

    Full Text Available BACKGROUND: Due to recent industrialization and inadequately protected workers or in other words poor supervision on constructive workers habits in our large city of Isfahan cement contact dermatitis is relatively high especially among cement factory workers and constructive personnel. PURPOSES: To investigate the prevalence rate of cement contact dermatitis in cement factory workers in Isfahan. METHODS: A case-control clinical study was carried out by randomly selecing 150 factory workders and 150 official clerks in a cement factory in Isfahan in 2001. After a complete physical examination, data was recorded in observational checklists. FINDINGS: The percentages of contact dermatitis prevalences in the first and the second groups were 22% and 5.3% respectively. About 60% of cement workers with contact dermatitis were between 30-40 years of age. There was a direct relationship with age in both groups of the workers. In the high-exposure group, the hand eczema along was 70% but in the other group the percentage of involvement was the same in exposed and unexposed anatomical areas. CONCLUSIONS: There was a direct relationship between occurrence and the severity of involvement and duration of contact in the first group. Cent percent of cement workers had contact dermatitis after 10 or less years, but the percentage among the other group was 35%. LIMITATION: Irritant contact dermatitis to cement has not been detected.

  16. ADVANCED CEMENTS FOR GEOTHERMAL WELLS

    Energy Technology Data Exchange (ETDEWEB)

    SUGAMA,T.

    2007-01-01

    Using the conventional well cements consisting of the calcium silicate hydrates (CaO-SiO{sub 2}-H{sub 2}O system) and calcium aluminum silicate hydrates (CaO-Al{sub 2}O{sub 3}-SiO{sub 2}-H{sub 2}O system) for the integrity of geothermal wells, the serious concern confronting the cementing industries was their poor performance in mechanically supporting the metallic well casing pipes and in mitigating the pipe's corrosion in very harsh geothermal reservoirs. These difficulties are particularly acute in two geological regions: One is the deep hot downhole area ({approx} 1700 m depth at temperatures of {approx} 320 C) that contains hyper saline water with high concentrations of CO{sub 2} (> 40,000 ppm) in conjunction with {approx} 100 ppm H{sub 2}S at a mild acid of pH {approx} 5.0; the other is the upper well region between the well's surface and {approx} 1000 m depth at temperatures up to 200 C. The specific environment of the latter region is characterized by highly concentrated H{sub 2}SO{sub 4} (pH < 1.5) brine containing at least 5000 ppm CO{sub 2}. When these conventional cements are emplaced in these harsh environments, their major shortcoming is their susceptibility to reactions with hot CO{sub 2} and H{sub 2}SO4, thereby causing their deterioration brought about by CO{sub 2}-catalyzed carbonation and acid-initiated erosion. Such degradation not only reduced rapidly the strength of cements, lowering the mechanical support of casing pipes, but also increased the extent of permeability of the brine through the cement layer, promoting the rate of the pipe's corrosion. Severely carbonated and acid eroded cements often impaired the integrity of a well in less than one year; in the worst cases, casings have collapsed within three months, leading to the need for costly and time-consuming repairs or redrilling operations. These were the reasons why the geothermal well drilling and cementing industries were concerned about using conventional well

  17. Tendencias en infraestructuras de datos espaciales en el contexto latinoamericano

    OpenAIRE

    2014-01-01

    Las infraestructuras de datos espaciales (IDE), a causa del cambio propiciado por tendencias tecnológicas como son dispositivos móviles, sensores y web2.0, están convergiendo hacia sistemas móviles, en tiempo real y con participación activa de los ciudadanos. Si bien estas tendencias ya han sido analizadas e integradas como parte de las IDE en Europa y Norteamérica, en el contexto Latinoamericano no se han investigado ni desarrollado lo suficiente. Por ello, con el objetivo de contribuir con ...

  18. The suitability of a supersulfated cement for nuclear waste immobilisation

    Science.gov (United States)

    Collier, N. C.; Milestone, N. B.; Gordon, L. E.; Ko, S.-C.

    2014-09-01

    Composite cements based on ordinary Portland cement are used in the UK as immobilisation matrices for low and intermediate level nuclear wastes. However, the high pore solution pH causes corrosion of some metallic wastes and undesirable expansive reactions, which has led to alternative cementing systems being examined. We have investigated the physical, chemical and microstructural properties of a supersulfated cement in order to determine its applicability for use in nuclear waste encapsulation. The hardened supersulfated cement paste appeared to have properties desirable for use in producing encapsulation matrices, but the high powder specific surface resulted in a matrix with high porosity. Ettringite and calcium silicate hydrate were the main phases formed in the hardened cement paste and anhydrite was present in excess. The maximum rate of heat output during hydration of the supersulfated cement paste was slightly higher than that of a 9:1 blastfurnace slag:ordinary Portland cement paste commonly used by the UK nuclear waste processing industry, although the total heat output of the supersulfated cement paste was lower. The pH was also significantly lower in the supersulfated cement paste. Aluminium hydroxide was formed on the surface of aluminium metal encapsulated in the cement paste and ettringite was detected between the aluminium hydroxide and the hardened cement paste.

  19. International Best Practices for Pre-Processing and Co-Processing Municipal Solid Waste and Sewage Sludge in the Cement Industry

    Energy Technology Data Exchange (ETDEWEB)

    Hasanbeigi, Ali [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Lu, Hongyou [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Williams, Christopher [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Price, Lynn [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2012-07-01

    The purpose of this report is to describe international best practices for pre-processing and coprocessing of MSW and sewage sludge in cement plants, for the benefit of countries that wish to develop co-processing capacity. The report is divided into three main sections. Section 2 describes the fundamentals of co-processing, Section 3 describes exemplary international regulatory and institutional frameworks for co-processing, and Section 4 describes international best practices related to the technological aspects of co-processing.

  20. Tendencias Actuales de la Integración Economica

    OpenAIRE

    López Zamarripa, Norka

    2011-01-01

    SUMARIO: I. Introducción. II. Precisiones conceptuales. III. Tendencias actuales de la integración económica a nivel internacional. IV. Los costos de la no integración. V. Elementos para el diseño de un modelo de integración autóctono. VI. Consideraciones finales.

  1. Turismo Gastronómico y Nuevas Tendencias

    OpenAIRE

    2014-01-01

    ACTAS del VIII Seminario de Otoño: "TURISMO GASTRONÓMICO Y NUEVAS TENDENCIAS" Organizan: Fundación Ciencias Sociales y Mundo Mediterráneo y la Universidad Rey Juan Carlos Celebrado en Calpe (Alicante) 18 y 19 de Octubre Organizan: Fundación Ciencias Sociales y Mundo Mediterráneo y la Universidad Rey Juan Carlos

  2. The suitability of a supersulfated cement for nuclear waste immobilisation

    Energy Technology Data Exchange (ETDEWEB)

    Collier, N.C., E-mail: nick.collier@sheffield.ac.uk [Immobilisation Science Laboratory, Department of Materials Science and Engineering, The University of Sheffield, Mappin Street, Sheffield S1 3JD (United Kingdom); Milestone, N.B. [Immobilisation Science Laboratory, Department of Materials Science and Engineering, The University of Sheffield, Mappin Street, Sheffield S1 3JD (United Kingdom); Callaghan Innovation, 69 Gracefield Road, PO Box 31310, Lower Hutt 5040 (New Zealand); Gordon, L.E. [Immobilisation Science Laboratory, Department of Materials Science and Engineering, The University of Sheffield, Mappin Street, Sheffield S1 3JD (United Kingdom); Geopolymer and Minerals Processing Group, Department of Chemical and Biomolecular Engineering, University of Melbourne, Parkville, Victoria 3010 (Australia); Ko, S.-C. [Holcim Technology Ltd, Hagenholzstrasse 85, CH-8050 Zurich (Switzerland)

    2014-09-15

    Highlights: • We investigate a supersulfated cement for use as a nuclear waste encapsulant. • High powder fineness requires a high water content to satisfy flow requirements. • Heat generation during hydration is similar to a control cement paste. • Typical hydration products are formed resulting in a high potential for waste ion immobilisation. • Paste pH and aluminium corrosion is less than in a control cement paste. - Abstract: Composite cements based on ordinary Portland cement are used in the UK as immobilisation matrices for low and intermediate level nuclear wastes. However, the high pore solution pH causes corrosion of some metallic wastes and undesirable expansive reactions, which has led to alternative cementing systems being examined. We have investigated the physical, chemical and microstructural properties of a supersulfated cement in order to determine its applicability for use in nuclear waste encapsulation. The hardened supersulfated cement paste appeared to have properties desirable for use in producing encapsulation matrices, but the high powder specific surface resulted in a matrix with high porosity. Ettringite and calcium silicate hydrate were the main phases formed in the hardened cement paste and anhydrite was present in excess. The maximum rate of heat output during hydration of the supersulfated cement paste was slightly higher than that of a 9:1 blastfurnace slag:ordinary Portland cement paste commonly used by the UK nuclear waste processing industry, although the total heat output of the supersulfated cement paste was lower. The pH was also significantly lower in the supersulfated cement paste. Aluminium hydroxide was formed on the surface of aluminium metal encapsulated in the cement paste and ettringite was detected between the aluminium hydroxide and the hardened cement paste.

  3. Asphalt cement poisoning

    Science.gov (United States)

    ... petroleum material that hardens when it cools. Asphalt cement poisoning occurs when someone swallows asphalt. If hot ... found in: Road paving materials Roofing materials Tile cements Asphalt may also be used for other purposes.

  4. Carbonate Looping for De-Carbonization of Cement Plants

    DEFF Research Database (Denmark)

    Pathi, Sharat Kumar; Andersen, Maria Friberg; Lin, Weigang

    2011-01-01

    Cement industry is one of the largest emitter of CO2 other than power generation plants, which includes the emissions from combustion of fuel and also from calcination of limestone for clinker production. In order to reduce CO2 emissions from the cement industry an effective an economically...... feasible technology is to be developed. The carbonate looping process is a promising technology, which is particularly suitable for the cement industry as limestone could be used for capture and release of CO2. Integration of carbonate looping process into cement pyroprocess has two advantages: 1...... integrated into cement pyro-process. The energy required for regeneration in the calciner increases with increase in average conversion of calcined limestone and energy that can be extracted from carbonator decreases with increasing average conversion. Further the influence of type of limestone...

  5. Basalt waste added to Portland cement

    Directory of Open Access Journals (Sweden)

    Thiago Melanda Mendes

    2016-08-01

    Full Text Available Portland cement is widely used as a building material and more than 4.3 billion tons were produced in 2014, with increasing environmental impacts by this industry, mainly through CO2 emissions and consumption of non-removable raw materials. Several by-products have been used as raw materials or fuels to reduce environmental impacts. Basaltic waste collected by filters was employed as a mineral mixture to Portland cement and two fractions were tested. The compression strength of mortars was measured after 7 days and Scanning Electron Microscopy (SEM and Electron Diffraction Scattering (EDS were carried out on Portland cement paste with the basaltic residue. Gains in compression strength were observed for mixtures containing 2.5 wt.% of basaltic residue. Hydration products observed on surface of basaltic particles show the nucleation effect of mineral mixtures. Clinker substitution by mineral mixtures reduces CO2 emission per ton of Portland cement.

  6. Cement dust exposure-related emphysema in a construction worker

    Directory of Open Access Journals (Sweden)

    V Karkhanis

    2011-01-01

    Full Text Available Although, smoking is considered the most important predisposing factor in development of emphysema; environmental exposures also play an important role. There have been several studies on work related respiratory symptoms and ventilatory disorders among employees of cement industry. We report a case of cement exposure related emphysema in 75 years old woman construction worker.

  7. Influence of relationship water/cement upon the processing of cements with pozzolana in standard mortar

    Directory of Open Access Journals (Sweden)

    Gener Rizo, M.

    2002-03-01

    Full Text Available The processing of standard mortar is completed following different methods in accordance with the country, but they exist two fundamental tendecies, the ISO and the ASTM. The cuban norm for mechanic-physic tests is based in ISO, and so they use a constant relationship water/cement in the processing of standard mortar a great problem concerning the cement users when they tested those mixed with puzzolanes, because they don't take care of the bigger water needs of those materials. In this work we present an study of the behaviour of Pozzolanic Portland cements (PP-250 elaborates with a fix and changeable relationship water/cement, obtained starting from the fluidity of the pure Portland cement. (P-350 The results obtained shows that the mechanical resistance decreased in cement mortars PP-250 realised with changeable relationship water/cement. So we recommend the adoption of an optional procedure to elaborate a quality mortar with pozzolana cements.

    La elaboración del mortero normalizado se realiza internacionalmente por diferentes métodos, pero existen dos tendencias fundamentales, la enunciada por ISO y por ASTM. La norma cubana de ensayos físico-mecánicos de cemento se basa en la norma ISO, por lo que para la elaboración del mortero normalizado se utiliza una relación agua/cemento constante. Esto ha provocado discrepancias con los usuarios del cemento, especialmente cuando se ensayan los cementos que contienen puzolanas, ya que se plantea que no se tiene en cuenta la mayor demanda de agua de estos materiales. En el presente trabajo se presenta un estudio del comportamiento de cementos Portland Puzolánicos (PP-250 elaborados con una relación agua/ cemento fija y variable, lograda a partir de la fluidez de la pasta de cemento Portland puro (P-350. Los resultados obtenidos indican que se producen disminuciones en la resistencia mecánica en los morteros de cemento PP-250 elaborados con agua/ cemento variable y recomienda la

  8. 77 FR 42367 - National Emission Standards for Hazardous Air Pollutants for the Portland Cement Manufacturing...

    Science.gov (United States)

    2012-07-18

    ... Standards for Hazardous Air Pollutants for the Portland Cement Manufacturing Industry and Standards of Performance for Portland Cement Plants; Proposed Rule #0;#0;Federal Register / Vol. 77 , No. 138 / Wednesday...-AQ93 National Emission Standards for Hazardous Air Pollutants for the Portland Cement...

  9. Reuse of a residue from petrochemical industry with portland cement Reutilización de un residuo de la industria petroquímica como adición al cemento portland

    Directory of Open Access Journals (Sweden)

    Janneth Torres Agredo

    2012-06-01

    Full Text Available In this article the possibility of using waste from the petrochemical industry,as partial replacement of Portland cement is studied, evaluating the presenceof contaminants in the waste and the encapsulation, once it is confined on the cement. This has been done, in order to find a use to this residue without cause damage to the environment. This residue, called spent fluid catalytic cracking catalyst (FCC, is mainly formed by a type Y zeolite, which is dispersing in an inorganic oxides matrix. The toxicity characteristic leaching proceeding was applied, in mortars adding with 20% of FCC as Portland cement replacement. The results showed that the residue does not represent a problem from the point of view of the leaching of elements, such as As, Pb, Zn, Cr, and La, which were below to the permissible limits. Additionally, the pozzolanic activity of FCC was evaluated according to ASTM C311, where the efficiency of the residue as pozzolanic addition is demonstrated. With the results the importance of reusing a residue of the petrochemical industry is emphasized, that decreases the amount of cement to be used and improves the mechanical resistance of the materials containing it.En el presente artículo se estudia la posibilidad de utilizar un residuo de la industria petroquímica, como sustitución parcial del cemento Portland, evaluando la presencia de elementos contaminantes en el residuo y su encapsulación, una vez se haya confinado con el cemento. Lo anterior, con el fin de determinar si su uso como material de construcción, puede o no causar un efecto negativo al medio ambiente. El residuo, denominado catalizador usado de craqueo catalítico (FCC, es un material que está compuesto por una zeolita tipo Y, dispersa en una matriz de óxidos inorgánicos. Se aplicó la técnica de TCLP (del inglés Toxicity Characteristic Leaching Procedure, en morteros adicionados con un 20%, de FCC con respecto a la cantidad de cemento. Los resultados

  10. 混凝土与水泥制品行业上半年继续领跑建材工业%The First Half of 2011 for Concrete and Cement Products Industry: Go on Leading the Building Materials Industry Growth

    Institute of Scientific and Technical Information of China (English)

    沈冰

    2011-01-01

    今年以来,全社会固定资产投资依然保持较快增长,意味着混凝土与水泥制品行业生产与经济增长的外在动力依然强劲.上半年,混凝土与水泥制品行业经济运行延续了上年平稳较快发展的态势,行业主要产品和经济效益实现平稳较快增长,继续领跑建材工业.The fixed assets investment growth remained fast in the first half of 2011,meaning the driving force of concrete and cement products production and economic growth still strong.The performance of the concrete and cement products industry maintained the momentum of the steady and rapid development in the first half of the year;the output of main products grew steadily as well as the profit making.It continued to lead the growth of the building materials industry.

  11. Alternative Fuels in Cement Production

    OpenAIRE

    2007-01-01

    Substitutionen af fossilt med alternativt brændsel i cement produktionen er steget betydeligt i den sidste dekade. Af disse nye alternative brændsler, udgør de faste brændsler p.t. den største andel, hvor kød- og benmel, plastic og dæk i særdeleshed har været de alternative brændsler der har bidraget med mest alternativ brændsels energi til den tyske cement industri. De nye alternative brændsler er typisk karakteriseret ved et højt indhold af flygtige bestanddele og adskiller sig typisk fra t...

  12. Research of magnesium phosphosilicate cement

    Science.gov (United States)

    Ding, Zhu

    Magnesium phosphosilicate cement (MPSC) is a novel phosphate bonded cement, which consists mainly of magnesia, phosphate and silicate minerals. The traditional magnesium phosphate cements (MPCs) usually composed by ammonium phosphate, and gaseous ammonia will emit during mixing and in service. There is no noxious ammonia released from MPSC, furthermore, it can recycle a large volume of the non-hazardous waste. The goal of this research is to investigate the composition, reaction products, reaction mechanism, microstructure, properties, durability and applications of the MPSC. MPSC sets rapidly and has high early strength. It reacts better with solid industrial waste when compared to Portland cement. Many solid industrial wastes, such as fly ash, steel slag, coal gangue, red coal gangue, red mud, barium-bearing slag, copper slag, silica fume, and ground granulated blast furnace slag, have been used as the main component (40% by weight) in MPSC. The research has found that these aluminosilicate (or ironsilicate, or calciumsilicate) minerals with an amorphous or glass structure can enhance the performance of MPSC. The disorganized internal structure of amorphous materials may make it possess higher reactivity compared to the crystalline phases. Chemical reaction between phosphate and these minerals may form an amorphous gel, which is favorable to the cementing. Borax, boric acid and sodium tripolyphosphate have been used as retardants in the MPSC system. It is found that boric acid has a higher retarding effect on the setting of cement, than borax does. However, sodium polyphosphate accelerates the reaction of MPSC. The hydration of MPSC is exothermic reaction. The heat evolution may prompt hydrates formation, and shorten the setting process. Modern materials characterization techniques, XRD, DSC, TG-DTA FTIR, XPS, MAS-NMR, SEM, TEM, MIP, etc. were used to analyze the phase composition, micro morphology, and microstructure of hardened MPSC. The main hydration product

  13. The Discussion of Capacity “Pseudo-surplus” in Steel and Cement Industry of China%现阶段我国钢铁、水泥行业产能“伪过剩”刍议

    Institute of Scientific and Technical Information of China (English)

    唐兴和

    2014-01-01

    目前,各界普遍认为当前我国钢铁、水泥行业存在严重的产能过剩。笔者认为,这种观点值得商榷。这是因为:以产能利用率为指标评价产能过剩状况,其科学性需要商讨;当前我国钢铁、水泥行业的产能过剩具有阶段性、结构性、区域性和相对性等几个特征;基于我国现存的巨大潜在需求转化为现实需求将有效释放过剩产能的判断,得出我国现阶段的产能过剩是伪过剩。在此基础上,立足发挥宏观调控和市场机制双重作用,从控制新增、消化现存、淘汰落后等几方面提出化解过剩产能的政策建议。%At present, it is generally believed that there is serious overcapacity in China’ s steel and cement industry. In my opinion, this point of view is debatable for the following reasons:first, assessing the situation of overcapacity by the rate of capacity utilization is questionable;second, the current overcapacity of steel and cement industry has periodic, structural, regional and relative features;based on the judgment that China’ s tremendous existing potential demand can be transformed into real demand and therefore effectively release the overcapacity, I can draw the conclusion that the current overcapacity is an illusion. From this analysis, by giving full play to the role of macro-regulation and market mechanism, this article offers some policy recommendations to resolve the problem of overcapacity, including controlling expansion of production capacity, digesting existing capacity and eliminating backward capacity, etc.

  14. An assessment of gas-side fouling in cement plants

    Science.gov (United States)

    Marner, W. J.

    1982-01-01

    The cement industry is the most energy-intensive industry in the United States in terms of energy cost as a percentage of the total product cost. An assessment of gas-side fouling in cement plants with special emphasis on heat recovery applications is provided. In the present context, fouling is defined as the buildup of scale on a heat-transfer surface which retards the transfer of heat and includes the related problems of erosion and corrosion. Exhaust gases in the cement industry which are suitable for heat recovery range in temperature from about 100 to 1300 K, are generally dusty, may be highly abrasive, and are often heavily laden with alkalies, sulfates, and chlorides. Particulates in the exhaust streams range in size from molecular to about 100 micrometers in diameter and come from both the raw feed as well as the ash in the coal which is the primary fuel used in the cement industry. The major types of heat-transfer equipment used in the cement industry include preheaters, gas-to-air heat exchangers, waste heat boilers, and clinker coolers. At the present time, the trend in this country is toward suspension preheater systems, in which the raw feed is heated by direct contact with the hot kiln exit gases, and away from waste heat boilers as the principal method of heat recovery. The most important gas-side fouling mechanisms in the cement industry are those due to particulate, chemical reaction, and corrosion fouling.

  15. Tendencias gerenciales y la gestión universitaria

    Directory of Open Access Journals (Sweden)

    Thaís Ferrer

    2004-01-01

    Full Text Available El propósito de la investigación consiste en determinar las tendencias gerenciales contemporáneas que aplica la alta gerencia universitaria de la Universidad del Zulia (LUZ, en su gestión para la toma de decisiones en las instituciones de educación superior, cuyos retos científicos y tecnológicos son cada día mayores en el contexto competitivo de las organizaciones. La investigación sigue la modalidad de carácter descriptivo aplicada. La población objeto de estudio fue clasificada como población censal, por sus características definitorias incluye a las autoridades universitarias, rectorales y decanales. Los resultados fueron analizados mediante distribución de frecuencias. Con los datos obtenidos se concluyó que la planificación estratégica se aplica en un 100%, la calidad total con un 68.4%, la reingeniería con el 31.6% y el benchmarking con el 26.3%. Las tendencias no utilizadas fueron el empowerment, la organización virtual y el cuadro de mando integral. La generación de lineamientos para la gerencia deseable de la alta gerencia universitaria, incluye: liderazgo, manejo de herramientas tecnológicas, capacitación profesional y gerenciar con técnicas contemporáneas. Se determina que sí existe viabilidad institucional para aplicar las propuestas. La investigación arrojó aportes significativos rompiendo el paradigma de investigar la alta gerencia de LUZ, generando el perfil de la gerencia deseable, recomendándose la aplicación de las tendencias gerenciales contemporáneas ajustándose a la naturaleza y momento presente y futuro de la organización.

  16. Los sucesos aleatorios: tendencias en los libros de texto

    OpenAIRE

    Serradó, Ana; Cardeñoso, José María; Azcaráte, Pilar

    2008-01-01

    En este trabajo se presentan los resultados correspondientes al análisis de contenido sobre la noción de suceso que se refleja en las unidades dedicadas al “Tratamiento del Azar” en una muestra de libros de texto de Educación Secundaria Obligatoria. Dicho análisis se refiere a cómo es caracterizada teóricamente la idea de suceso, qué actividades se proponen y cómo se organizan e introducen ambos elementos. Se establecen dos tendencias diferenciadas al introducir la noción de suceso, tradicion...

  17. Nuevas tendencias en el sector aeroespacial: Space Situational Awareness

    OpenAIRE

    Hermoso Garnica, José María

    2016-01-01

    La conferencia "Nuevas tendencias en el sector aeroespacial: Space Situational Awareness", impartida por el experto José María Hermoso Garnica (INDRA Espacio, ex-ESA, ...) se centra en el nuevo escenario que surge en los últimos meses en torno al Space Situational Awareness. Se examinan las múltiples tecnologías implicadas en el desarrollo de esta nueva línea de investigación, prioritaria para la UE y sus programas de financiación. Finalmente, se hace una especial revisión del tema de la basu...

  18. Development of nanosilica bonded monetite cement from egg shells

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Huan, E-mail: huanzhou@cczu.edu.cn [Institute of Biomedical Engineering and Health Sciences, Changzhou University, Changzhou, Jiangsu (China); Department of Mechanical, Industrial and Manufacturing Engineering, The University of Toledo, Toledo, OH (United States); Luchini, Timothy J.F.; Boroujeni, Nariman Mansouri [Department of Mechanical, Industrial and Manufacturing Engineering, The University of Toledo, Toledo, OH (United States); Agarwal, Anand K.; Goel, Vijay K. [Department of Bioengineering, The University of Toledo, Toledo, OH (United States); Bhaduri, Sarit B. [Department of Mechanical, Industrial and Manufacturing Engineering, The University of Toledo, Toledo, OH (United States); Division of Dentistry, The University of Toledo, Toledo, OH (United States)

    2015-05-01

    This work represents further effort from our group in developing monetite based calcium phosphate cements (CPC). These cements start with a calcium phosphate powder (MW-CPC) that is manufactured using microwave irradiation. Due to the robustness of the cement production process, we report that the starting materials can be derived from egg shells, a waste product from the poultry industry. The CPC were prepared with MW-CPC and aqueous setting solution. Results showed that the CPC hardened after mixing powdered cement with water for about 12.5 ± 1 min. The compressive strength after 24 h of incubation was approximately 8.45 ± 1.29 MPa. In addition, adding colloidal nanosilica to CPC can accelerate the cement hardening (10 ± 1 min) process by about 2.5 min and improve compressive strength (20.16 ± 4.39 MPa), which is more than double the original strength. The interaction between nanosilica and CPC was monitored using an environmental scanning electron microscope (ESEM). While hardening, nanosilica can bond to the CPC crystal network for stabilization. The physical and biological studies performed on both cements suggest that they can potentially be used in orthopedics. - Highlights: • Cement raw powder is derived from egg shells. • A microwave assisted system is used for preparing monetite bone cement. • Colloidal silica is used to reinforce cement.

  19. CO2 Capture for Cement Technology

    OpenAIRE

    2013-01-01

    Production of cement is an energy intensive process and is the source of considerable CO2emissions. Itis estimated that the cement industry contributes around 8% of total global CO2emissions. CO2is oneof the major greenhouse gases. In the atmosphere, the CO2concentration has increased from 310 ppmvin 1960 to 390 ppmv in 2012, probably due to human activity. A lot of research is being carried out forreducing CO2emissions from large stationary sources. Ofwhich, the carbonate looping process is ...

  20. Effect of Heavy Metal Present in Cement Dust on Soil and Plants of Nokha (Bikaner)

    OpenAIRE

    Dr.(Mrs).Suruchi Gupta; Sarika Sharma

    2013-01-01

    In Nokha(Bikaner) cement industries emittes cement dust in nearby farmers fields. In these industries cement dust emitted contains traces of hexavalent chromium and lead well above permissible limit in area under investigation. However, cadmium and nickel were found below limits prescribed. To analyse heavy metals viz, Cr+6, lead, Cadmium and nickel one hundred and twenty samples were collected from four directions on surface and 20 cm depth, and analyzed on atomic absorption spectrophotomete...

  1. ULTRA-LIGHTWEIGHT CEMENT

    Energy Technology Data Exchange (ETDEWEB)

    Fred Sabins

    2002-01-23

    The objective of this project is to develop an improved ultra-lightweight cement using ultra-lightweight hollow glass spheres (ULHS). This report includes results from laboratory testing of ULHS systems along with other lightweight cement systems: foamed and sodium silicate slurries. Comparison studies of the three cement systems examined several properties: tensile strength, Young's modulus, water permeability, and shear bond. Testing was also done to determine the effect that temperature cycling has on the shear bond properties of the cement systems. In addition, analysis was carried out to examine alkali silica reactivity of slurries containing ULHS. Data is also presented from a study investigating the effects of mixing and pump circulation on breakage of ULHS. Information is also presented about the field application of ULHS in cementing a 7-in. intermediate casing in south Texas.

  2. Tendencia Suicida en Niños Accidentados

    Directory of Open Access Journals (Sweden)

    Renata Paula Morais dos Santos

    Full Text Available Resumen La investigación intentó comprender los accidentes infantiles, considerando que esos eventos son, casi siempre, el resultado concreto de una denuncia de situaciones conflictivas y que pasan por hechos «ocasionales». Así, el objetivo fue investigar la posible tendencia suicida en niños entre los 6 y 12 años, hospitalizados en el Hospital da Restauração (Recife – PE/Brasil, por accidentes domésticos. Para el levantamiento de datos se utilizó un guion de entrevista semiestructurada, de carácter personal y familiar, destinado al niño y a su representante, como también la elaboración del Dibujo de la Familia, por parte del propio niño. Tras el análisis general de los resultados, puede afirmarse que, en los actos accidentales, aun cuando ocasionados por terceros, estaría reprimida una tendencia al suicidio. Los resultados indicaron una variedad de condicionantes personales y, principalmente, familiares, que pueden poner a los niños frente a un comportamiento de riesgo autodestructivo a corto y largo plazo.

  3. Utilization of waste heat from rotary kiln for burning clinker in the cement plant

    OpenAIRE

    2016-01-01

    Cement subsector next to the glass industry is counted among one of the most energy-intensive industries, which absorbs approx. 12-15% of the total energy consumed by the industry. In the paper various methods of energy consumption reduction of in the cement industry are discussed. Cement production carries a very large emissions of greenhouse gases, where CO2 emissions on a global scale with the industry than approx. 5%. Great opportunity in CO2 emissions reduction in addition to the recover...

  4. Modified-sulfur cements for use in concretes, flexible pavings, coatings, and grouts

    Science.gov (United States)

    McBee, W. C.; Sullivan, T. A.; Jong, B. W.

    1981-05-01

    A family of modified-sulfur cements was developed for the preparation of construction materials with improved properties. Various types of sulfur cements were prepared by reacting sulfur with mixtures of dicyclopentadiene and oligomers of cyclopentadiene. Durable cements were prepared with structural characteristics ranging from rigid to flexible. These cements were used to prepare corrosion-resistant materials for use in a wide variety of industrial applications where resistance to acidic and salt conditions is needed. These materials were prepared as rigid concretes, flexible pavings, spray coatings, and grouts. Production of modified-sulfur cements in a commercial-size plant was demonstrated.

  5. Destruction of meat and bone meals in cement plants; Destruction des farines animales dans les cimenteries

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    2001-10-01

    Following the crisis of the bovine spongiform encephalopathy disease ('mad cow' disease), the French cement industrialists have been requested by the government since 1996 to eliminate the forbidden meat and bone meals in cement kilns where they are used as fuel substitutes. This article presents the advantages of the cement industry file in the destruction of such wastes, the validation and the safety aspects of this process. Meat and bone meal represents a high-grade fuel that lowers the environmental impact of cement production and does not affect the quality of cement. (J.S.)

  6. Factors affecting bond cement across casing leak zones in oil and gas wells

    Energy Technology Data Exchange (ETDEWEB)

    Nasr, Mohamed; Edbeib, Said [Al-Fateh University, Tripoli (Libyan Arab Jamahiriya). Dept. of Petroleum Engineering

    2004-07-01

    Casing leaks have been a major concern to the oil industry because of their effect on lowering the production rate in many oil and gas wells. The leaks are the result of deterioration of the casing in the well, which is caused by severe corrosion due to the contact of the casing with high salinity foreign fluid. The objective of this study is to determine the factors influencing the mechanical properties of the hardened cement opposite the casing leak zones. This study is conducted by laboratory measurements of the compressive strength of the hardened cement when the cement slurry was mixed with different percentages of formation water and different concentrations of different cement additives. The results of this study indicate that the compressive strength readings obtained from the cement bond log and the cement evaluation tool against the casing leak zones are lower than those readings recorded in adjacent formations. The low cement compressive strength values observed across casing leak zones are due to the contamination of the cement with saline water present in these formations which, in turn, effects the hardening properties of the cement. The experimental results indicated that the salinity of the formation water when mixed with the cement slurry in the presence of cement additives, decreased the compressive strength of the bond cement and also decreased the thickening time of the cement slurry. It is concluded that casing leaks found in many wells observed in oil fields in Libya were due to the mixing of the cement with high salinity formation water present in the lost circulation zones. The high water salinity in these zones effects the setting time of the cement slurry which, therefore, decreased the hardening properties of the bond cement and caused cracks and channels in the hardened cement across lost circulation zones. (author)

  7. Tympanoplasty with ionomeric cement

    DEFF Research Database (Denmark)

    Kjeldsen, A D; Grøntved, A M

    2000-01-01

    with isolated erosion of the long incus process have been treated with a new surgical technique in which the ossicular chain was rebuilt with ionomeric cement. The results in hearing performance (mean pure-tone average (PTA) 0.5, 1 and 2 kHz) were evaluated pre- and post-surgery, and compared to those...... of > 10 dB, in 4 there was a slight improvement and in 2 a decline. The difference was not statistically significant. Hearing improvement using ionomeric cement in type II tympanoplasty was satisfactory. Reconstruction of the ossicular chain with ionomeric cement is recommended, as the procedure is easy...

  8. Cement and concrete

    Science.gov (United States)

    Corley, Gene; Haskin, Larry A.

    1992-01-01

    To produce lunar cement, high-temperature processing will be required. It may be possible to make calcium-rich silicate and aluminate for cement by solar heating of lunar pyroxene and feldspar, or chemical treatment may be required to enrich the calcium and aluminum in lunar soil. The effects of magnesium and ferrous iron present in the starting materials and products would need to be evaluated. So would the problems of grinding to produce cement, mixing, forming in vacuo and low gravity, and minimizing water loss.

  9. Maximizing the Sustainability of Cement Utilization in Building Projects through the Use of Greener Materials

    Directory of Open Access Journals (Sweden)

    Mark Bediako

    2016-01-01

    Full Text Available Greener technologies and sustainable developments are currently among the main tools used by many industries in shaping the world for a better future. The construction industry that is known to have numerous negative impact on sustainability is now wide awake on sustainable measures which can aid in reducing its negative impact. In this work, green cement was produced from pyroprocessed clay (PC at 800°C and mixed together with Portland cement. This paper presents both laboratory tests and some field applications of green cement application. Laboratory tests performed included setting times, compressive strength, and shrinkage. Field applications of the green cement are shown. Results from the work showed that well-proportioned greener cement gained strengths between 11% and 30% more than Portland cement at standard curing period of 3, 7, 14, and 28 days. However, in real statistical terms, there was no difference between Portland cement and green cement strength performance. Shrinkage from both total and autogenous tests also showed insignificant differences between the two cements. The study recommends the use of green cements with pozzolanic origin than only Portland cement as a way to maximize sustainability in building projects.

  10. Combustion of solid alternative fuels in the cement kiln burner

    DEFF Research Database (Denmark)

    Nørskov, Linda Kaare

    In the cement industry there is an increasing environmental and financial motivation for substituting conventional fossil fuels with alternative fuels, being biomass or waste derived fuels. However, the introduction of alternative fuels may influence emissions, cement product quality, process...... stability, and process efficiency. Alternative fuel substitution in the calciner unit has reached close to 100% at many cement plants and to further increase the use of alternative fuels rotary kiln substitution must be enhanced. At present, limited systematic knowledge of the alternative fuel combustion...... modelling, data collection and observations at an industrial cement plant firing alternative fuels. Alternative fuels may differ from conventional fossil fuels in combustion behaviour through differences in physical and chemical properties and reaction kinetics. Often solid alternative fuels are available...

  11. Utilization of waste tires as alternative fuel in cement plant

    OpenAIRE

    2016-01-01

    Cement industry is regulated by legislation in which various measures are specified for prevention and reduction of air pollution as well as protection of human health, due to atmospheric emissions, which occur during cement production. Legislation also holds emission limit values for co-incineration of wastes i.e. alternative fuels. Waste tires as an alternative fuel can be co-incinerated i.e. co-processed in cement plants, where the high calorific value of the rubber is used to substitute f...

  12. Energy optimization and reduction of carbon footprint in cement manufacturing

    Energy Technology Data Exchange (ETDEWEB)

    Gallestey, Eduardo; Crosley, Gabriela; Wilson, Andrew; Maier, Urs; Hoppler, Rolf; Boerrnert, Thomas

    2010-09-15

    Cement producers are large consumers of thermal and electrical energy, which are only available at steadily increasing costs. Efforts to reduce demands by using higher efficiency equipment and substituting -fuels and raw materials to lower production costs have been addressed in recent years. Under the Kyoto Protocol industrialised countries agreed to reduce their collective greenhouse gas emissions. Cement producers as some of the largest emitters of CO2 have been especially challenged to find new and innovative ways to reduce greenhouse gas emissions. This paper summarise some ABB technologies developed to assist the cement industry to meet these goals.

  13. The effect of fly ash and coconut fibre ash as cement replacement materials on cement paste strength

    Science.gov (United States)

    Bayuaji, R.; Kurniawan, R. W.; Yasin, A. K.; Fatoni, H. AT; Lutfi, F. M. A.

    2016-04-01

    Concrete is the backbone material in the construction field. The main concept of the concrete material is composed of a binder and filler. Cement, concrete main binder highlighted by environmentalists as one of the industry are not environmentally friendly because of the burning of cement raw materials in the kiln requires energy up to a temperature of 1450° C and the output air waste CO2. On the other hand, the compound content of cement that can be utilized in innovation is Calcium Hydroxide (CaOH), this compound will react with pozzolan material and produces additional strength and durability of concrete, Calcium Silicate Hydrates (CSH). The objective of this research is to explore coconut fibers ash and fly ash. This material was used as cement replacement materials on cement paste. Experimental method was used in this study. SNI-03-1974-1990 is standard used to clarify the compressive strength of cement paste at the age of 7 days. The result of this study that the optimum composition of coconut fiber ash and fly ash to substitute 30% of cement with 25% and 5% for coconut fibers ash and fly ash with similar strength if to be compared normal cement paste.

  14. Effect of duration of exposure to cement dust on respiratory function of non-smoking cement mill workers.

    Science.gov (United States)

    Meo, Sultan Ayoub; Al-Drees, Abdul Majeed; Al Masri, Abeer A; Al Rouq, Fawzia; Azeem, Muhammad Abdul

    2013-01-16

    This study aimed to determine the effect of long term exposure to cement dust on lung function in non-smoking cement mill workers. This is a cross-sectional study of respiratory functions. Spirometry was performed in 100 apparently healthy volunteers; 50 non-smoking cement mill workers and 50 non-smoking un-exposed subjects. Based on the duration of exposure, cement mill workers were divided into three groups, less than 5, 5-10 and greater than 10 years. All subjects were individually matched for age, height, weight, and socioeconomic status. Pulmonary function test was performed by using an electronic spirometer. Significant reduction was observed in the mean values of Forced Vital Capacity (FVC), Forced Expiratory Volume in one second (FEV(1)), Peak Expiratory Flow (PEF) and Maximal Voluntary Ventilation in cement mill workers who had been working in the cement industry for more than 10 years compared to their matched un-exposed group. Lung functions in cement mill workers were significantly impaired and results show a long term duration response effect of years of exposure to cement dust on lung functions.

  15. Design of Digital Control System for Cement Raw Material Preparation

    Institute of Scientific and Technical Information of China (English)

    ZHOU Ying; LI Hongsheng

    2006-01-01

    This paper describes the design of cement raw material prepared digital control system by PROFIBUS. It uses the digital technology to implement the digital control system for raw material prepared of the cement factory. This system improves the communication between the industrial system and locale instrument devices. It applies digital communication to replace the 4-20 mA or 24VDC signal between locale lever device and controller.

  16. Type 2 diabetes in Mexican workers exponed to a potential source of dioxins in the cement industry determined by a job exposure matrix Diabetes tipo 2 en trabajadores Mexicanos expuestos a una fuente potencial de dioxinas en la industria del cemento determinado a través de una matriz de exposición ocupacional

    Directory of Open Access Journals (Sweden)

    Luis Haro-García

    2010-06-01

    Full Text Available Purpose: To identify association between type 2 diabetes (DM2 with occupational exposure to potential dioxins source in Mexican cement industry workers. Materials and Methods: 56 medical files of cement industry workers with diagnosis of DM2 were included; 56 medical files of workers from the same industry without DM2 were the controls. The daily dose of exposure (DDE to the potential dioxins source per work years was estimated by a job exposure matrix and categorized as low, moderate, and high. Logistic regression model that correlated high exposure to potential source of dioxins (cement clinker confinement per work years and presence of DM2 was adjusted by work seniority, patient age at which DM2 diagnosis was established and DM2 familiar background. Results: the OR for the presence of DM2 in workers with moderate and high exposure to potential source of dioxins in the cement industry was 3.25 (1.10-9.57, p= 0.03, adjusted by work seniority, worker age at which DM2 diagnosis was established, and DM2 familiar background. Conclusions: In according with the data explored in the medical files of cement industry workers, there is an association between high exposure to the industrial confinement of the cement clinker as a potential source of dioxins and presence of DM2 in a modest dose-response gradient.Propósito: Identificar asociación entre diabetes tipo 2 (DM2 en trabajadores Mexicanos con la exposición ocupacional a una fuente potencial de dioxinas de la industria cementera. Material y métodos: Se incluyeron 56 expedientes clínicos de trabajadores de la industria cementera con diagnóstico de DM2; los controles lo constituyeron 56 expedientes clínicos de trabajadores de la misma industria pero sin DM2. La dosis diaria de exposición (DDE a la fuente potencial de dioxinas por años trabajados se estimó a través de una matriz de exposición ocupacional y fue categorizada como baja, moderada y alta. El modelo de regresión logística que

  17. Halliburton Shale Gas Well Cementing Technology and Its Enlightenment to Domestic Gas Industry%哈里伯顿页岩气固井技术及对国内的启示

    Institute of Scientific and Technical Information of China (English)

    齐奉忠; 杜建平

    2015-01-01

    针对国内页岩气水平井固井套管安全下入难度大,高密度油基钻井液条件下提高顶替效率及改变界面润湿性困难,对水泥石力学性能要求高等问题,本文对哈里伯顿公司页岩气固井相关技术进行了深入调研及分析,重点介绍了提高顶替效率的模拟软件,保证长期密封的水泥浆体系及配套技术,低伤害和防漏失固井技术,保证套管安全下入的工具等,并对Haynesville页岩气藏应用的固井技术进行了总结,期望据此对提高国内页岩气固井质量及技术攻关起到一定的借鉴指导作用.%It is difficult for casings to run safely into a horizontal shale gas well during cementing operations, and by taking into account of difficulties in improving the displacement efficiency and changing the interface wettability under conditions where the oil-based drilling fluids are of high density, high-level requirements on mechanical properties of cement slurry, etc. According to current characteristics and difficulties of shale gas well cementing in China, so as to further improve the shale gas well cementing quality, the in-depth research and analysis of shale gas well cementing-related technologies of Hal-liburton have been conducted, focusing on the description of the simulation software that improves displacement efficiency, the cement slurry system and supporting technology that ensure a long-term sealing ability, the cementing technology charac-terized by low damage and leakage control, the tools that ensure safe casing running, etc. , and the cementing techniques ap-plied for Haynesville shale gas reservoir have been summarized. The analysis shows that shale gas well cementing technologies overseas move toward the technology with characteristics of bundle, serialization, customization, integration, and the assur-ance of wellbore sealing and long-term sealing&isolation. By combining with development trends of shale gas well cementing technologies overseas

  18. Clean Development Mechanism: Laterite as Supplementary Cementing Material (SCM

    Directory of Open Access Journals (Sweden)

    Syed Zaighum Abbass

    2013-02-01

    Full Text Available Carbon dioxide (CO2 a major Green House Gas (GHG in the atmosphere, is believed to be largely responsible for global climate change through industrial emissions. The level of CO2 concentration has exponentially increased from about 280 ppm at the start of the industrial revolution to about 380 ppm to date. Although Kyoto protocol has bound industrialized nations to reduce green house gas emissions by 5.2% below 1990 levels around year 2008-2012, but violation continues. The cement industry is one of the major emitter of green house gases, particularly CO2 due to its energy intensive production process. It is estimated that approximately 1 tone of CO2 is released during the manufacturing of each tone of Portland cement. Most of CO2 emissions originate from burning fossil fuels and de-carbonization of limestone in a cement plant. During past several decades, the use of by-product materials in concrete, either as components of blended cements or as admixtures, has increased significantly. In this study, another alternate Supplementary Cementing Material (SCM, Laterite has been used with the objectives: to evaluate the performance of cement containing different percentages of laterite (5, 10, 15, 20, 25, and 30 %; to identify the optimum replacement percentage; and to investigate the effects of different concentrations of laterite on various properties of cement. For that purpose, laterite was tested: before blending (for elemental and mineralogical composition by using XRF, SEM and XRD: after blending (Elemental analysis using XRF, fineness test by using Blaine’s air permeability test and for particle size % on 45, 90 and 200 µ sieve, respectively; and after hydration (for mineralogical analysis using SEM. Furthermore, physical tests of manufactured cement, i.e., water consistency, setting time, Le-Chatlier-expansion and compressive strength were also evaluated and compared with limestone and fly-ash cement blends. The results show that with the

  19. ULTRA-LIGHTWEIGHT CEMENT

    Energy Technology Data Exchange (ETDEWEB)

    Fred Sabins

    2001-10-23

    The objective of this project is to develop an improved ultra-lightweight cement using ultra-lightweight hollow glass spheres (ULHS). Work reported herein addresses tasks performed in the fourth quarter as well as the other three quarters of the past year. The subjects that were covered in previous reports and that are also discussed in this report include: Analysis of field laboratory data of active cement applications from three oil-well service companies; Preliminary findings from a literature review focusing on problems associated with ultra-lightweight cements; Summary of pertinent information from Russian ultra-lightweight cement literature review; and Comparison of compressive strengths of ULHS systems using ultrasonic and crush methods Results reported from the fourth quarter include laboratory testing of ULHS systems along with other lightweight cement systems--foamed and sodium silicate slurries. These comparison studies were completed for two different densities (10.0 and 11.5 lb/gal) and three different field application scenarios. Additional testing included the mechanical properties of ULHS systems and other lightweight systems. Studies were also performed to examine the effect that circulation by centrifugal pump during mixing has on breakage of ULHS.

  20. Kinetics of strength gain of biocidal cements

    Directory of Open Access Journals (Sweden)

    Rodin Aleksandr Ivanovich

    Full Text Available Biocorrosion becomes the determinative durability factor of buildings and constructions. Damages of construction materials caused by bacteria, filamentous fungi, actinomycetes constitute a serious danger to the constructions of a building or a structure and to the health of people. Biodeteriorations are typical both in old and new constructions. A great quantity of destruction factors of industrial and residential buildings under the influence of microorganisms was established in practice. Providing products and constructions based on concretes fungicidal and bactericidal properties is an important direction of modern construction material science. The most efficient way to solve this task is creation of biocidal cements. The article presents the results of experimental studies of kinetic dependences of strength gain by biocidal cements by physico-mechanical and physico-chemical analysis methods. The identical velocity character of initial hydration of the developed compositions of biocidal cements is set, as well as a more calm behavior of hardening processes at later terms. It has been established that the compositions of biocidal cements modified by sodium sulfate and sodium fluoride possess the greatest strength.

  1. Utilization of Palm Oil Clinker as Cement Replacement Material

    Directory of Open Access Journals (Sweden)

    Jegathish Kanadasan

    2015-12-01

    Full Text Available The utilization of waste materials from the palm oil industry provides immense benefit to various sectors of the construction industry. Palm oil clinker is a by-product from the processing stages of palm oil goods. Channelling this waste material into the building industry helps to promote sustainability besides overcoming waste disposal problems. Environmental pollution due to inappropriate waste management system can also be drastically reduced. In this study, cement was substituted with palm oil clinker powder as a binder material in self-compacting mortar. The fresh, hardened and microstructure properties were evaluated throughout this study. In addition, sustainability component analysis was also carried out to assess the environmental impact of introducing palm oil clinker powder as a replacement material for cement. It can be inferred that approximately 3.3% of cement production can be saved by substituting palm oil clinker powder with cement. Reducing the utilization of cement through a high substitution level of this waste material will also help to reduce carbon emissions by 52%. A cleaner environment free from pollutants can be created to ensure healthier living. Certain industries may benefit through the inclusion of this waste material as the cost and energy consumption of the product can be minimized.

  2. PART II. HYDRATED CEMENTS

    Directory of Open Access Journals (Sweden)

    Milan Drabik

    2014-09-01

    Full Text Available Essential focus of the study has been to acquire thermoanalytical events, incl. enthalpies of decompositions - ΔH, of technological materials based on two types of Portland cements. The values of thermoanalytical events and also ΔH of probes of technological compositions, if related with the data of a choice of minerals of calcium-silicate-sulfate-aluminate hydrates, served as a valued input for the assessment of phases present and phase changes due to the topical hydraulic processes. The results indicate mainly the effects of "standard humidity" or "wet storage" of the entire hydration/hydraulic treatment, but also the presence of cement residues alongside calcium-silicate-sulfate-aluminate hydrates (during the tested period of treatment. "A diluting" effect of unhydrated cement residues upon the values of decomposition enthalpies in the studied multiphase system is postulated and discussed

  3. PURIFIED WASTE FCC CATALYST AS A CEMENT REPLACEMENT MATERIAL

    Directory of Open Access Journals (Sweden)

    Danute Vaiciukyniene

    2015-06-01

    Full Text Available Zeolites are commonly used in the fluid catalytic cracking process. Zeolite polluted with oil products and became waste after some time used. The quantity of this waste inevitably rises by expanding rapidly oil industry. The composition of these catalysts depends on the manufacturer and on the process that is going to be used. The main factors retarding hydration process of cement systems and modifying them strength are organic compounds impurities in the waste FCC catalyst. The present paper shows the results of using purified waste FCC catalyst (pFCC from Lithuania oil refinery, as Portland cement replacement material. For this purpose, the purification of waste FCC catalyst (FCC samples was treated with hydrogen peroxide. Hydrogen peroxide (H2O2 is one of the most powerful oxidizers known. By acting of waste with H2O2 it can eliminate the aforementioned waste deficiency, and the obtained product becomes one of the most promising ingredients, in new advanced building materials. Hardened cement paste samples with FCC or pFCC were formed. It was observed that the pFCC blended cements developed higher strength, after 28 days, compared to the samples with FCC or reference samples. Typical content of Portland cement substituting does not exceed 30 % of mass of Portland cement in samples. Reducing the consumption of Portland cement with utilizing waste materials is preferred for reasons of environmental protection.

  4. The mechanical effect of the existing cement mantle on the in-cement femoral revision.

    LENUS (Irish Health Repository)

    Keeling, Parnell

    2012-08-01

    Cement-in-cement revision hip arthroplasty is an increasingly popular technique to replace a loose femoral stem which retains much of the original cement mantle. However, some concern exists regarding the retention of the existing fatigued and aged cement in such cement-in-cement revisions. This study investigates whether leaving an existing fatigued and aged cement mantle degrades the mechanical performance of a cement-in-cement revision construct.

  5. Cementing a wellbore using cementing material encapsulated in a shell

    Energy Technology Data Exchange (ETDEWEB)

    Aines, Roger D.; Bourcier, William L.; Duoss, Eric B.; Floyd, III, William C.; Spadaccini, Christopher M.; Vericella, John J.; Cowan, Kenneth Michael

    2017-03-14

    A system for cementing a wellbore penetrating an earth formation into which a pipe extends. A cement material is positioned in the space between the wellbore and the pipe by circulated capsules containing the cement material through the pipe into the space between the wellbore and the pipe. The capsules contain the cementing material encapsulated in a shell. The capsules are added to a fluid and the fluid with capsules is circulated through the pipe into the space between the wellbore and the pipe. The shell is breached once the capsules contain the cementing material are in position in the space between the wellbore and the pipe.

  6. Cementing a wellbore using cementing material encapsulated in a shell

    Science.gov (United States)

    Aines, Roger D.; Bourcier, William L.; Duoss, Eric B.; Spadaccini, Christopher M.; Cowan, Kenneth Michael

    2016-08-16

    A system for cementing a wellbore penetrating an earth formation into which a pipe extends. A cement material is positioned in the space between the wellbore and the pipe by circulated capsules containing the cement material through the pipe into the space between the wellbore and the pipe. The capsules contain the cementing material encapsulated in a shell. The capsules are added to a fluid and the fluid with capsules is circulated through the pipe into the space between the wellbore and the pipe. The shell is breached once the capsules contain the cementing material are in position in the space between the wellbore and the pipe.

  7. Cement og politik

    DEFF Research Database (Denmark)

    Lund, Joachim

    2012-01-01

    as well as in the public sphere. Most of the extensive job creating measures he carried out as a minister for public works necessarily involved the use of great amounts of cement – the primary produce of F.L. Smidth & Co. Gunnar Larsen thus became an easy target for Communist propaganda, picturing him...... of the Soviet Union (including an F.L. Smidth & Co. cement plant in former Estonia). He spent the last 15 months of the occupation in Sweden and was arrested after having returned to Copenhagen in May, 1945. Although a Copenhagen city court prison sentence for economic collaboration was reversed, he had...

  8. 78 FR 10005 - National Emission Standards for Hazardous Air Pollutants for the Portland Cement Manufacturing...

    Science.gov (United States)

    2013-02-12

    ... Standards for Hazardous Air Pollutants for the Portland Cement Manufacturing Industry and Standards of Performance for Portland Cement Plants; Final Rule #0;#0;Federal Register / Vol. 78 , No. 29 / Tuesday... RIN 2060-AQ93 National Emission Standards for Hazardous Air Pollutants for the Portland...

  9. Environmental Assessment of Different Cement Manufacturing Processes Based on Emergy and Ecological Footprint Analysis

    Science.gov (United States)

    Due to its high environmental impact and energy intensive production, the cement industry needs to adopt more energy efficient technologies to reduce its demand for fossil fuels and impact on the environment. Bearing in mind that cement is the most widely used material for housin...

  10. Osteotransductive bone cements.

    Science.gov (United States)

    Driessens, F C; Planell, J A; Boltong, M G; Khairoun, I; Ginebra, M P

    1998-01-01

    Calcium phosphate bone cements (CPBCs) are osteotransductive, i.e. after implantation in bone they are transformed into new bone tissue. Furthermore, due to the fact that they are mouldable, their osteointegration is immediate. Their chemistry has been established previously. Some CPBCs contain amorphous calcium phosphate (ACP) and set by a sol-gel transition. The others are crystalline and can give as the reaction product dicalcium phosphate dihydrate (DCPD), calcium-deficient hydroxyapatite (CDHA), carbonated apatite (CA) or hydroxyapatite (HA). Mixed-type gypsum-DCPD cements are also described. In vivo rates of osteotransduction vary as follows: gypsum-DCPD > DCPD > CDHA approximately CA > HA. The osteotransduction of CDHA-type cements may be increased by adding dicalcium phosphate anhydrous (DCP) and/or CaCO3 to the cement powder. CPBCs can be used for healing of bone defects, bone augmentation and bone reconstruction. Incorporation of drugs like antibiotics and bone morphogenetic protein is envisaged. Load-bearing applications are allowed for CHDA-type, CA-type and HA-type CPBCs as they have a higher compressive strength than human trabecular bone (10 MPa).

  11. Underground void filling by cemented mill tailings

    Institute of Scientific and Technical Information of China (English)

    Choudhary Bhanwar Singh; Kumar Santosh

    2013-01-01

    Underground mining always create voids. These voids can cause subsidence of surface. So it is always a demand to fill the void in such a manner that the effect of underground mining can be minimized. Void filling using mill tailings especially in metal mining is one of the best techniques. The tailings produced in milling process have traditionally been disposed in tailing ponds creating a waste disposal and environ-mental problems in terms of land degradation, air and water pollution, etc. This disposal practice is more acute in the metal milling industry where the fine grinding, required for value liberation, results in the production of very fine tailings in large percentage. This paper includes discussions on the effectiveness of different paste mixes with varying cement contents in paste backfilling operations. The results revealed that material composition and use of super plasticizer strongly influenced the strength of cemented backfill.

  12. Effect of Heavy Metal Present in Cement Dust on Soil and Plants of Nokha (Bikaner

    Directory of Open Access Journals (Sweden)

    Dr.(Mrs.Suruchi Gupta

    2013-08-01

    Full Text Available In Nokha(Bikaner cement industries emittes cement dust in nearby farmers fields. In these industries cement dust emitted contains traces of hexavalent chromium and lead well above permissible limit in area under investigation. However, cadmium and nickel were found below limits prescribed. To analyse heavy metals viz, Cr+6, lead, Cadmium and nickel one hundred and twenty samples were collected from four directions on surface and 20 cm depth, and analyzed on atomic absorption spectrophotometer. From the above study it is clear that in case of Sarvottam cement works only lead content was higher in all directions and depths than other two plants. At tiger and Nokha cement works contamination of lead was more over limited in the first 1 km except in east direction. Mobility of lead was relatively more on top soil than 20cm depth. Hexavalent chromium content in south western direction was more for Nokha cement. Whereas, it was more in east direction in case of tiger cement. This indicated influence of prevailing direction of wind on distribution of heavy metals present in cement dust.Heavy metal toxicity results in reduction in plant height, burning of leaf margins and tip, slow leaf growth and over all wilting of Prosopis cineraria, Pearlmillet and clusterbean plants, when this metal deposits in Human body results in genetic disorders. Electrostatic precipitator can be installed to reduce the cement dust emission.

  13. Mineral resource of the month: hydraulic cement

    Science.gov (United States)

    van Oss, Hendrik G.

    2012-01-01

    Hydraulic cements are the binders in concrete and most mortars and stuccos. Concrete, particularly the reinforced variety, is the most versatile of all construction materials, and most of the hydraulic cement produced worldwide is portland cement or similar cements that have portland cement as a basis, such as blended cements and masonry cements. Cement typically makes up less than 15 percent of the concrete mix; most of the rest is aggregates. Not counting the weight of reinforcing media, 1 ton of cement will typically yield about 8 tons of concrete.

  14. Wide-scale utilization of MSWI fly ashes in cement production and its impact on average heavy metal contents in cements: The case of Austria.

    Science.gov (United States)

    Lederer, Jakob; Trinkel, Verena; Fellner, Johann

    2017-02-01

    %, which is suggested by some studies, the limit values for cements as defined by the BMLFUW (2016) will be exceeded. Furthermore, the concrete produced from this cement will not be recyclable anymore due to its high total heavy metal contents. This and the comparatively high contribution of MSWI fly ashes to total heavy metal contents in cements indicate their relatively low resource potential if compared to other secondary raw materials in the cement industry.

  15. Cement from magnesium substituted hydroxyapatite.

    Science.gov (United States)

    Lilley, K J; Gbureck, U; Knowles, J C; Farrar, D F; Barralet, J E

    2005-05-01

    Brushite cement may be used as a bone graft material and is more soluble than apatite in physiological conditions. Consequently it is considerably more resorbable in vivo than apatite forming cements. Brushite cement formation has previously been reported by our group following the mixture of nanocrystalline hydroxyapatite and phosphoric acid. In this study, brushite cement was formed from the reaction of nanocrystalline magnesium-substituted hydroxyapatite with phosphoric acid in an attempt to produce a magnesium substituted brushite cement. The presence of magnesium was shown to have a strong effect on cement composition and strength. Additionally the presence of magnesium in brushite cement was found to reduce the extent of brushite hydrolysis resulting in the formation of HA. By incorporating magnesium ions in the apatite reactant structure the concentration of magnesium ions in the liquid phase of the cement was controlled by the dissolution rate of the apatite. This approach may be used to supply other ions to cement systems during setting as a means to manipulate the clinical performance and characteristics of brushite cements.

  16. Study on the Compressive Performance of a New Type Cemented-Filling Material Based on Industrial Waste Slag and Tailings%新型工业废渣-尾矿基胶结充填材料的抗压性能研究

    Institute of Scientific and Technical Information of China (English)

    杨明录; 刘允秋

    2016-01-01

    为缓解高炉渣、尾矿等工业废渣的大量堆存对环境的危害,降低矿山开采胶结充填成本,探讨以尾矿和高炉渣、石膏、赤泥等工业废渣为主要原材料,以固体水玻璃为激活剂,制备新型工业废渣-尾矿基胶结充填材料的试验。得出最佳配方为:浆料浓度70%、灰砂比1∶3.89,高炉渣78.70%、石灰11.11%、石膏2.78%、固体水玻璃7.41%,并对高炉矿渣在胶结充填中的胶凝机理进行了研究,对尾矿资源再利用及工业生产具有重要的指导意义。%In order to alleviate the harm of the stockpiling of blast furnace slag to environment and reduce the cost mining cemented filling,the tailings,blast furnace slag,gypsum,red mud and other indus-trial waste slag are taken as the main raw materials,the solid sodium silicate is taken as the activator to conduct the experiment of producting the new cemented-filling material.The experimental results show that the optimal formular of the new cemented-filling material including slurry concentration (70%),ce-ment sand ratio (1∶3.89),blast furnance slag (78.70%),lime (11.11%),gypsum (2.78%)and sol-id sodium silicate (7.41%),besides that,the gelation mechanism of blast furnace slag in the new cemen-ted-filling material is also analyzed in detail,the above analysis results have some the important instruction significance to the resources reutilization and industrial production.

  17. Effect of cement sand ratio on industrial waste residue dry-mixed mortar properties%灰砂比对工业废渣干混砂浆性能的影响

    Institute of Scientific and Technical Information of China (English)

    刘秀伟; 杨林; 秦贤顺

    2015-01-01

    研究了高掺量磷渣粉、粉煤灰干混砂浆的灰砂比对砂浆性能的影响及激发剂对砂浆的作用机理。结果表明,在砂浆稠度基本不变的前提下,随着灰砂比减小,砂浆和易性变差,凝结时间延长,抗压强度降低,拉伸黏结强度逐渐减小,28 d干缩逐渐增大,但在灰砂比为1:1~1:6的范围内其性能均能满足GB/T 25181—2010《预拌砂浆》中对应等级标准要求,调整灰砂比可以配制出M5.0~M30不同强度等级的普通干混砂浆。%Study on the mechanism of effect of high content of phosphorus slag powder,fly ash dry mixed mortar cement sand ratio on the properties of mortar and activator on the mortar. The results show that,on the premise of mortar consistency basically unchanged, with the cement sand ratio decreases,mortar workability variation,extended the setting time,compressive strength decreases,the tensile bond strength decreases,28 d shrinking gradually increased,but in the cement sand ratio is in the range of 1:1~1:6 and its performance can meet the GB/T 25181—2010 ready mixed mortar in the corresponding grade standards,adjust the cement sand ratio can be prepared M5.0~M30 of different strength grade of ordinary dry mixed mortar.

  18. Development of nanosilica bonded monetite cement from egg shells.

    Science.gov (United States)

    Zhou, Huan; Luchini, Timothy J F; Boroujeni, Nariman Mansouri; Agarwal, Anand K; Goel, Vijay K; Bhaduri, Sarit B

    2015-05-01

    This work represents further effort from our group in developing monetite based calcium phosphate cements (CPC). These cements start with a calcium phosphate powder (MW-CPC) that is manufactured using microwave irradiation. Due to the robustness of the cement production process, we report that the starting materials can be derived from egg shells, a waste product from the poultry industry. The CPC were prepared with MW-CPC and aqueous setting solution. Results showed that the CPC hardened after mixing powdered cement with water for about 12.5±1 min. The compressive strength after 24h of incubation was approximately 8.45±1.29 MPa. In addition, adding colloidal nanosilica to CPC can accelerate the cement hardening (10±1 min) process by about 2.5 min and improve compressive strength (20.16±4.39 MPa), which is more than double the original strength. The interaction between nanosilica and CPC was monitored using an environmental scanning electron microscope (ESEM). While hardening, nanosilica can bond to the CPC crystal network for stabilization. The physical and biological studies performed on both cements suggest that they can potentially be used in orthopedics.

  19. Influence of CG With High Content of Metallic Particles as a Cement Admixture on Cement Strength

    Institute of Scientific and Technical Information of China (English)

    WAN Hui-wen; LIN Zong-shou; ZHAO Qian; HUANG Yun

    2003-01-01

    Copper gangue (CG), containing a large amount of water with grain sizes of 0.037 to 0.10mm,is an inactive industrial waste generated from copper refineries. When it is dried and used as a cement admixture, the influence of the presence of finely dispersed metallic particles in CG on the microstructure and compressive strength of cement paste has been studied.The results show that the higher the replacement of CG is,the lower the compressive strength of cement mortar is.However,the long-term strength of the specimens with 10% CG,especially after being cured for 3 months,approached to that of the plain mortar.Its mechanism was studied by an electron probe X-ray microanalyzer (EPXMA).The results indicate that a small quantity of Fe(OH)3·nH2O slowly formed from Fe2O3 in the presence of Ca(OH)2, free CaO and MgO of the clinker also slowly hydrated and formed Ca(OH)2 and Mg(OH)2 respectively,so the hardened cement paste became more compact.

  20. By-product materials in cement clinker manufacturing

    Energy Technology Data Exchange (ETDEWEB)

    Gadayev, A. [ICS and E, Aurora, CO (United States); Kodess, B. [VNIIMS Gosstandart of Russia, Moscow (Russian Federation)

    1999-02-01

    The use of Cl- and SO{sub 3}-containing by-products from chemical industries for manufacturing Portland cement clinker using a wet process was examined. The chemical and mineralogical compositions of the by-products and raw materials were determined. Homogeneous raw mixes containing different concentrations of by-products (5--30%) were prepared and the influence of the by-products on all steps of burning the mixes in a kiln to form a cement clinker was investigated. It was shown that introducing Cl- and SO{sub 3}-containing by-products to the raw mixes significantly changes all the cement clinker producing stages and changes the chemical and mineralogical compositions at all intermediate stages and in the finished products, forming new minerals containing Cl and SO{sub 3} [CaO{sub x} (SiO{sub 2}){sub y} CaCl{sub 2}] or [CaO{sub x} (SiO{sub 2}){sub y} CaSO{sub 4}] and increasing the amount of well-known intermediate minerals. The presence of the chlorides and sulfates in the cement clinker burning processes removes alkali from the raw mixes, turning them to volatile forms, accelerating the raw mineral decomposition processes and accelerating the formation processes of cement minerals (C{sub 2}S, C{sub 12}A{sub 7}, C{sub 4}AF) and formation of chloride and sulfate cycles in the kiln, forming clinker liquids and decreasing the formation and growth of the main cement minerals (C{sub 3}A, C{sub 3}S). The cement clinker contains some quantity of minerals with Cl or SO{sub 3}. Their presence in the final product decreases cement quality by reducing the amount of active CaO (C) and reducing the active CaO/SiO{sub 2} ratio.

  1. Advances in Glass Ionomer Cements

    OpenAIRE

    KAYA, Dt. Tuğba; TİRALİ, Yard. Doç. Dr. Resmiye Ebru

    2013-01-01

    In recent years there have been a number of innovations and developments with respect to glass ionomer cements and their applications in clinical dentistry. This article considers some of the recent outstanding studies regarding the field of glass ionomer cement applications, adhesion and setting mechanisms, types, advantage and disadvantages among themselves and also to enhance the physical and antibacterial properties under the title of 'Advances in Glass Ionomer Cements'. As their biologic...

  2. Cement penetration after patella venting.

    Science.gov (United States)

    Jones, Christopher W; Lam, Li-On; Butler, Adam; Wood, David J; Walsh, William R

    2009-01-01

    There is a high rate of patellofemoral complications following total knee arthroplasty. Optimization of the cement-bone interface by venting and suction of the tibial plateau has been shown to improve cement penetration. Our study was designed to investigate if venting the patella prior to cementing improved cement penetration. Ten paired cadaver patellae were allocated prior to resurfacing to be vented or non-vented. Bone mineral density (BMD) was measured by DEXA scanning. In vented specimens, a 1.6 mm Kirschner wire was used to breach the anterior cortex at the center. Specimens were resurfaced with standard Profix instrumentation and Versabond bone cement (Smith and Nephew PLC, UK). Cement penetration was assessed from Faxitron and sectioned images by a digital image software package (ImageJ V1.38, NIH, USA). Wilcoxon rank sum test was used to assess the difference in cement penetration between groups. The relationship between BMD and cement penetration was analyzed by Pearson correlation coefficient. There was a strong negative correlation between peak BMD and cement penetration when analyzed independent of experimental grouping (r(2)=-0.812, p=0.004). Wilcoxon rank sum testing demonstrated no significant difference (rank sum statistic W=27, p=0.579) in cement penetration between vented (10.53%+/-4.66; mean+/-std dev) and non-vented patellae (11.51%+/-6.23; mean+/-std dev). Venting the patella using a Kirschner wire does not have a significant effect on the amount of cement penetration achieved in vitro using Profix instrumentation and Versabond cement.

  3. Random ionic mobility on blended cements exposed to aggressive environments

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, Rosario, E-mail: rosario.garcia@uam.es [Departamento de Geologia y Geoquimica, Facultad de Ciencias, Universidad Autonoma, 28049 Madrid (Spain); Rubio, Virginia [Departamento de Geografia, Facultad de Filosofia y Letras, Universidad Autonoma, 28049 Madrid (Spain); Vegas, Inigo [Labein-Tecnalia, 48160 Derio, Vizcaya (Spain); Frias, Moises [Instituto Eduardo Torroja, CSIC, c/ Serrano Galvache, 4, 28033 Madrid (Spain)

    2009-09-15

    It is known that the partial replacement of cement by pozzolanic admixtures generally leads to modifications in the diffusion rates of harmful ions. Recent research has centred on obtaining new pozzolanic materials from industrial waste and industrial by-products and on the way that such products can influence the performance of blended cements. This paper reports the behaviour of cements blended with calcined paper sludge (CPS) admixtures under exposure to two different field conditions: sea water and cyclic changes in temperature and humidity. Cement mortars were prepared with 0% and 10% paper sludge calcined at 700 deg. C. The penetration of ions within the microstructure of cement matrices was studied using X-ray diffraction (XRD) and scanning electron microscopy equipped with an energy dispersive X-ray analyser (SEM/EDX) analytical techniques. The results show that ionic mobility varies substantially according to the type of exposure and the presence of the calcined paper sludge. The incorporation of 10% CPS is shown to assist the retention and diffusion of the ions.

  4. Influence of ferrite phase in alite-calcium sulfoaluminate cements

    Science.gov (United States)

    Duvallet, Tristana Yvonne Francoise

    Since the energy crisis in 1970's, research on low energy cements with low CO2- emissions has been increasing. Numerous solutions have been investigated, and the goal of this original research is to create a viable hybrid cement with the components of both Ordinary Portland cement (OPC) and calcium sulfoaluminate cement (CSAC), by forming a material that contains both alite and calcium sulfoaluminate clinker phases. Furthermore, this research focuses on keeping the cost of this material reasonable by reducing aluminum requirements through its substitution with iron. The aim of this work would produce a cement that can use large amounts of red mud, which is a plentiful waste material, in place of bauxite known as an expensive raw material. Modified Bogue equations were established and tested to formulate this novel cement with different amounts of ferrite, from 5% to 45% by weight. This was followed by the production of cement from reagent chemicals, and from industrial by-products as feedstocks (fly ash, red mud and slag). Hydration processes, as well as the mechanical properties, of these clinker compositions were studied, along with the addition of gypsum and the impact of a ferric iron complexing additive triisopropanolamine (TIPA). To summarize this research, the influence of the addition of 5-45% by weight of ferrite phase, was examined with the goal of introducing as much red mud as possible in the process without negatively attenuate the cement properties. Based on this PhD dissertation, the production of high-iron alite-calcium sulfoaluminateferrite cements was proven possible from the two sources of raw materials. The hydration processes and the mechanical properties seemed negatively affected by the addition of ferrite, as this phase was not hydrated entirely, even after 6 months of curing. The usage of TIPA counteracted this decline in strength by improving the ferrite hydration and increasing the optimum amount of gypsum required in each composition

  5. Estudios sobre educación intercultural en Colombia: tendencias y perspectivas

    Directory of Open Access Journals (Sweden)

    Celmira Castro Suárez

    2009-01-01

    Full Text Available En este artículo la autora da cuanta de las tendencias y perspectivas de los estudios sobre educación intercultural que se han realizado en el país en los últimos años. Para lo cual hace un recorrido por los diversas preocupaciones por parte de los estudiosos del tema, quienes desde distintas tendencias conceptuales y disciplinares han venido redefiniendo el objeto de estudio de la diversidad cultural, la cual ya no solo es abordada con elpropósito de cuantificar etnias o grupos culturales existentes, o para relacionar e inventariar sus lenguas o identificar las tendencias pedagógicas de moda en relación a lacultura.

  6. Cement plant gaseous pollutant emission reduction technologies

    Directory of Open Access Journals (Sweden)

    Andrés Emilio Hoyos Barreto

    2010-10-01

    Full Text Available A brief description of SOX, NOX and CO2 formation is presented, these being the main pollutants emitted in the cement industry gas stream Several technologies for reducing NOX, SOX and CO2 emissions in long wet kilns are introduced: primary measures preventing contaminant formation and secondary/tube end emission reduction measures. Strategies for preventing CO2 (green-house effect gas formation are also addressed, such as fuel and raw material substitution and CO2 capture technologies which are still being developed.

  7. Study the air pollution due to Dorud Cement Plant (in Iran

    Directory of Open Access Journals (Sweden)

    Vahid Mokhtari

    2016-09-01

    Full Text Available Cement industry is one of the most important industries in the country. Dorud Cement Plant is one of the largest and oldest Iran's cement factories, which is working in the center of the city of Dorud. In this study, aimed to investigate air pollution resulting from Dorud cement plant, the parameters of CO, CO2, O2, NO, NO2, NOx, SO2, dry dust particles, particles weight and environmental particulates of PM10 and PM2.5 were measured with conventional methods of measuring emissions from industrial chimneys and by using automatic measuring equipment, and the rates of emissions from the chimneys of the plant were calculated during a working year. These measurements were made over three months, from February 20, 2015 to May 21, 2015, at 3 stations of Link1-k1, Link2-k1 and Link3-k1, which are the chimneys of the three-lines of the plant. It was found in this study that the chimney No. 3 enters the maximum contaminant into the environment. The results also showed that based on the standards defined for the cement industry, Dorud cement plant meets the relative optimal conditions in terms of comparing performance with the standards, and the emissions from the factory are less than the enacted standards for this industry. Also, the preventive measures and equipment for reducing emissions established in this industrial unit have a relative utility. In this study, the factors including type of raw materials used, old production lines and old factory equipment, type of producing cement and proximity to the city were determined as main reasons for the emissions produced by this industry. Also, some management solutions such as the use of environment designing inside the manufacturing process of the plant and outside the plant, using flame-reducing, construction of a new phase and relocating the plant were suggested to reduce emissions from Dorud cement plants.

  8. Colorectal cancer and non-malignant respiratory disease in asbestos cement and cement workers. Studies on mortality, cancer morbidity, and radiographical changes in lung parenchyma and pleura

    Energy Technology Data Exchange (ETDEWEB)

    Jacobsson, K.

    1993-09-01

    Radiologically visible parenchymal changes (small opacities >= 1/0;ILO 1980 classification) were present in 20% of a sample of workers (N=174), employed for 20 years (median) in an asbestos cement plant. Exposure-response relationships were found, after controlling for age and smoking habits. In a sample of asbestos cement workers with symptoms and signs suggestive of pulmonary disease (N=33), increased lung density measured by x-ray computed tomography, and reduced static lung volumes and lung compliance was found. In a cohort of asbestos cement workers (N=1.929) with an estimated median exposure of 1.2 fibres/ml, the mortality from non-malignant respiratory disease was increased in comparison to a regional reference cohort (N=1.233). A two-to three-fold increase of non-malignant respiratory mortality was noted among workers employed for more than a decade in the asbestos cement plant, compared to cement workers (N=1.526), who in their turn did not experience and increased risk compared to the general population. In the cohorts of asbestos cement and cement workers, there was a tow-to three-fold increased incidence of cancer in the right part of the colon, compared to the general population as well as to external reference cohorts of other industrial workers (N=3.965) and fishermen (N=8.092). A causal relation with the exposure to mineral dust and fibres was supported by the findings of higher risk estimated in subgroups with high cumulated asbestos doses or longer duration of cement work. The incidence of cancer in the left part of the colon was not increased. Morbidity data, but not mortality data, disclosed the subsite-specific risk pattern. Both asbestos cement workers and cement workers has an increased incidence of rectal cancer, compared with the general population, and with the fishermen. The risk was, however, of the same magnitude among the other industrial workers. 181 refs.

  9. Thermal Shock-resistant Cement

    Energy Technology Data Exchange (ETDEWEB)

    Sugama T.; Pyatina, T.; Gill, S.

    2012-02-01

    We studied the effectiveness of sodium silicate-activated Class F fly ash in improving the thermal shock resistance and in extending the onset of hydration of Secar #80 refractory cement. When the dry mix cement, consisting of Secar #80, Class F fly ash, and sodium silicate, came in contact with water, NaOH derived from the dissolution of sodium silicate preferentially reacted with Class F fly ash, rather than the #80, to dissociate silicate anions from Class F fly ash. Then, these dissociated silicate ions delayed significantly the hydration of #80 possessing a rapid setting behavior. We undertook a multiple heating -water cooling quenching-cycle test to evaluate the cement’s resistance to thermal shock. In one cycle, we heated the 200 and #61616;C-autoclaved cement at 500 and #61616;C for 24 hours, and then the heated cement was rapidly immersed in water at 25 and #61616;C. This cycle was repeated five times. The phase composition of the autoclaved #80/Class F fly ash blend cements comprised four crystalline hydration products, boehmite, katoite, hydrogrossular, and hydroxysodalite, responsible for strengthening cement. After a test of 5-cycle heat-water quenching, we observed three crystalline phase-transformations in this autoclaved cement: boehmite and #61614; and #61543;-Al2O3, katoite and #61614; calcite, and hydroxysodalite and #61614; carbonated sodalite. Among those, the hydroxysodalite and #61614; carbonated sodalite transformation not only played a pivotal role in densifying the cementitious structure and in sustaining the original compressive strength developed after autoclaving, but also offered an improved resistance of the #80 cement to thermal shock. In contrast, autoclaved Class G well cement with and without Class F fly ash and quartz flour failed this cycle test, generating multiple cracks in the cement. The major reason for such impairment was the hydration of lime derived from the dehydroxylation of portlandite formed in the autoclaved

  10. Phosphate based oil well cements

    Science.gov (United States)

    Natarajan, Ramkumar

    The main application of the cement in an oil well is to stabilize the steel casing in the borehole and protect it from corrosion. The cement is pumped through the borehole and is pushed upwards through the annulus between the casing and the formation. The cement will be exposed to temperature and pressure gradients of the borehole. Modified Portland cement that is being used presently has several shortcomings for borehole sealant. The setting of the Portland cement in permafrost regions is poor because the water in it will freeze even before the cement sets and because of high porosity and calcium oxide, a major ingredient it gets easily affected by the down hole gases such as carbon dioxide. The concept of phosphate bonded cements was born out of considerable work at Argonne National Laboratory (ANL) on their use in stabilization of radioactive and hazardous wastes. Novel cements were synthesized by an acid base reaction between a metal oxide and acid phosphate solution. The major objective of this research is to develop phosphate based oil well cements. We have used thermodynamics along with solution chemistry principles to select calcined magnesium oxide as candidate metal oxide for temperatures up to 200°F (93.3°C) and alumina for temperatures greater than 200°F (93.3°C). Solution chemistry helped us in selecting mono potassium phosphate as the acid component for temperatures less than 200°F (93.3°C) and phosphoric acid solution greater than 200°F (93.3°C). These phosphate cements have performance superior to common Portland well cements in providing suitable thickening time, better mechanical and physical properties.

  11. Addressing Industrial Overcapacity

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    China vows to exert tougher restrictions on excess capacity and redundant construction Enterprises looking to invest in the steel, cement or plate glass sectors will find it difficult to establish operations. The government is saying "no" to any expansion into these industries.

  12. Manipulating cement-steel interface by means of electric field: Experiment and potential applications

    Directory of Open Access Journals (Sweden)

    Kamila Gawel

    2016-08-01

    Full Text Available Good shear bonding and hydraulic bonding between cement and steel play a crucial role in well integrity of oil and gas wells. In this experimental study, we investigate the effect that constant electric field may have on the bonding at cement-steel interfaces. Constant voltage (18 V was applied between two stainless-steel electrodes immersed into a cement slurry. It was found that bonding was significantly improved at the positive electrode, while it was significantly worse at the negative electrode. The effect was due to the negatively-charged cement particles being attracted to the positive electrode. The effect may potentially be used for manipulation and control of casing-cement and reinforcement-concrete bonding strengths in oil & gas and construction industries, respectively. Side-effects that might reduce the applicability of this technology, are gas production at both electrodes (and especially at the negative one and significant corrosion at the positive electrode due to electrochemical reactions at metal surfaces. Poor bonding at the negative electrode may potentially be used for cleaning of cement equipment, such as cement pumps, pipes, tanks, and mixers used on the rigs to perform well cementing jobs in oil & gas industry.

  13. A Thermoelectric Waste-Heat-Recovery System for Portland Cement Rotary Kilns

    Science.gov (United States)

    Luo, Qi; Li, Peng; Cai, Lanlan; Zhou, Pingwang; Tang, Di; Zhai, Pengcheng; Zhang, Qingjie

    2015-06-01

    Portland cement is produced by one of the most energy-intensive industrial processes. Energy consumption in the manufacture of Portland cement is approximately 110-120 kWh ton-1. The cement rotary kiln is the crucial equipment used for cement production. Approximately 10-15% of the energy consumed in production of the cement clinker is directly dissipated into the atmosphere through the external surface of the rotary kiln. Innovative technology for energy conservation is urgently needed by the cement industry. In this paper we propose a novel thermoelectric waste-heat-recovery system to reduce heat losses from cement rotary kilns. This system is configured as an array of thermoelectric generation units arranged longitudinally on a secondary shell coaxial with the rotary kiln. A mathematical model was developed for estimation of the performance of waste heat recovery. Discussions mainly focus on electricity generation and energy saving, taking a Φ4.8 × 72 m cement rotary kiln as an example. Results show that the Bi2Te3-PbTe hybrid thermoelectric waste-heat-recovery system can generate approximately 211 kW electrical power while saving 3283 kW energy. Compared with the kiln without the thermoelectric recovery system, the kiln with the system can recover more than 32.85% of the energy that used to be lost as waste heat through the kiln surface.

  14. Tendencias del tabaquismo en adultos en México entre 1988 y 2008

    OpenAIRE

    Francisco Franco-Marina; Eduardo Lazcano-Ponce

    2010-01-01

    Objetivo. Describir las tendencias, durante las pasadas dos décadas, de varios indicadores de tabaquismo y explorar si las políticas de contención de la epidemia de tabaquismo en México, implantadas desde 2004, han tenido ya un impacto favorable hacia 2008. Material y métodos. Se analizan las tendencias de datos comparables sobre la prevalencia de nunca fumadores y de fumadores diarios, utilizando las cinco encuestas nacionales de adicciones realizadas entre 1988 y 2008. En el análisis se inc...

  15. Tendencias en la calidad de vida en países con dependencia mineral

    OpenAIRE

    2009-01-01

    El presente trabajo tiene como objetivo describir tendencias a partir de algunos indicadores de calidad de vida en el conjunto de países de dependencia mineral. A partir de gráficos Box-Plot e índices de correlación, se procedió a la descripción de tendencias estadísticas para realizar precisiones en torno a la calidad de vida -analizada a través del índice de desarrollo humano [ÍDH] y componentes- y variables económicas [exportaciones minerales como porcentaje del total de exportaciones y de...

  16. Modelos y tendencias de la formación docente universitaria

    OpenAIRE

    Pilar Aramburuzabala; Reyes Hernández - Castilla; Isabel Cristina Ángel - Uribe

    2013-01-01

    El presente artículo explicita los modelos teóricos y las tendencias que subyacen a los programas de Formación del Profesorado Universitario (FPU) y propone definir planteamientos sistémicos del ámbito supra - universitario, con el fin de contribuir a profesionalizar el rol docente y mejorar la calidad de la enseñanza universitaria. Este trabajo tiene como objetivos describir los modelos, trazar las tendencias de la FPU y proponer mejoras tras la implantación del plan Bolonia. Para ello, prof...

  17. Corrosion of steel bars in cracked concrete made with ordinary portland, slag and fly ash cements

    Energy Technology Data Exchange (ETDEWEB)

    Mohammed, T.U.; Yamaji, T.; Hamada, H. [Port and Harbor Research Inst., Ministry of Land, Infrastructure and Transport (Japan); Aoyama, T. [PS Corp. (Japan)

    2001-07-01

    A study was conducted in which the marine durability of ordinary portland cement, slag and fly ash cement was examined using 15 year old plain and reinforced concrete cylindrical specimens. The performance of these cements was then examined for pre-cracked reinforced concrete prism samples. The process of manufacturing cement emits huge amounts of carbon dioxide into the global atmosphere. Replacing a portion of the cement with by-products from the steel industry and thermal power plants (which are both huge emitters of carbon dioxide) can lower carbon dioxide emissions and also solve the disposal issue of slag and fly ash while increasing the long-term durability of concrete structures. In this study, concrete cylindrical specimens were made of ordinary portland cement, slag and fly ash cements. The specimens were 100 x 100 x 600 mm prisms of different types of cement. Water-to-cement ratios were 0.45 and 0.55. Both tap water and seawater were used as mixing water. The samples were exposed in tidal pools for 15 years to evaluate the compressive strength of the concrete, corrosion of the steel bars, and chloride-ion concentrations in the concrete. It was shown that, with the exception of fly ash cements, the compressive strength of most cements increased after 15 years of exposure compared to its 28 day strength. Type C slag cement demonstrated the best performance against chloride-ion at the surface of concrete made with slag and fly ash. Voids in the steel-concrete interface make it possible for corrosion pits to develop. The use of seawater as mixing water results in earlier strength development at 28 days and does not cause to the strength of the concrete to regress after 15-years of exposure, but it causes more corrosion of steel bars at a lower cover depth. Corrosion of steel bars is not an issue at deeper cover depths. 15 refs., 19 tabs., 13 figs.

  18. Industrial Fuel Flexibility Workshop

    Energy Technology Data Exchange (ETDEWEB)

    none,

    2006-09-01

    On September 28, 2006, in Washington, DC, ITP and Booz Allen Hamilton conducted a fuel flexibility workshop with attendance from various stakeholder groups. Workshop participants included representatives from the petrochemical, refining, food and beverage, steel and metals, pulp and paper, cement and glass manufacturing industries; as well as representatives from industrial boiler manufacturers, technology providers, energy and waste service providers, the federal government and national laboratories, and developers and financiers.

  19. Utilization of waste heat from rotary kiln for burning clinker in the cement plant

    Directory of Open Access Journals (Sweden)

    Sztekler Karol

    2016-01-01

    Full Text Available Cement subsector next to the glass industry is counted among one of the most energy-intensive industries, which absorbs approx. 12-15% of the total energy consumed by the industry. In the paper various methods of energy consumption reduction of in the cement industry are discussed. Cement production carries a very large emissions of greenhouse gases, where CO2 emissions on a global scale with the industry than approx. 5%. Great opportunity in CO2 emissions reduction in addition to the recovery of waste heat is also alternative fuels co-firing in cement kilns [1], [2]. In the cement sector interest in fitting-usable waste energy is growing in order to achieve high rates of savings and hence the financial benefits, as well as the environment ones [3]. In the process of cement production is lost irretrievably lot of energy and reduction of these losses on a global scale gives a visible saving of consumed fuel. The aim of this study is to investigate the possibility of waste heat use in Rudniki Cement Plant near to Czestochowa. After analyzing of all waste heat sources will be analyzed the heat emitted by radiation from the surface of the rotary kiln at the relevant facility. On the basis of thermal-flow calculations the most favorable radiative heat exchanger will be designed. The calculations based on available measurements provided by the cement plant, a thermal power of the heat exchanger, the heat exchange surface, the geometry of the heat exchanger, and other important parameters will be established. In addition the preliminary calculations of hydraulic losses and set directions for further work will be carried out. Direct benefits observed with the introduction of the broader heat recovery technology, is a significant increase in energy efficiency of the industrial process, which is reflected in the reduction of energy consumption and costs. Indirectly it leads to a reduction of pollution and energy consumption.

  20. Energy End-Use : Industry

    NARCIS (Netherlands)

    Banerjee, R.; Gong, Y; Gielen, D.J.; Januzzi, G.; Marechal, F.; McKane, A.T.; Rosen, M.A.; Es, D. van; Worrell, E.

    2012-01-01

    The industrial sector accounts for about 30% of the global final energy use and accounts for about 115 EJ of final energy use in 2005. 1Cement, iron and steel, chemicals, pulp and paper and aluminum are key energy intensive materials that account for more than half the global industrial use. There i

  1. The polymer cement of sulfur as an alternative for the recycling of phosphogypsum. Corrosion testing of cements enriched with phosphogypsum; El cemento polimerico de azufre como alternative para el reciclado de fosfoyesos. Pruebas de corrosion de cementos enriquecidos con fosfoyesos

    Energy Technology Data Exchange (ETDEWEB)

    Gasco, C.; Lopez, F. A.; Navarro, N.; Sanchez, M.; Sanz, B.; Ballesteros, O.; Higueras, E.; Roman, C. P.

    2011-07-01

    The possibility of the use of cement for the recycling of materials is seen today as sustainable solution of the fertilizer industry for production of matches (NORM). In this paper presents some results of corrosion tests performed on these cements modified using buffer solutions of different pH. The analytical determinations in these matrices are new challenges. (Author)

  2. The interaction of pH, pore solution composition and solid phase composition of carbonated blast furnace slag cement paste activated with aqueous sodium monofluorophosphate

    NARCIS (Netherlands)

    Kempl, J.; Copuroglu, O.

    2015-01-01

    Blast Furnace Slag (BFS) is a waste product of industrial steel production and a common additive in the cement industry in Northern European countries. However, cementitious materials made from slag-rich cement, particularly CEM III /B, are very susceptible to carbonation. Recent investigations have

  3. Cemented total hip arthroplasty with Boneloc bone cement.

    Science.gov (United States)

    Markel, D C; Hoard, D B; Porretta, C A

    2001-01-01

    Boneloc cement (WK-345, Biomet Inc, Warsaw, Ind) attempted to improve cement characteristics by reducing exotherm during polymerization, lowering residual monomer and solubility, raising molecular weight, and lowering airborne monomer and aromatic amines. To study the efficacy of this cement, a selected group of 20 patients were prospectively enrolled and followed up after hip arthroplasty. All components were cemented. During the enrollment period, approximately 70 other hip arthroplasties were performed. Clinical evaluation was based on the Harris hip score. Radiographic evaluation was based on assessment of position of the components, subsidence, and/or presence of radiolucencies. Patients had follow-up for an average of 42 months (11 to 58 months); 1 was lost to follow-up. Of these, 7 (35%) had failure at last follow-up. Despite its initial promise, Boneloc cement had an unacceptably high failure rate over a relatively short follow-up period and is not recommended for use. Despite the longevity and odor toxicity problems with conventional bone cement, new cement technologies must be approached with caution.

  4. Magnesium oxychloride cement concrete

    Indian Academy of Sciences (India)

    A K Misra; Renu Mathur

    2007-06-01

    The scope of magnesium oxychloride (MOC) cement in concrete works has been evaluated. MOC cement concrete compositions of varying strengths having good placing and finishing characteristics were prepared and investigated for their compressive and flexural strengths, -values, abrasion resistance etc. The durability of MOC concrete compositions against extreme environmental conditions viz. heating–cooling, freezing–thawing, wetting–drying and penetration and deposition of salts etc were investigated. The results reveal that MOC concrete has high compressive strength associated with high flexural strength and the ratio of compressive to flexural strength varies between 6 and 8. The elastic moduli of the compositions studied are found to be 23–85 GPa and the abrasion losses between 0.11 and 0.20%. While alternate heating–cooling cycles have no adverse effect on MOC concrete, it can be made durable against freezing–thawing and the excessive exposure to water and salt attack by replacing 10% magnesium chloride solution by magnesium sulphate solution of the same concentration.

  5. Cement: a two thousand year old nano-colloid.

    Science.gov (United States)

    Ridi, Francesca; Fratini, Emiliano; Baglioni, Piero

    2011-05-15

    Since Roman times, cement is one of the synthetic materials with the largest production and usage by mankind. Its properties allowed the expansion of the Roman Empire and the building of still fascinating works. In spite of the diverse use of cement and the abundant literature accumulated during a century of systematic scientific research on this material, the understanding of its properties is still far from complete. Several issues are still open, ranging from the understanding of the hydration kinetics and the influence of the modern industrial additives, to the deep comprehension of the atomic arrangement and nanostructure of disordered hydrated calcium silicate phase (C-S-H) formed by hydration. This feature article briefly summarizes recent results in the field, highlighting the necessity for a colloidal model of the cement microstructure that, combined with the layer-like structure of the colloidal units, is the most effective approach to fully describe the characteristics of this peculiar material.

  6. Composite Control of Precalciner Exit Temperature in Cement Rotary Kiln

    Institute of Scientific and Technical Information of China (English)

    赵晨; 诸静

    2003-01-01

    A composite control strategy for the precalciner exit temperature in cement kiln is introduced based on a mathematical model. In this model, the raw meal flow, coal powder flow and wind flow are taken as three input variables, the clinker fow and exit teperature of cement kiln are output variables, and other influencing factors are considered as disturbance. A composite control system is synthesied by integrating self-learning PID, fuzzy and feedforward function into a combined controller, and the arithmetics for the self-learning PID controller, fuzzy controller and feedforward controller are elaborated respectively. The control strategy has been realized by software in real practice at cement factory. Application results show that the composite control technology is superior to the general PID control in control effect, and is suitable to the industrial process control with slow parameter variation, nonlinearity and uncertainty.

  7. Radionuclide and metal sorption on cement and concrete

    CERN Document Server

    Ochs, Michael; Wang, Lian

    2016-01-01

    Cementitious materials are being widely used as solidification/stabilisation and barrier materials for a variety of chemical and radioactive wastes, primarily due to their favourable retention properties for metals, radionuclides and other contaminants. The retention properties result from various mineral phases in hydrated cement that possess a high density and diversity of reactive sites for the fixation of contaminants through a variety of sorption and incorporation reactions. This book presents a state of the art review and critical evaluation of the type and magnitude of the various sorption and incorporation processes in hydrated cement systems for twenty-five elements relevant for a broad range of radioactive and industrial wastes. Effects of cement evolution or ageing on sorption/incorporation processes are explicitly evaluated and quantified. While the immobilisation of contaminants by mixing-in during hydration is not explicitly addressed, the underlying chemical processes are similar. A quantitativ...

  8. Emerging Energy-efficiency and CO{sub 2} Emission-reduction Technologies for Cement and Concrete Production

    Energy Technology Data Exchange (ETDEWEB)

    Hasanbeigi, Ali; Price, Lynn; Lin, Elina

    2012-04-06

    Globally, the cement industry accounts for approximately 5 percent of current anthropogenic carbon dioxide (CO{sub 2}) emissions. World cement demand and production are increasing significantly, leading to an increase in this industry's absolute energy use and CO{sub 2} emissions. Development of new energy-efficiency and CO{sub 2} emission-reduction technologies and their deployment in the market will be key for the cement industry's mid- and long-term climate change mitigation strategies. This report is an initial effort to compile available information on process description, energy savings, environmental and other benefits, costs, commercialization status, and references for emerging technologies to reduce the cement industry's energy use and CO{sub 2} emissions. Although studies from around the world identify a variety of sector-specific and cross-cutting energy-efficiency technologies for the cement industry that have already been commercialized, information is scarce and/or scattered regarding emerging or advanced energy-efficiency and low-carbon technologies that are not yet commercialized. This report consolidates available information on nineteen emerging technologies for the cement industry, with the goal of providing engineers, researchers, investors, cement companies, policy makers, and other interested parties with easy access to a well-structured database of information on these technologies.

  9. Feasibility study of fluxless brazing cemented carbides to steel

    Science.gov (United States)

    Tillmann, W.; Sievers, N.

    2017-03-01

    One of the most important brazing processes is the joints between cemented carbides and steel for the tool industry such as in rotary drill hammers or saw blades. Even though this technique has already been used for several decades, defects in the joint can still occur and lead to quality loss. Mostly, the joining process is facilitated by induction heating and the use of a flux to enhance the wetting of the filler alloy on the surface of the steel and cemented carbide in an ambient atmosphere. However, although the use of flux enables successful joining, it also generates voids within the joint, which reduces the strength of the connection while the chemicals within the flux are toxic and polluting. In this feasibility study, a fluxless brazing process is used to examine the joint between cemented carbides and steel for the first time. For this, ultrasound is applied during induction heating to enable the wetting between the liquid filler metal and the surfaces of the cemented carbide and steel. The ultrasound generates cavitations within the liquid filler metal, which remove the oxides from the surface. Several filler metals such as a silver based alloy Ag449, pure Zn, and an AlSi-alloy were used to reduce the brazing temperature and to lower the thermal residual stresses within the joint. As a result, every filler metal successfully wetted both materials and led to a dense connection. The ultrasound has to be applied carefully to prevent a damage of the cemented carbide. In this regard, it was observed that single grains of the cemented carbide broke out and remained in the joint. This positive result of brazing cemented carbides to steel without a flux but using ultrasound, allows future studies to focus on the shear strength of these joints as well as the behavior of the thermally induced residual stresses.

  10. Grout cement. ; Grout cement to fill ground/grout cement to fill cracks. Chunyuyo cement. ; Jiban chunyuyo cement /hibiware chunyuyo cement

    Energy Technology Data Exchange (ETDEWEB)

    Okaue, H. (Nittetsu Cement Co. Ltd., Hokkaido (Japan))

    1991-09-01

    Ground grout cement is grouted into the ground under high pressure in high water ratio (100 to 1000%) in the form of milk differing from concrete in terms of the water-cement ratio. The grouted milk is governed by characteristics of the cement the milk itself possesses, resulting in variable grouting modes, which are divided in fracture grouting, permeation grouting and boundary grouting. Their applications include cutting off of water in dams, ground reinforcement, prevention of water gushing in tunnel excavation, natural ground reinforcement, improvement of sandy soil and prevention of its collapse, and stabilization of ground for urban civil engineering works such as subway, water supply and sewerage constructions. Grout cement to fill cracks in concrete structures is so grouted into cracks that the slurry fills up contiguous cracks to a certain level and goes upward while pushing out air or water existing in the cracks. The slurry filled into the cracks solidifies and hardens while being absorbed into the concrete, and finally integrates with the concrete. The grout cement is used to rework such concrete structures as dams, tunnels, and bridge bases. 6 figs., 4 tabs.

  11. Remesas a los países andinos: Tendencias, costos e impacto económico

    OpenAIRE

    Andrés Solimano

    2003-01-01

    Da a conocer las tendencias globales y regionales de las remesas en los países andinos, las características de los mercados internacionales, costos del envío de remesas y las políticas para reducir costos de envío de remesas.

  12. 21 CFR 888.4200 - Cement dispenser.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cement dispenser. 888.4200 Section 888.4200 Food... DEVICES ORTHOPEDIC DEVICES Surgical Devices § 888.4200 Cement dispenser. (a) Identification. A cement dispenser is a nonpowered syringe-like device intended for use in placing bone cement (§ 888.3027)...

  13. Propriedades mecânicas de compósitos cimentícios produzidos com lodo de estação de tratamento de efluentes da indústria de batata pré-fritas Mechanical properties of cement composites produced with sludge from the pre-fried potato industry's effluent treatment station

    Directory of Open Access Journals (Sweden)

    Domingos Sávio de Resende

    2012-06-01

    Full Text Available O grande volume de resíduos sólidos industriais gerados pela indústria de batatas pré-fritas e o alto custo do seu manejo estimulam pesquisas em busca de soluções mais adequadas para a sua destinação final. Esse trabalho caracterizou o resíduo sólido (lodo de Estação de Tratamento de Efluentes (ETE de indústria de batatas. O lodo foi processado através de secagem, desidratação, moagem e peneiramento. Para a caracterização do lodo foram utilizadas técnicas de granulometria a laser, microscopia eletrônica de varredura (MEV com espectrômetro de raios X dispersivo em energia (EDS, difração de raio X, análise térmica diferencial (DTA, termogravimétrica (TGA e perda ao fogo. Após a caracterização, o lodo foi utilizado para a confecção de compósitos cimentícios, em substituição parcial do cimento, em massa equivalente para substituição do mesmo volume, determinado pelas massas específicas de ambos materiais, nas porcentagens de 3, 5, 7 e 10%. Os compósitos foram ensaiados para a obtenção da resistência à compressão e do módulo de elasticidade dinâmico. A utilização do lodo de ETE como pozolana foi descartada, tendo-se como base o resultado do ensaio de perda ao fogo. Nos ensaios mecânicos realizados, nota-se que a adição de lodo, em substituição parcial ao cimento, impactou, negativamente, de forma mais relevante a resistência à compressão. Tais ensaios foram considerados satisfatórios para os compósitos com substituição do cimento por 3% e 5% de lodo.The large volume of industrial solid waste generated by the pre-fried potato industry and the high cost of its management encouraged researchers to find solutions best suited to its final destination. This study characterized the solid residue (sludge from the effluents pre-fried potatoes industry's treatment station. The sludge was processed by drying, grinding and sieving. Laser particle size, scanning electron microscopy (SEM with X

  14. Optimization of fly ash as sand replacement materials (SRM) in cement composites containing coconut fiber

    Science.gov (United States)

    Nadzri, N. I. M.; Jamaludin, S. B.; Mazlee, M. N.; Jamal, Z. A. Z.

    2016-07-01

    The need of utilizing industrial and agricultural wastes is very important to maintain sustainability. These wastes are often incorporated with cement composites to improve performances in term of physical and mechanical properties. This study presents the results of the investigation of the response of cement composites containing coconut fiber as reinforcement and fly ash use as substitution of sand at different hardening days. Hardening periods of time (7, 14 and 28 days) were selected to study the properties of cement composites. Optimization result showed that 20 wt. % of fly ash (FA) is a suitable material for sand replacement (SRM). Meanwhile 14 days of hardening period gave highest compressive strength (70.12 MPa) from the cement composite containing 9 wt. % of coconut fiber and fly ash. This strength was comparable with the cement without coconut fiber (74.19 MPa) after 28 days of curing.

  15. Novorossiysk agglomeration landscapes and cement production: geochemical impact assessment

    Science.gov (United States)

    Alekseenko, A. V.; Pashkevich, M. A.

    2016-09-01

    The article deals with assessing the environmental impact of marl mining and cement production in Novorossiysk city (Krasnodar krai, Russia). The existing methods of studying the environmental effects caused by the cement industry have been reviewed. Soil and aquatic vegetation sampling has been carried out and the gross concentration of metals in the samples has been defined. The research has been conducted in the certified and accredited laboratory using emission spectral analysis. The external control has been carried out via X-ray fluorescence analysis. Based on the collected data, main chemical pollutants in soil cover and water area near the cement plant have been identified. The contaminants released by urban enterprises and motor vehicle emissions, as well as fugitive dust from dumps and the cement factory, lead to multi-element lithogeochemical anomaly at geochemical barriers in soils. Accumulation of pollutants in soil depends on the type of land use and the area relief. The most contaminated aquatic landscapes have been identified in the inner bay. According to this information, the technical proposals can be prepared for environmental safety management in strongly polluted city areas, as well as for the reclamation design in the areas currently experiencing the negative impact of cement production.

  16. Cements containing by-product gypsum

    Energy Technology Data Exchange (ETDEWEB)

    Bensted, J. [University of Greenwich, London (United Kingdom). School of Biological and Chemical Sciences

    1995-12-31

    Chemical by-product gypsum can readily replace natural gypsum in Portland cements and in blended cements like Portland pfa cement and Portland blast furnace cement without technical detriment in many instances. Indeed, sometimes the technical performance of the cement can be enhanced. The hydration chemistry is often changed, in that where there is at least some retardation of setting, more AFT phase (ettringite) is formed during early hydration at the expense of calcium silicate hydrates. By-product gypsum can also replace natural gypsum in speciality products like calcium aluminate cement-Portland cement mixes for producing quick setting cements and in calcium sulphoaluminate-type expansive cements. However, by-products gypsum have proved to be less successful for utilization in API Classes of oilwell cements, because of the greater difficulty in obtaining batch-to-batch consistency in properties like thickening time and slurry rheology. 11 refs., 3 figs., 5 tabs.

  17. Assessment of non-destructive testing of well casing,, cement and cement bond in high temperature wells

    Energy Technology Data Exchange (ETDEWEB)

    Knutson, C K; Boardman, C R

    1979-01-01

    Because of the difficulty in bringing geothermal well blowouts under control, any indication of a casing/cement problem should be expeditiously evaluated and solved. There are currently no high temperature cement bond and casing integrity logging systems for geothermal wells with maximum temperatures in excess of 500/sup 0/F. The market is currently insufficient to warrannt the private investment necessary to develop tools and cables capable of withstanding high temperatures. It is concluded that a DOE-funded development program is required to assure that diagnostic tools are available in the interim until geothermal resource development activities are of sufficient magnitude to support developmental work on high temperature casing/cement logging capabilities by industry. This program should be similar to and complement the current DOE program for development of reservoir evaluation logging capabilities for hot wells. The appendices contain annotated bibliographies on the following: high temperature logging in general, cement integrity testing, cosing integrity testing, casing and cement failures, and special and protective treatment techniques. Also included are composite listing of references in alphabetical order by senior author.

  18. Assessment of radioactivity and radon exhalation rate in Egyptian cement.

    Science.gov (United States)

    El-Bahi, S M

    2004-05-01

    The cement industry is considered as one of the basic industries that plays an important role in the national economy of developing countries. Activity concentration of 238U, 232Th, and 40K in local cement types from different Egyptian factories has been measured using a shielded HPGe detector. The average values obtained for 238U, 232Th, and 40K activity concentrations in different types of cement are lower than the corresponding global values reported in UNSCEAR publications. On the basis of the hazard index and the radium equivalent concentration, it can be shown that the natural radioactivity of cement samples is not greater than the values permitted in the established standards in other countries. A solid-state nuclear track detector SSNTD (Cr-39) was used to measure the radon concentration as well as exhalation rate for these samples. The effective radium content and the exhalation rate are found to vary from 12.75 to 38.52 Bq kg(-1) and 61.19 to 181.39 Bq m(-2) d(-1), respectively.

  19. Hydration of blended cement pastes containing waste ceramic powder as a function of age

    Science.gov (United States)

    Scheinherrová, Lenka; Trník, Anton; Kulovaná, Tereza; Pavlík, Zbyšek; Rahhal, Viviana; Irassar, Edgardo F.; Černý, Robert

    2016-07-01

    The production of a cement binder generates a high amount of CO2 and has high energy consumption, resulting in a very adverse impact on the environment. Therefore, use of pozzolana active materials in the concrete production leads to a decrease of the consumption of cement binder and costs, especially when some type of industrial waste is used. In this paper, the hydration of blended cement pastes containing waste ceramic powder from the Czech Republic and Portland cement produced in Argentina is studied. A cement binder is partially replaced by 8 and 40 mass% of a ceramic powder. These materials are compared with an ordinary cement paste. All mixtures are prepared with a water/cement ratio of 0.5. Thermal characterization of the hydrated blended pastes is carried out in the time period from 2 to 360 days. Simultaneous DSC/TG analysis is performed in the temperature range from 25 °C to 1000 °C in an argon atmosphere. Using this thermal analysis, we identify the temperature, enthalpy and mass changes related to the liberation of physically bound water, calcium-silicate-hydrates gels dehydration, portlandite, vaterite and calcite decomposition and their changes during the curing time. Based on thermogravimetry results, we found out that the portlandite content slightly decreases with time for all blended cement pastes.

  20. Substitution of the clayey mineral component by lignite fly ash in portland cement clinker synthesis

    Directory of Open Access Journals (Sweden)

    Jovanović Nataša

    2006-01-01

    Full Text Available Fly ash from four power plants in Serbia (PP "Morava" - Svilajnac, PP "Kolubara" - Veliki Grijani, PP "Kostolac" - units B1 and B2 - Kostolac and PP "Nikola Tesla" - units A and B - Obrenovac was utilized as the starting raw component for Portland cement clinker synthesis. Limestone and quartz sand from the "Holcim - Serbia, a.d." cement factory were the other two starting raw components. Based on the chemical composition of the raw components and from the projected cement moduli, the amounts of raw components in the raw mixtures were calculated. Six different raw mixtures were prepared - each one consisted of limestone, sand and different fly ash. A raw mixture from the industrial production of the "Holcim - Serbia, a.d." cement factory was used as the reference material. The prepared raw mixtures were sintered in a laboratory furnace at 1400°C. The chemical and mineralogical compositions of the synthesized clinkers were determined. The characteristics of clinkers, based on fly ash, were compared to the characteristics of the industrial Portland cement clinker from the "Holcim - Serbia, a.d." cement factory. The results of the investigation showed that fly ash from power plants in Serbia can be suitable for Portland cement clinker synthesis.

  1. Effects of Particle Size and Cement Replacement of LCD Glass Powder in Concrete

    Directory of Open Access Journals (Sweden)

    Seong Kyum Kim

    2017-01-01

    Full Text Available The high quality liquid crystal display (LCD processing waste glass (LPWG generated from the manufacturing process of Korea’s LCD industries, having the world’s highest technological level and production, was finely ground into particles smaller than cement particles (higher fineness than OPC to verify their applicability and performance as a replacement for cement. For a concrete mix having a W/B ratio of 0.44, cement was replaced with LPWG glass powder (LGP at ratios of 5, 10, 15, and 20% (LGP12 and 5 and 10% (LGP5 according to the particle size to prepare test cylinder specimens, which were tested with respect to air contents, slump in fresh concrete, and compressive strength and splitting tensile strength of hardened concrete. The microstructure of the concrete specimens was analyzed through Scanning Electron Microscopy (SEM, Energy Dispersive X-ray (EDX, and a Mercury Intrusion Porosimetry (MIP. Replacement of cement with LGP for cement could effectively decrease the quantity of cement used due to the excellent performance of LGP. It may positively contribute to the sustainable development of the cement industry as well as waste recycling and environment conservation on a national scale.

  2. Magnesium substitution in brushite cements.

    Science.gov (United States)

    Alkhraisat, Mohammad Hamdan; Cabrejos-Azama, Jatsue; Rodríguez, Carmen Rueda; Jerez, Luis Blanco; Cabarcos, Enrique López

    2013-01-01

    The use of magnesium-doped ceramics has been described to modify brushite cements and improve their biological behavior. However, few studies have analyzed the efficiency of this approach to induce magnesium substitution in brushite crystals. Mg-doped ceramics composed of Mg-substituted β-TCP, stanfieldite and/or farringtonite were reacted with primary monocalcium phosphate (MCP) in the presence of water. The cement setting reaction has resulted in the formation of brushite and newberyite within the cement matrix. Interestingly, the combination of SAED and EDX analyses of single crystal has indicated the occurrence of magnesium substitution within brushite crystals. Moreover, the effect of magnesium ions on the structure, and mechanical and setting properties of the new cements was characterized as well as the release of Ca(2+) and Mg(2+) ions. Further research would enhance the efficiency of the system to incorporate larger amounts of magnesium ions within brushite crystals.

  3. 7th NCB international seminar on cement and building materials. Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-07-01

    Topics covered include: mining and mine environment (including CO{sub 2} mitigation in cement concrete industries), and project engineering and management (in volume 1); productivity enhancement and process optimisation (upgrading/cost reduction, grinding/refractories, process optimisation and control, and maintenance) (in volume 2); plant environment and pollution control (including global climate change) performance of concrete, and Portland and blended cements (in volume 3); special cements and binders, total quality management and energy management (in volume 4); and supplementary papers in volume 5.

  4. An ongoing investigation on modeling the strength properties of water-entrained cement-based materials

    DEFF Research Database (Denmark)

    Esteves, L.P.

    2012-01-01

    Water-entrained cement based materials by superabsorbent polymers is a concept that was introduced in the research agenda about a decade ago. However, a recent application in the production of high performance concrete revealed potential weaknesses when the proportioning of this intelligent...... material is not well performed, raising doubts among both academic and industrial society about the usability of superabsorbent polymers in cement-based materials. This work constitutes the baseline tentatively to be used on modeling the compressive strength of SF-modified water-entrained cement...

  5. Utilization of “Marble Slurry” In Cement Concrete Replacing Fine Agreegate

    Directory of Open Access Journals (Sweden)

    Er: Raj.p.singh kushwah

    2015-01-01

    Full Text Available The wastage of marble industry are responsible for many environmental problems because 70% wastes and only 30% recovery of main product contribute to the maximum wastes which are indestructible. Dumping sites give dirty look. Contaminate top fertile soil cover, along with rivers/water bodies affecting irrigation and drinking water resources and air as well as loss to flora and fauna. The most efficient Solution of marble slurry pollution is utilization in Bulk. The only industry which can consume marble slurry at so large level is only the construction industry. Different properties of marble slurry determined in the laboratory. Sp. gravity 2.61, Fineness modulus was found to be 0.91 and Utilization of marble slurry in Cement Concrete replacing Sand is 30% which shows equal strength as of Control i,e. 1:2:4 Cement Concrete 0% Marble slurry. Marble slurry can be easily utilized in construction industry in preparing Cement Concrete.

  6. The assessment of clinker and cement regenerated from completely recyclable concrete

    OpenAIRE

    De Schepper, Mieke; Vernimmen, Lies; De Belie, Nele; De Buysser, Klaartje; Van Driessche, Isabel

    2011-01-01

    As the construction sector uses 50% of the earth’s raw material and produces 50% of its waste, the development of more durable and sustainable building products is crucial. Nowadays, Construction and Demolition Waste (CDW) is already used as recycled aggregates in low-value concrete applications, since it is mostly inert material. On the other hand, the general trend today for the cement industries is the use of alternative raw materials for the production of cement clinker. From this and the...

  7. Rent sharing to control non-cartel supply in the German cement market

    OpenAIRE

    2016-01-01

    A challenge for many cartels is avoiding a destabilizing increase in non-cartel supply in response to having raised price. In the case of the German cement cartel that operated over 1991-2002, the primary source of non-cartel supply was imports from Eastern European cement manufacturers. Industry sources have claimed that the cartel sought to control imports by sharing rents with intermediaries in order to discourage them from sourcing foreign supply. Specifically, cartel members would all...

  8. Recycling of red muds with the extraction of metals and special additions to cement

    Science.gov (United States)

    Zinoveev, D. V.; Diubanov, V. G.; Shutova, A. V.; Ziniaeva, M. V.

    2015-01-01

    The liquid-phase reduction of iron oxides from red mud is experimentally studied. It is shown that, in addition to a metal, a slag suitable for utilization in the construction industry can be produced as a result of pyrometallurgical processing of red mud. Portland cement is shown to be produced from this slag with mineral additions and a high-aluminate expansion addition to cement.

  9. Calcium Orthophosphate Cements and Concretes

    Directory of Open Access Journals (Sweden)

    Sergey V. Dorozhkin

    2009-03-01

    Full Text Available In early 1980s, researchers discovered self-setting calcium orthophosphate cements, which are a bioactive and biodegradable grafting material in the form of a powder and a liquid. Both phases form after mixing a viscous paste that after being implanted, sets and hardens within the body as either a non-stoichiometric calcium deficient hydroxyapatite (CDHA or brushite, sometimes blended with unreacted particles and other phases. As both CDHA and brushite are remarkably biocompartible and bioresorbable (therefore, in vivo they can be replaced with newly forming bone, calcium orthophosphate cements represent a good correction technique for non-weight-bearing bone fractures or defects and appear to be very promising materials for bone grafting applications. Besides, these cements possess an excellent osteoconductivity, molding capabilities and easy manipulation. Furthermore, reinforced cement formulations are available, which in a certain sense might be described as calcium orthophosphate concretes. The concepts established by calcium orthophosphate cement pioneers in the early 1980s were used as a platform to initiate a new generation of bone substitute materials for commercialization. Since then, advances have been made in the composition, performance and manufacturing; several beneficial formulations have already been introduced as a result. Many other compositions are in experimental stages. In this review, an insight into calcium orthophosphate cements and concretes, as excellent biomaterials suitable for both dental and bone grafting application, has been provided.

  10. THE PREPARATION AND COMPOSITION ANALYSIS OF ALITE-YE'ELIMITE WITH INDUSTRIAL WASTES

    OpenAIRE

    Yueyang Hu; Suhua Ma; Li Weifeng; Shen Xiaodong

    2016-01-01

    Alite-ye'elimite clinker is a high cementing clinker that is prepared by introducing calcium sulfoaluminate, a non-silicate mineral, into cement clinker. The industrial residue was used to produce cement clinker. The relationship of the aluminate modulus (IM) and the mineral composition and mechanics of tricalcium silicate-rich sulfur aluminate cement is reported. The effects of the aluminate modulus on the phase compositions, morphology and compressive strength were investigated. The phase m...

  11. Tendencia de los consumos de alimentos en Colombia

    Directory of Open Access Journals (Sweden)

    Kalmanovitz Salomón

    1980-12-01

    Full Text Available En un tipo de economía como la colombiana, caracterizada por salarios que tienen muy poca ligazón con la productividad social del trabajo, estos son por lo general muy bajos y una parte de ellos, que llega a ser más de la mitad, se dedica a la adquisición de alimentos. Mientras el salario mínimo en Colombia era en enero de 1979 de US$ 3.10 diarios, en Estados Unidos era de US$ 3.75 la hora, al tiempo que la jornada de trabajo acá era un 20% más larga (48 horas a la semana contra 40 , lo que representa una diferencia abismal de 12 veces. Las diferencias de productividad industrial en 1974 eran de sólo 4 veces en términos de valor agregado por trabajador o sea que un capitalista operando en el país estrujaba 3 veces más trabajo sobrante a cada obrero que el correspondiente a un empresario yanki.

  12. Formation, release and control of dioxins in cement kilns.

    Science.gov (United States)

    Karstensen, Kåre Helge

    2008-01-01

    Co-processing of hazardous wastes in cement kilns have for decades been thought to cause increased emissions of PCDD/PCDFs--a perception that has been evaluated in this study. Hundreds of PCDD/PCDF measurements conducted by the cement industry and others in the last few years, on emissions and solid materials, as well as recent test burns with hazardous wastes in developing countries do not support this perception. Newer data has been compared with older literature data and shows in particular that many emission factors have to be reconsidered. Early emission factors for cement kilns co-processing hazardous waste, which are still used in inventories, are shown to be too high compared with actual measurements. Less than 10 years ago it was believed that the cement industry was the main contributor of PCDD/PCDFs to air; data collected in this study indicates however that the industry contributes with less than 1% of total emissions to air. The Stockholm Convention on POPs presently ratified by 144 parties, classifies cement kilns co-processing hazardous waste as a source category having the potential for comparatively high formation and release of PCDD/PCDFs. This classification is based on early investigations from the 1980s and 1990s where kilns co-processing hazardous waste had higher emissions compared to those that did not burn hazardous waste. However, the testing of these kilns was often done under worst case scenario conditions known to favour PCDD/PCDF formation. More than 2000 PCDD/PCDF cement kiln measurements have been evaluated in this study, representing most production technologies and waste feeding scenarios. They generally indicate that most modern cement kilns co-processing waste today can meet an emission level of 0.1ngI-TEQ/m(3), when well managed and operated. In these cases, proper and responsible use of waste including organic hazardous waste to replace parts of the fossil fuel does not seem to increase formation of PCDD/PCDFs. Modern preheater

  13. Metodologías de diseño de pavimentos flexibles: tendencias, alcances y limitaciones

    OpenAIRE

    Hugo Alexander Rondón Quintana; Fredy Alberto Reyes Lizcano

    2007-01-01

    El artículo presenta los tipos de metodologías para el análisis y diseño de estructuras de pavimentos flexibles en el mundo, las tendencias actuales y el avance de herramientas computacionales en la ingeniería de pavimentos. Se discuten los alcances y limitaciones de dichas metodologías y tendencias, haciendo énfasis en el comportamiento de materia-les granulares que conforman capas de base y subbase. Además se realiza una discusión crítica sobre la forma como el método de diseño colomb...

  14. Metodologías de diseño de pavimentos flexibles: tendencias, alcances y limitaciones

    Directory of Open Access Journals (Sweden)

    Hugo Alexander Rondón Quintana

    2007-01-01

    Full Text Available El artículo presenta los tipos de metodologías para el análisis y diseño de estructuras de pavimentos flexibles en el mundo, las tendencias actuales y el avance de herramientas computacionales en la ingeniería de pavimentos. Se discuten los alcances y limitaciones de dichas metodologías y tendencias, haciendo énfasis en el comportamiento de materia-les granulares que conforman capas de base y subbase. Además se realiza una discusión crítica sobre la forma como el método de diseño colombiano evalúa el fenómeno de defor-mación permanente en estructuras de pavimentos flexibles.

  15. Análisis del turismo de salud en Europa. Evolución y tendencias

    OpenAIRE

    2012-01-01

    En este trabajo nos centraremos en el turismo de salud en Europa, su evolución y tendencias. Para ello, por un lado, explicaremos el origen y la evolución del turismo de salud, centrándonos en el turismo de balneario, dado que es una de las tendencias que más ha durado a lo largo del tiempo. En la actualidad las prácticas relacionadas con la salud y el agua las asociamos más a prácticas lúdicas y de ocio que a prácticas medicinales. Sin embargo, el uso de las aguas y termas min...

  16. Tendencias de la contabilidad internacional en el sector público en Colombia

    Directory of Open Access Journals (Sweden)

    Aída Patricia Calvo V.

    2006-01-01

    Full Text Available El presente artículo es parte de una propuesta de investigación con la que se pretenden construir elementos para identifi car, analizar y comprender las principales tendencias de la contabilidad internacional en el sector público; haciendo énfasis en aquellas que en Colombia aparecen como respuesta al contexto global, y partiendo de allí interpretar los procesos de normalización y armonización contable. La perspectiva de la investigación está en generar nuevas interpretaciones de las organizaciones socio-económicas, sus dimensiones y actuaciones. Es allí donde resulta válido el acercamiento a las tendencias de los sistemas de información contable.

  17. Modelos y tendencias de la formación docente universitaria

    Directory of Open Access Journals (Sweden)

    Pilar Aramburuzabala

    2013-01-01

    Full Text Available El presente artículo explicita los modelos teóricos y las tendencias que subyacen a los programas de Formación del Profesorado Universitario (FPU y propone definir planteamientos sistémicos del ámbito supra - universitario, con el fin de contribuir a profesionalizar el rol docente y mejorar la calidad de la enseñanza universitaria. Este trabajo tiene como objetivos describir los modelos, trazar las tendencias de la FPU y proponer mejoras tras la implantación del plan Bolonia. Para ello, profundiza en la literatura y aborda nuevas perspectivas desde la reflexión crítica.

  18. La formación en democracia: nueva tendencia en los organismos electorales latinoamericanos

    Directory of Open Access Journals (Sweden)

    Ileana Aguilar Olivares

    2012-07-01

    Full Text Available : Este artículo analiza, de manera comparada, la tendencia latinoamericana del último lustro a crear institutos, centros o escuelas de formación democrática dentro de la estructura de los organismos electorales. Se describen dichos institutos, sus funciones y públicos meta, identificando los rasgos comunes. Asimismo, se describen las principales líneas de trabajo en capacitación y en gestión del conocimiento por parte de esos institutos. También se comparan sus estructuras administrativas y las previsiones de financiamiento para sus actividades. Finalmente, se hace un recuento de las tendencias generales de diseño.

  19. 21 CFR 888.3027 - Polymethylmethacrylate (PMMA) bone cement.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Polymethylmethacrylate (PMMA) bone cement. 888... Polymethylmethacrylate (PMMA) bone cement. (a) Identification. Polymethylmethacrylate (PMMA) bone cement is a device...: Polymethylmethacrylate (PMMA) Bone Cement.”...

  20. Cementation of Loose Sand Particles based on Bio-cement

    Institute of Scientific and Technical Information of China (English)

    RONG Hui; QIAN Chunxiang

    2014-01-01

    Loose sand particles could be cemented to sandstone by bio-cement (microbial induced magnesium carbonate). The bio-sandstone was firstly prepared, and then the compressive strength and the porosity of the sandstone cemented by microbial induced magnesium carbonate were tested to characterize the cementation effectiveness. In addition, the formed mineral composition and the microstructure of bio-sandstone were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The experimental results show that the feasibility of binding loose sand particles using microbial induced magnesium carbonate precipitation is available and the acquired compressive strength of bio-sandstone can be excellent at certain ages. Moreover, the compressive strength and the porosity could be improved with the increase of microbial induced magnesium carbonate content. XRD results indicate that the morphology of magnesium carbonate induced by microbe appears as needles and SEM results show that the cementation of loose sand particles to sandstone mainly relies on the microbial induced formation of magnesium carbonate precipitation around individual particles and at particle-particle contacts.

  1. Nuevas tendencias en la investigación en salud mental.

    Directory of Open Access Journals (Sweden)

    GHMM ten Horn

    2004-01-01

    Full Text Available Debido a que el modelo de atención en salud mental ha cambiado desde una orientación hospitalaria a una comunitaria, la orientación de los investigadores ha cambiado también. La nueva tendencia es investigar prestando mayor atención a la prevención, la cronicidad, la colaboración entre salud mental y atención primaria, y el entorno de los sujetos en estudio.

  2. Spent FCC catalyst for improving early strength Portland cement

    OpenAIRE

    Borrachero Rosado, María Victoria; Monzó Balbuena, José Mª; Paya Bernabeu, Jorge Juan; Vunda, Christian; VELÁZQUEZ RODRÍGUEZ, SERGIO; Soriano Martinez, Lourdes

    2014-01-01

    Spent fluid catalytic cracking (FCC) catalyst from the petrol industry has proven to be a very active pozzolanic material. This behavior leads to an additional increase in the strength of the mortar that contains this catalyst. Pozzolanic effects tend to be considered for periods above three days, whereas in shorter times, the influence of pozzolan is usually negligible. The reactivity of FCC is so high, however, that both pozzolanic effects and acceleration of cement hydration are evident in...

  3. THE INFLUENCE OF THE COMPLEX CHEMICAL ADDITIVE CONTAINING THE STRUCTURED CARBON NANOMATERIAL ON PROPERTIES OF CEMENT

    Directory of Open Access Journals (Sweden)

    O. Yu. Sheyda

    2015-01-01

    Full Text Available The paper presents results of investigations on influence of domestic complex chemical additive containing structured carbon nanomaterial and characterized by a combination effect (curing acceleration and plasticizing on cement and cement stone properties. The purpose of the investigations, on the one hand, has been to confirm efficacy of УКД-1additive from the perspective for increasing the rate of gain, strength growth of cement concrete and additive influence on setting time with the purpose to preserve molding properties of concrete mixes in time, and on the other hand, that is to assess “mechanism” of the УКД-1 additive action in the cement concrete. The research results have revealed regularities in changes due to the additive of water requirements and time period of the cement setting. The reqularities are considered as a pre-requisite for relevant changes in molding properties of the concrete mixes. The paper also experimentally substantiates the possibility to decrease temperature of cement concrete heating with the УДК-1 additive. It has been done with the purpose to save energy resources under production conditions. In addition to this the paper proves the efficiency of the additive which is expressed in strength increase of cement stone up to 20–40 % in the rated age (28 days that is considered as a basis for strength growth of cement concrete. The paper confirms a hypothesis on physical nature of this phenomenon because the X-ray phase analysis method has shown that there are no changes in morphology of portland cement hydration products under the action of the additive agent containing a structured carbon nanomaterial. Results of theoretical and experimental investigations on УКД-1 additive efficiency have been proved by industrial approbation while fabricating precast concrete products and construction of monolithic structures under plant industrial conditions (Minsk, SS “Stroyprogress” JSC MAPID and on

  4. Organización y tendencias del conocimiento de enfermería en Chile

    Directory of Open Access Journals (Sweden)

    Sara Mendoza Parra

    2004-04-01

    Full Text Available Estudio cuantitativo, descriptivo y retrospectivo que exploró la organización del conocimiento de la Enfermería Chilena y sus tendencias. El universo estuvo constituido por reportes científicos publicados en las revistas de enfermería chilenas entre 1965 y 2003 (N=214. Se utilizó pauta basada en la CIPE, criterios de Nogueira e indicaciones de cienciometría. El análisis con medidas estadísticas de tendencia central fueron manejadas con SPSS. Algunos resultados fueron: el sujeto de estudio más frecuente fue el profesional de enfermería y la tendencia es enfocarse a las necesidades en salud de las personas adultas y en riesgo de enfermar. Se observa: las publicaciones tienen poco sustento teórico de enfermería, "Ciencia y Enfermería" es la revista que exhibe la mejor calidad científica.

  5. Panorámica de la actual narrativa colombiana: novedades y tendencias

    Directory of Open Access Journals (Sweden)

    Jorge Iván Parra

    2015-11-01

    Full Text Available Este artículo es fundamentalmente una visión panorámica de lo que en los últimos treinta años, ha producido la narrativa (por no decir, la novelística colombiana. La propuesta conduce la mirada hacia cuatro tendencias: histórica, urbana, de la violencia e intimista. Se entiende que una obra o un autor, eventualmente pueden, según sus características, acomodarse en varias tendencias a la vez, o que un autor puede ser visto en unas obras en una tendencia y en algunas obras en otra. Dado que este texto obedece a una apuesta personal producto de la relación directa lector-obras, prácticamente sin ninguna mediación, se inscribe dentro de lo que Edward Said cataloga como crítica práctica y de ahí el tenor de reseña en muchos de los comentarios.

  6. Seating load parameters impact on dental ceramic reinforcement conferred by cementation with resin-cements.

    LENUS (Irish Health Repository)

    Addison, Owen

    2010-09-01

    Cementation of all-ceramic restorations with resin-cements has been demonstrated to reduce the incidence of fracture in service. The aim was to investigate the influence of loading force and loading duration applied during cementation on the reinforcement conferred by a resin-cement on a leucite reinforced glass-ceramic.

  7. 76 FR 76760 - Gray Portland Cement and Cement Clinker From Japan

    Science.gov (United States)

    2011-12-08

    ... Portland Cement and Cement Clinker From Japan Determination On the basis of the record \\1\\ developed in the... antidumping duty order on gray Portland cement and cement clinker from Japan would be likely to lead to... the Commission are contained in USITC Publication 4281 (December 2011), entitled Gray Portland...

  8. Antibacterial potential of contemporary dental luting cements.

    Science.gov (United States)

    Daugela, Povilas; Oziunas, Rimantas; Zekonis, Gediminas

    2008-01-01

    The aims of this investigation were to evaluate the antibacterial activities of different types of dental luting cements and to compare antibacterial action during and after setting. Agar diffusion testing was used to evaluate the antibacterial properties of seven types of dental luting cements (glass ionomer cements (GICs), resin modified GICs, resin composite, zinc oxide eugenol, zinc oxide non-eugenol, zinc phosphate, zinc polycarboxylate cements) on Streptococcus mutans bacteria. Instantly mixed zinc phosphate cements showed the strongest antibacterial activity in contrast to the non-eugenol, eugenol and resin cements that did not show any antibacterial effects. Non-hardened glass ionomer, resin modified and zinc polycarboxylate cements exhibited moderate antibacterial action. Hardened cements showed weaker antibacterial activities, than those ones applied right after mixing.

  9. Freezing resistance of high iron phoasphoaluminate cement

    Science.gov (United States)

    Zhang, S. X.; Lu, L. C.; Wang, S. D.; Zhao, P. Q.; Gong, C. C.

    2017-03-01

    The influence of freeze-thaw cycle on the mechanical properties of high iron phoasphoaluminate cement was investigated in the present study. The visual examination was conducted to evaluate the surface damage. The deterioration considering the weight loss, modulus loss of relative dynamic elastic and strength loss of mortar were also investigated. The morphology of hydration products were analysed by SEM. Compared with ordinary Portland cement and sulphoaluminate cement, the frost resistance of high iron phosphoraluminate cement is better. Hydration products of high iron phoasphoaluminate cement contain sheet crystals, and a lot of gel form a dense three-dimensional network structure, which results in a lower porosity. Different from ordinary Portland cement, the hydration product of high iron phoasphoaluminate cement does not contain Ca(OH)2, and low alkalinity reduces its osmotic pressure. The lower porosity and osmotic pressure are the two main reasons which causes in the higher frost resistance of high iron phoasphoaluminate cement.

  10. Effectiveness of the Top-Down Nanotechnology in the Production of Ultrafine Cement (~220 nm

    Directory of Open Access Journals (Sweden)

    Byung-Wan Jo

    2014-01-01

    Full Text Available The present investigation is dealing with the communition of the cement particle to the ultrafine level (~220 nm utilizing the bead milling process, which is considered as a top-down nanotechnology. During the grinding of the cement particle, the effect of various parameters such as grinding time (1–6 h and grinding agent (methanol and ethanol on the production of the ultrafine cement has also been investigated. Performance of newly produced ultrafine cement is elucidated by the chemical composition, particle size distribution, and SEM and XRD analyses. Based on the particle size distribution of the newly produced ultrafine cement, it was assessed that the size of the cement particle decreases efficiently with increase in grinding time. Additionally, it is optimized that the bead milling process is able to produce 90% of the cement particle <350 nm and 50% of the cement particle < 220 nm, respectively, after 6.3 h milling without affecting the chemical phases. Production of the ultrafine cement utilizing this method will promote the construction industries towards the development of smart and sustainable construction materials.

  11. Barnacle cement: an etchant for stainless steel 316L?

    Science.gov (United States)

    Sangeetha, R; Kumar, R; Doble, M; Venkatesan, R

    2010-09-01

    Localized corrosion of stainless steel beneath the barnacle-base is an unsolved issue for the marine industry. In this work, we clearly bring out for the first time the role of the barnacle cement in acting as an etchant, preferentially etching the grain boundaries, and initiating the corrosion process in stainless steel 316L. The investigations include structural characterization of the cement and corroded region, and also chemical characterization of the corrosion products generated beneath the barnacle-base. Structural characterization studies using scanning electron microscopy (SEM) reveals the morphological changes in the cement structure across the interface of the base-plate and the substrate, modification of the steel surface by the cement and the corrosion pattern beneath the barnacle-base. Fourier transform infrared spectroscopy (FTIR) of the corrosion products show that they are composed of mainly oxides of iron thereby implying that the corrosion is aerobic in nature. A model for the etching and corrosion mechanism is proposed based on our observations.

  12. 76 FR 24519 - Gray Portland Cement and Cement Clinker From Japan; Institution of a Five-Year Review Concerning...

    Science.gov (United States)

    2011-05-02

    ... COMMISSION Gray Portland Cement and Cement Clinker From Japan; Institution of a Five-Year Review Concerning the Antidumping Duty Order on Gray Portland Cement and Cement Clinker From Japan AGENCY: United States... determine whether revocation of the antidumping duty order on gray portland cement and cement clinker...

  13. 76 FR 50252 - Gray Portland Cement and Cement Clinker From Japan; Scheduling of an Expedited Five-Year Review...

    Science.gov (United States)

    2011-08-12

    ... COMMISSION Gray Portland Cement and Cement Clinker From Japan; Scheduling of an Expedited Five-Year Review Concerning the Antidumping Duty Order on Gray Portland Cement and Cement Clinker From Japan AGENCY: United... cement and cement clinker from Japan would be likely to lead to continuation or recurrence of...

  14. INVESTIGATING EFFECTS OF INTRODUCTION OF CORNCOB ASH INTO PORTLAND CEMENTS CONCRETE: MECHANICAL AND THERMAL PROPERTIES

    Directory of Open Access Journals (Sweden)

    Antonio Price

    2014-01-01

    Full Text Available The purpose of this study was to evaluate the benefits of replacing Ordinary Portland Cement (OPC with Corncob Ash (CCA blended cements. The cement industry contributes considerable amount of Carbon Dioxide (CO2 emissions into the atmosphere. The main contribution of CO2 emissions from cement production results from the process of creating Calcium Oxide (CaO from limestone (CaCO3 commonly known as the calcination process. Blending OPC with a pozzolanic material will assist in the reduction of CO2 emissions due to calcination as well as enhance the quality of OPC. There are various pozzolanic materials such as fly ash, rice husk, silica fume and CCA that could be promising partial replacement for OPC. In this study, CCA will serve as the primary blending agent with OPC. An experiment was performed to designate an appropriate percentage replacement of CCA that would comply with specific standards of cement production. The experimental plan was designed to analyze compressive strength, workability and thermal performance of various CCA blended cements. The data from the experiment indicates that up to 10% CCA replacement could be used in cement production without compromising the structural integrity of OPC. In addition, it was found that the compressive strength and workability of the resulting concrete could be improved when CCA is added to the mixtures. Furthermore, it was shown that the introduction of 10% CCA can lead to significant reduction in thermal conductivity of the mixture.

  15. Influence of various acids on the physico–mechanical properties of pozzolanic cement mortars

    Indian Academy of Sciences (India)

    S Türkel; B Felekoǧlu; S Dulluç

    2007-12-01

    Acidic attack represents a topic of increasing significance, owing to the spread of damages of concrete structures in both urban and industrial areas. Cement type is an important factor affecting performance of cement based materials in an aggressive environment. The goal of this study was to compare the acid resistance of a pozzolanic cement (CEM IV-A/32·5) with Portland cement (CEM I 32·5) that was made from the same clinker. For this purpose, 50 mm mortar cubes were prepared with two different kinds of cement according to TS EN 196-1. After 28 days of hardening, the samples were immersed into four different concentrations of hydrochloric, nitric and sulfuric acid solutions for a period of 120 days. The changes in weight loss and compressive strength values for each acid solution within the test period were recorded. The acid resistance of mortars made from Portland cement was better than the pozzolanic cement incorporated samples after 120 days of acid attack.

  16. Using cement, lignite fly ash and baghouse filter waste for solidification of chromium electroplating treatment sludge

    Directory of Open Access Journals (Sweden)

    Wantawin, C.

    2004-02-01

    Full Text Available The objective of the study is to use baghouse filter waste as a binder mixed with cement and lignite fly ash to solidify sludge from chromium electroplating wastewater treatment. To save cost of solidification, reducing cement in binder and increasing sludge in the cube were focused on. Minimum percent cement in binder of 20 for solidification of chromium sludge was found when controlling lignite fly ash to baghouse filter waste at the ratio of 30:70, sludge to binder ratio of 0.5, water to mixer ratio of 0.3 and curing time of 7 days. Increase of sludge to binder ratio from 0.5 to 0.75 and 1 resulted in increase in the minimum percent cement in binder up to 30 percent in both ratios. With the minimum percent cement in binder, the calculated cement to sludge ratios for samples with sludge to binder ratios of 0.5, 0.75 and 1 were 0.4, 0.4 and 0.3 respectively. Leaching chromium and compressive strength of the samples with these ratios could achieve the solidified waste standard by the Ministry of Industry. For solidification of chromium sludge at sludge to binder ratio of 1, the lowest cost binder ratio of cement to lignite fly ash and baghouse filter waste in this study was 30:21:49. The cost of binder in this ratio was 718 baht per ton dry sludge.

  17. PERFORMANCE OF PULVERIZED SLAG-SUBSTITUTED CEMENT

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    The Portland cement is equivalently substituted by slag micropowders with various specific areas. The workability,activity and acid-corrosion resistance of the slag-substituted cements are investigated,the activation of gypsum is discussed,also the porosity and pore distribution of mortars of the slag micropowders cement are determined by mercury intrusion porosimetry.

  18. 21 CFR 872.3275 - Dental cement.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Dental cement. 872.3275 Section 872.3275 Food and... DENTAL DEVICES Prosthetic Devices § 872.3275 Dental cement. (a) Zinc oxide-eugenol—(1) Identification... filling or as a base cement to affix a temporary tooth filling, to affix dental devices such as crowns...

  19. Cementation in adhesive dentistry: the weakest link

    NARCIS (Netherlands)

    Jongsma, L.A.

    2012-01-01

    Het succesvol bevestigen van tandrestauraties is een belangrijke en veeleisende procedure. Met behulp van cement wordt het restauratiemateriaal aan de tandstructuur verbonden. Op die manier worden twee hechtvlakken gecreëerd: het raakvlak tussen tand en cement, en het raakvlak tussen cement en resta

  20. Magnetic properties of the lichen Pseudevernia furfuracea transplanted near a cement plant in NE Italy

    Science.gov (United States)

    Winkler, Aldo; Kodnik, Danijela; Candotto Carniel, Fabio; Tretiach, Mauro

    2015-04-01

    The magnetic properties of transplanted samples of the epiphytic lichen Pseudevernia furfuracea (L.) Zopf var. furfuracea have been analyzed in the framework of a biomonitoring study in NE Italy focused on a middle-sized cement plant (clinker production: 556,000 ton year-1 in 2012). The lichen transplants were exposed for 2 months in 40 sites distributed all around the cement plant: 37 sites were located at the knots of a 700 m step grid covering agricultural, forest and urban areas and a large industrial zone, and 3 sites were located in the nearby urban centers. The elemental analysis of the exposed samples revealed a limited impact of the cement plant on the territory, while that of the industrial zone, located in the SW corner of the study area, seemed to be generally stronger. The magnetic properties of the transplanted lichens statistically agree with the elemental concentration dataset, showing that the cement plant has no significant impact on the magnetic properties of the lichens transplanted in the whole area. The samples from the industrial area show the highest values of magnetic susceptibility and of saturation magnetization and saturation remanent magnetization, in coherence with the spatial distribution of the elemental concentration values. The magnetic mineralogy is reasonably uniform throughout the whole set of samples, and is dominated by magnetite-like minerals. The magnetic mineralogy of the sample nearest to the cement plant is not magnetically distinguishable from that of the other lichen samples and does not seem to be linked to the magnetic properties of the cement therein produced. The full agreement between the magnetic and elemental datasets underlines a modest environmental impact of the cement plant, with respect to the other industrial activities in the same area.

  1. Technical Difficulties of Environmental Protection Acceptance for Cement Projects in Electronic Components Manufacturing Industry%电子元件行业环保验收监测技术难点研究

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    This paper discussed the technical difficulties of environmental protection for the acceptance and monitoring of e-lectronic components manufacturing industry based on the practical experience and regulatory requirements in combination with technical guidelines for environmental protection acceptance of completed construction projects and the current situation in elec-tronic components manufacturing industry .In view of the technical difficulties of the process analysis of electronic components in-dustry, the determination of pollution factors, the verification of hazardous waste, and the implementation of the inspection and acceptance standards.This works provide a reference for environmental protection in electronic components manufacturing industry construction projects for check/acceptance completed project.%根据建设项目竣工环境保护验收规范要求及当前电子元件行业的发展情况,结合工作实践,探讨新形势下电子元件行业项目竣工环境保护验收监测工作中的技术难点,针对电子元件行业工艺分析及特征污染因子的确定、危险废物核查、验收监测标准执行等技术难点提出了具体解决建议,为电子元件行业项目竣工环境保护验收监测提供参考。

  2. Mercury enrichment and its effects on atmospheric emissions in cement plants of China

    Science.gov (United States)

    Wang, Fengyang; Wang, Shuxiao; Zhang, Lei; Yang, Hai; Wu, Qingru; Hao, Jiming

    2014-08-01

    The cement industry is one of the most significant anthropogenic sources of atmospheric mercury emissions worldwide. In this study of three typical Chinese cement plants, mercury in kiln flue gas was sampled using the Ontario Hydro Method (OHM), and solid samples were analyzed. Particulate matter recycling, preheating of raw materials, and the use of coal and flue gas desulfurization derived gypsum contributed to emissions of Hg in the air and to accumulation in cement. Over 90% of the mercury input was emitted into the atmosphere. Mercury emission factors were 0.044-0.072 g/t clinker for the test plants. The major species emitted into the atmosphere from cement plants is oxidized mercury, accounting for 61%-91% of the total mercury in flue gas. The results of this study help improve the accuracy of the mercury emission inventory in China and provide useful information for developing mercury controls.

  3. Characterization and utilization of cement kiln dusts (CKDs) as partial replacements of Portland cement

    Science.gov (United States)

    Khanna, Om Shervan

    The characteristics of cement kiln dusts (CKDs) and their effects as partial replacement of Portland Cement (PC) were studied in this research program. The cement industry is currently under pressure to reduce greenhouse gas (GHG) emissions and solid by-products in the form of CKDs. The use of CKDs in concrete has the potential to substantially reduce the environmental impact of their disposal and create significant cost and energy savings to the cement industry. Studies have shown that CKDs can be used as a partial substitute of PC in a range of 5--15%, by mass. Although the use of CKDs is promising, there is very little understanding of their effects in CKD-PC blends. Previous studies provide variable and often conflicting results. The reasons for the inconsistent results are not obvious due to a lack of material characterization data. The characteristics of a CKD must be well-defined in order to understand its potential impact in concrete. The materials used in this study were two different types of PC (normal and moderate sulfate resistant) and seven CKDs. The CKDs used in this study were selected to provide a representation of those available in North America from the three major types of cement manufacturing processes: wet, long-dry, and preheater/precalciner. The CKDs have a wide range of chemical and physical composition based on different raw material sources and technologies. Two fillers (limestone powder and quartz powder) were also used to compare their effects to that of CKDs at an equivalent replacement of PC. The first objective of this study was to conduct a comprehensive composition analysis of CKDs and compare their characteristics to PC. CKDs are unique materials that must be analyzed differently from PC for accurate chemical and physical analysis. The present study identifies the chemical and physical analytical methods that should be used for CKDs. The study also introduced a method to quantify the relative abundance of the different

  4. A review of binders used in cemented paste tailings for underground and surface disposal practices.

    Science.gov (United States)

    Tariq, Amjad; Yanful, Ernest K

    2013-12-15

    Increased public awareness of environmental issues coupled with increasingly stringent environmental regulations pertaining to the disposal of sulphidic mine waste necessitates the mining industry to adopt more competent and efficient approaches to manage acid rock drainage. Cemented paste tailings (CPT) is an innovative form of amalgamated material currently available to the mining industry in developed countries. It is made usually from mill tailings mingled with a small amount of binder (customarily Portland cement) and water. The high cost associated with production and haulage of ordinary Portland cement and its alleged average performance as a sole binder in the long term (due to vulnerability to internal sulphate attack) have prompted users to appraise less expensive and technically efficient substitutes for mine tailings paste formulations. Generally, these binders include but are not limited to sulphate resistant cements, and/or as a partial replacement for Portland cement by artificial pozzolans, natural pozzolans, calcium sulphate substances and sodium silicates. The approach to designing environmentally efficient CPT is to ensure long-term stability and effective control over environmental contaminants through the use of composite binder systems with enhanced engineering properties to cater for inherit deficiencies in the individual constituents. The alkaline pore solution created by high free calcium rich cement kiln dust (CKD) (byproduct of cement manufacturing) is capable of disintegrating the solid glassy network of artificial pozzolans to produce reactive silicate and aluminate species when attacked by (OH(-)) ions. The augmented pozzolanic reactivity of CKD-slag and CKD-fly ash systems may produce resilient CPT. Since cemented paste comprising mine tailings and binders is a relatively new technology, a review of the binding materials used in such formulations and their performance evaluation in mechanical fill behaviour was considered pertinent in

  5. Chloride adsorption by calcined layered double hydroxides in hardened Portland cement paste

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Seyoon [School of Engineering, Kings College, University of Aberdeen, Aberdeen AB24 3UE (United Kingdom); Moon, Juhyuk, E-mail: juhyuk.moon@stonybrook.edu [Civil Engineering Program, Department of Mechanical Engineering, State University of New York at Stony Brook, New York 11794 (United States); Bae, Sungchul [Department of Civil and Environmental Engineering, University of California, Berkeley, CA 94720 (United States); Duan, Xiaonan [Department of Materials Science and Engineering, Cornell University, Ithaca, NY 14853 (United States); Giannelis, Emmanuel P. [Department of Materials Science and Engineering, Cornell University, Ithaca, NY 14853 (United States); Center for Refining and Petrochemicals, The Research Institute, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Monteiro, Paulo M. [Department of Civil and Environmental Engineering, University of California, Berkeley, CA 94720 (United States)

    2014-06-01

    This study investigated the feasibility of using calcined layered double hydroxides (CLDHs) to prevent chloride-induced deterioration in reinforced concrete. CLDHs not only adsorbed chloride ions in aqueous solution with a memory effect but also had a much higher binding capacity than the original layered double hydroxides (LDHs) in the cement matrix. We investigated this adsorption in hardened cement paste in batch cultures to determine adsorption isotherms. The measured and theoretical binding capacities (153 mg g{sup −1} and 257 mg g{sup −1}, respectively) of the CLDHs were comparable to the theoretical capacity of Friedel's salt (2 mol mol{sup −1} or 121 mg g{sup −1}), which belongs to the LDH family among cementitious phases. We simulated chloride adsorption by CLDHs through the cement matrix using the Fickian model and compared the simulation result to the X-ray fluorescence (XRF) chlorine map. Based on our results, it is proposed that the adsorption process is governed by the chloride transport through the cement matrix; this process differs from that in an aqueous solution. X-ray diffraction (XRD) analysis showed that the CLDH rebuilds the layered structure in a cementitious environment, thereby demonstrating the feasibility of applying CLDHs to the cement and concrete industries. - Highlights: • We examine the adsorption equilibrium and kinetics of CLDH in the hydrated cement. • CLDH capacity to bind chloride ions in the hydrated cement paste is determined. • We model chloride adsorption by CLDH through the cement matrix. • CLDH reforms the layered structure with ion adsorption in the cement matrix.

  6. Spectroscopic and microscopic characterization of portland cement based unleached and leached solidified waste

    Science.gov (United States)

    Salaita, Ghaleb N.; Tate, Philip H.

    1998-05-01

    In this study, portland cement based solidified/stabilized (S/S) waste and a cement-only control were studied before and after leaching. The solidified waste samples were prepared from a mix of organic-containing industrial waste sludge and portland cement. Toxicity characterization leaching procedure (TCLP) was the leaching test employed. The samples were studied using multi-surface analytical techniques including XPS, SIMS, XRD, FE-SEM and EDS. The data obtained from the various techniques show that leaching does not measurably affect the morphology or composition of the solidified waste sample. However, subtle changes in the composition of the cement control sample were observed. While the concentration of the elements observed on the surface of leached and unleached waste samples by XPS are very similar (except for Mg, Na and N), study of the corresponding cement samples exhibit differences in the level of C, Si, S, and Ca. The unleached cement sample shows lower levels of C and Si, but higher levels of O, S, Ca and Mg, indicating that leaching alters the cement sample. EDS analyses of the elemental composition of the bulk of the leached and unleached waste samples are similar, and also are similar for the leached and unleached cement samples, indicating that under the conditions of the TCLP test, leaching has no effect on the bulk. The high level of Ca present on the surface of the solidified waste indicates entrapment of the waste by the cement. The information and results obtained show that the surface analytical techniques used in this work, when combined with environmental wet methods, can provide a more complete picture of the concentration, chemical state and immobility of solidified waste.

  7. Performance of portland limestone cements: Cements designed to be more sustainable that include up to 15% limestone addition

    Science.gov (United States)

    Barrett, Timothy J.

    In 2009, ASTM and AASHTO permitted the use of up to 5% interground limestone in ordinary portland cement (OPC) as a part of a change to ASTM C150/AASHTO M85. When this work was initiated a new proposal was being discussed that would enable up to 15% interground limestone cement to be considered in ASTM C595/AASHTO M234. This work served to provide rapid feedback to the state department of transportation and concrete industry for use in discussions regarding these specifications. Since the time this work was initiated, ASTM C595/AASHTO M234 was passed (2012c) and PLCs are now able to be specified, however they are still not widely used. The proposal for increasing the volume of limestone that would be permitted to be interground in cement is designed to enable more sustainable construction, which may significantly reduce the CO2 that is embodied in the built infrastructure while also extending the life of cement quarries. Research regarding the performance of cements with interground limestone has been conducted by the cement industry since these cements became widely used in Europe over three decades ago, however this work focuses on North American Portland Limestone Cements (PLCs) which are specifically designed to achieve similar performance as the OPCs they replace.This thesis presents a two-phase study in which the potential for application of cements containing limestone was assessed. The first phase of this study utilized a fundamental approach to determine whether cement with up to 15% of interground or blended limestone can be used as a direct substitute to ordinary portland cement. The second phase of the study assessed the concern of early age shrinkage and cracking potential when using PLCs, as these cements are typically ground finer than their OPC counterparts. For the first phase of the study, three commercially produced PLCs were obtained and compared to three commercially produced OPCs made from the same clinker. An additional cement was tested

  8. Estado y tendencia de la Administración de Proyectos en México

    OpenAIRE

    Vega Díaz, José Alberto

    2004-01-01

    El objetivo general de este estudio, es analizar el estado y las tendencias de la Administración de Proyectos en México e identificar el nivel de harmonización que hay entre la teoría y la puesta en práctica dentro de la industria mexicana. Esto ayudará a las partes interesadas a evaluar el estado del uso de la Administración de Proyectos dentro de su propia compañía en una base comparativa, reconocer y discutir las necesidades que tiene la práctica de la Administración d...

  9. Marketing móvil en Cataluña: mapa de actores, contenidos y tendencias

    OpenAIRE

    Scolari,Carlos Alberto; Navarro Güere, Héctor; Pardo, Hugo; García Medina, Irene; Soriano Clemente, Jaume,

    2009-01-01

    El artículo presenta una parte de los resultados de una investigación realizada en 2008 donde se describen y analizan actores, contenidos y tendencias del marketing móvil en Cataluña. El marketing móvil está transformando las formas de comunicación publicitaria, ya que, al tratarse de un medio de comunicación unipersonal, directo e interactivo y gozar de una alta implantación en el mercado, hace que sea un instrumento especialmente atractivo para realizar muchos tipos de acciones ...

  10. ENFOQUE POR COMPETENCIAS Y MERCADO DE TRABAJO. NUEVAS TENDENCIAS PARA LA EDUCACIÓN UNIVERSITARIA

    OpenAIRE

    Luis Muñoz Varela

    2012-01-01

    En este ensayo se realiza un análisis acerca de las principales y nuevas tendencias que hoy caracterizan la organización del mercado de trabajo y la demanda de nuevos perfiles profesionales, en el marco de la globalización económica y de la sociedad de la información y el conocimiento. Se analiza, a tal efecto, la propuesta pedagógica del enfoque por competencias que, desde hace al menos dos décadas, ha sido impulsada y promovida por parte de autoridades de gobierno, las instituciones del me...

  11. El suicidio y su tendencia social en México: 1990-2011

    OpenAIRE

    René Alejandro JIMÉNEZ-ORNELAS; Leticia CARDIEL-TÉLLEZ

    2013-01-01

    En las últimas dos décadas, al igual que en el resto del mundo, las tasas de mortalidad por sui - cidio en México han presentado una constante tendencia al incremento. Esto ha catalogado al suicidio como un problema de salud que debe ser analizado desde un enfoque multidimensional, para así examinar las características socio demográficas de los suicidas que permitan generar medidas preventivas ante dicha situación y, por ende, procurar la disminución de la incidencia de este fenómeno que se e...

  12. Tendencias tecnológicas en Europa. Análisis de los procesos de prospectiva

    OpenAIRE

    Martín Pereda, José Antonio

    2003-01-01

    El Informe «Tendencias tecnológicas en Europa. Análisis de los procesos de prospectiva», que Cotec publica en su Colección Observaciones de Buenas Prácticas en los sistemas de innovación, es el resultado de un trabajo original e innovador que compara los resultados obtenidos en los estudios de prospectiva tecnológica realizados por cinco de los países más avanzados de Europa.

  13. Tendencias en los ingresos hospitalarios y mortalidad por asma en nuestra comunidad

    OpenAIRE

    Aboal Viñas, Jorge

    2014-01-01

    OBJETIVOS: Analizar la tendencia de los ingresos hospitalarios y la mortalidad por asma en la población de nuestra comunidad a lo largo de 15 años. Asimismo, se evaluará la influencia del polen ambiental en los ingresos por asma de nuestra área sanitaria. METODOS: Análisis retrospectivo de los ingresos hospitalarios y de la mortalidad por asma en nuestra comunidad a lo largo de 15 años. El análisis de los ingresos hospitalarios se hará de forma diferenciada para la poblac...

  14. La representación visual del tiempo en el spot publicitario: modelos y tendencias actuales

    OpenAIRE

    Poncet Trevín, Pablo

    2015-01-01

    Este trabajo tiene como finalidad el estudio de los modelos actuales de representación visual del tiempo en el spot publicitario, haciendo especial hincapié en la relación existente entre dicho fenómeno y el conjunto de tendencias relativas al montaje cinematográfico. Su interés radica en el hecho de que extrapolar teorías aplicadas al arte (especialmente al cine) y a la percepción, al campo publicitario. Esto da como resultado una visión general del paralelismo existente entre la evolución ...

  15. Tendencia de I+D+i en Biomecánica aplicada al deporte

    OpenAIRE

    Ferro Sanchez, Amelia

    2012-01-01

    Análisis de la investigación en el ámbito de la Biomecánica aplicada al deporte. La tendencia de los proyectos en I+D+i de la Biomecánica del Deporte ha cambiado notablemente en las dos últimas décadas. Los investigadores han pasado de aplicar la biomecánica al alto rendimiento deportivo a tratar temas transversales, relacionados en muchos casos con la salud, fisiología, rehabilitación, el control motor, la gestión y, entre otros, el diseño de equipamiento e instalaciones.

  16. Desagrarización en México: tendencias actuales y retos hacia el futuro

    OpenAIRE

    Roberto Escalante; Horacio Catalán; Luis Miguel Galindo; Orlando Reyes

    2007-01-01

    El presente artículo tiene por objetivo presentar un análisis del proceso de desagrarización en México, a fin de identificar las tendencias generales y las perspectivas de desagrarización que ha sufrido el país. El proceso de desagrarización para el caso de México no es reciente; sin embargo, se ha acelerado de manera importante durante las tres últimas décadas, asociado a un periodo de estancamiento de la producción agropecuaria y a las políticas públicas que han promovido una mayor especial...

  17. Significados de las medidas de tendencia central : un estudio con alumnos universitarios de carreras de humanidades.

    OpenAIRE

    Sayritupac Gutierrez, Javier

    2013-01-01

    En el presente trabajo de investigación se analiza los significados personales e institucionales de las medidas de tendencia central en un estudio con alumnos de primeros ciclos de las carreras de humanidades de la Pontificia Universidad Católica del Perú. Para realizar este análisis se consideró como marco teórico el Enfoque Ontosemiótico de la Cognición e Instrucción Matemática (EOS), el cual nos brindó las herramientas necesarias para el análisis de nuestro objeto de estu...

  18. Tendencias de la historia regional en Colombia. Problemas y perspectivas recientes

    OpenAIRE

    Renzo Ramírez Bacca

    2011-01-01

    El texto ofrece un balance de los estudios regionales en Colombia. Los elementos de la interpretación que tiene el autor son los siguientes: 1) Una comprensión contextual sobre la institucionalización de la disciplina. 2) Un  análisis sobre las posibilidades  y problematización del concepto Región. 3) Un balance crítico sobre la producción monográfica regional, con énfasis especial en el caso antioqueño. Y, 4) una mirada sobre las tendencias recientes en los estudios regionales a partir de la...

  19. Some durability aspects of hybrid alkaline cements

    Directory of Open Access Journals (Sweden)

    Donatello S.

    2014-04-01

    Full Text Available Blended cements that contain a high content of fly ash and a low content of Portland cement typically suffer from low early strength development and long setting times. Recently, one method of overcoming these problems has been to use an alkali activator to enhance the reactivity of fly ash particles at early ages. Such cements can be grouped under the generic term “hybrid alkaline cements”, where both cement clinker and fly ash, encouraged by the presence of alkalis, are expected to contribute to cementitious gel formation. The work presented here examines some of the durability aspects of high fly ash content hybrid alkaline cement. Specifically, the aspects investigated were: exposure at high temperatures (up to 1000°C, resistance to immersion in aggressive solutions and susceptibility to the alkali aggregate reaction. All tests were repeated with a commercially available sulfate resistant Portland cement for comparison. When exposed to high temperatures, the hybrid alkaline cement showed strikingly different behaviour compared to the control Portland cement, showing fewer micro-cracks and maintaining residual compressive strengths at least equal to original strengths. Beyond 700°C, the hybrid alkaline cement began to sinter, which resulted in shrinkage of around 5% and a 100% increase in residual compressive strengths. No such sintering event was noted in the control Portland cement, which showed a drastic loss in residual compressive strengths upon heating. In immersion tests, the hybrid alkaline cement possessed excellent resistance to sulfate and seawater attack, similar to the control sulfate resistant cement. Both cements were however severely degraded by immersion in 0.1M HCl for 90 days. Both binders complied with the accelerated alkali-aggregate test but when this test was extended, the hybrid alkaline binder showed much greater dimensional stability. Possible reasons for the differences in durability behaviour in both cements

  20. Hydration of ordinary portland cements made from raw mix containing transition element oxides

    Energy Technology Data Exchange (ETDEWEB)

    Kakali, G.; Tsivilis, S.; Tsialtas, A. [National Technical Univ. of Athens (Greece)

    1998-03-01

    The use of industrial wastes, such as waste tires, waste oil, non-ferrous metal slag, or waste molding sand, as alternative raw materials and fuel in cement plants has been established from an environmental and recycling point of view and is expected to increase in the future. Cement is broadly used, among other hydraulic binders, in the solidification and stabilization of industrial and municipal wastes. This tendency to the use of wastes in the cement industry or the utilization of cement for the handling of wastes has led to the presence of several transition element compounds in the clinker and/or in the hydrated cement. The subject of this paper is the study of the hydration process in cements made from raw mixes containing transition element oxides. The oxides used are ZrO{sub 2}, V{sub 2}O{sub 5}, Ni{sub 2}O{sub 3}, CuO, Co{sub 2}O{sub 3}, MnO, Cr{sub 2}O{sub 3}, TiO{sub 2}, MoO{sub 3}, and ZnO, and their percentage in the raw mixes is 2% w/w. The cement pastes are cured in water for 24 h, 48 h, 7 days and 28 days. Hydration rate and products are studied by means of X-ray diffraction, differential scanning calorimetry, and thermogravimetric analysis. As it is concluded, the added oxides provoke, in general, a retardation of the hydration reactions. The effect is stronger during the first 2 days and becomes negligible at 28 days. The addition of CuO strongly delays the hydration even after 28 days. Its action is related to the formation of Cu(OH){sub 2} during the first days of hydration.

  1. Marine durability of 15 year old concrete specimens made with ordinary portland, slag, and fly ash cements

    Energy Technology Data Exchange (ETDEWEB)

    Mohammed, T.U.; Yamaji, T.; Hamada, H. [Port and Harbor Research Inst., Ministry of Land, Infrastructure and Transport (Japan); Aoyama, T. [PS Corp. (Japan)

    2001-07-01

    A study was conducted in which the marine durability of ordinary portland cement, slag and fly ash cement was examined using 15 year old plain and reinforced concrete cylindrical specimens. In addition, the performance of these cements was also examined in another study for pre-cracked reinforced concrete prism samples. The process of manufacturing cement emits huge amounts of carbon dioxide into the global atmosphere. Replacing a portion of the cement with by-products from the steel industry and thermal power plants (which are both huge emitters of carbon dioxide) can lower carbon dioxide emissions and also solve the disposal issue of slag and fly ash while increasing the long-term durability of concrete structures. In this study, concrete cylindrical specimens were made of ordinary portland cement, slag and fly ash cements. Water-to-cement ratios were 0.45 and 0.55 and the compressive strength of the concrete, corrosion of the steel bars, and chloride-ion concentrations in the concrete were evaluated. It was shown that, with the exception of fly ash cements, the compressive strength of most cements increased after 15 years of exposure compared to its 28 day strength. Type C slag cement demonstrated the best performance against chloride-ion at the surface of concrete made with slag and fly ash. Voids in the steel-concrete interface make it possible for corrosion pits to develop. The use of seawater as mixing water results in earlier strength development at 28 days and does not cause to the strength of the concrete to regress after 15-years of exposure, but it causes more corrosion of steel bars at a lower cover depth. Corrosion of steel bars is not an issue at deeper cover depths. 15 refs., 18 tabs., 8 figs.

  2. Nuevas Tendencias del Cine Chileno tras la llegada del Cine Digital New Tendencies in Chilean Contemporary Cinema After the Implosion Of Digital Video

    Directory of Open Access Journals (Sweden)

    Carolina Larraín Pulido

    2010-07-01

    Full Text Available La llegada de tecnologías digitales al país en pocos años transforma la escena de producción cinematográfica, no sólo modificando los costos y procesos implicados en la cadena de producción y exhibición cinematográfica, sino también posibilitando la gestación de una escena de producción de largometrajes digitales de bajo costo, que permite el surgimiento de una serie de nuevos realizadores, temáticas, estilos, formas de producción y circuitos de exhibición. El artículo Nuevas Tendencias del cine chileno tras la llegada del cine digital explora e intenta dar cuenta de este fenómeno reciente en el medio chileno, dando cuenta de cómo la inserción de la tecnología digital ha impactado sobre estas nuevas cinematografías, revisando nuevos usos, prácticas, representaciones y tendencias presentes en estas realizaciones.Abstract During the past years, the insertion of digital technologies in Chile has greatly affected the nation's film scenario, not only modifying the chain of film production and exhibition, but also generating a production scene of low-budget digital feature film that has allowed the development of new directors, themes, styles and modes of production and exhibition. The present article analyzes this recent phenomenon in Chilean film industry, revising how the insertion of digital technologies has affected these new forms of cinema in terms of style, production practices, exhibition, purposes and main tendencies.

  3. Use of alternative fuels in cement manufacture. Effect on clinker and cement characteristics and properties

    Directory of Open Access Journals (Sweden)

    Puertas, F.

    2004-06-01

    Full Text Available This paper compares industrial clinker and cement produced using conventional and alternative fuels (animal meal, tyres or a mixture of the two. The results show no relevant differences in terms of mineralogical composition between the clinker manufactured with alternative fuels and the product obtained using conventional fuel. Clinker produced with alternative fuels at any one factory have a very similar or even lower content in heavy metals than the product manufactured with conventional fuel in the same plant (with the sole exception of Zn when the alternative fuel used is shredded tyres. Mineralogical and morphological analyses reveal no significant differences between the two types of products that can be attributed to the type of fuel used in their manufacture. All six types of cement studied are compliant with the existing legislation as regards both physical and chemical properties. Cement compressive strength is found to be to legal standards regardless of the type of fuel used. Finally, the rheological properties of the cement paste are observed to be unaffected by the type of fuel.

    Se han estudiado clínkeres y cementos obtenidos en procesos industriales que han utilizado combustibles convencionales y combustibles alternativos (harinas cárnicas, neumáticos usados y mezclas de ambos. Los resultados obtenidos han demostrado que los clínkeres fabricados con los combustibles alternativos no presentan diferencias significativas en la composición mineralógica respecto a los obtenidos con combustibles convencionales. Los contenidos de metales pesados en los clínkeres procedentes de la misma fábrica (a excepción de los contenidos en Zn en aquéllos que utilizan neumáticos son muy similares o incluso inferiores a los fabricados con combustibles convencionales. Los análisis mineralógico y morfológico de los clínkeres no evidencian diferencias asignables al tipo de combustible utilizado. Todos los cementos estudiados cumplen

  4. Experimental study on improving cement quality with oxygen- enriched combustion technology

    Science.gov (United States)

    Liu, Y. Q.; Zhang, A. M.; Qing, S.; Li, F. S.; Yang, S. P.; Yang, Z. F.

    2015-12-01

    With the intensification of the global energy crisis, the production cost of enterprises is continuously increasing because of the rising fuel prices and high requirements for environmental protection. As result, energy savings and environmental protection are vital considerations for a variety of enterprises. As a practical energy-saving technology, oxygen- enriched combustion has played a major role in energy saving and emissions reduction as its application in industrial furnaces has been popularized in recent years. This experiment was conducted in a cement rotary kiln with a capacity of 4000 t/d in a factory in China. Based on measured data in the oxygen-enriched combustion experiment, we determined the patterns of variation in the main parameters of the cement rotary kiln under oxygen-enriched production conditions. The results provide important theoretical and practical base for the cement building materials industry in energy saving and emissions reduction.

  5. Numerical study of co-firing pulverized coal and biomass inside a cement calciner.

    Science.gov (United States)

    Mikulčić, Hrvoje; von Berg, Eberhard; Vujanović, Milan; Duić, Neven

    2014-07-01

    The use of waste wood biomass as fuel is increasingly gaining significance in the cement industry. The combustion of biomass and particularly co-firing of biomass and coal in existing pulverized-fuel burners still faces significant challenges. One possibility for the ex ante control and investigation of the co-firing process are computational fluid dynamics (CFD) simulations. The purpose of this paper is to present a numerical analysis of co-firing pulverized coal and biomass in a cement calciner. Numerical models of pulverized coal and biomass combustion were developed and implemented into a commercial CFD code FIRE, which was then used for the analysis. Three-dimensional geometry of a real industrial cement calciner was used for the analysis. Three different co-firing cases were analysed. The results obtained from this study can be used for assessing different co-firing cases, and for improving the understanding of the co-firing process inside the calculated calciner.

  6. Lime kiln dust as a potential raw material in portland cement manufacturing

    Science.gov (United States)

    Miller, M. Michael; Callaghan, Robert M.

    2004-01-01

    In the United States, the manufacture of portland cement involves burning in a rotary kiln a finely ground proportional mix of raw materials. The raw material mix provides the required chemical combination of calcium, silicon, aluminum, iron, and small amounts of other ingredients. The majority of calcium is supplied in the form of calcium carbonate usually from limestone. Other sources including waste materials or byproducts from other industries can be used to supply calcium (or lime, CaO), provided they have sufficiently high CaO content, have low magnesia content (less than 5 percent), and are competitive with limestone in terms of cost and adequacy of supply. In the United States, the lime industry produces large amounts of lime kiln dust (LKD), which is collected by dust control systems. This LKD may be a supplemental source of calcium for cement plants, if the lime and cement plants are located near enough to each other to make the arrangement economical.

  7. Tendencias de la Educación universitaria en el siglo XXI

    Directory of Open Access Journals (Sweden)

    Ortega Castro, Vicente

    2002-09-01

    Full Text Available Not available

    El cambio de milenio ha propiciado muchos informes, libros y conferencias sobre la situación de las Universidades y los posibles cambios que se avecinaban como consecuencia de las tendencias de cambios en la sociedad, entre los que se encuentran el predominio del conocimiento, laglobalización y la influencia de nuevas tecnologías aplicadas al ámbito de la educación. Para la sociedad europea, en la que España está inmersa política, social y económicamente, es especialmente relevante la expectativa que está despertando la Declaración de Bolonia. Pues bien, tomando este documento como referencia principal, este artículo examina las funciones permanentes de la Universidad: creación de conocimientos, formación de profesionales, servicio a la sociedad y otros, teniendo en cuenta la importancia de la calidad, de la internacionalización, de la competitividad, de la movilidad, de la complejidad, de las nuevas demandas, de los nuevos esquemas de financiación y otros factores que hacen necesario que las Universidades comprendan las nuevas tendencia y hagan un esfuerzo, no solo de adaptación, sino de anticipación.

  8. Las inteligencias y la evaluación: Interrogantes y tendencias actuales

    Directory of Open Access Journals (Sweden)

    Renata Frank de Verthelyi

    2016-02-01

    Full Text Available Los últimos 50 años han sido testigo de múltiples aportes teóricos y fuertes contro-versias respecto de la estructura, naturaleza, y rasgos básicos del concepto de inteligencia. También han dado lugar a la aparición de nuevas técnicas de evaluación cognitiva basadas en los aportes de estas teorías. En un mercado competitivo, que tiende a la globalización, se observan actualmente dos tendencias disímiles: la actualización y ampliación de los tests tradicionales vs. el énfasis en la integración intertest, jerarquizando sub-tests pertenecientes a pruebas diversas. A su vez, en respuesta a la creciente demanda de evaluación multicultural, también predominan dos tendencias: la traducción y adaptación de los tests existentes, vs. la creación de nuevas técnicas de índole no-verbal. Se incluyen algunas sugerencias para la integración clínica de estos aportes en la práctica del quehacer profesional. 

  9. Comparison of Strength for Concrete with GGBS and Cement Using Accelerated Curing Method

    Directory of Open Access Journals (Sweden)

    K. Shyamala

    2016-10-01

    Full Text Available Ground granulated blast-furnace slag ( GGBS is the granular material formed iron ore is molted. blast furnace slag is by-product of steel manufacture which is sometimes used as a substitute for Portland cement. In steel industry when iron ore is molted, then in the molted state all the impurities come at its surface which are removed called slag. It consists mainly of the silicates and alumino silicates of calcium, which are formed in the blast furnace in molten form simultaneously with the metallic iron. Blast furnace slag is blended with Portland cement clinker to form portland blast furnace slag cement. GGBS is used to make durable concrete structures in combination with ordinary Portland cement and/or other pozzolanic materials. GGBFS has been widely used in Europe, and increasingly in the United States and in Asia (particularly in Japan and Singapore for its superiority in concrete durability, extending the lifespan of buildings from fifty years to a hundred years. This project presents the feasibility of the usage of GGBS as hundred percent substitutes for Ordinary portland cement in concrete. Design mix for M20 and M30 has been calculated using IS 10262-2009 for both accelrated curing in warm water and accelrated curing in boiling water method. Tests were conducted on cubes to study the strength of concrete by using GGBS and Ordinary portland cement

  10. Integrated Environmental Quality Assessments of Surface Water around Obajana Cement Production Area

    Directory of Open Access Journals (Sweden)

    E.G. Ameh

    2014-04-01

    Full Text Available Due to industrialization, there is enormous amount of heavy metals been released from anthropogenic sources into the environment. Heavy metals are considered as one of the main sources of environmental pollution since they have significant effect on the ecological quality and water in particular. These pollutants are hazardous to consumers of water that have significant quantity of these heavy metals. The population most exposed to cement polluted water includes workers in cement factories, families of workers living in Staff houses of factories like in Obajana and other neighborhood habitations. The Obajana cement factory consists of cement kilns/coolers with clinkers. The kilns are equipped with pre-heaters and Electro-Static Precipitators (ESP. The facility has raw mills, crushing operations, cement mills that are potential source of pollutants into the water bodies. Storage silos, conveyors, vehicular travel, and other unquantified fugitive source of water contamination exist in the factory. Monitoring the contamination of water with respect to heavy metals is of interest due to their influence on humans, animals and to some extent plants. A good approach to estimate how much of the water is impacted is by using the heavy metal pollution index and metal index for metal concentrations above the control points in water bodies around Obajana cement.

  11. AIR POLLUTION CONTROL THROUGH KILN RECYCLING BY-PASS DUST IN A CEMENT FACTORY

    Directory of Open Access Journals (Sweden)

    F. Mohsenzadeh, J. Nouri, A. Ranjbar, M. Mohammadian Fazli, A. A. Babaie

    2006-01-01

    Full Text Available Air pollution is a major problem in the industrial areas. Cement dust is one of the important environmental pollutants. In this study the possibility of dust recycling especially kiln dust which has significant importance regarding air pollution in the cement plant, was examined. Tehran cement factory is one of the most important Iranian factories which is located in Tehran. This factory produces high volume of pollutants that are released to in environment. The possibility of reusing of kiln by pass returned dust has been examined in this factory. Different percentages of kiln by-pass dust of this factory were added to products and outcomes of its presence in parameters such as chemical compound, granulation, primary and final catch time, volume expansion, consumed water and resistance of mortar were surveyed. The result indicated that by adding the amounts of 3-8 dust the mortar resistance increase, but adding more than 15%, the mortar resistance has been decreased. Survey in consumed water proved that adding dust to cement, the trend for consuming water is decreased. After dust addition dust, primary and final catch time were compared in different samples and data which showed decrease in dust added samples. Cements with dust added showed increase in auto clave expansion. Overally, results proved that, the best percentage rate of dust addition to the cement was 15%.

  12. Applied technique of the cemented fill with fly ash and fine-sands

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Traditional stabilization of backfilling material is done by using Portland cement. However, the high price of cement forced mining engineers to seek cheaper binding materials. Fly ash, which is the industrial waste from thermal power plant, possess the potential activity of jellification, and can be used in cemented fill as a partial substitute for cement to reduce the fill cost. Tests were done during the past few years in Xinqiao Pyrite Mine and Phoenix Copper Mine to determine the technology parameters and the suitable content of fly ash. Specimens with different cement/fly/ash tailings (sands) ratios were tested to obtain the strength values of the fill mass based on the analyses of both the chemical composition and physical and mechanical properties of fly ash. The compressive strength of specimens with a ratio of 1: 2: 8 (cement to fly ash to tailings)can reach 2 MPa after 90 d curing, totally meeting the requirement of artificial pillar and reducing the fill cost by 20%-30%.

  13. DSC and TG Analysis of a Blended Binder Based on Waste Ceramic Powder and Portland Cement

    Science.gov (United States)

    Pavlík, Zbyšek; Trník, Anton; Kulovaná, Tereza; Scheinherrová, Lenka; Rahhal, Viviana; Irassar, Edgardo; Černý, Robert

    2016-03-01

    Cement industry belongs to the business sectors characteristic by high energy consumption and high {CO}2 generation. Therefore, any replacement of cement in concrete by waste materials can lead to immediate environmental benefits. In this paper, a possible use of waste ceramic powder in blended binders is studied. At first, the chemical composition of Portland cement and ceramic powder is analyzed using the X-ray fluorescence method. Then, thermal and mechanical characterization of hydrated blended binders containing up to 24 % ceramic is carried out within the time period of 2 days to 28 days. The differential scanning calorimetry and thermogravimetry measurements are performed in the temperature range of 25°C to 1000°C in an argon atmosphere. The measurement of compressive strength is done according to the European standards for cement mortars. The thermal analysis results in the identification of temperature and quantification of enthalpy and mass changes related to the liberation of physically bound water, calcium-silicate-hydrates dehydration and portlandite, vaterite and calcite decomposition. The portlandite content is found to decrease with time for all blends which provides the evidence of the pozzolanic activity of ceramic powder even within the limited monitoring time of 28 days. Taking into account the favorable results obtained in the measurement of compressive strength, it can be concluded that the applied waste ceramic powder can be successfully used as a supplementary cementing material to Portland cement in an amount of up to 24 mass%.

  14. A Twofold Comparison between Dual Cure Resin Modified Cement and Glass Ionomer Cement for Orthodontic Band Cementation

    Science.gov (United States)

    Attar, Hanaa El; Elhiny, Omnia; Salem, Ghada; Abdelrahman, Ahmed; Attia, Mazen

    2016-01-01

    AIM: To test the solubility of dual cure resin modified resin cement in a food simulating solution and the shear bond strength compared to conventional Glass ionomer cement. MATERIALS AND METHOD: The materials tested were self-adhesive dual cure resin modified cement and Glass Ionomer (GIC). Twenty Teflon moulds were divided into two groups of tens. The first group was injected and packed with the modified resin cement, the second group was packed with GIC. To test the solubility, each mould was weighed before and after being placed in an analytical reagent for 30 days. The solubility was measured as the difference between the initial and final drying mass. To measure the Shear bond strength, 20 freshly extracted wisdom teeth were equally divided into two groups and embedded in self-cure acrylic resin. Four mm sections of stainless steel bands were cemented to the exposed buccal surfaces of teeth under a constant load of 500 g. Shear bond strength was measured using a computer controlled materials testing machine and the load required to deband the samples was recorded in Newtons. RESULTS: GIC showed significantly higher mean weight loss and an insignificant lower Shear bond strength, compared to dual cure resin Cement. CONCLUSION: It was found that dual cure resin modified cement was less soluble than glass ionomer cement and of comparable bond strength rendering it more useful clinically for orthodontic band cementation. PMID:28028417

  15. Influence of the temperature on the cement disintegration in cement-retained implant restorations.

    Science.gov (United States)

    Linkevicius, Tomas; Vindasiute, Egle; Puisys, Algirdas; Linkeviciene, Laura; Svediene, Olga

    2012-01-01

    The aim of this study was to estimate the average disintegration temperature of three dental cements used for the cementation of the implant-supported prostheses. One hundred and twenty metal frameworks were fabricated and cemented on the prosthetic abutments with different dental cements. After heat treatment in the dental furnace, the samples were set for the separation to test the integration of the cement. Results have shown that resin-modified glass-ionomer cement (RGIC) exhibited the lowest disintegration temperature (pcement (ZPC) and dual cure resin cement (RC) (p>0.05). Average separation temperatures: RGIC - 306 ± 23 °C, RC - 363 ± 71 °C, it could not be calculated for the ZPC due to the eight unseparated specimens. Within the limitations of the study, it could be concluded that RGIC cement disintegrates at the lowest temperature and ZPC is not prone to break down after exposure to temperature.

  16. Center for Cement Composite Materials

    Science.gov (United States)

    1990-01-31

    pastes have shown that the matrix is microporous; mesopores are absent unless the material is allowed to dry out. This results in water adsorption at low...only to water. When subsequently dried a portion of3 the porosity is converted to larger mesopores . • Only about one third of the cement reacts in a...Frictional sliding, in this case was characterized by a decreasing slope in the loading curve followed by hysteresis in the unload/reloading curves

  17. ROTARY SCREW SYSTEMS IN CEMENT

    OpenAIRE

    2016-01-01

    The article presents results of research of rotary-screw systems in relation to the creation of rotary kilns for the annealing of-cuttings in the preparation of cement clinker. Using the proposed design, in comparison with known designs of similar purpose, it significantly improves performance, reduces size and power consumption through the use of rotary screw systems in the form of screw rotors and drums made hollow with sidewalls assembled from separate strips or plates of different geometr...

  18. Some future tendencies in the electric power systems; Algunas tendencias futuras en los sistemas electricos de potencia

    Energy Technology Data Exchange (ETDEWEB)

    Sarmiento Uruchurtu, Hector Gerardo [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1995-12-31

    This document describes the most important tendencies on energy generation transmission and utilization of the electric power systems. The underlining of these tendencies has the purpose of maintaining a constant alert on the possible technological advances that must be covered at medium and long term in the Coordination Analysis of Transmission Systems [Espanol] En el presente documento se describen las tendencias mas importantes sobre generacion, transmision y utilizacion de la energia, en cuanto a los sistemas electricos de potencia. El destacar estas tendencias tiene por objeto una alerta constante sobre los posibles desarrollos tecnologicos que se deben abordar a mediano y largo plazo dentro de la Coordinacion de Analisis de Sistemas de Transmision

  19. Technological tendencies and their relation with energy markets; Tendencias tecnologicas y su relacion con mercados de energia

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez Castro, Salvador [Instituto de Investigaciones Electricas, Temixco, Morelos (Mexico)

    1999-07-01

    In this article some associate technological tendencies with areas of interest of the Control Systems Division of the Instituto de Investigaciones Electricas (IIE) are presented. Here the relations or influence that these tendencies have and will continue having in the future with the definition and implantation of energy markets are mentioned. [Spanish] En este articulo se presentan algunas tendencias tecnologicas asociadas con areas de interes de la Division de Sistemas de Control del Instituto de Investigaciones Electricas (IIE). Aqui se mencionan las relaciones o influencia que dichas tendencias tienen y continuaran teniendo en el futuro con la definicion e implantacion de mercados de energia.

  20. Los procesos penales en Europa: Líneas de evolución y tendencias de reforma

    OpenAIRE

    Gascón Inchausti, Fernando

    2009-01-01

    El presente trabajo pretende analizar las tendencias que han impulsado las reformas de los procesos penales en los países de Europa a partir de la segunda mitad del siglo XX, con especial atención al desarrollo legislativo en Alemania, Francia y Reino Unido, además de en España. En un primer momento, predominó el esfuerzo por reforzar las garantías del sujeto pasivo y por establecer modelos de proceso penal más acusatorios y contradictorios. A esta tendencia se le sumaron con posterioridad ot...

  1. Un contraste ADF secuencial para la detección de cambios en la tendencia estocástica

    OpenAIRE

    1999-01-01

    En este trabajo investigamos el comportamiento en muestras finitas de diversos contrastes secuenciales basados en el test de Dickey-Fuller aumentado (ADF). Los estadísticos considerados permiten contrastar dos hipótesis nulas: una raíz unitaria y estabilidad en Ia tendencia estocástica. Los resultados más sobresalientes son los siguientes. Los contrastes secuenciales de estabilidad en Ia tendencia estocástica presentan buena potencia y son bastante robustos a cambios en los parámetros ruidoso...

  2. Tendencias actuales en la educación superior : rumbos del mundo y rumbos del país

    OpenAIRE

    Restrepo Gómez, Bernardo

    2006-01-01

    Tendencias actuales en la educación superior: rumbos del mundo y rumbos del país El artículo presenta cuatro transformaciones que agitan las aguas de la educación superior en el mundo y particularmente en América Latina y Colombia en las últimas décadas. Tales tendencias tienen que ver con: 1) el manejo de los efectos de la globalización; 2) el fenómeno de la calidad; 3) los cambios pedagógicos, y 4) el emprendimiento o empresarismo. Cada uno de estos factores es desarrol...

  3. WHITE CEMENT IN SUSTAINABLE DEVELOPMENT

    Directory of Open Access Journals (Sweden)

    Y.C.P RAMANA BABU

    2013-04-01

    Full Text Available India is one among the fast developing countries in the world in the areas of Infrastructure. Now a day, Carbon monoxide (CO and carbon dioxide (CO2 are the temporary atmospheric pollutants in the environment chiefly emitted from the fuel burning vehicles and street lights which lead to global warming and pose a major threat tothe survival and sustainable development. This paper deals with the principal purpose of use of white cement in pavement design which will take care of the Green house gases (i.e., CO and CO2 and also saves lot of money in the long run process. A small amount of these gases in environment can cause major problems over time. Use of white cement in composite pavement design where there is heavy traffic loads are acting as well as number of vehicles are more such as junctions, bus stops, check posts etc., can perform better and acts asenvironment friendly. Its light colour reflects more than bituminous pavement so that it can be easily identified and avoid accidents to some extent. White cement helps to lower the average bus stop, junction temperature providing comfort to the people because it has high solar reflectance there by reducing “urban heat island” effect. In addition to this it has some more advantages which increase the sustainability, durability and workability of the pavements.

  4. Characterization of environmentally-friendly alkali activated slag cements and ancient building materials

    Science.gov (United States)

    Sakulich, Aaron Richard

    Alternative cement technologies are an area of increasing interest due to growing environmental concerns and the relatively large carbon footprint of the cement industry. Many new cements have been developed, but one of the most promising is that made from granulated, ground blast furnace slag activated by a high-pH solution. Another is related to the discovery that some of the pyramid limestone blocks may have been cast using a combination of diatomaceous earth activated by lime which provides the high pH needed to dissolve the diatomaceous earth and bind the limestone aggregate together. The emphasis of this thesis is not on the latter---which was explored elsewhere---but on the results supplying further evidence that some of the pyramid blocks were indeed reconstituted limestone. The goal of this work is to chemically and mechanically characterize both alkali-activated slag cements as well as a number of historic materials, which may be ancient analogues to cement. Alkali activated slag cements were produced with a number of additives; concretes were made with the addition of a fine limestone aggregate. These materials were characterized mechanically and by XRD, FTIR, SEM, and TGA. Samples from several Egyptian pyramids, an 'ancient floor' in Colorado, and the 'Bosnian Pyramids' were investigated. In the cements, it has been unequivocally shown that C-S-H, the same binding phase that is produced in ordinary portland cement, has been produced, as well as a variety of mineral side products. Significant recarbonation occurs during the first 20 months, but only for the Na2CO3-activated formulae. Radiocarbon dating proves that the 'Bosnian Pyramids' and 'ancient floors' are not made from any type of recarbonated lime; however, Egyptian pyramid limestones were finite, thus suggesting that they are of a synthetic nature. XRD and FTIR results were inconclusive, while TGA results indicate the limestones are identical to naturally occurring limestones, and SEM

  5. THE USE OF SISAL FIBRE AS REINFORCEMENT IN CEMENT BASED COMPOSITES

    Directory of Open Access Journals (Sweden)

    Romildo Dias Tolêdo Filho

    1999-08-01

    Full Text Available ABSTRACT The inclusion of fibre reinforcement in concrete, mortar and cement paste can enhance many of the engineering properties of the basic materials, such as fracture toughness, flexural strength and resistance to fatigue, impact, thermal shock and spalling. In recent years, a great deal of interest has been created worldwide on the potential applications of natural fibre reinforced, cement based composites. Investigations have been carried out in many countries on various mechanical properties, physical performance and durability of cement based matrices reinforced with naturally occurring fibres including sisal, coconut, jute, bamboo and wood fibres. These fibres have always been considered promising as reinforcement of cement based matrices because of their availability, low cost and low consumption of energy. In this review, the general properties of the composites are described in relation to fibre content, length, strength and stiffness. A chronological development of sisal fibre reinforced, cement based matrices is reported and experimental data are provided to illustrate the performance of sisal fibre reinforced cement composites. A brief description on the use of these composite materials as building products has been included. The influence of sisal fibres on the development of plastic shrinkage in the pre-hardened state, on tensile, compressive and bending strength in the hardened state of mortar mixes is discussed. Creep and drying shrinkage of the composites and the durability of natural fibres in cement based matrices are of particular interest and are also highlighted. The results show that the composites reinforced with sisal fibres are reliable materials to be used in practice for the production of structural elements to be used in rural and civil construction. This material could be a substitute asbestos-cement composite, which is a serious hazard to human and animal health and is prohibited in industrialized countries. The

  6. Incinerated sewage sludge ash as alternative binder in cement-based materials

    DEFF Research Database (Denmark)

    Krejcirikova, Barbora; Goltermann, Per; Hodicky, Kamil

    2013-01-01

    it can minimize the need of ash landfill disposal. The objective of this study is to show potential use of incinerated sewage sludge ash (ISSA), an industrial byproduct, as possible binder in cement-based materials. Chemical and mechanical characteristics are presented and compared with results obtained...

  7. Water dynamics in glass ionomer cements

    Science.gov (United States)

    Berg, M. C.; Jacobsen, J.; Momsen, N. C. R.; Benetti, A. R.; Telling, M. T. F.; Seydel, T.; Bordallo, H. N.

    2016-07-01

    Glass ionomer cements (GIC) are an alternative for preventive dentistry. However, these dental cements are complex systems where important motions related to the different states of the hydrogen atoms evolve in a confined porous structure. In this paper, we studied the water dynamics of two different liquids used to prepare either conventional or resin-modified glass ionomer cement. By combining thermal analysis with neutron scattering data we were able to relate the water structure in the liquids to the materials properties.

  8. Pulmonary Cement Embolism following Percutaneous Vertebroplasty

    Directory of Open Access Journals (Sweden)

    Ümran Toru

    2014-01-01

    Full Text Available Percutaneous vertebroplasty is a minimal invasive procedure that is applied for the treatment of osteoporotic vertebral fractures. During vertebroplasty, the leakage of bone cement outside the vertebral body leads to pulmonary cement embolism, which is a serious complication of this procedure. Here we report a 48-year-old man who was admitted to our hospital with dyspnea after percutaneous vertebroplasty and diagnosed as pulmonary cement embolism.

  9. Evaluation of cement production using a pressurized fluidized-bed combustor

    Energy Technology Data Exchange (ETDEWEB)

    DeLallo, M.; Eshbach, R.

    1994-01-01

    There are several primary conclusions which can be reached and used to define research required in establishing the feasibility of using PFBC-derived materials as cement feedstock. 1. With appropriate blending almost any material containing the required cement-making materials can be utilized to manufacture cement. However, extensive blending with multiple materials or the use of ash in relatively small quantities would compromise the worth of this concept. 2. The composition of a potential feedstock must be considered not only with respect to the presence of required materials, but just as significantly, with respect to the presence and concentration of known deleterious materials. 3. The processing costs for rendering the feedstock into an acceptable composition and the energy costs associated with both processing and burning must be considered. It should be noted that the cost of energy to produce cement, expressed as a percentage of the price of the product is higher than for any other major industrial product. Energy consumption is, therefore, a major issue. 4. The need for conformance to environmental regulations has a profound effect on the cement industry since waste materials can neither be discharged to the atmosphere or be shipped to a landfill. 5. Fifth, the need for achieving uniformity in the composition of the cement is critical to controlling its quality. Unfortunately, certain materials in very small concentrations have the capability to affect the rate and extent to which the cementitious compound in portland cement are able to form. Particularly critical are variations in the ash, the sulfur content of the coal or the amount and composition of the stack dust returned to the kiln.

  10. Leaf structural traits of tropical woody species resistant to cement dust.

    Science.gov (United States)

    Siqueira-Silva, Advanio Inácio; Pereira, Eduardo Gusmão; Modolo, Luzia Valentina; Paiva, Elder Antonio Sousa

    2016-08-01

    Cement industries located nearby limestone outcrops in Brazil have contributed to the coating of cement dust over native plant species. However, little is known about the extent of the response of tropical woody plants to such environmental pollutant particularly during the first stages of plant development and establishment. This work focused on the investigation of possible alterations in leaf structural and ultrastructural traits of 5-month-old Guazuma ulmifolia Lam. (Malvaceae), 6-month-old Myracrodruon urundeuva Allemão (Anacardiaceae), and 9-month-old Trichilia hirta L. (Meliaceae) challenged superficially with cement dust during new leaf development. Leaf surface of plants, the soil or both (leaf plus soil), were treated (or not) for 60 days, under controlled conditions, with cement dust at 2.5 or 5.0 mg cm(-2). After exposure, no significant structural changes were observed in plant leaves. Also, no plant death was recorded by the end of the experiment. There was also some evidence of localized leaf necrosis in G. ulmifolia and T. hirta, leaf curling in M. urundeuva and T. hirta, and bulges formation on epidermal surface of T. hirta, after cement dust contact with plant shoots. All species studied exhibited stomata obliteration while T. hirta, in particular, presented early leaf abscission, changes in cellular relief, and organization and content of midrib cells. No significant ultrastructural alterations were detected under the experimental conditions studied. Indeed, mesophyll cells presented plastids with intact membrane systems. The high plant survival rates, together with mild morphoanatomic traits alterations in leaves, indicate that G. ulmifolia is more resistant to cement dust pollutant, followed by M. urundeuva and T. hirta. Thus, the three plant species are promising for being used to revegetate areas impacted by cement industries activities.

  11. Biomonitoring of airborne particulate matter emitted from a cement plant and comparison with dispersion modelling results

    Science.gov (United States)

    Abril, Gabriela A.; Wannaz, Eduardo D.; Mateos, Ana C.; Pignata, María L.

    2014-01-01

    The influence of a cement plant that incinerates industrial waste on the air quality of a region in the province of Córdoba, Argentina, was assessed by means of biomonitoring studies (effects of immission) and atmospheric dispersion (effects of emission) of PM10 with the application of the ISC3 model (Industrial Source Complex) developed by the USEPA (Environmental Protection Agency). For the biomonitoring studies, samples from the epiphyte plant Tillandsia capillaris Ruíz & Pav. f. capillaris were transplanted to the vicinities of the cement plant in order to determine the physiological damage and heavy metal accumulation (Ca, Mn, Fe, Co, Ni, Cu, Zn, Cd and Pb). For the application of the ISC3 model, point and area sources from the cement plant were considered to obtain average PM10 concentration results from the biomonitoring exposure period. This model permitted it to be determined that the emissions from the cement plant (point and area sources) were confined to the vicinities, without significant dispersion in the study area. This was also observed in the biomonitoring study, which identified Ca, Cd and Pb, pH and electric conductivity (EC) as biomarkers of this cement plant. Vehicular traffic emissions and soil re-suspension could be observed in the biomonitors, giving a more complete scenario. In this study, biomonitoring studies along with the application of atmospheric dispersion models, allowed the atmospheric pollution to be assessed in more detail.

  12. The influence of ultrasound on removal of prefabricated metal post cemented with different resin cements

    Directory of Open Access Journals (Sweden)

    Atiyeh Feiz

    2013-01-01

    Conclusion: Ultrasonic energy did not decrease the retention of posts cemented with Panavia or Maxcem Elite cements. Furthermore, it seems that there is no significant difference between removal force of self-etch (Panavia and the self-etch self-adhesive (Maxcem Elite resin cements.

  13. Effects of cement flue dusts from a Nigerian cement plant on air, water and planktonic quality.

    Science.gov (United States)

    Olaleye, Victor F; Oluyemi, Emmanuel A

    2010-03-01

    Effects of cement flue dust from Ewekoro cement Kilns were monitored at some aquatic receptor locations. High levels of total suspended particulates (TSPs) and atmospheric deposition rates (ADRs) were recorded within the factory compared to ancillary locations outside the factory. The TSP and ADR levels which were location dependent were significantly higher (P cement factory catchment areas.

  14. The mechanical effects of different levels of cement penetration at the cement-bone interface.

    NARCIS (Netherlands)

    Waanders, D.; Janssen, D.; Mann, K.A.; Verdonschot, N.J.J.

    2010-01-01

    The mechanical effects of varying the depth of cement penetration in the cement-bone interface were investigated using finite element analysis (FEA) and validated using companion experimental data. Two FEA models of the cement-bone interface were created from micro-computed tomography data and the p

  15. Frozen delivery of brushite calcium phosphate cements.

    Science.gov (United States)

    Grover, Liam M; Hofmann, Michael P; Gbureck, Uwe; Kumarasami, Balamurgan; Barralet, Jake E

    2008-11-01

    Calcium phosphate cements typically harden following the combination of a calcium phosphate powder component with an aqueous solution to form a matrix consisting of hydroxyapatite or brushite. The mixing process can be very important to the mechanical properties exhibited by cement materials and consequently when used clinically, since they are usually hand-mixed their mechanical properties are prone to operator-induced variability. It is possible to reduce this variability by pre-mixing the cement, e.g. by replacing the aqueous liquid component with non-reactive glycerol. Here, for the first time, we report the formation of three different pre-mixed brushite cement formulations formed by freezing the cement pastes following combination of the powder and liquid components. When frozen and stored at -80 degrees C or less, significant degradation in compression strength did not occur for the duration of the study (28 days). Interestingly, in the case of the brushite cement formed from the combination of beta-tricalcium phosphate with 2 M orthophosphoric acid solution, freezing the cement paste had the effect of increasing mean compressive strength fivefold (from 4 to 20 MPa). The increase in compression strength was accompanied by a reduction in the setting rate of the cement. As no differences in porosity or degree of reaction were observed, strength improvement was attributed to a modification of crystal morphology and a reduction in damage caused to the cement matrix during manipulation.

  16. Hidration kinetics study of tlie mixed cements

    OpenAIRE

    Duque Fernández, Gabriel . L; Díaz Quintanilla, David; Zapata Sierra, Manuel; Rubio Frías, Ester

    1993-01-01

    A study of the hydration process of cements with 10% and 20% addition of a tuff from "Las Carolinas" quarry (Cienfuegos, Cuba) by different methods was done. The results obtained by different methods showed a good agreement. It was proved an increment of the hydration products, an acceleration of alite hydration and a swelling of the fixed water in mixed cements. The resistance of the cement with 10% addition is similar to that of the pure cement for ages of 28 days, whereas with 20% addition...

  17. Properties of Cement Mortar Containing Rubber Ash as Sand Replacement

    Science.gov (United States)

    Syamir Senin, Mohamad; Shahidan, Shahiron; Syazani Leman, Alif; Izzati Raihan Ramzi Hannan, Nurul

    2016-11-01

    Discarded scrap tyres have become one of the major environmental problems nowadays. There has been increasing public worry about the mining of natural resources in recent years. In order to minimize the consumption of natural resources, rubber ash has been postulated as a potential material for partial replacement of sand in concrete materials especially for applications which are subjected to impact and vibration such as road and bridge construction. Thus, it contributes to the development of the construction industry in a sustainable way. This paper mainly emphasizes on the use of rubber ash from waste tyres in cement mortar. 100mm cubic specimens were produced by adding rubber ash volume ratios of 0%, 3%, 5% and 7% as sand replacement in M30 quality cement mortar. A compressive stress test and a density test were conducted at the end of 7, 14, and 28 days. The result shows that 5% is the optimum value for sand replacement in the cement mortar. Therefore, rubber ash is acceptable to be used as sand replacement.

  18. Partial Replacement of Cement with Marble Dust Powder

    Directory of Open Access Journals (Sweden)

    Mr. Ranjan Kumar

    2015-08-01

    Full Text Available The waste generated from the industries cause environmental problems. Hence the reuse of this waste material can be emphasized. MarbleDust Powder (MDP is a developing composite materialthatwillallow the concrèteindustry to optimisemateriel use, generateeconomicbenefits and build structures thatwillstrong, durable and sensitive to environnement. MDP is by-product obtained during the quarrying process from the parent marble rock; which contains high calcium oxide content of more than 50%. The potential use of MDP can be an ideal choice for substituting in a cementitious binder as the reactivity efficiency increases due to the presence of lime. In this research work, the waste MDP passing through 90 microns,has used for investigating of hardened concrete properties. Furthermore, the effect of different percentage replacement of MDP on the compressive strength, splitting tensile strength (indirect tensile strength&flexural strength has been observed. Inthis experimental study, the effect of MDP in concrete on strength ispresented. Five concrete mixtures containing 0%, 5%, 10%, and 20% MDP as cement replacement by weightbasis has been prepared. Water/cement ratio (0.43 was kept constant, in all the concretemixes. Compressive strength, split tensile strength & flexural strength of the concrete mixtures has been obtainedat 7 and 28 days. The results of the laboratory work showed thatreplacement of cement with MDP increase, upto 10% for compressive strength,&upto 15% for split tensilestrength &flexural strength of concrete.

  19. Resistência mecânica de compósitos cimentícios leves utilizando resíduos industriais e fibras de sisal Mechanical resistence of lightweight cement composites utilizing industrial residues and fibers of sisal

    Directory of Open Access Journals (Sweden)

    Nivaldo T. de Arruda Filho

    2012-08-01

    Full Text Available A valorização de materiais alternativos incorporados com resíduos como opção ao convencional deve possibilitar a geração de um produto com qualidade, estética, produtividade e com potencial de reduzir impactos da poluição ambiental. Este trabalho foi realizado com o objetivo de desenvolver elementos construtivos para forro e divisórias, a partir de matrizes cimentícias com incorporação de resíduos industriais (resíduo cerâmico, etil vinil acetato - EVA e fibras de sisal. Desenvolveram-se técnicas de moldagem em matrizes cimentícias autoadensáveis e se avaliou a resistência mecânica dos novos compósitos. Uma placa com resíduos de EVA foi produzida e, através de trabalhos de reologia, encontrou-se a pasta matriz de revestimento desta placa, com teor adequado de adições pozolânicas e aditivo superplastificante. Avaliaram-se as resistências mecânicas das placas, da pasta matriz de revestimento encontrada, com e sem adição de fibras, e do novo compósito formado pela união desses dois elementos. Utilizou-se a técnica de alinhamento de fibras com o intuito de incrementar resistência ao novo compósito leve. A adição da matriz com fibras alinhadas melhorou a resistência a flexão do novo compósito.The appreciation of alternative materials incorporated in waste as an option to conventional material should enable to generate a product with quality, aesthetics, productivity and reduce the potential impacts of environmental pollution. This study aims to develop constructive elements for ceilings and walls from cementitious matrix incorporating industrial waste (ceramic waste, ethyl vinyl acetate - EVA and sisal fibers. Moulding techniques to produce self-compacting cementitious matrices were developed and the strength of the new composites were evaluated. A plate with EVA waste was produced and through rheology studies, a matrix plaster for coating of plate surface was found, with appropriate content of pozzolanic and

  20. 浅析水泥包装袋的质量%Analysis of the Quality of the Cement Packaging Bags

    Institute of Scientific and Technical Information of China (English)

    张静

    2013-01-01

    With economic development in recent years, the construction industry has also made good benefits. The prosperity of construction industry also played a role in promoting the development of cement and other related industries. At the same time, the quality issues of cement industry are also concerned, especially the cement packaging quality problems. There are a lot of cement packaging bags that do not meet national standards inn the market. Fundamentally speaking, it is related to the business ideas of cement production enterprises. This paper analyzed the quality problems of cement packaging bags and other related issues in the cement industry and found solutions.%  近几年随着经济的发展,建筑行业也取得了良好的效益。建筑行业的繁荣对水泥等相关产业的发展也起到了推动作用。但与此同时,水泥行业的产品质量问题也倍受关注。特别是水泥包装的质量问题尤为突出。市场上出现了大量不符合国家标准的水泥包装袋,从根本上讲,这与水泥生产企业的经营思想不无关系。本文主要就水泥包装袋方面的质量问题及水泥行业的其他相关问题进行分析,并寻求解决办法。

  1. A study on provisional cements, cementation techniques, and their effects on bonding of porcelain laminate veneers.

    Science.gov (United States)

    Vinod Kumar, G; Soorya Poduval, T; Bipin Reddy; Shesha Reddy, P

    2014-03-01

    Minimal tooth preparation is required for porcelain laminate veneers, but interim restorations are a must to protect their teeth against thermal insult, chemical irritation, and to provide aesthetics. Cement remaining after the removal of the provisional restoration can impair the etching quality of the tooth surface and fit and final bonding of the porcelain laminate veneer. This in vitro study examined the tooth surface for remaining debris of cement after removal of a provisional restoration. Determine the presence of cement debris on prepared tooth surface subsequent to the removal of provisional restoration. Determine the cement with the least residue following the cleansing procedures. Determine the effect of smear layer on the amount of residual luting cement. Eighty-four extracted natural anterior teeth were prepared for porcelain laminate veneers. For half of the teeth, the smear layer was removed before luting provisional restorations. Veneer provisional restorations were fabricated and luted to teeth with six bonding methods: varnish combined with glass ionomer cement (GIC), varnish combined with resin modified GIC, varnish, spot etching combined with dual-cure luting cement, adhesive combined with GIC, adhesive combined with resin modified GIC, and adhesive, spot etching combined with dual-cure luting cement. After removal of provisional restorations 1 week later, the tooth surface was examined for residual luting material with SEM. Traces of cement debris were found on all the prepared teeth surfaces for all six groups which were cemented with different methods. Cement debris was seen on teeth subsequent to the removal of provisional's. Dual-cure cement had the least residue following the cleansing procedures. Presence of smear layer had no statistical significance in comparison with cement residue. With the use of adhesive the cement debris was always found to be more than with the use of varnish. GIC showed maximum residual cement followed by dual-cure.

  2. Tendencias mundiales en educación médica Tendencias mundiales en educación médica

    Directory of Open Access Journals (Sweden)

    Ricardo Posada Saldarriaga

    2004-02-01

    Full Text Available This article presents a general view of some considerations made by medical educators in the world, with the objective to leave to the reader elements for the reflection and the possibilitie of propose new educative strategies. It has the purpose of sugesting new Educative strategies for medical education in our country as in other regions of the world. The propose tendencies are: Globalization multidisciplinal activities and fortification of some areas within the curriculum of medicina, such as: Basic sciences, Investigation, Public Health and the Humanistic formation. Aditionally, some methodologies of education have appeared that have demonstrated to be complement of traditional classroom activities, laboratory and clinical rotations. Some of these methodologies are mentioned: simulation, use of technologies of information and communication (TIC, Evidence Based Medicine (EBM and Based Problem Learning. To confront the new challenges raised worldwide in the medical education and to maintain high quality standards, it is necessary that faculties of medicine understand the accelerated changes that are presently occurring. It is necessary to innovate in educational methodologies that foment the selflearning and active participation in learning process, implement the new information technologies, fortify the interrelation between basic and clinics sciences, thus fomenting partner-humanistic formation and public health aspects, creating research lines in which the students may participate actively to promote a flexible curriculum which allows our students to strenghten knowledge areas of their interest. Este artículo presenta de manera general algunas reflexiones hechas por educadores médicos en el mundo, con el objetivo de dejar al lector elementos para la reflexión y para la proposición de nuevas estrategias educativas en su quehacer docente. Se presentan las que a nuestro juicio pueden ser consideradas tendencias para la educación de los m

  3. Cadenas de rodillos. Tendencias de desarrollo y dimensionales según normas ISO.

    Directory of Open Access Journals (Sweden)

    M. E. García Domínguez

    2007-05-01

    Full Text Available El artículo es una compilación de resultados derivados de un estudio del desarrollo de la transmisión por cadena de rodillos que permite brindar información relevante sobre la tendencia del mercado internacional, innovaciones recientes en las cadenas de rodillos y las diferencias dimensionales que caracterizan las series geométricas de las cadenas ISO-A e ISO-B según la norma ISO 606:2004The paper is a compilation of some results associated with the development of roller chain transmissions and outstanding information in relations with the roller chain market trend, recent innovations and dimensional differences of ISO-A and ISO-B roller chain series according to ISO Standard 606:2004.

  4. Tendencias e Instrumentos de Integración Regional en Latinoamericana y el Caribe

    Directory of Open Access Journals (Sweden)

    Maria Carolina Moreno

    2017-02-01

    Full Text Available El presente artí­culo es una revisión del tema de integración Latinoamericana y el Caribe desde una perspectiva inter y multidisciplinar que comprenden los procesos históricos de los paí­ses miembros, los análisis de la CEPAL tales como la teorí­a de la dependencia, el Sistema de Sustitución de Importaciones ISI, la heterogeneidad estructural de la región, el regionalismo abierto como resultado de las reformas económicas estructurales de finales de los años 80 y principios de los 90, y las nuevas tendencias o transformaciones de la integración en el marco de las teorí­as de las relaciones internacionales RI

  5. Tendencias de la historia regional en Colombia. Problemas y perspectivas recientes

    Directory of Open Access Journals (Sweden)

    Renzo Ramírez Bacca

    2011-06-01

    Full Text Available El texto ofrece un balance de los estudios regionales en Colombia. Los elementos de la interpretación que tiene el autor son los siguientes: 1 Una comprensión contextual sobre la institucionalización de la disciplina. 2 Un análisis sobre las posibilidades y problematización del concepto Región. 3 Un balance crítico sobre la producción monográfica regional, con énfasis especial en el caso antioqueño. Y, 4 una mirada sobre las tendencias recientes en los estudios regionales a partir de la producción visible en el Sistema Nacional de Investigación y Colciencias, e información ofrecida por algunos departamentos de historia del país.

  6. Tendencia de la incidencia de los tumores hepáticos en la infancia

    Directory of Open Access Journals (Sweden)

    Mejía-Aranguré Juan Manuel

    2002-01-01

    Full Text Available Objetivo. Evaluar la tendencia de la incidencia de los diferentes tumores hepáticos en niños residentes en el Distrito Federal. Material y métodos. Encuesta hospitalaria. Se realizó un análisis de dos bases de datos. La primera tiene registrados todos los casos de tumores hepáticos que se encontraron entre el periodo de l982 a 1991, de hospitales que atienden a niños con cáncer, residentes en la Ciudad de México. La segunda base de datos tiene registrados todos los casos de tumores hepáticos que se encontraron de 1996 a 1999 en el Hospital de Pediatría Centro Médico Nacional (CMN "Siglo XXI" y en el Hospital General del Centro Médico Nacional "La Raza", del Instituto Mexicano del Seguro Social (IMSS. Se calcularon las tasas de incidencia anual promedio (TIAP por cada tipo de tumor hepático. Las tasas fueron estandarizadas por el método directo, usando como población de referencia a la mundial estándar menor de l5 años. La tendencia se evaluó con las tasas de incidencia anuales y se calculó la tasa de cambio promedio que emplea la distribución de Poisson. Resultados. Durante el periodo de 1982 a 1991 la TIAP para hepatoblastoma fue el triple en hombres con 0.6 x 10(6. El grupo más afectado fue el de 1 a 4 años.(Para los hepatocarcinomas la TIAP fue de 0.14 para el sexo femenino, siendo el doble que la del sexo masculino. Para el periodo de 1996 a 1999 la TIAP para hepatoblastomas fue de 5.11 en mujeres y de 1.85 en hombres. El grupo de edad con la tasa más alta fue el de mujeres menores de un año. Para hepatocarcinomas la TIAP fue de 0.64 para hombres y de 1.23 en mujeres. El grupo de edad más afectado fue el de hombres de 10 a 14 años. No se observó tendencia significativa al incremento o decremento en la incidencia de hepatoblastomas. Para hepatocarcinomas hubo una tasa de cambio de 10%, pero tampoco fue significativa. Conclusiones. No existe en la Ciudad de México una tendencia en la incidencia de los tumores hep

  7. Magnitud y tendencia del suicidio en las provincias de Costa Rica: 1980 - 1994

    OpenAIRE

    Damaris Granados Bloise

    1998-01-01

    En el primer artículo de la serie, publicado en el número anterior de esta Revista (1), se analizó, para Costa Rica como un todo, la magnitud, estructura por edad y sexo y tendencia del suicidio en el período 1980 - 1994. En esta segunda entrega se amplía el estudio a nivel de provincia. (2) (3) (4) (5) de las 2.015 muertes por suicidio registradas entre 1980 - 1994, el 39% correspondió a residentes de la provincia de San José, el 17% de Alajuela y el 11% de Limón. La más alta tasa promedio a...

  8. Coherencia de tendencias en cosmética, con procesos de I+D en BELCORP

    Directory of Open Access Journals (Sweden)

    Iván Felipe Acosta

    2016-07-01

    Full Text Available La constante necesidad de las empresas por actualizarse o reinventarse para mantenerse vigentes en el mercado ha llevado a que tengan como estrategia la implementación de modelos de Innovación y Desarrollo (I+D. BELCORP, una empresa del sector cosmético ha implementado un sistema denominado Stage Gate, una metodología eficiente para el desarrollo de productos que comprende desde la conceptualización hasta la etapa posterior al lanzamiento y la comercialización de sus productos. Para garantizar su éxito, BELCORP tiene como estrategia mantenerse al día con las tendencias de la moda vigente pero, para lanzar sus productos también está considerando otros factores como los gustos de los consumidores, la cultura y las posibilidades tecnológicas existentes en los mercados donde tiene presencia.

  9. La tendencia ambiental urbana en ciudades intermedias. Una propuesta metodológica

    Directory of Open Access Journals (Sweden)

    Pinzón Botero María Victoria

    2011-11-01

    Full Text Available Desde las últim as décadas, es evidente la preocupación m undial por los im pactos ambientales negativos que ponen en riesgo la sostenibilidad urbana y su calidad ambiental. Diferentes estudios exponen las variables más importantes para minim izar estos impactos ambientales, y en este sentido, este trabajo de investigación muestra cómo a partir de un diseño metodológico más sencillo con 27 variables am bientales estratégicas, es posible evaluar la tendencia am biental urbana de ciudades intermedias. Este grupo priorizado de variables trabajadas en el marco de una gestión compartida, orientará el desarrollo de la ciudad hacia una estructura territorial más sostenible, como reto para la planificación ambiental actual y con visión de futuro.

  10. El programa de termalismo social del IMSERSO. Evolución y tendencias de futuro

    Directory of Open Access Journals (Sweden)

    Olga Martínez Moure

    2013-10-01

    Full Text Available El Programa de Termalismo del IMSERSO, perteneciente al Instituto de Mayores y Servicios Sociales del Gobierno de España, se encuentra englobado dentro de de las políticas y actuaciones públicas de carácter social y económico que tienen como objetivo favorecer la salud e integración social de las personas mayores y su envejecimiento activo. Este artículo estudia, desde el año 2010 hasta el 2013, la evolución de las plazas adscritas al programa y hace una prospección para 2014-2015. Los resultados revelan una disminución generalizada del número de plazas, tendencia que se mantendrá en los próximos años.

  11. LOS DERECHOS ECONÓMICOS, SOCIALES Y CULTURALES Y LA JUSTICIA CONSTITUCIONAL LATINOAMERICANA: TENDENCIAS JURISPRUDENCIALES

    Directory of Open Access Journals (Sweden)

    Claudio Nash Rojas

    2011-01-01

    Full Text Available El objetivo de este estudio es revisar algunos casos relevantes de la jurisprudencia latinoamericana en materia de aplicación de los derechos económicos, sociales y culturales. Se estudiará jurisprudencia constitucional latinoamericana reciente en materia de DESC. El trabajo establece algunos estándares generales en materia de derechos económicos, sociales y culturales en el ámbito internacional, revisa algunos ejemplos destacados a nivel comparado en Latinoamérica, establece la forma en que esta interpretación está enriqueciendo estos derechos consagrados constitucionalmente, y analiza los alcances de esta discusión en Chile y ciertas tendencias interesantes en el ámbito hermenéutico y jurisprudencial.

  12. Una mirada conjugada en la gestión cultural estadounidense: tendencias actuales.

    Directory of Open Access Journals (Sweden)

    Jodie Dinapoli Algarra

    2015-06-01

    Full Text Available Debido al descenso que se experimenta en Estados Unidos en la participación del público en los eventos culturales, las instituciones y organizaciones culturales ponen el énfasis en cómo desarrollar un nuevo público y reflexionan sobre el impacto que pueden alcanzar más allá de sus paredes físicas. Este impacto se dirige al desarrollo humano, a la revitalización urbana, al bienestar social y a la creación activa de la cultura. En línea con esta misión y visión encontramos actividades y programas que se llevan a cabo en espacios no tradicionales, que expanden la cooperación social desplazando el foco institucional hacia la creatividad, dirigiendo el objetivo hacia el diálogo crítico, construyendo participación cultural significativa, desafiando el paisaje interno de la organización y sus procesos para servir mejor a la comunidad y a su entorno.  Este artículo analiza esta tendencia por medio de casos específicos de instituciones de artes visuales y estudia conceptos comunes que entran en juego tales como la cooperación social y el valor público. Este texto incorpora un contexto histórico y cuestiona la percepción pública de estas tendencias y su relación con el sector sin ánimo de lucro y su particular modelo de financiación.

  13. La tendencia post gerencial en la determinación de la cultura organizacional del futuro

    Directory of Open Access Journals (Sweden)

    Lucas del Moral

    2000-09-01

    Full Text Available Este artículo nace de la necesidad de superar la falta de definición conceptual de lo que enfrentaremos en el futuro casi inmediato en el mundo de la administración de empresas y tuvo como finalidad la revisión bibliográfica desde el punto de vista del método de investigación documental-cualitativa, sobre una de las recientes tendencias de la Gerencia. Enfoca la atención sobre las tareas pasadas, actuales y futuras del Management y su influencia contemporánea en la determinación de la cultura Organizacional y como el nuevo fenómeno perceptual de la postgerencia del nuevo siglo afectará con la respectiva cuota de déficit conceptual, la misma Cultura Organizacional y Corporativa. Este artículo proporciona una interpretación de los investigadores y teóricos de más reciente data, que se han atrevido a advertir al mundo sobre la actual situación de la tarea de dirección de empresas. Su evolución hacia otra forma, enfoque y concepto de gerencia. Mas el autor salva asertivamente su responsabilidad en cuanto a definir lo que está ya implantado en las administraciones más avanzadas del mundo y advierte que el déficit conceptual que padece esta tendencia ahonda y profundiza su aceptación en la alta gerencia organizacional y empresarial en los países emergentes, para dinamizar el cambio necesario en su total implantación.

  14. PRÁCTICAS LECTORAS: COMPRENSIÓN Y EVALUACIÓN. TENDENCIAS, ESTADO Y PROYECCIONES

    Directory of Open Access Journals (Sweden)

    Jairo Aníbal Moreno Castro

    2010-01-01

    Full Text Available En este artículo se revisan, discuten y sistematizan asuntos teóricos fundamentales que apoyan la primera fase de la investigación ¿Evaluación de los niveles de lectura en el contexto de la educación superior¿, desarrollada durante el periodo 2009-2010. El concepto de lectura, las conexiones que tal modalidad comunicativa humana sostiene con la comprensión discursiva y, finalmente, las perspectivas y estrategias evaluativas de la comprensión lectora en entornos académicos institucionalizados son los ejes temáticos del artículo. Este último se propone señalar con precisión tanto el estado como las tendencias y proyecciones conceptuales y programáticas de tales nodos temáticos. Con el propósito de fortalecer la consistencia conceptual, facilitar la comprensión crítica y aligerar la textura académica del artículo, el análisis de los documentos revisados se presenta integrado alrededor de cuatro tópicos considerados como las tendencias conceptuales nucleares: 1 el tránsito de lo sensorial a lo racional y de lo racional a lo sociocultural transaccional, 2 el tránsito del significante al significado y de allí al sentido, 3 el tránsito de lo textual a lo intertextual y de allí a lo contextual (lo literal, lo inferencial, lo crítico, y 4 el tránsito de la lectura como comportamiento a la lectura como proceso.

  15. PRÁCTICAS LECTORAS: COMPRENSIÓN Y EVALUACIÓN. TENDENCIAS, ESTADO Y PROYECCIONES

    Directory of Open Access Journals (Sweden)

    Jairo Aníbal Moreno Castro

    2010-06-01

    Full Text Available En este artículo se revisan, discuten y sistematizan asuntos teóricos fundamentales que apoyan la primera fase de la investigación "Evaluación de los niveles de lectura en el contexto de la educación superior", desarrollada durante el periodo 2009-2010. El concepto de lectura, las conexiones que tal modalidad comunicativa humana sostiene con la comprensión discursiva y, finalmente, las perspectivas y estrategias evaluativas de la comprensión lectora en entornos académicos institucionalizados son los ejes temáticos del artículo. Este último se propone señalar con precisión tanto el estado como las tendencias y proyecciones conceptuales y programáticas de tales nodos temáticos. Con el propósito de fortalecer la consistencia conceptual, facilitar la comprensión crítica y aligerar la textura académica del artículo, el análisis de los documentos revisados se presenta integrado alrededor de cuatro tópicos considerados como las tendencias conceptuales nucleares: 1 el tránsito de lo sensorial a lo racional y de lo racional a lo sociocultural transaccional, 2 el tránsito del significante al significado y de allí al sentido, 3 el tránsito de lo textual a lo intertextual y de allí a lo contextual (lo literal, lo inferencial, lo crítico, y 4 el tránsito de la lectura como comportamiento a la lectura como proceso.

  16. Trabajo y salud en la industria maquiladora mexicana: una tendencia dominante en el neoliberalismo dominado

    Directory of Open Access Journals (Sweden)

    Jorge Villegas

    Full Text Available Se analizan las condiciones laborales y de salud de los trabajadores de la Industria Maquiladora de Exportación en México. Hace uso intensivo de la fuerza de trabajo mayoritariamente femenina,constituye la segunda fuente de divisas. Ilustra una tendencia dominante en el neoliberalimo respecto a condiciones de trabajo y salud, permite apreciar el impacto de la generalizada flexibilización laboral y del creciente cambio tecnológico. El panorama de los riesgos y exigencias es complejo. En la organización laboral persisten exigencias del taylorismo, los riesgos químicos son múltiples y con probables efectos que rebasan el ámbito laboral, también existen exigencias de trabajo repetitivo y posiciones incómodas. Las repercusiones en la salud muestran elevados índices de morbilidad por demanda en los servicios de seguridad social, entre 2 y 4 veces más altos que para otros trabajadores industriales. Padecimientos asociados al estrés ocupan elevado porcentaje entre los motivos de consulta. También se muestran repercusiones en las familias, el bajo peso al nacer de los hijos es un riesgo 2.8 veces mayor para obreras de la maquila respecto de otros grupos de trabajadoras. Los accidentes laborales alcanzan cifras elevada y llegando a ser la segunda causa de consulta en algunos casos. Este análisis permite identificar algunas tendencias que en la salud laboral pueden ser importantes en los próximos años para amplios grupos de trabajadores.

  17. Trabajo y salud en la industria maquiladora mexicana: una tendencia dominante en el neoliberalismo dominado

    Directory of Open Access Journals (Sweden)

    Villegas Jorge

    1997-01-01

    Full Text Available Se analizan las condiciones laborales y de salud de los trabajadores de la Industria Maquiladora de Exportación en México. Hace uso intensivo de la fuerza de trabajo mayoritariamente femenina,constituye la segunda fuente de divisas. Ilustra una tendencia dominante en el neoliberalimo respecto a condiciones de trabajo y salud, permite apreciar el impacto de la generalizada flexibilización laboral y del creciente cambio tecnológico. El panorama de los riesgos y exigencias es complejo. En la organización laboral persisten exigencias del taylorismo, los riesgos químicos son múltiples y con probables efectos que rebasan el ámbito laboral, también existen exigencias de trabajo repetitivo y posiciones incómodas. Las repercusiones en la salud muestran elevados índices de morbilidad por demanda en los servicios de seguridad social, entre 2 y 4 veces más altos que para otros trabajadores industriales. Padecimientos asociados al estrés ocupan elevado porcentaje entre los motivos de consulta. También se muestran repercusiones en las familias, el bajo peso al nacer de los hijos es un riesgo 2.8 veces mayor para obreras de la maquila respecto de otros grupos de trabajadoras. Los accidentes laborales alcanzan cifras elevada y llegando a ser la segunda causa de consulta en algunos casos. Este análisis permite identificar algunas tendencias que en la salud laboral pueden ser importantes en los próximos años para amplios grupos de trabajadores.

  18. Tendencias de mortalidad por traumatismos y envenenamientos en adolescentes: México, 1979-1997

    Directory of Open Access Journals (Sweden)

    Celis Alfredo

    2003-01-01

    Full Text Available OBJETIVO: Describir las causas externas de la mortalidad por traumatismos y envenenamientos, así como la tendencia que estas causas han mostrado entre adolescentes en México, de 1979 a 1997. MATERIAL Y MÉTODOS: Para la realización de este estudio descriptivo de la mortalidad se utilizaron las bases de datos de mortalidad registrada en México de 1979 a 1997. Los datos son recabados, codificados y capturados por el Instituto Nacional de Estadística, Geografía e Informática, y se obtuvieron a través del Instituto Nacional de Salud Pública. Los datos fueron tabulados durante el último semestre de 2000, en Jalisco, en la Unidad de Investigación Epidemiológica y en Servicios de Salud del Adolescente del Instituto Mexicano del Seguro Social. RESULTADOS: Los traumatismos y envenenamientos ocuparon el primer lugar en la mortalidad del grupo adolescente (tasa de 13.35/100 000 con una tendencia descendente de -41.4% durante el periodo 1979-1997, no obstante el incremento de homicidios y suicidios (9.5% y 104.0% respectivamente. Los mecanismos más frecuentes fueron los vehículos de tráfico de motor, las armas de fuego, las intoxicaciones, las sofocaciones y las asfixias por inmersión. CONCLUSIONES: Los traumatismos y envenenamientos que experimenta la población de países en desarrollo muestran frecuencias diferentes a lo registrado en los más desarrollados, haciendo necesario el estudio de los mismos para implantar las medidas preventivas acordes con las condiciones socioculturales y ambientales de cada entorno.

  19. El deporte y la podología: tendencias actuales en ortopodología (primera parte)

    OpenAIRE

    Dorca Coll, Adelina; Céspedes Céspedes, Tomás; Cuevas Gómez, Rafael; Sacristán Valero, Sergi

    1993-01-01

    Se pretende revisar los conceptos y criterios que se venían aplicando en ortopodología y exponer las tendencias actuales tanto en la valoración de los parámetros previos al diseño ortopodológico como en la confección del tratamiento.

  20. Application of Neutron imaging in pore structure of hydrated wellbore cement: comparison of hydration of H20 with D2O based Portland cements

    Science.gov (United States)

    Dussenova, D.; Bilheux, H.; Radonjic, M.

    2012-12-01

    Wellbore Cement studies have been ongoing for decades. The studies vary from efforts to reduce permeability and resistance to corrosive environment to issues with gas migration also known as Sustained Casing Pressure (SCP). These practical issues often lead to health and safety problems as well as huge economic loss in oil and gas industry. Several techniques have been employed to reduce the impact of gas leakage. In this study we purely focus on expandable liners, which are introduced as part of oil well reconstruction and work-overs and as well abandonment procedures that help in prevention of SCP. Expandable liner is a tube that after application of a certain tool can increase its diameter. The increase in diameter creates extra force on hydrated cement that results in reducing width of interface fractures and cement-tube de-bonding. Moreover, this also causes cement to change its microstructure and other porous medium properties, primarily hydraulic conductivity. In order to examine changes before and after operations, cement pore structure must be well characterized and correlated to cement slurry design as well as chemical and physical environmental conditions. As modern oil well pipes and tubes contain iron, it is difficult to perform X-ray tomography of a bulk measurement of the cement in its wellbore conditions, which are tube wall-cement-tube wall. Neutron imaging is a complementary technique to x-ray imaging and is well suited for detection of light elements imbedded in metallic containers. Thus, Neutron Imaging (NI) is investigated as a tool for the detection of pore structure of hydrated wellbore cement. Recent measurements were conducted at the Oak Ridge National Laboratory (ORNL) High Flux Isotope Reactor (HFIR) neutron imaging facility. NI is is highly sensitive to light elements such as Hydrogen (H). Oil well cements that have undergone a full hydration contain on average 30%-40% of free water in its pore structure. The unreacted water is the main

  1. Microbial analysis of biofilms on cement surfaces: An investigation in cement-associated peri-implantitis.

    Science.gov (United States)

    Korsch, Michael; Walther, Winfried; Marten, Silke-Mareike; Obst, Ursula

    2014-09-05

    The cementation of implant-supported restorations always poses the risk of excess cement retained in the peri-implant sulcus despite careful clinical control. Excess cement can become the basis of colonization by oral microorganisms. As a result of the biofilm formation peri-mucositis or peri-implantitis may develop. Complications were observed in the routine prosthetic restoration of implants when a methacrylate-based cement was used. These developed a few weeks after cementation of the suprastructure and caused bleeding on probing as well as suppuration from the peri-implant tissue. In the revision therapy, excess cement in the peri-implant sulcus was found in many cases. This excess cement was sampled from ten patients and investigated for biofilm formation. For this purpose, the cement samples were collected and analyzed for bacterial in situ colonization by 16S rDNA-based methods. In laboratory experiments, the methacrylate-based cement and two other dental cements were then investigated for their proneness to form biofilm. The results of the in situ and in vitro investigations revealed a strong tendency towards bacterial invasion of the methacrylate-based cement by opportunistic species and pathogens.

  2. Design and analysis of a cogeneration plant using heat recovery of a cement factory

    OpenAIRE

    2015-01-01

    There is a more potential in a cement factory for electric power generation using waste heat recovery compared to the other industries. A case study has been done at a cement factory having two units, 1600 TPD and 5500 TPD, identified three waste heat rejections at 176 °C, 330 °C and 420 °C and designed a suitable power plant configuration. In this work, an attempt has been made to quantify the power generation capacity with plant analysis. It has been resulted that 12.5 MW of power can be pr...

  3. The influence of cement type and temperature on chloride binding in cement paste

    DEFF Research Database (Denmark)

    Jensen, Ole Mejlhede; Korzen, Migge Sofie Hoffmann; Skibsted, Jørgen

    1998-01-01

    This paper describes effects of cement type and temperature on chloride binding in cement paste, which is an important subject in relation to life-time modelling of reinforced concrete structures. The influence of cement type on chloride binding is investigated by substituting cement with pure...... cement clinker. Both theoretical considerations and experimental data for chloride binding in cement pastes are presented. A physico-chemically based model to describe the influence of temperature on physical binding of chloride is presented. Solid-state 27Al and 29Si magic-angle spinning (MAS) nuclear...... magnetic resonance (NMR) spectroscopy has been used for quantification of the anhydrous and hydrated aluminate and silicate phases in the chloride exposed cement pastes. The 27Al isotropic chemical shift and nuclear quadrupole coupling is reported for a synthetic sample of Friedel's salt, Ca2Al(OH)6Cl×2H2O....

  4. Industrial coal utilization

    Energy Technology Data Exchange (ETDEWEB)

    None

    1979-01-01

    The effects of the National Energy Act on the use of coal in US industrial and utility power plants are considered. Innovative methods of using coal in an environmentally acceptable way are discussed: furnace types, fluidized-bed combustion, coal-oil-mixtures, coal firing in kilns and combustion of synthetic gas and liquid fuels. Fuel use in various industries is discussed with trends brought about by uncertain availability and price of natural gas and fuel oils: steel, chemical, cement, pulp and paper, glass and bricks. The symposium on Industrial Coal Utilization was sponsored by the US DOE, Pittsburgh Energy Technology Center, April 3 to 4, 1979. Twenty-one papers have been entered individually into the EDB. (LTN)

  5. A note on cement in asteroids

    Science.gov (United States)

    Bilalbegović, G.

    2016-09-01

    Cement mineral tobermorite was formed in hydrothermal experiments on alternation of calcium-aluminum-rich inclusions (CAIs) in carbonaceous chondrite meteorites. Unidentified bands at 14 μm were measured for CAIs and the matrix of the Allende meteorite sample, as well as for Hektor and Agamemnon asteroids. The presence of cement nanoparticles may explain the feature at 14 μm.

  6. Investigation of a Hardened Cement Paste Grout

    DEFF Research Database (Denmark)

    Esteves, Luis Pedro; Sørensen, Eigil Verner

    This report documents a series of tests performed on a hardened cement paste grout delivered by the client, Det Norske Veritas A/S.......This report documents a series of tests performed on a hardened cement paste grout delivered by the client, Det Norske Veritas A/S....

  7. Chloride ingress in cement paste and mortar

    DEFF Research Database (Denmark)

    Jensen, Ole Mejlhede; Hansen, Per Freiesleben; Coats, Alison M.

    1999-01-01

    In this paper chloride ingress in cement paste and mortar is followed by electron probe microanalysis. The influence of several paste and exposure parameters on chloride ingress are examined (e.g., water-cement ratio, silica fume addition, exposure time, and temperature), The measurements...

  8. A note on cement in asteroids

    CERN Document Server

    Bilalbegovic, G

    2016-01-01

    Cement mineral tobermorite was formed in hydrothermal experiments on alternation of calcium-aluminum-rich inclusions (CAIs) in carbonaceous chondrite meteorites. Unidentified bands at 14 microns were measured for CAIs and the matrix of the Allende meteorite sample, as well as for Hektor and Agamemnon asteroids. The presence of cement nanoparticles may explain the feature at 14 microns.

  9. Effect of hydrogen sulfide emissions on cement mortar specimens

    Energy Technology Data Exchange (ETDEWEB)

    Idriss, A. F. [Alberta Environment, Science and Technology Branch, Edmonton, AB (Canada); Negi, S. C.; Jofriet, J. C.; Haywoard, G. L. [Guelph Univ., Guelph, ON (Canada)

    2001-07-01

    Six different cement mortar specimens used in animal buildings, where they were exposed to hydrogen sulfide generated from anaerobic fermentation of manure during a period of one year, were investigated. Primary interest was on comparing the corrosion resistance of different cement mortar specimens under long term exposure to hydrogen sulfide. The impressed voltage technique was used to test the specimens in the laboratory. Results revealed that test specimens made with eight per cent silica fume cement replacement performed best and similar Portland cement mortar specimens with a water-cement ratio of 0.55 (PC55) the poorest. All other treatments, (Portland cement with a water to cement ratio of 045, Portland cement Type 50, Portland cement with fibre mesh and Portland cement Type 10 coated with linseed oil) all with water-cement ratios of 0.45, were less effective in preventing corrosion than silica fume replacement.

  10. Shrinkage Properties of Cement Stabilized Gravel

    DEFF Research Database (Denmark)

    Lund, Mia Schou Møller; Hansen, Kurt Kielsgaard

    2014-01-01

    Cement stabilized gravel is an attractive material in road construction because its strength prop-erties are accommodating the increasingly higher requirements to the bearing capacity of a base course. However, reflection cracking of cement stabilized gravel is a major concern. In this pa......-per the shrinkage properties of cement stabilized gravel have been documented under various temperature and relative humidity conditions. Two cement contents corresponding to a 28-days compressive strength of 6.2 MPa and 12.3 MPa have been tested and compared. It is found that the coefficient of linear expansion...... for the two cement contents is 9.9 × 10-6 ⁰C-1 and 11.3 × 10-6 ⁰C-1, respectively. Furthermore, it is found that reflecting cracking can mainly be explained by temperature dependent shrinkage rather than moisture dependent shrinkage....

  11. Energetically Modified Cement (EMC) - Performance Mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Ronin, Vladimir; Elfgren, Lennart [Luleaa Univ. of Technology (Sweden). Centre for High Performance Cement

    2003-03-01

    Energetically Modified Cements, EMC, made of intensively milled cement (50%) and fillers (50%) of quartz or fly ash have been compared to blends of Ordinary Portland Cement, OPC, and fillers. The EMCs have better properties than other blends and are comparable to unblended OPC. This remarkable fact can probably be explained as follows. The grinding process reduces the size of both cement grains and fillers. This combined with the creation of micro defects gives the ground cement a very high degree of hydration. The increased early hydration and a better distribution of hydration products results in an extensive pore size refinement of the hardened binder. This pore size refinement leads to a favorably reduced permeability and diffusivity and very good mechanical properties.

  12. Trends of coal industry in the European Union; Tendencias del Sector del Carbon en la Union Europea

    Energy Technology Data Exchange (ETDEWEB)

    Sierra Lopez, J.; Luque Cabal, V. [Direccion General de la Energia, Comision Europea (Spain)

    1995-12-31

    The main trend in coal consumption in the European Union is its increasing dependence on electricity generation. Coal has to be assessed and defended within the global energy context as a fuel which should remain as a realistic and competitive option for decision makers. Coal has to be assessed and defended within the global energy context as a fuel which should remain as a realistic and competitive option for decision makers. Coal can more than adequately contribute to the economic competitiveness of the European Union and to security of energy supplies. But public concern about the environment, as well as the question of the size of the initial capital expenditure and the returns on financial investment, currently favour gas. The paper also presents, the main trends in the supply of coal in the producing countries of the Union, focusing particular attention on Spain. (Author)

  13. Proceedings of the Third CANMET/ACI International Symposium on Sustainable Development of Cement and Concrete : volume 1 and supplementary papers

    Energy Technology Data Exchange (ETDEWEB)

    Malhotra, V.M. (ed.) [Natural Resources Canada, Ottawa, ON (Canada). CANMET Energy Technology Centre

    2001-07-01

    This conference brought together representatives from industry, universities, and government agencies from around the world to discuss the recent trend of sustainable development in the cement and concrete industry. The presentations focused on all aspects of concrete technology and sustainability with most of them dealing with the issue of supplementing cementing materials with admixtures such as fly ash in an effort to reduce carbon dioxide emissions. In addition to the referenced proceedings, a book of supplementary papers was also published. The papers focused mainly on the use of fly ash from coal-based power generation, slags from blast-furnaces and silica fumes. It was emphasized that the negative environmental effects of current cement/concrete production can be reduced substantially by using cement blends with minimum portland cement and maximum pozzolanic loading. In addition to extending the longevity of concrete, such cement blends also avoid the huge cost of repairs and replacement cycles. Market forces will drive this transition toward sustainable development in the concrete and cement industry. The economic and environmental advantages of improving the quality of the concrete are great. A total of 63 papers were presented at this conference, of which 31 have been processed separately for inclusion in the database. refs., tabs., figs.

  14. The incorporation of wood waste ash as a partial cement replacement material for making structural grade concrete: An overview

    OpenAIRE

    2015-01-01

    With increasing industrialization, the industrial byproducts (wastes) are being accumulated to a large extent, leading to environmental and economic concerns related to their disposal (land filling). Wood ash is the residue produced from the incineration of wood and its products (chips, saw dust, bark) for power generation or other uses. Cement is an energy extensive industrial commodity and leads to the emission of a vast amount of greenhouse gases, forcing researchers to look for an alterna...

  15. Pack cementation coatings for alloys

    Energy Technology Data Exchange (ETDEWEB)

    He, Yi-Rong; Zheng, Minhui; Rapp, R.A. [Ohio State Univ., Columbus, OH (United States)

    1996-08-01

    The halide-activated pack cementation process was modified to produce a Ge-doped silicide diffusion coating on a Cr-Cr{sub 2}Nb alloy in a single processing step. The morphology and composition of the coating depended both on the composition of the pack and on the composition and microstructure of the substrate. Higher Ge content in the pack suppressed the formation of CrSi{sub 2} and reduced the growth kinetics of the coating. Ge was not homogeneously distributed in the coatings. In cyclic and isothermal oxidation in air at 700 and 1050{degrees}C, the Ge-doped silicide coating protected the Cr-Nb alloys from significant oxidation by the formation of a Ge-doped silica film. The codeposition and diffusion of aluminum and chromium into low alloy steel have been achieved using elemental Al and Cr powders and a two-step pack cementation process. Sequential process treatments at 925{degrees}C and 1150{degrees}C yield dense and uniform ferrite coatings, whose compositions are close to either Fe{sub 3}Al or else FeAl plus a lower Cr content, when processed under different conditions. The higher content of Al in the coatings was predicted by thermodynamic calculations of equilibrium in the gas phase. The effect of the particle size of the metal powders on the surface composition of the coating has been studied for various combinations of Al and Cr powders.

  16. Cements with low Clinker Content

    Science.gov (United States)

    García-Lodeiro, I.; Fernández-Jiménez, A.; Palomo, A.

    2015-11-01

    Hybrid alkaline cements are multi-component systems containing a high percentage of mineral additions (fly ash, blast furnace slag), low proportions (clinker and scarce amounts of alkaline activators. The substantially lower amount of clinker needed to manufacture these binders in comparison to ordinary Portland cement is both economically and ecologically beneficial. Their enormous versatility in terms of the raw materials used has made them the object of considerable interest. The present study explored the mechanical strength of binary blends mixes; B1= 20% clinker (CK) + 80% fly ash (FA) and B2=20% clinker + 80% blast furnace slag (BFS), both hydrated in the presence and absence of an alkaline activator specifically designed for this purpose. The use of the activator enhanced the development of early age strength considerably. All the hydrated matrices were characterised with XRD, SEM/EDX and (29Si and 27Al) NMR. The use of the alkaline activator generated reaction products consisting primarily of a mix of gels ((N,C)-A-S-H and C-A-S-H) whose respective proportions were found to depend upon system composition and initial reactivity.

  17. Influence of the method of blending an antibiotic powder with an acrylic bone cement powder on physical, mechanical, and thermal properties of the cured cement.

    Science.gov (United States)

    Lewis, Gladius; Janna, Si; Bhattaram, Anuradha

    2005-07-01

    Two variants of antibiotic powder-loaded acrylic bone cements (APLBCs) are widely used in primary total joint replacements. In the United States, the antibiotic is manually blended with the powder of the cement at the start of the procedure, while, in Europe, pre-packaged commercially-available APLBCs (in which the blending is carried out using an industrial mixer) are used. Our objective was to investigate the influence of the method of blending gentamicin sulphate with the powder of the Cemex XL formulation on a wide collection of properties of the cured cement. The blending methods used were manual mixing (the MANUAL Set), use of a small-scale, easy-to-use, commercially-available mechanical powder mixer, OmoMix 1 (the MECHANICAL Set), and use of a large-scale industrial mixer (Cemex Genta) [the INDUSTRIAL Set]. In the MECHANICAL and MANUAL Sets, the blending time was 3 min. In preparing the test specimens for each set, the blended powder used contained 4.22 wt% of the gentamicin powder. The properties determined were the strength, modulus, and work-to-fracture (all obtained under four-point bending), plane-strain fracture toughness, Weibull mean fatigue life (fatigue conditions: +/-15 MPa; 2 Hz), activation energy and frequency factor for the cement polymerization process (both determined using differential scanning calorimetry, at heating rates of 5, 10, 15, and 20 Kmin(-1)), the diffusion coefficient for the absorption of phosphate buffered saline, PBS, at 37 degrees C, and the rate of elution of the gentamicin into PBS, at 37 degrees C (E). Also determined were the particle size, particle size distribution, and morphology of the blended powders and of the gentamicin. For each of the cured cement properties (except for E), there is no statistically significant difference between the means for the 3 cements, a finding that parallels the observation that there are no significant differences in either the mean particle size or the morphology of the blended cement

  18. On the Fresh/Hardened Properties of Cement Composites Incorporating Rubber Particles from Recycled Tires

    Directory of Open Access Journals (Sweden)

    Alessandra Fiore

    2014-01-01

    Full Text Available This study investigates the ameliorative effects on some properties of cement-based materials which can be obtained by incorporating rubber particles as part of the fine aggregates. The aim is to find out optimal cement composite/mortar mixtures, containing recycled-tyre rubber particles, suitable for specific engineering applications. Different percentages of rubber particles, from 0% to 75%, were used and, for each percentage, the suitable amount of sand was investigated in order to achieve the best fresh/hardened performances. In particular the following characteristics were examined: density, compressive strength, modulus of elasticity, shrinkage, weight loss, flexural behaviour, thermal conductivity, rapid freezing and thawing durability, and chloride permeability. The experimental results were compared with the ones of cement composite specimens without rubber aggregates. Test results show that the proposed rubberized mortar mixes are particularly suitable for some industrial and architectural applications, such as under-rail bearings, road constructions, paving slabs, false facades, and stone backing.

  19. Cement compositions for cementing wells, allowing pressure gas-channeling in the cemented annulus to be controlled

    Energy Technology Data Exchange (ETDEWEB)

    Parcevaux, P.A.; Piot, B.M.; Vercaemer, C.J.

    1987-01-27

    The invention relates to cement compositions for cementing oil and geothermal wells. These compositions allow pressure gas-channeling to be effectively controlled up to more than about 485/sup 0/F. The compositions according to the invention comprise four essential constituents: a cement, a styrene-butadiene latex, a latex stabilizer, and water. The cement is a hydraulic cement belonging to any class among those currently used for cementing oil wells. The useful stabilizers according to the invention are anionic polyelectrolytes such as lignosulfanates and their desulfonated and/or resulfonated derivatives; sulfonated lignin-Kraft products; melamine-formaldehyde resins modified by a sulfonic acid or sulfite; formaldehyde/sulfonated naphthalene resins; or the condensation products of bi-nuclear sulfonated phenols and of formaldehyde. Preferred are the sodium salts of the condensation product of mononaphthalenesulfonic acid and of formaldehyde. The patent also includes a description of tests of various cement compositions of the invention, plus scanning electron microscope observations. 10 figs., 7 tabs.

  20. Use of MRF residue as alternative fuel in cement production.

    Science.gov (United States)

    Fyffe, John R; Breckel, Alex C; Townsend, Aaron K; Webber, Michael E

    2016-01-01

    Single-stream recycling has helped divert millions of metric tons of waste from landfills in the U.S., where recycling rates for municipal solid waste are currently over 30%. However, material recovery facilities (MRFs) that sort the municipal recycled streams do not recover 100% of the incoming material. Consequently, they landfill between 5% and 15% of total processed material as residue. This residue is primarily composed of high-energy-content non-recycled plastics and fiber. One possible end-of-life solution for these energy-dense materials is to process the residue into Solid Recovered Fuel (SRF) that can be used as an alternative energy resource capable of replacing or supplementing fuel resources such as coal, natural gas, petroleum coke, or biomass in many industrial and power production processes. This report addresses the energetic and environmental benefits and trade-offs of converting non-recycled post-consumer plastics and fiber derived from MRF residue streams into SRF for use in a cement kiln. An experimental test burn of 118 Mg of SRF in the precalciner portion of the cement kiln was conducted. The SRF was a blend of 60% MRF residue and 40% post-industrial waste products producing an estimated 60% plastic and 40% fibrous material mixture. The SRF was fed into the kiln at 0.9 Mg/h for 24h and then 1.8 Mg/h for the following 48 h. The emissions data recorded in the experimental test burn were used to perform the life-cycle analysis portion of this study. The analysis included the following steps: transportation, landfill, processing and fuel combustion at the cement kiln. The energy use and emissions at each step is tracked for the two cases: (1) The Reference Case, where MRF residue is disposed of in a landfill and the cement kiln uses coal as its fuel source, and (2) The SRF Case, in which MRF residue is processed into SRF and used to offset some portion of coal use at the cement kiln. The experimental test burn and accompanying analysis indicate

  1. Combustion of large solid fuels in cement rotary kilns

    Energy Technology Data Exchange (ETDEWEB)

    Nielsen, Anders Rooma

    2012-03-15

    The cement industry has a significant interest in replacing fossil fuels with alternative fuels in order to minimize production costs and reduce CO{sub 2} emissions. These new alternative fuels are in particular solid fuels such as refuse derived fuel (RDF), tire-derived fuel (TDF), meat and bone meal (MBM), waste wood, sewage sludge, paper and plastics. This thesis provides an insight into the utilization of solid alternative fuels in the material inlet end of rotary kilns. This position is interesting because it allows utilization of large fuel particles, thereby eliminating the need for an expensive shredding of the fuels. The challenge, however, is that the solid fuels will be mixed into the cement raw materials, which is likely to affect process stability and clinker quality, as described above. The mixing of fuels and raw materials was studied experimentally in a pilot-scale rotary drum and was found to be a fast process, reaching steady state within few drum revolutions. Thus, heat transfer by conduction from the cement raw materials to the fuel particles is a major heat transfer mechanism rather than convection or radiation from the freeboard gas above the material bed. Consequently, the temperature of the cement raw materials becomes a factor of great importance for heating the fuel particles. Combustion of different alternative fuels has been investigated experimentally in a pilot-scale rotary furnace under conditions similar to those in the material inlet end of cement rotary kilns. The main focus was on tire rubber and pine wood which are relevant fuels in this context. Heating, drying and devolatilization of alternative fuels are fast processes that primarily depend on heat transfer and fuel particle size. Devolatilization of a large wood or tire particle with a thickness of 20 mm at 900 deg. C is for example around 2 minutes. By contrast, char oxidation is a slow process which may greatly reduce the amounts of solid fuels to be utilized in the

  2. Effect of Selected Alternative Fuels and Raw Materials on the Cement Clinker Quality

    Science.gov (United States)

    Strigáč, Július

    2015-11-01

    The article deals with the study of the effects of alternative fuels and raw materials on the cement clinker quality. The clinker quality was expressed by the content of two principal minerals alite C3S and belite C2S. The additions of alternative fuels ashes and raw materials, in principle, always increased the belite content and conversely reduced the amount of alite. The alternative fuels with high ash content were used such as the meat-bone meal, sewage sludge from sewage treatment plants and paper sludge and the used alternative raw materials were metallurgical slags - granulated blastfurnace slag, air cooled blastfurnace slag and demetallized steel slag, fluidized bed combustion fly ash and waste glass. Meat-bone meal, sewage sludge from sewage treatment plants and paper sludge were evaluated as moderately suitable alternative fuels which can be added in the amounts of 2.8 wt. % addition of meat-bone meals ash, 3.64 wt. % addition of sewage sludge ash and 3.8 wt. % addition of paper sludge ash to the cement raw mixture. Demetallised steel slag is suitable for production of special sulphate resistant cement clinker for CEM I -SR cement with addition up to 5 wt. %. Granulated blastfurnace slag is a suitable alternative raw material with addition 4 wt. %. Air cooled blastfurnace slag is a suitable alternative raw material with addition 4.2 wt. %. Waste glass is not very appropriate alternative raw material with addition only 1.16 wt. %. Fluidized bed combustion fly ash appears not to be equally appropriate alternative raw material for cement clinker burning with less potential utilization in the cement industry and with addition 3.41 wt. %, which forms undesired anhydrite CaSO4 in the cement clinker.

  3. Effect of Selected Alternative Fuels and Raw Materials on the Cement Clinker Quality

    Directory of Open Access Journals (Sweden)

    Strigáč Július

    2015-11-01

    Full Text Available The article deals with the study of the effects of alternative fuels and raw materials on the cement clinker quality. The clinker quality was expressed by the content of two principal minerals alite C3S and belite C2S. The additions of alternative fuels ashes and raw materials, in principle, always increased the belite content and conversely reduced the amount of alite. The alternative fuels with high ash content were used such as the meat-bone meal, sewage sludge from sewage treatment plants and paper sludge and the used alternative raw materials were metallurgical slags - granulated blastfurnace slag, air cooled blastfurnace slag and demetallized steel slag, fluidized bed combustion fly ash and waste glass. Meat-bone meal, sewage sludge from sewage treatment plants and paper sludge were evaluated as moderately suitable alternative fuels which can be added in the amounts of 2.8 wt. % addition of meat-bone meals ash, 3.64 wt. % addition of sewage sludge ash and 3.8 wt. % addition of paper sludge ash to the cement raw mixture. Demetallised steel slag is suitable for production of special sulphate resistant cement clinker for CEM I –SR cement with addition up to 5 wt. %. Granulated blastfurnace slag is a suitable alternative raw material with addition 4 wt. %. Air cooled blastfurnace slag is a suitable alternative raw material with addition 4.2 wt. %. Waste glass is not very appropriate alternative raw material with addition only 1.16 wt. %. Fluidized bed combustion fly ash appears not to be equally appropriate alternative raw material for cement clinker burning with less potential utilization in the cement industry and with addition 3.41 wt. %, which forms undesired anhydrite CaSO4 in the cement clinker.

  4. Through Lean Manufacturing Techniques Improvement InProduction of Cement Plant

    Directory of Open Access Journals (Sweden)

    Udai Singh Chouhan

    2016-07-01

    Full Text Available The production of cement is a process industry which is distinct from manufacturing and the main objective here is to apply lean manufacturing technique to the eradicate waste to the processes and parameters which are common between process and discrete manufacturing. Lean signifies a major advance over traditional mass production methods. Value stream mapping is used first to identify different waste present in the current state. This paper will describe work undertaken investigating the application of lean thinking to a continuous production environment, in this instance exemplified by the cement industry. Implementation of lean helps many organizations to improve their productivity and efficiency Cement plays a vital role in economic development of any country. Having more than a hundred and fifty years history, it has been used extensively in construction of anything, from a small building to a mammoth multi-purpose project. The need for improving the efficiency of the cement production line is widely acknowledged in order to reduce the downtime rates, and satisfy high levels of market demand where the demand for cement is mostly second substance behind water. This paper articulates a methodology for data collection, knowledge extraction, model creation and experimentation that combines the use of process mapping, computational simulation. A detailed description of each step of the process is given and is illustrated by results from a case study undertaken during the research. This paper describes work undertaken to implement lean practices in the continuous process sector as represented by cement production. One of the major barriers to lean implementation is providing evidence of its potential benefit to end-users. This work aims to overcome this obstacle by producing a tool which can be used to easily visualize the benefits of adopting lean practices without requiring disruption to the production environment

  5. Dehydration kinetics of Portland cement paste at high temperature

    NARCIS (Netherlands)

    Zhang, Q.; Ye, G.

    2012-01-01

    Portland cement paste is a multiphase compound mainly consisting of calcium-silicate-hydrate (CSH) gel, calcium hydroxide (CH) crystal, and unhydrated cement core. When cement paste is exposed to high temperature, the dehydration of cement paste leads to not only the decline in strength, but also th

  6. SOME EVOLUTIONARY TENDENCIES OF NEOTROPICAL PRIMATES: Algunas tendencias evolutivas de los primates neotropicales

    Directory of Open Access Journals (Sweden)

    THOMAS R. DEFLER

    Full Text Available La evolución de los primates neotropicales ha transcurrido aislada o de forma independiente a la de otros primates del mundo, porque poseen una historia evolutiva diferente. Hay varias características de los primates neotropicales (Platirrinos que son bien distintas a las del viejo mundo (Catarrinos, incluyendo la fórmula dental, el arreglo de las placas craneales, la anatomía del aparato auditivo, pesos corporales menores, una menor adaptación a comportamientos terrestres, algunos poseen colas prensiles y baja diferenciación fenotípica. Formas monógamas de platirrinos comparten una tendencia de evolución cromosómica rápida con un grupo monógamo de Catarrinos (los Hilobátidos o gibones. La historia filogenética de platirrinos, contrasta con la de catarrinos debido a una división filética antigua (mioceno de los primates del nuevo mundo en dos grupos, con características filogenéticas expresadas en las especies actuales. En contraste, la diferenciación de catarrinos con características que se pueden identificar en especies actuales no sucedió sino hasta el Plio-Pleistoceno. Algunas de estas tendencias, pueden ser explicadas hipotéticamente teniendo en cuenta las características ecológicas planteadas en el nuevo continente; otras tendencias tal vez son el resultado de caminos evolutivos tomados al azar durante la evolución del grupo o, como resultado tanto de deriva genética como de un efecto fundador. Sin embargo, queda mucho trabajo para reconocer la totalidad de las singularidades de los platirrinos y poder apreciar los detalles de su evolución.The evolution of neotropical primates has occurred isolated from other primates of the world, resulting in a distinct evolutionary history. Various characteristics of neotropical primates (Platyrrhini are quite distinct from those of the Old World (Catarrhini, including the dental formula, the position of cranial plates, the anatomy of the auditory apparatus, much less average

  7. Tendencias de mortalidad por cánceres atribuibles al tabaco en México

    Directory of Open Access Journals (Sweden)

    Tovar-Guzmán Víctor José

    2002-01-01

    Full Text Available Objetivo. Describir la tendencia de la mortalidad por cáncer atribuible al consumo de tabaco, particularmente neoplasias del pulmón, en México, durante el periodo 1980-1997. Material y métodos. Se hizo un análisis de tendencias de mortalidad para cada tipo de cáncer asociado con el tabaco, según la Clasificación Internacional de Enfermedades. Las tasas cruda y ajustada de mortalidad fueron estimadas en términos de edad, género, causa básica de la muerte y año, entre 1980 y 1997. Se estimó la razón de género y proporción relativa para los casos que estaban en el grupo de edad entre 35 y 64 años y para toda la población estudiada. Como denominador se utilizaron las proyecciones por edad calculadas por el Consejo Nacional de Población (1970-2010. Resultados. La razón de género para las tasas de mortalidad por cáncer de laringe, esófago, cavidad oral y faringe fue de 2.10:1.00 (hombre: mujer. La razón de género para el cáncer de laringe es enorme: 4.21: 1.00, probablemente debida a la mayor prevalencia de hombres fumadores de tabaco. La proporción relativa estimada, usando la mortalidad total debida a tumores malignos, entre 1980 y 1997 fue la siguiente: cáncer de pulmón 12.31%, laringe 1.71%, esófago 1.55% y cavidad oral/faringe 1.49%. El antecedente de tabaquismo tiene correlación con la tendencia de la tasa de mortalidad por cáncer del pulmón (Beta: 0.910, IC 95%: 1.097-1.797; R² 0.827. Para los grupos sociales mas pobres, por entidad federativa, la correlación está invertida (Beta: -0.510, IC 95%: -0.170, -0.039, R²: 0.260. Conclusiones. En México, la mejoría en el diagnóstico, la transición demográfica y el incremento del consumo de tabaco son, probablemente, los principales factores a los que se atribuye la tasa de mortalidad por cáncer. No obstante, otras variables asociadas con el estilo de vida, como urbanización, actividad física, ingesta de carotenoides y otros componentes dietéticos y t

  8. RECYCLED WASTE-BASED CEMENT COMPOSITE PATCH MATERIALS FOR RAPID/PERMANENT ROAD RESTORATION.

    Energy Technology Data Exchange (ETDEWEB)

    SUGAMA,T.

    2001-07-31

    Over the past year, KeySpan Energy sponsored a research program at Brookhaven National Laboratory (BNL) aimed at recycling boiler ash (BA) and waste water treatment sludge (WWTS) byproducts generated from Keyspan's power stations into potentially useful materials, and at reducing concurrent costs for their disposal. Also, KeySpan has an interest in developing strategies to explicitly integrate industrial ecology and green chemistry. From our collaborative efforts with Keyspan (Diane Blankenhom Project Manager, and Kenneth Yager), we succeeded in recycling them into two viable products; Pb-exchange adsorbents (PEAs), and high-performance cements (HpCs). These products were made from chemically bonded cement and ceramic (CBC) materials that were synthesized through two-step chemical reaction pathways, acid-base and hydration. Using this synthesis technology, both the WWTS and BA served in acting as solid base reactants, and sodium polyphosphate, [-(-NaPO{sub 3}-)-{sub n}], known as an intermediator of fertilizer, was employed as the acid solution reactant. In addition, two commercial cement additives, Secar No. 51 calcium aluminate cement (CAC) and Type I calcium silicate cement (CSC), were used to improve mechanical behavior and to promote the rate of acid-base reaction of the CBC materials.

  9. Recycling of porcelain tile polishing residue in portland cement: hydration efficiency.

    Science.gov (United States)

    Pelisser, Fernando; Steiner, Luiz Renato; Bernardin, Adriano Michael

    2012-02-21

    Ceramic tiles are widely used by the construction industry, and the manufacturing process of ceramic tiles generates as a major residue mud derived from the polishing step. This residue is too impure to be reused in the ceramic process and is usually discarded as waste in landfills. But the analysis of the particle size and concentration of silica of this residue shows a potential use in the manufacture of building materials based on portland cement. Tests were conducted on cement pastes and mortars using the addition of 10% and 20% (mass) of the residue. The results of compressive strength in mortars made up to 56 days showed a significant increase in compressive strength greater than 50%. The result of thermogravimetry shows that portlandite is consumed by the cement formed by the silica present in the residue in order to form calcium silicate hydrate and featuring a pozzolanic reaction. This effect improves the performance of cement, contributes to research and application of supplementary cementitious materials, and optimizes the use of portland cement, reducing the environmental impacts of carbon dioxide emissions from its production.

  10. Studies on the reuse of waste printed circuit board as an additive for cement mortar.

    Science.gov (United States)

    Ban, Bong-Chan; Song, Jong-Yoon; Lim, Joong-Yeon; Wang, Soo-Kyoon; An, Kwang-Guk; Kim, Dong-Su

    2005-01-01

    The recent development in electronic industries has generated a drastic increase in production of printed circuit boards (PCB). Accordingly, the amount of waste PCB from electronic productions and waste electronics and its environmental impact such as soil and groundwater contamination have become a great concern. This study aims to propose a method for reuse of waste PCB as an additive for cement mortar. Although the expansibility of waste PCB powder finer than 0.08 mm in water was observed to be greater than 2.0%, the maximum expansion rates in water for 0.08 to approximately 0.15 and 0.15 to approximately 0.30 mm sized PCB powders were less than 2.0%, which satisfied the necessary condition as an alternative additive for cement mortar in place of sand. The difference in the compressive strength of standard mortar and waste PCB added mortar was observed to be less than 10% and their difference was expected to be smaller after prolonged aging. The durability of waste PCB added cement mortar was also examined through dry/wet conditioning cyclic tests and acidic/alkaline conditioning tests. From the tests, both weight and compressive strength of cement mortar were observed to be recovered with aging. The leaching test for heavy metals from waste PCB added mortar showed that no heavy metal ions such as copper, lead, or cadmium were detected in the leachate, which resulted from fixation effect of the cement hydrates.

  11. Ecophysiological and ultrastructural effects of dust pollution in lichens exposed around a cement plant (SW Slovakia).

    Science.gov (United States)

    Paoli, Luca; Guttová, Anna; Grassi, Alice; Lackovičová, Anna; Senko, Dušan; Sorbo, Sergio; Basile, Adriana; Loppi, Stefano

    2015-10-01

    The study investigated the ecophysiological and ultrastructural effects of dust pollution from a cement industry in the lichen species Evernia prunastri and Xanthoria parietina, which were exposed for 30, 90 and 180 days around a cement mill, two quarries, and inhabited and agricultural sites in SW Slovakia. The results showed that dust deposition from quarrying activities and cement works at the cement mill (mainly enriched in Ca, Fe and Ti) significantly affected the photosynthetic apparatus of E. prunastri (sensitive to dust and habitat eutrophication), while X. parietina (tolerant to dust and habitat eutrophication) adapted to the new environment. The length of the exposure strongly affected the vitality of the mycobiont (measured as dehydrogenase activity) in transplanted lichens. Dust deposition led to ultrastructural alterations, including lipid droplets increase, swelling of cellular components, thylakoid degeneration and sometimes plasmolysis, which, on the whole, gave the cells an aged appearance. Photosynthetic parameters deserve further attention as potential indicators for monitoring early biological symptoms of the air pollution caused during cement production.

  12. Chloride adsorption by calcined layered double hydroxides in hardened Portland cement paste

    KAUST Repository

    Yoon, Seyoon

    2014-06-01

    This study investigated the feasibility of using calcined layered double hydroxides (CLDHs) to prevent chloride-induced deterioration in reinforced concrete. CLDHs not only adsorbed chloride ions in aqueous solution with a memory effect but also had a much higher binding capacity than the original layered double hydroxides (LDHs) in the cement matrix. We investigated this adsorption in hardened cement paste in batch cultures to determine adsorption isotherms. The measured and theoretical binding capacities (153 mg g -1 and 257 mg g-1, respectively) of the CLDHs were comparable to the theoretical capacity of Friedel\\'s salt (2 mol mol-1 or 121 mg g-1), which belongs to the LDH family among cementitious phases. We simulated chloride adsorption by CLDHs through the cement matrix using the Fickian model and compared the simulation result to the X-ray fluorescence (XRF) chlorine map. Based on our results, it is proposed that the adsorption process is governed by the chloride transport through the cement matrix; this process differs from that in an aqueous solution. X-ray diffraction (XRD) analysis showed that the CLDH rebuilds the layered structure in a cementitious environment, thereby demonstrating the feasibility of applying CLDHs to the cement and concrete industries. © 2014 Published by Elsevier B.V. All rights reserved.

  13. Effect of blastfurnace slag addition to Portland cement for cationic exchange resins encapsulation

    Directory of Open Access Journals (Sweden)

    Stefan L.

    2013-07-01

    Full Text Available In the nuclear industry, cement-based materials are extensively used to encapsulate spent ion exchange resins (IERs before their final disposal in a repository. It is well known that the cement has to be carefully selected to prevent any deleterious expansion of the solidified waste form, but the reasons for this possible expansion are not clearly established. This work aims at filling the gap. The swelling pressure of IERs is first investigated as a function of ions exchange and ionic strength. It is shown that pressures of a few tenths of MPa can be produced by decreases in the ionic strength of the bulk solution, or by ion exchanges (2Na+ instead of Ca2+, Na+ instead of K+. Then, the chemical evolution of cationic resins initially in the Na+ form is characterized in CEM I (Portland cement and CEM III (Portland cement + blastfurnace slag cements at early age and an explanation is proposed for the better stability of CEM III material.

  14. Dermatoses in cement workers in southern Taiwan.

    Science.gov (United States)

    Guo, Y L; Wang, B J; Yeh, K C; Wang, J C; Kao, H H; Wang, M T; Shih, H C; Chen, C J

    1999-01-01

    Construction workers are known to have occupational dermatoses. The prevalence of such dermatoses was unknown in Taiwanese construction workers. The objective of this study was to determine the work exposure, prevalence of skin manifestations, and sensitivity to common contact allergens in cement workers of southern Taiwan. A total of 1147 current regular cement workers were telephone-interviewed about skin problems during the past 12 months, work exposure, and personal protection. Among those interviewed, 166 were examined and patch tested with common contact allergens. A high % of cement workers reported skin problems in the past 12 months. More men (13.9%) reported skin problems possibly related to work than women (5.4%). Prevalence was associated with lower use of gloves, duration of work as cement worker, and more time in jobs involving direct manual handling of cement, especially tiling. A high % of dermatitis was noted in the 166 workers examined, which correlated with reported skin problems. On patch testing, construction workers had a high frequency of sensitivity to chromate. Sensitivity to chromate or cobalt was associated with reported skin problems, or dorsal hand dermatitis on examination. These workers' dermatitis was under-diagnosed and inadequately managed. It is concluded that cement workers in southern Taiwan had a high prevalence of skin problems related to cement use. Protective measures, work practice, and physician education should be improved to prevent or manage such problems.

  15. International development trends in low-energy cements

    Energy Technology Data Exchange (ETDEWEB)

    Stark, J.; Mueller, A.

    1988-04-01

    Besides the currently dominant tendency to increase the proportion of interground additive in cement, the following development trends are internationally emerging in the material composition of so-called low-energy cements with a view to minimizing energy input for cement manufacture: (1) active belite cement with the principal clinker minerals a'C/sub 2/S and C/sub 3/S; (2) belite sulphoaluminate cement (..beta.. C/sub 2/S, C/sub 4/A/sub 3/S); (3) belite sulphoferrite cement (..beta.. C/sub 2/S, C/sub 4/AF, C/sub 4/A/sub 3/S); (4) NTS cement (alinite).

  16. Tendencias gastronómicas predominantes en la producción de revistas científicas de Iberoamérica

    OpenAIRE

    César Hernández Heredia; Ana Leticia Tamayo Salcedo; Diana Castro Ricalde; Irma Muñoz Muñoz

    2016-01-01

    Se abordan las tendencias gastronómicas con el propósito de conocer las áreas de oportunidad para la investigación en este campo. Se discute acerca de lo que se llama indistintamente ciencia, arte o disciplina y se explican conceptos relacionados con tendencias y modas para diferenciar dichas prácticas en el ámbito gastronómico. Se mencionan tres de las tendencias gastronómicas encontradas mediante una revisión de 142 artículos publicados en revistas indizadas en Redalyc, Latin...

  17. Tendencias en la calidad de vida en países con dependencia mineral

    Directory of Open Access Journals (Sweden)

    Luis J. González Oquendo

    2009-01-01

    Full Text Available El presente trabajo tiene como objetivo describir tendencias a partir de algunos indicadores de calidad de vida en el conjunto de países de dependencia mineral. A partir de gráficos Box-Plot e índices de correlación, se procedió a la descripción de tendencias estadísticas para realizar precisiones en torno a la calidad de vida -analizada a través del índice de desarrollo humano [ÍDH] y componentes- y variables económicas [exportaciones minerales como porcentaje del total de exportaciones y del producto interno bruto] y demográficas [fecundidad, mortalidad infantil]. Aunque no se precisó alguna correlación estadística entre el porcentaje de exportaciones minerales como parte del PIB con el ÍDH o alguno de sus componentes, se encontró relación significativa con el porcentaje como parte del total de exportaciones aunque -en su relación con el IDH y con el índice de logro educativo- sólo había relaciones inversas de carácter leve. En relación con las variables demográficas, sólo se encontró relaciones leves entre el porcentaje de exportaciones minerales sobre exportaciones totales con la tasa de fecundidad total y la tasa de mortalidad infantil, sin que se haya encontrado alguna significatividad en la tasa de mortalidad de niños menores de 5 años. Se precisó que, aunque la mayor parte de los países con dependencia mineral poseen valores ÍDH medio, los valores reflejan fuertes diferencias regionales, distribuciones asimétricas positivas matizadas en lo referente a las exportaciones minerales y dispersión desigual de los valores ÍDH, siendo mayor entre los países de alta dependencia mineral.

  18. Holocene cemented beach deposits in Belize

    Science.gov (United States)

    Gischler, Eberhard; Lomando, Anthony J.

    1997-06-01

    Two types of cemented beach deposits occur on reef islands off the coast of Belize. These are (1) intertidal beachrock that is dominantly cemented by marine aragonite and high-magnesium-calcite cements, and (2) supratidal cayrock that is cemented mainly by vadose low-magnesium-calcite cements. Besides differences in position relative to present sea level and resulting early diagenesic features, beachrock and cayrock can be distinguished on the basis of differences in composition, texture, geographical position, and age. Whereas the composition of beachrock is similar to that of the adjacent marginal reef sediments, cayrock is enriched in benthic foraminifera. Intertidal beachrock is moderately to well sorted and well cemented, while supratidal cayrock is very well sorted, poorly cemented and friable. Beachrock occurs preferentially on windward beaches of sand-shingle Gays on the middle and southern barrier reefs and on the isolated platforms Glovers and Lighthouse Reefs. Cayrock only occurs on larger mangrove-sand Gays of the isolated platforms Turneffe Islands, Lighthouse Reef, and the northern barrier reef. 14C-dating of ten whole-rock and mollusk shell samples produced calibrated dates between AD 345 and AD 1435 for beachrock and between BC 1085 and AD 1190 for cayrock. The large-scale distribution of beachrock in Belize supports the contention that physical processes such as water agitation rather than biological processes control beachrock formation and distribution. Only on windward sides of cays that are close to the reef crest, where large amounts of seawater flush the beaches, considerable amounts of cements can be precipitated to produce beachrock. Cayrock forms due to cementation in the vadose zone and is only preserved on larger, stable mangrove-sand cays.

  19. STUDIES OF CHANGES OF SOME BLOOD PARAMETERS AMONG WORKERS OF CEMENT OF EL MA EL ABIOD TEBESSA ALGERIA

    Directory of Open Access Journals (Sweden)

    M. Aouimeur

    2015-08-01

    Full Text Available In Algeria, the industrial development engenders the appearance of the sanitary and environmental problems resulting from the pollution due to these certain industries such as the industry cimentière. With the aim of estimating the sanitary state of the workers of the cement works; a study was made for 30 workers of the cement works. This study is based on the determination of the values of 07 parameters hématologiques (red blood cells, haemoglobin, hématocrite, average spherical volume, The corpuscular concentration averages in haemoglobin, The corpuscular content averages in haemoglobin and the number of white blood cells and two parameters considered as markers premature of the inflammation (sedimentation speed and protein-C-reactive. These results are compared with two other populations, one of the inhabitants of the region and other one of the inhabitants far from the cement works avec 60 km. The statistical analyses are based on the comparison of the variances and the analysis in main constituent (ACP. The comparison of the variance of the various variable of the individuals show a resemblance between the workers and the inhabitants close to the cement works but significant differences appeared between both populations and those of the cement works for some parameters. The global analysis of these results with the ACP showed a general coherence. The observation of the groups allowed removing some peculiarities.This distribution shows the relation between the functional state and the variation of the parameters.

  20. Effect of cementing technique and cement type on thermal necrosis in hip resurfacing arthroplasty - a numerical study

    NARCIS (Netherlands)

    Janssen, D.; Srinivasan, P.; Scheerlinck, T.; Verdonschot, N.J.J.

    2012-01-01

    Femoral fractures within resurfacing implants have been associated with bone necrosis, possibly resulting from heat generated by cement polymerization. The amount of heat generated depends on cement mantle volume and type of cement. Using finite element analysis, the effect of cement type and volume

  1. The behavior of the micro-mechanical cement-bone interface affects the cement failure in total hip replacement

    NARCIS (Netherlands)

    Waanders, D.; Janssen, D.; Mann, K.A.; Verdonschot, N.J.J.

    2011-01-01

    In the current study, the effects of different ways to implement the complex micro-mechanical behavior of the cement-bone interface on the fatigue failure of the cement mantle were investigated. In an FEA-model of a cemented hip reconstruction the cement-bone interface was modeled and numerically im

  2. Comparison of Temperature Field Distribution between Cement Preclinkering Technology and Cement Precalcining Technology

    Institute of Scientific and Technical Information of China (English)

    XU Xun; WANG Lan

    2016-01-01

    Through the comparison of calcination conditions between cement preclinkering technology and cement precalcining technology, we studied the characteristics of temperature ifeld distribution of cement preclinkering technology systems including cyclone preheater, preclinkering furnace, and rotary kiln. We used numerical simulation method to obtain data of temperature ifeld distribution.Some results are found by system study. The ratio of tail coal of cement preclinkering technology is about 70%, and raw meal temperature can reach 1070℃. ShorterL/D kiln type of preclinkering technology can obtain more stable calcining zone temperature. The highest solid temperature of cement preclinkering technology is higher than 80℃, and high temperature region (>1450℃) length is 2 times, which is beneifcial for calcining clinker and higher clinker quality. So cement preclinkering technology can obtain more performance temperature ifled, which improves both the solid-phase reaction and liquid-phase reaction.

  3. Globalización neoliberal en Costa Rica: panorama de las tendencias en políticas culturales (1990-2010

    Directory of Open Access Journals (Sweden)

    Andrés Mora Ramírez

    2013-08-01

    Full Text Available En los últimos dos decenios, la sociedad costarricense ha pasado por considerables transformaciones enmarcadas en el contexto de la globalización, y bajo el signo del neoliberalismo, visibles en la organización del Estado, la definición del modelo de desarrollo y en el papel de la empresa privada en la definición y promoción de políticas culturales. Las principales tendencias indican que son las fuerzas del mercado y las industrias mediáticas e infocomunicacionales las fuentes del cambio cultural y de una nueva noción de identidad nacional. Over the last two decades, Costa Rican society underwent profound changes in the context of globalization, and under the influence of neoliberalism. Such changes can be identified in the organization of the State, the definition of the development model, and particularly, in the role that private enterprise assumes in defining and promoting cultural policies. The main trends indicate that there are market forces, and media and infocommunication industries that are sources of cultural change and the construction of a new national identity.

  4. INFLUENCE OF GLASS CULLET IN CEMENT PASTES

    Institute of Scientific and Technical Information of China (English)

    A.Karamberi; E.Chaniotakis; D.Papageorgiou; A.Moutsatsou

    2006-01-01

    The present study investigates glass and cement compatibility with a view to use glass as a cement replacement. Amber, flint and green glasses were chosen due to their prevalence in the Greek market as packaging materials. The factors under investigation were the pozzolanicity of the glass cullet, the hydration rate and the mechanical strength development of the cement pastes, as well as the expansion of the specimens due to alkali-silica reaction.Moreover, the potential enhancement of glass pozzolanic activity was examined. The results of the study were encouraging to show the potentiality of utilising glass cullet in cementitious products.

  5. Synthesis of pure Portland cement phases

    DEFF Research Database (Denmark)

    Wesselsky, Andreas; Jensen, Ole Mejlhede

    2009-01-01

    Pure phases commonly found in Portland cement clinkers are often used to test cement hydration behaviour in simplified experimental conditions. The synthesis of these phases is covered in this paper, starting with a description of phase relations and possible polymorphs of the four main phases...... in Portland cement, i.e. tricalcium silicate, dicalcium silicate, tricalcium aluminate and tetracalcium alumino ferrite. Details of the The process of solid state synthesis are is described in general including practical advice on equipment and techniques. Finally In addition, some exemplary mix compositions...

  6. Health promoting behaviors in industrial workers

    Directory of Open Access Journals (Sweden)

    Gulay Yilmazel

    2015-04-01

    CONCLUSIONS: Health promoting behaviors were found to be in moderate level among cement factory workers. In our country, health protection and development programs at the national level would be useful to standardize for employees in the industrial sector. [TAF Prev Med Bull 2015; 14(2.000: 153-162

  7. Cement Manufacturing Plant Guidelines: An Approach to Reconciling the Financing of Cement with Climate Change Objectives

    OpenAIRE

    2010-01-01

    Cement manufacturing is an energy-intensive process, requiring high fuel consumption to operate cement kilns, which in turn generates carbon dioxide (CO2). These Guidelines aim to provide clear and quantitative Minimum Climate Change Performance Criteria necessary for IDB to support projects, as well as guidance on assessing and reducing the greenhouse gas (GHG) emissions of projects. The purpose of the Cement Manufacturing Plant guidelines is to set forth an approach for the financing of new...

  8. Tendencias organizativas y tipos de poder en doce líderes del municipio de San Gil, Santander

    Directory of Open Access Journals (Sweden)

    Wilmer Hernández-Velandia

    2016-09-01

    Full Text Available El presente artículo da a conocer los resultados de la investigación basada en la recuperación etnográfica de los discursos de doce líderes sociales, culturales y de partidos políticos en el municipio de San Gil, Santander, en el marco de las Elecciones Legislativas de 2010 en Colombia. Se logran distinguir dos propuestas así: se identifican dos tendencias organizativas, una partidista y otra de autonomía social, cada una con interpretaciones distintas sobre problemas, propuestas de solución, roles y conceptos base; de otro lado, se deducen dos tipos de poder, uno representativo y otro diversificante, explicando la manera como éstos se fortalecen o debilitan en una u otra tendencia organizativa.

  9. Definición de las tendencias de fertilidad en suelos cafeteros de Charalá, Coromoro y Ocamonte (Santander

    Directory of Open Access Journals (Sweden)

    Héctor Giovanny Galindo-Barrera

    2013-07-01

    Full Text Available Objetivo: Definir las tendencias de fertilidad en suelos cafeteros de Charalá, Coromoro y Ocamonte (Santander. Materiales y métodos. Se utilizó un importante número de análisis de suelos que permitieron recopilar 1485 muestras tomadas desde el año 1991, y que sirvieron como banco de datos para generar tendencias de fertilidad en los suelos cultivados con café de los municipios de Charalá, Coromoro y Ocamonte. Posteriormente, los datos fueron agrupados y organizados a nivel seccional, municipal y veredal, brindando así una mayor escala de detalle, lo que permitió elaborar mapas de fertilidad para la zona, teniendo en cuenta los requerimientos nutricionales para el cultivo de café en Colombia. Resultados. Se observaron condiciones de acidez, bajos contenidos de magnesio, calcio, potasio y condiciones medias de fósforo.

  10. Radiographic appearance of commonly used cements in implant dentistry.

    Science.gov (United States)

    Pette, Gregory A; Ganeles, Jeffrey; Norkin, Frederic J

    2013-01-01

    Cement-retained restorations allow for a conventional fixed partial denture approach to restoring dental implants. However, inadequate removal of excess cement at the time of cementation may introduce a severe complication: cement-induced peri-implantitis. Radiopaque cements are more easily detected on radiographs and should improve the recognition of extravasated cement at the time of insertion. The purpose of this study was to evaluate the radiopacity of commercially available cements in vitro. Eighteen different cements commonly used for luting restorations to implants were tested at both 0.5- and 1.0-mm thicknesses. The cements examined were zinc oxide eugenol, zinc oxide, zinc polycarboxylate, zinc phosphate, resin-reinforced glass ionomer, urethane resin, resin, and composite resin. Two samples of each cement thickness underwent standardized radiography next to an aluminum step wedge as a reference. The mean grayscale value of each of the nine 1-mm steps in the step wedge were used as reference values and compared to each of the cement samples. Temp Bond Clear (resin), IMProv (urethane resin), Premier Implant Cement (resin), and Temrex NE (resin) were not radiographically detectable at either sample thickness. Cements containing zinc were the most detectable upon radiographic analysis. There are significant differences in the radiopacity of many commonly used cements. Since cementinduced peri-implantitis can lead to late implant failure, cements that can be visualized radiographically may reduce the incidence of this problem.

  11. UNA MIRADA A LAS TENDENCIAS Y LOS RETOS DEL VOLUNTARIADO PROCEDER

    Directory of Open Access Journals (Sweden)

    Andrea Rivera Duque

    2016-12-01

    Full Text Available Hoy día, las personas buscan aprovechar su tiempo libre en actividades solidarias. Una de las opcionespor las que más a menudo se inclinan son los voluntariados, tal como se señala en el Informe sobre el estado del voluntariado en el mundo para 2011, de las Naciones Unidas. La poca información concreta y disponible, así como la escasez de referentes acerca del voluntariado tanto a escala nacional como desde el ámbito universitario, es el aspecto más notorio a la hora de hacer un análisis de la realidad de este tipo de movimientos. Pese a ello, algunas fuentes rigurosas y actualizadas nos permiten aproximarnos a esta realidad e identificar algunos de los retos y las tendencias que deben plantearse en dicho ámbito para su futuro. El objetivo de la presente revisión bibliográfica es conocer el estado actual de la realidad de los voluntariados universitarios tomando en cuenta los ámbitos de carácter internacional y nacional, para, con ello, orientar mejor la experiencia extracurricular que se ha hecho con el voluntariado Proceder , del Programa Ciencias del Deporte y la Recreación de la Universidad Tecnológica de Pereira.

  12. La cotidianidad desde la sociolingüística Tendencia de algunos estudios de posgrado

    Directory of Open Access Journals (Sweden)

    Gloria Vargas

    2007-10-01

    Full Text Available Este artículo muestra el Estado del Arte de la Sociolingüística en los programas de Maestría del Seminario Andrés Bello del Instituto Caro y Cuervo, la Universidad Nacional de Colombia, la Universidad de Antioquia y la Universidad del Valle. En el trabajo se tuvieron en cuenta cuatro categorías: el análisis desde los objetivos y la metodología propuestos, mostró una tendencia a los estudios descriptivos correlacionales. Con respecto al nivel de análisis sociolingüístico, la etnografía del habla predominó sobre la microsociolingüística y la macrosociolingüística. La mayoría de las monografías optaron por el análisis de las situaciones y eventos comunicativos. Así mismo, se destacó el tratamiento de la variable social, dentro de las variedades de uso de la lengua.

  13. Nuevas tendencias en la historiografía española

    Directory of Open Access Journals (Sweden)

    SanMartin, Israel

    2007-12-01

    Full Text Available The article is framed in which some historians have denominated “immediate historiography” (it consists of reflecting on the history of the historiography developed on the time of the historian. The investigation in the describes, analyzes and explains the evolution of the recent Spanish historiography. Thus, the author will studie the characteristics of the recent Spanish historiography, the last historiography Spanish tendencies, and will deepen one of them; History to Debate, that will serve as waiting room for the conclusions.

    El artículo se enmarca en lo que algunos historiadores han denominado “historiografía inmediata”, que consiste en reflexionar sobre la historia de la historiografía que se está desarrollando a la par del propio historiador. La investigación describe, analiza y explica la evolución de la historiografía española reciente en los últimos a��os. Así, el autor tratará en su primer apartado las características de la historiografía española reciente, después identificará las últimas tendencias historiográficas españolas, para terminar con la profundización en una de ellas; Historia a Debate, que servirá de antesala para las conclusiones.

  14. TENDENCIAS DEL NEGOCIO DE LAS TELEVISORAS Y PRODUCTORAS COMERCIALES EN EL ESTADO ZULIA

    Directory of Open Access Journals (Sweden)

    Rocío Belandria Cerdeira

    2005-07-01

    Full Text Available Este artículo presenta los resultados de un estudio de campo cuyo objetivo fue identificar las tendencias del negocio en las televisoras y productoras comerciales de la región zuliana. El estudio es de carácter exploratorio, realizado a partir de un trabajo de campo. Se aplicó una entrevista de preguntas abiertas a una muestra no probabilistica intencionada de cuatro televisoras y tres productoras de televisión comerciales de la región. La metodología es cualitativa por lo que el interés está dirigido a la descripción verbal que los informantes proporcionan de los hechos más que su medición. Los resultados arrojados indican que: 1 el negocio de las televisoras se afianza mayormente en la venta de espacios; 2 para las productoras el negocio en crear, producir y atender las necesidades del cliente, 3 el negocio está apalancado en el mercadeo y utiliza variadas estrategias direccionadas en forma descendente desde la gerencia, 4 se arrojan ganancias; y 5 el sector aparece en pleno crecimiento a pesar de la crisis del país.

  15. Tendencias o rupturas de la familia colombiana: una mirada restrospectiva y prospectiva

    Directory of Open Access Journals (Sweden)

    Ligia Echeverri Ángel

    2010-05-01

    Full Text Available Parecería a primera vista que la discusión sobre la prospectiva familiar no fuera de la competencia de los científicos sociales. Sin embargo, la prospectiva descrita como un proceso complejo que guía las decisiones políticas, exige la participación de los científicos sociales para responder a las preguntas: ¿quién define el rumbo de la sociedad?; ¿qué se define como posible y qué como deseable?; ¿por qué se mira al futuro?; Y ¿cómo se logra un proyecto de cambio institucional que apunte al fortalecimiento de la familia? Prospectiva y realidad son dos conceptos continuos pero no contradictorios. Se prospecta para señalar escenarios futuros deseables y posibles, con fundamento en una realidad que tiene una dinámica propia. Esto significa que además de un conocimiento preciso del transfondo histórico y características actuales de una institución la familia para nuestro caso, se requiere una visión de las tendencias hacia el futuro y de las transformaciones contextuales que pueden afectarlas.

  16. Análisis de tendencias de heliofanía efectiva en Argentina

    Directory of Open Access Journals (Sweden)

    Hugo Grossi Gallegos

    2007-12-01

    Full Text Available Se presentan resultados del análisis estadístico de series temporales de promedios anuales de heliofanía efectiva (horas de brillo solar registrados en estaciones de Argentina, que compensan la insuficiencia de datos de irradiación solar y permiten estudiar tendencias relacionadas con el Cambio Climático Global. Se aplicó un estudio previo de consistencia teniendo en cuenta el error de medición, con la aplicación del test de Mann-Kendall y se discuten los resultados obtenidos. Aparecen algunas estaciones en las que los promedios anuales de la heliofanía efectiva decrecen significativamente, agrupándose fundamentalmente en una zona ubicada al noreste de la Pampa Húmeda y al sur de la Mesopotamia.Results of the statistic analysis of time series of annual averages of hours of solar brightness registered in stations of Argentina are presented; these values compensate the insufficiency of data of solar irradiation and allow studying tendencies related to the Global Climatic Change. The measurement error was taken into account in a previous study of consistency, temporal analysis is made with the application of the test of Mann-Kendall and the obtained results are discussed. They appear some stations in which the annual averages of hours of solar brightness decrease significantly, grouping itself essentially in a zone located to the northeast of Humid Pampas and to the south of the Mesopotamia.

  17. Tendencias en los sistemas de indización automática. Estudio evolutivo

    Directory of Open Access Journals (Sweden)

    Gil Leiva, Isidoro

    1996-09-01

    Full Text Available In this article, we present the evolution of automatic indexing and computer-assisted indexing, from the original works, about 1960 up to the present. The systems described have been divided in four sections: systems that use non linguistic methods, systems that use linguistic means, commercialized systems and last trends based upon multimedia. A wide bibliographic review of forty years of automatic indexing systems has been done. Finally, the conclusions are shown.

    Se presenta la evolución de la indización automática y asistida por ordenador desde que se inician las primeras investigaciones, a finales de los años cincuenta, hasta la actualidad. Los sistemas descritos se han dividido en cuatro apartados: aquéllos que utilizan métodos no lingüísticos, los que emplean criterios lingüísticos, los sistemas comercializados, y las últimas tendencias en indización automática de información multimedia. Para el estudio de esta evolución se realiza una amplia revisión bibliográfica que abarca cuatro décadas de indagaciones que han dado lugar a numerosos proyectos de indización automática o asistida por ordenador, de los cuales se examinan más de veinticinco. Finalmente se muestran las conclusiones.

  18. Laboratory development and field application of novel cement system for cementing high-temperature oil wells

    Energy Technology Data Exchange (ETDEWEB)

    Wan, X.; Zhang, H.; Li, Y.; Yang, Y. [SINOPEC, Beijing (China); Shan, H.; Xiao, Z. [OPT, Beijing (China)

    2010-07-01

    The challenges that oil and gas well engineers face when cementing mid-to-high temperature exploration oil and gas wells were discussed. A newly developed cement system with an effective laminar-flow spacer was presented along with case histories that document the system's effectiveness for cementing high temperature exploration wells. The problems associated with cementing high temperature exploration wells include high bottom hole static temperature; very low pump rates; and very long job times. These challenges contribute to the operational risks during cement slurry placement in the wellbore as well as during cement sheath setting during the life of the well. The new cement formulation presented in this paper addresses these challenges. Eight jobs have been completed in the field with much success. The combination of a new retarder and fluid loss control additive improves the system performance considerably in terms of low fluid loss rate, minimal free water, proper rheology, predictable thickening time, high resistance to salt contaminations and no adverse effect on set cement strength. The drilling muds are effectively displaced by the laminar flow spacer, thus improving the cementing bond. 9 refs., 5 tabs., 6 figs.

  19. Slagment Cement Improve the Cement Resistance Toward Acids Attack During Acidizing Treatment

    Directory of Open Access Journals (Sweden)

    Nik Khairul Irfan Bin Nik Ab. Lah.

    2013-05-01

    Full Text Available Acidizing treatment in past experience shows several zonal isolation problems after the treatment. This study presents the effect of the acid treatment toward class G cement and slagment cement as the improvement method to improve the cement resistance toward the acid. Lab experiments were conducted by immerge the respective cement cubes into 12% HCl/3% HF solution for 40 min before several analysis were conducted. Based on the result, the mass loss and compressive strength loss of the cement cubes decrease as the curing temperature and pressure increase due to more evenly distributed cement chemical composition crystal in high curing condition as shown in Scanning Electron Microscopy (SEM analysis. From X-Ray Diffraction (XRD and X-Ray Fluorescence (XRF analysis, only the first layer of the cement cubes shows chemical component change due to the reaction between the acid. This study found that, replacing class G cement to slagment cement can reduce the mass loss and compressive strength loss up to 72% and 82%, respectively.

  20. RE-USE OF SPENT CATALYST FROM OIL-CRACKING REFINERIES AS SUPPLEMENTARY CEMENTING MATERIAL

    Institute of Scientific and Technical Information of China (English)

    S. K. Antiohos; E. Chouliara; S. Tsimas

    2006-01-01

    Advanced technological achievements and the continuous growth of economy have made the disposal,recycle and reuse of industrial by-products a severe challenge. The cement industry is considered one of the key sectors in this effort in successfully (in terms of not extenuating but improving some of the properties of the final product) absorbing large quantities of solid wastes, either as aggregates or as secondary cementitious materials. This not only contributes to the creation of an energy and CO2-emission depository (as commonly used raw materials are spared), but also simultaneously alleviates the acute environmental burden caused by the irresponsible disposal of such by-products. In this study, the possibility of reusing spent fluid catalytic-cracking catalyst (FCC) as a supplementary cementing material(SCM) was examined. A series of tests were conducted, initially aiming at characterizing the material and thereafter evaluating its pozzolanic activity and its effect on the mechanical properties of blended cements. Major findings in this investigation revealed that the use of FCC as a mineral admixture in cement is feasible, strengthening the belief that siliceous glassy residues should represent a steady supply for the construction sector.

  1. Desarrollo y espacios culturales en Valparaíso: Tendencias en las últimas décadas (2000-2016

    Directory of Open Access Journals (Sweden)

    Felipe Espinosa P.

    2016-07-01

    Full Text Available En este artículo, realizamos una lectura al Valparaíso entre los años 2000-2016, considerando para ello dos periodos significativos en el desarrollo cultural reciente: un primer periodo de transición cultural entre los años 2000-2008 y un periodo que tratamos de caracterizar como de reconversión de la economía cultural entre los años 2009-2016. El primer periodo es analizado a partir de los datos publicados en un trabajo el año 2010, mientras que para el segundo periodo, se busca actualizar la discusión a partir de diversos estudios que surgieron en la región acerca del desarrollo de las industrias culturales y la política cultural regional 2011-2016. El análisis al caso de estudio del Centro Cultural Excárcel -actualmente Parque Cultural de Valparaíso-, que acompañó todo este proceso, permiten reconocer algunas de las disputas al interior de este sector. Los resultados indican dos tendencias para los próximos años: la primera enfocada en una política cultural para las industrias creativas, entendidas como creatividad, innovación y tecnología, mientras que la segunda rescata el locus creativo de la ciudad, que ha tendido a expandirse y resignificarse en un circuito más amplio en la región de Valparaíso. Las conclusiones indican un desajuste en los diagnósticos al sector cultural, una bifurcación que complejizará el desarrollo de este sector. Abstract In this article, we perform a reading at Valparaiso between the years 2000-2016, considering for this two significant periods in the recent cultural development: a first period of cultural transition between the years 2000-2008 and a period that we try to characterize as conversion of the cultural economy in the years 2009-2016. The first period is analyzed from the data published in a paper in 2010, while for the second period, we seek to update the discussion from various studies that emerged in the region about the development of cultural industries and the Regional

  2. Causas y tendencia de la mortalidad en una prisión española (1994-2009

    Directory of Open Access Journals (Sweden)

    Julio García-Guerrero

    2011-01-01

    Full Text Available Fundamento, El conocimiento de las causas de mortalidad puede ser una herramienta valiosa para procurar mejores cuidados de salud a las personas encarceladas. El objetivo del trabajo es describir la mortalidad y su tendencia en nuestro centro. Método, Estudio descriptivo de los fallecimientos ocurridos entre el 01/01/1994 y 31/12/2009. Se compararon mediante el test exacto de Fisher dos periodos de 8 años para valorar cambios en las causas de mortalidad. Previa estandarización indirecta de tasas, comparamos la mortalidad de nuestro centro con la del resto de las prisiones españolas. Mediante un modelo de regresión lineal establecimos la tendencia de las tasas de mortalidad. Resultados, Hubo 59 defunciones, 58 en hombres, con una mediana de edad de 34,9 años (28,7- 40,4. El 64,4% eran VIH+. Desde 1994 hasta 2001 la principal causa de mortalidad fue la infección VIH (48,6% y la segunda los eventos cardiovasculares (10,8%, mientras que entre 2002 y 2009 los eventos cardiovasculares causaron un 31,8% y la infección VIH un 22,7% (p=0,026. Las tasas crudas de mortalidad anual tuvieron tendencia descendente a razón de 0,485 muertes internos/año (IC 95%, 0,864 a -0,107. Estandarizando tasas corresponderían 42 muertes esperadas en todo el período, con una Razón de Mortalidad Estandarizada de 1,407 (IC 95%, 1,071 a 1,816. Conclusiones, La principal causa de mortalidad fue la enfermedad no-VIH, fundamentalmente por eventos cardiovasculares. La tendencia de la tasa de mortalidad fue descendente, aunque observamos un 40,7% más de defunciones de las que cabría esperar.

  3. The Setting Chemistry of Glass Ionomer Cement

    Institute of Scientific and Technical Information of China (English)

    CHENG Hanting; LIU Hanxing; ZHANG Guoqing

    2005-01-01

    The setting chemistry of glass ionomer cement was investigated by using mechanical determination of compressive strength at predetermined intervals, and measurement of structure changes of corresponding fracture sample by means of IR spectra and differential scanning calorimetry ( DSC). Zinc polycarboxylate cement was used as a comparison sample. The compressive strength of glass ionomer cement (GIC) increases with aging. IR spectra and DSC of corresponding fracture sample show the structure changes of the matrix and interface layer comprising of silica gel during the predetermined intervals studied, however, no significant changes occur in the zinc polycarxyolate cement. Hence the structure changes of the matrix and/or interface layer are responsible for compressive strength increasing with aging. The structure changes include the crosslink density, the ratio of complex form to ionic form, the content ratio of Al-PAA to Ca-PAA, the forming and mauring process of the interface layer comprising of silica gel.

  4. Dicalcium phosphate cements: brushite and monetite.

    Science.gov (United States)

    Tamimi, Faleh; Sheikh, Zeeshan; Barralet, Jake

    2012-02-01

    Dicalcium phosphate cements were developed two decades ago and ever since there has been a substantial growth in research into improving their properties in order to satisfy the requirements needed for several clinical applications. The present paper presents an overview of the rapidly expanding research field of the two main dicalcium phosphate bioceramics: brushite and monetite. This review begins with a summary of all the different formulae developed to prepare dicalcium phosphate cements, and their setting reaction, in order to set the scene for the key cement physical and chemical properties, such as compressive and tensile strength, cohesion, injectability and shelf-life. We address the issue of brushite conversion into either monetite or apatite. Moreover, we discuss the in vivo behavior of the cements, including their ability to promote bone formation, biodegradation and potential clinical applications in drug delivery, orthopedics, craniofacial surgery, cancer therapy and biosensors.

  5. Tendencia poblacional en tres colonias de gaviota patiamarilla Larus michahellis Naumann, 1840 en Gipuzkoa: 2000-2013

    Directory of Open Access Journals (Sweden)

    Arizaga, J., Aldalur, A., Herrero, A.

    2014-01-01

    Full Text Available En este trabajo se analiza la evolución de la población de gaviota patiamarilla Larus michahellis Naumann, 1840 en Gipuzkoa, con el fin de determinar si esta población ha aumentado o no durante los últimos años. Se desarrolla un modelo de crecimiento poblacional a partir de datos de censos llevados a cabo en tres colonias de referencia (Ulia-Faro, Santa Clara y Geteria, para el periodo 2000-2013, mediante el programa TRIM. La población estudiada ha pasado de 354 parejas (pp. en 2000 a 299 pp. en 2013. Observamos un ajuste malo de nuestros modelos (modelo de crecimiento nulo y modelo que estima un cambio log-lineal de la población a los datos que, no obstante, tanto para todas las colonias como para cada una de las colonias por separado, el modelo que estima un cambio log-lineal se ajusta mejor a los datos. Globalmente, la tendencia de las colonias es incierta (estable. Por colonias, las tendencias son dispares, lo cual indicaría dinámicas distintas. En el caso de Ulia la colonia disminuye durante el periodo de estudio, mientras que en Santa Clara la colonia es estable, y en Getaria aumenta. Globalmente, durante el periodo de estudio, el descenso de Ulia se habría compensado con las tendencias observadas en las otras dos colonias.

  6. Dynamic properties of composite cemented clay

    Institute of Scientific and Technical Information of China (English)

    蔡袁强; 梁旭

    2004-01-01

    In this work,the dynamic properties of composite cemented clay under a wide range of strains were studied considering the effect of different mixing ratio and the change of confining pressures through dynamic triaxial test. A simple and practical method to estimate the dynamic elastic modulus and damping ratio is proposed in this paper and a related empirical normalized formula is also presented. The results provide useful guidelines for preliminary estimation of cement requirements to improve the dynamic properties of clays.

  7. Physical Properties of Acidic Calcium Phosphate Cements

    OpenAIRE

    2014-01-01

    The gold standard for bone replacement today, autologous bone, suffers from several disadvantages, such as the increased risk of infection due to the need for two surgeries. Degradable synthetic materials with properties similar to bone, such as calcium phosphate cements, are a promising alternative. Calcium phosphate cements are suited for a limited amount of applications and improving their physical properties could extend their use into areas previously not considered possible. For example...

  8. Cement stratigraphy: Image probes of cathodoluminescent facies.

    OpenAIRE

    Vuillemin, Aurèle; Ndiaye, Mapathe; Martini, Rossana; Davaud, Eric Jean

    2011-01-01

    Cement stratigraphy of carbonates aims to establish the chronology of processes involved in the rock diagenesis. Regional cement stratigraphy allows correlations and understanding of the petrological heterogeneities in reservoirs and aquifers, but is a long and rigorous approach. This article exposes a methodology of image analysis that facilitates the spatial correlation of diagenetic events in carbonate rocks. Based on the statistical comparison of signals extracted from the red spectrum em...

  9. Low-cycle fatigue of surgical cements

    Directory of Open Access Journals (Sweden)

    A. Balin

    2007-01-01

    Full Text Available Purpose: In case when surgical cement is used to fix endoprostheses of joints the fatigue character of mechanicalinterraction in the cement seems to be a significant importance. The paper suggests to adapt the research methodof low cycle fatigue for modelling the loads on surgical cements in an artificial hip joint. Surgical cements havealso been modified in order to improve their functional properties.Design/methodology/approach: Low cycle fatigue tests were conducted on samples made from Palamedcement without an addition and on samples modified with glassy carbon and titanium. The tests were conductedon a servohydraulic fatigue testing machine, MTS-810, with displacement control.Findings: Fatigue tests proved viscoelastic character of all the tested materials. During the fatigue tests, thephenomenon of stress cyclic relaxation was observed.Research limitations/implications: Modelling the loadings of cement in endoprostheses of joints with the lowcycle fatigue method takes into account all high value stresses, while cement is being used for endoprosthesesfor many years in the conditions of random stress and deformation courses. Therefore the obtained stress anddeformation values are bigger than those which would have been obtained in real conditions in the same time.Practical implications: The low cycle fatigue tests carried out showed how important is the factor of timefor the behavior of surgical cement in the conditions of changeable loadings. This fact is essential to assessits usability for endoprosthesoplasty of joints, specially of a hip joint. Post deformation return which is acharacteristic feature for material viscoelasticity enables its regeneration conditioning expected durability ofendoprosthesis of joints.Originality/value: Low cycle fatigue testing method for modelling of loads on surgical cement in artificial hipjoint enables to carry out the tests in a shorter period of time.

  10. Continued stabilization of Triathlon cemented TKA

    OpenAIRE

    Molt, Mats; Ryd, Leif; Toksvig-Larsen, Sören

    2016-01-01

    Background and purpose There is a general call for phased introduction of new implants, and one step in the introduction is an early evaluation of micromotion. We compared the micromotion in the Triathlon and its predecessor, the Duracon total knee prosthesis, concentrating especially on continuous migration over 5 years of follow-up. Patients and methods 60 patients were randomized to receive either a cemented Triathlon total knee prosthesis or a cemented Duracon total knee prosthesis. 3-D t...

  11. Treatment and recycling of asbestos-cement containing waste

    Energy Technology Data Exchange (ETDEWEB)

    Colangelo, F. [Department of Technology, University Parthenope, Naples (Italy); Cioffi, R., E-mail: raffaele.cioffi@uniparthenope.it [Department of Technology, University Parthenope, Naples (Italy); Lavorgna, M.; Verdolotti, L. [Institute for Biomedical and Composite Materials - CNR, Naples (Italy); De Stefano, L. [Institute for Microelectronics and Microsystems - CNR, Naples (Italy)

    2011-11-15

    Highlights: {yields} Asbestos-cement wastes are hazardous. {yields} High energy milling treatment at room temperature allows mineralogical and morphological transformation of asbestos phases. {yields} The obtained milled powders are not-hazardous. {yields} The inert powders can be recycled as pozzolanic materials. {yields} The hydraulic mortars containing the milled inert powders are good building materials. - Abstract: The remediation of industrial buildings covered with asbestos-cement roofs is one of the most important issues in asbestos risk management. The relevant Italian Directives call for the above waste to be treated prior to disposal on landfill. Processes able to eliminate the hazard of these wastes are very attractive because the treated products can be recycled as mineral components in building materials. In this work, asbestos-cement waste is milled by means of a high energy ring mill for up to 4 h. The very fine powders obtained at all milling times are characterized to check the mineralogical and morphological transformation of the asbestos phases. Specifically, after 120 min of milling, the disappearance of the chrysotile OH stretching modes at 3690 cm{sup -1}, of the main crystalline chrysotile peaks and of the fibrous phase are detected by means of infrared spectroscopy and X-ray diffraction and scanning electron microscopy analyses, respectively. The hydraulic behavior of the milled powders in presence of lime is also tested at different times. The results of thermal analyses show that the endothermic effects associated to the neo-formed binding phases significantly increase with curing time. Furthermore, the technological efficacy of the recycling process is evaluated by preparing and testing hydraulic lime and milled powder-based mortars. The complete test set gives good results in terms of the hydration kinetics and mechanical properties of the building materials studied. In fact, values of reacted lime around 40% and values of compressive

  12. Influence of Cellulose Ethers on Hydration Products of Portland Cement

    Institute of Scientific and Technical Information of China (English)

    MA Baoguo; OU Zhihua; JIAN Shouwei; XU Rulin

    2011-01-01

    Cellulose ethers are widely used to mortar formulations, and it is significant to understand the interaction between cellulose ethers and cement pastes. FT-IR spectra, thermal analysis and SEM are used to investigate hydration products in the cement pastes modified by HEMC and HPMC in this article. The results show that the hydration products in modified cement pastes were finally identical with those in the unmodified cement paste, but the major hydration products, such as CH (calcium hydroxide), ettringite and C-S-H, appeared later in the modified cement pastes than in the unmodified cement paste. The cellulose ethers decrease the outer products and increase inner products of C-S-H gels. Compared to unmodified cement pastes, no new products are found in the modified cement pastes in the present experiment. The HEMC and HPMC investigation shows almost the same influence on the hydration products of Portland cement.

  13. Investigation of Possible Wellbore Cement Failures During Hydraulic Fracturing Operations

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jihoon; Moridis, George

    2014-11-01

    We model and assess the possibility of shear failure, using the Mohr-Coulomb model ? along the vertical well by employing a rigorous coupled flow-geomechanic analysis. To this end, we vary the values of cohesion between the well casing and the surrounding cement to representing different quality levels of the cementing operation (low cohesion corresponds to low-quality cement and/or incomplete cementing). The simulation results show that there is very little fracturing when the cement is of high quality.. Conversely, incomplete cementing and/or weak cement can causes significant shear failure and the evolution of long fractures/cracks along the vertical well. Specifically, low cohesion between the well and cemented areas can cause significant shear failure along the well, but the same cohesion as the cemented zone does not cause shear failure. When the hydraulic fracturing pressure is high, low cohesion of the cement can causes fast propagation of shear failure and of the resulting fracture/crack, but a high-quality cement with no weak zones exhibits limited shear failure that is concentrated near the bottom of the vertical part of the well. Thus, high-quality cement and complete cementing along the vertical well appears to be the strongest protection against shear failure of the wellbore cement and, consequently, against contamination hazards to drinking water aquifers during hydraulic fracturing operations.

  14. Reversing the trend toward failure/Revirtiendo la tendencia al fracaso

    Directory of Open Access Journals (Sweden)

    Edward J. Schauer (Estados Unidos de América

    2014-08-01

    Full Text Available In order to solve a problem or reverse a trend, the researcher must first identify the problem, and then suggest solutions or resolutions for that problem so as to offer hope for the future. From all indications, African American students are lagging behind in college education. Of those who do come to college, a troubling percentage do not persevere to graduation. Among those most at risk for failure to succeed in college are African American males. On the average, Black males in America appear to be in deep trouble: For example, many more college aged Black men are in prison than are enrolled in higher education. A Justice Policy study in 2000 (Associated Press, March 28, 2006 reported that fewer African American men were in higher education (603,000 than were in prison and jail (791,600; and the rate continues to diverge (Schauer & Schauer, 2006 & 2007a. This debilitating trend must be reversed and one available alternative is to support those who choose education. Therefore, it would seem to make sense that once these young people are in college, every effort should be made to keep them there. By studying some of the correlates of Black male success, it is hoped that more African American men can be aided toward attaining college degrees and greater career mobility through interventions more accurately focused upon meeting their precise needs (Schauer & Schauer, 2007a. Con el fin de resolver un problema o revertir una tendencia, el investigador debe primero identificar el problema y luego sugerir soluciones o resoluciones para ese problema con el fin de ofrecer esperanzas para el futuro. De todas las indicaciones, los estudiantes afroamericanos están quedando rezagados en la educación universitaria. De los que llegan a la Universidad, un porcentaje preocupante no perseverar a la graduación. Entre quienes más en riesgo por la falta de éxito en la Universidad están los hombres afroamericanos. En promedio, los varones negros en Estados

  15. Attenuation properties of cement composites: Experimental measurements and Monte Carlo calculations

    Science.gov (United States)

    Florez Meza, Raul Fernando

    Developing new cement based materials with excellent mechanical and attenuation properties is critically important for both medical and nuclear power industries. Concrete continues to be the primary choice material for the shielding of gamma and neutron radiation in facilities such as nuclear reactors, nuclear waste repositories, spent nuclear fuel pools, heavy particle radiotherapy rooms, particles accelerators, among others. The purpose of this research was to manufacture cement pastes modified with magnetite and samarium oxide and evaluate the feasibility of utilizing them for shielding of gamma and neutron radiation. Two different experiments were conducted to accomplish these goals. In the first one, Portland cement pastes modified with different loading of fine magnetite were fabricated and investigated for application in gamma radiation shielding. The experimental results were verified theoretically through XCOM and the Monte Carlo N-Particle (MCNP) transport code. Scanning electron microscopy and x-ray diffraction tests were used to investigate the microstructure of the samples. Mechanical characterization was also perfornmed by compression testing. The results suggest that fine magnetite is a suitable aggregate for increasing the compressive and flexural strength of white Portland cement pastes; however, there is no improvement of the attenuation at intermediate energy (662 keV). For the second experiment, cement pastes with different concentrations of samarium oxide were fabricated and tested for shielding against thermal neutrons. MCNP simulations were used to validate the experimental work. The result shows that samarium oxide increases the effective thermal cross section of Portland cement and has the potential to replace boron bearing compounds currently used in neutron shielding.

  16. CEMEX: Cement Manufacturer Saves 2.1 Million kWh Annually with a Motor Retrofit Project

    Energy Technology Data Exchange (ETDEWEB)

    2005-11-01

    This DOE Industrial Technologies Program spotlight describes how the CEMEX cement manufacturing plant in Davenport, California, saves 2 million kWh and $168,000 in energy costs annually by replacing 13 worn-out motors with new energy-efficient ones.

  17. CEMEX: Cement Manufacturer Saves 2.1 Million kWh Annually with a Motor Retrofit Project

    Energy Technology Data Exchange (ETDEWEB)

    None

    2010-06-25

    This DOE Industrial Technologies Program spotlight describes how the CEMEX cement manufacturing plant in Davenport, California, saves 2 million kWh and $168,000 in energy costs annually by replacing 13 worn-out motors with new energy-efficient ones.

  18. Energy Efficiency Improvement and Cost Saving Opportunities for Cement Making An ENERGY STAR® Guide for Energy and Plant Managers

    NARCIS (Netherlands)

    Worrell, E.; Kermeli, Katerina; Galitsky, Christina

    2013-01-01

    The cost of energy as part of the total production costs in the cement industry is significant, typically at 20 to 40% of operational costs, warranting attention for energy efficiency to improve the bottom line. Historically, energy intensity has declined, although more recently energy intensity see

  19. Characterization of cement minerals, cements and their reaction products at the atomic and nano scale

    DEFF Research Database (Denmark)

    Skibsted, Jørgen; Hall, Christopher

    2008-01-01

    Recent advances and highlights in characterization methods are reviewed for cement minerals, cements and their reaction products. The emphasis is on X-ray and neutron diffraction, and on nuclear magnetic resonance methods, although X-ray absorption and Raman spectroscopies are discussed briefly...

  20. Métodos de control en sistemas domóticos: últimas tendencias en sistemas distribuidos

    Directory of Open Access Journals (Sweden)

    Moreno Navarro, I.

    1999-02-01

    Full Text Available Control systems lie amongst the most difficult issues to be tackled when it comes to designing home automation systems. Two classical tendencies may be considered to solve this problem. The first one consists of a centralised control system, whereas the second option advocates for a distributed network, where piece would take up certain responsibilities in the control of the whole system. In this paper we analyse some of the latest developments as regards programming distributed networks, focusing on home automation, specially Java and the latest Jini environments have dramatically improved the potential of such kind of distributed systems, thanks to them, it is possible to build a heterogeneous network including devices from different brands which work in collaborative systems, thus avoiding complex configurations.

    Uno de los aspectos más delicados a la hora de diseñar un sistema domótico es el que se refiere al modelo de control que deseamos establecer. Podemos considerar dos tendencias clásicas: la que trata de establecer un control centralizado del sistema y la que propone un control mucho más descentralizado, donde cada aparato seria responsable de cierta parte de la gestión del control ejercido sobre toda la red. En este articulo tratamos de profundizar en las últimas novedades aparecidas en el campo de la programación de los controladores asociados a una red domótica, en particular Java y el más reciente Jini, que aportan una serie de soluciones que facilitan la compatibilidad entre dispositivos de distintos fabricantes y apuestan claramente por una arquitectura de tipo distribuido, dotando a las redes domóticas de una flexibilidad y un potencial de crecimiento inusitados.