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1

Copolymer for cement admixtures and its production process and use  

US Patent & Trademark Office Database

The present invention provides: a copolymer for cement admixtures which displays high dispersibility with a small adding amount and excellent dispersibility particularly even in a high water reducing ratio area, a cement admixture utilizing the copolymer, and a cement composition, and further, a production process for the copolymer. The copolymer for cement admixtures comprises: constitutional unit (I) derived from unsaturated polyalkylene glycol ether monomer (a) having an alkenyl group having 5 carbon atoms and an oxyalkylene group having 2 to 18 carbon atoms with an average addition number of moles of the oxyalkylene groups to be in the range of 10 to 300; and constitutional unit (II) derived from unsaturated monocarboxylic acid monomer (b). The cement admixture includes the copolymer for cement admixtures as an essential component, and may further include a defoaming agent. The cement composition includes the copolymer for cement admixtures, and cement as essential components. The production process for the copolymer comprises: copolymerizing comonomers including unsaturated polyalkylene glycol ether monomer (a) and unsaturated monocarboxylic monomer (b) as essential components by use of a chain-transfer agent, and/or adjusting pH of a resultant reaction mixture to not less than 5 after the copolymerization.

2004-04-27

2

STAGE MULTI----SITE AGGREGATE PRODUCTION AND SITE AGGREGATE PRODUCTION AND SITE AGGREGATE PRODUCTION AND SITE AGGREGATE PRODUCTION AND DISTRIBUTION PLANNING MODEL FOR A CONTINUOUS DISTRIBUTION PLANNING MODEL FOR A CONTINUOUS DISTRIBUTION PLANNING MODEL FOR A CONTINUOUS DISTRIBUTION PLANNING MODEL FOR A CONTINUOUS CEMENT MANUFACTURING PROCESS CEMENT MANUFACTURING PROCESS CEMENT MANUFACTURING PROCESS CEMENT MANUFACTURING PROCESS  

Microsoft Academic Search

Abstract: Abstract: Abstract: Production planning is an important activity in process companies, since it deals with production resources (work-force and production capacity) dimensioning and inventory management. This paper presents an Aggregate Production and Distribution Planning (APDP) model for cement industry to help managers to evaluate the need and the relevance of integrate production and distribution decisions. The Mixed Integer Linear

Luiz Otavio; Zavalloni Proto; Marco Aurélio de Mesquita

3

[Environment load from China's cement production].  

PubMed

Based on the life-cycle theory, a quantitative evaluation of the environment load caused by cement manufacturing in China was carried out with the application of the CML. environmental impact assessment method. The results show that global warming potential, energy depletion potential and abiotic depletion potential make the main contribution to the environment impact, their environmental loads corresponding to identical environmental impact sorts being 2.76%, 2.34% and 1.39% of the overall load of the whole world, respectively. In 2004, the environment load from cement manufacturing in China is roughly 1.28% of the overall load of the whole world, in which the environmental loads from the shaft kiln processing, wet rotary processing and new-type dry processing being 0.84%, 0.12% and 0.32%, respectively. And it can be reduced to about 1% by replacing backward production processes with the dry method production process. PMID:17256624

Zhu, Tian-le; He, Wei; Zeng, Xiao-lan; Huang, Xin; Ma, Bao-guo

2006-10-01

4

Process for converting coal ash slag into portland cement  

Microsoft Academic Search

Disclosed is a manufacturing process for converting coal ash slag from a slagging coal gasifier into a marketable cement product having the characteristics and qualities of portland cement. This process comprises the steps of transferring molten slag from a slagging coal gasifier to a melt chamber and reacting it with a mineral containing lime, for example: calcium oxide, calcium hydroxide

Fondriest

1979-01-01

5

Hydrogen energy from coupled waste gasification and cement production—a thermochemical concept study  

Microsoft Academic Search

A plant concept for hydrogen production from waste gasification coupled with cement manufacturing is presented. Hot precalcined cement meal, from the operating cement process, is used as heat carrier to provide energy required by the parallel arranged gasifier. The amount of CaO present in the cement meal operates simultaneously as an effective in situ CO2-sorbent. First, a practical case study

Steffen Weil; Stefan Hamel; Wolfgang Krumm

2006-01-01

6

Identifying improvement potentials in cement production with life cycle assessment.  

PubMed

Cement production is an environmentally relevant process responsible for 5% of total anthropogenic carbon dioxide emissions and 7% of industrial fuel use. In this study, life cycle assessment is used to evaluate improvement potentials in the cement production process in Europe and the USA. With a current fuel substitution rate of 18% in Europe and 11% in the USA, both regions have a substantial potential to reduce greenhouse gas emissions and save virgin resources by further increasing the coprocessing of waste fuels. Upgrading production technology would be particularly effective in the USA where many kiln systems with very low energy efficiency are still in operation. Using best available technology and a thermal substitution rate of 50% for fuels, greenhouse gas emissions could be reduced by 9% for Europe and 18% for the USA per tonne of cement. Since clinker production is the dominant pollution producing step in cement production, the substitution of clinker with mineral components such as ground granulated blast furnace slag or fly ash is an efficient measure to reduce the environmental impact. Blended cements exhibit substantially lower environmental footprints than Portland cement, even if the substitutes feature lower grindability and require additional drying and large transport distances. The highest savings in CO(2) emissions and resource consumption are achieved with a combination of measures in clinker production and cement blending. PMID:21047057

Boesch, Michael Elias; Hellweg, Stefanie

2010-12-01

7

Optimization and characterization of a cemented ultimate-storage product  

NASA Astrophysics Data System (ADS)

The U- and Pu-containing packaging wastes can be homogeneously cemented after a washing and fragmentation process. Both finely crushed and coarsely fragmented raw wastes yield products with sufficient mechanical stability. The processability limit of the coarsely fragmented raw waste using cement paste or mortar is largely determined by the cellulose content, which is not to exceed 1.3% by weight in the end waste. Of 9 binders studied, the most corrosion-resistant products were obtained with blast-furnace slag cement, whereas poured concrete and Maxit are much less resistant in five-component brine. In the cemented product, hydrolysis of plasticizers (DOP) from plastics (PVC) occurs, leading to release of 2-ethyl-hexanol. This reaction occurs to a much lower degree with blast-furnace slag cement than with all other binders studied. The binder chosen for further tests consists of blast-furnace slag cement, concrete fluidizer and a stabilizer, and is processed at a W/C ratio of 0.43.

Brunner, H.

1981-12-01

8

Dust exposure and respiratory health effects in cement production.  

PubMed

Dust can be produced by almost all production processes in Portland cement factory. Dust exposure potentially can affect respiratory function. But evidence for respiratory effect of cement dust exposure has not been conclusive. In this study we assessed effect of cement dust exposure on respiratory function in a cement production factory. A respiratory symptoms questionnaire was completed and pulmonary function tests were carried out on 94 exposed and 54 non exposed workers at a cement factory in the east of Iran. Additionally, respirable dust level was determined by the gravimetric method. X-ray fluorescence (XRF) technique was performed to determine the silica phases and the SiO(2) contents of the bulk samples. The arithmetic means (AM) of personal respirable dust were 30.18 mg/m(3) in the crushing, 27 mg/m(3) in the packing, 5.4 mg/m(3) in the cement mill, 5.9 mg/m(3) in the kiln and 5.48 mg/m(3) in the maintenance that were higher than threshold limit value (TLV) of the American Conference of Governmental Industrial Hygienists (ACGIH) which is 5 mg/m(3). This value in the unexposed group was 0.93 mg/m(3). In this study cough, sputum, wheezing and dyspnea were more prevalent among exposed subjects. Exposed workers compared to the unexposed group showed significant reduction in Forced Expiratory Volume in one second (FEV(1)), Forced Vital Capacity (FVC), and Forced Expiratory Flow between 25% and 75% of the FVC (FEF(25-75%)) (P<0.05). It can be concluded that in our study there was close and direct association between cement dust exposure and functional impairment among the cement factory workers. PMID:22359082

Kakooei, Hossein; Gholami, Abdollah; Ghasemkhani, Mehdi; Hosseini, Mostapha; Panahi, Davoud; Pouryaghoub, Golamreza

2012-01-01

9

Suspension process for cement synthesis. Final report, November 1986March 1989  

Microsoft Academic Search

The Gas Research Institute has initiated a program to develop an advanced gas-fired cement synthesis process which will markedly reduce product processing time, lower maintenance and initial capital costs, minimize alkali sulfate formation, and mitigate greenhouse gaseous emissions compared to conventional cement pyroprocessing technology. In the advanced process, pellets of agglomerated batch enter at the top of a vertical shaft

Zappa

1989-01-01

10

Microscale Investigation of Arsenic Distribution and Species in Cement Product from Cement Kiln Coprocessing Wastes  

PubMed Central

To improve the understanding of the immobilization mechanism and the leaching risk of Arsenic (As) in the cement product from coprocessing wastes using cement kiln, distribution and species of As in cement product were determined by microscale investigation methods, including electron probe microanalysis (EPMA) and X-ray absorption spectroscopy. In this study, sodium arsenate crystals (Na3AsO412H2O) were mixed with cement production raw materials and calcined to produce cement clinker. Then, clinker was mixed water to prepare cement paste. EPMA results showed that As was generally distributed throughout the cement paste. As content in calcium silicate hydrates gel (C-S-H) was in low level, but higher than that in other cement mineral phases. This means that most of As is expected to form some compounds that disperse on the surfaces of cement mineral phases. Linear combination fitting (LCF) of the X-ray absorption near edge structure spectra revealed that As in the cement paste was predominantly As(V) and mainly existed as Mg3(AsO4)2, Ca3(AsO4)2, and Na2HAsO4.

Yang, Yufei; Xue, Jingchuan; Huang, Qifei

2013-01-01

11

Microscale investigation of arsenic distribution and species in cement product from cement kiln coprocessing wastes.  

PubMed

To improve the understanding of the immobilization mechanism and the leaching risk of Arsenic (As) in the cement product from coprocessing wastes using cement kiln, distribution and species of As in cement product were determined by microscale investigation methods, including electron probe microanalysis (EPMA) and X-ray absorption spectroscopy. In this study, sodium arsenate crystals (Na3AsO412H2O) were mixed with cement production raw materials and calcined to produce cement clinker. Then, clinker was mixed water to prepare cement paste. EPMA results showed that As was generally distributed throughout the cement paste. As content in calcium silicate hydrates gel (C-S-H) was in low level, but higher than that in other cement mineral phases. This means that most of As is expected to form some compounds that disperse on the surfaces of cement mineral phases. Linear combination fitting (LCF) of the X-ray absorption near edge structure spectra revealed that As in the cement paste was predominantly As(V) and mainly existed as Mg3(AsO4)2, Ca3(AsO4)2, and Na2HAsO4. PMID:24223030

Yang, Yufei; Xue, Jingchuan; Huang, Qifei

2013-01-01

12

Utilization of red mud in cement production: a review.  

PubMed

Red mud is a solid waste residue of the digestion of bauxite ores with caustic soda for alumina production. Its disposal remains a worldwide issue in terms of environmental concerns. During the past decades, extensive work has been done by a lot of researchers to develop various economic ways for the utilization of red mud. One of the economic ways is using red mud in cement production, which is also an efficient method for large-scale recycling of red mud. This paper provides a review on the utilization of red mud in cement production, and it clearly points out three directions for the use of red mud in cement production, namely the preparation of cement clinkers, production of composite cements as well as alkali-activated cements. In the present paper, the chemical and mineralogical characteristics of red mud are summarized, and the current progresses on these three directions are reviewed in detail. PMID:21930526

Liu, Xiaoming; Zhang, Na

2011-10-01

13

[Atmospheric emission of PCDD/Fs from modern dry processing cement kilns with preheating in the southwest area, China].  

PubMed

Six cement kilns were measured for emissions of PCDD/Fs in the Southwest Area, China. The results indicated that the emission levels of PCDD/Fs were 0.0029-0.0062 ng-m(-3) (Average, 0.0043 ng X m(-3)) from cement kilns which did not burn solid waste, and 0.028 ng X m(-3) from co-processing sewage sludge in cement kiln. The levels of PCDD/Fs emissions from cement manufacturing in the Southwest Area were significantly below the national emissions standard (0.1 ng x m(-3)). Emission factors of PCDD/Fs from the six cement kilns varied between 0.0089 and 0.084 microg x t(-1) cement, which were near or below the lowest emission factor reported by UNEP in 2005. Moreover, the emission factor of PCDD/Fs from co-processing sewage sludge in cement kiln was 7.6 times of the average factors from the other five cement kilns. Moreover,congener distribution of PCDD/F in stack gas from the two types of cement kilns was very different. The results showed that modern dry process cement kilns with preheating have lower emissions of PCDD/Fs. This suggested that the product of co-processing solid waste in cement kilns should be largely enhanced in China in future. PMID:24720182

Zhang, Xiao-Ling; Lu, Yi; Jian, Chuan; Guo, Zhi-Shun; Zhu, Ming-Ji; Deng, Li; Sun, Jing; Zhang, Qin

2014-01-01

14

Sialite binary wet cement, its production method and usage method  

US Patent & Trademark Office Database

The technical field of the invention belongs to concrete and cement. The invention relates to a sialite binary wet cement and its package, transportation, storage and application. The sialite binary wet cement is composed of a "female body" as a primary component and a "male body" as a secondary component both of which are produced, stored, and transported separately, and are mixed together when they are used, wherein the "female body" and the "male body" each have a specific surface area of 2800-7500 cm.sup.2/g, the "female body" is mainly composed of inorganic cementitious materials and water, and it is in slurry, paste or wet powder form during the whole period of its production, storage, transportation and usage; the "male body" is mainly composed of inorganic cementitious materials, and it can be a wet form or a dry powder form. When they are used, the "female body" and the "male body" are mixed together with a small amount of regulating agents. There is no generation of dust, SO.sub.2, NOx and CO.sub.2 during production and application of the sialite binary wet cement. Therefore heavy pollution of a traditional cement industry is avoided, and energy consumption and cost of product are decreased. The starting materials of the said cement mainly come from natural mineral, various slag and cinder. The said cement can be used for building, traffic, water conservancy, mine filling, timbering, and solidation of roadbed.

2010-05-04

15

Utilization of flotation wastes of copper slag as raw material in cement production.  

PubMed

Copper slag wastes, even if treated via processes such as flotation for metal recovery, still contain heavy metals with hazardous properties posing environmental risks for disposal. This study reports the potential use of flotation waste of a copper slag (FWCS) as iron source in the production of Portland cement clinker. The FWCS appears a suitable raw material as iron source containing >59% Fe(2)O(3) mainly in the form of fayalite (Fe(2)SiO(4)) and magnetite (Fe(3)O(4)). The clinker products obtained using the FWCS from the industrial scale trial operations over a 4-month period were characterised for the conformity of its chemical composition and the physico-mechanical performance of the resultant cement products was evaluated. The data collected for the clinker products produced using an iron ore, which is currently used as the cement raw material were also included for comparison. The results have shown that the chemical compositions of all the clinker products including those of FWCS are typical of a Portland cement clinker. The mechanical performance of the standard mortars prepared from the FWCS clinkers were found to be similar to those from the iron ore clinkers with the desired specifications for the industrial cements e.g. CEM I type cements. Furthermore, the leachability tests (TCLP and SPLP) have revealed that the mortar samples obtained from the FWCS clinkers present no environmental problems while the FWCS could act as the potential source of heavy metal contamination. These findings suggest that flotation wastes of copper slag (FWCS) can be readily utilised as cement raw material due to its availability in large quantities at low cost with the further significant benefits for waste management/environmental practices of the FWCS and the reduced production and processing costs for cement raw materials. PMID:18384950

Alp, I; Deveci, H; Süngün, H

2008-11-30

16

Cementation process for minerals recovery from Salton Sea geothermal brines  

SciTech Connect

The potential for minerals recovery from a 1000-MWe combined geothermal power and minerals recovery plant in the Salton Sea is examined. While the possible value of minerals recovered would substantially exceed the revenue from power production, information is insufficient to carry out a detailed economic analysis. The recovery of precious metals - silver, gold, and platinum - is the most important factor in determining the economics of a minerals recovery plant; however, the precious metals content of the brines is not certain. Such a power plant could recover 14 to 31% of the US demand for manganese and substantial amounts of zinc and lead. Previous work on minerals extraction from Salton Sea brines is also reviewed and a new process, based on a fluidized-bed cementation reaction with metallic iron, is proposed. This process would recover the precious metals, lead, and tin present in the brines.

Maimoni, A.

1982-01-26

17

Carbon dioxide capture from a cement manufacturing process  

DOEpatents

A process of manufacturing cement clinker is provided in which a clean supply of CO.sub.2 gas may be captured. The process also involves using an open loop conversion of CaO/MgO from a calciner to capture CO.sub.2 from combustion flue gases thereby forming CaCO.sub.3/CaMg(CO.sub.3).sub.2. The CaCO.sub.3/CaMg(CO.sub.3).sub.2 is then returned to the calciner where CO.sub.2 gas is evolved. The evolved CO.sub.2 gas, along with other evolved CO.sub.2 gases from the calciner are removed from the calciner. The reactants (CaO/MgO) are feed to a high temperature calciner for control of the clinker production composition.

Blount, Gerald C. (North Augusta, SC); Falta, Ronald W. (Seneca, SC); Siddall, Alvin A. (Aiken, SC)

2011-07-12

18

Characterization of vapor phase mercury released from concrete processing with baghouse filter dust added cement.  

PubMed

The fate of mercury (Hg) in cement processing and products has drawn intense attention due to its contribution to the ambient emission inventory. Feeding Hg-loaded coal fly ash to the cement kiln introduces additional Hg into the kiln's baghouse filter dust (BFD), and the practice of replacing 5% of cement with the Hg-loaded BFD by cement plants has recently raised environmental and occupational health concerns. The objective of this study was to determine Hg concentration and speciation in BFD as well as to investigate the release of vapor phase Hg from storing and processing BFD-added cement. The results showed that Hg content in the BFD from different seasons ranged from 0.91-1.44 mg/kg (ppm), with 62-73% as soluble inorganic Hg, while Hg in the other concrete constituents were 1-3 orders of magnitude lower than the BFD. Up to 21% of Hg loss was observed in the time-series study while storing the BFD in the open environment by the end of the seventh day. Real-time monitoring in the bench system indicated that high temperature and moisture can facilitate Hg release at the early stage. Ontario Hydro (OH) traps showed that total Hg emission from BFD is dictated by the air exchange surface area. In the bench simulation of concrete processing, only 0.4-0.5% of Hg escaped from mixing and curing BFD-added cement. A follow-up headspace study did not detect Hg release in the following 7 days. In summary, replacing 5% of cement with the BFD investigated in this study has minimal occupational health concerns for concrete workers, and proper storing and mixing of BFD with cement can minimize Hg emission burden for the cement plant. PMID:24444016

Wang, Jun; Hayes, Josh; Wu, Chang-Yu; Townsend, Timothy; Schert, John; Vinson, Tim; Deliz, Katherine; Bonzongo, Jean-Claude

2014-02-18

19

STEP cement: Solar Thermal Electrochemical Production of CaO without CO(2) emission.  

PubMed

New molten salt chemistry allows solar thermal energy to drive calcium oxide production without any carbon dioxide emission. This is accomplished in a one pot synthesis, and at lower projected cost than the existing cement industry process, which after power production, is the largest contributor to anthropogenic greenhouse gas emissions. PMID:22540130

Licht, Stuart; Wu, Hongjun; Hettige, Chaminda; Wang, Baohui; Asercion, Joseph; Lau, Jason; Stuart, Jessica

2012-04-26

20

Dynamic coherent light scattering by the cement during hydration process  

NASA Astrophysics Data System (ADS)

This paper is devoted to simulation of speckle field dynamics during coherent light scattering by cement surface in the process of hydration. Cement particles are represented by the spheres whose sizes and reflection indices are changing during the hydration process. The study of intensity fluctuations of scattered coherent radiation is suitable technique for the analysis both fast and slow processes of mineral binders hydration and forming polycrystalline structures in the process of hardening. The results of simulation are in good agreement with the experimental data.

Gorsky, M. P.; Maksimyak, P. P.

2013-12-01

21

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

SciTech Connect

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.

Schumacher, Katja; Sathaye, Jayant

1999-07-01

22

Glass recycling in cement production--an innovative approach.  

PubMed

An innovative approach of using waste glass in cement production was proposed and tested in a laboratory and cement production plant. The laboratory characterization of 32 types of glass show that the chemical composition of glass does not vary significantly with its color or origin but depends on its application. The alkali content of glass, a major concern for cement production varies from 0 to 22%. For the glass bottles mainly found in Hong Kong waste glasses, the alkali content (Na2O) ranges from 10 to 19% with an average around 15%. There is no significant change of the SO2 content in the gas exhaust of the rotary kiln when about 1.8 t/h of glass bottles were loaded along with the 280-290 t/h raw materials. The content of NOx, mainly depends on the temperature of the kiln, does not show significant change either. The SO3 content of the clinker is comparable with that obtained without the loading of glass. The alkaline content shows a slight increase but still within three times the standard deviation obtained from the statistical data of the past year. The detailed analysis of the quality of the cement product shows that there is not any significant impact of glass for the feeding rate tested. PMID:12365777

Chen, Guohua; Lee, Harry; Young, King Lun; Yue, Po Lock; Wong, Adolf; Tao, Thomas; Choi, Ka Keung

2002-01-01

23

Lightweight concrete production with low Portland cement consumption  

Microsoft Academic Search

The building industry has widespread social, economic and environmental impacts. Considering the materials used, such impacts depend on the production of concrete, since it is the most consumed material and its properties are associated with the consumption of Portland cement, which represents a significant part of CO2 emissions from this sector. This project studied the utility of recycled tire rubber

Fernando Pelisser; Airton Barcelos; Diego Santos; Michael Peterson; Adriano Michael Bernardin

24

Evaluation of cement production using a pressurized fluidized-bed combustor  

SciTech Connect

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.

DeLallo, M.; Eshbach, R.

1994-01-01

25

Utilization of borogypsum as set retarder in Portland cement production  

Microsoft Academic Search

Boron ores are used in the production of various boron compounds such as boric acid, borax and boron oxide. Boric acid is produced by reacting colemanite(2CaO·3B2O3·5H2O) with sulphuric acid and a large quantity of borogypsum is formed during this production. This waste causes various environmental problems when discharged directly to the environment. Portland cement is the most important material in

Recep Boncukcuo?lu; M. Tolga Y?lmaz; M. Muhtar Kocakerim; Vahdettin Tosuno?lu

2002-01-01

26

[Comparison of fixation effects of heavy metals between cement rotary kiln co-processing and cement solidification/stabilization].  

PubMed

Both cement rotary kiln co-processing hazardous wastes and cement solidification/stabilization could dispose heavy metals by fixation. Different fixation mechanisms lead to different fixation effects. The same amount of heavy metal compounds containing As, Cd, Cr, Cu, Pb, Zn were treated by the two kinds of fixation technologies. GB leaching test, TCLP tests and sequential extraction procedures were employed to compare the fixation effects of two fixation technologies. The leached concentration and chemical species distribution of heavy metals in two grounded mortar samples were analyzed and the fixation effects of two kinds of technologies to different heavy metals were compared. The results show the fixation effect of cement rotary kiln co-processing technology is better than cement solidification/stabilization technology to As, Pb, Zn. Calcinations in cement rotary kiln and then hydration help As, Pb, Zn contained in hazardous wastes transform to more steady chemical species and effectively dispose these heavy metals compounds. Cr3+ is liable to be converted to much more toxic and more mobile Cr6+ state in cement rotary kiln. And so Cr wastes are more fit for treatment by cement solidification/stabilization technology. The work could provide a basis when choosing disposal technologies for different heavy metals and be helpful to improve the application and development of cement rotary kiln co-processing hazardous wastes. PMID:18637375

Zhang, Jun-li; Liu, Jian-guo; Li, Cheng; Jin, Yi-ying; Nie, Yong-feng

2008-04-01

27

Fractal model for simulating the space-filling process of cement hydrates and fractal dimensions of pore structure of cement-based materials  

Microsoft Academic Search

A fractal model is established for simulating the space-filling process of cement hydrates in cement paste. Based on this model, it is predicted that the fractal dimension D of the pore structure of hardened cement paste (hcp) is between 0 and 3, and that the water-to-cement ratio, degree of hydration of cement, and the addition of pozzolanic materials will affect

X. Ji; S. Y. N. Chan; N. Feng

1997-01-01

28

Processing of high-performance fiber-reinforced cement-based composites  

Microsoft Academic Search

High-performance fiber-reinforced cement-based composites (HPFRCC) are characterized by their high elastic limit and strain hardening and a progressive multiple cracking type of response to mechanical loading. The parameters that influence the performance of such composites include: fiber type(s), matrix properties and processing. Processing can substantially influence fiber dispersion, quality of performance and cost of production. In spite of its importance,

Katherine G. Kuder; Surendra P. Shah

2010-01-01

29

Hydration process in Portland cement blended with activated coal gangue  

Microsoft Academic Search

This paper deals with the hydration of a blend of Portland cement and activated coal gangue in order to determine the relationship\\u000a between the degree of hydration and compressive strength development. The hydration process was investigated by various means:\\u000a isothermal calorimetry, thermal analysis, non-evaporable water measurement, and X-ray diffraction analysis. The results show\\u000a that the activated coal gangue is a

Xian-ping Liu; Pei-ming Wang; Min-ju Ding

2011-01-01

30

Potential use of pyrite cinders as raw material in cement production: results of industrial scale trial operations.  

PubMed

Pyrite cinders, which are the waste products of sulphuric acid manufacturing plants, contain hazardous heavy metals with potential environmental risks for disposal. In this study, the potential use of pyrite cinders (PyCs) as iron source in the production of Portland cement clinker was demonstrated at the industrial scale. The chemical and mineralogical analyses of the PyC sample used in this study have revealed that it is essentially a suitable raw material for use as iron source since it contains >87% Fe(2)O(3) mainly in the form of hematite (Fe(2)O(3)) and magnetite (Fe(3)O(4)). The samples of the clinkers produced from PyC in the industrial scale trial operation of 6 months were tested for the conformity of their chemical composition and the physico-mechanical performance of the resultant cement products. The data were compared with the clinker products of the iron ore, which is used as the raw material for the production Portland cement clinker in the plant. The chemical compositions of all the clinker products of PyC appeared to conform to those of the iron ore clinker, and hence, a Portland cement clinker. The mechanical performance of the mortars prepared from the PyC clinker was found to be consistent with those of the industrial cements e.g. CEM I type cements. It can be inferred from the leachability tests (TCLP and SPLP) that PyC could be a potential source of heavy metal pollution while the mortar samples obtained from the PyC clinkers present no environmental problems. These findings suggest that the waste pyrite cinders can be readily used as iron source for the production of Portland cement. The availability of PyC in large quantities at low cost provides further significant benefits for the management/environmental practices of these wastes and for the reduction of mining and processing costs of cement raw materials. PMID:19100685

Alp, I; Deveci, H; Yazici, E Y; Türk, T; Süngün, Y H

2009-07-15

31

Feasibility of using reject fly ash in cement-based stabilization/solidification processes  

SciTech Connect

Stabilization/solidification (s/s) has been routinely used for the final treatment of hazardous wastes prior to land disposal. These processes involve adding one or more solidifying reagents into the waste to transform it into a monolithic solid with improved structural integrity. Cement-based systems with partial replacement by pulverized fuel ash (PFA) have been widely used to minimize leaching of contaminants from hazardous wastes. The finer fraction of PFA ({lt}45 {mu} m, fine fly ash, MA), produced by passing the raw ash through a classifying process is commonly used in s/s processes. Low-grade fly ash is rejected (rFA) from the ash classifying process, and is largely unused due to high carbon content and large particle size but represents a significant proportion of PFA. This paper presents experimental results of a study that has assessed the feasibility of using rFA in the cement-based s/s of a synthetic heavy metal waste. Results were compared to mixes containing fFA. The strength results show that cement-based waste forms with rFA replacement are suitable for disposal at landfill and that the addition of heavy metal sludge can increase the degree of hydration of fly ash and decrease the porosity of samples. Adding Ca(OH){sub 2} and flue gas desulphurization sludge reduces the retarding effect of heavy metals on strength development. The results of the Toxicity Characteristic Leaching Procedure and Dynamic Leach Test show that rFA can be used in cement-based s/s wastes without compromising performance of the product.

Poon, C.S.; Qiao, X.C.; Cheeseman, C.R.; Lin, Z.S. [Hong Kong Polytechnic University, Kowloon (China). Dept. of Civil & Structural Engineering

2006-01-15

32

DEVELOPMENT OF A POLYMERIC CEMENTING AND ENCAPSULATING PROCESS FOR MANAGING HAZARDOUS WASTES  

EPA Science Inventory

A process using polymeric materials to cement and encapsulate dry hazardous waste was researched, developed, and evaluated. The process involves cementing particulates of waste into 500 to 1000 pound agglomerates, and then fusing a plastic jacket onto the agglomerate surfaces, th...

33

ASBESTOS-CEMENT PRODUCTS IN CONTACT WITH DRINKING WATER: SEM OBSERVATIONS  

EPA Science Inventory

In studying the health effects of asbestos fibers ingested in drinking water it is important to know whether water can corrode the surface of asbestos-cement products to facilitate the release of the fibers to the water. Also, in the case of asbestos-cement pipe, it is important ...

34

An analysis of the properties of Portland limestone cements and concrete  

Microsoft Academic Search

In this paper the main factors affecting the properties of Portland limestone cements are discussed while the hydration behavior of limestone cements is examined. In addition, the intergrinding process, concerning the production of the limestone cements, is studied. Finally the properties and the behavior of limestone cement concrete as well as the corrosion behavior of limestone cement mortar are investigated.

S Tsivilis; E Chaniotakis; G Kakali; G Batis

2002-01-01

35

INFLUENCE OF TECHNOLOGICAL FACTORS ON FOAM CEMENT CONCRETE FORMATION MIXTURES AND PRODUCT PROPERTIES  

Microsoft Academic Search

In this paper, 250–500 kg\\/m density autoclave hardened foam cement concrete production technology influence on some of its properties made using Portland cement is discussed. Raw materials composition is given in Table 1.Foam for the production of good quality foam concrete products should meet the following requirements: 1) be stable and mechanically strong, because it should hold the foam concrete

A. Laukaitis

1997-01-01

36

The use of calcium phosphate cement in vertebroplasty of the base of odontoid process.  

PubMed

The authors describe the use of bone cement containing calcium phosphate for vertebroplasty of the cavity in the base of odontoid process. A 23-year-old female patient was operated on by incision in lateral cervical area (anterior open access). After a blunt dissection, the working cannula (Kyphon) was introduced under fluoroscopic guidance through the C2 vertebral body to the cavity in the base of the odontoid process. Intraoperatively, biopsy of the lesion was taken and histo-pathological examination excluded the presence of neoplasm. The cavity, presumably haemangioma, was successfully filled with calcium phosphate bone cement KyphOsTM FS (Ky-phon). The proper filling without paravertebral cement leak was confirmed by postoperative computed tomography (CT). The CT and magnetic resonance imaging performed 9 months after the procedure showed that cement was still present in the cavity. This is the first use of calcium phosphate cement to conduct the vertebroplasty of C2 vertebra. PMID:24375006

Zapa?owicz, Krzysztof; Wojdyn, Maciej; Zieli?ski, Krzysztof W?odzimierz; Snopkowska-Wiaderna, Dorota

2013-01-01

37

Environmental Considerations of Selected Energy Conserving Manufacturing Process Options: Volume X. Cement Industry Report.  

National Technical Information Service (NTIS)

This study assesses the likelihood of new process technology and new practices being introduced by energy intensive industries and explores the environmental impacts of such changes. Volume 10 deals with the cement industry and examines four options: (1) ...

1976-01-01

38

Utilization of separator bag filter dust for high early strength cement production  

Microsoft Academic Search

This paper presents the feasibility of incorporating ultra-fine particles collected in the separator bag filter during the process of manufacturing cement (SBFC) as an substitution material for cement. Approximately 2.5% of SBFC is produced during OPC manufacturing process. Also, the average size of SBFC particles is about 5?m, the average size of OPC particles is about 14?m. This method does

Kwang Ho Sho; Sang Joon Park; Yong Jic Kim; Gun Cheol Lee; Kyoung Min Kim

2011-01-01

39

In situ monitoring of the hydration process of K-PS geopolymer cement with ESEM  

SciTech Connect

Environmental scanning electron microscope (ESEM) was used to in situ quantitatively study the hydration process of K-PS geopolymer cement under an 80% RH environment. An energy dispersion X-ray analysis (EDXA) was also employed to distinguish the chemical composition of hydration product. The ESEM micrographs showed that metakaolin particles pack loosely at 10 min after mixing, resulting in the existence of many large voids. As hydration proceeds, a lot of gels were seen and gradually precipitated on the surfaces of these particles. At later stage, these particles were wrapped by thick gel layers and their interspaces were almost completely filled. The corresponding EDXA results illustrated that the molar ratios of K/Al increase while Si/Al decrease with the development of hydration. As a result, the molar ratios of K/Al and Si/Al of hydration products at an age of 4 h amounted to 0.99 and 1.49, respectively, which were close to the theoretical values (K/Al=1.0, Si/Al=1.0 for K-PS geopolymer cement paste). In addition, well-developed crystals could not been found at any ages; instead, spongelike amorphous gels were always been observed.

Sun Wei; Zhang Yunsheng; Lin Wei; Liu Zhiyong

2004-06-01

40

The use of Devonian oil shales in the production of portland cement  

SciTech Connect

The Lafarge Corporation operates a cement plant at Alpena, Michigan in which Antrim shale, a Devonian oil shale, is used as part of the raw material mix. Using this precedent the authors examine the conditions and extent to which spent shale might be utilized in cement production. They conclude that the potential is limited in size and location but could provide substantial benefit to an oil shale operation meeting these criteria.

Schultz, C.W.; Lamont, W.E. [Alabama Univ., University, AL (United States); Daniel, J. [Lafarge Corp., Alpena, MI (United States)

1991-12-31

41

Comparison of the fixation effects of heavy metals by cement rotary kiln co-processing and cement based solidification/stabilization.  

PubMed

Cement rotary kiln co-processing of hazardous wastes and cement based solidification/stabilization could both immobilize heavy metals. The different retention mechanisms of the two technologies lead to different fixation effects of heavy metals. The same amount of heavy metal compounds were treated by the two types of fixation technologies. Long-term leaching test (160 days), the maximum availability leaching test (NEN 7341) and a modified three-step sequential extraction procedure, proposed by the Commission of the European Communities Bureau of Reference (BCR) were employed to compare the fixation effects of the two fixation technologies. The leaching concentrations in NEN 7341 and long-term leaching tests were compared with identification standard for hazardous wastes (GB5085.3-1996) and drinking water standard (GB5749-2005). The results indicate that the leaching concentrations of the long-term leaching test and NEN 7341 test were lower than the regulatory limits and the leached ratios were small. Both cement based solidification/stabilization and cement rotary kiln co-processing could effectively fix heavy metals. Calcination in a cement rotary kiln and the following hydration that follows during cement application could fix As, Cd, Pb and Zn more effectively and decrease the release to the environment. Cement solidification/stabilization technology has better effect in immobilizing Cr and Ni. Cr wastes are more fitful to be treated by cement solidification/stabilization. PMID:19091467

Zhang, Junli; Liu, Jianguo; Li, Cheng; Jin, Yiying; Nie, Yongfeng; Li, Jinhui

2009-06-15

42

HAZARDOUS WASTE COMBUSTION IN INDUSTRIAL PROCESSES: CEMENT AND LIME KILNS  

EPA Science Inventory

The report summarizes the results of several studies relating to hazardous waste combustion in cement and lime kilns. The tests included in the study are four kilns tested by the U.S. Environmental Protection Agency, four kilns tested by State agencies or the kiln operator, two C...

43

Cement and concrete  

NASA Astrophysics Data System (ADS)

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.

Corley, Gene; Haskin, Larry A.

44

Cement and concrete  

NASA Technical Reports Server (NTRS)

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.

Corley, Gene; Haskin, Larry A.

1992-01-01

45

Sculpting with Cement.  

ERIC Educational Resources Information Center

Cement offers many creative possibilities for school art programs. Instructions are given for sculpting with fiber-cement and sand-cement, as well as for finishing processes and the addition of color. Safety is stressed. (IS)

Olson, Lynn

1983-01-01

46

The effect of processing on the bond and interfaces in steel fiber reinforced cement composites  

Microsoft Academic Search

The object of the present work was to study the influences that processing may have on the pullout resistance of a steel fiber from a normal cementitious matrix, consisting of portland cement binder cast as paste or mortars with varying sand content. In order to determine the mechanisms by which the processing affects the pull-out resistance, the nature of the

S. Igarashi; A. Bentur; S. Mindess

1996-01-01

47

Portland cement for bone tissue engineering: Effects of processing and metakaolin blends.  

PubMed

The need for a suitable scaffolding material for load bearing bone tissue engineering still has yet to be met satisfactorily. In this study, Portland cement and Portland cement/metakaolin (MK) blends were processed to render them biologically and mechanically suitable for such application. Portland cement was mixed with MK at different ratios. The slurries were hydrated under atmospheric (noncarbonated samples) and high-CO? conditions (carbonated samples). The mechanical properties were characterized via compressive tests. The bioactivity was analyzed in a simulated body fluid solution. Scanning electron microscopy and energy dispersive spectroscopy were used to evaluate sample morphology and chemistry. The cytocompatibility (direct contact assay, MTT test, and alkaline phosphatase activity) was tested using human osteoblast-like cells. Cell responses were observed via conventional and electron microscopy. The results showed that the implementation of MK did not significantly influence the mechanical properties. All the samples evidenced bioactive behavior. Cell experiments confirmed a highly cytotoxic response to the noncarbonated specimens. The introduction of MK as well as the CO? pretreatment significantly improved the cytocompatibility of the specimens. These results show that properly processed Portland cement and Portland cement/MK blends could present suitable properties for the development of load-bearing scaffolding structures in bone tissue-engineering applications. PMID:21648058

Gallego-Perez, Daniel; Higuita-Castro, Natalia; Quiroz, Felipe García; Posada, Olga M; López, Luis E; Litsky, Alan S; Hansford, Derek J

2011-08-01

48

Towards optimization of the silanization process of hydroxyapatite for its use in bone cement formulations.  

PubMed

The aim of this work was to provide some fundamental information for optimization of silanization of hydroxyapatite intended for bone cement formulations. The effect of 3-(trimethoxysilyl) propyl methacrylate (MPS) concentration and solvent system (acetone/water or methanol/water mixtures) during HA silanization was monitored by X-ray diffraction (XRD), FTIR spectroscopy and EDX analysis. The effect of silanized HA on the mechanical properties of acrylic bone cements is also reported. It was found that the silanization process rendered hydroxyapatite with lower crystallinity compared to untreated HA. Through EDX, it was observed that the silicon concentration in the HA particles was higher for acetone-water than that obtained for methanol-water system, although the mechanical performance of cements prepared with these particles exhibited the opposite behavior. Taking all these results together, it is concluded that methanol-water system containing MPS at 3wt.% provides the better results during silanization process of HA. PMID:24857478

Cisneros-Pineda, Olga G; Herrera Kao, Wilberth; Loría-Bastarrachea, María I; Veranes-Pantoja, Yaymarilis; Cauich-Rodríguez, Juan V; Cervantes-Uc, José M

2014-07-01

49

Chrome free basic bricks-a determining factor in cement production  

Microsoft Academic Search

A considerable section of every cement rotary kiln is lined with basic bricks. They are supposed to protect the steel shell against extensive heat, severe chemical attack and mechanical stress. A combination of specific raw materials with a matching binding mechanism is chosen by various refractory producers to manufacture well performing products. Each brick supplier advertises his materials as the

H.-J. Schmidt

1998-01-01

50

Production of cement clinkers from municipal solid waste incineration (MSWI) fly ash  

Microsoft Academic Search

This communication reports the laboratory scale study on the production of cement clinkers from two types of municipal solid waste incineration fly ash (MSW ash) samples. XRD technique was used to monitor the phase formation during the burning of the raw mixes. The amount of trace elements volatilized during clinkerization and hydration, as well as leaching behaviours of the clinkers

Nabajyoti Saikia; Shigeru Kato; Toshinori Kojima

2007-01-01

51

Use of Ceramic Material (cement Clinker) for the Production of Biodiesel  

NASA Astrophysics Data System (ADS)

Biodiesel is a renewable liquid fuel made from natural, renewable biological sources such as edible and non edible oils. Over the last years, biodiesel has gained more market due to its benefits and because it appears as the natural substitute for diesel. Reasons for growing interest in biodiesel include its potential for reducing noxious emissions, potential contributions to rural economic development, as an additional demand center for agricultural commodities, and as a way to reduce reliance on foreign oil. Biodiesel was prepared from soybean oil by transesterification with methanol in the presence of cement clinker. Cement clinker was examined as a catalyst for a conversion of soybean oil to fatty acid methyl esters (FAMEs). It can be a promising heterogeneous catalyst for the production of biodiesel fuels from soybean oil because of high activity in the conversion and no leaching in the transesterification reaction. The reaction conditions were optimized. A study for optimizing the reaction parameters such as the reaction temperature, and reaction time, was carried out. The catalyst cement clinker composition was characterized by XRF. The results demonstrate that the cement clinker shows high catalytic performance & it was found that the yield of biodiesel can reach as high as 84.52% after 1 h reaction at 65°C, with a 6:1 molar ratio of methanol to oil, 21 wt% KOH/cement clinker as catalyst.

Soni, Sunny; Agarwal, Madhu

52

Biphasic products of dicalcium phosphate-rich cement with injectability and nondispersibility.  

PubMed

In this study, a calcium phosphate cement was developed using tetracalcium phosphate and surface-modified dicalcium phosphate anhydrous (DCPA). This developed injectable bone graft substitute can be molded to the shape of the bone cavity and set in situ through the piping system that has an adequate mechanical strength, non-dispersibility, and biocompatibility. The materials were based on the modified DCPA compositions of calcium phosphate cement (CPC), where the phase ratio of the surface-modified DCPA is higher than that of the conventional CPC for forming dicalcium phosphate (DCP)-rich cement. The composition and morphology of several calcium phosphate cement specimens during setting were analyzed via X-ray diffractometry and transmission electron microscopy coupled with an energy dispersive spectroscopy system. The compressive strength of DCP-rich CPCs was greater than 30MPa after 24h of immersion in vitro. The reaction of the CPCs produced steady final biphasic products of DCPs with apatite. The composites of calcium phosphate cements derived from tetracalcium phosphate mixed with surface-modified DCPA exhibited excellent mechanical properties, injectability, and interlocking forces between particles, and they also featured nondispersive behavior when immersed in a physiological solution. PMID:24863195

Ko, Chia-Ling; Chen, Jian-Chih; Hung, Chun-Cheng; Wang, Jen-Chyan; Tien, Yin-Chun; Chen, Wen-Cheng

2014-06-01

53

Pond ash -- A potential reactive raw material in the black meal process of cement manufacture by vertical shaft kiln (VSK) technology  

SciTech Connect

Pond ash from thermal power plants serves as a reactive raw material in the black meal process of cement manufacture. Plant scale trials in a 50 TPD VSK plant have shown encouraging results in terms of quality improvement, energy conservation and enhanced production. Clinker produced was easy to grind resulting in saving of grinding energy.

Singh, N.B.; Bhattacharjee, K.N.; Shukla, A.K. [Univ. of Gorakhpur (India). Dept. of Chemistry] [Univ. of Gorakhpur (India). Dept. of Chemistry

1995-04-01

54

Crystal chemistry of the high temperature product of transformation of cement-asbestos.  

PubMed

In this work, the high-temperature inertization product of a representative batch of samples of cement-asbestos (CA) from different localities in Italy have been characterized with a multidisciplinary approach. All the raw CA samples were heated at 1200°C for 15 min. After firing, they underwent a series of solid state reactions leading to global structural changes of the matrix. Effects of annealing time and temperature on the crystallization kinetics were thoroughly investigated. Both factors acted in favour of equilibrium. Three classes of CA were identified with the aid of phase diagrams and of specific plots relating chemical and mineralogical parameters. This result was considered of importance in view of the potential use of transformed cement-asbestos as a secondary raw material. In principle, the content of CA packages removed from the environment and their corresponding heat-treated products can be classified simply using XRF. This method allows for the selection of appropriate fractions in function of the most suitable recycling solution adopted. Samples belonging to the class called larnite-rich, turned out to be of great interest as possible candidate for substituting a fraction of cement in many building materials and innovative green cement productions. PMID:23380447

Viani, Alberto; Gualtieri, Alessandro F; Pollastri, Simone; Rinaudo, Caterina; Croce, Alessandro; Urso, Giancarlo

2013-03-15

55

ENVIRONMENTAL CONSIDERATIONS OF SELECTED ENERGY CONSERVING MANUFACTURING PROCESS OPTIONS: VOLUME X. CEMENT INDUSTRY REPORT  

EPA Science Inventory

This study assesses the likelihood of new process technology and new practices being introduced by energy intensive industries and explores the environmental impacts of such changes. Volume 10 deals with the cement industry and examines four options: (1) suspension preheater, (2)...

56

INDUSTRIAL PROCESS PROFILES FOR ENVIRONMENTAL USE: CHAPTER 21. THE CEMENT INDUSTRY  

EPA Science Inventory

The catalog of Industrial Process Profiles for Environmental Use was developed as an aid in defining the environmental impacts of industrial activity in the United States. Entries for each industry are in consistent format and form separate chapters of the study. The cement indus...

57

ELIMINATION OF WATER POLLUTION BY RECYCLING CEMENT PLANT KILN DUST  

EPA Science Inventory

Excessive amounts of alkalies can have deleterious effects upon the process of cement manufacture and the product. Normally much of the alkali present in cement raw materials is volatilized in the cement kiln and condenses on the particles of kiln dust which are carried out of th...

58

Silicon production process evaluations  

NASA Technical Reports Server (NTRS)

Chemical engineering analyses involving the preliminary process design of a plant (1,000 metric tons/year capacity) to produce silicon via the technology under consideration were accomplished. Major activities in the chemical engineering analyses included base case conditions, reaction chemistry, process flowsheet, material balance, energy balance, property data, equipment design, major equipment list, production labor and forward for economic analysis. The process design package provided detailed data for raw materials, utilities, major process equipment and production labor requirements necessary for polysilicon production in each process.

1982-01-01

59

Influence of mixture ratio and pH to solidification/stabilization process of hospital solid waste incineration ash in Portland cement.  

PubMed

Solidification/stabilization (S/S) is an established utilization technology to treat hazardous wastes. This research explored the influence of pH (3-12) on the immobilization of heavy metals present in five mixtures of hospital solid waste incinerator ash and Portland cement, following two different processes of waste solidification/stabilization (cement hydration and granulation). In general, cement hydration process resulted in more stable products than granulation process. A high ash content in the mixture with Portland cement (60wt%) resulted in the highest immobilization of Pb(2+) and Cu(2+), while a low ash content in the mixture (10wt%) resulted in the lowest leachability of Zn(2+). When ash and Portland cement was mixed in equal proportions (50wt%) the highest encapsulation was observed for Ni(2+), Cd(2+) and Cr(3+). Neutral and weak alkaline pH values within the range pH=7-8 resulted in the lowest leachability of the monitored heavy metals. PMID:24997895

Sobiecka, Elzbieta; Obraniak, Andrzej; Antizar-Ladislao, Blanca

2014-09-01

60

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

PubMed

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. PMID:20708915

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

2011-01-01

61

Cement invasion  

SciTech Connect

Damage from cement and cement filtrate has been a much discussed subject since set-through-and-perforate completions were first used. Historically, much of the discussion was similar to that for rotary drilling and drilling mud - it would be nice to prevent all damage, but in the real world, some damage must be tolerated to allow the operator to reap the benefits of cementing. The principal perceived formation damage due to cement invasion is seen by the operator as reducing production. The pure idealist requires full potential production under all alternatives, and would to complete all oil and gas wells free of any formation damage. The more practical idealist holds that damage would result in lower production with the completion method he prefers should be prevented. The pragmatic operator compares the cost of preventing damage to the cost of correcting the damage. Even an extremely high damage ratio is academic if the planned stimulation treatment eliminates the influence the cement invasion might have on production. Formations with permeability high enough to yield economical production without some sort of stimulation or cleanup treatment are unlikely to be subject to significant cement filtrate damage.

Sutton, D.L.

1988-09-01

62

75 FR 453 - FLSMidth, Inc., Cement Division, Product Engineering, Including On-Site Leased Workers of Aerotek...  

Federal Register 2010, 2011, 2012, 2013

...TA-W-72,048] FLSMidth, Inc., Cement Division, Product Engineering, Including On-Site Leased Workers of Aerotek Contract Engineering, Allied Personnel Services, Eastern Engineering, Hobbie Professional Services, Mccallion Staffing...

2010-01-05

63

New processing approaches in calcium phosphate cements and their applications in regenerative medicine.  

PubMed

The key feature of calcium phosphate cements (CPCs) lies in the setting reaction triggered by mixing one or more solid calcium phosphate salts with an aqueous solution. Upon mixture, the reaction takes place through a dissolution-precipitation process which is macroscopically observed by a gradual hardening of the cement paste. The precipitation of hydroxyapatite nanocrystals at body or room temperature, and the fact that those materials can be used as self-setting pastes, have for many years been the most attractive features of CPCs. However, the need to develop materials able to sustain bone tissue ingrowth and be capable of delivering drugs and bioactive molecules, together with the continuous requirement from surgeons to develop more easily handling cements, has pushed the development of new processing routes that can accommodate all these requirements, taking advantage of the possibility of manipulating the self-setting CPC paste. It is the goal of this paper to provide a brief overview of the new processing developments in the area of CPCs and to identify the most significant achievements. PMID:20123046

Ginebra, M P; Espanol, M; Montufar, E B; Perez, R A; Mestres, G

2010-08-01

64

Physical and mechanical properties of cement-based products containing incineration bottom ash.  

PubMed

This paper presents the results of a wider experimental programme conducted in the framework of the NNAPICS ("Neural Network Analysis for Prediction of Interactions in Cement/Waste Systems") project funded by the European Commission and a number of industrial partners under Brite-EuRamIII. Based on the fact that bottom ashes from waste incineration are classified as non-hazardous wastes according to the European Waste Catalogue, the aim of the present work was to investigate the feasibility of addressing the potential use of such residues in cement-based mixtures. This issue was suggested by the analysis of the properties of different bottom ashes coming from Italian municipal and hospital solid waste incinerators, which showed a chemical composition potentially suitable for such applications. Different mixes were prepared by blending bottom ash with ordinary Portland cement in different proportions and at different water dosages. The solidified products were tested for setting time and bulk density, unconfined compressive strength and evaporable water content at different curing times. The results of the experimental campaign were analysed through a statistical procedure (analysis of variance), in order to investigate the effect of mixture composition (waste replacement level and water dosage) on the product properties. PMID:12623089

Filipponi, P; Polettini, A; Pomi, R; Sirini, P

2003-01-01

65

Production of a calcium silicate cement material from alginate impression material.  

PubMed

The purpose of this study was to synthesize biomaterials from daily dental waste. Since alginate impression material contains silica and calcium salts, we aimed to synthesize calcium silicate cement from alginate impression material. Gypsum-based investment material was also investigated as control. X-ray diffraction analyses revealed that although firing the set gypsum-based and modified investment materials at 1,200°C produced calcium silicates, firing the set alginate impression material did not. However, we succeeded when firing the set blend of pre-fired set alginate impression material and gypsum at 1,200°C. SEM observations of the powder revealed that the featured porous structures of diatomite as an alginate impression material component appeared useful for synthesizing calcium silicates. Experimentally fabricated calcium silicate powder was successfully mixed with phosphoric acid solution and set by depositing the brushite. Therefore, we conclude that the production of calcium silicate cement material is possible from waste alginate impression material. PMID:22864217

Washizawa, Norimasa; Narusawa, Hideaki; Tamaki, Yukimichi; Miyazaki, Takashi

2012-01-01

66

Environmental behavior of cement-based stabilized foundry sludge products incorporating additives.  

PubMed

A series of experiments were conducted to stabilize the inorganic and organic pollutants in a foundry sludge from a cast iron activity using Portland cement as binder and three different types of additives, organophilic bentonite, lime and coal fly ash. Ecotoxicological and chemical behavior of stabilized mixes of foundry sludge were analyzed to assess the feasibility to immobilize both types of contaminants, all determined on the basis of compliance leaching tests. The incorporation of lime reduces the ecotoxicity of stabilized mixes and enhances stabilization of organic pollutants obtaining better results when a 50% of cement is replaced by lime. However, the alkalinity of lime increases slightly the leached zinc up to concentrations above the limit set under neutral conditions by the European regulations. The addition of organophilic bentonite and coal fly ash can immobilize the phenolic compounds but are inefficient to reduce the ecotoxicity and mobility of zinc of final products. PMID:15177744

Ruiz, M C; Irabien, A

2004-06-18

67

Radioactive waste processing: Fixation in cements and bitumens. November 1973-February 1990 (A Bibliography from the NTIS data base). Report for November 1973-February 1990  

SciTech Connect

This bibliography contains citations concerning the fixation or solidification of radioactive wastes using cements, bitumens, or asphalts. Formulation, physical strength, degradation, and leachability of these materials are presented. Full scale production plants are described. Gaseous wastes, nitrate salts, borate salts, spent fuels, contaminated soils, sludges, and liquid wastes can be solidified in these materials. Vitrification processes for radioactive waste disposal are discussed in a separate bibliography. (Contains 217 citations fully indexed and including a title list.)

Not Available

1990-02-01

68

Silicon production process evaluations  

NASA Technical Reports Server (NTRS)

Engineering design of the third distillation column in the process was accomplished. The initial design is based on a 94.35% recovery of dichlorosilane in the distillate and a 99.9% recovery of trichlorosilane in the bottoms. The specified separation is achieved at a reflux ratio of 15 with 20 trays (equilibrium stages). Additional specifications and results are reported including equipment size, temperatures and pressure. Specific raw material requirements necessary to produce the silicon in the process are presented. The primary raw materials include metallurgical grade silicon, silicon tetrachloride, hydrogen, copper (catalyst) and lime (waste treatment). Hydrogen chloride is produced as by product in the silicon deposition. Cost analysis of the process was initiated during this reporting period.

1982-01-01

69

The investigation of basic processes of rapidly hardening wood-cement-water mixture with CO 2  

Microsoft Academic Search

The rapid hardening of wood-cement-water mixture in a carbon dioxide enriched environment\\u000a was investigated, by studying the development of carbonation degree and monitoring the phase changes\\u000a in the mixture. The carbonation reaction was a diffusion-controlled process. It occurred very\\u000a quickly in the first two minutes of reaction. After that, its rate decreased drastically, due to the\\u000a increasing difficulty of transporting reactants to

Hucheng Qi; Paul A. Cooper; Doug Hooton

2010-01-01

70

Laser-radiation scattering by cement in the process of hydration: simulation of the dynamics and experiment.  

PubMed

This paper discusses simulation of speckle-field dynamics during coherent light scattering by a cement surface in the process of hydration. Cement particles are represented by the spheres whose sizes and reflection indices are changing during the hydration process. The study of intensity fluctuations of scattered coherent radiation is a suitable technique for the analysis of both fast and slow processes of mineral binder hydration and formation of polycrystalline structures in the process of hardening. The results of simulation are in good agreement with the experimental data. PMID:22505102

Gorsky, M P; Maksimyak, P P; Maksimyak, A P

2012-04-01

71

75 FR 4423 - Notice Pursuant to the National Cooperative Research and Production Act of 1993-Portland Cement...  

Federal Register 2010, 2011, 2012, 2013

...the National Cooperative Research and Production Act of 1993--Portland Cement Association...the National Cooperative Research and Production Act of 1993, 15 U.S.C. 4301 et...Chemicals, Inc., Allentown, PA; LWB Refractories, York, PA; MikroPul,...

2010-01-27

72

In vitro biodurability of the product of thermal transformation of cement-asbestos.  

PubMed

To safely recycle the product of the thermal transformation of cement-asbestos as secondary raw material, its toxicity potential should be assessed by in vitro biodurability tests. In this work, the acellular in vitro biodurability of the products of transformation of cement-asbestos at 1200 °C (named KRY·AS) was tested using both inorganic and organic simulated lung fluids at pH 4.5. The dissolution kinetics were followed using chemical, mineralogical and microstructural analyses. The total dissolution time estimated from the experiments with inorganic HCl diluted solution is one order of magnitude higher than that determined from the experiments with buffered Gamble solution (253 days vs. 20 days). The key parameter determining the difference in dissolution rate turns out to be the solidus/liquidus ratio which prompts a fast saturation of the solution with monosilicic acid. The calculated dissolution rate constants showed that the biodurability in vitro of KRY·AS is much lower with respect to that of standard chrysotile asbestos (total estimated dissolution time of 20 days vs. 298 days, respectively). This proves a low potential toxicity of this secondary raw material. PMID:22257569

Gualtieri, Alessandro F; Viani, Alberto; Sgarbi, Giulia; Lusvardi, Gigliola

2012-02-29

73

The hydration products of Portland cement in the presence of tin(II) chloride  

SciTech Connect

The hydration products of Portland cement pastes cured using water containing tin(II) chloride have been compared with those using distilled water. In the latter case, the expected products - portlandite, ettringite and calcite - were observed. The X-ray diffraction patterns of the cement pastes cured in the presence of tin(II) chloride showed several additional peaks that have been attributed to the formation of calcium hydroxo-stannate, CaSn(OH){sub 6}, and Friedel's salt (tetracalcium aluminate dichloride-10-hydrate), Ca{sub 3}Al{sub 2}O{sub 6}{center_dot}CaCl{sub 2}{center_dot}10H{sub 2}O. The amount of portlandite formed was reduced in the presence of tin(II) chloride. Calcium hydroxo-stannate contains tin in the +IV oxidation state and equations are presented to account for the oxidation of Sn(II) to Sn(IV) preceding the formation of CaSn(OH){sub 6} and Friedel's salt.

Hill, J.; Sharp, J.H

2003-01-01

74

Assessment of the self-desiccation process in cemented mine backfills  

Microsoft Academic Search

During the placement of fine-grained cemented mine backfill, the high placement rates and low permeability often result in undrained self-weight loading conditions, when assessed in the conventional manner. However, hydration of the cement in the backfill results in a net volume reduction—the volume of the hydrated cement is less than the combined volume of the cement and water prior to

Matthew Helinski; M. Fahey; A. Fourie; Mostafa Ismail

2007-01-01

75

Butadiene production process overview.  

PubMed

Over 95% of butadiene is produced as a by-product of ethylene production from steam crackers. The crude C4 stream isolated from the steam cracking process is fed to butadiene extraction units, where butadiene is separated from the other C4s by extractive distillation. The amount of crude C4s produced in steam cracking is dependent on the composition of the feed to the cracking unit. Heavier feeds, such as naphtha, yield higher amounts of C4s and butadiene than do lighter feeds. Crackers using light feeds typically produce low quantities of C4s and do not have butadiene extraction units. Overall butadiene capacity is determined by ethylene cracker operating rates, the type of feed being cracked, and availability of butadiene extraction capacity. Global butadiene capacity is approximately 10.5 million metric tons, and global production is approximately 9 million metric tons [Chemical Marketing Associates, Inc. (CMAI), 2005 World Butadiene Analysis, Chemical Marketing Associates, Inc. (CMAI), 2005]. Crude C4s are traded globally, with the United States being the only significant net importer. Finished butadiene is also traded globally, with the largest exporters being Canada, Western Europe, Saudi Arabia and Korea. The largest net importers are Mexico, the United States and China. The global demand for butadiene is approximately 9 million metric tons [Chemical Marketing Associates, Inc. (CMAI), 2005 World Butadiene Analysis, Chemical Marketing Associates, Inc. (CMAI), 2005]. Production of styrene-butadiene rubber and polybutadiene rubber accounts for about 54% of global butadiene demand, with tire production being the single most important end use of butadiene synthetic rubbers. Other major butadiene derivatives are acrylonitrile-butadiene-styrene (ABS) and styrene butadiene latex (about 24% of demand combined). PMID:17324391

White, Wm Claude

2007-03-20

76

Elimination of water pollution by recycling cement plant kiln dust. Final report  

Microsoft Academic Search

Excessive amounts of alkalies can have deleterious effects upon the process of cement manufacture and the product. Normally much of the alkali present in cement raw materials is volatilized in the cement kiln and condenses on the particles of kiln dust which are carried out of the kiln by the combustion gases. Air pollution control devices, such as electrostatic precipitators

N. R. Greening; F. M. Miller; C. H. Weiss; H. Nagao

1976-01-01

77

Use of zeolite, coal bottom ash and fly ash as replacement materials in cement production  

Microsoft Academic Search

In this research, the effects of zeolite, coal bottom ash and fly ash as Portland cement replacement materials on the properties of cement are investigated through three different combinations of tests. These materials are substituted for Portland cement in different proportions, and physical properties such as setting time, volume expansion, compressive strength and water consistency of the mortar are determined.

F Canpolat; K Y?lmaz; M. M Köse; M Sümer; M. A Yurdusev

2004-01-01

78

A New CO2 Sequestration Process via Concrete Products Production  

Microsoft Academic Search

This paper investigates the possibility of using concrete building products to absorb carbon dioxide during their production and develop high early strength at the same time. Type 10 and Type 30 Portland cements were examined by their abilities to serve as CO2 absorbents when exposed to carbon dioxide with 100% and 25% concentrations, the former simulating the recovered CO2 and

Yixin Shao; Xudong Zhou; S. Monkman

2006-01-01

79

Environmental assessment of sewage sludge as secondary raw material in cement production--a case study in China.  

PubMed

A life cycle assessment was carried out to estimate the environmental impact of sewage sludge as secondary raw material in cement production. To confirm and add credibility to the study, uncertainty analysis was conducted. Results showed the impact generated from respiratory inorganics, terrestrial ecotoxicity, global warming, and non-renewable energy categories had an important contribution to overall environmental impact, due to energy, clinker, and limestone production stages. Also, uncertainty analysis results showed the technology of sewage sludge as secondary raw material in cement production had little or no effect on changing the overall environmental potential impact generated from general cement production. Accordingly, using the technology of sewage sludge as secondary raw material in cement production is a good choice for reducing the pressure on the environment from dramatically increased sludge disposal. In addition, increasing electricity recovery rate, choosing natural gas fired electricity generation technology, and optimizing the raw material consumption in clinker production are highly recommended to reduce the adverse effects on the environment. PMID:21288709

Hong, Jinglan; Li, Xiangzhi

2011-06-01

80

The transformation sequence of cement-asbestos slates up to 1200 degrees C and safe recycling of the reaction product in stoneware tile mixtures.  

PubMed

Cement-asbestos is the main asbestos containing material still found in most of the European countries such as Italy. Man- and weathering-induced degradation of the cement-asbestos slates makes them a source of dispersion of asbestos fibres and represents a priority cause of concern. This concern is the main prompt for the actual policy of abatement and disposal of asbestos containing materials in controlled wastes. An alternative solution to the disposal in dumping sites is the direct temperature-induced transformation of the cement-asbestos slates into non-hazardous mineral phases. This patented process avoids the stage of mechanical milling of the material before the treatment, which improves the reactivity of the materials but may be critical for the dispersion of asbestos fibres in working and life environment. For the first time, this paper reports the description of the reaction path taking place during the firing of cement-asbestos slates up to the complete transformation temperature, 1200 degrees C. The reaction sequence was investigated using different experimental techniques such as optical and electron microscopy, in situ and ex situ quali-quantitative X-ray powder diffraction. The understanding of the complex reaction path is of basic importance for the optimization of industrial heating processes leading to a safe recycling of the transformed product. For the recycling of asbestos containing materials, the Italian laws require that the product of the crystal chemical transformation of asbestos containing materials must be entirely asbestos-free, and should not contain more than 0.1 wt% fraction of the carcinogenic substances such as cristobalite. Moreover, if fibrous phases other than asbestos (with length to diameter ratio >3) are found, they must have a geometrical diameter larger than 3 microm. We have demonstrated that using an interplay of different experimental techniques, it is possible to safely verify the complete transformation of asbestos minerals in this temperature-induced process. The product of transformation of cement-asbestos (CATP) has a phase composition similar to that of a natural or a low temperature clinker with the exception of having a larger content of aluminium, iron and magnesium. This product can be safely recycled for the production of stoneware tile mixtures. The addition of 3-5 mass% of CATP does not bear significant variations to the standard parameters of white porcelain tile mixtures. PMID:17709183

Gualtieri, A F; Cavenati, C; Zanatto, I; Meloni, M; Elmi, G; Gualtieri, M Lassinantti

2008-04-01

81

An investigation into current production challenges facing the Libyan cement industry and the need for innovative total productive maintenance (TPM) strategy  

Microsoft Academic Search

Purpose – The purpose of this paper is to investigate maintenance and production problems in the cement industry in Libya, with particular emphasis on future implementation of total productive maintenance (TPM). Design\\/methodology\\/approach – The paper presents the use of case study approach of production data and history, field visits, a survey methodology using a detailed questionnaire with employees and interviews

Mustafa Graisa; Amin Al-Habaibeh

2011-01-01

82

Recent technologies and processes for enhanced safety in bitumen or cement solidification of Li\\/ml radwaste  

Microsoft Academic Search

SGN has more than 20 years of experience in the treatment of low and medium level radioactive wastes. SGN industrialized two major types of radwaste processes: bituminization and cement solidification. The R&D work on these two processes is discussed.

Tchemitcheff

1993-01-01

83

Processes for producing hydrocarbon products  

US Patent & Trademark Office Database

The present invention relates to processes for producing industrial products such as hydrocarbon products from non-polar lipids in a vegetative plant part. Preferred industrial products include alkyl esters which may be blended with petroleum based fuels.

2014-05-27

84

SEM/EDX characterization of the hydration products of belite cements from class C coal fly ash  

SciTech Connect

This paper presents the microscopic characterization of two types of fly ash belite cements and their hydration products by means of scanning electron microscopy, energy-dispersive X-ray microanalysis, and X-ray diffraction analysis. The cements were obtained from ASTM class C coal fly ash by the hydrothermal-calcination route in water (FABC-2-W) and NaOH 1M solution (FABC-2-N). The hydration was studied during a period of 180 days at 21{sup o}C and >95% RH. The results showed significant incorporation of aluminum (Al) into the C-S-H gel and other minor elements, with a presumable composition close to that of aluminum-tobermorite. The C-S-H composition of the FABC-2-W is more stable over the hydration time than that of the FABC-2-N cement. Portlandite is scarcely formed during hydration.

Goni, S.; Guerrero, A. [CSIC, Madrid (Spain)

2007-12-15

85

Middle Pleistocene carbonate-cemented colluvium in southern Poland: Its depositional processes, diagenesis and regional palaeoenvironmental significance  

NASA Astrophysics Data System (ADS)

A colluvial origin is postulated for the enigmatic relic mantle of immature, carbonate-cemented rudites on the bedrock slope of Kraków Highland, preserved in the area of Kwacza?a Gullies. The deposits comprise four sedimentary facies: (A) sporadic clast-supported openwork conglomerates; (B) predominant matrix-supported massive conglomerates, some with a coarse-tail normal grading; (C) subordinate sheets of parallel stratified and/or ripple cross-laminated fine-grained sandstones; and (D) local coarse-grained sandstones with gently inclined parallel stratification. The 230Th-U dating of sparry calcite cements points to the penultimate Odranian/Warthanian interglacial. The debris was derived from local bedrock, inferred to have been frost-shattered in permafrost conditions during the Odranian glacial. Colluvial resedimentation was triggered by the rapid change in environment conditions brought by early deglaciation. Dense-snow/slush flows and slush-laden watery debris flows are thought to have transferred limestone debris from the upper to middle hillslope, where siliciclastic sand matrix was incorporated and solifluctional creep prevailed, accompanied by slope sheetwash processes. Carbonate cementation of the talus occurred in phreatic conditions during the penultimate Odranian/Warthanian interglacial (marine isotope stage 7), when soils formed and local springs supplied carbonate-saturated groundwater. The patchy preservation of cemented colluvium indicates its erosional relics. The Pleistocene colluvial mantle in the Kraków Highland was probably extensive, but was removed by subsequent erosion where non-cemented.

Gradzi?ski, Micha?; Hercman, Helena; Staniszewski, Krzysztof

2014-06-01

86

Performance of Lime-Soda Sinter Process Residue in the Manufacture of Sulfate-Resistant Portland Cement.  

National Technical Information Service (NTIS)

The residue from the Ames Lime-Soda Sinter Process for recovering alumina from power plant fly ash consists largely of dicalcium silicate and shows promise as a raw material for the manufacture of a low-alumina, sulfate-resistant portland cement. A labora...

G. Burnet J. A. Chesley

1986-01-01

87

Low Temperature Processing of Boron Carbide Cement Composite for Tough, Wear Resistant Structures.  

National Technical Information Service (NTIS)

This SBIR project has developed a low temperature polymer ceramic composite consisting of boron carbide layers bonded by cement, laminated with polymer sheets. The porosity of the ceramic was minimized by in situ hydrolysis of cement. The material has a l...

K. J. Law E. P. Luther

1997-01-01

88

EVALUATION OF PRIMARY AIR VITIATION FOR NITRIC OXIDE REDUCTION IN A ROTARY CEMENT KILN. VOLUME 3. DATA SUPPLEMENT B  

EPA Science Inventory

The report gives results of tests to evaluate combustion modifications for nitric oxide (NO) reduction and cement product quality in a pilot-scale long-dry-process cement kiln firing pulverized coal. The kiln is rated at 11.35 kg/s (1080 tons/day) of cement with a thermal input r...

89

EVALUATION OF PRIMARY AIR VITIATION FOR NITRIC OXIDE REDUCTION IN A ROTARY CEMENT KILN. VOLUME 2. DATA SUPPLEMENT A  

EPA Science Inventory

The report gives results of tests to evaluate combustion modifications for nitric oxide (NO) reduction and cement product quality in a pilot-scale long-dry-process cement kiln firing pulverized coal. The kiln is rated at 11.35 kg/s (1080 tons/day) of cement with a thermal input r...

90

EVALUATION OF PRIMARY AIR VITIATION FOR NITRIC OXIDE REDUCTION IN A ROTARY CEMENT KILN. VOLUME 1. TECHNICAL REPORT  

EPA Science Inventory

The report gives results of tests to evaluate combustion modifications for nitric oxide (NO) reduction and cement product quality in a pilot-scale long-dry-process cement kiln firing pulverized coal. The kiln is rated at 11.35 kg/s (1080 tons/day) of cement with a thermal input r...

91

Reuse of grits waste for the production of soil--cement bricks.  

PubMed

This investigation focuses on the reuse of grits waste as a raw material for replacing Portland cement by up to 30 wt.% in soil-cement bricks. The grits waste was obtained from a cellulose factory located in south-eastern Brazil. We initially characterized the waste sample with respect to its chemical composition, X-ray diffraction, fineness index, morphology, pozzolanic activity, and pollution potential. Soil-cement bricks were then prepared using the waste material and were tested to determine their technological properties (e.g., water absorption, apparent density, volumetric shrinkage, and compressive strength). Microstructural evolution was accompanied by confocal microscopy. It was found that the grits waste is mainly composed of calcite (CaCO3) particles. Our results indicate that grits waste can be used economically, safely, and sustainably at weight percentages of up to 20% to partially replace Portland cement in soil-cement bricks. PMID:24140481

Siqueira, F B; Holanda, J N F

2013-12-15

92

Silicon production process evaluations  

NASA Technical Reports Server (NTRS)

The chemical engineering analysis of the preliminary process design of a process for producing solar cell grade silicon from dichlorosilane is presented. A plant to produce 1,000 MT/yr of silicon is analyzed. Progress and status for the plant design are reported for the primary activities of base case conditions (60 percent), reaction chemistry (50 percent), process flow diagram (35 percent), energy balance (10 percent), property data (10 percent) and equipment design (5 percent).

1981-01-01

93

Properties of cement waste composites  

SciTech Connect

Many nominally inert waste materials can be activated by alkaline substances, including Ca(OH){sub 2} and Portland cement, to form valuable supplementary cementitious materials. Waste materials are inherently more variable in composition than well specified, manufactured materials. Nevertheless, sufficient characterization techniques are available to permit the specification of materials such as fly ash and blast furnace slags with confidence. Applications for other processed waste materials, e.g. metakaolin, are being developed. Properly applied, these wastes can actually improve the performance of cement materials. The leach testing of products containing potentially hazardous waste materials, suited only for disposal, is described.

Glasser, F.P. [Univ. of Aberdeen (United Kingdom). Dept. of Chemistry] [Univ. of Aberdeen (United Kingdom). Dept. of Chemistry

1996-12-31

94

Silicon production process evaluations  

NASA Technical Reports Server (NTRS)

Chemical engineering analysis of the HSC process (Hemlock Semiconductor Corporation) for producing silicon from dichlorosilane in a 1,000 MT/yr plant was continued. Progress and status for the chemical engineering analysis of the HSC process are reported for the primary process design engineering activities: base case conditions (85%), reaction chemistry (85%), process flow diagram (60%), material balance (60%), energy balance (30%), property data (30%), equipment design (20%) and major equipment list (10%). Engineering design of the initial distillation column (D-01, stripper column) in the process was initiated. The function of the distillation column is to remove volatile gases (such as hydrogen and nitrogen) which are dissolved in liquid chlorosilanes. Initial specifications and results for the distillation column design are reported including the variation of tray requirements (equilibrium stages) with reflux ratio for the distillation.

1981-01-01

95

Utilization of municipal solid waste incineration fly ash for sulfoaluminate cement clinker production.  

PubMed

The feasibility of partially substituting raw materials with municipal solid waste incineration (MSWI) fly ash in sulfoaluminate cement (SAC) clinker production was investigated by X-ray diffraction (XRD), compressive strength and free expansion ratio testing. Three different leaching tests were used to assess the environmental impact of the produced material. Experimental results show that the replacement of MSWI fly ash could be taken up to 30% in the raw mixes. The good quality SAC clinkers are obtained by controlling the compositional parameters at alkalinity modulus (C(m)) around 1.05, alumina-sulfur ratio (P) around 2.5, alumina-silica ratio (N) around 2.0~3.0 and firing the raw mixes at 1250 °C for 2h. The compressive strengths of SAC are high in early age while that develop slowly in later age. Results also show that the expansive properties of SAC are strongly depended on the gypsum content. Leaching studies of toxic elements in the hydrated SAC-based system reveal that all the investigated elements are well bounded in the clinker minerals or immobilized by the hydration products. Although some limited positive results indicate that the SAC prepared from MSWI fly ash would present no immediate thread to the environment, the long-term toxicity leaching behavior needs to be further studied. PMID:21616653

Wu, Kai; Shi, Huisheng; Guo, Xiaolu

2011-01-01

96

The Product Development Process.  

ERIC Educational Resources Information Center

Product development has emerged very recently as an area of specialization within the field of education, having received its greatest impetus with the establishment of the federally funded educational research and development centers in 1964 and the regional educational laboratories in 1965. The first part of this three-part document defines…

Bowman, Harry L.

97

Silicon production process evaluations  

NASA Technical Reports Server (NTRS)

Chemical engineering analysis was continued for the HSC process (Hemlock Semiconductor Corporation) in which solar cell silicon is produced in a 1,000 MT/yr plant. Progress and status are reported for the primary engineering activities involved in the preliminary process engineering design of the plant base case conditions (96%), reaction chemistry (96%), process flow diagram (85%), material balance (85%), energy balance (60%), property data (60%), equipment design (40%), major equipment list (30%) and labor requirements (10%). Engineering design of the second distillation column (D-02, TCS column) in the process was completed. The design is based on a 97% recovery of the light key (TCS, trichlorosilane) in the distillate and a 97% recovery of the heavy key (TET, silicon tetrachloride) in the bottoms. At a reflux ratio of 2, the specified recovery of TCS and TET is achieved with 20 trays (equilibrium stages, N=20). Respective feed tray locations are 9, 12 and 15 (NF sub 1 = 9, NF sub 2 = 12,, and NF sub 3 = 15). A total condenser is used for the distillation which is conducted at a pressure of 90 psia.

1982-01-01

98

Lunar cement  

NASA Technical Reports Server (NTRS)

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.

Agosto, William N.

1992-01-01

99

Lunar cement  

NASA Astrophysics Data System (ADS)

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.

Agosto, William N.

100

Recovery Act Production of Algal BioCrude Oil from Cement Plant Carbon Dioxide. Final Report.  

National Technical Information Service (NTIS)

The consortium, led by Sunrise Ridge Algae Inc, completed financial, legal, siting, engineering and environmental permitting preparations for a proposed demonstration project that would capture stack gas from an operating cement plant and convert the carb...

N. Whitton R. Weber

2010-01-01

101

Evaluation of Life-Cycle Assessment Studies of Chinese Cement Production: Challenges and Opportunities  

SciTech Connect

The use of life-cycle assessment (LCA) to understand the embodied energy, environmental impacts, and potential energy-savings of manufactured products has become more widespread among researchers in recent years. This paper reviews recent LCA studies in the cement industry in China and in other countries and provides an assessment of the methodology used by the researchers compared to ISO LCA standards (ISO 14040:2006, ISO 14044:2006, and ISO/TR 14048:2002). We evaluate whether the authors provide information on the intended application, targeted audience, functional unit, system boundary, data sources, data quality assessment, data disaggregation and other elements, and draw conclusions regarding the level of adherence to ISO standards for the papers reviewed. We found that China researchers have gained much experience during last decade, but still have room for improvement in establishing boundaries, assessing data quality, identifying data sources, and explaining limitations. The paper concludes with a discussion of directions for future LCA research in China.

Lu, Hongyou; Masanet, Eric; Price, Lynn

2009-05-29

102

A thermodynamic model for blended cements. II: Cement hydrate phases; thermodynamic values and modelling studies  

NASA Astrophysics Data System (ADS)

Blended Portland cements are likely to form a substantial proportion of repository materials for the disposal of radioactive waste in the UK. A thermodynamic model has been developed therefore in order to predict the composition of the solid and aqueous phases in blended cements as a function of the bulk cement composition. The model is based on simplifying cement to the system CaO sbnd SiO 2sbnd Al 2O 3sbnd SO 4sbnd MgO sbnd H 2O, which constitutes 95% of most cement formulations. Solubility data for hydrogarnet and ettringite suggest that they dissolve congruently and that conventional solubility products can be used to model their dissolution. A solubility model for the siliceous hydrogarnet series, based on ideal solid solution on either side of an immiscibility gap, closely matches experimental solubility data. Solubility data for hydrotalcite and gehlenite hydrate are less consistent and indicative of more complex dissolution processes. On the basis of earlier work, an accurate solubility model is described for hydrated calcium silicate gels in the CaO sbnd SiO 2sbnd H 2O system. Together, these solubility models form a relatively complete thermodynamic model for blended cements. Model predictions for fully matured cement blends are compared to the compositions of pore fluids extracted from aged cement blends. Departures from expected behaviour occur in alkali-bearing systems and are discussed.

Bennett, D. G.; Read, D.; Atkins, M.; Glasser, F. P.

1992-08-01

103

The use of electrical impedance spectroscopy for monitoring the hydration products of Portland cement mortars with high percentage of pozzolans  

SciTech Connect

In this paper, mortars and pastes containing large replacement of pozzolan were studied by mechanical strength, thermogravimetric analysis (TGA), scanning electronic microscopy (SEM), mercury intrusion porosimetry (MIP) and electrical impedance spectroscopy (EIS). The effect of metakaolin (35%) and fly ash (60%) was evaluated and compared with an inert mineral addition (andalusite). The portlandite content was measured, finding that the pozzolanic reaction produced cementing systems with all portlandite fixed. The EIS measurements were analyzed by the equivalent electrical circuit (EEC) method. An EEC with three branches in parallel was applied. The dc resistance was related to the degree of hydration and allowed us to characterize plain and blended mortars. A constant phase element (CPE) quantified the electrical properties of the hydration products located in the solid–solution interface and was useful to distinguish the role of inert and pozzolanic admixtures present in the cement matrix.

Cruz, J.M. [Departamento de Física Aplicada, Universitat Politècnica de València, Camino de Vera, 46022, Valencia (Spain)] [Departamento de Física Aplicada, Universitat Politècnica de València, Camino de Vera, 46022, Valencia (Spain); Fita, I.C., E-mail: infifer@fis.upv.es [Departamento de Física Aplicada, Universitat Politècnica de València, Camino de Vera, 46022, Valencia (Spain); Soriano, L.; Payá, J.; Borrachero, M.V. [ICITECH, Instituto de Ciencia y Tecnología del Hormigón, Universitat Politècnica de València (Spain)] [ICITECH, Instituto de Ciencia y Tecnología del Hormigón, Universitat Politècnica de València (Spain)

2013-08-15

104

Products and Processes: Synergistic Relationships  

ERIC Educational Resources Information Center

Most people agree that products are the culmination of what students have studied. For this article, "product" will refer to students' abilities to create outcomes and design artifacts. Those abilities are guided by four processes: inquiry-based learning, use of a research model, use of Web 2.0 tools, and appropriate assessments.…

Wallace, Virginia; Husid, Whitney

2013-01-01

105

Plasma Spray and Pack Cementation Process Optimization and Oxidation Behaviour of Novel Multilayered Coatings  

NASA Astrophysics Data System (ADS)

The hot section components in gas turbines are subjected to a harsh environment with the temperature being increased continuously. The higher temperature has directly resulted in severe oxidation of these components. Monolithic coatings such as MCrAIY and aluminide have been traditionally used to protect the components from oxidation; however, increased operating temperature quickly deteriorates the coatings due to accelerated diffusion of aluminum in the coatings. To improve the oxidation resistance a group of multilayered coatings are developed in this study. The multilayered coatings consist of a Cr-Si co-deposited layer as the diffusion barrier, a plasma sprayed NiCrA1Y coating as the middle layer and an aluminized top layer. The Cr-Si and aluminized layers are fabricated using pack cementation processes and the NiCrA1Y coatings are produced using the Mettech Axial III(TM) System. All of the coating processes are optimized using the methodology of Design of Experiments (DOE) and the results are analyzed using statistical method. The optimal processes are adopted to fabricate the multilayered coatings for oxidation tests. The coatings are exposed in air at 1050°C and 1150°C for 1000 hr. The results indicate that a Cr layer and a silicon-rich barrier layer have formed on the interface between the Cr-Si coating and the NiCrA1Y coating. This barrier layer not only prevents aluminum and chromium from diffusing into the substrate, but also impedes the diffusion of other elements from the substrate into the coating. The results also reveal that, for optimal oxidation resistance at 1050°C, the top layer in a multilayered coating should have at least Al/Ni ratio of one; whereas the multilayered coating with the All Ni ratio of two in the top layer exhibits the best oxidation resistance at 1150°C. The DOE methodology provides an excellent means for process optimization and the selection of oxidation test matrix, and also offers a more thorough understanding of the effects of process parameters on the coating microstructure, and the effects of layers and their interactions on the oxidation behavior of the multilayered coatings.

Gao, Feng

106

Reducing cement's CO2 footprint  

USGS Publications Warehouse

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.

van Oss, Hendrik G.

2011-01-01

107

High temperature lightweight foamed cements  

DOEpatents

Cement slurries are disclosed which are suitable for use in geothermal wells since they can withstand high temperatures and high pressures. The formulation consists of cement, silica flour, water, a retarder, a foaming agent, a foam stabilizer, and a reinforcing agent. A process for producing these cements is also disclosed.

Sugama, Toshifumi (Mastic Beach, NY)

1989-01-01

108

High temperature lightweight foamed cements  

DOEpatents

Cement slurries are disclosed which are suitable for use in geothermal wells since they can withstand high temperatures and high pressures. The formulation consists of cement, silica flour, water, a retarder, a foaming agent, a foam stabilizer, and a reinforcing agent. A process for producing these cements is also disclosed. 3 figs.

Sugama, Toshifumi.

1989-10-03

109

Leaching of hazardous substances from a composite construction product - an experimental and modelling approach for fibre-cement sheets.  

PubMed

The leaching behaviour of a commercial fibre-cement sheet (FCS) product has been investigated. A static pH dependency test and a dynamic surface leaching test have been performed at lab scale. These tests allowed the development of a chemical-transport model capable to predict the release of major and trace elements over the entire pH range, in function of time. FCS exhibits a cement-type leaching behaviour with respect to the mineral species. Potentially hazardous species are released in significant quantities when compared to their total content. These are mainly heavy metals commonly encountered in cement matrixes and boron (probably added as biocide). Organic compounds considered as global dissolved carbon are released in significant concentrations, originating probably from the partial degradation of the organic fibres. The pesticide terbutryn (probably added during the preservative treatment of the organic fibres) was systematically identified in the leachates. The simulation of an upscaled runoff scenario allowed the evaluation of the cumulative release over long periods and the distribution of the released quantities in time, in function of the local exposure conditions. After 10 years of exposure the release reaches significant fractions of the species' total content - going from 4% for Cu to near 100% for B. PMID:24295776

Lupsea, Maria; Tiruta-Barna, Ligia; Schiopu, Nicoleta

2014-01-15

110

Constrained self-tuning control of raw material blending process in cement industry  

Microsoft Academic Search

The main goal of raw meal blending control in cement industry is to maintain near the reference moduli values and to decrease the variation of the chemical composition, rejecting disturbances. For this purpose, some commercial control systems are available today. However, the control structure in these systems usually consists of quality control. In this paper, the proposed constrained self-tuning controller

Can Ozsoy; Cuneyt Yilmaz; Mehmet Cetinkaya; Emin TaSkazan

1997-01-01

111

Recovery Act Production of Algal BioCrude Oil from Cement Plant Carbon Dioxide  

SciTech Connect

The consortium, led by Sunrise Ridge Algae Inc, completed financial, legal, siting, engineering and environmental permitting preparations for a proposed demonstration project that would capture stack gas from an operating cement plant and convert the carbon dioxide to beneficial use as a liquid crude petroleum substitute and a coal substitute, using algae grown in a closed system, then harvested and converted using catalyzed pyrolysis.

Robert Weber; Norman Whitton

2010-09-30

112

Asphalt cement  

MedlinePLUS

... petroleum material that hardens when it cools. Asphalt cement poisoning occurs when someone swallows asphalt. This is ... Road paving materials Roofing materials Tile cements Note: This list may not include all uses of asphalt.

113

Designing of Cement-Based Formula for Solidification\\/Stabilization of Hazardous, Radioactive, and Mixed Wastes  

Microsoft Academic Search

Solidification\\/stabilization (S\\/S) is often used to treat waste or to remediate contaminated sites. Many people feel S\\/S is just a process to consolidate waste into a solid product for disposal using cementing materials. This article describes designing a cement-based formula for solidification\\/stabilization of wastes or contaminated soils from aspects of both the cement chemistry and the environmental chemistry. The discussion

CAIJUN SHI; ROGER SPENCE

2004-01-01

114

Discovery Reconceived: Product before Process  

ERIC Educational Resources Information Center

Motivated by the question, "What exactly about a mathematical concept should students discover, when they study it via discovery learning?", I present and demonstrate an interpretation of discovery pedagogy that attempts to address its criticism. My approach hinges on decoupling the solution process from its resultant product. Whereas theories of…

Abrahamson, Dor

2012-01-01

115

Cement-based electronics  

NASA Astrophysics Data System (ADS)

The term Intelligent Highway is usually intended to mean external systems that are added to pre-existing highways. However, the ability to construct basic passive electronic elements is demonstrated employing electrically dissimilar Portland cement pastes. These electronic elements include resistors, rectifying pn-junctions, piezoelectric and piezoresistive sensors, and thermocouple junctions. It may therefore be possible to build intelligence into the highway itself utilizing cement-based electronic devices. As compared to semiconductor-based electronic components, those derived from cement have minimal materials and processing costs, do not require clean rooms, and are mechanically more rugged. Results and characterizations are presented for resistive elements and rectifying pn-junctions derived from admixtures of stainless steel fiber (n-type) and carbon fiber (p-type) in Portland cement. These elements are then combined to produce a monolithic cement-based digital logic 2-input AND gate.

Konesky, Gregory A.

116

Change in pore structure and composition of hardened cement paste during the process of dissolution  

SciTech Connect

An understanding about the dissolution phenomena of cement hydrates is important to assess changes in the long-term performance of radioactive waste disposal facilities. To investigate the alteration associated with dissolution, dissolution tests of ordinary Portland cement (OPC) hydrates were performed. Through observation of the samples after leaching, it was confirmed that ettringite precipitation increased as the dissolution of the portlandite and the C-S-H gel progressed. EPMA performed on cross-sections of the solid phase showed a clear difference between the altered and unaltered parts. The boundary between the two parts was termed the portlandite (CH) dissolution front. As the leaching period became longer, the CH dissolution front shifted toward the inner part of the sample. A linear relationship was derived by plotting the distance moved by the CH dissolution front against the square root of the leaching time. This indicated Ca ion movement by diffusion.

Haga, Kazuko; Shibata, Masahito; Hironaga, Michihiko; Tanaka, Satoru; Nagasaki, Shinya

2005-05-01

117

Traditional soyfoods: processing and products.  

PubMed

Although soyfoods have been consumed for more than 1000 years, only for the past 15 years have they made an inroad into Western cultures and diets. Soyfoods are typically divided into two categories: nonfermented and fermented. Traditional nonfermented soyfoods include fresh green soybeans, whole dry soybeans, soy nuts, soy sprouts, whole-fat soy flour, soymilk and soymilk products, tofu, okara and yuba. Traditional fermented soyfoods include tempeh, miso, soy sauces, natto and fermented tofu and soymilk products. This paper presents a brief overview of processing techniques used in the manufacture of traditional soyfoods. PMID:7884535

Golbitz, P

1995-03-01

118

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

SciTech Connect

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.

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

2010-12-22

119

Process Flow Chart for Immobilizing of Radioactive High Concentration Sodium Hydroxide Product from the Sodium Processing Facility at the BN-350 Nuclear power plant in Aktau, Kazakhstan  

SciTech Connect

This paper describes the results of a joint research investigations carried out by the group of Kazakhstan, British and American specialists in development of a new material for immobilization of radioactive 35% sodium hydroxide solutions from the sodium coolant processing facility of the BN-350 nuclear power plant. The resulting solid matrix product, termed geo-cement stone, is capable of isolating long lived radionuclides from the environment. The physico-mechanical properties of geo-cement stone have been investigated and the flow chart for its production verified in a full scale experiments. (author)

Burkitbayev, M.; Omarova, K.; Tolebayev, T. [Ai-Farabi Kazakh National University, Chemical Faculty, Republic of Kazakhstan (Kazakhstan); Galkin, A. [KATEP Ltd., Republic of Kazakhstan (Kazakhstan); Bachilova, N. [NIISTROMPROEKT Ltd., Republic of Kazakhstan (Kazakhstan); Blynskiy, A. [Nuclear Technology Safety Centre, Republic of Kazakhstan (Kazakhstan); Maev, V. [MAEK-Kazatomprom Ltd., Republic of Kazakhstan (Kazakhstan); Wells, D. [NUKEM Limited- a member of the Freyssinet Group, Winfrith Technology Centre, Dorchester, Dorset (United Kingdom); Herrick, A. [NUKEM Limited- a member of the Freyssinet Group, Caithness (United Kingdom); Michelbacher, J. [Idaho National Laboratory, Idaho Falls (United States)

2008-07-01

120

Energy Efficiency Improvement Opportunities for the Cement Industry  

SciTech Connect

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 this report is based on publicly-available reports, journal articles, and case studies from applications of technologies around the world.

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

2008-01-31

121

Use of secondary mineralizing raw materials in cement production. A case study of a wolframite–stibnite ore  

Microsoft Academic Search

It has been found that certain foreign elements, despite their low concentration in cement raw mix, improve the reactivity of the cement raw mix. The aim of this research is to investigate the possibility of introducing small amounts of minerals, containing these elements, into the cement raw mix. A stibnite–wolframite mineral was selected in order to introduce W, Sb and

G. Kakali; S. Tsivilis; K. Kolovos; N. Voglis; J. Aivaliotis; T. Perraki; E. Passialakou; M. Stamatakis

2005-01-01

122

Interfacial analysis between zirconia-containing glass and cement by X-ray photoelectron spectroscopy  

Microsoft Academic Search

Though glass fibre reinforced cement (GRC) composites have become widely used, their mechanical properties such as strength and ductility gradually deteriorate [1]. This has been explained by the reduction of fibre tensile strength by alkali corrosion in the cement and the penetration of hydrating products into fibre bundles causing physical property changes [1-3]. These two processes occur simultaneously but their

Naoto Koshizaki

1988-01-01

123

Properties and hydration of blended cements with steelmaking slag  

Microsoft Academic Search

The present research study investigates the properties and hydration of blended cements with steelmaking slag, a by-product of the conversion process of iron to steel. For this purpose, a reference sample and three cements containing up to 45% w\\/w steel slag were tested. The steel slag fraction used was the “0–5 mm”, due to its high content in calcium silicate phases.

S. Kourounis; S.. Tsivilis; P. E. Tsakiridis; G. D. Papadimitriou; Z. Tsibouki

2007-01-01

124

Modifications of sulfur polymer cement (SPC) stabilization and solidification (S/S) process  

SciTech Connect

This paper addresses the effectiveness of using sulfur polymer cement (SPC) as a binder to stabilize/solidify lead-contaminated soils. SPC, which has been used as a construction material because of its excellent resistance to acid and salt environments and its superior water tightness as compared with Portland cement concrete, has recently emerged as a possible alternative binder to stabilize/solidify soils contaminated with hazardous, low-level radioactive and mixed wastes. However, it was found that the use of SPC alone could not satisfactorily stabilize/solidify lead-contaminated soils. Nevertheless, it was shown that additives, such as sodium sulfide or sodium sulfite, could be used to greatly enhance the ability of SPC to react chemically with lead contaminants, and physicochemically to bind these compounds. These enable us significantly to lower the leachability (e.g. from 77.8 mg Pb/l to 1.28 mg Pb/l in EPA TCLP extract) of the SPC-treated wastes to the point where they can be recycled as some form of construction material.

Lin, S.L.; Lai, J.S.; Chian, E.S.K. [Georgia Inst. of Tech., Atlanta, GA (United States). School of Civil and Environmental Engineering] [Georgia Inst. of Tech., Atlanta, GA (United States). School of Civil and Environmental Engineering

1995-12-31

125

Immediate bonding effectiveness of contemporary composite cements to dentin.  

PubMed

The objective of this study was to compare the one-week bonding effectiveness of nine contemporary composite cements used to lute ceramic to dentin and to determine an appropriate processing method for pretesting failures. The microtensile bond strengths (µTBS) of different luting agents including five self-adhesive cements (Unicem, 3 M ESPE; Maxcem, Kerr; Monocem, Shofu; G-Cem, GC; and Multilink Sprint, Ivoclar-Vivadent), two self-etch cements (Panavia F2.0 and Clearfil Esthetic Cement, Kuraray), and two etch-and-rinse cements (Calibra, Dentsply, and Variolink II, Ivoclar-Vivadent) were measured using a standardized protocol. As control, a two-step self-etch adhesive combined with a restorative composite (Clearfil SE+Clearfil APX, Kuraray) were included as luting material. Depending on the processing of the pretesting failures, two groups of cements could be distinguished: (1) those with low bond strength and many pretesting failures and (2) those with relatively high bond strength and few pretesting failures. Nevertheless, the control luting procedure involving a self-etch adhesive combined with a restorative composite presented with a significantly higher µTBS. The µTBS was clearly product-dependent rather than being dependent on the actual adhesive approach. Fracture analysis indicated that failure usually occurred at the dentin-cement interface especially for the cements with low bond strength and many pretesting failures. Depending on the cement system, an adequate immediate ceramic-to-dentin bond strength can be obtained, even with self-adhesive cements that do not use a separate dental adhesive. Yet, the self-etch adhesive Clearfil SE combined with the restorative composite revealed a superior bonding performance and should therefore be preferred in clinical situations where the restoration transmits light sufficiently. PMID:19705169

Sarr, Mouhamed; Mine, Atsushi; De Munck, Jan; Cardoso, Marcio Vivan; Kane, Abdoul Wakhabe; Vreven, José; Van Meerbeek, Bart; Van Landuyt, Kirsten L

2010-10-01

126

A modified technique for extraoral cementation of implant retained restorations for preventing excess cement around the margins  

PubMed Central

The major drawback of cement-retained restorations is the extrusion of the excess cement into the peri-implant sulcus, with subsequent complications. Insufficient removal of the excess cement may initiate a local inflammatory process, which may lead to implant failure. This article presents a method of controlling cement flow on implant abutments, minimizing the excess cement around implant-retained restorations.

2014-01-01

127

Cement disease.  

PubMed

Does "cement disease" exist? The bony environment surrounding a loosened cemented prosthesis is an abnormal pathologic condition which, if left unattended, will progress to a total failure of the joint including an inhibition of function and immobilizing pain. That biomaterial properties of the cement used for fixation also contribute to the pathologic state separates this disease from other modes of loosening. This leads inevitably to the conclusion that "cement disease" does exist. Methyl methacrylate has revolutionized the treatment of severe joint dysfunction. There can be no doubt that improving surgical technique, cement handling, and the cement itself will continue to improve the results and reduce the incidence of failure due to loosening. Cement is undoubtedly satisfactory for elderly patients with low activity levels and relatively short life expectancies. However, because of the inherent biologic and biomechanical properties of methyl methacrylate, it is unlikely that it can be rendered satisfactory in the long run for the young, the active, or the overweight patient, for whom alternatives are currently being sought. In such cases, the elimination of "cement disease" can only occur with the elimination of cement. Alternatives include the search for other grouting materials and the development of prostheses with satisfactory surfaces for either press-fit or biologic ingrowth. PMID:3315375

Jones, L C; Hungerford, D S

1987-12-01

128

Curricular Mapping: Process and Product  

PubMed Central

Curricular maps can be used to link ability-based outcomes (ABOs) and content to courses in PharmD curricula as one component of an overall assessment plan. Curricular maps can also be used to meet some of the requirements delineated by Accreditation Council for Pharmacy Education, Standards 2007. Five steps can be followed to help ensure the successful production of a curricular map that both meets accreditation requirements and helps to inform curricular improvements. A case study is presented detailing how one college implemented a curricular mapping process that was subsequently used as data to inform curricular revisions.

McAuley, James W.; Wallace, Lane J.; Frank, Sylvan G.

2008-01-01

129

Characterization of eco-cement paste produced from waste sludges.  

PubMed

In this study, marble sludge, sewage sludge, drinking water treatment plant sludge, and basic oxygen furnace sludge were used as replacements for limestone, sand, clay, and iron slag, respectively, as the raw materials for the production of cement in order to produce eco-cement. It was found that it is feasible to use marble sludge to replace up to 50% of the limestone and also that other materials can serve as total replacements for the raw materials typically used in the production of cement. The major components of Portland cement were all found in eco-cement clinkers. The eco-cement was confirmed to produce calcium hydroxide and calcium silicate hydrates during the hydration process, increasing densification with the curing age. The compressive strength (S(c)) and microstructural evaluations conducted at 28 d revealed the usefulness of eco-cement. It was observed that the S(c) data correlated linearly with the pore volume (P) data at 28 d. The proposed model equation could be represented as S(c)=178-461P (correlation coefficient, R(2)=0.96). Two parameters, the large capillary pore volume and the medium capillary pore volume, were evaluated using multiple regression analysis. PMID:21570706

Yen, Chi-Liang; Tseng, Dyi-Hwa; Lin, Tung-Tsan

2011-06-01

130

The FGM Concept in the Development of Fiber Cement Components  

NASA Astrophysics Data System (ADS)

The FGM concept appears promising in improving the mechanical performance and reducing production costs of fiber cement building components. However, it has not yet been broadly applied to fiber cement technology. In this study we analyze the functionally graded fiber cement concept and its potential for industrial application in Hatschek machines. The conventional Hatschek process is summarized as well as the proposed modifications to allow FGM fiber cement production. The feasibility of producing functionally graded fiber cement by grading PVA fiber content was experimentally evaluated. Thermogravimetric (TG) and Scanning Electron Microscope (SEM) analysis were used to evaluate fiber distribution profiles. Four-point bending tests were applied to evaluate the mechanical performance of both conventional and functionally graded composites. The results shows that grading PVA fiber content is an effective way to produce functionally graded fiber cement, allowing the reduction of the total fiber volume without significant reduction on composite MOR. TG tests were found adequate to assess fiber content at different positions in functionally graded fiber cements.

Dias, C. M. R.; Savastano, H.; John, V. M.

2008-02-01

131

Cement evaluation tool: a new approach to cement evaluation  

SciTech Connect

Cement bond logging achieves its greatest utility when it provides the production engineer with precise indications of cement strength and distribution around the casing. Zone isolation is of critical importance in production. Previous logging systems have yielded measures of cement bond that were circumferential averages of cement quality. These were difficult to interpret. Additionally, they were sensitive to the degree of shear coupling between pipe, cement, and formation and thus were affected by microannulus. The cement evaluation tool (CET) described here overcomes these difficulties. It provides a measurement of cement presence and strength, which is largely insensitive to microannulus. Its log output is interpreted easily. Tool design allows examination of the casing circumferentially at each depth. Impedance behind casing is measured. Laboratory calibration measurements allow this to be presented in terms of cement compressive strength. Cement channels are distinguished easily, and a zone isolation indicator can be presented. Additionally, casing internal diameter and distortion are displayed. European and North American field tests have been completed, and performance for a variety of well conditions is discussed. The ability of the tool to identify channels is confirmed. Sequential runs with and without excess pressure demonstrate immunity to microannulus in cases where CBL is affected but where microannulus is small enough to prohibit hydraulic communication. Geometrical measurements have been good indicators of casing deformation and have identified casing corrosion and wear.

Froelich, B.; Dumont, A.; Pittman, D.; Seeman, B.

1982-08-01

132

Simultaneous chromizing-aluminizing coating of low alloy steels by a halide-activated pack cementation process  

SciTech Connect

The simultaneous chromizing-aluminizing of low-alloy steels has achieved Kanthal-like surface compositions of 16--2lCr and 5--8 wt%Al by the use of cementation packs with a Cr-Al masteralloy and an NH[sub 4]Cl activator salt. An initial preferential deposition of Al into the alloy induces the phase transformation from austenite to ferrite at the 1150[degrees]C process temperature. The low solubility of carbon in ferrite results in the rejection of solute C into the core of the austenitic substrate, thereby preventing the formation of an external Cr-carbide layer, which would otherwise block aluminizing and chromizing. The deposition and rapid diffusion of Cr and Al into the external bcc ferrite layer follows. Parabolic cyclic oxidation kinetics for alumina growth in air were observed over a wide range of relatively low temperatures (637--923[degrees]C).

Geib, F.D.; Rapp, R.A. (Ohio State Univ., Columbus, OH (United States). Dept. of Materials Science and Engineering)

1992-11-01

133

Simultaneous chromizing-aluminizing coating of low alloy steels by a halide-activated pack cementation process  

SciTech Connect

The simultaneous chromizing-aluminizing of low-alloy steels has achieved Kanthal-like surface compositions of 16--2lCr and 5--8 wt%Al by the use of cementation packs with a Cr-Al masteralloy and an NH{sub 4}Cl activator salt. An initial preferential deposition of Al into the alloy induces the phase transformation from austenite to ferrite at the 1150{degrees}C process temperature. The low solubility of carbon in ferrite results in the rejection of solute C into the core of the austenitic substrate, thereby preventing the formation of an external Cr-carbide layer, which would otherwise block aluminizing and chromizing. The deposition and rapid diffusion of Cr and Al into the external bcc ferrite layer follows. Parabolic cyclic oxidation kinetics for alumina growth in air were observed over a wide range of relatively low temperatures (637--923{degrees}C).

Geib, F.D.; Rapp, R.A. [Ohio State Univ., Columbus, OH (United States). Dept. of Materials Science and Engineering

1992-11-01

134

Thermal Shock-resistant Cement  

SciTech Connect

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 cement, causing its volume to expand.

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

2012-02-01

135

Blended cement using volcanic ash and pumice  

Microsoft Academic Search

This paper reports the results of investigation to assess the suitability of volcanic ash (VA) and pumice powder (VPP) for blended cement production. Tests were conducted on cement where Portland cement (PC) was replaced by VA and VPP within the range of 0 to 50%. The physical and chemical properties of VA and VPP were critically reviewed to evaluate the

Khandaker M. Anwar Hossain

2003-01-01

136

XML-based product information processing method for product design  

NASA Astrophysics Data System (ADS)

Design knowledge of modern mechatronics product is based on information processing as the center of the knowledge-intensive engineering, thus product design innovation is essentially the knowledge and information processing innovation. Analysis of the role of mechatronics product design knowledge and information management features, a unified model of XML-based product information processing method is proposed. Information processing model of product design includes functional knowledge, structural knowledge and their relationships. For the expression of product function element, product structure element, product mapping relationship between function and structure based on the XML model are proposed. The information processing of a parallel friction roller is given as an example, which demonstrates that this method is obviously helpful for knowledge-based design system and product innovation.

Zhang, Zhen Yu

2011-12-01

137

Cementing apparatus  

SciTech Connect

For use in cementing a casing string within a well bore, an assembly is described comprising: a float collar including an outer body connectable as part of the casing string and an inner body having a bore there through having upper and lower ends and a valve member in the bore to permit flow downwardly and prevent flow upwardly there through, a cement plug including a body having a bore there through and upper and lower ends with a frangible diaphragm there across and lips there about flexibly engagable with the casing string to permit the plug to be prepared downwardly onto the float collar, the upper end of the bore of the float collar having threads thereon and the lower end of the body of the cement plug having threads there about for limited make-up with the threads in the bore of the float collar in response to rotation of the cement plug in one direction, and a wiper plug comprising a body having lips there about flexibly engagable with the casing string to permit the wiper plug to be pumped downwardly onto the cement plug, the upper end of the bore of the cement plug having threads thereon and the lower end of the bore of the body of the wiper plug having threads there about for limited make-up with the threads in the bore of the cement plug in response to rotation of the wiper plug in said one direction, and the inner body of the float collar and the bodies of the cement and wiper plugs being of a drillable material.

Coone, M.G.; Cole, F.

1993-08-10

138

Characterization of Spatial Impact of Particles Emitted from a Cement Material Production Facility on Outdoor Particle Deposition in the Surrounding Community  

PubMed Central

The objective of this study was to estimate the contribution of a facility that processes steel production slag into raw material for cement production to local outdoor particle deposition in Camden, NJ. A dry deposition sampler that can house four 37-mm quartz fiber filters was developed and used for the collection of atmospheric particle deposits. Two rounds of particle collection (3–4 weeks each) were conducted in 8–11 locations 200–800 m downwind of the facility. Background samples were concurrently collected in a remote area located ~2 km upwind from the facility. In addition, duplicate surface wipe samples were collected side-by-side from each of the 13 locations within the same sampling area during the first deposition sampling period. One composite source material sample was also collected from a pile stored in the facility. Both the bulk of the source material and the <38 ?m fraction subsample were analyzed to obtain the elemental source profile. The particle deposition flux in the study area was higher (24–83 mg/m2 day) than at the background sites (13–17 mg/m2·day). The concentration of Ca, a major element in the cement source production material, was found to exponentially decrease with increasing downwind distance from the facility (P < 0.05). The ratio of Ca/Al, an indicator of Ca enrichment due to anthropogenic sources in a given sample, showed a similar trend. These observations suggest a significant contribution of the facility to the local particle deposition. The contribution of the facility to outdoor deposited particle mass was further estimated by three independent models using the measurements obtained from this study. The estimated contributions to particle deposition in the study area were 1.8–7.4% from the regression analysis of the Ca concentration in particle deposition samples against the distance from the facility, 0–11% from the U.S. Environmental Protection Agency (EPA) Chemical Mass Balance (CMB) source-receptor model, and 7.6–13% from the EPA Industrial Source Complex Short Term (ISCST3) dispersion model using the particle-size-adjusted permit-based emissions estimates.

Yu, Chang Ho; Fan, Zhihua (Tina); McCandlish, Elizabeth; Stern, Alan H.; Lioy, Paul J.

2014-01-01

139

Bringing Process to Post Production  

Microsoft Academic Search

Recent developments in the field of business process management have made it possible to effectively deal with large collections of process models that exhibit many similarities but also context-dependent differences. In this paper these developments are exploited in the domain of screen business. In particular, different processes in audio editing are described in an integrated artifact, called reference process model,

Katherine Shortland

140

Passamaquoddy Technology Recovery Scrubber{trademark} at the Dragon Products, Inc. Cement Plant located in Thomaston, Maine. 1990 Annual technical report  

SciTech Connect

The background and process of the Passamaquoddy Technology Recovery Scrubber{trademark} are described. The Scrubber was developed for Dragon Cement Plant in Thomaston, Maine and facilitates a number of process improvements. The exhaust gas is scrubbed of SO{sub 2} with better than 90% efficiency. The kiln dust is cleaned of alkalines and so can be returned to kiln feed instead of dumped to landfill. Potassium sulfate in commercial quantity and purity can be recovered. Distilled water is recovered which also has commercial potential. Thus, various benefits are accrued and no waste streams remain for disposal. The process is applicable to both wet and dry process cement kilns and appears to have potential in any industry which generates acidic gaseous exhausts and/or basic solid or liquid wastes.

Not Available

1990-12-31

141

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

National Technical Information Service (NTIS)

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...

A. Hasanbeigi H. Lu L. Price W. Lan

2009-01-01

142

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

National Technical Information Service (NTIS)

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...

A. Hasanbeigi H. Lu L. Price W. Lan

2009-01-01

143

Utilization of municipal solid waste incineration (MSWI) fly ash in blended cement Part 1: Processing and characterization of MSWI fly ash.  

PubMed

This paper is the first of a series of two articles dealing with the processes applied to MSWI fly ash with a view to reusing it safely in cement-based materials. Part 1 presents two stabilization processes and Part 2 deals with the use of the two treated fly ashes (TFA) in mortars. Two types of binder were used: an Ordinary Portland Cement (OPC) containing more than 95% clinker (CEM I 52.5R) and a binary blend cement composed of 70% ground granulated blast furnace slag and 30% clinker (CEM III-B 42.5N). In this first part, two stabilization processes are presented: the conventional process, called "A", based on the washing, phosphation and calcination of the ash, and a modified process, called "B", intended to eliminate metallic aluminum and sulfate contained in the ash. The physical, chemical and mineralogical characteristics of the two TFA were comparable. The main differences observed were those expected, i.e. TFA-B was free of metallic aluminum and sulfate. The mineralogical characterization of the two TFAs highlighted the presence of large amounts of a calcium aluminosilicate phase taking two forms, a crystalline form (gehlenite) and an amorphous form. Hydration studies on pastes containing mixed TFA and calcium hydroxide showed that this phase reacted with calcium hydroxide to form calcium aluminate hydrates. This formation of hydrates was accompanied by a hardening of the pastes. These results are very encouraging for the reuse of such TFA in cement-based materials because they can be considered as pozzolanic additions and could advantageously replace a part of the cement in cement-based materials. Finally, leaching tests were carried out to evaluate the environmental impact of the two TFAs. The elements which were less efficiently stabilized by process A were zinc, cadmium and antimony but, when the results of the leaching tests were compared with the thresholds of the European landfill directive, TFA-A could nevertheless be accepted at landfills for non-hazardous waste. The modifications of the process led to a significant reduction in the stabilization of chromium, selenium and antimony. PMID:16442718

Aubert, J E; Husson, B; Sarramone, N

2006-08-25

144

Industrially interesting approaches to “low-CO 2” cements  

Microsoft Academic Search

This article discusses the practicality of replacing portland cements with alternative hydraulic cements that could result in lower total CO2 emissions per unit volume of concrete of equivalent performance. Currently, the cement industry is responding rapidly to the perceived societal need for reduced CO2 emissions by increasing the production of blended portland cements using supplementary cementitious materials that are principally

Ellis Gartner

2004-01-01

145

Durability of pulp fiber-cement composites  

NASA Astrophysics Data System (ADS)

Wood pulp fibers are a unique reinforcing material as they are non-hazardous, renewable, and readily available at relatively low cost compared to other commercially available fibers. Today, pulp fiber-cement composites can be found in products such as extruded non-pressure pipes and non-structural building materials, mainly thin-sheet products. Although natural fibers have been used historically to reinforce various building materials, little scientific effort has been devoted to the examination of natural fibers to reinforce engineering materials until recently. The need for this type of fundamental research has been emphasized by widespread awareness of moisture-related failures of some engineered materials; these failures have led to the filing of national- and state-level class action lawsuits against several manufacturers. Thus, if pulp fiber-cement composites are to be used for exterior structural applications, the effects of cyclical wet/dry (rain/heat) exposure on performance must be known. Pulp fiber-cement composites have been tested in flexure to examine the progression of strength and toughness degradation. Based on scanning electron microscopy (SEM), environmental scanning electron microscopy (ESEM), energy dispersive spectroscopy (EDS), a three-part model describing the mechanisms of progressive degradation has been proposed: (1) initial fiber-cement/fiber interlayer debonding, (2) reprecipitation of crystalline and amorphous ettringite within the void space at the former fiber-cement interface, and (3) fiber embrittlement due to reprecipitation of calcium hydroxide filling the spaces within the fiber cell wall structure. Finally, as a means to mitigate kraft pulp fiber-cement composite degradation, the effects of partial portland cement replacement with various supplementary cementitious materials (SCMs) has been investigated for their effect on mitigating kraft pulp fiber-cement composite mechanical property degradation (i.e., strength and toughness losses) during wet/dry cycling. SCMs have been found to be effective in mitigating composite degradation through several processes, including a reduction in the calcium hydroxide content, stabilization of monosulfate by maintaining pore solution pH, and a decrease in ettringite reprecipitation accomplished by increased binding of aluminum in calcium aluminate phases and calcium in the calcium silicate hydrate (C-S-H) phase.

Mohr, Benjamin J.

146

Fabrication Process of Blocks of Radioactive Wastes Encapsulated in Cement and Resistant to Leaching and Salt Solutions.  

National Technical Information Service (NTIS)

Waterproof additives are claimed to decrease water penetration through the cement such as silicone resins, latex emulsions or organic aluminium salts, avoiding leaching of radioactive wastes. (ERA citation 14:021761)

H. Holtz

1987-01-01

147

Estimates of global, regional, and national annual CO emissions from fossil-fuel burning, hydraulic cement production, and gas flaring: 1950--1992  

Microsoft Academic Search

This document describes the compilation, content, and format of the most comprehensive C0-emissions database currently available. The database includes global, regional, and national annual estimates of C0 emissions resulting from fossil-fuel burning, cement manufacturing, and gas flaring in oil fields for 1950--92 as well as the energy production, consumption, and trade data used for these estimates. The methods of Marland

T. A. Boden; G. Marland; R. J. Andres

1995-01-01

148

The effect of grinding process on mechanical properties and alkali–silica reaction resistance of fly ash incorporated cement mortars  

Microsoft Academic Search

The effect of fineness of fly ash on mechanical properties and alkali–silica reaction resistance of cement mortar mixtures incorporating fly ash has been investigated within the scope of this study. Blaine fineness of fly ash has been increased to 907m2\\/kg from its original 290m2\\/kg value by a ball mill. Test samples were prepared by replacing cement 20, 40 and 60%,

Serdar Ayd?n; Çaglayan Karatay; Bülent Baradan

2010-01-01

149

Process Engineering Economics of Bioethanol Production  

Microsoft Academic Search

This work presents a review of studies on the process economics of ethanol production from lignocellulosic\\u000a materials published since 1996. Our objective was to identify the most costly process steps and the impact\\u000a of various parameters on the final production cost, e.g. plant capacity, raw material cost, and overall\\u000a product yield, as well as process configuration. The variation in estimated ethanol

Mats Galbe; Per Sassner; Anders Wingren; Guido Zacchi

150

Synthesis of Portland cement and calcium sulfoaluminate-belite cement for sustainable development and performance  

NASA Astrophysics Data System (ADS)

Portland cement concrete, the most widely used manufactured material in the world, is made primarily from water, mineral aggregates, and portland cement. The production of portland cement is energy intensive, accounting for 2% of primary energy consumption and 5% of industrial energy consumption globally. Moreover, portland cement manufacturing contributes significantly to greenhouse gases and accounts for 5% of the global CO2 emissions resulting from human activity. The primary objective of this research was to explore methods of reducing the environmental impact of cement production while maintaining or improving current performance standards. Two approaches were taken, (1) incorporation of waste materials in portland cement synthesis, and (2) optimization of an alternative environmental friendly binder, calcium sulfoaluminate-belite cement. These approaches can lead to less energy consumption, less emission of CO2, and more reuse of industrial waste materials for cement manufacturing. In the portland cement part of the research, portland cement clinkers conforming to the compositional specifications in ASTM C 150 for Type I cement were successfully synthesized from reagent-grade chemicals with 0% to 40% fly ash and 0% to 60% slag incorporation (with 10% intervals), 72.5% limestone with 27.5% fly ash, and 65% limestone with 35% slag. The synthesized portland cements had similar early-age hydration behavior to commercial portland cement. However, waste materials significantly affected cement phase formation. The C3S--C2S ratio decreased with increasing amounts of waste materials incorporated. These differences could have implications on proportioning of raw materials for cement production when using waste materials. In the calcium sulfoaluminate-belite cement part of the research, three calcium sulfoaluminate-belite cement clinkers with a range of phase compositions were successfully synthesized from reagent-grade chemicals. The synthesized calcium sulfoaluminate-belite cement that contained medium C4A3 S¯ and C2S contents showed good dimensional stability, sulfate resistance, and compressive strength development and was considered the optimum phase composition for calcium sulfoaluminate-belite cement in terms of comparable performance characteristics to portland cement. Furthermore, two calcium sulfoaluminate-belite cement clinkers were successfully synthesized from natural and waste materials such as limestone, bauxite, flue gas desulfurization sludge, Class C fly ash, and fluidized bed ash proportioned to the optimum calcium sulfoaluminate-belite cement synthesized from reagent-grade chemicals. Waste materials composed 30% and 41% of the raw ingredients. The two calcium sulfoaluminate-belite cements synthesized from natural and waste materials showed good dimensional stability, sulfate resistance, and compressive strength development, comparable to commercial portland cement.

Chen, Irvin Allen

151

Modelling of hydrogen production from pore water radiolysis in cemented intermediate level waste  

NASA Astrophysics Data System (ADS)

In France, some of the intermediate and low level wastes are embedded in hydraulic binder and put into concrete canisters. They contain ? and ? emitters which cause an irradiation of water present in the pores of the hydraulic binder. This is responsible for a dihydrogen (H2) production due to radiolysis. EDF R&D and CEA have collaborated since many years in order to understand this phenomenon and develop a model called DO-RE-MI which can predict such a production of dihydrogen in concrete waste packages. A parametric study, using the developed model, was implemented in order to determine the effects of each parameter on H2 production. The main results are presented in this paper.

Foct, F.; Di Giandomenico, M.-V.; Bouniol, P.

2013-07-01

152

Generative inspection process planner for integrated production  

SciTech Connect

This work describes the design prototype development of a generative process planning system for dimensional inspection. The system, IPPEX (Inspection Process Planning EXpert), is a rule-based expert system for integrated production. Using as advanced product modeler, relational databases, and artificial intelligence techniques, IPPEX generates the process plan and part program for the dimensional inspection of products using CMMs. Through an application interface, the IPPEX system software accesses product definition from the product modeler. The modeler is a solid geometric modeler coupled with a dimension and tolerance modeler. Resource data regarding the machines, probes, and fixtures are queried from databases. IPPEX represents inspection process knowledge as production rules and incorporates an embedded inference engine to perform decision making. The IPPEX system, its functional architecture, system architecture, system approach, product modeling environment, inspection features, inspection knowledge, hierarchical planning strategy, user interface formats, and other fundamental issues related to inspection planning and part programming for CMMs are described. 27 refs., 16 figs., 4 tabs.

Brown, C.W. (Allied-Signal Aerospace Co., Kansas City, MO (USA). Kansas City Div.) [Allied-Signal Aerospace Co., Kansas City, MO (USA). Kansas City Div.; Gyorog, D.A. (Kansas Univ., Lawrence, KS (USA). Dept. of Mechanical Engineering) [Kansas Univ., Lawrence, KS (USA). Dept. of Mechanical Engineering

1990-04-01

153

General hydration model for portland cement and blast furnace slag cement  

Microsoft Academic Search

This paper focusses on the evolution of the heat of hydration of hardening concrete or cement based materials. Based on isothermal and adiabatic hydration tests a new general hydration model is developed, valid both for portland cement and blast furnace slag cement. This hydration model enables the calculation of the heat production rate as a function of the actual temperature

L. Taerwe

1995-01-01

154

Cellular automaton simulations of cement hydration and microstructure development  

Microsoft Academic Search

Cellular automaton algorithms, which operate on a starting digital image of a water-cement suspension, are described. The algorithms simulate the microstructure development process due to hydration reactions that occurs between cement and water. This paper describes the evolution of the cement model from a simple model, which treated the cement particles as single-phase materials, with a greatly simplified hydration chemistry,

Dale P. Bentz; Peter V. Coveney; Edward J. Garboczi; Michael F. Kleyn; Paul E. Stutzman

1994-01-01

155

Biotechnology in Food Production and Processing  

NASA Astrophysics Data System (ADS)

The food processing industry is the oldest and largest industry using biotechnological processes. Further development of food products and processes based on biotechnology depends upon the improvement of existing processes, such as fermentation, immobilized biocatalyst technology, and production of additives and processing aids, as well as the development of new opportunities for food biotechnology. Improvements are needed in the characterization, safety, and quality control of food materials, in processing methods, in waste conversion and utilization processes, and in currently used food microorganism and tissue culture systems. Also needed are fundamental studies of the structure-function relationship of food materials and of the cell physiology and biochemistry of raw materials.

Knorr, Dietrich; Sinskey, Anthony J.

1985-09-01

156

Effect of sepiolite on the flocculation of suspensions of fibre-reinforced cement  

SciTech Connect

Sepiolite is used to increase thixotropy of cement slurries for easier processing, to prevent sagging and to provide a better final quality in the manufacture of fibre-reinforced cement products. However, the effect of sepiolite on flocculation and its interactions with the components of fibre cement are yet unknown. The aim of this research is to study the effects of sepiolite on the flocculation of different fibre-reinforced cement slurries induced by anionic polyacrylamides (A-PAMs). Flocculation and floc properties were studied by monitoring the chord size distribution in real time employing a focused beam reflectance measurement (FBRM) probe. The results show that sepiolite increases floc size and floc stability in fibre-cement suspensions. Sepiolite competes with fibres and clay for A-PAMs adsorption and its interaction with A-PAM improves flocculation of mineral particles.

Jarabo, Rocio; Fuente, Elena; Moral, Ana; Blanco, Angeles [Chemical Engineering Department, University Complutense of Madrid. Avda. Complutense s/n, Madrid 28040 (Spain); Izquierdo, Laura [I-D Department, TOLSA S.A., Rd. Vallecas-Mejorada del Campo, Km 1600, Madrid 28031 (Spain); Negro, Carlos, E-mail: cnegro@quim.ucm.e [Chemical Engineering Department, University Complutense of Madrid. Avda. Complutense s/n, Madrid 28040 (Spain)

2010-10-15

157

Assessing online collaborative learning: process and product  

Microsoft Academic Search

The assessment of online collaborative study presents new opportunities and challenges, both in terms of separating the process and product of collaboration, and in the support of skills development. The purpose of this paper is to explore the role of assessment with respect to the processes and products of online col- laborative study. It describes a qualitative case study of

Janet Macdonald

2003-01-01

158

Treatment and recycling of asbestos-cement containing waste  

Microsoft Academic Search

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

F. Colangelo; R. Cioffi; M. Lavorgna; L. Verdolotti; L. De Stefano

2011-01-01

159

FORMATION OF A DETACHED PLUME FROM A CEMENT PLANT  

EPA Science Inventory

A coordinated study of process, source emissions, and plume sampling was conducted at a coal-fired cement production plant. Both source and plume sampling consisted of particle and gas measurement and characterization. Particulate sampling of both the source and plume addressed p...

160

Ultrafast-Laser-Processed Zirconia and its Adhesion to Dental Cement  

Microsoft Academic Search

Hard zirconia ceramic in its hot-isostatically pressed constitution can be machined precisely and reproducibly using ultrafast lasers. However, the pulse overlap turns out to be of significant influ- ence on the resulting surface quality. This can be traced back to particulate process emission from the workpiece surface that influences subsequent pulses in the case of large pulse overlapping and can

Niko Bärsch; Stephan BARCIKOWSKI; Klaus BAIER

2008-01-01

161

Continuous process lithium grease production  

Microsoft Academic Search

1.It has been shown that grease made on a continuous process plant with a lithium stearate content of 8% by weight (optimum water content of the initial dispersion and free alkali content of 0.04% NaOH) can meet the GOST standard requirements for grease TsIATIM-201 containing 12% soap.2.The significant influence of free alkali content on the structure and properties of lithium

I. G. Fuks; V. V. Vainsntok; É. A. Smiotanko; Yu. N. Shekhter; G. G. Vinner; S. Yu. Omarov; B. N. Kartinin

1969-01-01

162

Assessment of the radiological impacts of utilizing coal combustion fly ash as main constituent in the production of cement.  

PubMed

The purpose of this study is to assess potential radiological impacts of utilizing pulverized fly ash (PFA) as a constituent in ordinary Portland cement. For this purpose, the activity concentrations of (226)Ra, (232)Th, and (40)K in samples of PFA and Portland cement containing 15%, 20%, and 25% by mass PFA were measured using gamma-ray spectrometry with HPGe detector. The mean activity concentrations of (226)Ra, (232)Th, and (40)K were found as 366.6, 113.7, and 460.2 Bq kg(?-?1), 94.2, 25.9, and 215.3 Bq kg(?-?1), 113.7, 34.3, and 238.3 Bq kg(?-?1), and 124.2, 41.8, and 279.3 Bq kg(?-?1) for the examined samples of PFA, Portland cement with 15%, 20%, and 25% by mass PFA, respectively. Radiological parameters such as radium equivalent activity, external exposure index (activity concentration index), internal dose index (alpha index), indoor absorbed gamma dose rate, and the corresponding the annually effective dose were assessed for Portland cement samples containing three percentages (15%, 20%, and 25%) by mass PFA. The results of assessment show that all Portland cement samples are within the safe limits recommended for building materials for dwellings. PMID:20714925

Turhan, Seref; Ar?kan, Ismail H; Köse, Abdullah; Varinlio?lu, Ahmet

2011-06-01

163

Process for impregnating a concrete or cement body with a polymeric material  

DOEpatents

A process for impregnating cementitious solids with polymeric materials by blending polymeric materials in a grout, allowing the grout to cure, and contacting the resulting solidified grout containing the polymeric materials with an organic mixture containing a monomer, a cross-linking agent and a catalyst. The mixture dissolves the polymerized particles and forms a channel for distributing the monomer throughout the network formed by the polymeric particles. The organic components are then cured to form a substantially water-impermeable mass.

Mattus, A.J.; Spence, R.D.

1988-05-04

164

Process for impregnating a concrete or cement body with a polymeric material  

DOEpatents

A process for impregnating cementitious solids with polymeric materials by blending polymeric materials in a grout, allowing the grout to cure, and contacting the resulting solidified grout containing the polymeric materials with an organic mixture containing a monomer, a cross-linking agent and a catalyst. The mixture dissolves the polymerized particles and forms a channel for distributing the monomer throughout the network formed by the polymeric particles. The organic components are then cured to form a substantially water-impermeable mass.

Mattus, Alfred J. (Kingston, TN); Spence, Roger D. (Clinton, TN)

1989-01-01

165

Cement industry: sustainability, challenges and perspectives  

Microsoft Academic Search

Cement-based materials, such as concrete and mortars, are used in extremely large amounts. For instance, in 2009 concrete\\u000a production was superior to 10 billion tons. Cement plays an important role in terms of economic and social relevance since\\u000a it is fundamental to build and improve infrastructure. On the other hand, this industry is also a heavy polluter. Cement production\\u000a releases

F. A. Rodrigues; I. Joekes

2011-01-01

166

Process for improving metal production in steelmaking processes  

DOEpatents

A process and apparatus for improving metal production in ironmaking and steelmaking processes is disclosed. The use of an inert metallic conductor in the slag containing crucible and the addition of a transition metal oxide to the slag are the disclosed process improvements. 6 figs.

Pal, U.B.; Gazula, G.K.M.; Hasham, A.

1996-06-18

167

Cement manufacture and the environment - Part I: Chemistry and technology  

USGS Publications Warehouse

Hydraulic (chiefly portland) cement is the binding agent in concrete and mortar and thus a key component of a country's construction sector. Concrete is arguably the most abundant of all manufactured solid materials. Portland cement is made primarily from finely ground clinker, which itself is composed dominantly of hydraulically active calcium silicate minerals formed through high-temperature burning of limestone and other materials in a kiln. This process requires approximately 1.7 tons of raw materials perton of clinker produced and yields about 1 ton of carbon dioxide (CO2) emissions, of which calcination of limestone and the combustion of fuels each contribute about half. The overall level of CO2 output makes the cement industry one of the top two manufacturing industry sources of greenhouse gases; however, in many countries, the cement industry's contribution is a small fraction of that from fossil fuel combustion by power plants and motor vehicles. The nature of clinker and the enormous heat requirements of its manufacture allow the cement industry to consume a wide variety of waste raw materials and fuels, thus providing the opportunity to apply key concepts of industrial ecology, most notably the closing of loops through the use of by-products of other industries (industrial symbiosis). In this article, the chemistry and technology of cement manufacture are summarized. In a forthcoming companion article (part II), some of the environmental challenges and opportunities facing the cement industry are described. Because of the size and scope of the U.S. cement industry, the analysis relies primarily on data and practices from the United States.

Van Oss, H. G.; Padovani, A. C.

2002-01-01

168

Comparison of modified sulfur cement and hydraulic cement for encapsulation of radioactive and mixed wastes  

Microsoft Academic Search

The majority of solidification\\/stabilization systems for low-level radioactive waste (LLW) and mixed waste, both in the commercial sector and at Department of Energy (DOE) facilities, utilize hydraulic cement (such as portland cement) to encapsulate waste materials and yield a monolithic solid waste form for disposal. A new and innovative process utilizing modified sulfur cement developed by the US Bureau of

P. D. Kalb; J. H. Heiser; P. Colombo

1990-01-01

169

Enhancing AFM process productivity through improved fixturing  

Microsoft Academic Search

Abrasive flow machining (AFM) is a non-conventional finishing process that deburrs and polishes by forcing an abrasive laden\\u000a media across the workpiece surface. The process embraces a wide range of applications from critical aerospace and medical\\u000a components to high-production volumes of parts. One serious limitation of this process is its low productivity in terms of\\u000a rate of improvement in surface

R. S. Walia; H. S. Shan; P. Kumar

2009-01-01

170

The pulsar planet production process  

NASA Technical Reports Server (NTRS)

Most plausible scenarios for the formation of planets around pulsars end with a disk of gas around the pulsar. The supplicant author then points to the solar system to bolster faith in the miraculous transfiguration of gas into planets. We here investigate this process of transfiguration. We derive analytic sequences of quasi-static disks which give good approximations to exact solutions of the disk diffusion equation with realistic opacity tables. These allow quick and efficient surveys of parameter space. We discuss the outward transfer of mass in accretion disks and the resulting timescale constraints, the effects of illumination by the central source on the disk and dust within it, and the effects of the widely different elemental compositions of the disks in the various scenarios, and their extensions to globular clusters. We point out where significant uncertainties exist in the appropriate grain opacities, and in the effect of illumination and winds from the neutron star.

Phinney, E. S.; Hansen, B. M. S.

1993-01-01

171

PRODUCTION OF CARBON PRODUCTS USING A COAL EXTRACTION PROCESS  

SciTech Connect

This Department of Energy National Energy Technology Laboratory sponsored project developed carbon products, using mildly hydrogenated solvents to extract the organic portion of coal to create synthetic pitches, cokes, carbon foam and carbon fibers. The focus of this effort was on development of lower cost solvents, milder hydrogenation conditions and improved yield in order to enable practical production of these products. This technology is needed because of the long-term decline in production of domestic feedstocks such as petroleum pitch and coal tar pitch. Currently, carbon products represents a market of roughly 5 million tons domestically, and 19 million tons worldwide. Carbon products are mainly derived from feedstocks such as petroleum pitch and coal tar pitch. The domestic supply of petroleum pitch is declining because of the rising price of liquid fuels, which has caused US refineries to maximize liquid fuel production. As a consequence, the long term trend has a decline in production of petroleum pitch over the past 20 years. The production of coal tar pitch, as in the case of petroleum pitch, has likewise declined significantly over the past two decades. Coal tar pitch is a byproduct of metallurgical grade coke (metcoke) production. In this industry, modern metcoke facilities are recycling coal tar as fuel in order to enhance energy efficiency and minimize environmental emissions. Metcoke production itself is dependent upon the production requirements for domestic steel. Hence, several metcoke ovens have been decommissioned over the past two decades and have not been replaced. As a consequence sources of coal tar are being taken off line and are not being replaced. The long-term trend is a reduction in coal tar pitch production. Thus import of feedstocks, mainly from Eastern Europe and China, is on the rise despite the relatively large transportation cost. To reverse this trend, a new process for producing carbon products is needed. The process must be economically competitive with current processes, and yet be environmentally friendly as well. The solvent extraction process developed uses mild hydrogenation of low cost oils to create powerful solvents that can dissolve the organic portion of coal. The insoluble portion, consisting mainly of mineral matter and fixed carbon, is removed via centrifugation or filtration, leaving a liquid solution of coal chemicals and solvent. This solution can be further refined via distillation to meet specifications for products such as synthetic pitches, cokes, carbon foam and fibers. The most economical process recycles 85% of the solvent, which itself is obtained as a low-cost byproduct from industrial processes such as coal tar or petroleum refining. Alternatively, processes have been developed that can recycle 100% of the solvent, avoiding any need for products derived from petroleum or coal tar.

Dady Dadyburjor; Philip R. Biedler; Chong Chen; L. Mitchell Clendenin; Manoj Katakdaunde; Elliot B. Kennel; Nathan D. King; Liviu Magean; Peter G. Stansberry; Alfred H. Stiller; John W. Zondlo

2004-08-31

172

Achieving Integrated Process and Product Safety Arguments  

NASA Astrophysics Data System (ADS)

Process-based certification standards such as IEC 61508 and DO-178B are often criticised for being highly prescriptive and impeding the adoption of new and novel methods and techniques. Rather than arguing safety based on compliance with a prescribed and fixed process, product-based certification standards require the submission of a well structured and reasoned safety case. Ideally, the safety case presents an argument that justifies the acceptability of safety based on product-specific and targeted evidence. However, the role of process assurance should not be underestimated even in product arguments. Lack of process assurance can undermine even the seemingly strongest product safety evidence. However, unlike the SIL-based process arguments, the process argument of the type we suggest are targeted and assured against specific safety case claims. In this way, a close association between product and process safety arguments can be carefully maintained. This paper shows how integrated process and product safety arguments can be achieved using the modular features of the Goal Structuring Notation (GSN).

Habli, Ibrahim; Kelly, Tim

173

Low-temperature ceramic radioactive waste form characteriztion of supercalcine-based monazite-cement composites  

SciTech Connect

Simulated radioactive waste solidification by a lower temperature ceramic (cement) process is being investigated. The monazite component (simulated by NdPO/sub 4/) of supercalcine-ceramic has been solidified in cement and found to generate a solid form with low leachability. Several types of commercial cements and modifications thereof were used. No detectable release of Nd or P was found through characterizing the products of accelerated hydrothermal leaching at 473/sup 0/K (200/sup 0/C) and 30.4 MPa (300 bars) pressure.

Roy, D.M.; Wakeley, L.D.; Atkinson, S.D.

1980-04-18

174

Natural cement as the precursor of Portland cement: Methodology for its identification  

SciTech Connect

When cements appeared in the 19th century, they took the place of traditional binding materials (lime, gypsum, and hydraulic lime) which had been used until that time. Early cements can be divided into two groups, natural and artificial (Portland) cements. Natural cements were introduced first, but their widespread usage was short-lived as they were quickly replaced by artificial cements (Portland), still the most important and predominant today. The main differences between natural and artificial cements arise during the manufacturing process. The final properties of the cements are greatly influenced by differences in the raw materials and burning temperatures employed. The aim of this paper is to assess the efficiency of traditional analytical techniques (petrographic microscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR)) used to differentiate natural and artificial cements.

Varas, M.J. [Institute of Economic Geology, Spanish Council for Scientific Research-Complutense University, Madrid (Spain)]. E-mail: mjvaras@geo.ucm.es; Alvarez de Buergo, M. [Institute of Economic Geology, Spanish Council for Scientific Research-Complutense University, Madrid (Spain); Fort, R. [Institute of Economic Geology, Spanish Council for Scientific Research-Complutense University, Madrid (Spain)

2005-11-15

175

PERFORMANCE OF LOW-COST VEGETABLE FIBRE-CEMENT COMPOSITES UNDER WEATHERING  

Microsoft Academic Search

Developed countries have achieved high performance wood fibre reinforced cement (WFRC) products by adopting elaborate technologies with high energy consumption processes. In attempting to reduce costs, researchers in developing countries have mainly concentrated on the use of natural strand reinforcement and simple production methods. Serious concerns have arisen regarding the durability of these lower technology products and consequently asbestos-based composites

H. SAVASTANO JR; P. G. WARDEN; R. S. P. COUTTS

176

Hydrothermally treated cement-based building materials. Past, present, and future  

Microsoft Academic Search

Hydrothermally cured or autoclaved cement-based building products have provided many challenges to researchers, manufacturers, and users since their inception nearly 100 years ago. The advantages, including the development of high strength within a few hours and a reduction of drying shrinkage, of the hydrothermal curing process have resulted in a variety of building products; inevitably, the technology of their production

A. Ray

2002-01-01

177

Surface pretreatment for prolonged survival of cemented tibial prosthesis components: full- vs. surface-cementation technique  

PubMed Central

Background One of few persisting problems of cemented total knee arthroplasty (TKA) is aseptic loosening of tibial component due to degradation of the interface between bone cement and metallic tibial shaft component, particularly for surface cemented tibial components. Surface cementation technique has important clinical meaning in case of revision and for avoidance of stress shielding. Degradation of the interface between bone cement and bone may be a secondary effect due to excessive crack formation in bone cement starting at the opposite metallic surface. Methods This study was done to prove crack formation in the bone cement near the metallic surface when this is not coated. We propose a newly developed coating process by PVD layering with SiOx to avoid that crack formation in the bone cement. A biomechanical model for vibration fatigue test was done to simulate the physiological and biomechanical conditions of the human knee joint and to prove excessive crack formation. Results It was found that coated tibial components showed a highly significant reduction of cement cracking near the interface metal/bone cement (p < 0.01) and a significant reduction of gap formation in the interface metal-to-bone cement (p < 0.05). Conclusion Coating dramatically reduces hydrolytic- and stress-related crack formation at the prosthesis interface metal/bone cement. This leads to a more homogenous load transfer into the cement mantle which should reduce the frequency of loosening in the interfaces metal/bone cement/bone. With surface coating of the tibial component it should become possible that surface cemented TKAs reveal similar loosening rates as TKAs both surface and stem cemented. This would be an important clinical advantage since it is believed that surface cementing reduces metaphyseal bone loss in case of revision and stress shielding for better bone health.

Marx, Rudolf; Qunaibi, Mutaz; Wirtz, Dieter Christian; Niethard, Fritz Uwe; Mumme, Thorsten

2005-01-01

178

Mariner 9-Image processing and products  

USGS Publications Warehouse

The purpose of this paper is to describe the system for the display, processing, and production of image-data products created to support the Mariner 9 Television Experiment. Of necessity, the system was large in order to respond to the needs of a large team of scientists with a broad scope of experimental objectives. The desire to generate processed data products as rapidly as possible to take advantage of adaptive planning during the mission, coupled with the complexities introduced by the nature of the vidicon camera, greatly increased the scale of the ground-image processing effort. This paper describes the systems that carried out the processes and delivered the products necessary for real-time and near-real-time analyses. References are made to the computer algorithms used for the, different levels of decalibration and analysis. ?? 1973.

Levinthal, E. C.; Green, W. B.; Cutts, J. A.; Jahelka, E. D.; Johansen, R. A.; Sander, M. J.; Seidman, J. B.; Young, A. T.; Soderblom, L. A.

1973-01-01

179

China: Emissions pattern of the world leader in CO2 emissions from fossil fuel consumption and cement production  

Microsoft Academic Search

Release of carbon dioxide (CO2) from fossil fuel combustion and cement manufacture is the primary anthropogenic driver of climate change. Our best estimate is that China became the largest national source of CO2 emissions during 2006. Previously, the United States (US) had occupied that position. However, the annual emission rate in the US has remained relatively stable between 2001–2006 while

Jay S. Gregg; Robert J. Andres; Gregg Marland

2008-01-01

180

China: Emissions pattern of the world leader in CO2 emissions from fossil fuel consumption and cement production  

Microsoft Academic Search

Release of carbon dioxide (CO2) from fossil fuel combustion and cement manufacture is the primary anthropogenic driver of climate change. Our best estimate is that China became the largest national source of CO2 emissions during 2006. Previously, the United States (US) had occupied that position. However, the annual emission rate in the US has remained relatively stable between 2001-2006 while

Jay S. Gregg; Robert Joseph Andres; Gregg Marland

2008-01-01

181

Processing and Valorization of Secondary Winery Products  

Microsoft Academic Search

The information regarding the composition of secondary winery products (mark, yeasts, vinasse, grape seeds, superior fractions\\u000a obtained at wine distillation, waste waters, etc.) and several complex technologies of processing these products are presented,\\u000a such as: production technologies for tartaric acid and its derivatives; technologies of synthesis of medicinal and agricultural\\u000a preparations obtained on the basis of the biologically active compound

Gheorghe Duca; Maria Gon?a; Aliona Mereu?a

182

Quality control of polymer production processes  

Microsoft Academic Search

For the polymer production industries, the competitive edge will come from the technology that excels in controlling the polymer properties in a consistent way over the entire plant and in maximizing the production performance while keeping safety regulations. Based on the experience in applying advanced process control and scheduling schemes to industrial polyolefin polymerization plants, the state of the art

Masahiro Ohshima; Masataka Tanigaki

2000-01-01

183

Production Process for Strong, Light Ceramic Tiles  

NASA Technical Reports Server (NTRS)

Proportions of ingredients and sintering time/temperature schedule changed. Production process for lightweight, high-strength ceramic insulating tiles for Space Shuttle more than just scaled-up version of laboratory process for making small tiles. Boron in aluminum borosilicate fibers allows fusion at points where fibers contact each other during sintering, thereby greatly strengthening tiles structure.

Holmquist, G. R.; Cordia, E. R.; Tomer, R. S.

1985-01-01

184

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

SciTech Connect

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 year); (5) the amount of production of cement by type and grade (in tonnes per year); (6) the electricity generated onsite; and, (7) the energy used by fuel type; and, the amount (in RMB per year) spent on energy. The tool offers the user the opportunity to do a quick assessment or a more detailed assessment--this choice will determine the level of detail of the energy input. The detailed assessment will require energy data for each stage of production while the quick assessment will require only total energy used at the entire facility (see Section 6 for more details on quick versus detailed assessments). The benchmarking tool provides two benchmarks--one for Chinese best practices and one for international best practices. Section 2 describes the differences between these two and how each benchmark was calculated. The tool also asks for a target input by the user for the user to set goals for the facility.

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

2008-07-30

185

Influence of lithium-based products proposed for counteracting ASR on the chemistry of pore solution and cement hydrates  

Microsoft Academic Search

Low- and high-alkali cement pastes were made with or without LiNO3 or a Li-bearing glass. The [Li]\\/[Na+K] molar ratio was kept constant to 0.74. The specimens were stored at 23, 38, and 60 °C in sealed containers. After 3, 7, 28, and 91 days, their pore solutions were extracted and analysed, and their residual water contents were obtained by drying.

M. A. Bérubé; C. Tremblay; B. Fournier; M. D. Thomas; D. B. Stokes

2004-01-01

186

Immobilisation of heavy metal in cement-based solidification/stabilisation: A review  

SciTech Connect

Heavy metal-bearing waste usually needs solidification/stabilization (s/s) prior to landfill to lower the leaching rate. Cement is the most adaptable binder currently available for the immobilisation of heavy metals. The selection of cements and operating parameters depends upon an understanding of chemistry of the system. This paper discusses interactions of heavy metals and cement phases in the solidification/stabilisation process. It provides a clarification of heavy metal effects on cement hydration. According to the decomposition rate of minerals, heavy metals accelerate the hydration of tricalcium silicate (C{sub 3}S) and Portland cement, although they retard the precipitation of portlandite due to the reduction of pH resulted from hydrolyses of heavy metal ions. The chemical mechanism relevant to the accelerating effect of heavy metals is considered to be H{sup +} attacks on cement phases and the precipitation of calcium heavy metal double hydroxides, which consumes calcium ions and then promotes the decomposition of C{sub 3}S. In this work, molecular models of calcium silicate hydrate gel are presented based on the examination of {sup 29}Si solid-state magic angle spinning/nuclear magnetic resonance (MAS/NMR). This paper also reviews immobilisation mechanisms of heavy metals in hydrated cement matrices, focusing on the sorption, precipitation and chemical incorporation of cement hydration products. It is concluded that further research on the phase development during cement hydration in the presence of heavy metals and thermodynamic modelling is needed to improve effectiveness of cement-based s/s and extend this waste management technique.

Chen, Q.Y. [School of Environmental Science and Engineering, Donghua University, Shanghai 200051 (China)], E-mail: qychen@dhu.edu.cn; Tyrer, M. [Department of Materials, Imperial College of Science, Technology and Medicine, London SW7 4AZ (United Kingdom); Hills, C.D. [Centre for Contaminated Land Remediation, Medway School of Science, University of Greenwich, Chatham Maritime, Kent ME4 4TB (United Kingdom); Yang, X.M. [School of Environmental Science and Engineering, Donghua University, Shanghai 200051 (China); Carey, P. [Centre for Contaminated Land Remediation, Medway School of Science, University of Greenwich, Chatham Maritime, Kent ME4 4TB (United Kingdom)

2009-01-15

187

Renewable hydrogen production for fossil fuel processing  

SciTech Connect

The objective of this mission-oriented research program is the production of renewable hydrogen for fossil fuel processing. This program will build upon promising results that have been obtained in the Chemical Technology Division of Oak Ridge National Laboratory on the utilization of intact microalgae for photosynthetic water splitting. In this process, specially adapted algae are used to perform the light-activated cleavage of water into its elemental constituents, molecular hydrogen and oxygen. The great potential of hydrogen production by microalgal water splitting is predicated on quantitative measurement of their hydrogen-producing capability. These are: (1) the photosynthetic unit size of hydrogen production; (2) the turnover time of photosynthetic hydrogen production; (3) thermodynamic efficiencies of conversion of light energy into the Gibbs free energy of molecular hydrogen; (4) photosynthetic hydrogen production from sea water using marine algae; (5) the original development of an evacuated photobiological reactor for real-world engineering applications; (6) the potential for using modern methods of molecular biology and genetic engineering to maximize hydrogen production. The significance of each of these points in the context of a practical system for hydrogen production is discussed. This program will be enhanced by collaborative research between Oak Ridge National Laboratory and senior faculty members at Duke University, the University of Chicago, and Iowa State University. The special contribution that these organizations and faculty members will make is access to strains and mutants of unicellular algae that will potentially have useful properties for hydrogen production by microalgal water splitting.

Greenbaum, E.

1994-09-01

188

Process for preparing a proteinaceous food product  

US Patent & Trademark Office Database

A process for preparing a proteinaceous food product comprises passing a wet dough of a mammalian and/or avian meat protein, at least part of which is functionally inert protein, between a pair of oppositely rotating rollers to form a sheet of said food product. The functionally inert protein may have been cooked or otherwise treated to impart to the protein one or more characteristics of cooked protein and/or may comprise inert scleroprotein.

1991-12-10

189

Calcium Silicate Cement Sorbent for H sub 2 S Removal and Improved Gasification Processes. Annual Progress Report, October 1, 1981-September 30, 1982.  

National Technical Information Service (NTIS)

Commercial calcium silicate bearing Portland cement type III (PC III), in the form of agglomerated cement sorbent (ACS) pellets, is being investigated for in-situ desulfurization of fuel gases and for improved coal gasification. The preparation procedure ...

H. J. Yoo M. Steinberg

1982-01-01

190

TIP-Converter Process: A Ductile Iron Production Process.  

National Technical Information Service (NTIS)

Using the TIP-converter process for ductile iron production at Pori Foundry has resulted in a number of advantages. Higher magnesium recovery has permitted the use of less nodulizing alloy. Less fume and glare, reduced temperature loss during magnesium tr...

C. Chen J. J. Vuorinen Y. Julin

1991-01-01

191

Synthesis and hydration of calcium sulfoaluminate-belite cements with varied phase compositions  

Microsoft Academic Search

The production of portland cement is energy intensive and contributes significantly to greenhouse gas emissions. One method\\u000a of reducing the environmental impact of concrete production is the use of an alternative binder, such as calcium sulfoaluminate-belite\\u000a (CSAB) cement. The relatively low lime requirement of CSAB cement compared to portland cement reduces energy consumption and\\u000a carbon dioxide emissions from cement production.

Irvin A. ChenMaria; Maria C. G. Juenger

2011-01-01

192

Influence of granule properties and concentration on cork-cement compatibility  

Microsoft Academic Search

Cork granules are produced as by-products and waste by the cork processing industries that make ‘bottle stoppers’ as a main product. These granules are of low density and could be used as lightweight aggregates for making concrete. This paper describes an investigation carried out to assess the compatibility of cork granules with cement for the manufacture of lightweight cementitious composites.

Sukhdeo R. Karade; Mark Irle; Kevin Maher

2006-01-01

193

Production of strange particles in hadronization processes  

SciTech Connect

Strange particles provide an important tool for the study of the color confinement mechanisms involved in hadronization processes. We review data on inclusive strange-particle production and on correlations between strange particles in high-energy reactions, and discuss phenomenological models for parton fragmentation. 58 refs., 24 figs.

Hofmann, W.

1987-08-01

194

Scleroglucan: Fermentative Production, Downstream Processing and Applications  

Microsoft Academic Search

Summary Exopolysaccharides produced by a variety of microorganisms find multifarious indus- trial applications in foods, pharmaceutical and other industries as emulsifiers, stabilizers, binders, gelling agents, lubricants, and thickening agents. One such exopolysaccharide is scleroglucan, produced by pure culture fermentation from filamentous fungi of genus Scle- rotium. The review discusses the properties, fermentative production, downstream process- ing and applications of scleroglucan.

Shrikant A. Survase; Parag S. Saudagar; Ishwar B. Bajaj; Rekha S. Singhal

195

Optimization of a Paint Production Process.  

National Technical Information Service (NTIS)

The project will be conducted for the U.S. Army TARDEC Survivability Group. The main objective of this project is to integrate a pixilated camouflage paint pattern into the production process for the Future Combat Systems (FCS). Currently, military system...

P. Najjar

2009-01-01

196

Assessing Online Collaborative Learning: Process and Product.  

ERIC Educational Resources Information Center

Explores the role of assessment with respect to the processes and products of online collaborative study. Describes a qualitative case study of staff and student perspectives on two United Kingdom Open University courses, which have used online collaborative assessment, and discusses results which underline the importance of assessment in ensuring…

Macdonald, Janet

2003-01-01

197

Syllables as Processing Units in Handwriting Production  

ERIC Educational Resources Information Center

This research focused on the syllable as a processing unit in handwriting. Participants wrote, in uppercase letters, words that had been visually presented. The interletter intervals provide information on the timing of motor production. In Experiment 1, French participants wrote words that shared the initial letters but had different syllable…

Kandel, Sonia; Alvarez, Carlos J.; Vallee, Nathalie

2006-01-01

198

PROCESS FOR THE PRODUCTION OF URANIUM MONOCARBIDE  

Microsoft Academic Search

A process for the production of a low-graphite-content UC at relatively ; low temperatures is patented. A U--C or UOâ--C mixture is carburized in a ; vacuum at a temperature below 1600 deg C in a metallic oxide container. The ; metallic oxide should be one that has substantially no reaction with U, UOâ; , and C below 1600 deg

R. Kohlermann; W. Dubel; W. Flurschutz

1963-01-01

199

Written Composition: Process, Product, Program. Monograph Series.  

ERIC Educational Resources Information Center

Intended for teachers and administrators, this collection of essays focuses on the dual meaning of practice--practice of writing skills, and teaching practices in composition instruction. The process section focuses on the types of activities that build composition skills. The product and program sections shift focus to professional practice, the…

Chew, Charles R., Ed.; Schlawin, Sheila A., Ed.

200

Thermoradiation processes of energy-carrier production  

NASA Astrophysics Data System (ADS)

Thermoradiation processes in the production of hydrogen and carbon monoxide from water vapor and CO2 are discussed. An radiolysis experiment was conducted using a one-pass flow system and an electron accelerator (with energy of 3 Me V), according to parameters of dose rate, regent-radiation contact time, and temperature (700 deg). Steady-state concentrations of H2 and CO were found to correspond to 20 and 40 percent radiation energy-product and energy conversion, respectively. The results of the experiment permit an accurate determination of the optimal parameters of the conversion process and an estimate of the relative efficiencies of chemonuclear and electrochemical methods (plasmolysis and electrolysis) of H2 and CO production using nuclear piles.

Dzantiev, B. G.; Ermakov, A. N.; Zhitomirskii, V. M.; Popov, V. N.

201

Baghouse dust used in clinkerization of portland cements  

Microsoft Academic Search

Many industrial materials considered essential for supporting a better quality of life consume large amounts of energy for their production. Ordinary portland cement (OPC) is used widely as a building material, and its manufacture consumes much energy. In India, the cost of energy accounts for >40% of the total cost of cement manufacture. The cost to manufacture cement is expected

N. B. Singh; K. N. Bhattacharjee; A. K. Shukla

1995-01-01

202

Properties of volcanic pumice based cement and lightweight concrete  

Microsoft Academic Search

The results of investigations on the suitability of using volcanic pumice (VP) as cement replacement material and as coarse aggregate in lightweight concrete production are reported. Tests were conducted on cement by replacing 0% to 25% of cement by weight and on concrete by replacing 0% to 100% of coarse aggregate by volume. The physical and chemical properties of VP

Khandaker M Anwar Hossain

2004-01-01

203

Process for biodiesel production from Cryptococcus curvatus.  

PubMed

The objective of the current report is process optimization for economical production of lipids by the well known oleaginous yeast Cryptococcus curvatus and conversion of the lipids to biodiesel. A high cell density fed-batch cultivation on low cost substrate viz. crude glycerol resulted in a dry biomass and oil yield of up to 69 g/L and 48% (w/w), respectively. The process was scaled up easily to 26 L. The oil extraction process was also optimized using environmentally safe solvents. The oil profile indicated a high oleic acid content followed by palmitic acid, stearic acid and linoleic acid. The oil was trans-esterified to biodiesel and thoroughly characterized. This is the first end to end report on production of biodiesel from the C. curvatus oil. PMID:21930373

Thiru, Meikandhan; Sankh, Santosh; Rangaswamy, Vidhya

2011-11-01

204

Multiphase Processing of Isoprene Oxidation Products - Kinetic and Product Studies  

NASA Astrophysics Data System (ADS)

Isoprene represents a significant fraction of NMHC in the troposphere with recently estimated emission rates of 500-750 TgC yr-1 (1). Due to its enormous source strength, the fate of isoprene and its degradation products is important in atmospheric processes. Possible ascendancies of such oxidation processes are the regional ozone and secondary organic aerosol (SOA) formation. Some aspects of SOA formation from isoprene and its degradation products have already been studied by chamber studies (2,3). Aqueous phase oxidation processes which may occur after phase transfer of ‘early’ oxidation products are often neglected. But these processes provide a potentially important source for organic particle mass constituents such as carboxylic acids. The majority of existing aqueous phase modelling studies focus only on ‘later’ products such as methylglyoxal and oxalic acid. Yet, a recent field study reports much higher aqueous phase concentrations of some ‘earlier’ isoprene oxidation products including methacrolein (MACR) and methyl vinyl ketone (MVK) than expected (4). This indicates a possibly underestimated importance of multiphase chemical processes in the course of the isoprene oxidation as a source for the production of organic particle mass together with known ‘heterogeneous processes’ such as the direct condensation of low-volatility products from gas phase processes onto existing particle surfaces. In order to implement the isoprene multiphase chemistry in atmospheric models detailed kinetic and mechanistic studies are needed. Hence, the temperature dependence of MACR, MVK, methacrylic acid and acrylic acid exposed to NO3, SO4- and OH radicals in the aqueous phase was investigated. The measurements were performed using a laser-photolysis laser long path absorption technique. The analysis confirmed in all cases the much higher reactivity of the OH radical in comparison to SO4- and NO3 radicals. The temperature dependence is most distinct for NO3 radical reactions and weakest for those with SO4-. For the identification of oxidation products different analytical techniques were applied such as HPLC-UV, CE-UV and HPLC-MS after laser flash photolysis. All samples were analyzed offline with and without prior derivatization steps. In order to purify and enrich the samples, a solid phase extraction was performed before analysis. Mainly identified reaction products are functionalized carbonyl compounds and carboxylic acids. The kinetic and mechanistic data obtained will help to improve existing aqueous phase isoprene oxidation mechanisms. With the extended mechanism the role of multiphase processes for the formation of organic particle constituents such as carboxylic acids from the isoprene oxidation can be much better assessed in the future. (1) A. Guenther, et al. (2006). ACP, 6, 3181. (2) J. H. Kroll, et al. (2006). ES&T, 40, 1869. (3) J. D. Surratt, et al. (2007). ES&T, 41, 5363. (4) D. van Pinxteren, et al. (2005). Atmos. Environ, 39, 4305.

Hoffmann, D.; Schoene, L.; Schindelka, J.; Herrmann, H.

2010-12-01

205

Early age hydration and pozzolanic reaction in natural zeolite blended cements: Reaction kinetics and products by in situ synchrotron X-ray powder diffraction  

SciTech Connect

The in situ early-age hydration and pozzolanic reaction in cements blended with natural zeolites were investigated by time-resolved synchrotron X-ray powder diffraction with Rietveld quantitative phase analysis. Chabazite and Na-, K-, and Ca-exchanged clinoptilolite materials were mixed with Portland cement in a 3:7 weight ratio and hydrated in situ at 40 {sup o}C. The evolution of phase contents showed that the addition of natural zeolites accelerates the onset of C{sub 3}S hydration and precipitation of CH and AFt. Kinetic analysis of the consumption of C{sub 3}S indicates that the enveloping C-S-H layer is thinner and/or less dense in the presence of alkali-exchanged clinoptilolite pozzolans. The zeolite pozzolanic activity is interpreted to depend on the zeolite exchangeable cation content and on the crystallinity. The addition of natural zeolites alters the structural evolution of the C-S-H product. Longer silicate chains and a lower C/S ratio are deduced from the evolution of the C-S-H b-cell parameter.

Snellings, R., E-mail: ruben.snellings@ees.kuleuven.b [Department of Earth and Environmental Sciences, Katholieke Universiteit Leuven, Celestijnenlaan 200E, B-3001 Heverlee (Belgium); Mertens, G. [Department of Earth and Environmental Sciences, Katholieke Universiteit Leuven, Celestijnenlaan 200E, B-3001 Heverlee (Belgium); Cizer, O. [Department of Civil Engineering, Katholieke Universiteit Leuven, Kasteelpark Arenberg 40, B-3001 Heverlee (Belgium); Elsen, J. [Department of Earth and Environmental Sciences, Katholieke Universiteit Leuven, Celestijnenlaan 200E, B-3001 Heverlee (Belgium)

2010-12-15

206

Roadmap for Process Heating Technology. Priority Research and Development Goals and Near-Term Non-Research Goals to Improve Industrial Process Heating.  

National Technical Information Service (NTIS)

Process heating technologies supply heat to nearly all manufacturing processes. Whether in the production of materials such as steel, cement, and composites or in the manufacture of valueadded products such as electronics, computer chips, cosmetics, and t...

2001-01-01

207

Eliciting information for product modeling using process modeling  

Microsoft Academic Search

A product model is a formal and structured definition of product information. The most common procedure for defin- ing a product data model is to first describe the business and\\/or engineering process in a formal process model, then to create a product data model based on the process model. However, there is a logical gap between process modeling and product

Ghang Lee; Charles M. Eastman; Rafael Sacks

2007-01-01

208

Leach studies on cement-solidified ion exchange resins from decontamination processes at operating nuclear power stations  

SciTech Connect

The effects of varying pH and leachant compositions on the physical stability and leachability of radionuclides and chelating agents were determined for cement-solidified decontamination ion-exchange resin wastes collected from two operating commercial light water reactors. Small scale waste-form specimens were collected during waste solidifications performed at the Brunswick Steam Electric Plant Unit 1 and at the James A. FitzPatrick Nuclear Power Station. The collected specimens were leach tested, and their compressive strength was measured in accordance with the Nuclear Regulatory Commission's Technical Position on Waste Form'' (Revision 1), from the Low-Level Waste Management Branch. Leachates from these studies were analyzed for radionuclides, selected transition metals, and chelating agents to assess the leachability of these waste form constituents. Leachants used for the study were deionized water, simulated seawater, and groundwater compositions similar to those found at Barnwell, South Carolina and Hanford, Washington. Results of this study indicate that initial leachant pH does not affect leachate pH or releases from cement-solidified decontamination ion-exchange resin waste forms. However, differences in leachant composition and the presence of chelating agents may affect the releases of radionuclides and chelating agents. In addition, results from this study indicate that the cumulative releases of radionuclides and chelating agents observed for forms that disintegrated were similar to those for forms that maintained their general physical integrity.

McIsaac, C.V.; Akers, D.W.; McConnell, J.W.; Morcos, N.

1992-01-01

209

Leach studies on cement-solidified ion exchange resins from decontamination processes at operating nuclear power stations  

SciTech Connect

The effects of varying pH and leachant compositions on the physical stability and leachability of radionuclides and chelating agents were determined for cement-solidified decontamination ion-exchange resin wastes collected from two operating commercial light water reactors. Small scale waste-form specimens were collected during waste solidifications performed at the Brunswick Steam Electric Plant Unit 1 and at the James A. FitzPatrick Nuclear Power Station. The collected specimens were leach tested, and their compressive strength was measured in accordance with the Nuclear Regulatory Commission`s ``Technical Position on Waste Form`` (Revision 1), from the Low-Level Waste Management Branch. Leachates from these studies were analyzed for radionuclides, selected transition metals, and chelating agents to assess the leachability of these waste form constituents. Leachants used for the study were deionized water, simulated seawater, and groundwater compositions similar to those found at Barnwell, South Carolina and Hanford, Washington. Results of this study indicate that initial leachant pH does not affect leachate pH or releases from cement-solidified decontamination ion-exchange resin waste forms. However, differences in leachant composition and the presence of chelating agents may affect the releases of radionuclides and chelating agents. In addition, results from this study indicate that the cumulative releases of radionuclides and chelating agents observed for forms that disintegrated were similar to those for forms that maintained their general physical integrity.

McIsaac, C.V.; Akers, D.W.; McConnell, J.W.; Morcos, N.

1992-08-01

210

Effects of DCPD Cement Chemistry on Degradation Properties and Cytocompatibility: Comparison of MCPM/?-TCP and MCPM/HA Formulations  

PubMed Central

Dicalcium phosphate dihydrate (DCPD) cements are attractive biomaterials for bone repair, and a number of different DCPD cement formulations have been proposed in the literature. In this study we have specifically compared monocalcium phosphate monohydrate (MCPM)/hydroxyapatite (HA) and MCPM/?-tricalcium phosphate (?-TCP) formulations to test the hypothesis that DCPD cement chemistry affects the degradation properties and cytocompatibility of the cement. Using simple in vitro models we found that MCPM/?-TCP formulations degraded primarily by DCPD dissolution, which was associated with a slight pH drop and relatively low mass loss. Cytocompatibility testing of cement conditioned culture media revealed no significant change in cell viability relative to the negative control for all of the MCPM/?-TCP formulations. In contrast, the MCPM/HA formulations were prone to undergo rapid conversion of DCPD to HA, resulting in a sharp pH drop and extensive mass loss. A stoichiometric excess of HA in the cement was found to accelerate the conversion process, and significant cytotoxicity was observed for the MCPM/HA formulations containing excess HA. Collectively, these results show that, although the product of the setting reaction is the same, DCPD cements produced with MCPM/HA and MCPM/?-TCP formulations differ significantly in their degradation properties and cytocompatibility. These differences may have important implications for the selection of a DCPD cement formulation for clinical application.

Alge, Daniel L.; Goebel, W. Scott; Chu, Tien-Min Gabriel

2013-01-01

211

The hydration phase and pore structure formation in the blends of sulfoaluminate-belite cement with Portland cement  

Microsoft Academic Search

Sulfoaluminate-belite (SAB) cements are an attractive class of low-energy cements from the viewpoint of saving energy and releasing less CO2 into the atmosphere during their production. Their hydraulic activity, however, does not match that of the ordinary Portland cement (PC) and needs improvement before they can be used on their own. However, SAB cements when blended with PC have the

I Janotka; L' Kraj?i; A Ray; S. C Mojumdar

2003-01-01

212

Modelling elasticity of a hydrating cement paste  

Microsoft Academic Search

Concrete is a complex multi-scale composite involving multi-physics processes. As it is the only evolving component of concrete, the cement paste has a major influence on the mechanical properties of concrete at early age. This paper focuses on the increase of the elastic properties of a cement paste during its hydration. The homogenization theory for disordered media is used in

Julien Sanahuja; Luc Dormieux; Gilles Chanvillard

2007-01-01

213

Multiphase Flow Modeling of Biofuel Production Processes  

SciTech Connect

As part of the Idaho National Laboratory's (INL's) Secure Energy Initiative, the INL is performing research in areas that are vital to ensuring clean, secure energy supplies for the future. The INL Hybrid Energy Systems Testing (HYTEST) Laboratory is being established to develop and test hybrid energy systems with the principal objective to safeguard U.S. Energy Security by reducing dependence on foreign petroleum. HYTEST involves producing liquid fuels in a Hybrid Energy System (HES) by integrating carbon-based (i.e., bio-mass, oil-shale, etc.) with non-carbon based energy sources (i.e., wind energy, hydro, geothermal, nuclear, etc.). Advances in process development, control and modeling are the unifying vision for HES. This paper describes new modeling tools and methodologies to simulate advanced energy processes. Needs are emerging that require advanced computational modeling of multiphase reacting systems in the energy arena, driven by the 2007 Energy Independence and Security Act, which requires production of 36 billion gal/yr of biofuels by 2022, with 21 billion gal of this as advanced biofuels. Advanced biofuels derived from microalgal biomass have the potential to help achieve the 21 billion gal mandate, as well as reduce greenhouse gas emissions. Production of biofuels from microalgae is receiving considerable interest due to their potentially high oil yields (around 600 gal/acre). Microalgae have a high lipid content (up to 50%) and grow 10 to 100 times faster than terrestrial plants. The use of environmentally friendly alternatives to solvents and reagents commonly employed in reaction and phase separation processes is being explored. This is accomplished through the use of hydrothermal technologies, which are chemical and physical transformations in high-temperature (200-600 C), high-pressure (5-40 MPa) liquid or supercritical water. Figure 1 shows a simplified diagram of the production of biofuels from algae. Hydrothermal processing has significant advantages over other biomass processing methods with respect to separations. These 'green' alternatives employ a hybrid medium that, when operated supercritically, offers the prospect of tunable physicochemical properties. Solubility can be rapidly altered and phases partitioned selectively to precipitate or dissolve certain components by altering temperature or pressure in the near-critical region. The ability to tune the solvation properties of water in the highly compressible near-critical region facilitates partitioning of products or by-products into separate phases to separate and purify products. Since most challenges related to lipid extraction are associated with the industrial scale-up of integrated extraction systems, the new modeling capability offers the prospect of addressing previously untenable scaling issues.

D. Gaston; D. P. Guillen; J. Tester

2011-06-01

214

MULTIMEDIA ASSESSMENT AND ENVIRONMENTAL RESEARCH NEEDS OF THE CEMENT INDUSTRY  

EPA Science Inventory

This project was initiated to obtain a comprehensive assessment of the cement industry and its environmental research needs. This report contains a profile of the U.S. cement industry; an analysis of the cement manufacturing processes; a discussion of waste stream characteristics...

215

The effects of the mechanical-chemical stabilization process for municipal solid waste incinerator fly ash on the chemical reactions in cement paste.  

PubMed

A water extraction process can remove the soluble salts present in municipal solid waste incinerator (MSWI) fly ash, which will help to increase the stability of the synthetic materials produced from the MSWI fly ash. A milling process can be used to stabilize the heavy metals found in the extracted MSWI fly ash (EA) leading to the formation of a non-hazardous material. This milled extracted MSWI fly ash (MEA) was added to an ordinary Portland cement (OPC) paste to induce pozzolanic reactions. The experimental parameters included the milling time (96h), water to binder ratios (0.38, 0.45, and 0.55), and curing time (1, 3, 7 and 28 days). The analysis procedures included inductively coupled plasma atomic emission spectroscopy (ICP/AES), BET, mercury intrusion porosimetry (MIP), X-ray diffraction (XRD), and nuclear magnetic resonance (NMR) imaging. The results of the analyses indicate that the milling process helped to stabilize the heavy metals in the MEA, with an increase in the specific surface area of about 50times over that of OPC. The addition of the MEA to the OPC paste decreased the amount of Ca(OH)2 and led to the generation of calcium-silicate-hydrates (C-S-H) which in turned increased the amount of gel pores and middle sized pores in the cement. Furthermore, a comparison shows an increase in the early and later strength over that of OPC paste without the addition of the milled extracted ash. In other words, the milling process could stabilize the heavy metals in the MEA and had an activating effect on the MEA, allowing it to partly substitute OPC in OPC paste. PMID:23375995

Chen, Cheng-Gang; Sun, Chang-Jung; Gau, Sue-Huai; Wu, Ching-Wei; Chen, Yu-Lun

2013-04-01

216

Measurement of transient and residual stresses during polymerization of bone cement for cemented hip implants.  

PubMed

The initial fixation of a cemented hip implant relies on the strength of the interface between the stem, bone cement and adjacent bone. Bone cement is used as grouting material to fix the prosthesis to the bone. The curing process of bone cement is an exothermic reaction where bone cement undergoes volumetric changes that will generate transient stresses resulting in residual stresses once polymerization is completed. However, the precise magnitude of these stresses is still not well documented in the literature. The objective of this study is to develop an experiment for the direct measurement of the transient and residual radial stresses at the stem-cement interface generated during cement polymerization. The idealized femoral-cemented implant consists of a stem placed inside a hollow cylindrical bone filled with bone cement. A sub-miniature load cell is inserted inside the stem to make a direct measurement of the radial compressive forces at the stem-cement interface, which are then converted to radial stresses. A thermocouple measures the temperature evolution during the polymerization process. The results show the evolution of stress generation corresponding to volumetric changes in the cement. The effect of initial temperature of the stem and bone as well as the cement-bone interface condition (adhesion or no adhesion) on residual radial stresses is investigated. A maximum peak temperature of 70 degrees C corresponds to a peak in transient stress during cement curing. Maximum radial residual stresses of 0.6 MPa in compression are measured for the preheated stem. PMID:18692188

Nuño, N; Madrala, A; Plamondon, D

2008-08-28

217

Estimates of global, regional, and national annual CO{sub 2} emissions from fossil-fuel burning, hydraulic cement production, and gas flaring: 1950--1992  

SciTech Connect

This document describes the compilation, content, and format of the most comprehensive C0{sub 2}-emissions database currently available. The database includes global, regional, and national annual estimates of C0{sub 2} emissions resulting from fossil-fuel burning, cement manufacturing, and gas flaring in oil fields for 1950--92 as well as the energy production, consumption, and trade data used for these estimates. The methods of Marland and Rotty (1983) are used to calculate these emission estimates. For the first time, the methods and data used to calculate CO, emissions from gas flaring are presented. This C0{sub 2}-emissions database is useful for carbon-cycle research, provides estimates of the rate at which fossil-fuel combustion has released C0{sub 2} to the atmosphere, and offers baseline estimates for those countries compiling 1990 C0{sub 2}-emissions inventories.

Boden, T.A.; Marland, G. [Oak Ridge National Lab., TN (United States); Andres, R.J. [University of Alaska, Fairbanks, AK (United States). Inst. of Northern Engineering

1995-12-01

218

Process for recovery of aluminum from carbonaceous waste products  

SciTech Connect

A carbonaceous waste product, preferably containing 30 to 60% mineral substances, 35 to 55% carbonaceous materials, 5 to 20% water, and having a calorific value of 2,000 to 3,500 k cal/kg is fired to produce thermal energy and a combustion residue. The residue is adjusted, if necessary, by addition of mineral containing additives so that it contains 15 to 50% alumina, 15 to 20% silica and 13 to 45% other oxides (mainly iron oxide, manganese oxide and calcium oxide). Sufficient limestone is added to produce a mixture containing 1.8 to 2.2 moles of calcium oxide per mole of silica and 1.1 to 1.3 moles of calcium oxide per mole of alumina. The mixture is then sintered. The total energy requirements of the sintering step are supplied by the energy generated in the firing step. Useful products such as cement and cast stone can be produced from the sintered product.

Kapolyi, L.

1984-03-13

219

Consumer's cognitive response-based creative product design process  

Microsoft Academic Search

The purpose of this paper is to present a creative product design process (PDP) based on customer's cognitive response (CCR) to product sign. Based on the user-product interaction model, combining with symbolic information-processing (SIP) and situativity (SIT) approaches, our work explored the process and methods of CCR, and then outlined the creative product design process model after analyzing the Gero's

Zhi-jun Wu; Liang-zhi Li; Chen Yu; Cai Yan

2010-01-01

220

Durability of Carbon Fiber Reinforced Cement.  

National Technical Information Service (NTIS)

Adverse environmental effects can decrease the useful life of cement and concrete products, and increase maintenance costs significantly. This report examines one method for enhancing the durability of cementitious compounds under severe environmental con...

P. Soroushian M. Nagi

1987-01-01

221

Downhole cementing tool assembly  

SciTech Connect

A cementing apparatus for use in cementing a casing string in a well bore is described comprising: (a) a float collar incorporated in the casing string, the float collar including a passage extending therethrough; (b) a cementing plug having a cylindrical body including an axial passage extending therethrough, the cementing plug body further including closure means extending across the axial passage; (c) a wiper plug having a cylindrical body including wiper means extending about the wiper plug body for wiping the casing as the wiper plug is advanced through the casing; (d) cooperative interlocking means located on the float collar, the cementing plug and the wiper plug for locking the cementing plug and the wiper plug to the float collar in a nonrotatable position; and (e) wherein the cementing plug and the wiper plug including frangible internal cutters embedded in the cementing plug and the wiper plug.

Wardlaw, L.J.; Young, J.A.

1987-12-08

222

ULTRA-LIGHTWEIGHT CEMENT  

SciTech Connect

The objective of this project is to develop an improved ultra- lightweight cement using ultra-lightweight hollow glass spheres (ULHS). This report discusses testing that was performed for analyzing the alkali-silica reactivity of ULHS in cement slurries.

Fred Sabins

2003-10-31

223

Modeling process-switching decisions under product life cycle uncertainty  

Microsoft Academic Search

We address the process-switching decision of a firm that adopts a mixed process strategy with respect to a new product in the context of product life cycle uncertainty. A mixed process strategy uses a flexible process in the early stages of the product's life cycle and later switches to a dedicated process to gain cost economies. We present a model

Ranga Ramasesh; Devanath Tirupati; Constantin A. Vaitsos

2010-01-01

224

How to Make Mulligan Stew: Process and Product Again.  

ERIC Educational Resources Information Center

Argues that, like making stew, there is more than one sequential writing process, and that while one cannot discern the process by examining the product, the product (or purpose) cannot help but shape the processes. (HTH)

Gorrell, Robert M.

1983-01-01

225

Production Process for Advanced Space Satellite System Cables/Interconnects.  

National Technical Information Service (NTIS)

This production process was generated for the satellite system program cables/interconnects group, which in essences had no well defined production process. The driver for the development of a formalized process was based on the set backs, problem areas, ...

L. Mendoza

2007-01-01

226

Do cement nanotubes exist?  

PubMed

Using atomistic simulations, this work indicates that cement nanotubes can exist. The chemically compatible nanotubes are constructed from the two main minerals in ordinary Portland cement pastes, namely calcium hydroxide and a calcium silicate hydrate called tobermorite. These results show that such nanotubes are stable and have outstanding mechanical properties, unique characteristics that make them ideally suitable for nanoscale reinforcements of cements. PMID:22589176

Manzano, H; Enyashin, A N; Dolado, J S; Ayuela, A; Frenzel, J; Seifert, G

2012-06-26

227

Molecular dynamics modeling of the effects of cementation on the acoustical properties of granular sedimentary rocks  

Microsoft Academic Search

The incidence of cementation processes on the acoustical properties of sands is studied via molecular dynamics simulation techniques. In our simulations, we consider samples with different degrees of compaction and cementing materials with distinct elastic properties. The microstructure of cemented sands is taken into account while adding cement at specific locations within the pores, such as grain-to-grain contacts. Results show

Xavier Garcia; Ernesto Medina

2006-01-01

228

Advanced Multi-Product Coal Utilization By-Product Processing Plant  

SciTech Connect

The objective of the project is to build a multi-product ash beneficiation plant at Kentucky Utilities 2,200-MW Ghent Generating Station, located in Carroll County, Kentucky. This part of the study includes an investigation of the secondary classification characteristics of the ash feedstock excavated from the lower ash pond at Ghent Station. The secondary classification testing was concluded using a continuous demonstration-scale lamella classifier that was operated at a feed rate of 0.3 to 1.5 tons/hr. Feed to the secondary classifier was generated by operating the primary classifier at the conditions shown to be effective previously. Samples were taken while the secondary classifier was operated under a variety of conditions in order to determine the range of conditions where the unit could be efficiently operated. Secondary classification was effective for producing an ultra-fine ash (UFA) product. Inclined lamella plates provided an effective settling surface for coarser ash particles and plate spacing was shown to be an important variable. Results showed that the closer the plate spacing, the finer the size distribution of the UFA product. Flotation of the secondary classifier feed provided a lower LOI UFA product (2.5% LOI vs. 4.5% LOI) and a dispersant dosage of 2 to 2.5 g/kg was adequate to provide UFA grade (3.8 to 4.4 {micro}m) and recovery (53 to 68% 5{micro}m recovery). The UFA yield without flotation was {approx}33% and lower ({approx}20%) with flotation. Demonstration plant product evaluations showed that water requirements in mortar were reduced and 100% of control strength was achieved in 28 days for the coarser products followed by further strength gain of up to 130% in 56 days. The highest strengths of 110% of control in 7 days and 140% in 56 days were achieved with the finer products. Mortar air requirements for processed products were essentially the same as those for standard mortar, suggesting that the unburned carbon remaining does not have an affinity for air entraining admixture (AEA), a consideration that is a significant benefit. In concrete, substitution of 20% showed that the UFA product outperformed a typical ash by achieving 105 to 107% of control strength after 28 days and 109.5 to 112% after 56 days. Higher substitution levels were shown to delay early strength development, but surpass control strength after 28 days while lower substitution levels provide both early and longer term strength. One of the most significant benefits provided by using UFA in concrete mix designs is the improved resistance to chloride permeability while some improvements is flexural strength were realized and tensile strength was essentially unchanged. Potentially significant benefits may also be offered by using UFA as a process addition in the manufacture of cement clinker.

John Groppo; Thomas Robl; Robert Rathbone

2006-06-01

229

Soy protein products: processing and use.  

PubMed

Soy protein products are mainly used as ingredients in formulated foods and seldom are seen by the public. They consist of four broad categories. (1) Most soy proteins are derived from "white flakes," made by dehulling, flaking and defatting soybeans by hexane extraction. These may then be milled into defatted flours or grits containing approximately 50-54% protein; extracted with ethanol or acidic waters to remove flavor compounds and flatulence sugars, producing soy protein concentrates containing 65-70% protein; or processed into soy protein isolates containing 90+% protein by alkali extraction of the protein, removal of fiber by centrifugation and reprecipitation and drying of the protein. (2) Full-fat products are made in enzyme-active and in toasted forms. (3) Various dried soyfoods, including soy milk and tofu, are produced. (4) Mixtures of soy proteins with cereals, dried milk or egg fractions, gelatin, stabilizers and emulsifiers are offered for specific baking, whipping, breading and batter applications. Texturized products, resembling meat chunks or bacon chips, are made by extrusion of flours and concentrates or spinning of isolates. Soy protein ingredients are used in compounded foods for their functional properties, including water and fat absorption, emulsification, aeration (whipping) and heat setting and for increasing total protein content and improving the essential amino acids profile. PMID:7884536

Lusas, E W; Riaz, M N

1995-03-01

230

Quartz cement in sandstones: a review  

NASA Astrophysics Data System (ADS)

Quartz cement as syntaxial overgrowths is one of the two most abundant cements in sandstones. The main factors that control the amount of quartz cement in sandstones are: framework composition; residence time in the "silica mobility window"; and fluid composition, flow volume and pathways. Thus, the type of sedimentary basin in which a sand was deposited strongly controls the cementation process. Sandstones of rift basins (arkoses) and collision-margin basins (litharenites) generally have only a few percent quartz cement; quartzarenites and other quartzose sandstones of intracratonic, foreland and passive-margin basins have the most quartz cement. Clay and other mineral coatings on detrital quartz grains and entrapment of hydrocarbons in pores retard or prevent cementation by quartz, whereas extremely permeable sands that serve as major fluid conduits tend to sequester the greatest amounts of quartz cement. In rapidly subsiding basins, like the Gulf Coast and North Sea basins, most quartz cement is precipitated by cooling, ascending formation water at burial depths of several kilometers where temperatures range from 60° to 100° C. Cementation proceeds over millions of years, often under changing fluid compositions and temperatures. Sandstones with more than 10% imported quartz cement pose special problems of fluid flux and silica transport. If silica is transported entirely as H 4SiO 4, convective recycling of formation water seems to be essential to explain the volume of cement present in most sandstones. Precipitation from single-cycle, upward-migrating formation water is adequate to provide the volume of cement only if significant volumes of silica are transported in unidentified complexes. Modeling suggests that quartz cementation of sandstones in intracratonic basins is effected by advecting meteoric water, although independent petrographic, isotopic or fluid inclusion data are lacking. Silica for quartz cement comes from both shale and sandstone beds within the depositional basin, including possibly deeply buried rocks undergoing low-grade metamorphism, but the relative importance of potential sources remains controversial and likely differs for different formations. The most likely important silica sources within unmetamorphosed shales include clay transformation (chiefly illitization of smectite), dissolution/pressure solution of detrital grains, and dissolution of opal skeletal grains; the most likely important sources of silica within unmetamorphosed sandstones include pressure solution of detrital quartz grains at grain contacts and at stylolites, feldspar alteration/dissolution, and perhaps carbonate replacement of silicate minerals and the margins of some quartz grains. Silica released by pressure solution in many sandstones post-dates the episode of cementation by quartz; thus, this silica must migrate and cement shallower sandstones in the basin or escape altogether. Some quartz-cemented sandstones are separated vertically from potential silica source beds by a kilometer or more, requiring silica transport over long distances. The similarity of diagenetic sequences in sandstones of different composition and ages apparently is the result of the normal temperature and time-dependent maturation of sediments, organic matter and pore fluids during burial in sedimentary basins. Silica that forms overgrowths is released by one or more diagenetic processes that apparently are controlled by temperature and time. Most cementation by quartz takes place when sandstone beds were in the silica mobility window specific to a particular sedimentary basin. Important secondary controls are introduced by compartmentalized domains produced by faults (e.g., North Sea) or overpressure boundaries (e.g., Gulf Coast Tertiary). Shallow meteoric water precipitates only small amounts of silica cement (generally less than 5% in most fluvial and colian sandstones), except in certain soils and at water tables in high-flux sand aquifers. Soil silcretes are chiefly cemented by opal and microcrystalline quartz, whereas water-tab

McBride, Earle F.

231

China: Emissions pattern of the world leader in CO2 emissions from fossil fuel consumption and cement production  

NASA Astrophysics Data System (ADS)

Release of carbon dioxide (CO2) from fossil fuel combustion and cement manufacture is the primary anthropogenic driver of climate change. Our best estimate is that China became the largest national source of CO2 emissions during 2006. Previously, the United States (US) had occupied that position. However, the annual emission rate in the US has remained relatively stable between 2001-2006 while the emission rate in China has more than doubled, apparently eclipsing that of the US in late 2006. Here we present the seasonal and spatial pattern of CO2 emissions in China, as well as the sectoral breakdown of emissions. Though our best point estimate places China in the lead position in terms of CO2 emissions, we qualify this statement in a discussion of the uncertainty in the underlying data (3-5% for the US; 15-20% for China). Finally, we comment briefly on the implications of China's new position with respect to international agreements to mitigate climate change.

Gregg, Jay S.; Andres, Robert J.; Marland, Gregg

2008-04-01

232

Studies on cement and mortar containing low-calcium fly ash, limestone, and dolomitic limestone  

Microsoft Academic Search

The effects of low-calcium fly ash (FA), limestone (LS), and dolomitic limestone (DLS) on the properties of cement and mortar has been investigated through a number of tests. Composition of cement hydration products in cement paste and mortar were made with clinker (PC), gypsum (G), FA, LS and DLS. The binders employed were Portland cement (OPC), fly ash–portland cement (FA–OPC),

Bülent Y?lmaz; Asim Olgun

2008-01-01

233

Comparative assessment of TRU waste forms and processes. Volume I. Waste form and process evaluations  

SciTech Connect

This study provides an assesses seven waste forms and eight processes for immobilizing transuranic (TRU) wastes. The waste forms considered are cast cement, cold-pressed cement, FUETAP (formed under elevated temperature and pressure) cement, borosilicate glass, aluminosilicate glass, basalt glass-ceramic, and cold-pressed and sintered silicate ceramic. The waste-immobilization processes considered are in-can glass melting, joule-heated glass melting, glass marble forming, cement casting, cement cold-pressing, FUETAP cement processing, ceramic cold-pressing and sintering, basalt glass-ceramic processing. Properties considered included gas generation, chemical durability, mechanical strength, thermal stability, and radiation stability. The ceramic products demonstrated the best properties, except for plutonium release during leaching. The glass and ceramic products had similar properties. The cement products generally had poorer properties than the other forms, except for plutonium release during leaching. Calculations of the Pu release indicated that the waste forms met the proposed NRC release rate limit of 1 part in 10/sup 5/ per year in most test conditions. The cast-cement process had the lowest processing cost, followed closely by the cold-pressed and FUETAP cement processes. Joule-heated glass melting had the lower cost of the glass processes. In-can melting in a high-quality canister had the highest cost, and cold-pressed and sintered ceramic the second highest. Labor and canister costs for in-can melting were identified. The major contributor to costs of disposing of TRU wastes in a defense waste repository is waste processing costs. Repository costs could become the dominant cost for disposing of TRU wastes in a commercial repository. It is recommended that cast and FUETAP cement and borosilicate glass waste-form systems be considered. 13 figures, 16 tables.

Ross, W.A.; Lokken, R.O.; May, R.P.; Roberts, F.P.; Timmerman, C.L.; Treat, R.L.; Westsik, J.H. Jr.

1982-09-01

234

Literature survey on cements for remediation of deformed casing in geothermal wells  

SciTech Connect

Brookhaven National Laboratory was requested to conduct a literature survey for the best available cement to use in the proposed casing patch as part of the Geothermal Drilling Organization (GDO) project on remediation of deformed casings. A total of 50 wells have been identified with deformed production casing in Unocal`s portion of The Geysers geothermal field. A procedure to address the casing deformation and avoid abandonment of these wells has been developed as described in the Geysers Deformed Casing Remediation Proposal. The proposed remediation procedure involves isolation of the zone of interest with an inflatable packer, milling the deformed casing and cementing a 7 inch diameter liner to extend approximately 100 ft above and 100 ft below the milled zone. During the milling operation it is possible that the original cement and surrounding formation may slough away. In order to specify a suitable cement formulation for the casing patch it is first necessary to identify and understand the deformation mechanism/s operating in The Geysers field. Subsequently, the required cement mechanical properties to withstand further deformation of the repaired system must be defined. From this information it can be determined whether available cement formulations meet these requirements. In addition to The Geysers, other geothermal fields are at possible risk of casing deformation due to subsidence, seismic activity, lateral and vertical formation movement or other processes. Therefore, the proposed remediation procedure may have applications in other fields.

Allan, M.L.; Philippacopoulos, A.J.

1998-12-31

235

Steel product cost estimation based on product features & process chain  

Microsoft Academic Search

The objective is to propose a cost estimating method which is fitted to recent continuously producing industrial context evolution. In order to quote the steel product price and control cost before production, estimating steel product cost accurately is important for steel enterprise. After analyzing the existing cost estimation methods, steel product cost estimation was given based on steel product features

Liu Xiao-bing; Cui Fa-jing; Meng Qiu-nan; Li Hao

2008-01-01

236

Production process for glass sand from the quartz waste from the beneficiation of kingiseppsk phosphorites  

SciTech Connect

This paper presents a process developed for the production of molding sand from the quartz waste which makes it possible to simplify the system for obtaining glass sand. According to this system, the main operation in the removal of most of the residual phosphate shell and alkaline earth metal oxides from the quartz waste is foam separation, using the residual concentration of reagents in the pulp (tallow and kerosene). After the subsequent washing and hydraulic classification, the sands meet the requirements set for molding sands grade Ob2K. The characteristics of the original flotation tailings and molding sand are presented. The mineralogical analysis of the molding sand showed that the iron-containing impurities are grains of glauconite, films of iron oxide on the surface of the grains, grains of ferrous-dolomite cement, and iron from the apparatus.

Ershov, V.I.; Lezhnev, Y.P.; Novofastovskaya, E.M.; Rants, G.F.; Shalamova, V.G.; Sinyakova, E.I.; Sokolova, E.I.

1985-12-01

237

ULTRA-LIGHTWEIGHT CEMENT  

SciTech Connect

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, comparison studies of the three cement systems examined several properties: tensile strength, Young's modulus, and shear bond. Testing to determine the effect of temperature cycling on the shear bond properties of the cement systems was also conducted. In addition, the stress-strain behavior of the cement types was studied. This report discusses a software program that is being developed to help design ULHS cements and foamed cements.

Fred Sabins

2002-04-29

238

ULTRA-LIGHTWEIGHT CEMENT  

SciTech Connect

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 will be performed for analyzing the alkali-silica reactivity of ULHS in cement slurries, as well as the results of Field Tests 1 and 2.

Fred Sabins

2002-10-31

239

Measuring the eco-efficiency of cement use  

Microsoft Academic Search

At present, the cement industry generates approximately 5% of the world’s anthropogenic CO2 emissions. This share is expected to increase since demand for cement based products is forecast to multiply by a factor of 2.5 within the next 40years and the traditional strategies to mitigate emissions, focused on the production of cement, will not be capable of compensating such growth.

Bruno L. Damineli; Fernanda M. Kemeid; Patricia S. Aguiar; Vanderley M. John

2010-01-01

240

Process, optimized acidizing reduce production facility upsets  

SciTech Connect

The filtration/absorption process, coupled with optimum treatments, prevent facility upsets that increase the time and resources required for bringing a well back on-line following an acid stimulation. Surface active agents, required in acidizing to improve well productivity, can form oil/water emulsions and cause unacceptable oil and grease levels during acid flowback. But recent offshore experiences after acidizing show that operators can achieve oil and grease discharge limits without facility upsets. To minimize oil and grease, the additives need to be optimized by adding a mutual breakout solvent (MBS). MBS has the dual function of being a mutual solvent and a sludge and emulsion control additive. The paper discusses acidizing problems, acid additives, handling options, and a case history of the Main Pass A field.

Ali, S.A. [Chevron U.S.A. Production Co., New Orleans, LA (United States); Hill, D.G. [Schlumberger Dowell, Tulsa, OK (United States); McConnell, S.B. [Schlumberger Dowell, Houston, TX (United States); Johnson, M.R. [Gulf States Environmental Solutions Inc., Houston, TX (United States)

1997-02-10

241

Phosphate-bonded calcium aluminate cements  

DOEpatents

A method is described for making a rapid-setting phosphate-bonded cementitious material. A powdered aluminous cement is mixed with an aqueous solution of ammonium phosphate. The mixture is allowed to set to form an amorphous cementitious material which also may be hydrothermally treated at a temperature of from about 120 C to about 300 C to form a crystal-containing phosphate-bonded material. Also described are the cementitious products of this method and the cement composition which includes aluminous cement and ammonium polyphosphate. 10 figures.

Sugama, T.

1993-09-21

242

Phosphate-bonded calcium aluminate cements  

DOEpatents

A method is described for making a rapid-setting phosphate-bonded cementitious material. A powdered aluminous cement is mixed with an aqueous solution of ammonium phosphate. The mixture is allowed to set to form an amorphous cementitious material which also may be hydrothermally treated at a temperature of from about 120.degree. C. to about 300.degree. C. to form a crystal-containing phosphate-bonded material. Also described are the cementitious products of this method and the cement composition which includes aluminous cement and ammonium polyphosphate.

Sugama, Toshifumi (Mastic Beach, NY) [Mastic Beach, NY

1993-01-01

243

Atmospheric Processing Module for Mars Propellant Production  

NASA Technical Reports Server (NTRS)

The multi-NASA center Mars Atmosphere and Regolith COllector/PrOcessor for Lander Operations (MARCO POLO) project was established to build and demonstrate a methane/oxygen propellant production system in a Mars analog environment. Work at the Kennedy Space Center (KSC) Applied Chemistry Laboratory is focused on the Atmospheric Processing Module (APM). The purpose of the APM is to freeze carbon dioxide from a simulated Martian atmosphere containing the minor components nitrogen, argon, carbon monoxide, and water vapor at Martian pressures (approx.8 torr) by using dual cryocoolers with alternating cycles of freezing and sublimation. The resulting pressurized CO2 is fed to a methanation subsystem where it is catalytically combined with hydrogen in a Sabatier reactor supplied by the Johnson Space Center (JSC) to make methane and water vapor. We first used a simplified once-through setup and later employed a HiCO2 recycling system to improve process efficiency. This presentation and paper will cover (1) the design and selection of major hardware items, such as the cryocoolers, pumps, tanks, chillers, and membrane separators, (2) the determination of the optimal cold head design and flow rates needed to meet the collection requirement of 88 g CO2/hr for 14 hr, (3) the testing of the CO2 freezer subsystem, and (4) the integration and testing of the two subsystems to verify the desired production rate of 31.7 g CH4/hr and 71.3 g H2O/hr along with verification of their purity. The resulting 2.22 kg of CH4/O2 propellant per 14 hr day (including O2 from electrolysis of water recovered from regolith, which also supplies the H2 for methanation) is of the scale needed for a Mars Sample Return mission. In addition, the significance of the project to NASA's new Mars exploration plans will be discussed.

Muscatello, Anthony; Gibson, Tracy; Captain, James; Athman, Robert; Nugent, Matthew; Parks, Steven; Devor, Robert

2013-01-01

244

Atmospheric Processing Module for Mars Propellant Production  

NASA Technical Reports Server (NTRS)

The multi-NASA center Mars Atmosphere and Regolith COllector/PrOcessor for Lander Operations (MARCO POLO) project was established to build and demonstrate a methane/oxygen propellant production system in a Mars analog environment. Work at the Kennedy Space Center (KSC) Applied Chemistry Laboratory is focused on the Atmospheric Processing Module (APM). The purpose of the APM is to freeze carbon dioxide from a simulated Martian atmosphere containing the minor components nitrogen, argon, carbon monoxide, and water vapor at Martian pressures (8 torr) by using dual cryocoolers with alternating cycles of freezing and sublimation. The resulting pressurized CO2 is fed to a methanation subsystem where it is catalytically combined with hydrogen in a Sabatier reactor supplied by the Johnson Space Center (JSC) to make methane and water vapor. We first used a simplified once-through setup and later employed a HiCO2 recycling system to improve process efficiency. This presentation and paper will cover (1) the design and selection of major hardware items, such as the cryocoolers, pumps, tanks, chillers, and membrane separators, (2) the determination of the optimal cold head design and flow rates needed to meet the collection requirement of 88 g CO2/hr for 14 hr, (3) the testing of the CO2 freezer subsystem, and (4) the integration and testing of the two subsystems to verify the desired production rate of 31.7 g CH4/hr and 71.3 g H20/hr along with verification of their purity. The resulting 2.22 kg of CH4/O2 propellant per 14 hr day (including O2 from electrolysis of water recovered from regolith, which also supplies the H2 for methanation) is of the scale needed for a Mars Sample Return mission. In addition, the significance of the project to NASA's new Mars exploration plans will be discussed.

Muscatello, Anthony; Gibson, Tracy; Captain, James; Athman, Robert; Nugent, Matthew; Parks, Steven; Devor, Robert

2013-01-01

245

Technology Transfer and the Product Development Process  

SciTech Connect

It is my pleasure this morning to address a topic that is much talked about in passing but rarely examined from a first person point of view. That topic is Technology Transfer. Over the next 30 minutes I'd like to approach Technology Transfer within the context of the Product Development Process looking at it from the perspectives of the federal government researcher and the industry manufacturer/user. Fist let us recognize that we are living in an ''Information Age'', where global economic and military competition is determined as much by technology as it is by natural resource assets. It is estimated that technical/scientific information is presently growing at a rate of l3 percent per year; this is expected to increase to 30 percent per year by the turn of the century. In fact, something like 90 percent of all scientific knowledge has been generated in the last 30 years; this pool will double again in the next 10-15 years (Exhibit 1). Of all the scientists and engineers throughout history, 90% live and work in the present time. Successfully managing this technical information/knowledge--i.e., transforming the results of R&D to practical applications--will be an important measure of national strength. A little over a dozen years ago, the United States with only 5 percent of the world's population was generating approximately 75 percent of the world's technology. The US. share is now 50 percent and may decline to 30 percent by the turn of the century. This decline won't be because of downturn in U.S. technological advances but because the other 95 percent of the world's population will be increasing its contribution. Economic and military strength then, will be determined by how quickly and successfully companies, industries, and nations can apply new technological information to practical applications--i.e., how they manage technology transfer within the context of the product development process. Much discussion and pronouncements are ongoing in public forums today over the apparent decline in global competitiveness of U.S. industry. The question is why does U.S. industry not succeed in the development and marketing of competitive products when they lead in the generation of new technology.

Mock, John E.

1989-03-21

246

The contemporary cement cycle of the United States  

USGS Publications Warehouse

A country-level stock and flow model for cement, an important construction material, was developed based on a material flow analysis framework. Using this model, the contemporary cement cycle of the United States was constructed by analyzing production, import, and export data for different stages of the cement cycle. The United States currently supplies approximately 80% of its cement consumption through domestic production and the rest is imported. The average annual net addition of in-use new cement stock over the period 2000-2004 was approximately 83 million metric tons and amounts to 2.3 tons per capita of concrete. Nonfuel carbon dioxide emissions (42 million metric tons per year) from the calcination phase of cement manufacture account for 62% of the total 68 million tons per year of cement production residues. The end-of-life cement discards are estimated to be 33 million metric tons per year, of which between 30% and 80% is recycled. A significant portion of the infrastructure in the United States is reaching the end of its useful life and will need to be replaced or rehabilitated; this could require far more cement than might be expected from economic forecasts of demand for cement. ?? 2009 Springer Japan.

Kapur, A.; Van Oss, H. G.; Keoleian, G.; Kesler, S. E.; Kendall, A.

2009-01-01

247

Effect of Mineral Trioxide Aggregate, Calcium-Enriched Mixture Cement and Mineral Trioxide Aggregate with Disodium Hydrogen Phosphate on BMP-2 Production.  

PubMed

Introduction: One of the hypotheses regarding the calcification induction by mineral trioxide aggregate (MTA) is the involvement of transforming growth factor-Beta (TGF-?) super family. Calcium-enriched mixture (CEM) cement is one of the endodontic biomaterials with clinical applications similar to MTA. The aim of the present in vitro study was to compare the induction of bone morphogenic protein-2 (BMP-2) by a combination of disodium hydrogen phosphate (DSHP) and tooth colored ProRoot MTA (WMTA), to that of CEM cement and WMTA. Methods and Materials: Human gingival fibroblasts (HGFs) were obtained from the attached gingiva of human premolars. HGFs were cultured in Dulbecco's Modified Eagle's medium, supplemented with 10% fetal calf serum, penicillin, and streptomycin. Cells in groups 1, 2 and 3 were exposed to WMTA, CEM and WMTA+DSHP discs, respectively. The fourth group served as the control. After 72 h of exposure, HGF viability was determined by Mosmann's tetrazolium toxicity (MTT) assay. BMP-2 levels in cell-free culture media were determined by enzyme-linked immunosorbent assay (ELISA). Statistical analysis was performed using the one-way ANOVA, followed by the post hoc Games-Howell test for BMP-2 and post hoc Tukey's test for the results of MTT assay. Results: Cellular viability was significantly higher in group 3 compared to the other groups (P<0.05); however, CEM and WMTA did not exhibit significant differences (P=0.08). The control group exhibited significantly higher cellular viability in comparison to the other groups of the study (P<0.05). The highest and lowest protein production rates were observed in the WMTA (3167±274.46 pg/mL) and WMTA+DSHP (1796±839.49 pg/mL) groups, respectively. There were no significant differences between the control, WMTA and CEM groups (P>0.05). Conclusion: WMTA and CEM did not exhibit any significant differences in terms of inducing BMP-2 production; however, incorporation of DSHP into WMTA resulted in a decrease in the induction of this protein. PMID:25031598

Ghasemi, Negin; Rahimi, Saeed; Lotfi, Mehrdad; Solaimanirad, Jafar; Shahi, Shahriar; Shafaie, Hajar; Salem Milani, Amin; Shakuie, Sahar; Zand, Vahid; Abdolrahimi, Majid

2014-01-01

248

Effect of Mineral Trioxide Aggregate, Calcium-Enriched Mixture Cement and Mineral Trioxide Aggregate with Disodium Hydrogen Phosphate on BMP-2 Production  

PubMed Central

Introduction: One of the hypotheses regarding the calcification induction by mineral trioxide aggregate (MTA) is the involvement of transforming growth factor-Beta (TGF-?) super family. Calcium-enriched mixture (CEM) cement is one of the endodontic biomaterials with clinical applications similar to MTA. The aim of the present in vitro study was to compare the induction of bone morphogenic protein-2 (BMP-2) by a combination of disodium hydrogen phosphate (DSHP) and tooth colored ProRoot MTA (WMTA), to that of CEM cement and WMTA. Methods and Materials: Human gingival fibroblasts (HGFs) were obtained from the attached gingiva of human premolars. HGFs were cultured in Dulbecco’s Modified Eagle’s medium, supplemented with 10% fetal calf serum, penicillin, and streptomycin. Cells in groups 1, 2 and 3 were exposed to WMTA, CEM and WMTA+DSHP discs, respectively. The fourth group served as the control. After 72 h of exposure, HGF viability was determined by Mosmann’s tetrazolium toxicity (MTT) assay. BMP-2 levels in cell-free culture media were determined by enzyme-linked immunosorbent assay (ELISA). Statistical analysis was performed using the one-way ANOVA, followed by the post hoc Games-Howell test for BMP-2 and post hoc Tukey’s test for the results of MTT assay. Results: Cellular viability was significantly higher in group 3 compared to the other groups (P<0.05); however, CEM and WMTA did not exhibit significant differences (P=0.08). The control group exhibited significantly higher cellular viability in comparison to the other groups of the study (P<0.05). The highest and lowest protein production rates were observed in the WMTA (3167±274.46 pg/mL) and WMTA+DSHP (1796±839.49 pg/mL) groups, respectively. There were no significant differences between the control, WMTA and CEM groups (P>0.05). Conclusion: WMTA and CEM did not exhibit any significant differences in terms of inducing BMP-2 production; however, incorporation of DSHP into WMTA resulted in a decrease in the induction of this protein.

Ghasemi, Negin; Rahimi, Saeed; Lotfi, Mehrdad; Solaimanirad, Jafar; Shahi, Shahriar; Shafaie, Hajar; Salem Milani, Amin; Shakuie, Sahar; Zand, Vahid; Abdolrahimi, Majid

2014-01-01

249

Process-based structuring knowledge in product development  

Microsoft Academic Search

Efficient knowledge management is a key success factor for product development. A basic idea behind knowledge management is to construct a global architecture of knowledge. Product development process modeling can help knowledge engineers structure knowledge. A so-called ¿state-process-resource¿ model in the product development domain is proposed. The results of a product at the intermediate-stages are called product states. Process elements,

Qian-Wang Deng; Li-Ping Yang; Xin-Wei Wang

2009-01-01

250

40 CFR 158.330 - Description of production process.  

Code of Federal Regulations, 2013 CFR

...Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS DATA REQUIREMENTS FOR PESTICIDES Product Chemistry § 158.330 Description of production process. If the product is produced by an integrated system, the...

2013-07-01

251

40 CFR 161.162 - Description of production process.  

Code of Federal Regulations, 2013 CFR

...PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS DATA REQUIREMENTS FOR REGISTRATION OF ANTIMICROBIAL PESTICIDES Product Chemistry Data Requirements § 161.162 Description of production process. If the product is produced by an integrated...

2013-07-01

252

Dentin-cement Interfacial Interaction  

PubMed Central

The interfacial properties of a new calcium-silicate-based coronal restorative material (Biodentine™) and a glass-ionomer cement (GIC) with dentin have been studied by confocal laser scanning microscopy (CLSM), scanning electron microscopy (SEM), micro-Raman spectroscopy, and two-photon auto-fluorescence and second-harmonic-generation (SHG) imaging. Results indicate the formation of tag-like structures alongside an interfacial layer called the “mineral infiltration zone”, where the alkaline caustic effect of the calcium silicate cement’s hydration products degrades the collagenous component of the interfacial dentin. This degradation leads to the formation of a porous structure which facilitates the permeation of high concentrations of Ca2+, OH-, and CO32- ions, leading to increased mineralization in this region. Comparison of the dentin-restorative interfaces shows that there is a dentin-mineral infiltration with the Biodentine, whereas polyacrylic and tartaric acids and their salts characterize the penetration of the GIC. A new type of interfacial interaction, “the mineral infiltration zone”, is suggested for these calcium-silicate-based cements.

Atmeh, A.R.; Chong, E.Z.; Richard, G.; Festy, F.; Watson, T.F.

2012-01-01

253

ULTRA-LIGHTWEIGHT CEMENT  

SciTech Connect

The objective of this project is to develop an improved ultra-lightweigh cement using ultralight hollow glass spheres (ULHS). Work reported herein addresses Task 1: Assess Ultra-Lightweight Cementing Problems, Task 2: Review Russian Ultra-Lightweight Cement Literature, and Task 3: Test Ultra-Lightweight Cements. Results reported this quarter include a review and summary surface pipe and intermediate casing cementing conditions historically encountered in the US and establishment of average design conditions for ULHS cements. Russian literature concerning development and use of ultra-lightweight cements employing either nitrogen or ULHS was reviewed, and a summary is presented. Quality control testing of materials used to formulate ULHS cements in the laboratory was conducted to establish baseline material performance standards. A testing protocol was developed employing standard procedures as well as procedures tailored to evaluate ULHS. This protocol is presented and discussed. finally, results of initial testing of ULHS cements is presented along with analysis to establish cement performance design criteria to be used during the remainder of the project.

Fred Sabins

2001-01-15

254

Rice Husk Ash as a Supplementary Raw Material for the Production of Cellulose–Cement Composites with Improved Performance  

Microsoft Academic Search

Rice husk is an agricultural by-product worldwide in large quantities available. This is a suitable biomass source for energy\\u000a production. Compared to other agricultural by-products, the burned rice husk presents a high yield of ash (about 20%) mainly\\u000a composed of silica that will be mostly amorphous when properly incinerated. Extensive research in the past three decades has\\u000a allowed the introduction

Conrado de Souza Rodrigues; Khosrow Ghavami; Piet Stroeven

2010-01-01

255

Fuel Production from Coal by the Mobil Oil Process Using Nuclear High-Temperature Process Heat.  

National Technical Information Service (NTIS)

Two processes for the production of liquid hydrocarbons are presented: Direct conversion of coal into fuel (coal hydrogenation) and indirect conversion of coal into fuel (syngas production, methanol synthesis, Mobil Oil process). Both processes have sever...

G. Hoffmann

1982-01-01

256

Cementation and Neomorphism: Incorporating the Basics of Diagenesis into Any Sedimentary Geology Course  

NSDL National Science Digital Library

Two or three weeks of the course are dedicated to studying diagenesis. Lectures start with a general definition of diagenesis, the range of conditions under which it occurs, and examples of diverse diagenetic environments and features. I use rice crispy cereal and rice crispy treats to introduce cement (the marshmellow is the cement that "glues" the rice krispies together). I also incorporate basic hydrogeology to show how pores filled with (or partially filled with) groundwater provide both the space and the material for cementation. As part of this lecture, I show the students various rock samples and photomicrographs in which they can see cement examples. I outline the different cement minerals and shapes and how they can be used to interpret past diagenetic conditions (eg., gravitational "pendant" calcite cements indicate that the host sediment was once in a vadose zone with groundwater rich in calcium and carbonate). I also discuss types of pores during these lectures and the ways that pores form. We also discuss criteria for recognizing cements. After two one-hour lectures about cements, we have a lab exercise in which the students are given ~10 samples (including hand samples and thin sections) and asked to sketch and describe the cement types. The next one-hour lecture focuses on neomorphic processes and their products, including replacement, recrystallization, and polymorphic transition. As part of the lecture, we look at photomicrographs and hand samples that illstrate various neomorphic features, such as replacement dolomite and replacement chert. We establish criteria for distinguishing cements from neomorphic fabrics. This lecture is followed by a lab exercise that presents the students with ~10 rocks and thin sections and asks them to sketch and identify neomorphic fabrics. This lab is follwed by another one-hour lecture on compaction features, dissolution evidence, and determining paragentic sequences. If I am short on time, that is all I do for diagenesis. However, ideally, I continue with a lecture focused on the "dolomite problem" and some case studies of other types of diagenesis, as well as a third lab assignment that combines cementation, neomorphism, compaction, dissolution, and paragenetic sequences. As part of this section, I also try to incorporate examples of methods other than petrology (eg., fluid inclusion studies, stable isotope studies, dating) that are used for diagenetic studies. Later in the course, we take several field trips in which the students examine diagenetic features.

Benison, Kathy

257

Immobilization of radioactive waste by cementation with purified kaolin clay.  

PubMed

A study is undertaken to determine the waste immobilization performance of low-level wastes in cement-clay mixtures. Liquid low-level wastes are precipitated using chemical methods, followed by solidification in drums. Solidification is done using cementation processes. Long-term leaching rates of the radionuclides are used as indicators of immobilization performance of solidified waste forms. In addition to evaluating the effects of kaolin clay on the leaching properties of the cemented waste forms, the effect of addition of kaolin on the strength of the cemented waste form is also investigated. The long term leaching tests show that inclusion of kaolin in cement reduces the leaching rates of the radionuclides significantly. However, clay additions in excess of 15 wt.% causes a significant decrease in the hydrolytic stability of cemented waste form. It is found that the best waste isolation, without causing a loss in the mechanical strength, is obtained when the kaolin content in cement is 5%. PMID:12092756

Osmanlioglu, A Erdal

2002-01-01

258

Integrated Product and Process Data for B2B Collaboration  

SciTech Connect

Collaborative development of engineered products in a business-to-business (B2B) environment will require more than just the selection of components from an on-line catalogue. It will involve the electronic exchange of product, process, and production engineering information during both design and manufacturing. While the state-of-the-practice does include a variety of ways to exchange product data electronically, it does not extend to the exchange of manufacturing process data. The reason is simple; process data is usually tied to specific manufacturing resources. These resources are not known typically at product development time. This paper proposes an approach, called an Integrated Product and Process Data (IPPD), where manufacturing process data is considered during product development. This approach replaces traditional process plans, which are resource specific, with a resource-independent process representation. Such a representation will allow a much wider collaboration among business partners and provide the necessary base for collaborative product development.

Kulvatunyou, Boonserm [ORNL; Ivezic, Nenad [ORNL; Jones, Albert [National Institute of Standards and Technology (NIST); Wysk, Richard A. [Pennsylvania State University

2003-09-01

259

PRODUCTION OF CARBON PRODUCTS USING A COAL EXTRACTION PROCESS  

SciTech Connect

The purpose of this DOE-funded effort is to develop technologies for carbon products from coal-derived feed-stocks. Carbon products can include precursor materials such as solvent extracted carbon ore (SECO) and synthetic pitch (Synpitch). In addition, derived products include carbon composites, fibers, foams and others.

Dady Dadyburjor; Chong Chen; Elliot B. Kennel; Liviu Magean; Peter G. Stansberry; Alfred H. Stiller; John W. Zondlo

2005-12-12

260

Crushed cement concrete substitution for construction aggregates; a materials flow analysis  

USGS Publications Warehouse

An analysis of the substitution of crushed cement concrete for natural construction aggregates is performed by using a materials flow diagram that tracks all material flows into and out of the cement concrete portion of the products made with cement concrete: highways, roads, and buildings. Crushed cement concrete is only one of the materials flowing into these products, and the amount of crushed cement concrete substituted influences the amount of other materials in the flow. Factors such as availability and transportation costs, as well as physical properties, that can affect stability and finishability, influence whether crushed cement concrete or construction aggregates should be used or predominate for a particular end use.

Kelly, Thomas

1998-01-01

261

Downhole cementing tool assembly  

SciTech Connect

This patent describes a cementing apparatus for use in cementing a casing string in a well bore. It comprises a float collar incorporated in the casing string, the float collar including a passage extending therethrough; a cementing plug having a cylindrical body including an axial passage extending therethrough, the cementing plug body further including closure means extending across the axial passage; a wiper plug having a cylindrical body including wiper means extending about the wiper plug body for wiping the casing as the wiper plug is advanced through the casing; and cooperative interlocking means located on the float collar, the cementing plug and the wiper plug for locking the cementing plug and the wiper plug to the float collar in a nonrotatable position.

Wardlaw, L.J.; Young, J.A.

1991-08-06

262

Reducing CO2-Emission by using Eco-Cements  

NASA Astrophysics Data System (ADS)

CO2 concentration in the air is rising constantly. Globally, cement companies are emitting nearly two billion tonnes/year of CO2 (or around 6 to 7 % of the planet's total CO2 emissions) by producing portland cement clinker. At this pace, by 2025 the cement industry will be emitting CO2 at a rate of 3.5 billion tones/year causing enormous environmental damage (Shi et al., 2011; Janotka et al., 2012). At the dawn of the industrial revolution in the mid-eighteenth century the concentration of CO2 was at a level of ca. 280 ppm. 200 years later at the time of World War II the CO2 level had risen to 310 ppm what results in a rate of increase of 0,15 ppm per year for that period (Shi et al., 2011). In November 2011 the CO2 concentration reached a value of 391 ppm (NOAA Earth System Research Laboratory, 2011), a rise of ca. 81 ppm in 66 years and an increased rate of around 1,2 ppm/year respectively. In the same period cement production in tons of cement has multiplied by a factor of ca. 62 (Kelly & Oss, US Geological Survey, 2010). Thus new CO2-saving eco-cement types are gaining in importance. In these cement types the energy-consuming portland cement clinker is partially replaced by latent hydraulic additives such as blast furnace slag, fly ash or zeolite. These hydraulic additives do not need to be fired in the rotary furnace. They ony need to be pulverized to the required grain size and added to the ground portland cement clinker. Hence energy is saved by skipping the engery-consuming firing process, in addition there is no CO2-degassing as there is in the case of lime burning. Therefore a research project between Austria and Slovakia, funded by the EU (Project ENVIZEO), was initiated in 2010. The main goal of this project is to develop new CEM V eco-types of cements and certificate them for common usage. CEM V is a portland clinker saving cement kind that allows the reduction of clinker to a proportion of 40-64% for CEM V/A and 20-39% for CEM V/B respectively by the input of slag sands, puzzolanes and fly ash (according to standard EN 197-1). In this context four new CEM V kinds have been created, two Austrian types based on slag and fly ash, and two Slovak types, one based on slag and fly ash, the other on slag and natural pozzolana. The pozzolana consist of zeolite of clinoptilolite type that is gained from a Slovak deposit.

Voit, K.; Bergmeister, K.; Janotka, I.

2012-04-01

263

Aluminum-rich belite sulfoaluminate cements: Clinkering and early age hydration  

SciTech Connect

Belite sulfoaluminate (BSA) cements have been proposed as environmentally friendly building materials, as their production may release up to 35% less CO{sub 2} into the atmosphere when compared to ordinary Portland cements. Here, we discuss the laboratory production of three aluminum-rich BSA clinkers with nominal mineralogical compositions in the range C{sub 2}S (50-60%), C{sub 4}A{sub 3}$ (20-30%), CA (10%) and C{sub 12}A{sub 7} (10%). Using thermogravimetry, differential thermal analysis, high temperature microscopy, and X-ray powder diffraction with Rietveld quantitative phase analysis, we found that burning for 15 min at 1350 deg. C was the optimal procedure, in these experimental conditions, for obtaining the highest amount of C{sub 4}A{sub 3}$, i.e. a value as close as possible to the nominal composition. Under these experimental conditions, three different BSA clinkers, nominally with 20, 30 and 30 wt.% of C{sub 4}A{sub 3}$, had 19.6, 27.1 and 27.7 wt.%, C{sub 4}A{sub 3}$ respectively, as determined by Rietveld analysis. We also studied the complex hydration process of BSA cements prepared by mixing BSA clinkers and gypsum. We present a methodology to establish the phase assemblage evolution of BSA cement pastes with time, including amorphous phases and free water. The methodology is based on Rietveld quantitative phase analysis of synchrotron and laboratory X-ray powder diffraction data coupled with chemical constraints. A parallel calorimetric study is also reported. It is shown that the beta-C{sub 2}S phase is more reactive in aluminum-rich BSA cements than in standard belite cements. On the other hand, C{sub 4}A{sub 3}$ reacts faster than the belite phases. The gypsum ratio in the cement is also shown to be an important factor in the phase evolution.

Martin-Sedeno, M. Carmen; Cuberos, Antonio J.M.; De la Torre, Angeles G.; Alvarez-Pinazo, Gema [Departamento de Quimica Inorganica, Cristalografia y Mineralogia, Universidad de Malaga, 29071 Malaga (Spain); Ordonez, Luis M. [Unidad Tecnica de Investigacion de Materiales, AIDICO, Avda. Benjamin Franklin, 17 Paterna, Valencia (Spain); Gateshki, Milen [PANalytical, B.V. P.O. Box 13. 7600 AA Almelo (Netherlands); Aranda, Miguel A.G., E-mail: g_aranda@uma.e [Departamento de Quimica Inorganica, Cristalografia y Mineralogia, Universidad de Malaga, 29071 Malaga (Spain)

2010-03-15

264

CARBON DIOXIDE EMISSIONS FROM THE GLOBAL CEMENT INDUSTRY1  

Microsoft Academic Search

Abstract The cement industry contributes about 5% to global anthropogenic CO2 emissions, making the cement industry an important sector for CO2-emission mitigation strategies. CO2 is emitted from the calcination process of limestone, from combustion of fuels in the kiln, as well as from power generation. In this paper, we review the total CO2 emissions from cement making, including process and

Ernst Worrell; Lynn Price; Nathan Martin; Chris Hendriks; Leticia Ozawa Meida

2001-01-01

265

Bagasse-reinforced cement composites  

Microsoft Academic Search

Bagasse is abundantly available in many countries as a by-product from sugar mills and is being mostly used as fuel or disposed of by incineration. An attempt has been made to convert this byproduct into useful eco-friendly cement-bonded composites, which can be used for various internal and external applications in buildings. The investigations include optimization of parameters such as bagasse

L. K. Aggarwal

1995-01-01

266

ULTRA-LIGHTWEIGHT CEMENT  

SciTech Connect

The objective of this project is to develop an improved ultra-lightweight cement using ultra-lightweight hollow glass spheres (ULHS). This report discusses testing that was performed for analyzing the alkali-silica reactivity of ULHS in cement slurries. DOE joined the Materials Management Service (MMS)-sponsored joint industry project ''Long-Term Integrity of Deepwater Cement under Stress/Compaction Conditions.'' Results of the project contained in two progress reports are also presented in this report.

Fred Sabins

2003-01-31

267

Personal exposure to inhalable cement dust among construction workers  

NASA Astrophysics Data System (ADS)

A case study was carried out in 2006-2007 to assess the actual cement dust exposure among construction workers involved in a full-scale construction project and as a comparison among workers involved in various stages of cement and concrete production. Full-shift personal exposure measurements were performed for several job types. Inhalable dust and cement dust (based on analysis of elemental calcium) concentrations were determined. Inhalable dust exposures at the construction site ranged from 0.05 to 34 mg/m3, with a mean concentration of 1.0 mg/m3. For inhalable cement dust mean exposure was 0.3 mg/m3 (range 0.02-17 mg/m3). Reinforcement and pouring workers had the lowest average concentrations. Inhalable dust levels in the ready-mix and pre-cast concrete plants were, on average, below 0.5 mg/m3 for inhalable dust and below 0.2 mg/m3 for inhalable cement dust. Highest dust concentrations were measured in cement production, particularly during cleaning tasks (inhalable dust GM=55 mg/m3; inhalable cement dust GM=33 mg/m3) at which point the workers wore personal protective equipment. Elemental measurements showed highest but very variable cement percentages in the cement plant and very low percentages of cement during reinforcement work and pouring.

Peters, Susan; Thomassen, Yngvar; Fechter-Rink, Edeltraud; Kromhout, Hans

2009-02-01

268

Accelerated Biodegradation of Cement by Sulfur-Oxidizing Bacteria as a Bioassay for Evaluating Immobilization of Low-Level Radioactive Waste  

PubMed Central

Disposal of low-level radioactive waste by immobilization in cement is being evaluated worldwide. The stability of cement in the environment may be impaired by sulfur-oxidizing bacteria that corrode the cement by producing sulfuric acid. Since this process is so slow that it is not possible to perform studies of the degradation kinetics and to test cement mixtures with increased durability, procedures that accelerate the biodegradation are required. Semicontinuous cultures of Halothiobacillus neapolitanus and Thiomonas intermedia containing thiosulfate as the sole energy source were employed to accelerate the biodegradation of cement samples. This resulted in a weight loss of up to 16% after 39 days, compared with a weight loss of 0.8% in noninoculated controls. Scanning electron microscopy of the degraded cement samples revealed deep cracks, which could be associated with the formation of low-density corrosion products in the interior of the cement. Accelerated biodegradation was also evident from the leaching rates of Ca2+ and Si2+, the major constituents of the cement matrix, and Ca exhibited the highest rate (up to 20 times greater than the control rate) due to the reaction between free lime and the biogenic sulfuric acid. Leaching of Sr2+ and Cs+, which were added to the cement to simulate immobilization of the corresponding radioisotopes, was also monitored. In contrast to the linear leaching kinetics of calcium, silicon, and strontium, the leaching pattern of cesium produced a saturation curve similar to the control curve. Presumably, the leaching of cesium is governed by the diffusion process, whereas the leaching kinetics of the other three ions seems to governed by dissolution of the cement.

Aviam, Orli; Bar-Nes, Gabi; Zeiri, Yehuda; Sivan, Alex

2004-01-01

269

Accelerated biodegradation of cement by sulfur-oxidizing bacteria as a bioassay for evaluating immobilization of low-level radioactive waste.  

PubMed

Disposal of low-level radioactive waste by immobilization in cement is being evaluated worldwide. The stability of cement in the environment may be impaired by sulfur-oxidizing bacteria that corrode the cement by producing sulfuric acid. Since this process is so slow that it is not possible to perform studies of the degradation kinetics and to test cement mixtures with increased durability, procedures that accelerate the biodegradation are required. Semicontinuous cultures of Halothiobacillus neapolitanus and Thiomonas intermedia containing thiosulfate as the sole energy source were employed to accelerate the biodegradation of cement samples. This resulted in a weight loss of up to 16% after 39 days, compared with a weight loss of 0.8% in noninoculated controls. Scanning electron microscopy of the degraded cement samples revealed deep cracks, which could be associated with the formation of low-density corrosion products in the interior of the cement. Accelerated biodegradation was also evident from the leaching rates of Ca(2+) and Si(2+), the major constituents of the cement matrix, and Ca exhibited the highest rate (up to 20 times greater than the control rate) due to the reaction between free lime and the biogenic sulfuric acid. Leaching of Sr(2+) and Cs(+), which were added to the cement to simulate immobilization of the corresponding radioisotopes, was also monitored. In contrast to the linear leaching kinetics of calcium, silicon, and strontium, the leaching pattern of cesium produced a saturation curve similar to the control curve. Presumably, the leaching of cesium is governed by the diffusion process, whereas the leaching kinetics of the other three ions seems to governed by dissolution of the cement. PMID:15466547

Aviam, Orli; Bar-Nes, Gabi; Zeiri, Yehuda; Sivan, Alex

2004-10-01

270

Description of Latvian Metal Production and Processing Enterprises' Air Emissions  

NASA Astrophysics Data System (ADS)

The metal production and processing sector in Latvia has acquired a stable position in the national economy. Smelting of ferrous and nonferrous metals, production of metalware, galvanisation, etc. are developed in Latvia. The metal production and processing sector has an impact on air quality due to polluting substances which are released in the air from metal treatment processes. Therefore it is necessary to determine the total volume of emissions produced by the metal production and processing sector in Latvia. This article deals with the air polluting emissions of the Latvian metal production and processing industry, and sets the optimum sector emission volumes using the emissions benchmark methodology.

Pubule, Jelena; Zahare, Dace; Blumberga, Dagnija

2010-01-01

271

Enhancing the mechanical properties of cement paste by growing in-situ fiber reinforcement during hydration  

NASA Astrophysics Data System (ADS)

Efforts to improve the mechanical properties of concrete by modifying the cement paste matrix have focused entirely on strength enhancement. But the intrinsic brittleness of the cement paste matrix limits the possible improvement in the mechanical properties of concrete, and in particular the toughness of the material. Increasing the toughness of the cement paste matrix could lead to a reduction in flaw sensitivity by delaying unstable crack propagation. Consequently, the resistance of the material to cracking due to drying shrinkage, thermal shrinkage, expansive deterioration processes, and applied loads could increase considerably. The goal of this study was to grow in-situ fiber reinforcement in cement paste, a technique never before applied to cement-based materials, to enhance the toughness of the material. Ettringite, an existing, fiber-like hydration product was selected as the fiber reinforcement. Ettringite met all the necessary criteria to act as reinforcement in cement paste: adequate distribution in the matrix; adjustable volume fraction, aspect ratio and size; high stiffness along the fiber length; and finally compatibility with existing hydration products. Alkali-free accelerators were selected as the admixtures used to grow the ettringite in the cement paste. X-ray diffraction and scanning electron microscopy experiments were performed to study the volume fraction, distribution, size, and morphology of the ettringite crystals in the cement paste matrix (both plain and accelerator-containing). Mechanical tests (compression, splitting tension, flexural, compact tension) were used to evaluate the effect of the accelerators on the strength and toughness of cement paste. Microindentations on the surface of the cement paste matrix were performed to study the morphology of the cracks and the toughening mechanisms taking place. Through the characterization tests we identified that while more ettringite forms with the addition of the alkali-free accelerators, some of that ettringite forms in highly-porous inclusions distributed throughout the matrix. The compact tension specimen results showed that the accelerated specimens had a higher toughness and ductility compared to the control specimens. The dominant toughening mechanism identified was constrained microcracking, with the ettringite inclusions contributing to microcracking.

Constantinides, Margarita

272

How To Make Mulligan Stew: Process and Product Again.  

ERIC Educational Resources Information Center

The complexity of the writing process makes it more useful to isolate a variety of processes or parts of processes that can be taught and learned. A narrow view of writing as product leads to a misinterpretation of the process as a definite sequence--prewriting, writing, rewriting--when in fact it is much more recursive. Proper analysis of product

Gorrell, Robert M.

273

The transformation sequence of cement–asbestos slates up to 1200 °C and safe recycling of the reaction product in stoneware tile mixtures  

Microsoft Academic Search

Cement–asbestos is the main asbestos containing material still found in most of the European countries such as Italy. Man- and weathering-induced degradation of the cement–asbestos slates makes them a source of dispersion of asbestos fibres and represents a priority cause of concern. This concern is the main prompt for the actual policy of abatement and disposal of asbestos containing materials

A. F. Gualtieri; C. Cavenati; I. Zanatto; M. Meloni; G. Elmi; M. Lassinantti Gualtieri

2008-01-01

274

Bag-house dust used in clinkerization of portland cements  

SciTech Connect

Many industrial materials considered essential for supporting a better quality of life consume large amounts of energy for their production. Ordinary portland cement (OPC) is used widely as a building material, and its manufacture consumes much energy. In India, the cost of energy accounts for >40% of the total cost of cement manufacture. The cost to manufacture cement is expected to increase because of increasing demands for energy. Scientists are attempting to prepare OPC and other binding materials at lower cost by using agricultural and industrial wastes during clinkerization and by making blended cements. These measures decrease cost of production, conserve mineral resources and protect the environment by beneficial disposal of wastes. This article describes the effect of adding 10% bag-house dust to black meal used in vertical shaft kiln clinkerization in a cement miniplant. The hydration properties of OPC and blended cements made from control and experimental clinkers also have been studied.

Singh, N.B.; Bhattacharjee, K.N.; Shukla, A.K. [Univ. of Gorakhpur (India). Dept. of Chemistry

1995-12-01

275

Exergy analyses and parametric optimizations for different cogeneration power plants in cement industry  

Microsoft Academic Search

The cement production is an energy intensive industry with energy typically accounting for 50–60% of the production costs. In order to recover waste heat from the preheater exhaust and clinker cooler exhaust gases in cement plant, single flash steam cycle, dual-pressure steam cycle, organic Rankine cycle (ORC) and the Kalina cycle are used for cogeneration in cement plant. The exergy

Jiangfeng Wang; Yiping Dai; Lin Gao

2009-01-01

276

21 CFR 820.70 - Production and process controls.  

Code of Federal Regulations, 2010 CFR

...Where process controls are needed...define and control the manner... (2) Monitoring and control of process...to have an adverse effect on product...required to work temporarily...processes. When computers or...

2010-04-01

277

21 CFR 820.70 - Production and process controls.  

Code of Federal Regulations, 2010 CFR

...Where process controls are needed...define and control the manner... (2) Monitoring and control of process...to have an adverse effect on product...required to work temporarily...processes. When computers or...

2009-04-01

278

Bioreactor and process design for biohydrogen production.  

PubMed

Biohydrogen is regarded as an attractive future clean energy carrier due to its high energy content and environmental-friendly conversion. It has the potential for renewable biofuel to replace current hydrogen production which rely heavily on fossil fuels. While biohydrogen production is still in the early stage of development, there have been a variety of laboratory- and pilot-scale systems developed with promising potential. This work presents a review of advances in bioreactor and bioprocess design for biohydrogen production. The state-of-the art of biohydrogen production is discussed emphasizing on production pathways, factors affecting biohydrogen production, as well as bioreactor configuration and operation. Challenges and prospects of biohydrogen production are also outlined. PMID:21624834

Show, Kuan-Yeow; Lee, Duu-Jong; Chang, Jo-Shu

2011-09-01

279

Recycling of porcelain tile polishing residue in portland cement: hydration efficiency.  

PubMed

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. PMID:22316267

Pelisser, Fernando; Steiner, Luiz Renato; Bernardin, Adriano Michael

2012-02-21

280

Fractional exhaled nitric oxide among cement factory workers: a cross sectional study  

PubMed Central

Background It has been suggested that dust exposure causes airway inflammation among cement factory workers. However, there is limited information on the mechanisms of this effect. We explored any associations between total dust exposure and fractional exhaled nitric oxide (FENO) as a marker of airway eosinophilic inflammation among cement production workers in Tanzania. We also examined possible differences in FENO concentration between workers in different parts of the production line. Methodology We examined 127 cement workers and 28 controls from a mineral water factory. An electrochemistry-based NIOX MINO device was used to examine FENO concentration. Personal total dust was collected from the breathing zone of the study participants using 37?mm cellulose acetate filters placed in three-piece plastic cassettes. Interviews on workers’ background information were conducted in the Swahili language. Results We found equal concentrations of FENO among exposed workers and controls (geometric mean (GM)=16?ppb). The GM for total dust among the exposed workers and controls was 5.0 and 0.6?mg/m3, respectively. The FENO concentrations did not differ between the exposed workers with high (GM?5?mg/m3) and low (GM<5?mg/m3) total dust exposure. There was no significant difference in FENO concentration between workers in the two main stages of the cement production process. Conclusions We did not find any difference in FENO concentration between dust-exposed cement workers and controls, and there were similar FENO concentrations among workers in the two main stages of cement production.

Tungu, Alexander Mtemi; Bratveit, Magne; Mamuya, Simon D; Moen, Bente E

2013-01-01

281

Process for Converting Waste Glass Fiber into Value Added Products, Final Report  

SciTech Connect

Nature of the Event: Technology demonstration. The project successfully met all of its technical objectives. Albacem has signed an exclusive licensing agreement with Vitro Minerals Inc., a specialty minerals company, to commercialize the Albacem technology (website: www.vitrominerals.com). Location: The basic research for the project was conducted in Peoria, Illinois, and Atlanta, Georgia, with third-party laboratory verification carried out in Ontario, Canada. Pilot-scale trials (multi-ton) were conducted at a facility in South Carolina. Full-scale manufacturing facilities have been designed and are scheduled for construction by Vitro Minerals during 2006 at a location in the Georgia, North Carolina, and South Carolina tri-state area. The Technology: This technology consists of a process to eliminate solid wastes generated at glass fiber manufacturing facilities by converting them to value-added materials (VCAS Pozzolans) suitable for use in cement and concrete applications. This technology will help divert up to 250,000 tpy of discarded glass fiber manufacturing wastes into beneficial use applications in the concrete construction industry. This technology can also be used for processing glass fiber waste materials reclaimed from monofills at manufacturing facilities. The addition of take-back materials and reclamation from landfills can help supply over 500,000 tpy of glass fiber waste for processing into value added products. In the Albacem process, waste glass fiber is ground to a fine powder that effectively functions as a reactive pozzolanic admixture for use in portland ce¬ment-based building materials and products, such as concrete, mortars, terrazzo, tile, and grouts. Because the waste fiber from the glass manufacturing industry is vitreous, clean, and low in iron and alkalis, the resulting pozzolan is white in color and highly consistent in chemical composition. This white pozzolan, termed VCAS Pozzolan (for Vitreous Calcium-Alumino-Silicate). is especially suited for white concrete applications where it imparts desirable benefits such as increased long-term strength and improved long-term durability of concrete products. Two U.S. patents entitled have been issued to Albacem covering the technology. Third-party validation testing has confirmed that the pozzolanic product is an excellent, high performance material that conforms to a ASTM standards and improves the strength and durability of concrete. Currently, there are no known significant competing technologies to process glass fiber manufacturing by-products and con¬vert them into value-added products. Most glass fiber-forming and fabrication wastes continue to be disposed in landfills at significant costs and with associated negative environmental impact. It is estimated that in a typical glass fiber manufactur¬ing facility, 10-20% by weight of the processed glass material is sent for dis¬posal to a landfill. Today, supplementary ce¬menting materials or mineral admixtures are key to achieving strong and durable concrete. Recovered materials such as coal fly ash, ground granulated blast furnace slag and silica fume are widely accepted and used in concrete all over the world, espe¬cially in the construction of “high performance” structures such as massive dams, bridges, subway tunnels, etc. These min¬eral admixtures are not suitable for white concrete and light-colored architectural concrete applications. Converting waste glass fibers into a high performance white pozzolan would allow white concrete producers to gain from the same durability benefits currently realized by gray concrete producers. Description of the Benefit: Albacem’s technology will enable the glass fiber industry to eliminate nearly 100% of its glass fiber produc¬tion waste streams by converting them into viable value-added products. With this technology, the glass industry can prevent the landfilling of about 250,000 tons of waste glass fiber annually. Glass manufacturers will realize improved production efficiency by reducing process costs through the elimination of solid was

Hemmings, Raymond T.

2005-12-31

282

Genetic improvement of processes yielding microbial products.  

PubMed

Although microorganisms are extremely good in presenting us with an amazing array of valuable products, they usually produce them only in amounts that they need for their own benefit; thus, they tend not to overproduce their metabolites. In strain improvement programs, a strain producing a high titer is usually the desired goal. Genetics has had a long history of contributing to the production of microbial products. The tremendous increases in fermentation productivity and the resulting decreases in costs have come about mainly by mutagenesis and screening/selection for higher producing microbial strains and the application of recombinant DNA technology. PMID:16472304

Adrio, Jose L; Demain, Arnold L

2006-03-01

283

Lunar cement and lunar concrete  

NASA Astrophysics Data System (ADS)

Results of a study to investigate methods of producing cements from lunar materials are presented. A chemical process and a differential volatilization process to enrich lime content in selected lunar materials were identified. One new cement made from lime and anorthite developed compressive strengths of 39 Mpa (5500 psi) for 1 inch paste cubes. The second, a hypothetical composition based on differential volatilization of basalt, formed a mineral glass which was activated with an alkaline additive. The 1 inch paste cubes, cured at 100C and 100 percent humidity, developed compressive strengths in excess of 49 Mpa (7100 psi). Also discussed are tests made with Apollo 16 lunar soil and an ongoing investigation of a proposed dry mix/steam injection procedure for casting concrete on the Moon.

Lin, T. D.

284

Lunar cement and lunar concrete  

NASA Technical Reports Server (NTRS)

Results of a study to investigate methods of producing cements from lunar materials are presented. A chemical process and a differential volatilization process to enrich lime content in selected lunar materials were identified. One new cement made from lime and anorthite developed compressive strengths of 39 Mpa (5500 psi) for 1 inch paste cubes. The second, a hypothetical composition based on differential volatilization of basalt, formed a mineral glass which was activated with an alkaline additive. The 1 inch paste cubes, cured at 100C and 100 percent humidity, developed compressive strengths in excess of 49 Mpa (7100 psi). Also discussed are tests made with Apollo 16 lunar soil and an ongoing investigation of a proposed dry mix/steam injection procedure for casting concrete on the Moon.

Lin, T. D.

1991-01-01

285

Upstream processes in antibody production: Evaluation of critical parameters  

Microsoft Academic Search

The demand for monoclonal antibody for therapeutic and diagnostic applications is rising constantly which puts up a need to bring down the cost of its production. In this context it becomes a prerequisite to improve the efficiency of the existing processes used for monoclonal antibody production. This review describes various upstream processes used for monoclonal antibody production and evaluates critical

Era Jain; Ashok Kumar

2008-01-01

286

Processing of alkali antimony intermediate products in a lead refinery  

Microsoft Academic Search

In a lead refinery, caustic soda is used in several technological operations, so that several alkali intermediate products are obtained. Depending on the process type and the lead refinary location, there are several possibilities for processing the alkali intermediate lead products, as well as soda regeneration from these intermediate products.

Branislav G. Nikoli?

1997-01-01

287

Development of environmental performance indicators for textile process and product  

Microsoft Academic Search

The increasing demand for environmental performance evaluation of industry requires development of sector-specific environmental performance indicators (EPIs). For the consumer product manufacturing industry, in this case the textile industry, the need to evaluate environmental performance both from process and product life cycle perspectives leads to development of EPIs of process and product dimensions. Such types of EPIs have been developed,

Xin Ren

2000-01-01

288

Technological decision process at lean production system  

Microsoft Academic Search

The research is a qualitative study about as some typical technological decision is made in manufacturing environmental using lean production principles. For example: changes in production line, replacement of a machine or choice of a new machine. The method was an interview in deeply done with three former executives from Brazilian subsidiary of Toyota. In investigation was found some steps

Alvair Silveira Torres Jr; Ana Gati Wechsler

2008-01-01

289

Hydrogen in the Methanol Production Process  

ERIC Educational Resources Information Center

Hydrogen is a very important industrial gas in chemical processes. It is very volatile; therefore, it can escape from the process units and its mass balance is not always correct. In many industrial processes where hydrogen is reacted, kinetics are often related to hydrogen pressure. The right thermodynamic properties of hydrogen can be found for…

Kralj, Anita Kovac; Glavic, Peter

2006-01-01

290

Process influence on product CDM ESD sensitivity  

Microsoft Academic Search

Effective ESD protection circuit design has become challenging due to rapid advances in process technology. This study was launched to address those concerns and to look for the process windows that preserve CDM ESD robustness for given ESD protection designs in deep sub micron technologies. Experimental results for 0.18 µm integrated CPU's together with process window effects on CDM robustness

Boris Lisenker

2002-01-01

291

Productive Skills for Process Operatives. Skills Review.  

ERIC Educational Resources Information Center

A study of process operatives examined the developments in processing work in 20 organizations within the chemical and food and drink processing industries. Seven exploratory interviews were followed by 20 employer interviews. Technological innovations caused job losses and layoffs. Organizational responses adopted to meet increasing competitive…

Giles, L.; Kodz, J.; Evans, C.

292

Conversion of historic waste treatment process for production of an LDR and WIPP/WAC compliant TRU wasteform  

SciTech Connect

In support of the historic weapons production mission at the, Rocky Flats Environmental Technology Site (RFETS), several liquid waste treatment processes were designed, built and operated for treatment of plutonium-contaminated aqueous waste. Most of these @ processes ultimately resulted in the production of a cemented wasteform. One of these treatment processes was the Miscellaneous Aqueous Waste Handling and Solidification Process, commonly referred to as the Bottlebox process. Due to a lack of processing demand, Bottlebox operations were curtailed in late 1989. Starting in 1992, a treatment capability for stabilization of miscellaneous, Resource Conservation and Recovery Act (RCRA) hazardous, plutonium-nitrate solutions was identified. This treatment was required to address potentially unsafe storage conditions for these liquids. The treatment would produce a TRU wasteform. It thus became necessary to restart the Bottlebox process, but under vastly different conditions and constraints than existed prior to its curtailment. This paper provides a description of the historical Bottlebox process and process controls; and then describes, in detail, all of the process and process control changes that were implemented to convert the treatment system such that a Waste Isolation Pilot Plant (WIPP) and a Land Disposal Requirements (LDR) compliant wasteform would be produced. The rationale for imposition of LDRs on a TRU wasteform is discussed. In addition, this paper discusses the program changes implemented to meet modem criticality safety, Conduct of Operations, and Department of Energy Nuclear Facility restart requirements.

Dunn, R.P.; Wagner, R.A.

1997-03-01

293

Reaction of CO2 and brine at the interface between Portland cement and casing steel: Application to CO2 sequestration  

NASA Astrophysics Data System (ADS)

Prediction of CO2 leakage through wellbore systems is a multiscale problem in geologic sequestration. In order for wellbore leakage to occur, km-scale processes must deliver CO2 from the point of injection to the wellbore. But, in order for the wellbore to actually leak, ?m-scale processes must operate to allow CO2 to flow up the wellbore. In this study, we describe experiments and modeling of microscale processes accompanying CO2 leakage along the cement-casing interface. This work fits within a broader predictive study of CO2 sequestration performance (Viswanathan et al. 2008, Env Sci and Tech, in press) that includes calculation of CO2-migration times to wellbores. Experiments carried out in this report consisted of synthetic wellbore systems constructed of Portland cement and casing-grade steel in which a mixture of CO2 and brine were forced along the cement-casing interface at in situ sequestration conditions (40 °C and 14 MPa). The CO2-brine mixture was pre- equilibrated by flow through limestone before encountering the cement-casing composite. (The limestone- equilibrated fluid was calculated to be strongly out of equilibrium with both cement and the casing.) We used a high CO2-brine flux (10-20 ml/hour along the interface) and hypothesized that the interface would widen with time due to dissolution of either or both cement and steel. In addition to experiments, we conducted reactive transport modeling of cement reactivity using FLOTRAN, which was modified to allow representation of solid solution in the dominant cement phase, calcium-silicate-hydrate. We also developed a corrosion model for the steel. The experimental results showed that the steel was more reactive than the Portland cement. Extensive deposits or oxidation products of FeCO3-rich material developed at the interface and in some places led to an apparent closure of the interface despite the large flux through the system. In contrast, alteration of the cement appeared to be limited by diffusion of CO2 into the cement matrix and carbonation of the cement to CaCO3. The cement interface did not appear to have been significantly eroded. The experiment was used to calibrate numerical models for corrosion rates and for cement carbonation. These results were applied to interpret samples recovered from a CO2-enhanced oil recovery field (SACROC in West Texas; Carey et al. 2007, Int J. Greenhouse Gas Control, 1: 75-85). The results suggest that CO2-brine flux must have been limited along the cement-casing interface because the casing showed very little corrosion. They also suggest that CO2 penetration along the cement-formation interface was limited in volume because the depth of carbonation at SACROC was limited. These microscale models suggest that cement-casing flow has the potential to be self-limiting due to precipitation of CO2 and that standard logging measurements of casing integrity can be used to assess whether significant flow of CO2-brine has occurred at the casing interface.

Carey, J. W.; Zhang, J.; Lichtner, P. C.; Grigg, R.; Svec, B.; Pawar, R.

2008-12-01

294

Cement-based stabilization/solidification of metal plating industry sludge.  

PubMed

This study examines the cement-based Stabilization/Solidification (S/S) technique of sludge produced from a metal plating industry. The sludge samples were characterized in terms of pH and heavy metal content (Cr, Cu, Fe, Ni, Pb and Zn). The leachability of the sludge was estimated using the Toxicity Characteristic Leaching Procedure (TCLP). Two binder mixtures were used for the S/S process, fly ash/cement and zeolite/cement. The weight ratio of the binder mixtures was optimized to achieve the highest strength. The optimum ratio binder mixtures was mixed with sludge samples of different weight ratios and cured for 28 days in order to find the S/S products with the highest strength and the lowest leachability. PMID:11501310

Savvides, C; Papadopoulos, A; Haralambous, K J; Loizidou, M

2001-01-01

295

A new electrolytic magnesium production process  

NASA Astrophysics Data System (ADS)

In this article, existing magnesium chloride electrolysis and thermal magnesium oxide reduction processes for producing magnesium are described and their limitations are pointed out. The theoretical background of a patented new process is outlined. In this process, magnesium oxide is dissolved in a rare-earth-chloride-containing electrolyte and electrolyzed to produce magnesium and oxygen like that of alumina in the Hall-Héroult process. It is also shown that the efficiency of the existing magnesium chloride electrolysis process should be improved greatly by adding a rare-earth chloride. In both cases, the magnesium produced is expected to be free from detrimental iron, nickel, copper, and boron impurities.

Sharma, Ram A.

1996-10-01

296

About Calcium Phosphate Cements (CPC)  

NASA Astrophysics Data System (ADS)

Calcium phosphate cements (CPC) are used in orthopaedic surgery as bone substitution and fixation of metallic implants, showing advantages with respect to other materials like polymeric cements or ceramic blocks also used for bone repair. For example, they are easy to shape and fill bone defects, react at low temperature and their setting product is hydroxyapatite, mineral from it's composed the inorganic part of the bone, resulting a bioabsorbable material that can be replaced by new bone. Nevertheless there are still some complications like their low absorption rate, inyectability, setting times and their low strength that limits their use to only non load bearing applications. In this work we present a brief resume of some investigations that has been proposed to solve some of these problems, like the addition of phosphates solutions or seeds to increase the reaction rate, or fibers and hard particles to produce a composite material.

Piñera, Silvia; Piña, Cristina

2006-09-01

297

Use of fine-grained shredder dust as a cement admixture after a melting, rapid-cooling and pulverizing process  

Microsoft Academic Search

Shredder dust is a residue, which is removed from valuable ferrous metals found in scrap automobile and electronic waste. It is also an industrial waste byproduct which, under legislation in place since April 1996, must be disposed of in landfill sites. One method of disposing shredder dust is by scorification, however, this is a costly process and therefore impractical. Costs

Kohji Kakimoto; Yasuko Nakano; Takehiro Yamasaki; Keisuke Shimizu; Takashi Idemitsu

2004-01-01

298

Reactions of fly ash with calcium aluminate cement and calcium sulphate  

Microsoft Academic Search

The hydration processes in the ternary system fly ash\\/calcium aluminate cement\\/calcium sulphate (FA\\/CAC\\/C$) at 20°C were investigated; six compositions from the ternary system FA\\/CAC\\/C$ were selected for this study. The nature of the reaction products in these pastes were analysed by X-ray diffraction (XRD) and infrared spectroscopy (FTIR). At four days reaction time, the main hydration reaction product in these

Lucía Fernández-Carrasco; E. Vázquez

2009-01-01

299

Dried food product and a process for producing the product  

US Patent & Trademark Office Database

This invention relates to a food snack comprising light, crispy wafers of dried minced food, typically dried minced meat and a process for making the food snack. The process includes the steps of dicing and mincing the food, feeding the food into a sausage casing, freezing the food in the casing, cutting the food into slices and drying the slices.

2002-05-07

300

Strength of cemented grains  

NASA Astrophysics Data System (ADS)

We conducted compaction tests (isotropic drained loading) on randomly packed glass beads that were a) uncemented and b) cemented by epoxy at their contacts. In the latter case, the volume of the epoxy accounted for 10 percent of the pore space. Intensive crushing of grains was observed in the first case at about 50 MPa. In the second case, the cemented grains stayed intact, the failure being localized within the epoxy. Therefore, even small amounts of cement at contacts prevent the failure of grains. Theoretically, this effect follows from our theory of cemented granular materials: stress concentration is high at the contacts of uncemented grains, whereas even small amounts of relatively soft cement result in a more uniform stress distribution over a larger contact area.

Yin, Hezhu; Dvorkin, Jack

1994-05-01

301

ULTRA-LIGHTWEIGHT CEMENT  

SciTech Connect

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.

Fred Sabins

2002-01-23

302

Paleoenvironmental Controls on Early Cementation of Organic-Rich Shales in the Eagle Ford Group  

NASA Astrophysics Data System (ADS)

Early carbonate cements have the potential to alter fracture toughness, and carbonate can be either promoted or inhibited by microbial processes in different redox zones. It is therefore possible that basin redox evolution could indirectly control early diagenesis and modify reservoir properties of corresponding shale units. The goals of this study are to analyze geochemical characteristics of the Late Cretaceous Eagle Ford Group in McMullen County, Texas in order to test the hypotheses that (1) the redox state of the water column controlled carbonate cement abundance and (2) carbonate cement lowered organic matter content by volumetric dilution. An X-ray analytical microscope was used to map elemental compositions of fresh core samples spanning the Eagle Ford Group. Resultant maps were used to characterize carbonate cements and to estimate the redox state of the overlying water column during deposition as proxied by the relative abundances of the trace metals Mo, V, Cr, and Zn. Preliminary results indicate that cementation occurred early relative to compaction. Ti-K?1-normalized Mo K?1 and Ca K?1 fluorescence intensities are positively correlated throughout the unit, suggesting that carbonate cementation was promoted by basin euxinia. Total organic carbon is negatively correlated with (Ca K?1)/(Ti K?1) fluorescence ratio in the upper Eagle Ford Group, consistent with volumetric dilution of sedimentary organic matter by diagenetic cementation prior to compaction. In contrast, there is no significant correlation between total organic carbon and carbonate content in the more organic-rich lower Eagle Ford Group, suggesting that variations in organic matter production, preservation, or dilution by siliciclastic input were also important in controlling final organic content.

Kruse, K.; Tice, M. M.

2013-12-01

303

Cement rotary kiln control: A supervised adaptive model predictive approach  

Microsoft Academic Search

Considering the need of an advanced process control in cement industry, this paper presents an adaptive model predictive algorithm to control a white cement rotary kiln. As any other burning process, the control scenario is to expect the controller to regulate the temperature and the period of baking a fixed quantity of raw material as desired, as well as to

Javaneh Ziatabari; Alireza Fatehi; Mohamad T. H. Beheshti

2008-01-01

304

Acoustic response of cemented granular sedimentary rocks: Molecular dynamics modeling  

Microsoft Academic Search

The effect of cementation processes on the acoustical properties of sands is studied via molecular dynamics simulation methods. We propose numerical methods where the initial uncemented sand is built by simulating the settling process of sediments. Uncemented samples of different porosity are considered by emulating natural mechanical compaction of sediments due to overburden. Cementation is considered through a particle-based model

Xavier García; Ernesto Medina

2007-01-01

305

Development of an advanced continuous mild gasification process for the production of co-products. Quarterly report, January--March, 1996  

SciTech Connect

Determination of the best furnace for a commercial coke plant is underway. A shuttle or tunnel kiln has economic advantage over a rotary hearth design. Production of 20 tons of coke in a small shuttle kiln is near completion which will provide experience for this design. Twenty tons of CTC continuous coke are being produced for testing at a General Motors` foundry. The production is approximately 75 percent complete. During this production, variables of the process are being studied to aid in design of a commercial coke plant. Raw material composition, blending, briquetting variables, and calcining heat profile are the major areas of interest. Western SynCoal Company produces a dried coal product from sub-bituminous coal. This upgraded product was evaluated for producing coke products by blending char from this coal product with the coal product along with suitable binders. The green briquettes were then calcined to produce coke. The resulting coke was judged to be usable as part of a cupola coke charge or as a fuel in cement kilns and sugar beet furnaces.

O`Neal, G.W.

1996-04-01

306

SOA Production From Cloud Processing of Glycolaldehyde  

NASA Astrophysics Data System (ADS)

Recent studies suggest that aqueous cloud chemistry contributes to secondary organic aerosol (SOA) production. Gas phase primary precursors, such as ethene and isoprene, can oxidize in the interstitial spaces of clouds to form water-soluble species, including glycolaldehyde. These water-soluble products can partition into cloud droplets and undergo further oxidation (e.g., via hydroxyl radicals). If low-volatility products (e.g., oxalate) are formed, these products can remain in the particle phase following droplet evaporation, forming organic aerosol. Organic aerosol plays an important role in cloud microphysics, visibility, and human health, yet little is known about aqueous phase reaction pathways and products that contribute to SOA. The kinetics of aqueous phase glycolaldehyde oxidation were studied and products were identified. Hydroxyl radical was generated via continuous UV photolysis of hydrogen peroxide inside a glass photochemical vessel. The reaction of glycolaldehyde and hydroxyl radical was monitored in real-time via continuous electrospray ionization mass spectrometry (ESI-MS). Organic products (acids and aldehydes) formed and destroyed during the reaction were identified and quantified via negative and positive mode ionization. Based on ESI-MS data obtained, glycolaldehyde is oxidized via hydroxyl radical to glycolic acid, glyoxylic acid, and ultimately oxalic acid, as previously suggested. In addition, several unexpected higher molecular weight compounds were produced, and identification of these reaction products is currently underway. The results obtained from this study serve to validate and refine the aqueous SOA-producing pathway for glycolaldehyde in cloud chemistry models and can be used to increase the accuracy of SOA prediction in atmospheric air quality and climate models.

Perri, M. J.; Seitzinger, S. P.; Tan, Y.; Turpin, B. J.

2007-12-01

307

Process for Energy Production by Means of Underground Gasification.  

National Technical Information Service (NTIS)

A process is described for energy production by underground gasification of bituminous deposits, especially low-grade ones, in which thermal energy is supplied to the deposits intersected by boreholes for gas production from the bituminous rock masses, ch...

F. Jansen

1975-01-01

308

Global production networks and China's processing trade  

Microsoft Academic Search

This paper unveils a systematic pattern in China's processing trade. In a cross-section of Chinese provinces, the average distance traveled by processing imports (import distance) is negatively correlated to the average distance traveled by processing exports (export distance). To explain this pattern, we set up a three-country industry-equilibrium model in which heterogeneous firms from two advanced countries, East and West,

Alyson C. Ma; Ari Van Assche; Chang Hong

2009-01-01

309

Large strains in cemented granular aggregates: Elastic-plastic cement  

Microsoft Academic Search

We describe large-strain behavior of cemented geomaterials by modeling the deformation of a random pack of identical cemented spheres. In this model we assume that the grains are elastic but that the intergranular cement becomes partly plastic as local stresses meet a plasticity condition. This plasticity condition for a thin elastic-plastic cement layer is derived based on the von Mises

Jack Dvorkin

1996-01-01

310

Combined production-maintenance decisions in situations with process deterioration  

Microsoft Academic Search

This article addresses an imperfect production system with process deterioration and how best to maintain the system. In the system there is a constant percentage to produce defective products in the ‘in-control’ state and a higher percentage to produce defective products in the ‘out-of-control’ state. The production process may shift randomly from an in-control state to an out-of-control state during

Yu-Chung Tsao

2012-01-01

311

Hydrometallurgical Processes Development for Zinc Oxide Production from Waelz Oxide  

Microsoft Academic Search

This study is focused on the development of a hydrometallurgical process which allows the zinc recovery from Waelz oxide (WO).\\u000a This process is aimed to zinc oxide production. So, it must allow the production of a widely used compound, mainly in tyre\\u000a and ceramics production processes, from industrial residues such as EAF dusts considered as Toxic and Hazardous Wastes (THWs),

D. Herrero; P. L. Arias; J. F. Cambra; N. Antuñano

2010-01-01

312

Cemented Volcanic Soils, Martian Spectra and Implications for the Martian Climate  

NASA Astrophysics Data System (ADS)

Cemented volcanic crusts are studied to learn about their composition, formation processes, and implications for climate interactions with the surface on Mars. Such carbonate, sulfate and opal crusts may be present in cemented soil units on Mars.

Bishop, J. L.; Schiffman, P.; Drief, A.; Southard, R. J.

2004-03-01

313

Blast Furnace Slag-Cement Grout Blends for the Immobilization of Technetium-Containing Wastes.  

National Technical Information Service (NTIS)

Mixed low-level radioactive and chemically toxic process treatment wastes from the Portsmouth Gaseous Diffusion Plant are stabilized by solidification in cement-based grouts. Conventional portland cement and fly ash grouts are shown to be very effective f...

W. D. Bostick J. L. Shoemaker R. L. Fellows R. D. Spence T. M. Gilliam

1988-01-01

314

A Cost Analysis: Processing Maple Syrup Products.  

National Technical Information Service (NTIS)

A cost analysis of processing maple sap to syrup for three fuel types, oil-, wood-, and LP gas-fired evaporators, indicates that: (1) fuel, capital, and labor are the major cost components of processing sap to syrup; (2) wood-fired evaporators show a slig...

N. K. Huyler L. D. Garrett

1979-01-01

315

Preventive maintenance holds key to processing productivity  

Microsoft Academic Search

The popular term ''preventive maintenance'' brings to mind lubrication schedules, wear gauges and spare parts. Yet somehow, processing equipment--crushers, washers, conveyors, feeders, screens, etc.--continues to go down just when it hurts most. And when a part of the processing line stops, everything stops. Regular lubrication, spares and the like are indeed part of effective preventive maintenance. But other considerations, some

Carrieri

1983-01-01

316

Technical Writing: Process and Product. Third Edition.  

ERIC Educational Resources Information Center

This book guides students through the entire writing process--prewriting, writing, and rewriting--developing an easy-to-use, step-by-step technique for writing the types of documents they will encounter on the job. It engages students in the writing process and encourages hands-on application as well as discussions about ethics, audience…

Gerson, Sharon J.; Gerson, Steven M.

317

Experimental Micromechanics of the Cement-Bone Interface  

PubMed Central

Despite the widespread use of cement as a means of fixation of implants to bone, surprisingly little is known about the micromechanical behavior in terms of the local interfacial motion. In this work, we utilized digital image correlation techniques to quantify the micromechanics of the cement–bone interface of laboratory-prepared cemented total hip replacements subjected to nondestructive, quasistatic tensile and compressive loading. Upon loading, the majority of the displacement response localized at the contact interface region between cement and bone. The contact interface was more compliant (p = 0.0001) in tension (0.0067 ± 0.0039 mm/MPa) than compression (0.0051 ± 0.0031 mm/MPa), and substantial hysteresis occurred due to sliding contact between cement and bone. The tensile strength of the cement–bone interface was inversely proportional to the compliance of the interface and proportional to the cement/bone contact area. When loaded beyond the ultimate strength, the strain localization process continued at the contact interface between cement and bonewith microcracking (damage) to both. More overalldamage occurredto the cement than to the bone. The opening and closing at the contact interface from loading could serve as a conduit for submicron size particles. In addition, the cement mantle is not mechanically supportedby surrounding bone as optimally as is commonly assumed. Both effects may influence the longevity of the reconstruction and could be considered in preclinical tests.

Mann, Kenneth A.; Miller, Mark A.; Cleary, Richard J.; Janssen, Dennis; Verdonschot, Nico

2008-01-01

318

Multivariable decoupling Fuzzy-Smith predictive control of cement rotary kiln temperature system  

Microsoft Academic Search

Cement rotary kiln thermal process can be viewed as an uncertain and complex temperature system with multivariable, strong coupling and time delays. The performance of combustion process control system will directly affect the quality of cement clinker, so it is necessary to control the temperature of every part in the kiln strictly in order to ensure the quality of cement

Li Dong-Sheng; Fang Yi-Ming; Li Jian-Xiong; Deng Li-Guang

2010-01-01

319

Developmental study of a low-pH magnesium phosphate cement for environmental applications.  

PubMed

This paper presents a laboratory investigation into the development of a low-pH magnesium phosphate-based cement for use in in-situ stabilisation/solidification systems, as a more effective alternative to Portland cement. The idea is to develop a cement-based binder with a low enough pH to facilitate biodegradation in combination with stabilisation/solidification processes. Potassium dihydrogen orthophosphate was selected as the phosphate source, dead-burned magnesia as the magnesium source and boric acid as the retarder. The range of mixes were tested primarily on their pH development which was found to be in the range of 6-9.5 for a magnesia to phosphate ratio range of 1:1 to 1:5. The testing revealed a dense microstructure, high early-age strength development and low volume expansion of the developed cement. Observed fracturing of some of the cured cement samples has been related to the curing conditions and the impurities present in the magnesia. On the basis of microstructural examination, observed white crystalline deposits on cured samples are likely to be a reaction product of magnesia and potassium dihydrogen phosphate. PMID:18341149

Iyengar, S R; Al-Tabbaa, Abir

2007-12-01

320

Differential scanning calorimetry study of ordinary Portland cement paste containing metakaolin and theoretical approach of metakaolin activity  

Microsoft Academic Search

This paper aims to investigate the hydration and pozzolanic reactions in cement pastes with different levels of metakaolin replacement, using differential scanning calorimetry (DSC) and theoretical analysis based on reaction stoichiometry. It was found that the DSC technique could follow the hydration process quantitatively by measuring the peak temperature and enthalpy corresponding to decomposition of hydration products, as functions of

W Sha; G. B Pereira

2001-01-01

321

21 CFR 113.100 - Processing and production records.  

Code of Federal Regulations, 2010 CFR

...SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION...PROCESSED LOW-ACID FOODS PACKAGED IN HERMETICALLY...Aseptic processing and packaging systems. Product...of container. (6) Food preservation methods wherein...

2010-04-01

322

21 CFR 113.100 - Processing and production records.  

Code of Federal Regulations, 2010 CFR

...SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION...PROCESSED LOW-ACID FOODS PACKAGED IN HERMETICALLY...Aseptic processing and packaging systems. Product...of container. (6) Food preservation methods wherein...

2009-04-01

323

MAINTAINING SOIL PROCESSES FOR PLANT PRODUCTIVITY AND COMMUNITY DYNAMICS  

EPA Science Inventory

Rangeland soil biota affect soil properties and processes that control the availability of water and nutrients that are essential for the maintenance of productivity and vegetation composition. oil processes mediated by soil biota include decomposition, nutrient immobilization an...

324

An Economic Order Quantity Model with Demand-Dependent Unit Production Cost and Imperfect Production Processes  

Microsoft Academic Search

The classical economic order quantity (EOQ) model assumes that items produced are of perfect quality and that die unit cost of production is independent of demand. Product quality is not always perfect but directly affected by the reliability of the production process used to produce the products. In addition, a relationship between unit production cost and demand may exist under

T. C. E. CHENG

1991-01-01

325

Phosphate based oil well cements  

Microsoft Academic Search

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

Ramkumar Natarajan

2005-01-01

326

Bond strength of permanent cements in cementing cast to crown different core build-up materials.  

PubMed

The purpose of this laboratory investigation was to evaluate the bond strength of permanent cement (Duo-cement Kit, Meron, Durelon) to commonly used core build-up materials (President, Dyract AP, Ionofil, Vitremer). Sixty specimens (five of each product) were fabricated as a canine core build- up. Full crown castings were made to fit each core specimen. Full crown castings were cemented to core samples and stored at 37 degrees C and 100% humidity for 10 days. After storage, the bond strength was measured with a Haunsfield tensometer in tensile mode at a crosshead speed of 5 mm/min. Statistical evaluation was performed with univariate analysis of variance (P<0.001). The cement types affected the bond strength of full crown castings to core materials (F: 14.80; P<0.001). The interaction between the cement and core materials was significant (F: 3.69; P<0.01). According to the Duncan's test it was found that the values of Duo-cement were statistically different from the other cements. PMID:15287556

Bayindir, Yusuf Ziya; Bayindir, Funda; Akyil, M Samil

2004-06-01

327

Fluid-Bed Process for SYNROC Production.  

National Technical Information Service (NTIS)

SYNROC is a titanate-based ceramic waste developed for the immobilization of high-level nuclear reactor waste. Lawrence Livermore National Laboratory (LLNL) has investigated a fluid-bed technique for the large-scale production of SYNROC precursor powders....

F. J. Ackerman J. Z. Grens F. J. Ryerson C. L. Hoenig F. Bazan

1983-01-01

328

Process for Preparing Sterilized Concentrated Milk Products.  

National Technical Information Service (NTIS)

The high temperature-short time sterilized concentrated milk product has improved storage stability. The milk has incorporated in it from 0.003 to 0.015 mole per kilogram of milk solids-not-fat of a water soluble, non-toxic, divalent salt of a metal selec...

A. Leviton M. J. Pallansch

1965-01-01

329

Polymerisation stress modelling in acrylic bone cement.  

PubMed

Fatigue failure of the cement mantle has been proposed as one of the failure processes contributing to aseptic loosening of cemented joint replacements. It has also been suggested that fatigue failure is dramatically accelerated by residual stress generated during the cement polymerisation process. Previous computational models of the polymerisation process have investigated only the latter part of polymerisation by assuming both instantaneous hardening of the material (a stress locking point) and that all residual stress results from thermal shrinkage after this stress locking point. In this study, finite element models which use the local degree of polymerisation to calculate material properties and shrinkage have been used to predict residual stresses in two models of total hip replacement cement mantles. Results indicate that the final value of cement mantle stress may not be the highest stresses that the cement is subjected to during the polymerisation process. Two models are presented, a 2-dimensional model, which was adapted from a similar model in the literature (Lennon and Prendergast, 2002) and a 3-dimensional concentric-cylinders model. In both cases a chemical kinetics model was used to predict the progress of the polymerisation reaction and a second linear model used to predict cement mechanical properties and density, and so stress generation and volume change, over time. There was good agreement of the results of the 2D model with its counterpart in the literature. For the 3D model, the final residual stress magnitudes and patterns showed good agreement with similar physical and computational models in the literature. PMID:19959169

Briscoe, A; New, A

2010-03-22

330

Planning development processes for complex products  

Microsoft Academic Search

Efficient planning of design processes is of critical importance to meet tight deadlines and budgets; and the development\\u000a of process planning tools is a lively research area. This paper describes current planning practice in industry and the challenges\\u000a associated with it. In industry, a multitude of plans are used in parallel each focussing on a different aspect. The units\\u000a of

Claudia M. EckertP; P. John Clarkson

2010-01-01

331

ULTRA-LIGHTWEIGHT CEMENT  

SciTech Connect

The objective of this project is to develop an improved ultra-lightweight cement using ultra-lightweight hollow glass spheres (ULHS). This report discusses testing that was performed for analyzing the alkali-silica reactivity of ULHS in cement slurries. Laboratory testing during the eleventh quarter focused on evaluation of the alkali-silica reaction of eight different cement compositions, four of which contain ULHS. This report provides a progress summary of ASR testing. The original laboratory procedure for measuring set cement expansion resulted in unacceptable erosion of the test specimens. In subsequent tests, a different expansion procedure was implemented and an alternate curing method for cements formulated with TXI Lightweight cement was employed to prevent sample failure caused by thermal shock. The results obtained with the modified procedure showed improvement over data obtained with the original procedure, but data for some compositions were still questionable. Additional modification of test procedures for compositions containing TXI Lightweight cement were implemented and testing is ongoing.

Fred Sabins

2003-07-31

332

Coupled X-ray Microtomography Imaging and Computational Fluid Dynamics Modeling for Evaluation of Wellbore Cement Fracture Evolution  

NASA Astrophysics Data System (ADS)

Composite Portland cement-basalt caprock cores with fractures, as well as neat Portland cement columns, were prepared to understand the geochemical and geomechanical effects on the integrity of wellbores with defects during geologic carbon sequestration. The samples were reacted with CO2-saturated groundwater at 50 degrees Celsius and 10 MPa for 3 months under static conditions, while one cement-basalt core was subjected to mechanical stress at 2.7 MPa before the CO2 reaction. X-ray microtomography (XMT) provided three-dimensional (3-D) visualization of the opening and interconnection of cement fractures due to mechanical stress. Computational fluid dynamics (CFD) modeling further revealed that this stress led to the increase in fluid flow and hence permeability. After the CO2-reaction, XMT images displayed that calcium carbonate precipitation occurred extensively within the fractures in the cement matrix, but only partially along the fracture located at the cement-basalt interface. The 3-D visualization and CFD modeling also showed that the precipitation of calcium carbonate within the cement fractures after the CO2-reaction resulted in the opening of fractures due to crystallization-induced pressure, as well as disconnection of cement fractures and permeability decrease. The permeability calculated based on CFD modeling was in agreement with the experimentally determined permeability. The study also suggests that in deep geological reservoirs the geochemical and geomechanical processes have coupled effects on the fracture evolution and fluid flow. Finally, it is important to emphasize that XMT imaging coupled with CFD modeling represents a powerful tool to visualize and quantify fracture evolution and permeability in geologic materials and predict their behavior during geologic carbon sequestration or hydraulic fracturing for shale gas production and enhanced geothermal system.

Jung, H.; Kabilan, S.; Carson, J.; Kuprat, A.; Um, W.; Carroll, K. C.; Bonneville, A.; Fernandez, C.

2013-12-01

333

Low-cost process for hydrogen production  

DOEpatents

A method is provided for producing hydrogen and carbon black from hydrocarbon gases comprising mixing the hydrocarbon gases with a source of carbon and applying radiofrequency energy to the mixture. The hydrocarbon gases and the carbon can both be the products of gasification of coal, particularly the mild gasification of coal. A method is also provided for producing hydrogen and carbon monoxide by treating a mixture of hydrocarbon gases and steam with radio-frequency energy.

Cha, C.H.; Bauer, H.F.; Grimes, R.W.

1993-03-30

334

Low-cost process for hydrogen production  

DOEpatents

A method is provided for producing hydrogen and carbon black from hydrocarbon gases comprising mixing the hydrocarbon gases with a source of carbon and applying radiofrequency energy to the mixture. The hydrocarbon gases and the carbon can both be the products of gasification of coal, particularly the mild gasification of coal. A method is also provided for producing hydrogen an carbon monoxide by treating a mixture of hydrocarbon gases and steam with radio-frequency energy.

Cha, Chang Y. (Golden, CO); Bauer, Hans F. (Morgantown, WV); Grimes, Robert W. (Laramie, WY)

1993-01-01

335

Cement composite delivery system.  

PubMed

Several new and innovative techniques have recently been introduced that purport to increase the strength of polymethyl methacrylate bone cement. One of these concepts is the use of carbon and polymer fibers to form a cement composite. Bone cement composites usually 1% fiber, are very difficult to use clinically. The composite is very sticky and viscous, which precludes effective hand packing or the use of conventional delivery systems. A new delivery system for very viscous materials is presented and examples of in vitro application are shown. PMID:3453485

Convery, F R; Devine, S D; Hollis, J M; Woo, S L

1986-09-01

336

Energy auditing and recovery for dry type cement rotary kiln systems––A case study  

Microsoft Academic Search

Cement production has been one of the most energy intensive industries in the world. In order to produce clinker, rotary kilns are widely used in cement plants. This paper deals with the energy audit analysis of a dry type rotary kiln system working in a cement plant in Turkey. The kiln has a capacity of 600 ton-clinker per day. It

Tahsin Engin; Vedat Ari

2005-01-01

337

From Process to Product: Your Risk Process at Work  

NASA Technical Reports Server (NTRS)

The Space Life Sciences Directorate (SLSD) and Human Research Program (HRP) at the NASA/Johnson Space Center work together to address and manage the human health and performance risks associated with human space flight. This includes all human system requirements before, during, and after space flight, providing for research, and managing the risk of adverse long-term health outcomes for the crew. We previously described the framework and processes developed for identifying and managing these human system risks. The focus of this panel is to demonstrate how the implementation of the framework and associated processes has provided guidance in the management and communication of human system risks. The risks of early onset osteoporosis, CO2 exposure, and intracranial hypertension in particular have all benefitted from the processes developed for human system risk management. Moreover, we are continuing to develop capabilities, particularly in the area of information architecture, which will also be described. We are working to create a system whereby all risks and associated actions can be tracked and related to one another electronically. Such a system will enhance the management and communication capabilities for the human system risks, thereby increasing the benefit to researchers and flight surgeons.

Kundrot, Craig E.; Fogarty, Jenifer; Charles, John; Buquo, Lynn; Sibonga, Jean; Alexander, David; Horn, Wayne G.; Edwards, J. Michelle

2010-01-01

338

Critical mixing parameters for good control of cement slurry quality  

SciTech Connect

The cement mixing procedure can be split into a mechanical process that includes the wetting of the powder and the deflocculation and homogenization of the resulting suspension and a physicochemical process that includes the dissolution of some cement phases, the formation of supersaturated solutions, and the precipitation of cement hydrates. The mechanical process has been validated by inert suspensions of silica and barite and by cement slurries of various reactivities and physical characteristics (particle size distribution). The physicochemical process has been investigated systematically by looking at the precipitation kinetics, inert suspensions, and finally cement slurries. The relevant mixing parameters has been found to be the residence time of the slurry in the mixer and the rotational speed.

Vidick, B. (Dowell Schlumberger, Aberdeen (GB))

1990-07-01

339

An imperfect process strategy for a repairable product with production correction and maintenance  

Microsoft Academic Search

In imperfect production processes, this paper considers production correction and maintenance to break away out of control state. Production processes are classified into two types of state: one is the type I state (out-of-control state) and the other is the type II state (in-control state). The type I state involves adjustment of the production mechanism. Production correction is either imperfect;

Gwo-Liang Liao; Ya-Ting Chang; Bor-Ling Shaw; Hung Yu Huang

2010-01-01

340

Process for the production of hydrogen peroxide  

DOEpatents

An integrated membrane-based process method for producing hydrogen peroxide is provided comprising oxidizing hydrogenated anthraquinones with air bubbles which were created with a porous membrane, and then contacting the oxidized solution with a hydrophilic membrane to produce an organics free, H{sub 2}O{sub 2} laden permeate. 1 fig.

Datta, R.; Randhava, S.S.; Tsai, S.P.

1997-09-02

341

Developing distributed applications for integrated product and process design  

Microsoft Academic Search

A heterogeneous computing environment characterizes today's manufacturing situation. This is a stumbling block for the efficient implementation of manufacturing concepts such as integrated product and process design (IPPD). A computing environment for IPPD would require the seamless integration of the various product and process design software systems. The exchange of information between these systems should be efficient, compatible and synchronous.

F. Mervyn; A. Senthil Kumar; S. H. Bok; Andrew Y. C. Nee

2004-01-01

342

Economic production quantity and process quality: a multivariate approach  

Microsoft Academic Search

Purpose – The purpose of this paper is to study the interaction of economics of production with process quality, when multiple key quality characteristics are present. Specifically, the paper aims to analyse the possibility of investing in a production process to reduce its variances and the impact on a multivariate quality loss function. Design\\/methodology\\/approach – A bivariate inventory-planning model is

Weng M. Chan; Raafat N. Ibrahim; Paul B. Lochert

2005-01-01

343

The Calcination Process in a System for Washing, Calcinating, and Converting Treated Municipal Solid Waste Incinerator Fly Ash into Raw Material for the Cement Industry  

Microsoft Academic Search

Calcination is the second step in a washing-calcination-conversion system in which treated municipal solid waste incinerator fly ash and bottom ash can be reused as raw material in the cement industry and can decompose or stabilize hazardous compounds, reduce residue amounts, and alter residue characteristics. In this research, only fly ash is discussed. Chloride reduction is important if treated fly

Fenfen Zhu; Masaki Takaoka; Kazuyuki Oshita; Shinsuke Morisawa

2011-01-01

344

Process for Treating by Products of Lithium/Sulfur Hexafluoride.  

National Technical Information Service (NTIS)

A process is provided for treating the solid reaction by-products of lithium and sulfur hexafluoride. Lithium in the by-product solid waste is converted to lithium hydroxide. Lithium sulfide in the by-product is converted to lithium hydroxide. Lithium sul...

L. E. Lema

1995-01-01

345

Research on Process Planning for Product Multidisciplinary Cooperative Design  

Microsoft Academic Search

With the increasing complexity of product function and structure, product multidisciplinary cooperative design becomes fairly necessary. Between design task will have each kind of demonstration or latent relation and the interaction In product multidisciplinary cooperative design, it brings the difficulty for the task decomposition and the process planning. The task decomposition and the planning strategy was advanced focusing on the

Weihua Cui

2010-01-01

346

Integrated coke, asphalt and jet fuel production process and apparatus  

DOEpatents

A process and apparatus for the production of coke, asphalt and jet fuel m a feed of fossil fuels containing volatile carbon compounds therein is disclosed. The process includes the steps of pyrolyzing the feed in an entrained bed pyrolyzing means, separating the volatile pyrolysis products from the solid pyrolysis products removing at least one coke from the solid pyrolysis products, fractionating the volatile pyrolysis products to produce an overhead stream and a bottom stream which is useful as asphalt for road pavement, condensing the overhead stream to produce a condensed liquid fraction and a noncondensable, gaseous fraction, and removing water from the condensed liquid fraction to produce a jet fuel-containing product. The disclosed apparatus is useful for practicing the foregoing process. the process provides a useful method of mass producing and jet fuels from materials such as coal, oil shale and tar sands.

Shang, Jer Y. (McLean, VA)

1991-01-01

347

BD monomer and elastomer production processes.  

PubMed

The monomer 1,3 butadiene (BD) is a product of the petrochemical industry. It is used to make several elastomers including the very high volume styrene butadiene rubber (SBR) that comprises the bulk of automobile tires. It is also used to make polybutadiene rubber that is used in parts of tires, coatings, composites and other products. The monomer can be converted to chlorobutadiene (chloroprene) and used to make polychloroprene (neoprene). BD is one of the several olefins created by cracking hydrocarbons in the presence of steam. A mixed C4 stream from the steam cracker is then sent to a BD monomer extraction unit. Modern units typically use dimethyl formamide as the extraction solvent. SBR is commonly made by the copolymerization of BD and styrene, along with various additives to control the reaction, in a water emulsion. The reaction proceeds in a continuous chain of reactors until it is 'shortstopped' by a strong reducing agent. After removing unreacted monomers from the stabilized latex, it is blended, coagulated and dewatered. The resulting dry rubber crumb is bailed, film wrapped and stored in crates. The polymerization of BD to make polybutadiene rubber can be conducted as a water suspension type polymerization similar to SBR or in a solvent system followed by solvent recovery and transfer into water suspension. PMID:11397387

Lynch, J

2001-06-01

348

Product binding varies dramatically between processive and nonprocessive cellulase enzymes.  

PubMed

Cellulases hydrolyze ?-1,4 glycosidic linkages in cellulose, which are among the most prevalent and stable bonds in Nature. Cellulases comprise many glycoside hydrolase families and exist as processive or nonprocessive enzymes. Product inhibition negatively impacts cellulase action, but experimental measurements of product-binding constants vary significantly, and there is little consensus on the importance of this phenomenon. To provide molecular level insights into cellulase product inhibition, we examine the impact of product binding on processive and nonprocessive cellulases by calculating the binding free energy of cellobiose to the product sites of catalytic domains of processive and nonprocessive enzymes from glycoside hydrolase families 6 and 7. The results suggest that cellobiose binds to processive cellulases much more strongly than nonprocessive cellulases. We also predict that the presence of a cellodextrin bound in the reactant site of the catalytic domain, which is present during enzymatic catalysis, has no effect on product binding in nonprocessive cellulases, whereas it significantly increases product binding to processive cellulases. This difference in product binding correlates with hydrogen bonding between the substrate-side ligand and the cellobiose product in processive cellulase tunnels and the additional stabilization from the longer tunnel-forming loops. The hydrogen bonds between the substrate- and product-side ligands are disrupted by water in nonprocessive cellulase clefts, and the lack of long tunnel-forming loops results in lower affinity of the product ligand. These findings provide new insights into the large discrepancies reported for binding constants for cellulases and suggest that product inhibition will vary significantly based on the amount of productive binding for processive cellulases on cellulose. PMID:22648408

Bu, Lintao; Nimlos, Mark R; Shirts, Michael R; Ståhlberg, Jerry; Himmel, Michael E; Crowley, Michael F; Beckham, Gregg T

2012-07-13

349

SNG production by the Rockgas process  

Microsoft Academic Search

In the Rockgas process, coal is gasified within a highly turbulent sodium carbonate-based melt in a single-stage gasifier. The gasification is carried out either with air to produce a low-Btu gas or with oxygen and steam to produce a medium-Btu gas, which can be upgraded to substitute natural gas (SNG) by water gas shift, acid gas removal, methanation, and drying.

J. K. Rosemary; C. A. Trilling

1978-01-01

350

Production process for advanced space satellite system cables/interconnects.  

SciTech Connect

This production process was generated for the satellite system program cables/interconnects group, which in essences had no well defined production process. The driver for the development of a formalized process was based on the set backs, problem areas, challenges, and need improvements faced from within the program at Sandia National Laboratories. In addition, the formal production process was developed from the Master's program of Engineering Management for New Mexico Institute of Mining and Technology in Socorro New Mexico and submitted as a thesis to meet the institute's graduating requirements.

Mendoza, Luis A.

2007-12-01

351

Chemically reduced excess sludge production in the activated sludge process.  

PubMed

Excess sludge production from wastewater biological treatment process is highly, and the disposal of excess sludge will be forbidden in a near future, thus increased attention has been turned to look into potential technology for sludge reduction. Recently, some novel sludge reduction techniques have been developed based on chemical oxidation and metabolic uncoupling. This paper attempts to review those chemical-assisted sludge reduction processes, including sludge alkaline-thermal treatment, activated sludge-ozonation process, chlorination-combined activated sludge process, sludge reduction by metabolic uncouplers and high dissolved oxygen activated sludge process. In these combined activated sludge processes, excess sludge production can be reduced up to 100% without significant effect on process efficiency and stability. This paper would be useful when one is looking for appropriate environmentally and economically acceptable solutions for reducing or minimizing excess sludge production from wastewater biological treatment process. PMID:12656222

Liu, Yu

2003-01-01

352

Soil-Cement Study.  

National Technical Information Service (NTIS)

This study consisted of an examination of the compressive strengths of soil-cement mixtures on 15 construction projects from the standpoint of design and actual achievement. The laboratory design test was examined closely along with the present field meth...

J. L. Melancon S. C. Shah

1973-01-01

353

[Allergy towards bone cement].  

PubMed

Bone cements based on polymethylmethacrylate are typically used for fixation of artificial joints. Intolerance reactions to endoprostheses not explained by infection or mechanical failure may lead to allergological diagnostics, which mostly focuses on metal allergy. However, also bone cement components may provoke hypersensitivity reactions leading to eczema, implant loosening, or fistula formation. Elicitors of such reactions encompass acrylates and additives such as benzoyl peroxide, N,N-dimethyl-p-toluidine, hydroquinone, or antibiotics (particularly gentamicin). Upon repeated contact with bone cement components, e.g., acrylate monomers, also in medical personnel occasionally hand eczema or even asthma may develop. Therefore, in the case of suspected hypersensitivity reactions to arthroplasty, the allergological diagnostics should include bone cement components. PMID:16865384

Thomas, P; Schuh, A; Summer, B; Mazoochian, F; Thomsen, M

2006-09-01

354

Fluid-bed process for SYNROC production  

SciTech Connect

SYNROC is a titanate-based ceramic waste developed for the immobilization of high-level nuclear reactor waste. Lawrence Livermore National Laboratory (LLNL) has investigated a fluid-bed technique for the large-scale production of SYNROC precursor powders. Making SYNROC in a fluid bed permits slurry drying, calcination and reduction-oxidation reactions to be carried out in a single unit. We present the results of SYNROC fluid-bed studies from two fluid-bed units 10 cm in diameter: an internally heated fluid-bed unit developed by Exxon Idaho and an externally heated unit constructed at LLNL. Bed operation over a range of temperatures, feed rates, fluidizing rates, and redox conditions indicate that SYNROC powders of a high density and a uniform particle size can be produced. These powders facilitate the densification step and yield dense ceramics (greater than 95% theoretical density) with well-developed phases and low leaching rates.

Ackerman, F.J.; Grens, J.Z.; Ryerson, F.J.; Hoenig, C.L.; Bazan, F.; Peters, P.E.; Smith, R.; Campbell, J.H.

1983-03-30

355

A DESIGN CASE STUDY: INTEGRATED PRODUCT AND PROCESS MANAGEMENT  

Microsoft Academic Search

Traditional design practices in construction indicate that most of the emphasis appears to be on product design. This may be the result of the traditional process of design-bid-build, where the design team pre-defines means and methods to the contracting team. In contrast, lean design incorporates not only product design, but also process design. Process design is commonly one of the

Roberto Arbulu; Javier Soto

356

Solvent degradation products in nuclear fuel processing solvents  

Microsoft Academic Search

The Savannah River Plant uses a modified Purex process to recover enriched uranium and separate fission products. This process uses 7.5% tri-n-butyl phosphate (TBP) dissolved in normal paraffin hydrocarbons for the solvent extraction of a nitric acid solution containing the materials to be separated. Periodic problems in product decontamination result from solvent degradation. A study to improve process efficiency has

Shook; H. E. Jr

1988-01-01

357

Barnacle cement: An etchant for stainless steel 316L?  

Microsoft Academic Search

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

R. Sangeetha; R. Kumar; M. Doble; R. Venkatesan

2010-01-01

358

Modelling of leaching in pure cement paste and mortar  

Microsoft Academic Search

The leaching of cement-based materials is analysed through experimental and numerical results. From the experimental point of view, the leaching processes of a pure cement paste and a mortar are characterised by the degraded depths and the cumulative amount of leached calcium at different times. From the mathematical point of view, the leaching is modelled with the mass balance equation

Marc Mainguy; Claire Tognazzi; Jean-Michel Torrenti; Frédéric Adenot

2000-01-01

359

Accelerated carbonation of Friedel's salt in calcium aluminate cement paste  

Microsoft Academic Search

The stability of Friedel's salt with respect to carbonation has been studied in calcium aluminate cement (CAC) pastes containing NaCl (3% of Cl? by weight of cement). Carbonation was carried out on a powdered sample in flowing 5% CO2 gas at 65% relative humidity to accelerate the process. At an intermediate carbonation step, a part of the sample was washed

S. Goñi; A. Guerrero

2003-01-01

360

Process for production desulfurized of synthesis gas  

DOEpatents

A process for the partial oxidation of a sulfur- and silicate-containing carbonaceous fuel to produce a synthesis gas with reduced sulfur content which comprises partially oxidizing said fuel at a temperature in the range of 1900.degree.-2600.degree. F. in the presence of a temperature moderator, an oxygen-containing gas and a sulfur capture additive which comprises a calcium-containing compound portion, a sodium-containing compound portion, and a fluoride-containing compound portion to produce a synthesis gas comprising H.sub.2 and CO with a reduced sulfur content and a molten slag which comprises (1) a sulfur-containing sodium-calcium-fluoride silicate phase; and (2) a sodium-calcium sulfide phase.

Wolfenbarger, James K. (Torrance, CA) [Torrance, CA; Najjar, Mitri S. (Wappingers Falls, NY) [Wappingers Falls, NY

1993-01-01

361

Process for the production of maleic anhydride  

SciTech Connect

A process is described for the vapor phase oxidation of hydrocarbons having 4 carbon atoms to produce maleic anhydride comprising contacting the hydrocarbons with a fixed bed vanadium-phosphorus-oxygen catalyst, containing P:V in an atomic ration of 1/2 to 3:1 whereby the catalyst gradually decreases in selectivity, wherein the improvement comprises contacting the catalyst with phosphorus compound of phosphorus halide, phosphorus oxyhalide, organic phospines, organic phosphites, organic phosphates or mixtures thereof at a temperature in the range of about 0/sup 0/ to 600/sup 0/C and thereafter contacting the catalyst with a flow of stream at a temperature in the range of 300/sup 0/ to 600/sup 0/C in an amount and for a sufficient duration whereby the catalyst is regenerated.

Click, G.T.; Barone, B.J.

1986-06-24

362

A non-linear model of economic production processes  

NASA Astrophysics Data System (ADS)

We present a new two phase model of economic production processes which is a non-linear dynamical version of von Neumann's neoclassical model of production, including a market price-setting phase as well as a production phase. The rate of an economic production process is observed, for the first time, to depend on the minimum of its input supplies. This creates highly non-linear supply and demand dynamics. By numerical simulation, production networks are shown to become unstable when the ratio of different products to total processes increases. This provides some insight into observed stability of competitive capitalist economies in comparison to monopolistic economies. Capitalist economies are also shown to have low unemployment.

Ponzi, A.; Yasutomi, A.; Kaneko, K.

2003-06-01

363

Land Rover uses Jack and Robcad to perfect production processes  

Microsoft Academic Search

Reviews the use of simulation tools for process design at Land Rover. Outlines new applications of Jack and Robcad tools to the development of the Freelander production process. Describes how simulation reduces time-to-insight. Explains the potential for virtual reality tools in process development.

Anna Kochan

1998-01-01

364

48 CFR 870.111-5 - Frozen processed food products.  

Code of Federal Regulations, 2013 CFR

...processed food products that contain meat, poultry or a significant...be processed or prepared in plants operating under the supervision...with USDA regulations governing meat, poultry, or egg inspection...be processed or prepared in plants operated under the...

2013-10-01

365

Optimizing software product integrity through life-cycle process integration  

Microsoft Academic Search

Managed and optimized—these are the names for the levels 4 and 5 of the Capability Maturity Model (CMM) respectively. With that the Software Engineering Institute (SEI) pays tribute to the fact that, after the process has been defined, higher process maturity, and with that higher product maturity, can only be achieved by improving and optimizing the life-cycle process itself. In

Barry Boehm; Alexander Egyed

1999-01-01

366

A Research on Green Product Design Process and Evaluation  

Microsoft Academic Search

The paper analyses the concept properties, procedures and principles of green product design, develops the principles and evaluating indicators, and discusses a green design scheme evaluation process research based on the indicator system. The paper proposes a positive evaluation of the design process and model, realizes the combination of the summative assessment, stage assessment, diagnostic evaluation and dynamic optimization process.

Li Zhuo; Yan Shengxue

2010-01-01

367

New product development process and total quality management  

Microsoft Academic Search

Summary form only given. The total quality management (TQM) paradigm provides an approach for achieving continuous improvement. Critical for this are (i) a good understanding of the new product development (NPD) process and (ii) defining suitable metrics to assess the NPD process. Once this is done, data needs to be collected to assess the quality of the NPD process in

A. Bellary; D. N. P. Murthy

1999-01-01

368

Next generation enhancement of cements by the addition of industrial wastes and subsequent treatment with supercritical CO{sub 2}  

SciTech Connect

The natural curing reactions which occur in a standard portland cement involve the formation of portlandite, Ca(OH){sub 2}, and calcium silicate hydrates, CSH. Over time, the cured cement abstracts carbon dioxide, CO{sub 2}, from the air, converting the portlandite and CSH to calcium carbonate, CaCO{sub 3}. It turns out, however, that this secondary conversion results in the blockage and/or closure of pores, drastically slowing the reaction rate with time. By exposing a portland cement to supercritical CO{sub 2} (SCCO{sub 2}), it is found that the carbonation reaction can be greatly accelerated. This acceleration is due to (1) the ability of the supercritical fluid to penetrate into the pores of the cement, providing continuous availability of fresh reactant, in hyper-stoichiometric concentrations; and (2) the solubility of the reaction product in the supercritical fluid, facilitating its removal. By accelerating the natural aging reactions, a chemically stable product is formed having reduced porosity, permeability and pH, while at the same time significantly enhancing the mechanical strength. The supercritical CO{sub 2} treatment process also removes a majority of the hydrogenous material from the cement, and sequesters large amounts of carbon dioxide, permanently removing it from the environment. The authors describe the general features of supercritical fluids, as well as the application of these fluids to the treatment of cements containing industrial waste. Some of the issues concerning the economic feasibility of industrial scale-up will be addressed. Finally, some initial results of physical property measurements made on portland cements before and after supercritical fluid CO{sub 2} treatment will be presented.

Taylor, C.M.V.; Rubin, J.B.; Carey, J.W. [Los Alamos National Lab., NM (United States); Jones, R. [Materials Technology Ltd., Reno, NV (United States); Baglin, F.G. [Univ. of Nevada, Reno, NV (United States). Chemical Physics Program

1997-09-01

369

A Pulse-Type Baghouse Designed for Use on a Cement Kiln Clinker Cooler  

Microsoft Academic Search

At Alpena, Ml, the Cement Division of National Gypsum Company operates nine kilns producing 2.5 million tons of cement per year. Most of the finished cement is shipped on our own fleet of six vessels to thirteen terminals along the Great Lakes. To control air sources in our division, we have over three hundred baghouse installations on various processes including

Walter W. Dowd; Darrell L. Bump

1979-01-01

370

Technology for the product and process data base  

NASA Technical Reports Server (NTRS)

The computerized product and process data base is increasingly recognized to be the cornerstone component of an overall system aimed at the integrated automation of the industrial processes of a given company or enterprise. The technology needed to support these more effective computer integrated design and manufacturing methods, especially the concept of 3-D computer-sensible product definitions rather than engineering drawings, is not fully available and rationalized. Progress is being made, however, in bridging this technology gap with concentration on the modeling of sophisticated information and data structures, high-performance interactive user interfaces and comprehensive tools for managing the resulting computerized product definition and process data base.

Barnes, R. D.

1984-01-01

371

Novel cationic-modified salep as an efficient flocculating agent for settling of cement slurries.  

PubMed

A new cationic flocculant was synthesized by graft copolymerization of acrylamide (AM) and 3-(methacryloylamino)propyl]trimethylammonium chloride (MAPTAC) onto salep using free radical polymerization initiated by ammonium persulfate (APS) to produce cationic salep [S-g-P(AM-co-MAPTAC)]. Reaction parameters (monomers/salep ratio, concentration of reactants, MAPTAC/AM ratio, and APS) were optimized using a full factorial experimental design to obtain the highest settling rate for cement suspensions. The best performing product was characterized by gel permeation chromatography (GPC), FTIR, (1)H NMR spectroscopy, and thermogravimetric analysis (TGA). The resulted cationic flocculant may be introduced as a promising candidate for the green production of asbestos-free fiber cement products by Hatschek process. PMID:23499090

Pourjavadi, Ali; Fakoorpoor, Seyed Mahmoud; Hosseini, Seyed Hassan

2013-04-01

372

Upstream processes in antibody production: evaluation of critical parameters.  

PubMed

The demand for monoclonal antibody for therapeutic and diagnostic applications is rising constantly which puts up a need to bring down the cost of its production. In this context it becomes a prerequisite to improve the efficiency of the existing processes used for monoclonal antibody production. This review describes various upstream processes used for monoclonal antibody production and evaluates critical parameters and efforts which are being made to enhance the efficiency of the process. The upstream technology has tremendously been upgraded from host cells used for manufacturing to bioreactors type and capacity. The host cells used range from microbial, mammalian to plant cells with mammalian cells dominating the scenario. Disposable bioreactors are being promoted for small scale production due to easy adaptation to process validation and flexibility, though they are limited by the scale of production. In this respect Wave bioreactors for suspension culture have been introduced recently. A novel bioreactor for immobilized cells is described which permits an economical and easy alternative to hollow fiber bioreactor at lab scale production. Modification of the cellular machinery to alter their metabolic characteristics has further added to robustness of cells and perks up cell specific productivity. The process parameters including feeding strategies and environmental parameters are being improved and efforts to validate them to get reproducible results are becoming a trend. Online monitoring of the process and product characterization is increasingly gaining importance. In total the advancement of upstream processes have led to the increase in volumetric productivity by 100-fold over last decade and make the monoclonal antibody production more economical and realistic option for therapeutic applications. PMID:17920803

Jain, Era; Kumar, Ashok

2008-01-01

373

Differential Scanning Calorimetry Study of Ordinary Portland Cements Mixed with fly Ash and Slag  

NASA Astrophysics Data System (ADS)

The study of the thermal behavior (DSC) of hydration products in ordinary Portland cement (OPC), as a function of water cement ratios (W/C) (0.2, 0.25, ... 0.4), and the partial substitution of (35 % fly ash), (35 % slag) and (35 % fly ash + 35 % slag) to the OPC system by weight separately was carried out. It was found that the additive materials (pozzlans) increase its durability when added to the OPC. The most important effects in the cement paste microstructure are the changes in pore structure produced by the reduction in the grain size caused by the pozzlanic reactions. The study revealed that the changes in all the thermal parameters depend on the variation of W/C ratios. The systematic changes in the activation energy through all systems occur at (0.3) W/C in the phase (C-H) and (0.35) W/C in the phase (C-S-H). This means that at these ratios of W/C the two phases (C-H) and (C-S-H) further accelerated the process of cement hydration reactions, and at the same time the addition to OPC system may provide enough space for hydration products to be distributed uniformly.

Al-Salami, A. E.; Ahmed, M. A.; Al-Hajry, A.; Taha, S.

2005-03-01

374

Global warming impact on the cement and aggregates industries  

SciTech Connect

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.

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

1994-06-01

375

Production Process of a New Cellulosic Fiber with Antimicrobial Properties  

Microsoft Academic Search

The Lyocell process (system: cellulose-water-N-methylmorpholine oxide) of Zimmer AG offers special advantages for the production of cellulose fibers. The process excels by dissolving the most diverse cellulose types as these are optimally adjusted to the process by applying different pretreatment methods. Based on this stable process, Zimmer AG’s objective is to impart to the Lyocell fiber additional value to improve

S. Zikeli

2006-01-01

376

Vaccine production: upstream processing with adherent or suspension cell lines.  

PubMed

The production of viral vaccines in cell culture can be accomplished with primary, diploid, or continuous (transformed) cell lines. Each cell line, each virus type, and each vaccine preparation require the specific design of upstream and downstream processing. Media have to be selected as well as production vessels, cultivation conditions, and modes of operation. Many viruses only replicate to high titers in adherently growing cells, but similar to processes established for recombinant protein production, an increasing number of suspension cell lines is being evaluated for future use. Here, we describe key issues to be considered for the establishment of large-scale virus production in bioreactors. As an example upstream processing of cell culture-derived influenza virus production is described in more detail for adherently growing and for suspension cells. In particular, use of serum-containing, serum-free, and chemically defined media as well as choice of cultivation vessel are considered. PMID:24297427

Genzel, Yvonne; Rödig, Jana; Rapp, Erdmann; Reichl, Udo

2014-01-01

377

Scrounge data processing film products for the thematic mapper  

NASA Technical Reports Server (NTRS)

Information on the format of the film product and type of film used for the LANDSAT-4 scrounge processed thematic mapper data is presented. Image gray scale, annotation field, and general layout are described.

1983-01-01

378

Production and Processing of Cu-Cr-Nb Alloys.  

National Technical Information Service (NTIS)

A new Cu-based alloy possessing high strength, high conductivity, and good stability at elevated temperatures was recently produced. This paper details the melting of the master alloys, production of rapidly solidified ribbon, and processing of the ribbon...

D. L. Ellis G. M. Michal N. W. Orth

1990-01-01

379

GREENING STANDARDS FOR GREEN STRUCTURES: PROCESS AND PRODUCTS  

EPA Science Inventory

The goal of this project is to provide a mechanism that equips consumers with the means for encouraging the homebuilding industry—designers, homebuilders, retail suppliers—to use environmentally preferable products (ENP) and processes in the design and con...

380

Processing of Vietnamese Essential Oils and Related Natural Products.  

National Technical Information Service (NTIS)

A project document on processing of Vietnamese Essential Oils and related natural products was drawn up between the United Nations Industrial Development Organization (UNIDO) and the Socialist Republic of Vietnam to develop an essential oils industry by u...

R. Gupta

1990-01-01

381

Foamed cement: A second generation. [Foamed cement slurries  

Microsoft Academic Search

Advanced technology in design and implementation of stable foamed cement systems now offers new solutions to critical oil-field cementing problems well beyond the original utility of lightweight slurries in reducing hydrostatic pressure across fracture-sensitive zones. Implications of new high-performance foamed cement capabilities are discussed for specialized applications such as thermal recovery, deep cementing in a narrow annular gap, lost-circulation control

Loeffler

1984-01-01

382

Modelling and control of process industry batch production systems  

Microsoft Academic Search

Many models of process industry batch production systems are of a continuous- time\\/discrete-event (CT\\/DE) nature: physical processes are modelled using CT specifications, operating procedures are modelled using DE specifications. For scheduling of batch production systems, special purpose tools are available. The Chi language is a CT\\/DE language with high level DE language elements. This makes it possible to model physical

D. A. van Beek; A. van den Ham; J. E. Rooda

2003-01-01

383

Recombinant protein production and insect cell culture and process  

NASA Technical Reports Server (NTRS)

A process has been developed for recombinant production of selected polypeptides using transformed insect cells cultured in a horizontally rotating culture vessel modulated to create low shear conditions. A metabolically transformed insect cell line is produced using the culture procedure regardless of genetic transformation. The recombinant polypeptide can be produced by an alternative process using the cultured insect cells as host for a virus encoding the described polypeptide such as baculovirus. The insect cells can also be a host for viral production.

Spaulding, Glenn (inventor); Prewett, Tacey (inventor); Goodwin, Thomas (inventor); Francis, Karen (inventor); Andrews, Angela (inventor); Oconnor, Kim (inventor)

1993-01-01

384

Recombinant Protein Production and Insect Cell Culture and Process  

NASA Technical Reports Server (NTRS)

A process has been developed for recombinant production of selected polypeptides using transformed insect cells cultured in a horizontally rotating culture vessel modulated to create low shear conditions. A metabolically transformed insect cell line is produced using the culture procedure regardless of genetic transformation. The recombinant polypeptide can be produced by an alternative process using virtually infected or stably transformed insect cells containing a gene encoding the described polypeptide. The insect cells can also be a host for viral production.

Spaulding, Glenn F. (Inventor); Goodwin, Thomas J. (Inventor); OConnor, Kim C. (Inventor); Francis, Karen M. (Inventor); Andrews, Angela D. (Inventor); Prewett, Tracey L. (Inventor)

1997-01-01

385

Constraints Based Modeling for Innovative Product & Process Designs  

Microsoft Academic Search

An innovative, constraints based modeling (CBM) approach proved successful for product developments and process improvements.\\u000a The product developments involved specifying the chemical composition range for a set of chromium-free, high-performance consumable\\u000a electrodes intended for gas-metal arc welding (GMAW) of high-strength steels used in hull constructions while significantly\\u000a reducing energy costs. The process improvements involved selecting appropriate non-carcinogenic chemicals for a

K. Sampath

2007-01-01

386

Repeated fed-batch process for improving lovastatin production  

Microsoft Academic Search

Submerged cultivation of a high yielding strain of Aspergillus terreus DRCC 122 for the production of lovastatin in the batch process had limited success with a maximum titre of 1270 mg l?1 in 288 h and an overall volumetric productivity of 4.41 mg l?1 h?1 in a 1000 l bioreactor. A cost effective repeated fed-batch process with maltodextrin and corn

M. Sitaram Kumar; Swapan K Jana; V Senthil; V Shashanka; S. Vijay Kumar; A. K Sadhukhan

2000-01-01

387

ULTRA-LIGHTWEIGHT CEMENT  

SciTech Connect

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.

Fred Sabins

2001-10-23

388

Process for the electrothermal production of yellow phosphorus  

Microsoft Academic Search

The disclosure relates to a process for removing foreign components, especially zinc, from the product cycle during the production of yellow phosphorus inside and electrothermal furnace. To this end, the disclosure provides for molten ferrophosphorus and a calcium metasilicate slag and also a dust-containing gas mixture consisting essentially of carbon monoxide and phosphorus in vapor form to be taken from

K. Rottgen; H. Diskowski; J. Stendel

1985-01-01

389

Sustainable Production Process of Biological Mineral Feed Additives  

Microsoft Academic Search

Problem statement: This study discussed the problem of accumulation of Zn and Cu in the topsoil as a result of application of mineral feed additives that possess low bioavailability in anima l diet. The review considered the production process of mineral feed additives in which a product supplies microelements in highly bioavailable form. Enrichment of natural biomass of edible microalgae

Katarzyna Chojnacka; Poland Wroclaw; Marjana Simonic

2009-01-01

390

A Macro Process Model for Product Innovation Using TRIZ  

Microsoft Academic Search

The process of product innovation consists of three stages, which are fuzzy front end (FFE), new product development (NPD) and commercialization (COM). Theory of inventive problem solving (TRIZ) is a systematic approach to find innovative solutions for technical problems. The patterns and lines of TRIZ are applied to FFE to produce new ideas. The principles, standard solutions and effects of

Tan Runhua

391

Outer Product Expansions and Their Uses in Digital Image Processing  

Microsoft Academic Search

This paper is intended as a tutorial review of certain digital image processing transform techniques utilizing the notion of outer product expansions. Examples from Fourier, Walsh, Haar, and other well known transforms are reviewed in the notation of matrix-vector outer products; and implementation of the singular value decomposition (SVD) of large sized images is presented. The use of the SVD

Harry C. Andrews; Claude L. Patterson III

1976-01-01

392

Benzene distribution in product streams from in-tank processing  

Microsoft Academic Search

Benzene is the major product of radiolytic decomposition of tetraphenylborate salts during in-tank salt decontamination. Its production rate has been measured at the Savannah River Laboratory (SR) and at the University of Florida under various conditions of importance to the in-tank process. Recent work has been concerned with the extent of decomposition for long storage periods, and the composition of

1987-01-01

393

Early erosion of dental cements.  

PubMed

The disintegration in water of various unset glass ionomer cements, a polycarboxylate and a zinc phosphate cement was measured gravimetrically after exposure of the cements to a constant water jet. The test gave reproducible results with significant variations between the various types and brands of cements. For zinc phosphate and polycarboxylate cements, no weight loss was observed in the period from 4 to 8 min after commencement of mixing. All the glass ionomer cements showed a significant loss of weight at 4 min and a somewhat reduced weight loss at 6 min after start of mixing. Two cements, a filling and a luting material, showed reduced weight when exposed to a water jet even 8 min after start of mixing. The early erosion as recorded in the present study conforms with the setting of the glass ionomer cements. PMID:6597538

Oilo, G

1984-12-01

394

Expansive Cements and Their Use.  

National Technical Information Service (NTIS)

The primary purpose of shrinkage-compensating expansive cement concrete is to minimize cracking in concrete pavements and structures caused by drying shrinkage. The paper reviews the various types of expansive cements and their properties. The expansive m...

G. C. Hoff

1972-01-01

395

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

PubMed

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 CO?-intensive. But most CO? 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. PMID:22573713

Thomanetz, Erwin

2012-04-01

396

Hydrothermal cement/metal interfaces  

SciTech Connect

The authors investigated the adherence of two cementitious materials, calcium phosphate cement (CPC) and silica flour-filled class G cement (CGC), to metal substrates, such as cold-rolled steel (CRS), stainless steel (SS), electroplated zinc-coated steel (EZS), and zinc phosphate-coated steel (ZPS) after autoclaving at 200 C. In CPC/metal joints, the {gamma}-AlOOH phase, which segregated from the hydroxyapatite phase of the CPC matrix, was preferentially precipitated on the CRS and SS surfaces and also mixed with the reaction products formed at the interfaces between CPC and EZS or ZPS. Precipitation of {gamma}-AlOOH caused the formation of a weak boundary layer at the interfacial transition zones, thereby resulting in a low shear-bond strength. Although CGC accelerated the rate of corrosion of CRS and SS surfaces, the growth of Fe{sub 2}O{sub 3} clusters, formed as the corrosion products of metals at interfaces, aided the anchoring effect of xonotlite crystals as the major phase of CGC matrix, thereby conferring a high shear-bond strength. The EZS and ZPS surfaces were susceptible to alkali dissolution caused by the attack of the high-pH interstitial fluid of CGC pastes to the Zn and zinc phosphate coatings. Thus, the bond strengths of the CGC/EZS and /ZPS joints were lower than those of the joints made with CRS and SS.

Sugama, Toshifumi [Brookhaven National Lab., Upton, NY (United States); Baldwin, S. [Worcester Polytechnic Inst., MA (United States). Dept. of Chemistry

1996-01-01

397

THE USE OF STATISTICAL PROCESS CONTROL AND DESIGN OF EXPERIMENTS IN PRODUCT AND PROCESS IMPROVEMENT  

Microsoft Academic Search

Quality and productivity improvement has become an essential element of the overall strategic plan for most organizations. This has sparked renewed interest in statistical methods for quality improvement. This paper reviews some recent developments in statistical methodology that have application in product and process improvement, concentrating on statistical process control and design of experiments. Some directions for future research are

DOUGLAS C. MONTGOMERY

1992-01-01

398

Product data quality validation system for product development processes in high-tech industry  

Microsoft Academic Search

Among various product data, 3D CAD data plays a key role in current product design and manufacturing processes including industrial design, detail design, CAE, inspection, mould-making, production, and so on. If 3D CAD data has geometrical or topological errors by user mistakes or modelling software bugs and those errors are not cleaned by the data creator in an early stage,

Seokbae Son; Sangwook Na; Kukjin Kim

2011-01-01

399

Method for processing wastes resulting from production of phosphorus  

SciTech Connect

The method comprises processing slime and off-gases resulting from the production of phosphorus with an aqueous solution of copper sulphate having a concentration of from 15 to 50% at a temperature within the range of from 20* to 80* C. As a result, two products are obtained, i.e., a liquid product and a solid one. The solid product containing mainly copper phosphide as well as fluorides and chlorides of alkali metals and silicon, and silicates of calcium and aluminum, is used as a modifying and refining agent for hypereutectic silumines and for the manufacture of a copper-phosphorus alloy. The liquid product containing phosphoric acid, sulphuric acid and copper sulphate is used as starting product for the preparation of a copper-containing fertilizer. The method according to the present invention makes it possible to modify the production of phosphorus so as to eliminate the formation of secondary wastes and improve the environmental control.

Alzhanov, T.M.; Bykov, V.I.; Chernogorenko, V.B.; Dmitrenko, V.V.; Ishkhanov, E.S.; Kipchakbaev, A.D.; Koverya, V.M.; Lynchak, K.A.; Markovsky, E.A.; Muchnik, S.V.; Pobortsev, M.E.; Sapian, V.G.; Sergienko, V.Y.; Vopilov, A.N.

1980-03-11

400

Production of superclean gases by cryogenic methods: process calculation  

NASA Astrophysics Data System (ADS)

Liquid and gaseous cryoproducts of high purity are required for some processes. Technically pure cryoproducts produced by air and gas separation plants do not always meet the requirements of production as regards the percentage of impurities. Low-temperature rectification is a means of additional purification of technical oxygen from residual impurities, to produce high-purity productive gas. It is interesting to establish the composition of the intermediate flow obtained in the process of separation and especially the production flow of all components (higher- and lower-boiling components and oxygen).

Budnevich, S. S.; Borzenko, E. I.

401

Image processing system performance prediction and product quality evaluation  

NASA Technical Reports Server (NTRS)

The author has identified the following significant results. A new technique for image processing system performance prediction and product quality evaluation was developed. It was entirely objective, quantitative, and general, and should prove useful in system design and quality control. The technique and its application to determination of quality control procedures for the Earth Resources Technology Satellite NASA Data Processing Facility are described.

Stein, E. K.; Hammill, H. B. (principal investigators)

1976-01-01

402

State estimation of a Uricase production process with Candida Utilis  

Microsoft Academic Search

The present work discusses the implementation of a Kalman filtering procedure in a state estimation of a batch Uricase production process with Candida Utilis. An unstructured model of the process is used for the estimation procedure. The observability is thoroughly investigated and a Kalman filter is applied afterwards as a powerful and precise state estimation tool. The estimates in all

L. Ganovski; M. Bliznakova; T. Patarinska

1999-01-01

403

Integrated PV-thermal panel and process for production  

Microsoft Academic Search

A process is described for production of integrated photovoltaic-thermal panels, the preferred process including the following chemical vapor depositions, in air, and the following work stations: (a) copper oxide station, whereby sheet copper, Cu, is cleaned and a layer of copper oxide, CuO, is formed thereon by heating the copper in air or steam, (b) silica station, whereby silicic acid,

Jarnagin

1986-01-01

404

Auditing improvements in a product delivery process (AIPDP)  

Microsoft Academic Search

Purpose – The purpose of this paper is to assess the appropriateness of using the 12 previously published material flow simplicity rules (SRs) to shape the successful design and implementation of improvements in a casting company product delivery process (PDP). Design\\/methodology\\/approach – The business process improvement (BPI) project described in this case study was actively supported by the UK knowledge

Paul Childerhouse; Andrew Thomas; Gareth Phillips; Denis R. Towill

2010-01-01

405

Improving preanalytic processes using the principles of lean production (Toyota Production System).  

PubMed

The basic technologies used in preanalytic processes for chemistry tests have been mature for a long time, and improvements in preanalytic processes have lagged behind improvements in analytic and postanalytic processes. We describe our successful efforts to improve chemistry test turnaround time from a central laboratory by improving preanalytic processes, using existing resources and the principles of lean production. Our goal is to report 80% of chemistry tests in less than 1 hour and to no longer recognize a distinction between expedited and routine testing. We used principles of lean production (the Toyota Production System) to redesign preanalytic processes. The redesigned preanalytic process has fewer steps and uses 1-piece flow to move blood samples through the accessioning, centrifugation, and aliquoting processes. Median preanalytic processing time was reduced from 29 to 19 minutes, and the laboratory met the goal of reporting 80% of chemistry results in less than 1 hour for 11 consecutive months. PMID:16482987

Persoon, Thomas J; Zaleski, Sue; Frerichs, Janice

2006-01-01

406

Hydration Characteristics of Metakaolin Admixtured Cement using DTA, XRD and SEM Techniques  

NASA Astrophysics Data System (ADS)

The paper aims to investigate hydration and pozzolanic reaction in Portland cement paste with different replacement percentages (0%, 10%, 20% and 30%) of metakaolin. The compressive strength of the metakaolin admixtured cement was measured at 1 day, 1 week and 4 weeks. The compressive strength developments of the metakaolin admixtured cement are compared with Portland cement. It is found that metakaolin contributes significantly to strength development as an accelerating admixture for Portland cement. The pozzolanic reactions and the reaction products were determined by DTA, XRD and SEM.

Govindarajan, D.; Gopalakrishnan, R.

2008-04-01

407

Image processing and products for the Magellan mission to Venus  

NASA Technical Reports Server (NTRS)

The Magellan mission to Venus is providing planetary scientists with massive amounts of new data about the surface geology of Venus. Digital image processing is an integral part of the ground data system that provides data products to the investigators. The mosaicking of synthetic aperture radar (SAR) image data from the spacecraft is being performed at JPL's Multimission Image Processing Laboratory (MIPL). MIPL hosts and supports the Image Data Processing Subsystem (IDPS), which was developed in a VAXcluster environment of hardware and software that includes optical disk jukeboxes and the TAE-VICAR (Transportable Applications Executive-Video Image Communication and Retrieval) system. The IDPS is being used by processing analysts of the Image Data Processing Team to produce the Magellan image data products. Various aspects of the image processing procedure are discussed.

Clark, Jerry; Alexander, Doug; Andres, Paul; Lewicki, Scott; Mcauley, Myche

1992-01-01

408

Analytical calculation of heavy quarkonia production processes in computer  

NASA Astrophysics Data System (ADS)

This report is devoted to the analytical calculation of heavy quarkonia production processes in modern experiments such as LHC, B-factories and superB-factories in computer. Theoretical description of heavy quarkonia is based on the factorization theorem. This theorem leads to special structure of the production amplitudes which can be used to develop computer algorithm which calculates these amplitudes automatically. This report is devoted to the description of this algorithm. As an example of its application we present the results of the calculation of double charmonia production in bottomonia decays and inclusive the ?cJ mesons production in pp-collisions.

Braguta, V. V.; Likhoded, A. K.; Luchinsky, A. V.; Poslavsky, S. V.

2014-06-01

409

Influence of the radiopacifier in an acrylic bone cement on its mechanical, thermal, and physical properties: barium sulfate-containing cement versus iodine-containing cement.  

PubMed

In all acrylic bone cement formulations in clinical use today, radiopacity is provided by micron-sized particles (typical mean diameter of between about 1 and 2 microm) of either BaSO(4) or ZrO(2). However, a number of research reports have highlighted the fact that these particles have deleterious effects on various properties of the cured cement. Thus, there is interest in alternative radiopacifiers. The present study focuses on one such alternative. Specifically, a cement that contains covalently bound iodine in the powder (herein designated the I-cement) was compared with a commercially available cement of comparable composition (C-ment3), in which radiopacity is provided by BaSO(4) particles (this cement is herein designated the B-cement), on the basis of the strength (sigma(b)), modulus (E(b)), and work-to-fracture (U(b)), under four-point bending, plane-strain fracture toughness (K(IC)), Weibull mean fatigue life, N(WM) (fatigue conditions: +/-15 MPa; 2 Hz), activation energy (Q), and frequency factor (ln Z) for the cement polymerization process (both determined by using differential scanning calorimetry at heating rates of 5, 10, 15, and 20 K min(-1)), and the diffusion coefficient for the absorption of phosphate-buffered saline at 37 degrees C (D). For the B-cement, the values of sigma(b), E(b), U(b), K(IC), N(WM), Q, ln Z, and D were 53 +/- 3 MPa, 3000 +/- 120 MPa, 108 +/- 15 kJ m(-3), 1.67 +/- 0.02 MPa check mark m, 7197 cycles, 243 +/- 17 kJ mol(-1), 87 +/- 6, and (3.15 +/- 0.94) x 10(-12) m(2) s(-1), respectively. For the I-cement, the corresponding values were 58 +/- 5 MPa, 2790 +/- 140 MPa, 118 +/- 45 kJ m(-3), 1.73 +/- 0.11 MPa check mark m, 5520 cycles, 267 +/- 19 kJ mol(-1), 95 +/- 9, and (3.83 +/- 0.25) x 10(-12) m(2) s(-1). For each of the properties of the fully cured cement, except for the rate constant of the polymerization reaction, at 37 degrees C (k'), as estimated from the Q and ln Z results, there is no statistically significant difference between the two cements. k' for the I-cement was about a third that for the B-cement, suggesting that the former cement has a higher thermal stability. The influence of various characteristics of the starting powder (mean particle size, particle size distribution, and morphology) on the properties of the cured cements appears to be complex. When all the present results are considered, there is a clear indication that the I-cement is a viable candidate cement for use in cemented arthroplasties in place of the B-cement. PMID:15786447

Lewis, Gladius; van Hooy-Corstjens, Catharina S J; Bhattaram, Anuradha; Koole, Leo H

2005-04-01

410

Magnesium phosphate glass cements with ceramic-type properties  

DOEpatents

Rapid setting magnesium phosphate (Mg glass) cementitious materials consisting of magnesium phosphate cement paste, polyborax and water-saturated aggregate exhibiting rapid setting and high early strength characteristics. The magnesium glass cement is prepared from a cation-leachable powder and a bivalent metallic ion-accepting liquid such as an aqueous solution of diammonium phosphate and ammonium polyphosphate. The cation-leachable powder includes a mixture of two different magnesium oxide powders processed and sized differently which when mixed with the bivalent metallic ion-accepting liquid provides the magnesium glass cement consisting primarily of magnesium ortho phosphate tetrahydrate, with magnesium hydroxide and magnesium ammonium phosphate hexahydrate also present. The polyborax serves as a set-retarder. The resulting magnesium mono- and polyphosphate cements are particularly suitable for use as a cementing matrix in rapid repair systems for deteriorated concrete structures as well as construction materials and surface coatings for fireproof structures.

Sugama, Toshifumi (Mastic Beach, NY); Kukacka, Lawrence E. (Port Jefferson, NY)

1984-03-13

411

Magnesium-phosphate-glass cements with ceramic-type properties  

DOEpatents

Rapid setting magnesium phosphate (Mg glass) cementitious materials consisting of magnesium phosphate cement paste, polyborax and water-saturated aggregate, exhibits rapid setting and high early strength characteristics. The magnesium glass cement is prepared from a cation-leachable powder and a bivalent metallic ion-accepting liquid such as an aqueous solution of diammonium phosphate and ammonium polyphosphate. The cation-leachable powder includes a mixture of two different magnesium oxide powders processed and sized differently which when mixed with the bivalent metallic ion-accepting liquid provides the magnesium glass cement consisting primarily of magnesium ortho phosphate tetrahydrate, with magnesium hydroxide and magnesium ammonium phosphate hexahydrate also present. The polyborax serves as a set-retarder. The resulting magnesium mono- and polyphosphate cements are particularly suitable for use as a cementing matrix in rapid repair systems for deteriorated concrete structures as well as construction materials and surface coatings for fireproof structures.

Sugama, T.; Kukacka, L.E.

1982-09-23

412

Recent advances in lactic acid production by microbial fermentation processes.  

PubMed

Fermentative production of optically pure lactic acid has roused interest among researchers in recent years due to its high potential for applications in a wide range of fields. More specifically, the sharp increase in manufacturing of biodegradable polylactic acid (PLA) materials, green alternatives to petroleum-derived plastics, has significantly increased the global interest in lactic acid production. However, higher production costs have hindered the large-scale application of PLA because of the high price of lactic acid. Therefore, reduction of lactic acid production cost through utilization of inexpensive substrates and improvement of lactic acid production and productivity has become an important goal. Various methods have been employed for enhanced lactic acid production, including several bioprocess techniques facilitated by wild-type and/or engineered microbes. In this review, we will discuss lactic acid producers with relation to their fermentation characteristics and metabolism. Inexpensive fermentative substrates, such as dairy products, food and agro-industrial wastes, glycerol, and algal biomass alternatives to costly pure sugars and food crops are introduced. The operational modes and fermentation methods that have been recently reported to improve lactic acid production in terms of concentrations, yields, and productivities are summarized and compared. High cell density fermentation through immobilization and cell-recycling techniques are also addressed. Finally, advances in recovery processes and concluding remarks on the future outlook of lactic acid production are presented. PMID:23624242

Abdel-Rahman, Mohamed Ali; Tashiro, Yukihiro; Sonomoto, Kenji

2013-11-01

413

NCHRP Web-only Document 167: Statistical Modeling of Cement Heat of Hydration Using Phase and Fineness Variables.  

National Technical Information Service (NTIS)

The heat of hydration of hydraulic cements results from the complex sets of phase dissolution and precipitation activity accompanying the addition of water to a cement. This process generates heat, as well as an increased potential for thermal cracking in...

H. Azari

2010-01-01

414

Spectroscopic investigation of Ni speciation in hardened cement paste.  

PubMed

Cement-based materials play an important role in multi-barrier concepts developed worldwide for the safe disposal of hazardous and radioactive wastes. Cement is used to condition and stabilize the waste materials and to construct the engineered barrier systems (container, backfill, and liner materials) of repositories for radioactive waste. In this study, Ni uptake by hardened cement paste has been investigated with the aim of improving our understanding of the immobilization process of heavy metals in cement on the molecular level. X-ray absorption spectroscopy (XAS) coupled with diffuse reflectance spectroscopy (DRS) techniques were used to determine the local environment of Ni in cement systems. The Ni-doped samples were prepared at two different water/cement ratios (0.4, 1.3) and different hydration times (1 hour to 1 year) using a sulfate-resisting Portland cement. The metal loadings and the metal salts added to the system were varied (50 up to 5000 mg/kg; NO3(-), SO4(2-), Cl-). The XAS study showed that for all investigated systems Ni(ll) is predominantly immobilized in a layered double hydroxide (LDH) phase, which was corroborated by DRS measurements. Only a minor extent of Ni(ll) precipitates as Ni-hydroxides (alpha-Ni(OH)2 and beta-Ni(OH)2). This finding suggests that Ni-Al LDH, rather than Ni-hydroxides, is the solubility-limiting phase in the Ni-doped cement system. PMID:16646464

Vespa, M; Dähn, R; Grolimund, D; Wieland, E; Scheidegger, A M

2006-04-01

415

Evaluate cement with radioactive tracers, directional gamma ray logs  

SciTech Connect

Use of radioactive tracers to evaluate hydraulic fractures has recently been extended through the use of directional gamma ray measurements. The directional gamma ray logging tool determines the azimuthal direction of gamma rays from radioactive isotope-tagged fracture proppants to estimate the fracture direction in well-controlled circumstances. The technology also provides new ways of evaluating primary and squeeze cement jobs by enhancing information from directional gamma ray data with advanced image processing techniques. By tagging the cement with a uniform quantity per unit volume of radioactivity, different levels of gamma ray log response must be attributed to variances in cement quality. Cement evaluation with tracers can help detect: thin cement sheaths; light-weight or low compressive strength cements where the acoustic impedance is near that of water; gas cut cement where the acoustic signal is attenuated; wells with microannulus that cannot be pressured to obtain valid log data; poor casing centralization; and multiple cement stage placement. The paper describes the logging tool, operational procedures, and a log example.

NONE

1996-07-01

416

Effect of the addition of ultrafine cement and short fiber reinforcement on shrinkage, rheological and mechanical properties of Portland cement pastes  

Microsoft Academic Search

The packing density of a powder can be improved by adding a fine powder to a coarse one. This conventional technique, frequently used in ceramic production, also can be applied to optimise the properties of cementitious binders, especially for the production of high performance concrete. In this paper the effect of mixing ultrafine cement and normal grain sized Portland cement

J. Kaufmann; F. Winnefeld; D. Hesselbarth

2004-01-01

417

Comparative Assessment of TRU Waste Forms and Processes. Volume I. Waste Form and Process Evaluations.  

National Technical Information Service (NTIS)

This study provides an assesses seven waste forms and eight processes for immobilizing transuranic (TRU) wastes. The waste forms considered are cast cement, cold-pressed cement, FUETAP (formed under elevated temperature and pressure) cement, borosilicate ...

W. A. Ross R. O. Lokken R. P. May F. P. Roberts C. L. Timmerman

1982-01-01

418

Production of organic acids by electrodialysis/pervaporation process.  

SciTech Connect

Lactate esters produced from carbohydrates have potential markets as nontoxic replacements for halogenated and toxic solvents and as feedstocks for large-volume chemicals and polymers. Argonne National Laboratory has developed a novel process for the production of high-purity lactate esters from carbohydrates. The process uses advanced electrodialysis and pervaporation technologies to overcome major technical barriers in product separation; more specifically, the process involves cation elimination without the generation of salt waste and efficient esterification for final purification. This patented process requires little energy input, is highly efficient and selective, avoids the large volumes of salt waste produced by conventional processes, and significantly reduces manufacturing costs. The enabling membrane separation technologies make it technically and commercially feasible for lactate esters to penetrate the potential markets.

Tsai, S. P.; Datta, R.; Henry, M.; Halpern, Y.; Frank, J. R.; Energy Systems

1999-05-01

419

External sleeve cementing tool  

SciTech Connect

This patent describes a cementing tool apparatus. It comprises a tubular housing having an inner passage defined longitudinally therethrough and having a radially outer surface, the housing also having a cementing port and a longitudinal slot both disposed through a wall thereof; an outer closure sleeve slidably received about the outer surface of the housing and movable relative to the housing between an open position wherein the cementing port is uncovered by the closure sleeve and a closed position wherein the cementing port is closed by the closure sleeve; an inner operating sleeve slidably received in the housing and slidable between first and second positions relative to the housing; and mechanical interlocking means, extending through the slot and operably associated with both the operating sleeve and the closure sleeve, for mechanically transferring a closing force from the operating sleeve to the closure sleeve and thereby moving the closure sleeve to its closed position as the operating sleeve moves from its first position to its second position.

Giroux, R.L.; Brandell, J.T.

1991-08-13

420

Process and reactor design for biophotolytic hydrogen production.  

PubMed

The green alga Chlamydomonas reinhardtii has the ability to produce molecular hydrogen (H2), a clean and renewable fuel, through the biophotolysis of water under sulphur-deprived anaerobic conditions. The aim of this study was to advance the development of a practical and scalable biophotolytic H2 production process. Experiments were carried out using a purpose-built flat-plate photobioreactor, designed to facilitate green algal H2 production at the laboratory scale and equipped with a membrane-inlet mass spectrometry system to accurately measure H2 production rates in real time. The nutrient control method of sulphur deprivation was used to achieve spontaneous H2 production following algal growth. Sulphur dilution and sulphur feed techniques were used to extend algal lifetime in order to increase the duration of H2 production. The sulphur dilution technique proved effective at encouraging cyclic H2 production, resulting in alternating Chlamydomonas reinhardtii recovery and H2 production stages. The sulphur feed technique enabled photobioreactor operation in chemostat mode, resulting in a small improvement in H2 production duration. A conceptual design for a large-scale photobioreactor was proposed based on these experimental results. This photobioreactor has the capacity to enable continuous and economical H2 and biomass production using green algae. The success of these complementary approaches demonstrate that engineering advances can lead to improvements in the scalability and affordability of biophotolytic H2 production, giving increased confidence that H2 can fulfil its potential as a sustainable fuel of the future. PMID:23689756

Tamburic, Bojan; Dechatiwongse, Pongsathorn; Zemichael, Fessehaye W; Maitland, Geoffrey C; Hellgardt, Klaus

2013-07-14

421

Hierarchical production planning and energy modeling for food processing plants  

SciTech Connect

The development of a generalized user-oriented multi-period, multi-resource production planning system for food processing plants is presented. The practical and computational aspects of the model for implementation are considered and some associated problems are solved. A distinguishing feature of this study is that the emphasis is given to the development of an operational and easy to implement framework as a managerial aid to production planning and scheduling. The procedure starts with an inter-active user-oriented program used to formulate the LP model and control food processing plant input data. This program is a link between the model formulation and plant data. Then the model is solved using a semi-commercial LP package MINOS. At this level, an optimal production plan is determined at an aggregate level. The production planning problem solution is very important and a necessary pre-requisite to the consideration of scheduling, design and/or energy modeling procedures. Examples are given in this study, using a fully integrated meat processing plant. Finally, the development of an energy utilization model for a food processing plant is described. The model is used to predict the time-of-day energy utilization of major processes in a meat processing plant.

Shah, S.A.

1984-01-01

422

Soluble microbial products from water biological treatment process: a review.  

PubMed

The relationship between soluble microbial products (SMPs) and extracellular polymeric substances is described, and the characteristics of SMPs in the biological wastewater treatment process, including molecular weight distribution, metal-chelating property, biodegradability, biotoxicity, and membrane fouling, are investigated. The SMPs produced by autotrophs are degradable and utilizable for heterotrophs, thereby confirming the biodegradation of SMPs. Soluble microbial product models are designed through three approaches: establishment of SMP kinetic models or combination with Monod equations, incorporation of SMP generation and degradation into the unified theory raised by Laspidou and Rittmann (2002a), and introduction of the concept of SMP into activated sludge models. The effects of process parameters on SMP concentration are elaborated, based on the optimum biological treatment process operating parameters that can effectively minimize SMP production. The progress of SMP research in water biotreatment systems is presented, and suggestions for future studies are made. PMID:24734470

Kang, Jia; Du, Gang; Gao, Xu; Zhao, Bin; Guo, Jinsong

2014-03-01

423

Six Sigma process improvements in automotive parts production  

Microsoft Academic Search

Purpose: of this paper: In the paper is presented a Six Sigma project, undertaken within company for production automotive parts, which deals with identification and reduction of production cost in the deburring process for gravity die-castings and improvement of quality level of produced parts. Design\\/methodology\\/approach: The objectives are achieved by application of Six Sigma approach to quality improvement project in

M. Sokovi?; D. Pavleti?

424

NGNP Process Heat Applications: Hydrogen Production Accomplishments for FY2010  

SciTech Connect

This report summarizes FY10 accomplishments of the Next Generation Nuclear Plant (NGNP) Engineering Process Heat Applications group in support of hydrogen production technology development. This organization is responsible for systems needed to transfer high temperature heat from a high temperature gas-cooled reactor (HTGR) reactor (being developed by the INL NGNP Project) to electric power generation and to potential industrial applications including the production of hydrogen.

Charles V Park

2011-01-01

425

Information processing and new product success: a meta-analysis  

Microsoft Academic Search

Purpose – This paper aims to analyze and quantitatively compare existing empirical findings on the role of organizational information-processing and new product outcomes. The meta-analytic technique is used to reconcile some of the current divergent thinking on the role of organizational learning in new product success. Design\\/methodology\\/approach – The method and procedure of the meta-analysis are utilized to generalize existing

Iryna Pentina; David Strutton

2007-01-01

426

Production processes of licensed recombinant factor VIII preparations.  

PubMed

The state-of-the-art treatment for hemophilia A is replacement therapy with recombinant factor VIII (rFVIII) made possible by genetic engineering advances. Currently, there are four different products licensed and available for hemophilia A patients. All are produced by recombinant mammalian cells in large-scale fermenter cultures, purified to high purity, formulated in stable formulations and freeze dried. The first-generation products Recombinate and Kogenate (also sold as Helixate by Aventis) are characterized as full-length human factor VIII molecules and formulated using human serum albumin as a stabilizer. The second-generation product ReFacto contains an improved albumin-free sucrose formulation and incorporates advanced antiviral safety procedures in the manufacturing process. It is a truncated B region-deleted form of factor VIII (FVIII) that makes use of a nonhuman peptide linker 14 amino acids in length to connect the 80 and 90 kD subunits. The most recently licensed rFVIII product is the second-generation Kogenate product called KOGENATE Bayer/Kogenate FS, which combines the advantages of the human full-length FVIII molecule with an albumin-free, sucrose-based synthetic formulation as well as an improved viral safety profile. In this article, the manufacturing processes for each of the four different products are discussed in detail, focusing on expression systems and cell lines, culture medium, technical culture systems, purification process (including viral removal potential), and final formulation. PMID:11547361

Boedeker, B G

2001-08-01

427

Evaluation of the internal high alumina cement mortar lining of ductile cast iron pipes used in sewage transportation  

Microsoft Academic Search

High alumina cement has been used to line the interior of ductile cast iron pipes intended for sewage transportation. Defects occurring in the production line include waves, ripples, knots, strip cracks, milky layers, crack network, non uniform thickness, breakage and roughness. The effect of the grain size of sand, the water\\/cement ratio, the sand\\/cement ratio and the percent citric acid

S. A. S. El-Hemaly; H. A. M. Abdallah; M. F. Abadir; H. H. El Sersy

2008-01-01

428

Mechanics of aeolian processes: Soil erosion and dust production  

NASA Technical Reports Server (NTRS)

Aeolian (wind) processes occur as a result of atmosphere/land-surface system interactions. A thorough understanding of these processes and their physical/mechanical characterization on a global scale is essential to monitoring global change and, hence, is imperative to the fundamental goal of the Earth observing system (Eos) program. Soil erosion and dust production by wind are of consequence mainly in arid and semi arid regions which cover 36 percent of the Earth's land surface. Some recent models of dust production due to wind erosion of agricultural soils and the mechanics of wind erosion in deserts are reviewed and the difficulties of modeling the aeolian transport are discussed.

Mehrabadi, M. M.

1989-01-01

429

Mechanisms of Carbon Nanotube Production by Laser Ablation Process  

NASA Technical Reports Server (NTRS)

We will present possible mechanisms for nanotube production by laser oven process. Spectral emission of excited species during laser ablation of a composite graphite target is compared with that of laser irradiated C60 vapor. The similarities in the transient and spectral data suggest that fullerenes are intermediate precursors for nanotube formation. The confinement of the ablation products by means of a 25-mm diameter tube placed upstream of the target seems to improve the production and purity of nanotubes. Repeated laser pulses vaporize the amorphous/graphitic carbon and possibly catalyst particles, and dissociate fullerenes yielding additional feedstock for SWNT growth.

Scott, Carl D.; Arepalli, Sivaram; Nikolaev, Pavel; Smalley, Richard E.; Nocholson, Leonard S. (Technical Monitor)

2000-01-01

430

A Review on Biomass Torrefaction Process and Product Properties  

SciTech Connect

Biomass Torrefaction is gaining attention as an important preprocessing step to improve the quality of biomass in terms of physical properties and chemical composition. Torrefaction is a slow heating of biomass in an inert or reduced environment to a maximum temperature of approximately 300 C. Torrefaction can also be defined as a group of products resulting from the partially controlled and isothermal pyrolysis of biomass occurring in a temperature range of 200-280 C. Thus, the process can be called a mild pyrolysis as it occurs at the lower temperature range of the pyrolysis process. At the end of the torrefaction process, a solid uniform product with lower moisture content and higher energy content than raw biomass is produced. Most of the smoke-producing compounds and other volatiles are removed during torrefaction, which produces a final product that will have a lower mass but a higher heating value. The present review work looks into (a) torrefaction process and different products produced during the process and (b) solid torrefied material properties which include: (i) physical properties like moisture content, density, grindability, particle size distribution and particle surface area and pelletability; (ii) chemical properties like proximate and ultimate composition; and (iii) storage properties like off-gassing and spontaneous combustion.

Jaya Shankar Tumuluru; Shahab Sokhansanj; Christopher T. Wright; J. Richard Hess; Richard D. Boardman

2011-08-01

431

STABILIZATION\\/SOLIDIFICATION (S\\/S) OF Pb AND W CONTAMINATED SOILS USING TYPE I\\/II PORTLAND CEMENT, SILICA FUME CEMENT AND CEMENT KILN DUST  

Microsoft Academic Search

Stabilization\\/solidification (S\\/S) processes were utilized to immobilize lead (Pb) and tungsten (W) in contaminated soils, the inclusion of W motivated by the use of the new W-based ammunition. Artificially contaminated soils were prepared by mixing either kaolinite or montmorillonite with 10% Pb and 1% W (all percentages by dry weight). Type I\\/II Portland cement (PC), silica fume cement (SFC) and

D. G. GRUBB

432

Process Integration of Bioethanol from Sugar Cane and Hydrogen Production  

NASA Astrophysics Data System (ADS)

In this study several alternatives for process integration of bioethanol from sugar cane and hydrogen production were evaluated. Bioethanol was produced above all in the fermentation of sweetened juice from sugar cane, stillage was removed. Stillage and bagasse are the process byproducts. The bioethanol steam reforming is an endothermic catalytic process when vaporized ethanol and steam are fed using a 1:6 molar ratio to reformer with a Ni-catalyst at atmospheric pressure and 350xC. Taking into account the processes properties mentioned above, it is possible to integrate the bioethanol production from sugar cane and its reforming by using byproducts like bagasse and stillage and to produce energy for steam reforming and bioethanol solution concentration by direct firing (for bagasse) or anaerobic digestion to get methane (for stillage).

Hernandez, L.; Kafarov, V.

433

Process development of high performance CIGS modules for mass production  

Microsoft Academic Search

The technology of Cu(In,Ga)Se2 (CIGS)-based solar modules is close to commercialisation. However, the high cost-reduction potential can only be realised with mass production. ZSW has developed all process steps for a 30 cm×30 cm CIGS line. Very high performance CIGS modules with an efficiency close to 13% and smaller mini-modules close to 15% were prepared with this line. Critical process

M. Powalla; B Dimmler

2001-01-01

434

Optimal biorefinery product allocation by combining process and economic modeling  

Microsoft Academic Search

The integrated biorefinery has the opportunity to provide a strong, self-dependent, sustainable alternative for the production of bulk and fine chemicals, e.g. polymers, fiber composites and pharmaceuticals as well as energy, liquid fuels and hydrogen. Although most of the fundamental processing steps involved in biorefining are well-known, there is a need for a methodology capable of evaluating the integrated processes

N. E. Sammons Jr; W. Yuana; M. R. Eden; B. Aksoy; H. T. Cullinan

2008-01-01

435

Reactions and surface interactions of saccharides in cement slurries.  

PubMed

Glucose, maltodextrin, and sucrose exhibit significant differences in their alkaline reaction properties and interactions in aluminate/silicate cement slurries that result in diverse hydration behaviors of cements. Using 1D solution- and solid-state (13)C nuclear magnetic resonance (NMR), the structures of these closely related saccharides are identified in aqueous cement slurry solutions and as adsorbed on inorganic oxide cement surfaces during the early stages of hydration. Solid-state 1D (29)Si and 2D (27)Al{(1)H} and (13)C{(1)H} NMR techniques, including the use of very high magnetic fields (18.8 T), allow the characterization of the hydrating silicate and aluminate surfaces, where interactions with adsorbed organic species influence hydration. These measurements establish the molecular features of the different saccharides that account for their different adsorption behaviors in hydrating cements. Specifically, sucrose is stable in alkaline cement slurries and exhibits selective adsorption at hydrating silicate surfaces but not at aluminate surfaces in cements. In contrast, glucose degrades into linear saccharinic or other carboxylic acids that adsorb relatively weakly and nonselectively on nonhydrated and hydrated cement particle surfaces. Maltodextrin exhibits intermediate reaction and sorption properties because of its oligomeric glucosidic structure that yields linear carboxylic acids and stable ring-containing degradation products that are similar to those of the glucose degradation products and sucrose, respectively. Such different reaction and adsorption behaviors provide insight into the factors responsible for the large differences in the rates at which aluminate and silicate cement species hydrate in the presence of otherwise closely related saccharides. PMID:22834946

Smith, Benjamin J; Roberts, Lawrence R; Funkhouser, Gary P; Gupta, Vijay; Chmelka, Bradley F

2012-10-01

436

An extended model of design process of lean production systems by means of process variables  

Microsoft Academic Search

In this paper, we present an axiomatic modeling of lean production system design, using process variables (PVs). So far, we had developed a model for conceptual design of lean production systems by means of FR–DP relationships, the key characteristics of axiomatic design (AD) methodology, appeared in the proceedings of Second International Conference of Axiomatic Design. Albeit the model in question

Mahmoud Houshmand; Bizhan Jamshidnezhad

2006-01-01

437

LITERATURE SURVEY ON CEMENTS FOR REMEDIATION OF DEFORMED CASING IN GEOTHERMAL WELLS  

SciTech Connect

Brookhaven National Laboratory was requested to conduct a literature survey for the best available cement to use in the proposed casing patch as part of the Geothermal Drilling Organization (GDO) project on remediation of deformed casings. A total of 50 wells has been identified with deformed production casing in Unocal's portion of The Geysers geothermal field. Reduced internal diameter and casing doglegs result in lost production and the possible need for abandonment. The cause of the deformations is believed to be formation movement along fault planes and/or along weaker layers or interfaces between high impedance contrast media. Apparently, it is unclear whether shear or axial compression is the dominant failure mechanism. A procedure to address the casing deformation and avoid abandonment of these wells has been developed as described in the Geysers Deformed Casing Remediation Proposal. The proposed remediation procedure involves isolation of the zone of interest with an inflatable packer, milling the deformed casing and cementing a 7 inch diameter liner to extend approximately 100 ft above and 100 ft below the milled zone. During the milling operation it is possible that the original cement and surrounding formation may slough away. In order to specify a suitable cement formulation for the casing patch it is first necessary to identify and understand the deformation mechanism/s operating in The Geysers field. Subsequently, the required cement mechanical properties to withstand further deformation of the repaired system must be defined. From this information it can be determined whether available cement formulations meet these requirements. In addition to The Geysers, other geothermal fields are at possible risk of casing deformation due to subsidence, seismic activity, lateral and vertical formation movement or other processes. Therefore, the proposed remediation procedure may have applications in other fields. The literature survey focused on published properties for cements used in geothermal and oil well applications and the experiences of well casing deformation occurring in oil and gas fields. Dr. Mike Bruno of Terralog Technologies kindly supplied a reference list from the DEA (Drilling Engineering Association) 99 Project on Analysis of Well Casing Damage Induced by Reservoir Compaction and Overburden Shear.

ALLAN,M.L.; PHILIPPACOPOULOS,A.J.

1998-11-01

438

Barnacle cement: a polymerization model based on evolutionary concepts  

PubMed Central

Summary Enzymes and biochemical mechanisms essential to survival are under extreme selective pressure and are highly conserved through evolutionary time. We applied this evolutionary concept to barnacle cement polymerization, a process critical to barnacle fitness that involves aggregation and cross-linking of proteins. The biochemical mechanisms of cement polymerization remain largely unknown. We hypothesized that this process is biochemically similar to blood clotting, a critical physiological response that is also based on aggregation and cross-linking of proteins. Like key elements of vertebrate and invertebrate blood clotting, barnacle cement polymerization was shown to involve proteolytic activation of enzymes and structural precursors, transglutaminase cross-linking and assembly of fibrous proteins. Proteolytic activation of structural proteins maximizes the potential for bonding interactions with other proteins and with the surface. Transglutaminase cross-linking reinforces cement integrity. Remarkably, epitopes and sequences homologous to bovine trypsin and human transglutaminase were identified in barnacle cement with tandem mass spectrometry and/or western blotting. Akin to blood clotting, the peptides generated during proteolytic activation functioned as signal molecules, linking a molecular level event (protein aggregation) to a behavioral response (barnacle larval settlement). Our results draw attention to a highly conserved protein polymerization mechanism and shed light on a long-standing biochemical puzzle. We suggest that barnacle cement polymerization is a specialized form of wound healing. The polymerization mechanism common between barnacle cement and blood may be a theme for many marine animal glues.

Dickinson, Gary H.; Vega, Irving E.; Wahl, Kathryn J.; Orihuela, Beatriz; Beyley, Veronica; Rodriguez, Eva N.; Everett, Richard K.; Bonaventura, Joseph; Rittschof, Daniel

2009-01-01

439

Evaluation of mechanical properties of five cements for orthodontic band cementation.  

PubMed

The aim of this in vitro study was to compare the flexural, compressive and diametral tensile strengths of five cements used in orthodontics for band cementation. Twelve specimens of each cement were tested: 1 - GC Fuji Ortho Band (FJ), GC America Inc.; 2 - Meron (MR), Voco; 3 - Multi-Cure Glass Ionomer Band Cement (MC), 3M Unitek; 4 - Band-Lok (BL), Reliance Orthodontic Products; and 5 - Ketac Cem (KC), 3M ESPE. The results (mean) for diametral tensile strength were: 10.51 MPa (FJ), 9.60 MPa (MR), 20.04 MPa (MC), 42.80 MPa (BL), and 4.08 MPa (KC). The results for compressive strength were (in the same order): 64.50 MPa, 77.71 MPa, 94.21 MPa, 193.88 MPa, and 81.93 MPa. The results for flexural strength were (in the same order): 20.72 MPa, 25.84 MPa, 53.41 MPa, 137.41 MPa, and 20.50 MPa. The statistical analysis was performed by two-way ANOVA and Tukey tests with p-value £ 0.05. In terms of diametral tensile strength, BL showed the highest strength statistically, and MC, the second highest. In terms of compressive tensile strength, BL showed the highest strength statistically, and FJ did not attain the minimum recommended strength. In terms of flexural tensile strength, BL cement was superior to MC, and MR, FJ and KC were equivalent and inferior to BL and MC. PMID:23459769

Aguiar, Diego Andrei; Ritter, Daltro Enéas; Rocha, Roberto; Locks, Arno; Borgatto, Adriano Ferreti

2013-01-01

440

Mineral resource of the month: hydraulic cement  

USGS Publications Warehouse

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.

van Oss, Hendrik G.

2012-01-01

441

Global warming impact on the cement and aggregates industries  

Microsoft Academic Search

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

Davidovits

1994-01-01

442

Material, process, and product design of thermoplastic composite materials  

Microsoft Academic Search

Thermoplastic composites made of polypropylene (PP) and E-glass fibers were investigated experimentally as well as theoretically for two new classes of product designs. The first application was for reinforcement of wood. Commingled PP\\/glass yarn was consolidated and bonded on wood panel using a tie layer. The processing parameters, including temperature, pressure, heating time, cooling time, bonding strength, and bending strength

Heming Dai

2001-01-01

443

NATO/CCMS PILOT STUDY ON CLEAN PRODUCTS & PROCESSES  

EPA Science Inventory

Led by the United States, represented by the U.S. Environmental Protection Agency's (EPA's) National Risk Management Research Laboratory, the Pilot Study on Clean Products and Processes was instituted to create an international forum where current trends, developments, and expert...