These are representative sample records from Science.gov related to your search topic.
For comprehensive and current results, perform a real-time search at Science.gov.
1

Alternative Fuel for Portland Cement Processing  

SciTech Connect

The production of cement involves a combination of numerous raw materials, strictly monitored system processes, and temperatures on the order of 1500 °C. Immense quantities of fuel are required for the production of cement. Traditionally, energy from fossil fuels was solely relied upon for the production of cement. The overarching project objective is to evaluate the use of alternative fuels to lessen the dependence on non-renewable resources to produce portland cement. The key objective of using alternative fuels is to continue to produce high-quality cement while decreasing the use of non-renewable fuels and minimizing the impact on the environment. Burn characteristics and thermodynamic parameters were evaluated with a laboratory burn simulator under conditions that mimic those in the preheater where the fuels are brought into a cement plant. A drop-tube furnace and visualization method were developed that show potential for evaluating time- and space-resolved temperature distributions for fuel solid particles and liquid droplets undergoing combustion in various combustion atmospheres. Downdraft gasification has been explored as a means to extract chemical energy from poultry litter while limiting the throughput of potentially deleterious components with regards to use in firing a cement kiln. Results have shown that the clinkering is temperature independent, at least within the controllable temperature range. Limestone also had only a slight effect on the fusion when used to coat the pellets. However, limestone addition did display some promise in regards to chlorine capture, as ash analyses showed chlorine concentrations of more than four times greater in the limestone infused ash as compared to raw poultry litter. A reliable and convenient sampling procedure was developed to estimate the combustion quality of broiler litter that is the best compromise between convenience and reliability by means of statistical analysis. Multi-day trial burns were conducted at a full-scale cement plant with alternative fuels to examine their compatibility with the cement production process. Construction and demolition waste, woodchips, and soybean seeds were used as alternative fuels at a full-scale cement production facility. These fuels were co-fired with coal and waste plastics. The alternative fuels used in this trial accounted for 5 to 16 % of the total energy consumed during these burns. The overall performance of the portland cement produced during the various trial burns performed for practical purposes very similar to the cement produced during the control burn. The cement plant was successful in implementing alternative fuels to produce a consistent, high-quality product that increased cement performance while reducing the environmental footprint of the plant. The utilization of construction and demolition waste, woodchips and soybean seeds proved to be viable replacements for traditional fuels. The future use of these fuels depends on local availability, associated costs, and compatibility with a facilityâ??s production process.

Anton K. Schindler; Steve R. Duke; Thomas E. Burch; Edward W. Davis; Ralph H. Zee; David I. Bransby; Carla Hopkins; Rutherford L. Thompson; Jingran Duan; Vignesh Venkatasubramanian; Stephen Giles.

2012-06-30

2

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

3

Process for cementing geothermal wells  

DOEpatents

A pumpable slurry of coal-filled furfuryl alcohol, furfural, and/or a low molecular weight mono- or copolymer thereof containing, preferably, a catalytic amount of a soluble acid catalyst is used to cement a casing in a geothermal well.

Eilers, Louis H. (Inola, OK)

1985-01-01

4

Energy audit and conservation opportunities for pyroprocessing unit of a typical dry process cement plant  

Microsoft Academic Search

Cement production process has been highly energy and cost intensive. The cement plant requires 8784 h per year of the total operating hours to produce 640,809 tonnes of clinker. To achieve effective and efficient energy management scheme, thermal energy audit analysis was employed on the pyroprocessing unit of the cement plant. Fuel combustion generates the bulk of the thermal energy for the

G. Kabir; A. I. Abubakar; U. A. El-Nafaty

2010-01-01

5

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

PubMed

This paper describes an industrial process for stabilising sewage sludge (SS) with lime and evaluates the viability of the stabilised product, denominated Neutral, as a raw material for the cement industry. Lime not only stabilised the sludge, raised the temperature of the mix to 80-100°C, furthering water evaporation, portlandite formation and the partial oxidation of the organic matter present in the sludge. Process mass and energy balances were determined. Neutral, a white powder consisting of portlandite (49.8%), calcite (16.6%), inorganic oxides (13.4%) and organic matter and moisture (20.2%), proved to be technologically apt for inclusion as a component in cement raw mixes. In this study, it was used instead of limestone in raw mixes clinkerised at 1400, 1450 and 1500°C. These raw meals exhibited greater reactivity at high temperatures than the limestone product and their calcination at 1500°C yielded clinker containing over 75% calcium silicates, the key phases in Portland clinker. Finally, the two types of raw meal (Neutral and limestone) were observed to exhibit similar mineralogy and crystal size and distribution. PMID:22119052

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

2012-03-01

6

CONSTRUCTION-GRADE CEMENT PRODUCTION FROM CONTAMINATED SEDIMENTS USING  

E-print Network

1 CONSTRUCTION-GRADE CEMENT PRODUCTION FROM CONTAMINATED SEDIMENTS USING CEMENT-LOCKTM TECHNOLOGY A developed the Cement-LockTM Technology a versatile, cost-effective, and environmentally friendly manufacturing technology for producing construction-grade cements from a wide variety of contaminated waste

Brookhaven National Laboratory

7

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

8

Uncertainty Analysis of CO2 Emissions from Cement Production  

Microsoft Academic Search

This study is focused to the uncertainty analysis of the CO2 emitted from the cement clinker production. The algorithms developed utilize the mass and energy balances describing the combustion and process emissions and apply the error propagation technique to evaluate the uncertainty estimate of each dependent variable. An example of application of the proposed model is demonstrated and a parametric

TSAMATSOULIS DIMITRIS

9

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

10

Waste with chrome in the Portland cement clinker production.  

PubMed

Hazardous wastes, coming from industries are usually used in the Portland cement production in order to save energy, costs and/or stabilize toxic substances and heavy metals inside the clinker. This work focuses on the effect produced on the Portland cement clinker when it is obtained using tanned leather shavings whit chrome salts as part of the process. The raw materials were clinkered in laboratory with different percentages of shavings, which contained 2% of Cr(2)O(3). DTA-TG of the raw mixtures was performed to evaluate the thermal behavior changes that can take place during the clinkering process, analyzing the crystalline phases obtained by XRD. The milling behavior of clinkers was studied, analyzing also the refractoriness variation on those clinkers. The chrome retention was evaluated by leaching tests. The structural modification determined by the chrome presence in the silicate structure brought consequences in the hydration speed, mechanical resistance and pore distribution. PMID:17292542

Trezza, M A; Scian, A N

2007-08-17

11

The use of waste ceramic tile in cement production  

SciTech Connect

In ceramic tile production, because of various reasons, unsold fired products come out. These are waste tiles and only a little part of them are used. Remainings create environmental problems. If these waste tiles are used in cement production, this pollution decreases. In this study, usage of waste tile as pozzolan was studied. Waste tile was added into Portland cement in 25%, 30%, 35%, and 40% weight ratios. Pozzolanic properties of waste tile and setting time, volume stability, particle size, density, specific surface area, and strength of cement including waste tile were investigated. The test results indicated that the waste tiles show pozzolanic properties, and chemical and physical properties of the cement including tile conforms to cement standard up to the addition of 35% waste tile.

Ay, N.; Uenal, M.

2000-03-01

12

Environmental assessment of cement/foundry sludge products.  

PubMed

This work deals with the environmental assessment of products based on cement and a waste from a cast iron activity. The waste is a foundry sludge from wastewater treatment previously characterized. This industrial waste shows a high water content (62.4%) and a hazardous behavior due to its metallic content mainly Zn (16.5%), together with a low fraction of organic pollutants, mainly phenolic compounds. The feasibility of immobilizing both typs of contaminants was studied using Portland cement as binder at different cement/waste ratios. The parameters of environmental control were the ecotoxicity and mobilization of zinc and phenolic compounds, all determined on the basis of compliance leaching tests. The acid neutralization capacity of the cement/waste products was measured in order to obtain information on their buffering capacity. Experimental results from chemical analysis of leachates led to a non ecotoxic character of cement/waste products Although the metallic ions were mobilized within the cement mattices, the organic matter did not allow the formation of monolithic forms and an efficient immobilization of phenolic compounds. Concerning the acid neutralization capacity, this parameter was shown to depend mainly on the quantity of cement, although a decrease in alkalinity was observed when the amount of water in the cement/waste products increased. PMID:12803251

Ruiz, M C; Andrés, A; Irabien, A

2003-05-01

13

Study of ammonia source at a Portland Cement production plant (journal version)  

SciTech Connect

A source and process-sampling study was conducted at a dry process Portland Cement production plant. One aspect of the study focused on the source or point of NH3 within the production process. An extensive number of process solids from raw feeds to baghouse solids were collected and analyzed for NH4(1+). The results show the presence of NH4(1+) in many process samples, and that its collection efficiency in the baghouse is related to baghouse temperature. The data also show that NH/sub 3/ is derived from the shale used in the raw feed at this cement production plant.

Cheney, J.L.; Knapp, K.T.

1987-01-01

14

A Review of Emerging Energy-efficiency and CO2 Emission-reduction Technologies for Cement and Concrete Production  

E-print Network

facing bricks and durable pavers (CalStar Products 2012). 2.4.3. Geopolymer Cement Geopolymer materials fit in the category of current innovative technology for the construction industry. In contrast to Portland cement, geopolymers rely... on minimally processed natural materials or industrial byproducts as binding agents. Potential energy and CO2 savings from the use of geopolymers are significant. Geopolymer cements that are used as binders are composed of a reactive solid component...

Hasanbeigi, A.; Price, L.; Lin, E.

2012-01-01

15

Structurization Processes in the System Cement-Water with Chemical Addition of Glyoxal  

NASA Astrophysics Data System (ADS)

Influence of the aqueous glyoxal solution as a chemical additive on the processes of hydration and structurization of cement stone is considered. Physical patterns of diffusion and particle mass transfer deep into cement grains are studied. It is demonstrated that the mechanism of increasing strength and change of the setting time for samples based on cement binders consists of the following processes: intensification of diffusion interaction of binder grains with water molecules; more ordered structural formations with closer sizes formed in a solidifying system; glyoxal and products of its interaction retaining water and gradually transmitting it to the system of new structural formations in later solidification stages thereby increasing the degree of hydration of cement particles.

Gorlenko, N. P.; Sarkisov, Yu. S.; Volkov, V. A.; Kul'chenko, A. K.

2014-06-01

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

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

18

Recycling of municipal solid waste incineration fly ash for ordinary Portland cement production: A real-scale test  

Microsoft Academic Search

The study present in this paper investigates the feasibility of clinker production using water washed MSWI (municipal solid waste incineration) fly ash in addition to cement raw materials. The tested fly ashes were washed and reused as raw material (with dosage of 1% of cement raw material (w\\/w)). The optimization of the MSWI fly ash washing process was carried out

Lei Wang; Yiying Jin; Yongfeng Nie; Rundong Li

2010-01-01

19

Aluminum dross oxide products for the portland cement industry  

SciTech Connect

Recovery of aluminum metal from drosses is a major factor in the recyclability success story enjoyed by the United States aluminum industry. Today`s modern dross processor uses the latest technology to maximize metal recovery at the lowest cost while complying with all environmental laws and regulations. Most dross processors, however, pay little attention to the resulting saltcake, the end residual of dross recycling, and rely on landfills for disposition of this material. The alternative is to recycle the saltcake, but the success of this technology is dependent on the development of reliable outlets for each of the saltcake constituents. This paper discusses the evolution of an aluminum dross oxide processing technology that produces an economically attractive source of alumina for the production of portland cement.

Zuck, D.A. [IMSAMET, Inc., Litchfield Park, AZ (United States)

1995-12-31

20

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

21

Cancer mortality study among French cement production workers  

Microsoft Academic Search

Purpose  To analyse the mortality and its causes, especially cancer, among French cement production workers.\\u000a \\u000a \\u000a \\u000a Methods  A cohort of all workers employed at least 1 year in one of the main four cement companies in France was assembled (9,118 workers,\\u000a 122,124 person-years of follow-up between 1990 and 2005). A common job titles classification was used to analyse occupational\\u000a risk factors. We conducted a

William DabMichel; Michel Rossignol; Danièle Luce; Jacques Bénichou; Alain Marconi; Philippe Clément; Michel Aubier; Denis Zmirou-Navier; Lucien Abenhaim

2011-01-01

22

Experiences with the design of large size cement plants - Process and layout considerations in pyroprocess systems  

Microsoft Academic Search

The important task to update production process by means of latest technological developments must be accomplished by both the equipment supplier and the cement producer. The equipment supplier, being the technological partner to the industry can thus help greatly to stay competitive in the changing face of the industry. Off late due to the rapid growth rate of Indian economy

A. K. Dembla; M. Mersmann

2007-01-01

23

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

24

Optimization Research for Cement Materials Mine Production Scheduling System Based on Multi-Agent Technology  

Microsoft Academic Search

According to the Multi-Agent technology modeling theory, combined with the actual situation of the cement materials open-pit mine, using adaptive neural-fuzzy inference system (Anfis) and classic modeling method respectively establishes the blasting system agent model, the transportation production system and the broken system agent model. Through the production task distribution coordinate the operation process of different Agents, Blasting system agent

Yang Shi-jiao; Dai Jian-yong; Wu Chang-zhen; Li Bing; Huo Xiao-yu

2012-01-01

25

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

PubMed

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 obtained from optimum compositions, were also evaluated. From the results it is observed that all of the major components of ordinary Portland cement (OPC) clinkers are present in the produced clinkers. Results also show the volatilization of considerable amounts of Na, K, Pb, Zn and Cd during the production of clinkers. However, major parts of the toxic elements remaining in the clinkers appear to be immobilized in the clinkers phases. Hydration studies of the clinkers obtained from optimum compositions show that the clinkers prepared from raw MSW ash are more reactive than the washed MSW ash based clinkers. TG/DTA analyses of the hydrated pastes show the formation of hydration products, which are generally found in OPC and OPC derived cements. The initial study, therefore, shows that more than 44% of MSW ash with the addition of very small amounts of silica and iron oxide can be used to produce cement clinkers. The amount of CaCO3 necessary to produce clinkers (approximately 50%) is also smaller than the same required for the conventional process (more than 70%). PMID:16920348

Saikia, Nabajyoti; Kato, Shigeru; Kojima, Toshinori

2007-01-01

26

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

27

Thermokineticanalysis of the hydration process of calcium phosphate cement  

Microsoft Academic Search

A microcalorimeter (Setaram c-80) was used\\u000a to study the thermokinetics of the hydration process of calcium phosphate\\u000a cement (CPC), a biocompatible biomaterial used in bone repair. The hydration\\u000a enthalpy was determined to be 35.8 J g–1\\u000a at 37.0°C when up to 80 mg CPC was dissolved in 2 mL of citric buffer.\\u000a In the present study, parameters related to time

W. Y. Gao; Y. W. Wang; L. M. Dong

2006-01-01

28

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...

29

Reaction processes and permeability changes during CO2-rich brine flow through fractured Portland cement  

NASA Astrophysics Data System (ADS)

So far, cement alteration was principally studied experimentally using batch reactor (with static or renewed fluid). All exhibit similar carbonation mechanisms. The acidic solution, formed by the dissolution of the CO2 into the pore water or directly surrounding the cement sample, diffuses into the cement and induces dissolution reactions of the cement hydrates in particular portlandite and CSH. The calcium released by the dissolution of these calcium bearing phases combining with carbonate ions of the fluid forms calcium carbonates. The cement pH, initially around 13, falls to values where carbonate ion is the most dominant element (pH ~ 9), then CaCO3 phases can precipitate. These studies mainly associate carbonation process with a reduction of porosity and permeability. Indeed an increase of volume (about 10%) is expected during the formation of calcite from portlandite (equation 2) assuming a stoichiometric reaction. Here we investigated the cement alteration mechanisms in the frame of a controlled continuous renewal of CO2-rich fluid in a fracture. This situation is that expected when seepage is activated by the mechanical failure of the cement material that initially seals two layers of distinctly different pressure: the storage reservoir and the aquifer above the caprock, for instance. We study the effect of flow rates from quasi-static flow to higher flow rates for well-connected fractures. In the quasi-static case we observed an extensive conversion of portlandite (Ca(OH)2) to calcite in the vicinity of the fracture similar to that observed in the published batch experiments. Eventually, the fracture was almost totally healed. The experiments with constant flow revealed a different behaviour triggered by the continuous renewing of the reactants and withdrawal of reaction products. We showed that calcite precipitation is more efficient for low flow rate. With intermediate flow rate, we measured that permeability increases slowly at the beginning of the experiment and then remains constant due to calcite precipitation in replacement of CSH and CH into fracture border. With higher flow rate, we measured a constant permeability which can be explained by the development of a highly hydrated Si-rich zone which maintains the initial fracture aperture during all over the experiment while noticeable mass is released from the sample. These preliminary results emphasize that more complex behaviours than that envisaged from batch experiments may take place in the vicinity of flowing fractures. We demonstrated that if only micro-cracks appear in the cement well, carbonation reaction may heal these micro-cracks and mitigate leakage whereas conductive fractures allowing high flow may represent a risk of perennial leakage because the net carbonation process, including the calcite precipitation and its subsequent re-dissolution, is sufficiently to heal the fracture. However, the precipitation of Si-rich amorphous phases may maintain the initial fracture aperture and limit the leakage rate. Keywords: leakage, cement alteration, flow rate, fracture, permeability changes, reaction processes.

Abdoulghafour, H.; Luquot, L.; Gouze, P.

2012-12-01

30

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

SciTech Connect

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 and fall in counterflow with the combustion gases. During this time, which is of order a few seconds and an order of magnitude less than the state-of-the-art kiln process, the pellets heat-up, dry, calcine and are partially clinkered. They land on a fixed bed where clinkering is completed and heat is recovered from the pellets to the counter-flowing combustion air. Energy input to the process is through the direct combustion of natural gas in the clinkering and calcining zones of the shaft. This report describes the work performed in the first phase of the development program. Flow stability, batch agglomeration, and clinkering tests were performed to validate the process concept. An interim economic analysis comparing likely commercial installation options to the state-of-the-art process was made.

Zappa, O.L.

1989-04-01

31

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

32

Heuristic economic assessment of the Afghanistan construction materials sector: cement and dimension stone production  

USGS Publications Warehouse

Over the past decade, the U.S. Government has invested more than $106 billion for physical, societal, and governmental reconstruction assistance to Afghanistan (Special Inspector General for Afghanistan Reconstruction, 2012a). This funding, along with private investment, has stimulated a growing demand for particular industrial minerals and construction materials. In support of this effort, the U.S. Geological Survey released a preliminary mineral assessment in 2007 on selected Afghan nonfuel minerals (Peters and others, 2007). More recently, the 2007 mineral assessment was updated with the inclusion of a more extensive array of Afghan nonfuel minerals (Peters and others, 2011). As a follow-up on the 2011 assessment, this report provides an analysis of the current use and prospects of the following Afghan industrial minerals required to manufacture construction materials: clays of various types, bauxite, gypsum, cement-grade limestone, aggregate (sand and gravel), and dimension stone (sandstone, quartzite, granite, slate, limestone, travertine, marble). The intention of this paper is to assess the: Use of Afghan industrial minerals to manufacture construction materials, Prospects for growth in domestic construction materials production sectors, Factors controlling the competitiveness of domestic production relative to foreign imports of construction materials, and Feasibility of using natural gas as the prime source of thermal energy and for generating electrical energy for cement production. The discussion here is based on classical principles of supply and demand. Imbedded in these principles is an understanding that the attributes of supply and demand are highly variable. For construction materials, demand for a given product may depend on seasons of the year, location of construction sites, product delivery time, political factors, governmental regulations, cultural issues, price, and how essential a given product might be to the buyer. Moreover, failure on the supply side to mirror such attributes can be deal-breakers in a transaction. For qualitative interpretation of the findings in this report, the value chain was used to conceptualize the relation between supply and demand. Although quantitative data on the Afghan construction materials sector have been hard to come by, the premise herein was that qualitative aspects of supply and demand are revealed by following the flow of funding through projects of varying sizes. It was found that the spectrum of attributes on the demand side of large multimillion dollar reconstruction projects is generally high dimensional, distributed over a broad line of construction materials at diverse locations, and in varying quantities. As interpreted herein, project funds dispensed at the higher hierarchical levels of a project are often concentrated on procurement of construction materials and services at the upper end of the value chain. In contrast, project funds dispensed at the lower hierarchical levels are disseminated across a multiplicity of subprojects, thus restricting project acquisitions to the lower end of the value chain. Evidence suggests that under the current conditions in Afghanistan producers of construction materials at the lower end of the value chain (adobe brick, aggregate, low-end marble products) can successfully compete in local markets and turn a profit. In contrast, producers of energy-intensive products such as cement will continue to face intense competition from imports, at least in the near-term. In the long-term, as infrastructure issues are resolved, and as business conditions in Afghanistan improve, domestic producers will have a locational advantage in establishing a solid niche in their respective home markets. In the process of tendering properties for cement production, the pivotal issues of abundant, reliable, and cost-effective thermal and electrical energy sources for cement production have become prominent. Over the past 50 years, powdered coal and natural gas have been proven to be excellent fuels for firing kilns at cement plants, and bot

Mossotti, Victor G.

2014-01-01

33

Effect of fine steel slag powder on the early hydration process of portland cement  

Microsoft Academic Search

Hydration heat evolution, non-evaporative water, setting time and SEM tests were performed to investigate the effect of fine\\u000a steel slag powder on the hydration process of Portland cement and its mechanism. The results show that the effect of fine\\u000a steel slag powder on the hydration process of Portland cement is closely related to its chemical composition, mineral phases,\\u000a fineness, etc.

Hu Shuguang; He Yongjia; Lu Linnu; Ding Qingjun

2006-01-01

34

Anode-support system for the direct electrorefining of cement copper Part I: Process conditions using horizontal rotary cathodes  

Microsoft Academic Search

This paper describes a preliminary study towards a modified anode-support system for the direct electrorefining of cement copper. The proposed system is an alternative process for small mines that produce cement after leaching of copper oxide minerals. It is feasible to utilize a cell provided with a horizontal AISI-316 stainless steel mesh covered with a layer of cement copper as

R. Gana; M. Figueroa; L. Kattan; J. M. Sánchez; M. A. Esteso

1995-01-01

35

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

36

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))

1991-01-01

37

Minerals recovery from Salton Sea geothermal brines: a literature review and proposed cementation process  

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 metal 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 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.

1982-01-01

38

Processing of Sugarcane Bagasse ash and Reactivity of Ash-blended Cement Mortar  

NASA Astrophysics Data System (ADS)

Sugarcane bagasse ash (SCBA), a sugar-mill waste, has the potential of a partial cement replacement material if processed and obtained under controlled conditions. This paper discusses the reactivity of SCBA obtained by control burning of sugarcane bagasse procured from Punjab province of India. X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques were employed to ascertain the amorphousness and morphology of the minerals ash particles. Destructive and non-destructive tests were conducted on SCBA-blended mortar specimens. Ash-blended cement paste specimens were analyzed by XRD, thermal analysis, and SEM methods to evaluate the hydration reaction of SCBA with cement. Results showed that the SCBA processed at 600°C for 5 hours was reactive as ash-blended mortar specimens with up to 15% substitution of cement gave better strength than control specimens.

Ajay, Goyal; Hattori, Kunio; Ogata, Hidehiko; Ashraf, Muhammad

39

Impact of hardening conditions on to stabilized\\/solidified products of cement–sewage sludge–jarosite\\/alunite  

Microsoft Academic Search

The main objective of this work is to investigate a viable alternative for the final disposal of sewage sludge from urban wastewater treatment plants using a mixture with cement and jarosite\\/alunite (J\\/A) precipitate to develop new construction materials. J\\/A precipitate is a waste product of a new hydrometallurgical process, which was developed in order to treat economically low-grade nickel oxide

A. Cheilas; M. Katsioti; A. Georgiades; O. Malliou; C. Teas; E. Haniotakis

2007-01-01

40

Cementation of Colloidal Particles on Electrodes in a Galvanic Microreactor  

E-print Network

processing, galvanic corrosion, cementation, reaction products INTRODUCTION Colloidal crystals have the galvanic corrosion of copper microelectrodes embedded in a gold substrate and immersed in an acidicCementation of Colloidal Particles on Electrodes in a Galvanic Microreactor Linda Jan, Christian

Aksay, Ilhan A.

41

Utilization of the waste phosphogypsum for the Portland cement clinker production  

Microsoft Academic Search

This paper presents the results of investigation on the utilization of the phosphogypsum for the Portland cement clinker production. Characterization of the phosphogypsum and raw materials for rotary kilns was performed. Phosphogypsum, in quantities of 1%, 2%, 3% and 5%, was added to raw meal from regular production of rotary kiln and then the homogenization of raw meals and their

M. Ili?; S. Mileti?; R. Munitlak

1999-01-01

42

Characterization of Cement Alteration Process by Transmission Electron Microscopy with High Spatial Resolution  

Microsoft Academic Search

Application tests for advanced TEM analysis techniques were carried out to study the cement alteration processes associated with water penetration at high spatial resolution. Prior to TEM analysis, we measured the changes in the penetration coefficient and determined the characteristics of the penetrating water in order to gain a fuller understanding of the overall process. These experiments revealed that the

Shinya MIYAMOTO; Seiichiro UEHARA; Michitaka SASOH; Mitsuyoshi SATO; Masumitsu TOYOHARA; Kazuya IDEMITSU; Syo MATSUMURA

2006-01-01

43

Investigation of the energy-saving process of cement dispersion in a helium atmosphere  

NASA Astrophysics Data System (ADS)

The process of commercial cement grinding in a helium atmosphere has been investigated in comparison with the process in an air atmosphere. Raw material particles have been sorted by sizes. Curves of helium release from the raw material after its grinding in air and in helium in the temperature range T = 20-1200°C have been constructed and analyzed. The influence of the character of water molecule adsorption on raw material cement particles before and after grinding in air and in helium and on the shape of helium release curves has been revealed.

Klyavin, O. V.; Aruev, N. N.; Chernov, Yu. M.; Drinberg, A. S.; Fedorov, V. Yu.; Shpeizman, V. V.

2014-06-01

44

Hydration process of cement containing fly ash and silica fume: The first 24 hours  

SciTech Connect

Results from studies on the early hydration (till the 24th hour) of cements mixed with fly ash, silica fume or a combination of both, called Pozzolit, are presented. The active role of the Pozzolit mineral additive was revealed by DTA, XRD and IRS analyses. The effect of the additive is expressed in increased total amount of hydration products and decreased portlandite content.

Lilkov, V. [Univ. of Mining and Geology, Sofia (Bulgaria)] [Univ. of Mining and Geology, Sofia (Bulgaria); Dimitrova, E.; Petrov, O.E. [Bulgarian Academy of Sciences, Sofia (Bulgaria)] [Bulgarian Academy of Sciences, Sofia (Bulgaria)

1997-04-01

45

[Cancer morbidity risks among workers of asbestos-cement productions].  

PubMed

The retrospective assessment of morbidity rates and cancer pathology risks in workers of asbestosis-cement enterprises of Ukraine has been made. It was established that annual cancer morbidity among workers makes 88,1 per 100 000 of workers (RR = 0.26, CI 95 % 0.06-1.01). The most often cancer pathology was located in digestive organs (48.1%), respiratory organs (18.5%) (lung cancer--11.1%). The mesothelioma of pleura, peritoneum and pericardium were not found. The risks (odds ratio--OR) of cancer morbidity were increased for such organs as: respiratory organs (OR = 2.37), skin (OR = 1.78), digestive organs (OR = 1.34). PMID:18467971

Nagornaia, A M; Varivonchik, D V; Kundiev, Iu I; Fedorenko, Z P; Gorokh, E L; Gulak, L O; Vitte, P N; Karakashian, A N; Lepeshkina, T R; Martynovskaia, T Iu

2008-01-01

46

Technological features of cementation of liquid organic wastes from radiochemical production and NPP  

SciTech Connect

One method to manage liquid radioactive wastes is to incorporate them into inorganic materials. At VNINM, work was performed to cement spent oils and extractants and to determine final product properties. Attention was paid to a choice of emulsifiers. Parameters investigated included emulsifier availability, stability, and incorporability into a matrix material.

Belyaeva, T.B.; Kiselev-Dmitriev, A.L.; Masanov, O.L. [A.A. Bochvar Scientific Research Institute of Inorganic Materials (Russian Federation)

1993-12-31

47

Effects of processing and materials variations on mechanical properties of lightweight cement composites  

SciTech Connect

Low-density/low-cost cement composites were fabricated. Carbon and alkali-resistant glass fibers were used to reinforce the matrix of industrial by-products; fly ash with silica fume, Portland cement, and calcium silicates were mixed in different proportions. The additional low density was obtained by adding perlite and foaming agents followed by hot water curing. The composites also were prepared by autoclave curing for comparison. The mechanical properties were improved by increasing the amount of silica fume, fly ash, and fibers.Both carbon fibers and alkali-resistant glass fibers were effective in reinforcing the matrices, but carbon fibers were superior to glass fibers. Fabrication techniques for producing lightweight cement composites that can substitute for autoclaved lightweight concrete was developed.

Park, S.B. [Chungnam National Univ., Taejon (Korea, Republic of). Dept. of Civil Engineering] [Chungnam National Univ., Taejon (Korea, Republic of). Dept. of Civil Engineering; Yoon, E.S. [Korea Inst. of Nuclear Safety, Taejon (Korea, Republic of). Dept. of Structural Systems and Site Evaluation] [Korea Inst. of Nuclear Safety, Taejon (Korea, Republic of). Dept. of Structural Systems and Site Evaluation; Lee, B.I. [Clemson Univ., SC (United States). Dept. of Ceramic and Materials Engineering] [Clemson Univ., SC (United States). Dept. of Ceramic and Materials Engineering

1999-02-01

48

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

49

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)...

50

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...

51

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

52

Formation of the Thermoelectric Candidate Chromium Silicide by Use of a Pack-Cementation Process  

NASA Astrophysics Data System (ADS)

Transition-metal silicides are reported to be good candidates for thermoelectric applications because of their thermal and structural stability, high electrical conductivity, and generation of thermoelectric power at elevated temperatures. Chromium disilicide (CrSi2) is a narrow-gap semiconductor and a potential p-type thermoelectric material up to 973 K with a band gap of 0.30 eV. In this work, CrSi2 was formed from Si wafers by use of a two-step, pack-cementation, chemical diffusion method. Several deposition conditions were used to investigate the effect of temperature and donor concentration on the structure of the final products. Scanning electron microscopy and x-ray diffraction analysis were performed for phase identification, and thermal stability was evaluated by means of thermogravimetric measurements. The results showed that after the first step, chromizing, the structure of the products was a mixture of several Cr-Si phases, depending on the donor (Cr) concentration during the deposition process. After the second step, siliconizing, the pure CrSi2 phase was formed as a result of Si enrichment of the initial Cr-Si phases. It was also revealed that this compound has thermoelectric properties similar to those reported elsewhere. Moreover, it was found to have exceptional chemical stability even at temperatures up to 1273 K.

Stathokostopoulos, D.; Chaliampalias, D.; Tarani, E.; Theodorakakos, A.; Giannoulatou, V.; Polymeris, G. S.; Pavlidou, E.; Chrissafis, K.; Hatzikraniotis, E.; Paraskevopoulos, K. M.; Vourlias, G.

2014-10-01

53

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

54

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

55

Process, Product, and Playmaking  

ERIC Educational Resources Information Center

This article examines relationships among process, product, and playmaking in a southeastern playwriting and performance program for teen girls, Playmaking for Girls (PFG). The authors have chosen to focus on tensions between process and product. Such tensions are present in the challenges teachers experience when privileging student-centered…

Fisher, Maisha T.; Purcell, Susie Spear; May, Rachel

2009-01-01

56

CO 2 emissions from Polish cement industry  

Microsoft Academic Search

The cement industry is one of the most significant sources of anthropogenic emissions of CO2. It is connected with the specific character of the production processes, during which great quantities of CO2 are produced. Basic actions to reduce CO2 emissions recommended by the European Union's, Reference Document on Best Available Techniques in the Cement and Lime Manufacturing Industries, include: reduction

Jan Deja; Alicja Uliasz-Bochenczyk; Eugeniusz Mokrzycki

2010-01-01

57

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

58

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

59

Butadiene production process overview  

Microsoft Academic Search

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

Wm. Claude White

2007-01-01

60

Modeling of a self-healing process in blast furnace slag cement exposed to accelerated carbonation  

NASA Astrophysics Data System (ADS)

In the current research, a mathematical model for the post-damage improvement of the carbonated blast furnace slag cement (BFSC) exposed to accelerated carbonation is constructed. The study is embedded within the framework of investigating the effect of using lightweight expanded clay aggregate, which is incorporated into the impregnation of the sodium mono-fluorophosphate (Na-MFP) solution. The model of the self-healing process is built under the assumption that the position of the carbonation front changes in time where the rate of diffusion of Na-MFP into the carbonated cement matrix and the reaction rates of the free phosphate and fluorophosphate with the components of the cement are comparable to the speed of the carbonation front under accelerated carbonation conditions. The model is based on an initial-boundary value problem for a system of partial differential equations which is solved using a Galerkin finite element method. The results obtained are discussed and generalized to a three-dimensional case.

Zemskov, Serguey V.; Ahmad, Bilal; Copuroglu, Oguzhan; Vermolen, Fred J.

2013-02-01

61

Alex Benson Cement Plants  

E-print Network

Alex Benson ATOC 3500 Cement Plants 4 Step Production Line: o Mine the Limestone: Cement plants of generating electricity by coal. o From Kiln Combustion CO2 ­ 2nd largest CO2 emitter behind electricity health effects Relative News; o "EPA Clamps down on Cement Plant Pollution" http

Toohey, Darin W.

62

Sets of Reports and Articles Regarding Cement Wastes Forms Containing Alpha Emitters that are Potentially Useful for Development of Russian Federation Waste Treatment Processes for Solidification of Weapons Plutonium MOX Fuel Fabrication Wastes for  

SciTech Connect

This is a set of nine reports and articles that were kindly provided by Dr. Christine A. Langton from the Savannah River Site (SRS) to L. J. Jardine LLNL in June 2003. The reports discuss cement waste forms and primarily focus on gas generation in cement waste forms from alpha particle decays. However other items such as various cement compositions, cement product performance test results and some cement process parameters are also included. This set of documents was put into this Lawrence Livermore National Laboratory (LLNL) releasable report for the sole purpose to provide a set of documents to Russian technical experts now beginning to study cement waste treatment processes for wastes from an excess weapons plutonium MOX fuel fabrication facility. The intent is to provide these reports for use at a US RF Experts Technical Meeting on: the Management of Wastes from MOX Fuel Fabrication Facilities, in Moscow July 9-11, 2003. The Russian experts should find these reports to be very useful for their technical and economic feasibility studies and the supporting R&D activities required to develop acceptable waste treatment processes for use in Russia as part of the ongoing Joint US RF Plutonium Disposition Activities.

Jardine, L J

2003-06-12

63

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

64

Fundamental considerations on the mechanisms of silver cementation onto zinc particles in the Merril–Crowe process  

Microsoft Academic Search

Studies on the Merrill–Crowe process as applied to silver recovery have shown that one half of the used zinc powder is wasted in water reduction at high cyanide concentrations, while the other half reduces silver ions from the cyanide solution. However, the cementation mechanisms as an electrochemical process taking place on the zinc surface do not explain the split of

G. Viramontes Gamboa; M. Medina Noyola; A. López Valdivieso

2005-01-01

65

Effects of test sample shape and surface production method on the fatigue behaviour of PMMA bone cement.  

PubMed

There is no consensus over the optimal criterion to define the fatigue life of bone cement in vitro. Fatigue testing samples have been made into various shapes using different surface preparation techniques with little attention being paid to the importance of these variations on the fatigue results. The present study focuses on the effect of test sample shape and surface production method on the fatigue results. The samples were manufactured with two cross sectional shapes: rectangular according to ISO 527 and circular according to ASTM F2118. Each shape was produced using two methods: direct moulding of the cement dough and machining from oversized rods. Testing was performed using two different bone cements: SmartSet GHV and DePuy CMW1. At least 10 samples of each category were tested, under fully reversed tension-compression fatigue stress at ±20MPa, to allow for Weibull analysis to compare results. The growth of fatigue cracks was observed by means of the changes in the absorbed energy and apparent modulus. It was found that fatigue crack growth can be altered by the sample shape and production method; however it is also dependent on the chemical composition of the cement. The results revealed that moulded samples, particularly those based on the ASTM F2118 standard, can lead to up to 5.5 times greater fatigue lives compared to the machined samples of the same cement. It is thus essential, when comparing the fatigue results of bone cement, to consider the effect of production method along with the shape of the test sample. PMID:24070780

Sheafi, E M; Tanner, K E

2014-01-01

66

Process to Product.  

ERIC Educational Resources Information Center

Intended for educators who direct federally funded model projects, the booklet provides a framework for special education product development. In "Making Media Decisions," G. Richman explores procedures for selecting the most appropriate medium to carry the message of a given product. The fundamental questions are addressed: what is the goal; who…

Harrison, Gary, Ed.; Mirkes, Donna Z., Ed.

67

Strategic Process And Product Innovation  

Microsoft Academic Search

The study analyzes the timing of process and product innovations. A dynamic product differentiation model illustrates strategic interaction in a duopoly. Firms use asymmetric equilibrium strategies for the adoption of innovations, i.e. innovations are adopted sequentially. The priority of process innovation over product innovation depends on the relative magnitude of the two innovations. Empirical evidence from the semiconductor industry illustrates

Harald Gruber

1995-01-01

68

Anode-support system for the direct electrorefining of cement copper Part II: Process conditions using a circular cell with vertical rotary cathode  

Microsoft Academic Search

This paper describes the second part of a study on the development of a modified anode-support system for the direct electrorefining of cement copper. The proposed system is an alternative process for small mines that produce cement copper after the leaching of copper oxide minerals. It is feasible to utilize a circular cell provided with an annular AISI-316 stainless steel

R. Gana; M. Figueroa; L. Kattan; I. Moller; M. A. Esteso

1995-01-01

69

The Kalina cycle for cement kiln waste heat recovery power plants  

Microsoft Academic Search

Cement production is one of the most energy intensive industrial processes in the world. In many world regions, energy cost is 50% to 60% of the direct production cost of cement. Energy cost is incurred due to the need for large quantities of thermal heat for the kiln, calcination and drying processes and electrical energy for operation of motors for

Mark D. Mirolli

2005-01-01

70

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

71

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

72

Neutron Scattering Studies of Cement  

NASA Astrophysics Data System (ADS)

Despite more than a century of research, basic questions remain regarding both the internal structure and the role of water in Ordinary Portland cement (OPC) concrete, the world's most widely used manufactured material. Most such questions concern the primary hydration product and strength-building phase of OPC paste, the calcium silicate hydrate (C-S-H) gel. When cement and water are mixed, this phase precipitates as clusters of nanoscale (nearly amorphous) colloidal particles with an associated water-filled inter-particle pore system. Most attempts to characterize the C-S-H gel and the behavior of the associated water involve drying or other processes that, themselves, change the bound water content within and around the gel. Neutron scattering methods do not suffer from this disadvantage. Furthermore, the neutron isotope effect and the neutron's sensitivity to molecular motion have enabled considerable progress to be made in recent years by: (i) determining the C-S-H composition, density and gel structure in small-angle neutron scattering (SANS) H/D contrast variation studies; (ii) elucidating the changing state of water within cement as hydration progresses using quasielastic neutron scattering (QENS); and (iii) measuring the production and consumption of nanoscale calcium hydroxide (CH), a by-product of cement hydration that co-exists with the C-S-H gel, using inelastic neutron scattering (INS). These experiments have provided new insights into the physics and chemistry of cement hydration, and have implications for the design of new concretes with pozzolanic cement additions that are intended to address environmental concerns and sustainability issues.

Allen, Andrew

2010-03-01

73

Silicon production process evaluations  

NASA Astrophysics Data System (ADS)

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.

1982-02-01

74

NASA Product Peer Review Process  

NASA Technical Reports Server (NTRS)

This viewgraph presentation describes NASA's product peer review process. The contents include: 1) Inspection/Peer Review at NASA; 2) Reasons for product peer reviews; 3) Different types of peer reviews; and 4) NASA requirements for peer reviews. This presentation also includes a demonstration of an actual product peer review.

Jenks, Ken

2009-01-01

75

The influence of an Austrian fly ash on the reaction processes in the clinker phases of Portland cements  

Microsoft Academic Search

The aim of the paper is to establish the influence of fly ash on the hydration process of the cement and fly ash mixtures.\\u000a Particular attention was paid to the influence on the main clinker phases, C3S, C2S and C3A being investigated by X-ray methods at various points during the reaction period. The reaction partners used were two normal\\u000a Austrian

W. Lukas

1976-01-01

76

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

77

PORE STRUCTURE MODEL OF CEMENT HYDRATES CONSIDERING PORE WATER CONTENT AND REACTION PROCESS UNDER ARBITRARY HUMIDITY  

NASA Astrophysics Data System (ADS)

A simulation model to estimate the pore structure of cement hydrates by curing in arbitrary relative humidity is presented. This paper describes procedures for predicting phase compositions based on the classical hydration model of Portland cement, calculating the particle size distribution of constituent phases and evaluating the pore size distribution by stereological and statistical considerations. And to estimate the water content in pore structure under any relative humidity, we proposed the simulation model of adsorption isotherm model based on the pore structure. To evaluate the effectiveness of this model, simulation results were compared with experimental results of the pore size distribution measured by mercury porosimetry. As a result, it was found that the experimental and simulated results were in close agreement, and the simulated results indicated characterization of the po re structure of cement hydrates.

Fujikura, Yusuke; Oshita, Hideki

78

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

79

Needle coke process and product  

SciTech Connect

A process is disclosed for the production of an improved grade of needle coke employing as a feedstock selected proportions of a pyrolysis furnace oil together with a hydrodesulfurized blend of a clarified oil and a lubricating oil extract.

Eickemeyer, D.B.; Rausch, M.K.; Tollefsen, G.E.

1984-08-21

80

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

81

Case Study of the California Cement Industry  

SciTech Connect

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

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

2005-05-01

82

Fractional factorial design to investigate the influence of heavy metals and anions on acid neutralization behavior of cement-based products.  

PubMed

A major concern of cement-based solidification/stabilization of hazardous wastes is the interaction of waste contaminants on cement properties. Literature contains many examples of studies on the interference of individual contaminants on cement properties. Conversely, little information is available on how the interactions between contaminants affectthe properties of cement/waste systems. This paper provides a discussion on the interference mechanisms exerted by seven contaminants, five heavy metals and two anions, on cement hydration. The seven contaminants were selected on the basis of the typical composition of municipal solid waste incineration (MSWI) fly ash. Spiking experiments using pure compounds were performed according to a 2IV(7-3) fractional factorial design to simulate addition of MSWI fly ash to ordinary Portland cement. The acid neutralization behavior of the laboratory cement-contaminant mixtures was studied to detect the presence of solid phases responsible for the buffering capacity of the solid matrix. The results from the experimental work showed that Zn, Cl-, and SO4(2-) were the major factors influencing, occasionally in combination with other contaminants, strength and acid neutralization capacity of the cementitious products. The release of Cd, Cr, Cu, and Pb in the eluates as a function of pH also suggested possible chemical immobilization mechanisms of such metals within the hardened matrix. PMID:11999070

Polettini, A; Pomi, R; Sirini, P

2002-04-01

83

Energy, environmental and greenhouse gas effects of using alternative fuels in cement production  

E-print Network

.6 million tonnes. 5. A critical review of the literature showed that the dioxin emissions of cement kilns instead of being landfilled. 4. For reasons explained in this report, the maximum amount of EF that can combusting alternative fuels are well below the E.U. and U.S. standards. The case study of Plant 2 showed

Columbia University

84

Metallic aluminum in MSWI fly ash: quantification and influence on the properties of cement-based products.  

PubMed

This article focuses on the effects of metallic aluminum contained in municipal solid waste incineration (MSWI) fly ashes on cement-based materials in which they are added. The ash under study was treated by an industrial physicochemical process of neutralization. The paper also presents a method to quantify the metallic aluminum content of ash: it consists in measuring the amount of hydrogen gas produced by the oxidation reaction of metallic aluminum. This method is simple and fast. Results show that studied ash contains an appreciable amount of metallic aluminum. Investigations were carried out to study the incorporation of the ash in concrete: in this case, the presence of metallic aluminum is worrying because it could be responsible for disorders in concrete. In fact, swellings are observed on cement pastes and mortars containing ash during the first 24 h of hydration. A test based on hydrostatic weighing permits to quantify the swelling of fresh cement paste and to study the evolution of this swelling. Causes of swelling are analyzed. Results show that ettringite formation occurs after the end of the expansion reaction. So it can be concluded that metallic aluminum is the sole responsible for the observed swelling. Consequences of swelling are also analyzed by measuring compressive strength of ash-containing mortars: this swelling leads to cracks in the mortars and significant decrease of their compressive strength. PMID:15219917

Aubert, J E; Husson, B; Vaquier, A

2004-01-01

85

Specific emergy of cement and concrete: An energy-based appraisal of building materials and their transport  

Microsoft Academic Search

Use and production of building materials, such as cement and concrete, is a major cause of global ecological problems with special reference to the overexploitation of non-renewable natural resources due to high temperature production processes, fossil fuels combustion, extraction of raw materials and non-recycling. In this paper, an environmental accounting method was applied to the production of cement and concrete

R. M. Pulselli; E. Simoncini; R. Ridolfi; S. Bastianoni

2008-01-01

86

Bone cement  

PubMed Central

The knowledge about the bone cement is of paramount importance to all Orthopaedic surgeons. Although the bone cement had been the gold standard in the field of joint replacement surgery, its use has somewhat decreased because of the advent of press-fit implants which encourages bone in growth. The shortcomings, side effects and toxicity of the bone cement are being addressed recently. More research is needed and continues in the field of nanoparticle additives, enhanced bone–cement interface etc.

Vaishya, Raju; Chauhan, Mayank; Vaish, Abhishek

2013-01-01

87

The use of by-products from metallurgical and mineral industries as filler in cement-based materials.  

PubMed

This investigation has been made in order to make it possible to increase the use of by-products in cement-based materials. Use of by-products requires a screening procedure that will reliably determine their impact on concrete. A test procedure was developed. The most important properties were considered to be strength development, shrinkage, expansion and workability. The methods used were calorimetry, flow table tests, F-shape measurements, measurements of compressive and flexural strength and shrinkage/expansion measurements. Scanning electron microscopy was used to verify some results. Twelve by-products were collected from Swedish metallurgical and mineral industries and classified according to the test procedure. The investigation showed that the test procedure clearly screened out the materials that can be used in the production of concrete from the unsuitable ones. PMID:12667016

Moosberg, Helena; Lagerblad, Björn; Forssberg, Eric

2003-02-01

88

An extrapolation method for compressive strength prediction of hydraulic cement products  

SciTech Connect

The basis for the AMEBA Method is presented. A strength-time function is used to extrapolate the predicted cementitious material strength for a late (ALTA) age, based on two earlier age strengths--medium (MEDIA) and low (BAIXA) ages. The experimental basis for the method is data from the IPT-Brazil laboratory and the field, including a long-term study on concrete, research on limestone, slag, and fly-ash additions, and quality control data from a cement factory, a shotcrete tunnel lining, and a grout for structural repair. The method applicability was also verified for high-performance concrete with silica fume. The formula for predicting late age (e.g., 28 days) strength, for a given set of involved ages (e.g., 28,7, and 2 days) is normally a function only of the two earlier ages` (e.g., 7 and 2 days) strengths. This equation has been shown to be independent on materials variations, including cement brand, and is easy to use also graphically. Using the AMEBA method, and only needing to know the type of cement used, it has been possible to predict strengths satisfactorily, even without the preliminary tests which are required in other methods.

Siqueira Tango, C.E. de [IPT-Technological Research Inst., Sao Paulo (Brazil)

1998-07-01

89

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

90

NON-PORTLAND CEMENT ACTIVATION OF BLAST FURNACE SLAG  

Microsoft Academic Search

The purpose of this project was to produce a “greener” cement from granulated ground blast furnace slag (GGBS) using non-Portland cement activation. By eventually developing “greener” cement, the ultimate goal of this research project would be to reduce the amount of Portland cement used in concrete, therefore reducing the amount of carbon dioxide emitted into the atmosphere during cement production.

Anne Elizabeth Oberlink

2010-01-01

91

76 FR 12370 - Notice Pursuant to the National Cooperative Research and Production Act of 1993-Portland Cement...  

Federal Register 2010, 2011, 2012, 2013

...LA, and Lehigh Hanson, Inc., Dallas, TX, have been added as parties to this venture. Also, Praxair, Danbury, CT; Metso Minerals, York, PA; Lehigh Cement Company LLC, Allentown, PA; Lehigh Northwest Cement Company, Seattle, WA;...

2011-03-07

92

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

93

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

Microsoft Academic Search

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

Irvin Allen Chen

2009-01-01

94

Recycling of municipal solid waste for cement production: pilot-scale test for transforming incineration ash of solid waste into cement clinker  

Microsoft Academic Search

Incineration ash of municipal solid waste accounts for a great portion of the matter in landfills, and minimization of resource consumption and recycling of waste are important factors for ensuring the future welfare of humankind. The study presented in this paper reports a technology for producing cement from incineration ash of municipal solid waste, incineration ash of sewage sludge and

Ryunosuke Kikuchi

2001-01-01

95

C emQUANT ® software Mathematical modeling in quantitative phase analysis of Portland cement  

Microsoft Academic Search

It is necessary to determine a complete mineralogy of clinker cement to correctly understand, interpret, and predict the outcome of any plant production process. The cement industry's standard method (ASTM C 150) used in quantitative phase analysis of alite, belite, aluminate, and ferrite has long been known to provide approximate concentrations. The wet chemical and optical microscopy methods are too

B. Feret; C. F. Feret

1999-01-01

96

Synthesis: Intertwining product and process  

NASA Technical Reports Server (NTRS)

Synthesis is a proposed systematic process for rapidly creating different members of a program family. Family members are described by variations in their requirements. Requirements variations are mapped to variations on a standard design to generate production quality code and documentation. The approach is made feasible by using principles underlying design for change. Synthesis incorporates ideas from rapid prototyping, application generators, and domain analysis. The goals of Synthesis and the Synthesis process are discussed. The technology needed and the feasibility of the approach are also briefly discussed. The status of current efforts to implement Synthesis methodologies is presented.

Weiss, David M.

1990-01-01

97

Development of high-performance blended cements  

NASA Astrophysics Data System (ADS)

This thesis presents the development of high-performance blended cements from industrial by-products. To overcome the low-early strength of blended cements, several chemicals were studied as the activators for cement hydration. Sodium sulfate was discovered as the best activator. The blending proportions were optimized by Taguchi experimental design. The optimized blended cements containing up to 80% fly ash performed better than Type I cement in strength development and durability. Maintaining a constant cement content, concrete produced from the optimized blended cements had equal or higher strength and higher durability than that produced from Type I cement alone. The key for the activation mechanism was the reaction between added SO4 2- and Ca2+ dissolved from cement hydration products.

Wu, Zichao

2000-10-01

98

Thermodynamics and cement science  

SciTech Connect

Thermodynamics applied to cement science has proved to be very valuable. One of the most striking findings has been the extent to which the hydrate phases, with one conspicuous exception, achieve equilibrium. The important exception is the persistence of amorphous C-S-H which is metastable with respect to crystalline calcium silicate hydrates. Nevertheless C-S-H can be included in the scope of calculations. As a consequence, from comparison of calculation and experiment, it appears that kinetics is not necessarily an insuperable barrier to engineering the phase composition of a hydrated Portland cement. Also the sensitivity of the mineralogy of the AFm and AFt phase compositions to the presence of calcite and to temperature has been reported. This knowledge gives a powerful incentive to develop links between the mineralogy and engineering properties of hydrated cement paste and, of course, anticipates improvements in its performance leading to decreasing the environmental impacts of cement production.

Damidot, D., E-mail: damidot@ensm-douai.fr [Universite Lille Nord de France (France); EM Douai, LGCgE-MPE-GCE, Douai (France); Lothenbach, B. [Empa, Lab. Concrete and Construction Chemistry, Duebendorf (Switzerland); Herfort, D. [Cementir Holding (Denmark); Glasser, F.P. [Chemistry Department, University of Aberdeen, Aberdeen (United Kingdom)

2011-07-15

99

Utilization of industrial waste products as pozzolanic material in cemented paste backfill of high sulphide mill tailings.  

PubMed

In this study, the potential use of the industrial waste products including waste glass (WG), fly ash (FA), granulated blast furnace slag (GBFS) and silica fume (SF) as pozzolanic additive for the partial replacement of ordinary Portland cement (OPC) in cemented paste backfill (CPB) of sulphide-rich mill tailings was investigated. The influence of these industrial waste products on the short- and long-term mechanical performance of CPB was demonstrated. The rate of development of strength of CPB samples tended to slow down when the pozzolanic wastes were incorporated or increased in dosage in the binder phase. Severe losses (by 26%) in the strength of CPB samples produced from exclusively OPC occurred after an initial curing period of 56 days. The addition of WG (10-30 wt%) as a partial replacement of OPC was observed to aggravate further the strength losses of CPB samples. GBFS, FA and SF appeared to improve the long-term performance of CPB samples; albeit, only GBFS and SF could be incorporated into the binder phase only at certain levels i.e. up to 20 wt% GBFS and 15wt% SF in order to maintain a threshold strength level of 0.7MPa over 360 days. SEM studies have provided further insight into the microstucture of CPB and confirmed the formation of deleterious gypsum as the expansive phase. These findings have demonstrated that the industrial waste products including GBFS and SF can be suitably used as mineral additives to improve the long-term mechanical performance of CPB produced from sulphide-rich tailings as well as to reduce the binder costs in a CPB plant. PMID:19299080

Ercikdi, Bayram; Cihangir, Ferdi; Kesimal, Ayhan; Deveci, Haci; Alp, Ibrahim

2009-09-15

100

The processing, properties, and applications of calcium aluminate–phenol resin composite 1 1 This paper was originally submitted to Advanced Cement Based Materials on 15 October 1997 and accepted on 22 March 1998. The paper was received at the Editorial Office of Cement and Concrete Research on 20 August 1998 and accepted in final form on 14 September 1998  

Microsoft Academic Search

The processing, properties, and a few applications of calcium aluminate–phenol resin composite with very high flexural strength are discussed. This composite contains a very large amount of cement (70 vol%) but shows unusual engineering properties, which have not yet been achieved by traditional cement-based materials. The flexural strength of the composite is found to be 120 to 220 MPa; in

G. K. Dinilprem Pushpalal; Tadashi Kobayashi; Toshio Kawano; Naomi Maeda

1999-01-01

101

Corrosion of Aluminium in Composite Cements Anthony Setiadi* and Neil B. Milestone  

E-print Network

A composite cement is a hydraulic cement composed of Portland cement and one or more inorganic materials products have any effects on the cement durability and phases formed in cement. Current work has involvedCorrosion of Aluminium in Composite Cements Anthony Setiadi* and Neil B. Milestone Immobilisation

Sheffield, University of

102

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

103

Research of magnesium phosphosilicate cement  

NASA Astrophysics Data System (ADS)

Magnesium phosphosilicate cement (MPSC) is a novel phosphate bonded cement, which consists mainly of magnesia, phosphate and silicate minerals. The traditional magnesium phosphate cements (MPCs) usually composed by ammonium phosphate, and gaseous ammonia will emit during mixing and in service. There is no noxious ammonia released from MPSC, furthermore, it can recycle a large volume of the non-hazardous waste. The goal of this research is to investigate the composition, reaction products, reaction mechanism, microstructure, properties, durability and applications of the MPSC. MPSC sets rapidly and has high early strength. It reacts better with solid industrial waste when compared to Portland cement. Many solid industrial wastes, such as fly ash, steel slag, coal gangue, red coal gangue, red mud, barium-bearing slag, copper slag, silica fume, and ground granulated blast furnace slag, have been used as the main component (40% by weight) in MPSC. The research has found that these aluminosilicate (or ironsilicate, or calciumsilicate) minerals with an amorphous or glass structure can enhance the performance of MPSC. The disorganized internal structure of amorphous materials may make it possess higher reactivity compared to the crystalline phases. Chemical reaction between phosphate and these minerals may form an amorphous gel, which is favorable to the cementing. Borax, boric acid and sodium tripolyphosphate have been used as retardants in the MPSC system. It is found that boric acid has a higher retarding effect on the setting of cement, than borax does. However, sodium polyphosphate accelerates the reaction of MPSC. The hydration of MPSC is exothermic reaction. The heat evolution may prompt hydrates formation, and shorten the setting process. Modern materials characterization techniques, XRD, DSC, TG-DTA FTIR, XPS, MAS-NMR, SEM, TEM, MIP, etc. were used to analyze the phase composition, micro morphology, and microstructure of hardened MPSC. The main hydration product in MPSC is MgKPO4·6H2O (MKP), which has both crystalline and amorphous phases. There are many unreacted magnesia grains in the hardened MPSC paste. They act as nucleus of the hardened framework. The hydrates grow around the magnesia grains rims, fill in the voids among the magnesia grains and bond unreacted magnesia part into a solid continuum. (Abstract shortened by UMI.)

Ding, Zhu

104

Injectable bone cement based on mineralized collagen.  

PubMed

A novel injectable bone cement based on mineralized collagen was reported in this paper. The cement was fabricated by introducing calcium sulfate hemihydrate (CaSO(4).1/2H(2)O, CSH) into nano-hydroxyapatite/collagen (nHAC). The workability, in vitro degradation, in vitro and in vivo biocompatibility of the cement (nHAC/CSH) were studied. The comparative tests via in vitro and in vivo showed that the nHAC/CSH composite cement processed better biocompatibiltiy than that of pure CSH cement. The results implied that this new injectable cement should be very promising for bone repair. PMID:20336741

Liu, Xi; Wang, Xiu-Mei; Chen, Zonggang; Cui, Fu-Zhai; Liu, Huan-Ye; Mao, Keya; Wang, Yan

2010-07-01

105

Wood Technology: Techniques, Processes, and Products  

ERIC Educational Resources Information Center

Seven areas of wood technology illustrates applicable techniques, processes, and products for an industrial arts woodworking curriculum. They are: wood lamination; PEG (polyethylene glycol) diffusion processes; wood flour and/or particle molding; production product of industry; WPC (wood-plastic-composition) process; residential construction; and…

Oatman, Olan

1975-01-01

106

Solidification/stabilization of Cr(VI) with cement leachability and XRD analyses[X-Ray Diffraction  

SciTech Connect

The leachability of Cr(VI) from solidified Cr(VI)-Portland cement mixtures cured for 28 days were investigated. Cr(VI) was solidified with Type 1 Portland cement at concentrations of 0.5%, 2%, and 5% (based on K{sub 2}CrO{sub 4}) by weight of the cement. The addition of Cr(VI) increased the initial and final setting times of cement. X-ray diffraction (XRD) study indicates that Cr(VI) inhibits cement hydration process by reacting with Ca{sup 2+} during the hydration of cement, which was also supported by increased setting times. Increasing the Cr(VI) content in the cement reduced the compressive strength of the solidified cement. The leachability of Cr(VI) during the toxicity characteristics leaching procedures (TCLP) test was dependent on the initial Cr(VI) concentration and the leaching time. The treatment efficiency of cement was independent of the initial Cr(VI) concentration. The reaction products and crystalline phases were identified using the XRD. One of the reaction products identified was CaCrO{sub 4}. An empirical relationship was developed to predict the leaching of Cr(VI). Based on this relationship, the treatable amount should be limited to K{sub 2}CrO{sub 4}/cement ratio of 0.2% to meet the TCLP limit of 5 mg/l.

Wang, S.; Vipulanandan, C.

2000-03-01

107

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

108

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

2012-01-01

109

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

110

A comparative study of ordinary and mineralised Portland cement clinker from two different production units Part I: Composition and hydration of the clinkers  

SciTech Connect

Portland cement clinkers from two production units were investigated; Plant 1: ordinary clinker (P1) and clinker mineralised with CaF{sub 2}+CaSO{sub 4} (P1m); Plant 2: ordinary clinker (P2) and two clinkers mineralised with CaF{sub 2}+CaSO{sub 4} (P2m, low SO{sub 3} and P2m', high SO{sub 3}). The chemical composition of the clinkers was determined by X-ray fluorescence, ICP analysis, titration (free lime) and ion selective electrode measurements (F). Observed clinker parameters (LSF, SR, AR, R, wt.% MgO, F, SO{sub 3}, free lime): P1 (0.96, 2.72, 1.27, 1.04, 0.78, 0.06, 0.64, 0.71); P1m (1.03, 2.21, 1.58, 2.18, 0.87, 0.23, 1.95, 0.69); P2 (1.00, 2.66, 1.72, 0.75, 4.06, 0.20, 1.38, 1.51); P2m (1.01, 2.91, 1.96, 0.90, 3.21, 0.39, 1.72, 2.06); P2m' (0.97, 2.70, 1.84, 1.15, 3.86, 0.42, 2.48, 0.89). The qualitative and quantitative phase compositions were characterised using X-ray powder diffraction, backscattered electron imaging, X-ray microanalysis and elemental mapping, plus optical reflection microscopy. Phases observed in all clinkers were: alite, {beta}-belite, cubic aluminate, ferrite and free lime. Additional phases observed were: aphthitalite (P1, P2, P2m, P2m'), calcium langbeinite (P1m) and periclase (P2, P2m, P2m'). The clinker composition and texture differ more between the two plants, than between ordinary and mineralised clinker from the same production unit. Laboratory cements were prepared by mixing ground clinker with CaSO{sub 4}{center_dot}2H{sub 2}O. The cements were hydrated in an isothermal calorimeter at 20 deg. C (water/cement weight ratio=0.5) during 33 h. After 12 h, the laboratory cement based on P1m reached a higher level of reaction than the one based on P1. The P2m and P2m' laboratory cements had a slower reaction than the P2 cement.

Emanuelson, Anna; Hansen, Staffan; Viggh, Erik

2003-10-01

111

Process for capturing CO2 arising from the calcination of the CaCO3 used in cement manufacture.  

PubMed

This paper outlines a new CaCO3 calcination method for producing a stream of CO2 (suitable for permanent geological storage after purification and compression). The process is based on the use of very hot CaO particles (T >1000 degrees C) to transfer heat from a circulating fluidized bed combustor (CFBC) to a calciner (fluidized with CO2 and/or steam). Since the fluidized bed combustor and calciner have separate atmospheres, the CO2 resulting from the decomposition of CaCO3 can be captured, while the CO2 generated in the combustion of the fuel in air is emitted to the atmosphere. We demonstrate that with this system it is possible to reduce the CO2 emissions of a cement plant by around 60%. Furthermore, since the key pieces of equipment are similar to the commercial CFBCs used in power generation plants, it is possible to establish the additional investment required for the system and to estimate the cost per ton of CO2 avoided for this process to be about 19 $/tCO2 avoided. PMID:18853819

Rodríguez, N; Alonso, M; Grasa, G; Abanades, J Carlos

2008-09-15

112

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.

113

Cement-based thermocouples  

Microsoft Academic Search

A cement-based thermocouple in the form of a junction between dissimilar cement pastes and exhibiting thermocouple sensitivity 70±7 ?V\\/°C is provided. The dissimilar cement pastes are steel fiber cement paste (n-type) and carbon-fiber silica-fume cement paste (p-type). The junction is made by pouring the cement pastes side by side.

Sihai Wen; D. D. L. Chung

2001-01-01

114

Effect of temperature on the hydration of the main clinker phases in portland cements: part ii, blended cements  

Microsoft Academic Search

The hydration of three blended cements, i.e., Portland cement blended with GGBFS, PFA, and volcanic ash, based on two neat cements investigated previously, has been followed at five temperatures ranging from 10°C to 60°C. The cements were cured under water and tested at various time intervals over a period of one year. The hydration products were characterised by means of

J. I. Escalante-Garc??a; J. H. Sharp

1998-01-01

115

Comparison of the characteristic leaching behavior of cements using standard (EN 196-1) cement mortar and an assessment of their long-term environmental behavior in construction products during service life and recycling  

Microsoft Academic Search

The uncertain environmental properties of cements, when used in construction materials, during these materials' service life and any “secondary life” (construction debris), have been raised as matters of concern due to the increasing use of alternative fuels and raw materials in the manufacture of cement clinker. A comparison of the leaching behavior of a range of traditional cement types, assessed

H. A van der Sloot

2000-01-01

116

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

117

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

118

Sulfoaluminate-belite cement from low-calcium fly ash and sulfur-rich and other industrial by-products  

SciTech Connect

The study describes the preparation and characterization of an environmentally friendly cement with performance characteristics similar to those of Portland cement, from a lime kiln bag house dust, a low-calcium fly ash, and a scrubber sludge. Promising preliminary results show the formation of relatively low-temperature phases calcium sulfoaluminate (4CaO{center{underscore}dot}3Al{sub 2}O{sub 3}{center{underscore}dot}SO{sub 3}) and dicalcium silicate (2CaO{center{underscore}dot}SiO{sub 2}) at {approximately} 1,250 C if nodulized raw means used for clinker preparation and at 1,175 C if powdered raw meal is used as compared to the {approximately} 1,500 C sintering temperature required for Portland cement. Phases of the developed cements were predicted using modified Bogue calculations. Isothermal calorimetric measurements indicate the hydration properties of the cements are comparable to ordinary Portland cement. Mechanical properties and microstructural evaluations also were carried out.

Arjunan, P.; Silsbee, M.R.; Roy, D.M.

1999-08-01

119

Energy-saving cements obtained from chemical gypsum and other industrial wastes  

SciTech Connect

The main sources, properties and uses of chemical gypsum are reviewed and the possibility of its utilization for the manufacturing process of calcium sulfoaluminate cements is explored. In this process other industrial wastes, as sources of reactive silica and alumina, can be employed. Phosphogypsum, blast-furnace slag and fly ash were the main by-products investigated. The principal properties of calcium sulfoaluminate cements, such as synthesis, hydration and strength, were discussed. Some durability problems and suggested solutions were particularly emphasized.

Beretka, J. [CSIRO Div. of Building, Construction and Engineering, Highett, Victoria (Australia)] [CSIRO Div. of Building, Construction and Engineering, Highett, Victoria (Australia); Cioffi, R. [Univ. Degli Studi di Napoli Federico II (Italy). Dipt. di Ingegneria dei Materiali e della Produzione] [Univ. Degli Studi di Napoli Federico II (Italy). Dipt. di Ingegneria dei Materiali e della Produzione; Marroccoli, M.; Valenti, G.L. [Univ. della Basilicata, Potenza (Italy). Dipt. di Ingegneria e Fisica dell`Ambiente] [Univ. della Basilicata, Potenza (Italy). Dipt. di Ingegneria e Fisica dell`Ambiente

1996-12-31

120

An Integrated Process and Product Model  

Microsoft Academic Search

The relationship between product quality and process capability and maturity has been recognized as a major issue in software engineering based on the premise that improvements in process will lead to higher quality products. To this end, we have been investigating an important facet of process capability, stability, as defined and evaluated by trend, change, and shape metrics, across releases

Norman F. Schneidewind

1998-01-01

121

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

122

EFFECT OF PORTLAND CEMENT ON STRENGTH DEVELOPMENT OF PHOSPHOANHYDRITE-POZZOLANA CEMENT  

Microsoft Academic Search

The paper is a part of the research on a complex alternative technology of apatite phosphogypsum (PG) obtained during the production of phosphoric acid from Kola apatite, on rare earth concentrate and phosphoanhydrite cement with the recovery of phosphate compounds. The effect of Portland cement on mechanical properties of phosphoanhydrite-pozzolana cement has been determined. The samples of binder were prepared

Andrzej JAROSIÑSKI

1997-01-01

123

Productivity enhancement through process integration  

E-print Network

between reactor yield and process yield???????????????????????.. 3 2.1 Graphical representation of the HEN synthesis task????????. 9 2.2 Graphical representation of single mass exchanger????...???? 12 2.3 Mass Exchange Network (MEN... 2.7 Graphical representation of HIWAMIN and EIWAMIN synthesis??.. 18 4.1 General process scheme to differentiate between reactor yield and process yield???????????????????????.. 47 4.2a Evaluating feed to reactor...

Alotaibi, Meteab Aujian

2006-10-30

124

Reduction of NO{sub x} emissions from cement kiln/calciner through the use of the NO{sub x}OUT process  

SciTech Connect

The post combustion reduction of NO{sub x} using urea has proven to be an effective method in controlling NO{sub x} from various combustion sources. This process, a selective non-catalytic reduction process known as NO{sub x}OUT, has been successfully demonstrated in a cement kiln/calciner operated by Ash Grove Cement. Testing was done under ten different kiln/calciner operating conditions. Using three to four injectors, NO{sub x} was efficiently reduced from 350--600 pounds per hour (3.5--6.0 lb/ton of clinker) to less than 100 pounds per hour (1.0 lb/ton of clinker). This calculates to a NO{sub x} reduction of > 80% for most cases. Chemical utilization was greater than 50%. A high degree of mixing and a long residence time at an appropriate temperature present in the preheater tower contributed to these excellent results. An average ammonia slip was four ppm above a baseline level at normalized stoichiometric ratio of 1. Based on this demonstration, cement kiln/calciners have been identified as an ideal application for the NO{sub x}OUT Process. NO{sub x} was efficiently and effectively reduced with minimal byproduct emissions and virtually no effect on plant operations.

Sun, W.H. [Nalco Fuel Tech., Naperville, IL (United States); Bisnett, M.J.; Kirk, D.W. [Nalco Fuel Tech, Santa Fe Springs, CA (United States); Steuch, H.E. [Ash Grove Cement Co., Portland, OR (United States); Hille, J. [Ash Grove Cement Co., Seattle, WA (United States)

1994-12-31

125

EFL Writing: Product and Process.  

ERIC Educational Resources Information Center

This paper presents a cyclical framework of teaching procedures for a comprehensive English-as-a-Foreign Language writing program. It begins by providing examples of Greek students' writing and identifying common programs. Next, it outlines two aspects of good writing: product (language, layout and organization, relevance to the task, regard for…

Gabrielatos, Costas

126

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

127

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

128

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...

129

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

130

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

131

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

132

Effects of cement particle size distribution on performance properties of Portland cement-based materials  

SciTech Connect

The original size, spatial distribution, and composition of Portland cement particles have a large influence on hydration kinetics, microstructure development, and ultimate properties of cement-based materials. In this paper, the effects of cement particle size distribution on a variety of performance properties are explored via computer simulation and a few experimental studies. Properties examined include setting time, heat release, capillary porosity percolation, diffusivity, chemical shrinkage, autogenous shrinkage, internal relative humidity evolution, and interfacial transition zone microstructure. The effects of flocculation and dispersion of the cement particles in the starting microstructures on resultant properties are also briefly evaluated. The computer simulations are conducted using two cement particle size distributions that bound those commonly in use today and three different water-to-cement ratios: 0.5, 0.3, and 0.246. For lower water-to-cement ratio systems, the use of coarser cements may offer equivalent or superior performance, as well as reducing production costs for the manufacturer.

Bentz, D.P.; Garboczi, E.J.; Haecker, C.J.; Jensen, O.M.

1999-10-01

133

Narrative Infrastructure in Product Creation Processes  

Microsoft Academic Search

In product creation processes, perhaps even more than in organization processes in general, uncertainties are addressed and complexity is reduced. In retrospect, linearized success stories are told. The history of a product innovation in a biotechnology firm is used to show how actually, over time, attributions and typifications in stories, and the implied stories contained in interactions, link up and

J. Jasper Deuten; Arie Rip

2000-01-01

134

Glass powder blended cement hydration modelling  

NASA Astrophysics Data System (ADS)

The use of waste materials in construction is among the most attractive options to consume these materials without affecting the environment. Glass is among these types of potential waste materials. In this research, waste glass in powder form, i.e. glass powder (GP) is examined for potential use in enhancing the characteristics of concrete on the basis that it is a pozzolanic material. The experimental and the theoretical components of the work are carried out primarily to prove that glass powder belongs to the "family" of the pozzolanic materials. The chemical and physical properties of the hydrated activated glass powder and the hydrated glass powder cement on the microstructure level have been studied experimentally and theoretically. The work presented in this thesis consists of two main phases. The first phase contains experimental investigations of the reaction of glass powder with calcium hydroxide (CH) and water. In addition, it includes experiments that are aimed at determining the consumption of water and CH with time. The reactivity, degree of hydration, and nature of the pore solution of the glass powder-blended cement pastes and the effect of adding different ratios of glass powder on cement hydration is also investigated. The experiments proved that glass powder has a pozzolanic effect on cement hydration; hence it enhances the chemical and physical properties of cement paste. Based on the experimental test results, it is recommended to use a glass powder-to-cement ratio (GP/C) of 10% as an optimum ratio to achieve the best hydration and best properties of the paste. Two different chemical formulas for the produced GP C-S-H gel due to the pure GP and GP-CH pozzolanic reaction hydration are proposed. For the pure GP hydration, the produced GP C-S-H gel has a calcium-to-silica ratio (C/S) of 0.164, water-to-silica ratio (H/S) of 1.3 and sodium/silica ratio (N/S) of 0.18. However, for the GP-CH hydration, the produced GP C-S-H gel has a C/S ratio of 1.17, H/S ratio of 2.5 and N/S ratio of 0.18. In the second phase of this research, theoretical models are built using a modified version of an existing cement hydration modelling code, "CEMHYD3D", to simulate the chemical reaction of the activated glass powder hydration and glass powder in cement. The modified model, which is referred to as the "MOD-model" is further used to predict the types, compositions and quantities of reaction products. Furthermore, the glass powder hydration data, which is obtained experimentally, is incorporated into the MOD-model to determine the effect of adding glass powder to the paste on the process of cement hydration and resulting paste properties. Comparisons between theoretical and experimental results are made to evaluate the developed models. The MOD-model predictions have been validated using the experimental results, and were further used to investigate various properties of the hydrated glass powder cement paste. These properties include, for example, CH content of the paste, porosity, hydration degree of the glass powder and conventional C-S-H and GP CS-H contents. The results show that the MOD-model is capable of accurately simulating the hydration process of glass powder-blended cement paste and can be used to predict various properties of the hydrating paste.

Saeed, Huda

135

Strength development, hydration reaction and pore structure of autoclaved slag cement with added silica fume  

SciTech Connect

Under continuous hydrothermal treatment the strength of portland cement paste decreases with curing time and the pore structure coarsens. It was found in this study that the compressive strength of slag cement paste containing 67.5 wt.% ggbfs also decreases with time after 24 hour hydrothermal processing, but with a small addition of silica fume to the slag cement, the cement strength increases and the pore structure densifies when processed under comparable conditions. Based on observations XRD and SEM, these changes are attributed to: (1) changes in the hydration reactions and products by highly reactive silica fume, such that amorphous products dominate and the strength reducing phase {alpha}-C{sub 2}SH does not form; (2) slower hydration of slag, partially caused by the decreased pH of the pore solution, favors the formation of a dense pore structure; and (3) the space filling properties of the micro particles of silica fume.

Xi, Y. [China Building Materials Academy, Beijing (China)] [China Building Materials Academy, Beijing (China); Siemer, D.D. [LITCO, Idaho Falls, ID (United States)] [LITCO, Idaho Falls, ID (United States); Scheetz, B.E. [Pennsylvania State Univ., University Park, PA (United States). Materials Research Lab.] [Pennsylvania State Univ., University Park, PA (United States). Materials Research Lab.

1997-01-01

136

Rheology of foamed cement  

Microsoft Academic Search

Foams are being used in a number of petroleum industry applications that exploit their high viscosity and low density. Foamed cement slurries can have superior displacement properties relative to non-foamed cement slurries. This article presents results of an experimental study of foamed cement rheology. Viscosity curves of foamed cements were obtained using a flow-through rotational viscometer. Foamed cements with different

R. M. Ahmed; N. E. Takach; U. M. Khan; S. Taoutaou; S. James; A. Saasen; R. Godøy

2009-01-01

137

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

138

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.

Pal, Uday B. (Malden, MA); Gazula, Gopala K. M. (Somerville, MA); Hasham, Ali (Karachi, PK)

1996-01-01

139

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

140

Effect of Cr 2O 3 and NiO additions on the phase transformations at high temperature in Portland cement  

Microsoft Academic Search

Although there exists much work to characterize the effect of minor elements on the properties of Portland cement, the same is not valid for the knowledge about their impact on the clinkering process. The goal of this work is to study the effects of chromium and nickel oxide additions on the transformations during the production of Portland cement clinker. The

A. M. Barros; D. C. R. Espinosa; J. A. S. Tenório

2004-01-01

141

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. PMID:24843401

2014-01-01

142

A cement kiln flue-dust evaluated as a soil liming material  

E-print Network

Cement Kiln Flue-duet Evaluated as a Soil Liming Material. (May 1973) Raimund Stacha, B. S. , Texas A&M University Directed by: Dr. Warren B. Anderson During the process of cement production, limestone, iron ore, oyster shells and clay are ground... in the vicinity of the source of the material (10, 12, 56, 57). Whittaker, Erickson, Love, and Carroll (56) determined that three cement kiln flue-dusts in the Maryland area had about the same soil liming qualities as pulverised limestone. Carroll, Erickson...

Stacha, Raimund

2012-06-07

143

Investigation of fatigue crack growth in acrylic bone cement using the acoustic emission technique  

Microsoft Academic Search

Failure of the bone cement mantle has been implicated in the loosening process of cemented hip stems. Current methods of investigating degradation of the cement mantle in vitro often require sectioning of the sample to confirm failure paths. The present research investigates acoustic emission as a passive experimental method for the assessment of bone cement failure. Damage in bone cement

A. Roques; M. Browne; J. Thompson; C. Rowland; A. Taylor

2004-01-01

144

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

145

Advanced Multi-Product Coal Utilization By-Product Processing Plant  

SciTech Connect

The overall objective of this project is to design, construct, and operate an ash beneficiation facility that will generate several products from coal combustion ash stored in a utility ash pond. The site selected is LG&E's Ghent Station located in Carroll County, Kentucky. The specific site under consideration is the lower ash pond at Ghent, a closed landfill encompassing over 100 acres. Coring activities revealed that the pond contains over 7 million tons of ash, including over 1.5 million tons of coarse carbon and 1.8 million tons of fine (<10 {micro}m) glassy pozzolanic material. These potential products are primarily concentrated in the lower end of the pond adjacent to the outlet. A representative bulk sample was excavated for conducting laboratory-scale process testing while a composite 150 ton sample was also excavated for demonstration-scale testing at the Ghent site. A mobile demonstration plant with a design feed rate of 2.5 tph was constructed and hauled to the Ghent site to evaluate unit processes (i.e. primary classification, froth flotation, spiral concentration, secondary classification, etc.) on a continuous basis to determine appropriate scale-up data. Unit processes were configured into four different flowsheets and operated at a feed rate of 2.5 tph to verify continuous operating performance and generate bulk (1 to 2 tons) products for product testing. Cementitious products were evaluated for performance in mortar and concrete as well as cement manufacture process addition. All relevant data from the four flowsheets was compiled to compare product yields and quality while preliminary flowsheet designs were generated to determine throughputs, equipment size specifications and capital cost summaries. A detailed market study was completed to evaluate the potential markets for cementitious products. Results of the study revealed that the Ghent local fly ash market is currently oversupplied by more than 500,000 tpy and distant markets (i.e. Florida) are oversupplied as well. While the total US demand for ultrafine pozzolan is currently equal to demand, there is no reason to expect a significant increase in demand. Despite the technical merits identified in the pilot plant work with regard to beneficiating the entire pond ash stream, market developments in the Ohio River Valley area during 2006-2007 were not conducive to demonstrating the project at the scale proposed in the Cooperative Agreement. As a result, Cemex withdrew from the project in 2006 citing unfavorable local market conditions in the foreseeable future at the demonstration site. During the Budget Period 1 extensions provided by the DOE, CAER has contacted several other companies, including cement producers and ash marketing concerns for private cost share. Based on the prevailing demand-supply situation, these companies had expressed interest only in limited product lines, rather than the entire ash beneficiation product stream. Although CAER had generated interest in the technology, a financial commitment to proceed to Budget Period 2 could not be obtained from private companies. Furthermore, the prospects of any decisions being reached within a reasonable time frame were dim. Thus, CAER concurred with the DOE to conclude the project at the end of Budget Period 1, March 31, 2007. The activities presented in this report were carried out during the Cooperative Agreement period 08 November 2004 through 31 March 2007.

Thomas Robl; John Groppo

2009-06-30

146

Radon exhalation of cementitious materials made with coal fly ash: Part 2--testing hardened cement-fly ash pastes.  

PubMed

Increased interest in measuring radionuclides and radon concentrations in fly ash (FA), cement and other components of building products is due to the concern about health hazards of naturally occurring radioactive materials (NORM). The paper focuses on studying the influence of FA on radon exhalation rate (radon flux) from cementitious materials. In the previous part of the paper the state of the art was presented, and the experiments for testing raw materials, Portland cement and coal fly ash, were described. Since the cement and FA have the most critical role in the radon release process relative to other concrete constituents (sand and gravel), and their contribution is dominant in the overall radium content of concrete, tests were carried out on cement paste specimens with different FA contents, 0-60% by weight of the binder (cement+FA). It is found that the dosage of FA in cement paste has a limited influence on radon exhalation rate, if the hardened material is relatively dense. The radon flux of cement-FA pastes is lower than that of pure cement paste: it is about approximately 3 mBq m(-2) s(-1) for cement-FA pastes with FA content as high as 960 kg m(-3). PMID:15885379

Kovler, K; Perevalov, A; Levit, A; Steiner, V; Metzger, L A

2005-01-01

147

Product Development Processes, Three Vectors Of Improvement  

E-print Network

Product Development Processes have achieved a state of some maturity in recent years, but have focused primarily on structuring technical activities from the initiation of development to launch. We advocate major advances ...

Holmes, Maurice

2003-01-01

148

The non-productive entrepreneurial process  

Microsoft Academic Search

A large literature explores the importance of entrepreneurship as the catalyst of economic progress. In contrast, this paper\\u000a argues that entrepreneurs are the driver of economic stagnation. We analyze the non-productive entrepreneurial process and\\u000a discuss three channels through which non-productive activities have a multiplier effect culminating in economic decline and\\u000a stagnation. Drawing on examples of non-productive entrepreneurship from both underdeveloped

Christopher J. Coyne; Russell S. Sobel; John A. Dove

2010-01-01

149

Benchmarking Peer Production Mechanisms, Processes & Practices  

ERIC Educational Resources Information Center

This deliverable identifies key approaches for quality management in peer production by benchmarking peer production practices and processes in other areas. (Contains 29 footnotes, 13 figures and 2 tables.)[This report has been authored with contributions of: Kaisa Honkonen-Ratinen, Matti Auvinen, David Riley, Jose Pinzon, Thomas Fischer, Thomas…

Fischer, Thomas; Kretschmer, Thomas

2008-01-01

150

A corporate product integrity assurance process.  

PubMed

One of the more difficult challenges that confronts the chemical industry throughout the industrialized world is how to effectively manage the various and often diverse regulatory requirements. What follows is a description of a process designed to help with new product introductions. The process is generic and is applicable to almost any corporate environment and structure. PMID:1669968

Weiler, E D; Keener, R

1991-10-01

151

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

PubMed

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 (C3S) 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+ attacks on cement phases and the precipitation of calcium heavy metal double hydroxides, which consumes calcium ions and then promotes the decomposition of C3S. In this work, molecular models of calcium silicate hydrate gel are presented based on the examination of 29Si 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. PMID:18367391

Chen, Q Y; Tyrer, M; Hills, C D; Yang, X M; Carey, P

2009-01-01

152

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

153

Production Process Characterization (Engineering Statistics Handbook)  

NSDL National Science Digital Library

Created by Alan Heckert and James Filliben, this chapter of the National Institute of Standards and Technology (NIST) Engineering Statistics handbook describes how to do a production process characterization study. It contains an introduction, discussion of the assumptions, information about data collection and analysis, and case studies. The author provides two different case studies and states that: "The accompanying case studies provide detailed examples of several process characterization studies." This is a nice introduction to theories of production process and then direct applications of these theories.

Filliben, James; Heckert, Alan

2009-02-16

154

In-vitro Comparison of the Antimicrobial Properties of Glass Ionomer Cements with Zinc Phosphate Cements  

PubMed Central

White spot lesions are observed in nearly 50% of patients undergoing orthodontic treatment. Long-lasting antibacterial properties of orthodontic cements can reduce this phenomenon. The aim of this research was to compare antimicrobial activity of three commercial glass ionomer cements with three commercial zinc phosphate cements, over time, against streptococcus mutans and candida albicans. Direct contact test (DCT) was used to evaluate the antibacterial and antifungal activity of products after 48 h and 7 days of incubation. The results demonstrated that all the cements presented antibacterial activity but the antibacterial activity of glass ionomer cements was more than that of zinc phosphate cements. Counts of C. albicans after 48 h were lower and statistically different in the GIC group in relation to the control groups. But no differences were observed between GIC and control groups at 7 days. Based on the results of this study, the antimicrobial and mainly antifungal effects of all the cements were so short.

Vahid Dastjerdie, Elaheh; Oskoui, Mahvash; Sayanjali, Elham; Tabatabaei, Fahimeh Sadat

2012-01-01

155

Effect of aluminium phosphate as admixture on oxychloride cement  

Microsoft Academic Search

The effect of admixing of aluminium phosphate on oxychloride cement in the matrix has been investigated. It is shown that\\u000a aluminium phosphate retards the setting process of the cement and improves water-tightness.

M. P. S. Chandrawat; R. N. Yadav

2000-01-01

156

Well cementing in permafrost  

SciTech Connect

A process for cementing a string of pipe in the permafrost region of a borehole of a well wherein aqueous drilling fluid actually used in drilling the wellbore in the permafrost region of a wellbore is employed. The drilling fluid contains or is adjusted to contain from about 2 to about 16 volume percent solids. Mixing with the drilling fluid (1) an additive selected from the group consisting of ligno-sulfonate, lignite, tannin, and mixtures thereof, (2) sufficient base to raise the pH of the drilling fluid into the range of from about 9 to about 12, and (3) cementitious material which will harden in from about 30 to about 40 hours at 40/sup 0/F. The resulting mixture is pumped into the permafrost region of a wellbore to be cemented and allowed to harden in the wellbore. There is also provided a process for treating an aqueous drilling fluid after it has been used in drilling the wellbore in permafrost, and a cementitious composition for cementing in a permafrost region of a wellbore.

Wilson, W.N.

1980-01-01

157

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 was performed to analyze the alkali-silica reactivity of ULHS in cement slurries.

Fred Sabins

2002-07-30

158

Developme nt strategies for foamed cement paste  

Microsoft Academic Search

For several decades numerous research projects dealt with foamed concret e. Although foamed cement-bound materials have very useful properties, for example low density and low thermal conductivity, they are not often used as construction material, because predefined properties are difficult to attain accu- rately. Therefore the intention of this research work is the unerring production of cement-bound foams. Based on

J. U. Pott

2002-01-01

159

Process for the production of fine chemicals  

US Patent & Trademark Office Database

The present invention relates to a process for the production of fine chemicals in a microorganism, a plant cell, a plant, a plant tissue or parts thereof by increasing or generating the biological activity of a ras-Like GTPase or the homologues thereof and growing the organism under conditions which permit the production of the fine chemicals in the organism. Preferred fine chemicals produced by the present invention include amino acids, carbohydrates, vitamins, fatty acids, and carotenoids.

2011-08-30

160

Improving efficiency in product and process development : a case study on a consumer products creation process  

E-print Network

This research examines how an athletic footwear company should establish its new product development and launch process to eliminate wastes in the processes and improve the time to market. Currently, it typically takes an ...

Dong, Xiaoqin, 1971-

2004-01-01

161

Process redesign of production maintenance operations  

SciTech Connect

This paper describes a methodology for the systematic redesign of traditional production maintenance operations as they relate to subsurface failures of sucker rod pumped wells. The paper advocates an organized approach to process definition, refinement and redesign such that improvement objectives are clearly communicated, appropriate human and physical resources are brought to bear, and a system of improvement measurements becomes the overriding focus of the operation. Specific examples of the use of statistical process control tools in the production maintenance quality improvement effort are explored.

Rankin, M.; Lowe, B.; Disney, V. Spilman, K.

1995-12-31

162

48 CFR 870.111-5 - Frozen processed food products.  

Code of Federal Regulations, 2011 CFR

...products that contain fish or fish products. (3) Frozen bakery products. (b) All procured frozen processed food products...issued to accompany the shipment. (d) Producers of frozen bakery products that ship products in interstate commerce are...

2011-10-01

163

48 CFR 870.111-5 - Frozen processed food products.  

Code of Federal Regulations, 2013 CFR

...products that contain fish or fish products. (3) Frozen bakery products. (b) All procured frozen processed food products...issued to accompany the shipment. (d) Producers of frozen bakery products that ship products in interstate commerce are...

2013-10-01

164

48 CFR 870.111-5 - Frozen processed food products.  

Code of Federal Regulations, 2010 CFR

...products that contain fish or fish products. (3) Frozen bakery products. (b) All procured frozen processed food products...issued to accompany the shipment. (d) Producers of frozen bakery products that ship products in interstate commerce are...

2010-10-01

165

48 CFR 870.111-5 - Frozen processed food products.  

Code of Federal Regulations, 2012 CFR

...products that contain fish or fish products. (3) Frozen bakery products. (b) All procured frozen processed food products...issued to accompany the shipment. (d) Producers of frozen bakery products that ship products in interstate commerce are...

2012-10-01

166

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

167

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

168

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

169

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

170

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

171

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

172

Prospects of solar thermal hydrogen production processes  

Microsoft Academic Search

This article provides a critical discussion of prospects of solar thermal hydrogen production in terms of technological and economic potentials and their possible role for a future hydrogen supply. The study focuses on solar driven steam methane reforming, thermochemical cycles, high temperature water electrolysis and solar methane cracking. Development status and technological challenges of the processes and objectives of ongoing

Thomas Pregger; Daniela Graf; Wolfram Krewitt; Christian Sattler; Martin Roeb; Stephan Möller

2009-01-01

173

Workplace exposure at nanomaterial production processes  

NASA Astrophysics Data System (ADS)

Typical nanomaterial production processes from daily practice had been performed in order to determine simultaneously the exposure to nanoparticles. They involve mixing of ZnO powder into a liquid, filling and emptying an oven with indium tin oxide (ITO), spraying a suspension of nanoparticles, flame spraying of silanes, and an outside location as comparison.

Möhlmann, Carsten; Welter, Johannes; Klenke, Martin; Sander, Jürgen

2009-05-01

174

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

175

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. PMID:23428798

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

2013-01-01

176

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

177

9 CFR 318.306 - Processing and production records.  

Code of Federal Regulations, 2012 CFR

...306 Processing and production records. At least the following processing and production information shall be...establishment: date of production; product name and...the control of critical factors shall be...

2012-01-01

178

9 CFR 318.306 - Processing and production records.  

Code of Federal Regulations, 2011 CFR

...306 Processing and production records. At least the following processing and production information shall be...establishment: date of production; product name and...the control of critical factors shall be...

2011-01-01

179

9 CFR 381.306 - Processing and production records.  

Code of Federal Regulations, 2013 CFR

...306 Processing and production records. At least the following processing and production information shall be...establishment: Date of production; product name and...the control of critical factors shall be...

2013-01-01

180

9 CFR 381.306 - Processing and production records.  

Code of Federal Regulations, 2011 CFR

...306 Processing and production records. At least the following processing and production information shall be...establishment: Date of production; product name and...the control of critical factors shall be...

2011-01-01

181

9 CFR 381.306 - Processing and production records.  

Code of Federal Regulations, 2012 CFR

...306 Processing and production records. At least the following processing and production information shall be...establishment: Date of production; product name and...the control of critical factors shall be...

2012-01-01

182

9 CFR 318.306 - Processing and production records.  

Code of Federal Regulations, 2013 CFR

...306 Processing and production records. At least the following processing and production information shall be...establishment: date of production; product name and...the control of critical factors shall be...

2013-01-01

183

CITRIC ACID AS A SET RETARDER FOR CALCIUM ALUMINATE PHOSPHATE CEMENTS.  

SciTech Connect

Citric acid added as set retarder significantly contributed to enhancing the setting temperature and to extending the thickening time of a calcium aluminate phosphate (CaP) geothermal cement slurry consisting of calcium aluminate cement (CAC) as the base reactant and sodium polyphosphate (NaP) solution as the acid reactant. The set-retarding activity of citric acid was due to the uptake of Ca{sup 2+} ions from the CAC by carboxylic acid groups within the citric acid. This uptake led to the precipitation of a Ca-complexed carboxylate compound as a set-retarding barrier layer on the CAC grains' surfaces. However, this barrier layer was vulnerable to disintegration by the attack of free Ca{sup 2+} ions from CAC, and also to degradation at elevated temperature, thereby promoting the generation of exothermic energy from acid-base reactions between the CAC and NaP after the barrier was broken. The exothermic reaction energy that was promoted in this way minimized the loss in strength of the citric acid-retarded cement. The phase composition assembled in both retarded and non-retarded cements after autoclaving at 180 C encompassed three reaction products, hydroxyapatite (HOAp), hydrogrossular and boehmite, which are responsible for strengthening the autoclaved cement. The first two reaction products were susceptible to reactions with sulfuric acid and sodium sulfate to form crystalline bassanite scale as the corrosion product. The boehmite phase possessed a great resistance to acid and sulfate. Although the bassanite scales clinging to the cement's surfaces were the major factor governing the loss in weight, they served in protecting the cement from further acid- and sulfate-corrosion until their spallation eventually occurred. Nevertheless, the repetitive processes of HOAp and hydrogrossular {yields} bassanite {yields} spallation played an important role in extending the useful lifetime of CaP cement in a low pH environment at 180 C.

SUGAMA,T.; BROTHERS, L.E.

2005-01-01

184

Magnesium production by plasma-powered processing  

NASA Astrophysics Data System (ADS)

A new process has been developed to extract magnesium from aluminosilicate slags which have high basicity ratios. The process is dependent on the effective utilization of the characteristics of transferred-arc gas plasmas and has important advantages over alternative pyrometallurgical methods of magnesium production. The need for careful control of an invariant slag composition is eliminated, as is the requirement of a vacuum condenser or complex gas quench technology. Significantly improved magnesium yields, when combined with highly efficient usage of the reductant, will greatly enhance the economics of the pyrometallurgical route to magnesium.

Cameron, A. M.; Canham, D. L.; Aurich, V. G.

1990-04-01

185

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

186

Optimal dynamic policies for product and process innovation  

Microsoft Academic Search

Relatively few studies have analytically examined incremental product and process R & D activities after a product is in the marketplace. In this paper, new product demand is modeled as a dynamic function of price and incremental product innovation, while process improvements influence costs. Optimal price, and product and process R & D expenditure patterns are studied analytically and with

Barry L. Bayus

1995-01-01

187

Industrial strategies to help reduce energy consumption: A holistic approach for cement producers  

Microsoft Academic Search

Cement producers have faced a significant rise in energy costs with the introduction of dry-process kilns, with a record average consumption of 100-200 kwh per ton of cement (The Cement Plant Operations Handbook, 2009*). This complex challenge, coupled with rising fuel and energy costs, has prompted cement manufacturers to implement energy management programs to help reduce costs while maintaining competitiveness

D. M. Lorimer; P. Murray

2010-01-01

188

Acrylic bone cement: current concept review.  

PubMed

Acrylic bone cement has had for years an important role in orthopedic surgery. Polymethylmethacrylate (PMMA) has been extended from the ophthalmological and dental fields to orthopedics, as acrylic cement used for fixation of prosthetic implants, for remodeling osteoporotic, neoplastic and vertebral fractures repair. The PMMA bone cement is a good carrier for sustained antibiotic release in the site of infection. Joint prostheses chronic infection requires surgical removal of the implant, in order to eradicate the infection process. This can be performed in the same surgical time (one-stage procedure) or in two separate steps (two-stage procedure, which involves the use of an antibiotic-loaded cement spacer). The mechanical and functional characteristics of the spacers allow a good joint range of motion, weight-bearing in selected cases and a sustained release of antibiotic at the site of infection. The improvement of fixation devices in recent years was not accompanied by the improvement of elderly bone quality. Some studies have tested the use of PMMA bone cement or calcium phosphate as augmentation support of internal fixation of these fractures. Over the past 20 years, experimental study of acrylic biomaterials (bone cement, bioglass ceramic, cement additives, absorbable cement, antibiotic spacers) has been of particular importance, offering numerous models and projects. PMID:23893506

Magnan, B; Bondi, M; Maluta, T; Samaila, E; Schirru, L; Dall'Oca, C

2013-08-01

189

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

190

Cellulase production by the anaerobic digestion process  

SciTech Connect

An anaerobic digestion process is described for the production of cellulolytic enzymes using a methanogenic cellulose-enrichment culture. After a heat treatment designed to destroy all but spore-forming bacteria, this culture produced cellulase from a variety of cellulosic materials as well as from cellobiose. The enzyme system contained endo- and exoglucanase, acted on filter paper, and showed cellobiase and xylanase activities. It was stable at 2/sup 0/C under aerobic conditions and showed a pH optimum at 5 and a temperature optimum at 50/sup 0/C. Endoglucanase and filter paper activities were mostly exogenic, whereas cellobiase and xylanase activities were cell associated. The cellulolytic activity produced by this mixed culture was comparable to that of commercially available fungal preparations, and the process could be useful as an alternate source for these enzymes.

Khan, A.W.; van den Berg, L.

1981-01-01

191

Cementation of colloidal particles on electrodes in a galvanic microreactor.  

PubMed

We have studied the processes leading to the cementation of colloidal particles during their autonomous assembly on corroding copper electrodes within a Cu-Au galvanic microreactor. We determined the onset of particle immobilization through particle tracking, monitored the dissolution of copper as well as the deposition of insoluble products of the corrosion reactions in situ, and showed that particle immobilization initiated after reaction products (RPs) began to deposit on the electrode substrate. We further demonstrated that the time and the extent of RP precipitation and thus the strength of the particle-substrate bond could be tuned by varying the amount of copper in the system and the microreactor pH. The ability to cement colloidal particles at locations undergoing corrosion illustrates that the studied colloidal assembly approach holds potential for applications in dynamic material property adaptation. PMID:23808394

Jan, Linda; Punckt, Christian; Aksay, Ilhan A

2013-07-10

192

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

193

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 Task 1: Assess Ultra-Lightweight Cementing Issues, Task 2: Review Russian Ultra-Lightweight Cement Literature, Task 3: Test Ultra-Lightweight Cements, and Task 8: Develop Field ULHS Cement Blending and Mixing Techniques. Results reported this quarter include: 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; laboratory tests comparing ULHS slurries to foamed slurries and sodium silicate slurries for two different applications; and initial laboratory studies with ULHS in preparation for a field job.

Fred Sabins

2001-07-18

194

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

195

PCC (Portland Cement Concrete) Mix Design.  

National Technical Information Service (NTIS)

Properties of portland cement concrete (PCC) mixes, including workability, strength, durability, and abrasion resistance, are discussed along with the specific mix factors that affect each property. The mix design process is then discussed and the effect ...

D. Janssen

1989-01-01

196

INVESTIGATION OF THE FORMATION OF A PORTLAND CEMENT PLANT DETACHED PLUME  

EPA Science Inventory

A gaseous and particulate source emissions sampling program has been conducted at a Portland Cement production plant in Rapid City South Dakota. The study was conducted to determine the cause of the formation of an opaque detached plume from the plants' dry process kiln. The inst...

197

Mineral of the month: cement  

USGS Publications Warehouse

Hydraulic cement is a virtually ubiquitous construction material that, when mixed with water, serves as the binder in concrete and most mortars. Only about 13 percent of concrete by weight is cement (the rest being water and aggregates), but the cement contributes all of the concrete’s compressional strength. The term “hydraulic” refers to the cement’s ability to set and harden underwater through the hydration of the cement’s components.

van Oss, Hendrik G.

2006-01-01

198

Flavor violating processes with sgoldstino pair production  

NASA Astrophysics Data System (ADS)

In supersymmetric extensions of the standard model of particle physics (SM), goldstino superpartners—scalar and pseudoscalar sgoldstinos—can be light enough for emerging in decays of SM particles. Sgoldstino interaction with SM fields is suppressed by the scale of supersymmetry breaking in the whole theory. Hence, searches for sgoldstinos give an opportunity to probe the underlying mechanism of supersymmetry breaking. Sgoldstino couplings to SM fields are proportional to the supersymmetry breaking parameters—MSSM soft terms—and therefore can lead to flavor violating processes in quark and lepton sectors. We consider flavor violating processes involving sgoldstino pair production which are driven by sgoldstino couplings proportional to squark and slepton soft mass terms, m˜LL2 and m˜RR2. We find that present limits on off-diagonal entries in squark and slepton squared mass matrices allow t-, b-, c-quark and ?-lepton decays at levels available for study with existing data (BaBar, Belle, CLEOc) and in ongoing experiments (LHCb, CMS, ATLAS). In particular, we obtain the following branching ratios Br(t?cSP)?10-7, Br(???SP)?10-7, Br(Bs?SP)?10-4, Br(B?K(*)SP)?10-4, Br(D?SP)?10-7 with sgoldstino subsequent decays into kinematically allowed pairs of SM particles ??, e+e-, ?+?-, etc. Remarkably, the prominent signature of sgoldstino pair production is two muon pairs with pair momenta peaked at sgoldstino masses.

Demidov, S. V.; Gorbunov, D. S.

2012-04-01

199

Pinellas Plant facts. [Products, processes, laboratory facilities  

SciTech Connect

This plant was built in 1956 in response to a need for the manufacture of neutron generators, a principal component in nuclear weapons. The neutron generators consist of a miniaturized linear ion accelerator assembled with the pulsed electrical power supplies required for its operation. The ion accelerator, or neutron tube, requires ultra clean, high vacuum technology: hermetic seals between glass, ceramic, glass-ceramic, and metal materials: plus high voltage generation and measurement technology. The existence of these capabilities at the Pinellas Plant has led directly to the assignment of the lightning arrester connector, specialty capacitor, vacuum switch, and crystal resonator. Active and reserve batteries and the radioisotopically-powered thermoelectric generator draw on the materials measurement and controls technologies which are required to ensure neutron generator life. A product development and production capability in alumina ceramics, cermet (electrical) feedthroughs, and glass ceramics has become a specialty of the plant; the laboratories monitor the materials and processes used by the plant's commercial suppliers of ferroelectric ceramics. In addition to the manufacturing facility, a production development capability is maintained at the Pinellas Plant.

Not Available

1986-09-01

200

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

201

Product Design and Manufacturing Process: Dynamic Implications for Innovation Management  

Microsoft Academic Search

For industrial companies innovations of the product system as well as innovations of the manufacturing processes are essential. Due to technological facts there is a tight relationship between technical products and the processes implemented to generate these products. Innovation management has to take into account the dynamics of the underlying product-process interactions and the resulting constraints coming to a coherent

Joachim Stumpfe

202

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

203

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

204

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

205

Simulation of silica fume blended cement hydration  

Microsoft Academic Search

A model is proposed in this paper to simulate silica fume (SF) blended cement hydration based on the kinetics, stoichiometry\\u000a and physical chemistry of cement hydration and pozzolanic reaction. The pozzolanic reaction degree, volume fraction of hydration\\u000a products, capillary porosity and gel porosity can be obtained from model simulation. By using proper amount of silica fume\\u000a replacement, the microstructure of

J. Yajun; J. H. Cahyadi

2004-01-01

206

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

207

Process improvements during production ramp-up  

E-print Network

Raytheon Company is currently ramping up production radars for a fighter aircraft. This product is doubling production in the next year to meet customer demand; however, the program has not been able to meet the current ...

Chew, Ryan W. (Ryan Wayne)

2007-01-01

208

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

209

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

210

[Effect of vibration for the rheology of some luting cements].  

PubMed

Vibrant load is known to be effective to thin the film thickness of various luting cements. In this study, a vibrator which can change various conditions such as frequency, form of wave were made, and the changes of viscosity, film thickness and bond strength were tested statistically. Furthermore, the most effective condition for the slurry of some luting cements (i.e. domestic two zinc phosphate cements, one polycarboxylate cement and one glass ionomer cement) were investigated. The results obtained were as follows. 1) When vibrant load was applied to the slurry of cement in the setting process, the rise in viscosity was apt to be slower than the same case of static load. 2) The effect of vibration appears in the early sixty seconds especially, and the effect varied with the kind of cement, frequency or form of wave. 3) Vibration was also effective for the increase of compressive strength and of bond strength. PMID:2637503

Kaburagi, K

1989-05-01

211

Process for capturing CO{sub 2} arising from the calcination of the CaCO{sub 3} used in cement manufacture  

SciTech Connect

This paper outlines a new CaCO{sub 3} calcination method for producing a stream of CO{sub 2} (suitable for permanent geological storage after purification and compression). The process is based on the use of very hot CaO particles (T {gt} 1000{sup o}C) to transfer heat from a circulating fluidized bed combustor (CFBC) to a calciner (fluidized with CO{sub 2} and/or steam). Since the fluidized bed combustor and calciner have separate atmospheres, the CO{sub 2} resulting from the decomposition of CaCO{sub 3} can be captured, while the CO{sub 2} generated in the combustion of the fuel in air is emitted to the atmosphere. We demonstrate that with this system it is possible to reduce the CO{sub 2} emissions of a cement plant by around 60%. Furthermore, since the key pieces of equipment are similar to the commercial CFBCs used in power generation plants, it is possible to establish the additional investment required for the system and to estimate the cost per ton of CO{sub 2} avoided for this process to be about 19 $/tCO{sub 2} avoided. 19 refs., 4 figs.

N. Rodriguez; M. Alonso; G. Grasa; J. Carlos Abanades [Instituto Nacional del Carbon, INCAR-CSIC, Oviedo (Spain)

2008-09-15

212

9 CFR 590.680 - Approval of labeling for egg products processed in exempted egg products processing plants.  

Code of Federal Regulations, 2010 CFR

...processed in exempted egg products processing plants. 590.680 Section 590.680 Animals...INSPECTION ACT) Exempted Egg Products Plants § 590.680 Approval of labeling...processed in exempted egg products processing plants. (a) The labels for egg...

2010-01-01

213

9 CFR 590.680 - Approval of labeling for egg products processed in exempted egg products processing plants.  

...processed in exempted egg products processing plants. 590.680 Section 590.680 Animals...INSPECTION ACT) Exempted Egg Products Plants § 590.680 Approval of labeling...processed in exempted egg products processing plants. (a) The labels for egg...

2014-01-01

214

9 CFR 590.680 - Approval of labeling for egg products processed in exempted egg products processing plants.  

Code of Federal Regulations, 2012 CFR

...processed in exempted egg products processing plants. 590.680 Section 590.680 Animals...INSPECTION ACT) Exempted Egg Products Plants § 590.680 Approval of labeling...processed in exempted egg products processing plants. (a) The labels for egg...

2012-01-01

215

9 CFR 590.680 - Approval of labeling for egg products processed in exempted egg products processing plants.  

Code of Federal Regulations, 2011 CFR

...processed in exempted egg products processing plants. 590.680 Section 590.680 Animals...INSPECTION ACT) Exempted Egg Products Plants § 590.680 Approval of labeling...processed in exempted egg products processing plants. (a) The labels for egg...

2011-01-01

216

Experience with roller press systems at Southern Province Cement Company  

Microsoft Academic Search

The upgrade of the circuit #1 cement grinding system at the Southern Province Cement Company Bisha plant has proved to be a successful design of a clinker pre-grinding circuit. The simple layout has fulfilled expectations not only on the basis of production and product quality, but also on installed power and equipment cost, equipment selection, and operating and maintenance costs.

M. N. Sukkar; K. Happ; A. Shahid

2005-01-01

217

Soft X-ray Microscopy of Green Cements  

SciTech Connect

The present status of the cement and concrete industry is not sustainable. The production of Portland cement is responsible for 7% of the CO{sub 2} emissions in the world and existing reinforced concrete infrastructure is deteriorating at a fast pace. The change in the existing technology requires new developments in our understanding of the nanostructure of hydration products and the complex deterioration reactions. We have been developing an elaborate research program to advance the existing cement and concrete science by characterizing its nanostructure by synchrotron radiation. A new generation of green cements is being studied using high-resolution soft x-ray microscopy at the nano-level.

Monteiro, P. J. M.; Mancio, M.; Chae, R.; Ha, J. [Department of Civil and Environmental Engineering, University of California, Berkeley, CA 94720 (United States); Kirchheim, A. P. [Department of Civil Engineering, Federal University of Rio Grande do Sul, Porto Alegre, RS, 90035-190 (Brazil); Fischer, P. [Center for X-ray Optics, Lawrence Berkeley National Laboratory, Berkeley CA, 94720 (United States); Tyliszczak, T. [Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley CA, 94720 (United States)

2011-09-09

218

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

219

Alignment strategies for drug product process development and manufacturing  

E-print Network

The transfer of information between the drug product development and manufacturing organizations is fundamental to drug product commercialization. This information is used to characterize the product-process interaction ...

Garvin, Christopher John

2012-01-01

220

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

221

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

222

Atmospheric Processing Module for Mars Propellant Production  

NASA Technical Reports Server (NTRS)

The multi-NASA center Mars Atmosphere and Regolith COllectorPrOcessor for Lander Operations (MARCO POLO) project was established to build and demonstrate a methaneoxygen 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 CO(sub 2) 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 H(sub 2)CO(sub 2) 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 CO(sub 2) hr for 14 hr, (3) the testing of the CO(sub 2) freezer subsystem, and (4) the integration and testing of the two subsystems to verify the desired production rate of 31.7 g CH(sub 4) hr and 71.3 g H(sub 2)O hr along with verification of their purity. The resulting 2.22 kg of CH(sub 2)O(sub 2) propellant per 14 hr day (including O(sub 2) from electrolysis of water recovered from regolith, which also supplies the H(sub 2) for methanation) is of the scale needed for a Mars Sample Return mission. In addition, the significance of the project to NASAs new Mars exploration plans will be discussed.

Muscatello, Anthony C.

2014-01-01

223

Methodology Modelling: Combining Software Processes with Software Products \\Lambda  

E-print Network

Methodology Modelling: Combining Software Processes with Software Products \\Lambda Jun Han and Jim Processes with Software Products Jun Han and Jim Welsh Software Verification Research Centre Department­mails: fhan,jimg@cs.uq.oz.au Abstract Software processes and software products are the two inseparable issues

Han, Jun

224

Hydration reactions of cement combinations containing vitrified incinerator fly ash  

SciTech Connect

One treatment option for municipal solid waste incinerator fly ash (IFA) is vitrification. The process yields a material containing reduced levels of trace metals relative to the original ash. The material is glassy and potentially suitable as a cement component in concrete. This paper examines the vitrification of an IFA and studies the hydration reactions of combinations of this vitrified material and Portland cement (PC). Isothermal conduction calorimetry, powder X-ray diffraction (XRD), thermogravimetry (TG) and scanning electron microscopy were employed to study the hydration reactions. As the levels of vitrified ash increase, the quantities of AFt phase produced decrease, whilst quantities of AFm phase increase, due to the reduced levels of sulfate in the vitrified ash. The levels of calcium silicate hydrate (CSH) gel (inferred from estimates of quantities of gel-bound water) remain constant at 28 days regardless of vitrified ash content, indicating that the material is contributing toward the formation of this product.

Dyer, Thomas D.; Dhir, Ravindra K

2004-05-01

225

Nano-ChemoMechanical assessment of Rice Husk Ash cement by wavelength dispersive spectroscopy and nanoindentation  

E-print Network

Cement global production stands at 3 Giga tons making concrete the most consumed structural mateial worldwide. This massively produced material comes with a heavy environmental footprint rendering the cement industry ...

Abuhaikal, Muhannad (Muhannad A. R.)

2011-01-01

226

Process management applications in biopharmaceutical drug production  

E-print Network

Genzyme's manufacturing and supply chain organization is responsible for the production and delivery of medically necessary medicines for patients with rare diseases around the world. Because of the nature of the products ...

Smith, Stephen E

2011-01-01

227

Corrosion resistant cemented carbide  

Microsoft Academic Search

This paper describes a corrosion resistant cemented carbide composite. It comprises: a granular tungsten carbide phase, a semi-continuous solid solution carbide phase extending closely adjacent at least a portion of the grains of tungsten carbide for enhancing corrosion resistance, and a substantially continuous metal binder phase. The cemented carbide composite consisting essentially of an effective amount of an anti-corrosion additive,

Hong

1990-01-01

228

Making periclase cement waterproof  

Microsoft Academic Search

Conclusions Waterproofing of pure periclase cement with 1.5% petroleum resin is due to its lower capillary and sorption water absorption; the treatment also prevents caking. The activity of periclase cement that has been waterproofed with petroleum resin remains practically unaltered during storage.

L. B. Khoroshavin; T. A. Drozdova; P. N. D'yachov

1967-01-01

229

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

230

PRODUCTION OF CARBON PRODUCTS USING A COAL EXTRACTION PROCESS  

Microsoft Academic Search

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

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

2004-01-01

231

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

232

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

233

A software product line process simulator  

Microsoft Academic Search

A software product line is a set of software- intensive systems sharing a common, managed set of features that satisfy the specific needs of a particular market segment or mission, and are developed from a common set of core assets in a prescribed way. A software product line approach promises shorter time-to-market and decreased life cycle cost. However, those benefits

Yu Chen; Gerald C. Gannod; James S. Collofello

2006-01-01

234

BD monomer and elastomer production processes  

Microsoft Academic Search

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

Jeremiah Lynch

2001-01-01

235

MCFC integrated system in a biodiesel production process  

Microsoft Academic Search

The continuous increasing in biodiesel production by transesterification process is leading to an excess of glycerol production as a byproduct.The utilization of this huge amount of glycerol appears as a not easy solvable problem and thus several authors have proposed alternative ways.The integration of the main production process with a glycerol feed molten carbonate fuel cells bottoming cycle, to satisfy

F. Urbani; S. Freni; A. Galvagno; V. Chiodo

2011-01-01

236

Extracting Silicon From Sodium-Process Products  

NASA Technical Reports Server (NTRS)

New acid leaching process purifies silicon produced in reaction between silicon fluoride and sodium. Concentration of sodium fluoride and other impurities and byproducts remaining in silicon are within acceptable ranges for semi-conductor devices. Leaching process makes sodium reduction process more attractive for making large quantities of silicon for solar cells.

Kapur, V.; Sanjurjo, A.; Sancier, K. M.; Nanis, L.

1982-01-01

237

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.

238

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

239

Powder-Metallurgy Process And Product  

NASA Technical Reports Server (NTRS)

Rapid-solidification processing yields alloys with improved properties. Study undertaken to extend favorable property combinations of I/M 2XXX alloys through recently developed technique of rapid-solidification processing using powder metallurgy(P/M). Rapid-solidification processing involves impingement of molten metal stream onto rapidly-spinning chill block or through gas medium using gas atomization technique.

Paris, Henry G.

1988-01-01

240

Performance of Concrete Made With Slag Cement and  

E-print Network

! Individually ! Together ! Conclusions #12;! Non-metallic product of an iron blast furnace ! Granulated What is slag cement? #12;! Non-metallic product of an iron blast furnace ! Granulated ! Ground ! Cementitious

241

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. PMID:18253965

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

2008-01-01

242

The density of cement phases  

SciTech Connect

The densities of principal crystalline phases occurring in Portland cement are critically assessed and tabulated, in some cases with addition of new data. A reliable and self-consistent density set for crystalline phases was obtained by calculating densities from crystallographic data and unit cell contents. Independent laboratory work was undertaken to synthesize major AFm and AFt cement phases, determine their unit cell parameters and compare the results with those recorded in the literature. Parameters were refined from powder diffraction patterns using CELREF 2 software. A density value is presented for each phase, showing literature sources, in some cases describing limitations on the data, and the weighting attached to numerical values where an averaging process was used for accepted data. A brief discussion is made of the consequences of the packing of water to density changes in AFm and AFt structures.

Balonis, M. [Department of Chemistry, Meston Building, University of Aberdeen, Aberdeen, AB24 3UE, Scotland (United Kingdom)], E-mail: m.balonis@abdn.ac.uk; Glasser, F.P. [Department of Chemistry, Meston Building, University of Aberdeen, Aberdeen, AB24 3UE, Scotland (United Kingdom)

2009-09-15

243

Probabilistic analysis of the influence of the bonding degree of the stem–cement interface in the performance of cemented hip prostheses  

Microsoft Academic Search

The long-term behavior of the stem–cement interface is one of the most frequent topics of discussion in the design of cemented total hip replacements, especially with regards to the process of damage accumulation in the cement layer. This effect is analyzed here comparing two different situations of the interface: completely bonded and debonded with friction. This comparative analysis is performed

M. A. Pérez; J. Grasa; J. M. García-Aznar; J. A. Bea; M. Doblaré

2006-01-01

244

Freshwater (phytoherm) reefs: the role of biofilms and their bearing on marine reef cementation  

NASA Astrophysics Data System (ADS)

Bioconstructions in carbonate-rich freshwater environments generally lead to the development of thick autochthonous tufa deposits. In rivers systems, these large plant-dominated freshwater reef frameworks (phytoherms) are capable of damming the water courses to produce chains of lakes. The resulting phytoherms profoundly modify both local environment and sedimentation patterns in their vicinity and provide a wide range of niches for biota. Subaqueous fringe cements coat all exposed surfaces. They bind the ephemeral plant frameworks, providing a cement framework and give rigidity to the bioconstructions. Peloids are intimately associated with the development of these cements and frequently infil intra-reef and framework cavities. Evidence is presented to suggest that both micritic fringe cements and peloids are the product of biological mediation associated with a procaryote—microphyte biofilm and the presence of organic detritus. The bladed low-magnesium calcite fringes which develop subsequently on the micrite fringes and peloids are possibly slower formed inorganic precipitates. The close morphological similarities between phytoherm fringe cements and peloids, and their marine reef counterparts are considered to be more than coincidental. It is argued that procaryote—microphyte biofilms are also responsible for micritic precipitates in the shallow photic marine realm with bacterial films possibly carrying the process deep into unlit reef cavities and conduits, and deep water lithoherms.

Pedley, Martyn

1992-08-01

245

Cement penetration after patella venting  

Microsoft Academic Search

There is a high rate of patellofemoral complications following total knee arthroplasty. Optimization of the cement–bone interface by venting and suction of the tibial plateau has been shown to improve cement penetration. Our study was designed to investigate if venting the patella prior to cementing improved cement penetration.Ten paired cadaver patellae were allocated prior to resurfacing to be vented or

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

2009-01-01

246

Work Structuring to Achieve Integrated ProductProcess Design  

E-print Network

Work Structuring to Achieve Integrated Product­Process Design Cynthia C. Y. Tsao, A.M.ASCE1 ; Iris presents "work structuring," a term used to describe the effort of integrating product and process design throughout the project development process. To illustrate current work structuring practice, we describe

Tommelein, Iris D.

247

Treatment of waste water from marine products processing plants  

Microsoft Academic Search

Different types of pollutants produced as by?products in various marine product processing plants are described. A detailed discussion on the effects of these polluting materials on the environment follows. Various technologies available for treating waste water contaminated with the above are introduced. Methods are described for evaluating various processing methods and choosing a method that meets individual processing requirements based

Kazuo Sano

1988-01-01

248

Kinetics and deposit morphology of gold cemented on magnesium, aluminum, zinc, iron and copper from ammonium thiosulfate–ammonia solutions  

Microsoft Academic Search

The kinetics of gold cementation by magnesium aluminum, zinc, iron and copper at equal conditions as well as the morphology of cementation products and the dissolution of cementing agents were investigated. Both the effect of cementing agents on gold cementation rate and the dissolution of metals decrease in order Cu>Zn>Mg>Fe>Al. High dissolution of magnesium, zinc, iron and copper per mol

M. Karavasteva

2010-01-01

249

Effect of temporary cements on the microtensile bond strength of self-etching and self-adhesive resin cement.  

PubMed

Abstract Objective. The aim of this study was to evaluate the microtensile bond strength (µTBS) of self-etching and self-adhesive resin cement systems to dentin affected by the presence of remnants of either eugenol-containing or eugenol-free temporary cements. Materials and methods. Thirty extracted teeth were obtained and a flat dentin surface was exposed on each tooth. Acrylic blocks were fabricated and cemented either with one of two temporary cements, one zinc oxide eugenol (ZOE) and one eugenol free (ZOE-free), or without cement (control). After cementation, specimens were stored in water at 37°C for 1 week. The restorations and remnants of temporary cements were removed and dentin surfaces were cleaned with pumice. Resin composite blocks were cemented to the bonded dentin surfaces with one of two resin cements, either self-etching (Panavia F 2.0) or self-adhesive (RelyX U-100). After 24 h, the specimens were sectioned to obtain beams for submission to µTBS. The fracture mode was evaluated under a stereoscopic loupe and a scanning electron microscope (SEM). Data from µTBS were submitted to two-way repeated-measure ANOVA and the Tukey test (alpha = 0.05). Results. The cross-product interaction was statistically significant (p < 0.0003). The presence of temporary cements reduced the bond strength to Panavia self-etching resin cements only (p < 0.05). Fracture occurred predominantly at the dentin-adhesive interface. Conclusions. The presence of eugenol-containing temporary cements did not interfere in the bond strength to dentin of self-adhesive resin cements. PMID:24837710

Carvalho, Edilausson Moreno; Carvalho, Ceci Nunes; Loguercio, Alessandro Dourado; Lima, Darlon Martins; Bauer, José

2014-11-01

250

Effect of stem preheating and precooling on residual stress formation at stem/cement interface for cemented hip implants.  

PubMed

PMMA polymerization is an exothermic phenomenon during which stresses and porosity are observed. An experimental model is devised to directly measure radial forces, to be converted to radial stresses, at the stem/cement interface, and temperatures at both interfaces during cement curing. The effects of stem and bone cement initial temperatures (preheating or precooling vs. room temperature) as well as mixing method (hand vs. vacuum mixing) and cement type (Simplex P vs. Palacos R) on radial stress and temperatures are investigated. Compressive radial residual stresses at the stem/cement interface are measured for hand mixed PMMA with preheated stem, with a maximum magnitude of 1.0 MPa. No radial residual stresses are observed when the stem is initially at room temperature or precooled, suggesting that during curing, bone cement can polymerize away from the stem/cement interface generating radial stress in tension or gaps. The results demonstrate the reverse direction of polymerization for preheated stems. Stem preheating significantly increases transient temperatures at the bone/cement interface and also the risk of bone thermal necrosis, because the exposure time to high temperature is prolonged. The results provide interfacial characteristics for accurate modeling of bone cement polymerization to better understand the debonding process of cemented hip prostheses. PMID:20091924

Madrala, A; Nuño, N

2010-04-01

251

Product and Process Comparisons (Engineering Statistics Handbook)  

NSDL National Science Digital Library

This chapter of the NIST Engineering Statistics handbook presents the background and specific analysis techniques needed to compare the performance of one or more processes against known standards or one another.ÃÂÃÂ It contains an introduction and information about comparisons with one process, two processes, and three or more processes or samples. Topics include outliers, trends, confidence intervals for means and proportions for one sample. Also included are materials on ANOVA, Kruskal Wallis tests, tests for equivalence of variances, variance components, chi-square tests for contingency tables and multiple comparisons.

Filliben, James; Heckert, Alan

2009-02-12

252

Cement for passive damping  

NASA Astrophysics Data System (ADS)

Multifunctional concretes capable of both structural and non- structural functions are made possible by appropriate admixtures. The use of acid treated silica fume (15% by weight of cement), latex (20 - 30% by weight of cement) or methylcellulose (0.4 - 0.8% by weight of cement) as an admixture gave the vibration damping function (with loss tangent up to 0.18, i.e., up to 390% increase, and loss modulus up to 2.2 GPa, i.e., up to 2200% increase, at 0.2 - 2 Hz loading).

Fu, Xuli; Li, Xiaohui; Chung, Deborah D. L.

1998-06-01

253

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.

254

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

255

Novel cement matrices by accelerated hydration of the ferrite phase in portland cement via chemical activation: kinetics and cementitious properties  

Microsoft Academic Search

The effects of the admixture of potassium citrate and potassium carbonate to portland cement with and without gypsum on the kinetics of the dissolution of the clinker phases, formation of hydration products, and cementitous properties in ISO-mortar and concrete were investigated. Quantitative X-ray diffraction (QXRD) data indicate that the admixture of citrate to portland cements increases the dissolution rate of

Wolfgang Schwarz

1995-01-01

256

Pharmaceutical tablet compaction : product and process design  

E-print Network

This thesis explores how tablet performance is affected by microstructure, and how microstructure can be controlled by selection of excipients and compaction parameters. A systematic strategy for formulation and process ...

Pore, Mridula

2009-01-01

257

A process for improving long-term production planning  

E-print Network

This project presents improvements to the business process used to generate the Sikorsky five-year production scheduling plan that is a central coordinating process for company operations. Recommendations will improve the ...

McIntosh, Timothy, Jr. (Timothy P.)

2011-01-01

258

Mitigating the impact of a time-dependent production process  

E-print Network

Value-added processes that bear associated wait times occur frequently during production manufacturing and increase cycle time. Since the wait time is integral to the value created by the process, it can be difficult to ...

Dudnik, Sara A

2007-01-01

259

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...

260

Production Goals Process: Means and End  

ERIC Educational Resources Information Center

To remain educationally accountable, agriculture instructors must use production enterprises whenever they are available, exploiting their potential for facilitating the development of students' decision-making abilities through management practices, presented here in sequential development (student-set goals, standards, records, record analyses,…

Leske, Gary W.

1974-01-01

261

The effect of processed fly ashes on the durability and the corrosion of steel rebars embedded in cement–modified fly ash mortars  

Microsoft Academic Search

This paper deals with the study of corrosion level of reinforcing steel bars embedded in Portland cement mortars containing different types of fly ash. Fly ashes used were obtained by physico-chemical treatments of an original F class fly ash to modify their magnetic properties and reduce their particle size. An original fly ash (T0) and three types of modified ashes

P. Garcés; L. G. Andión; E. Zornoza; M. Bonilla; J. Payá

2010-01-01

262

Reduced product yield in chemical processes by second law effects  

NASA Technical Reports Server (NTRS)

An analysis of second law effects in chemical processes, where product yield is explicitly related to the individual irreversibilities within the process to indicate a maximum theoretical yield, is presented. Examples are given that indicate differences between first and second law approaches toward process efficiency and process yield. This analysis also expresses production capacity in terms of the heating value of a product. As a result, it is particularly convenient in analyzing fuel conversion plants and their potential for improvement. Relationships are also given for the effects of irreversibilities on requirements for process heat and for feedstocks.

England, C.; Funk, J. E.

1980-01-01

263

[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

264

Thermal processing of hydroxyapatite for coating production.  

PubMed

Thermally processed hydroxyapatite coatings used on dental implants and hip prostheses for enhanced fixation may typically consist of a number of chemical and structural phases. These phases affect coating performance and tissue attachment. Hydroxyapatite was plasma sprayed to examine the phase evolution during processing. Coatings were examined with X-ray diffraction and elemental analysis. Results indicate that phase transformations are produced by (a) preferential removal of hydroxyl and phosphate leading to a change in melt composition, and (b) the high cooling rate due to the thermal spray process. Hydroxyl group removal promotes the amorphous phase and oxyapatite. Further heating produces a less viscous melt facilitating decomposition of hydroxyapatite to tricalcium and tetracalcium phosphate. Phosphate removal during flight produces a more calcium-rich melt preferring tetracalcium phosphate and calcium oxide formation. A proposed model shows the phase location within the lamellae of these coatings. Coating processes must thus prevent removal of hydroxide and phosphate during processing to maximize the hydroxyapatite content. PMID:9492219

Gross, K A; Berndt, C C

1998-03-15

265

The product innovation process and GDP dynamics  

Microsoft Academic Search

In this paper, we explain GDP dynamics through an analysis of the forces that modify the structure of the economy. These forces\\u000a are represented by the entry of new firms and product innovations. Our model is inspired by Bak’s sand pile model, and the\\u000a entry of a new firm or innovation is comparable to dropping a grain of sand in

Gianfranco Giulioni

2011-01-01

266

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

267

Process and apparatus for ethylene production  

Microsoft Academic Search

A thermal cracking process and apparatus are disclosed for economical manufacture of lower olefins and valuable coproducts by pyrolysis of liquid or gaseous hydrocarbon feedstocks ranging from ethane to tar sands particularly feedstocks, such as gas oil, naphtha, residual oils or tar sands. The pyrolysis unit is a riser reactor heated by hot agglomerated ash particles and designed for short

Pavilon

1979-01-01

268

Partial oxidation process with production of power  

Microsoft Academic Search

Power is developed by an expansion turbine in which the working fluid is a gaseous mixture comprising all of the hot raw gas stream leaving an unpacked partial oxidation gas generator, after removing, if present, a portion of the entrained solids, in admixture with a temperature moderating stream. A molal increase is associated with the partial oxidation process. Power is

E. M. Barber; J. R. Muenger; D. L. Alexander; W. G. Schlinger

1978-01-01

269

Separation processes during binary monotectic alloy production  

NASA Technical Reports Server (NTRS)

Observation of microgravity solidification processes indicates that outside of sedimentation, at least two other important effects can separate the phases: critical-point wetting and spreading; and thermal migration of second-phase droplets due to interfacial tension gradients. It is difficult to study these surface tension effects while in a unit gravity field. In order to investigate the processes occurring over a temperature range, i.e., between a consolute point and the monotectic temperature, it is necessary to use a low-gravity environment. The MSFC drop tube (and tower), the ballistic trajectory KC-135 airplane, and the Space Shuttle are ideal facilities to aid formation and testing of hypotheses. Much of the early work in this area focuses on transparent materials so that process dynamics may be studied by optical techniques such as photography for viewing macro-processes; holography for studying diffusional growth; spinodal decomposition and coalescence; ellipsometry for surface wetting and spreading effects; and interferometry and spectroscopy for small-scale spatial resolution of concentration profiles.

Frazier, D. O.; Facemire, B. R.; Kaukler, W. F.; Witherow, W. K.; Fanning, U.

1984-01-01

270

Neutron scattering studies of hydrating cement pastes  

NASA Astrophysics Data System (ADS)

The progress of the hydration reactions of tricalcium silicate (C3S) has been followed using quasielastic neutron scattering (QNS) at an energy resolution of 60 ?eV and a momentum transfer of q=1 Å-1. The degree of reaction in the hydrating cement paste is inferred from the fraction of water that is chemically bound to the cement reaction products and the known stoichiometry of C3S hydration. Three different water-to-cement ratios were studied in this experiment: W/C=0.7, 0.5 and 0.3. The results of an Avrami-model analysis of the first 15 h of the reaction are consistent with three types of C3S-H2O reaction product morphology and growth mechanisms: (i) a plate-type product phase from either phase boundary growth with no nucleation; (ii) diffusion-limited growth with constant nucleation; or (iii) a needle-type product phase with phase boundary growth and constant nucleation. Analysis of the later-time diffusion-limited portion of the reaction provides apparent diffusion constants for the migration of water through the C3S hydration products. These data indicate that the diffusion constants vary approximately exponentially over the range of water-to-cement values studied.

Berliner, R.; Popovici, M.; Herwig, K.; Jennings, H. M.; Thomas, J.

1998-04-01

271

Solar utility and renewability evaluation for biodiesel production process  

Microsoft Academic Search

A new design concept using solar utility to supply steam and electricity for biodiesel production was proposed. A new indicator, called the renewability index, was then defined and quantified by exergy to evaluate the benefits of substituting fossil fuel utility facilities with solar utility facilities. To reduce the unfavorable environmental impacts of the biodiesel production process, a novel process on

Zhi Hou; Danxing Zheng

2009-01-01

272

"Key Moments" as Pedagogical Windows into the Video Production Process  

ERIC Educational Resources Information Center

In this article, we trace learning across the digital video production process through case studies with four youth media arts organizations (YMAOs) across the United States. We hypothesize that what these organizations share is a series of key moments throughout the production process in which youth must articulate the relationship between the…

Halverson, Erica; Gibbons, Damiana

2010-01-01

273

Constrained Nonlinear Predictive Control for Maximizing Production in Polymerization Processes  

Microsoft Academic Search

In this brief, a new constrained nonlinear predictive control scheme is proposed for maximizing the production in polymerization processes. The key features of the proposed feedback strategy are its ability to rigorously handle the process constraints (input saturation, maximum allowed heat production, maximal temperature values, and rate of change) as well as its real time implementability due to the low

Mazen Alamir; Nida Sheibat-Othman; Sami Othman

2007-01-01

274

Product-Process Distinctions in ELT Curriculum Theory and Practice  

ERIC Educational Resources Information Center

ELT theory classifies curricula as belonging to one of two contrasting approaches: either process or product. While foundation-level teacher education literature offers strongly product-oriented advice, research- and theory-oriented texts stress the need to negotiate with learners, and to take language-learning processes into account. This article…

Wette, Rosemary

2011-01-01

275

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

276

GLOBAL OPTIMIZATION OF ENERGY AND PRODUCTION IN PROCESS INDUSTRIES: A  

E-print Network

GLOBAL OPTIMIZATION OF ENERGY AND PRODUCTION IN PROCESS INDUSTRIES: A GENETIC ALGORITHM APPLICATION in a particular mill in the kraft pulp and paper industry, in order to optimize energy the costs and production a genetic algorithm is developed and applied for the optimal assignment of all the production sections

Neumaier, Arnold

277

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

278

Cyclic Thermodynamic Processes and Entropy Production  

Microsoft Academic Search

We study the time evolution of a periodically driven quantum-mechanical system coupled to several reservoirs of free fermions\\u000a at different temperatures. This is a paradigm of a cyclic thermodynamic process. We introduce the notion of a Floquet Liouvillean\\u000a as the generator of the dynamics of the coupled system on an extended Hilbert space. We show that the time-periodic state\\u000a which

Walid K. Abou Salem; Jürg Fröhlich

2007-01-01

279

Product review: lucis image processing software.  

PubMed

Lucis is a software program that allows the manipulation of images through the process of selective contrast pattern emphasis. Using an image-processing algorithm called Differential Hysteresis Processing (DHP), Lucis extracts and highlights patterns based on variations in image intensity (luminance). The result is that details can be seen that would otherwise be hidden in deep shadow or excessive brightness. The software is contained on a single floppy disk, is easy to install on a PC, simple to use, and runs on Windows 95, Windows 98, and Windows NT operating systems. The cost is $8,500 for a license, but is estimated to save a great deal of money in photographic materials, time, and labor that would have otherwise been spent in the darkroom. Superb images are easily obtained from unstained (no lead or uranium) sections, and stored image files sent to laser printers are of publication quality. The software can be used not only for all types of microscopy, including color fluorescence light microscopy, biological and materials science electron microscopy (TEM and SEM), but will be beneficial in medicine, such as X-ray films (pending approval by the FDA), and in the arts. PMID:10206154

Johnson, J E

1999-04-01

280

Product Binding Varies Dramatically between Processive and Nonprocessive Cellulase Enzymes*  

PubMed Central

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.; Stahlberg, Jerry; Himmel, Michael E.; Crowley, Michael F.; Beckham, Gregg T.

2012-01-01

281

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

282

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

283

Impact of hydroxypropylguars on the early age hydration1 of portland cement2  

E-print Network

Impact of hydroxypropylguars on the early age hydration1 of portland cement2 3 4 Thomas Poinot­19]. It appears that sugars could be adsorbed to cement phases by a49 chelation process. It can thereby form to Taplin53 hal-00758284,version2-15Feb2013 #12;4 [13], sugars could bind to the cement phases if they have

Boyer, Edmond

284

Impact of hydroxypropylguars on the early age hydration1 of portland cement2  

E-print Network

Impact of hydroxypropylguars on the early age hydration1 of portland cement2 3 4 Thomas Poinot could be adsorbed to cement phases by a48 chelation process. It can thereby form a temporary barrier [13], sugars could bind to the cement phases if they have a HO-C=O group, or it could be53 formed

285

From Rocks to Cement. What We Make. Science and Technology Education in Philippine Society.  

ERIC Educational Resources Information Center

This module deals with the materials used in making concrete hollow blocks. Topics discussed include: (1) igneous, metamorphic, and sedimentary rocks; (2) weathering (the process of breaking down rocks) and its effects on rocks; (3) cement; (4) stages in the manufacturing of Portland cement; and (5) the transformation of cement into concrete…

Philippines Univ., Quezon City. Science Education Center.

286

A model for porosity reduction in quartzite reservoirs by quartz cementation  

Microsoft Academic Search

Quartz cementation is an important process of porosity reduction in sandstones. A mathematical model is presented for predicting the distribution and amount of quartz cement in a sandstone reservoir as a function of time and space. The approach combines kinetics and transport mechanism and incorporates the following assumptions: (1) no compaction during cementation, (2) transport of dissolved silica by advection,

Martin Canals; Jean Dominique Meunier

1995-01-01

287

Renewable hydrogen production for fossil fuel processing  

SciTech Connect

In the fundamental biological process of photosynthesis, atmospheric carbon dioxide is reduced to carbohydrate using water as the source of electrons with simultaneous evolution of molecular oxygen: H{sub 2}O + CO{sub 2} + light {yields} O{sub 2} + (CH{sub 2}O). It is well established that two light reactions, Photosystems I and II (PSI and PSII) working in series, are required to perform oxygenic photosynthesis. Experimental data supporting the two-light reaction model are based on the quantum requirement for complete photosynthesis, spectroscopy, and direct biochemical analysis. Some algae also have the capability to evolve molecular hydrogen in a reaction energized by the light reactions of photosynthesis. This process, now known as biophotolysis, can use water as the electron donor and lead to simultaneous evolution of molecular hydrogen and oxygen. In green algae, hydrogen evolution requires prior incubation under anaerobic conditions. Atmospheric oxygen inhibits hydrogen evolution and also represses the synthesis of hydrogenase enzyme. CO{sub 2} fixation competes with proton reduction for electrons relased from the photosystems. Interest in biophotolysis arises from both the questions that it raises concerning photosynthesis and its potential practical application as a process for converting solar energy to a non-carbon-based fuel. Prior data supported the requirement for both Photosystem I and Photosystem II in spanning the energy gap necessary for biophotolysis of water to oxygen and hydrogen. In this paper we report the at PSII alone is capable of driving sustained simultaneous photoevolution of molecular hydrogen and oxygen in an anaerobically adapted PSI-deficient strain of Chlamydomonas reinhardtii, mutant B4, and that CO{sub 2} competes as an electron acceptor.

Greenbaum, E.; Lee, J.W.; Tevault, C.V. [and others

1995-06-01

288

Biohydrogen gas production from food processing and domestic wastewaters  

Microsoft Academic Search

The food processing industry produces highly concentrated, carbohydrate-rich wastewaters, but their potential for biological hydrogen production has not been extensively studied. Wastewaters were obtained from four different food-processing industries that had chemical oxygen demands of 9g\\/L (apple processing), 21g\\/L (potato processing), and 0.6 and 20g\\/L (confectioners A and B). Biogas produced from all four food processing wastewaters consistently contained 60%

Steven W. Van Ginkel; Sang-Eun Oh; Bruce E. Logan

2005-01-01

289

The Kosmosdale expansion project [cement plant upgrade  

Microsoft Academic Search

Kosmos Cement Company, a partnership between Southdown (now CEMEX, responsible for operation) and Lonestar Industries (now Heidelberger) decided in 1998 to increase the clinker production of the Kosmosdale plant from 2500 stpd to 4700 stpd. To achieve this capacity increase of almost 90%, extensive additions and modifications had to be made in almost all manufacturing areas. These main areas were

A. Rowley; D. Babel

2002-01-01

290

Optimisation of a two-liquid component pre-filled acrylic bone cement system: a design of experiments approach to optimise cement final properties.  

PubMed

The initial composition of acrylic bone cement along with the mixing and delivery technique used can influence its final properties and therefore its clinical success in vivo. The polymerisation of acrylic bone cement is complex with a number of processes happening simultaneously. Acrylic bone cement mixing and delivery systems have undergone several design changes in their advancement, although the cement constituents themselves have remained unchanged since they were first used. This study was conducted to determine the factors that had the greatest effect on the final properties of acrylic bone cement using a pre-filled bone cement mixing and delivery system. A design of experiments (DoE) approach was used to determine the impact of the factors associated with this mixing and delivery method on the final properties of the cement produced. The DoE illustrated that all factors present within this study had a significant impact on the final properties of the cement. An optimum cement composition was hypothesised and tested. This optimum recipe produced cement with final mechanical and thermal properties within the clinical guidelines and stated by ISO 5833 (International Standard Organisation (ISO), International standard 5833: implants for surgery-acrylic resin cements, 2002), however the low setting times observed would not be clinically viable and could result in complications during the surgical technique. As a result further development would be required to improve the setting time of the cement in order for it to be deemed suitable for use in total joint replacement surgery. PMID:25005558

Clements, James; Walker, Gavin; Pentlavalli, Sreekanth; Dunne, Nicholas

2014-10-01

291

9 CFR 590.680 - Approval of labeling for egg products processed in exempted egg products processing plants.  

Code of Federal Regulations, 2013 CFR

...ACT) Exempted Egg Products Plants § 590.680 Approval of...exempted egg products processing plants. (a) The labels for egg products which are capable for use as human food shall be submitted...be the same as for official plants as required in §...

2013-01-01

292

Entropy production in oscillatory processes during photosynthesis.  

PubMed

The flow of matter and heat and the rate of enzymatic reactions are examined using two models of photosynthesis that exhibit sustained and damped oscillatory dynamics, with the objective of calculating the rate of entropy generation and studying the effects of temperature and kinetic constants on the thermodynamic efficiency of photosynthesis. The global coefficient of heat transfer and the direct and inverse constants of the formation reaction of the RuBisCO-CO2 complex were used as control parameters. Results show that when the system moves from isothermal to non-isothermal conditions, the transition from a steady state to oscillations facilitates an increase in the energy efficiency of the process. The simulations were carried out for two photosynthetic models in a system on a chloroplast reactor scale. PMID:24162177

López-Agudelo, Víctor A; Barragán, Daniel

2014-01-01

293

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); Najjar, Mitri S. (Wappingers Falls, NY)

1993-01-01

294

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

295

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

296

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

297

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

298

Issues of CBD Product Quality and Process Quality  

Microsoft Academic Search

This position paper presents arguments for including the properties of processes involved in various approaches to component-based software development in predicting sys- tem properties. It discusses how processes impact on sy s- tem properties and relates the issues raised to standards that already address process and product quality. Although many standards still apply, CBD changes interpretations and emphases.

Mark Woodman; Oddur Benediktsson; Bruno Lefever; Friedrich Stallinger

299

Fracture model for cemented aggregates  

A mechanisms-based fracture model applicable to a broad class of cemented aggregates and, among them, plastic-bonded explosive (PBX) composites, is presented. The model is calibrated for PBX 9502 using the available experimental data under uniaxial compression and tension gathered at various strain rates and temperatures. We show that the model correctly captures inelastic stress-strain responses prior to the load peak and it predicts the post-critical macro-fracture processes, which result from the growth and coalescence of micro-cracks. In our approach, the fracture zone is embedded into elastic matrix and effectively weakens the material's strength along the plane of the dominant fracture.

Zubelewicz, Aleksander; Thompson, Darla G.; Ostoja-Starzewski, Martin; Ionita, Axinte; Shunk, Devin; Lewis, Matthew W.; Lawson, Joe C.; Kale, Sohan; Koric, Seid

2013-01-01

300

Microstructure-controllable Laser Additive Manufacturing Process for Metal Products  

NASA Astrophysics Data System (ADS)

Controlling the cooling rate of alloy during solidification is the most commonly used method for varying the material microstructure. However, the cooling rate of selective laser melting (SLM) production is constrained by the optimal parameter settings for a dense product. This study proposes a method for forming metal products via the SLM process with electromagnetic vibrations. The electromagnetic vibrations change the solidification process for a given set of SLM parameters, allowing the microstructure to be varied via magnetic flux density. This proposed method can be used for creating microstructure-controllable bio-implant products with complex shapes.

Huang, Wei-Chin; Chuang, Chuan-Sheng; Lin, Ching-Chih; Wu, Chih-Hsien; Lin, De-Yau; Liu, Sung-Ho; Tseng, Wen-Peng; Horng, Ji-Bin

301

Recycled rubber in cement composites  

SciTech Connect

Disposal of 200 million waste tires in the US each year has become a major problem. An environmentally sound innovative technology of recycling rubber in cement matrix was examined. Using silane coupling agent the rubber was bonded to the hydrating cement making a lighter composite, which absorbed more energy than ordinary Portland cement. The bonding information was obtained by peel strength analysis. SEM was used to understand the mode of fracture in pure cement paste, cement bonded rubber composite and rubber filled cement paste. It was found that cracks propagate through the rubber particle in rubber bonded cement composite while in unbonded rubber cement mix, the cracks propagate around the interface. The density and shrinkage measurements are also discussed.

Raghavan, D. [Howard Univ., Washington, DC (United States). Dept. of Chemistry; Tratt, K.; Wool, R.P. [Univ. of Illinois, Urbana, IL (United States). Dept. of Material Science and Engineering

1994-12-31

302

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

303

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

304

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

305

The nutritional value of some processed meat products in Malaysia.  

PubMed

Per capita consumption of meat and meat products in Malaysia more than doubled from 15.70 kg in 1970 to 35.71 kg in 1990. This increase in meat consumption is mainly due to the rapid development and wide acceptance of value added meat and poultry products amongst Malaysian consumers. Meat products such as burgers, sausages, hotdogs and nuggets are widely accepted and consumed by all ethnic groups at home as well as in the fast food restaurants. The significant expansion of the fast food industry and the increase consumption of processed meat products makes it necessary for a re-evaluation of the nutritional quality of popular meat products currently available in the market. This review paper described the quality of some processed meat products, their proximate composition, meat quality, use of non meat proteins and binders, and the use of additives in the formulation of burgers, frankfurters, nuggets, bologna, chicken and beef balls. Preliminary results on the protein efficiency ratio of local meat products seemed favourable but this study is limited to only one laboratory. In vivo and in vitro protein digestibility studies indicated high values on the digestibility of locally manufactured meat products. Proximate analysis of the raw materials used in the formulation of such products showed many with high fat and low protein contents being utilized. The meat content was lower than the minimum amount stated by the food regulation. This paper concludes that due to lack of information and studies on the nutritional composition of processed meat products, concerned bodies should take positive steps to generate reliable data to elucidate the actual nutritional composition of such products. It is also observed that many by-products from the animal industry from non-conventional sources are increasingly being utilized in the manufacture of processed meat product. PMID:22692017

Babji, A S; Mohdyusof, S

1995-03-01

306

MCFC integrated system in a biodiesel production process  

NASA Astrophysics Data System (ADS)

The continuous increasing in biodiesel production by transesterification process is leading to an excess of glycerol production as a byproduct. The utilization of this huge amount of glycerol appears as a not easy solvable problem and thus several authors have proposed alternative ways. The integration of the main production process with a glycerol feed molten carbonate fuel cells bottoming cycle, to satisfy plant energy requirements, seems to be one of the most promising one. The proposed paper reports the main results obtained by authors in the framework of an investigation on a possible use of glycerol as energy sources for a real pilot plant for biodiesel production. An overall evaluation of worldwide biodiesel production plants was made and especially about the production capacity in European Union in the last decade. To make a more detailed study, authors were taken into account a real production plant. After a preliminary step, purported to plant mass and energy flows determination, authors considered the integration of a bottoming cycle based on: (i) steam reforming of glycerol for syn-gas production; (ii) molten carbonate fuel cells (MCFC) system supplied by syn-gas for heat and electricity production. A mathematical model, based on experimental data, has been developed to calculate mass and energy balances for the proposed plant lay-out as well as plant energy efficiency enhancement has been determined. Results have evidenced the feasibility of this process and demonstrated that plant integrated with bottoming cycle can reach a very high level of energy self-production.

Urbani, F.; Freni, S.; Galvagno, A.; Chiodo, V.

2011-03-01

307

Certain Calcium Aluminate Cement and Cement Clinker from France. Investigation No. 731-TA-645 (Final). (May 1994).  

National Technical Information Service (NTIS)

Contents: Determination and views of the Commission; Determination, Views of the Commission; Information obtained in the investigation; Introduction, Background, Previous Commission investigations concerning cement, The products, The nature and extent of ...

1994-01-01

308

A practical approach to the interpretation of cement bond logs  

SciTech Connect

The Cement Bond Log has been controversial since its inception. Despite its potential, it is possibly the most maligned logging service available to the industry. Effective zone isolation between permeable intervals in a well requires a cement sheath over an appreciable vertical interval. It is necessary for the annular cement sheath to provide an effective hydraulic seal in order to withstand subsequent completion and production operations. The oil industry has used wireline well logs to detect the presence or absence of cement behind pipe for more than twenty years. Users have attempted, not always successfully, to evaluate the effectiveness of cement bond to both pipe and formation, ostensibly, with Cement Bond Logs. Cement Bond Logs do not mislead. Poor interpretation habits mislead. Knowledge of the well completion and the inherent physical restraints placed upon the log measurements is needed in order to properly evaluate the log. The purpose here is to dispel some of the myths created by misguided interpretation practices. Examples of Cement Bond Logs which fall into this category are presented.

Bigelow, E.L.

1985-03-01

309

A practical approach to the interpretation of cement bond logs  

SciTech Connect

The cement bond log has been controversial since its inception. Despite its potential, it is possibly the most maligned logging service available to the industry. Effective zone isolation between permeable intervals in a well requires a cement sheath over an appreciable vertical interval. It is necessary for the annular cement sheath to provide an effective hydraulic seal to withstand subsequent completion and production operations. The oil industry has used wireline well logs to detect the presence or absence of cement behind pipe for more than 20 years. Users have attempted, not always successfully, to evaluate the effectiveness of cement bond to both pipe and formation with cement bond logs. Cement bond logs do not mislead. Poor interpretation habits mislead. Knowledge of the well completion and the inherent physical restraints placed on the log measurements is needed to evaluate the log properly. The purpose here is to dispel some of the myths created by misguided interpretation practices. Examples of cement bond logs that fall into this category are be presented.

Bigelow, E.L.

1985-07-01

310

Cement Mason's Curriculum. Instructional Units.  

ERIC Educational Resources Information Center

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

Hendirx, Laborn J.; Patton, Bob

311

Communication Cement-based thermocouples  

E-print Network

Communication Cement-based thermocouples Sihai Wen, D.D.L. Chung* Composite Materials Research Received 31 May 2000; accepted 4 August 2000 Abstract A cement-based thermocouple in the form of a junction between dissimilar cement pastes and exhibiting thermocouple sensitivity 70 7 mV/°C is provided

Chung, Deborah D.L.

312

Performance Cements Focus on Sustainability  

E-print Network

.5%, reductions of: Raw materials use, 1.6 million tons Energy use, 11.8 trillion BTUs CO2 emissions, 2.7 million the beneficial re-use of byproducts Maximize use of materials with low associated CO2 emissions Blended cements with low associated CO2 emissions Blended cements versus separate components Limestone in cement #12;3 High

313

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...

314

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

315

7 CFR 926.11 - Processed cranberries or cranberry products.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 2010-01-01 false Processed cranberries or cranberry products. 926.11 Section 926.11 Agriculture...REPORTING AND RECORDKEEPING REQUIREMENTS APPLICABLE TO CRANBERRIES NOT SUBJECT TO THE CRANBERRY MARKETING ORDER...

2010-01-01

316

The Idaho Chemical Processing Plant Product Denitrator Upgrade  

SciTech Connect

The upgrade and redesign of a fluidized-bed denitrator for production of uranium trioxide from uranyl nitrate solution is discussed. The success of the project in improving process efficiency and personnel safety is also addressed based on subsequent operation.

N /A

1982-05-01

317

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

318

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

319

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

320

Optimizing product life cycle processes in design phase  

NASA Astrophysics Data System (ADS)

Life cycle concepts do not only serve as basis in assisting product developers understand the dependencies between products and their life cycles, they also help in identifying potential opportunities for improvement in products. Common traditional concepts focus mainly on energy and material flow across life phases, necessitating the availability of metrics derived from a reference product. Knowledge of life cycle processes won from an existing product is directly reused in its redesign. Depending on sales volume nevertheless, the environmental impact before product optimization can be substantial. With modern information technologies today, computer-aided life cycle methodologies can be applied well before product use. On the basis of a virtual prototype, life cycle processes are analyzed and optimized, using simulation techniques. This preventive approach does not only help in minimizing (or even eliminating) environmental burdens caused by product, costs incurred due to changes in real product can also be avoided. The paper highlights the relationship between product and life cycle and presents a computer-based methodology for optimizing the product life cycle during design, as presented by SFB 392: Design for Environment - Methods and Tools at Technical University, Darmstadt.

Faneye, Ola. B.; Anderl, Reiner

2002-02-01

321

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

NASA Astrophysics Data System (ADS)

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

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

1981-05-01

322

Membrane catalysis in the dehydrogenation and hydrogen production processes  

NASA Astrophysics Data System (ADS)

Data on the applications of membrane catalysis in the dehydrogenation of organic compounds and hydrogen production are analyzed and generalized. It is shown that the integration of membrane reactors into existing plants is necessary for production of hydrogen of high purity. The steam reforming and oxidative reforming of methane and steam reforming of light alcohols seem to be the most promising processes for hydrogen production in membrane reactors. The bibliography includes 165 references.

Basov, N. L.; Ermilova, M. M.; Orekhova, N. V.; Yaroslavtsev, Andrei B.

2013-04-01

323

COORDINATION AT DIFFERENT STAGES OF THE PRODUCT DESIGN PROCESS  

E-print Network

COORDINATION AT DIFFERENT STAGES OF THE PRODUCT DESIGN PROCESS Antonio J. Bailetti*, John R addresses the following question: how does the coordination challenge faced by managers change over the life of time bound projects such as product design. We use coordination structure, an approach to modeling

Callahan, John

324

Standardization of Components, Products and Processes with Data Mining  

E-print Network

1 Standardization of Components, Products and Processes with Data Mining Bruno AGARD Département de - 1527, USA andrew-kusiak@uiowa.edu ABSTRACT Data mining offers tools for extracting knowledge from databases. This paper discusses applications of data mining in standardization of components, products

Kusiak, Andrew

325

Optimal biodiesel production using bioethanol: Towards process integration.  

E-print Network

Optimal biodiesel production using bioethanol: Towards process integration. Kristen Severson Ave. Pittsburgh PA 15213 Abstract. In this paper we optimize the production of biodiesel to recover the ethanol, separate the polar and non polar phases and purify the glycerol and biodiesel

Grossmann, Ignacio E.

326

Autonomous production cell for ?m- and nm-processing  

NASA Astrophysics Data System (ADS)

Shorter life time cycles of products, increasing workpiece variety and declining lot sizes demand for a closed processing chain which enables the economic production of variable products in the future. A new type of manufacturing concept for the production of the 21st century is lined out by the design of an "Autonomous Production Cell." Applied to and designed for manufacturing with laser radiation this concept shows completely new ways in comparison to former manufacturing procedures. The manufacturing processes in the Autonomous Production Cell start with a production oriented design and planning of the manufacturing procedure is including sensor controlled processing of the workpieces with integrated quality management. The quality management detects failures in the manufacturing procedure and allows back-coupling to any preceding step by means of a multistage cascaded production controller. In comparison to former concepts the user is at all times integrated into the manufacturing procedure. The user can add his own competence and creativity. At the same time he is being relieved by routine work and gets adequate help by the system in corresponding situations. The design of the components of the Autonomous Production Cell (design and planning tools, networking of sensors and actuators, user interface, etc.) has been performed as general as possible. This offers the possibility to transfer this concept with countable efforts to all the manufacturing with laser radiation such as welding, cutting, surface treatment, freeforming, rapid prototyping, etc.

Kreutz, Ernst-Wolfgang; Boeske, Lars; Kaierle, Stefan; Mann, Stefan; Ortmann, Juergen; Willach, Jens

2003-07-01

327

Integrating artificial and human intelligence into tablet production process.  

PubMed

We developed a new machine learning-based method in order to facilitate the manufacturing processes of pharmaceutical products, such as tablets, in accordance with the Process Analytical Technology (PAT) and Quality by Design (QbD) initiatives. Our approach combines the data, available from prior production runs, with machine learning algorithms that are assisted by a human operator with expert knowledge of the production process. The process parameters encompass those that relate to the attributes of the precursor raw materials and those that relate to the manufacturing process itself. During manufacturing, our method allows production operator to inspect the impacts of various settings of process parameters within their proven acceptable range with the purpose of choosing the most promising values in advance of the actual batch manufacture. The interaction between the human operator and the artificial intelligence system provides improved performance and quality. We successfully implemented the method on data provided by a pharmaceutical company for a particular product, a tablet, under development. We tested the accuracy of the method in comparison with some other machine learning approaches. The method is especially suitable for analyzing manufacturing processes characterized by a limited amount of data. PMID:24970587

Gams, Matjaž; Horvat, Matej; Ožek, Matej; Luštrek, Mitja; Gradišek, Anton

2014-12-01

328

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

329

Energy Efficiency Improvement and Cost Saving Opportunities for Cement Making. An ENERGY STAR Guide for Energy and Plant Managers  

SciTech Connect

The cost of energy as part of the total production costs in the cement industry is significant, warranting attention for energy efficiency to improve the bottom line. Historically, energy intensity has declined, although more recently energy intensity seems to have stabilized with the gains. Coal and coke are currently the primary fuels for the sector, supplanting the dominance of natural gas in the 1970s. Most recently, there is a slight increase in the use of waste fuels, including tires. Between 1970 and 1999, primary physical energy intensity for cement production dropped 1 percent/year from 7.3 MBtu/short ton to 5.3 MBtu/short ton. Carbon dioxide intensity due to fuel consumption and raw material calcination dropped 16 percent, from 609 lb. C/ton of cement (0.31 tC/tonne) to 510 lb. C/ton cement (0.26 tC/tonne). Despite the historic progress, there is ample room for energy efficiency improvement. The relatively high share of wet-process plants (25 percent of clinker production in 1999 in the U.S.) suggests the existence of a considerable potential, when compared to other industrialized countries. We examined over 40 energy efficient technologies and measures and estimated energy savings, carbon dioxide savings, investment costs, and operation and maintenance costs for each of the measures. The report describes the measures and experiences of cement plants around the wold with these practices and technologies. Substantial potential for energy efficiency improvement exists in the cement industry and in individual plants. A portion of this potential will be achieved as part of (natural) modernization and expansion of existing facilities, as well as construction of new plants in particular regions. Still, a relatively large potential for improved energy management practices exists.

Galitsky, Christina; Worrell, Ernst; Galitsky, Christina

2008-01-01

330

Biodiversity, productivity and the temporal stability of productivity: patterns and processes  

E-print Network

deviation (r) of community biomass production (Lehman & Tilman 2000). Theory predicts that biodiversity canLETTER Biodiversity, productivity and the temporal stability of productivity: patterns and processes Forest I. Isbell,1 * H. Wayne Polley2 and Brian J. Wilsey1 1 Department of Ecology, Evolution

Wilsey, Brian J.

331

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

332

Access to Land Data Products Through the Land Processes DAAC  

Microsoft Academic Search

The Land Processes Distributed Active Archive Center (LP DAAC) was established as part of NASA's Earth Observing System (EOS) Data and Information System (EOSDIS) initiative to process, archive, and distribute land-related data collected by EOS sensors, thereby promoting the inter-disciplinary study and understanding of the integrated Earth system. The LP DAAC is responsible for archiving, product development, distribution, and user

A. L. Klaassen; C. K. Gacke

2004-01-01

333

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

334

PAPER PRODUCTION AND PROCESSING - OCCUPATIONAL EXPOSURE AND ENVIRONMENTAL RELEASE STUDY  

EPA Science Inventory

This report presents an analysis of chemicals and processes used during the production and processing of paper and paper goods with emphasis on the workplace exposure and environmental release of chemicals from these operations. Reviews of chemical substances in this report are i...

335

Hydrogen production by biological processes: a survey of literature  

Microsoft Academic Search

Hydrogen is the fuel of the future mainly due to its high conversion efficiency, recyclability and nonpolluting nature. Biological hydrogen production processes are found to be more environment friendly and less energy intensive as compared to thermochemical and electrochemical processes. They are mostly controlled by either photosynthetic or fermentative organisms. Till today, more emphasis has been given on the former

Debabrata Das; T. Nejat Veziro?lu

2001-01-01

336

Product and process innovation in the energy industry  

Microsoft Academic Search

The growth in the proportion of medium and light distillates in total petroleum product demand is forcing the oil refining industry to a process of supply adaptation by means of technological reconversion. In some countries this process is already advanced, while in others it is still at the starting point. As an alternative to technological reconversion, this adaptation may be

Francesco Gullì

1995-01-01

337

Glass ionomer cements  

Microsoft Academic Search

Glass ionomer cements have been used in pediatric restorative dentistry for 20 years. Their usefulness in pediatric restorative dentistry is preferential relative to other materi- als because of their fluoride release, chemical adhesion to tooth structure, and availability to use in a variety of clinical scenarios. This paper reviews the use of glass ionomer ma- terials in pediatric restorative dentistry.

Joel H. Berg

2002-01-01

338

Ionic liquid-based green processes for energy production.  

PubMed

To mitigate the growing pressure on resource depletion and environment degradation, the development of green processes for the production of renewable energy is highly required. As a class of novel and promising media, ionic liquids (ILs) have shown infusive potential applications in energy production. Aiming to offer a critical overview regarding the new challenges and opportunities of ILs for developing green processes of renewable energy, this article emphasises the role of ILs as catalysts, solvents, or electrolytes in three broadly interesting energy production processes from renewable resources, such as CO2 conversion to fuels and fuel additives, biomass pretreatment and conversion to biofuels, as well as solar energy and energy storage. It is expected that this article will stimulate a generation of new ideas and new technologies in IL-based renewable energy production. PMID:24553494

Zhang, Suojiang; Sun, Jian; Zhang, Xiaochun; Xin, Jiayu; Miao, Qingqing; Wang, Jianji

2014-10-20

339

Scale-down of the inactivated polio vaccine production process.  

PubMed

The anticipated increase in the demand for inactivated polio vaccines resulting from the success in the polio eradication program requires an increase in production capacity and cost price reduction of the current inactivated polio vaccine production processes. Improvement of existing production processes is necessary as the initial process development has been done decades ago. An up-to-date lab-scale version encompassing the legacy inactivated polio vaccine production process was set-up. This lab-scale version should be representative of the large scale, meaning a scale-down model, to allow experiments for process optimization that can be readily applied. Initially the separate unit operations were scaled-down at setpoint. Subsequently, the unit operations were applied successively in a comparative manner to large-scale manufacturing. This allows the assessment of the effects of changes in one unit operation to the consecutive units at small-scale. Challenges in translating large-scale operations to lab-scale are discussed, and the concessions that needed to be made are described. The current scale-down model for cell and virus culture (2.3-L) presents a feasible model with its production scale counterpart (750-L) when operated at setpoint. Also, the current scale-down models for the DSP unit operations clarification, concentration, size exclusion chromatography, ion exchange chromatography, and inactivation are in agreement with the manufacturing scale. The small-scale units can be used separately, as well as sequentially, to study variations and critical product quality attributes in the production process. Finally, it is shown that the scale-down unit operations can be used consecutively to prepare trivalent vaccine at lab-scale with comparable characteristics to the product produced at manufacturing scale. PMID:23192424

Thomassen, Yvonne E; van 't Oever, Aart G; Vinke, Marian; Spiekstra, Arjen; Wijffels, René H; van der Pol, Leo A; Bakker, Wilfried A M

2013-05-01

340

The JSC Engineering Directorate Product Peer Review Process  

NASA Technical Reports Server (NTRS)

The JSC Engineering Directorate has developed a Product Peer Review process in support of NASA policies for project management and systems engineering. The process complies with the requirements of NPR 7120.5, NPR 7123.1 and NPR 7150.2 and follows the guidance in NASA/SP-2007-6105. This presentation will give an overview of the process followed by a brief demonstration of an actual peer review, with audience participation.

Jenks, Kenneth C.

2009-01-01

341

Virtual Collaborative Simulation Environment for Integrated Product and Process Development  

NASA Technical Reports Server (NTRS)

Deneb Robotics is a leader in the development of commercially available, leading edge three- dimensional simulation software tools for virtual prototyping,, simulation-based design, manufacturing process simulation, and factory floor simulation and training applications. Deneb has developed and commercially released a preliminary Virtual Collaborative Engineering (VCE) capability for Integrated Product and Process Development (IPPD). This capability allows distributed, real-time visualization and evaluation of design concepts, manufacturing processes, and total factory and enterprises in one seamless simulation environment.

Gulli, Michael A.

1997-01-01

342

Testing Guide This testing guide is a product of an FHWA 17-state pooled fund: Material and Construction  

E-print Network

Construction of portland cement concrete pavements is a complex process. A small fraction of the concrete of America, March 2008 This material is one product of phase 3 of a multi-year effort supported by a Federal

343

Advanced product planning: a comprehensive process for systemic definition of new product requirements  

Microsoft Academic Search

This paper reports results of research into the definition of requirements for new consumer products––specifically, electro-mechanical\\u000a products. The research dealt with the derivation of design requirements that are demonstrably aligned with stakeholder needs.\\u000a The paper describes a comprehensive process that can enable product development teams to deal with statements of product requirements,\\u000a as originally collected through market research activities, in

Vassilis Agouridas; Alison Mckay; Henri Winand; Alan De Pennington

2008-01-01

344

7 CFR 915.141 - Handling avocados for commercial processing into products.  

... false Handling avocados for commercial processing into products. 915...141 Handling avocados for commercial processing into products. ...shall handle any avocados for commercial processing into...

2014-01-01

345

Impact of Wellbore Cement Degradation on CO2 Storage Integrity  

NASA Astrophysics Data System (ADS)

The sequestration of CO2 in underground geologic formations requires a thorough evaluation of potential leakage of the sequestered CO2 through the numerous existing wellbores which penetrate them. Leakage rates of less than 1% per 100 years have been deemed necessary for geologic sequestration to be viable. Well bores are of particular interest because the cement used to line and/or plug the well, may be vulnerable to acid attack. Injected CO2 will dissolve, becoming carbonic acid, which can readily react with calcium hydroxide and calcium silicate hydrate, key components in hardened cement. Laboratory experiments have been performed in order to determine the physical and chemical changes, as well as the rate of degradation of the cement under simulated sequestration reservoir conditions, including both aqueous and supercritical CO2. Upon exposure to aqueous CO2, hardened cement formed well-defined reaction zones by a 2-step process. The first step is the dissolution of Ca(OH) 2 (s) and subsequent precipitation of CaCO3 (s). The formation of CaCO3 (s) has been reported to decrease cement permeability and increase its compressive strength. The second step is the dissolution of CaCO3 (s) resulting in a leaching of calcium from the cement matrix. The resulting cement paste has a significant increase in porosity, is primarily composed of amorphous silica gel, and lacks structural integrity. Although it is clear that cement is degraded, the results of this study suggest that the reactions involved are slow. In fact, long term experiments show that the rate of degradation decreases over time, likely due to the precipitation of CaCO3 (s) within the pore space of the cement. This phenomenon should limit the negative impact that chemical degradation will have on well bores. Supercritical CO2 exposure (saturated with water vapor) led to a very different process by which CaCO3 (s) was deposited throughout the matrix and on the surface, rather than within an isolated reaction zone. Over the one-year time period of the experiments, this condition led to a smaller amount of total degradation than in the aqueous phase. However, in this case, there was no deceleration of the reaction observed. It is unlikely that the diffusion controlled degradation process observed in these experiments would lead to well failure in well completions that are well cemented with neat Portland cement (without additives). Further investigation is required to evaluate the effect of cement additives, fractures or channels in the cement, and geomechanical stress.

Kutchko, B.; Strazisar, B.; Lowry, G.; Dzombak, D.; Thaulow, N.

2007-12-01

346

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

347

Process development and evaluation for algal glycerol production. [Koor Process, Dunaliella parva  

SciTech Connect

An economically and technically feasible process is proposed for large-scale production of glycerol by means of a halophilic algae. This process provides an alternative route for glycerol production that is minimally dependent on fossil fuels and is, therefore, less sensitive to crude oil availability and price. The primary raw material, carbon dioxide from stack gas, is an inexpensive and renewable resource. Maximal utilization of solar energy is made not only in the glycerol synthesis steps but also in the product recovery system. Significant improvment in the process economics can be realized through further development of large-scale cultivation technology, and biomass distribution and collection machinery. 21 refs.

Chen, B.J.; Chi, C.H.

1981-06-01

348

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

349

By-Products Utilization  

E-print Network

...............................................................................................................39 #12;iii List of Tables Item Page Table 1 Stable Phases in Portland Cement Paste at Different p.3 Carbon Dioxide Sequestration, Concrete and other Cement- Based Products ..................................................................................................... 10 1.4 Claims by Industries for the Sequestration of CO2 in Cement- Based Products

Wisconsin-Milwaukee, University of

350

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. PMID:19837892

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

351

CO-PRODUCT ENHANCEMENT AND DEVELOPMENT FOR THE MASADA OXYNOL PROCESS PROCESS  

SciTech Connect

The focus of this project was an overall process improvement through the enhancement of the co-product streams. The enhancement of the process operations and co-products will increase both ethanol production and the value of other process outputs and reduces the amount of waste byproducts. This leads to a more economical and environmentally sound alternative to landfill disposal of municipal solid waste (MSW). These enhancements can greatly increase the commercial potential for the production of ethanol from MSW by the Masada CES OxyNol process. Both technological and economical issues were considered for steps throughout the conversion process. The research efforts of this project are varied but synergistic. The project investigated many of the operations involved in the Masada process with the overall goal of process improvements. The general goal of the testing was to improve co-product quality, improve conversions efficiencies, minimize process losses, increase energy efficiency, and mitigate process and commercialization risks. The project was divided into 16 subtasks as described in general terms below. All these tasks are interrelated but not necessarily interdependent.

Donald V. Watkins

2010-06-14

352

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

353

Processing Radio PSAs: Production Pacing, Arousing Content, and Age  

Microsoft Academic Search

This experiment uses the limited capacity model of mediated message processing (LC3MP) to investigate the effects of production pacing and arousing content in radio public service announcements (PSAs) on the emotional and cognitive responses of college-age and tween (9–12-year-olds) participants. The LC3MP predicts that both arousing content and production pacing should increase emotional arousal, physiological arousal, cognitive effort, and encoding

Annie Lang; Nancy Schwartz; Seungjo Lee; James Angelini

2007-01-01

354

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

355

Quotation for the Value Added Assessment during Product Development and Production Processes  

E-print Network

This communication is based on an original approach linking economical factors to technical and methodological ones. This work is applied to the decision process for mix production. This approach is relevant for costing driving systems. The main interesting point is that the quotation factors (linked to time indicators for each step of the industrial process) allow the complete evaluation and control of, on the one hand, the global balance of the company for a six-month period and, on the other hand, the reference values for each step of the process cycle of the parts. This approach is based on a complete numerical traceability and control of the processes (design and manufacturing of the parts and tools, mass production). This is possible due to numerical models and to feedback loops for cost indicator analysis at design and production levels. Quotation is also the base for the design requirements and for the choice and the configuration of the production process. The reference values of the quotation generate the base reference parameters of the process steps and operations. The traceability of real values (real time consuming, real consumable) is mainly used for a statistic feedback to the quotation application. The industrial environment is a steel sand casting company with a wide mix product and the application concerns both design and manufacturing. The production system is fully automated and integrates different products at the same time.

Alain Bernard; Nicolas Perry; Jean-Charles Delplace; Serge Gabriel

2010-11-26

356

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

357

Dry-ADU process for UO 2 production  

NASA Astrophysics Data System (ADS)

Scattered granular ammonium diuranate (ADU) products were prepared directly by reacting atomized liquid droplets of uranyl fluoride or uranyl nitrate with ammonia gas. After calcination in nitrogen and reduction with the steam-hydrogen gas, the ADU products were converted to UO 2 powders which were pelletized and then sintered for characterization. No waste liquid filtrate was generated in the process. The ADU product and UO 2 powder were easy-handling. Uranium dioxide powders with low fluorine content and good pelletizing and sintering properties were prepared.

Ching-Tsven, Huang

1992-12-01

358

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

359

Design of synthetic microbial communities for biotechnological production processes.  

PubMed

In their natural habitats microorganisms live in multi-species communities, in which the community members exhibit complex metabolic interactions. In contrast, biotechnological production processes catalyzed by microorganisms are usually carried out with single strains in pure cultures. A number of production processes, however, may be more efficiently catalyzed by the concerted action of microbial communities. This review will give an overview of organismic interactions between microbial cells and of biotechnological applications of microbial communities. It focuses on synthetic microbial communities that consist of microorganisms that have been genetically engineered. Design principles for such synthetic communities will be exemplified based on plausible scenarios for biotechnological production processes. These design principles comprise interspecific metabolic interactions via cross-feeding, regulation by interspecific signaling processes via metabolites and autoinducing signal molecules, and spatial structuring of synthetic microbial communities. In particular, the implementation of metabolic interdependencies, of positive feedback regulation and of inducible cell aggregation and biofilm formation will be outlined. Synthetic microbial communities constitute a viable extension of the biotechnological application of metabolically engineered single strains and enlarge the scope of microbial production processes. PMID:24943116

Jagmann, Nina; Philipp, Bodo

2014-08-20

360

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.

361

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.  

PubMed

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 ash is to be reused in cement; however, the relationship between washed fly ash properties and chloride reduction by calcination is not well understood. This study used washed residues of three types of fly ash-raw fly ash (RFA) from the boiler or economizer of an incineration system, fly ash collected in a bag filter injected with calcium hydroxide (Ca(OH)2) for acid removal (CaFA), and fly ash collected in a bag filter injected with sodium bicarbonate (NaHCO3) for acid removal (NaFA)-in calcination experiments with varying temperature (400-1100 degrees C) and atmosphere (100% nitrogen [N2] at 25 mL/min or 10% oxygen [O2] [90% N2] at fluxes of 25, 50, and 75 mL/min). From the perspective of chloride reduction, heating to 1000 degrees C with 1-hr heating time, 1-hr holding time, and an atmosphere of 10% O2/90% N2 was most suitable for calcination. Under these conditions, chloride levels were reduced by 91, 52, and 96% in washed residues of RFA, CaFA, and NaFA, respectively. Among the washed residues, the weight of the washed residue of NaFA decreased the most. PMID:21850828

Zhu, Fenfen; Takaoka, Masaki; Oshita, Kazuyuki; Morisawa, Shinsuke

2011-07-01

362

An alternative to Portland Cement for waste encapsulation--the calcium sulfoaluminate cement system.  

PubMed

Currently, Portland Cement (PC) is used extensively in the solidification/stabilisation of a wide variety of wastes. In the nuclear industry, low and intermediate level radioactive wastes are encapsulated or immobilised within composite PC cement systems based on high replacement with blast furnace slag or fly ash. However, the high alkalinity of these PC-based systems will corrode reactive metals found in some wastes releasing hydrogen and forming expansive corrosion products. Alternative cement systems could provide a different hydration chemistry, which would allow wastes containing these metals to be encapsulated with lower reactivity. Calcium sulfoaluminate (CS A) cement is one such cement. It combines economy of cost and low emission of CO(2) with rapid strength gain and compatibility with other construction materials. Hydration provides an internal pore solution where the pH is considerably lower than that of PC. The main hydration product, ettringite, can incorporate a number of ions into its crystal structure, making it an ideal candidate for waste immobilisation. This paper details some results from a commercial CS A system that examines aspects of mixing, hydration of different formulations and aluminium corrosion behaviour. The fluidity of mixes can be adjusted by changing the formulations. All designed mixes were set within 24 h with little bleeding and the pH values were in the range of 10-11.5. In addition, a significant reduction in Al corrosion was observed compared to a composite OPC system. Although these results provide encouragement for the idea that CS A cement can provide a possible alternative to PC in the immobilisation of difficult and reactive wastes, further investigation is needed. PMID:16406289

Zhou, Q; Milestone, N B; Hayes, M

2006-08-10

363

Evaluation and Risk Analysis on Henan Agricultural Products Processing Enterprises  

Microsoft Academic Search

\\u000a Risk analysis and evaluation is the key problem in risk management, the outcome of assessment directly affects business policy\\u000a and enterprises development. This article mainly studies qualitative issues in quantitative analysis on risk problems among\\u000a present agricultural products processing enterprises by applying a simple and flexible decision-making method, the fuzzy analytic\\u000a hierarchy process method, through analyzing the total level weight,

Rui Wang; Keqin Su; Yawei Wang; Baosong Liang

364

Two-Photon Processes for Particle Production at High Energies  

Microsoft Academic Search

The literature of the past three years on the two-photon process for particle production e+\\/-+e- -->e+\\/-+gamma*+e- +gamma*-->e+\\/-+e-+X (where X is any C=+ state) or p+p-->X1+gamma*+X2+gamma*-->X1+X2+mu++mu- (where X1,X2 are hadron states) is reviewed in some detail. Both the theoretical aspects and the experimental feasibility of various processes are discussed especially for experimentalists' convenience.

Hidezumi Terazawa

1973-01-01

365

A novel framework for simultaneous separation process and product design  

Microsoft Academic Search

The objective of this paper is to introduce a systematic framework for simultaneous solution of process\\/product design problems related to separation. This framework is based on the recently developed property clustering approach that allows one to perform design calculations on a component-free (or composition-free) basis. Removing the composition dependency from the design problem enables the simultaneous consideration of process and

M. R. Eden; S. B. Jørgensen; R. Gani; M. M. El-Halwagi

2004-01-01

366

Soil Production and Erosion Rates and Processes in Mountainous Landscapes  

NASA Astrophysics Data System (ADS)

We focus here on high-relief, steeply sloped landscapes from the Nepal Himalaya to the San Gabriels of California that are typically thought to be at a critical threshold of soil cover. Observations reveal that, instead, there are significant areas mantled with soil that fit the conceptual framework of a physically mobile layer derived from the underlying parent material with some locally-derived organic content. The extent and persistence of such soils depends on the long-term balance between soil production and erosion despite the perceived discrepancy between high erosion and low soil production rates. We present cosmogenic Be-10-derived soil production and erosion rates that show that soil production increases with catchment-averaged erosion, suggesting a feedback that enhances soil-cover persistence, even in threshold landscapes. Soil production rates do decline systematically with increasing soil thickness, but hint at the potential for separate soil production functions for different erosional regimes. We also show that a process transistion to landslide-dominated erosion results in thinner, patchier soils and rockier topography, but find that there is no sudden transition to bedrock landscapes. Our landslide modeling is combined with a detailed quantification of bedrock exposure for these steep, mountainous landscapes. We also draw an important conclusion connecting the physical processes producing and transporting soil and the chemical processes weathering the parent material by measuring parent material strength across three different field settings. We observe that parent material strength increases with overlying soil thickness and, therefore, the weathered extent of the saprolite. Soil production rates, thus, decrease with increasing parent material competence. These observation highlight the importance of quantifying hillslope hydrologic processes where such multi-facted measurements are made.

Heimsath, A. M.; DiBiase, R. A.; Whipple, K. X.

2012-12-01

367

A unique experience with foamed cement  

SciTech Connect

An extensive laboratory program showed that foamed cement was the only technically feasible solution to prepare a floating cement plug for solving severe lost circulation problems in big caverns. The technique had, however, to be adapted to fit well conditions that are relatively unusual in the oil field: the cement slurry should not become diluted and destabilized upon exiting the drill pipe and entering the 60-plus inches wellbore and the huge caves, several feet in radius, both filled with sea water. Moreover, the foam had to remain stable, even when surrounded by large volume of water, until cement setting. Therefore a technique of using protective fluids was devised. In addition, logistics dictated the use of compressed air rather than nitrogen to prepare the foamed slurry. Therefore special gas metering and regulation devices were used for the first time in the oil field in order to automate the process and get a perfect control of the slurry density whatever the slurry mixing and pumping rates. Before field implementation, the metering and regulation device was successfully yard tested, the gas phase being supplied by nitrogen bottles. The successful field implementation with air compressors, together with the protective fluid technique to combat lost circulation in loose coral reef and in highly fractured dolomitic formation, is described.

Piot, B.; Ferriere, R.; Fraboulet, B.

1994-12-31

368

The long-run dynamics of product and process innovations for a multi-product monopolist  

Microsoft Academic Search

This paper introduces the dynamical framework which combines product and process innovations. The model contributes to the theoretical literature on innovations in two ways. First, it permits for the simultaneous dynamics of both types of innovations which is rarely considered in the literature. Second, the products being generated by the innovations are heterogeneous in their investment characteristics. This allows for

Anton Bondarev

2012-01-01

369

The long run Dynamics of heterogeneous Product and Process Innovations for a Multi Product Monopolist  

Microsoft Academic Search

This paper introduces the dynamical framework which combines product and process innovations. The model contributes to the theoretical literature on innovations in two ways. First, it permits for the simultaneous dynamics of both types of innovations which is rarely considered in the literature. Second, the products being generated by the innovations are heterogeneous in their investment characteristics. This allows for

Anton A. Bondarev

2010-01-01

370

Biodegradation of dental composites/glass-ionomer cements.  

PubMed

Studies of the degradation processes, types of tests, and measurements and analyses of substances leaching out from resin-based composite materials and glass-ionomer cements are reviewed. For both types of materials, the initial release rate rapidly decreases to a low, but nearly constant, level. For composites, various types of degradation processes have been demonstrated. Elements from filler particles and degradation products from the resin (e.g., formaldehyde) leak out. Many substances are not properly identified. It is, however, difficult for in vitro and in vivo degradation to be compared. For glass ionomers, a total disintegration of a surface layer is observed, together with a slow release of elements from the bulk. Of the elements released, fluoride is the most interesting. Marked differences have been shown between in vitro and in vivo solubility tests. PMID:1292463

Oilo, G

1992-09-01

371

Polymer reinforcement of cement systems  

Microsoft Academic Search

In the last couple of decades several cement- and concrete-based composites have come into prominence. Of these, cement-polymer composites, like cement-fibre composites, have been recognised as very promising, and considerable research and development on their properties, fabrication methods and application are in progress. Of the three types of concrete materials which incorporate polymers to form composites, polymer impregnated concrete forms

R. Narayan Swamy

1979-01-01

372

Cement penetration after patella venting.  

PubMed

There is a high rate of patellofemoral complications following total knee arthroplasty. Optimization of the cement-bone interface by venting and suction of the tibial plateau has been shown to improve cement penetration. Our study was designed to investigate if venting the patella prior to cementing improved cement penetration. Ten paired cadaver patellae were allocated prior to resurfacing to be vented or non-vented. Bone mineral density (BMD) was measured by DEXA scanning. In vented specimens, a 1.6 mm Kirschner wire was used to breach the anterior cortex at the center. Specimens were resurfaced with standard Profix instrumentation and Versabond bone cement (Smith and Nephew PLC, UK). Cement penetration was assessed from Faxitron and sectioned images by a digital image software package (ImageJ V1.38, NIH, USA). Wilcoxon rank sum test was used to assess the difference in cement penetration between groups. The relationship between BMD and cement penetration was analyzed by Pearson correlation coefficient. There was a strong negative correlation between peak BMD and cement penetration when analyzed independent of experimental grouping (r(2)=-0.812, p=0.004). Wilcoxon rank sum testing demonstrated no significant difference (rank sum statistic W=27, p=0.579) in cement penetration between vented (10.53%+/-4.66; mean+/-std dev) and non-vented patellae (11.51%+/-6.23; mean+/-std dev). Venting the patella using a Kirschner wire does not have a significant effect on the amount of cement penetration achieved in vitro using Profix instrumentation and Versabond cement. PMID:19010682

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

2009-01-01

373

Natural cement and monumental restoration  

Microsoft Academic Search

Natural cement, called “Roman” cement, was invented at the end of the 19th century and played an important role in the development\\u000a of civil engineering works until the 1860s. More surprisingly, it was also used to restore historic buildings, such as gothic\\u000a cathedrals. This paper deals with the mineralogy and the durability of natural cement in the particular case of

C. Gosselin; V. Verges-Belmin; A. Royer; G. Martinet

2009-01-01

374

Abrasive wear of cemented carbides  

SciTech Connect

Cemented carbides are used for a wide variety of applications where wear is a problem. Usually the wear of the cemented carbides is a combination of metal-to-metal and abrasion. Wear can occur at room or elevated temperatures. This research summarizes initial research to understand the abrasive wear of various cemented carbides (various grain sizes, carbide types, carbide grain sizes and binder compositions) in terms of absolute material removal rates and material removal mechanisms.

Hawk, Jeffrey A.; Wilson, Rick D.

2003-10-01

375

Insect natural products and processes: New treatments for human disease  

Microsoft Academic Search

In this overview, some of the more significant recent developments in bioengineering natural products from insects with use or potential use in modern medicine are described, as well as in utilisation of insects as models for studying essential mammalian processes such as immune responses to pathogens. To date, insects have been relatively neglected as sources of modern drugs although they

Norman A. Ratcliffe; Cicero B. Mello; Eloi S. Garcia; Tariq M. Butt; Patricia Azambuja

2011-01-01

376

NATO/CCMS PILOT STUDY - CLEAN PRODUCTS AND PROCESSES  

EPA Science Inventory

The proposed objective of the NATO/CCMS Pilot on clean products and processes is to facilitate further gains in pollution prevention, waste minimization, and design for the environment. It is anticipated that the free exchange of knowledge, experience, data, and models will fost...

377

Discourse Processes and Products: Land Surveyors in Hong Kong  

ERIC Educational Resources Information Center

The study reported in this paper aims to provide a description of professional communication pertaining to land surveying project management in Hong Kong, achieved through a comprehensive analysis of both workplace discourse processes and products. The study, situated in Hong Kong, represents a collaborative effort between English and Land…

Cheng, Winnie; Mok, Esmond

2008-01-01

378

The Creative Product and Process in Computer-Mediated Groups  

ERIC Educational Resources Information Center

The effects of information technology on the creative performance in small groups were examined. An experimental 3 x 2 design was used in order to assess the effects of Group Communication Support System (GCSS) and perceived usefulness on the creative product and the creative process. A chat, a video conference and a face-to-face group were…

Kristensson, Per; Norlander, Torsten

2003-01-01

379

INTEGRATING PROCESS, PRODUCT, AND PURPOSE: THE ROLE OF INSTRUCTION  

Microsoft Academic Search

Writing is a complex domain, and educators disagree about which aspects of writing should be emphasized and how it should be taught. A balanced point of view takes into account process, product, and purpose and acknowledges both the author and secretary roles. First, teachers should develop in the young writer three general understandings: that writing is a communicative function, that

Stephen L. Isaacson

1994-01-01

380

Software Product and Process Assessment through Profile-Based Evaluation  

Microsoft Academic Search

Software entities (software products or processes) are characterized by many attributes, each one in its turn can be measured by one or more measures. In several cases the software entities have to be evaluated as a whole, thus raising the problem of aggregating measures to give an overall, single view on the software entity. This paper presents a method to

Maurizio Morisio; Ioannis Stamelos; Alexis Tsoukiàs

2003-01-01

381

High-Level waste process and product data annotated bibliography  

SciTech Connect

The objective of this document is to provide information on available issued documents that will assist interested parties in finding available data on high-level waste and transuranic waste feed compositions, properties, behavior in candidate processing operations, and behavior on candidate product glasses made from those wastes. This initial compilation is only a partial list of available references.

Stegen, G.E.

1996-02-13

382

INPUT SUBSTITUTION AND DEMAND IN THE WATER SUPPLY PRODUCTION PROCESS  

EPA Science Inventory

The structure of input demand for U.S. water utilities is analyzed by estimating a translog cost function. An important feature of the model includes the multiproduct specification of the water supply production process. Operating variables are also specified to include capacity ...

383

Language Production and Reception: A Processability Theory Study  

ERIC Educational Resources Information Center

Pienemann's Processability Theory (PT) predicts an order of emergence of morphosyntactic elements in second language (L2) production data. This research investigates whether the same order of emergence can be detected in L2 reception data, specifically, data from a timed audio grammaticality judgment task (GJT). The results from three related…

Spinner, Patti

2013-01-01

384

$^{180}$Ta production in the classical s-process  

E-print Network

The production and survival of the quasistable isomer $^{180}$Ta during the stellar nucleosynthesis has remained a matter of discussion for years. A careful analysis of the available experimental data and theoretical calculations enabled us to reproduce the observed solar abundance of $^{180}$Ta in the classical s-process ($kT=28$ keV -- 33 keV).

Markus Loewe; Petr Alexa; Jorrit de Boer; Michael Wuerkner

2002-07-04

385

A dynamic model of process and product innovation  

Microsoft Academic Search

This article reports results from empirical tests of relationships between the pattern of innovation within a firm and certain of the firm's characteristics: the stage of development of its production process and its chosen basis of competition. The hypothesized relationships posed for the present investigation are a synthesis of prior research by the present authors on two distinct but complementary

James M Utterback; William J Abernathy

1975-01-01

386

Carburization process rate in production of synthetic cast iron  

Microsoft Academic Search

Purpose: The main goal of the paper was to determine the possibility of synthetic cast iron production on base of steel and process scraps as well as the carburization effectiveness, realized with three methods - fully described in main text. Design\\/methodology\\/approach: Each of described methods has undoubted advantages but also has a number of disadvantages. In foundry engineering practice the

K. Janerka; D. Bartocha; J. Szajnar

387

Simulation of the C5 Aliphatic Petroleum Resins Production Process  

Microsoft Academic Search

Petroleum resins are used widely in many industries. They are solvable in most of aromatic and aliphatic solvents. There are different grades of petroleum resins from dark and viscose liquids to bright and hard ones. They are used mostly in the adherent industry as binder. In this article the production process of aliphatic petroleum resin is simulated based on the

B. Berahman; B. Dabir; S. Sadeghpour

2010-01-01

388

Cementation of Upper Miocene reefs in western Mediterranean  

SciTech Connect

Coral reefs in the western Mediterranean (southeast Spain, Balearic Island, northern Morocco, Sicily, and Italy) show a wide variety of cement types, ranging from completely tight, well-cemented, to poorly cemented reefs with most of the primary porosity still preserved. Cementation processes in those coral reefs appear to be controlled to a great extent by repeated changes of relative sea levels and regional variations of seawater chemistry. Reef progradation occurred during four to six (or more) important sea level changes, resulting in complicated geometric relationships of reef complexes and their freshwater lenses. Progradation occurred during sea level rises and falls and is reflected in abrupt escarpments in some field localities, generally separated by important terraced erosional surfaces. Various types of aragonitic isopachous cement fringes of marine origin, 0.1 to 1.5 cm (.04 to .6 in.) thick, are well preserved in some localities. This is probably due to subsequent plugging by gypsum cement during the Messinian salinity crises. Another possible effect of salinity fluctuations is the abundance of thick crusts of peletoidal, micrite cement of marine origin, locally forming about three-fourths of the volume of the reef core.

Esteban, M.; Calvet, F.

1983-03-01

389

Indigenous microorganisms production and the effect on composting process  

NASA Astrophysics Data System (ADS)

In this study, production of indigenous microorganisms (IMO) and effect on addition of IMO in composting process were done. Production of IMO was done in a series of steps to allow propagation of beneficial microorganisms. Effect of IMO addition in composting process was investigated by having 4 treatments; 1) rice straw without IMO nor manure and rice bran, 2) rice straw with IMO only, 3) rice straw with manure and rice bran, 4) rice straw with IMO, manure and rice bran. Production of IMO using cooked rice yields white molds. Addition of IMO during composting did not affect temperature increment. However, there were differences in numbers of microorganisms found during each stages of composting. Initial composting stage was dominated by mesophilic bacteria and actinomycetes, followed by thermophilic bacteria and later by actinomycetes upon composting completion. In conclusion, this study showed that IMO addition in composting increased microorganisms which are responsible in organic decomposition.

Abu-Bakar, Nurul-Ain; Ibrahim, Nazlina

2013-11-01

390

Quality control throughout the production process of infant food.  

PubMed

The manufacture of infant food is a highly complex process and needs an effective quality control beyond classical in-process parameters and a final microbiological analysis. To ensure a safe end -product, various tools, such as the Hazard Analysis Critical Control Points (HACCP), have been developed to facilitate the management of food safety. Every single infant formula ingredient must have an excellent quality and safety approach because even if an ingredient is used in very small quantities in a single product, serious consequences may arise if the quality and product safety are not taken seriously by the ingredient manufacturer. The purpose of this article was twofold: firstly, to briefly describe existing Quality Management Systems and, secondly, to highlight the consequences of non-quality. PMID:22699770

Hamrin, Pia; Hoeft, Birgit

2012-01-01

391

[Allergy to bone cement components].  

PubMed

Intolerance reactions to endoprostheses may lead to allergological diagnostics, which focus mainly on metal allergy. However, bone cement may also contain potential allergens, e.g. acrylates and additives such as benzoyl peroxide (BPO), N,N-dimethyl-p-toluidine, hydroquinone, and antibiotics (particularly gentamicin). In the Munich implant allergy clinic, we found that 28 of 113 patients (24.8%) with cemented prostheses had contact allergies to bone cement components, mostly to gentamicin (16.8%) and BPO (8.0%). The clinical significance of test results cannot always be shown, but we still recommend including bone cement components in the allergological diagnostics of suspected hypersensitivity reactions to arthroplasty. PMID:18227996

Thomas, P; Schuh, A; Eben, R; Thomsen, M

2008-02-01

392

Oxygen production on the Lunar materials processing frontier  

NASA Technical Reports Server (NTRS)

During the pre-conceptual design phase of an initial lunar oxygen processing facility, it is essential to identify and compare the available processes and evaluate them in order to ensure the success of such an endeavor. The focus of this paper is to provide an overview of materials processing to produce lunar oxygen as one part of a given scenario of a developing lunar occupation. More than twenty-five techniques to produce oxygen from lunar materials have been identified. While it is important to continue research on any feasible method, not all methods can be implemented at the initial lunar facility. Hence, it is necessary during the pre-conceptual design phase to evaluate all methods and determine the leading processes for initial focus. Researchers have developed techniques for evaluating the numerous proposed methods in order to suggest which processes would be best to go to the Moon first. As one section in this paper, the recent evaluation procedures that have been presented in the literature are compared and contrasted. In general, the production methods for lunar oxygen fall into four categories: thermochemical, reactive solvent, pyrolytic, and electrochemical. Examples from two of the four categories are described, operating characteristics are contrasted, and terrestrial analogs are presented when possible. In addition to producing oxygen for use as a propellant and for life support, valuable co-products can be derived from some of the processes. This information is also highlighted in the description of a given process.

Altenberg, Barbara H.

1992-01-01

393

Drying\\/hydration in cement pastes during curing  

Microsoft Academic Search

As concrete cures in the field, there is a constant competition for the mixing water between evaporation and hydration processes.\\u000a Understanding the mechanisms of water movement in the drying\\/hydrating cement paste is critical for designing curing systems\\u000a and specialized rendering materials, as well as for selecting repair materials and methodologies. In this work, X-ray absorption\\u000a measurements indicate that fresh cement

D. P. Bentz; K. K. Hansen; H. D. Madsen; F. Vallée; E. J. Griesel

2001-01-01

394

Evaluation of steel furnace slags as cement additives  

SciTech Connect

Chemical and physical properties and strength development have been studied for six granulated steel furnace slags from the normal steelmaking process. This paper reports results of research performed to develop cement mixture proportions using these slags. The influence of slag proportions, specific surface, and water demand on compressive strength and bulk density of cement blends are presented in this paper. The different test results, which were compared with the Turkish Standards, in general, were found to be within the limits.

Tuefekci, M.; Demirbas, A.; Genc, H. [Technical Univ. of the Black Sea, Trabzon (Turkey)] [Technical Univ. of the Black Sea, Trabzon (Turkey)

1997-11-01

395

27 CFR 40.1 - Manufacture of tobacco products, cigarette papers and tubes, and processed tobacco.  

Code of Federal Regulations, 2010 CFR

...false Manufacture of tobacco products, cigarette papers and tubes, and processed tobacco...TOBACCO MANUFACTURE OF TOBACCO PRODUCTS, CIGARETTE PAPERS AND TUBES, AND PROCESSED TOBACCO...1 Manufacture of tobacco products, cigarette papers and tubes, and processed...

2010-04-01

396

27 CFR 41.1 - Importation of tobacco products, cigarette papers and tubes, and processed tobacco.  

Code of Federal Regulations, 2010 CFR

...false Importation of tobacco products, cigarette papers and tubes, and processed tobacco...TOBACCO IMPORTATION OF TOBACCO PRODUCTS, CIGARETTE PAPERS AND TUBES, AND PROCESSED TOBACCO...1 Importation of tobacco products, cigarette papers and tubes, and processed...

2010-04-01

397

7 CFR 58.738 - Pasteurized process cheese spread and related products.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 false Pasteurized process cheese spread and related products. 58.738...Products § 58.738 Pasteurized process cheese spread and related products. Shall...Standards of Identity for Pasteurized Process Cheese Spreads, Food and Drug...

2010-01-01

398

Titanium Metal Powder Production by the Plasma Quench Process  

SciTech Connect

The goals of this project included the scale-up of the titanium hydride production process to a production rate of 50 kg/hr at a purity level of 99+%. This goal was to be achieved by incrementally increasing the production capability of a series of reactor systems. This methodic approach was designed to allow Idaho Titanium Technologies to systematically address the engineering issues associated with plasma system performance, and powder collection system design and performance. With quality powder available, actual fabrication with the titanium hydride was to be pursued. Finally, with a successful titanium production system in place, the production of titanium aluminide was to be pursued by the simultaneously injection of titanium and aluminum precursors into the reactor system. Some significant accomplishments of the project are: A unique and revolutionary torch/reactor capable of withstanding temperatures up to 5000 C with high thermal efficiency has been operated. The dissociation of titanium tetrachloride into titanium powder and HC1 has been demonstrated, and a one-megawatt reactor potentially capable of producing 100 pounds per hour has been built, but not yet operated at the powder level. The removal of residual subchlorides and adsorbed HC1 and the sintering of powder to form solid bodies have been demonstrated. The production system has been operated at production rates up to 40 pounds per hour. Subsequent to the end of the project, Idaho Titanium Technologies demonstrated that titanium hydride powder can indeed be sintered into solid titanium metal at 1500 C without sintering aids.

R. A. Cordes; A. Donaldson

2000-09-01

399

History and some potentials of oil shale cement  

SciTech Connect

The utilization of oil shale as a cement component is discussed. It was investigated in America and Europe during World War I. Additional development occurred in Western Europe, Russia, and China during the 1920s and 1930s. World War II provided further development incentives and a relatively mature technology was in place in Germany, Russia, and China prior to 1980. The utilization of oil shale in cement has taken a number of different paths. One approach has been to utilize the energy in the oil shale as the principal source for the cement plant and to use the combusted shale as a minor constituent of the plant's cement product. A second approach has been to use the combusted shale as a class C or cementitious fly-ash component in portland cement concrete. Other approaches utilizing eastern oil shale have been to use the combusted oil shale with additives as a specialty cement, or to cocombust the oil shale with coal and utilize the sulfur-rich combustion product.

Knutson, C.F.; Smith, R.P.; Russell, B.F. (Idaho National Engineering Lab., Idaho Falls, ID (USA))

1989-01-01

400

Microstructure and microanalysis of hardened cement pastes involving ground granulated blast-furnace slag  

Microsoft Academic Search

The microstructure and composition of hardened cement pastes of a wide range of blends of ground granulated blast-furnace slag with ordinary Portland cement have been studied, using techniques of transmission electron microscopy with microanalysis combined with electron microprobe analysis. Throughout the range, a calcium silicate hydrate gel (C-S-H) is the dominant cementing phase, present in the “inner product” within the

I. G. Richardson; G. W. Groves

1992-01-01

401

Incorporation of waste materials into portland cement clinker synthesized from natural raw materials  

Microsoft Academic Search

For every ton of portland cement that is manufactured, approximately half a ton of carbon dioxide is released from calcining\\u000a limestone. One method of reducing the carbon dioxide from portland cement production is to reduce or eliminate the use of\\u000a limestone through replacement with calcium oxide-bearing waste materials. In this study, portland cement clinker was synthesized\\u000a using minimal limestone content

Irvin A. Chen; Maria C. G. Juenger

2009-01-01

402

Wear of acrylic cement (methylene-polymethacrylate) can manifest as extraosseous cement granuloma or false aneurysm of the popliteal artery after total knee arthroplasty.  

PubMed

Wear particles of acrylic cement, similar to other biomaterials, can cause periprosthetic osteolysis and formation of extraosseous cement granuloma (ECG). Expansive granuloma can manifest as a tumorous mass adjacent to the knee prosthesis, or it even can damage the popliteal artery and lead to false aneurysm formation. Suspicion of these two conditions requires a complex diagnostic approach and eventually revision of the endoprosthesis itself or reparation of the popliteal artery. Despite the beneficial fixative properties of acrylic cement (methylene-polymethacrylate), which are important for implantation of joint prostheses, the acrylic cement can also cause severe complications related to the wear process. PMID:25272212

Babiak, Ireneusz

2014-01-01

403

High Yield Production Process for Shigella Outer Membrane Particles  

PubMed Central

Gram-negative bacteria naturally shed particles that consist of outer membrane lipids, outer membrane proteins, and soluble periplasmic components. These particles have been proposed for use as vaccines but the yield has been problematic. We developed a high yielding production process of genetically derived outer membrane particles from the human pathogen Shigella sonnei. Yields of approximately 100 milligrams of membrane-associated proteins per liter of fermentation were obtained from cultures of S. sonnei ?tolR ?galU at optical densities of 30–45 in a 5 L fermenter. Proteomic analysis of the purified particles showed the preparation to primarily contain predicted outer membrane and periplasmic proteins. These were highly immunogenic in mice. The production of these outer membrane particles from high density cultivation of bacteria supports the feasibility of scaling up this approach as an affordable manufacturing process. Furthermore, we demonstrate the feasibility of using this process with other genetic manipulations e.g. abolition of O antigen synthesis and modification of the lipopolysaccharide structure in order to modify the immunogenicity or reactogenicity of the particles. This work provides the basis for a large scale manufacturing process of Generalized Modules of Membrane Antigens (GMMA) for production of vaccines from Gram-negative bacteria. PMID:22701551

Berlanda Scorza, Francesco; Colucci, Anna Maria; Maggiore, Luana; Sanzone, Silvia; Rossi, Omar; Ferlenghi, Ilaria; Pesce, Isabella; Caboni, Mariaelena; Norais, Nathalie; Di Cioccio, Vito; Saul, Allan; Gerke, Christiane

2012-01-01

404

Production of stable isotopes utilizing the plasma separation process  

NASA Astrophysics Data System (ADS)

A plasma separation process (PSP) is being operated at Theragenics Corporation's ®, Oak Ridge, TN, facility for the enrichment of stable isotopes. The PSP utilizes ion cyclotron mass discrimination to separate isotopes on a relatively large scale. With a few exceptions, nearly any metallic element could be processed with PSP. Output isotope enrichment factor depends on natural abundance and mass separation and can be fairly high in some cases. The Theragenics™ PSP facility is believed to be the only such process currently in operation. This system was developed and formerly operated under the US Department of Energy Advanced Isotope Separation program. Theragenics™ also has a laboratory at the PSP site capable of harvesting the isotopes from the process and a mass spectrometer system for analyzing enrichment and product purity. Since becoming operational in 2002, Theragenics™ has utilized the PSP to separate isotopes of several elements including: dysprosium, erbium, gadolinium, molybdenum and nickel. Currently, Theragenics™ is using the PSP for the separation of 102Pd, which is used as precursor for the production of 103Pd. The 103Pd radioisotope is the active ingredient in TheraSeed ®, which is used in the treatment of early stage prostate cancer and being investigated for other medical applications. New industrial, medical and research applications are being investigated for isotopes that can be enriched on the PSP. Pre-enrichment of accelerator or reactor targets offers improved radioisotope production. Theragenics operates 14 cyclotrons for proton activation and has access to HFIR at ORNL for neutron activation of radioisotopes.

Bigelow, T. S.; Tarallo, F. J.; Stevenson, N. R.

2005-12-01

405

Mapping Asbestos-Cement Roofing with Hyperspectral Remote Sensing over a Large Mountain Region of the Italian Western Alps  

PubMed Central

The World Health Organization estimates that 100 thousand people in the world die every year from asbestos-related cancers and more than 300 thousand European citizens are expected to die from asbestos-related mesothelioma by 2030. Both the European and the Italian legislations have banned the manufacture, importation, processing and distribution in commerce of asbestos-containing products and have recommended action plans for the safe removal of asbestos from public and private buildings. This paper describes the quantitative mapping of asbestos-cement covers over a large mountainous region of Italian Western Alps using the Multispectral Infrared and Visible Imaging Spectrometer sensor. A very large data set made up of 61 airborne transect strips covering 3263 km2 were processed to support the identification of buildings with asbestos-cement roofing, promoted by the Valle d'Aosta Autonomous Region with the support of the Regional Environmental Protection Agency. Results showed an overall mapping accuracy of 80%, in terms of asbestos-cement surface detected. The influence of topography on the classification's accuracy suggested that even in high relief landscapes, the spatial resolution of data is the major source of errors and the smaller asbestos-cement covers were not detected or misclassified. PMID:25166502

Frassy, Federico; Candiani, Gabriele; Rusmini, Marco; Maianti, Pieralberto; Marchesi, Andrea; Nodari, Francesco Rota; Via, Giorgio Dalla; Albonico, Carlo; Gianinetto, Marco

2014-01-01

406

Product and Process Improvement Using Mixture-Process Variable Designs and Robust Optimization Techniques  

SciTech Connect

The quality of an industrial product depends on the raw material proportions and the process variable levels, both of which need to be taken into account in designing a product. This article presents a case study from the food industry in which both kinds of variables were studied by combining a constrained mixture experiment design and a central composite process variable design. Based on the natural structure of the situation, a split-plot experiment was designed and models involving the raw material proportions and process variable levels (separately and combined) were fitted. Combined models were used to study: (i) the robustness of the process to variations in raw material proportions, and (ii) the robustness of the raw material recipes with respect to fluctuations in the process variable levels. Further, the expected variability in the robust settings was studied using the bootstrap.

Sahni, Narinder S.; Piepel, Gregory F.; Naes, Tormod

2009-04-01

407

Oxygen production processes on the Moon: An overview  

NASA Technical Reports Server (NTRS)

The production of oxygen on the Moon utilizing indigenous material is paramount to a successful lunar colonization. Several processes were put forth to accomplish this. The lunar liquid oxygen (LLOX) generation schemes which have received the most study to date are those involving: (1) the reduction of ilmenite (FeTiO3) by H2, C, CO, CH4, CO-Cl2 plasma; (2) magma electrolysis, both unadulterated and fluoride-fluxed, and (3) several others, including carbo-chlorination, HF acid leaching, fluorine extraction, magma oxidation, and vapor pyrolysis. The H2 reduction of ilmenite and magma electrolysis processes have received the most study to date. At this stage of development, they both appear feasible schemes with various pros and cons. However, all processes should be addressed at least at the onset of the considerations. It is ultimatley the energy requirements of the entire process, including the acquisition of feedstock, which will determine the mode of oxygen productions. There is an obvious need for considerably more experimentation and study. Some of these requisite studies are in progress, and several of the most studied and feasible processes for winning oxygen from lunar materials are reviewed.

Taylor, Lawrence A.; Carrier, W. David, III

1991-01-01

408

Solder extrusion pressure bonding process and bonded products produced thereby  

DOEpatents

Disclosed is a process for production of soldered joints which are highly reliable and capable of surviving 10,000 thermal cycles between about [minus]40 C and 110 C. Process involves interposing a thin layer of a metal solder composition between the metal surfaces of members to be bonded and applying heat and up to about 1000 psi compression pressure to the superposed members, in the presence of a reducing atmosphere, to extrude the major amount of the solder composition, contaminants including fluxing gases and air, from between the members being bonded, to form a very thin, strong intermetallic bonding layer having a thermal expansion tolerant with that of the bonded members.

Beavis, L.C.; Karnowsky, M.M.; Yost, F.G.

1992-06-16

409

Process for production of an ether-rich additive  

SciTech Connect

A process is described for the production of tertiary amyl methyl ether (TAME) comprising: (a) providing a liquid hydrocarbon C[sub 4] - C[sub 12] feedstock containing nitriles and isoamylenes; (b) admixing said liquid hydrocarbon C[sub 4] - C[sub 12] feedstock with an alcohol selected from the group consisting of methanol, ethanol, propanol and mixtures thereof to form a mixture of hydrocarbon feedstock and alcohol; (c) distilling said mixture of hydrocarbon feedstock and alcohol under controlled conditions so as to obtain a product comprising a C[sub 5] hydrocarbon-alcohol azeotrope feedstock rich in C[sub 5] and substantially free of nitriles; and (d) contacting said C[sub 5] hydrocarbon-alcohol azeotrope with a catalyst under etherification process conditions to produce tertiary amyl methyl ether (TAME).

Marquez, M.A.; Gonzalez, J.C.

1993-08-24

410

Uses of by-product lignins from alcohol fuel processes  

SciTech Connect

The large-scale conversion of biomass to alcohol fuels generates substantial quantities by-product lignins. The form and structure of these lignins depends upon the source of the biomass, the conversion process, and the conditions of operation. A high by-product credit for these biomass lignins significantly enhances the economics of alcohol fuels processes. The existing and potential markets for lignins can be classified into polymers, modified polymers, prepolymers, and low-molecular-weight chemicals, and fuels. Two promising large-volume applications for lignins are plywood and particle-board adhesives ad extenders for asphalt in pavement mixtures. Results of research on lignin-based adhesives and asphalts will be reported. In the case of asphalt, up to 40% of the asphalt content of mixes could be replaced by lignin without loss of stability. 8 figures, 1 table.

Sundstrom, D.W.; Klei, H.E.

1982-01-01

411

The Fractal Ratio as a Metric of Nanostructure Development in Hydrating Cement Paste  

NASA Astrophysics Data System (ADS)

It is necessary to have appropriate metrics to quantify the development of the nanostructure in Portland cement paste. The fractal ratio, calculated from Small Angle Neutron Scattering (SANS) data, serves as such a metric. It expresses the proportion of the volume-fractal surface area of calcium-silicate-hydrate gel (C-S-H) to the surface-fractal surface area. The volume fractal develops in the scale range from ? 5 nm to ? 100 nm, and it is associated with the formation of outer product in the capillary pore space by the through-solution mechanism. The surface fractal is attributed to the surface structure formed by colloidal particles on solid substrates such as the Portland cement grains and fly ash particles. The evolution of this ratio over time provides insight into which types of hydration processes are dominant. Applied to study of the hydration of fly ash/Portland cement mixes at later ages, the fractal ratio method showed that in every case, except two, there was a reduced hydration rate due to the dilution effect. The two exceptions involved fly ash fractions with sufficient CaO to generate significant C-S-H gel by the alkali-activated reaction. In all cases the fractal ratio increased with time, indicating the production of additional C-S-H through the topochemical reaction.

Livingston, R. A.; Bumrongjaroen, W.; Allen, A. J.

412

A recyclable enzymatic biodiesel production process in ionic liquids.  

PubMed

Immobilized Candida antarctica lipase B suspended in ionic liquids containing long alkyl-chain cations showed excellent synthetic activity and operational stability for biodiesel production. The interest of this process lies in the possibility of recycling the biocatalyst and the easy separation of the biodiesel from the reaction mixture. The ionic liquids used, 1-hexadecyl-3-methylimidazolium triflimide ([C(16)MIM][NTf(2)]) and 1-octadecyl-3-methylimidazolium triflimide ([C(18)MIM][NTf(2)]), produced homogeneous systems at the start of the reaction and, at the end of the same, formed a three-phase system, allowing the selective extraction of the products using straightforward separation techniques, and the recycling of both the ionic liquid and the enzyme. These are very important advantages which may be found useful in environmentally friendly production conditions. PMID:21392972

De Diego, Teresa; Manjón, Arturo; Lozano, Pedro; Iborra, José L

2011-05-01

413

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

SciTech Connect

China's cement industry, which produced 1,388 million metric tons (Mt) of cement in 2008, accounts for almost half of the world's total cement production. Nearly 40% of China's cement production is from relatively obsolete vertical shaft kiln (VSK) cement plants, with the remainder from more modern rotary kiln cement plants, including plants equipped with new suspension pre-heater and pre-calciner (NSP) kilns. Shandong Province is the largest cement-producing Province in China, producing 10% of China's total cement output in 2008. This report documents an analysis of the potential to improve the energy efficiency of NSP kiln cement plants in Shandong Province. Sixteen NSP kiln cement plants were surveyed regarding their cement production, energy consumption, and current adoption of 34 energy-efficient technologies and measures. Plant energy use was compared to both domestic (Chinese) and international best practice using the Benchmarking and Energy Saving Tool for Cement (BEST-Cement). This benchmarking exercise indicated an average technical potential primary energy savings of 12% would be possible if the surveyed plants operated at domestic best practice levels in terms of energy use per ton of cement produced. Average technical potential primary energy savings of 23% would be realized if the plants operated at international best practice levels. Energy conservation supply curves for both fuel and electricity savings were then constructed for the 16 surveyed plants. Using the bottom-up electricity conservation supply curve model, the cost-effective electricity efficiency potential for the studied cement plants in 2008 is estimated to be 373 gigawatt hours (GWh), which accounts for 16% of total electricity use in the 16 surveyed cement plants in 2008. Total technical electricity-saving potential is 915 GWh, which accounts for 40% of total electricity use in the studied plants in 2008. The fuel conservation supply curve model shows the total technical fuel efficiency potential equal to 7,949 terajoules (TJ), accounting for 8% of total fuel used in the studied cement plants in 2008. All the fuel efficiency potential is shown to be cost effective. Carbon dioxide (CO{sub 2}) emission reduction potential associated with cost-effective electricity saving is 383 kiloton (kt) CO{sub 2}, while total technical potential for CO{sub 2} emission reduction from electricity-saving is 940 ktCO{sub 2}. The CO{sub 2} emission reduction potentials associated with fuel-saving potentials is 950 ktCO{sub 2}.

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

2009-10-01

414

Influence of Solids-to-liquid and Activator Ratios on Calcined Kaolin Cement Powder  

NASA Astrophysics Data System (ADS)

This paper summarizes the effect of activator ratio on the processing of cement powder. Geopolymer slurry was produced via alkaline activation of calcined kaolin. Once the geopolymer slurry solidified, it was crushed and ground to obtain cement powder. Ultilizing the concept of “just adding water”, hardened cement paste could be produced from cement powder. This paper concluded that solids-to-liquid and sodium silicate-to-sodium hydroxide ratios have a significant effect on compressive strength of hardened cement paste. The optimum solids-to-liquid and sodium silicate-to-sodium hydroxide ratios were 0.80 and 0.20, respectively. SEM micrographs showed that a processing route to produce cement powder by “just adding water” was possible, and the structure became denser and fewer unreacted particles were observed.

Liew, Y. M.; Kamarudin, H.; Bakri, A. M. Mustafa Al; Binhussain, M.; Luqman, M.; Nizar, I. Khairul; Ruzaidi, C. M.; Heah, C. Y.

415

Separation of products from mild coal gasification processes  

SciTech Connect

The primary mild coal gasification product mixture containing noncondensible gas, high-boiling hydrocarbon vapors and entrained fines is difficult to process into the desired pure products: gas, liquids, and dry solids. This challenge for mild coal gasification process development has been studied by surveying the technical literature for suitable separations processes and for similar issues in related processes. The choice for a first-stage solids separation step is standard cyclones, arranged in parallel trains for large-volume applications in order to take advantage of the higher separation efficiency of smaller cyclones. However, mild gasification pilot-plant data show entrainment of ultrafine particles for which standard cyclones have poor separation efficiency. A hot secondary solids separation step is needed for the ultrafine entrainment in order to protect the liquid product from excessive amounts of contaminating solids. The secondary solids separation step is similar to many high-temperature flue-gas applications with an important complicating condition: Mild gasifier vapors form coke on surfaces in contact with the vapors. Plugging of the filter medium by coke deposition is concluded to be the main product separation problem for mild gasification. Three approaches to solution of this problem are discussed in the order of preference: (1) a barrier filter medium made of a perforated foil that is easy to regenerate, (2) a high-efficiency cyclone coupled with recycle of a solids-containing tar fraction for coking/cracking in the gasifier, and (3) a granular moving bed filter with regeneration of the bed material. The condensation of oil vapors diluted by noncondensible gas is analyzed thermodynamically, and the conclusion is that existing commercial oil fractionator designs are adequate as long as the vapor stream does not contain excessive amounts of solids. 34 refs., 4 figs.

Wallman, P.H.

1991-09-11

416

U-GAS process for production of hydrogen from coal  

Microsoft Academic Search

Today, hydrogen is produced mainly from natural gas and petroleum fractions. Tomorrow, because reserves of natural gas and oil are declining while demand continues to increase, they cannot be considered available for long-term, large-scale production of hydrogen. Hydrogen obtained from coal is expected to be the lowest cost, large-scale source of hydrogen in the future. The U-GAS coal gasification process

R. J. Dihu; J. G. Patel

1982-01-01

417

Micrometer-scale 3-D shape characterization of eight cements: Particle shape and cement chemistry, and the effect of particle shape on laser diffraction particle size measurement  

SciTech Connect

Eight different portland cements were imaged on a synchrotron beam line at Brookhaven National Laboratory using X-ray microcomputed tomography at a voxel size of about 1 mum per cubic voxel edge. The particles ranged in size roughly between 10 mum and 100 mum. The shape and size of individual particles were computationally analyzed using spherical harmonic analysis. The particle shape difference between cements was small but significant, as judged by several different quantitative shape measures, including the particle length, width, and thickness distributions. It was found that the average shape of cement particles was closely correlated with the volume fraction of C{sub 3}S (alite) and C{sub 2}S (belite) making up the cement powder. It is shown that the non-spherical particle shape of the cements strongly influence laser diffraction results, at least in the sieve size range of 20 mum to 38 mum. Since laser diffraction particle size measurement is being increasingly used by the cement industry, while cement chemistry is always a main factor in cement production, these results could have important implications for how this kind of particle size measurement should be understood and used in the cement industry.

Erdogan, S.T. [Middle East Technical University, Dept. of Civil Engineering, Ankara 06531 (Turkey); Nie, X. [Johns Hopkins University, Department of Physics, Baltimore, Maryland (United States); Stutzman, P.E. [Inorganic Materials Group, Materials and Construction Research Division, Building and Fire Research Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland (United States); Garboczi, E.J., E-mail: edward.garboczi@nist.go [Inorganic Materials Group, Materials and Construction Research Division, Building and Fire Research Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland (United States)

2010-05-15

418

SENTINEL-2 Level 1 Products and Image Processing Performances  

NASA Astrophysics Data System (ADS)

In partnership with the European Commission and in the frame of the Global Monitoring for Environment and Security (GMES) program, the European Space Agency (ESA) is developing the Sentinel-2 optical imaging mission devoted to the operational monitoring of land and coastal areas. The Sentinel-2 mission is based on a satellites constellation deployed in polar sun-synchronous orbit. While ensuring data continuity of former SPOT and LANDSAT multi-spectral missions, Sentinel-2 will also offer wide improvements such as a unique combination of global coverage with a wide field of view (290 km), a high revisit (5 days with two satellites), a high resolution (10 m, 20 m and 60 m) and multi-spectral imagery (13 spectral bands in visible and shortwave infra-red domains). In this context, the Centre National d'Etudes Spatiales (CNES) supports ESA to define the system image products and to prototype the relevant image processing techniques. This paper offers, first, an overview of the Sentinel-2 system and then, introduces the image products delivered by the ground processing: the Level-0 and Level-1A are system products which correspond to respectively raw compressed and uncompressed data (limited to internal calibration purposes), the Level-1B is the first public product: it comprises radiometric corrections (dark signal, pixels response non uniformity, crosstalk, defective pixels, restoration, and binning for 60 m bands); and an enhanced physical geometric model appended to the product but not applied, the Level-1C provides ortho-rectified top of atmosphere reflectance with a sub-pixel multi-spectral and multi-date registration; a cloud and land/water mask is associated to the product. Note that the cloud mask also provides an indication about cirrus. The ground sampling distance of Level-1C product will be 10 m, 20 m or 60 m according to the band. The final Level-1C product is tiled following a pre-defined grid of 100x100 km2, based on UTM/WGS84 reference frame. The stringent image quality requirements are also described, in particular the geo-location accuracy for both absolute (better than 12.5 m) and multi-temporal (better than 0.3 pixels) cases. Then, the prototyped image processing techniques (both radiometric and geometric) will be addressed. The radiometric corrections will be first introduced. They consist mainly in dark signal and detector relative sensitivity correction, crosstalk correction and MTF restoration. Then, a special focus will be done on the geometric corrections. In particular the innovative method of automatic enhancement of the geometric physical model will be detailed. This method takes advantage of a Global Reference Image database, perfectly geo-referenced, to correct the physical geometric model of each image taken. The processing is based on an automatic image matching process which provides accurate ground control points between a given band of the image to refine and a reference image, allowing to dynamically calibrate the viewing model. The generation of the Global Reference Image database made of Sentinel-2 pre-calibrated mono-spectral images will be also addressed. In order to perform independent validation of the prototyping activity, an image simulator dedicated to Sentinel-2 has been set up. Thanks to this, a set of images have been simulated from various source images and combining different acquisition conditions and landscapes (mountains, deserts, cities …). Given disturbances have been also simulated so as to estimate the end to end performance of the processing chain. Finally, the radiometric and geometric performances obtained by the prototype will be presented. In particular, the geo-location performance of the level-1C products which widely fulfils the image quality requirements will be provided.

Baillarin, S. J.; Meygret, A.; Dechoz, C.; Petrucci, B.; Lacherade, S.; Tremas, T.; Isola, C.; Martimort, P.; Spoto, F.

2012-07-01

419

Chemical structure of cement aged at normal and elevated temperatures and pressures, Part II: Low permeability class G oilwell cement  

SciTech Connect

Recently, Low Permeability Cement formulation has been developed for oilwell cementing. Therefore, it is important to understand the physical and chemical processes causing cement degradation in the downhole environment. In this study, we have characterised a Low Permeability Class G oilwell Cement immersed for one year in brine at T = 293 K, p = 10{sup 5} Pa and T = 353 K, p = 7 x 10{sup 6} Pa using {sup 29}Si, {sup 27}Al NMR and XRD techniques. Elevated temperature and pressure conditions increase the rate of the pozzolanic reaction and have significant effects on the polymerisation of C-S-H and on the incorporation of Al in the C-S-H structure. Leaching resulted in the formation of calcite and a more polymerised C-S-H with the appearance of tobermorite in the sample cured at elevated temperature and pressure.

Le Saout, Gwenn [Institut Francais du Petrole, 1-4 av de Bois Preau, 92852 Rueil-Malmaison (France) and Laboratoire de Physique et Mecanique des Milieux Heterogenes UMR CNRS 7636, Ecole Superieure de Physique et Chimie Industrielles, 10 rue Vauquelin, 75231 Paris Cedex 05 (France)]. E-mail: gwenn.lesaout@epfl.ch; Lecolier, Eric [Institut Francais du Petrole, 1-4 av de Bois Preau, 92852 Rueil-Malmaison (France); Rivereau, Alain [Institut Francais du Petrole, 1-4 av de Bois Preau, 92852 Rueil-Malmaison (France); Zanni, Helene [Laboratoire de Physique et Mecanique des Milieux Heterogenes UMR CNRS 7636, Ecole Superieure de Physique et Chimie Industrielles, 10 rue Vauquelin, 75231 Paris Cedex 05 (France)

2006-03-15

420

Process for Low Cost Domestic Production of LIB Cathode Materials  

SciTech Connect

The objective of the research was to determine the best low cost method for the large scale production of the Nickel-Cobalt-Manganese (NCM) layered cathode materials. The research and development focused on scaling up the licensed technology from Argonne National Laboratory in BASF’s battery material pilot plant in Beachwood Ohio. Since BASF did not have experience with the large scale production of the NCM cathode materials there was a significant amount of development that was needed to support BASF’s already existing research program. During the three year period BASF was able to develop and validate production processes for the NCM 111, 523 and 424 materials as well as begin development of the High Energy NCM. BASF also used this time period to provide free cathode material samples to numerous manufactures, OEM’s and research companies in order to validate the ma-terials. The success of the project can be demonstrated by the construction of the production plant in Elyria Ohio and the successful operation of that facility. The benefit of the project to the public will begin to be apparent as soon as material from the production plant is being used in electric vehicles.

Thurston, Anthony

2012-10-31

421

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

Microsoft Academic Search

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

Q. Y. Chen; M. Tyrer; C. D. Hills; X. M. Yang; P. Carey

2009-01-01

422

Reducing the potential for processing contaminant formation in cereal products  

PubMed Central

Processing contaminants may be defined as substances that are produced in a food when it is cooked or processed, are not present or are present at much lower concentrations in the raw, unprocessed food, and are undesirable either because they have an adverse effect on product quality or because they are potentially harmful. The presence of very low levels of processing contaminants in common foods is becoming an increasingly important issue for the food industry, as developments in analytical techniques and equipment bring foods under closer and closer scrutiny. This review considers the formation of lipid oxidation products, hydrogenation of polyunsaturated fatty acids to prevent lipid oxidation and the associated risk of trans fatty acid formation. The formation of acrylamide in the Maillard reaction is described, as well as the genetic and agronomic approaches being taken to reduce the acrylamide-forming potential of cereal grain. The multiple routes for the formation of furan and associated chemicals, including hydroxymethylfurfuryl, are also described. The evolving regulatory and public perception situations for these processing contaminants and their implications for the cereal supply chain are discussed, emphasising the need for cereal breeders to engage with the contaminants issue. PMID:24882936

Curtis, Tanya Y.; Postles, Jennifer; Halford, Nigel G.

2014-01-01

423

Continuous learning process in new product development in the Thai food-processing industry  

Microsoft Academic Search

New product development (NPD) in food-processing industries is often one element which determines whether companies are able to remain competitive in rapidly changing consumer markets. Current research suggests that well-managed NPD should be organized as a continuous learning process. It should have strong information linkage across functions and outside the company to suppliers and customers. We examine NPD in Thailand’s

Prisana Suwannaporn; Mark Speece

2000-01-01

424

Similarities and differences of microstructure and macro properties between portland and blended cement  

SciTech Connect

The relationship between microstructure and macro properties of different cementitious materials has been investigated. This study consists of the following tasks: using NMR and IR to better characterize the amorphous and poorly crystalline phases that occur in blended cements; characterizing the microstructure of the hydration products of modified Portland cement as a function of different percentages of pozzolan replacements by ESEM, SEM, and EDS; comparing the properties of blended cement pastes with a control group of normal Portland cements; and studying the engineering aspects of blended cement that are important for identifying and characterizing fundamental phenomena that are responsible for their durability. The overall influence of the nanoscale and microscale structure of blended and Portland cement on the properties of the resultant composite will be discussed.

Jiang, W.; Silsbee, M.R.; Roy, D.M. [Pennsylvania State Univ., University Park, PA (United States). Intercollege Materials Research Lab.] [Pennsylvania State Univ., University Park, PA (United States). Intercollege Materials Research Lab.

1997-10-01

425

Experimental Investigation of Concrete with Combined High alumina cement, Silica fume and M-Sand  

NASA Astrophysics Data System (ADS)

Concrete is by far the most widely used construction material today. It is estimated that present consumption of concrete in the world is of the order of 10 billion tonnes every year. The cement industry is responsible for about 6% of all CO2 emissions. So nowadays there is a great interest in the development and implementation of various alternatives to Portland cement as a binder in concrete and also alternatives to fine and coarse aggregates in concrete to reduce the energy used in production of Portland cement clinker and the associated greenhouse gas emission and also for reducing resources consumption by proper recycling. This research work is carried out in order to explore the effect of various replacement percentages of cement by combined High alumina cement with silica fume and also the fine aggregate is fully replaced with manufacturing sand. Conclusion is made based on the comparison between the performance of blended cement concrete and conventional concrete.

Joseph, Dona Maria; Devi, Manjula; Senthilkumar, S.

2013-03-01

426

Semisolid Metal Processing Techniques for Nondendritic Feedstock Production  

PubMed Central

Semisolid metal (SSM) processing or thixoforming is widely known as a technology that involves the formation of metal alloys between solidus and liquidus temperatures. For the procedure to operate successfully, the microstructure of the starting material must consist of solid near-globular grains surrounded by a liquid matrix and a wide solidus-to-liquidus transition area. Currently, this process is industrially successful, generating a variety of products with high quality parts in various industrial sectors. Throughout the years since its inception, a number of technologies to produce the appropriate globular microstructure have been developed and applied worldwide. The main aim of this paper is to classify the presently available SSM technologies and present a comprehensive review of the potential mechanisms that lead to microstructural alterations during the preparation of feedstock materials for SSM processing. PMID:24194689

Mohammed, M. N.; Omar, M. Z.; Salleh, M. S.; Alhawari, K. S.; Kapranos, P.

2013-01-01

427

Product-oriented Software Certification Process for Software Synthesis  

NASA Technical Reports Server (NTRS)

The purpose of this document is to propose a product-oriented software certification process to facilitate use of software synthesis and formal methods. Why is such a process needed? Currently, software is tested until deemed bug-free rather than proving that certain software properties exist. This approach has worked well in most cases, but unfortunately, deaths still occur due to software failure. Using formal methods (techniques from logic and discrete mathematics like set theory, automata theory and formal logic as opposed to continuous mathematics like calculus) and software synthesis, it is possible to reduce this risk by proving certain software properties. Additionally, software synthesis makes it possible to automate some phases of the traditional software development life cycle resulting in a more streamlined and accurate development process.

Nelson, Stacy; Fischer, Bernd; Denney, Ewen; Schumann, Johann; Richardson, Julian; Oh, Phil

2004-01-01

428

Application of Thermoporometry to Evaluate the Mesoporosity of Cement Pastes  

NASA Astrophysics Data System (ADS)

In the context of temporary near-surface or reversible deep geological storage of intermediate-level radioactive waste (ILW), most wastes package concepts comprise an external container made of fiber reinforced concrete, receiving several primary waste packages. Self-irradiation of encapsulating and/or embedding matrices can lead to continuous production of hydrogen which, for obvious safety reasons, must be removed from the container. Previous studies have demonstrated that gas transport depends on two interdependent factors: the water saturation and the microstructural properties of the material. Most techniques used to investigate cement paste porosity require drying of the cement paste prior to the test, which can modify the material microstructure and does not permit the localization of the aqueous phase in the material with various degrees of saturations. This paper focuses on the characterization of pores in cement paste by thermoporometry. The technique, based on the thermodynamic conditions of the melting-solidification reactions of a condensate inside a porous body, provides a simple method for determining the pore size distribution in saturated cement pastes. The results obtained on cement pastes of different formulations with different types of cement are discussed in term of material microstructure and compared with those obtained by other techniques.

Vu, T.-H.; Frizon, F.; Lorente, S.

2010-05-01

429

An assessment of gas-side fouling in cement plants  

NASA Technical Reports Server (NTRS)

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

Marner, W. J.

1982-01-01

430

Innovative Fresh Water Production Process for Fossil Fuel Plants  

SciTech Connect

This project concerns a diffusion driven desalination (DDD) process where warm water is evaporated into a low humidity air stream, and the vapor is condensed out to produce distilled water. Although the process has a low fresh water to feed water conversion efficiency, it has been demonstrated that this process can potentially produce low cost distilled water when driven by low grade waste heat. This report describes the annual progress made in the development and analysis of a Diffusion Driven Desalination (DDD) system. A dynamic analysis of heat and mass transfer demonstrates that the DDD process can yield a fresh water production of 1.03 million gallon/day by utilizing waste heat from a 100 MW steam power plant based on a condensing steam pressure of only 3 Hg. The optimum operating condition for the DDD process with a high temperature of 50 C and sink temperature of 25 C has an air mass flux of 1.5 kg/m{sup 2}-s, air to feed water mass flow ratio of 1 in the diffusion tower, and a fresh water to air mass flow ratio of 2 in the condenser. Operating at these conditions yields a fresh water production efficiency (m{sub fW}/m{sub L}) of 0.031 and electric energy consumption rate of 0.0023 kW-hr/kg{sub fW}. Throughout the past year, the main focus of the desalination process has been on the direct contact condenser. Detailed heat and mass transfer analyses required to size and analyze these heat and mass transfer devices are described. The analyses agree quite well with the current data. Recently, it has been recognized that the fresh water production efficiency can be significantly enhanced with air heating. This type of configuration is well suited for power plants utilizing air-cooled condensers. The experimental DDD facility has been modified with an air heating section, and temperature and humidity data have been collected over a range of flow and thermal conditions. It has been experimentally observed that the fresh water production rate is enhanced when air is heated prior to entering the diffusion tower. Further analytical analysis is required to predict the thermal and mass transport with the air heating configuration.

James F. Klausner; Renwei Mei; Yi Li; Jessica Knight; Venugopal Jogi

2005-09-01

431

Evidences of chemical interaction between EVA and hydrating Portland cement  

Microsoft Academic Search

In spite of the widespread use of ethylene\\/vinyl acetate copolymer (EVA) in mortar and concrete production, there is no agreement among various researchers about the kind of interaction that is developed between cement and polymeric phases. Therefore, the adoption of adequate measures for final product quality achievement is impaired, as well as the adjustment of their properties to the desired

D. A. Silva; H. R. Roman; P. J. P. Gleize

2002-01-01

432

Nisin Production Utilizing Skimmed Milk Aiming to Reduce Process Cost  

NASA Astrophysics Data System (ADS)

Nisin is a natural additive for conservation of food, pharmaceutical, and dental products and can be used as a therapeutic agent. Nisin inhibits the outgrowth of spores, the growth of a variety of Gram-positive and Gram-negative bacteria. This study was performed to optimize large-scale nisin production in skimmed milk and subproducts aiming at low-costs process and stimulating its utilization. Lactococcus lactis American Type Culture Collection (ATCC) 11454 was developed in a rotary shaker (30°C/36 h/100 rpm) in diluted skimmed milk and nisin activity, growth parameters, and media components were also studied. Nisin activity in growth media was expressed in arbitrary units (AU/mL) and converted to standard nisin concentration (Nisaplin®, 25 mg of pure nisin is 1.0×106 AU/mL). Nisin activity in skimmed milk 2.27 gtotal solids was up to threefold higher than transfers in skimmed milk 4.54 gtotal solids and was up to 85-fold higher than transfers in skimmed milk 1.14 gtotal solids. L. lactis was assayed in a New Brunswick fermentor with 1.5 L of diluted skimmed milk (2.27 gtotal solids) and airflow of 1.5 mL/min (30°C/36/200 rpm), without pH control. In this condition nisin activity was observed after 4 h (45.07 AU/mL) and in the end of 36 h process (3312.07 AU/mL). This work shows the utilization of a low-cost growth medium (diluted skimmed milk) to nisin production with wide applications. Furthermore, milk subproducts (milk whey) can be exploited in nisin production, because in Brazil 50% of milk whey is disposed with no treatment in rivers and because of high organic matter concentrations it is considered an important pollutant. In this particular case an optimized production of an antimicrobial would be lined up with industrial disposal recycling.

Jozala, Angela Faustino; de Andrade, Maura Sayuri; de Arauz, Luciana Juncioni; Pessoa, Adalberto; Penna, Thereza Christina Vessoni

433

Engineering Management Model for the early stage of Conceptual Design for the Product Innovation Process  

Microsoft Academic Search

The product concept phase of the product innovation process is a creative and interdisciplinary activity that transforms a market opportunity and technological innovation into successful products. It is a set of activity based processes in a product-oriented enterprise, and is essential to the economics success of such organization. Well-designed processes reduce development time, create better products, generate profit, and increase

N. Jamali; ETH Zürich; M. Meier

434

Biological Production in Lakes. Physical Processes in Terrestrial and Aquatic Ecosystems, Ecological Processes.  

ERIC Educational Resources Information Center

These materials were designed to be used by life science students for instruction in the application of physical theory to ecosystem operation. Most modules contain computer programs which are built around a particular application of a physical process. Primary production in aquatic ecosystems is carried out by phytoplankton, microscopic plants…

Walters, R. A.; Carey, G. F.

435

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

NASA Astrophysics Data System (ADS)

The characteristics of cement kiln dusts (CKDs) and their effects as partial replacement of Portland Cement (PC) were studied in this research program. The cement industry is currently under pressure to reduce greenhouse gas (GHG) emissions and solid by-products in the form of CKDs. The use of CKDs in concrete has the potential to substantially reduce the environmental impact of their disposal and create significant cost and energy savings to the cement industry. Studies have shown that CKDs can be used as a partial substitute of PC in a range of 5--15%, by mass. Although the use of CKDs is promising, there is very little understanding of their effects in CKD-PC blends. Previous studies provide variable and often conflicting results. The reasons for the inconsistent results are not obvious due to a lack of material characterization data. The characteristics of a CKD must be well-defined in order to understand its potential impact in concrete. The materials used in this study were two different types of PC (normal and moderate sulfate resistant) and seven CKDs. The CKDs used in this study were selected to provide a representation of those available in North America from the three major types of cement manufacturing processes: wet, long-dry, and preheater/precalciner. The CKDs have a wide range of chemical and physical composition based on different raw material sources and technologies. Two fillers (limestone powder and quartz powder) were also used to compare their effects to that of CKDs at an equivalent replacement of PC. The first objective of this study was to conduct a comprehensive composition analysis of CKDs and compare their characteristics to PC. CKDs are unique materials that must be analyzed differently from PC for accurate chemical and physical analysis. The present study identifies the chemical and physical analytical methods that should be used for CKDs. The study also introduced a method to quantify the relative abundance of the different mineralogical phases within CKDs. It was found that CKDs can contain significant amounts of amorphous material (>30%) and clinker compounds (>20%) and small amounts of slag and/or flyash (<5%) and calcium langbeinite (<5%). The dissolution of ionic species and composition of the liquid phase play an important role in PC hydration. The dissolved ion contributions from CKDs were compared to PC using dilute stirred suspensions at 10 minutes and it was found that the ion contributions from CKDs are qualitatively the same as the ion contributions from PC, with the exception of chloride ions. The second objective was to utilize the material characterization analysis to determine the relationships among the composition properties of CKD-PC blends and their effects on fresh and hardened properties. The study found that CKDs from preheater/precalciner kilns have different effects on workability and heat evolution than CKDs from wet and long-dry kilns due to the presence of very reactive and high free lime contents (>20%). The blends with the two CKDs from preheater/precalciner plants had higher paste water demand, lower mortar flows, and higher heat generation during initial hydrolysis in comparison to all other CKD-PC blends and control cements. The hardened properties of CKD as a partial substitute of PC appear to be governed by the sulfate content of the CKD-PC blend (the form of the CKD sulfate is not significant). According to analysis of the ASTM expansion in limewater test results, the CKD-PC blend sulfate content should be less than ˜0.40% above the optimum sulfate content of the PC. It was also found that the sulfate contribution of CKD behaves similar to gypsum. Therefore, CKD-PC blends could be optimized for sulfate content by using CKD as a partial substitute of gypsum during the grinding process to control the early hydration of C3A. The wet and long-dry kiln CKDs contain significant amounts of calcium carbonate (>20%) which could also be used as partial replacement of limestone filler in PC.

Khanna, Om Shervan

436

[Bone cements based on polymethylmethacrylate].  

PubMed

Bone cements based on polymethylmethacrylate (PMMA) remain an important material for anchorage of artificial joints. Polymers based on PMMA originally developed for dental surgery have been successfully used in bone surgery for more than 40 years. At first sight the cold-curing PMMA bone cement seems to be a rather simple material consisting of a powder and a liquid. But in fact it is a complex material fulfilling various functions at its application site after the implantation. Its properties vary according to the composition of its basic elements. They already play a decisive role for the working behavior during mixing of both components. The differences in the working behavior considerably affect the cementing technique and the accurate application in vivo. These influence the mechanical performance of the cured cement mantle and the long-term results of the implantation. Standardized test methods are used to characterize bone cements,whereas the clinical relevance of the test methods has to be evaluated critically.Additionally,PMMA bone cements act as a drug delivery system as a local carrier of antibiotics. This paper gives a review of the composition and properties of PMMA bone cements and their influence on practical application. PMID:12557085

Breusch, S J; Kühn, K-D

2003-01-01

437

Development of an industrializable fermentation process for propionic acid production.  

PubMed

Propionic acid (PA) is a short-chain fatty acid with wide industrial application including uses in pharmaceuticals, herbicides, cosmetics, and food preservatives. As a three-carbon building block, PA also has potential as a precursor for high-volume commodity chemicals such as propylene. Currently, most PA is manufactured through petrochemical routes, which can be tied to increasing prices and volatility due to difficulty in demand forecasting and feedstock availability. Herein described are research advancements to develop an industrially feasible, renewable route to PA. Seventeen Propionibacterium strains were screened using glucose and sucrose as the carbon source to identify the best platform strain. Propionibacterium acidipropionici ATCC 4875 was selected as the platform strain and subsequent fermentation optimization studies were performed to maximize productivity and yield. Fermentation productivity was improved three-fold to exceed 2 g/l/h by densifying the inoculum source. Byproduct levels, particularly lactic and succinic acid, were reduced by optimizing fermentor headspace pressure and shear. Following achievement of commercially viable productivities, the lab-grade medium components were replaced with industrial counterparts to further reduce fermentation costs. A pure enzymatically treated corn mash (ECM) medium improved the apparent PA yield to 0.6 g/g (PA produced/glucose consumed), but it came at the cost of reduced productivity. Supplementation of ECM with cyanocobalamin restored productivity to near lab-grade media levels. The optimized ECM recipe achieved a productivity of 0.5 g/l/h with an apparent PA yield of 0.60 g/g corresponding to a media cost <1 USD/kg of PA. These improvements significantly narrow the gap between the fermentation and incumbent petrochemical processes, which is estimated to have a manufacturing cost of 0.82 USD/kg in 2017. PMID:24627047

Stowers, Chris C; Cox, Brad M; Rodriguez, Brandon A

2014-05-01

438

Catalytic effect of a Portland cement filler on the cure of water-compatible resorcinol phenol-formaldehyde polymer concrete  

SciTech Connect

Aggregate with a water content < 1 wt % is normally needed for the production of polymer concrete (PC). This increases the cost and complexity of the process. In this study, PC with a compressive strength of > 2000 psi (> 13.78 MPa) at age of 1 h at 24/sup 0/C was produced by mixing resorcinol phenol-formaldehyde (RPF) resin with portland cement and aggregate containing 1 to 10% water. The addition of approx. 14.7 to 17.5% type III portland cement to the PC formulation produced an acceleration in the rate of the condensation-type polymerization reaction and improved the properties of the composite. The cause of the accelerative effect was found to be the electropositive bivalent metallic ions of calcium and magnesium released from the cement grains in an aqueous medium. Conversely, the trivalent metallic ions from cement such as Al/sup 3 +/ and Fe/sup 3 +/ have no effect on the rate of polymerization of RPF resin.

Sugama, T.; Kukacka, L.E.; Horn, W.

1981-05-01

439

Development of a process for continuous creation of lean value in product development organizations  

E-print Network

Ideas and methodologies of lean product development were developed into tools and processes that help product development organizations improve their performances. The definition of waste in product development processes ...

Kato, Jin

2005-01-01

440

Crown and bridge cements: clinical applications.  

PubMed

Cement selection can be confusing because factors such as substrate, the type of restoration, and patient needs must be considered. Some substrates require additional treatment before cementation. This article describes the most commonly used traditional crown and bridge cements (GI and RMGI) used for metal and metal-ceramic restorations, and resin cements used for all-ceramic restorations. Advantages, disadvantages, indications, and contraindications of cements have been reviewed. Recommended uses of cements for metal, ceramic, and laboratory composite restorations have been presented. General guidelines for surface treatment ot silica- and zirconia-based restorations when using resin cements have been discussed. PMID:23350265

Bunek, Sabiha S; Powers, John M

2012-12-01

441

Cleaner production opportunity assessment for a milk processing facility.  

PubMed

Possible cleaner production (CP) opportunities for a milk processing facility were examined in this study. The CP concept and its key tools of implementation were used to assess the potential CP opportunities in the facility studied. The general production process and its resulting environmental loads were investigated by taking possible CP opportunities as the basis of study. The methodology developed for CP opportunity assessment in the milk processing facility covered two major steps: preparation of checklists to assist auditing and CP opportunity assessment, and implementation of the mass-balance analysis. For mass-balance analysis, measurements and experimental analysis of the mass flows were utilized to determine the inputs and outputs. Prepared checklists were utilized to determine waste reduction options that could be implemented. Selected opportunities were evaluated considering their environmental benefits and economic feasibility. The results of the study indicated that 50% of the service water used, 9.3% of the current wastewater (WW) discharge, 65.36% of the chemical use and the discharge of 181.9 kg/day of chemical oxygen demand (COD) and 20.7 kg/day of total suspended solids (TSS) could be eliminated and 19.6% of the service water used could be recycled/reused. PMID:16945474

Ozbay, A; Demirer, G N

2007-09-01

442

A Hybrid Gas Cleaning Process for Production of Ultraclean Syngas  

SciTech Connect

The overall objective of this project is to develop technologies for cleaning/conditioning IGCC generated syngas to meet contaminant tolerance limits for fuel cell and chemical production applications. The specific goals are to develop processes for (1) removal of reduced sulfur species to sub-ppm levels using a hybrid process consisting of a polymer membrane and a regenerable ZnO-coated monolith or a mixed metal oxide sorbent; (2) removal of hydrogen chloride vapors to sub-ppm levels using an inexpensive, high-surface-area material; and (3) removal of NH3 with acidic adsorbents followed by conversion of this NH3 into nitrogen and water. Existing gasification technologies can effectively and efficiently convert a wide variety of carbonaceous feedstocks (coal, petcoke, resids, biomass, etc.) into syngas, which predominantly contains carbon monoxide and hydrogen. Unfortunately, the impurities present in these carbonaceous feedstocks are converted to gaseous contaminants such as H2S, COS, HCl, NH3, alkali macromolecules and heavy metal compounds (such as Hg) during the gasification process. Removal of these contaminants using conventional processes is thermally inefficient and capital intensive. This research and development effort is focused on investigation of modular processes for removal of sulfur, chlorine, nitrogen and mercury compounds from syngas at elevated temperature and pressures at significantly lower costs than conventional technologies.

Merkel, T.C.; Turk, B.S.; Gupta, R.P.; Cicero, D.C.; Jain, S.C.

2002-09-20