Note: This page contains sample records for the topic cement production process from Science.gov.
While these samples are representative of the content of Science.gov,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of Science.gov
to obtain the most current and comprehensive results.
Last update: November 12, 2013.
1

[Release amount of heavy metals in cement product from co-processing waste in cement kiln].  

PubMed

Clinker was produced by Simulating cement calcination test, and concrete samples were also prepared according to national standard GB/T 17671-1999. Long-term cumulative release amount of heavy metals in cement product from co-processing waste in cement kiln was researched through leaching test which refers to EA NEN 7371 and EA NEN 7375, and one-dimensional diffusion model which is on the base of Fick diffusion law. The results show that availabilities of heavy metals are lower than the total amounts in concrete. The diffusion coefficients of heavy metals are different (Cr > As > Ni > Cd). During 30 years service, the cumulative release amounts of Cr, As, Ni and Cd are 4.43 mg/kg, 0.46 mg/kg, 1.50 mg/kg and 0.02 mg/kg, respectively, and the ratios of release which is the division of cumulative release amount and availability are 27.0%, 18.0%, 3.0% and 0.2%, respectively. The most important influence factor of cumulative release amount of heavy metal is the diffusion coefficient, and it is correlative to cumulative release amount. The diffusion coefficient of Cr and As should be controlled exactly in the processing of input the cement-kiln. PMID:19558131

Yang, Yu-Fei; Huang, Qi-Fei; Zhang, Xia; Yang, Yu; Wang, Qi

2009-05-15

2

Chromium behavior during cement-production processes: a clinkerization, hydration, and leaching study.  

PubMed

The behavior of chromium during the production of cement clinker, during the hydration of cement and during the leaching of cement mortars was investigated. The microstructures of clinker and mortar properties were investigated using free lime, XRD, SEM/EDS, and TG/DTA techniques. Chromium was found to be incorporated in the clinker phase. The formation of new chromium compounds such as Ca(6)Al(4)Cr(2)O(15), Ca(5)Cr(3)O(12), Ca(5)Cr(2)SiO(12), and CaCr(2)O(7), with chromium oxidation states of +3, +4.6, +5, and +6, respectively, was detected. After the hydration process, additional chromium compounds were identified in the mortar matrix, including Ca(5)(CrO(4))(3)OH, CaCrO(4)·2H(2)O, and Al(2)(OH)(4)CrO(4), with chromium oxidation states of +4.6, +6, and +6, respectively. Additionally, some species of chromium, such as Cr(3+) from Ca(6)Al(4)Cr(2)O(15) and Cr(6+) from CaCr(2)O(7), CaCrO(4)·2H(2)O, and Al(2)(OH)(4)CrO(4), were leached during leaching tests, whereas other species remained in the mortar. The concentrations of chromium that leached from the mortar following U.S. EPA Method 1311 and EA NEN 7375:2004 leaching tests were higher than limits set by the U.S. EPA and the Environment Agency of England and Wales related to hazardous waste disposal in landfills. Thus, waste containing chromium should not be allowed to mix with raw materials in the cement manufacturing process. PMID:21592657

Sinyoung, Suthatip; Songsiriritthigul, Prayoon; Asavapisit, Suwimol; Kajitvichyanukul, Puangrat

2011-04-23

3

Well cementing process  

SciTech Connect

A process is described for improved bonding in a well system between cement, and well tubular members and the formation about the well bore at a pay zone, the steps comprising: (a) displacing at turbulent flow conditions drilling fluid materials, including mud, solids and filter cake, from the annulus between the tubular members and formation by circulating therein a slug of concentrate consisting essentially of a water-free mixture of surfactant and alcohol; and (b) following the slug of concentrate with an aqueous fluid cement whereby the slug of concentrate removes displaceable drilling fluid materials from the annulus at the pay zone but leaving some residual filter cake on the formation, and the well tubular members and residual filter cake both residing in a surface water-wetted condition after passage of the slug whereby hardening of the cement produces an improved bonding to both the well tubular members and the formation at the pay zone.

Oliver, J.E. Jr.; Singer, A.M.

1983-05-13

4

[Environment load from China's cement production].  

PubMed

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

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

2006-10-01

5

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

Microsoft Academic Search

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

Steffen Weil; Stefan Hamel; Wolfgang Krumm

2006-01-01

6

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

7

Unions and Productivity in the Cement Industry.  

National Technical Information Service (NTIS)

This study examines the impact of unionization on productivity in the U.S. cement industry. The evidence suggests that unionization increases productively on the order of 6-8 percent, after controlling for changes in the capital - labor ratio, the scale o...

K. B. Clark

1978-01-01

8

Dust exposure and respiratory health effects in cement production.  

PubMed

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

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

2012-01-01

9

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

10

Process Analysis Techniques for Cement Kilns  

Microsoft Academic Search

Some useful techniques for the process analysis of cement kilns, related experience, and theoretical considerations are discussed in this paper. In the practical application of process analysis techniques¿i.e., autocorrelation, spectral density analysis, crosscorrelation, scatter diagram, and estimation of impulse response by the use of the least-square method¿the most important problem is how to treat the data prior to data analysis

Tsutomu Itoh; Hiroshi Saito; Yasuo Takumi; Takeo Shimizu

1971-01-01

11

Reuse of heavy metal-containing sludges in cement production  

Microsoft Academic Search

The feasibility of the replacement of raw material for cement production by heavy metal-containing sludge from surface finishing and electroplating industries was investigated. The effect of heavy metal content in the cement raw mix on the crystalline formation in cement production was also examined by XRD analyses. It was found that both sludges were applicable for the replacement of raw

Pai-Haung Shih; Juu-En Chang; Hsing-Cheng Lu; Li-Choung Chiang

2005-01-01

12

Principles of technological design of wasteless chemical processes based on the use of wastes for production of alkaline slag cements and concretes  

Microsoft Academic Search

The strength characteristics of alkaline slag-cement made with the use of waste from alkaline sealing of metals are presented. The cement was prepared from granulated blast-furnance slag with average component contents in the following ranges (mass %): SiOâ 36.0-40.2, AlâOâ 4-18.2, FeO 0.1-3.7, MnO 0.4-5.2, CaO 33.1-48.8, MgO 2.2-9.8. With the use of wastes from the descaling process in alkali

V. D. Glukhovskii; I. P. Chernobaev; B. M. Emelyanov; A. P. Semenyuk

1985-01-01

13

Sustainable cement production-present and future  

SciTech Connect

Cement will remain the key material to satisfy global housing and modern infrastructure needs. As a consequence, the cement industry worldwide is facing growing challenges in conserving material and energy resources, as well as reducing its CO{sub 2} emissions. According to the International Energy Agency, the main levers for cement producers are the increase in energy efficiency and the use of alternative materials, be it as fuel or raw materials. Accordingly, the use of alternative fuels has already increased significantly in recent years, but potential for further increases still exists. In cement, the reduction of the clinker factor remains a key priority: tremendous progress has already been made. Nevertheless, appropriate materials are limited in their regional availability. New materials might be able to play a role as cement constituents in the future. It remains to be seen to what extent they could substitute Portland cement clinker to a significant degree.

Schneider, M., E-mail: sch@vdz-online.de [VDZ, Duesseldorf (Germany); Romer, M.; Tschudin, M. [Holcim Group Support Ltd, Holderbank (Switzerland); Bolio, H. [CEMEX, Monterrey (Mexico)

2011-07-15

14

The nature of the hydration products in hardened cement pastes  

Microsoft Academic Search

An understanding of the performance of portland cement-based materials requires knowledge at the microstructural level. Developments in the instrumentation of several techniques have led to improved understanding of the composition, morphology, and spatial distribution of the various products of cement hydration. In particular, our understanding of the nature of the nearly amorphous calcium silicate hydrate (C–S–H) phases – which are

I. G Richardson

2000-01-01

15

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

16

Environmental effects of cementation process on spent shale leachates  

Microsoft Academic Search

A methodology was developed wherein the increase in compressive strength, mineralogical changes and pore water composition were all studied simultaneously as a function of moisturized spent shale curing time. From these results the relationship between the nature of cementation process and the composition of pore water was established. Heavy metals were entrapped in the cementing constituents and the pore water

D. Marcus; S. A. Miller; D. A. Sangrey

1984-01-01

17

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

PubMed

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

Alp, I; Deveci, H; Süngün, H

2008-02-23

18

Follow up study of workers manufacturing chrysotile asbestos cement products.  

PubMed Central

A cohort study has been carried out of 2167 subjects employed between 1941 and 1983 at an asbestos cement factory in England. The production process incorporated the use of chrysotile asbestos fibre only, except for a small amount of amosite during four months in 1976. Measured airborne fibre concentrations available since 1970 from personal samplers showed mean levels below 1 fibre/ml, although higher levels had probably occurred previously in certain areas of the factory. No excess of lung cancer was observed in the mortality follow up by comparison with either national or local death rates, and analyses of subgroups of the workforce by job, exposure level, duration of employment, duration since entry, or calendar years of employment gave no real suggestion of an asbestos related excess for this cause of death. There was one death from pleural mesothelioma and one with asbestosis mentioned as an associated cause on the death certificate, but neither is thought to be linked to asbestos exposure at this factory. Other suggested asbestos related cancers, such as laryngeal and gastrointestinal, did not show raised risks. Although the durations of exposure were short in this study, the findings are consistent with two other studies of workers exposed to low concentrations of chrysotile fibre in the manufacture of asbestos cement products which reported no excess mortality.

Gardner, M J; Winter, P D; Pannett, B; Powell, C A

1986-01-01

19

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

20

Carbon dioxide capture from a cement manufacturing process  

DOEpatents

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

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

2011-07-12

21

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

PubMed

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

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

2012-04-26

22

Production of cements from Illinois coal ash. Technical report, September 1, 1995--November 30, 1995  

SciTech Connect

The objective of this program is to convert Illinois coal combustion residues, such as fly ash, bottom ash, and boiler slag, into novel cementitious materials for use in the construction industry. Currently only about 30% of the 5 million tons of these coal combustion residues generated in Illinois each year are utilized, mainly as aggregate. These residues are composed largely Of SiO{sub 2}, Al{sub 2}O{sub 3}, Fe{sub 2}O{sub 3}, MgO, and CaO, which are also the major components of cement. The process being developed in this program will use the residues directly in the manufacture of cement products. Therefore, a much larger amount of residues can be utilized. To achieve the above objective, in the first phase (current year) samples of coal combustion residues will be blended and mixed, as needed, with a lime or cement kiln dust (CKD) to adjust the CaO composition. Six mixtures will be melted in a laboratory-scale furnace at CTL. The resulting products will then be tested for cementitious properties. Two preliminary blends have been tested. One blend used fly ash with limestone, while the other used fly ash with CKD. Each blend was melted and then quenched, and the resulting product samples were ground to a specific surface area similar to portland cement. Cementitious properties of these product samples were evaluated by compression testing of 1-inch cube specimens. The specimens were formed out of cement paste where a certain percentage of the cement paste is displaced by one of the sample products. The specimens were cured for 24 hours at 55{degrees}C and 100% relative humidity. The specimens made with the product samples obtained 84 and 89% of the strength of a pure portland cement control cube. For comparison, similar (pozzolanic) materials in standard concrete practice are required to have a compressive strength of at least 75% of that of the control.

Wagner, J.C. [Institute of Gas Technology, Chicago, IL (United States); Bhatty, J.I.; Mishulovich, A. [Construction Technology Labs., Inc., Washington, DC (United States)

1995-12-31

23

Formulation of criteria for pollution control on cement products produced from solid wastes in China.  

PubMed

The process of producing cement products from solid waste can increase the level of pollutants in the cement products. Therefore, it is very important to establish a pollution control standard for cement products to protect the environment and human health. This paper presents acceptance limits for the availability of heavy metals in cement products which have been produced from solid wastes and explains how the limits have been calculated. The approach and method used to formulate these criteria were based on EN 12920. The typical exposure scenarios used in this paper involve concrete being used for drinking water supply pipelines and concrete pavements and are based on an analysis of typical applications of cement in China, and the potential for contact with water. The parameters of a tank test which was based on NEN 7375 were set in accordance with the environmental conditions of typical scenarios in China. Mechanisms controlling the release of heavy metals in concrete and a model for that release were obtained using the leaching test. Finally, based on acceptance criteria for drinking water and groundwater quality in China, limit values for the availability of heavy metals in concrete were calculated. PMID:21514989

Yang, Yufei; Huang, Qifei; Yang, Yu; Huang, Zechun; Wang, Qi

2011-04-22

24

In situ monitoring of the hydration process of KPS geopolymer cement with ESEM  

Microsoft Academic Search

Environmental scanning electron microscope (ESEM) was used to in situ quantitatively study the hydration process of K-PS geopolymer cement under an 80% RH environment. An energy dispersion X-ray analysis (EDXA) was also employed to distinguish the chemical composition of hydration product. The ESEM micrographs showed that metakaolin particles pack loosely at 10 min after mixing, resulting in the existence of

Wei Sun; Yun-sheng Zhang; Wei Lin; Zhi-yong Liu

2004-01-01

25

Recycling Coal Gangue as Raw Material for Portland Cement Production in Dry Rotary Kiln  

Microsoft Academic Search

Coal gangue (CG) is one of industrial solid wastes with biggest discharging. The disposal of such a large quantity of this solid waste requires lots of land and many serious environmental problems have been occurred. In this paper, CG as one of cement raw materials, and production experiments were performed in a 5000t-d-1 dry process rotary kiln to calcinations Portland

Guohua Qiu; Weiqiang Zeng; Zhenglun Shi; Leming Cheng; Zhongyang Luo

2010-01-01

26

Evaluation of cement production using a pressurized fluidized-bed combustor  

SciTech Connect

There are several primary conclusions which can be reached and used to define research required in establishing the feasibility of using PFBC-derived materials as cement feedstock. 1. With appropriate blending almost any material containing the required cement-making materials can be utilized to manufacture cement. However, extensive blending with multiple materials or the use of ash in relatively small quantities would compromise the worth of this concept. 2. The composition of a potential feedstock must be considered not only with respect to the presence of required materials, but just as significantly, with respect to the presence and concentration of known deleterious materials. 3. The processing costs for rendering the feedstock into an acceptable composition and the energy costs associated with both processing and burning must be considered. It should be noted that the cost of energy to produce cement, expressed as a percentage of the price of the product is higher than for any other major industrial product. Energy consumption is, therefore, a major issue. 4. The need for conformance to environmental regulations has a profound effect on the cement industry since waste materials can neither be discharged to the atmosphere or be shipped to a landfill. 5. Fifth, the need for achieving uniformity in the composition of the cement is critical to controlling its quality. Unfortunately, certain materials in very small concentrations have the capability to affect the rate and extent to which the cementitious compound in portland cement are able to form. Particularly critical are variations in the ash, the sulfur content of the coal or the amount and composition of the stack dust returned to the kiln.

DeLallo, M.; Eshbach, R.

1994-01-01

27

Development of a Polymeric Cementing and Encapsulating Process for Managing Hazardous Wastes.  

National Technical Information Service (NTIS)

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...

H. R. Lubowitz R. L. Derham L. E. Ryan G. A. Zakrzewski

1977-01-01

28

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

PubMed

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

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

2008-04-01

29

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

30

Well cementing process using presheared water swellable clays  

SciTech Connect

A method of preparing and using a cement slurry having water swellable clays therein as extenders for the cement is described. This method enhances the effectiveness of the water swellable clays by preshearing aqueous suspensions thereof prior to mixing these suspensions with cement to form a pumpable cement slurry. Also described is a particular technique for using bentonite as a cement extender in a cement slurry formed with salt water.

Messenger, J.U.

1980-05-13

31

A novel method to evaluate the setting process of cement and asphalt emulsion in CA mortar  

Microsoft Academic Search

Cement and asphalt mortar (CA mortar) is the key component in the structure of Shinkansen slab track and serves as the elastic\\u000a shock-absorber. A new method was put forward to evaluate the setting process of cement and asphalt emulsion (CAE) in CA mortar.\\u000a It was noted that the setting process was governed by several factors such as cement types, cement\\/asphalt

Fazhou Wang; Zhichao Liu; Tao Wang; Shuguang Hu

2008-01-01

32

High-alumina cement production from FeNi-ERF slag, limestone and diasporic bauxite  

Microsoft Academic Search

In this paper the utilization of ferronickel electroreduction furnace (FeNi-ERF) slag for the production of high-alumina cement (HAC) is investigated through laboratory and pilot-scale tests. The process followed consisted of smelting reduction of slag mixtures with low-grade diasporic bauxite and limestone. In the laboratory-scale trials the main process parameters were defined, concerning raw material proportions, kinetics of the reductions and

E. Dourdounis; V. Stivanakis; G. N. Angelopoulos; E. Chaniotakis; E. Frogoudakis; D. Papanastasiou; D. C. Papamantellos

2004-01-01

33

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

2008-11-13

34

Evaluation of normal-weight and light-weight fillers in extruded cellulose fiber cement products  

Microsoft Academic Search

Extruded fiber cement products offer advantages in terms of the versatility of section profiles, end product performance characteristics, and production throughput. Wood fibers offer a desirable balance of performance and cost as reinforcement in extruded wood fiber cement products. The research reported herein assessed the effects of normal-weight (silica sand) and light-weight (expanded shale) fillers on mechanical, physical and durability

Parviz Soroushian; Mohamed Elzafraney; Ali Nossoni; Habibur Chowdhury

2006-01-01

35

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

SciTech Connect

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

Hasanbeigi, Ali; Price, Lynn; Lin, Elina

2012-04-06

36

Effect of burning supplementary waste fuels on the pollutant emissions by cement plants: a statistical analysis of process data  

Microsoft Academic Search

This paper shows how some statistical tools can be applied in the process analysis of real plant data, e.g. in the clinker production process by using alternative fuels (shredded tyres and waste oils) as alternative fuels in clinker kilns of two different cement plants. Statistical Student's t-tests, stepwise linear regression models and factor analysis were employed in the data analysis

M. Prisciandaro; G. Mazziotti; F. Veglió

2003-01-01

37

A PROCEDURE FOR PROCESSING MIXTURES OF SOIL, CEMENT, AND SUGAR CANE BAGASSE  

Microsoft Academic Search

Two schemes for processing mixtures of soil, cement, and sugar cane bagasse have been investigated to determine the best way of processing house construction bricks for rural Africa. In one case, bagasse fibers were treated for removing sugar while untreated bagasse fibers were used in the other one. Processing house construction bricks from soil, cement, and untreated bagasse turned out

R. Medjo Eko; G. L. Riskowski

38

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

SciTech Connect

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

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

2006-01-15

39

Radiological Waste Processing for the Recovery of Silver through Cementation with Zinc Powder  

Microsoft Academic Search

The recovery of silver from silver-thiosulphate-fixer solutions of radiological wastes has been studied by cementation in batch-stirred reactors using zinc powder as the cementing agent. Silver is efficiently recovered from the solutions. The silver recovery rate and the total silver recovery increased with pH. Metallic silver was the product for cementation in deoxygenated solutions at all pH studied. With non-deoxygenated

V. Ibarra Galván; A. G. Mendoza Ruelas; A. López Valdivieso

2009-01-01

40

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...

41

Polymeric calcium phosphate cements: analysis of reaction products and properties.  

PubMed

Chemical and mechanical properties of water-based polymeric calcium phosphate cements (PCPC) were investigated. These cements were derived from mixing several types of water-soluble polymers, e.g., gelatin, poly(vinyl alcohol) (PVA), and poly(alkenoic acids) such as poly(acrylic acid), with a calcium phosphate cement (CPC) mixture consisting of equimolar amounts of tetracalcium phosphate (TTCP) and anhydrous dicalcium phosphate (DCPA) as well as several other TTCP-containing mixtures. Cement formation was observed with all of the PCPCs. With the gelatin and PVA cements, significant amounts of hydroxyapatite (HA) formation were observed within 24 h. Their setting times and mechanical properties were similar to those of the purely inorganic CPC that is derived from the reaction of TTCP and DCPA in water. Although the mechanical properties of a gelatin-CPC cement were only slightly improved, its handling characteristics were superior to that of CPC. Significantly faster setting and stronger cements were obtained using polycarboxylic acid polymers with CPC. However, only small amounts of HA were observed in these types of polymeric cements even after 1 mon storage in distilled water at 37 degrees C. This research demonstrates the feasibility of preparing several new types of dental cements based on the interaction of water-soluble polymers with a self-setting calcium phosphate powder mixture. PMID:8299869

Miyazaki, K; Horibe, T; Antonucci, J M; Takagi, S; Chow, L C

1993-01-01

42

Improved control of the finish grinding process in cement manufacture  

SciTech Connect

Activities developed on Task 6 of the Cement Clinker Project from July 1, 1985 to September 30, 1985 are described in this progress report. Results on eight continuous ball mill tests are included. Experimentation was performed in a 0.99 m diameter air-swept mill at the Kennedy Van Saun facilities in Danville. In the first four runs, the effect of production rate on size distribution of product was tested for the powder filling level around 0.83. In the other tests, the powder filling was changed between 0.7 and 1.25. A preliminary analysis of the results indicates that the internal classification curve is moving in a narrow band even when the product size distribution is strongly affected by the different experimented condition. Also the direct scale-up results from the 8 inch diameter batch mill to the 0.99 mill diameter in batch mode is reported. Predictions overestimate capacity for short times of grinding but they are in good agreement for long times. The presence of components having large and small rate of breakage and occurrence of abnormal breakage are discussed. Future work includes detailed analysis of the data and simulation of continuous test results.

Menacho, J.M.; Austin, L.G.; Cuhadaroglu, M.S. (Pennsylvania State Univ., University Park, PA (USA). Dept. of Mineral Processing)

1985-01-01

43

Method for simultaneously scrubbing cement kiln exhaust gas and producing useful by-products therefrom  

Microsoft Academic Search

A method of simultaneously scrubbing acidic oxides of sulfur, nitrogen and carbon from the hot exhaust stream from a cement kiln and utilizing acids derived therefrom to produce useful products from the carbonates and oxides of alkali and alkaline earth metals contained as solids in cement kiln dust comprising the carbonates and oxides and insoluble silicates, aluminates and iron compounds

1987-01-01

44

Air Quality and Cement Production: Examining the Implications of Point Source Pollution in Sri Lanka  

Microsoft Academic Search

Suspended particulate matter (SPM), dust, fumes and gases from cement production can result in a range of health effects to households living around factories. This study estimates the health costs associated with air pollution from a cement factory in the district of Puttalam in Sri Lanka. The study uses field data collected from 500 households living within a 3 km

Cyril Bogahawatte; Janaranjana Herath

45

Production of cements from Illinois coal ash. Final technical report, September 1, 1995--August 31, 1996  

SciTech Connect

The objective of this program is to convert Illinois coal combustion residues, such as fly ash, bottom ash, and boiler slag, into novel cementitious materials for use in the construction industry. These residues are composed largely of SiO{sub 2}, Al{sub 2}O{sub 3}, Fe{sub 2}O{sub 3}, MgO, and CaO, which are also the major components of cement. Since the residues are used as an integral component of the cement and not just as additives to concrete, larger amounts of the residues can be utilized. The process uses submerged combustion to melt blends of coal combustion residues with lime, clay, and/or sand. The submerged combustion melter utilizes natural gas-oxidant firing directly into a molten bath to provide efficient melting of mineral-like materials. Use of this melter for cement production has many advantages over rotary kilns including very little, if any, grinding of the feed material, very low emissions, and compact size. During the first year of the program, samples of coal combustion residues were blended and mixed, as needed; with lime, clay, and/or sand to adjust the composition. Six mixtures, three with fly ash and three with bottom ash, were melted in a laboratory-scale furnace. The resultant products were used in mortar cubes and bars which were subjected to ASTM standard tests of cementitious properties. In the hydraulic activity test, mortar cubes were found to have a strength comparable to standard mortar cements. In the compressive strength test, mortar cubes were found to have strengths that exceeded ASTM blended cement performance specifications. In the ASR expansion test, mortar bars were subjected to alkali-silica reaction-induced expansion, which is a problem for siliceous aggregate-based concretes that are exposed to moisture. The mortar bars made with the products inhibited 85 to 97% of this expansion. These results show that residue-based products have an excellent potential as ASR-preventing additions in concretes.

Wagner, J.C.; Bhatty, J.L.; Mishulovich, A.

1997-05-01

46

The processing, mechanical properties and bioactivity of zinc based glass ionomer cements  

Microsoft Academic Search

The suitability of Glass Ionomer Cements (GICs) for use in orthopaedics is retarded by the presence in the glass phase of aluminium, a neurotoxin. Unfortunately, the aluminium ion plays an integral role in the setting process of a GIC and its absence is likely to hinder cement formation. However, zinc oxide, a bacteriocide, can act both as a network modifying

D. Boyd; M. R. Towler

2005-01-01

47

Specifications and Protocols for Acceptance Tests on Processing Additions in Cement Manufacturing.  

National Technical Information Service (NTIS)

Inorganic processing additions (referred to as processing additions or PAs hereafter), such as granulated blast furnace slag and fly ash, are interground with clinker in the manufacture of some portland cements, primarily to improve the efficiency of manu...

P. C. Taylor

2008-01-01

48

Ultrasonic Characterization of the Curing Process of Polymethylmethacrylate-based Bone Cement Modified with Hydroxyapatite  

NASA Astrophysics Data System (ADS)

The use of polymethylmethacrylate (PMMA)-based bone cement for implantation of metallic prostheses is becoming increasingly common. Failure of a cemented prosthesis often occurs when there is weak bonding at the bone/cement or cement/metal interface. The addition of hydroxyapatite (HA) particles, a synthetically produced version of the natural mineral in bone, may improve the adhesion by promoting bone growth into the cement itself. The curing time of PMMA bone cement determines the speed of implant insertion, which can affect the mechanical strength of the cement. Pure PMMA has a well-characterized curing time of 9-12 minutes, depending on environmental factors such as temperature and humidity. By measuring the propagation of ultrasonic pulses through a sample of bone cement, the curing process can be monitored. As the material hardens, the velocity of an ultrasonic pulse increases, and the attenuation decreases. These parameters were measured as a function of time for PMMA mixed with 0, 10 and 30investigation of the curing process as a function of hydroxyapatite concentration.

Viano, Ann; Auwarter, Julie; Hoffmeister, Brent; Rho, Jae-Young

2000-03-01

49

Manufacture and properties of fluoride cement  

NASA Astrophysics Data System (ADS)

This research work aimed at characterising composition, hydration and physical properties of fluoride cement, by studying samples of the cement obtained from Malawi, and comparing them to ordinary Portland cement. By confirming the suitable characteristics of fluoride cement through this work, the results of the research work provide a good basis for the wider adoption of fluoride cement as an alternative to ordinary Portland cement, especially in developing economies. Numerous accounts have been cited regarding the production and use of fluoride cement. Since there have not been conclusive agreement as to its properties, this study was limited to the theories of successful incorporation of fluoride compounds in the manufacture of fluoride cement. Hence, the properties and characteristics reported in this study relate to the cement currently manufactured in Malawi, and, on a comparative basis only, to that manufactured in other parts of the world. Samples of the fluoride cement used in the study were obtained by synthetic manufacture of the cement using common raw materials for the manufacture of fluoride cement that is limestone, silica sand, and fluorspar. These samples were subjected to several comparative tests used to characterise cements including examination under x-ray diffractometer, scanning electron microscopy and tests for setting time and compressive strength. Under similar laboratory conditions, it was possible to prove that fluoride cement hardens more rapidly than ordinary Portland cement. Also observed during the experimental work is that fluoride cement develops higher compressive strengths than ordinary Portland cement. The hardening and setting times are significantly different between the two cements. Also the nature of the hydration products, that is the microstructural development is significantly different in the two cements. The differences brought about between the two cements are because of the presence of fluorine during the clinkering process. It was observed in the laboratory simulated production of fluoride cement, that the clinkering temperature is much lower (around 1 170 °C) compared to that for the production of ordinary Portland cement. The other observed differences were attributed to the different mineralogical composition as a result of fluoride incorporation into the cement. While fluorine content is very minimal in fluoride cement, not more than 2 %, the resulting cementitious products are altered significantly as was observed from the study. Part of the experimental results has been used as reference material in the preparation of a draft Malawi Standard on fluoride cement. This draft standard will be submitted to the Malawi Bureau of Standards for further processing before it can be officially endorsed as a Malawi Standard.

Malata-Chirwa, Charles David

50

International Forum on Appropriate Industrial Technology, Held at New Delhi/Anand, India on November 20-30, 1978. Appropriate Technologies for Small-Scale Production of Cement and Cementitious Materials.  

National Technical Information Service (NTIS)

The report discusses small scale cement production, and the characteristics and problems in existing cement-production technology. The report covers small-scale Portland plants; lime-based cementing materials; other cementing materials such as hydraulic l...

R. J. S. Spence

1978-01-01

51

Nanotechnology Applications for Sustainable Cement-Based Products  

NASA Astrophysics Data System (ADS)

Concrete is a macro-material strongly influenced by the properties of its components and hydrates at the nanoscale. Progress at this level will engender new opportunities for improvement of strength and durability of concrete materials. This article will focus on recent research work in the field of nanoscience applications to cement and concrete at the NRC-IRC. A particular attention will be given to nanoparticles and cement-based nanocomposites.

Raki, L.; Beaudoin, J. J.; Alizadeh, R.

52

Change in cement manufacturing process, a cause for decline in chromate allergy?  

PubMed

Hexavalent chromate in cement is the commonest cause of allergic contact dermatitis, especially among construction workers. Over the past decades, there has been a general decline in the prevalence of chromate allergy among construction workers. We suspect that a change in the constituents of cement, resulting in the lowering of hexavalent chromate, contributed to the decline. Slag (free from hexavalent chromate) from the iron-quenched, blast furnace process has been used as a substitute for clinker (which contains high hexavalent chromate) in manufacturing cement. As a result, the slag has diluted the hexavalent chromate content of cement. Our analytical study showed that slag is free from hexavalent chromate and that the hexavalent chromate of clinker ranged from 6-17 micrograms/g. Substituting slag for clinker resulted in dilution of hexavalent chromate in the cement. The hexavalent chromate content of cement declines proportionately with increasing proportion of slag, e.g., a cement containing 5% slag has a total hexavalent chromate concentration of 17.5 micrograms/g, whereas increasing the proportion of slag to 60% reduced the hexavalent chromate content to 7.1 micrograms/gm in the same cement. PMID:8789226

Goh, C L; Gan, S L

1996-01-01

53

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

National Technical Information Service (NTIS)

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

1976-01-01

54

Barnacle Balanus amphitrite adheres by a stepwise cementing process.  

PubMed

Barnacles adhere permanently to surfaces by secreting and curing a thin interfacial adhesive underwater. Here, we show that the acorn barnacle Balanus amphitrite adheres by a two-step fluid secretion process, both contributing to adhesion. We found that, as barnacles grow, the first barnacle cement secretion (BCS1) is released at the periphery of the expanding base plate. Subsequently, a second, autofluorescent fluid (BCS2) is released. We show that secretion of BCS2 into the interface results, on average, in a 2-fold increase in adhesive strength over adhesion by BCS1 alone. The two secretions are distinguishable both spatially and temporally, and differ in morphology, protein conformation, and chemical functionality. The short time window for BCS2 secretion relative to the overall area increase demonstrates that it has a disproportionate, surprisingly powerful, impact on adhesion. The dramatic change in adhesion occurs without measurable changes in interface thickness and total protein content. A fracture mechanics analysis suggests the interfacial material's modulus or work of adhesion, or both, were substantially increased after BCS2 secretion. Addition of BCS2 into the interface generates highly networked amyloid-like fibrils and enhanced phenolic content. Both intertwined fibers and phenolic chemistries may contribute to mechanical stability of the interface through physically or chemically anchoring interface proteins to the substrate and intermolecular interactions. Our experiments point to the need to reexamine the role of phenolic components in barnacle adhesion, long discounted despite their prevalence in structural membranes of arthropods and crustaceans, as they may contribute to chemical processes that strengthen adhesion through intermolecular cross-linking. PMID:22721507

Burden, Daniel K; Barlow, Daniel E; Spillmann, Christopher M; Orihuela, Beatriz; Rittschof, Daniel; Everett, R K; Wahl, Kathryn J

2012-07-11

55

Utilization of municipal sewage sludge as additives for the production of eco-cement.  

PubMed

The effects of using dried sewage sludge as additive on cement property in the process of clinker burning were investigated in this paper. The eco-cement samples were prepared by adding 0.50-15.0% of dried sewage sludge to unit raw meal, and then the mixtures were burned at 1450 °C for 2 h. The results indicated that the major components in the eco-cement clinkers were similar to those in ordinary Portland cement. Although the C(2)S phase formation increased with the increase of sewage sludge content, it was also found that the microstructure of the mixture containing 15.0% sewage sludge in raw meal was significantly different and that a larger amount of pores were distributed in the clinker. Moreover, all the eco-cement pastes had a longer initial setting time and final setting time than those of plain cement paste, which increased as the sewage sludge content in the raw meal increased. All the eco-cement pastes had lower early flexural strengths, which increased as the sewage sludge content increased, while the compressive strengths decreased slightly. However, this had no significant effect on all the strengths at later stages. Furthermore, the leaching concentrations of all the types of eco-cement clinkers met the standard of Chinese current regulatory thresholds. PMID:22386820

Lin, Yiming; Zhou, Shaoqi; Li, Fuzhen; Lin, Yixiao

2012-02-16

56

Examination of the jarosite-alunite precipitate addition in the raw meal for the production of sulfoaluminate cement clinker.  

PubMed

The aim of the present research work was to investigate the possibility of adding a jarosite-alunite chemical precipitate, a waste product of a new hydrometallurgical process developed to treat economically low-grade nickel oxides ores, in the raw meal for the production of sulfoaluminate cement clinker. For that reason, two samples of raw meals were prepared, one contained 20% gypsum, as a reference sample ((SAC)Ref) and another with 11.31% jarosite-alunite precipitate ((SAC)J/A). Both raw meals were sintered at 1300 degrees C. The results of chemical and mineralogical analyses as well as the microscopic examination showed that the use of the jarosite-alunite precipitate did not affect the mineralogical characteristics of the so produced sulfoaluminate cement clinker and there was confirmed the formation of the sulfoaluminate phase (C4A3S), the most typical phase of this cement type. Furthermore, both clinkers were tested by determining the grindability, setting time, compressive strength and expansibility. The hydration products were examined by XRD analysis at 2, 7, 28 and 90 days. The results of the physico-mechanical tests showed that the addition of jarosite-alunite precipitate did not negatively affect the quality of the produced cement. PMID:16223566

Katsioti, M; Tsakiridis, P E; Leonardou-Agatzini, S; Oustadakis, P

2005-10-11

57

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

SciTech Connect

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

Sun Wei; Zhang Yunsheng; Lin Wei; Liu Zhiyong

2004-06-01

58

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

PubMed

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

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

2008-11-05

59

Wear Processes on Cemented Carbide Tools Used in Cutting Steel  

Microsoft Academic Search

The conditions of wear from the faces of cemented carbide cutting tools are described. The particular conditions on the top surface of a cutting tool where the thin ribbon, or chip, of metal with a freshly exposed surface flows in contact with the tool over a relatively long path, lead to the generation of high temperatures at the friction surface.

E. M. Trent

1952-01-01

60

Reactive transport modeling of interaction processes between claystone and cement  

Microsoft Academic Search

The disposal of radioactive wastes in clayey formations may require the use of large amounts of concrete and cement. The chemical interactions between these industrial materials and the host rock are modeled with the reactive transport code HYTEC for time scales and a geometry representative of disposal projects. The pH evolution, a key parameter in element mobility, is studied more

L. De Windt; D. Pellegrini; J. van der Lee

61

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

62

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

63

Development of the process regime for cementing salt concentrates from the Volgodonsk nuclear power plant  

Microsoft Academic Search

The results of work on the development of the process regime for cementing salt concentrates from the Volgodonsk nuclear power\\u000a plant are presented. Experiments on model and real bottoms residues from liquid-wastes storage tanks show that additionally\\u000a concentrating the wastes and regulating the alkalinity can yield cement compounds with dry residue content up to 30% percent.\\u000a Portland and slag portland

K. P. Zakharova; O. M. Khimchenko; L. P. Sukhanov; V. V. Aleksandrov; A. A. Sal’nikov; E. V. Khromovskikh; V. M. Pushkarev

2007-01-01

64

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

Microsoft Academic Search

The objective of this study was to estimate the contribution of a facility that processes steel production slag into raw material for cement production to local outdoor particle deposition in Camden, NJ. A dry deposition sampler that can house four 37-mm quartz fiber filters was developed and used for the collection of atmospheric particle deposits. Two rounds of particle collection

Chang Ho Yu; Zhihua Fan; Elizabeth McCandlish; Alan H. Stern; Paul J. Lioy

2011-01-01

65

Sculpting with Cement.  

ERIC Educational Resources Information Center

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

Olson, Lynn

1983-01-01

66

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

Microsoft Academic Search

Cement rotary kiln co-processing of hazardous wastes and cement based solidification\\/stabilization could both immobilize heavy metals. The different retention mechanisms of the two technologies lead to different fixation effects of heavy metals. The same amount of heavy metal compounds were treated by the two types of fixation technologies. Long-term leaching test (160 days), the maximum availability leaching test (NEN 7341)

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

2009-01-01

67

The structure of a glass-ionomer cement and its relationship to the setting process.  

PubMed

The G-200 glass of the glass-ionomer cement has two phases: a continuous calcium aluminosilicate matrix and partly crystalline calcium fluoride-rich droplets, the nature of which depend on the thermal history of the glass. The setting process of the cement takes place when the glass is mixed with poly(acrylic acid). It has two overlapping stages corresponding to the rapid leaching of calcium ions from the uncrystalline part of the droplets, followed by the slower release of aluminum (and some calcium) from the main glass phase. These processes are affected by the microstructure and microcomposition of the glass. PMID:284041

Barry, T I; Clinton, D J; Wilson, A D

1979-03-01

68

PRODUCTION AND PROPERTIES OF A MEDIUM DENSITY WOOD-CEMENT BOARDS PRODUCED WITH ORIENTED STRANDS AND SILICA FUME  

Microsoft Academic Search

Wood-cement board (WCB) is a panel product that has the advantages of inorganic and organic materials. However, the main problems affecting the manufacture and use of WCB are the inhibitory effects of wood on the setting of cement and the high specific gravity of the final product. This paper examines the potential of strand orientation and the use of silica

Henrique Soares; Del Menezzi; Vinicius Gomes de Castro; Mário Rabelo de Souza

2007-01-01

69

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; Yoon, E.S. [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

1999-02-01

70

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

Microsoft Academic Search

The use of life-cycle assessment (LCA) to understand the embodied energy, environmental impacts, and potential energy-savings of manufactured products has become more widespread among researchers in recent years. This paper reviews recent LCA studies in the cement industry in China and in other countries and provides an assessment of the methodology used by the researchers compared to ISO LCA standards

Hongyou Lu; Eric Masanet; Lynn Price

2009-01-01

71

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

72

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...

73

Capture of green-house carbon dioxide in Portland cement.  

National Technical Information Service (NTIS)

A novel process has been developed to sequester green-house carbon dioxide produced by the cement industry in precast cement products. Typically, 10--24 wt % of CO(sub 2) produced by calcination of calcium carbonate during clinkering of the cement may be ...

A. S. Wagh D. Singh J. Pullockaran L. Knox

1993-01-01

74

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

EPA Science Inventory

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

75

Sintering features of cemented carbides WC–Co processed from fine powders  

Microsoft Academic Search

Since the last 30 years, the cemented carbides WC–Co are processed from finer and finer powders. Both densification behaviour and microstructure evolution along the liquid-phase sintering (LPS) are different for materials prepared from powders of micronic or submicronic size. The typical features induced by the use of submicronic particles – large contribution of the solid-state densification, abnormal growth – are

C. H. Allibert

2001-01-01

76

Testing and evaluation of alternative process systems for immobilizing radioactive mixed particulate waste in cement  

SciTech Connect

Radioactive and Hazardous Mixed Wastes have accumulated at the Department of Energy (DOE) Hanford Site in south-central Washington State. Ongoing operations and planned facilities at Hanford will also contribute to this waste stream. To meet the Resource Conservation and Recovery Act (RCRA) Land Disposal Restrictions most of this waste will need to be treated to permit disposal. In general this treatment will need to include stabilization/solidification either as a sole method or as part of a treatment train. A planned DOE facility, the Waste Receiving and Processing (WRAP) Module 2A, is scoped to provide this required treatment for containerized contact-handled (CH), mixed low-level waste (MLLW) at Hanford. An engineering development program has been conducted by Westinghouse Hanford Company (WHC) to select the best system for utilizing a cement based process in WRAP Module 2A. Three mixing processes were developed for analysis and testing; in-drum mixing, continuous mixing, and batch mixing. Some full scale tests were conducted and 55 gallon drums of solidified product were produced. These drums were core sampled and examined to evaluate mixing effectiveness. Total solids loading and the order of addition of waste and binder constituents were also varied. The highest confidence approach to meet the WRAP Module 2A waste immobilization system needs appears to be the out-of-drum batch mixing concept. This system is believed to offer the most flexibility and efficiency, given the highly variable and troublesome waste streams feeding the facility.

Weingardt, K.M.; Weber, J.R.

1994-03-01

77

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

PubMed

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

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

2013-01-01

78

Polyacrylamide induced flocculation of a cement suspension  

Microsoft Academic Search

The use of cellulose, instead of asbestos, in the fibre cement composites manufacture, using the Hatschek process, reduces cement retention and makes necessary to use a flocculant which is crucial for the plant productivity. The use of different types and doses of polyacrylamides (PAM) as well as the addition process, have been studied to obtain an in-depth knowledge of floc

Carlos Negro; Luis M. Sánchez; Elena Fuente; Ángeles Blanco; Julio Tijero

2006-01-01

79

Capture of green-house carbon dioxide in Portland cement  

SciTech Connect

A novel process has been developed to sequester green-house carbon dioxide produced by the cement industry in precast cement products. Typically, 10--24 wt % of CO{sub 2} produced by calcination of calcium carbonate during clinkering of the cement may be captured. The carbonation process also cures the cement paste within minutes into hard bodies. The process maintains high pH conditions during curing, to allow conventional steel reinforcement of concrete. The process will save time and money to the cement industry, and at the same time, help them to comply with the Clean Air Act by sequestering the green-house carbon dioxide.

Wagh, A.S.; Singh, D.; Pullockaran, J.; Knox, L.

1993-12-31

80

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

81

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

SciTech Connect

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 {sup o}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{sub 3}Cr{sub 2}(SiO{sub 4}){sub 3}] and a pink malayaite-based pigment [Ca(Sn,Cr)SiO{sub 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.

Gualtieri, Alessandro F., E-mail: alessandro.gualtieri@unimore.it [Dipartimento di Scienze della Terra, Universita di Modena e R.E., Via S. Eufemia 19, I-41100 Modena (Italy); Giacobbe, Carlotta; Sardisco, Lorenza; Saraceno, Michele [Dipartimento di Scienze della Terra, Universita di Modena e R.E., Via S. Eufemia 19, I-41100 Modena (Italy); Lassinantti Gualtieri, Magdalena [Dipartimento Ingegneria dei Materiali e dell'Ambiente, Universita di Modena e Reggio Emilia, Via Vignolese 905/a, I-41100 Modena (Italy); Lusvardi, Gigliola [Dipartimento di Chimica, Universita degli Studi di Modena e Reggio Emilia, Via G. Campi 183, I-41100 Modena (Italy); Cavenati, Cinzia; Zanatto, Ivano [ZETADI S.r.l., Via dell'Artigianato 10, Ferno (Italy)

2011-01-15

82

The Impact of Thermocycling Process on the Dislodgement Force of Different Endodontic Cements  

PubMed Central

To evaluate the effects of thermocycling (500 cycles, 5°C/55°C) on the push-out bond strength of calcium silicate based cements including WMTA, Nano-WMTA, and Bioaggregate to root dentin. Forty-eight dentin slices were prepared and divided into 3 groups (n = 16) and filled with Angelus WMTA, Nano-WMTA, or Bioaggregate. After incubation, half of the samples were thermocycled while the other half remained untreated. Push-out bond strength was calculated, and the modes of the bond failures were determined by SEM. The highest bond strength was seen in nonthermocycled Nano-WMTA samples and the lowest in thermocycled Bioaggregate samples. The significant differences between nonthermocycled and thermocycled samples were only noticed in WMTA and Nano-WMTA groups (P < 0.001). The mode of failure for thermocycled samples of all three cements was mostly cohesive. Thermocycling process can drastically affect the push-out bond strength of calcium silicate based cements. The intrastructural damages occurred due to the thermal stresses, causing cohesive failures in set materials. Sealing property of endodontic cements which have experienced the thermal stresses can be jeopardized due to occlusal forces happening in furcation cites.

Saghiri, Mohammad Ali; Asatourian, Armen; Garcia-Godoy, Franklin; Gutmann, James L.; Sheibani, Nader

2013-01-01

83

The impact of thermocycling process on the dislodgement force of different endodontic cements.  

PubMed

To evaluate the effects of thermocycling (500 cycles, 5°C/55°C) on the push-out bond strength of calcium silicate based cements including WMTA, Nano-WMTA, and Bioaggregate to root dentin. Forty-eight dentin slices were prepared and divided into 3 groups (n = 16) and filled with Angelus WMTA, Nano-WMTA, or Bioaggregate. After incubation, half of the samples were thermocycled while the other half remained untreated. Push-out bond strength was calculated, and the modes of the bond failures were determined by SEM. The highest bond strength was seen in nonthermocycled Nano-WMTA samples and the lowest in thermocycled Bioaggregate samples. The significant differences between nonthermocycled and thermocycled samples were only noticed in WMTA and Nano-WMTA groups (P < 0.001). The mode of failure for thermocycled samples of all three cements was mostly cohesive. Thermocycling process can drastically affect the push-out bond strength of calcium silicate based cements. The intrastructural damages occurred due to the thermal stresses, causing cohesive failures in set materials. Sealing property of endodontic cements which have experienced the thermal stresses can be jeopardized due to occlusal forces happening in furcation cites. PMID:24063004

Saghiri, Mohammad Ali; Asatourian, Armen; Garcia-Godoy, Franklin; Gutmann, James L; Sheibani, Nader

2013-08-24

84

Investigative and management techniques for cement kiln dust and pulp and paper process wastes  

SciTech Connect

Knowledge of the characteristics of industrial process wastes allows for some innovative and cost savings techniques for investigating and managing these wastes over conventional methods. This paper explores examples of some of these techniques employed on cement kiln dust (CKD) and pulp and paper mill process waste. Similar to Portland Cement, unleached CKD contains free lime and sources of reactive silica and/or alumina. Thus, it can set up in the presence of water. Properly moisture-conditioned CKD has been successfully used in Michigan as a landfill liner and cover material on closures of old CKD piles and newly permitted fills. However, CKD also contains high concentrations of soluble salts and when improperly managed can generate a leachate with high total dissolved solid concentrations. Surface and downhole geophysical methods employing electromagnetic conductivity have proven effective in delineating the horizontal and vertical extent of groundwater plumes caused by releases of CKD leachate.

Peters, C.S. [RMT, Inc., Okemos, MI (United States)

1998-12-31

85

Release of asbestos fibers from weathered and corroded asbestos cement products  

SciTech Connect

The controversy on whether weathered and corroded asbestos cement products are emitting biologically significant asbestos fiber concentrations in ambient air has not been resolved. Nor is it known if the weathered and corroded asbestos cement products release asbestos fibers which have the same carcinogenic potency as standard chrysotile. The purpose of this research project was to develop a method for sampling and measuring asbestos fiber emissions from solid planar surfaces (i.e., roofs and facades) consisting of asbestos cement products and to develop methods for studying the physical and chemical changes and the carcinogenic potency of the emitted fibers. Using this method asbestos fiber emissions in ambient air have been measured in the FRG during 1984/1986. The emissions of asbestos fibers longer than 5 microns were in the range 10(6) to 10(8) fibers/m2.hr. The ambient air concentrations of these asbestos fibers were for the most part less than 10(3) fibers/m3. It was shown that the emitted asbestos fibers were chemically changed and it was shown with animal experiments that their carcinogenic potency did not differ from the carcinogenicity of standard chrysotile fibers.

Spurny, K.R.

1989-02-01

86

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

Microsoft Academic Search

Stabilization\\/solidification (s\\/s) has been routinely used for the final treatment of hazardous wastes prior to land disposal. These processes involve adding one or more solidifying reagents into the waste to transform it into a monolithic solid with improved structural integrity. Cement-based systems with partial replacement by pulverized fuel ash (PFA) have been widely used to minimize leaching of contaminants from

C. S. Poon; X. C. Qiao; C. R. Cheeseman; Z. S. Lin

2006-01-01

87

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

PubMed

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

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

2010-02-01

88

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

SciTech Connect

In this study, the microwave materials interactions were studied through dielectric property measurements, process modeling, and lab scale microwave hybrid calcination tests. Characterization and analysis were performed to evaluate material reactions and energy usage. Processing parameters for laboratory scale and larger scale calcining experiments were developed for MAT limestone calcination. Early stage equipment design concepts were developed, with a focus on microwave post heating treatment. The retrofitting of existing rotary calcine equipment in the lime industry was assessed and found to be feasible. Ceralink sought to address some of the major barriers to the uptake of MAT identified as the need for (1) team approach with end users, technology partners, and equipment manufacturers, (2) modeling that incorporates kiln materials and variations to the design of industrial microwave equipment. This project has furthered the commercialization effort of MAT by working closely with an industrial lime manufacturer to educate them regarding MAT, identifying equipment manufacturer to supply microwave equipment, and developing a sophisticated MAT modeling with WPI, the university partner. MAT was shown to enhance calcining through lower energy consumption and faster reaction rates compared to conventional processing. Laboratory testing concluded that a 23% reduction in energy was possible for calcining small batches (5kg). Scale-up testing indicated that the energy savings increased as a function of load size and 36% energy savings was demonstrated (22 kg). A sophisticated model was developed which combines simultaneous microwave and conventional heating. Continued development of this modeling software could be used for larger scale calcining simulations, which would be a beneficial low-cost tool for exploring equipment design prior to actual building. Based on these findings, estimates for production scale MAT calcining benefits were calculated, assuming uptake of MAT in the US lime industry. This estimate showed that 7.3 TBTU/year could be saved, with reduction of 270 MMlbs of CO2 emissions, and $29 MM/year in economic savings. Taking into account estimates for MAT implementation in the US cement industry, an additional 39 TBTU/year, 3 Blbs of CO2 and $155 MM/year could be saved. One of the main remaining barriers to commercialization of MAT for the lime and cement industries is the sheer size of production. Through this project, it was realized that a production size MAT rotary calciner was not feasible, and a different approach was adapted. The concept of a microwave post heat section located in the upper portion of the cooler was devised and appears to be a more realistic approach for MAT implementation. Commercialization of this technology will require (1) continued pilot scale calcining demonstrations, (2) involvement of lime kiln companies, and (3) involvement of an industrial microwave equipment provider. An initial design concept for a MAT post-heat treatment section was conceived as a retrofit into the cooler sections of existing lime rotary calciners with a 1.4 year payback. Retrofitting will help spur implementation of this technology, as the capital investment will be minimal for enhancing the efficiency of current rotary lime kilns. Retrofits would likely be attractive to lime manufacturers, as the purchase of a new lime kiln is on the order of a $30 million dollar investment, where as a MAT retrofit is estimated on the order of $1 million. The path for commercialization lies in partnering with existing lime kiln companies, who will be able to implement the microwave post heat sections in existing and new build kilns. A microwave equipment provider has been identified, who would make up part of the continued development and commercialization team.

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

2012-02-10

89

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

90

Cement Evaluation Tool: A New Approach to Cement Evaluation  

Microsoft Academic Search

Cement bond logging achieves its greatest utility when it provides the production engineer with precise indications of cement strength and distribution around the casing. Zone isolation is of critical importance in production. Previous logging systems have yielded measures of cement bond that were circumferential averages of cement quality. These were difficult to interpret. Additionally, they were sensitive to the degree

Benoit Froelich; A. Dumont; Dennis Pittman; Bruno Seeman

1982-01-01

91

Phase development in the hardening process of two calcium phosphate bone cements: an energy dispersive X-ray diffraction study  

SciTech Connect

This work was aimed at the application of an energy dispersive X-ray diffraction technique to study the kinetics of phase development during the setting and hardening reactions in two calcium phosphate bone cements. The cements under study are based on either tricalcium phosphate or tetracalcium phosphate initial solid phase, and a magnesium carbonate-phosphoric acid liquid phase as the hardening liquid. The application of the energy dispersive X-ray diffraction method allowed to collect the diffraction patterns from the cement pastes in situ starting from 1 min of the setting and hardening process. The only crystallized phase in both cements was apatite-like phase, the primary crystallization process proceeds during a few seconds of the setting reaction. Both the compressive strength and the pH value changes during the hardening period can be attributed to the transformations occurring in the intergranular X-ray amorphous phase.

Generosi, A. [Istituto di Struttura della Materia, CNR, via del Fosso del Cavaliere, 100-00133 Rome (Italy); Smirnov, V.V. [Institute for Physical Chemistry of Ceramics, Russian Academy of Sciences, Ozernaya 48, Moscow 119361 (Russian Federation); Rau, J.V. [Istituto per lo Studio dei Materiali Nanostrutturati, CNR, Piazzale Aldo Moro, 5-00185 Rome (Italy); Albertini, V. Rossi [Istituto di Struttura della Materia, CNR, via del Fosso del Cavaliere, 100-00133 Rome (Italy); Ferro, D. [Istituto per lo Studio dei Materiali Nanostrutturati, CNR, Piazzale Aldo Moro, 5-00185 Rome (Italy); Barinov, S.M. [Institute for Physical Chemistry of Ceramics, Russian Academy of Sciences, Ozernaya 48, Moscow 119361 (Russian Federation)], E-mail: barinov_s@mail.ru

2008-03-04

92

ALARA Design Review for the Resumption of the Plutonium Finishing Plant (PFP) Cementation Process Project Activities  

SciTech Connect

The requirements for the performance of radiological design reviews are codified in 10CFR835, Occupational Radiation Protection. The basic requirements for the performance of ALARA design reviews are presented in the Hanford Site Radiological Control Manual (HSRCM). The HSRCM has established trigger levels requiring radiological reviews of non-routine or complex work activities. These requirements are implemented in site procedures HNF-PRO-1622 and 1623. HNF-PRO-1622 Radiological Design Review Process requires that ''radiological design reviews [be performed] of new facilities and equipment and modifications of existing facilities and equipment''. In addition, HNF-PRO-1623 Radiological Work Planning Process requires a formal ALARA Review for planned activities that are estimated to exceed 1 person-rem total Dose Equivalent (DE). The purpose of this review is to validate that the original design for the PFP Cementation Process ensures that the principles of ALARA (As Low As Reasonably Achievable) were included in the original project design. That is, that the design and operation of existing Cementation Process equipment and processes allows for the minimization of personnel exposure in its operation, maintenance and decommissioning and that the generation of radioactive waste is kept to a minimum.

DAYLEY, L.

2000-06-14

93

[Fiber emissions from weathered asbestos cement products. 2. Physical-chemical properties of liberated asbestos fibers].  

PubMed

It could be already shown that fibrous particulates can be emitted from weathered and corroded surfaces of asbestos-cement-(AC)-products and that these fibers increase the total ambient air concentration after having been dispersed in the atmosphere. In this investigation we studied the influence of the polluted atmosphere on physical and chemical properties of asbestos fibers in the corroded surface layer. It was found, that in a part of these asbestos fibers the magnesium was partly leached and that the fibers were strongly contaminated by deposited air pollutants. PMID:2547393

Spurny, K; Marfels, H; Boose, C; Weiss, G; Opiela, H; Wulbeck, F J

1989-06-01

94

Study on the hardening mechanism of cement asphalt binder  

Microsoft Academic Search

The hydration and hardening mechanism of cement asphalt binder (CAB) was studied. The early hydration process, hydration products\\u000a and paste microstructure of CAB made by Portland cement and anionic asphalt emulsion were investigated by calorimetry, X-ray\\u000a diffraction, and environmental scanning electron microscopy. The early hydration process of CAB can be characterized as 5\\u000a stages similar to those of Portland cement.

JinBo Yang; PeiYu Yan; XiangMing Kong; Xiang Li

2010-01-01

95

Silicon production process evaluations  

NASA Astrophysics Data System (ADS)

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

1982-05-01

96

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

SciTech Connect

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

Hill, J.; Sharp, J.H

2003-01-01

97

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

98

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

PubMed

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

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

2007-07-18

99

Environmental assessment of sewage sludge as secondary raw material in cement production – A case study in China  

Microsoft Academic Search

A life cycle assessment was carried out to estimate the environmental impact of sewage sludge as secondary raw material in cement production. To confirm and add credibility to the study, uncertainty analysis was conducted. Results showed the impact generated from respiratory inorganics, terrestrial ecotoxicity, global warming, and non-renewable energy categories had an important contribution to overall environmental impact, due to

Jinglan Hong; Xiangzhi Li

2011-01-01

100

Energy Savings by Improved Control of the Finish Grinding Process in Cement Manufacture: Final Report, January 1, 1985-December 31, 1986.  

National Technical Information Service (NTIS)

Conventional closed-circuit ball mill systems for the finish grinding of portland cement produces product particle size distributions (PSDs) which indicate poor reduction of topsize and excessive production of fines. Optimization of ball mill systems shou...

S. J. Weiss S. W. Tresouthick

1987-01-01

101

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

SciTech Connect

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

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

2007-12-15

102

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

EPA Science Inventory

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

103

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

EPA Science Inventory

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

104

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

EPA Science Inventory

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

105

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

National Technical Information Service (NTIS)

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

K. J. Law E. P. Luther

1997-01-01

106

Optimization of copper cementation process by iron using central composite design experiments  

Microsoft Academic Search

In this study, the effects of various experimental parameters on the cementation yield of copper by iron were investigated statistically. A statistical experimental design based on the second-order central composite rotatable design (CCRD) was planned fixing the cementation period at 2h. The experimental design was done at five levels of the operating parameters which were the initial copper concentration, temperature,

W. Djoudi; F. Aissani-Benissad; S. Bourouina-Bacha

2007-01-01

107

Freshwater-phreatic calcite cementation, Schooner Cays, Bahamas  

SciTech Connect

Freshwater-phreatic calcite cementation is an active process on 700 and 2700 yr-old ooid-sand islands in the Schooner Cays, Bahamas. Cement fabrics and textures indicate a general, four-stage model of pore infilling. (1) The precipitation of isolated, decimicron-sized, rhombohedrons of calcite on grain surfaces forms an incipient circumgranular cement. (2) Continued precipitation enlarges crystal sizes and forms new rhombohedral crystals, resulting in a continuous circumgranular rim of cement. (3) Additional cementation quickly masks the circumgranular fabric, producing a partial pore-filling mosaic. (4) The remaining pore space is occluded with a mosaic of calcite cement. Petrographic evidence for the earlier circumgranular rim of cement is not necessarily apparent after the last stage of cementation. Empty pores and all four stages of phreatic-zone cementation were observed in the diagenetically immature 700 yr-old rocks, but only stages 2 through 4 were observed in the diagenetically more mature 2700 yr-old phreatic zone samples. Cements are distributed homogeneously within each pore at every stage, yet because each pore may proceed through the four stages at different rates, each pore can be at a different stage of infilling. This results in an inhomogeneous distribution of cement between pores during the initial stages of cementation. Recognition of a cement stratigraphy similar to that described here should aid in the identification of freshwater-phreatic diagenesis in ancient carbonate rock sequences. Variability in the amount of freshwater-phreatic cement between pores should be expected and not interpreted as the product of different paragenetic sequences.

Budd, D.A.

1985-02-01

108

Alkaline stability of cellulose ethers and impact of their degradation products on cement hydration  

Microsoft Academic Search

Cellulose ethers are polymers frequently introduced into mortar formulations. This study allows to assess the potential role of cellulose ethers degradation on the alteration of the cement hydration kinetics. A retardation mechanism based on the calcium binding capacity of chelates is often proposed to describe the effects of some polysaccharides (e.g. sugars) on cement hydration. The alkaline stability of cellulose

J. Pourchez; A. Govin; P. Grosseau; R. Guyonnet; B. Guilhot; B. Ruot

2006-01-01

109

Biorefineries – Multi Product Processes  

Microsoft Academic Search

The development of biorefineries represents the key for access to an integrated production of food, feed, chemicals, materials, goods, and fuels of the future?[1]. Biorefineries combine the necessary technologies of the biogenic raw materials with those of intermediates and final products. The main focus is directed at the precursors carbohydrates, lignin, oils, and proteins and the combination between biotechnological and

B. Kamm; M. Kamm

110

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.

111

Performance of lime-soda sinter process residue in the manufacture of sulfate-resistant portland cement  

SciTech Connect

The residue from the Ames Lime-Soda Sinter Process for recovering alumina from power plant fly ash consists largely of dicalcium silicate and shows promise as a raw material for the manufacture of a low-alumina, sulfate-resistant portland cement. A laboratory burnability study has been conducted to determine the best way to utilize this raw material from both clinker quality and economic perspectives. These tests are essential when a new material, such as the lime-sinter process residue, it to be considered as a possible cement raw material. The amount of unreacted lime can be used as a measure of the reactivity of a raw mix by indicating the extent to which the cement reactions have progressed. Conditions of residence time and temperature used for the burnability tests were chosen to simulate actual kiln operation. A factorial experimental design made of the parameters of burning temperature, lime content, and lumina (flux) content. Preliminary results from this study indicate that a raw mix made from the sinter residue yields a satisfactory cement.

Chesley, J.A.; Burnet, G.

1986-04-25

112

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

113

Silicon Production Process Evaluations.  

National Technical Information Service (NTIS)

The chemical engineering analysis of the preliminary process design of a process for producing solar cell grade silicon from dichlorosilane is presented. A plant to produce 1,000 MT/yr of silicon is analyzed. Progress and status for the plant design are r...

1981-01-01

114

The processing, mechanical properties and bioactivity of strontium based glass polyalkenoate cements  

Microsoft Academic Search

The suitability of zinc-based glass polyalkenoate cements (GPCs) for use in orthopaedics can be improved by the substitution\\u000a of strontium into the glass phase which should impart improved radiopacity and bone forming properties to the cements without\\u000a retarding strength. The purpose of this research was to produce novel GPCs based on calcium–strontium–zinc-silicate glasses\\u000a and to evaluate their mechanical properties and

Anthony Wren; Daniel Boyd; M. R. Towler

2008-01-01

115

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

SciTech Connect

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

Lu, Hongyou; Masanet, Eric; Price, Lynn

2009-05-29

116

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

SciTech Connect

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

Wu Kai [Key Laboratory of Advanced Civil Engineering Materials, Tongji University, Ministry of Education, 4800 Caoan Road, Shanghai 201804 (China); Magnel Laboratory for Concrete Research, Department of Structure Engineering, Ghent University, Technologiepark-Zwijinaarde 904, Ghent 9052 (Belgium); Shi Huisheng, E-mail: shs@tongji.edu.cn [Key Laboratory of Advanced Civil Engineering Materials, Tongji University, Ministry of Education, 4800 Caoan Road, Shanghai 201804 (China); Guo Xiaolu [Key Laboratory of Advanced Civil Engineering Materials, Tongji University, Ministry of Education, 4800 Caoan Road, Shanghai 201804 (China)

2011-09-15

117

Comparison of glass ionomer cement and incus interposition in reconstruction of incus long process defects.  

PubMed

The ossicles may be affected through the mass effect of the pathological tissue in chronic otitis media. Ossicular reconstruction may be accomplished using the patients' own ossicles or with alloplastic materials. Glass ionomer ossiculoplasty is a fast, efficient, safe and cost-effective method and it has been used more frequently in recent years. Forty-six patients who had surgery for chronic otitis media were included in this study. All patients had an incus long process defect and a normal stapes superstructure. Ossicular reconstruction was performed using glass ionomer cement (GIC) (Ketac-Cem, Espe Dental AG, Seefeld, Germany) in 23 patients (group 1), while incus interposition was performed in other 23 patients (group 2). Preoperative and postoperative air pure tone averages of the group 1 patients were 42.8 and 35.2 dB, respectively (p < 0.01). These values were 42.9 and 34.5 dB in group 2 (p < 0.01). Two groups were similar with respect to postoperative hearing gain (p > 0.05). The air bone gap of group 1 was 27 dB preoperatively and 20.7 dB postoperatively. These values were 28.7 and 20.2 dB, respectively, in group 2. The closure of air bone gap was statistically significant in both the groups (p < 0.01, p < 0.01). The comparison of the mean gains of the air bone gap revealed no difference between the groups (p > 0.05). In conclusion, the use of both GIC ossiculoplasty and incus interposition are efficient methods for reconstruction of incus long process and one is not superior to the other. A larger study population may be useful for comparison of these methods. PMID:21340562

Dere, Huseyin; Ozdogan, Fatih; Ozcan, K Murat; Selcuk, Adin; Ozcan, Ibrahim; Gokturk, Gokhan

2011-02-22

118

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

SciTech Connect

The majority of solidification/stabilization systems for low-level radioactive waste (LLW) and mixed waste, both in the commercial sector and at Department of Energy (DOE) facilities, utilize hydraulic cement (such as portland cement) to encapsulate waste materials and yield a monolithic solid waste form for disposal. A new and innovative process utilizing modified sulfur cement developed by the US Bureau of Mines has been applied at Brookhaven National Laboratory (BNL) for the encapsulation of many of these problem'' wastes. Modified sulfur cement is a thermoplastic material, and as such, it can be heated above it's melting point (120{degree}C), combined with dry waste products to form a homogeneous mixture, and cooled to form a monolithic solid product. Under sponsorship of the DOE, research and development efforts at BNL have successfully applied the modified sulfur cement process for treatment of a range of LLWs including sodium sulfate salts, boric acid salts, and incinerator bottom ash and for mixed waste contaminated incinerator fly ash. Process development studies were conducted to determine optimal waste loadings for each waste type. Property evaluation studies were conducted to test waste form behavior under disposal conditions by applying relevant performance testing criteria established by the Nuclear Regulatory Commission (for LLW) and the Environmental Protection Agency (for hazardous wastes). Based on both processing and performance considerations, significantly greater waste loadings were achieved using modified sulfur cement when compared with hydraulic cement. Technology demonstration of the modified sulfur cement encapsulation system using production-scale equipment is scheduled for FY 1991. 12 refs., 8 figs., 3 tabs.

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

1990-01-01

119

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

120

Process of making oxidation products  

Microsoft Academic Search

This patent describes a process of making oxidation products from oxidizable matter by combustion in an internal-combustion engine. The process consists of admitting said oxidizable matter and an amount of an oxidizing agent insufficient for its complete combustion, into the combustion chambers of said engine, and igniting the mixture. This causes combustion to occur therein with the formation of incompletely

Odell

1933-01-01

121

Calcium silicate cement sorbent for HâS removal and improved gasification processes. Final report  

Microsoft Academic Search

Based on the studies performed on the agglomerated cement sorbent (ACS) pellet for in-situ desulfurization of gases and for improved gasification, in low and medium Btu fluidized bed coal gasifier (FBG) systems, the following conclusions can be drawn: (1) The pelletization method by a drum pelletizer is a good way of agglomerating large sized (>20 US mesh) ACS pellets having

H. J. Yoo; M. Steinberg

1983-01-01

122

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

Microsoft Academic Search

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

CAIJUN SHI; ROGER SPENCE

2004-01-01

123

Waste conversion process and products  

US Patent & Trademark Office Database

A process is disclosed for time production of fuel pellets or briquettes from sewage sludge solids and municipal solid waste with minimal drying requirements. In one of its more specific aspects, this invention relates to a solid pelleted or briquetted fuel product consisting essentially of sewage sludge solids, waste paper and/or refuse derived fuel, and crushed coal, and to its method of preparation. In still another of its specific aspects, this invention relates to a method for the production of fuel gases from sewage sludge solids and cellulosic wastes.

1995-07-11

124

Processing of coal liquefaction products  

SciTech Connect

A process is disclosed for removing undesirable elements, e.g. Nitrogen, sulfur, oxygen, from the light organic liquid product derived from a solvent refined coal liquefaction process, while preserving octane number. The steps of (1) subjecting the light liquids to an ion-exchange resin treatment and (2) contacting the resulting ion-exchanged liquids with a zeolite acting as an adsorbent under specified conditions of space velocity, temperature and pressure.

Garwood, W.E.; Voltz, S.E.; Wu, E.L.

1982-02-02

125

Prediction of cement strength: analysis and implementation in process quality control  

NASA Astrophysics Data System (ADS)

The main purpose of the present article is to develop mathematical models predicting cement strength at 28 days based on early strength as well as on physical and chemical characteristics of cement types investigated. In parallel, a relatively extended analysis of a series of existing models is performed. Static and movable time horizon models have been built and implemented to real industrial conditions for the long-term. These tools are applied in conjunction with a proportional-integral controller regulating 28 days strength around a target. Performance of the models is investigated using typical statistical analysis. The implementation of these techniques in daily quality control has been demonstrated as an important factor of quality improvement by maintaining a low variance of 28 days strength.

Tsamatsoulis, Dimitris

2012-12-01

126

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

SciTech Connect

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

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

2005-05-01

127

Extruded Fiber Reinforced Cement Pressure Pipe  

Microsoft Academic Search

Extrusion is a plastic-forming method that is suitable not only for flat shapes, but also for structural shapes, such as I-sections, channels, pipes, and hollow and solid tubes. The advantage of introducing extrusion into cement product processing is that the materials are formed under high shear and compressive forces resulting in composites with improved performance. This article presents research results

Corina Aldea; Shashi Marikunte; Surendra P Shah

1998-01-01

128

Influence of cement kiln dust substitution on the mechanical properties of concrete  

SciTech Connect

Large quantities of cement kiln dust (CKD) are produced during the manufacture of cement clinker by the dry process. The technical and economical problems that arise for the semi-manufacture of raw materials used, energy and transportation of dust from the plant to outside, as well as the severe pollution to the surrounding atmosphere show the necessity of utilizing cement dust as one of the main objectives of the investigation. The cement dust contains a mixture of raw feed as well as calcined materials with some volatile salts. The aim of the present work is to study the effect of cement dust substitution instead of ordinary Portland cement (OPC), blast furnace slag cement (BFSC), and sulfate resistance cement (SRC) on the mechanical properties of some concrete mixes containing them, and also, to determine the optimum quantity of CKD which could be recycled in the manufacture of these types of cements. Useful conclusions and recommendations concerning the use of different amounts of CKD in the production of some blended cements as a partial substitution from different types of cements were obtained.

Shoaib, M.M.; Balaha, M.M.; Abdel-Rahman, A.G.

2000-03-01

129

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

130

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

131

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

132

(31)P Solid-State NMR study of the chemical setting process of a dual-paste injectable brushite cements.  

PubMed

The composition and evolution of a brushite-type calcium phosphate cement was investigated by Solid-State NMR and X-ray during the setting process. The cement is obtained by mixing beta-tricalcium phosphate [Ca(3)(PO(4))(2), beta-TCP] and monocalcium phosphate monohydrate [Ca(H(2)PO(4))(2).H(2)O, MCPM] in presence of water, with formation of dicalcium phosphate dihydrate or brushite [CaHPO(2).2H(2)O, DCPD]. Analysis of the initial beta-TCP paste has shown the presence of beta-calcium pyrophosphate [Ca(2)P(2)O(7), beta-CPy] and that of the initial MCPM a mixture of MCPM and dicalcium phosphate [CaHPO(4), DCP]. Follow-up of the chemical composition by (31)P Solid-State NMR enables to show that the chemical setting process appeared to reach an end after 20 min. The constant composition observed at the end of the process was similarly determined. PMID:19365821

Legrand, A P; Sfihi, H; Lequeux, N; Lemaître, J

2009-10-01

133

Energy Efficiency Improvement Opportunities for the Cement Industry  

SciTech Connect

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

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

2008-01-31

134

[Fiber emissions from weathered asbestos cement products. 1. Fiber release in ambient air].  

PubMed

Emissions of fibrous aerosols were measured on buildings with weathered and corroded asbestos-cement-plates (roofing and facade shingles) by means of an already published equipment and procedure. The measured emission factors for asbestos fibers longer than 5 microns were in the range of 10(6) to 10(8) fibers/m2.h. They depended on the type of the AC-plates as well as on their age and corrosion intensity. PMID:2757737

Spurny, K; Marfels, H; Boose, C; Weiss, G; Opiela, H; Wulbeck, F J

1989-05-01

135

The mechanical properties of bone cement as controlled by processing technique: a critical review of the literature  

Microsoft Academic Search

Acrylic bone cement has been used with reasonable clinical success in total joint arthroplasties since the mid 1950's when Charnely first instituted its use. The mechanical properties of bone cement are crucial for determining the success or failure of total joint replacements because bone cement is the weakest mechanical link in such a construction and is likely to be a

Benjamin R. Furman; Subrata Saha

1997-01-01

136

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

137

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

Microsoft Academic Search

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

Naoto Koshizaki

1988-01-01

138

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

139

Commitment to the fully-automated cement laboratory concept: a cement industry trend whose time has come  

Microsoft Academic Search

In the modern cement plant, there is the challenge to balance production efficiency and quality to meet internal and international requirements for standards. Focus is concentrated on the process, rather than the individual job units. Defined in this way, a process is a sequence of activities which provide value and quality to meet production goals. At most innovative companies, the

X. Dupont-Wavrin; M. C. Mound

1997-01-01

140

Global Cement Industry: Competitive and Institutional Dimensions  

Microsoft Academic Search

The cement industry is a capital intensive, energy consuming, and vital industry for sustaining infrastructure of nations. The international cement market –while constituting a small share of world industry output—has been growing at an increasing rate relative to local production in recent years. Attempts to protect the environment in developed countries –especially Europe—have caused cement production plants to shift to

Tarek Selim; Ahmed Salem

2010-01-01

141

Curricular Mapping: Process and Product  

PubMed Central

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

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

2008-01-01

142

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

143

Zeolite-Hydraulic Cement Containment Medium.  

National Technical Information Service (NTIS)

The invention generally relates to a zeolite-hydraulic cement containment medium for hazardous wastes. In particular, the invention relates to a process for preparing a zeolite-portland cement containment medium from a paste prepared by mixing zeolite in ...

P. M. Brown M. A. Maginnis C. R. Furlong M. G. Bakker G. L. Turner

1994-01-01

144

Properties and hydration of blended cements with steelmaking slag  

SciTech Connect

The present research study investigates the properties and hydration of blended cements with steelmaking slag, a by-product of the conversion process of iron to steel. For this purpose, a reference sample and three cements containing up to 45% w/w steel slag were tested. The steel slag fraction used was the '0-5 mm', due to its high content in calcium silicate phases. Initial and final setting time, standard consistency, flow of normal mortar, autoclave expansion and compressive strength at 2, 7, 28 and 90 days were measured. The hydrated products were identified by X-ray diffraction while the non-evaporable water was determined by TGA. The microstructure of the hardened cement pastes and their morphological characteristics were examined by scanning electron microscopy. It is concluded that slag can be used in the production of composite cements of the strength classes 42.5 and 32.5 of EN 197-1. In addition, the slag cements present satisfactory physical properties. The steel slag slows down the hydration of the blended cements, due to the morphology of contained C{sub 2}S and its low content in calcium silicates.

Kourounis, S. [National Technical University of Athens, School of Chemical Engineering, Laboratory of Analytical and Inorganic Chemistry, 9 Heroon Polytechniou St, 15773 Athens (Greece); Tsivilis, S. [National Technical University of Athens, School of Chemical Engineering, Laboratory of Analytical and Inorganic Chemistry, 9 Heroon Polytechniou St, 15773 Athens (Greece)]. E-mail: stsiv@central.ntua.gr; Tsakiridis, P.E. [National Technical University of Athens, School of Mining and Metallurgical Engineering, Laboratory of Physical Metallurgy, 9 Heroon Polytechniou St, 15780 Athens (Greece); Papadimitriou, G.D. [National Technical University of Athens, School of Mining and Metallurgical Engineering, Laboratory of Physical Metallurgy, 9 Heroon Polytechniou St, 15780 Athens (Greece); Tsibouki, Z. [Hellenic Cement Research Center Ltd, Heracles Group, 15 K. Pateli, 14123, Lykovrissi, Athens (Greece)

2007-06-15

145

Fuzzy Decision Modeling of Product Development Processes  

Microsoft Academic Search

\\u000a Product development has become a focus of competition in many industries. Due to decreasing product life cycle, it is important\\u000a to reduce the time and cost of product development. The product development process includes six main phases: product planning,\\u000a concept development, system-level design, detailed design, testing and refinement, and production ramp-up [34]. Concept development process consists of four stages: identifying

Juite Wang; Andrew Kusiak

146

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

147

Cellular automata modelling of the cementation process of the Turin (Italy) subsoil conglomerate (``ceppo''),based on a three-dimensional geological model of the city subsoil.  

NASA Astrophysics Data System (ADS)

The Turin (Italy) subsoil is mainly made up by alluvial gravels and sands (Pleistocene), characterised by high cementation degree variability, covered by a thin thickness of loess. These alluvial sediments, of about 40 m deep, overlay lacustrine clays (Villafranchiano), locally heteropic with marine sandstones (Pliocene). The reconstruction of the areal distribution of cementation phenomena of the Turin urban subsoil is of fundamental importance within the context of planning and carrying out works in the city subsoil, as well as for preliminary evaluating the stability of such underground works. Moreover, analyses of spatial distribution of soil cementation could be usefully applied for estimating the propagation of waste-polluted fluids, and for reducing either the natural or human-induced risk, related to the overworking of urban area subsoils. The development of mathematical models commonly needs to deal with several interacting physical and chemical phenomena. A deterministic Cellular Automata (CA) model for the evaluation of cementation processes in the conglomerates of the Turin urban subsoil has recently been developed, by using a three-dimensional geological model of the city subsoil based on boreholes data. The model is able to simulate the spatial distribution of the cementation process in the studied area: it has been derived from two pre-existing CA models, i.e. SCAVATU and CABOTO. Geological, mineralogical-petrographic and sedimentological studies of the soil cementation, and a chemical-physical study of the carbonatic equilibria, have first been carried out. These studies pointed out the presence of meniscus cements (which suggest a meteoric diagenesis) and gave fundamental cues for the development of base hypothesis on the genesis of cementation in the considered area. A macroscopic Cellular Automata model has accordingly been developed, in order to simulate the principal phenomena which take place during the cementation process. The model has a ''layered structure'', composed of the following three layers: 1) the first quantitatively describes pluviometric events in the Turin area. The global amount of rain is subdivided into ''run-off'' and ''infiltration'', by using the c.i.p. value. This layer concerns only the space region in which the run-off occurs: such cells have been classified as ''A'' type. 2) the second layer describes the fluid flow of ''water'' through the soil (i.e. loess and conglomerate). It concerns the space region of the Turin subsoil: such cells have been classified as ''B'' type. 3) the third layer describes the chemical-physical phenomena of ''solute transport'', ''diffusion and chemical reactions of dissolution'', and ''precipitation of calcium carbonate''. Inside the above mentioned cells, the chemical-physical phenomena are allowed to occur. Owing to their high complexity, the global phenomena under consideration have been decomposed into ''elementary'' processes (run-off, infiltration and chemical-physical reactions) and properly translated into CA local rules. The model, opportunely implemented in a parallel computing environment, allows to simulate the process of cementation of the Turin urban subsoil: as mentioned above, it could be therefore usefully applied for mitigating natural and man-induced hazards in the study area.

Bello, S.; de Rienzo, F.; Nardi, G.

2003-04-01

148

Characterization of spatial impact of particles emitted from a cement material production facility on outdoor particle deposition in the surrounding community.  

PubMed

The objective of this study was to estimate the contribution of a facility that processes steel production slag into raw material for cement production to local outdoor particle deposition in Camden, NJ. A dry deposition sampler that can house four 37-mm quartz fiber filters was developed and used for the collection of atmospheric particle deposits. Two rounds of particle collection (3-4 weeks each) were conducted in 8-11 locations 200-800 m downwind of the facility. Background samples were concurrently collected in a remote area located -2 km upwind from the facility. In addition, duplicate surface wipe samples were collected side-by-side from each of the 13 locations within the same sampling area during the first deposition sampling period. One composite source material sample was also collected from a pile stored in the facility. Both the bulk of the source material and the < 38 microm fraction subsample were analyzed to obtain the elemental source profile. The particle deposition flux in the study area was higher (24-83 mg/m2 x day) than at the background sites (13-17 mg/m2day). The concentration of Ca, a major element in the cement source production material, was found to exponentially decrease with increasing downwind distance from the facility (P < 0.05). The ratio of Ca/Al, an indicator of Ca enrichment due to anthropogenic sources in a given sample, showed a similar trend. These observations suggest a significant contribution of the facility to the local particle deposition. The contribution of the facility to outdoor deposited particle mass was further estimated by three independent models using the measurements obtained from this study. The estimated contributions to particle deposition in the study area were 1.8-7.4% from the regression analysis of the Ca concentration in particle deposition samples against the distance from the facility, 0-11% from the U.S. Environmental Protection Agency (EPA) Chemical Mass Balance (CMB) source-receptor model, and 7.6-13% from the EPA Industrial Source Complex Short Term (ISCST3) dispersion model using the particle-size-adjusted permit-based emissions estimates. PMID:22070034

Yu, Chang Ho; Fan, Zhihua; McCandlish, Elizabeth; Stern, Alan H; Lioy, Paul J

2011-10-01

149

Accelerating the product design process  

Microsoft Academic Search

Summary form only given. It is pointed out that, whether one is developing a simple or a complex product, the product design and development cycle can be accelerated by adopting an approach that stresses planning, close teamwork, superior communication, realistic evaluation procedures, and full use of available tools and resources. Planning begins with a clear definition of the product rationale,

R. G. Ollila; D. R. Forry; D. W. Caudy

1991-01-01

150

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

PubMed

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

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

2006-01-25

151

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

152

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

National Technical Information Service (NTIS)

China's cement industry, which produced 1,388 million metric tons (Mt) of cement in 2008, accounts for almost half of the world's total cement production. Nearly 40% of China's cement production is from relatively obsolete vertical shaft kiln (VSK) cement...

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

2009-01-01

153

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

National Technical Information Service (NTIS)

China's cement industry, which produced 1,388 million metric tons (Mt) of cement in 2008, accounts for almost half of the world's total cement production. Nearly 40% of China's cement production is from relatively obsolete vertical shaft kiln (VSK) cement...

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

2009-01-01

154

The effect of excessive steam curing on Portland composite cement concrete  

Microsoft Academic Search

Steam curing at atmospheric pressure is an important technique for obtaining high early strength values in precast concrete production. Cement type, as well as curing period and temperature, is an important parameter in the steam-curing process. PC42.5 is the type of cement that is most commonly used in Turkish precast concrete plants. Its behavior is well known. Nowadays, the production

Selcuk Türkel; Volkan Alabas

2005-01-01

155

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

156

Study of Barnacle Cement.  

National Technical Information Service (NTIS)

Gross anatomical studies were done on the giant barnacle Balanus nubilis. This work was aimed at finding the site of cement production and its internal flow path. The internal flow path is a tubular network in the basal mass that communicates with the rad...

D. Lockhart K. Walker T. King R. Keller N. F. Cardarelli

1968-01-01

157

Basic studies on hydroxy apatite cement: I. Setting reaction.  

PubMed

Self-setting cements, alpha D-Cement and alpha DT-Cement, were prepared. They consisted of only the calcium phosphates alpha-TCP, TTCP and DCPA. These cements reacted and hardened in a moist environment at 37 degrees C. The powder X-ray diffraction patterns were taken to examine the conversion of their reactions as a function of time. The cements reacted and produced hydroxyapatite. The optimum powder/liquid ratio of alpha D-Cement was 2.0 and that of alpha DT-Cement was 1.8. The initial setting time of alpha D-Cement was 87.5 m and that of alpha DT-Cement was 107.5 m. The component and the product of these cements are calcium phosphates which are the putative minerals in teeth and bones. Therefore, these cements are useful for oral surgery as bone-filling materials. PMID:9680764

Fukase, Y; Wada, S; Uehara, H; Terakado, M; Sato, H; Nishiyama, M

1998-06-01

158

Product development process intelligent analysis and improvement  

Microsoft Academic Search

Product development process analysis and improvement are very important to enterprises, but most Product Data Management (PDM) systems are not good at them. This paper presents a method that integrates Design Structure Matrix (DSM), Genetic Algorithm (GA) and Expert System (ES) techniques to intelligently analyze and improve the product development process managed by PDM systems. Based on DSM representation, GA

Yao Yong; Xiong Guangleng; Fan Wenhui; Fan Xiaodong

2004-01-01

159

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

160

Lubricant production process with product viscosity control  

SciTech Connect

This patent describes a process for producing a 140 and higher V.I., low pour point lubricant from a deoiled slack wax feed containing 10 ppm nitrogen, and more than 0.01 wt% sulfur. It comprises partially dewaxing the feed in an initial catalytic dewaxing step by contacting the feed under dewaxing conditions of elevated temperature and pressure in the presence of hydrogen with a dewaxing catalyst comprising zeolite beta and a hydrogenation- dehydrogenation component, to effect a partial removal of the waxy components by isomerization of the waxy paraffinic components to less waxy iso-paraffinic components, to produce a partially dewaxed effluent, subjecting the partially dewaxed effluent to a selective dewaxing operation to effect a further removal of waxy components to produce a dewaxed lubricant fraction, and subjecting the dewaxed lubricant fraction to treatment with an organic peroxide with an amount of organic peroxide equal to 1 to 50 wt% of the dewaxed lubricant fraction to increase the viscosity of the fraction.

Garwood, W.E.; Le, Q.N.; Wong, S.S.

1991-08-06

161

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

162

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

163

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

164

The effect of the proportion of thin film transistor–liquid crystal display (TFT–LCD) optical waste glass as a partial substitute for cement in cement mortar  

Microsoft Academic Search

In the high-tech industry in Taiwan, the use of LCD glass products have increased significantly in recent years, which produces a large amount of waste LCD glass during the manufacturing process. This study is based on the 0.485 w\\/b and 10%, 20%, 30%, 40%, and 50% substitution amount to discuss the effect of glass powder proportions on cement in cement

Her-Yung Wang

2011-01-01

165

Process for Impregnating a Concrete or Cement Body with a Polymeric Material.  

National Technical Information Service (NTIS)

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 contai...

A. J. Mattus R. D. Spence

1988-01-01

166

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

Microsoft Academic Search

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

A Maimoni

1982-01-01

167

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

SciTech Connect

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

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

2010-10-15

168

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

169

Immobilisation of MTR Waste in Cement (Product Evaluation). Annual Report March 1985.  

National Technical Information Service (NTIS)

This report describes work performed at Winfrith under the UKAEA's research and development programme on radioactive waste management. The work carried out during April 1984 to March 1985 on the evaluation of laboratory and 200 dm sup 3 scale products of ...

C. G. Howard D. L. G. Smith J. R. A. Williams

1986-01-01

170

Method of the cementing of material  

SciTech Connect

Invention relates to woodworking industry and concerns method of cementing of materials of foam plastic with duralumin, glued plywood, etc. Known methods of cementing of materials by effect of electromagnetic field of superhigh frequencies are unproductive and do not make it possible to cement parts on the plane. Target of invention - acceleration of process of cementing of planar, including of complex configuration, parts and assemblies from wood, foam plastic, duralumin, glued plywood and other materials. For this material is cemented under the effect of directed electromagnetic field of superhigh frequency in the range 01-50 GHz, the specific power of 0.5-15 W/cm3.

Konovalov, Y.G.; Shutov, G.M.; Khanenya, G.P.; Dyatko, E.K.; Buben, K.K.

1990-10-30

171

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

172

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

DOEpatents

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

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

1988-05-04

173

Process for the production of ceramic tiles  

US Patent & Trademark Office Database

The present invention is directed to an improved process for the production of ceramic tiles using industrial wastes. The invention particularly relates to an improved process for the production of ceramic tiles using industrial wastes such as iron ore slime, fly ash and blast furnace slag.

2004-06-01

174

Integrated system and process for bioproduct production  

US Patent & Trademark Office Database

Processes and systems for production of bioproducts such as biofuels are provided. The bioproduct production processes and systems utilize pretreatment of a carbohydrate-containing feedstock to produce soluble sugar molecules and continuous conversion of the pretreated feedstock to a bioproduct by an immobilized fermenting microorganism.

Walther; David C. (Oakland, CA); Meerman; Hendrik J. (Scotts Valley, CA); Burns-Guydish; Stacy M. (Campbell, CA); Wilson; Richard W. (Palo Alto, CA); Hogg; Eamon T. (Decatur, GA); Luli; Gregory W. (San Diego, CA); Eckert; Robert (Auburn, WA)

2013-07-30

175

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

176

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

2010-08-17

177

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

178

First seconds in a building's life-in situ synchrotron X-ray diffraction study of cement hydration on the millisecond timescale.  

PubMed

Setting cement: highly dynamic hydration processes that occur during the first seconds of cement hydration were studied by time-resolved synchrotron X-ray diffraction. Polycarboxylate ether additives were found to influence the formation of the initial crystalline hydration products on a molecular level. PMID:22492533

Schlegel, Moritz-Caspar; Sarfraz, Adnan; Müller, Urs; Panne, Ulrich; Emmerling, Franziska

2012-04-11

179

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

180

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

SciTech Connect

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

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

1980-04-18

181

Stabilization\\/solidification of sludges containing heavy metals by using cement and waste pozzolans  

Microsoft Academic Search

The experiments were carried out with 16 mixtures of cement, fly ash, slag, and shell?lime; each of these mixtures was blended with water. The research also evaluated an optimal S\\/S process designed to encapsulate inorganic hazardous wastes (heavy metals) within cement, pozzolanic materials, and the accelerators which are Na2S, NH4Cl, FeSO4, and water glass, thereby creating a non?hazardous product. Characteristics

1999-01-01

182

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

PubMed Central

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

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

2005-01-01

183

Process for recovering forest product plant wastes  

Microsoft Academic Search

A process for converting the wood wastes produced at lumber, pulp, and paper mills into steam and activated carbon is discussed. The steam may be used for processing the products or for conversion into electric power. The activated carbon can be used to filter the mill effluents. The process reduces air and water pollution to low levels which meet Federal

Thompson; R. E. S

1974-01-01

184

The learning of counseling: Process not product  

Microsoft Academic Search

This paper questions the more traditional content concept of learning, and points out the traditional involvement of the teacher with product and ideas rather than with process and people. It stresses the process and the learning functions of the counselor, and illustrates the process orientation by reference to various poets and novelists. It discusses the problems of the counselor as

Dugald S. Arbuckle

1963-01-01

185

Processes for the production of deashed coal  

Microsoft Academic Search

An improved coal deashing process is described wherein soluble dissolved coal present in the ash concentrate product stream from a critical solvent deashing process can be separated and recovered from the ash concentrate by at least two alternate processing systems. In one such system, the ash concentrate (containing dissolved and undissolved coal) is admixed with suitable organic solubilizing solvent to

R. Baldwin; J. L. Bills

1978-01-01

186

Purification of zinc ammoniacal leaching solution by cementation: Determination of optimum process conditions with experimental design by Taguchi's method  

Microsoft Academic Search

The Taguchi method was used as the experimental design to determine the optimum conditions of purification behavior of the leach solution obtained from ammoniacal ammonium carbonate leaching of nonsulphide zinc ores in Angoran region (Iran). Cementation was performed using zinc dust. The experimental conditions were studied in the range of 25–65°C for reaction temperature (T), one to five series for

J. Moghaddam; R. Sarraf-Mamoory; M. Abdollahy; Y. Yamini

2006-01-01

187

Stromatolites, ooid dunes, hardgrounds, and crusted mud beds, all products of marine cementation and microbial mats in subtidal oceanic mixing zone on eastern margin of Great Bahama Bank  

SciTech Connect

The interisland channels along the eastern margin of the Great Bahamas Bank contain lithified structures that owe their origin to recent marine cementation. This cementation appears to be commonly associated with a complex microbial community of plants and microorganisms living within a bank-margin oceanographic mixing zone. In this region, reversing tidal and wind-driven currents flow up to 3 knots (150 cm/sec) three hours out of each six-hour tidal period. Here, marine-cement crusted, carbonate mud beds are found interbedded within migrating ooid sand bars and dunes and are associated with growing, lithified stromatolites up to 2 m in height. These laminated mud beds are found with thicknesses of up to 1 m in subtidal depths of 4 to 8 m (12 to 25 ft). The muds appear to be homogeneous, but closer examination by SEM and under a microscope reveals they are composed of pelletoid aggregates of needle-shaped aragonite crystals with diameters of up to 50 ..mu... The size of these soft pellets is similar to the smaller grains of ooid sands that are abundant in the area. This size similarity could explain why both the mud beds are found in similar high-energy hydraulic regimes as the ooid sands, but does not suggest how or why the aggregates of pure aragonite needles form. A high production of ooid sand within this bank margin environment permits the formation of natural levees along the margins of tidal channels. The back sides of these levees are being lithified by marine cements to form hardgrounds. Skeletal and ooid sand dunes stabilized by Thallasia in channel bottoms also are becoming lithified. Grapestones form at the distributaries of flood tidal deltas of ooid sand. All of these features have a common attribute: they are continually in contact with the turbulent mixing-zone waters.

Dill, R.F.; Kendall, C.S.C.G.; Steinen, R.P.

1989-03-01

188

The effect of cyanide and lead ions on the cementation rate, stoichiometry and morphology of silver in cementation from cyanide solutions with zinc powder  

Microsoft Academic Search

The cementation of silver on zinc powder from solutions with a wide concentration range of cyanide has been investigated in the absence and presence of lead ions through stirred reactor batch tests and scanning electron microscopy studies on the cementation product. The concentration of cyanide ions affected the morphology of the product, the nature of cementation reaction and the cementation

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

2005-01-01

189

PRODUCTION OF CARBON PRODUCTS USING A COAL EXTRACTION PROCESS  

SciTech Connect

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

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

2004-08-31

190

Co-firing of refuse-derived fuel (RDF) with natural gas in a cement kiln: Summary of test results  

SciTech Connect

In July of 1986, the Environmental Equipment Corporation, in association with the Portland Cement Association and the Gulf Coast Portland Cement Company, initiated a program to develop and test refuse-derived fuel (RDF) on a commercial scale as a supplemental energy source for the portland cement industry. The objectives of the work performed were to definitely determine the technical and operational limits on the use of RDF, and to develop and test the equipment and systems required by cement plants to use RDF on a full-time commercial basis. Three extended trial burns were completed with satisfactory results at the Gulf Coast Portland Cement Company's plant in Houston, Texas. Prior to these tests, the kiln was normally fired with natural gas to produce clinker by the wet process. During the trial burns, 20%, 30%, and 40%, respectively, of the heat input was supplied by RDF. Each test lasted approximately three days, in all producing 8500 tons of cement while burning 1338 tons of RDF. Analyses of the cement clinker, kiln feed, flue dust, ash, precipitator dust, and cooler dust by an independent testing authority -- the Portland Cement Association -- showed acceptable clinker quality and acceptable environmental data. Although some loss of cement product strength was encountered in the third (i.e., 40% RDF) test, this may have been due to an inadvertent, temporary loss of temperature control.

Reed, J.E.; Conrad, J.L.; Price, C.D.

1983-03-01

191

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

192

Process engineering economics of bioethanol production.  

PubMed

This work presents a review of studies on the process economics of ethanol production from lignocellulosic materials published since 1996. Our objective was to identify the most costly process steps and the impact of various parameters on the final production cost, e.g. plant capacity, raw material cost, and overall product yield, as well as process configuration. The variation in estimated ethanol production cost is considerable, ranging from about 0.13 to 0.81 US$ per liter ethanol. This can be explained to a large extent by actual process differences and variations in the assumptions underlying the techno-economic evaluations. The most important parameters for the economic outcome are the feedstock cost, which varied between 30 and 90 US$ per metric ton in the papers studied, and the plant capacity, which influences the capital cost. To reduce the ethanol production cost it is necessary to reach high ethanol yields, as well as a high ethanol concentration during fermentation, to be able to decrease the energy required for distillation and other downstream process steps. Improved pretreatment methods, enhanced enzymatic hydrolysis with cheaper and more effective enzymes, as well as improved fermentation systems present major research challenges if we are to make lignocellulose-based ethanol production competitive with sugar- and starch-based ethanol. Process integration, either internally or externally with other types of plants, e.g. heat and power plants, also offers a way of reducing the final ethanol production cost. PMID:17541520

Galbe, Mats; Sassner, Per; Wingren, Anders; Zacchi, Guido

2007-01-01

193

Cost effective energy information system for cement manufacturers  

Microsoft Academic Search

Cement plants worldwide share a multitude of business and operational challenges, ranging from increasing plant availability and production to cutting energy consumption per ton, in addition to taking control of emissions. Over the last 10 years, there have been very significant improvements in the reduction in energy per ton of production in cement manufacturing in some countries; however, cement companies

Fabio Mielli

2012-01-01

194

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

195

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

196

30 CFR 250.1608 - Well casing and cementing.  

Code of Federal Regulations, 2010 CFR

...Second cap rock casing (brine wells), and (vi) Production...lessee shall case and cement all wells with a sufficient number...fluids. Cement composition, placement techniques, and waiting...sufficient magnitude to provide well control during drilling...

2009-07-01

197

30 CFR 250.1608 - Well casing and cementing.  

Code of Federal Regulations, 2010 CFR

...Second cap rock casing (brine wells), and (vi) Production...lessee shall case and cement all wells with a sufficient number...fluids. Cement composition, placement techniques, and waiting...sufficient magnitude to provide well control during drilling...

2010-07-01

198

Mariculture of Bivalves for Processed Meat Products.  

National Technical Information Service (NTIS)

The research investigated the possibility of farming juvenile bivalves and harvesting them to use their meats for processed clam products. Five species were selected for trial cultivation. Mulina lateralis, Amygdalum papyrium, and cyrtopleura costata (ang...

P. Chanley

1984-01-01

199

Product Decision Processes Among Older Adults.  

National Technical Information Service (NTIS)

The goal of the study was to explore and assess consumer information processing problems from the perspective of elderly consumers in order to optimize product choices. Specifically, the investigation attempted to determine how older consumers, as compare...

T. K. Bikson J. D. Goodchilds

1978-01-01

200

Biological hydrogen production; fundamentals and limiting processes  

Microsoft Academic Search

Biological hydrogen production has been known for over a century and research directed at applying this process to a practical means of hydrogen fuel production has been carried out for over a quarter century. The various approaches that have been proposed and investigated are reviewed and critical limiting factors identified. The low energy content of solar irradiation dictates that photosynthetic

Patrick C. Hallenbeck; John R. Benemann

2002-01-01

201

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

202

The nature of CSH in hardened cements  

Microsoft Academic Search

Calcium silicate hydrates (C-S-H) are the main binding phases in all Portland cement-based systems. This paper considers the morphology, composition, and nanostructure of C-S-H in a range of hardened cements. Inner product (Ip) C-S-H present in larger Portland cement grains typically has a fine-scale and homogeneous morphology with pores somewhat under 10 nm in diameter. Ip from larger slag grains

I. G Richardson

1999-01-01

203

Cement Kiln Flue Gas Recovery Scrubber Project  

SciTech Connect

The Cement Kiln Flue Gas Recovery Scrubber Project was a technical success and demonstrated the following: CKD can be used successfully as the sole reagent for removing SO2 from cement kiln flue gas, with removal efficiencies of 90 percent or greater; Removal efficiencies for HCl and VOCs were approximately 98 percent and 70 percent, respectively; Particulate emissions were low, in the range of 0.005 to 0.007 grains/standard cubic foot; The treated CKD sorbent can be recycled to the kiln after its potassium content has been reduced in the scrubber, thereby avoiding the need for landfilling; The process can yield fertilizer-grade K2SO4, a saleable by-product; and Waste heat in the flue gas can provide the energy required for evaporation and crystallization in the by-product recovery operation. The demonstration program established the feasibility of using the Recovery Scrubber{trademark} for desulfurization of flue gas from cement kilns, with generally favorable economics, assuming tipping fees are available for disposal of ash from biomass combustion. The process appears to be suitable for commercial use on any type of cement kiln. EPA has ruled that CKD is a nonhazardous waste, provided the facility meets Performance Standards for the Management of CKD (U.S. Environmental Protection Agency 1999d). Therefore, regulatory drivers for the technology focus more on reduction of air pollutants and pollution prevention, rather than on treating CKD as a hazardous waste. Application of the Recovery Scrubbe{trademark} concept to other waste-disposal operations, where pollution and waste reductions are needed, appears promising.

National Energy Technology Laboratory

2001-11-30

204

Cell culture processes for monoclonal antibody production  

PubMed Central

Animal cell culture technology has advanced significantly over the last few decades and is now generally considered a reliable, robust and relatively mature technology. A range of biotherapeutics are currently synthesized using cell culture methods in large scale manufacturing facilities that produce products for both commercial use and clinical studies. The robust implementation of this technology requires optimization of a number of variables, including (1) cell lines capable of synthesizing the required molecules at high productivities that ensure low operating cost; (2) culture media and bioreactor culture conditions that achieve both the requisite productivity and meet product quality specifications; (3) appropriate on-line and off-line sensors capable of providing information that enhances process control; and (4) good understanding of culture performance at different scales to ensure smooth scale-up. Successful implementation also requires appropriate strategies for process development, scale-up and process characterization and validation that enable robust operation and ensure compliance with current regulations. This review provides an overview of the state-of-the art technology in key aspects of cell culture, e.g., generation of highly productive cell lines and optimization of cell culture process conditions. We also summarize the current thinking on appropriate process development strategies and process advances that might affect process development.

Li, Feng; Vijayasankaran, Natarajan; Shen, Amy (Yijuan); Kiss, Robert

2010-01-01

205

IMPROVED OIL RECOVERY - PRODUCT TO PROCESS  

Microsoft Academic Search

Oil recovery projects designed to improve volumetric sweep have evolved in the past 10 yr from strictly product applications to the use of advanced process technology. The work relates this development by exploring laboratory work and field-wide projects. The results show that the process approach is a major step forward. Unsuccessful waterfloods are usually due to either an extreme permeability

James Mack

1978-01-01

206

Simulation Of Coupled Processes And Product Properties  

NASA Astrophysics Data System (ADS)

The properties of a product result at the end of the production chain. To predict these properties as accurate as feasible every process step has to be described in the exactest way possible. The big challenge for the simulation technique is to realistically depict the actual circumstances in the process chain as well as in the process depth. Usually, simulations are calculated for single process steps of an entire process chain. The aim of recent research is to combine these steps to a complete simulation of a plant even using the calculated results of the previous step as input data for the next one. An useful method to combine simulations and to present the results is the Virtual Reality tool. It offers the possibility to show a three dimensional model of the whole complex plant. Combined with results of logistic simulations the VR-model can visualize the whole production process. For the combination of calculations at several accuracy levels a hierarchical structure was developed. At selectable parts it is possible to go deeper into the process (vertical) and to integrate the above mentioned single process step calculations (horizontal). This horizontal and vertical enlargement of the simulation finally leads to an overall description of the production process of a product. The present manuscript at first describes the new medium Virtual Reality used for representation of complex production facilities in different visualization levels. The hierarchical model matrix with the interfaces is presented. Exemplified for the vertical refinement of the overall model the interaction workpiece/tool in rolling and the link of finite element method with physical material models is shown.

Kopp, Reiner; Hofmann, Oliver; Horst, Christoph; Neumann, Luc; Honnet, Vincent; Plociennik, Christian

2004-06-01

207

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

2008-03-25

208

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

209

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

210

MODELING HYDRATION AND SETTING OF CEMENT  

Microsoft Academic Search

Hydration and setting of cement are complex processes involving chemical reactions and physical interactions which transform a collection of anhydrous grains into a massive hydrated solid. The understanding of all these processes and their synergy needs to develop simpler experimental models than cement which is polyphasic compound. Those experimental models have to be designed in such a way that: (i)

ANDRE NONAT

211

NPOESS Interface Data Processing Segment Product Generation  

NASA Astrophysics Data System (ADS)

The National Oceanic and Atmospheric Administration (NOAA), Department of Defense (DoD), and National Aeronautics and Space Administration (NASA) are jointly acquiring the next-generation weather and environmental satellite system; the National Polar-orbiting Operational Environmental Satellite System (NPOESS). NPOESS replaces the current Polar-orbiting Operational Environmental Satellites (POES) managed by NOAA and the Defense Meteorological Satellite Program (DMSP) managed by the DoD. The NPOESS satellites carry a suite of sensors that collect meteorological, oceanographic, climatological, and solar-geophysical observations of the earth, atmosphere, and space. The NPOESS design allows centralized mission management and delivers high quality environmental products to military, civil and scientific users. The ground data processing segment for NPOESS is the Interface Data Processing Segment (IDPS), developed by Raytheon Intelligence and Information Systems. The IDPS processes NPOESS satellite data to provide environmental data products to NOAA and DoD processing centers operated by the United States government. The IDPS will process environmental data products beginning with the NPOESS Preparatory Project (NPP) and continuing through the lifetime of the NPOESS system. Within the overall NPOESS processing environment, the IDPS must process a data volume nearly 1000 times the size of current systems -- in one-quarter of the time. Further, it must support the calibration, validation, and data quality improvement initiatives of the NPOESS program to ensure the production of atmospheric and environmental products that meet strict requirements for accuracy and precision. This paper will describe the architecture approach that is necessary to meet these challenging, and seemingly exclusive, NPOESS IDPS design requirements, with a focus on the processing relationships required to generate the NPP products.

Grant, K. D.

2009-12-01

212

Renewable hydrogen production for fossil fuel processing  

SciTech Connect

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

Greenbaum, E.

1994-09-01

213

Tires fuel oil field cement manufacturing  

SciTech Connect

In a new process, waste automobile tires added to the fuel mix of gas, coal, and coke help fire kilns to produce API-quality oil field cement. Capital Cement uses this process in its cement-manufacturing plant in San Antonio, in which it also produces construction cement. The tires provide a lower-cost fuel and boost the temperature at a critical stage in the kiln burn process. Also, steel-belted tires add iron content to the mix. According to lab results, tire-burned cement slurries will perform the same as conventionally burned cement slurries. Actual field applications have proven that cement produced by burning tires performs no different than conventionally produced slurries. Capital`s plant uses both dry and wet processes, with separate kilns running both processes at the same time. Cement clinker is partially fired by waste tires in both kiln processes. The tires represent 12% of the fuel consumed by the plant, a number that is expected to increase. Capital burns about 200 tires/hr, or about 1.6 million tires/year.

Caveny, B.; Ashford, D. [Halliburton Energy Services Inc., Duncan, OK (United States); Garcia, J.G. [Capital Cement, San Antonio, TX (United States); Hammack, R. [Halliburton Energy Services Inc., Alice, TX (United States)

1998-08-31

214

CELLULOSE CEMENT COMPOSITE MODIFIED BY POLYMER  

Microsoft Academic Search

The durability of the cellulose-cement composites is a deciding factor to introduce such material in the market. Several researches have been developed aiming to avoid the degradation of vegetable fiber-cement, some using chemically treated fibers and others modifying the matrix. Polymers have been used in concrete and mortar production to increase its durability. The goal of this work is to

L. L. Pimentel; A. L. Beraldo; H. Savastano Jr

215

Dental Silicate Cements: III. Environment and Durability  

Microsoft Academic Search

The nature of the aqueous environment has considerable effect on the durability of dental silicate cements. When free from soluble reaction products, cements show little dissolution in the pH range associated with normal saliva, but are drastically attacked by acids and citrates. These observations suggest that phosphates are important constituents of the gel matrix.

Alan D. Wilson; Reginald F. Batchelor

1968-01-01

216

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

217

Canonical processes of semantically annotated media production  

Microsoft Academic Search

While many multimedia systems allow the association of semantic annotations with media assets, there is no agreed-upon way\\u000a of sharing these among systems. As an initial step within the multimedia community, we identify a small number of fundamental\\u000a processes of media production, which we term canonical processes. We specify their inputs and outputs, but deliberately do\\u000a not specify their inner

Lynda Hardman; Zeljko Obrenovic; Frank Nack; Brigitte Kerhervé; Kurt W. Piersol

2008-01-01

218

The contemporary cement cycle of the United States  

Microsoft Academic Search

A country-level stock and flow model for cement, an important construction material, was developed based on a material flow\\u000a analysis framework. Using this model, the contemporary cement cycle of the United States was constructed by analyzing production,\\u000a import, and export data for different stages of the cement cycle. The United States currently supplies approximately 80% of\\u000a its cement consumption through

Amit Kapur; Hendrik G. van Oss; Gregory Keoleian; Stephen E. Kesler; Alissa Kendall

2009-01-01

219

HST Post-Observation Processes and Products  

Microsoft Academic Search

HST users rely on a complex set of data processing, calibration, and archiving systems to rapidly deliver data products. This paper provides an overview of the systems that cover data receipt through data distribution at STScI. OPUS is responsible for data receipt, telemetry conversion, data evaluation, FITS formatting, calibration, and data quality checking. OPUS generates data files used in astronomical

D. A. Swade

1997-01-01

220

PRODUCT DEVELOPMENT PROCESS MODELING USING ADVANCED SIMULATION  

Microsoft Academic Search

This paper presents a product development process modeling and analysis technique using advanced simulation. The model computes the probability distribution of lead time in a resource -constrained project network where iterations take place among sequential, parallel and overlapped tasks. The model uses the design structure matrix representation to capture the information flows between tasks. In each simulation run, the expected

Soo-Haeng Cho; Steven D. Eppinger

2001-01-01

221

Process for the production of aromatic fuel  

Microsoft Academic Search

A process is described for the production of high octane gasoline component comprising the sequential steps of: A. Cracking carbometallic petroleum oil characterized by a Conradson Carbon content of at least 1.0 wt% and a metals content of at least 4 ppm Nickel Equivalents by weight in a riser cracking zone at cracking conditions in the presence of fluid cracking

R. E. Jr. Yancey; W. P. Jr. Hettinger

1986-01-01

222

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

223

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

224

Effects of DCPD cement chemistry on degradation properties and cytocompatibility: comparison of MCPM/?-TCP and MCPM/HA formulations.  

PubMed

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

2013-02-22

225

Strength properties of refractory mortar with an aluminoborophosphate bond during the cementing of mullite-corundum and fireclay products  

SciTech Connect

A study was conducted of a refractory mortar having a mullite-corundum-zirconia composition with an aluminoborophosphate bond for cementing mullite-corundum blocks, corundum and chamotte (fireclay) bricks. The blocks were made by water casting of mullite containing suspensions with the introduction of finely milled electrocorundum. The bonding capacity of the refractory mortar was assessed by testing bonded specimens for shear and bending strengths. It is shown that the highest shear strengths are possessed by mullite-corundum blocks fired at 1823/sup 0/K. The fired model of block construction made from blocks after drying is shown; the form and design correspond to the planned requirements.

Kliment'eva, V.S.; Filimonova, N.I.; Baranova, T.F.; Grishina, N.E>

1988-09-01

226

Cement kiln temperature measurements using microwave radiometry  

Microsoft Academic Search

Conventional remote temperature measurements in cement kilns and other high-temperature industrial processes are often difficult or impossible because of the presence of dust that disables infrared remote temperature sensors. Microwave radiation is much less scattered by dust. Results from tests of an X-band microwave radiometer and antenna system at a cement kiln show that with calibration, this instrumentation will be

Karl D. Stephan; John A. Pearce; Lingyun Wang; Eric Ryza

2005-01-01

227

Cementation in High-Latitude Dunes.  

National Technical Information Service (NTIS)

Cementing of dune sands by carbonates has not been considered to proceed rapidly in high-latitude regions. This study indicates that dunes along the Scotland coast, however, are actively being cemented by carbonates and that this process is quite widespre...

H. H. Roberts W. Ritchie A. Mather

1973-01-01

228

Improving wellhead performance with programmed cement shortfall  

SciTech Connect

Subsea wellheads can be subjected to extreme external loads when a drilling or production riser remains connected during storm or vessel drive-off conditions. In addition, vortex shedding from high currents and wave action on drilling and production risers can subject the wellhead to high-cycle fatigue loads. These extreme external and high-cycle fatigue loads can cause failure of the wellhead system when a fully cemented annulus between the 30-in. (76-cm) structural conductor pipe and 20-in. (51cm) surface casing is not achieved. This effect of cement shortfall is most damaging when the cement level is just below the wellhead-body/conductor-housing region. Purposefully setting the cement level far below the mudline can be a cost-effective solution to the unintentional cement-shortfall problem.

Britton, J.S.; Henderson, G.

1988-12-01

229

Eliciting information for product modeling using process modeling  

Microsoft Academic Search

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

Ghang Lee; Charles M. Eastman; Rafael Sacks

2007-01-01

230

A Novel Oil Well Cementing Technology Using Natural Fibers  

Microsoft Academic Search

In many industrial processes, the pipeline systems are lined with a protective layer of cement mortar. In petroleum wells, cement slurry is placed in a wellbore to be hardened into an impermeable mass that seals the annulus from fluid flow and protects the casing from corrosion for the life of the well. When uniform linings of neat cement fail in

M. M. Al-Darbi; N. O. Saeed; L. O. Ajijolaiya; M. R. Islam

2006-01-01

231

Multimedia Assessment and Environmental Research Needs of the Cement Industry.  

National Technical Information Service (NTIS)

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

R. F. Smith J. E. Levin

1979-01-01

232

MULTIMEDIA ASSESSMENT AND ENVIRONMENTAL RESEARCH NEEDS OF THE CEMENT INDUSTRY  

EPA Science Inventory

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

233

Barnacle cement: an etchant for stainless steel 316L?  

PubMed

Localized corrosion of stainless steel beneath the barnacle-base is an unsolved issue for the marine industry. In this work, we clearly bring out for the first time the role of the barnacle cement in acting as an etchant, preferentially etching the grain boundaries, and initiating the corrosion process in stainless steel 316L. The investigations include structural characterization of the cement and corroded region, and also chemical characterization of the corrosion products generated beneath the barnacle-base. Structural characterization studies using scanning electron microscopy (SEM) reveals the morphological changes in the cement structure across the interface of the base-plate and the substrate, modification of the steel surface by the cement and the corrosion pattern beneath the barnacle-base. Fourier transform infrared spectroscopy (FTIR) of the corrosion products show that they are composed of mainly oxides of iron thereby implying that the corrosion is aerobic in nature. A model for the etching and corrosion mechanism is proposed based on our observations. PMID:20641172

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

2010-09-01

234

Barnacle cement: An etchant for stainless steel 316L?  

PubMed

Localized corrosion of stainless steel beneath the barnacle-base is an unsolved issue for the marine industry. In this work, we clearly bring out for the first time the role of the barnacle cement in acting as an etchant, preferentially etching the grain boundaries, and initiating the corrosion process in stainless steel 316L. The investigations include structural characterization of the cement and corroded region, and also chemical characterization of the corrosion products generated beneath the barnacle-base. Structural characterization studies using scanning electron microscopy (SEM) reveals the morphological changes in the cement structure across the interface of the base-plate and the substrate, modification of the steel surface by the cement and the corrosion pattern beneath the barnacle-base. Fourier transform infrared spectroscopy (FTIR) of the corrosion products show that they are composed of mainly oxides of iron thereby implying that the corrosion is aerobic in nature. A model for the etching and corrosion mechanism is proposed based on our observations. PMID:20638997

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

2010-05-12

235

Thermochemical processes for solar hydrogen production  

SciTech Connect

The use of solar energy to produce hydrogen from water is an attractive concept that merits a continuing research and development effort. The base technology being developed for solar thermal power can be applied effectively in the production of hydrogen from water. Hydrogen production could be based on advanced water electrolysis and economic solar hydrogen become an eventual reality even if advanced processes do not prove to be feasible. Thermochemical cycles for decomposing water promise higher efficiencies if cycles can be developed that match the characteristics of solar heat sources. At present, cycles based on sulfuric acid are the most fully developed processes and they can be adapted to solar thermal systems and serve as standards of comparison for new cycles as they are discovered and developed. Advanced cycles based on solids decomposition reactions should interface advantageously with solar thermal systems and several cycles based on such reactions are under experimental evaluation.

Bowman, M.G.

1982-01-01

236

Multiphase Flow Modeling of Biofuel Production Processes  

SciTech Connect

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

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

2011-06-01

237

Integration of Supplier and Customer's Production Processes  

Microsoft Academic Search

\\u000a This paper is based on the findings from the project funded by the Ministry of Science and Higher Education of Poland. It\\u000a presents the application of value stream mapping in supply chains and some inadequacy of this method for supply chain integration.\\u000a Based on the findings, a new Supplier Customer Production process Integration SCPI methodology is proposed. The paper presents

Marek Eisler; Remigiusz Horbal

2009-01-01

238

A review on FAME production processes  

Microsoft Academic Search

Among the options explored for alternative energy sources, bio-diesel is one of the most attractive. This paper discussed about the various production processes, few of which are applied at industrial level also, to produce basically FAME (later can be utilized as bio-diesel after purification) and will be termed as bio-diesel in this paper. Transesterification of vegetable oils\\/fats and extraction from

Amish P. Vyas; Jaswant L. Verma; N. Subrahmanyam

2010-01-01

239

Formation, release and control of dioxins in cement kilns.  

PubMed

Co-processing of hazardous wastes in cement kilns have for decades been thought to cause increased emissions of PCDD/PCDFs--a perception that has been evaluated in this study. Hundreds of PCDD/PCDF measurements conducted by the cement industry and others in the last few years, on emissions and solid materials, as well as recent test burns with hazardous wastes in developing countries do not support this perception. Newer data has been compared with older literature data and shows in particular that many emission factors have to be reconsidered. Early emission factors for cement kilns co-processing hazardous waste, which are still used in inventories, are shown to be too high compared with actual measurements. Less than 10 years ago it was believed that the cement industry was the main contributor of PCDD/PCDFs to air; data collected in this study indicates however that the industry contributes with less than 1% of total emissions to air. The Stockholm Convention on POPs presently ratified by 144 parties, classifies cement kilns co-processing hazardous waste as a source category having the potential for comparatively high formation and release of PCDD/PCDFs. This classification is based on early investigations from the 1980s and 1990s where kilns co-processing hazardous waste had higher emissions compared to those that did not burn hazardous waste. However, the testing of these kilns was often done under worst case scenario conditions known to favour PCDD/PCDF formation. More than 2000 PCDD/PCDF cement kiln measurements have been evaluated in this study, representing most production technologies and waste feeding scenarios. They generally indicate that most modern cement kilns co-processing waste today can meet an emission level of 0.1ngI-TEQ/m(3), when well managed and operated. In these cases, proper and responsible use of waste including organic hazardous waste to replace parts of the fossil fuel does not seem to increase formation of PCDD/PCDFs. Modern preheater/precalciner kilns generally seems to have lower emissions than older wet-process cement kilns. It seems that the main factors stimulating formation of PCDD/PCDFs is the availability of organics in the raw material and the temperature of the air pollution control device. Feeding of materials containing elevated concentrations of organics as part of raw-material-mix should therefore be avoided and the exhaust gases should be cooled down quickly in long wet and long dry cement kilns without preheating. PCDD/PCDFs could be detected in all types of solid samples analysed: raw meal, pellets and slurry; alternative raw materials as sand, chalk and different ashes; cement kiln dust, clinker and cement. The concentrations are however generally low, similar to soil and sediment. PMID:17698165

Karstensen, Kåre Helge

2007-08-14

240

Stability Analysis of a Cemented Rockfill Pillar.  

National Technical Information Service (NTIS)

The survival of many mines depends on their capability to maximize productivity while minimizing operating costs. The costs associated with cemented backfilling are best reduced by the optimization of mix design and thorough dimensioning. For environmenta...

H. Kuula

1996-01-01

241

Analysis of two lunar oxygen production processes  

NASA Astrophysics Data System (ADS)

Two processes for making oxygen on the moon - pyrolysis and hydrogen reduction of lunar ilmenite - are studied. HSC, a specialized process industry microcomputer program, is used to show all product species that are in equilibrium at specified temperatures and pressures for the two processes. Analysis of the hydrogen reduction of ilmenite showed that: increased temperature increases yields, increased pressure decreases yields, and contaminated feeds provide output contaminants. Analysis of the pyrolysis of regolith showed that low pressure is desirable in order to benefit the vaporization points of the various species. It is demonstrated that the different kinds of regolith vaporized in the pyrolysis provided maximum oxygen yields that varied from 27 to 33 percent by weight, and that the furnace temperature has to be maintained above 2500 C, with the best yields occurring above 2700 C.

Hernandez, Laura; Franklin, H. A.

242

Learning and improvement in product innovation processes: Enabling behaviors  

Microsoft Academic Search

Product Innovation is described as a continuous and cross-functional process involving all stages in the product life cycle. This approach gives way to study product innovation processes from a continuous improvement and learning viewpoint. The Continuous Improvement in the global product MAnagement (CIMA) model describes learning and improvement within product innovation processes in terms of a number of interrelated variables:

José F. B. Gieskes; Ilse Langenberg

2001-01-01

243

Process simulation and economical evaluation of enzymatic biodiesel production plant  

Microsoft Academic Search

Process simulation and economical evaluation of an enzymatic biodiesel production plant has been carried out. Enzymatic biodiesel production from high quality rapeseed oil and methanol has been investigated for solvent free and cosolvent production processes. Several scenarios have been investigated with different production scales (8 and 200mio. kg biodiesel\\/year) and enzyme price. The cosolvent production process is found to be

Lene Fjerbaek Sotoft; Ben-Guang Rong; Knud V. Christensen; Birgir Norddahl

2010-01-01

244

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

245

Selection of Production Processes for Utilization of Molasses.  

National Technical Information Service (NTIS)

Described is the prevailing position of the production and utilization of molasses in Pakistan and the different processes available for the utilization of molasses as animal feedstuffs, food products and chemical products. Each of these processes is desc...

F. H. Shah

1973-01-01

246

Analyses of Heavy Metals in Mineral Trioxide Aggregate and Portland Cement  

Microsoft Academic Search

IntroductionPortland cement is used in the construction industry as a binder in concrete. It is manufactured from chalk, limestone, and clay, which are clinkered at very high temperatures and ground with gypsum to form Portland cement. The raw materials and the manufacturing process can result in the inclusion of heavy metals in Portland cement. Portland cement with a four to

Matthew Schembri; George Peplow; Josette Camilleri

2010-01-01

247

Damper Drives in Cement Plants  

Microsoft Academic Search

The author comprehensively treats the design factors considered in matching control systems to process control devices employed in the Portland cement industry. New developments in the areas of fluidic, SCR, and hydraulic power units employed as final element actuators are discussed and areas of application suggested.

Edward J. Pokorney

1968-01-01

248

(Fission product transport processes in reactor accidents)  

SciTech Connect

The purpose of this trip was to participate in and to hold informal discussions with other participants in the International Centre for Heat and Mass Transfer (ICHMT) International Seminar on Fission Product Transport Processes held at Dubrovnik, Yugoslavia, during the week of May 22--26, 1989. There were 129 participants from 20 countries at the Seminar. The travelers delivered two invited lectures and presented four invited papers based upon NRC-sponsored work at Oak Ridge National Laboratory. One of the travelers also served as Chairman of the Session entitled Transport Phenomena in the Reactor Coolant System'' and appeared as a Panelist in the Closing Session of the Seminar.

Hodge, S.A.; Beahm, E.C.; Kress, T.S.; Malinauskas, A.P.

1989-06-14

249

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

Code of Federal Regulations, 2013 CFR

...2013-01-01 false Approval of labeling for egg products processed in exempted egg products processing plants. 590.680 Section...AND INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE EGG PRODUCTS INSPECTION INSPECTION OF EGGS AND...

2013-01-01

250

Health issues in plastics production and processing.  

PubMed

Plastic components are essential in countless applications. Plastics can be molded into virtually any shape or size and also formed into sheets, coatings, or laminates. Plastic materials may have equal strength, durability, and impact resistance as metals, yet they are often much lighter, a distinct advantage in the automobile industry. With different combinations of polymers and additives, the production of materials with unique properties and applications is seemingly limitless. Given the size and diversity of plastics-related employment, occupational health professionals are likely to be involved in assessing health issues related to plastic manufacturing and processing. As industrial and medical experience with these compounds has grown, so has the recognition of a variety of potential health hazards. Health professionals need to be familiar with the different sectors of this industry and the diverse materials and processes. PMID:10495485

Lewis, R

251

Development of a strontium-containing hydroxyapatite bone cement.  

PubMed

A new route was developed to synthesis a new type of strontium-containing hydroxyapatite (Sr-HAP) bone cement with precursors of tetracalcium phosphate (TTCP), strontium hydrogen phosphate (DSPA), dicalcium phosphate (DCPA), phosphate acid and water. The processing parameters and fundamental properties including pH value, setting time, compressive strength of final hardened body and the cytotoxicity for serial extracts of each cements were investigated. The result shows that the final product of the cement after setting for 24h is nonstoichiometic Sr-containing hydroxyapatite (Ca(10-m-x)Sr(x) square(m)(HPO4)y(PO4)6-y(OH)2-2m square2m, 0cement pastes approaches to 7.0-7.6 when they are mixed with a ratio of 1:1 of powder to liquid (P/L) in weight. The setting time of the cement pastes is 4-11 min for the initial one and 10-17 min for the final one when the concentration of diluted phosphate is in a range of 0.5-1.0 mol/l. The compressive strengths of the hardened cements with different molar ratios of Sr/(Sr+Ca) after subjected an immersion in simulated body fluid (SBF) increase uniformly from 1 day to 5 days, where they get maximum values, respectively, but then decrease till to 2 weeks. Especially for the CPC-1, with a Sr/(Sr+Ca) molar ratios of 5% in cement powder composition, the largest compressive strength gained at 5 days is 66.57 MPa and the lowest one gained at 2 weeks is 44.75 MPa, which matches the value of human bones and can be expected to use in clinic application in repairing the nonloading sites on account of the positive result of cytotoxicity test of the extracts of Sr-containing calcium phosphate cement (Sr-CPC). PMID:15664634

Guo, Dagang; Xu, Kewei; Zhao, Xiaoyun; Han, Yong

2005-07-01

252

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

253

Advanced Multi-Product Coal Utilization By-Product Processing Plant  

SciTech Connect

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

John Groppo; Thomas Robl; Robert Rathbone

2006-06-01

254

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

National Technical Information Service (NTIS)

The Benchmarking and Energy Savings Tool (BEST) Cement is a process-based tool based on commercially available efficiency technologies used anywhere in the world applicable to the cement industry. This version has been designed for use in China. No actual...

C. Galitsky L. Price N. Zhou W. Lan Z. Xuemin

2008-01-01

255

Multiple cemental tears.  

PubMed

A cemental tear is a pathologic condition in which a complete or incomplete separation of the cementum occurs along the root surface and is usually accompanied by a deep periodontal pocket. Past articles report that the incidence of cemental tears has usually been limited to 1 tooth per individual. We encountered a clinical case with cemental tears involving 14 teeth in 1 individual. Multiple cemental tears in 1 individual have not been previously described in the dental literature. We present the clinical and pathologic features of this rare case and suggest that the probable cause of multiple cemental tears is structural weakness of the cementum. PMID:22862978

Watanabe, Chie; Watanabe, Yoshihisa; Miyauchi, Mutsumi; Fujita, Minoru; Watanabe, Yoshiyuki

2012-03-05

256

CHH Cement Composite  

NASA Astrophysics Data System (ADS)

The compressive strength and electrical resistivity for hardened pastes produced from nanomodified Portland SR cement (CHH- Carbon Hedge Hog cement) were studied. The nanomodification included growing of carbon nanotubes (CNTs) and carbon nanofibers (CNFs) on the cement particles. Pastes having water to binder ratio of 0.5 were produced. The obtained hardened material was characterized by increased compressive strength in comparison with the reference specimens made from pristine SR cement, which was attributed to reinforcing action of the CNTs and CNFs. The electrical resistivity of CHH composite was lower by one order of magnitude in comparison with reference Portland cement paste.

Cwirzen, A.; Habermehl-Cwirzen, K.; Nasibulina, L. I.; Shandakov, S. D.; Nasibulin, A. G.; Kauppinen, E. I.; Mudimela, P. R.; Penttala, V.

257

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

258

[Cement removal with ultrasound in revision or total hip prosthesis].  

PubMed

Bone cement (polymethylmethacrylate, PMMA) removal during revision hip arthroplasty can be a tedious, time-consuming process. The usual methods of removing cement include high-speed drills, chisels, saws, and reamers, which are often associated with fracture or perforation of the femoral shaft. An alternative very promising method is cement removal with ultrasound. We present an ultrasonic device for rapid cement removal with minimum risk of trauma to the fragile femoral bone. The technique of cement removal with ultrasound is described and problems and risks are addressed. PMID:11417239

Schwaller, C A; Elke, R

2001-05-01

259

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

260

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

SciTech Connect

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, J [University of Maryland; Andres, Robert Joseph [ORNL; Marland, Gregg [ORNL

2008-01-01

261

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

262

Downstream Processing of Synechocystis for Biofuel Production  

NASA Astrophysics Data System (ADS)

Lipids and free fatty acids (FFA) from cyanobacterium Synechocystis can be used for biofuel (e.g. biodiesel or renewable diesel) production. In order to utilize and scale up this technique, downstream processes including culturing and harvest, cell disruption, and extraction were studied. Several solvents/solvent systems were screened for lipid extraction from Synechocystis. Chloroform + methanol-based Folch and Bligh & Dyer methods were proved to be "gold standard" for small-scale analysis due to their highest lipid recoveries that were confirmed by their penetration of the cell membranes, higher polarity, and stronger interaction with hydrogen bonds. Less toxic solvents, such as methanol and MTBE, or direct transesterification of biomass (without preextraction step) gave only slightly lower lipid-extraction yields and can be considered for large-scale application. Sustained exposure to high and low temperature extremes severely lowered the biomass and lipid productivity. Temperature stress also triggered changes of lipid quality such as the degree of unsaturation; thus, it affected the productivities and quality of Synechocystis-derived biofuel. Pulsed electric field (PEF) was evaluated for cell disruption prior to lipid extraction. A treatment intensity > 35 kWh/m3 caused significant damage to the plasma membrane, cell wall, and thylakoid membrane, and it even led to complete disruption of some cells into fragments. Treatment by PEF enhanced the potential for the low-toxicity solvent isopropanol to access lipid molecules during subsequent solvent extraction, leading to lower usage of isopropanol for the same extraction efficiency. Other cell-disruption methods also were tested. Distinct disruption effects to the cell envelope, plasma membrane, and thylakoid membranes were observed that were related to extraction efficiency. Microwave and ultrasound had significant enhancement of lipid extraction. Autoclaving, ultrasound, and French press caused significant release of lipid into the medium, which may increase solvent usage and make medium recycling difficult. Production of excreted FFA by mutant Synechocystis has the potential of reducing the complexity of downstream processing. Major problems, such as FFA precipitation and biodegradation by scavengers, account for FFA loss in operation. Even a low concentration of FFA scavengers could consume FFA at a high rate that outpaced FFA production rate. Potential strategies to overcome FFA loss include high pH, adsorptive resin, and sterilization techniques.

Sheng, Jie

263

Evaluation of Hazardous-Waste Incineration in a Cement Kiln at San Juan Cement.  

National Technical Information Service (NTIS)

Some attractive alternatives to hazardous waste incineration which make use of a waste's heat content are cofiring of hazardous wastes in high temperature industrial processes. Many such processes, which include cement and dolomite kilms, glass furnaces, ...

J. A. Peters T. W. Hughes R. E. Mournighan

1983-01-01

264

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

265

ULTRA-LIGHTWEIGHT CEMENT  

SciTech Connect

The objective of this project is to develop an improved ultra-lightweight cement using ultra-lightweight hollow glass spheres (ULHS). This report includes results from laboratory testing of ULHS systems along with other lightweight cement systems, including foamed and sodium silicate slurries. During this project quarter, comparison studies of the three cement systems examined several properties: tensile strength, Young's modulus, and shear bond. Testing to determine the effect of temperature cycling on the shear bond properties of the cement systems was also conducted. In addition, the stress-strain behavior of the cement types was studied. This report discusses a software program that is being developed to help design ULHS cements and foamed cements.

Fred Sabins

2002-04-29

266

ULTRA-LIGHTWEIGHT CEMENT  

SciTech Connect

The objective of this project is to develop an improved ultra-lightweight cement using ultra-lightweight hollow glass spheres (ULHS). 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

267

Ultrasonic process and ultraclean product of same  

US Patent & Trademark Office Database

An ultrasonic cleaning process having ultraclean characteristics and the product of this process are disclosed whereby a conventional ultrasonic cleaning bath is augmented via the use of a cleaning target support structure and an optional mechanical isolator whereby the cleaning target is permitted to be motional with respect to the source of ultrasonic excitation energy. This mechanical isolation permits ultrasonic harmonics that are normally damped (suppressed) in amplitude due to conventional mechanical connections between the bath and the containment vessel to be fully applied to the cleaning target, resulting in substantial reduction in overall cleaning time and an improvement in cleaning efficiency. Various embodiments of the proposed system and method are disclosed, with several being preferred. Namely, the use of a circular floating-ballast to support a glass or plastic beaker used as the containment vessel is preferred as well as the use of a circular floating-ballast to support a plastic bag used as the containment vessel. Either of these configurations isolates the cleaning target from the sides of the ultrasonic bath. This isolation reduces the effective mass of the structure comprising the cleaning target, the containment vessel, and the containment vessel support (ballast means) and permits ultrasonic harmonics to fully affect cleaning with minimal harmonic damping. Consistent cleaning time improvements of 20-80% over conventional prior art basket-type and containment vessel support cover methods has been observed, and the ultraclean product of the disclosed cleaning process has contamination characteristics that render the cleaning target of a different kind than that possible utilizing conventional ultrasonic cleaning techniques.

2001-12-11

268

Standardization of Components, Products and Processes with Data Mining  

Microsoft Academic Search

Data mining offers tools for extracting knowledge from databases. This paper discusses applications of data mining in standardization of components, products, and processes. Standardization of components is accomplished using association rules derived from customers' requirements. A design process is proposed for the standardization of products. The design of a unique standardized product, different standardized products, and a standardized product for

Bruno AGARD; Andrew KUSIAK

2004-01-01

269

Phosphate-bonded calcium aluminate cements  

DOEpatents

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

Sugama, Toshifumi (Mastic Beach, NY)

1993-01-01

270

40 CFR 161.162 - Description of production process.  

Code of Federal Regulations, 2013 CFR

...Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS DATA REQUIREMENTS FOR REGISTRATION OF ANTIMICROBIAL PESTICIDES Product Chemistry Data Requirements § 161.162 Description of production process. If the...

2013-07-01

271

Process-Product Research on Teaching: A Review of Criticisms.  

ERIC Educational Resources Information Center

Reviews the conceptualization, methodology, productivity, interpretation, and application of teaching research which focuses on the relation between classroom processes (teaching) and products (what students learn). (DE)

Gage, N. L.; Needels, Margaret C.

1989-01-01

272

Application of a system dynamics approach for assessment and mitigation of CO2 emissions from the cement industry.  

PubMed

A system dynamics model based on the dynamic interactions among a number of system components is developed to estimate CO(2) emissions from the cement industry in India. The CO(2) emissions are projected to reach 396.89 million tonnes by the year 2020 if the existing cement making technological options are followed. Policy options of population growth stabilisation, energy conservation and structural management in cement manufacturing processes are incorporated for developing the CO(2) mitigation scenarios. A 42% reduction in the CO(2) emissions can be achieved in the year 2020 based on an integrated mitigation scenario. Indirect CO(2) emissions from the transport of raw materials to the cement plants and finished product to market are also estimated. PMID:16307842

Anand, Shalini; Vrat, Prem; Dahiya, R P

2005-11-22

273

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

274

Process for the production of nickel alloys  

US Patent & Trademark Office Database

The process for production of a nickel alloy having a maximum sulphur content of 0.05% in a converter by treatment of a crude ferro-nickel melt having a sulphur content of about 0.10% to 0.50% with oxygen and lime to form a slag and removal of the slag is improved by introducing at least a part of the required amount of lime as lime powder, together with oxygen, by injection tuyeres under the surface of the melt using tuyeres consisting of concentric pipes wherein the oxygen is surrounded by hydrocarbons. This improvement reduces to a maximum of two, the slag changes required to reduce the sulfur content to 0.05% or lower.

1980-04-29

275

Reusing pretreated desulfurization slag to improve clinkerization and clinker grindability for energy conservation in cement manufacture.  

PubMed

The purpose of this study was to combine the physical pretreatments of grinding, sieving, and magnetic-separation processes to reclaim iron-rich materials from the desulfurization slag, and to use the remainder for cement clinker production. The iron-rich materials can be separated out efficiently by grinding for 30 min and sieving with a 0.3 mm mesh. The non-magnetic fraction of the particles smaller than 0.3 mm was in the majority, and proved to be suitable for use as a cement raw material. The raw mixes prepared with a pretreated desulfurization slag had a relatively high reactivity, and the temperature at which alite forms was significantly reduced during the clinkerization process. The clinkers produced with 10% desulfurization slag had a high level of alite and good grindability. Generally, the improvements in clinkerization and clinker grindability are beneficial to energy conservation in cement manufacture. PMID:20493627

Chen, Ying-Liang; Chang, Juu-En; Shih, Pai-Haung; Ko, Ming-Sheng; Chang, Yi-Kuo; Chiang, Li-Choung

2010-05-20

276

Anisotropic porous metals production by melt processing  

SciTech Connect

The collapse of the Soviet Union has left many of its scientific institutes and technical universities without their traditional backbone of financial support. In an effort to stem the export of science to nations advocating nuclear proliferation, and to acquire potentially useful technology, several US government-sponsored programs have arise to mine the best of former USSR scientific advances. In the field of metallurgy, the earliest institutes to be investigated by Sandia National Laboratories are located in Ukraine. In particular, scientists at the State Metallurgical Academy have developed unique porous metals, resembling what could be described as gas-solid ``eutectic``. While porous metals are available in the US and other western countries, none have the remarkable structure and properties of these materials. Sandia began a collaborative program with the Ukrainian scientists to bring this technology to the US, verify the claims regarding these materials, and begin production of the so-called Gasars. This paper will describe the casting process technology and metallurgy associated with the production of Gasars, and will review the progress of the collaborative project.

Shapovalov, V.; Boiko, L. [State Metallurgical Academy of Ukraine, Dnepropetrovsk (Ukraine); Baldwin, M.D.; Maguire, M.C.; Zanner, F.J. [Sandia National Labs., Albuquerque, NM (United States). Liquid Metal Processing Lab.

1997-02-01

277

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

278

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

279

Microwave radiometry for cement kiln temperature measurements.  

PubMed

The maximum temperature inside a cement kiln is a critical operating parameter, but is often difficult or impossible to measure. We present here the first data that show a correlation between cement kiln temperature measured using a microwave radiometer and product chemistry over an eight-hour period. The microwave radiometer senses radiation in the 12-13 GHz range and has been described previously [Stephan and Pearce (2002), JMPEE 37: 112-124]. PMID:17645204

Stephan, Karl D; Wang, Lingyun; Ryza, Eric

2007-01-01

280

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

281

48 CFR 870.111-5 - Frozen processed food products.  

Code of Federal Regulations, 2012 CFR

...Frozen processed food products that contain meat, poultry, or a significant proportion...frozen processed food products that contain meat, poultry or a significant proportion of...accordance with USDA regulations governing meat, poultry, or egg inspection. A...

2012-10-01

282

[Glass ionomer cementing in stomatological practice].  

PubMed

Glass ionomers cements represent a cement system which develops by a reaction between a polyalchenic acid, usually a homo- or a copolymer of acrylic acid and a ion donor, usually an aluminium fluorosilicate glass. Introduction of these ionomers in the stomatological practice was determined by their remarkable adherence to dentin, by pulpal and parodontal biocompatibility, and because of the fact that they deliver continuously fluorine over a long period of time. These cements provide a good marginal sealing of the obturation. In the last years a new generation of glass ionomers cements has been introduced, that "Cormat" cements, in which the glass powder is intimately linked to a pure silver metallic powder by a synthetization process, and this provides a greatly increased resistance to abrasion, as compared to conventional glass ionomer cements. Presently glass ionomer cements have become increasingly known in the stomatological practice and they are used preferentially for base obturations, under obturations with composites on lateral teeth, in the treatment of mylolysis and for coronary erosions determined by brushing, which do not need preparation of retention cavities. They are also used for coronary reconstruction, and the treatment of atopical microcavities of occluding decay processes on the lateral teeth that have induced limited enamel losses. The perspective of these cements in the stomatological practice depends however on an improved translucency, which, for the present at least, does not match that of silicates and composites, as well as on an improved resistance to bending, and even the "Cormat" cements are inferior to silver amalgam which is used in the obturation of classical class II cavities. PMID:2101262

Andreescu, C; Iliescu, A

283

40 CFR 158.330 - Description of production process.  

Code of Federal Regulations, 2011 CFR

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

2011-07-01

284

40 CFR 158.330 - Description of production process.  

Code of Federal Regulations, 2012 CFR

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

2012-07-01

285

40 CFR 161.162 - Description of production process.  

Code of Federal Regulations, 2012 CFR

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

2012-07-01

286

40 CFR 161.162 - Description of production process.  

Code of Federal Regulations, 2011 CFR

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

2011-07-01

287

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

USGS Publications Warehouse

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

Kelly, Thomas

1998-01-01

288

Association rule mining for product and process variety mapping  

Microsoft Academic Search

Today's manufacturers strive to design and produce a large number of customized products at low cost and quick turnround in order to survive market competition. The consequence of high product variety manifests itself through an exponentially increased number of process variants, which introduces significant constraints to production planning and control. Leveraging upon product and process families has been well recognized

J. Jiao; L. Zhang; Y. Zhang; S. Pokharel

2008-01-01

289

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

290

Detarium Microcarpum Polysaccharide as a Stabilizer in Processed Fruit Products  

Microsoft Academic Search

Detarium microcarpum (Dm) seed polysaccharide was evaluated as a stabilizer, thickening and gelling agent in processed fruit products such as mango beverage, orange beverage, orange squash, tomato sauce and pineapple jam. The functional properties of the Dm seed polysaccharide were studied with respect to pectin in these processed fruit products. The concentration of Dm polysaccharide in different processed fruit products

Jane C Onweluzo; M. R. Vijayalakshmi; P. Vijayanand; W. E. Eipeson

1999-01-01

291

Soft X-ray Microscopy of Green Cements  

Microsoft Academic Search

The present status of the cement and concrete industry is not sustainable. The production of Portland cement is responsible for 7% of the CO2 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

P. J. M. Monteiro; M. Mancio; A. P. Kirchheim; R. Chae; J. Ha; P. Fischer; T. Tyliszczak

2011-01-01

292

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

293

Soft X-ray Microscopy of Green Cements  

NASA Astrophysics Data System (ADS)

The present status of the cement and concrete industry is not sustainable. The production of Portland cement is responsible for 7% of the CO2 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.; Kirchheim, A. P.; Chae, R.; Ha, J.; Fischer, P.; Tyliszczak, T.

2011-09-01

294

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

NASA Astrophysics Data System (ADS)

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

Constantinides, Margarita

295

Integrated Product and Process Data for B2B Collaboration  

SciTech Connect

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

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

2003-09-01

296

Cement-related burns.  

PubMed

Burns caused by prolonged contact of wet cement with skin are common in this country. Recent literature has highlighted other ways in which the use and manufacture of cement can lead to burn injuries, notably through explosion and contact with hot powder during manufacturing. These injuries are uncommon in this country and potentially very serious. Case studies are presented of two men injured in such a way in the same incident at a cement-manufacturing plant. PMID:8982549

Morley, S E; Humzah, D; McGregor, J C; Gilbert, P M

1996-12-01

297

ULTRA-LIGHTWEIGHT CEMENT  

SciTech Connect

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

Fred Sabins

2003-01-31

298

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

Federal Register 2010, 2011, 2012, 2013

...No. 731-TA-461 (Third Review)] Gray Portland Cement and Cement Clinker From...revocation of the antidumping duty order on gray Portland cement and cement clinker from...Publication 4281 (December 2011), entitled Gray Portland Cement and Cement Clinker...

2011-12-08

299

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

300

Nanocrystalline tetracalcium phosphate cement.  

PubMed

Calcium hydroxide cements can lack long-term stability and achieve sustained release by matrix-controlled diffusion of hydroxyl ions. Tetracalcium phosphate (TTCP) hydrolyzes slowly to form calcium hydroxide and a thin insoluble apatite layer that prevents further reaction. In this study, mechanical amorphization was used to create a setting calcium-hydroxide-releasing cement from TTCP. The effect of high-energy ball milling of TTCP on the mechanical properties of the cement was investigated. X-ray diffraction data were used to determine the phase composition of the set cements. An accelerated in vitro test compared pH of water after prolonged boiling of nanocrystalline TTCP cements and a calcium salicylate material. As milling time increased, cement compressive strength and degree of conversion increased. Hydroxyl ion release from the cement was comparable with that from a calcium salicylate material. This new cement system offers the antimicrobial potential of calcium salicylate materials combined with the long-term stability of insoluble apatite cements. PMID:15111637

Gbureck, U; Barralet, J E; Hofmann, M P; Thulí, R

2004-05-01

301

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

PubMed

Ceramic tiles are widely used by the construction industry, and the manufacturing process of ceramic tiles generates as a major residue mud derived from the polishing step. This residue is too impure to be reused in the ceramic process and is usually discarded as waste in landfills. But the analysis of the particle size and concentration of silica of this residue shows a potential use in the manufacture of building materials based on portland cement. Tests were conducted on cement pastes and mortars using the addition of 10% and 20% (mass) of the residue. The results of compressive strength in mortars made up to 56 days showed a significant increase in compressive strength greater than 50%. The result of thermogravimetry shows that portlandite is consumed by the cement formed by the silica present in the residue in order to form calcium silicate hydrate and featuring a pozzolanic reaction. This effect improves the performance of cement, contributes to research and application of supplementary cementitious materials, and optimizes the use of portland cement, reducing the environmental impacts of carbon dioxide emissions from its production. PMID:22316267

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

2012-02-08

302

PRODUCTION OF CARBON PRODUCTS USING A COAL EXTRACTION PROCESS  

SciTech Connect

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

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

2005-12-12

303

Writing in dyslexia: product and process.  

PubMed

Research on dyslexia has largely centred on reading. The aim of this study was to assess the writing of 13 children with and 28 without dyslexia at age 11?years. A programme for keystroke logging was used to allow recording of typing activity as the children performed a sentence dictation task. Five sentences were read aloud twice each. The task was to type the sentence as correctly as possible, with no time constraints. The data were analysed from a product (spelling, grammar and semantics) and process (transcription fluency and revisions) perspective, using repeated measures ANOVA and t-tests to investigate group differences. Furthermore, the data were correlated with measures of rapid automatic naming and working memory. Results showed that the group with dyslexia revised their texts as much as the typical group, but they used more time, and the result was poorer. Moreover, rapid automatic naming correlated with transcription fluency, and working memory correlated with the number of semantic errors. This shows that dyslexia is generally not an issue of effort and that cognitive skills that are known to be important for reading also affect writing. PMID:23720272

Morken, Frøydis; Helland, Turid

2013-05-29

304

Separation of products from mild coal gasification processes  

Microsoft Academic Search

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

Wallman

1991-01-01

305

Product development using process monitoring and NDE data fusion  

Microsoft Academic Search

Composite process\\/product development relies on both process monitoring information and nondestructive evaluation measurements for determining application suitability. In the past these activities have been performed and analyzed independently. Our present approach is to present the process monitoring and NDE data together in a data fusion workstation. This methodology leads to final product acceptance based on a combined process monitoring and

Todd Peterson; Richard H. Bossi

1998-01-01

306

Assembly and Disassembly Processes in Product Life Cycle Perspectives  

Microsoft Academic Search

Industrial companies change the paradigms of business operations from optimisation of manufacturing processes to optimisation of products life cycles in order to activate the value of products, taking into account the potentials of product services in all phases of each product's life. From design to the end of their life capital intensive products, like manufacturing or assembly systems, are linked

E. Westkämper

2003-01-01

307

Effect of surface-active substances on the rate of production of copper powder from copper sulphate solutions by cementation on zinc rods in gas sparged reactors  

Microsoft Academic Search

The effect of surface-active substances on the rate of diffusion-controlled cementation of copper on a single vertical zinc rod from dilute copper sulphate solutions was studied. Variables investigated were: nitrogen superficial velocity, concentration and type of surface-active substance. These variables were studied for their effect on the mass transfer coefficient of copper cementation. The mass transfer coefficient was found to

Mahmoud A. Zarraa

1996-01-01

308

Low fluid leakoff cementing compositions and filtration control additive for cement  

SciTech Connect

A cementing composition is described, for cementing oil or gas wells penetrating subterranean formations, capable of forming a fluid slurry when mixed with water comprising: dry hydraulic cement; and a filtration control additive of from about 0.2 to 5.0 percent by weight, based upon dry hydraulic cement, of finely ground peanut hulls, wherein 10 percent or more of the finely ground peanut hulls is in the particle size range of less than 20 standard sieve mesh and greater than 500 standard sieve mesh. In a process for cementing a casing in an oil or gas well penetrating a subterranean formation wherein a cement slurry, formed by mixing water and hydraulic cement, is pumped down the well to flow upwardly between the casing and the subterranean formation, the improvement is described comprising: utilizing as a filtration control additive of from about 0.2 to 5.0 percent by weight, based upon dry hydraulic cement, of finely ground peanut hulls, and utilizing finely ground peanut hulls wherein 10 percent or more of the finely ground peanut hulls is in the particle size range of less than 20 standard sieve mesh and greater than 500 standard sieve mesh.

Forrest, G.T.

1993-07-20

309

Cement clinker: A environmental sink for residues from hazardous waste treatment in cement kilns  

SciTech Connect

About 70% of all of the liquid and solid hazardous wastes commercially incinerated in the United States is being burned in cement kilns. The process inevitably results in residues, primarily heavy metals, entering the clinker and waste dusts (cement kiln dust, CKD) produced by these kilns. The effects of this trend on the nature and chemical composition of cement, actual and future, are discussed. The wastes burned by cement kilns are expected to increasingly have higher levels of heavy metals per Btu. In general, the effects are very simple to describe but have as yet unknown consequences. The present American Society for Testing and Materials (ASTM) standard does not effectively control hazardous waste burning residues in Portland Cement. The regulatory and economic pressures on CKD disposal suggest that much of it, and its heavy metal residues, will, in time, end up in the clinker and the resultant cement. The end point to the trend is the ability to make cement that passes the performance specifications while containing high levels of heavy metals. The only other alternative is to maximize the levels of heavy metals in the CKD, minimize the amount of CKD, and dispose of it as a hazardous waste. It is recommended that an effort to correlate heavy metal levels in clinker with adverse effects by undertaken, a new standard for cement containing hazardous and other waste residuals be developed, and labeling be required.

Kleppinger, E.W. (EWK Consultants Inc., Washington, DC (United States))

1993-01-01

310

Optimal Production Decisions for Deteriorating Items with Investment on Production Processes  

Microsoft Academic Search

The imperfect production processes always leads to imperfect products and decreases the profit of business. Improving the production processes by increasing the investment cost will decrease the defective percentage of the items. In this study, we develop an EPQ model of deteriorating items with investment on imperfect production processes. An algorithm is developed to derive a replenishment policy such that

Ping-hui Hsu; Hui-ming Teng; Hui-ming Wee

2009-01-01

311

Formation of hydroxyapatite in new calcium phosphate cements  

Microsoft Academic Search

SynopsisTetracalcium phosphate (TTCP) has been shown previously to be an essential component of self-setting calcium phosphate cements that form hydroxyapatite (HA) as the only end-product. We report herein on a new self-setting calcium phosphate cement that does not contain TTCP. These cements consist of dicalcium phosphate anhydrous (DCPA), dicalcium phosphate dihydrate (DCPD), ?-tricalcium phosphate, or amorphous calcium phosphate and, as

S. Takagi; L. C. Chow; K. Ishikawa

1998-01-01

312

Hydration of calcium sulfoaluminate cements — Experimental findings and thermodynamic modelling  

Microsoft Academic Search

Calcium sulfoaluminate cements (CSA) are a promising low-CO2 alternative to ordinary Portland cements and are as well of interest concerning their use as binder for waste encapsulation. In this study, the hydration of two CSA cements has been investigated experimentally and by thermodynamic modelling between 1 h and 28 days at w\\/c ratios of 0.72 and 0.80, respectively.The main hydration product of

Frank Winnefeld; Barbara Lothenbach

2010-01-01

313

Formation of hydroxyapatite in new calcium phosphate cements.  

PubMed

Tetracalcium phosphate (TTCP) has been shown previously to be an essential component of self-setting calcium phosphate cements that form hydroxyapatite (HA) as the only end-product. We report herein on a new self-setting calcium phosphate cement that does not contain TTCP. These cements consist of dicalcium phosphate anhydrous (DCPA), dicalcium phosphate dihydrate (DCPD), alpha-tricalcium phosphate, or amorphous calcium phosphate and, as an additional source of calcium, calcium hydroxide or calcium carbonate. These cements require the use of a phosphate (0.2 moll(-1) or higher) solution or a high pH solution as the cement liquid. The cements harden in relatively short time (5-30 min) and form HA as the dominant end-product in 24 h. The diametral tensile strengths of the 24-h samples are in the range of 0.2 to 7.5 MPa. Results from X-ray diffraction studies suggest that the cement setting is caused by rapid HA formation induced by the high phosphate concentration of the cement liquid. Because DCPA and DCPD are highly soluble at pH values above 12.7, which is the pK3 of phosphoric acid, high phosphate concentration in the slurry solution was also attainable by using a highly alkaline solution as the cement liquid. The physicochemical properties of these cements are comparable to those of TTCP-containing cements, and the new cements may be expected to have in vivo characteristics similar to those of TTCP-containing cements as well. PMID:9830985

Takagi, S; Chow, L C; Ishikawa, K

1998-09-01

314

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

SciTech Connect

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

Hemmings, Raymond T.

2005-12-31

315

Radiation sterilization of a bifunctional cement formulation of hydroxilapatite-plaster-polymers.  

PubMed

A sterilization method based on the use of gamma ionizing radiation was applied to a cement formulation of hydroxilapatite, plaster and polymers to be used in bone restorations in dental, aesthetic, and neurological surgery. After the cement was exposed to a dose of 21.5 kGy it reached the sterility assurance level which was necessary for its employment in surgical applications as specified by International Standard ISO ordinate 11137: Radiation Sterilization of Health Care Products. No variation in the initial cement composition or processing parameters, such as working or setting time and molding quality was observed due to sterilization. Its characteristics as a drug delivery system were also not affected. Therefore, radiation sterilization provides a feasible alternative to conventional sterilization methods such as dry/wet heat and ethylene oxide. PMID:10415558

Sainz Vidal, D; Rodriquez Napoles, D; Fuentes Estevez, G; Guerra, M; Arcis Soriano, W; Peon Aves, E; Diaz Argota, J M; Zaldivar Silva, D

1999-06-18

316

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

SciTech Connect

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

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

1997-03-01

317

Effect of mineral trioxide aggregate cements on transforming growth factor beta1 and bone morphogenetic protein production by human fibroblasts in vitro.  

PubMed

The aim of this study was to evaluate and compare the effects of two commercial mineral trioxide aggregate (MTA) cements (ProRoot MTA and MTA Angelus) on transforming growth factor (TGF)-beta1 and bone morphogenetic protein (BMP)-2 levels produced by cultured human gingival fibroblasts (HGFs). Human gingival tissues were obtained from individuals with healthy periodontium. HGFs were grown at 37 degrees C in humidified atmosphere of 5% CO(2) in Dulbecco's modified Eagle's medium, supplemented with 10% fetal calf serum, penicillin, and streptomycin. After 24 and 72 hours of exposure to the MTA products, HGF viability was determined by using 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl tetrazolium bromide assay. TGF-beta1 and BMP-2 levels in cell-free culture media were determined by enzyme-linked immunosorbent assay. Cell viability of the test groups was significantly lower than that of control at 24 and 72 hours (p < 0.05) but showed an increase at 72 hours (p < 0.05). Both test groups showed increased TGF beta-1 levels at 72 hours (p < 0.05), whereas the MTA Angelus group displayed higher TGF beta-1 levels than control and ProRoot MTA groups at 24 and 72 hours (p < 0.05). At 24 hours, BMP-2 levels of the ProRoot group were significantly higher than that of MTA Angelus (p < 0.05). Both test materials increased the BMP-2 levels within time (p < 0.05) and displayed similar levels at 72 hours (p > 0.05). These results suggest that both MTA products are capable of stimulating HGF to produce BMP-2, whereas the stimulatory effect for TGF beta-1 is material dependent. PMID:17368336

Guven, Gunseli; Cehreli, Zafer C; Ural, Ali; Serdar, Muhittin A; Basak, Feridun

2007-04-01

318

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

2004-01-30

319

Pozzolan Cement Study.  

National Technical Information Service (NTIS)

This research study was to evaluate the performance of a Type 1P cement concrete pavement constructed on an experimental project as compared to a regular Type 1(B) cement concrete pavement. The sections were evaluated for strength, durability, skid resist...

S. M. Law M. Rasoulian

1979-01-01

320

Ultra-Lightweight Cement.  

National Technical Information Service (NTIS)

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. D...

F. Sabins

2003-01-01

321

Process simulation and economical evaluation of enzymatic biodiesel production plant.  

PubMed

Process simulation and economical evaluation of an enzymatic biodiesel production plant has been carried out. Enzymatic biodiesel production from high quality rapeseed oil and methanol has been investigated for solvent free and cosolvent production processes. Several scenarios have been investigated with different production scales (8 and 200 mio. kg biodiesel/year) and enzyme price. The cosolvent production process is found to be most expensive and is not a viable choice, while the solvent free process is viable for the larger scale production of 200 mio. kg biodiesel/year with the current enzyme price. With the suggested enzyme price of the future, both the small and large scale solvent free production proved viable. The product price was estimated to be 0.73-1.49 euro/kg biodiesel with the current enzyme price and 0.05-0.75 euro/kg with the enzyme price of the future for solvent free process. PMID:20171880

Sotoft, Lene Fjerbaek; Rong, Ben-Guang; Christensen, Knud V; Norddahl, Birgir

2010-02-19

322

From Sentence Production to Text Production: Investigating Fundamental Processes.  

ERIC Educational Resources Information Center

Presents a review of cognitive psychology research dealing with the organization and functioning of oral and written language production mechanisms. Discusses works dealing with the microstructural aspects of language, primarily oral production. Describes how the research perspective has evolved from modular to connectionist models. Examines the…

Fayol, Michel

1991-01-01

323

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

324

Development of a Powder and/or Gas Cementation Process for Coating Molybdenum Alloys for High Temperature Protection.  

National Technical Information Service (NTIS)

As prepared W-2 coating on Mo-0.5Ti was found to be essentially MoSi2. Upon exposure at 2700F. the coating becomes three phase and develops an oxidation resistant glaze. A statistically designed experiment was run on two levels of each of nine process var...

H. Blumenthal N. Rothman

1964-01-01

325

Analysis of rheological properties of bone cements.  

PubMed

The rheological properties of three commercially available bone cements, CMW 1, Palacos R and Cemex ISOPLASTIC, were investigated. Testing was undertaken at both 25 and 37 degrees C using an oscillating parallel plate rheometer. Results showed that the three high viscosity cements exhibited distinct differences in curing rate, with CMW 1 curing in 8.7 min, Palacos R and Cemex ISOPLASTIC in 13 min at 25 degrees C. Furthermore it was found that these curing rates were strongly temperature dependent, with curing rates being halved at 37 degrees C. By monitoring the change of viscosity with time over the entire curing process, the results showed that these cements had differing viscosity profiles and hence exhibit very different handling characteristics. However, all the cements reached the same maximum viscosity of 75 x 10(3) Pa s. Also, the change in elastic/viscous moduli and tan delta with time, show the cements changing from a viscous material to an elastic solid with a clear peak in the viscous modulus during the latter stages of curing. These results give valuable information about the changes in rheological properties for each commercial bone cement, especially during the final curing process. PMID:17277981

Nicholas, M K D; Waters, M G J; Holford, K M; Adusei, G

2007-02-03

326

Trends in Processing Technologies for Dried Aquatic Products  

Microsoft Academic Search

Fresh aquatic products are rich in nutritional compounds and are an important source of good protein for humans. Dehydration processing technologies of aquatic products used in practice are a mix of old and new technologies. With the rapid development of drying technologies and steadily increasing living standards, drying processing techniques as well as types of products produced have changed fundamentally.

Yingqiang Wang; Min Zhang; Arun S. Mujumdar

2011-01-01

327

The process model to aid innovation of products conceptual design  

Microsoft Academic Search

Currently, designers often pay little attention to integrated innovation during the design process of products. In addition, the product assistance design systems mainly focus on the detailed design phrase and the construction function of mathematics models are often been neglected. In order to solve these problems, this paper proposes a conceptual design process model to aid multi-stage innovation of product

Wenqiang Li; Yan Li; Jian Wang; Xiaoying Liu

2010-01-01

328

Verification of product quality from process control.  

National Technical Information Service (NTIS)

Process models were developed to characterize the waste vitrification at West Valley, in terms of process operating constraints and glass compositions achievable. The need for verification of compliance with the proposed Waste Acceptance Preliminary Speci...

A. Drobot L. R. Bunnell W. P. Freeborn P. B. Macedo G. B. Mellinger

1989-01-01

329

Matrix control cementing slurry  

SciTech Connect

This patent describes a method of cementing a well bore. The method consists of 1.) mixing together at ambient temperatures at the well surface a hydraulic cement, water, in an effective amount to produce a pumpable slurry, and a polyvinyl acetate-polyvinyl alcohol polymer, which is insoluble in the slurry at ambient temperatures. The polymer has a greater than about 95 percent acetate groups converted to hydroxyl groups. The polymer is heated to actuable solubilization in the cement slurry at temperatures above about 120/sup 0/F. The solubilizing of the polyvinyl acetate-polyvinyl alcohol polymer in the slurry prior to the setting of the slurry by pumping the cement slurry to a desired location in the well bore. This action increases the temperature of the slurry; and 2.) allows the cement slurry to harden to a solid mass.

Arpenter, R.B.

1986-02-11

330

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

331

Swelling, shrinkage and creep: a mechanical approach to cement hydration  

Microsoft Academic Search

Recent advances in physical understanding of creep and shrinkage of cement paste suggest a novel approach to setting and hardening\\u000a processes. In high-strength concrete, due to a low water-cement ratio, self-desiccation occurs immediately after setting,\\u000a and capillary pressure produces compaction of the assembly of hydrating cement grains. For higher watercement ratio, water\\u000a possibly can withstand cavitation, but then the volumetric

P. Acker

2004-01-01

332

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

333

Distributed constraint processing for production logistics  

Microsoft Academic Search

The Fakos production planning system developed for Mercedes-Benz relies on a combination of multiagent and constraint technologies that intuitively represents production flow knowledge at automobile manufacturing plants. The prototype presented compares favorably with centralized constraint and operations research approaches

H. Baumgurtel

2000-01-01

334

Architectures, Representations and Processes of Language Production  

ERIC Educational Resources Information Center

The authors present an overview of recent research conducted in the field of language production based on papers presented at the first edition of the International Workshop on Language Production (Marseille, France, September 2004). This article comprises two main parts. In the first part, consisting of three sections, the authors review the…

Alario, F.-Xavier; Costa, Albert; Ferreira, Victor S.; Pickering, Martin J.

2006-01-01

335

Architectures, Representations and Processes of Language Production  

ERIC Educational Resources Information Center

|The authors present an overview of recent research conducted in the field of language production based on papers presented at the first edition of the International Workshop on Language Production (Marseille, France, September 2004). This article comprises two main parts. In the first part, consisting of three sections, the authors review the…

Alario, F.-Xavier; Costa, Albert; Ferreira, Victor S.; Pickering, Martin J.

2006-01-01

336

Coordination of Production and Transportation Scheduling in Steel Making Process  

Microsoft Academic Search

Steel making process is the key process where the product quality of the finished steel is mainly determined. The process consists of LD converter, secondary refining and continuous caster. From the refining of steel by LD converter to the solidification by continuous caster, a large amount of molten steel with high temperature is processed. In the process, a lot of

Yousuke Ozoe; Masami Konishi

2009-01-01

337

Experimental micromechanics of the cement-bone interface.  

PubMed

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 bone with microcracking (damage) to both. More overall damage occurred to 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 supported by 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

2008-06-01

338

Study of the properties of slag-alkali cements based on nickel slags  

SciTech Connect

The authors report results of a study of the use of one slag from the production of nonferrous metals to obtain slag-alkali cements. The study was conducted on slag from a nickel plant. As the liquid component they used solutions of sodium metasilicate, an alkali-soda melt, and sodium silicate of different densities. Since the given slag has a considerable content of SiO/sub 2/ and Al/sub 2/O/sub 3/, its structure contains siloxane (-O-Si-O-Si-O-) and alumooxane (-O-Al-O-) bonds. Thus, the hydration of such glass is determined by the rupture of these bonds as a result of the polarizing action of OH/sup -/ ions, and the characteristics of the cement stone are determined by the type and concentration of the alkali component. The study showed that it is possible to obtain high-strength cements based on nickel slags in combination with different alkaline components. Meanwhile, the activity of the cements can be increased by introducing certain additions such as Portland cement clinker and granulated blast-furnace slag. The use of soluble silicate salts as the liquid component is more promising, these salts producing an alkaline medium in solution. Hydrothermal processing is the best hardening regime.

Pankratov, V.L.; Kaushanskii, V.E.; Shelud'ko, V.P.

1986-09-20

339

Application of Product Model for Engineering Process Definition  

Microsoft Academic Search

Integration of all engineering related information in a single complex product model is one of the main purposes in computer system based engineering activities. Because engineering process highly depends on product development and application projects, its definition was first realized in product modeling environments at the application of product data management (PDM) systems. However, this administrative solution could not be

Aniko Szak´l

2011-01-01

340

A new kind of eco-cement made of cement kiln dust and granular blast furnace slag  

Microsoft Academic Search

A research project was conducted to manufacture eco-cement for sustainable development using cement kiln dust (CKD) and granular\\u000a blast furnace slag(GBFS). In the project, the burning process and mineral compositions of CKD clinker were investigated. Different\\u000a mineralizers such as CaSO4 and CaF2 sulfur and alkali content were considered. The strength of CKD and GBFS eco-cement were evaluated. The results indicate

Shen Weiguo; Zhou Mingkai; Zhao Qinglin

2006-01-01

341

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

SciTech Connect

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

O`Neal, G.W.

1996-04-01

342

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

343

21 CFR 820.70 - Production and process controls.  

Code of Federal Regulations, 2010 CFR

...CONTINUED) MEDICAL DEVICES QUALITY SYSTEM REGULATION Production and Process Controls ...adversely affect the device's quality. The removal or reduction...systems are used as part of production or the quality system, the...

2013-04-01

344

9 CFR 318.306 - Processing and production records.  

Code of Federal Regulations, 2010 CFR

...and the final internal product temperature. (2) Continuous-type systems...process schedule such as the initial temperature, cooker speed, and final internal product temperature. (Approved by the Office of Management and Budget...

2010-01-01

345

9 CFR 381.306 - Processing and production records.  

Code of Federal Regulations, 2010 CFR

...and the final internal product temperature. (2) Continuous-type systems...process schedule such as the initial temperature, cooker speed, and final internal product temperature. (Approved by the Office of Management and Budget...

2009-01-01

346

9 CFR 318.306 - Processing and production records.  

Code of Federal Regulations, 2010 CFR

...and the final internal product temperature. (2) Continuous-type systems...process schedule such as the initial temperature, cooker speed, and final internal product temperature. (Approved by the Office of Management and Budget...

2009-01-01

347

9 CFR 381.306 - Processing and production records.  

Code of Federal Regulations, 2010 CFR

...and the final internal product temperature. (2) Continuous-type systems...process schedule such as the initial temperature, cooker speed, and final internal product temperature. (Approved by the Office of Management and Budget...

2010-01-01

348

Multi-Product Cycling with Packaging in the Process Industry.  

National Technical Information Service (NTIS)

A practical problem often encountered in the polymerization processing industry involves the multi-product cycling problem in combination with the storage assignment problem. The research assumes that products are stocked as bulk good in a container park ...

R. Heuts P. Nederstigt W. Roebroek W. Selen

1992-01-01

349

Manufacturing Processes for Various Shaped Consumable Ordnance Products.  

National Technical Information Service (NTIS)

The work covered by this report consisted of the manufacture of a variety of different shaped combustible ordnance products. Matched metal molding and spiral wrapping processes were utilized with five different product formulations. Some difficulty was en...

P. L. DeLuca S. Westley

1982-01-01

350

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

351

Proactive product quality control: An integrated product and process control approach to MIMO systems  

Microsoft Academic Search

Real-time control of product performance parameters is a key for proactive quality control (QC), as it can prevent the occurrence of potential quality problems in the earliest stage of manufacturing. It is recognized that dynamic product QC must be coordinated with the control of the process through which the product is manufactured. The integrated product and process control (IPPC) design

Zheng Liu; Jie Xiao; Yinlun Huang

2009-01-01

352

Stabilization and solidification of Pb in cement matrices  

Microsoft Academic Search

Pb was incorporated to a series of cement matrices, which were submitted to different testes of solidified\\/stabilized product. The leaching behaviors of aqueous solution were monitored by graphite furnace atomic absorption spectroscopy (GF-AAS). The mechanical strengths were evaluated by unconfined compressive strength (UCS) at 7 and 28 ages. Data are discussed in terms of metal mobility along the cement block

Maria A. C. Gollmann; Márcia M. da Silva; Ângela B. Masuero; João Henrique Z. dos Santos

2010-01-01

353

A review of Australian research into natural fibre cement composites  

Microsoft Academic Search

Over the last three decades considerable research has been committed to finding an alternative fibre to replace asbestos in fibre cement products. Australian research was centred on natural fibres and ultimately it was a natural fibre, wood pulp fibre, that was responsible for the greatest replacement of asbestos in the beleaguered global fibre cement industry.This review reports some of the

Robert S. P. Coutts

2005-01-01

354

A Cost Analysis: Processing Maple Syrup Products.  

National Technical Information Service (NTIS)

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

N. K. Huyler L. D. Garrett

1979-01-01

355

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.

356

Process development for EUV mask production  

NASA Astrophysics Data System (ADS)

Absorber layer patterning process for low reflectivity tantalum boron nitride (LR-TaBN) absorber layer and chromium nitride (CrN) buffer layer were improved to satisfy high resolution pattern and high level critical dimension (CD) control. To make 100nm and smaller pattern size, under 300nm resist thickness was needed because of resist pattern collapse issue. We developed absorber layer dry etching process for 300nm thickness resist. Absorber layer patterning was done by a consequence of carbon fluoride gas process and chlorine gas process. We evaluated both gas processes and made clear each dry etching character. Sufficient resist selectivity, vertical side wall, good CD control and low buffer layer damage were obtained. Then, we evaluated how buffer layer dry etching affects EUV reflectivity. Finally, we evaluated EUV mask pattern defect inspection and defect repair. Sufficient contrast of mask pattern image and good repair result were obtained using DUV inspection tool and AFM nano-machining tool, respectively.

Abe, Tsukasa; Fujii, Akiko; Sasaki, Shiho; Mohri, Hiroshi; Hayashi, Naoya; Shoki, Tsutomu; Yamada, Takeyuki; Nozawa, Osamu; Ohkubo, Ryo; Ushida, Masao

2006-10-01

357

Machine vision for process industries: Monitoring, control, and optimization of visual quality of processes and products  

Microsoft Academic Search

A new paradigm for machine vision for the process industries is proposed, and a framework is illustrated through several industrial applications. The framework is designed for handling the stochastic nature of the visual quality of processes and products in the process industries. In this thesis visual quality means spectral (i.e., color) and\\/or textural appearance of processes and products where the

June Liu

2005-01-01

358

21 CFR 113.100 - Processing and production records.  

Code of Federal Regulations, 2010 CFR

... (4) Aseptic processing and packaging systems...both; retention time of containers...sterilization, sterilization cycle times and temperatures...container. (6) Food preservation methods...conjunction with thermal processing. Product...

2009-04-01

359

21 CFR 113.100 - Processing and production records.  

Code of Federal Regulations, 2010 CFR

... (4) Aseptic processing and packaging systems...both; retention time of containers...sterilization, sterilization cycle times and temperatures...container. (6) Food preservation methods...conjunction with thermal processing. Product...

2010-04-01

360

Computerized Production Process Planning. Volume 2. Benefit Analysis.  

National Technical Information Service (NTIS)

This report contains the results of a cost benefit analysis of various levels of computerized production process planning for cylindrical and non-cylindrical machined parts. The results of the study indicate that: Computer aided process planning can signi...

H. H. H. Shu J. C. Church J. P. Kornfeld

1976-01-01

361

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...

362

Maintaining Soil Processes for Plant Productivity and Community Dynamics.  

National Technical Information Service (NTIS)

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. Soil processes mediated by soil biota include decomposition, ...

W. G. Whitford J. E. Herrick

1995-01-01

363

The effect of white or grey PVC pipe and its joint solvents (primer and cement) on odour problems in drinking water distribution systems.  

PubMed

A study of the production of odour-causing compounds was conducted from the leaching of polyvinylchloride (PVC) pipe and its joints, primer and cement, into drinking water distribution systems. Flavour Profile Analysis (FPA), closed-loop stripping analysis--gas chromatography/mass spectrometry (CLSA-GC/MS) and sensory-GC analysis of white or grey PVC alone found no odour-causing compounds produced during the leaching experiments. FPA analysis of the PVC's primer and cement leached alone and/or when applied to grey or white PVC pipes produced a glue/varnish odour. A sweet/phenolic odour replaced the glue/varnish odour after the leached media were diluted with Milli-Q water to threshold odour intensity. Three compounds were responsible for the sweet/phenolic odour and were observed by sensoryGC analysis. The leaching study of the PVC pipe with its joint solvents (primer and cement) concluded that the original solvent compounds, and their reaction products that formed during the bonding process on the PVC pipe, were a primary source of the glue/varnish odour. The original compounds of the PVC primer and cement were not detected by CLSA-GC/MS, due to their high volatility during the CLSA extraction method and/or these compounds appeared in a solvent peak of the GC/MS analysis. However, the original primer and cement chemicals (acetone, tetrahydrofuran, methyl ethyl ketone, and cyclohexanone) had a glue/varnish odour. A total of nine odorous GC peaks were produced as reaction products from leaching of primer in water and white or grey PVC pipe with primer and cement, and white or grey PVC with primer only. None of these compounds were among the chemical ingredients in the original primer or cement. Four GC peaks with a sweet/phenolic odour were present due to the reaction products of the cement leached with white or grey PVC. None of these compounds were positively identified. PMID:17489407

Wiesenthal, K E; Suffet, I H

2007-01-01

364

Some factors affecting an increase in magnetic susceptibility of cement dusts  

Microsoft Academic Search

The aim of the research was to explain reasons of fluctuation in magnetic susceptibility of cement dusts and the consequences for the environment. The research comprised measurements of magnetic susceptibility and Fe content in dusts, and also in raw materials, additives, fuels, mixtures and clinkers used for cement production. The samples were taken in four cement plants located in Opole

Beata J Go?uchowska

2001-01-01

365

30 CFR 250.422 - When may I resume drilling after cementing?  

Code of Federal Regulations, 2013 CFR

... 2013-07-01 false When may I resume drilling after cementing? 250.422...Requirements § 250.422 When may I resume drilling after cementing? (a) After...production casing (or liners), you may resume drilling after the cement has been...

2013-07-01

366

30 CFR 250.422 - When may I resume drilling after cementing?  

Code of Federal Regulations, 2010 CFR

... 2010-07-01 false When may I resume drilling after cementing? 250.422...Requirements § 250.422 When may I resume drilling after cementing? (a) After...production casing (or liners), you may resume drilling after the cement has been...

2010-07-01

367

30 CFR 250.422 - When may I resume drilling after cementing?  

Code of Federal Regulations, 2010 CFR

... 2009-07-01 false When may I resume drilling after cementing? 250.422...Requirements § 250.422 When may I resume drilling after cementing? (a) After...production casing (or liners), you may resume drilling after the cement has been...

2009-07-01

368

Physical performances of blended cements containing calcium aluminosilicate glass powder and limestone  

Microsoft Academic Search

This work explores the suitability of calcium aluminosilicate (CAS) glass particles as an alternative to conventional supplementary cementitious materials (SCMs) such as fly ash and blast furnace slag. The reason for adding CAS glass particles to the cement blend is to reduce the CO2 emission of cement production at the same level of performance. For this purpose, blended cement mortars

Mette Moesgaard; Duncan Herfort; Mette Steenberg; Lise Frank Kirkegaard; Yuanzheng Yue

2011-01-01

369

Bone cement implantation syndrome.  

PubMed

Bone cement implantation syndrome (BCIS) is characterized by hypoxia, hypotension, cardiac arrhythmias, increased pulmonary vascular resistance and cardiac arrest. It is a known cause of morbidity and mortality in patients undergoing cemented orthopaedic surgeries. The rarity of the condition as well as absence of a proper definition has contributed to under-reporting of cases. We report a 59-year-old woman who sustained fracture of the neck of her left femur and underwent an elective hybrid total hip replacement surgery. She collapsed during surgery and was revived only to succumb to death twelve hours later. Post mortem findings showed multiorgan disseminated microembolization of bone marrow and amorphous cement material. PMID:23817399

Razuin, R; Effat, O; Shahidan, M N; Shama, D V; Miswan, M F M

2013-06-01

370

Integrated coke, asphalt and jet fuel production process and apparatus  

DOEpatents

A process and apparatus for the production of coke, asphalt and jet fuel from 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 some 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 these products from materials such as coal, oil shale and tar sands. 1 fig.

Shang, Jer Yu.

1989-10-17

371

Reduction of nitric oxide emissions on a full-scale cement kiln using primary air vitiation  

SciTech Connect

Combustion modifications previously investigated in a laboratory-scale furnace and a subscale cement kiln were evaluated for emission reduction potential and effect on cement product quality. The full-scale kiln was a long dry process kiln firing pulverized coal. The kiln is rated at 1080 tons of cement per day with a thermal input of 240 x 10/sup 6/ Btu/hr. Of the combustion modifications evaluated in the previous studies, vitiation of the primary air with inert gas (nitrogen) was considered to be the best alternative for NO reduction on the full-scale kiln. Baseline NO emissions were observed to vary considerably as the result of process variations. NO emission factor, expressed as lb NO/sub 2//ton of clinker varied from 5.5 to 13.5. The mean 24-hour emission factor was 8+. 0.8 lb NO/sub 2//ton of clinker. Low excess air tests reduced NO emissions by approximately 20 percent when kiln exit O/sub 2/ was decreased from 1.8 to 0.8 percent. During nitrogen injection tests primary air O/sub 2/ was decreased to 12.5-13.0 percent, and NO was reduced 25-30 percent. Analyses of the cement clinker indicate that product quality was not affected as result of the tests, however longer term tests are required before this method could be implemented on a regular bases.

Hunter, S.C.; Benson, R.C.

1985-01-01

372

Wet deposition of mercury within the vicinity of a cement plant before and during cement plant maintenance  

Microsoft Academic Search

Hg species (total mercury, methylmercury, reactive mercury) in precipitation were investigated in the vicinity of the Lehigh Hanson Permanente Cement Plant in the San Francisco Bay Area, CA., USA. Precipitation was collected weekly between November 29, 2007 and March 20, 2008, which included the period in February and March 2008 when cement production was minimized during annual plant maintenance. When

Sarah E. Rothenberg; Lester McKee; Alicia Gilbreath; Donald Yee; Mike Connor; Xuewu Fu

2010-01-01

373

Process for the production of diaminomaleonitrile  

US Patent & Trademark Office Database

A process for tetramerizing hydrogen cyanide to diaminomaleonitrile, wherein hydrogen cyanide is polymerized in an organic solvent in the presence of a basic catalyst and a cocatalyst of the group consisting of organic mercaptans and organic disulfides.

Kobayashi; Tatsumi (Kurashiki, JA); Nishiwaki; Eiji (Arai, JA); Yamazoe; Shigeharu (Tokyo, JA); Hoshino; Mitsuyuki (Urawa, JA); Yoshino; Sadafumi (Kurashiki, JA); Mikuma; Katsunori (Kurashiki, JA)

1976-07-27

374

Acidic solubility of luting cements  

Microsoft Academic Search

Objectives. Chemical disintegration of luting cements can adversely affect their long term success. The aim of the present study was to assess the susceptibility of zinc phosphate cement, glass ionomer cement and resin cement to erosion at various pH values.Methods. Zinc phosphate and glass ionomer cement samples were eroded in 0.3% citric acid adjusted to pH 3.0, 4.0, 5.0, 6.0

M Eisenburger; M Addy; A Roßbach

2003-01-01

375

A Scheduling Process Applied to Newspaper Production  

Microsoft Academic Search

This paper proposes a support system which helps in deciding the allocation of resources for newspaper production. The system is structured starting from a covering model with the objective of determining the best sequencing of n tasks in m machines, obeying the schedule of delivery of the tasks. In the application of this model, the problem of sequencing of the

A. K. A. de Castro; Placido Rogerio Pinheiro; G. G. Conrado de Souza

2006-01-01

376

Solar production of industrial process steam in chemical process industries  

SciTech Connect

The solar system consists of 950 square meters of Del single-axis, tracking, parabolic-trough, concentrating collectors. It was designed to produce a portion of the 420/degree/-530/degree/K steam utilized in a drying operation to reduce the moisture content of hectorite ore from 10 percent to 4 percent. (Hectorite is a hydrous magnesium silicate which, when refined, is of significant commercial interest because of its applications in various chemical and food processes). It is estimated that implementation of this solar system could result in an annual savings of 3.545 billion KJ (3.360 billion Btus), of the equivalent of 90 cubic meters (600 barrels) of oil and a net reduction of 1,860 kilograms (4100 pounds) of air pollutants annually. The technical, economic and institutional issues encountered in the course of this project are also discussed. The impact of the commercialization of solar energy applications in chemical processing industries is evaluated. 5 refs.

Sundaram, S.; Eldridge, B.G.

1981-01-01

377

Comparison of tuff and fly ash in blended cement  

SciTech Connect

The effect of tuff and two types of fly ash on the hydration of cement was studied. Compressive strength of cement mortars, pozzolanic activity index of tuff and fly ashes, rate of heat evolution of cement, nonevaporable water and calcium hydroxide content in the hardened cement pastes were determined. It was found that the mechanical strength of mortars containing fly ash, especially high-lime fly ash, was higher than that of mortars containing tuff. The pozzolanic activity index of fly ash, especially high-lime fly ash, was greater than that of tuff. The rate of heat evolution at the second exothermic peak was diminished with the addition of tuff or fly ash to the cement, but the second peak position and the length of induction period was almost the same for cements with and without tuff. Nevertheless, the addition of fly ash to cement had a retarding action on the time to reach the maximum thermal output at the second peak. The rate of development of hydration products, as monitored by nonevaporable water measurement, was higher for pastes with tuff than for pastes with fly ash during the early period of hydration, and this difference tends to disappear with time. The content of calcium hydroxide in the cement pastes was diminished due to the addition of tuff or fly ashes to cement, especially when tuff or the high-lime fly ash was used.

He, J-Y; Roy, D.M.; Scheetz, B.E.

1985-05-01

378

Mechanization and automation of production processes in turbine building  

Microsoft Academic Search

Specialists at the All-Union Institute of Planning and Technology of Energy Machine Building are working on the problem of mechanization and automation of production processes. One of the major technological processes being worked on is the production of welded units. At the present time the Institute has designed a centralized cutting and manufacturing shop in use at several metallurgical plants,

V. P. Slobodyanyuk

1984-01-01

379

Medicare medical nutrition therapy: Legislative process and product  

Microsoft Academic Search

The new Medicare benefit, medical nutrition therapy (MNT), came into effect January 2002[mdash ]the product of a lengthy legislative process. Over several years, evidence-based advocacy by groups such as the American Diabetic Association and the National Kidney Foundation led to a legislative product that was introduced and passed by Congress. More recently, the legislation entered an implementation process, including the

Mark E. Williams; Dolph Chianchiano

2002-01-01

380

Integrated Product and Process Design: Current Practices and Future Directions  

Microsoft Academic Search

The University of Florida's Integrated Product and Process Design (IPPD) program is an exemplary model of university-industry collaboration. IPPD features multidisciplinary teams of engineering and business students developing authentic products and processes for industry project sponsors. Each team is led by a faculty coach and is supported by a liaison engineer from the project sponsor. The program has flourished over

R. Keith Stanfill

381

Barnacle cement: An etchant for stainless steel 316L?  

Microsoft Academic Search

Localized corrosion of stainless steel beneath the barnacle-base is an unsolved issue for the marine industry. In this work, we clearly bring out for the first time the role of the barnacle cement in acting as an etchant, preferentially etching the grain boundaries, and initiating the corrosion process in stainless steel 316L. The investigations include structural characterization of the cement

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

2010-01-01

382

Process for the production of hydrogen peroxide  

DOEpatents

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

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

1997-09-02

383

Process for the production of hydrogen peroxide  

DOEpatents

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

Datta, Rathin (Chicago, IL); Randhava, Sarabjit S. (Evanston, IL); Tsai, Shih-Perng (Naperville, IL)

1997-01-01

384

Sweet sorghum processing for alcohol production  

SciTech Connect

Several processing techniques for producing ethanol from sweet sorghum were investigated. Fermentating chopped stalks yielded more ethanol than shredded sorghum or juice. Leaf removal prior to fermentation resulted in higher yields per unit feedstock. Removal of solids after fermentation yielded slightly more ethanol than solids removal before fermentation.

Schmulevich, I.; Coble, C.G.; Egg, R.P.

1983-12-01

385

Plasma Processing for Materials Production. Final Report.  

National Technical Information Service (NTIS)

A survey of thermal-plasma processing is made, with particular reference to the potential US market for increased electrification of industry. In both metallurgical and chemical applications the overwhelming need appears to be for large-scale industrial-p...

M. G. Down

1982-01-01

386

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

387

Integrated coke, asphalt and jet fuel production process and apparatus  

SciTech Connect

This patent describes a process and apparatus for the production of coke, asphalt and jet fuel from a feed of fossil fuels containing volatile carbon compounds. 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, J.Y.

1991-04-16

388

Nanocrystalline Tetracalcium Phosphate Cement  

Microsoft Academic Search

Calcium hydroxide cements can lack long-term stability and achieve sustained release by matrix-controlled diffusion of hydroxyl ions. Tetracalcium phosphate (TTCP) hydrolyzes slowly to form calcium hydroxide and a thin insoluble apatite layer that prevents further reaction. In this study, mechanical amorphization was used to create a setting calcium-hydroxide-releasing cement from TTCP. The effect of high-energy ball milling of TTCP on

U. Gbureck; J. E. Barralet; M. P. Hofmann

2004-01-01

389

Biomass chemicals production by thermochemical conversion. [Wacker synthesis, Eastman acetic anhydride process, Organosolv process kraft pulping  

Microsoft Academic Search

This paper reviews novel concepts for the production of chemicals by the thermochemical conversion of biomass. An engineering and economic analysis builds upon recent laboratory developments to provide a perspective of new process potentials and identifies areas requiring further investigation. Candidate processes fall into two categories: production of acetate esters, vinyl acetate and acetic anhydride by biomass gasification; and production

Klausmeier

1983-01-01

390

Run-to-run product quality control of batch processes  

Microsoft Academic Search

Batch processes have been increasingly used in the production of low volume and high value added products. Consequently, optimization\\u000a control in batch processes is crucial in order to derive the maximum benefit. In this paper, a run-to-run product quality\\u000a control based on iterative learning optimization control is developed. Moreover, a rigorous theorem is proposed and proven\\u000a in this paper, which

Li Jia; Ji-ping Shi; Da-shuai Cheng; Min-sen Chiu

2009-01-01

391

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.

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

2012-01-01

392

Measurement of Particle Size Distribution in Portland Cement Powder: Analysis of ASTM Round Robin Studies  

Microsoft Academic Search

A distribution of particle sizes or particle size distribution (PSD) is a fundamental characteristic of cement powder. Accurate PSDs are required in computational efforts to model the hydration process and it is an important practical issue for the cement industry. Presently, the only available standard method for measuring the PSD of cement, namely ASTM C115, is limited in scope, with

Chiara F. Ferraris; Vincent A. Hackley; Ana Ivelisse Avilés

2004-01-01

393

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.

394

Process development for microbial transglutaminase production  

Microsoft Academic Search

Transglutaminase (EC 2.3.2.13) catalyses in vitro cross-linking reactions in various proteins. This enzyme has been used in attempts to improve the functional properties of protein foods. Up to now, commercial transglutaminase has been obtained from animal tissues. The complicated separation and purification procedure results in an extremely high price of the enzyme, which hampers a wide application in food processing.

Yang Zhu

1997-01-01

395

Process for production desulfurized of synthesis gas  

Microsoft Academic Search

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

James K. Wolfenbarger; Mitri S. Najjar

1993-01-01

396

Process improvement exploration: mapping multimedia production process to CMMI-DEV  

NASA Astrophysics Data System (ADS)

Multimedia takes improvement of multiple computing technologies to incorporate data from a wide variety of resources, without involving users to know how and where the data is encoded and stored. By reason of Multimedia applications interact with users with numerous diverse techniques and incorporate into strong applications that greatly extend the range and strength of applications, the production process are often complicated and complex. Production of such applications requires both process- and product-based quality assurance. Apparently, there are no universally accepted technical production standards. Consequently, Multimedia applications have sometimes diminished the quality of the end product, increased costs, delayed completion and failure. The focus is on the mapping between the current practices of multimedia production process and one of universal process improvement framework, Capability Maturity Model Integration for Development (CMMI-DEV). It shows that how current practices of multimedia production process address the Engineering Process Areas of CMMI-DEV. For each of the relevant process areas, it then explores how current practices can contribute to achieve the specific goals of that process area. This is practical for organizations that have their plan-driven process based on the CMMI-DEV model and are planning to improve the current practices of multimedia production process or to assist organization to define an innovative multimedia production process cycle based on CMMI-DEV practices.

Lim, ChienWin; Kamaruddin, Noraida; Daud, Nor Izyani; Zainal Osman, Zosipha

2013-03-01

397

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

398

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

SciTech Connect

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

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

1997-09-01

399

An optimal production run time with imperfect production processes and allowable shortages  

Microsoft Academic Search

This paper develops a model to determine an optimal run time for a deteriorating production system under allowable shortage. It is assumed that the elapsed time until the production process shift is arbitrarily distributed. We show that there exists a unique optimal production run time to minimize the total relevant cost function. Finally, bounds for the optimal production run time

Kun-jen Chung; Kuo-lung Hou

2003-01-01

400

Engineering change request management in a new product development process  

Microsoft Academic Search

Purpose – The objective of this research was to compare the behavior of two methods of managing an engineering change request (ECR) process, namely, perform changes as they occur or in a batch. Design\\/methodology\\/approach – This comparison was accomplished by creating a computer model of a new product development (NPD) process and simulating ECR management. The model connects process design

Bhuiyan Nadia; Gatard Gregory; Thomson Vince

2006-01-01

401

Assembly Process Reengineering Applied to Production Line Balancing  

Microsoft Academic Search

With the analysis of the present condition and process reengineering of the transmission case assembly line, we can draw operation process chart, measure and record the necessary data from the various processes by the methods of the industrial engineering, such as the Principles of ECRS, Program Analysis Method and Production Line Balancing, etc. We can make a series of work

Ma Li-xin; Xie Hai-hong; Zhang Jian-bo

2009-01-01

402

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

403

Process for the production of maleic anhydride  

SciTech Connect

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

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

1986-06-24

404

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

405

Early-age monitoring of cement structures using FBG sensors  

NASA Astrophysics Data System (ADS)

With more and more broad applications of the cement-based structures such as neat cement paste, cement mortar and concrete in civil engineering, people hope to find out what their performances should like. The in-service performances of cement-based structures are highly affected by their hardening process during the early-age. But it is still a big problem for traditional sensors to be used to monitor the early curing of cement-based structures due to such disadvantages as difficulties to install sensors inside the concrete, limited measuring points, poor durability and interference of electromagnetic wave and so on. In this paper, according to the sensing properties of the Fiber Bragg Grating sensors and self-characters of the cement-based structures, we have successfully finished measuring and monitoring the early-age inner-strain and temperature changes of the neat cement paste, concrete with and without restrictions, mass concrete structures and negative concrete, respectively. Three types of FBG-based sensors have been developed to monitor the cement-based structures. Besides, the installation techniques and the embedding requirements of FBG sensors in cement-based structures are also discussed. Moreover, such kind of technique has been used in practical structure, 3rd Nanjing Yangtze Bridge, and the results show that FBG sensors are well proper for measuring and monitoring the temperature and strain changes including self-shrinkage, dry shrinkage, plastic shrinkage, temperature expansion, frost heaving and so on inside different cement-based structures. This technique provides us a new useful measuring method on early curing monitoring of cement-based structures and greater understanding of details of their hardening process.

Wang, Chuan; Zhou, Zhi; Zhang, Zhichun; Ou, Jinping

2006-04-01

406

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

407

Low velocity flexural impact behavior of AR glass fabric reinforced cement composites  

Microsoft Academic Search

Fabric–cement composites developed using the pultrusion production process have demonstrated impressive tensile and flexural properties. For instance fabric reinforced composites with bonded Alkali Resistant (AR) glass fabrics exhibit strain-hardening behavior, tensile strength in the range of 20–25MPa, and strain capacity of the order of 2–5% under static conditions. Properties of these composite systems were investigated under three point bending conditions

Deju Zhu; Mustafa Gencoglu; Barzin Mobasher

2009-01-01

408

Investigations of the bonding layer in commercial CVD coated cemented carbide inserts  

Microsoft Academic Search

The effects of processing parameters on the bonding layer structure between the cemented carbide substrate and the Al2O3 coating were investigated by depositing thick bonding layers under commercial production conditions. Different from the belief in the literature that the bonding layer is a cubic Ti(C,N,O) phase, titanium oxides were observed. Energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD) measurements were

Zhi-Jie Liu; Zi-Kui Liu; Charles McNerny; Pankaj Mehrotra; Aharon Inspektor

2005-01-01

409

Mud-to-cement technology converts industry practices  

SciTech Connect

Zonal isolation in the annulus of a producing well is the driving force behind the search for new cementing technology. A new process uses hydraulic blast furnace slag (BFS) to convert water-based drilling fluid into a cement, improving complete well bore isolation potential. In the past, Portland well cements have been one of the primary methods for establishing zonal isolation. Casing and cementing a well has been the most consistently effective way of negating communication between permeable reservoir sections. Zonal isolation is critical for fracture stimulating multiple reservoir zones and allows shut-off of unwanted migration from a gas cap or water zone. A weakness of conventional cementing, however, is obtaining a reliable seal at the borehole wall. Cementing jobs often are ineffective due to contamination of the cement by drilling fluids used earlier in the well. The development of mud-to-cement(MTC) techniques improved traditional methods. BFS combines fluid and solid properties to improve zonal isolation and casing support. The material also is low in cost, widely available, and simple to design and handle. Achieving a proper level of activation with slag material is fairly easy. Previous MTC processes used additives to adjust properties, and performance varied depending on well conditions.

Bell, S.

1993-09-01

410

Comparative efficiency assessments for a range of hydrogen production processes  

Microsoft Academic Search

Efficiencies, based on energy and exergy, are comparatively assessed for a wide range of hydrogen production processes, including processes which are •• hydrocarbon-based (steam-methane reforming and coal gasification),•• non-hydrocarbon-based (water electrolysis and thermochemical water decomposition), and•• integrated (steam-methane reforming linked to the non-hydrocarbon-based processes). A process simulation and analysis computer code is used throughout. Overall efficiencies, based on primary resource

M. A. Rosen; D. S. Scott

1998-01-01

411

ULTRA-LIGHTWEIGHT CEMENT  

SciTech Connect

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

Fred Sabins

2001-10-23

412

Cement composition and method of cement casing in a well  

SciTech Connect

A novel cement composition for the preparation of a novel aqueous slurry useful in cementing casing in the borehole of a well comprising cement, a hydroxyethylcellulose ether having a critical viscosity or a mixture of a hydroxyethylcellulose ether having a critical viscosity and of a hydroxypropylcellulose ether having a critical viscosity and a dispersant.

Baker, W.S.; Harrison, J.J.

1984-07-31

413

Cement composition and method of cement casing in a well  

SciTech Connect

A novel cement composition for the preparation of a novel aqueous slurry useful in cementing casing in the borehole of a well comprising cement, a hydroxyethylcellulose ether or a mixture of a hydroxyethylcellulose ether and a hydroxypropylcellulose ether a polysaccharide produced as a result of microbial action and a dispersant.

Baker, W.S.; Harrison, J.J.

1984-07-31

414

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

415

Lightweight cementing program increases profit from Kansas oil field  

SciTech Connect

This paper reports that single-stage, lightweight cementing in a Kansas operation improved the cement bond across a permeable oil/water sand. Additionally, pipe movement after pumping helped bond quality by preventing the slurry from beginning its transition time. This delay allowed continued transmission of hydrostatic pressure against the formation. In 1991, OXY USA Inc. completed 12 wells in the Ray field in Kansas. All wells were drilled to the Reagan sand. The sand has a distinct water/oil contact, strong water drive, and good permeability. Because of poor cement bonding across the Reagan, two-stage conventional cementing in the first eight wells did not effectively prevent excessive water production. Some of these wells had to have remedial cement squeezes and be reperforated. This work increased completion costs by about $15,000/well.

McCalmont, A.J. (OXY USA Inc., Wichita KS (United States)); Matthews, B.; Crook, R. (Halliburton Services, Duncan, OK (United States))

1992-06-29

416

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

417

A descriptive model of the consumer co-production process  

Microsoft Academic Search

Purpose  This article presents a model of consumer engagement in co-production.\\u000a \\u000a \\u000a \\u000a Method  A theoretical paper which develops a five-stage dynamic model of consumer involvement in co-production.\\u000a \\u000a \\u000a \\u000a Results and Conclusions  The article discusses the basic linkages between co-production and customization and presents co-production as a dynamic process\\u000a which is composed of five distinct stages. It also specifies five distinct phases of the production activity

Michael Etgar

2008-01-01

418

Advanced Cements for Geothermal Wells.  

National Technical Information Service (NTIS)

Using the conventional well cements consisting of the calcium silicate hydrates and calcium aluminum silicate hydrates for the integrity of geothermal wells, the serious concern confronting the cementing industries was their poor performance in mechanical...

T. Sugama

2006-01-01

419

Lime Silico-Phosphate Cement.  

National Technical Information Service (NTIS)

A quick setting lime silico-phosphate cement prepared by reacting Wollastonite (CaSiO3) and buffered phosphoric acid is described. The cement has particular utility in highway patching operations. (Author)

C. E. Semler

1972-01-01

420

The hydration of dental cements.  

PubMed

A study was made of the hydration of dental cements, water being classified as "non-evaporable" and "evaporable". The ratio of these two types of water was found to vary greatly among different cement types, being lesser in zinc oxide and ionic polymer cements and greater in ion-leachable glass and phosphoric acid cements. The cement with the least "non-evaporable" water, i.e., showing least hydration (the zinc polycarboxylate cement), had the lowest strength and modulus and the greatest deformation at failure. A linear relationship was found to exist between strength and the degree of hydration of dental cements. All the cements were found to become more highly hydrated and stronger as they aged. PMID:284040

Wilson, A D; Paddon, J M; Crisp, S

1979-03-01

421

Behavior of ordinary Portland cement during the stabilization/solidification of synthetic heavy metal sludge: Macroscopic and microscopic aspects  

SciTech Connect

Chromium and/or zinc hydroxide sludges were mixed at variable proportions with OPC, in order to evaluate the macroscopic and microscopic effects caused by the waste on the cement hydration process. Initial setting time, heat production during hydration, leaching characteristics and microstructure of the samples were investigated using varied techniques. For zinc hydroxide sludge, hydration was stopped after a few minutes, because of the precipitation of a solid hydrated phase. Since the sludge:cement ratio remains under 2--3:1, chromium hydroxide sludge accelerated the cement hydration. For higher ratios, hydration was hindered. Some microstructural modifications have been detected, such as the possible formation of a U-phase analog, related to the presence of chromate ions in the sludge. The influence of the oxidation degree of chromium on its fixation in the matrix is discussed.

Diet, J.N.; Moszkowicz, P. [Inst. National des Sciences Appliquees de Lyon, Villeurbanne (France). Lab d`Analyse Environnementale des Procedes et des Systemes Industriels; Sorrentino, D. [Lafarge Lab. Central de Recherche, St. Quentin Fallavier (France)

1998-12-31

422

Oxygen Production Processes on the Moon: An Overview (Abstract Only).  

National Technical Information Service (NTIS)

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 t...

L. A. Taylor W. D. Carrier

1991-01-01

423

Producibility and Production Aspects of the Market Analysis Process.  

National Technical Information Service (NTIS)

This publication reports on the degree of emphasis accorded to producibility and production issues early in the acquisition process within the Army Materiel Command and the Training and Doctrine Command. Data and information for the report was acquired du...

J. W. CLark

1989-01-01

424

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

425

Ajmalicine Production by Catharanthus Roseus: Process Operation and Modelling.  

National Technical Information Service (NTIS)

Contents: Introduction: large scale cultivation of plant cells; Factors involved in the production of ajmalicine by Catharanthus roseus: scaleup and process operation; Kinetics of ajmalicine formation by Catharanthus roseus; A simple structured model for ...

J. E. Schlatmann

1995-01-01

426

Recombinant Protein Production and Insect Cell Culture and Process.  

National Technical Information Service (NTIS)

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 pr...

G. Spaulding T. Prewett T. Goodwin K. Francis A. Andrews

1993-01-01

427

Processing of Vietnamese Essential Oils and Related Natural Products.  

National Technical Information Service (NTIS)

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

R. Gupta

1990-01-01

428

Geothermal Cementing - The State of the Art  

SciTech Connect

Much emphasis today is being placed on the drilling and completion of steam wells. Success or failure depends greatly on the cementing process, which requires not only the selection of competent and durable materials but also the complete understanding of placement techniques. Immobile muds, crooked holes, lost circulation, poor centralization, and the inability to move pipe are some of the major areas which contribute to good or bad results. This presentation covers a ''state of the art'' of the various techniques, materials, and equipment being used in cementing steam wells in the US and Mexico.

Shryock, S. H.; Smith, D. K.

1981-01-01

429

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

430

Repeated fed-batch process for improving lovastatin production  

Microsoft Academic Search

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

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

2000-01-01

431

Exclusive processes of charmonium production and charmonium wave functions  

SciTech Connect

Results obtained by studying the properties of the leading-twist wave functions for the S- and P-wave states of charmonia are presented. Wave-function models that can be used to calculate various processes involving the production of these mesons were constructed on the basis of these investigations. Calculations for some exclusive processes of charmonium production were performed within the models in question.

Braguta, V. V., E-mail: braguta@mail.ru; Likhoded, A. K., E-mail: Anatolii.Likhoded@ihep.ru; Luchinsky, A. V., E-mail: Alexey.Luchinsky@ihep.ru [Institute for High Energy Physics (Russian Federation)

2012-01-15

432

Mining manufacturing data for discovery of high productivity process characteristics.  

PubMed

Modern manufacturing facilities for bioproducts are highly automated with advanced process monitoring and data archiving systems. The time dynamics of hundreds of process parameters and outcome variables over a large number of production runs are archived in the data warehouse. This vast amount of data is a vital resource to comprehend the complex characteristics of bioprocesses and enhance production robustness. Cell culture process data from 108 'trains' comprising production as well as inoculum bioreactors from Genentech's manufacturing facility were investigated. Each run constitutes over one-hundred on-line and off-line temporal parameters. A kernel-based approach combined with a maximum margin-based support vector regression algorithm was used to integrate all the process parameters and develop predictive models for a key cell culture performance parameter. The model was also used to identify and rank process parameters according to their relevance in predicting process outcome. Evaluation of cell culture stage-specific models indicates that production performance can be reliably predicted days prior to harvest. Strong associations between several temporal parameters at various manufacturing stages and final process outcome were uncovered. This model-based data mining represents an important step forward in establishing a process data-driven knowledge discovery in bioprocesses. Implementation of this methodology on the manufacturing floor can facilitate a real-time decision making process and thereby improve the robustness of large scale bioprocesses. PMID:20416347

Charaniya, Salim; Le, Huong; Rangwala, Huzefa; Mills, Keri; Johnson, Kevin; Karypis, George; Hu, Wei-Shou

2010-04-21

433

Measuring knowledge in the new product development process  

Microsoft Academic Search

Purpose – To present a measurement framework to capture the importance of the use of knowledge within the new product development (NPD) process. Design\\/methodology\\/approach – A literature review enabled 200 product development measures to be compiled. These were categorised into six dimensions: stakeholder contribution, operating context, reuse, invention, exploitation, and NPD performance. Four companies applied selected measures and assessed the

Fiona Lettice; Norman Roth; Ingo Forstenlechner

2006-01-01

434

Size, cost, and productivity in the meat processing industries  

Microsoft Academic Search

Technology and technical change in the meat processing industries are examined in a cost function framework. Consistent with other studies, we find productivity growth rates to have declined in the past several decades. Nevertheless, growth has consistently been positive and has responded only modestly to the business cycle and to capital prices. Productivity-induced downshifts in unit cost curves have boosted

Yin Xia; Steven Buccola

2002-01-01

435

Fuzzy analytical hierarchy process in new product screening  

Microsoft Academic Search

Recently, Calantone, Di Benedetto, and Schmidt (2) presented an Analytic Hierarchy Process (Am) modeling approach to new product screening. The illustration of this approach is an example of a decision support model that seeks to aid managers in selecting new product ideas to pursue. In this paper we improve upon this initial AHP model using a \\

Kamal Smimou; Suresh Bhatt; Darren W. Dahl

2001-01-01

436

NIR spectroscopy for determining soy contents in processed meat products  

Technology Transfer Automated Retrieval System (TEKTRAN)

Soy products such as soy concentrate, soy protein and soy grits are used as a meat extender in processed meat products to improve meat texture. However, soy allergies are one of the common food allergies, especially in infants and young children, and can be mild to life-threatening. The United State...

437

Process development for the mass production of Ehrlichia ruminantium  

Microsoft Academic Search

This work describes the optimization of a cost-effective process for the production of an inactivated bacterial vaccine against heartwater and the first attempt to produce the causative agent of this disease, the rickettsia Ehrlichia ruminantium (ER), using stirred tanks. In vitro, it is possible to produce ER using cultures of ruminant endothelial cells. Herein, mass production of these cells was

Isabel Marcelino; Marcos F. Q. Sousa; Célia Veríssimo; António E. Cunha; Manuel J. T. Carrondo; Paula M. Alves

2006-01-01

438

A Macro Process Model for Product Innovation Using TRIZ  

Microsoft Academic Search

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

Tan Runhua

439

Market Feedback and Team Commitment in Radical Product Innovation Process  

Microsoft Academic Search

Previous research has considered how exploratory market learning processes moderate market and technological uncertainty in radical product development. Scholars argue that new product development (NPD) teams may increase the chances of success of radically new projects by acquiring, assimilating and implementing new information from market feedback. However, research has not tackled how information is assimilated by the NPD team and

Luca Berchicci; Christopher Tucci

2008-01-01

440

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

Microsoft Academic Search

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

DOUGLAS C. MONTGOMERY

1992-01-01

441

Carbonate diagenesis in Quaternary beachrock of Uyombo, Kenya: Sequences of processes and coexistence of heterogenic products  

Microsoft Academic Search

The calcareous quartz sandstone contains a variety of carbonate cements; these and the biogenic carbonate particles have been preserved and altered in various ways.Several inherited submarine intra-particle cements are followed by a submarine high-Mg calcite palisade cement, then by a meteoric low-Mg calcite blocky cement, and finally by a submarine aragonite spherulitic cement. While the sequence of cementation is clearly

Johannes H. Schroeder

1979-01-01

442

Research of magnesium phosphosilicate cement  

Microsoft Academic Search

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

Zhu Ding

2005-01-01

443

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

444

Respiratory tract mortality in cement workers: a proportionate mortality study  

PubMed Central

Background The evidence regarding the association between lung cancer and occupational exposure to cement is controversial. This study investigated causes of deaths from cancer of respiratory tract among cement workers. Methods The deaths of the Greek Cement Workers Compensation Scheme were analyzed covering the period 1969-1998. All respiratory, lung, laryngeal and urinary bladder cancer proportionate mortality were calculated for cement production, maintenance, and office workers in the cement industry. Mortality from urinary bladder cancer was used as an indirect indicator of the confounding effect of smoking. Results Mortality from all respiratory cancer was significantly increased in cement production workers (PMR?=?1.91; 95% CI 1.54 to 2.33). The proportionate mortality from lung cancer was significantly elevated (PMR?=?2.05; 95% CI 1.65 to 2.52). A statistically significant increase in proportionate mortality due to respiratory (PMR?=?1.7; 95% CI 1.2 to 2.34). and lung cancer (PMR?=?1.67;95% CI?=?1.15-2.34) among maintenance workers has been observed. The PMR among the three groups of workers (production, maintenance, office) did differ significantly for lung cancer (p?=?0.001), while the PMR for urinary bladder cancer found to be similar among the three groups of cement workers. Conclusion Cement production, and maintenance workers presented increased lung and respiratory cancer proportionate mortality, and this finding probably cannot be explained by the confounding effect of smoking alone. Further research including use of prospective cohort studies is needed in order to establish a causal association between occupational exposure to cement and risk of lung cancer.

2012-01-01

445

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

PubMed

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

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

2005-04-01

446

Methodical approach to increase productivity and reduce lead time in assembly and production-logistic processes  

Microsoft Academic Search

The introduced methodical approach connects Value Stream Mapping (VSM) and Methods-Time Measurement (MTM) and offers new distinct advantages to reduce lead time and increase productivity based on lean principles and standardised processes. The mutually aligned design and improvement of assembly and (production) logistic processes takes either the workplaces, their surroundings and the supply areas as well as the overall value

P. Kuhlang; T. Edtmayr; W. Sihn

2011-01-01

447

Evaluating the environmental impact of products and production processes: a comparison of six methods  

Microsoft Academic Search

The desire of environmentally-conscious consumers and manufacturers to choose more environmentally benign products and processes has led to the development of life cycle assessment (LCA) and design for environment (DfE). In both of these areas, attention has focused initially on the development of inventories of emissions and raw materials consumption for particular products and processes. A number of methods for

Edgar G. Hertwich; William S. Pease; Catherine P. Koshland

1997-01-01

448

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

449

Production of concentrated kiwifruit juice by integrated membrane process  

Microsoft Academic Search

The concentration of fruit juices is industrially performed in order to reduce storage, packaging, handling and shipping costs. This paper describes the research efforts to develop and optimise an integrated membrane process, on laboratory scale, for the production of concentrated kiwifruit juice as alternative to the traditional vacuum evaporation. Fresh depectinated kiwifruit juice was previously clarified by ultrafiltration (UF) process.

A. Cassano; B. Jiao; E. Drioli

2004-01-01

450

Integrated PV-thermal panel and process for production  

Microsoft Academic Search

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

Jarnagin

1986-01-01

451

Recycling of thermosetting plastic waste from electronic component production processes  

Microsoft Academic Search

This paper describes the recycling of the mold waste from printed wiring boards (PWBs) and the molding resin used for IC packages, which are the main types of thermosetting plastic waste produced in the electronic component production processes. A practical process for pulverizing the PWB waste and separating the resulting powder into a copper rich powder and a powder consisting

S. Yokoyama; M. Iji

1995-01-01

452

Revising the master production schedule in sequence dependent processes  

Microsoft Academic Search

Revising the master production schedule (MPS) in a rolling planning horizon environment to improve plant performance is critical in process industries with sequence dependent changeovers. Plant performance is defined in terms of process changeover time, total shortages, and finished goods inventory. Two heuristics for revising the MPS are introduced and tested against a rolling horizon MPS that does not take

James A. Hill; William L. Berry; David A. Schilling

2003-01-01

453

Multilayers process modeling for complex machinery products collaborative design  

Microsoft Academic Search

Collaborative model and process model for complex machinery products collaborative design are studied in this paper. The authors propose a layer collaborative model, which is used to describe the layer collaborative process in complex machinery design firstly. It contains design layer dimension, design objective dimension, design cycle\\/period dimension and design constraint dimension. The model is described by state-space method and

Yin-zhang Guo; Jian-chao Zeng

2010-01-01

454

Summary report: Economic feasibility studies of alcohol fuel production processes  

Microsoft Academic Search

In 1983 SERI awarded six subcontracts to four engineering firms to conduct technical and economic feasibility studies of processes to convert lignocellulosic feedstocks into premium fuels (methanol and ethanol). In this report general conclusions are drawn about the status of alcohol fuels production from cellulosic feedstocks and detailed conclusions about the status, economics, research needs, and process steps. Stone and

J. D. Wright; T. Milne; M. E. Karpuk; S. Isaacs; W. Hoagland

1986-01-01

455

Sorption-enhanced reaction process for hydrogen production  

Microsoft Academic Search

A novel concept called Sorption Enhanced Reaction Process (SERP) for hydrogen production by steam-methane reformation (SMR) reaction uses a fixed packed column of an admixture of an SMR catalyst and a chemisorbent to remove carbon dioxide selectively from the reaction zone. The chemisorbent is periodically generated by using the principles of pressure swing adsorption. The SERP process steps allow direct

J. R. Hufton; S. Mayorga; S. Sircar

1999-01-01

456

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...

457

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