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Sample records for mass concrete mixture

  1. The development of a lower heat concrete mixture for mass concrete placement conditions

    NASA Astrophysics Data System (ADS)

    Crowley, Aaron Martin

    The hydration process of portland cement (PC) is exothermic; therefore, the thermal behavior of concrete has to be taken into consideration when placed in a large mass. The research presented involves a Tennessee Department of Transportation (TDOT) Class S (seal) portland cement concrete (PCC) which is used as a foundation seal during construction of bridge abutments and piers. A Class S PCC mixture meeting the 2006 TDOT specifications has the potential to generate excessive amounts of heat and induce thermal cracking in structural elements. The purpose of the study is to reduce the heat generation of a Class S PCC while maintaining adequate values of other engineering properties. Due to the possibility of underwater placement of a Class S PCC, reduction in the total cementing materials content were not considered in this study. Five candidate mixtures were used to compare against a typical TDOT Class S mixture. The five candidate Class S-LH (lower heat) mixtures were 45, 60, 70% Grade 120 slag substitutions for PC as well as two ternary mixtures containing Grade 120 slag and Class F fly ash. Ten batches of each mixture were produced. All plastic and hardened properties met TDOT 604.03 Class S requirements for analytical comparison. The 70% Grade 120 slag Class S-LH mixture was analytically superior for all hardened properties and at reducing heat generation. Since the 70% Grade 120 slag Class S-LH mixture proved to be superior in laboratory conditions; it was selected for further evaluation in the field testing portion of the research. The 70% Grade 120 slag mixture produced a significantly lower maximum temperature as well as a significantly lower maximum differential temperature than a TDOT Class S mixture with 20% Class C fly ash in side-by-side 18 cubic yard cube field placements. Research results and literature recommend that engineers should decide when mass concrete conditions are appropriate during construction practices. When mass concrete conditions are

  2. Simulation of Mass Transfer of Calcium in Concrete by the Lattice Kinetic Scheme for a Binary Miscible Fluid Mixture

    NASA Astrophysics Data System (ADS)

    Yoshino, Masato; Murayama, Toshiro; Matsuzaki, Akihiro; Hitomi, Takashi

    The lattice kinetic scheme (LKS) for a binary miscible fluid mixture was applied to the simulation of the mass transfer of calcium in concrete. Cement paste, a major component of concrete, is a porous medium with a complicated three-dimensional geometry. The structure of the model concrete was selected on the basis of experimental data obtained by high-intensity X-ray computed tomography. The LKS, an improved version of the original lattice Boltzmann method, was used to save computational memory and to maintain numerical stability. First, an unsteady convection-diffusion problem was examined, and the accuracy of the method and the error norms with various lattice resolutions were investigated. Next, the problem of the calcium current in concrete was simulated. Pressure drops in the concrete were calculated for various Reynolds numbers, and the results were compared with those of an empirical equation based on experimental data. Also, velocity fields and concentration profiles were obtained at a pore scale for a structure with inhomogeneous mass diffusivities. These simulations showed that the present method might be useful for predicting calcium leaching in concrete from the microscopic point of view.

  3. Concrete mixture characterization. Cementitious barriers partnership

    SciTech Connect

    Langton, C.; Protiere, Yannick

    2014-12-01

    This report summarizes the characterization study performed on two concrete mixtures used for radioactive waste storage. Both mixtures were prepared with approximately 425 kg of binder. The testing protocol mostly focused on determining the transport properties of the mixtures; volume of permeable voids (porosity), diffusion coefficients, and water permeability were evaluated. Tests were performed after different curing durations. In order to obtain data on the statistical distribution of transport properties, the measurements after 2 years of curing were performed on 10+ samples. Overall, both mixtures exhibited very low tortuosities and permeabilities, a direct consequence of their low water-to-binder ratio and the use of supplementary cementitious materials. The data generated on 2-year old samples showed that porosity, tortuosity and permeability follow a normal distribution. Chloride ponding tests were also performed on test samples. They showed limited chloride ingress, in line with measured transport properties. These test results also showed that both materials react differently with chloride, a consequence of the differences in the binder chemical compositions.

  4. 27. View of underside of ninth bridge, showing concrete mixture, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    27. View of underside of ninth bridge, showing concrete mixture, view to the NW. - Vicksburg National Military Park Roads & Bridges, Melan Arch Bridges, Spanning various tributaries at Confederate Avenue, Vicksburg, Warren County, MS

  5. A Statistical Approach to Optimizing Concrete Mixture Design

    PubMed Central

    Alghamdi, Saeid A.

    2014-01-01

    A step-by-step statistical approach is proposed to obtain optimum proportioning of concrete mixtures using the data obtained through a statistically planned experimental program. The utility of the proposed approach for optimizing the design of concrete mixture is illustrated considering a typical case in which trial mixtures were considered according to a full factorial experiment design involving three factors and their three levels (33). A total of 27 concrete mixtures with three replicates (81 specimens) were considered by varying the levels of key factors affecting compressive strength of concrete, namely, water/cementitious materials ratio (0.38, 0.43, and 0.48), cementitious materials content (350, 375, and 400 kg/m3), and fine/total aggregate ratio (0.35, 0.40, and 0.45). The experimental data were utilized to carry out analysis of variance (ANOVA) and to develop a polynomial regression model for compressive strength in terms of the three design factors considered in this study. The developed statistical model was used to show how optimization of concrete mixtures can be carried out with different possible options. PMID:24688405

  6. The optimization of concrete mixtures for use in highway applications

    NASA Astrophysics Data System (ADS)

    Moini, Mohamadreza

    Portland cement concrete is most used commodity in the world after water. Major part of civil and transportation infrastructure including bridges, roadway pavements, dams, and buildings is made of concrete. In addition to this, concrete durability is often of major concerns. In 2013 American Society of Civil Engineers (ASCE) estimated that an annual investment of 170 billion on roads and 20.5 billion for bridges is needed on an annual basis to substantially improve the condition of infrastructure. Same article reports that one-third of America's major roads are in poor or mediocre condition [1]. However, portland cement production is recognized with approximately one cubic meter of carbon dioxide emission. Indeed, the proper and systematic design of concrete mixtures for highway applications is essential as concrete pavements represent up to 60% of interstate highway systems with heavier traffic loads. Combined principles of material science and engineering can provide adequate methods and tools to facilitate the concrete design and improve the existing specifications. In the same manner, the durability must be addressed in the design and enhancement of long-term performance. Concrete used for highway pavement applications has low cement content and can be placed at low slump. However, further reduction of cement content (e.g., versus current specifications of Wisconsin Department of Transportation to 315-338 kg/m 3 (530-570 lb/yd3) for mainstream concrete pavements and 335 kg/m3 (565 lb/yd3) for bridge substructure and superstructures) requires delicate design of the mixture to maintain the expected workability, overall performance, and long-term durability in the field. The design includes, but not limited to optimization of aggregates, supplementary cementitious materials (SCMs), chemical and air-entraining admixtures. This research investigated various theoretical and experimental methods of aggregate optimization applicable for the reduction of cement content

  7. The optimization of concrete mixtures for use in highway applications

    NASA Astrophysics Data System (ADS)

    Moini, Mohamadreza

    Portland cement concrete is most used commodity in the world after water. Major part of civil and transportation infrastructure including bridges, roadway pavements, dams, and buildings is made of concrete. In addition to this, concrete durability is often of major concerns. In 2013 American Society of Civil Engineers (ASCE) estimated that an annual investment of 170 billion on roads and 20.5 billion for bridges is needed on an annual basis to substantially improve the condition of infrastructure. Same article reports that one-third of America's major roads are in poor or mediocre condition [1]. However, portland cement production is recognized with approximately one cubic meter of carbon dioxide emission. Indeed, the proper and systematic design of concrete mixtures for highway applications is essential as concrete pavements represent up to 60% of interstate highway systems with heavier traffic loads. Combined principles of material science and engineering can provide adequate methods and tools to facilitate the concrete design and improve the existing specifications. In the same manner, the durability must be addressed in the design and enhancement of long-term performance. Concrete used for highway pavement applications has low cement content and can be placed at low slump. However, further reduction of cement content (e.g., versus current specifications of Wisconsin Department of Transportation to 315-338 kg/m 3 (530-570 lb/yd3) for mainstream concrete pavements and 335 kg/m3 (565 lb/yd3) for bridge substructure and superstructures) requires delicate design of the mixture to maintain the expected workability, overall performance, and long-term durability in the field. The design includes, but not limited to optimization of aggregates, supplementary cementitious materials (SCMs), chemical and air-entraining admixtures. This research investigated various theoretical and experimental methods of aggregate optimization applicable for the reduction of cement content

  8. USINT. Heat and Mass Transfer In Concrete

    SciTech Connect

    Eyberger, L.R.

    1989-12-01

    USINT was developed to model the thermal response of concrete to very high heating rates such as might occur from sodium spills on concrete surfaces in a breeder reactor. The major phenomena treated are conductive energy transport; chemical decomposition of concrete; and two-phase, three-component heat and mass transfer of the decomposition products: steam, liquid water, and carbon dioxide. The USINT model provides for porosity to increase as water and carbon-dioxide are formed from the concrete. The concrete is treated generally as divided into two basic regions, wet and dry. In the wet region, steam, carbon-dioxide, and liquid water may co-exist, but in the dry region, there is no liquid water. There is also the possibility of a third region in which there is only liquid water and no gases.

  9. USINT. Heat and Mass Transfer in Concrete

    SciTech Connect

    Beck, J.V.; Knight, R.L.

    1989-12-01

    USINT was developed to model the thermal response of concrete to very high heating rates such as might occur from sodium spills on concrete surfaces in a breeder reactor. The major phenomena treated are conductive energy transport; chemical decomposition of concrete; and two-phase, three-component heat and mass transfer of the decomposition products: steam, liquid water, and carbon dioxide. The USINT model provides for porosity to increase as water and carbon-dioxide are formed from the concrete. The concrete is treated generally as divided into two basic regions, wet and dry. In the wet region, steam, carbon-dioxide, and liquid water may co-exist, but in the dry region, there is no liquid water. There is also the possibility of a third region in which there is only liquid water and no gases.

  10. An investigation of waste foundry sand in asphalt concrete mixtures.

    PubMed

    Bakis, Recep; Koyuncu, Hakan; Demirbas, Ayhan

    2006-06-01

    A laboratory study regarding the reuse of waste foundry sand in asphalt concrete production by replacing a certain portion of aggregate with WFS was undertaken. The results showed that replacement of 10% aggregates with waste foundry sand was found to be the most suitable for asphalt concrete mixtures. Furthermore, the chemical and physical properties of waste foundry sand were analysed in the laboratory to determine the potential effect on the environment. The results indicated that the investigated waste foundry sand did not significantly affect the environment around the deposition PMID:16784170

  11. Variability in properties of Salado Mass Concrete

    SciTech Connect

    Wakeley, L.D.; Harrington, P.T.; Hansen, F.D.

    1995-08-01

    Salado Mass Concrete (SMC) has been developed for use as a seal component in the Waste Isolation Pilot Plant. This concrete is intended to be mixed from pre-bagged materials, have an initial slump of 10 in., and remain pumpable and placeable for two hours after mixing. It is a mass concrete because it will be placed in monoliths large enough that the heat generated during cement hydration has the potential to cause thermal expansion and subsequent cracking, a phenomenon to avoid in the seal system. This report describes effects on concrete properties of changes in ratio of water to cement, batch size, and variations in characteristics of different lots of individual components of the concrete. The research demonstrates that the concrete can be prepared from laboratory-batched or pre-bagged dry materials in batches from 1.5 ft{sup 3} to 5.0 yd{sup 3}, with no chemical admixtures other than the sodium chloride added to improve bonding with the host rock, at a water-to-cement ratio ranging from 0.36 to 0.42. All batches prepared according to established procedures had adequate workability for at least 1.5 hours, and achieved or exceeded the target compressive strength of 4500 psi at 180 days after casting. Portland cement and fly ash from different lots or sources did not have a measurable effect on concrete properties, but variations in a shrinkage-compensating cement used as a component of the concrete did appear to affect workability. A low initial temperature and the water-reducing and set-retarding functions of the salt are critical to meeting target properties.

  12. Determination of test methods for the prediction of the behavior of mass concrete

    NASA Astrophysics Data System (ADS)

    Ferraro, Christopher C.

    Hydration at early ages results from chemical and physical processes that take place between Portland cement and water, and is an exothermic process. The resultant heat evolution and temperature rise for massive concrete placements can be so great that the temperature differentials between the internal concrete core and outer concrete stratum can cause cracking due to thermal gradients. Accurate prediction of temperature distribution and stresses in mass concrete is needed to determine if a given concrete mixture design may have problems in the field, so that adjustments to the design can be made prior to its use. This research examines calorimetric, strength, and physical testing methods in an effort to predict the thermal and physical behavior of mass concrete. Four groups of concrete mixture types containing different cementitious materials are examined. One group contains Portland cement, while the other three groups incorporate large replacements of supplementary cementitious materials: granulated blast furnace slag, fly ash, and a ternary blend (combining Portland cement, fly ash, and slag).

  13. Mixtures of Ultracold Fermions with Unequal Masses

    NASA Astrophysics Data System (ADS)

    de Melo, Carlos A. R. Sa

    2008-05-01

    The quantum phases of ultracold fermions with unequal masses are discussed in continuum and lattice models for a wide variety of mixtures which exhibit Feshbach resonances, e.g., mixtures of ^6Li and ^40K. The evolution of superfluidity from the Bardeen-Cooper-Schrieffer (BCS) to the Bose-Einstein condensation (BEC) regime in the continuum is analyzed as a function of scattering parameter, population imbalance and mass anisotropy. In the continuum case, regions corresponding to normal, phase-separated or coexisting uniform-superfluid/excess-fermion phases are identified and the possibility of topological phase transitions is discussed [1]. For optical lattices, the phase diagrams as a function of interaction strength, population imbalance, filling fraction and tunneling parameters are presented [2]. In addition to the characteristic phases of the continuum, a series of insulating phases emerge in the phase diagrams of optical lattices, including a Bose-Mott insulator (BMI), a Fermi-Pauli insulator (FPI), a phase-separated BMI/FPI mixture, and a Bose-Fermi checkerboard (BFC) phase. Lastly, the effects of harmonic traps and the emergence of unusual shell structures are discussed for mixtures of fermions with unequal masses. [1] M. Iskin, and C. A. R. S' a de Melo, Phys. Rev. Lett 97, 100404 (2006); [2] M. Iskin, and C. A. R. S' a de Melo, Phys. Rev. Lett. 99, 080403 (2007).

  14. Reuse of municipal solid wastes incineration fly ashes in concrete mixtures.

    PubMed

    Collivignarelli, Carlo; Sorlini, Sabrina

    2002-01-01

    This study is aimed at assessing the feasibility of concrete production using stabilized m.s.w. (municipal solid waste) incineration fly ashes in addition to natural aggregates. The tested fly ashes were washed and milled, then stabilized by a cement-lime process and finally were reused as a "recycled aggregate" for cement mixture production, in substitution of a natural aggregate (with dosage of 200-400 kg m(-3)). These mixtures, after curing, were characterized with conventional physical-mechanical tests (compression, traction, flexure, modulus of elasticity, shrinkage). In samples containing 200 kg(waste) m(-3)(concrete), a good compressive strength was achieved after 28 days of curing. Furthermore, concrete leaching behavior was evaluated by means of different leaching tests, both on milled and on monolithic samples. Experimental results showed a remarkable reduction of metal leaching in comparison with raw waste. In some cases, similar behavior was observed in "natural" concrete (produced with natural aggregates) and in "waste containing" concrete.

  15. Influence of roofing shingles on asphalt concrete mixture properties. Final report, 1992-1993

    SciTech Connect

    Newcomb, D.; Stroup-Gardiner, M.; Weikle, B.; Drescher, A.

    1993-06-01

    The objective of the study was to evaluate the use of waste shingles from manufacturing and roof reconstruction projects in hot mix asphalt concrete mixtures. In dense-graded asphalt mixtures, it was hypothesized that the waste material might serve as an extender for the new asphalt in the mix as well as a fiber reinforcement. In the stone mastic asphalt (SMA), it could serve as the binder stiffener typically used to prevent the asphalt from draining out of these types of mixtures.

  16. Effect of the Key Mixture Parameters on Shrinkage of Reactive Powder Concrete

    PubMed Central

    Zubair, Ahmed

    2014-01-01

    Reactive powder concrete (RPC) mixtures are reported to have excellent mechanical and durability characteristics. However, such concrete mixtures having high amount of cementitious materials may have high early shrinkage causing cracking of concrete. In the present work, an attempt has been made to study the simultaneous effects of three key mixture parameters on shrinkage of the RPC mixtures. Considering three different levels of the three key mixture factors, a total of 27 mixtures of RPC were prepared according to 33 factorial experiment design. The specimens belonging to all 27 mixtures were monitored for shrinkage at different ages over a total period of 90 days. The test results were plotted to observe the variation of shrinkage with time and to see the effects of the key mixture factors. The experimental data pertaining to 90-day shrinkage were used to conduct analysis of variance to identify significance of each factor and to obtain an empirical equation correlating the shrinkage of RPC with the three key mixture factors. The rate of development of shrinkage at early ages was higher. The water to binder ratio was found to be the most prominent factor followed by cement content with the least effect of silica fume content. PMID:25050395

  17. Code System to Calculate Heat and Mass Transfer In Concrete

    1999-05-26

    Version 00 This version is designated USINTC and was developed to model the thermal response of concrete to very high heating rates such as might occur from sodium spills on concrete surfaces in a breeder reactor. The major phenomena treated are conductive energy transport; chemical decomposition of concrete; and two-phase, three-component heat and mass transfer of the decomposition products: steam, liquid water, and carbon dioxide. The USINT model provides for porosity to increase as watermore » and carbon-dioxide are formed from the concrete. The concrete is treated generally as divided into two basic regions, wet and dry. In the wet region, steam, carbon-dioxide, and liquid water may co-exist, but in the dry region, there is no liquid water. There is also the possibility of a third region in which there is only liquid water and no gases.« less

  18. Influence of mineral aggregates on the rheological properties of concrete mixture

    NASA Astrophysics Data System (ADS)

    Klovas, A.; Daukšys, M.

    2015-04-01

    The aim of this research was to determine how the change of concrete mixture constituents: concentration of fine and coarse aggregate as well as the amount of fine particles, not exceeding 0.25 mm, influence concrete mixture's rheological properties. Firstly, inner- concentration of fine aggregate (sand, fraction of 0/1 and 0/4) was changed. Secondly, coarse aggregate (gravel, fraction of 4/16) concentration was changed and finally, the amount of fine particles was changed. Results have shown that with the increase of sand (fraction of 0/1) quantity, the plastic viscosity also increased. On the other hand, yield stress, at the beginning decreased, but eventually - increased. The increase of coarse aggregate quantity acted differently: plastic viscosity and yield stress decreased. Finally, the increase of fine particles quantity decreased the plastic viscosity as well as yield stress of concrete mixture.

  19. The use of waste materials in asphalt concrete mixtures.

    PubMed

    Tuncan, Mustafa; Tuncan, Ahmet; Cetin, Altan

    2003-04-01

    The purpose of this study was to investigate (a) the effects of rubber and plastic concentrations and rubber particle sizes on properties of asphalt cement, (b) on properties of asphalt concrete specimens and (c) the effects of fly ash, marble powder, rubber powder and petroleum contaminated soil as filler materials instead of stone powder in the asphalt concrete specimens. One type of limestone aggregate and one penetration-graded asphalt cement (75-100) were used. Three concentrations of rubber and plastic (i.e. 5%, 10% and 20% of the total weight of asphalt cement), three rubber particle sizes (i.e. No. 4 [4.75mm] - 20 [0.85 mm], No. 20 [0.85mm] - 200 [0.075mm] and No. 4 [4.75mm] - 200 [0.075mm]) and one plastic particle size (i.e. No. 4 [4.75mm] - 10 [2.00mm]) were also used. It was found that while the addition of plastic significantly increased the strength of specimens, the addition of rubber decreased it. No. 4 [4.75mm] - 200 [0.075mm] rubber particles showed the best results with respect to the indirect tensile test. The Marshall stability and indirect tensile strength properties of plastic modified specimens increased. Marble powder and fly ash could be used as filler materials instead of stone powder in the asphalt concrete pavement specimens.

  20. Peptide identification by database search of mixture tandem mass spectra.

    PubMed

    Wang, Jian; Bourne, Philip E; Bandeira, Nuno

    2011-12-01

    In high-throughput proteomics the development of computational methods and novel experimental strategies often rely on each other. In certain areas, mass spectrometry methods for data acquisition are ahead of computational methods to interpret the resulting tandem mass spectra. Particularly, although there are numerous situations in which a mixture tandem mass spectrum can contain fragment ions from two or more peptides, nearly all database search tools still make the assumption that each tandem mass spectrum comes from one peptide. Common examples include mixture spectra from co-eluting peptides in complex samples, spectra generated from data-independent acquisition methods, and spectra from peptides with complex post-translational modifications. We propose a new database search tool (MixDB) that is able to identify mixture tandem mass spectra from more than one peptide. We show that peptides can be reliably identified with up to 95% accuracy from mixture spectra while considering only a 0.01% of all possible peptide pairs (four orders of magnitude speedup). Comparison with current database search methods indicates that our approach has better or comparable sensitivity and precision at identifying single-peptide spectra while simultaneously being able to identify 38% more peptides from mixture spectra at significantly higher precision.

  1. Estimating the mass of mutagens in indeterminate mixtures

    SciTech Connect

    Schaeffer, D.J.; Kerster, H.W.

    1985-10-01

    A method is shown for estimating the quantity (mass) of genotoxic compounds in complex mixtures without prior identification of components. This method uses fractiles of the probability distribution of responses from the assay of interest and dose-response of the mixture. The method depends upon the assumption of additivity, on average, in the interaction of mutagens and on lognormality of the distribution of mutagen molecular weights. Mass estimates are necessary for hazard characterization, risk estimation, and risk assessment. The method is illustrated using Ames assay results from a coke plant wastewater.

  2. Thermodynamic evaluation of mass diffusion in ionic mixtures

    SciTech Connect

    Kagan, Grigory; Tang, Xian-Zhu

    2014-02-15

    The thermodynamic technique of Landau and Lifshitz originally developed for inter-species diffusion in a binary neutral gas mixture is extended to a quasi-neutral plasma with two ion species. It is shown that, while baro- and electro-diffusion coefficients depend on the choice of the thermodynamic system, prediction for the total diffusive mass flux is invariant.

  3. Performance of intact and partially degraded concrete barriers in limiting mass transport

    SciTech Connect

    Walton, J.C. )

    1992-06-01

    Mass transport through concrete barriers and release rate from concrete vaults are quantitatively evaluated. The thorny issue of appropriate diffusion coefficients for use in performance assessment calculations is covered, with no ultimate solution found. Release from monolithic concrete vaults composed of concrete waste forms is estimated with a semi-analytical solution. A parametric study illustrates the importance of different parameters on release. A second situation of importance is the role of a concrete shell or vault placed around typical waste forms in limiting mass transport. In both situations, the primary factor controlling concrete performance is cracks. The implications of leaching behavior on likely groundwater concentrations is examined. Frequently, lower groundwater concentrations can be expected in the absence of engineered covers that reduce infiltration.

  4. Progress Towards a Quantum Degenerate Mixture with Extreme Mass Imbalance

    NASA Astrophysics Data System (ADS)

    Desalvo, B. J.; Johansen, Jacob; Chin, Cheng

    2016-05-01

    We report experimental progress towards a quantum degenerate Bose-Fermi mixture of 133 Cs and 6 Li. Beyond providing the largest mass imbalance of any bi-alkali mixture, this system exhibits multiple interspecies Feshbach resonances allowing wide tuning of the interaction strength and Efimov resonances potentially inducing three-body interactions. The use of a dual-color optical dipole trap in our experiment overcomes the large differential gravitational sag due to the mass imbalance and facilitates mixing the species nano-Kelvin temperatures allowing precision studies of interspecies interactions. Turning from few-body physics to many-body, we will present our efforts to reach simultaneous quantum degeneracy as well as discuss prospects of high resolution imaging of both species.

  5. Higher-order mass defect analysis for mass spectra of complex organic mixtures.

    PubMed

    Roach, Patrick J; Laskin, Julia; Laskin, Alexander

    2011-06-15

    Higher-order mass defect analysis is introduced as a unique formula assignment and visualization method for the analysis of complex mass spectra. This approach is an extension of the concepts of Kendrick mass transformation widely used for identification of homologous compounds differing only by a number of base units (e.g., CH(2), H(2), O, CH(2)O, etc.) in complex mixtures. We present an iterative renormalization routine for defining higher-order homologous series and multidimensional clustering of mass spectral features. This approach greatly simplifies visualization of complex mass spectra and increases the number of chemical formulas that can be confidently assigned for given mass accuracy. The potential for using higher-order mass defects for data reduction and visualization is shown. Higher-order mass defect analysis is described and demonstrated through third-order analysis of a deisotoped high-resolution mass spectrum of crude oil containing nearly 13,000 peaks. PMID:21526851

  6. Internal structure of shock waves in disparate mass mixtures

    NASA Technical Reports Server (NTRS)

    Chung, Chan-Hong; De Witt, Kenneth J.; Jeng, Duen-Ren; Penko, Paul F.

    1992-01-01

    The detailed flow structure of a normal shock wave for a gas mixture is investigated using the direct-simulation Monte Carlo method. A variable diameter hard-sphere (VDHS) model is employed to investigate the effect of different viscosity temperature exponents (VTE) for each species in a gas mixture. Special attention is paid to the irregular behavior in the density profiles which was previously observed in a helium-xenon experiment. It is shown that the VTE can have substantial effects in the prediction of the structure of shock waves. The variable hard-sphere model of Bird shows good agreement, but with some limitations, with the experimental data if a common VTE is chosen properly for each case. The VDHS model shows better agreement with the experimental data without adjusting the VTE. The irregular behavior of the light-gas component in shock waves of disparate mass mixtures is observed not only in the density profile, but also in the parallel temperature profile. The strength of the shock wave, the type of molecular interactions, and the mole fraction of heavy species have substantial effects on the existence and structure of the irregularities.

  7. Internal structure of shock waves in disparate mass mixtures

    SciTech Connect

    Chung, Chan-Hong; De witt, K.J.; Jeng, Duen-Ren; Penko, P.F. Toledo, University, OH )

    1992-01-01

    The detailed flow structure of a normal shock wave for a gas mixture is investigated using the direct-simulation Monte Carlo method. A variable diameter hard-sphere (VDHS) model is employed to investigate the effect of different viscosity temperature exponents (VTE) for each species in a gas mixture. Special attention is paid to the irregular behavior in the density profiles which was previously observed in a helium-xenon experiment. It is shown that the VTE can have substantial effects in the prediction of the structure of shock waves. The variable hard-sphere model of Bird shows good agreement, but with some limitations, with the experimental data if a common VTE is chosen properly for each case. The VDHS model shows better agreement with the experimental data without adjusting the VTE. The irregular behavior of the light-gas component in shock waves of disparate mass mixtures is observed not only in the density profile, but also in the parallel temperature profile. The strength of the shock wave, the type of molecular interactions, and the mole fraction of heavy species have substantial effects on the existence and structure of the irregularities. 14 refs.

  8. Effects of the air–steam mixture on the permeability of damaged concrete

    SciTech Connect

    Medjigbodo, Sonagnon; Darquennes, Aveline; Khelidj, Abdelhafid; Loukili, Ahmed

    2013-12-15

    Massive concrete structures such as the containments of nuclear power plant must maintain their tightness at any circumstances to prevent the escape of radioactive fission products into the environment. In the event of an accident like a Loss of Coolant Accident (LOCA), the concrete wall is submitted to both hydric and mechanical loadings. A new experimental device reproducing these extreme conditions (water vapor transfer, 140 °C and 5 bars) is developed in the GeM Laboratory to determine the effect of the saturation degree, the mechanical loading and the flowing fluid type on the concrete transfer properties. The experimental tests show that the previous parameters significantly affect the concrete permeability and the gas leakage rate. Their evolution as a function of the mechanical loading is characterized by two phases that are directly related to concrete microstructure and crack development.

  9. Bayesian decision and mixture models for AE monitoring of steel-concrete composite shear walls

    NASA Astrophysics Data System (ADS)

    Farhidzadeh, Alireza; Epackachi, Siamak; Salamone, Salvatore; Whittaker, Andrew S.

    2015-11-01

    This paper presents an approach based on an acoustic emission technique for the health monitoring of steel-concrete (SC) composite shear walls. SC composite walls consist of plain (unreinforced) concrete sandwiched between steel faceplates. Although the use of SC system construction has been studied extensively for nearly 20 years, little-to-no attention has been devoted to the development of structural health monitoring techniques for the inspection of damage of the concrete behind the steel plates. In this work an unsupervised pattern recognition algorithm based on probability theory is proposed to assess the soundness of the concrete infill, and eventually provide a diagnosis of the SC wall’s health. The approach is validated through an experimental study on a large-scale SC shear wall subjected to a displacement controlled reversed cyclic loading.

  10. Mass effect on the Soret coefficient in n-alkane mixtures.

    PubMed

    Alonso de Mezquia, David; Bou-Ali, M Mounir; Madariaga, J Antonio; Santamaría, Carlos

    2014-02-28

    We have determined the Soret coefficient of different equimolar and non equimolar n-alkane mixtures from measurements of the molecular diffusion and thermal diffusion coefficients. It is shown that equimolar mixtures behave as isotopic-like mixtures in which only the mass effect contributes to the Soret effect. In non equimolar mixtures, a small linear dependence with the molar fraction is observed. Finally, we have obtained a new correlation, which allows the determination of the Soret coefficient of n-alkane mixtures using the data of viscosity, the thermal expansion coefficient of the pure components, and the density of the equimolar mixture. PMID:24588181

  11. Mass effect on the Soret coefficient in n-alkane mixtures

    SciTech Connect

    Alonso de Mezquia, David; Mounir Bou-Ali, M.; Madariaga, J. Antonio; Santamaría, Carlos

    2014-02-28

    We have determined the Soret coefficient of different equimolar and non equimolar n-alkane mixtures from measurements of the molecular diffusion and thermal diffusion coefficients. It is shown that equimolar mixtures behave as isotopic-like mixtures in which only the mass effect contributes to the Soret effect. In non equimolar mixtures, a small linear dependence with the molar fraction is observed. Finally, we have obtained a new correlation, which allows the determination of the Soret coefficient of n-alkane mixtures using the data of viscosity, the thermal expansion coefficient of the pure components, and the density of the equimolar mixture.

  12. Signal Partitioning Algorithm for Highly Efficient Gaussian Mixture Modeling in Mass Spectrometry

    PubMed Central

    Polanski, Andrzej; Marczyk, Michal; Pietrowska, Monika; Widlak, Piotr; Polanska, Joanna

    2015-01-01

    Mixture - modeling of mass spectra is an approach with many potential applications including peak detection and quantification, smoothing, de-noising, feature extraction and spectral signal compression. However, existing algorithms do not allow for automated analyses of whole spectra. Therefore, despite highlighting potential advantages of mixture modeling of mass spectra of peptide/protein mixtures and some preliminary results presented in several papers, the mixture modeling approach was so far not developed to the stage enabling systematic comparisons with existing software packages for proteomic mass spectra analyses. In this paper we present an efficient algorithm for Gaussian mixture modeling of proteomic mass spectra of different types (e.g., MALDI-ToF profiling, MALDI-IMS). The main idea is automated partitioning of protein mass spectral signal into fragments. The obtained fragments are separately decomposed into Gaussian mixture models. The parameters of the mixture models of fragments are then aggregated to form the mixture model of the whole spectrum. We compare the elaborated algorithm to existing algorithms for peak detection and we demonstrate improvements of peak detection efficiency obtained by using Gaussian mixture modeling. We also show applications of the elaborated algorithm to real proteomic datasets of low and high resolution. PMID:26230717

  13. A fluidic device for measuring constituent masses of a flowing binary gas mixture

    NASA Technical Reports Server (NTRS)

    Prokopius, P. R.

    1973-01-01

    A continuous reading mass flow device was developed to measure the component flow of a binary gas mixture. The basic components of the device are a fluidic humidity sensor and a specially designed flow calorimeter. These components provide readings of gas mixture ratio, mixture heat capacity, heat dissipated by the calorimeter and the gas temperature rise across the calorimeter. These parameter values, applied in the general definitions of specific heat capacity and the heat capacity of a gas mixture, produce calculated component flow rates of the mixture being metered. A test program was conducted to evaluate both the steady state and dynamic performance of the device.

  14. Use of plastic waste (poly-ethylene terephthalate) in asphalt concrete mixture as aggregate replacement.

    PubMed

    Hassani, Abolfazl; Ganjidoust, Hossein; Maghanaki, Amir Abedin

    2005-08-01

    One of the environmental issues in most regions of Iran is the large number of bottles made from poly-ethylene terephthalate (PET) deposited in domestic wastes and landfills. Due to the high volume of these bottles, more than 1 million m3 landfill space is needed for disposal every year. The purpose of this experimental study was to investigate the possibility of using PET waste in asphalt concrete mixes as aggregate replacement (Plastiphalt) to reduce the environmental effects of PET disposal. For this purpose the mechanical properties of plastiphalt mixes were compared with control samples. This study focused on the parameters of Marshall stability, flow, Marshall quotient (stability-to-flow ratio) and density. The waste PET used in this study was in the form of granules of about 3 mm diameter which would replace (by volume) a portion of the mineral coarse aggregates of an equal size (2.36-4.75 mm). In all prepared mixes the determined 6.6% optimum bitumen content was used. In this investigation, five different percentages of coarse aggregate replacement were used. The results showed that the aggregate replacement of 20% by volume with PET granules would result in a reduction of 2.8% in bulk compacted mix density. The value of flow in the plastiphalt mix was lower than that of the control samples. The results also showed that when PET was used as partial aggregate replacement, the corresponding Marshall stability and Marshall quotient were almost the same as for the control samples. According to most of specification requirement, these results introduce an asphalt mix that has properties that makes it suitable for practical use and furthermore, the recycling of PET for asphalt concrete roads helps alleviate an environmental problem and saves energy. PMID:16200982

  15. Mass transport properties of Pu/DT mixtures from orbital free molecular dynamics simulations

    SciTech Connect

    Kress, Joel David; Ticknor, Christopher; Collins, Lee A.

    2015-09-16

    Mass transport properties (shear viscosity and diffusion coefficients) for Pu/DT mixtures were calculated with Orbital Free Molecular Dynamics (OFMD). The results were fitted to simple functions of mass density (for ρ=10.4 to 62.4 g/cm3) and temperature (for T=100 up to 3,000 eV) for Pu/DT mixtures consisting of 100/0, 25/75, 50/50, and 75/25 by number.

  16. Using biological and physico-chemical test methods to assess the role of concrete mixture design in resistance to microbially induced corrosion

    NASA Astrophysics Data System (ADS)

    House, Mitchell Wayne

    to evaluate performance of concrete specimens under conditions designed to accelerate MIC. Concrete specimens representing 12 mixture designs were inoculated with 5 species of Thiobacillus bacteria and placed in a biological growth chamber designed to encourage bacterial growth and sulfuric acid production by optimizing temperature, delivering necessary nutrients, and providing hydrogen sulfide gas. Results indicate that using supplementary cementitious materials, limestone aggregates, and sulfate resistant cement can improve resistance to MIC. It is interesting to note that this study showed that unlike many other durability problems the role of water to cement ratio was unclear. The second method presented is a sulfuric acid immersion study designed to evaluate the resistance of 12 concrete mixture designs to 5 concentrations of sulfuric acid. Experimental protocols (like those in ASTM) previously considered trivial were found to have a dramatic effect on experimental results. It was found that using supplementary cementitious materials, limestone coarse aggregate, and sulfate resistant cement can increase concrete resistance to moderate sulfuric acid concentrations. The primary damage mechanism was observed to change depending on sulfuric acid concentration. Rapid deterioration of specimens exposed to aggressive sulfuric acid solutions indicates that degradation of concrete under the most severe MIC conditions (i.e., a pH < 1.0) cannot be prevented by strictly manipulating concrete mixture proportions. A holistic approach is needed for these situations that considers environmental conditions as well.

  17. The Value Compressive Strength and Split Tensile Strength on Concrete Mixture With Expanded Polystyrene Coated by Surfactant Span 80 as a Partial Substitution of Fine Aggregate

    NASA Astrophysics Data System (ADS)

    Hidayat, Irpan; Siauwantara, Alice

    2014-03-01

    The value of the density normal concrete which ranges between 2200-2400 kg/m3. Therefore the use of Expanded Polystyrene (EPS) as a subitute to fine aggregate can reduce the density of concrete. The purpose this research is to reduce the density of normal concrete but increase compressive strength of EPS concrete, with use surfactant as coating for the EPS. Variables of substitution percentage of EPS and EPS coated by surfactant are 5%,10%,15%,20%,25%. Method of concrete mix design based on SNI 03-2834-2000 "Tata Cara Pembuatan Rencana Campuran Beton Normal (Provisions for Proportioning Normal Concrete Mixture)". The result of testing, every increase percentage of EPS substitution will decrease the compressive strength around 1,74 MPa and decrease density 34,03 kg/m3. Using Surfactant as coating of EPS , compressive strength increase from the EPS's compressive strength. Average of increasing compressive strength 0,19 MPa and increase the density 20,03 kg/m3,average decrease of the tensile split strength EPS coated surfaktan is 0,84 MPa.

  18. Direct analysis of ethylenediaminetetraacetic acid (EDTA) on concrete by reactive-desorption electrospray ionization mass spectrometry.

    PubMed

    Lebeau, D; Reiller, P E; Lamouroux, C

    2015-01-01

    Analysis of organic ligands such as ethylenediaminetetraacetic acid (EDTA) is today an important challenge due to their ability to increase the mobility of radionuclides and metals. Reactive desorption electrospray ionization mass spectrometry (reactive-DESI-MS) was used for direct analysis of EDTA on concrete samples. EDTA forms complexes and those with Fe(III) ions are among the most thermodynamically favored. This complexing capacity was used to improve the specific detection of EDTA directly on a concrete matrix by doping the solvent spray of DESI with a solution of FeCl3 to selectively create the complex between EDTA and Fe(III). Thus, EDTA sensitivity was largely improved by two orders of magnitude with reactive-DESI-MS experiments thanks to the specific detection of EDTA as a [EDTA-4H+Fe(III)](-) complex. The proof of principle that reactive DESI can be applied to concrete samples to detect EDTA has been demonstrated. Its capacity for semi-quantitative determination and localization of EDTA under ambient conditions and with very little sample preparation, minimizing sample manipulations and solvent volumes, two important conditions for the development of new methodologies in the field of analytical chemistry, has been shown.

  19. Study of mass attenuation coefficients and effective atomic numbers of bismuth-ground granulated blast furnace slag concretes

    NASA Astrophysics Data System (ADS)

    Kumar, Sandeep; Singh, Sukhpal

    2016-05-01

    Five samples of Bismuth-Ground granulated blast furnace slag (Bi-GGBFS) concretes were prepared using composition (0.6 cement + x Bi2O3 + (0.4-x) GGBFS, x = 0.05, 0.10, 0.15, 0.20 and 0.25) by keeping constant water (W) cement (C) ratio. Mass attenuation coefficients (μm) of these prepared samples were calculated using a computer program winXCOM at different gamma ray energies, whereas effective atomic numbers (Zeff) is calculated using mathematical formulas. The radiation shielding properties of Bi-GGBFS concrete has been compared with standard radiation shielding concretes.

  20. Evaluation of ASTM test method D 4867, effect of moisture on asphalt concrete paving mixtures. Final report, May 1995--May 1997

    SciTech Connect

    Stuart, K.D.

    1998-09-01

    The moisture sensitivities of 21 dense-graded asphalt pavements were predicted in 1987 using American Society for Testing and Materials (ASTM) Test Method D 4867, Effect of Moisture on Asphalt Concrete Paving Mixtures. Tests were performed on cores taken from the pavements. The air-void levels of the cores varied from pavement to pavement. In 1995 and 1996, cores were again taken from the pavements to ascertain whether the test method correctly predicted performance. Pavement distress surveys were also performed.

  1. Numerical Analysis of Simultaneous Heat and Mass Transfer in Cork Lightweight Concretes Used in Building Envelopes

    NASA Astrophysics Data System (ADS)

    Sotehi, Nassima; Chaker, Abla

    A numerical study was carried out in order to investigate the behaviour of building envelopes made of lightweight concretes. In this work, we are particularly interested to the building envelopes which are consist of cement paste with incorporation of cork aggregates in order to obtain small thermal conductivity and low-density materials. The mathematical formulation of coupled heat and mass transfer in wet porous materials has been made using Luikov's model, the system describing temperature and moisture transfer processes within building walls is solved numerically with the finite elements method. The obtained results illustrate the temporal evolutions of the temperature and the moisture content, and the distributions of the temperature and moisture content inside the wall for several periods of time. They allow us to specify the effect of the nature and dosage of fibre on the heat and mass transfer.

  2. Determination of mass attenuation coefficients, effective atomic numbers and effective electron numbers for heavy-weight and normal-weight concretes.

    PubMed

    Un, Adem; Demir, Faruk

    2013-10-01

    Total mass attenuation coefficients, effective atomic numbers and effective electron numbers values for different 16 heavy-weight and normal-weight concretes are calculated in the energy range from 1 keV to 100 GeV. The values of mass attenuation coefficients used in calculations are taken from the WinXCom computer program. The obtained results for heavy-weight concretes are compared with the results for normal-weight concretes. The results of heavy-weight concretes fairly differ from results for normal-weight concretes.

  3. Estimation of explosive charge mass used for explosions on concrete surface for the forensic purpose.

    PubMed

    Bjelovuk, Ivana D; Jaramaz, Slobodan; Mickovic, Dejan

    2012-03-01

    The method of choice used by most terrorists for achieving political goals remains the utilization of explosive devices and there is always visible evidence at a crime scene after the deployment of such devices. Given favorable circumstances, forensic analysis can determine the cause of the explosion - the type of the explosive device, the means of detonation, the type and mass of the explosive charge that has been used and perhaps provide information to lead to the identity of the individual who may have constructed or deployed the explosive device, etc. Evidence of an explosion may take the form of a crater or other damage which may provide some information facilitating and estimating the mass of explosive material used. This paper reports the findings obtained by performing experimental explosions of known charges on a concrete surface, in order to establish the correlation between the charge weight and the effects of the explosion. Known masses of explosives were fired and the dimensions of craters made by explosions were measured. Five empirical equations for estimation of the explosive charge mass from crater dimensions were used.

  4. ION COMPOSITION ELUCIDATION (ICE): A HIGH RESOLUTION MASS SPECTROMETRIC TECHNIQUE FOR IDENTIFYING COMPOUNDS IN COMPLEX MIXTURES

    EPA Science Inventory

    When tentatively identifying compounds in complex mixtures using mass spectral libraries, multiple matches or no plausible matches due to a high level of chemical noise or interferences can occur. Worse yet, most analytes are not in the libraries. In each case, Ion Composition El...

  5. Viscous slip coefficients for binary gas mixtures measured from mass flow rates through a single microtube

    NASA Astrophysics Data System (ADS)

    Yamaguchi, H.; Takamori, K.; Perrier, P.; Graur, I.; Matsuda, Y.; Niimi, T.

    2016-09-01

    The viscous slip coefficient for helium-argon binary gas mixture is extracted from the experimental values of the mass flow rate through a microtube. The mass flow rate is measured by the constant-volume method. The viscous slip coefficient was obtained by identifying the measured mass flow rate through a microtube with the corresponding analytical expression, which is a function of the Knudsen number. The measurements were carried out in the slip flow regime where the first-order slip boundary condition can be applied. The measured viscous slip coefficients of binary gas mixtures exhibit a concave function of the molar ratio of the mixture, showing a similar profile with numerical results. However, from the detailed comparison between the measured and numerical values with the complete and incomplete accommodation at a surface, it is inappropriate to estimate the viscous slip coefficient for the mixture numerically by employing separately measured tangential momentum accommodation coefficient for each component. The time variation of the molar ratio in the downstream chamber was measured by sampling the gas from the chamber using the quadrupole mass spectrometer. In our measurements, it is indicated that the volume flow rate of argon is larger than that of helium because of the difference in the tangential momentum accommodation coefficient.

  6. Effect of coal combustion fly ash use in concrete on the mass transport release of constituents of potential concern.

    PubMed

    Garrabrants, Andrew C; Kosson, David S; DeLapp, Rossane; van der Sloot, Hans A

    2014-05-01

    Concerns about the environmental safety of coal combustion fly ash use as a supplemental cementitious material have necessitated comprehensive evaluation of the potential for leaching concrete materials containing fly ash used as a cement replacement. Using concrete formulations representative of US residential and commercial applications, test monoliths were made without fly ash replacement (i.e., controls) and with 20% or 45% of the portland cement fraction replaced by fly ash from four coal combustion sources. In addition, microconcrete materials were created with 45% fly ash replacement based on the commercial concrete formulation but with no coarse aggregate and an increased fine aggregate fraction to maintain aggregate-paste interfacial area. All materials were cured for 3 months prior to mass transport-based leach testing of constituents of potential concern (i.e., Sb, As, B, Ba, Cd, Cr, Mo, Pb, Se, Tl and V) according to EPA Method 1315. The cumulative release results were consistent with previously tested samples of concretes and mortars from international sources. Of the 11 constituents tested, only Sb, Ba, B, Cr and V were measured in quantifiable amounts. Microconcretes without coarse aggregate were determined to be conservative surrogates for concrete in leaching assessment since cumulative release from microconcretes were only slightly greater than the associated concrete materials. Relative to control materials without fly ash, concretes and microconcretes with fly ash replacement of cement had increased 28-d and 63-d cumulative release for a limited number 10 comparison cases: 2 cases for Sb, 7 cases for Ba and 1 case for Cr. The overall results suggest minimal leaching impact from fly ash use as a replacement for up to 45% of the cement fraction in typical US concrete formulations; however, scenario-specific assessment based on this leaching evaluation should be used to determine if potential environmental impacts exist.

  7. Thermal conductivity of highly asymmetric binary mixtures: how important are heat/mass coupling effects?

    PubMed

    Armstrong, Jeff; Bresme, Fernando

    2014-06-28

    The coupling of mass and heat fluxes is responsible for the Soret effect in fluid mixtures containing particles of dissimilar mass and/or size. We investigate using equilibrium and non-equilibrium molecular dynamics simulations the relevance of these coupling effects in determining the thermal transport in fluids consisting of binary mixtures where the individual components feature significant mass, 1 : 8, or size, 1 : 3, asymmetries. We quantify the thermal transport by using both boundary driven molecular dynamics simulations (NEMD) and the equilibrium Green-Kubo (GK) approach and investigate the impact of different heat flux definitions, relevant in kinetic theory and experiments, in the quantification of the thermal conductivity. We find that the thermal conductivities obtained from the different definitions agree within numerical accuracy, suggesting that the Soret coefficient does not lead to significant changes in the thermal conduction, even for the large asymmetries considered here, which lead to significant Soret coefficients (∼10(-2) K(-1)). The asymmetry in size and mass introduces large differences in the specific enthalpy of the individual components that must be carefully considered to compute accurate thermal conductivities using the GK approach. Neglecting the enthalpic contributions, results in large overestimations of the thermal conductivity, typically between 20% and 50%. Further, we quantify the time dependent behavior of the internal energy and mass flux correlation functions and propose a microscopic mechanism for the heat transport in these asymmetric mixtures.

  8. Automated reduction and interpretation of multidimensional mass spectra for analysis of complex peptide mixtures

    NASA Astrophysics Data System (ADS)

    Gambin, Anna; Dutkowski, Janusz; Karczmarski, Jakub; Kluge, Boguslaw; Kowalczyk, Krzysztof; Ostrowski, Jerzy; Poznanski, Jaroslaw; Tiuryn, Jerzy; Bakun, Magda; Dadlez, Michal

    2007-01-01

    Here we develop a fully automated procedure for the analysis of liquid chromatography-mass spectrometry (LC-MS) datasets collected during the analysis of complex peptide mixtures. We present the underlying algorithm and outcomes of several experiments justifying its applicability. The novelty of our approach is to exploit the multidimensional character of the datasets. It is common knowledge that highly complex peptide mixtures can be analyzed by liquid chromatography coupled with mass spectrometry, but we are not aware of any existing automated MS spectra interpretation procedure designed to take into account the multidimensional character of the data. Our work fills this gap by providing an effective algorithm for this task, allowing for automated conversion of raw data to the list of masses of peptides.

  9. Tetramethylammonium hydroxide as a reagent for complex mixture analysis by negative ion electrospray ionization mass spectrometry.

    PubMed

    Lobodin, Vladislav V; Juyal, Priyanka; McKenna, Amy M; Rodgers, Ryan P; Marshall, Alan G

    2013-08-20

    Ultrahigh-resolution Fourier transform ion cyclotron resonance mass spectrometry (FTICR MS) enables the direct characterization of complex mixtures without prior fractionation. High mass resolution can distinguish peaks separated by as little as 1.1 mDa), and high mass accuracy enables assignment of elemental compositions in mixtures that contain tens of thousands of individual components (crude oil). Negative electrospray ionization (ESI) is particularly useful for the speciation of the most acidic petroleum components that are implicated in oil production and processing problems. Here, we replace conventional ammonium hydroxide by tetramethylammonium hydroxide (TMAH, a much stronger base, with higher solubility in toluene) to more uniformly deprotonate acidic components of complex mixtures by negative ESI FTICR MS. The detailed compositional analysis of four crude oils (light to heavy, from different geographical locations) reveals that TMAH reagent accesses 1.5-6 times as many elemental compositions, spanning a much wider range of chemical classes than does NH4OH. For example, TMAH reagent produces abundant negative electrosprayed ions from less acidic and neutral species that are in low abundance or absent with NH4OH reagent. More importantly, the increased compositional coverage of TMAH-modified solvent systems maintains, or even surpasses, the compositional information for the most acidic species. The method is not limited to petroleum-derived materials and could be applied to the analysis of dissolved organic matter, coal, lipids, and other naturally occurring compositionally complex organic mixtures. PMID:23919350

  10. High-strength lightweight concrete mixtures based on hollow microspheres: technological features and industrial experience of preparation

    NASA Astrophysics Data System (ADS)

    Inozemtcev, A. S.

    2015-01-01

    The research results concerning dependencies between technological parameters and physical properties of structural lightweight concrete are presented in the article. High-strength lightweight concrete has unique performance characteristics: low average density (less than 1500 kg/m3) and high compressive strength (more than 70 MPa). Hollow alumina-silicate microspheres with nanoscale modifier are used for obtaining these properties. It is shown in the article that the preparation of high-strength lightweight concrete in industrial conditions must be implemented using a turbine mixer having six paddles and engine power more than 39.2 kW. Oscillation frequency of more than 3000 rpm, vibro-compacting time less than 15 seconds, heat-humid treatment temperature approximately 60-65 °C and heat-humid treatment time 6-7 hours are optimal for production. The results of industrial mixing-test are presented.

  11. Quantitative measurements of small molecule mixtures using laser electrospray mass spectrometry.

    PubMed

    Flanigan, Paul M; Perez, Johnny J; Karki, Santosh; Levis, Robert J

    2013-04-01

    Quantitative measurements of atenolol, tioconazole, tetraethylammonium bromide, and tetrabutylammonium iodide using laser electrospray mass spectrometry (LEMS) reveal monotonic signal response as a function of concentration for single analytes, two- and four-component equimolar mixtures, and two-component variable molarity mixtures. LEMS analyses of single analytes as a function of concentration were linear over ~2.5 orders of magnitude for all four analytes and displayed no sign of saturation. Corresponding electrospray ionization (ESI) measurements displayed a nonmonotonic increase as saturation occurred at higher concentrations. In contrast to the LEMS experiments, the intensity ratios from control experiments using conventional ESI-MS deviated from expected values for the equimolar mixture measurements due to ion suppression of less surface active analytes, particularly in the analysis of the four-component mixture. In the analyses of two-component nonequimolar mixtures, both techniques were able to determine the concentration ratios after adjustment with response factors although conventional ESI-MS was subject to a greater degree of saturation and ion suppression at higher analyte concentrations.

  12. Observation of Coupled Vortex Lattices in a Mass-Imbalance Bose and Fermi Superfluid Mixture

    NASA Astrophysics Data System (ADS)

    Yao, Xing-Can; Chen, Hao-Ze; Wu, Yu-Ping; Liu, Xiang-Pei; Wang, Xiao-Qiong; Jiang, Xiao; Deng, Youjin; Chen, Yu-Ao; Pan, Jian-Wei

    2016-09-01

    Quantized vortices play an essential role in diverse superfluid phenomena. In a Bose-Fermi superfluid mixture, especially of two mass-imbalance species, such macroscopic quantum phenomena are particularly rich due to the interplay between the Bose and Fermi superfluidity. However, generating a Bose-Fermi two-species superfluid, producing coupled vortex lattices within, and further probing interspecies interaction effects remain challenging. Here, we experimentally realize a two-species superfluid with dilute gases of lithium-6 and potassium-41, having a mass ratio of about seven. By rotating the superfluid mixture, we simultaneously produce coupled vortex lattices of the two species and thus present a definitive visual evidence for the double superfluidity. Moreover, we report several unconventional behaviors, due to the Bose-Fermi interaction, on the formation and decay of two-species vortices.

  13. Cryotrapping assisted mass spectrometry for the analysis of complex gas mixtures

    SciTech Connect

    Ferreira, Jose A.; Tabares, Francisco L.

    2007-03-15

    A simple method is described for the unambiguous identification of the individual components in a gas mixture showing strong overlapping of their mass spectrometric cracking patterns. The method, herein referred to as cryotrapping assisted mass spectrometry, takes advantage of the different vapor pressure values of the individual components at low temperature (78 K for liquid nitrogen traps), and thus of the different depletion efficiencies and outgassing patterns during the fast cooling and slow warming up of the trap, respectively. Examples of the use of this technique for gas mixtures with application to plasma enhanced chemical vapor deposition of carbon and carbon-nitrogen hard films are shown. Detection of traces of specific C{sub 3} hydrocarbons (<50 ppm of initial methane) in methane/hydrogen plasmas and the possible trapping of thermally unstable C-N compounds in N{sub 2} containing deposition plasmas are addressed as representative examples of specific applications of the technique.

  14. Modeling of concrete cracking due to corrosion of embedded reinforcement

    NASA Astrophysics Data System (ADS)

    Aligizaki, Kalliopi K.

    Corrosion of steel in concrete continues freely after concrete cracks, because concrete does not provide even physical protection to steel any more. In this Thesis, the effects of concrete quality and design parameters on concrete cracking due to corrosion of embedded reinforcement are examined. The parameters tested are concrete strength, thickness of concrete cover, diameter of steel bar, crack width at the concrete surface, the presence of polypropylene fibers, and corrosion occurring at a limited length. Four air-entrained concrete mixtures were proportioned having different water-cement ratios (0.40, 0.45, 0.50 and 0.55). The control mixture was selected according to the classifications used by the Eurocode and to represent concrete used in a marine environment. An additional mixture was proportioned containing polypropylene fibers. A total of 148 reinforced concrete specimens (250 x 140 x 140 mm) containing one ribbed steel bar were prepared in the laboratory. Corrosion of the reinforcing steel bars was accelerated by two ways: (a) by adding NaCl in the initial concrete mixtures in an amount of 3.7% by mass of cement, and (b) by anodically charging the steel bar with a current density of 500 mA/m2. Different electrochemical tests were carried out before anodically charging the steel bars and after concrete cracked due to corrosion of embedded reinforcement, in order to determine various electrochemical parameters. After the concrete specimens cracked, the average crack width at the concrete surface and the iron mass loss were determined. A theoretical model is proposed and is used as the basis for developing the final analytical equation. A polynomial regression analysis was carried out in order to relate the parameters tested in this study to the amount of oxides needed to cause cracking of the concrete cover. For the parameters examined and the assumptions made, the analysis indicates that the model proposed explains 30% of the variation of the iron mass

  15. Developments in mass spectrometry for the analysis of complex protein mixtures

    SciTech Connect

    Khalsa-Moyers, Gurusahai K; McDonald, W Hayes

    2006-01-01

    State-of-the-art proteomics workflows involve multiple interdependent steps: sample preparation, protein peptide separation, mass spectrometry and data analysis.While improvements in any of these steps can increase the depth and breadth of analysis, advances in mass spectrometry have catalysed many of the most important developments. We discuss common classes of mass analysers and how these analysers are put together to produce some of the most popular mass spectrometry platforms.The capabilities of these platforms determine how they can be used in a variety of common proteomic strategies and, in turn, what types of biological questions can be addressed. Moving forward, powerful new hybridmass spectrometers and application of emerging types of tandemmass spectrometry promise that our ability to analyse complex mixtures of proteins will continue to advance.

  16. Coupling Charge Reduction Mass Spectrometry to Liquid Chromatography for Complex Mixture Analysis.

    PubMed

    Stutzman, John R; Crowe, Matthew C; Alexander, James N; Bell, Bruce M; Dunkle, Melissa N

    2016-04-01

    Electrospray ionization (ESI) of solution mixtures often generates complex mass spectra, even following liquid chromatography (LC), due to analyte multiple charging. Multiple charge state distributions can lead to isobaric interferences, mass spectral congestion, and ambiguous ion identification. As a consequence, data interpretation increases in complexity. Several charge reduction mass spectrometry (MS) approaches have been previously developed to reduce the average charge state of gaseous ions; however, all of these techniques have been restricted to direct infusion MS. In this study, synthetic polyols and surfactants separated by liquid chromatography and ionized by positive mode ESI have been subjected to polonium-210 α-particle radiation to reduce the average charge state to singly charged cations prior to mass analysis. LC/MS analysis of 5000 molecular weight poly(ethylene glycol) (PEG5000) generated an average charge state of 5.88+; whereupon, liquid chromatography/electrospray ionization/charge reduction/mass spectrometry (LC/CR/MS) analysis of PEG 5000 generated an average charge state of 1.00+. The PEG5000 results demonstrated a decrease in spectral complexity and enabled facile interpretation. Other complex solution mixtures representing specific MS challenges (i.e., competitive ionization and isobaric ion overlap) were explored and analyzed with LC/CR/MS to demonstrate the benefits of coupling LC to CR/MS. For example, polyol information related to initiator, identity/relative amount of monomer, and estimated molecular weight was characterized in random and triblock ethylene oxide/propylene oxide polyols using LC/CR/MS. LC/CR/MS is a new analytical technique for the analysis of complex mixtures. PMID:26971559

  17. Minimum Error Fickian Diffusion Coefficients for Mass Diffusion in Multicomponent Gas Mixtures

    NASA Astrophysics Data System (ADS)

    Subramaniam, S.

    1999-04-01

    Mass diffusion in multicomponent gas mixtures is governed by a coupled system of linear equations for the diffusive mass fluxes in terms of thermodynamic driving forces, known as the generalized Stefan-Maxwell equation. In computations of mass diffusion in multicomponent gas mixtures, this coupling between the different components results in considerable computational overhead. Consequently, simplified diffusion models for the diffusive mass fluxes as explicit functions of the driving forces are an attractive alternative. These models can be interpreted as an approximate solution to the Stefan-Maxwell equation. Simplified diffusion models require the specification of “effective” diffusion coefficients which are usually expressed as functions of the binary diffusion coefficients of each species pair in the mixture. Current models for the effective diffusion coefficients are incapable of providing a priori control over the error incurred in the approximate solution. In this paper a general form for diagonal approximations is derived, which accounts for the requirement imposed by the special structure of the Stefan-Maxwell equation that such approximations be constructed in a reduced-dimensional subspace. In addition, it is shown that current models can be expressed as particular cases of two general forms, but not all these models correspond to the general form for diagonal approximations. A new minimum error diagonal approximation (MEDA) model is proposed, based on the criterion that the diagonal approximation minimize the error in the species velocities. Analytic expressions are derived for the MEDA model's effective diffusion coefficients based on this criterion. These effective diffusion coefficients automatically give the correct solution in two important limiting cases: for that of a binary mixture, and for the case of arbitrary number of components with identical binary diffusivities. Although these minimum error effective diffusion

  18. DetectTLC: Automated Reaction Mixture Screening Utilizing Quantitative Mass Spectrometry Image Features

    NASA Astrophysics Data System (ADS)

    Kaddi, Chanchala D.; Bennett, Rachel V.; Paine, Martin R. L.; Banks, Mitchel D.; Weber, Arthur L.; Fernández, Facundo M.; Wang, May D.

    2016-02-01

    Full characterization of complex reaction mixtures is necessary to understand mechanisms, optimize yields, and elucidate secondary reaction pathways. Molecular-level information for species in such mixtures can be readily obtained by coupling mass spectrometry imaging (MSI) with thin layer chromatography (TLC) separations. User-guided investigation of imaging data for mixture components with known m/z values is generally straightforward; however, spot detection for unknowns is highly tedious, and limits the applicability of MSI in conjunction with TLC. To accelerate imaging data mining, we developed DetectTLC, an approach that automatically identifies m/z values exhibiting TLC spot-like regions in MS molecular images. Furthermore, DetectTLC can also spatially match m/z values for spots acquired during alternating high and low collision-energy scans, pairing product ions with precursors to enhance structural identification. As an example, DetectTLC is applied to the identification and structural confirmation of unknown, yet significant, products of abiotic pyrazinone and aminopyrazine nucleoside analog synthesis.

  19. DetectTLC: Automated Reaction Mixture Screening Utilizing Quantitative Mass Spectrometry Image Feature

    PubMed Central

    Kaddi, Chanchala D.; Bennett, Rachel V.; Paine, Martin R. L.; Banks, Mitchel D.; Weber, Arthur L.; Fernández, Facundo M.; Wang, May D.

    2016-01-01

    Full characterization of complex reaction mixtures is necessary to understand mechanisms, optimize yields, and elucidate secondary reaction pathways. Molecular-level information for species in such mixtures can be readily obtained by coupling mass spectrometry imaging (MSI) with thin layer chromatography (TLC) separations. User-guided investigation of imaging data for mixture components with known m/z values is generally straightforward; however, spot detection for unknowns is highly tedious, and limits the applicability of MSI in conjunction with TLC. To accelerate imaging data mining, we developed DetectTLC, an approach that automatically identifies m/z values exhibiting TLC spot-like regions in MS molecular images. Furthermore, DetectTLC can also spatially match m/z values for spots acquired during alternating high and low collision-energy scans, pairing product ions with precursors to enhance structural identification. As an example, DetectTLC is applied to the identification and structural confirmation of unknown, yet significant, products of abiotic pyrazinone and aminopyrazine nucleoside analog synthesis. PMID:26508443

  20. DetectTLC: Automated Reaction Mixture Screening Utilizing Quantitative Mass Spectrometry Image Features.

    PubMed

    Kaddi, Chanchala D; Bennett, Rachel V; Paine, Martin R L; Banks, Mitchel D; Weber, Arthur L; Fernández, Facundo M; Wang, May D

    2016-02-01

    Full characterization of complex reaction mixtures is necessary to understand mechanisms, optimize yields, and elucidate secondary reaction pathways. Molecular-level information for species in such mixtures can be readily obtained by coupling mass spectrometry imaging (MSI) with thin layer chromatography (TLC) separations. User-guided investigation of imaging data for mixture components with known m/z values is generally straightforward; however, spot detection for unknowns is highly tedious, and limits the applicability of MSI in conjunction with TLC. To accelerate imaging data mining, we developed DetectTLC, an approach that automatically identifies m/z values exhibiting TLC spot-like regions in MS molecular images. Furthermore, DetectTLC can also spatially match m/z values for spots acquired during alternating high and low collision-energy scans, pairing product ions with precursors to enhance structural identification. As an example, DetectTLC is applied to the identification and structural confirmation of unknown, yet significant, products of abiotic pyrazinone and aminopyrazine nucleoside analog synthesis. Graphical Abstract ᅟ.

  1. DetectTLC: Automated Reaction Mixture Screening Utilizing Quantitative Mass Spectrometry Image Features.

    PubMed

    Kaddi, Chanchala D; Bennett, Rachel V; Paine, Martin R L; Banks, Mitchel D; Weber, Arthur L; Fernández, Facundo M; Wang, May D

    2016-02-01

    Full characterization of complex reaction mixtures is necessary to understand mechanisms, optimize yields, and elucidate secondary reaction pathways. Molecular-level information for species in such mixtures can be readily obtained by coupling mass spectrometry imaging (MSI) with thin layer chromatography (TLC) separations. User-guided investigation of imaging data for mixture components with known m/z values is generally straightforward; however, spot detection for unknowns is highly tedious, and limits the applicability of MSI in conjunction with TLC. To accelerate imaging data mining, we developed DetectTLC, an approach that automatically identifies m/z values exhibiting TLC spot-like regions in MS molecular images. Furthermore, DetectTLC can also spatially match m/z values for spots acquired during alternating high and low collision-energy scans, pairing product ions with precursors to enhance structural identification. As an example, DetectTLC is applied to the identification and structural confirmation of unknown, yet significant, products of abiotic pyrazinone and aminopyrazine nucleoside analog synthesis. Graphical Abstract ᅟ. PMID:26508443

  2. Direct measurements of mass-specific optical cross sections of single-component aerosol mixtures.

    PubMed

    Radney, James G; Ma, Xiaofei; Gillis, Keith A; Zachariah, Michael R; Hodges, Joseph T; Zangmeister, Christopher D

    2013-09-01

    The optical properties of atmospheric aerosols vary widely, being dependent upon particle composition, morphology, and mixing state. This diversity and complexity of aerosols motivates measurement techniques that can discriminate and quantify a variety of single- and multicomponent aerosols that are both internally and externally mixed. Here, we present a new combination of techniques to directly measure the mass-specific extinction and absorption cross sections of laboratory-generated aerosols that are relevant to atmospheric studies. Our approach employs a tandem differential mobility analyzer, an aerosol particle mass analyzer, cavity ring-down and photoacoustic spectrometers, and a condensation particle counter. This suite of instruments enables measurement of aerosol particle size, mass, extinction and absorption coefficients, and aerosol number density, respectively. Taken together, these observables yield the mass-specific extinction and absorption cross sections without the need to model particle morphology or account for sample collection artifacts. Here we demonstrate the technique in a set of case studies which involve complete separation of aerosol by charge, separation of an external mixture by mass, and discrimination between particle types by effective density and single-scattering albedo. PMID:23875772

  3. Flow of variably fluidized granular masses across three-dimensional terrain I. Coulomb mixture theory

    USGS Publications Warehouse

    Iverson, R.M.; Denlinger, R.P.

    2001-01-01

    Rock avalanches, debris flows, and related phenomena consist of grain-fluid mixtures that move across three-dimensional terrain. In all these phenomena the same basic forces, govern motion, but differing mixture compositions, initial conditions, and boundary conditions yield varied dynamics and deposits. To predict motion of diverse grain-fluid masses from initiation to deposition, we develop a depth-averaged, threedimensional mathematical model that accounts explicitly for solid- and fluid-phase forces and interactions. Model input consists of initial conditions, path topography, basal and internal friction angles of solid grains, viscosity of pore fluid, mixture density, and a mixture diffusivity that controls pore pressure dissipation. Because these properties are constrained by independent measurements, the model requires little or no calibration and yields readily testable predictions. In the limit of vanishing Coulomb friction due to persistent high fluid pressure the model equations describe motion of viscous floods, and in the limit of vanishing fluid stress they describe one-phase granular avalanches. Analysis of intermediate phenomena such as debris flows and pyroclastic flows requires use of the full mixture equations, which can simulate interaction of high-friction surge fronts with more-fluid debris that follows. Special numerical methods (described in the companion paper) are necessary to solve the full equations, but exact analytical solutions of simplified equations provide critical insight. An analytical solution for translational motion of a Coulomb mixture accelerating from rest and descending a uniform slope demonstrates that steady flow can occur only asymptotically. A solution for the asymptotic limit of steady flow in a rectangular channel explains why shear may be concentrated in narrow marginal bands that border a plug of translating debris. Solutions for static equilibrium of source areas describe conditions of incipient slope instability

  4. Chemical Analysis of Complex Organic Mixtures Using Reactive Nanospray Desorption Electrospray Ionization Mass Spectrometry

    SciTech Connect

    Laskin, Julia; Eckert, Peter A.; Roach, Patrick J.; Heath, Brandi S.; Nizkorodov, Sergey A.; Laskin, Alexander

    2012-08-21

    Reactive nanospray desorption electrospray ionization (nano-DESI) combined with high-resolution mass spectrometry was utilized for the analysis of secondary organic aerosol produced through ozonolysis of limonene (LSOA). Previous studies showed that LSOA constituents are multifunctional compounds containing aldehyde and ketone groups. In this study, we used the selectivity of the Girard T (GT) reagent towards carbonyl compounds to examine the utility of reactive nano-DESI for the analysis of complex organic mixtures. In these experiments, 1-100 {micro}M GT solution was used as a working solvent for reactive nano-DESI analysis. Abundant products of a single addition of GT to LSOA constituents were observed at GT concentrations in excess of 10 {micro}M. We found that LSOA compounds with 18-20 carbon atoms (dimers) and 27-30 carbon atoms (trimers) react with GT through a simple addition reaction resulting in formation of the carbinolamine derivative. In contrast, reactions of GT with monomeric species result in formation of both the carbinolamine and the hydrazone derivatives. In addition, several monomers did not react with GT on the timescale of our experiment. These molecules were characterized by relatively high values of the double bond equivalent (DBE) and low oxygen content. Furthermore, because addition of a charged GT tag to a neutral molecule eliminates the discrimination against the low proton affinity compounds in the ionization process, reactive nano-DESI analysis enables quantification of individual compounds in the complex mixture. For example, we were able to estimate for the first time the amounts of dimers and trimers in the LSOA mixture. Specifically, we found that the most abundant LSOA dimer was detected at ca. 0.5 pg level and the total amount of dimers and trimers in the analyzed sample was just around 11 pg. Our results indicate that reactive nano-DESI is a valuable approach for examining the presence of specific functional groups and

  5. Chemical analysis of complex organic mixtures using reactive nanospray desorption electrospray ionization mass spectrometry.

    PubMed

    Laskin, Julia; Eckert, Peter A; Roach, Patrick J; Heath, Brandi S; Nizkorodov, Sergey A; Laskin, Alexander

    2012-08-21

    Reactive nanospray desorption electrospray ionization (nano-DESI) combined with high-resolution mass spectrometry was utilized for the analysis of secondary organic aerosol produced through ozonolysis of limonene (LSOA). Previous studies have shown that LSOA constituents are multifunctional compounds containing at least one aldehyde or ketone groups. In this study, we used the selectivity of the Girard's reagent T (GT) toward carbonyl compounds to examine the utility of reactive nano-DESI for the analysis of complex organic mixtures. In these experiments, 1-100 μM GT solutions were used as the working solvents for reactive nano-DESI analysis. Abundant products from the single addition of GT to LSOA constituents were observed at GT concentrations in excess of 10 μM. We found that LSOA dimeric and trimeric compounds react with GT through a simple addition reaction resulting in formation of the carbinolamine derivative. In contrast, reactions of GT with monomeric species result in the formation of both the carbinolamine and the hydrazone derivatives. In addition, several monomers did not react with GT on the time scale of our experiment. These molecules were characterized by relatively high values of the double bond equivalent and low oxygen content. Furthermore, because addition of a charged GT tag to a neutral molecule eliminates the discrimination against the low proton affinity compounds in the ionization process, reactive nano-DESI analysis enables quantification of individual compounds in the complex mixture. For example, we were able to estimate for the first time the amounts of dimers and trimers in the LSOA mixture. Specifically, we found that the most abundant LSOA dimer was detected at the ~0.5 pg level and the total amount of dimers and trimers in the analyzed sample was ~11 pg. Our results indicate that reactive nano-DESI is a valuable approach for examining the presence of specific functional groups and for the quantification of compounds possessing

  6. Mixture model-based atmospheric air mass classification: a probabilistic view of thermodynamic profiles

    NASA Astrophysics Data System (ADS)

    Pernin, Jérôme; Vrac, Mathieu; Crevoisier, Cyril; Chédin, Alain

    2016-10-01

    Air mass classification has become an important area in synoptic climatology, simplifying the complexity of the atmosphere by dividing the atmosphere into discrete similar thermodynamic patterns. However, the constant growth of atmospheric databases in both size and complexity implies the need to develop new adaptive classifications. Here, we propose a robust unsupervised and supervised classification methodology of a large thermodynamic dataset, on a global scale and over several years, into discrete air mass groups homogeneous in both temperature and humidity that also provides underlying probability laws. Temperature and humidity at different pressure levels are aggregated into a set of cumulative distribution function (CDF) values instead of classical ones. The method is based on a Gaussian mixture model and uses the expectation-maximization (EM) algorithm to estimate the parameters of the mixture. Spatially gridded thermodynamic profiles come from ECMWF reanalyses spanning the period 2000-2009. Different aspects are investigated, such as the sensitivity of the classification process to both temporal and spatial samplings of the training dataset. Comparisons of the classifications made either by the EM algorithm or by the widely used k-means algorithm show that the former can be viewed as a generalization of the latter. Moreover, the EM algorithm delivers, for each observation, the probabilities of belonging to each class, as well as the associated uncertainty. Finally, a decision tree is proposed as a tool for interpreting the different classes, highlighting the relative importance of temperature and humidity in the classification process.

  7. Development of a rapid test method for asphalt concrete content determination in hot-mix paving mixtures

    NASA Astrophysics Data System (ADS)

    Chavez, J. J. M.

    1984-01-01

    A rapid test method was developed for the determination of asphalt cement content in hot-mix bituminous paving mixtures. It is based on the extraction of asphalt cement from mixtures with trichloroethylene and subsequent measurement of the transmittance of light through the extracted solution. A good correlation was found between the results obtained using the rapid test and those obtained using the standard test (ASTM D-2172, Method E1) for samples tested in the field at asphalt mix plants. The test uses a portable spectrophotometer and a metal can for extraction. The asphalt content can be determined in less than ten minutes. The possibility of using the rapid test on materials containing emulsified asphalt, slag aggregate, unusually high amounts of fine material and recycled material was also studied.

  8. Species Determination and Quantitation in Mixtures Using MRM Mass Spectrometry of Peptides Applied to Meat Authentication.

    PubMed

    Gunning, Yvonne; Watson, Andrew D; Rigby, Neil M; Philo, Mark; Peazer, Joshua K; Kemsley, E Kate

    2016-09-20

    We describe a simple protocol for identifying and quantifying the two components in binary mixtures of species possessing one or more similar proteins. Central to the method is the identification of 'corresponding proteins' in the species of interest, in other words proteins that are nominally the same but possess species-specific sequence differences. When subject to proteolysis, corresponding proteins will give rise to some peptides which are likewise similar but with species-specific variants. These are 'corresponding peptides'. Species-specific peptides can be used as markers for species determination, while pairs of corresponding peptides permit relative quantitation of two species in a mixture. The peptides are detected using multiple reaction monitoring (MRM) mass spectrometry, a highly specific technique that enables peptide-based species determination even in complex systems. In addition, the ratio of MRM peak areas deriving from corresponding peptides supports relative quantitation. Since corresponding proteins and peptides will, in the main, behave similarly in both processing and in experimental extraction and sample preparation, the relative quantitation should remain comparatively robust. In addition, this approach does not need the standards and calibrations required by absolute quantitation methods. The protocol is described in the context of red meats, which have convenient corresponding proteins in the form of their respective myoglobins. This application is relevant to food fraud detection: the method can detect 1% weight for weight of horse meat in beef. The corresponding protein, corresponding peptide (CPCP) relative quantitation using MRM peak area ratios gives good estimates of the weight for weight composition of a horse plus beef mixture.

  9. Species Determination and Quantitation in Mixtures Using MRM Mass Spectrometry of Peptides Applied to Meat Authentication.

    PubMed

    Gunning, Yvonne; Watson, Andrew D; Rigby, Neil M; Philo, Mark; Peazer, Joshua K; Kemsley, E Kate

    2016-01-01

    We describe a simple protocol for identifying and quantifying the two components in binary mixtures of species possessing one or more similar proteins. Central to the method is the identification of 'corresponding proteins' in the species of interest, in other words proteins that are nominally the same but possess species-specific sequence differences. When subject to proteolysis, corresponding proteins will give rise to some peptides which are likewise similar but with species-specific variants. These are 'corresponding peptides'. Species-specific peptides can be used as markers for species determination, while pairs of corresponding peptides permit relative quantitation of two species in a mixture. The peptides are detected using multiple reaction monitoring (MRM) mass spectrometry, a highly specific technique that enables peptide-based species determination even in complex systems. In addition, the ratio of MRM peak areas deriving from corresponding peptides supports relative quantitation. Since corresponding proteins and peptides will, in the main, behave similarly in both processing and in experimental extraction and sample preparation, the relative quantitation should remain comparatively robust. In addition, this approach does not need the standards and calibrations required by absolute quantitation methods. The protocol is described in the context of red meats, which have convenient corresponding proteins in the form of their respective myoglobins. This application is relevant to food fraud detection: the method can detect 1% weight for weight of horse meat in beef. The corresponding protein, corresponding peptide (CPCP) relative quantitation using MRM peak area ratios gives good estimates of the weight for weight composition of a horse plus beef mixture. PMID:27685654

  10. Transmission geometry laser desorption atmospheric pressure photochemical ionization mass spectrometry for analysis of complex organic mixtures.

    PubMed

    Nyadong, Leonard; Mapolelo, Mmilili M; Hendrickson, Christopher L; Rodgers, Ryan P; Marshall, Alan G

    2014-11-18

    We present laser desorption atmospheric pressure photochemical ionization mass spectrometry (LD/APPCI MS) for rapid throughput analysis of complex organic mixtures, without the need for matrix, electric discharge, secondary electrospray, or solvents/vaporizers. Analytes dried on a microscope slide are vaporized in transmission geometry by a laser beam aligned with the atmospheric pressure inlet of the mass spectrometer. The laser beam initiates a cascade of reactions in the region between the glass slide and MS inlet, leading to generation of reagent ions for chemical ionization of vaporized analyte. Positive analyte ions are generated predominantly by proton transfer, charge exchange, and hydride abstraction, whereas negative ions are generated by electron capture or proton transfer reactions, enabling simultaneous analysis of saturated, unsaturated, and heteroatom-containing hydrocarbons. The absence of matrix interference renders LD/APPCI MS particularly useful for analysis of small molecules (<2000 Da) such as those present in petroleum crude oil and petroleum deposits. [M + H](+) and M(+•) dominate the positive-ion mass spectra for olefins and polyaromatic hydrocarbons, whereas saturated hydrocarbons are observed mainly as [M - H](+) and/or M(+•). Heteroatom-containing hydrocarbons are observed predominantly as [M + H](+). [M - H](-) and M(-•) are the dominant negative ions observed for analytes of lower gas-phase basicity or higher electron affinity than O2. The source was coupled with a 9.4 T Fourier transform ion cyclotron resonance mass spectrometer (FTICR MS) to resolve and identify thousands of peaks from Athabasca bitumen heavy vacuum gas oil distillates (400-425 and 500-538 °C), enabling simultaneous characterization of their polar and nonpolar composition. We also applied LD/APPCI FTICR MS for rapid analysis of sodium and calcium naphthenate deposits with little to no sample pretreatment to provide mass spectral fingerprints that enable

  11. Transmission geometry laser desorption atmospheric pressure photochemical ionization mass spectrometry for analysis of complex organic mixtures.

    PubMed

    Nyadong, Leonard; Mapolelo, Mmilili M; Hendrickson, Christopher L; Rodgers, Ryan P; Marshall, Alan G

    2014-11-18

    We present laser desorption atmospheric pressure photochemical ionization mass spectrometry (LD/APPCI MS) for rapid throughput analysis of complex organic mixtures, without the need for matrix, electric discharge, secondary electrospray, or solvents/vaporizers. Analytes dried on a microscope slide are vaporized in transmission geometry by a laser beam aligned with the atmospheric pressure inlet of the mass spectrometer. The laser beam initiates a cascade of reactions in the region between the glass slide and MS inlet, leading to generation of reagent ions for chemical ionization of vaporized analyte. Positive analyte ions are generated predominantly by proton transfer, charge exchange, and hydride abstraction, whereas negative ions are generated by electron capture or proton transfer reactions, enabling simultaneous analysis of saturated, unsaturated, and heteroatom-containing hydrocarbons. The absence of matrix interference renders LD/APPCI MS particularly useful for analysis of small molecules (<2000 Da) such as those present in petroleum crude oil and petroleum deposits. [M + H](+) and M(+•) dominate the positive-ion mass spectra for olefins and polyaromatic hydrocarbons, whereas saturated hydrocarbons are observed mainly as [M - H](+) and/or M(+•). Heteroatom-containing hydrocarbons are observed predominantly as [M + H](+). [M - H](-) and M(-•) are the dominant negative ions observed for analytes of lower gas-phase basicity or higher electron affinity than O2. The source was coupled with a 9.4 T Fourier transform ion cyclotron resonance mass spectrometer (FTICR MS) to resolve and identify thousands of peaks from Athabasca bitumen heavy vacuum gas oil distillates (400-425 and 500-538 °C), enabling simultaneous characterization of their polar and nonpolar composition. We also applied LD/APPCI FTICR MS for rapid analysis of sodium and calcium naphthenate deposits with little to no sample pretreatment to provide mass spectral fingerprints that enable

  12. Sampling and analysis method for measuring airborne coal dust mass in mixtures with limestone (rock) dust.

    PubMed

    Barone, T L; Patts, J R; Janisko, S J; Colinet, J F; Patts, L D; Beck, T W; Mischler, S E

    2016-01-01

    Airborne coal dust mass measurements in underground bituminous coal mines can be challenged by the presence of airborne limestone dust, which is an incombustible dust applied to prevent the propagation of dust explosions. To accurately measure the coal portion of this mixed airborne dust, the National Institute for Occupational Safety and Health (NIOSH) developed a sampling and analysis protocol that used a stainless steel cassette adapted with an isokinetic inlet and the low temperature ashing (LTA) analytical method. The Mine Safety and Health Administration (MSHA) routinely utilizes this LTA method to quantify the incombustible content of bulk dust samples collected from the roof, floor, and ribs of mining entries. The use of the stainless steel cassette with isokinetic inlet allowed NIOSH to adopt the LTA method for the analysis of airborne dust samples. Mixtures of known coal and limestone dust masses were prepared in the laboratory, loaded into the stainless steel cassettes, and analyzed to assess the accuracy of this method. Coal dust mass measurements differed from predicted values by an average of 0.5%, 0.2%, and 0.1% for samples containing 20%, 91%, and 95% limestone dust, respectively. The ability of this method to accurately quantify the laboratory samples confirmed the validity of this method and allowed NIOSH to successfully measure the coal fraction of airborne dust samples collected in an underground coal mine.

  13. Doubled heterogeneous crystal nucleation in sediments of hard sphere binary-mass mixtures.

    PubMed

    Löwen, Hartmut; Allahyarov, Elshad

    2011-10-01

    Crystallization during the sedimentation process of a binary colloidal hard spheres mixture is explored by Brownian dynamics computer simulations. The two species are different in buoyant mass but have the same interaction diameter. Starting from a completely mixed system in a finite container, gravity is suddenly turned on, and the crystallization process in the sample is monitored. If the Peclet numbers of the two species are both not too large, crystalline layers are formed at the bottom of the cell. The composition of lighter particles in the sedimented crystal is non-monotonic in the altitude: it is first increasing, then decreasing, and then increasing again. If one Peclet number is large and the other is small, we observe the occurrence of a doubled heterogeneous crystal nucleation process. First, crystalline layers are formed at the bottom container wall which are separated from an amorphous sediment. At the amorphous-fluid interface, a secondary crystal nucleation of layers is identified. This doubled heterogeneous nucleation can be verified in real-space experiments on colloidal mixtures.

  14. Chemical discrimination in turbulent gas mixtures with MOX sensors validated by gas chromatography-mass spectrometry.

    PubMed

    Fonollosa, Jordi; Rodríguez-Luján, Irene; Trincavelli, Marco; Vergara, Alexander; Huerta, Ramón

    2014-10-16

    Chemical detection systems based on chemo-resistive sensors usually include a gas chamber to control the sample air flow and to minimize turbulence. However, such a kind of experimental setup does not reproduce the gas concentration fluctuations observed in natural environments and destroys the spatio-temporal information contained in gas plumes. Aiming at reproducing more realistic environments, we utilize a wind tunnel with two independent gas sources that get naturally mixed along a turbulent flow. For the first time, chemo-resistive gas sensors are exposed to dynamic gas mixtures generated with several concentration levels at the sources. Moreover, the ground truth of gas concentrations at the sensor location was estimated by means of gas chromatography-mass spectrometry. We used a support vector machine as a tool to show that chemo-resistive transduction can be utilized to reliably identify chemical components in dynamic turbulent mixtures, as long as sufficient gas concentration coverage is used. We show that in open sampling systems, training the classifiers only on high concentrations of gases produces less effective classification and that it is important to calibrate the classification method with data at low gas concentrations to achieve optimal performance.

  15. Chemical Discrimination in Turbulent Gas Mixtures with MOX Sensors Validated by Gas Chromatography-Mass Spectrometry

    PubMed Central

    Fonollosa, Jordi; Rodríguez-Luján, Irene; Trincavelli, Marco; Vergara, Alexander; Huerta, Ramón

    2014-01-01

    Chemical detection systems based on chemo-resistive sensors usually include a gas chamber to control the sample air flow and to minimize turbulence. However, such a kind of experimental setup does not reproduce the gas concentration fluctuations observed in natural environments and destroys the spatio-temporal information contained in gas plumes. Aiming at reproducing more realistic environments, we utilize a wind tunnel with two independent gas sources that get naturally mixed along a turbulent flow. For the first time, chemo-resistive gas sensors are exposed to dynamic gas mixtures generated with several concentration levels at the sources. Moreover, the ground truth of gas concentrations at the sensor location was estimated by means of gas chromatography-mass spectrometry. We used a support vector machine as a tool to show that chemo-resistive transduction can be utilized to reliably identify chemical components in dynamic turbulent mixtures, as long as sufficient gas concentration coverage is used. We show that in open sampling systems, training the classifiers only on high concentrations of gases produces less effective classification and that it is important to calibrate the classification method with data at low gas concentrations to achieve optimal performance. PMID:25325339

  16. Reversible jump MCMC approach for peak identification for stroke SELDI mass spectrometry using mixture model.

    PubMed

    Wang, Yuan; Zhou, Xiaobo; Wang, Honghui; Li, King; Yao, Lixiu; Wong, Stephen T C

    2008-07-01

    Mass spectrometry (MS) has shown great potential in detecting disease-related biomarkers for early diagnosis of stroke. To discover potential biomarkers from large volume of noisy MS data, peak detection must be performed first. This article proposes a novel automatic peak detection method for the stroke MS data. In this method, a mixture model is proposed to model the spectrum. Bayesian approach is used to estimate parameters of the mixture model, and Markov chain Monte Carlo method is employed to perform Bayesian inference. By introducing a reversible jump method, we can automatically estimate the number of peaks in the model. Instead of separating peak detection into substeps, the proposed peak detection method can do baseline correction, denoising and peak identification simultaneously. Therefore, it minimizes the risk of introducing irrecoverable bias and errors from each substep. In addition, this peak detection method does not require a manually selected denoising threshold. Experimental results on both simulated dataset and stroke MS dataset show that the proposed peak detection method not only has the ability to detect small signal-to-noise ratio peaks, but also greatly reduces false detection rate while maintaining the same sensitivity. PMID:18586741

  17. Assessment of actinide mass embedded in large concrete waste packages by photon interrogation and photofission.

    PubMed

    Gmar, M; Jeanneau, F; Lainé, F; Makil, H; Poumarède, B; Tola, F

    2005-01-01

    This paper describes a method based on photofission developed in our laboratory to characterize in depth large waste packages. The method consists in using photons of high-energy (Bremsstrahlung radiation) in order to induce reactions of photofission on the heavy nuclei present in the wastes. The measurement of the delayed neutrons allows quantifying the actinides in the wastes. We present the first results of measurement performed with a concrete mock-up of 870l and two real waste packages. PMID:15982895

  18. Assessment of actinide mass embedded in large concrete waste packages by photon interrogation and photofission.

    PubMed

    Gmar, M; Jeanneau, F; Lainé, F; Makil, H; Poumarède, B; Tola, F

    2005-01-01

    This paper describes a method based on photofission developed in our laboratory to characterize in depth large waste packages. The method consists in using photons of high-energy (Bremsstrahlung radiation) in order to induce reactions of photofission on the heavy nuclei present in the wastes. The measurement of the delayed neutrons allows quantifying the actinides in the wastes. We present the first results of measurement performed with a concrete mock-up of 870l and two real waste packages.

  19. Corrosion-resistant sulfur concretes

    NASA Astrophysics Data System (ADS)

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

    1983-04-01

    Sulfur concretes have been developed by the Bureau of Mines as construction materials with physical and mechanical properties that suit them for use in acid and salt corrosive environments where conventional concretes fail. Mixture design methods were established for preparing sulfur concretes using different types of aggregates and recently developed mixed-modified sulfur cements. Bench-scale testing of the sulfur concretes has shown their potential value. Corrosion resistance, strength, and durability of sulfur concrete are superior to those of conventional materials. Field in situ evaluation tests of the sulfur concretes as replacement for conventional concrete materials are in progress in corrosive areas of 24 commercial chemical, fertilizer, and metallurgical plants.

  20. Stability analyses of the mass abrasive projectile high-speed penetrating into concrete target. Part II: Structural stability analyses

    NASA Astrophysics Data System (ADS)

    Wu, Hao; Chen, Xiao-Wei; Fang, Qin; He, Li-Lin

    2014-12-01

    The initial oblique and attacking angles as well as the asymmetrical nose abrasion may lead to bending or even fracture of a projectile, and the penetration efficiency decreases distinctly. The structural stability of a high-speed projectile non-normally penetrating into concrete and the parametric influences involved are analyzed with the mass abrasion taken into account. By considering the symmetrical or asymmetrical nose abrasion as well as the initial oblique and attacking angles, both the axial and the transverse drag forces acting on the projectile are derived. Based on the ideal elastic-plastic yield criterion, an approach is proposed for predicting the limit striking velocity (LSV) that is the highest velocity at which no yielding failure has occurred and the projectile can still maintain its integral structural stability. Furthermore, some particular penetration scenarios are separately discussed in detail. Based on the engineering model for the mass loss and nose-blunting of ogive-nose projectiles established in Part I of this study, the above approach is validated by several high-speed penetration tests. The analysis on parametric influences indicates that the LSV is reduced with an increase in the asymmetrical nose abrasion, the length-diameter-ratio, and the concrete strength, as well as the oblique and attacking angles. Also, the LSV raises with an increase in the initial caliber-radius-head (CRH) and the dimensionless cartridge thickness of a projectile.

  1. How Concrete Is Concrete?

    ERIC Educational Resources Information Center

    Gravemeijer, Koeno

    2011-01-01

    If we want to make something concrete in mathematics education, we are inclined introduce, what we call, "manipulatives", in the form of tactile objects or visual representations. If we want to make something concrete in a everyday-life conversation, we look for an example. In the former, we try to make a concrete model of our own,…

  2. Introducing Students to Gas Chromatography-Mass Spectrometry Analysis and Determination of Kerosene Components in a Complex Mixture

    ERIC Educational Resources Information Center

    Pacot, Giselle Mae M.; Lee, Lyn May; Chin, Sung-Tong; Marriott, Philip J.

    2016-01-01

    Gas chromatography-mass spectrometry (GC-MS) and GC-tandem MS (GC-MS/MS) are useful in many separation and characterization procedures. GC-MS is now a common tool in industry and research, and increasingly, GC-MS/MS is applied to the measurement of trace components in complex mixtures. This report describes an upper-level undergraduate experiment…

  3. Efimov physics in an ultracold Bose-Fermi mixture with large mass imbalance

    NASA Astrophysics Data System (ADS)

    Weidemueller, Matthias

    2015-05-01

    An ultracold Bose-Fermi mixture of Cs and Li atoms constitutes a prototypical system with large mass imbalance that allows the exploration of many intriguing phenomena in few- and many-body physics. One of such is the heteronuclear Efimov effect, due to which an infinite geometrical series of bound three-body states can be formed, given that the two-body interactions are resonant. Here we present the recent observations of consecutive Efimov resonances through measurements of three-body loss coefficients near the broad Feshbach resonance. A refined analysis of the Feshbach resonance allows us to obtain an improved determination of the scaling of the Efimov resonances, which slightly deviates from the predicted universal scaling factor for the LiCs system. In a recent study, we have determined the effect of the Cs-Cs scattering length on the three-body parameter of the Efimov resonances. Work supported in part by the Heidelberg Center for Quantum Dynamics and the Landesstiftung Baden-Wuerttemberg.

  4. Quantification of influenza virus hemagglutinins in complex mixtures using isotope dilution tandem mass spectrometry.

    PubMed

    Williams, Tracie L; Luna, Leah; Guo, Zhu; Cox, Nancy J; Pirkle, James L; Donis, Ruben O; Barr, John R

    2008-05-12

    Influenza vaccination is the primary method for preventing influenza and its severe complications. Licensed inactivated vaccines for seasonal or pandemic influenza are formulated to contain a preset amount of hemagglutinin (HA), the critical antigen to elicit protection. Current methods to establish the HA concentration of vaccines rely on indirect measurements that are subject to considerable experimental variability. We present a liquid chromatography-tandem mass spectrometry (LC/MS/MS) method for the absolute quantification of viral proteins in a complex mixture. Through use of an isotope dilution approach, HA from viral subtypes H1, H3, H5, and B was determined both directly and rapidly. This method can be applied to purified virus preparations, to monovalent bulk concentrates, or to trivalent inactivated influenza vaccines with improved speed, sensitivity, precision, and accuracy. This LC/MS/MS approach may substantially increase the reliability of methods used to quantitate the amount of antigen in seasonal and pandemic influenza vaccines and reduce the time and effort to deliver influenza vaccines for public health use during the next influenza pandemic.

  5. Enantiomer-specific analysis of multi-component mixtures by correlated electron imaging–ion mass spectrometry

    PubMed Central

    Fanood, Mohammad M Rafiee; Ram, N. Bhargava; Lehmann, C. Stefan; Powis, Ivan; Janssen, Maurice H. M.

    2015-01-01

    Simultaneous, enantiomer-specific identification of chiral molecules in multi-component mixtures is extremely challenging. Many established techniques for single-component analysis fail to provide selectivity in multi-component mixtures and lack sensitivity for dilute samples. Here we show how enantiomers may be differentiated by mass-selected photoelectron circular dichroism using an electron–ion coincidence imaging spectrometer. As proof of concept, vapours containing ∼1% of two chiral monoterpene molecules, limonene and camphor, are irradiated by a circularly polarized femtosecond laser, resulting in multiphoton near-threshold ionization with little molecular fragmentation. Large chiral asymmetries (2–4%) are observed in the mass-tagged photoelectron angular distributions. These asymmetries switch sign according to the handedness (R- or S-) of the enantiomer in the mixture and scale with enantiomeric excess of a component. The results demonstrate that mass spectrometric identification of mixtures of chiral molecules and quantitative determination of enantiomeric excess can be achieved in a table-top instrument. PMID:26104140

  6. Enantiomer-specific analysis of multi-component mixtures by correlated electron imaging-ion mass spectrometry

    NASA Astrophysics Data System (ADS)

    Fanood, Mohammad M. Rafiee; Ram, N. Bhargava; Lehmann, C. Stefan; Powis, Ivan; Janssen, Maurice H. M.

    2015-06-01

    Simultaneous, enantiomer-specific identification of chiral molecules in multi-component mixtures is extremely challenging. Many established techniques for single-component analysis fail to provide selectivity in multi-component mixtures and lack sensitivity for dilute samples. Here we show how enantiomers may be differentiated by mass-selected photoelectron circular dichroism using an electron-ion coincidence imaging spectrometer. As proof of concept, vapours containing ~1% of two chiral monoterpene molecules, limonene and camphor, are irradiated by a circularly polarized femtosecond laser, resulting in multiphoton near-threshold ionization with little molecular fragmentation. Large chiral asymmetries (2-4%) are observed in the mass-tagged photoelectron angular distributions. These asymmetries switch sign according to the handedness (R- or S-) of the enantiomer in the mixture and scale with enantiomeric excess of a component. The results demonstrate that mass spectrometric identification of mixtures of chiral molecules and quantitative determination of enantiomeric excess can be achieved in a table-top instrument.

  7. Quick-setting concrete and a method for making quick-setting concrete

    DOEpatents

    Wagh, Arun S.; Singh, Dileep; Pullockaran, Jose D.; Knox, Lerry

    1997-01-01

    A method for producing quick setting concrete is provided comprising hydrng a concrete dry mixture with carbonate solution to create a slurry, and allowing the slurry to cure. The invention also provides for a quick setting concrete having a predetermined proportion of CaCO.sub.3 of between 5 and 23 weight percent of the entire concrete mixture, and whereby the concrete has a compression strength of approximately 4,000 pounds per square inch (psi) within 24 hours after pouring.

  8. Refractory concretes

    DOEpatents

    Holcombe, Jr., Cressie E.

    1979-01-01

    Novel concrete compositions comprise particles of aggregate material embedded in a cement matrix, said cement matrix produced by contacting an oxide selected from the group of Y.sub.2 O.sub.3, La.sub.2 O.sub.3, Nd.sub.2 O.sub.3, Sm.sub.2 O.sub.3, Eu.sub.2 O.sub.3 and Gd.sub.2 O.sub.3 with an aqueous solution of a salt selected from the group of NH.sub.4 NO.sub.3, NH.sub.4 Cl, YCl.sub.3 and Mg(NO.sub.3).sub.2 to form a fluid mixture; and allowing the fluid mixture to harden.

  9. Complex mixture analysis based on gas chromatography-mass spectrometry with time array detection using a beam deflection time-of-flight mass spectrometer.

    PubMed

    Schultz, G A; Chamberlin, B A; Sweeley, C C; Watson, J T; Allison, J

    1992-01-31

    A beam deflection time-of-flight mass spectrometer was developed in conjunction with an integrating transient recorder to provide time array detection, permitting high mass spectral scan file acquisition rates for complex mixture analysis by capillary gas chromatography-mass spectrometry (GC-MS). Results are presented for the analysis of a urinary organic acid mixture by GC-MS at a scan file acquisition rate of 10 scan files per second (sf/s), showing the advantages of such data collection in the deconvolution of partially resolved components. The reconstructed total ion current (RTIC) chromatogram available from data acquired at this scan file generation rate is shown to be comparable to the profile obtained from a flame ionization detector in representing the chromatography performed under identical experimental parameters. The RTIC chromatogram available from the database obtained at 10 sf/s is compared with that available from a database obtained at 1 sf/s, the latter representing that scan rate typically used with most GC-MS instruments. The advantages of the higher scan file acquisition rate in representing the chromatographic profile and in allowing mass spectral data to be obtained for components in the complex mixture that are unresolved chromatographically are discussed.

  10. Improved Resolution of Hydrocarbon Structures and Constitutional Isomers in Complex Mixtures Using Gas Chromatography-Vacuum Ultraviolet-Mass Spectrometry

    SciTech Connect

    Isaacman, Gabriel; Wilson, Kevin R.; Chan, Arthur W. H.; Worton, David R.; Kimmel, Joel R.; Nah, Theodora; Hohaus, Thorsten; Gonin, Marc; Kroll, Jesse H.; Worsnop, Douglas R.; Goldstein, Allen H.

    2012-01-30

    Understanding the composition of complex hydrocarbon mixtures is important for environmental studies in a variety of fields, but many prevalent compounds cannot be confidently identified using traditional gas chromatography/mass spectrometry (GC/MS) techniques. In this study, we use vacuum-ultraviolet (VUV) ionization to elucidate the structures of a traditionally “unresolved complex mixture” by separating components by GC retention time, tR, and mass-to-charge ratio, m/z, which are used to determine carbon number, NC, and the number of rings and double bonds, NDBE. Constitutional isomers are resolved on the basis of tR, enabling the most complete quantitative analysis to date of structural isomers in an environmentally relevant hydrocarbon mixture. Unknown compounds are classified in this work by carbon number, degree of saturation, presence of rings, and degree of branching, providing structural constraints. The capabilities of this analysis are explored using diesel fuel, in which constitutional isomer distribution patterns are shown to be reproducible between carbon numbers and follow predictable rules. Nearly half of the aliphatic hydrocarbon mass is shown to be branched, suggesting branching is more important in diesel fuel than previously shown. Lastly, the classification of unknown hydrocarbons and the resolution of constitutional isomers significantly improves resolution capabilities for any complex hydrocarbon mixture.

  11. Optical cell with periodic resistive heating for the measurement of heat, mass, and thermal diffusions in liquid mixtures.

    PubMed

    Hartung, M; Köhler, W

    2007-08-01

    A new technique for the measurement of heat, mass, and thermal diffusions in liquids has been developed. Similar to laser induced dynamic gratings, a temperature grating is created in the sample. Thermal expansion transforms the temperature into a refractive-index grating, which is read by diffraction of a readout laser beam. In a multicomponent mixture an additional concentration grating is formed by thermal diffusion driven by the temperature gradients of the temperature grating. Differently to laser induced dynamic grating experiments we use Joule heating instead of optical heating. For that purpose we have built cuvettes which have a grating of transparent conducting strips on the inner side of one of their windows. If heated by an electric current a temperature grating will build up in the sample. Both the heat equation and the extended diffusion equation have been solved in two dimensions to allow for quantitative data analysis. Our apparatus and method of analysis have been validated by measurements of heat, mass, and thermal diffusions in pure and binary liquids. Heat diffusion can be correctly determined as was shown for pure toluene, pure dodecane, and the symmetric mixture of isobutylbenzene dodecane. Mass and thermal diffusions were studied in the three symmetric mixtures of dodecane, isobutylbenzene, and tetralin. The obtained diffusion and Soret coefficients agree with the literature values within the experimental errors. Uncompensated transient heating effects limit the resolution of the experimental technique.

  12. Multiscale Constitutive Modeling of Asphalt Concrete

    NASA Astrophysics Data System (ADS)

    Underwood, Benjamin Shane

    Multiscale modeling of asphalt concrete has become a popular technique for gaining improved insight into the physical mechanisms that affect the material's behavior and ultimately its performance. This type of modeling considers asphalt concrete, not as a homogeneous mass, but rather as an assemblage of materials at different characteristic length scales. For proper modeling these characteristic scales should be functionally definable and should have known properties. Thus far, research in this area has not focused significant attention on functionally defining what the characteristic scales within asphalt concrete should be. Instead, many have made assumptions on the characteristic scales and even the characteristic behaviors of these scales with little to no support. This research addresses these shortcomings by directly evaluating the microstructure of the material and uses these results to create materials of different characteristic length scales as they exist within the asphalt concrete mixture. The objectives of this work are to; 1) develop mechanistic models for the linear viscoelastic (LVE) and damage behaviors in asphalt concrete at different length scales and 2) develop a mechanistic, mechanistic/empirical, or phenomenological formulation to link the different length scales into a model capable of predicting the effects of microstructural changes on the linear viscoelastic behaviors of asphalt concrete mixture, e.g., a microstructure association model for asphalt concrete mixture. Through the microstructural study it is found that asphalt concrete mixture can be considered as a build-up of three different phases; asphalt mastic, fine aggregate matrix (FAM), and finally the coarse aggregate particles. The asphalt mastic is found to exist as a homogenous material throughout the mixture and FAM, and the filler content within this material is consistent with the volumetric averaged concentration, which can be calculated from the job mix formula. It is also

  13. Tailored ion radius distribution for increased dynamic range in FT-ICR mass analysis of complex mixtures.

    PubMed

    Kaiser, Nathan K; McKenna, Amy M; Savory, Joshua J; Hendrickson, Christopher L; Marshall, Alan G

    2013-01-01

    Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) typically utilizes an m/z-independent excitation magnitude to excite all ions to the same cyclotron radius, so that the detected signal magnitude is directly proportional to the relative ion abundance. However, deleterious space charge interaction between ion clouds is maximized for clouds of equal radius. To minimize ion cloud interactions, we induce an m/z-dependent ion radius distribution (30%-45% of the maximum cell radius) that results in a 3-fold increase in mass spectral dynamic range for complex mixtures, consistent with increased ion cloud lifetime for less-abundant ion clouds. Further, broadband frequency-sweep (chirp) excitation that contains the second and/or third harmonic frequency of an excited ion cloud swept from low-to-high frequency produces systematic variations in accurate mass measurement not observed when the sweep direction is reversed. The ion cyclotron radius distribution induces an m/z-dependent frequency shift that can be corrected to provide a root-mean-square (rms) mass measurement error of <100 ppb on petroleum-based mixtures that contain tens of thousands of identified peaks.

  14. A NEW MASS SPECTROMETRIC TECHNIQUE FOR IDENTIFYING TRACE-LEVEL ORGANIC COMPOUNDS IN COMPLEX MIXTURES

    EPA Science Inventory



    Most organic compounds are not found in mass spectral libraries and cannot be easily identified from low resolution mass spectra. Ion Composition Elucidation (ICE) utilizes selected ion recording with a double focusing mass spectrometer in a new way to determine exact mas...

  15. Larger phylogenetic distances in litter mixtures: lower microbial biomass and higher C/N ratios but equal mass loss

    PubMed Central

    Pan, Xu; Berg, Matty P.; Butenschoen, Olaf; Murray, Phil J.; Bartish, Igor V.; Cornelissen, Johannes H. C.; Dong, Ming; Prinzing, Andreas

    2015-01-01

    Phylogenetic distances of coexisting species differ greatly within plant communities, but their consequences for decomposers and decomposition remain unknown. We hypothesized that large phylogenetic distance of leaf litter mixtures increases differences of their litter traits, which may, in turn, result in increased resource complementarity or decreased resource concentration for decomposers and hence increased or decreased chemical transformation and reduction of litter. We conducted a litter mixture experiment including 12 common temperate tree species (evolutionarily separated by up to 106 Myr), and sampled after seven months, at which average mass loss was more than 50%. We found no effect of increased phylogenetic distance on litter mass loss or on abundance and diversity of invertebrate decomposers. However, phylogenetic distance decreased microbial biomass and increased carbon/nitrogen (C/N) ratios of litter mixtures. Consistently, four litter traits showed (marginally) significant phylogenetic signal and in three of these traits increasing trait difference decreased microbial biomass and increased C/N. We suggest that phylogenetic proximity of litter favours microbial decomposers and chemical transformation of litter owing to a resource concentration effect. This leads to a new hypothesis: closely related plant species occurring in the same niche should promote and profit from increased nutrient availability. PMID:25876845

  16. Enzyme-coupled nanoparticles-assisted laser desorption ionization mass spectrometry for searching for low-mass inhibitors of enzymes in complex mixtures.

    PubMed

    Salwiński, Aleksander; Da Silva, David; Delépée, Raphaël; Maunit, Benoît

    2014-04-01

    In this report, enzyme-coupled magnetic nanoparticles (EMPs) were shown to be an effective affinity-based tool for finding specific interactions between enzymatic targets and the low-mass molecules in complex mixtures using classic MALDI-TOF apparatus. EMPs used in this work act as nonorganic matrix enabling ionization of small molecules without any interference in the low-mass range (enzyme-coupled nanoparticles-assisted laser desorption ionization MS, ENALDI MS) and simultaneously carry the superficial specific binding sites to capture inhibitors present in a studied mixture. We evaluated ENALDI approach in two complementary variations: 'ion fading' (IF-ENALDI), based on superficial adsorption of inhibitors and 'ion hunting' (IH-ENALDI), based on selective pre-concentration of inhibitors. IF-ENALDI was applied for two sets of enzyme-inhibitor pairs: tyrosinase-glabridin and trypsin-leupeptin and for the real plant sample: Sparrmannia discolor leaf and stem methanol extract. The efficacy of IH-ENALDI was shown for the pair of trypsin-leupeptin. Both ENALDI approaches pose an alternative for bioassay-guided fractionation, the common method for finding inhibitors in the complex mixtures.

  17. Enzyme-Coupled Nanoparticles-Assisted Laser Desorption Ionization Mass Spectrometry for Searching for Low-Mass Inhibitors of Enzymes in Complex Mixtures

    NASA Astrophysics Data System (ADS)

    Salwiński, Aleksander; Da Silva, David; Delépée, Raphaël; Maunit, Benoît

    2014-04-01

    In this report, enzyme-coupled magnetic nanoparticles (EMPs) were shown to be an effective affinity-based tool for finding specific interactions between enzymatic targets and the low-mass molecules in complex mixtures using classic MALDI-TOF apparatus. EMPs used in this work act as nonorganic matrix enabling ionization of small molecules without any interference in the low-mass range (enzyme-coupled nanoparticles-assisted laser desorption ionization MS, ENALDI MS) and simultaneously carry the superficial specific binding sites to capture inhibitors present in a studied mixture. We evaluated ENALDI approach in two complementary variations: `ion fading' (IF-ENALDI), based on superficial adsorption of inhibitors and `ion hunting' (IH-ENALDI), based on selective pre-concentration of inhibitors. IF-ENALDI was applied for two sets of enzyme-inhibitor pairs: tyrosinase-glabridin and trypsin-leupeptin and for the real plant sample: Sparrmannia discolor leaf and stem methanol extract. The efficacy of IH-ENALDI was shown for the pair of trypsin-leupeptin. Both ENALDI approaches pose an alternative for bioassay-guided fractionation, the common method for finding inhibitors in the complex mixtures.

  18. METALLURGICAL PROGRAMS: CALCULATION OF MASS FROM VOLUME, DENSITY OF MIXTURES, AND CONVERSION OF ATOMIC TO WEIGHT PERCENT

    NASA Technical Reports Server (NTRS)

    Degroh, H.

    1994-01-01

    The Metallurgical Programs include three simple programs which calculate solutions to problems common to metallurgical engineers and persons making metal castings. The first program calculates the mass of a binary ideal (alloy) given the weight fractions and densities of the pure components and the total volume. The second program calculates the densities of a binary ideal mixture. The third program converts the atomic percentages of a binary mixture to weight percentages. The programs use simple equations to assist the materials staff with routine calculations. The Metallurgical Programs are written in Microsoft QuickBASIC for interactive execution and have been implemented on an IBM PC-XT/AT operating MS-DOS 2.1 or higher with 256K bytes of memory. All instructions needed by the user appear as prompts as the software is used. Data is input using the keyboard only and output is via the monitor. The Metallurgical programs were written in 1987.

  19. Large-scale inhomogeneities in solutions of low molar mass compounds and mixtures of liquids: supramolecular structures or nanobubbles?

    PubMed

    Sedlák, Marián; Rak, Dmytro

    2013-02-28

    In textbooks, undersaturated solutions of low molar mass compounds and mixtures of freely miscible liquids are considered as homogeneous at larger length scales exceeding appreciably dimensions of individual molecules. However, growing experimental evidence reveals that it is not the case. Large-scale structures with sizes on the order of 100 nm are present in solutions and mixtures used in everyday life and research practice, especially in aqueous systems. These mesoscale inhomogeneities are long-lived, and (relatively slow) kinetics of their formation can be monitored upon mixing the components. Nevertheless, the nature of these structures and mechanisms behind their formation are not clear yet. Since it was previously suggested that these can be nanobubbles stabilized by adsorbed solute at the gas/solvent interface, we devote the current study to addressing this question. Static and dynamic light scattering was used to investigate solutions and mixtures prepared at ordinary conditions (equilibrated with air at 1 atm), prepared with degassed solvent, and solutions and mixtures degassed after formation of large structures. The behavior of large structures in strong gravitational centrifugal fields was also investigated. Systems from various categories were chosen for this study: aqueous solutions of an inorganic ionic compound (MgSO4), organic ionic compound (citric acid), uncharged organic compound (urea), and a mixture of water with organic solvent freely miscible with water (tert-butyl alcohol). Obtained results show that these structures are not nanobubbles in all cases. Visualization of large-scale structures via nanoparticle tracking analysis is presented. NTA results confirm conclusions from our previous light scattering work.

  20. Magnetic phases of mass- and population-imbalanced ultracold fermionic mixtures in optical lattices

    NASA Astrophysics Data System (ADS)

    Sotnikov, Andrii; Snoek, Michiel; Hofstetter, Walter

    2013-05-01

    We study magnetic phases of two-component mixtures of ultracold fermions with repulsive interactions in optical lattices in the presence of both hopping and population imbalance by means of dynamical mean-field theory (DMFT). It is shown that these mixtures can have easy-axis antiferromagnetic, ferrimagnetic, charge-density wave, and canted-antiferromagnetic order or be unordered depending on parameters of the system. We study the resulting phase diagram in detail and investigate the stability of the different phases with respect to thermal fluctuations. We also perform a quantitative analysis for a gas confined in a harmonic trap, both within the local density approximation and using a full real-space generalization of DMFT.

  1. Two-dimensional mass defect matrix plots for mapping genealogical links in mixtures of lignin depolymerisation products.

    PubMed

    Qi, Yulin; Hempelmann, Rolf; Volmer, Dietrich A

    2016-07-01

    Lignin is the second most abundant natural biopolymer, and lignin wastes are therefore potentially significant sources for renewable chemicals such as fuel compounds, as alternatives to fossil fuels. Waste valorisation of lignin is currently limited to a few applications such as in the pulp industry, however, because of the lack of effective extraction and characterisation methods for the chemically highly complex mixtures after decomposition. Here, we have implemented high resolution mass spectrometry and developed two-dimensional mass defect matrix plots as a data visualisation tool, similar to the Kendrick mass defect plots implemented in fields such as petroleomics. These 2D matrix plots greatly simplified the highly convoluted lignin mass spectral data acquired from Fourier transform ion cyclotron resonance (FTICR)-mass spectrometry, and the derived metrics provided confident peak assignments and strongly improved structural mapping of lignin decomposition product series from the various linkages within the lignin polymer after electrochemical decomposition. Graphical Abstract 2D mass defect matrix plot for a lignin sample after decomposition. PMID:27178557

  2. Antifouling marine concrete

    NASA Astrophysics Data System (ADS)

    Mathews, C. W.

    1980-03-01

    Various toxic agents were investigated for their ability to prevent the attachment and growth of marine fouling organisms on concrete. Three methods of incorporating antifoulants into concrete were also studied. Porous aggregate was impregnated with creosote and bis-(tri-n-butyltin) oxide (TBTO) and then used in making the concrete. Cuprous oxide, triphenyltin hydroxide (TPTH), and 2-2-bis-(p-methoxyphenyl)-1,1,1-trichloroethane (methoxychlor) were used as dry additives. Two proprietary formulations were applied as coatings on untreated concrete. Test specimens were exposed at Port Hueneme, Calif. and Key Biscayne, Fla. Efficacy of toxicants was determined by periodically weighing the specimens and the fouling organisms that became attached. Concrete prepared with an aggregate impregnated with a TBTO/creosote mixture demonstrated the best antifouling performance of those specimens exposed for more than 1 year. The two proprietary coatings and the concrete containing methoxychlor, TPTH, and cuprous oxide as dry additives have exhibited good antifouling properties but have been exposed for a shorter time. Also, the strength of concrete prepared using the toxicants was acceptable and the corrosion rate of reinforcing rods did not increase. The concentration of organotin compounds was essentially unchanged in a concrete specimen exposed 6-1/2 years in seawater.

  3. Frost resistance of concrete surfaces coated with waterproofing materials

    NASA Astrophysics Data System (ADS)

    Klovas, A.; Dauksys, M.; Ciuprovaite, G.

    2015-03-01

    Present research lays emphasis on the problem of concrete surface exposed to aggressive surrounding quality. The test was conducted with concrete surfaces coated with different waterproofing materials exposed in solution of 3 % of sodium sulphate. Research was performed according to LST EN 1338:2003 standard requirements. Technological properties of concrete mixture as well as physical-mechanical properties of formed concrete specimens were established. The resistance of concrete to freezing - thawing cycles was prognosticated according to the porosity parameters established by the kinetic of water absorption. Five different waterproofing materials (coatings) such as liquid bitumen-rubber based, elastic fiber-strengthened, silane-siloxane based emulsion, mineral binder based and liquid rubber (caoutchouc) based coatings were used. Losses by mass of coating materials and specimens surface fractures were calculated based on the results of frost resistance test. Open code program "ImageJ" was used for visual analysis of concrete specimens. Based on the results, aggressive surrounding did not influence specimens coated with elastic, fibre-strengthened, mineral materials. On the other hand, specimens coated with liquid rubber (caoutchouc) based material were greatly influenced by aggressive surrounding. The biggest losses of specimen surface concrete (fractures) were obtained with silane-siloxane based emulsion coating. Generally, specimens coated with waterproofing materials were less influenced by aggressive surrounding compared with those without.

  4. Different target surfaces for the analysis of peptides, peptide mixtures and peptide mass fingerprints by AP-MALDI ion trap-mass spectrometry.

    PubMed

    Pittenauer, Ernst; Kassler, Alexander; Haubner, Roland; Allmaier, Günter

    2011-06-10

    The desorption/ionization behavior of individual peptides, an equimolare peptide mixture and a tryptic digest was investigated by AP-MALDI-IT-MS using four different target materials (gold-covered stainless steel (SS), titanium nitride-covered SS, hand-polished SS, and microdiamond-covered hardmetal) under identical conditions. Gold-covered as well as polished SS targets yielded comparable mass spectra for peptides and peptide mixture in the low pMol-range. The first target exhibited superior data down to the 10fMol-range. In contrast, titanium nitride-covered SS and microdiamond-covered hardmetal AP-MALDI-targets yielded poor sensitivity. These observations could be correlated with the surface roughness of the targets determined by 3D-confocal-white-light-microscopy. The roughest surfaces were found for titanium nitride-covered SS and microdiamond-covered hardmetal material showing both poor MS sensitivity. A less rough surface could be determined for the hand-polished SS target and the smoothest surface was found for the gold-covered target yielding the best sensitivity of all surfaces. These differences in the roughness having a strong impact on the ultimate sensitivity obtainable for peptide samples could be corroborated by electron microscopy. A peptide mixture covering a wide range of molecular weights and a tryptic protein digest (from 2-DE) exhibit the same behavior. This clearly indicates that the smooth gold-covered SS target is the surface of choice in AP-MALDI MS proteomics.

  5. Influence of Wetting and Mass Transfer Properties of Organic Chemical Mixtures in Vadose Zone Materials on Groundwater Contamination by Nonaqueous Phase Liquids

    SciTech Connect

    Charles J Werth; Albert J Valocchi, Hongkyu Yoon

    2011-05-21

    Previous studies have found that organic acids, organic bases, and detergent-like chemicals change surface wettability. The wastewater and NAPL mixtures discharged at the Hanford site contain such chemicals, and their proportions likely change over time due to reaction-facilitated aging. The specific objectives of this work were to (1) determine the effect of organic chemical mixtures on surface wettability, (2) determine the effect of organic chemical mixtures on CCl4 volatilization rates from NAPL, and (3) accurately determine the migration, entrapment, and volatilization of organic chemical mixtures. Five tasks were proposed to achieve the project objectives. These are to (1) prepare representative batches of fresh and aged NAPL-wastewater mixtures, (2) to measure interfacial tension, contact angle, and capillary pressure-saturation profiles for the same mixtures, (3) to measure interphase mass transfer rates for the same mixtures using micromodels, (4) to measure multiphase flow and interphase mass transfer in large flow cell experiments, all using the same mixtures, and (5) to modify the multiphase flow simulator STOMP in order to account for updated P-S and interphase mass transfer relationships, and to simulate the impact of CCl4 in the vadose zone on groundwater contamination. Results and findings from these tasks and summarized in the attached final report.

  6. Analysis of Microbial Mixtures by Matrix-assisted Laser Desorption/Ionization time-of-flight Mass Spectrometry

    SciTech Connect

    Wahl, Karen L.; Wunschel, Sharon C.; Jarman, Kristin H.; Valentine, Nancy B.; Petersen, Catherine E.; Kingsley, Mark T.; Zartolas, Kimberly A.; Saenz, Adam J.

    2002-12-15

    Many different laboratories are currently developing mass-spectrometric techniques to analyze and identify microorganisms. However, minimal work has been done with mixtures of bacteria. To demonstrate that microbial mixtures could be analyzed by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS), mixed bacterial cultures were analyzed in a double-blind fashion. Nine different bacterial species currently in our MALDI-MS fingerprint library were used to generate 50 different simulated mixed bacterial cultures similar to that done for an initial blind study previously reported.(1) The samples were analyzed by MALDI-MS with automated data extraction and analysis algorithms developed in our laboratory. The components present in the sample were identified correctly to the species level in all but one of the samples. However, correctly eliminating closely related organisms was challenging for the current algorithms, especially in differentiating Serratia marcescens, Escherichia coli, and Yersinia enterocolitica, which have some similarities in their MALDI-MS fingerprints. Efforts to improve the specificity of the algorithms are in progress.

  7. Analysis of polyaromatic hydrocarbon mixtures with laser ionization gas chromatography/mass spectrometry

    SciTech Connect

    Rhodes, G.; Opsal, R.B.; Meek, J.T.; Reilly, J.P.

    1983-02-01

    Excimer laser induced multiphoton ionization has been utilized for ion generation in capillary gas chromatography/mass spectrometry and the technique applied to the separation and detection of polyaromatic hydrocarbons. Detection limits as low as 200 fg and linearity over a range of 5 x 10/sup +4/ were obtained for the polyaromatic hydrocarbons examined. Multiphoton ionization mass spectra were dominated by parent ions. Selective ionization based upon small differences in ionization potentials has been demonstrated for coeluting chrysene and triphenylene. Instrumental parameters have been investigated to assess improvements in sensitivity.

  8. Mass and size effects in three-dimensional vibrofluidized granular mixtures

    NASA Astrophysics Data System (ADS)

    Krouskop, Peter E.; Talbot, Julian

    2003-08-01

    We examine the steady state properties of binary systems of driven inelastic hard spheres. The spheres, which move under the influence of gravity, are contained in a vertical cylinder with a vibrating base. We computed the trajectories of the spheres using an event-driven molecular dynamics algorithm. In the first part of the study, we chose simulation parameters that match those of experiments published by Wildman and Parker. Various properties computed from the simulation including the density profile, granular temperature, and circulation pattern are in good qualitative agreement with the experiments. We then studied the effect of varying the mass ratio and the size ratio independently while holding the other parameters constant. The mass and size ratio are shown to affect the distribution of the energy. The changes in the energy distributions affect the packing fraction and temperature of each component. The temperature of the heavier component has a nonlinear dependence on the mass of the lighter component, while the temperature of the lighter component is approximately proportional to its mass. The temperature of both components is inversely dependent on the size of the smaller component.

  9. The analysis of aqueous mixtures using liquid chromatography-electrospray mass spectrometry

    SciTech Connect

    Johnson, S.

    1999-02-12

    The focus of this dissertation is the use of chromatographic methods coupled with electrospray mass spectrometry (ES-MS) for the determination of both organic and inorganic compounds in aqueous solutions. The combination of liquid chromatography (LC) methods and ES-MS offers one of the foremost methods for determining compounds in complex aqueous solutions. In this work, LC-ES-MS methods are devised using ion exclusion chromatography, reversed phase chromatography, and ion exchange chromatography, as well as capillary electrophoresis (CE). For an aqueous sample, these LC-ES-MS and CE-ES-MS techniques require no sample preparation or analyte derivatization, which makes it possible to observe a wide variety of analytes as they exist in solution. The majority of this work focuses on the use of LC-ES-MS for the determination of unknown products and intermediates formed during electrochemical incineration (ECI), an experimental waste remediation process. This report contains a general introduction to the project and the general conclusions. Four chapters have been removed for separate processing. Titles are: Chapter 2: Determination of small carboxylic acids by ion exclusion chromatography with electrospray mass spectrometry; Chapter 3: Electrochemical incineration of benzoquinone in aqueous media using a quaternary metal oxide electrode in the absence of a soluble supporting electrolyte; Chapter 4: The determination of electrochemical incineration products of 4-chlorophenol by liquid chromatography-electrospray mass spectrometry; and Chapter 5: Determination of small carboxylic acids by capillary electrophoresis with electrospray mass spectrometry.

  10. Electrokinetic decontamination of concrete

    SciTech Connect

    Lomasney, H.L.; SenGupta, A.K.; Yachmenev, V.

    1996-12-31

    ELECTROSORB Electrokinetic Extraction Technology, developed by ISOTRON Corp., offers a cost-effective approach to treating contaminated concrete. Heavy metals/radionuclides trapped in concrete can be extracted using this process if they are chemically solubilized; solubilizers used are citric acid alone and a mixture of citric and nitric acids. A DC electric field is applied across the contaminated concrete to electrokinetically transport the solubilized contaminants from the concrete pores to a collector on the concrete surface. The collector is an extraction pad laid on the surface. The pad provides confinement for a planar electrode and solubilizer solution; it is operated under a vacuum to hold the pad against the concrete surface. Operation requires little attendance, reducing the workers` health hazards. The process incorporates a mechanism for recycling the solubilizer solution. A field demonstration of the process took place in Building 21 of DOE`s Mound facility in Miamisburg, OH, over 12 days in June 1996. The thorium species present in this building`s concrete floors included ThO{sub 2} and thorium oxalate. The nitric acid was found to facilitate Th extraction.

  11. Antifouling marine concrete

    SciTech Connect

    Vind, H P; Mathews, C W

    1980-07-01

    Various toxic agents were evaluated as the their capability to prevent or inhibit the attachment of marine fouling organisms to concrete. Creosote and bis-(tri-n-butyltin) oxide (TBTO) were impregnated into porous aggregate which was used in making concrete. Cuprous oxide, triphenyltin hydroxide (TPTH), and 2-2-bis-(p-methoxyphenyl)-1,1,1-trichloroethane (methoxychlor) were used as dry additives. Two proprietary formulations were applied as coatings on untreated concrete. Test specimens were exposed at Port Hueneme, CA, and Key Biscayne, FL. The efficacy of toxicants was determined by periodically weighing the adhering fouling organisms. Concrete prepared with an aggregate impregnated with a TBTO/creosote mixture has demonstrated the best antifouling performance of those specimens exposed for more than one year. The two proprietary coatings and the concrete containing methoxychlor, TPTH, and cuprous oxide as dry additives have exhibited good antifouling properties, but they have been exposed for a shorter time. The strength of concrete containing the toxicants was acceptable, and the toxicants did not increase the corrosion rate of reinforcing rods. Organotin compounds were essentially unchanged in concrete specimens exposed 6 1/2 years in seawater.

  12. Antifouling marine concrete

    SciTech Connect

    Vind, H P; Mathews, C W

    1980-07-01

    Various toxic agents were evaluated as to their capability to prevent or inhibit the attachment of marine fouling organisms to concrete for OTEC plants. Creosote and bis-(tri-n-butyltin) oxide (TBTO) were impregnated into porous aggregate which was used in making concrete. Cuprous oxide, triphenyltin hydroxide (TPTH), and 2-2-bis-(p-methoxyphenyl)-1,1,1-trichloroethane (methoxychlor) were used as dry additives. Two proprietary formulations were applied as coatings on untreated concrete. Test specimens were exposed at Port Hueneme, CA, and Key Biscayne, FL. The efficacy of toxicants was determined by periodically weighing the adhering fouling organisms. Concrete prepared with an aggregate impregnated with a TBTO/creosote mixture has demonstrated the best antifouling performance of those specimens exposed for more than one year. The two proprietary coatings and the concrete containing methoxychlor, TPTH, and cuprous oxide as dry additives have exhibited good antifouling properties, but they have been exposed for a shorter time. The strength of concrete containing the toxicants was acceptable, and the toxicants did not increase the corrosion rate of reinforcing rods. Organotin compounds were essentially unchanged in concrete specimens exposed 6-1/2 years in seawater.

  13. Steam injection system for lunar concrete

    NASA Astrophysics Data System (ADS)

    Pakulski, Dennis M.; Knox, Kenneth J.

    Results of lunar concrete research into steam hydration of concrete currently under way at the USAF Academy by the Department of Civil Engineering are presented. The use of Design of Experiments methodologies to quantify the effects input factors to a process have on the measured responses of the process is demonstrated. The feasibility of hydrating high alumina cement concrete (mortar) using steam injection is shown; the process yields compressible strengths comparable to Portland cement concrete cast with water. The concrete strength is increased with increasing steam exposure (to a point) and with increased density of the dry cement aggregate mixture. Cure time seems to have little effect on the concrete strength.

  14. A macroscale mixture theory analysis of deposition and sublimation rates during heat and mass transfer in dry snow

    NASA Astrophysics Data System (ADS)

    Hansen, A. C.; Foslien, W. E.

    2015-09-01

    The microstructure of a dry alpine snowpack is a dynamic environment where microstructural evolution is driven by seasonal density profiles and weather conditions. Notably, temperature gradients on the order of 10-20 K m-1, or larger, are known to produce a faceted snow microstructure exhibiting little strength. However, while strong temperature gradients are widely accepted as the primary driver for kinetic growth, they do not fully account for the range of experimental observations. An additional factor influencing snow metamorphism is believed to be the rate of mass transfer at the macroscale. We develop a mixture theory capable of predicting macroscale deposition and/or sublimation in a snow cover under temperature gradient conditions. Temperature gradients and mass exchange are tracked over periods ranging from 1 to 10 days. Interesting heat and mass transfer behavior is observed near the ground, near the surface, as well as immediately above and below dense ice crusts. Information about deposition (condensation) and sublimation rates may help explain snow metamorphism phenomena that cannot be accounted for by temperature gradients alone. The macroscale heat and mass transfer analysis requires accurate representations of the effective thermal conductivity and the effective mass diffusion coefficient for snow. We develop analytical models for these parameters based on first principles at the microscale. The expressions derived contain no empirical adjustments, and further, provide self consistent values for effective thermal conductivity and the effective diffusion coefficient for the limiting cases of air and solid ice. The predicted values for these macroscale material parameters are also in excellent agreement with numerical results based on microscale finite element analyses of representative volume elements generated from X-ray tomography.

  15. A macroscale mixture theory analysis of deposition and sublimation rates during heat and mass transfer in snow

    NASA Astrophysics Data System (ADS)

    Hansen, A. C.; Foslien, W. E.

    2015-03-01

    The microstructure of a dry alpine snowpack is a dynamic environment where microstructural evolution is driven by seasonal density profiles and weather conditions. Notably, temperature gradients on the order of 10-20 K m-1, or larger, are known to produce a faceted snow microstructure exhibiting little strength. However, while strong temperature gradients are widely accepted as the primary driver for kinetic growth, they do not fully account for the range of experimental observations. An additional factor influencing snow metamorphism is believed to be the rate of mass transfer at the macroscale. We develop a mixture theory capable of predicting macroscale deposition and/or sublimation in a snow cover under temperature gradient conditions. Temperature gradients and mass exchange are tracked over periods ranging from 1 to 10 days. Interesting heat and mass transfer behavior is observed near the ground, near the surface, as well as immediately above and below dense ice crusts. Information about deposition (condensation) and sublimation rates may help explain snow metamorphism phenomena that cannot be accounted for by temperature gradients alone. The macroscale heat and mass transfer analysis requires accurate representations of the thermal conductivity and the effective mass diffusion coefficient for snow. We develop analytical models for these parameters based on first principles at the microscale. The expressions derived contain no empirical adjustments, and further, provide self consistent values for thermal conductivity and the effective diffusion coefficient for the limiting cases of air and solid ice. The predicted values for these macroscale material parameters are also in excellent agreement with numerical results based on microscale finite element analyses of representative volume elements generated from X-ray tomography.

  16. Durability of concrete materials in high-magnesium brine

    SciTech Connect

    Wakeley, L.D.; Poole, T.S.; Burkes, J.P.

    1994-03-01

    Cement pastes and mortars representing 11 combinations of candidate concrete materials were cast in the laboratory and monitored for susceptibility to chemical deterioration in high-magnesium brine. Mixtures were selected to include materials included in the current leading candidate concrete for seals at the Waste Isolation Pilot Plant (WIPP). Some materials were included in the experimental matrix to answer questions that had arisen during study of the concrete used for construction of the liner of the WIPP waste-handling shaft. Mixture combinations compared Class C and Class F fly ashes, presence or absence of an expansive component, and presence or absence of salt as a mixture component. Experimental conditions exposed the pastes and mortars to extreme conditions, those being very high levels of Mg ion and an effectively unlimited supply of brine. All pastes and mortars showed deterioration with brine exposure. In general, mortars deteriorated more extensively than the corresponding pastes. Two-inch cube specimens of mortar were not uniformly deteriorated, but showed obvious zoning even after a year in the brine, with a relatively unreacted zone remaining at the center of each cube. Loss of calcium from the calcium hydroxide of paste/aggregate interfaces caused measurable strength loss in the reacted zone comprising the outer portion of every mortar specimen. The current candidate mass concrete for WIPP seals includes salt as an initial component, and has a relatively closed initial microstructure. Both of these features contribute to its suitability for use in large placements within the Salado Formation.

  17. Direct Analysis of Triacylglycerols from Crude Lipid Mixtures by Gold Nanoparticle-Assisted Laser Desorption/Ionization Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Son, Jeongjin; Lee, Gwangbin; Cha, Sangwon

    2014-05-01

    Triacylglycerols (TAGs), essential energy storage lipids, are easily detected by conventional MALDI MS when occurring on their own. However, their signals are easily overwhelmed by other lipids, mainly phosphatidylcholines (PCs) and, therefore, require purification. In order to profile TAGs from crude lipid mixtures without prefractionation, we investigated alternative matrixes that can suppress phospholipid ion signals and enhance cationization of TAGs. We found that an aqueous solution of citrate-capped gold nanoparticles (AuNPs) with a diameter of 12 nm is a superior matrix for the laser desorption/ionization mass spectrometry (LDI MS) of TAGs in crude lipid mixtures. The AuNP matrix effectively suppressed other lipid signals such as phospholipids and also provided 100 times lower detection limit for TAGs than 2,5-dihydroxybenzoic acid (DHB), the best conventional MALDI matrix for TAGs. The AuNP-assisted LDI MS enabled us to obtain detailed TAG profiles including minor species directly from crude beef lipid extracts without phospholipid interference. In addition, we could detect TAGs at a trace level from a total brain lipid extract.

  18. Complex mixture analysis by photoionization mass spectrometry with a VUV hydrogen laser source

    NASA Astrophysics Data System (ADS)

    Huth, T. C.; Denton, M. B.

    1985-12-01

    Trace organic analysis in complex matrix presents one of the most challenging problems in analytical mass spectrometry. When ionization is accomplished non-selectively using electron impact, extensive sample clean-up is often necessary in order to isolate the analyte from the matrix. Sample preparation can be greatly reduced when the VUV H2 laser is used to selectively photoionize only a small fraction of compounds introduced into the ion source. This device produces parent ions only for all compounds whose ionization potentials lie below a threshold value determined by the photon energy of 7.8 eV. The only observed interference arises from electron impact ionization, when scattered laser radiation interacts with metal surfaces, producing electrons which are then accelerated by potential fields inside the source. These can be suppressed to levels acceptable for practical analysis through proper instrumental design. Results are presented which indicate the ability of this ion source to discriminate against interfering matrix components, in simple extracts from a variety of complex real world matrices, such as brewed coffee, beer, and urine.

  19. Quick-setting concrete and a method for making quick-setting concrete

    DOEpatents

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

    1997-04-29

    A method for producing quick setting concrete is provided comprising mixing a concrete dry mixture with carbonate solution to create a slurry, and allowing the slurry to cure. The invention also provides for a quick setting concrete having a predetermined proportion of CaCO{sub 3} of between 5 and 23 weight percent of the entire concrete mixture, and whereby the concrete has a compression strength of approximately 4,000 pounds per square inch (psi) within 24 hours after pouring. 2 figs.

  20. Performance of "Waterless Concrete"

    NASA Technical Reports Server (NTRS)

    Toutanji, H. A.; Grugel, R. N.

    2009-01-01

    Waterless concrete consists of molten elementary sulfur and aggregate. The aggregates in a lunar environment will be lunar rocks and soil. Sulfur is present on the Moon in Troilite soil (FeS) and, by oxidation of the soil, iron and sulfur can be produced. Sulfur concrete specimens were cycled between liquid nitrogen (approx.]91 C) and room temperature (^21 C) to simulate exposure to a lunar environment. Cycled and control specimens were subsequently tested in compression at room temperatures (^21 C) and ^-101 C. Test results showed that due to temperature cycling, the compressive strength of cycled specimens was 20% of those non-cycled. This reduction in strength can be attributed to the large differences in thermal coefficients of expansion of the materials constituting the concrete which promoted cracking. Similar sulfur concrete mixtures were strengthened with short and long glass fibres. The lunar regolith simulant was melted in a 25 cc Pt- Rh crucible in a Sybron Thermoline high temperature MoSi2 furnace at melting temperatures of 1450 to 1600 C for times of 30 min to i hour. Glass fibres and small rods were pulled from the melt. The glass fibres were used to reinforce sulfur concrete plated to improve the flexural strength of the sulfur concrete. Beams strengthened with glass fibres showed to exhibit an increase in the flexural strength by as much as 45%.

  1. Characterization of direct current He-N{sub 2} mixture plasma using optical emission spectroscopy and mass spectrometry

    SciTech Connect

    Flores, O.; Castillo, F.; Martinez, H.; Villa, M.; Reyes, P. G.; Villalobos, S.

    2014-05-15

    This study analyses the glow discharge of He and N{sub 2} mixture at the pressure of 2.0 Torr, power of 10 W, and flow rate of 16.5 l/min, by using optical emission spectroscopy and mass spectrometry. The emission bands were measured in the wavelength range of 200–1100 nm. The principal species observed were N{sub 2}{sup +} (B{sup 2}Σ{sup +}{sub u}→X{sup 2}Σ{sup +}{sub g}), N{sub 2} (C{sup 3}Π{sub u}→B{sup 3}Π{sub g}), and He, which are in good agreement with the results of mass spectrometry. Besides, the electron temperature and ion density were determined by using a double Langmuir probe. Results indicate that the electron temperature is in the range of 1.55–2.93 eV, and the electron concentration is of the order of 10{sup 10} cm{sup −3}. The experimental results of electron temperature and ion density for pure N{sub 2} and pure He are in good agreement with the values reported in the literature.

  2. Molecular composition of aged secondary organic aerosol generated from a mixture of biogenic volatile compounds using ultrahigh resolution mass spectrometry

    NASA Astrophysics Data System (ADS)

    Kourtchev, I.; Doussin, J.-F.; Giorio, C.; Mahon, B.; Wilson, E. M.; Maurin, N.; Pangui, E.; Venables, D. S.; Wenger, J. C.; Kalberer, M.

    2015-02-01

    Field observations over the past decade indicate that a significant fraction of organic aerosol in remote areas may contain highly oxidised molecules. Aerosol processing or further oxidation (ageing) of organic aerosol has been suggested to be responsible for their formation through heterogeneous uptake of oxidants and multigenerational oxidation of vapours by OH radicals. In this study we investigated the influence of several ageing processes on the molecular composition of secondary organic aerosols (SOA) using direct infusion and liquid chromatography ultrahigh resolution mass spectrometry. SOA was formed in simulation chamber experiments from ozonolysis of a mixture of four biogenic volatile organic compounds (BVOC): α-pinene, β-pinene, Δ3-carene and isoprene. The SOA was subsequently aged under three different sets of conditions: in the dark in the presence of residual ozone, with UV irradiation and OH radicals, and using UV light only. Among all studied conditions, only OH radical-initiated ageing was found to influence the molecular composition of the aerosol and showed an increase in carbon oxidation state (OSC) and elemental O/C ratios of the SOA components. None of the ageing processes produced an observable effect on the oligomers formed from ozonolysis of the BVOC mixture, which were found to be equally abundant in both "fresh" and "aged" SOA. Additional experiments using α-pinene as the sole precursor demonstrated that oligomers are an important group of compounds in SOA produced from both ozonolysis and OH radical-initiated oxidation processes; however, a completely different set of oligomers is formed under these two oxidation regimes. SOA from the OH radical-initiated α-pinene oxidation had a significantly higher overall OSC and O/C compared to that from pure ozonolysis experiments confirming that the OH radical reaction is more likely to be responsible for the occurrence of highly oxidised species in ambient biogenic SOA.

  3. Stability analyses of the mass abrasive projectile high-speed penetrating into concrete target. Part I: Engineering model for the mass loss and nose-blunting of ogive-nosed projectiles

    NASA Astrophysics Data System (ADS)

    Wu, Hao; Chen, Xiao-Wei; He, Li-Lin; Fang, Qin

    2014-12-01

    The mass loss and nose blunting of a projectile during high-speed deep penetration into concrete target may cause structural destruction and ballistic trajectory instability of the penetrator, obviously reducing the penetration efficiency of penetrator. Provided that the work of friction between projectile and target is totally transformed into the heat to melt penetrator material at its nose surface, an engineering model is established for the mass loss and nose-blunting of the ogive-nosed projectile. A dimensionless formula for the relative mass loss of projectile is obtained by introducing the dimensionless impact function I and geometry function N of the projectile. The critical value V {0/c} of the initial striking velocity is formulated, and the mass loss of projectile tends to increase weakly nonlinearly with I/ N when V 0 < V {0/c}, whilst the mass loss is proportional to the initial kinetic energy of projectile when V 0 < V {0/c}. The theoretical prediction of V {0/c} is further confirmed to be very close to the experimental value of 1.0 km/s based on 11 sets of different penetration tests. Also the validity of the proposed expressions of mass loss and nose-blunting coefficients of a projectile are verified by the tests. Therefore, a theoretical basis is for the empirical conclusions drawn in previous publications. Regarding the completely empirical determinations of the mass loss and nose-blunting coefficients given in previous papers, the present analysis reveals its physical characteristic and also guarantees its prediction accuracy. The engineering model established in the present paper forms the basis for further discussions on the structural stability and the terminal ballistic stability of ogive-nosed projectiles high-speed penetrating into concrete targets, which will respectively be elaborated in Part II and Part III of the present study.

  4. Rapid Characterization of Microalgae and Microalgae Mixtures Using Matrix-Assisted Laser Desorption Ionization Time-Of-Flight Mass Spectrometry (MALDI-TOF MS).

    PubMed

    Barbano, Duane; Diaz, Regina; Zhang, Lin; Sandrin, Todd; Gerken, Henri; Dempster, Thomas

    2015-01-01

    Current molecular methods to characterize microalgae are time-intensive and expensive. Matrix Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS) may represent a rapid and economical alternative approach. The objectives of this study were to determine whether MALDI-TOF MS can be used to: 1) differentiate microalgae at the species and strain levels and 2) characterize simple microalgal mixtures. A common protein extraction sample preparation method was used to facilitate rapid mass spectrometry-based analysis of 31 microalgae. Each yielded spectra containing between 6 and 56 peaks in the m/z 2,000 to 20,000 range. The taxonomic resolution of this approach appeared higher than that of 18S rDNA sequence analysis. For example, two strains of Scenedesmus acutus differed only by two 18S rDNA nucleotides, but yielded distinct MALDI-TOF mass spectra. Mixtures of two and three microalgae yielded relatively complex spectra that contained peaks associated with members of each mixture. Interestingly, though, mixture-specific peaks were observed at m/z 11,048 and 11,230. Our results suggest that MALDI-TOF MS affords rapid characterization of individual microalgae and simple microalgal mixtures.

  5. Rapid Characterization of Microalgae and Microalgae Mixtures Using Matrix-Assisted Laser Desorption Ionization Time-Of-Flight Mass Spectrometry (MALDI-TOF MS)

    PubMed Central

    Barbano, Duane; Diaz, Regina; Zhang, Lin; Sandrin, Todd; Gerken, Henri; Dempster, Thomas

    2015-01-01

    Current molecular methods to characterize microalgae are time-intensive and expensive. Matrix Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS) may represent a rapid and economical alternative approach. The objectives of this study were to determine whether MALDI-TOF MS can be used to: 1) differentiate microalgae at the species and strain levels and 2) characterize simple microalgal mixtures. A common protein extraction sample preparation method was used to facilitate rapid mass spectrometry-based analysis of 31 microalgae. Each yielded spectra containing between 6 and 56 peaks in the m/z 2,000 to 20,000 range. The taxonomic resolution of this approach appeared higher than that of 18S rDNA sequence analysis. For example, two strains of Scenedesmus acutus differed only by two 18S rDNA nucleotides, but yielded distinct MALDI-TOF mass spectra. Mixtures of two and three microalgae yielded relatively complex spectra that contained peaks associated with members of each mixture. Interestingly, though, mixture-specific peaks were observed at m/z 11,048 and 11,230. Our results suggest that MALDI-TOF MS affords rapid characterization of individual microalgae and simple microalgal mixtures. PMID:26271045

  6. Analysis of Phospholipid Mixtures from Biological Tissues by Matrix-Assisted Laser Desorption and Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS): A Laboratory Experiment

    ERIC Educational Resources Information Center

    Eibisch, Mandy; Fuchs, Beate; Schiller, Jurgen; Sub, Rosmarie; Teuber, Kristin

    2011-01-01

    Matrix-assisted laser desorption and ionization time-of-flight mass spectrometry (MALDI-TOF MS) is increasingly used to investigate the phospholipid (PL) compositions of tissues and body fluids, often without previous separation of the total mixture into the individual PL classes. Therefore, the questions of whether all PL classes are detectable…

  7. Examination of Behavior of Fresh Concrete Under Pressure

    NASA Astrophysics Data System (ADS)

    Yücel, K. T.

    2012-05-01

    Transporting fresh concrete constitutes a significant part of the production process. Transferring ready-mixed concrete on-site is done using concrete pumps. Recent developments in concrete technology, and in mineral and chemical additives, have resulted in new developments in pumping techniques and the use of different concrete mixtures and equipment. These developments required further knowledge of the behavior of fresh concrete under pressure. Two criteria were determined for the pumpability of concrete: the power required to move the concrete or of the repulsive force; and the cohesion of the fresh concrete. It would be insufficient to relate pumpability to these two criteria; the values of segregation pressure, diffusion ability, water retention capacity, and side friction of the mixture are significant parameters in ensuring that concrete is pumped freely along the pipe. To solve the pumpability problem, friction stresses should be determined as a function of the linear pressure gradient, the pressure leading to segregation of the fresh concrete should be determined, and tests for the bleeding of concrete under pressure should be examined. The scope of the research is the examination of the behavior of fresh concrete under pressure. To determine the segregation pressures, a test apparatus was designed for the bleeding of concrete under pressure. The main purpose of the study is to determine whether the concrete can be pumped easily and whether it will lose its cohesion during the pumping, based on tests of concrete workability and bleeding of concrete under pressure.

  8. Improved resolution of hydrocarbon structures and constitutional isomers in complex mixtures using Gas Chromatography-Vacuum Ultraviolet-Mass Spectrometry (GC-VUV-MS)

    SciTech Connect

    Aerosol Dynamics Inc; Aerodyne Research, Inc.,; Tofwerk AG, Thun; Isaacman, Gabriel; Wilson, Kevin R.; Chan, Arthur W. H.; Worton, David R.; Kimmel, Joel R.; Nah, Theodora; Hohaus, Thorsten; Gonin, Marc; Kroll, Jesse H.; Worsnop, Doug R.; Goldstein, Allen H.

    2011-09-13

    Understanding the composition of complex hydrocarbon mixtures is important for environmental studies in a variety of fields, but many prevalent compounds cannot be confidently identified using traditional gas chromatography-mass spectrometry (GC-MS) techniques. This work uses vacuum-ultraviolet (VUV) ionization to elucidate the structures of a traditionally"unresolved complex mixture" by separating components by GC retention time, tR, and mass-to-charge ratio, m/Q, which are used to determine carbon number, NC, and the number of rings and double bonds, NDBE. Constitutional isomers are resolved based on tR, enabling the most complete quantitative analysis to date of structural isomers in an environmentally-relevant hydrocarbon mixture. Unknown compounds are classified in this work by carbon number, degree of saturation, presence of rings, and degree of branching, providing structural constraints. The capabilities of this analysis are explored using diesel fuel, in which constitutional isomer distribution patterns are shown to be reproducible between carbon numbers and follow predictable rules. Nearly half of the aliphatic hydrocarbon mass is shown to be branched, suggesting branching is more important in diesel fuel than previously shown. The classification of unknown hydrocarbons and the resolution of constitutional isomers significantly improves resolution capabilities for any complex hydrocarbon mixture.

  9. Quick-setting concrete and a method for making quick-setting concrete

    SciTech Connect

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

    1995-12-31

    This invention relates to a method for producing concrete, and more specifically, this invention relates to a method for producing quick-setting concrete while simultaneously minimizing the release of carbon dioxide to the atmosphere, said release of carbon dioxide inherent in cement production. A method for producing quick setting concrete comprises hydrating a concrete dry mixture with carbonate solution to create a slurry, and allowing the slurry to cure. The invention also provides for a quick setting concrete having a predetermined proportion of CaCO{sub 3} of between 5 and 23 weight percent of the entire concrete mixture, and whereby the concrete has a compression strength of approximately 4,000 pounds per square inch (psi) within 24 hours after pouring.

  10. Structural elucidation of biologically active neomycin N-octyl derivatives in a regioisomeric mixture by means of liquid chromatography/ion trap time-of-flight mass spectrometry.

    PubMed

    Giera, Martin; de Vlieger, Jon S B; Lingeman, Henk; Irth, Hubertus; Niessen, Wilfried M A

    2010-05-30

    Structural elucidation of six regioisomers of mono-N-octyl derivatized neomycin is achieved using MS(n) (up to n = 4) on an ion trap time-of-flight (IT-TOF) instrument equipped with electrospray ionization. The mixture of six derivatized neomycin analogues was generated by reductive amination in a shotgun synthetic approach. In parallel to the liquid chromatography/mass spectrometry (LC/MS) detection, the antibacterial activity of the neomycin regioisomers was tested by post-column addition of buffer and bacterial inocula, subsequent microfractionation of the resulting mixture, incubation, and finally a chemiluminescence-based bioactivity measurement based on the production of bacterial ATP. The MS-based high-resolution screening approach described can be applied in medicinal chemistry to help in designing and producing new antibiotic substances, which is particularly challenging due to the high functionality of most antibiotic substances, therefore requiring advanced (hyphenated) separation and detection techniques for compound mixtures.

  11. Detection of bacteria from biological mixtures using immunomagnetic separation combined with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

    USGS Publications Warehouse

    Madonna, A.J.; Basile, F.; Furlong, E.; Voorhees, K.J.

    2001-01-01

    A rapid method for identifying specific bacteria from complex biological mixtures using immunomagnetic separation coupled to matrix-assisted laser desorption/ionization time-of-flight mass spectrometry has been developed. The technique employs commercially available magnetic beads coated with polycolonal antibodies raised against specific bacteria and whole cell analysis by MALDI-MS. A suspension of a bacterial mixture is mixed with the immunomagnetic beads specific for the target microorganism. After a short incubation period (20 mins) the bacteria captured by the beads are washed, resuspended in deionized H2O and directly applied onto a MALDI probe. Liquid suspensions containing bacterial mixtures can be screened within 1 h total analysis time. Positive tests result in the production of a fingerprint mass spectrum primarily consisting of protein biomarkers characteristic of the targeted microorganism. Using this procedure, Salmonella choleraesuis was isolated and detected from standard bacterial mixtures and spiked samples of river water, human urine, and chicken blood. Copyright ?? 2001 John Wiley & Sons, Ltd.

  12. Bacterial concrete

    NASA Astrophysics Data System (ADS)

    Ramakrishnan, Venkataswamy; Ramesh, K. P.; Bang, S. S.

    2001-04-01

    Cracks in concrete are inevitable and are one of the inherent weaknesses of concrete. Water and other salts seep through these cracks, corrosion initiates, and thus reduces the life of concrete. So there was a need to develop an inherent biomaterial, a self-repairing material which can remediate the cracks and fissures in concrete. Bacterial concrete is a material, which can successfully remediate cracks in concrete. This technique is highly desirable because the mineral precipitation induced as a result of microbial activities is pollution free and natural. As the cell wall of bacteria is anionic, metal accumulation (calcite) on the surface of the wall is substantial, thus the entire cell becomes crystalline and they eventually plug the pores and cracks in concrete. This paper discusses the plugging of artificially cracked cement mortar using Bacillus Pasteurii and Sporosarcina bacteria combined with sand as a filling material in artificially made cuts in cement mortar which was cured in urea and CaCl2 medium. The effect on the compressive strength and stiffness of the cement mortar cubes due to the mixing of bacteria is also discussed in this paper. It was found that use of bacteria improves the stiffness and compressive strength of concrete. Scanning electron microscope (SEM) is used to document the role of bacteria in microbiologically induced mineral precipitation. Rod like impressions were found on the face of calcite crystals indicating the presence of bacteria in those places. Energy- dispersive X-ray (EDX) spectra of the microbial precipitation on the surface of the crack indicated the abundance of calcium and the precipitation was inferred to be calcite (CaCO3).

  13. Mass Transport Properties of LiD-U Mixtures from Orbital Free Molecular Dynamics Simulations and a Pressure-Matching Mixing Rule

    SciTech Connect

    Burakovsky, Leonid; Kress, Joel D.; Collins, Lee A.

    2012-05-31

    Mass transport properties for LiD-U mixtures were calculated using a pressure matching mixture rule for the mixing of LiD and of U properties simulated with Orbital Free Molecular Dynamics (OFMD). The mixing rule was checked against benchmark OFMD simulations for the fully interacting three-component (Li, D, U) system. To obtain transport coefficients for LiD-U mixtures of different (LiD){sub x}U{sub (1-x)} compositions as functions of temperature and mixture density is a tedious task. Quantum molecular dynamics (MD) simulations can be employed, as in the case LiD or U. However, due to the presence of the heavy constituent U, such simulations proceed so slowly that only a limited number of numerical data points in the (x, {rho}, T) phase space can be obtained. To finesse this difficulty, transport coefficients for a mixture can be obtained using a pressure-matching mixing rule discussed. For both LiD and U, the corresponding transport coefficients were obtained earlier from quantum molecular dynamics simulations. In these simulations, the quantum behavior of the electrons was represented using an orbital free (OF) version of density functional theory, and ions were advanced in time using classical molecular dynamics. The total pressure of the system, P = nk{sub B}T/V + P{sub e}, is the sum of the ideal gas pressure of the ions plus the electron pressure. The mass self-diffusion coefficient for species {alpha}, D{sub {alpha}}, the mutual diffusion coefficient for species {alpha} and {beta}, D{alpha}{beta}, and the shear viscosity, {eta}, are computed from the appropriate autocorrelation function. The details of similar QMD calculations on LiH are described in Ref. [1] for 0.5 eV < T < 3 eV, and in Ref. [2] for 2 eV < T < 6 eV.

  14. Moisture damage in asphalt concrete. Final report

    SciTech Connect

    Not Available

    1991-10-01

    Information is provided on physical and chemical explanations for moisture damage in asphalt concrete, along with a discussion of current practices and test methods for determining or reducing the susceptibility of various asphalt concrete components and mixtures to such damage. Moisture damage in asphalt concrete is a nationwide problem which often necessitates premature replacement of highway pavement surfaces. The report of the Transportation Research Board describes the underlying physical and chemical phenomena responsible for such damage. Current test methods used to determine the susceptibility of asphalt concretes, or their constituents, to moisture damage are described and evaluated. Additionally, current practices for minimizing the potential for moisture damage are examined.

  15. Assessment of deterioration in RHA-concrete due to magnesium sulphate attack

    NASA Astrophysics Data System (ADS)

    Habeeb, G. A.; Mahmud, H. B.; Hamid, N. B. A. A.

    2010-12-01

    The assessment of magnesium sulphate attack on concretes containing rice husk ash (RHA, 20wt% of the cementitious materials) with various average particle sizes was investigated. The total cementitious materials were 390 kg and the water-to-binder ratio (W/B) was 0.53 for all mixtures. Specimens were initially cured in water for 7 d and then immersed in the 3wt% magnesium sulphate solution for up to 111 d of exposure. The specimens were subjected to drying-wetting cycles to accelerate sulphate attack. In addition to the visual monitoring of the specimens, the concrete specimens were subsequently tested for compressive strength, dynamic modulus of elasticity, and length and mass changes. The results show that the specimens exposed to sulphate attack exhibit higher strength and dynamic modulus than those kept in water. The length change is negligible and can be attributed to the normal swelling of concrete. On the other hand, concretes suffers mass loss and surface spalling and softening; the fine RHA-concrete results in a better resistance. For the accelerated sulphate attack method used in this study, mass change and visual monitoring are recommended for assessing the deterioration degree and the effectiveness of supplementary cementitious materials to resist sulphate attack.

  16. Solid-phase microextraction low temperature plasma mass spectrometry for the direct and rapid analysis of chemical warfare simulants in complex mixtures.

    PubMed

    Dumlao, Morphy C; Jeffress, Laura E; Gooding, J Justin; Donald, William A

    2016-06-21

    Solid-phase microextraction (SPME) is directly integrated with low temperature plasma ionisation mass spectrometry to rapidly detect organophosphate chemical warfare agent simulants and their hydrolysis products in chemical mixtures, including urine. In this sampling and ionization method, the fibre serves: (i) to extract molecules from their native environment, and (ii) as the ionization electrode that is used to desorb and ionize molecules directly from the SPME surface. By use of a custom fabricated SPME fibre consisting of a stainless steel needle coated with a Linde Type A (LTA) zeolitic microporous material and low temperature plasma mass spectrometry, protonated dimethyl methylphosphonate (DMMP), diethyl ethylphosphonate (DEEP) and pinacolyl methylphosphonic acid (PinMPA) can be detected at less than 100 ppb directly in water and urine. Organophosphates were not readily detected by this approach using an uncoated needle in negative control experiments. The use of the LTA coating significantly outperformed the use of a high alumina Zeolite Socony Mobil-5 (ZSM-5) coating of comparable thickness that is significantly less polar than LTA. By conditioning the LTA probe by immersion in an aqueous CuSO4 solution, the ion abundance for protonated DMMP increased by more than 300% compared to that obtained without any conditioning. Sample recovery values were between 96 and 100% for each analyte. The detection of chemical warfare agent analogues and hydrolysis products required less than 2 min per sample. A key advantage of this sampling and ionization method is that analyte ions can be directly and rapidly sampled from chemical mixtures, such as urine and seawater, without sample preparation or chromatography for sensitive detection by mass spectrometry. This ion source should prove beneficial for portable mass spectrometry applications because relatively low detection limits can be obtained without the use of compressed gases, fluid pumps, and lasers. Moreover, the

  17. Solid-phase microextraction low temperature plasma mass spectrometry for the direct and rapid analysis of chemical warfare simulants in complex mixtures.

    PubMed

    Dumlao, Morphy C; Jeffress, Laura E; Gooding, J Justin; Donald, William A

    2016-06-21

    Solid-phase microextraction (SPME) is directly integrated with low temperature plasma ionisation mass spectrometry to rapidly detect organophosphate chemical warfare agent simulants and their hydrolysis products in chemical mixtures, including urine. In this sampling and ionization method, the fibre serves: (i) to extract molecules from their native environment, and (ii) as the ionization electrode that is used to desorb and ionize molecules directly from the SPME surface. By use of a custom fabricated SPME fibre consisting of a stainless steel needle coated with a Linde Type A (LTA) zeolitic microporous material and low temperature plasma mass spectrometry, protonated dimethyl methylphosphonate (DMMP), diethyl ethylphosphonate (DEEP) and pinacolyl methylphosphonic acid (PinMPA) can be detected at less than 100 ppb directly in water and urine. Organophosphates were not readily detected by this approach using an uncoated needle in negative control experiments. The use of the LTA coating significantly outperformed the use of a high alumina Zeolite Socony Mobil-5 (ZSM-5) coating of comparable thickness that is significantly less polar than LTA. By conditioning the LTA probe by immersion in an aqueous CuSO4 solution, the ion abundance for protonated DMMP increased by more than 300% compared to that obtained without any conditioning. Sample recovery values were between 96 and 100% for each analyte. The detection of chemical warfare agent analogues and hydrolysis products required less than 2 min per sample. A key advantage of this sampling and ionization method is that analyte ions can be directly and rapidly sampled from chemical mixtures, such as urine and seawater, without sample preparation or chromatography for sensitive detection by mass spectrometry. This ion source should prove beneficial for portable mass spectrometry applications because relatively low detection limits can be obtained without the use of compressed gases, fluid pumps, and lasers. Moreover, the

  18. Use of Residual Solids from Pulp and Paper Mills for Enhancing Strength and Durability of Ready-Mixed Concrete

    SciTech Connect

    Tarun R. Naik; Yoon-moon Chun; Rudolph N. Kraus

    2003-09-18

    This research was conducted to establish mixture proportioning and production technologies for ready-mixed concrete containing pulp and paper mill residual solids and to study technical, economical, and performance benefits of using the residual solids in the concrete. Fibrous residuals generated from pulp and paper mills were used, and concrete mixture proportions and productions technologies were first optimized under controlled laboratory conditions. Based on the mixture proportions established in the laboratory, prototype field concrete mixtures were manufactured at a ready-mixed concrete plant. Afterward, a field construction demonstration was held to demonstrate the production and placement of structural-grade cold-weather-resistant concrete containing residual solids.

  19. Combustion of a Methane-Air Mixture in a Slot Burner with an Inert Insert in Mass Transfer to the Environment

    NASA Astrophysics Data System (ADS)

    Krainov, A. Yu.; Moiseeva, K. M.

    2016-03-01

    A problem on combustion of a methane-air mixture in a slot burner with an internal insert in mass transfer from the burner's exterior wall to the environment has been solved. A mathematical formulation of the problem takes account of the dependence of the diffusion, thermal-conductivity, and heat-transfer coefficients on temperature, and also of the heat removal from the gas to the environment by convective and radiant heat transfer. A numerical investigation has been carried out in a one-dimensional mathematical formulation of the problem in dimensional variables. The boundary of existence of a stable high-temperature regime of combustion of the methane-air mixture has been determined as a function of the rate of feed of the gas, the environmental temperature, and the width of the flow area of the burner.

  20. Chromatography-mass spectrometry studies on the metabolism of synthetic cannabinoids JWH-018 and JWH-073, psychoactive components of smoking mixtures.

    PubMed

    Grigoryev, Andrej; Savchuk, Sergey; Melnik, Aleksandra; Moskaleva, Natal'ja; Dzhurko, Jurij; Ershov, Mihail; Nosyrev, Aleksandr; Vedenin, Aleksandr; Izotov, Boris; Zabirova, Irina; Rozhanets, Vladimir

    2011-05-01

    The Russian Federation prohibited the distribution of herbal mixtures with synthetic aminoalkylindoles JWH-018 and JWH-073, agonist cannabinoid receptors, on January 22, 2010. The lack or low content of their native compounds in urine requires detailed identification of their metabolites, which are excreted with urine and are present in blood. Using gas and liquid chromatography-mass spectrometry, we identified a series of metabolites in urine samples from humans and rats that were products of the following reactions: (a) mono- and dihydroxylation of the parent compounds with hydroxyl groups located at aromatic and aliphatic residues, (b) carboxylation, (c) N-dealkylation and (d) N-dealkylation and hydroxylation. The prevailing urinary metabolites in humans are monohydroxylated forms, while N-dealkylated and N-dealkyl monohydroxylated forms are found in rats. Twenty-six samples of herbal smoking mixtures with JWH-018, purchased in Russia, were analysed.

  1. Application of ambient ionization high resolution mass spectrometry to determination of the botanical provenance of the constituents of psychoactive drug mixtures.

    PubMed

    Lesiak, Ashton D; Musah, Rabi A

    2016-09-01

    A continuing challenge in analytical chemistry is species-level determination of the constituents of mixtures that are made of a combination of plant species. There is an added urgency to identify components in botanical mixtures that have mind altering properties, due to the increasing global abuse of combinations of such plants. Here we demonstrate the proof of principle that ambient ionization mass spectrometry, namely direct analysis in real time-high resolution mass spectrometry (DART-HRMS), and statistical analysis tools can be used to rapidly determine the individual components within a psychoactive brew (Ayahuasca) made from a mixture of botanicals. Five plant species used in Ayahuasca preparations were subjected to DART-HRMS analysis. The chemical fingerprint of each was reproducible but unique, thus enabling discrimination between them. The presence of important biomarkers, including N,N-dimethyltryptamine, harmaline and harmine, was confirmed using in-source collision-induced dissociation (CID). Six Ayahuasca brews made from combinations of various plant species were shown to possess a high level of similarity, despite having been made from different constituents. Nevertheless, the application of principal component analysis (PCA) was useful in distinguishing between each of the brews based on the botanical species used in the preparations. From a training set based on 900 individual analyses, three principal components covered 86.38% of the variance, and the leave-one-out cross validation was 98.88%. This is the first report of ambient ionization MS being successfully used for determination of the individual components of plant mixtures. PMID:27348465

  2. AB INITIO EQUATION OF STATE FOR HYDROGEN-HELIUM MIXTURES WITH RECALIBRATION OF THE GIANT-PLANET MASS-RADIUS RELATION

    SciTech Connect

    Militzer, B.; Hubbard, W. B.

    2013-09-10

    Using density functional molecular dynamics simulations, we determine the equation of state (EOS) for hydrogen-helium mixtures spanning density-temperature conditions typical of giant-planet interiors, {approx}0.2-9 g cm{sup -3} and 1000-80,000 K for a typical helium mass fraction of 0.245. In addition to computing internal energy and pressure, we determine the entropy using an ab initio thermodynamic integration technique. A comprehensive EOS table with 391 density-temperature points is constructed and the results are presented in the form of a two-dimensional free energy fit for interpolation. Deviations between our ab initio EOS and the semi-analytical EOS model by Saumon and Chabrier are analyzed in detail, and we use the results for initial revision of the inferred thermal state of giant planets with known values for mass and radius. Changes are most pronounced for planets in the Jupiter mass range and below. We present a revision to the mass-radius relationship that makes the hottest exoplanets increase in radius by {approx}0.2 Jupiter radii at fixed entropy and for masses greater than {approx}0.5 Jupiter mass. This change is large enough to have possible implications for some discrepant ''inflated giant exoplanets''.

  3. UV-Vis, infrared, and mass spectroscopy of electron irradiated frozen oxygen and carbon dioxide mixtures with water

    SciTech Connect

    Jones, Brant M.; Kaiser, Ralf I.; Strazzulla, Giovanni

    2014-02-01

    Ozone has been detected on the surface of Ganymede via observation of the Hartley band through the use of ultraviolet spectroscopy and is largely agreed upon to be formed by radiolytic processing via interaction of magnetospheric energetic ions and/or electrons with oxygen-bearing ices on Ganymede's surface. Interestingly, a clearly distinct band near 300 nm within the shoulder of the UV-Vis spectrum of Ganymede was also observed, but currently lacks an acceptable physical or chemical explanation. Consequently, the primary motivation behind this work was the collection of UV-Vis absorption spectroscopy of ozone formation by energetic electron bombardment of a variety of oxygen-bearing ices (oxygen, carbon dioxide, water) relevant to this moon as well as other solar system. Ozone was indeed synthesized in pure ices of molecular oxygen, carbon dioxide and a mixture of water and oxygen, in agreement with previous studies. The Hartley band of the ozone synthesized in these ice mixtures was observed in the UV-Vis spectra and compared with the spectrum of Ganymede. In addition, a solid state ozone absorption cross section of 6.0 ± 0.6 × 10{sup –17} cm{sup 2} molecule{sup –1} was obtained from the UV-Vis spectral data. Ozone was not produced in the irradiated carbon dioxide-water mixtures; however, a spectrally 'red' UV continuum is observed and appears to reproduce well what is observed in a large number of icy moons such as Europa.

  4. Uv-Vis, Infrared, and Mass Spectroscopy of Electron Irradiated Frozen Oxygen and Carbon Dioxide Mixtures with Water

    NASA Astrophysics Data System (ADS)

    Jones, Brant M.; Kaiser, Ralf I.; Strazzulla, Giovanni

    2014-02-01

    Ozone has been detected on the surface of Ganymede via observation of the Hartley band through the use of ultraviolet spectroscopy and is largely agreed upon to be formed by radiolytic processing via interaction of magnetospheric energetic ions and/or electrons with oxygen-bearing ices on Ganymede's surface. Interestingly, a clearly distinct band near 300 nm within the shoulder of the UV-Vis spectrum of Ganymede was also observed, but currently lacks an acceptable physical or chemical explanation. Consequently, the primary motivation behind this work was the collection of UV-Vis absorption spectroscopy of ozone formation by energetic electron bombardment of a variety of oxygen-bearing ices (oxygen, carbon dioxide, water) relevant to this moon as well as other solar system. Ozone was indeed synthesized in pure ices of molecular oxygen, carbon dioxide and a mixture of water and oxygen, in agreement with previous studies. The Hartley band of the ozone synthesized in these ice mixtures was observed in the UV-Vis spectra and compared with the spectrum of Ganymede. In addition, a solid state ozone absorption cross section of 6.0 ± 0.6 × 10-17 cm2 molecule-1 was obtained from the UV-Vis spectral data. Ozone was not produced in the irradiated carbon dioxide-water mixtures; however, a spectrally "red" UV continuum is observed and appears to reproduce well what is observed in a large number of icy moons such as Europa.

  5. NMR/MS Translator for the Enhanced Simultaneous Analysis of Metabolomics Mixtures by NMR Spectroscopy and Mass Spectrometry: Application to Human Urine.

    PubMed

    Bingol, Kerem; Brüschweiler, Rafael

    2015-06-01

    A novel metabolite identification strategy is presented for the combined NMR/MS analysis of complex metabolite mixtures. The approach first identifies metabolite candidates from 1D or 2D NMR spectra by NMR database query, which is followed by the determination of the masses (m/z) of their possible ions, adducts, fragments, and characteristic isotope distributions. The expected m/z ratios are then compared with the MS(1) spectrum for the direct assignment of those signals of the mass spectrum that contain information about the same metabolites as the NMR spectra. In this way, the mass spectrum can be assigned with very high confidence, and it provides at the same time validation of the NMR-derived metabolites. The method was first demonstrated on a model mixture, and it was then applied to human urine collected from a pool of healthy individuals. A number of metabolites could be detected that had not been reported previously, further extending the list of known urine metabolites. The new analysis approach, which is termed NMR/MS Translator, is fully automated and takes only a few seconds on a computer workstation. NMR/MS Translator synergistically uses the power of NMR and MS, enhancing the accuracy and efficiency of the identification of those metabolites compiled in databases. PMID:25881480

  6. Letter: Fast detection of polycyclic aromatic hydrocarbons in complex mixtures of organic compounds based on gas chromatography-mass spectrometry with atmospheric pressure photoionization.

    PubMed

    Revelsky, Igor A; Tikhonova, I N; Yashin, Yu S

    2015-01-01

    The research is devoted to the investigation of the selectivity detection of 16 polycyclic aromatic hydrocarbons (PAHs) using gas chromatography-mass spectrometry (GC-MS), electron ionization (EI) GC-MS with atmospheric pressure photoionization (APPhI) and GC-MS atmospheric pressure photochemical ionization (APPhCI) when vapors of different substances (benzene, toluene, and naphthalene) were used as gas reagents. Capillary columns of different lengths were used for the separation of the components of the mixture of 44 semivolatile organic compounds. It was shown that the most-selective detection of 16 PAHs in a 44- component mixture was possible when GC-MS APPhCI was used. Only 16 PAHs were registered on the respective mass chromatograms and a fast detection of them was possible. The respective APPhI and APPhCI mass spectra consisted of only peak of the respective molecular ion, M⁺⁺ - the radical cation. Detection limits were 3 pg μL⁻¹ to 15 pg μL. PMID:26579932

  7. Investigation of mass dependence effects for the accurate determination of molybdenum isotope amount ratios by MC-ICP-MS using synthetic isotope mixtures.

    PubMed

    Malinovsky, Dmitry; Dunn, Philip J H; Petrov, Panayot; Goenaga-Infante, Heidi

    2015-01-01

    Methodology for absolute Mo isotope amount ratio measurements by multicollector inductively coupled plasma-mass spectrometry (MC-ICP-MS) using calibration with synthetic isotope mixtures (SIMs) is presented. For the first time, synthetic isotope mixtures prepared from seven commercially available isotopically enriched molybdenum metal powders ((92)Mo, (94)Mo, (95)Mo, (96)Mo, (97)Mo, (98)Mo, and (100)Mo) are used to investigate whether instrumental mass discrimination of Mo isotopes in MC-ICP-MS is consistent with mass-dependent isotope distribution. The parent materials were dissolved and mixed as solutions to obtain mixtures with accurately known isotope amount ratios. The level of elemental impurities in the isotopically enriched molybdenum metal powders was quantified by ICP-MS by using both high-resolution and reaction cell instruments to completely resolve spectral interferences. The Mo isotope amount ratio values with expanded uncertainty (k = 2), determined by MC-ICP-MS for a high-purity Mo rod from Johnson Matthey, were as follows: (92)Mo/(95)Mo = 0.9235(9), (94)Mo/(95)Mo = 0.5785(8), (96)Mo/(95)Mo = 1.0503(9), (97)Mo/(95)Mo = 0.6033(6), (98)Mo/(95)Mo = 1.5291(20), and (100)Mo/(95)Mo = 0.6130(7). A full uncertainty budget for the measurements is presented which shows that the largest contribution to the uncertainty budget comes from correction for elemental impurities (∼51%), followed by the contribution from weighing operations (∼26 %). The atomic weight of molybdenum was calculated to be 95.947(2); the uncertainty in parentheses is expanded uncertainty with the coverage factor of 2. A particular advantage of the developed method is that calibration factors for all six Mo isotope amount ratios, involving the (95)Mo isotope, were experimentally determined. This allows avoiding any assumption on mass-dependent isotope fractions in MC-ICP-MS, inherent to the method of double spike previously used for Mo isotope amount ratio

  8. Transport properties of self-consolidating concrete

    SciTech Connect

    Sonebi, M.; Nanukuttan, S.

    2009-03-15

    This study reports the findings from an investigation carried out to study the effect of the mixture variations on the durability of medium- and high-strength self-consolidating concrete (SCC). The mixture variations studied include the type of mineral admixtures, such as limestone powder (LSP) and pulverized fuel ash (PFA), and viscosity-modifying admixtures (VMA) for both medium- and high-strength SCC. Air permeability, water permeability, capillary absorption, and chloride diffusivity were used to assess the durability of SCC mixtures in comparison with normal, vibrated concretes. The results showed that SCC mixtures, for medium- and high-strength grades using PFA followed by LSP give lower permeability, properties compared with normal concretes. SCC made with VMA had a higher sorptivity, air permeability, and water permeability compared with other SCC mixtures, which can be attributed to higher water-cement ratio (w/c) and lack of pore filling effect. An in-place migration coefficient was obtained using the in-place ion migration test. This was used to compare the potential diffusivity of different concretes. The results indicated that SCC, for both grades of strength, made with PFA showed much lower diffusivity values in comparison with other mixtures, whereas the SCC mixtures with VMA showed higher diffusivity.

  9. Effect of Non-Condensable Gas Mass Fraction on Condensation Heat Transfer for Water-Ethanol Vapor Mixture

    NASA Astrophysics Data System (ADS)

    Wang, Shixue; Utaka, Yoshio

    The condensation heat transfer characteristic curves for a ternary vapor mixture of water, ethanol and air (or nitrogen) under several ethanol concentrations and relatively low concentrations of air (or nitrogen) were measured. The effect of non-condensable gas on several different domains in the condensation curves was discussed. The effect of non-condensable gas in the domains controlled by the diffusion resistance and the filmwise condensation was not notable; whereas that in the domain dominated by the condensate resistance of dropwise mode was remarkable. Moreover, variations due to changes in non-condensable gas concentration of several characteristic points representing the curves were discussed.

  10. Heat and mass transfer in fluidized-bed furnaces in combustion of a coal-water mixture

    NASA Astrophysics Data System (ADS)

    Berg, B. V.; Bogatova, T. F.

    1996-11-01

    The possibility in principle of burning highly ballasted fuel, including irrigated fuel, is considered. The permissible limits of the ash content and the moisture content are determined. The process of the thermal interaction between a drop of a coal-water mixture (CWM) and a fluidized bed is analyzed. Calculations of the distribution of volatiles and moisture in the fluidized bed in one-sided introduction of CWM are performed. The combustion of a CWM in a boiler furnace confirmed the practical possibility and expediency of recovering irrigated fuel waste of coal cleaning by this method.

  11. Diffusion of Radionuclides in Concrete and Soil

    SciTech Connect

    Mattigod, Shas V.; Wellman, Dawn M.; Bovaird, Chase C.; Parker, Kent E.; Recknagle, Kurtis P.; Clayton, Libby N.; Wood, Marcus I.

    2012-04-25

    One of the methods being considered for safely disposing of Category 3 low-level radioactive wastes is to encase the waste in concrete. Such concrete encasement would contain and isolate the waste packages from the hydrologic environment and would act as an intrusion barrier. Any failure of concrete encasement may result in water intrusion and consequent mobilization of radionuclides from the waste packages. The mobilized radionuclides may escape from the encased concrete by mass flow and/or diffusion and move into the surrounding subsurface environment. Therefore, it is necessary to assess the performance of the concrete encasement structure and the ability of the surrounding soil to retard radionuclide migration. The objective of our study was to measure the diffusivity of Re, Tc and I in concrete containment and the surrounding vadose zone soil. Effects of carbonation, presence of metallic iron, and fracturing of concrete and the varying moisture contents in soil on the diffusivities of Tc and I were evaluated.

  12. Material and Flexural Properties of Fiber-reinforced Rubber Concrete

    NASA Astrophysics Data System (ADS)

    Helminger, Nicholas P.

    The purpose of this research is to determine the material properties of rubber concrete with the addition of fibers, and to determine optimal mixture dosages of rubber and fiber in concrete for structural applications. Fiber-reinforced concrete and rubberized concrete have been researched separately extensively, but this research intends to combine both rubber and fiber in a concrete matrix in order to create a composite material, fiber-reinforced rubber concrete (FRRC). Sustainability has long been important in engineering design, but much of the previous research performed on sustainable concrete does not result in a material that can be used for practical purposes. While still achieving a material that can be used for structural applications, economical considerations were given when choosing the proportions and types of constituents in the concrete mix. Concrete mixtures were designed, placed, and tested in accordance with common procedures and standards, with an emphasis on practicality. Properties that were investigated include compressive strength, tensile strength, modulus of elasticity, toughness, and ductility. The basis for determining the optimal concrete mixture is one that is economical, practical, and exhibits ductile properties with a significant strength. Results show that increasing percentages of rubber tend to decrease workability, unit weight, compressive strength, split tensile strength, and modulus of elasticity while the toughness is increased. The addition of steel needle fibers to rubber concrete increases unit weight, compressive strength, split tensile strength, modulus of elasticity, toughness, and ductility of the composite material.

  13. Laser ablation of concrete.

    SciTech Connect

    Savina, M.

    1998-10-05

    Laser ablation is effective both as an analytical tool and as a means of removing surface coatings. The elemental composition of surfaces can be determined by either mass spectrometry or atomic emission spectroscopy of the atomized effluent. Paint can be removed from aircraft without damage to the underlying aluminum substrate, and environmentally damaged buildings and sculptures can be restored by ablating away deposited grime. A recent application of laser ablation is the removal of radioactive contaminants from the surface and near-surface regions of concrete. We present the results of ablation tests on concrete samples using a high power pulsed Nd:YAG laser with fiber optic beam delivery. The laser-surface interaction was studied on various model systems consisting of Type I Portland cement with varying amounts of either fine silica or sand in an effort to understand the effect of substrate composition on ablation rates and mechanisms. A sample of non-contaminated concrete from a nuclear power plant was also studied. In addition, cement and concrete samples were doped with non-radioactive isotopes of elements representative of cooling waterspills, such as cesium and strontium, and analyzed by laser-resorption mass spectrometry to determine the contamination pathways. These samples were also ablated at high power to determine the efficiency with which surface contaminants are removed and captured. The results show that the neat cement matrix melts and vaporizes when little or no sand or aggregate is present. Surface flows of liquid material are readily apparent on the ablated surface and the captured aerosol takes the form of glassy beads up to a few tens of microns in diameter. The presence of sand and aggregate particles causes the material to disaggregate on ablation, with intact particles on the millimeter size scale leaving the surface. Laser resorption mass spectrometric analysis showed that cesium and potassium have similar chemical environments in the

  14. Evaluation of properties of recycled asphalt concrete hot mix

    SciTech Connect

    Brown, E.R.

    1983-01-01

    This study was undertaken to evaluate the laboratory performance of recycled asphalt concrete mixtures and to compare these results to those measured for conventional asphalt concrete mixtures. To make these comparisons, samples of aged asphalt concrete were obtained from three locations where recycling was planned. These samples were blended with new aggregate and new asphalt materials to produce six different recycled mixtures. Two aggregate types, a crushed gravel and a crushed limestone, were used to produce two conventional mixtures and to blend with the reclaimed asphalt pavement to produce the six recycled mixtures. Three asphalt materials which were obtained to produce the various mixtures being evaluated consisted of AC-20 for preparing the conventional mixtures and AC-5 and a recycling agent for preparing the recycled mixtures. The Shell BISAR computer program was used to predict the stesses and strains for two typical pavement sections under a given loading conditions. The computed stresses and strains were then analyzed along with the laboratory fatigue tests to predict the fatigue performance of the various mixtures. The results of this study indicated a satisfactory comparison between laboratory performance of recycled mixtures and conventional mixtures. Fatigue analysis indicated that the conventional mixtures would provide the greatest fatigue resistance in thick asphalt concrete layers at lower temperatures while the recycled mixtures would provide the greatest fatigue resistance in thin asphalt layers at higher temperatures.

  15. Radiation resistant concrete for applications in nuclear power and radioactive waste industries

    NASA Astrophysics Data System (ADS)

    Burnham, Steven Robert

    Elemental components of ordinary concrete contain a variety of metals and rare earth elements that are susceptible to neutron activation. This activation occurs by means of radiative capture, a neutron interaction that results in formation of radioisotopes such as Co-60, Eu-152, and Eu-154. Studies have shown that these three radioisotopes are responsible for the residual radioactivity found in nuclear power plant concrete reactor dome and shielding walls. Such concrete is classified as Low Level Radioactive Waste (LLRW) and Very Low Level Waste (VLLW) by International Atomic Energy Agency (IAEA) standards and requires disposal at appropriate disposal sites. There are only three such sites in the USA, and every nuclear power plant will produce at the time of decommissioning approximately 1,500 tonnes of activated concrete classified as LLRW and VLLW. NAVA ALIGA (ancient word for a new stone) is a new concrete mixture developed mainly by research as presented in this thesis. The purpose of NAVA ALIGA is to satisfy IAEA clearance levels if used as a material for reactor dome, spent fuel pool, or radioactive waste canisters. NAVA ALIGA will never be activated above the IAEA clearance level after long-term exposure to neutron radiation when used as a material for reactor dome, spent fuel pool, and radioactive waste canisters. Components of NAVA ALIGA were identified using Instrumental Neutron Activation Analysis (INAA) and Inductively Coupled Plasma Mass Spectrometry (ISP-MS) to determine trace element composition. In addition, it was tested for compressive strength and permeability, important for nuclear infrastructure. The studied mixture had a high water to cement ratio of 0.56, which likely resulted in the high measured permeability, yet the mixture also showed a compressive strength greater than 6 000 psi after 28 days. In addition to this experimental analysis, which goal was to develop a standard approach to define the concrete mixtures in satisfying the IAEA

  16. Mass spectrometric investigation of the ionic species in a dielectric barrier discharge operating in helium-water vapour mixtures

    NASA Astrophysics Data System (ADS)

    Abd-Allah, Z.; Sawtell, D. A. G.; McKay, K.; West, G. T.; Kelly, P. J.; Bradley, J. W.

    2015-03-01

    Using advanced mass spectrometry the chemistry of ionic species present in an atmospheric-pressure parallel plate dielectric barrier discharge (DBD) with a single dielectric on the powered electrode have been identified. The discharge was driven in helium with controllable concentrations of water vapour using an excitation frequency of 10 kHz and an applied voltage of 1.2 kV. Both negative and positive ions were identified and their relative intensity determined with variation of water concentration in the discharge, inter-electrode spacing, gas residence time and nominal applied power. The most abundant negative ions were of the family \\text{O}{{\\text{H}}-}{{≤ft({{\\text{H}}2}\\text{O}\\right)}n} , while the positive ions were dominated by those of the form {{{H}}^ + }{{{(}}{{{H}}_2}{{O)}}_n} , with n up to 9 in both cases. Negative and positive ions responded in a similar way to changes in the operating parameters, with the particular response depending on the ion mass. Increasing the inter-electrode spacing and the water concentration in the discharge led to an increase in the intensity of large mass ionic water clusters. However, increasing the residence time of the species in the plasma region and increasing the applied power resulted in fragmentation of large water clusters to produce smaller ions.

  17. Elucidation of high micro-heterogeneity of an acidic-neutral trichotoxin mixture from Trichoderma harzianum by electrospray ionization quadrupole time-of-flight mass spectrometry.

    PubMed

    Suwan, S; Isobe, M; Kanokmedhakul, S; Lourit, N; Kanokmedhakul, K; Soytong, K; Koga, K

    2000-12-01

    The high micro-heterogeneity of an acidic-neutral trichotoxin mixture from T. harzianum, PC01, was elucidated using a modern tandem mass spectrometer equipped with an electrospray ionization source, a hybrid quadrupole-orthogonal accelerator and a reflectron time-of-flight analyzer. The trichotoxins appeared predominantly in six possible doubly charged pseudo molecular ions with three different adducts (H, Na and K) as [M + 2H](2+), [M + H + Na](2+), [M + H + K](2+), [M + 2Na](2+), [M + Na + K](2+) and [M + 2K](2+). The singly charged pseudomolecular ions, [M + H](+), [M + Na](+) and [M + K](+), occurred only in low abundance when the cone voltages were higher than 30 V. Additional singly charged fragments, b(12) and y"6 (complementary N- and C-terminal fragments), were obtained in high abundance using high cone voltages. The peak patterns of both singly and doubly charged molecular adducts revealed that this trichotoxin mixture contained several components having 6-7 molecular masses with a consecutive 14 u difference among members in the same molecular adduct series. Furthermore, well resolved isotopic peaks of every doubly or singly charged ions and their reproducible peak intensity allowed the identification of the mixing of acidic trichotoxins 1 u molecular mass heavier than the neutral counterparts in the sample. Tandem mass spectrometric (MS/MS) analyses of various singly charged b(12) and y"6 ions supported the sequence deduction of the major and minor components and also the position of Glu in the sequences of these acidic molecules. The setting of either low or high resolution of the quadrupole mass filter unit together with a suitable variation of the collision voltage for any MS/MS precursor were the tools for extracting a number of mixed components and obtaining the major and minor sequences of these precursor peaks. The nature of the MS/MS fragmentation and the data assignment of three major doubly charged ions, [M + 2H](2+), [M + K + H](2+) and [M

  18. Estimating crack growth in temperature damaged concrete

    NASA Astrophysics Data System (ADS)

    Recalde, Juan Jose

    2009-12-01

    Evaluation of the structural condition of deteriorated concrete infrastructure and evaluation of new sustainable cementitious materials require an understanding of how the material will respond to applied loads and environmental exposures. A fundamental understanding of how microstructural changes in these materials relate to changes in mechanical properties and changes in fluid penetrability is needed. The ability to provide rapid, inexpensive assessment of material characteristics and relevant engineering properties is valuable for decision making and asset management purposes. In this investigation, the effects of changes in dynamic elastic properties with water content and fluid penetrability properties before and after a 300°C exposure were investigated based on estimates of the crack density parameter from dry and saturated cracked media. The experimental and analytical techniques described in this dissertation allow calculation of a value for the crack density parameter using nondestructive determination of wet and dry dynamic shear modulus of relatively thin disks. The techniques were used to compare a conventional concrete mixture to several mixtures with enhanced sustainability characteristics. The three enhanced sustainable materials investigated were a very high fly ash mixture, a magnesium phosphate cement based mortar, and a magnesium phosphate cement based concrete, and were compared to a conventional concrete mixture. The analysis provided both quantitative assessment of changes with high temperature damage and autogenous healing, and estimates of changes in mean crack trace lengths. The results showed that water interaction, deterioration due to damage, and autogenous healing recovery were different for the magnesium phosphate cement based mixtures than the portland cement based concrete mixtures. A strong correlation was found between log-transformed Air Permeability Index, dynamic shear modulus, and crack density parameter. The findings imply

  19. FAST TRACK COMMUNICATION: Mass spectrometry study of positive and negative ions in a capacitively coupled atmospheric pressure RF excited glow discharge in He-water mixtures

    NASA Astrophysics Data System (ADS)

    Bruggeman, Peter; Iza, Felipe; Lauwers, Daniël; Aranda Gonzalvo, Yolanda

    2010-01-01

    In this contribution RF excited atmospheric pressure glow discharges are investigated in He-water mixtures in a parallel metal plate reactor by mass spectrometry. Positive and negative ion fluxes to the electrode are investigated as a function of varying water concentration and discharge power. The dominant positive ions are H3O+ (and its clusters), OH+, O+, O_2^+ , He_2^+ , HeH+, O_2^+ and H_3^+ . Negative ions are detectable from a concentration of 900 ppm water in He onwards. Coinciding with the emergence of the negative ions, there is a drop in positive ion flux to the mass spectrometer and a significant increase in applied voltage indicating increasing electron loss by attachment and ion loss by mutual (three and two body) positive-negative ion recombination. The dominant negative ions are OH- and its clusters. The negative ion flux increases with increasing water concentration. Positive and negative ion cluster formation increases with decreasing discharge power and increasing concentration of water vapour at constant power. It is shown that the size of the sampling orifice of the inlet of the mass spectrometer is important for sampling atmospheric pressure active plasmas due to the presence of the narrow sheath.

  20. Characterization of a mixture of lobster digestive cysteine proteinases by ionspray mass spectrometry and tryptic mapping with LC--MS and LC--MS--MS

    NASA Astrophysics Data System (ADS)

    Thibault, P.; Pleasance, S.; Laycock, M. V.; Mackay, R. M.; Boyd, R. K.

    1991-12-01

    An inseparable mixture of two cysteine proteinases, isolated from the digestive tract of the American lobster, was investigated by ionspray mass spectrometry (ISP-MS), using a combination of infusion of intact proteins with on-line liquid chromatography--mass spectrometry (LC--MS) and LC--MS--MS analyses of tryptic digests. These data were interpreted by comparisons with predictions from results of molecular cloning of cysteine-proteinase-encoding messenger RNA sequences previously isolated from the lobster hepatopancreas. Investigations of the numbers of free thiol groups and of disulfide bonds were made by measuring the molecular weights of the alkylated proteins with and without prior reduction of disulfide bonds, and comparison with the corresponding data for the native proteins. Identification of tyrptic fragment peptides containing cysteine residues was facilitated by comparing LC--MS analyses of tryptic digests of denatured and of denatured and alkylated proteins, since such tryptic peptides are subject to shifts in both mass and retention time upon reduction and alkylation. Confirmation of amino acid sequences was obtained from fragment ion spectra of each tryptic peptide (alkylated or not) as it eluted from the column. Acquisition of such on-line LC--MS data was possible through use of the entire effluent from a standard 1 mm high performance liquid chromatography (HPLC) column by an IonsSpray® LC--MS interface (pneumatically assisted electrospray).

  1. Determination of ion mobility collision cross sections for unresolved isomeric mixtures using tandem mass spectrometry and chemometric deconvolution.

    PubMed

    Harper, Brett; Neumann, Elizabeth K; Stow, Sarah M; May, Jody C; McLean, John A; Solouki, Touradj

    2016-10-01

    Ion mobility (IM) is an important analytical technique for determining ion collision cross section (CCS) values in the gas-phase and gaining insight into molecular structures and conformations. However, limited instrument resolving powers for IM may restrict adequate characterization of conformationally similar ions, such as structural isomers, and reduce the accuracy of IM-based CCS calculations. Recently, we introduced an automated technique for extracting "pure" IM and collision-induced dissociation (CID) mass spectra of IM overlapping species using chemometric deconvolution of post-IM/CID mass spectrometry (MS) data [J. Am. Soc. Mass Spectrom., 2014, 25, 1810-1819]. Here we extend those capabilities to demonstrate how extracted IM profiles can be used to calculate accurate CCS values of peptide isomer ions which are not fully resolved by IM. We show that CCS values obtained from deconvoluted IM spectra match with CCS values measured from the individually analyzed corresponding peptides on uniform field IM instrumentation. We introduce an approach that utilizes experimentally determined IM arrival time (AT) "shift factors" to compensate for ion acceleration variations during post-IM/CID and significantly improve the accuracy of the calculated CCS values. Also, we discuss details of this IM deconvolution approach and compare empirical CCS values from traveling wave (TW)IM-MS and drift tube (DT)IM-MS with theoretically calculated CCS values using the projected superposition approximation (PSA). For example, experimentally measured deconvoluted TWIM-MS mean CCS values for doubly-protonated RYGGFM, RMFGYG, MFRYGG, and FRMYGG peptide isomers were 288.8 Å(2), 295.1 Å(2), 296.8 Å(2), and 300.1 Å(2); all four of these CCS values were within 1.5% of independently measured DTIM-MS values.

  2. Determination of ion mobility collision cross sections for unresolved isomeric mixtures using tandem mass spectrometry and chemometric deconvolution.

    PubMed

    Harper, Brett; Neumann, Elizabeth K; Stow, Sarah M; May, Jody C; McLean, John A; Solouki, Touradj

    2016-10-01

    Ion mobility (IM) is an important analytical technique for determining ion collision cross section (CCS) values in the gas-phase and gaining insight into molecular structures and conformations. However, limited instrument resolving powers for IM may restrict adequate characterization of conformationally similar ions, such as structural isomers, and reduce the accuracy of IM-based CCS calculations. Recently, we introduced an automated technique for extracting "pure" IM and collision-induced dissociation (CID) mass spectra of IM overlapping species using chemometric deconvolution of post-IM/CID mass spectrometry (MS) data [J. Am. Soc. Mass Spectrom., 2014, 25, 1810-1819]. Here we extend those capabilities to demonstrate how extracted IM profiles can be used to calculate accurate CCS values of peptide isomer ions which are not fully resolved by IM. We show that CCS values obtained from deconvoluted IM spectra match with CCS values measured from the individually analyzed corresponding peptides on uniform field IM instrumentation. We introduce an approach that utilizes experimentally determined IM arrival time (AT) "shift factors" to compensate for ion acceleration variations during post-IM/CID and significantly improve the accuracy of the calculated CCS values. Also, we discuss details of this IM deconvolution approach and compare empirical CCS values from traveling wave (TW)IM-MS and drift tube (DT)IM-MS with theoretically calculated CCS values using the projected superposition approximation (PSA). For example, experimentally measured deconvoluted TWIM-MS mean CCS values for doubly-protonated RYGGFM, RMFGYG, MFRYGG, and FRMYGG peptide isomers were 288.8 Å(2), 295.1 Å(2), 296.8 Å(2), and 300.1 Å(2); all four of these CCS values were within 1.5% of independently measured DTIM-MS values. PMID:27639144

  3. Mass Flux Stability in the Presence of Temperature Excursions and Perturbations in Solid ^3He-^4He Mixtures

    NASA Astrophysics Data System (ADS)

    Vekhov, Ye.; Hallock, R. B.

    2016-11-01

    The DC superfluid ^4He mass flux through a cell filled with solid ^4He diluted by ppm amounts of ^3He is susceptible to flux changes when perturbations of the solid sample are imposed. We report on the details of the reproducibility of the flux following excursions in temperature and cryostat helium transfer-induced apparatus vibration, particularly including excursions to temperatures above which the flux is immeasurably small. And we report on behavior following an annealing, partial melting, and re-freezing of the sample at temperatures and pressures close to and on the melting curve.

  4. Differential mass spectrometry: a label-free LC-MS method for finding significant differences in complex peptide and protein mixtures.

    PubMed

    Wiener, Matthew C; Sachs, Jeffrey R; Deyanova, Ekaterina G; Yates, Nathan A

    2004-10-15

    Efficiently identifying and quantifying disease- or treatment-related changes in the abundance of proteins is an important area of research for the pharmaceutical industry. Here we describe an automated, label-free method for finding differences in complex mixtures using complete LC-MS data sets, rather than subsets of extracted peaks or features. The method selectively finds statistically significant differences in the intensity of both high-abundance and low-abundance ions, accounting for the variability of measured intensities and the fact that true differences will persist in time. The method was used to compare two complex peptide mixtures with known peptide differences. This controlled experiment allowed us to assess the validity of each difference found and so to analyze the method's sensitivity and specificity. The method detects both presence versus absence and a 2-fold change in peptide concentration near the limit of detection of the instrument used, where chromatographic peaks may not be sufficiently well defined to be detected in individual samples. The method is more sensitive and gives fewer false positives than subtractive methods that ignore signal variability. Differential mass spectrometry combined with targeted MS/MS analysis of only identified differences may save both computation time and human effort compared to shotgun proteomics approaches. PMID:15481957

  5. Evaluation of molecular mass and tacticity of polyvinyl alcohol by non-equilibrium capillary electrophoresis of equilibrium mixtures of a polymer and a dye.

    PubMed

    Carrasco-Correa, Enrique Javier; Beneito-Cambra, Miriam; Herrero-Martínez, José Manuel; Ramis-Ramos, Guillermo

    2011-04-22

    Non-equilibrium capillary electrophoresis of equilibrium mixtures (NECEEM) has been used to characterize polyvinyl alcohol (PVA). Commercial PVA samples with different molecular masses, from M(w)=15 up to 205 kDa, were used. According to the (13)C NMR spectra, the samples also differed in tacticity (stereoregularity). Mixtures of PVA and the anionic azo-dye Congo Red (CR) were injected in the presence of a borate buffer. The electropherograms gave a band and a peak due to the residual PVA-CR complex and the excess dye, respectively, plus a superimposed exponential decay due to the partial dissociation of the complex during migration. The stoichiometry of the PVA-CR complex, q=[monomer]/[dye], reached a maximum, q(sat), which depended on both M(w) and tacticity of PVA. Thus, q(sat) decreased from a molar ratio of ca. 4.9 to 3.6 at increasing M(w) values, this variation also being largely dependent on tacticity. A similar dependence of the electrophoretic mobility of the complex on both M(w) and tacticity was also observed. A possible explanation, based on the formation of a stack of CR ions inside the PVA-CR complex, was proposed and discussed. Finally, at increasing M(w) values, the stability constant of the complex increased slightly, and the pseudo-first order dissociation rate of the complex decreased, this later parameter also showing a dependence on both M(w) and tacticity.

  6. Simultaneous quantification of Aroclor mixtures in soil samples by gas chromatography/mass spectrometry with solid phase microextraction using partial least-squares regression.

    PubMed

    Zhang, Mengliang; Harrington, Peter de B

    2015-01-01

    Multivariate partial least-squares (PLS) method was applied to the quantification of two complex polychlorinated biphenyls (PCBs) commercial mixtures, Aroclor 1254 and 1260, in a soil matrix. PCBs in soil samples were extracted by headspace solid phase microextraction (SPME) and determined by gas chromatography/mass spectrometry (GC/MS). Decachlorinated biphenyl (deca-CB) was used as internal standard. After the baseline correction was applied, four data representations including extracted ion chromatograms (EIC) for Aroclor 1254, EIC for Aroclor 1260, EIC for both Aroclors and two-way data sets were constructed for PLS-1 and PLS-2 calibrations and evaluated with respect to quantitative prediction accuracy. The PLS model was optimized with respect to the number of latent variables using cross validation of the calibration data set. The validation of the method was performed with certified soil samples and real field soil samples and the predicted concentrations for both Aroclors using EIC data sets agreed with the certified values. The linear range of the method was from 10μgkg(-1) to 1000μgkg(-1) for both Aroclor 1254 and 1260 in soil matrices and the detection limit was 4μgkg(-1) for Aroclor 1254 and 6μgkg(-1) for Aroclor 1260. This holistic approach for the determination of mixtures of complex samples has broad application to environmental forensics and modeling.

  7. Study of the phase I and phase II metabolism of a mixture containing multiple tanshinones using liquid chromatography/tandem mass spectrometry.

    PubMed

    Liu, Jie; Wu, Jianlin; Wang, Xiaoru; Cai, Zongwei

    2007-01-01

    Metabolism of a mixture containing four dominant components in lipid solubles of Danshen was studied both in vitro and in vivo. The parent compounds and their metabolites were simultaneously detected by using liquid chromatography coupled with ion trap mass spectrometry. The results indicated that oxidation was the major pathway in phase I metabolism. O-Glucuronidation of the hydroxylated tanshinones was identified in the rat urine samples collected after the oral administration of the tanshinone components. The metabolic rates obtained from the in vitro metabolism study of each individual component were significantly different from those obtained from the incubation study of the four components in a cassette. Metabolite identification showed that tanshinone IIA and tanshinone I were the major metabolites of cryptotanshinone and dihydrotanshinone I, respectively. The obtained results demonstrated the metabolic change between the active components in Danshen and suggested the need to study the multiple components or even the extract from the herbal medicines. PMID:17694593

  8. Preliminary studies on identification of inorganic species in complex mixtures by electrospray mass spectrometry in the counter ion mode

    SciTech Connect

    Mollah, Sahana

    1999-11-08

    Suppression of mass spectral peaks due to matrix problem is a major hurdle to overcome during identification work. So far, preliminary studies have been done in investigating solutions containing various percentages of nitric and hydrochloric acid. Since other anions would also be present in real samples, also needed to be examined is how the extent of suppression of metal complexes by Cl{sup {minus}} compares with suppression by other anions such as PO{sub 4}{sup 3{minus}} or SO{sub 4}{sup 2{minus}}. If suppression of other anions is as severe as that of the chloride ion, then it would be virtually impossible to analyze unknown samples containing large amount of such anions by direct infusion electrospray mass spectrometry. It seems like a separation step is needed to separate these matrix anions from the metal complexes prior to putting the solution through the electrospray. However, separation of inorganic complexes can be difficult and has not been studied thoroughly as LC separation of bioorganic compounds. Both zinc and copper chloro complexes have been observed to be more tolerant to higher amount of chloride ion present in a solution compared to the group I and II metal chloro complexes. Other transition metals including the lanthanide complexes need to be examined more intensively to see how they fare against other transition metal complexes. So far, only preliminary work has been done in identifying inorganic species in solutions using both ICP-MS and ES-MS. The solution contained a number of metals but only one major anion, NO{sub 3}{sup {minus}}. Therefore, complex solutions containing a number of anions and metals can be examined to see if identification is still feasible. This identification work can be continued on into investigating real samples.

  9. Compressive strength of concrete and mortar containing fly ash

    DOEpatents

    Liskowitz, John W.; Wecharatana, Methi; Jaturapitakkul, Chai; Cerkanowicz, deceased, Anthony E.

    1997-01-01

    The present invention relates to concrete, mortar and other hardenable mixtures comprising cement and fly ash for use in construction. The invention includes a method for predicting the compressive strength of such a hardenable mixture, which is very important for planning a project. The invention also relates to hardenable mixtures comprising cement and fly ash which can achieve greater compressive strength than hardenable mixtures containing only concrete over the time period relevant for construction. In a specific embodiment, a formula is provided that accurately predicts compressive strength of concrete containing fly ash out to 180 days. In other specific examples, concrete and mortar containing about 15% to 25% fly ash as a replacement for cement, which are capable of meeting design specifications required for building and highway construction, are provided. Such materials can thus significantly reduce construction costs.

  10. Compressive strength of concrete and mortar containing fly ash

    DOEpatents

    Liskowitz, John W.; Wecharatana, Methi; Jaturapitakkul, Chai; Cerkanowicz, deceased, Anthony E.

    1998-01-01

    The present invention relates to concrete, mortar and other hardenable mixtures comprising cement and fly ash for use in construction. The invention includes a method for predicting the compressive strength of such a hardenable mixture, which is very important for planning a project. The invention also relates to hardenable mixtures comprising cement and fly ash which can achieve greater compressive strength than hardenable mixtures containing only concrete over the time period relevant for construction. In a specific embodiment, a formula is provided that accurately predicts compressive strength of concrete containing fly ash out to 180 days. In other specific examples, concrete and mortar containing about 15% to 25% fly ash as a replacement for cement, which are capable of meeting design specification required for building and highway construction, are provided. Such materials can thus significantly reduce construction costs.

  11. Compressive strength of concrete and mortar containing fly ash

    DOEpatents

    Liskowitz, J.W.; Wecharatana, M.; Jaturapitakkul, C.; Cerkanowicz, A.E.

    1997-04-29

    The present invention relates to concrete, mortar and other hardenable mixtures comprising cement and fly ash for use in construction. The invention includes a method for predicting the compressive strength of such a hardenable mixture, which is very important for planning a project. The invention also relates to hardenable mixtures comprising cement and fly ash which can achieve greater compressive strength than hardenable mixtures containing only concrete over the time period relevant for construction. In a specific embodiment, a formula is provided that accurately predicts compressive strength of concrete containing fly ash out to 180 days. In other specific examples, concrete and mortar containing about 15% to 25% fly ash as a replacement for cement, which are capable of meeting design specifications required for building and highway construction, are provided. Such materials can thus significantly reduce construction costs. 33 figs.

  12. Compressive strength of concrete and mortar containing fly ash

    DOEpatents

    Liskowitz, J.W.; Wecharatana, M.; Jaturapitakkul, C.; Cerkanowicz, A.E.

    1998-12-29

    The present invention relates to concrete, mortar and other hardenable mixtures comprising cement and fly ash for use in construction. The invention includes a method for predicting the compressive strength of such a hardenable mixture, which is very important for planning a project. The invention also relates to hardenable mixtures comprising cement and fly ash which can achieve greater compressive strength than hardenable mixtures containing only concrete over the time period relevant for construction. In a specific embodiment, a formula is provided that accurately predicts compressive strength of concrete containing fly ash out to 180 days. In other specific examples, concrete and mortar containing about 15% to 25% fly ash as a replacement for cement, which are capable of meeting design specification required for building and highway construction, are provided. Such materials can thus significantly reduce construction costs. 33 figs.

  13. Mixture Experiments

    SciTech Connect

    Piepel, Gregory F.

    2007-12-01

    A mixture experiment involves combining two or more components in various proportions or amounts and then measuring one or more responses for the resulting end products. Other factors that affect the response(s), such as process variables and/or the total amount of the mixture, may also be studied in the experiment. A mixture experiment design specifies the combinations of mixture components and other experimental factors (if any) to be studied and the response variable(s) to be measured. Mixture experiment data analyses are then used to achieve the desired goals, which may include (i) understanding the effects of components and other factors on the response(s), (ii) identifying components and other factors with significant and nonsignificant effects on the response(s), (iii) developing models for predicting the response(s) as functions of the mixture components and any other factors, and (iv) developing end-products with desired values and uncertainties of the response(s). Given a mixture experiment problem, a practitioner must consider the possible approaches for designing the experiment and analyzing the data, and then select the approach best suited to the problem. Eight possible approaches include 1) component proportions, 2) mathematically independent variables, 3) slack variable, 4) mixture amount, 5) component amounts, 6) mixture process variable, 7) mixture of mixtures, and 8) multi-factor mixture. The article provides an overview of the mixture experiment designs, models, and data analyses for these approaches.

  14. Mass-fractal growth in niobia/silsesquioxane mixtures: a small-angle X-ray scattering study

    PubMed Central

    Besselink, Rogier; ten Elshof, Johan E.

    2014-01-01

    The nucleation and growth of niobium pentaethoxide (NPE)-derived clusters in ethanol, through acid-catalyzed hydrolysis/condensation in the presence and absence of the silsesquioxane 1,2-bis(triethoxysilyl)ethane (BTESE), was monitored at 298–333 K by small-angle X-ray scattering. The data were analyzed with a newly derived model for polydisperse mass-fractal-like structures. At 298–313 K in the absence of BTESE the data indicated the development of relatively monodisperse NPE-derived structures with self-preserving polydispersity during growth. The growth exponent was consistent with irreversible diffusion-limited cluster agglomeration. At 333 K the growth exponent was characteristic for fast-gelling reaction-limited cluster agglomeration. The reaction yielded substantially higher degrees of polydispersity. In the presence of BTESE the growth exponents were substantially smaller. The smaller growth exponent in this case is not consistent with irreversible Smoluchowski-type agglomeration. Instead, reversible Lifshitz–Slyozov-type agglomeration seems to be more consistent with the experimental data. PMID:25294980

  15. Enhancement in mechanical properties of concrete due to blended ash

    SciTech Connect

    Naik, T.R.; Singh, S.S.; Hossain, M.M.

    1996-01-01

    This study was carried out to evaluate the effects of blended ash mixture on mechanical properties of concrete. In this study two reference mixtures were used. One of the mixtures was a no-fly ash mixture, and the other mixture contained 35% unblended Class C fly ash. Additional mixtures were composed of three blends of Class C and Class F fly ash while maintaining a total fly ash content of 40% of the total cementitious materials. Mechanical properties such as compressive strength, tensile strength, flexural strength, and modulus of elasticity were determined as a function of age ranging from 1 to 91 days. The results showed that blending of Class F fly ash with Class C fly ash showed either comparable or better results compared to either the reference mixture without fly ash or the unblended Class C fly ash concrete mixture at a fly ash concentration of 40% of total cementitious materials.

  16. Electropositive bivalent metallic ion unsaturated polyester complexed polymer concrete

    DOEpatents

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

    1981-11-04

    Quick setting polymer concrete compositions which are mixtures of unsaturated polyesters and crosslinking monomers together with appropriate initiators and promoters in association with aggregate which may be wet and a source of bivalent metallic ions which will set to polymer concrete with excellent structural properties.

  17. Electropositive bivalent metallic ion unsaturated polyester complexed polymer concrete

    DOEpatents

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

    1983-05-13

    Quick setting polymer concrete compositions are described which are mixtures of unsaturated polyesters and crosslinking monomers together with appropriate initiators and promoters in association with aggregate which may be wet and a source of bivalent metallic ions which will set to polymer concrete with excellent structural properties.

  18. Electropositive bivalent metallic ion unsaturated polyester complexed polymer concrete

    DOEpatents

    Sugama, Toshifumi; Kukacka, Lawrence E.; Horn, William H.

    1985-01-01

    Quick setting polymer concrete compositions with excellent structural properties are disclosed; these polymer concrete compositions are mixtures of unsaturated polyesters and crosslinking monomers together with appropriate initiators and promoters in association with aggregate, which may be wet, and with a source of bivalent metallic ions.

  19. Characterization of polyoxyethylene tallow amine surfactants in technical mixtures and glyphosate formulations using ultra-high performance liquid chromatography and triple quadrupole mass spectrometry

    USGS Publications Warehouse

    Tush, Daniel; Loftin, Keith A.; Meyer, Michael T.

    2013-01-01

    Little is known about the occurrence, fate, and effects of the ancillary additives in pesticide formulations. Polyoxyethylene tallow amine (POEA) is a non-ionic surfactant used in many glyphosate formulations, a widely applied herbicide both in agricultural and urban environments. POEA has not been previously well characterized, but has been shown to be toxic to various aquatic organisms. Characterization of technical mixtures using ultra-high performance liquid chromatography (UHPLC) and mass spectrometry shows POEA is a complex combination of homologs of different aliphatic moieties and ranges of ethoxylate units. Tandem mass spectrometry experiments indicate that POEA homologs generate no product ions readily suitable for quantitative analysis due to poor sensitivity. A comparison of multiple high performance liquid chromatography (HPLC) and UHPLC analytical columns indicates that the stationary phase is more important in column selection than other parameters for the separation of POEA. Analysis of several agricultural and household glyphosate formulations confirms that POEA is a common ingredient but ethoxylate distributions among formulations vary.

  20. Matrix-Assisted Ionization-Ion Mobility Spectrometry-Mass Spectrometry: Selective Analysis of a Europium-PEG Complex in a Crude Mixture.

    PubMed

    Fischer, Joshua L; Lutomski, Corinne A; El-Baba, Tarick J; Siriwardena-Mahanama, Buddhima N; Weidner, Steffen M; Falkenhagen, Jana; Allen, Matthew J; Trimpin, Sarah

    2015-12-01

    The analytical utility of a new and simple to use ionization method, matrix-assisted ionization (MAI), coupled with ion mobility spectrometry (IMS) and mass spectrometry (MS) is used to characterize a 2-armed europium(III)-containing poly(ethylene glycol) (Eu-PEG) complex directly from a crude sample. MAI was used with the matrix 1,2-dicyanobenzene, which affords low chemical background relative to matrix-assisted laser desorption/ionization (MALDI) and electrospray ionization (ESI). MAI provides high ion abundance of desired products in comparison to ESI and MALDI. Inductively coupled plasma-MS measurements were used to estimate a maximum of 10% of the crude sample by mass was the 2-arm Eu-PEG complex, supporting evidence of selective ionization of Eu-PEG complexes using the new MAI matrix, 1,2-dicyanobenzene. Multiply charged ions formed in MAI enhance the IMS gas-phase separation, especially relative to the singly charged ions observed with MALDI. Individual components are cleanly separated and readily identified, allowing characterization of the 2-arm Eu-PEG conjugate from a mixture of the 1-arm Eu-PEG complex and unreacted starting materials. Size-exclusion chromatography, liquid chromatography at critical conditions, MALDI-MS, ESI-MS, and ESI-IMS-MS had difficulties with this analysis, or failed. Graphical Abstract ᅟ.

  1. Insight into unresolved complex mixtures of aromatic hydrocarbons in heavy oil via two-dimensional gas chromatography coupled with time-of-flight mass spectrometry analysis.

    PubMed

    Weng, Na; Wan, Shan; Wang, Huitong; Zhang, Shuichang; Zhu, Guangyou; Liu, Jingfu; Cai, Di; Yang, Yunxu

    2015-06-12

    The aromatic hydrocarbon fractions of five crude oils representing a natural sequence of increasing degree of biodegradation from the Liaohe Basin, NE, China, were analyzed using conventional gas chromatography-mass spectrometry (GC-MS) and comprehensive two-dimensional gas chromatography (GC×GC). Because of the limited peak capability and low resolution, compounds in the aromatic fraction of a heavily biodegraded crude oil that were analyzed by GC-MS appeared as unresolved complex mixtures (UCMs) or GC "humps". They could be separated based on their polarity by GC×GC. UCMs are composed mainly of aromatic biomarkers and aromatic hydrocarbons with branched alkanes or cycloalkanes substituents. The quantitative results achieved by GC×GC-FID were shown that monoaromatic hydrocarbons account for the largest number and mass of UCMs in the aromatic hydrocarbon fraction of heavily biodegraded crude oil, at 45% by mass. The number and mass of diaromatic hydrocarbons ranks second at 33% by mass, followed by the aromatic biomarker compounds, triaromatic, tetraaromatic, and pentaaromatic hydrocarbons, that account for 10%, 6%, 1.5%, and 0.01% of all aromatic compounds by mass, respectively. In the heavily biodegraded oil, compounds with monocyclic cycloalkane substituents account for the largest proportion of mono- and diaromatic hydrocarbons, respectively. The C4-substituted compounds account for the largest proportion of naphthalenes and the C3-substituted compounds account for the largest proportion of phenanthrenes, which is very different from non-biodegraded, slightly biodegraded, and moderately biodegraded crude oil. It is inferred that compounds of monoaromatic, diaromatic and triaromatic hydrocarbons are affected by biodegradation, that compounds with C1-, C2-substituents are affected by the increase in degree of biodegradation, and that their relative content decreased, whereas compounds with C3-substituents or more were affected slightly or unaffected, and their

  2. Congener-specific carbon isotopic analysis of technical PCB and PCN mixtures using two-dimensional gas chromatography-isotope ratio mass spectrometry.

    PubMed

    Horii, Yuichi; Kannan, Kurunthachalam; Petrick, Gert; Gamo, Toshitaka; Falandysz, Jerzy; Yamashita, Nobuyoshi

    2005-06-01

    Analysis of stable carbon isotope fractionation is a useful method to study the sources and fate of anthropogenic organic contaminants such as polychlorinated biphenyls (PCBs) in the environment. To evaluate the utility of carbon isotopes, determination of isotopic ratios of 13C/12C in source materials, for example, technical PCB preparations, is needed. In this study, we determined delta13C values of 31 chlorobiphenyl (CB) congeners in 18 technical PCB preparations and 15 chloronaphthalene (CN) congeners in 6 polychlorinated naphthalene preparations using two-dimensional gas chromatography-combustion furnace-isotope ratio mass spectrometry (2DGC-C-IRMS). Development of 2DGC-IRMS enabled improved resolution and sensitivity of compound-specific carbon isotope analysis (CSIA) of CB or CN congeners. Delta13C values of PCB congeners ranged from -34.4 (Delors) to -22.0/1000 (Sovol). Analogous PCB preparations with similar chlorine content, but different geographical origin, had different delta13C values. PCB preparations from Eastern European countries--Delors, Sovol, Trichlorodiphenyl, and Chlorofen--had distinct delta13C values. PCB mixtures showed increased 13C depletion with increasing chlorine content. Delta13C values for individual CB congeners varied depending on the degree of chlorination in technical mixtures. Delta13C values of CN congeners in Halowaxes ranged from -26.3 to -21.7/1000 and these values are within the ranges observed for PCBs. This study establishes the range of delta13C values in technical PCB and PCN preparations, which may prove to be useful in the determination of sources of these compounds in the environment. This is the first study to employ 2DGC-IRMS analysis of delta13C values in technical PCB and PCN preparations.

  3. Molecular composition of fresh and aged secondary organic aerosol from a mixture of biogenic volatile compounds: a high-resolution mass spectrometry study

    NASA Astrophysics Data System (ADS)

    Kourtchev, I.; Doussin, J.-F.; Giorio, C.; Mahon, B.; Wilson, E. M.; Maurin, N.; Pangui, E.; Venables, D. S.; Wenger, J. C.; Kalberer, M.

    2015-05-01

    Field observations over the past decade indicate that a significant fraction of organic aerosol in remote areas may contain highly oxidized molecules. Aerosol processing or further oxidation (aging) of organic aerosol has been suggested to be responsible for their formation through heterogeneous reaction with oxidants and multigenerational oxidation of vapours by OH radicals. In this study we investigated the influence of several aging processes on the molecular composition of secondary organic aerosols (SOA) using direct infusion and liquid chromatography high-resolution mass spectrometry. SOA was formed in simulation chamber experiments from ozonolysis of a mixture of four biogenic volatile organic compounds (BVOC): α-pinene, β-pinene, Δ3-carene and isoprene. The SOA was subsequently aged under three different sets of conditions: in the dark in the presence of residual ozone, with UV irradiation and OH radicals, and using UV light only. Among all studied conditions, only OH radical-initiated aging was found to influence the molecular composition of the aerosol and showed an increase in carbon oxidation state (OSC) and elemental O / C ratios of the SOA components. None of the aging processes produced an observable effect on the oligomers formed from ozonolysis of the BVOC mixture, which were found to be equally abundant in both "fresh" and "aged" SOA. Additional experiments using α-pinene as the sole precursor demonstrated that oligomers are an important group of compounds in SOA produced from both ozonolysis and OH radical-initiated oxidation processes; however, a completely different set of oligomers is formed under these two oxidation regimes. SOA from the OH-initiated oxidation of α-pinene had a significantly higher overall OSC and O / C compared to that from pure ozonolysis experiments confirming that the OH radical reaction is more likely to be responsible for the occurrence of highly oxidized species in ambient biogenic SOA.

  4. Mass

    SciTech Connect

    Quigg, Chris

    2007-12-05

    In the classical physics we inherited from Isaac Newton, mass does not arise, it simply is. The mass of a classical object is the sum of the masses of its parts. Albert Einstein showed that the mass of a body is a measure of its energy content, inviting us to consider the origins of mass. The protons we accelerate at Fermilab are prime examples of Einsteinian matter: nearly all of their mass arises from stored energy. Missing mass led to the discovery of the noble gases, and a new form of missing mass leads us to the notion of dark matter. Starting with a brief guided tour of the meanings of mass, the colloquium will explore the multiple origins of mass. We will see how far we have come toward understanding mass, and survey the issues that guide our research today.

  5. Investigation of gamma ray shielding efficiency and mechanical performances of concrete shields containing bismuth oxide as an environmentally friendly additive

    NASA Astrophysics Data System (ADS)

    Yao, Ya; Zhang, Xiaowen; Li, Mi; Yang, Rong; Jiang, Tianjiao; Lv, Junwen

    2016-10-01

    Concrete has a proven ability to attenuate gamma rays and neutrons without compromising structural property; therefore, it is widely used as the primary shielding material in many nuclear facilities. Recently, there is a tendency toward using various additives to enhance the shielding properties of these concrete mixtures. However, most of these additives being used either pose hygiene hazards or require special handling processes. It would be ideal if environmentally friendly additives were available for use. The bismuth oxide (Bi2O3) additive shows promise in various shielding applications due to its proven radiation attenuation ability and environmentally friendly nature. To the best of our knowledge, however, Bi2O3 has never been used in concrete mixtures. Therefore, for this research, we fabricated the Bi2O3-based concrete mixtures by adding Bi2O3 powder in the ordinary concrete mixture. Concrete mixtures with lead oxide (PbO) additives were used for comparison. Radiation shielding parameters like the linear attenuation coefficients (LAC) of all these concrete mixtures showing the effects of the Bi2O3 additions are presented. The mechanical performances of concrete mixtures incorporated with Bi2O3 additive were also investigated. It suggested that the concrete mixture containing 25% Bi2O3 powder (B5 in this study) provided the best shielding capacity and mechanical performance among other mixes. It has a significant potential for application as a structural concrete where radiological protection capability is required.

  6. The Apparent Thermal Conductivity of Pozzolana Concrete

    NASA Astrophysics Data System (ADS)

    Bessenouci, M. Z.; Triki, N. E. Bibi; Khelladi, S.; Draoui, B.; Abene, A.

    The recent development of some lightweight construction materials, such as light concrete, can play an important role as an insulator, while maintaining sufficient levels of mechanical performance. The quality of insulation to provide depends on the climate, the exposure of the walls and also the materials used in the construction. The choice of a material to be used as an insulator, obviously, depends on its availability and its cost. This is a study of natural pozzolanas as basic components in building materials. It is intended to highlight their thermal advantage. It is economically advantageous to use pozzolana in substitution for a portion of the clinker as hydraulically active additions, as well as in compositions of lightweight concretes in the form of pozzolanic aggregate mixtures, which provide mechanical strengths that comply with current standards. A theoretical study is conducted on the apparent thermal conductivity of building materials, namely concrete containing pozzolana. Thermal modeling, apparent to that commonly used for porous materials, has been applied to pozzolana concrete. Experimental results on measurements of the apparent thermal conductivity of pozzolana concrete are reported in this study, using an approach that considers that concrete is composed of two solid ingredients, a binding matrix (hydrated cement paste) and all aggregates. A second comparative theoretical approach is used for the case where concrete consists of a solid phase and a fluid phase (air).

  7. An investigation on the use of shredded waste PET bottles as aggregate in lightweight concrete

    SciTech Connect

    Akcaoezoglu, Semiha; Atis, Cengiz Duran; Akcaoezoglu, Kubilay

    2010-02-15

    In this work, the utilization of shredded waste Poly-ethylene Terephthalate (PET) bottle granules as a lightweight aggregate in mortar was investigated. Investigation was carried out on two groups of mortar samples, one made with only PET aggregates and, second made with PET and sand aggregates together. Additionally, blast-furnace slag was also used as the replacement of cement on mass basis at the replacement ratio of 50% to reduce the amount of cement used and provide savings. The water-binder (w/b) ratio and PET-binder (PET/b) ratio used in the mixtures were 0.45 and 0.50, respectively. The size of shredded PET granules used in the preparation of mortar mixtures were between 0 and 4 mm. The results of the laboratory study and testing carried out showed that mortar containing only PET aggregate, mortar containing PET and sand aggregate, and mortars modified with slag as cement replacement can be drop into structural lightweight concrete category in terms of unit weight and strength properties. Therefore, it was concluded that there is a potential for the use of shredded waste PET granules as aggregate in the production of structural lightweight concrete. The use of shredded waste PET granules due to its low unit weight reduces the unit weight of concrete which results in a reduction in the death weight of a structural concrete member of a building. Reduction in the death weight of a building will help to reduce the seismic risk of the building since the earthquake forces linearly dependant on the dead-weight. Furthermore, it was also concluded that the use of industrial wastes such as PET granules and blast-furnace slag in concrete provides some advantages, i.e., reduction in the use of natural resources, disposal of wastes, prevention of environmental pollution, and energy saving.

  8. An investigation on the use of shredded waste PET bottles as aggregate in lightweight concrete.

    PubMed

    Akçaözoğlu, Semiha; Atiş, Cengiz Duran; Akçaözoğlu, Kubilay

    2010-02-01

    In this work, the utilization of shredded waste Poly-ethylene Terephthalate (PET) bottle granules as a lightweight aggregate in mortar was investigated. Investigation was carried out on two groups of mortar samples, one made with only PET aggregates and, second made with PET and sand aggregates together. Additionally, blast-furnace slag was also used as the replacement of cement on mass basis at the replacement ratio of 50% to reduce the amount of cement used and provide savings. The water-binder (w/b) ratio and PET-binder (PET/b) ratio used in the mixtures were 0.45 and 0.50, respectively. The size of shredded PET granules used in the preparation of mortar mixtures were between 0 and 4 mm. The results of the laboratory study and testing carried out showed that mortar containing only PET aggregate, mortar containing PET and sand aggregate, and mortars modified with slag as cement replacement can be drop into structural lightweight concrete category in terms of unit weight and strength properties. Therefore, it was concluded that there is a potential for the use of shredded waste PET granules as aggregate in the production of structural lightweight concrete. The use of shredded waste PET granules due to its low unit weight reduces the unit weight of concrete which results in a reduction in the death weight of a structural concrete member of a building. Reduction in the death weight of a building will help to reduce the seismic risk of the building since the earthquake forces linearly dependent on the dead-weight. Furthermore, it was also concluded that the use of industrial wastes such as PET granules and blast-furnace slag in concrete provides some advantages, i.e., reduction in the use of natural resources, disposal of wastes, prevention of environmental pollution, and energy saving. PMID:19853433

  9. Guidelines for identification of concrete in a materials property database

    SciTech Connect

    Oland, C.B.; Frohnsdorff, G.

    1995-12-31

    Guidelines for the identification of concrete in a materials property database are presented to address the complex problem of distinguishing one concrete from another. These guidelines are based on a logical scheme for systematically organizing and subdividing data and information about concrete and its constituents; they reflect consensus recommendations for a multilevel material description and designation system. Aspects of the guidelines include a classification system used to establish a series of primary identifiers, methods for reporting constituent information and mixture proportions, fields describing the source of the concrete and its processing history, and recommendations for reporting baseline or reference properties.

  10. Evaluation of ternary blended cements for use in transportation concrete structures

    NASA Astrophysics Data System (ADS)

    Gilliland, Amanda Louise

    This thesis investigates the use of ternary blended cement concrete mixtures for transportation structures. The study documents technical properties of three concrete mixtures used in federally funded transportation projects in Utah, Kansas, and Michigan that used ternary blended cement concrete mixtures. Data were also collected from laboratory trial batches of ternary blended cement concrete mixtures with mixture designs similar to those of the field projects. The study presents the technical, economic, and environmental advantages of ternary blended cement mixtures. Different barriers of implementation for using ternary blended cement concrete mixtures in transportation projects are addressed. It was concluded that there are no technical, economic, or environmental barriers that exist when using most ternary blended cement concrete mixtures. The technical performance of the ternary blended concrete mixtures that were studied was always better than ordinary portland cement concrete mixtures. The ternary blended cements showed increased durability against chloride ion penetration, alkali silica reaction, and reaction to sulfates. These blends also had less linear shrinkage than ordinary portland cement concrete and met all strength requirements. The increased durability would likely reduce life cycle costs associated with concrete pavement and concrete bridge decks. The initial cost of ternary mixtures can be higher or lower than ordinary portland cement, depending on the supplementary cementitious materials used. Ternary blended cement concrete mixtures produce less carbon dioxide emissions than ordinary portland cement mixtures. This reduces the carbon footprint of construction projects. The barriers associated with implementing ternary blended cement concrete for transportation projects are not significant. Supplying fly ash returns any investment costs for the ready mix plant, including silos and other associated equipment. State specifications can make

  11. The effects of utilizing silica fume in Portland Cement Pervious Concrete

    NASA Astrophysics Data System (ADS)

    Mann, Daniel Allen

    Silica fume has long been used as a supplementary cementing material to provide a high density, high strength, and durable building material. Silica fume has a particle size a fraction of any conventional cement, which allows it to increase concrete strength by decreasing the porosity especially near the aggregates surface. Because Portland Cement Pervious Concrete (PCPC) has a smaller bond area between aggregate and paste, silica fume has significant impacts on the properties of the PCPC. The research in this paper studies the workability of a cement paste containing silica fume in addition to analyzing the results of testing on Portland Cement Pervious Concrete mixtures that also contained silica fume. Testing conducted included a study of the effects of silica fume on cement's rheological properties at various dosage rates ranging from zero to ten percent by mass. It was determined that silica fume has negligible effects on the viscosity of cement paste until a dosage rate of five percent, at which point the viscosity increases rapidly. In addition to the rheological testing of the cement paste, trials were also conducted on the pervious concrete samples. Sample groups included mixes with river gravel and chipped limestone as aggregate, washed and unwashed, and two different void contents. Workability tests showed that mixtures containing a silica fume dosage rate of 5 percent or less had comparable or slightly improved workability when compared to control groups. Workability was found to decrease at a 7 percent dosage rate. Samples were tested for compressive strength at 7 and 28 days and splitting tensile strength at 28 days. It was found in most sample groups, strength increased with dosage rates of 3 to 5 percent but often decreased when the dosage reached 7 percent. Abrasion testing showed that both samples containing washed aggregate and samples containing silica fume exhibited a reduced mass loss.

  12. Environmental performance and mechanical analysis of concrete containing recycled asphalt pavement (RAP) and waste precast concrete as aggregate.

    PubMed

    Erdem, Savaş; Blankson, Marva Angela

    2014-01-15

    The overall objective of this research project was to investigate the feasibility of incorporating 100% recycled aggregates, either waste precast concrete or waste asphalt planning, as replacements for virgin aggregates in structural concrete and to determine the mechanical and environmental performance of concrete containing these aggregates. Four different types of concrete mixtures were designed with the same total water cement ratio (w/c=0.74) either by using natural aggregate as reference or by totally replacing the natural aggregate with recycled material. Ground granulated blast furnace slag (GGBS) was used as a mineral addition (35%) in all mixtures. The test results showed that it is possible to obtain satisfactory performance for strength characteristics of concrete containing recycled aggregates, if these aggregates are sourced from old precast concrete. However, from the perspective of the mechanical properties, the test results indicated that concrete with RAP aggregate cannot be used for structural applications. In terms of leaching, the results also showed that the environmental behaviour of the recycled aggregate concrete is similar to that of the natural aggregate concrete. PMID:24316812

  13. Environmental performance and mechanical analysis of concrete containing recycled asphalt pavement (RAP) and waste precast concrete as aggregate.

    PubMed

    Erdem, Savaş; Blankson, Marva Angela

    2014-01-15

    The overall objective of this research project was to investigate the feasibility of incorporating 100% recycled aggregates, either waste precast concrete or waste asphalt planning, as replacements for virgin aggregates in structural concrete and to determine the mechanical and environmental performance of concrete containing these aggregates. Four different types of concrete mixtures were designed with the same total water cement ratio (w/c=0.74) either by using natural aggregate as reference or by totally replacing the natural aggregate with recycled material. Ground granulated blast furnace slag (GGBS) was used as a mineral addition (35%) in all mixtures. The test results showed that it is possible to obtain satisfactory performance for strength characteristics of concrete containing recycled aggregates, if these aggregates are sourced from old precast concrete. However, from the perspective of the mechanical properties, the test results indicated that concrete with RAP aggregate cannot be used for structural applications. In terms of leaching, the results also showed that the environmental behaviour of the recycled aggregate concrete is similar to that of the natural aggregate concrete.

  14. Immobilization of iodine in concrete

    DOEpatents

    Clark, Walter E.; Thompson, Clarence T.

    1977-04-12

    A method for immobilizing fission product radioactive iodine recovered from irradiated nuclear fuel comprises combining material comprising water, Portland cement and about 3-20 wt. % iodine as Ba(IO.sub.3).sub.2 to provide a fluid mixture and allowing the fluid mixture to harden, said Ba(IO.sub.3).sub.2 comprising said radioactive iodine. An article for solid waste disposal comprises concrete prepared by this method. BACKGROUND OF THE INVENTION This invention was made in the course of, or under a contract with the Energy Research and Development Administration. It relates in general to reactor waste solidification and more specifically to the immobilization of fission product radioactive iodine recovered from irradiated nuclear fuel for underground storage.

  15. The effect of recycled concrete aggregate properties on the bond strength between RCA concrete and steel reinforcement

    SciTech Connect

    Butler, L. West, J.S.; Tighe, S.L.

    2011-10-15

    The purpose of this study was to investigate the influence that replacing natural coarse aggregate with recycled concrete aggregate (RCA) has on concrete bond strength with reinforcing steel. Two sources of RCA were used along with one natural aggregate source. Numerous aggregate properties were measured for all aggregate sources. Two types of concrete mixture proportions were developed replacing 100% of the natural aggregate with RCA. The first type maintained the same water-cement ratios while the second type was designed to achieve the same compressive strengths. Beam-end specimens were tested to determine the relative bond strength of RCA and natural aggregate concrete. On average, natural aggregate concrete specimens had bond strengths that were 9 to 19% higher than the equivalent RCA specimens. Bond strength and the aggregate crushing value seemed to correlate well for all concrete types.

  16. Lunar concrete for construction

    NASA Technical Reports Server (NTRS)

    Cullingford, Hatice S.; Keller, M. Dean

    1992-01-01

    Feasibility of using concrete for lunar base construction was discussed recently without relevant data for the effects of vacuum on concrete. Our experimental studies performed earlier at Los Alamos have shown that concrete is stable in vacuum with no deterioration of its quality as measured by the compressive strength. Various considerations of using concrete successfully on the Moon are provided in this paper, along with specific conclusions from the existing database.

  17. Lunar concrete for construction

    NASA Technical Reports Server (NTRS)

    Cullingford, Hatice S.; Keller, M. Dean

    1988-01-01

    Feasibility of using concrete for lunar-base construction has been discussed recently without relevant data for the effects of vacuum on concrete. Experimental studies performed earlier at Los Alamos have shown that concrete is stable in vacuum with no deterioration of its quality as measured by the compressive strength. Various considerations of using concrete successfully on the moon are provided in this paper along with specific conclusions from the existing data base.

  18. Concrete radiation shielding

    SciTech Connect

    Kaplan, M.F.

    1989-01-01

    This book presents an introduction to the aspects of nuclear physics relevant to concrete technology. It covers a variety of materials that may be used to produce concrete for radiation shielding. Details of the physical, mechanical, and nuclear properties of these concretes are provided, and their applications in nuclear waste storage, shelter design, and reactor shielding are described. Radiation shield design considerations are addressed.

  19. Reusing recycled aggregates in structural concrete

    NASA Astrophysics Data System (ADS)

    Kou, Shicong

    The utilization of recycled aggregates in concrete can minimize environmental impact and reduce the consumption of natural resources in concrete applications. The aim of this thesis is to provide a scientific basis for the possible use of recycled aggregates in structure concrete by conducting a comprehensive programme of laboratory study to gain a better understanding of the mechanical, microstructure and durability properties of concrete produced with recycled aggregates. The study also explored possible techniques to of improve the properties of recycled aggregate concrete that is produced with high percentages (≧ 50%) of recycled aggregates. These techniques included: (a) using lower water-to-cement ratios in the concrete mix design; (b) using fly ash as a cement replacement or as an additional mineral admixture in the concrete mixes, and (c) precasting recycled aggregate concrete with steam curing regimes. The characteristics of the recycled aggregates produced both from laboratory and a commercially operated pilot construction and demolition (C&D) waste recycling plant were first studied. A mix proportioning procedure was then established to produce six series of concrete mixtures using different percentages of recycled coarse aggregates with and without the use of fly ash. The water-to-cement (binder) ratios of 0.55, 0.50, 0.45 and 0.40 were used. The fresh properties (including slump and bleeding) of recycled aggregate concrete (RAC) were then quantified. The effects of fly ash on the fresh and hardened properties of RAC were then studied and compared with those RAC prepared with no fly ash addition. Furthermore, the effects of steam curing on the hardened properties of RAC were investigated. For micro-structural properties, the interfacial transition zones of the aggregates and the mortar/cement paste were analyzed by SEM and EDX-mapping. Moreover, a detailed set of results on the fracture properties for RAC were obtained. Based on the experimental

  20. Carcinogenic mixtures.

    PubMed

    Krewski, D; Thomas, R D

    1992-03-01

    Human populations are generally exposed simultaneously to a number of toxicants present in the environment, including complex mixtures of unknown and variable origin. While scientific methods for evaluating the potential carcinogenic risks of pure compounds are relatively well established, methods for assessing the risks of complex mixtures are somewhat less developed. This article provides a report of a recent workshop on carcinogenic mixtures sponsored by the Committee on Toxicology of the U.S. National Research Council, in which toxicological, epidemiological, and statistical approaches to carcinogenic risk assessment for mixtures were discussed. Complex mixtures, such as diesel emissions and tobacco smoke, have been shown to have carcinogenic potential. Bioassay-directed fractionation based on short-term screening test for genotoxicity has also been used in identifying carcinogenic components of mixtures. Both toxicological and epidemiological studies have identified clear interactions between chemical carcinogens, including synergistic effects at moderate to high doses. To date, laboratory studies have demonstrated over 900 interactions involving nearly 200 chemical carcinogens. At lower doses, theoretical arguments suggest that risks may be near additive. Thus, additivity at low doses has been invoked as as a working hypothesis by regulatory authorities in the absence of evidence to the contrary. Future studies of the joint effects of carcinogenic agents may serve to elucidate the mechanisms by which interactions occur at higher doses.

  1. Radon emanation fractions from concretes containing fly ash and metakaolin.

    PubMed

    Taylor-Lange, Sarah C; Juenger, Maria C G; Siegel, Jeffrey A

    2014-01-01

    Radon ((222)Rn) and progenies emanate from soil and building components and can create an indoor air quality hazard. In this study, nine concrete constituents, including the supplementary cementitious materials (SCMs) fly ash and metakaolin, were used to create eleven different concrete mixtures. We investigated the effect of constituent radium specific activity, radon effective activity and emanation fraction on the concrete emanation fraction and the radon exhalation rate. Given the serious health effects associated with radionuclide exposure, experimental results were coupled with Monte Carlo simulations to demonstrate predictive differences in the indoor radon concentration due to concrete mixture design. The results from this study show that, on average, fly ash constituents possessed radium specific activities ranging from 100 Bq/kg to 200 Bq/kg and emanation fractions ranging from 1.1% to 2.5%. The lowest emitting concrete mixture containing fly ash resulted in a 3.4% reduction in the concrete emanation fraction, owing to the relatively low emanation that exists when fly ash is part of concrete. On average, the metakaolin constituents contained radium specific activities ranging from 67 Bq/kg to 600 Bq/kg and emanation fractions ranging from 8.4% to 15.5%, and changed the total concrete emanation fraction by roughly ±5% relative to control samples. The results from this study suggest that SCMs can reduce indoor radon exposure from concrete, contingent upon SCM radionucleotide content and emanation fraction. Lastly, the experimental results provide SCM-specific concrete emanation fractions for indoor radon exposure modeling.

  2. Controlling chloride ions diffusion in concrete.

    PubMed

    Zeng, Lunwu; Song, Runxia

    2013-11-28

    The corrosion of steel in concrete is mainly due to the chemical reaction between the chloride ions and iron ions. Indeed, this is a serious threaten for reinforced concrete structure, especially for the reinforced concrete structure in the sea. So it is urgent and important to protect concrete against chloride ions corrosion. In this work, we report multilayer concrete can cloak chloride ions. We formulated five kinds of concrete A, B, C, D and E, which are made of different proportion of cement, sand and glue, and fabricated six-layer (ABACAD) cylinder diffusion cloak and background media E. The simulation results show that the six-layer mass diffusion cloak can protect concrete against chloride ions penetration, while the experiment results show that the concentration gradients are parallel and equal outside the outer circle in the diffusion flux lines, the iso-concentration lines are parallel outside the outer circle, and the concentration gradients in the inner circle are smaller than those outside the outer circle.

  3. Controlling chloride ions diffusion in concrete

    PubMed Central

    Zeng, Lunwu; Song, Runxia

    2013-01-01

    The corrosion of steel in concrete is mainly due to the chemical reaction between the chloride ions and iron ions. Indeed, this is a serious threaten for reinforced concrete structure, especially for the reinforced concrete structure in the sea. So it is urgent and important to protect concrete against chloride ions corrosion. In this work, we report multilayer concrete can cloak chloride ions. We formulated five kinds of concrete A, B, C, D and E, which are made of different proportion of cement, sand and glue, and fabricated six-layer (ABACAD) cylinder diffusion cloak and background media E. The simulation results show that the six-layer mass diffusion cloak can protect concrete against chloride ions penetration, while the experiment results show that the concentration gradients are parallel and equal outside the outer circle in the diffusion flux lines, the iso-concentration lines are parallel outside the outer circle, and the concentration gradients in the inner circle are smaller than those outside the outer circle. PMID:24285220

  4. Sulfate resistance of high calcium fly ash concrete

    NASA Astrophysics Data System (ADS)

    Dhole, Rajaram

    Sulfate attack is one of the mechanisms which can cause deterioration of concrete. In general, Class C fly ash mixtures are reported to provide poor sulfate resistance. Fly ashes, mainly those belonging to the Class C, were tested as per the ASTM C 1012 procedure to evaluate chemical sulfate resistance. Overall the Class C fly ashes showed poor resistance in the sulfate environment. Different strategies were used in this research work to improve the sulfate resistance of Class C fly ash mixes. The study revealed that some of the strategies such as use of low W/CM (water to cementing materials by mass ratio), silica fume or ultra fine fly ash, high volumes of fly ash and, ternary or quaternary mixes with suitable supplementary cementing materials, can successfully improve the sulfate resistance of the Class C fly ash mixes. Combined sulfate attack, involving physical and chemical action, was studied using sodium sulfate and calcium sulfate solutions. The specimens were subjected to wetting-drying cycles and temperature changes. These conditions were found to accelerate the rate of degradation of concrete placed in a sodium sulfate environment. W/CM was found to be the main governing factor in providing sulfate resistance to mixes. Calcium sulfate did not reveal damage as a result of mainly physical action. Characterization of the selected fly ashes was undertaken by using SEM, XRD and the Rietveld analysis techniques, to determine the relation between the composition of fly ashes and resistance to sulfate attack. The chemical composition of glass represented on the ternary diagram was the main factor which had a significant influence on the sulfate resistance of fly ash mixtures. Mixes prepared with fly ashes containing significant amounts of vulnerable crystalline phases offered poor sulfate resistance. Comparatively, fly ash mixes containing inert crystalline phases such as quartz, mullite and hematite offered good sulfate resistance. The analysis of hydrated lime

  5. Lunar concrete: Prospects and challenges

    NASA Astrophysics Data System (ADS)

    Khitab, Anwar; Anwar, Waqas; Mehmood, Imran; Kazmi, Syed Minhaj Saleem; Munir, Muhammad Junaid

    2016-02-01

    The possibility of using concrete as a construction material at the Moon surface is considered. Dissimilarities between the Earth and the Moon and their possible effects on concrete are also emphasized. Availability of constituent materials for concrete at lunar surface is addressed. An emphasis is given to two types of materials, namely, hydraulic concrete and sulfur concrete. Hydraulic concrete necessitates the use of water and sulfur concrete makes use of molten sulfur in lieu of cement and water.

  6. Liquid chromatography "on-flow" 1H nuclear magnetic resonance on native glycosphingolipid mixtures together with gas chromatography/mass spectrometry on the released oligosaccharides for screening and characterisation of carbohydrate-based antigens from pig lungs.

    PubMed

    Bäcker, A E; Thorbert, S; Rakotonirainy, O; Hallberg, E C; Olling, A; Gustavsson, M; Samuelsson, B E; Soussi, B

    1999-01-01

    Glycosphingolipids were prepared from pig lung and pooled into two fractions with (i) < or = 3 sugar residues, and (ii) > or = 3 sugar residues. Oligosaccharides were prepared and used for gas chromatography, gas chromatography/mass spectrometry and matrix-assisted laser desorption/ionization mass spectrometry. The glycolipid fractions i and ii were further characterised and purified using a novel method based on high performance liquid chromatography "on-flow" proton nuclear magnetic resonance. The LC "on-flow" NMR technique showed good chromatographic separation and gave NMR spectral information which could be used as guidance for pooling of the separated mixture glycolipids. Conventional 1H NMR, thin layer immunostaining, gas chromatography, gas chromatography/mass spectrometry and matrix-assisted laser desorption/ionization mass spectrometry were used to characterise the glycolipids and to validate LC-NMR spectral data.

  7. Investigating Radiation Shielding Properties of Different Mineral Origin Heavyweight Concretes

    SciTech Connect

    Basyigit, Celalettin; Uysal, Volkan; Kilincarslan, Semsettin; Akkas, Ayse; Mavi, Betuel; Guenoglu, Kadir; Akkurt, Iskender

    2011-12-26

    The radiation although has hazardous effects for human health, developing technologies bring lots of usage fields to radiation like in medicine and nuclear power station buildings. In this case protecting from undesirable radiation is a necessity for human health. Heavyweight concrete is one of the most important materials used in where radiation should be shielded, like those areas. In this study, used heavyweight aggregates of different mineral origin (Limonite, Siderite), in order to prepare different series in concrete mixtures and investigated radiation shielding properties. The experimental results on measuring the radiation shielding, the heavyweight concrete prepared with heavyweight aggregates of different mineral origin show that, are useful radiation absorbents when they used in concrete mixtures.

  8. Biomarker- and similarity coefficient-based approaches to bacterial mixture characterization using matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS)

    PubMed Central

    Zhang, Lin; Smart, Sonja; Sandrin, Todd R

    2015-01-01

    MALDI-TOF MS profiling has been shown to be a rapid and reliable method to characterize pure cultures of bacteria. Currently, there is keen interest in using this technique to identify bacteria in mixtures. Promising results have been reported with two- or three-isolate model systems using biomarker-based approaches. In this work, we applied MALDI-TOF MS-based methods to a more complex model mixture containing six bacteria. We employed: 1) a biomarker-based approach that has previously been shown to be useful in identification of individual bacteria in pure cultures and simple mixtures and 2) a similarity coefficient-based approach that is routinely and nearly exclusively applied to identification of individual bacteria in pure cultures. Both strategies were developed and evaluated using blind-coded mixtures. With regard to the biomarker-based approach, results showed that most peaks in mixture spectra could be assigned to those found in spectra of each component bacterium; however, peaks shared by two isolates as well as peaks that could not be assigned to any individual component isolate were observed. For two-isolate blind-coded samples, bacteria were correctly identified using both similarity coefficient- and biomarker-based strategies, while for blind-coded samples containing more than two isolates, bacteria were more effectively identified using a biomarker-based strategy. PMID:26537565

  9. Sulfate and acid resistant concrete and mortar

    DOEpatents

    Liskowitz, J.W.; Wecharatana, M.; Jaturapitakkul, C.; Cerkanowicz, A.E.

    1998-06-30

    The present invention relates to concrete, mortar and other hardenable mixtures comprising cement and fly ash for use in construction and other applications, which hardenable mixtures demonstrate significant levels of acid and sulfate resistance while maintaining acceptable compressive strength properties. The acid and sulfate hardenable mixtures of the invention containing fly ash comprise cementitious materials and a fine aggregate. The cementitous materials may comprise fly ash as well as cement. The fine aggregate may comprise fly ash as well as sand. The total amount of fly ash in the hardenable mixture ranges from about 60% to about 120% of the total amount of cement, by weight, whether the fly ash is included as a cementious material, fine aggregate, or an additive, or any combination of the foregoing. In specific examples, mortar containing 50% fly ash and 50% cement in cementitious materials demonstrated superior properties of corrosion resistance. 6 figs.

  10. Sulfate and acid resistant concrete and mortar

    DOEpatents

    Liskowitz, John W.; Wecharatana, Methi; Jaturapitakkul, Chai; Cerkanowicz, deceased, Anthony E.

    1998-01-01

    The present invention relates to concrete, mortar and other hardenable mixtures comprising cement and fly ash for use in construction and other applications, which hardenable mixtures demonstrate significant levels of acid and sulfate resistance while maintaining acceptable compressive strength properties. The acid and sulfate hardenable mixtures of the invention containing fly ash comprise cementitious materials and a fine aggregate. The cementitous materials may comprise fly ash as well as cement. The fine aggregate may comprise fly ash as well as sand. The total amount of fly ash in the hardenable mixture ranges from about 60% to about 120% of the total amount of cement, by weight, whether the fly ash is included as a cementious material, fine aggregate, or an additive, or any combination of the foregoing. In specific examples, mortar containing 50% fly ash and 50% cement in cementitious materials demonstrated superior properties of corrosion resistance.

  11. Early-age volume changes of extrudable reactive powder concrete

    NASA Astrophysics Data System (ADS)

    Cherkaoui, K.; Courtial, M.; Dunstetter, F.; Khelidj, A.; Mounanga, P.; de Noirfontaine, M. N.

    2010-06-01

    This article presents a study on the early-age autogenous deformations of Extrudable Reactive Powder Concretes (ERPCs), especially designed for the making of concrete pipes by extrusion. Different ERPC mixtures, with variable amounts of polycarboxylate superplasticizer (SP), have been investigated. Results on 28-day mechanical properties, early-age hydration rate, autogenous shrinkage and premature cracking risk are analyzed and discussed in relation with the ERPC mix parameters.

  12. Investigation of gamma-ray shielding properties of concrete containing different percentages of lead.

    PubMed

    Rezaei-Ochbelagh, D; Azimkhani, S

    2012-10-01

    In this work, concrete mixed with different percentages of lead is used to study gamma-ray shielding properties. The transmitted fluxes of gamma-rays that were emitted from (137)Cs and (60)Co sources were detected by a NaI(Tl) detector and analyzed by a MCA analyzer. Then, linear attenuation coefficients (LAC) and compressive strength of concrete specimens were experimentally investigated. By comparing the obtained data from concrete specimens with and without lead, it was observed that, if the powder of lead to cement ratio of 90% by weight is added in the concrete mixture, the concrete can be used as a suitable shield against gamma rays. PMID:22854173

  13. Fly ash sulfur concrete

    SciTech Connect

    Head, W.J.; Liao, M.

    1981-05-01

    Two waste products, flyash and elemental sulfur, can be combined with a modifying agent to produce a potentially useful construction material, flyash sulfur concrete. Manufacturing processes and characteristics of this concrete are described. Compared with a conventional crushed stone aggregate, flyash sulfur concrete is a viable highway pavement base course material. The material's strength characteristics are analyzed. (1 diagram, 4 graphs, 2 photos, 9 references, 5 tables)

  14. Waste tyre rubberized concrete: properties at fresh and hardened state.

    PubMed

    Aiello, M A; Leuzzi, F

    2010-01-01

    The main objective of this paper is to investigate the properties of various concrete mixtures at fresh and hardened state, obtained by a partial substitution of coarse and fine aggregate with different volume percentages of waste tyres rubber particles, having the same dimensions of the replaced aggregate. Workability, unit weight, compressive and flexural strength and post-cracking behaviour were evaluated and a comparison of the results for the different rubcrete mixtures were proposed in order to define the better mix proportions in terms of mechanical properties of the rubberized concrete. Results showed in this paper were also compared to data reported in literature. Moreover, a preliminary geometrical, physical and mechanical characterization on scrap tyre rubber shreds was made. The rubberized concrete mixtures showed lower unit weight compared to plain concrete and good workability. The results of compressive and flexural tests indicated a larger reduction of mechanical properties of rubcrete when replacing coarse aggregate rather than fine aggregate. On the other hand, the post-cracking behaviour of rubberized concrete was positively affected by the substitution of coarse aggregate with rubber shreds, showing a good energy absorption and ductility indexes in the range observed for fibrous concrete, as suggested by standard (ASTM C1018-97, 1997).

  15. Application of ultraperformance liquid chromatography/mass spectrometry-based metabonomic techniques to analyze the joint toxic action of long-term low-level exposure to a mixture of organophosphate pesticides on rat urine profile.

    PubMed

    Du, Longfei; Wang, Hong; Xu, Wei; Zeng, Yan; Hou, Yurong; Zhang, Yuqiu; Zhao, Xiujuan; Sun, Changhao

    2013-07-01

    In previously published articles, we evaluated the toxicity of four organophosphate (OP) pesticides (dichlorvos, dimethoate, acephate, and phorate) to rats using metabonomic technology at their corresponding no observed adverse effect level (NOAEL). Results show that a single pesticide elicits no toxic response. This study aimed to determine whether chronic exposure to a mixture of the above four pesticides (at their corresponding NOAEL) can lead to joint toxic action in rats using the same technology. Pesticides were administered daily to rats through drinking water for 24 weeks. The above mixture of the four pesticides showed joint toxic action at the NOAEL of each pesticide. The metabonomic profiles of rats urine were analyzed by ultraperformance liquid chromatography/mass spectrometry. The 16 metabolites statistically significantly changed in all treated groups compared with the control group. Dimethylphosphate and dimethyldithiophosphate exclusively detected in all treated groups can be used as early, sensitive biomarkers for exposure to a mixture of the OP pesticides. Moreover, exposure to the OP pesticides resulted in increased 7-methylguanine, ribothymidine, cholic acid, 4-pyridoxic acid, kynurenine, and indoxyl sulfate levels, as well as decreased hippuric acid, creatinine, uric acid, gentisic acid, C18-dihydrosphingosine, phytosphingosine, suberic acid, and citric acid. The results indicated that a mixture of OP pesticides induced DNA damage and oxidative stress, disturbed the metabolism of lipids, and interfered with the tricarboxylic acid cycle. Ensuring food safety requires not only the toxicology test data of each pesticide for the calculation of the acceptable daily intake but also the joint toxic action.

  16. Some engineering properties of heavy concrete added silica fume

    SciTech Connect

    Akkaş, Ayşe; Başyiğit, Celalettin; Esen, Serap

    2013-12-16

    Many different types of building materials have been used in building construction for years. Heavy concretes can be used as a building material for critical building as it can contain a mixture of many heavy elements. The barite itself for radiation shielding can be used and also in concrete to produce the workable concrete with a maximum density and adequate structural strength. In this study, some engineering properties like compressive strength, elasticity modules and flexure strength of heavy concretes’ added Silica fume have been investigated.

  17. NATURE OF UNRESOLVED COMPLEX MIXTURE IN SIZE-DISTRIBUTED EMISSIONS FROM RESIDENTIAL WOOD COMBUSTION AS MEASURED BY THERMAL DESORPTION-GAS CHROMATOGRAPHY-MASS SPECTROMETRY

    EPA Science Inventory

    In this study, the unresolved complex mixture (UCM) in size resolved fine aerosol emissions from residential wood combustion (RWC) is examined. The aerosols are sorted by size in an electrical low-pressure impactor (ELPI) and subsequently analyzed by thermal desorbtion/gas chroma...

  18. Aggregate assesment and durability evaluation of optimized graded concrete in the state of Oklahoma

    NASA Astrophysics Data System (ADS)

    Ghaeezadeh, Ashkan

    This research is a part of a larger project that emphasizes on creating a more scientific approach to designing concrete mixtures for concrete pavements that use less cement and more aggregate which is called optimized graded concrete. The most challenging obstacle in optimized mixtures is reaching enough workability so that one doesn't have to add more cement or super-plasticizer to reach the desired level of flowability. Aggregate gradation and characteristics have found to be very important when it comes to the workabaility of optimized graded concrete. In this research a new automated method of aggregate assessment was used to compare the shape and the surface of different aggregates as well as their influence on the concrete flowability. At the end, the performance of optimized graded concrete against drying shrinkage and freezing and thawing condition were investigated.

  19. Effective determination of the long-lived nuclide 41Ca in nuclear reactor bioshield concretes: comparison of liquid scintillation counting and accelerator mass spectrometry.

    PubMed

    Warwick, P E; Croudace, I W; Hillegonds, D J

    2009-03-01

    The routine application of liquid scintillation counting to (41)Ca determination has been hindered by the absence of traceable calibration standards of known (41)Ca activity concentrations. The introduction of the new IRMM (41)Ca mass-spectrometric standards with sufficiently high (41)Ca activities for radiometric detection has partly overcome this although accurate measurement of stable Ca concentrations coupled with precise half-life data are still required to correct the certified (41)Ca:(40)Ca ratios to (41)Ca activity concentrations. In this study, (41)Ca efficiency versus quench curves have been produced using the IRMM standard, and their accuracy validated by comparison with theoretical calculations of (41)Ca efficiencies. Further verification of the technique was achieved through the analysis of (41)Ca in a reactor bioshield core that had been previously investigated for other radionuclide variations. Calcium-41 activity concentrations of up to 25 Bq/g were detected. Accelerator mass spectrometry (AMS) measurements of the same suite of samples showed a very good agreement, providing validation of the procedure. Calcium-41 activity concentrations declined exponentially with distance from the core of the nuclear reactor and correlated well with the predicted neutron flux.

  20. Pedogenic Carbonate Concretions in the Russian Chernozem

    SciTech Connect

    Mikhailova, E. A.; Post, C. J.; Magrini-Bair, K.; Castle, J. W.

    2006-12-01

    Pedogenic carbonate concretions are commonly found in grassland soils, but their origin is not fully understood. This study was conducted to determine the radiocarbon age, the stable isotope geochemistry, and chemical composition of carbonate concretions in the Russian Chernozem, one of the typical soils in grasslands. Three sites were sampled: a native grassland field (not cultivated for at least 300 years), an adjacent 50-year continuous fallow field in the V. V. Alekhin Central-Chernozem Biosphere State Reserve in the Kursk region of Russia, and a continuously cropped field in the Experimental Station of the Kursk Institute of Agronomy and Soil Erosion Control. All sampled soils were classified as fine-silty, mixed, frigid Pachic Hapludolls. The mineralogical composition of concretions varies from low-magnesium calcite to pure calcite. The concretion contains 0.05% N, 6.4% C, and has [delta]13C and [delta]18O values of -10.9[per mille sign] (the per mill symbol, parts per thousand) and -7.8[per mille sign], respectively. The outside part of the carbonate concretion is 1909 +/- 40 14C age Before Present (B.P.) compared with 1693 +/- 40 14C age B.P. for the inside part of the same concretion, even though the concretion is found in the C horizon of much older age (10,902 +/- 63 14C age B.P.). Remnants of soil organic matter in concretions are closely associated with the cropped and fallow/plowed soils by pyrolysis molecular beam mass spectrometry.

  1. Investigation of modified asphalt concrete

    NASA Astrophysics Data System (ADS)

    Zimich, Vita

    2016-01-01

    Currently the problem of improving the asphalt quality is very urgent. It is used primarily as topcoats exposed to the greatest relative to the other layers of the road, dynamic load - impact and shear. The number of cars on the road, the speed of their movement, as well as the traffic intensity increase day by day. We have to upgrade motor roads, which entails a huge cost. World experience shows that the issue is urgent not only in Russia, but also in many countries in Europe, USA and Asia. Thus, the subject of research is the resistance of asphalt concrete to water and its influence on the strength of the material at different temperatures, and resistance of pavement to deformation. It is appropriate to search for new modifiers for asphaltic binder and mineral additives for asphalt mix to form in complex the skeleton of the future asphalt concrete, resistant to atmospheric condensation, soil characteristics of the road construction area, as well as the growing road transport load. The important task of the work is searching special modifying additives for bitumen binder and asphalt mixture as a whole, which will improve the quality of highways, increasing the period between repairs. The methods described in the normative-technical documentation were used for the research. The conducted research allowed reducing the frequency of road maintenance for 7 years, increasing it from 17 to 25 years.

  2. Mass Spectrometric and Langmuir Probe Measurements in Inductively Coupled Plasmas in Ar, CHF3/Ar and CHF3/Ar/O2 Mixtures

    NASA Technical Reports Server (NTRS)

    Kim, J. S.; Rao, M. V. V. S.; Cappelli, M. A.; Sharma, S. P.; Meyyappan, M.; Arnold, Jim (Technical Monitor)

    2000-01-01

    Absolute fluxes and energy distributions of ions in inductively coupled plasmas of Ar, CHF3/Ar, and CHF3/Ar/O2 have been measured. These plasmas were generated in a Gaseous Electronics Conference (GEC) cell modified for inductive coupling at pressures 10-50 mTorr and 100-300 W of 13.56 MHz radio frequency (RF) power in various feedgas mixtures. In pure Ar plasmas, the Ar(+) flux increases linearly with pressure as well as RF-power. Total ion flux in CHF3 mixtures decreases with increase in pressure and also CHF3 concentration. Relative ion fluxes observed in the present studies are analyzed with the help of available cross sections for electron impact ionization and charge-exchange ion-molecule reactions. Measurements of plasma potential, electron and ion number densities, electron energy distribution function, and mean electron energy have also been made in the center of the plasma with a RF compensated Langmuir probe. Plasma potential values are compared with the mean ion energies determined from the measured ion energy distributions and are consistent. Electron temperature, plasma potential, and mean ion energy vary inversely with pressure, but increase with CHF3 content in the mixture.

  3. Performance of concrete incorporating colloidal nano-silica

    NASA Astrophysics Data System (ADS)

    Zeidan, Mohamed Sabry

    Nanotechnology, as one of the most modern fields of science, has great market potential and economic impact. The need for research in the field of nanotechnology is continuously on the rise. During the last few decades, nanotechnology was developing rapidly into many fields of applied sciences, engineering and industrial applications, especially through studies of physics, chemistry, medicine and fundamental material science. These new developments may be attributed to the fact that material properties and performance can be significantly improved and controlled through nano-scale processes and nano-structures. This research program aims at 1) further understanding the behavior of cementitious materials when amended on the nano-scale level and 2) exploring the effect of this enhancement on the microstructure of cement matrix. This study may be considered as an important step towards better understanding the use of nano-silica in concrete. The main goal of the study is to investigate the effect of using colloidal nano-silica on properties of concrete, including mechanical properties, durability, transport properties, and microstructure. The experimental program that was conducted included a laboratory investigation of concrete mixtures in which nano-silica was added to cement or to a combination of cement and Class F fly ash. Various ratios of nano-silica were used in concrete mixtures to examine the extent and types of improvements that could be imparted to concrete. The conducted experimental program assessed these improvements in terms of reactivity, mechanical properties, and durability of the mixtures under investigation. Advanced testing techniques---including mercury intrusion porosimetry (MIP) and scanning electron microscopy (SEM)---were used to investigate the effect of nano-silica on the microstructure of the tested mixtures. In addition, the effect of nano-silica on the alkali-silica reaction (ASR) was examined using various techniques, including testing

  4. The Structure of Concrete Operational Thought.

    ERIC Educational Resources Information Center

    Tomlinson-Keasey, C.: And Others

    1979-01-01

    In a four-year longitudinal study of the development of concrete operational thought, children were administered tests assessing seriation; numeration; class inclusion; hierarchical classification; and conservation of mass, weight, and volume. Levels of seriation and numeration skills in kindergarten were powerful predictors of the acquisition of…

  5. Concrete sample point: 304 Concretion Facility

    SciTech Connect

    Rollison, M.D.

    1995-03-10

    This report contains information concerning the analysis of concretes for volatile organic compounds. Included are the raw data for these analysis and the quality control data, the standards data, and all of the accompanying chains-of-custody records and requests for special analysis.

  6. Performance of Waterless Concrete

    NASA Technical Reports Server (NTRS)

    Toutanji, Houssam; Evans, Steve; Grugel, Richard N.

    2010-01-01

    The development of permanent lunar bases is constrained by performance of construction materials and availability of in-situ resources. Concrete seems a suitable construction material for the lunar environment, but water, one of its major components, is an extremely scarce resource on the Moon. This study explores an alternative to hydraulic concrete by replacing the binding mix of concrete (cement and water) with sulfur. Sulfur is a volatile element on the lunar surface that can be extracted from lunar soils by heating. Sulfur concrete mixes were prepared to investigate the effect of extreme environmental conditions on the properties of sulfur concrete. A hypervelocity impact test was conducted, having as its target a 5-cm cubic sample of sulfur concrete. This item consisted of JSC-1 lunar regolith simulant (65%) and sulfur (35%). The sample was placed in the MSFC Impact Test Facility s Micro Light Gas Gun target chamber, and was struck by a 1-mm diameter (1.4e-03 g) aluminum projectile at 5.85 km/s. In addition, HZTERN code, provided by NASA was used to study the effectiveness of sulfur concrete when subjected to space radiation.

  7. Effects of lightweight fly ash aggregate properties on the behavior of lightweight concretes.

    PubMed

    Kockal, Niyazi Ugur; Ozturan, Turan

    2010-07-15

    Influence of different lightweight fly ash aggregates on the behavior of concrete mixtures was discussed. The performance characteristics of lightweight concretes (LWCs) and normalweight concrete (NWC) were investigated through compressive strength, modulus of elasticity and splitting tensile strength representing the mechanical behavior; through rapid chloride permeability representing the transport properties and through rapid freezing and thawing cycling representing the durability of concrete. In order to investigate the aggregate-cement paste interfacial transition zone (ITZ), SEM observations were performed. Regression and graphical analysis of the experimental data obtained were also performed. An increase in compressive strength was observed with the increase in oven-dry density. The ratios of splitting tensile strength to compressive strength of lightweight aggregate concretes were found to be similar to that of normalweight concrete. All the 28- and 56-day concrete specimens had a durability factor greater than 85 and 90, respectively, which met the requirement for freezing and thawing durability. PMID:20399557

  8. Biodecontamination of concrete

    SciTech Connect

    Hamilton, M.A.; Rogers, R.D.; Benson, J.

    1996-12-31

    A novel technology for biologically decontaminating concrete is being jointly developed by scientists at the Idaho National Engineering Laboratory (INEL) and British Nuclear Fuels plc (BNFL). The technology exploits a naturally occurring phenomenon referred to as microbially influenced degradation (MID) in which bacteria produce acids that dissolve the cement matrix of concrete. Most radionuclide contamination of concrete is fixed in the outer few mm of the concrete surface. By capturing and controlling this natural process, a biological method of removing the surface of concrete to depths up to several mm is being developed. Three types of bacteria are known to be important in MID of concrete: nitrifying bacteria that produce nitric acid, sulfur oxidizing bacteria that produce sulfuric acid, and certain heterotrophic bacteria that produce organic acids. An investigation of natural environments demonstrated with scanning electron microscopy the presence of bacteria on concrete surfaces of a variety of structures, such as bridges and dams, where corrosion is evident. Enumeration of sulfur oxidizing and nitrifying bacteria revealed their presence and activity on structures to varying degrees in different environments. Under ideal conditions, Thiobacillus thiooxidans, a sulfur oxidizing bacteria, attached to and colonized the surface of concrete specimens. Over 1mm depth of material from a 10 cm x 10 cm square surface was removed in 68 days in the Thiobacillus treated specimen compared to a sterile control. Laboratory and field demonstrations are currently being conducted using experimental chambers designed to be mounted directly to concrete surfaces where radionuclide contamination exists. Data is being obtained in order to determine actual rates of surface removal and limitations to the system. This information will be used to develop a full scale decontamination technology.

  9. Innovative reuse of concrete slurry waste from ready-mixed concrete plants in construction products.

    PubMed

    Xuan, Dongxing; Zhan, Baojian; Poon, Chi Sun; Zheng, Wei

    2016-07-15

    Concrete slurry waste (CSW) is generated from ready-mixed concrete plants during concrete production and is classified as a corrosive hazardous material. If it is disposed of at landfills, it would cause detrimental effects for our surrounding environment and ecosystems due to its high pH value as well as heavy metal contamination and accumulation. A new method in this study has been introduced to effectively reuse CSW in new construction products. In this method, the calcium-silicate rich CSW in the fresh state was considered as a cementitious paste as well as a CO2 capture medium. The experimental results showed that the pH values of the collected CSWs stored for 28 days ranged from 12.5 to 13.0 and a drastic decrease of pH value was detected after accelerated mineral carbonation. The theoretically calculated CO2 sequestration extent of CSWs was from 27.05% to 31.23%. The practical water to solid ratio in the fresh CSW varied from 0.76 to 1.12, which had a significant impact on the compressive strength of the mixture with CSWs. After subjecting to accelerated mineral carbonation, rapid initial strength development and lower drying shrinkage for the prepared concrete mixture were achieved. PMID:27016667

  10. Innovative reuse of concrete slurry waste from ready-mixed concrete plants in construction products.

    PubMed

    Xuan, Dongxing; Zhan, Baojian; Poon, Chi Sun; Zheng, Wei

    2016-07-15

    Concrete slurry waste (CSW) is generated from ready-mixed concrete plants during concrete production and is classified as a corrosive hazardous material. If it is disposed of at landfills, it would cause detrimental effects for our surrounding environment and ecosystems due to its high pH value as well as heavy metal contamination and accumulation. A new method in this study has been introduced to effectively reuse CSW in new construction products. In this method, the calcium-silicate rich CSW in the fresh state was considered as a cementitious paste as well as a CO2 capture medium. The experimental results showed that the pH values of the collected CSWs stored for 28 days ranged from 12.5 to 13.0 and a drastic decrease of pH value was detected after accelerated mineral carbonation. The theoretically calculated CO2 sequestration extent of CSWs was from 27.05% to 31.23%. The practical water to solid ratio in the fresh CSW varied from 0.76 to 1.12, which had a significant impact on the compressive strength of the mixture with CSWs. After subjecting to accelerated mineral carbonation, rapid initial strength development and lower drying shrinkage for the prepared concrete mixture were achieved.

  11. Concrete: Potential material for Space Station

    NASA Technical Reports Server (NTRS)

    Lin, T. D.

    1992-01-01

    To build a permanent orbiting space station in the next decade is NASA's most challenging and exciting undertaking. The space station will serve as a center for a vast number of scientific products. As a potential material for the space station, reinforced concrete was studied, which has many material and structural merits for the proposed space station. Its cost-effectiveness depends on the availability of lunar materials. With such materials, only 1 percent or less of the mass of a concrete space structure would have to be transported from earth.

  12. Compressive strength and hydration processes of concrete with recycled aggregates

    SciTech Connect

    Koenders, Eduardus A.B.; Pepe, Marco; Martinelli, Enzo

    2014-02-15

    This paper deals with the correlation between the time evolution of the degree of hydration and the compressive strength of Recycled Aggregate Concrete (RAC) for different water to cement ratios and initial moisture conditions of the Recycled Concrete Aggregates (RCAs). Particularly, the influence of such moisture conditions is investigated by monitoring the hydration process and determining the compressive strength development of fully dry or fully saturated recycled aggregates in four RAC mixtures. Hydration processes are monitored via temperature measurements in hardening concrete samples and the time evolution of the degree of hydration is determined through a 1D hydration and heat flow model. The effect of the initial moisture condition of RCAs employed in the considered concrete mixtures clearly emerges from this study. In fact, a novel conceptual method is proposed to predict the compressive strength of RAC-systems, from the initial mixture parameters and the hardening conditions. -- Highlights: •The concrete industry is more and more concerned with sustainability issues. •The use of recycled aggregates is a promising solution to enhance sustainability. •Recycled aggregates affect both hydration processes and compressive strength. •A fundamental approach is proposed to unveil the influence of recycled aggregates. •Some experimental comparisons are presented to validate the proposed approach.

  13. Recovery of MSWI and soil washing residues as concrete aggregates.

    PubMed

    Sorlini, Sabrina; Abbà, Alessandro; Collivignarelli, Carlo

    2011-02-01

    The aim of the present work was to study if municipal solid waste incinerator (MSWI) residues and aggregates derived from contaminated soil washing could be used as alternative aggregates for concrete production. Initially, chemical, physical and geometric characteristics (according to UNI EN 12620) of municipal solid waste incineration bottom ashes and some contaminated soils were evaluated; moreover, the pollutants release was evaluated by means of leaching tests. The results showed that the reuse of pre-treated MSWI bottom ash and washed soil is possible, either from technical or environmental point of view, while it is not possible for the raw wastes. Then, the natural aggregate was partially and totally replaced with these recycled aggregates for the production of concrete mixtures that were characterized by conventional mechanical and leaching tests. Good results were obtained using the same dosage of a high resistance cement (42.5R calcareous Portland cement instead of 32.5R); the concrete mixture containing 400 kg/m(3) of washed bottom ash and high resistance cement was classified as structural concrete (C25/30 class). Regarding the pollutants leaching, all concrete mixtures respected the limit values according to the Italian regulation. PMID:20537523

  14. Recovery of MSWI and soil washing residues as concrete aggregates.

    PubMed

    Sorlini, Sabrina; Abbà, Alessandro; Collivignarelli, Carlo

    2011-02-01

    The aim of the present work was to study if municipal solid waste incinerator (MSWI) residues and aggregates derived from contaminated soil washing could be used as alternative aggregates for concrete production. Initially, chemical, physical and geometric characteristics (according to UNI EN 12620) of municipal solid waste incineration bottom ashes and some contaminated soils were evaluated; moreover, the pollutants release was evaluated by means of leaching tests. The results showed that the reuse of pre-treated MSWI bottom ash and washed soil is possible, either from technical or environmental point of view, while it is not possible for the raw wastes. Then, the natural aggregate was partially and totally replaced with these recycled aggregates for the production of concrete mixtures that were characterized by conventional mechanical and leaching tests. Good results were obtained using the same dosage of a high resistance cement (42.5R calcareous Portland cement instead of 32.5R); the concrete mixture containing 400 kg/m(3) of washed bottom ash and high resistance cement was classified as structural concrete (C25/30 class). Regarding the pollutants leaching, all concrete mixtures respected the limit values according to the Italian regulation.

  15. Electrokenitic Corrosion Treatment of Concrete

    NASA Technical Reports Server (NTRS)

    Cardenas, Henry E (Inventor)

    2015-01-01

    A method and apparatus for strengthening cementitious concrete by placing a nanoparticle carrier liquid in contact with a first surface of a concrete section and inducing a current across the concrete section at sufficient magnitude and for sufficient time that nanoparticles in the nanoparticle carrier liquid migrate through a significant depth of the concrete section.

  16. Precast concrete pavements

    NASA Astrophysics Data System (ADS)

    Rollings, R. S.; Chou, Y. T.

    1981-11-01

    This report reviewed published literature on precast concrete pavements and found that precast concrete pavements have had some limited application in airfields, roads, and storage areas. This review of past experience and an analytical study of precast slabs concluded that existing design and construction techniques can be adapted for use with precast concrete pavements, but more work is needed to develop effective and easily constructed load transfer designs for slab joints. Precast concrete does not offer any advantage for conventional pavements due to its high cost and surface roughness, but it may find applications for special problems such as construction in adverse weather, subgrade settlement, temporary pavements that need to be relocated, and military operations.

  17. Strengthening lightweight concrete

    NASA Technical Reports Server (NTRS)

    Auskern, A.

    1972-01-01

    Polymer absorption by lightweight concretes to improve bonding between cement and aggregate and to increase strength of cement is discussed. Compressive strength of treated cement is compared with strength of untreated product. Process for producing polymers is described.

  18. An attempt to validate the ultra-accelerated microbar and the concrete performance test with the degree of AAR-induced damage observed in concrete structures

    SciTech Connect

    Leemann, Andreas; Merz, Christine

    2013-07-15

    There is little knowledge about the relation between AAR-induced damage observed in structures and the expansion potential obtained with accelerated tests. In this study, aggregates used in structures damaged by AAR were tested with the microbar test (MBT/AFNOR XP 18-594) and the concrete performance test (CPT/AFNOR P18-454). After the tests, the samples were examined using optical and scanning electron microscopy. Based on the results, the significance of the microbar test has to be examined very critically. The agreement of measured expansion, reacted rock types and the composition of the reaction products between the on-site concrete and the reproduced concrete subjected to the CPT clearly indicates that the reaction mechanisms in the structure and in the concrete performance test are comparable. As such, the concrete performance test seems to be an appropriate tool to test the potential reactivity of specific concrete mixtures.

  19. Shear Resistance between Concrete-Concrete Surfaces

    NASA Astrophysics Data System (ADS)

    Kovačovic, Marek

    2013-12-01

    The application of precast beams and cast-in-situ structural members cast at different times has been typical of bridges and buildings for many years. A load-bearing frame consists of a set of prestressed precast beams supported by columns and diaphragms joined with an additionally cast slab deck. This article is focused on the theoretical and experimental analyses of the shear resistance at an interface. The first part of the paper deals with the state-of-art knowledge of the composite behaviour of concrete-concrete structures and a comparison of the numerical methods introduced in the relevant standards. In the experimental part, a set of specimens with different interface treatments was tested until failure in order to predict the composite behaviour of coupled beams. The experimental part was compared to the numerical analysis performed by means of FEM basis nonlinear software.

  20. Blast impact behaviour of concrete with different fibre reinforcement

    NASA Astrophysics Data System (ADS)

    Drdlová, Martina; Čechmánek, René; Řídký, Radek

    2015-09-01

    The paper summarizes the results of the development of special concrete intended for the explosion resistance applications, with the emphasis on minimal secondary fragments formation at the explosion. The fine-grained concrete matrix has been reinforced by various types of short dispersed fibers (metallic, mineral and polymer) of different sizes and by their combination and the effect of the fibre reinforcement on the physico-mechanical properties and blast resistance was observed. The concrete prism specimens have been subjected to the determination of mechanical parameters (compressive and flexural strength at quasi-static load). The blast tests were conducted on the slab specimens prepared from selected mixtures. The material characteristics and explosion test data have been used for numerical investigation, which defined the optimal wall composition and dimensions of the concrete element which should resist the explosion defined by type, size, weight and placement of the blast. In the next step the test elements resistance was verified by real explosion test.

  1. Wooden concrete: High thermal efficiency using waste wood

    SciTech Connect

    Kosny, J.

    1994-09-01

    Wood concrete mixture of wood shavings, lime and cement is widely used in European building construction. In spite of many advantages, this material is almost unknown in the US. Eventual application of wooden concrete in building block production is discussed in this paper. Based on finite difference computer modeling, the thermal performance of several masonry wall systems and their components have been analyzed. The total wall system thermal performance for a typical single-story ranch house also has been determined. At present, typical experimental wall measurements and calculations do not include the effects of building envelope subsystems such as comers, window and door openings, and structural joints with roofs, floors, ceilings, and other walls. In masonry wall systems, these details may represent significant thermal bridges because of the highly conductive structural concrete. Many of the typical thermal bridges may be reduced by application of wood concrete elements.

  2. Engineering properties of inorganic polymer concretes (IPCs)

    SciTech Connect

    Sofi, M.; Deventer, J.S.J. van . E-mail: jannie@unimelb.edu.au; Mendis, P.A. . E-mail: pamendis@unimelb.edu.au; Lukey, G.C.

    2007-02-15

    This paper presents the engineering properties of inorganic polymer concretes (IPCs) with a compressive strength of 50 MPa. The study includes a determination of the modulus of elasticity, Poisson's ratio, compressive strength, and the splitting tensile strength and flexural strength of IPCs, formulated using three different sources of Class-F fly ash. Six IPC mix designs were adopted to evaluate the effects of the inclusion of coarse aggregates and granulated blast furnace slag into the mixes. A total of 90 cylindrical and 24 small beam specimens were investigated, and all tests were carried out pursuant to the relevant Australian Standards. Although some variability between the mixes was observed, the results show that, in most cases, the engineering properties of IPCs compare favorably to those predicted by the relevant Australian Standards for concrete mixtures.

  3. Method for increasing the rate of compressive strength gain in hardenable mixtures containing fly ash

    DOEpatents

    Liskowitz, J.W.; Wecharatana, M.; Jaturapitakkul, C.; Cerkanowicz, A.E.

    1997-10-28

    The present invention relates to concrete, mortar and other hardenable mixtures comprising cement and fly ash for use in construction. The invention provides a method for increasing the rate of strength gain of a hardenable mixture containing fly ash by exposing the fly ash to an aqueous slurry of calcium oxide (lime) prior to its incorporation into the hardenable mixture. The invention further relates to such hardenable mixtures, e.g., concrete and mortar, that contain fly ash pre-reacted with calcium oxide. In particular, the fly ash is added to a slurry of calcium oxide in water, prior to incorporating the fly ash in a hardenable mixture. The hardenable mixture may be concrete or mortar. In a specific embodiment, mortar containing fly ash treated by exposure to an aqueous lime slurry are prepared and tested for compressive strength at early time points. 2 figs.

  4. Method for increasing the rate of compressive strength gain in hardenable mixtures containing fly ash

    DOEpatents

    Liskowitz, John W.; Wecharatana, Methi; Jaturapitakkul, Chai; Cerkanowicz, deceased, Anthony E.

    1997-01-01

    The present invention relates to concrete, mortar and other hardenable mixtures comprising cement and fly ash for use in construction. The invention provides a method for increasing the rate of strength gain of a hardenable mixture containing fly ash by exposing the fly ash to an aqueous slurry of calcium oxide (lime) prior to its incorporation into the hardenable mixture. The invention further relates to such hardenable mixtures, e.g., concrete and mortar, that contain fly ash pre-reacted with calcium oxide. In particular, the fly ash is added to a slurry of calcium oxide in water, prior to incorporating the fly ash in a hardenable mixture. The hardenable mixture may be concrete or mortar. In a specific embodiment, mortar containing fly ash treated by exposure to an aqueous lime slurry are prepared and tested for compressive strength at early time points.

  5. Binary Effect of Fly Ash and Palm Oil Fuel Ash on Heat of Hydration Aerated Concrete

    PubMed Central

    Mehmannavaz, Taha; Ismail, Mohammad; Radin Sumadi, Salihuddin; Rafique Bhutta, Muhammad Aamer; Samadi, Mostafa

    2014-01-01

    The binary effect of pulverized fuel ash (PFA) and palm oil fuel ash (POFA) on heat of hydration of aerated concrete was studied. Three aerated concrete mixes were prepared, namely, concrete containing 100% ordinary Portland cement (control sample or Type I), binary concrete made from 50% POFA (Type II), and ternary concrete containing 30% POFA and 20% PFA (Type III). It is found that the temperature increases due to heat of hydration through all the concrete specimens especially in the control sample. However, the total temperature rises caused by the heat of hydration through both of the new binary and ternary concrete were significantly lower than the control sample. The obtained results reveal that the replacement of Portland cement with binary and ternary materials is beneficial, particularly for mass concrete where thermal cracking due to extreme heat rise is of great concern. PMID:24696646

  6. Binary effect of fly ash and palm oil fuel ash on heat of hydration aerated concrete.

    PubMed

    Mehmannavaz, Taha; Ismail, Mohammad; Radin Sumadi, Salihuddin; Rafique Bhutta, Muhammad Aamer; Samadi, Mostafa; Sajjadi, Seyed Mahdi

    2014-01-01

    The binary effect of pulverized fuel ash (PFA) and palm oil fuel ash (POFA) on heat of hydration of aerated concrete was studied. Three aerated concrete mixes were prepared, namely, concrete containing 100% ordinary Portland cement (control sample or Type I), binary concrete made from 50% POFA (Type II), and ternary concrete containing 30% POFA and 20% PFA (Type III). It is found that the temperature increases due to heat of hydration through all the concrete specimens especially in the control sample. However, the total temperature rises caused by the heat of hydration through both of the new binary and ternary concrete were significantly lower than the control sample. The obtained results reveal that the replacement of Portland cement with binary and ternary materials is beneficial, particularly for mass concrete where thermal cracking due to extreme heat rise is of great concern.

  7. Binary effect of fly ash and palm oil fuel ash on heat of hydration aerated concrete.

    PubMed

    Mehmannavaz, Taha; Ismail, Mohammad; Radin Sumadi, Salihuddin; Rafique Bhutta, Muhammad Aamer; Samadi, Mostafa; Sajjadi, Seyed Mahdi

    2014-01-01

    The binary effect of pulverized fuel ash (PFA) and palm oil fuel ash (POFA) on heat of hydration of aerated concrete was studied. Three aerated concrete mixes were prepared, namely, concrete containing 100% ordinary Portland cement (control sample or Type I), binary concrete made from 50% POFA (Type II), and ternary concrete containing 30% POFA and 20% PFA (Type III). It is found that the temperature increases due to heat of hydration through all the concrete specimens especially in the control sample. However, the total temperature rises caused by the heat of hydration through both of the new binary and ternary concrete were significantly lower than the control sample. The obtained results reveal that the replacement of Portland cement with binary and ternary materials is beneficial, particularly for mass concrete where thermal cracking due to extreme heat rise is of great concern. PMID:24696646

  8. A new test procedure for biogenic sulfuric acid corrosion of concrete

    PubMed

    Vincke; Verstichel; Monteny; Verstraete

    1999-01-01

    A new test method is described for biogenic sulfuric acid corrosion of concrete, more specifically in sewer conditions. The aim of the new test method is the development of an accelerated and reproducible procedure for monitoring the resistance of different types of concrete with regard to biogenic sulfuric acid corrosion. This experimental procedure reflects worst case conditions by providing besides H2S, also an enrichment of thiobacilli and biologically produced sulfur. By simulating the cyclic processes occurring in sewer pipes, significant differences between concrete mixtures could be detected after 51 days. Concrete modified by a styrene-acrylic ester polymer demonstrated a higher resistance against biogenic sulfuric acid attack. PMID:11068828

  9. A new test procedure for biogenic sulfuric acid corrosion of concrete

    PubMed

    Vincke; Verstichel; Monteny; Verstraete

    1999-01-01

    A new test method is described for biogenic sulfuric acid corrosion of concrete, more specifically in sewer conditions. The aim of the new test method is the development of an accelerated and reproducible procedure for monitoring the resistance of different types of concrete with regard to biogenic sulfuric acid corrosion. This experimental procedure reflects worst case conditions by providing besides H2S, also an enrichment of thiobacilli and biologically produced sulfur. By simulating the cyclic processes occurring in sewer pipes, significant differences between concrete mixtures could be detected after 51 days. Concrete modified by a styrene-acrylic ester polymer demonstrated a higher resistance against biogenic sulfuric acid attack.

  10. Proportioning and performance evaluation of self-consolidating concrete

    NASA Astrophysics Data System (ADS)

    Wang, Xuhao

    A well-proportioned self-consolidating concrete (SCC) mixture can be achieved by controlling the aggregate system, paste quality, and paste quantity. The work presented in this dissertation involves an effort to study and improve particle packing of the concrete system and reduce the paste quantity while maintaining concrete quality and performance. This dissertation is composed of four papers resulting from the study: (1) Assessing Particle Packing Based Self-Consolidating Concrete Mix Design; (2) Using Paste-To-Voids Volume Ratio to Evaluate the Performance of Self-Consolidating Concrete Mixtures; (3) Image Analysis Applications on Assessing Static Stability and Flowability of Self-Consolidating Concrete, and (4) Using Ultrasonic Wave Propagation to Monitor Stiffening Process of Self-Consolidating Concrete. Tests were conducted on a large matrix of SCC mixtures that were designed for cast-in-place bridge construction. The mixtures were made with different aggregate types, sizes, and different cementitious materials. In Paper 1, a modified particle-packing based mix design method, originally proposed by Brouwers (2005), was applied to the design of self-consolidating concrete (SCC) mixs. Using this method, a large matrix of SCC mixes was designed to have a particle distribution modulus (q) ranging from 0.23 to 0.29. Fresh properties (such as flowability, passing ability, segregation resistance, yield stress, viscosity, set time and formwork pressure) and hardened properties (such as compressive strength, surface resistance, shrinkage, and air structure) of these concrete mixes were experimentally evaluated. In Paper 2, a concept that is based on paste-to-voids volume ratio (Vpaste/Vvoids) was employed to assess the performance of SCC mixtures. The relationship between excess paste theory and Vpaste/Vvoids was investigated. The workability, flow properties, compressive strength, shrinkage, and surface resistivity of SCC mixtures were determined at various ages

  11. Properties of concrete containing scrap-tire rubber--an overview.

    PubMed

    Siddique, Rafat; Naik, Tarun R

    2004-01-01

    Solid waste management is one of the major environmental concerns in the United States. Over 5 billion tons of non-hazardous solid waste materials are generated in USA each year. Of these, more than 270 million scrap-tires (approximately 3.6 million tons) are generated each year. In addition to this, about 300 million scrap-tires have been stockpiled. Several studies have been carried out to reuse scrap-tires in a variety of rubber and plastic products, incineration for production of electricity, or as fuel for cement kilns, as well as in asphalt concrete. Studies show that workable rubberized concrete mixtures can be made with scrap-tire rubber. This paper presents an overview of some of the research published regarding the use of scrap-tires in portland cement concrete. The benefits of using magnesium oxychloride cement as a binder for rubberized concrete mixtures are also presented. The paper details the likely uses of rubberized concrete.

  12. Reclamation chain of waste concrete: A case study of Shanghai.

    PubMed

    Xiao, Jianzhuang; Ma, Zhiming; Ding, Tao

    2016-02-01

    A mass of construction and demolition (C&D) waste are generated in Shanghai every year, and it has become a serious environment problem. Reclaiming the waste concrete to produce recycled aggregate (RA) and recycled aggregate concrete (RAC) is an effective method to reduce the C&D waste. This paper develops a reclamation chain of waste concrete based on the researches and practices in Shanghai. C&D waste management, waste concrete disposition, RA production and RAC preparation are discussed respectively. In addition, technical suggestions are also given according to the findings in practical engineering, which aims to optimize the reclamation chain. The results show that the properties of RA and RAC can well meet the requirement of design and practical application through a series of technical measures. The reclamation chain of waste concrete is necessary and appropriate for Shanghai, which provides more opportunities for the wider application of RA and RAC, and it shows a favorable environmental benefit. PMID:26452425

  13. Reclamation chain of waste concrete: A case study of Shanghai.

    PubMed

    Xiao, Jianzhuang; Ma, Zhiming; Ding, Tao

    2016-02-01

    A mass of construction and demolition (C&D) waste are generated in Shanghai every year, and it has become a serious environment problem. Reclaiming the waste concrete to produce recycled aggregate (RA) and recycled aggregate concrete (RAC) is an effective method to reduce the C&D waste. This paper develops a reclamation chain of waste concrete based on the researches and practices in Shanghai. C&D waste management, waste concrete disposition, RA production and RAC preparation are discussed respectively. In addition, technical suggestions are also given according to the findings in practical engineering, which aims to optimize the reclamation chain. The results show that the properties of RA and RAC can well meet the requirement of design and practical application through a series of technical measures. The reclamation chain of waste concrete is necessary and appropriate for Shanghai, which provides more opportunities for the wider application of RA and RAC, and it shows a favorable environmental benefit.

  14. Discrete Velocity Models for Mixtures Without Nonphysical Collision Invariants

    NASA Astrophysics Data System (ADS)

    Bernhoff, Niclas; Vinerean, Mirela

    2016-09-01

    An important aspect of constructing discrete velocity models (DVMs) for the Boltzmann equation is to obtain the right number of collision invariants. It is a well-known fact that DVMs can also have extra collision invariants, so called spurious collision invariants, in plus to the physical ones. A DVM with only physical collision invariants, and so without spurious ones, is called normal. For binary mixtures also the concept of supernormal DVMs was introduced, meaning that in addition to the DVM being normal, the restriction of the DVM to any single species also is normal. Here we introduce generalizations of this concept to DVMs for multicomponent mixtures. We also present some general algorithms for constructing such models and give some concrete examples of such constructions. One of our main results is that for any given number of species, and any given rational mass ratios we can construct a supernormal DVM. The DVMs are constructed in such a way that for half-space problems, as the Milne and Kramers problems, but also nonlinear ones, we obtain similar structures as for the classical discrete Boltzmann equation for one species, and therefore we can apply obtained results for the classical Boltzmann equation.

  15. Discrete Velocity Models for Mixtures Without Nonphysical Collision Invariants

    NASA Astrophysics Data System (ADS)

    Bernhoff, Niclas; Vinerean, Mirela

    2016-10-01

    An important aspect of constructing discrete velocity models (DVMs) for the Boltzmann equation is to obtain the right number of collision invariants. It is a well-known fact that DVMs can also have extra collision invariants, so called spurious collision invariants, in plus to the physical ones. A DVM with only physical collision invariants, and so without spurious ones, is called normal. For binary mixtures also the concept of supernormal DVMs was introduced, meaning that in addition to the DVM being normal, the restriction of the DVM to any single species also is normal. Here we introduce generalizations of this concept to DVMs for multicomponent mixtures. We also present some general algorithms for constructing such models and give some concrete examples of such constructions. One of our main results is that for any given number of species, and any given rational mass ratios we can construct a supernormal DVM. The DVMs are constructed in such a way that for half-space problems, as the Milne and Kramers problems, but also nonlinear ones, we obtain similar structures as for the classical discrete Boltzmann equation for one species, and therefore we can apply obtained results for the classical Boltzmann equation.

  16. Resin systems for producing polymer concrete

    SciTech Connect

    Kukacka, L.E.

    1988-09-01

    When plastics are combined with mixtures of inorganic materials, high-strength, durable, fast-setting composites are produced. These materials are used in structural engineering and other applications, and as a result of the many commercial successes that have been achieved, considerable research and development work is in progress throughout the world. One family of polymer-based composites receiving considerable attention is called polymer concrete. Work in this area is directed toward developing new high-strength durable materials by combining cement and concrete technology with that of polymer chemistry. The purpose of this paper is to discuss the types of resins that can be used to form polymer concretes. Resin selection is normally based upon the desired properties for the composite and cost. However, the physical and chemical properties of the resins before and during curing are also important, particularly for field-applied materials. Currently, for normal temperature (0/degree/ to 30/degree/C) applications, epoxy resins, vinyl monomers such as polyester-styrene, methylmethacrylate, furfuryl alcohol, furan derivatives, urethane, and styrene, are being used. Styrene-trimethylolpropane trimethacrylate (TMPTMA) mixtures and styrene-acrylamide-TMPTMA mixtures yield composites with excellent hydrothermal stability at temperatures up to 150/degree/ and 250/degree/C, respectively, and organosiloxane resins have been successfully tested at 300/degree/C. Of equal importance is the selection of the composition of the inorganic phase of the composite, since chemical interactions between the two phases can significantly enhance the final properties. Further work to elucidate the mechanisms of these interactions is needed. 6 refs.

  17. Generation of sub-ppb level vapor phase mixtures of biogenic volatile organic compounds from liquid phase standards and stepwise characterization of their volatilization properties by thermal desorption-gas chromatography-mass spectrometry.

    PubMed

    Iqbal, Mohammad Asif; Kim, Ki-Hyun

    2014-12-19

    In the analysis of biogenic volatile organic compounds (BVOCs) in ambient air, preparation of a sub-ppb level standard is an important factor. This task is very challenging as most BVOCs (e.g., monoterpenes) are highly volatile and reactive in nature. As a means to produce sub-ppb gaseous standards for BVOCs, we investigated the dynamic headspace (HS) extraction technique through which their vapors are generated from a liquid standard (mixture of 10 BVOCs: (1) α-pinene, (2) β-pinene, (3) 3-carene, (4) myrcene, (5) α-phellandrene, (6) α-terpinene, (7) R-limonene, (8) γ-terpinene, (9) p-cymene, and (10) Camphene) spiked into a chamber-style impinger. The quantification of BVOCs was made by collection on multiple-bed sorbent tubes (STs) and subsequent analysis by thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS). Using this approach, sub-ppb level mixtures of gaseous BVOCs were generated at different sweep cycles. The mean concentrations of 10 BVOCs generated from the most stable conditions (i.e., in the third sweep cycle) varied in the range of 0.37±0.05 to 7.27±0.86ppb depending on the initial concentration of liquid standard spiked into the system. The reproducibility of the gaseous BVOCs generated as mixture standards, if expressed in terms of relative standard error using the concentration datasets acquired under stable conditions, ranged from 1.64 (α-phellandrene) to 9.67% (R-limonene).

  18. 26. Evening view of concrete mixing plant, concrete placement tower, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    26. Evening view of concrete mixing plant, concrete placement tower, cableway tower, power line and derrick. Photographer unknown, 1927. Source: MWD. - Waddell Dam, On Agua Fria River, 35 miles northwest of Phoenix, Phoenix, Maricopa County, AZ

  19. 10. CONCRETE BRIDGE, REINFORCED BEAM TYPE ON CONCRETE, SOUTH CAROLINA ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    10. CONCRETE BRIDGE, REINFORCED BEAM TYPE ON CONCRETE, SOUTH CAROLINA STATE HIGHWAY DEPARTMENT, COLUMBIA, SOUTH CAROLINA (photocopy of drawing) - Salkehatchie Bridge, State Route No. 64 spanning Salkehatchie River, Barnwell, Barnwell County, SC

  20. What is under the hump? Mass spectrometry based analysis of complex mixtures in processed food--lessons from the characterisation of black tea thearubigins, coffee melanoidines and caramel.

    PubMed

    Kuhnert, Nikolai; Dairpoosh, Farnoosh; Yassin, Ghada; Golon, Agnieszka; Jaiswal, Rakesh

    2013-08-01

    In this contribution we review our work on the characterisation of processed food. We review novel methods and analysis strategies developed to account for the composition of extraordinarily complex materials such as black tea thearubigins, coffee melanoidines and thermally treated carbohydrates. Our methods are mainly based on modern mass spectrometry and are introduced and critically discussed. A series of novel previously unpublished data interpretation strategies are presented as well. Finally an evaluation of the insight obtained in the composition of selected processed foods is given discussing potential consequences for assessing beneficial and adverse health effects of processed food.

  1. Mechanical Properties and Durability of "Waterless Concrete"

    NASA Technical Reports Server (NTRS)

    Toutanji, Houssam; Grugel, Richard N.

    2008-01-01

    Waterless concrete consists of molten elementary sulfur and aggregate. The aggregates in lunar environment will be lunar rocks and soil. Sulfur is present on the Moon in Troilite soil (FeS) and by oxidation soil iron and sulfur can be produced. Iron can be used to reinforce the sulfur concrete. Sulfur concrete specimens were cycled between liquid nitrogen (approximately 191 C) and room temperature (approximately 21 C) to simulate exposure to a lunar environment. Cycled and control specimens were subsequently tested in compression at room temperatures (approximately 21 C) and approximately 101 C. Test results showed that due to temperature cycling, compressive strength of cycled specimens was 20% of those non-cycled. Microscopic examination of the fracture surfaces from the cycled samples showed clear de-bonding of the sulfur from the aggregate material whereas it was seen well bonded in those non-cycled. This reduction in strength can be attributed to the large differences in thermal coefficients of expansion of the materials constituting the concrete which promoted cracking. Similar sulfur concrete mixtures were strengthened with short and long glass fibers. The glass fibers from lunar regolith simulant was melted in a 25 cc Pt-Rh crucible in a Sybron Thermoline high temperature MoSi2 furnace at melting temperatures of 1450 to 1600 C for times of 30 min to 1 hour. Glass fibers were cast from the melt into graphite crucibles and were annealed for a couple of hours at 600 C. Glass fibers and small rods were pulled from the melt. The glass melt wets the ceramic rod and long continuous glass fibers were easily hand drawn. The glass fibers were immediately coated with a protective polymer to maintain the mechanical strength. The glass fibers were used to reinforce sulfur concrete plated to improve the flexural strength of the sulfur concrete. Prisms beams strengthened with glass fibers were tested in 4-point bending test. Beams strengthened with glass fiber showed to

  2. Comminution and sizing processes of concrete block waste as recycled aggregates.

    PubMed

    Gomes, P C C; Ulsen, C; Pereira, F A; Quattrone, M; Angulo, S C

    2015-11-01

    Due to the environmental impact of construction and demolition waste (CDW), recycling is mandatory. It is also important that recycled concrete aggregates (RCA) are used in concrete to meet market demands. In the literature, the influence of RCAs on concrete has been investigated, but very limited studies have been conducted on how the origin of concrete waste and comminution processes influence RCA characteristics. This paper aims to investigate the influence of three different comminution and sizing processes (simple screening, crushing and grinding) on the composition, shape and porosity characteristics of RCA obtained from concrete block waste. Crushing and grinding implies a reduction of RCA porosity. However, due to the presence of coarse quartz rounded river pebbles in the original concrete block mixtures, the shape characteristics deteriorated. A large amount of powder (<0.15 mm) without detectable anhydrous cement was also generated. PMID:26168872

  3. Comminution and sizing processes of concrete block waste as recycled aggregates.

    PubMed

    Gomes, P C C; Ulsen, C; Pereira, F A; Quattrone, M; Angulo, S C

    2015-11-01

    Due to the environmental impact of construction and demolition waste (CDW), recycling is mandatory. It is also important that recycled concrete aggregates (RCA) are used in concrete to meet market demands. In the literature, the influence of RCAs on concrete has been investigated, but very limited studies have been conducted on how the origin of concrete waste and comminution processes influence RCA characteristics. This paper aims to investigate the influence of three different comminution and sizing processes (simple screening, crushing and grinding) on the composition, shape and porosity characteristics of RCA obtained from concrete block waste. Crushing and grinding implies a reduction of RCA porosity. However, due to the presence of coarse quartz rounded river pebbles in the original concrete block mixtures, the shape characteristics deteriorated. A large amount of powder (<0.15 mm) without detectable anhydrous cement was also generated.

  4. Effect of monomer composition on the properties of high temperature polymer concretes

    SciTech Connect

    Zeldin, A.; Kukacka, L.E.; Carciello, N.

    1980-01-01

    The effects of organic monomer composition on the thermomechanical properties of polymer concrete (PC) containing sand-cement mixtures as an agregate filler were investigated. The effects of various monomer mixtures on compressive strength and hydrolytic stability are discussed. Composites were fabricated in the same way as ordinary concrete, with monomer solutions of various compositions and concentrations used to bind the sand-cement mixture. The compressive strengths of th composites before and after exposure to air and to brine solutions at 240/sup 0/C are discussed.

  5. Electrokinetic decontamination of concrete

    SciTech Connect

    Lomasney, H.

    1995-10-01

    The U.S. Department of Energy has assigned a priority to the advancement of technology for decontaminating concrete surfaces which have become contaminated with radionuclides, heavy metals, and toxic organics. This agency is responsible for decontamination and decommissioning of thousands of buildings. Electrokinetic extraction is one of the several innovative technologies which emerged in response to this initiative. This technique utilizes an electropotential gradient and the subsequent electrical transport mechanism to cause the controlled movement of ionics species, whereby the contaminants exit the recesses deep within the concrete. This report discusses the technology and use at the Oak Ridge k-25 plant.

  6. High temperature chemically resistant polymer concrete

    DOEpatents

    Sugama, T.; Kukacka, L.E.

    High temperature chemically resistant, non-aqueous polymer concrete composites consist of about 12 to 20% by weight of a water-insoluble polymer binder. The binder is polymerized in situ from a liquid vinyl-type monomer or mixture of vinyl containing monomers such as triallylcyanurate, styrene, acrylonitrile, acrylamide, methacrylamide, methyl-methacrylate, trimethylolpropane trimethacrylate and divinyl benzene. About 5 to 40% by weight of a reactive inorganic filler selected from the group consisting of tricalcium silicate and dicalcium silicate and mixtures containing less than 2% free lime, and about 48 to 83% by weight of silica sand/ and a free radical initiator such as di-tert-butyl peroxide, azobisisobutyronitrile, benzoyl peroxide, lauryl peroxide, other orgaic peroxides and combinations to initiate polymerization of the monomer in the presence of the inorganic filers are used.

  7. Use of comprehensive two-dimensional gas chromatography/time-of-flight mass spectrometry for the characterization of biodegradation and unresolved complex mixtures in petroleum

    NASA Astrophysics Data System (ADS)

    Tran, Tin C.; Logan, Graham A.; Grosjean, Emmanuelle; Ryan, Danielle; Marriott, Philip J.

    2010-11-01

    A comprehensive two-dimensional gas chromatography/time-of-flight mass spectrometry (GC × GC/TOFMS) method has been developed for separation of a series of petroleum samples using a polar/non-polar column set configuration. Groups of oils were selected to provide samples from the same oil family to assist in comparison of compositional changes during biodegradation. The groups also represented different sources and ages to allow an assessment of the application of GC × GC for the differentiation of oil source, as well as fluid history. The increased resolution and separation afforded by the GC × GC technique provides more complete compositional information on complex biodegraded oil samples than one-dimensional GC, and improves the ability to study biodegradation trends. Among the components identified, it is proposed that alkyl-decahydronaphthalenes constitute a significant contribution to the UCM.

  8. Material Properies of Intermediate Materials between Concrete and Gravelly Soil

    NASA Astrophysics Data System (ADS)

    Uchimura, Taro; Kuramochi, Yuko; Thai, Bach Thuan

    Compaction and strength properties of cement-mixed well-graded gravel are studied. Such materials can also be considered as a kind of concrete materials which has much lower cement contents than usual. New concepts on material properties related to their mixture ratio of cement, gravel (aggregate) and water, as well as their compaction density, are proposed, unifying the concepts of geotechnical engineering and concrete engineering. For materials with higher cement contents, the compaction curve becomes flat, with lower maximum compaction density, and higher optimum water contents. The triaxial compressive strength are clearly affected by the dry density, as well as the cement contents.

  9. Use of selected waste materials in concrete mixes

    SciTech Connect

    Batayneh, Malek Marie, Iqbal; Asi, Ibrahim

    2007-07-01

    A modern lifestyle, alongside the advancement of technology has led to an increase in the amount and type of waste being generated, leading to a waste disposal crisis. This study tackles the problem of the waste that is generated from construction fields, such as demolished concrete, glass, and plastic. In order to dispose of or at least reduce the accumulation of certain kinds of waste, it has been suggested to reuse some of these waste materials to substitute a percentage of the primary materials used in the ordinary portland cement concrete (OPC). The waste materials considered to be recycled in this study consist of glass, plastics, and demolished concrete. Such recycling not only helps conserve natural resources, but also helps solve a growing waste disposal crisis. Ground plastics and glass were used to replace up to 20% of fine aggregates in concrete mixes, while crushed concrete was used to replace up to 20% of coarse aggregates. To evaluate these replacements on the properties of the OPC mixes, a number of laboratory tests were carried out. These tests included workability, unit weight, compressive strength, flexural strength, and indirect tensile strength (splitting). The main findings of this investigation revealed that the three types of waste materials could be reused successfully as partial substitutes for sand or coarse aggregates in concrete mixtures.

  10. Heidrun concrete TLP: Update

    SciTech Connect

    Munkejord, T.

    1995-10-01

    This paper gives a summary of the Heidrun substructure including tethers and foundations. The focus will although be on the concrete substructure. The Heidrun Field is located in 345 m water depth in the northern part of the Haltenbanken area, approximately 100N miles from the west coast of mid-Norway. The field is developed by means of a concrete Tension Leg Platform (TLP) by Conoco Norway Inc. The TLP will be moored by 16 steel tethers, arranged in groups of four per corner, which secure the substructure (hull) to the concrete foundations. A general view of the TLP is shown. The Heidrun TLP will be the northern most located platform in the North Sea when installed at Haltenbanken in 1995. Norwegian Contractors a.s (NC) is undertaking the Engineering, Procurement, Construction and Installation (EPCI) contract for the Heidrun TLP substructure. This comprises the complete delivery of the hull with two module support beams (MSB), including all mechanical outfitting. Furthermore, NC will perform all marine operations related to the substructure. For the concrete foundations NC has performed the detailed engineering work and has been responsible for the two to field and installation of the foundations.

  11. High temperature polymer concrete

    DOEpatents

    Fontana, J.J.; Reams, W.

    1984-05-29

    This invention is concerned with a polymer concrete composition, which is a two-component composition useful with many bases including metal. Component A, the aggregate composition, is broadly composed of silica, silica flour, portland cement, and acrylamide, whereas Component B, which is primarily vinyl and acrylyl reactive monomers, is a liquid system.

  12. Electroosmotic decontamination of concrete

    SciTech Connect

    Bostick, W.D.; Bush, S.A.; Marsh, G.C.; Henson, H.M.; Box, W.D.; Morgan, I.L.

    1993-03-01

    A method is described for the electroosmotic decontamination of concrete surfaces, in which an electrical field is used to induce migration of ionic contaminants from porous concrete into an electrolyte solution that may be disposed of as a low-level liquid radioactive waste (LLRW); alternately, the contaminants from the solution can be sorbed onto anion exchange media in order to prevent contaminant buildup in the solution and to minimize the amount of LLRW generated. We have confirmed the removal of uranium (and infer the removal of {sup 99}Tc) from previously contaminated concrete surfaces. In a typical experimental configuration, a stainless steel mesh is placed in an electrolyte solution contained within a diked cell to serve as the negative electrode (cathode) and contaminant collection medium, respectively, and an existing metal penetration (e.g., piping, conduit, or rebar reinforcement within the concrete surface) serves as the positive electrode (anode) to complete the cell. Typically we have achieved 70 to >90% reductions in surface activity by applying <400 V and <1 A for 1--3 h (energy consumption of 0.4--12 kWh/ft{sup 2}).

  13. Active-site peptide "fingerprinting" of glycosidases in complex mixtures by mass spectrometry. Discovery of a novel retaining beta-1,4-glycanase in Cellulomonas fimi.

    PubMed

    Hekmat, Omid; Kim, Young-Wan; Williams, Spencer J; He, Shouming; Withers, Stephen G

    2005-10-21

    New proteomics methods are required for targeting and identification of subsets of a proteome in an activity-based fashion. Here, we report the first gel-free, mass spectrometry-based strategy for mechanism-based profiling of retaining beta-endoglycosidases in complex proteomes. Using a biotinylated, cleavable 2-deoxy-2-fluoroxylobioside inactivator, we have isolated and identified the active-site peptides of target retaining beta-1,4-glycanases in systems of increasing complexity: pure enzymes, artificial proteomes, and the secreted proteome of the aerobic mesophilic soil bacterium Cellulomonas fimi. The active-site peptide of a new C. fimi beta-1,4-glycanase was identified in this manner, and the peptide sequence, which includes the catalytic nucleophile, is highly conserved among glycosidase family 10 members. The glycanase gene (GenBank accession number DQ146941) was cloned using inverse PCR techniques, and the protein was found to comprise a catalytic domain that shares approximately 70% sequence identity with those of xylanases from Streptomyces sp. and a family 2b carbohydrate-binding module. The new glycanase hydrolyzes natural and artificial xylo-configured substrates more efficiently than their cello-configured counterparts. It has a pH dependence very similar to that of known C. fimi retaining glycanases. PMID:16085650

  14. Determination of polycyclic aromatic hydrocarbons in fractions in asphalt mixtures using liquid chromatography coupled to mass spectrometry with atmospheric pressure chemical ionization.

    PubMed

    Nascimento, Paulo Cicero; Gobo, Luciana Assis; Bohrer, Denise; Carvalho, Leandro Machado; Cravo, Margareth Coutinho; Leite, Leni Figueiredo Mathias

    2015-07-01

    An analytical method using liquid chromatography coupled to mass spectrometry with atmospheric pressure chemical ionization for the determination of polycyclic aromatic hydrocarbons in asphalt fractions has been developed. The 14 compounds determined, characterized by having two or more condensed aromatic rings, are expected to be present in asphalt and are considered carcinogenic and mutagenic. The parameters of the atmospheric pressure chemical ionization interface were optimized to obtain the highest possible sensitivity for all of the compounds. The limits of detection ranged from 0.5 to 346.5 μg/L and the limits of quantification ranged from 1.7 to 1550 μg/L. The method was validated against a diesel particulate extract standard reference material (NIST SRM 1975), and the obtained concentrations agreed with the certified values. The method was applied to asphalt samples after its fractionation according to ASTM D4124 and the method of Green. The concentrations of the seven polycyclic aromatic hydrocarbons quantified in the sample ranged from 0.86 mg/kg for benzo[ghi]perylene to 98.32 mg/kg for fluorene. PMID:25885756

  15. Determination of polycyclic aromatic hydrocarbons in fractions in asphalt mixtures using liquid chromatography coupled to mass spectrometry with atmospheric pressure chemical ionization.

    PubMed

    Nascimento, Paulo Cicero; Gobo, Luciana Assis; Bohrer, Denise; Carvalho, Leandro Machado; Cravo, Margareth Coutinho; Leite, Leni Figueiredo Mathias

    2015-07-01

    An analytical method using liquid chromatography coupled to mass spectrometry with atmospheric pressure chemical ionization for the determination of polycyclic aromatic hydrocarbons in asphalt fractions has been developed. The 14 compounds determined, characterized by having two or more condensed aromatic rings, are expected to be present in asphalt and are considered carcinogenic and mutagenic. The parameters of the atmospheric pressure chemical ionization interface were optimized to obtain the highest possible sensitivity for all of the compounds. The limits of detection ranged from 0.5 to 346.5 μg/L and the limits of quantification ranged from 1.7 to 1550 μg/L. The method was validated against a diesel particulate extract standard reference material (NIST SRM 1975), and the obtained concentrations agreed with the certified values. The method was applied to asphalt samples after its fractionation according to ASTM D4124 and the method of Green. The concentrations of the seven polycyclic aromatic hydrocarbons quantified in the sample ranged from 0.86 mg/kg for benzo[ghi]perylene to 98.32 mg/kg for fluorene.

  16. Determination of oxygen and nitrogen derivatives of polycyclic aromatic hydrocarbons in fractions of asphalt mixtures using liquid chromatography coupled to mass spectrometry with atmospheric pressure chemical ionization.

    PubMed

    Nascimento, Paulo Cicero; Gobo, Luciana Assis; Bohrer, Denise; Carvalho, Leandro Machado; Cravo, Margareth Coutinho; Leite, Leni Figueiredo Mathias

    2015-12-01

    Liquid chromatography coupled to mass spectrometry with atmospheric pressure chemical ionization was used for the determination of polycyclic aromatic hydrocarbon derivatives, the oxygenated polycyclic aromatic hydrocarbons and nitrated polycyclic aromatic hydrocarbons, formed in asphalt fractions. Two different methods have been developed for the determination of five oxygenated and seven nitrated polycyclic aromatic hydrocarbons that are characterized by having two or more condensed aromatic rings and present mutagenic and carcinogenic properties. The parameters of the atmospheric pressure chemical ionization interface were optimized to obtain the highest possible sensitivity for all compounds. The detection limits of the methods ranged from 0.1 to 57.3 μg/L for nitrated and from 0.1 to 6.6 μg/L for oxygenated derivatives. The limits of quantification were in the range of 4.6-191 μg/L for nitrated and 0.3-8.9 μg/L for oxygenated derivatives. The methods were validated against a diesel particulate extract standard reference material (National Institute of Standards and Technology SRM 1975), and the obtained concentrations (two nitrated derivatives) agreed with the certified values. The methods were applied in the analysis of asphalt samples after their fractionation into asphaltenes and maltenes, according to American Society for Testing and Material D4124, where the maltenic fraction was further separated into its basic, acidic, and neutral parts following the method of Green. Only two nitrated derivatives were found in the asphalt sample, quinoline and 2-nitrofluorene, with concentrations of 9.26 and 2146 mg/kg, respectively, whereas no oxygenated derivatives were detected. PMID:26446274

  17. Determination of oxygen and nitrogen derivatives of polycyclic aromatic hydrocarbons in fractions of asphalt mixtures using liquid chromatography coupled to mass spectrometry with atmospheric pressure chemical ionization.

    PubMed

    Nascimento, Paulo Cicero; Gobo, Luciana Assis; Bohrer, Denise; Carvalho, Leandro Machado; Cravo, Margareth Coutinho; Leite, Leni Figueiredo Mathias

    2015-12-01

    Liquid chromatography coupled to mass spectrometry with atmospheric pressure chemical ionization was used for the determination of polycyclic aromatic hydrocarbon derivatives, the oxygenated polycyclic aromatic hydrocarbons and nitrated polycyclic aromatic hydrocarbons, formed in asphalt fractions. Two different methods have been developed for the determination of five oxygenated and seven nitrated polycyclic aromatic hydrocarbons that are characterized by having two or more condensed aromatic rings and present mutagenic and carcinogenic properties. The parameters of the atmospheric pressure chemical ionization interface were optimized to obtain the highest possible sensitivity for all compounds. The detection limits of the methods ranged from 0.1 to 57.3 μg/L for nitrated and from 0.1 to 6.6 μg/L for oxygenated derivatives. The limits of quantification were in the range of 4.6-191 μg/L for nitrated and 0.3-8.9 μg/L for oxygenated derivatives. The methods were validated against a diesel particulate extract standard reference material (National Institute of Standards and Technology SRM 1975), and the obtained concentrations (two nitrated derivatives) agreed with the certified values. The methods were applied in the analysis of asphalt samples after their fractionation into asphaltenes and maltenes, according to American Society for Testing and Material D4124, where the maltenic fraction was further separated into its basic, acidic, and neutral parts following the method of Green. Only two nitrated derivatives were found in the asphalt sample, quinoline and 2-nitrofluorene, with concentrations of 9.26 and 2146 mg/kg, respectively, whereas no oxygenated derivatives were detected.

  18. Diffusion method of seperating gaseous mixtures

    DOEpatents

    Pontius, Rex B.

    1976-01-01

    A method of effecting a relatively large change in the relative concentrations of the components of a gaseous mixture by diffusion which comprises separating the mixture into heavier and lighter portions according to major fraction mass recycle procedure, further separating the heavier portions into still heavier subportions according to a major fraction mass recycle procedure, and further separating the lighter portions into still lighter subportions according to a major fraction equilibrium recycle procedure.

  19. Contribution to the benchmark for ternary mixtures: Measurement of the Soret and thermodiffusion coefficients of tetralin+isobutylbenzene+n-dodecane at a composition of (0.8/0.1/0.1) mass fractions by two-color optical beam deflection.

    PubMed

    Gebhardt, M; Köhler, W

    2015-04-01

    Within the framework of an international benchmark test we have performed measurements of the Soret and thermodiffusion coefficients of the organic ternary mixture (0.8/0.1/0.1 mass fraction) of 1,2,3,4-tetrahydronaphthaline (THN), isobutylbenzene (IBB) and n -dodecane (n C12) at 298.15K by means of a two-color optical beam deflection technique (OBD). The data evaluation procedure is based on a least squares fitting routine for an approximate analytical solution for the Soret cell problem. The condition number of the contrast factor matrix and standard error propagation are used for an error estimation for the measured Soret and thermodiffusion coefficients. The Soret coefficients obtained are S (') T(THN) = (1.20±0.09)×10(-3) K^-1, S (') T(IBB) = (- 0.34±0.14)×10(-3) K^-1, and S (') T(nC12) = (- 0.86±0.06)×10(-3) K^-1 and the corresponding thermodiffusion coefficients are D (') T(THN) = (0.72±0.26)×10(-12) m^2(s K)^-1, D (') T(IBB) = (- 0.22±0.42)×10(-12) m^2(s K)^-1, and D (') T(nC12) = (- 0.50±0.16)×10(-12) m^2(s K)^-1. These results will be used as ground-based reference data for the DCMIX project, where thermodiffusion experiments of ternary mixtures are measured in a microgravity environment aboard the International Space Station (ISS). PMID:25904305

  20. Compressive Strength and Water Absorption of Pervious Concrete that Using the Fragments of Ceramics and Roof Tiles

    NASA Astrophysics Data System (ADS)

    Prahara, E.; Meilani

    2014-03-01

    Pervious concrete was introduced in America in 2003, popularized by Dan Brown and used as a rigid pavement in the open parking lot. Rigid pavement using pervious concrete can absorb water in the surface to go straight through the concrete to the ground below.This water flow is one of the benefit of using the pervious concrete. Using of wastes such as broken roof and ceramics tiles are not commonly used in Indonesia. Utilization these kind of wastes is predicted lower the compressive strength of pervious concrete as they are used as a substitute for coarse aggregate.In this research, pervious concrete is made using a mixture of the fragment of ceramics and roof tiles.This research using broken ceramics and roof tiles with a grain size that loose from 38 mm sieve, retained on 19 mm sieve and the coarse aggregate from crushed stone that loose 12.5 mm sieve, retained on 9.5 mm sieve. The water cement ratio is 0.3 and to assist the mixing process, the addition of addictive in pervious concrete is used.The size of coarse aggregate used in the mixture affects the strength of pervious concrete. The larger the size of aggregate, the obtained compressive strength becomes smaller. It also affects the density of pervious concrete. The using of mixture of ceramics and roof tiles only reduce 2 MPa of pervious concrete compressive strength so this mixture can be used as a substitute for coarse aggregate with a maximum portion of 30 %. The high porosity of the specimens causes the reduction of pervious concrete density that affect the compressive strength. This high level of porosity can be seen from the high level of water absorption that exceed the required limit of water infiltration.

  1. Integrated approach for investigating the durability of self-consolidating concrete to sulfate attack

    NASA Astrophysics Data System (ADS)

    Bassuoni, Mohamed Tamer F.

    The growing use of self-consolidating concrete (SCC) in various infrastructure applications exposed to sulfate-rich environments necessitates conducting comprehensive research to evaluate its durability to external sulfate attack. Since the reliability and adequacy of standard sulfate immersion tests have been questioned, the current thesis introduced an integrated testing approach for assessing the durability of a wide scope of SCC mixtures to external sulfate attack. This testing approach involved progressive levels of complexity from single to multiple damage processes. A new series of sulfate attack tests involving multiple field-like parameters and combined damage mechanisms (various cations, controlled pH, wetting-drying, partial immersion, freezing-thawing, and cyclic cold-hot conditions with or without sustained flexural loading) were designed to evaluate the performance (suitability) of the SCC mixtures under various sulfate attack exposure scenarios. The main mixture design variables of SCC included the type of binder (single, binary, ternary and quaternary), air-entrainment, sand-to-aggregate mass ratio and hybrid fibre reinforcement. The comprehensive database and knowledge obtained from this research were used to develop smart models (fuzzy and neuro-fuzzy inference systems) based on artificial-intelligence to evaluate and predict the performance of the SCC mixtures under various sulfate attack exposure regimes implemented in this study. In full immersion tests involving high concentration sodium and magnesium sulfate solutions with controlled pH, the low penetrability of SCC was responsible for the high durability of specimens. Ternary and quaternary cementitious systems with or without limestone materials provided a passivating layer, with or without acid neutralization capacity, which protected SCC from severe damage in the aggressive sulfuric acid and ammonium sulfate solutions. In contrast to conclusions drawn from the sodium sulfate immersion

  2. Recycled lightweight concrete made from footwear industry waste and CDW.

    PubMed

    Lima, Paulo Roberto Lopes; Leite, Mônica Batista; Santiago, Ediela Quinteiro Ribeiro

    2010-06-01

    In this paper two types of recycled aggregate, originated from construction and demolition waste (CDW) and ethylene vinyl acetate (EVA) waste, were used in the production of concrete. The EVA waste results from cutting off the EVA expanded sheets used to produce insoles and innersoles of shoes in the footwear industry. The goal of this study was to evaluate the influence of the use of these recycled aggregates as replacements of the natural coarse aggregate, upon density, compressive strength, tensile splitting strength and flexural behavior of recycled concrete. The experimental program was developed with three w/c ratios: 0.49, 0.63 and 0.82. Fifteen mixtures were produced with different aggregate substitution rates (0%, 50% EVA, 50% CDW, 25% CDW-25% EVA and 50% CDW-50% EVA), by volume. The results showed that it is possible to use the EVA waste and CDW to produce lightweight concrete having semi-structural properties. PMID:20189792

  3. Testing of Action of Direct Flame on Concrete

    PubMed Central

    Valek, Jaroslav; Novosad, Petr

    2015-01-01

    The paper states results of experimental exposition of concrete test specimens to direct flame. Concrete test specimens made from various mixtures differing in the type of aggregate, binder, dispersed reinforcement, and technological procedure were subjected to thermal load. Physicomechanical and other properties of all test specimens were tested before exposition to open flame: density, compressive strength, flexural strength, moisture content, and surface appearance. The specimens were visually observed during exposition to open flame and changes were recorded. Exposed surface was photographically documented before thermal load and at 10-minute intervals. Development of temperature of the specimens was documented with a thermocamera. After exposition to thermal load and cooling down, concrete specimens were visually observed, network of cracks was photographically documented, and maximal depth of spalled area was measured. PMID:25830162

  4. Treatment of fly ash for use in concrete

    DOEpatents

    Boxley, Chett; Akash, Akash; Zhao, Qiang

    2013-01-08

    A process for treating fly ash to render it highly usable as a concrete additive. A quantity of fly ash is obtained that contains carbon and which is considered unusable fly ash for concrete based upon foam index testing. The fly ash is mixed with an activator solution sufficient to initiate a geopolymerization reaction and for a geopolymerized fly ash. The geopolymerized fly ash is granulated. The geopolymerized fly ash is considered usable fly ash for concrete according to foam index testing. The geopolymerized fly ash may have a foam index less than 35% of the foam index of the untreated fly ash, and in some cases less than 10% of the foam index of the untreated fly ash. The activator solution may contain an alkali metal hydroxide, carbonate, silicate, aluminate, or mixtures thereof.

  5. Treatment of fly ash for use in concrete

    DOEpatents

    Boxley, Chett

    2012-05-15

    A process for treating fly ash to render it highly usable as a concrete additive. A quantity of fly ash is obtained that contains carbon and which is considered unusable fly ash for concrete based upon foam index testing. The fly ash is mixed with a quantity of spray dryer ash (SDA) and water to initiate a geopolymerization reaction and form a geopolymerized fly ash. The geopolymerized fly ash is granulated. The geopolymerized fly ash is considered usable fly ash for concrete according to foam index testing. The geopolymerized fly ash may have a foam index less than 40%, and in some cases less than 20%, of the foam index of the untreated fly ash. An optional alkaline activator may be mixed with the fly ash and SDA to facilitate the geopolymerization reaction. The alkaline activator may contain an alkali metal hydroxide, carbonate, silicate, aluminate, or mixtures thereof.

  6. Treatment of fly ash for use in concrete

    DOEpatents

    Boxley, Chett; Akash, Akash; Zhao, Qiang

    2012-05-08

    A process for treating fly ash to render it highly usable as a concrete additive. A quantity of fly ash is obtained that contains carbon and which is considered unusable fly ash for concrete based upon foam index testing. The fly ash is mixed with an activator solution sufficient to initiate a geopolymerization reaction and for a geopolymerized fly ash. The geopolymerized fly ash is granulated. The geopolymerized fly ash is considered usable fly ash for concrete according to foam index testing. The geopolymerized fly ash may have a foam index less than 35% of the foam index of the untreated fly ash, and in some cases less than 10% of the foam index of the untreated fly ash. The activator solution may contain an alkali metal hydroxide, carbonate, silicate, aluminate, or mixtures thereof.

  7. Acoustic emission monitoring of recycled aggregate concrete under bending

    NASA Astrophysics Data System (ADS)

    Tsoumani, A. A.; Barkoula, N.-M.; Matikas, T. E.

    2015-03-01

    The amount of construction and demolition waste has increased considerably over the last few years, making desirable the reuse of this waste in the concrete industry. In the present study concrete specimens are subjected at the age of 28 days to four-point bending with concurrent monitoring of their acoustic emission (AE) activity. Several concrete mixtures prepared using recycled aggregates at various percentages of the total coarse aggregate and also a reference mix using natural aggregates, were included to investigate their influence of the recycled aggregates on the load bearing capacity, as well as on the fracture mechanisms. The results reveal that for low levels of substitution the influence of using recycled aggregates on the flexural strength is negligible while higher levels of substitution lead into its deterioration. The total AE activity, as well as the AE signals emitted during failure, was related to flexural strength. The results obtained during test processing were found to be in agreement with visual observation.

  8. Recycled lightweight concrete made from footwear industry waste and CDW.

    PubMed

    Lima, Paulo Roberto Lopes; Leite, Mônica Batista; Santiago, Ediela Quinteiro Ribeiro

    2010-06-01

    In this paper two types of recycled aggregate, originated from construction and demolition waste (CDW) and ethylene vinyl acetate (EVA) waste, were used in the production of concrete. The EVA waste results from cutting off the EVA expanded sheets used to produce insoles and innersoles of shoes in the footwear industry. The goal of this study was to evaluate the influence of the use of these recycled aggregates as replacements of the natural coarse aggregate, upon density, compressive strength, tensile splitting strength and flexural behavior of recycled concrete. The experimental program was developed with three w/c ratios: 0.49, 0.63 and 0.82. Fifteen mixtures were produced with different aggregate substitution rates (0%, 50% EVA, 50% CDW, 25% CDW-25% EVA and 50% CDW-50% EVA), by volume. The results showed that it is possible to use the EVA waste and CDW to produce lightweight concrete having semi-structural properties.

  9. Concrete lunar base investigation

    NASA Technical Reports Server (NTRS)

    Lin, T. D.; Senseny, Jonathan A.; Arp, Larry D.; Lindbergh, Charles

    1992-01-01

    This paper presents results of structural analyses and a preliminary design of a precast, prestressed concrete lunar base subjected to 1-atm internal pressure. The proposed infrastructure measures 120 ft in diameter and 72 ft in height, providing 33,000 sq ft of work area for scientific and industrial operations. Three loading conditions were considered in the design (1) during construction, (2) under pressurization, and (3) during an air-leak scenario. A floating foundation, capable of rigid body rotation and translation as the lunar soil beneath it yields, was developed to support the infrastructure and to ensure the airtightness of the system. Results reveal that it is feasible to use precast, prestressed concrete for construction of large lunar bases on the Moon.

  10. Concrete lunar base investigation

    NASA Technical Reports Server (NTRS)

    Lin, T. D.; Senseney, Jonathan A.; Arp, Larry Dean; Lindbergh, Charles

    1989-01-01

    This paper presents results of structural analyses and a preliminary design of a precast, prestressed concrete lunar based subjected to one atmosphere internal pressure. The proposed infrastructure measures 120 ft in diameter and 72 ft in height, providing 33,000 sq ft of work area for scientific and industrial operations. Three loading conditions were considered in the design: (1) during construction; (2) under pressurization; and (3) during an air-leak scenario. A floating foundation, capable of rigid body rotation and translation as the lunar soil beneath it yields, was developed to support the infrastructure and to ensure the air-tightness of the system. Results reveal that it is feasible to use precast, prestressed concrete for construction of large lunar bases on the moon.

  11. Concrete containment aging study

    SciTech Connect

    Pachner, J.; Tai, T.M.; Naus, D.

    1994-04-01

    In 1989, IAEA initiated a pilot study on the management of aging of nuclear power plant components. The Phase I and II studies of concrete containment are discussed. With the data base, plant owners will be able to review and enhance their existing programs. IAEA will analyze data provided by participating plants and the report is scheduled to be released by late 1994 (final report release mid-1995).

  12. A combined strategy of mass fragmentation, post-column cobalt complexation and shift in ultraviolet absorption spectra to determine the uridine 5'-diphospho-glucuronosyltransferase metabolism profiling of flavones after oral administration of a flavone mixture in rats.

    PubMed

    Li, Qiang; Wang, Liping; Dai, Peimin; Zeng, Xuejun; Qi, Xiaoxiao; Zhu, Lijun; Yan, Tongmeng; Wang, Ying; Lu, Linlin; Hu, Ming; Wang, Xinchun; Liu, Zhongqiu

    2015-05-22

    The use of dietary flavones is becoming increasingly popular for their prevention of cancers, cardiovascular diseases, and other diseases. Despite many pharmacokinetic studies on flavone mixtures, the position(s) of glucuronidation sites on the flavone skeleton in vivo remain(s) uncertain because of the lack of a convenient method to differentiate the isomers in biological samples. Accordingly, this study aimed to develop a new strategy to identify the position of the mono-O-glucuronide of flavones in vivo and to simultaneously determine the parent agent and its major metabolites responsible for complex pharmacokinetic characteristics. The novel strategy involves accurate mass measurements of flavone glucuronides, their [Co(II) (flavone glucuronide-H) (4,7-diphenyl-1,10-phenanthroline)2](+) complexes generated via the post-column addition of CoBr2 and 4,7-diphenyl-1,10-phenanthroline, and their mass spectrometric fragmentation by UPLC-DAD-Q-TOF and the comparison of retention times with biosynthesized standards of different isomers that were identified by analyzing the shift in UV spectra compared with the spectra of their respective aglycones. We successfully generated a metabolite profiling of flavones in rat plasma after oral administration of a flavone mixture from Dracocephalum moldavica L., which was used here as the model to demonstrate the strategy. Twelve flavone glucuronides, which were glucuronidated derivatives of acacetin, apigenin, luteolin, diosmetin, chrysoeriol and cirsimaritin, were detected and identified. Glucuronidation of the flavone skeleton at the 3'-/7-position was more prevalent, however, luteolin 4'-glucuronide levels exceeded luteolin 7-glucuronide levels. Based on the UDP-glucuronosyltransferase (UGT) metabolism profiling of flavones in rat plasma, six main compounds (tilianin, acacetin 7-glucuronide, apigenin 7-glucuronide, luteolin 3'-glucuronide, acacetin, and apigenin) were selected as pharmacokinetic markers. Pharmacokinetic

  13. Effect of hot-dry environment on fiber-reinforced self-compacting concrete

    NASA Astrophysics Data System (ADS)

    Tioua, Tahar; Kriker, Abdelouahed; Salhi, Aimad; Barluenga, Gonzalo

    2016-07-01

    Drying shrinkage can be a major reason for the deterioration of concrete structures. Variation in ambient temperature and relative humidity cause changes in the properties of hardened concrete which can affect their mechanical and drying shrinkage characteristics. The present study investigated mechanical strength and particularly drying shrinkage properties of self-compacting concretes (SCC) reinforced with date palm fiber exposed to hot and dry environment. In this study a total of nine different fibers reinforced self compacting concrete (FRSCC) mixtures and one mixture without fiber were prepared. The volume fraction and the length of fibers reinforcement were 0.1-0.2-0.3% and 10-20-30 mm. It was observed that drying shrinkage lessened with adding low volumetric fraction and short length of fibers in curing condition (T = 20 °C and RH = 50 ± 5 %), but increased in hot and dry environment.

  14. High temperature concrete composites containing organosiloxane crosslinked copolymers

    DOEpatents

    Zeldin, Arkady; Carciello, Neal; Kukacka, Lawrence; Fontana, Jack

    1980-01-01

    This invention relates to high temperature polymer concrete composites comprising about 10-30% by weight of a liquid monomer mixture consisting essentially of an organosiloxane polymer crosslinked with an olefinically unsaturated monomer selected from the group consisting of styrene, methyl methacrylate, trimethylolpropane trimethacrylate, triallyl cyanurate, n-phenylmalimide, divinyl benzene and mixtures theroef; and about 70-90% by weight of an inert inorganic filler system containing silica sand and preferably a member selected from the group consisting of portland cement, Fe.sub.2 O.sub.3, carbon black and mixtures thereof; and optionally a free radical initiator such as di-tert-butyl peroxide, azobisisobutyronitrile, benzoyl peroxide, lauryl peroxide and other organic peroxides to initiate crosspolymerization of the monomer mixture in the presence of the inorganic filler.

  15. High temperature concrete composites containing organosiloxane crosslinked copolymers

    DOEpatents

    Zeldin, A.; Carciello, N.; Kukacka, L.; Fontana, J.

    High temperature polymer concrete composites comprising about 10 to 30% by weight of a liquid monomer mixture is described. It consists essentially of an organosiloxane polymer crosslinked with an olefinically unsaturated monomer selected from the group consisting of styrene, methyl methacrylate, trimethylolpropane trimethacrylate, triallyl cyanurate, n-phenylmalimide, divinyl benzene and mixtures thereof. About 70 to 90% by weight of an inert inorganic filler system containing silica sand and portland cement, Fe/sub 2/O/sub 3/, carbon black or mixtures thereof. Optionally a free radical initiator such as di-tert-butyl peroxide, azobisisobyutyronitrile, benzoyl peroxide, lauryl peroxide and other organic peroxides are used to initiate crosspolymerization of the monomer mixture in the presence of the inorganic filler.

  16. Evaluating damage potential of cryogenic concrete using acoustic emission sensors and permeability testing

    NASA Astrophysics Data System (ADS)

    Kogbara, Reginald B.; Parsaei, Boback; Iyengar, Srinath R.; Grasley, Zachary C.; Masad, Eyad A.; Zollinger, Dan G.

    2014-04-01

    This study evaluates the damage potential of concrete of different mix designs subjected to cryogenic temperatures, using acoustic emission (AE) and permeability testing. The aim is to investigate design methodologies that might be employed to produce concrete that resists damage when cooled to cryogenic temperatures. Such concrete would be suitable for primary containment of liquefied natural gas (LNG) and could replace currently used 9% Ni steel, thereby leading to huge cost savings. In the experiments described, concrete cubes, 150 mm x 150 mm x 150 mm, were cast using four different mix designs. The four mixes employed siliceous river sand as fine aggregate. Moreover, limestone, sandstone, trap rock and lightweight aggregate were individually used as coarse aggregates in the mixes. The concrete samples were then cooled from room temperature (20°C) to cryogenic temperature (-165°C) in a temperature chamber. AE sensors were placed on the concrete cubes during the cryogenic freezing process. The damage potential was evaluated in terms of the growth of damage as determined from AE, as a function of temperature and concrete mixture design. The damage potential observed was validated with water permeability testing. Initial results demonstrate the effects of the coefficient of thermal expansion (CTE) of the aggregates on damage growth. Concrete damage (cracking) resistance generally decreased with increasing coarse aggregate CTE, and was in the order, limestone ≥ trap rock << lightweight aggregate ≥ sandstone. Work is in progress to fully understand thermal dilation and damage growth in concrete due to differential CTE of its components.

  17. Fracture Behavior and Properties of Functionally Graded Fiber-Reinforced Concrete

    SciTech Connect

    Roesler, Jeffery; Bordelon, Amanda; Gaedicke, Cristian; Park, Kyoungsoo; Paulino, Glaucio

    2008-02-15

    In concrete pavements, a single concrete mixture design is selected to resist mechanical loading without attempting to adversely affect the concrete pavement shrinkage, ride quality, or noise attenuation. An alternative approach is to design distinct layers within the concrete pavement surface which have specific functions thus achieving higher performance at a lower cost. The objective of this research was to address the structural benefits of functionally graded concrete materials (FGCM) for rigid pavements by testing and modeling the fracture behavior of different combinations of layered plain and synthetic fiber-reinforced concrete materials. Fracture parameters and the post-peak softening behavior were obtained for each FGCM beam configuration by the three point bending beam test. The peak loads and initial fracture energy between the plain, fiber-reinforced, and FGCM signified similar crack initiation. The total fracture energy indicated improvements in fracture behavior of FGCM relative to full-depth plain concrete. The fracture behavior of FGCM depended on the position of the fiber-reinforced layer relative to the starter notch. The fracture parameters of both fiber-reinforced and plain concrete were embedded into a finite element-based cohesive zone model. The model successfully captured the experimental behavior of the FGCMs and predicted the fracture behavior of proposed FGCM configurations and structures. This integrated approach (testing and modeling) demonstrates the viability of FGCM for designing layered concrete pavements system.

  18. Performance of volcanic ash and pumice based blended cement concrete in mixed sulfate environment

    SciTech Connect

    Hossain, K.M.A. . E-mail: ahossain@ryerson.ca; Lachemi, M.

    2006-06-15

    The deterioration of concrete structures due to the presence of mixed sulfate in soils, groundwater and marine environments is a well-known phenomenon. The use of blended cements incorporating supplementary cementing materials and cements with low C{sub 3}A content is becoming common in such aggressive environments. This paper presents the results of an investigation on the performance of 12 volcanic ash (VA) and finely ground volcanic pumice (VP) based ASTM Type I and Type V (low C{sub 3}A) blended cement concrete mixtures with varying immersion period of up to 48 months in environments characterized by the presence of mixed magnesium-sodium sulfates. The concrete mixtures comprise a combination of two Portland cements (Type I and Type V) and four VA/VP based blended cements with two water-to-binder ratio of 0.35 and 0.45. Background experiments (in addition to strength and fresh properties) including X-ray diffraction (XRD), Differential scanning calorimetry (DSC), mercury intrusion porosimetry (MIP) and rapid chloride permeability (RCP) were conducted on all concrete mixtures to determine phase composition, pozzolanic activity, porosity and chloride ion resistance. Deterioration of concrete due to mixed sulfate attack and corrosion of reinforcing steel were evaluated by assessing concrete weight loss and measuring corrosion potentials and polarization resistance at periodic intervals throughout the immersion period of 48 months. Plain (Type I/V) cement concretes, irrespective of their C{sub 3}A content performed better in terms of deterioration and corrosion resistance compared to Type I/V VA/VP based blended cement concrete mixtures in mixed sulfate environment.

  19. A multiscale model for predicting the viscoelastic properties of asphalt concrete

    NASA Astrophysics Data System (ADS)

    Garcia Cucalon, Lorena; Rahmani, Eisa; Little, Dallas N.; Allen, David H.

    2016-08-01

    It is well known that the accurate prediction of long term performance of asphalt concrete pavement requires modeling to account for viscoelasticity within the mastic. However, accounting for viscoelasticity can be costly when the material properties are measured at the scale of asphalt concrete. This is due to the fact that the material testing protocols must be performed recursively for each mixture considered for use in the final design.

  20. High performance of treated and washed MSWI bottom ash granulates as natural aggregate replacement within earth-moist concrete.

    PubMed

    Keulen, A; van Zomeren, A; Harpe, P; Aarnink, W; Simons, H A E; Brouwers, H J H

    2016-03-01

    Municipal solid waste incineration bottom ash was treated with specially designed dry and wet treatment processes, obtaining high quality bottom ash granulate fractions (BGF) suitable for up to 100% replacement of natural gravel in concrete. The wet treatment (using only water for separating and washing) significantly lowers the leaching of e.g. chloride and sulfate, heavy metals (antimony, molybdenum and copper) and dissolved organic carbon (DOC). Two potential bottom ash granulate fractions, both in compliance with the standard EN 12620 (aggregates for concrete), were added into earth-moist concrete mixtures. The fresh and hardened concrete physical performances (e.g. workability, strength and freeze-thaw) of high strength concrete mixtures were maintained or improved compared with the reference mixtures, even after replacing up to 100% of the initial natural gravel. Final element leaching of monolithic and crushed granular state BGF containing concretes, showed no differences with the gravel references. Leaching of all mixtures did not exceed the limit values set by the Dutch Soil Quality Degree. In addition, multiple-life-phase emission (pH static test) for the critical elements of input bottom ash, bottom ash granulate (BGF) and crushed BGF containing concrete were assessed. Simulation pH lowering or potential carbonation processes indicated that metal (antimony, barium, chrome and copper) and sulfate element leaching behavior are mainly pH dominated and controlled, although differ in mechanism and related mineral abundance.

  1. High performance of treated and washed MSWI bottom ash granulates as natural aggregate replacement within earth-moist concrete.

    PubMed

    Keulen, A; van Zomeren, A; Harpe, P; Aarnink, W; Simons, H A E; Brouwers, H J H

    2016-03-01

    Municipal solid waste incineration bottom ash was treated with specially designed dry and wet treatment processes, obtaining high quality bottom ash granulate fractions (BGF) suitable for up to 100% replacement of natural gravel in concrete. The wet treatment (using only water for separating and washing) significantly lowers the leaching of e.g. chloride and sulfate, heavy metals (antimony, molybdenum and copper) and dissolved organic carbon (DOC). Two potential bottom ash granulate fractions, both in compliance with the standard EN 12620 (aggregates for concrete), were added into earth-moist concrete mixtures. The fresh and hardened concrete physical performances (e.g. workability, strength and freeze-thaw) of high strength concrete mixtures were maintained or improved compared with the reference mixtures, even after replacing up to 100% of the initial natural gravel. Final element leaching of monolithic and crushed granular state BGF containing concretes, showed no differences with the gravel references. Leaching of all mixtures did not exceed the limit values set by the Dutch Soil Quality Degree. In addition, multiple-life-phase emission (pH static test) for the critical elements of input bottom ash, bottom ash granulate (BGF) and crushed BGF containing concrete were assessed. Simulation pH lowering or potential carbonation processes indicated that metal (antimony, barium, chrome and copper) and sulfate element leaching behavior are mainly pH dominated and controlled, although differ in mechanism and related mineral abundance. PMID:26856445

  2. Eco-friendly porous concrete using bottom ash aggregate for marine ranch application.

    PubMed

    Lee, Byung Jae; Prabhu, G Ganesh; Lee, Bong Chun; Kim, Yun Yong

    2016-03-01

    This article presents the test results of an investigation carried out on the reuse of coal bottom ash aggregate as a substitute material for coarse aggregate in porous concrete production for marine ranch applications. The experimental parameters were the rate of bottom ash aggregate substitution (30%, 50% and 100%) and the target void ratio (15%, 20% and 25%). The cement-coated granular fertiliser was substituted into a bottom ash aggregate concrete mixture to improve marine ranch applications. The results of leaching tests revealed that the bottom ash aggregate has only a negligible amount of the ten deleterious substances specified in the Ministry of Environment - Enforcement Regulation of the Waste Management Act of Republic Korea. The large amount of bubbles/air gaps in the bottom ash aggregate increased the voids of the concrete mixtures in all target void ratios, and decreased the compressive strength of the porous concrete mixture; however, the mixture substituted with 30% and 10% of bottom ash aggregate and granular fertiliser, respectively, showed an equal strength to the control mixture. The sea water resistibility of the bottom ash aggregate substituted mixture was relatively equal to that of the control mixture, and also showed a great deal of improvement in the degree of marine organism adhesion compared with the control mixture. No fatality of fish was observed in the fish toxicity test, which suggested that bottom ash aggregate was a harmless material and that the combination of bottom ash aggregate and granular fertiliser with substitution rates of 30% and 10%, respectively, can be effectively used in porous concrete production for marine ranch application.

  3. Chlorine signal attenuation in concrete.

    PubMed

    Naqvi, A A; Maslehuddin, M; ur-Rehman, Khateeb; Al-Amoudi, O S B

    2015-11-01

    The intensity of prompt gamma-ray was measured at various depths from chlorine-contaminated silica fume (SF) concrete slab concrete specimens using portable neutron generator-based prompt gamma-ray setup. The intensity of 6.11MeV chloride gamma-rays was measured from the chloride contaminated slab at distance of 15.25, 20.25, 25.25, 30.25 and 35.25cm from neutron target in a SF cement concrete slab specimens. Due to attenuation of thermal neutron flux and emitted gamma-ray intensity in SF cement concrete at various depths, the measured intensity of chlorine gamma-rays decreases non-linearly with increasing depth in concrete. A good agreement was noted between the experimental results and the results of Monte Carlo simulation. This study has provided useful experimental data for evaluating the chloride contamination in the SF concrete utilizing gamma-ray attenuation method.

  4. Ion Mobility Mass Spectrometry for Extracting Spectra of N-Glycans Directly from Incubation Mixtures Following Glycan Release: Application to Glycans from Engineered Glycoforms of Intact, Folded HIV gp120

    NASA Astrophysics Data System (ADS)

    Harvey, David J.; Sobott, Frank; Crispin, Max; Wrobel, Antoni; Bonomelli, Camille; Vasiljevic, Snezana; Scanlan, Christopher N.; Scarff, Charlotte A.; Thalassinos, Konstantinos; Scrivens, James H.

    2011-03-01

    The analysis of glycosylation from native biological sources is often frustrated by the low abundances of available material. Here, ion mobility combined with electrospray ionization mass spectrometry have been used to extract the spectra of N-glycans released with PNGase F from a serial titration of recombinantly expressed envelope glycoprotein, gp120, from the human immunodeficiency virus (HIV). Analysis was also performed on gp120 expressed in the α-mannosidase inhibitor, and in a matched mammalian cell line deficient in GlcNAc transferase I. Without ion mobility separation, ESI spectra frequently contained no observable ions from the glycans whereas ions from other compounds such as detergents and residual buffer salts were abundant. After ion mobility separation on a Waters T-wave ion mobility mass spectrometer, the N-glycans fell into a unique region of the ion mobility/ m/z plot allowing their profiles to be extracted with good signal:noise ratios. This method allowed N-glycan profiles to be extracted from crude incubation mixtures with no clean-up even in the presence of surfactants such as NP40. Furthermore, this technique allowed clear profiles to be obtained from sub-microgram amounts of glycoprotein. Glycan profiles were similar to those generated by MALDI-TOF MS although they were more susceptible to double charging and fragmentation. Structural analysis could be accomplished by MS/MS experiments in either positive or negative ion mode but negative ion mode gave the most informative spectra and provided a reliable approach to the analysis of glycans from small amounts of glycoprotein.

  5. Optimization of reinforced concrete slabs

    NASA Technical Reports Server (NTRS)

    Ferritto, J. M.

    1979-01-01

    Reinforced concrete cells composed of concrete slabs and used to limit the effects of accidental explosions during hazardous explosives operations are analyzed. An automated design procedure which considers the dynamic nonlinear behavior of the reinforced concrete of arbitrary geometrical and structural configuration subjected to dynamic pressure loading is discussed. The optimum design of the slab is examined using an interior penalty function. The optimization procedure is presented and the results are discussed and compared with finite element analysis.

  6. Concrete with carpet recyclates: suitability assessment by surface energy evaluation.

    PubMed

    Schmidt, H; Cieślak, M

    2008-01-01

    Worn out textile floor coverings are burdensome wastes that are degraded in landfill sites after a very long period of time. One of the ways to manage this kind of waste may be the use of carpet recyclate (CR) as an additive for concrete reinforcement. Therefore, an attempt was made to predict the effects of recyclate additives on the durability a concrete-carpet mixture by employing the method of assessing surface properties of components in the concrete-carpet recyclates composite. Testing was performed on carpet wastes, containing polyamide (PA) and polypropylene (PP) piles and butadiene-styrene resin with chalk filler (BSC) as back coating, to assess the suitability of CR additive for concrete reinforcement by surface energy evaluation. Based on the measurements of contact angles, the free surface energy of recyclate components was determined. The reversible work of adhesion at the interface between these components in dry and wet states was also calculated. The results show that CR with both PA and PP fibers form a strong and water-resistant bond with concrete.

  7. Prolong the life of concrete

    SciTech Connect

    Ilaria, J.E.

    1995-07-01

    The most widely used construction materials are concrete and related cement-based products, such as common building block. The excellent reputation of concrete as a durable material of construction has been questioned i modern times. The expanded use of Portland cement concrete, the increase in corrosive environments, and lack of understanding of the composition of concrete all indicate a need for methods to increase life expectancy. Chemical and mechanical factors can shorten service life. Understanding these properties will lead to the proper application of protective coatings.

  8. Microwave NDE for Reinforced Concrete

    NASA Astrophysics Data System (ADS)

    Arunachalam, Kavitha; Melapudi, Vikram R.; Rothwell, Edward J.; Udpa, Lalita; Udpa, Satish S.

    2006-03-01

    Nondestructive assessment of the integrity of civil structures is of paramount importance for ensuring safety. In concrete imaging, radiography, ground penetrating radar and infrared thermography are some of the widely used techniques for health monitoring. Other emerging technologies that are gaining impetus for detecting and locating flaws in steel reinforcement bar include radioactive computed tomography, microwave holography, microwave and acoustic tomography. Of all the emerging techniques, microwave NDT is a promising imaging modality largely due to their ability to penetrate thick concrete structures, contrast between steel rebar and concrete and their non-radioactive nature. This paper investigates the feasibility of a far field microwave NDE technique for reinforced concrete structures.

  9. Abrasion-erosion resistance of concrete made with two aggregates, Stonewall Jackson Dam, West Virginia

    NASA Astrophysics Data System (ADS)

    Holland, T. C.

    1983-09-01

    The resistance to abrasion-erosion of two concretes made with different coarse aggregates was evaluated. The aggregates used were selected as being representative of those that may be selected for use during construction of Stonewall Jackson Dam. The two coarse aggregates were limestones from different sources. All other concrete ingredients were identical for the two mixtures. Both concretes showed very high abrasion-erosion losses when tested using the Corps of Engineers standard test method. A recommendation was made that coarse aggregates with better wear-resistant properties be selected for use in areas of the structure that may be subjected to abrasion-erosion.

  10. Recycling of rubble from building demolition for low-shrinkage concretes.

    PubMed

    Corinaldesi, Valeria; Moriconi, Giacomo

    2010-04-01

    In this project concrete mixtures were prepared that were characterized by low ductility due to desiccation by using debris from building demolition, which after a suitable treatment was used as aggregate for partial replacement of natural aggregates. The recycled aggregate used came from a recycling plant, in which rubble from building demolition was selected, crushed, cleaned, sieved, and graded. Such aggregates are known to be more porous as indicated by the Saturated Surface Dry (SSD) moisture content. The recycled concrete used as aggregates were added to the concrete mixture in order to study their influence on the fresh and hardened concrete properties. They were added either after water pre-soaking or in dry condition, in order to evaluate the influence of moisture in aggregates on the performance of concrete containing recycled aggregate. In particular, the effect of internal curing, due to the use of such aggregates, was studied. Concrete behavior due to desiccation under dehydration was studied by means of both drying shrinkage test and German angle test, through which shrinkage under the restrained condition of early age concrete can be evaluated. PMID:20022737

  11. Recycling of rubble from building demolition for low-shrinkage concretes.

    PubMed

    Corinaldesi, Valeria; Moriconi, Giacomo

    2010-04-01

    In this project concrete mixtures were prepared that were characterized by low ductility due to desiccation by using debris from building demolition, which after a suitable treatment was used as aggregate for partial replacement of natural aggregates. The recycled aggregate used came from a recycling plant, in which rubble from building demolition was selected, crushed, cleaned, sieved, and graded. Such aggregates are known to be more porous as indicated by the Saturated Surface Dry (SSD) moisture content. The recycled concrete used as aggregates were added to the concrete mixture in order to study their influence on the fresh and hardened concrete properties. They were added either after water pre-soaking or in dry condition, in order to evaluate the influence of moisture in aggregates on the performance of concrete containing recycled aggregate. In particular, the effect of internal curing, due to the use of such aggregates, was studied. Concrete behavior due to desiccation under dehydration was studied by means of both drying shrinkage test and German angle test, through which shrinkage under the restrained condition of early age concrete can be evaluated.

  12. Relating damage evolution of concrete cooled to cryogenic temperatures to permeability

    NASA Astrophysics Data System (ADS)

    Kogbara, Reginald B.; Iyengar, Srinath R.; Grasley, Zachary C.; Rahman, Syeda; Masad, Eyad A.; Zollinger, Dan G.

    2014-11-01

    Typically, 9% Ni steel is used for primary containment of liquefied natural gas (LNG). Utilization of concrete in place of 9% Ni steel for primary containment would lead to significant cost savings. Hence, this study investigates changes in the microstructure of concrete due to cryogenic freezing that would affect its relevant engineering properties for containment. The study also evaluates the effect of aggregate type on the damage potential of concrete subjected to cryogenic freezing. The aim is to investigate design methodologies to produce damage-resistant cryogenic concrete. The study employed four concrete mixture designs involving river sand as fine aggregate, and coarse aggregates with different coefficient of thermal expansion (CTE) values. Specifically, the coarse aggregates were limestone, sandstone, trap rock and lightweight aggregate. Concrete cubes were cured under water for at least 28 days and thereafter frozen from ambient (20 °C) to cryogenic temperature (-165 °C). Acoustic emission (AE) sensors were placed on the concrete cubes during freezing. X-ray computed tomography (XRCT) was employed to study the microstructure of concrete cores, before and after cryogenic freezing. The impact of the microstructural evolution thus obtained from AE and XRCT on relevant engineering properties was determined via water and chloride permeability tests. Microcrack propagation determined from AE correlated with changes in permeability. There were no observable cracks in majority of the concrete mixtures after freezing. This implies that microcracks detected via AE and increased permeability was very well distributed and smaller than the XRCT's resolution. Damage (microcracking) resistance of the concrete with different aggregates was in the order limestone ⩾ trap rock ≫ lightweight aggregate ⩾ sandstone.

  13. Temperature and pore pressure distribution in a concrete slab during the microwave decontamination process

    SciTech Connect

    Li, W.; Ebadian, M.A.; White, T.L.; Grubb, R.G.; Foster, D. Jr.

    1994-10-01

    As an application of microwave engineering, the new technology of concrete decontamination and decommissioning using microwave energy has been recently developed. The temperature and pore pressure within the concrete are studied theoretically in this paper. The heat and mass transfer within the porous concrete, coupled with temperature dependent dielectric property are investigated. The effects of microwave frequency (f), microwave power intensity (Q{sub 0,ave}), concrete porosity ({phi}) on the temperature and pore pressure distributions and their variations are fully discussed. The effects of the variation of complex dielectric permittivity ({epsilon}) and presentation of different steel reinforcements are also illustrated.

  14. Performance of concrete barriers in radioactive waste disposal in the unsaturated zone

    SciTech Connect

    Walton, J.C. ); Otis, M.D. )

    1989-09-14

    Concrete barriers are an important component of many designs for disposal of radioactive waste in the unsaturated zone. In order to evaluate the effectiveness of the concrete barriers performance assessment models representing the material degradation rates and transport properties must be developed. Models for evaluation of fluid flow and mass transport through partially failed concrete barriers located in the unsaturated zone are presented. Implications of the use of impermeable barriers design are discussed. Concrete of highest quality may not always be desirable for use in all components of waste disposal vaults. 7 refs., 5 figs.

  15. Transport processes in partially saturate concrete: Testing and liquid properties

    NASA Astrophysics Data System (ADS)

    Villani, Chiara

    The measurement of transport properties of concrete is considered by many to have the potential to serve as a performance criterion that can be related to concrete durability. However, the sensitivity of transport tests to several parameters combined with the low permeability of concrete complicates the testing. Gas permeability and diffusivity test methods are attractive due to the ease of testing, their non-destructive nature and their potential to correlate to in-field carbonation of reinforced concrete structures. This work was aimed at investigating the potential of existing gas transport tests as a way to reliably quantify transport properties in concrete. In this study gas permeability and diffusivity test methods were analyzed comparing their performance in terms of repeatability and variability. The influence of several parameters was investigated such as moisture content, mixture proportions and gas flow. A closer look to the influence of pressure revealed an anomalous trend of permeability with respect to pressure. An alternative calculation is proposed in an effort to move towards the determination of intrinsic material properties that can serve as an input for service life prediction models. The impact of deicing salts exposure was also analyzed with respect to their alteration of the degree of saturation as this may affect gas transport in cementitious materials. Limited information were previously available on liquid properties over a wide range of concentrations. To overcome this limitation, this study quantified surface tension, viscosity in presence of deicing salts in a broad concentration range and at different temperatures. Existing models were applied to predict the change of fluid properties during drying. Vapor desorption isotherms were obtained to investigate the influence of deicing salts presence on the non-linear moisture diffusion coefficient. Semi-empirical models were used to quantify the initiation and the rate of drying using liquid

  16. Concrete Mixing Methods and Concrete Mixers: State of the Art.

    PubMed

    Ferraris, C F

    2001-01-01

    As for all materials, the performance of concrete is determined by its microstructure. Its microstructure is determined by its composition, its curing conditions, and also by the mixing method and mixer conditions used to process the concrete. This paper gives an overview of the various types of mixing methods and concrete mixers commercially available used by the concrete industry. There are two main types of mixers used: batch mixers and continuous mixers. Batch mixers are the most common. To determine the mixing method best suited for a specific application, factors to be considered include: location of the construction site (distance from the batching plant), the amount of concrete needed, the construction schedule (volume of concrete needed per hour), and the cost. Ultimately, the quality of the concrete produced determines its performance after placement. An important measure of the quality is the homogeneity of the material after mixing. This paper will review mixing methods in regards to the quality of the concrete produced. Some procedures used to determine the effectiveness of the mixing will be examined.

  17. Concrete Mixing Methods and Concrete Mixers: State of the Art

    PubMed Central

    Ferraris, Chiara F.

    2001-01-01

    As for all materials, the performance of concrete is determined by its microstructure. Its microstructure is determined by its composition, its curing conditions, and also by the mixing method and mixer conditions used to process the concrete. This paper gives an overview of the various types of mixing methods and concrete mixers commercially available used by the concrete industry. There are two main types of mixers used: batch mixers and continuous mixers. Batch mixers are the most common. To determine the mixing method best suited for a specific application, factors to be considered include: location of the construction site (distance from the batching plant), the amount of concrete needed, the construction schedule (volume of concrete needed per hour), and the cost. Ultimately, the quality of the concrete produced determines its performance after placement. An important measure of the quality is the homogeneity of the material after mixing. This paper will review mixing methods in regards to the quality of the concrete produced. Some procedures used to determine the effectiveness of the mixing will be examined. PMID:27500029

  18. Gaseous mercury release during steam curing of aerated concretes that contain fly ash and activated carbon sorbent

    SciTech Connect

    Danold W. Golightly; Chin-Min Cheng; Ping Sun; Linda K. Weavers; Harold W. Walker; Panuwat Taerakul; William E. Wolfe

    2008-09-15

    Gaseous mercury released from aerated concrete during both presteam curing at 25{sup o}C and steam curing at 80{sup o}C was measured in controlled laboratory experiments. Mercury release originated from two major components in the concrete mixture: (1) class F coal fly ash and (2) a mixture of the fly ash and powdered activated carbon onto which elemental mercury was adsorbed. Mercury emitted during each curing cycle was collected on iodated carbon traps in a purge-and-trap arrangement and subsequently measured by cold-vapor atomic fluorescence spectrometry. Through 3 h of presteam curing, the release of mercury from the freshly prepared mixture was less than 0.03 ng/kg of concrete. Releases of total mercury over the 21 h steam curing process ranged from 0.4 to 5.8 ng of mercury/kg of concrete and depended upon mercury concentrations in the concrete. The steam-cured concrete had a higher mercury release rate (ng kg{sup -1} h{sup -1}) compared to air-cured concrete containing fly ash, but the shorter curing interval resulted in less total release of mercury from the steam-cured concrete. The mercury flux from exposed concrete surfaces to mercury-free air ranged from 0.77 to 11.1 ng m{sup -2} h{sup -1}, which was similar to mercury fluxes for natural soils to ambient air of 4.2 ng m{sup -2} h{sup -1} reported by others. Less than 0.022% of the total quantity of mercury present from all mercury sources in the concrete was released during the curing process, and therefore, nearly all of the mercury was retained in the concrete. 31 refs., 4 figs., 2 tabs.

  19. Corrosion control of steel-reinforced concrete

    NASA Astrophysics Data System (ADS)

    Chung, D. D. L.

    2000-10-01

    The methods and materials for corrosion control of steel-reinforced concrete are reviewed. The methods are steel surface treatment, the use of admixtures in concrete, surface coating on concrete, and cathodic protection.

  20. Coal fly ash: the most powerful tool for sustainability of the concrete industry

    SciTech Connect

    Mehta, P.K.

    2008-07-01

    In the last 15 years the global cement industry has almost doubled its annual rate of direct emissions of carbon dioxide. These can be cut back by reducing global concrete consumption, reducing the volume of cement paste in mixtures and reducing the proportion of portland clinker in cement. It has recently been proved that use of high volumes of coal fly ash can produce low cost, durable, sustainable cement and concrete mixtures that would reduce the carbon footprint of both the cement and the power generation industries. 2 photos.

  1. Alkali-silica reaction resistant concrete using pumice blended cement

    NASA Astrophysics Data System (ADS)

    Ramasamy, Uma

    Durability of structures is a major challenge for the building industry. One of the many types of concrete deterioration that can affect durability is alkali-silica reaction (ASR). ASR has been found in most types of concrete structures, including dams, bridges, pavements, and other structures that are 20 to 50 years old. The degradation mechanism of ASR produces a gel that significantly expands in the presence of water as supplied from the surrounding environment. This expansion gel product can create high stresses and cracking of the concrete, which can lead to other forms of degradation and expensive structural replacement costs. The four essential factors that produce an expansive ASR gel in concrete are the presence of alkalis, siliceous aggregate, moisture, and free calcium hydroxide (CH). If concrete is starved of any one of these essential components, the expansion can be prevented. Reducing CH through the use of a supplementary cementitious material (SCM) such as natural pozzolan pumice is the focus of this research. By using a pozzolan, the amount of CH is reduced with time based on the effectiveness of the pozzolan. Many pozzolans exist, but one such naturally occurring pozzolanic material is pumice. This research focuses on determining the effect of a finely ground pumice as a SCM in terms of its resistance to ASR expansion, as well as improving resistance to other potential concrete durability mechanisms. In spite of having high alkali contents in the pumice, mixtures containing the SCM pumice more effectively mitigated the ASR expansion reaction than other degradation mechanisms. Depending on the reactivity of the aggregates and fineness of the pumice, 10-15% replacement of cement with the pumice was found to reduce the ASR expansion to the acceptable limits. The amount of CH remaining in the concrete was compared to the ASR expansion in order to improve understanding of the role of CH in the ASR reaction. Thermo-gravimetric analysis (TGA) and X

  2. Biodecontamination of radionuclide contaminated concrete

    SciTech Connect

    Hamilton, M.A.; Rogers, R.D.; Benson, J.

    1996-10-01

    Within the nuclear industry, there are literally hundreds of square miles of radionuclide contaminated concrete surfaces. A novel technology for biologically decontaminating concrete is being developed. The technology exploits a naturally occurring phenomenon referred to as microbially influenced degradation (MID) in which bacteria produce acids that dissolve the cement matrix of the concrete. Accelerated testing in laboratory conditions was conducted. The bacteria Thiobacillus thiooxidans, supplied from a continuous flow bioreactor, was applied to an exposed concrete surface. A control chamber exposing concrete to sterile media was operated under the same conditions. One hundred percent of surrogate cobalt contamination was recovered from the Thiobacillus treated concrete and 1 mm thickness of concrete material was removed in 60 days. Prototype chambers that can be mounted directly to concrete surfaces have been designed to allow control of environmental conditions to promote MID after inoculation of the surface with bacteria. Studies to determine optimum source and quantity of reduced sulfur, bacterial species or consortia best suited for rapid MID, and methods of application and delivery of bacteria and nutrients will be discussed.

  3. Concrete Masonry Designs: Educational Issue.

    ERIC Educational Resources Information Center

    Hertzberg, Randi, Ed.

    2001-01-01

    This special journal issue addresses concrete masonry in educational facilities construction. The issue's feature articles are: (1) "It Takes a Village To Construct a Massachusetts Middle School," describing a middle school constructed almost entirely of concrete masonry and modeled after a typical small New England village; (2) "Lessons Learned,"…

  4. The Concrete and Pavement Challenge

    ERIC Educational Resources Information Center

    Roman, Harry T.

    2012-01-01

    The modern world is characterized by the extensive use of concrete and asphalt pavement. Periodically, these materials are replaced and the old materials disposed of. In this challenge, students will be asked to develop ways to reuse the old materials. It is important for students to understand how concrete and asphalt are made and applied, as…

  5. Molded Concrete Center Mine Wall

    NASA Technical Reports Server (NTRS)

    Lewis, E. V.

    1987-01-01

    Proposed semiautomatic system forms concrete-foam wall along middle of coal-mine passage. Wall helps support roof and divides passage into two conduits needed for ventilation of coal face. Mobile mold and concrete-foam generator form sections of wall in place.

  6. Technology Solutions Case Study: Insulating Concrete Forms

    SciTech Connect

    none,

    2012-10-01

    This Pacific Northwest National Laboratory project investigated insulating concrete forms—rigid foam, hollow walls that are filled with concrete for highly insulated, hurricane-resistant construction.

  7. Durability of an inorganic polymer concrete coating

    NASA Astrophysics Data System (ADS)

    Wasserman, Kenneth

    The objective of the research program reported in this thesis is to evaluate the durability of an inorganic polymer composite coating exposed to freeze/thaw cycling and wet-dry cycling. Freeze/thaw cycling is performed following ASTM D6944-09 Standard Practice for Resistance of Cured Coatings to Thermal Cycling and wet/dry cycling is performed following guidelines set forth in a thesis written by Ronald Garon at Rutgers University. For both sets of experiments, four coating mixture proportions were evaluated. The variables were: silica/alumina ratio, mixing protocol using high shear and normal shear mixing, curing temperatures of 70 and 120 degrees Fahrenheit and use of nano size constituent materials. The mix with highest silica/alumina ratio was designated as Mix 1 and mixes with lower ratios were designated as Mix 2 and Mix 3. Mix 4 had nano silica particles. Four prisms were used for each variable including control that had no coating. The performance of the coating was evaluated using adhesion strength measured using: ASTM D7234 Test Method for Pull-Off Strength of Coatings on Concrete Using Portable Adhesion Testers. Tests were performed after every five consecutive cycles of thermal conditioning and six consecutive cycles of wet-dry exposure. Results from the thermal cycling and wet-dry testing demonstrate that all coating formulations are durable. The minimum adhesion strength was 300 psi even though a relatively weak base concrete surface was chosen for the study. The weak surface was chosen to simulate aged concrete surfaces present in actual field conditions. Due to the inherent nature of the test procedure the variation in test results is high. However, based on the test results, high shear mixer and high temperature curing are not recommended. As expected nano size constituent materials provide better performance.

  8. Solar-Array Substrate From Glass-Reinforced Concrete

    NASA Technical Reports Server (NTRS)

    Eirls, J. L.

    1985-01-01

    Design elminiates glass superstrate and associated metal framing. Panel has two trapezoidal stiffening ribs for structural support. Strategic placement of ribs with embedded support tubes (standard PVC tubing) minimizes bending moments and resulting stresses produced by installation and windloads. Glass-reinforced concrete panel has smooth flat surface suitable for solar substrate and includes structural bracing for rigidity and design adaptable to mass production.

  9. The Puzzle of Septarian Concretions

    NASA Astrophysics Data System (ADS)

    John, C. M.; Dale, A.; Mozley, P.; Smalley, P. C.; Muggeridge, A. H.

    2014-12-01

    Carbonate concretions in clastic rocks and their septarian fracture fills act as 'time capsules', capturing the signatures of chemical and biological processes during diagenesis. However, many aspects of the formation of concretions and septarian fractures remain poorly understood, for although concretions occur in clastic rocks throughout the geological record, they are rarely documented in recent shallow-burial environments. Consequently, the depth and temperature at which concretion-forming processes occur are often poorly constrained. Carbonate clumped isotopes have recently been applied successfully to concretions and fracture fills that begin to unravel the conditions for the formation of concretions and septarian fractures. Here, we present carbonate clumped isotope results of fracture fills from eight different concretions from various locations, including multiple phases of fill in 4 concretions. Our results suggest that they precipitated over a range of temperatures (22°C - 85°C) from d18Oporewater values between -12‰ to 3‰ and within different d13Ccarbonate zones. The majority of fills precipitated at lower (<50°C) temperatures, although the fluids were not always meteoric. For 3 concretions containing fractures with multiple phases, the d18Oporewater becomes progressively heavier with each later phase and increasing temperature. The one exception to this is in the Barton Clay Formation (UK) where the fractures must have been continuously filled during exhumation as the latest cement phase is the coolest with a d18Oporewater more 18O-depleted than the earliest phase. Therefore, concretion growth must usually initiate early on (<~1 km burial), and subsequent fracturing is also usually early. However, the fracture infilling can occur over a range of depths and can record the diagenetic history of a formation. We gratefully acknowledge a BP and EPSRC Case Studentship for funding this project, and the Natural History Museum London for providing

  10. Nuclear Power Plant Concrete Structures

    SciTech Connect

    Basu, Prabir; Labbe, Pierre; Naus, Dan

    2013-01-01

    A nuclear power plant (NPP) involves complex engineering structures that are significant items of the structures, systems and components (SSC) important to the safe and reliable operation of the NPP. Concrete is the commonly used civil engineering construction material in the nuclear industry because of a number of advantageous properties. The NPP concrete structures underwent a great degree of evolution, since the commissioning of first NPP in early 1960. The increasing concern with time related to safety of the public and environment, and degradation of concrete structures due to ageing related phenomena are the driving forces for such evolution. The concrete technology underwent rapid development with the advent of chemical admixtures of plasticizer/super plasticizer category as well as viscosity modifiers and mineral admixtures like fly ash and silica fume. Application of high performance concrete (HPC) developed with chemical and mineral admixtures has been witnessed in the construction of NPP structures. Along with the beneficial effect, the use of admixtures in concrete has posed a number of challenges as well in design and construction. This along with the prospect of continuing operation beyond design life, especially after 60 years, the impact of extreme natural events ( as in the case of Fukushima NPP accident) and human induced events (e.g. commercial aircraft crash like the event of September 11th 2001) has led to further development in the area of NPP concrete structures. The present paper aims at providing an account of evolution of NPP concrete structures in last two decades by summarizing the development in the areas of concrete technology, design methodology and construction techniques, maintenance and ageing management of concrete structures.

  11. Evaluation of the stability of a mixture of volatile organic compounds on sorbents for the determination of emissions from indoor materials and products using thermal desorption/gas chromatography/mass spectrometry.

    PubMed

    Brown, Veronica M; Crump, Derrick R; Plant, Neil T; Pengelly, Ian

    2014-07-11

    The standard method for the determination of volatile organic compounds (VOCs) in indoor and test chamber air (ISO 16000-6:2011) specifies sampling onto the sorbent Tenax TA followed by analysis using thermal desorption/gas chromatography/mass spectrometry (TD/GC/MS). The informative Annex D to the standard suggests the use of multi-sorbent samplers to extend the volatility range of compounds which can be determined. The aim of this study was to investigate the storage performance of Tenax TA and two multi-sorbent tubes loaded with a mixture of nine VOCs of relevance for material emissions testing. The sorbent combinations tested were quartz wool/Tenax TA/Carbograph™ 5TD and quartz wool/Tenax TA/Carbopack™ X. A range of loading levels, loading conditions (humidities and air volume), storage times (1-4 weeks) and storage conditions (refrigerated and ambient) were investigated. Longer term storage trials (up to 1 year) were conducted with Tenax TA tubes to evaluate the stability of tubes used for proficiency testing (PT) of material emissions analyses. The storage performance of the multi-sorbent tubes tested was found to be equal to that for Tenax TA, with recoveries after 4 weeks storage of within about 10% of the amounts loaded. No consistent differences in recoveries were found for the different loading or storage conditions. The longer term storage trials also showed good recovery for these compounds, although two other compounds, hexanal and BHT, were found to be unstable when stored on Tenax TA. The results of this study provide confidence in the stability of nine analytes for up to 4 weeks on two multi-sorbent tubes for material emissions testing and the same compounds loaded on Tenax TA sorbent for a recently introduced PT scheme for material emissions testing.

  12. A PERMEABLE ACTIVE AMENDMENT CONCRETE (PAAC) FOR CONTAMINANT REMEDIATION AND EROSION CONTROL

    SciTech Connect

    Knox, A.; Paller, M.; Dixon, K.

    2012-06-29

    The final project report for SEED SERDP ER - 2134 describes the development of permeable active amendment concrete (PAAC), which was evaluated through four tasks: 1) development of PAAC; 2) assessment of PAAC for contaminant removal; 3) evaluation of promising PAAC formulations for potential environmental impacts; and 4) assessment of the hydraulic, physical, and structural properties of PAAC. Conventional permeable concrete (often referred to as pervious concrete) is concrete with high porosity as a result of an extensive and interconnected void content. It is made from carefully controlled amounts of water and cementitious materials used to create a paste that forms a coating around aggregate particles. The mixture has a substantial void content (e.g., 15% - 25%) that results in a highly permeable structure that drains quickly. In PAAC, the aggregate material is partly replaced by chemically-active amendments that precipitate or adsorb contaminants in water that flows through the concrete interstices. PAAC combines the relatively high structural strength, ample void space, and water permeability of pervious concrete with the contaminant sequestration ability of chemically-active amendments to produce a new material with superior durability and ability to control contaminant mobility. The high surface area provided by the concrete interstices in PAAC provides significant opportunity for contaminants to react with the amendments incorporated into the concrete matrix. PAAC has the potential to immobilize a large variety of organic and inorganic contaminants by incorporating different active sequestering agents including phosphate materials (rock phosphate), organoclays, zeolite, and lime individually or in combinations.

  13. Properties of concrete blocks prepared with low grade recycled aggregates.

    PubMed

    Poon, Chi-Sun; Kou, Shi-cong; Wan, Hui-wen; Etxeberria, Miren

    2009-08-01

    Low grade recycled aggregates obtained from a construction waste sorting facility were tested to assess the feasibility of using these in the production of concrete blocks. The characteristics of the sorted construction waste are significantly different from that of crushed concrete rubbles that are mostly derived from demolition waste streams. This is due to the presence of higher percentages of non-concrete components (e.g. >10% soil, brick, tiles etc.) in the sorted construction waste. In the study reported in this paper, three series of concrete block mixtures were prepared by using the low grade recycled aggregates to replace (i) natural coarse granite (10mm), and (ii) 0, 25, 50, 75 and 100% replacement levels of crushed stone fine (crushed natural granite <5mm) in the concrete blocks. Test results on properties such as density, compressive strength, transverse strength and drying shrinkage as well as strength reduction after exposure to 800 degrees C are presented below. The results show that the soil content in the recycled fine aggregate was an important factor in affecting the properties of the blocks produced and the mechanical strength deceased with increasing low grade recycled fine aggregate content. But the higher soil content in the recycled aggregates reduced the reduction of compressive strength of the blocks after exposure to high temperature due probably to the formation of a new crystalline phase. The results show that the low grade recycled aggregates obtained from the construction waste sorting facility has potential to be used as aggregates for making non-structural pre-cast concrete blocks.

  14. Sorptivity of fly ash concretes

    SciTech Connect

    Gopalan, M.K.

    1996-08-01

    A factorial experiment was designed to measure the sorptivity of cement and fly ash concretes in order to compare the durability of fly ash concrete against the cement concrete. Sorptivity measurements based on the capillary movement of water was made on three grades of cement concrete and six grades of fly ash mixes. The effect of curing was also studied by treating the samples in two curving conditions. A functional relationship of sorptivity against the strength, curing condition and fly ash content has been presented. The results were useful to analyze the factors influencing the durability of cement and fly ash concretes and to explain why some of the previously reported findings were contradictory. Curing conditions have been found to be the most important factor that affected the durability properties of fly ash concrete. When proper curing was provided, a mix with 40% fly ash was found to reduce the sorptivity by 37%. Under inadequate curing the sorptivity was found to increase by 60%. The influence of curing on cement concrete was found to be of much less importance.

  15. Carburetor mixture control apparatus

    SciTech Connect

    Dalke, A.E.

    1983-11-29

    A mixture control device is disclosed for automatically controlling the air to fuel mixture of a conventional carburetor involving a plurality of sloped radial vanes circumferentially located within the annulus formed by the booster venturi and the venturi tube. By inducing significant centrifugal motion in the air passing outside the booster venturi the problems associated with fuel to air mixture changes associated with changes in elevation and changes in seasonal temperatures are alleviated.

  16. Testing of concrete by laser ablation

    DOEpatents

    Flesher, D.J.; Becker, D.L.; Beem, W.L.; Berry, T.C.; Cannon, N.S.

    1997-01-07

    A method is disclosed for testing concrete in a structure in situ, by: directing a succession of pulses of laser radiation at a point on the structure so that each pulse effects removal of a quantity of concrete and transfers energy to the concrete; detecting a characteristic of energy which has been transferred to the concrete; determining, separately from the detecting step, the total quantity of concrete removed by the succession of pulses; and calculating a property of the concrete on the basis of the detected energy characteristic and the determined total quantity of concrete removed. 1 fig.

  17. Testing of concrete by laser ablation

    DOEpatents

    Flesher, Dann J.; Becker, David L.; Beem, William L.; Berry, Tommy C.; Cannon, N. Scott

    1997-01-01

    A method of testing concrete in a structure in situ, by: directing a succession of pulses of laser radiation at a point on the structure so that each pulse effects removal of a quantity of concrete and transfers energy to the concrete; detecting a characteristic of energy which has been transferred to the concrete; determining, separately from the detecting step, the total quantity of concrete removed by the succession of pulses; and calculating a property of the concrete on the basis of the detected energy characteristic and the determined total quantity of concrete removed.

  18. Measurement of Workability of Fresh Concrete Using a Mixing Truck.

    PubMed

    Amziane, Sofiane; Ferraris, Chiara F; Koehler, Eric P

    2005-01-01

    The main objective of this study is to evaluate the workability of fresh portland cement concrete while it is still in the mixing truck by determining fundamental rheological parameters (plastic viscosity and yield stress). Nine concrete mixtures with different values of yield stress and plastic viscosity were tested in a concrete truck. The measurements made with the truck were based on the typical method of determining the flow behavior in a traditional fluid rheometer; that is, the shear rate in the mixing truck was swept from high to low by varying the rotation speed of the drum. The results of these experiments are discussed and compared with data provided by the ICAR rheometer, a portable rheometer designed for measuring concrete rheology. The test results indicate that the mixing truck equipment is sufficiently sensitive to detect differences in yield stress, slump, and plastic viscosity. However, the plastic viscosity determined by the truck measurement did not correlate with plastic viscosity as measured by the ICAR rheometer, while the yield stress determined by the truck measurement did correlate well with the measured slump and the ICAR rheometer results Suggestions are given on how to improve the mixing truck for better use as a rheometer.

  19. Measurement of Workability of Fresh Concrete Using a Mixing Truck

    PubMed Central

    Amziane, Sofiane; Ferraris, Chiara F.; Koehler, Eric P.

    2005-01-01

    The main objective of this study is to evaluate the workability of fresh portland cement concrete while it is still in the mixing truck by determining fundamental rheological parameters (plastic viscosity and yield stress). Nine concrete mixtures with different values of yield stress and plastic viscosity were tested in a concrete truck. The measurements made with the truck were based on the typical method of determining the flow behavior in a traditional fluid rheometer; that is, the shear rate in the mixing truck was swept from high to low by varying the rotation speed of the drum. The results of these experiments are discussed and compared with data provided by the ICAR rheometer, a portable rheometer designed for measuring concrete rheology. The test results indicate that the mixing truck equipment is sufficiently sensitive to detect differences in yield stress, slump, and plastic viscosity. However, the plastic viscosity determined by the truck measurement did not correlate with plastic viscosity as measured by the ICAR rheometer, while the yield stress determined by the truck measurement did correlate well with the measured slump and the ICAR rheometer results Suggestions are given on how to improve the mixing truck for better use as a rheometer. PMID:27308103

  20. Optimizing the use of fly ash in concrete

    SciTech Connect

    Thomas, M.

    2007-07-01

    The optimum amount of fly ash varies not only with the application, but also with composition and proportions of all the materials in the concrete mixture (especially the fly ash), the conditions during placing (especially temperature), construction practices (for example, finishing and curing) and the exposure conditions. This document discusses issues related to using low to very high levels of fly ash in concrete and provides guidance for the use of fly ash without compromising the construction process or the quality of the finished product. The nature of fly ashes including their physical, mineralogical and chemical properties is covered in detail, as well as fly ash variability due to coal composition and plant operating conditions. A discussion on the effects of fly ash characteristics on fresh and hardened concrete properties includes; workability, bleeding, air entrainment, setting time, heat of hydration, compressive strength development, creep, drying shrinkage, abrasion resistance, permeability, resistance to chlorides, alkali-silica reaction (ASR), sulfate resistance, carbonation, and resistance to freezing and thawing and deicer salt scaling. Case studies were selected as examples of some of the more demanding applications of fly ash concrete for ASR mitigation, chloride resistance, and green building.

  1. An Unsteady Dual Porosity Representation Of Concrete Rubble Disposal

    SciTech Connect

    Flach, G

    2006-03-29

    Decontamination and decommissioning at the Savannah River Site have produced on-site disposals of low-level solid radioactive waste in the form of concrete rubble. In the case of a former tritium extraction facility, building demolition produced a significant volume of rubble embedded with tritium. The contaminated debris comprises a heterogeneous mixture of sizes, shapes, and internal tritium distributions. The rubble was disposed in long, shallow, unlined, earthen trenches, that were subsequently backfilled with excavated soil and exposed to normal infiltration. To forecast tritium flux to the water table, an unsteady dual porosity model was developed to describe vadose zone leaching and transport. Tritium was assumed to be released through unsteady, one-dimensional, molecular diffusion within concrete, while advective and diffusive transport occur in the surrounding backfill. Rubble size and shape variations were characterized through a combination of physical measurement and photographic image analysis. For simplicity, the characterization data were reduced to an approximately equivalent distribution of one-dimensional slab thicknesses for representation in the dual porosity formulation. Each size classification was simulated separately, and individual flux results were then blended in proportion to the thickness distribution to produce a composite flux. The fractional flux from concrete rubble was predicted to be roughly 40% of that from tritium-contaminated soil. The lower flux is a result of slower release to soil pore water, and a reduced effective trench conductivity from the presence of impervious concrete.

  2. Damage detection and artificial healing of asphalt concrete after trafficking with a load simulator

    NASA Astrophysics Data System (ADS)

    Bueno, M.; Arraigada, M.; Partl, M. N.

    2016-08-01

    Artificial healing of asphalt concrete by induction heating requires the addition of electrically conductive and/or magnetic materials into the asphalt mixture. Hence, bitumen can be heated up by an alternating electromagnetic field, decreasing therefore its viscosity and allowing it to flow for closing cracks and recover bonding among the mineral aggregates.

  3. Effects of fertilizer and pesticides on concrete

    SciTech Connect

    Broder, M.F.; Nguyen, D.T.; Harner, A.L.

    1994-12-31

    Concrete is the most common material of construction for secondary containment of fertilizers and pesticides because of its relative low cost and structural properties. Concrete, however, is porous to some products it is designed to contain and is subject to corrosion. In this paper, concrete deterioration mechanisms and corrosion resistant concrete formulation are discussed, as well as exposure tests of various concrete mixes to some common liquid fertilizers and herbicides.

  4. Electrically conductive polymer concrete coatings

    DOEpatents

    Fontana, J.J.; Elling, D.; Reams, W.

    1990-03-13

    A sprayable electrically conductive polymer concrete coating for vertical d overhead applications is described. The coating is permeable yet has low electrical resistivity (<10 ohm-cm), good bond strength to concrete substrates, and good weatherability. A preferred formulation contains about 60 wt % calcined coke breeze, 40 wt % vinyl ester with 3.5 wt % modified bentonite clay. Such formulations apply evenly and provide enough rigidity for vertical or overhead structures so there is no drip or sag.

  5. Electrically conductive polymer concrete coatings

    DOEpatents

    Fontana, J.J.; Elling, D.; Reams, W.

    1988-05-26

    A sprayable electrically conductive polymer concrete coating for vertical and overhead applications is described. The coating is permeable yet has low electrical resistivity (<10 ohm-cm), good bond strength to concrete substrates, and good weatherability. A preferred formulation contains about 60 wt% calcined coke breeze, 40 wt% vinyl ester resin with 3.5 wt% modified bentonite clay. Such formulations apply evenly and provide enough rigidity for vertical or overhead structures so there is no drip or sag. 4 tabs.

  6. Electrically conductive polymer concrete coatings

    DOEpatents

    Fontana, Jack J.; Elling, David; Reams, Walter

    1990-01-01

    A sprayable electrically conductive polymer concrete coating for vertical d overhead applications is described. The coating is permeable yet has low electrical resistivity (<10 ohm-cm), good bond strength to concrete substrates, and good weatherability. A preferred formulation contains about 60 wt % calcined coke breeze, 40 wt % vinyl ester with 3.5 wt % modified bentonite clay. Such formulations apply evenly and provide enough rigidity for vertical or overhead structures so there is no drip or sag.

  7. Evaluation of Sulfur 'Concrete' for Use as a Construction Material on the Lunar Surface

    NASA Technical Reports Server (NTRS)

    Grugel, R. N.

    2008-01-01

    Combining molten sulfur with any number of aggregate materials forms, when solid, a mixture having attributes similar, if not better, to conventional water-based concrete. As a result the use of sulfur "concrete" on Earth is well established, particularly in corrosive environments. Consequently, discovery of troilite (FeS) on the lunar surface prompted numerous scenarios about its reduction to elemental sulfur for use, in combination with lunar regolith, as a potential construction material; not requiring water, a precious resource, for its manufacture is an obvious advantage. However, little is known about the viability of sulfur concrete in an environment typified by extreme temperatures and essentially no atmosphere. The experimental work presented here evaluates the response of pure sulfur and sulfur concrete subjected to laboratory conditions that approach those expected on the lunar surface, the results suggesting a narrow window of application.

  8. Influence of association of "EVA-NBR" on indirect tensile strength of modified bituminous concrete

    NASA Astrophysics Data System (ADS)

    Chinoun, M.; Soudani, K.; Haddadi, S.

    2016-04-01

    The aim of this work is to contribute to the improvement of the mechanical properties of bituminous concrete by modification of bituminous concrete. In this study, we present the results of the indirect tensile strength "ITS" of modified bituminous concrete by the combination of two modifiers, one is a plastomer EVA (Ethylene Vinyl Acetate) and the other is a industrial waste from the shoe soles grinding NBR (Nitrile Butadiene Rubber) as crumb rubber. To modify the bitumen a wet process was used. The results show that the modification of bitumen by EVA-NBR combination increases their resistance to the indirect traction "ITS" compared to the bituminous concrete control. The mixture of 5% [50% EVA+ 50% NBR] is given the best result among the other associations.

  9. Investigations on Fresh and Hardened Properties of Recycled Aggregate Self Compacting Concrete

    NASA Astrophysics Data System (ADS)

    Revathi, P.; Selvi, R. S.; Velin, S. S.

    2013-09-01

    In the recent years, construction and demolition waste management issues have attracted the attention from researchers around the world. In the present study, the potential usage of recycled aggregate obtained from crushed demolition waste for making self compacting concrete (SCC) was researched. The barriers in promoting the use of recycled material in new construction are also discussed. In addition, the results of an experimental study involving the use of recycled concrete aggregate as coarse aggregates for producing self-compacting concrete to study their flow and strength characteristics are also presented. Five series of mixture were prepared with 0, 25, 50, 75, and 100 % coarse recycled aggregate adopting Nan Su's mix proportioning method. The fresh concrete properties were evaluated through the slump flow, J-ring and V-funnel tests. Compressive and tensile strengths were also determined. The results obtained showed that SCC could be successfully developed by incorporating recycled aggregates.

  10. Symmetric normal mixtures

    NASA Technical Reports Server (NTRS)

    Turmon, Michael

    2004-01-01

    We consider mixture density estimation under the symmetry constraint x = Az for an orthogonal matrix A. This distributional constraint implies a corresponding constraint on the mixture parameters. Focusing on the gaussian case, we derive an expectation-maximization (EM) algorithm to enforce the constraint and show results for modeling of image feature vectors.

  11. Protective coatings for concrete

    SciTech Connect

    NAGY, KATHRYN L.; CYGAN, RANDALL T.; BRINKER, C. JEFFREY; SELLINGER, ALAN

    2000-05-01

    The new two-layer protective coating developed for monuments constructed of limestone or marble was applied to highway cement and to tobermorite, a component of cement, and tested in batch dissolution tests. The goal was to determine the suitability of the protective coating in retarding the weathering rate of concrete construction. The two-layer coating consists of an inner layer of aminoethylaminopropylsilane (AEAPS) applied as a 25% solution in methanol and an outer layer of A2** sol-gel. In previous work, this product when applied to calcite powders, had resulted in a lowering of the rate of dissolution by a factor of ten and was shown through molecular modeling to bind strongly to the calcite surface, but not too strongly so as to accelerate dissolution. Batch dissolution tests at 22 C of coated and uncoated tobermorite (1.1 nm phase) and powdered cement from Gibson Blvd. in Albuquerque indicated that the coating exhibits some protective behavior, at least on short time scales. However, the data suggest that the outer layer of sol-gel dissolves in the high-pH environment of the closed system of cement plus water. Calculated binding configuration and energy of AEAPS to the tobermorite surface suggests that AEAPS is well-suited as the inner layer binder for protecting tobermorite.

  12. Becoming Reactive by Concretization

    NASA Technical Reports Server (NTRS)

    Prieditis, Armand; Janakiraman, Bhaskar

    1992-01-01

    One way to build a reactive system is to construct an action table indexed by the current situation or stimulus. The action table describes what course of action to pursue for each situation or stimulus. This paper describes an incremental approach to constructing the action table through achieving goals with a hierarchical search system. These hierarchies are generated with transformations called concretizations, which add constraints to a problem and which can reduce the search space. The basic idea is that an action for a state is looked up in the action table and executed whenever the action table has an entry for that state; otherwise, a path is found to the nearest (cost-wise in a graph with costweighted arcs) state that has a mappring from a state in the next highest hierarchy. For each state along the solution path, the successor state in the path is cached in the action table entry for that state. Without caching, the hierarchical search system can logarithmically reduce search. When the table is complete the system no longer searches: it simply reacts by proceeding to the state listed in the table for each state. Since the cached information is specific only to the nearest state in the next highest hierarchy and not the goal, inter-goal transfer of reactivity is possible. To illustrate our approach, we show how an implemented hierarchical search system can completely reactive.

  13. Lattice Boltzmann model for the simulation of multicomponent mixtures.

    PubMed

    Arcidiacono, S; Karlin, I V; Mantzaras, J; Frouzakis, C E

    2007-10-01

    A lattice Boltzmann (LB) model for the simulation of realistic multicomponent mixtures is constructed. In the hydrodynamic limit, the LB model recovers the equations of continuum mechanics within the mixture-averaged diffusion approximation. The present implementation can be used to simulate realistic mixtures with arbitrary Schmidt numbers and molecular masses of the species. The model is applied to the mixing of two opposed jets of different concentrations and the results are in excellent agreement with a continuum model. An application to the simulation of mixtures in microflows is also presented. Results compare well with existing kinetic theory predictions of the slip coefficient for mixtures in a Couette flow.

  14. Tensile Bond Strength of Latex-Modified Bonded Concrete Overlays

    NASA Astrophysics Data System (ADS)

    Dubois, Cameron; Ramseyer, Chris

    2010-10-01

    The tensile bond strength of bonded concrete overlays was tested using the in-situ pull-off method described in ASTM C 1583 with the goal of determining whether adding latex to the mix design increases bond strength. One slab of ductile concrete (f'c > 12,000 psi) was cast with one half tined, i.e. roughened, and one half steel-troweled, i.e. smooth. The slab surface was sectioned off and overlay mixtures containing different latex contents cast in each section. Partial cores were drilled perpendicular to the surface through the overlay into the substrate. A tensile loading device applied a direct tensile load to each specimen and the load was increased until failure occurred. The tensile bond strength was then calculated for comparison between the specimens.

  15. Assessment of the recycling potential of fresh concrete waste using a factorial design of experiments.

    PubMed

    Correia, S L; Souza, F L; Dienstmann, G; Segadães, A M

    2009-11-01

    Recycling of industrial wastes and by-products can help reduce the cost of waste treatment prior to disposal and eventually preserve natural resources and energy. To assess the recycling potential of a given waste, it is important to select a tool capable of giving clear indications either way, with the least time and work consumption, as is the case of modelling the system properties using the results obtained from statistical design of experiments. In this work, the aggregate reclaimed from the mud that results from washout and cleaning operations of fresh concrete mixer trucks (fresh concrete waste, FCW) was recycled into new concrete with various water/cement ratios, as replacement of natural fine aggregates. A 3(2) factorial design of experiments was used to model fresh concrete consistency index and hardened concrete water absorption and 7- and 28-day compressive strength, as functions of FCW content and water/cement ratio, and the resulting regression equations and contour plots were validated with confirmation experiments. The results showed that the fresh concrete workability worsened with the increase in FCW content but the water absorption (5-10 wt.%), 7-day compressive strength (26-36 MPa) and 28-day compressive strength (32-44 MPa) remained within the specified ranges, thus demonstrating that the aggregate reclaimed from FCW can be recycled into new concrete mixtures with lower natural aggregate content. PMID:19596189

  16. MASS SPECTROMETRY

    DOEpatents

    Nier, A.O.C.

    1959-08-25

    A voltage switching apparatus is described for use with a mass spectrometer in the concentratron analysis of several components of a gas mixture. The system automatically varies the voltage on the accelerating electrode of the mass spectrometer through a program of voltages which corresponds to the particular gas components under analysis. Automatic operation may be discontinued at any time to permit the operator to manually select any desired predetermined accelerating voltage. Further, the system may be manually adjusted to vary the accelerating voltage over a wide range.

  17. Fly ash-based geopolymer lightweight concrete using foaming agent.

    PubMed

    Al Bakri Abdullah, Mohd Mustafa; Hussin, Kamarudin; Bnhussain, Mohamed; Ismail, Khairul Nizar; Yahya, Zarina; Razak, Rafiza Abdul

    2012-01-01

    In this paper, we report the results of our investigation on the possibility of producing foam concrete by using a geopolymer system. Class C fly ash was mixed with an alkaline activator solution (a mixture of sodium silicate and NaOH), and foam was added to the geopolymeric mixture to produce lightweight concrete. The NaOH solution was prepared by dilute NaOH pellets with distilled water. The reactives were mixed to produce a homogeneous mixture, which was placed into a 50 mm mold and cured at two different curing temperatures (60 °C and room temperature), for 24 hours. After the curing process, the strengths of the samples were tested on days 1, 7, and 28. The water absorption, porosity, chemical composition, microstructure, XRD and FTIR analyses were studied. The results showed that the sample which was cured at 60 °C (LW2) produced the maximum compressive strength for all tests, (11.03 MPa, 17.59 MPa, and 18.19 MPa) for days 1, 7, and 28, respectively. Also, the water absorption and porosity of LW2 were reduced by 6.78% and 1.22% after 28 days, respectively. The SEM showed that the LW2 sample had a denser matrix than LW1. This was because LW2 was heat cured, which caused the geopolymerization rate to increase, producing a denser matrix. However for LW1, microcracks were present on the surface, which reduced the compressive strength and increased water absorption and porosity.

  18. Perception of trigeminal mixtures.

    PubMed

    Filiou, Renée-Pier; Lepore, Franco; Bryant, Bruce; Lundström, Johan N; Frasnelli, Johannes

    2015-01-01

    The trigeminal system is a chemical sense allowing for the perception of chemosensory information in our environment. However, contrary to smell and taste, we lack a thorough understanding of the trigeminal processing of mixtures. We, therefore, investigated trigeminal perception using mixtures of 3 relatively receptor-specific agonists together with one control odor in different proportions to determine basic perceptual dimensions of trigeminal perception. We found that 4 main dimensions were linked to trigeminal perception: sensations of intensity, warmth, coldness, and pain. We subsequently investigated perception of binary mixtures of trigeminal stimuli by means of these 4 perceptual dimensions using different concentrations of a cooling stimulus (eucalyptol) mixed with a stimulus that evokes warmth perception (cinnamaldehyde). To determine if sensory interactions are mainly of central or peripheral origin, we presented stimuli in a physical "mixture" or as a "combination" presented separately to individual nostrils. Results showed that mixtures generally yielded higher ratings than combinations on the trigeminal dimensions "intensity," "warm," and "painful," whereas combinations yielded higher ratings than mixtures on the trigeminal dimension "cold." These results suggest dimension-specific interactions in the perception of trigeminal mixtures, which may be explained by particular interactions that may take place on peripheral or central levels. PMID:25500807

  19. Perception of trigeminal mixtures.

    PubMed

    Filiou, Renée-Pier; Lepore, Franco; Bryant, Bruce; Lundström, Johan N; Frasnelli, Johannes

    2015-01-01

    The trigeminal system is a chemical sense allowing for the perception of chemosensory information in our environment. However, contrary to smell and taste, we lack a thorough understanding of the trigeminal processing of mixtures. We, therefore, investigated trigeminal perception using mixtures of 3 relatively receptor-specific agonists together with one control odor in different proportions to determine basic perceptual dimensions of trigeminal perception. We found that 4 main dimensions were linked to trigeminal perception: sensations of intensity, warmth, coldness, and pain. We subsequently investigated perception of binary mixtures of trigeminal stimuli by means of these 4 perceptual dimensions using different concentrations of a cooling stimulus (eucalyptol) mixed with a stimulus that evokes warmth perception (cinnamaldehyde). To determine if sensory interactions are mainly of central or peripheral origin, we presented stimuli in a physical "mixture" or as a "combination" presented separately to individual nostrils. Results showed that mixtures generally yielded higher ratings than combinations on the trigeminal dimensions "intensity," "warm," and "painful," whereas combinations yielded higher ratings than mixtures on the trigeminal dimension "cold." These results suggest dimension-specific interactions in the perception of trigeminal mixtures, which may be explained by particular interactions that may take place on peripheral or central levels.

  20. Integrated approach for investigating the durability of self-consolidating concrete to sulfate attack

    NASA Astrophysics Data System (ADS)

    Bassuoni, Mohamed Tamer F.

    The growing use of self-consolidating concrete (SCC) in various infrastructure applications exposed to sulfate-rich environments necessitates conducting comprehensive research to evaluate its durability to external sulfate attack. Since the reliability and adequacy of standard sulfate immersion tests have been questioned, the current thesis introduced an integrated testing approach for assessing the durability of a wide scope of SCC mixtures to external sulfate attack. This testing approach involved progressive levels of complexity from single to multiple damage processes. A new series of sulfate attack tests involving multiple field-like parameters and combined damage mechanisms (various cations, controlled pH, wetting-drying, partial immersion, freezing-thawing, and cyclic cold-hot conditions with or without sustained flexural loading) were designed to evaluate the performance (suitability) of the SCC mixtures under various sulfate attack exposure scenarios. The main mixture design variables of SCC included the type of binder (single, binary, ternary and quaternary), air-entrainment, sand-to-aggregate mass ratio and hybrid fibre reinforcement. The comprehensive database and knowledge obtained from this research were used to develop smart models (fuzzy and neuro-fuzzy inference systems) based on artificial-intelligence to evaluate and predict the performance of the SCC mixtures under various sulfate attack exposure regimes implemented in this study. In full immersion tests involving high concentration sodium and magnesium sulfate solutions with controlled pH, the low penetrability of SCC was responsible for the high durability of specimens. Ternary and quaternary cementitious systems with or without limestone materials provided a passivating layer, with or without acid neutralization capacity, which protected SCC from severe damage in the aggressive sulfuric acid and ammonium sulfate solutions. In contrast to conclusions drawn from the sodium sulfate immersion

  1. Solids mass flow determination

    DOEpatents

    Macko, Joseph E.

    1981-01-01

    Method and apparatus for determining the mass flow rate of solids mixed with a transport fluid to form a flowing mixture. A temperature differential is established between the solids and fluid. The temperature of the transport fluid prior to mixing, the temperature of the solids prior to mixing, and the equilibrium temperature of the mixture are monitored and correlated in a heat balance with the heat capacities of the solids and fluid to determine the solids mass flow rate.

  2. SEPARATION OF FLUID MIXTURES

    DOEpatents

    Lipscomb, R.; Craig, A.; Labrow, S.; Dunn, J.F.

    1958-10-28

    An apparatus is presented for separating gaseous mixtures by selectively freezing a constituent of the mixture and subsequently separating the frozen gas. The gas mixture is passed through a cylinder fltted with a cooling jacket, causing one gas to freeze on the walls of the cylinder. A set of scraper blades are provided in the interior of the cyllnder, and as the blades oscillate, the frozen gas is scraped to the bottom of the cylinder. Means are provided for the frozen material to pass into a heating chamber where it is vaporized and the product gas collected.

  3. A comparative study for the concrete compressive strength estimation using neural network and neuro-fuzzy modelling approaches

    NASA Astrophysics Data System (ADS)

    Bilgehan, Mahmut

    2011-03-01

    In this paper, adaptive neuro-fuzzy inference system (ANFIS) and artificial neural network (ANN) model have been successfully used for the evaluation of relationships between concrete compressive strength and ultrasonic pulse velocity (UPV) values using the experimental data obtained from many cores taken from different reinforced concrete structures having different ages and unknown ratios of concrete mixtures. A comparative study is made using the neural nets and neuro-fuzzy (NF) techniques. Statistic measures were used to evaluate the performance of the models. Comparing of the results, it is found that the proposed ANFIS architecture with Gaussian membership function is found to perform better than the multilayer feed-forward ANN learning by backpropagation algorithm. The final results show that especially the ANFIS modelling may constitute an efficient tool for prediction of the concrete compressive strength. Architectures of the ANFIS and neural network established in the current study perform sufficiently in the estimation of concrete compressive strength, and particularly ANFIS model estimates closely follow the desired values. Both ANFIS and ANN techniques can be used in conditions where too many structures are to be examined in a restricted time. The presented approaches enable to practically find concrete strengths in the existing reinforced concrete structures, whose records of concrete mixture ratios are not available or present. Thus, researchers can easily evaluate the compressive strength of concrete specimens using UPV and density values. These methods also contribute to a remarkable reduction in the computational time without any significant loss of accuracy. A comparison of the results clearly shows that particularly the NF approach can be used effectively to predict the compressive strength of concrete using UPV and density values. In addition, these model architectures can be used as a nondestructive procedure for health monitoring of

  4. Nanogranular origin of concrete creep.

    PubMed

    Vandamme, Matthieu; Ulm, Franz-Josef

    2009-06-30

    Concrete, the solid that forms at room temperature from mixing Portland cement with water, sand, and aggregates, suffers from time-dependent deformation under load. This creep occurs at a rate that deteriorates the durability and truncates the lifespan of concrete structures. However, despite decades of research, the origin of concrete creep remains unknown. Here, we measure the in situ creep behavior of calcium-silicate-hydrates (C-S-H), the nano-meter sized particles that form the fundamental building block of Portland cement concrete. We show that C-S-H exhibits a logarithmic creep that depends only on the packing of 3 structurally distinct but compositionally similar C-S-H forms: low density, high density, ultra-high density. We demonstrate that the creep rate ( approximately 1/t) is likely due to the rearrangement of nanoscale particles around limit packing densities following the free-volume dynamics theory of granular physics. These findings could lead to a new basis for nanoengineering concrete materials and structures with minimal creep rates monitored by packing density distributions of nanoscale particles, and predicted by nanoscale creep measurements in some minute time, which are as exact as macroscopic creep tests carried out over years.

  5. Nanogranular origin of concrete creep

    PubMed Central

    Vandamme, Matthieu; Ulm, Franz-Josef

    2009-01-01

    Concrete, the solid that forms at room temperature from mixing Portland cement with water, sand, and aggregates, suffers from time-dependent deformation under load. This creep occurs at a rate that deteriorates the durability and truncates the lifespan of concrete structures. However, despite decades of research, the origin of concrete creep remains unknown. Here, we measure the in situ creep behavior of calcium–silicate–hydrates (C–S–H), the nano-meter sized particles that form the fundamental building block of Portland cement concrete. We show that C–S–H exhibits a logarithmic creep that depends only on the packing of 3 structurally distinct but compositionally similar C–S–H forms: low density, high density, ultra-high density. We demonstrate that the creep rate (≈1/t) is likely due to the rearrangement of nanoscale particles around limit packing densities following the free-volume dynamics theory of granular physics. These findings could lead to a new basis for nanoengineering concrete materials and structures with minimal creep rates monitored by packing density distributions of nanoscale particles, and predicted by nanoscale creep measurements in some minute time, which are as exact as macroscopic creep tests carried out over years. PMID:19541652

  6. Corrosion rate measurements of steel in carbonated concrete

    SciTech Connect

    Saito, H.; Miyata, Y.; Takazawa, H.; Takai, K.; Yamauchi, G.

    1995-12-01

    The polarization resistance of steel bars in concrete after exposure to several environments, as measured by the potential step method, was compared to the actual mass losses of the bars. Each test sample consist of two steel bars embedded in concrete blocks, which were carbonated and exposed to one of several environments, outdoors, indoors, underground, in tunnel, or in water, for one year. Electrochemical measurements of these samples by using the potential step method were carried out at least once a week. The polarization resistance data thus obtained were changed into corrosion currents and mass losses. These calculated mass losses were compared with the actual mass losses of the rods. In some cases, such as indoors, outdoors or in tunnel, the corrosion rate of steel is determined by the amount of water in the concrete. In other cases, such as underground or in water, the oxygen supply determines the corrosion rate. This work demonstrate that in former condition, the potential step method can be use to measure the corrosion rate of steel easily and quickly.

  7. 27. DIVERSION STRUCTURE WITH CONCRETE SIDEWALLS AND CONCRETE CHANNEL BEYOND, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    27. DIVERSION STRUCTURE WITH CONCRETE SIDEWALLS AND CONCRETE CHANNEL BEYOND, A SHORT DISTANCE WEST OF D STREET ABOUT ONE-QUARTER MILE SOUTH OF 9TH AVENUE (SECTION 26). - Highline Canal, Sand Creek Lateral, Beginning at intersection of Peoria Street & Highline Canal in Arapahoe County (City of Aurora), Sand Creek lateral Extends 15 miles Northerly through Araphoe County, City & County of Denver, & Adams County to its end point, approximately 1/4 mile Southest of intersectioin of D Street & Ninth Avenue in Adams County (Rocky Mountain Arsenal, Commerce City Vicinity), Commerce City, Adams County, CO

  8. Perforation of thin unreinforced concrete slabs

    SciTech Connect

    Cargile, J.D.; Giltrud, M.E.; Luk, V.K.

    1993-10-01

    This report discusses fourteen tests which were conducted to investigate the perforation of thin unreinforced concrete slabs. The 4340-steel projectile used in the test series is 50.8 mm in diameter, 355.6 mm in length, has a mass of 2.34 kg. and an ogive nose with caliber radius head of 3. The slabs, contained within steel culverts, are 1.52 m in diameter and consist of concrete with a nominal unconfined compressive strength of 38.2 MPa and maxima aggregate size of 9.5 mm. Slab thicknesses are 284.4, 254.0, 215.9 and 127.0 mm. Tests were conducted at impact velocities of about 313 m/s on all slab thicknesses and about 379 and 471 m/s on the 254.0-mm-thick slab. All tests were conducted at normal incidence to the slab. All tests were conducted at normal incidence to the slab. Information obtained from the tests used to determine the loading (deceleration) on the projectile during the perforation process, the velocity-displacement of the projectile as it perforated the slab, and the projectile position as damage occurred on the backface of the slab. The test projectile behaved essentially as a rigid body for all of the tests.

  9. Temperature-Dependent Thermal Conductivity of High Strength Lightweight Raw Perlite Aggregate Concrete

    NASA Astrophysics Data System (ADS)

    Tandiroglu, Ahmet

    2010-06-01

    Twenty-four types of high strength lightweight concrete have been designed with raw perlite aggregate (PA) from the Erzincan Mollaköy region as new low-temperature insulation material. The effects of the water/cement ratio, the amount of raw PA, and the temperature on high strength lightweight raw perlite aggregate concrete (HSLWPAC) have been investigated. Three empirical equations were derived to correlate the thermal conductivity of HSLWPAC as a function of PA percentage and temperature depending on the water/cement ratio. Experimentally observed thermal conductivities of concrete samples were predicted 92 % of the time for each set of concrete matrices within 97 % accuracy and over the range from 1.457 W · m-1 · K-1 to 1.777 W · m-1 · K-1. The experimental investigation revealed that the usage of raw PA from the Erzincan Mollaköy region in concrete production reduces the concrete unit mass, increases the concrete strength, and furthermore, the thermal conductivity of the concrete has been improved. The proposed empirical correlations of thermal conductivity were considered to be applicable within the range of temperatures 203.15 K ≤ T ≤ 303.15 K in the form of λ = a( PAP b ) + c( T d ).

  10. Fracture Mechanics Modelling of an In Situ Concrete Spalling Experiment

    NASA Astrophysics Data System (ADS)

    Siren, Topias; Uotinen, Lauri; Rinne, Mikael; Shen, Baotang

    2015-07-01

    During the operation of nuclear waste disposal facilities, some sprayed concrete reinforced underground spaces will be in use for approximately 100 years. During this time of use, the local stress regime will be altered by the radioactive decay heat. The change in the stress state will impose high demands on sprayed concrete, as it may suffer stress damage or lose its adhesion to the rock surface. It is also unclear what kind of support pressure the sprayed concrete layer will apply to the rock. To investigate this, an in situ experiment is planned in the ONKALO underground rock characterization facility at Olkiluoto, Finland. A vertical experimental hole will be concreted, and the surrounding rock mass will be instrumented with heat sources, in order to simulate an increase in the surrounding stress field. The experiment is instrumented with an acoustic emission system for the observation of rock failure and temperature, as well as strain gauges to observe the thermo-mechanical interactive behaviour of the concrete and rock at several levels, in both rock and concrete. A thermo-mechanical fracture mechanics study is necessary for the prediction of the damage before the experiment, in order to plan the experiment and instrumentation, and for generating a proper prediction/outcome study due to the special nature of the in situ experiment. The prediction of acoustic emission patterns is made by Fracod 2D and the model later compared to the actual observed acoustic emissions. The fracture mechanics model will be compared to a COMSOL Multiphysics 3D model to study the geometrical effects along the hole axis.

  11. Models for estimation of service life of concrete barriers in low-level radioactive waste disposal

    SciTech Connect

    Walton, J.C.; Plansky, L.E.; Smith, R.W. )

    1990-09-01

    Concrete barriers will be used as intimate parts of systems for isolation of low level radioactive wastes subsequent to disposal. This work reviews mathematical models for estimating the degradation rate of concrete in typical service environments. The models considered cover sulfate attack, reinforcement corrosion, calcium hydroxide leaching, carbonation, freeze/thaw, and cracking. Additionally, fluid flow, mass transport, and geochemical properties of concrete are briefly reviewed. Example calculations included illustrate the types of predictions expected of the models. 79 refs., 24 figs., 6 tabs.

  12. Investigation of Self Consolidating Concrete Containing High Volume of Supplementary Cementitious Materials and Recycled Asphalt Pavement Aggregates

    NASA Astrophysics Data System (ADS)

    Patibandla, Varun chowdary

    The use of sustainable technologies such as supplementary cementitiuous materials (SCMs), and/or recycled materials is expected to positively affect the performance of concrete mixtures. However, it is important to study and qualify such mixtures and check if the required specifications of their intended application are met before they can be implemented in practice. This study presents the results of a laboratory investigation of Self Consolidating concrete (SCC) containing sustainable technologies. A total of twelve concrete mixtures were prepared with various combinations of fly ash, slag, and recycled asphalt pavement (RAP). The mixtures were divided into three groups with constant water to cementitiuous materials ratio of 0.37, and based on the RAP content; 0, 25, and 50% of coarse aggregate replaced by RAP. All mixtures were prepared to achieve a target slump flow equal to or higher than 500 mm (24in). A control mixture for each group was prepared with 100% Portland cement whereas all other mixtures were designed to have up to 70% of portland cement replaced by a combination of supplementary cementitiuous materials (SCMs) such as class C fly ash and granulated blast furnace slag. The properties of fresh concrete investigated in this study include flowability, deformability; filling capacity, and resistance to segregation. In addition, the compressive strength at 3, 14, and 28 days, the tensile strength, and the unrestrained shrinkage up to 80 days was also investigated. As expected the inclusion of the sustainable technologies affected both fresh and hardened concrete properties. Analysis of the experimental data indicated that inclusion of RAP not only reduces the ultimate strength, but it also affected the compressive strength development rate. Moreover, several mixes satisfied compressive strength requirements for pavements and bridges; those mixes included relatively high percentages of SCMs and RAP. Based on the results obtained in this study, it is not

  13. Using a centrifuge for quality control of pre-wetted lightweight aggregate in internally cured concrete

    NASA Astrophysics Data System (ADS)

    Miller, Albert E.

    Early age shrinkage of cementitious systems can result in an increased potential for cracking which can lead to a reduction in service life. Early age shrinkage cracking can be particularly problematic for high strength concretes, which are often specified due to their high strength and low permeability. However, these high strength concretes frequently exhibit a reduction in the internal relative humidity (RH) due to the hydration reaction (chemical shrinkage) and self-desiccation which results in a bulk shrinkage, termed autogenous shrinkage, which is substantial at early ages. Due to the low permeability of these concretes, standard external curing is not always efficient in addressing this reduction in internal RH since the penetration of water can be limited. Internal curing has been developed to reduce autogenous shrinkage. Internally cured mixtures use internal reservoirs filled with fluid (generally water) that release this fluid at appropriate times to counteract the effects of self-desiccation thereby maintaining a high internal RH. Internally cured concrete is frequently produced in North America using pre-wetted lightweight aggregate. One important aspect associated with preparing quality internally cured concrete is being able to determine the absorbed moisture and surface moisture associated with the lightweight aggregate which enables aggregate moisture corrections to be made for the concrete mixture. This thesis represents work performed to develop a test method using a centrifuge to determine the moisture state of pre-wetted fine lightweight aggregate. The results of the test method are then used in a series of worksheets that were developed to assist field technicians when performing the tests and applying the results to a mixture design. Additionally, research was performed on superabsorbent polymers to assess their ability to be used as an internal curing reservoir.

  14. Properties of Portland cement concretes containing pozzolanic admixtures

    NASA Astrophysics Data System (ADS)

    Simmons, D. D.; Pasko, T. J., Jr.; Jones, W. R.

    1981-04-01

    A laboratory comparison was made of the properties of a concrete containing no pozzolan with several mixtures containing pozzolans. Used were a natural pozzolan (Lassenite), two fly ashes of different fineness and low carbon and an amorphous silica fume dust from a metal-producing plant. One cement, one coarse crushed limestone aggregate, and one fine river aggregate were used. Replacing a faster reacting binder with a slower one, produced lower early strengths and adversely affected the properties which are highly dependent on strength. The measures of durability were greatly affected by the air contents and aging or treatment prior to exposure. The amorphous silica fume dust increased the early strengths of a fly ash mixture.

  15. Preliminary report on the correlations among pineal concretions, prostatic calculi and age in human adult males.

    PubMed

    Mori, Ryoichi; Kodaka, Tetsuo; Sano, Tsuneyoshi

    2003-09-01

    By using quantitative image analysis of soft X-ray photographs on the bulk of extracted pineal glands and prostates, we made a preliminary investigation into the correlations among pineal concretions (% by mass), prostatic calculi (% by mass) and age (years) in 40 human adult males, ranging in age from 31 to 95 years (mean (+/-SD) 69.9 +/- 15.2 years), who died and underwent the routine dissection course. The mass concentrations of pineal concretions and prostatic calculi were 17.68 +/- 13.56% (range 0-51.34%) and 0.93 +/- 1.31% (range 0-5.82%), respectively. There was no correlation between the mass concentration of pineal concretions and aging (r = 0.03; P < 1.0). There was no correlation between mass concentration of prostatic calculi and aging (r = 0.28; P < 0.5). No pineal concretions and no prostatic calculi were observed in seven and 10 cases, respectively; in addition, in one case, neither-concretions nor calculi were seen. From such data and from the previously reported suggestion on the counteracting functions between the pineal gland and prostate, a negative correlation between the mass concentrations of pineal concretions and prostatic calculi was expected. This was certainly obtained, but the correlation was low (r = -0.39; P < 0.05). Such a low correlation and no correlations between the concentrations of pineal concretions and aging or between prostatic calculi and aging may have been caused by the examination of relatively older humans. Therefore, further investigations using a number of pair samples collected from males including younger age generations will be necessary. PMID:14527133

  16. Preliminary report on the correlations among pineal concretions, prostatic calculi and age in human adult males.

    PubMed

    Mori, Ryoichi; Kodaka, Tetsuo; Sano, Tsuneyoshi

    2003-09-01

    By using quantitative image analysis of soft X-ray photographs on the bulk of extracted pineal glands and prostates, we made a preliminary investigation into the correlations among pineal concretions (% by mass), prostatic calculi (% by mass) and age (years) in 40 human adult males, ranging in age from 31 to 95 years (mean (+/-SD) 69.9 +/- 15.2 years), who died and underwent the routine dissection course. The mass concentrations of pineal concretions and prostatic calculi were 17.68 +/- 13.56% (range 0-51.34%) and 0.93 +/- 1.31% (range 0-5.82%), respectively. There was no correlation between the mass concentration of pineal concretions and aging (r = 0.03; P < 1.0). There was no correlation between mass concentration of prostatic calculi and aging (r = 0.28; P < 0.5). No pineal concretions and no prostatic calculi were observed in seven and 10 cases, respectively; in addition, in one case, neither-concretions nor calculi were seen. From such data and from the previously reported suggestion on the counteracting functions between the pineal gland and prostate, a negative correlation between the mass concentrations of pineal concretions and prostatic calculi was expected. This was certainly obtained, but the correlation was low (r = -0.39; P < 0.05). Such a low correlation and no correlations between the concentrations of pineal concretions and aging or between prostatic calculi and aging may have been caused by the examination of relatively older humans. Therefore, further investigations using a number of pair samples collected from males including younger age generations will be necessary.

  17. Carbonation and its effects in reinforced concrete

    SciTech Connect

    Broomfield, J.P.

    2000-01-01

    Carbonation is the result of interaction of carbon dioxide (CO{sub 2}) gas in the atmosphere with the alkaline hydroxides in the concrete. CO{sub 2} diffuses through the concrete and rate of movement of the carbonation front roughly follows Fick's law of diffusion. Carbonation depth can be measured by exposing fresh concrete and spraying it with phenolphthalein indicator solution. An example of the test on a reinforced concrete mullion is given.

  18. Influence of Humidity on the Apparent Thermal Conductivity of Concrete Pozzolan

    NASA Astrophysics Data System (ADS)

    Bessenouci, M. Z.; Bibi-Triki, N. E.; Bendimerad, S.; Nakoul, Z.; Khelladi, S.; Hakem, A.

    This work is a study of natural pozzolans as basic components in building materials. It is intended to highlight the thermal advantage of these materials. It is economically advantageous to the pozzolan used in lightweight concrete compositions as a mixture of aggregate pozzolan which provides mechanical strength that complies with current standards. The impact of humidity on the apparent thermal conductivity of concrete pozzolan considered as a porous material requires the best description of the phenomena which surrounds the heat transfer of different phases (liquid- solid-and air). The use of mixed model extended to three phases as a prediction of the thermal conductivity, highlights the importance of the liquid phase

  19. Molecular Survey of Concrete Biofilm Microbial Communities

    EPA Science Inventory

    Although several studies have shown that bacteria can deteriorate concrete structures, there is very little information on the composition of concrete microbial communities. To this end, we studied different microbial communities associated with concrete biofilms using 16S rRNA g...

  20. RADON GENERATION AND TRANSPORT IN AGED CONCRETE

    EPA Science Inventory

    The report gives results of a characterization of radon generation and transport in Florida concretes sampled from 12- to 45-year-old residential slabs. It also compares measurements from old concrete samples to previous measurements on newly poured Florida residential concretes....

  1. 9 CFR 91.26 - Concrete flooring.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 9 Animals and Animal Products 1 2014-01-01 2014-01-01 false Concrete flooring. 91.26 Section 91.26... LIVESTOCK FOR EXPORTATION Inspection of Vessels and Accommodations § 91.26 Concrete flooring. (a) Pens aboard an ocean vessel shall have a 3 inch concrete pavement, proportioned and mixed to give 2000...

  2. 9 CFR 91.26 - Concrete flooring.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Concrete flooring. 91.26 Section 91.26... LIVESTOCK FOR EXPORTATION Inspection of Vessels and Accommodations § 91.26 Concrete flooring. (a) Pens aboard an ocean vessel shall have a 3 inch concrete pavement, proportioned and mixed to give 2000...

  3. Lightweight concrete with enhanced neutron shielding

    DOEpatents

    Brindza, Paul Daniel; Metzger, Bert Clayton

    2016-09-13

    A lightweight concrete containing polyethylene terephthalate in an amount of 20% by total volume. The concrete is enriched with hydrogen and is therefore highly effective at thermalizing neutrons. The concrete can be used independently or as a component of an advanced neutron radiation shielding system.

  4. Evaluation of ilmenite serpentine concrete and ordinary concrete as nuclear reactor shielding

    NASA Astrophysics Data System (ADS)

    Abulfaraj, Waleed H.; Kamal, Salah M.

    1994-07-01

    The present study involves adapting a formal decision methodology to the selection of alternative nuclear reactor concretes shielding. Multiattribute utility theory is selected to accommodate decision makers' preferences. Multiattribute utility theory (MAU) is here employed to evaluate two appropriate nuclear reactor shielding concretes in terms of effectiveness to determine the optimal choice in order to meet the radiation protection regulations. These concretes are Ordinary concrete (O.C.) and Ilmenite Serpentile concrete (I.S.C.). These are normal weight concrete and heavy heat resistive concrete, respectively. The effectiveness objective of the nuclear reactor shielding is defined and structured into definite attributes and subattributes to evaluate the best alternative. Factors affecting the decision are dose received by reactor's workers, the material properties as well as cost of concrete shield. A computer program is employed to assist in performing utility analysis. Based upon data, the result shows the superiority of Ordinary concrete over Ilmenite Serpentine concrete.

  5. Estimating the Concrete Compressive Strength Using Hard Clustering and Fuzzy Clustering Based Regression Techniques

    PubMed Central

    Nagwani, Naresh Kumar; Deo, Shirish V.

    2014-01-01

    Understanding of the compressive strength of concrete is important for activities like construction arrangement, prestressing operations, and proportioning new mixtures and for the quality assurance. Regression techniques are most widely used for prediction tasks where relationship between the independent variables and dependent (prediction) variable is identified. The accuracy of the regression techniques for prediction can be improved if clustering can be used along with regression. Clustering along with regression will ensure the more accurate curve fitting between the dependent and independent variables. In this work cluster regression technique is applied for estimating the compressive strength of the concrete and a novel state of the art is proposed for predicting the concrete compressive strength. The objective of this work is to demonstrate that clustering along with regression ensures less prediction errors for estimating the concrete compressive strength. The proposed technique consists of two major stages: in the first stage, clustering is used to group the similar characteristics concrete data and then in the second stage regression techniques are applied over these clusters (groups) to predict the compressive strength from individual clusters. It is found from experiments that clustering along with regression techniques gives minimum errors for predicting compressive strength of concrete; also fuzzy clustering algorithm C-means performs better than K-means algorithm. PMID:25374939

  6. A study on engineering characteristics of asphalt concrete using filler with recycled waste lime.

    PubMed

    Sung Do, Hwang; Hee Mun, Park; Suk keun, Rhee

    2008-01-01

    This study focuses on determining the engineering characteristics of asphalt concrete using mineral fillers with recycled waste lime, which is a by-product of the production of soda ash (Na(2)CO(3)). The materials tested in this study were made using a 25%, 50%, 75%, and 100% mixing ratio based on the conventional mineral filler ratio to analyze the possibility of using recycled waste lime. The asphalt concretes, made of recycled waste lime, hydrated lime, and conventional asphalt concrete, were evaluated through their fundamental engineering properties such as Marshall stability, indirect tensile strength, resilient modulus, permanent deformation characteristics, moisture susceptibility, and fatigue resistance. The results indicate that the application of recycled waste lime as mineral filler improves the permanent deformation characteristics, stiffness and fatigue endurance of asphalt concrete at the wide range of temperatures. It was also determined that the mixtures with recycled waste lime showed higher resistance against stripping than conventional asphalt concrete. It was concluded from various test results that a waste lime can be used as mineral filler and, especially, can greatly improve the resistance of asphalt concrete to permanent deformation at high temperatures. PMID:17408942

  7. A study on engineering characteristics of asphalt concrete using filler with recycled waste lime.

    PubMed

    Sung Do, Hwang; Hee Mun, Park; Suk keun, Rhee

    2008-01-01

    This study focuses on determining the engineering characteristics of asphalt concrete using mineral fillers with recycled waste lime, which is a by-product of the production of soda ash (Na(2)CO(3)). The materials tested in this study were made using a 25%, 50%, 75%, and 100% mixing ratio based on the conventional mineral filler ratio to analyze the possibility of using recycled waste lime. The asphalt concretes, made of recycled waste lime, hydrated lime, and conventional asphalt concrete, were evaluated through their fundamental engineering properties such as Marshall stability, indirect tensile strength, resilient modulus, permanent deformation characteristics, moisture susceptibility, and fatigue resistance. The results indicate that the application of recycled waste lime as mineral filler improves the permanent deformation characteristics, stiffness and fatigue endurance of asphalt concrete at the wide range of temperatures. It was also determined that the mixtures with recycled waste lime showed higher resistance against stripping than conventional asphalt concrete. It was concluded from various test results that a waste lime can be used as mineral filler and, especially, can greatly improve the resistance of asphalt concrete to permanent deformation at high temperatures.

  8. Concrete Finisher Program. Apprenticeship Training.

    ERIC Educational Resources Information Center

    Alberta Learning, Edmonton. Apprenticeship and Industry Training.

    This document presents information about the apprenticeship training program of Alberta, Canada, in general and the concrete finishing program in particular. The first part of the document discusses the following items: Alberta's apprenticeship and industry training system; the apprenticeship and industry training committee structure; local…

  9. Liquid Coatings for Reducing Corrosion of Steel in Concrete

    NASA Technical Reports Server (NTRS)

    MacDowell, Louis G.; Curran, Joseph

    2003-01-01

    Inorganic coating materials are being developed to slow or stop corrosion of reinforcing steel members inside concrete structures. It is much simpler and easier to use these coating materials than it is to use conventional corrosion-inhibiting systems based on impressed electric currents. Unlike impressed electrical corrosion-inhibiting systems, these coatings do not require continuous consumption of electrical power and maintenance of power-supply equipment. Whereas some conventional systems involve the use of expensive arc-spray equipment to apply the metallic zinc used as the sacrificial anode material, the developmental coatings can be applied by use of ordinary paint sprayers. A coating material of the type under development is formulated as a liquid containing blended metallic particles and/or moisture-attracting compounds. The liquid mixture is sprayed onto a concrete structure. Experiments have shown that even though such a coat resides on the exterior surface, it generates a protective galvanic current that flows to the interior reinforcing steel members. By effectively transferring the corrosion process from the steel reinforcement to the exterior coating, the protective current slows or stops corrosion of the embedded steel. Specific formulations have been found to meet depolarization criteria of the National Association of Corrosion Engineers (NACE) for complete protection of steel reinforcing bars ("rebar") embedded in concrete.

  10. Terahertz spectroscopy of concrete for evaluating the critical hydration level

    NASA Astrophysics Data System (ADS)

    Dash, Jyotirmayee; Ray, Shaumik; Nallappan, Kathirvel; Sasmal, Saptarshi; Pesala, Bala

    2014-03-01

    Concrete, a mixture of cement, coarse aggregate, sand and filler material (if any), is widely used in the construction industry. Cement, mainly composed of Tricalcium Silicate (C3S) and Dicalcium Silicate (C2S) reacts readily with water, a process known as hydration. The hydration process forms a solid material known as hardened cement paste which is mainly composed of Calcium Silicate Hydrate (C-S-H), Calcium Hydroxide and Calcium Carbonate. To quantify the critical hydration level, an accurate and fast technique is highly desired. However, in conventional XRD technique, the peaks of the constituents of anhydrated and hydrated cement cannot be resolved properly, where as Mid-infrared (MIR) spectroscopy has low penetration depth and hence cannot be used to determine the hydration level of thicker concrete samples easily. Further, MIR spectroscopy cannot be used to effectively track the formation of Calcium Hydroxide, a key by-product during the hydration process. This paper describes a promising approach to quantify the hydration dynamics of cement using Terahertz (THz) spectroscopy. This technique has been employed to track the time dependent reaction mechanism of the key constituents of cement that react with water and form the products in the hydrated cement, viz., C-S-H, Calcium Hydroxide and Calcium Carbonate. This study helps in providing an improved understanding on the hydration kinetics of cement and also to optimise the physio-mechanical characteristics of concrete.

  11. Performance evaluation of high modulus asphalt concrete mixes

    NASA Astrophysics Data System (ADS)

    Haritonovs, V.; Tihonovs, J.; Zaumanis, M.

    2016-04-01

    Dolomite is one of the most available sedimentary rocks in the territory of Latvia. Dolomite quarries contain about 1000 million tons of this material. However, according to Latvian Road Specifications, this dolomite cannot be used for average and high intensity roads because of its low quality (mainly, LA index). Therefore, mostly imported magmatic rocks (granite, diabase, gabbro, basalt) or imported dolomite are used which makes asphalt expensive. However, practical experience shows that even with these high quality materials roads exhibit rutting, fatigue and thermal cracks. The aim of the research is to develop a high performance asphalt concrete for base and binder courses using only locally available aggregates. In order to achieve resistance against deformations at a high ambient temperature, a hard grade binder was used. Workability, fatigue and thermal cracking resistance, as well as sufficient water resistance is achieved by low porosity (3-5%) and higher binder content compared to traditional asphalt mixtures. The design of the asphalt includes a combination of empirical and performance based tests, which in laboratory circumstances allow simulating traffic and environmental loads. High performance AC 16 base asphalt concrete was created using local dolomite aggregate with polymer modified (PMB 10/40-65) and hard grade (B20/30) bitumen. The mixtures were specified based on fundamental properties in accordance to EN 13108-1 standard.

  12. Microbiologically induced deterioration of concrete - A Review

    PubMed Central

    Wei, Shiping; Jiang, Zhenglong; Liu, Hao; Zhou, Dongsheng; Sanchez-Silva, Mauricio

    2013-01-01

    Microbiologically induced deterioration (MID) causes corrosion of concrete by producing acids (including organic and inorganic acids) that degrade concrete components and thus compromise the integrity of sewer pipelines and other structures, creating significant problems worldwide. Understanding of the fundamental corrosion process and the causal agents will help us develop an appropriate strategy to minimize the costs in repairs. This review presents how microorganisms induce the deterioration of concrete, including the organisms involved and their colonization and succession on concrete, the microbial deterioration mechanism, the approaches of studying MID and safeguards against concrete biodeterioration. In addition, the uninvestigated research area of MID is also proposed. PMID:24688488

  13. Toxicological evaluation of the effects of waste-to-energy ash-concrete on two marine species

    SciTech Connect

    Hamilton, K.L.; Nelson, W.G.; Curley, J.L. )

    1993-10-01

    The toxicological effects of waste-to-energy ash-concrete on survivorship, growth, and fecundity (end-point parameters) of Mysidopsis bahia and on survivorship and growth of Menidia beryllina were evaluated with the 7-d static-renewal toxicity test. Leachate and elutriate solutions were prepared from experimental ash-concrete test cylinders constructed from concrete with additions of either bottom ash (mix BA), mixed bottom ash and scrubber residue, or mixed bottom ash and fly ash (60:40%, mix BA:FA). Control experiments with concrete (without ash) and pH (7-9.5) were conducted to assess any toxic effects of the stabilization process. pH did not affect end-point parameters of Mysidopsis bahia or Menidia beryllina. However, the 100% elutriate solution made from concrete reduced survivorship of Mysidopsis bahia. For experiments with ash-concrete test cylinders with the BA mixture, 10-d leachate solution reduced survivorship of Mysidopsis bahia and the 100% elutriate solutions reduced survivorship of Mysidopsis bahia and Manidia beryllina. With the BA:SR mixture, the 100 and 50% elutriate solutions reduced survivorship of Menidia beryllina. The BA:FA 10- and 5-d leachate solutions and the 100, 50, and 25% elutriate solutions reduced survivorship of Menidia beryllina. The BA:FA 10- and 5-d leachate solutions and the 100, 50, 25% elutriate solutions reduced survivorship of Mysidopsis bahia.

  14. Prediction of early-age shrinkage cracking in concrete elements

    NASA Astrophysics Data System (ADS)

    Weiss, William Jason

    1999-11-01

    When concrete is prevented from shrinking freely, tensile stresses develop which frequently result in cracking. Cracks in reinforced concrete structures reduce overall durability by allowing the penetration of water and aggressive agents, thereby accelerating the deterioration of the reinforcing steel. Highway pavements, bridge decks, and industrial floors are especially susceptible to this type of deterioration since these structures exhibit high rates of shrinkage and are frequently exposed to aggressive environmental conditions. The objectives of this investigation included the development of experimental procedures for assessing shrinkage cracking potential, the evaluation of mix composition on shrinkage cracking potential, and the development of theoretical models to simulate early-age cracking behavior. Specifically, the influence of a shrinkage-reducing admixture (SRA) was investigated. The shrinkage-reducing admixture substantially reduces free shrinkage and restrained shrinkage cracking while providing similar mechanical properties. An experimental procedure was developed in which a pressurized cylindrical specimen was used to assess tensile creep. Electrical properties were investigated using impedance spectroscopy to evaluate the moisture profiles of drying and wetting concrete. Restrained shrinkage experiments were developed and shrinkage cracking was shown to be size/geometry dependent, even though shrinkage strains and residual stress levels were comparable. A fracture mechanics modeling approach was developed to predict the behavior of a variety of restrained concrete specimens. This modeling approach was used to successfully explain experimental results from a variety of mixture compositions and specimen geometries. The model was used to demonstrate the influence of material and structural properties on the potential for cracking. A favorable correlation was observed between the predictions of the fracture-based model and the experimentally observed

  15. Formwork pressure exerted by self-consolidating concrete

    NASA Astrophysics Data System (ADS)

    Omran, Ahmed Fathy

    Self-consolidating concrete (SCC) is an emerging technology that utilizes flowable concrete that eliminates the need for consolidation. The advantages of SCC lie in a remarkable reduction of the casting time, facilitating the casting of congested and complex structural elements, possibility to reduce labor demand, elimination of mechanical vibrations and noise, improvement of surface appearance, producing a better and premium concrete product. The research focussed on capturing existing knowledge and making recommendations for current practice. An experimental program was undertaken at the Universite de Sherbrooke to evaluate the lateral pressure developed by SCC mixtures. A portable devise (UofS2 pressure column) for measuring and predicting lateral pressure and its rate of decay of SCC was developed and validated. The UofS2 pressure column is cast with 0.5 m high fresh concrete and air pressure is introduced from the top to simulate casting depth up to 13 m. Then, develop and implement test method for field evaluation of relevant plastic and thixotropic properties of SCC that affect formwork pressure were done. Portable vane (PV) test based on the hand-held vane test method used to determine the undrained shear strength property of clay soil was the first setup as well as the inclined plane (IP) test. The IP device involves slumping a small concrete cylinder on a horizontal plate and then lifting up the plate at different durations of rest until the slumped sample starts to move. Identifying role of material constituents, mix design, concrete placement characteristics (casting rate, waiting periods between lifts, and casting depth), temperature, and formwork characteristics that have major influence on formwork pressure exerted by SCC were evaluated in laboratory and validated by actual field measurements. Relating the maximum lateral pressure and its rate of decay to the plastic properties of SCC were established. In the analytical part of the research

  16. Solubilities of carbon dioxide in aqueous mixtures of diethanolamine and 2-amino-2-methyl-1-propanol

    SciTech Connect

    Seo, D.J.; Hong, W.H.

    1996-03-01

    The gas solubility of CO{sub 2} has been measured in aqueous mixtures of diethanolamine and 2-amino-2-methyl-1-propanol at (40, 60, and 80) C and in the pressure range (10 to 300) kPa. The concentrations of the amine mixtures were 6 mass % diethanolamine (DEA) + 24 mass % 2-amino-2-methyl-1-propanol (AMP), 12 mass % DEA + 18 mass % AMP, and 18 mass % DEA + 12 mass % AMP. The solubilities show a systematic change as the composition of the aqueous mixtures varies.

  17. Comparison of various types of stationary phases in non-aqueous reversed-phase high-performance liquid chromatography-mass spectrometry of glycerolipids in blackcurrant oil and its enzymatic hydrolysis mixture.

    PubMed

    Lísa, Miroslav; Holcapek, Michal; Sovová, Helena

    2009-11-20

    The selection of column packing during the development of high-performance liquid chromatography method is a crucial step to achieve sufficient chromatographic resolution of analyzed species in complex mixtures. Various stationary phases are tested in this paper for the analysis of complex mixture of triacylglycerols (TGs) in blackcurrant oil using non-aqueous reversed-phase (NARP) system with acetonitrile-2-propanol mobile phase. Conventional C(18) column in the total length of 45 cm is used for the separation of TGs according to their equivalent carbon number, the number and positions of double bonds and acyl chain lengths. The separation of TGs and their more polar hydrolysis products after the partial enzymatic hydrolysis of blackcurrant oil in one chromatographic run is achieved using conventional C(18) column. Retention times of TGs are reduced almost 10 times without the loss of the chromatographic resolution using ultra high-performance liquid chromatography with 1.7 microm C(18) particles. The separation in NARP system on C(30) column shows an unusual phenomenon, because the retention order of TGs changes depending on the column temperature, which is reported for the first time. The commercial monolithic column modified with C(18) is used for the fast analysis of TGs to increase the sample throughput but at cost of low resolution.

  18. Feasibility of using phase change materials to control the heat of hydration in massive concrete structures.

    PubMed

    Choi, Won-Chang; Khil, Bae-Soo; Chae, Young-Seok; Liang, Qi-Bo; Yun, Hyun-Do

    2014-01-01

    This paper presents experimental results that can be applied to select a possible phase change material (PCM), such as a latent heat material (LHM), to control the hydration heat in mass concrete structures. Five experimental tests (microconduction, simplified adiabatic temperature rise, heat, and compressive strength tests) were conducted to select the most desirable LHM out of seven types of inorganic PCM used in cement mortar and to determine the most suitable mix design. The results of these experimental tests were used to assess the feasibility of using PCM to reduce hydration heat in mass concrete that was examined. The experimental results show that cement mortar containing barium- [Ba(OH)2 · 8H2O] based PCM has the lowest amount of total hydration heat of the cement pastes. The barium-based PCM provides good latent heat properties that help to prevent volume change and microcracks caused by thermal stress in mass concrete.

  19. Reinforcement of asphalt concrete pavement by segments of exhausted fiber used for sorption of oil spill

    NASA Astrophysics Data System (ADS)

    Lukashevich, V. N.; Efanov, I. N.

    2015-01-01

    The paper is aimed at construction of the experimental road pavement made of dispersed reinforced asphalt concrete. Electronic paramagnetic resonance, infrared spectroscopy and fluorescent bitumen studies were used to prove that disperse reinforcement of asphalt concrete mixtures with fibers of exhausted sorbents reduce the selective filtration of low polymeric fractions of petroleum bitumen and improve its properties in the adsorption layer. Sesquioxides are neutralized as catalysts aging asphalt binder. This leads to improvement in the elasticity of bitumen films at low temperatures and provide better crack resistance of coatings to reduce the intensity of the aging of asphalt binder, and, therefore, to increase the durability of road pavements. The experimental road pavement made of dispersed reinforced asphalt concrete operated during 4 years and demonstrated better transport- performance properties in comparison with the analogue pavements.

  20. Evaluation of non-metallic fiber reinforced concrete in new full depth pcc pavements. Final report

    SciTech Connect

    Ramakrishnan, V.; Tolmare, N.S.

    1998-12-30

    This final report presents the construction and performance evaluation of a new full depth pavement, constructed with a new type non-metallic fiber reinforced concrete (NMFRC). The mixture proportions used, the quality control tests conducted for the evaluation of the fresh and hardened concrete properties, the procedure used for mixing, transporting, placing, consolidating, finishing, and curing of the concrete are described. Periodic inspection of the full depth pavement was done and this report includes the results of these inspections. The feasibility of using this NMFRC in the construction of highway structures has been discussed. The new NMFRC with enhanced fatigue, impact resistance, modulus of rupture, ductility and toughness properties is suitable for the construction of full depth pavements. However, a life-cycle cost analysis shows that NMFRC is not a favorable choice, because of it`s high initial cost.

  1. Development of lightweight concrete mixes for construction industry at the state of Arkansas

    NASA Astrophysics Data System (ADS)

    Almansouri, Mohammed Abdulwahab

    As the construction industry evolved, the need for more durable, long lasting infrastructure increased. Therefore, more efforts have been put to find new methods to improve the properties of the concrete to prolong the service life of the structural elements. One of these methods is the use of lightweight aggregate as an internal curing agent to help reducing self-desiccation and shrinkage. This research studied the effects of using locally available lightweight aggregate (expanded clay), as a partial replacement of normal weight aggregate in the concrete matrix. The concrete mixtures contained lightweight aggregate with a replacement percentage of 12.5, 25, 37.5, and 50 percent by volume. Fresh properties as well as compressive strength, modulus of rupture, and drying shrinkage were measured. While was effective in reducing drying shrinkage, the use of lightweight aggregate resulted in slightly reducing both the compressive strength and modulus of rupture.

  2. Relativistic mixtures of charged and uncharged particles

    SciTech Connect

    Kremer, Gilberto M.

    2014-01-14

    Mixtures of relativistic gases within the framework of Boltzmann equation are analyzed. Three systems are considered. The first one refers to a mixture of uncharged particles by using Grad’s moment method, where the relativistic mixture is characterized by the moments of the distribution functions: particle four-flows, energy-momentum tensors, and third-order moment tensors. In the second Fick’s law for a mixture of relativistic gases of non-disparate rest masses in a Schwarzschild metric are derived from an extension of Marle and McCormack model equations applied to a relativistic truncated Grad’s distribution function, where it is shown the dependence of the diffusion coefficient on the gravitational potential. The third one consists in the derivation of the relativistic laws of Ohm and Fourier for a binary mixtures of electrons with protons and electrons with photons subjected to external electromagnetic fields and in presence of gravitational fields by using the Anderson and Witting model of the Boltzmann equation.

  3. Fracture properties of lightweight concrete

    SciTech Connect

    Chang, T.P.; Shieh, M.M.

    1996-02-01

    This study presents the experimental results of fracture properties of concrete incorporating two kinds of domestic lightweight aggregate (LWA) manufactured through either a cold-bonding or a sintering process. The cold-bonded aggregates were mainly made of pulverized fly-ash through a cold-pelletization process at ambient temperature, while the sintered aggregates were made of clay and shale expanded by heat at a temperature near 1,200 C. Experimental results show that the 28-day compressive strengths of {phi} 100 x 200 mm cylindrical concrete specimen made of those LWAs range from 30.1 (sintered) to 33.9 MPa (cold-bonded). By means of size effect law, it is found that the fracture energies, G{sub f}, were 34.42 N/m (sintered) and 37.2 N/m (cold-bonded), respectively.

  4. Radionuclide Retention in Concrete Wasteforms

    SciTech Connect

    Bovaird, Chase C.; Jansik, Danielle P.; Wellman, Dawn M.; Wood, Marcus I.

    2011-09-30

    Assessing long-term performance of Category 3 waste cement grouts for radionuclide encasement requires knowledge of the radionuclide-cement interactions and mechanisms of retention (i.e., sorption or precipitation); the mechanism of contaminant release; the significance of contaminant release pathways; how wasteform performance is affected by the full range of environmental conditions within the disposal facility; the process of wasteform aging under conditions that are representative of processes occurring in response to changing environmental conditions within the disposal facility; the effect of wasteform aging on chemical, physical, and radiological properties; and the associated impact on contaminant release. This knowledge will enable accurate prediction of radionuclide fate when the wasteforms come in contact with groundwater. The information present in the report provides data that (1) measures the effect of concrete wasteform properties likely to influence radionuclide migration; and (2) quantifies the rate of carbonation of concrete materials in a simulated vadose zone repository.

  5. Sodium Exposure Tests on Limestone Concrete Used as Sacrificial Protection Layer in FBR

    SciTech Connect

    Parida, F.C.; Das, S.K.; Sharma, A.K.; Rao, P.M.; Ramesh, S.S.; Somayajulu, P.A.; Malarvizhi, B.; Kasinathan, N.

    2006-07-01

    Hot sodium coming in contact with structural concrete in case of sodium leak in FBR system cause damage as a result of thermo-chemical attack by burning sodium. In addition, release of free and bound water from concrete leads to generation of hydrogen gas, which is explosive in nature. Hence limestone concrete, as sacrificial layer on the structural concrete in FBR, needs to be qualified. Four concrete blocks of dimension 600 mm x 600 mm x 300 mm with 300 mm x 300 mm x 150 mm cavity were cast and subjected to controlled sodium exposure tests. They have composition of ordinary portland cement, water, fine and coarse aggregate of limestone in the ratio of 1: 0.58: 2.547: 3.817. These blocks were subjected to preliminary inspection by ultrasonic pulse velocity technique and rebound hammer tests. Each block was exposed for 30 minutes to about 12 kg of liquid sodium ({approx} 120 mm liquid column) at 550 deg. C in open air, after which sodium was sucked back from the cavity of the concrete block into a sodium tank. On-line temperature monitoring was carried out at strategic locations of sodium pool and concrete block. After removing sodium from the cavity and cleaning the surfaces, rebound hammer testing was carried out on each concrete block at the same locations where data were taken earlier at pre-exposed stage. The statistical analysis of rebound hammer data revealed that one of the concrete block alone has undergone damage to the extent of 16%. The loss of mass occurred for all the four blocks varied from 0.6 to 2.4% due to release of water during the test duration. Chemical analysis of sodium in concrete samples collected from cavity floor of each block helped in generation of depth profiles of sodium monoxide concentration for each block. From this it is concluded that a bulk penetration of sodium up to 30 mm depth has taken place. However it was also observed that at few local spots, sodium penetrated into concrete up to 50 mm. Cylindrical core samples of 50 mm

  6. Aerosol and melt chemistry in the ACE molten core-concrete interaction experiments

    SciTech Connect

    Fink, J.K.; Thompson, D.H.; Spencer, B.W.; Sehgal, B.R.

    1995-01-01

    Experimental results are discussed from the internationally sponsored Advanced Containment Experiments (ACE) Program on the melt behavior and aerosols released during the interaction of molten reactor core material with concrete. A broad range of parameters were addressed in the experimental program: Seven large-scale tests were performed using four types of concrete (siliceous, limestone/sand, serpentine, and limestone) and a range of metal oxidations for both boiling water and pressurized waster reactor core debris. The release aerosols contained mainly constitutents of the concrete. In the tests with metal and limestone/sand siliceous concrete, silicon compounds comprised 50% or more of the aerosol mass. Releases of uranium and low-volatility fission-product elements were small in all tests. Releases of tellurium and neutron absorber materials (silver, indium, and boron from boron carbide) were high.

  7. The influence of high performance matrices on fracture behavior of concrete

    NASA Astrophysics Data System (ADS)

    Lertwattanaruk, Pusit

    Modification of cement matrices by the addition of micro particle pozzolanic materials such as silica fume and fly ash is known to improve the strength of concrete, but its contributions to fracture behavior remains unclear. In this study, the influence of replacing cement by silica fume and fly ash on the cement matrix-coarse aggregate interfacial bond, compressive stress-strain behavior and fracture behavior of concrete is investigated. While the linear elastic fracture mechanics (LEFM) concept is not appropriate for concrete, a non-linear fracture model based on the load vs. load-line deflection and the load vs. crack-mouth-opening displacement (CMOD) responses of the three-point bend tests on notched beams is proposed and validated. Instead of using the LEFM based Two-Parameter Fracture Model that cannot adequately describes fracture processes in concrete, the proposed model is capable of generating the load vs. crack growth curve and the fracture resistance curve, and seems to be more appropriate for studying fracture behavior of concrete. Incorporating silica fume in concrete mixture is found to have many beneficial effects on cement matrix-coarse aggregate interface, but less likely to improve the toughness of the cement matrix itself. The enhanced interfacial bond due to silica fume produces a more homogeneous concrete, which is responsible for the high strength, but more brittle concrete. It is shown that improving interfacial bond has positive effect on the pre-peak fracture behavior of concrete (e.g. the critical energy release rate, GC), but does not necessarily improve the overall fracture behavior (e.g. the fracture energy, GF, and the brittleness). In this study, coal fly ashes were fractionated into various size ranges by the air classifier method. It is found that replacing cement by very fine fly ash (with average particle size less than 3 microns) can enhance both the toughness of cement matrix and the interfacial bond, which results in high

  8. Equations for nonbonded concrete overlays

    NASA Astrophysics Data System (ADS)

    Chou, Y. T.

    1985-09-01

    The nature of the design equations for the nonbonded concrete overlays currently used by the US Army Corps of Engineers was examined and the original source of the equation was also examined. Using simple mechanics, new overlay equations were developed which are suitable for different thicknesses and elastic properties in the overlay and base concrete slabs. The difference in the computed overlay thickness between the new and existing equations is not large when the overlay thickness is equal to or greater than the base slab. The difference can become excessive when the overlay thickness is much less than that of the base slab. The new equations were compared with the finite element computer program for concrete overlays with various combinations of slab thickness, elastic property, and subgrade modulus. The comparisons were very favorable, indicating that the overlay equations developed in this report are analytically correct. It was difficult to judge whether the new equations are superior to the existing equation. This conclusion was expected because for all the seven test sections analyzed, the overlay thicknesses were either equal to or greater than those of the base slabs.

  9. Laser ablation studies of concrete

    SciTech Connect

    Savina, M.; Xu, Z.; Wang, Y.; Reed, C.; Pellin, M.

    1999-10-20

    Laser ablation was studied as a means of removing radioactive contaminants from the surface and near-surface regions of concrete. The authors present the results of ablation tests on cement and concrete samples using a 1.6 kW pulsed Nd:YAG laser with fiber optic beam delivery. The laser-surface interaction was studied using cement and high density concrete as targets. Ablation efficiency and material removal rates were determined as functions of irradiance and pulse overlap. Doped samples were also ablated to determine the efficiency with which surface contaminants were removed and captured in the effluent. The results show that the cement phase of the material melts and vaporizes, but the aggregate portion (sand and rock) fragments. The effluent consists of both micron-size aerosol particles and chunks of fragmented aggregate material. Laser-induced optical emission spectroscopy was used to analyze the surface during ablation. Analysis of the effluent showed that contaminants such as cesium and strontium were strongly segregated into different regions of the particle size distribution of the aerosol.

  10. Radionuclide Migration through Sediment and Concrete: 16 Years of Investigations

    SciTech Connect

    Golovich, Elizabeth C.; Mattigod, Shas V.; Snyder, Michelle MV; Powers, Laura; Whyatt, Greg A.; Wellman, Dawn M.

    2014-11-01

    The Waste Management Project provides safe, compliant, and cost-effective waste management services for the Hanford Site and the U.S. Department of Energy (DOE) complex. Part of these services includes safe disposal of low-level waste and mixed low-level waste at the Hanford Low-Level Waste Burial Grounds in accordance with the requirements of DOE Order 435.1, Radioactive Waste Management. To partially satisfy these requirements, performance assessment analyses were completed and approved. DOE Order 435.1 also requires continuing data collection to increase confidence in the critical assumptions used in these analyses to characterize the operational features of the disposal facility that are relied on to satisfy the performance objectives identified in the order. Cement-based solidification and stabilization is considered for hazardous waste disposal because it is easily done and cost-efficient. One critical assumption is that concrete will be used as a waste form or container material at the Hanford Site to control and minimize the release of radionuclide constituents in waste into the surrounding environment. Concrete encasement would contain and isolate the waste packages from the hydrologic environment and act as an intrusion barrier. Any failure of concrete encasement may result in water intrusion and consequent mobilization of radionuclides from the waste packages. The radionuclides iodine-129, selenium-75, technetium-99, and uranium-238 have been identified as long-term dose contributors (Mann et al. 2001; Wood et al. 1995). Because of their anionic nature in aqueous solutions, these constituents of potential concern may be released from the encased concrete by mass flow and/or diffusion and migrate into the surrounding subsurface environment (Serne et al. 1989; 1992; 1993a, b; 1995). Therefore, it is necessary to assess the performance of the concrete encasement structure and the ability of the surrounding soil to retard radionuclide migration. Each of the

  11. Fly Ash-based Geopolymer Lightweight Concrete Using Foaming Agent

    PubMed Central

    Al Bakri Abdullah, Mohd Mustafa; Hussin, Kamarudin; Bnhussain, Mohamed; Ismail, Khairul Nizar; Yahya, Zarina; Razak, Rafiza Abdul

    2012-01-01

    In this paper, we report the results of our investigation on the possibility of producing foam concrete by using a geopolymer system. Class C fly ash was mixed with an alkaline activator solution (a mixture of sodium silicate and NaOH), and foam was added to the geopolymeric mixture to produce lightweight concrete. The NaOH solution was prepared by dilute NaOH pellets with distilled water. The reactives were mixed to produce a homogeneous mixture, which was placed into a 50 mm mold and cured at two different curing temperatures (60 °C and room temperature), for 24 hours. After the curing process, the strengths of the samples were tested on days 1, 7, and 28. The water absorption, porosity, chemical composition, microstructure, XRD and FTIR analyses were studied. The results showed that the sample which was cured at 60 °C (LW2) produced the maximum compressive strength for all tests, (11.03 MPa, 17.59 MPa, and 18.19 MPa) for days 1, 7, and 28, respectively. Also, the water absorption and porosity of LW2 were reduced by 6.78% and 1.22% after 28 days, respectively. The SEM showed that the LW2 sample had a denser matrix than LW1. This was because LW2 was heat cured, which caused the geopolymerization rate to increase, producing a denser matrix. However for LW1, microcracks were present on the surface, which reduced the compressive strength and increased water absorption and porosity. PMID:22837687

  12. Fly ash-based geopolymer lightweight concrete using foaming agent.

    PubMed

    Al Bakri Abdullah, Mohd Mustafa; Hussin, Kamarudin; Bnhussain, Mohamed; Ismail, Khairul Nizar; Yahya, Zarina; Razak, Rafiza Abdul

    2012-01-01

    In this paper, we report the results of our investigation on the possibility of producing foam concrete by using a geopolymer system. Class C fly ash was mixed with an alkaline activator solution (a mixture of sodium silicate and NaOH), and foam was added to the geopolymeric mixture to produce lightweight concrete. The NaOH solution was prepared by dilute NaOH pellets with distilled water. The reactives were mixed to produce a homogeneous mixture, which was placed into a 50 mm mold and cured at two different curing temperatures (60 °C and room temperature), for 24 hours. After the curing process, the strengths of the samples were tested on days 1, 7, and 28. The water absorption, porosity, chemical composition, microstructure, XRD and FTIR analyses were studied. The results showed that the sample which was cured at 60 °C (LW2) produced the maximum compressive strength for all tests, (11.03 MPa, 17.59 MPa, and 18.19 MPa) for days 1, 7, and 28, respectively. Also, the water absorption and porosity of LW2 were reduced by 6.78% and 1.22% after 28 days, respectively. The SEM showed that the LW2 sample had a denser matrix than LW1. This was because LW2 was heat cured, which caused the geopolymerization rate to increase, producing a denser matrix. However for LW1, microcracks were present on the surface, which reduced the compressive strength and increased water absorption and porosity. PMID:22837687

  13. Glass fiber reinforced concrete for terrestrial photovoltaic arrays

    NASA Technical Reports Server (NTRS)

    Maxwell, H.

    1979-01-01

    The use of glass-fiber-reinforced concrete (GRC) as a low-cost structural substrate for terrestrial solar cell arrays is discussed. The properties and fabrication of glass-reinforced concrete structures are considered, and a preliminary design for a laminated solar cell assembly built on a GRC substrate is presented. A total cost for such a photovoltaic module, composed of a Korad acrylic plastic film front cover, an aluminum foil back cover, an ethylene/vinyl acetate pottant/adhesive and a cotton fabric electrical isolator in addition to the GRC substrate, of $9.42/sq m is projected, which is less than the $11.00/sq m cost goal set by the Department of Energy. Preliminary evaluations are concluded to have shown the design capabilities and cost effectiveness of GRC; however, its potential for automated mass production has yet to be evaluated.

  14. Beneficial Use of Carbon Dioxide in Precast Concrete Production

    SciTech Connect

    Shao, Yixin

    2014-06-26

    The feasibility of using carbon dioxide as feedstock in precast concrete production is studied. Carbon dioxide reacts with calcium compounds in concrete, producing solid calcium carbonates in binding matrix. Two typical precast products are examined for their capacity to store carbon dioxide during the production. They are concrete blocks and fiber-cement panels. The two products are currently mass produced and cured by steam. Carbon dioxide can be used to replace steam in curing process to accelerate early strength, improve the long-term durability and reduce energy and emission. For a reaction within a 24-hour process window, the theoretical maximum possible carbon uptake in concrete is found to be 29% based on cement mass in the product. To reach the maximum uptake, a special process is developed to promote the reaction efficiency to 60-80% in 4-hour carbon dioxide curing and improve the resistance to freeze-thaw cycling and sulfate ion attack. The process is also optimized to meet the project target of $10/tCO2 in carbon utilization. By the use of self-concentrating absorption technology, high purity CO2 can be produced at a price below $40/t. With low cost CO2 capture and utilization technologies, it is feasible to establish a network for carbon capture and utilization at the vicinity of carbon sources. If all block produces and panel producers in United States could adopt carbon dioxide process in their production in place of steam, carbon utilization in these two markets alone could consume more than 2 Mt CO2/year. This capture and utilization process can be extended to more precast products and will continue for years to come.

  15. Influence of the porosity on the ²²²Rn exhalation rate of concrete.

    PubMed

    de Jong, Peter; van Dijk, Willem; de Rooij, Mario

    2011-02-01

    The composition of 23 concrete mixtures was varied in five separate series to evaluate the influence of porosity on the ²²²Rn exhalation rate. In each series, a range in porosities is obtained by varying (1) the amount of cement, (2) type of cement (Portland or blast furnace slag cement), (3) the amount of water at a fixed cement level, (4) addition of an air entraining agent, or (5) the amount of recycled aggregates. The porosities ranged from 1% to 16%. The ²²²Rn exhalation rate is normalized to the ²²⁶Ra activity concentration and expressed as the ²²²Rn release factor to eliminate the effect of differences in ²²⁶Ra activity concentrations among the various concrete mixtures. Since most ²²²Rn originates from the cement, a ²²²Rn release factor based on the amount of ²²⁶Ra introduced by the cements appeared to be more adequate. Although the methods to attain the porosities in the concrete mixtures differ widely, this cement-related factor corresponds well with the capillary porosity of the mixtures. Since the water-to-cement ratio of the fresh paste is a good indicator of the capillary porosity, this is the guiding factor in the fabrication of concretes low in ²²²Rn exhalation. The lower the water-to-cement ratio, the less capillary pore area will be available from which ²²²Rn can emanate from the mineral matrix into the pore system. The good correlation between the cement-based ²²²Rn release factor and literature data on the internal capillary pore area support the results of this study. PMID:21399427

  16. Radiation shielding concrete made of Basalt aggregates.

    PubMed

    Alhajali, S; Yousef, S; Kanbour, M; Naoum, B

    2013-04-01

    In spite of the fact that Basalt is a widespread type of rock, there is very little available information on using it as aggregates for concrete radiation shielding. This paper investigates the possibility of using Basalt for the aforementioned purpose. The results have shown that Basalt could be used successfully for preparing radiation shielding concrete, but some attention should be paid to the choice of the suitable types of Basalt and for the neutron activation problem that could arise in the concrete shield.

  17. Phase 2 microwave concrete decontamination results

    SciTech Connect

    White, T.L.; Foster, D. Jr.; Wilson, C.T.; Schaich, C.R.

    1995-04-01

    The authors report on the results of the second phase of a four-phase program at Oak Ridge National Laboratory to develop a system to decontaminate concrete using microwave energy. The microwave energy is directed at the concrete surface through the use of an optimized wave guide antenna, or applicator, and this energy rapidly heats the free water present in the interstitial spaces of the concrete matrix. The resulting steam pressure causes the surface to burst in much the same way popcorn pops in a home microwave oven. Each steam explosion removes several square centimeters of concrete surface that are collected by a highly integrated wave guide and vacuum system. The authors call this process the microwave concrete decontamination, or MCD, process. In the first phase of the program the principle of microwaves concrete removal concrete surfaces was demonstrated. In these experiments, concrete slabs were placed on a translator and moved beneath a stationary microwave system. The second phase demonstrated the ability to mobilize the technology to remove the surfaces from concrete floors. Area and volume concrete removal rates of 10.4 cm{sup 2}/s and 4.9 cm{sup 3}/S, respectively, at 18 GHz were demonstrated. These rates are more than double those obtained in Phase 1 of the program. Deeper contamination can be removed by using a longer residence time under the applicator to create multiple explosions in the same area or by taking multiple passes over previously removed areas. Both techniques have been successfully demonstrated. Small test sections of painted and oil-soaked concrete have also been removed in a single pass. Concrete with embedded metal anchors on the surface has also been removed, although with some increased variability of removal depth. Microwave leakage should not pose any operational hazard to personnel, since the observed leakage was much less than the regulatory standard.

  18. Analyzing environmental and structural charactersitics of concrete for carbon mitigation and climate adaptation in urban areas: A case study in Rajkot, India

    NASA Astrophysics Data System (ADS)

    Solis, Andrea Valdez

    Increasing temperatures, varying rain events accompanied with flooding or droughts coupled with increasing water demands, and decreasing air quality are just some examples of stresses that urban systems face with the onset of climate change and rapid urbanization. Literature suggests that greenhouse gases are a leading cause of climate change and are of a result of anthropogenic activities such as infrastructure development. Infrastructure development is heavily dependent on the production of concrete. Yet, concrete can contribute up to 7% of total CO29 emissions globally from cement manufacturing alone. The goal of this dissertation was to evaluate current concrete technologies that could contribute to carbon mitigation and climate adaptation in cities. The objectives used to reach the goal of the study included (1) applying a material flow and life cycle analysis (MFA-LCA) to determine the environmental impacts of pervious and high volume fly ash (HVFA) concrete compared to ordinary portland cement (OPC) concrete in a developing country; (2) performing a comparative assessment of pervious concrete mixture designs for structural and environmental benefits across the U.S. and India; and (3) Determining structural and durability benefits from HVFA concrete mixtures when subjected to extreme hot weather conditions (a likely element of climate change). The study revealed that cities have a choice in reducing emissions, improving stormwater issues, and developing infrastructure that can sustain higher temperatures. Pervious and HVFA concrete mixtures reduce emissions by 21% and 47%, respectively, compared to OPC mixtures. A pervious concrete demonstration in Rajkot, India showed improvements in water quality (i.e. lower levels of nitrogen by as much as 68% from initial readings), and a reduction in material costs by 25%. HVFA and OPC concrete mixtures maintained compressive strengths above a design strength of 27.6 MPa (4000 psi), achieved low to moderate permeability

  19. Development and construction of low-cracking high-performance concrete (LC-HPC) bridge decks: Free shrinkage tests, restrained ring tests, construction experience, and crack survey results

    NASA Astrophysics Data System (ADS)

    Yuan, Jiqiu

    2011-12-01

    The development, construction, and evaluation of low-cracking high-performance concrete (LC-HPC) bridge decks are described based on laboratory test results and experiences gained during the construction of 13 LC-HPC bridge decks in Kansas, along with another deck bid under the LC-HPC specifications but for which the owner did not enforce the specification. This study is divided into four parts covering (1) an evaluation of the free shrinkage properties of LC-HPC candidate mixtures, (2) an investigation of the relationship between the evaporable water content in the cement paste and the free shrinkage of concrete, (3) a study of the restrained shrinkage performance of concrete using restrained ring tests, and (4) a description of the construction and preliminary evaluation of LC-HPC and control bridge decks constructed in Kansas. The first portion of the study involves evaluating the effects of the duration of curing, fly ash, and a shrinkage reducing admixture (SRA) on the free-shrinkage characteristics of concrete mixtures. The results indicate that an increase of curing period reduces free shrinkage. With 7 days of curing, concretes containing fly ash as a partial replacement for cement exhibit higher free shrinkage than concretes with 100% portland cement. When the curing period is increased to 14, 28, and 56 days, the adverse effect of adding fly ash on free shrinkage is minimized and finally reversed. The addition of an SRA significantly reduces free shrinkage for both the 100% portland cement mixture and the mixture containing fly ash. The second portion of the study investigates the relationship between the evaporable water content in the cement paste and the free shrinkage of concrete. A linear relationship between free shrinkage and evaporable water content in the cement paste is observed. For a given mixture, specimens cured for a longer period contain less evaporable water and exhibit lower free shrinkage and less weight loss in the free shrinkage

  20. Alkali-silica reactivity of expanded glass granules in structure of lightweight concrete

    NASA Astrophysics Data System (ADS)

    Bumanis, G.; Bajare, D.; Locs, J.; Korjakins, A.

    2013-12-01

    Main component in the lightweight concrete, which provides its properties, is aggregate. A lot of investigations on alkali silica reaction (ASR) between cement and lightweight aggregates have been done with their results published in the academic literature. Whereas expanded glass granules, which is relatively new product in the market of building materials, has not been a frequent research object. Therefore lightweight granules made from waste glass and eight types of cement with different chemical and mineralogical composition were examined in this research. Expanded glass granules used in this research is commercially available material produced by Penostek. Lightweight concrete mixtures were prepared by using commercial chemical additives to improve workability of concrete. The aim of the study is to identify effect of cement composition to the ASR reaction which occurs between expanded glass granules and binder. Expanded glass granules mechanical and physical properties were determined. In addition, properties of fresh and hardened concrete were determined. The ASR test was processed according to RILEM AAR-2 testing recommendation. Tests with scanning electron microscope and microstructural investigations were performed for expanded glass granules and hardened concrete specimens before and after exposing them in alkali solution.

  1. Economic analysis of recycling contaminated concrete

    SciTech Connect

    Stephen, A.; Ayers, K.W.; Boren, J.K.; Parker, F.L.

    1997-02-01

    Decontamination and Decommissioning activities in the DOE complex generate large volumes of radioactively contaminated and uncontaminated concrete. Currently, this concrete is usually decontaminated, the contaminated waste is disposed of in a LLW facility and the decontaminated concrete is placed in C&D landfills. A number of alternatives to this practice are available including recycling of the concrete. Cost estimates for six alternatives were developed using a spreadsheet model. The results of this analysis show that recycling alternatives are at least as economical as current practice.

  2. Proceedings of the concrete decontamination workshop

    SciTech Connect

    Halter, J.M.; Sullivan, R.G.; Currier, A.J.

    1980-05-28

    Fourteen papers were presented. These papers describe concrete surface removal methods and equipment, as well as experiences in decontaminating and removing both power and experimental nuclear reactors.

  3. Pentek concrete scabbling system: Baseline report; Summary

    SciTech Connect

    1997-07-31

    The Pentek concrete scabbling system consists of the MOOSE{reg_sign} scabbler, the SQUIRREL{reg_sign}-I and SQUIRREL{reg_sign}-III scabblers, and VAC-PAC. The scabblers are designed to scarify concrete floors and slabs using cross section, tungsten carbide tipped bits. The bits are designed to remove concrete in 3/8 inch increments. The bits are either 9-tooth or demolition type. The scabblers are used with a vacuum system designed to collect and filter the concrete dust and contamination that is removed from the surface. The safety and health evaluation during the human factors assessment focused on two main areas: noise and dust.

  4. Calculating Masses, Densities, And Compositions Of Alloys

    NASA Technical Reports Server (NTRS)

    De Groh, H.

    1990-01-01

    Metallurgical Programs include three simple programs calculating solutions to problems common to metallurgical engineers and persons making metal castings. First program calculates mass of binary ideal mixture (alloy). Second, calculates densities of binary ideal mixture. Third, converts atomic percentages of binary mixture to weight percentages. Uses simple equations to assist with routine calculations. Written in Microsoft QuickBASIC.

  5. SU-E-T-90: Concrete Forward-Scatter Fractions for Radiotherapy Shielding Applications

    SciTech Connect

    Tanny, S; Parsai, E

    2014-06-01

    Purpose: There is little instruction within the primary shielding guidance document NCRP 151 for vault designs where the primary beam intercepts the maze. We have conducted a Monte-Carlo study to characterize forward-scattered radiation from concrete barriers with the intent of quantifying what amount of additional shielding outside the primary beam is needed in this situation. Methods: We reproduced our vault in MCNP 5 and simulated spectra obtained from the literature and from our treatment planning system for 10 and 18 MV beams. Neutron and gamma-capture contributions were not simulated. Energy deposited was scored at isocenter in a water phantom, within various cells that comprised the maze, and within cells that comprised the vault door. Tracks were flagged that scattered from within the maze to the door and their contributions were tallied separately. Three different concrete mixtures found in the literature were simulated. An empirically derived analytic equation was used for comparison, utilizing patient scatter fractions to approximate the scatter from concrete. Results: Our simulated data confirms that maze-scattered radiation is a significant contribution to total photon dose at the door. It contributes between 20-35% of the photon shielding workload. Forward-scatter fractions for concrete were somewhat dependent on concrete composition and the relative abundance of higher-Z elements. Scatter fractions were relatively insensitive to changes in the primary photon spectrum. Analytic results were of the same magnitude as simulated results. Conclusions: Forward-scattered radiation from the maze barrier needs to be included in the photon workload for shielding calculations in non-standard vault designs. Scatter fractions will vary with concrete composition, but should be insensitive to spectral changes between machine manufacturers. Further plans for investigation include refined scatter fractions for various concrete compositions, scatter fraction

  6. High temperature polymer concrete compositions

    DOEpatents

    Fontana, Jack J.; Reams, Walter

    1985-01-01

    This invention is concerned with a polymer concrete composition, which is a two-component composition useful with many bases including metal. Component A, the aggregate composition, is broadly composed of silica, silica flour, portland cement, and acrylamide, whereas Component B, which is primarily vinyl and acrylyl reactive monomers, is a liquid system. A preferred formulation emphasizing the major necessary components is as follows: ______________________________________ Component A: Silica sand 60-77 wt. % Silica flour 5-10 wt. % Portland cement 15-25 wt. % Acrylamide 1-5 wt. % Component B: Styrene 50-60 wt. % Trimethylolpropane 35-40 wt. % trimethacrylate ______________________________________ and necessary initiators, accelerators, and surfactants.

  7. 36. VAL, DETAIL OF TYPICAL INTERIOR OF CONCRETE 'A' FRAME ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    36. VAL, DETAIL OF TYPICAL INTERIOR OF CONCRETE 'A' FRAME STRUCTURE SHOWING PAINTED CONCRETE WALLS, CONCRETE STAIRS AND INTERIOR WOOD DOOR. - Variable Angle Launcher Complex, Variable Angle Launcher, CA State Highway 39 at Morris Reservior, Azusa, Los Angeles County, CA

  8. Evaluating Whole Chemical Mixtures and Sufficient Similarity

    EPA Science Inventory

    This powerpoint presentation supports apresentation describing dose-response assessment for complex chemical mixtures including deriving reference doses for mixtures evaluating sufficient similarity among chemical mixtures.

  9. An approach based on ultrahigh performance liquid chromatography-atmospheric pressure chemical ionization-mass spectrometry allowing the quantification of both individual phytosteryl and phytostanyl fatty acid esters in complex mixtures.

    PubMed

    Scholz, Birgit; Menzel, Nicole; Lander, Vera; Engel, Karl-Heinz

    2016-01-15

    A method for the analysis of both individual phytosteryl and phytostanyl fatty acid esters in complex mixtures was established. The approach was based on a previously not described combination of three elements: (i) the formation of [M-FA+H](+) fragment ions via APCI (atmospheric pressure chemical ionization), (ii) a highly efficient UHPLC-based separation on a 1.7 μ C8 column, previously established for phytostanyl fatty acid esters, allowing the distinction of individual fatty acid esters sharing the same sterol/stanol nucleus and of isotope peaks of phytosteryl fatty acid esters and corresponding phytostanyl fatty acid esters based on these [M-FA+H](+) fragment ions, and (iii) the adjustment of the APCI conditions allowing the differential APCI-MS-SIM (single ion monitoring) detection of phytostanyl esters of linoleic and linolenic acid based on their distinct formation of a [M+H](+) ion. The usefulness of the methodology was demonstrated by the analysis of a commercially available enriched margarine. Two runs per sample allowed the quantification of 35 target analytes; the total amounts of esters were between 124.7 and 125.3g/kg, being in good agreement with the labelled 125 g/kg. Validation data were elaborated for 35 individual fatty acid esters of sitosterol, campesterol, brassicasterol, stigmasterol, sitostanol and campestanol. Recovery rates ranged from 95 to 106%; the coefficients of variation were consistently <5%, except for stigmasteryl-18:1. The approach describes for the first time a quantification of both individual phytosteryl and phytostanyl fatty acid esters and thus closes an analytical gap related to this class of health-relevant food constituents.

  10. A Gross Way to Teach Relative Mass.

    ERIC Educational Resources Information Center

    Horsch, Elizabeth; Burnett, Diane

    1995-01-01

    Describes an activity designed to give students practice in generating, analyzing, and interpreting class data to create a concrete representation of relative mass and atomic mass unit. The activity uses rice, corn, and beans and employs a historical approach to engage students. (DDR)

  11. Testing of plain and fibrous concrete single cavity prestressed concrete reactor vessel models

    SciTech Connect

    Oland, C.B.

    1985-01-01

    Two single-cavity prestressed concrete reactor vessel (PCRV) models were fabricated and tested to failure to demonstrate the structural response and ultimate pressure capacity of models cast from high-strength concretes. Concretes with design compressive strengths in excess of 70 MPa (10,000 psi) were developed for this investigation. One model was cast from plain concrete and failed in shear at the head region. The second model was cast from fiber reinforced concrete and failed by rupturing the circumferential prestressing at the sidewall of the structure. The tests also demonstrated the capabilities of the liner system to maintain a leak-tight pressure boundary. 3 refs., 4 figs.

  12. Evaluation Of Liner Back-pressure Due To Concrete Pore Pressure At Elevated Temperatures

    SciTech Connect

    James, R.J.; Rashid, Y.R.; Liu, A.S.; Gou, B.

    2006-07-01

    wall considering the time-dependent temperature distribution that evolves following the LOCA. The pressure distribution at each time increment is balanced for mass diffusion using Darcy's Law for mass flux under a pressure gradient. The total mass for the free water, the water vapor, and the non-condensable gases in the pore volumes is tracked to maintain conservation of mass. The evolution of liner back-pressure with time is then based on detailed finite element modeling that incorporates the pore pressure model into a concrete cracking analysis with full coupling between the temperatures, pressures, and liner displacements. (authors)

  13. Assessing the performance of novel software Strain Solution on automated discrimination of Escherichia coli serotypes and their mixtures using matrix-assisted laser desorption ionization-time of flight mass spectrometry.

    PubMed

    Ojima-Kato, Teruyo; Yamamoto, Naomi; Iijima, Yoshio; Tamura, Hiroto

    2015-12-01

    O157, O26, and O111 are the most important O serogroups of enterohemorrhagic Escherichia coli worldwide. Recently we reported a strategy for discriminating these serotypes from the others using matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) based on the S10-spc-alpha operon gene-encoded ribosomal protein mass spectrum (S10-GERMS) method. To realize the fully automated identification of microorganisms at species- or serotype-level with the concept of S10-GERMS method, novel software named Strain Solution for MALDI-TOF MS was developed. In this study, the Strain Solution was evaluated with a total of 45 E. coli isolates including O26, O91, O103, O111, O115, O121, O128, O145, O157, O159, and untyped serotypes. The Strain Solution could accurately discriminate 92% (11/12) of O157 strains, 100% (13/13) of O26 and O111 strains from the others with three biomarkers in an automated manner. In addition, this software could identify 2 different E. coli strains (K-12 as a non-O157 representative and O157) in mixed samples. The results suggest that Strain Solution will be useful for species- or serotype-level classification of microorganisms in the fields of food safety and diagnostics.

  14. Radionuclide Retention in Concrete Wasteforms

    SciTech Connect

    Wellman, Dawn M.; Jansik, Danielle P.; Golovich, Elizabeth C.; Cordova, Elsa A.

    2012-09-24

    Assessing long-term performance of Category 3 waste cement grouts for radionuclide encasement requires knowledge of the radionuclide-cement interactions and mechanisms of retention (i.e., sorption or precipitation); the mechanism of contaminant release; the significance of contaminant release pathways; how wasteform performance is affected by the full range of environmental conditions within the disposal facility; the process of wasteform aging under conditions that are representative of processes occurring in response to changing environmental conditions within the disposal facility; the effect of wasteform aging on chemical, physical, and radiological properties; and the associated impact on contaminant release. This knowledge will enable accurate prediction of radionuclide fate when the wasteforms come in contact with groundwater. Data collected throughout the course of this work will be used to quantify the efficacy of concrete wasteforms, similar to those used in the disposal of LLW and MLLW, for the immobilization of key radionuclides (i.e., uranium, technetium, and iodine). Data collected will also be used to quantify the physical and chemical properties of the concrete affecting radionuclide retention.

  15. RADON GENERATION AND TRANSPORT THROUGH CONCRETE FOUNDATIONS

    EPA Science Inventory

    The report gives results of an examination of radon generation and transport through Florida residential concretes for their contribution to indoor radon concentrations. Radium concentrations in the 11 concretes tested were all <2.5 pCi/g and radon emanation coefficients were all...

  16. Construction Cluster Volume IV: [Concrete Work].

    ERIC Educational Resources Information Center

    Pennsylvania State Dept. of Justice, Harrisburg. Bureau of Correction.

    The document is the fourth of a series, to be integrated with a G.E.D. program, containing instructional materials for the construction cluster. The volume focuses on concrete work and consists of 20 instructional units which require a month of study. The units include: (1) uses of concrete and occupational information; (2) soils, drainage, and…

  17. "Concreteness Fading" Promotes Transfer of Mathematical Knowledge

    ERIC Educational Resources Information Center

    McNeil, Nicole M.; Fyfe, Emily R.

    2012-01-01

    Recent studies have suggested that educators should avoid concrete instantiations when the goal is to promote transfer. However, concrete instantiations may benefit transfer in the long run, particularly if they are "faded" into more abstract instantiations. Undergraduates were randomly assigned to learn a mathematical concept in one of three…

  18. Assessing the Concreteness of Relational Representation

    ERIC Educational Resources Information Center

    Rein, Jonathan R.; Markman, Arthur B.

    2010-01-01

    Research has shown that people's ability to transfer abstract relational knowledge across situations can be heavily influenced by the concrete objects that fill relational roles. This article provides evidence that the concreteness of the relations themselves also affects performance. In 3 experiments, participants viewed simple relational…

  19. Properties and uses of concrete, appendix B

    NASA Technical Reports Server (NTRS)

    Corley, Gene

    1992-01-01

    Concretes that can now be formed have properties which may make them valuable for lunar or space construction. These properties include high compressive strength, good flexural strength (when reinforced), and favorable responses to temperature extremes (even increased strength at low temperatures). These and other properties of concrete are discussed.

  20. A Study on the Cover Failure in Concrete Structure Following Concrete Deterioration

    SciTech Connect

    Choo, Y.H.; Lee, Y.H.; Lee, C.M.; Lee, K.J.

    2008-07-01

    The RC (Reinforced Concrete) structures in the spent fuel dry storage is required structural integrity for a long period of the service life time. A study on the concrete cracking behavior by stress on concrete is necessary for life time estimation of structures because concrete cracking can reduce the radiation shielding performance and deteriorate the durability of spent fuel dry storage. The purpose of this study is to analyze the relationship between the range of the steel expansion and the crack creation and propagation using the ABAQUS tool. Parameters used in this study were concrete strength, concrete cover depth and the steel diameter. The value of steel radius to volume expansion was applied to suppose the expansion of reinforcing bar under the load condition. As a result of this case study, it is confirmed that the critical steel expansion which can initiate cracking is proportional to tensile strength. And primary factors which effect crack creation of concrete cover are in order of concrete strength, cover thickness and steel diameter. If concrete strength is lowered about its 30%, the rate of surface crack occurrence accelerates 15 times maximally. The critical expansion value of steel increased as the increment of concrete cover depth. The surface cracking of concrete cover was created at the value of steel expansion, ranging from 0.019 to 0.051 mm under the cover depth 50 mm. (authors)

  1. Concreteness effects revisited: the influence of dynamic visual noise on memory for concrete and abstract words.

    PubMed

    Parker, Andrew; Dagnall, Neil

    2009-05-01

    Two experiments are presented that investigate the effects of dynamic visual noise (DVN) on memory for concrete and abstract words. Memory for concrete words is typically superior to that of abstract words and is referred to as the concreteness effect. DVN is a procedure that has been demonstrated to interfere selectively with visual working memory and the generation of images from long-term memory. It was reasoned that if concreteness effects arise because of the ability of the latter to activate visual representations, then DVN should selectively impair memory for concrete words. Experiment 1 found DVN to selectively reduce free recall of concrete words. Experiment 2 investigated recognition memory and found DVN to reduce memory accuracy and remember responses, while increasing know responses to concrete words.

  2. Importance of Molecular Structure on the Thermophoresis of Binary Mixtures.

    PubMed

    Kumar, Pardeep; Goswami, Debabrata

    2014-12-26

    Using thermal lens spectroscopy, we study the role of molecular structural isomers of butanol on the thermophoresis (or Soret effect) of binary mixtures of methanol in butanol. In this study, we show that the thermal lens signal due to the Soret effect changes its sign for all the different concentrations of binary mixtures of butanol with methanol except for the one containing tertiary-butanol. The magnitude and sign of the Soret coefficients strongly depend on the molecular structure of the isomers of butanol in the binary mixture with methanol. This isomerization dependence is in stark contrast to the expected mass dependence of the Soret effect.

  3. Toxicological approaches to complex mixtures.

    PubMed Central

    Mauderly, J L

    1993-01-01

    This paper reviews the role of toxicological studies in understanding the health effects of environmental exposures to mixtures. The approach taken is to review mixtures that have received the greatest emphasis from toxicology; major mixtures research programs; the toxicologist's view of mixtures and approaches to their study; and the complementary roles of toxicological, clinical, and epidemiological studies. Studies of tobacco smoke, engine exhaust, combustion products, and air pollutants comprise most of the past research on mixtures. Because of their great experimental control over subjects, exposures, and endpoints, toxicologists tend to consider a wider range of toxic interactions among mixture components and sequential exposures than is practical for human studies. The three fundamental experimental approaches used by toxicologists are integrative (studying the mixture as a whole), dissective (dissecting a mixture to determine causative constituents), and synthetic (studying interactions between agents in simple combinations). Toxicology provides information on potential hazards, mechanisms by which mixture constituents interact to cause effects, and exposure dose-effect relationships; but extrapolation from laboratory data to quantitative human health risks is problematic. Toxicological, clinical, and epidemiological approaches are complementary but are seldom coordinated. Fostering synergistic interactions among the disciplines in studying the risks from mixtures could be advantageous. PMID:7515806

  4. Toxicological approaches to complex mixtures.

    PubMed

    Mauderly, J L

    1993-12-01

    This paper reviews the role of toxicological studies in understanding the health effects of environmental exposures to mixtures. The approach taken is to review mixtures that have received the greatest emphasis from toxicology; major mixtures research programs; the toxicologist's view of mixtures and approaches to their study; and the complementary roles of toxicological, clinical, and epidemiological studies. Studies of tobacco smoke, engine exhaust, combustion products, and air pollutants comprise most of the past research on mixtures. Because of their great experimental control over subjects, exposures, and endpoints, toxicologists tend to consider a wider range of toxic interactions among mixture components and sequential exposures than is practical for human studies. The three fundamental experimental approaches used by toxicologists are integrative (studying the mixture as a whole), dissective (dissecting a mixture to determine causative constituents), and synthetic (studying interactions between agents in simple combinations). Toxicology provides information on potential hazards, mechanisms by which mixture constituents interact to cause effects, and exposure dose-effect relationships; but extrapolation from laboratory data to quantitative human health risks is problematic. Toxicological, clinical, and epidemiological approaches are complementary but are seldom coordinated. Fostering synergistic interactions among the disciplines in studying the risks from mixtures could be advantageous.

  5. Metakaolin as a radon retardant from concrete.

    PubMed

    Lau, B M F; Balendran, R V; Yu, K N

    2003-01-01

    Granite aggregates are known to be the radon source in concrete. Recently, metakaolin has been introduced as a partial substitution of Portland cement to produce high strength concrete. It can effectively reduce the porosity of both the matrix and the aggregate/paste transition zone, which suggests its ability to retard radon emission from concrete aggregates. In the present work, radon exhalation rates from concrete cubes substituted with metakaolin were measured using charcoal canisters and gamma spectroscopy, and were considerably lower than those from normal concrete, by about 30%. The indoor radon concentration reduction is estimated as approximately 9 Bq m(-3) calculated using a room model, causing a 30% reduction in the indoor radon concentration and the corresponding radon dose. Therefore, metakaolin is a simple material to reduce the indoor radon concentration and the radon dose.

  6. Studies on recycled aggregates-based concrete.

    PubMed

    Rakshvir, Major; Barai, Sudhirkumar V

    2006-06-01

    Reduced extraction of raw materials, reduced transportation cost, improved profits, reduced environmental impact and fast-depleting reserves of conventional natural aggregates has necessitated the use of recycling, in order to be able to conserve conventional natural aggregate. In this study various physical and mechanical properties of recycled concrete aggregates were examined. Recycled concrete aggregates are different from natural aggregates and concrete made from them has specific properties. The percentages of recycled concrete aggregates were varied and it was observed that properties such as compressive strength showed a decrease of up to 10% as the percentage of recycled concrete aggregates increased. Water absorption of recycled aggregates was found to be greater than natural aggregates, and this needs to be compensated during mix design.

  7. Recent biogenic phosphorite: Concretions in mollusk kidneys

    USGS Publications Warehouse

    Doyle, L.J.; Blake, N.J.; Woo, C.C.; Yevich, P.

    1978-01-01

    Phosphorite concretions have been detected in the kidneys of two widespread species ofmollusks, Mercenaria mercenaria and Argopecten irradians, which have relatively high population densities. These concretions are thefirst documentation of the direct biogenic formation of phosphorite grains. The concretions are principally amorphous calcium phosphate, which upon being heated yields an x-ray diffraction pattern which is essentially that of chlorapatite. These concretions appear to be a normal formation of the excretory process of mollusks under reproductive, environmental, or pollutant-induced stress. Biogenic production of phosphorite concretions over long periods of time and diagenetic change from amorphous to crystalline structure, coupled with secondary enrichment, may account for the formation of some marine phosphorite desposits which are not easily explained by the chemical precipitation- replacement hypothesis. Copyright ?? 1978 AAAS.

  8. Phosphogypsum slag aggregate-based asphaltic concrete mixes

    SciTech Connect

    Foxworthy, P.T.; Nadimpalli, R.S.; Seals, R.K.

    1996-07-01

    Phosphogypsum is a by-product from the production of phosphoric acid used in the fertilizer and chemical industries. Large production rates and problems associated with its stockpiling have led researchers to seek alternative uses for phosphogypsum, primarily as a construction material. One such use is the extraction of sulfur dioxide for the production of sulfuric acid, a process that also generates a by-product slag aggregate. This study investigated the feasibility of using this slag aggregate in asphaltic concrete binder course mixes. The physical properties of the slag aggregate, such as gradation, specific gravity, absorption, unit weight, and void content, were determined, as well as its durability and environmental characteristics. The Marshall mix design method was used to obtain the optimum asphalt content for this aggregate, while moisture susceptibility was examined using the boiling and modified Lottman tests. Indirect tensile, resilient modulus, and dynamic creep tests were performed on the mix to evaluate its performance potential. The results of the study indicate that phosphogypsum-based slag aggregate can be successfully employed in asphaltic concrete binder course mixtures.

  9. Stabilizer for fuel mixtures

    SciTech Connect

    Abe, M.; Moriyama, N.; Yamamura, M.

    1981-02-24

    A stabilizer for fuel mixtures of finely divided coal and fuel oil is composed of an active ingredient, a non-ionic surface active agent consisting of a block copolymer represented by the following general formula (I): R/sub 1/O-(C/sub 2/H/sup 4/O)l-(C/sub 3/H/sup 6/O)m-(C/sub 2/H/sup 4/O)n-R/sub 2/ (I) wherein r/sub 1/ and r/sub 2/ stand for a hydrogen atom or an alklyl group having 1 to 6 carbon atoms, the mole number (L+n) of added ethylene oxide is in the range of from 30 to 300, the mole number (M) of added propylene oxide is in the range of from 15 to 80, and the content of ethylene oxide in the whole molecule is 40 to 85% by weight.

  10. Concrete spaller. Innovative technology summary report

    SciTech Connect

    1998-12-01

    The US Department of Energy (DOE) has numerous buildings and facilities that have become contaminated through operation of nuclear reactors, fuel fabrication processes, and research laboratory operations. These buildings and facilities, often constructed of concrete, need to be decontaminated before they can be safely decommissioned or demolished. Pacific Northwest National Laboratory`s concrete spaller is a hand-held tool that can be used for decontaminating flat or slightly curved concrete surfaces, obtaining concrete samples, and in-depth removal from cracks in concrete. The concrete spaller includes a 9-ton hydraulic cylinder and spalling bit. It runs from a hydraulic pump that expands the spaller in pre-drilled holes in the concrete. The result is removal of concrete chunks that fall into the attached metal shroud. The concrete spaller is more efficient than traditional tools such as hand-held pneumatic scabblers and scalers. For example, the spaller is capable of spalling 1.3 m{sup 3}/hr (0.23 ft{sup 2}/min), compared to 1.1 m{sup 2}/hr (0.20 ft{sup 2}/min), for the baseline scabbler and scaler demonstrated at 3-mm (1/8-in.) depth. The spaller is also capable of removing concrete at a greater depth than traditional tools. Operating cost of the spaller ($128/m{sup 2} or $11.93/ft{sup 2} [optimum conditions]) is less than the baseline tools: scaler ($155/m{sup 2} or $14.40/ft{sup 2}) and scabbler ($156/m{sup 2} or $14.53/ft{sup 2}).

  11. Radiation Damage In Reactor Cavity Concrete

    SciTech Connect

    Field, Kevin G; Le Pape, Yann; Naus, Dan J; Remec, Igor; Busby, Jeremy T; Rosseel, Thomas M; Wall, Dr. James Joseph

    2015-01-01

    License renewal up to 60 years and the possibility of subsequent license renewal to 80 years has established a renewed focus on long-term aging of nuclear generating stations materials, and recently, on concrete. Large irreplaceable sections of most nuclear generating stations include concrete. The Expanded Materials Degradation Analysis (EMDA), jointly performed by the Department of Energy, the Nuclear Regulatory Commission and Industry, identified the urgent need to develop a consistent knowledge base on irradiation effects in concrete. Much of the historical mechanical performance data of irradiated concrete does not accurately reflect typical radiation conditions in NPPs or conditions out to 60 or 80 years of radiation exposure. To address these potential gaps in the knowledge base, The Electric Power Research Institute and Oak Ridge National Laboratory are working to disposition radiation damage as a degradation mechanism. This paper outlines the research program within this pathway including: (i) defining the upper bound of the neutron and gamma dose levels expected in the biological shield concrete for extended operation (80 years of operation and beyond), (ii) determining the effects of neutron and gamma irradiation as well as extended time at temperature on concrete, (iii) evaluating opportunities to irradiate prototypical concrete under accelerated neutron and gamma dose levels to establish a conservative bound and share data obtained from different flux, temperature, and fluence levels, (iv) evaluating opportunities to harvest and test irradiated concrete from international NPPs, (v) developing cooperative test programs to improve confidence in the results from the various concretes and research reactors, (vi) furthering the understanding of the effects of radiation on concrete (see companion paper) and (vii) establishing an international collaborative research and information exchange effort to leverage capabilities and knowledge.

  12. Mixture segregation by an inertial cavitation bubble.

    PubMed

    Grossier, R; Louisnard, O; Vargas, Y

    2007-04-01

    Pressure diffusion is a mass diffusion process forced by pressure gradients. It has the ability to segregate two species of a mixture, driving the densest species toward high pressure zones, but requires very large pressure gradients to become noticeable. An inertial cavitation bubble develops large pressure gradients in its vicinity, especially as the bubble rebounds at the end of its collapse, and it is therefore expected that a liquid mixture surrounding such a bubble would become segregated. Theory developed in an earlier paper shows that this is indeed the case for sufficiently large molecules or nano-particles. The main theoretical results are recalled and a possible implication of this segregation phenomenon on the well-known cavitation-enhanced crystals nucleation is proposed.

  13. Numerical simulation of hydro-thermo-mechanical behavior of concrete structures exposed to elevated temperatures

    NASA Astrophysics Data System (ADS)

    Chung, Jae Hyeon

    In this study, thermal spalling of high-strength concrete structural elements has been investigated by developing numerical models capable of analyzing the combined effects of mass and heat transfer phenomena on thermally induced stresses. Through the use of finite difference simulations, this study investigates moisture effects on thermodynamic states of concrete at elevated temperatures and the influence of pore pressure on development of thermal stress induced by temperature gradients. A finite element stress analysis model is combined with finite difference simulations to predict stress states capable of inducing spalling of the type that has been observed both in the field and in laboratory fire testing of concrete structural elements. The combined hydro-thermo-mechanical analysis procedure presented here may eventually serve as a critical component of stress analysis used for evaluating the fire resistance of high-strength concrete structural systems. The model of concrete exposed to fire that is developed herein involves mass and heat transport phenomena in a multi-phase continuum. Simultaneous flow of multiple fluid phases (i.e., liquid and gaseous) is modeled using newly proposed constitutive relationships that are considered more accurate than those previously available in terms of assessment of thermodynamic state variables of concrete system. In addition, numerical simulations are used to explore the effects that steel reinforcing bars have on internal temperature and pressure within concrete members. Pore pressure and temperature time histories from hydro-thermal finite difference simulations are presented and discussed. Results from the simulations yield an improved understanding of the thermodynamic state variables such as pore pressure, temperature, and degree of liquid water saturation. Selection of constitutive models to describe the flow characteristics of concrete and the procedures implemented for the creation of the concrete models are also

  14. Lunar cement and lunar concrete

    NASA Technical Reports Server (NTRS)

    Lin, T. D.

    1991-01-01

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

  15. SA-based concrete seismic stress monitoring: a case study for normal strength concrete

    NASA Astrophysics Data System (ADS)

    Hou, S.; Zhang, H. B.; Ou, J. P.

    2016-09-01

    The stress history of concrete structures that have survived an earthquake can serve as a critical index to evaluate the health of the structure. There are currently few reliable monitoring methods to assess concrete stress after a seismic event. Piezoelectric-based smart aggregate (SA) provides an innovative experimental approach to monitor stress on concrete. The principle of SA-based concrete seismic stress monitoring is based on the assumption that concrete stress can be reliably predicted by the average output voltages of limited SAs with an acceptable margin of error. In this study, the meso-scale randomness of concrete was evaluated throughout the overall stress range of concrete and the influence of different load paths was considered. Four cylindrical specimens of normal strength concrete were embedded with a total of 24 SAs. The SA output sensitivity curve in the paths of loading-unloading with different amplitudes and monotonic loading up to failure was obtained. Monitoring errors were analyzed during pre- and post-peak stages from the experimental results. This research suggests that SA-based concrete seismic stress monitoring for normal strength concrete is reliable.

  16. SA-based concrete seismic stress monitoring: a case study for normal strength concrete

    NASA Astrophysics Data System (ADS)

    Hou, S.; Zhang, H. B.; Ou, J. P.

    2016-09-01

    The stress history of concrete structures that have survived an earthquake can serve as a critical index to evaluate the health of the structure. There are currently few reliable monitoring methods to assess concrete stress after a seismic event. Piezoelectric-based smart aggregate (SA) provides an innovative experimental approach to monitor stress on concrete. The principle of SA-based concrete seismic stress monitoring is based on the assumption that concrete stress can be reliably predicted by the average output voltages of limited SAs with an acceptable margin of error. In this study, the meso-scale randomness of concrete was evaluated throughout the overall stress range of concrete and the influence of different load paths was considered. Four cylindrical specimens of normal strength concrete were embedded with a total of 24 SAs. The SA output sensitivity curve in the paths of loading–unloading with different amplitudes and monotonic loading up to failure was obtained. Monitoring errors were analyzed during pre- and post-peak stages from the experimental results. This research suggests that SA-based concrete seismic stress monitoring for normal strength concrete is reliable.

  17. TESTING AND ANALYSIS OF CAP CONCRETE STRESS AND STRAIN DUE TO SHRINKAGE, CREEP, AND EXPANSION FINAL REPORT

    SciTech Connect

    Guerrero, H.; Restivo, M.

    2011-08-01

    In-situ decommissioning of Reactors P- and R- at the Savannah River Site will require filling the reactor vessels with a special concrete based on materials such as magnesium phosphate, calcium aluminate or silica fume. Then the reactor vessels will be overlain with an 8 ft. thick layer of Ordinary Portland Cement (OPC) steel reinforced concrete, called the 'Cap Concrete'. The integrity of this protective layer must be assured to last for a sufficiently long period of time to avoid ingress of water into the reactor vessel and possible movement of radioactive contamination into the environment. During drying of this Cap Concrete however, shrinkage strains are set up in the concrete as a result of diffusion and evaporation of water from the top surface. This shrinkage varies with depth in the poured slab due to a non-uniform moisture distribution. This differential shrinkage results in restraint of the upper layers with larger shrinkage by lower layers with lesser displacements. Tensile stresses can develop at the surface from the strain gradients in the bulk slab, which can lead to surface cracking. Further, a mechanism called creep occurs during the curing period or early age produces strains under the action of restraining forces. To investigate the potential for surface cracking, an experimental and analytical program was started under TTQAP SRNL-RP-2009-01184. Slab sections made of Cap Concrete mixture were instrumented with embedded strain gages and relative humidity sensors and tested under controlled environmental conditions of 23 C and relative humidities (RH) of 40% and 80% over a period of 50 days. Calculation methods were also developed for predictions of stress development in the full-scale concrete placement over the reactor vessels. These methods were evaluated by simulating conditions for the test specimens and the calculation results compared to the experimental data. A closely similar test with strain gages was performed by Kim and Lee for a

  18. Self-cleaning geopolymer concrete - A review

    NASA Astrophysics Data System (ADS)

    Norsaffirah Zailan, Siti; Mahmed, Norsuria; Bakri Abdullah, Mohd Mustafa Al; Sandu, Andrei Victor

    2016-06-01

    Concrete is the most widely used construction materials for building technology. However, cement production releases high amounts of carbon dioxide (CO2) to the atmosphere that leads to increasing the global warming. Thus, an alternative, environmental friendly construction material such as geopolymer concrete has been developed. Geopolymer concrete applies greener alternative binder, which is an innovative construction material that replaces the Portland cement. This technology introduced nano-particles such as nanoclay into the cement paste in order to improve their mechanical properties. The concrete materials also have been developed to be functioned as self-cleaning construction materials. The self-cleaning properties of the concrete are induced by introducing the photocatalytic materials such as titania (TiO2) and zinc oxide (ZnO). Self-cleaning concrete that contains those photocatalysts will be energized by ultraviolet (UV) radiation and accelerates the decomposition of organic particulates. Thus, the cleanliness of the building surfaces can be maintained and the air surrounding air pollution can be reduced. This paper briefly reviews about self-cleaning concrete.

  19. Microbially influenced degradation of concrete structures

    NASA Astrophysics Data System (ADS)

    Rogers, Robert D.; Hamilton, Melinda A.; Nelson, Lee O.

    1998-03-01

    Steel reinforced concrete is the most widely used construction material in the world. The economic costs of repair or replacement of environmentally damaged concrete structures is astronomical. For example, half of the concrete bridges in the Federal Department of Transportation highway system are in need of major repairs. Microbially influenced degradation of concrete (MID) is one of the recognized degradative processes known to adversely affect concrete integrity. It is not possible to assign a specific percent of effect to any of these processes. However, MID has been shown to be as aggressive as any of the physical/chemical phenomena. In addition, the possibility exists that there is a synergism which results in cumulative effects from all the processes. Three groups of bacteria are known to promote MID. Of these, sulfur-oxidizing bacteria (SOB) are the most aggressive. Much is known about the nutritional needs of these bacteria. However, there has not been a biological linkage established between the presence of environmental, polluting sulfur sources and the degradation of concrete structures. It has been shown that the environmental pollutants sulfur dioxide and sulfite can be utilized by active SOB for the biological production of sulfuric acid. Therefore, it is not a reach of reality to assume that SOB exposed to these pollutants could have a major impact on the degradation of concrete structures. But, until the environment sulfur loop is closed it will not be possible to calculate how important SOB activity is in initiating and promoting damage.

  20. Modeling the electrokinetic decontamination of concrete

    SciTech Connect

    Harris, M.T.; DePaoli, D.W.; Ally, M.R.

    1997-01-01

    The decontamination of concrete is a major concern in many Department of (DOE) facilities. Numerous techniques (abrasive methods, manual methods, ultrasonics, concrete surface layer removal, chemical extraction methods, etc.) have been used to remove radioactive contamination from the surface of concrete. Recently, processes that are based on electrokinetic phenomena have been developed to decontaminate concrete. Electrokinetic decontamination has been shown to remove from 70 to over 90% of the surface radioactivity. To evaluate and improve the electrokinetic processes, a model has been developed to simulate the transport of ionic radionuclei constituents through the pores of concrete and into the anolyte and catholyte. The model takes into account the adsorption and desorption kinetics of the radionuclei from the pore walls, and ion transport by electro-osmosis, electromigration, and diffusion. A numerical technique, orthogonal collocation, is used to simultaneously solve the governing convective diffusion equations for a porous concrete slab and the current density equation. This paper presents the theoretical framework of the model and the results from the computation of the dynamics of ion transport during electrokinetic treatment of concrete. The simulation results are in good agreement with experimental data.

  1. Nondestructive evaluation of thick concrete structures

    NASA Astrophysics Data System (ADS)

    Clayton, Dwight A.

    2015-03-01

    Concrete has been used in the construction of nuclear power plants (NPPs) due to three primary properties: its low cost, structural strength, and ability to shield radiation. Examples of concrete structures important to the safety of Light Water Reactor (LWR) plants include the containment building, spent fuel pool, and cooling towers. Use in these structures has made concrete's long-term performance crucial for the safe operation of commercial NPPs. Extending LWR operating period to 60 years and beyond will likely increase susceptibility and severity of known forms of degradation. New mechanisms of materials degradation are also possible. This creates the need to be able to nondestructively evaluate the current subsurface concrete condition of aging concrete material in NPP structures. The size and complexity of NPP containment structures and heterogeneity of Portland cement concrete make characterization of the degradation extent a difficult task. Specially designed and fabricated test specimens can provide realistic flaws that are similar to actual flaws in terms of how they interact with a particular nondestructive evaluation (NDE) technique. Artificial test blocks allow the isolation of certain testing problems as well as the variation of certain parameters. Representative large heavily reinforced concrete specimens would allow for comparative testing to evaluate the state-of-the-art NDE in this area and to identify additional developments necessary to address the challenges potentially found in NPPs.

  2. Capillary column gas chromatography, resonance enhanced multiphoton ionization, time-of-flight mass spectrometry laser-induced fluorescence, flame ionization detection system for the determination of polynuclear aromatic compounds in complex mixtures

    SciTech Connect

    Dobson, R.L.M.

    1986-06-01

    Of the thousands of chemical compounds that have been deemed mutagenic or carcinogenic, it is generally agreed that the polynuclear aromatic hydrocarbons (PAC) are among the most potent. Because of the wide range of potency of PAC, even among geometric isomers and substitutional derivatives, it is important to fully characterize these samples. This task is a formidable one, usually requiring elaborate sample clean-up and fractionation prior to analysis. A multidimensional, laser-based analytical instrument has been developed that, when utilized to the full extent of its capabilities, could be the solution to this complex analytical problem. The overall technique is termed Capillary Column Gas Chromatography, Resonance Enhanced Multiphoton Ionization, Time-Of-Flight Mass Spectrometry, Laser-induced Fluorescence, with parallel Flame Ionization Detection (CC/GC-REMPI-TOF/MS-LIF-FID). This system combines the selectivity and sensitivity of two complementary laser-based methods, REMPI and LIF, with an extremely powerful and proven analytical tool, GC/MS. The GC effluent passes through the ion source of a TOF/MS, where it is interrogated by a tunable ultraviolet laser beam. All laser-analyte interaction products (cations, electrons, and photons) are simultaneously monitored utilizing the TOF/MS, a total electron current detector (TECD), and a LIF detector. The simultaneous availability of this information simplifies the characterization task. The present absolute detection limits for several PAC have been determined to be in the low picogram range. Also, a linear dynamic range of approximately four orders of magnitude has been established for the TECD, indicating that this technique is both sensitive and quantitative. Further, the use of deuterated analogs, of selected PAC, as internal reference standards greatly assists in quantitation. 219 refs., 37 figs., 13 tabs.

  3. Capillary column gas chromatography, resonance enhanced multiphoton ionization, time-of-flight mass spectrometry, laser-induced fluorescence, flame ionization detection system for the determination of polynuclear aromatic compounds in complex mixtures

    SciTech Connect

    Dobson, R.L.M.

    1986-01-01

    A method is reached to fully characterize the polynuclear aromatic hydrocarbons (PAC) that have been deemed to be highly mutagenic or carcinogenic. A multidimensional, laser-based analytical instrument has been developed that, when utilized to the full extent of its capabilities could be the solution to this complex analytical problem. The overall technique is termed Capillary Column Gas Chromatography, Resonance Enhanced Multiphoton Ionization, Time-of-Flight Mass Spectrometry, Laser-induced Fluorescence, with parallel Flame Ionization Detection (CC/GC-REMPI-TOF/MS-LIF-FID). This system combines the selectivity of two complementary laser-based methods, REMPI and LIF, with an extremely powerful and proven analytical tool, GC/MS. The GC effluent passes through the ion source of a TOF/MS, where it is interrogated by a tunable ultraviolet laser beam. Thus, PAC and other absorbing species may be selectively excited and/or ionized in the presence of nonabsorbing components. All laser-analyte interaction products (actions, electrons, and photons) are simultaneously monitored utilizing the TOF/MS, a total electron current detector (TECD), and a LIF detector. The main advantage of this technique is that all analytically useful data for each absorbing chromatographic eluent may be collected on-the-fly. The simultaneous availability of this information simplifies the characterization task. The present absolute detection limits for several PAC have been determined to be low picogram range. Also, a linear dynamic range of approximately four orders of magnitude has been established for the TECD, indicating that this technique is both sensitive and quantitative. Further, the use of deuterated analogs, of selected PAC, as internal reference standards greatly assists in quantitation.

  4. Mixture design and multivariate analysis in mixture research.

    PubMed Central

    Eide, I; Johnsen, H G

    1998-01-01

    Mixture design has been used to identify possible interactions between mutagens in a mixture. In this paper the use of mixture design in multidimensional isobolographic studies is introduced. Mutagenicity of individual nitro-polycyclic aromatic hydrocarbons (PAH) was evaluated is an organic extract of diesel exhaust particles (DEPs). The particles were extracted with dichloromethane (DCM). After replacing DCM with dimethyl sulfoxide, the extract was spiked with three individual nitro-PAH: 1-nitropyrene, 2-nitrofluorene, and 1,8-dinitropyrene. The nitro-PAH were added separately and in various combinations to the extract to determine the effects of each variable and to identify possible interactions between the individual nitro-PAH and between the nitro-PAH and the extract. The composition of the mixtures was determined by mixture design (linear axial normal) with four variables (the DEP extract and the three nitro-PAH, giving 8 different mixtures plus a triplicate centerpoint, i.e., a total of 11. The design supports a model with linear and interaction (product) terms. Two different approaches were used: traditional mixture design within a well-defined range on the linear part of the dose-response curves and an isobolographic mixture design with equipotent doses of each variable. The mixtures were tested for mutagenicity in the Ames assay using the TA98 strain of Salmonella typhimurium. The data were analyzed with projections to latent structures (PLS). The three individual nitro-PAH and the DEP extract acted additively in the Ames test. The use of mixture design either within a well-defined range of the linear part on the dose-response curve or with equipotent doses saves experiments and reduces the possibility of false interaction terms in situations with dose additivity or response additivity. Images Figure 1 Figure 2 PMID:9860895

  5. Mixture design and multivariate analysis in mixture research.

    PubMed

    Eide, I; Johnsen, H G

    1998-12-01

    Mixture design has been used to identify possible interactions between mutagens in a mixture. In this paper the use of mixture design in multidimensional isobolographic studies is introduced. Mutagenicity of individual nitro-polycyclic aromatic hydrocarbons (PAH) was evaluated is an organic extract of diesel exhaust particles (DEPs). The particles were extracted with dichloromethane (DCM). After replacing DCM with dimethyl sulfoxide, the extract was spiked with three individual nitro-PAH: 1-nitropyrene, 2-nitrofluorene, and 1,8-dinitropyrene. The nitro-PAH were added separately and in various combinations to the extract to determine the effects of each variable and to identify possible interactions between the individual nitro-PAH and between the nitro-PAH and the extract. The composition of the mixtures was determined by mixture design (linear axial normal) with four variables (the DEP extract and the three nitro-PAH, giving 8 different mixtures plus a triplicate centerpoint, i.e., a total of 11. The design supports a model with linear and interaction (product) terms. Two different approaches were used: traditional mixture design within a well-defined range on the linear part of the dose-response curves and an isobolographic mixture design with equipotent doses of each variable. The mixtures were tested for mutagenicity in the Ames assay using the TA98 strain of Salmonella typhimurium. The data were analyzed with projections to latent structures (PLS). The three individual nitro-PAH and the DEP extract acted additively in the Ames test. The use of mixture design either within a well-defined range of the linear part on the dose-response curve or with equipotent doses saves experiments and reduces the possibility of false interaction terms in situations with dose additivity or response additivity. PMID:9860895

  6. Decomposition of diverse litter mixtures in streams.

    PubMed

    Lecerf, Antoine; Risnoveanu, Geta; Popescu, Cristina; Gessner, Mark O; Chauvet, Eric

    2007-01-01

    In view of growing interest in understanding how biodiversity affects ecosystem functioning, we investigated effects of riparian plant diversity on litter decomposition in forest streams. Leaf litter from 10 deciduous tree species was collected during natural leaf fall at two locations (Massif Central in France and Carpathians in Romania) and exposed in the field in litter bags. There were 35 species combinations, with species richness ranging 1-10. Nonadditive effects on the decomposition of mixed-species litter were minor, although a small synergistic effect was observed in the Massif Central stream where observed litter mass remaining was significantly lower overall than expected from data on single-species litter. In addition, variability in litter mass remaining decreased with litter diversity at both locations. Mean nitrogen concentration of single- and mixed-species litters (0.68-4.47% of litter ash-free dry mass) accounted for a large part of the variation in litter mass loss across species combinations. For a given species or mixture, litter mass loss was also consistently faster in the Massif Central than in the Carpathians, and the similarity in general stream characteristics, other than temperature, suggests that this effect was largely due to differences in thermal regimes. These results support the notion that decomposition of litter mixtures is primarily driven by litter quality and environmental factors, rather than by species richness per se. However, the observed consistent decrease in variability of decomposition rate with increasing plant species richness indicates that conservation of riparian tree diversity is important even when decomposition rates are not greatly influenced by litter mixing.

  7. Investigation of electrokinetic decontamination of concrete

    SciTech Connect

    DePaoli, D.W.; Harris, M.T.; Morgan, I.L.; Ally, M.R.

    1995-12-31

    Experiments have been conducted to investigate the capabilities of electrokinetic decontamination of concrete. Batch equilibration studies have determined that the loading of cesium and strontium on concrete may be decreased using electrolyte solutions containing competing cations, while solubilization of uranium and cobalt, that precipitate at high pH, will require lixiviants containing complexing agents. Dynamic electrokinetic experiments showed greater mobility of cesium than strontium, while some positive results were obtained for the transport of cobalt through concrete using EDTA and for uranium using carbonate.

  8. Greenhouse gas emissions from concrete can be reduced by using mix proportions, geometric aspects, and age as design factors

    NASA Astrophysics Data System (ADS)

    Miller, Sabbie A.; Horvath, Arpad; Monteiro, Paulo J. M.; Ostertag, Claudia P.

    2015-11-01

    With increased awareness of the emissions of greenhouse gases (GHGs) and the significant contribution from the cement industry, research efforts are being advanced to reduce the impacts associated with concrete production and consumption. A variety of methods have been proposed, one of the most common being the replacement of cement as a binder in concrete with supplementary cementitious materials, such as fly ash (FA), which can have lower environmental effects. The use of FA can change the kinetics of the hydration reactions and, consequently, modify the evolution of the concrete strength over time. Yet the influence of designing structural elements to obtain the required strength at later ages has not been examined in terms of their influence on global warming potential (GWP) of concrete. This research investigates the influence of design age, in addition to mix proportions and geometric aspects, on the GWP associated with making beams, columns, and a concrete building frame. Findings suggest that while the GWP for beams is not highly dependent on concrete mixture strength, the GWP for columns is dependent on strength, thus the influence of required strength at later ages influences GWP of making columns more so than beams. For the concrete frame analyzed, a potential 45% reduction in GWP, depending on mix proportions and design age, was found. Using the findings from this research, the GWP associated with production of concrete in California could be reduced by approximately 1.8 million metric tons of CO2-eq emissions, equivalent to approximately 2% of all industrial GHG emissions in California.

  9. Assessment of high performance concrete containing fly ash and calcium nitrite based corrosion inhibitor as a mean to prevent the corrosion of reinforcing steel

    NASA Astrophysics Data System (ADS)

    Montes-García, P.; Jiménez-Quero, V.; López-Calvo, H.

    2015-01-01

    This research analyses the effectiveness of the water-to-cement ratio (w/c), fly ash and a calcium nitrite based corrosion inhibitor to prevent the corrosion of reinforcing steel embedded in high performance concrete. The interactive effect between the inhibitor and fly ash was evaluated because the occurrence of a negative effect when both ingredients are added together in a concrete mixture has been reported. All the concrete mixtures studied in this investigation had 8.2% of silica fume. Twenty seven prismatic concrete specimens were fabricated with dimensions of 55 × 230 × 300 mm each containing two steel rods embedded for the purpose of corrosion monitoring. The specimens were exposed to a simulated marine environment with two daily cycles of wetting and drying for one year. To evaluate the deterioration of the specimens corrosion potentials and linear polarization resistance tests were carried out. The results indicate that the use of a low w/c, the addition of fly ash and the addition of the corrosion inhibitor contributed to the reduction of the corrosion of steel in the concrete specimens. The results further suggest that the combination of fly ash and corrosion inhibitor does not promote the deterioration of the concrete matrix.

  10. Molecular Survey of Concrete Sewer Biofilm Microbial Communities

    EPA Science Inventory

    Although bacteria are implicated in deteriorating concrete structures, there is very little information on the composition of concrete microbial communities. To this end, we studied different concrete biofilms by performing sequence analysis of 16S rDNA concrete clone libraries. ...

  11. 29 CFR 1926.704 - Requirements for precast concrete.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 8 2014-07-01 2014-07-01 false Requirements for precast concrete. 1926.704 Section 1926..., DEPARTMENT OF LABOR (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Concrete and Masonry Construction § 1926.704 Requirements for precast concrete. (a) Precast concrete wall units, structural...

  12. 29 CFR 1926.704 - Requirements for precast concrete.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 8 2010-07-01 2010-07-01 false Requirements for precast concrete. 1926.704 Section 1926..., DEPARTMENT OF LABOR (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Concrete and Masonry Construction § 1926.704 Requirements for precast concrete. (a) Precast concrete wall units, structural...

  13. 29 CFR 1926.704 - Requirements for precast concrete.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 8 2012-07-01 2012-07-01 false Requirements for precast concrete. 1926.704 Section 1926..., DEPARTMENT OF LABOR (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Concrete and Masonry Construction § 1926.704 Requirements for precast concrete. (a) Precast concrete wall units, structural...

  14. 29 CFR 1926.704 - Requirements for precast concrete.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 8 2013-07-01 2013-07-01 false Requirements for precast concrete. 1926.704 Section 1926..., DEPARTMENT OF LABOR (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Concrete and Masonry Construction § 1926.704 Requirements for precast concrete. (a) Precast concrete wall units, structural...

  15. 29 CFR 1926.704 - Requirements for precast concrete.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 8 2011-07-01 2011-07-01 false Requirements for precast concrete. 1926.704 Section 1926..., DEPARTMENT OF LABOR (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Concrete and Masonry Construction § 1926.704 Requirements for precast concrete. (a) Precast concrete wall units, structural...

  16. Mechanical and physical properties of polyester polymer concrete using recycled aggregates from concrete sleepers.

    PubMed

    Carrión, Francisco; Montalbán, Laura; Real, Julia I; Real, Teresa

    2014-01-01

    Currently, reuse of solid waste from disused infrastructures is an important environmental issue to study. In this research, polymer concrete was developed by mixing orthophthalic unsaturated polyester resin, artificial microfillers (calcium carbonate), and waste aggregates (basalt and limestone) coming from the recycling process of concrete sleepers. The variation of the mechanical and physical properties of the polymer concrete (compressive strength, flexural strength, modulus of elasticity, density, and water absorption) was analyzed based on the modification of different variables: nature of the recycled aggregates, resin contents (11 wt%, 12 wt%, and 13 wt%), and particle-size distributions of microfillers used. The results show the influence of these variables on mechanical performance of polymer concrete. Compressive and flexural strength of recycled polymer concrete were improved by increasing amount of polyester resin and by optimizing the particle-size distribution of the microfillers. Besides, the results show the feasibility of developing a polymer concrete with excellent mechanical behavior. PMID:25243213

  17. Mechanical and physical properties of polyester polymer concrete using recycled aggregates from concrete sleepers.

    PubMed

    Carrión, Francisco; Montalbán, Laura; Real, Julia I; Real, Teresa

    2014-01-01

    Currently, reuse of solid waste from disused infrastructures is an important environmental issue to study. In this research, polymer concrete was developed by mixing orthophthalic unsaturated polyester resin, artificial microfillers (calcium carbonate), and waste aggregates (basalt and limestone) coming from the recycling process of concrete sleepers. The variation of the mechanical and physical properties of the polymer concrete (compressive strength, flexural strength, modulus of elasticity, density, and water absorption) was analyzed based on the modification of different variables: nature of the recycled aggregates, resin contents (11 wt%, 12 wt%, and 13 wt%), and particle-size distributions of microfillers used. The results show the influence of these variables on mechanical performance of polymer concrete. Compressive and flexural strength of recycled polymer concrete were improved by increasing amount of polyester resin and by optimizing the particle-size distribution of the microfillers. Besides, the results show the feasibility of developing a polymer concrete with excellent mechanical behavior.

  18. Mechanical and Physical Properties of Polyester Polymer Concrete Using Recycled Aggregates from Concrete Sleepers

    PubMed Central

    Carrión, Francisco; Montalbán, Laura; Real, Julia I.

    2014-01-01

    Currently, reuse of solid waste from disused infrastructures is an important environmental issue to study. In this research, polymer concrete was developed by mixing orthophthalic unsaturated polyester resin, artificial microfillers (calcium carbonate), and waste aggregates (basalt and limestone) coming from the recycling process of concrete sleepers. The variation of the mechanical and physical properties of the polymer concrete (compressive strength, flexural strength, modulus of elasticity, density, and water absorption) was analyzed based on the modification of different variables: nature of the recycled aggregates, resin contents (11 wt%, 12 wt%, and 13 wt%), and particle-size distributions of microfillers used. The results show the influence of these variables on mechanical performance of polymer concrete. Compressive and flexural strength of recycled polymer concrete were improved by increasing amount of polyester resin and by optimizing the particle-size distribution of the microfillers. Besides, the results show the feasibility of developing a polymer concrete with excellent mechanical behavior. PMID:25243213

  19. LDRD summary report. Part 1: initiation studies of thin film explosvies used for scabbling concrete. Part 2: investigation of spray techniques for use in explosive scabbling of concrete

    SciTech Connect

    Benham, R.A.; Bickes, R.W. Jr.; Grubelich, M.C.; Wackerbarth, D.E.; Brock, J.L.

    1996-11-01

    We describe a new method for the scabbling of concrete surfaces using a thin layer of explosive material sprayed onto the surfaces. We also developed a new explosive mixture that could be applied with commercial spray painting equipment. The first part of our record describes experiments that studied methods for the initiation of the sprayed explosive. We successfully initiated layers 0.36 mm thick using a commercial EBW detonator, a flying plate detonator, and by pellet impact. The second part of our report describes a survey of spray methods and tests with two commercial spray systems that we believe could be used for developing a robotic spray system.

  20. Thermophysical Properties of Hydrocarbon Mixtures

    National Institute of Standards and Technology Data Gateway

    SRD 4 NIST Thermophysical Properties of Hydrocarbon Mixtures (PC database for purchase)   Interactive computer program for predicting thermodynamic and transport properties of pure fluids and fluid mixtures containing up to 20 components. The components are selected from a database of 196 components, mostly hydrocarbons.

  1. COMPLEX MIXTURES AND GROUNDWATER QUALITY

    EPA Science Inventory

    Experience has shown that many soil and ground-water contamination problems involve complex mixtures of chemicals. his manuscript identifies and discusses, in a generic sense, some of the important processes which must be considered when dealing with complex mixtures in the subsu...

  2. Latent classiness and other mixtures.

    PubMed

    Neale, Michael C

    2014-05-01

    The aim of this article is to laud Lindon Eaves' role in the development of mixture modeling in genetic studies. The specification of models for mixture distributions was very much in its infancy when Professor Eaves implemented it in his own FORTRAN programs, and extended it to data collected from relatives such as twins. It was his collaboration with the author of this article which led to the first implementation of mixture distribution modeling in a general-purpose structural equation modeling program, Mx, resulting in a 1996 article on linkage analysis in Behavior Genetics. Today, the popularity of these methods continues to grow, encompassing methods for genetic association, latent class analysis, growth curve mixture modeling, factor mixture modeling, regime switching, marginal maximum likelihood, genotype by environment interaction, variance component twin modeling in the absence of zygosity information, and many others. This primarily historical article concludes with some consideration of some possible future developments. PMID:24477932

  3. Concrete using waste oil palm shells as aggregate

    SciTech Connect

    Basri, H.B.; Mannan, M.A.; Zain, M.F.M.

    1999-04-01

    Concrete with oil palm shells (OPS) as coarse aggregate was investigated for its workability, density, and compressive strength development over 56 days under three curing conditions. The effect of fly ash as partial cement replacement was also studied. Fresh OPS concrete was found to have better workability while its 28-day air-dry density was 19--20% lower than ordinary concrete. Compressive strength after 56 days was found to be 41--50% lower than ordinary concrete. These results were still within the normal range for structural lightweight concrete. Fly ash was found to lower the compressive strength of OPS concrete, which was the opposite of its effect on normal concrete.

  4. Mechanical properties and microstructure analysis of fly ash geopolymeric recycled concrete.

    PubMed

    Shi, X S; Collins, F G; Zhao, X L; Wang, Q Y

    2012-10-30

    Six mixtures with different recycled aggregate (RA) replacement ratios of 0%, 50% and 100% were designed to manufacture recycled aggregate concrete (RAC) and alkali-activated fly ash geopolymeric recycled concrete (GRC). The physical and mechanical properties were investigated indicating different performances from each other. Optical microscopy under transmitted light and scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectroscopy (EDX) were carried out in this study in order to identify the mechanism underlying the effects of the geopolymer and RA on concrete properties. The features of aggregates, paste and interfacial transition zone (ITZ) were compared and discussed. Experimental results indicate that using alkali-activated fly ash geopolymer as replacement of ordinary Portland cement (OPC) effectively improved the compressive strength. With increasing of RA contents in both RAC and GRC, the compressive strength decreased gradually. The microstructure analysis shows that, on one hand, the presence of RA weakens the strength of the aggregates and the structure of ITZs; on the other hand, due to the alkali-activated fly ash in geopolymer concrete, the contents of Portlandite (Ca(OH)(2)) and voids were reduced, as well as improved the matrix homogeneity. The microstructure of GRC was changed by different reaction products, such as aluminosilicate gel.

  5. Mechanical properties and microstructure analysis of fly ash geopolymeric recycled concrete.

    PubMed

    Shi, X S; Collins, F G; Zhao, X L; Wang, Q Y

    2012-10-30

    Six mixtures with different recycled aggregate (RA) replacement ratios of 0%, 50% and 100% were designed to manufacture recycled aggregate concrete (RAC) and alkali-activated fly ash geopolymeric recycled concrete (GRC). The physical and mechanical properties were investigated indicating different performances from each other. Optical microscopy under transmitted light and scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectroscopy (EDX) were carried out in this study in order to identify the mechanism underlying the effects of the geopolymer and RA on concrete properties. The features of aggregates, paste and interfacial transition zone (ITZ) were compared and discussed. Experimental results indicate that using alkali-activated fly ash geopolymer as replacement of ordinary Portland cement (OPC) effectively improved the compressive strength. With increasing of RA contents in both RAC and GRC, the compressive strength decreased gradually. The microstructure analysis shows that, on one hand, the presence of RA weakens the strength of the aggregates and the structure of ITZs; on the other hand, due to the alkali-activated fly ash in geopolymer concrete, the contents of Portlandite (Ca(OH)(2)) and voids were reduced, as well as improved the matrix homogeneity. The microstructure of GRC was changed by different reaction products, such as aluminosilicate gel. PMID:22954605

  6. Utilization of municipal solid waste bottom ash and recycled aggregate in concrete.

    PubMed

    Juric, B; Hanzic, L; Ilić, R; Samec, N

    2006-01-01

    In the combustion process of municipal solid waste (MSW), bottom ash (BA) represents the major portion of the solid residue. Since BA is composed of oxides, especially SiO(2) and CaO, the feasibility of its application in concrete as a substitute for cement was tested. It was found that at the age of 28 days, the flexural and compressive strengths of the binder linearly decrease at the rate of 0.03 and 0.02 MPa per wt% of BA in the binder, respectively. According to the results it may be recommended to replace up to 15 wt% of cement by BA and to use such binder where a low strength of concrete elements is required. Furthermore, the aggregate used for low strength concrete need not be of a very good quality. Therefore, gravel aggregate was partially replaced by recycled aggregate (RA). Consistency measured by slump was significantly reduced (>50%) when BA or/and RA were introduced into the mixture. However, concrete density and compressive strength were not affected and were approximately 2300 kg/m(3) and approximately 40 MPa, respectively.

  7. Linear viscoelastic limits of asphalt concrete at low and intermediate temperatures

    NASA Astrophysics Data System (ADS)

    Mehta, Yusuf A.

    The purpose of this dissertation is to demonstrate the hypothesis that a region at which the behavior of asphalt concrete can be represented as a linear viscoelastic material can be determined at low and intermediate temperatures considering the stresses and strains typically developed in the pavements under traffic loading. Six mixtures containing different aggregate gradations and nominal maximum aggregate sizes varying from 12.5 to 37.5 mm were used in this study. The asphalt binder grade was the same for all mixtures. The mixtures were compacted to 7 +/- 1% air voids, using the Superpave Gyratory Compactor. Tests were conducted at low temperatures (-20°C and -10°C), using the indirect tensile test machine, and at intermediate temperatures (4°C and 20°C), using the Superpave shear machine. To determine the linear viscoelastic range of asphalt concrete, a relaxation test for 150 s, followed by a creep test for another 150 s, was conducted at 150 and 200 microstrains (1 microstrain = 1 x 10-6), at -20°C, and at 150 and 300 microstrains, at -10°C. A creep test for 200 s, followed by a recovery test for another 200 s, was conducted at stress levels up to 800 kPa at 4°C and up to 500 kPa at 20°C. At -20°C and -10°C, the behavior of the mixtures was linear viscoelastic at 200 and 300 microstrains, respectively. At intermediate temperatures (4°C and 20°C), an envelope defining the linear and nonlinear region in terms of stress as a function of shear creep compliance was constructed for all the mixtures. For creep tests conducted at 20°C, it was discovered that the commonly used protocol to verify the proportionality condition of linear viscoelastic behavior was unable to detect the appearance of nonlinear behavior at certain imposed shear stress levels. Said nonlinear behavior was easily detected, however, when checking the satisfaction of the superposition condition. The envelope constructed for determining when the material becomes nonlinear should be

  8. Maintenance and preservation of concrete structures. Report 3: Abrasion-erosion resistance of concrete

    NASA Astrophysics Data System (ADS)

    Liu, T. C.

    1980-07-01

    This report describes a laboratory test program on abrasion-erosion resistance of concrete, including the development of a new underwater abrasion-erosion test method. This program was designed to evaluate the relative abrasion-erosion resistance of various materials considered for use in the repair of erosion-damaged concrete structures. The test program encompassed three concrete types (conventional concrete, fiber-reinforced concrete, and polymer concrete); seven aggregate types (limestone, chert, trap rock, quartzite, granite, siliceous gravel, and slag); three principal water-cement rations (0.72, 0.54, and 0.40); and six types of surface treatment (vacuum, polyurethane coating, acrylic mortar coating, epoxy mortar coating, furan resin mortar coating, and iron aggregate topping). A total of 114 specimens made from 41 batches of concrete was tested. Based on the test data obtained, a comprehensive evaluation of the effects of various parameters on the abrasion-erosion resistance of concrete was presented. Materials suitable for use in the repair of erosion-damaged concrete structures were recommended. Additional work to correlate the reported findings with field performance was formulated.

  9. Electro-osmotic techniques for removal of chloride from concrete and for emplacement of concrete sealants

    NASA Astrophysics Data System (ADS)

    Jayaprakash, G. P.; Bukovatz, J. E.; Ramamurti, K.; Gilliland, W. J.

    1982-08-01

    Chloride ion from bridge deck concrete can be removed by application of a direct current potential between bridge reinforcing steel (-) and a copper screen (+) conductor on the bridge surface. Soaring prices of all types of energy would make removal of all chloride prohibitatively expensive. The importance of verification of all electrical connections prior to the treatment is emphasized by the demonstration of concrete cracking when the steel was made a positive instead of a negative electrode. Data on effectiveness of calcium nitrite corrosion inhibitor added to the concrete overlay placed on electrotreated concrete is not extensive due to accidental damage to the test slabs.

  10. Use of incinerator bottom ash in concrete

    SciTech Connect

    Pera, J.; Coutaz, L.; Ambroise, J.; Chababbet, M.

    1997-01-01

    The aim of the present work was to show if municipal solid waste incinerator (MSWI) bottom ash could be an alternative aggregate for the production of building concrete presenting a characteristic 28-day compressive strength of 25 MPa. The aggregates passing the 20-mm sieve and retained on the 4-mm sieve were considered for investigation. They showed lower density, higher water absorption, and lower strength than natural gravel. They could be considered as average quality aggregates for use in concrete. When directly introduced in concrete, they led to swelling and cracking of specimens, due to the reaction between cement and metallic aluminium. Therefore, a treatment by sodium hydroxide was proposed to avoid such degradation, which made possible the partial replacement (up to 50%) of gravel in concrete without affecting the durability.

  11. Electrical conductivity of concrete containing silica fume

    SciTech Connect

    Abo El-Enein, S.A.; Kotkata, M.F.; Hanna, G.B.; Saad, M.; Abd El Razek, M.M.

    1995-12-01

    The influence of silica fume on concrete properties represents an important technical research. In general, silica fume tends to improve both mechanical characteristics and durability of concrete. Thus the electrical properties of concrete containing silica fume can be studied to clarify its physical performance during hydration. The electrical conductivity of neat cement, mortar and concrete pastes was measured during setting and hardening. The ordinary Portland cement was partially replaced by different amounts of silica fume by weight. The changes in the electrical conductivity were reported during setting and hardening after gauging with water. The results of this study showed that the electrical conductivity can be used as an indication for the setting characteristics as well as the structural changes of the hardened pastes made with and without silica fume.

  12. Concrete "Waffle" Provides Laser Beam Accuracy

    ERIC Educational Resources Information Center

    Building Design and Construction, 1978

    1978-01-01

    A massive concrete "waffle," riding on a bed of specially treated gravel and sand inside another building, provides the structural rigidity needed by the University of Rochester's Laboratory for Laser Energetics. (Author)

  13. Seismic safety of high concrete dams

    NASA Astrophysics Data System (ADS)

    Chen, Houqun

    2014-08-01

    China is a country of high seismicity with many hydropower resources. Recently, a series of high arch dams have either been completed or are being constructed in seismic regions, of which most are concrete dams. The evaluation of seismic safety often becomes a critical problem in dam design. In this paper, a brief introduction to major progress in the research on seismic aspects of large concrete dams, conducted mainly at the Institute of Water Resources and Hydropower Research (IWHR) during the past 60 years, is presented. The dam site-specific ground motion input, improved response analysis, dynamic model test verification, field experiment investigations, dynamic behavior of dam concrete, and seismic monitoring and observation are described. Methods to prevent collapse of high concrete dams under maximum credible earthquakes are discussed.

  14. Concrete hulls for tension-leg platforms

    SciTech Connect

    De Oliveira, J.G. ); Fjeld, S. )

    1990-06-01

    This paper describes the main features of a concrete-hull tension-leg-platform (TLP) concept developed for the Heidrun field in the Haltenbanken area of the Norwegian sector of the North Sea. The hydrodynamic response and the methods adopted to optimize the hull dimensions, as well as the mooring system and hull mechanical outfitting, are discussed first. Then construction methods are briefly described. Inspection, maintenance, and repair are also addressed. Finally, the advantages of the concrete-hull TLP concept are summarized, including the concrete hull's adaptability to a large range of design requirements, low cost, and short construction time. This paper shows that the concrete-hull TLP is a very cost-efficient solution for the development of deepwater fields.

  15. Laboratory constitutive characterization of cellular concrete.

    SciTech Connect

    Hardy, Robert Douglas; Lee, Moo Yul; Bronowski, David R.

    2004-03-01

    To establish mechanical material properties of cellular concrete mixes, a series of quasi-static, compression and tension tests have been completed. This report summarizes the test methods, set-up, relevant observations, and results from the constitutive experimental efforts. Results from the uniaxial and triaxial compression tests established failure criteria for the cellular concrete in terms of stress invariants I{sub 1} and J{sub 2}. {radical}J{sub 2} (MPa) = 297.2 - 278.7 exp{sup -0.000455 I}{sub 1}{sup (MPa)} for the 90-pcf concrete {radical}J{sub 2} (MPa) = 211.4 - 204.2 exp {sup -0.000628 I}{sub 1}{sup (MPa)} for the 60-pcf concrete

  16. Exploring Floating Concrete and Beam Design.

    ERIC Educational Resources Information Center

    Snell, Billie G.; Snell, Luke M.

    2002-01-01

    Presents two construction activities that address both state and federal science standards and encourage students to consider career options in mathematics and science. Includes floating concrete and paper bridge activities. (YDS)

  17. Pentek concrete scabbling system: Baseline report

    SciTech Connect

    1997-07-31

    The Pentek scabbling technology was tested at Florida International University (FIU) and is being evaluated as a baseline technology. This report evaluates it for safety and health issues. It is a commercially available technology and has been used for various projects at locations throughout the country. The Pentek concrete scabbling system consisted of the MOOSE{reg_sign}, SQUIRREL{reg_sign}-I, and SQUIRREL{reg_sign}-III scabblers. The scabblers are designed to scarify concrete floors and slabs using cross-section, tungsten carbide tipped bits. The bits are designed to remove concrete in 318 inch increments. The bits are either 9-tooth or demolition type. The scabblers are used with a vacuum system designed to collect and filter the concrete dust and contamination that is removed from the surface. The safety and health evaluation during the human factors assessment focused on two main areas: noise and dust.

  18. Sequestration of CO2 by concrete carbonation.

    PubMed

    Galan, Isabel; Andrade, Carmen; Mora, Pedro; Sanjuan, Miguel A

    2010-04-15

    Carbonation of reinforced concrete is one of the causes of corrosion, but it is also a way to sequester CO2. The characteristics of the concrete cover should ensure alkaline protection for the steel bars but should also be able to combine CO2 to a certain depth. This work attempts to advance the knowledge of the carbon footprint of cement. As it is one of the most commonly used materials worldwide, it is very important to assess its impact on the environment. In order to quantify the capacity of cement based materials to combine CO2 by means of the reaction with hydrated phases to produce calcium carbonate, Thermogravimetry and the phenolphthalein indicator have been used to characterize several cement pastes and concretes exposed to different environments. The combined effect of the main variables involved in this process is discussed. The moisture content of the concrete seems to be the most influential parameter. PMID:20225850

  19. Ulexite-galena intermediate-weight concrete as a novel design for overcoming space and weight limitations in the construction of efficient shields against neutrons and photons.

    PubMed

    Aghamiri, S M R; Mortazavi, S M J; Razi, Z; Mosleh-Shirazi, M A; Baradaran-Ghahfarokhi, M; Rahmani, F; Faeghi, F

    2013-01-01

    Recently, due to space and weight limitations, scientists have tried to design and produce concrete shields with increased attenuation of radiation but not increased mass density. Over the past years, the authors' had focused on the production of heavy concrete for radiation shielding, but this is the first experience of producing intermediate-weight concrete. In this study, ulexite (hydrated sodium calcium borate hydroxide) and galena (lead ore) have been used for the production of a special intermediate-weight concrete. Shielding properties of this intermediate-weight concrete against photons have been investigated by exposing the samples to narrow and broad beams of gamma rays emitted from a ⁶⁰Co radiotherapy unit. Densities of the intermediate-weight concrete samples ranged 3.64-3.90 g cm⁻³, based on the proportion of the ulexite in the mix design. The narrow-beam half-value layer (HVL) of the ulexite-galena concrete samples for 1.25 MeV ⁶⁰Co gamma rays was 2.84 cm, much less than that of ordinary concrete (6.0 cm). The Monte Carlo (MC) code MCNP4C was also used to model the attenuation of ⁶⁰Co gamma-ray photons and Am-Be neutrons of the ulexite-galena concrete with different thicknesses. The ⁶⁰Co HVL calculated by MCNP simulation was 2.87 cm, indicating a good agreement between experimental measurements and MC simulation. Furthermore, MC-calculated results showed that thick ulexite-galena concrete shields (60-cm thickness) had a 7.22 times (722 %) greater neutron attenuation compared with ordinary concrete. The intermediate-weight ulexite-galena concrete manufactured in this study may have many important applications in the construction of radiation shields with weight limitations such as the swing or sliding doors that are currently used for radiotherapy treatment rooms.

  20. Ulexite-galena intermediate-weight concrete as a novel design for overcoming space and weight limitations in the construction of efficient shields against neutrons and photons.

    PubMed

    Aghamiri, S M R; Mortazavi, S M J; Razi, Z; Mosleh-Shirazi, M A; Baradaran-Ghahfarokhi, M; Rahmani, F; Faeghi, F

    2013-01-01

    Recently, due to space and weight limitations, scientists have tried to design and produce concrete shields with increased attenuation of radiation but not increased mass density. Over the past years, the authors' had focused on the production of heavy concrete for radiation shielding, but this is the first experience of producing intermediate-weight concrete. In this study, ulexite (hydrated sodium calcium borate hydroxide) and galena (lead ore) have been used for the production of a special intermediate-weight concrete. Shielding properties of this intermediate-weight concrete against photons have been investigated by exposing the samples to narrow and broad beams of gamma rays emitted from a ⁶⁰Co radiotherapy unit. Densities of the intermediate-weight concrete samples ranged 3.64-3.90 g cm⁻³, based on the proportion of the ulexite in the mix design. The narrow-beam half-value layer (HVL) of the ulexite-galena concrete samples for 1.25 MeV ⁶⁰Co gamma rays was 2.84 cm, much less than that of ordinary concrete (6.0 cm). The Monte Carlo (MC) code MCNP4C was also used to model the attenuation of ⁶⁰Co gamma-ray photons and Am-Be neutrons of the ulexite-galena concrete with different thicknesses. The ⁶⁰Co HVL calculated by MCNP simulation was 2.87 cm, indicating a good agreement between experimental measurements and MC simulation. Furthermore, MC-calculated results showed that thick ulexite-galena concrete shields (60-cm thickness) had a 7.22 times (722 %) greater neutron attenuation compared with ordinary concrete. The intermediate-weight ulexite-galena concrete manufactured in this study may have many important applications in the construction of radiation shields with weight limitations such as the swing or sliding doors that are currently used for radiotherapy treatment rooms. PMID:23019599