bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hot Pressed DSP Cement Paste
Authors: Lu Ping , Young J. Francis 
Published: March 2011

ABSTRACTDSP cement paste is prepared by hot-pressing technique in this study in order to improve its particle packing and chemical composition, and to investigate the relationship between its solid phase microstructure and mechanical strength at the porosity close to zero. The addition of silica fume improves strength development, although capillary porosities are not changed significantly. Results obtained indicate that the highest compressive strength reached are 800 MPa after 28 days hydration and oven drying at 200°C. The strength has better relation with degree of hydration or the physical density of C-S-H. the silicate anion polymerization closes not appear to influence strength.
Durability of High-Performance Cement-Based Materials
Authors: Struble Leslie , Garboczi Edward , Clifton James 
Published: March 2011

ABSTRACTThere is considerable research now underway on high-performance cement-based materials, in particular on issues of processing, microstructure, strength, and related properties. However, very little research has been undertaken regarding the durability, or service performance, of these materials. Therefore the durability of high-performance cement-based materials can only be inferred from the service performance of ordinary materials or from a basic understanding of the factors affecting service performance. In this paper we review what is known about the durability of fiber reinforced concrete, high performance concrete, DSP, and MDF. Durability is discussed from the standpoint of general issues – fluid permeability, ionic diffusivity, and pore fluid composition. Much research is needed in order to predict or improve the durability of high performance cement-based materials.
Advanced Methods of Concrete Characterization
Authors: Lee R. J. , Draper E. A. , Skalny J. 
Published: March 2011

ABSTRACTThe need for the rehabilitation of the infrastructure has lead to the adaptation of modem analytical methods for the characterization of concrete. These techniques are not commonly associated with evaluating concrete but promise to be very useful both as tools of quality assurance and in the determination of existing damage. This paper describes two such techniques, namely, coordinated electron-optical microscopy and gamma-ray tomography. Examples of the use and interpretation of each method are given.
Tensile Strength of Carbon Fiber Reinforced Cement Composites
Authors: Toutanji Houssam A. , Korchi Tahar El- , Leatherman Gary L. , Katz R. Nathan 
Published: March 2011

ABSTRACTThe effect of carbon fibers on the uniaxial tensile strength of cement paste matrix is studied. The tensile strength values are obtained using the novel Cementitious Composites Axial Tensile Technique (CCATT) described previously [1]. The addition of 1.0, 1.5 and 2.0 volume percent of Polyacrylonitrile-based (PAN) carbon fiber results in an increase in tensile strength of 32, 41 and 48 percent respectively, as compared to the unreinforced matrix. A model based on the rule of mixtures is used to predict the tensile strength of the carbon fiber reinforced composites. Results are discussed with respect to fiber, interface bond, and cementitious matrix characteristic.
Characterization of Gas Reburning-Sorbent Injection Technology By-Products
Authors: Mattigod Shas V. , Rai Dhanpat 
Published: March 2011

ABSTRACTThree samples of fly ashes from pilot-scale tests of gas reburning and sorbent injection (GR-SI) technology were characterized physically, chemically, and mineralogically. Texturally, the samples consist of approximately 97% by weight of silt-size particles. Total chemical analysis showed that Al, Ca, C, Fe, Si, and S were the major elements, making up 56% of the total mass of the sample on average. Approximately 3% of the sample mass consisted of the elements Cl, Mg, P, K, Na, and Ti, and 0.4% consisted of trace elements. Major crystalline compounds found in these samples were lime (CaO), anhydrite (CaSO4), and calcium carbonate (CaCO3). Calculations show that these compounds constituted from 56 to 76% of the mass of the samples. The morphology and chemistry of particles in GR-SI samples were similar to those of particles in conventional coal fly ashes. The particles in the GR-SI samples consisted of fragments and spheres of varying sizes. Most of the particles were calcareous. Silicate and alumino-silicate particles were fewer in number, and iron-rich particles were rare. The EP test indicated that extract concentrations of Ag, As, Ba, Cd, Cr, Pb, and Se were well below the EPA regulatory levels. Predictions of leachate compositions from these types of fly ashes, if disposed of as a landfill at a midwestern U.S. site indicate, that during the first ten years the concentrations of Ca, SO4, Na, B, and OH would remain high. The concentrations of minor constituents (As, Ba, Cd, Cd, Cu, Cr, Fe, Ni, and Se) in the leachate are predicted to be at trace levels.
An Investigation of Fluidized Bed Combustion By-Products from Four Iowa Power Plants
Authors: Kilgour Carol L. 
Published: March 2011

ABSTRACTFluidized bed combustion (FBC) residues from four Iowa power plants were characterized to provide background with respect to chemical, physical, mineralogical and microstructural parameters that might affect their utilization potential. Methodologies used include: bulk chemical analysis; grain size analysis; specific gravity determination; mineralogical analysis by x-ray diffraction; scanning electron microscopy; and thermal analysis.Chemical analysis of the major components showed the separation of the constituents during combustion. The bottom ash is derived from the calcined and partly sulfated limestone, thus the concentration of calcium and sulfur compounds is greater. The fly ash however is derived mostly from the coal and therefore exhibits higher concentrations of coal ash components such as silica (SiO2), alumina (Al2O3), and ferric oxide (Fe2O3). The alkalis appear to be more concentrated in the fly ash.The measured particle size distributions of the bulk samples varied greatly, from extremely coarse (mean particle size ˜2000 μm) to fine (mean particle size ˜25 μm). The size distributions also varied in breadth. Specific gravities values recorded ranged from about 2.65 to about 3.05.X-ray diffraction analyses showed that most of the FBC by-products contain, as easily detectable crystalline components, only quartz, anhydrite and lime, and as is to be expected due to the low combustion temperatures, do not show broad peaks characteristic of glass in conventional fly ashes. Scanning electron microscopy revealed the FBC by-products to be extremely intricate mixtures of particles of complex and variable composition and internal structure.FBC by-products are shown to be extremely complex mixtures of particles of variable composition and internal structure. However, despite their local variation, useful results can be obtained by overall chemical and physico-chemical analyses of their composition. The exploitable properties of FBC residue include the somewhat cementitious nature and the granularity. However, their heterogeneous nature, lack of pozzolanic properties, and elevated sulfate content may limit their uses, especially in construction.
Treatment of Acid Mine Drainage Water Using Fly Ash and Water Softening Sludge
Authors: Atalay Asmare , Chaluvadi Srinivas , Laguros Joakim G. , Black Jerry J. 
Published: March 2011

ABSTRACTAcid mine drainage (AMD) is being recognized as a major pollution source to surface water. Heavy trace metals emanating from abandoned mines are continuously being released and contaminating surrounding lakes and streams. The potential for utilizing fly ash and water softening sludge (WSS) as buffering and adsorption media for AMD water was assessed. The results indicated that AMD water treated with fly ash either met or exceeded the U.S. Environmental Protection Agency water quality criteria for effluent standards for total iron, manganese, suspended solids, and pH. The optimum dosage of fly ash and sludge needed for treating the acid mine water from Picher field, an abandoned lead and zinc mine in Oklahoma, has been determined. It was observed that each had better than 90 percent efficiency for removal of heavy metals from the AMD water. The combined use of fly ash and WSS was also investigated, but there was no significant improvement compared to using fly ash alone. In general fly ash had a greater buffering capacity to treat acid mine water than did WSS. Consequently, fly ash can be used to treat AMD water and minimize its environmental impact.
Investigation in the System “Portland Clinker-Gypsum Plaster-Condensed Silica”
Authors: Odler I. , Balzer M. 
Published: March 2011

ABSTRACTBlends of portland clinker and gypsum plaster exhibit fast setting and early strength development if mixed with water. An excessive expansion of such systems may be controlled by the use of a “sulfate resistant” rather than “ordinary” clinker and by adding condensed silica to the system. The water resistance of such hardened pastes is significantly improved as compared to plain gypsum pastes, mainly due to the formation of the C-S-H-and AFt-phases.
Diffuse Yield drop and Snap Action in a Ni-Ti Alloy
Authors: Duerig T.W. , Melton K.N. 
Published: March 2011

AbstractAn unusual yield phenomenon is observed in a heavily worked NiTiFe alloy, which leads to snap action shape memory and superelasticity. The snap action occurs at extremely high velocities and is accompanied by a loud cracking sound. The cause of the instability is attributed to penning, in which martensite growth is halted by having to undergo a reorientation at low angle cell boundaries, which then lowers the resolved shear stress on the martensite plate. Once free of the cell boundary, the plate grows and its strain energy is reduced so that it is able to penetrate subsequent boundaries more easily. This results in a diffuse yield drop, and the said snap action motion.
Microstructural Features and Shape-Memory Characteristics of Melt-Spun Ni-Al-Fe-B Ribbons
Authors: Liu C. T. , Sparks C. J. , Horton J. A. , George E. P. , Carmichael C. A. , Kao Ming-Yuan , Kunsmann Henry 
Published: March 2011

AbstractThis paper summarizes our recent study of NiAI+Fe+B alloy ribbons containing 4 to 20% Fe and doped with 300 wt ppm B. Alloy ribbons were successfully fabricated by rapid solidification via melt spinning. The alloys with 8% Fe and 34% Al-equivalent [=Al%+(Fe%)/2] showed the best bend ductility at room temperature. The ribbons exhibited a reversible martensite (body-centered orthorombic structure) to B2 transformation as evidenced by DSC, X-ray and TEM studies. The shape-memory effect, as characterized by measuring the recovery of bend angles with temperature, is sensitive to alloy composition, with the best recovery observed in SMA-15 (B-doped Ni-27% Al-14% Fe). Annealing at 600°C causes aging embrittlement; in particular, in alloys containing 12% Fe.
Microstructural Characteristics and Shape Memory Effect of Rapidly Quenched Cu-Al-Ni-Cr Alloy
Authors: Koo Horng-Show , Chen Hsing , Chen Fu-Hsing 
Published: March 2011

AbstractCuAlNiCr shape memory alloy ribbons with thickness ranging from 65 to 60 pm and about 15–20 mm width have been produced by melt-spinnig technique. Finer grain and homogenous columnar structure could be examined. Transformation temperatures and grain size of CuAlNiCr alloy increase with increasing heat treatment time. The reversible color change phenomena( red copper color=bronze color ) associated with phase transformation in alloy ribbons was also observed. Microstructural and transformation characteristics of rapidly quenched CuAlNiCr alloys were observed by x-ray diffraction, optical microscope, four-probe electrical resistivity method, scanning and transmission microscope.
Shape Memory Effect Due to Phaselike Transition in High Tc Superconductors
Authors: Wang Y.N. , Shen H.M. , Zhu M. , Huang Y.N. , Zhang Z.F. , Liu Z.M. , Fung P.C.W. 
Published: March 2011

AbstractTensil tests for YBaCuO, Bi(Pb)SrCaCuO and TiBaCaCuO show that there always appear ferroelastic loops and shape memory effect due to the phaselike transition at tens degrees above Tc (<150K), which disappear for nonsuperconducting YBaCuO, Y(Pr)BaCuO and CuO. The property of the phaselike transition and the discrepancy on the internal friction peaks near Tc for YBaCuO have been studied and discussed.
Production and Characterization of FE-NI-CO-TI Shape Memory Springs with One- and Two-Way Effect
Authors: Jost Norbert 
Published: March 2011

AbstractIt has been shown that ausaged Fe-Ni-Co-Ti alloys exhibit a reversible martensitic transformation with a small temperature hysteresis between the forward and the reverse transformation. This is due to the precipitation of small coherent (Ni,Co,Fe)3Ti particles. On the one hand they lead to a very effective precipitation hardening of the austenite and on the other hand to high elastic back stresses after shearing together with the martensite into a metastable structure. The martensitic morphology in such states is typically lathlike (thin plate martensite).While yield stress and tensile strength increase during ausaging, the toughness, especially the elongation at fracture changes for the worse. The results of this work show that this can be prevented by a combined thermo-mechanical treatment. At the same time a remarkable twoway shape memory effect can be observed.For practical applications the use of springs seems the best way for this type of Fe-based alloys because the recovery strain is low in comparison to Ni-Ti alloys. On the other side, due to the special transformation mechanism in Fe-Ni-Co-Ti alloys it can be assumed that the possible power in the two-way-effect should nearly reach the value of that obtained in binary Ni-Ti alloys.Mechanical and thermal properties of different springs made from Fe-Ni-Co-Ti shape memory alloys were studied by means of special deformation tests. Thereby, the maximum obtainable power in the reversible shape-memory effect of the investigated springs was of special interest. The martensite morphologies were investigated by optical-microscopy.
Hrem Studies of Rapidly Solidified Ni-Fe-Al-B Shape Memory Alloys.
Authors: Pērez R. , Juārez-Islas J. A. , Johansson P. , Wallin M. , Savage S. J. 
Published: March 2011

AbstractA series of (NixFeyAlz)0.9983B0.0017 (where x=58-60, y=13-15 and z=26-28, in at%) alloys have been rapidly solidified by - melt spinning. The ribbons have been characterized by HREM, DSC, X-ray diffraction and recoverable strain measurements. The as-cast alloys exhibit excellent bend ductility (in contrast to B2 type alloys conventionally cast) and a wide range of transformation temperatures: Ms=244-466 K, Mf=200-395K, As=236-427K and Af=262-526K. X-ray diffraction shows the presence of β (NiAl), β′ (NiAl), γ (Ni3Al), γ′ (Ni3A1), Ni and other phases such as Fe3Al, FeAl, FeNi and Al5Fe2. It is the β- β′ diffusionless transformation which is responsible for the shape memory effect. The results obtained by transmission electron microscopy (TEM) show two different types of crystalline grains. In one case, the grains have a high density of twins which are the fingerprints of the martensite transformation. However, other areas in the specimen show crystalline grains with very poor image contrast due to the transformation from β′ -β. There are also sections in the specimens with domains of both crystalline sgrains in coexistance. Both crystalline grains have large amounts of precipitates. In the β′ (NiAl) phase the size of the precipitates range fron lnm to lOnm. In the γ (Ni3Al) phase large precipitates (20nm) can be found. Some of them display pentagonal shapes which resemble the image contrast obtained in the TEM for small icosahedral metallic particles. Experimental evidence is also obtained on different habit or twin planes. HREM images from the twinned areas suggest diferent kinds of atomic structures for the parent and martensite crystalline sections. These results give some insights into the nature of the martensite transformation.
Mass Production of Thermomarkers
Authors: Raymond M. , Pothet J.B. , Weynant E. 
Published: March 2011

AbstractThe Thermomarker is the first industrial application of copper based shape memory alloys which knows a very large spreading. It's a tester that gives a signal very easy to read. However it is a precision instrument and its testing remains an essential care.The paper will explain the special feature of the Thermomarker which falls in with two tests of working: one during the martensite → austenite transformation, one during the austenite → martensite transformation. We shall expose what kind of working test (in fact a screening inspection) we have set up to get a good accuracy and a whole reliability even on a mass production.Then we shall expose our system of production tracing that is able to trace back the whole historical account of any Thermomarker.
An Apparatus for Extinguishing a Lighted Cigarette.
Authors: Koo Horng-Show , Chang Li , Chen Hsing , Shieh Kai-Liang 
Published: March 2011

AbstractAn apparatus for extinguishing a lighted cigarette comprises a hollow housing and a cigarette ash storage chamber. A cutter for cutting and extinguishing the burning portion of a lighted cigarette is provided within the housing comprising a bias spring and two pieces of shape memory alloys having different temperature reaction gradients, wherein one of the shape memory alloys is used in the cutter and the other is used in a L-shaped gate. When the burning portion of a cigarette is placed into the inside of the housing and comes into contact with the cutter, the cutter will restore to its memory shape by the temperature response to cut the burning portion of the lighted cigarette and to extinguish the burning portion by pressing it on the gate. Then, the gate will stretch straight to let the cigarette ash drop into the storage container by the temperature response. When the temperature of the gate is decreased, the gate will recover to its original position to cover the storage container, thus, the cigarette ash is restricted within the storage chamber to prevent it from dispersing and cause pollution. If a lighter is attached with the apparatus, it facilitates carrying and provides a safe and clean environment.
Stability and Phase Behavior of Mixed-Surfactant Vesicles
Authors: Mackintosh F. C. , Safran S. A. 
Published: March 2011

AbstractWhile ideal fluid membranes are characterized solely by curvature elasticity, many structural (“external”) properties of real membranes are strongly influenced by “internal degrees of freedom”. In particular, recent experimental reports of stable vesicles in surfactant mixtures seem to illustrate the important interplay between composition and curvature in bilayer membranes. Such stable vesicles are unexpected in single-surfactant bilayers. We show theoretically how the energetic stabilization of mixed vesicles can occur in mixed-surfactant systems. This is illustrated by a microscopic model of mixed-surfactant bilayers, which is treated within both the random mixing and strongly interacting limits. The predictions of the ranges of stability of the various phases as a function of the three concentrations (solvent - e.g., water - and the two amphiphiles) is in qualitative agreement with recent experiments.In addition, we consider the effect of phase separation in a mixed-surfactant system. In contrast with a bulk system, we find that for a binary mixture in a two dimensional fluid bilayer membrane, phase separation determines a length scale for the formation of stable vesicles. This results in a stable, one phase vesicle region near the critical composition, with a simple dependence of the vesicle size on composition. We also find regions of coexistence of vesicles with lamellae.
Melt Diffusion in Model Liquid Crystalline Polyiers
Authors: Hall E. , Ober C.K. , Kramer E.J. , Colby R.H. , Gillmor J.R. , Galli G. 
Published: March 2011

AbstractDiffusion of model main-chain and side-chain liquid crystalline polymers was studied in the nematic phase. The concentration of deuterium labeled polymer vs. depth in a thick matrix layer was profiled with Forward Recoil Spectrometry to determine diffusion coefficients. In each system, the tracer diffusion coefficient was measured as a function of temperature, and correlated both with phase transitions determined by thermal analysis and with melt viscosity data.
Rheo-Optiics for Multicomponent Liquids
Authors: Fuller G. , van Egmond J. , Zawada J. , Archer L. 
Published: March 2011

AbstractThe application of techniques in optical rheometry for the study of multicomponent systems is reviewed. Small angle light scattering (SALS) patterns are related to the structure of concentration fluctuations with length scales of the order of the wavelength of light. Scattering techniques such as SALS and scattering dichroism have been applied to monitor the transient evolution of anisotropic concentration fluctuation enhancement during simple shear induced phase separation in a semi-dilute solution of polystyrene (PS) in dioctyl phthalate(DOP). Furthermore, the Onuki- Doi theory relating scattering dichroism and structure factor has been used to verify the consistency between scattering dichroism and anisotropy in structure factor. Infrared polarimetry is a useful technique in probing the transient microstructural orientation of individual chemical species in multicomponent systems. The simultaneous measurement of intrinsic infrared dichroism and birefringence is particularly effective and has been employed to monitor component relaxation dynamics in miscible blends of poly(ethylene oxide) and poly(methyl methacrylate). Polarization Modulated Laser Raman Scattering (PMLRS) has been successfully employed to study the orientation dynamics of a polymer melt subjected to transient uniaxial extension. PMLRS provides quantitative information about the time evolution of both the second and fourth moments of the orientation distribution function of molecular segments.
Does Shear-Flow Enhance or Suppress Fluctuations in Shectics?
Authors: Bruinska R. , Rabin Y. 
Published: March 2011

AbstractWe investigate the effects of shear-flow on the smectic phase of thermotropic and lyotropic liquid crystals. We show that shear-flow transforms a Smectic-A thermotropic into an orthorombic solid by the suppression of undulation fluctuations. In contrast, the lyotropic Lαphase exhibits, in addition, a very striking enhancement of shortwavelength concentration fluctuations - a phenomenon which is closely analogous to a well-known effect in polymer solutions. We demonstrate this result using both hydrodynamic theory as well as a microscopic model based on the Helfrich theory of membranes. The dispersion relation of the concentration fluctuations is in qualitative agreement with recent experiments on the Lαphase in shear flow.
Nucleation and Growth of Liquid Droplets Under a Shear Flow
Authors: Perrot F. , Baumberger T. 
Published: March 2011

AbstractPhase separation in an off-critical binary mixture is studied under an uniform and steady shear flow. The nucleation and subsequent growth of droplets in aweakly supersaturated mixture (volume fraction of the new phase smaller than 10%) is studied by small angle scattering and turbidity measurements. The completion of the nucleation process is shown to be accelerated by the shear flow. At very low supersaturation, a strong effect of shear is detected which can be related to shear-triggered nucleation. In situ measurements ’of the surface tension between the two phase-separating phases obtained by studying the deformation and tilt of the growing droplets is discussed.