bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Chemical Image Analysis Method for Portland Cements
Authors: Diamond Sidney , Bonen David 
Published: March 2011

ABSTRACTA method is described for carrying out image analysis on portland cements in which the differing chemical compositions of the particles are specifically recognized. Representative fields of ca. 100 individual particles are imaged by a backscatter detector in an SEM, then ported to the attached image analyzer. After preliminary procedures, the image analyzer takes control of the SEM and individually rasters over each particle in turn to acquire both chemical (EDX) and geometrical information. The recorded EDX spectra are used to automatically assign each particle to its predominant mineralogical phase At the same time, conventional feature analysis parameters are acquired for each particle, including measurements of area, length, width, perimeter, shape, etc. The results of the analysis of a given cement constitutes a data base of all of the particles analyzed. It can be used to provide global characterization, or features can be broken out by size class, mineralogical type, shape, or various combinations of parameters. Illustrations are provided of the results of such analysis for a cement, and possible applications to clinker, cement paste, and concrete are considered.
Strength and Microstructural Properties of Water Glass Activated Slag
Authors: Qing-Hua Cheng , Tagnit-Hamou Arezki , Sarkar Shondeep L. 
Published: March 2011

ABSTRACTSlag as a supplementary cementitious material is known for its latent hydraulic properties. Thus, constant efforts are being directed towards improving its reactivity. This mostly involves the use of alkali salts. The authors present the results of alkali activation of a slag from Hamilton, Ontario, Canada, by means of water glass (Na2SiO3). Distinct improvement in early and late age strength was noted when water glass was used in combination with CH. The microstructure of this activated slag paste at 28 days is described. The microanalytical techniques used included SEM/EDXA, and XRDA.
Hydration Reactions and Etrringite Formation in Selected Cementitious Coal Conversion By-Products
Authors: Solem Jody K. , McCarthy Gregory J. 
Published: March 2011

ABSTRACTCementitious reactions and ettringite formation, which occur when water is added to high-calcium fly ash, to many dry flue gas desulfurization solids, and to two of the residues from the emerging “clean coal” technologies, fluidized bed combustion and limestone injection multiphase burner, have been studied. The parameters varied included water to solid ratio and curing time. Crystalline reactants and products were monitored by X-ray powder diffraction. The amount of ettringite, the principal crystalline cementitious reaction product, was determined after three months of curing. Results are discussed in terms of available Ca, Al and S in each by-product and w/s ratio.
Deformation Twinning, Slip, Martensite Formation and Crack Inhibition in the B2-Type Zr50Pd35Ru15 Alloy
Authors: Waterstrat R.M. , Bendersky L.A. , Kuentzler R. 
Published: March 2011

AbstractEnhanced room temperature toughness of the Zr50Pd35Ru15B2 phase alloy was found to be a result of the activation of an additional deformation mode besides the b=[001] dislocation slip mode - {114}-type mechanical twinning. The twinning is a true one, i.e. there is no change in the ordered crystal structure. Another additional mode of plastic deformation, expected for more Pd rich alloys, is the formation of stress-induced martensite. The martensite was found to have a CrBtype structure.
Microstructure, Phase Stability, Mechanical Properties, and Shape Memory Characteristics of Ni-Fe-AI-B Alloys
Authors: George E. P. , Liu C. T. , Sparks C. J. , Kao Ming-Yuan , Horton J. A. , Kunsmann Henry , King Todd 
Published: March 2011

AbstractConventionally cast and hot-rolled Ni-Fe-AI-B alloys containing 4-20 at.% Fe, 23.9- 31.5 at.% Al, and 300 wppm B were investigated in this study. After oil quenching from 1300°C, all the alloys—except SMA-15 (27A1-14Fe)—have at least a two-phase microstructure, one phase of which is martensite with the characteristic plate morphology, and the other a globular second phase distributed throughout the microstructure. The amount of second phase generally increases with increasing Fe content. Alloys containing less than 14% Fe were found to be quite brittle at room temperature, indicating that a ductile second phase is at least partly responsible for the improved room-temperature ductility in the high-Fe alloys. The best tensile ductility (12%) was obtained in SMA-17 (23.9AI-20Fe) which was shown by X-ray diffraction to consist of 40% (mostly disordered) fcc [(Ni,Fe)3 (AI,Fe)] + 30% (partly ordered) bct martensite + 30% B2. Differential scanning calorimetry showed that the transformation temperatures for this alloy were MP = 65°C and AP = 95°C. Room-temperature tensile strains of 2-3% could be almost completely recovered in SMA-17 by heating for 3 min. at 600°C with the load removed. Upon subsequent cycling (i.e., strain-anneal cycling), the amount of strain recovery increased dramatically from 70% in the first cycle to nearly 100% after 4-5 cycles, indicating that cold work may help in improving the shape memory characteristics of this alloy. SMA-15 was found to have significantly higher transformation temperatures (Mp = 143°C and Ap = 170°C) than SMA-17; however, it is relatively brittle compared to SMA-17.
Study of Transformation-Induced Ductility in Polycrystalline Nickel Aluminide
Authors: Murthy Ananda S. , Goo Edward 
Published: March 2011

AbstractNickel aluminide intermetallic compounds are of interest due to their good high temperature properties. However, they are associated with room temperature brittleness. A method for enhancing the room temperature ductility of polycrystalline NiAI in the composition range of 62-65 at.% by using the martensitic transformation is presented. Transformationinduced ductilities up to 4.5% in specimens with coarse grains have been obtained in our investigation. The effects of Ni concentration, grain size and quenching rate from the parent B2 phase are studied and optimized to induce maximum transformation ductility. The original excellent high temperatu re properties are restored from the ‘soft’ room temperatu re martensitic phase by heating to an appropriate temperature to revert to the equilibrium phases.
The Influence of the Microstructure of CU-ZN-AL Shape Memory Alloy on Mechanical Hysteresis
Authors: Buffard L. , Charbonnier P. , Roucau C. , Dubois B. 
Published: March 2011

AbstractCu-Zn-Al shape memory alloys may offer good thermomechanical properties for industrial applications. However, it is important to control transformation temperatures,the aging and the fatigue behaviour.We compare in this paper the effects of two thermomechanical treatments on industrial springs:“Direct” treatment consists in homogenization in β phase, annealing and training.“Inverse” treatment consists in homogenization in β phase, training and annealing.A correlation between electron microscopy observations and D.S.C. experiments shows that heterogeneous ordered state (β+y2+β3) in Cu25%wtZn9%wtAl is an essential parameter influencing mechanical hysteresis.
The Effect of Some Factors on Ms and Sme in Ce-TZP Ceramics
Authors: Jiang Bohong , Tu Jinbiao , Hsu T.Y. , Xu Zuyao , Qi Xuan , Zheng Xiuhua , Zhong Jiaxiang 
Published: March 2011

As known to all,shape memory behaviour has been observed in a variety of metallic alloys. This phenomenon, however, is not only observed in that field but also in other materials recently, such as in polymers,intermetallic compounds and ceramics, especially in zirconia ceramics.Swain [1] observed the shape recovery of a bent magnesia-partiallystabilized zirconia (Mg-PSZ) bar upon heating above a certain temperature. The maximum deflection which was nearly completely recovered on heating is about 300 μm.Chen et al [2] investigated the pseudoelasticity and shape memory effect (SME) in ceria-stabilized tetragonal zirconia polycrystals (Ce- TZP) containing 12 mol% CeO2.Wang et al [3] also observed the SME in Ce-TZP containing 10 mol% CeO2,.Here we would like to introduce some of results conducted recently in our group on SHE in Ce-TZP ceramics.
On the Electronic Nature of Phase Transformations in Ti-Me Shape Memory Compounds
Authors: Shabalovskaya S. A. 
Published: March 2011

AbstractBinary or quasi-binary compounds TI-Me (where Me stands for Fe, Co, Ni, Pd. Pt and Au, or Ni with one of the above metals) with the B2 (CsCl) structure are known to undergo martensitic transformations of two types: B2-B19'(B19) and B2-R, with an Intermediate precursor charge-density-wave Incommensurate phase IS. Analysis of both experimental and theoretical data enabled us to establish empirical relations between the transformation temperatures: Ms(B2-B19') and TIs(B2-1S), and fundamental parameters of both electronic and crystal structures of the compounds, such as the lattice parameters, the shift of the d-band in the compound with respect to that in the pure Me, the compound's d-band width, the Ti site-projected d-densities of states at the Fermi level In the compound and BCC Ti, and the temperature of β-β allotropic transformation In pure Ti. This correlation is based on localization of the Me d-bands in the compounds. As a result the Me-Me interaction becomes less important, and the interatomic interactions are controlled by d-d (Ti-Ti) and sp-d (Me-Ti) bonds. The Fermi levels are dominated by the Ti d-states, which control the lattice dynamics as well. The latter is also reflected in closeness of the C' moduli and similar values of the phonon frequencies In Ti and the TiNi compound. Since the intermediate IS phase results from a frozen phonon mode and Is controlled by the electron-phonon interaction, the B2-IS transition temperature can be correlated with the Debye Temperature, θD as: TIS=λθD. Estimates based on experimental data show that for Ti-Ni alloys λ < 1.3. A decrease of λ upon alloying with Fe stabilizes the B2 phase.
Effect of Vacancy Clustering on Stabilization of Martensite in Copper Based Shape Memory Alloys
Authors: Kong Yingjie , Jiang Bohong , Hsu T.Y. , Wang Baoyi , Wang Tianming 
Published: March 2011

AbstractVacancy behaviors during ageing of Cu-26Zn-4A1 and Cu-14Al-4Ni alloys have been investigated and compared by means of positron annihilation (PA) and electrical resistivity measurement. For ageing in martensitic state after direct quenching, it is observed that the S parameter values of Cu-Zn- Al specimens, measured in liquid nitrogen, increase at first and then decrease, while those of Cu-Al-Ni remain unchanged. The activation energies calculated from the S parameter for increasing and decreasing stages are o.4lev and o.63ev respectively, and the former can be corresponding to the formation energy of vacancy clustering, while the latter may be regarded as the migration energy of effective vacancies. A mechanism is put forward that the clustering of quenched-in vacancies results in a decreasing of the ordering degree and a reduction of the stored energy in martensite, which is responsible for the early stage of the stabilization of martensite in Cu-Zn-Al alloys. However, the fact that Cu-Al-Ni alloy is not subject to the stabilization is assumed to be owing to the immobility of supersaturated vacancies in its martensitic state which may be associated with the strong binding force between Ni and Al atoms.
MÖssbauer Study of a Tinife Shape Memory Alloy.
Authors: Jimenez M. , Marquina V. , Aburto S. , Marquina M.L. , Gomez R. , Rios-Jara D. 
Published: March 2011

AbstractMÖssbauer spectroscopy is very sensitive to structural transitions that may occur during a phase change of the type known to arise in the shape memory TiNiFe alloy. In this work we present the results of resistance vs temperature, differential scanning calorimetry (DSC) and Mössbauer spectroscopy (MS) measurements in Ti50Ni47Fe3 sample. The resistance vs temperature curve shows the usual sharp increase associated to the B2 → R transition at Tp = 245 K and then raises until a maximum is attained at ∼ 150 K. The DSC curve shows a peak maximum at the same temperature where the resistivity starts to increase. The room temperature Mössbauer spectrum consists of a single line, indicating that the iron atoms have cubic surroundings. As temperature is lowered, a small asymmetric quadrupole doublet begins to develop. The isomer shift (I.S.) and quadrupole splitting (ΔQ) values of this doublet increase with decreasing temperature until almost constant values are achieved at temperatures ∼ 100 K. We relate the changes in the Mössbauer spectra with previously proposed charge density wave induced premartensitic transition.
Thermodynamics, Phase Equilibria and Martensitic Transformation in Fe-Mn-Si Alloys
Authors: Forsberg Annika , Ågren John 
Published: March 2011

AbstractThe thermodynamic properties of the Fe-Mn-Si system are analyzed by means of thermodynamic models for the individual phases. Special attention is paid to γ → ε martensitic transition. A complete set of parameters, from which arbitrary sections of the phase diagram as well as the Ma and As temperatures may be calculated, has been obtained.
Fe-Mn-Si Based Shape Memory Alloys
Authors: Otsuka H. 
Published: March 2011

AbstractFe-Mn-Si based alloys are non-thermoelastic shape memory alloys which utilize the stress-induced transformation from γ austenite to ε martensite. After these shape memory alloys are deformed at room temperature, they recover their original shape when heated to 473K or higher. Fe-Mn-Si based alloys contain 15% to 33% Mn, 5% to 6% Si, 0% to 13% Cr, and 0% to 10% Ni in weight. Mn and Si are indispensable for the development of shape memory effect (SME). The amounts of these elements require to be adjusted so that the Neel temperature (TN) lies lower than Ms temperature and the Ms lies just below room temperature. Though the volume of stress-induced martensite is only 20 to 30%, a thermomechanical treatment called “training” has made it possible for the alloy to recover from a tensi le deformation exceeding 3%. Today, the use of the shape memory al loys for steel pipe joints is being studied. They have already been put into practical use for an auxiliary bicycle part to clamp the frame.
Electron Microscopy of Stress-Induced Martensite and Pretransition Microstructures in Ni62.5Al37.5
Authors: Schryvers D. , Tanner L.E. 
Published: March 2011

AbstractStatic configurations of stress-induced martensite and pretransition microstructures in Ni62.5A137.5 have been studied with conventional as well as high resolution electron microscopy using single crystal TEM specimens containing defect sites of extremely high stress intensity. From images of different regions around such defects it can be concluded that the austenite lattice develops transverse displacement modulations with increasing amplitude and correlation directly related to the {110}<110> shear-plus-shuffle displacements required to form the martensite structures. Different steps in this transition sequence are presented and discussed.
Thermal Hysteresis in Ni-Ti and Ni-Ti-X Alloys and Their Applications
Authors: Suzuki Yuichi , Horikawa Hiroshi 
Published: March 2011

AbstractThe first practical shape memory alloy, NITINOL, has a transformation thermal hysteresis(Hs) of about 30K and a monoclinic martensite structure. The first application of this alloy was a pipe coupling. Although various ideas were proposed on thermal actuators, they were not easily industrialized at least partly because the amount of Hs of the binary Ni-Ti alloy was too large. While the reduction of Hs is not so easy as transformation temperature control, the alloy was improved in terms of Hs through the discovery of new martensite phases. The first Hs reduction was realized in a Ni-Ti-Cu alloy. The copper addition changes the martensite structure to orthorhombic and reduces Hs to 10-15K. The alloy was first applied to a thermal actuator in automobile fog-lamps. Subsequently the R-phase transformation was identified in the binary alloy under the combination of cold working and a heat treatment at relatively low temperatures. Hs was further reduced to 2K in the R-phase transformation. The R-phase transformation is also featured by an excellent fatigue life which reaches one million cycles. The small Hs and long repetition life rapidly widened the application field of shape memory actuators. An expansion of Hs up to 100K was also achieved by a combination of fine dispersion of niobium and cold working. At present, the Hs of the Ni-Ti base alloys ranges from 2K to 100K. An appropriate alloy system can be selected according to applications. The binary alloy has found a wider application field in the super elastic application. In this paper, we summarize the progress in the modification of Hs and present recent applications of each transformation.
Cycling Times of Thin-Film NiTi on Si
Authors: Jardine A. Peter 
Published: March 2011

AbstractThe thermo-mechanical properties of NiTi are well known for bulk material although its deposition and utilization as a thin film are still in their earliest stages. The deposition of thin-films of Shape Memory Effect NiTi onto Si(100) wafers offers several advantages over bulk NiTi, including fast response times and comparitively large transformation forces, and so is a promising candidate as a micro-actuator for MicroElectroMechanical (MEMS) systems as well as in strain measurements. The response time for a variety of NiTi layers were modelled under different boundary conditions and show response times similar to the acoustic velocities for one micron thick NiTi.
Shear-Enhanced Structure and Dynamics in Semidilute Polymer Solutions
Authors: Dixon P. K. , Pine D. J. , Wu X.-L. 
Published: March 2011

AbstractWe present elastic light scattering measurements of a semidilute polymer solution under shear flow. The basic symmetries observed in the shear-enhanced structure factor agree with the predictions of recently proposed theoretical models. The enhancement appears to be due to a coupling between the polymer concentration and shear flow through the concentration-dependent viscosity and normal stress coefficients. We also found an unexpected long wavelength peak in the shear-enhanced structure factor. Transient scattering measurements upon the cessation of shear have revealed the origin of this peak. The polymer solution demonstrates two modes of relaxation for concentration fluctuations in equilibrium due to a coupling between collective diffusion and stress relaxation. The transient scattering measurements indicate that the mechanism that couples the concentration fluctuations to the shear flow, and thereby enhances concentration fluctuations, selectively enhances only the slower of the two equilibrium modes. This selective enhancement generates the long wavelength peak in the shear-enhanced structure.
Rheo-Optics of an Augned Thermotropic Liquid Crystalline Polymer
Authors: Srinivasarao Mohan , Garay Raul O. , Winter H. Henning , Stein Richard S. 
Published: March 2011

AbstractRheo-optical studies on aligned and unaligned melts of a main chain thermotropic polyester with flexible spacers are discussed in terms of the predictions of the Ericksen-Leslie equations. It is shown, using conoscopy, that the director is flowaligning at temperatures close to TNI and nonflow-aligning close to a smectic to nematic (TSN) phase transition. The implications of these results are discussed in terms of the change in sign of one of the Leslie viscosity coefficients and interpreted in the framework of the Ericksen-Leslie Theory.
Phase Diagram of a Lattice Model for Ternary Mixtures of Water, Oil, and Surfactants
Authors: Laradji Mohamed , Guo Hong , Grant Martin , Zuchkermann Martin J. 
Published: March 2011

AbstractLarge scale Monte-Carlo simulations have been performed on a lattice model for a three component system of water, oil, and surfactants to obtain the phase equilibria and scattering behavior for a wide range of temperatures and chemical potentials. We observed that this model has a rich phase behavior, namely a water-oil phase coexistence, a microemulsion phase, a lamellar phase, and a square phase. This phase diagram is consistent with experiments, and is in qualitative agreement with a model of Gompper and Schick [ Phys. Rev. Lett. 62, 1647 (1989)].
Virial Expansions for Low Dimensional Ferrofluids
Authors: Widom M. , Zhang H. 
Published: March 2011

AbstractFerrofluids are colloidal suspensions of magnetic particles which we model as a dilute gas of dipolar hard spheres. At low particle density the osmotic pressure and magnetic susceptibility may be expanded in a virial series. We evaluate the second virial coefficients for fluids confined to a line, or to a plane, as well as ordinary three dimensional fluids in ellipsoidal containers. We focus our attention on anisotropy of the magnetic susceptibility and point out the role of particle chaining in determining the magnetic anisotropy of low dimensional ferrofluids.
Instabolotoes of a Ferrofludd Droplet in Alternatong and Rotatong Maghietic Fields
Authors: Bacrl J.-C. , PerZynski R. , Salin D. , Čebers A. O. 
Published: March 2011

AbstractFor the first time, response of magnetic fluid microdrops to time dependent magnetic fields are tested in two different experimental conditions (rotating field, crossed static and alternating fields). In both cases, a new shape instability is observed leading to cog-wheels either rotating either motionless. A simple model account for the stability range of oblate ellipsoidal shapes and for the lateral peak instability leading to the cogs which crown the cog-wheel.
Sheared Suspensions I - Electrorheology and Depletion Aggregation
Authors: Melrose J. R. 
Published: March 2011

AbstractIdealised models of sheared suspensions are studied by computer simulation. In this and the companion paper [1], non-equilibrium phase diagrams are evaluated for two models: one for electrorheology (this paper), the other for aggregation due to depletion (companion paper [1]). Distinct structural phases and their associated rheology are reported.
Flocculation and Coalescence of Oil-in-Warer Emulsions
Authors: Bibette J. 
Published: March 2011

AbstractEmulsions are commonly made of macrosized droplets dispersed in a continuous solvent. These systems are subject to two types of instabilities. One is reversible: flocculation, the other is irreversible: coalescence. The reversible flocculation induced by excess surfactant is studied. It is shown that an attractive interaction arises from depletion of surfactant micelles and leads to a fluid-solid phase transition. The sensitivity of this phase transition to the oil droplet diameter leads to a fractionated crystallisation method for purifying in size highly polydisperse emulsions. These well characterized systems are used to study the stability of the film against coalescence. Two distinct regimes of coalesence are found. One is driven by the surfactant chemical potential and occurs in a dilute emulsion. The other is driven by the water chemical potential and takes place in a concentrated emulsion which ressembles a biliquid foam.
Brillouin Scattering from Gels
Authors: Mallamace F. , Micali N. , Vasi C. , Sciortino F. , Bansil R. , Pajevic S. 
Published: March 2011

AbstractWe have investigated the question of heterogeneity in gels using Brillouin scattering, depolarized Rayleigh scattering and dynamic light scattering measurements on methylmethacrylate (MMA) gels crosslinked with varying amount of ethylene-dimethacrylate (EDMA). We find that the k dependence of the phase velocity changes on increasing the cross-link content. For higher concentrations of crosslink we observe maxima and minima in the k dependence of the phase velocity which e associate with spatial inhomogeneities in the gel, with the formation of regions of low and high cross-link density, respectively. This micro-phase separation occurs around crosslink content of 3-4 %. At this same concentration depolarized Rayleigh measurements show a marked decrease in the number of MMA side groups capable of rotating.