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Sample records for nanoscale physical properties

  1. Probing physical properties at the nanoscale using atomic force microscopy

    NASA Astrophysics Data System (ADS)

    Ditzler, Lindsay Rachel

    Techniques that measure physical properties at the nanoscale with high sensitivity are significantly limited considering the number of new nanomaterials being developed. The development of atomic force microscopy (AFM) has lead to significant advancements in the ability to characterize physical properties of materials in all areas of science: chemistry, physics, engineering, and biology have made great scientific strides do to the versatility of the AFM. AFM is used for quantification of many physical properties such as morphology, electrical, mechanical, magnetic, electrochemical, binding interactions, and protein folding. This work examines the electrical and mechanical properties of materials applicable to the field of nano-electronics. As electronic devices are miniaturized the demand for materials with unique electrical properties, which can be developed and exploited, has increased. For example, discussed in this work, a derivative of tetrathiafulvalene, which exhibits a unique loss of conductivity upon compression of the self-assembled monolayer could be developed into a molecular switch. This work also compares tunable organic (tetraphenylethylene tetracarboxylic acid and bis(pyridine)s assemblies) and metal-organic (Silver-stilbizole coordination compounds) crystals which show high electrical conductivity. The electrical properties of these materials vary depending on their composition allowing for the development of compositionally tunable functional materials. Additional work was done to investigate the effects of molecular environment on redox active 11-ferroceneyl-1 undecanethiol (Fc) molecules. The redox process of mixed monolayers of Fc and decanethiol was measured using conductive probe atomic force microscopy and force spectroscopy. As the concentration of Fc increased large, variations in the force were observed. Using these variations the number of oxidized molecules in the monolayer was determined. AFM is additionally capable of investigating

  2. Nanoscale chemical interaction enhances the physical properties of bioglass composites.

    PubMed

    Ravarian, Roya; Zhong, Xia; Barbeck, Mike; Ghanaati, Shahram; Kirkpatrick, Charles James; Murphy, Ciara M; Schindeler, Aaron; Chrzanowski, Wojciech; Dehghani, Fariba

    2013-10-22

    Bioglasses are favorable biomaterials for bone tissue engineering; however, their applications are limited due to their brittleness. In addition, the early failure in the interface is a common problem of composites of bioglass and a polymer with high mechanical strength. This effect is due to the phase separation, nonhomogeneous mixture, nonuniform mechanical strength, and different degradation properties of two compounds. To address these issues, in this study a nanoscale interaction between poly(methyl methacrylate) (PMMA) and bioactive glass was formed via silane coupling agent (3-trimethoxysilyl)propyl methacrylate (MPMA). A monolith was produced at optimum composition from this hybrid by the sol-gel method at 50 °C with a rapid gelation time (<50 min) that possessed superior physicochemical properties compared to pure bioglass and physical mixture. For instance, the Young's modulus of bioglass was decreased 40-fold and the dissolution rate of silica was retarded 1.5-fold by integration of PMMA. Prolonged dissolution of silica fosters bone integration due to the continuous dissolution of bioactive silica. The primary osteoblast cells were well anchored and cell migration was observed on the surface of the hybrid. The in vivo studies in mice demonstrated that the integrity of the hybrids was maintained in subcutaneous implantation. They induced mainly a mononuclear phagocytic tissue reaction with a low level of inflammation, while bioglass provoked a tissue reaction with TRAP-positive multinucleated giant cells. These results demonstrated that the presence of a nanoscale interaction between bioglass and PMMA affects the properties of bioglass and broadens its potential applications for bone replacement. PMID:24001050

  3. Influence of strain on the physical properties of materials at the nanoscale

    NASA Astrophysics Data System (ADS)

    Manoharan, Mohan Prasad

    At the nanoscale, materials properties differ substantially from that at the bulk scale, opening new avenues for technological applications and basic science research. Such size effects arise from dimensional and microstructural constraints, especially when specimen size coincides with the critical fundamental length scales for various physical properties. While the state of the art practice is to investigate the size effects on 'individual' properties (mechanical or electrical or thermal and so on), the focus of this research is to explore the size effects on the 'coupling' among these domains. In particular, the effect of mechanical strain on various physical properties of materials at the nanoscale is studied. This is motivated by the hypothesis that very small elastic strain could be engineered in micro and nanoscale systems to 'tune' materials properties, which is not possible at the bulk scale using strain as a parameter. The objective of this research is to study the influence of strain on various material properties at the nanoscale, such as crystal structure, thermal and electrical conductivity, electronic bandgap and tribological properties through experimental characterization. While characterization of nanoscale materials in single domains remains the state of the art, coupled domain studies usher even stiffer challenges. This is because in addition to the difficulties in nanoscale specimen preparation, handling and properties measurement, meticulous attention has to be given to the boundary conditions for each of the domains. Another desired feature of the experimental setup is the capability for in situ high resolution microscopy so that microstructural details as well as experimental accuracy are achieved. A major contribution of this research is the development of microfabricated integrated systems to perform coupled domain characterization of small scale specimens in situ in thermal (infra-red), micro-Raman and electron microscopes. In addition

  4. Nanoscale physical properties of polymer glasses formed by solvent-assisted laser deposition

    NASA Astrophysics Data System (ADS)

    Shepard, Kimberly; Arnold, Craig; Priestley, Rodney

    2015-03-01

    High-energy, low-density nanostructured polymer glasses are formed via the solvent-assisted laser deposition technique MAPLE (Matrix Assisted Pulsed Laser Evaporation). During film deposition, micro- to nano-size polymer/solvent clusters are ejected via laser ablation from a frozen dilute polymer solution. During flight to the substrate under vacuum, the clusters experience rapid cooling and solvent stripping, forming polymer nanoglobules. Bulk polymer films are formed via the gradual assembly of these spherical-like nanostructured building blocks (i.e. nanoglobules). The MAPLE process thus enables investigation of the exceptional properties of glasses formed under extreme processing conditions. In the bulk state, we probe the effect of process parameters and chemical identity of the thermal behavior of a series of methacrylate polymers. We also employ multiple techniques to directly measure the properties of the polymer nanoglobules and connect the results to the global film properties. This talk will address nanoscale dilatometry via AFM, in which the volume of an individual polymer nanoglobule is tracked as it is heated through its glass transition, as well as Flash DSC analysis of the thermal properties of nanogram size MAPLE-deposited polymer glasses. We then discuss these findings in the context of the material's unconventional route to the glassy state.

  5. Improving fundamental abilities of atomic force microscopy for investigating quantitative nanoscale physical properties of complex biological systems

    NASA Astrophysics Data System (ADS)

    Cartagena-Rivera, Alexander X.

    Measurements of local material properties of complex biological systems (e.g. live cells and viruses) in their respective physiological conditions are extremely important in the fields of biophysics, nanotechnology, material science, and nanomedicine. Yet, little is known about the structure-function-property relationship of live cells and viruses. In the case of live cells, the measurements of progressive variations in viscoelastic properties in vitro can provide insight to the mechanistic processes underpinning morphogenesis, mechano-transduction, motility, metastasis, and many more fundamental cellular processes. In the case of living viruses, the relationship between capsid structural framework and the role of the DNA molecule interaction within viruses influencing their stiffness, damping and electrostatic properties can shed light in virological processes like protein subunits assembly/dissassembly, maturation, and infection. The study of mechanics of live cells and viruses has been limited in part due to the lack of technology capable of acquiring high-resolution (nanoscale, subcellular) images of its heterogeneous material properties which vary widely depending on origin and physical interaction. The capabilities of the atomic force microscope (AFM) for measuring forces and topography with sub-nm precision have greatly contributed to research related to biophysics and biomechanics during the past two decades. AFM based biomechanical studies have the unique advantage of resolving/mapping spatially the local material properties over living cells and viruses. However, conventional AFM techniques such as force-volume and quasi-static force-distance curves are too low resolution and low speed to resolve interesting biophysical processes such as cytoskeletal dynamics for cells or assembly/dissasembly of viruses. To overcome this bottleneck, a novel atomic force microscopy mode is developed, that leads to sub-10-nm resolution and sub-15-minutes mapping of local

  6. Studying Physical Properties at the Nano-Scale: Thin Films, Nano-Particles and Molecules

    NASA Astrophysics Data System (ADS)

    Eisenstein, Alon

    Nanomaterials have been shown to be useful for many applications. The characterization of nanomaterials is a crucial step in understanding how to control their performance to tailor their properties for desired applications. In this thesis, several nanomaterials were studied using various methods, in an effort to characterize their properties. In the first chapter, the initial growth steps of nanometer thick polyelectrolyte film, grown layer-by-layer, were studied using Kelvin Probe Force Microscopy. The initially small domains grew with each added layer. Surface potential contrast enabled the visualization of these domains far beyond the point where no topographical variation was visible. In the second and third chapters, the potential of using collapsed-polymer nanoparticles as a carrier platform for active chemicals was studied using dye molecules as probes. Two methods were implemented, spectroscopy and isothermal titration calorimetry. Following the measurements, a binding model was proposed, which also provided thermodynamic quantification of the binding process. In the fourth chapter, an atomic force microscope probe holder was custom designed and built to enable characterization of the probes using scanning electron microscopy in an effort to facilitate specific identification of composite collapsed-polymer nanoparticles using tip-enhanced Raman Spectroscopy. In the fifth chapter, an ultra high vacuum gas dosing attachment was custom designed and built to enable a study of self-assembly of organic molecules on silicon surface. Pulse dosing was found to affect the self-assembled pattern on the surface. In the final chapter, the surface halogenation of copper surfaces was studied using a scanning tunneling microscope. The reaction was induced by an electron pulse. The scattered halogens, dissociated from the initial molecule, provided information regarding the reaction dynamics of the process.

  7. Physical vapor deposited titanium thin films for biomedical applications: Reproducibility of nanoscale surface roughness and microbial adhesion properties

    NASA Astrophysics Data System (ADS)

    Lüdecke, Claudia; Bossert, Jörg; Roth, Martin; Jandt, Klaus D.

    2013-09-01

    The surface topography is of great importance for the biological performance of titanium based implants since it may influence the initial adsorption of proteins, cell response, as well as microbial adhesion. A recently described technique for the preparation of titanium thin films with an adjustable surface roughness on the nanometer scale is the physical vapor deposition (PVD). The aims of this study were to statistically evaluate the reproducibility of nanorough titanium thin films prepared by PVD using an atomic force microscopy (AFM) based approach, to test the microbial adhesion in dependence of the nanoscale surface roughness and to critically discuss the parameters used for the characterization of the titanium surfaces with respect to AFM microscope settings. No statistically significant differences were found between the surface nanoroughnesses of the PVD prepared titanium thin films. With increasing surface nanoroughness, the coverage by Escherichia coli decreased and the microbial cells were increasingly patchy distributed. The calculated roughness values significantly increased with increasing AFM scan size, while image resolution and pixel density had no influence on this effect. Our study shows that PVD is a suitable tool to reproducibly prepare titanium thin films with a well-defined surface topography on the nanometer scale. These surfaces are, thus, a suitable 2D model system for studies addressing the interaction between surface nanoroughness and the biological system. First results show that surface roughness even on the very low nanometer scale has an influence on bacterial adhesion behavior. These findings give new momentum to biomaterials research and will support the development of biomaterials surfaces with anti-infectious surface properties.

  8. Using Plasmon Peaks in Electron Energy-Loss Spectroscopy to Determine the Physical and Mechanical Properties of Nanoscale Materials

    SciTech Connect

    Howe, James M.

    2013-05-09

    In this program, we developed new theoretical and experimental insights into understanding the relationships among fundamental universality and scaling phenomena, the solid-state physical and mechanical properties of materials, and the volume plasmon energy as measured by electron energy-loss spectroscopy (EELS). Particular achievements in these areas are summarized as follows: (i) Using a previously proposed physical model based on the universal binding-energy relation (UBER), we established close phenomenological connections regarding the influence of the valence electrons in materials on the longitudinal plasma oscillations (plasmons) and various solid-state properties such as the optical constants (including absorption and dispersion), elastic constants, cohesive energy, etc. (ii) We found that carbon materials, e.g., diamond, graphite, diamond-like carbons, hydrogenated and amorphous carbon films, exhibit strong correlations in density vs. Ep (or maximum of the volume plasmon peak) and density vs. hardness, both from available experimental data and ab initio DFT calculations. This allowed us to derive a three-dimensional relationship between hardness and the plasmon energy, that can be used to determine experimentally both hardness and density of carbon materials based on measurements of the plasmon peak position. (iii) As major experimental accomplishments, we demonstrated the possibility of in-situ monitoring of changes in the physical properties of materials with conditions, e.g., temperature, and we also applied a new plasmon ratio-imaging technique to map multiple physical properties of materials, such as the elastic moduli, cohesive energy and bonding electron density, with a sub-nanometer lateral resolution. This presents new capability for understanding material behavior. (iv) Lastly, we demonstrated a new physical phenomenon - electron-beam trapping, or electron tweezers - of a solid metal nanoparticle inside a liquid metal. This phenomenon is

  9. Synthesis and properties of nanoscale titanium boride

    NASA Astrophysics Data System (ADS)

    Efimova, K. A.; Galevskiy, G. V.; Rudneva, V. V.

    2015-09-01

    This work reports the scientific and technological grounds for plasma synthesis of titanium diboride, including thermodynamic and kinetic conditions of boride formation when titanium and titanium dioxide are interacting with products resulting from boron gasification in the nitrogen - hydrogen plasma flow, and two variations of its behavior using the powder mixtures: titanium - boron and titanium dioxide - boron. To study these technology variations, the mathematical models were derived, describing the relation between element contents in the synthesized products of titanium and free boron and basic parameters. The probable mechanism proposed for forming titanium diboride according to a "vapour - melt - crystal" pattern was examined, covering condensation of titanium vapour in the form of aerosol, boriding of nanoscale melt droplets by boron hydrides and crystallization of titanium - boron melt. The comprehensive physical - chemical certification of titanium diboride was carried out, including the study of its crystal structure, phase and chemical composition, dispersion, morphology and particle oxidation. Technological application prospects for use of titanium diboride nanoscale powder as constituent element in the wettable coating for carbon cathodes having excellent physical and mechanical performance and protective properties.

  10. Properties of nanoscale metal hydrides.

    PubMed

    Fichtner, Maximilian

    2009-05-20

    Nanoscale hydride particles may exhibit chemical stabilities which differ from those of a macroscopic system. The stabilities are mainly influenced by a surface energy term which contains size-dependent values of the surface tension, the molar volume and an additional term which takes into account a potential reduction of the excess surface energy. Thus, the equilibrium of a nanoparticular hydride system may be shifted to the hydrogenated or to the dehydrogenated side, depending on the size and on the prefix of the surface energy term of the hydrogenated and dehydrogenated material. Additional complexity appears when solid-state reactions of complex hydrides are considered and phase segregation has to be taken into account. In such a case the reversibility of complex hydrides may be reduced if the nanoparticles are free standing on a surface. However, it may be enhanced if the system is enclosed by a nanoscale void which prevents the reaction partners on the dehydrogenated side from diffusing away from each other. Moreover, the generally enhanced diffusivity in nanocrystalline systems may lower the kinetic barriers for the material's transformation and, thus, facilitate hydrogen absorption and desorption. PMID:19420657

  11. Nanoscale theranostics for physical stimulus-responsive cancer therapies.

    PubMed

    Chen, Qian; Ke, Hengte; Dai, Zhifei; Liu, Zhuang

    2015-12-01

    Physical stimulus-responsive therapies often employing multifunctional theranostic agents responsive to external physical stimuli such as light, magnetic field, ultra-sound, radiofrequency, X-ray, etc., have been widely explored as novel cancer therapy strategies, showing encouraging results in many pre-clinical animal experiments. Unlike conventional cancer chemotherapy which often accompanies with severe toxic side effects, physical stimulus-responsive agents usually are non-toxic by themselves and would destruct cancer cells only under specific external stimuli, and thus could offer greatly reduced toxicity and enhanced treatment specificity. In addition, physical stimulus-responsive therapies can also be combined with other traditional therapeutics to achieve synergistic anti-tumor effects via a variety of mechanisms. In this review, we will summarize the latest progress in the development of physical stimulus-responsive therapies, and discuss the important roles of nanoscale theranostic agents involved in those non-conventional therapeutic strategies. PMID:26410788

  12. Role of Au in the growth and nanoscale optical properties of ZnO nanowires

    SciTech Connect

    Brewster, M.; Zhou, Xiang; Lim, S. K.; Gradecak, S.

    2011-03-17

    Metallic nanoparticles play a crucial role in nanowire growth and have profound consequences on nanowire morphology and their physical properties. Here, we investigate the evolving role of the Au nanoparticle during ZnO nanowire growth and its effects on nanoscale photoemission of the nanowires. We observe the transition from Au-assisted to non-assisted growth mechanisms during a single nanowire growth, with significant changes in growth rates during these two regimes. This transition occurs through the reduction of oxygen partial pressure, which modifies the ZnO facet stability and increases Au diffusion. Nanoscale quenching of ZnO cathodoluminescence occurs near the Au nanoparticle due to excited electron diffusion to the nanoparticle. Thus, the Au nanoparticle is critically linked to the nanowire growth mechanism and corresponding growth rate through the energy of its interface with the ZnO nanowire, and its presence modifies nanowire optical properties on the nanoscale.

  13. Physical principles of genomic regulation through cellular nanoscale structure and implications for initiation of carcinogenesis

    NASA Astrophysics Data System (ADS)

    Backman, Vadim

    2011-03-01

    Although compelling evidence suggests that cellular nanoarchitecture and nanoscale environment where molecular interactions take place would be expected to significantly affect macromolecular processes, biological ramifications of cellular nanoscale organization have been largely unexplored. This understanding has been hampered in part by the diffraction limited resolution of optical microscopy. The talk will discuss a novel optical microscopy technique, partial wave spectroscopic (PWS) microscopy, that is capable of quantifying statistical properties of cell structure at the nanoscale. Animal and human studies demonstrated that an alteration in the statistical properties of the nanoscale mass density distribution in the cell nucleus (e.g. nuclear nanoarchitecture) is one of the earliest and ubiquitous events in carcinogenesis and precedes any other known morphological changes at larger length scales (e.g. microarchitecture). The talk will also discuss the physical principles of how the alteration in nuclear nanoarchitecture may modulate genomic processes and, in particular, gene transcription. Work done in collaboration with Hariharan Subramanian, Prabhakar Pradhan, Dhwanil Damania, Lusik Cherkezyan, Yolanda Stypula, Jun Soo Kim, Igal Szleifer, Northwestern University, Evanston, IL, Hemant K. Roy, Northshore University HealthSystems, Evanston, IL

  14. Using theory and computation to model nanoscale properties

    PubMed Central

    Schatz, George C.

    2007-01-01

    This article provides an overview of the use of theory and computation to describe the structural, thermodynamic, mechanical, and optical properties of nanoscale materials. Nanoscience provides important opportunities for theory and computation to lead in the discovery process because the experimental tools often provide an incomplete picture of the structure and/or function of nanomaterials, and theory can often fill in missing features crucial to understanding what is being measured. However, there are important challenges to using theory as well, as the systems of interest are usually too large, and the time scales too long, for a purely atomistic level theory to be useful. At the same time, continuum theories that are appropriate for describing larger-scale (micrometer) phenomena are often not accurate for describing the nanoscale. Despite these challenges, there has been important progress in a number of areas, and there are exciting opportunities that we can look forward to as the capabilities of computational facilities continue to expand. Some specific applications that are discussed in this paper include: self-assembly of supramolecular structures, the thermal properties of nanoscale molecular systems (DNA melting and nanoscale water meniscus formation), the mechanical properties of carbon nanotubes and diamond crystals, and the optical properties of silver and gold nanoparticles. PMID:17438274

  15. Nitrogen-vacancy centers in diamond: nanoscale sensors for physics and biology.

    PubMed

    Schirhagl, Romana; Chang, Kevin; Loretz, Michael; Degen, Christian L

    2014-01-01

    Crystal defects in diamond have emerged as unique objects for a variety of applications, both because they are very stable and because they have interesting optical properties. Embedded in nanocrystals, they can serve, for example, as robust single-photon sources or as fluorescent biomarkers of unlimited photostability and low cytotoxicity. The most fascinating aspect, however, is the ability of some crystal defects, most prominently the nitrogen-vacancy (NV) center, to locally detect and measure a number of physical quantities, such as magnetic and electric fields. This metrology capacity is based on the quantum mechanical interactions of the defect's spin state. In this review, we introduce the new and rapidly evolving field of nanoscale sensing based on single NV centers in diamond. We give a concise overview of the basic properties of diamond, from synthesis to electronic and magnetic properties of embedded NV centers. We describe in detail how single NV centers can be harnessed for nanoscale sensing, including the physical quantities that may be detected, expected sensitivities, and the most common measurement protocols. We conclude by highlighting a number of the diverse and exciting applications that may be enabled by these novel sensors, ranging from measurements of ion concentrations and membrane potentials to nanoscale thermometry and single-spin nuclear magnetic resonance. PMID:24274702

  16. EDITORIAL: Physical behaviour at the nanoscale: a model for fertile research Physical behaviour at the nanoscale: a model for fertile research

    NASA Astrophysics Data System (ADS)

    Demming, Anna

    2013-06-01

    At the nanoscale physics follows familiar principles that lead to unfamiliar and even unlikely responses. The change in the balance of a range of physical features results in behaviour that can differ wildly from the same materials at the macroscale. In this issue Di Ventra and Pershin examine some of the memory effects that have attracted increasing interest in investigations of nanoscale electronic systems [1]. The work builds on the familiar premise that external perturbations cannot have an instantaneous effect on any condensed matter system. As they point out, 'This is even more so in systems of nanoscale dimensions where the dynamics of a few atoms may affect the whole structure dramatically'. In this way they explain that the response of these systems will always have some degree of memory present and that memristive, memcapacitive and meminductive systems are simply examples where this feature is particularly prominent. In the late 1990s investigations into the use of carbon nanotubes and SiC nanorods revealed that the moduli of these structures changes with diameter, highlighting the eccentricities of mechanical properties at the nanoscale. These results prompted Miller at the University of Saskatchewan and Shenoy at the Indian Institute of Technology to study the properties of nanotubes and nanorods in detail [2]. 'In the eyes of an engineer these structures are essentially little beams', they explained, 'Albeit they are "little" to a degree that challenges our traditional notions of continuum mechanics'. In their work they developed one of the first simple models for explaining the behaviour of the Young's modulus of nanostructures, verified by direct atomistic simulation of axial loading of these structures. Since then, consideration of different nanoscale structures and the dissipation of energy under stress and strain have also demystified the extraordinary mechanical properties of natural materials such as collagen [3] and spider's silk [4]. The

  17. Nanoscale electrical properties of epitaxial Cu3Ge film

    PubMed Central

    Wu, Fan; Cai, Wei; Gao, Jia; Loo, Yueh-Lin; Yao, Nan

    2016-01-01

    Cu3Ge has been pursued as next-generation interconnection/contact material due to its high thermal stability, low bulk resistivity and diffusion barrier property. Improvements in electrical performance and structure of Cu3Ge have attracted great attention in the past decades. Despite the remarkable progress in Cu3Ge fabrication on various substrates by different deposition methods, polycrystalline films with excess Ge were frequently obtained. Moreover, the characterization of nanoscale electrical properties remains challenging. Here we show the fabrication of epitaxial Cu3Ge thin film and its nanoscale electrical properties, which are directly correlated with localized film microstructures and supported by HRTEM observations. The average resistivity and work function of epitaxial Cu3Ge thin film are measured to be 6 ± 1 μΩ cm and ~4.47 ± 0.02 eV respectively, qualifying it as a good alternative to Cu. PMID:27363582

  18. Nanoscale electrical properties of epitaxial Cu3Ge film

    NASA Astrophysics Data System (ADS)

    Wu, Fan; Cai, Wei; Gao, Jia; Loo, Yueh-Lin; Yao, Nan

    2016-07-01

    Cu3Ge has been pursued as next-generation interconnection/contact material due to its high thermal stability, low bulk resistivity and diffusion barrier property. Improvements in electrical performance and structure of Cu3Ge have attracted great attention in the past decades. Despite the remarkable progress in Cu3Ge fabrication on various substrates by different deposition methods, polycrystalline films with excess Ge were frequently obtained. Moreover, the characterization of nanoscale electrical properties remains challenging. Here we show the fabrication of epitaxial Cu3Ge thin film and its nanoscale electrical properties, which are directly correlated with localized film microstructures and supported by HRTEM observations. The average resistivity and work function of epitaxial Cu3Ge thin film are measured to be 6 ± 1 μΩ cm and ~4.47 ± 0.02 eV respectively, qualifying it as a good alternative to Cu.

  19. Nanoscale electrical properties of epitaxial Cu3Ge film.

    PubMed

    Wu, Fan; Cai, Wei; Gao, Jia; Loo, Yueh-Lin; Yao, Nan

    2016-01-01

    Cu3Ge has been pursued as next-generation interconnection/contact material due to its high thermal stability, low bulk resistivity and diffusion barrier property. Improvements in electrical performance and structure of Cu3Ge have attracted great attention in the past decades. Despite the remarkable progress in Cu3Ge fabrication on various substrates by different deposition methods, polycrystalline films with excess Ge were frequently obtained. Moreover, the characterization of nanoscale electrical properties remains challenging. Here we show the fabrication of epitaxial Cu3Ge thin film and its nanoscale electrical properties, which are directly correlated with localized film microstructures and supported by HRTEM observations. The average resistivity and work function of epitaxial Cu3Ge thin film are measured to be 6 ± 1 μΩ cm and ~4.47 ± 0.02 eV respectively, qualifying it as a good alternative to Cu. PMID:27363582

  20. Physical controls on directed virus assembly at nanoscale chemical templates

    SciTech Connect

    Cheung, C L; Chung, S; Chatterji, A; Lin, T; Johnson, J E; Hok, S; Perkins, J; De Yoreo, J

    2006-05-10

    Viruses are attractive building blocks for nanoscale heterostructures, but little is understood about the physical principles governing their directed assembly. In-situ force microscopy was used to investigate organization of Cowpea Mosaic Virus engineered to bind specifically and reversibly at nanoscale chemical templates with sub-30nm features. Morphological evolution and assembly kinetics were measured as virus flux and inter-viral potential were varied. The resulting morphologies were similar to those of atomic-scale epitaxial systems, but the underlying thermodynamics was analogous to that of colloidal systems in confined geometries. The 1D templates biased the location of initial cluster formation, introduced asymmetric sticking probabilities, and drove 1D and 2D condensation at subcritical volume fractions. The growth kinetics followed a t{sup 1/2} law controlled by the slow diffusion of viruses. The lateral expansion of virus clusters that initially form on the 1D templates following introduction of polyethylene glycol (PEG) into the solution suggests a significant role for weak interaction.

  1. Atomistic methodologies for material properties of 2D materials at the nanoscale

    NASA Astrophysics Data System (ADS)

    Zhang, Zhen

    Research on two dimensional (2D) materials, such as graphene and MoS2, now involves thousands of researchers worldwide cutting across physics, chemistry, engineering and biology. Due to the extraordinary properties of 2D materials, research extends from fundamental science to novel applications of 2D materials. From an engineering point of view, understanding the material properties of 2D materials under various conditions is crucial for tailoring the electrical and mechanical properties of 2D-material-based devices at the nanoscale. Even at the nanoscale, molecular systems typically consist of a vast number of atoms. Molecular dynamics (MD) simulations enable us to understand the properties of assemblies of molecules in terms of their structure and the microscopic interactions between them. From a continuum approach, mechanical properties and thermal properties, such as strain, stress, and heat capacity, are well defined and experimentally measurable. In MD simulations, material systems are considered to be discrete, and only interatomic potential, interatomic forces, and atom positions are directly obtainable. Besides, most of the fracture mechanics concepts, such as stress intensity factors, are not applicable since there is no singularity in MD simulations. However, energy release rate still remains to be a feasible and crucial physical quantity to characterize the fracture mechanical property of materials at the nanoscale. Therefore, equivalent definition of a physical quantity both in atomic scale and macroscopic scale is necessary in order to understand molecular and continuum scale phenomena concurrently. This work introduces atomistic simulation methodologies, based on interatomic potential and interatomic forces, as a tool to unveil the mechanical properties, thermal properties and fracture mechanical properties of 2D materials at the nanoscale. Among many 2D materials, graphene and MoS2 have attracted intense interest. Therefore, we applied our

  2. From computational materials science to nanoscale device physics

    NASA Astrophysics Data System (ADS)

    Ghosh, Avik

    2008-10-01

    I will outline formal, computational and device level challenges for modeling and simulation of nanoelectronic devices and systems. Formal challenges involve developing the basic equations for quantum transport in the presence of strong many-body correlations (Coulomb Blockade), incoherent scattering (phonons) and time-dependent effects at the nano-micro interface (hysteretic switching and random telegraph noise). Computational challenges involve translating these equations into quantitative, predictive models, particularly at surfaces and interfaces, where we need practical semi-empirical descriptions with transferable parameters to handle hybrid regions. In addition, we need multiscaling and embedding techniques to merge these models with more detailed ``ab-initio'' descriptions of chemically significant moieties. Finally, Device level challenges involve identifying fundamental limits of existing device paradigms, such as molecular FETs, as well as exploring novel device operational principles. I will touch upon the fundamental issues that arise in context of each challenge, and possible means of solving them. I will then apply these ideas to a specific device architecture, namely, an ordered array of quantum dots grown on the surface of a nanoscale silicon transistor. All of the challenges identified above manifest themselves prominently in this geometry that operates at the nano-micro interface. Specifically, I will discuss how the strongly correlated electrons in the nanoscale dots ``talk'' to their weakly interacting macroscopic counterparts, how the interfacial electronic structure captures both long-ranged band correlations and short-ranged chemical correlations, and how the tunable coupling with the localized dot degrees of freedom can lead to novel physics, such as the experimentally observed blocking and unblocking of a nanotube current by correlated interactions between multiple oxide traps.

  3. Optical Properties of Nanoscale Bismuth Selenide and Its Heterocrystals

    NASA Astrophysics Data System (ADS)

    Vargas, Anthony

    Over the past 12 years since the groundbreaking work on graphene, the field of 2D layered materials has grown by leaps and bounds as more materials are theoretically predicted and experimentically verified. These materials and their unique electronic, optical, and mechanical properties have inspired the scientific community to explore and investigate novel, fundamental physical phenomena as well create and refine technological devices which leverage the host of unique benefits which these materials possess. In the past few years, this burgeoning field has heavily moved towards combining layers of various materials into novel heterostructures. These heterostructures are an exciting area of research because of the plethora of exciting possibilities and results which arise due to the large number of heterostructure combinations and configurations. Particularly, the research into the optical properties of these layered materials and their heterostructures under confinement provides another exciting avenue for developing optoelectric devices. In this dissertation, I present work on the synthesis of Bi2Se 3 nanostructures via chemical vapor deposition (CVD) and the study of the optical properties of these nanostructures and their heterostructures with MoS2. The bulk of the current published work on Bi2Se 3 has focused on the exotic topological properties of its surface states, both interesting fundamental physics purposes as well as for studying avenues for spintronics. In contrast, the work presented here focuses on studying the optical properties of Bi2Se3 nanostructures and how these properties evolve when subjected to confinement. Specifically, the absorbance of singlecrystal Bi2Se3 with sizes tailored down to a few nanometers in diameter and a few quintuple layers (QLs) in thickness. We find a dramatically large bandgap, Eg ≥ 2.5 eV, in the smallest particles which is much higher than that seen in 1QL measurements taken with ARPES. Additionally, utilizing

  4. EDITORIAL: Physical behaviour at the nanoscale: a model for fertile research Physical behaviour at the nanoscale: a model for fertile research

    NASA Astrophysics Data System (ADS)

    Demming, Anna

    2013-06-01

    At the nanoscale physics follows familiar principles that lead to unfamiliar and even unlikely responses. The change in the balance of a range of physical features results in behaviour that can differ wildly from the same materials at the macroscale. In this issue Di Ventra and Pershin examine some of the memory effects that have attracted increasing interest in investigations of nanoscale electronic systems [1]. The work builds on the familiar premise that external perturbations cannot have an instantaneous effect on any condensed matter system. As they point out, 'This is even more so in systems of nanoscale dimensions where the dynamics of a few atoms may affect the whole structure dramatically'. In this way they explain that the response of these systems will always have some degree of memory present and that memristive, memcapacitive and meminductive systems are simply examples where this feature is particularly prominent. In the late 1990s investigations into the use of carbon nanotubes and SiC nanorods revealed that the moduli of these structures changes with diameter, highlighting the eccentricities of mechanical properties at the nanoscale. These results prompted Miller at the University of Saskatchewan and Shenoy at the Indian Institute of Technology to study the properties of nanotubes and nanorods in detail [2]. 'In the eyes of an engineer these structures are essentially little beams', they explained, 'Albeit they are "little" to a degree that challenges our traditional notions of continuum mechanics'. In their work they developed one of the first simple models for explaining the behaviour of the Young's modulus of nanostructures, verified by direct atomistic simulation of axial loading of these structures. Since then, consideration of different nanoscale structures and the dissipation of energy under stress and strain have also demystified the extraordinary mechanical properties of natural materials such as collagen [3] and spider's silk [4]. The

  5. Size Effects on the Magnetic Properties of Nanoscale Particles

    NASA Astrophysics Data System (ADS)

    Chen, Jianping

    Finite size effects on the magnetic properties of nanoscale particles have been studied in this work. The first system studied was MnFe_2O _4 prepared by coprecipitation followed by digestion. The particles were single crystals with an average diameter controllable from 5 nm to 25 nm. These particles have a higher inversion degree of metal ion distribution between the tetrahedral sites and octahedral sites of the spinel structure than those synthesized with ceramic methods. This higher inversion leads to a higher Curie temperature. We found that the structure of the particles can be varied by heat treatment. The Curie temperature of the particles decreased after heat treatment in inert gas, however, it increased after heat treatment in air. The size effects show in two aspects on the MnFe_2O _4 particles. First, the Curie temperature decreased as particles size was reduced, which was explained by finite size scaling. Second, the saturation magnetization decreased as particle size decreased because of the existence of a nonmagnetic layer on the surface of MnFe_2 O_4 particles. The second system studied was Co particles synthesized with an inverse micelle technique. The particles were small (1-5 nm) and had a narrow size distribution. The Co particles were superparamagnetic at room temperature and showed a set of consistent magnetic data in magnetic moment per particle, coercivity, and blocking temperature. We found the anisotropy constant and saturation magnetization of Co particles had a strong size dependence. The anisotropy constant was above the bulk value of Co and increased as particle size decreased. The saturation magnetization increased as the particle became smaller. The magnetic properties of Co particles also strongly suggested a core/shell structure in each particle. But no physical inhomogeneity was observed. We have also studied ligand effects on the magnetic properties of Co particles. The magnetization of the Co particles was quenched by 36%, 27

  6. Properties of nanoscale dielectrics from first principles computations

    NASA Astrophysics Data System (ADS)

    Shi, Ning

    In recent years, dielectric materials of nanoscale dimensions have aroused considerable interest. We mention two examples. First, in the semiconductor industry, in order to keep pace with Moore's law scaling, the thickness of gate oxide dielectric material is reaching nanoscale dimensions. Second, the high energy density capacitor industry is currently considering dielectric composites with a polymer host matrix filled with inorganic dielectric nanoparticles or polarizable organic molecules. The driving force for the former application is high dielectric constants (or high-k), and those for the latter are high-k and/or high dielectric breakdown strengths. Thus, it is important to characterize the electronic and dielectric properties of materials in the nano-regime, where surface and interface effects naturally play a dominant role. The primary goal of this work is to determine the extent to which such surface/interface effects modify the dielectric constants, band edges, and dielectric breakdown strengths of systems with at least one of their dimensions in the nano-regime. Towards that end, we have developed new computational methodologies at the first principles (density functional) level of theory. These methods have then been applied to several relevant and critical nanoscale systems, including Si:SiO2 and Si:HfO2 heterojunctions, and polymeric composites containing Cu-phthalocyanine and SiO2 nanoparticles.

  7. Nanoscale elastic properties of montmorillonite upon water adsorption.

    PubMed

    Ebrahimi, Davoud; Pellenq, Roland J-M; Whittle, Andrew J

    2012-12-11

    Smectites are an important group of clay minerals that experience swelling upon water adsorption. This paper uses molecular dynamics with the CLAYFF force field to simulate isothermal isobaric water adsorption of interlayer Wyoming Na-montmorillonite, a member of the smectite group. Nanoscale elastic properties of the clay-interlayer water system are calculated from the potential energy of the model system. The transverse isotropic symmetry of the elastic constant matrix was assessed by calculating Euclidean and Riemannian distance metrics. Simulated elastic constants of the clay mineral are compared with available results from acoustic and nanoindentation measurements. PMID:23181550

  8. TOPICAL REVIEW: Nanoscale transport properties at silicon carbide interfaces

    NASA Astrophysics Data System (ADS)

    Roccaforte, F.; Giannazzo, F.; Raineri, V.

    2010-06-01

    Wide bandgap semiconductors promise devices with performances not achievable using silicon technology. Among them, silicon carbide (SiC) is considered the top-notch material for a new generation of power electronic devices, ensuring the improved energy efficiency required in modern society. In spite of the significant progress achieved in the last decade in the material quality, there are still several scientific open issues related to the basic transport properties at SiC interfaces and ion-doped regions that can affect the devices' performances, keeping them still far from their theoretical limits. Hence, significant efforts in fundamental research at the nanoscale have become mandatory to better understand the carrier transport phenomena, both at surfaces and interfaces. In this paper, the most recent experiences on nanoscale transport properties will be addressed, reviewing the relevant key points for the basic devices' building blocks. The selected topics include the major concerns related to the electronic transport at metal/SiC interfaces, to the carrier concentration and mobility in ion-doped regions and to channel mobility in metal/oxide/SiC systems. Some aspects related to interfaces between different SiC polytypes are also presented. All these issues will be discussed considering the current status and the drawbacks of SiC devices.

  9. Deciphering the Physical Basis of Biomineralization through Investigations of Nanoscale Growth Processes

    NASA Astrophysics Data System (ADS)

    Dove, P. M.; Davis, K. J.; De Yoreo, J. J.; Orme, C. A.

    2001-12-01

    Microbes and higher organisms direct the formation of complex structures in controlled biomineralization. Using biologically mediated crystallization strategies that have evolved over millenia, organisms have developed the ability to produce nanophase structures as single crystals and composite materials with remarkable properties that fulfill specific functional needs. Modern organisms, as well as those found in the sediment and rock records, chronicle Nature's ability to synthesize sophisticated nanostructures. Although biomineral compositions and their morphologies are windows to interpreting environments of prosperity and decline, most current interpretations lack an understanding of fundamental processes. Hence, the physical basis of biological mineralization continues as one of Nature's best kept secrets. Recently, the biomineralization processes of marine microorganisms have emerged as particularly important owing to the use of biomineral products as paleoclimate indicators. Besides providing critical information on crystal growth history, the minor and trace elements found in these materials also behave as impurities to regulate their properties and formation rates. Using integrated approaches, we are investigating the kinetics and thermodynamics of calcite growth to decipher mechanisms of biomineral formation. Our focus is to link molecular interactions with surface processes and nanoscale controls on crystal morphology. The molecular-scale structure of the crystalline interface is a critical growth determinant, especially when considering nanocrystalline phases. By combining in situ AFM studies of growth that use carefully characterized solution chemistries with molecular modeling and surface spectroscopic investigations, we couple observations of nanoscale growth mechanisms with quantitative kinetic and thermodynamic information. This approach is showing how key inorganic growth impurities, Mg2+ and Sr2+, affect mineralization through complex ion

  10. Physical nanoscale conduit-mediated communication between tumour cells and the endothelium modulates endothelial phenotype

    PubMed Central

    Connor, Yamicia; Tekleab, Sarah; Nandakumar, Shyama; Walls, Cherelle; Tekleab, Yonatan; Husain, Amjad; Gadish, Or; Sabbisetti, Venkata; Kaushik, Shelly; Sehrawat, Seema; Kulkarni, Ashish; Dvorak, Harold; Zetter, Bruce; R. Edelman, Elazer; Sengupta, Shiladitya

    2015-01-01

    Metastasis is a major cause of mortality and remains a hurdle in the search for a cure for cancer. Not much is known about metastatic cancer cells and endothelial cross-talk, which occurs at multiple stages during metastasis. Here we report a dynamic regulation of the endothelium by cancer cells through the formation of nanoscale intercellular membrane bridges, which act as physical conduits for transfer of microRNAs. The communication between the tumour cell and the endothelium upregulates markers associated with pathological endothelium, which is reversed by pharmacological inhibition of these nanoscale conduits. These results lead us to define the notion of ‘metastatic hijack': cancer cell-induced transformation of healthy endothelium into pathological endothelium via horizontal communication through the nanoscale conduits. Pharmacological perturbation of these nanoscale membrane bridges decreases metastatic foci in vivo. Targeting these nanoscale membrane bridges may potentially emerge as a new therapeutic opportunity in the management of metastatic cancer. PMID:26669454

  11. Physical nanoscale conduit-mediated communication between tumour cells and the endothelium modulates endothelial phenotype.

    PubMed

    Connor, Yamicia; Tekleab, Sarah; Nandakumar, Shyama; Walls, Cherelle; Tekleab, Yonatan; Husain, Amjad; Gadish, Or; Sabbisetti, Venkata; Kaushik, Shelly; Sehrawat, Seema; Kulkarni, Ashish; Dvorak, Harold; Zetter, Bruce; R Edelman, Elazer; Sengupta, Shiladitya

    2015-01-01

    Metastasis is a major cause of mortality and remains a hurdle in the search for a cure for cancer. Not much is known about metastatic cancer cells and endothelial cross-talk, which occurs at multiple stages during metastasis. Here we report a dynamic regulation of the endothelium by cancer cells through the formation of nanoscale intercellular membrane bridges, which act as physical conduits for transfer of microRNAs. The communication between the tumour cell and the endothelium upregulates markers associated with pathological endothelium, which is reversed by pharmacological inhibition of these nanoscale conduits. These results lead us to define the notion of 'metastatic hijack': cancer cell-induced transformation of healthy endothelium into pathological endothelium via horizontal communication through the nanoscale conduits. Pharmacological perturbation of these nanoscale membrane bridges decreases metastatic foci in vivo. Targeting these nanoscale membrane bridges may potentially emerge as a new therapeutic opportunity in the management of metastatic cancer. PMID:26669454

  12. Nanoscale lead and noble gas inclusions in aluminum: structures and properties.

    PubMed

    Johnson, Erik; Andersen, Hans Henrik; Dahmen, Ulrich

    2004-08-01

    Transmission electron microscopy has been used for structural and physical characterization of nanoscale inclusions of lead and noble gases in aluminum. When the inclusion sizes approach nanoscale dimensions, many of their properties are seen to deviate from similar properties in bulk and in most cases the deviations will increase as the inclusion sizes decrease. Binary alloys of lead and noble gases with aluminum are characterized by extremely low mutual solubilities and inclusions will, therefore, exist as practically pure components embedded in the aluminum matrix. Furthermore, the thermal vacancy mobility in aluminum at and above room temperature is sufficiently high to accommodate volume strains associated with the inclusions thus leading to virtually strain free crystals. The inclusions grow in parallel cube alignment with the aluminum matrix and have a cuboctahedral shape, which reflects directly the anisotropy of the interfacial energies. Inclusions in grain boundaries can have single crystalline or bicrystalline morphology that can be explained from a generalized Wulff analysis such as the xi-vector construction. The inclusions have been found to display a variety of nanoscale features such as high Laplace pressure, size-dependent superheating during melting, deviations from the Wulff shape displaying magic size effects, a shape dependence of edge energy, and so on. All these effects have been observed and monitored by TEM using conventional imaging conditions and high-resolution conditions in combination with in-situ analysis at elevated temperatures. PMID:15549703

  13. Understanding electronic structure and transport properties in nanoscale junctions

    NASA Astrophysics Data System (ADS)

    Dhungana, Kamal B.

    Understanding the electronic structure and the transport properties of nanoscale materials are pivotal for designing future nano-scale electronic devices. Nanoscale materials could be individual or groups of molecules, nanotubes, semiconducting quantum dots, and biomolecules. Among these several alternatives, organic molecules are very promising and the field of molecular electronics has progressed significantly over the past few decades. Despite these progresses, it has not yet been possible to achieve atomic level control at the metal-molecule interface during a conductance measurement, which hinders the progress in this field. The lack of atomic level information of the interface also makes it much harder for theorist to interpret the experimental results. To identify the junction configuration that possibly exists during the experimental measurement of conductance in molecular junction, we created an ensemble of Ruthanium-bis(terpyridine) molecular devices, and studied the transport behavior in these molecular junctions. This helps us identifying the junction geometry that yields the experimentally measured current-voltage characteristics. Today's electronic devices mostly ignore the spin effect of an electron. The inclusion of spin effect of an electron on solid-state transistor allows us to build more efficient electronic devices; this also alleviates the problem of huge heat dissipation in the nanoscale electronic devices. Different materials have been utilized to build three terminals spin transistor since its inception in 1950. In search of suitable candidates for the molecular spin transistor, we have recently designed a spin-valve transistor based on an organometallic molecule; a large amplification (320 %) in tunnel magneto-resistance (TMR) is found to occur at an experimentally accessible gate field. This suggests that the organic molecules can be utilized for making the next generation three terminal spintronic devices. Similarly, we have designed a

  14. Performance and properties of nanoscale calcium peroxide for toluene removal.

    PubMed

    Qian, Yajie; Zhou, Xuefei; Zhang, Yalei; Zhang, Weixian; Chen, Jiabin

    2013-04-01

    Due to the large diameter and small surface, the contaminant degradation by conventional calcium peroxide (CaO2) is slow with high dosage required. The aggregation of conventional CaO2 also makes it difficult to operate. Nanoscale CaO2 was therefore synthesized and applied to remove toluene in this study. Prepared from nanoscale Ca(OH)2 and H2O2 in the ratio of 1:7, the finely dispersed nanoscale CaO2 particles were confirmed by the scanning electron microscope to be in the range of 100-200nm in size. Compared to their non nanoscale counterparts, the synthesized nanoscale CaO2 demonstrated a superior performance in the degradation of toluene, which could be eliminated in 3d at pH 6. The oxidation products of toluene were analyzed to include benzyl alcohol, benzaldehyde and three cresol isomers. With the addition of 2-propanol, hydroxyl radicals were indicated as the main reactive oxygen species in the oxidation of toluene by nanoscale CaO2. Superoxide radicals were also investigated as the marker of nanoscale CaO2 in the solution. Our study thus provides an important insight into the application of nanoscale CaO2 in the removal of toluene contaminants, which is significant, especially for controlling the petroleum contaminations. PMID:23466092

  15. Understanding nanoscale mechanical properties of materials using ultrafast EUV photoacoustics

    NASA Astrophysics Data System (ADS)

    Hoogeboom-Pot, K.; Turgut, E.; Shaw, J.; Hernandez-Charpak, J.; Murnane, M.; Kapteyn, H.; Nardi, D.

    2014-03-01

    How do the elastic properties of materials evolve as a nanostructure builds up layer by layer? A host of questions in nanoscience, nanotechnology, quantum dot systems and more rely on an answer to this issue; but our ability to probe mechanical properties is severely constrained at dimensions below 100 nm. With tabletop high harmonic generation (HHG), we overcome these limitations by extending non-destructive visible photoacoustics to extreme ultraviolet (EUV) wavelengths. The short wavelength of EUV light, combined with the coherence and ultrashort pulses of HHG creates a unique and powerful probe of nanostructured materials on their intrinsic length and time scales. We study a series of ultrathin bilayer (10-nm Ni/0-6-nm Ta) nanostructures on SiO2 substrates. A femtosecond infrared pulse excites longitudinal acoustic waves (LAWs) within the nanostructures and surface acoustic waves (SAWs) in the substrate. Diffraction of a time-delayed EUV probe pulse monitors the dynamics. LAW resonances are directly related to the bilayer thickness and effective speed of sound; their dependence on Ta-layer thickness reveals that the LAW velocities of both Ni and Ta differ from bulk values. The changing mass of Ta also affects the SAW frequency, allowing us to extract nanoscale densities. This work was supported by the SRC Contract 2012-OJ-2304, by NSF Award No.: DGE 1144083, and used facilities provided by the NSF Engineering Research Center in EUV Science and Technology.

  16. Thermophysical properties study of micro/nanoscale materials

    NASA Astrophysics Data System (ADS)

    Feng, Xuhui

    Thermal transport in low-dimensional structure has attracted tremendous attentions because micro/nanoscale materials play crucial roles in advancing micro/nanoelectronics industry. The thermal properties are essential for understanding of the energy conversion and thermal management. To better investigate micro/nanoscale materials and characterize the thermal transport, pulse laser-assisted thermal relaxation 2 (PLTR2) and transient electrothermal (TET) are both employed to determine thermal property of various forms of materials, including thin films and nanowires. As conducting polymer, Poly(3-hexylthiophene) (P3HT) thin film is studied to understand its thermal properties variation with P3HT weight percentage. 4 P3HT solutions of different weight percentages are compounded to fabricate thin films using spin-coating technique. Experimental results indicate that weight percentage exhibits impact on thermophysical properties. When percentage changes from 2% to 7%, thermal conductivity varies from 1.29 to 1.67 W/m·K and thermal diffusivity decreases from 10-6 to 5×10-7 m2/s. Moreover, PLTR2 technique is applied to characterize the three-dimensional anisotropic thermal properties in spin-coated P3HT thin films. Raman spectra verify that the thin films embrace partially orientated P3HT molecular chains, leading to anisotropic thermal transport. Among all three directions, lowest thermal property is observed along out-of-plane direction. For in-plane characterization, anisotropic ratio is around 2 to 3, indicating that the orientation of the molecular chains has strong impact on the thermal transport along different directions. Titanium dioxide (TiO2) thin film is synthesized by electrospinning features porous structure composed by TiO2 nanowires with random orientations. The porous structure caused significant degradation of thermal properties. Effective thermal diffusivity, conductivity, and density of the films are 1.35˜3.52 × 10-6 m2/s, 0.06˜0.36 W/m·K, and

  17. Structure-property relationships of nanoscale engineered perovskite oxides

    NASA Astrophysics Data System (ADS)

    Tian, Wei

    Recent advances in the synthesis of nanoscale customized structure have demonstrated that reactive molecular beam epitaxy (MBE) can be used to construct nanostructure of oxides with atomic control. The ability to engineer the structure and chemistry of oxides at the nanometer scale makes possible for the creation of new functional materials that can be designed to have exceptional properties. This thesis focused on understanding structure-property relationships of such nanoscale customized oxides utilizing state-of-the-art transmission electron microscopy (TEM). Epitaxial thin films of n = 1--5 members of Ruddlesden-Popper homologous series Srn+1Ti nO3n+1 were synthesized by reactive MBE. We investigated the structure and microstructure of these thin films by x-ray diffraction along with high-resolution transmission electron microscopy (HRTEM) in combination with computer image simulations. We found that the thin films of n = 1--3 members are nearly free of intergrowths, e.g. phase-pure, while n = 4 and 5 thin films contain noticeably more intergrowth defects and anti-phase boundaries in their perovskite sheets. We show that these results are consistent with what is known about the thermodynamics of Sr n+1TinO3 n+1 phases. We also investigated the atomic structure and interfacial structure of artificial PbTiO3/SrTiO3 and BaTiO3/SrTiO 3 superlattices grown by MBE both with and without digital compositional grading. Both of these systems form a solid solution over their entire composition range. Thus, these layered heterostructures are metastable. We demonstrated, however, that the thermodynamically metastable superlattices can be kinetically stabilized via layer-by-layer growth. In addition, we found that the interfaces between two constituents in the heterostructures are atomically-abrupt. The superlattice thin films were made fully coherent with the substrates, resulting in a homogeneous large strain in the BaTiO3 layers due to the lattice mismatch between BaTiO3

  18. Transport Properties of Nanoscale Materials by First-principles Calculations

    NASA Astrophysics Data System (ADS)

    Mizuseki, Hiroshi; Belosludov, Rodion V.; Lee, S.-U.; Kawazoe, Yoshiyuki

    2009-03-01

    Molecular devices are potential candidates for the next step towards nanoelectronic technology. Our group has covered a wide range of nanoscale wires, which have potential application in molecular electronics using first-principles calculations and nonequilibrium Green's function formalism [1]. Our target materials are supramolecular enamel wires (covered wires) [2], connection between organic molecules and metal electrodes, self-assembled nanowires on silicon surface [3], porphyrin [4], phthalocyanine, metallocene [5], fused-ring thiophene molecules, length dependence of conductance in alkanedithiols and so on. Namely, we have investigated a relationship of the energy levels of delocalized frontier orbitals (HOMO and LUMO) and Fermi level of metal electrodes and estimate the electronic transport properties through atomic and molecular wires using Green's function approach. References [1] http://www-lab.imr.edu/˜mizuseki/nanowire.html [2] R. V. Belosludov, A. A. Farajian, H. Baba, H. Mizuseki, and Y. Kawazoe, Jpn. J. Appl. Phys., 44, 2823 (2005). [3] R. V. Belosludov, A. A. Farajian, H. Mizuseki, K. Miki, and Y. Kawazoe, Phys. Rev. B, 75, 113411 (2007). [4] S.-U. Lee, R. V. Belosludov, H. Mizuseki, and Y. Kawazoe, Small 4 (2008) 962. [5] S.-U Lee, R. V. Belosludov, H. Mizuseki, and Y. Kawazoe, J. Phys. Chem. C. 111 (2007) 15397.

  19. Lanthanide upconversion luminescence at the nanoscale: fundamentals and optical properties.

    PubMed

    Nadort, Annemarie; Zhao, Jiangbo; Goldys, Ewa M

    2016-07-01

    Upconversion photoluminescence is a nonlinear effect where multiple lower energy excitation photons produce higher energy emission photons. This fundamentally interesting process has many applications in biomedical imaging, light source and display technology, and solar energy harvesting. In this review we discuss the underlying physical principles and their modelling using rate equations. We discuss how the understanding of photophysical processes enabled a strategic influence over the optical properties of upconversion especially in rationally designed materials. We subsequently present an overview of recent experimental strategies to control and optimize the optical properties of upconversion nanoparticles, focussing on their emission spectral properties and brightness. PMID:26986473

  20. Lanthanide upconversion luminescence at the nanoscale: fundamentals and optical properties

    NASA Astrophysics Data System (ADS)

    Nadort, Annemarie; Zhao, Jiangbo; Goldys, Ewa M.

    2016-07-01

    Upconversion photoluminescence is a nonlinear effect where multiple lower energy excitation photons produce higher energy emission photons. This fundamentally interesting process has many applications in biomedical imaging, light source and display technology, and solar energy harvesting. In this review we discuss the underlying physical principles and their modelling using rate equations. We discuss how the understanding of photophysical processes enabled a strategic influence over the optical properties of upconversion especially in rationally designed materials. We subsequently present an overview of recent experimental strategies to control and optimize the optical properties of upconversion nanoparticles, focussing on their emission spectral properties and brightness.

  1. Physical properties of asteroids

    NASA Technical Reports Server (NTRS)

    Veeder, G. J.

    1986-01-01

    The physical properties of asteroids were studied by telescopic observations and laboratory and theoretical work. Spectrophotometry from 0.3 to 1.1 microns and 1.2, 1.6 and 2.2 micron photometry allow spectral-compositional classification of asteroids. Based on laboratory data and telescopic observations, it was found that infrared measurements at 1.2, 1.6 and 2.2 microns provide a relatively rapid and accurate method for the classification of minor planets and are important in comparing asteroids with meteorites. This technique was proven and employed in an expanded survey of Apollo-Amor-Aten and other unusual asteroids recently scanned by IRAS.

  2. The Properties of Confined Water and Fluid Flow at the Nanoscale

    SciTech Connect

    Schwegler, E; Reed, J; Lau, E; Prendergast, D; Galli, G; Grossman, J C; Cicero, G

    2009-03-09

    This project has been focused on the development of accurate computational tools to study fluids in confined, nanoscale geometries, and the application of these techniques to probe the structural and electronic properties of water confined between hydrophilic and hydrophobic substrates, including the presence of simple ions at the interfaces. In particular, we have used a series of ab-initio molecular dynamics simulations and quantum Monte Carlo calculations to build an understanding of how hydrogen bonding and solvation are modified at the nanoscale. The properties of confined water affect a wide range of scientific and technological problems - including protein folding, cell-membrane flow, materials properties in confined media and nanofluidic devices.

  3. A nanoscale co-precipitation approach for property enhancement of Fe-base alloys

    PubMed Central

    Zhang, Zhongwu; Liu, Chain Tsuan; Miller, Michael K.; Wang, Xun-Li; Wen, Yuren; Fujita, Takeshi; Hirata, Akihiko; Chen, Mingwei; Chen, Guang; Chin, Bryan A.

    2013-01-01

    Precipitate size and number density are two key factors for tailoring the mechanical behavior of nanoscale precipitate-hardened alloys. However, during thermal aging, the precipitate size and number density change, leading to either poor strength or high strength but significantly reduced ductility. Here we demonstrate, by producing nanoscale co-precipitates in composition-optimized multicomponent precipitation-hardened alloys, a unique approach to improve the stability of the alloy against thermal aging and hence the mechanical properties. Our study provides compelling experimental evidence that these nanoscale co-precipitates consist of a Cu-enriched bcc core partially encased by a B2-ordered Ni(Mn, Al) phase. This co-precipitate provides a more complex obstacle for dislocation movement due to atomic ordering together with interphases, resulting in a high yield strength alloy without sacrificing alloy ductility. PMID:23429646

  4. Physical properties of DDGS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Many research studies have examined chemical properties and nutritional characteristics of DDGS, especially in terms of utilization as livestock feed ingredients, their digestibilities, and resulting animal performance. Up until just a few years ago, however, no information was available regarding ...

  5. Nicholas Metropolis Award for Outstanding Doctoral Thesis Work in Computational Physics Talk: Understanding Nano-scale Electronic Systems via Large-scale Computation

    NASA Astrophysics Data System (ADS)

    Cao, Chao

    2009-03-01

    Nano-scale physical phenomena and processes, especially those in electronics, have drawn great attention in the past decade. Experiments have shown that electronic and transport properties of functionalized carbon nanotubes are sensitive to adsorption of gas molecules such as H2, NO2, and NH3. Similar measurements have also been performed to study adsorption of proteins on other semiconductor nano-wires. These experiments suggest that nano-scale systems can be useful for making future chemical and biological sensors. Aiming to understand the physical mechanisms underlying and governing property changes at nano-scale, we start off by investigating, via first-principles method, the electronic structure of Pd-CNT before and after hydrogen adsorption, and continue with coherent electronic transport using non-equilibrium Green’s function techniques combined with density functional theory. Once our results are fully analyzed they can be used to interpret and understand experimental data, with a few difficult issues to be addressed. Finally, we discuss a newly developed multi-scale computing architecture, OPAL, that coordinates simultaneous execution of multiple codes. Inspired by the capabilities of this computing framework, we present a scenario of future modeling and simulation of multi-scale, multi-physical processes.

  6. Cyclic cryopreservation affects the nanoscale material properties of trabecular bone.

    PubMed

    Landauer, Alexander K; Mondal, Sumona; Yuya, Philip A; Kuxhaus, Laurel

    2014-11-01

    Tissues such as bone are often stored via freezing, or cryopreservation. During an experimental protocol, bone may be frozen and thawed a number of times. For whole bone, the mechanical properties (strength and modulus) do not significantly change throughout five freeze-thaw cycles. Material properties at the trabecular and lamellar scales are distinct from whole bone properties, thus the impact of freeze-thaw cycling at this scale is unknown. To address this, the effect of repeated freezing on viscoelastic material properties of trabecular bone was quantified via dynamic nanoindentation. Vertebrae from five cervine spines (1.5-year-old, male) were semi-randomly assigned, three-to-a-cycle, to 0-10 freeze-thaw cycles. After freeze-thaw cycling, the vertebrae were dissected, prepared and tested. ANOVA (factors cycle, frequency, and donor) on storage modulus, loss modulus, and loss tangent, were conducted. Results revealed significant changes between cycles for all material properties for most cycles, no significant difference across most of the dynamic range, and significant differences between some donors. Regression analysis showed a moderate positive correlation between cycles and material property for loss modulus and loss tangent, and weak negative correlation for storage modulus, all correlations were significant. These results indicate that not only is elasticity unpredictably altered, but also that damping and viscoelasticity tend to increase with additional freeze-thaw cycling. PMID:25278046

  7. Physical properties of asteroids

    NASA Technical Reports Server (NTRS)

    Veeder, Glenn J.

    1988-01-01

    Infrared photometry at 1.2, 1.6 and 2.2 micrometer provides a relatively rapid and accurate method for the classification of asteroids and is important for comparison with laboratory measurements of meteorites and other possible compositional analogues. Extension beyond the visual is espicially useful for minerals which have strong characteristic infrared colors such as olivine in the A class asteroids. Radiometry at long infrared wavelengths is important for deriving basic physical parameters (via thermal models) such as size and albedo which in turn enables the conversion of relative colors to absolute reflectances. In particular, albedos are the only way to distinguish among the otherwise ambiguous E, M and P classes of asteroids. Infrared observations of 15 asteroids were made at the NASA infrared Telescope Facility (IRTF) on Mauna Kea in 1987. Researchers completed the analysis of 22 Aten, Apollo and Amor asteroids. Results include albedos and diameters for these objects as well as the identification of the first known class M and Class E near-Earth asteroids. The standard thermal model appears to be inadequate for some of these small asteroids because of their coarse regolith, so researchers constructed a rotating thermal model for such asteroids. They have identified a subtle systematic difference between the sub-populations of large and small IRAS asteroids as well as several anomalous objects.

  8. Nanoscale Atomic Displacements Ordering for Enhanced Piezoelectric Properties in Lead-Free ABO3 Ferroelectrics.

    PubMed

    Pramanick, Abhijit; Jørgensen, Mads R V; Diallo, Souleymane O; Christianson, Andrew D; Fernandez-Baca, Jaime A; Hoffmann, Christina; Wang, Xiaoping; Lan, Si; Wang, Xun-Li

    2015-08-01

    In situ synchrotron X-ray diffuse scattering and inelastic neutron scattering measurements from a prototype ABO3 ferroelectric single-crystal are used to elucidate how electric fields along a nonpolar direction can enhance its piezoelectric properties. The central mechanism is found to be a nanoscale ordering of B atom displacements, which induces increased lattice instability and therefore a greater susceptibility to electric-field-induced mechanical deformation. PMID:26076654

  9. Analytical model for nanoscale viscoelastic properties characterization using dynamic nanoindentation

    NASA Astrophysics Data System (ADS)

    Yuya, Philip A.; Patel, Nimitt G.

    2014-08-01

    In the last few decades, nanoindentation has gained widespread acceptance as a technique for materials properties characterization at micron and submicron length scales. Accurate and precise characterization of material properties with a nanoindenter is critically dependent on the ability to correctly model the response of the test equipment in contact with the material. In dynamic nanoindention analysis, a simple Kelvin-Voigt model is commonly used to capture the viscoelastic response. However, this model oversimplifies the response of real viscoelastic materials such as polymers. A model is developed that captures the dynamic nanoindentation response of a viscoelastic material. Indenter tip-sample contact forces are modelled using a generalized Maxwell model. The results on a silicon elastomer were analysed using conventional two element Kelvin-Voigt model and contrasted to analysis done using the Maxwell model. The results show that conventional Kelvin-Voigt model overestimates the storage modulus of the silicone elastomer by ~30%. Maxwell model represents a significant improvement in capturing the viscoelastic material behaviour over the Voigt model.

  10. Predictive atomistic simulations of electronic properties of realistic nanoscale devices: A multiscale modeling approach

    NASA Astrophysics Data System (ADS)

    Vedula, Ravi Pramod Kumar

    Scaling of CMOS towards its ultimate limits, where quantum effects and atomistic variability due to fabrication, along with recent emphasis on heterogeneous integration of non-digital devices for increasing the functional diversification presents us with fundamentally new challenges. A comprehensive understanding of design and operation of these nanoscale transistors, and other electronic devices like RF-MEMS, requires an insight into their electronic and mechanical properties that are strongly influenced by underlying atomic structure. Hence, continuum descriptions of materials and use of empirical models at these scales become questionable. This increase in complexity of electronic devices necessitates an understanding at a more fundamental level to accurately predict the performance and reliability of these devices. The objective of this thesis is to outline the application of multiscale predictive modeling methods, ranging from atoms to devices, for addressing these challenges. This capability is demonstrated using two examples: characterization of (i) dielectric charging in RF-MEMS, and (ii) transport properties of Ge-nanofins. For characterizing the dielectric charging phenomenon, a continuum dielectric charging model, augmented by first principles informed trap distributions, is used to predict current transient measurements across a broad range of voltages and temperatures. These simulations demonstrate using ab initio informed model not only reduces the empiricism (number of adjustable parameters) in the model but also leads to a more accurate model over a broad range of operating conditions, and enable the precise determination of additional material parameters. These atomistic calculations also provide detailed information about the nature of charge traps and their trapping mechanisms that are not accessible experimentally; such information could prove invaluable in defect engineering. The second problem addresses the effect of the in-homogeneous strain

  11. Lattice Dynamical Properties of Ferroelectric Thin Films at the Nanoscale

    SciTech Connect

    Xi, Xiaoxing

    2014-01-13

    In this project, we have successfully demonstrated atomic layer-by-layer growth by laser MBE from separate targets by depositing SrTiO3 films from SrO and TiO2 targets. The RHEED intensity oscillation was used to monitor and control the growth of each SrO and TiO2 layer. We have shown that by using separate oxide targets, laser MBE can achieve the same level of stoichiometry control as the reactive MBE. We have also studied strain relaxation in LaAlO3 films and its effect on the 2D electron gas at LaAlO3/SrTiO3 interface. We found that there are two layers of different in-plane lattice constants in the LaAlO3 films, one next to the SrTiO3 substrate nearly coherently strained, while the top part relaxed as the film thickness increases above 20 unit cells. This strain relaxation significantly affect the transport properties of the LaAlO3/SrTiO3 interface.

  12. Novel nanostructured thin film heterostructures: Growth, nanoscale characterization and properties

    NASA Astrophysics Data System (ADS)

    Chugh, Amit

    heterostructures was carried out by Pulsed laser deposition and laser MBE. The epitaxial relationships are given in each case are shown to be due to domain matching epitaxy. X-Ray diffraction and Transmission Electron Microscopy studies confirm the relationship between film and substrate. Also, electrical and optical measurements were done, in order to study the change in these properties.

  13. Cesium Eluate Physical Property Determination

    SciTech Connect

    Baich, M.A.

    2001-02-13

    Two bench-scale process simulations of the proposed cesium eluate evaporation process of concentrating eluate produced in the Hanford Site Waste Treatment Plant were conducted. The primary objective of these experiments was to determine the physical properties and the saturation concentration of the eluate evaporator bottoms while producing condensate approximately 0.50 molar HN03.

  14. Physical properties of psyllium seed

    NASA Astrophysics Data System (ADS)

    Ahmadi, R.; Kalbasi-Ashtari, A.; Gharibzahedi, S.

    2012-02-01

    Physical properties ie dimensions, volume, surface area, sphericity, true density, porosity, angle of repose, terminal velocity, static and dynamic friction coefficients on plywood, stainless steel, glass and galvanized iron sheet, force required for initiating seed rupture in horizontal and vertical orientations of psyllium seed at a moisture content of 7.2% (w.b.)were determined.

  15. Advances in imaging and quantification of electrical properties at the nanoscale using Scanning Microwave Impedance Microscopy (sMIM)

    NASA Astrophysics Data System (ADS)

    Friedman, Stuart; Stanke, Fred; Yang, Yongliang; Amster, Oskar

    Scanning Microwave Impedance Microscopy (sMIM) is a mode for Atomic Force Microscopy (AFM) enabling imaging of unique contrast mechanisms and measurement of local permittivity and conductivity at the 10's of nm length scale. sMIM has been applied to a variety of systems including nanotubes, nanowires, 2D materials, photovoltaics and semiconductor devices. Early results were largely semi-quantitative. This talk will focus on techniques for extracting quantitative physical parameters such as permittivity, conductivity, doping concentrations and thin film properties from sMIM data. Particular attention will be paid to non-linear materials where sMIM has been used to acquire nano-scale capacitance-voltage curves. These curves can be used to identify the dopant type (n vs p) and doping level in doped semiconductors, both bulk samples and devices. Supported in part by DOE-SBIR DE-SC0009856.

  16. Nanoscale investigation of the piezoelectric properties of perovskite ferroelectrics and III-nitrides

    NASA Astrophysics Data System (ADS)

    Rodriguez, Brian Joseph

    Nanoscale characterization of the piezoelectric and polarization related properties of III-Nitrides by piezoresponse force microscopy (PFM), electrostatic force microscopy (EFM) and scanning Kelvin probe microscopy (SKPM) resulted in the measurement of piezoelectric constants, surface charge and surface potential. Photo-electron emission microscopy (PEEM) was used to determine the local electronic band structure of a GaN-based lateral polarity heterostructure (GaN-LPH). Nanoscale characterization of the imprint and switching behavior of ferroelectric thin films by PFM resulted in the observation of domain pinning, while nanoscale characterization of the spatial variations in the imprint and switching behavior of integrated (111)-oriented PZT-based ferroelectric random access memory (FRAM) capacitors by PFM have revealed a significant difference in imprint and switching behavior between the inner and outer parts of capacitors. The inner regions of the capacitors are typically negatively imprinted and consequently tend to switch back after being poled by a positive bias, while regions at the edge of the capacitors tend to exhibit more symmetric hysteresis behavior. Evidence was obtained indicating that mechanical stress conditions in the central regions of the capacitors can lead to incomplete switching. A combination of vertical and lateral piezoresponse force microscopy (VPFM and LPFM, respectively) has been used to map the out-of-plane and in-plane polarization distribution, respectively, of integrated (111)-oriented PZT-based capacitors, which revealed poled capacitors are in a polydomain state.

  17. The effect of growth temperature on the nanoscale biochemical surface properties of Yersinia pestis.

    PubMed

    Wang, Congzhou; Stanciu, Cristina E; Ehrhardt, Christopher J; Yadavalli, Vamsi K

    2016-08-01

    Yersinia pestis, the causative agent of plague, has been responsible for several recurrent, lethal pandemics in history. Currently, it is an important pathogen to study owing to its virulence, adaptation to different environments during transmission, and potential use in bioterrorism. Here, we report on the changes to Y. pestis surfaces in different external microenvironments, specifically culture temperatures (6, 25, and 37 °C). Using nanoscale imaging coupled with functional mapping, we illustrate that changes in the surfaces of the bacterium from a morphological and biochemical standpoint can be analyzed simultaneously using atomic force microscopy. The results from functional mapping, obtained at a single cell level, show that the density of lipopolysaccharide (measured via terminal N-acetylglucosamine) on Y. pestis grown at 37 °C is only slightly higher than cells grown at 25 °C, but nearly three times higher than cells maintained at 6 °C for an extended period of time, thereby demonstrating that adaptations to different environments can be effectively captured using this technique. This nanoscale evaluation provides a new microscopic approach to study nanoscale properties of bacterial pathogens and investigate adaptations to different external environments. PMID:27259520

  18. Nanoscale Properties and Stability Simulations of Alkali Activated Cement Phases from First Principle Calculations

    NASA Astrophysics Data System (ADS)

    Ozcelik, Ongun; White, Claire

    Using first principle density functional calculations, we present the nanoscale properties of interactions, local bonds, charge distributions, mechanical properties and strength of alkali activated cement phases which are the most promising alternative to the ordinary Portland cement with a much lower cost to the environment. We present results on the stability and long term durability of various alkali activated cement structures, effects of external alkali agents on their properties and ways of utilizing them for further applications. We compare the calculated properties of alkali activated cement with those of ordinary Portland cement and contribute to the formation of long term durability data of these phases. Comparison with X-ray and neutron scattering experiment results are also provided via pair distribution functions extracted from simulation results.

  19. Nanoscale electrical property studies of individual GeSi quantum rings by conductive scanning probe microscopy

    PubMed Central

    2012-01-01

    The nanoscale electrical properties of individual self-assembled GeSi quantum rings (QRs) were studied by scanning probe microscopy-based techniques. The surface potential distributions of individual GeSi QRs are obtained by scanning Kelvin microscopy (SKM). Ring-shaped work function distributions are observed, presenting that the QRs' rim has a larger work function than the QRs' central hole. By combining the SKM results with those obtained by conductive atomic force microscopy and scanning capacitance microscopy, the correlations between the surface potential, conductance, and carrier density distributions are revealed, and a possible interpretation for the QRs' conductance distributions is suggested. PMID:23194252

  20. Physical Origins of Thermal Properties of Cement Paste

    NASA Astrophysics Data System (ADS)

    Abdolhosseini Qomi, Mohammad Javad; Ulm, Franz-Josef; Pellenq, Roland J.-M.

    2015-06-01

    Despite the ever-increasing interest in multiscale porous materials, the chemophysical origin of their thermal properties at the nanoscale and its connection to the macroscale properties still remain rather obscure. In this paper, we link the atomic- and macroscopic-level thermal properties by combining tools of statistical physics and mean-field homogenization theory. We begin with analyzing the vibrational density of states of several calcium-silicate materials in the cement paste. Unlike crystalline phases, we indicate that calcium silicate hydrates (CSH) exhibit extra vibrational states at low frequencies (<2 THz ) compared to the vibrational states predicted by the Debye model. This anomaly is commonly referred to as the boson peak in glass physics. In addition, the specific-heat capacity of CSH in both dry and saturated states scales linearly with the calcium-to-silicon ratio. We show that the nanoscale-confining environment of CSH decreases the apparent heat capacity of water by a factor of 4. Furthermore, full thermal conductivity tensors for all phases are calculated via the Green-Kubo formalism. We estimate the mean free path of phonons in calcium silicates to be on the order of interatomic bonds. This satisfies the scale separability condition and justifies the use of mean-field homogenization theories for upscaling purposes. Upscaling schemes yield a good estimate of the macroscopic specific-heat capacity and thermal conductivity of cement paste during the hydration process, independent of fitting parameters.

  1. Mapping the mechanical properties of cholesterol-containing supported lipid bilayers with nanoscale spatial resolution.

    PubMed

    Shamitko-Klingensmith, Nicole; Molchanoff, Kelley M; Burke, Kathleen A; Magnone, George J; Legleiter, Justin

    2012-09-18

    It has been demonstrated that many biological processes are influenced by mechanical changes in membranes comprised of a variety of lipid components. As a result, the ability to map physicomechanical properties of surfaces with high temporal and spatial resolution is desirable. Tapping mode atomic force microscopy (AFM) has proven to be a useful technique for imaging biological surfaces due to its ability to operate in solution; however, access to information concerning the mechanical properties of these surfaces can also be obtained by reconstructing the time-resolved tip/sample force interactions during the imaging process. An advantage of such an approach is the direct correlation of topographical features with mechanical properties. Reconstruction of the tip/sample force is achievable by a technique called scanning probe acceleration microscopy (SPAM), which treats the cantilever as an accelerometer. The acceleration, which is directly related to the tip/sample force, of the cantilever is obtained by taking the second derivative of the cantilever deflection signal during a tapping mode AFM experiment in solution with standard cantilevers. Herein, we describe the applicability of SPAM to study mechanical properties of supported lipid bilayers with nanoscale spatial resolution via numerical simulations and experiment. The maximum and minimum tapping forces respond to changes in specific surface mechanical properties. Furthermore, we demonstrate how these changes can be used to map relative changes in the Young's modulus and adhesive properties of supported total brain lipid extract bilayers containing exogenous cholesterol. Finally, the ability of SPAM to distinguish nanoscale lipid raft domains based on changes in local mechanical properties is demonstrated. PMID:22924735

  2. Nanoscale 2013

    NASA Astrophysics Data System (ADS)

    Koenders, Ludger; Ducourtieux, Sebastien

    2014-04-01

    The accurate determination of the properties of micro- and nano-structures is essential in research and development. It is also a prerequisite in process control and quality assurance in industry. In most cases, especially at the nanometer range, knowledge of the dimensional properties of structures is the fundamental base, to which further physical properties are linked. Quantitative measurements presuppose reliable and stable instruments, suitable measurement procedures as well as calibration artifacts and methods. This special issue of Measurement Science and Technology presents selected contributions from the NanoScale 2013 seminar held in Paris, France, on 25 and 26 April. It was the 6th Seminar on NanoScale Calibration Standards and Methods and the 10th Seminar on Quantitative Microscopy (the first being held in 1995). The seminar was jointly organized with the Nanometrology Group of the Technical Committee-Length of EURAMET, the Physikalisch-Technische Bundesanstalt and the Laboratoire National de Métrologie et d'Essais. Three satellite meetings related to nanometrology were coupled to the seminar. The first one was an open Symposium on Scanning Probe Microscopy Standardization organized by the ISO/TC 201/SC9 technical committee. The two others were specific meetings focused on two European Metrology Research Projects funded by the European Association of National Metrology Institutes (EURAMET) (see www.euramet.org), the first one focused on the improvement of the traceability for high accuracy devices dealing with sub-nm length measurement and implementing optical interferometers or capacitive sensors (JRP SIB08 subnano), the second one aiming to develop a new metrological traceability for the measurement of the mechanical properties of nano-objects (JRP NEW05 MechProNo). More than 100 experts from industry, calibration laboratories and metrology institutes from around the world joined the NanoScale 2013 Seminar to attend 23 oral and 64 poster

  3. The Effects of Nanoscale Exsolution on Magnetic Properties: Insights From FORC Diagrams

    NASA Astrophysics Data System (ADS)

    McEnroe, S.; Hirt, A. M.; Harrison, R.; Robinson, P.; Brown, L.

    2005-12-01

    Samples of igneous and metamorphic rocks from the USA, Canada, Chile, Sweden, Norway and Australia contain oxides of either nearly `pure hematite' or from the hematite-ilmenite solid solution series. Samples with oxides from the hematite-ilmenite solid solution series all have nanoscale exsolution of hematite and ilmenite that formed as a chemical remanent magnetization (CRM) during cooling from igneous or metamorphic settings. The nearly pure hematite samples show relic exsolution of spinel and/or extensive twinning in the hematite. Hysteresis properties have been measured from 10 K to 300 K on most samples and to 900K on selected samples. All samples contain a hematite component either as exsolution lamellae, as the host material, or as a nearly pure oxide phase. Variations in room temperature coercivity ranged from 9mT to 440mT. With this large range in hysteresis behavior FORC measurements were made to help separate the possibilities of 1) co-existing phases, 2) exchange coupling or interactions and 3) contributions from the nanoscale exsolution. It is important to note that a saturated state may not have been reached at the start of the FORC measurements for the higher coercivity samples. However, FORC diagrams on samples with two or more oxides were very helpful in determining the contributions to the bulk coercivity of the different minerals. Numerous samples with exsolution showed distinct negative peak value of Hu. Separating out whether this response is due to the fact that these samples contain hematite, or due to interaction within the oxides is open to speculation. Most of the examined samples contained nanoscale exsolution as imaged with TEM, all had a negative Hu and the amount of displacement varied strongly. The amount of displacement cannot be correlated directly to the size, or spacing of the lamellae. Correlation of the distribution of Hc and Hu with TEM images and other rock magnetic properties will be discussed.

  4. Nanoscale investigation of the electrical properties in semiconductor polymer-carbon nanotube hybrid materials

    NASA Astrophysics Data System (ADS)

    Desbief, Simon; Hergué, Noémie; Douhéret, Olivier; Surin, Mathieu; Dubois, Philippe; Geerts, Yves; Lazzaroni, Roberto; Leclère, Philippe

    2012-03-01

    The morphology and electrical properties of hybrids of a semiconducting polymer (namely poly(3-hexylthiophene) P3HT) and carbon nanotubes are investigated at the nanoscale with a combination of Scanning Probe Microscopy techniques, i.e., Conductive Atomic Force Microscopy (C-AFM) and time-resolved Current Sensing Force Spectroscopy Atomic Force Microscopy (CSFS-AFM, or PeakForce TUNA™). This allows us to probe the electrical properties of the 15 nm wide P3HT nanofibers as well as the interface between the polymer and single carbon nanotubes. This is achieved by applying controlled, low forces on the tip during imaging, which allows a direct comparison between the morphology and the electrical properties at the nanometre scale.The morphology and electrical properties of hybrids of a semiconducting polymer (namely poly(3-hexylthiophene) P3HT) and carbon nanotubes are investigated at the nanoscale with a combination of Scanning Probe Microscopy techniques, i.e., Conductive Atomic Force Microscopy (C-AFM) and time-resolved Current Sensing Force Spectroscopy Atomic Force Microscopy (CSFS-AFM, or PeakForce TUNA™). This allows us to probe the electrical properties of the 15 nm wide P3HT nanofibers as well as the interface between the polymer and single carbon nanotubes. This is achieved by applying controlled, low forces on the tip during imaging, which allows a direct comparison between the morphology and the electrical properties at the nanometre scale. Electronic supplementary information (ESI) available. See DOI: 10.1039/c2nr11888b

  5. Visualizing nanoscale excitonic relaxation properties of disordered edges and grain boundaries in monolayer molybdenum disulfide

    DOE PAGESBeta

    Bao, Wei; Borys, Nicholas J.; Ko, Changhyun; Suh, Joonki; Fan, Wen; Thron, Andrew; Zhang, Yingjie; Buyanin, Alexander; Zhang, Jie; Cabrini, Stefano; et al

    2015-08-13

    The ideal building blocks for atomically thin, flexible optoelectronic and catalytic devices are two-dimensional monolayer transition metal dichalcogenide semiconductors. Although challenging for two-dimensional systems, sub-diffraction optical microscopy provides a nanoscale material understanding that is vital for optimizing their optoelectronic properties. We use the ‘Campanile’ nano-optical probe to spectroscopically image exciton recombination within monolayer MoS2 with sub-wavelength resolution (60 nm), at the length scale relevant to many critical optoelectronic processes. Moreover, synthetic monolayer MoS2 is found to be composed of two distinct optoelectronic regions: an interior, locally ordered but mesoscopically heterogeneous two-dimensional quantum well and an unexpected ~300-nm wide, energetically disorderedmore » edge region. Further, grain boundaries are imaged with sufficient resolution to quantify local exciton-quenching phenomena, and complimentary nano-Auger microscopy reveals that the optically defective grain boundary and edge regions are sulfur deficient. In conclusion, the nanoscale structure–property relationships established here are critical for the interpretation of edge- and boundary-related phenomena and the development of next-generation two-dimensional optoelectronic devices.« less

  6. Visualizing nanoscale excitonic relaxation properties of disordered edges and grain boundaries in monolayer molybdenum disulfide

    SciTech Connect

    Bao, Wei; Borys, Nicholas J.; Ko, Changhyun; Suh, Joonki; Fan, Wen; Thron, Andrew; Zhang, Yingjie; Buyanin, Alexander; Zhang, Jie; Cabrini, Stefano; Ashby, Paul D.; Weber-Bargioni, Alexander; Tongay, Sefaattin; Aloni, Shaul; Ogletree, D. Frank; Wu, Junqiao; Salmeron, Miquel B.; Schuck, P. James

    2015-08-13

    The ideal building blocks for atomically thin, flexible optoelectronic and catalytic devices are two-dimensional monolayer transition metal dichalcogenide semiconductors. Although challenging for two-dimensional systems, sub-diffraction optical microscopy provides a nanoscale material understanding that is vital for optimizing their optoelectronic properties. We use the ‘Campanile’ nano-optical probe to spectroscopically image exciton recombination within monolayer MoS2 with sub-wavelength resolution (60 nm), at the length scale relevant to many critical optoelectronic processes. Moreover, synthetic monolayer MoS2 is found to be composed of two distinct optoelectronic regions: an interior, locally ordered but mesoscopically heterogeneous two-dimensional quantum well and an unexpected ~300-nm wide, energetically disordered edge region. Further, grain boundaries are imaged with sufficient resolution to quantify local exciton-quenching phenomena, and complimentary nano-Auger microscopy reveals that the optically defective grain boundary and edge regions are sulfur deficient. In conclusion, the nanoscale structure–property relationships established here are critical for the interpretation of edge- and boundary-related phenomena and the development of next-generation two-dimensional optoelectronic devices.

  7. Visualizing nanoscale excitonic relaxation properties of disordered edges and grain boundaries in monolayer molybdenum disulfide

    PubMed Central

    Bao, Wei; Borys, Nicholas J.; Ko, Changhyun; Suh, Joonki; Fan, Wen; Thron, Andrew; Zhang, Yingjie; Buyanin, Alexander; Zhang, Jie; Cabrini, Stefano; Ashby, Paul D.; Weber-Bargioni, Alexander; Tongay, Sefaattin; Aloni, Shaul; Ogletree, D. Frank; Wu, Junqiao; Salmeron, Miquel B.; Schuck, P. James

    2015-01-01

    Two-dimensional monolayer transition metal dichalcogenide semiconductors are ideal building blocks for atomically thin, flexible optoelectronic and catalytic devices. Although challenging for two-dimensional systems, sub-diffraction optical microscopy provides a nanoscale material understanding that is vital for optimizing their optoelectronic properties. Here we use the ‘Campanile' nano-optical probe to spectroscopically image exciton recombination within monolayer MoS2 with sub-wavelength resolution (60 nm), at the length scale relevant to many critical optoelectronic processes. Synthetic monolayer MoS2 is found to be composed of two distinct optoelectronic regions: an interior, locally ordered but mesoscopically heterogeneous two-dimensional quantum well and an unexpected ∼300-nm wide, energetically disordered edge region. Further, grain boundaries are imaged with sufficient resolution to quantify local exciton-quenching phenomena, and complimentary nano-Auger microscopy reveals that the optically defective grain boundary and edge regions are sulfur deficient. The nanoscale structure–property relationships established here are critical for the interpretation of edge- and boundary-related phenomena and the development of next-generation two-dimensional optoelectronic devices. PMID:26269394

  8. Viscoelastic properties of polymer surfaces investigated by nanoscale dynamic mechanical analysis

    NASA Astrophysics Data System (ADS)

    Chakravartula, A.; Komvopoulos, K.

    2006-03-01

    The viscoelastic properties of polymer surfaces were investigated by nanoscale dynamic mechanical analysis (nano-DMA) involving contact force modulation in the frequency range of 10-200Hz. Nano-DMA experiments were performed with a Berkovich diamond tip of nominal radius of curvature equal to ˜100nm under a mean contact force of 8-10μN and alternating force equal to 2% of the mean force. Variations in the loss tangent, storage modulus, and loss modulus of low- and high-density polyethylene and ultrahigh molecular weight polyethylene with the force frequency demonstrated significantly different viscoelastic behaviors for shallow depths (<40nm) than for relatively large depths (i.e., 75-100nm). The effects of alternating force frequency and indentation depth on the viscoelastic properties of the different polyethylene materials are interpreted in terms of the microstructure characteristics and the molecular chain mobility at the polymer surfaces. The results show that nano-DMA is an effective technique for nanoscale studies of the viscoelastic behavior of polymer surfaces.

  9. Regenerator matrix physical property data

    NASA Technical Reports Server (NTRS)

    Fucinari, C. A.

    1980-01-01

    Among several cellular ceramic structures manufactured by various suppliers for regenerator application in a gas turbine engine, three have the best potential for achieving durability and performance objectives for use in gas turbines, Stirling engines, and waste heat recovery systems: (1) an aluminum-silicate sinusoidal flow passage made from a corrugated wate paper process; (2) an extruded isosceles triangle flow passage; and (3) a second generation matrix incorporating a square flow passage formed by an embossing process. Key physical and thermal property data for these configurations presented include: heat transfer and pressure drop characteristics, compressive strength, tensile strength and elasticity, thermal expansion characteristics, chanical attack, and thermal stability.

  10. Physical properties of asteroid families

    NASA Astrophysics Data System (ADS)

    Masiero, J.; DeMeo, F.; Kasuga, T.; Parker, A.

    2014-07-01

    Asteroid families are created when a parent body undergoes a cratering or collisional disruption event, forming a population of smaller asteroids that initially have orbital elements similar to the parent. Members of asteroid families should also show a compositional similarity indicative of their lineage. This can be observed by comparing colors, spectra, and albedos of family members to each other and to the background population, and can be used to improve family associations by rejecting background objects and extending the search space. In this talk, we review the new data that has become available over the last decade from large-scale surveys of asteroid physical properties, recent work using these datasets to investigate family properties, and how this wealth of information has expanded our understanding of the formation and evolution of asteroid families. This work will be detailed in an upcoming chapter of the ''Asteroids IV'' book in 2015.

  11. Coherence properties of blackbody radiation and application to energy harvesting and imaging with nanoscale rectennas

    NASA Astrophysics Data System (ADS)

    Lerner, Peter B.; Cutler, Paul H.; Miskovsky, Nicholas M.

    2015-01-01

    Modern technology allows the fabrication of antennas with a characteristic size comparable to the electromagnetic wavelength in the optical region. This has led to the development of new technologies using nanoscale rectifying antennas (rectennas) for solar energy conversion and sensing of terahertz, infrared, and visible radiation. For example, a rectenna array can collect incident radiation from an emitting source and the resulting conversion efficiency and operating characteristics of the device will depend on the spatial and temporal coherence properties of the absorbed radiation. For solar radiation, the intercepted radiation by a micro- or nanoscale array of devices has a relatively narrow spatial and angular distribution. Using the Van Cittert-Zernike theorem, we show that the coherence length (or radius) of solar radiation on an antenna array is, or can be, tens of times larger than the characteristic wavelength of the solar spectrum, i.e., the thermal wavelength, λT=2πℏc/(kBT), which for T=5000 K is about 3 μm. Such an effect is advantageous, making possible the rectification of solar radiation with nanoscale rectenna arrays, whose size is commensurate with the coherence length. Furthermore, we examine the blackbody radiation emitted from an array of antennas at temperature T, which can be quasicoherent and lead to a modified self-image, analogous to the Talbot-Lau self-imaging process but with thermal rather than monochromatic radiation. The self-emitted thermal radiation may be important as a nondestructive means for quality control of the array.

  12. An atomic force microscopy tip model for investigating the mechanical properties of materials at the nanoscale.

    PubMed

    Alderighi, Michele; Ierardi, Vincenzo; Allegrini, Maria; Fuso, Francesco; Solaro, Roberto

    2008-05-01

    Investigation of the mechanical properties of materials at the nanoscale is often performed by atomic force microscopy nanoindentation. However, substrates with large surface roughness and heterogeneity demand careful data analysis. This requirement is even more stringent when surface indentations with a typical depth of a few nanometers are produced to test material hardness. Accordingly, we developed a geometrical model of the nanoindenter, which was first validated by measurements on a reference gold sample. Then we used this technique to investigate the mechanical properties of a coating layer made of Balinit C, a commercially available alloy with superior anti-wear features deposited on steel. The reported results support the feasibility of reliable hardness measurements with truly nanosized indents. PMID:18572668

  13. A nanoscale duplex precipitation approach for improving the properties of Fe-base alloys

    SciTech Connect

    Zhang, Zhongwu; Liu, C T; Wang, Xun-Li; Wen, Y. R.; Fujita, T.; Hirata, A.; Chen, M.W.; Miller, Michael K; Chen, Guang; Chin, Bryan

    2013-01-01

    The precipitate size and number density are important factors for tailoring the mechanical behaviors of nanoscale precipitate-hardened alloys. However during thermal aging, the precipitate size and number density change leading to either poor strength or high strength but significantly reduced ductility. Here we demonstrate, by producing nanoprecipitates with unusual duplex structures in a composition-optimized multicomponent precipitation-hardened alloy, a unique approach to improve the stability of the alloy against the effects of thermal aging and consequently change in the mechanical properties. Our study provides compelling experimental evidence that these nanoscale precipitates consist of a duplex structures with a Cu-enriched bcc core that is partially encased by a B2-ordered Ni(Mn,Al) phase. This duplex structure enables the precipitate size and number density to be independently optimized, provides a more complex obstacle for dislocation movement due to the ordering and an additional interphase interface, and yields a high yield strength alloy without sacrificing the ductility.

  14. Nanoscale Mapping of Dielectric Properties of Nanomaterials from Kilohertz to Megahertz Using Ultrasmall Cantilevers.

    PubMed

    Cadena, Maria J; Sung, Seung Hyun; Boudouris, Bryan W; Reifenberger, Ronald; Raman, Arvind

    2016-04-26

    Electrostatic force microscopy (EFM) is often used for nanoscale dielectric spectroscopy, the measurement of local dielectric properties of materials as a function of frequency. However, the frequency range of atomic force microscopy (AFM)-based dielectric spectroscopy has been limited to a few kilohertz by the resonance frequency and noise of soft microcantilevers used for this purpose. Here, we boost the frequency range of local dielectric spectroscopy by 3 orders of magnitude from a few kilohertz to a few megahertz by developing a technique that exploits the high resonance frequency and low thermal noise of ultrasmall cantilevers (USCs). We map the frequency response of the real and imaginary components of the capacitance gradient (∂C(ω)/∂z) by using second-harmonic EFM and a theoretical model, which relates cantilever dynamics to the complex dielectric constant. We demonstrate the method by mapping the nanoscale dielectric spectrum of polymer-based materials for organic electronic devices. Beyond offering a powerful extension to AFM-based dielectric spectroscopy, the approach also allows the identification of electrostatic excitation frequencies which affords high dielectric contrast on nanomaterials. PMID:26972782

  15. [PHYSICAL PROPERTIES OF PLASTER BANDAGES].

    PubMed

    Antabak, Anko; Barisić, Branimir; Andabak, Matej; Bradić, Lucija; Brajcinović, Melita; Haramina, Tatjana; Haluzan, Damir; Fuchs, Nino; Durkovir, Selena; Curković, Selena; Luetić, Tomislav; Sisko, Jerko; Prlić, Ivica

    2015-01-01

    The physical properties of plaster bandages are a very important factor in achieving the basic functions of immobilization (maintaining bone fragments in the best possible position), which directly affects the speed and quality of fracture healing. This paper compares the differences between the physical properties of plaster bandages (mass, specific weight, drying rate, elasticity and strength) and records the differences in plaster modeling of fast bonding 10 cm wide plaster bandages, from three different manufacturers: Safix plus (Hartmann, Germany), Cellona (Lohman Rauscher, Austria) and Gipsan (Ivo Lola Ribar ltd., Croatia). Plaster tiles from ten layers of plaster, dimension 10 x 10 cm were made. The total number of tiles from each manufacturer was 48. The water temperature of 22 °C was used for the first 24 tiles and 34 'C was used for the remainder. The average specific weight of the original packaging was: Cellona (0.52 g/cm3), Gipsan (0.50 g/cm3), Safix plus (0.38 g/cm3). Three days after plaster tile modeling an average specific weight of the tiles was: Gipsan (1.15 g/cm3), Safix plus (1.00 g/cm3), Cellona (1.10 g/cm3). The average humidity of 50% for Safix plus and Cellona plaster tiles was recorded 18 hours after modeling, while for the Gipsan plaster tiles, this humidity value was seen after 48 hours. On the third day after plaster modeling the average humidity of the plaster tiles was 30% for Gipsan, 24% for Safix and 16% for Cellona. Cellona plaster tiles made with 34 °C water achieved the highest elasticity (11.75±3.18 MPa), and Gipsan plaster tiles made with 22 °C had the lowest (7.21±0.9 MPa). Cellona plaster tiles made with 34 °C water showed maximum material strength (4390±838 MPa), and Gipsan plaster tiles made with 22 °C water showed the lowest material strength (771±367 MPa). The rigidity and strength of Cellona and Gipsan plaster are higher in tiles made in warmer water, and for Safix plus are higher in tiles made in cooler water

  16. iCVD Cyclic Polysiloxane and Polysilazane as Nanoscale Thin-Film Electrolyte: Synthesis and Properties.

    PubMed

    Chen, Nan; Reeja-Jayan, B; Liu, Andong; Lau, Jonathan; Dunn, Bruce; Gleason, Karen K

    2016-03-01

    A group of crosslinked cyclic siloxane (SiO) and silazane (SiN) polymers are synthesized via solvent-free initiated chemical vapor deposition (iCVD). Notably, this is the first report of cyclic polysilazanes synthesized via the gas-phase iCVD method. The deposited nanoscale thin films are thermally stable and chemically inert. By iCVD, they can uniformly and conformally cover nonplanar surfaces having complex geometry. Although polysiloxanes are traditionally utilized as dielectric materials and insulators, our research shows these cyclic organosilicon polymers can conduct lithium ions (Li(+) ) at room temperature. The conformal coating and the room temperature ionic conductivity make these cyclic organosilicon polymers attractive for use as thin-film electrolytes in solid-state batteries. Also, their synthesis process and properties have been systemically studied and discussed. PMID:26785633

  17. Preparation and ageing-resistant properties of polyester composites modified with functional nanoscale additives

    NASA Astrophysics Data System (ADS)

    Guo, Gang; Shi, Qiwu; Luo, Yanbing; Fan, Rangrang; Zhou, Liangxue; Qian, Zhiyong; Yu, Jie

    2014-05-01

    This study investigated ageing-resistant properties of carboxyl-terminated polyester (polyethylene glycol terephthalate) composites modified with nanoscale titanium dioxide particles (nano-TiO2). The nano-TiO2 was pretreated by a dry coating method, with aluminate coupling agent as a functional grafting additive. The agglomeration resistance was evaluated, which exhibited significant improvement for the modified nanoparticles. Then, the effects of the modified nano-TiO2 on the crosslinking and ageing-resistant properties of the composites were studied. With a real-time Fourier transform infrared (FT-IR) measurement, the nano-TiO2 displayed promoting effect on the crosslinking of polyester resin with triglycidyl isocyanurate (TGIC) as crosslinking agent. Moreover, the gloss retention, colour aberration and the surface morphologies of the composites during accelerated UV ageing (1500 hours) were investigated. The results demonstrated much less degree of ageing degradation for the nanocomposites, indicating an important role of the nano-TiO2 in improving the ageing-resistant properties of synthetic polymer composites.

  18. Preparation and ageing-resistant properties of polyester composites modified with functional nanoscale additives.

    PubMed

    Guo, Gang; Shi, Qiwu; Luo, Yanbing; Fan, Rangrang; Zhou, Liangxue; Qian, Zhiyong; Yu, Jie

    2014-01-01

    This study investigated ageing-resistant properties of carboxyl-terminated polyester (polyethylene glycol terephthalate) composites modified with nanoscale titanium dioxide particles (nano-TiO2). The nano-TiO2 was pretreated by a dry coating method, with aluminate coupling agent as a functional grafting additive. The agglomeration resistance was evaluated, which exhibited significant improvement for the modified nanoparticles. Then, the effects of the modified nano-TiO2 on the crosslinking and ageing-resistant properties of the composites were studied. With a real-time Fourier transform infrared (FT-IR) measurement, the nano-TiO2 displayed promoting effect on the crosslinking of polyester resin with triglycidyl isocyanurate (TGIC) as crosslinking agent. Moreover, the gloss retention, colour aberration and the surface morphologies of the composites during accelerated UV ageing (1500 hours) were investigated. The results demonstrated much less degree of ageing degradation for the nanocomposites, indicating an important role of the nano-TiO2 in improving the ageing-resistant properties of synthetic polymer composites. PMID:24872802

  19. Harnessing the extracellular bacterial production of nanoscale cobalt ferrite with exploitable magnetic properties.

    PubMed

    Coker, Victoria S; Telling, Neil D; van der Laan, Gerrit; Pattrick, Richard A D; Pearce, Carolyn I; Arenholz, Elke; Tuna, Floriana; Winpenny, Richard E P; Lloyd, Jonathan R

    2009-07-28

    Nanoscale ferrimagnetic particles have a diverse range of uses from directed cancer therapy and drug delivery systems to magnetic recording media and transducers. Such applications require the production of monodisperse nanoparticles with well-controlled size, composition, and magnetic properties. To fabricate these materials purely using synthetic methods is costly in both environmental and economical terms. However, metal-reducing microorganisms offer an untapped resource to produce these materials. Here, the Fe(III)-reducing bacterium Geobacter sulfurreducens is used to synthesize magnetic iron oxide nanoparticles. A combination of electron microscopy, soft X-ray spectroscopy, and magnetometry techniques was employed to show that this method of biosynthesis results in high yields of crystalline nanoparticles with a narrow size distribution and magnetic properties equal to the best chemically synthesized materials. In particular, it is demonstrated here that cobalt ferrite (CoFe(2)O(4)) nanoparticles with low temperature coercivity approaching 8 kOe and an effective anisotropy constant of ∼10(6) erg cm(-3) can be manufactured through this biotechnological route. The dramatic enhancement in the magnetic properties of the nanoparticles by the introduction of high quantities of Co into the spinel structure represents a significant advance over previous biomineralization studies in this area using magnetotactic bacteria. The successful production of nanoparticulate ferrites achieved in this study at high yields could open up the way for the scaled-up industrial manufacture of nanoparticles using environmentally benign methodologies. PMID:19507866

  20. John H. Dillon Medal Talk: Protein Fibrils, Polymer Physics: Encounter at the Nanoscale

    NASA Astrophysics Data System (ADS)

    Mezzenga, Raffaele

    2011-03-01

    Aggregation of proteins is central to many aspects of daily life, ranging from blood coagulation, to eye cataract formation disease, food processing, or neurodegenerative infections. In particular, the physical mechanisms responsible for amyloidosis, the irreversible fibril formation of various proteins implicated in protein misfolding disorders such as Alzheimer, Creutzfeldt-Jakob or Huntington's diseases, have not yet been fully elucidated. In this talk I will discuss how polymer physics and colloidal science concepts can be used to reveal very useful information on the formation, structure and properties of amyloid protein fibrils. I will discuss their physical properties at various length scales, from their collective liquid crystalline behavior in solution to their structural features at the single molecule length scale and show how polymer science notions can shed a new light on these interesting systems. 1) ``Understanding amyloid aggregation by statistical analysis of atomic force microscopy images'' J. Adamcik, J.-M. Jung, J. Flakowski, P. De Los Rios, G. Dietler and R. Mezzenga, Nature nanotechnology, 5, 423 (2010)

  1. Physical properties and mantle dynamics

    SciTech Connect

    Shankland, T.J.; Johnson, P.A.; McCall, K.R.

    1997-11-01

    This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). Because planetary interiors are remote, laboratory methods and associated theory are an essential step for interpreting geophysical measurements in terms of quantities that are needed for understanding Earth--temperature, composition, stress state, history, and hazards. One objective is the study of minerals and rocks as materials using experimental methods; another is to develop new methods, as in high pressure research, codes for computation in rock/soil physics, or nuclear-based analysis. Accomplishments include developing a single-crystal x-ray diffraction apparatus with application to materials at extremely high pressure and temperature; P-V-T equations of state and seismic velocity measurements for understanding the composition of Earth`s outer 1,000 km; creating computational tools to explain complex stress-strain histories of rocks; and measuring tungsten/thorium ratios W/Th that agree with the hypothesis that Earth accreted heterogeneously. Work performed in this project applies to geosciences, geothermal energy, mineral and rock properties, seismic detection, and isotope dating.

  2. On physical nanoscale aspects of compatibility of steels with hydrogen and natural gas.

    PubMed

    Nechaev, Yu S; Ochsner, A

    2010-02-01

    The possibilities of effective solutions of relevant technological problems are considered based on the analysis of fundamental physical aspects, elucidation of the nano-structural mechanisms and interrelations of aging and hydrogen embrittlement of materials (steels) in the hydrogen industry and gas-main industries. The adverse effects which these mechanisms and processes have on the service properties and technological lifetime of materials are analyzed. The concomitant fundamental process of formation of carbohydride-like and other segregation nanostructures at dislocations (with the segregation capacity 1 to 1.5 orders of magnitude greater than in the widely used Cottrell 'atmosphere' model) and grain boundaries is discussed in the context of how these nanostructures affect technological processes (aging, hydrogen embrittlement, stress corrosion damage, and failure) and the physicomechanical properties of the metallic materials (including the technological lifetimes of pipeline steels). PMID:20352806

  3. Electrical and Optical Properties of CeNi5 Nanoscale Films.

    PubMed

    Todoran, Radu; Todoran, Daniela; Racolta, Dania; Szakács, Zsolt

    2016-12-01

    Rare earth compounds are interesting from both a theoretical point of view and for their applications. That is the reason why determining their optical and electrical properties deserves special attention. In this article, we present the conditions we obtained homogenous CeNi5 thin films of nanometer thicknesses. To achieve this goal, our method of choice was laser-induced vaporization, using short and modulated impulses, with electro-optical tuning for the quality factor. The layers that were deposited at a single laser burst had thicknesses between 1.5 and 2.5 nm, depending on the geometry of the experimental setup.Structural and compositional studies of the nanoscale films were made using XRD. The temperature dependence of electrical conductivity was also determined. The following optical properties of the specimens were computed using the Kramers-Krönig framework and discussed: absolute reflection and transmission coefficients for a single wavelength and relative ones for the wide UV-VIS-IR spectra, spectral dependence of the refractive index, and extinction coefficient as real and imaginary parts of the complex refractive index. The valence band studies were made with X-ray photoelectron spectroscopy. All these determinations were well correlated and permitted the evaluation of the energy densities of states in the deeper bands, near the Fermi energy, and at the surface states. PMID:27184966

  4. Nanoscale friction and wear properties of silicon wafer under different lubrication conditions

    NASA Astrophysics Data System (ADS)

    Chen, Xiaochun; Zhao, Yongwu; Wang, Yongguang; Zhou, Hailan; Ni, Zhifeng; An, Wei

    2013-10-01

    The nanoscale friction and wear properties of single crystal silicon wafer under different lubrication conditions are studied in this paper. The experiments were performed with Si3N4 ball sliding on the surface of silicon wafer under four different lubrication conditions: dry friction, water lubrication, hydrogen peroxide lubrication and the static hydrogen peroxide dry friction. The results from the experiments have been analyzed showing the different friction and wear properties of the silicon wafer in different lubrication conditions. It is concluded that the wear rates under the water lubrication and under the hydrogen peroxide lubrication are both small, the chemical reactions are facilitated by the mechanical processes when the load and the sliding speed reach certain levels. This is mainly resulted by the enhanced lubricant performance with the formed silicon hydroxide Si(OH)4 film. Under the water lubrication, the wear is found in a way of material removed in molecule scale. Under the hydrogen peroxide lubrication, the wear is mainly caused by the spalling of micro-cracks. Under the dry friction condition, the wear is found being adhesive wear. And under the static peroxide dry friction, the wear is prevailing adhesive wear. These results are essential and valuable to the development of the efficient and environmental-friendly slurry for the chemical mechanical polishing (CMP) process.

  5. Correlation of nanoscale structure with electronic and magnetic properties in semiconductor materials

    NASA Astrophysics Data System (ADS)

    He, Li

    , with ferromagnetism/paramagnetism transition temperature in the range of 20-200 K. The magnetic properties of 300-350°C implanted Ge:Mn (which produced crystalline Ge films) varied significantly with implantation dose and annealing condition due to precipitation and phase transformation of MnxGe1-x secondary phase particles, Mn5Ge3, Mn11Ge8 and Mn5Ge2 (zeta). The third part of this work aimed at design of a new experimental method to correlate the structure and energy levels of individual quantum dots (QD) by combining TEM and ballistic electron emission spectroscopy (BEES). A p-type delta doping layer to flatten the QD energy band (otherwise, the Schottky barrier at the BEES metal base/n-type semiconductor interface causes band bending), and an etch-stop layer to prevent etching holes in TEM samples was included in the QD sample structure. TEM analysis found QDs to be of cone shape with the base diameter ranging from about 10 to 50 nm. Preliminary BEES characterization on a sample without QD marks detected a QD energy level 0.12 eV below the In0.5Al0.3Ga0.2P matrix layer conduction band. Micron- and nanometer-scale marks were fabricated by FIB milling and TEM electron beam induced carbon deposition, respectively, to index individual QDs so that TEM and BEES characterization could be performed on the same QDs in the future. Overall, this work explored different semiconductor nanostructures with the broad goal of correlation of nanoscale structure with electronic and magnetic properties. The originality of this research lies in the design and performance of novel experimental methods, and the improved understanding of structure-property relationships at the nanoscale.

  6. Nanoscale biophysical properties of the cell surface galactosaminogalactan from the fungal pathogen Aspergillus fumigatus

    NASA Astrophysics Data System (ADS)

    Beaussart, Audrey; El-Kirat-Chatel, Sofiane; Fontaine, Thierry; Latgé, Jean-Paul; Dufrêne, Yves F.

    2015-09-01

    Many fungal pathogens produce cell surface polysaccharides that play essential roles in host-pathogen interactions. In Aspergillus fumigatus, the newly discovered polysaccharide galactosaminogalactan (GAG) mediates adherence to a variety of substrates through molecular mechanisms that are poorly understood. Here we use atomic force microscopy to unravel the localization and adhesion of GAG on living fungal cells. Using single-molecule imaging with tips bearing anti-GAG antibodies, we found that GAG is massively exposed on wild-type (WT) germ tubes, consistent with the notion that this glycopolymer is secreted by the mycelium of A. fumigatus, while it is lacking on WT resting conidia and on germ tubes from a mutant (Δuge3) deficient in GAG. Imaging germ tubes with tips bearing anti-β-glucan antibodies shows that exposure of β-glucan is strongly increased in the Δuge3 mutant, indicating that this polysaccharide is masked by GAG during hyphal growth. Single-cell force measurements show that expression of GAG on germ tubes promotes specific adhesion to pneumocytes and non-specific adhesion to hydrophobic substrates. These results provide a molecular foundation for the multifunctional adhesion properties of GAG, thus suggesting it could be used as a potential target in anti-adhesion therapy and immunotherapy. Our methodology represents a powerful approach for characterizing the nanoscale organization and adhesion of cell wall polysaccharides during fungal morphogenesis, thereby contributing to increase our understanding of their role in biofilm formation and immune responses.

  7. Nanoscale characterization and magnetic property of NiCoCu/Cu multilayer nanowires

    NASA Astrophysics Data System (ADS)

    Qi, Kuo; Li, Xinghua; Zhang, Hong; Wang, Li; Xue, Desheng; Zhang, Haoli; Zhou, Baofan; Mellors, Nigel J.; Peng, Yong

    2012-12-01

    NiCo/Cu multilayer nanowires have been successfully fabricated by a pulse electrodeposition technique using anodic aluminum oxide templates, and their chemistry, crystal structure and magnetic properties characterized at the nanoscale. It was found that each individual nanowire had a regular periodic structure. The NiCo/Cu nanowires also displayed a continuous morphology, smooth surface and polycrystalline fcc structure. EDX elemental mappings confirmed the presence of nickel, cobalt and copper, which appear clearly with a periodic distribution throughout the samples. Both the NiCo and Cu layers were polycrystalline and the average length of the interlayers between NiCo and Cu layers was approximately 3-4 nm. The NiCo/Cu nanowire arrays had an easy axis parallel to the length of wire and exhibited a curling magnetization reversal mechanism. This study highlights the basis morphological, structural and chemical information for NiCoCu/Cu multilayer nanowires, which is critical for their applications in nanodevices and nanoelectronics.

  8. Innovative pharmaceutical development based on unique properties of nanoscale delivery formulation

    PubMed Central

    Mozhi, Anbu; Zhang, Xu; Zhao, Yuanyuan; Xue, Xiangdong; Hao, Yanli; Zhang, Xiaoning; Wang, Paul C.; Liang, Xing-Jie

    2014-01-01

    The advent of nanotechnology has reignited interest in the field of pharmaceutical science for the development of nanomedicine. Nanomedicinal formulations are nanometer-sized carrier materials designed for increasing the drug tissue bioavailability, thereby improving the treatment of systemically applied chemotherapeutic drugs. Nanomedicine is a new approach to deliver the pharmaceuticals through different routes of administration with safer and more effective therapies compared to conventional methods. To date, various kinds of nanomaterials have been developed over the years to make delivery systems more effective for the treatment of various diseases. Even though nanomaterials have significant advantages due to their unique nanoscale properties, there are still significant challenges in the improvement and development of nanoformulations with composites and other materials. Here in this review, we highlight the nanomedicinal formulations aiming to improve the balance between the efficacy and the toxicity of therapeutic interventions through different routes of administration and how to design nanomedicine for safer and more effective ways to improve the treatment quality. We also emphasize the environmental and health prospects of nanomaterials for human health care. PMID:23860639

  9. Innovative pharmaceutical development based on unique properties of nanoscale delivery formulation

    NASA Astrophysics Data System (ADS)

    Kumar, Anil; Chen, Fei; Mozhi, Anbu; Zhang, Xu; Zhao, Yuanyuan; Xue, Xiangdong; Hao, Yanli; Zhang, Xiaoning; Wang, Paul C.; Liang, Xing-Jie

    2013-08-01

    The advent of nanotechnology has reignited interest in the field of pharmaceutical science for the development of nanomedicine. Nanomedicinal formulations are nanometer-sized carrier materials designed for increasing the drug tissue bioavailability, thereby improving the treatment of systemically applied chemotherapeutic drugs. Nanomedicine is a new approach to deliver the pharmaceuticals through different routes of administration with safer and more effective therapies compared to conventional methods. To date, various kinds of nanomaterials have been developed over the years to make delivery systems more effective for the treatment of various diseases. Even though nanomaterials have significant advantages due to their unique nanoscale properties, there are still significant challenges in the improvement and development of nanoformulations with composites and other materials. Here in this review, we highlight the nanomedicinal formulations aiming to improve the balance between the efficacy and the toxicity of therapeutic interventions through different routes of administration and how to design nanomedicine for safer and more effective ways to improve the treatment quality. We also emphasize the environmental and health prospects of nanomaterials for human health care.

  10. Nanoscale Wicking

    NASA Astrophysics Data System (ADS)

    Zhou, Jijie; Sansom, Elijah; Gharib, Mory; Noca, Flavio

    2003-11-01

    A wick is a bundle of fibers that by capillary attraction draws up to be burned a steady supply of the oil in lamps. In textile research, wicking is the process by which liquids are transported across or along fibers by capillary action (of relevance to perspiration). A similar phenomenon was recently discovered in our lab with mats of nanoscale fibers. A droplet containing a surfactant solution was placed on top of a well-aligned mat of carbon nanotubes: wicking was then observed as a film of liquid propagating within the nanocarpet, such as a stain or drop absorbed into a textile fabric. The nanoscale wicking process in carbon nano-arrays offers a simple and enabling technology for the processing (transport, mixing, filtering) of picoliters of fluids without any need for confinement (nanochannel) or bulky driving pressure apparatus. In this work, nanoscale wicking properties are quantified as a function of surfactant activity and carbon nanoarray geometry. The biomolecular sieving capability of the nanotube arrays is also put to test by the addition of biomolecules, while using the wicking process as the fluid driving force.

  11. Lorentz contact resonance spectroscopy for nanoscale characterisation of structural and mechanical properties of biological, dental and pharmaceutical materials.

    PubMed

    Khanal, Dipesh; Dillon, Eoghan; Hau, Herman; Fu, Dong; Ramzan, Iqbal; Chrzanowski, Wojciech

    2015-12-01

    Scanning probe microscopy has been widely used to obtain topographical information and to quantify nanostructural properties of different materials. Qualitative and quantitative imaging is of particular interest to study material-material interactions and map surface properties on a nanoscale (i.e. stiffness and viscoelastic properties). These data are essential for the development of new biomedical materials. Currently, there are limited options to map viscoelastic properties of materials at nanoscale and at high resolutions. Lorentz contact resonance (LCR) is an emerging technique, which allows mapping viscoelasticity of samples with stiffness ranging from a few hundred Pa up to several GPa. Here we demonstrate the applicability of LCR to probe and map the viscoelasticity and stiffness of 'soft' (biological sample: cell treated with nanodiamond), 'medium hard' (pharmaceutical sample: pMDI canister) and 'hard' (human teeth enamel) specimens. The results allowed the identification of nanodiamond on the cells and the qualitative assessment of its distribution based on its nanomechanical properties. It also enabled mapping of the mechanical properties of the cell to demonstrate variability of these characteristics in a single cell. Qualitative imaging of an enamel sample demonstrated variations of stiffness across the specimen and precise identification of enamel prisms (higher stiffness) and enamel interrods (lower stiffness). Similarly, mapping of the pMDI canister wall showed that drug particles were adsorbed to the wall. These particles showed differences in stiffness at nanoscale, which suggested variations in surface composition-multiphasic material. LCR technique emerges as a valuable tool for probing viscoelasticity of samples of varying stiffness's. PMID:26518012

  12. Material properties and applications of blended organic thin films with nanoscale domains deposited by RIR-MAPLE

    NASA Astrophysics Data System (ADS)

    Stiff-Roberts, Adrienne D.; McCormick, Ryan D.; Ge, Wangyao

    2015-03-01

    Resonant-infrared, matrix-assisted pulsed laser evaporation (RIR-MAPLE) has been used to deposit blended, organic thin-films with nanoscale domain sizes of constituent polymers, small molecules, or colloidal nanoparticles. In the emulsion-based RIR-MAPLE process, the target contains a nonpolar, organic solvent phase and a polar, water phase. The emulsion properties have a direct impact on the nanoscale morphology of single-component organic thin films, while the morphology of blended, organic thin films also depends on the RIR-MAPLE deposition mode. In addition to these fundamental aspects, applications of blended organic films (organic solar cells, anti-reflection coatings, and multi-functional surfaces) deposited by emulsion-based RIR-MAPLE are presented. Importantly, domain sizes in the blended films are critical to thin-film functionality.

  13. Nanoscale Properties of Rocks and Subduction Zone Rheology: Inferences for the Mechanisms of Deep Earthquakes

    NASA Astrophysics Data System (ADS)

    Riedel, M. R.

    2007-12-01

    Grain boundaries are the key for the understanding of mineral reaction kinetics. More generally, nanometer scale processes involved in breaking and establishing bonds at reaction sites determine how and at which rate bulk rock properties change in response to external tectonic forcing and possibly feed back into various geodynamic processes. A particular problem is the effects of grain-boundary energy on the kinetics of the olivine-spinel phase transformation in subducting slabs. Slab rheology is affected in many ways by this (metastable) mineral phase change. Sluggish kinetics due to metastable hindrance is likely to cause particular difficulties, because of possible strong non-linear feedback loops between strain-rate and change of creep properties during transformation. In order to get these nanoscale properties included into thermo-mechanical models, reliable kinetic data is required. The measurement of grain-boundary energies is, however, a rather difficult problem. Conventional methods of grain boundary surface tension measurement include (a) equilibrium angles at triple junction (b) rotating ball method (c) thermal groove method, and others (Gottstein & Shvindlerman, 1999). Here I suggest a new method that allows for the derivation of grain-boundary energies for an isochemical phase transformation based on experimental (in-situ) kinetic data in combination with a corresponding dynamic scaling law (Riedel and Karato, 1997). The application of this method to the olivine-spinel phase transformation in subducting slabs provides a solution to the extrapolation problem of measured kinetic data: Any kinetic phase boundary measured at the laboratory time scale can be "scaled" to the correct critical isotherm at subduction zones, under experimentelly "forbidden" conditions (Liou et al., 2000). Consequences for the metastability hypothesis that relates deep seismicity with olivine metastability are derived and discussed. References: Gottstein G, Shvindlerman LS (1999

  14. Physical properties of cumin and caraway seeds

    NASA Astrophysics Data System (ADS)

    Zare, D.; Bakhshipour, A.; Chen, G.

    2013-12-01

    Physical properties of cumin and caraway seeds were measured and compared at constant moisture content of 7.5% w.b. The average thousand mass of grain, mean length, mean width, mean thickness, equivalent diameter, geometric mean diameter, surface area, volume, sphericity, aspect ratio, true density, bulk density and porosity were measured for cumin and caraway. There are significant differences (p<0.01) in most physical properties of cumin and caraway, except porosity and sphericity

  15. Physical properties of immiscible polymers

    NASA Technical Reports Server (NTRS)

    Harris, J. Milton

    1987-01-01

    The demixing of immiscible polymers in low gravity is discussed. Applications of knowledge gained in this research will provide a better understanding of the role of phase segregation in determining the properties of polymer blends made from immiscible polymers. Knowledge will also be gained regarding the purification of biological materials by partitioning between the two liquid phases formed by solution of the polymers polyethylene glycol and dextran in water. Testing of new apparatus for space flight, extension of affinity phase partitioning, refinement of polymer chemistry, and demixing of isopycnic polymer phases in a one gravity environment are discussed.

  16. The trinucleons: Physical observables and model properties

    SciTech Connect

    Gibson, B.F.

    1992-05-01

    Our progress in understanding the properties of {sup 3}H and {sup 3}He in terms of a nonrelativistic Hamiltonian picture employing realistic nuclear forces is reviewed. Trinucleon model properties are summarized for a number of contemporary force models, and predictions for physical observables are presented. Disagreement between theoretical model results and experimental results are highlighted.

  17. The trinucleons: Physical observables and model properties

    SciTech Connect

    Gibson, B.F.

    1992-01-01

    Our progress in understanding the properties of {sup 3}H and {sup 3}He in terms of a nonrelativistic Hamiltonian picture employing realistic nuclear forces is reviewed. Trinucleon model properties are summarized for a number of contemporary force models, and predictions for physical observables are presented. Disagreement between theoretical model results and experimental results are highlighted.

  18. Harnessing microbial subsurface metal reduction activities to synthesise nanoscale cobalt ferrite with enhanced magnetic properties

    SciTech Connect

    Coker, Victoria S.; Telling, Neil D.; van der Laan, Gerrit; Pattrick, Richard A.D.; Pearce, Carolyn I.; Arenholz, Elke; Tuna, Floriana; Winpenny, Richard E.P.; Lloyd, Jonathan R.

    2009-03-24

    Nanoscale ferrimagnetic particles have a diverse range of uses from directed cancer therapy and drug delivery systems to magnetic recording media and transducers. Such applications require the production of monodisperse nanoparticles with well-controlled size, composition, and magnetic properties. To fabricate these materials purely using synthetic methods is costly in both environmental and economical terms. However, metal-reducing microorganisms offer an untapped resource to produce these materials. Here, the Fe(III)-reducing bacterium Geobacter sulfurreducens is used to synthesize magnetic iron oxide nanoparticles. A combination of electron microscopy, soft X-ray spectroscopy, and magnetometry techniques was employed to show that this method of biosynthesis results in high yields of crystalline nanoparticles with a narrow size distribution and magnetic properties equal to the best chemically synthesized materials. In particular, it is demonstrated here that cobalt ferrite (CoFe{sub 2}O{sub 4}) nanoparticles with low temperature coercivity approaching 8 kOe and an effective anisotropy constant of {approx} 10{sup 6} erg cm{sup -3} can be manufactured through this biotechnological route. The dramatic enhancement in the magnetic properties of the nanoparticles by the introduction of high quantities of Co into the spinel structure represents a significant advance over previous biomineralization studies in this area using magnetotactic bacteria. The successful production of nanoparticulate ferrites achieved in this study at high yields could open up the way for the scaled-up industrial manufacture of nanoparticles using environmentally benign methodologies. Production of ferromagnetic nanoparticles for pioneering cancer therapy, drug delivery, chemical sensors, catalytic activity, photoconductive materials, as well as more traditional uses in data storage embodies a large area of inorganic synthesis research. In particular, the addition of transition metals other than

  19. Structure and physical properties of silkworm cocoons

    PubMed Central

    Chen, Fujia; Porter, David; Vollrath, Fritz

    2012-01-01

    Silkworm cocoons have evolved a wide range of different structures and combinations of physical and chemical properties in order to cope with different threats and environmental conditions. We present our observations and measurements on 25 diverse types of cocoons in a first attempt to correlate physical properties with the structure and morphology of the cocoons. These two architectural parameters appear to be far more important than the material properties of the silk fibres themselves. We consider tensile and compressive mechanical properties and gas permeation of the cocoon walls, and in each case identify mechanisms or models that relate these properties to cocoon structure, usually based upon non-woven fibre composites. These properties are of relevance also for synthetic non-woven composite materials and our studies will help formulate bio-inspired design principles for new materials. PMID:22552916

  20. Physical Properties of Centaur Objects

    NASA Technical Reports Server (NTRS)

    Cruikshank, Dale P.; DeVincenzi, Donald L. (Technical Monitor)

    2001-01-01

    Centaurs are objects in unstable orbits that cross the orbits of the giant planets. They are presumed to be recent additions to the planetary zone of the Solar System, having been dynamically perturbed from the Kulper Disk by the gravitational action of Neptune. Telescopic observations of Centaurs are important because they give us a view of the composition (and in some cases cometary activity) of large bodies that are normally to far from the Sun to be studied in detail. This paper reports on physical observations, primarily through spectroscopy, of the compositions of a small number of Centaurs that have been studied to date. In particular, the composition of 5145 Pholus is reviewed, following the published work of Crulkshank et al., in which compositional models that fit the spectrum well included H2O ice, the organic solid Titan tholin, a light hydrocarbon ice (e.g., CH3OH), the silicate mineral olivine, and amorphous carbon. The Centaur 1997 CU(26) shows evidence for H2O ice, but nothing else is yet identified.

  1. Characterizing Nanoscale Transient Communication.

    PubMed

    Chen, Yifan; Anwar, Putri Santi; Huang, Limin; Asvial, Muhamad

    2016-04-01

    We consider the novel paradigm of nanoscale transient communication (NTC), where certain components of the small-scale communication link are physically transient. As such, the transmitter and the receiver may change their properties over a prescribed lifespan due to their time-varying structures. The NTC systems may find important applications in the biomedical, environmental, and military fields, where system degradability allows for benign integration into life and environment. In this paper, we analyze the NTC systems from the channel-modeling and capacity-analysis perspectives and focus on the stochastically meaningful slow transience scenario, where the coherence time of degeneration Td is much longer than the coding delay Tc. We first develop novel and parsimonious models to characterize the NTC channels, where three types of physical layers are considered: electromagnetism-based terahertz (THz) communication, diffusion-based molecular communication (DMC), and nanobots-assisted touchable communication (TouchCom). We then revisit the classical performance measure of ϵ-outage channel capacity and take a fresh look at its formulations in the NTC context. Next, we present the notion of capacity degeneration profile (CDP), which describes the reduction of channel capacity with respect to the degeneration time. Finally, we provide numerical examples to demonstrate the features of CDP. To the best of our knowledge, the current work represents a first attempt to systematically evaluate the quality of nanoscale communication systems deteriorating with time. PMID:26955048

  2. Physical Properties of Gas Hydrates: A Review

    DOE PAGESBeta

    Gabitto, Jorge F.; Tsouris, Costas

    2010-01-01

    Memore » thane gas hydrates in sediments have been studied by several investigators as a possible future energy resource. Recent hydrate reserves have been estimated at approximately 10 16   m 3 of methane gas worldwide at standard temperature and pressure conditions. In situ dissociation of natural gas hydrate is necessary in order to commercially exploit the resource from the natural-gas-hydrate-bearing sediment. The presence of gas hydrates in sediments dramatically alters some of the normal physical properties of the sediment. These changes can be detected by field measurements and by down-hole logs. An understanding of the physical properties of hydrate-bearing sediments is necessary for interpretation of geophysical data collected in field settings, borehole, and slope stability analyses; reservoir simulation; and production models. This work reviews information available in literature related to the physical properties of sediments containing gas hydrates. A brief review of the physical properties of bulk gas hydrates is included. Detection methods, morphology, and relevant physical properties of gas-hydrate-bearing sediments are also discussed.« less

  3. Physical Properties of Gas Hydrates: A Review

    SciTech Connect

    Gabitto, Jorge; Tsouris, Costas

    2010-01-01

    Methane gas hydrates in sediments have been studied by several investigators as a possible future energy resource. Recent hydrate reserves have been estimated at approximately 1016?m3 of methane gas worldwide at standard temperature and pressure conditions. In situ dissociation of natural gas hydrate is necessary in order to commercially exploit the resource from the natural-gas-hydrate-bearing sediment. The presence of gas hydrates in sediments dramatically alters some of the normal physical properties of the sediment. These changes can be detected by field measurements and by down-hole logs. An understanding of the physical properties of hydrate-bearing sediments is necessary for interpretation of geophysical data collected in field settings, borehole, and slope stability analyses; reservoir simulation; and production models. This work reviews information available in literature related to the physical properties of sediments containing gas hydrates. A brief review of the physical properties of bulk gas hydrates is included. Detection methods, morphology, and relevant physical properties of gas-hydrate-bearing sediments are also discussed.

  4. Exploring Nanoscale Electrical Properties of CuO-Graphene Based Hybrid Interfaced Memory Device by Conductive Atomic Force Microscopy.

    PubMed

    Singh, Bharti; Mehta, B R; Varandani, Deepak; Savu, Andreea Veronica; Brugger, Juergen

    2016-04-01

    The phenomenon of resistive switching is based on nanoscale changes in the electrical properties of the interface. In the present study, conductive atomic force microscope based nanoscale measurements of copper oxide (CuO-multilayer graphene (MLG) hybrid interface based devices have been carried out to understand changes in the electrical properties during resistive switching of the Ti-CuO/MLG-Cu memory cells having different dimensions fabricated on the same substrate using stencil lithography technique. The dependence of resistive switching characteristics in LRS and HRS and current level of the conductive filaments (CF) on the electrode area have been studied. As the device dimension is reduced, the filamentary contribution is enhanced in comparison to the background contribution, resulting in'an increase in the current density ratio between LRS and HRS. It is also observed that as the device dimension is decreased from 150 to 25 µm, the filament size decreases from 95 nm to 20 nm, respectively, which causes a decrease in the reset current and reset voltage. The results of the nanoscale CAFM measurements have shown a good correlation with the switching parameters obtained by the macroscale pad I-V measurements, thereby, suggesting the origin of resistive switching is due to the formation and rupture of an entity called filament, whose dimension is in nanorange. It is observed that changes in the electrical properties of the overall interface layer along with changes in the electrical conductivity of these filaments contribute towards resistive switching phenomenon. This study suggests that a significant reduction of reset current can be achieved by decreasing the memory device dimensions. PMID:27451764

  5. Physical and chemical properties of refrigeration lubricants

    SciTech Connect

    Sunami, Motoshi

    1999-07-01

    The physical and chemical properties of refrigeration lubricants are discussed. Although much attention has been focused on the performance of candidate lubricants for use with hydrofluorocarbons (HFCs) in order to obtain satisfactory lubrication performance in compressors, the properties of the lubricants themselves have not been well discussed. In this paper, the properties of refrigeration lube base stocks and of lube-refrigerant mixtures are described, specifically the viscosity, density, and refrigerant solubility, the change in viscosity and density due to solution with HFCs, and the insulation properties of the base stocks and the refrigerant mixture.

  6. Microscale and nanoscale hierarchical structured mesh films with superhydrophobic and superoleophilic properties induced by long-chain fatty acids

    NASA Astrophysics Data System (ADS)

    Wang, Shutao; Song, Yanlin; Jiang, Lei

    2007-01-01

    Inspired by the lotus effect, we fabricate new microscale and nanoscale hierarchical structured copper mesh films by a simple electrochemical deposition. After modification of the long-chain fatty acid monolayer, these films show superhydrophobic and superoleophilic properties, which could be used for the effective separation of oil and water. The length of the fatty acid chain strongly influences the surface wettability of as-prepared films. It is confirmed that the cooperative effect of the hierarchical structure of the copper film and the nature of the long-chain fatty acid contribute to this unique surface wettability.

  7. Dynamic molecular crystals with switchable physical properties.

    PubMed

    Sato, Osamu

    2016-06-21

    The development of molecular materials whose physical properties can be controlled by external stimuli - such as light, electric field, temperature, and pressure - has recently attracted much attention owing to their potential applications in molecular devices. There are a number of ways to alter the physical properties of crystalline materials. These include the modulation of the spin and redox states of the crystal's components, or the incorporation within the crystalline lattice of tunable molecules that exhibit stimuli-induced changes in their molecular structure. A switching behaviour can also be induced by changing the molecular orientation of the crystal's components, even in cases where the overall molecular structure is not affected. Controlling intermolecular interactions within a molecular material is also an effective tool to modulate its physical properties. This Review discusses recent advances in the development of such stimuli-responsive, switchable crystalline compounds - referred to here as dynamic molecular crystals - and suggests how different approaches can serve to prepare functional materials. PMID:27325090

  8. Aerosol physical properties from satellite horizon inversion

    NASA Technical Reports Server (NTRS)

    Gray, C. R.; Malchow, H. L.; Merritt, D. C.; Var, R. E.; Whitney, C. K.

    1973-01-01

    The feasibility is investigated of determining the physical properties of aerosols globally in the altitude region of 10 to 100 km from a satellite horizon scanning experiment. The investigation utilizes a horizon inversion technique previously developed and extended. Aerosol physical properties such as number density, size distribution, and the real and imaginary components of the index of refraction are demonstrated to be invertible in the aerosol size ranges (0.01-0.1 microns), (0.1-1.0 microns), (1.0-10 microns). Extensions of previously developed radiative transfer models and recursive inversion algorithms are displayed.

  9. Physical properties of cytoplasmic intermediate filaments.

    PubMed

    Block, Johanna; Schroeder, Viktor; Pawelzyk, Paul; Willenbacher, Norbert; Köster, Sarah

    2015-11-01

    Intermediate filaments (IFs) constitute a sophisticated filament system in the cytoplasm of eukaryotes. They form bundles and networks with adapted viscoelastic properties and are strongly interconnected with the other filament types, microfilaments and microtubules. IFs are cell type specific and apart from biochemical functions, they act as mechanical entities to provide stability and resilience to cells and tissues. We review the physical properties of these abundant structural proteins including both in vitro studies and cell experiments. IFs are hierarchical structures and their physical properties seem to a large part be encoded in the very specific architecture of the biopolymers. Thus, we begin our review by presenting the assembly mechanism, followed by the mechanical properties of individual filaments, network and structure formation due to electrostatic interactions, and eventually the mechanics of in vitro and cellular networks. This article is part of a Special Issue entitled: Mechanobiology. PMID:25975455

  10. Physical Properties of Cometary Nucleus Candidates

    NASA Technical Reports Server (NTRS)

    Jewitt, David; Hillman, John (Technical Monitor)

    2003-01-01

    In this proposal we aim to study the physical properties of the Centaurs and the dead comets, these being the precursors to, and the remnants from, the active cometary nuclei. The nuclei themselves are very difficult to study, because of the contaminating effects of near-nucleus coma. Systematic investigation of the nuclei both before they enter the zone of strong sublimation and after they have depleted their near-surface volatiles should neatly bracket the properties of these objects, revealing evolutionary effects.

  11. Correlation between growth kinetics and nanoscale resistive switching properties of SrTiO3 thin films

    NASA Astrophysics Data System (ADS)

    Muenstermann, Ruth; Menke, Tobias; Dittmann, Regina; Mi, Shaobo; Jia, Chun-Lin; Park, Daesung; Mayer, Joachim

    2010-12-01

    We deliberately fabricated SrTiO3 thin films deviating from ideal stoichiometry and from two-dimensional layer-by-layer growth mode, in order to study the impact of well pronounced defect arrangements on the nanoscale electrical properties. By combining transmission electron microscopy with conductive-tip atomic force microscopy we succeeded to elucidate the microstructure of thin films grown by pulsed laser deposition under kinetically limited growth conditions and to correlate it with the local electrical properties. SrTiO3 thin films, grown in a layer-by-layer growth mode, exhibit a defect structure and conductivity pattern close to single crystals, containing irregularly distributed, resistive switching spots. In contrast to this, Ti-rich films exhibit short-range-ordered, well-conducting resistive switching units. For Ti-rich films grown in a kinetically more restricted island growth mode, we succeeded to identify defective island boundaries with the location of tip-induced resistive switching. The observed nanoscale switching behavior is consistent with a voltage driven oxygen vacancy movement that induces a local redox-based metal-to-insulator transition. Switching occurs preferentially in defect-rich regions, that exhibit a high concentration of oxygen vacancies and might act as easy-diffusion-channels.

  12. Physical and Dynamical Properties of Asteroid Families

    NASA Astrophysics Data System (ADS)

    Zappalà, V.; Cellino, A.; dell'Oro, A.; Paolicchi, P.

    2002-03-01

    The availability of a number of statistically reliable asteroid families and the independent confirmation of their likely collisional origin from dedicated spectroscopic campaigns has been a major breakthrough, making it possible to develop detailed studies of the physical properties of these groupings. Having been produced in energetic collisional events, families are an invaluable source of information on the physics governing these phenomena. In particular, they provide information about the size distribution of the fragments, and on the overall properties of the original ejection velocity fields. Important results have been obtained during the last 10 years on these subjects, with important implications for the general understanding of the collisional history of the asteroid main belt, and the origin of near-Earth asteroids. Some important problems have been raised from these studies and are currently debated. In particular, it has been difficult so far to reconcile the inferred properties of family-forming events with current understanding of the physics of catastrophic collisional breakup. Moreover, the contribution of families to the overall asteroid inventory, mainly at small sizes, is currently controversial. Recent investigations are also aimed at understanding which kind of dynamical evolution might have affected family members since the time of their formation. In addition to potential consequences on the interpretation of current data, there is some speculative possibility of obtaining some estimate of the ages of these groupings. Physical characterization of families will likely represent a prerequisite for further advancement in understanding the properties and history of the asteroid population.

  13. Reconstruction of explicit structural properties at the nanoscale via spectroscopic microscopy

    NASA Astrophysics Data System (ADS)

    Cherkezyan, Lusik; Zhang, Di; Subramanian, Hariharan; Taflove, Allen; Backman, Vadim

    2016-02-01

    The spectrum registered by a reflected-light bright-field spectroscopic microscope (SM) can quantify the microscopically indiscernible, deeply subdiffractional length scales within samples such as biological cells and tissues. Nevertheless, quantification of biological specimens via any optical measures most often reveals ambiguous information about the specific structural properties within the studied samples. Thus, optical quantification remains nonintuitive to users from the diverse fields of technique application. In this work, we demonstrate that the SM signal can be analyzed to reconstruct explicit physical measures of internal structure within label-free, weakly scattering samples: characteristic length scale and the amplitude of spatial refractive-index (RI) fluctuations. We present and validate the reconstruction algorithm via finite-difference time-domain solutions of Maxwell's equations on an example of exponential spatial correlation of RI. We apply the validated algorithm to experimentally measure structural properties within isolated cells from two genetic variants of HT29 colon cancer cell line as well as within a prostate tissue biopsy section. The presented methodology can lead to the development of novel biophotonics techniques that create two-dimensional maps of explicit structural properties within biomaterials: the characteristic size of macromolecular complexes and the variance of local mass density.

  14. Reconstruction of explicit structural properties at the nanoscale via spectroscopic microscopy.

    PubMed

    Cherkezyan, Lusik; Zhang, Di; Subramanian, Hariharan; Taflove, Allen; Backman, Vadim

    2016-02-01

    The spectrum registered by a reflected-light bright-field spectroscopic microscope (SM) can quantify the microscopically indiscernible, deeply subdiffractional length scales within samples such as biological cells and tissues. Nevertheless, quantification of biological specimens via any optical measures most often reveals ambiguous information about the specific structural properties within the studied samples. Thus, optical quantification remains nonintuitive to users from the diverse fields of technique application. In this work, we demonstrate that the SM signal can be analyzed to reconstruct explicit physical measures of internal structure within label-free, weakly scattering samples: characteristic length scale and the amplitude of spatial refractive-index (RI) fluctuations. We present and validate the reconstruction algorithm via finite-difference time-domain solutions of Maxwell's equations on an example of exponential spatial correlation of RI. We apply the validated algorithm to experimentally measure structural properties within isolated cells from two genetic variants of HT29 colon cancer cell line as well as within a prostate tissue biopsy section. The presented methodology can lead to the development of novel biophotonics techniques that create two-dimensional maps of explicit structural properties within biomaterials: the characteristic size of macromolecular complexes and the variance of local mass density. PMID:26886803

  15. Waste Feed Evaporation Physical Properties Modeling

    SciTech Connect

    Daniel, W.E.

    2003-08-25

    This document describes the waste feed evaporator modeling work done in the Waste Feed Evaporation and Physical Properties Modeling test specification and in support of the Hanford River Protection Project (RPP) Waste Treatment Plant (WTP) project. A private database (ZEOLITE) was developed and used in this work in order to include the behavior of aluminosilicates such a NAS-gel in the OLI/ESP simulations, in addition to the development of the mathematical models. Mathematical models were developed that describe certain physical properties in the Hanford RPP-WTP waste feed evaporator process (FEP). In particular, models were developed for the feed stream to the first ultra-filtration step characterizing its heat capacity, thermal conductivity, and viscosity, as well as the density of the evaporator contents. The scope of the task was expanded to include the volume reduction factor across the waste feed evaporator (total evaporator feed volume/evaporator bottoms volume). All the physical properties were modeled as functions of the waste feed composition, temperature, and the high level waste recycle volumetric flow rate relative to that of the waste feed. The goal for the mathematical models was to predict the physical property to predicted simulation value. The simulation model approximating the FEP process used to develop the correlations was relatively complex, and not possible to duplicate within the scope of the bench scale evaporation experiments. Therefore, simulants were made of 13 design points (a subset of the points used in the model fits) using the compositions of the ultra-filtration feed streams as predicted by the simulation model. The chemistry and physical properties of the supernate (the modeled stream) as predicted by the simulation were compared with the analytical results of experimental simulant work as a method of validating the simulation software.

  16. Understanding the physics of DNA using nanoscale single-molecule manipulation.

    PubMed

    Frey, Eric W; Gooding, Ashton A; Wijeratne, Sitara; Kiang, Ching-Hwa

    2012-10-01

    Processes for decoding the genetic information in cells, including transcription, replication, recombination and repair, involve the deformation of DNA from its equilibrium structures such as bending, stretching, twisting, and unzipping of the double helix. Single-molecule manipulation techniques have made it possible to control DNA conformation and simultaneously detect the induced changes, revealing a rich variety of mechanically-induced conformational changes and thermodynamic states. These single-molecule techniques helped us to reveal the physics of DNA and the processes involved in the passing on of the genetic code. PMID:23467419

  17. Understanding the physics of DNA using nanoscale single-molecule manipulation

    PubMed Central

    Frey, Eric W.; Gooding, Ashton A.; Wijeratne, Sitara; Kiang, Ching-Hwa

    2013-01-01

    Processes for decoding the genetic information in cells, including transcription, replication, recombination and repair, involve the deformation of DNA from its equilibrium structures such as bending, stretching, twisting, and unzipping of the double helix. Single-molecule manipulation techniques have made it possible to control DNA conformation and simultaneously detect the induced changes, revealing a rich variety of mechanically-induced conformational changes and thermodynamic states. These single-molecule techniques helped us to reveal the physics of DNA and the processes involved in the passing on of the genetic code. PMID:23467419

  18. The Electronic Properties of Nanoscale Meta-lattice Made by High Pressure CVD

    NASA Astrophysics Data System (ADS)

    Huang, Zhaohui; Crespi, Vincent

    Meta-lattice can be defined as an artificial 3D superlattice with periodic structural modulation occurred at 10nm scale. One viable route to synthesize can be as follows: A template is first prepared by close-packed nanometer-sized silica spheres, then Si/Ge or a binary semiconductor is infiltrated into voids by high pressure chemical vapor deposition (CVD). Later silica spheres can be removed by chemical method, and voids in the inverse meta-latice offer the opportunity for a second infiltration. Due to the characteristic length of voids, meta-lattice provides a platform to test novel mesoscopic electronic and thermal phenomena. A meta-lattice solid can show novel physical properties that each constituent infiltrate material does not have. Since a significan portion of atoms are located on the surface, the interface structure details are expected to play a critical role. Here we investigate Si/Ge inverse meta-lattices with or without silica template present. Tight-binding, DFT and GW/BSE techniques are employed to look into the electronic and optical properties.

  19. Physical Properties of Hanford Transuranic Waste

    SciTech Connect

    Berg, John C.

    2010-03-25

    The research described herein was undertaken to provide needed physical property descriptions of the Hanford transuranic tank sludges under conditions that might exist during retrieval, treatment, packaging and transportation for disposal. The work addressed the development of a fundamental understanding of the types of systems represented by these sludge suspensions through correlation of the macroscopic rheological properties with particle interactions occurring at the colloidal scale in the various liquid media. The results of the work have advanced existing understanding of the sedimentation and aggregation properties of complex colloidal suspensions. Bench scale models were investigated with respect to their structural, colloidal and rheological properties that should be useful for the development and optimization of techniques to process the wastes at various DOE sites.

  20. Physical assessment of toxicology at nanoscale: nano dose-metrics and toxicity factor

    NASA Astrophysics Data System (ADS)

    Pompa, P. P.; Vecchio, G.; Galeone, A.; Brunetti, V.; Maiorano, G.; Sabella, S.; Cingolani, R.

    2011-07-01

    In this work, we propose a systematic and reproducible evaluation of nanoparticles (NPs) toxicology in living systems, based on a physical assessment and quantification of the toxic effects of NPs by the experimental determination of the key parameter affecting the toxicity outcome (i.e., the number of NPs) and of the NPs ``toxicity factor''. Such a strategy was applied to a well determined scenario, i.e., the ingestion of citrate-capped gold NPs (AuNPs) of different sizes by the model system Drosophila melanogaster. Using these AuNPs as a reference toxicity standard, we were able to define different regions in the multiparametric space of toxicity, enabling the classification of the toxic levels of other nanomaterials, such as quantum dots and pegylated AuNPs. This approach may pave the way to a systematic classification of nanomaterials, leading to important developments in risk assessment and regulatory approval, as well as in a wide range of nanomedicine applications.

  1. Aggrecan nanoscale solid-fluid interactions are a primary determinant of cartilage dynamic mechanical properties.

    PubMed

    Nia, Hadi Tavakoli; Han, Lin; Bozchalooi, Iman Soltani; Roughley, Peter; Youcef-Toumi, Kamal; Grodzinsky, Alan J; Ortiz, Christine

    2015-03-24

    Poroelastic interactions between interstitial fluid and the extracellular matrix of connective tissues are critical to biological and pathophysiological functions involving solute transport, energy dissipation, self-stiffening and lubrication. However, the molecular origins of poroelasticity at the nanoscale are largely unknown. Here, the broad-spectrum dynamic nanomechanical behavior of cartilage aggrecan monolayer is revealed for the first time, including the equilibrium and instantaneous moduli and the peak in the phase angle of the complex modulus. By performing a length scale study and comparing the experimental results to theoretical predictions, we confirm that the mechanism underlying the observed dynamic nanomechanics is due to solid-fluid interactions (poroelasticity) at the molecular scale. Utilizing finite element modeling, the molecular-scale hydraulic permeability of the aggrecan assembly was quantified (kaggrecan = (4.8 ± 2.8) × 10(-15) m(4)/N·s) and found to be similar to the nanoscale hydraulic permeability of intact normal cartilage tissue but much lower than that of early diseased tissue. The mechanisms underlying aggrecan poroelasticity were further investigated by altering electrostatic interactions between the molecule's constituent glycosaminoglycan chains: electrostatic interactions dominated steric interactions in governing molecular behavior. While the hydraulic permeability of aggrecan layers does not change across species and age, aggrecan from adult human cartilage is stiffer than the aggrecan from newborn human tissue. PMID:25758717

  2. Mapping viscoelastic properties of healthy and pathological red blood cells at the nanoscale level.

    PubMed

    Ciasca, G; Papi, M; Di Claudio, S; Chiarpotto, M; Palmieri, V; Maulucci, G; Nocca, G; Rossi, C; De Spirito, M

    2015-10-28

    In order to pass through the microcirculation, red blood cells (RBCs) need to undergo extensive deformations and to recover the original shape. This extreme deformability is altered by various pathological conditions. On the other hand, an altered RBC deformability can have major effects on blood flow and can lead to pathological implications. The study of the viscoelastic response of red blood cells to mechanical stimuli is crucial to fully understand deformability changes under pathological conditions. However, the typical erythrocyte biconcave shape hints to a complex and intrinsically heterogeneous mechanical response that must be investigated by using probes at the nanoscale level. In this work, the local viscoelastic behaviour of healthy and pathological red blood cells was probed by Atomic Force Microscopy (AFM). Our results clearly show that the RBC stiffness is not spatially homogeneous, suggesting a strong correlation with the erythrocyte biconcave shape. Moreover, our nanoscale mapping highlights the key role played by viscous forces, demonstrating that RBCs do not behave as pure elastic bodies. The fundamental role played by viscous forces is further strengthened by the comparison between healthy and pathological (diabetes mellitus) RBCs. It is well known that pathological RBCs are usually stiffer than the healthy ones. Our measures unveil a more complex scenario according to which the difference between normal and pathological red blood cells does not merely lie in their stiffness but also in a different dynamical response to external stimuli that is governed by viscous forces. PMID:26415744

  3. Physical properties of the planet Mercury

    NASA Technical Reports Server (NTRS)

    Clark, Pamela E.

    1988-01-01

    The global physical properties of Mercury are summarized with attention given to its figure and orbital parameters. The combination of properties suggests that Mercury has an extensive iron-rich core, possibly with a still-functioning dynamo, which is 42 percent of the interior by volume. Mercury's three major axes are comparable in size, indicating that the planet is a triaxial ellipsoid rather than an oblate spheroid. In terms of the domination of its surface by an intermediate plains terrane, it is more Venus- or Mars-like; however, due to the presence of a large metallic magnetic core, its interior may be more earth-like.

  4. F-Canyon Sludge Physical Properties

    SciTech Connect

    Poirier, M. R.; Hansen, P. R.; Fink, S. D.

    2005-08-22

    The Site Deactivation and Decommissioning (SDD) Organization is evaluating options to disposition the 800 underground tanks (including removal of the sludge heels from these tanks). To support this effort, D&D requested assistance from Savannah River National Laboratory (SRNL) personnel to determine the pertinent physical properties to effectively mobilize the sludge from these tanks (Tanks 804, 808, and 809). SDD provided SRNL with samples of the sludge from Tanks 804, 808, and 809. The authors measured the following physical properties for each tank: particle settling rate, shear strength (i.e., settled solids yield stress), slurry rheology (i.e., yield stress and consistency), total solids concentration in the sludge, soluble solids concentration of the sludge, sludge density, and particle size distribution.

  5. Physical properties of Dowell Chemical Seal Ring

    SciTech Connect

    Benny, H.L.

    1985-07-01

    This document outlines the tests, procedures, and results of an evaluation program for Dowell's Chemical Seal Ring.'' The testing reported here deals with the physical properties of density, compression, tensile strength, elongation, and a push-out/bond strength test. Dowell's Chemical Seal Ring'' is proposed as a gasket-like seal between grout layers in the annulus around the Exploratory Shaft steel liner. 4 refs., 1 fig., 4 tabs.

  6. Chemical and Physical Properties of Tantalum Powder

    NASA Astrophysics Data System (ADS)

    Purushotham, Y.; Balaji, T.; Kumar, Arbind; Govindaiah, R.; Sharma, M. K.; Sethi, V. C.; Prakash, T. L.

    The present work is intended to produce capacitor grade Tantalum powder by sodium reduction of potassium tantalum fluoride prepared from an indigenous ore source. The powder has been characterized for its chemical and physical properties, and compared with the commercially available powders. It is found that indigenous powder has higher impurity levels which could, however, be reduced to acceptance limits. The average particle size is within the prescribed limits.

  7. Physical and biological properties of Bazna waters

    PubMed Central

    TRÂMBIŢAŞ, DAN

    2013-01-01

    The healing properties of Bazna waters and their therapeutic indications have been well known since the 18th century. The objective of the present study was to characterize these waters from physical and biological points of view, and to further analyze the nitrogen compounds, especially NH4+. The following physical parameters of the water were analyzed: density (g/cm3), electric resistivity (Ω·m), electric conductivity (cm−1o−1), salinity, The pH analysis of the biological component was performed on samples from 4 basins. Nitrogen compounds were dosed in the form of ammonium ion (NH4+). The physical and chemical proprieties are similar across the basins. Flora and fauna biological components were identified. Ammonium ions were identified in large quantities, but this did not lead to hygienicaly unclean waters. PMID:26527972

  8. Spin manipulation in nanoscale superconductors

    NASA Astrophysics Data System (ADS)

    Beckmann, D.

    2016-04-01

    The interplay of superconductivity and magnetism in nanoscale structures has attracted considerable attention in recent years due to the exciting new physics created by the competition of these antagonistic ordering phenomena, and the prospect of exploiting this competition for superconducting spintronics devices. While much of the attention is focused on spin-polarized supercurrents created by the triplet proximity effect, the recent discovery of long range quasiparticle spin transport in high-field superconductors has rekindled interest in spin-dependent nonequilibrium properties of superconductors. In this review, the experimental situation on nonequilibrium spin injection into superconductors is discussed, and open questions and possible future directions of the field are outlined.

  9. Spin manipulation in nanoscale superconductors.

    PubMed

    Beckmann, D

    2016-04-27

    The interplay of superconductivity and magnetism in nanoscale structures has attracted considerable attention in recent years due to the exciting new physics created by the competition of these antagonistic ordering phenomena, and the prospect of exploiting this competition for superconducting spintronics devices. While much of the attention is focused on spin-polarized supercurrents created by the triplet proximity effect, the recent discovery of long range quasiparticle spin transport in high-field superconductors has rekindled interest in spin-dependent nonequilibrium properties of superconductors. In this review, the experimental situation on nonequilibrium spin injection into superconductors is discussed, and open questions and possible future directions of the field are outlined. PMID:27001949

  10. Nanoscale nonlinear radio frequency properties of bulk Nb: Origins of extrinsic nonlinear effects

    NASA Astrophysics Data System (ADS)

    Tai, Tamin; Ghamsari, B. G.; Bieler, T.; Anlage, Steven M.

    2015-10-01

    The performance of niobium-based superconducting radio frequency (SRF) particle-accelerator cavities can be sensitive to localized defects that give rise to quenches at high accelerating gradients. In order to identify these material defects on bulk Nb surfaces at their operating frequency and temperature, a wide-bandwidth microwave microscope with localized and strong RF magnetic fields is developed by integrating a magnetic write head into the near-field microwave microscope to enable mapping of the local electrodynamic response in the multi-GHz frequency regime at cryogenic temperatures. This magnetic writer demonstrates a localized and strong RF magnetic field on bulk Nb surface with Bsurface>102 mT and submicron resolution. By measuring the nonlinear response of the superconductor, nonlinearity coming from the nanoscale weak-link Josephson junctions due to the contaminated surface in the cavity-fabrication process is demonstrated.

  11. Mapping viscoelastic properties of healthy and pathological red blood cells at the nanoscale level

    NASA Astrophysics Data System (ADS)

    Ciasca, G.; Papi, M.; di Claudio, S.; Chiarpotto, M.; Palmieri, V.; Maulucci, G.; Nocca, G.; Rossi, C.; de Spirito, M.

    2015-10-01

    In order to pass through the microcirculation, red blood cells (RBCs) need to undergo extensive deformations and to recover the original shape. This extreme deformability is altered by various pathological conditions. On the other hand, an altered RBC deformability can have major effects on blood flow and can lead to pathological implications. The study of the viscoelastic response of red blood cells to mechanical stimuli is crucial to fully understand deformability changes under pathological conditions. However, the typical erythrocyte biconcave shape hints to a complex and intrinsically heterogeneous mechanical response that must be investigated by using probes at the nanoscale level. In this work, the local viscoelastic behaviour of healthy and pathological red blood cells was probed by Atomic Force Microscopy (AFM). Our results clearly show that the RBC stiffness is not spatially homogeneous, suggesting a strong correlation with the erythrocyte biconcave shape. Moreover, our nanoscale mapping highlights the key role played by viscous forces, demonstrating that RBCs do not behave as pure elastic bodies. The fundamental role played by viscous forces is further strengthened by the comparison between healthy and pathological (diabetes mellitus) RBCs. It is well known that pathological RBCs are usually stiffer than the healthy ones. Our measures unveil a more complex scenario according to which the difference between normal and pathological red blood cells does not merely lie in their stiffness but also in a different dynamical response to external stimuli that is governed by viscous forces.In order to pass through the microcirculation, red blood cells (RBCs) need to undergo extensive deformations and to recover the original shape. This extreme deformability is altered by various pathological conditions. On the other hand, an altered RBC deformability can have major effects on blood flow and can lead to pathological implications. The study of the viscoelastic

  12. Probing mechanical properties of thin film and ceramic materials in micro- and nano-scale using indentation techniques

    NASA Astrophysics Data System (ADS)

    Charitidis, Costas A.

    2010-10-01

    In this study, we report on the mechanical properties, failure and fracture modes in two cases of engineering materials; that is transparent silicon oxide thin films onto poly(ethylene terephthalate) (PET) membranes and glass-ceramic materials. The first system was studied by the quazi-static indentation technique at the nano-scale and the second by the static indentation technique at the micro-scale. Nanocomposite laminates of silicon oxide thin films onto PET were found to sustain higher scratch induced stresses and were effective as protective coating material for PET membranes. Glass-ceramic materials with separated crystallites of different morphologies sustained a mixed crack propagation pattern in brittle fracture mode.

  13. The influence of the ion beam on the structure and optical properties of titanium nitride nano-scale thin films

    NASA Astrophysics Data System (ADS)

    Odeh, Ibrahim; Elian, Rajaa

    2015-12-01

    Titanium nitride nano-scale thin films have been prepared by ion beam assisted reactive DC magnetron sputtering. The films are characterized by XRD, SEM and TEM. The films are found to be amorphous. The effect of the ion beam during deposition was evident from smoothness of film surface (SEM and TEM images) and modifications in optical properties. Investigation of the optical constants shows stable refractive index dominating most of the visible range. The films are not highly absorptive in the visible range. An energy gap of 2.9 ± 0.1 eV is estimated for the IBAD amorphous titanium nitride nano-thin films. The stability of the films at normal room environment in addition to the golden color makes the nano-thin films suitable for hard and decorative coatings.

  14. Precipitation of nanoscale mercuric sulfides in the presence of natural organic matter: Structural properties, aggregation, and biotransformation

    NASA Astrophysics Data System (ADS)

    Pham, Anh Le-Tuan; Morris, Amanda; Zhang, Tong; Ticknor, Jonathan; Levard, Clément; Hsu-Kim, Heileen

    2014-05-01

    Mercuric sulfide species are likely the predominant forms of mercury (Hg) in anoxic environments where the bioavailability of Hg is a key factor for the production of methylmercury (MeHg) by microorganisms. Dissolved organic matter (DOM) is known to affect the formation, aggregation, and dissolution of HgS particles; however the connection of these processes to Hg bioavailability is not well understood. The objectives of this study were to gain insights into the molecular structure and aggregation properties of nanoscale HgS particles that were formed and aged in the presence of DOM and to link this information to bioavailability for methylating bacteria. Characterization of nanoscale HgS was performed with a series of techniques including transmission electron microscopy, photon scattering, X-ray diffraction, and X-ray absorption spectroscopy. The characterization results indicated that the HgS precipitates formed were metacinnabar-like spherical nanoparticles that were 3-5 nm in diameter. Over the course of the aging process, HgS nanoparticles (nano-HgS) agglomerated to form mass-fractal aggregates, although the size of each primary particle within the aggregates remained unchanged. Furthermore, the crystallinity of nano-HgS increased as the particles aged. The methylation potential of nano-HgS by sulfate-reducing bacteria decreased during the aging process. No clear correlation was observed between the net productions of MeHg and the concentrations of dissolved Hg(II) in the culture media, suggesting that the decrease in the methylation potential of aged nano-HgS was not simply because of the slower supply of dissolved Hg(II) by nano-HgS. While the link between the aging of nano-HgS and decrease of methylation potential is not fully understood, the results of our study indicate that freshly formed HgS particles in DOM-rich water will include a variety of nanoscale structures that have a wide range of methylation potentials. This knowledge provides a basis for

  15. Physical Properties of Synthetic Resin Materials

    NASA Technical Reports Server (NTRS)

    Fishbein, Meyer

    1939-01-01

    A study was made to determine the physical properties of synthetic resins having paper, canvas, and linen reinforcements, and of laminated wood impregnated with a resin varnish. The results show that commercial resins have moduli of elasticity that are too low for structural considerations. Nevertheless, there do exist plastics that have favorable mechanical properties and, with further development, it should be possible to produce resin products that compare favorably with the light-metal alloys. The results obtained from tests on Compound 1840, resin-impregnated wood, show that this material can stand on its own merit by virtue of a compressive strength four times that of the natural wood. This increase in compressive strength was accomplished with an increase of density to a value slightly below three times the normal value and corrected one of the most serious defects of the natural product.

  16. Self-assembled nanoscale coordination polymers with trigger release properties for effective anticancer therapy

    NASA Astrophysics Data System (ADS)

    Liu, Demin; Poon, Christopher; Lu, Kuangda; He, Chunbai; Lin, Wenbin

    2014-06-01

    Nanoscale coordination polymers (NCPs) are self-assembled from metal ions and organic bridging ligands, and can overcome many drawbacks of existing drug delivery systems by virtue of tunable compositions, sizes and shapes, high drug loadings, ease of surface modification and intrinsic biodegradability. Here we report the self-assembly of zinc bisphosphonate NCPs that carry 48±3 wt% cisplatin prodrug and 45±5 wt% oxaliplatin prodrug. In vivo pharmacokinetic studies in mice show minimal uptake of pegylated NCPs by the mononuclear phagocyte system and excellent blood circulation half-lives of 16.4±2.9 and 12.0±3.9 h for the NCPs carrying cisplatin and oxaliplatin, respectively. In all tumour xenograft models evaluated, including CT26 colon cancer, H460 lung cancer and AsPC-1 pancreatic cancer, pegylated NCPs show superior potency and efficacy compared with free drugs. As the first example of using NCPs as nanotherapeutics with enhanced antitumour activities, this study establishes NCPs as a promising drug delivery platform for cancer therapy.

  17. Self-assembled nanoscale coordination polymers with trigger release properties for effective anticancer therapy

    PubMed Central

    Liu, Demin; Poon, Christopher; Lu, Kuangda; He, Chunbai; Lin, Wenbin

    2014-01-01

    Nanoscale coordination polymers (NCPs) are self-assembled from metal ions and organic bridging ligands, and can overcome many drawbacks of existing drug delivery systems by virtue of tunable compositions, sizes, and shapes; high drug loadings; ease of surface modification; and intrinsic biodegradability. Here we report the self-assembly of zinc bisphosphonate NCPs that carry 48±3 wt% cisplatin prodrug and 45±5 wt% oxaliplatin prodrug. In vivo pharmacokinetic studies in mice show minimal uptake of pegylated NCPs by the mononuclear phagocyte system and excellent blood circulation half-lives of 16.4±2.9 and 12.0±3.9 h for the NCPs carrying cisplatin and oxaliplatin, respectively. In all tumor xenograft models evaluated, including CT26 colon cancer, H460 lung cancer, and AsPC-1 pancreatic cancer, pegylated NCPs show superior potency and efficacy compared to free drugs. As the first example of using NCPs as nanotherapeutics with enhanced antitumor activities, this study establishes NCPs as a promising drug delivery platform for cancer therapy. PMID:24964370

  18. Physical Properties of the Glycoprotein Mucin

    NASA Astrophysics Data System (ADS)

    Matthews, Garrett; Davis, William; Superfine, Richard; Boucher, Richard

    2003-03-01

    Epithelial cell surfaces are covered by a protective gel known as mucus. The physiological function of this gel depends on its rheological properties, and these properties are largely derived from the secreted glycoprotein mucin. The genetic disease Cystic Fibrosis (CF) is characterized by the adhesion of thick, viscous mucus on these tissues. In the lungs, this results in the interruption of mucus transport thus compromising the first line of defense against pathogens in these tissues. In order to restore the flow of tracheobronchial mucus out of the body, knowledge of the molecular and physical properties of mucin and mucin solutions would be greatly beneficial. The present model for these molecules is that of a long linear strand consisting of highly glycosylated regions linked by cystein-rich globular regions. It is thought that the globular regions may interact either through intermolecular disulfide bonds or through hydrophobic interactions. It has also been speculated that the glycosylated regions may have lectin-like interactions. In the present work, single mucin molecules were imaged at high resolution using atomic force microscopy (AFM). Phase mode imaging was used to map the interactions between functionalized AFM tips and the molecular topography. Additionally, using force-distance curves with the AFM, the adhesion between mucin bound tips and cell surface glycocalyx and glycocalyx-like model surfaces, was measured. And, finally, the viscoelastic properties of mucin solutions were measured using the recently developed technique, single particle tracking microrheology. A model is being developed that will incorporate the properties of mucins beginning at the single molecule and ending with the bulk viscoelastic properties.

  19. Comparison of micro- and nanoscale Fe⁺³-containing (Hematite) particles for their toxicological properties in human lung cells in vitro.

    PubMed

    Bhattacharya, Kunal; Hoffmann, Eik; Schins, Roel F P; Boertz, Jens; Prantl, Eva-Maria; Alink, Gerrit M; Byrne, Hugh James; Kuhlbusch, Thomas A J; Rahman, Qamar; Wiggers, Hartmut; Schulz, Christof; Dopp, Elke

    2012-03-01

    The specific properties of nanoscale particles, large surface-to-mass ratios and highly reactive surfaces, have increased their commercial application in many fields. However, the same properties are also important for the interaction and bioaccumulation of the nonbiodegradable nanoscale particles in a biological system and are a cause for concern. Hematite (α-Fe₂O₃), being a mineral form of Fe(III) oxide, is one of the most used iron oxides besides magnetite. The aim of our study was the characterization and comparison of biophysical reactivity and toxicological effects of α-Fe₂O₃ nano- (d < 100 nm) and microscale (d < 5 μm) particles in human lung cells. Our study demonstrates that the surface reactivity of nanoscale α-Fe₂O₃ differs from that of microscale particles with respect to the state of agglomeration, radical formation potential, and cellular toxicity. The presence of proteins in culture medium and agglomeration were found to affect the catalytic properties of the hematite nano- and microscale particles. Both the nano- and microscale α-Fe₂O₃ particles were actively taken up by human lung cells in vitro, although they were not found in the nuclei and mitochondria. Significant genotoxic effects were only found at very high particle concentrations (> 50 μg/ml). The nanoscale particles were slightly more potent in causing cyto- and genotoxicity as compared with their microscale counterparts. Both types of particles induced intracellular generation of reactive oxygen species. This study underlines that α-Fe₂O₃ nanoscale particles trigger different toxicological reaction pathways than microscale particles. However, the immediate environment of the particles (biomolecules, physiological properties of medium) modulates their toxicity on the basis of agglomeration rather than their actual size. PMID:22262566

  20. HYDRAULIC AND PHYSICAL PROPERTIES OF MCU SALTSTONE

    SciTech Connect

    Dixon, K; Mark Phifer, M

    2008-03-19

    The Saltstone Disposal Facility (SDF), located in the Z-Area of the Savannah River Site (SRS), is used for the disposal of low-level radioactive salt solution. The SDF currently contains two vaults: Vault 1 (6 cells) and Vault 4 (12 cells). Additional disposal cells are currently in the design phase. The individual cells of the saltstone facility are filled with saltstone., Saltstone is produced by mixing the low-level radioactive salt solution, with blast furnace slag, fly ash, and cement or lime to form a dense, micro-porous, monolithic, low-level radioactive waste form. The saltstone is pumped into the disposal cells where it subsequently solidifies. Significant effort has been undertaken to accurately model the movement of water and contaminants through the facility. Key to this effort is an accurate understanding of the hydraulic and physical properties of the solidified saltstone. To date, limited testing has been conducted to characterize the saltstone. The primary focus of this task was to estimate the hydraulic and physical properties of MCU (Modular Caustic Side Solvent Extraction Unit) saltstone relative to two permeating fluids. These fluids included simulated groundwater equilibrated with vault concrete and simulated saltstone pore fluid. Samples of the MCU saltstone were prepared by the Savannah River National Laboratory (SRNL) and allowed to cure for twenty eight days prior to testing. These samples included two three-inch diameter by six inch long mold samples and three one-inch diameter by twelve inch long mold samples.

  1. Mueller based scatterometry measurement of nanoscale structures with anisotropic in-plane optical properties

    NASA Astrophysics Data System (ADS)

    Muthinti, Gangadhara R.; Medikonda, Manasa; Fronheiser, Jody; Kamineni, Vimal K.; Peterson, Brennan; Race, Joseph; Diebold, Alain C.

    2013-04-01

    The uses of strained channel became prevalent at the 65 nm node and have continued to be a large part of logic device performance improvements in every technology generation. These material and integration innovations will continue to be important in sub-22nm devices, and are already being applied in finFET devices where total available in-channel strains are potentially higher. The measurement of structures containing these materials is complicated by the intrinsic correlation of the measured optical thickness and variation of optical properties with strain, as well as the dramatic reduction in total volume of the device. Optical scatterometry has enabled characterization of the feature shape and dimensions of complex 3D structures, including non-planar transistors and memory structures. Ellipsometric methods have been successfully applied to the measurement of thin films of SiGe and related strained structures. A direction for research is validating that the thin film stress results can be extended into the much more physically complex 3D shape. There are clear challenges in this: the stress in a SiGe fin is constrained to match the underlying Si along one axis, but the sides and top are free, leading to very large strain gradients both along the fin width and height. Practical utilization of optical techniques as a development tool is often limited by the complexity of the scatterometry model and setup, and this added material complexity presents a new challenge. In this study, generalized spectroscopic ellipsometric measurements of strained grating was undertaken, in parallel with reference cross sectional and top down SEM data. The measurements were modeled for both anisotropy calculations, as well as full scatterometry calculations, fitting the strain and structure. The degree to which strain and CD can be quickly quantified in an optical model is discussed. Sum decomposition method has been implemented to extract the effective anisotropic coefficients and a

  2. Physical Properties of Fractured Porous Media

    NASA Astrophysics Data System (ADS)

    Mohammed, T. E.; Schmitt, D. R.

    2015-12-01

    The effect of fractures on the physical properties of porous media is of considerable interest to oil and gas exploration as well as enhanced geothermal systems and carbon capture and storage. This work represents an attempt to study the effect fractures have on multiple physical properties of rocks. An experimental technique to make simultaneous electric and ultrasonic measurements on cylindrical core plugs is developed. Aluminum end caps are mounted with ultrasonic transducers to transmit pules along the axis of the cylinder while non-polarizing electrodes are mounted on the sides of the core to make complex conductivity measurements perpendicular to the cylinder axis. Electrical measurements are made by applying a sinusoidal voltage across the measurement circuit that consist of a resister and the sample in series. The magnitude and phase of the signal across the sample is recorded relative to the input signal across a range of frequencies. Synthetic rock analogs are constructed using sintered glass beads with fractures imbedded in them. The fracture location, size and orientation are controlled and each fractured specimen has an unfractured counterpart. Porosity, Permeability, electrical conductivity and ultrasonic velocity measurements are conducted on each sample with the complex electrical conductivities recorded at frequencies from 10hz to 1 Mhz. These measurements allow us to examine the changes induced by these mesoscale fractures on the embedding porous medium. Of particular interest is the effect of fracture orientation on electrical conductivity of the rock. Seismic anisotropy caused by fractures is a well understood phenomenon with many rock physics models dedicated to its understanding. The effect of fractures on electrical conductivity is less well understood with electrical anisotropy scarcely investigated in the literature. None the less, using electrical conductivity to characterize fractures can add an extra constraint to characterization based

  3. Nanoscale morphology of multilayer PbTe/CdTe heterostructures and its effect on photoluminescence properties

    NASA Astrophysics Data System (ADS)

    Karczewski, G.; Szot, M.; Kret, S.; Kowalczyk, L.; Chusnutdinow, S.; Wojtowicz, T.; Schreyeck, S.; Brunner, K.; Schumacher, C.; Molenkamp, L. W.

    2015-03-01

    We study nanoscale morphology of PbTe/CdTe multilayer heterostuctures grown by molecular beam epitaxy on hybrid GaAs/CdTe (100) substrates. Nominally, the structures consist of 25 repetitions of subsequently deposited CdTe and PbTe layers with comparable thicknesses of 21 and 8 nm, respectively. However, the morphology of the resulting structures crucially depends on the growth temperature. The two-dimensional layered, superlattice-like character of the structures remains preserved only when grown at low substrate temperatures, such as 230 °C. The samples grown at the slightly elevated temperature of 270 °C undergo a morphological transformation to structures consisting of CdTe and PbTe pillars and columns oriented perpendicular to the substrate. Although the pillar-like objects are of various shapes and dimensions these structures exhibit exceptionally strong photoluminescence in the near infrared spectral region. At the higher growth temperature of 310 °C, PbTe and CdTe separate completely forming thick layers oriented longitudinally to the substrate plane. The observed topological transformations are driven by thermally activated atomic diffusion in the solid state phase. The solid state phase remains fully coherent during the processes. The observed topological transitions leading to the material separation in PbTe/CdTe system could be regarded as an analog of spinodal decomposition of an immiscible solid state solution and thus they can be qualitatively described by the Cahn-Hillard model as proposed by Groiss et al (2014 APL Mater. 2 012105).

  4. Descriptors, physical properties, and drug-likeness.

    PubMed

    Brüstle, Matthias; Beck, Bernd; Schindler, Torsten; King, William; Mitchell, Timothy; Clark, Timothy

    2002-08-01

    We have investigated techniques for distinguishing between drugs and nondrugs using a set of molecular descriptors derived from semiempirical molecular orbital (AM1) calculations. The "drug" data set of 2105 compounds was derived from the World Drug Index (WDI) using a procedure designed to select real drugs. The "nondrug" data set was the Maybridge database. We have first investigated the dimensionality of physical properties space based on a set of 26 descriptors that we have used successfully to build absorption, distribution, metabolism, and excretion-related quantitative structure-property relationship models. We discuss the general nature of the descriptors for physical property space and the ability of these descriptors to distinguish between drugs and nondrugs. The third most significant principal component of this set of descriptors serves as a useful numerical index of drug-likeness, but no others are able to distinguish between drugs and nondrugs. We have therefore extended our set of descriptors to a total of 66 and have used recursive partitioning to identify the descriptors that can distinguish between drugs and nondrugs. This procedure pointed to two of the descriptors that play an important role in the principal component found above and one more from the set of 40 extra descriptors. These three descriptors were then used to train a Kohonen artificial neural net for the entire Maybridge data set. Projecting the drug database onto the map obtained resulted in a clear distinction not only between drugs and nondrugs but also, for instance, between hormones and other drugs. Projection of 42 131 compounds from the WDI onto the Kohonen map also revealed pronounced clustering in the regions of the map assigned as druglike. PMID:12139446

  5. Structural, electronic, optical and vibrational properties of nanoscale carbons and nanowires: a colloquial review

    NASA Astrophysics Data System (ADS)

    Cole, Milton W.; Crespi, Vincent H.; Dresselhaus, Mildred S.; Dresselhaus, Gene; Fischer, John E.; Gutierrez, Humberto R.; Kojima, K.; Mahan, Gerald D.; Rao, Apparao M.; Sofo, Jorge O.; Tachibana, M.; Wako, K.; Xiong, Qihua

    2010-08-01

    This review addresses the field of nanoscience as viewed through the lens of the scientific career of Peter Eklund, thus with a special focus on nanocarbons and nanowires. Peter brought to his research an intense focus, imagination, tenacity, breadth and ingenuity rarely seen in modern science. His goal was to capture the essential physics of natural phenomena. This attitude also guides our writing: we focus on basic principles, without sacrificing accuracy, while hoping to convey an enthusiasm for the science commensurate with Peter's. The term 'colloquial review' is intended to capture this style of presentation. The diverse phenomena of condensed matter physics involve electrons, phonons and the structures within which excitations reside. The 'nano' regime presents particularly interesting and challenging science. Finite size effects play a key role, exemplified by the discrete electronic and phonon spectra of C60 and other fullerenes. The beauty of such molecules (as well as nanotubes and graphene) is reflected by the theoretical principles that govern their behavior. As to the challenge, 'nano' requires special care in materials preparation and treatment, since the surface-to-volume ratio is so high; they also often present difficulties of acquiring an experimental signal, since the samples can be quite small. All of the atoms participate in the various phenomena, without any genuinely 'bulk' properties. Peter was a master of overcoming such challenges. The primary activity of Eklund's research was to measure and understand the vibrations of atoms in carbon materials. Raman spectroscopy was very dear to Peter. He published several papers on the theory of phonons (Eklund et al 1995a Carbon 33 959-72, Eklund et al 1995b Thin Solid Films 257 211-32, Eklund et al 1992 J. Phys. Chem. Solids 53 1391-413, Dresselhaus and Eklund 2000 Adv. Phys. 49 705-814) and many more papers on measuring phonons (Pimenta et al 1998b Phys. Rev. B 58 16016-9, Rao et al 1997a Nature

  6. Structural, electronic, optical and vibrational properties of nanoscale carbons and nanowires: a colloquial review.

    PubMed

    Cole, Milton W; Crespi, Vincent H; Dresselhaus, Mildred S; Dresselhaus, Gene; Fischer, John E; Gutierrez, Humberto R; Kojima, K; Mahan, Gerald D; Rao, Apparao M; Sofo, Jorge O; Tachibana, M; Wako, K; Xiong, Qihua

    2010-08-25

    This review addresses the field of nanoscience as viewed through the lens of the scientific career of Peter Eklund, thus with a special focus on nanocarbons and nanowires. Peter brought to his research an intense focus, imagination, tenacity, breadth and ingenuity rarely seen in modern science. His goal was to capture the essential physics of natural phenomena. This attitude also guides our writing: we focus on basic principles, without sacrificing accuracy, while hoping to convey an enthusiasm for the science commensurate with Peter's. The term 'colloquial review' is intended to capture this style of presentation. The diverse phenomena of condensed matter physics involve electrons, phonons and the structures within which excitations reside. The 'nano' regime presents particularly interesting and challenging science. Finite size effects play a key role, exemplified by the discrete electronic and phonon spectra of C(60) and other fullerenes. The beauty of such molecules (as well as nanotubes and graphene) is reflected by the theoretical principles that govern their behavior. As to the challenge, 'nano' requires special care in materials preparation and treatment, since the surface-to-volume ratio is so high; they also often present difficulties of acquiring an experimental signal, since the samples can be quite small. All of the atoms participate in the various phenomena, without any genuinely 'bulk' properties. Peter was a master of overcoming such challenges. The primary activity of Eklund's research was to measure and understand the vibrations of atoms in carbon materials. Raman spectroscopy was very dear to Peter. He published several papers on the theory of phonons (Eklund et al 1995a Carbon 33 959-72, Eklund et al 1995b Thin Solid Films 257 211-32, Eklund et al 1992 J. Phys. Chem. Solids 53 1391-413, Dresselhaus and Eklund 2000 Adv. Phys. 49 705-814) and many more papers on measuring phonons (Pimenta et al 1998b Phys. Rev. B 58 16016-9, Rao et al 1997a Nature

  7. Determining Physical Properties of the Cell Cortex.

    PubMed

    Saha, Arnab; Nishikawa, Masatoshi; Behrndt, Martin; Heisenberg, Carl-Philipp; Jülicher, Frank; Grill, Stephan W

    2016-03-29

    Actin and myosin assemble into a thin layer of a highly dynamic network underneath the membrane of eukaryotic cells. This network generates the forces that drive cell- and tissue-scale morphogenetic processes. The effective material properties of this active network determine large-scale deformations and other morphogenetic events. For example, the characteristic time of stress relaxation (the Maxwell time τM) in the actomyosin sets the timescale of large-scale deformation of the cortex. Similarly, the characteristic length of stress propagation (the hydrodynamic length λ) sets the length scale of slow deformations, and a large hydrodynamic length is a prerequisite for long-ranged cortical flows. Here we introduce a method to determine physical parameters of the actomyosin cortical layer in vivo directly from laser ablation experiments. For this we investigate the cortical response to laser ablation in the one-cell-stage Caenorhabditis elegans embryo and in the gastrulating zebrafish embryo. These responses can be interpreted using a coarse-grained physical description of the cortex in terms of a two-dimensional thin film of an active viscoelastic gel. To determine the Maxwell time τM, the hydrodynamic length λ, the ratio of active stress ζΔμ, and per-area friction γ, we evaluated the response to laser ablation in two different ways: by quantifying flow and density fields as a function of space and time, and by determining the time evolution of the shape of the ablated region. Importantly, both methods provide best-fit physical parameters that are in close agreement with each other and that are similar to previous estimates in the two systems. Our method provides an accurate and robust means for measuring physical parameters of the actomyosin cortical layer. It can be useful for investigations of actomyosin mechanics at the cellular-scale, but also for providing insights into the active mechanics processes that govern tissue-scale morphogenesis. PMID

  8. The influence of nanoscale roughness and substrate chemistry on the frictional properties of single and few layer graphene

    NASA Astrophysics Data System (ADS)

    Spear, Jessica C.; Custer, James P.; Batteas, James D.

    2015-05-01

    Nanoscale carbon lubricants such as graphene, have garnered increased interest as protective surface coatings for devices, but its tribological properties have been shown to depend on its interactions with the underlying substrate surface and its degree of surface conformity. This conformity is especially of interest as real interfaces exhibit roughness on the order of ~10 nm that can dramatically impact the contact area between the graphene film and the substrate. To examine the combined effects of surface interaction strength and roughness on the frictional properties of graphene, a combination of Atomic Force Microscopy (AFM) and Raman microspectroscopy has been used to explore substrate interactions and the frictional properties of single and few-layer graphene as a coating on silica nanoparticle films, which yield surfaces that mimic the nanoscaled asperities found in realistic devices. The interactions between the graphene and the substrate have been controlled by comparing their binding to hydrophilic (silanol terminated) and hydrophobic (octadecyltrichlorosilane modified) silica surfaces. AFM measurements revealed that graphene only partially conforms to the rough surfaces, with decreasing conformity, as the number of layers increase. Under higher mechanical loading the graphene conformity could be reversibly increased, allowing for a local estimation of the out-of-plane bending modulus of the film. The frictional properties were also found to depend on the number of layers, with the largest friction observed on single layers, ultimately decreasing to that of bulk graphite. This trend however, was found to disappear, depending on the tip-sample contact area and interfacial shear strain of the graphene associated with its adhesion to the substrate.Nanoscale carbon lubricants such as graphene, have garnered increased interest as protective surface coatings for devices, but its tribological properties have been shown to depend on its interactions with the

  9. Physical Properties of Thin Film Semiconducting Materials

    NASA Astrophysics Data System (ADS)

    Bouras, N.; Djebbouri, M.; Outemzabet, R.; Sali, S.; Zerrouki, H.; Zouaoui, A.; Kesri, N.

    2005-10-01

    The physics and chemistry of semiconducting materials is a continuous question of debate. We can find a large stock of well-known properties but at the same time, many things are not understood. In recent years, porous silicon (PS-Si), diselenide of copper and indium (CuInSe2 or CIS) and metal oxide semiconductors like tin oxide (SnO2) and zinc oxide (ZnO) have been subjected to extensive studies because of the rising interest their potential applications in fields such as electronic components, solar panels, catalysis, gas sensors, in biocompatible materials, in Li-based batteries, in new generation of MOSFETS. Bulk structure and surface and interface properties play important roles in all of these applications. A deeper understanding of these fundamental properties would impact largely on technological application performances. In our laboratory, thin films of undoped and antimony-doped films of tin oxide have been deposited by chemical vapor deposition. Spray pyrolysis was used for ZnO. CIS was prepared by flash evaporation or close-space vapor transport. Some of the deposition parameters have been varied, such as substrate temperature, time of deposition (or anodization), and molar concentration of bath preparation. For some samples, thermal annealing was carried out under oxygen (or air), under nitrogen gas and under vacuum. Deposition and post-deposition parameters are known to strongly influence film structure and electrical resistivity. We investigated the influence of film thickness and thermal annealing on structural optical and electrical properties of the films. Examination of SnO2 by x-ray diffraction showed that the main films are polycrystalline with rutile structure. The x-ray spectra of ZnO indicated a hexagonal wurtzite structure. Characterizations of CIS films with compositional analysis, x-ray diffraction, scanning microscopy, spectrophotometry, and photoluminescence were carried out.

  10. Physical Properties of the Uranian Satellites

    NASA Technical Reports Server (NTRS)

    Brown, R. H.

    1984-01-01

    Recent work on the satellites of Uranus revealed many of their basic physical properties. Radiometric measurements showed that the Ariel, Umbriel, Titania and Oberon have diameters which range from 1630 to 1110 km and albedos which range from 0.30 to 0.18. Spectrophotometric observations of Miranda suggest that it may have the highest albedo of the known Uranian satellites and a diameter of about 500 km. Near-infrared measurements show that Ariel, Titania and Oberon have the largest known opposition surges. All five known satellites of Uranus have surfaces which are composed of water ice contaminated with small amounts of dark material. The dark material on the surfaces of Ariel, Umbriel, Titania and Oberon is spectrally bland and has spectral similarities to carbon black, charcoal, carbonaceous chondritic material and other dark, spectrally neutral materials. Recent density determinations suggest that there may be large density differences among Ariel, Umbriel, Titania and Oberon, with density increasing with distance from Uranus.

  11. Physical Properties of Hanford Transuranic Waste Sludge

    SciTech Connect

    Poloski, A.; Berg, Dr.

    2003-06-01

    Since the start of this project in March of 2004 two main goals have been achieved. First, the laboratory facilities of the Center for Surfaces, Polymers and Colloids (SPC) at the University of Washington have been updated with the purchase and installation of two state-of-the-art analysis tools. Second, a study of the sedimentation behavior of high density colloidal solids in complex media has been performed. The results of this study were presented at the 78th ACS Colloid and Surface Science Symposium at Yale University in New Haven, CT, and have been submitted for publication to the Journal of Colloid and Interface Science. Both the new equipment and the results of the initial study will help to gain insight into the physical properties of Hanford transuranic waste sludge.

  12. Physical properties of the Uranian satellites

    SciTech Connect

    Brown, R.H.

    1984-10-01

    Recent work on the satellites of Uranus revealed many of their basic physical properties. Radiometric measurements showed that the Ariel, Umbriel, Titania and Oberon have diameters which range from 1630 to 1110 km and albedos which range from 0.30 to 0.18. Spectrophotometric observations of Miranda suggest that it may have the highest albedo of the known Uranian satellites and a diameter of about 500 km. Near-infrared measurements show that Ariel, Titania and Oberon have the largest known opposition surges. All five known satellites of Uranus have surfaces which are composed of water ice contaminated with small amounts of dark material. The dark material on the surfaces of Ariel, Umbriel, Titania and Oberon is spectrally bland and has spectral similarities to carbon black, charcoal, carbonaceous chondritic material and other dark, spectrally neutral materials. Recent density determinations suggest that there may be large density differences among Ariel, Umbriel, Titania and Oberon, with density increasing with distance from Uranus.

  13. EDITORIAL: Nanoscale metrology Nanoscale metrology

    NASA Astrophysics Data System (ADS)

    Picotto, G. B.; Koenders, L.; Wilkening, G.

    2009-08-01

    Instrumentation and measurement techniques at the nanoscale play a crucial role not only in extending our knowledge of the properties of matter and processes in nanosciences, but also in addressing new measurement needs in process control and quality assurance in industry. Micro- and nanotechnologies are now facing a growing demand for quantitative measurements to support the reliability, safety and competitiveness of products and services. Quantitative measurements presuppose reliable and stable instruments and measurement procedures as well as suitable calibration artefacts to ensure the quality of measurements and traceability to standards. This special issue of Measurement Science and Technology presents selected contributions from the Nanoscale 2008 seminar held at the Istituto Nazionale di Ricerca Metrologica (INRIM), Torino, in September 2008. This was the 4th Seminar on Nanoscale Calibration Standards and Methods and the 8th Seminar on Quantitative Microscopy (the first being held in 1995). The seminar was jointly organized by the Nanometrology Group within EUROMET (The European Collaboration in Measurement Standards), the German Nanotechnology Competence Centre 'Ultraprecise Surface Figuring' (CC-UPOB), the Physikalisch-Technische Bundesanstalt (PTB) and INRIM. A special event during the seminar was the 'knighting' of Günter Wilkening from PTB, Braunschweig, Germany, as the 1st Knight of Dimensional Nanometrology. Günter Wilkening received the NanoKnight Award for his outstanding work in the field of dimensional nanometrology over the last 20 years. The contributions in this special issue deal with the developments and improvements of instrumentation and measurement methods for scanning force microscopy (SFM), electron and optical microscopy, high-resolution interferometry, calibration of instruments and new standards, new facilities and applications including critical dimension (CD) measurements on small and medium structures and nanoparticle

  14. A novel nanoscale low-voltage SOI MOSFET with dual tunnel diode (DTD-SOI): Investigation and fundamental physics

    NASA Astrophysics Data System (ADS)

    Anvarifard, Mohammad K.; Orouji, Ali A.

    2015-06-01

    In this paper, critical electrical characteristics of a nanoscale low-voltage partially-depleted silicon-on-insulator (PD-SOI) MOSFET have been improved in terms of floating body effect, short channel effects, subthreshold swing, leakage current, self-heating effect, voltage gain, parasitic bipolar device effect, parasitic capacitance, and unilateral power gain. The heart of the proposed structure is a dual tunnel diode formed by a heavily doped P-type L-shaped trench. The accumulated holes are effectively released by the tunnel current of the dual tunnel diode. The proposed structure is found to be free of kink effect. Other substantial parameters of the proposed structure have been improved owing to L-shaped trench. Comparing the proposed structure with a conventional SOI (C-SOI), the proposed structure is considered as an undeniable contender in nanoscale integrated applications.

  15. Acoustic Imaging of Snowpack Physical Properties

    NASA Astrophysics Data System (ADS)

    Kinar, N. J.; Pomeroy, J. W.

    2011-12-01

    Measurements of snowpack depth, density, structure and temperature have often been conducted by the use of snowpits and invasive measurement devices. Previous research has shown that acoustic waves passing through snow are capable of measuring these properties. An experimental observation device (SAS2, System for the Acoustic Sounding of Snow) was used to autonomously send audible sound waves into the top of the snowpack and to receive and process the waves reflected from the interior and bottom of the snowpack. A loudspeaker and microphone array separated by an offset distance was suspended in the air above the surface of the snowpack. Sound waves produced from a loudspeaker as frequency-swept sequences and maximum length sequences were used as source signals. Up to 24 microphones measured the audible signal from the snowpack. The signal-to-noise ratio was compared between sequences in the presence of environmental noise contributed by wind and reflections from vegetation. Beamforming algorithms were used to reject spurious reflections and to compensate for movement of the sensor assembly during the time of data collection. A custom-designed circuit with digital signal processing hardware implemented an inversion algorithm to relate the reflected sound wave data to snowpack physical properties and to create a two-dimensional image of snowpack stratigraphy. The low power consumption circuit was powered by batteries and through WiFi and Bluetooth interfaces enabled the display of processed data on a mobile device. Acoustic observations were logged to an SD card after each measurement. The SAS2 system was deployed at remote field locations in the Rocky Mountains of Alberta, Canada. Acoustic snow properties data was compared with data collected from gravimetric sampling, thermocouple arrays, radiometers and snowpit observations of density, stratigraphy and crystal structure. Aspects for further research and limitations of the acoustic sensing system are also discussed.

  16. Nanoscale characterization of the biomechanical properties of collagen fibrils in the sclera

    SciTech Connect

    Papi, M.; Paoletti, P.; Geraghty, B.; Akhtar, R.

    2014-03-10

    We apply the PeakForce Quantitative Nanomechanical Property Mapping (PFQNM) atomic force microscopy mode for the investigation of regional variations in the nanomechanical properties of porcine sclera. We examine variations in the collagen fibril diameter, adhesion, elastic modulus and dissipation in the posterior, equatorial and anterior regions of the sclera. The mean fibril diameter, elastic modulus and dissipation increased from the posterior to the anterior region. Collagen fibril diameter correlated linearly with elastic modulus. Our data matches the known macroscopic mechanical behavior of the sclera. We propose that PFQNM has significant potential in ocular biomechanics and biophysics research.

  17. The ``Music" of Silica-Poly(methyl methacrylate) Core-Shell Spheres: Eigenvibrations and Mechanical Properties at the Nanoscale

    NASA Astrophysics Data System (ADS)

    Still, Tim; Sainidou, Rebecca; Hellmann, Goetz; Fytas, George

    2009-03-01

    We report on the measurement of elastic vibrational modes (eigenvibrations) in silica--poly(methyl meth-acrylate) (SiO2--PMMA) core-shell spheres and corresponding spherical hollow capsules (PMMA) with different particle size (dia-meter: 232 nm--405 nm) and shell thickness (25 nm--112 nm) using Brillouin light scattering, supported by numerical calculations. [T. Still et al., Nano Lett. 8, 3194 (2008)] These localized modes allow to access the mechanical moduli of core and shell material. We observe reduced mechanical strength of the porous silica core and for the core-shell spheres a striking increase of the moduli in both the SiO2 core and the PMMA shell. The peculiar behavior of the vibrational modes in the hollow capsules is attributed to antagonistic dependence on overall size and layer thickness. The present investigation of the acoustical properties of the individual core-shell particles can lead to the use of such nanoscale engineered particles in more eloborate systems to control hypersonic phonons.

  18. Electrum, the Gold-Silver Alloy, from the Bulk Scale to the Nanoscale: Synthesis, Properties, and Segregation Rules.

    PubMed

    Guisbiers, Grégory; Mendoza-Cruz, Rubén; Bazán-Díaz, Lourdes; Velázquez-Salazar, J Jesús; Mendoza-Perez, Rafael; Robledo-Torres, José Antonio; Rodriguez-Lopez, José-Luis; Montejano-Carrizales, Juan Martín; Whetten, Robert L; José-Yacamán, Miguel

    2016-01-26

    The alloy Au-Ag system is an important noble bimetallic phase, both historically (as "Electrum") and now especially in nanotechnology, as it is applied in catalysis and nanomedicine. To comprehend the structural characteristics and the thermodynamic stability of this alloy, a knowledge of its phase diagram is required that considers explicitly its size and shape (morphology) dependence. However, as the experimental determination remains quite challenging at the nanoscale, theoretical guidance can provide significant advantages. Using a regular solution model within a nanothermodynamic approach to evaluate the size effect on all the parameters (melting temperature, melting enthalpy, and interaction parameters in both phases), the nanophase diagram is predicted. Besides an overall shift downward, there is a "tilting" effect on the solidus-liquidus curves for some particular shapes exposing the (100) and (110) facets (cube, rhombic dodecahedron, and cuboctahedron). The segregation calculation reveals the preferential presence of silver at the surface for all the polyhedral shapes considered, in excellent agreement with the latest transmission electron microscopy observations and energy dispersive spectroscopy analysis. By reviewing the nature of the surface segregated element of different bimetallic nanoalloys, two surface segregation rules, based on the melting temperatures and surface energies, are deduced. Finally, the optical properties of Au-Ag nanoparticles, calculated within the discrete dipole approximation, show the control that can be achieved in the tuning of the local surface plasmon resonance, depending of the alloy content, the chemical ordering, the morphology, the size of the nanoparticle, and the nature of the surrounding environment. PMID:26605557

  19. Dynamic Mechanical Properties, Crystallization Behavior and Morphology of Nanoscale Tin Fluorophosphate Glass/Polyamide 66 Hybrid Materials.

    PubMed

    Liu, Huiwen; Yang, Jing; Yu, Honglin; Zou, Xiaoxuan; Jing, Bo; Dai, Wenli

    2016-04-01

    The dynamic mechanical properties, crystallization behavior and morphology of nanoscale Tg tin fluorophosphate glass (TFP glass)/polyamide 66 (PA66) hybrid materials were investigated by XRD, DSC and SEM. The experimental results showed that the Tg of TFP/PA66 hybrid decreased and the third relaxation in the highly filled hybrid appeared due to the interaction between the TFP glass and amide groups of PA66. The storage modulus of the hybrid materials increased with increase in the content of TFP at low temperatures but had little effect at high temperatures. This result was attributed to the stiffness depression of the TFP glass when the temperature rose above its Tg and the similar elasticity of the two phases because of the interaction between the components. The degree of crystallinity and a, y crystal content of PA66 both decreased due to the interaction between the two phases. In addition, the phase defect, the size distribution and the compatibility of TFP in the PA66 matrix were discussed by SEM, the results showed that the TFP appeared aggregation partly, but had the favorable compatibility in the PA66 matrix. PMID:27451779

  20. The boron oxide{endash}boric acid system: Nanoscale mechanical and wear properties

    SciTech Connect

    Ma, X.; Unertl, W.N.; Erdemir, A.

    1999-08-01

    The film that forms spontaneously when boron oxide (B{sub 2}O{sub 3}) is exposed to humid air is a solid lubricant. This film is usually assumed to be boric acid (H{sub 3}BO{sub 3}), the stable bulk phase. We describe the nanometer-scale surface morphology, mechanical properties, and tribological properties of these films and compare them with crystals precipitated from saturated solutions of boric acid. Scanning force microscopy (SFM) and low-load indentation were the primary experimental tools. Mechanical properties and their variation with depth are reported. In all cases, the surfaces were covered with a layer that has different mechanical properties than the underlying bulk. The films formed on boron oxide showed no evidence of crystalline structure. A thin surface layer was rapidly removed, followed by slower wear of the underlying film. The thickness of this initial layer was sensitive to sample preparation conditions, including humidity. Friction on the worn surface was lower than on the as-formed surface in all cases. In contrast, the SFM tip was unable to cause any wear to the surface film on the precipitated crystals. Indentation pop-in features were common for precipitated crystals but did not occur on the films formed on boron oxide. The surface structures were more complex than assumed in models put forth previously to explain the mechanism of lubricity in the boron oxide{endash}boric acid{endash}water system. {copyright} {ital 1999 Materials Research Society.}

  1. Exposure, Health and Ecological Effects Review of Engineered Nanoscale Cerium and Cerium Oxide Associated with its Use as a Fuel Additive

    EPA Science Inventory

    Advances of nanoscale science have produced nanomaterials with unique physical and chemical properties at commercial levels which are now incorporated into over 1000 products. Nanoscale cerium (di) oxide (CeO(2)) has recently gained a wide range of applications which includes coa...

  2. Exposure and Health Effects Review of Engineered Nanoscale Cerium and Cerium Dioxide Associated with its Use as a Fuel Additive - NOW IN PRINT IN THE JOURNAL

    EPA Science Inventory

    Advances of nanoscale science have produced nanomaterials with unique physical and chemical properties at commercial levels that are now incorporated into over 1000 products. Nanoscale cerium (di) oxide (Ce02) has recently gained a wide range of applications which includes coatin...

  3. 40 CFR 716.50 - Reporting physical and chemical properties.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... chemical properties. Studies of physical and chemical properties must be reported under this subpart if... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Reporting physical and chemical properties. 716.50 Section 716.50 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED)...

  4. Electronic properties of organic thin film transistors with nanoscale tapered electrodes

    NASA Astrophysics Data System (ADS)

    Park, Jeongwon

    2008-10-01

    Organic thin-film transistors (OTFTs) have received increasing attention because of their potential applications in displays, optoelectronics, logic circuits, and sensors. Ultrathin OTFTs are of technical interest as a possible route toward reduced bias stress in standard OTFTs and enhanced sensitivity in chemical field-effect transistors (ChemFETs). ChemFETs are OTFTs whose output characteristics are sensitive to the presence of analytes via changes in the channel mobility and/or threshold voltage induced by analyte chemisorption onto the channel materials. The fundamental understanding of charge transport properties of organic thin-films is critical for the applications. OTFT has been demonstrated by many groups; however, there has been much less progress towards more reliable contact structure between organic materials and electrodes. This thesis investigates the electrical properties of metal phthalocyanine thin-film devices. In chapter 1, the basic electrical properties in OTFTs are reviewed. In chapter 2, we have investigated the microfabrication process of OTFTs to control the contact morphology and the charge transport properties of phthalocyanine thin-film devices. In chapter 3, the channel thickness dependence of the mobility was investigated in bottom-contact copper phthalocyanine (CuPc) OTFTs. The current-voltage characteristics of bottom contact CuPc OTFTs with low contact resistance fabricated by the bilayer photoresist lift-off process were analyzed to determine the mobility, threshold voltage and contact resistance. The independence of measured electronic properties from channel thickness is due to the contact resistance being negligible for all channel thicknesses. For practical applications, the aging and recovery process in CuPc OTFTs were investigated in chapter 4. An origin of the aging process on CuPc OTFTs has been investigated based on the responses of thick 1000ML CuPc OTFTs under a controlled atmosphere. The recovery process under 30

  5. Dynamic structural disorder in supported nanoscale catalysts

    SciTech Connect

    Rehr, J. J.; Vila, F. D.

    2014-04-07

    We investigate the origin and physical effects of “dynamic structural disorder” (DSD) in supported nano-scale catalysts. DSD refers to the intrinsic fluctuating, inhomogeneous structure of such nano-scale systems. In contrast to bulk materials, nano-scale systems exhibit substantial fluctuations in structure, charge, temperature, and other quantities, as well as large surface effects. The DSD is driven largely by the stochastic librational motion of the center of mass and fluxional bonding at the nanoparticle surface due to thermal coupling with the substrate. Our approach for calculating and understanding DSD is based on a combination of real-time density functional theory/molecular dynamics simulations, transient coupled-oscillator models, and statistical mechanics. This approach treats thermal and dynamic effects over multiple time-scales, and includes bond-stretching and -bending vibrations, and transient tethering to the substrate at longer ps time-scales. Potential effects on the catalytic properties of these clusters are briefly explored. Model calculations of molecule-cluster interactions and molecular dissociation reaction paths are presented in which the reactant molecules are adsorbed on the surface of dynamically sampled clusters. This model suggests that DSD can affect both the prefactors and distribution of energy barriers in reaction rates, and thus can significantly affect catalytic activity at the nano-scale.

  6. Dynamic structural disorder in supported nanoscale catalysts.

    PubMed

    Rehr, J J; Vila, F D

    2014-04-01

    We investigate the origin and physical effects of "dynamic structural disorder" (DSD) in supported nano-scale catalysts. DSD refers to the intrinsic fluctuating, inhomogeneous structure of such nano-scale systems. In contrast to bulk materials, nano-scale systems exhibit substantial fluctuations in structure, charge, temperature, and other quantities, as well as large surface effects. The DSD is driven largely by the stochastic librational motion of the center of mass and fluxional bonding at the nanoparticle surface due to thermal coupling with the substrate. Our approach for calculating and understanding DSD is based on a combination of real-time density functional theory/molecular dynamics simulations, transient coupled-oscillator models, and statistical mechanics. This approach treats thermal and dynamic effects over multiple time-scales, and includes bond-stretching and -bending vibrations, and transient tethering to the substrate at longer ps time-scales. Potential effects on the catalytic properties of these clusters are briefly explored. Model calculations of molecule-cluster interactions and molecular dissociation reaction paths are presented in which the reactant molecules are adsorbed on the surface of dynamically sampled clusters. This model suggests that DSD can affect both the prefactors and distribution of energy barriers in reaction rates, and thus can significantly affect catalytic activity at the nano-scale. PMID:24712802

  7. Thermomechanical properties of Ni-Ti shape memory wires containing nanoscale precipitates induced by stress-assisted ageing.

    PubMed

    Cong, D Y; Saha, G; Barnett, M R

    2014-12-01

    This paper systematically examines the thermomechanical properties and phase transformation behaviour of slightly Ni-rich Ni-Ti biomedical shape memory wires containing homogeneously distributed nanoscale precipitates induced by stress-assisted ageing. In contrast to previous studies, particular attention is paid to the role of precipitates in impeding twin boundary movement (TBM) and its underlying mechanisms. The size and volume fraction of precipitates are altered by changing the ageing time. The martensitic transformation temperatures increase with prolonged ageing time, whereas the R-phase transformation temperature remains relatively unchanged. The stress-strain behaviour in different phase regions during both cooling and heating is comprehensively examined, and the underlying mechanisms for the temperature- and thermal-history-dependent behaviour are elucidated with the help of the established stress-temperature phase diagram. The effect of precipitates on TBM is explored by mechanical testing at 133K. It is revealed that the critical stress for TBM (σcr) increases with increasing ageing time. There is a considerable increase of 104MPa in σcr in the sample aged at 773K for 120min under 70MPa compared with the solution-treated sample, owing to the presence of precipitates. The Orowan strengthening model of twinning dislocations is insufficient to account for this increase in σcr. The back stress generation is the predominant mechanism for the interactions between precipitates and twin boundaries during TBM that give rise to the increase in σcr. Such results provide new insights into the thermomechanical properties of precipitate containing Ni-Ti biomedical shape memory wires, which are instructive for developing high-performance biomedical shape memory alloys. PMID:25159371

  8. Electrical and Optical Properties of CeNi5 Nanoscale Films

    NASA Astrophysics Data System (ADS)

    Todoran, Radu; Todoran, Daniela; Racolta, Dania; Szakács, Zsolt

    2016-05-01

    Rare earth compounds are interesting from both a theoretical point of view and for their applications. That is the reason why determining their optical and electrical properties deserves special attention. In this article, we present the conditions we obtained homogenous CeNi5 thin films of nanometer thicknesses. To achieve this goal, our method of choice was laser-induced vaporization, using short and modulated impulses, with electro-optical tuning for the quality factor. The layers that were deposited at a single laser burst had thicknesses between 1.5 and 2.5 nm, depending on the geometry of the experimental setup.

  9. Nanoscale Piezoelectric Properties of Self-Assembled Fmoc-FF Peptide Fibrous Networks.

    PubMed

    Ryan, Kate; Beirne, Jason; Redmond, Gareth; Kilpatrick, Jason I; Guyonnet, Jill; Buchete, Nicolae-Viorel; Kholkin, Andrei L; Rodriguez, Brian J

    2015-06-17

    Fibrous peptide networks, such as the structural framework of self-assembled fluorenylmethyloxycarbonyl diphenylalanine (Fmoc-FF) nanofibrils, have mechanical properties that could successfully mimic natural tissues, making them promising materials for tissue engineering scaffolds. These nanomaterials have been determined to exhibit shear piezoelectricity using piezoresponse force microscopy, as previously reported for FF nanotubes. Structural analyses of Fmoc-FF nanofibrils suggest that the observed piezoelectric response may result from the noncentrosymmetric nature of an underlying β-sheet topology. The observed piezoelectricity of Fmoc-FF fibrous networks is advantageous for a range of biomedical applications where electrical or mechanical stimuli are required. PMID:25994251

  10. Physical properties of molten lithium tetraborate

    NASA Astrophysics Data System (ADS)

    Anzai, Y.; Terashima, K.; Kimura, S.

    1993-12-01

    The physical properties of molten Li2B4O7 were studied for growing high-quality single crystals. We found that the density, θ, surface tension, λ, and volume thermal expansion coefficient of the melt, β, varied as θ=2.444-0.000414 T g/cm 3, λ=249-0.045 T mN/m and β = 2.1 x 10 -4 K -1, respectively, for temperatures of 1190 to 1373 K. The temperature dependence of the viscosity did not show a simple exponential relationship. It was found that the flow unit volume at the melting point (1190 K) was 10 times larger than that at 1373 K. The viscosity and density displayed relaxation after the starting material was completely melted, showing that a minimum of 15 h was required for the melt to become stable at 1223 K. Our results suggest that for growing high-quality Li 2B 4O 7 single crystals the melt should be held more than 15 h before the pulling process is started.

  11. Physical properties of defined lipopolysaccharide salts

    SciTech Connect

    Coughlin, R.T.; Haug, A.; McGroarty, E.J.

    1983-01-01

    The electron spin resonance probes 5-doxylstearate and 4-(dodecyldimethylammonia)-1-oxy-2,2,6,6-tetramethylpiperidine bromide were used to characterize the fluidity of the acyl chain and head-group regions, respectively, of defined salts of lipopolysaccharide (LPS) from Escherichia coli K12. The removal of the weakly bound divalent cations from native LPS by electrodialysis and their replacement by sodium had little effect on the midpoint of the lipid-phase transition or on head-group mobility. In contrast, lipopolysaccharide acyl chain mobility increased following electrodialysis. The replacement of most of the remaining cations with sodium resulted in a further dramatic increase in mobility in both the polar and nonpolar regions of lipopolysaccharide. Head-group mobility of the sodium salt of LPS was shown to be reduced with the addition of divalent cations. Furthermore, evidence is presented which suggests that low magnesium concentrations may induce phase separations in the sodium salt. The magnesium salt of lipopolysaccharide closely resembled the native form in both head-group and acyl chain mobility although the cation charge to phosphorus ratio in the magnesium salt was greater than that detected in the native isolate. Analyses of other lipopolysaccharide salts support our hypothesis that many of the observed differences in the physical and pathological properties of lipopolysaccharide salts may simply be explained by the degree of charge neutralization.

  12. Physical properties of Planck Cold Dust Clumps

    NASA Astrophysics Data System (ADS)

    Wu, Y.; Liu, T.; Meng, F.; Yuan, J.; Zhang, T.; Chen, P.; Hu, R.; Li, D.; Qin, S.; Ju, B.

    2016-05-01

    To explore physical properties of Planck cold dust clumps, 674 of the pilot samples were observed at the 13.7 m telescope of Purple Mountain Observatory (PMO) in J = 1 - 0 transitions of CO, 13CO and C18O. HCO+, HCN and N2H+ emissions were also observed with PMO 13.7 m and IRAM 30 m telescopes. They are real cold and quiescent with mean Tk ˜ 10 K and mean FWHM of 13CO (1-0) 1.27 km s-1. Column density ranges from 1020 to 1022 cm-2. Gas of the Planck clumps extends molecular space in the Milky Way. Turbulence dominates in cores. Filament structure is the majority and most of the cores are starless. Ten percent of the cores show asymmetric emission features including blue- and red- profiles. Planck clumps include different cold or low luminosity sources. Dense cores constitute an ideal sample for studying initial state of star formation while the diffuse clumps are suitable for investigating the formation of cores.

  13. Physical properties of molten carbonate electrolyte

    SciTech Connect

    Kojima, T.; Yanagida, M.; Tanimoto, K.

    1996-12-31

    Recently many kinds of compositions of molten carbonate electrolyte have been applied to molten carbonate fuel cell in order to avoid the several problems such as corrosion of separator plate and NiO cathode dissolution. Many researchers recognize that the addition of alkaline earth (Ca, Sr, and Ba) carbonate to Li{sub 2}CO{sub 3}-Na{sub 2}CO{sub 3} and Li{sub 2}CO{sub 3}-K{sub 2}CO{sub 3} eutectic electrolytes is effective to avoid these problems. On the other hand, one of the corrosion products, CrO{sub 4}{sup 2-} ion is found to dissolve into electrolyte and accumulated during the long-term MCFC operations. This would affect the performance of MCFC. There, however, are little known data of physical properties of molten carbonate containing alkaline earth carbonates and CrO{sub 4}{sup 2-}. We report the measured and accumulated data for these molten carbonate of electrical conductivity and surface tension to select favorable composition of molten carbonate electrolytes.

  14. Physical properties of defined lipopolysaccharide salts.

    PubMed

    Coughlin, R T; Haug, A; McGroarty, E J

    1983-04-12

    The electron spin resonance probes 5-doxylstearate and 4-(dodecyldimethylammonio)-1-oxy-2,2,6,6-tetramethylpiperidine bromide were used to characterize the fluidity of the acyl chain and head-group regions, respectively, of defined salts of lipopolysaccharide (LPS) from Escherichia coli K12. The removal of the weakly bound divalent cations from native LPS by electrodialysis and their replacement by sodium had little effect on the midpoint of the lipid-phase transition or on head-group mobility. In contrast, lipopolysaccharide acyl chain mobility increased following electrodialysis. The replacement of most of the remaining cations with sodium resulted in a further dramatic increase in mobility in both the polar and nonpolar regions of lipopolysaccharide. Head-group mobility of the sodium salt of LPS was shown to be reduced with the addition of divalent cations. Furthermore, evidence is presented which suggests that low magnesium concentrations may induce phase separations in the sodium salt. The magnesium salt of lipopolysaccharide closely resembled the native form in both head-group and acyl chain mobility although the cation charge to phosphorus ratio in the magnesium salt was greater than that detected in the native isolate. Analyses of other lipopolysaccharide salts support our hypothesis that many of the observed differences in the physical and pathological properties of lipopolysaccharide salts may simply be explained by the degree of charge neutralization. PMID:6303400

  15. Tuning the Optical Properties of Mesoporous TiO2 Films by Nanoscale Engineering

    SciTech Connect

    Schwenzer, Birgit; Wang, Liang; Swensen, James S.; Padmaperuma, Asanga B.; Silverman, Gary; Korotkov, Roman; Gaspar, Daniel J.

    2012-07-03

    Introducing mesoscale pores into spincoated titanium dioxide films, prepared by spincoating different sol-gel precursor solutions on silicon substrates and subsequent annealing at 350 C, 400 C or 450 C, respectively, affects several optical properties of the material. The change in refractive index observed for different mesoporous anatase films directly correlates with changes in pore size, but is also in a more complex manner influenced by the film thickness and the density of pores within the films. Additionally, the band gap of the films is blueshifted by the stress the introduction of pores exerts on the inorganic matrix. The differently sized pores were templated by Pluronic{reg_sign} block copolymers in the solgel solutions and tuned by employing different annealing temperatures for the film preparation. This study focused on elucidating the effect different templating materials (F127 and P123) have on the pore size of the final mesoporous titania film, and on understanding the relation of varying polymer concentration (taking P123 as an example) in the sol-gel solution to the pore concentration and size in the resultant titania film. Titania thin film samples or corresponding titanium dioxide powders were characterized by X-ray diffraction, nitrogen adsorption, ellipsometery, UV/Vis spectrometry and other techniques to understand the interplay between mesoporosity and optical properties.

  16. Synthesis, structure, and opto-electronic properties of organic-based nanoscale heterojunctions

    PubMed Central

    2011-01-01

    Enormous research effort has been put into optimizing organic-based opto-electronic systems for efficient generation of free charge carriers. This optimization is mainly due to typically high dissociation energy (0.1-1 eV) and short diffusion length (10 nm) of excitons in organic materials. Inherently, interplay of microscopic structural, chemical, and opto-electronic properties plays crucial role. We show that employing and combining advanced scanning probe techniques can provide us significant insight into the correlation of these properties. By adjusting parameters of contact- and tapping-mode atomic force microscopy (AFM), we perform morphologic and mechanical characterizations (nanoshaving) of organic layers, measure their electrical conductivity by current-sensing AFM, and deduce work functions and surface photovoltage (SPV) effects by Kelvin force microscopy using high spatial resolution. These data are further correlated with local material composition detected using micro-Raman spectroscopy and with other electronic transport data. We demonstrate benefits of this multi-dimensional characterizations on (i) bulk heterojunction of fully organic composite films, indicating differences in blend quality and component segregation leading to local shunts of photovoltaic cell, and (ii) thin-film heterojunction of polypyrrole (PPy) electropolymerized on hydrogen-terminated diamond, indicating covalent bonding and transfer of charge carriers from PPy to diamond. PMID:21711759

  17. Synthesis, structure, and opto-electronic properties of organic-based nanoscale heterojunctions

    NASA Astrophysics Data System (ADS)

    Rezek, Bohuslav; Čermák, Jan; Kromka, Alexander; Ledinský, Martin; Hubík, Pavel; Mareš, Jiří J.; Purkrt, Adam; Cimrová, Vĕra; Fejfar, Antonín; Kočka, Jan

    2011-12-01

    Enormous research effort has been put into optimizing organic-based opto-electronic systems for efficient generation of free charge carriers. This optimization is mainly due to typically high dissociation energy (0.1-1 eV) and short diffusion length (10 nm) of excitons in organic materials. Inherently, interplay of microscopic structural, chemical, and opto-electronic properties plays crucial role. We show that employing and combining advanced scanning probe techniques can provide us significant insight into the correlation of these properties. By adjusting parameters of contact- and tapping-mode atomic force microscopy (AFM), we perform morphologic and mechanical characterizations (nanoshaving) of organic layers, measure their electrical conductivity by current-sensing AFM, and deduce work functions and surface photovoltage (SPV) effects by Kelvin force microscopy using high spatial resolution. These data are further correlated with local material composition detected using micro-Raman spectroscopy and with other electronic transport data. We demonstrate benefits of this multi-dimensional characterizations on (i) bulk heterojunction of fully organic composite films, indicating differences in blend quality and component segregation leading to local shunts of photovoltaic cell, and (ii) thin-film heterojunction of polypyrrole (PPy) electropolymerized on hydrogen-terminated diamond, indicating covalent bonding and transfer of charge carriers from PPy to diamond.

  18. Correlating the nanoscale mechanical and chemical properties of knockout mice bones

    NASA Astrophysics Data System (ADS)

    Kavukcuoglu, Nadire Beril

    Bone is a mineral-organic composite where the organic matrix is mainly type I collagen plus small amounts of non-collagenous proteins including osteopontin (OPN), osteocalcin (OC) and fibrillin 2 (Fbn2). Mature bone undergoes remodeling continually so new bone is formed and old bone resorbed. Uncoupling between the bone resorption and bone formation causes an overall loss of bone mass and leads to diseases like osteoporosis and osteopenia. These are characterized by structural deterioration of the bone tissue and an increased risk of fracture. The non-collagenous bone proteins are known to have a role in regulating bone turnover and to affect the structural integrity of bone. OPN and OC play a key role in bone resorption and formation, while absence of Fbn-2 causes a connective tissue disorder (congenital contractural arachnodactyly) and has been associated with decreased bone mass. In this thesis nanoindentation and Raman-microspectroscopy techniques were used to investigate and correlate the mechanical and chemical properties of cortical femoral bones from OPN deficient (OPN-/-), OC deficient (OC-/-) and Fbn-2 deficient (Fbn2-/-) mice and their age, sex and background matched wild-type controls (OPN+/+, OC+/+ and Fbn2+/+). For OPN the hardness (H) and elastic modulus (E) of under 12 week OPN-/- bones were significantly lower than for OPN+/+ bones, but Raman showed no significant difference. Mechanical properties of bones from mice older than 12 weeks were not significantly different with genotype. However, mineralization and crystallinity from >50 week OPN-/- bones were significantly higher than for OPN+/+ bones. Mechanical properties of OPN-/- bones showed no variation with age, but mineralization, crystallinity and type-B carbonate substitution increased for both genotypes. For OC-/- intra-bone analyses showed that the hardness and crystallinity of the bones were significantly higher, especially in the mid-cortical sections, compared to OC+/+ bones. Fbn2

  19. Noble metals on the nanoscale: optical and photothermal properties and some applications in imaging, sensing, biology, and medicine.

    PubMed

    Jain, Prashant K; Huang, Xiaohua; El-Sayed, Ivan H; El-Sayed, Mostafa A

    2008-12-01

    Noble metal nanostructures attract much interest because of their unique properties, including large optical field enhancements resulting in the strong scattering and absorption of light. The enhancement in the optical and photothermal properties of noble metal nanoparticles arises from resonant oscillation of their free electrons in the presence of light, also known as localized surface plasmon resonance (LSPR). The plasmon resonance can either radiate light (Mie scattering), a process that finds great utility in optical and imaging fields, or be rapidly converted to heat (absorption); the latter mechanism of dissipation has opened up applications in several new areas. The ability to integrate metal nanoparticles into biological systems has had greatest impact in biology and biomedicine. In this Account, we discuss the plasmonic properties of gold and silver nanostructures and present examples of how they are being utilized for biodiagnostics, biophysical studies, and medical therapy. For instance, taking advantage of the strong LSPR scattering of gold nanoparticles conjugated with specific targeting molecules allows the molecule-specific imaging and diagnosis of diseases such as cancer. We emphasize in particular how the unique tunability of the plasmon resonance properties of metal nanoparticles through variation of their size, shape, composition, and medium allows chemists to design nanostructures geared for specific bio-applications. We discuss some interesting nanostructure geometries, including nanorods, nanoshells, and nanoparticle pairs, that exhibit dramatically enhanced and tunable plasmon resonances, making them highly suitable for bio-applications. Tuning the nanostructure shape (e.g., nanoprisms, nanorods, or nanoshells) is another means of enhancing the sensitivity of the LSPR to the nanoparticle environment and, thereby, designing effective biosensing agents. Metal nanoparticle pairs or assemblies display distance-dependent plasmon resonances as a

  20. A training effect on electrical properties in nanoscale BiFeO3.

    PubMed

    Goswami, Sudipta; Bhattacharya, Dipten; Li, Wuxia; Cui, Ajuan; Jiang, QianQing; Gu, Chang-zhi

    2013-04-01

    We report our observation of the training effect on dc electrical properties in a nanochain of BiFeO3 as a result of large scale migration of defects under the combined influence of electric field and Joule heating. We show that an optimum number of cycles of electric field within the range zero to ~1.0 MV cm(-1) across a temperature range 80-300 K helps in reaching the stable state via a glass-transition-like process in the defect structure. Further treatment does not give rise to any substantial modification. We conclude that such a training effect is ubiquitous in pristine nanowires or chains of oxides and needs to be addressed for applications in nanoelectronic devices. PMID:23478468

  1. Tailoring nanoscale properties of tungsten oxide for inkjet printed electrochromic devices.

    PubMed

    Wojcik, Pawel Jerzy; Santos, Lidia; Pereira, Luis; Martins, Rodrigo; Fortunato, Elvira

    2015-02-01

    This paper focuses on the engineering procedures governing the synthesis of tungsten oxide nanocrystals and the formulation of printable dispersions for electrochromic applications. By that means, we aim to stress the relevancy of a proper design strategy that results in improved physicochemical properties of nanoparticle loaded inks. In the present study inkjet printable nanostructured tungsten oxide particles were successfully synthesized via hydrothermal processes using pure or acidified aqueous sol-gel precursors. Based on the proposed scheme, the structure and morphology of the nanoparticles were tailored to ensure the desired printability and electrochromic performance. The developed nanomaterials with specified structures effectively improved the electrochemical response of printed films, resulting in 2.5 times higher optical modulation and 2 times faster coloration time when compared with pure amorphous films. PMID:25384683

  2. Tailoring nanoscale properties of tungsten oxide for inkjet printed electrochromic devices

    NASA Astrophysics Data System (ADS)

    Wojcik, Pawel Jerzy; Santos, Lidia; Pereira, Luis; Martins, Rodrigo; Fortunato, Elvira

    2015-01-01

    This paper focuses on the engineering procedures governing the synthesis of tungsten oxide nanocrystals and the formulation of printable dispersions for electrochromic applications. By that means, we aim to stress the relevancy of a proper design strategy that results in improved physicochemical properties of nanoparticle loaded inks. In the present study inkjet printable nanostructured tungsten oxide particles were successfully synthesized via hydrothermal processes using pure or acidified aqueous sol-gel precursors. Based on the proposed scheme, the structure and morphology of the nanoparticles were tailored to ensure the desired printability and electrochromic performance. The developed nanomaterials with specified structures effectively improved the electrochemical response of printed films, resulting in 2.5 times higher optical modulation and 2 times faster coloration time when compared with pure amorphous films.This paper focuses on the engineering procedures governing the synthesis of tungsten oxide nanocrystals and the formulation of printable dispersions for electrochromic applications. By that means, we aim to stress the relevancy of a proper design strategy that results in improved physicochemical properties of nanoparticle loaded inks. In the present study inkjet printable nanostructured tungsten oxide particles were successfully synthesized via hydrothermal processes using pure or acidified aqueous sol-gel precursors. Based on the proposed scheme, the structure and morphology of the nanoparticles were tailored to ensure the desired printability and electrochromic performance. The developed nanomaterials with specified structures effectively improved the electrochemical response of printed films, resulting in 2.5 times higher optical modulation and 2 times faster coloration time when compared with pure amorphous films. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr05765a

  3. Probing Nanoscale Pentacene Films by Resonant Raman Scattering

    NASA Astrophysics Data System (ADS)

    He, Rui; Dujovne, Irene; Chen, Liwei; Miao, Qian; Hirjibehedin, Cyrus F.; Pinczuk, Aron; Nuckolls, Colin; Kloc, Christian; Blanchet, Graciela B.

    2005-06-01

    Resonant enhancements of Raman scattering intensities offer the sensitivity required to study nanoscale pentacene films that reach into monolayer thickness. In the results reported here structural characterization of ultra-thin layers and of their fundamental optical properties are investigated by resonant Raman scattering from intra-molecular and inter-molecular vibrations. In this work Raman methods emerge as ideal tools for the study of physics and characterization of ultra-thin nanoscale films of molecular organic materials fabricated on diverse substrates of current and future devices.

  4. Nano-scale Studies of the Assembly, Structure and Properties of Hybrid Organic-Silicon Systems

    NASA Astrophysics Data System (ADS)

    Sinha, Shoma

    Advancements in the field of electronics might be achieved by future molecular scale devices. Hybrid organic-silicon structures have the potential to overcome many challenges facing the use of molecules as devices while maintaining the ability to interface with traditional silicon technology. The objective of this dissertation was to advance our base knowledge of the interactions, behaviour and properties of simple molecular systems and the Si(100):2 × 1 surface. Experimental studies conducted with scanning tunneling microscopy (STM) and complemented with theoretical investigations, primarily density functional theory (DFT), were utilized to investigate three principle areas of interest: (1) the transport behaviour of monolayers, patterned regions, or nanostructures, (2) surface diffusion and (3) properties of self-assembled molecular lines. The tunneling current versus applied bias behaviour of the clean, the monohydride and the styrene passivated Si(100):2 × 1 surfaces were studied. An energy band model was formed that incorporates surface dipole characteristics and band bending to describe tunneling current transport. The transport behaviour from patterns of clean, styrene covered, and 4-fluorostyrene covered Si(100):2 × 1 on otherwise monohydride terminated Si(100):2 × 1 were subsequently studied. Comparison with the observations from the full monolayers provided evidence for conduction through surface states. Studies of the transport behaviour of styrene molecular lines were also performed. Surface diffusion is an important aspect of self-assembly. A novel experimental method for studying aspects of diffusion that removes STM tip effects was developed and used to study the diffusion anisotropy of styrene and 4-uorostyrene on HSi( 100):2 × 1. These studies were complemented with DFT energy calculations and Monte Carlo methods to incorporate dynamic effects. Various studies were conducted on self-assembled molecular lines. In addition to studying the

  5. Nano-scale thermal property prediction by molecular dynamics simulation with experimental validation

    NASA Astrophysics Data System (ADS)

    Horne, Kyle S.

    Quantum cascade laser (QCL) diodes have potential applications in many areas including emissions analysis and explosives detection, but like many solid-state devices they suffer from degraded performance at higher temperatures. To alleviate this drawback, the thermal properties of the QCL diodes must be better understood. Using molecular dynamics (MD) and photothermal radiometry (PTR), the thermal conductivity of a representative QCL diode is computed and measured respectively. The MD results demonstrate that size effects are present in the simulated systems, but if these are accounted for by normalization to experimental results the thermal conductivity of the QCL can be reasonably obtained. The cross-plane conductivity is found to be in the range of 1.8 to 4.3 W/m ˙ K, while the in-plane results are in the range of 3.7 to 4.0 W/m ˙ K. These values compare well with experimental results from the literature for both QCL materials and for AlInAs and GaInAs, which the QCL is composed of. The cross-plane conductivity results are lower than those of either AlInAs or GaInAs, which demonstrates the phonon scattering at the interfaces. The in-plane results are between AlInAs and GaInAs, which is to be expected. The PTR results are less concrete, as there seem to be heat transfer effects active in the samples which are not included in the models used to fit the frequency scans. These effects are not 2D heat transfer artifacts nor are they the result of volumetric absorption. It is possible that they are the results of plasmon induction, but this is only supposition. As the data stand, the PTR and MD results are within an order of magnitude of each other and follow reasonable trends, which suggests that both results are not too far off from reality. While the experimental results are not entirely conclusive, the simulations and experiments corroborate each other sufficiently to warrant further investigation using these techniques. Additionally, the simulations present

  6. Magnetic properties of nanoscale crystalline maghemite obtained by a new synthetic route

    NASA Astrophysics Data System (ADS)

    Mercante, L. A.; Melo, W. W. M.; Granada, M.; Troiani, H. E.; Macedo, W. A. A.; Ardison, J. D.; Vaz, M. G. F.; Novak, M. A.

    2012-09-01

    In this work we describe the synthesis and characterization of maghemite nanoparticles obtained by a new synthetic route. The material was synthesized using triethylamine as a coprecipitation agent in the presence of the organic ligand N,N‧-bis(3,5-di-tert-butyl-catechol)-2,4-diaminotoluene (LCH3). Mössbauer spectrum at 4 K shows typical hyperfine parameters of maghemite and Transmission Electron Microscopy images reveal that the nanoparticles have a mean diameter of 3.9 nm and a narrow size distribution. AC magnetic susceptibility in zero field presents an Arrhenius behavior with unreasonable relaxation parameters due to the strong influence of dipolar interaction. In contrast when the measurements are performed in a 1 kOe field, the effect of dipolar interactions becomes negligible and the obtained parameters are in good agreement with the static magnetic properties. The dynamic energy barrier obtained from the AC susceptibility results is larger than the expected from the average size observed by HRTEM results, evidencing the strong influence of the surface contribution to the anisotropy.

  7. The nanoscale mechanical properties of nickel-titanium shape memory alloy

    NASA Astrophysics Data System (ADS)

    Shaw, Gordon A., III

    Shape memory alloys (SMAs) are a class of metal alloys which can recover large amounts of strain through a solid-state phase change known as a martensitic transformation. Nickel titanium is the most well-known of these alloys, and although it is widely used, relatively little is known about its potential for use in nanotechnology. This thesis contains research designed to examine the mechanical properties of nickel titanium at the nanometer scale, and determine its suitability for use in nanotechnology applications. Results from nanoindentation-atomic force microscopy experiments show indentations in the surface of nickel titanium thin films can recover by the thermally induced shape memory effect. This process is explained in the context of a new model based on the expanding spherical cavity model, which can also be used to predict the onset of substrate effects during indentation. A new digital information storage device based on this phenomenon will also be discussed. Finally, the fabrication and characterization of mechanically active nickel titanium nanoparticles is presented. The research presented indicates that nickel titanium shape memory alloy is quite suitable for nanotechnology applications.

  8. Buff/wipe effects on the physicochemical properties of perfluoropolyether nanoscale thin films

    NASA Astrophysics Data System (ADS)

    Chen, Haigang; Seung Chung, Pil; Jhon, Myung S.

    2014-05-01

    Buff/Wipe (B/W) process is commonly used in disk drive manufacturing to remove the particles and asperities on the lubricated disk surface. In this paper, we investigated how B/W process impacts the physicochemical properties of perfluoropolyethers (PFPE) nano-films through the study of surface energy and bonded ratio. Two-liquid geometric method was used to analyze the surface energy of nonfunctional PFPE, i.e., Z03, and functional PFPE, i.e., Zdol, lubricated media before and after B/W process. It was found that the dispersive surface energy of Z03 films greatly decreased after B/W, which was more significant in the submonolayer regime. In addition, the bonded ratio slightly increased. However, B/W effect on the surface energy and bonded ratio was not detected for Zdol films. It is hypothesized that nonfunctional PFPE behaves liquid-like on the carbon overcoat due to the weak interaction between lubricant and overcoat. External mechanical stress as applied with B/W can change the conformation and increase the surface coverage for nonfunctional PFPE. On the other hand, functional PFPEs behave solid-like due to the strong attraction between lubricant and overcoat; therefore, it is difficult to change the conformation by external stress from B/W process.

  9. Viscoelastic properties and nanoscale structures of composite oligopeptide-polysaccharide hydrogels.

    PubMed

    Hyland, Laura L; Taraban, Marc B; Feng, Yue; Hammouda, Boualem; Yu, Y Bruce

    2012-03-01

    Biocompatible and biodegradable peptide hydrogels are drawing increasing attention as prospective materials for human soft tissue repair and replacement. To improve the rather unfavorable mechanical properties of our pure peptide hydrogels, in this work we examined the possibility of creating a double hydrogel network. This network was created by means of the coassembly of mutually attractive, but self-repulsive oligopeptides within an already-existing fibrous network formed by the charged, biocompatible polysaccharides chitosan, alginate, and chondroitin. Using dynamic oscillatory rheology experiments, it was found that the coassembly of the peptides within the existing polysaccharide network resulted in a less stiff material as compared to the pure peptide networks (the elastic modulus G' decreased from 90 to 10 kPa). However, these composite oligopeptide-polysaccharide hydrogels were characterized by a greater resistance to deformation (the yield strain γ grew from 4 to 100%). Small-angle neutron scattering (SANS) was used to study the 2D cross-sectional shapes of the fibers, their dimensional characteristics, and the mesh sizes of the fibrous networks. Differences in material structures found with SANS experiments confirmed rheology data, showing that incorporation of the peptides dramatically changed the morphology of the polysaccharide network. The resulting fibers were structurally very similar to those forming the pure peptide networks, but formed less stiff gels because of their markedly greater mesh sizes. Together, these findings suggest an approach for the development of highly deformation-resistant biomaterials. PMID:21994046

  10. Viscoelastic Properties and Nano-scale Structures of Composite Oligopeptide-Polysaccharide Hydrogels

    PubMed Central

    Hyland, Laura L.; Taraban, Marc B.; Feng, Yue; Hammouda, Boualem; Yu, Y. Bruce

    2012-01-01

    Biocompatible and biodegradable peptide hydrogels are drawing increasing attention as prospective materials for human soft tissue repair and replacement. To improve the rather unfavorable mechanical properties of our pure peptide hydrogels, in this work we examined the possibility of creating a double hydrogel network. This network was created by means of the co-assembly of mutually attractive but self-repulsive oligopeptides within an already existing fibrous network formed by the charged, biocompatible polysaccharides chitosan, alginate, and chondroitin. Using dynamic oscillatory rheology experiments, it was found that the co-assembly of the peptides within the existing polysaccharide network resulted in a less stiff material as compared to the pure peptide networks (the elastic modulus G′ decreased from 90 kPa to 10 kPa). However, these composite oligopeptide-polysaccharide hydrogels were characterized by a greater resistance to deformation (the yield strain γ grew from 4 % to 100 %). Small-angle neutron scattering (SANS) was used to study the 2D cross-sectional shapes of the fibers, their dimensional characteristics and the mesh sizes of the fibrous networks. Differences in material structures found with SANS experiments confirmed rheology data showing that incorporation of the peptides dramatically changed the morphology of the polysaccharide network. The resulting fibers were structurally very similar to those forming the pure peptide networks, but formedless stiff gels because of their markedly greater mesh sizes. Together, these findings suggest an approach for the development of highly deformation-resistant biomaterials. PMID:21994046

  11. Physical properties of suspended dust in Iceland

    NASA Astrophysics Data System (ADS)

    Dagsson Waldhauserova, Pavla; Olafsson, Haraldur; Arnalds, Olafur; Skrabalova, Lenka; Sigurdardottir, Gudmunda; Branis, Martin; Hladil, Jindrich; Chadimova, Leona; Skala, Roman; Navratil, Tomas; Menar, Sibylle von Lowis of; Thorsteinsson, Throstur

    2014-05-01

    Atmospheric Dust Measurements (ADMI 2013) of one of the most active dust sources in Iceland (Mælifellsandur) were conducted during season with high precipitation on August 8th-18th, 2013. We measured mass concentrations (PM2.5 and PM10), particle size distributions in size range 0.3-10μm and number concentrations during rather small dust event. Dust samples of the event were analyzed (morpho-textural observations, optical and scanning-electron microscopy). Two TSI 8520 DustTrak Aerosol Monitors (light-scattering laser photometers that measure aerosol mass concentrations in range 0.001 to 100 mg/m3) and one TSI Optical Particle Sizer (OPS) 3330 (optical scattering from single particle up to 16 different channels - 0.3 to 10 μm - measuring particle size distribution) were used. We measured a dust event which occurred during wet and low wind/windless conditions as result of surface heating in August 2013. Maximum particle number concentration (PM~0.3-10 µm) reached 149954 particles cm-3 min-1 while mass concentration (PM<10 µm) was 1757 µg m-3 min-1. Suspended dust was very fine with the highest number of particles in size range 0.3-0.337 µm, followed by particles 1.5-5 µm in diameter. Close-to-ultrafine particle size distributions showed a significant increase in number with the severity of the dust event. Number concentrations were well correlated with mass concentrations. The mineralogy and geochemical compositions showed that glaciogenic dust contains sharp-tipped shards with bubbles and 80 % of the particulate matter is volcanic glass rich in heavy metals. Wet dust particles were mobilized within < 4 hours. Here we introduced a comprehensive study on physical properties of the Icelandic dust aerosol and the first scientific study of particle size distributions in an Icelandic dust event including findings on initiation of dust suspension.

  12. Moisture dependent physical properties of lathyrus.

    PubMed

    Kenghe, Rajendra Narayan; Nimkar, Prabhakar Manohar; Shirkole, Shivanand Shankarrao

    2013-10-01

    The moisture dependent physical properties of different lathyrus varieties namely NLK-40, Pratik and Ratan were studied at moisture content of 7.33 to 30.29, 6.75 to 29.95 and 7.90 to 30.90% (d.b.), respectively. The grain size, thousand grain weight, angle of repose, grain volume and surface area were found increased linearly. The grain size was found increased from 4.43 to 4.70, 4.96 to 5.32 and 5.08 to 5.49 mm. Thousand grain weight was found increased from 64.6 to 103.5, 69.1 to 105.3 and 85.3 to 125.6 g. The angle repose was increased from 28.3 to 35.4, 29.5 to 35.8 and 26.9 to 33.5°. The grain volume was increased from 9.13 to 10.38,11.73 to 13.24 and 12.22 to 14.15 mm(3) whereas, surface area increased from 54.78 to 62.29, 70.38 to 79.45 and 73.31 to 84.88 mm(2),respectively with the corresponding increase in moisture content, for NLK-40, Pratik and Ratan. The sphericity and porosity increased initially and then found decreased with increase in further moisture content. The bulk density values decreased linearly from 827.5 to 697.2, 851.3 to 726.3 and 856.0 to 727.4 kg/m(3). The true density values were found decreased from 1288.3 to 1074.3, 1324.0 to 1118.4 and 1277.7 to 1102.5 kg/m(3), respectively for these varieties with the corresponding increase in moisture content. PMID:24425992

  13. Electrum, the Gold–Silver Alloy, from the Bulk Scale to the Nanoscale: Synthesis, Properties, and Segregation Rules

    PubMed Central

    2015-01-01

    The alloy Au–Ag system is an important noble bimetallic phase, both historically (as “Electrum”) and now especially in nanotechnology, as it is applied in catalysis and nanomedicine. To comprehend the structural characteristics and the thermodynamic stability of this alloy, a knowledge of its phase diagram is required that considers explicitly its size and shape (morphology) dependence. However, as the experimental determination remains quite challenging at the nanoscale, theoretical guidance can provide significant advantages. Using a regular solution model within a nanothermodynamic approach to evaluate the size effect on all the parameters (melting temperature, melting enthalpy, and interaction parameters in both phases), the nanophase diagram is predicted. Besides an overall shift downward, there is a “tilting” effect on the solidus–liquidus curves for some particular shapes exposing the (100) and (110) facets (cube, rhombic dodecahedron, and cuboctahedron). The segregation calculation reveals the preferential presence of silver at the surface for all the polyhedral shapes considered, in excellent agreement with the latest transmission electron microscopy observations and energy dispersive spectroscopy analysis. By reviewing the nature of the surface segregated element of different bimetallic nanoalloys, two surface segregation rules, based on the melting temperatures and surface energies, are deduced. Finally, the optical properties of Au–Ag nanoparticles, calculated within the discrete dipole approximation, show the control that can be achieved in the tuning of the local surface plasmon resonance, depending of the alloy content, the chemical ordering, the morphology, the size of the nanoparticle, and the nature of the surrounding environment. PMID:26605557

  14. Interfacial band alignment and structural properties of nanoscale TiO2 thin films for integration with epitaxial crystallographic oriented germanium

    NASA Astrophysics Data System (ADS)

    Jain, N.; Zhu, Y.; Maurya, D.; Varghese, R.; Priya, S.; Hudait, M. K.

    2014-01-01

    We have investigated the structural and band alignment properties of nanoscale titanium dioxide (TiO2) thin films deposited on epitaxial crystallographic oriented Ge layers grown on (100), (110), and (111)A GaAs substrates by molecular beam epitaxy. The TiO2 thin films deposited at low temperature by physical vapor deposition were found to be amorphous in nature, and high-resolution transmission electron microscopy confirmed a sharp heterointerface between the TiO2 thin film and the epitaxially grown Ge with no traceable interfacial layer. A comprehensive assessment on the effect of substrate orientation on the band alignment at the TiO2/Ge heterointerface is presented by utilizing x-ray photoelectron spectroscopy and spectroscopic ellipsometry. A band-gap of 3.33 ± 0.02 eV was determined for the amorphous TiO2 thin film from the Tauc plot. Irrespective of the crystallographic orientation of the epitaxial Ge layer, a sufficient valence band-offset of greater than 2 eV was obtained at the TiO2/Ge heterointerface while the corresponding conduction band-offsets for the aforementioned TiO2/Ge system were found to be smaller than 1 eV. A comparative assessment on the effect of Ge substrate orientation revealed a valence band-offset relation of ΔEV(100) > ΔEV(111) > ΔEV(110) and a conduction band-offset relation of ΔEC(110) > ΔEC(111) > ΔEC(100). These band-offset parameters are of critical importance and will provide key insight for the design and performance analysis of TiO2 for potential high-κ dielectric integration and for future metal-insulator-semiconductor contact applications with next generation of Ge based metal-oxide field-effect transistors.

  15. Deterministic control of the quantum properties of single indium arsenide artificial atoms with indium phosphide nanoscale architectures

    NASA Astrophysics Data System (ADS)

    Kim, Danny

    This thesis presents optical spectra of single InAs quantum dots on InP with an unprecedented signal-to-noise ratio and spectral resolution that has facilitated comprehensive characterization and made a significant contribution to their understanding. InAs quantum dots on InP are the leading contenders for a variety of quantum electrooptic devices that require wavelengths in the 1.5 mum range, most notably triggered single/entangled photon sources for quantum key distribution. As of yet, spectroscopic data for InAs on InP has only provided proof of emission, but no high quality data has been available, preventing any conclusive understanding of their properties. The work presented in this thesis dramatically improves upon previous reports by key optimizations at each experimental stage: growth, processing, and optical setup. The spectra clearly resolve, for the first time, the structure within the s-shell and p-shell, with fine resolution, allowing quantitative evaluation of exciton complexes such as trions, biexcitons, and triplet states. By measuring numerous dots, the behavioral trends of these species with respect to dot geometry is deduced. Also, for the first time, magnetic-field dependent spectra are obtained for individual InAs/InP dots. A remarkable discovery was the strong relation of the exciton g-factor to dot height. This thesis also demonstrates deterministic nanometer-scale control of the quantum dot dimensions---with the goal being to exploit the structure/quantum property relation in these dots. This was accomplished by using the apex of an in-situ grown nanoscale InP pyramid as a nucleation site. The dimension of this top (001) surface on which the dot nucleates is responsive to manometer-scale changes in the pyramid base dimensions, which can be precisely controlled with lithography. The InAs grown on top of these mesas then conform to the size, where the available area can be purposely relaxed or constrained. For similar height, the resulting

  16. Spectral properties of fluctuating electromagnetic fields in a plane cavity: implication for nanoscale physics.

    PubMed

    Dorofeyev, I; Fuchs, H; Jersch, J

    2002-02-01

    Spectral power densities of fluctuating electromagnetic fields and their spatial derivatives of all orders in any point of a transparent plane gap between two media described by different complex permittivities and by different temperatures were derived on a basis of generalized Kirchhoff's law. Electromagnetic losses into the two absorbing media induced by a field of a point dipole or of point multipolelike origins situated in any place of interest at the transparent gap were determined. The corresponding electrodynamical regular Green problem for a point dipole and for point multipoles of any orders constituted by the point dipole was solved. We demonstrate ways to obtain different asymptotic cases following from our general solution including the problem for a half space, Planck's formula for black body radiation, the van der Waals forces for solids kept at different temperatures, and contributions from propagating and evanescent waves. Expressions for electromagnetic loss of a point multipole of any order in selected geometry of the problem were derived and, as an important limiting case related to problems of near field microscopy, when the multipole is situated over a half space. PMID:11863681

  17. 40 CFR 716.50 - Reporting physical and chemical properties.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Reporting physical and chemical properties. 716.50 Section 716.50 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT HEALTH AND SAFETY DATA REPORTING General Provisions § 716.50 Reporting physical and chemical properties. Studies...

  18. 40 CFR 716.50 - Reporting physical and chemical properties.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Reporting physical and chemical properties. 716.50 Section 716.50 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT HEALTH AND SAFETY DATA REPORTING General Provisions § 716.50 Reporting physical and chemical properties. Studies...

  19. 40 CFR 716.50 - Reporting physical and chemical properties.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Reporting physical and chemical properties. 716.50 Section 716.50 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT HEALTH AND SAFETY DATA REPORTING General Provisions § 716.50 Reporting physical and chemical properties. Studies...

  20. Characterization and nultivariate analysis of physical properties of processing peaches

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Characterization of physical properties of fruits represents the first vital step to ensure optimal performance of fruit processing operations and is also a prerequisite in the development of new processing equipment. In this study, physical properties of engineering significance to processing of th...

  1. Introduction to physical properties and elasticity models: Chapter 20

    USGS Publications Warehouse

    Dvorkin, Jack; Helgerud, Michael B.; Waite, William F.; Kirby, Stephen H.; Nur, Amos

    2003-01-01

    Estimating the in situ methane hydrate volume from seismic surveys requires knowledge of the rock physics relations between wave speeds and elastic moduli in hydrate/sediment mixtures. The elastic moduli of hydrate/sediment mixtures depend on the elastic properties of the individual sedimentary particles and the manner in which they are arranged. In this chapter, we present some rock physics data currently available from literature. The unreferenced values in Table I were not measured directly, but were derived from other values in Tables I and II using standard relationships between elastic properties for homogeneous, isotropic material. These derivations allow us to extend the list of physical property estimates, but at the expense of introducing uncertainties due to combining property values measured under different physical conditions. This is most apparent in the case of structure II (sII) hydrate for which very few physical properties have been measured under identical conditions.

  2. Dielectric spectroscopy at the nanoscale by atomic force microscopy: A simple model linking materials properties and experimental response

    SciTech Connect

    Miccio, Luis A. Colmenero, Juan; Kummali, Mohammed M.; Alegría, Ángel; Schwartz, Gustavo A.

    2014-05-14

    The use of an atomic force microscope for studying molecular dynamics through dielectric spectroscopy with spatial resolution in the nanometer scale is a recently developed approach. However, difficulties in the quantitative connection of the obtained data and the material dielectric properties, namely, frequency dependent dielectric permittivity, have limited its application. In this work, we develop a simple electrical model based on physically meaningful parameters to connect the atomic force microscopy (AFM) based dielectric spectroscopy experimental results with the material dielectric properties. We have tested the accuracy of the model and analyzed the relevance of the forces arising from the electrical interaction with the AFM probe cantilever. In this way, by using this model, it is now possible to obtain quantitative information of the local dielectric material properties in a broad frequency range. Furthermore, it is also possible to determine the experimental setup providing the best sensitivity in the detected signal.

  3. Synthesis of hollow cobalt oxide nanopowders by a salt-assisted spray pyrolysis process applying nanoscale Kirkendall diffusion and their electrochemical properties.

    PubMed

    Ju, Hyeon Seok; Cho, Jung Sang; Kim, Jong Hwa; Choi, Yun Ju; Kang, Yun Chan

    2015-12-21

    A new concept for preparing hollow metal oxide nanopowders by salt-assisted spray pyrolysis applying nanoscale Kirkendall diffusion is introduced. The composite powders of metal oxide and indecomposable metal salt are prepared by spray pyrolysis. Post-treatment under a reducing atmosphere and subsequent washing using distilled water produce aggregation-free metal nanopowders. The metal nanopowders are then transformed into metal oxide hollow nanopowders by nanoscale Kirkendall diffusion. Co3O4 hollow nanopowders are prepared as first target materials. A cobalt oxide-NaCl composite powder prepared by spray pyrolysis transforms into several Co3O4 hollow nanopowders by several treatment processes. The discharge capacities of the Co3O4 nanopowders with filled and hollow structures at a current density of 1 A g(-1) for the 150th cycle are 605 and 775 mA h g(-1), respectively. The hollow structure formed by nanoscale Kirkendall diffusion improves the lithium-ion storage properties of Co3O4 nanopowders. PMID:26571144

  4. Nanoscale control of phonon excitations in graphene

    PubMed Central

    Kim, Hyo Won; Ko, Wonhee; Ku, JiYeon; Jeon, Insu; Kim, Donggyu; Kwon, Hyeokshin; Oh, Youngtek; Ryu, Seunghwa; Kuk, Young; Hwang, Sung Woo; Suh, Hwansoo

    2015-01-01

    Phonons, which are collective excitations in a lattice of atoms or molecules, play a major role in determining various physical properties of condensed matter, such as thermal and electrical conductivities. In particular, phonons in graphene interact strongly with electrons; however, unlike in usual metals, these interactions between phonons and massless Dirac fermions appear to mirror the rather complicated physics of those between light and relativistic electrons. Therefore, a fundamental understanding of the underlying physics through systematic studies of phonon interactions and excitations in graphene is crucial for realising graphene-based devices. In this study, we demonstrate that the local phonon properties of graphene can be controlled at the nanoscale by tuning the interaction strength between graphene and an underlying Pt substrate. Using scanning probe methods, we determine that the reduced interaction due to embedded Ar atoms facilitates electron–phonon excitations, further influencing phonon-assisted inelastic electron tunnelling. PMID:26109454

  5. Temperature mapping of operating nanoscale devices by scanning probe thermometry

    PubMed Central

    Menges, Fabian; Mensch, Philipp; Schmid, Heinz; Riel, Heike; Stemmer, Andreas; Gotsmann, Bernd

    2016-01-01

    Imaging temperature fields at the nanoscale is a central challenge in various areas of science and technology. Nanoscopic hotspots, such as those observed in integrated circuits or plasmonic nanostructures, can be used to modify the local properties of matter, govern physical processes, activate chemical reactions and trigger biological mechanisms in living organisms. The development of high-resolution thermometry techniques is essential for understanding local thermal non-equilibrium processes during the operation of numerous nanoscale devices. Here we present a technique to map temperature fields using a scanning thermal microscope. Our method permits the elimination of tip–sample contact-related artefacts, a major hurdle that so far has limited the use of scanning probe microscopy for nanoscale thermometry. We map local Peltier effects at the metal–semiconductor contacts to an indium arsenide nanowire and self-heating of a metal interconnect with 7 mK and sub-10 nm spatial temperature resolution. PMID:26936427

  6. Temperature mapping of operating nanoscale devices by scanning probe thermometry

    NASA Astrophysics Data System (ADS)

    Menges, Fabian; Mensch, Philipp; Schmid, Heinz; Riel, Heike; Stemmer, Andreas; Gotsmann, Bernd

    2016-03-01

    Imaging temperature fields at the nanoscale is a central challenge in various areas of science and technology. Nanoscopic hotspots, such as those observed in integrated circuits or plasmonic nanostructures, can be used to modify the local properties of matter, govern physical processes, activate chemical reactions and trigger biological mechanisms in living organisms. The development of high-resolution thermometry techniques is essential for understanding local thermal non-equilibrium processes during the operation of numerous nanoscale devices. Here we present a technique to map temperature fields using a scanning thermal microscope. Our method permits the elimination of tip-sample contact-related artefacts, a major hurdle that so far has limited the use of scanning probe microscopy for nanoscale thermometry. We map local Peltier effects at the metal-semiconductor contacts to an indium arsenide nanowire and self-heating of a metal interconnect with 7 mK and sub-10 nm spatial temperature resolution.

  7. Temperature mapping of operating nanoscale devices by scanning probe thermometry.

    PubMed

    Menges, Fabian; Mensch, Philipp; Schmid, Heinz; Riel, Heike; Stemmer, Andreas; Gotsmann, Bernd

    2016-01-01

    Imaging temperature fields at the nanoscale is a central challenge in various areas of science and technology. Nanoscopic hotspots, such as those observed in integrated circuits or plasmonic nanostructures, can be used to modify the local properties of matter, govern physical processes, activate chemical reactions and trigger biological mechanisms in living organisms. The development of high-resolution thermometry techniques is essential for understanding local thermal non-equilibrium processes during the operation of numerous nanoscale devices. Here we present a technique to map temperature fields using a scanning thermal microscope. Our method permits the elimination of tip-sample contact-related artefacts, a major hurdle that so far has limited the use of scanning probe microscopy for nanoscale thermometry. We map local Peltier effects at the metal-semiconductor contacts to an indium arsenide nanowire and self-heating of a metal interconnect with 7 mK and sub-10 nm spatial temperature resolution. PMID:26936427

  8. Physical properties of mixed dairy food proteins

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Mixed food protein gels are complex systems, which changes functional behaviors such as gelling properties and viscosity depending on the miscibility of the proteins. We have noted that differences in co-solubility of mixed proteins created unique network structures and gel properties. The effects o...

  9. Mechanical and physical properties of plasma-sprayed stabilized zirconia

    NASA Technical Reports Server (NTRS)

    Siemers, P. A.; Mehan, R. L.

    1983-01-01

    Physical and mechanical properties were determined for plasma-sprayed MgO- or Y2O3-stabilized ZrO2 thermal barrier coatings. Properties were determined for the ceramic coating in both the freestanding condition and as-bonded to a metal substrate. The properties of the NiCrAlY bond coating were also investigated.

  10. Biochemical basis of physical properties of respiratory tract secretions.

    PubMed

    Lopez-Vidriero, M T

    1987-01-01

    The physical properties of respiratory tract secretion (RTS) play a prominent rôle in the non-specific defence mechanisms of the lung. Viscosity and elasticity, that is flow and deformation, are only two of the physical properties of RTS. Spinability, pourability, adhesiveness and tackiness are starting to be recognised as physical properties of RTS and its is likely that they may be relevant in the pathogenesis of airways obstruction. RTS is a gel, which consists of a cross-linked polymer network dispersed in a liquid solvent. The polymeric structure of the epithelial glycoprotein can be explained in terms of covalent (disulphide) linkages and/or physical entanglement between glycoproteins subunits. Other constituents of RTS such as proteins, lipids, ions and water can influence the physical properties of RTS. PMID:3322857

  11. Physical and mechanical properties of icebergs

    SciTech Connect

    Gammon, P.H.; Bobby, W.; Gagnon, R.E.; Russell, W.E.

    1983-05-01

    Physical and mechanical characteristics of iceberg ice were studied from samples collected near the shores of eastern Newfoundland. Although the physical characteristics show considerable diversity, iceberg ice has some common features and is generally porous, lacks significant concentrations of dissolved materials, contains internal cracks and has an irregular interlocking grain structure. A review of mechanical testing of ice was carried out and an experimental setup was devised to reduce effects of improper contact between specimen and loading apparatus. Uniaxial compressive strength for iceberg ice was determined and compared with that for lake ice. The strength of iceberg ice was higher than that of lake ice but Young's Modulus for lake ice was higher.

  12. Structure and physical properties of transparent ferroelectric ceramics

    NASA Astrophysics Data System (ADS)

    Krumin', A. E.; Shternberg, A. R.

    1987-10-01

    Transparent ferroelectric ceramics (TFCs) are currently being used in the design of various solid-state optoelectronic devices. This paper examines the composition and structure of TFCs as well as requirements on the preparation of TFCs and criteria for the search for new TFC compositions. The properties of TFCs are examined, including the electrooptical effect, optical and electrooptical properties in the infrared, nonlinear-optical properties, the effect of radiation on the physical properties of TFCs, and phase-transition characteristics.

  13. Method of a Generalized Physical Property in the Crystal Physics Problems

    NASA Astrophysics Data System (ADS)

    Davydov, V. N.; Lugina, N. É.

    2016-06-01

    A method is proposed for determining the crystallographic directions in crystals of various point symmetry, along which the combination of physical properties of various ranks and Curie symmetry gets a predetermined value. The method is demonstrated for the combination of the second-rank tensors describing optical and thermal properties of crystals of the monoclinic system. The possibility of using the proposed method for the physical properties of high ranks is demonstrated.

  14. Fuel and physical properties of biodiesel components

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biodiesel is an alternative diesel fuel derived from vegetable oils, animal fats or used oils. Specifically, biodiesel is the methyl or other alkyl esters of these oils or fats. Biodiesel also contains minor components such as free fatty acids and acylglycerols. Important fuel properties of biodi...

  15. Nanoscale Mapping of the Magnetic Properties of (111)-Oriented La(0.67)Sr(0.33)MnO3.

    PubMed

    O'Shea, Kerry J; MacLaren, Donald A; McGrouther, Damien; Schwarzbach, Danny; Jungbauer, Markus; Hühn, Sebastian; Moshnyaga, Vasily; Stamps, Robert L

    2015-09-01

    Spatially resolved analysis of magnetic properties on the nanoscale remains challenging, yet strain and defects on this length-scale can profoundly affect a material's bulk performance. We present a detailed investigation of the magnetic properties of La0.67Sr0.33MnO3 thin films in both free-standing and nanowire form and assess the role of strain and local defects in modifying the films' magnetic properties. Lorentz transmission electron microscopy is used to measure the magnetocrystalline anisotropy and to map the Curie temperature and saturation magnetization with nanometric spatial resolution. Atomic-scale defects are identified as pinning sites for magnetic domain wall propagation. Measurement of domain wall widths and crystalline strain are used to identify a strong magnetoelastic contribution to the magnetic anisotropy. Together, these results provide unique insight into the relationship between the nanostructure and magnetic functionality of a ferromagnetic complex oxide film. PMID:26252745

  16. Highly Anti-UV Properties of Silk Fiber with Uniform and Conformal Nanoscale TiO2 Coatings via Atomic Layer Deposition.

    PubMed

    Xiao, Xingfang; Liu, Xin; Chen, Fengxiang; Fang, Dong; Zhang, Chunhua; Xia, Liangjun; Xu, Weilin

    2015-09-30

    In this study, silk fiber was successfully modified via the application of a nanoscale titania coating using atomic layer deposition (ALD), with titanium tetraisopropoxide (TIP) and water as precursors at 100 °C. Scanning electron microscopy, X-ray energy dispersive spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscope, and field emission scanning electron microscope results demonstrated that uniform and conformal titania coatings were deposited onto the silk fiber. The thermal and mechanical properties of the TiO2 silk fiber were then investigated. The results showed that the thermal stability and mechanical properties of this material were superior to those of the uncoated substance. Furthermore, the titania ALD process provided the silk fiber with excellent protection against UV radiation. Specifically, the TiO2-coated silk fibers exhibited significant increases in UV absorbance, considerably less yellowing, and greatly enhanced mechanical properties compared with the uncoated silk fiber after UV exposure. PMID:26389713

  17. DNA in Nanoscale Electronics

    NASA Astrophysics Data System (ADS)

    Slinker, Jason

    2012-10-01

    DNA, the quintessential molecule of life, possesses a number of attractive properties for use in nanoscale circuits. Charge transport (CT) through DNA itself is of both fundamental and practical interest. Fundamentally, DNA has a unique configuration of π-stacked bases in a well ordered, double helical structure. Given its unparalleled importance to life processes and its arrangement of conjugated subunits, DNA has been a compelling target of conductivity studies. In addition, further understanding of DNA CT will elucidate the biological implications of this process and advance its use in sensing technologies. We have investigated the fundamentals of DNA CT by measuring the electrochemistry of DNA monolayers under biologically-relevant conditions. We have uncovered both fundamental kinetic parameters to distinguish between competing models of operation as well as the practical implications of DNA CT for sensing. Furthermore, we are leveraging our studies of DNA conductivity for the manufacture of nanoscale circuits. We are investigating the electrical properties and self-assembly of DNA nanowires containing artificial base pair surrogates, which can be prepared through low cost and high throughput automated DNA synthesis. This unique and economically viable approach will establish a new paradigm for the scalable manufacture of nanoscale semiconductor devices.

  18. Prediction of Solvent Physical Properties using the Hierarchical Clustering Method

    EPA Science Inventory

    Recently a QSAR (Quantitative Structure Activity Relationship) method, the hierarchical clustering method, was developed to estimate acute toxicity values for large, diverse datasets. This methodology has now been applied to the estimate solvent physical properties including sur...

  19. Nanoscale Proteomics

    SciTech Connect

    Shen, Yufeng; Tolic, Nikola; Masselon, Christophe D.; Pasa-Tolic, Liljiana; Camp, David G.; Anderson, Gordon A.; Smith, Richard D.; Lipton, Mary S.

    2004-02-01

    This paper describes efforts to develop a liquid chromatography (LC)/mass spectrometry (MS) technology for ultra-sensitive proteomics studies, i.e. nanoscale proteomics. The approach combines high-efficiency nano-scale LC with advanced MS, including high sensitivity and high resolution Fourier transform ion cyclotron resonance (FTICR) MS, to perform both single-stage MS and tandem MS (MS/MS) proteomic analyses. The technology developed enables large-scale protein identification from nanogram size proteomic samples and characterization of more abundant proteins from sub-picogram size complex samples. Protein identification in such studies using MS is feasible from <75 zeptomole of a protein, and the average proteome measurement throughput is >200 proteins/h and ~3 h/sample. Higher throughput (>1000 proteins/h) and more sensitive detection limits can be obtained using a “accurate mass and time” tag approach developed at our laboratory. These capabilities lay the foundation for studies from single or limited numbers of cells.

  20. Predicting Soil Biological and Physical Properties Using Hydrological Properties

    NASA Astrophysics Data System (ADS)

    Geiger, L.; Hofmockel, K.; Kaleita, A.; Hargreaves, S.

    2012-12-01

    Soil biological and chemical properties vary at different spatial scales, which make predicting processes associated with these properties difficult. However, soil biological and chemical properties are important to fertility and ecosystem functioning. In this study, we used a Self Organizing Map (SOM) to determine whether soil hydrological characteristics can be used to characterize the distribution of a suite of soil biological and chemical properties. From a row crop field in south-central Iowa, we generated 36 sampling locations via a SOM, which were grouped into three categories according to hydrological properties by the SOM. Soil samples were then analyzed for microbial biomass, carbon and nitrogen mineralization potential, and organic and inorganic pools of carbon and nitrogen. We found that sampling locations in category 1 (potholes and toe slopes) had greater microbial biomass, total carbon, total nitrogen, and extractable organic carbon than compared locations in the two well-drained categories. Nitrogen and carbon mineralization and inorganic nitrogen pools did not differ significantly among the categories. These results demonstrate that hydrological characteristics can be used to predict relatively stable biological and chemical soil properties. However, prediction of nitrogen and carbon fluxes remains a challenge.

  1. Microwave techniques for physical property measurements

    NASA Technical Reports Server (NTRS)

    Barmatz, M.

    1993-01-01

    Industrial processing of metals and ceramics is now being streamlined by the development of theoretical models. High temperature thermophysical properties of these materials are required to successfully apply these theories. Unfortunately, there is insufficient experimental data available for many of these properties, particularly in the molten state. Microwave fields can be used to measure specific heat, thermal diffusivity, thermal conductivity and dielectric constants at high temperatures. We propose to (1) develop a microwave flash method (analogous to the laser flash technique) that can simultaneously measure the thermal diffusivity and specific heat of insulators and semiconductors at high temperatures, (2) an appropriate theory and experimental apparatus to demonstrate the measurement of the specific heat of a metal using a new microwave ac specific heat technique, and (3) experimental methods for noncontact measurement of the real and imaginary dielectric constants.

  2. Synthesis and Physical Properties of Liquid Crystals: An Interdisciplinary Experiment

    ERIC Educational Resources Information Center

    Van Hecke, Gerald R.; Karukstis, Kerry K.; Hanhan Li; Hendargo, Hansford C.; Cosand, Andrew J.; Fox, Marja M.

    2005-01-01

    A study involves multiple chemistry and physics concepts applied to a state of matter that has biological relevance. An experiment involving the synthesis and physical properties of liquid crystals illustrates the interdisciplinary nature of liquid crystal research and the practical devices derived from such research.

  3. 4.4 Physical Properties of the Most Important Radionuclides

    NASA Astrophysics Data System (ADS)

    Noßke, D.; Mattsson, S.; Johansson, L.

    This document is part of Subvolume A 'Fundamentals and Data in Radiobiology, Radiation Biophysics, Dosimetry and Medical Radiological Protection' of Volume 7 'Medical Radiological Physics' of Landolt-Börnstein - Group VIII 'Advanced Materials and Technologies'. It contains the Section '4.4 Physical Properties of the Most Important Radionuclides' of the Chapter '4 Dosimetry in Nuclear Medicine Diagnosis and Therapy'.

  4. Psychometric Properties of the Commitment to Physical Activity Scale

    ERIC Educational Resources Information Center

    DeBate, Rita DiGioacchino; Huberty, Jennifer; Pettee, Kelley

    2009-01-01

    Objective: To assess psychometric properties of the Commitment to Physical Activity Scale (CPAS). Methods: Girls in third to fifth grades (n = 932) completed the CPAS before and after a physical activity intervention. Psychometric measures included internal consistency, factor analysis, and concurrent validity. Results: Three CPAS factors emerged:…

  5. Interfacial band alignment and structural properties of nanoscale TiO{sub 2} thin films for integration with epitaxial crystallographic oriented germanium

    SciTech Connect

    Jain, N.; Zhu, Y.; Hudait, M. K.; Maurya, D.; Varghese, R.; Priya, S.

    2014-01-14

    We have investigated the structural and band alignment properties of nanoscale titanium dioxide (TiO{sub 2}) thin films deposited on epitaxial crystallographic oriented Ge layers grown on (100), (110), and (111)A GaAs substrates by molecular beam epitaxy. The TiO{sub 2} thin films deposited at low temperature by physical vapor deposition were found to be amorphous in nature, and high-resolution transmission electron microscopy confirmed a sharp heterointerface between the TiO{sub 2} thin film and the epitaxially grown Ge with no traceable interfacial layer. A comprehensive assessment on the effect of substrate orientation on the band alignment at the TiO{sub 2}/Ge heterointerface is presented by utilizing x-ray photoelectron spectroscopy and spectroscopic ellipsometry. A band-gap of 3.33 ± 0.02 eV was determined for the amorphous TiO{sub 2} thin film from the Tauc plot. Irrespective of the crystallographic orientation of the epitaxial Ge layer, a sufficient valence band-offset of greater than 2 eV was obtained at the TiO{sub 2}/Ge heterointerface while the corresponding conduction band-offsets for the aforementioned TiO{sub 2}/Ge system were found to be smaller than 1 eV. A comparative assessment on the effect of Ge substrate orientation revealed a valence band-offset relation of ΔE{sub V}(100) > ΔE{sub V}(111) > ΔE{sub V}(110) and a conduction band-offset relation of ΔE{sub C}(110) > ΔE{sub C}(111) > ΔE{sub C}(100). These band-offset parameters are of critical importance and will provide key insight for the design and performance analysis of TiO{sub 2} for potential high-κ dielectric integration and for future metal-insulator-semiconductor contact applications with next generation of Ge based metal-oxide field-effect transistors.

  6. Optical Spectroscopy at the Nanoscale

    NASA Astrophysics Data System (ADS)

    Hong, Xiaoping

    Recent advances in material science and fabrication techniques enabled development of nanoscale applications and devices with superior performances and high degree of integration. Exotic physics also emerges at nanoscale where confinement of electrons and phonons leads to drastically different behavior from those in the bulk materials. It is therefore rewarding and interesting to investigate and understand material properties at the nanoscale. Optical spectroscopy, one of the most versatile techniques for studying material properties and light-matter interactions, can provide new insights into the nanomaterials. In this thesis, I explore advanced laser spectroscopic techniques to probe a variety of different nanoscale phenomena. A powerful tool in nanoscience and engineering is scanning tunneling microscopy (STM). Its capability in atomic resolution imaging and spectroscopy unveiled the mystical quantum world of atoms and molecules. However identification of molecular species under investigation is one of the limiting functionalities of the STM. To address this need, we take advantage of the molecular `fingerprints' - vibrational spectroscopy, by combining an infrared light sources with scanning tunneling microscopy. In order to map out sharp molecular resonances, an infrared continuous wave broadly tunable optical parametric oscillator was developed with mode-hop free fine tuning capabilities. We then combine this laser with STM by shooting the beam onto the STM substrate with sub-monolayer diamondoids deposition. Thermal expansion of the substrate is detected by the ultrasensitive tunneling current when infrared frequency is tuned across the molecular vibrational range. Molecular vibrational spectroscopy could be obtained by recording the thermal expansion as a function of the excitation wavelength. Another interesting field of the nanoscience is carbon nanotube, an ideal model of one dimensional physics and applications. Due to the small light absorption with

  7. Rock physics properties of some lunar samples

    NASA Technical Reports Server (NTRS)

    Warren, N.; Trice, R.; Anderson, O. L.; Soga, N.

    1973-01-01

    Linear strains and acoustic velocity data for lunar samples under uniaxial and hydrostatic loading are presented. Elastic properties are presented for 60335,20; 15555,68; 15498,23; and 12063,97. Internal friction data are summarized for a number of artificial lunar glasses with compositions similar to lunar rocks 12009, 12012, 14305, 15021, and 15555. Zero porosity model-rock moduli are calculated for a number of lunar model-rocks, with mineralogies similar to Apollo 12, 14, and 16 rocks. Model-rock calculations indicate that rock types in the troctolitic composition range may provide reasonable modeling of the lunar upper mantle. Model calculations involving pore crack effects are compatible with a strong dependence of rock moduli on pore strain, and therefore of rock velocities on nonhydrostatic loading. The high velocity of rocks under uniaxial loading appears to be compatible with, and may aid in, interpretation of near-surface velocity profiles observed in the active seismic experiment.

  8. Advances in imaging and quantification of electrical properties at the nanoscale using Scanning Microwave Impedance Microscopy (sMIM)

    NASA Astrophysics Data System (ADS)

    Friedman, Stuart; Yang, Yongliang; Amster, Oskar

    2015-03-01

    Scanning Microwave Impedance Microscopy (sMIM) is a mode for Atomic Force Microscopy (AFM) enabling imaging of unique contrast mechanisms and measurement of local permittivity and conductivity at the 10's of nm length scale. Recent results will be presented illustrating high-resolution electrical features such as sub 15 nm Moire' patterns in Graphene, carbon nanotubes of various electrical states and ferro-electrics. In addition to imaging, the technique is suited to a variety of metrology applications where specific physical properties are determined quantitatively. We will present research activities on quantitative measurements using multiple techniques to determine dielectric constant (permittivity) and conductivity (e.g. dopant concentration) for a range of materials. Examples include bulk dielectrics, low-k dielectric thin films, capacitance standards and doped semiconductors. Funded in part by DOE SBIR DE-SC0009586.

  9. Structures and physical properties of R2TX3 compounds

    NASA Astrophysics Data System (ADS)

    Pan, Zhi-Yan; Cao, Chong-De; Bai, Xiao-Jun; Song, Rui-Bo; Zheng, Jian-Bang; Duan, Li-Bing

    2013-05-01

    Rare-earth compounds have been an attractive subject based on the unique electronic structures of the rare-earth elements. Novel ternary intermetallic compounds R2TX3 (R = rare-earth element or U, T = transition-metal element, X = Si, Ge, Ga, In) are a significant branch of this research field due to their complex and intriguing physical properties, such as magnetic order at low temperature, spin-glass behavior, Kondo effect, heavy fermion behavior, and so on. The unique physical properties of R2TX3 compounds are related to distinctive electronic structures, crystal structures, microinteraction, and external environment. Most R2TX3 compounds crystallize in AlB2-type or derived AlB2-type structures and exhibit many similar properties. This paper gives a concise review of the structures and physical properties of these compounds. Spin glass, magnetic susceptibility, resistivity, and specific heat of R2TX3 compounds are discussed.

  10. Physical Properties of Asteroid (1917) Cuyo

    NASA Astrophysics Data System (ADS)

    Rożek, A.; Lowry, S. C.; Duddy, S. R.; Snodgrass, C.; Weissman, P. R.; Wolters, S. D.; Fitzsimmons, A.; Green, S. F.; Hicks, M. D.; Rozitis, B.

    2013-09-01

    Asteroid (1917) Cuyo is a Near-Earth Asteroid (NEA) from the Amor group. It is orbitting the Sun on a highly elongated orbit with semimajor axis 2.15 AU and eccentricity 0.504. At a low delta-V (8.6 kms-1) it could be a potential target for future spacecraft missions. Radar observations indicated a slight elongation of the object with a "breadth ratio" of the asteroid's mean cross section estimated to be 1.14 [7]. Further studies showed its rotation period to be 2.6905 ± 0.0007h [11], and it was classified as 'Sr' type in the Bus-DeMeo taxonomy [8]. Cuyo was observed as part of our ESO Large Programme. The programme includes ongoing optical photometric monitoring of selected NEAs, thermal-IR observations, and optical-NIR spectroscopy. Among the principal aims of the programme are the physical characterisation of NEAs, shape modelling, and search for YORP-induced changes in rotation periods. Here we present our latest results and analysis from our observational monitoring of (1917) Cuyo. We are conducting a broad study of this asteroid, including optical photometry and spectroscopy, and thermal-IR observations. This work is ongoing and we shall present our latest results at the meeting.

  11. Effects of Nanoscale Structure on the Magnetism and Transport Properties of Chromium and Chromium-Aluminum Alloys

    NASA Astrophysics Data System (ADS)

    Boekelheide, Zoe Austin

    This thesis studies the unique properties of Cr and Cr-Al alloys; the first half focuses on Cr while the second half focuses on Cr-Al alloys. This thesis particularly focuses on the effects of nanoscale structure such as crystal defects, grain boundaries, and short- to medium-range chemical ordering, on both the magnetism and the electronic transport properties of Cr and Cr-Al. This thesis aimed to understand the spin density waves (SDW) in polycrystalline Cr films such as those commonly used in GMR multilayers, where disorder and stress are the important variables. Infrared reflectivity was used to measure the characteristic SDWpseudogap energies to distinguish the SDW state of Cr thin films grown under different deposition conditions (e-beam and sputtered at different argon pressures). The fundamental distinguishing properties of the films are stress and disorder, both strongly affected by the deposition conditions. Films with low stress and disorder are ISDW, like bulk Cr. Films with high tensile stress are CSDW, like Mn-doped Cr. Finally, films with high disorder, determined from the resistivity, have regions of both ISDW and CSDW. Importantly, all of the Cr films measured showed SDW signatures, showing that the SDW is quite robust even in highly disordered thin films. A low temperature magnetic phase diagram was created for Cr films. It was shown that Cr thin films show unusual and extremely deposition condition-dependent resistivity due to resonant scattering, such as residual resistivity ranging between 3 and 400 muO-cm, and significant resistivity minima at low temperature. Several experiments showed that these features are due to defects in the Cr lattice such as grain boundaries and vacancies. When a highly disordered, 400 muO-cm film with a significant minimum is annealed to 800°C, the resistivity is decreased by 10x and the depth of the minimum is decreased by 50x. On the other end of the spectrum, two low resistivity (< 10 muO-cm) samples grown in the

  12. Nanoscale characterization of the electrical properties of oxide electrodes at the organic semiconductor-oxide electrode interface in organic solar cells

    NASA Astrophysics Data System (ADS)

    MacDonald, Gordon Alex

    This dissertation focuses on characterizing the nanoscale and surface averaged electrical properties of transparent conducting oxide electrodes such as indium tin oxide (ITO) and transparent metal-oxide (MO) electron selective interlayers (ESLs), such as zinc oxide (ZnO), the ability of these materials to rapidly extract photogenerated charges from organic semiconductors (OSCs) used in organic photovoltaic (OPV) cells, and evaluating their impact on the power conversion efficiency (PCE) of OPV devices. In Chapter 1, we will introduce the fundamental principles, benefits, and the key innovations that have advanced this technology. In Chapter 2 of this dissertation, we demonstrate an innovative application of conductive probe atomic force microscopy (CAFM) to map the nanoscale electrical heterogeneity at the interface between ITO, and a well-studied OSC, copper phthalocyanine (CuPc).(MacDonald et al. (2012) ACS Nano, 6, p. 9623) In this work we collected arrays of current-voltage (J-V) curves, using a CAFM probe as the top contact of CuPc/ITO systems, to map the local J-V responses. By comparing J-V responses to known models for charge transport, we were able to determine if the local rate-limiting-step for charge transport is through the OSC (ohmic) or the CuPc/ITO interface (non-ohmic). Chapter 3 focus on the electrical property characterization of RF-magnetron sputtered ZnO (sp-ZnO) ESL films on ITO substrates. We have shown that the energetic alignment of ESLs and the OSC active materials plays a critical role in determining the PCE of OPV devices and UV light soaking sensitivity. We have used a combination of device testing, modeling, and impedance spectroscopy to characterize the effects that energetic alignment has on the charge carrier transport and distribution within the OPV device. In Chapter 4 we demonstrate that the local properties of sp-ZnO films varies as a function of the underlying ITO crystal face. We show that the local ITO crystal face determines

  13. The Acoustic Signature of Woodford Shale and Upscale Relationship from Nano-Scale Mechanical Properties and Mineralogy

    NASA Astrophysics Data System (ADS)

    Tran, M. H.; Abousleiman, Y. N.; Hoang, S. K.; Ortega, A. J.; Bobko, C.; Ulm, F.

    2007-12-01

    The complex composition of shale, the most encountered and problematic lithology in the Earth's crust, has puzzled many researchers attempting to find the key for understanding their micro- and macro-scale acoustic and mechanical signatures. Recent advances in nano-technology, in particular the progress of the Atomic Force Microscope (AFM) base indentation technique, have made it possible to mechanically study porous material at a nano scale (10-9 m) and consequently have allowed linking shale mechanical properties to intrinsic micro- and macro-properties such as porosity, packing density, and mineralogy. Based on more than 20,000 nano- indentation tests conducted on a number of shales with varying physical properties, a GeoGenomeTM model was developed to upscale macroscopic shale mechanical parameters from mineralogy composition, porosity, and packing density. In this work, the mechanical properties such as the elastic stiffness coefficients, Cij, and the anisotropic Biot's Pore Pressure Coefficients, αij, of the Woodford shale, were acquired using sonic log data and Ultra-Sonic Pulse Velocity (UPV) measurements conducted on preserved retrieved shale core samples from a 200-ft well drilled in the Woodford formation, in Oklahoma. Furthermore, the dependency of the Cij and αij, on applied stresses and the relationship between the dynamic moduli and the quasi-static moduli were also investigated using an array of piezoelectric crystals mounted around the samples while subjecting the samples to different applied stress states using a series of tri-axial tests. X-Ray Diffraction (XRD) and mercury injection tests were also performed on the retrieved core samples to obtain mineralogy composition and porosity of the shale at different depths. Comparison of the simulated mechanical and poromechanical properties and stiffness coefficients using the Quantitative GeoGenomeTM Mineralogy Simulator (QGGMSTM) with field and acoustic lab measurements showed excellent agreement

  14. Photometric Redshift with Bayesian Priors on Physical Properties of Galaxies

    NASA Astrophysics Data System (ADS)

    Tanaka, Masayuki

    2015-03-01

    We present a proof-of-concept analysis of photometric redshifts with Bayesian priors on physical properties of galaxies. This concept is particularly suited for upcoming/on-going large imaging surveys, in which only several broadband filters are available and it is hard to break some of the degeneracies in the multi-color space. We construct model templates of galaxies using a stellar population synthesis code and apply Bayesian priors on physical properties such as stellar mass and star formation rate. These priors are a function of redshift and they effectively evolve the templates with time in an observationally motivated way. We demonstrate that the priors help reduce the degeneracy and deliver significantly improved photometric redshifts. Furthermore, we show that a template error function, which corrects for systematic flux errors in the model templates as a function of rest-frame wavelength, delivers further improvements. One great advantage of our technique is that we simultaneously measure redshifts and physical properties of galaxies in a fully self-consistent manner, unlike the two-step measurements with different templates often performed in the literature. One may rightly worry that the physical priors bias the inferred galaxy properties, but we show that the bias is smaller than systematic uncertainties inherent in physical properties inferred from the spectral energy distribution fitting and hence is not a major issue. We will extensively test and tune the priors in the on-going Hyper Suprime-Cam survey and will make the code publicly available in the future.

  15. SAPHYR: the Swiss Atlas of PHYsical properties of Rocks

    NASA Astrophysics Data System (ADS)

    Wenning, Q. C.; Zappone, A. S.; Kissling, E.

    2015-12-01

    The Swiss Atlas of PHYsical properties of Rocks (SAPHYR) is a multi-year project, aiming to compile a comprehensive data set on physical properties of rocks exposed in Switzerland and surrounding areas. The ultimate goal of SAPHYR is to make these data accessible to an open and wide public, such as industrial, engineering, land and resource planning companies, as well as academic institutions. Since the early sixties worldwide geophysicists, petrologists, and engineers, focused their work on laboratory measurements of rocks physical properties, and their relations with microstructures, mineralogical compositions and other rock parameters, in the effort to constrain the geological interpretation of geophysical surveys. In combination with efforts to investigate deep structure of the continental crust by controlled source seismology, laboratories capable to reproduce pressure and temperature conditions to depth of 50km and more collected measurements of various parameters on a wide variety of rock types. In recent years, the increasing interest on non-traditional energy supply, (deep geothermal energy, shale gas) and CO2 storage renovated the interests in physical characterization of the deep underground. The idea to organize those laboratory data into a geographically referenced database (GIS) is supported by the Swiss Commission for Geophysics. The data refer to density and porosity, seismic, magnetic, thermal properties, permeability and electrical properties. An effort has been placed on collecting samples and measuring the physical properties of lithologies that are poorly documented in literature. The phase of laboratory measurements is still in progress. At present SAPHYR focuses towards developing a 3-D physical properties model of the Swiss subsurface, using the structure of the exposed geology, boreholes data and seismic surveys, combined with lab determined pressure and temperature derivatives. An early version of the final product is presented here.

  16. Physical Properties of Hanford Transuranic Waste Sludge

    SciTech Connect

    Berg, John C.

    2005-06-01

    Equipment that was purchased in the abbreviated year 1 of this project has been used during year 2 to study the fundamental behavior of materials that simulate the behavior of the Hanford transuranic waste sludge. Two significant results have been found, and each has been submitted for publication. Both studies found non-DLVO behavior in simulant systems. These separate but related studies were performed concurrently. It was previously shown in Rassat et al.'s report Physical and Liquid Chemical Simulant Formulations for Transuranic Wastes in Hanford Single-Shell Tanks that colloidal clays behave similarly to transuranic waste sludge (PNNL-14333, National Technical Information Service, U.S. Dept. of Commerce). Rassat et al. also discussed the pH and salt content of actual waste materials. It was shown that these materials exist at high pHs, generally above 10, and at high salt content, approximately 1.5 M from a mixture of different salts. A type of clay commonly studied, due to its uniformity, is a synthetic hectorite, Laponite. Therefore the work performed over the course of the last year was done mainly using suspensions of Laponite at high pH and involving high salt concentrations. One study was titled ''Relating Clay Rheology to Colloidal Parameters''. It has been submitted to the Journal of Colloid and INterface Science and is currently in the review process. The idea was to gain the ability to use measurable quantities to predict the flow behavior of clay systems, which should be similar to transuranic waste sludge. Leong et al. had previously shown that the yield stress of colloidal slurries of titania and alumina could be predicted, given the measurement of the accessible parameter zeta potential (Leong YK et al. J Chem Soc Faraday Trans, 19 (1993) 2473). Colloidal clays have a fundamentally different morphology and surface charge distribution than the spheroidal, uniformly charged colloids previously studied. This study was therefore performed in order to

  17. Effect of composition on physical properties of food powders

    NASA Astrophysics Data System (ADS)

    Szulc, Karolina; Lenart, Andrzej

    2016-04-01

    The paper presents an influence of raw material composition and technological process applied on selected physical properties of food powders. Powdered multi-component nutrients were subjected to the process of mixing, agglomeration, coating, and drying. Wetting liquids ie water and a 15% water lactose solution, were used in agglomeration and coating. The analyzed food powders were characterized by differentiated physical properties, including especially: particle size, bulk density, wettability, and dispersibility. The raw material composition of the studied nutrients exerted a statistically significant influence on their physical properties. Agglomeration as well as coating of food powders caused a significant increase in particle size, decreased bulk density, increased apparent density and porosity, and deterioration in flowability in comparison with non-agglomerated nutrients.

  18. Physical properties of fixed prosthodontic, resin composite luting agents.

    PubMed

    White, S N; Yu, Z

    1993-01-01

    This study determined and compared physical properties of six fixed prosthodontic resin composite luting agents and one control. Inorganic filler content, compressive strength, diametral tensile strength, film thickness, and Knoop hardness were determined. The amounts of filler and the physical properties varied widely among materials. One material, which contained a minimal amount of filler, underwent so much plastic deformation that its strengths could not be measured. All other materials demonstrated high strengths. The materials with the least filler demonstrated the least resistance to indentation. The material with the lowest film thickness had not set at the time of measurement, 10 minutes after mixing. Most materials had unacceptable film thicknesses. Only one material demonstrated acceptable physical properties throughout the study. PMID:8240650

  19. Investigating correlation between legal and physical property: possibilities and constraints

    NASA Astrophysics Data System (ADS)

    Dimopoulou, E.; Kitsakis, D.; Tsiliakou, E.

    2015-06-01

    Contemporary urban environment is characterized by complexity and mixed use of space, in which overlapping land parcels and different RRRs (Rights, Restrictions and Responsibilities) are frequent phenomena. Internationally, real property legislation either focuses on surface property or has introduced individual 3D real property units. The former approach merely accommodates issues related to subdivision, expropriation and transactions on part of the real property above or below surface, while the latter provides for defining and registering 3D real property units. National laws require two-dimensional real property descriptions and only a limited number of jurisdictions provide for threedimensional data presentation and recording. International awareness on 3D Cadastre may be apparent through the proposals for transition of existing cadastral systems to 3D along with legal amendments improving national 3D Cadastre legislation. Concurrently the use of appropriate data sources and the correct depiction of 3D property units' boundaries and spatial relationships need to be addressed. Spatial relations and constraints amongst real world objects could be modeled geometrically and topologically utilizing numerous modeling tools, e.g. CityGML, BIM and further sophisticated 3D software or by adapting international standards, e.g. LADM. A direct correlation between legal and physical property should be based on consistent geometry between physical and legal space, improving the accuracy that legal spaces' volumes or locations are defined. To address these issues, this paper investigates correlation possibilities and constraints between legal and physical space of typical 3D property cases. These cases comprise buildings or their interior spaces with mixed use, as well as complex structures described by explicit facade patterns, generated by procedural or by BIM ready 3D models. The 3D models presented are evaluated, regarding compliancy to physical or legal reality.

  20. Physical properties of Aten, Apollo and Amor asteroids

    NASA Technical Reports Server (NTRS)

    Mcfadden, Lucy-Ann; Tholen, David J.; Veeder, Glenn J.

    1989-01-01

    Data available on the physical properties of a group of planet-crossing asteroids, the Aten, Apollo, and Amor objects (AAAO) (include data on the taxonomy, mineralogical surface composition, diameter, rotation rate, shape, and surface texture) are presented together with the type of observations used for obtaining these data. These data show that the population of the AAAO is diverse in all of their physical characteristics. This diversity implies that the AAAO come from multiple sources and had different evolutionary histories.

  1. Physical properties about metal matrix FGM of molybdenum and copper

    SciTech Connect

    Nakano, Kouichi; Nishida, Shinichi

    1995-11-01

    Metal matrix composites (MMC) have been made trials to produce by a lot of fabrication processes such as the powder metallurgical method, the plasma spraying, the diffusion bonding, the physical vapor deposition method, the hot isostatic pressing (HIP) etc. In the most cases of these processes, dissimilar materials are combined or bonded directly. The various physical properties are discontinuous at the bonded interface of the dissimilar materials. In order to overcome the problem, functionally gradient materials (FGM) have been considered recently, and have attracted the authors. Its compositions are prepared so that physical properties continuously vary across the bond interface of the dissimilar metals. In this study, a FGM is produced by a new process based on HIP. Copper and molybdenum, which are distinct in the thermo-physical property to each other, are the constitutents for the FGM. This composition have been confirmed by absorbed electron and characteristics X-ray images of each mixed layer for FGM to be uniform or continuous. The following items have been investigated and compared with the linear law of mixture rule: Vickers hardness, thermal expansion, and thermal conductivity at a one-dimensional non-steady state. Those physical properties have been identified to depend on the mixing ratios of copper and molybdenum. Pretty good agreements have been obtained between the experimental data and the calculated values according to the linear law of mixture rule.

  2. Optical/Electronic Heterogeneity of WSe2 at the Nanoscale

    NASA Astrophysics Data System (ADS)

    Park, Kyoung-Duck; Khatib, Omar; Kravtsov, Vasily; Ulbricht, Ronald; Clark, Genevieve; Xu, Xiaodong; Raschke, Markus

    Many classes of two-dimensional (2D) materials have emerged as a potential platform for novel electronic and optical devices. However, the physical properties are strongly influenced by nanoscale heterogeneities in the form of nucleation sites, defects, strains, and edges. Here we demonstrate nano-optical imaging of the associated influence on structure and electronic properties with sub-20 nm spatial resolution from combined tip-enhanced Raman scattering (TERS) and photoluminescence (TEPL) spectroscopy and imaging. In monolayer WSe2 micro-crystals grown by physical vapor deposition (PVD), we observe significant variations in TERS and TEPL near crystal edges and atomic-scale grain boundaries (GBs), consistent with variations in strain and/or exciton diffusion. Specifically, theoretical exciton diffusion lengths (25 nm) at GBs and heterogeneous nanoscale (30-80 nm) PL emission including a spectral blue-shift at edges are experimentally probed. Further, we are able to engineer the local bandgap of WSe2 crystals by dynamic AFM-control in reversible (24 meV) and irreversible (48 meV) fashions, enabling systematic in-situ studies of the coupling of mechanical degrees of freedom to the nanoscale electronic properties in layered 2D materials.

  3. Electrical Insulation Paper and Its Physical Properties at Cryogenic Temperatures

    SciTech Connect

    Tuncer, Enis; Polyzos, Georgios; Sauers, Isidor; James, David Randy

    2011-01-01

    Paper is widely used in various engineering applications due to its physical properties and ease of manufacture. As a result paper has been selected or designed as an electrical insulation material for parts and components in high voltage technology. In the current study we select a paper employed in conventional transformers as the electrical insulation material. The potential of this paper is investigated at cryogenic temperatures to determine its physical properties for high temperature superconducting power applications. Dielectric measurements were performed using impedance spectroscopy at a constant frequency. Dielectric breakdown tests were performed on samples at 77 K using a liquid nitrogen bath.

  4. Use of ultrasound to monitor physical properties of soybean oil

    NASA Astrophysics Data System (ADS)

    Baêsso, R. M.; Oliveira, P. A.; Morais, G. C.; Alvarenga, A. V.; Costa-Félix, R. P. B.

    2016-07-01

    The study of the monitoring physical properties of soybean oil was performed. The pulse-echo method allowed measuring the density and viscosity of the oil in real time and accurately. The physical property values were related to the acoustic time of flight ratio, dimensionless parameter that can be obtained from any reference. In our case, we used the time of flight at 20°C as reference and a fixed distance between the transducer and the reflector. Ultrasonic monitoring technique employed here has shown promising in the analysis of edible oils.

  5. A system for recording physical properties of clouds

    NASA Technical Reports Server (NTRS)

    Purgold, G. C.; Whitlock, C. H.

    1990-01-01

    Characterization of the physical properties of clouds is an important objective of the FIRE Project intensive field operations (IFO) planned for 1990 thru 1992. Physical properties observed from satellites will be directly compared to ground based observations during this period. The technical information is provided which is required to record local cloud parameters such as type of clouds, direction of travel, layering, and cloud fraction data. Such information should be very useful in analyzing other cloud and meteorological data. A system of the type described was deployed as part of the First Global Surface Radiation Budget Experiment in April 1989.

  6. Aerosol physical properties in the stratosphere (APPS) radiometer design

    NASA Technical Reports Server (NTRS)

    Gray, C. R.; Woodin, E. A.; Anderson, T. J.; Magee, R. J.; Karthas, G. W.

    1977-01-01

    The measurement concepts and radiometer design developed to obtain earth-limb spectral radiance measurements for the Aerosol Physical Properties in the Stratosphere (APPS) measurement program are presented. The measurements made by a radiometer of this design can be inverted to yield vertical profiles of Rayleigh scatterers, ozone, nitrogen dioxide, aerosol extinction, and aerosol physical properties, including a Junge size-distribution parameter, and a real and imaginary index of refraction. The radiometer design provides the capacity for remote sensing of stratospheric constituents from space on platforms such as the space shuttle and satellites, and therefore provides for global measurements on a daily basis.

  7. Spatial variability of snow physical properties across northwestern Greenland

    NASA Astrophysics Data System (ADS)

    Courville, Z.; Polashenski, C.; Dibb, J. E.; Domine, F.

    2013-12-01

    In the late spring and early summer of 2013, researchers on the SAGE (Sunlight Absorption on the Greenland ice sheet Experiment) Traverse, embarked on a 4000 km ground traverse across northwestern Greenland in an attempt to quantify spatial variability of snow chemistry, snow physical properties, and snow reflectance. The field team targeted sites first visited by Carl Benson during his series of traverses from 1952 to 1955 as part of his pioneering work to characterize the Greenland Ice Sheet. This route now represents a rapidly changing and variable area of Greenland, as the route passes through several of the ice sheet facies first delimited by Benson. Along the traverse, the SAGE field team made ground-based albedo measurements using a hand-held spectroradiometer and collected snow physical property samples to determine snow specific surface area (SSA) from shallow, 2m pits. In addition, snow density and stratigraphy were measured. Snow layers in the near-surface and at the previous season's melt layer were targeted for sampling. Here we present preliminary snow physical property results from the upper portion of the snow pits and relate these to surface albedo data collected over the route. Further measurements of snow properties in the 2012 melt layer will be analyzed to assess the potential role of snow chemical (see Dibb et al. for a discussion of chemical analysis) and physical property driven albedo feedbacks could have played in contributing to that event. Route of 2013 SAGE Traverse in northwestern Greenland.

  8. Nanoscale TiO₂-coated LPGs as radiation-tolerant humidity sensors for high-energy physics applications.

    PubMed

    Consales, Marco; Berruti, Gaia; Borriello, Anna; Giordano, Michele; Buontempo, Salvatore; Breglio, Giovanni; Makovec, Alajos; Petagna, Paolo; Cusano, Andrea

    2014-07-15

    This Letter deals with a feasibility analysis for the development of radiation-tolerant fiber-optic humidity sensors based on long-period grating (LPG) technology to be applied in high-energy physics (HEP) experiments currently running at the European Organization for Nuclear Research (CERN). In particular, here we propose a high-sensitivity LPG sensor coated with a finely tuned titanium dioxide (TiO₂) thin layer (~100 nm thick) through the solgel deposition method. Relative humidity (RH) monitoring in the range 0%-75% and at four different temperatures (in the range -10°C-25°C) was carried out to assess sensor performance in real operative conditions required in typical experiments running at CERN. Experimental results demonstrate the very high RH sensitivities of the proposed device (up to 1.4 nm/% RH in correspondence to very low humidity levels), which turned out to be from one to three orders of magnitude higher than those exhibited by fiber Bragg grating sensors coated with micrometer-thin polyimide overlays. The radiation tolerance capability of the TiO₂-coated LPG sensor is also investigated by comparing the sensing performance before and after its exposure to a 1 Mrad dose of γ-ionizing radiation. Overall, the results collected demonstrate the strong potential of the proposed technology with regard to its future exploitation in HEP applications as a robust and valid alternative to the commercial (polymer-based) hygrometers currently used. PMID:25121668

  9. Hydrate morphology: Physical properties of sands with patchy hydrate saturation

    USGS Publications Warehouse

    Dai, S.; Santamarina, J.C.; Waite, William F.; Kneafsey, T.J.

    2012-01-01

    The physical properties of gas hydrate-bearing sediments depend on the volume fraction and spatial distribution of the hydrate phase. The host sediment grain size and the state of effective stress determine the hydrate morphology in sediments; this information can be used to significantly constrain estimates of the physical properties of hydrate-bearing sediments, including the coarse-grained sands subjected to high effective stress that are of interest as potential energy resources. Reported data and physical analyses suggest hydrate-bearing sands contain a heterogeneous, patchy hydrate distribution, whereby zones with 100% pore-space hydrate saturation are embedded in hydrate-free sand. Accounting for patchy rather than homogeneous hydrate distribution yields more tightly constrained estimates of physical properties in hydrate-bearing sands and captures observed physical-property dependencies on hydrate saturation. For example, numerical modeling results of sands with patchy saturation agree with experimental observation, showing a transition in stiffness starting near the series bound at low hydrate saturations but moving toward the parallel bound at high hydrate saturations. The hydrate-patch size itself impacts the physical properties of hydrate-bearing sediments; for example, at constant hydrate saturation, we find that conductivity (electrical, hydraulic and thermal) increases as the number of hydrate-saturated patches increases. This increase reflects the larger number of conductive flow paths that exist in specimens with many small hydrate-saturated patches in comparison to specimens in which a few large hydrate saturated patches can block flow over a significant cross-section of the specimen.

  10. Structure and physical properties of biomembranes and model membranes

    NASA Astrophysics Data System (ADS)

    Hianik, T.

    2006-12-01

    Biomembranes belong to the most important structures of the cell and the cell organels. They play not only structural role of the barrier separating the external and internal part of the membrane but contain also various functional molecules, like receptors, ionic channels, carriers and enzymes. The cell membrane also preserves non-equillibrium state in a cell which is crucial for maintaining its excitability and other signaling functions. The growing interest to the biomembranes is also due to their unique physical properties. From physical point of view the biomembranes, that are composed of lipid bilayer into which are incorporated integral proteins and on their surface are anchored peripheral proteins and polysaccharides, represent liquid scrystal of smectic type. The biomembranes are characterized by anisotropy of structural and physical properties. The complex structure of biomembranes makes the study of their physical properties rather difficult. Therefore several model systems that mimic the structure of biomembranes were developed. Among them the lipid monolayers at an air-water interphase, bilayer lipid membranes (BLM), supported bilayer lipid membranes (sBLM) and liposomes are most known. This work is focused on the introduction into the "physical word" of the biomembranes and their models. After introduction to the membrane structure and the history of its establishment, the physical properties of the biomembranes and their models areare stepwise presented. The most focus is on the properties of lipid monolayers, BLM, sBLM and liposomes that were most detailed studied. This contribution has tutorial character that may be usefull for undergraduate and graduate students in the area of biophysics, biochemistry, molecular biology and bioengineering, however it contains also original work of the author and his co-worker and PhD students, that may be usefull also for specialists working in the field of biomembranes and model membranes.

  11. Role of organic modifiers on the enhancement of nanochemical properties of clay-based nanocomposites: A nanoscale experimental and multiscale modeling study

    NASA Astrophysics Data System (ADS)

    Sikdar, Debashis

    predict the macroscale behavior of PCNs, mesoscale modeling of PCN is conducted using MD and finite element modeling (FEM). The nanoscale properties of polymer, clay, intercalated polymer, and organic modifier have been evaluated using MD. Those nanoscale properties have been incorporated in the macroscale model of PCNs. The multiscale FEM simulations incorporate the "altered phase" model and provide quantitative information about properties of the altered polymer.

  12. Thermoelectric effects in nanoscale junctions.

    PubMed

    Dubi, Yonatan; Di Ventra, Massimiliano

    2009-01-01

    Despite its intrinsic nonequilibrium origin, thermoelectricity in nanoscale systems is usually described within a static scattering approach which disregards the dynamical interaction with the thermal baths that maintain energy flow. Using the theory of open quantum systems, we show instead that unexpected properties, such as a resonant structure and large sign sensitivity, emerge if the nonequilibrium nature of this problem is considered. Our approach also allows us to define and study a local temperature, which shows hot spots and oscillations along the system according to the coupling of the latter to the electrodes. This demonstrates that Fourier's lawa paradigm of statistical mechanicsis generally violated in nanoscale junctions. PMID:19072125

  13. LDRD-LW Final Report: 07-LW-041 "Magnetism in Semiconductor Nanocrystals: New Physics at the Nanoscale"

    SciTech Connect

    Meulenberg, R W; Lee, J I; McCall, S K

    2009-10-19

    The work conducted in this project was conducted with the aim of identifying and understanding the origin and mechanisms of magnetic behavior in undoped semiconductor nanocrystals (NCs), specifically those composed of CdSe. It was anticipated that the successful completion of this task would have the effect of addressing and resolving significant controversy over this topic in the literature. Meanwhile, application of the resultant knowledge was expected to permit manipulation of the magnetic properties, particularly the strength of any magnetic effects, which is of potential relevance in a range of advanced technologies. More specifically, the project was designed and research conducted with the goal of addressing the following series of questions: (1) How does the magnitude of the magnetism in CdSe NCs change with the organic molecules used to passivate their surface the NC size? i.e. Is the magnetism an intrinsic effect in the nanocrystalline CdSe (as observed for Au NCs) or a surface termination driven effect? (2) What is the chemical (elemental) nature of the magnetism? i.e. Are the magnetic effects associated with the Cd atoms or the Se atoms or both? (3) What is/are the underlying mechanism(s)? (4) How can the magnetism be controlled for further applications? To achieve this goal, several experimental/technical milestones were identified to be fulfilled during the course of the research: (A) The preparation of well characterized CdSe NCs with varying surface termination (B) Establishing the extent of the magnetism of these NCs using magnetometry (particularly using superconducting interference device [SQUID]) (C) Establishing the chemical nature of the magnetism using x-ray magnetic circular dichroism (XMCD) - the element specific nature of the technique allows identification of the element responsible for the magnetism (D) Identification of the effect of surface termination on the empty densities of states (DOS) using x-ray absorption spectroscopy (XAS

  14. Synthesis and physical properties of pennycress estolides and esters

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A new series of pennycress (Thlasphi arvense L.) based free-acid estolides was synthesized by an acid-catalyzed condensation reaction, followed by an esterification reaction to produce the 2-ethylhexyl (2-EH) esters of the initial estolides. The physical properties of the estolides are highly affect...

  15. Characterization of physical and aerodynamic properties of walnuts

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objective of this research was to study the physical and aerodynamic properties of freshly harvested walnuts. Measurements were carried out for three walnut varieties, Tulare, Howard and Chandler cultivated in California, USA. The nuts treated with and without Ethephon were collected from mechan...

  16. Spray characteristics affected by physical properties of adjuvants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Four drift adjuvants, Array, In-Place, Vector and Control, were tested and physical properties and spray spectrum parameters measured. Array had the highest conductivity, indicating a good potential for the electrostatic charging, and the highest shear viscosity. All adjuvants had very similar neut...

  17. IMPROVED PHYSICAL PROPERTIES OF ZEIN USING GLYOXAL AS A CROSSLINKER

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The effect of crosslinkers glyoxal, methylglyoxal and formaldehyde on physical properties of zein films was studied. Zein was solubilized in 90%(v/v) aqueous ethanol and the pH was adjusted with either hydrochloric acid or sodium hydroxide. Crosslinkers were added to 0.3, 1, 3 and 6%(w/w by zein w...

  18. Tillage effects on soil physical properties, sugarbeet yield and quality

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Tillage influences the soil-water-plant ecosystem thereby affecting crop yield and quality. The effects of tillage on soil physical properties, sugarbeet (Beta vulgaris L.) yield and quality were evaluated. A field study comprises of three tillage practices: no tillage (NT) shallow (ST) of 10-cm and...

  19. Physical property characterization of 183-H Basin sludge

    SciTech Connect

    Biyani, R.K.; Delegard, C.H.

    1995-09-20

    This document describes the characterization of 183-H Basin sludge physical properties, e.g. bulk density of sludge and absorbent, and determination of free liquids. Calcination of crucible-size samples of sludge was also done and the resulting `loss-on-ignition` was compared to the theoretical weight loss based on sludge analysis obtained from Weston Labs.

  20. Effect of adjuvant physical properties on spray characteristics

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The effects of adjuvant physical properties on spray characteristics were studied. Dynamic surface tension was measured with a Sensa Dyne surface tensiometer 6000 using the maximum bubble pressure method. Viscosity was measured with a Brookfield synchro-lectric viscometer model LVT using a UL adap...

  1. Physical and Chemical Properties of Anthropogenic Aerosols: An overview

    EPA Science Inventory

    A wide variety of anthropogenic sources emit fine aerosols to the atmosphere. The physical and chemical properties of these aerosols are of interest due to their influence on climate, human health, and visibility. Aerosol chemical composition is complex. Combustion aerosols can c...

  2. Physical Properties of Meteorite Falls in Relation to Planetary Defense

    NASA Astrophysics Data System (ADS)

    Ostrowski, D.; Sears, D. W. G.; Bryson, K.; Agrawal, P.

    2015-07-01

    NASA ARC has set up a new lab to study a suite of physical properties of all types of meteorite falls. This is aide to the Planetary Defense initiative at Ames in determining how to deflect or the impact outcome of potentially hazardous bodies.

  3. Mechanical and physical properties of modern boron fibers

    NASA Technical Reports Server (NTRS)

    Dicarlo, J. A.

    1978-01-01

    The results of accurate measurements of the modern boron fiber's Young's modulus, flexural modulus, shear modulus, and Poisson's ratio are reported. Physical property data concerning fiber density, thermal expansion, and resistance obtained during the course of the mechanical studies are also given.

  4. IMPROVED PHYSICAL PROPERTIES OF ZEIN USING GLYOXAL AS A CROSSLINKER

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The effect of crosslinkers glyoxal, methylglyoxal and formaldehyde on physical properties of zein films was studied. Crosslinker concentrations varied from 0.3 to 6% by zein weight. Films crosslinked with glyoxal and formaldehyde showed a significant increase in tensile strength under certain pH c...

  5. Spectral Reflectance Estimates of Surface Soil Physical and Chemical Properties

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Optical diffuse reflectance sensing in visible and near-infrared wavelength ranges is one approach to rapidly quantify soil properties for site-specific management. The objectives of this study were (1) to determine the accuracy of the reflectance approach for estimating physical and chemical proper...

  6. Nanoscale Optoelectronic Photosynthetic Devices

    NASA Astrophysics Data System (ADS)

    Greenbaum, Elias; Lee, Ida; Guillorn, Michael; Lee, James W.; Simpson, Michael L.

    2001-03-01

    This presentation provides an overview and recent progress in the Oak Ridge National Laboratory research program in molecular electronics and green plant photosynthesis. The photosynthetic reaction center is a nanoscale molecular diode and photovoltaic device. The key thrust of our research program is the construction of molecular electronic devices from these nanoscale structures. Progress in this multidisciplinary research program has been demonstrated by direct electrical contact of emergent electrons with the Photosystem I (PS I) reaction center by nanoparticle precipitation. Demonstration of stable diode properties of isolated reaction centers combined with the ability to orient PS I by self-assembly on a planar surface, makes this structure a good building block for 2-D and potentially 3-D devices. Metallization of isolated PS I does not alter their fundamental photophysical properties and they can be bonded to metal surfaces. We report here the first measurement of photovoltage from single PS I reaction centers. Working at the Cornell University National Nanofabrication Facility, we have constructed sets of dissimilar metal electrodes separated by distances as small as 6 nm. We plan to use these structures to make electrical contact to both ends of oriented PSI reaction centers and thereby realize biomolecular logic circuits. Potential applications of PSI reaction centers for optoelectronic applications as well as molecular logic device construction will be discussed.

  7. Physical properties of biological entities: an introduction to the ontology of physics for biology.

    PubMed

    Cook, Daniel L; Bookstein, Fred L; Gennari, John H

    2011-01-01

    As biomedical investigators strive to integrate data and analyses across spatiotemporal scales and biomedical domains, they have recognized the benefits of formalizing languages and terminologies via computational ontologies. Although ontologies for biological entities-molecules, cells, organs-are well-established, there are no principled ontologies of physical properties-energies, volumes, flow rates-of those entities. In this paper, we introduce the Ontology of Physics for Biology (OPB), a reference ontology of classical physics designed for annotating biophysical content of growing repositories of biomedical datasets and analytical models. The OPB's semantic framework, traceable to James Clerk Maxwell, encompasses modern theories of system dynamics and thermodynamics, and is implemented as a computational ontology that references available upper ontologies. In this paper we focus on the OPB classes that are designed for annotating physical properties encoded in biomedical datasets and computational models, and we discuss how the OPB framework will facilitate biomedical knowledge integration. PMID:22216106

  8. Synthesis, characterization, and physical properties of 1D nanostructures

    NASA Astrophysics Data System (ADS)

    Marley, Peter Mchael

    framework is facilitated by the nanometer-sized dimensions of the materials, which leads to accommodation of strain without amorphization. The topotactic approach demonstrated here indicates not just novel intercalation chemistry accessible at nanoscale dimensions but also suggests a facile synthetic route to ternary vanadium oxide bronzes (MxV2O 5) exhibiting intriguing physical properties that range from electronic phase transitions to charge ordering and superconductivity.

  9. Physical Properties of Five Brands of K-Files

    PubMed Central

    Izadi, Arash; Shahravan, Arash; Shabani Nejad, Hoda

    2016-01-01

    Introduction: Endodontic K-files are major tools for cleaning and shaping of the root canal systems. As there are various K-files available in Iranian market, the physical properties of the five available brands were investigated to assist the clinician when selecting suitable endodontic K-files according to the intended application. Materials and Methods: Physical properties (including debris creation, machinery defect and corrosion) of the selected K-files were investigated by a scanning electron microscope (SEM) under ×250 magnification. For evaluating the flutes number, a stereomicroscope was used with ×40 magnification. Results: Maximum and minimum debris and corrosion were observed in the Larmrose and Perfect K-files, respectively. Dentsply showed the least machinery defects. Other brands had intermediary properties. In addition, Larmrose K-files showed the maximum flutes number compared to the other brands. Conclusion: According to the results, none of the K-files had the ideal properties. More studies regarding the physical properties of the K-files and their clinical efficacy are suggested. PMID:27141219

  10. Process depending morphology and resulting physical properties of TPU

    SciTech Connect

    Frick, Achim Spadaro, Marcel

    2015-12-17

    Thermoplastic polyurethane (TPU) is a rubber like material with outstanding properties, e.g. for seal applications. TPU basically provides high strength, low frictional behavior and excellent wear resistance. Though, due to segmented structure of TPU, which is composed of hard segments (HSs) and soft segments (SSs), physical properties depend strongly on the morphological arrangement of the phase separated HSs at a certain ratio of HSs to SSs. It is obvious that the TPU deforms differently depending on its bulk morphology. Basically, the morphology can either consist of HSs segregated into small domains, which are well dispersed in the SS matrix or of few strongly phase separated large size HS domains embedded in the SS matrix. The morphology development is hardly ruled by the melt processing conditions of the TPU. Depending on the morphology, TPU provides quite different physical properties with respect to strength, deformation behavior, thermal stability, creep resistance and tribological performance. The paper deals with the influence of important melt processing parameters, such as temperature, pressure and shear conditions, on the resulting physical properties tested by tensile and relaxation experiments. Furthermore the morphology is studied employing differential scanning calorimeter (DSC), transmission light microscopy (TLM), scanning electron beam microscopy (SEM) and transmission electron beam microscopy (TEM) investigations. Correlations between processing conditions and resulting TPU material properties are elaborated. Flow and shear simulations contribute to the understanding of thermal and flow induced morphology development.

  11. Physical and mechanical properties of the lunar soil (a review)

    NASA Astrophysics Data System (ADS)

    Slyuta, E. N.

    2014-09-01

    We review the data on the physical and mechanical properties of the lunar soil that were acquired in the direct investigations on the lunar surface carried out in the manned and automatic missions and in the laboratory examination of the lunar samples returned to the Earth. In justice to the American manned program Apollo, we show that a large volume of the data on the properties of the lunar soil was also obtained in the Soviet automatic program Lunokhod and with the automatic space stations Luna-16, -20, and -24 that returned the lunar soil samples to the Earth. We consider all of the main physical and mechanical properties of the lunar soil, such as the granulometric composition, density and porosity, cohesion and adhesion, angle of internal friction, shear strength of loose soil, deformation characteristics (the deformation modulus and Poisson ratio), compressibility, and the bearing capacity, and show the change of some properties versus the depth. In most cases, the analytical dependence of the main parameters is presented, which is required in developing reliable engineering models of the lunar soil. The main physical and mechanical properties are listed in the summarizing table, and the currently available models and simulants of the lunar soil are reviewed.

  12. Process depending morphology and resulting physical properties of TPU

    NASA Astrophysics Data System (ADS)

    Frick, Achim; Spadaro, Marcel

    2015-12-01

    Thermoplastic polyurethane (TPU) is a rubber like material with outstanding properties, e.g. for seal applications. TPU basically provides high strength, low frictional behavior and excellent wear resistance. Though, due to segmented structure of TPU, which is composed of hard segments (HSs) and soft segments (SSs), physical properties depend strongly on the morphological arrangement of the phase separated HSs at a certain ratio of HSs to SSs. It is obvious that the TPU deforms differently depending on its bulk morphology. Basically, the morphology can either consist of HSs segregated into small domains, which are well dispersed in the SS matrix or of few strongly phase separated large size HS domains embedded in the SS matrix. The morphology development is hardly ruled by the melt processing conditions of the TPU. Depending on the morphology, TPU provides quite different physical properties with respect to strength, deformation behavior, thermal stability, creep resistance and tribological performance. The paper deals with the influence of important melt processing parameters, such as temperature, pressure and shear conditions, on the resulting physical properties tested by tensile and relaxation experiments. Furthermore the morphology is studied employing differential scanning calorimeter (DSC), transmission light microscopy (TLM), scanning electron beam microscopy (SEM) and transmission electron beam microscopy (TEM) investigations. Correlations between processing conditions and resulting TPU material properties are elaborated. Flow and shear simulations contribute to the understanding of thermal and flow induced morphology development.

  13. Biomedically relevant chemical and physical properties of coal combustion products.

    PubMed Central

    Fisher, G L

    1983-01-01

    The evaluation of the potential public and occupational health hazards of developing and existing combustion processes requires a detailed understanding of the physical and chemical properties of effluents available for human and environmental exposures. These processes produce complex mixtures of gases and aerosols which may interact synergistically or antagonistically with biological systems. Because of the physicochemical complexity of the effluents, the biomedically relevant properties of these materials must be carefully assessed. Subsequent to release from combustion sources, environmental interactions further complicate assessment of the toxicity of combustion products. This report provides an overview of the biomedically relevant physical and chemical properties of coal fly ash. Coal fly ash is presented as a model complex mixture for health and safety evaluation of combustion processes. PMID:6337824

  14. The Influence of Fuelbed Physical Properties on Biomass Burning Emissions

    NASA Astrophysics Data System (ADS)

    Urbanski, S. P.; Lincoln, E.; Baker, S. P.; Richardson, M.

    2014-12-01

    Emissions from biomass fires can significantly degrade regional air quality and therefore are of major concern to air regulators and land managers in the U.S. and Canada. Accurately estimating emissions from different fire types in various ecosystems is crucial to predicting and mitigating the impact of fires on air quality. The physical properties of ecosystems' fuelbeds can heavily influence the combustion processes (e.g. flaming or smoldering) and the resultant emissions. However, despite recent progress in characterizing the composition of biomass smoke, significant knowledge gaps remain regarding the linkage between basic fuelbed physical properties and emissions. In laboratory experiments we examined the effects of fuelbed properties on combustion efficiency (CE) and emissions for an important fuel component of temperate and boreal forests - conifer needles. The bulk density (BD), depth (DZ), and moisture content (MC) of Ponderosa Pine needle fuelbeds were manipulated in 75 burns for which gas and particle emissions were measured. We found CE was negatively correlated with BD, DZ and MC and that the emission factors of species associated with smoldering combustion processes (CO, CH4, particles) were positively correlated with these fuelbed properties. The study indicates the physical properties of conifer needle fuelbeds have a significant effect on CE and hence emissions. However, many of the emission models used to predict and manage smoke impacts on air quality assume conifer litter burns by flaming combustion with a high CE and correspondingly low emissions of CO, CH4, particles, and organic compounds. Our results suggest emission models underestimate emissions from fires involving a large component of conifer needles. Additionally, our findings indicate that laboratory studies of emissions should carefully control fuelbed physical properties to avoid confounding effects that may obscure the effects being tested and lead to erroneous interpretations.

  15. Nanoscale Control Over Interfacial Properties in Mixed Reverse Micelles Formulated by Using Sodium 1,4-bis-2-ethylhexylsulfosuccinate and Tri-n-octyl Phosphine Oxide Surfactants.

    PubMed

    Odella, Emmanuel; Falcone, R Darío; Silber, Juana J; Correa, N Mariano

    2016-08-01

    The interfacial properties of pure reverse micelles (RMs) are a consequence of the magnitude and nature of noncovalent interactions between confined water and the surfactant polar head. Addition of a second surfactant to form mixed RMs is expected to influence these interactions and thus affect these properties at the nanoscale level. Herein, pure and mixed RMs stabilized by sodium 1,4-bis-2-ethylhexylsulfosuccinate and tri-n-octyl phosphine oxide (TOPO) surfactants in n-heptane were formulated and studied by varying both the water content and the TOPO mole fraction. The microenvironment generated was sensed by following the solvatochromic behavior of the 1-methyl-8-oxyquinolinium betaine probe and (31) P NMR spectroscopy. The results reveal unique properties of mixed RMs and we give experimental evidence that free water can be detected in the polar core of the mixed RMs at very low water content. We anticipate that these findings will have an impact on the use of such media as nanoreactors for many types of chemical reactions, such as enzymatic reactions and nanoparticle synthesis. PMID:27128745

  16. Gamma Radiation Effects on Physical, Optical, and Structural Properties of Binary As-S glasses

    SciTech Connect

    Sundaram, S. K.; McCloy, John S.; Riley, Brian J.; Murphy, Mark K.; Qiao, Hong; Windisch, Charles F.; Walter, Eric D.; Crum, Jarrod V.; Golovchak, Roman; Shpotyuk, O.

    2012-03-01

    Gamma radiation induces changes in physical, optical, and structural properties in chalcogenide glasses., Previous research has focused on As{sub 2}S{sub 3} and families of glasses containing Ge. For the first time, we present composition and dose dependent data on the As-S binary glass series. Binary As{sub x}S{sub 100-x} (x = 30, 33, 36, 40, and 42) glasses were irradiated with gamma radiation using a {sup 60}Co source at 2.8 Gy/s to accumulated doses of 1, 2, 3, and 4 MGy. The irradiated samples were characterized at each dose level for density, refractive index, x-ray diffraction, and Raman spectrum. These results are compared to those of as-made and 1 year aged samples. We report an initial increase in density followed by a decrease as a function of dose that contradicts the expected compositional dependence of molar volume of these glasses. This unusual behavior is explained based on microvoid formation and nanoscale phase-separation induced by the irradiation in these glasses. XRD, Raman, and EPR data provide supporting evidence, underscoring the importance of optimally- or overly-constrained structures for stability under aging or irradiation.

  17. Influence of wheat kernel physical properties on the pulverizing process.

    PubMed

    Dziki, Dariusz; Cacak-Pietrzak, Grażyna; Miś, Antoni; Jończyk, Krzysztof; Gawlik-Dziki, Urszula

    2014-10-01

    The physical properties of wheat kernel were determined and related to pulverizing performance by correlation analysis. Nineteen samples of wheat cultivars about similar level of protein content (11.2-12.8 % w.b.) and obtained from organic farming system were used for analysis. The kernel (moisture content 10 % w.b.) was pulverized by using the laboratory hammer mill equipped with round holes 1.0 mm screen. The specific grinding energy ranged from 120 kJkg(-1) to 159 kJkg(-1). On the basis of data obtained many of significant correlations (p < 0.05) were found between wheat kernel physical properties and pulverizing process of wheat kernel, especially wheat kernel hardness index (obtained on the basis of Single Kernel Characterization System) and vitreousness significantly and positively correlated with the grinding energy indices and the mass fraction of coarse particles (> 0.5 mm). Among the kernel mechanical properties determined on the basis of uniaxial compression test only the rapture force was correlated with the impact grinding results. The results showed also positive and significant relationships between kernel ash content and grinding energy requirements. On the basis of wheat physical properties the multiple linear regression was proposed for predicting the average particle size of pulverized kernel. PMID:25328207

  18. Ultrasonic evaluation of the physical and mechanical properties of granites.

    PubMed

    Vasconcelos, G; Lourenço, P B; Alves, C A S; Pamplona, J

    2008-09-01

    Masonry is the oldest building material that survived until today, being used all over the world and being present in the most impressive historical structures as an evidence of spirit of enterprise of ancient cultures. Conservation, rehabilitation and strengthening of the built heritage and protection of human lives are clear demands of modern societies. In this process, the use of nondestructive methods has become much common in the diagnosis of structural integrity of masonry elements. With respect to the evaluation of the stone condition, the ultrasonic pulse velocity is a simple and economical tool. Thus, the central issue of the present paper concerns the evaluation of the suitability of the ultrasonic pulse velocity method for describing the mechanical and physical properties of granites (range size between 0.1-4.0 mm and 0.3-16.5 mm) and for the assessment of its weathering state. The mechanical properties encompass the compressive and tensile strength and modulus of elasticity, and the physical properties include the density and porosity. For this purpose, measurements of the longitudinal ultrasonic pulse velocity with distinct natural frequency of the transducers were carried out on specimens with different size and shape. A discussion of the factors that induce variations on the ultrasonic velocity is also provided. Additionally, statistical correlations between ultrasonic pulse velocity and mechanical and physical properties of granites are presented and discussed. The major output of the work is the confirmation that ultrasonic pulse velocity can be effectively used as a simple and economical nondestructive method for a preliminary prediction of mechanical and physical properties, as well as a tool for the assessment of the weathering changes of granites that occur during the serviceable life. This is of much interest due to the usual difficulties in removing specimens for mechanical characterization. PMID:18471849

  19. Swiss Atlas of PHYsical properties of Rocks (SAPHYR)

    NASA Astrophysics Data System (ADS)

    Zappone, Alba; Kissling, Eduard

    2015-04-01

    The Swiss Atlas of PHYsical properties of Rocks (SAPHYR), is a multi-year project, funded entirely by Swiss Commission for Geophysics (SGPK), with the aim to compile a comprehensive data set in digital form on physical properties of rocks exposed in Switzerland and surrounding regions. The ultimate goal of SAPHYR is to make these data accessible to an open and wide public including industrial, engineering, land and resource planning companies, as well as academic institutions, or simply people interested in geology. Since the early sixties worldwide many scientists, i.e. geophysicists, petrologists, and engineers, focused their work on laboratory measurements of rocks physical properties, and their relations with microstructures, mineralogical compositions and other rock parameters, in the effort to constrain the geological interpretation of geophysical surveys. Particularly in the years in which seismic reflection and refraction crustal scale projects were investigating the deep structures of the Alps, laboratories capable to reproduce the pressure and temperature ranges of the continental crust were collecting measurements of various rock parameters on a wide variety of lithologies, developing in the meantime more and more sophisticated experimental methodologies. In recent years, the increasing interest of European Countries on non-traditional energy supply, (i.e. Deep Geothermal Energy and shale gas) and CO2 storage renovated the interests in physical characterization of the deep underground. SAPHYR aims to organize all those laboratory data into a geographically referenced database (GIS). The data refer to density, porosity, permeability, and seismic, magnetic, thermal and electric properties. In the past years, effort has been placed on collecting samples and measuring the physical properties of lithologies that were poorly documented in literature. The phase of laboratory measurements is still in progress. Recently, SAPHYR project focused towards developing

  20. Micro/nanoscale continuous printing: direct-writing of wavy micro/nano structures via electrospinning

    NASA Astrophysics Data System (ADS)

    Fang, Feiyu; Du, Zefeng; Zeng, Jun; Zhu, Ziming; Chen, Xin; Chen, Xindu; Lv, Yuanjun; Wang, Han

    2015-07-01

    Micro/nanofibers that are created by direct-writing using an electrospinning (ES) technique have aroused much recent attention, owing to their intriguing physical properties and great potential as building blocks for micro/nanoscale devices. In this work, a wavy direct-writing (WDW) process was developed to directly write wavy micro/nanostructures suitable for the fabrication of micro/nanoscale devices. The low voltage WDW technique is anticipated to be useful for a broad range of applications including flexible/stretchable electronics, micro optoelectronics, nano-antennas, microelectromechanical systems (MEMS), and biomedical engineering.

  1. Investigation on Sintering Mechanism of Nanoscale Tungsten Powder Based on Atomistic Simulation

    NASA Astrophysics Data System (ADS)

    Moitra, Amitava; Kim, Sungho; Kim, Seong-Gon; Park, Seong Jin; German, Randall M.; Horstemeyer, Mark F.

    2010-06-01

    Atomistic simulations focusing on sintering of crystalline tungsten powders at the submicroscopic level are performed to shed light on the processing on the nanoscale powders. The neck growth and shrinkage were calculated during these sintering simulations, so it is possible to extend these results to the global physical property evolution via sintering. The densification and grain growth during sintering were calculated with variations in temperature, pressure, particle configuration, additives, and crystalline misalignment between particles. These findings lay a foundation for a virtual approach to setting the processing cycles and materials design applicable to nanoscale powders.

  2. Entropy and the Shelf Model: A Quantum Physical Approach to a Physical Property

    ERIC Educational Resources Information Center

    Jungermann, Arnd H.

    2006-01-01

    In contrast to most other thermodynamic data, entropy values are not given in relation to a certain--more or less arbitrarily defined--zero level. They are listed in standard thermodynamic tables as absolute values of specific substances. Therefore these values describe a physical property of the listed substances. One of the main tasks of…

  3. Chemical control of physical properties in silicon nitride films

    NASA Astrophysics Data System (ADS)

    Xu, Xiangdong; Zhou, Dong; He, Qiong; Jiang, Yadong; Fan, Taijun; Huang, Long; Ao, Tianhong; He, Shaowei

    2013-06-01

    Amorphous hydrogenated silicon nitride ( a-SiN x H y ) films were prepared by plasma-enhanced chemical vapor deposition (PECVD). The physical properties and chemical structures of the resulting materials were systematically investigated. Results reveal that the a-SiN x H y films similarly consist of four kinds of Si-N groups, including Si3N4, H-Si-N3, H2-Si-N2, and Si3-Si-N. Deposition at 13.56 MHz and 300 ∘C with flow ratio of SiH4/NH3=30/30 sccm leads to the yield of Si0.39N0.38H0.23 films that exhibit excellent properties of high uniformity, high elastic modulus, moderate refractive index and optical band gap, low UV absorption, and ultralow residual stress (-0.17 MPa). Such Si0.39N0.38H0.23 films hold considerable promise for applications in solar cells and infrared sensors. In contrast, an increase of Si or N content in a-SiN x H y films will cause the degradation of the properties, so that the films are unsuitable for solar cells. Moreover, a new conception of network degree was proposed to evaluate and explain the properties of a-SiN x H y films. Particularly, this work discloses the relationships between the chemical structures and physical properties, and suggests a basic approach to the yield of a-SiN x H y films with controlled physical properties.

  4. Spitzer Local Volume Legacy (LVL) SEDs and physical properties

    NASA Astrophysics Data System (ADS)

    Cook, David O.; Dale, Daniel A.; Johnson, Benjamin D.; Van Zee, Liese; Lee, Janice C.; Kennicutt, Robert C.; Calzetti, Daniela; Staudaher, Shawn M.; Engelbracht, Charles W.

    2014-11-01

    We present the panchromatic spectral energy distributions (SEDs) of the Local Volume Legacy (LVL) survey which consists of 258 nearby galaxies (D < 11 Mpc). The wavelength coverage spans the ultraviolet to the infrared (1500 Å-24 μm) which is utilized to derive global physical properties (i.e. star formation rate, stellar mass, internal extinction due to dust). With these data, we find colour-colour relationships and correlated trends between observed and physical properties (i.e. optical magnitudes and dust properties, optical colour and specific star formation rate, and ultraviolet-infrared colour and metallicity). The SEDs are binned by different galaxy properties to reveal how each property affects the observed shape of these SEDs. In addition, due to the volume-limited nature of LVL, we utilize the dwarf-dominated galaxy sample to test star formation relationships established with higher mass galaxy samples. We find good agreement with the star-forming `main-sequence' relationship, but find a systematic deviation in the infrared `main sequence' at low luminosities. This deviation is attributed to suppressed polycyclic aromatic hydrocarbon (PAH) formation in low-metallicity environments and/or the destruction of PAHs in more intense radiation fields occurring near a suggested threshold in star formation rates (sSFR) at a value of log(sSFR) ˜ -10.2.

  5. Chemical and Physical Properties of Hi-Cal-2

    NASA Technical Reports Server (NTRS)

    Spakowski, A. E.; Allen, Harrison, Jr.; Caves, Robert M.

    1955-01-01

    As part of the Navy Project Zip to consider various boron-containing materials as possible high-energy fuels, the chemical and physical properties of Hi-Cal-2 prepared by the Callery Chemical Company were evaluated at the NACA Lewis laboratory. Elemental chemical analysis, heat of combustion, vapor pressure and decomposition, freezing point, density, self ignition temperature, flash point, and blow-out velocity were determined for the fuel. Although the precision of measurement of these properties was not equal to that obtained for hydrocarbons, this special release research memorandum was prepared to make the data available as soon as possible.

  6. Ellipsoids and lightcurves. [for deduction of physical properties of asteroids

    NASA Technical Reports Server (NTRS)

    Connelly, R.; Ostro, S. J.

    1984-01-01

    The determination of the light curve (LC) of a geometrically scattering ellipsoid is considered in relation to the problem of investigating the physical properties of asteroids. A simple concise formula is derived for the area of a projection of an ellipsoid, and this expression is used to obtain a general formula for the projected, visible, illuminated area of a triaxial ellipsoid for arbitrary sun-earth-asteroid geometry. It is found that the LC of an ellipsoid has special properties that can be exploited to test the hypothesis that a given optical or radar LC could be due to a geometrically scattering ellipsoid.

  7. PREFACE: Superconductivity in ultrathin films and nanoscale systems Superconductivity in ultrathin films and nanoscale systems

    NASA Astrophysics Data System (ADS)

    Bianconi, Antonio; Bose, Sangita; Garcia-Garcia, Antonio Miguel

    2012-12-01

    systems. In addition, the role of thermodynamic fluctuations on superconducting properties has been extensively studied in the context of nanoparticles and nanowires both experimentally and theoretically. In the past decade, a lot of work has been initiated in the area of interface superconductivity where different techniques have been demonstrated to tune Tc. Although the progress in this field has deepened our understanding of nanoscale superconductors, there are several open and key questions which need to be addressed. Some of these are: (1) can superconductivity be enhanced and Tc increased in nanostructures with respect to the bulk limit and if so, how can it be controlled? (2) What are the theoretical and experimental limits for the enhancement and control of superconductivity? (3) Can the phenomena identified in conventional nanostructures shed light on phenomena in high Tc superconductors and vice versa? (4) How will the new fundamental physics of superconductivity at the nanoscale promote advances in nanotechnology applications and vice versa? The papers in this focus section reflect the advances made in this field, in particular in nanowires and nanofilms, but also attempt to answer some of the key open questions outlined above. The theoretical papers explore unconventional quantum phenomena such as the role of confinement in the dynamics of single Cooper pairs in isolated grains [1] and Fano resonances in superconducting gaps in multi-condensate superconductors near a 2.5 Lifshitz transition [2]. Here a new emerging class of quantum phenomena of fundamental physics appear at the Bose-BCS crossover in multi-condensate superconductors [2]. Nanosize effects can now be manipulated by controlling defects in layered oxides [3]. A new approach is provided by controlling the self-organization of oxygen interstitials in layered copper oxides that show an intrinsic nanoscale phase separation [4]. In this case a non-trivial distribution of superconducting nanograins

  8. Unique characterization of lunar samples by physical properties

    NASA Technical Reports Server (NTRS)

    Todd, T.; Richter, D. A.; Simmons, G.; Wang, H.

    1973-01-01

    The measurement of compressional velocity, shear velocity, static compressibility, and thermal expansion of (1) a suite of shocked rocks fron the Ries impact in Germany, (2) a suite of samples cracked by thermal cycling to high temperatures, (3) many terrestrial igneous rocks, and (4) lunar basalts, gabbroic anorthosites, and breccias, indicate that shock metamorphism is the primary cause for values of physical properties of lunar rocks being diffferent from their intrinsic values. Large scale thermal metamorphism, thermal cycling between temperatures of lunar day and night, large thermal gradients, or thermal fatigue could possibly cause minor cracking in the top few centimeters of the lunar regolith, but are probably not important mechanism for extensively changing values of physical properties of lunar rocks.-

  9. Charcoal's physical properties are key to understanding its environmental behavior

    NASA Astrophysics Data System (ADS)

    Masiello, Caroline; Brewer, Catherine; Dugan, Brandon; Liu, Zuolin; Gonnermann, Helge; Zygourakis, Kyriacos; Davies, Christian; Panzacchi, Pietro; Gao, Xiaodong; Pyle, Lacey

    2014-05-01

    Charcoal is a highly porous, low density material whose physical properties play a key role in its soil behavior and its environmental fate. In considering biochar, some of its most sought-after environmental effects are a result of its physical characteristics, not its chemical or biological properties. For example, the ability of biochar to retain soil water is widely attributed to its porosity. However, charcoal physical properties are so poorly understood that they are sometimes not characterized at all in the current literature. Here we outline a suite of basic physical properties of charcoal and the likely environmental effects of their variations, with a focus on the interactions between charcoal and water. The most basic physical property of charcoal, its particle size, likely plays a role in its ability to alter the rate of drainage in soils. Particle morphology is also relevant, affecting how particles of soil and char can pack together. Bulk densities of charcoal and soil mixtures can be used to generate a simple estimate of the efficiency of char-soil packing. Charcoal density is an additionally important property and can be measured in a number of ways. Density almost certainly controls the tendency of chars to sink or float, and to erode or remain on the land surface. However, charcoal density can vary by almost a factor of 10 depending on the measurement technique used. We discuss two simple techniques available for measuring char density and the value of information provided by each approach. Finally, we report a simple, fast technique to measure total char porosity, including all pores from nanometers to 10s of micrometers in size. Porosity is at least one of the key controls on the ability of biochar to improve plant-available water, and techniques to measure it have previously been limited to the smallest fraction of pores (N2 sorption) or have required expensive, hazardous procedures (Hg porosimetry). We show that char porosity varies primarily

  10. Role of physical properties of liquids in cavitation erosion

    NASA Technical Reports Server (NTRS)

    Thiruvengadam, A.

    1974-01-01

    The dependence of erosion rates on the ambient temperature of water is discussed. The assumption that the gas inside the bubble is compressed adiabatically during collapse gives better agreement with experiments than the assumption that the gas is isothermally compressed. Acoustic impedance is an important liquid parameter that governs the erosion intensity in vibratory devices. The investigation reveals that the major physical properties of liquids governing the intensity of erosion include density, sound speed, surface tension, vapor pressure, gas content, and nuclei distribution.

  11. Physical Properties of Modified Compositions of Strontium Ruthenates

    NASA Astrophysics Data System (ADS)

    Gulian, Armen; Nikoghosyan, Vahan

    2014-03-01

    We performed systematic research on ceramic materials Sr2RuO4 with Sulfur, Selenium or Tellurium added, in combination with other dopants such as: Au, Pt, Al, Zn, Mn, Ba, Na, Ca, Os, Co, Ni, Fe, and Ir. Data on resistive, magnetic, structural, compositional, morphological and other physical properties are obtained, and the most interesting results are presented, as well as corresponding synthesis conditions. ONR Grants N000141210768 and N000141210244 are acknowledged.

  12. Cesium Eluate Evaporation Solubility and Physical Property Behavior

    SciTech Connect

    Pierce, R.A.

    2003-06-12

    The baseline flowsheet for low activity waste (LAW) in the Hanford River Protection Project (RPP) Waste Treatment Plant (WTP) includes pretreatment of supernatant by removing cesium using ion exchange. When the ion exchange column is loaded, the cesium will be eluted with a 0.5M nitric acid (HNO3) solution to allow the column to be conditioned for re-use. The cesium eluate solution will then be concentrated in a vacuum evaporator to minimize storage volume and recycle HNO3. To prevent the formation of solids during storage of the evaporator bottoms, criteria have been set for limiting the concentration of the evaporator product to 80 percent of saturation at 25 degrees C. A fundamental element of predicting evaporator product solubility is to collect data that can be used to estimate key operating parameters. The data must be able to predict evaporator behavior for a range of eluate concentrations that are evaporated to the point of precipitation. Parameters that were selected for modeling include solubility, density, viscosity, thermal conductivity, and heat capacity. Of central importance is identifying the effect of varying feed components on overall solubility. The point of solubility defines the upper limit for eluate evaporation operations and liquid storage. The solubility point also defines those chemical compounds that have the greatest effects on physical properties. Third, solubility behavior identifies intermediate points where physical property data should be measured for the database. Physical property data (density, viscosity, thermal conductivity, and heat capacity) may be an integral part of tracking evaporator operations as they progress toward their end point. Once the data have been collected, statistical design software can develop mathematical equations that estimate solubility and other physical properties.

  13. Investigation of physical properties of TiO2 nanolayers

    NASA Astrophysics Data System (ADS)

    Struk, Przemyslaw; Pustelny, Tadeusz

    2015-12-01

    We present applications of titanium dioxide wide bandgap oxide semiconductor and its application in integrated optics devices. The paper is focus on research of physical properties TiO2 such as: spectral transmittance, refractive index, extinction coefficient in the UV-VIS-IR range of light as well as surface topography. In addition we show the numerical calculation and optical characterization of fabricated optical planar waveguide based on TiO2.

  14. Synthesis and physical properties of some composite systems

    NASA Astrophysics Data System (ADS)

    Pu, Zhengcai

    There are four major parts in this dissertation: (1) investigation of filler-matrix interactions in poly(dimethylsiloxane)/zeolite (PDMS/zeolite) composites, (2) characterization of mechanical and thermal properties of 3-(trimethoxysilyl)propyl methacrylate coated silica (TPM-Si) filled poly(methyl acrylate) (PMA), (3) small angle x-ray scattering studies of chain penetration into cavities of a zeolite in poly(ethyl acrylate)/zeolite (PEA/zeolite) hybrid material, (4) study of hydrolysis kinetics and stability of bis(triethoxysilyl)ethane (BTESE) in water-ethanol solutions by Fourier transform infrared (FTIR) spectroscopy. In the first part of this study, two types of PDMS/zeolite composites with physically or chemically crosslinked networks were prepared through two different approaches: (1) blending hydroxyl-terminated linear PDMS with zeolite and crosslinking PDMS with tetraethylorthosilicate (TEOS); (2) mixing dichlorodimethylsilane with zeolite, and then hydrolyzing and polymerizing the dichlorodimethylsilane with water. The physical properties of the resulting composites, including mechanical properties, swelling properties, and small angle X-ray (SAXS), were measured and compared. It was shown that the PDMS/zeolite composites having PDMS networks differently crosslinked behave differently in many aspects. In the second part of the study, composites of PMA and of TPM-Si with randomly dispersed, regularly dispersed, and aggregated silica were prepared by blending methyl acrylate and TPM-Si, followed by free radical polymerization. Simple tension properties, equibiaxial extension properties, dynamic mechanical properties, and differential scanning calorimetry (DSC) properties of the resulting composites were investigated. It was shown that well-defined relationships exist between the physical properties of the composites and the preparation processes. In the third part of this study, small angle X-ray scattering (SAXS) intensities of PEA/zeolite hybrids were

  15. Plasmonic Nanostructures for Nano-Scale Bio-Sensing

    PubMed Central

    Chung, Taerin; Lee, Seung-Yeol; Song, Eui Young; Chun, Honggu; Lee, Byoungho

    2011-01-01

    The optical properties of various nanostructures have been widely adopted for biological detection, from DNA sequencing to nano-scale single molecule biological function measurements. In particular, by employing localized surface plasmon resonance (LSPR), we can expect distinguished sensing performance with high sensitivity and resolution. This indicates that nano-scale detections can be realized by using the shift of resonance wavelength of LSPR in response to the refractive index change. In this paper, we overview various plasmonic nanostructures as potential sensing components. The qualitative descriptions of plasmonic nanostructures are supported by the physical phenomena such as plasmonic hybridization and Fano resonance. We present guidelines for designing specific nanostructures with regard to wavelength range and target sensing materials. PMID:22346679

  16. Physical Properties of Biological Entities: An Introduction to the Ontology of Physics for Biology

    PubMed Central

    Cook, Daniel L.; Bookstein, Fred L.; Gennari, John H.

    2011-01-01

    As biomedical investigators strive to integrate data and analyses across spatiotemporal scales and biomedical domains, they have recognized the benefits of formalizing languages and terminologies via computational ontologies. Although ontologies for biological entities—molecules, cells, organs—are well-established, there are no principled ontologies of physical properties—energies, volumes, flow rates—of those entities. In this paper, we introduce the Ontology of Physics for Biology (OPB), a reference ontology of classical physics designed for annotating biophysical content of growing repositories of biomedical datasets and analytical models. The OPB's semantic framework, traceable to James Clerk Maxwell, encompasses modern theories of system dynamics and thermodynamics, and is implemented as a computational ontology that references available upper ontologies. In this paper we focus on the OPB classes that are designed for annotating physical properties encoded in biomedical datasets and computational models, and we discuss how the OPB framework will facilitate biomedical knowledge integration. PMID:22216106

  17. Impact of Methylation on the Physical Properties of DNA

    PubMed Central

    Pérez, Alberto; Castellazzi, Chiara Lara; Battistini, Federica; Collinet, Kathryn; Flores, Oscar; Deniz, Ozgen; Ruiz, Maria Luz; Torrents, David; Eritja, Ramon; Soler-López, Montserrat; Orozco, Modesto

    2012-01-01

    There is increasing evidence for the presence of an alternative code imprinted in the genome that might contribute to gene expression regulation through an indirect reading mechanism. In mammals, components of this coarse-grained regulatory mechanism include chromatin structure and epigenetic signatures, where d(CpG) nucleotide steps are key players. We report a comprehensive experimental and theoretical study of d(CpG) steps that provides a detailed description of their physical characteristics and the impact of cytosine methylation on these properties. We observed that methylation changes the physical properties of d(CpG) steps, having a dramatic effect on enriched CpG segments, such as CpG islands. We demonstrate that methylation reduces the affinity of DNA to assemble into nucleosomes, and can affect nucleosome positioning around transcription start sites. Overall, our results suggest a mechanism by which the basic physical properties of the DNA fiber can explain parts of the cellular epigenetic regulatory mechanisms. PMID:22824278

  18. Anatomy of Nanoscale Propulsion.

    PubMed

    Yadav, Vinita; Duan, Wentao; Butler, Peter J; Sen, Ayusman

    2015-01-01

    Nature supports multifaceted forms of life. Despite the variety and complexity of these forms, motility remains the epicenter of life. The applicable laws of physics change upon going from macroscales to microscales and nanoscales, which are characterized by low Reynolds number (Re). We discuss motion at low Re in natural and synthetic systems, along with various propulsion mechanisms, including electrophoresis, electrolyte diffusiophoresis, and nonelectrolyte diffusiophoresis. We also describe the newly uncovered phenomena of motility in non-ATP-driven self-powered enzymes and the directional movement of these enzymes in response to substrate gradients. These enzymes can also be immobilized to function as fluid pumps in response to the presence of their substrates. Finally, we review emergent collective behavior arising from interacting motile species, and we discuss the possible biomedical applications of the synthetic nanobots and microbots. PMID:26098511

  19. Nanoscale memristive radiofrequency switches

    NASA Astrophysics Data System (ADS)

    Pi, Shuang; Ghadiri-Sadrabadi, Mohammad; Bardin, Joseph C.; Xia, Qiangfei

    2015-06-01

    Radiofrequency switches are critical components in wireless communication systems and consumer electronics. Emerging devices include switches based on microelectromechanical systems and phase-change materials. However, these devices suffer from disadvantages such as large physical dimensions and high actuation voltages. Here we propose and demonstrate a nanoscale radiofrequency switch based on a memristive device. The device can be programmed with a voltage as low as 0.4 V and has an ON/OFF conductance ratio up to 1012 with long state retention. We measure the radiofrequency performance of the switch up to 110 GHz and demonstrate low insertion loss (0.3 dB at 40 GHz), high isolation (30 dB at 40 GHz), an average cutoff frequency of 35 THz and competitive linearity and power-handling capability. Our results suggest that, in addition to their application in memory and computing, memristive devices are also a leading contender for radiofrequency switch applications.

  20. Relationship between physical properties and sensory attributes of carbonated beverages.

    PubMed

    Kappes, S M; Schmidt, S J; Lee, S-Y

    2007-01-01

    Bulk sweeteners provide functional properties in beverages, including sweet taste, bulking, bitter masking, structure, and mouthfeel. Diet beverages come closer to the taste of regular beverages using a blend of high-intensity sweeteners; however, some properties, including bulking, structure, and mouthfeel, remain significantly different. Relating physical properties to sensory characteristics is an important step in understanding why mouthfeel differences are apparent in beverages sweetened with alternative sweeteners compared to bulk sweeteners. The objectives of this research were to (1) measure sweetener profile, Brix, refractive index, viscosity, a(w), carbonation, titratable acidity, and pH of commercial carbonated beverages; and (2) correlate the physical property measurements to descriptive analysis of the beverages. Correlation analysis, partial least squares, canonical correlation analysis, and cluster analysis were used to analyze the data. Brix, viscosity, and sweet taste were highly correlated among one another and were all negatively correlated to a(w). Carbonated and decarbonated pH were highly correlated to each other and were both negatively correlated to mouthcoating. Numbing, burn, bite, and carbonation were highly correlated to total acidity, citric acid, and ascorbic acid and negatively correlated to phosphoric acid. The mouthfeel difference between diet and regular lemon/lime carbonated beverages is small and may be related to overall differences between flavor, acid, and sweetener types and usage levels. This research is significant because it demonstrates the use of both sensory attributes and physical properties to identify types of ingredients and levels that may decrease the mouthfeel perception differences between regular and diet carbonated beverages, which could consequently lead to higher acceptance of diet beverages by the consumers of regular. PMID:17995891

  1. Characterization of the physical properties for solid granular materials

    SciTech Connect

    Tucker, Jonathan R.; Shadle, Lawrence J.; Guenther, Chris; Benyahia, Sofiane; Mei, Joseph S.; Banta, Larry

    2012-01-01

    Accurate prediction of the behavior of a system is strongly governed by the components within that system. For multiphase systems incorporating solid powder-like particles, there are many different physical properties which need to be known to some level of accuracy for proper design, modeling, or data analysis. In the past, the material properties were determined initially as a secondary part of the study or design. In an attempt to provide results with the least level of uncertainty, a procedure was developed and implemented to provide consistent analysis of several different types of materials. The properties that were characterized included particle sizing and size distributions, shape analysis, density (particle, skeletal and bulk), minimum fluidization velocities, void fractions, particle porosity, and assignment within the Geldart Classification. In the methods used for this experiment, a novel form of the Ergun equation was used to determine the bulk void fractions and particle density. Materials of known properties were initially characterized to validate the accuracy and methodology, prior to testing materials of unknown properties. The procedures used yielded valid and accurate results, with a high level of repeatability. A database of these materials has been developed to assist in model validation efforts and future designs. It is also anticipated that further development of these procedures wil be expanded increasing the properties included in the database.

  2. Pure carbon nanoscale devices: Nanotube heterojunctions

    SciTech Connect

    Chico, L.; Crespi, V.H.; Benedict, L.X.; Louie, S.G.; Cohen, M.L. |

    1996-02-01

    Introduction of pentagon-heptagon pair defects into the hexagonal network of a single carbon nanotube can change the helicity of the tube and alter its electronic structure. Using a tight-binding method to calculate the electronic structure of such systems we show that they behave as nanoscale metal/semiconductor or semiconductor/semiconductor junctions. These junctions could be the building blocks of nanoscale electronic devices made entirely of carbon. {copyright} {ital 1996 The American Physical Society.}

  3. Nanoscale Fluid Mechanics and Energy Conversion

    SciTech Connect

    Chen, X; Xu, BX; Liu, L

    2014-05-29

    Under nanoconfinement, fluid molecules and ions exhibit radically different configurations, properties, and energetics from those of their bulk counterparts. These unique characteristics of nanoconfined fluids, along with the unconventional interactions with solids at the nanoscale, have provided many opportunities for engineering innovation. With properly designed nanoconfinement, several nanofluidic systems have been devised in our group in the past several years to achieve energy conversion functions with high efficiencies. This review is dedicated to elucidating the unique characteristics of nanofluidics, introducing several novel nanofluidic systems combining nanoporous materials with functional fluids, and to unveiling their working mechanisms. In all these systems, the ultra-large surface area available in nanoporous materials provides an ideal platform for seamlessly interfacing with nanoconfined fluids, and efficiently converting energy between the mechanical, thermal, and electrical forms. These systems have been demonstrated to have great potentials for applications including energy dissipation/absorption, energy trapping, actuation, and energy harvesting. Their efficiencies can be further enhanced by designing efforts based upon improved understanding of nanofluidics, which represents an important addition to classical fluid mechanics. Through the few systems exemplified in this review, the emerging research field of nanoscale fluid mechanics may promote more exciting nanofluidic phenomena and mechanisms, with increasing applications by encompassing aspects of mechanics, materials, physics, chemistry, biology, etc.

  4. New directions for nanoscale thermoelectric materials research

    NASA Technical Reports Server (NTRS)

    Dresselhaus, M. S.; Chen, G.; Tang, M. Y.; Yang, R. G.; Lee, H.; Wang, D. Z.; Ren, F.; Fleurial, J. P.; Gogna, P.

    2005-01-01

    Many of the recent advances in enhancing the thermoelectric figure of merit are linked to nanoscale phenomena with both bulk samples containing nanoscale constituents and nanoscale materials exhibiting enhanced thermoelectric performance in their own right. Prior theoretical and experimental proof of principle studies on isolated quantum well and quantum wire samples have now evolved into studies on bulk samples containing nanostructured constituents. In this review, nanostructural composites are shown to exhibit nanostructures and properties that show promise for thermoelectric applications. A review of some of the results obtained to date are presented.

  5. Exploring Carbon Nanotubes for Nanoscale Devices

    NASA Technical Reports Server (NTRS)

    Han, Jie; Dai; Anantram; Jaffe; Saini, Subhash (Technical Monitor)

    1998-01-01

    Carbon nanotubes (CNTs) are shown to promise great opportunities in nanoelectronic devices and nanoelectromechanical systems (NEMS) because of their inherent nanoscale sizes, intrinsic electric conductivities, and seamless hexagonal network architectures. I present our collaborative work with Stanford on exploring CNTs for nanodevices in this talk. The electrical property measurements suggest that metallic tubes are quantum wires. Furthermore, two and three terminal CNT junctions have been observed experimentally. We have proposed and studied CNT-based molecular switches and logic devices for future digital electronics. We also have studied CNTs based NEMS inclusing gears, cantilevers, and scanning probe microscopy tips. We investigate both chemistry and physics based aspects of the CNT NEMS. Our results suggest that CNT have ideal stiffness, vibrational frequencies, Q-factors, geometry-dependent electric conductivities, and the highest chemical and mechanical stabilities for the NEMS. The use of CNT SPM tips for nanolithography is presented for demonstration of the advantages of the CNT NEMS.

  6. HYDRAULIC AND PHYSICAL PROPERTIES OF SALTSTONE GROUTS AND VAULT CONCRETES

    SciTech Connect

    Dixon, K; John Harbour, J; Mark Phifer, M

    2008-11-25

    The Saltstone Disposal Facility (SDF), located in the Z-Area of the Savannah River Site (SRS), is used for the disposal of low-level radioactive salt solution. The SDF currently contains two vaults: Vault 1 (6 cells) and Vault 4 (12 cells). Additional disposal cells are currently in the design phase. The individual cells of the saltstone facility are filled with saltstone. Saltstone is produced by mixing the low-level radioactive salt solution, with blast furnace slag, fly ash, and cement (dry premix) to form a dense, micro-porous, monolithic, low-level radioactive waste form. The saltstone is pumped into the disposal cells where it subsequently solidifies. Significant effort has been undertaken to accurately model the movement of water and contaminants through the facility. Key to this effort is an accurate understanding of the hydraulic and physical properties of the solidified saltstone. To date, limited testing has been conducted to characterize the saltstone. The primary focus of this task was to estimate the hydraulic and physical properties of three types of saltstone and two vault concretes. The saltstone formulations included saltstone premix batched with (1) Deliquification, Dissolution, and Adjustment (DDA) salt simulant (w/pm 0.60), (2) Actinide Removal Process (ARP)/Modular Caustic Side Solvent Extraction Unit (MCU) salt simulant (w/pm 0.60), and (3) Salt Waste Processing Facility (SWPF) salt simulant (w/pm 0.60). The vault concrete formulations tested included the Vault 1/4 concrete and two variations of the Vault 2 concrete (Mix 1 and Mix 2). Wet properties measured for the saltstone formulations included yield stress, plastic viscosity, wet unit weight, bleed water volume, gel time, set time, and heat of hydration. Hydraulic and physical properties measured on the cured saltstone and concrete samples included saturated hydraulic conductivity, moisture retention, compressive strength, porosity, particle density, and dry bulk density. These properties

  7. Nanoscale magnetism and novel electronic properties of a bilayer bismuth(111) film with vacancies and chemical doping.

    PubMed

    Sahoo, M P K; Zhang, Yajun; Wang, Jie

    2016-07-27

    Magnetically doped topological insulators (TIs) exhibit several exotic phenomena including the magnetoelectric effect and quantum anomalous Hall effect. However, from an experimental perspective, incorporation of spin moment into 3D TIs is still challenging. Thus, instead of 3D TIs, the 2D form of TIs may open up new opportunities to induce magnetism. Based on first principles calculations, we demonstrate a novel strategy to realize robust magnetism and exotic electronic properties in a 2D TI [bilayer Bi(111) film: abbreviated as Bi(111)]. We examine the magnetic and electronic properties of Bi(111) with defects such as bismuth monovacancies (MVs) and divacancies (DVs), and these defects decorated with 3d transition metals (TMs). It has been observed that the MV in Bi(111) can induce novel half metallicity with a net magnetic moment of 1 μB. The origin of half metallicity and magnetism in MV/Bi(111) is further explained by the passivation of the σ-dangling bonds near the defect site. Furthermore, in spite of the nonmagnetic nature of DVs, the TMs (V, Cr, Mn, and Fe) trapped at the 5/8/5 defect structure of DVs can not only yield a much higher spin moment than those trapped at the MVs but also display intriguing electronic properties such as metallic, semiconducting and spin gapless semiconducting properties. The predicted magnetic and electronic properties of TM/DV/Bi(111) systems are explained through density of states, spin density distribution and Bader charge analysis. PMID:27406933

  8. PREFACE: Superconductivity in ultrathin films and nanoscale systems Superconductivity in ultrathin films and nanoscale systems

    NASA Astrophysics Data System (ADS)

    Bianconi, Antonio; Bose, Sangita; Garcia-Garcia, Antonio Miguel

    2012-12-01

    systems. In addition, the role of thermodynamic fluctuations on superconducting properties has been extensively studied in the context of nanoparticles and nanowires both experimentally and theoretically. In the past decade, a lot of work has been initiated in the area of interface superconductivity where different techniques have been demonstrated to tune Tc. Although the progress in this field has deepened our understanding of nanoscale superconductors, there are several open and key questions which need to be addressed. Some of these are: (1) can superconductivity be enhanced and Tc increased in nanostructures with respect to the bulk limit and if so, how can it be controlled? (2) What are the theoretical and experimental limits for the enhancement and control of superconductivity? (3) Can the phenomena identified in conventional nanostructures shed light on phenomena in high Tc superconductors and vice versa? (4) How will the new fundamental physics of superconductivity at the nanoscale promote advances in nanotechnology applications and vice versa? The papers in this focus section reflect the advances made in this field, in particular in nanowires and nanofilms, but also attempt to answer some of the key open questions outlined above. The theoretical papers explore unconventional quantum phenomena such as the role of confinement in the dynamics of single Cooper pairs in isolated grains [1] and Fano resonances in superconducting gaps in multi-condensate superconductors near a 2.5 Lifshitz transition [2]. Here a new emerging class of quantum phenomena of fundamental physics appear at the Bose-BCS crossover in multi-condensate superconductors [2]. Nanosize effects can now be manipulated by controlling defects in layered oxides [3]. A new approach is provided by controlling the self-organization of oxygen interstitials in layered copper oxides that show an intrinsic nanoscale phase separation [4]. In this case a non-trivial distribution of superconducting nanograins

  9. The number comb for a soil physical properties dynamic measurement

    NASA Astrophysics Data System (ADS)

    Olechko, K.; Patiño, P.; Tarquis, A. M.

    2012-04-01

    We propose the prime numbers distribution extracted from the soil digital multiscale images and some physical properties time series as the precise indicator of the spatial and temporal dynamics under soil management changes. With this new indicator the soil dynamics can be studied as a critical phenomenon where each phase transition is estimated and modeled by the graph partitioning induced phase transition. The critical point of prime numbers distribution was correlated with the beginning of Andosols, Vertisols and saline soils physical degradation under the unsustainable soil management in Michoacan, Guanajuato and Veracruz States of Mexico. The data banks corresponding to the long time periods (between 10 and 28 years) were statistically compared by RISK 5.0 software and our own algorithms. Our approach makes us able to distill free-form natural laws of soils physical properties dynamics directly from the experimental data. The Richter (1987) and Schmidt and Lipson (2009) original approaches were very useful to design the algorithms to identify Hamiltonians, Lagrangians and other laws of geometric and momentum conservation especially for erosion case.

  10. EXAFS and XANES analysis of oxides at the nanoscale

    PubMed Central

    Kuzmin, Alexei; Chaboy, Jesús

    2014-01-01

    Worldwide research activity at the nanoscale is triggering the appearance of new, and frequently surprising, materials properties in which the increasing importance of surface and interface effects plays a fundamental role. This opens further possibilities in the development of new multifunctional materials with tuned physical properties that do not arise together at the bulk scale. Unfortunately, the standard methods currently available for solving the atomic structure of bulk crystals fail for nanomaterials due to nanoscale effects (very small crystallite sizes, large surface-to-volume ratio, near-surface relaxation, local lattice distortions etc.). As a consequence, a critical reexamination of the available local-structure characterization methods is needed. This work discusses the real possibilities and limits of X-ray absorption spectroscopy (XAS) analysis at the nanoscale. To this end, the present state of the art for the interpretation of extended X-ray absorption fine structure (EXAFS) is described, including an advanced approach based on the use of classical molecular dynamics and its application to nickel oxide nanoparticles. The limits and possibilities of X-ray absorption near-edge spectroscopy (XANES) to determine several effects associated with the nanocrystalline nature of materials are discussed in connection with the development of ZnO-based dilute magnetic semiconductors (DMSs) and iron oxide nanoparticles. PMID:25485137

  11. Magnetic properties of nano-scale hematite, α-Fe{sub 2}O{sub 3}, studied by time-of-flight inelastic neutron spectroscopy

    SciTech Connect

    Hill, Adrian H.; Jacobsen, Henrik Holm, Sonja L.; Lefmann, Kim; Stewart, J. Ross; Jiao, Feng; Jensen, Niels P.; Mutka, Hannu; Seydel, Tilo; Harrison, Andrew

    2014-01-28

    Samples of nanoscale hematite, α-Fe{sub 2}O{sub 3}, with different surface geometries and properties have been studied with inelastic time-of-flight neutron scattering. The 15 nm diameter nanoparticles previously shown to have two collective magnetic excitation modes in separate triple-axis neutron scattering studies have been studied in further detail using the advantage of a large detector area, high resolution, and large energy transfer range of the IN5 TOF spectrometer. A mesoporous hematite sample has also been studied, showing similarities to that of the nanoparticle sample and bulk α-Fe{sub 2}O{sub 3}. Analysis of these modes provides temperature dependence of the magnetic anisotropy coefficient along the c-axis, κ{sub 1}. This is shown to remain negative throughout the temperature range studied in both samples, providing an explanation for the previously observed suppression of the Morin transition in the mesoporous material. The values of this anisotropy coefficient are found to lie between those of bulk and nano-particulate samples, showing the hybrid nature of the mesoporous 3-dimensional structure.

  12. In situ nanoscale refinement by highly controllable etching of the (111) silicon crystal plane and its influence on the enhanced electrical property of a silicon nanowire

    NASA Astrophysics Data System (ADS)

    Yibin, Gong; Pengfei, Dai; Anran, Gao; Tie, Li; Ping, Zhou; Yuelin, Wang

    2011-12-01

    Nanoscale refinement on a (100) oriented silicon-on-insulator (SOI) wafer was introduced by using tetra-methyl-ammonium hydroxide (TMAH, 25 wt%) anisotropic silicon etchant, with temperature kept at 50 °C to achieve precise etching of the (111) crystal plane. Specifically for a silicon nanowire (SiNW) with oxide sidewall protection, the in situ TMAH process enabled effective size reduction in both lateral (2.3 nm/min) and vertical (1.7 nm/min) dimensions. A sub-50 nm SiNW with a length of microns with uniform triangular cross-section was achieved accordingly, yielding enhanced field effect transistor (FET) characteristics in comparison with its 100 nm-wide pre-refining counterpart, which demonstrated the feasibility of this highly controllable refinement process. Detailed examination revealed that the high surface quality of the (111) plane, as well as the bulk depletion property should be the causes of this electrical enhancement, which implies the great potential of the as-made cost-effective SiNW FET device in many fields.

  13. Elasto-plastic characteristics and mechanical properties of as-sprayed 8 mol% yttria-stabilized zirconia coating under nano-scales measured by nanoindentation

    NASA Astrophysics Data System (ADS)

    Luo, J. M.; Dai, C. Y.; Shen, Y. G.; Mao, W. G.

    2014-08-01

    The elasto-plastic characteristics and mechanical properties of as-received 8 mol% Y2O3-ZrO2 (8YSZ) coatings were studied by nanoindentation at ultra-low loads with a Berkovich indenter at room temperature. All experimental data including hardness H and elastic modulus E were analyzed by the Weibull statistical method due to the porous and heterogeneous nature of the tested samples. It was found that the hardness firstly exhibits interesting reverse indentation size effect, and then shows normal indentation size effect within different indentation scales. The average elastic modulus of 8YSZ was estimated as 214.8 ± 13.2 GPa. In order to reveal the elasto-plastic characteristics of 8YSZ at nano-scales, the distribution of resolved shear stresses underneath the indenter tip region was evaluated by Hertzian contact theory when the deformation behavior of 8YSZ changed from fully elastic to elasto-plastic stages. The results shed light on understanding possible foreign object damage mechanisms of thermal barrier coating systems.

  14. Magnetic properties of nano-scale hematite, α-Fe2O3, studied by time-of-flight inelastic neutron spectroscopy

    NASA Astrophysics Data System (ADS)

    Hill, Adrian H.; Jacobsen, Henrik; Stewart, J. Ross; Jiao, Feng; Jensen, Niels P.; Holm, Sonja L.; Mutka, Hannu; Seydel, Tilo; Harrison, Andrew; Lefmann, Kim

    2014-01-01

    Samples of nanoscale hematite, α-Fe2O3, with different surface geometries and properties have been studied with inelastic time-of-flight neutron scattering. The 15 nm diameter nanoparticles previously shown to have two collective magnetic excitation modes in separate triple-axis neutron scattering studies have been studied in further detail using the advantage of a large detector area, high resolution, and large energy transfer range of the IN5 TOF spectrometer. A mesoporous hematite sample has also been studied, showing similarities to that of the nanoparticle sample and bulk α-Fe2O3. Analysis of these modes provides temperature dependence of the magnetic anisotropy coefficient along the c-axis, κ1. This is shown to remain negative throughout the temperature range studied in both samples, providing an explanation for the previously observed suppression of the Morin transition in the mesoporous material. The values of this anisotropy coefficient are found to lie between those of bulk and nano-particulate samples, showing the hybrid nature of the mesoporous 3-dimensional structure.

  15. Probing the nanoscale interaction forces and elastic properties of organic and inorganic materials using force-distance (F-D) spectroscopy

    NASA Astrophysics Data System (ADS)

    Vincent, Abhilash

    Due to their therapeutic applications such as radical scavenging, MRI contrast imaging, Photoluminescence imaging, drug delivery, etc., nanoparticles (NPs) have a significant importance in bio-nanotechnology. The reason that prevents the utilizing NPs for drug delivery in medical field is mostly due to their biocompatibility issues (incompatibility can lead to toxicity and cell death). Changes in the surface conditions of NPs often lead to NP cytotoxicity. Investigating the role of NP surface properties (surface charges and surface chemistry) on their interactions with biomolecules (Cells, protein and DNA) could enhance the current understanding of NP cytotoxicity. Hence, it is highly beneficial to the nanotechnology community to bring more attention towards the enhancement of surface properties of NPs to make them more biocompatible and less toxic to biological systems. Surface functionalization of NPs using specific ligand biomolecules have shown to enhance the protein adsorption and cellular uptake through more favorable interaction pathways. Cerium oxide NPs (CNPs also known as nanoceria) are potential antioxidants in cell culture models and understanding the nature of interaction between cerium oxide NPs and biological proteins and cells are important due to their therapeutic application (especially in site specific drug delivery systems). The surface charges and surface chemistry of CNPs play a major role in protein adsorption and cellular uptake. Hence, by tuning the surface charges and by selecting proper functional molecules on the surface, CNPs exhibiting strong adhesion to biological materials can be prepared. By probing the nanoscale interaction forces acting between CNPs and protein molecules using Atomic Force Microscopy (AFM) based force-distance (F-D) spectroscopy, the mechanism of CNP-protein adsorption and CNP cellular uptake can be understood more quantitatively. The work presented in this dissertation is based on the application of AFM in

  16. Development and Evaluation of Nanoscale Sorbents for Mercury Capture from Warm Fuel Gas

    SciTech Connect

    Raja A. Jadhav; Howard Meyer; Slawomir Winecki

    2006-03-01

    Several nanocrystalline sorbents were synthesized by GTI's subcontractor NanoScale Materials, Inc. (NanoScale) and submitted to GTI for evaluation. A total of seventeen sorbent formulations were synthesized and characterized by NanoScale, including four existing sorbent formulations (NanoActive{trademark} TiO{sub 2}, NanoActive CeO{sub 2}, NanoActive ZnO, and NanoActive CuO), three developmental nanocrystalline metal oxides (MnO{sub 2}, MoO{sub 3}, and Cr{sub 2}O{sub 3}), and ten supported forms of metal oxides. These sorbents were characterized for physical and chemical properties using a variety of analytical equipments, which confirmed their nanocrystalline structure.

  17. Super-Resolution Molecular and Functional Imaging of Nanoscale Architectures in Life and Materials Science

    PubMed Central

    Habuchi, Satoshi

    2014-01-01

    Super-resolution (SR) fluorescence microscopy has been revolutionizing the way in which we investigate the structures, dynamics, and functions of a wide range of nanoscale systems. In this review, I describe the current state of various SR fluorescence microscopy techniques along with the latest developments of fluorophores and labeling for the SR microscopy. I discuss the applications of SR microscopy in the fields of life science and materials science with a special emphasis on quantitative molecular imaging and nanoscale functional imaging. These studies open new opportunities for unraveling the physical, chemical, and optical properties of a wide range of nanoscale architectures together with their nanostructures and will enable the development of new (bio-)nanotechnology. PMID:25152893

  18. QA/QC requirements for physical properties sampling and analysis

    SciTech Connect

    Innis, B.E.

    1993-07-21

    This report presents results of an assessment of the available information concerning US Environmental Protection Agency (EPA) quality assurance/quality control (QA/QC) requirements and guidance applicable to sampling, handling, and analyzing physical parameter samples at Comprehensive Environmental Restoration, Compensation, and Liability Act (CERCLA) investigation sites. Geotechnical testing laboratories measure the following physical properties of soil and sediment samples collected during CERCLA remedial investigations (RI) at the Hanford Site: moisture content, grain size by sieve, grain size by hydrometer, specific gravity, bulk density/porosity, saturated hydraulic conductivity, moisture retention, unsaturated hydraulic conductivity, and permeability of rocks by flowing air. Geotechnical testing laboratories also measure the following chemical parameters of soil and sediment samples collected during Hanford Site CERCLA RI: calcium carbonate and saturated column leach testing. Physical parameter data are used for (1) characterization of vadose and saturated zone geology and hydrogeology, (2) selection of monitoring well screen sizes, (3) to support modeling and analysis of the vadose and saturated zones, and (4) for engineering design. The objectives of this report are to determine the QA/QC levels accepted in the EPA Region 10 for the sampling, handling, and analysis of soil samples for physical parameters during CERCLA RI.

  19. Tuning Physical Properties of Nanocomplexes Through Microfluidics-Assisted Confinement

    PubMed Central

    Ho, Yi-Ping; Grigsby, Christopher L.; Zhao, Feng; Leong, Kam W.

    2011-01-01

    The future of genetic medicine hinges on successful intracellular delivery of nucleic acid-based therapeutics. While significant effort has concentrated on developing nano-carriers to improve the delivery aspects, scant attention has been paid to the synthetic process of poorly controlled nanocomplex formation. Proposed here is a reliable system to better control the complexation process, and thus the physical properties of the nanocomplexes, through microfluidics-assisted confinement (MAC) in picoliter droplets. We show that these homogeneous MAC-synthesized nanocomplexes exhibit narrower size distribution, lower cytotoxicity, and higher transfection efficiency compared to their bulk-synthesized counterparts. MAC represents a physical approach to control the energetic self-assembly of polyelectrolytes, thereby complementing the chemical innovations in nano-carrier design to optimize nucleic acid and peptide delivery. PMID:21506589

  20. Measurements of physical properties of model Titan atmospheres

    NASA Technical Reports Server (NTRS)

    Scattergood, T. W.; Chang, S.; Mckay, C.; Ohara, B.; Carle, G.

    1986-01-01

    One aspect of the study of Titan's atmosphere is the elucidation of the chemical and physical nature of the aerosols. In order to facilitate this, a program to produce laboratory synthesized model materials for Titan's aerosol and to study their chemical and physical properties is now in progress. Various processes, including electric discharge, photolysis by ultraviolet light, and irradiation by energetic particles, will be used to produce the materials. A first set of experiments where a nominal Titan mixture (97%N2, 3% CH4, 0.2% H2) was subjected to pulsed high temperature shocks yielded a reddish brown waxy solid. This material was subjected to pyrolysis/gas chromatography, a technique that has been proposed as a method for analysis of the Titan aerosols. Preliminary results show the material to consist of simple hydrocarbons but little else, at least up to temperatures of 600 C. Since the material was colored, compounds other than those mentioned above must be present.

  1. Growth and physical properties of molecular organic thin films

    NASA Astrophysics Data System (ADS)

    Fraxedas, J.

    2004-04-01

    Highly-oriented polycrystalline thin films of molecular organic materials consisting of small molecules can be easily obtained by physical and chemical vapour deposition methods. The crystallographic phase, orientation and morphology of the films critically depend on the interface and on the kinetics of growth and can be controlled, to a certain extent, by a judicious selection of the substrates and of the growth parameters. This article shortly explores the formation of organic-inorganic heterostructures as a function of coverage: from the most fundamental case, a single molecule on a surface, to thick films (thickness ˜ 1 μ m). The case of high-quality thick TTF-TCNQ films exemplifies the fact that the derived physical properties are essentially identical to those obtained from single crystals. Key words. Molecular organic materials thin films interfaces.

  2. Progress in physical properties of Chinese stock markets

    NASA Astrophysics Data System (ADS)

    Liang, Yuan; Yang, Guang; Huang, Ji-Ping

    2013-08-01

    In the past two decades, statistical physics was brought into the field of finance, applying new methods and concepts to financial time series and developing a new interdiscipline "econophysics". In this review, we introduce several commonly used methods for stock time series in econophysics including distribution functions, correlation functions, detrended fluctuation analysis method, detrended moving average method, and multifractal analysis. Then based on these methods, we review some statistical properties of Chinese stock markets including scaling behavior, long-term correlations, cross-correlations, leverage effects, antileverage effects, and multifractality. Last, based on an agent-based model, we develop a new option pricing model — financial market model that shows a good agreement with the prices using real Shanghai Index data. This review is helpful for people to understand and research statistical physics of financial markets.

  3. Finding human promoter groups based on DNA physical properties

    NASA Astrophysics Data System (ADS)

    Zeng, Jia; Cao, Xiao-Qin; Zhao, Hongya; Yan, Hong

    2009-10-01

    DNA rigidity is an important physical property originating from the DNA three-dimensional structure. Although the general DNA rigidity patterns in human promoters have been investigated, their distinct roles in transcription are largely unknown. In this paper, we discover four highly distinct human promoter groups based on similarity of their rigidity profiles. First, we find that all promoter groups conserve relatively rigid DNAs at the canonical TATA box [a consensus TATA(A/T)A(A/T) sequence] position, which are important physical signals in binding transcription factors. Second, we find that the genes activated by each group of promoters share significant biological functions based on their gene ontology annotations. Finally, we find that these human promoter groups correlate with the tissue-specific gene expression.

  4. Predicting Macroscale Physical Properties Using Microscale Image Data

    NASA Astrophysics Data System (ADS)

    Fredrich, J. T.

    2003-12-01

    Geologic materials, including tight crystalline rocks, shales, and weakly consolidated sandstones and limestones, exhibit geometrically complex microscale structures that control physical and mechanical properties at the macroscale. The past decade has seen remarkable development of several new techniques that enable high-resolution three-dimensional imaging of the pore structure of complex geomaterials. This, coupled with advances in numerical simulation methods, computer hardware, and development of fast computer architectures, provides unprecedented opportunities for the prediction of bulk physical and/or mechanical properties directly from microscale image data. We present data obtained using the two highest fidelity methods for 3D imaging, synchrotron computed microtomography and laser scanning microscopy, and discuss the advantages and disadvantages that each method presents in the specific context of microscale imaging and subsequent use of 3D image data in numerical simulations. We also contrast the application of these modern techniques with conventional serial sectioning techniques. We directly apply the image data in massively parallel numerical simulations of single phase fluid flow. Using data obtained for several natural and synthetic sandstones at a range of resolutions and encompassing different solid volumes, we explore fundamental issues related to representative volumes and length scales necessary to characterize geometrically complex porous media and enable accurate prediction of physical properties at the macroscale. This work was performed at Sandia National Laboratories funded by the US DOE under Contract DE-AC04-94AL85000. Sandia is a multiprogam laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy.

  5. Physical properties of coriander seeds at different moisture content

    NASA Astrophysics Data System (ADS)

    Balasubramanian, S.; Singh, K. K.; Kumar, R.

    2012-10-01

    Physical properties of coriander seeds were determined at moisture content of 3.5-17.7%, d.b. The major axis and 1 000 seeds mass were found to decrease nonlinearly with increase in seed moisture. The medium and minor axes, geometric mean diameter, sphericity, unit volume, surface area and angle of repose increased linearly. Bulk density decreased linearly, however the true density increased non-linearly. The coefficient of static friction increased nonlinearly for different surfaces with increase in moisture level and its maximum was found for plywood surface. The rupture force and energy absorbed decreased linearly with increasing moisture content.

  6. The clouds of Venus. [physical and chemical properties

    NASA Technical Reports Server (NTRS)

    Young, A. T.

    1975-01-01

    The physical and chemical properties of the clouds of Venus are reviewed, with special emphasis on data that are related to cloud dynamics. None of the currently-popular interpretations of cloud phenomena on Venus is consistent with all the data. Either a considerable fraction of the observational evidence is faulty or has been misinterpreted, or the clouds of Venus are much more complex than the current simplistic models. Several lines of attack are suggested to resolve some of the contradictions. A sound understanding of the clouds appears to be several years in the future.

  7. Physical properties of alternatives to the fully halogenated chlorofluorocarbons

    NASA Technical Reports Server (NTRS)

    Mclinden, Mark O.

    1990-01-01

    Presented here are recommended values and correlations of selected physical properties of several alternatives to the fully halogenated chlorocarbons. The quality of the data used in this compilation varies widely, ranging from well-documented, high accuracy measurements from published sources to completely undocumented values listed on anonymous data sheets. That some of the properties for some fluids are available only from the latter type of source is clearly not the desired state of affairs. While some would reject all such data, the compilation given here is presented in the spirit of laying out the present state of knowledge and making available a set of data in a timely manner, even though its quality is sometimes uncertain. The correlations presented here are certain to change quickly as additional information becomes available.

  8. Physical properties of superconducting single crystal iron sulfide

    NASA Astrophysics Data System (ADS)

    Rodriguez, Efrain E.; Borg, Christopher K. H.; Zhou, Xiuquan; Paglione, Johnpierre; University of Maryland Collaboration

    Recently, the simple binary tetragonal iron sulfide, FeS, was found to be a superconductor with a Tc = 5 K. We have prepared single crystals of tetragonal iron sulfide through hydrothermal de-intercalation of KxFe2-yS2. The KxFe2-yS2 single crystal precursors were grown by slow cooling of stoichiometric melts of K, Fe and S. The silver, plate-like FeS single crystals were highly crystalline with a superconducting transition temperature (Tc) of 4 K. The high quality of the FeS crystals revealed highly anisotropic nature of the magnetic and electronic properties intrinsic to FeS. The physical properties and thermal stability of single crystal FeS will be discussed in detail.

  9. Physical properties of inorganic PMW-PNN-PZT ceramics

    NASA Astrophysics Data System (ADS)

    Sin, Sang-Hoon; Yoo, Ju-hyun; Kim, Yong-Jin; Baek, Sam-ki; Ha, Jun-Soo; No, Chung-Han; Song, Hyun-Seon; Shin, Dong-Chan

    2015-07-01

    In this work, inorganic Pb(Mg1/2W1/2)0.03(Ni1/3Nb2/3)x(Zr0.5Ti0.5)0.97-xO3 (x = 0.02 ∼ 0.12) composition ceramics were fabricated by the conventional solid state reaction method. And then their micro structure and ferroelectric properties were investigated according to the amount of PNN substitution. Small amounts of Li2CO3 and CaCO3 were used in order to decrease the sintering temperature of the ceramics. The 0.10 mol PNN-substituted PMW-PNN- PZT ceramics sintered at 920°C showed the excellent physical properties of piezoelectric constant (d33), electromechanical coupling factor (kp), mechanical quality coefficient (Qm), and dielectric constant of 566 pC/N, 0.61, 73, and 2183, respectively.

  10. Physical properties of some Sn-based melts

    NASA Astrophysics Data System (ADS)

    Sidorov, V.; Uporov, S.; Rozitsina, E.; Yagodin, D.; Grushevskij, K.; Ilinykh, N.

    2011-05-01

    The physical properties (viscosity, density, electroresistivity and magnetic susceptibility) of pure tin, copper, silver, some binary (Sn - Ag, Sn - Cu, Sn - Bi, Sn - Zn) and ternary (Sn-Ag-Cu, Sn-BiAg, Sn-Bi-Zn) alloys with near eutectic compositions are investigated in wide temperature ranges. The irreversible decrease of viscosity in pure tin melt is discovered at 820 °С during heating. The similar anomaly with the following hysteresis of dynamic viscosity was fixed for binary and ternary alloys but at higher temperatures - 900 °С and 950 °С respectively. For all the systems it was shown that the alloys with eutectic compositions differ significantly in their electric and magnetic properties from hypo- and hypereutectic ones. Qualitative and quantitative metallographic analysis for Sn-3.8wt.%Ag-0.7wt.%Cu samples, heated low and above characteristic temperatures, showed the influence of melt overheating on crystallization kinetics.

  11. Thermo-Physical Properties of Intermediate Temperature Heat Pipe Fluids

    NASA Technical Reports Server (NTRS)

    Beach, Duane E. (Technical Monitor); Devarakonda, Angirasa; Anderson, William G.

    2005-01-01

    Heat pipes are among the most promising technologies for space radiator systems. The paper reports further evaluation of potential heat pipe fluids in the intermediate temperature range of 400 to 700 K in continuation of two recent reports. More thermo-physical property data are examined. Organic, inorganic, and elemental substances are considered. The evaluation of surface tension and other fluid properties are examined. Halides are evaluated as potential heat pipe fluids. Reliable data are not available for all fluids and further database development is necessary. Many of the fluids considered are promising candidates as heat pipe fluids. Water is promising as a heat pipe fluid up to 500 to 550 K. Life test data for thermo-chemical compatibility are almost non-existent.

  12. Physical properties and compression loading behaviour of corn seed

    NASA Astrophysics Data System (ADS)

    Babić, Lj.; Radojèin, M.; Pavkov, I.; Babić, M.; Turan, J.; Zoranović, M.; Stanišić, S.

    2013-03-01

    The aim of this study was to acquire data on the physical properties and compression loading behaviour of seed of six corn hybrid varieties. The mean values of length, width, thickness, geometric diameter, surface area, porosity, single kernel mass, sphericity, bulk and true density, 1 000 kernelmass and coefficient of friction were studied at single level of corn seed moisture content. The calculated secant modulus of elasticity during compressive loading for dent corn was 0.995 times that of the semi-flint type; there were no significant differences in the value of this mechanical property between semi-flint and dent corn varieties. The linear model showed a decreasing tendency of secant modulus of elasticity for all hybrids as the moisture content of seeds increased.

  13. Sodium-ion storage properties of nickel sulfide hollow nanospheres/reduced graphene oxide composite powders prepared by a spray drying process and the nanoscale Kirkendall effect

    NASA Astrophysics Data System (ADS)

    Park, G. D.; Cho, J. S.; Kang, Y. C.

    2015-10-01

    Spray-drying and the nanoscale Kirkendall diffusion process are used to prepare nickel sulfide hollow nanospheres/reduced graphene oxide (rGO) composite powders with excellent Na-ion storage properties. Metallic Ni nanopowder-decorated rGO powders, formed as intermediate products, are transformed into composite powders of nickel sulfide hollow nanospheres/rGO with mixed crystal structures of Ni3S2 and Ni9S8 phases by the sulfidation process under H2S gas. Nickel sulfide/rGO composite powders with the main crystal structure of Ni3S2 are also prepared as comparison samples by the direct sulfidation of nickel acetate-graphene oxide (GO) composite powders obtained by spray-drying. In electrochemical properties, the discharge capacities at the 150th cycle of the nickel sulfide/rGO composite powders prepared by sulfidation of the Ni/rGO composite and nickel acetate/GO composite powders at a current density of 0.3 A g-1 are 449 and 363 mA h g-1, respectively; their capacity retentions, calculated from the tenth cycle, are 100 and 87%. The nickel sulfide hollow nanospheres/rGO composite powders possess structural stability over repeated Na-ion insertion and extraction processes, and also show excellent rate performance for Na-ion storage.Spray-drying and the nanoscale Kirkendall diffusion process are used to prepare nickel sulfide hollow nanospheres/reduced graphene oxide (rGO) composite powders with excellent Na-ion storage properties. Metallic Ni nanopowder-decorated rGO powders, formed as intermediate products, are transformed into composite powders of nickel sulfide hollow nanospheres/rGO with mixed crystal structures of Ni3S2 and Ni9S8 phases by the sulfidation process under H2S gas. Nickel sulfide/rGO composite powders with the main crystal structure of Ni3S2 are also prepared as comparison samples by the direct sulfidation of nickel acetate-graphene oxide (GO) composite powders obtained by spray-drying. In electrochemical properties, the discharge capacities at the

  14. Micro- and Nano-scale Measurement of the Thermophysical Properties of Polymeric Materials Using Atomic Force Microscopy

    NASA Astrophysics Data System (ADS)

    Dawson, Angela; Rides, Martin; Cuenat, Alexandre; Winkless, Laurie

    2013-05-01

    To realize the benefits and optimize the performance of micro- and nano-structured materials and thin films, designers need to understand and thus be able to characterize their thermal, thermophysical, and thermomechanical properties on appropriate length scales. This paper describes the determination of glass-transition temperatures of polymers on the micro-scale, obtained from contact force-distance curves for poly(methyl methacrylate) and poly(vinyl acetate) measured using an atomic force microscope (AFM). Measurements were made using a standard AFM tip where thin films were heated using a temperature controlled hot stage and by using a scanning thermal microscopy (SThM) probe. The latter was used either with the hot stage or with the SThM probe providing a localized heating source via Joule heating. Differences in the glass-transition temperature measured using the hot stage and Joule heating were apparent and considered to be due to heat transfer effects between the probe, specimen, and surroundings. Gradients of force-distance curves, pull-off and snap-in forces, and adhesion energy were obtained. The results suggest that the onset of changes in the material's mechanical properties at the glass transition was found to be dependent on the mechanical property measured, with pull-off force values changing at lower temperatures than the snap-in force and adhesion energy.

  15. N-Methylmelamines: Synthesis, Characterization, and Physical Properties.

    PubMed

    List, Manuela; Puchinger, Helmut; Gabriel, Herbert; Monkowius, Uwe; Schwarzinger, Clemens

    2016-05-20

    N-Methylmelamines have recently gained importance as valuable compounds for manufacturing modified melamine formaldehyde resins and other polymer building blocks. A great advantage of these polymers is the reduction of the carcinogenic formaldehyde. Selecting the polymerization processes (e.g., substance polymerization, polymerization in solution) and controlling the polymerization reaction and properties of these novel materials requires knowledge of the properties of the individual melamine derivatives used as new building blocks. All possible permutations of N-methylmelamines were prepared, and reaction progress was monitored by GC/MS. 2,4,6-Tris(dimethylamino)-1,3,5-triazine was prepared to complete the series; this is, however, also a possible byproduct in various synthesis routes. The reaction conditions were optimized to obtain high yields of each derivative with the highest possible purity. The substances were characterized by NMR and IR spectroscopy, mass spectrometry, elemental analysis, and single-crystal X-ray diffraction. In addition, physical properties, such as solubility, melting points, and pKb values, were determined. The number of amino-, methylamino-, and dimethylamino groups has a significant effect on these properties. In summary, we found that by increasing the number of amino- and methylamino groups, solubility and pKb increase. With increasing number of amino groups, the compounds tend to form hydrogen bonds, and thus, the melting point shifts to higher temperature ranges where they start to decompose. PMID:27100712

  16. Nuclear Envelopes Properties and Physical Interactions with Nucleoplasm

    NASA Astrophysics Data System (ADS)

    Discher, Dennis; Dahl, Kris; Wilson, Kathy

    2004-03-01

    Given the stresses imposed on a cell and its organelles and the nuclear envelope's important role as a barrier between cytoplasm and nucleoplasm, we sought to measure and model mechanical properties of isolated nuclear envelopes. Xenopus laevis oocyte (XO) nuclei are primarily used since they have been widely studied in many fields as model systems for nuclear structure and function. We manipulate the nuclear envelope by both osmotic swelling and micromanipulation to determine an effective elastic modulus. We show the envelope properties are independent of the effects of the nucleoplasm. Micropipette aspiration of XO nuclei gives an effective elastic modulus of the nuclear envelope of 250 mN/m with similar results obtained from isotropic swelling of XO nuclear envelopes. The results suggest that these nuclear envelopes have relatively homogeneous properties and are highly elastic, sustaining strains of 50-100Square-net simulations and comparisons to polymer network models suggests that XO nuclear envelope physical properties are dominated by the lamin network. If applicable to nuclei in other cells, a "pre-compressed" state envisioned here would allow for significant shear flexibility, especially important for motile cells whose nuclei need to rapidly deform.

  17. Nanoscale thermal probing

    PubMed Central

    Yue, Yanan; Wang, Xinwei

    2012-01-01

    Nanoscale novel devices have raised the demand for nanoscale thermal characterization that is critical for evaluating the device performance and durability. Achieving nanoscale spatial resolution and high accuracy in temperature measurement is very challenging due to the limitation of measurement pathways. In this review, we discuss four methodologies currently developed in nanoscale surface imaging and temperature measurement. To overcome the restriction of the conventional methods, the scanning thermal microscopy technique is widely used. From the perspective of measuring target, the optical feature size method can be applied by using either Raman or fluorescence thermometry. The near-field optical method that measures nanoscale temperature by focusing the optical field to a nano-sized region provides a non-contact and non-destructive way for nanoscale thermal probing. Although the resistance thermometry based on nano-sized thermal sensors is possible for nanoscale thermal probing, significant effort is still needed to reduce the size of the current sensors by using advanced fabrication techniques. At the same time, the development of nanoscale imaging techniques, such as fluorescence imaging, provides a great potential solution to resolve the nanoscale thermal probing problem. PMID:22419968

  18. Study of the physical properties of crystalline rocks in the southeast Voronezh anteclise

    NASA Technical Reports Server (NTRS)

    Dmitriyevskiy, V. S.; Afanasyev, N. S.; Frolov, S. M.

    1985-01-01

    The physical properties of rocks, in the crystalline mass of the Voronezh anteclise, were studied. The study of the physical properties of rocks is important for the improvement of geophysical methods for mapping crystalline rocks in the foundation and exploration of different geological objects which are associated with the crystalline foundation, covered by the sedimentary mantle. It is found that: (1) rocks in the crystalline foundation are very different in physical properties; (2) the physical properties are closely related to their substance composition and genesis; (3) petrographic properties give clues of rock afficiation to certain complexes; and (4) physical and magnetic properties should be examined by petrography, chemical and X-ray analysis.

  19. Ab initio calculations of optical properties of silver clusters: cross-over from molecular to nanoscale behavior

    NASA Astrophysics Data System (ADS)

    Titantah, John T.; Karttunen, Mikko

    2016-05-01

    Electronic and optical properties of silver clusters were calculated using two different ab initio approaches: (1) based on all-electron full-potential linearized-augmented plane-wave method and (2) local basis function pseudopotential approach. Agreement is found between the two methods for small and intermediate sized clusters for which the former method is limited due to its all-electron formulation. The latter, due to non-periodic boundary conditions, is the more natural approach to simulate small clusters. The effect of cluster size is then explored using the local basis function approach. We find that as the cluster size increases, the electronic structure undergoes a transition from molecular behavior to nanoparticle behavior at a cluster size of 140 atoms (diameter ~1.7 nm). Above this cluster size the step-like electronic structure, evident as several features in the imaginary part of the polarizability of all clusters smaller than Ag147, gives way to a dominant plasmon peak localized at wavelengths 350 nm ≤ λ ≤ 600 nm. It is, thus, at this length-scale that the conduction electrons' collective oscillations that are responsible for plasmonic resonances begin to dominate the opto-electronic properties of silver nanoclusters.

  20. Soil physical properties influence "black truffle" fructification in plantations.

    PubMed

    Alonso Ponce, Rafael; Ágreda, Teresa; Águeda, Beatriz; Aldea, Jorge; Martínez-Peña, Fernando; Modrego, María Pilar

    2014-04-01

    Although the important effects of pH and carbonate content of soils on "black truffle" (Tuber melanosporum) production are well known, we poorly understand the influence of soil physical properties. This study focuses on physical soil characteristics that drive successful production of black truffles in plantations. Seventy-eight Quercus ilex ssp. ballota plantations older than 10 years were studied in the province of Teruel (eastern Spain). Soil samples were analyzed for various edaphic characteristics and to locate T. melanosporum ectomycorrhizae. The influence of cultivation practices, climatic features, and soil properties on sporocarp production was assessed using multivariate analyses. Low contents of fine earth and silt and high levels of bulk density, clay content, and water-holding capacity appear to promote fructification. Watering is also highly positive for truffle fructification. We develop and discuss a logistic model to predict the probability of truffle fructification in field sites under consideration for truffle plantation establishment. The balance between water availability and aeration plays a crucial role in achieving success in black truffle plantations. PMID:24487451

  1. Hanford Waste Physical and Rheological Properties: Data and Gaps - 12078

    SciTech Connect

    Kurath, D.E.; Wells, B.E.; Huckaby, J.L.; Mahoney, L.A.; Daniel, R.C.; Burns, C.A.; Tingey, J.M.; Cooley, S.K.

    2012-07-01

    The retrieval, transport, treatment and disposal operations associated with Hanford Tank Wastes involve the handling of a wide range of slurries. Knowledge of the physical and rheological properties of the waste is a key component to the success of the design and implementation of the waste processing facilities. Previous efforts to compile and analyze the physical and rheological properties were updated with new results including information on solids composition and density, particle size distributions, slurry rheology, and particle settling behavior. The primary source of additional data is from a recent series of tests sponsored by the Hanford Waste Treatment and Immobilization Plant (WTP). These tests involved an extensive suite of characterization and bench-scale process testing of 8 waste groups representing approximately 75% of the high-level waste mass expected to be processed through the WTP. Additional information on the morphology of the waste solids was also included. Based on the updated results, a gap analysis to identify gaps in characterization data, analytical methods and data interpretation was completed. (authors)

  2. Hanford Waste Physical and Rheological Properties: Data and Gaps

    SciTech Connect

    Kurath, Dean E.; Wells, Beric E.; Huckaby, James L.; Mahoney, Lenna A.; Daniel, Richard C.; Burns, Carolyn A.; Tingey, Joel M.; Cooley, Scott K.

    2012-03-01

    The retrieval, transport, treatment and disposal operations associated with Hanford Tank Wastes involve the handling of a wide range of slurries. Knowledge of the physical and rheological properties of the waste is a key component to the success of the design and implementation of the waste processing facilities. Previous efforts to compile and analyze the physical and rheological properties were updated with new results including information on solids composition and density, particle size distributions, slurry rheology, and particle settling behavior. The primary source of additional data is from a recent series of tests sponsored by the Hanford Waste Treatment and Immobilization Plant. These tests involved an extensive suite of characterization and bench-scale process testing of 8 waste groups representing approximately 75% of the high-level waste mass expected to be processed through the WTP. Additional information on the morphology of the waste solids was also included. Based on the updated results, a gap analysis to identify gaps in characterization data, analytical methods and data interpretation was completed.

  3. Cesium Eluate Evaporation Solubility and Physical Property Behavior

    SciTech Connect

    Pierce, R.A.

    2003-06-12

    The baseline flowsheet for low activity waste (LAW) in the Hanford River Protection Project (RPP) Waste Treatment Plant (WTP) includes pretreatment of supernatant by removing cesium using ion exchange. When the ion exchange column is loaded, the cesium will be eluted with a 0.5M nitric acid (HNO3) solution to allow the column to be conditioned for re-use. The cesium eluate solution will then be concentrated in a vacuum evaporator to minimize storage volume and recycle HNO3. To prevent the formation of solids during storage of the evaporator bottoms, criteria have been set for limiting the concentration of the evaporator product to 80 percent of saturation at 25 degrees C. Prior work has collected fundamental data for predicting solubility and other physical property measurements. Other ongoing efforts have involved the development of a computer model to predict solubility and physical properties during evaporation. Evaporation experiments were conducted with cesium eluate simulant generated from a pilot scale experiment in the Thermal Fluids Lab (TFL) at the Savannah River Technology Center (SRTC). The data from the experiments will be used to validate the modeling data.

  4. Physical properties of polymorphic yeast prion amyloid fibers.

    PubMed

    Castro, Carlos E; Dong, Jijun; Boyce, Mary C; Lindquist, Susan; Lang, Matthew J

    2011-07-20

    Amyloid fibers play important roles in many human diseases and natural biological processes and have immense potential as novel nanomaterials. We explore the physical properties of polymorphic amyloid fibers formed by yeast prion protein Sup35. Amyloid fibers that conferred distinct prion phenotypes ([PSI(+)]), strong (S) versus weak (W) nonsense suppression, displayed different physical properties. Both S[PSI(+)] and W[PSI(+)] fibers contained structural inhomogeneities, specifically local regions of static curvature in S[PSI(+)] fibers and kinks and self-cross-linking in W[PSI(+)] fibers. Force-extension experiments with optical tweezers revealed persistence lengths of 1.5 μm and 3.3 μm and axial stiffness of 5600 pN and 9100 pN for S[PSI(+)] and W[PSI(+)] fibers, respectively. Thermal fluctuation analysis confirmed the twofold difference in persistence length between S[PSI(+)] and W[PSI(+)] fibers and revealed a torsional stiffness of kinks and cross-links of ~100-200 pN·nm/rad. PMID:21767497

  5. Physical-chemical property based sequence motifs and methods regarding same

    DOEpatents

    Braun, Werner; Mathura, Venkatarajan S.; Schein, Catherine H.

    2008-09-09

    A data analysis system, program, and/or method, e.g., a data mining/data exploration method, using physical-chemical property motifs. For example, a sequence database may be searched for identifying segments thereof having physical-chemical properties similar to the physical-chemical property motifs.

  6. PHYSICAL PROPERTY MEASUREMENTS OF LABORATORY PREPARED SALTSTONE GROUT

    SciTech Connect

    Hansen, E.; Cozzi, A.; Edwards, T.

    2014-05-05

    The Saltstone Production Facility (SPF) built two new Saltstone Disposal Units (SDU), SDU 3 and SDU 5, in 2013. The variable frequency drive (VFD) for the grout transfer hose pump tripped due to high current demand by the motor during the initial radioactive saltstone transfer to SDU 5B on 12/5/2013. This was not observed during clean cap processing on July 5, 2013 to SDU 3A, which is a slightly longer distance from the SPF than is SDU 5B. Saltstone Design Authority (SDA) is evaluating the grout pump performance and capabilities to transfer the grout processed in SPF to SDU 3/5. To assist in this evaluation, grout physical properties are required. At this time, there are no rheological data from the actual SPF so the properties of laboratory prepared samples using simulated salt solution or Tank 50 salt solution will be measured. The physical properties of grout prepared in the laboratory with de-ionized water (DI) and salt solutions were obtained at 0.60 and 0.59 water to premix (W/P) ratios, respectively. The yield stress of the DI grout was greater than any salt grout. The plastic viscosity of the DI grout was lower than all of the salt grouts (including salt grout with admixture). When these physical data were used to determine the pressure drop and fluid horsepower for steady state conditions, the salt grouts without admixture addition required a higher pressure drop and higher fluid horsepower to transport. When 0.00076 g Daratard 17/g premix was added, both the pressure drop and fluid horsepower were below that of the DI grout. Higher concentrations of Daratard 17 further reduced the pressure drop and fluid horsepower. The uncertainty in the single point Bingham Plastic parameters is + 4% of the reported values and is the bounding uncertainty. Two different mechanical agitator mixing protocols were followed for the simulant salt grout, one having a total mixing time of three minutes and the other having a time of 10 minutes. The Bingham Plastic parameters

  7. Quasar Spectral Energy Distributions As A Function Of Physical Property

    NASA Astrophysics Data System (ADS)

    Townsend, Shonda; Ganguly, R.; Stark, M. A.; Derseweh, J. A.; Richmond, J. M.

    2012-05-01

    Galaxy evolution models have shown that quasars are a crucial ingredient in the evolution of massive galaxies. Outflows play a key role in the story of quasars and their host galaxies, by helping regulate the accretion process, the star-formation rate and mass of the host galaxy (i.e., feedback). The prescription for modeling outflows as a contributor to feedback requires knowledge of the outflow velocity, geometry, and column density. In particular, we need to understand how these depend on physical parameters and how much is determined stochastically (and with what distribution). In turn, models of outflows have shown particular sensitivity to the shape of the spectral energy distribution (SED), depending on the UV luminosity to transfer momentum to the gas, the X-ray luminosity to regulate how efficiently that transfer can be, etc. To investigate how SED changes with physical properties, we follow up on Richards et al. (2006), who constructed SEDs with varying luminosity. Here, we construct SEDs as a function of redshift, and physical property (black hole mass, bolometric luminosity, Eddington ratio) for volume limited samples drawn from the Sloan Digital Sky Survey, with photometry supplemented from 2MASS, WISE, GALEX, ROSAT, and Chandra. To estimate black hole masses, we adopt the scaling relations from Greene & Ho (2005) based on the H-alpha emission line FWHM. This requires redshifts less than 0.4. To construct volume-limited subsamples, we begin by adopting g=19.8 as a nominal limiting magnitude over which we are guaranteed to detect z<0.4 quasars. At redshift 0.4, we are complete down to Mg=-21.8, which yields 3300 objects from Data Release 7. At z=0.1, we are complete down to Mg=-18.5. This material is based upon work supported by the National Aeronautics and Space Administration under Grant No. 09-ADP09-0016 issued through the Astrophysics Data Analysis Program.

  8. Physical and functional properties of arrowroot starch extrudates.

    PubMed

    Jyothi, A N; Sheriff, J T; Sajeev, M S

    2009-03-01

    Arrowroot starch, a commercially underexploited tuber starch but having potential digestive and medicinal properties, has been subjected to extrusion cooking using a single screw food extruder. Different levels of feed moisture (12%, 14%, and 16%) and extrusion temperatures (140, 150, 160, 170, 180, and 190 degrees C) were used for extrusion. The physical properties--bulk density, true density, porosity, and expansion ratio; functional properties such as water absorption index, water solubility index, oil absorption index, pasting, rheological, and textural properties; and in vitro enzyme digestibility of the extrudates were determined. The expansion ratio of the extrudates ranged from 3.22 to 6.09. The water absorption index (6.52 to 8.85 g gel/g dry sample), water solubility index (15.92% to 41.31%), and oil absorption index (0.50 to 1.70 g/g) were higher for the extrudates in comparison to native starch (1.81 g gel/g dry sample, 1.16% and 0.60 g/g, respectively). The rheological properties, storage modulus, and loss modulus of the gelatinized powdered extrudates were significantly lower (P < 0.05) and these behaved like solutions rather than a paste or a gel. Hardness and toughness were more for the samples extruded at higher feed moisture and lower extrusion temperature, whereas snap force and energy were higher at lower feed moisture and temperature. There was a significant decrease in the percentage digestibility of arrowroot starch (30.07% after 30 min of incubation with the enzyme) after extrusion (25.27% to 30.56%). Extrusion cooking of arrowroot starch resulted in products with very good expansion, color, and lower digestibility, which can be exploited for its potential use as a snack food. PMID:19323747

  9. Functionalised nanoscale coatings using layer-by-layer assembly for imparting antibacterial properties to polylactide-co-glycolide surfaces.

    PubMed

    Gentile, Piergiorgio; Frongia, Maria E; Cardellach, Mar; Miller, Cheryl A; Stafford, Graham P; Leggett, Graham J; Hatton, Paul V

    2015-07-01

    In order to achieve high local biological activity and reduce the risk of side effects of antibiotics in the treatment of periodontal and bone infections, a localised and temporally controlled delivery system is desirable. The aim of this research was to develop a functionalised and resorbable surface to contact soft tissues to improve the antibacterial behaviour during the first week after its implantation in the treatment of periodontal and bone infections. Solvent-cast poly(d,l-lactide-co-glycolide acid) (PLGA) films were aminolysed and then modified by Layer-by-Layer technique to obtain a nano-layered coating using poly(sodium4-styrenesulfonate) (PSS) and poly(allylamine hydrochloride) (PAH) as polyelectrolytes. The water-soluble antibiotic, metronidazole (MET), was incorporated from the ninth layer. Infrared spectroscopy showed that the PSS and PAH absorption bands increased with the layer number. The contact angle values had a regular alternate behaviour from the ninth layer. X-ray Photoelectron Spectroscopy evidenced two distinct peaks, N1s and S2p, indicating PAH and PSS had been introduced. Atomic Force Microscopy showed the presence of polyelectrolytes on the surface with a measured roughness about 10nm after 20 layers' deposition. The drug release was monitored by Ultraviolet-visible spectroscopy showing 80% loaded-drug delivery in 14 days. Finally, the biocompatibility was evaluated in vitro with L929 mouse fibroblasts and the antibacterial properties were demonstrated successfully against the keystone periodontal bacteria Porphyromonas gingivalis, which has an influence on implant failure, without compromising in vitro biocompatibility. In this study, PLGA was successfully modified to obtain a localised and temporally controlled drug delivery system, demonstrating the potential value of LbL as a coating technology for the manufacture of medical devices with advanced functional properties. PMID:25871538

  10. Nanoscale Tailoring of the Polarization Properties of Dilute-Nitride Semiconductors via H-Assisted Strain Engineering

    NASA Astrophysics Data System (ADS)

    Felici, Marco; Birindelli, Simone; Trotta, Rinaldo; Francardi, Marco; Gerardino, Annamaria; Notargiacomo, Andrea; Rubini, Silvia; Martelli, Faustino; Capizzi, Mario; Polimeni, Antonio

    2014-12-01

    In dilute-nitride semiconductors, the possibility to selectively passivate N atoms by spatially controlled hydrogen irradiation allows for tailoring the effective N concentration of the host—and, therefore, its electronic and structural properties—with a precision of a few nanometers. In the present work, this technique is applied to the realization of ordered arrays of GaAs1 -xNx/GaAs1 -xNx∶H wires oriented at different angles with respect to the crystallographic axes of the material. The creation of a strongly anisotropic strain field in the plane of the sample, due to the lattice expansion of the fully hydrogenated regions surrounding the GaAs1 -xNx wires, is directly responsible for the peculiar polarization properties observed for the wire emission. Temperature-dependent polarization-resolved microphotoluminescence measurements, indeed, reveal a nontrivial dependence of the degree of linear polarization on the wire orientation, with maxima for wires parallel to the [110] and [1 1 ¯ 0 ] directions and a pronounced minimum for wires oriented along the [100] axis. In addition, the polarization direction is found to be precisely perpendicular to the wire when the latter is oriented along high-symmetry crystal directions, whereas significant deviations from a perfect orthogonality are measured for all other wire orientations. These findings, which are well reproduced by a theoretical model based on finite-element calculations of the strain profile of our GaAs1 -xNx/GaAs1 -xNx∶H heterostructures, demonstrate our ability to control the polarization properties of dilute-nitride micro- and nanostructures via H-assisted strain engineering. This additional degree of freedom may prove very useful in the design and optimization of innovative photonic structures relying on the integration of dilute-nitride-based light emitters with photonic crystal microcavities.

  11. Aerosols physical properties at Hada Al Sham, western Saudi Arabia

    NASA Astrophysics Data System (ADS)

    Lihavainen, H.; Alghamdi, M. A.; Hyvärinen, A.-P.; Hussein, T.; Aaltonen, V.; Abdelmaksoud, A. S.; Al-Jeelani, H.; Almazroui, M.; Almehmadi, F. M.; Al Zawad, F. M.; Hakala, J.; Khoder, M.; Neitola, K.; Petäjä, T.; Shabbaj, I. I.; Hämeri, K.

    2016-06-01

    This is the first time to clearly derive the comprehensive physical properties of aerosols at a rural background area in Saudi Arabia. Aerosol measurements station was established at a rural background area in the Western Saudi Arabia to study the aerosol properties. This study gives overview of the aerosol physical properties (PM10, PM2.5, black carbon and total number concentration) over the measurement period from November 2012 to February 2015. The average PM10 and PM2.5 concentrations were 95 ± 78 μg m-3 (mean ± STD, at ambient conditions) and 33 ± 68 μg m-3 (at ambient conditions), respectively. As expected PM10 concentration was dominated by coarse mode particles (PM10-PM2.5), most probably desert dust. Especially from February to June the coarse mode concentrations were high because of dust storm season. Aerosol mass concentrations had clear diurnal cycle. Lower values were observed around noon. This behavior is caused by wind direction and speed, during night time very calm easterly winds are dominating whereas during daytime the stronger westerly winds are dominating (sea breeze). During the day time the boundary layer is evolving, causing enhanced mixing and dilution leading to lower concentration. PM10 and PM2.5 concentrations were comparable to values measured at close by city of Jeddah. Black carbon concentration was about 2% and 6% of PM10 and PM2.5 mass, respectively. Total number concentration was dominated by frequent new particle formation and particle growth events. The typical diurnal cycle in particle total number concentration was clearly different from PM10 and PM2.5.

  12. Planetary Defense and the High Temperture Physical Properties of Meteorites.

    NASA Astrophysics Data System (ADS)

    Ostrowski, D. R.; Sears, D. W. G.; Bryson, K.

    2015-12-01

    The Ames Meteorite Characterization Laboratory is examining the physical proprerties of a diverse selection of meteorites. Each meteorite will be processed by the full suite of observations and measurements: petrographic/microscopic studies, density, porosity, albedo, shock effects, thermal conductivity, heat capacity, emissivity, and acoustic velocity. Of these measurments, density and porosity are the most studied to date (Macke, 2010; Britt and Consolmagno, 2003). The thermal properties of meteorites are less well understood. Thermal conductivity, heat capacity, and thermal emissivity are important data for a number of applications but especially to understanding the behavior of a meteor as it passes through the atmosphere. Opeil et al. (2010) have shown that meteorites have a thermal conductivities lower than the pure minerals they are composed of by a factor of 3 to 10, with the values coming to a roughly constant number from 150 to 300 K. Calculated conductivity numbers from Yomogida and Matsui (1983) show the H chondrites have the higest conductivity in the range of 3.8 W/m*K at 200 K and then slowly decreases to 3.2 W/m*K at 400 K. Whereas they show the LL chondrites do not reach 1 W/m*K over the temperature range 100 to 400 K. While there have been several high temperature spectroscopic studies of meteorites, to date all experimental data for the physical properties of meteorites were obtained at temperatures below 400 K, since previous studies were made in attempts to understand the formation and evolution of asteroids. Our laboratory will focus on understanding the thermal properties of materials at temperatures above 300 K and, where possible, up to atmospheric entry temperatures. Work on pure minerals has shown that thermal conductivity decreases as temperatures exceed 300 K but it is unknown whether this holds true for meteorites. We will describe our laboratory and procedures, and present some preliminary data, at the meeting.

  13. First evidence on phloem transport of nanoscale calcium oxide in groundnut using solution culture technique

    NASA Astrophysics Data System (ADS)

    Deepa, Manchala; Sudhakar, Palagiri; Nagamadhuri, Kandula Venkata; Balakrishna Reddy, Kota; Giridhara Krishna, Thimmavajjula; Prasad, Tollamadugu Naga Venkata Krishna Vara

    2015-06-01

    Nanoscale materials, whose size typically falls below 100 nm, exhibit novel chemical, physical and biological properties which are different from their bulk counterparts. In the present investigation, we demonstrated that nanoscale calcium oxide particles (n-CaO) could transport through phloem tissue of groundnut unlike the corresponding bulk materials. n-CaO particles are prepared using sol-gel method. The size of the as prepared n-CaO measured (69.9 nm) using transmission electron microscopic technique (TEM). Results of the hydroponics experiment using solution culture technique revealed that foliar application of n-CaO at different concentrations (10, 50, 100, 500, 1,000 ppm) on groundnut plants confirmed the entry of calcium into leaves and stems through phloem compared to bulk source of calcium sprayed (CaO and CaNO3). After spraying of n-CaO, calcium content in roots, shoots and leaves significantly increased. Based on visual scoring of calcium deficiency correction and calcium content in plant parts, we may establish the fact that nanoscale calcium oxide particles (size 69.9 nm) could move through phloem tissue in groundnut. This is the first report on phloem transport of nanoscale calcium oxide particles in plants and this result points to the use of nanoscale calcium oxide particles as calcium source to the plants through foliar application, agricultural crops in particular, as bulk calcium application through foliar nutrition is restricted due to its non-mobility in phloem.

  14. Computational Studies of Physical Properties of Boron Carbide

    SciTech Connect

    Lizhi Ouyang

    2011-09-30

    The overall goal is to provide valuable insight in to the mechanisms and processes that could lead to better engineering the widely used boron carbide which could play an important role in current plight towards greener energy. Carbon distribution in boron carbide, which has been difficult to retrieve from experimental methods, is critical to our understanding of its structure-properties relation. For modeling disorders in boron carbide, we implemented a first principles method based on supercell approach within our G(P,T) package. The supercell approach was applied to boron carbide to determine its carbon distribution. Our results reveal that carbon prefers to occupy the end sites of the 3-atom chain in boron carbide and further carbon atoms will distribute mainly on the equatorial sites with a small percentage on the 3-atom chains and the apex sites. Supercell approach was also applied to study mechanical properties of boron carbide under uniaxial load. We found that uniaxial load can lead to amorphization. Other physical properties of boron carbide were calculated using the G(P,T) package.

  15. Relationships between physical properties and sequence in silkworm silks

    PubMed Central

    Malay, Ali D.; Sato, Ryota; Yazawa, Kenjiro; Watanabe, Hiroe; Ifuku, Nao; Masunaga, Hiroyasu; Hikima, Takaaki; Guan, Juan; Mandal, Biman B.; Damrongsakkul, Siriporn; Numata, Keiji

    2016-01-01

    Silk has attracted widespread attention due to its superlative material properties and promising applications. However, the determinants behind the variations in material properties among different types of silk are not well understood. We analysed the physical properties of silk samples from a variety of silkmoth cocoons, including domesticated Bombyx mori varieties and several species from Saturniidae. Tensile deformation tests, thermal analyses, and investigations on crystalline structure and orientation of the fibres were performed. The results showed that saturniid silks produce more highly-defined structural transitions compared to B. mori, as seen in the yielding and strain hardening events during tensile deformation and in the changes observed during thermal analyses. These observations were analysed in terms of the constituent fibroin sequences, which in B. mori are predicted to produce heterogeneous structures, whereas the strictly modular repeats of the saturniid sequences are hypothesized to produce structures that respond in a concerted manner. Within saturniid fibroins, thermal stability was found to correlate with the abundance of poly-alanine residues, whereas differences in fibre extensibility can be related to varying ratios of GGX motifs versus bulky hydrophobic residues in the amorphous phase. PMID:27279149

  16. Gamma irradiation influence on physical properties of milk proteins

    NASA Astrophysics Data System (ADS)

    Cieśla, K.; Salmieri, S.; Lacroix, M.; Tien, C. Le

    2004-09-01

    Gamma irradiation was found to be an effective method for the improvement of both barrier and mechanical properties of the edible films and coatings based on calcium and sodium caseinates alone or combined with some globular proteins. Our current studies concern gamma irradiation influence on the physical properties of calcium caseinate-whey protein isolate-glycerol (1:1:1) solutions and gels, used for films preparation. Irradiation of solutions was carried out with Co-60 gamma rays applying 0 and 32 kGy dose. The increase in viscosity of solutions was found after irradiation connected to induced crosslinking. Lower viscosity values were detected, however, after heating of the solutions irradiated with a 32 kGy dose than after heating of the non-irradiated ones regarding differences in the structure of gels and resulting in different temperature-viscosity curves that were recorded for the irradiated and the non-irradiated samples during heating and cooling. Creation of less stiff but better ordered gels after irradiation arises probably from reorganisation of aperiodic helical phase and β-sheets, in particular from increase of β-strands, detected by FTIR. Films obtained from these gels are characterised by improved barrier properties and mechanical resistance and are more rigid than those prepared from the non-irradiated gels. The route of gel creation was investigated for the control and the irradiated samples during heating and the subsequent cooling.

  17. Relationships between physical properties and sequence in silkworm silks.

    PubMed

    Malay, Ali D; Sato, Ryota; Yazawa, Kenjiro; Watanabe, Hiroe; Ifuku, Nao; Masunaga, Hiroyasu; Hikima, Takaaki; Guan, Juan; Mandal, Biman B; Damrongsakkul, Siriporn; Numata, Keiji

    2016-01-01

    Silk has attracted widespread attention due to its superlative material properties and promising applications. However, the determinants behind the variations in material properties among different types of silk are not well understood. We analysed the physical properties of silk samples from a variety of silkmoth cocoons, including domesticated Bombyx mori varieties and several species from Saturniidae. Tensile deformation tests, thermal analyses, and investigations on crystalline structure and orientation of the fibres were performed. The results showed that saturniid silks produce more highly-defined structural transitions compared to B. mori, as seen in the yielding and strain hardening events during tensile deformation and in the changes observed during thermal analyses. These observations were analysed in terms of the constituent fibroin sequences, which in B. mori are predicted to produce heterogeneous structures, whereas the strictly modular repeats of the saturniid sequences are hypothesized to produce structures that respond in a concerted manner. Within saturniid fibroins, thermal stability was found to correlate with the abundance of poly-alanine residues, whereas differences in fibre extensibility can be related to varying ratios of GGX motifs versus bulky hydrophobic residues in the amorphous phase. PMID:27279149

  18. Relationships between physical properties and sequence in silkworm silks

    NASA Astrophysics Data System (ADS)

    Malay, Ali D.; Sato, Ryota; Yazawa, Kenjiro; Watanabe, Hiroe; Ifuku, Nao; Masunaga, Hiroyasu; Hikima, Takaaki; Guan, Juan; Mandal, Biman B.; Damrongsakkul, Siriporn; Numata, Keiji

    2016-06-01

    Silk has attracted widespread attention due to its superlative material properties and promising applications. However, the determinants behind the variations in material properties among different types of silk are not well understood. We analysed the physical properties of silk samples from a variety of silkmoth cocoons, including domesticated Bombyx mori varieties and several species from Saturniidae. Tensile deformation tests, thermal analyses, and investigations on crystalline structure and orientation of the fibres were performed. The results showed that saturniid silks produce more highly-defined structural transitions compared to B. mori, as seen in the yielding and strain hardening events during tensile deformation and in the changes observed during thermal analyses. These observations were analysed in terms of the constituent fibroin sequences, which in B. mori are predicted to produce heterogeneous structures, whereas the strictly modular repeats of the saturniid sequences are hypothesized to produce structures that respond in a concerted manner. Within saturniid fibroins, thermal stability was found to correlate with the abundance of poly-alanine residues, whereas differences in fibre extensibility can be related to varying ratios of GGX motifs versus bulky hydrophobic residues in the amorphous phase.

  19. Mark Correlations: Relating Physical Properties to Spatial Distributions

    NASA Astrophysics Data System (ADS)

    Beisbart, Claus; Kerscher, Martin; Mecke, Klaus

    Mark correlations provide a systematic approach to look at objects both distributed in space and bearing intrinsic information, for instance on physical properties. The interplay of the objects' properties (marks) with the spatial clustering is of vivid interest for many applications; are, e.g., galaxies with high luminosities more strongly clustered than dim ones? Do neighbored pores in a sandstone have similar sizes? How does the shape of impact craters on a planet dependon the geological surface properties? In this article, we give an introduction into the appropriate mathematical framework to deal with such questions, i.e. the theory of marked point processes. After having clarified the notion of segregation effects, we define universal test quantities applicable to realizations of a marked point processes. We show their power using concrete data sets in analyzing the luminosity-dependence of the galaxy clustering, the alignment of dark matter halos in gravitational N-body simulations, the morphology- and diameter-dependence of the Martian crater distribution and the size correlations of pores in sandstone. In order to understand our data in more detail, we discuss the Boolean depletion model, the random field model and the Cox random field model. The first model describes depletion effects in the distribution of Martian craters and pores in sandstone, whereas the last one accounts at least qualitatively for the observed luminosity-dependence of the galaxy clustering.

  20. Some physical and mechanical properties of roasted Zerun wheat.

    PubMed

    Işıklı, Nursel Develi; Senol, Belma; Coksöyler, Nafi

    2014-09-01

    Some physical and mechanical properties of roasted Zerun wheat were investigated in the moisture range from 8.80 % to 23.40 % wet basis. Mechanical properties were evaluated by examining the effect of moisture content upon the grain rupture force, energy and Weibull parameters. Length, width, thickness, porosity and angle of repose increased nonlinearly from 6.09 to 6.36 mm; 4.17 to 4.18 mm; 2.66 to 2.78 mm; 37.71 % to 39.09 % and 33.02° to 37.90°, respectively when moisture content increased. The Weibull distribution fits the data for rupture force and energy. The Weibull modulus and scale parameter for rupture force varied between 3.88 and 6.20; 26.61 and 44.24N, respectively. The Weibull modulus for energy increased from 2.15 to 3.24 with increased in moisture content. Measured mechanical properties of grains showed that the brittleness and fragile structure of the roasted grain gradually lost its characteristic crispiness and become soft and ductile above 13.78 % moisture content. PMID:25190855

  1. Structure and physical properties of Hydrogrossular mineral series

    NASA Astrophysics Data System (ADS)

    Adhikari, Puja

    The mineral hydrogrossular series (Ca3Al2(SiO 4)3-x(OH)4x; 0 ≤ x ≤ 3) are important water bearing minerals found in the upper and lower part of the Earth's mantle. They are vital to the planet's hydrosphere under different hydrothermal conditions. The composition and structure of this mineral series are important in geoscience and share many commonalities with cement and clay materials. Other than the end members of the series x = 0 (grossular) and x = 3 (katoite) which have a cubic garnet structure, the structure of the series is totally unknown. We used large-scale ab initio modeling to investigate the structures and properties for hydrogrossular series for x = 0, 0.5, 1, 1.5, 2, 2.5, 3. Results indicate that for x > 0 and x < 3, the structures are tetragonal. This shows that there is structural change related to the lowering of overall symmetry associated with the composition of SiO4 tetrahedra and AlO6 octahedra. Total Bond order also explains the reason behind the change in the compressibility of the series. The electronic structure, mechanical and optical properties of the hydrogrossular series are calculated and the results for grossular and katoite are in good agreement with the available experimental data. The x--dependence of these physical properties for the series supports the notion of the aforementioned structural transition from cubic to tetragonal.

  2. Photoinduced energy transfer across non-covalent bonds in the nanoscale: cyclodextrin hosts with enhanced luminescent properties for guest communication.

    PubMed

    Faiz, Jonathan A; Kyllonen, Lasse E P; Contreras-Carballada, Pablo; Williams, René M; De Cola, Luisa; Pikramenou, Zoe

    2009-05-28

    Two photoactive cyclodextrin hosts have been prepared and studied in participation on photophysical processes, one with a ruthenium tris(bipyridyl) core which forms a trimeric host and the other with an appended anthracene unit. An acetylide functionalized bipyridyl cyclodextrin, , was prepared by palladium coupling of mono-6-propargyl permethylated beta-CD and 4-bromo-2,2'-bipyridine. The ruthenium complex, [Ru(3)]Cl(2), shows luminescence from the (3)MLCT centered at 650 nm with a quantum yield of 0.044 and a lifetime at room temperature of 1.1 micros in aerated aqueous solution. The enhanced luminescence properties have been attributed to extra delocalisation afforded by the three propargyl units appended to the complex and the stabilization of the MLCT state. An anthracene functionalised cyclodextrin was prepared from mono-6-O-p-toluenesulfonyl permethylated beta-cyclodextrin and 9-anthracene methanol. It shows fluorescence at room temperature with a maximum at 400 nm with a lifetime of 7 ns. Transient absorption spectroscopy has been used to elucidate the excited state properties of [Ru(3)]Cl(2) and hosts. A broad band centered around 600 nm in the [Ru(3)]Cl(2) transient spectrum corresponds to the absorption of the pi-radical anion of the ethynyl fragment of ligand and in a signal at 595 nm was observed, corresponding to the absorption of the anthracene excited singlet state. We used a bisadamantyl guest to assemble the two hosts and studied the energy transfer from the ruthenium core to the anthracene unit by steady state emission spectroscopy. The photoinduced energy transfer process in assemblies of host with ruthenium or osmium metalloguests, [Ru(biptpy)(tpy)](NO(3))(2) and [Os(biptpy)(tpy)](NO(3))(2), was studied by femtosecond transient spectroscopy and steady state emission spectroscopy. The singlet state of the anthracene pendant unit acted as a donor to the MLCT of the Ru(II) or Os(II) metalloguests. An energy transfer rate from the singlet

  3. Biosafe Nanoscale Pharmaceutical Adjuvant Materials

    PubMed Central

    Jin, Shubin; Li, Shengliang; Wang, Chongxi; Liu, Juan; Yang, Xiaolong; Wang, Paul C.; Zhang, Xin; Liang, Xing-Jie

    2014-01-01

    Thanks to developments in the field of nanotechnology over the past decades, more and more biosafe nanoscale materials have become available for use as pharmaceutical adjuvants in medical research. Nanomaterials possess unique properties which could be employed to develop drug carriers with longer circulation time, higher loading capacity, better stability in physiological conditions, controlled drug release, and targeted drug delivery. In this review article, we will review recent progress in the application of representative organic, inorganic and hybrid biosafe nanoscale materials in pharmaceutical research, especially focusing on nanomaterial-based novel drug delivery systems. In addition, we briefly discuss the advantages and notable functions that make these nanomaterials suitable for the design of new medicines; the biosafety of each material discussed in this article is also highlighted to provide a comprehensive understanding of their adjuvant attributes. PMID:25429253

  4. Correlating bulk properties and nanoscale rearrangement during UV-initiated gelation of hybrid nanoparticle/ block copolymer systems

    NASA Astrophysics Data System (ADS)

    Juggernauth, K. Anne; Seifert, Soenke; Love, Brian

    2013-03-01

    We use rheology and Small Angle X-Ray Scattering (SAXS) to investigate UV initiated gel formation in aqueous dispersions of clay nanoparticles in the presence of poly(ethyleneoxide-b-propyleneoxide-b-ethyleneoxide) block copolymer surfactants (Pluronics®) and small amounts of a photoacid generator (PAG). This material system demonstrates stable liquid-like behavior in the absence of UV but undergoes bulk gelation upon UV exposure. Rheology was used to monitor the bulk properties of a series of samples undergoing UV exposure and confirm bulk gel formation. We further probe nanoparticle rearrangement using time resolved synchrotron SAXS with simultaneous UV exposure. Time dependent SAXS indicate an absence of long range order and crystallinity while changes in the scattering profile are related to short range interparticle interactions leading to a stable or arrested structure. Finally, we compare the time scales for structural rearrangement of nanoparticles with the bulk gelation behavior. Our results show that the kinetics for local structural changes between particles and bulk gelation from UV exposure are strongly correlated.

  5. Almandine: Crystal Chemistry, Defects, Inclusions and Physical Properties

    NASA Astrophysics Data System (ADS)

    Geiger, C. A.; Brearley, A. J.; Dachs, E.; Tippelt, G.

    2013-12-01

    Almandine-rich garnet is important in various metamorphic rocks of Earth's crust and garnet in the upper mantle contains a substantial almandine component (Fe3Al2Si3O12). In order to better understand almandine's chemical and physical properties, crystals were synthesized at high pressures and temperatures under different fO2 conditions with different starting materials. The synthetic products were carefully characterized and the role of defects and solid inclusions were given special attention. Almandine in both polycrystalline and in single-crystal form was obtained in the synthesis experiments. Hydrothermal experiments yielded almandine single crystals from roughly 5 microns in size up to approximately one millimeter and show varying physical properties. Fine-grained polycrystalline almandine in the form of compact pellets was obtained from water-free syntheses made in graphite capsules. The crystals were investigated using X-ray powder diffraction, electron microprobe and TEM analysis, and using 57Fe Mössbauer and IR single-crystal spectroscopy. BSE photos on different polycrystalline almandines, synthesized without water, show a variety of fine inclusions and unreacted starting material. TEM results show certain nanosized, 100 nm to less then 10 nm, magnetite inclusions in some synthetic almandines, similar to those observed in natural garnet crystals. A room temperature FTIR single-crystal spectrum of a hydrothermally grown almandine shows two broad OH stretching bands at 3613 cm-1 and approximately 3490 cm-1, both of which split into more bands at 77 K. 57Fe Mössbauer measurements show small but various amounts of Fe3+ in octahedral coordination for many synthetic almandines and whose concentration depends on the synthesis experiment. Various possible local defects in almandine are analyzed using Kröger-Vink notation. The origin of tiny, minor included phases that have been observed in synthetic as well as in natural crystals may be related to defect

  6. Nanoscale {LnIII(24)ZnII(6)} Triangular Metalloring with Magnetic Refrigerant, Slow Magnetic Relaxation, and Fluorescent Properties.

    PubMed

    Zhang, Li; Zhao, Lang; Zhang, Peng; Wang, Chao; Yuan, Sen-Wen; Tang, Jinkui

    2015-12-01

    The self-assembly of Ln(ClO4)3 · 6H2O and Zn(OAc)2 · 2H2O with pyrazine-2-carboxylic acid (HL) results in the formation of three novel nanosized {LnIII(24)ZnII(6)} triangular metallorings, [Gd24Zn6L24(OAc)22(μ3-OH)30(H2O)14](ClO4)7(OAc) · 2CH3OH · 26H2O (1), [Tb24Zn6L24(OAc)22(μ3-OH)30(CH3O)2(CH3OH)2(H2O)10](ClO4)5(OH) · 6CH3OH · 12H2O (2), and (H3O)[Dy24Zn6L24(OAc)22(μ3-OH)30(H2O)14](ClO4)7(OAc)2 · 4CH3OH · 22H2O (3), having the largest nuclearity among any known Ln/Zn clusters. Magnetic and luminescent studies reveal the special prowess for each lanthanide complex. Magnetic studies reveal that 1 exhibits a significant cryogenic magnetocaloric effect with a maximum -ΔSm (isothermal magnetic entropy change) value of 30.0 J kg(-1) K(-1) at 2.5 K and 7 T and that a slow magnetization relaxation is observed for the dysprosium analogue. In addition, the solid-state photophysical properties of 2 display strong characteristic Tb(III) photoluminescent emission in the visible region, suggesting that Tb(III)-based luminescence is sensitized by the effective energy transfer from the ligand HL to the metal centers. PMID:26600284

  7. Modeling of surface roughness: application to physical properties of paper

    NASA Astrophysics Data System (ADS)

    Bloch, Jean-Francis; Butel, Marc

    2000-09-01

    Papermaking process consists in a succession of unit operations having for main objective the expression of water out of the wet paper pad. The three main stages are successively, the forming section, the press section and finally the drying section. Furthermore, another operation (calendering) may be used to improve the surface smoothness. Forming, pressing and drying are not on the scope of this paper, but the influence of formation and calendering on surface roughness is analyzed. The main objective is to characterize the materials and specially its superficial structure. The proposed model is described in order to analyze this topographical aspect. Some experimental results are presented in order to illustrate the interest of this method to better understand physical properties. This work is therefore dedicated to the description of the proposed model: the studied surface is measured at a microscopic scale using for example, a classical stylus profilometry method. Then the obtained surface is transformed using a conformal mapping that retains the surface orientations. Due to the anisotropy of the fiber distribution in the plane of the sheet, the resulting surface is often not isotropic. Hence, the micro facets that identify the interfaces between pores and solid (fibers in the studied case) at the micro level are transformed into a macroscopic equivalent structure. Furthermore, an ellipsoid may be fit to the experimental data in order to obtain a simple model. The ellipticities are proved to be linked for paper to both fiber orientation (through other optical methods) and roughness. These parameters (ellipticities) are shown to be very significant for different end-use properties. Indeed, they shown to be correlated to printing or optical properties, such as gloss for example. We present in a first part the method to obtain a macroscopic description from physical microscopic measurements. Then measurements carried on different paper samples, using a classical

  8. Physical and optical properties of lead doped tellurite glasses

    NASA Astrophysics Data System (ADS)

    Riyatun; Rahmasari, Lita; Marzuki, Ahmad

    2016-02-01

    Physical and optical properties of lead telluride (Pb:TZBN) glasses with composition 55TeO2-(41-x)ZnO-2Bi2O3-2Na2O-xPbO where x = 1.0, 1.5, 2.0, 2.5% mol are presented. UV-VIS-NIR spectra of the glasses in the range of 300 - 800 nm along with their densities and refractive indices at 746 nm were recorded at room temperature. The optical bandgap energy (Eg) has been calculated from the fitting of Tauc plot. On the basis of these results we found that with the increase of Pb2+ content, their refractive indices are increased while their optical bandgaps are decreased. From this experiment, no distinct relationship between the Pb2+ content variation and the electronic polarizability (αO2-) as well as their optical basicity values (A) were observed.

  9. Some physical properties of ginkgo nuts and kernels

    NASA Astrophysics Data System (ADS)

    Ch'ng, P. E.; Abdullah, M. H. R. O.; Mathai, E. J.; Yunus, N. A.

    2013-12-01

    Some data of the physical properties of ginkgo nuts at a moisture content of 45.53% (±2.07) (wet basis) and of their kernels at 60.13% (± 2.00) (wet basis) are presented in this paper. It consists of the estimation of the mean length, width, thickness, the geometric mean diameter, sphericity, aspect ratio, unit mass, surface area, volume, true density, bulk density, and porosity measures. The coefficient of static friction for nuts and kernels was determined by using plywood, glass, rubber, and galvanized steel sheet. The data are essential in the field of food engineering especially dealing with design and development of machines, and equipment for processing and handling agriculture products.

  10. Physical properties of wild mango fruit and nut

    NASA Astrophysics Data System (ADS)

    Ehiem, J. C.; Simonyan, K. J.

    2012-02-01

    Physical properties of two wild mango varieties were studied at 81.9 and 24.5% moisture (w.b.) for the fruits and nuts, respectively. The shape and size of the fruit are the same while that of nuts differs at P = 0.05. The mass, density and bulk density of the fruits are statistically different at P = 0.05 but the volume is the same. The shape and size, volume and bulk density of the nuts are statistically the same at P = 0.05. The nuts of both varieties are also the same at P = 0.05 in terms of mass and density. The packing factor for both fruits and nut of the two varieties are the same at 0.95. The relevant data obtained for the two varieties would be useful for design and development of machines and equipment for processing and handling operations.

  11. Struvite-based fertilizer and its physical and chemical properties.

    PubMed

    Latifian, Maryam; Liu, Jing; Mattiasson, Bo

    2012-12-01

    This study describes a method to formulate struvite fine powder into pellets that are easy to spread on agricultural land. To evaluate the quality of produced pellets, some chemical and physical properties commonly measured for fertilizers were tested. The findings indicated that the salt index and heavy metal content ofstruvite pellets were significantly lower than those of commercial NPK fertilizers. In addition, the percentage of nutrient released from struvite pellets after 105 days was in the range of 9.6-23.2, 8.4-26.7 and 11.3-32.6% for nitrogen, phosphorous and magnesium, respectively, which is considerably lower than that of commercial NPK fertilizer. Among different formulations between struvite crystals and binders, starch and bentonite were the most efficient in agglomerating struvite powder, leading to an increase in the crush strength to over the recommended limit of >2.5 kgf for fertilizer hardness. PMID:23437670

  12. Correlation between network mechanical properties and physical properties in polyester-urethane coatings

    SciTech Connect

    Scanlan, J.C.; Webster, D.C.; Crain, A.L.

    1995-12-31

    An experimental design to study the effect of polyester formulation on properties of polyurethane coatings was conducted. The five design variables studied were number average molecular weight, average hydroxyl functionality, and the composition of the acid functional monomers (adipic acid, isophthalic acid, and 1,4-cyclohexanedicarboxylic acid). The polyesters were crosslinked with a multifunctional isocyanate to form polyurethane coating films. Coatings were analyzed by traditional physical methods as well as by dynamic mechanical thermal analysis (DMTA) and differential scanning calorimetry (DSC). By comparing the crosslink density (XLD) of the coatings and the glass transition temperature (Tg) of the coatings with the coatings physical properties and the design variables, we can resolve the effect of Tg and XLD on the hardness and flexibility of the coatings.

  13. Tuning the physical properties in strontium iridate heterostructures

    NASA Astrophysics Data System (ADS)

    Nichols, John; Meyer, Tricia; Lee, Ho Nyung

    2015-03-01

    Strontium iridate (Srn+1IrnO3n+1) has received lots of attention recently for its potential to reveal novel physical phenomena due to strong spin-orbital coupling with an interaction energy comparable to that of the on-site Coulomb interaction and crystal field splitting. The coexistence of fundamental interactions has created an exotic Jeff = 1/2 antiferromagnetic insulating ground state in Sr2IrO4. In particular, it is known that this system can be driven into a metallic state with the simultaneous increase in dimensionality (n) and strain. We have investigated the effects of electron confinement by interfacing strontium iridates with other perovskite oxides. We have synthesized thin film heterostructures, SrIrO3/AMO3 (A = Sr, La; B = Ti, Mn, Rh), layer-by-layer with pulsed laser deposition equipped with reflection high-energy electron diffraction. Based on investigations with x-ray diffraction, dc transport, SQUID magnetometry, and various spectroscopic measurements, we will present that the physical properties of the heterostructures are strongly dependent on spatial confinement and epitaxial strain. *This work was supported by the U. S. Department of Energy, Office of Science, Basic Energy Sciences, Materials Science and Engineering Division.

  14. Measurement of the physical properties of the snowpack

    NASA Astrophysics Data System (ADS)

    Kinar, N. J.; Pomeroy, J. W.

    2015-06-01

    This paper reviews measurement techniques and corresponding devices used to determine the physical properties of the seasonal snowpack from distances close to the ground surface. The review is placed in the context of the need for scientific observations of snowpack variables that provide inputs for predictive hydrological models that help to advance scientific understanding of geophysical processes related to snow in the near-surface cryosphere. Many of these devices used to measure snow are invasive and require the snowpack to be disrupted, thereby precluding the possibility for multiple measurements to be made at the same sampling location. Moreover, many devices rely on the use of empirical calibration equations that may not be valid at all geographic locations. The spatial density of observations with most snow measurement devices is often inadequate. There is a need for improved automation of snowpack measurement instrumentation with an emphasis on field-based feedback of measurement validity in lieu of postprocessing of samples or data at a lab or office location. The scientific future of snow measurement instrumentation thereby requires a synthesis between science and engineering principles that takes into consideration geophysics and the physics of device operation.

  15. The physical properties of the interstellar cloud around the heliosphere

    NASA Astrophysics Data System (ADS)

    Gry, C.

    2015-12-01

    A new interpretation of interstellar absorption lines in the spectra of nearby stars indicates that the medium surrounding the Sun can be regarded as a single, coherent cloud if we relax the assumption that a cloud behaves like a rigid body. This outlook permits us to construct a comprehensive picture of the local interstellar cloud and reveals that it departs from homogeneity in a number of aspects and physical properties: - This local cloud undergoes a deformation related to a compression in the direction of motion and an expansion in perpendicular directions, much like a squashed balloon. - The metal abundances decrease steadily from the rear to the head of the cloud, and this phenomenon does not appear to be related to ionization effects. - The cloud average HI density, estimated toward a number of nearby stars around which an astrophere is detected in Lyman alpha, varies from 0.03 to 0.1 cm-3. The cloud outer boundary inferred from the average density and column densities is very irregular with an average distance to the Sun of 9 +/- 7 pc. - The electron density and the cloud temperature can be derived from the combination of the ionization equilibrium of MgI and the excitation of CII in a restricted number of sightlines where column density is such that MgI and CII* features are strong enough to be detectable without saturating MgII. We present a few additional targets from which we examine the physical conditions inside the cloud.

  16. [Making tablets of powdered milk and the physical properties].

    PubMed

    Shibata, Mitsuho; Otsubo, Kazumitsu; Nakane, Shota; Niwa, Toshiyuki; Danjo, Kazumi

    2011-01-01

    Compressed baby milk powder has proven to be very convenient for parents due to the ease with which it can be handled, and the fact that use of a measuring scoop is not necessary. The purpose of this study was to develop a compressed baby milk powder and analyze the resulting physical properties. The basic production process consisted of the following steps: 1) molding milk powder by low compression pressure, 2) humidification at 25°C·97%RH and 3) drying with use of a desiccant. No chemical additives were used for solidification; therefore the chemical composition of the compressed milk powder is identical to the base milk powder. The important properties of the compressed milk powder are both ready solubility and the strength of the solid. The compressed milk powder obtained at low pressure was too brittle for practical use, but the strength was increased by humidification followed by drying. During the humidification process, the powder particles located close to the surface of the compressed milk powder partially dissolve resulting in bridging structures between the particles, leading to an increase in strength. Both specific surface area and the volume ratio of the compressed milk powder decreased. Testing showed that caking between the particles occurred following humidification, and that the volume of caking affected the ease with which the compressed milk powder dissolves in water. PMID:21963978

  17. Physical Properties of Volcanic Deposits on Venus from Radar Polarimetry

    NASA Technical Reports Server (NTRS)

    Carter, Lynn M.; Campbell, Donald B.; Campbell, Bruce A.

    2005-01-01

    Studies of the morphology and radar properties of volcanic deposits can aid in understanding their differences and formation. On Venus, volcanoes range in size from large highland edifices, such as Theia Mons, to small shields and domes which are often found in groups of tens to hundreds. In plains regions, windstreaks are sometimes found near shield fields, suggesting that there may be fine grained deposits associated with the volcanoes. Previous studies of Bell Regio suggest the presence of fine-grained material in a low dielectric constant triangular shaped region on the flank of Tepev Mons, which may be crater ejecta or a pyroclastic deposit spread westward by wind. The eastern caldera on Tepev Mons shows a steep trend in backscattered power with incidence angle and has high RMS-slopes, implying a finegrained covering such as ash. Radar waves can easily penetrate smooth mantling layers such as ash and aeolian deposits. If a radar system can measure two orthogonal polarizations, it is possible to detect subsurface scattering and infer the presence of surficial deposits. The Magellan spacecraft could only measure one polarization and was therefore not able to fully characterize the polarization state of the radar echoes. We compare Arecibo dual-polarization data for Venus to Magellan images and emissivity data to investigate the physical properties of volcanic deposits.

  18. Physical properties of intermetallic iron(2) vanadium aluminide

    NASA Astrophysics Data System (ADS)

    Feng, Ye

    2001-11-01

    Fe2VAl has recently been discovered to have a negative temperature coefficient of resistivity, moderately enhanced specific heat coefficient, and a large DOS at the Fermi level by photoemission. This triggered a round of heated research to understand the ground state of this material, both theoretically and experimentally. Here we report a comprehensive characterization of Fe2VAl. X-ray diffraction exhibited appreciable antisite disorder in all of our samples. FTIR spectroscopy measurements showed that the carrier density and scattering time had little sample-to-sample variation or temperature dependence for near-stoichiometric samples. FTIR and DC resistivity suggest that the transport properties of Fe2VAl are influenced by both localized and delocalized carriers, with the former primarily responsible for the negative temperature coefficient of resistivity. Magnetization measurements reveal that near-stoichiometric samples have superparamagnetic clusters with at least two sizes of moments. X-ray photoemission from Fe core level shows localized magnetic moments on site-exchanged Fe. We conclude that in Fe 2VAl, antisite disorder causes significant modification to the semi-metallic band structure proposed by LDA calculations. With antisite disorder considered, we are now able to explain most of the physical properties of Fe2VAl.

  19. Physical Properties of Intermetallic FE2VA1

    SciTech Connect

    Ye Feng

    2002-05-30

    Fe{sub 2}VAl has recently been discovered to have a negative temperature coefficient of resistivity, moderately enhanced specific heat coefficient, and a large DOS at the Fermi level by photoemission. This triggered a round of heated research to understand the ground state of this material, both theoretically and experimentally. here they report a comprehensive characterization of Fe{sub 2}VAl. X-ray diffraction exhibited appreciable antisite disorder in all of our samples. FTIR spectroscopy measurements showed that the carrier density and scattering time had little sample-to-sample variation or temperature dependence for near-stoichiometric samples. FTIR and DC resistivity suggest that the transport properties of Fe{sub 2}VAl are influenced by both localized and delocalized carriers, with the former primarily responsible for the negative temperature coefficient of resistivity. Magnetization measurements reveal that near-stoichiometric samples have superparamagnetic clusters with at least two sizes of moments. X-ray photoemission from Fe core level showed localized magnetic moments on site-exchanged Fe. They conclude that in Fe{sub 2}VAl, antisite disorder causes significant modification to the semi-metallic band structure proposed by LDA calculations. With antisite disorder considered, they are now able to explain most of the physical properties of Fe{sub 2}VAl.

  20. Orbits and Physical Properties of Four Binary Transneptunian Objects

    NASA Astrophysics Data System (ADS)

    Grundy, William

    2014-10-01

    Intriguing patterns are evident in both the orbits of transneptunian objects and in their observable external characteristics (colors, spectral features, etc.). Bulk physical properties are needed to make sense of the observations and to exploit them to constrain conditions in the protoplanetary disk where these objects formed. The key to obtaining bulk properties of transneptunian objects is that a sizeable proportion of them are binaries. Binary mutual orbits provide dynamical masses that can in turn be used to compute bulk densities. A statistical sample of binary orbits offers powerful constraints on formation mechanisms as well as subsequent evolution. This proposal seeks to continue a multi-year campaign to obtain orbits for as large of a sample of binary transneptunian objects as possible. We seek to make efficient use of HST by targeting four systems where we can obtain a dramatic improvement in orbital knowledge from relatively few, strategically timed visits, and where the secondary is too faint for reliable detection with ground-based near-IR adaptive optics techniques.

  1. Nanoscale memristive radiofrequency switches.

    PubMed

    Pi, Shuang; Ghadiri-Sadrabadi, Mohammad; Bardin, Joseph C; Xia, Qiangfei

    2015-01-01

    Radiofrequency switches are critical components in wireless communication systems and consumer electronics. Emerging devices include switches based on microelectromechanical systems and phase-change materials. However, these devices suffer from disadvantages such as large physical dimensions and high actuation voltages. Here we propose and demonstrate a nanoscale radiofrequency switch based on a memristive device. The device can be programmed with a voltage as low as 0.4 V and has an ON/OFF conductance ratio up to 10(12) with long state retention. We measure the radiofrequency performance of the switch up to 110 GHz and demonstrate low insertion loss (0.3 dB at 40 GHz), high isolation (30 dB at 40 GHz), an average cutoff frequency of 35 THz and competitive linearity and power-handling capability. Our results suggest that, in addition to their application in memory and computing, memristive devices are also a leading contender for radiofrequency switch applications. PMID:26108890

  2. Electrodeposition of zinc oxide nanowires: Growth, doping, and physical properties

    NASA Astrophysics Data System (ADS)

    Thomas, Matthew Allan

    As a transparent, wide bandgap semiconductor, ZnO offers an expansive range of potential uses in various technological arenas such as electronics, optoelectronics, photonics, sensors, and energy conversion. However, a current obstacle to the realization of ZnO based electronics and optoelectronics is the lack of a reliable and reproducible method for fabricating high quality p-type ZnO. In addition, there remains a difficulty in tuning the various properties of ZnO materials, especially nanostructures, via low cost and low temperature deposition techniques. In this work, some of these deficiencies have been addressed. Undoped and Ag-doped ZnO nanowires, as well as highly uniform and dense ZnO films, were obtained by an inexpensive, low temperature, electrochemical technique in aqueous solution. The effects of electrochemical growth conditions and Ag-doping on the structural, optical, and electrical properties of the ZnO nanowires were investigated in detail. Ag-doping was found to induce significant changes in the various physical properties of the ZnO nanowires. Importantly, a range of experimental and theoretical results indicate Ag is doped into the ZnO nanowire structure and leads to p-type properties of the nanowires. The room temperature photoluminescence (PL) of the nanowires illustrates bandgap reduction, while intense emissions from a free electron to neutral acceptor were induced in the low temperature PL upon Ag-doping. The electrical properties of the Ag-doped nanowires were probed with photoelectrochemical cell measurements, providing further evidence for their p-type nature. The mechanism of Ag-doping in the nanowires was explored with cyclic voltammetry (CV), X-ray photoelectron spectroscopy (XPS), and density functional theory (DFT) calculations. Interestingly, the presence of Ag+ in the growth process catalyzes and enhances the electrochemistry, shifting the ZnO growth conditions to an O-rich environment. These conditions enable a more efficient Ag

  3. Statistics of physical properties of dark matter clusters

    SciTech Connect

    Shaw, Laurie; Weller, Jochen; Ostriker, Jeremiah P.; Bode, Paul; /Princeton U. Observ.

    2005-09-01

    We have identified over 2000 well resolved cluster halos, and also their associated bound subhalos, from the output of 1024{sup 3} particle cosmological N-body simulation (of box size 320h{sup -1}Mpc and softening length 3.2h{sup -1}kpc). We present an algorithm to identify those halos still in the process of relaxing into dynamical equilibrium, and a detailed analysis of the integral and internal physical properties for all the halos in our sample. The majority are prolate, and tend to rotate around their minor principle axis. We find there to be no correlation between the spin and virial mass of the clusters halos and that the higher mass halos are less dynamically relaxed and have a lower concentration. Additionally, the orbital angular momentum of the substructure is typically well aligned with the rotational angular momentum of the ''host'' halo. There is also evidence of the transfer of angular momentum from subhalos to their host. Overall, we find that measured halo properties are often significantly influenced by the fraction of mass contained within substructure. Dimensionless properties do depend weakly on the ratio of halo mass (M{sub h}) to our characteristic mass scale (M{sub *} = 8 x 10{sup 14}h{sup -1}M{sub {circle_dot}}). This lack of self-similarity is in the expected sense in that, for example, ''old halos'' with M{sub h}/M{sub *} << 1 have less substructure than ''young halos'' with M{sub h}/M{sub *} >> 1.

  4. Recovering physical properties from narrow-band photometry

    NASA Astrophysics Data System (ADS)

    Schoenell, W.; Cid Fernandes, R.; Benítez, N.; Vale Asari, N.

    2013-05-01

    Our aim in this work is to answer, using simulated narrow-band photometry data, the following general question: What can we learn about galaxies from these new generation cosmological surveys? For instance, can we estimate stellar age and metallicity distributions? Can we separate star-forming galaxies from AGN? Can we measure emission lines, nebular abundances and extinction? With what precision? To accomplish this, we selected a sample of about 300k galaxies with good S/N from the SDSS and divided them in two groups: 200k objects and a template library of 100k. We corrected the spectra to z = 0 and converted them to filter fluxes. Using a statistical approach, we calculated a Probability Distribution Function (PDF) for each property of each object and the library. Since we have the properties of all the data from the STARLIGHT-SDSS database, we could compare them with the results obtained from summaries of the PDF (mean, median, etc). Our results shows that we retrieve the weighted average of the log of the galaxy age with a good error margin (σ ≈ 0.1 - 0.2 dex), and similarly for the physical properties such as mass-to-light ratio, mean stellar metallicity, etc. Furthermore, our main result is that we can derive emission line intensities and ratios with similar precision. This makes this method unique in comparison to the other methods on the market to analyze photometry data and shows that, from the point of view of galaxy studies, future photometric surveys will be much more useful than anticipated.

  5. Fire effects on physical properties of Andisols (Tenerife, Canary Islands)

    NASA Astrophysics Data System (ADS)

    Neris, J.; Tejedor, M.; Jiménez, C.

    2012-04-01

    Forest fires modify the main properties of affected soils. Soil physical properties of Andisols with pine forest burned were evaluated. Five burned zones were compared to unburned counterparts. Soil texture, structure, bulk density, water retention capacity and water repellency were determined. As most studies report, soils showed an increase in the sand and/or silt content related to a noticeably reduction in clay content in the zones affected by fire. According to these reports, cementation processes involving Al and Si hydroxides as cements during the fire are the main factors controlling this behaviour. Regarding to soil structure, aggregation and aggregate stability decreased considerably in burned zones, as is usually reported. The decrease in soil binding such as organic matter, clay content and short-range order products explains this trend. Nevertheless, bulk density and water retention capacity, some of the main characteristic properties of Andisols, showed contradictory patterns compared to most studies. Water retention capacity at -33 kPa increases considerably after fire, whereas at -1500 kPa no major changes were observed. Preliminary conclusions indicate that the high water retention of ashes included into the soil explains this trend at -33 kPa. On the other side, the decrease in organic matter and clay content offsets the water retention increase at -1500 kPa due the ash incorporation. In opposition to most studies, an important reduction in bulk density was observed in burned soils. Some authors have reported that the desiccation process leads to a loss of aggregation resulting in low-density microaggregates in Andisols of Tenerife. These soils are known locally as "dusty-soils". Finally, a decrease of soil water repellency was also observed in most zones after fire, despite a large number of studies reporting the opposite. The soil organic matter decline might be the key factor of this trend.

  6. Physical and optical properties of persistent contrails: Climatology and interpretation

    NASA Astrophysics Data System (ADS)

    Iwabuchi, Hironobu; Yang, Ping; Liou, K. N.; Minnis, Patrick

    2012-03-01

    The physical and optical properties of persistent contrails were studied with the measurements made by the Moderate Resolution Imaging Spectroradiometer (MODIS) and the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) lidar. MODIS data were used to determine the contrail locations on the basis of their artificial shapes easily distinguished from natural cirrus, and the so-identified contrails were analyzed with collocated CALIPSO lidar data. Statistics of the geography, geometry, meteorology, and optical properties are reported for approximately 3400 persistent contrails observed over North America, the North Atlantic Ocean, and Europe. The majority of the detected contrails appear in ice-supersaturated air with temperatures lower than -40°C. On average, contrails have significantly larger backscattering coefficients and slightly higher linear depolarization ratios (LDRs) than neighboring cirrus clouds. Depolarization tends to be strong when ice crystals are small, and LDR is approximately 0.4-0.45 for young contrails and contrail cores. The mean LDR for the detected contrails increases with decreasing temperature and is not strongly dependent on the lidar pointing angle. The backscattering properties suggest that contrails are primarily composed of small, randomly oriented ice crystals but may also contain a few horizontally oriented plates. Most contrails are optically thin with a mean (median) optical thickness of approximately 0.19 (0.14); however, optically thicker contrails do exist and tend to occur in warmer and more humid ambient air. The mean value and range of the observed LDR data are consistent with theoretical predictions based on a mixture of nonspherical ice crystals randomly oriented in the atmosphere.

  7. Hardrock Elastic Physical Properties: Birch's Seismic Parameter Revisited

    NASA Astrophysics Data System (ADS)

    Wu, M.; Milkereit, B.

    2014-12-01

    Identifying rock composition and properties is imperative in a variety of fields including geotechnical engineering, mining, and petroleum exploration, in order to accurately make any petrophysical calculations. Density is, in particular, an important parameter that allows us to differentiate between lithologies and estimate or calculate other petrophysical properties. It is well established that compressional and shear wave velocities of common crystalline rocks increase with increasing densities (i.e. the Birch and Nafe-Drake relationships). Conventional empirical relations do not take into account S-wave velocity. Physical properties of Fe-oxides and massive sulfides, however, differ significantly from the empirical velocity-density relationships. Currently, acquiring in-situ density data is challenging and problematic, and therefore, developing an approximation for density based on seismic wave velocity and elastic moduli would be beneficial. With the goal of finding other possible or better relationships between density and the elastic moduli, a database of density, P-wave velocity, S-wave velocity, bulk modulus, shear modulus, Young's modulus, and Poisson's ratio was compiled based on a multitude of lab samples. The database is comprised of isotropic, non-porous metamorphic rock. Multi-parameter cross plots of the various elastic parameters have been analyzed in order to find a suitable parameter combination that reduces high density outliers. As expected, the P-wave velocity to S-wave velocity ratios show no correlation with density. However, Birch's seismic parameter, along with the bulk modulus, shows promise in providing a link between observed compressional and shear wave velocities and rock densities, including massive sulfides and Fe-oxides.

  8. Physical properties of organic and biomaterials: Fundamentals and applications

    NASA Astrophysics Data System (ADS)

    Steven, Eden

    Silk materials are natural protein-based materials with an exceptional toughness. In addition to their toughness, silk materials also possess complex physical properties and functions resulting from a particular set of amino-acid arrangement that produces structures with crystalline beta-sheets connected by amorphous chains. Extensive studies have been performed to study their structure-function relationship leading to recent advancements in bio-integrated devices. Applications to fields other than textiles and biomedicine, however, have been scarce. In this dissertation, an investigation of the electronic properties, functionalization, and role of silk materials (spider silk and Bombyx mori cocoon silk) in the field of organic materials research is presented. The investigation is conducted from an experimental physics point of view where correlations with charge transport mechanisms in disordered, semiconducting, and insulating materials are made when appropriate. First, I present the electronic properties of spider silk fibers under ambient, humidified, iodized, polar solvent exposure, and pyrolized conditions. The conductivity is exponentially dependent on relative humidity changes and the solvent polarity. Iodine doping increases the conductivity only slightly but has pronounced effects on the pyrolization process, increasing the yield and flexibility of the pyrolized silk fibers. The iodized samples were further studied using magic angle spinning nuclear magnetic resonance (MAS-NMR) and Fourier transform infrared spectroscopy (FTIR) revealing non-homogenous iodine doping and I2 induced hydrogenation that are responsible for the minimal conductivity improvement and the pyrolization effects, respectively. Next, I present the investigation of silk fiber functionalization with gold and its role in electrical measurements. The gold functionalized silk fiber (Au-SS) is metallic down to cryogenic temperatures, has a certain amount of flexibility, and possesses

  9. Nanoscale surface photoreactions

    NASA Astrophysics Data System (ADS)

    Wadsworth, Garrett Austin

    Subnanometer-scale properties of molecules and materials have become extremely important to the development of nanoscale and molecular electronics devices, including advanced biological and chemical sensors. The energies (i.e., wavelengths) at which the LSPRs of individual nanoparticles are excited varies depending on their size, thickness, and shape, all of which can be controlled synthetically. Photon-coupled scanning tunneling microscopy uses a total internal reflection scheme to couple light into a tunneling junction, generating this specific LSPR in individual Au and Ag nanoprisms. By controlling and coupling this specific excitation to molecular assemblies, the effective photoreactivities and photoconductances of organic molecules can be measured and manipulated. Nanoparticle synthesis methods were developed to produce nanoprisms with appropriate dimensions and homogeneity. Functionalization of the sample surface using alkanedithiols and p-terphenyl-4,4"-dithiol enabled the adsorption dispersion of nanoprisms onto substrates with high density yet minimal stacking. Insertion into self-assembled monolayers was used to arrange single molecules on Au{111} and Ag{111} nanoprisms for selective surface plasmonic enhancement. Scanning tunneling microscopy measurements were collected for molecules adsorbed on the dispersed nanoprisms. Photon STM will be used to monitor the photoactivities of molecules on these substrates, such as photocurrent, photoconductance, and photoreaction.

  10. Physical properties of organic and biomaterials: Fundamentals and applications

    NASA Astrophysics Data System (ADS)

    Steven, Eden

    Silk materials are natural protein-based materials with an exceptional toughness. In addition to their toughness, silk materials also possess complex physical properties and functions resulting from a particular set of amino-acid arrangement that produces structures with crystalline beta-sheets connected by amorphous chains. Extensive studies have been performed to study their structure-function relationship leading to recent advancements in bio-integrated devices. Applications to fields other than textiles and biomedicine, however, have been scarce. In this dissertation, an investigation of the electronic properties, functionalization, and role of silk materials (spider silk and Bombyx mori cocoon silk) in the field of organic materials research is presented. The investigation is conducted from an experimental physics point of view where correlations with charge transport mechanisms in disordered, semiconducting, and insulating materials are made when appropriate. First, I present the electronic properties of spider silk fibers under ambient, humidified, iodized, polar solvent exposure, and pyrolized conditions. The conductivity is exponentially dependent on relative humidity changes and the solvent polarity. Iodine doping increases the conductivity only slightly but has pronounced effects on the pyrolization process, increasing the yield and flexibility of the pyrolized silk fibers. The iodized samples were further studied using magic angle spinning nuclear magnetic resonance (MAS-NMR) and Fourier transform infrared spectroscopy (FTIR) revealing non-homogenous iodine doping and I2 induced hydrogenation that are responsible for the minimal conductivity improvement and the pyrolization effects, respectively. Next, I present the investigation of silk fiber functionalization with gold and its role in electrical measurements. The gold functionalized silk fiber (Au-SS) is metallic down to cryogenic temperatures, has a certain amount of flexibility, and possesses

  11. 41 CFR 109-1.5107 - Physical protection of personal property.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 41 Public Contracts and Property Management 3 2013-07-01 2013-07-01 false Physical protection of personal property. 109-1.5107 Section 109-1.5107 Public Contracts and Property Management Federal Property Management Regulations System (Continued) DEPARTMENT OF ENERGY PROPERTY MANAGEMENT REGULATIONS GENERAL...

  12. 41 CFR 109-1.5110 - Physical inventories of personal property.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 41 Public Contracts and Property Management 3 2012-01-01 2012-01-01 false Physical inventories of personal property. 109-1.5110 Section 109-1.5110 Public Contracts and Property Management Federal Property Management Regulations System (Continued) DEPARTMENT OF ENERGY PROPERTY MANAGEMENT REGULATIONS GENERAL...

  13. 41 CFR 109-1.5110 - Physical inventories of personal property.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 41 Public Contracts and Property Management 3 2013-07-01 2013-07-01 false Physical inventories of personal property. 109-1.5110 Section 109-1.5110 Public Contracts and Property Management Federal Property Management Regulations System (Continued) DEPARTMENT OF ENERGY PROPERTY MANAGEMENT REGULATIONS GENERAL...

  14. 41 CFR 109-1.5107 - Physical protection of personal property.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 41 Public Contracts and Property Management 3 2012-01-01 2012-01-01 false Physical protection of personal property. 109-1.5107 Section 109-1.5107 Public Contracts and Property Management Federal Property Management Regulations System (Continued) DEPARTMENT OF ENERGY PROPERTY MANAGEMENT REGULATIONS GENERAL...

  15. Bumpy, Sticky, and Shaky: Nanoscale Science and the Curriculum

    ERIC Educational Resources Information Center

    Taylor, Amy; Jones, Gail; Pearl, Thomas P.

    2008-01-01

    Nanoscience, or the study of the world at the size of a billionth of a meter, has the potential to help students see how all of the sciences are related. Behavior of materials at the nanoscale differs from materials at the macroscale. This article introduces three nanoscale properties and how they relate to various science domains. Three…

  16. 41 CFR 109-1.5110 - Physical inventories of personal property.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... items indicates that this action is necessary for effective property accounting, utilization, or control... property records, and with applicable financial control accounts. (j) The results of physical inventories...-INTRODUCTION 1.51-Personal Property Management Standards and Practices § 109-1.5110 Physical inventories...

  17. Physical and Mechanical Properties of Composites and Light Alloys Reinforced with Detonation Nanodiamonds

    NASA Astrophysics Data System (ADS)

    Sakovich, G. V.; Vorozhtsov, S. A.; Vorozhtsov, A. B.; Potekaev, A. I.; Kulkov, S. N.

    2016-07-01

    The influence of introduction of particles of detonation-synthesized nanodiamonds into composites and aluminum-base light alloys on their physical and mechanical properties is analyzed. The data on microstructure and physical and mechanical properties of composites and cast aluminum alloys reinforced with diamond nanoparticles are presented. The introduction of nanoparticles is shown to result in a significant improvement of the material properties.

  18. 41 CFR 109-1.5107 - Physical protection of personal property.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 41 Public Contracts and Property Management 3 2010-07-01 2010-07-01 false Physical protection of... Management Regulations System (Continued) DEPARTMENT OF ENERGY PROPERTY MANAGEMENT REGULATIONS GENERAL 1-INTRODUCTION 1.51-Personal Property Management Standards and Practices § 109-1.5107 Physical protection...

  19. 41 CFR 109-1.5107 - Physical protection of personal property.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 41 Public Contracts and Property Management 3 2014-01-01 2014-01-01 false Physical protection of... Management Regulations System (Continued) DEPARTMENT OF ENERGY PROPERTY MANAGEMENT REGULATIONS GENERAL 1-INTRODUCTION 1.51-Personal Property Management Standards and Practices § 109-1.5107 Physical protection...

  20. 41 CFR 109-1.5107 - Physical protection of personal property.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 41 Public Contracts and Property Management 3 2011-01-01 2011-01-01 false Physical protection of... Management Regulations System (Continued) DEPARTMENT OF ENERGY PROPERTY MANAGEMENT REGULATIONS GENERAL 1-INTRODUCTION 1.51-Personal Property Management Standards and Practices § 109-1.5107 Physical protection...

  1. GLYCOLIC ACID PHYSICAL PROPERTIES, IMPURITIES, AND RADIATION EFFECTS ASSESSMENT

    SciTech Connect

    Lambert, D.; Pickenheim, B.; Hay, M.

    2011-06-20

    The Defense Waste Processing Facility (DWPF) is pursuing alternative reductants/flowsheets to increase attainment to meet closure commitment dates. In fiscal year 2009, SRNL evaluated several options and recommended the further assessment of the nitric/formic/glycolic acid flowsheet. SRNL is currently performing testing with this flowsheet to support the DWPF down-select of alternate reductants. As part of the evaluation, SRNL was requested to determine the physical properties of formic and glycolic acid blends. Blends of formic acid in glycolic acid were prepared and their physical properties tested. Increasing amounts of glycolic acid led to increases in blend density, viscosity and surface tension as compared to the 90 wt% formic acid that is currently used at DWPF. These increases are small, however, and are not expected to present any difficulties in terms of processing. The effect of sulfur impurities in technical grade glycolic acid was studied for its impact on DWPF glass quality. While the glycolic acid specification allows for more sulfate than the current formic acid specification, the ultimate impact is expected to be on the order of 0.03 wt% sulfur in glass. Note that lower sulfur content glycolic acid could likely be procured at some increased cost if deemed necessary. A paper study on the effects of radiation on glycolic acid was performed. The analysis indicates that substitution of glycolic acid for formic acid would not increase the radiolytic production rate of H{sub 2} and cause an adverse effect in the SRAT or SME process. It has been cited that glycolic acid solutions that are depleted of O{sub 2} when subjected to large radiation doses produced considerable quantities of a non-diffusive polymeric material. Considering a constant air purge is maintained in the SRAT and the solution is continuously mixed, oxygen depletion seems unlikely, however, if this polymer is formed in the SRAT solution, the rheology of the solution may be affected and

  2. Physical and Orbital Properties of Some of Saturn's Small Satellites

    NASA Astrophysics Data System (ADS)

    Porco, C. C.; Thomas, P.; Spitale, J.; Jacobson, R. A.; Denk, T.; Charnoz, S.; Richardson, D. C.; Dones, L.; Baker, E.; Weiss, J. W.

    2005-08-01

    We present Cassini imaging results on the orbits and physical properties for the small ring-region moons Pan, Atlas, and the Cassini-discovered Keeler gap moon, S/2005 S1 (1), as well as the newly discovered/recovered moons orbiting among the major satellites, Methone (S/2004 S1), Pallene (S/2004 S2), and the Dione co-orbital S/2004 S5 Polydeuces (2,3,4). We find that Atlas is undergoing a 700-km amplitude longitudinal perturbation by Prometheus, Methone is undergoing a 30,000-km amplitude longitudinal perturbation by Mimas, and Pallene is undergoing a long-term 75-km amplitude longitudinal perturbation by Enceladus. Orbital integrations involving Atlas return a mass of GMAtlas = (0.43 ± 0.18) X 10-3 km3/sec2, three times larger than previously reported (4). Reasonably high resolution images have also allowed refinement of physical dimensions and spectral properties of these small moons. Results will be presented. At the time of writing, we find that Atlas has polar and equatorial diameters of 19 km, 38 km and 46 km, respectively. Its volume is (1.5 ± 0.4) X 104 km3, yielding a density of 0.43 ± 0.20 gm/cm3. Pan's polar diameter is 23 km, and differences in its equatorial axes are not well constrained; they both appear to be ˜ 35 km. Pan's volume is (1.4 ± 0.7) X 104 km3. Using the most currently reliable mass, GMPan = (0.33 ± 0.05) × 10-3 km3/sec2 (4), Pan's density is roughly 0.4 ± 0.2 gm/cm3. Both Pan and Atlas appear to be synchronous rotators, but libration cannot be ruled out yet. Given its shape, it is possible that Atlas is in a secondary spin-orbit resonance that could force a libration. Preliminary idealized rubble pile simulations have been performed which show that, at the orbits of Atlas and Pan, a simple self-gravitating ice-particle aggregate, with equal equatorial dimensions, would be stable against tides; a body with sufficiently unequal equatorial dimensions would not. [1] IAUC 8524. [2] IAUC 8389. [Correction: Pallene (S/2004 S2) is the

  3. Evaluation of Physical Properties of Generic and Branded Travoprost Formulations

    PubMed Central

    Wadhwani, Meenakshi; Mishra, Sanjay K; Velpandian, Thirumurthy; Sihota, Ramanjit; Kotnala, Ankita; Bhartiya, Shibal; Dada, Tanuj

    2016-01-01

    ABSTRACT Purpose: Comparative evaluation of pharmaceutical characteristics of three marketed generic vs branded travoprost formulations. Materials and methods: Three generic travoprost formulations and one branded (Travatan without benzalkonium chloride) formulation (10 vials each), obtained from authorized agents from the respective companies and having the same batch number, were used. These formulations were coded and labels were removed. At a standardized room temperature of 25°C, the drop size, pH, relative viscosity, and total drops per vial were determined for Travatan (Alcon, Fort Worth, TX, USA) and all the generic formulations. Travoprost concentration in all four brands was estimated by using liquid chromatography-coupled tandem mass spectrometry LCMS. Results: Out of the four formulations, two drugs (TP 1 and TP 4) were found to follow the United States Pharmacopoeia (USP) limits for ophthalmic formulation regarding drug concentration, while the remaining two drugs failed due to the limits being either above 110% (TP 2) or below 90% (TP 3). Two of them (TP 1 and TP 2) had osmolality of 313 and 262 mOsm respectively, which did not comply with the osmolality limits within 300 mOsm (+ 10%). The pH of all the formulations ranged between 4.7 and 5.9, and the mean drop size was 30.23 ± 6.03 uL. The total amount of drug volume in the bottles varied from 2.58 ± 0.15 to 3.38 ± 0.06 mL/bottle. Conclusion: There are wide variations in the physical properties of generic formulations available in India. Although some generic drugs are compliant with the pharmacopeia standards, this study underscores the need for a better quality control in the production of generic travoprost formulations. How to cite this article: Wadhwani M, Mishra SK, Angmo D, Velpandian T, Sihota R, Kotnala A, Bhartiya S, Dada T. Evaluation of Physical Properties of Generic and Branded Travoprost Formulations. J Curr Glaucoma Pract. 2016;10(2):49-55. PMID:27536047

  4. GLYCOLIC ACID PHYSICAL PROPERTIES, IMPURITIES, AND RADIATION EFFECTS ASSESSMENT

    SciTech Connect

    Pickenheim, B.; Bibler, N.

    2010-06-08

    The DWPF is pursuing alternative reductants/flowsheets to increase attainment to meet closure commitment dates. In fiscal year 2009, SRNL evaluated several options and recommended the further assessment of the nitric/formic/glycolic acid flowsheet. SRNL is currently performing testing with this flowsheet to support the DWPF down-select of alternate reductants. As part of the evaluation, SRNL was requested to determine the physical properties of formic and glycolic acid blends. Blends of formic acid in glycolic acid were prepared and their physical properties tested. Increasing amounts of glycolic acid led to increases in blend density, viscosity and surface tension as compared to the 90 wt% formic acid that is currently used at DWPF. These increases are small, however, and are not expected to present any difficulties in terms of processing. The effect of sulfur impurities in technical grade glycolic acid was studied for its impact on DWPF glass quality. While the glycolic acid specification allows for more sulfate than the current formic acid specification, the ultimate impact is expected to be on the order of 0.03 wt% sulfur in glass. Note that lower sulfur content glycolic acid could likely be procured at some increased cost if deemed necessary. A paper study on the effects of radiation on glycolic acid was performed. The analysis indicates that substitution of glycolic acid for formic acid would not increase the radiolytic production rate of H{sub 2} and cause an adverse effect in the SRAT or SME process. It has been cited that glycolic acid solutions that are depleted of O{sub 2} when subjected to large radiation doses produced considerable quantities of a non-diffusive polymeric material. Considering a constant air purge is maintained in the SRAT and the solution is continuously mixed, oxygen depletion seems unlikely, however, if this polymer is formed in the SRAT solution, the rheology of the solution may be affected and pumping of the solution may be

  5. Mapping Elasticity at the Nanoscale

    NASA Astrophysics Data System (ADS)

    Stan, Gheorghe; Price, William

    2006-03-01

    In the last few years Atomic Force Acoustic Microscopy has been developed to investigate the elastic response of materials at the nanoscale ^[1],[2]. We have extended this technique to the real-time mapping of nanomechanical properties of material surfaces. This mapping allows us to investigate the local variation of elastic properties with nanometer resolution and to reduce the uncertainties that arise from single measurements. Quantitative measurements are acquired by first performing an accurate calibration of the elastic properties of the Atomic Force Microscope’s probes with respect to single crystal reference materials. A wide variety of surfaces with different mechanical properties have been investigated to illustrate the applicability of this technique. ^[1] U. Rabe et al., Surf. Interface Anal. 33 , 65 (2002)^[2] D.C. Hurley et al., J. Appl. Phys. 94, 2347 (2003)

  6. DIET at the nanoscale

    NASA Astrophysics Data System (ADS)

    Dujardin, G.; Boer-Duchemin, E.; Le Moal, E.; Mayne, A. J.; Riedel, D.

    2016-01-01

    We review the long evolution of DIET (Dynamics at surfaces Induced by Electronic Transitions) that began in the 1960s when Menzel, Gomer and Redhead proposed their famous stimulated desorption model. DIET entered the "nanoscale" in the 1990s when researchers at Bell Labs and IBM realized that the Scanning Tunneling Microscope (STM) could be used as an atomic size source of electrons to electronically excite individual atoms and molecules on surfaces. Resonant and radiant Inelastic Electron Tunneling (IET) using the STM have considerably enlarged the range of applications of DIET. Nowadays, "DIET at the nanoscale" covers a broad range of phenomena at the atomic-scale. This includes molecular dynamics (dissociation, desorption, isomerization, displacement, chemical reactions), vibrational spectroscopy and dynamics, spin spectroscopy and manipulation, luminescence spectroscopy, Raman spectroscopy and plasmonics. Future trends of DIET at the nanoscale offer exciting prospects for new methods to control light and matter at the nanoscale.

  7. Fats, Oils, & Colors of a Nanoscale Material

    ERIC Educational Resources Information Center

    Lisensky, George C.; Horoszewski, Dana; Gentry, Kenneth L.; Zenner, Greta M.; Crone, Wendy C .

    2006-01-01

    Phase changes and intermolecular forces are important physical science concepts but are not always easy to present in an active learning format. This article presents several interactive activities in which students plot the melting points of some fatty acids and explore the effect that the nanoscale size and shape of molecules have on the…

  8. SELECTION AND MEASUREMENT OF PHYSICAL PROPERTIES FOR CHARACTERIZATION OF CHEMICAL PROTECTIVE CLOTHING MATERIALS

    EPA Science Inventory

    Chemical protective clothing (CPC) must possess certain physical properties if it is to function as an effective barrier to chemicals. he physical characteristics of CPC materials has gone largely unstudied; most attention has been focussecd on chemical resistance. hysical proper...

  9. Physical and mechanical properties of modified bacterial cellulose composite films

    NASA Astrophysics Data System (ADS)

    Indrarti, Lucia; Indriyati, Syampurwadi, Anung; Pujiastuti, Sri

    2016-02-01

    To open wide range application opportunities of Bacterial Cellulose (BC) such as for agricultural purposes and edible film, BC slurries were blended with Glycerol (Gly), Sorbitol (Sor) and Carboxymethyl Cellulose (CMC). The physical and mechanical properties of BC composites were investigated to gain a better understanding of the relationship between BC and the additive types. Addition of glycerol, sorbitol and CMC influenced the water solubility of BC composite films. FTIR analysis showed the characteristic bands of cellulose. Addition of CMC, glycerol, and sorbitol slightly changed the FTIR spectrum of the composites. Tensile test showed that CMC not only acted as cross-linking agent where the tensile strength doubled up to 180 MPa, but also acted as plasticizer with the elongation at break increased more than 100% compared to that of BC film. On the other hand, glycerol and sorbitol acted as plasticizers that decreased the tensile strength and increased the elongation. Addition of CMC can improve film transparency, which is quite important in consumer acceptance of edible films in food industry.

  10. Influence of moisture content on physical properties of minor millets.

    PubMed

    Balasubramanian, S; Viswanathan, R

    2010-06-01

    Physical properties including 1000 kernel weight, bulk density, true density, porosity, angle of repose, coefficient of static friction, coefficient of internal friction and grain hardness were determined for foxtail millet, little millet, kodo millet, common millet, barnyard millet and finger millet in the moisture content range of 11.1 to 25% db. Thousand kernel weight increased from 2.3 to 6.1 g and angle of repose increased from 25.0 to 38.2°. Bulk density decreased from 868.1 to 477.1 kg/m(3) and true density from 1988.7 to 884.4 kg/m(3) for all minor millets when observed in the moisture range of 11.1 to 25%. Porosity decreased from 63.7 to 32.5%. Coefficient of static friction of minor millets against mild steel surface increased from 0.253 to 0.728 and coefficient of internal friction was in the range of 1.217 and 1.964 in the moisture range studied. Grain hardness decreased from 30.7 to 12.4 for all minor millets when moisture content was increased from 11.1 to 25% db. PMID:23572637

  11. Theoretical study of photo-physical properties of indolylmaleimide derivatives.

    PubMed

    Zheng, ZiLong; Zhao, Yi; Nakazono, Manabu; Nanbu, Shinkoh

    2012-03-01

    Photo-physical properties of bromo-indolylmaleimide (IM-Br), indole-succinimide (IS), and their anions were theoretically investigated compared with the previous theoretical result for indolylmaleimide (IM) [Phys. Chem. Chem. Phys., 2010, 12, 9783]. The energies for the electronic excited states as well as the ground states were computed for these molecules using the multi-reference perturbation calculations based on the second order Rayleigh-Schrödinger perturbation theory (CASPT2) at the cc-pVDZ basis set level. The electron-accepting or electron-donating effect caused by bromine-substitution was discussed in the intra-molecular charge transfer (ICT) mechanism. The order of natural orbitals of the bromine-substituted monovalent anion with a deprotonated indole NH group (I((-))M-Br) was found to be rearranged by the effect of electron-donation, which leads to pseudo-crossing of the potential energy cures of the S(1) and S(2) states. The large stokes shift observed for I((-))M-Br was due to pseudo-crossing. Meanwhile, IM and IM-Br show abnormal deprotonation, which is explained by the charge distribution on the indole and maleimide moieties. Finally, the monovalent anions I((-))M-Br and I((-))M by a deprotonation of the indole NH end and the neutral IS were proposed to be the most feasible candidates corresponding to the experimental spectra in solution. PMID:22293896

  12. Comparative study of the physical properties of core materials.

    PubMed

    Saygili, Gülbin; Mahmali, Sevil M

    2002-08-01

    This study was undertaken to measure physical properties of materials used for direct core buildups, including high-copper amalgam, visible light-cured resin composite, autocured titanium-containing composite, polyacid-modified composite, resin-modified glass-ionomer, and silver cermet cement. Compressive strength, diametral tensile strength, and flexural strength of six core materials of various material classes were measured for each material as a function of time up to 3 months at different storage conditions, using a standard specification test designed for the materials. Three different storage conditions (dry, humid, wet) at 37 degrees C were chosen. Materials were manipulated according to manufacturers' instructions for use as cores. Mean compressive, diametral tensile, and flexural strengths with associated standard deviations were calculated for each material. Multiple comparison and Newman-Keuls tests discerned many differences among materials. All materials were found to meet the minimum specification requirements, except in terms of flexural strength for amalgam after 1 hour and the silver cermet at all time intervals. PMID:12212682

  13. Physical Properties of Near-Earth Asteroid 2011 MD

    NASA Astrophysics Data System (ADS)

    Mommert, M.; Farnocchia, D.; Hora, J. L.; Chesley, S. R.; Trilling, D. E.; Chodas, P. W.; Mueller, M.; Harris, A. W.; Smith, H. A.; Fazio, G. G.

    2014-07-01

    We report on observations of near-Earth asteroid 2011 MD with the Spitzer Space Telescope. We have spent 19.9 hr of observing time with channel 2 (4.5 μm) of the Infrared Array Camera and detected the target within the 2σ positional uncertainty ellipse. Using an asteroid thermophysical model and a model of nongravitational forces acting upon the object, we constrain the physical properties of 2011 MD, based on the measured flux density and available astrometry data. We estimate 2011 MD to be (6+4-2) m in diameter with a geometric albedo of 0.3+0.4-0.2 (uncertainties are 1σ). We find the asteroid's most probable bulk density to be (1.1+0.7-0.5) g cm-3, which implies a total mass of (50-350) t and a macroporosity of >=65%, assuming a material bulk density typical of non-primitive meteorite materials. A high degree of macroporosity suggests that 2011 MD is a rubble-pile asteroid, the rotation of which is more likely to be retrograde than prograde.

  14. Physical properties of cage-like compound UB12

    NASA Astrophysics Data System (ADS)

    Troć, R.; Wawryk, R.; Pikul, A.; Shitsevalova, N.

    2015-07-01

    Boron and uranium form three metallic borides having the chemical formulae UB2, UB4 and UB12. In this study, we present the temperature variations of magnetic susceptibility, specific heat, electrical resistivity (performed in magnetic fields of 0 and up to 9 T), thermoelectric power and thermal conductivity measured on the bulk sample of UB12. This dodecaboride behaves as a typical metal, being a Pauli paramagnet and exhibiting a large variety of physical properties due to its specific close-packed structure containing B12 groups. We describe also an uncommon phenomenon observed in UB12, that is, a fairly large scattering of the experimental resistivity data under application of a magnetic field at low temperatures and its systematic vanishing during heating of the sample. This effect is probably caused by inharmonious movement (rattling) of the uranium atoms inside the oversized coordination cage, B24, reflected by applying the magnetic field. The specific heat, resistivity, thermoelectric power and heat transport data have been analysed in the framework of the low-frequency Einstein modes, which are mainly responsible for the phonon spectra behaviour in the system studied here.

  15. Prediction of pollutant physical properties by computer (SPARC)

    SciTech Connect

    Karickhoff, S.W.; Careirra, L.A.; Hilal, S.H.

    1995-12-31

    The SPARC system provides estimates of key chemical parameters required in the description of physical/chemical processes that affect the speciation, transport and transformation of organic pollutants in the environment. The span in chemical parameters includes ionization pKa`s and equilibrium constants for interphase distribution (gas/liquid, liquid/liquid, liquid/solid, etc.). Predictive capability extends to essentially any organic solute and derives strictly from molecular structure input. Solvents capability includes water and essentially any organic solvent. Reaction conditions span ranges typical of environmental application. All parameter calculations derive from a common set of core models describing intra/intermolecular interactions. In this presentation, salvation models will be highlighted. These include both inner and outer shell interactions. Results of these salvation models in estimating solute activities and activity-derived properties (solubilities, vapor pressures, distribution coefficients) will be given for a wide range of solutes, solvents and solvent mixtures. The extension of these salvation models to sorption on natural sorbents will be presented.

  16. Flow-specific physical properties of coconut flours

    NASA Astrophysics Data System (ADS)

    Manikantan, Musuvadi R.; Kingsly Ambrose, Rose P.; Alavi, Sajid

    2015-10-01

    Coconut milk residue and virgin coconut oil cake are important co-products of virgin coconut oil that are used in the animal feed industry. Flour from these products has a number of potential human health benefits and can be used in different food formulations. The objective of this study was to find out the flow-specific physical properties of coconut flours at three moisture levels. Coconut milk residue flour with 4.53 to 8.18% moisture content (w.b.) had bulk density and tapped density of 317.37 to 312.65 and 371.44 to 377.23 kg m-3, respectively; the corresponding values for virgin coconut oil cake flour with 3.85 to 7.98% moisture content (wet basis) were 611.22 to 608.68 and 663.55 to 672.93 kg m-3, respectively. The compressibility index and Hausner ratio increased with moisture. The angle of repose increased with moisture and ranged from 34.12 to 36.20 and 21.07 to 23.82° for coconut milk residue flour and virgin coconut oil cake flour, respectively. The coefficient of static and rolling friction increased with moisture for all test surfaces, with the plywood offering more resistance to flow than other test surfaces. The results of this study will be helpful in designing handling, flow, and processing systems for coconut milk residue and virgin coconut oil cake flours.

  17. Physical properties of molecular clouds in the southern outer Galaxy.

    NASA Astrophysics Data System (ADS)

    May, J.; Alvarez, H.; Bronfman, L.

    1997-11-01

    We have used a deep CO survey of the third galactic quadrant (May et al., 1993A&AS...99..105M) to derive the physical properties of molecular clouds in the outer Galaxy. Within the range of this survey, from 194° to 270° in galactic longitude, 177 molecular clouds have been identified beyond 2kpc from the Sun. Distances have been determined kinematically using the rotation curve of Brand (1986, Ph.D. Thesis, University of Leiden) with Rsun_=8.5kpc and {THETA}sun_=220km/s. Power-law relations between line widths and sizes of the clouds, and between their densities and sizes have been found, although they do not fulfill exactly the requirements to be in virial equilibrium. Adopting a CO luminosity-to-H_2_ conversion factor X=3.8x10^20^molecules/cm^2^/(K.km/s), the derived M_CO_ masses statistically agree with the virial masses. The derived size and mass distributions show that the clouds are smaller, less massive and with narrower lines than those in the inner Galaxy. However, the mass spectrum for the clouds in our sample with masses >=2.5x10^4^Msun_ has a slope -1.45 which is similar to that found for inner Galaxy clouds. The warping and flaring of the outer molecular disk is clearly delineated.

  18. Properties and hydration products of lightweight and expansive cements. Part I: Physical and mechanical properties

    SciTech Connect

    Lilkov, V.; Djabarov, N.; Bechev, G.; Kolev, K.

    1999-10-01

    Results from studies on the physical and mechanical properties of lightweight and expansive cements cured at 20 and 75 C are presented. Lightweight additive (cenospheres from thermoelectric power station Bobov Dol, Bulgaria) and expansive additive (Bulexa with hydroxide type of expansion) were used. The compressive and flexural strength, the gas and water impermeability, and the pore structure of the cement stone of lightweight and expansive cements were investigated. The results are compared with corresponding parameters of cement stone without additives. It was found that the cenospheres are appropriate lightweight additives. The use of expansive additive helps overcome the dry shrinkage of cement stone and strengthens the bond with the bounding surfaces.

  19. Physical property characterization of a damage zone in granitic rock - Implications for geothermal reservoir properties

    NASA Astrophysics Data System (ADS)

    Wenning, Quinn; Madonna, Claudio; Amann, Florian; Gischig, Valentin; Burg, Jean-Pierre

    2016-04-01

    Geothermal energy offers a viable alternative to mitigate greenhouse gas emitting energy production. A tradeoff between less expensive drilling costs and increased permeability at shallow depths versus increased heat production at deeper depths stipulates the economic energy potential of a given reservoir. From a geological perspective, successful retrieval of geothermal energy from the subsurface requires sufficient knowledge of the structural and stratigraphic relationship of the target formations, which govern the thermal conditions, physical properties, and fluid flow properties of reservoir rocks. In Switzerland, deep basement rocks (~5 km) with fluid conducting damage zones and enhanced fractured systems stimulated by hydraulic shearing are seen as a potential geothermal reservoir system. Damage zones, both natural and induced, provide permeability enhancement that is especially important for creating fluid conductivity where the matrix permeability is low. This study concentrates on characterizing the elastic and transport properties entering into a natural damage zone penetrated by a borehole at the Grimsel underground research laboratory. The borehole drilled from a cavern at 480 m below ground surface penetrates approximately 20 m of mostly intact Grimsel granodiorite before entering the first phyllosilicate-rich shear zone (~0.2 m thick). The borehole intersects a second shear zone at approximately 23.8m. Between the two shear zones the Grimsel granodiorite is heavily fractured. The minimum principle stress magnitude from in-situ measurements decreases along the borehole into the first shear zone. Two mutually perpendicular core samples of Grimsel granodiorite were taken every 0.1 m from 19.5 to 20.1 m to characterize the physical properties and anisotropy changes as a gradient away from the damage zone. Measurements of ultrasonic compressional (Vp) and shear (Vs) velocities at 1 MHz frequency are conducted at room temperature and hydrostatic pressures

  20. Phase stability of zirconia at nanoscale.

    NASA Astrophysics Data System (ADS)

    Sabiryanov, Renat; Mei, W. N.

    2004-03-01

    There are three phases of ZrO2, namely cubic, tetragonal and monoclinic. Cubic phase of zirconia is usually stabilized by various dopants such as yttria and magnesia. However, it has been observed that these stablizers are indeed the source failure of doped ZrO2 in both orthopaedics and in ZrO2 used in high temperature applications. Recently, the cubic zirconia was fabricated as granular media with the grain sizes less than 17nm. We examine the phase stability in zirconia nanoparticles using first principle electronic structure method. We observe considerable relaxation of lattice in the monoclinic phase near the surface. This effect combined with surface tension and possibly vacancies in nanostructures are sources of stability of cubic zirconia at nanoscale. We performed calculation of the surface tension calculations for the pure (001) surface. The uniform compressive strain is applied in the plane of the slab to find the elastic response of the system. The slab is allowed to relax in the perpendicular direction. Uniform compressive strain in the plane of the slab causes increase in the distance between Zr and O layers for (001) surface (as a solid tends to preserve the volume). For cubic it gives -0.65N/m, while for monoclinic -0.48N/m. Furthermore, the solid-gas surface tension is a fundamental physical/chemical property of a solid, which affects its wetting properties. Therefore, cubic zirconia is more suitable to design the material combining wettability, ductility and hardness.

  1. PHYSICAL PROPERTIES OF FLUORINATED PROPANE AND BUTANE DERIVATIVES AS ALTERNATIVE REFRIGERANTS

    EPA Science Inventory

    Physical property measurements are presented for 24 fluorinated propane and butane derivatives and one fluorinated ether. These measurements include melting point, boiling point, vapor pressure below the boiling point, heat of vaporization at the boiling point, critical propertie...

  2. Physical and Mechanical Properties of Niobium for SRF Science and Technology

    SciTech Connect

    Ganapati Rao Myneni

    2006-10-31

    Optimized mechanical and physical properties of high purity niobium are crucial for obtaining high performance SRF particle beam accelerator structures consistently. This paper summarizes these important material properties for both high purity polycrystalline and single crystal niobium.

  3. Summary of tank waste physical properties at the Hanford Site

    SciTech Connect

    Nguyen, Q.H.

    1994-04-01

    This report summarizes the physical parameters measured from Hanford Site tank wastes. Physical parameters were measured to determine the physical nature of the tank wastes to develop simulants and design in-tank equipment. The physical parameters were measured mostly from core samples obtained directly below tank risers. Tank waste physical parameters were collected through a database search, interviewing and selecting references from documents. This report shows the data measured from tank waste but does not describe how the analyses wee done. This report will be updated as additional data are measured or more documents are reviewed.

  4. Nanoscale growth twins in sputtered metal films

    NASA Astrophysics Data System (ADS)

    Zhang, X.; Anderoglu, O.; Hoagland, R. G.; Misra, A.

    2008-09-01

    This article reviews recent studies on the mechanical properties of sputtered copper and 330 stainless-steel films with {111} nanoscale growth twins preferentially oriented perpendicular to growth direction. The mechanisms of formation of growth twins during sputtering, unusually high strengths, and excellent thermal stability of nanotwinned structures are highlighted.

  5. Physical properties of graphene (Scientific session of the Physical Sciences Division of the Russian Academy of Sciences, 28 March 2012)

    NASA Astrophysics Data System (ADS)

    2012-11-01

    A scientific session of the Physical Sciences Division of the Russian Academy of Sciences (RAS) devoted to the "Physical properties of graphene" was held on 28 March 2012 in the conference hall of the Lebedev Physical Institute. The agenda of the session announced on the RAS Physical Sciences Division website http://www.gpad.ac.ru included the following reports: (1) Falkovsky L A (Landau Institute of Theoretical Physics, RAS, Moscow; Vereshchagin Institute of High-Pressure Physics, RAS, Moscow) "Magnetooptics of graphene"; (2) Varlamov A A (The University of Rome Tor Vergata, Italy) "Thermoelectric properties of graphene." The papers written on the basis of these reports are given below. • Magnetooptics of graphene layers, L A Falkovsky Physics-Uspekhi, 2012, Volume 55, Number 11, Pages 1140-1145 • Anomalous thermoelectric and thermomagnetic properties of graphene, A A Varlamov, A V Kavokin, I A Luk'yanchuk, S G Sharapov Physics-Uspekhi, 2012, Volume 55, Number 11, Pages 1146-1151

  6. Characterization of sheep lung lymph lipoproteins: chemical and physical properties

    SciTech Connect

    Forte, T.M.; Cross, C.E.; Gunther, R.A.; Kramer, G.C.

    1983-01-01

    The authors have determined the composition and distribution of plasma and lung lymph lipoproteins from unanesthetized ewes. Cholesterol, triglyceride, and phospholipid levels in lung lymph were 45%, 50%, and 50%, respectively, of those in plasma. Lipoproteins from both lymph and plasma were separated into two major fractions: d < 1.063 g/ml or LDL, and d 1.063-1.21 g/ml or HDL. HDL was the major lipoprotein species in the plasma and lymph. Gradients gel electrophoresis of HDL on 4-30% gels showed that, in lymph, HDL particles were shifted to larger sizes; in addition to a peak at 8.5 nm, which was similar to plasma HDL, there were two additional components of larger size, one at 9.2 nm and the other at 12 nm. Electron microscopy revealed that lymph HDL contained two new particles not seen in plasma: large, round particles, 13.6 nm diameter, and discoidal particles, 18.7 by 4.9 nm, long and short axis, respectively. Compositional analysis of lymph HDL revealed a relative enrichment in free cholesterol as well as an enrichment in apolipoprotein E. Lymph LDL on gradient gel electrophoresis was extremely heterogeneous. Several peaks were evident in the 23-30 nm size range (similar to plasma LDL), but a supplementary component at approximately 15-16 nm was also present. Whereas plasma LDL on electron microscopy contained only round particles 26 nm in diameter, lymph contained an additional, unusual particle which was close-packed, with square geometry, and was 15 nm in diameter. Changes in the physical and chemical properties of lung lymph lipoproteins suggest that these particles are metabolically modified.

  7. Physical and chemical properties of San Francisco Bay, California, 1980

    USGS Publications Warehouse

    Ota, Allan Y.; Schemel, L.E.; Hager, S.W.

    1989-01-01

    The U.S. Geological Survey conducted hydrologic investigations in both the deep water channels and the shallow-water regions of the San Francisco Bay estuarine system during 1980. Cruises were conducted regularly, usually at two-week intervals. Physical and chemical properties presented in this report include temperature , salinity, suspended particulate matter, turbidity, extinction coefficient, partial pressure of CO2, partial pressure of oxygen , dissolved organic carbon, particulate organic carbon, discrete chlorophyll a, fluorescence of photosynthetic pigments, dissolved silica, dissolved phosphate, nitrate plus nitrite, nitrite, ammonium, dissolved inorganic nitrogen, dissolved nitrogen, dissolved phosphorus, total nitrogen, and total phosphorus. Analytical methods are described. The body of data contained in this report characterizes hydrologic conditions in San Francisco Bay during a year with an average rate of freshwater inflow to the estuary. Concentrations of dissolved silica (discrete-sample) ranged from 3.8 to 310 micro-M in the northern reach of the bay, whereas the range in the southern reach was limited to 63 to 150 micro-M. Concentrations of phosphate (discrete-sample) ranged from 1.3 to 4.4 micro-M in the northern reach, which was narrow in comparison with that of 2.2 to 19.0 micro-M in the southern reach. Concentrations of nitrate plus nitrite (discrete-sample) ranged from near zero to 53 micro-M in the northern reach, and from 2.3 to 64 micro-M in the southern reach. Concentrations of nitrite (discrete-sample) were low in both reaches, exhibiting a range from nearly zero to approximately 2.3 micro-M. Concentrations of ammonium (discrete-sample) ranged from near zero to 14.2 micro-M in the northern reach, and from near zero to 8.3 micro-M in the southern reach. (USGS)

  8. Physical properties of UDF12 galaxies in cosmological simulations

    NASA Astrophysics Data System (ADS)

    Shimizu, Ikkoh; Inoue, Akio K.; Okamoto, Takashi; Yoshida, Naoki

    2014-05-01

    We have performed a large cosmological hydrodynamics simulation tailored to the deep survey with the Hubble Space Telescope made in 2012, the so-called UDF12 campaign. After making a light-cone output, we have applied the same colour-selection criteria as the UDF12 campaign to select galaxies from our simulation, and then, have examined the physical properties of them as a proxy of the real observed UDF12 galaxies at z > 7. As a result, we find that the halo mass is almost linearly proportional to the observed ultraviolet (UV) luminosity (4 × 1011M⊙ at MUV = -21). The dust attenuation and UV slope β well correlates with the observed UV luminosity, which is consistent with observations quantitatively. The star formation rate (SFR) is also linearly proportional to the stellar mass and the specific SFR shows only a weak dependence on the mass. We also find an increasing star formation history with a time-scale of ˜100 Myr in the high-z galaxies. An average metallicity weighted by the Lyman continuum luminosity reaches up to >0.1 Solar even at z ˜ 10, suggesting a rapid metal enrichment. We also expect ≥0.1 mJy at 350 GHz of the dust thermal emission from the galaxies with H160 ≤ 27, which can be detectable with the Atacama Large Millimetre-sub-millimetre Array. The galaxies selected by the UDF12 survey contribute to only 52-12 per cent of the cosmic SFR density from z ˜ 7 to z ˜ 10, respectively. The James Webb Space Telescope will push the detection fraction up to 77-72 per cent.

  9. Physical properties of luminous dust-poor quasars

    SciTech Connect

    Jun, Hyunsung David; Im, Myungshin E-mail: mim@astro.snu.ac.kr

    2013-12-20

    We identify and characterize a population of luminous, dust-poor quasars at 0 < z < 5 that is photometrically similar to objects previously found at z > 6. This class of active galactic nuclei is known to show little IR emission from dusty structure, but it is poorly understood in terms of number evolution and dependence on physical quantities. To better understand the properties of these quasars, we compile a rest-frame UV to IR library of 41,000 optically selected type 1 quasars with L {sub bol} > 10{sup 45.7} erg s{sup –1}. After fitting the broadband spectral energy distributions (SEDs) with accretion disk and dust components, we find 0.6% of our sample to be hot dust-poor, with rest-frame 2.3 μm to 0.51 μm flux density ratios of –0.5 dex or less. The dust-poor SEDs are blue in the UV-optical and weak in the mid-IR, such that their accretion disks are less obscured and the hot dust emission traces that of warm dust down to the dust-poor regime. At a given bolometric luminosity, dust-poor quasars are lower in black hole mass and higher in Eddington ratio than general luminous quasars, suggesting that they are in a rapidly growing evolutionary state in which the dust-poor phase appears as a short or rare phenomenon. The dust-poor fraction increases with redshift, and possible implications for their evolution are discussed.

  10. Visualizing Optoelectronic Processes at the Nanoscale.

    PubMed

    Mishra, Puneet; Komeda, Tadahiro

    2015-11-24

    In this issue of ACS Nano, Nienhaus et al. report the optoelectronic properties of carbon nanotube chiral junctions with nanometer resolution in the presence of strong electric fields (∼1 V/nm). Here, we provide an overview of recent studies that combine scanning tunneling microscope (STM) and laser or microwave illumination. These techniques reveal nanoscale laser- or microwave-induced phenomena utilizing the intrinsic atomic resolution of the tunneling current, and do not require substantial modification of the STM itself. The merits of atomic-scale spatial resolution and chemical sensitivity of the laser or microwave spectroscopes make these techniques useful for nanoscale characterization. PMID:26524228

  11. Phonon hydrodynamics and its applications in nanoscale heat transport

    NASA Astrophysics Data System (ADS)

    Guo, Yangyu; Wang, Moran

    2015-09-01

    Phonon hydrodynamics is an effective macroscopic method to study heat transport in dielectric solid and semiconductor. It has a clear and intuitive physical picture, transforming the abstract and ambiguous heat transport process into a concrete and evident process of phonon gas flow. Furthermore, with the aid of the abundant models and methods developed in classical hydrodynamics, phonon hydrodynamics becomes much easier to implement in comparison to the current popular approaches based on the first-principle method and kinetic theories involving complicated computations. Therefore, it is a promising tool for studying micro- and nanoscale heat transport in rapidly developing micro and nano science and technology. However, there still lacks a comprehensive account of the theoretical foundations, development and implementation of this approach. This work represents such an attempt in providing a full landscape, from physical fundamental and kinetic theory of phonons to phonon hydrodynamics in view of descriptions of phonon systems at microscopic, mesoscopic and macroscopic levels. Thus a systematical kinetic framework, summing up so far scattered theoretical models and methods in phonon hydrodynamics as individual cases, is established through a frame of a Chapman-Enskog solution to phonon Boltzmann equation. Then the basic tenets and procedures in implementing phonon hydrodynamics in nanoscale heat transport are presented through a review of its recent wide applications in modeling thermal transport properties of nanostructures. Finally, we discuss some pending questions and perspectives highlighted by a novel concept of generalized phonon hydrodynamics and possible applications in micro/nano phononics, which will shed more light on more profound understanding and credible applications of this new approach in micro- and nanoscale heat transport science.

  12. Effect of chain microstructure on physical properties of olefin copolymers

    NASA Astrophysics Data System (ADS)

    Poon, Benjamin Chunman

    The effect of chain microstructure on various physical properties was studied in polyethylene and polypropylene copolymers. Adhesion of Ziegler-Natta (ZNPE) and metallocene (mPE) catalyzed ethylene-octene copolymers to polypropylene (PP) were studied by measuring the delamination toughness G of coextruded microlayers using the T-peel test. It was found that the heterogeneous ZNPE exhibited poor adhesion to polypropylene. It was proposed that the low molecular weight, highly branched ZNPE fractions migrate to the interface to form an amorphous layer. The homogeneous mPE with the same short chain branch content showed very high G. Blending ZNPE with an mPE increased G. Atomic force microscopy revealed that blending mPE into ZNPE reduced or eliminated the amorphous interfacial layer. It was hypothesized that mPE increased miscibility of low molecular weight, highly branched fractions of ZNPE and prevented their segregation at the interface. The solid state structure and properties of homogeneous propylene-octene copolymers were examined. Based on the combined observations from melting behavior, dynamic mechanical response, morphology with primarily atomic force microscopy, X-ray diffraction, and tensile deformation, a classification scheme with 4 distinct categories is proposed. The homopolymer with 60 wt% crystallinity constitutes Type IV. It is characterized by large alpha-positive spherulite. Copolymers with up to 5 mol% octene, with at least 35 wt% crystallinity, are classified as Type III. They crystallize as alpha-positive spherulites that are smaller than the homopolymer. Both Type IV and Type III materials exhibit thermoplastic behavior. Copolymers classified as Type II have between 5 and 10 mol% octene with crystallinity in the range of 20--35%. Type II materials have smaller impinging spherulites than Type III copolymers and they are negative. The materials in this category have plastomeric behavior. Type I copolymers have more than 10 mol% octene and less

  13. The mechanical behavior of nanoscale metallic multilayers: A survey

    NASA Astrophysics Data System (ADS)

    Zhou, Q.; Xie, J. Y.; Wang, F.; Huang, P.; Xu, K. W.; Lu, T. J.

    2015-06-01

    The mechanical behavior of nanoscale metallic multilayers (NMMs) has attracted much attention from both scientific and practical views. Compared with their monolithic counterparts, the large number of interfaces existing in the NMMs dictates the unique behavior of this special class of structural composite materials. While there have been a number of reviews on the mechanical mechanism of microlaminates, the rapid development of nanotechnology brought a pressing need for an overview focusing exclusively on a property-based definition of the NMMs, especially their size-dependent microstructure and mechanical performance. This article attempts to provide a comprehensive and up-to-date review on the microstructure, mechanical property and plastic deformation physics of NMMs. We hope this review could accomplish two purposes: (1) introducing the basic concepts of scaling and dimensional analysis to scientists and engineers working on NMM systems, and (2) providing a better understanding of interface behavior and the exceptional qualities the interfaces in NMMs display at atomic scale.

  14. Tillage effects on physical properties in two soils of the Northern Great Plains

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Tillage practices profoundly affect soil physical and hydraulic properties. It is essential to select a tillage practice that sustains the soil physical properties required for successful growth of agricultural crops. We evaluated the effects of conventional (CT) and strip (ST) tillage practices on ...

  15. Change in physical properties of pine bark and switchgrass substrates over time

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Alternatives to pine bark for nursery crop substrates have been proposed, including the use of straw materials such as switchgrass. While straw substrates can be developed with suitable physical properties measured immediately after mixing, little is known about how the physical properties of straw...

  16. Mental Rolodexing: Senior Chemistry Majors' Understanding of Chemical and Physical Properties

    ERIC Educational Resources Information Center

    DeFever, Ryan S.; Bruce, Heather; Bhattacharyya, Gautam

    2015-01-01

    Using a constructivist framework, eight senior chemistry majors were interviewed twice to determine: (i) structural inferences they are able to make from chemical and physical properties; and (ii) their ability to apply their inferences and understandings of these chemical and physical properties to solve tasks on the reactivity of organic…

  17. Clustering of downhole physical property measurements at the Victoria property, Sudbury for the purpose of extracting lithological information

    NASA Astrophysics Data System (ADS)

    Mahmoodi, Omid; Smith, Richard

    2015-07-01

    Downhole density, gamma radioactivity, and magnetic susceptibility measurements in five drillholes at the Victoria property (located in the south range of the Sudbury basin) were analyzed to identify homogenous physical units. The fuzzy k-means clustering algorithm was used for unsupervised classification of the data. Four main physical units were identified in boreholes with distinct physical characteristics. Three of them were differentiated mainly based on different gamma ray and density values, and the fourth one was characterized by high magnetic susceptibility. Physical units were compared with rock types logged by geologists to determine which rock types corresponded to physical units. We found that there was a meaningful spatial and statistical correlation between physical units (characterized based on their physical property measurements) and lithological units as indicated by rock types at the Victoria property. However, not all rock types could be uniquely identified by the statistical classification, but a set of similar groups could be identified. Hence, identifying a group of rock types described by each physical unit can be used to translate physical data to/from lithological data. Alternatively, the physical log units could be used as a quality control procedure to check the geological logs, or to highlight areas where more careful logging or other investigation would be warranted.

  18. Physical, chemical, and mineral properties of the Polonnaruwa stones

    NASA Astrophysics Data System (ADS)

    Wallis, Jamie; Wickramasinghe, N. C.; Wallis, Daryl H.; Miyake, Nori; Wallis, M. K.; Hoover, Richard B.; Samaranayake, Anil; Wickramarathne, Keerthi; Oldroyd, Anthony

    2013-09-01

    We report on the physical, chemical and mineral properties of a series of stone fragments recovered from the North Central Province of Sri Lanka following a witnessed fireball event on 29 December 2012. The stones exhibit highly porous poikilitic textures comprising of isotropic silica-rich/plagioclase-like hosts. Inclusions range in size and shape from mm-sized to smaller subangular grains frequently more fractured than the surrounding host and include ilmenite, olivine (fayalitic), quartz and accessory zircon. Bulk mineral compositions include accessory cristobalite, hercynite, anorthite, wuestite, albite, anorthoclase and the high pressure olivine polymorph wadsleyite, suggesting previous endurance of a shock pressure of ~20 GPa. Further evidence of shock is confirmed by the conversion of all plagioclase to maskelynite. Here the infrared absorption spectra in the region 580 cm-1 to 380 cm-1 due to the Si-O-Si or Si-O-Al absorption band shows a partial shift in the peak at 380 cm-1 towards 480 cm-1 indicating an intermediate position between crystalline and amorphous phase. Host matrix chemical compositions vary between samples, but all are rich in SiO2. Silica-rich melts display a heterogeneous K-enrichment comparable to that reported in a range of non-terrestrial material from rare iron meteorites to LL chondritic breccias and Lunar granites. Bulk chemical compositions of plagioclase-like samples are comparable to reported data e.g. Miller Ranger 05035 (Lunar), while Si-rich samples accord well with mafic and felsic glasses reported in NWA 1664 (Howardite) as well as data for fusion crust present in a variety of meteoritic samples. Triple oxygen isotope results show Δ17O = -0.335 with δ18O (‰ rel. SMOW) values of 17.816 +/- 0.100 and compare well with those of known CI chondrites and are within the range of CI-like (Meta-C) chondrites. Rare earth elemental abundances show a profound Europium anomaly of between 0.7 and 0.9 ppm while CI normalized REE

  19. Physical and orbital properties of β Pictoris b

    NASA Astrophysics Data System (ADS)

    Bonnefoy, M.; Marleau, G.-D.; Galicher, R.; Beust, H.; Lagrange, A.-M.; Baudino, J.-L.; Chauvin, G.; Borgniet, S.; Meunier, N.; Rameau, J.; Boccaletti, A.; Cumming, A.; Helling, C.; Homeier, D.; Allard, F.; Delorme, P.

    2014-07-01

    The intermediate-mass star β Pictoris is known to be surrounded by a structured edge-on debris disk within which a gas giant planet was discovered orbiting at 8-10 AU. The physical properties of β Pic b were previously inferred from broad- and narrow-band 0.9-4.8 μm photometry. We used commissioning data of the Gemini Planet Imager (GPI) to obtain new astrometry and a low-resolution (R ~ 35-39) J-band (1.12-1.35 μm) spectrum of the planet. We find that the planet has passed the quadrature. We constrain its semi-major axis to ≤10 AU (90% prob.) with a peak at 8.9+0.4-0.6 AU. The joint fit of the planet astrometry and the most recent radial velocity measurements of the star yields a planet dynamical mass lower than 20 MJup (≥96% prob.). The extracted spectrum of β Pic b is similar to those of young L1-1.5+1 dwarfs. We used the spectral type estimate to revise the planet luminosity to log (L/L⊙) = -3.90 ± 0.07. The 0.9-4.8 μm photometry and spectrum are reproduced for Teff = 1650 ± 150 K and a log g ≤ 4.7 dex by 12 grids of PHOENIX-based and LESIA atmospheric models. For the most recent system age estimate (21 ± 4 Myr), the bolometric luminosity and the constraints on the dynamical mass of β Pic b are only reproduced by warm- and hot-start tracks with initial entropies Si> 10.5 kB/baryon. These initial conditions may result from an inefficient accretion shock and/or a planetesimal density at formation higher than in the classical core-accretion model. Considering a younger age for the system or a conservative formation time for β Pic b does not change these conclusions. Appendices are available in electronic form at http://www.aanda.org

  20. Physical properties of the Saturn's rings with the opposition effect.

    NASA Astrophysics Data System (ADS)

    Deau, E.

    2012-04-01

    We use the Cassini/ISS images from the early prime mission to build lit phase curves data from 0.01 degrees to 155 degrees at a solar elevation of 23-20 degrees. All the main rings exhibit on their phase curves a prominent surge at small phase angles. We use various opposition effect models to explain the opposition surge of the rings, including the coherent backscattering, the shadow hiding and a combination of the two (Kawata & Irvine 1974 In: Exploration of the planetary system Book p441; Shkuratov et al. 1999, Icarus, 141, p132; Poulet et al. 2002 Icarus, 158, p224 ; Hapke et al. 2002 Icarus, 157, p523). Our results show that either the coherent backscattering alone or a combination of the shadow hiding and the coherent backscattering can explain the observations providing physical properties (albedo, filling factor, grain size) consistent with previous other studies. However, they disagree with the most recent work of Degiorgio et al. 2011 (EPSC-DPS Abstract #732). We think that their attempt to use the shadow hiding alone lead to unrealistic values of the filling factor of the ring particles layer. For example they found 10^-3 in one of the thickest regions of the C ring (a plateau at R=88439km with an optical depth tau=0.22). We totally disagree with their conclusions stating that these values are consistent for the C ring plateaux and did not found any references that are consistent with theirs, as they claimed. We believe that their unrealistic values originated from the assumptions of the models they used (Kawata & Irvine and Hapke), which are basically an uniform size distribution. Any model using an uniform size distribution force the medium to be very diluted to reproduce the opposition surge. Our modeling that uses a power law size distribution provides realistic values. All these results have been already published previously (http://adsabs.harvard.edu/abs/2007PhDT........25D) and are summarized in a forthcoming manuscript submitted to publication so

  1. Optical Properties of Materials in an Undergraduate Physics Curriculum

    NASA Astrophysics Data System (ADS)

    Blanco, Julio R.

    2006-03-01

    The need to introduce physics undergraduates to non-traditional subjects is ever increasing due to the job opportunities in interdisciplinary fields. The traditional upper-level curricula after the standard sequence in introductory calculus-based physics is challenging to many students. Adding more elective requirements is not in vogue with university administrators that must deal with a large influx of students with fewer resources. Experimental physics lends itself well to introduce students to interdisciplinary concepts. At California State University Northridge (CSUN), we have introduced modules in experimental physics to meet this need. All juniors and seniors are required to take two units of experimental physics per semester, a total of eight units. An experimental unit represents three contact hours per week. Each two units consist of two modules, each lasting seven and a half weeks, six hours per week. One of these modules exposes the students to thin film deposition by sputtering, imaging by scanning electron microscopy, and optical characterization using scanning ellipsometry. This early exposure to interdisciplinary applied physics motivates students and identifies difficulties with fundamental concepts.

  2. Nanoscale β-nuclear magnetic resonance depth imaging of topological insulators

    PubMed Central

    Koumoulis, Dimitrios; Morris, Gerald D.; He, Liang; Kou, Xufeng; King, Danny; Wang, Dong; Hossain, Masrur D.; Wang, Kang L.; Fiete, Gregory A.; Kanatzidis, Mercouri G.; Bouchard, Louis-S.

    2015-01-01

    Considerable evidence suggests that variations in the properties of topological insulators (TIs) at the nanoscale and at interfaces can strongly affect the physics of topological materials. Therefore, a detailed understanding of surface states and interface coupling is crucial to the search for and applications of new topological phases of matter. Currently, no methods can provide depth profiling near surfaces or at interfaces of topologically inequivalent materials. Such a method could advance the study of interactions. Herein, we present a noninvasive depth-profiling technique based on β-detected NMR (β-NMR) spectroscopy of radioactive 8Li+ ions that can provide “one-dimensional imaging” in films of fixed thickness and generates nanoscale views of the electronic wavefunctions and magnetic order at topological surfaces and interfaces. By mapping the 8Li nuclear resonance near the surface and 10-nm deep into the bulk of pure and Cr-doped bismuth antimony telluride films, we provide signatures related to the TI properties and their topological nontrivial characteristics that affect the electron–nuclear hyperfine field, the metallic shift, and magnetic order. These nanoscale variations in β-NMR parameters reflect the unconventional properties of the topological materials under study, and understanding the role of heterogeneities is expected to lead to the discovery of novel phenomena involving quantum materials. PMID:26124141

  3. Nanoscale β-nuclear magnetic resonance depth imaging of topological insulators

    NASA Astrophysics Data System (ADS)

    Koumoulis, Dimitrios; Morris, Gerald D.; He, Liang; Kou, Xufeng; King, Danny; Wang, Dong; Hossain, Masrur D.; Wang, Kang L.; Fiete, Gregory A.; Kanatzidis, Mercouri G.; Bouchard, Louis-S.

    2015-07-01

    Considerable evidence suggests that variations in the properties of topological insulators (TIs) at the nanoscale and at interfaces can strongly affect the physics of topological materials. Therefore, a detailed understanding of surface states and interface coupling is crucial to the search for and applications of new topological phases of matter. Currently, no methods can provide depth profiling near surfaces or at interfaces of topologically inequivalent materials. Such a method could advance the study of interactions. Herein, we present a noninvasive depth-profiling technique based on β-detected NMR (β-NMR) spectroscopy of radioactive 8Li+ ions that can provide "one-dimensional imaging" in films of fixed thickness and generates nanoscale views of the electronic wavefunctions and magnetic order at topological surfaces and interfaces. By mapping the 8Li nuclear resonance near the surface and 10-nm deep into the bulk of pure and Cr-doped bismuth antimony telluride films, we provide signatures related to the TI properties and their topological nontrivial characteristics that affect the electron-nuclear hyperfine field, the metallic shift, and magnetic order. These nanoscale variations in β-NMR parameters reflect the unconventional properties of the topological materials under study, and understanding the role of heterogeneities is expected to lead to the discovery of novel phenomena involving quantum materials.

  4. Nanoscale β-nuclear magnetic resonance depth imaging of topological insulators.

    PubMed

    Koumoulis, Dimitrios; Morris, Gerald D; He, Liang; Kou, Xufeng; King, Danny; Wang, Dong; Hossain, Masrur D; Wang, Kang L; Fiete, Gregory A; Kanatzidis, Mercouri G; Bouchard, Louis-S

    2015-07-14

    Considerable evidence suggests that variations in the properties of topological insulators (TIs) at the nanoscale and at interfaces can strongly affect the physics of topological materials. Therefore, a detailed understanding of surface states and interface coupling is crucial to the search for and applications of new topological phases of matter. Currently, no methods can provide depth profiling near surfaces or at interfaces of topologically inequivalent materials. Such a method could advance the study of interactions. Herein, we present a noninvasive depth-profiling technique based on β-detected NMR (β-NMR) spectroscopy of radioactive (8)Li(+) ions that can provide "one-dimensional imaging" in films of fixed thickness and generates nanoscale views of the electronic wavefunctions and magnetic order at topological surfaces and interfaces. By mapping the (8)Li nuclear resonance near the surface and 10-nm deep into the bulk of pure and Cr-doped bismuth antimony telluride films, we provide signatures related to the TI properties and their topological nontrivial characteristics that affect the electron-nuclear hyperfine field, the metallic shift, and magnetic order. These nanoscale variations in β-NMR parameters reflect the unconventional properties of the topological materials under study, and understanding the role of heterogeneities is expected to lead to the discovery of novel phenomena involving quantum materials. PMID:26124141

  5. Physical properties of asteroid dust bands and their sources

    NASA Astrophysics Data System (ADS)

    Nesvorný, David; Vokrouhlický, David; Bottke, William F.; Sykes, Mark

    2006-03-01

    Disruptive collisions in the main belt can liberate fragments from parent bodies ranging in size from several micrometers to tens of kilometers in diameter. These debris bodies group at initially similar orbital locations. Most asteroid-sized fragments remain at these locations and are presently observed as asteroid families. Small debris particles are quickly removed by Poynting-Robertson drag or comminution but their populations are replenished in the source locations by collisional cascade. Observations from the Infrared Astronomical Satellite (IRAS) showed that particles from particular families have thermal radiation signatures that appear as band pairs of infrared emission at roughly constant latitudes both above and below the Solar System plane. Here we apply a new physical model capable of linking the IRAS dust bands to families with characteristic inclinations. We use our results to constrain the physical properties of IRAS dust bands and their source families. Our results indicate that two prominent IRAS bands at inclinations ≈2.1° and ≈9.3° are byproducts of recent asteroid disruption events. The former is associated with a disruption of a ≈30-km asteroid occurring 5.8 Myr ago; this event gave birth to the Karin family. The latter came from the breakup of a large >100-km-diameter asteroid 8.3 Myr ago that produced the Veritas family. Using an N-body code, we tracked the dynamical evolution of ≈10 6 particles, 1 μm to 1 cm in diameter, from both families. We then used these results in a Monte Carlo code to determine how small particles from each population undergo collisional evolution. By computing the thermal emission of particles, we were able to compare our results with IRAS observations. Our best-fit model results suggest the Karin and Veritas family particles contribute by 5-9% in 10-60-μm wavelengths to the zodiacal cloud's brightness within 50° latitudes around the ecliptic, and by 9-15% within 10° latitudes. The high brightness of

  6. Sensing at the nanoscale

    NASA Astrophysics Data System (ADS)

    Demming, Anna; Hierold, Christofer

    2013-11-01

    The merits of nanostructures in sensing may seem obvious, yet playing these attributes to their maximum advantage can be a work of genius. As fast as sensing technology is improving, expectations are growing, with demands for cheaper devices with higher sensitivities and an ever increasing range of functionalities and compatibilities. At the same time tough scientific challenges like low power operation, noise and low selectivity are keeping researchers busy. This special issue on sensing at the nanoscale with guest editor Christofer Hierold from ETH Zurich features some of the latest developments in sensing research pushing at the limits of current capabilities. Cheap and easy fabrication is a top priority. Among the most popular nanomaterials in sensing are ZnO nanowires and in this issue Dario Zappa and colleagues at Brescia University in Italy simplify an already cheap and efficient synthesis method, demonstrating ZnO nanowire fabrication directly onto silicon substrates [1]. Meanwhile Nicolae Barson and colleagues in Germany point out the advantages of flame spray pyrolysis fabrication in a topical review [2] and, maximizing on existing resources, researchers in Denmark and Taiwan report cantilever sensing using a US20 commercial DVD-ROM optical pickup unit as the readout source [3]. The sensor is designed to detect physiological concentrations of soluble urokinase plasminogen activator receptor, a protein associated with inflammation due to HIV, cancer and other infectious diseases. With their extreme properties carbon nanostructures feature prominently in the issue, including the demonstration of a versatile and flexible carbon nanotube strain sensor [4] and a graphene charge sensor with sensitivities of the order of 1.3 × 10-3 e Hz-1/2 [5]. The issue of patterning for sensing devices is also tackled by researchers in the US who demonstrate a novel approach for multicomponent pattering metal/metal oxide nanoparticles on graphene [6]. Changes in electrical

  7. Lunar physical properties from analysis of magnetometer data

    NASA Technical Reports Server (NTRS)

    Daily, W. D.

    1979-01-01

    The electromagnetic properties of the lunar interior are discussed with emphasis on (1) bulk, crustal, and local anomalous conductivity; (2) bulk magnetic permeability measurements, iron abundance estimates, and core size limits; (3) lunar ionosphere and atmosphere; and (4) crustal magnetic remanence: scale size measurements and constraints on remanence origin. Appendices treat the phase relationship between the energetic particle flux modulation and current disc penetrations in the Jovian magnetosphere (Pioneer 10 inbound) theories for the origin of lunar magnetism; electrical conductivity anomalies associated with circular lunar maria; electromagnetic properties of the Moon; Mare Serenitatis conductivity anomaly detected by Apollo 16 and Lunokhod 2 magnetometers; and lunar properties from magnetometer data: effects of data errors.

  8. Nanoscale Characterization of Mock Explosive Materials Using Advanced Atomic Force Microscopy Methods

    NASA Astrophysics Data System (ADS)

    Xu, Xin; Mares, Jesus; Groven, Lori J.; Son, Steven F.; Reifenberger, Ronald G.; Raman, Arvind

    2015-01-01

    Most explosives are micro- and nanoscale composite material systems consisting of energetic crystals, amorphous particles, binders, and additives whose response to mechanical, thermal, or electromagnetic insults is often controlled by submicrometer-scale heterogeneities and interfaces. Several advanced dynamic atomic force microscopy (AFM) techniques, including phase imaging, force volume mode, and Kelvin probe force microscopy with resonance enhancement for dielectric property mapping, have been used to map the local physical properties of mock explosive materials systems, allowing the identification of submicrometer heterogeneities in electrical and mechanical properties that could lead to the formation of hotspots under electromagnetic or mechanical stimuli. The physical interpretation of the property maps and the methods of image formation are presented. Possible interpretations of the results and future applications to energetic material systems are also discussed.

  9. Selection and Physical Properties of High-redshift Galaxies

    NASA Astrophysics Data System (ADS)

    Fang, G. W.

    2014-09-01

    Extremely Red Objects (EROs) and BzKs continue to attract considerable interest. It has been suggested that they may be the direct progenitors of present-day massive E/S0 galaxies, and can provide crucial constraints on the current galaxy formation and evolution models. Therefore, the key question is to measure the relative fraction of OGs (old galaxies) and DGs (young, and dusty starburst galaxies) in the sample of EROs. Many groups have been currently investigating the fractions of these two ERO populations using a variety of observational approaches, but the fraction of OGs and DGs from different surveys is different. In the meantime, a number of observations suggest that the epoch of z˜2 also plays an important role in galaxy formation and evolution for various reasons: the cosmic star formation rate density (SFRD) begins to drop at z˜2 from a flat plateau at higher redshifts; the morphological type mix of field galaxies changes remarkably at z˜2; the number density of QSOs has a peak at z˜2; and about 50% to 70% of the stellar mass assembly of galaxies took place in the redshift range 1physical properties of passive and star-forming galaxies at z˜2 in the AEGIS field, and (3) the mid-infrared spectroscopy and multi-wavelength study of ultraluminous infrared galaxies (ULIRGs) at z˜2 in the AEGIS field. Chapter 1 gives a brief review on the research progresses of EROs at z˜1, BzKs at z˜2, and ULIRGs at z˜2, respectively. In Chapter 2 we present a quantitative study of the classification of EROs in the UDF and COSMOS field. Our sample includes 5264 (COSMOS, K_{Vega} ≤19.2) and 24 EROs (UDF, K_{Vega}≤22.0) with (i-K)_{AB}≥2.45. Using the fitting method of spectral energy distribution (SED), [3.6]-[8.0] color, and the nonparametric measures of galaxy morphology, we classify EROs into two classes: DGs and OGs. We find

  10. Nanoscale precipitation in hot rolled sheet steel

    NASA Astrophysics Data System (ADS)

    Sun, Jun

    Some newer hot rolled high strength low alloy (HSLA) steels with a single phase ferrite matrix have obtained substantial strengthening from nanoscale precipitation. These HSLA are reported to have a good combination of strength, ductility and hole-expansion ability. In the current work, Gleeble ® 3500 torsion testing was employed to simulate the hot rolling process with varying run-out table cooling rates and coiling temperatures on five microalloyed steels with additions of Ti, Nb, Mo, Cr and V, to investigate the effects of microalloy additions and processing conditions on microstructures as well as mechanical properties. Subsized tensile specimens obtained from as-twisted torsion samples were used to evaluate mechanical properties. The precipitation states of the five steels with different processing conditions were characterized using extraction replica TEM. Comparison of microstructures and mechanical properties was discussed. Characterization of the microstructure via light optical microscopy showed the matrix microstructure was mainly influenced by coiling temperature, which indicates that the transformation from austenite to ferrite occurred during the coiling period. A higher Ti content was shown to reduce the second constituent fractions. Investigation of carbon extraction replica specimens via TEM revealed the presence of nanoscale precipitation. Extensive nanoscale precipitation was observed in most of the specimens having a polygonal ferrite matrix, while in the granular bainite/ferrite microstructure at lower temperatures, fewer microalloy carbides were present. The specimens with polygonal ferrite had similar or higher yield strength than the specimens with granular bainite microstructure, which suggests the effectiveness of precipitation strengthening from extensive nanoscale precipitates. In the Nb-Mo steel, more significant strengthening due to grain refinement was evident. Yield strength values were less than reported for JFE's "NANOHITEN

  11. Physical Sensing of Surface Properties by Microswimmers – Directing Bacterial Motion via Wall Slip

    PubMed Central

    Hu, Jinglei; Wysocki, Adam; Winkler, Roland G.; Gompper, Gerhard

    2015-01-01

    Bacteria such as Escherichia coli swim along circular trajectories adjacent to surfaces. Thereby, the orientation (clockwise, counterclockwise) and the curvature depend on the surface properties. We employ mesoscale hydrodynamic simulations of a mechano-elastic model of E. coli, with a spherocylindrical body propelled by a bundle of rotating helical flagella, to study quantitatively the curvature of the appearing circular trajectories. We demonstrate that the cell is sensitive to nanoscale changes in the surface slip length. The results are employed to propose a novel approach to directing bacterial motion on striped surfaces with different slip lengths, which implies a transformation of the circular motion into a snaking motion along the stripe boundaries. The feasibility of this approach is demonstrated by a simulation of active Brownian rods, which also reveals a dependence of directional motion on the stripe width. PMID:25993019

  12. Physical Sensing of Surface Properties by Microswimmers--Directing Bacterial Motion via Wall Slip.

    PubMed

    Hu, Jinglei; Wysocki, Adam; Winkler, Roland G; Gompper, Gerhard

    2015-01-01

    Bacteria such as Escherichia coli swim along circular trajectories adjacent to surfaces. Thereby, the orientation (clockwise, counterclockwise) and the curvature depend on the surface properties. We employ mesoscale hydrodynamic simulations of a mechano-elastic model of E. coli, with a spherocylindrical body propelled by a bundle of rotating helical flagella, to study quantitatively the curvature of the appearing circular trajectories. We demonstrate that the cell is sensitive to nanoscale changes in the surface slip length. The results are employed to propose a novel approach to directing bacterial motion on striped surfaces with different slip lengths, which implies a transformation of the circular motion into a snaking motion along the stripe boundaries. The feasibility of this approach is demonstrated by a simulation of active Brownian rods, which also reveals a dependence of directional motion on the stripe width. PMID:25993019

  13. Effect of irrigation and nutrient on physical properties of safflower seeds

    NASA Astrophysics Data System (ADS)

    Feyzollahzadeh, Maziar; ModaresMotlagh, Asaad; Nikbakht, Ali M.

    2014-03-01

    The effect of irrigation and nutrient treatments on physical properties of safflower seeds was investigated. Physical properties of safflower seeds were determined at a moisture content of 7% w.b. The parameters determined at different treatments were: size, geometric mean diameter, sphericity, surface area, mass, volume, bulk and true densities, porosity, and static and dynamic coefficient of friction. The results showed a better effect of the use of organic fertilizers in comparison with chemical ones. The results showed that nutrient and irrigation treatments had a significant effect on most of the physical properties of safflower seeds at p<0.01.

  14. Physical Properties of Various Materials Relevant to Granular Flow

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Because of the ubiquitous nature of granular materials, ranging from natural avalanches to industrial storage and processing operations, interest in quantifying and predicting the dynamics of granular flow continues to increase. The objective of this study was to investigate various physical proper...

  15. Physical properties of Ce-TZP at cryogenic temperature

    NASA Astrophysics Data System (ADS)

    Han, Y. M.; Chen, Z.; Zhou, M.; Huang, R. J.; Huang, C. J.; Li, L. F.

    2014-01-01

    Electrical insulators, which are used to insulate cryogenic supply lines and conductor windings, are critical units in superconducting TOKAMAK magnets. Electrical insulators used in superconducting magnets fall into axial and radial insulators. These insulators can be made from glass ribbon epoxy densification and have been used in the Experiment Advanced Superconducting Tokamak (EAST). The properties of Ce-TZP can satisfy the requirement of electrical insulators. In this paper, thermal conductivity, mechanical properties and coefficient of thermal expansion of Ce-TZP have been investigated at cryogenic temperatures. Results indicate that the Ce-TZP shows better properties than epoxy and it demonstrates that the Ce-TZP can be used as insulation material in superconducting magnets.

  16. Polymer crystallization in thin films: morphology and physical properties

    NASA Astrophysics Data System (ADS)

    Kelly, Giovanni; Albert, Julie

    Polymer crystallization has been studied both computationally and experimentally for decades, elucidating many of the mysteries surrounding crystallization kinetics and thermodynamics. However, many unanswered questions remain pertaining to the relationships between crystallization phenomena and material properties needed for specific applications that range from drug delivery and tissue engineering to optical devices and mechanically robust membranes. One of the especially interesting facets of polymer crystallization is the behavior observed when these long chain molecules are spatially confined in thin and ultrathin films. Confined geometry leads to chain configurations, and therefore thermal, mechanical, and optical properties, sometimes far removed from reported bulk values. This project aims to study the phenomena exhibited by linear semi-crystalline polymers in thin films as well as the way in which blending with homopolymers, block copolymers, and novel polymer chain architectures affect morphology, biodegradation, optical, thermal, and mechanical properties.

  17. Nanoscale origins of nonlinear behavior in ferroic thin-films

    SciTech Connect

    Vasudevan, Rama K; Okatan, M. B.; Duan, C.; Funakubo, Hiroshi; Kumar, Amit; Jesse, Stephen; Chen, Long-Qing; Kalinin, Sergei V; Nagarajan, Valanoor

    2012-01-01

    The nonlinear response of a ferroic to an applied stimulus (e.g. electric field, mechanical stress) is a fundamental characteristic that underpins a number of technologically significant applications[1-3]. It is also the driving feature in numerous physical phenomena, such as interfacial motion[4,5], spin glasses[6], relaxors[7] and phase transitions[8]. In particular, nonlinearity associated with minor hysteresis loops is an extremely useful avenue to explore energy dissipation and losses in such systems. This knowledge is necessary for the design of future materials with enhanced low-field properties. Quantitatively, the macroscopic nonlinear response of ferroic systems at low to mid-range amplitudes of driving fields is given by the phenomenological Rayleigh law[9], first conceived in 1887 for magnetic materials. Yet, the applicability of the Rayleigh law at small length scales has not been extensively studied. Here, we show using a combination of scanning probe techniques and phase field modeling, that nanoscale response appears to follow a non-Rayleigh regime. However, through statistical analysis, we find that a distribution in the individual responses can lead to directly to Rayleigh-like behavior of the strain on a macroscale. The studies shed light on the nanoscale origins of nonlinear behavior in disordered ferroics.

  18. Symposium GC: Nanoscale Charge Transport in Excitonic Solar Cells

    SciTech Connect

    Bommisetty, Venkat

    2011-06-23

    This paper provides a summary only and table of contents of the sessions. Excitonic solar cells, including all-organic, hybrid organic-inorganic and dye-sensitized solar cells (DSSCs), offer strong potential for inexpensive and large-area solar energy conversion. Unlike traditional inorganic semiconductor solar cells, where all the charge generation and collection processes are well understood, these excitonic solar cells contain extremely disordered structures with complex interfaces which results in large variations in nanoscale electronic properties and has a strong influence on carrier generation, transport, dissociation and collection. Detailed understanding of these processes is important for fabrication of highly efficient solar cells. Efforts to improve efficiency are underway at a large number of research groups throughout the world focused on inorganic and organic semiconductors, photonics, photophysics, charge transport, nanoscience, ultrafast spectroscopy, photonics, semiconductor processing, device physics, device structures, interface structure etc. Rapid progress in this multidisciplinary area requires strong synergetic efforts among researchers from diverse backgrounds. Such effort can lead to novel methods for development of new materials with improved photon harvesting and interfacial treatments for improved carrier transport, process optimization to yield ordered nanoscale morphologies with well defined electronic structures.

  19. Effective Interaction Potentials and Physical Properties of Complex Plasmas

    SciTech Connect

    Ramazanov, T. S.; Dzhumagulova, K. N.; Gabdullin, M. T.; Omarbakiyeva, Y. A.

    2009-11-10

    Microscopic, thermodynamic and transport properties of complex plasmas are investigated on the basis of effective potentials of interparticle interaction. These potentials take into account correlation effects and quantum-mechanical diffraction. Plasma composition, thermodynamic functions of hydrogen and helium plasmas are obtained for a wide region of coupling parameter. Collision processes in partially ionized plasma are considered; some kinetic characteristics such as phase shift, scattering cross section, bremsstrahlung cross section and absorption coefficient are investigated. Dynamic and transport properties of dusty plasma are studied by computer simulation method of the Langevin dynamics.

  20. Integrating Condensed Matter Physics into a Liberal Arts Physics Curriculum

    NASA Astrophysics Data System (ADS)

    Collett, Jeffrey

    2008-03-01

    The emergence of nanoscale science into the popular consciousness presents an opportunity to attract and retain future condensed matter scientists. We inject nanoscale physics into recruiting activities and into the introductory and the core portions of the curriculum. Laboratory involvement and research opportunity play important roles in maintaining student engagement. We use inexpensive scanning tunneling (STM) and atomic force (AFM) microscopes to introduce students to nanoscale structure early in their college careers. Although the physics of tip-surface interactions is sophisticated, the resulting images can be interpreted intuitively. We use the STM in introductory modern physics to explore quantum tunneling and the properties of electrons at surfaces. An interdisciplinary course in nanoscience and nanotechnology course team-taught with chemists looks at nanoscale phenomena in physics, chemistry, and biology. Core quantum and statistical physics courses look at effects of quantum mechanics and quantum statistics in degenerate systems. An upper level solid-state physics course takes up traditional condensed matter topics from a structural perspective by beginning with a study of both elastic and inelastic scattering of x-rays from crystalline solids and liquid crystals. Students encounter reciprocal space concepts through the analysis of laboratory scattering data and by the development of the scattering theory. The course then examines the importance of scattering processes in band structure and in electrical and thermal conduction. A segment of the course is devoted to surface physics and nanostructures where we explore the effects of restricting particles to two-dimensional surfaces, one-dimensional wires, and zero-dimensional quantum dots.

  1. Order-of-magnitude physics of neutron stars. Estimating their properties from first principles

    NASA Astrophysics Data System (ADS)

    Reisenegger, Andreas; Zepeda, Felipe S.

    2016-03-01

    We use basic physics and simple mathematics accessible to advanced undergraduate students to estimate the main properties of neutron stars. We set the stage and introduce relevant concepts by discussing the properties of "everyday" matter on Earth, degenerate Fermi gases, white dwarfs, and scaling relations of stellar properties with polytropic equations of state. Then, we discuss various physical ingredients relevant for neutron stars and how they can be combined in order to obtain a couple of different simple estimates of their maximum mass, beyond which they would collapse, turning into black holes. Finally, we use the basic structural parameters of neutron stars to briefly discuss their rotational and electromagnetic properties.

  2. Physical properties of unacetylated chromatin as examined by magnetic tweezers

    NASA Astrophysics Data System (ADS)

    McGill, Kerry; Dunlap, David; Lucchesi, John

    2011-10-01

    As the source of genetic material, DNA is involved in a variety of biological processes like transcription, cell replication, and more. In these processes, DNA is manipulated into different structures and is subjected to different levels of physical force on a molecular scale. When tension is applied to one hierarchical structure called chromatin, it appears to behave like a Hookian spring. The base component of chromatin is a nucleosome, which is constructed when DNA coils around octamers of histone proteins. The histones can become acetylated---a chemical process in which an acetyl functional group attaches to amino acids of the histones, often lysines. Acetylation may loosen chromatin's coils and therefore lower the amount of tension required to stretch the chromatin. Comparing the levels of tension required to stretch acetylated chromatin could reveal, directly, physical differences in the chromatin fiber that bear ion the function of the DNA molecule. Work presented will be the investigation of unacetylated chromatin.

  3. PHYSICAL PROPERTIES OF EXTRUDED AND INJECTION MOLDED CORN GLUTEN MEAL

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study was performed to investigate the compounding of corn gluten meal (CGM) and decanoic acid and to evaluate their mechanical properties. The mixture of CGM and 30% decanoic acid was compounded in a twin screw extruder, followed by injection molding. Scanning electron microscopy (SEM), tens...

  4. Physical properties of epoxy resin/titanium dioxide nanocomposites

    SciTech Connect

    Polyzos, Georgios; Tuncer, Enis; Sauers, Isidor; More, Karren Leslie

    2011-01-01

    A polymeric nanocomposite system (nanodielectric) was fabricated, and its mechanical properties were determined. The fabricated nanocomposite was composed of low concentrations of monodispersed titanium dioxide (TiO{sub 2}) nanoparticles and an epoxy resin specially designed for cryogenic applications. The monodispersed TiO{sub 2} nanoparticles were synthesized in an aqueous solution of titanium chloride and polyethylene glycol and subsequently dispersed in a commercial-grade epoxy resin (Araldite{reg_sign} 5808). Nanocomposite thin sheets were prepared at several weight fractions of TiO{sub 2}. The morphology of the composites, determined by transmission electron microscopy, showed that the nanoparticles aggregated to form particle clusters. The influence of thermal processing and the effect of filler dispersion on the structure-property relationships were identified by differential scanning calorimetry and dynamic mechanical analysis at a broad range of temperatures. The effect of the aggregates on the electrical insulation properties was determined by dielectric breakdown measurements. The optical properties of the nanocomposites and their potential use as filters in the ultraviolet-visible (UV-vis) range were determined by UV-vis spectroscopy.

  5. PHYSICAL AND ENGINEERING PROPERTIES OF HAZARDOUS INDUSTRIAL WASTES AND SLUDGES

    EPA Science Inventory

    This report presents the results of a laboratory testing program to investigate the properties of raw and chemically fixed hazardous industrial wastes and flue gas desulfurization (FGD) sludges. Specimens of raw and fixed sludges were subjected to a variety of tests commonly used...

  6. Program Gives Data On Physical Properties Of Hydrogen

    NASA Technical Reports Server (NTRS)

    Roder, H. M.; Mccarty, R. D.; Hall, W. J.

    1994-01-01

    TAB II computer program provides values of thermodynamic and transport properties of hydrogen in useful format. Also, provides values for equilibrium hydrogen and para-hydrogen. Program fast, moderately accurate, and operates over wide ranges of input variables. Written in FORTRAN 77.

  7. Synthesis and physical properties of new estolide esters

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Vegetable oil-based oils usually fail to meet the rigorous demands of industrial lubricants by not having acceptable low temperature properties, pour point (PP) and/or cloud point (CP). The oleic estolide was esterified with a series of 16 different alcohols that were either branched or straight-cha...

  8. Physical property measurements of doped cesium iodide crystals

    NASA Technical Reports Server (NTRS)

    Synder, R. S.; Clotfelter, W. N.

    1974-01-01

    Mechanical and thermal property values are reported for crystalline cesium iodide doped with sodium and thallium. Young's modulus, bulk modulus, shear modulus, and Poisson's ratio were obtained from ultrasonic measurements. Young's modulus and the samples' elastic and plastic behavior were also measured under tension and compression. Thermal expansion and thermal conductivity were the temperature dependent measurements that were made.

  9. 40 CFR 716.50 - Reporting physical and chemical properties.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... they investigated one or more of the following properties: (a) Water solubility. (b) Adsorption/desorption on particulate surfaces, e.g., soil. (c) Vapor pressure. (d) Octanol/water partition coefficient. (e) Density/relative density (specific gravity). (f) Particle size distribution for insoluble...

  10. Synthesis and physical properties of isostearic acids and their esters

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Saturated branched-chain fatty acids (sbc-FAs) are found as minor constituents in several natural fats and oils. Sbc-FAs are of interest since they have lower melting points than their linear counterparts and exhibit good oxidative stability; properties that make them ideally suited in a number of ...

  11. Statistical physics ""Beyond equilibrium

    SciTech Connect

    Ecke, Robert E

    2009-01-01

    The scientific challenges of the 21st century will increasingly involve competing interactions, geometric frustration, spatial and temporal intrinsic inhomogeneity, nanoscale structures, and interactions spanning many scales. We will focus on a broad class of emerging problems that will require new tools in non-equilibrium statistical physics and that will find application in new material functionality, in predicting complex spatial dynamics, and in understanding novel states of matter. Our work will encompass materials under extreme conditions involving elastic/plastic deformation, competing interactions, intrinsic inhomogeneity, frustration in condensed matter systems, scaling phenomena in disordered materials from glasses to granular matter, quantum chemistry applied to nano-scale materials, soft-matter materials, and spatio-temporal properties of both ordinary and complex fluids.

  12. Simulations of Metallic Nanoscale Structures

    NASA Astrophysics Data System (ADS)

    Jacobsen, Karsten W.

    2003-03-01

    Density-functional-theory calculations can be used to understand and predict materials properties based on their nanoscale composition and structure. In combination with efficient search algorithms DFT can furthermore be applied in the nanoscale design of optimized materials. The first part of the talk will focus on two different types of nanostructures with an interesting interplay between chemical activity and conducting states. MoS2 nanoclusters are known for their catalyzing effect in the hydrodesulfurization process which removes sulfur-containing molecules from oil products. MoS2 is a layered material which is insulating. However, DFT calculations indicates the exsistence of metallic states at some of the edges of MoS2 nanoclusters, and the calculations show that the conducting states are not passivated by for example the presence of hydrogen gas. The edge states may play an important role for the chemical activity of MoS_2. Metallic nanocontacts can be formed during the breaking of a piece of metal, and atomically thin structures with conductance of only a single quantum unit may be formed. Such open metallic structures are chemically very active and susceptible to restructuring through interactions with molecular gases. DFT calculations show for example that atomically thin gold wires may incorporate oxygen atoms forming a new type of metallic nanowire. Adsorbates like hydrogen may also affect the conductance. In the last part of the talk I shall discuss the possibilities for designing alloys with optimal mechanical properties based on a combination of DFT calculations with genetic search algorithms. Simulaneous optimization of several parameters (stability, price, compressibility) is addressed through the determination of Pareto optimal alloy compositions within a large database of more than 64000 alloys.

  13. PREDICTION OF CHEMICAL REACTIVITY PARAMETERS AND PHYSICAL PROPERTIES OF ORGANIC COMPOUNDS FROM MOLECULAR STRUCTURE USING SPARC

    EPA Science Inventory

    The computer program SPARC (SPARC Performs Automated Reasoning in Chemistry) has been under development for several years to estimate physical properties and chemical reactivity parameters of organic compounds strictly from molecular structure. SPARC uses computational algorithms...

  14. PHYSICAL PROPERTIES AND LEACH TESTING OF SOLIDIFIED/STABILIZED INDUSTRIAL WASTES

    EPA Science Inventory

    Physical property and leaching tests were conducted to assess the engineering characteristics and pollution potential of five industrial wastes. Four solidification/stabilization processes which are under development or commercially available and represent different containment p...

  15. ESTIMATION OF PHYSICAL PROPERTIES AND CHEMICAL REACTIVITY PARAMETERS OF ORGANIC COMPOUNDS

    EPA Science Inventory

    The computer program SPARC (Sparc Performs Automated Reasoning in Chemistry)has been under development for several years to estimate physical properties and chemical reactivity parameters of organic compounds strictly from molecular structure. SPARC uses computational algorithms ...

  16. Evaluation of correlation between physical properties and ultrasonic pulse velocity of fired clay samples.

    PubMed

    Özkan, İlker; Yayla, Zeliha

    2016-03-01

    The aim of this study is to establish a correlation between physical properties and ultrasonic pulse velocity of clay samples fired at elevated temperatures. Brick-making clay and pottery clay were studied for this purpose. The physical properties of clay samples were assessed after firing pressed clay samples separately at temperatures of 850, 900, 950, 1000, 1050 and 1100 °C. A commercial ultrasonic testing instrument (Proceq Pundit Lab) was used to evaluate the ultrasonic pulse velocity measurements for each fired clay sample as a function of temperature. It was observed that there became a relationship between physical properties and ultrasonic pulse velocities of the samples. The results showed that in consequence of increasing densification of the samples, the differences between the ultrasonic pulse velocities were higher with increasing temperature. These findings may facilitate the use of ultrasonic pulse velocity for the estimation of physical properties of fired clay samples. PMID:26725032

  17. Sensing at the nanoscale

    NASA Astrophysics Data System (ADS)

    Demming, Anna; Hierold, Christofer

    2013-11-01

    The merits of nanostructures in sensing may seem obvious, yet playing these attributes to their maximum advantage can be a work of genius. As fast as sensing technology is improving, expectations are growing, with demands for cheaper devices with higher sensitivities and an ever increasing range of functionalities and compatibilities. At the same time tough scientific challenges like low power operation, noise and low selectivity are keeping researchers busy. This special issue on sensing at the nanoscale with guest editor Christofer Hierold from ETH Zurich features some of the latest developments in sensing research pushing at the limits of current capabilities. Cheap and easy fabrication is a top priority. Among the most popular nanomaterials in sensing are ZnO nanowires and in this issue Dario Zappa and colleagues at Brescia University in Italy simplify an already cheap and efficient synthesis method, demonstrating ZnO nanowire fabrication directly onto silicon substrates [1]. Meanwhile Nicolae Barson and colleagues in Germany point out the advantages of flame spray pyrolysis fabrication in a topical review [2] and, maximizing on existing resources, researchers in Denmark and Taiwan report cantilever sensing using a US20 commercial DVD-ROM optical pickup unit as the readout source [3]. The sensor is designed to detect physiological concentrations of soluble urokinase plasminogen activator receptor, a protein associated with inflammation due to HIV, cancer and other infectious diseases. With their extreme properties carbon nanostructures feature prominently in the issue, including the demonstration of a versatile and flexible carbon nanotube strain sensor [4] and a graphene charge sensor with sensitivities of the order of 1.3 × 10-3 e Hz-1/2 [5]. The issue of patterning for sensing devices is also tackled by researchers in the US who demonstrate a novel approach for multicomponent pattering metal/metal oxide nanoparticles on graphene [6]. Changes in electrical

  18. Effect of film properties for non-linear DPL model in a nanoscale MOSFET with high-k material: ZrO2/HfO2/La2O3

    NASA Astrophysics Data System (ADS)

    Shomali, Zahra; Ghazanfarian, Jafar; Abbassi, Abbas

    2015-07-01

    Numerical simulation of non-linear non-Fourier heat conduction within a nano-scale metal-oxide-semiconductor field-effect transistor (MOSFET) is presented under the framework of Dual-Phase-Lag model including the boundary phonon scattering. The MOSFET is modeled in four cases of: (I) thin silicon slab, (II) including uniform heat generation, (III) double-layered buried oxide MOSFET with uniform heat generation in silicon-dioxide layer, and (IV) high-k/metal gate transistor. First, four cases are studied under four conditions of (a) constant bulk and (b) constant film thermal properties, (c) temperature-dependent properties of bulk silicon, and (d) temperature-dependent thermal properties of film silicon. The heat source and boundary conditions are similar to what existed in a real MOSFET. It is concluded that in all cases, considering the film properties lowers the temperature jump due to the reduction of the Knudsen number. Furthermore, the speed of heat flux penetration for film properties is less than that of the cases concerning bulk properties. Also, considering the temperature-dependent properties drastically changes the temperature and heat flux distributions within the transistor, which increases the diffusion speed and more, decreases the steady state time. Calculations for case (III) presents that all previous studies have underestimated the value of the peak temperature rise by considering the constant bulk properties of silicon. Also, it is found that among the high-k dielectrics investigated in case (IV), zirconium dioxide shows the least peak temperature rise. This presents that zirconium dioxide is a good candidate as far as the thermal issues are concerned.

  19. Toxicity and physical properties of atrazine and its degradation products: A literature survey

    SciTech Connect

    Pugh, K.C.

    1994-10-01

    The Tennessee Valley Authority`s Environmental Research Center has been developing a means of detoxifying atrazine waste waters using TiO{sub 2} photocatalysis. The toxicity and physical properties of atrazine and its degradation products will probably be required information in obtaining permits from the United States Environmental Protection Agency for the demonstration of any photocatalytic treatment of atrazine waste waters. The following report is a literature survey of the toxicological and physical properties of atrazine and its degradation products.

  20. Physical-chemical properties of chlorinated dibenzo-p-dioxins

    SciTech Connect

    Shiu, W.Y.; Doucette, W.; Gobas, F.A.P.C.; Andren, A.; Mackay, D.

    1988-06-01

    Reported and newly determined experimental data for aqueous solubility, octanol-water partition coefficient, vapor pressure, and Henry's law constants of the poly-chlorinated dibenzo-p-dioxins are presented and reviewed. Correlation equations are derived for these properties as a function of chlorine number and molar volume, which enable the solubility and octanol-water partition coefficients of most congeners to be estimated with an accuracy within a factor of 2 and vapor pressure and Henry's law constant within a factor of 5. It is suggested that properties of homologous series are best correlated by a two-stage process. In the first stage, treated here, simple correlations are developed to establish approximate values as a function of molar volume and chlorine number. This should be followed by a more rigorous second stage treating isomer differences and using more refined molecular descriptors. The data presented here should be sufficiently accurate for many environmental assessment purposes.

  1. Determination of physical properties of fibrous thermal insulation

    NASA Astrophysics Data System (ADS)

    Tilioua, A.; Libessart, L.; Joulin, A.; Lassue, S.; Monod, B.; Jeandel, G.

    2012-10-01

    The objective of this study is to characterize both experimentally and theoretically, conductive and radiative heat transfer within polyester batting. This material is derived from recycled bottles (PET) with fibres of constant diameters. Two other mineral and plant fibrous insulation materials, (glass wool and hemp wool) are also characterized for comparative purposes. To determine the overall thermophysical properties of the tested materials, heat flux measurement are carried out using a device developed in house. The radiative properties of the material are determined by an inverse method based on measurements of transmittance and reflectance using a FTIR spectrometer and by solving the equation of radiative heat transfer. These measures are compared to results of numerical simulations.

  2. Structural and physical properties of BiVO{sub 3}

    SciTech Connect

    Singh, M. P. Razavi, F. S.

    2014-03-31

    We report the phase stabilization and properties of BiVO{sub 3} (BVO) thin films, grown on (001) SrTiO{sub 3} and LaAlO{sub 3}, using the pulsed laser deposition technique. Bi and V are in 3+ oxidation states as measured by using x-ray photoelectrons spectroscopy. BVO exhibits a Curie-Weiss paramagnetic behaviour and about −26 K Weiss temperature. This demonstrates the presence of a strong correlation effect due to the spin fluctuation. Additionally, these films exhibit a semiconducting behaviour owing to the thermally activated conduction process. A plausible explanation of the observed properties is presented by comparing with the closely related LaVO{sub 3} and other orthovanadates.

  3. Active doublet method for measuring small changes in physical properties

    DOEpatents

    Roberts, Peter M.; Fehler, Michael C.; Johnson, Paul A.; Phillips, W. Scott

    1994-01-01

    Small changes in material properties of a work piece are detected by measuring small changes in elastic wave velocity and attenuation within a work piece. Active, repeatable source generate coda wave responses from a work piece, where the coda wave responses are temporally displaced. By analyzing progressive relative phase and amplitude changes between the coda wave responses as a function of elapsed time, accurate determinations of velocity and attenuation changes are made. Thus, a small change in velocity occurring within a sample region during the time periods between excitation origin times (herein called "doublets") will produce a relative delay that changes with elapsed time over some portion of the scattered waves. This trend of changing delay is easier to detect than an isolated delay based on a single arrival and provides a direct measure of elastic wave velocity changes arising from changed material properties of the work piece.

  4. Physical properties of kraft black liquor. Final report. Phase I

    SciTech Connect

    Fricke, A.L.

    1983-12-01

    Methods were selected, equipment installed, and procedures developed for determining rheological properties; for determining thermal properties (stability, density, thermal expansion, and heat capacity); for purification and characterization of lignin (glass transition, stability, weight average molecular weight, and number average molecular weight); and for performing chemical analyses (negative inorganic ions, positive inorganic ions, acid organic salts, lignin, and total solids). A strategy for pulping to supply test liquors was developed, and a statistically designed pulping experiment was specified for a Southern softwood species. Arrangements were made for performing initial pulping work in an industrial pilot plant, and a preliminary set of pulping experiments were conducted. Liquors from the preliminary pulping experiments were used to test procedures and to determine reproducibility of the experiment. Literature was also surveyed and preliminary selection of designs for a pilot digester, and for equipment to determine surface tension were made.

  5. Regional dust deposits on Mars - Physical properties, age, and history

    NASA Technical Reports Server (NTRS)

    Christensen, P. R.

    1986-01-01

    This paper presents a description of the use of Viking infrared thermal mapper (IRTM), earth-based radar, and visual observations for the study of the existence of regional dust deposits. It is pointed out that these observations provide estimates of particle size, rock abundance, surface texture, thermal emissivity, and albedo. These estimates can be used to characterize surface deposits and to determine the degree of surface mantling. Attention is given to the regolith properties, atmospheric dust properties, and a model for formation of low-inertia regions. It is found that global dust storms deposit currently approximately 25 microns of material per year in the equatorial region. Over geologic time this value may vary from 0 to 250 microns due to variations in atmospheric conditions produced by orbital variations.

  6. Physical properties of preserved core from the Geysers scientific corehole

    SciTech Connect

    Roberts, J.J.; Bonner, B.P.; Duba, A.G.; Schneberk, D.L.

    1996-01-24

    X-ray attenuation, electrical conductivity, and ultrasonic velocity are reported for a segment of preserved core from SB-15D, 918 ft. X-ray tomography and ultrasonic measurements change as the core dries, providing information regarding handling and disturbance of the core. Electrical conductivity measurements at reservoir conditions indicate that pore fluid properties and pore microstructure control bulk conductivity. These data are useful for calibration and interpretation of field geophysical measurements.

  7. Physical modifications of polysaccharide from Inonotus obliquus and the antioxidant properties.

    PubMed

    Zhang, Ning; Chen, Haixia; Ma, Lishuai; Zhang, Yu

    2013-03-01

    Physical modification of polysaccharides exerted better biological properties because of the change of physicochemical properties. Polysaccharides from Inonotus obliquus (IOPS) were modified by acid, alkali hydrolysis, thermal and ultrasonic treatment in this study. The physicochemical and antioxidant properties of IOPS and its physical modified products were comparatively investigated by chemical methods, gas chromatography, size exclusion chromatography, scanning electron micrograph, circular dichroism spectra, and ferric reducing power assay and lipid peroxidation inhibition assay, respectively. Results showed that physicochemical and antioxidant properties of IOPS were changed after the physical modification of acid, alkali hydrolysis, thermal and ultrasonic treatment. Thermal treated polysaccharide (Th-IOPS) and ultrasonic treated polysaccharide (Ul-IOPS) showed the properties of lower molecular weight distribution, lower intrinsic viscosity, a hyperbranched conformation, and higher antioxidant abilities on ferric-reducing power and lipid peroxidation inhibition activity compared with the native polysaccharide IOPS. Th-IOPS and Ul-IOPS might be explored as a novel potential antioxidant for food industry. PMID:23270834

  8. Physical properties of the Creutzfeldt-Jakob disease agent

    SciTech Connect

    Sklaviadis, T.K.; Manuelidis, L.; Manuelidis, E.E.

    1989-03-01

    In this report, the authors present the first physical characterization of the Creutzfeld-Jakob disease agent. Preparations with high yields of infectivity (assayed infectious units) were obtained by a novel, gentle procedure in which initially sedimenting Gp34 (prion protein) was disaggregated by a variety of criteria with no subsequent loss of infectivity. Studies with this preparation indicate that most of the Creutzfeldt-Jakob disease agent has both a viruslike size and density. In velocity sedimentation and isopycnic sucrose gradients, infectivity comigrated with nucleic acid-protein complexes of appreciable size.

  9. Magnetic nanoparticles: preparation, physical properties, and applications in biomedicine

    PubMed Central

    2012-01-01

    Finally, we have addressed some relevant findings on the importance of having well-defined synthetic strategies developed for the generation of MNPs, with a focus on particle formation mechanism and recent modifications made on the preparation of monodisperse samples of relatively large quantities not only with similar physical features, but also with similar crystallochemical characteristics. Then, different methodologies for the functionalization of the prepared MNPs together with the characterization techniques are explained. Theorical views on the magnetism of nanoparticles are considered. PMID:22348683

  10. Modelling the historical changes in physical soil properties caused by wind erosion process

    NASA Astrophysics Data System (ADS)

    Lackóová, Lenka

    2016-04-01

    Soil physical properties could be significantly affected by land degradation processes. Spatial variation modelling of physical soil properties in time is important in areas where wind erosion occurs regularly. The objectives of this study were to determine the changes of spatial variability of sand, silt and clay % contents in selected area in Slovakia over 45 years using topsoil physical properties at European scale (using LUCAS topsoil) and historical Complex Soil Survey Data. The Complex Soil Survey was made in the period 1960-1970 for the whole of the Slovak Republic, using a unified methodology to build an important soil properties database including physical topsoil properties. Spatial model distribution using regression kriging algorithm created by Soil Science and Conservation Research Institute was used for comparison with LUCAS topsoil particle size distribution datasets and their derived products of clay, sand and silt % content. The results of this study will show the effects of wind erosion in long time scale. Continual total mass removal during wind erosion can produce dramatic changes in the texture of the soil surface. Fine particles are removed, which tend to concentrate sand as erosion continues. Wind erosion physically removes the most fertile portion of the soil which may lead to lower productivity or destroying the characteristics of topsoil beneficial to plant growth. Historical changes of physical soil properties are discussed in this study.

  11. Stable storage of helium in nanoscale platelets at semicoherent interfaces.

    PubMed

    Kashinath, A; Misra, A; Demkowicz, M J

    2013-02-22

    He implanted into metals precipitates into nanoscale bubbles that may later grow into voids, degrading the properties of engineering alloys. Using multiscale modeling, we show that a different class of He precipitates may form at semicoherent interfaces: nanoscale platelets. These platelets grow by wetting high-energy interface regions, remain stable under irradiation, and reduce He-induced swelling. Stable storage of He at interfaces may impart unprecedented He resistance to future structural materials. PMID:23473167

  12. 22 CFR 72.14 - Nominal possession; property not normally taken into physical possession.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... and quantity that they can readily be taken into physical possession with the rest of the personal... into physical possession. 72.14 Section 72.14 Foreign Relations DEPARTMENT OF STATE PROTECTION AND... States Citizens and Nationals § 72.14 Nominal possession; property not normally taken into...

  13. 22 CFR 72.14 - Nominal possession; property not normally taken into physical possession.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... and quantity that they can readily be taken into physical possession with the rest of the personal... into physical possession. 72.14 Section 72.14 Foreign Relations DEPARTMENT OF STATE PROTECTION AND... States Citizens and Nationals § 72.14 Nominal possession; property not normally taken into...

  14. The interaction of physical properties of seawater via statistical approach

    NASA Astrophysics Data System (ADS)

    Hamzah, Firdaus Mohamad; Jaafar, Othman; Sabri, Samsul Rijal Mohd; Ismail, Mohd Tahir; Jaafar, Khamisah; Arbin, Norazman

    2015-09-01

    It is of importance to determine the relationships between physical parameters in marine ecology. Model and expert opinion are needed for exploration of the form of relationship between two parameters due to the complexity of the ecosystems. These need justification with observed data over a particular periods. Novel statistical techniques such as nonparametric regression is presented to investigate the ecological relationships. These are achieved by demonstrating the features of pH, salinity and conductivity at in Straits of Johor. The monthly data measurements from 2004 until 2013 at a chosen sampling location are examined. Testing for no-effect followed by linearity testing for the relationships between salinity and pH; conductivity and pH, and conductivity and salinity are carried out, with the ecological objectives of investigating the evidence of changes in each of the above physical parameters. The findings reveal the appropriateness of smooth function to explain the variation of pH in response to the changes in salinity whilst the changes in conductivity with regards to different concentrations of salinity could be modelled parametrically. The analysis highlights the importance of both parametric and nonparametric models for assessing ecological response to environmental change in seawater.

  15. Nanoscale thermal transport. II. 2003–2012

    SciTech Connect

    Cahill, David G. Braun, Paul V.; Chen, Gang; Clarke, David R.; Fan, Shanhui; Goodson, Kenneth E.; Keblinski, Pawel; King, William P.; Mahan, Gerald D.; Majumdar, Arun; Maris, Humphrey J.; Phillpot, Simon R.; Pop, Eric; Shi, Li

    2014-03-15

    A diverse spectrum of technology drivers such as improved thermal barriers, higher efficiency thermoelectric energy conversion, phase-change memory, heat-assisted magnetic recording, thermal management of nanoscale electronics, and nanoparticles for thermal medical therapies are motivating studies of the applied physics of thermal transport at the nanoscale. This review emphasizes developments in experiment, theory, and computation in the past ten years and summarizes the present status of the field. Interfaces become increasingly important on small length scales. Research during the past decade has extended studies of interfaces between simple metals and inorganic crystals to interfaces with molecular materials and liquids with systematic control of interface chemistry and physics. At separations on the order of ∼1 nm, the science of radiative transport through nanoscale gaps overlaps with thermal conduction by the coupling of electronic and vibrational excitations across weakly bonded or rough interfaces between materials. Major advances in the physics of phonons include first principles calculation of the phonon lifetimes of simple crystals and application of the predicted scattering rates in parameter-free calculations of the thermal conductivity. Progress in the control of thermal transport at the nanoscale is critical to continued advances in the density of information that can be stored in phase change memory devices and new generations of magnetic storage that will use highly localized heat sources to reduce the coercivity of magnetic media. Ultralow thermal conductivity—thermal conductivity below the conventionally predicted minimum thermal conductivity—has been observed in nanolaminates and disordered crystals with strong anisotropy. Advances in metrology by time-domain thermoreflectance have made measurements of the thermal conductivity of a thin layer with micron-scale spatial resolution relatively routine. Scanning thermal microscopy and

  16. Nanoscale thermal transport. II. 2003-2012

    NASA Astrophysics Data System (ADS)

    Cahill, David G.; Braun, Paul V.; Chen, Gang; Clarke, David R.; Fan, Shanhui; Goodson, Kenneth E.; Keblinski, Pawel; King, William P.; Mahan, Gerald D.; Majumdar, Arun; Maris, Humphrey J.; Phillpot, Simon R.; Pop, Eric; Shi, Li

    2014-03-01

    A diverse spectrum of technology drivers such as improved thermal barriers, higher efficiency thermoelectric energy conversion, phase-change memory, heat-assisted magnetic recording, thermal management of nanoscale electronics, and nanoparticles for thermal medical therapies are motivating studies of the applied physics of thermal transport at the nanoscale. This review emphasizes developments in experiment, theory, and computation in the past ten years and summarizes the present status of the field. Interfaces become increasingly important on small length scales. Research during the past decade has extended studies of interfaces between simple metals and inorganic crystals to interfaces with molecular materials and liquids with systematic control of interface chemistry and physics. At separations on the order of ˜ 1 nm , the science of radiative transport through nanoscale gaps overlaps with thermal conduction by the coupling of electronic and vibrational excitations across weakly bonded or rough interfaces between materials. Major advances in the physics of phonons include first principles calculation of the phonon lifetimes of simple crystals and application of the predicted scattering rates in parameter-free calculations of the thermal conductivity. Progress in the control of thermal transport at the nanoscale is critical to continued advances in the density of information that can be stored in phase change memory devices and new generations of magnetic storage that will use highly localized heat sources to reduce the coercivity of magnetic media. Ultralow thermal conductivity—thermal conductivity below the conventionally predicted minimum thermal conductivity—has been observed in nanolaminates and disordered crystals with strong anisotropy. Advances in metrology by time-domain thermoreflectance have made measurements of the thermal conductivity of a thin layer with micron-scale spatial resolution relatively routine. Scanning thermal microscopy and thermal

  17. Physical properties of salt, anhydrite and gypsum : preliminary report

    USGS Publications Warehouse

    Robertson, Eugene C.; Robie, Richard A.; Books, Kenneth G.

    1958-01-01

    This summary is the result of a search of the available literature. Emphasis is placed on the mechanical and calorimetric properties of salt; the measurements of elastic, thermal, magnetic, and mass properties of salt are merely tabulated. Under hydrostatic pressure 100 percent at a nearly constant stress difference of about 300 kg/cm2. Similarily, under temperatures > 400?C at one atmosphere, salt deforms plastically to strains > 100 percent under stress differences of about 100 kg/cm2. Entha1pies were calculated for various temperatures to 2,000? C from the low temperature and high temperature heat capacities and the heats of solution of the following minerals: salt (or halite), NaCl; anhydrite, CaS04; quartz, Si02; and calcite, CaC03. Three combinations of these minerals were assumed to represent three possible natural salt beds, and the heats required to raise the temperature of each to 1,500?C and to 2,000?C were calculated. For a half and half mixture of salt and anhydrite, 1,300 cal/gm were required to raise the temperature to 2,000?C. For an evaporite containing 60 percent salt and about equal amounts of anhydrite, calcite, and quartz, 1,100 cal/gm are required to raise the temperature to 2,OOO?C. Most of the measurements of the elastic moduli were made on single crystals of salt, anhydrite, and gypsum. For the most part, the measurements of density, magnetic susceptibility, and other properties were made on natural salt samples.

  18. CALL FOR PAPERS: Special Issue on Light Control at the Nanoscale

    NASA Astrophysics Data System (ADS)

    Kral, P.; Shapiro, M.

    2006-11-01

    Journal of Physics B: Atomic, Molecular and Optical Physics invites you to submit a paper to a forthcoming special issue on Light Control at the Nanoscale to appear in 2007. Please see pdf for details.

  19. Complex Study of the Physical Properties of Reticulated Vitreous Carbon

    NASA Astrophysics Data System (ADS)

    Alifanov, O. M.; Cherepanov, V. V.; Morzhukhina, A. V.

    2015-01-01

    We give an example of using a two-level identifi cation system incorporating an augmented mathematical model covering the structure, the thermal, electrophysical, and optical properties of nonmetallic ultraporous reticulated materials. The model, when combined with a nonstationary thermal experiment and methods of the theory of inverse heat transfer problems, permits determining the little studied characteristics of the above materials. We present some of the results of investigations of reticulated vitreous carbon confirming the possibility of using it in a number of engineering applications.

  20. Some physical properties of Apollo 12 lunar samples

    NASA Technical Reports Server (NTRS)

    Gold, T.; Oleary, B. T.; Campbell, M.

    1971-01-01

    The size distribution of the lunar fines is measured, and small but significant differences are found between the Apollo 11 and 12 samples as well as among the Apollo 12 core samples. The observed differences in grain size distribtuion in the core samples are related to surface transportation processes, and the importance of a sedimentation process versus meteoritic impact gardening of the mare grounds is discussed. The optical and the radio frequency electrical properties are measured and are also found to differ only slightly from Apollo 11 results.