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Sample records for mass properties engineering

  1. E-Standards For Mass Properties Engineering

    NASA Technical Reports Server (NTRS)

    Cerro, Jeffrey A.

    2008-01-01

    A proposal is put forth to promote the concept of a Society of Allied Weight Engineers developed voluntary consensus standard for mass properties engineering. This standard would be an e-standard, and would encompass data, data manipulation, and reporting functionality. The standard would be implemented via an open-source SAWE distribution site with full SAWE member body access. Engineering societies and global standards initiatives are progressing toward modern engineering standards, which become functioning deliverable data sets. These data sets, if properly standardized, will integrate easily between supplier and customer enabling technically precise mass properties data exchange. The concepts of object-oriented programming support all of these requirements, and the use of a JavaTx based open-source development initiative is proposed. Results are reported for activity sponsored by the NASA Langley Research Center Innovation Institute to scope out requirements for developing a mass properties engineering e-standard. An initial software distribution is proposed. Upon completion, an open-source application programming interface will be available to SAWE members for the development of more specific programming requirements that are tailored to company and project requirements. A fully functioning application programming interface will permit code extension via company proprietary techniques, as well as through continued open-source initiatives.

  2. New Mass Properties Engineers Aerospace Ballasting Challenge Facilitated by the SAWE Community

    NASA Technical Reports Server (NTRS)

    Cutright, Amanda; Shaughnessy, Brendan

    2010-01-01

    The discipline of Mass Properties Engineering tends to find the engineers; not typically vice versa. In this case, two engineers quickly found their new responsibilities deep in many aspects of mass properties engineering and required to meet technical challenges in a fast paced environment. As part of NASA's Constellation Program, a series of flight tests will be conducted to evaluate components of the new spacecraft launch vehicles. One of these tests is the Pad Abort 1 (PA-1) flight test which will test the Launch Abort System (LAS), a system designed to provide escape for astronauts in the event of an emergency. The Flight Test Articles (FTA) used in this flight test are required to match mass properties corresponding to the operational vehicle, which has a continually evolving design. Additionally, since the structure and subsystems for the Orion Crew Module (CM) FTA are simplified versions of the final product, thousands of pounds of ballast are necessary to achieve the desired mass properties. These new mass properties engineers are responsible for many mass properties aspects in support of the flight test, including meeting the ballasting challenge for the CM Boilerplate FTA. SAWE expert and experienced mass properties engineers, both those that are directly on the team and many that supported via a variety of Society venues, significantly contributed to facilitating the success of addressing this particular mass properties ballasting challenge, in addition to many other challenges along the way. This paper discusses the details regarding the technical aspects of this particular mass properties challenge, as well as identifies recommendations for new mass properties engineers that were learned from the SAWE community along the way.

  3. Models for predicting the mass of lime fruits by some engineering properties.

    PubMed

    Miraei Ashtiani, Seyed-Hassan; Baradaran Motie, Jalal; Emadi, Bagher; Aghkhani, Mohammad-Hosein

    2014-11-01

    Grading fruits based on mass is important in packaging and reduces the waste, also increases the marketing value of agricultural produce. The aim of this study was mass modeling of two major cultivars of Iranian limes based on engineering attributes. Models were classified into three: 1-Single and multiple variable regressions of lime mass and dimensional characteristics. 2-Single and multiple variable regressions of lime mass and projected areas. 3-Single regression of lime mass based on its actual volume and calculated volume assumed as ellipsoid and prolate spheroid shapes. All properties considered in the current study were found to be statistically significant (ρ < 0.01). The results indicated that mass modeling of lime based on minor diameter and first projected area are the most appropriate models in the first and the second classifications, respectively. In third classification, the best model was obtained on the basis of the prolate spheroid volume. It was finally concluded that the suitable grading system of lime mass is based on prolate spheroid volume.

  4. Mass drivers. 3: Engineering

    NASA Technical Reports Server (NTRS)

    Arnold, W.; Bowen, S.; Cohen, S.; Fine, K.; Kaplan, D.; Kolm, M.; Kolm, H.; Newman, J.; Oneill, G. K.; Snow, W.

    1979-01-01

    The last of a series of three papers by the Mass-Driver Group of the 1977 Ames Summer Study is presented. It develops the engineering principles required to implement the basic mass-driver. Optimum component mass trade-offs are derived from a set of four input parameters, and the program used to design a lunar launcher. The mass optimization procedures is then incorporated into a more comprehensive mission optimization program called OPT-4, which evaluates an optimized mass-driver reaction engine and its performance in a range of specified missions. Finally, this paper discusses, to the extent that time permitted, certain peripheral problems: heating effects in buckets due to magnetic field ripple; an approximate derivation of guide force profiles; the mechanics of inserting and releasing payloads; the reaction mass orbits; and a proposed research and development plan for implementing mass drivers.

  5. Engineering correlations of variable-property effects on laminar forced convection mass transfer for dilute vapor species and small particles in air

    NASA Technical Reports Server (NTRS)

    Gokoglu, S. A.; Rosner, D. E.

    1984-01-01

    A simple engineering correlation scheme is developed to predict the variable property effects on dilute species laminar forced convection mass transfer applicable to all vapor molecules or Brownian diffusing small particle, covering the surface to mainstream temperature ratio of 0.25 T sub W/T sub e 4. The accuracy of the correlation is checked against rigorous numerical forced convection laminar boundary layer calculations of flat plate and stagnation point flows of air containing trace species of Na, NaCl, NaOH, Na2SO4, K, KCl, KOH, or K2SO4 vapor species or their clusters. For the cases reported here the correlation had an average absolute error of only 1 percent (maximum 13 percent) as compared to an average absolute error of 18 percent (maximum 54 percent) one would have made by using the constant-property results.

  6. a Tool Development of Mass Properties Database of a Satellite

    NASA Astrophysics Data System (ADS)

    Moon, Hong-Youl; Kim, Gyu-Sun

    2003-12-01

    One of the mechanical system engineer's tasks of a satellite design and development is to make the control plan, keep track and estimate the characteristics of system mass properties. As the design phases are go, mass properties related activities also transit as like a data collection, system mass property estimation and measurement. Fidelity of mass properties database should be confirmed through measurement test. In this paper the control plan and estimation of system mass properties are explained by the actual data and experience of the development of satellite and the fidelity of mass properties database was confirmed through measurement test.

  7. Mass properties measurement system dynamics

    NASA Technical Reports Server (NTRS)

    Doty, Keith L.

    1993-01-01

    The MPMS mechanism possess two revolute degrees-of-freedom and allows the user to measure the mass, center of gravity, and the inertia tensor of an unknown mass. The dynamics of the Mass Properties Measurement System (MPMS) from the Lagrangian approach to illustrate the dependency of the motion on the unknown parameters.

  8. ACTOMP - AUTOCAD TO MASS PROPERTIES

    NASA Technical Reports Server (NTRS)

    Jones, A.

    1994-01-01

    AutoCAD to Mass Properties was developed to facilitate quick mass properties calculations of structures having many simple elements in a complex configuration such as trusses or metal sheet containers. Calculating the mass properties of structures of this type can be a tedious and repetitive process, but ACTOMP helps automate the calculations. The structure can be modelled in AutoCAD or a compatible CAD system in a matter of minutes using the 3-Dimensional elements. This model provides all the geometric data necessary to make a mass properties calculation of the structure. ACTOMP reads the geometric data of a drawing from the Drawing Interchange File (DXF) used in AutoCAD. The geometric entities recognized by ACTOMP include POINTs, 3DLINEs, and 3DFACEs. ACTOMP requests mass, linear density, or area density of the elements for each layer, sums all the elements and calculates the total mass, center of mass (CM) and the mass moments of inertia (MOI). AutoCAD utilizes layers to define separate drawing planes. ACTOMP uses layers to differentiate between multiple types of similar elements. For example if a structure is made of various types of beams, modeled as 3DLINEs, each with a different linear density, the beams can be grouped by linear density and each group placed on a separate layer. The program will request the linear density of 3DLINEs for each new layer it finds as it processes the drawing information. The same is true with POINTs and 3DFACEs. By using layers this way a very complex model can be created. POINTs are used for point masses such as bolts, small machine parts, or small electronic boxes. 3DLINEs are used for beams, bars, rods, cables, and other similarly slender elements. 3DFACEs are used for planar elements. 3DFACEs may be created as 3 or 4 Point faces. Some examples of elements that might be modelled using 3DFACEs are plates, sheet metal, fabric, boxes, large diameter hollow cylinders and evenly distributed masses. ACTOMP was written in Microsoft

  9. Error analysis of system mass properties

    NASA Technical Reports Server (NTRS)

    Brayshaw, J.

    1984-01-01

    An attempt is made to verify the margin of system mass properties over values that are sufficient for the support of such other critical system requirements as those of dynamic control. System nominal mass properties are designed on the basis of an imperfect understanding of the mass and location of constituent elements; the effect of such element errors is to introduce net errors into calculated system mass properties. The direct measurement of system mass properties is, however, impractical. Attention is given to these issues in the case of the Galileo spacecraft.

  10. Computing Mass Properties From AutoCAD

    NASA Technical Reports Server (NTRS)

    Jones, A.

    1990-01-01

    Mass properties of structures computed from data in drawings. AutoCAD to Mass Properties (ACTOMP) computer program developed to facilitate quick calculations of mass properties of structures containing many simple elements in such complex configurations as trusses or sheet-metal containers. Mathematically modeled in AutoCAD or compatible computer-aided design (CAD) system in minutes by use of three-dimensional elements. Written in Microsoft Quick-Basic (Version 2.0).

  11. Engineering optical properties of semiconductor metafilm superabsorbers

    NASA Astrophysics Data System (ADS)

    Kim, Soo Jin; Fan, Pengyu; Kang, Ju-Hyung; Brongersma, Mark L.

    2016-04-01

    Light absorption in ultrathin layer of semiconductor has been considerable interests for many years due to its potential applications in various optical devices. In particular, there have been great efforts to engineer the optical properties of the film for the control of absorption spectrums. Whereas the isotropic thin films have intrinsic optical properties that are fixed by materials' properties, metafilm that are composed by deep subwavelength nano-building blocks provides significant flexibilities in controlling the optical properties of the designed effective layers. Here, we present the ultrathin semiconductor metafilm absorbers by arranging germanium (Ge) nanobeams in deep subwavelength scale. Resonant properties of high index semiconductor nanobeams play a key role in designing effective optical properties of the film. We demonstrate this in theory and experimental measurements to build a designing rule of efficient, controllable metafilm absorbers. The proposed strategy of engineering optical properties could open up wide range of applications from ultrathin photodetection and solar energy harvesting to the diverse flexible optoelectronics.

  12. Semiconductor alloys - Structural property engineering

    NASA Technical Reports Server (NTRS)

    Sher, A.; Van Schilfgaarde, M.; Berding, M.; Chen, A.-B.

    1987-01-01

    Semiconductor alloys have been used for years to tune band gaps and average bond lengths to specific applications. Other selection criteria for alloy composition, and a growth technique designed to modify their structural properties, are presently considered. The alloys Zn(1-y)Cd(y)Te and CdSe(y)Te(1-y) are treated as examples.

  13. MASPROP- MASS PROPERTIES OF A RIGID STRUCTURE

    NASA Technical Reports Server (NTRS)

    Hull, R. A.

    1994-01-01

    The computer program MASPROP was developed to rapidly calculate the mass properties of complex rigid structural systems. This program's basic premise is that complex systems can be adequately described by a combination of basic elementary structural shapes. Thirteen widely used basic structural shapes are available in this program. They are as follows: Discrete Mass, Cylinder, Truncated Cone, Torus, Beam (arbitrary cross section), Circular Rod (arbitrary cross section), Spherical Segment, Sphere, Hemisphere, Parallelepiped, Swept Trapezoidal Panel, Symmetric Trapezoidal Panels, and a Curved Rectangular Panel. MASPROP provides a designer with a simple technique that requires minimal input to calculate the mass properties of a complex rigid structure and should be useful in any situation where one needs to calculate the center of gravity and moments of inertia of a complex structure. Rigid body analysis is used to calculate mass properties. Mass properties are calculated about component axes that have been rotated to be parallel to the system coordinate axes. Then the system center of gravity is calculated and the mass properties are transferred to axes through the system center of gravity by using the parallel axis theorem. System weight, moments of inertia about the system origin, and the products of inertia about the system center of mass are calculated and printed. From the information about the system center of mass the principal axes of the system and the moments of inertia about them are calculated and printed. The only input required is simple geometric data describing the size and location of each element and the respective material density or weight of each element. This program is written in FORTRAN for execution on a CDC 6000 series computer with a central memory requirement of approximately 62K (octal) of 60 bit words. The development of this program was completed in 1978.

  14. Study of solid rocket motors for a space shuttle booster. Volume 4: Mass properties report

    NASA Technical Reports Server (NTRS)

    Vonderesch, A. H.

    1972-01-01

    Mass properties data for the 156 inch diameter, parallel burn, solid propellant rocket engine for the space shuttle booster are presented. Design ground rules and assumptions applicable to generation of the mass properties data are described, together with pertinent data sources.

  15. Evaluating word semantic properties using Sketch Engine

    NASA Astrophysics Data System (ADS)

    Stoykova, Velislava; Simkova, Maria

    2015-02-01

    The paper describes approach to use statistically-based tools incorporated into Sketch Engine system for electronic text corpora processing to mining big textual data for search and extract word semantic properties. It presents and compares series of word search experiments using different statistical approaches and evaluates results for Bulgarian language EUROPARL 7 Corpus search to extract word semantic properties. Finally, the methodology is extended for multilingual application using Slovak language EUROPARL 7 Corpus.

  16. Lithophysal Rock Mass Mechanical Properties of the Repository Host Horizon

    SciTech Connect

    D. Rigby

    2004-11-10

    The purpose of this calculation is to develop estimates of key mechanical properties for the lithophysal rock masses of the Topopah Spring Tuff (Tpt) within the repository host horizon, including their uncertainties and spatial variability. The mechanical properties to be characterized include an elastic parameter, Young's modulus, and a strength parameter, uniaxial compressive strength. Since lithophysal porosity is used as a surrogate property to develop the distributions of the mechanical properties, an estimate of the distribution of lithophysal porosity is also developed. The resulting characterizations of rock parameters are important for supporting the subsurface design, developing the preclosure safety analysis, and assessing the postclosure performance of the repository (e.g., drift degradation and modeling of rockfall impacts on engineered barrier system components).

  17. Engineered Proteins: Redox Properties and Their Applications

    PubMed Central

    Prabhulkar, Shradha; Tian, Hui; Wang, Xiaotang; Zhu, Jun-Jie

    2012-01-01

    Abstract Oxidoreductases and metalloproteins, representing more than one third of all known proteins, serve as significant catalysts for numerous biological processes that involve electron transfers such as photosynthesis, respiration, metabolism, and molecular signaling. The functional properties of the oxidoreductases/metalloproteins are determined by the nature of their redox centers. Protein engineering is a powerful approach that is used to incorporate biological and abiological redox cofactors as well as novel enzymes and redox proteins with predictable structures and desirable functions for important biological and chemical applications. The methods of protein engineering, mainly rational design, directed evolution, protein surface modifications, and domain shuffling, have allowed the creation and study of a number of redox proteins. This review presents a selection of engineered redox proteins achieved through these methods, resulting in a manipulation in redox potentials, an increase in electron-transfer efficiency, and an expansion of native proteins by de novo design. Such engineered/modified redox proteins with desired properties have led to a broad spectrum of practical applications, ranging from biosensors, biofuel cells, to pharmaceuticals and hybrid catalysis. Glucose biosensors are one of the most successful products in enzyme electrochemistry, with reconstituted glucose oxidase achieving effective electrical communication with the sensor electrode; direct electron-transfer-type biofuel cells are developed to avoid thermodynamic loss and mediator leakage; and fusion proteins of P450s and redox partners make the biocatalytic generation of drug metabolites possible. In summary, this review includes the properties and applications of the engineered redox proteins as well as their significance and great potential in the exploration of bioelectrochemical sensing devices. Antioxid. Redox Signal. 17, 1796–1822. PMID:22435347

  18. Engineering properties of inorganic polymer concretes (IPCs)

    SciTech Connect

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

    2007-02-15

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

  19. Model-Based Systems Engineering Approach to Managing Mass Margin

    NASA Technical Reports Server (NTRS)

    Chung, Seung H.; Bayer, Todd J.; Cole, Bjorn; Cooke, Brian; Dekens, Frank; Delp, Christopher; Lam, Doris

    2012-01-01

    When designing a flight system from concept through implementation, one of the fundamental systems engineering tasks ismanaging the mass margin and a mass equipment list (MEL) of the flight system. While generating a MEL and computing a mass margin is conceptually a trivial task, maintaining consistent and correct MELs and mass margins can be challenging due to the current practices of maintaining duplicate information in various forms, such as diagrams and tables, and in various media, such as files and emails. We have overcome this challenge through a model-based systems engineering (MBSE) approach within which we allow only a single-source-of-truth. In this paper we describe the modeling patternsused to capture the single-source-of-truth and the views that have been developed for the Europa Habitability Mission (EHM) project, a mission concept study, at the Jet Propulsion Laboratory (JPL).

  20. An Engineered Anisotropic Nanofilm with Unidirectional Wetting Properties

    DTIC Science & Technology

    2010-01-01

    ARTICLES PUBLISHED ONLINE: 10 OCTOBER 2010 | DOI: 10.1038/NMAT2864 An engineered anisotropic nanofilm with unidirectional wetting properties Niranjan...body3. Engineering synthetic materials with such anisotropic adhesive properties has led to advances in digitalmicrofluidic devices5,6 andmedicine7,8...The anisotropic wetting properties of existing engineered surfaces are derived either from spatial gradients (for example, temperature, surface

  1. Engineering electrical properties of graphene: chemical approaches

    NASA Astrophysics Data System (ADS)

    Kim, Yong-Jin; Kim, Yuna; Novoselov, Konstantin; Hong, Byung Hee

    2015-12-01

    To ensure the high performance of graphene-based devices, it is necessary to engineer the electrical properties of graphene with enhanced conductivity, controlled work function, opened or closed bandgaps, etc. This can be performed by various non-covalent chemical approaches, including molecular adsorption, substrate-induced doping, polymerization on graphene, deposition of metallic thin films or nanoparticles, etc. In addition, covalent approaches such as the substitution of carbon atoms with boron or nitrogen and the functionalization with hydrogen or fluorine are useful to tune the bandgaps more efficiently, with better uniformity and stability. In this review, representative examples of chemically engineered graphene and its device applications will be reviewed, and remaining challenges will be discussed.

  2. AGN Host Galaxy Properties And Mass Function

    NASA Astrophysics Data System (ADS)

    Bongiorno, Angela

    2016-10-01

    Supermassive black hole growth, nuclear activity, and galaxy evolution have been found to be closely related. In the context of AGN-galaxy coevolution, I will discuss about the relation found between the host galaxy properties and the central BH and I will present the latest determination of the host galaxy stellar mass function (HGMF), and the specific accretion rate distribution function (SARDF), derived from the XMM-COSMOS sample up to z˜2.5, with particular focus on AGN feedback as possible responsible mechanism for galaxy quenching.

  3. Design properties of hydrogel tissue-engineering scaffolds

    PubMed Central

    Zhu, Junmin; Marchant, Roger E

    2011-01-01

    This article summarizes the recent progress in the design and synthesis of hydrogels as tissue-engineering scaffolds. Hydrogels are attractive scaffolding materials owing to their highly swollen network structure, ability to encapsulate cells and bioactive molecules, and efficient mass transfer. Various polymers, including natural, synthetic and natural/synthetic hybrid polymers, have been used to make hydrogels via chemical or physical crosslinking. Recently, bioactive synthetic hydrogels have emerged as promising scaffolds because they can provide molecularly tailored biofunctions and adjustable mechanical properties, as well as an extracellular matrix-like microenvironment for cell growth and tissue formation. This article addresses various strategies that have been explored to design synthetic hydrogels with extracellular matrix-mimetic bioactive properties, such as cell adhesion, proteolytic degradation and growth factor-binding. PMID:22026626

  4. Variability in properties of Salado Mass Concrete

    SciTech Connect

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

    1995-08-01

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

  5. NASA Dryden: Flight Loads Lab Capabilities and Mass Properties Testing

    NASA Technical Reports Server (NTRS)

    Wolfe, David Michael; Bakalyar, John A.

    2011-01-01

    This presentation covers the basic capabilities of the Dryden Flight Loads Lab. It also covers in detail the mass properties capabilities of the loads lab, focusing on the recent mass properties testing of the X-48B, and the recent tests of the Dynamic Inertia Measurement method (DIMM). Presentation focuses on the test methods and issues discovered during the mass properties testing of the X-48B leading to the requirement of new instrumentation on all conventional mass properties testing. Presentation also focuses on development of DIMM for replacement of conventional mass properties tests.

  6. Mass Properties for Space Systems Standards Development

    NASA Technical Reports Server (NTRS)

    Beech, Geoffrey

    2013-01-01

    Current Verbiage in S-120 Applies to Dry Mass. Mass Margin is difference between Required Mass and Predicted Mass. Performance Margin is difference between Predicted Performance and Required Performance. Performance estimates and corresponding margin should be based on Predicted Mass (and other inputs). Contractor Mass Margin reserved from Performance Margin. Remaining performance margin allocated according to mass partials. Compliance can be evaluated effectively by comparison of three areas (preferably on a single sheet). Basic and Predicted Mass (including historical trend). Aggregate potential changes (threats and opportunities) which gives Mass Forecast. Mass Maturity by category (Estimated/Calculated/Actual).

  7. Engineering optical properties using plasmonic nanostructures

    NASA Astrophysics Data System (ADS)

    Tamma, Venkata Ananth

    Plasmonic nanostructures can be engineered to take on unusual optical properties not found in natural materials. The optical responses of plasmonic materials are functions of the structural parameters and symmetry of the nanostructures, material parameters of the nanostructure and its surroundings and the incidence angle, frequency and polarization state of light. The scattering and hence the visibility of an object could be reduced by coating it with a plasmonic material. In this thesis, presented is an optical frequency scattering cancelation device composed of a silicon nanorod coated by a plasmonic gold nanostructure. The principle of operation was theoretically analyzed using Mie theory and the device design was verified by extensive numerical simulations. The device was fabricated using a combination of nanofabrication techniques such as electron beam lithography and focused ion beam milling. The optical responses of the scattering cancelation device and a control sample of bare silicon rod were directly visualized using near-field microscopy coupled with heterodyne interferometric detection. The experimental results were analyzed and found to match very well with theoretical prediction from numerical simulations thereby validating the design principles and our implementation. Plasmonic nanostructures could be engineered to exhibit unique optical properties such as Fano resonance characterized by narrow asymmetrical lineshape. We present dynamic tuning and symmetry lowering of Fano resonances in plasmonic nanostructures fabricated on flexible substrates. The tuning of Fano resonance was achieved by application of uniaxial mechanical stress. The design of the nanostructures was facilitated by extensive numerical simulations and the symmetry lowering was analyzed using group theoretical methods. The nanostructures were fabricated using electron beam lithography and optically characterized for various mechanical stress. The experimental results were in good

  8. Genetic Engineering of Optical Properties of Biomaterials

    NASA Astrophysics Data System (ADS)

    Gourley, Paul; Naviaux, Robert; Yaffe, Michael

    2008-03-01

    Baker's yeast cells are easily cultured and can be manipulated genetically to produce large numbers of bioparticles (cells and mitochondria) with controllable size and optical properties. We have recently employed nanolaser spectroscopy to study the refractive index of individual cells and isolated mitochondria from two mutant strains. Results show that biomolecular changes induced by mutation can produce bioparticles with radical changes in refractive index. Wild-type mitochondria exhibit a distribution with a well-defined mean and small variance. In striking contrast, mitochondria from one mutant strain produced a histogram that is highly collapsed with a ten-fold decrease in the mean and standard deviation. In a second mutant strain we observed an opposite effect with the mean nearly unchanged but the variance increased nearly a thousand-fold. Both histograms could be self-consistently modeled with a single, log-normal distribution. The strains were further examined by 2-dimensional gel electrophoresis to measure changes in protein composition. All of these data show that genetic manipulation of cells represents a new approach to engineering optical properties of bioparticles.

  9. Property-Based Software Engineering Measurement

    NASA Technical Reports Server (NTRS)

    Briand, Lionel; Morasca, Sandro; Basili, Victor R.

    1995-01-01

    Little theory exists in the field of software system measurement. Concepts such as complexity, coupling, cohesion or even size are very often subject to interpretation and appear to have inconsistent definitions in the literature. As a consequence, there is little guidance provided to the analyst attempting to define proper measures for specific problems. Many controversies in the literature are simply misunderstandings and stem from the fact that some people talk about different measurement concepts under the same label (complexity is the most common case). There is a need to define unambiguously the most important measurement concepts used in the measurement of software products. One way of doing so is to define precisely what mathematical properties characterize these concepts regardless of the specific software artifacts to which these concepts are applied. Such a mathematical framework could generate a consensus in the software engineering community and provide a means for better communication among researchers, better guidelines for analysis, and better evaluation methods for commercial static analyzers for practitioners. In this paper, we propose a mathematical framework which is generic, because it is not specific to any particular software artifact, and rigorous, because it is based on precise mathematical concepts. This framework defines several important measurement concepts (size, length, complexity, cohesion, coupling). It is not intended to be complete or fully objective; other frameworks could have been proposed and different choices could have been made. However, we believe that the formalism and properties we introduce are convenient and intuitive. In addition, we have reviewed the literature on this subject and compared it with our work. This framework contributes constructively to a firmer theoretical ground of software measurement.

  10. Property-Based Software Engineering Measurement

    NASA Technical Reports Server (NTRS)

    Briand, Lionel C.; Morasca, Sandro; Basili, Victor R.

    1997-01-01

    Little theory exists in the field of software system measurement. Concepts such as complexity, coupling, cohesion or even size are very often subject to interpretation and appear to have inconsistent definitions in the literature. As a consequence, there is little guidance provided to the analyst attempting to define proper measures for specific problems. Many controversies in the literature are simply misunderstandings and stem from the fact that some people talk about different measurement concepts under the same label (complexity is the most common case). There is a need to define unambiguously the most important measurement concepts used in the measurement of software products. One way of doing so is to define precisely what mathematical properties characterize these concepts, regardless of the specific software artifacts to which these concepts are applied. Such a mathematical framework could generate a consensus in the software engineering community and provide a means for better communication among researchers, better guidelines for analysts, and better evaluation methods for commercial static analyzers for practitioners. In this paper, we propose a mathematical framework which is generic, because it is not specific to any particular software artifact and rigorous, because it is based on precise mathematical concepts. We use this framework to propose definitions of several important measurement concepts (size, length, complexity, cohesion, coupling). It does not intend to be complete or fully objective; other frameworks could have been proposed and different choices could have been made. However, we believe that the formalisms and properties we introduce are convenient and intuitive. This framework contributes constructively to a firmer theoretical ground of software measurement.

  11. Mechanical properties of natural cartilage and tissue-engineered constructs.

    PubMed

    Little, Christopher James; Bawolin, Nahshon Kenneth; Chen, Xiongbiao

    2011-08-01

    There has been much research over the past two decades with the aim of engineering cartilage constructs for repairing or restoring damaged cartilage. To engineer healthy neocartilage, the constructs must have mechanical properties matching those of native cartilage as well as appropriate for the loading conditions of the joint. This article discusses the mechanical behavior of native cartilage and surveys different types of tensile, compressive, and shear tests with their limitations. It also comprehensively reviews recent work and achievements in developing the mathematical models representing the mechanical properties of both native and engineered cartilage. Different methods for enhancing the mechanical properties of engineered cartilage are also discussed, including scaffold design, mechanical stimulation, and chemical stimulation. This article concludes with recommendations for future research aimed at achieving engineered cartilage with mechanical properties matching those found in native cartilage.

  12. Textile Processes for Engineering Tissues with Biomimetic Architectures and Properties.

    PubMed

    Fallahi, Afsoon; Khademhosseini, Ali; Tamayol, Ali

    2016-09-01

    Textile technologies in which fibers containing biological factors and cells are formed and assembled into constructs with biomimetic properties have attracted significant attention in the field of tissue engineering. This Forum article highlights the most prominent advances of the field in the areas of fiber fabrication and construct engineering.

  13. Lunar surface engineering properties experiment definition

    NASA Technical Reports Server (NTRS)

    Mitchell, J. K.; Goodman, R. E.; Hurlbut, F. C.; Houston, W. N.; Willis, D. R.; Witherspoon, P. A.; Hovland, H. J.

    1971-01-01

    Research on the mechanics of lunar soils and on developing probes to determine the properties of lunar surface materials is summarized. The areas of investigation include the following: soil simulation, soil property determination using an impact penetrometer, soil stabilization using urethane foam or phenolic resin, effects of rolling boulders down lunar slopes, design of borehole jack and its use in determining failure mechanisms and properties of rocks, and development of a permeability probe for measuring fluid flow through porous lunar surface materials.

  14. Mass properties survey of solar array technologies

    NASA Technical Reports Server (NTRS)

    Kraus, Robert

    1991-01-01

    An overview of the technologies, electrical performance, and mass characteristics of many of the presently available and the more advanced developmental space solar array technologies is presented. Qualitative trends and quantitative mass estimates as total array output power is increased from 1 kW to 5 kW at End of Life (EOL) from a single wing are shown. The array technologies are part of a database supporting an ongoing solar power subsystem model development for top level subsystem and technology analyses. The model is used to estimate the overall electrical and thermal performance of the complete subsystem, and then calculate the mass and volume of the array, batteries, power management, and thermal control elements as an initial sizing. The array types considered here include planar rigid panel designs, flexible and rigid fold-out planar arrays, and two concentrator designs, one with one critical axis and the other with two critical axes. Solar cell technologies of Si, GaAs, and InP were included in the analyses. Comparisons were made at the array level; hinges, booms, harnesses, support structures, power transfer, and launch retention mountings were included. It is important to note that the results presented are approximations, and in some cases revised or modified performance and mass estimates of specific designs.

  15. 'Food for Engineers': Intellectual Property Education for Innovators

    ERIC Educational Resources Information Center

    Soetendorp, Ruth

    2004-01-01

    Intellectual property competence can assist individuals and organizations to capitalize on opportunities presented by accelerating developments in the knowledge economy. Engineers translate ideas into concrete solutions, which are frequently useful and commercially valuable, if the intrinsic intellectual property has been identified and protected.…

  16. Observational Properties of Coronal Mass Ejections

    DTIC Science & Technology

    2006-01-01

    disconnection leads to interplan- etary magnetic fields completely unattached to the corona , for which solar wind signatures are rarely, if ever, seen...the properties over the solar cycle. The corona - active region, Astrophys. J., 575, 1116, 2002. graph observations have been supplemented with ground...Approved for Public Release; Distribution Unlimited. 13. SUPPLEMENTARY NOTES REPRINTED FROM: SOLAR ERUPTIONS AND ENERGETIC PARTICLES, Geophysical Monograph

  17. IMP: Interactive mass properties program. Volume 1: Program description

    NASA Technical Reports Server (NTRS)

    Stewart, W. A.

    1976-01-01

    A method of computing a weights and center of gravity analysis of a flight vehicle using interactive graphical capabilities of the Adage 340 computer is described. The equations used to calculate area, volume, and mass properties are based on elemental surface characteristics. The input/output methods employ the graphic support of the Adage computer. Several interactive program options are available for analyzing the mass properties of a vehicle. These options are explained.

  18. Mass properties measurement system: Dynamics and statics measurements

    NASA Technical Reports Server (NTRS)

    Doty, Keith L.

    1993-01-01

    This report presents and interprets experimental data obtained from the Mass Properties Measurement System (MPMS). Statics measurements yield the center-of-gravity of an unknown mass and dynamics measurements yield its inertia matrix. Observations of the MPMS performance has lead us to specific design criteria and an understanding of MPMS limitations.

  19. Innovative mechanism for measuring the mass properties of an object

    NASA Technical Reports Server (NTRS)

    Wolcott, Kedron R.; Graham, Todd A.; Doty, Keith L.

    1994-01-01

    The Kennedy Space Center Robotics Group recently completed development and testing on a novel approach to measure the mass properties of a rigid body. This unique design can measure the payload's weight, mass center location, and moments of inertia about three orthogonal axes. Furthermore, these measurements only require a single torque sensor and a single angular position sensor.

  20. Systematic characterization of porosity and mass transport and mechanical properties of porous polyurethane scaffolds.

    PubMed

    Wang, Yu-Fu; Barrera, Carlos M; Dauer, Edward A; Gu, Weiyong; Andreopoulos, Fotios; Huang, C-Y Charles

    2017-01-01

    One of the key challenges in porous scaffold design is to create a porous structure with desired mechanical function and mass transport properties which support delivery of biofactors and development of function tissue substitute. In recent years, polyurethane (PU) has become one of the most popular biomaterials in various tissue engineering fields. However, there are no studies fully investigating the relations between porosity and both mass transport and mechanical properties of PU porous scaffolds. In this paper, we fabricated PU scaffolds by combining phase inversion and salt (sodium chloride) leaching methods. The tensile and compressive moduli were examined on PU scaffolds fabricated with different PU concentrations (25%, 20% and 15% w/v) and salt/PU weight ratios (9/1, 6/1, 3/1 and 0/1). The mass transport properties of PU scaffolds including hydraulic permeability and glucose diffusivity were also measured. Furthermore, the relationships between the porosity and mass transport and mechanical properties of porous PU scaffold were systemically investigated. The results demonstrated that porosity is a key parameter which governs both mass transport and mechanical properties of porous PU scaffolds. With similar pore sizes, the mass transport and mechanical properties of porous PU scaffold can be described as single functions of porosity regardless of initial PU concentration. The relationships between scaffold porosity and properties can be utilized to facilitate porous PU scaffold fabrication with specific mass transport and mechanical properties. The systematic approach established in this study can be applied to characterization of other biomaterials for scaffold design and fabrication.

  1. Kinematical properties of coronal mass ejections

    NASA Astrophysics Data System (ADS)

    Temmer, M.

    2016-11-01

    Coronal mass ejections (CMEs) are the most dynamic phenomena in our solar system. They abruptly disrupt the continuous outflow of solar wind by expelling huge clouds of magnetized plasma into interplanetary space with velocities enabling to cross the Sun-Earth distance within a few days. Earth-directed CMEs may cause severe geomagnetic storms when their embedded magnetic fields and the shocks ahead compress and reconnect with the Earth's magnetic field. The transit times and impacts in detail depend on the initial CME velocity, size, and mass, as well as on the conditions and coupling processes with the ambient solar wind flow in interplanetary space. The observed CME parameters may be severely affected by projection effects and the constant changing environmental conditions are hard to derive. This makes it difficult to fully understand the physics behind CME evolution, preventing to do a reliable forecast of Earth-directed events. This short review focusing on observational data, shows recent methods which were developed to derive the CME kinematical profile for the entire Sun-Earth distance range as well as studies which were performed to shed light on the physical processes that CMEs encounter when propagating from Sun to Earth.

  2. Geometrical Properties of Coronal Mass Ejections

    NASA Astrophysics Data System (ADS)

    Cremades, Hebe; Bothmer, Volker

    Based on the SOHO/LASCO dataset, a collection of "structured" coronal mass ejections (CMEs) has been compiled within the period 1996-2002, in order to analyze their three-dimensional configuration. These CME events exhibit white-light fine structures, likely indicative of their possible 3D topology. From a detailed investigation of the associated low coronal and photospheric source regions, a generic scheme has been deduced, which considers the white-light topology of a CME projected in the plane of the sky as being primarily dependent on the orientation and position of the source region's neutral line on the solar disk. The obtained results imply that structured CMEs are essentially organized along a symmetry axis, in a cylindrical manner. The measured dimensions of the cylinder's base and length yield a ratio of 1.6. These CMEs seem to be better approximated by elliptic cones, rather than by the classical ice cream cone, characterized by a circular cross section.

  3. Immunosuppressive and anti-inflammatory properties of engineered nanomaterials.

    PubMed

    Ilinskaya, A N; Dobrovolskaia, M A

    2014-09-01

    Nanoparticle interactions with various components of the immune system are determined by their physicochemical properties such as size, charge, hydrophobicity and shape. Nanoparticles can be engineered to either specifically target the immune system or to avoid immune recognition. Nevertheless, identifying their unintended impacts on the immune system and understanding the mechanisms of such accidental effects are essential for establishing a nanoparticle's safety profile. While immunostimulatory properties have been reviewed before, little attention in the literature has been given to immunosuppressive and anti-inflammatory properties. The purpose of this review is to fill this gap. We will discuss intended immunosuppression achieved by either nanoparticle engineering, or the use of nanoparticles to carry immunosuppressive or anti-inflammatory drugs. We will also review unintended immunosuppressive properties of nanoparticles per se and consider how such properties could be either beneficial or adverse.

  4. Comparisons of rational engineering correlations of thermophoretically-augmented particle mass transfer with STAN5-predictions for developing boundary layers

    NASA Technical Reports Server (NTRS)

    Gokoglu, S. A.; Rosner, D. E.

    1984-01-01

    Modification of the code STAN5 to properly include thermophoretic mass transport, and examination of selected test cases developing boundary layers which include variable properties, viscous dissipation, transition to turbulence and transpiration cooling. Under conditions representative of current and projected GT operation, local application of St(M)/St(M),o correlations evidently provides accurate and economical engineering design predictions, especially for suspended particles characterized by Schmidt numbers outside of the heavy vapor range.

  5. ENVIRONMENTAL DEPENDENCE OF OTHER GALAXY PROPERTIES FOR HIGH STELLAR MASS AND LOW STELLAR MASS GALAXIES

    SciTech Connect

    Deng Xinfa; Wen Xiaoqing; Xu Jianying; Ding Yingping; Huang Tong

    2010-06-10

    At a stellar mass of 3 x 10{sup 10} M {sub {Theta}} we divide the volume-limited Main galaxy sample of the Sloan Digital Sky Survey Data Release 6 (SDSS DR6) into two distinct families and explore the environmental dependence of galaxy properties for High Stellar Mass (HSM) and Low Stellar Mass (LSM) galaxies. It is found that for HSM and LSM galaxies, the environmental dependence of some typical galaxy properties, such as color, morphologies, and star formation activities, is still very strong, which at least shows that the stellar mass is not fundamental in correlations between galaxy properties and the environment. We also note that the environmental dependence of the size for HSM and LSM galaxies is fairly weak, which is mainly due to the galaxy size being insensitive to environment.

  6. Aircraft Structural Mass Property Prediction Using Conceptual-Level Structural Analysis

    NASA Technical Reports Server (NTRS)

    Sexstone, Matthew G.

    1998-01-01

    This paper describes a methodology that extends the use of the Equivalent LAminated Plate Solution (ELAPS) structural analysis code from conceptual-level aircraft structural analysis to conceptual-level aircraft mass property analysis. Mass property analysis in aircraft structures has historically depended upon parametric weight equations at the conceptual design level and Finite Element Analysis (FEA) at the detailed design level. ELAPS allows for the modeling of detailed geometry, metallic and composite materials, and non-structural mass coupled with analytical structural sizing to produce high-fidelity mass property analyses representing fully configured vehicles early in the design process. This capability is especially valuable for unusual configuration and advanced concept development where existing parametric weight equations are inapplicable and FEA is too time consuming for conceptual design. This paper contrasts the use of ELAPS relative to empirical weight equations and FEA. ELAPS modeling techniques are described and the ELAPS-based mass property analysis process is detailed. Examples of mass property stochastic calculations produced during a recent systems study are provided. This study involved the analysis of three remotely piloted aircraft required to carry scientific payloads to very high altitudes at subsonic speeds. Due to the extreme nature of this high-altitude flight regime, few existing vehicle designs are available for use in performance and weight prediction. ELAPS was employed within a concurrent engineering analysis process that simultaneously produces aerodynamic, structural, and static aeroelastic results for input to aircraft performance analyses. The ELAPS models produced for each concept were also used to provide stochastic analyses of wing structural mass properties. The results of this effort indicate that ELAPS is an efficient means to conduct multidisciplinary trade studies at the conceptual design level.

  7. Aircraft Structural Mass Property Prediction Using Conceptual-Level Structural Analysis

    NASA Technical Reports Server (NTRS)

    Sexstone, Matthew G.

    1998-01-01

    This paper describes a methodology that extends the use of the Equivalent LAminated Plate Solution (ELAPS) structural analysis code from conceptual-level aircraft structural analysis to conceptual-level aircraft mass property analysis. Mass property analysis in aircraft structures has historically depended upon parametric weight equations at the conceptual design level and Finite Element Analysis (FEA) at the detailed design level ELAPS allows for the modeling of detailed geometry, metallic and composite materials, and non-structural mass coupled with analytical structural sizing to produce high-fidelity mass property analyses representing fully configured vehicles early in the design process. This capability is especially valuable for unusual configuration and advanced concept development where existing parametric weight equations are inapplicable and FEA is too time consuming for conceptual design. This paper contrasts the use of ELAPS relative to empirical weight equations and FEA. ELAPS modeling techniques are described and the ELAPS-based mass property analysis process is detailed Examples of mass property stochastic calculations produced during a recent systems study are provided This study involved the analysis of three remotely piloted aircraft required to carry scientific payloads to very high altitudes at subsonic speeds. Due to the extreme nature of this high-altitude flight regime,few existing vehicle designs are available for use in performance and weight prediction. ELAPS was employed within a concurrent engineering analysis process that simultaneously produces aerodynamic, structural, and static aeroelastic results for input to aircraft performance analyses. The ELAPS models produced for each concept were also used to provide stochastic analyses of wing structural mass properties. The results of this effort indicate that ELAPS is an efficient means to conduct multidisciplinary trade studies at the conceptual design level.

  8. Toward Mass Customization in the Age of Information: The Case for Open Engineering Systems

    NASA Technical Reports Server (NTRS)

    Simpson, Timothy W.; Lautenschlager, Uwe; Mistree, Farrokh

    1997-01-01

    In the Industrial Era, manufacturers used "dedicated" engineering systems to mass produce their products. In today's increasingly competitive markets, the trend is toward mass customization, something that becomes increasingly feasible when modern information technologies are used to create open engineering systems. Our focus is on how designers can provide enhanced product flexibility and variety (if not fully customized products) through the development of open engineering systems. After presenting several industrial examples, we anchor our new systems philosophy with two real engineering applications. We believe that manufacturers who adopt open systems will achieve competitive advantage in the Information Age.

  9. Physical properties of erupting plasma associated with coronal mass ejections

    NASA Astrophysics Data System (ADS)

    Lee, J.; Raymond, J. C.; Reeves, K. K.; Moon, Y.; Kim, K.

    2013-12-01

    We investigate the physical properties (temperature, density, and mass) of erupting plasma observed in X-rays and EUV, which are all associated with coronal mass ejections observed by SOHO/LASCO. The erupting plasmas are observed as absorption or emission features in the low corona. The absorption feature provides a lower limit to the cold mass while the emission feature provides an upper limit to the mass of observed plasma in X-ray and EUV. We compare the mass constraints for each temperature response and find that the mass estimates in EUV and XRT are smaller than the total mass in the coronagraph. Several events were observed by a few passbands in the X-rays, which allows us to determine the temperature of the eruptive plasma using a filter ratio method. The temperature of one event is estimated at about 8.6 MK near the top of the erupting plasma. This measurement is possibly an average temperature for higher temperature plasma because the XRT is more sensitive at higher temperatures. In addition, a few events show that the absorption features of a prominence or a loop change to emission features with the beginning of their eruptions in all EUV wavelengths of SDO/AIA, which indicates the heating of the plasma. By estimating the physical properties of the erupting plasmas, we discuss the heating of the plasmas associated with coronal mass ejections in the low corona.

  10. Engineering properties of Incoloy-903 and CTX-1

    NASA Technical Reports Server (NTRS)

    Ruff, P. E.

    1980-01-01

    Engineering properties of Incoloy-903 sheet and CTX-1 (high strength austentic Fe-Ni-Co alloy) bar are characterized in report. Report includes tables and plots of test data and photographs of microstructure of samples used. Two appendixes include specimen configuration and data collected from industrial survey.

  11. Materials with engineered mesoporosity for programmed mass transport

    NASA Astrophysics Data System (ADS)

    Gough, Dara V.

    Transport in nanostructured materials is of great interest for scientists in various fields, including molecular sequestration, catalysis, artificial photosynthesis and energy storage. This thesis will present work on the transport of molecular and ionic species in mesoporous materials (materials with pore sizes between 2 and 50 nm). Initially, discussion will focus on the synthesis of mesoporous ZnS nanorattles and the size selected mass transport of small molecules through the mesopores. Discussion will then shift of exploration of cation exchange and electroless plating of metals to alter the mesoporous hollow sphere (MHS) materials and properties. The focus of discussion will then shift to the transport of ions into and out of a hierarchically structured gold electrode. Finally, a model gamma-bactiophage was developed to study the electromigration of charged molecules into and out of a confined geometry. A catalytically active biomolecular species was encapsulated within the central cavity of ZnS MHS. Both the activity of the encapsulated enzyme and the size-selective transport through the wall of the MHS were verified through the use of a common fluorogen, hydrogen peroxide, and sodium azide. Additionally, the protection of the enzyme was shown through size-selected blocking of a protease. The mesoporous hollow sphere system introduces size-selectivity to catalyzed chemical reactions; future work may include variations in pore sizes, and pore wall chemical functionalization. The pore size in ZnS mesoporous hollow spheres is controlled between 2.5 and 4.1 nm through swelling of the lyotropic liquid crystal template. The incorporation of a swelling agent is shown to linearly vary the hexagonal lyotropic liquid crystalline phase, which templates the mesopores, while allowing the high fidelity synthesis of mesoporous hollow spheres. Fluorescnently labeled ssDNA was utilized as a probe to explore the change in mesopore permeability afforded by the swollen template

  12. Some engineering properties of cotton-phenolic laminates

    NASA Astrophysics Data System (ADS)

    Walsh, R. P.; Toplosky, V. J.

    2002-05-01

    Although cotton/phenolic laminates are commonly used at cryogenic temperatures as structural and insulating materials, the available low temperature materials properties data is limited. We have reviewed the existing low temperature database for cotton/phenolic and have identified areas of need. We have conducted a materials test program on the two common types (linen and canvas) of cotton/phenolic laminates to add to the existing database and to generate new data in areas where needed. Also included is a comparison of cotton/phenolic engineering properties to the properties of NEMA G-10 CR glass-cloth reinforced laminate. The properties studied here are tensile and compressive strength, elastic modulus, shear properties and thermal expansion characteristics over the temperature range from 295 K to 4 K.

  13. Supermassive Black Hole Masses and Global Properties of Disk Galaxies

    NASA Astrophysics Data System (ADS)

    Castillo, Y. S.; Funes, J. G.; Díaz, R. J.

    2006-06-01

    Different scaling laws are known for the mass of supermassive black holes (M_{BH}): M_{BH}-σ M_{BH}-M_{Bulge}; M_{BH}-M_{DM}. We have reviewed these correlations for 17 disk galaxies and tried to find any correlation between M_{BH} and other disk properties (HI and H_2 masses, far infrared luminosity, star formation rate, etc.). The sample was taken from Marconi and Hunt (2003). For these galaxies we have done a search in the literature for the following properties: A) in the nucleus: star formation rates, and luminosities in Hα ; B) in the bulge: luminosity in B-band; C) in the disk: HI and H_2 total masses, total luminosities in X-ray, B band and far infrared, and total star formation rate. In this work we present the compiled data from the literature and the plots of M_{BH} against galaxy HI total mass, M_{BH} against galaxy H_2 total mass, and M_{BH} against disk blue luminosity. We did not find any evident correlation between the M_{BH} and the properties of the disk.

  14. Munition Mass Properties Measurement Procedures Using a Spin Balance Machine

    DTIC Science & Technology

    2015-03-09

    determines the mass properties, balance configurations, and balance specification(s) of live or inert munitions; namely, the Center of Gravity (CG...the Moment of Inertia (MOI), and the Product of Inertia (POI). 15. SUBJECT TERMS Center of Gravity Product of Inertia Moment of Inertia Spin...B-1 C. CENTER OF GRAVITY ...................................................... C-1 D

  15. New Rotary Table Providing Improved Mass Property Measurements

    NASA Astrophysics Data System (ADS)

    Messing, R.; Appolloni, M.; Sablerolle, S.; Tavares, A.; Hervieu, M.

    2014-06-01

    ESA Test Centre at ESTEC, Noordwijk is a unique place in Europe, which is geared to perform environmental tests on large spacecraft at system level. The Test Centre includes the whole environmental facilities family: shakers, acoustic chamber, mass properties measurement facilities, electro-magnetic compatibility facilities and thermal vacuum chambers.Center of gravity (CoG) measurements require at least two force measurements in combination with a mass measurement to determine the CoG in the horizontal x-y plane. To achieve more quickly two or more orientations of the specimen with respect to the force cell the Test Centre implemented a rotary table on top of its W50/M6 mass property machine. This paper focuses on the acceptance and implementation of the rotary table and how by its use the CoG measurements could be improved in terms of measurement time, measurement uncertainty and measurement reliability.

  16. Quadrotor Control in the Presence of Unknown Mass Properties

    NASA Astrophysics Data System (ADS)

    Duivenvoorden, Rikky Ricardo Petrus Rufino

    Quadrotor UAVs are popular due to their mechanical simplicity, as well as their capability to hover and vertically take-off and land. As applications diversify, quadrotors are increasingly required to operate under unknown mass properties, for example as a multirole sensor platform or for package delivery operations. The work presented here consists of the derivation of a generalized quadrotor dynamic model without the typical simplifying assumptions on the first and second moments of mass. The maximum payload capacity of a quadrotor in hover, and the observability of the unknown mass properties are discussed. A brief introduction of L1 adaptive control is provided, and three different L 1 adaptive controllers were designed for the Parrot AR.Drone quadrotor. Their tracking and disturbance rejection performance was compared to the baseline nonlinear controller in experiments. Finally, the results of the combination of L1 adaptive control with iterative learning control are presented, showing high performance trajectory tracking under uncertainty.

  17. COMPREHENSIVE ANALYSIS OF CORONAL MASS EJECTION MASS AND ENERGY PROPERTIES OVER A FULL SOLAR CYCLE

    SciTech Connect

    Vourlidas, A.; Howard, R. A.; Esfandiari, E.; Patsourakos, S.; Yashiro, S.; Michalek, G.

    2010-10-20

    The LASCO coronagraphs, in continuous operation since 1995, have observed the evolution of the solar corona and coronal mass ejections (CMEs) over a full solar cycle with high-quality images and regular cadence. This is the first time that such a data set becomes available and constitutes a unique resource for the study of CMEs. In this paper, we present a comprehensive investigation of the solar cycle dependence on the CME mass and energy over a full solar cycle (1996-2009) including the first in-depth discussion of the mass and energy analysis methods and their associated errors. Our analysis provides several results worthy of further studies. It demonstrates the possible existence of two event classes: 'normal' CMEs reaching constant mass for >10 R{sub sun} and {sup p}seudo{sup -}CMEs which disappear in the C3 field of view. It shows that the mass and energy properties of CME reach constant levels and therefore should be measured only above {approx}10 R{sub sun}. The mass density (g/R {sup 2}{sub sun}) of CMEs varies relatively little (< order of magnitude) suggesting that the majority of the mass originates from a small range in coronal heights. We find a sudden reduction in the CME mass in mid-2003 which may be related to a change in the electron content of the large-scale corona and we uncover the presence of a 6 month periodicity in the ejected mass from 2003 onward.

  18. Game-theory-based search engine to automate the mass assignment in complex native electrospray mass spectra.

    PubMed

    Tseng, Yao-Hsin; Uetrecht, Charlotte; Yang, Shih-Chieh; Barendregt, Arjan; Heck, Albert J R; Peng, Wen-Ping

    2013-12-03

    Electrospray ionization coupled to native mass spectrometry (MS) has evolved into an important tool in structural biology to decipher the composition of protein complexes. However, the mass analysis of heterogeneous protein assemblies is hampered because of their overlapping charge state distributions, fine structure, and peak broadening. To facilitate the mass analysis, it is of importance to automate preprocessing raw mass spectra, assigning ion series to peaks and deciphering the subunit compositions. So far, the automation of preprocessing raw mass spectra has not been accomplished; Massign was introduced to simplify data analysis and decipher the subunit compositions. In this study, we develop a search engine, AutoMass, to automatically assign ion series to peaks without any additional user input, for example, limited ranges of charge states or ion mass. AutoMass includes an ion intensity-dependent method to check for Gaussian distributions of ion series and an ion intensity-independent method to address highly overlapping and non-Gaussian distributions. The minimax theorem from game theory is adopted to define the boundaries. With AutoMass, the boundaries of ion series in the well-resolved tandem mass spectra of the hepatitis B virus (HBV) capsids and those of the mass spectrum from CRISPR-related cascade protein complex are accurately assigned. Theoretical and experimental HBV ion masses are shown in agreement up to ~0.03%. The analysis is finished within a minute on a regular workstation. Moreover, less well-resolved mass spectra, for example, complicated multimer mass spectra and norovirus capsid mass spectra at different levels of desolvation, are analyzed. In sum, this first-ever fully automatic program reveals the boundaries of overlapping ion peak series and can further aid developing high-throughput native MS and top-down proteomics.

  19. Impact of thermal energy storage properties on solar dynamic space power conversion system mass

    NASA Technical Reports Server (NTRS)

    Juhasz, Albert J.; Coles-Hamilton, Carolyn E.; Lacy, Dovie E.

    1987-01-01

    A 16 parameter solar concentrator/heat receiver mass model is used in conjunction with Stirling and Brayton Power Conversion System (PCS) performance and mass computer codes to determine the effect of thermal energy storage (TES) material property changes on overall PCS mass as a function of steady state electrical power output. Included in the PCS mass model are component masses as a function of thermal power for: concentrator, heat receiver, heat exchangers (source unless integral with heat receiver, heat sink, regenerator), heat engine units with optional parallel redundancy, power conditioning and control (PC and C), PC and C radiator, main radiator, and structure. Critical TES properties are: melting temperature, heat of fusion, density of the liquid phase, and the ratio of solid-to-liquid density. Preliminary results indicate that even though overall system efficiency increases with TES melting temperature up to 1400 K for concentrator surface accuracies of 1 mrad or better, reductions in the overall system mass beyond that achievable with lithium fluoride (LiF) can be accomplished only if the heat of fusion is at least 800 kJ/kg and the liquid density is comparable to that of LiF (1800 kg/cu m).

  20. Impact of thermal energy storage properties on solar dynamic space power conversion system mass

    NASA Technical Reports Server (NTRS)

    Juhasz, Albert J.; Coles-Hamilton, Carolyn E.; Lacy, Dovie E.

    1987-01-01

    A 16 parameter solar concentrator/heat receiver mass model is used in conjunction with Stirling and Brayton Power Conversion System (PCS) performance and mass computer codes to determine the effect of thermal energy storage (TES) material property changes on overall PCS mass as a function of steady state electrical power output. Included in the PCS mass model are component masses as a function of thermal power for: concentrator, heat receiver, heat exchangers (source unless integral with heat receiver, heat sink, regenerator), heat engine units with optional parallel redundancy, power conditioning and control (PC and C), PC and C radiator, main radiator, and structure. Critical TES properties are: melting temperature, heat of fusion, density of the liquid phase, and the ratio of solid-to-liquid density. Preliminary results indicate that even though overalll system efficiency increases with TES melting temperature up to 1400 K for concentrator surface accuracies of 1 mrad or better, reductions in the overall system mass beyond that achievable with lithium fluoride (LiF) can be accomplished only if the heat of fusion is at least 800 kJ/kg and the liquid density is comparable to that of LiF (1880 kg/cu m.

  1. Effects of functional group mass variance on vibrational properties and thermal transport in graphene

    NASA Astrophysics Data System (ADS)

    Lindsay, L.; Kuang, Y.

    2017-03-01

    Intrinsic thermal resistivity critically depends on features of phonon dispersions dictated by harmonic interatomic forces and masses. Here we present the effects of functional group mass variance on vibrational properties and thermal conductivity (κ ) of functionalized graphene from first-principles calculations. We use graphane, a buckled graphene backbone with covalently bonded hydrogen atoms on both sides, as the base material and vary the mass of the hydrogen atoms to simulate the effect of mass variance from other functional groups. We find nonmonotonic behavior of κ with increasing mass of the functional group and an unusual crossover from acoustic-dominated to optic-dominated thermal transport behavior. We connect this crossover to changes in the phonon dispersion with varying mass which suppress acoustic phonon velocities, but also give unusually high velocity optic modes. Further, we show that out-of-plane acoustic vibrations contribute significantly more to thermal transport than in-plane acoustic modes despite breaking of a reflection-symmetry-based scattering selection rule responsible for their large contributions in graphene. This work demonstrates the potential for manipulation and engineering of thermal transport properties in two-dimensional materials toward targeted applications.

  2. Effects of functional group mass variance on vibrational properties and thermal transport in graphene

    DOE PAGES

    Lindsay, L.; Kuang, Y.

    2017-03-13

    Intrinsic thermal resistivity critically depends on features of phonon dispersions dictated by harmonic interatomic forces and masses. We present the effects of functional group mass variance on vibrational properties and thermal conductivity (κ ) of functionalized graphene from first principles calculations. We also use graphane, a buckled graphene backbone with covalently bonded Hydrogen atoms on both sides, as the base material and vary the mass of the Hydrogen atoms to simulate the effect of mass variance from other functional groups. We find non-monotonic behavior of κ with increasing mass of the functional group and an unusual cross-over from acoustic-dominated tomore » optic-dominated thermal transport behavior. We connect this cross-over to changes in the phonon dispersion with varying mass which suppress acoustic phonon velocities, but also give unusually high velocity optic modes. Further, we show that out-of-plane acoustic vibrations contribute significantly more to thermal transport than in-plane acoustic modes despite breaking of a reflection symmetry based scattering selection rule responsible for their large contributions in graphene. Our work demonstrates the potential for manipulation and engineering of thermal transport properties in two dimensional materials toward targeted applications.« less

  3. Fuel property effects on engine combustion processes. Final report

    SciTech Connect

    Cernansky, N.P.; Miller, D.L.

    1995-04-27

    A major obstacle to improving spark ignition engine efficiency is the limitations on compression ratio imposed by tendency of hydrocarbon fuels to knock (autoignite). A research program investigated the knock problem in spark ignition engines. Objective was to understand low and intermediate temperature chemistry of combustion processes relevant to autoignition and knock and to determine fuel property effects. Experiments were conducted in an optically and physically accessible research engine, static reactor, and an atmospheric pressure flow reactor (APFR). Chemical kinetic models were developed for prediction of species evolution and autoignition behavior. The work provided insight into low and intermediate temperature chemistry prior to autoignition of n-butane, iso-butane, n-pentane, 1-pentene, n-heptane, iso-octane and some binary blends. Study of effects of ethers (MTBE, ETBE, TAME and DIPE ) and alcohols (methanol and ethanol) on the oxidation and autoignition of primary reference fuel (PRF) blends.

  4. Tissue-engineered cartilage with inducible and tunable immunomodulatory properties.

    PubMed

    Glass, Katherine A; Link, Jarrett M; Brunger, Jonathan M; Moutos, Franklin T; Gersbach, Charles A; Guilak, Farshid

    2014-07-01

    The pathogenesis of osteoarthritis is mediated in part by inflammatory cytokines including interleukin-1 (IL-1), which promote degradation of articular cartilage and prevent human mesenchymal stem cell (MSC) chondrogenesis. In this study, we combined gene therapy and functional tissue engineering to develop engineered cartilage with immunomodulatory properties that allow chondrogenesis in the presence of pathologic levels of IL-1 by inducing overexpression of IL-1 receptor antagonist (IL-1Ra) in MSCs via scaffold-mediated lentiviral gene delivery. A doxycycline-inducible vector was used to transduce MSCs in monolayer or within 3D woven PCL scaffolds to enable tunable IL-1Ra production. In the presence of IL-1, IL-1Ra-expressing engineered cartilage produced cartilage-specific extracellular matrix, while resisting IL-1-induced upregulation of matrix metalloproteinases and maintaining mechanical properties similar to native articular cartilage. The ability of functional engineered cartilage to deliver tunable anti-inflammatory cytokines to the joint may enhance the long-term success of therapies for cartilage injuries or osteoarthritis.

  5. Immunosuppressive and anti-inflammatory properties of engineered nanomaterials

    PubMed Central

    Ilinskaya, A N; Dobrovolskaia, M A

    2014-01-01

    Nanoparticle interactions with various components of the immune system are determined by their physicochemical properties such as size, charge, hydrophobicity and shape. Nanoparticles can be engineered to either specifically target the immune system or to avoid immune recognition. Nevertheless, identifying their unintended impacts on the immune system and understanding the mechanisms of such accidental effects are essential for establishing a nanoparticle's safety profile. While immunostimulatory properties have been reviewed before, little attention in the literature has been given to immunosuppressive and anti-inflammatory properties. The purpose of this review is to fill this gap. We will discuss intended immunosuppression achieved by either nanoparticle engineering, or the use of nanoparticles to carry immunosuppressive or anti-inflammatory drugs. We will also review unintended immunosuppressive properties of nanoparticles per se and consider how such properties could be either beneficial or adverse. Linked Articles This article is part of a themed section on Nanomedicine. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2014.171.issue-17 PMID:24724793

  6. Mass Property Measurements of the Mars Science Laboratory Rover

    NASA Technical Reports Server (NTRS)

    Fields, Keith

    2012-01-01

    The NASA/JPL Mars Science Laboratory (MSL) spacecraft mass properties were measured on a spin balance table prior to launch. This paper discusses the requirements and issues encountered with the setup, qualification, and testing using the spin balance table, and the idiosyncrasies encountered with the test system. The final mass measurements were made in the Payload Hazardous Servicing Facility (PHSF) at Kennedy Space Center on the fully assembled and fueled spacecraft. This set of environmental tests required that the control system for the spin balance machine be at a remote location, which posed additional challenges to the operation of the machine

  7. Selected engineering properties and applications of EPS geofoam

    NASA Astrophysics Data System (ADS)

    Elragi, Ahmed Fouad

    Expanded polystyrene (EPS) geofoam is a lightweight material that has been used in engineering applications since at least the 1950s. Its density is about a hundredth of that of soil. It has good thermal insulation properties with stiffness and compression strength comparable to medium clay. It is utilized in reducing settlement below embankments, sound and vibration damping, reducing lateral pressure on substructures, reducing stresses on rigid buried conduits and related applications. This study starts with an overview on EPS geofoam. EPS manufacturing processes are described followed by a review of engineering properties found in previous research work done so far. Standards and design manuals applicable to EPS are presented. Selected EPS geofoam-engineering applications are discussed with examples. State-of-the-art of experimental work is done on different sizes of EPS specimens under different loading rates for better understanding of the behavior of the material. The effects of creep, sample size, strain rate and cyclic loading on the stress strain response are studied. Equations for the initial modulus and the strength of the material under compression for different strain rates are presented. The initial modulus and Poisson's ratio are discussed in detail. Sample size effect on creep behavior is examined. Three EPS projects are shown in this study. The creep behavior of the largest EPS geofoam embankment fill is shown. Results from laboratory tests, mathematical modeling and field records are compared to each other. Field records of a geofoam-stabilized slope are compared to finite difference analysis results. Lateral stress reduction on an EPS backfill retaining structure is analyzed. The study ends with a discussion on two promising properties of EPS geofoam. These are the damping ability and the compressibility of this material. Finite element analysis, finite difference analysis and lab results are included in this discussion. The discussion with the

  8. Determination of PM mass emissions from an aircraft turbine engine using particle effective density

    NASA Astrophysics Data System (ADS)

    Durdina, L.; Brem, B. T.; Abegglen, M.; Lobo, P.; Rindlisbacher, T.; Thomson, K. A.; Smallwood, G. J.; Hagen, D. E.; Sierau, B.; Wang, J.

    2014-12-01

    Inventories of particulate matter (PM) emissions from civil aviation and air quality models need to be validated using up-to-date measurement data corrected for sampling artifacts. We compared the measured black carbon (BC) mass and the total PM mass determined from particle size distributions (PSD) and effective density for a commercial turbofan engine CFM56-7B26/3. The effective density was then used to calculate the PM mass losses in the sampling system. The effective density was determined using a differential mobility analyzer and a centrifugal particle mass analyzer, and increased from engine idle to take-off by up to 60%. The determined mass-mobility exponents ranged from 2.37 to 2.64. The mean effective density determined by weighting the effective density distributions by PM volume was within 10% of the unit density (1000 kg/m3) that is widely assumed in aircraft PM studies. We found ratios close to unity between the PM mass determined by the integrated PSD method and the real-time BC mass measurements. The integrated PSD method achieved higher precision at ultra-low PM concentrations at which current mass instruments reach their detection limit. The line loss model predicted ∼60% PM mass loss at engine idle, decreasing to ∼27% at high thrust. Replacing the effective density distributions with unit density lead to comparable estimates that were within 20% and 5% at engine idle and high thrust, respectively. These results could be used for the development of a robust method for sampling loss correction of the future PM emissions database from commercial aircraft engines.

  9. Mechanical Properties of Mass Concrete at Early Ages

    DTIC Science & Technology

    1991-08-01

    material properties during the time that concrete is undergoing the greatest amount of thermal activity and physical change (i.e. early ages, less than 3...Type II, low alkali (LA) portland cement meeting ASTM C 150 and a Class C fly ash meeting ASTM C 618 [11 i]. The fine aggregate was a natural sand...usually require that specially developed or modified models be used. It should also be noted that the use- of high percentages of pozzolans in mass

  10. Engineering and Design: Rock Mass Classification Data Requirements for Rippability

    DTIC Science & Technology

    2007-11-02

    geomechanics classification system (reference ~a(l))~ Bieniawski proposed the geomechanics classification system (RMR) to rate a rock mass by assigning...Weaver (bibliography 3b(l)) proposed a rippability rating chart based upon a modification of the geomechanics rating system; a similar chart is...as used in the geomechanics rating system. 9. Correlation with Tractor Size. Rippability for a given tractor selectlon 1s correlated with he total

  11. Frequency Shift During Mass Properties Testing Using Compound Pendulum Method

    NASA Technical Reports Server (NTRS)

    Wolfe, David; Regan, Chris

    2012-01-01

    During mass properties testing on the X-48B Blended Wing Body aircraft (The Boeing Company, Chicago, Illinois) at the National Aeronautics and Space Administration Dryden Flight Research Center, Edwards, California, large inertia measurement errors were observed in results from compound pendulum swings when compared to analytical models. By comparing periods of oscillations as measured from an average over the test period versus the period of each oscillation, it was noticed that the frequency of oscillation was shifting significantly throughout the test. This phenomenon was only noticed during compound pendulum swings, and not during bifilar pendulum swings. The frequency shift was only visible upon extensive data analysis of the frequency for each oscillation, and did not appear in averaged frequency data over the test period. Multiple test articles, test techniques, and hardware setups were used in attempts to eliminate or identify the cause of the frequency shift. Plotting the frequency of oscillation revealed a region of minimal shift that corresponded to a larger amplitude range. This region of minimal shift provided the most accurate results compared to a known test article; however, the amplitudes that produce accurate inertia measurements are amplitudes larger than those generally accepted in mass properties testing. This paper examines two case studies of the frequency shift, using mass properties testing performed on a dummy test article, and on the X-48B Blended Wing Body aircraft.

  12. Engineering Synergy: Energy and Mass Transport in Hybrid Nanomaterials.

    PubMed

    Cho, Eun Seon; Coates, Nelson E; Forster, Jason D; Ruminski, Anne M; Russ, Boris; Sahu, Ayaskanta; Su, Norman C; Yang, Fan; Urban, Jeffrey J

    2015-10-14

    An emerging class of materials that are hybrid in nature is propelling a technological revolution in energy, touching many fundamental aspects of energy-generation, storage, and conservation. Hybrid materials combine classical inorganic and organic components to yield materials that manifest new functionalities unattainable in traditional composites or other related multicomponent materials, which have additive function only. This Research News article highlights the exciting materials design innovations that hybrid materials enable, with an eye toward energy-relevant applications involving charge, heat, and mass transport.

  13. Engineering the Dynamic Properties of Protein Networks through Sequence Variation

    PubMed Central

    2016-01-01

    The dynamic behavior of macromolecular networks dominates the mechanical properties of soft materials and influences biological processes at multiple length scales. In hydrogels prepared from self-assembling artificial proteins, stress relaxation and energy dissipation arise from the transient character of physical network junctions. Here we show that subtle changes in sequence can be used to program the relaxation behavior of end-linked networks of engineered coiled-coil proteins. Single-site substitutions in the coiled-coil domains caused shifts in relaxation time over 5 orders of magnitude as demonstrated by dynamic oscillatory shear rheometry and stress relaxation measurements. Networks with multiple relaxation time scales were also engineered. This work demonstrates how time-dependent mechanical responses of macromolecular materials can be encoded in genetic information. PMID:27924309

  14. Bound nucleons have unique masses that govern elemental properties

    NASA Astrophysics Data System (ADS)

    Pamfiloff, Eugene

    2005-07-01

    It is known that measured binding energies associated with elements require equivalent energy to break the nuclear bond of a nucleus. Based upon the proposals contained in recent published works [1] [2] and with support from experimental high-energy data, it can be shown that a portion of listed binding energies are attributable to bound nucleons having a unique mass for every element. The figures show, relative to the hydrogen proton, that of the: a) 1.112 MeV binding energy per nucleon for 2H, 44% or 0.486 MeV represents a change in mass (δm) for the proton or neutron; b) of 5.629 MeV binding energy per nucleon for 7Li, 87% or 4.890 MeV represents a change of mass for each nucleon; c) likewise, 56Fe has 8.811 MeV binding energy per nucleon and of this 92% or 8.119 MeV represents a change in mass for each nucleon, and 232Th has 7.639 MeV binding energy per nucleon and of this, 90% or 6.848 MeV represents a change in mass for each nucleon. This demonstrates that the nucleons of each element have unique masses. It has been shown that if three protons are removed from 82Pb the result is not 79Au; therefore, we conclude and predict that in addition to the Z number, elemental properties are determined by the unique proton and neutron masses for each element. mailto:megforce@physast.uga.edumegforce@physast.uga.edu [1] ``The Order of the Forces'', [2] ``The Geatron Nuclear Model''

  15. Bound nucleons have unique masses that govern elemental properties

    NASA Astrophysics Data System (ADS)

    Pamfiloff, Eugene

    2005-04-01

    It is know that measured binding energies associated with elements require equivalent energy to break the nuclear bond of a nucleus. Based upon the proposals contained in a recent published work [1] and with support from experimental high-energy data, it can be shown that a portion of listed binding energies are attributed to bound nucleons having a unique mass for every element. The figures show, relative to the hydrogen proton, that of the: a) 1.112 MeV binding energy per nucleon for ^2H, 44% or 0.486 MeV represents a change in mass for the proton and neutron; b) of 5.629 MeV binding energy per nucleon for ^7Li, 87% or 4.890 MeV represents a change of mass for each nucleon; c) likewise, ^56Fe has 8.811 MeV binding energy per nucleon and of this 92% or 8.119 MeV represents a change in mass for each nucleon; and ^232Th has 7.639 MeV binding energy per nucleon and of this, 90% or 6.848 MeV represents a change in mass for each nucleon. This demonstrates that the nucleons of each element have unique masses. It can be shown that if three protons are removed from 82Pb the result is not 79Au. We conclude and predict that in addition to the Z number, elemental properties are determined by the unique proton and neutron masses for each element. [1] mailto:megforce@physast.uga.edumegforce@physast.uga.edu ``The Order of the Forces''

  16. Bound nucleons have unique masses that govern elemental properties

    NASA Astrophysics Data System (ADS)

    Pamfiloff, Eugene

    2005-03-01

    It is known that measured binding energies associated with elements require equivalent energy to break the nuclear bond of a nucleus. Based upon the proposals contained in recent published works [1] [2] and with support from experimental high-energy data, it can be shown that a portion of listed binding energies are attributable to bound nucleons having a unique mass for every element. The figures show, relative to the hydrogen proton, that of the: a) 1.112 MeV binding energy per nucleon for 2H, 44% or 0.486 MeV represents a change in mass (δm) for the proton or neutron; b) of 5.629 MeV binding energy per nucleon for 7Li, 87% or 4.890 MeV represents a change of mass for each nucleon; c) likewise, 56Fe has 8.811 MeV binding energy per nucleon and of this 92% or 8.119 MeV represents a change in mass for each nucleon, and 232Th has 7.639 MeV binding energy per nucleon and of this, 90% or 6.848 MeV represents a change in mass for each nucleon. This demonstrates that the nucleons of each element have unique masses. It has been shown that if three protons are removed from 82Pb the result is not 79Au; therefore, we conclude and predict that in addition to the Z number, elemental properties are determined by the unique proton and neutron masses for each element. mailto:megforce@physast.uga.edumegforce@physast.uga.edu [1] ``The Order of the Forces'', [2] ``The Geatron Nuclear Model''

  17. Some engineering properties of heavy concrete added silica fume

    SciTech Connect

    Akkaş, Ayşe; Başyiğit, Celalettin; Esen, Serap

    2013-12-16

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

  18. Some engineering properties of heavy concrete added silica fume

    NASA Astrophysics Data System (ADS)

    Akkaş, Ayşe; Başyiǧit, Celalettin; Esen, Serap

    2013-12-01

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

  19. Introduction of systems engineering and appropriate tools to a mass transit railway project

    SciTech Connect

    Allan, J.; Burdett, S.; Neal, P.; Williams, J.

    1996-12-01

    This paper describes the introduction of formal systems engineering including the introduction of a requirements management and modelling tool to a particular mass transit railway renewal project. The paper begins by explaining the nature of railway projects and the need, yet current scarcity, of application of formal systems engineering. It describes the specific project and the events leading up to the introduction of a systems engineering team into a project which would otherwise have not adopted formal systems engineering techniques. These are specifically the development of a code of practice and an initial feasibility study. It also describes the issues that have had to be resolved in this emerging application which include selection of a systems engineering tool, training, architecture and processes.

  20. Pharmaceutical and Toxicological Properties of Engineered Nanomaterials for Drug Delivery

    PubMed Central

    Palombo, Matthew; Deshmukh, Manjeet; Myers, Daniel; Gao, Jieming; Szekely, Zoltan; Sinko, Patrick J.

    2014-01-01

    Novel engineered nanomaterials (ENMs) are being developed to enhance therapy. The physicochemical properties of ENMs can be manipulated to control/direct biodistribution and target delivery, but these alterations also have implications for toxicity. It is well known that size plays a significant role in determining ENM effects since simply nanosizing a safe bulk material can render it toxic. However, charge, shape, rigidity, and surface modifications also have a significant influence on the biodistribution and toxicity of nanoscale drug delivery systems (NDDSs). In this review, NDDSs are considered in terms of platform technologies, materials, and physical properties that impart their pharmaceutical and toxicological effects. Moving forward, the development of safe and effective nanomedicines requires standardized protocols for determining the physical characteristics of ENMs as well as assessing their potential long-term toxicity. When such protocols are established, the remarkable promise of nanomedicine to improve the diagnosis and treatment of human disease can be fulfilled. PMID:24160695

  1. Quantitative ultrasonic evaluation of mechanical properties of engineering materials

    NASA Technical Reports Server (NTRS)

    Vary, A.

    1978-01-01

    Current progress in the application of ultrasonic techniques to nondestructive measurement of mechanical strength properties of engineering materials is reviewed. Even where conventional NDE techniques have shown that a part is free of overt defects, advanced NDE techniques should be available to confirm the material properties assumed in the part's design. There are many instances where metallic, composite, or ceramic parts may be free of critical defects while still being susceptible to failure under design loads due to inadequate or degraded mechanical strength. This must be considered in any failure prevention scheme that relies on fracture analysis. This review will discuss the availability of ultrasonic methods that can be applied to actual parts to assess their potential susceptibility to failure under design conditions.

  2. Mechanical properties of orthodontic wires made of super engineering plastic.

    PubMed

    Maekawa, Minami; Kanno, Zuisei; Wada, Takahiro; Hongo, Toshio; Doi, Hisashi; Hanawa, Takao; Ono, Takashi; Uo, Motohiro

    2015-01-01

    Most orthodontic equipment is fabricated from alloys such as stainless steel, Co-Cr and Ni-Ti because of their excellent elastic properties. In recent years, increasing esthetic demands, metal allergy and interference of metals with magnetic resonance imaging have driven the development of non-metallic orthodontic materials. In this study, we assessed the feasibility of using three super engineering plastics (PEEK, PES and PVDF) as orthodontic wires. PES and PVDF demonstrated excellent esthetics, although PEEK showed the highest bending strength and creep resistance. PEEK and PVDF showed quite low water absorption. Because of recent developments in coloration of PEEK, we conclude that PEEK has many advantageous properties that make it a suitable candidate for use as an esthetic metal-free orthodontic wire.

  3. Nanoindentation in crystal engineering: quantifying mechanical properties of molecular crystals.

    PubMed

    Varughese, Sunil; Kiran, M S R N; Ramamurty, Upadrasta; Desiraju, Gautam R

    2013-03-04

    Nanoindentation is a technique for measuring the elastic modulus and hardness of small amounts of materials. This method, which has been used extensively for characterizing metallic and inorganic solids, is now being applied to organic and metal-organic crystals, and has also become relevant to the subject of crystal engineering, which is concerned with the design of molecular solids with desired properties and functions. Through nanoindentation it is possible to correlate molecular-level properties such as crystal packing, interaction characteristics, and the inherent anisotropy with micro/macroscopic events such as desolvation, domain coexistence, layer migration, polymorphism, and solid-state reactivity. Recent developments and exciting opportunities in this area are highlighted in this Minireview.

  4. Properties of nuclear matter from macroscopic-microscopic mass formulas

    NASA Astrophysics Data System (ADS)

    Wang, Ning; Liu, Min; Ou, Li; Zhang, Yingxun

    2015-12-01

    Based on the standard Skyrme energy density functionals together with the extended Thomas-Fermi approach, the properties of symmetric and asymmetric nuclear matter represented in two macroscopic-microscopic mass formulas: Lublin-Strasbourg nuclear drop energy (LSD) formula and Weizsäcker-Skyrme (WS*) formula, are extracted through matching the energy per particle of finite nuclei. For LSD and WS*, the obtained incompressibility coefficients of symmetric nuclear matter are K∞ = 230 ± 11 MeV and 235 ± 11 MeV, respectively. The slope parameter of symmetry energy at saturation density is L = 41.6 ± 7.6 MeV for LSD and 51.5 ± 9.6 MeV for WS*, respectively, which is compatible with the liquid-drop analysis of Lattimer and Lim [4]. The density dependence of the mean-field isoscalar and isovector effective mass, and the neutron-proton effective masses splitting for neutron matter are simultaneously investigated. The results are generally consistent with those from the Skyrme Hartree-Fock-Bogoliubov calculations and nucleon optical potentials, and the standard deviations are large and increase rapidly with density. A better constraint for the effective mass is helpful to reduce uncertainties of the depth of the mean-field potential.

  5. Online Data Resources in Chemical Engineering Education: Impact of the Uncertainty Concept for Thermophysical Properties

    ERIC Educational Resources Information Center

    Kim, Sun Hyung; Kang, Jeong Won; Kroenlein, Kenneth; Magee, Joseph W.; Diky, Vladimir; Muzny, Chris D.; Kazakov, Andrei F.; Chirico, Robert D.; Frenkel, Michael

    2013-01-01

    We review the concept of uncertainty for thermophysical properties and its critical impact for engineering applications in the core courses of chemical engineering education. To facilitate the translation of developments to engineering education, we employ NIST Web Thermo Tables to furnish properties data with their associated expanded…

  6. Engineering of vault nanocapsules with enzymatic and fluorescent properties.

    PubMed

    Kickhoefer, Valerie A; Garcia, Yvette; Mikyas, Yeshi; Johansson, Erik; Zhou, Jing C; Raval-Fernandes, Sujna; Minoofar, Payam; Zink, Jeffrey I; Dunn, Bruce; Stewart, Phoebe L; Rome, Leonard H

    2005-03-22

    One of the central issues facing the emerging field of nanotechnology is cellular compatibility. Nanoparticles have been proposed for diagnostic and therapeutic applications, including drug delivery, gene therapy, biological sensors, and controlled catalysis. Viruses, liposomes, peptides, and synthetic and natural polymers have been engineered for these applications, yet significant limitations continue to prevent their use. Avoidance of the body's natural immune system, lack of targeting specificity, and the inability to control packaging and release are remaining obstacles. We have explored the use of a naturally occurring cellular nanoparticle known as the vault, which is named for its morphology with multiple arches reminiscent of cathedral ceilings. Vaults are 13-MDa ribonucleoprotein particles with an internal cavity large enough to sequester hundreds of proteins. Here, we report a strategy to target and sequester biologically active materials within the vault cavity. Attachment of a vault-targeting peptide to two proteins, luciferase and a variant of GFP, resulted in their sequestration within the vault cavity. The targeted proteins confer enzymatic and fluorescent properties on the recombinant vaults, both of which can be detected by their emission of light. The modified vaults are compatible with living cells. The ability to engineer vault particles with designed properties and functionalities represents an important step toward development of a biocompatible nanocapsule.

  7. Control System Upgrade for a Mass Property Measurement Facility

    NASA Technical Reports Server (NTRS)

    Chambers, William; Hinkle, R. Kenneth (Technical Monitor)

    2002-01-01

    The Mass Property Measurement Facility (MPMF) at the Goddard Space Flight Center has undergone modifications to ensure the safety of Flight Payloads and the measurement facility. The MPMF has been technically updated to improve reliability and increase the accuracy of the measurements. Modifications include the replacement of outdated electronics with a computer based software control system, the addition of a secondary gas supply in case of a catastrophic failure to the gas supply and a motor controlled emergency stopping feature instead of a hard stop.

  8. Morphology and Optical Properties of Black-Carbon Particles Relevant to Engine Emissions

    NASA Astrophysics Data System (ADS)

    Michelsen, H. A.; Bambha, R.; Dansson, M. A.; Schrader, P. E.

    2013-12-01

    Black-carbon particles are believed to have a large influence on climate through direct radiative forcing, reduction of surface albedo of snow and ice in the cryosphere, and interaction with clouds. The optical properties and morphology of atmospheric particles containing black carbon are uncertain, and characterization of black carbon resulting from engines emissions is needed. Refractory black-carbon particles found in the atmosphere are often coated with unburned fuel, sulfuric acid, water, ash, and other combustion by-products and atmospheric constituents. Coatings can alter the optical and physical properties of the particles and therefore change their optical properties and cloud interactions. Details of particle morphology and coating state can also have important effects on the interpretation of optical diagnostics. A more complete understanding of how coatings affect extinction, absorption, and incandescence measurements is needed before these techniques can be applied reliably to a wide range of particles. We have investigated the effects of coatings on the optical and physical properties of combustion-generated black-carbon particles using a range of standard particle diagnostics, extinction, and time-resolved laser-induced incandescence (LII) measurements. Particles were generated in a co-flow diffusion flame, extracted, cooled, and coated with oleic acid. The diffusion flame produces highly dendritic soot aggregates with similar properties to those produced in diesel engines, diffusion flames, and most natural combustion processes. A thermodenuder was used to remove the coating. A scanning mobility particle sizer (SMPS) was used to monitor aggregate sizes; a centrifugal particle mass analyzer (CPMA) was used to measure coating mass fractions, and transmission electron microscopy (TEM) was used to characterize particle morphologies. The results demonstrate important differences in optical measurements between coated and uncoated particles.

  9. New method for time-resolved diesel engine exhaust particle mass measurement.

    PubMed

    Lehmann, U; Niemelä, V; Mohr, M

    2004-11-01

    The Dekati mass monitor (DMM; Dekati Ltd., Finland), a relatively new real-time mass measurement instrument, was investigated in this project. In contrast to the existing gravimetric filter method also used as a standard for regulation purposes, this instrument provides second-by-second data on mass concentration in the engine exhaust gas. The principle of the DMM is based on particle charging, inertial and electrical size classification, and electrical detection of aerosol particles. This study focuses on the instrument's practical performance. Details on calibration and the theory of operation will be published elsewhere. The exhaust emissions of two heavy-duty engines complying with the Euro III emission standard were measured on a dynamic engine test bench. We looked atthe particle number and mass emissions of the engines in different transient test cycles and steady-state conditions. The ability to follow transient test cycles and the response times of the DMM were investigated. The aerosol mass concentration measured by the DMM was compared with the mass concentration obtained by the standard gravimetric filter method with Teflon-coated glass fiber filters. The total mass concentration (integral over the whole cycle) measured by the DMM is about 20% higher than that measured by the standard gravimetric filter method. The total mass concentration from the DMM was also compared with the volume concentration calculated from the electrical low-pressure impactor (ELPI) measurements. Correlations were made with other particle measuring systems. The DMM correlates very well with the particulate mass (R2 = 0.95) and exhibits good linearity and repeatability. The response time to a well-defined change in exhaust concentration was observed to be fast and stable. The DMM was able to follow transient test cycles and provides good results on a second-by-second basis. The instrument used in this study was still under development, and there is therefore no complete

  10. Kalman Filter for Mass Property and Thrust Identification (MMS)

    NASA Technical Reports Server (NTRS)

    Queen, Steven

    2015-01-01

    The Magnetospheric Multiscale (MMS) mission consists of four identically instrumented, spin-stabilized observatories, elliptically orbiting the Earth in a tetrahedron formation. For the operational success of the mission, on-board systems must be able to deliver high-precision orbital adjustment maneuvers. On MMS, this is accomplished using feedback from on-board star sensors in tandem with accelerometers whose measurements are dynamically corrected for errors associated with a spinning platform. In order to determine the required corrections to the measured acceleration, precise estimates of attitude, rate, and mass-properties is necessary. To this end, both an on-board and ground-based Multiplicative Extended Kalman Filter (MEKF) were formulated and implemented in order to estimate the dynamic and quasi-static properties of the spacecraft.

  11. Observed Properties of Exoplanets: Masses, Orbits, and Metallicities

    NASA Astrophysics Data System (ADS)

    Marcy, G.; Butler, R. P.; Fischer, D.; Vogt, S.; Wright, J. T.; Tinney, C. G.; Jones, H. R. A.

    We review the observed properties of exoplanets found by the Doppler technique that has revealed 152 planets to date. We focus on the ongoing 18-year survey of 1330 FGKM type stars at Lick, Keck, and the Anglo-Australian Telescopes that offers both uniform Doppler precision (3 m s-1) and long duration. The 104 planets detected in this survey have minimum masses (M sin i) as low as 6 MEarth, orbiting between 0.02 and 6 AU. The core-accretion model of planet formation is supported by four observations: 1) The mass distribution rises toward the lowest detectable masses, dN/dM ∝ M-1.0. 2) Stellar metallicity correlates strongly with the presence of planets. 3) One planet (1.3 MSat) has a massive rocky core, MCore ≈ 70 MEarth. 4) A super-Earth of ˜ 7 MEarth has been discovered. The distribution of semi-major axes rises from 0.3 -- 3.0 AU (dN/d log a) and extrapolation suggests that ˜12% of the FGK stars harbor gas-giant exoplanets within 20 AU. The median orbital eccentricity is < e > = 0.25, and even planets beyond 3 AU reside in eccentric orbits, suggesting that the circular orbits in our Solar System are unusual. The occurrence ``hot Jupiters'' within 0.1 AU of FGK stars is 1.2 ± 0.2%. Among stars with one planet, 14% have at least one additional planet, occasionally locked in resonances. Kepler and COROT will measure the occurrence of earth-sized planets. The Space Interferometry Mission (SIM) will detect planets with masses as low as 3 MEarth orbiting within 2 AU of stars within 10 pc, and it will measure masses, orbits, and multiplicity. The candidate rocky planets will be amenable to follow-up spectroscopy by the ``Terrestrial Planet Finder'' and Darwin.

  12. Uncertainty quantification of measured quantities for a HCCI engine: mass-average quantities and perofrmances

    SciTech Connect

    Petitpas, Guillaume; Whitesides, Russel

    2016-12-12

    UQHCCI_2 propagates the uncertainties of mass-average quantities (temperature, heat capacity ratio) and the output performances (IMEP, heat release, CA50 and RI) of a HCCI engine test bench using the pressure trace, and intake and exhaust molar fraction and IVC temperature distributions, as inputs (those inputs may be computed using another code UQHCCI_2, or entered independently).

  13. Reverse engineering nuclear properties from rare earth abundances in the r process

    NASA Astrophysics Data System (ADS)

    Mumpower, M. R.; McLaughlin, G. C.; Surman, R.; Steiner, A. W.

    2017-03-01

    The bulk of the rare earth elements are believed to be synthesized in the rapid neutron capture process or r process of nucleosynthesis. The solar r-process residuals show a small peak in the rare earths around A∼ 160, which is proposed to be formed dynamically during the end phase of the r process by a pileup of material. This abundance feature is of particular importance as it is sensitive to both the nuclear physics inputs and the astrophysical conditions of the main r process. We explore the formation of the rare earth peak from the perspective of an inverse problem, using Monte Carlo studies of nuclear masses to investigate the unknown nuclear properties required to best match rare earth abundance sector of the solar isotopic residuals. When nuclear masses are changed, we recalculate the relevant β-decay properties and neutron capture rates in the rare earth region. The feedback provided by this observational constraint allows for the reverse engineering of nuclear properties far from stability where no experimental information exists. We investigate a range of astrophysical conditions with this method and show how these lead to different predictions in the nuclear properties influential to the formation of the rare earth peak. We conclude that targeted experimental campaigns in this region will help to resolve the type of conditions responsible for the production of the rare earth nuclei, and will provide new insights into the longstanding problem of the astrophysical site(s) of the r process.

  14. Hygroscopic Properties of Aircraft Engine Exhaust Aerosol Produced From Traditional and Alternative Fuels

    NASA Astrophysics Data System (ADS)

    Moore, R.; Ziemba, L. D.; Beyersdorf, A. J.; Thornhill, K. L.; Winstead, E. L.; Crumeyrolle, S.; Chen, G.; Anderson, B. E.

    2012-12-01

    Aircraft emissions of greenhouse gases and aerosols constitute an important component of anthropogenic climate forcing, of which aerosol-cloud interactions remain poorly understood. It is currently thought that the ability of these aerosols to alter upper tropospheric cirrus cloud properties may produce radiative forcings many times larger than the impact of linear contrails alone and which may partially offset the impact of greenhouse gas emissions from aviation (Burkhardt and Karcher, Nature, 2011). Consequently, it is important to characterize the ability of these engine-emitted aerosol to act as cloud condensation nuclei (CCN) and ice nuclei (IN) to form clouds. While a number of studies in the literature have examined aerosol-cloud interactions for laboratory-generated soot or from aircraft engines burning traditional fuels, limited attention has been given to how switching to alternative jet fuels impacts the ability of engine-emitted aerosols to form clouds. The key to understanding these changes is the aerosol hygroscopicity. To address this need, the second NASA Alternative Aviation Fuel Experiment (AAFEX-II) was conducted in 2011 to examine the aerosol emissions from the NASA DC-8 under a variety of different engine power and fuel type conditions. Five fuel types were considered including traditional JP-8 fuel, synthetic Fischer-Tropsh (FT) fuel , sulfur-doped FT fuel (FTS) , hydrotreated renewable jet (HRJ) fuel, and a 50:50 blend of JP-8 with HRJ. Emissions were sampled from the DC-8 on the airport jetway at a distance of 145 meters downwind of the engine by a comprehensive suite of aerosol instrumentation that provided information on the aerosol concentration, size distribution, soot mass, and CCN activity. Concurrent measurements of carbon dioxide were used to account for plume dilution so that characteristic emissions indices could be determined. It is found that both engine power and fuel type significantly influence the hygroscopic properties of

  15. Evolution of In-Cylinder Diesel Engine Soot and Emission Characteristics Investigated with Online Aerosol Mass Spectrometry.

    PubMed

    Malmborg, V B; Eriksson, A C; Shen, M; Nilsson, P; Gallo, Y; Waldheim, B; Martinsson, J; Andersson, Ö; Pagels, J

    2017-02-07

    To design diesel engines with low environmental impact, it is important to link health and climate-relevant soot (black carbon) emission characteristics to specific combustion conditions. The in-cylinder evolution of soot properties over the combustion cycle and as a function of exhaust gas recirculation (EGR) was investigated in a modern heavy-duty diesel engine. A novel combination of a fast gas-sampling valve and a soot particle aerosol mass spectrometer (SP-AMS) enabled online measurements of the in-cylinder soot chemistry. The results show that EGR reduced the soot formation rate. However, the late cycle soot oxidation rate (soot removal) was reduced even more, and the net effect was increased soot emissions. EGR resulted in an accumulation of polycyclic aromatic hydrocarbons (PAHs) during combustion, and led to increased PAH emissions. We show that mass spectral and optical signatures of the in-cylinder soot and associated low volatility organics change dramatically from the soot formation dominated phase to the soot oxidation dominated phase. These signatures include a class of fullerene carbon clusters that we hypothesize represent less graphitized, C5-containing fullerenic (high tortuosity or curved) soot nanostructures arising from decreased combustion temperatures and increased premixing of air and fuel with EGR. Altered soot properties are of key importance when designing emission control strategies such as diesel particulate filters and when introducing novel biofuels.

  16. Structure-property relations in engineered semiconductor nanomaterials (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Hollingsworth, Jennifer A.; Htoon, Han

    2016-09-01

    Particle-size or `quantum-confinement' effects have been used for decades to tune semiconductor opto-electronic properties. More recently, particle size control as the primary means for properties control has been succeeded by nanoscale hetero-structuring. In this case, the nanosized particle is modified to include internal, nanoscale interfaces, generally defined by compositional variations that induce additional changes to semiconductor properties. These changes can entail enhancements to the size-induced properties as well as unexpected or `emergent' behaviors. Common structural motifs include enveloping a spherical semiconductor nanocrystal, i.e., a quantum dot, within a shell of a different composition. In this talk, I will discuss how solution-phase synthesis can be used to create these structures with precisely `engineered' complexity. Most notably, I will review our experiences with so-called `giant' quantum dots that, due to their internal nanoscale structure, exhibit a range of novel behaviors, including being non-blinking and non-photobleaching (Chen et al. J. Am. Chem. Soc. 2008, 130, 5026; Ghosh et al. J. Am. Chem. Soc. 2012, 134, 9634; Dennis et al. Nano Lett. 2012 12, 5545; Acharya et al. J. Am. Chem. Soc. 2015, 137, 3755), and remarkably efficient emitters of `multi-excitons' due to extreme suppression of Auger recombination (Mangum et al. Nanoscale 2014, 6, 3712; Gao et al. Adv. Optical Mater. 2015, 3, 39). I will discuss recent work extending non-blinking behavior to the blue/green and "dual-color" emission, and show how correlated optical/structural characterization can reveal new information regarding structure-property relations to guide new nanomaterials development (Orfield et al. ACS Nano, Article ASAP).

  17. Contribution of engineered nanomaterials physicochemical properties to mast cell degranulation

    NASA Astrophysics Data System (ADS)

    Johnson, Monica M.; Mendoza, Ryan; Raghavendra, Achyut J.; Podila, Ramakrishna; Brown, Jared M.

    2017-03-01

    The rapid development of engineered nanomaterials (ENMs) has grown dramatically in the last decade, with increased use in consumer products, industrial materials, and nanomedicines. However, due to increased manufacturing, there is concern that human and environmental exposures may lead to adverse immune outcomes. Mast cells, central to the innate immune response, are one of the earliest sensors of environmental insult and have been shown to play a role in ENM-mediated immune responses. Our laboratory previously determined that mast cells are activated via a non-FcεRI mediated response following silver nanoparticle (Ag NP) exposure, which was dependent upon key physicochemical properties. Using bone marrow-derived mast cells (BMMCs), we tested the hypothesis that ENM physicochemical properties influence mast cell degranulation. Exposure to 13 physicochemically distinct ENMs caused a range of mast degranulation responses, with smaller sized Ag NPs (5 nm and 20 nm) causing the most dramatic response. Mast cell responses were dependent on ENMs physicochemical properties such as size, apparent surface area, and zeta potential. Surprisingly, minimal ENM cellular association by mast cells was not correlated with mast cell degranulation. This study suggests that a subset of ENMs may elicit an allergic response and contribute to the exacerbation of allergic diseases.

  18. Contribution of engineered nanomaterials physicochemical properties to mast cell degranulation

    PubMed Central

    Johnson, Monica M.; Mendoza, Ryan; Raghavendra, Achyut J.; Podila, Ramakrishna; Brown, Jared M.

    2017-01-01

    The rapid development of engineered nanomaterials (ENMs) has grown dramatically in the last decade, with increased use in consumer products, industrial materials, and nanomedicines. However, due to increased manufacturing, there is concern that human and environmental exposures may lead to adverse immune outcomes. Mast cells, central to the innate immune response, are one of the earliest sensors of environmental insult and have been shown to play a role in ENM-mediated immune responses. Our laboratory previously determined that mast cells are activated via a non-FcεRI mediated response following silver nanoparticle (Ag NP) exposure, which was dependent upon key physicochemical properties. Using bone marrow-derived mast cells (BMMCs), we tested the hypothesis that ENM physicochemical properties influence mast cell degranulation. Exposure to 13 physicochemically distinct ENMs caused a range of mast degranulation responses, with smaller sized Ag NPs (5 nm and 20 nm) causing the most dramatic response. Mast cell responses were dependent on ENMs physicochemical properties such as size, apparent surface area, and zeta potential. Surprisingly, minimal ENM cellular association by mast cells was not correlated with mast cell degranulation. This study suggests that a subset of ENMs may elicit an allergic response and contribute to the exacerbation of allergic diseases. PMID:28262689

  19. Electrical engineering of the optical properties in silicene

    NASA Astrophysics Data System (ADS)

    Bao, Hairui; Guo, Junji; Liao, Wenhu; Zhao, Heping

    2015-02-01

    Based on the intersubband transition theorem of the semiconductors, we have theoretically investigated the optical properties of a three-terminal silicene-based device under the irradiation of a circularly polarized terahertz electromagnetic field. The system spin-orbit-coupled electronic structure may be engineered to topological insulated (TI) and band insulated (BI) state, respectively, by the staggered sublattice potential from the back-gate voltage. It has been demonstrated that the dielectric functions and optical absorption spectra from the TI spin-up and spin-down subbands behave redshift and blueshift, respectively, with the increase in the sublattice potential, while those from the BI spin-up and spin-down subbands have been proven to be continually blue-shifted with the staggered sublattice potential. The novel features may be useful in the design of the spintronic and optoelectronic devices based on silicene.

  20. The rheological properties of silated hydroxypropylmethylcellulose tissue engineering matrices.

    PubMed

    Fatimi, Ahmed; Tassin, Jean François; Quillard, Sophie; Axelos, Monique A V; Weiss, Pierre

    2008-02-01

    This paper describes the rheological properties of silated hydroxypropylmethylcellulose (HPMC-Si) used in biomaterials domain as a three-dimensional synthetic matrix for tissue engineering. The HPMC-Si is an HPMC grafted with 3-glycidoxypropyltrimethoxysilane (GPTMS). HPMC and HPMC-Si were studied. It is shown that although silanization reduces the hydrodynamic volume in dilute solution, it does not affect significantly the rheological behavior of the concentrated solutions. The HPMC-Si viscous solution (pH 12.8) cross-links by decreasing the pH using an acid buffer, since HPMC-Si solution transforms into an elastic state. The kinetics of cross-linking and final elastic properties is influenced by several parameters such as polymer concentration, pH and temperature. pH and temperature play an important role in the silanol condensation, mainly responsible for network formation. The study of the gelation process revealed the dependence of the final concentration of HPMC-Si hydrogel on cross-linking kinetics and viscoelastic properties. The percolation theory was applied to determine gel point and to discuss the dependence of storage (G') and loss (G'') moduli on frequency. Results showed that both G' and G'' exhibit a power-law behavior with an exponent (0.68) which extends over the entire frequency range. This method is the only one to characterize the time where a liquid viscous phase shifts to hydrogel with elastic properties. In this case it was about 23 min for a final pH of 7.4.

  1. Masses, Radii, and Cloud Properties of the HR 8799 Planets

    NASA Technical Reports Server (NTRS)

    Marley, Mark S.; Saumon, Didier; Cushing, Michael; Ackerman, Andrew S.; Fortney, Jonathan J.; Freedman, Richard

    2012-01-01

    The near-infrared colors of the planets directly imaged around the A star HR 8799 are much redder than most field brown dwarfs of the same effective temperature. Previous theoretical studies of these objects have compared the photometric and limited spectral data of the planets to the predictions of various atmosphere and evolution models and concluded that the atmospheres of planets b, c, and d are unusually cloudy or have unusual cloud properties. Most studies have also found that the inferred radii of some or all of the planets disagree with expectations of standard giant planet evolution models. Here we compare the available data to the predictions of our own set of atmospheric and evolution models that have been extensively tested against field L and T dwarfs, including the reddest L dwarfs. Unlike almost all previous studies we specify mutually self-consistent choices for effective temperature, gravity, cloud properties, and planetary radius. This procedure yields plausible and self-consistent values for the masses, effective temperatures, and cloud properties of all three planets. We find that the cloud properties of the HR 8799 planets are in fact not unusual but rather follow previously recognized trends including a gravity dependence on the temperature of the L to T spectral transition, some reasons for which we discuss. We find that the inferred mass of planet b is highly sensitive to the H and K band spectrum. Solutions for planets c and particularly d are less certain but are consistent with the generally accepted constraints on the age of the primary star and orbital dynamics. We also confirm that as for L and T dwarfs and solar system giant planets, non-equilibrium chemistry driven by atmospheric mixing is also important for these objects. Given the preponderance of data suggesting that the L to T spectral type transition is gravity dependent, we present a new evolution calculation that predicts cooling tracks on the near-infrared color

  2. The direct measurement of structural mass, stiffness and damping properties

    NASA Astrophysics Data System (ADS)

    Lee, H. G.; Dobson, B. J.

    1991-02-01

    A method is described for directly evaluating the spatial properties (i.e., mass, stiffness and damping) of a structure from experimentally measured frequency response data. The resulting structural model can be compared directly with an equivalent finite element idealization. The effects of model reduction, such as the Guyan method, which can be employed to ensure that the experimental and theoretical models contain comparable degrees of freedom, are discussed. It is shown that it is possible to detect regions within the structure at which differences exist between the experimental and theoretical models. Further, it is demonstrated that the resulting experimentally derived models can be used to predict the effects of structural modifications upon the frequency response behaviour of the structure.

  3. Mass Properties Measurement in the X-38 Project

    NASA Technical Reports Server (NTRS)

    Peterson, Wayne L.

    2004-01-01

    This paper details the techniques used in measuring the mass properties for the X-38 family of test vehicles. The X-38 Project was a NASA internal venture in which a series of test vehicles were built in order to develop a Crew Return Vehicle (CRV) for the International Space Station. Three atmospheric test vehicles and one spaceflight vehicle were built to develop the technologies required for a CRV. The three atmospheric test vehicles have undergone flight-testing by a combined team from the NASA Johnson Space Center and the NASA Dryden Flight Research Center. The flight-testing was performed at Edward's Air Force Base in California. The X-38 test vehicles are based on the X-24A, which flew in the '60s and '70s. Scaled Composites, Inc. of Mojave, California, built the airframes and the vehicles were outfitted at the NASA Johnson Space Center in Houston, Texas. Mass properties measurements on the atmospheric test vehicles included weight and balance by the three-point suspension method, four-point suspension method, three load cells on jackstands, and on three in-ground platform scales. Inertia measurements were performed as well in which Ixx, Iyy, Izz, and Ixz were obtained. This paper describes each technique and the relative merits of each. The proposed measurement methods for an X-38 spaceflight test vehicle will also be discussed. This vehicle had different measurement challenges, but integrated vehicle measurements were never conducted. The spaceflight test vehicle was also developed by NASA and was scheduled to fly on the Space Shuttle before the project was cancelled.

  4. Cooling system having reduced mass pin fins for components in a gas turbine engine

    DOEpatents

    Lee, Ching-Pang; Jiang, Nan; Marra, John J

    2014-03-11

    A cooling system having one or more pin fins with reduced mass for a gas turbine engine is disclosed. The cooling system may include one or more first surfaces defining at least a portion of the cooling system. The pin fin may extend from the surface defining the cooling system and may have a noncircular cross-section taken generally parallel to the surface and at least part of an outer surface of the cross-section forms at least a quartercircle. A downstream side of the pin fin may have a cavity to reduce mass, thereby creating a more efficient turbine airfoil.

  5. Oligomers modulate interfibril branching and mass transport properties of collagen matrices.

    PubMed

    Whittington, Catherine F; Brandner, Eric; Teo, Ka Yaw; Han, Bumsoo; Nauman, Eric; Voytik-Harbin, Sherry L

    2013-10-01

    Mass transport within collagen-based matrices is critical to tissue development, repair, and pathogenesis, as well as the design of next-generation tissue engineering strategies. This work shows how collagen precursors, specified by intermolecular cross-link composition, provide independent control of collagen matrix mechanical and transport properties. Collagen matrices were prepared from tissue-extracted monomers or oligomers. Viscoelastic behavior was measured in oscillatory shear and unconfined compression. Matrix permeability and diffusivity were measured using gravity-driven permeametry and integrated optical imaging, respectively. Both collagen types showed an increase in stiffness and permeability hindrance with increasing collagen concentration (fibril density); however, different physical property–concentration relationships were noted. Diffusivity was not affected by concentration for either collagen type over the range tested. In general, oligomer matrices exhibited a substantial increase in stiffness and only a modest decrease in transport properties when compared with monomer matrices prepared at the same concentration. The observed differences in viscoelastic and transport properties were largely attributed to increased levels of interfibril branching within oligomer matrices. The ability to relate physical properties to relevant microstructure parameters, including fibril density and interfibril branching, is expected to advance the understanding of cell–matrix signaling, as well as facilitate model-based prediction and design of matrix-based therapeutic strategies.

  6. Conductometric Sensor for Soot Mass Flow Detection in Exhausts of Internal Combustion Engines.

    PubMed

    Feulner, Markus; Hagen, Gunter; Müller, Andreas; Schott, Andreas; Zöllner, Christian; Brüggemann, Dieter; Moos, Ralf

    2015-11-13

    Soot sensors are required for on-board diagnostics (OBD) of automotive diesel particulate filters (DPF) to detect filter failures. Widely used for this purpose are conductometric sensors, measuring an electrical current or resistance between two electrodes. Soot particles deposit on the electrodes, which leads to an increase in current or decrease in resistance. If installed upstream of a DPF, the "engine-out" soot emissions can also be determined directly by soot sensors. Sensors were characterized in diesel engine real exhausts under varying operation conditions and with two different kinds of diesel fuel. The sensor signal was correlated to the actual soot mass and particle number, measured with an SMPS. Sensor data and soot analytics (SMPS) agreed very well, an impressing linear correlation in a double logarithmic representation was found. This behavior was even independent of the used engine settings or of the biodiesel content.

  7. Conductometric Sensor for Soot Mass Flow Detection in Exhausts of Internal Combustion Engines

    PubMed Central

    Feulner, Markus; Hagen, Gunter; Müller, Andreas; Schott, Andreas; Zöllner, Christian; Brüggemann, Dieter; Moos, Ralf

    2015-01-01

    Soot sensors are required for on-board diagnostics (OBD) of automotive diesel particulate filters (DPF) to detect filter failures. Widely used for this purpose are conductometric sensors, measuring an electrical current or resistance between two electrodes. Soot particles deposit on the electrodes, which leads to an increase in current or decrease in resistance. If installed upstream of a DPF, the “engine-out” soot emissions can also be determined directly by soot sensors. Sensors were characterized in diesel engine real exhausts under varying operation conditions and with two different kinds of diesel fuel. The sensor signal was correlated to the actual soot mass and particle number, measured with an SMPS. Sensor data and soot analytics (SMPS) agreed very well, an impressing linear correlation in a double logarithmic representation was found. This behavior was even independent of the used engine settings or of the biodiesel content. PMID:26580621

  8. A study of mass data storage technology for rocket engine data

    NASA Technical Reports Server (NTRS)

    Ready, John F.; Benser, Earl T.; Fritz, Bernard S.; Nelson, Scott A.; Stauffer, Donald R.; Volna, William M.

    1990-01-01

    The results of a nine month study program on mass data storage technology for rocket engine (especially the Space Shuttle Main Engine) health monitoring and control are summarized. The program had the objective of recommending a candidate mass data storage technology development for rocket engine health monitoring and control and of formulating a project plan and specification for that technology development. The work was divided into three major technical tasks: (1) development of requirements; (2) survey of mass data storage technologies; and (3) definition of a project plan and specification for technology development. The first of these tasks reviewed current data storage technology and developed a prioritized set of requirements for the health monitoring and control applications. The second task included a survey of state-of-the-art and newly developing technologies and a matrix-based ranking of the technologies. It culminated in a recommendation of optical disk technology as the best candidate for technology development. The final task defined a proof-of-concept demonstration, including tasks required to develop, test, analyze, and demonstrate the technology advancement, plus an estimate of the level of effort required. The recommended demonstration emphasizes development of an optical disk system which incorporates an order-of-magnitude increase in writing speed above the current state of the art.

  9. Effect of variety and moisture content on some engineering properties of paddy rice.

    PubMed

    Adebowale, Abdul-Rasaq A; Sanni, Lateef O; Owo, Hameed O; Karim, Olayinka R

    2011-10-01

    The effect of variety and moisture content on some engineering properties of five improved paddy rice varieties was investigated within moisture content range of 10% and 30% dry basis (d.b.). Increase in moisture content was found to increase the linear dimensions, mass of 100 seeds, surface area, apparent volume, true volume, arithmetic mean diameter, effective geometric diameter, sphericity, angle of repose, porosity and static coefficient of friction while bulk density and true density decreased with increase in moisture content. Static coefficient of friction was found to increase as moisture content increased from 0.34-0.46, 0.35-0.59, 0.36-0.46 and 0.34-0.45, respectively on plywood, galvanized steel, mild steel and glass structural surfaces. The highest static coefficient was found on galvanized steel. Angle of repose was found to increase as moisture content increases. The study concludes that variety and changes in moisture content significantly (P < 0.05) affected most of the engineering properties determined.

  10. Characterizing and engineering microtubule properties for use in hybrid nanodevices

    NASA Astrophysics Data System (ADS)

    Jeune-Smith, Yolaine

    The emergence of nanotechnology in materials science research has had a major impact in biotechnology. Nature provides novel materials and structures that can be redesigned and reassembled for engineering purposes. One system in particular is the intracellular transport system consisting of the kinesin motor protein and microtubule. For synthetic devices, either the bead geometry (kinesin motors walking along a microtubule coated surface) or the gliding geometry (microtubules gliding over a kinesin-coated surface) is used. Molecular shuttles, utilizing the gliding geometry, have the potential for use in hybrid nanodevices such as biosensors. The kinesin-powered molecular shuttle has been extensively studied. Advances have been made in controlling activation of the kinesin motors, guiding movement of kinesin motors and cargo loading onto the molecular shuttles. In this dissertation the interest in molecular shuttle development is extended with a research focus on the microtubule filament. The microtubule is a central element in the molecular shuttle. The sensing capabilities and limitations of molecular shuttles are tied to the microtubules. It would be desired to have nanodevices with molecular shuttles of predictable size, speed and lifetime. Three materials properties of the microtubules are examined. First, the microtubule length distribution is measured and compared to the length distribution of synthetic polymers. Post polymerization processing techniques, shearing and annealing, are utilized to try to reduce the polydispersity index of the microtubule length distribution. Second, the effect of kinesin activity on the lifetime of the microtubules is observed and quantified. Degradation of microtubules is monitored as a function of kinesin activity and time. Lastly, the effect of cargo loading on microtubule gliding speed is measured to gain insight on the mechanism of cargo attachment. These property behaviors will play a role in the final development of

  11. Engineering Properties of Bentonite Stabilized with Lime and Phosphogypsum

    NASA Astrophysics Data System (ADS)

    Kumar, Sujeet; Dutta, Rakesh Kumar; Mohanty, Bijayananda

    2014-12-01

    Engineering properties such as compaction, unconfined compressive strength, consistency limits, percentage swell, free swell index, the California bearing ratio and the consolidation of bentonite stabilized with lime and phosphogypsum are presented in this paper. The content of the lime and phosphogypsum varied from 0 to 10 %. The results reveal that the dry unit weight and optimum moisture content of bentonite + 8 % lime increased with the addition of 8 % phosphogypsum. The percentage of swell increased and the free swell index decreased with the addition of 8 % phosphogypsum to the bentonite + 8 % lime mix. The unconfined compressive strength of the bentonite + 8 % lime increased with the addition of 8 % phosphogypsum as well as an increase in the curing period up to 14 days. The liquid limit and plastic limit of the bentonite + 8 % lime increased, whereas the plasticity index remained constant with the addition of 8 % phosphogypsum. The California bearing ratio, modulus of subgrade reaction, and secant modulus increased for the bentonite stabilized with lime and phosphogypsum. The coefficient of the consolidation of the bentonite increased with the addition of 8 % lime and no change with the addition of 8 % phosphogypsum.

  12. Redox properties of an engineered purple Cu(A) azurin.

    PubMed

    Sun, Dapeng; Wang, Xiaotang; Davidson, Victor L

    2002-08-01

    Purple Cu(A) centers are a class of binuclear, mixed-valence copper complexes found in cytochrome c oxidase and nitrous oxide reductase. An engineered Cu(A) protein was formed by replacing a portion of the amino acid sequence that contains three of the ligands to the native type I copper center of Pseudomonas aeruginosa azurin with the corresponding portion of sequence from the Cu(A) center of cytochrome c oxidase from Paracoccus denitrificans [Proc. Natl. Acad. Sci. USA 93 (1996) 461]. Oxidation-reduction midpoint potential (E(m)) values of the Cu(A) azurin of +399+/-10 and +380+/-2mV, respectively, were determined by cyclic voltammetry and spectrochemical titration. An n value of one was obtained, indicating that the redox reaction is cycling between the mixed valence and the fully reduced states. Whereas the E(m) value of native azurin is pH dependent, the E(m) value of Cu(A) azurin is not, as expected for the Cu(A) center. Similarities and differences in the redox properties are discussed in terms of the known crystal structures of Cu(A) centers in cytochrome c oxidase and Cu(A) azurin.

  13. Engineering Property Prediction Tools for Tailored Polymer Composite Structures

    SciTech Connect

    Nguyen, Ba Nghiep; Foss, Peter; Wyzgoski, Michael; Trantina, Gerry; Kunc, Vlastimil; Schutte, Carol; Smith, Mark T.

    2009-12-23

    This report summarizes our FY 2009 research activities for the project titled:"Engineering Property Prediction Tools for Tailored Polymer Composite Structures." These activities include (i) the completion of the development of a fiber length attrition model for injection-molded long-fiber thermoplastics (LFTs), (ii) development of the a fatigue damage model for LFTs and its implementation in ABAQUS, (iii) development of an impact damage model for LFTs and its implementation in ABAQUS, (iv) development of characterization methods for fatigue testing, (v) characterization of creep and fatigue responses of glass-fiber/polyamide (PA6,6) and glass-fiber/polypropylene (PP), (vi) characterization of fiber length distribution along the flow length of glass/PA6,6 and glass-fiber/PP, and (vii) characterization of impact responses of glass-fiber/PA6,6. The fiber length attrition model accurately captures the fiber length distribution along the flow length of the studied glass-fiber/PP material. The fatigue damage model is able to predict the S-N and stiffness reduction data which are valuable to the fatigue design of LFTs. The impact damage model correctly captures damage accumulation observed in experiments of glass-fiber/PA6,6 plaques.Further work includes validations of these models for representative LFT materials and a complex LFT part.

  14. Mass-based design and optimization of wave rotors for gas turbine engine enhancement

    NASA Astrophysics Data System (ADS)

    Chan, S.; Liu, H.

    2017-03-01

    An analytic method aiming at mass properties was developed for the preliminary design and optimization of wave rotors. In the present method, we introduce the mass balance principle into the design and thus can predict and optimize the mass qualities as well as the performance of wave rotors. A dedicated least-square method with artificial weighting coefficients was developed to solve the over-constrained system in the mass-based design. This method and the adoption of the coefficients were validated by numerical simulation. Moreover, the problem of fresh air exhaustion (FAE) was put forward and analyzed, and exhaust gas recirculation (EGR) was investigated. Parameter analyses and optimization elucidated which designs would not only achieve the best performance, but also operate with minimum EGR and no FAE.

  15. Sewage sludge to landfill: some pertinent engineering properties.

    PubMed

    O'Kelly, Brendan C

    2005-06-01

    More stringent controls on the quality of wastewater discharges have given rise to increasing volumes of sewage sludge for disposal, principally to land, using either land-spreading or sludge-to-landfill operations. Current sludge-to-landfill methods generally involve mixing the concentrated sludge with other solid waste in municipal landfills. However, stricter waste disposal legislation and higher landfill taxes are forcing the water industry to look for more efficient disposal strategies. Landfill operators are also increasingly reluctant to accept sludge material in the slurry state because of construction difficulties and the potential for instability of the landfill slopes. The engineering and drying properties of a municipal sewage sludge are presented and applied, in particular, to the design, construction, and performance of sewage sludge monofills. Sludge handling and landfill construction are most effectively conducted within the water content range of 85% water content, the optimum water content for standard proctor compaction, and 95% water content, the sticky limit of the sludge material. Standard proctor compaction of the sludge within this water content range also achieves the maximum dry density of approximately 0.56 tonne/m3, which maximizes the storage capacity and, hence, the operational life of the landfill site. Undrained shear strength-water content data (pertinent to the stability of the landfill body during construction) and effective stress-strength parameters, which take into account the landfill age and the effects of ongoing sludge digestion, are presented. Landfill subsidence, which occurs principally because of creep and decomposition of the solid organic particles, is significant and continues indefinitely but at progressively slower rates.

  16. Estimation of trapped mass by in-cylinder pressure resonance in HCCI engines

    NASA Astrophysics Data System (ADS)

    Luján, José Manuel; Guardiola, Carlos; Pla, Benjamín; Bares, Pau

    2016-01-01

    High pressure gradients at homogeneous charge compression ignition (HCCI) engines heavily excite the pressure resonance. The pressure resonant frequency depends on speed of sound in the cylinder, and thus on the bulk gas temperature. Present paper profits this relation estimating the trapped mass inside the cylinder. In contrast to other estimation methods in the literature, the presented method is based on the trace of the in-cylinder pressure during the cycle; therefore, it permits a cycle-to-cycle mass estimation, and avoids errors associated with other assumptions, such as heat transfer during compression or initial temperature of the in-cylinder gases. The proposed strategy only needs the pressure signal, a volume estimation and a composition assumption to obtain several trapped mass estimates during one cycle. These estimates can be later combined for providing an error estimate of the measurement, with the assumption of negligible blow-by. The method is demonstrated in two HCCI engines of different size, showing good performance in steady operation and presenting great potential to control transient operation.

  17. Mass spectrometric analysis and aerodynamic properties of various types of combustion-related aerosol particles

    NASA Astrophysics Data System (ADS)

    Schneider, J.; Weimer, S.; Drewnick, F.; Borrmann, S.; Helas, G.; Gwaze, P.; Schmid, O.; Andreae, M. O.; Kirchner, U.

    2006-12-01

    Various types of combustion-related particles in the size range between 100 and 850 nm were analyzed with an aerosol mass spectrometer and a differential mobility analyzer. The measurements were performed with particles originating from biomass burning, diesel engine exhaust, laboratory combustion of diesel fuel and gasoline, as well as from spark soot generation. Physical and morphological parameters like fractal dimension, effective density, bulk density and dynamic shape factor were derived or at least approximated from the measurements of electrical mobility diameter and vacuum aerodynamic diameter. The relative intensities of the mass peaks in the mass spectra obtained from particles generated by a commercial diesel passenger car, by diesel combustion in a laboratory burner, and by evaporating and re-condensing lubrication oil were found to be very similar. The mass spectra from biomass burning particles show signatures identified as organic compounds like levoglucosan but also others which are yet unidentified. The aerodynamic behavior yielded a fractal dimension (Df) of 2.09 +/- 0.06 for biomass burning particles from the combustion of dry beech sticks, but showed values around three, and hence more compact particle morphologies, for particles from combustion of more natural oak. Scanning electron microscope images confirmed the finding that the beech combustion particles were fractal-like aggregates, while the oak combustion particles displayed a much more compact shape. For particles from laboratory combusted diesel fuel, a Df value of 2.35 was found, for spark soot particles, Df [approximate] 2.10. The aerodynamic properties of fractal-like particles from dry beech wood combustion indicate an aerodynamic shape factor [chi] that increases with electrical mobility diameter, and a bulk density of 1.92 g cm-3. An upper limit of [chi] [approximate] 1.2 was inferred for the shape factor of the more compact particles from oak combustion.

  18. Numerical Simulation of Mass Transfer and Three-Dimensional Fabrication of Tissue-Engineered Cartilages Based on Chitosan/Gelatin Hybrid Hydrogel Scaffold in a Rotating Bioreactor.

    PubMed

    Zhu, Yanxia; Song, Kedong; Jiang, Siyu; Chen, Jinglian; Tang, Lingzhi; Li, Siyuan; Fan, Jiangli; Wang, Yiwei; Zhao, Jiaquan; Liu, Tianqing

    2017-01-01

    Cartilage tissue engineering is believed to provide effective cartilage repair post-injuries or diseases. Biomedical materials play a key role in achieving successful culture and fabrication of cartilage. The physical properties of a chitosan/gelatin hybrid hydrogel scaffold make it an ideal cartilage biomimetic material. In this study, a chitosan/gelatin hybrid hydrogel was chosen to fabricate a tissue-engineered cartilage in vitro by inoculating human adipose-derived stem cells (ADSCs) at both dynamic and traditional static culture conditions. A bioreactor that provides a dynamic culture condition has received greater applications in tissue engineering due to its optimal mass transfer efficiency and its ability to simulate an equivalent physical environment compared to human body. In this study, prior to cell-scaffold fabrication experiment, mathematical simulations were confirmed with a mass transfer of glucose and TGF-β2 both in rotating wall vessel bioreactor (RWVB) and static culture conditions in early stage of culture via computational fluid dynamic (CFD) method. To further investigate the feasibility of the mass transfer efficiency of the bioreactor, this RWVB was adopted to fabricate three-dimensional cell-hydrogel cartilage constructs in a dynamic environment. The results showed that the mass transfer efficiency of RWVB was faster in achieving a final equilibrium compared to culture in static culture conditions. ADSCs culturing in RWVB expanded three times more compared to that in static condition over 10 days. Induced cell cultivation in a dynamic RWVB showed extensive expression of extracellular matrix, while the cell distribution was found much more uniformly distributing with full infiltration of extracellular matrix inside the porous scaffold. The increased mass transfer efficiency of glucose and TGF-β2 from RWVB promoted cellular proliferation and chondrogenic differentiation of ADSCs inside chitosan/gelatin hybrid hydrogel scaffolds. The

  19. Resonance ionization mass spectrometry and its application to trace analysis of emissions from combustion engines

    NASA Astrophysics Data System (ADS)

    Boesl, Ulrich; Nagel, Holger; Zimmermann, Ralf; Frey, Ruediger

    1997-05-01

    The principle of resonance-ionization mass spectrometry with lasers is the combination of two analytical tools, UV- spectroscopy in the gas phase and time-of-flight mass selection. The special features of this combination are: very high selectivity, high speed, multicomponent ability, and adaptability to many different problems. Examples for the latter are on-line trace analysis of emissions from combustion processes, such as from combustion engines as well as from municipal incinerators. But also monitoring of industrial procedures, e.g. food processing, are interesting applications of REMPI-MS. In this paper the principles will be shortly explained and results for the analysis of exhaust emissions from motorized vehicles presented.

  20. Mass physical properties of muddy intertidal sediments: some applications, misapplications and non-applications

    NASA Astrophysics Data System (ADS)

    Flemming, B. W.; Delafontaine, M. T.

    2000-07-01

    Mass physical properties of sediments are increasingly receiving attention outside the traditional fields of soil mechanics, geotechnical engineering and engineering geology because they are being recognised as important physical process-response parameters in sediment dynamics, benthic ecology, microbiology and biogeochemistry. In this study systematic relationships between bulk density, water content and sediment composition are presented for a variety of geographic environments. In all cases high correlations between these parameters are observed, all regions showing characteristic trends reflecting local environmental conditions. In this context, absolute water content is shown to be a universal master variable by means of which differences between individual environments can be normalised. It is postulated that relationships between water content and any other sediment parameter can be established by generating calibrations validated by carefully selected data bases which cover local ranges of sediment composition. Such site-specific calibrations can be used in regional and inter-regional modelling exercises. Thus, a universal negative relationship between absolute water content ( Wa) and dry bulk density (BD d) of common terrigenous material is expressed by the equation BD d =2.6596369 - 0.0886164 Wa+0.0088041 W1.5a - 0.0002594 W2a ( r=-0.9991, n=112). An extensive literature survey reveals that the term "concentration", which refers to a mass per unit volume, is frequently confused with the term "content" which refers to a mass per unit mass. It is demonstrated that this widespread malpractice has been responsible for serious misinterpretations of otherwise perfectly good data because quantitative comparisons are being made between parameters having different physical dimensions. In other cases, it has prevented the recognition of well-correlated relationships, resulting in incomplete arguments or unfounded speculations. In view of this, we advocate a

  1. Relationships among particle number, surface area, and respirable mass concentrations in automotive engine manufacturing.

    PubMed

    Heitbrink, William A; Evans, Douglas E; Ku, Bon Ki; Maynard, Andrew D; Slavin, Thomas J; Peters, Thomas M

    2009-01-01

    This study investigated the relationships between particle number, surface area, and respirable mass concentration measured simultaneously in a foundry and an automotive engine machining and assembly center. Aerosol concentrations were measured throughout each plant with a condensation particle counter for number concentration, a diffusion charger for active surface area concentration, and an optical particle counter for respirable mass concentration. At selected locations, particle size distributions were characterized with the optical particle counter and an electrical low pressure impactor. Statistical analyses showed that active surface area concentration was correlated with ultrafine particle number concentration and weakly correlated with respirable mass concentration. Correlation between number and active surface area concentration was stronger during winter (R2 = 0.6 for both plants) than in the summer (R2 = 0.38 and 0.36 for the foundry and engine plant respectively). The stronger correlation in winter was attributed to use of direct-fire gas fired heaters that produced substantial numbers of ultrafine particles with a modal diameter between 0.007 and 0.023 mu m. These correlations support findings obtained through theoretical analysis. Such analysis predicts that active surface area increasingly underestimates geometric surface area with increasing particle size, particularly for particles larger than 100 nm. Thus, a stronger correlation between particle number concentration and active surface area concentration is expected in the presence of high concentrations of ultrafine particles. In general, active surface area concentration may be a concentration metric that is distinct from particle number concentration and respirable mass concentration. For future health effects or toxicological studies involving nano-materials or ultrafine aerosols, this finding needs to be considered, as exposure metrics may influence data interpretation.

  2. Expendable second stage reusable space shuttle booster. Volume 4: Detail mass properties data

    NASA Technical Reports Server (NTRS)

    1971-01-01

    Mass properties data are presented to describe the characteristics of an expendable second stage with a reusable space shuttle booster. The final mass characteristics of the vehicle configurations for three specified payloads are presented in terms of weight, center of gravity, and mass moments of inertia. Three basic subjects are the integrated vehicle system, the expendable second stage, and the booster modifications.

  3. Local Government Planning Tool to Calculate Institutional and Engineering Control Costs for Brownfield Properties

    EPA Pesticide Factsheets

    This cost calculator is designed as a guide for municipal or local governments to assist in calculating their expected costs of implementing and conducting long-term stewardship of institutional controls and engineering controls at brownfield properties.

  4. Mass loss from red giants: its development, dust properties, and dependence on the stellar parameters mass, luminosity and metallicity

    NASA Astrophysics Data System (ADS)

    Wood, Peter; Blommaert, Joris; Cioni, Maria-Rosa; Feast, Michael; Groenewegen, Martin; Habing, Harm; Hony, Sacha; Loup, Cecile; Matsuura, Mikako; Omont, Alain; Waters, Rens; Whitelock, Patricia; Zijlstra, Albert; van Loon, Jacco

    2004-09-01

    We wish to obtain low resolution IRS spectra of highly evolved, low and intermediate mass stars in the Large and Small Magellanic Clouds. Our sample of stars consists of asymptotic giant branch (AGB) stars in both the general field of the Clouds and in clusters, and it complements the GTO samples of Houck and Kemper. The stars range from lower luminosity stars with small mass loss rates in the two clusters NGC419 and NGC1978 to dust-enshrouded stars in the "superwind" phase. The stars have been studied from the ground (mostly by members of this team) in order to determine spectral types, pulsation periods and amplitudes, and optical and near-infrared fluxes. Our aim is to use the IRS spectra to empirically determine the dependence of mass loss rate on stellar mass, luminosity, pulsation period and amplitude, and metallicity. We will also examine the dust properties as a function of mass loss rate, luminosity and photospheric chemical type. The AGB mass loss law resulting from this study will allow accurate AGB stellar evolution calculations to be made, meaning that reliable estimates can be made of the total mass loss from an AGB star, the stellar remnant mass, and the amounts of nucleosynthetic products ejected. Since the rate of mass return to, and enrichment of, the interstellar medium by low and intermediate mass stars depends critically on the mass loss rate and surface enrichment during the AGB phase, an accurate mass loss law will greatly enhance the reliability of galactic enrichment models. Our total request is for 31.4 hours.

  5. New engineering design, instrument modeling, and data analysis techniques for spaceborne mass spectrometers

    NASA Astrophysics Data System (ADS)

    Gershman, Daniel J.

    This work describes technological innovations that can be used to improve upon space-borne mass spectrometers (MS), enabling breakthrough science and the development of the next-generation of sensors. Emphasis is placed on the two classes of MS with the strongest spaceflight heritage: quadrupole mass spectrometers (QMS) and time-of-flight mass spectrometers (TOF-MS). For the QMS, higher order auxiliary excitation techniques are modeled and implemented for the first time for both commercial and spaceflight-like sensors. These techniques, through modest modification of instrument electronics, are shown to significantly improve upon the maximum attainable mass resolution, sensitivity, ion rejection efficiency, and stability of measured mass spectra. For the TOF-MS, a complete analysis of instrument noise sources is conducted, and a mathematical framework for instrument measurements is developed. Such a framework results in an end-to-end forward modeling of instrument noise, dataset signal-to-noise estimation, and noise event removal algorithms. The developed noise processing techniques are applied to the Fast Imaging Plasma Spectrometer (FIPS) instrument on the MErcury Surface, Space ENvironment, GEochemistry and Ranging (MESSENGER) spacecraft to enable the first ever mapping of the spatial distribution of heavy ions at Mercury, the first in situ measurements of solar wind heavy ion non-thermal properties in the inner heliosphere, as well as the first in situ measurements made inside of Earth's orbit of ionized helium originating from interstellar space.

  6. Flight and Static Exhaust Flow Properties of an F110-GE-129 Engine in an F-16XL Airplane During Acoustic Tests

    NASA Technical Reports Server (NTRS)

    Holzman, Jon K.; Webb, Lannie D.; Burcham, Frank W., Jr.

    1996-01-01

    The exhaust flow properties (mass flow, pressure, temperature, velocity, and Mach number) of the F110-GE-129 engine in an F-16XL airplane were determined from a series of flight tests flown at NASA Dryden Flight Research Center, Edwards, California. These tests were performed in conjunction with NASA Langley Research Center, Hampton, Virginia (LARC) as part of a study to investigate the acoustic characteristics of jet engines operating at high nozzle pressure conditions. The range of interest for both objectives was from Mach 0.3 to Mach 0.9. NASA Dryden flew the airplane and acquired and analyzed the engine data to determine the exhaust characteristics. NASA Langley collected the flyover acoustic measurements and correlated these results with their current predictive codes. This paper describes the airplane, tests, and methods used to determine the exhaust flow properties and presents the exhaust flow properties. No acoustics results are presented.

  7. Transient Hypoxia Improves Matrix Properties in Tissue Engineered Cartilage

    PubMed Central

    Yodmuang, Supansa; Gadjanski, Ivana; Chao, Pen-hsiu Grace; Vunjak-Novakovic, Gordana

    2014-01-01

    Adult articular cartilage is a hypoxic tissue, with oxygen tension ranging from <10% at the cartilage surface to <1% in the deepest layers. In addition to spatial gradients, cartilage development is also associated with temporal changes in oxygen tension. However, a vast majority of cartilage tissue engineering protocols involves cultivation of chondrocytes or their progenitors under ambient oxygen concentration (21% O2), that is, significantly above physiological levels in either developing or adult cartilage. Our study was designed to test the hypothesis that transient hypoxia followed by normoxic conditions results in improved quality of engineered cartilaginous ECM. To this end, we systematically compared the effects of normoxia (21% O2 for 28 days), hypoxia (5% O2 for 28 days) and transient hypoxia—reoxygenation (5% O2 for 7 days and 21% O2 for 21 days) on the matrix composition and expression of the chondrogenic genes in cartilage constructs engineered in vitro. We demonstrated that reoxygenation had the most effect on the expression of cartilaginous genes including COL2A1, ACAN, and SOX9 and increased tissue concentrations of amounts of glycosaminoglycans and type II collagen. The equilibrium Young’s moduli of tissues grown under transient hypoxia (510.01 ± 28.15 kPa) and under normoxic conditions (417.60 ± 68.46 kPa) were significantly higher than those measured under hypoxic conditions (279.61 ± 20.52 kPa). These data suggest that the cultivation protocols utilizing transient hypoxia with reoxygenation have high potential for efficient cartilage tissue engineering, but need further optimization in order to achieve higher mechanical functionality of engineered constructs. PMID:23203946

  8. Comprehensive Analysis of Coronal Mass Ejection Mass and Energy Properties Over a Full Solar Cycle

    DTIC Science & Technology

    2010-01-01

    the evolution of the solar corona and coronal mass ejections (CMEs) over a full solar cycle with high quality images and regular cadence. This is the...observed the evolution of the solar corona and coronal mass ejections (CMEs) over a full solar cycle with high quality images and regular cadence. This is...1985) and Vourlidas et al. (2002). We discuss several aspects that emerge from the statistical analysis of such a large event sample such as solar

  9. Digoxin and Adenosine Triphosphate Enhance the Functional Properties of Tissue-Engineered Cartilage

    PubMed Central

    Makris, Eleftherios A.; Huang, Brian J.; Hu, Jerry C.; Chen-Izu, Ye

    2015-01-01

    Toward developing engineered cartilage for the treatment of cartilage defects, achieving relevant functional properties before implantation remains a significant challenge. Various chemical and mechanical stimuli have been used to enhance the functional properties of engineered musculoskeletal tissues. Recently, Ca2+-modulating agents have been used to enhance matrix synthesis and biomechanical properties of engineered cartilage. The objective of this study was to determine whether other known Ca2+ modulators, digoxin and adenosine triphosphate (ATP), can be employed as novel stimuli to increase collagen synthesis and functional properties of engineered cartilage. Neocartilage constructs were formed by scaffold-free self-assembling of primary bovine articular chondrocytes. Digoxin, ATP, or both agents were added to the culture medium for 1 h/day on days 10–14. After 4 weeks of culture, neocartilage properties were assessed for gross morphology, biochemical composition, and biomechanical properties. Digoxin and ATP were found to increase neocartilage collagen content by 52–110% over untreated controls, while maintaining proteoglycan content near native tissue values. Furthermore, digoxin and ATP increased the tensile modulus by 280% and 180%, respectively, while the application of both agents increased the modulus by 380%. The trends in tensile properties were found to correlate with the amount of collagen cross-linking. Live Ca2+ imaging experiments revealed that both digoxin and ATP were able to increase Ca2+ oscillations in monolayer-cultured chondrocytes. This study provides a novel approach toward directing neocartilage maturation and enhancing its functional properties using novel Ca2+ modulators. PMID:25473799

  10. Digoxin and adenosine triphosphate enhance the functional properties of tissue-engineered cartilage.

    PubMed

    Makris, Eleftherios A; Huang, Brian J; Hu, Jerry C; Chen-Izu, Ye; Athanasiou, Kyriacos A

    2015-03-01

    Toward developing engineered cartilage for the treatment of cartilage defects, achieving relevant functional properties before implantation remains a significant challenge. Various chemical and mechanical stimuli have been used to enhance the functional properties of engineered musculoskeletal tissues. Recently, Ca(2+)-modulating agents have been used to enhance matrix synthesis and biomechanical properties of engineered cartilage. The objective of this study was to determine whether other known Ca(2+) modulators, digoxin and adenosine triphosphate (ATP), can be employed as novel stimuli to increase collagen synthesis and functional properties of engineered cartilage. Neocartilage constructs were formed by scaffold-free self-assembling of primary bovine articular chondrocytes. Digoxin, ATP, or both agents were added to the culture medium for 1 h/day on days 10-14. After 4 weeks of culture, neocartilage properties were assessed for gross morphology, biochemical composition, and biomechanical properties. Digoxin and ATP were found to increase neocartilage collagen content by 52-110% over untreated controls, while maintaining proteoglycan content near native tissue values. Furthermore, digoxin and ATP increased the tensile modulus by 280% and 180%, respectively, while the application of both agents increased the modulus by 380%. The trends in tensile properties were found to correlate with the amount of collagen cross-linking. Live Ca(2+) imaging experiments revealed that both digoxin and ATP were able to increase Ca(2+) oscillations in monolayer-cultured chondrocytes. This study provides a novel approach toward directing neocartilage maturation and enhancing its functional properties using novel Ca(2+) modulators.

  11. An engineered anisotropic nanofilm with unidirectional wetting properties

    NASA Astrophysics Data System (ADS)

    Malvadkar, Niranjan A.; Hancock, Matthew J.; Sekeroglu, Koray; Dressick, Walter J.; Demirel, Melik C.

    2010-12-01

    Anisotropic textured surfaces allow water striders to walk on water, butterflies to shed water from their wings and plants to trap insects and pollen. Capturing these natural features in biomimetic surfaces is an active area of research. Here, we report an engineered nanofilm, composed of an array of poly(p-xylylene) nanorods, which demonstrates anisotropic wetting behaviour by means of a pin-release droplet ratchet mechanism. Droplet retention forces in the pin and release directions differ by up to 80μN, which is over ten times greater than the values reported for other engineered anisotropic surfaces. The nanofilm provides a microscale smooth surface on which to transport microlitre droplets, and is also relatively easy to synthesize by a bottom-up vapour-phase technique. An accompanying comprehensive model successfully describes the film's anisotropic wetting behaviour as a function of measurable film morphology parameters.

  12. Historic Properties Report: Stratford Army Engine Plant, Connecticut.

    DTIC Science & Technology

    1984-07-01

    Abrams XMl Main Battle Tank. In May 1979 Stratford Division contracted for the first 110 XMI production engines. 2 8 Avco Lycoming also introduced the...helicopter accomplishments see his autobiography The Study of Winged-S; Moran, Aeroplanes Vought, p. 71; Norman Polmar and Floyd D. Kennedy, Jr., Military... Floyd D. Jr. Military Helicopters of the World. Annapolis, Maryland: Naval Institute Press, 1981. Concise guide to historic and contemporary helicopters

  13. Micro-CT-based screening of biomechanical and structural properties of bone tissue engineering scaffolds.

    PubMed

    Van Cleynenbreugel, Tim; Schrooten, Jan; Van Oosterwyck, Hans; Vander Sloten, Jos

    2006-07-01

    The development of successful scaffolds for bone tissue engineering requires a concurrent engineering approach that combines different research fields. In order to limit in vivo experiments and reduce trial and error research, a scaffold screening technique has been developed. In this protocol seven structural and three biomechanical properties of potential scaffold materials are quantified and compared to the desired values. The property assessment is done on computer models of the scaffolds, and these models are based on micro-CT images. As a proof of principle, three porous scaffolds were evaluated with this protocol: stainless steel, hydroxyapatite, and titanium. These examples demonstrate that the modelling technique is able to quantify important scaffold properties. Thus, a powerful technique for automated screening of bone tissue engineering scaffolds has been developed that in a later stage may be used to tailor the scaffold properties to specific requirements.

  14. Education of Intellectual Properties for the Training of Creative Engineers

    NASA Astrophysics Data System (ADS)

    Ito, Yoshifumi; Kajiwara, Katuhiko; Oodan, Kyouji

    Kurume National College of Technology has obtained results concerning intellectual property education combined with inventive education. In the education program, students learn about industrial property and practical expertise such as searching the open patents, making up patent-maps, and making patent application papers to the Patent Office under the guidance of a teacher, a patent adviser and attorney. As a result, some of the creative students have already applied for patents. In the future, we are going to prepare a managing system for the intellectual property at our college for the intensification of cooperative application with the local company.

  15. Prediction of Mass Evaporation of During Measurements of Thermophysical Properties Using an Electrostatic Levitator

    NASA Astrophysics Data System (ADS)

    Lee, J.; Matson, D. M.

    2014-10-01

    This paper describes the prediction of mass evaporation of at% alloys during thermophysical property measurements using the electrostatic levitator at NASA Marshall Space Flight Center in Huntsville, AL. The final mass, final composition, and activity of individual component are considered in the calculation of mass evaporation. The predicted reduction in mass and variation in composition are validated with six ESL samples which underwent different thermal cycles. The predicted mass evaporation and composition shift show good agreement with experiments with the maximum relative errors of 4.8 % and 1.7 %, respectively.

  16. Determination of densified biomass mass properties using 3D laser scanning and image analysis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biomass densification is viewed as the indispensable feedstock preprocessing operation for efficient transport, storage, material flow through machines, and handling activities. Accurate mass properties of densified biomass such as surface area, volume, and envelope density form fundamental data for...

  17. Engineering cell-compatible paper chips for cell culturing, drug screening, and mass spectrometric sensing.

    PubMed

    Chen, Qiushui; He, Ziyi; Liu, Wu; Lin, Xuexia; Wu, Jing; Li, Haifang; Lin, Jin-Ming

    2015-10-28

    Paper-supported cell culture is an unprecedented development for advanced bioassays. This study reports a strategy for in vitro engineering of cell-compatible paper chips that allow for adherent cell culture, quantitative assessment of drug efficiency, and label-free sensing of intracellular molecules via paper spray mass spectrometry. The polycarbonate paper is employed as an excellent alternative bioscaffold for cell distribution, adhesion, and growth, as well as allowing for fluorescence imaging without light scattering. The cell-cultured paper chips are thus amenable to fabricate 3D tissue construction and cocultures by flexible deformation, stacks and assembly by layers of cells. As a result, the successful development of cell-compatible paper chips subsequently offers a uniquely flexible approach for in situ sensing of live cell components by paper spray mass spectrometry, allowing profiling the cellular lipids and quantitative measurement of drug metabolism with minimum sample pretreatment. Consequently, the developed paper chips for adherent cell culture are inexpensive for one-time use, compatible with high throughputs, and amenable to label-free and rapid analysis.

  18. Physical properties, chemical composition, and cloud forming potential of particulate emissions from a marine diesel engine at various load conditions.

    PubMed

    Petzold, A; Weingartner, E; Hasselbach, J; Lauer, P; Kurok, C; Fleischer, F

    2010-05-15

    Particulate matter (PM) emissions from one serial 4-stroke medium-speed marine diesel engine were measured for load conditions from 10% to 110% in test rig studies using heavy fuel oil (HFO). Testing the engine across its entire load range permitted the scaling of exhaust PM properties with load. Emission factors for particle number, particle mass, and chemical compounds were determined. The potential of particles to form cloud droplets (cloud condensation nuclei, CCN) was calculated from chemical composition and particle size. Number emission factors are (3.43 +/- 1.26) x 10(16) (kg fuel)(-1) at 85-110% load and (1.06 +/- 0.10) x 10(16) (kg fuel)(-1) at 10% load. CCN emission factors of 1-6 x 10(14) (kg fuel)(-1) are at the lower bound of data reported in the literature. From combined thermal and optical methods, black carbon (BC) emission factors of 40-60 mg/(kg fuel) were determined for 85-100% load and 370 mg/(kg fuel) for 10% load. The engine load dependence of the conversion efficiency for fuel sulfur into sulfate of (1.08 +/- 0.15)% at engine idle to (3.85 +/- 0.41)% at cruise may serve as input to global emission calculations for various load conditions.

  19. Method for simultaneous measurement of mass loading and fluid property changes using a quartz crystal microbalance

    DOEpatents

    Granstaff, Victoria E.; Martin, Stephen J.

    1993-01-01

    A method, using a quartz crystal microbalance, to obtain simultaneous measurement of solid mass accumulation and changes in liquid density-viscosity product. The simultaneous real-time measurements of electrical parameters yields that changes in surface mass can be differentiated from changes in solution properties. Two methods to obtain the admittance/frequency data are employed.

  20. Method for simultaneous measurement of mass loading and fluid property changes using a quartz crystal microbalance

    DOEpatents

    Granstaff, V.E.; Martin, S.J.

    1993-04-13

    A method is described, using a quartz crystal microbalance, to obtain simultaneous measurement of solid mass accumulation and changes in liquid density-viscosity product. The simultaneous real-time measurements of electrical parameters yields that changes in surface mass can be differentiated from changes in solution properties. Two methods to obtain the admittance/frequency data are employed.

  1. Unexpected property of ectoine synthase and its application for synthesis of the engineered compatible solute ADPC.

    PubMed

    Witt, Elisabeth M H J; Davies, Noel W; Galinski, Erwin A

    2011-07-01

    A new cyclic amino acid was detected in a deletion mutant of the moderately halophilic bacterium Halomonas elongata deficient in ectoine synthesis. Using mass spectroscopy (MS) and nuclear magnetic resonance (NMR) techniques, the substance was identified as 5-amino-3,4-dihydro-2H-pyrrole-2-carboxylate (ADPC). We were able to demonstrate that ADPC is the product of a side reaction of lone ectoine synthase (EC 4.2.1.108), which forms ADPC by cyclic condensation of glutamine. This reaction was shown to be reversible. Subsequently, a number of ectoine derivatives, in particular 4,5-dihydro-2-methylimidazole-4-carboxylate (DHMICA) and homoectoine, were also shown to be cleaved by ectoine synthase, which is classified as a hydro-lyase. This study thus reports for the first time that ectoine synthase accepts more than one substrate and is a reversible enzyme able to catalyze both the intramolecular condensation into and the hydrolytic cleavage of cyclic amino acid derivatives. As ADPC supports growth of bacteria under salt stress conditions and stabilizes enzymes against freeze-thaw denaturation, it displays typical properties of compatible solutes. As ADPC has not yet been described as a natural compound, it is presented here as the first man-made compatible solute created through genetic engineering.

  2. Band structure engineering and thermoelectric properties of charge-compensated filled skutterudites

    DOE PAGES

    Shi, Xiaoya; Yang, Jiong; Wu, Lijun; ...

    2015-10-12

    Thermoelectric properties of semiconductors are intimately related to their electronic band structure, which can be engineered via chemical doping. Dopant Ga in the cage-structured skutterudite Co4Sb12 substitutes Sb sites while occupying the void sites. Combining quantitative scanning transmission electron microscopy and first-principles calculations, we show that Ga dual-site occupancy breaks the symmetry of the Sb-Sb network, splits the deep triply-degenerate conduction bands, and drives them downward to the band edge. The charge-compensating nature of the dual occupancy Ga increases overall filling fraction limit. By imparting this unique band structure feature, and judiciously doping the materials by increasing the Yb content,more » we promote the Fermi level to a point where carriers are in energetic proximity to these features. Increased participation of these heavier bands in electronic transport leads to increased thermopower and effective mass. Further, the localized distortion from Ga/Sb substitution enhances the phonon scattering to reduce the thermal conductivity effectively.« less

  3. Band structure engineering and thermoelectric properties of charge-compensated filled skutterudites

    SciTech Connect

    Shi, Xiaoya; Yang, Jiong; Wu, Lijun; Salvador, James R.; Zhang, Cheng; Villaire, William L.; Haddad, Daad; Yang, Jihui; Zhu, Yimei; Li, Qiang

    2015-10-12

    Thermoelectric properties of semiconductors are intimately related to their electronic band structure, which can be engineered via chemical doping. Dopant Ga in the cage-structured skutterudite Co4Sb12 substitutes Sb sites while occupying the void sites. Combining quantitative scanning transmission electron microscopy and first-principles calculations, we show that Ga dual-site occupancy breaks the symmetry of the Sb-Sb network, splits the deep triply-degenerate conduction bands, and drives them downward to the band edge. The charge-compensating nature of the dual occupancy Ga increases overall filling fraction limit. By imparting this unique band structure feature, and judiciously doping the materials by increasing the Yb content, we promote the Fermi level to a point where carriers are in energetic proximity to these features. Increased participation of these heavier bands in electronic transport leads to increased thermopower and effective mass. Further, the localized distortion from Ga/Sb substitution enhances the phonon scattering to reduce the thermal conductivity effectively.

  4. Multi-component nanofibrous scaffolds with tunable properties for bone tissue engineering

    NASA Astrophysics Data System (ADS)

    Jose, Moncy V.

    Bone is a highly complex tissue which is an integral part of vertebrates and hence any damage has a major negative effect on the quality of life. Tissue engineering is regarded as an ideal route to resolve the issues related to the scarcity of tissue and organ for transplantation. Apart from cell line and growth factors, the choice of materials and fabrication technique for scaffold are equally important. The goal of this work was to develop a multi-component nanofibrous scaffold based on a synthetic polymer (poly(lactic-co-glycolide) (PLGA)), a biopolymer (collagen) and a biomineral (nano-hydroxyapatite (nano-HA)) by electrospinning technique, which mimics the nanoscopic, chemical, and anisotropic features of bone. Preliminary studies involved fabrication of nanocomposite scaffolds based on PLGA and nano-HA. Morphological and mechanical characterizations revealed that at low concentrations, nano-HA acted as reinforcements, whereas at higher concentrations the presence of aggregation was detrimental to the scaffold. Hydrolytic degradation studies revealed the scaffold had a little mass loss and the mechanical property was maintained for a period of 6 weeks. This study was followed by evaluation of a blend system based on PLGA and collagen. Collagen addition provides hydrophilicity and the necessary cell binding sites in PLGA. The structural characterization revealed that the blend had limited interactions between the two components. The mechanical characterization revealed that with increasing collagen concentration, there was a decline in mechanical properties. However, crosslinking of the blend system, with carbodiimide (EDC) resulted in improving the mechanical properties of the scaffolds. A multi-component system was developed by adding different concentrations of nano-HA to a fixed PLGA/collagen blend composition (80/20). Morphological and mechanical characterizations revealed properties similar to the PLGA/HA system. Cyto-compatibility studies revealed

  5. Bioinspired Reductionistic Peptide Engineering for Exceptional Mechanical Properties.

    PubMed

    Avinash, M B; Raut, Devaraj; Mishra, Manish Kumar; Ramamurty, Upadrasta; Govindaraju, T

    2015-11-03

    A simple solution-processing and self-assembly approach that exploits the synergistic interactions between multiple hydrogen bonded networks and aromatic interactions was utilized to synthesize molecular crystals of cyclic dipeptides (CDPs), whose molecular weights (~0.2 kDa) are nearly three orders of magnitude smaller than that of natural structural proteins (50-300 kDa). Mechanical properties of these materials, measured using the nanoindentation technique, indicate that the stiffness and strength are comparable and sometimes better than those of natural fibres. The measured mechanical responses were rationalized by recourse to the crystallographic structural analysis and intermolecular interactions in the self-assembled single crystals. With this work we highlight the significance of developing small molecule based bioinspired design strategies to emulate biomechanical properties. A particular advantage of the successfully demonstrated reductionistic strategy of the present work is its amenability for realistic industrial scale manufacturing of designer biomaterials with desired mechanical properties.

  6. Bioinspired Reductionistic Peptide Engineering for Exceptional Mechanical Properties

    PubMed Central

    Avinash, M. B.; Raut, Devaraj; Mishra, Manish Kumar; Ramamurty, Upadrasta; Govindaraju, T.

    2015-01-01

    A simple solution-processing and self-assembly approach that exploits the synergistic interactions between multiple hydrogen bonded networks and aromatic interactions was utilized to synthesize molecular crystals of cyclic dipeptides (CDPs), whose molecular weights (~0.2 kDa) are nearly three orders of magnitude smaller than that of natural structural proteins (50–300 kDa). Mechanical properties of these materials, measured using the nanoindentation technique, indicate that the stiffness and strength are comparable and sometimes better than those of natural fibres. The measured mechanical responses were rationalized by recourse to the crystallographic structural analysis and intermolecular interactions in the self-assembled single crystals. With this work we highlight the significance of developing small molecule based bioinspired design strategies to emulate biomechanical properties. A particular advantage of the successfully demonstrated reductionistic strategy of the present work is its amenability for realistic industrial scale manufacturing of designer biomaterials with desired mechanical properties. PMID:26525957

  7. Bioinspired Reductionistic Peptide Engineering for Exceptional Mechanical Properties

    NASA Astrophysics Data System (ADS)

    Avinash, M. B.; Raut, Devaraj; Mishra, Manish Kumar; Ramamurty, Upadrasta; Govindaraju, T.

    2015-11-01

    A simple solution-processing and self-assembly approach that exploits the synergistic interactions between multiple hydrogen bonded networks and aromatic interactions was utilized to synthesize molecular crystals of cyclic dipeptides (CDPs), whose molecular weights (~0.2 kDa) are nearly three orders of magnitude smaller than that of natural structural proteins (50-300 kDa). Mechanical properties of these materials, measured using the nanoindentation technique, indicate that the stiffness and strength are comparable and sometimes better than those of natural fibres. The measured mechanical responses were rationalized by recourse to the crystallographic structural analysis and intermolecular interactions in the self-assembled single crystals. With this work we highlight the significance of developing small molecule based bioinspired design strategies to emulate biomechanical properties. A particular advantage of the successfully demonstrated reductionistic strategy of the present work is its amenability for realistic industrial scale manufacturing of designer biomaterials with desired mechanical properties.

  8. Physical and Biological Properties of Engineered Protein Hydrogels

    NASA Astrophysics Data System (ADS)

    Tirrell, David

    2012-02-01

    Injectable hydrogels show substantial promise for use in minimally invasive tissue engineering and drug delivery procedures. A new injectable hydrogel material, developed from recombinant telechelic proteins expressed in E. coli, demonstrates shear thinning by three orders of magnitude at large strains. Large amplitude oscillatory shear illustrates that shear thinning is due to yielding within the bulk of the gel, and the rheological response and flow profiles are consistent with a shear-banding mechanism for yielding. The sharp yielding transition and large magnitude of the apparent shear thinning allow gels to be injected through narrow gauge needles with only gentle hand pressure. After injection the gels reset to full elastic strength in seconds due to rapid reformation of the physical network junctions, allowing self-supporting structures to be formed. The shear thinning behavior is largely independent of the midblock length, enabling genetic engineering to be used to control the equilibrium modulus of the gel without loss of the characteristic yielding behavior. The shear-banding mechanism localizes shear stresses during flow into narrow regions of the gel, allowing more than 95% of seeded cells to survive the injection process.

  9. Chemical analysis of diesel engine nanoparticles using a nano-DMA/thermal desorption particle beam mass spectrometer.

    PubMed

    Tobias, H J; Beving, D E; Ziemann, P J; Sakurai, H; Zuk, M; McMurry, P H; Zarling, D; Waytulonis, R; Kittelson, D B

    2001-06-01

    Diesel engines are known to emit high number concentrations of nanoparticles (diameter < 50 nm), but the physical and chemical mechanisms by which they form are not understood. Information on chemical composition is lacking because the small size, low mass concentration, and potential for contamination of samples obtained by standard techniques make nanoparticles difficult to analyze. A nano-differential mobility analyzer was used to size-select nanoparticles (mass median diameter approximately 25-60 nm) from diesel engine exhaust for subsequent chemical analysis by thermal desorption particle beam mass spectrometry. Mass spectra were used to identify and quantify nanoparticle components, and compound molecular weights and vapor pressures were estimated from calibrated desorption temperatures. Branched alkanes and alkyl-substituted cycloalkanes from unburned fuel and/or lubricating oil appear to contribute most of the diesel nanoparticle mass. The volatility of the organic fraction of the aerosol increases as the engine load decreases and as particle size increases. Sulfuric acid was also detected at estimated concentrations of a few percent of the total nanoparticle mass. The results are consistent with a mechanism of nanoparticle formation involving nucleation of sulfuric acid and water, followed by particle growth by condensation of organic species.

  10. Genetic engineering, high resolution mass spectrometry and nuclear magnetic resonance spectroscopy elucidate the bikaverin biosynthetic pathway in Fusarium fujikuroi.

    PubMed

    Arndt, Birgit; Studt, Lena; Wiemann, Philipp; Osmanov, Helena; Kleigrewe, Karin; Köhler, Jens; Krug, Isabel; Tudzynski, Bettina; Humpf, Hans-Ulrich

    2015-11-01

    Secondary metabolites of filamentous fungi can be highly bioactive, ranging from antibiotic to cancerogenic properties. In this study we were able to identify a new, yet unknown metabolite produced by Fusarium fujikuroi, an ascomycetous rice pathogen. With the help of genomic engineering and high-performance liquid chromatography (HPLC) coupled to high resolution mass spectrometry (HRMS) followed by isolation and detailed structure elucidation, the new substance could be designated as an unknown bikaverin precursor, missing two methyl- and one hydroxy group, hence named oxo-pre-bikaverin. Though the bikaverin gene cluster has been extensively studied in the past, elucidation of the biosynthetic pathway remained elusive due to a negative feedback loop that regulates the genes within the cluster. To decipher the bikaverin biosynthetic pathway and to overcome these negative regulation circuits, the structural cluster genes BIK2 and BIK3 were overexpressed independently in the ΔΔBIK2/BIK3+OE::BIK1 mutant background by using strong constitutive promoters. Using the software tool MZmine 2, the metabolite profile of the generated mutants obtained by HPLC-HRMS was compared, revealing further intermediates.

  11. Engineering Biomaterial Properties for Central Nervous System Applications

    NASA Astrophysics Data System (ADS)

    Rivet, Christopher John

    Biomaterials offer unique properties that are intrinsic to the chemistry of the material itself or occur as a result of the fabrication process; iron oxide nanoparticles are superparamagnetic, which enables controlled heating in the presence of an alternating magnetic field, and a hydrogel and electrospun fiber hybrid material provides minimally invasive placement of a fibrous, artificial extracellular matrix for tissue regeneration. Utilization of these unique properties towards central nervous system disease and dysfunction requires a thorough definition of the properties in concert with full biological assessment. This enables development of material-specific features to elicit unique cellular responses. Iron oxide nanoparticles are first investigated for material-dependent, cortical neuron cytotoxicity in vitro and subsequently evaluated for alternating magnetic field stimulation induced hyperthermia, emulating the clinical application for enhanced chemotherapy efficacy in glioblastoma treatment. A hydrogel and electrospun fiber hybrid material is first applied to a rat brain to evaluate biomaterial interface astrocyte accumulation as a function of hybrid material composition. The hybrid material is then utilized towards increasing functional engraftment of dopaminergic progenitor neural stem cells in a mouse model of Parkinson's disease. Taken together, these two scenarios display the role of material property characterization in development of biomaterial strategies for central nervous system repair and regeneration.

  12. Bringing Outreach into the Engineering Classroom--A Mass and Heat Transfer Course Project

    ERIC Educational Resources Information Center

    Eniola-Adefeso, Omolola

    2010-01-01

    One major contributing factor to the low number of students receiving degrees in engineering is the two decades of steady decline in student enrollment in engineering disciplines. Evidence in the literature suggests that this decline can be linked to K-12 students' lack of knowledge of engineering careers and their perception of engineering as…

  13. Quantitative Ultrasonic Evaluation of Mechanical Properties of Engineering Materials

    NASA Technical Reports Server (NTRS)

    Vary, A.

    1978-01-01

    Progress in the application of ultrasonic techniques to nondestructive measurement of mechanical strength of engineering materials is reviewed. A dormant concept in nondestructive evaluation (NDE) is invoked. The availability of ultrasonic methods that can be applied to actual parts to assess their potential susceptibility to failure under design conditions is discussed. It was shown that ultrasonic methods yield measurements of elastic moduli, microstructure, hardness, fracture toughness, tensile strength, yield strength, and shear strength for a wide range of materials (including many types of metals, ceramics, and fiber composites). It was also indicated that although most of these methods were shown feasible in laboratory studies, more work is needed before they can be used on actual parts in processing, assembly, inspection, and maintenance lines.

  14. Rational engineering of physicochemical properties of nanomaterials for biomedical applications with nanotoxicological perspectives

    NASA Astrophysics Data System (ADS)

    Navya, P. N.; Daima, Hemant Kumar

    2016-02-01

    Innovative engineered nanomaterials are at the leading edge of rapidly emerging fields of nanobiotechnology and nanomedicine. Meticulous synthesis, unique physicochemical properties, manifestation of chemical or biological moieties on the surface of materials make engineered nanostructures suitable for a variety of biomedical applications. Besides, tailored nanomaterials exhibit entirely novel therapeutic applications with better functionality, sensitivity, efficiency and specificity due to their customized unique physicochemical and surface properties. Additionally, such designer made nanomaterials has potential to generate series of interactions with various biological entities including DNA, proteins, membranes, cells and organelles at nano-bio interface. These nano-bio interactions are driven by colloidal forces and predominantly depend on the dynamic physicochemical and surface properties of nanomaterials. Nevertheless, recent development and atomic scale tailoring of various physical, chemical and surface properties of nanomaterials is promising to dictate their interaction in anticipated manner with biological entities for biomedical applications. As a result, rationally designed nanomaterials are in extensive demand for bio-molecular detection and diagnostics, therapeutics, drug and gene delivery, fluorescent labelling, tissue engineering, biochemical sensing and other pharmaceuticals applications. However, toxicity and risk associated with engineered nanomaterials is rather unclear or not well understood; which is gaining considerable attention and the field of nanotoxicology is evolving promptly. Therefore, this review explores current knowledge of articulate engineering of nanomaterials for biomedical applications with special attention on potential toxicological perspectives.

  15. Rational engineering of physicochemical properties of nanomaterials for biomedical applications with nanotoxicological perspectives.

    PubMed

    Navya, P N; Daima, Hemant Kumar

    2016-01-01

    Innovative engineered nanomaterials are at the leading edge of rapidly emerging fields of nanobiotechnology and nanomedicine. Meticulous synthesis, unique physicochemical properties, manifestation of chemical or biological moieties on the surface of materials make engineered nanostructures suitable for a variety of biomedical applications. Besides, tailored nanomaterials exhibit entirely novel therapeutic applications with better functionality, sensitivity, efficiency and specificity due to their customized unique physicochemical and surface properties. Additionally, such designer made nanomaterials has potential to generate series of interactions with various biological entities including DNA, proteins, membranes, cells and organelles at nano-bio interface. These nano-bio interactions are driven by colloidal forces and predominantly depend on the dynamic physicochemical and surface properties of nanomaterials. Nevertheless, recent development and atomic scale tailoring of various physical, chemical and surface properties of nanomaterials is promising to dictate their interaction in anticipated manner with biological entities for biomedical applications. As a result, rationally designed nanomaterials are in extensive demand for bio-molecular detection and diagnostics, therapeutics, drug and gene delivery, fluorescent labelling, tissue engineering, biochemical sensing and other pharmaceuticals applications. However, toxicity and risk associated with engineered nanomaterials is rather unclear or not well understood; which is gaining considerable attention and the field of nanotoxicology is evolving promptly. Therefore, this review explores current knowledge of articulate engineering of nanomaterials for biomedical applications with special attention on potential toxicological perspectives.

  16. Project Palanquin. Preshot Geologic and Engineering Properties Investigations

    DTIC Science & Technology

    1968-10-11

    formation. The uppermost flow of this formation is porphyritic trachyte , which is at least 351 feet thick beneath the site. The Ribbon Cliff formation is... trachyte is severely altered and decomposed within zones of intense fractur- ing related to faulting. Subsurface data indicate the presence of a high-angle...property values of the porphyritic trachyte are as follows: dry bulk specific gravity, 2.49; dry bulk density, 155 pcf; static unconfined compressive

  17. A thermodynamic approach to obtain materials properties for engineering applications

    NASA Technical Reports Server (NTRS)

    Chang, Y. Austin

    1993-01-01

    With the ever increases in the capabilities of computers for numerical computations, we are on the verge of using these tools to model manufacturing processes for improving the efficiency of these processes as well as the quality of the products. One such process is casting for the production of metals. However, in order to model metal casting processes in a meaningful way it is essential to have the basic properties of these materials in their molten state, solid state as well as in the mixed state of solid and liquid. Some of the properties needed may be considered as intrinsic such as the density, heat capacity or enthalpy of freezing of a pure metal, while others are not. For instance, the enthalpy of solidification of an alloy is not a defined thermodynamic quantity. Its value depends on the micro-segregation of the phases during the course of solidification. The objective of the present study is to present a thermodynamic approach to obtain some of the intrinsic properties and combining thermodynamics with kinetic models to estimate such quantities as the enthalpy of solidification of an alloy.

  18. Venus cloud properties: Infrared opacity and mass mixing ratio

    NASA Technical Reports Server (NTRS)

    Samuelson, R. E.; Hanel, R. A.; Herath, L. W.; Kunde, V. G.; Maguire, W. C.

    1974-01-01

    By using the Mariner 5 temperature profile and a homogeneous cloud model, and assuming that CO2 and cloud particles are the only opacity sources, the wavelength dependence of the Venus cloud opacity is inferred from the infrared spectrum of the planet between 450 and 1250/cm. Justification for applying the homogeneous cloud model is found in the fact that numerous polarization and infrared data are mutually consistent within the framework of such a model; on the other hand, dense cloud models are not satisfactory. Volume extinction coefficients varying from 0.000005 to 0.000015/cm depending on the wavelength, are determined at the tropopause level of 6110 km. By using all available data, a cloud mass mixing ratio of approximately 0.000005 and a particle concentration of about 900 particles per cu cm at this level are also inferred. The derived cloud opacity compares favorably with that expected for a haze of droplets of a 75% aqueous solution of sulfuric acid.

  19. Galaxy and Mass Assembly (GAMA): merging galaxies and their properties

    NASA Astrophysics Data System (ADS)

    De Propris, Roberto; Baldry, Ivan K.; Bland-Hawthorn, Joss; Brough, Sarah; Driver, Simon P.; Hopkins, Andrew M.; Kelvin, Lee; Loveday, Jon; Phillipps, Steve; Robotham, Aaron S. G.

    2014-11-01

    We derive the close pair fractions and volume merger rates for galaxies in the Galaxy and Mass Assembly (GAMA) survey with -23 < Mr < -17 (ΩM = 0.27, ΩΛ = 0.73, H0 = 100 km s-1 Mpc-1) at 0.01 < z < 0.22 (look-back time of <2 Gyr). The merger fraction is approximately 1.5 per cent Gyr-1 at all luminosities (assuming 50 per cent of pairs merge) and the volume merger rate is ≈3.5 × 10-4 Mpc-3 Gyr-1. We examine how the merger rate varies by luminosity and morphology. Dry mergers (between red/spheroidal galaxies) are found to be uncommon and to decrease with decreasing luminosity. Fainter mergers are wet, between blue/discy galaxies. Damp mergers (one of each type) follow the average of dry and wet mergers. In the brighter luminosity bin (-23 < Mr < -20), the merger rate evolution is flat, irrespective of colour or morphology, out to z ˜ 0.2. The makeup of the merging population does not appear to change over this redshift range. Galaxy growth by major mergers appears comparatively unimportant and dry mergers are unlikely to be significant in the buildup of the red sequence over the past 2 Gyr. We compare the colour, morphology, environmental density and degree of activity (BPT class, Baldwin, Phillips & Terlevich) of galaxies in pairs to those of more isolated objects in the same volume. Galaxies in close pairs tend to be both redder and slightly more spheroid dominated than the comparison sample. We suggest that this may be due to `harassment' in multiple previous passes prior to the current close interaction. Galaxy pairs do not appear to prefer significantly denser environments. There is no evidence of an enhancement in the AGN fraction in pairs, compared to other galaxies in the same volume.

  20. Engineering Database of Liquid Salt Thermophysical and Thermochemical Properties

    SciTech Connect

    Manohar S. Sohal; Matthias A. Ebner; Piyush Sabharwall; Phil Sharpe

    2010-03-01

    The purpose of this report is to provide a review of thermodynamic and thermophysical properties of candidate molten salt coolants, which may be used as a primary coolant within a nuclear reactor or heat transport medium from the Next Generation Nuclear Plant (NGNP) to a processing plant, for example, a hydrogen-production plant. Thermodynamic properties of four types of molten salts, including LiF-BeF2 (67 and 33 mol%, respectively; also known as FLiBe), LiF-NaF-KF (46.5, 11.5, and 52 mol%, also known as FLiNaK), and KCl-MgCl2 (67 and 33 mol%), and sodium nitrate-sodium nitrite-potassium nitrate (NaNO3–NaNO2–KNO3, (7-49-44 or 7-40-53 mol%) have been investigated. Limitations of existing correlations to predict density, viscosity, specific heat capacity, surface tension, and thermal conductivity, were identified. The impact of thermodynamic properties on the heat transfer, especially Nusselt number was also discussed. Stability of the molten salts with structural alloys and their compatibility with the structural alloys was studied. Nickel and alloys with dense Ni coatings are effectively inert to corrosion in fluorides but not so in chlorides. Of the chromium containing alloys, Hastelloy N appears to have the best corrosion resistance in fluorides, while Haynes 230 was most resistant in chloride. In general, alloys with increasing carbon and chromium content are increasingly subject to corrosion by the fluoride salts FLiBe and FLiNaK, due to attack and dissolution of the intergranular chromium carbide. Future research to obtain needed information was identified.

  1. Molecular outflows driven by low-mass protostars. I. Correcting for underestimates when measuring outflow masses and dynamical properties

    SciTech Connect

    Dunham, Michael M.; Arce, Héctor G.; Mardones, Diego; Lee, Jeong-Eun; Matthews, Brenda C.; Stutz, Amelia M.; Williams, Jonathan P.

    2014-03-01

    We present a survey of 28 molecular outflows driven by low-mass protostars, all of which are sufficiently isolated spatially and/or kinematically to fully separate into individual outflows. Using a combination of new and archival data from several single-dish telescopes, 17 outflows are mapped in {sup 12}CO (2-1) and 17 are mapped in {sup 12}CO (3-2), with 6 mapped in both transitions. For each outflow, we calculate and tabulate the mass (M {sub flow}), momentum (P {sub flow}), kinetic energy (E {sub flow}), mechanical luminosity (L {sub flow}), and force (F {sub flow}) assuming optically thin emission in LTE at an excitation temperature, T {sub ex}, of 50 K. We show that all of the calculated properties are underestimated when calculated under these assumptions. Taken together, the effects of opacity, outflow emission at low velocities confused with ambient cloud emission, and emission below the sensitivities of the observations increase outflow masses and dynamical properties by an order of magnitude, on average, and factors of 50-90 in the most extreme cases. Different (and non-uniform) excitation temperatures, inclination effects, and dissociation of molecular gas will all work to further increase outflow properties. Molecular outflows are thus almost certainly more massive and energetic than commonly reported. Additionally, outflow properties are lower, on average, by almost an order of magnitude when calculated from the {sup 12}CO (3-2) maps compared to the {sup 12}CO (2-1) maps, even after accounting for different opacities, map sensitivities, and possible excitation temperature variations. It has recently been argued in the literature that the {sup 12}CO (3-2) line is subthermally excited in outflows, and our results support this finding.

  2. Preparation of gelatin based porous biocomposite for bone tissue engineering and evaluation of gamma irradiation effect on its properties.

    PubMed

    Islam, Md Minhajul; Khan, Mubarak A; Rahman, Mohammed Mizanur

    2015-04-01

    Biodegradable porous hybrid polymer composites were prepared by using gelatin as base polymer matrix, β-tricalcium phosphate (TCP) and calcium sulfate (CS) as cementing materials, chitosan as an antimicrobial agent, and glutaraldehyde and polyethylene glycol (PEG) as crosslinkers at different mass ratios. Thereafter, the composites were subjected to γ-radiation sterilization. The structure and properties of these composite scaffolds were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), mechanical properties testing (compressive, bending, tensile and impact), thermogravimetry/differential thermal analysis (TG/DTA), and physical stability test in simulated body fluid (SBF). We found that TCP rich composites showed enhanced mechanical properties among all the crosslinked composites. γ-Radiation sterilization triggered further cross linking in polymer matrix resulting a decrease in pore size of the composites and an increase in pore wall thickness with improved mechanical and thermal properties. The chemically crosslinked composite with 40% TCP followed by γ-radiation sterilization showed the smallest pore size distribution with a mean pore diameter of 159.22μm, which falls in the range of 100-350μm - known to be suitable for osteoconduction. Considering its improved mechanical and thermal properties along with osteoconduction ability without cytotoxicity, we propose this biocomposite as a viable candidate for bone tissue engineering.

  3. Band gap engineering and optical properties of tungsten trioxide

    NASA Astrophysics Data System (ADS)

    Ping, Yuan; Li, Yan; Rocca, Dario; Gygi, Francois; Galli, Giulia

    2012-02-01

    Tungsten trioxide (WO3) is a good photoanode material for water oxidation but it is not an efficient absorber of sunlight because of its large band gap (2.6 eV). Recently, stable clathrates of WO3 with interstitial N2 molecules were synthesized [1], which are isostructural to monoclinic WO3 but have a substantially smaller bang gap, 1.8 eV. We have studied the structural, electronic, an vibrational properties of N2-WO3 clathrates using ab-initio calculations and analyzed the physical origin of their gap reduction. We also studied the effect of atomic dopants, in particular rare gases. Substantial band gap reduction has been observed, especially in the case of doping with Xe, due to both electronic and structural effects. Absorption spectra have been computed by solving the Bethe-Salpeter Equation [2] to gain a thourough insight into the optical properties of pure and doped tungsten trioxide. [1] Q. Mi, Y. Ping, Y. Li., B.S. Brunschwig, G. Galli, H B. Gray, N S. Lewis (preprint) [2]D. Rocca, D. Lu and G. Galli, J. Chem. Phys. 133, 164109 (2010)

  4. Applying accelerator mass spectrometry for low-level detection of complex engineered nanoparticles in biological media.

    PubMed

    Wang, Binghui; Jackson, George S; Yokel, Robert A; Grulke, Eric A

    2014-08-01

    Complex engineered nanoparticles (CENPs), which have different core and surface components, are being developed for medicinal, pharmaceutical and industrial applications. One of the key challenges for environmental health and safety assessments of CENPs is to identify and quantity their transformations in biological environments. This study reports the effects of in vivo exposure of citrate-coated nanoalumina with different rare isotope labels on each component. This CENP was dosed to the rat and accelerator mass spectrometry (AMS) was used to quantify (26)Al, (14)C, and their ratio in the dosing material and tissue samples. For CENPs detected in the liver, the rare isotope ratio, (14)C/(26)Al, was 87% of the dosing material's ratio. The citrate coating on the nanoalumina in the liver was stable or, if it degraded, its metabolites were incorporated with nearby tissues. However, in brain and bone where little alumina was detected, the rare isotope ratio greatly exceeded that of the dosing material. Therefore, in the animal, citrate dissociated from CENPs and redistributed to brain and bone. Tracking both the core and surface components by AMS presents a new approach for characterizing transformations of CENPs components in biological milieu or environments.

  5. Heat-flow properties of systems with alternate masses or alternate on-site potentials.

    PubMed

    Pereira, Emmanuel; Santana, Leonardo M; Ávila, Ricardo

    2011-07-01

    We address a central issue of phononics: the search of properties or mechanisms to manage the heat flow in reliable materials. We analytically study standard and simple systems modeling the heat flow in solids, namely, the harmonic, self-consistent harmonic and also anharmonic chains of oscillators, and we show an interesting insulating effect: While in the homogeneous models the heat flow decays as the inverse of the particle mass, in the chain with alternate masses it decays as the inverse of the square of the mass difference, that is, it decays essentially as the mass ratio (between the smaller and the larger one) for a large mass difference. A similar effect holds if we alternate on-site potentials instead of particle masses. The existence of such behavior in these different systems, including anharmonic models, indicates that it is a ubiquitous phenomenon with applications in the heat flow control.

  6. Optical properties of biomimetic probes engineered from erythrocytes

    NASA Astrophysics Data System (ADS)

    Burns, Joshua M.; Saager, Rolf; Majaron, Boris; Jia, Wangcun; Anvari, Bahman

    2017-01-01

    Light-activated theranostic materials offer a potential platform for optical imaging and phototherapeutic applications. We have engineered constructs derived from erythrocytes, which can be doped with the FDA-approved near infrared (NIR) chromophore, indocyanine green (ICG). We refer to these constructs as NIR erythrocyte-mimicking transducers (NETs). Herein, we investigated the effects of changing the NETs mean diameter from micron- (≈4 μm) to nano- (≈90 nm) scale, and the ICG concentration utilized in the fabrication of NETs from 5 to 20 μM on the resulting absorption and scattering characteristics of the NETs. Our approach consisted of integrating sphere-based measurements of light transmittance and reflectance, and subsequent utilization of these measurements in an inverse adding-doubling algorithm to estimate the absorption (μ a) and reduced scattering (μ s‧) coefficients of these NETs. For a given NETs diameter, values of μ a increased over the approximate spectral band of 630-860 nm with increasing ICG concentration. Micron-sized NETs produced the highest peak value of μ a when using ICG concentrations of 10 and 20 μM, and showed increased values of μ s‧ as compared to nano-sized NETs. Spectral profiles of μ s‧ for these NETs showed a trend consistent with Mie scattering behavior for spherical objects. For all NETs investigated, changing the ICG concentration minimally affected the scattering characteristics. A Monte Carlo-based model of light distribution showed that the presence of these NETs enhanced the fluence levels within simulated blood vessels. These results provide important data towards determining the appropriate light dosimetry parameters for an intended light-based biomedical application of NETs.

  7. Chitosan fibers with improved biological and mechanical properties for tissue engineering applications.

    PubMed

    Albanna, Mohammad Z; Bou-Akl, Therese H; Blowytsky, Oksana; Walters, Henry L; Matthew, Howard W T

    2013-04-01

    The low mechanical properties of hydrogel materials such as chitosan hinder their broad utility for tissue engineering applications. Previous research efforts improved the mechanical properties of chitosan fiber through chemical and physical modifications; however, unfavorable toxicity effects on cells were reported. In this paper, we report the preparation of chitosan fibers with improved mechanical and biocompatibility properties. The structure-property relationships of extruded chitosan fibers were explored by varying acetic acid (AA) concentration, ammonia concentration, annealing temperature and degree of heparin crosslinking. Results showed that optimizing AA concentration to 2vol% improved fiber strength and stiffness by 2-fold. Extruding chitosan solution into 25wt% of ammonia solution reduced fiber diameters and improved fiber strength by 2-fold and stiffness by 3-fold, due to an increase in crystallinity as confirmed by XRD. Fiber annealing further reduced fiber diameter and improved fiber strength and stiffness as temperature increased. Chitosan fibers crosslinked with heparin had increased diameter but lower strength and stiffness properties and higher breaking strain values. When individual parameters were combined, further improvement in fiber mechanical properties was achieved. All mechanically improved fibers and heparin crosslinked fibers promoted valvular interstitial cells (VIC) attachment and growth over 10 day cultures. Our results demonstrate the ability to substantially improve the mechanical properties of chitosan fibers without adversely affecting their biological properties. The investigated treatments offer numerous advantages over previous physical/chemical modifications and thus are expected to expand the utility of chitosan fibers with tunable mechanical properties in various tissue engineering applications.

  8. Mass

    SciTech Connect

    Quigg, Chris

    2007-12-05

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

  9. Real gas properties and Space Shuttle Main Engine fuel turbine performance prediction

    NASA Technical Reports Server (NTRS)

    Harloff, G. J.

    1987-01-01

    The H2/H2O mixture thermodynamic and transport properties variations for the Space Shuttle Main Engine (SSME) fuel turbine over a range of temperatures and pressures are examined. The variation of molecular viscosity, specific heat at constant pressure, and Prandtl number for the hydrogen/steam mixture are fitted using polynominal relationships for future turbine performance use. The mixture property variations are calculated using GASP and WASP computer programs. The air equivalent performance of the SSME fuel turbine is computed.

  10. Characterization of Gas-Phase Organics Using Proton Transfer Reaction Time-of-Flight Mass Spectrometry: Aircraft Turbine Engines.

    PubMed

    Kilic, Dogushan; Brem, Benjamin T; Klein, Felix; El-Haddad, Imad; Durdina, Lukas; Rindlisbacher, Theo; Setyan, Ari; Huang, Rujin; Wang, Jing; Slowik, Jay G; Baltensperger, Urs; Prevot, Andre S H

    2017-04-04

    Nonmethane organic gas emissions (NMOGs) from in-service aircraft turbine engines were investigated using a proton transfer reaction time-of-flight mass spectrometer (PTR-ToF-MS) at an engine test facility at Zurich Airport, Switzerland. Experiments consisted of 60 exhaust samples for seven engine types (used in commercial aviation) from two manufacturers at thrust levels ranging from idle to takeoff. Emission indices (EIs) for more than 200 NMOGs were quantified, and the functional group fractions (including acids, carbonyls, aromatics, and aliphatics) were calculated to characterize the exhaust chemical composition at different engine operation modes. Total NMOG emissions were highest at idling with an average EI of 7.8 g/kg fuel and were a factor of ∼40 lower at takeoff thrust. The relative contribution of pure hydrocarbons (particularly aromatics and aliphatics) of the engine exhaust decreased with increasing thrust while the fraction of oxidized compounds, for example, acids and carbonyls increased. Exhaust chemical composition at idle was also affected by engine technology. Older engines emitted a higher fraction of nonoxidized NMOGs compared to newer ones. Idling conditions dominated ground level organic gas emissions. Based on the EI determined here, we estimate that reducing idle emissions could substantially improve air quality near airports.

  11. Interface engineered multifunctional oxide thin films with optimized properties

    NASA Astrophysics Data System (ADS)

    Collins, Gregory Roy

    2010-06-01

    In our world today, energy has become one of the most valuable resources, in particular, renewable and clean energy sources. The research presented here represents an investigation into three separate areas of this topic. In thin film applications, the ordered structures as well as the inherent thinness of the films precludes the normal physics found in bulk materials. Characterizations of films of this type can provide information on molecular level charge transfer processes of the film layer materials since diffusive properties are minimal. With the control given by pulsed laser deposition methods, film and interface structure can be altered allowing for an examination of these effects on the materials properties. For the electrolyte and cathode materials, this equates to finding thermal and PO2 dependencies for electronic and ionic transport. For barium titanate, aside from the effects of oxygen vacancies, the interface quality between the electrodes and the ferroelectric material determines the effectiveness of energy transfer between these boundaries. That is, poor bonding characteristics or the formation of intermediate layers will introduce inconsistencies and (possibly) unwanted piezoelectric response properties of the material which could introduce parasitic dampening (resistance) of the mechanical vibrations of a piezoelectric transducer, altering its resonant characteristics. The clean reaction products and potential for high power outputs provide a strong impetus into investigations of fuel cell structures to improve their functionality. With conventional applications being dominated by high temperature (>700 °C) cells utilizing YSZ as an electrolyte medium, much gain can be made in efficiency through the lowering of cell operation temperature. The first part of my research focuses on the growth and characterization of a novel multilayered electrolyte structure consisting of alternating layers of GCO and YSZ for use in a medium temperature (400--600

  12. Hydrodynamic parameters modulate biochemical, histological, and mechanical properties of engineered cartilage.

    PubMed

    Bueno, Ericka M; Bilgen, Bahar; Barabino, Gilda A

    2009-04-01

    Functional engineered cartilage constructs represent a promising therapeutic approach for the replacement of damaged articular cartilage. The in vitro generation of cartilage tissue suitable for repair requires an understanding of the complex interrelationships between environmental cues, such as hydrodynamic forces, and tissue growth and development. In the present study, engineered cartilage constructs were cultivated in four well-defined hydrodynamic environments within a bioreactor, and correlations were established between construct ultrastructural and mechanical properties and key hydrodynamic parameters. Results suggest that even for similar composition, constructs may exhibit different mechanical properties due to differences in their ultrastructure that can be modulated by hydrodynamic parameters. For example, improved mechanical properties were observed in constructs that exhibited a thick fibrous outer capsule as a result of cultivation under increased hydrodynamic shear. In particular, uniformity in the contribution of the fluid velocity vectors (axial, radial, and tangential) to the total fluid velocity and shear stress were the hydrodynamic parameters that most affected the construct properties under investigation. The correlations identified here may be useful in the development of engineered tissue growth models that inform the design of bioreactor cultivation systems toward the production of clinically relevant engineered cartilage.

  13. Engineering support activities for the Apollo 17 Surface Electrical Properties Experiment.

    NASA Technical Reports Server (NTRS)

    Cubley, H. D.

    1972-01-01

    Description of the engineering support activities which were required to ensure fulfillment of objectives specified for the Apollo 17 SEP (Surface Electrical Properties) Experiment. Attention is given to procedural steps involving verification of hardware acceptability to the astronauts, computer simulation of the experiment hardware, field trials, receiver antenna pattern measurements, and the qualification test program.

  14. Fuel Property Effects on the Cold Startability of Navy High-Speed Diesel Engines.

    DTIC Science & Technology

    1985-12-01

    207 MAY 1 81%7I By A.F. Montemayor D W E.C. Owens J. P. Buckingham Belvoir Fuels and Lubricants Research Facility (SwRI) Southwest Research Institute...Property Effects on the Cold Startability of Navy High-Speed Diesel Engines (U) 12. PERSONAL AUTHORIS) Montemayor , A.F.; Owens, E.C.; Buckingham, J.P.; Jung

  15. Improving magnetic properties of MgB2 bulk superconductors by synthetic engine oil treatment

    NASA Astrophysics Data System (ADS)

    Taylan Koparan, E.; Savaskan, B.; Yanmaz, E.

    2016-08-01

    The present study focuses on the effects of standby time of the MgB2 samples immersed in synthetic engine oil on the critical current density (Jc(H)), magnetic field dependence of the pinning force density fp(b) and Tc performances of MgB2 bulk superconductors. Synthetic engine oil was used as a product which is cheap and a rich carbon source. Manufactured MgB2 pellet samples were immersed at different standby time of 30 min, 120 min, 300 min and 1440 min in synthetic engine oil after the first heating process. Finally, MgB2 samples immersed in synthetic engine oil were sintered at 1000 °C and kept for 15 min in Ar atmosphere. The critical current density of all of MgB2 samples immersed at different standby time in engine oil in whole field range was better than that of the pure MgB2 sample because of the number of the pinning centers. The MgB2 sample immersed at 300 min standby time in synthetic engine oil has the best performance compared to other samples. The Jc value for the pure sample is 2.0 × 103 A/cm2, whereas for the MgB2 sample immersed at 300 min standby time in engine oil the Jc is enhanced to 4.8 × 103A/cm2 at 5 K and 3 T. The superconducting transition temperature (Tc) did not change with the increasing standby time of the samples in synthetic engine oil at all. The best diamagnetic property was obtained from the sample which kept in synthetic engine oil for 300 min. Synthetic engine oil treatment results in remarkable improvement of the critical current density and pinning force performances of MgB2 superconductors. It was found that all MgB2 samples have a different pinning property at different measuring temperatures. Using synthetic engine oil as a product which is cheap and a rich carbon source in MgB2 bulk superconductors makes MgB2 samples immersed in synthetic engine oil a good candidate for industrial applications.

  16. Engineering the electronic properties of nanowires for device applications

    NASA Astrophysics Data System (ADS)

    Thelander, Claes

    2007-03-01

    Semiconductor nanowires have recently been recognized as a possible add-on technology to silicon CMOS. Successful integration of nanowires may push the miniaturization of components further and could also bring improved, and completely new, device functions to a chip. In particular, nanowires composed of III-V materials are of interest for applications as they benefit from a small and/or direct bandgap. We will present results from electrical measurements on InAs/InP nanowires grown by chemical beam epitaxy. Changes in the precursors fed to the growth chamber can be made to control the electronic properties of the grown material. In this way it is possible to create atomically sharp heterostructure interfaces, as well as to change the carrier concentration along the wire. The latter can be achieved by controlling the carbon incorporation from the In precursor. It will be shown that heterostructure nanowires can be used in memory cells, and also as single-electron transistors for electrostatic read-out of such cells. Finally, we will discuss the design and application of InAs nanowire-based field-effect transistors, where issues related to lateral and vertical processing of nanowires will be addressed.

  17. Online monitoring of mechanical properties of three-dimensional tissue engineered constructs for quality assessment

    NASA Astrophysics Data System (ADS)

    Reinwald, Yvonne; Bagnaninchi, Pierre O.; Yang, Ying; Baba Ismail, Yanny M.; El Haj, Alicia J.

    2016-03-01

    Mechanical preconditioning and mechanical properties of tissue engineered constructs are essential for their capability to regenerate damaged tissues. To online monitor the mechanical properties a hydrostatic pressure bioreactor was coupled with optical coherence tomography into a new image modality termed hydrostatic pressure optical coherence elastography (HP-OCE). HP-OCE was utilised to assess the properties of three-dimensional (3D) tissue constructs while being physically stimulated within the hydrostatic force bioreactor. Hydrogels have been infiltrated into porous rapid prototyped or salt-leached scaffolds to mimic heterogeneous mechanical properties of cell-seeded constructs. Variations of mechanical properties in the solid scaffolds and agarose gels with different gel concentrations as well as the presences of cells have been clearly delineated by HP-OCE. Results indicate that HP-OCE allows contactless real-time non-invasive monitoring of the mechanical properties of tissue constructs and the effect of physical stimulation on cellular activities.

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

    SciTech Connect

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

    2015-09-16

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

  19. Mass property identification - A comparison study between extended Kalman filter and neuro-filter approaches

    NASA Technical Reports Server (NTRS)

    Lam, Quang; Chipman, Richard; Sunkel, John

    1991-01-01

    Two algorithms, extended Kalman filter and neuro-filter, are formulated to perform mass property identification for the Space Station Freedom. Control moment gyros that are part of the Station's basic momentum management system are chosen to provide input excitation in the form of applied torques. These torques together with the measured angular body rate responses are supplied to the filters. From these data, both algorithms are shown to accurately identify the station mass properties when excitation levels are high and balanced between axes. The neuro-filter, however, is shown to be more robust and to perform well even with weakly persistent, unbalanced signals contaminated with noise.

  20. Apollo Soyuz Test Project Weights and Mass Properties Operational Management System

    NASA Technical Reports Server (NTRS)

    Collins, M. A., Jr.; Hischke, E. R.

    1975-01-01

    The Apollo Soyuz Test Project (ASTP) Weights and Mass Properties Operational Management System was established to assure a timely and authoritative method of acquiring, controlling, generating, and disseminating an official set of vehicle weights and mass properties data. This paper provides an overview of the system and its interaction with the various aspects of vehicle and component design, mission planning, hardware and software simulations and verification, and real-time mission support activities. The effect of vehicle configuration, design maturity, and consumables updates is discussed in the context of weight control.

  1. Dynamic Modeling Accuracy Dependence on Errors in Sensor Measurements, Mass Properties, and Aircraft Geometry

    NASA Technical Reports Server (NTRS)

    Grauer, Jared A.; Morelli, Eugene A.

    2013-01-01

    A nonlinear simulation of the NASA Generic Transport Model was used to investigate the effects of errors in sensor measurements, mass properties, and aircraft geometry on the accuracy of dynamic models identified from flight data. Measurements from a typical system identification maneuver were systematically and progressively deteriorated and then used to estimate stability and control derivatives within a Monte Carlo analysis. Based on the results, recommendations were provided for maximum allowable errors in sensor measurements, mass properties, and aircraft geometry to achieve desired levels of dynamic modeling accuracy. Results using other flight conditions, parameter estimation methods, and a full-scale F-16 nonlinear aircraft simulation were compared with these recommendations.

  2. Dielectric Property Enhancement in Polymer Composites with Engineered Interfaces

    NASA Astrophysics Data System (ADS)

    Krentz, Timothy Michael

    This thesis reports studies into the dielectric behavior of polymer composites filled with silica nanoparticles. The permittivity and dielectric breakdown strength (DBS) of these materials are critical to their performance in insulating applications such as high voltage power transmission. Until now, the mechanisms which lead to improvements in DBS in these systems have been poorly understood, in part because the effects of dispersion of the filler and the filler's surface electronic characteristics have been confused. The new surface modifications created in this thesis permit these two parameters to be addressed independently, leading to the hypothesis that nanocomposite dielectric materials exhibit DBS enhancement when electron avalanches are prevented from proceeding to reach a critical size capable of causing failure. The same control of dispersion and surface properties also lead to changes in the permittivity of the composite based upon the polarizability and trapping behavior of the filler. In this work, the dispersion and surface states of silica nanoparticles were independently controlled with two separate populations of surface molecules. Two matrix materials were studied, and in each system, a different, matrix-compatible long chain polymer is required to control dispersion. Conversely, a second population of short molecules is shown to be capable of creating electronic traps associated with the silica nanoparticle surface which lead to DBS enhancements largely independent of the matrix, indicating that the same failure mechanism is operating in both epoxy and polypropylene. Progressive variation in dispersion quality is attained with this surface modification scheme. This creates progressively smaller volumes of matrix polymer unaffected by the filler. This work shows that when these volumes approach and become smaller than the same scale as predicted for electron avalanches, the greatest changes in DBS are seen. Likewise, the plateau behavior of this

  3. Engineered Surface Properties of Porous Tungsten from Cryogenic Machining

    NASA Astrophysics Data System (ADS)

    Schoop, Julius Malte

    Porous tungsten is used to manufacture dispenser cathodes due to it refractory properties. Surface porosity is critical to functional performance of dispenser cathodes because it allows for an impregnated ceramic compound to migrate to the emitting surface, lowering its work function. Likewise, surface roughness is important because it is necessary to ensure uniform wetting of the molten impregnate during high temperature service. Current industry practice to achieve surface roughness and surface porosity requirements involves the use of a plastic infiltrant during machining. After machining, the infiltrant is baked and the cathode pellet is impregnated. In this context, cryogenic machining is investigated as a substitutionary process for the current plastic infiltration process. Along with significant reductions in cycle time and resource use, surface quality of cryogenically machined un-infiltrated (as-sintered) porous tungsten has been shown to significantly outperform dry machining. The present study is focused on examining the relationship between machining parameters and cooling condition on the as-machined surface integrity of porous tungsten. The effects of cryogenic pre-cooling, rake angle, cutting speed, depth of cut and feed are all taken into consideration with respect to machining-induced surface morphology. Cermet and Polycrystalline diamond (PCD) cutting tools are used to develop high performance cryogenic machining of porous tungsten. Dry and pre-heated machining were investigated as a means to allow for ductile mode machining, yet severe tool-wear and undesirable smearing limited the feasibility of these approaches. By using modified PCD cutting tools, high speed machining of porous tungsten at cutting speeds up to 400 m/min is achieved for the first time. Beyond a critical speed, brittle fracture and built-up edge are eliminated as the result of a brittle to ductile transition. A model of critical chip thickness ( hc ) effects based on cutting

  4. Biomechanical properties of the spinal cord: implications for tissue engineering and clinical translation.

    PubMed

    Bartlett, Richard D; Choi, David; Phillips, James B

    2016-10-01

    Spinal cord injury is a severely debilitating condition which can leave individuals paralyzed and suffering from autonomic dysfunction. Regenerative medicine may offer a promising solution to this problem. Previous research has focused primarily on exploring the cellular and biological aspects of the spinal cord, yet relatively little remains known about the biomechanical properties of spinal cord tissue. Given that a number of regenerative strategies aim to deliver cells and materials in the form of tissue-engineered therapies, understanding the biomechanical properties of host spinal cord tissue is important. We review the relevant biomechanical properties of spinal cord tissue and provide the baseline knowledge required to apply these important physical concepts to spinal cord tissue engineering.

  5. Diameter Versus Mass in the Development of the Orion Life Support Umbilical: A Case Study in Systems Engineering

    NASA Technical Reports Server (NTRS)

    Jordan, Nicole; Falconi, Eric; Barido, Richard; Lewis, John

    2009-01-01

    Systems engineering could also be called the art of compromise. At its heart, systems engineering seeks to find that solution which maximizes the utility of the system, usually compromising the performance of each individual subsystem. While seemingly straightforward, systems engineering methodology is complicated when the utility to be maximized is unclear and the costs to each individual subsystem are not - or not easily - quantifiable. In this paper, we explore one such systems engineering problem within the Constellation Program as a case study in applied systems engineering. During suited operations, astronauts within Orion will be connected to an umbilical to receive and return breathing gas. The pressure drop associated with this umbilical must be overcome by the Orion vehicle. A smaller umbilical, which is desirable for crew operations, means a higher pressure drop, resulting in additional mass and power for the vehicle. We outline the technical considerations in the development of this integrated system and discuss the method by which we reached the ultimate solution. This paper, while just one example of the kind of problem solving that happens every day, offers insight into what happens when the theories of systems engineering are put into practice.

  6. On-line analysis of diesel engine exhaust gases by selected ion flow tube mass spectrometry.

    PubMed

    Smith, David; Spanĕl, Patrik; Dabill, David; Cocker, John; Rajan, Bob

    2004-01-01

    Selected ion flow tube mass spectrometry (SIFT-MS) has been used to analyse on-line and in real time the exhaust gas emissions from a Caterpillar 3304 diesel engine under different conditions of load (idle and 50% of rated load) and speed (910, 1500 and 2200 rpm) using three types of fuel: an ultra-low-sulphur diesel, a rapeseed methyl ester and gas oil. SIFT-MS analyses of the alkanes, alkenes and aromatic hydrocarbons in the headspace of these fuels were also performed, but the headspace of the rapeseed methyl ester consists mainly of methanol and a compound with the molecular formula C4H8O. The exhaust gases were analysed for NO and NO2 using O2+* reagent ions and for HNO2 using H3O+ reagent ions. The following aldehydes and ketones in the exhaust gases were quantified by using the combination of H3O+ and NO+ reagent ions: formaldehyde, acetaldehyde, propenal, propanal, acetone, butanal, pentanal, butanone and pentanone. Formaldehyde, acetaldehyde and pentenal, all known respiratory irritants associated with sensitisation to asthma of workers exposed to diesel exhaust, are variously present within the range 100-2000 ppb. Hydrocarbons in the exhaust gases accessible to SIFT-MS analyses were also quantified as total concentrations of the various isomers of C3H4, C3H6, C4H6, C5H8, C5H10, C6H8, C6H10, C7H14, C6H6, C7H8, C8H10 and C9H12.

  7. Physicochemical and optical properties of combustion-generated particles from Ship Diesel Engines

    NASA Astrophysics Data System (ADS)

    Kim, H.; Jeong, S.; Jin, H. C.; Kim, J. Y.

    2015-12-01

    Shipping contributes significantly to the anthropogenic burden of particulate matter (PM), and is among the world's highest polluting combustion sources per fuel consumed. Moreover, ships are a highly concentrated source of pollutants which are emitted into clean marine environments (e.g., Artic region). Shipping utilizes heavy fuel oil (HFO) which is less distilled compared to fuels used on land and few investigations on shipping related PM properties are available. BC is one of the dominant combustion products of ship diesel engines and its chemical and microphysical properties have a significant impact on climate by influencing the amount of albedo reduction on bright surfaces such as in polar regions. We have carried out a campaign to characterize the PM emissions from medium-sized marine engines in Gunsan, Jeonbuk Institute of Automotive Technology. The properties of ship-diesel PM have characterized depending on (1) fuel sulfur content (HFO vs. ULSD) and (2) engine conditions (Running state vs. Idling state). Scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), energy-dispersive X-ray spectroscopy (EDX) equipped with HRTEM and Raman spectroscopy were used for physicochemical analysis. Optical properties, which are ultimately linked to the snow/ice albedo decrease impacting climate, were assessed as well. PM generated under high engine temperature conditions had typical features of soot, e.g., concentric circles comprised of closely packed graphene layers, however PM generated by the idling state at low combustion temperature was characterized by amorphous and droplet-like carbonaceous particles with no crystalline structure. Significant differences in optical properties depending on the combustion conditions were also observed. Particles from running conditions showed wavelength-independent absorbing properties, whereas the particles from idling conditions showed enhanced absorption at shorter wavelengths, which is

  8. Characteristic of blended fuel properties and engine cycle-to-cycle variations with butanol additive

    NASA Astrophysics Data System (ADS)

    Ali, Obed M.; Mamat, Rizalman; Abdullah, Nik R.; Abdullah, Abdul Adam

    2015-05-01

    Biodiesel fuel characteristics are one of the most important parameters that limited their application in diesel engines. Though biodiesel-diesel blended fuel can replace diesel satisfactorily at low blending ratios up to 20%, problems related to fuel property persist at high blending ratio. Hence, in the present study, the feasibility of biodiesel-diesel blended fuel B30 was investigated with respect to its properties and engine cyclic variations with increasing butanol additive. The blended fuel with additive were tested experimentally in a diesel engine and the in-cylinder pressure data were collected and analyzed using the coefficient of variation and wavelet power spectrum to evaluate the engine cyclic variations compared to diesel fuel engine test results. The fuel property test results showed slight improvement in density and acid value with significant reduction in viscosity when increasing butanol additive. Furthermore, the blended fuel pour point was reduced to -6 °C at 8% butanol additive. On the other hand, the energy content slightly affected with increasing butanol additive in the blend. From the wavelet power spectrum, it is observed that the short-period oscillations appear intermittently in pure blended fuel, while the long and intermediate-term periodicities tends to appear with increasing additive ratio. Moreover, the spectral power increased with an increase in the additive ratio indicating that the additive has a noticeable effect on increasing the cycle to cycle variation. The coefficient of variation of indicated mean effective pressure for B30 were found to be the lowest and increases with increasing additive ratios. Both the wavelet analysis and coefficient of variation results reveals that blended fuel B30 has engine cyclic variations comparable to diesel fuel with increasing butanol additive up to 4%.

  9. Gelatin Scaffolds with Controlled Pore Structure and Mechanical Property for Cartilage Tissue Engineering.

    PubMed

    Chen, Shangwu; Zhang, Qin; Nakamoto, Tomoko; Kawazoe, Naoki; Chen, Guoping

    2016-03-01

    Engineering of cartilage tissue in vitro using porous scaffolds and chondrocytes provides a promising approach for cartilage repair. However, nonuniform cell distribution and heterogeneous tissue formation together with weak mechanical property of in vitro engineered cartilage limit their clinical application. In this study, gelatin porous scaffolds with homogeneous and open pores were prepared using ice particulates and freeze-drying. The scaffolds were used to culture bovine articular chondrocytes to engineer cartilage tissue in vitro. The pore structure and mechanical property of gelatin scaffolds could be well controlled by using different ratios of ice particulates to gelatin solution and different concentrations of gelatin. Gelatin scaffolds prepared from ≥70% ice particulates enabled homogeneous seeding of bovine articular chondrocytes throughout the scaffolds and formation of homogeneous cartilage extracellular matrix. While soft scaffolds underwent cellular contraction, stiff scaffolds resisted cellular contraction and had significantly higher cell proliferation and synthesis of sulfated glycosaminoglycan. Compared with the gelatin scaffolds prepared without ice particulates, the gelatin scaffolds prepared with ice particulates facilitated formation of homogeneous cartilage tissue with significantly higher compressive modulus. The gelatin scaffolds with highly open pore structure and good mechanical property can be used to improve in vitro tissue-engineered cartilage.

  10. VAMP: A computer program for calculating volume, area, and mass properties of aerospace vehicles

    NASA Technical Reports Server (NTRS)

    Norton, P. J.; Glatt, C. R.

    1974-01-01

    A computerized procedure developed for analyzing aerospace vehicles evaluates the properties of elemental surface areas with specified thickness by accumulating and combining them with arbitrarily specified mass elements to form a complete evaluation. Picture-like images of the geometric description are capable of being generated.

  11. Aerosol properties and radiative forcing for three air masses transported in Summer 2011 to Sopot, Poland

    NASA Astrophysics Data System (ADS)

    Rozwadowska, Anna; Stachlewska, Iwona S.; Makuch, P.; Markowicz, K. M.; Petelski, T.; Strzałkowska, A.; Zieliński, T.

    2013-05-01

    Properties of atmospheric aerosols and solar radiation reaching the Earth's surface were measured during Summer 2011 in Sopot, Poland. Three cloudless days, characterized by different directions of incoming air-flows, which are typical transport pathways to Sopot, were used to estimate a radiative forcing due to aerosols present in each air mass.

  12. Estimation of engineering properties of selected tuffs by using grain/matrix ratio

    NASA Astrophysics Data System (ADS)

    Korkanç, Mustafa; Solak, Burak

    2016-08-01

    Petrographic properties of rocks substantially affect their physical and mechanical properties. In the present study, for the purpose of examining the relationship between the petrographic and geomechanical properties of pyroclastic rocks, fresh samples were taken from tuffs of different textural properties that have wide distribution in Cappadocia region. Experimental studies were conducted on 20 fresh samples to determine their engineering properties through petrographic examinations. Dry and saturated unit weights, water absorption by weight, effective porosity, capillary water absorption, slake durability index, P-wave velocity, point load index, uniaxial compressive strength and nail penetration index of the samples were determined. Higher geomechanical values were obtained from the samples of Kavak tuffs affected by hydromechanical alteration and by tuffs with high welded rates. On thin sections prepared with the fresh samples, petrographic studies were carried out by using a point counter with a polarizing microscope, and mineral composition, texture, void ratio, volcanic glass presence and state of these fragments within the rock, secondary mineral formation and opaque mineral presence were determined. Grain/matrix ratio (GMR) was calculated by using the ratios of phenocrysts, microlites, volcanic glass, voids and opaque minerals after point counting on thin sections. A potential relationship between the petrographic and geomechanical properties of fresh samples was tried to determine by counting correlation analysis. Such a relationship can be significantly and extensively suggestible for engineering applications. For this purpose, we used the poorly-welded Kavak and densely-welded Kızılkaya tuff samples in our study.

  13. Photoresponsive Polysaccharide-Based Hydrogels with Tunable Mechanical Properties for Cartilage Tissue Engineering.

    PubMed

    Giammanco, Giuseppe E; Carrion, Bita; Coleman, Rhima M; Ostrowski, Alexis D

    2016-06-15

    Photoresponsive hydrogels were obtained by coordination of alginate-acrylamide hybrid gels (AlgAam) with ferric ions. The photochemistry of Fe(III)-alginate was used to tune the chemical composition, mechanical properties, and microstructure of the materials upon visible light irradiation. The photochemical treatment also induced changes in the swelling properties and transport mechanism in the gels due to the changes in material composition and microstructure. The AlgAam gels were biocompatible and could easily be dried and rehydrated with no change in mechanical properties. These gels showed promise as scaffolds for cartilage tissue engineering, where the photochemical treatment could be used to tune the properties of the material and ultimately change the growth and extracellular matrix production of chondrogenic cells. ATDC5 cells cultured on the hydrogels showed a greater than 2-fold increase in the production of sulfated glycosaminoglycans (sGAG) in the gels irradiated for 90 min compared to the dark controls. Our method provides a simple photochemical tool to postsynthetically control and adjust the chemical and mechanical environment in these gels, as well as the pore microstructure and transport properties. By changing these properties, we could easily access different levels of performance of these materials as substrates for tissue engineering.

  14. Novel xylan-binding properties of an engineered family 4 carbohydrate-binding module.

    PubMed

    Cicortas Gunnarsson, Lavinia; Montanier, Cedric; Tunnicliffe, Richard B; Williamson, Mike P; Gilbert, Harry J; Nordberg Karlsson, Eva; Ohlin, Mats

    2007-09-01

    Molecular engineering of ligand-binding proteins is commonly used for identification of variants that display novel specificities. Using this approach to introduce novel specificities into CBMs (carbohydrate-binding modules) has not been extensively explored. Here, we report the engineering of a CBM, CBM4-2 from the Rhodothermus marinus xylanase Xyn10A, and the identification of the X-2 variant. As compared with the wild-type protein, this engineered module displays higher specificity for the polysaccharide xylan, and a lower preference for binding xylo-oligomers rather than binding the natural decorated polysaccharide. The mode of binding of X-2 differs from other xylan-specific CBMs in that it only has one aromatic residue in the binding site that can make hydrophobic interactions with the sugar rings of the ligand. The evolution of CBM4-2 has thus generated a xylan-binding module with different binding properties to those displayed by CBMs available in Nature.

  15. Properties and Star Formation Histories of Intermediate Redshift Dwarf Low-Mass Star-Forming Galaxies

    NASA Astrophysics Data System (ADS)

    Rodríguez-Muñoz, L.; Gallego, J.; Pacifici, C.; Tresse, L.; Charlot, S.; Gil de Paz, A.; Barro, G.; Villar, V.

    2017-03-01

    The epoch when low-mass star-forming galaxies (LMSFGs) form the bulk of their stellar mass is uncertain. While some models predict an early formation, others favor a delayed scenario until later ages of the Universe. We present improved constraints on the physical properties and star formation histories (SFHs) of a sample of intermediate redshift LMSFGs selected by their stellar mass or blue-compact-dwarf-like properties. Our work takes advantage of the deep UV-to-FIR photometric coverage available on the Extended-Chandra Deep Field South and our own dedicated deep VLT/VIMOS optical spectroscopy programs. On the one hand, we estimate the stellar mass (M_{*}), star formation rate (SFR), and SFH of each galaxy modeling its spectral energy distribution. We use a novel approach by Pacifici et al. 2012, that (1) consistently combines photometric (broad-band) and spectroscopic (emission line fluxes and equivalent widths) data, and (2) uses physically-motivated SFHs with non-uniform variations of the SFR as a function of time. On the other hand, we characterize the properties of their interstellar medium by analyzing the emission line features visible in the VIMOS spectroscopy. The final sample includes 91 spectroscopically confirmed LMSFGs (7.3 ≤ logM_{*}/M_{⊙} ≤ 9.5) at 0.3 mass, and high specific-SFR. Furthermore, they are characterized by strong emission lines, low metallicity, and an enhanced level of excitation. Our selection criterion based on mass gathers galaxies within a wide range of properties, and possibly, different evolutionary stages. Despite the individual differences, the average SFH that we obtain suggests a late and fast (˜2 Gyr prior their observation) assembly scenario for this type of system.

  16. Gas Turbine Engine Nonvolatile Particulate Matter Mass Emissions: Correlation with Smoke Number for Conventional and Alternative Fuel Blends.

    PubMed

    Christie, Simon; Lobo, Prem; Lee, David; Raper, David

    2017-01-17

    This study evaluates the relationship between the emissions parameters of smoke number (SN) and mass concentration of nonvolatile particulate matter (nvPM) in the exhaust of a gas turbine engine for a conventional Jet A-1 and a number of alternative fuel blends. The data demonstrate the significant impact of fuel composition on the emissions and highlight the magnitude of the fuel-induced uncertainty for both SN within the Emissions Data Bank as well as nvPM mass within the new regulatory standard under development. Notwithstanding these substantial differences, the data show that correlation between SN and nvPM mass concentration still adheres to the first order approximation (FOA3), and this agreement is maintained over a wide range of fuel compositions. Hence, the data support the supposition that the FOA3 is applicable to engines burning both conventional and alternative fuel blends without adaptation or modification. The chemical composition of the fuel is shown to impact mass and number concentration as well as geometric mean diameter of the emitted nvPM; however, the data do not support assertions that the emissions of black carbon with small mean diameter will result in significant deviations from FOA3.

  17. Ultrasound Imaging Techniques for Spatiotemporal Characterization of Composition, Microstructure, and Mechanical Properties in Tissue Engineering.

    PubMed

    Deng, Cheri X; Hong, Xiaowei; Stegemann, Jan P

    2016-08-01

    Ultrasound techniques are increasingly being used to quantitatively characterize both native and engineered tissues. This review provides an overview and selected examples of the main techniques used in these applications. Grayscale imaging has been used to characterize extracellular matrix deposition, and quantitative ultrasound imaging based on the integrated backscatter coefficient has been applied to estimating cell concentrations and matrix morphology in tissue engineering. Spectral analysis has been employed to characterize the concentration and spatial distribution of mineral particles in a construct, as well as to monitor mineral deposition by cells over time. Ultrasound techniques have also been used to measure the mechanical properties of native and engineered tissues. Conventional ultrasound elasticity imaging and acoustic radiation force imaging have been applied to detect regions of altered stiffness within tissues. Sonorheometry and monitoring of steady-state excitation and recovery have been used to characterize viscoelastic properties of tissue using a single transducer to both deform and image the sample. Dual-mode ultrasound elastography uses separate ultrasound transducers to produce a more potent deformation force to microscale characterization of viscoelasticity of hydrogel constructs. These ultrasound-based techniques have high potential to impact the field of tissue engineering as they are further developed and their range of applications expands.

  18. Passaged Adult Chondrocytes Can Form Engineered Cartilage with Functional Mechanical Properties: A Canine Model

    PubMed Central

    Ng, Kenneth W.; Lima, Eric G.; Bian, Liming; O'Conor, Christopher J.; Jayabalan, Prakash S.; Stoker, Aaron M.; Kuroki, Keiichi; Cook, Cristi R.; Ateshian, Gerard A.; Cook, James L.

    2010-01-01

    It was hypothesized that previously optimized serum-free culture conditions for juvenile bovine chondrocytes could be adapted to generate engineered cartilage with physiologic mechanical properties in a preclinical, adult canine model. Primary or passaged (using growth factors) adult chondrocytes from three adult dogs were encapsulated in agarose, and cultured in serum-free media with transforming growth factor-β3. After 28 days in culture, engineered cartilage formed by primary chondrocytes exhibited only small increases in glycosaminoglycan content. However, all passaged chondrocytes on day 28 elaborated a cartilage matrix with compressive properties and glycosaminoglycan content in the range of native adult canine cartilage values. A preliminary biocompatibility study utilizing chondral and osteochondral constructs showed no gross or histological signs of rejection, with all implanted constructs showing excellent integration with surrounding cartilage and subchondral bone. This study demonstrates that adult canine chondrocytes can form a mechanically functional, biocompatible engineered cartilage tissue under optimized culture conditions. The encouraging findings of this work highlight the potential for tissue engineering strategies using adult chondrocytes in the clinical treatment of cartilage defects. PMID:19845465

  19. Synthesis and Properties of Flexible Polyurethane Using Ferric Catalyst for Hypopharyngeal Tissue Engineering

    PubMed Central

    Shen, Zhisen; Wang, Jian; Lu, Dakai; Li, Qun; Zhou, Chongchang; Zhu, Yabin; Hu, Xiao

    2015-01-01

    Biodegradable polyurethane is an ideal candidate material to fabricate tissue engineered hypopharynx from its good mechanical properties and biodegradability. We thus synthesized a hydrophilic polyurethane via reactions among polyethylene glycol (PEG), e-caprolactone (e-CL) and hexamethylene diisocyanate (HDI), and thrihydroxymethyl propane (TMP). The product possessed a fast degradability due to its good wettability and good mechanical parameters with the elongations at break (137 ± 10%) and tensile strength (4.73 ± 0.46 MPa), which will make it a good matrix material for soft tissue like hypopharynx. Its biological properties were evaluated via in vitro and in vivo tests. The results showed that this hydrophilic polyurethane material can support hypopharyngeal fibroblast growth and owned good degradability and low inflammatory reaction in subcutaneous implantation. It will be proposed as the scaffold for hypopharyngeal tissue engineering research in our future study. PMID:26236737

  20. Geo-engineering evaluation of Termaber basalt rock mass for crushed stone aggregate and building stone from Central Ethiopia

    NASA Astrophysics Data System (ADS)

    Engidasew, Tesfaye Asresahagne; Barbieri, Giulio

    2014-11-01

    The geology of the central part of Ethiopia exhibits a variety of rock types that can potentially be developed for construction stone production, of which the most wide spread and important one is the Termaber basalt. Even though some preliminary work is done on these rocks towards construction material application, it remains largely that this resource is untouched and needs further scientific characterization for the use in large scale industrial application. Basaltic rocks have been widely used in many parts of the world as concrete aggregate and dimension stone for various civil structures. The present research study was carried out for Geo-engineering evaluation of Termaber basalt rock mass for crushed stone aggregate and building stone from Central Ethiopia (around Debre Birhan). The main objective of the present research study was to assess the general suitability of the Termaber basalt to be used as coarse aggregate for concrete mix and/or to utilize it as cut stone at industrial level. Only choice made with full knowledge of the basic characteristics of the material, of its performance and durability against the foreseen solicitations will ensure the necessary quality of the stone work and thereby a possibility to reach its intended service life. In order to meet out the objective of the present study, data from both field and laboratory were collected and analyzed. The field data included geological investigations based on different methods and sample collection while the laboratory work included, uniaxial compressive strength, ultrasonic pulse velocity, dynamic elasticity modulus, bulk density, water absorption, specific gravity, open porosity, aggregate impact value, petrographic examination and XRF, aggregate crushing value, Los Angeles abrasion value, sodium sulfate soundness, X-ray diffraction and alkali silica reactivity tests. The field and laboratory data were compiled and compared together to reveal the engineering performance of the rock mass in

  1. Physical Properties of the Narrow-line Region of Low-mass Active Galaxies

    NASA Astrophysics Data System (ADS)

    Ludwig, Randi R.; Greene, Jenny E.; Barth, Aaron J.; Ho, Luis C.

    2012-09-01

    We present spectroscopic observations of 27 active galactic nuclei (AGNs) with some of the lowest black hole (BH) masses known. We use the high spectral resolution and small aperture of our Keck data, taken with the Echellette Spectrograph and Imager, to isolate the narrow-line regions (NLRs) of these low-mass BHs. We investigate their emission-line properties and compare them with those of AGNs with higher-mass BHs. While we are unable to determine absolute metallicities, some of our objects plausibly represent examples of the low-metallicity AGNs described by Groves et al., based on their [N II]/Hα ratios and their consistency with the Kewley & Ellison mass-metallicity relation. We find tentative evidence for steeper far-UV spectral slopes in lower-mass systems. Overall, NLR emission lines in these low-mass AGNs exhibit trends similar to those seen in AGNs with higher-mass BHs, such as increasing blueshifts and broadening with increasing ionization potential. Additionally, we see evidence of an intermediate-line region whose intensity correlates with L/L Edd, as seen in higher-mass AGNs. We highlight the interesting trend that, at least in these low-mass AGNs, the [O III] equivalent width (EW) is highest in symmetric NLR lines with no blue wing. This trend of increasing [O III] EW with line symmetry could be explained by a high covering factor of lower-ionization gas in the NLR. In general, low-mass AGNs preserve many well-known trends in the structure of the NLR, while exhibiting steeper ionizing continuum slopes and somewhat lower gas-phase metallicities.

  2. Cloning Nacre's 3D Interlocking Skeleton in Engineering Composites to Achieve Exceptional Mechanical Properties.

    PubMed

    Zhao, Hewei; Yue, Yonghai; Guo, Lin; Wu, Juntao; Zhang, Youwei; Li, Xiaodong; Mao, Shengcheng; Han, Xiaodong

    2016-07-01

    Ceramic/polymer composite equipped with 3D interlocking skeleton (3D IL) is developed through a simple freeze-casting method, exhibiting exceptionally light weight, high strength, toughness, and shock resistance. Long-range crack energy dissipation enabled by 3D interlocking structure is considered as the primary reinforcing mechanism for such superior properties. The smart composite design strategy should hold a place in developing future structural engineering materials.

  3. Engineering of the band gap and optical properties of thin films of yttrium hydride

    SciTech Connect

    You, Chang Chuan; Mongstad, Trygve; Maehlen, Jan Petter; Karazhanov, Smagul

    2014-07-21

    Thin films of oxygen-containing yttrium hydride show photochromic effect at room temperature. In this work, we have studied structural and optical properties of the films deposited at different deposition pressures, discovering the possibility of engineering the optical band gap by variation of the oxygen content. In sum, the transparency of the films and the wavelength range of photons triggering the photochromic effect can be controlled by variation of the deposition pressure.

  4. Low band gap frequencies and multiplexing properties in 1D and 2D mass spring structures

    NASA Astrophysics Data System (ADS)

    Aly, Arafa H.; Mehaney, Ahmed

    2016-11-01

    This study reports on the propagation of elastic waves in 1D and 2D mass spring structures. An analytical and computation model is presented for the 1D and 2D mass spring systems with different examples. An enhancement in the band gap values was obtained by modeling the structures to obtain low frequency band gaps at small dimensions. Additionally, the evolution of the band gap as a function of mass value is discussed. Special attention is devoted to the local resonance property in frequency ranges within the gaps in the band structure for the corresponding infinite periodic lattice in the 1D and 2D mass spring system. A linear defect formed of a row of specific masses produces an elastic waveguide that transmits at the narrow pass band frequency. The frequency of the waveguides can be selected by adjusting the mass and stiffness coefficients of the materials constituting the waveguide. Moreover, we pay more attention to analyze the wave multiplexer and DE-multiplexer in the 2D mass spring system. We show that two of these tunable waveguides with alternating materials can be employed to filter and separate specific frequencies from a broad band input signal. The presented simulation data is validated through comparison with the published research, and can be extended in the development of resonators and MEMS verification.

  5. Strain engineering for mechanical properties in graphene nanoribbons revisited: The warping edge effect

    NASA Astrophysics Data System (ADS)

    Jiang, Jin-Wu

    2016-06-01

    We investigate the strain engineering and the edge effect for mechanical properties in graphene nanoribbons. The free edges of the graphene nanoribbons are warped due to compressive edge stresses. There is a structural transformation for the free edges from the three-dimensional warping configuration to the two-dimensional planar structure at the critical strain ɛc = 0.7%, at which the applied mechanical stress is equal to the intrinsic compressive edge stress. This structural transformation leads to step-like changes in several mechanical properties studied in the present work, including the Young's modulus, the Poisson's ratio, the quality factor of nanomechanical resonators, and the phonon edge mode.

  6. Tailoring the Spectroscopic Properties of Semiconductor Nanowires via Surface-Plasmon-Based Optical Engineering

    PubMed Central

    2014-01-01

    Semiconductor nanowires, due to their unique electronic, optical, and chemical properties, are firmly placed at the forefront of nanotechnology research. The rich physics of semiconductor nanowire optics arises due to the enhanced light–matter interactions at the nanoscale and coupling of optical modes to electronic resonances. Furthermore, confinement of light can be taken to new extremes via coupling to the surface plasmon modes of metal nanostructures integrated with nanowires, leading to interesting physical phenomena. This Perspective will examine how the optical properties of semiconductor nanowires can be altered via their integration with highly confined plasmonic nanocavities that have resulted in properties such as orders of magnitude faster and more efficient light emission and lasing. The use of plasmonic nanocavities for tailored optical absorption will also be discussed in order to understand and engineer fundamental optical properties of these hybrid systems along with their potential for novel applications, which may not be possible with purely dielectric cavities. PMID:25396030

  7. Engineering the Structure and Properties of DNA-Nanoparticle Superstructures Using Polyvalent Counterions.

    PubMed

    Chou, Leo Y T; Song, Fayi; Chan, Warren C W

    2016-04-06

    DNA assembly of nanoparticles is a powerful approach to control their properties and prototype new materials. However, the structure and properties of DNA-assembled nanoparticles are labile and sensitive to interactions with counterions, which vary with processing and application environment. Here we show that substituting polyamines in place of elemental counterions significantly enhanced the structural rigidity and plasmonic properties of DNA-assembled metal nanoparticles. These effects arose from the ability of polyamines to condense DNA and cross-link DNA-coated nanoparticles. We further used polyamine wrapped DNA nanostructures as structural templates to seed the growth of polymer multilayers via layer-by-layer assembly, and controlled the degree of DNA condensation, plasmon coupling efficiency, and material responsiveness to environmental stimuli by varying polyelectrolyte composition. These results highlight counterion engineering as a versatile strategy to tailor the properties of DNA-nanoparticle assemblies for various applications, and should be applicable to other classes of DNA nanostructures.

  8. Monitoring of the Physical and Chemical Properties of a Gasoline Engine Oil during Its Usage.

    PubMed

    Rahimi, Behnam; Semnani, Abolfazl; Nezamzadeh-Ejhieh, Alireza; Shakoori Langeroodi, Hamid; Hakim Davood, Massoud

    2012-01-01

    Physicochemical properties of a mineral-based gasoline engine oil have been monitored at 0, 500, 1000, 2000, 3500, 6000, 8500, and 11500 kilometer of operation. Tracing has been performed by inductively coupled plasma and some other techniques. At each series of measurements, the concentrations of twenty four elements as well as physical properties such as: viscosity at 40 and 100°C; viscosity index; flash point; pour point; specific gravity; color; total acid and base numbers; water content have been determined. The results are indicative of the decreasing trend in concentration of additive elements and increasing in concentration for wear elements. Different trends have been observed for various physical properties. The possible reasons for variations in physical and chemical properties have been discussed.

  9. Monitoring of the Physical and Chemical Properties of a Gasoline Engine Oil during Its Usage

    PubMed Central

    Rahimi, Behnam; Semnani, Abolfazl; Nezamzadeh-Ejhieh, Alireza; Shakoori Langeroodi, Hamid; Hakim Davood, Massoud

    2012-01-01

    Physicochemical properties of a mineral-based gasoline engine oil have been monitored at 0, 500, 1000, 2000, 3500, 6000, 8500, and 11500 kilometer of operation. Tracing has been performed by inductively coupled plasma and some other techniques. At each series of measurements, the concentrations of twenty four elements as well as physical properties such as: viscosity at 40 and 100°C; viscosity index; flash point; pour point; specific gravity; color; total acid and base numbers; water content have been determined. The results are indicative of the decreasing trend in concentration of additive elements and increasing in concentration for wear elements. Different trends have been observed for various physical properties. The possible reasons for variations in physical and chemical properties have been discussed. PMID:22567569

  10. Engineered particles demonstrate improved flow properties at elevated drug loadings for direct compression manufacturing.

    PubMed

    Trementozzi, Andrea N; Leung, Cheuk-Yui; Osei-Yeboah, Frederick; Irdam, Erwin; Lin, Yiqing; MacPhee, J Michael; Boulas, Pierre; Karki, Shyam B; Zawaneh, Peter N

    2017-03-08

    Optimizing powder flow and compaction properties are critical for ensuring a robust tablet manufacturing process. The impact of flow and compaction properties of the active pharmaceutical ingredient (API) becomes progressively significant for higher drug load formulations, and for scaling up manufacturing processes. This study demonstrated that flow properties of a powder blend can be improved through API particle engineering, without critically impacting blend tabletability at elevated drug loadings. In studying a jet milled API (D50=24μm) and particle engineered wet milled API (D50=70μm and 90μm), flow functions of all API lots were similarly poor despite the vast difference in average particle size (ffc<4). This finding strays from the common notion that powder flow properties are directly correlated to particle size distribution. Upon adding excipients, however, clear trends in flow functions based on API particle size were observed. Wet milled API blends had a much improved flow function (ffc>10) compared with the jet milled API blends. Investigation of the compaction properties of both wet and jet milled powder blends also revealed that both jet and wet milled material produced robust tablets at the drug loadings used. The ability to practically demonstrate this uncommon observation that similarly poor flowing APIs can lead to a marked difference upon blending is important for pharmaceutical development. It is especially important in early phase development during API selection, and is advantageous particularly when material-sparing techniques are utilized.

  11. Strain Engineering of Octahedral Rotations and Physical Properties of SrRuO3 Films.

    PubMed

    Lu, Wenlai; Song, Wendong; Yang, Ping; Ding, Jun; Chow, Gan Moog; Chen, Jingsheng

    2015-05-28

    Strain engineering is an effective way to modify functional properties of thin films. Recently, the importance of octahedral rotations in pervoskite films has been recognized in discovering and designing new functional phases. Octahedral behavior of SrRuO3 film as a popular electrode in heterostructured devices is of particular interest for its probable interfacial coupling of octahedra with the functional overlayers. Here we report the strain engineering of octahedral rotations and physical properties that has been achieved in SrRuO3 films in response to the substrate-induced misfit strains of almost the same amplitude but of opposite signs. It shows that the compressively strained film on NdGaO3 substrate displays a rotation pattern of a tetragonal phase whilst the tensilely strained film on KTaO3 substrate has the rotation pattern of the bulk orthorhombic SrRuO3 phase. In addition, the compressively strained film displays a perpendicular magnetic anisotropy while the tensilely strained film has the magnetic easy axis lying in the film plane. The results show the prospect of strain engineered octahedral architecture in producing desired property and novel functionality in the class of perovskite material.

  12. Strain Engineering of Octahedral Rotations and Physical Properties of SrRuO3 Films

    NASA Astrophysics Data System (ADS)

    Lu, Wenlai; Song, Wendong; Yang, Ping; Ding, Jun; Chow, Gan Moog; Chen, Jingsheng

    2015-05-01

    Strain engineering is an effective way to modify functional properties of thin films. Recently, the importance of octahedral rotations in pervoskite films has been recognized in discovering and designing new functional phases. Octahedral behavior of SrRuO3 film as a popular electrode in heterostructured devices is of particular interest for its probable interfacial coupling of octahedra with the functional overlayers. Here we report the strain engineering of octahedral rotations and physical properties that has been achieved in SrRuO3 films in response to the substrate-induced misfit strains of almost the same amplitude but of opposite signs. It shows that the compressively strained film on NdGaO3 substrate displays a rotation pattern of a tetragonal phase whilst the tensilely strained film on KTaO3 substrate has the rotation pattern of the bulk orthorhombic SrRuO3 phase. In addition, the compressively strained film displays a perpendicular magnetic anisotropy while the tensilely strained film has the magnetic easy axis lying in the film plane. The results show the prospect of strain engineered octahedral architecture in producing desired property and novel functionality in the class of perovskite material.

  13. Mass properties calibration of the NASA Langley low frequency vibration test apparatus

    NASA Technical Reports Server (NTRS)

    Javeed, Mehzad; Russell, James W.

    1995-01-01

    This report presents a description and calibration results of the modified NASA Langley Low Frequency Vibration Test Apparatus. The description includes both the suspension system and the data acquisition system. The test apparatus consists of a 2 inch thick, 21 inch diameter aluminum plate that is suspended from an advanced suspension system using a 40 foot long cable system. The test apparatus employed three orthogonally aligned pairs of Sundstrand QA-700 servo accelerometers that can measure accelerations as low as 1 micro-g. The calibration involved deriving the mass and moments of inertia of the test platform from measured input forces and measured acceleration responses. The derived mass and moments were compared to test platform mass properties obtained initially from measurements with a special mass properties instrument. Results of the calibration tests showed that using the product of the test apparatus mass and the measured accelerations, the disturbance force at the center of gravity (CG) can be determined within 4 percent on all three axes. Similarly the disturbance moments about the X, Y, and Z axes can be determined within 5 percent by using the product of the measured moments of inertia and the angular accelerations about the X, Y, and Z axes.

  14. The impact of low levels of collagen IX and pyridinoline on the mechanical properties of in vitro engineered cartilage.

    PubMed

    Yan, Dan; Zhou, Guangdong; Zhou, Xu; Liu, Wei; Zhang, Wen Jie; Luo, Xusong; Zhang, Lu; Jiang, Ting; Cui, Lei; Cao, Yilin

    2009-02-01

    The application of in vitro engineered cartilage has become a promising approach to repair cartilage defects. Nevertheless, the poor mechanical properties of in vitro engineered cartilage limit its potential for clinical applications. Studies have shown that the extracellular matrix (ECM) components are strongly correlated with the mechanical strength of engineered cartilage, but it remains unclear which components play a key role in determining the mechanical property of engineered cartilage. To address this issue, quantitative analyses of cartilage-specific components among native cartilage, in vivo and in vitro engineered cartilages were performed, and the correlation between various ECM molecules and Young's modulus was further analyzed. The results showed that many ECM molecules, such as highly sulphated glycosaminoglycan (GAG), collagens II, IX, and pyridinoline (PYR), contributed to the mechanical strength of cartilages. Further comparison between in vitro engineered cartilage and stress-stimulated in vitro engineered cartilage, known to have stronger mechanical properties, showed that only collagen IX and PYR, but not GAG and collagen II, were the key factors determining the mechanical properties of in vitro engineered cartilage. These results indicate that in vitro environment lacks the niche for enhancing collagen crosslinking that is mediated by collagen IX and PYR during cartilage formation. Thus, the discovery provides a clue for engineering strong cartilage in vitro in the future by enhancing the levels of these two molecules.

  15. Recombination of protein fragments: a promising approach toward engineering proteins with novel nanomechanical properties.

    PubMed

    Balamurali, M M; Sharma, Deepak; Chang, Anderson; Khor, Dingyue; Chu, Ricky; Li, Hongbin

    2008-10-01

    Combining single molecule atomic force microscopy (AFM) and protein engineering techniques, here we demonstrate that we can use recombination-based techniques to engineer novel elastomeric proteins by recombining protein fragments from structurally homologous parent proteins. Using I27 and I32 domains from the muscle protein titin as parent template proteins, we systematically shuffled the secondary structural elements of the two parent proteins and engineered 13 hybrid daughter proteins. Although I27 and I32 are highly homologous, and homology modeling predicted that the hybrid daughter proteins fold into structures that are similar to that of parent protein, we found that only eight of the 13 daughter proteins showed beta-sheet dominated structures that are similar to parent proteins, and the other five recombined proteins showed signatures of the formation of significant alpha-helical or random coil-like structure. Single molecule AFM revealed that six recombined daughter proteins are mechanically stable and exhibit mechanical properties that are different from the parent proteins. In contrast, another four of the hybrid proteins were found to be mechanically labile and unfold at forces that are lower than the approximately 20 pN, as we could not detect any unfolding force peaks. The last three hybrid proteins showed interesting duality in their mechanical unfolding behaviors. These results demonstrate the great potential of using recombination-based approaches to engineer novel elastomeric protein domains of diverse mechanical properties. Moreover, our results also revealed the challenges and complexity of developing a recombination-based approach into a laboratory-based directed evolution approach to engineer novel elastomeric proteins.

  16. Synchrotron based mass spectrometry to investigate the molecular properties of mineral-organic associations

    SciTech Connect

    Liu, Suet Yi; Kleber, Markus; Takahashi, Lynelle K.; Nico, Peter; Keiluweit, Marco; Ahmed, Musahid

    2013-04-01

    Soil organic matter (OM) is important because its decay drives life processes in the biosphere. Analysis of organic compounds in geological systems is difficult because of their intimate association with mineral surfaces. To date there is no procedure capable of quantitatively separating organic from mineral phases without creating artifacts or mass loss. Therefore, analytical techniques that can (a) generate information about both organic and mineral phases simultaneously and (b) allow the examination of predetermined high-interest regions of the sample as opposed to conventional bulk analytical techniques are valuable. Laser Desorption Synchrotron Postionization (synchrotron-LDPI) mass spectrometry is introduced as a novel analytical tool to characterize the molecular properties of organic compounds in mineral-organic samples from terrestrial systems, and it is demonstrated that when combined with Secondary Ion Mass Spectrometry (SIMS), can provide complementary information on mineral composition. Mass spectrometry along a decomposition gradient in density fractions, verifies the consistency of our results with bulk analytical techniques. We further demonstrate that by changing laser and photoionization energies, variations in molecular stability of organic compounds associated with mineral surfaces can be determined. The combination of synchrotron-LDPI and SIMS shows that the energetic conditions involved in desorption and ionization of organic matter may be a greater determinant of mass spectral signatures than the inherent molecular structure of the organic compounds investigated. The latter has implications for molecular models of natural organic matter that are based on mass spectrometric information.

  17. Physical Properties Of The NLR In Low-mass Active Galaxies

    NASA Astrophysics Data System (ADS)

    Ludwig, Randi R.; Greene, J. E.; Barth, A. J.; Ho, L. C.

    2012-01-01

    We present high-resolution spectroscopic observations of 27 active galactic nuclei (AGN) with black hole masses M_BH < 2 × 10^6 M⊙. We investigate their narrow emission line properties and compare them with those of AGN with higher mass black holes. While we are unable to determine absolute metallicities, these low-luminosity objects plausibly represent AGN with sub-solar metallicities, based on their [N II]/Hα ratios and their consistency with the Kewley et al. (2008) mass-metallicity relation. We find that these low-mass AGN have UV continuum slopes similar to those of more massive AGN based on their He II/Hβ ratio, similar blueshifts and broadening in their narrow lines with respect to ionization potential, and we see evidence of an intermediate line region whose intensity correlates with L/L_Edd in these objects. In contrast to higher-mass AGN, we find that the low-mass AGN have selectively high narrow line EWs when [O III] shows no blue wing, which could be explained by a high covering factor of lower ionization gas in the narrow-line region of objects with symmetric emission lines.

  18. Determination and Assessment of Parameters Influencing Rock Mass Cavability in Block Caving Mines Using the Probabilistic Rock Engineering System

    NASA Astrophysics Data System (ADS)

    Rafiee, Ramin; Ataei, Mohammad; Khalokakaie, Reza; Jalali, Seyed Mohammad Esmaeil; Sereshki, Farhang

    2015-05-01

    Mining methods such as block caving or sublevel caving rely on the characteristics of the rock mass to cave efficiently to fulfill an economical production. The identification of influencing parameters and cavability assessment are, thus, a prime geotechnical focus for all potential caving projects. In the caving operation, many factors, such as natural and induced factors, affect the caving performance. In this study, after discussing the caving process and identifying all effective parameters, the interaction matrix based on the rock engineering system (RES) is introduced to study the influencing parameters in rock mass cavability. The interaction matrix analyzes the interrelationship between the parameters affecting rock engineering activities. As the interaction matrix codes are not unique, probabilistic coding can be performed non-deterministically, allowing consideration of uncertainties in the RES analysis. As a result, the parameters with the highest probability of being dominant or subordinate, and also the parameters with the highest probability of being interactive, are introduced. The proposed approach could be a simple but efficient tool in the evaluation of the parameters affecting the cavability of rock mass in block caving mines and, hence, useful in decision-making under uncertainties.

  19. Characterization of real gas properties for space shuttle main engine fuel turbine and performance calculations

    NASA Technical Reports Server (NTRS)

    Harloff, G. J.

    1986-01-01

    Real thermodynamic and transport properties of hydrogen, steam, the SSME mixture, and air are developed. The SSME mixture properties are needed for the analysis of the space shuttle main engine fuel turbine. The mixture conditions for the gases, except air, are presented graphically over a temperature range from 800 to 1200 K, and a pressure range from 1 to 500 atm. Air properties are given over a temperature range of 320 to 500 K, which are within the bounds of the thermodynamics programs used, in order to provide mixture data which is more easily checked (than H2/H2O). The real gas property variation of the SSME mixture is quantified. Polynomial expressions, needed for future computer analysis, for viscosity, Prandtl number, and thermal conductivity are given for the H2/H2O SSME fuel turbine mixture at a pressure of 305 atm over a range of temperatures from 950 to 1140 K. These conditions are representative of the SSME turbine operation. Performance calculations are presented for the space shuttle main engine (SSME) fuel turbine. The calculations use the air equivalent concept. Progress towards obtaining the capability to evaluate the performance of the SSME fuel turbine, with the H2/H2O mixture, is described.

  20. Emissions from diesel versus biodiesel fuel used in a CRDI SUV engine: PM mass and chemical composition.

    PubMed

    Gangwar, Jitendra; Gupta, Tarun; Gupta, Sudhir; Agarwal, Avinash K

    2011-07-01

    The diesel tailpipe emissions typically undergo substantial physical and chemical transformations while traveling through the tailpipe, which tend to modify the original characteristics of the diesel exhaust. Most of the health-related attention for diesel exhaust has focused on the carcinogenic potential of inhaled exhaust components, particularly the highly respirable diesel particulate matter (DPM). In the current study, parametric investigations were made using a modern automotive common rail direct injection (CRDI) sports utility vehicle (SUV) diesel engine operated at different loads at constant engine speed (2400 rpm), employing diesel and 20% biodiesel blends (B20) produced from karanja oil. A partial flow dilution tunnel was employed to measure the mass of the primary particulates from diesel and biodiesel blend on a 47-mm quartz substrate. This was followed by chemical analysis of the particulates collected on the substrate for benzene-soluble organic fraction (BSOF) (marker of toxicity). BSOF results showed decrease in its level with increasing engine load for both diesel and biodiesel. In addition, real-time measurements for organic carbon/elemental carbon (OC/EC), and polycyclic aromatic hydrocarbons (PAHs) (marker of toxicity) were carried out on the diluted primary exhaust coming out of the partial flow dilution tunnel. PAH concentrations were found to be the maximum at 20% rated engine load for both the fuels. The collected particulates from diesel and biodiesel-blend exhaust were also analyzed for concentration of trace metals (marker of toxicity), which revealed some interesting results.

  1. First-principles investigation of electronic structure, effective carrier masses, and optical properties of ferromagnetic semiconductor CdCr2S4

    NASA Astrophysics Data System (ADS)

    Xu-Hui, Zhu; Xiang-Rong, Chen; Bang-Gui, Liu

    2016-05-01

    The electronic structures, the effective masses, and optical properties of spinel CdCr2S4 are studied by using the full-potential linearized augmented planewave method and a modified Becke-Johnson exchange functional within the density-functional theory. Most importantly, the effects of the spin-orbit coupling (SOC) on the electronic structures and carrier effective masses are investigated. The calculated band structure shows a direct band gap. The electronic effective mass and the hole effective mass are analytically determined by reproducing the calculated band structures near the BZ center. SOC substantially changes the valence band top and the hole effective masses. In addition, we calculated the corresponding optical properties of the spinel structure CdCr2S4. These should be useful to deeply understand spinel CdCr2S4 as a ferromagnetic semiconductor for possible semiconductor spintronic applications. Project supported by the Joint Fund of the National Natural Science Foundation of China and the China Academy of Engineering Physics (Grant Nos. U1430117 and U1230201).

  2. The Mass Distribution and Assembly of the Milky Way from the Properties of the Magellanic Clouds

    SciTech Connect

    Busha, Michael T.; Marshall, Philip J.; Wechsler, Risa H.; Klypin, Anatoly; Primack, Joel; /UC, Santa Cruz, Phys. Dept.

    2012-02-29

    We present a new measurement of the mass of the Milky Way (MW) based on observed properties of its largest satellite galaxies, the Magellanic Clouds (MCs), and an assumed prior of a {Lambda}CDM universe. The large, high-resolution Bolshoi cosmological simulation of this universe provides a means to statistically sample the dynamical properties of bright satellite galaxies in a large population of dark matter halos. The observed properties of the MCs, including their circular velocity, distance from the center of the MW, and velocity within the MW halo, are used to evaluate the likelihood that a given halo would have each or all of these properties; the posterior probability distribution function (PDF) for any property of the MW system can thus be constructed. This method provides a constraint on the MW virial mass, 1.2{sup +0.7} - {sub 0.4}(stat.){sup +0.3} - {sub 0.3}(sys.) x 10{sup 12} M {circle_dot} (68% confidence), which is consistent with recent determinations that involve very different assumptions. In addition, we calculate the posterior PDF for the density profile of the MW and its satellite accretion history. Although typical satellites of 10{sup 12} M {circle_dot} halos are accreted over a wide range of epochs over the last 10 Gyr, we find a {approx}72% probability that the MCs were accreted within the last Gyr, and a 50% probability that they were accreted together.

  3. THE MASS DISTRIBUTION AND ASSEMBLY OF THE MILKY WAY FROM THE PROPERTIES OF THE MAGELLANIC CLOUDS

    SciTech Connect

    Busha, Michael T.; Marshall, Philip J.; Wechsler, Risa H.; Klypin, Anatoly; Primack, Joel E-mail: pjm@slac.stanford.edu E-mail: aklypin@nmsu.edu

    2011-12-10

    We present a new measurement of the mass of the Milky Way (MW) based on observed properties of its largest satellite galaxies, the Magellanic Clouds (MCs), and an assumed prior of a {Lambda}CDM universe. The large, high-resolution Bolshoi cosmological simulation of this universe provides a means to statistically sample the dynamical properties of bright satellite galaxies in a large population of dark matter halos. The observed properties of the MCs, including their circular velocity, distance from the center of the MW, and velocity within the MW halo, are used to evaluate the likelihood that a given halo would have each or all of these properties; the posterior probability distribution function (PDF) for any property of the MW system can thus be constructed. This method provides a constraint on the MW virial mass, 1.2{sup +0.7}{sub -0.4} (stat.){sup +0.3}{sub -0.3} (sys.) Multiplication-Sign 10{sup 12} M{sub Sun} (68% confidence), which is consistent with recent determinations that involve very different assumptions. In addition, we calculate the posterior PDF for the density profile of the MW and its satellite accretion history. Although typical satellites of 10{sup 12} M{sub Sun} halos are accreted over a wide range of epochs over the last 10 Gyr, we find a {approx}72% probability that the MCs were accreted within the last Gyr, and a 50% probability that they were accreted together.

  4. Pulsating low-mass white dwarfs in the frame of new evolutionary sequences. I. Adiabatic properties

    NASA Astrophysics Data System (ADS)

    Córsico, A. H.; Althaus, L. G.

    2014-09-01

    Context. Many low-mass white dwarfs with masses M∗/M⊙ ≲ 0.45, including the so-called extremely low-mass white dwarfs (M∗/M⊙ ≲ 0.20 - 0.25), have recently been discovered in the field of our Galaxy through dedicated photometric surveys. The subsequent discovery of pulsations in some of them has opened the unprecedented opportunity of probing the internal structure of these ancient stars. Aims: We present a detailed adiabatic pulsational study of these stars based on full evolutionary sequences derived from binary star evolution computations. The main aim of this study is to provide a detailed theoretical basis of reference for interpreting present and future observations of variable low-mass white dwarfs. Methods: Our pulsational analysis is based on a new set of He-core white-dwarf models with masses ranging from 0.1554 to 0.4352 M⊙ derived by computing the non-conservative evolution of a binary system consisting of an initially 1 M⊙ ZAMS star and a 1.4 M⊙ neutron star. We computed adiabatic radial (ℓ = 0) and non-radial (ℓ = 1,2) p and g modes to assess the dependence of the pulsational properties of these objects on stellar parameters such as the stellar mass and the effective temperature, as well as the effects of element diffusion. Results: We found that for white dwarf models with masses below ~ 0.18 M⊙, g modes mainly probe the core regions and p modes the envelope, therefore pulsations offer the opportunity of constraining both the core and envelope chemical structure of these stars via asteroseismology. For models with M∗ ≳ 0.18 M⊙, on the other hand, g modes are very sensitive to the He/H compositional gradient and therefore can be used as a diagnostic tool for constraining the H envelope thickness. Because both types of objects have not only very distinct evolutionary histories (according to whether the progenitor stars have experienced CNO-flashes or not), but also have strongly different pulsation properties, we propose to

  5. The Effect of Scale on the Mechanical Properties of Jointed Rock Masses

    SciTech Connect

    Heuze, F E

    2004-05-24

    These notes were prepared for presentation at the Defense Threat Reduction Agency's (DTRA) Hard Target Research and Analysis Center (HTRAC), at the occasion of a short course held on June 14-15, 2004. The material is intended for analysts who must evaluate the geo-mechanical characteristics of sites of interest, in order to provide appropriate input to calculations of ground shock effects on underground facilities in rock masses. These analysts are associated with the Interagency Geotechnical Assessment Team (IGAT). Because geological discontinuities introduce scale effects on the mechanical properties of rock formations, these large-scale properties cannot be estimated on the basis of tests on small cores.

  6. Microstructure and mechanical properties of Ti-40 mass % Nb alloy after megaplastic deformation effect

    NASA Astrophysics Data System (ADS)

    Sharkeev, Yurii P.; Eroshenko, Anna Yu.; Glukhov, Ivan A.; Sun, Zeming; Zhu, Qifang; Danilov, Vladimir I.; Tolmachev, Alexei I.

    2015-10-01

    The microstructure and mechanical properties of Ti alloy contained 40 mass % Nb at megaplastic deformation effect is described. It was proved that the deformation effect including the multiple abc-pressing and multi-pass rolling and further pre-recrystallizing annealing enhances the formation of ultra-fine grained structures with mean element size of 0.3 μm or less, involving stable (β + α)-phase composition and metastable nanosized ω-phase in the alloy. This, in its turn, significantly improves the mechanical properties and simultaneously preserves low elastic modulus level.

  7. Dependence of Dynamic Modeling Accuracy on Sensor Measurements, Mass Properties, and Aircraft Geometry

    NASA Technical Reports Server (NTRS)

    Grauer, Jared A.; Morelli, Eugene A.

    2013-01-01

    The NASA Generic Transport Model (GTM) nonlinear simulation was used to investigate the effects of errors in sensor measurements, mass properties, and aircraft geometry on the accuracy of identified parameters in mathematical models describing the flight dynamics and determined from flight data. Measurements from a typical flight condition and system identification maneuver were systematically and progressively deteriorated by introducing noise, resolution errors, and bias errors. The data were then used to estimate nondimensional stability and control derivatives within a Monte Carlo simulation. Based on these results, recommendations are provided for maximum allowable errors in sensor measurements, mass properties, and aircraft geometry to achieve desired levels of dynamic modeling accuracy. Results using additional flight conditions and parameter estimation methods, as well as a nonlinear flight simulation of the General Dynamics F-16 aircraft, were compared with these recommendations

  8. Understanding the microstructure and properties of components fabricated by laser engineered net shaping (LENS)

    SciTech Connect

    GRIFFITH,MICHELLE L.; ENSZ,MARK T.; PUSKAR,JOSEPH D.; ROBINO,CHARLES V.; BROOKS,JOHN A.; PHILLIBER,JOEL A.; SMUGERESKY,JOHN E.; HOFMEISTER,W.H.

    2000-05-18

    Laser Engineered Net Shaping (LENS) is a novel manufacturing process for fabricating metal parts directly from Computer Aided Design (CAD) solid models. The process is similar to rapid prototyping technologies in its approach to fabricate a solid component by layer additive methods. However, the LENS technology is unique in that fully dense metal components with material properties that are similar to that of wrought materials can be fabricated. The LENS process has the potential to dramatically reduce the time and cost required realizing functional metal parts. In addition, the process can fabricate complex internal features not possible using existing manufacturing processes. The real promise of the technology is the potential to manipulate the material fabrication and properties through precision deposition of the material, which includes thermal behavior control, layered or graded deposition of multi-materials, and process parameter selection. This paper describes the authors' research to understand solidification aspects, thermal behavior, and material properties for laser metal deposition technologies.

  9. Unified low-parametrical equation of state for engineering calculations of thermodynamic properties of substances

    NASA Astrophysics Data System (ADS)

    Kaplun, Alexander; Meshalkin, Arkadiy

    2014-08-01

    The new simple semi empirical equation of state for description of P-ρ-T data of "normal" substances was specified. New equation of state has 10 individual adjustable coefficients and it describes thermal properties of gas, liquid and fluid in the main with the accuracy within the error of experimental data, except of critical region. The caloric properties and the speed of sound of argon, nitrogen and carbon dioxide were calculated with the help of known thermodynamic equations and in general divergences between calculated and tabular caloric data do not exceed the experimental error. New equation can be used for engineering calculations at the deficit of experimental data, especially on the caloric properties of substances.

  10. Properties of high-energy isoscalar monopole excitations in medium-heavy mass spherical nuclei

    SciTech Connect

    Gorelik, M. L. Shlomo, Sh. Tulupov, B. A. Urin, M. H.

    2015-07-15

    The recently developed particle-hole dispersive optical model is applied to describe properties of high-energy isoscalar monopole excitations in medium-heavy mass spherical nuclei. In particular, the double transition density averaged over the energy of the isoscalar monopole excitations is considered for {sup 208}Pb in a wide energy interval, which includes the isoscalar giant monopole resonance and its overtone. The energy-averaged strength functions of these resonances are also analyzed.

  11. Development of Chitosan Scaffolds with Enhanced Mechanical Properties for Intestinal Tissue Engineering Applications.

    PubMed

    Zakhem, Elie; Bitar, Khalil N

    2015-10-13

    Massive resections of segments of the gastrointestinal (GI) tract lead to intestinal discontinuity. Functional tubular replacements are needed. Different scaffolds were designed for intestinal tissue engineering application. However, none of the studies have evaluated the mechanical properties of the scaffolds. We have previously shown the biocompatibility of chitosan as a natural material in intestinal tissue engineering. Our scaffolds demonstrated weak mechanical properties. In this study, we enhanced the mechanical strength of the scaffolds with the use of chitosan fibers. Chitosan fibers were circumferentially-aligned around the tubular chitosan scaffolds either from the luminal side or from the outer side or both. Tensile strength, tensile strain, and Young's modulus were significantly increased in the scaffolds with fibers when compared with scaffolds without fibers. Burst pressure was also increased. The biocompatibility of the scaffolds was maintained as demonstrated by the adhesion of smooth muscle cells around the different kinds of scaffolds. The chitosan scaffolds with fibers provided a better candidate for intestinal tissue engineering. The novelty of this study was in the design of the fibers in a specific alignment and their incorporation within the scaffolds.

  12. Development of Chitosan Scaffolds with Enhanced Mechanical Properties for Intestinal Tissue Engineering Applications

    PubMed Central

    Zakhem, Elie; Bitar, Khalil N.

    2015-01-01

    Massive resections of segments of the gastrointestinal (GI) tract lead to intestinal discontinuity. Functional tubular replacements are needed. Different scaffolds were designed for intestinal tissue engineering application. However, none of the studies have evaluated the mechanical properties of the scaffolds. We have previously shown the biocompatibility of chitosan as a natural material in intestinal tissue engineering. Our scaffolds demonstrated weak mechanical properties. In this study, we enhanced the mechanical strength of the scaffolds with the use of chitosan fibers. Chitosan fibers were circumferentially-aligned around the tubular chitosan scaffolds either from the luminal side or from the outer side or both. Tensile strength, tensile strain, and Young’s modulus were significantly increased in the scaffolds with fibers when compared with scaffolds without fibers. Burst pressure was also increased. The biocompatibility of the scaffolds was maintained as demonstrated by the adhesion of smooth muscle cells around the different kinds of scaffolds. The chitosan scaffolds with fibers provided a better candidate for intestinal tissue engineering. The novelty of this study was in the design of the fibers in a specific alignment and their incorporation within the scaffolds. PMID:26473937

  13. Fuel properties and engine performance of biodiesel from waste cooking oil collected in Dhaka city

    NASA Astrophysics Data System (ADS)

    Islam, R. B.; Islam, R.; Uddin, M. N.; Ehsan, Md.

    2016-07-01

    Waste cooking oil can be a potential source of biodiesel that has least effect on the edible oil consumption. Increasing number of hotel-restaurants and more active monitoring by health authorities have increased the generation of waste cooking oil significantly in densely populated cities like Dhaka. If not used or disposed properly, waste cooking oil itself may generate lot of environmental issues. In this work, waste cooking oils from different restaurants within Dhaka City were collected and some relevant properties of these waste oils were measured. Based on the samples studied one with the highest potential as biodiesel feed was identified and processed for engine performance. Standard trans-esterification process was used to produce biodiesel from the selected waste cooking oil. Biodiesel blends of B20 and B40 category were made and tested on a single cylinder direct injection diesel engine. Engine performance parameters included - bhp, bsfc and exhaust emission for rated and part load conditions. Results give a quantitative assessment of the potential of using biodiesel from waste cooking oil as fuel for diesel engines in Bangladesh.

  14. Mass-transfer properties of insulin on core-shell and fully porous stationary phases.

    PubMed

    Lambert, Nándor; Kiss, Ibolya; Felinger, Attila

    2014-10-31

    The mass-transfer properties of three superficially-porous packing materials, with 2.6 and 3.6μm particle and 1.9, 2.6, and 3.2μm inner core diameter, respectively, were investigated and compared with those of fully porous packings with similar particle properties. Several sources of band spreading in the chromatographic bed have been identified and studied according to the general rate model of chromatography. Besides the axial dispersion in the stream of the mobile phase, and the external mass transfer resistance, the intraparticle diffusion was studied in depth. The first absolute and the second central moments of the peaks of human insulin, over a wide range of mobile phase velocities were measured and used for the calculation of the mass-transfer coefficients. The experimental data were also analyzed using the stochastic or molecular dynamic model of Giddings and Eyring. The dissimilarities of the mass-transfer observed in the different columns were identified and evaluated.

  15. Mass property control of a spin stabilized spacecraft with restrictive mission and weight constraints

    NASA Technical Reports Server (NTRS)

    Lang, W. E.; Ardvini, C.

    1985-01-01

    In the primary experiment of the spin stabilized San Marco D/L spacecraft, the drag effects on a light spherical shell coupled to a relatively massive center body will be measured. To achieve the precise mass property control, the centroids of both the shell and the center body must coincide with each other and with the center of pressure of the shell. Precise spin balancing is needed for launch and orbital stability, and the deployable antennas need accurate alignment. Corrective measures, developed after the preliminary mass measurements showed flaws in the mass property control, are described in detail. Inertia booms and a yo-yo despin system were developed as add-on units, spin balance measurements about all three geometric axes were used to define weight minimized correction within the outer shell envelope, and boom tip mass differentials were optimized for the most favorable inertia ratio margin achievable within the mission weight constraints. The weight versus orbital lifetime trade-offs were also considered.

  16. Emissions of NOx, particle mass and particle numbers from aircraft main engines, APU's and handling equipment at Copenhagen Airport

    NASA Astrophysics Data System (ADS)

    Winther, Morten; Kousgaard, Uffe; Ellermann, Thomas; Massling, Andreas; Nøjgaard, Jacob Klenø; Ketzel, Matthias

    2015-01-01

    This paper presents a detailed emission inventory for NOx, particle mass (PM) and particle numbers (PN) for aircraft main engines, APU's and handling equipment at Copenhagen Airport (CPH) based on time specific activity data and representative emission factors for the airport. The inventory has a high spatial resolution of 5 m × 5 m in order to be suited for further air quality dispersion calculations. Results are shown for the entire airport and for a section of the airport apron area ("inner apron") in focus. The methodology presented in this paper can be used to quantify the emissions from aircraft main engines, APU and handling equipment in other airports. For the entire airport, aircraft main engines is the largest source of fuel consumption (93%), NOx, (87%), PM (61%) and PN (95%). The calculated fuel consumption [NOx, PM, PN] shares for APU's and handling equipment are 5% [4%, 8%, 5%] and 2% [9%, 31%, 0%], respectively. At the inner apron area for handling equipment the share of fuel consumption [NOx, PM, PN] are 24% [63%, 75%, 2%], whereas APU and main engines shares are 43% [25%, 19%, 54%], and 33% [11%, 6%, 43%], respectively. The inner apron NOx and PM emission levels are high for handling equipment due to high emission factors for the diesel fuelled handling equipment and small for aircraft main engines due to small idle-power emission factors. Handling equipment is however a small PN source due to the low number based emission factors. Jet fuel sulphur-PM sensitivity calculations made in this study with the ICAO FOA3.0 method suggest that more than half of the PM emissions from aircraft main engines at CPH originate from the sulphur content of the fuel used at the airport. Aircraft main engine PN emissions are very sensitive to the underlying assumptions. Replacing this study's literature based average emission factors with "high" and "low" emission factors from the literature, the aircraft main engine PN emissions were estimated to change with a

  17. Tandem Mass Spectrum Sequencing: An Alternative to Database Search Engines in Shotgun Proteomics.

    PubMed

    Muth, Thilo; Rapp, Erdmann; Berven, Frode S; Barsnes, Harald; Vaudel, Marc

    2016-01-01

    Protein identification via database searches has become the gold standard in mass spectrometry based shotgun proteomics. However, as the quality of tandem mass spectra improves, direct mass spectrum sequencing gains interest as a database-independent alternative. In this chapter, the general principle of this so-called de novo sequencing is introduced along with pitfalls and challenges of the technique. The main tools available are presented with a focus on user friendly open source software which can be directly applied in everyday proteomic workflows.

  18. Tuning the optical, magnetic, and electrical properties of ReSe2 by nanoscale strain engineering.

    PubMed

    Yang, Shengxue; Wang, Cong; Sahin, Hasan; Chen, Hui; Li, Yan; Li, Shu-Shen; Suslu, Aslihan; Peeters, Francois M; Liu, Qian; Li, Jingbo; Tongay, Sefaattin

    2015-03-11

    Creating materials with ultimate control over their physical properties is vital for a wide range of applications. From a traditional materials design perspective, this task often requires precise control over the atomic composition and structure. However, owing to their mechanical properties, low-dimensional layered materials can actually withstand a significant amount of strain and thus sustain elastic deformations before fracture. This, in return, presents a unique technique for tuning their physical properties by "strain engineering". Here, we find that local strain induced on ReSe2, a new member of the transition metal dichalcogenides family, greatly changes its magnetic, optical, and electrical properties. Local strain induced by generation of wrinkle (1) modulates the optical gap as evidenced by red-shifted photoluminescence peak, (2) enhances light emission, (3) induces magnetism, and (4) modulates the electrical properties. The results not only allow us to create materials with vastly different properties at the nanoscale, but also enable a wide range of applications based on 2D materials, including strain sensors, stretchable electrodes, flexible field-effect transistors, artificial-muscle actuators, solar cells, and other spintronic, electromechanical, piezoelectric, photonic devices.

  19. Engineering the Mechanical Properties of Monolayer Graphene Oxide at the Atomic Level.

    PubMed

    Soler-Crespo, Rafael A; Gao, Wei; Xiao, Penghao; Wei, Xiaoding; Paci, Jeffrey T; Henkelman, Graeme; Espinosa, Horacio D

    2016-07-21

    The mechanical properties of graphene oxide (GO) are of great importance for applications in materials engineering. Previous mechanochemical studies of GO typically focused on the influence of the degree of oxidation on the mechanical behavior. In this study, using density functional-based tight binding simulations, validated using density functional theory simulations, we reveal that the deformation and failure of GO are strongly dependent on the relative concentrations of epoxide (-O-) and hydroxyl (-OH) functional groups. Hydroxyl groups cause GO to behave as a brittle material; by contrast, epoxide groups enhance material ductility through a mechanically driven epoxide-to-ether functional group transformation. Moreover, with increasing epoxide group concentration, the strain to failure and toughness of GO significantly increases without sacrificing material strength and stiffness. These findings demonstrate that GO should be treated as a versatile, tunable material that may be engineered by controlling chemical composition, rather than as a single, archetypical material.

  20. Rheological Properties of Cross-Linked Hyaluronan–Gelatin Hydrogels for Tissue Engineering

    PubMed Central

    Vanderhooft, Janssen L.; Alcoutlabi, Mataz; Magda, Jules J.; Prestwich, Glenn D.

    2009-01-01

    Hydrogels that mimic the natural extracellular matrix (ECM) are used in three-dimensional cell culture, cell therapy, and tissue engineering. A semi-synthetic ECM based on cross-linked hyaluronana offers experimental control of both composition and gel stiffness. The mechanical properties of the ECM in part determine the ultimate cell phenotype. We now describe a rheological study of synthetic ECM hydrogels with storage shear moduli that span three orders of magnitude, from 11 to 3 500 Pa, a range important for engineering of soft tissues. The concentration of the chemically modified HA and the cross-linking density were the main determinants of gel stiffness. Increase in the ratio of thiol-modified gelatin reduced gel stiffness by diluting the effective concentration of the HA component. PMID:18839402

  1. Using nonlinear optimization methods to reverse engineer liner material properties from EFP tests

    SciTech Connect

    Murphy, M.J.; Baker, E.L.

    1995-02-27

    The utility of variable metric nonlinear optimization methods for reverse engineering liner material constitutive modeling parameters is described. We use an effective new code created by coupling the nonlinear optimization code NLQPEB with the DYNA2D finite element hydrocode. The optimization code determines the ``best`` set of liner material properties by running DYNA2D in a loop, varying the liner model constitutive parameters, and minimizing the difference between the EFP profiles of the calculation and experiment. The results of four different EFP warhead tests with the same copper liner material are used to determine material parameters for the Steinberg-Guinan, Johnson-Cook, & Armstrong-Zerilli models. In a companion paper we describe the successful application of this methodology to the forward engineering of liner contours to achieve desired EFP shapes. The methodology of utilizing a coupled optimization/finite element code provides a significant improvement in warhead designs and the warhead design process.

  2. Ethnobotany/ethnopharmacology and mass bioprospecting: issues on intellectual property and benefit-sharing.

    PubMed

    Soejarto, D D; Fong, H H S; Tan, G T; Zhang, H J; Ma, C Y; Franzblau, S G; Gyllenhaal, C; Riley, M C; Kadushin, M R; Pezzuto, J M; Xuan, L T; Hiep, N T; Hung, N V; Vu, B M; Loc, P K; Dac, L X; Binh, L T; Chien, N Q; Hai, N V; Bich, T Q; Cuong, N M; Southavong, B; Sydara, K; Bouamanivong, S; Ly, H M; Thuy, Tran Van; Rose, W C; Dietzman, G R

    2005-08-22

    Ethnobotany/ethnopharmacology has contributed to the discovery of many important plant-derived drugs. Field explorations to seek and document indigenous/traditional medical knowledge (IMK/TMK), and/or the biodiversity with which the IMK/TMK is attached, and its conversion into a commercialized product is known as bioprospecting or biodiversity prospecting. When performed in a large-scale operation, the effort is referred to as mass bioprospecting. Experiences from the mass bioprospecting efforts undertaken by the United States National Cancer Institute, the National Cooperative Drug Discovery Groups (NCDDG) and the International Cooperative Biodiversity Groups (ICBG) programs demonstrate that mass bioprospecting is a complex process, involving expertise from diverse areas of human endeavors, but central to it is the Memorandum of Agreement (MOA) that recognizes issues on genetic access, prior informed consent, intellectual property and the sharing of benefits that may arise as a result of the effort. Future mass bioprospecting endeavors must take heed of the lessons learned from past and present experiences in the planning for a successful mass bioprospecting venture.

  3. Chondroprotective supplementation promotes the mechanical properties of injectable scaffold for human nucleus pulposus tissue engineering.

    PubMed

    Foss, Berit L; Maxwell, Thomas W; Deng, Ying

    2014-01-01

    A result of intervertebral disc (IVD) degeneration, the nucleus pulposus (NP) is no longer able to withstand applied load leading to pain and disability. The objective of this study is to fabricate a tissue-engineered injectable scaffold with chondroprotective supplementation in vitro to improve the mechanical properties of a degenerative NP. Tissue-engineered scaffolds were fabricated using different concentrations of alginate and calcium chloride and mechanically evaluated. Fabrication conditions were based on structural and mechanical resemblance to the native NP. Chondroprotective supplementation, glucosamine (GCSN) and chondroitin sulfate (CS), were added to scaffolds at concentrations of 0:0µg/mL (0:0-S), 125:100µg/mL (125:100-S), 250:200µg/mL (250:200-S), and 500:400µg/mL (500:400-S), GCSN and CS, respectively. Scaffolds were used to fabricate tissue-engineered constructs through encapsulation of human nucleus pulposus cells (HNPCs). The tissue-engineered constructs were collected at days 1, 14, and 28 for biochemical and biomechanical evaluations. Confocal microscopy showed HNPC viability and rounded morphology over the 28 day period. MTT analysis resulted in significant increases in cell proliferation for each group. Collagen type II ELISA quantification and compressive aggregate moduli (HA) showed increasing trends for both 250:200-S and the 500:400-S groups on Day 28 with significantly greater HA compared to 0:0-S group. Glycosaminoglycan and water content decreased for all groups. Results indicate the increased mechanical properties of the 250:200-S and the 500:400-S was due to production of a functional matrix. This study demonstrated potential for a chondroprotective supplemented injectable scaffold to restore biomechanical function of a degenerative disc through the production of a mechanically functional matrix.

  4. Fuel property effects on USAF gas turbine engine combustors and afterburners

    NASA Technical Reports Server (NTRS)

    Reeves, C. M.

    1984-01-01

    Since the early 1970s, the cost and availability of aircraft fuel have changed drastically. These problems prompted a program to evaluate the effects of broadened specification fuels on current and future aircraft engine combustors employed by the USAF. Phase 1 of this program was to test a set of fuels having a broad range of chemical and physical properties in a select group of gas turbine engine combustors currently in use by the USAF. The fuels ranged from JP4 to Diesel Fuel number two (DF2) with hydrogen content ranging from 14.5 percent down to 12 percent by weight, density ranging from 752 kg/sq m to 837 kg/sq m, and viscosity ranging from 0.830 sq mm/s to 3.245 sq mm/s. In addition, there was a broad range of aromatic content and physical properties attained by using Gulf Mineral Seal Oil, Xylene Bottoms, and 2040 Solvent as blending agents in JP4, JP5, JP8, and DF2. The objective of Phase 2 was to develop simple correlations and models of fuel effects on combustor performance and durability. The major variables of concern were fuel chemical and physical properties, combustor design factors, and combustor operating conditions.

  5. Improving the mechanical properties of collagen-based membranes using silk fibroin for corneal tissue engineering.

    PubMed

    Long, Kai; Liu, Yang; Li, Weichang; Wang, Lin; Liu, Sa; Wang, Yingjun; Wang, Zhichong; Ren, Li

    2015-03-01

    Although collagen with outstanding biocompatibility has promising application in corneal tissue engineering, the mechanical properties of collagen-based scaffolds, especially suture retention strength, must be further improved to satisfy the requirements of clinical applications. This article describes a toughness reinforced collagen-based membrane using silk fibroin. The collagen-silk fibroin membranes based on collagen [silk fibroin (w/w) ratios of 100:5, 100:10, and 100:20] were prepared by using silk fibroin and cross-linking by 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide. These membranes were analyzed by scanning electron microscopy and their optical property, and NaCl and tryptophan diffusivity had been tested. The water content was found to be dependent on the content of silk fibroin, and CS10 membrane (loading 10 wt % of silk fibroin) performed the optimal mechanical properties. Also the suture experiments have proved CS10 has high suture retention strength, which can be sutured in rabbit eyes integrally. Moreover, the composite membrane proved good biocompatibility for the proliferation of human corneal epithelial cells in vitro. Lamellar keratoplasty shows that CS10 membrane promoted complete epithelialization in 35 ± 5 days, and their transparency is restored quickly in the first month. Corneal rejection reaction, neovascularization, and keratoconus are not observed. The composite films show potential for use in the field of corneal tissue engineering.

  6. Metrological traceability of the measured values of properties of engineering materials

    NASA Astrophysics Data System (ADS)

    Roebben, G.; Linsinger, T.; Lamberty, A.; Emons, H.

    2010-04-01

    Global comparability of the measured values of material properties is based on some fundamental metrological concepts. These concepts are either already widely implemented in current procedures for materials testing or they are being further developed and increasingly accepted and used. An important aspect of the comparability of measurement results is metrological traceability. This paper aims at illustrating with practical examples how to apply the concept of metrological traceability as defined in ISO/IEC Guide 99:2007, known also as the VIM (International Vocabulary of Metrology), in the field of engineering material properties. VIM distinguishes three different types of references for traceability: either to a system of units, such as the SI, to a measurement procedure or to a physical measurement standard. For each approach, an example is given in the field of engineering material properties, including appropriate traceability statements and means to achieve the traceability. The role of certified reference materials is highlighted, as well as practical consequences of traceability requirements for the design of reference material certification projects.

  7. Synthesis and Engineering Materials Properties of Fluid Phase Chemical Hydrogen Storage Materials for Automotive Applications

    SciTech Connect

    Choi, Young Joon; Westman, Matthew P.; Karkamkar, Abhijeet J.; Chun, Jaehun; Ronnebro, Ewa

    2015-09-01

    Among candidates for chemical hydrogen storage in PEM fuel cell automotive applications, ammonia borane (AB, NH3BH3) is considered to be one of the most promising materials due to its high practical hydrogen content of 14-16 wt%. This material is selected as a surrogate chemical for a hydrogen storage system. For easier transition to the existing infrastructure, a fluid phase hydrogen storage material is very attractive and thus, we investigated the engineering materials properties of AB in liquid carriers for a chemical hydrogen storage slurry system. Slurries composed of AB and high temperature liquids were prepared by mechanical milling and sonication in order to obtain stable and fluidic properties. Volumetric gas burette system was adopted to observe the kinetics of the H2 release reactions of the AB slurry and neat AB. Viscometry and microscopy were employed to further characterize slurries engineering properties. Using a tip-sonication method we have produced AB/silicone fluid slurries at solid loadings up to 40wt% (6.5wt% H2) with viscosities less than 500cP at 25°C.

  8. Hydrogen exchange-mass spectrometry measures stapled peptide conformational dynamics and predicts pharmacokinetic properties.

    PubMed

    Shi, Xiangguo Eric; Wales, Thomas E; Elkin, Carl; Kawahata, Noriyuki; Engen, John R; Annis, D Allen

    2013-12-03

    Peptide drugs have traditionally suffered from poor pharmacokinetic properties due to their conformational flexibility and the interaction of proteases with backbone amide bonds. "Stapled Peptides" are cyclized using an all-hydrocarbon cross-linking strategy to reinforce their α-helical conformation, yielding improved protease resistance and drug-like properties. Here we demonstrate that hydrogen exchange-mass spectrometry (HX-MS) effectively probes the conformational dynamics of Stapled Peptides derived from the survivin-borealin protein-protein interface and predicts their susceptibility to proteolytic degradation. In Stapled Peptides, amide exchange was reduced by over five orders-of-magnitude versus the native peptide sequence depending on staple placement. Furthermore, deuteration kinetics correlated directly with rates of proteolysis to reveal the optimal staple placement for improved drug properties.

  9. Application of native-state electrospray mass spectrometry to identify zinc-binding sites on engineered hemoglobin.

    PubMed

    Lippincott, J; Fattor, T J; Lemon, D D; Apostol, I

    2000-09-10

    We report the utility of native-state mass spectrometry to detect zinc ion binding to the engineered hemoglobin rHb52. Various preparations of this recombinant hemoglobin had significantly different oxygen affinities. Detailed characterization of denatured globins did not show any difference between analyzed hemoglobin molecules. However, when solutions of intact hemoglobin pseudotetramers were analyzed by native-state electrospray mass spectrometry, a significant shift in the mass spectrum was observed, indicating labile modification of hemoglobin. Using collision-induced dissociation (CID), we found a mass gain of 63 Da located on the beta-globin. EDTA treatment of modified hemoglobin prior to the infusion removed the modification and restored the predicted oxygen affinity. Ion-trap fragmentation of the +8 charged ion of modified beta-globin showed a neutral loss of 96+/-1 Da, consistent with neutral loss of zinc sulfide. These findings indicated zinc binding to the beta-globin through a cysteine residue. Involvement of Cys93 was confirmed by kinetics of cysteine residue reactivity with dithiodipyridine and peptide mapping. Presence of zinc was confirmed by ICP-MS metal analysis.

  10. Engineering biodegradable polyester elastomers with antioxidant properties to attenuate oxidative stress in tissues

    PubMed Central

    van Lith, R.; Gregory, E.K.; Yang, J.; Kibbe, M.R.; Ameer, G.A.

    2014-01-01

    Oxidative stress plays an important role in the limited biological compatibility of many biomaterials due to inflammation, as well as in various pathologies including atherosclerosis and restenosis as a result of vascular interventions. Engineering antioxidant properties into a material is therefore a potential avenue to improve the biocompatibility of materials, as well as to locally attenuate oxidative stress-related pathologies. Moreover, biodegradable polymers that have antioxidant properties built into their backbone structure have high relative antioxidant content and may provide prolonged, continuous attenuation of oxidative stress while the polymer or its degradation products are present. In this report, we describe the synthesis of poly(1,8-octanediol-co-citrate-co-ascorbate) (POCA), a citric-acid based biodegradable elastomer with native, intrinsic antioxidant properties. The in vitro antioxidant activity of POCA as well as its effects on vascular cells in vitro and in vivo were studied. Antioxidant properties investigated included scavenging of free radicals, iron chelation and the inhibition of lipid peroxidation. POCA reduced reactive oxygen species generation in cells after an oxidative challenge and protected cells from oxidative stress-induced cell death. Importantly, POCA antioxidant properties remained present upon degradation. Vascular cells cultured on POCA showed high viability, and POCA selectively inhibited smooth muscle cell proliferation, while supporting endothelial cell proliferation. Finally, preliminary data on POCA-coated ePTFE grafts showed reduced intimal hyperplasia when compared to standard ePTFE grafts. This biodegradable, intrinsically antioxidant polymer may be useful for tissue engineering application where oxidative stress is a concern. PMID:24976244

  11. Engineering biodegradable polyester elastomers with antioxidant properties to attenuate oxidative stress in tissues.

    PubMed

    van Lith, Robert; Gregory, Elaine K; Yang, Jian; Kibbe, Melina R; Ameer, Guillermo A

    2014-09-01

    Oxidative stress plays an important role in the limited biological compatibility of many biomaterials due to inflammation, as well as in various pathologies including atherosclerosis and restenosis as a result of vascular interventions. Engineering antioxidant properties into a material is therefore a potential avenue to improve the biocompatibility of materials, as well as to locally attenuate oxidative stress-related pathologies. Moreover, biodegradable polymers that have antioxidant properties built into their backbone structure have high relative antioxidant content and may provide prolonged, continuous attenuation of oxidative stress while the polymer or its degradation products are present. In this report, we describe the synthesis of poly(1,8-octanediol-co-citrate-co-ascorbate) (POCA), a citric-acid based biodegradable elastomer with native, intrinsic antioxidant properties. The in vitro antioxidant activity of POCA as well as its effects on vascular cells in vitro and in vivo were studied. Antioxidant properties investigated included scavenging of free radicals, iron chelation and the inhibition of lipid peroxidation. POCA reduced reactive oxygen species generation in cells after an oxidative challenge and protected cells from oxidative stress-induced cell death. Importantly, POCA antioxidant properties remained present upon degradation. Vascular cells cultured on POCA showed high viability, and POCA selectively inhibited smooth muscle cell proliferation, while supporting endothelial cell proliferation. Finally, preliminary data on POCA-coated ePTFE grafts showed reduced intimal hyperplasia when compared to standard ePTFE grafts. This biodegradable, intrinsically antioxidant polymer may be useful for tissue engineering application where oxidative stress is a concern.

  12. Estimating mass properties of dinosaurs using laser imaging and 3D computer modelling.

    PubMed

    Bates, Karl T; Manning, Phillip L; Hodgetts, David; Sellers, William I

    2009-01-01

    Body mass reconstructions of extinct vertebrates are most robust when complete to near-complete skeletons allow the reconstruction of either physical or digital models. Digital models are most efficient in terms of time and cost, and provide the facility to infinitely modify model properties non-destructively, such that sensitivity analyses can be conducted to quantify the effect of the many unknown parameters involved in reconstructions of extinct animals. In this study we use laser scanning (LiDAR) and computer modelling methods to create a range of 3D mass models of five specimens of non-avian dinosaur; two near-complete specimens of Tyrannosaurus rex, the most complete specimens of Acrocanthosaurus atokensis and Strutiomimum sedens, and a near-complete skeleton of a sub-adult Edmontosaurus annectens. LiDAR scanning allows a full mounted skeleton to be imaged resulting in a detailed 3D model in which each bone retains its spatial position and articulation. This provides a high resolution skeletal framework around which the body cavity and internal organs such as lungs and air sacs can be reconstructed. This has allowed calculation of body segment masses, centres of mass and moments or inertia for each animal. However, any soft tissue reconstruction of an extinct taxon inevitably represents a best estimate model with an unknown level of accuracy. We have therefore conducted an extensive sensitivity analysis in which the volumes of body segments and respiratory organs were varied in an attempt to constrain the likely maximum plausible range of mass parameters for each animal. Our results provide wide ranges in actual mass and inertial values, emphasizing the high level of uncertainty inevitable in such reconstructions. However, our sensitivity analysis consistently places the centre of mass well below and in front of hip joint in each animal, regardless of the chosen combination of body and respiratory structure volumes. These results emphasize that future

  13. Estimating Mass Properties of Dinosaurs Using Laser Imaging and 3D Computer Modelling

    PubMed Central

    Bates, Karl T.; Manning, Phillip L.; Hodgetts, David; Sellers, William I.

    2009-01-01

    Body mass reconstructions of extinct vertebrates are most robust when complete to near-complete skeletons allow the reconstruction of either physical or digital models. Digital models are most efficient in terms of time and cost, and provide the facility to infinitely modify model properties non-destructively, such that sensitivity analyses can be conducted to quantify the effect of the many unknown parameters involved in reconstructions of extinct animals. In this study we use laser scanning (LiDAR) and computer modelling methods to create a range of 3D mass models of five specimens of non-avian dinosaur; two near-complete specimens of Tyrannosaurus rex, the most complete specimens of Acrocanthosaurus atokensis and Strutiomimum sedens, and a near-complete skeleton of a sub-adult Edmontosaurus annectens. LiDAR scanning allows a full mounted skeleton to be imaged resulting in a detailed 3D model in which each bone retains its spatial position and articulation. This provides a high resolution skeletal framework around which the body cavity and internal organs such as lungs and air sacs can be reconstructed. This has allowed calculation of body segment masses, centres of mass and moments or inertia for each animal. However, any soft tissue reconstruction of an extinct taxon inevitably represents a best estimate model with an unknown level of accuracy. We have therefore conducted an extensive sensitivity analysis in which the volumes of body segments and respiratory organs were varied in an attempt to constrain the likely maximum plausible range of mass parameters for each animal. Our results provide wide ranges in actual mass and inertial values, emphasizing the high level of uncertainty inevitable in such reconstructions. However, our sensitivity analysis consistently places the centre of mass well below and in front of hip joint in each animal, regardless of the chosen combination of body and respiratory structure volumes. These results emphasize that future

  14. Hyaluronic acid enhances the mechanical properties of tissue-engineered cartilage constructs.

    PubMed

    Levett, Peter A; Hutmacher, Dietmar W; Malda, Jos; Klein, Travis J

    2014-01-01

    There is a need for materials that are well suited for cartilage tissue engineering. Hydrogels have emerged as promising biomaterials for cartilage repair, since, like cartilage, they have high water content, and they allow cells to be encapsulated within the material in a genuinely three-dimensional microenvironment. In this study, we investigated the mechanical properties of tissue-engineered cartilage constructs using in vitro culture models incorporating human chondrocytes from osteoarthritis patients. We evaluated hydrogels formed from mixtures of photocrosslinkable gelatin-methacrylamide (Gel-MA) and varying concentrations (0-2%) of hyaluronic acid methacrylate (HA-MA). Initially, only small differences in the stiffness of each hydrogel existed. After 4 weeks of culture, and to a greater extent 8 weeks of culture, HA-MA had striking and concentration dependent impact on the changes in mechanical properties. For example, the initial compressive moduli of cell-laden constructs with 0 and 1% HA-MA were 29 and 41 kPa, respectively. After 8 weeks of culture, the moduli of these constructs had increased to 66 and 147 kPa respectively, representing a net improvement of 69 kPa for gels with 1% HA-MA. Similarly the equilibrium modulus, dynamic modulus, failure strength and failure strain were all improved in constructs containing HA-MA. Differences in mechanical properties did not correlate with glycosaminoglycan content, which did not vary greatly between groups, yet there were clear differences in aggrecan intensity and distribution as assessed using immunostaining. Based on the functional development with time in culture using human chondrocytes, mixtures of Gel-MA and HA-MA are promising candidates for cartilage tissue-engineering applications.

  15. Mass Properties Testing and Evaluation for the Multi-Mission Radioisotope Thermoelectric Generator

    SciTech Connect

    Felicione, Frank S.

    2009-12-01

    Mass properties (MP) measurements were performed for the Multi-Mission Radioisotope Thermoelectric Generator (MMRTG), serial number (S/N) 0X730401, the power system designated for the Mars Science Laboratory (MSL) mission. Measurements were made using new mounting fixtures at the mass properties testing station in the Idaho National Laboratory (INL) Space and Security Power Systems Facility (SSPSF). The objective of making mass properties measurements was to determine the generator’s flight configured mass and center of mass or center of gravity (CG). Using an extremely accurate platform scale, the mass of the as-tested generator was determined to be 100.117 ± 0.007 lb. Weight accuracy was determined by checking the platform scale with calibrated weights immediately prior to weighing the MMRTG.a CG measurement accuracy was assessed by surrogate testing using an inert mass standard for which the CG could be readily determined analytically. Repeated testing using the mass standard enabled the basic measurement precision of the system to be quantified in terms of a physical confidence interval about the measured CG position. However, repetitious testing with the MMRTG itself was not performed in deference to the gamma and neutron radiation dose to operators and the damage potential to the flight unit from extra handling operations. Since the mass standard had been specially designed to have a total weight and CG location that closely matched the MMRTG, the uncertainties determined from its testing were assigned to the MMRTG as well. On this basis, and at the 99% confidence level, a statistical analysis found the direct, as-measured MMRTG-MSL CG to be located at 10.816 ± 0.0011 in. measured perpendicular from the plane of the lower surface of the generator’s mounting lugs (Z direction), and offset from the generator’s long axis centerline in the X and Y directions by 0.0968 ± 0.0040 in. and 0.0276 ± 0.0026 in., respectively. These uncertainties are based

  16. Modulations of thermal properties of graphene by strain-induced phonon engineering

    NASA Astrophysics Data System (ADS)

    Tada, Kento; Funatani, Takashi; Konabe, Satoru; Sasaoka, Kenji; Ogawa, Matsuto; Souma, Satofumi; Yamamoto, Takahiro

    2017-02-01

    Modulation of the thermal properties of graphene due to strain-induced phononic band engineering was theoretically investigated by first-principles calculations based on the density functional theory. The high-energy phonon modes are found to exhibit softening owing to the strain, whereas a low-energy acoustic mode (out-of-plane mode) exhibits hardening. Moreover, the dispersion relation of the out-of-plane mode associated with the strain essentially changes from quadratic (∝ k 2) to linear (∝ k). Accordingly, the temperature dependence of the low-temperature specific heat also changes from linear (∝ T) to quadratic (∝ T 2).

  17. Controlling thermal and electrical properties of graphene by strain-engineering its flexural phonons

    NASA Astrophysics Data System (ADS)

    Conley, Hiram; Nicholl, Ryan; Bolotin, Kirill

    2014-03-01

    We explore the effects of flexural phonons on the thermal and electrical properties of graphene. To control the amplitude of flexural phonons, we developed a technique to engineer uniform mechanical strain between 0 and 1% in suspended graphene. We determine the level of strain, thermal conductivity and carrier mobility of graphene through a combination of mechanical resonance and electrical transport measurements. Depending on strain, we find significant changes in the thermal expansion coefficient, thermal conductivity, and carrier mobility of suspended graphene. These changes are consistent with the expected contribution of flexural phonons.

  18. Fuel property effects on fuel/air mixing in an experimental diesel engine

    SciTech Connect

    Browne, K.R.; Patridge, I.M.; Greeves, G.

    1986-01-01

    Fuels of widely varying properties are studied by injection of a single and well defined spray into an experimental diesel engine. Three optical techniques were developed to visualise liquid fuel, fuel vapour, flame, soot and individual droplets and their associated vapour trails. Liquid core length measurements are presented for diesel fuel, toluene, ethanol and sunflower oil. Computer model predictions show that an increase of the fuel mid-boiling point by 40/sup 0/C gives a similar effect on liquid core length to an increase of 0.03mm in the nozzle hole diameter.

  19. CMC Property Variability and Life Prediction Methods for Turbine Engine Component Application

    NASA Technical Reports Server (NTRS)

    Cheplak, Matthew L.

    2004-01-01

    The ever increasing need for lower density and higher temperature-capable materials for aircraft engines has led to the development of Ceramic Matrix Composites (CMCs). Today's aircraft engines operate with >3000"F gas temperatures at the entrance to the turbine section, but unless heavily cooled, metallic components cannot operate above approx.2000 F. CMCs attempt to push component capability to nearly 2700 F with much less cooling, which can help improve engine efficiency and performance in terms of better fuel efficiency, higher thrust, and reduced emissions. The NASA Glenn Research Center has been researching the benefits of the SiC/SiC CMC for engine applications. A CMC is made up of a matrix material, fibers, and an interphase, which is a protective coating over the fibers. There are several methods or architectures in which the orientation of the fibers can be manipulated to achieve a particular material property objective as well as a particular component geometric shape and size. The required shape manipulation can be a limiting factor in the design and performance of the component if there is a lack of bending capability of the fiber as making the fiber more flexible typically sacrifices strength and other fiber properties. Various analysis codes are available (pcGINA, CEMCAN) that can predict the effective Young's Moduli, thermal conductivities, coefficients of thermal expansion (CTE), and various other properties of a CMC. There are also various analysis codes (NASAlife) that can be used to predict the life of CMCs under expected engine service conditions. The objective of this summer study is to utilize and optimize these codes for examining the tradeoffs between CMC properties and the complex fiber architectures that will be needed for several different component designs. For example, for the pcGINA code, there are six variations of architecture available. Depending on which architecture is analyzed, the user is able to specify the fiber tow size, tow

  20. Physical properties of the human head: mass, center of gravity and moment of inertia.

    PubMed

    Yoganandan, Narayan; Pintar, Frank A; Zhang, Jiangyue; Baisden, Jamie L

    2009-06-19

    This paper presents a synthesis of biomedical investigations of the human head with specific reference to certain aspects of physical properties and development of anthropometry data, leading to the advancement of dummies used in crashworthiness research. As a significant majority of the studies have been summarized as reports, an effort has been made to chronologically review the literature with the above objectives. The first part is devoted to early studies wherein the mass, center of gravity (CG), and moment of inertia (MOI) properties are obtained from human cadaver experiments. Unembalmed and preserved whole-body and isolated head and head-neck experiments are discussed. Acknowledging that the current version of the Hybrid III dummy is the most widely used anthropomorphic test device in motor vehicle crashworthiness research for frontal impact applications for over 30 years, bases for the mass and MOI-related data used in the dummy are discussed. Since the development and federalization of the dummy in the United States, description of methods used to arrive at these properties form a part of the manuscript. Studies subsequent to the development of this dummy including those from the US Military are also discussed. As the head and neck are coupled in any impact, and increasing improvements in technology such as advanced airbags, and pre-tensioners and load limiters in manual seatbelts affect the kinetics of the head-neck complex, the manuscript underscores the need to pursue studies to precisely determine all the physical properties of the head. Because the most critical parameters (locations of CG and occipital condyles (OC), mass, and MOI) have not been determined on a specimen-by-specimen basis in any single study, it is important to gather these data in future experiments. These critical data will be of value for improving occupant safety, designing advanced restraint systems, developing second generation dummies, and assessing the injury mitigating

  1. Crescendo: A Protein Sequence Database Search Engine for Tandem Mass Spectra

    NASA Astrophysics Data System (ADS)

    Wang, Jianqi; Zhang, Yajie; Yu, Yonghao

    2015-07-01

    A search engine that discovers more peptides reliably is essential to the progress of the computational proteomics. We propose two new scoring functions (L- and P-scores), which aim to capture similar characteristics of a peptide-spectrum match (PSM) as Sequest and Comet do. Crescendo, introduced here, is a software program that implements these two scores for peptide identification. We applied Crescendo to test datasets and compared its performance with widely used search engines, including Mascot, Sequest, and Comet. The results indicate that Crescendo identifies a similar or larger number of peptides at various predefined false discovery rates (FDR). Importantly, it also provides a better separation between the true and decoy PSMs, warranting the future development of a companion post-processing filtering algorithm.

  2. Crescendo: A Protein Sequence Database Search Engine for Tandem Mass Spectra.

    PubMed

    Wang, Jianqi; Zhang, Yajie; Yu, Yonghao

    2015-07-01

    A search engine that discovers more peptides reliably is essential to the progress of the computational proteomics. We propose two new scoring functions (L- and P-scores), which aim to capture similar characteristics of a peptide-spectrum match (PSM) as Sequest and Comet do. Crescendo, introduced here, is a software program that implements these two scores for peptide identification. We applied Crescendo to test datasets and compared its performance with widely used search engines, including Mascot, Sequest, and Comet. The results indicate that Crescendo identifies a similar or larger number of peptides at various predefined false discovery rates (FDR). Importantly, it also provides a better separation between the true and decoy PSMs, warranting the future development of a companion post-processing filtering algorithm.

  3. Origin of Disagreements in Tandem Mass Spectra Interpretation by Search Engines.

    PubMed

    Tessier, Dominique; Lollier, Virginie; Larré, Colette; Rogniaux, Hélène

    2016-10-07

    Several proteomic database search engines that interpret LC-MS/MS data do not identify the same set of peptides. These disagreements occur even when the scores of the peptide-to-spectrum matches suggest good confidence in the interpretation. Our study shows that these disagreements observed for the interpretations of a given spectrum are almost exclusively due to the variation of what we call the "peptide space", i.e., the set of peptides that are actually compared to the experimental spectra. We discuss the potential difficulties of precisely defining the "peptide space." Indeed, although several parameters that are generally reported in publications can easily be set to the same values, many additional parameters-with much less straightforward user access-might impact the "peptide space" used by each program. Moreover, in a configuration where each search engine identifies the same candidates for each spectrum, the inference of the proteins may remain quite different depending on the false discovery rate selected.

  4. The Transport of Mass, Energy, and Entropy in Cryogenic Support Struts for Engineering Design

    NASA Technical Reports Server (NTRS)

    Elchert, J. P.

    2012-01-01

    Engineers working to understand and reduce cryogenic boil-off must solve a. variety of transport problems. An important class of nonlinear problems involves the thermal and mechanical design of cryogenic struts. These classic problems are scattered about the literature and typically require too many resources to obtain. So, to save time for practicing engineers, the author presents this essay. Herein, a variety of new, old, and revisited analytical and finite difference solutions of the thermal problem are covered in this essay, along with commentary on approach and assumptions, This includes a few thermal radiation and conduction combined mode solution with a discussion on insulation, optimum emissivity, and geometrical phenomenon. Solutions to cooling and heat interception problems are also presented, including a discussion of the entropy generation. And the literature on the combined mechanical and thermal design of cryogenic support struts is reviewed with an introduction to the associated numerical methods.

  5. The Transport of Mass, Energy, and Entropy in Cryogenic Support Struts for Engineering Design

    NASA Technical Reports Server (NTRS)

    Elchert, J. P.

    2012-01-01

    Engineers working to understand and reduce cryogenic boil-off must solve a variety of transport problems. An important class of nonlinear problems involves the thermal and mechanical design of cryogenic struts. These classic problems are scattered about the literature and typically require too many resources to obtain. So, to save time for practicing engineers, the author presents this essay. Herein, a variety of new, old, and revisited analytical and finite difference solutions of the thermal problem are covered in this essay, along with commentary on approach and assumptions. This includes a few thermal radiation and conduction combined mode solutions with a discussion on insulation, optimum emissivity, and geometrical phenomenon. Solutions to cooling and heat interception problems are also presented, including a discussion of the entropy generation. The literature on the combined mechanical and thermal design of cryogenic support struts is reviewed with an introduction to the associated numerical methods.

  6. Computational fluid dynamics modeling of steady-state momentum and mass transport in a bioreactor for cartilage tissue engineering.

    PubMed

    Williams, Kenneth A; Saini, Sunil; Wick, Timothy M

    2002-01-01

    Computational fluid dynamics (CFD) models to quantify momentum and mass transport under conditions of tissue growth will aid bioreactor design for development of tissue-engineered cartilage constructs. Fluent CFD models are used to calculate flow fields, shear stresses, and oxygen profiles around nonporous constructs simulating cartilage development in our concentric cylinder bioreactor. The shear stress distribution ranges from 1.5 to 12 dyn/cm(2) across the construct surfaces exposed to fluid flow and varies little with the relative number or placement of constructs in the bioreactor. Approximately 80% of the construct surface exposed to flow experiences shear stresses between 1.5 and 4 dyn/cm(2), validating the assumption that the concentric cylinder bioreactor provides a relatively homogeneous hydrodynamic environment for construct growth. Species mass transport modeling for oxygen demonstrates that fluid-phase oxygen transport to constructs is uniform. Some O(2) depletion near the down stream edge of constructs is noted with minimum pO(2) values near the constructs of 35 mmHg (23% O(2) saturation). These values are above oxygen concentrations in cartilage in vivo, suggesting that bioreactor oxygen concentrations likely do not affect chondrocyte growth. Scale-up studies demonstrate the utility and flexibility of CFD models to design and characterize bioreactors for growth of tissue-engineered cartilage.

  7. Optimization of System Maturity and Equivalent System Mass for Space Systems Engineering Management

    DTIC Science & Technology

    2010-03-01

    compatibility in a manner that optimizes the total system definition and design [12]. From a systems engineering management perspective, it becomes...Department of Defense, US Department of Energy, and United Kingdom Ministry of Defence). However, TRL, by definition , can only refer to the maturity...purpose of supplying food and revitalizing air. Waste Processing: technology functions include water/resource recovery, safening and stabilization

  8. Molecularly imprinted sol-gel nanoparticles for mass-sensitive engine oil degradation sensing.

    PubMed

    Lieberzeit, Peter A; Afzal, Adeel; Glanzing, Gerd; Dickert, Franz L

    2007-09-01

    Titanate sol-gel layers imprinted with midchain carbonic acids have proven highly useful for detecting engine oil degradation processes owing to selective incorporation of oxidised base oil components. Synthesising the material from TiCl(4) in CCl(4) and precipitating with water leads to imprinted TiO(2) nanoparticles with a diameter of 200-300 nm. Replacing the water by a 1 M ammonium hydroxide solution reduces the average particle size to 50-100 nm with retention of the interaction capabilities. Experiments with the latter solution revealed that the 100-nm particles take up substantially more analyte, indicating a size-dependent phenomenon. As the number of interaction sites within each material is the same, this cannot be a consequence of thermodynamics but must be one of accessibility. The sensor characteristic of water-precipitated particles towards engine oil degradation products shows substantially increased sensitivity and dynamic range compared with the corresponding thin films. Coating quartz crystal microbalances with such nanoparticle materials leads to engine oil degradation sensors owing to incorporation of acidic base oil oxidation products. Interaction studies over a large range of layer thicknesses revealed that both the absolute signal and the steepness of the correlation between the sensor signal and the layer height is 2 times higher for the particles.

  9. FDRAnalysis: A tool for the integrated analysis of tandem mass spectrometry identification results from multiple search engines

    PubMed Central

    Wedge, David C; Krishna, Ritesh; Blackhurst, Paul; Siepen, Jennifer A; Jones, Andrew R.; Hubbard, Simon J.

    2013-01-01

    Confident identification of peptides via tandem mass spectrometry underpins modern high-throughput proteomics. This has motivated considerable recent interest in the post-processing of search engine results to increase confidence and calculate robust statistical measures, for example through the use of decoy databases to calculate false discovery rates (FDR). FDR-based analyses allow for multiple testing and can assign a single confidence value for both sets and individual peptide spectrum matches (PSMs). We recently developed an algorithm for combining the results from multiple search engines, integrating FDRs for sets of PSMs made by different search engine combinations. Here we describe a web-server, and a downloadable application, which makes this routinely available to the proteomics community. The web server offers a range of outputs including informative graphics to assess the confidence of the PSMs and any potential biases. The underlying pipeline provides a basic protein inference step, integrating PSMs into protein ambiguity groups where peptides can be matched to more than one protein. Importantly, we have also implemented full support for the mzIdentML data standard, recently released by the Proteomics Standards Initiative, providing users with the ability to convert native formats to mzIdentML files, which are available to download. PMID:21222473

  10. FDRAnalysis: a tool for the integrated analysis of tandem mass spectrometry identification results from multiple search engines.

    PubMed

    Wedge, David C; Krishna, Ritesh; Blackhurst, Paul; Siepen, Jennifer A; Jones, Andrew R; Hubbard, Simon J

    2011-04-01

    Confident identification of peptides via tandem mass spectrometry underpins modern high-throughput proteomics. This has motivated considerable recent interest in the postprocessing of search engine results to increase confidence and calculate robust statistical measures, for example through the use of decoy databases to calculate false discovery rates (FDR). FDR-based analyses allow for multiple testing and can assign a single confidence value for both sets and individual peptide spectrum matches (PSMs). We recently developed an algorithm for combining the results from multiple search engines, integrating FDRs for sets of PSMs made by different search engine combinations. Here we describe a web-server and a downloadable application that makes this routinely available to the proteomics community. The web server offers a range of outputs including informative graphics to assess the confidence of the PSMs and any potential biases. The underlying pipeline also provides a basic protein inference step, integrating PSMs into protein ambiguity groups where peptides can be matched to more than one protein. Importantly, we have also implemented full support for the mzIdentML data standard, recently released by the Proteomics Standards Initiative, providing users with the ability to convert native formats to mzIdentML files, which are available to download.

  11. The seismic properties of low-mass He-core white dwarf stars

    NASA Astrophysics Data System (ADS)

    Córsico, A. H.; Romero, A. D.; Althaus, L. G.; Hermes, J. J.

    2012-11-01

    Context. In recent years, many low-mass (≲ 0.45 M⊙) white dwarf stars expected to harbor He cores have been detected in the field of the Milky Way and in several galactic globular and open clusters. Until recently, no objects of this kind showed pulsations. This situation has changed recently with the exciting discovery of SDSS J184037.78+642312.3, the first pulsating low-mass white dwarf star. Aims: Motivated by this extremely important finding, and in view of the very valuable asteroseismological potential of these objects, we present here a detailed pulsational study applied to low-mass He-core white dwarfs with masses ranging from 0.17 to 0.46 M⊙, based on full evolutionary models representative of these objects. This study is aimed to provide a theoretical basis from which to interpret future observations of variable low-mass white dwarfs. Methods: The background stellar models on which our pulsational analysis was carried out were derived by taking into account the complete evolutionary history of the progenitor stars, with special emphasis on the diffusion processes acting during the white dwarf cooling phase. We computed nonradial g-modes to assess the dependence of the pulsational properties of these objects with stellar parameters such as the stellar mass and the effective temperature, and also with element diffusion processes. We also performed a g- and p-mode pulsational stability analysis on our models and found well-defined blue edges of the instability domain, where these stars should start to exhibit pulsations. Results: We found substantial differences in the seismic properties of white dwarfs with M∗ ≳ 0.20 M⊙ and the extremely low-mass (ELM) white dwarfs (M∗ ≲ 0.20 M⊙). Specifically, g-mode pulsation modes in ELM white dwarfs mainly probe the core regions and are not dramatically affected by mode-trapping effects by the He/H interface, whereas the opposite is true for more massive He-core white dwarfs. We found that element

  12. Replication of engine block cylinder bridge microstructure and mechanical properties with lab scale 319 Al alloy billet castings

    SciTech Connect

    Lombardi, A.; D'Elia, F.; Ravindran, C.; MacKay, R.

    2014-01-15

    In recent years, aluminum alloy gasoline engine blocks have in large part successfully replaced nodular cast iron engine blocks, resulting in improved vehicle fuel efficiency. However, because of the inadequate wear resistance properties of hypoeutectic Al–Si alloys, gray iron cylinder liners are required. These liners cause the development of large tensile residual stress along the cylinder bores and necessitate the maximization of mechanical properties in this region to prevent premature engine failure. The aim of this study was to replicate the engine cylinder bridge microstructure and mechanical properties following TSR treatment (which removes the sand binder to enable easy casting retrieval) using lab scale billet castings of the same alloy composition with varying cooling rates. Comparisons in microstructure between the engine block and the billet castings were carried out using optical and scanning electron microscopy, while mechanical properties were assessed using tensile testing. The results suggest that the microstructure at the top and middle of the engine block cylinder bridge was successfully replicated by the billet castings. However, the microstructure at the bottom of the cylinder was not completely replicated due to variations in secondary phase morphology and distribution. The successful replication of engine block microstructure will enable the future optimization of heat treatment parameters. - Highlights: • A method to replicate engine block microstructure was developed. • Billet castings will allow cost effective optimization of heat treatment process. • The replication of microstructure in the cylinder region was mostly successful. • Porosity was more clustered in the billet castings compared to the engine block. • Mechanical properties were lower in billet castings due to porosity and inclusions.

  13. Grain Boundary Engineering the Mechanical Properties of Allvac 718Plus(Trademark) Superalloy

    NASA Technical Reports Server (NTRS)

    Gabb, Timothy P.; Telesman, Jack; Garg, Anita; Lin, Peter; Provenzano, virgil; Heard, Robert; Miller, Herbert M.

    2010-01-01

    Grain Boundary Engineering can enhance the population of structurally-ordered "low S" Coincidence Site Lattice (CSL) grain boundaries in the microstructure. In some alloys, these "special" grain boundaries have been reported to improve overall resistance to corrosion, oxidation, and creep resistance. Such improvements could be quite beneficial for superalloys, especially in conditions which encourage damage and cracking at grain boundaries. Therefore, the effects of GBE processing on high-temperature mechanical properties of the cast and wrought superalloy Allvac 718Plus (Allvac ATI) were screened. Bar sections were subjected to varied GBE processing, and then consistently heat treated, machined, and tested at 650 C. Creep, tensile stress relaxation, and dwell fatigue crack growth tests were performed. The influences of GBE processing on microstructure, mechanical properties, and associated failure modes are discussed.

  14. Geoenvironmental and engineering properties of rock, soil, and aggregate. Transportation research record

    SciTech Connect

    Not Available

    1992-01-01

    Partial Contents: Use of Waste Materials in Highway Construction: State of the Practice and Evaluation of the Selected Waste Products; Physical and Environmental Properties of Asphalt-Amended Bottom Ash; Use of Cement Kiln Dust, Fly Ash, and Recycling Technique in Low-Volume Road Rehabilitation; Use of By-Product Phosphogypsum in Road Construction; Stabilization of Water Treatment Plant Sludge for Possible Use as Embankment Material; Construction and Performance of a Shredded Waste Tire Test Embankment; Corrosion of Steel Piles in Some Waste Fills; Recycled Plastics for Highway Agencies; Effect of Chloride and Sulfate Contamination in Soils on Corrosion of Steel and Concrete; Permeability and Leaching Characteristics of Fly Ash Liner Materials; Evaluation of Recycled Concrete, Open-Graded Aggregate, and Large Top-Size Aggregate Bases; Engineering Properties of Phosphogypsum-Based Slag Aggregate.

  15. Diesel Surrogate Fuels for Engine Testing and Chemical-Kinetic Modeling: Compositions and Properties.

    PubMed

    Mueller, Charles J; Cannella, William J; Bays, J Timothy; Bruno, Thomas J; DeFabio, Kathy; Dettman, Heather D; Gieleciak, Rafal M; Huber, Marcia L; Kweon, Chol-Bum; McConnell, Steven S; Pitz, William J; Ratcliff, Matthew A

    2016-02-18

    The primary objectives of this work were to formulate, blend, and characterize a set of four ultralow-sulfur diesel surrogate fuels in quantities sufficient to enable their study in single-cylinder-engine and combustion-vessel experiments. The surrogate fuels feature increasing levels of compositional accuracy (i.e., increasing exactness in matching hydrocarbon structural characteristics) relative to the single target diesel fuel upon which the surrogate fuels are based. This approach was taken to assist in determining the minimum level of surrogate-fuel compositional accuracy that is required to adequately emulate the performance characteristics of the target fuel under different combustion modes. For each of the four surrogate fuels, an approximately 30 L batch was blended, and a number of the physical and chemical properties were measured. This work documents the surrogate-fuel creation process and the results of the property measurements.

  16. Diesel Surrogate Fuels for Engine Testing and Chemical-Kinetic Modeling: Compositions and Properties

    PubMed Central

    Mueller, Charles J.; Cannella, William J.; Bays, J. Timothy; Bruno, Thomas J.; DeFabio, Kathy; Dettman, Heather D.; Gieleciak, Rafal M.; Huber, Marcia L.; Kweon, Chol-Bum; McConnell, Steven S.; Pitz, William J.; Ratcliff, Matthew A.

    2016-01-01

    The primary objectives of this work were to formulate, blend, and characterize a set of four ultralow-sulfur diesel surrogate fuels in quantities sufficient to enable their study in single-cylinder-engine and combustion-vessel experiments. The surrogate fuels feature increasing levels of compositional accuracy (i.e., increasing exactness in matching hydrocarbon structural characteristics) relative to the single target diesel fuel upon which the surrogate fuels are based. This approach was taken to assist in determining the minimum level of surrogate-fuel compositional accuracy that is required to adequately emulate the performance characteristics of the target fuel under different combustion modes. For each of the four surrogate fuels, an approximately 30 L batch was blended, and a number of the physical and chemical properties were measured. This work documents the surrogate-fuel creation process and the results of the property measurements. PMID:27330248

  17. PGS:Gelatin Nanofibrous Scaffolds with Tunable Mechanical and Structural Properties for Engineering Cardiac Tissues

    PubMed Central

    Kharaziha, Mahshid; Nikkhah, Mehdi; Shin, Su-Ryon; Annabi, Nasim; Masoumi, Nafiseh; Gaharwar, Akhilesh K.; Camci-Unal, Gulden; Khademhosseini, Ali

    2013-01-01

    A significant challenge in cardiac tissue engineering is the development of biomimetic grafts that can potentially promote myocardial repair and regeneration. A number of approaches have used engineered scaffolds to mimic the architecture of the native myocardium tissue and precisely regulate cardiac cell functions. However previous attempts have not been able to simultaneously recapitulate chemical, mechanical, and structural properties of the myocardial extracellular matrix (ECM). In this study, we utilized an electrospinning approach to fabricate elastomeric biodegradable poly(glycerol-sebacate) (PGS):gelatin scaffolds with a wide range of chemical composition, stiffness and anisotropy. Our findings demonstrated that through incorporation of PGS, it is possible to create nanofibrous scaffolds with well-defined anisotropy that mimics the left ventricular myocardium architecture. Furthermore, we studied attachment, proliferation, differentiation and alignment of neonatal rat cardiac fibroblast cells (CFs) as well as protein expression, alignment, and contractile function of cardiomyocyte (CMs) on PGS:gelatin scaffolds with variable amount of PGS. Notably, aligned nanofibrous scaffold, consisting of 33 wt. % PGS, induced optimal synchronous contractions of CMs while significantly enhanced cellular alignment. Overall, our study suggests that the aligned nanofibrous PGS:gelatin scaffold support cardiac cell organization, phenotype and contraction and could potentially be used to develop clinically relevant constructs for cardiac tissue engineering. PMID:23747008

  18. PGS:Gelatin nanofibrous scaffolds with tunable mechanical and structural properties for engineering cardiac tissues.

    PubMed

    Kharaziha, Mahshid; Nikkhah, Mehdi; Shin, Su-Ryon; Annabi, Nasim; Masoumi, Nafiseh; Gaharwar, Akhilesh K; Camci-Unal, Gulden; Khademhosseini, Ali

    2013-09-01

    A significant challenge in cardiac tissue engineering is the development of biomimetic grafts that can potentially promote myocardial repair and regeneration. A number of approaches have used engineered scaffolds to mimic the architecture of the native myocardium tissue and precisely regulate cardiac cell functions. However, previous attempts have not been able to simultaneously recapitulate chemical, mechanical, and structural properties of the myocardial extracellular matrix (ECM). In this study, we utilized an electrospinning approach to fabricate elastomeric biodegradable poly(glycerol sebacate) (PGS):gelatin nanofibrous scaffolds with a wide range of chemical composition, stiffness and anisotropy. Our findings demonstrated that through incorporation of PGS, it is possible to create nanofibrous scaffolds with well-defined anisotropy that mimic the left ventricular myocardium architecture. Furthermore, we studied attachment, proliferation, differentiation and alignment of neonatal rat cardiac fibroblast cells (CFs) as well as protein expression, alignment, and contractile function of cardiomyocyte (CMs) on PGS:gelatin scaffolds with variable amount of PGS. Notably, aligned nanofibrous scaffold, consisting of 33 wt. % PGS, induced optimal synchronous contractions of CMs while significantly enhanced cellular alignment. Overall, our study suggests that the aligned nanofibrous PGS:gelatin scaffold support cardiac cell organization, phenotype and contraction and could potentially be used to develop clinically relevant constructs for cardiac tissue engineering.

  19. Effective-mass model and magneto-optical properties in hybrid perovskites

    PubMed Central

    Yu, Z. G.

    2016-01-01

    Hybrid inorganic-organic perovskites have proven to be a revolutionary material for low-cost photovoltaic applications. They also exhibit many other interesting properties, including giant Rashba splitting, large-radius Wannier excitons, and novel magneto-optical effects. Understanding these properties as well as the detailed mechanism of photovoltaics requires a reliable and accessible electronic structure, on which models of transport, excitonic, and magneto-optical properties can be efficiently developed. Here we construct an effective-mass model for the hybrid perovskites based on the group theory, experiment, and first-principles calculations. Using this model, we relate the Rashba splitting with the inversion-asymmetry parameter in the tetragonal perovskites, evaluate anisotropic g-factors for both conduction and valence bands, and elucidate the magnetic-field effect on photoluminescence and its dependence on the intensity of photoexcitation. The diamagnetic effect of exciton is calculated for an arbitrarily strong magnetic field. The pronounced excitonic peak emerged at intermediate magnetic fields in cyclotron resonance is assigned to the 3D±2 states, whose splitting can be used to estimate the difference in the effective masses of electron and hole. PMID:27338834

  20. Reconnection Properties of Large-scale Current Sheets During Coronal Mass Ejection Eruptions

    NASA Astrophysics Data System (ADS)

    Lynch, B. J.; Edmondson, J. K.; Kazachenko, M. D.; Guidoni, S. E.

    2016-07-01

    We present a detailed analysis of the properties of magnetic reconnection at large-scale current sheets (CSs) in a high cadence version of the Lynch & Edmondson 2.5D MHD simulation of sympathetic magnetic breakout eruptions from a pseudostreamer source region. We examine the resistive tearing and break-up of the three main CSs into chains of X- and O-type null points and follow the dynamics of magnetic island growth, their merging, transit, and ejection with the reconnection exhaust. For each CS, we quantify the evolution of the length-to-width aspect ratio (up to ˜100:1), Lundquist number (˜103), and reconnection rate (inflow-to-outflow ratios reaching ˜0.40). We examine the statistical and spectral properties of the fluctuations in the CSs resulting from the plasmoid instability, including the distribution of magnetic island area, mass, and flux content. We show that the temporal evolution of the spectral index of the reconnection-generated magnetic energy density fluctuations appear to reflect global properties of the CS evolution. Our results are in excellent agreement with recent, high-resolution reconnection-in-a-box simulations even though our CSs’ formation, growth, and dynamics are intrinsically coupled to the global evolution of sequential sympathetic coronal mass ejection eruptions.

  1. Effective-mass model and magneto-optical properties in hybrid perovskites

    NASA Astrophysics Data System (ADS)

    Yu, Z. G.

    2016-06-01

    Hybrid inorganic-organic perovskites have proven to be a revolutionary material for low-cost photovoltaic applications. They also exhibit many other interesting properties, including giant Rashba splitting, large-radius Wannier excitons, and novel magneto-optical effects. Understanding these properties as well as the detailed mechanism of photovoltaics requires a reliable and accessible electronic structure, on which models of transport, excitonic, and magneto-optical properties can be efficiently developed. Here we construct an effective-mass model for the hybrid perovskites based on the group theory, experiment, and first-principles calculations. Using this model, we relate the Rashba splitting with the inversion-asymmetry parameter in the tetragonal perovskites, evaluate anisotropic g-factors for both conduction and valence bands, and elucidate the magnetic-field effect on photoluminescence and its dependence on the intensity of photoexcitation. The diamagnetic effect of exciton is calculated for an arbitrarily strong magnetic field. The pronounced excitonic peak emerged at intermediate magnetic fields in cyclotron resonance is assigned to the 3D±2 states, whose splitting can be used to estimate the difference in the effective masses of electron and hole.

  2. Effective-mass model and magneto-optical properties in hybrid perovskites.

    PubMed

    Yu, Z G

    2016-06-24

    Hybrid inorganic-organic perovskites have proven to be a revolutionary material for low-cost photovoltaic applications. They also exhibit many other interesting properties, including giant Rashba splitting, large-radius Wannier excitons, and novel magneto-optical effects. Understanding these properties as well as the detailed mechanism of photovoltaics requires a reliable and accessible electronic structure, on which models of transport, excitonic, and magneto-optical properties can be efficiently developed. Here we construct an effective-mass model for the hybrid perovskites based on the group theory, experiment, and first-principles calculations. Using this model, we relate the Rashba splitting with the inversion-asymmetry parameter in the tetragonal perovskites, evaluate anisotropic g-factors for both conduction and valence bands, and elucidate the magnetic-field effect on photoluminescence and its dependence on the intensity of photoexcitation. The diamagnetic effect of exciton is calculated for an arbitrarily strong magnetic field. The pronounced excitonic peak emerged at intermediate magnetic fields in cyclotron resonance is assigned to the 3D±2 states, whose splitting can be used to estimate the difference in the effective masses of electron and hole.

  3. High seeding density of human chondrocytes in agarose produces tissue-engineered cartilage approaching native mechanical and biochemical properties.

    PubMed

    Cigan, Alexander D; Roach, Brendan L; Nims, Robert J; Tan, Andrea R; Albro, Michael B; Stoker, Aaron M; Cook, James L; Vunjak-Novakovic, Gordana; Hung, Clark T; Ateshian, Gerard A

    2016-06-14

    Animal cells have served as highly controllable model systems for furthering cartilage tissue engineering practices in pursuit of treating osteoarthritis. Although successful strategies for animal cells must ultimately be adapted to human cells to be clinically relevant, human chondrocytes are rarely employed in such studies. In this study, we evaluated the applicability of culture techniques established for juvenile bovine and adult canine chondrocytes to human chondrocytes obtained from fresh or expired osteochondral allografts. Human chondrocytes were expanded and encapsulated in 2% agarose scaffolds measuring ∅3-4mm×2.3mm, with cell seeding densities ranging from 15 to 90×10(6)cells/mL. Subsets of constructs were subjected to transient or sustained TGF-β treatment, or provided channels to enhance nutrient transport. Human cartilaginous constructs physically resembled native human cartilage, and reached compressive Young's moduli of up to ~250kPa (corresponding to the low end of ranges reported for native knee cartilage), dynamic moduli of ~950kPa (0.01Hz), and contained 5.7% wet weight (%/ww) of glycosaminoglycans (≥ native levels) and 1.5%/ww collagen. We found that the initial seeding density had pronounced effects on tissue outcomes, with high cell seeding densities significantly increasing nearly all measured properties. Transient TGF-β treatment was ineffective for adult human cells, and tissue construct properties plateaued or declined beyond 28 days of culture. Finally, nutrient channels improved construct mechanical properties, presumably due to enhanced rates of mass transport. These results demonstrate that our previously established culture system can be successfully translated to human chondrocytes.

  4. Effects of Mass Fluctuation on Thermal Transport Properties in Bulk Bi2Te3

    NASA Astrophysics Data System (ADS)

    Huang, Ben; Zhai, Pengcheng; Yang, Xuqiu; Li, Guodong

    2016-10-01

    In this paper, we applied large-scale molecular dynamics and lattice dynamics to study the influence of mass fluctuation on thermal transport properties in bulk Bi2Te3, namely thermal conductivity (K), phonon density of state (PDOS), group velocity (v g), and mean free path (l). The results show that total atomic mass change can affect the relevant vibrational frequency on the micro level and heat transfer rate in the macro statistic, hence leading to the strength variation of the anharmonic phonon processes (Umklapp scattering) in the defect-free Bi2Te3 bulk. Moreover, it is interesting to find that the anharmonicity of Bi2Te3 can be also influenced by atomic differences of the structure such as the mass distribution in the primitive cell. Considering the asymmetry of the crystal structure and interatomic forces, it can be concluded by phonon frequency, lifetime, and velocity calculation that acoustic-optical phonon scattering shows the structure-sensitivity to the mass distribution and complicates the heat transfer mechanism, hence resulting in the low lattice thermal conductivity of Bi2Te3. This study is helpful for designing the material with tailored thermal conductivity via atomic substitution.

  5. Dielectric Characteristics of Microstructural Changes and Property Evolution in Engineered Materials

    NASA Astrophysics Data System (ADS)

    Clifford, Jallisa Janet

    Heterogeneous materials are increasingly used in a wide range of applications such as aerospace, civil infrastructure, fuel cells and many others. The ability to take properties from two or more materials to create a material with properties engineered to needs is always very attractive. Hence heterogeneous materials are evolving into more complex formulations in multiple disciplines. Design of microstructure at multiple scales control the global functional properties of these materials and their structures. However, local microstructural changes do not directly cause a proportional change to the global properties (such as strength and stiffness). Instead, local changes follow an evolution process including significant interactions. Therefore, in order to understand property evolution of engineered materials, microstructural changes need to be effectively captured. Characterizing these changes and representing them by material variables will enable us to further improve our material level understanding. In this work, we will demonstrate how microstructural features of heterogeneous materials can be described quantitatively using broadband dielectric spectroscopy (BbDS). The frequency dependent dielectric properties can capture the change in material microstructure and represent these changes in terms of material variables, such as complex permittivity. These changes in terms of material properties can then be linked to a number of different conditions, such as increasing damage due to impact or fatigue. Two different broadband dielectric spectroscopy scanning modes are presented: bulk measurements and continuous scanning to measure dielectric property change as a function of position across the specimen. In this study, we will focus on ceramic materials and fiber reinforced polymer matrix composites as test bed material systems. In the first part of the thesis, we will present how different micro-structural design of porous ceramic materials can be captured

  6. Mass spectrum and decay properties of heavy-light mesons: D, Ds, B and Bs mesons

    NASA Astrophysics Data System (ADS)

    Yazarloo, B. H.; Mehraban, H.

    2017-02-01

    We present a study of mass spectrum and decay properties of heavy-light mesons in the non-relativistic potential model. We consider a new type of potential for the mesonic system, the combination of harmonic and Yukawa-type potentials. To obtain the wave function of the system, we use the perturbation method. We take the harmonic term as parent and the Yukawa term as perturbation for the generation of wave function for the meson. For calculating the parent wave function, the Nikiforov-Uvarov (NU) approach is used and thereby we obtained a series solution for the perturbative wave function and then reported the total wave function. With this wave function, we then study the mass spectrum, the decay constant, the leptonic and semileptonic decay widths of heavy-light mesons.

  7. Analytical and experimental evaluations of the effect of broad property fuels on combustors for commercial aircraft gas turbine engines

    NASA Technical Reports Server (NTRS)

    Smith, A. L.

    1980-01-01

    The impacts of broad property fuels on the design, performance, durability, emissions, and operational characteristics of current and advanced combustors for commercial aircraft gas turbine engines were studied. The effect of fuel thermal stability on engine and airframe fuel system was evaluated. Tradeoffs between fuel properties, exhaust emissions, and combustor life were also investigated. Results indicate major impacts of broad property fuels on allowable metal temperatures in fuel manifolds and injector support, combustor cyclic durability, and somewhat lesser impacts on starting characteristics, lightoff, emissions, and smoke.

  8. Mathematical Modeling of Uniaxial Mechanical Properties of Collagen Gel Scaffolds for Vascular Tissue Engineering

    PubMed Central

    Irastorza, Ramiro M.; Drouin, Bernard; Blangino, Eugenia; Mantovani, Diego

    2015-01-01

    Small diameter tissue-engineered arteries improve their mechanical and functional properties when they are mechanically stimulated. Applying a suitable stress and/or strain with or without a cycle to the scaffolds and cells during the culturing process resides in our ability to generate a suitable mechanical model. Collagen gel is one of the most used scaffolds in vascular tissue engineering, mainly because it is the principal constituent of the extracellular matrix for vascular cells in human. The mechanical modeling of such a material is not a trivial task, mainly for its viscoelastic nature. Computational and experimental methods for developing a suitable model for collagen gels are of primary importance for the field. In this research, we focused on mechanical properties of collagen gels under unconfined compression. First, mechanical viscoelastic models are discussed and framed in the control system theory. Second, models are fitted using system identification. Several models are evaluated and two nonlinear models are proposed: Mooney-Rivlin inspired and Hammerstein models. The results suggest that Mooney-Rivlin and Hammerstein models succeed in describing the mechanical behavior of collagen gels for cyclic tests on scaffolds (with best fitting parameters 58.3% and 75.8%, resp.). When Akaike criterion is used, the best is the Mooney-Rivlin inspired model. PMID:25834840

  9. Mathematical modeling of uniaxial mechanical properties of collagen gel scaffolds for vascular tissue engineering.

    PubMed

    Irastorza, Ramiro M; Drouin, Bernard; Blangino, Eugenia; Mantovani, Diego

    2015-01-01

    Small diameter tissue-engineered arteries improve their mechanical and functional properties when they are mechanically stimulated. Applying a suitable stress and/or strain with or without a cycle to the scaffolds and cells during the culturing process resides in our ability to generate a suitable mechanical model. Collagen gel is one of the most used scaffolds in vascular tissue engineering, mainly because it is the principal constituent of the extracellular matrix for vascular cells in human. The mechanical modeling of such a material is not a trivial task, mainly for its viscoelastic nature. Computational and experimental methods for developing a suitable model for collagen gels are of primary importance for the field. In this research, we focused on mechanical properties of collagen gels under unconfined compression. First, mechanical viscoelastic models are discussed and framed in the control system theory. Second, models are fitted using system identification. Several models are evaluated and two nonlinear models are proposed: Mooney-Rivlin inspired and Hammerstein models. The results suggest that Mooney-Rivlin and Hammerstein models succeed in describing the mechanical behavior of collagen gels for cyclic tests on scaffolds (with best fitting parameters 58.3% and 75.8%, resp.). When Akaike criterion is used, the best is the Mooney-Rivlin inspired model.

  10. Detergent-enzymatic decellularization of swine blood vessels: insight on mechanical properties for vascular tissue engineering.

    PubMed

    Pellegata, Alessandro F; Asnaghi, M Adelaide; Stefani, Ilaria; Maestroni, Anna; Maestroni, Silvia; Dominioni, Tommaso; Zonta, Sandro; Zerbini, Gianpaolo; Mantero, Sara

    2013-01-01

    Small caliber vessels substitutes still remain an unmet clinical need; few autologous substitutes are available, while synthetic grafts show insufficient patency in the long term. Decellularization is the complete removal of all cellular and nuclear matters from a tissue while leaving a preserved extracellular matrix representing a promising tool for the generation of acellular scaffolds for tissue engineering, already used for various tissues with positive outcomes. The aim of this work is to investigate the effect of a detergent-enzymatic decellularization protocol on swine arteries in terms of cell removal, extracellular matrix preservation, and mechanical properties. Furthermore, the effect of storage at -80°C on the mechanical properties of the tissue is evaluated. Swine arteries were harvested, frozen, and decellularized; histological analysis revealed complete cell removal and preserved extracellular matrix. Furthermore, the residual DNA content in decellularized tissues was far low compared to native one. Mechanical testings were performed on native, defrozen, and decellularized tissues; no statistically significant differences were reported for Young's modulus, ultimate stress, compliance, burst pressure, and suture retention strength, while ultimate strain and stress relaxation of decellularized vessels were significantly different from the native ones. Considering the overall results, the process was confirmed to be suitable for the generation of acellular scaffolds for vascular tissue engineering.

  11. Manipulation of the mechanical properties of a virus by protein engineering

    PubMed Central

    Carrasco, Carolina; Castellanos, Milagros; de Pablo, Pedro J.; Mateu, Mauricio G.

    2008-01-01

    In a previous study, we showed that the DNA molecule within a spherical virus (the minute virus of mice) plays an architectural role by anisotropically increasing the mechanical stiffness of the virus. A finite element model predicted that this mechanical reinforcement is a consequence of the interaction between crystallographically visible, short DNA patches and the inner capsid wall. We have now tested this model by using protein engineering. Selected amino acid side chains have been truncated to specifically remove major interactions between the capsid and the visible DNA patches, and the effect of the mutations on the stiffness of virus particles has been measured using atomic force microscopy. The mutations do not affect the stiffness of the empty capsid; however, they significantly reduce the difference in stiffness between the DNA-filled virion and the empty capsid. The results (i) reveal that intermolecular interactions between individual chemical groups contribute to the mechanical properties of a supramolecular assembly and (ii) identify specific protein–DNA interactions as the origin of the anisotropic increase in the rigidity of a virus. This study also demonstrates that it is possible to control the mechanical properties of a protein nanoparticle by the rational application of protein engineering based on a mechanical model. PMID:18334651

  12. Detergent-Enzymatic Decellularization of Swine Blood Vessels: Insight on Mechanical Properties for Vascular Tissue Engineering

    PubMed Central

    Pellegata, Alessandro F.; Asnaghi, M. Adelaide; Stefani, Ilaria; Maestroni, Anna; Maestroni, Silvia; Dominioni, Tommaso; Zonta, Sandro; Zerbini, Gianpaolo; Mantero, Sara

    2013-01-01

    Small caliber vessels substitutes still remain an unmet clinical need; few autologous substitutes are available, while synthetic grafts show insufficient patency in the long term. Decellularization is the complete removal of all cellular and nuclear matters from a tissue while leaving a preserved extracellular matrix representing a promising tool for the generation of acellular scaffolds for tissue engineering, already used for various tissues with positive outcomes. The aim of this work is to investigate the effect of a detergent-enzymatic decellularization protocol on swine arteries in terms of cell removal, extracellular matrix preservation, and mechanical properties. Furthermore, the effect of storage at −80°C on the mechanical properties of the tissue is evaluated. Swine arteries were harvested, frozen, and decellularized; histological analysis revealed complete cell removal and preserved extracellular matrix. Furthermore, the residual DNA content in decellularized tissues was far low compared to native one. Mechanical testings were performed on native, defrozen, and decellularized tissues; no statistically significant differences were reported for Young's modulus, ultimate stress, compliance, burst pressure, and suture retention strength, while ultimate strain and stress relaxation of decellularized vessels were significantly different from the native ones. Considering the overall results, the process was confirmed to be suitable for the generation of acellular scaffolds for vascular tissue engineering. PMID:23865072

  13. Absorption spectrum, mass spectrometric properties, and electronic structure of 1,2-benzoquinone.

    PubMed

    Albarran, Guadalupe; Boggess, William; Rassolov, Vitaly; Schuler, Robert H

    2010-07-22

    Absorption spectrophotometric and mass spectrometric properties of 1,2-benzoquinone, prepared in aqueous solution by the hexachloroiridate(IV) oxidation of catechol and isolated by HPLC, are reported. Its absorption spectrum has a broad moderately intense band in the near UV with an extinction coefficient of 1370 M(-1)cm(-1) at its 389 nm maximum. The oscillator strength of this band contrasts with those of the order-of-magnitude stronger approximately 250 nm bands of most 1,4-benzoquinones. Gaussian analysis of its absorption spectrum indicates that it also has modestly intense higher energy bands in the 250-320 nm region. In atmospheric pressure mass spectrometric studies 1,2-benzoquinone exhibits very strong positive and negative mass 109 signals that result from the addition of protons and hydride ions in APCI and ESI ion sources. It is suggested that the hydride adduct is formed as the result of the highly polar character of ortho-quinone. On energetic collision the hydride adduct loses an H atom to produce the 1,2-benzosemiquinone radical anion. The present studies also show that atmospheric pressure mass spectral patterns observed for catechol are dominated by signals of 1,2-benzoquinone resulting from oxidation of catechol in the ion sources. Computational studies of the electronic structures of 1,2-benzoquinone, its proton and hydride ion adducts, and 1,2-benzosemiquinone radical anion are reported. These computational studies show that the structures of the proton and hydride adducts are similar and indicate that the hydride adduct is the proton adduct of a doubly negatively charged 1,2-benzoquinone. The contrast between the properties of 1,2- and 1,4-benzoquinone provides the basis for considerations on the effects of conjugation in aromatic systems.

  14. Surface modification and property analysis of biomedical polymers used for tissue engineering.

    PubMed

    Ma, Zuwei; Mao, Zhengwei; Gao, Changyou

    2007-11-15

    The response of host organism in macroscopic, cellular and protein levels to biomaterials is, in most cases, closely associated with the materials' surface properties. In tissue engineering, regenerative medicine and many other biomedical fields, surface engineering of the bio-inert synthetic polymers is often required to introduce bioactive species that can promote cell adhesion, proliferation, viability and enhanced ECM-secretion functions. Up to present, a large number of surface engineering techniques for improving biocompatibility have been well established, the work of which generally contains three main steps: (1) surface modification of the polymeric materials; (2) chemical and physical characterizations; and (3) biocompatibility assessment through cell culture. This review focuses on the principles and practices of surface engineering of biomedical polymers with regards to particular aspects depending on the authors' research background and opinions. The review starts with an introduction of principles in designing polymeric biomaterial surfaces, followed by introduction of surface modification techniques to improve hydrophilicity, to introduce reactive functional groups and to immobilize functional protein molecules. The chemical and physical characterizations of the modified biomaterials are then discussed with emphasis on several important issues such as surface functional group density, functional layer thickness, protein surface density and bioactivity. Three most commonly used surface composition characterization techniques, i.e. ATR-FTIR, XPS, SIMS, are compared in terms of their penetration depth. Ellipsometry, CD, EPR, SPR and QCM's principles and applications in analyzing surface proteins are introduced. Finally discussed are frequently applied methods and their principles to evaluate biocompatibility of biomaterials via cell culture. In this section, current techniques and their developments to measure cell adhesion, proliferation, morphology

  15. Nanohydroxyapatite Effect on the Degradation, Osteoconduction and Mechanical Properties of Polymeric Bone Tissue Engineered Scaffolds

    PubMed Central

    Salmasi, Shima; Nayyer, Leila; Seifalian, Alexander M.; Blunn, Gordon W.

    2016-01-01

    BACKGROUND Statistical reports show that every year around the world approximately 15 million bone fractures occur; of which up to 10% fail to heal completely and hence lead to complications of non-union healing. In the past, autografts or allografts were used as the “gold standard” of treating such defects. However, due to various limitations and risks associated with these sources of bone grafts, other avenues have been extensively investigated through which bone tissue engineering; in particular engineering of synthetic bone graft substitutes, has been recognised as a promising alternative to the traditional methods. METHODS A selective literature search was performed. RESULTS Bone tissue engineering offers unlimited supply, eliminated risk of disease transmission and relatively low cost. It could also lead to patient specific design and manufacture of implants, prosthesis and bone related devices. A potentially promising building block for a suitable scaffold is synthetic nanohydroxyapatite incorporated into synthetic polymers. Incorporation of nanohydroxyapatite into synthetic polymers has shown promising bioactivity, osteoconductivity, mechanical properties and degradation profile compared to other techniques previously considered. CONCLUSION Scientific research, through extensive physiochemical characterisation, in vitro and in vivo assessment has brought together the optimum characteristics of nanohydroxyapatite and various types of synthetic polymers in order to develop nanocomposites of suitable nature for bone tissue engineering. The aim of the present article is to review and update various aspects involved in incorporation of synthetic nanohydroxyapatite into synthetic polymers, in terms of their potentials to promote bone growth and regeneration in vitro, in vivo and consequently in clinical applications. PMID:28217213

  16. The left ventricle as a mechanical engine: from Leonardo da Vinci to the echocardiographic assessment of peak power output-to-left ventricular mass.

    PubMed

    Dini, Frank L; Guarini, Giacinta; Ballo, Piercarlo; Carluccio, Erberto; Maiello, Maria; Capozza, Paola; Innelli, Pasquale; Rosa, Gian M; Palmiero, Pasquale; Galderisi, Maurizio; Razzolini, Renato; Nodari, Savina

    2013-03-01

    The interpretation of the heart as a mechanical engine dates back to the teachings of Leonardo da Vinci, who was the first to apply the laws of mechanics to the function of the heart. Similar to any mechanical engine, whose performance is proportional to the power generated with respect to weight, the left ventricle can be viewed as a power generator whose performance can be related to left ventricular mass. Stress echocardiography may provide valuable information on the relationship between cardiac performance and recruited left ventricular mass that may be used in distinguishing between adaptive and maladaptive left ventricular remodeling. Peak power output-to-mass, obtained during exercise or pharmacological stress echocardiography, is a measure that reflects the number of watts that are developed by 100 g of left ventricular mass under maximal stimulation. Power output-to-mass may be calculated as left ventricular power output per 100 g of left ventricular mass: 100× left ventricular power output divided by left ventricular mass (W/100 g). A simplified formula to calculate power output-to-mass is as follows: 0.222 × cardiac output (l/min) × mean blood pressure (mmHg)/left ventricular mass (g). When the integrity of myocardial structure is compromised, a mismatch becomes apparent between maximal cardiac power output and left ventricular mass; when this occurs, a reduction of the peak power output-to-mass index is observed.

  17. Reversible Tuning of Individual Carbon Nanotube Mechanical Properties via Defect Engineering.

    PubMed

    Zhang, Bin; Zhao, Longze; Cheng, Yong; Golberg, Dmitri; Wang, Ming-Sheng

    2016-08-10

    The structural defects that inevitably exist in real-world carbon nanotubes (CNTs) are generally considered undesirable because they break the structural perfection and may result in drastically degraded CNT properties. On the other hand, the deliberate defect introduction can provide a possibility to tailor the tube mechanical properties. Herein, we present a fully controllable technique to handle defects by using in situ transmission electron microscopy (TEM). Young's modulus, quality factor of the resonation and tensile strength of CNTs can be controllably, reversibly, and repeatedly tuned. Parallel high-resolution visualizing of structural defects suggests that the property tuning cycles are primarily attributed to the reversible conversion of defects at the atomic scale: the defects are created in the form of vacancies and interstitials under electron irradiation, and they vanish through the recombination via current-induced annealing. For applications, such as reversible frequency-tuned CNT resonators, this defect-engineering technique is demonstrated to be uniquely precise; the frequency may be tuned with 0.1%/min accuracy, improved by 1 order of magnitude compared with the existing approaches. We believe that these results will be highly valuable in a variety of property-tunable CNT-based composites and devices.

  18. Mechanical properties of native and tissue-engineered cartilage depend on carrier permeability: a bioreactor study.

    PubMed

    Hoenig, Elisa; Leicht, Uta; Winkler, Thomas; Mielke, Gabriela; Beck, Katharina; Peters, Fabian; Schilling, Arndt F; Morlock, Michael M

    2013-07-01

    The implantation of osteochondral constructs-tissue-engineered (TE) cartilage on a bone substitute carrier-is a promising method to treat defects in articular cartilage. Currently, however, the TE cartilage's mechanical properties are clearly inferior to those of native cartilage. Their improvement has been the subject of various studies, mainly focusing on growth factors and physical loading during cultivation. With the approach of osteochondral constructs another aspect arises: the permeability of the carrier materials. The purpose of this study was to investigate whether and how the permeability of the subchondral bone influences the properties of native cartilage and whether the bone substitute carrier's permeability influences the TE cartilage of osteochondral constructs accordingly. Consequently, the influence of the subchondral bone's permeability on native cartilage was determined: Native porcine cartilage-bone cylinders were cultivated for 2 weeks in a bioreactor under mechanical loading with and without restricted permeability of the bone. For the TE cartilage these two permeability conditions were investigated using permeable and impermeable tricalciumphosphate carriers under equivalent cultivation conditions. All specimens were evaluated mechanically, biochemically, and histologically. The restriction of the bone's permeability significantly decreased the Young's modulus of native cartilage in vitro. No biochemical differences were found. This finding was confirmed for TE cartilage: While the biochemical parameters were not affected, a permeable carrier improved the cell morphology and mechanical properties in comparison to an impermeable one. In conclusion, the carrier permeability was identified as a determining factor for the mechanical properties of TE cartilage of osteochondral constructs.

  19. Long-term stability and properties of zirconia ceramics for heavy duty diesel engine components

    NASA Technical Reports Server (NTRS)

    Larsen, D. C.; Adams, J. W.

    1985-01-01

    Physical, mechanical, and thermal properties of commercially available transformation-toughened zirconia are measured. Behavior is related to the material microstructure and phase assemblage. The stability of the materials is assessed after long-term exposure appropriate for diesel engine application. Properties measured included flexure strength, elastic modulus, fracture toughness, creep, thermal shock, thermal expansion, internal friction, and thermal diffusivity. Stability is assessed by measuring the residual property after 1000 hr/1000C static exposure. Additionally static fatigue and thermal fatigue testing is performed. Both yttria-stabilized and magnesia-stabilized materials are compared and contrasted. The major limitations of these materials are short term loss of properties with increasing temperature as the metastable tetragonal phase becomes more stable. Fine grain yttria-stabilized material (TZP) is higher strength and has a more stable microstructure with respect to overaging phenomena. The long-term limitation of Y-TZP is excessive creep deformation. Magnesia-stabilized PSZ has relatively poor stability at elevated temperature. Overaging, decomposition, and/or destabilization effects are observed. The major limitation of Mg-PSZ is controlling unwanted phase changes at elevated temperature.

  20. Three-Dimensional Properties of Coronal Mass Ejections from STEREO/SECCHI Observations

    DTIC Science & Technology

    2012-01-01

    Solar Phys DOI 10.1007/s11207-012-0123-5 T H E S U N 3 6 0 Three-Dimensional Properties of Coronal Mass Ejections from STEREO/SECCHI Observations E...Bosman · V. Bothmer · G. Nisticò · A. Vourlidas · R.A. Howard · J.A. Davies Received: 15 November 2011 / Accepted: 4 September 2012 © The Author(s...structure and model them as three-dimensional (3D) flux ropes using a forward- modeling technique developed by Thernisien, Howard and Vourlidas (Astrophys

  1. Examining the relation between rock mass cuttability index and rock drilling properties

    NASA Astrophysics Data System (ADS)

    Yetkin, Mustafa E.; Özfırat, M. Kemal; Yenice, Hayati; Şimşir, Ferhan; Kahraman, Bayram

    2016-12-01

    Drilling rate is a substantial index value in drilling and excavation operations at mining. It is not only a help in determining physical and mechanical features of rocks, but also delivers strong estimations about instantaneous cutting rates. By this way, work durations to be finished on time, proper machine/equipment selection and efficient excavation works can be achieved. In this study, physical and mechanical properties of surrounding rocks and ore zones are determined by investigations carried out on specimens taken from an underground ore mine. Later, relationships among rock mass classifications, drillability rates, cuttability, and abrasivity have been investigated using multi regression analysis. As a result, equations having high regression rates have been found out among instantaneous cutting rates and geomechanical properties of rocks. Moreover, excavation machine selection for the study area has been made at the best possible interval.

  2. The evaluation of properties of coal mass from the viewpoint of environment

    SciTech Connect

    Foniok, R.; Lukes, M.

    1995-12-01

    This paper deals with the evaluation of several various coal kinds from the Czech coalfields from the viewpoint of the development of thermal processes in coal mass due to their tendency towards self- ignition during storing. In such a case that no self-ignition during storing occurs, gaseous products are liberated into air, the quantity and composition of which depend upon fuel type and its temperature as well. From the environmental viewpoint, substances washed from stored coal are of a certain interest, too. In accordance with this fact, the importance of measures against self-heating of stored coal mass and the importance of a detailed observation of coal quality are concluded. The tables, which compare various coal kinds from the viewpoint of their behavior at self-ignition processes, are the integral part of this presented paper. Our greatest attention is paid to both the quantity and composition of gases being liberated in dependence upon the temperature of coal mass, and at its crushing with regard to selected methods and means of milling circuits before and explosion. Oxygen sorption by means of coal mass is also observed, being of a great importance for self-inertization of closed tanks. All the above-mentioned processes are demonstrated in form of graphic plots. Qualitative signs of coal mass are the basic means for its assessment from the viewpoint of emissions at burning/combustion, and the evaluation of explosive properties. A great attention is paid to explosion-proof means being produced in the Czech Republic. These means can be used for protection of milling circuits of power plants and heating plants or for safety systems of combustion chamber by means of insulation to secondary air main. Explosion-proof quci-acting valves, a special type of safety membrane and device for explosion suppression nip in the bud do represent the latest explosion-proof means.

  3. Sensitivity of simulated snow cloud properties to mass-diameter parameterizations.

    NASA Astrophysics Data System (ADS)

    Duffy, G.; Nesbitt, S. W.; McFarquhar, G. M.

    2015-12-01

    Mass to diameter (m-D) relationships are used in model parameterization schemes to represent ice cloud microphysics and in retrievals of bulk cloud properties from remote sensing instruments. One of the most common relationships, used in the current Global Precipitation Measurement retrieval algorithm for example, assigns the density of snow as a constant tenth of the density of ice (0.1g/m^3). This assumption stands in contrast to the results of derived m-D relationships of snow particles, which imply decreasing particle densities at larger sizes and result in particle masses orders of magnitude below the constant density relationship. In this study, forward simulations of bulk cloud properties (e.g., total water content, radar reflectivity and precipitation rate) derived from measured size distributions using several historical m-D relationships are presented. This expands upon previous studies that mainly focused on smaller ice particles because of the examination of precipitation-sized particles here. In situ and remote sensing data from the GPM Cold season Experiment (GCPEx) and Canadian CloudSAT/Calypso Validation Program (C3VP), both synoptic snowstorm field experiments in southern Ontario, Canada, are used to evaluate the forward simulations against total water content measured by the Nevzorov and Cloud Spectrometer and Impactor (CSI) probe, radar reflectivity measured by a C band ground based radar and a nadir pointing Ku/Ka dual frequency airborne radar, and precipitation rate measured by a 2D video disdrometer. There are differences between the bulk cloud properties derived using varying m-D relations, with constant density assumptions producing results differing substantially from the bulk measured quantities. The variability in bulk cloud properties derived using different m-D relations is compared against the natural variability in those parameters seen in the GCPEx and C3VP field experiments.

  4. Internalisation of engineered nanoparticles into mammalian cells in vitro: influence of cell type and particle properties

    NASA Astrophysics Data System (ADS)

    Busch, Wibke; Bastian, Susanne; Trahorsch, Ulrike; Iwe, Maria; Kühnel, Dana; Meißner, Tobias; Springer, Armin; Gelinsky, Michael; Richter, Volkmar; Ikonomidou, Chrysanthy; Potthoff, Annegret; Lehmann, Irina; Schirmer, Kristin

    2011-01-01

    Cellular internalisation of industrial engineered nanoparticles is undesired and a reason for concern. Here we investigated and compared the ability of seven different mammalian cell cultures in vitro to incorporate six kinds of engineered nanoparticles, focussing on the role of cell type and particle properties in particle uptake. Uptake was examined using light and electron microscopy coupled with energy dispersive X-ray spectroscopy (EDX) for particle element identification. Flow cytometry was applied for semi-quantitative analyses of particle uptake and for exploring the influence on uptake by the phagocytosis inhibitor Cytochalasin D (CytoD). All particles studied were found to enter each kind of cultured cells. Yet, particles were never found within cell nuclei. The presence of the respective particles within the cells was confirmed by EDX. Live-cell imaging revealed the time-dependent process of internalisation of technical nanoparticles, which was exemplified by tungsten carbide particle uptake into the human skin cells, HaCaT. Particles were found to co-localise with lysosomal structures within the cells. The incorporated nanoparticles changed the cellular granularity, as measured by flow cytometry, already after 3 h of exposure in a particle specific manner. By correlating particle properties with flow cytometry data, only the primary particle size was found to be a weakly influential property for particle uptake. CytoD, an inhibitor of actin filaments and therewith of phagocytosis, significantly inhibited the internalisation of particle uptake in only two of the seven investigated cell cultures. Our study, therefore, supports the notion that nanoparticles can enter mammalian cells quickly and easily, irrespective of the phagocytic ability of the cells.

  5. Characterization of the human plasma phosphoproteome using linear ion trap mass spectrometry and multiple search engines.

    PubMed

    Carrascal, Montserrat; Gay, Marina; Ovelleiro, David; Casas, Vanessa; Gelpí, Emilio; Abian, Joaquin

    2010-02-05

    Major plasma protein families play different roles in blood physiology and hemostasis and in immunodefense. Other proteins in plasma can be involved in signaling as chemical messengers or constitute biological markers of the status of distant tissues. In this respect, the plasma phosphoproteome holds potentially relevant information on the mechanisms modulating these processes through the regulation of protein activity. In this work we describe for the first time a collection of phosphopeptides identified in human plasma using immunoaffinity separation of the seven major serum protein families from other plasma proteins, SCX fractionation, and TiO(2) purification prior to LC-MS/MS analysis. One-hundred and twenty-seven phosphosites in 138 phosphopeptides mapping 70 phosphoproteins were identified with FDR < 1%. A high-confidence collection of phosphosites was obtained using a combined search with the OMSSA, SEQUEST, and Phenyx search engines.

  6. A new approach to the correlation of boundary layer mass transfer rates with thermal diffusion and/or variable properties

    NASA Technical Reports Server (NTRS)

    Srivastava, R.; Rosner, D. E.

    1979-01-01

    A rational approach to the correlation of boundary layer mass transport rates, applicable to many commonly encountered laminar flow conditions with thermal diffusion and/or variable properties, is outlined. The correlation scheme builds upon already available constant property blowing/suction solutions by introducing appropriate correction factors to account for the additional ('pseudo' blowing and source) effects identified with variable properties and thermal diffusion. Applications of the scheme to the particular laminar boundary layer mass transfer problems considered herein (alkali and transition metal compound vapor transport) indicates satisfactory accuracy up to effective blowing factors equivalent to about one third of the 'blow off' value. As a useful by-product of the variable property correlation, we extend the heat-mass transfer analogy, for a wide range of Lewis numbers, to include variable property effects.

  7. Novel models on fluid's variable thermo-physical properties for extensive study on convection heat and mass transfer

    NASA Astrophysics Data System (ADS)

    Shang, De-Yi; Zhong, Liang-Cai

    2017-01-01

    Our novel models for fluid's variable physical properties are improved and reported systematically in this work for enhancement of theoretical and practical value on study of convection heat and mass transfer. It consists of three models, namely (1) temperature parameter model, (2) polynomial model, and (3) weighted-sum model, respectively for treatment of temperature-dependent physical properties of gases, temperature-dependent physical properties of liquids, and concentration- and temperature-dependent physical properties of vapour-gas mixture. Two related components are proposed, and involved in each model for fluid's variable physical properties. They are basic physic property equations and theoretical similarity equations on physical property factors. The former, as the foundation of the latter, is based on the typical experimental data and physical analysis. The latter is built up by similarity analysis and mathematical derivation based on the former basic physical properties equations. These models are available for smooth simulation and treatment of fluid's variable physical properties for assurance of theoretical and practical value of study on convection of heat and mass transfer. Especially, so far, there has been lack of available study on heat and mass transfer of film condensation convection of vapour-gas mixture, and the wrong heat transfer results existed in widespread studies on the related research topics, due to ignorance of proper consideration of the concentration- and temperature-dependent physical properties of vapour-gas mixture. For resolving such difficult issues, the present novel physical property models have their special advantages.

  8. Influence of air mass origin on aerosol properties at a remote Michigan forest site

    NASA Astrophysics Data System (ADS)

    VanReken, T. M.; Mwaniki, G. R.; Wallace, H. W.; Pressley, S. N.; Erickson, M. H.; Jobson, B. T.; Lamb, B. K.

    2015-04-01

    The northern Great Lakes region of North America is a large, relatively pristine area. To date, there has only been limited study of the atmospheric aerosol in this region. During summer 2009, a detailed characterization of the atmospheric aerosol was conducted at the University of Michigan Biological Station (UMBS) as part of the Community Atmosphere-Biosphere Interactions Experiment (CABINEX). Measurements included particle size distribution, water-soluble composition, and CCN activity. Aerosol properties were strongly dependent on the origin of the air masses reaching the site. For ∼60% of the study period, air was transported from sparsely populated regions to the northwest. During these times aerosol loadings were low, with mean number and volume concentrations of 1630 cm-3 and 1.91 μm3 cm-3, respectively. The aerosol during clean periods was dominated by organics, and exhibited low hygroscopicities (mean κ = 0.18 at s = 0.3%). When air was from more populated regions to the east and south (∼29% of the time), aerosol properties reflected a stronger anthropogenic influence, with 85% greater particle number concentrations, 2.5 times greater aerosol volume, six times more sulfate mass, and increased hygroscopicity (mean k = 0.24 at s = 0.3%). These trends are have the potential to influence forest-atmosphere interactions and should be targeted for future study.

  9. Biocatalytic Lactone Generation in Genetically Engineered Escherichia coli and Identification of Products by Gas Chromatography-Mass Spectroscopy

    NASA Astrophysics Data System (ADS)

    Slawson, Chad; Stewart, Jon; Potter, Robert

    2001-11-01

    Genetically altered Escherichia coli are used as biocatalysts to produce optically pure lactones from a variety of cyclic ketones as a biotechnology experiment for a biochemistry laboratory. The genetically engineered E. coli bacteria express large amounts of the enzyme cyclohexanone monooxygenase and are therefor capable of converting a variety of ketones into optically pure lactones. Separation by organic extraction and analysis by thin layer chromatography and gas chromatography-mass spectroscopy allows for the direct identification of products. Yield calculations and evaluation of the cost effectiveness of various substrates give students an opportunity to make recommendations and model industrial decision-making. Evaluation of the synthetic process for its environmental impact allows students to consider problems of cost versus environmental concerns. Use of bacterial biocatalysts offers chemistry students an opportunity to work with microorganisms and directly see the utility of genetically altered bacteria for synthetic chemistry.

  10. The impact of mass flow and masking on the pressure drop of air filter in heavy-duty diesel engine

    NASA Astrophysics Data System (ADS)

    Hoseeinzadeh, Sepideh; Gorji-Bandpy, Mofid

    2012-04-01

    This paper presents a computational fluid dynamics (CFD) calculation approach to predict and evaluate the impact of the mass-flow inlet on the pressure drop of turbocharger`s air filtfer in heavy-duty diesel engine. The numerical computations were carried out using a commercial CFD program whereas the inlet area of the air filter consisted of several holes connected to a channel. After entering through the channel, the air passes among the holes and enters the air filter. The effect of masking holes and hydraulic diameter is studied and investigated on pressure drop. The results indicate that pressure drop increase with decreasing of hydraulic diameter and masking of the holes has considerable affect on the pressure drop.

  11. Water mass properties and chemical signatures in the central Mediterranean region

    NASA Astrophysics Data System (ADS)

    Astraldi, M.; Conversano, F.; Civitarese, G.; Gasparini, G. P.; Ribera d'Alcalà, M.; Vetrano, A.

    2002-06-01

    During the last 15 years, the knowledge of Mediterranean physical dynamics as well as of atmospheric forcing underwent a tremendous improvement because of the action within several international programs and the development of remote sensing and modelling approaches. Curiously, it is still very difficult to build up a climatological database for chemical and basic biological parameters for the whole basin because most of the data published in the open literature were preferentially related to meso- to small-scale processes. Within the European Union project Mass Transfer and Ecosystem Response (MATER), systematic measurements of routine chemical parameters, such as dissolved oxygen and nutrients, have been conducted. They will fill the existing gap between physical and chemical information. In this paper, we analyze the hydrographic data from a cruise conducted in the fall 1996 in the Central Mediterranean region and report, for the first time, on oxygen and nutrient concentrations, ranges and distributions. The joint analysis of T- S properties and chemical data also allows a better definition of water mass characteristics in this crucial area and hints at basic mechanisms relevant to water mass transformation and biological production in the basin.

  12. Core mass at the helium flash from observations and a new bound on neutrino electromagnetic properties

    NASA Technical Reports Server (NTRS)

    Raffelt, Georg G.

    1990-01-01

    Existing measurements of the bolometric magnitudes of the brightest red giants in 26 globular clusters are used to determine the brightness difference between the tip of the red giant branch (on average found to be 0.1 mag brighter than the brightest red giant) and RR Lyrae stars. The metallicity variation of the result agrees perfectly with theoretical predictions. In conjunction with previous determinations of the number ratio of horizontal-branch versus red giant stars, with statistical parallax determinations of RR Lyrae absolute luminosities, and with theoretical predictions based on the Sweigart and Gross evolutionary sequences, this result yields an allowed range for a hypothetical core mass variation relative to the standard results of (0.009 + or - 0.012) solar mass. If neutrinos had anomalous electromagnetic dipole moments, the increased energy loss near the helium flash would lead to an increased core mass. Constraints on neutrino electromagnetic properties are determined from the color-magnitude diagrams of the globular clusters.

  13. Analysis of petrol and diesel vapour and vehicle engine exhaust gases using selected ion flow tube mass spectrometry.

    PubMed

    Smith, David; Cheng, Ping; Spanel, Patrik

    2002-01-01

    We have used selected ion flow tube mass spectrometry (SIFT-MS) to analyse the vapours emitted by petrol and diesel fuels and the exhaust gases from petrol (spark ignition) and diesel (compression ignition) engine vehicles fitted with catalytic converters. Only those components of these media that have significant vapour pressures at ambient temperatures were analysed and thus particulates were obviously not detected. These media have been analysed using the full scope of SIFT-MS, i.e., with the three available precursor ions H3O+, NO+ and O2+. The combination of the H3O+ and NO+ analyses is seen to be essential to distinguish between different product ions at the same mass-to-charge ratio (m/z) especially in identifying aldehydes in the exhaust gases. The O2+ precursor ions are used to detect and quantify the large amount of nitric oxide present in the exhaust gases from both engine types. The petrol and diesel vapours consist almost exclusively of aliphatic alkanes, alkenes and alkynes (and dienes) and aromatic hydrocarbons. Some of these compounds appear in the exhaust gases together with several aldehydes, viz. formaldehyde, acetaldehyde, pentanal, pentenal (acrolein), butenal, and also methanol and ethanol. Acetone, nitric oxide and ammonia are also present, acetone and nitric oxide being much more abundant in the diesel exhaust gas than in the petrol exhaust gas. These data were obtained from samples collected into pre-evacuated stainless steel vessels. Trapping of the volatile compounds from the gas samples is not required and analysis was completed a few minutes later. All the above compounds are detected simultaneously, which demonstrates the value of SIFT-MS in this area of research.

  14. Synthetically engineered chitosan-based materials and their sorption properties with methylene blue in aqueous solution.

    PubMed

    Guo, Rui; Wilson, Lee D

    2012-12-15

    Chitosan (CS) and poly(acrylic acid) (PAA) were crosslinked by an ionic gelation method to form super absorbent polymers (SAPs). CS and PAA form amide bonds between the amino and carboxyl groups. The CS-PAA copolymers were synthetically engineered by varying the feed ratios of the prepolymer units. The copolymer materials possess tunable sorption and mucoadhesive properties with a backbone structure resembling proteinaceous materials. The sorption properties of the copolymers toward methylene blue (MB) in aqueous solution were studied using UV-Vis spectrophotometry at ambient pH and 295 K. The copolymers showed markedly varied interactions with MB, from physisorption- to chemisorption-like behavior, in accordance with their composition, surface area, and pore structure characteristics. The sorption isotherms were evaluated with the Sips model to provide estimates of the sorption properties. The sorbent surface area (271 and 943 m(2)/g) and the sorption capacity (Q(m)=1.03 and 3.59 mmol/g) were estimated for the CS-PAA copolymer/MB systems in aqueous solution.

  15. Small Particles - Big Change? Engineered Nanomaterial Effects on Soil Subsurface Properties

    NASA Astrophysics Data System (ADS)

    Dror, I.; Yaron, B.; Berkowitz, B.

    2014-12-01

    A large number of research papers on the fate of engineered nanomaterials (ENMs) in the soil-water system have appeared in recent years, focusing on ENM transport, persistence and toxicological impact. However, very few studies have examined the impact of ENMs on the natural soil-subsurface matrix and its properties. Potential irreversible changes to natural soil-subsurface systems that originate from contact with other chemical contaminants of anthropogenic origin have been noted previously. Such changes are considered to have a substantial impact on the liquid phase and solid matrix properties. ENMs reach the land surface through many pathways during and after their beneficial use. Once in the soil, ENMs move as suspended particles in aqueous solution. Dissolution, aggregation and deposition are the primary processes governing their interaction with the soil solid phase and their redistribution from the land surface to the groundwater. We argue that irreversible deposition of ENMs occurring under specific conditions (e.g., in arid and semi-arid environments) may lead to irreversible changes in soil matrix structure and properties. Results from our research on metal and metal oxides ENMs (e.g., CuO, Ag) and from literature on carbon based nanomaterials will be presented in support of our hypothesis.

  16. Tailoring the emissive properties of photocathodes through materials engineering: Ultra-thin multilayers

    NASA Astrophysics Data System (ADS)

    Velázquez, Daniel; Seibert, Rachel; Ganegoda, Hasitha; Olive, Daniel; Rice, Amy; Logan, Kevin; Yusof, Zikri; Spentzouris, Linda; Terry, Jeff

    2016-01-01

    We report on an experimental verification that emission properties of photocathodes can be manipulated through the engineering of the surface electronic structure. Ultrathin multilayered MgO/Ag(0 0 1)/MgO films were grown by pulsed laser deposition, tuning the thickness n of the flanking MgO layers to 0, 2, 3, and 4 monolayers. We observed an increase in quantum efficiency and simultaneous decrease in work function with layer thickness. The scale and trend direction of measurements are in good but not excellent agreement with theory. Angle resolved photoemission data for the multilayered sample n = 3 showed that the emission profile has a metallic-like momentum dispersion. Deviations from theoretical predictions [K. Németh et al., PRL 104, 046801 (2010)] are attributed to imperfections of real surfaces in contrast with the ideal surfaces of the calculation. Photoemissive properties of cathodes are critical for electron beam applications such as photoinjectors for Free Electron Lasers (FEL) and Energy Recovery Linacs (ERL). An ideal photoemitter has a high quantum efficiency, low work function, low intrinsic emittance and long lifetime. It has been demonstrated here that emission properties may be systematically tailored by control of layer thickness in ultrathin multilayered structures. The reproducibility of the emission parameters under specific growth conditions is excellent, even though the interfaces themselves have varying degrees of roughness.

  17. Feasibility Study of a Pressure-fed Engine for a Water Recoverable Space Shuttle Booster

    NASA Technical Reports Server (NTRS)

    Gerstl, E.

    1972-01-01

    Detailed mass properties are presented for a gimbaled, fixed thrust, regeneratively cooled engine having a coaxial pintle injector. The baseline design parameters for this engine are tabulated. Mass properties are also summarized for several other engine configurations i.e., a hinge nozzle using a Techroll seal, a gimbaled duct cooled engine and a regeneratively cooled engine using liquid injection thrust vector control (LITVC). Detailed engine analysis and design trade studies leading to the selection of a regeneratively cooled gimbaled engine and pertaining to the selection of the baseline design configuration are also given.

  18. Lipopolysaccharide engineering in Neisseria meningitidis: structural analysis of different pentaacyl lipid A mutants and comparison of their modified agonist properties.

    PubMed

    Pupo, Elder; Hamstra, Hendrik-Jan; Meiring, Hugo; van der Ley, Peter

    2014-03-21

    Engineering the lipopolysaccharide (LPS) biosynthetic pathway offers the potential to obtain modified derivatives with optimized adjuvant properties. Neisseria meningitidis strain H44/76 was modified by expression of the pagL gene encoding lipid A 3-O-deacylase from Bordetella bronchiseptica and by inactivation of the lgtB gene encoding the terminal oligosaccharide galactosyltransferase. Mass spectrometry analysis of purified mutant LPS was used for detailed compositional analysis of all present molecular species. This determined that the modified LPS was mainly pentaacylated, demonstrating high efficiency of conversion from the hexaacyl to the 3-O-deacylated form by heterologous lipid A 3-O-deacylase (PagL) expression. MS analyses also provided evidence for expression of only one major oligosaccharide glycoform, which lacked the terminal galactose residue as expected from inactivation of the lgtB gene. The immunomodulatory properties of PagL-deacylated LPS were compared with another pentaacyl form obtained from an lpxL1(-) mutant, which lacks the 2' secondary acyl chain. Although both LPS mutants displayed impaired capacity to induce production of the pro-inflammatory cytokine IL-6 in the monocytic cell line Mono Mac 6, induction of the Toll-interleukin-1 receptor domain-containing adaptor-inducing interferon-β-dependent chemokine interferon-γ-induced protein 10 was largely retained only for the lgtB(-)/pagL(+) mutant. Removal of remaining hexaacyl species exclusively present in lgtB(-)/pagL(+) LPS demonstrated that these minor species potentiate but do not determine the activity of this LPS. These results are the first to indicate a qualitatively different response of human innate cells to pentaacyl lpxL1(-) and pagL(+) LPS and show the importance of detailed structure-function analysis when working with modified lipid A structures. The pagL(+) LPS has significant potential as immune modulator in humans.

  19. Identification of volatile and semivolatile compounds in chemical ionization GC-MS using a mass-to-structure (MTS) Search Engine with integral isotope pattern ranking.

    PubMed

    Liao, Wenta; Draper, William M

    2013-02-21

    The mass-to-structure or MTS Search Engine is an Access 2010 database containing theoretical molecular mass information for 19,438 compounds assembled from common sources such as the Merck Index, pesticide and pharmaceutical compilations, and chemical catalogues. This database, which contains no experimental mass spectral data, was developed as an aid to identification of compounds in atmospheric pressure ionization (API)-LC-MS. This paper describes a powerful upgrade to this database, a fully integrated utility for filtering or ranking candidates based on isotope ratios and patterns. The new MTS Search Engine is applied here to the identification of volatile and semivolatile compounds including pesticides, nitrosoamines and other pollutants. Methane and isobutane chemical ionization (CI) GC-MS spectra were obtained from unit mass resolution mass spectrometers to determine MH(+) masses and isotope ratios. Isotopes were measured accurately with errors of <4% and <6%, respectively, for A + 1 and A + 2 peaks. Deconvolution of interfering isotope clusters (e.g., M(+) and [M - H](+)) was required for accurate determination of the A + 1 isotope in halogenated compounds. Integrating the isotope data greatly improved the speed and accuracy of the database identifications. The database accurately identified unknowns from isobutane CI spectra in 100% of cases where as many as 40 candidates satisfied the mass tolerance. The paper describes the development and basic operation of the new MTS Search Engine and details performance testing with over 50 model compounds.

  20. The central engine of quasars and AGNs - Scaling to solar mass black holes

    NASA Technical Reports Server (NTRS)

    Kazanas, D.

    1988-01-01

    The model of the previous paper (Ellison and Kazanas, hereafter EK) can be readily scaled to model systems with black holes 3-10 solar masses, such as those expected to exist in certain Galactic X-ray binaries. The model can account in a straightforward way for the bimodal behavior of Cyg X-1 and the other Galactic black hole candidates (White and Marshall 1984; White, et al., 1984). It is argued that the change in the spectrum with luminosity is due to the drastic increase of both the source compactness and luminosity with small changes in the accretion rate, and conversion of most of the energy into electron-positron pairs which render the source optically thick and modify its spectrum. It is also argued that similar effects may be observed in AGNs.

  1. Slow light in mass-produced, dispersion-engineered photonic crystal ring resonators.

    PubMed

    McGarvey-Lechable, Kathleen; Hamidfar, Tabassom; Patel, David; Xu, Luhua; Plant, David V; Bianucci, Pablo

    2017-02-20

    We present experimental results of photonic crystal ring resonators (PhCRRs) fabricated on the CMOS-compatible, silicon-on-insulator platform via 193-nm deep-UV lithography. Our dispersion-engineering design approach is compared to experimental results, showing very good agreement between theory and measurements. Specifically, we report a mean photonic band-edge wavelength of 1546.2 ± 5.8 nm, a 0.2% variation from our targeted band-edge wavelength of 1550 nm. Methods for the direct calculation of the experimental, discrete dispersion relation and extraction of intrinsic quality factors for a highly-dispersive resonator are discussed. A maximum intrinsic quality factor of ≈83,800 is reported, substantiating our design method and indicating that high-throughput optical lithography is a viable candidate for PhCRR fabrication. Finally, through comparison of the mean intrinsic quality and slowdown factors of the PhCRRs and standard ring resonators, we present evidence of an increase in light-matter interaction strength with simultaneous preservation of microcavity lifetimes.

  2. Hydraulic Performance and Mass Transfer Efficiency of Engineering Scale Centrifugal Contactors

    SciTech Connect

    David Meikrantz; Troy Garn; Nick Mann; Jack Law; Terry Todd

    2007-09-01

    Annular centrifugal contactors (ACCs) are being evaluated for process-scale solvent extraction operations in support of Advanced Fuel Cycle Initiative (AFCI) separations goals. Process-scale annular centrifugal contactors have the potential for high stage efficiency if properly employed and optimized for the application. Hydraulic performance issues related to flow instability and classical flooding are likely unimportant, especially for units with high throughputs. However, annular mixing increases rapidly with increasing rotor diameter while maintaining a fixed g force at the rotor wall. In addition, for engineering/process-scale contactors, elevated rotor speeds and/or throughput rates, can lead to organic phase foaming at the rotor discharge collector area. Foam buildup in the upper rotor head area can aspirate additional vapor from the contactor housing resulting in a complete loss of separation equilibrium. Variable speed drives are thus desirable to optimize and balance the operating parameters to help ensure acceptable performance. Proper venting of larger contactors is required to balance pressures across individual stages and prevent vapor lock due to foam aspiration.

  3. Real-time analysis of organic compounds in ship engine aerosol emissions using resonance-enhanced multiphoton ionisation and proton transfer mass spectrometry.

    PubMed

    Radischat, Christian; Sippula, Olli; Stengel, Benjamin; Klingbeil, Sophie; Sklorz, Martin; Rabe, Rom; Streibel, Thorsten; Harndorf, Horst; Zimmermann, Ralf

    2015-08-01

    Organic combustion aerosols from a marine medium-speed diesel engine, capable to run on distillate (diesel fuel) and residual fuels (heavy fuel oil), were investigated under various operating conditions and engine parameters. The online chemical characterisation of the organic components was conducted using a resonance-enhanced multiphoton ionisation time-of-flight mass spectrometer (REMPI TOF MS) and a proton transfer reaction-quadrupole mass spectrometer (PTR-QMS). Oxygenated species, alkenes and aromatic hydrocarbons were characterised. Especially the aromatic hydrocarbons and their alkylated derivatives were very prominent in the exhaust of both fuels. Emission factors of known health-hazardous compounds (e.g. mono- and poly-aromatic hydrocarbons) were calculated and found in higher amounts for heavy fuel oil (HFO) at typical engine loadings. Lower engine loads lead in general to increasing emissions for both fuels for almost every compound, e.g. naphthalene emissions varied for diesel fuel exhaust between 0.7 mg/kWh (75 % engine load, late start of injection (SOI)) and 11.8 mg/kWh (10 % engine load, late SOI) and for HFO exhaust between 3.3 and 60.5 mg/kWh, respectively. Both used mass spectrometric techniques showed that they are particularly suitable methods for online monitoring of combustion compounds and very helpful for the characterisation of health-relevant substances. Graphical abstract Three-dimensional REMPI data of organic species in diesel fuel and heavy fuel oil exhaust.

  4. Issues in nanocomposite ceramic engineering: focus on processing and properties of alumina-based composites.

    PubMed

    Palmero, Paola; Kern, Frank; Sommer, Frank; Lombardi, Mariangela; Gadow, Rainer; Montanaro, Laura

    2014-12-30

    Ceramic nanocomposites, containing at least one phase in the nanometric dimension, have received special interest in recent years. They have, in fact, demonstrated increased performance, reliability and lifetime with respect to monolithic ceramics. However, a successful approach to the production of tailored composite nanostructures requires the development of innovative concepts at each step of manufacturing, from the synthesis of composite nanopowders, to their processing and sintering.This review aims to deepen understanding of some of the critical issues associated with the manufacturing of nanocomposite ceramics, focusing on alumina-based composite systems. Two case studies are presented and briefly discussed. The former illustrates the benefits, in terms of sintered microstructure and related mechanical properties, resulting from the application of an engineering approach to a laboratory-scale protocol for the elaboration of nanocomposites in the system alumina-ZrO2-YAG (yttrium aluminium garnet). The latter illustrates the manufacturing of alumina-based composites for large-scale applications such as cutting tools, carried out by an injection molding process. The need for an engineering approach to be applied in all processing steps is demonstrated also in this second case study, where a tailored manufacturing process is required to obtain the desired results.

  5. Recombinant human gelatin substitute with photoreactive properties for cell culture and tissue engineering.

    PubMed

    Kitajima, Takashi; Obuse, Sei; Adachi, Takahiro; Tomita, Masahiro; Ito, Yoshihiro

    2011-10-01

    The human recombinant collagen I α1 chain monomer (rh-gelatin) was modified by the incorporation of an azidophenyl group to prepare photoreactive human gelatin (Az-rh-gelatin), with approximately 90% of the lysine residues conjugated with azidobenzoic acid. Slight changes in conformation (circular dichroism spectra) and thermal properties (gelation and melting points) were noticed after modification. Ultraviolet (UV) irradiation could immobilize the Az-rh-gelatin on polymer surfaces, such as polystyrene and polytetrafluoroethylene. Az-rh-gelatin was stably retained on the polymer surfaces, while unmodified gelatin was mostly lost by brief washing. Human mesenchymal cells grew more efficiently on the immobilized surface than on the coated surface. The immobilized Az-rh-gelatin on the polymer surfaces was able to capture engineered growth factors with collagen affinity, and the bound growth factors stimulated the growth of cells dose-dependently. It was also possible to immobilize Az-rh-gelatin in micropatterns (stripe, grid, and so on) using photomasks, and the cells grew according to the patterns. These results suggest that the photoreactive human gelatin, in combination with collagen-binding growth factors, will be clinically useful for surface modification of synthetic materials for cell culture systems and tissue engineering.

  6. Engineering properties of water/wastewater-treatment sludge modified by hydrated lime, fly ash and loess.

    PubMed

    Lim, Sungjin; Jeon, Wangi; Lee, Jaebok; Lee, Kwanho; Kim, Namho

    2002-10-01

    The purpose of this research was to present engineering properties of modified sludge from water/wastewater treatment by modifiers such as hydrated lime, loess, and fly ash. The proper mixing ratio was determined to hold the pH of the modified sludge above 12.0 for 2 h. Laboratory tests carried out in this research included particle analysis, compaction and CBR, SEM and X-ray diffraction, unconfined compression test, permeability test, and TCLP test. The main role of lime was to sterilize microorganisms in the sludge. The unconfined strength of the modified sludge by fly ash and loess satisfied the criteria for construction materials, which was above 100 kPa. The permeability of all the mixtures was around 1.0 x 10(-7) cm/s. Extraction tests for hazardous components in modified sludge revealed below the regulated criteria, especially for cadmium, copper, and lead. The present study suggested that the use of lime, fly ash, and loess be an another alternative to modify or stabilize water/wastewater treatment sludge as construction materials in civil engineering.

  7. Identifying and Engineering the Electronic Properties of the Resistive Switching Interface

    NASA Astrophysics Data System (ADS)

    Li, H.; Zhang, Z.; Shi, L. P.

    2016-02-01

    The resistive switching interface is promising for building random access memory devices with electroforming-free characteristics, rectification functionality and highly reproducible resistive switching performance. The electronic structures of the resistive switching interface are important not only from a fundamental point of view, but also from the fascinating perspective of interface engineering for high performance devices. However, the electronic properties of typical resistive switching interfacial structures at an atomic level are less well understood, compared to those of bulky resistive switching structures. In this work, we study the electronic structures of two typical resistive switching interfacial structures, TiO2/Ti4O7 and Ta2O5/TaO2, using the screened exchange (sX-LDA) functional. We uncover that the system Fermi energies of both interfaces are just above the conduction band edge of the corresponding stoichiometric oxides. According to the defect charge transition levels, the oxygen vacancy is stabilized at the -2 charged state in Ta2O5 and TiO2 where the switching takes place. However, it is desirable for the +2 charged oxygen vacancy to be stabilized to achieve controlled resistive switching under the electrical field. We propose to introduce interfacial dopants to shift the system Fermi energies downward so that the +2 charged oxygen vacancy can be stable. Several dipole models are presented to account for the ability of the Fermi level to shift due to the interfacial dopants. These methods are readily applicable to interface engineering for high performance devices.

  8. Displaying and evaluating engineering properties and natural hazards using geomorphic mapping techniques: Telluride, Colorado

    SciTech Connect

    Gunawan, I.; Giardino, J.R.; Tchakerian, V.P. . Geography Dept.)

    1992-01-01

    Telluride, located in the San Juan mountains of southwestern Colorado, is situated in a glacially carved, fluvially modified alpine valley. Today this chic setting is experiencing rapid urban development resulting from flourishing tourist traffic during both the winter ski season and the summer vacation period. A new development, Mountain Village, is being built on an extensive and complex landslide that has only received superficial scrutiny. Recent fast growth is placing considerable pressure on pristine, undeveloped land. This timely quandary incorporates the interaction between prospective development, geomorphic processes, engineering factors, economic feasibility, and landuse adjudication. In an attempt to respond to these issues the State of Colorado enacted Senate Bill 35 (1972) and House Bills 1034 (1974) and 1041 (1974), all mandating assessment of the natural hazards of an area, preparatory to development. The key to evaluating the natural hazards is to comprehend the geomorphic processes. The area is highly-faulted with associated mineralization. Whereas the upper slopes are composed of massive rhyodacitic-tuff breccias and flows, the valley is sculpted from shales, sandstones, and conglomerates. Several periods of glaciation occurred in the area. Glacial till, talus slopes, avalanche chutes and cones, rock glaciers, alluvium, and landslides have been identified in the field and mapped on aerial photographs. Many of the slopes in the area are active. The authors have constructed a geomorphic map (1:12,500) that shows geology, landforms, geomorphic processes and engineering properties. This map can be used by regulatory agencies in identifying areas of natural hazards potentially sensitive to development.

  9. Preparation and mechanical property of a novel 3D porous magnesium scaffold for bone tissue engineering.

    PubMed

    Zhang, Xue; Li, Xiao-Wu; Li, Ji-Guang; Sun, Xu-Dong

    2014-09-01

    Porous magnesium has been recently recognized as a biodegradable metal for bone substitute applications. A novel porous Mg scaffold with three-dimensional (3D) interconnected pores and with a porosity of 33-54% was produced by the fiber deposition hot pressing (FDHP) technology. The microstructure and morphologies of the porous Mg scaffold were characterized by scanning electron microscopy (SEM), and the effects of porosities on the microstructure and mechanical properties of the porous Mg were investigated. Experimental results indicate that the measured Young's modulus and compressive strength of the Mg scaffold are ranged in 0.10-0.37 GPa, and 11.1-30.3 MPa, respectively, which are fairly comparable to those of cancellous bone. Such a porous Mg scaffold having a 3D interconnected network structure has the potential to be used in bone tissue engineering.

  10. Engineering optical properties of a graphene oxide metamaterial assembled in microfluidic channels.

    PubMed

    Kravets, V G; Marshall, O P; Nair, R R; Thackray, B; Zhukov, A; Leng, J; Grigorenko, A N

    2015-01-26

    The dense packing of two dimensional flakes by van der Waals forces has enabled the creation of new metamaterials with desirable optical properties. Here we assemble graphene oxide sheets into a three dimensional metamaterial using a microfluidic technique and confirm their ordering via measurements of ellipsometric parameters, polarized optical microscopy, polarized transmission spectroscopy, infrared spectroscopy and scanning electron microscopy. We show that the produced metamaterials demonstrate strong in-plane optical anisotropy (Δn≈0.3 at n≈1.5-1.8) combined with low absorption (k<0.1) and compare them with as-synthesized samples of graphene oxide paper. Our results pave the way for engineered birefringent metamaterials on the basis of two dimensional atomic crystals including graphene and its derivatives.

  11. Exploring the Properties of Genetically Engineered Silk-Elastin-Like Protein Films.

    PubMed

    Machado, Raul; da Costa, André; Sencadas, Vitor; Pereira, Ana Margarida; Collins, Tony; Rodríguez-Cabello, José Carlos; Lanceros-Méndez, Senentxu; Casal, Margarida

    2015-12-01

    Free standing films of a genetically engineered silk-elastin-like protein (SELP) were prepared using water and formic acid as solvents. Exposure to methanol-saturated air promoted the formation of aggregated β-strands rendering aqueous insolubility and improved the mechanical properties leading to a 10-fold increase in strain-to-failure. The films were optically clear with resistivity values similar to natural rubber and thermally stable up to 180 °C. Addition of glycerol showed to enhance the flexibility of SELP/glycerol films by interacting with SELP molecules through hydrogen bonding, interpenetrating between the polymer chains and granting more conformational freedom. This detailed characterization provides cues for future and unique applications using SELP based biopolymers.

  12. On the relationship between engineering properties and delamination of composite materials

    NASA Technical Reports Server (NTRS)

    Herakovich, C. T.

    1981-01-01

    Delamination of composite materials has been investigated with emphasis on the relationship between the engineering properties of the individual layers and edge effects. It is shown that interlaminar shear stresses are primarily a function of the mismatch in coefficients of mutual influence which can be as much as ten times greater than the mismatch in Poisson's ratio. The mismatch in coefficients of mutual influence has a high peak value in the 10-15 deg range for plus or minus theta laminates (where theta is the angle of fiber orientation measured from the axis of the coupon). This mismatch is reduced by a factor of two when the plus or minus theta layers are interspersed between 0 and 90 deg layers. Application of the results to composite design is illustrated by an example.

  13. Properties of jet engine combustion particles during the PartEmis experiment: Hygroscopicity at subsaturated conditions

    NASA Astrophysics Data System (ADS)

    Gysel, M.; Nyeki, S.; Weingartner, E.; Baltensperger, U.; Giebl, H.; Hitzenberger, R.; Petzold, A.; Wilson, C. W.

    2003-06-01

    Hygroscopic properties of combustion particles were measured online with a Hygroscopicity Tandem Differential Mobility Analyzer (H-TDMA) during PartEmis jet engine combustor experiments. The combustor was operated at old and modern cruise conditions with fuel sulfur contents (FSC) of 50, 410 and 1270 μg g-1, and hygroscopic growth factors (HGF) of particles with different dry diameters were investigated at relative humidities RH <= 95%. HGFs increased strongly with increasing FSC (HGF[95% RH, 50 nm, modern cruise] = 1.01 and 1.16 for low and high FSC, respectively), and decreased with increasing particle size at fixed FSC, whereas no significant difference was detected between old and modern cruise. HGFs agreed well with a two-parameter theoretical model which provided an estimate of the sulfuric acid content of dry particles, indicating a nearly linear dependence on FSC.

  14. An improved method for estimating in situ stress in an elastic rock mass and its engineering application

    NASA Astrophysics Data System (ADS)

    Pei, Qitao; Ding, Xiuli; Lu, Bo; Zhang, Yuting; Huang, Shuling; Dong, Zhihong

    2016-10-01

    The main contribution of this paper is to develop a method to determine the in situ stress on an engineering scale by modifying the elasto-static thermal stress model (Sheorey's model). The suggested method, firstly, introduces correction factors for the local tectonism to reflect the stress distribution difference caused by local tectonic movements. The correction factors can be determined by the least-squares approach based on laboratory tests and local in situ stress measurements. Then, the rock elastic modulus is replaced by rock mass elastic modulus so as to show the effect of rock discontinuities on the in situ stress. Combining with elasticity theory, equations for estimating the major and minor horizontal stresses are obtained. It is possible to reach satisfactory accuracy for stress estimation. To show the feasibility of this method, it is applied to two deep tunnels in China to determine the in situ stress. Field tests, including in situ stress measurements by conventional hydraulic fracturing (HF) and rock mass modulus measurements using a rigid borehole jack (RBJ), are carried out. It is shown that the stress field in the two deep tunnels is dominated by horizontal tectonic movements. The major and minor horizontal stresses are estimated, respectively. Finally, the results are compared with those derived from the HF method. The calculated results in the two tunnels roughly coincide with the measured results with an average of 15% allowable discrepancy.

  15. Morpheus Spectral Counter: A computational tool for label-free quantitative mass spectrometry using the Morpheus search engine.

    PubMed

    Gemperline, David C; Scalf, Mark; Smith, Lloyd M; Vierstra, Richard D

    2016-03-01

    Label-free quantitative MS based on the Normalized Spectral Abundance Factor (NSAF) has emerged as a straightforward and robust method to determine the relative abundance of individual proteins within complex mixtures. Here, we present Morpheus Spectral Counter (MSpC) as the first computational tool that directly calculates NSAF values from output obtained from Morpheus, a fast, open-source, peptide-MS/MS matching engine compatible with high-resolution accurate-mass instruments. NSAF has distinct advantages over other MS-based quantification methods, including a greater dynamic range as compared to isobaric tags, no requirement to align and re-extract MS1 peaks, and increased speed. MSpC features an easy-to-use graphic user interface that additionally calculates both distributed and unique NSAF values to permit analyses of both protein families and isoforms/proteoforms. MSpC determinations of protein concentration were linear over several orders of magnitude based on the analysis of several high-mass accuracy datasets either obtained from PRIDE or generated with total cell extracts spiked with purified Arabidopsis 20S proteasomes. The MSpC software was developed in C# and is open sourced under a permissive license with the code made available at http://dcgemperline.github.io/Morpheus_SpC/.

  16. Morpheus Spectral Counter: A Computational Tool for Label-Free Quantitative Mass Spectrometry using the Morpheus Search Engine

    PubMed Central

    Gemperline, David C.; Scalf, Mark; Smith, Lloyd M.; Vierstra, Richard D.

    2016-01-01

    Label-free quantitative MS based on the Normalized Spectral Abundance Factor (NSAF) has emerged as a straightforward and robust method to determine the relative abundance of individual proteins within complex mixtures. Here, we present Morpheus Spectral Counter (MSpC) as the first computational tool that directly calculates NSAF values from output obtained from Morpheus, a fast, open-source, peptide-MS/MS matching engine compatible with high-resolution accurate-mass instruments. NSAF has distinct advantages over other MS-based quantification methods, including a higher dynamic range as compared to isobaric tags, no requirement to align and re-extract MS1 peaks, and increased speed. MSpC features an easy to use graphic user interface that additionally calculates both distributed and unique NSAF values to permit analyses of both protein families and isoforms/proteoforms. MSpC determinations of protein concentration were linear over several orders of magnitude based on the analysis of several high-mass accuracy datasets either obtained from PRIDE or generated with total cell extracts spiked with purified Arabidopsis 20S proteasomes. The MSpC software was developed in C# and is open sourced under a permissive license with the code made available at http://dcgemperline.github.io/Morpheus_SpC/. PMID:26791624

  17. Concentration Dependent Speciation and Mass Transport Properties of Switchable Polarity Solvents

    SciTech Connect

    Aaron D. Wilson; Christopher J. Orme

    2014-12-01

    Tertiary amine switchable polarity solvents (SPS) consisting of predominantly water, tertiary amine, and tertiary ammonium and bicarbonate ions were produced at various concentrations for three different amines: N,N-dimethylcyclohexylamine, N,N-dimethyloctylamine, and 1 cyclohexylpiperidine. For all concentrations, physical properties were measured including viscosity, molecular diffusion coefficients, freezing point depression, and density. Based on these measurements a variation on the Mark Houwink equation was developed to predict the viscosity of any tertiary amine SPS as a function of concentration using the amine’s molecular mass. The observed physical properties allowed the identification of solution state speciation of non-osmotic SPS, where the amine to carbonic acid ratio is significantly greater than one. These results indicate that at most concentrations the stoichiometric excess amine is involved in solvating a proton with two amines. The physical properties of osmotic SPS have consistent concentration dependence behavior over a wide range of concentrations; this consistence suggests osmotic pressures based on low concentrations freezing point studies can be reliably extrapolated to higher concentrations.

  18. Structural and fractal properties of particles emitted from spark ignition engines.

    PubMed

    Chakrabarty, Rajan K; Moosmüller, Hans; Arnott, W Patrick; Garro, Mark A; Walker, John

    2006-11-01

    Size, morphology, and microstructure of particles emitted from one light-duty passenger vehicle (Buick Century; model year 1990; PM (particulate matter) mass emission rate 3.1 mg/km) and two light-duty trucks (Chevrolet C2; model year 1973; PM mass emission rate 282 mg/km, and Chevrolet El Camino; model year 1976; PM mass emission rate 31 mg/km), running California's unified driving cycles (UDC) on a chassis dynamometer, were studied using scanning electron microscopy (SEM). SEM images yielded particle properties including three-dimensional density fractal dimensions, monomer and agglomerate number size distributions, and three different shape descriptors, namely aspect ratio, root form factor, and roundness. The density fractal dimension of the particles was between 1.7 and 1.78, while the number size distribution of the particles placed the majority of the particles in the accumulation mode (0.1-0.3 microm). The shape descriptors were found to decrease with increasing particle size. Partial melting of particles, a rare and previously unreported phenomenon, was observed upon exposure of particles emitted during phase 2 of the UDC to the low accelerating voltage electron beam of the SEM. The rate of melting was quantified for individual particles, establishing a near linear relationship between the melting rate and the organic carbon 1 to elemental carbon ratio.

  19. Elastic, permeability and swelling properties of human intervertebral disc tissues: A benchmark for tissue engineering.

    PubMed

    Cortes, Daniel H; Jacobs, Nathan T; DeLucca, John F; Elliott, Dawn M

    2014-06-27

    The aim of functional tissue engineering is to repair and replace tissues that have a biomechanical function, i.e., connective orthopaedic tissues. To do this, it is necessary to have accurate benchmarks for the elastic, permeability, and swelling (i.e., biphasic-swelling) properties of native tissues. However, in the case of the intervertebral disc, the biphasic-swelling properties of individual tissues reported in the literature exhibit great variation and even span several orders of magnitude. This variation is probably caused by differences in the testing protocols and the constitutive models used to analyze the data. Therefore, the objective of this study was to measure the human lumbar disc annulus fibrosus (AF), nucleus pulposus (NP), and cartilaginous endplates (CEP) biphasic-swelling properties using a consistent experimental protocol and analyses. The testing protocol was composed of a swelling period followed by multiple confined compression ramps. To analyze the confined compression data, the tissues were modeled using a biphasic-swelling model, which augments the standard biphasic model through the addition of a deformation-dependent osmotic pressure term. This model allows considering the swelling deformations and the contribution of osmotic pressure in the analysis of the experimental data. The swelling stretch was not different between the disc regions (AF: 1.28±0.16; NP: 1.73±0.74; CEP: 1.29±0.26), with a total average of 1.42. The aggregate modulus (Ha) of the extra-fibrillar matrix was higher in the CEP (390kPa) compared to the NP (100kPa) or AF (30kPa). The permeability was very different across tissue regions, with the AF permeability (64 E(-16)m(4)/Ns) higher than the NP and CEP (~5.5 E(-16)m(4)/Ns). Additionally, a normalized time-constant (3000s) for the stress relaxation was similar for all the disc tissues. The properties measured in this study are important as benchmarks for tissue engineering and for modeling the disc's mechanical

  20. The use of agrobiodiversity for plant improvement and the intellectual property paradigm: institutional fit and legal tools for mass selection, conventional and molecular plant breeding.

    PubMed

    Batur, Fulya; Dedeurwaerdere, Tom

    2014-12-01

    Focused on the impact of stringent intellectual property mechanisms over the uses of plant agricultural biodiversity in crop improvement, the article delves into a systematic analysis of the relationship between institutional paradigms and their technological contexts of application, identified as mass selection, controlled hybridisation, molecular breeding tools and transgenics. While the strong property paradigm has proven effective in the context of major leaps forward in genetic engineering, it faces a systematic breakdown when extended to mass selection, where innovation often displays a collective nature. However, it also creates partial blockages in those innovation schemes rested between on-farm observation and genetic modification, i.e. conventional plant breeding and upstream molecular biology research tools. Neither overly strong intellectual property rights, nor the absence of well delineated protection have proven an optimal fit for these two intermediary socio-technological systems of cumulative incremental innovation. To address these challenges, the authors look at appropriate institutional alternatives which can create effective incentives for in situ agrobiodiversity conservation and the equitable distribution of technologies in plant improvement, using the flexibilities of the TRIPS Agreement, the liability rules set forth in patents or plant variety rights themselves (in the form of farmers', breeders' and research exceptions), and other ad hoc reward regimes.

  1. Biaxial Stretch Improves Elastic Fiber Maturation, Collagen Arrangement, and Mechanical Properties in Engineered Arteries.

    PubMed

    Huang, Angela H; Balestrini, Jenna L; Udelsman, Brooks V; Zhou, Kevin C; Zhao, Liping; Ferruzzi, Jacopo; Starcher, Barry C; Levene, Michael J; Humphrey, Jay D; Niklason, Laura E

    2016-06-01

    Tissue-engineered blood vessels (TEVs) are typically produced using the pulsatile, uniaxial circumferential stretch to mechanically condition and strengthen the arterial grafts. Despite improvements in the mechanical integrity of TEVs after uniaxial conditioning, these tissues fail to achieve critical properties of native arteries such as matrix content, collagen fiber orientation, and mechanical strength. As a result, uniaxially loaded TEVs can result in mechanical failure, thrombus, or stenosis on implantation. In planar tissue equivalents such as artificial skin, biaxial loading has been shown to improve matrix production and mechanical properties. To date however, multiaxial loading has not been examined as a means to improve mechanical and biochemical properties of TEVs during culture. Therefore, we developed a novel bioreactor that utilizes both circumferential and axial stretch that more closely simulates loading conditions in native arteries, and we examined the suture strength, matrix production, fiber orientation, and cell proliferation. After 3 months of biaxial loading, TEVs developed a formation of mature elastic fibers that consisted of elastin cores and microfibril sheaths. Furthermore, the distinctive features of collagen undulation and crimp in the biaxial TEVs were absent in both uniaxial and static TEVs. Relative to the uniaxially loaded TEVs, tissues that underwent biaxial loading remodeled and realigned collagen fibers toward a more physiologic, native-like organization. The biaxial TEVs also showed increased mechanical strength (suture retention load of 303 ± 14.53 g, with a wall thickness of 0.76 ± 0.028 mm) and increased compliance. The increase in compliance was due to combinatorial effects of mature elastic fibers, undulated collagen fibers, and collagen matrix orientation. In conclusion, biaxial stretching is a potential means to regenerate TEVs with improved matrix production, collagen organization, and mechanical

  2. Development of the mechanical properties of engineered skin substitutes after grafting to full-thickness wounds.

    PubMed

    Sander, Edward A; Lynch, Kaari A; Boyce, Steven T

    2014-05-01

    Engineered skin substitutes (ESSs) have been reported to close full-thickness burn wounds but are subject to loss from mechanical shear due to their deficiencies in tensile strength and elasticity. Hypothetically, if the mechanical properties of ESS matched those of native skin, losses due to shear or fracture could be reduced. To consider modifications of the composition of ESS to improve homology with native skin, biomechanical analyses of the current composition of ESS were performed. ESSs consist of a degradable biopolymer scaffold of type I collagen and chondroitin-sulfate (CGS) that is populated sequentially with cultured human dermal fibroblasts (hF) and epidermal keratinocytes (hK). In the current study, the hydrated biopolymer scaffold (CGS), the scaffold populated with hF dermal skin substitute (DSS), or the complete ESS were evaluated mechanically for linear stiffness (N/mm), ultimate tensile load at failure (N), maximum extension at failure (mm), and energy absorbed up to the point of failure (N-mm). These biomechanical end points were also used to evaluate ESS at six weeks after grafting to full-thickness skin wounds in athymic mice and compared to murine autograft or excised murine skin. The data showed statistically significant differences (p <0.05) between ESS in vitro and after grafting for all four structural properties. Grafted ESS differed statistically from murine autograft with respect to maximum extension at failure, and from intact murine skin with respect to linear stiffness and maximum extension. These results demonstrate rapid changes in mechanical properties of ESS after grafting that are comparable to murine autograft. These values provide instruction for improvement of the biomechanical properties of ESS in vitro that may reduce clinical morbidity from graft loss.

  3. NextSearch: A Search Engine for Mass Spectrometry Data against a Compact Nucleotide Exon Graph.

    PubMed

    Kim, Hyunwoo; Park, Heejin; Paek, Eunok

    2015-07-02

    Proteogenomics research has been using six-frame translation of the whole genome or amino acid exon graphs to overcome the limitations of reference protein sequence database; however, six-frame translation is not suitable for annotating genes that span over multiple exons, and amino acid exon graphs are not convenient to represent novel splice variants and exon skipping events between exons of incompatible reading frames. We propose a proteogenomic pipeline NextSearch (Nucleotide EXon-graph Transcriptome Search) that is based on a nucleotide exon graph. This pipeline consists of constructing a compact nucleotide exon graph that systematically incorporates novel splice variations and a search tool that identifies peptides by directly searching the nucleotide exon graph against tandem mass spectra. Because our exon graph stores nucleotide sequences, it can easily represent novel splice variations and exon skipping events between incompatible reading frame exons. Searching for peptide identification is performed against this nucleotide exon graph, without converting it into a protein sequence in FASTA format, achieving an order of magnitude reduction in the size of the sequence database storage. NextSearch outputs the proteome-genome/transcriptome mapping results in a general feature format (GFF) file, which can be visualized by public tools such as the UCSC Genome Browser.

  4. A fast sampling device for the mass spectrometric analysis of liquid rocket engine exhaust

    NASA Technical Reports Server (NTRS)

    Ryason, P. R.

    1975-01-01

    The design of a device to obtain compositional data on rocket exhaust by direct sampling of reactive flow exhausts into a mass spectrometer is presented. Sampling at three stages differing in pressure and orifice angle and diameter is possible. Results of calibration with pure gases and gas mixtures are erratic and of unknown accuracy for H2, limiting the usefulness of the apparatus for determining oxidizer/fuel ratios from combustion product analysis. Deposition effects are discussed, and data obtained from rocket exhaust spectra are analyzed to give O/F ratios and mixture ratio distribution. The O/F ratio determined spectrometrically is insufficiently accurate for quantitative comparison with cold flow data. However, a criterion for operating conditions with improved mixing of fuel and oxidizer which is consistent with cold flow results may be obtained by inspection of contour plots. A chemical inefficiency in the combustion process when oxidizer is in excess is observed from reactive flow measurements. Present results were obtained with N2O4/N2H4 propellants.

  5. PHYSICAL PROPERTIES OF THE LOW-MASS ECLIPSING BINARY NSVS 02502726

    SciTech Connect

    Lee, Jae Woo; Youn, Jae-Hyuck; Kim, Seung-Lee; Lee, Chung-Uk E-mail: jhyoon@kasi.re.kr E-mail: leecu@kasi.re.kr

    2013-01-01

    NSVS 02502726 has been known as a double-lined, detached eclipsing binary that consists of two low-mass stars. We obtained BVRI photometric follow-up observations in 2009 and 2011 to measure improved physical properties of the binary star. Each set of light curves, including the 2008 data given by Cakirli et al., was simultaneously analyzed with the previously published radial velocity curves using the Wilson-Devinney binary code. The conspicuous seasonal light variations of the system are satisfactorily modeled by a two-spot model with one starspot on each component and by changes of the spot parameters with time. Based on 23 eclipse timings calculated from the synthetic model and one ephemeris epoch, an orbital period study of NSVS 02502726 reveals that the period has experienced a continuous decrease of -5.9 Multiplication-Sign 10{sup -7} day yr{sup -1} or a sinusoidal variation with a period and semi-amplitude of 2.51 yr and 0.0011 days, respectively. The timing variations could be interpreted as either the light-travel-time effect due to the presence of an unseen third body, or as the combination of this effect and angular momentum loss via magnetic stellar wind braking. Individual masses and radii of both components are determined to be M{sub 1} = 0.689 {+-} 0.016 M{sub Sun }, M{sub 2} = 0.341 {+-} 0.009 M{sub Sun }, R{sub 1} = 0.707 {+-} 0.007 R{sub Sun }, and R{sub 2} = 0.657 {+-} 0.008 R{sub Sun }. The results are very different from those of Cakirli et al. with the primary's radius (0.674 {+-} 0.006 R{sub Sun }) smaller the secondary's (0.763 {+-} 0.007 R{sub Sun }). We compared the physical parameters presented in this paper with current low-mass stellar models and found that the measured values of the primary star are best fitted to a 79 Myr isochrone. The primary is in good agreement with the empirical mass-radius relation from low-mass binaries, but the secondary is oversized by about 85%.

  6. Ground state properties of electron-hole bilayer: Mass-asymmetric effect

    NASA Astrophysics Data System (ADS)

    Sharma, R. O.; Saini, L. K.; Bahuguna, Bhagwati Prasad

    2016-11-01

    We study the effects of mass asymmetry on the ground state properties of an electron-hole bilayer (EHBL) system at T =0 by using the quantum Monte Carlo method. Particularly, we use the variational Monte Carlo method to calculate the pair-correlation function g (r ) and the condensation fraction c at a fixed density for different values of interplaner distance d and extract the phases of the EHBL system. We use a single trial wave function that can describe fluid, excitonic, and biexcitonic phases. We find that the excitonic fluid phase is stable in the region of d ≥0.25 a .u . and a transition from the excitonic fluid phase to the biexcitonic fluid phase at d =0.24 a .u .

  7. Monitoring of Water Masses Properties in the Channel of Sardinia by Glider and Satellites Observations

    NASA Astrophysics Data System (ADS)

    Gana, Slim; Iudicone, Daniele; Ghenim, Leila; Mortier, Laurent; Testor, Pierre; Olita, Antonio; Buongiono-Nardelli, Bruno; Tintore, Joaquin

    2015-12-01

    In the framework of the EC funded project, PERSEUS (Subtask 3.3.1: Repeated glider sections in key channels and sub-basin) and with the support of JERICO TNA (EU-FP7), a deep water glider (up to 1000m) was deployed from the R/V Tethys in the Sardinia Channel and has carried out 3 return trips during the period from the 16th of August 2014 to the 19th of September 2014. The Gilder was programmed to follow a path close to SARAL satellite track #887. In this paper, after an overview of the hydrological properties of the water masses in the area highlighted by the glider data, we are focusing on a joint analysis of in-situ and satellite data to understand the behavior of a cyclonic eddy observed in the area.

  8. Thermal properties of holmium-implanted gold films for a neutrino mass experiment with cryogenic microcalorimeters

    SciTech Connect

    Prasai, K.; Yanardag, S. Basak; Galeazzi, M.; Uprety, Y.; Alves, E.; Rocha, J.; Bagliani, D.; Biasotti, M.; Gatti, F.; Gomes, M. Ribeiro

    2013-08-15

    In a microcalorimetric neutrino mass experiment using the radioactive decay of {sup 163}Ho, the radioactive material must be fully embedded in the microcalorimeter absorber. One option that is being investigated is to implant the radioactive isotope into a gold absorber, as gold is successfully used in other applications. However, knowing the thermal properties at the working temperature of microcalorimeters is critical for choosing the absorber material and for optimizing the detector performance. In particular, it is paramount to understand if implanting the radioactive material in gold changes its heat capacity. We used a bolometric technique to measure the heat capacity of gold films, implanted with various concentrations of holmium and erbium (a byproduct of the {sup 163}Ho fabrication), in the temperature range 70 mK–300 mK. Our results show that the specific heat capacity of the gold films is not affected by the implant, making this a viable option for a future microcalorimeter holmium experiment.

  9. Upgrade of the Goddard Space Flight Center's Mass Properties Measuring Facility

    NASA Technical Reports Server (NTRS)

    Ross, Brian P.; McLeod, Christopher

    2004-01-01

    Goddard Space Flight Center has a Mass Properties Measuring Facility (MPMF), which is used to measure weight, center of gravity, moment of inertia, and product of inertia of satellites and space flight hardware. The system was originally purchased more than 30 years ago. While the MPMF was still in good mechanical condition, the measurement and control subsystem had begun to experience more frequent component failures. Many of the outdated, discrete components in the system are no longer available for replacement. A decision was made to upgrade the measurement and control subsystem of the MPMF to improve its reliability and reduce the chance of component failures leading to extended facility outages. This paper will describe details of the upgraded subsystems and summarize the new performance capabilities of the system.

  10. Arginine deiminase: recent advances in discovery, crystal structure, and protein engineering for improved properties as an anti-tumor drug.

    PubMed

    Han, Rui-Zhi; Xu, Guo-Chao; Dong, Jin-Jun; Ni, Ye

    2016-06-01

    Arginine deiminase (ADI) is an important arginine-degrading enzyme with wide applications, in particular as an anti-cancer agent for the therapy of arginine-auxotrophic tumors. In recent years, novel ADIs with excellent properties have been identified from various organisms, and crystal structures of ADI were investigated. To satisfy the requirements of potential therapeutic applications, protein engineering has been performed to improve the activity and properties of ADIs. In this mini-review, we systematically summarized the latest progress on identification and crystal structure of ADIs, and protein engineering strategies for improved enzymatic properties, such as pH optimum, K m and k cat values, and thermostability. We also outlined the PEGylation of ADI for improved circulating half-life and immunogenicity, as well as their performance in clinical trials. Finally, perspectives on extracellular secretion and property improvement of ADI were discussed.

  11. Characterizing the viscoelastic properties of thin hydrogel-based constructs for tissue engineering applications.

    PubMed

    Ahearne, Mark; Yang, Ying; El Haj, Alicia J; Then, Kong Y; Liu, Kuo-Kang

    2005-12-22

    We present a novel indentation method for characterizing the viscoelastic properties of alginate and agarose hydrogel based constructs, which are often used as a model system of soft biological tissues. A sensitive long working distance microscope was used for measuring the time-dependent deformation of the thin circular hydrogel membranes under a constant load. The deformation of the constructs was measured laterally. The elastic modulus as a function of time can be determined by a large deformation theory based on Mooney-Rivlin elasticity. A viscoelastic theory, Zener model, was applied to correlate the time-dependent deformation of the constructs with various gel concentrations, and the creep parameters can therefore be quantitatively estimated. The value of Young's modulus was shown to increase in proportion with gel concentration. This finding is consistent with other publications. Our results also showed the great capability of using the technique to measure gels with incorporated corneal stromal cells. This study demonstrates a novel and convenient technique to measure mechanical properties of hydrogel in a non-destructive, online and real-time fashion. Thus this novel technique can become a valuable tool for soft tissue engineering.

  12. Dynamic control over cell adhesive properties using molecular-based surface engineering strategies.

    PubMed

    Robertus, Jort; Browne, Wesley R; Feringa, Ben L

    2010-01-01

    In complex organisms, cells are often dependent on their extracellular matrix (ECM) for structural integrity, the mechanical properties of tissues, and for signaled regulation of cellular processes including adhesion, migration, growth, secretion, gene expression and apoptosis. Achieving dynamic control, i.e. by using an external stimulus, over the interactions between cells and artificial interfaces holds considerable promise in tissue engineering, medicine, cell biology and immunology. For example, improved spatial control over cell-surface interaction is potentially useful in the design of cell-based screening devices. Dynamic control over SAMs for cell adhesion provides an additional handle to direct and study the attachment of cells to surfaces, e.g., in studying cell spreading from a predetermined pattern in order to screen the cytotoxicity of drug candidates. However, 'reversible' control of cell adhesion onto substrates is an area that is still in its infancy. In this critical review recent developments in cell adhesion of mammalian cells to SAM-modified surfaces, the physical properties of which can be controlled by an external stimulus, e.g. by light, electrochemistry, etc., are discussed (118 references).

  13. Engineering and Probing Topological Properties of Dirac Semimetal Films by Asymmetric Charge Transfer.

    PubMed

    Villanova, John W; Barnes, Edwin; Park, Kyungwha

    2017-02-08

    Dirac semimetals (DSMs) have topologically robust three-dimensional Dirac (doubled Weyl) nodes with Fermi-arc states. In heterostructures involving DSMs, charge transfer occurs at the interfaces, which can be used to probe and control their bulk and surface topological properties through surface-bulk connectivity. Here we demonstrate that despite a band gap in DSM films, asymmetric charge transfer at the surface enables one to accurately identify locations of the Dirac-node projections from gapless band crossings and to examine and engineer properties of the topological Fermi-arc surface states connecting the projections, by simulating adatom-adsorbed DSM films using a first-principles method with an effective model. The positions of the Dirac-node projections are insensitive to charge transfer amount or slab thickness except for extremely thin films. By varying the amount of charge transfer, unique spin textures near the projections and a separation between the Fermi-arc states change, which can be observed by gating without adatoms.

  14. Defect Engineering of Lead-Free Piezoelectrics with High Piezoelectric Properties and Temperature-Stability.

    PubMed

    Feng, Yu; Li, Wei-Li; Xu, Dan; Qiao, Yu-Long; Yu, Yang; Zhao, Yu; Fei, Wei-Dong

    2016-04-13

    The high piezoelectricity of ABO3-type lead-free piezoelectric materials can be achieved with the help of either morphotropic phase boundary (MPB) or polymorphic phase transition (PPT). Here, we propose a new defect engineering route to the excellent piezoelectric properties, in which doped smaller acceptor and donor ions substituting bivalent A-sites are utilized to bring local lattice distortion and lower symmetry. A concrete paradigm is presented, (Li-Al) codoped BaTiO3 perovskite, that exhibits a largely thermo-stable piezoelectric constant (>300 pC/N) and huge mechanical quality factor (>2000). A systematic analysis including theoretical analysis and simulation results indicates that the Li(+) and Al(3+) ions are inclined to occupy the neighboring A-sites in the lattice and constitute a defect dipole (ionic pairs). The defect dipoles possess a kind of dipole moment which tends to align directionally after thermo-electric treatment. A mechanism related to the defect symmetry principle, phase transition, and defect migration is proposed to explain the outstanding piezoelectric properties. The present study opens a new development window for excellent piezoelectricity and provides a promising route to the potential utilization of lead-free piezoelectrics in high power applications.

  15. Laser engineered net shaping (LENS{trademark}) process: Optimization of surface finish and microstructural properties

    SciTech Connect

    Smugeresky, J.E.; Keicher, D.M.; Romero, J.A.; Griffith, M.L.; Harwell, L.D.

    1997-11-01

    Rapid prototyping (RP) has revolutionized the approach to fabricating geometrically complex hardware from a CAD solid model. The various RP techniques allow component designers to directly fabricate conceptual models in plastics and polymer coated metals; however, each of the techniques requires additional processes, e.g. investment casting, to allow the fabrication of functional metallic hardware. This limitation has provided the impetus for further development of solid freeform fabrication technologies which enable fabrication of functional metallic hardware directly from the CAD solid model. The Laser Engineered Net Shaping (LENS{trademark}) process holds promise in satisfying this need. This newly emerging technology possesses the capability to fabricate fully dense components with good dimensional accuracy and with unique materials properties. Relatively complex geometrical shapes have been fabricated using this technology. In continuing to develop the LENS{trademark} process, further advancements are required. The functional dependence of the component surface finish and microstructural characteristics on process parameters including power size and size distribution are being evaluated. A set of statistically designed experiments is being used to sort through the various process parameters and identify significant process variables for improving surface finish and achieving optimum material microstructural properties.

  16. Chemical and engineering properties of fired bricks containing 50 weight percent of class F fly ash

    USGS Publications Warehouse

    Chou, I.-Ming; Patel, V.; Laird, C.J.; Ho, K.K.

    2001-01-01

    The generation of fly ash during coal combustion represents a considerable solid waste disposal problem in the state of Illinois and nationwide. In fact, the majority of the three million tons of fly ash produced from burning Illinois bituminous coals is disposed of in landfills. The purpose of this study was to obtain a preliminary assessment of the technical feasibility of mitigating this solid waste problem by making fired bricks with the large volume of fly ash generated from burning Illinois coals. Test bricks were produced by the extrusion method with increasing amounts (20-50% by weight) of fly ash as a replacement for conventional raw materials. The chemical characteristics and engineering properties of the test bricks produced with and without 50 wt% of fly ash substitutions were analyzed and compared. The properties of the test bricks containing fly ash were at least comparable to, if not better than, those of standard test bricks made without fly ash and met the commercial specifications for fired bricks. The positive results of this study suggest that further study on test bricks with fly ash substitutions of greater than 50wt% is warranted. Successful results could have an important impact in reducing the waste disposal problem related to class F fly ash while providing the brick industry with a new low cost raw material. Copyright ?? 2001 Taylor & Francis.

  17. Shape Engineered InAs Quantum Dots with Stabilized Electronic Properties

    NASA Astrophysics Data System (ADS)

    Tokranov, Vadim E.; Yakimov, Michael; Katsnelson, Alex; Lamberti, Matthew; Oktyabrsky, Serge

    2003-07-01

    We have studied the influence of overgrowth procedure and a few monolayer-thick AlAs capping layers on the properties of self-assembled InAs quantum dots (QDs) using transmission electron microscopy (TEM), scanning electron microscopy, and photoluminescence (PL). PL spectroscopy was used to study and optimize optical properties of the QDs by shape engineering (QD truncation) through adjustment of the thickness of overlayers and temperature of the subsequent heating. QDs with 6 nm-thick overlayer with heating step at 560°C was found to have the highest PL intensity at room temperature and the lowest FWHM, 29 meV. Ground state energy of the truncated QDs is very stable against variations of growth parameters. TEM measurements show that the capping AlAs layer covers the QDs entirely even though the dots are truncated by the heating step. 1.22 μm edge-emitting laser with triple-layer truncated QD gain medium demonstrated room temperature minimum threshold current density, 56 A/cm2, and high saturated modal gain, 16 cm-1. Extremely high characteristic temperature, To = 304 K in the 20 - 60°C interval, and maximum lasing temperature of 219°C were measured for this laser diode.

  18. Integrating-Sphere Measurements for Determining Optical Properties of Tissue-Engineered Oral Mucosa

    NASA Astrophysics Data System (ADS)

    Ionescu, A. M.; Cardona, J. C.; Garzón, I.; Oliveira, A. C.; Ghinea, R.; Alaminos, M.; Pérez, M. M.

    2015-02-01

    Surgical procedures carried out in the oral and maxillofacial region can result in large tissue defects. Accounting for the shortage of oral mucosa to replace the excised tissues, different models of an organotypic substitute of the oral mucosa generated by tissue engineering have recently been proposed. In this work, the propagation of light radiation through artificial human oral mucosa substitutes based on fibrin-agarose scaffolds (fibrin, fibrin-0.1% agarose, fibrin-0.2%agarose) is investigated, and their optical properties are determined using the inverse adding-doubling (IAD) method based on integrating-sphere measurements. Similar values for the absorption and scattering coefficients between the fibrin and fibrin-0.1% agarose bioengineered tissues and the native oral mucosa were found. These results suggest the adequacy of these biomaterials for potential clinical use in human oral mucosa applications. These optical properties represent useful references and data for applications requiring the knowledge of the light transport through this type of tissues, applications used in clinical practice. It also provides a new method of information analysis for the quality control of the development of the artificial nanostructured oral mucosa substitutes and its comparison with native oral mucosa tissues.

  19. Particle Engineering of Excipients for Direct Compression: Understanding the Role of Material Properties.

    PubMed

    Mangal, Sharad; Meiser, Felix; Morton, David; Larson, Ian

    2015-01-01

    Tablets represent the preferred and most commonly dispensed pharmaceutical dosage form for administering active pharmaceutical ingredients (APIs). Minimizing the cost of goods and improving manufacturing output efficiency has motivated companies to use direct compression as a preferred method of tablet manufacturing. Excipients dictate the success of direct compression, notably by optimizing powder formulation compactability and flow, thus there has been a surge in creating excipients specifically designed to meet these needs for direct compression. Greater scientific understanding of tablet manufacturing coupled with effective application of the principles of material science and particle engineering has resulted in a number of improved direct compression excipients. Despite this, significant practical disadvantages of direct compression remain relative to granulation, and this is partly due to the limitations of direct compression excipients. For instance, in formulating high-dose APIs, a much higher level of excipient is required relative to wet or dry granulation and so tablets are much bigger. Creating excipients to enable direct compression of high-dose APIs requires the knowledge of the relationship between fundamental material properties and excipient functionalities. In this paper, we review the current understanding of the relationship between fundamental material properties and excipient functionality for direct compression.

  20. Statistical properties of excited nuclei in the mass range 47 ⩽ A ⩽ 59

    NASA Astrophysics Data System (ADS)

    Zhuravlev, B. V.; Lychagin, A. A.; Titarenko, N. N.; Demenkov, V. G.; Trykova, V. I.

    2012-09-01

    Level densities and their energy dependences for nuclei in the mass range of 47 ≤ A ≤ 59 were determined from the results obtained by measuring neutron-evaporation spectra in respective ( p, n) reactions. The spectra of neutrons originating from the ( p, n) reactions on 47Ti, 48Ti, 49Ti, 53Cr, 54Cr, 57Fe, and 59Co nuclei were measured in the proton-energy range of 7-11 MeV. These measurements were performed with the aid of a fast-neutron spectrometer by the time-of-flight method over the base of the EGP-15 pulsed tandem accelerator installed at the Institute for Physics and Power Engineering (Obninsk, Russia). A high resolution of the spectrometer and its stability in the time of flight made it possible to identify reliably discrete low-lying levels along with the continuum part of neutron spectra. Our measured data were analyzed within the statistical equilibrium and preequilibrium models of nuclear reactions. The respective calculations were performed with the aid of the Hauser-Feshbach formalismof statistical theory supplemented with the generalized model of a superfluid nucleus, the back-shifted Fermi gas model, and the Gilbert-Cameron composite formula for nuclear level densities. Nuclear level densities for 47V, 48V, 49V, 53Mn, 54Mn, 57Co, and 59Ni and their energy dependences were determined. The results are discussed and compared with available experimental data and with recommendations of model-based systematics.

  1. Multi-wavelength properties and SMBH's masses of the isolated AGNs in the Local Universe

    NASA Astrophysics Data System (ADS)

    Vavilova, I. B.; Vasylenko, A. A.; Babyk, Iu. V.; Pulatova, N. G.

    2016-08-01

    The sample of 36 nearest isolated AGNs was cross-matched by 2MIG and Veron-Cetty catalogues and limited to Ks ≤ 12.0m and Vr < 15 000 km/s in the northern sky (δ ≥ -15°). These objects were in isolation during ~ 3 Gyrs. For revealing their multi-wavelength properties we used all the available databases obtained with ground-based and space observatories (from radio to X-ray ranges). It is allowed us to separate the internal evolution mechanisms from the environment influence and consider them as two separate processes related to fueling nuclear activity and accretion on the SMBHs outside of the environment. In this report we present briefly main results, which were already published (Pulatova N., Vavilova I., Sawangwit U. et al. The 2MIG isolated AGNs - I. General and multiwavelength properties of AGNs and host galaxies in the northern sky, MNRAS, 447, Issue 3, p. 2209-2223 (2015)). We accentuate that for the first time we revealed that the host isolated galaxies with AGNs of Sy1 type (without faint companions) appear to possess the bar morphological features (e.g., the interaction with neighboring galaxies is not necessary condition for broad-line region formation). We give also current results as concerns with more detail X-ray analysis, emission features and spectral models for several AGNs for which a cumulative soft and hard energy spectrum was reconstructed. The estimates of SMBH masses show that are systematically lower than the SMBH masses of AGNs located in a dense environment.

  2. The influence of body mass index and gender on the impact attenuation properties of flooring systems.

    PubMed

    Bhan, Shivam; Levine, Iris; Laing, Andrew C

    2013-12-01

    The biomechanical effectiveness of safety floors has never been assessed during sideways falls with human volunteers. Furthermore, the influence of body mass index (BMI) and gender on the protective capacity of safety floors is unknown. The purpose of this study was to test whether safety floors provide greater impact attenuation compared with traditional flooring, and whether BMI and gender modify their impact attenuation properties. Thirty participants (7 men and 7 women of low BMI; 7 men and 9 women of high BMI) underwent lateral pelvis release trials on 2 common floors and 4 safety floors. As a group, the safety floors reduced peak force (by up to 11.7%), and increased the time to peak force (by up to 25.5%) compared with a traditional institutional grade floor. Force attenuation was significantly higher for the low BMI group, and for males. Force attenuation was greatest for the low BMI males, averaging 26.5% (SD = 3.0) across the safety floors. These findings demonstrate an overall protective effect of safety floors during lateral falls on the pelvis, but also suggest augmented benefits for frail older adults (often with low body mass) who are at an increased risk of hip fracture.

  3. Reflectivity properties of graphene with a nonzero mass-gap parameter

    NASA Astrophysics Data System (ADS)

    Klimchitskaya, G. L.; Mostepanenko, V. M.

    2016-05-01

    The reflectivity properties of graphene with a nonzero mass-gap parameter are investigated in the framework of a Dirac model using the polarization tensor in (2 +1 ) -dimensional space-time. For this purpose, a more simple explicit representation for the polarization tensor along the real frequency axis is found. The approximate analytic expressions for the polarization tensor and for the reflectivities of graphene are obtained in different frequency regions at any temperature. We show that the nonzero mass-gap parameter has a profound effect on the reflectivity of graphene. Specifically, at zero temperature the reflectivity of gapped graphene goes to zero with vanishing frequency. At nonzero temperature the same reflectivities are equal to unity at zero frequency. We also find the resonance behavior of the reflectivities of gapped graphene at both zero and nonzero temperature at the border frequency determined by the width of the gap. At nonzero temperature the reflectivities of graphene drop to zero in the vicinity of some frequency smaller than the border frequency. Our analytic results are accompanied with numerical computations performed over a wide frequency region. The developed formalism can be used in devising nanoscale optical detectors and optoelectronic switches and in other optical applications of graphene.

  4. Galaxy and mass assembly (GAMA): Mid-infrared properties and empirical relations from WISE

    SciTech Connect

    Cluver, M. E.; Jarrett, T. H.; Hopkins, A. M.; Gunawardhana, M. L. P.; Bauer, A. E.; Lara-López, M. A.; Driver, S. P.; Robotham, A. S. G.; Liske, J.; Taylor, E. N.; Alpaslan, M.; Baldry, I.; Brown, M. J. I.; Peacock, J. A.; Popescu, C. C.; Tuffs, R. J.; Bland-Hawthorn, J.; Colless, M.; Holwerda, B. W.; Leschinski, K.; and others

    2014-02-20

    The Galaxy And Mass Assembly (GAMA) survey furnishes a deep redshift catalog that, when combined with the Wide-field Infrared Survey Explorer (WISE), allows us to explore for the first time the mid-infrared properties of >110, 000 galaxies over 120 deg{sup 2} to z ≅ 0.5. In this paper we detail the procedure for producing the matched GAMA-WISE catalog for the G12 and G15 fields, in particular characterizing and measuring resolved sources; the complete catalogs for all three GAMA equatorial fields will be made available through the GAMA public releases. The wealth of multiwavelength photometry and optical spectroscopy allows us to explore empirical relations between optically determined stellar mass (derived from synthetic stellar population models) and 3.4 μm and 4.6 μm WISE measurements. Similarly dust-corrected Hα-derived star formation rates can be compared to 12 μm and 22 μm luminosities to quantify correlations that can be applied to large samples to z < 0.5. To illustrate the applications of these relations, we use the 12 μm star formation prescription to investigate the behavior of specific star formation within the GAMA-WISE sample and underscore the ability of WISE to detect star-forming systems at z ∼ 0.5. Within galaxy groups (determined by a sophisticated friends-of-friends scheme), results suggest that galaxies with a neighbor within 100 h {sup –1} kpc have, on average, lower specific star formation rates than typical GAMA galaxies with the same stellar mass.

  5. Engineering excitonic properties and valley polarization in transition metal dichalcogenide monolayers

    NASA Astrophysics Data System (ADS)

    Urbaszek, Bernhard

    Binary Transition metal dichalcogenide (TMDC) monolayer (ML) materials MoS2, MoSe2, WSe2, WS2 and MoTe2 share common properties such as a direct optical bandgap, Spin-Orbit splittings of hundreds of meV and coupled spin-valley states. Optical absorption and emission are dominated by robust excitons, whose resonances also strongly influence Raman scattering amplitudes and second harmonic generation efficiency. Important differences in opto-electronic properties between these materials depend on whether the exciton ground state is optically bright or dark. This order will depend on the conduction band Spin-Orbit splitting and the electron-hole Coulomb interaction and will have strong influence on the light emission yield of the TMDC MLs. In this talk we discuss Spin-Orbit engineering in Mo(1-x)W(x)Se2 alloy monolayers. We probe the impact of the tuning of the conduction band Spin-Orbit spin splitting on the bright versus dark exciton population. For MoSe2 monolayers the PL intensity decreases as a function of temperature by an order of magnitude (T=4-300 K), whereas for WSe2 we measure surprisingly an order of magnitude increase. The ternary material shows a trend between these two extreme behaviors. In addition we show a non-linear increase of the optically generated valley polarization as a function of tungsten (W) concentration. Tuning the optical properties in applied external fields will be discussed. We acknowledge funding from ERC Grant No 306719 and ANR MoS2ValleyControl.

  6. Mechanical properties and in vitro behavior of nanofiber-hydrogel composites for tissue engineering applications

    NASA Astrophysics Data System (ADS)

    Kai, Dan; Prabhakaran, Molamma P.; Stahl, Benjamin; Eblenkamp, Markus; Wintermantel, Erich; Ramakrishna, Seeram

    2012-03-01

    Hydrogel-based biomaterial systems have great potential for tissue reconstruction by serving as temporary scaffolds and cell delivery vehicles for tissue engineering (TE). Hydrogels have poor mechanical properties and their rapid degradation limits the development and application of hydrogels in TE. In this study, nanofiber reinforced composite hydrogels were fabricated by incorporating electrospun poly(ɛ-caprolactone) (PCL)/gelatin ‘blend’ or ‘coaxial’ nanofibers into gelatin hydrogels. The morphological, mechanical, swelling and biodegradation properties of the nanocomposite hydrogels were evaluated and the results indicated that the moduli and compressive strengths of the nanofiber reinforced hydrogels were remarkably higher than those of pure gelatin hydrogels. By increasing the amount of incorporated nanofibers into the hydrogel, the Young’s modulus of the composite hydrogels increased from 3.29 ± 1.02 kPa to 20.30 ± 1.79 kPa, while the strain at break decreased from 66.0 ± 1.1% to 52.0 ± 3.0%. Compared to composite hydrogels with coaxial nanofibers, those with blend nanofibers showed higher compressive strength and strain at break, but with lower modulus and energy dissipation properties. Biocompatibility evaluations of the nanofiber reinforced hydrogels were carried out using bone marrow mesenchymal stem cells (BM-MSCs) by cell proliferation assay and immunostaining analysis. The nanocomposite hydrogel with 25 mg ml-1 PCL/gelatin ‘blend’ nanofibers (PGB25) was found to enhance cell proliferation, indicating that the ‘nanocomposite hydrogels’ might provide the necessary mechanical support and could be promising cell delivery systems for tissue regeneration.

  7. Engineering and functional properties of biodegradable pellets developed from various agro-industrial wastes using extrusion technology.

    PubMed

    Jan, Kulsum; Riar, C S; Saxena, D C

    2015-12-01

    Different agro-industrial wastes were mixed with different plasticizers and extruded to form the pellets to be used further for development of biodegradable molded pots. Bulk density and macro-porosity are the important engineering properties used to determine the functional characteristics of the biodegradable pellets viz., expansion volume, water solubility, product colour, flowability and compactness. Significant differences in the functional properties of pellets with varying bulk densities (loose and tapped) and macro-porosities (loose, tapped) were observed. The observed mean bulk density of biodegradable pellets made from different formulations ranged between 0.213 and 0.560 g/ml for loose fill conditions and 0.248 to 0.604 g/ml for tapped fill conditions. Biodegradable pellets bear a good compaction for both loose and tapped fill methods. The mean macro-porosity of biodegradable pellets ranged between 1.19 and 54.48 % for loose fill condition and 0.29 to 53.35 % for tapped fill condition. Hausner ratio (HR) for biodegradable pellets varied from 1.026 to 1.328, indicating a good flowability of biodegradable pellets. Pearson's correlation between engineering properties and functional properties of biodegradable pellets revealed that from engineering properties functional properties can be predicted.

  8. Identifying the changes of geo-engineering properties of dunites due to weathering utilizing electrical resistivity tomography (ERT)

    NASA Astrophysics Data System (ADS)

    Ündül, Ömer; Tuğrul, Atiye; Özyalın, Şenol; Halil Zarif, İ.

    2015-04-01

    Weathering phenomena have an important role in many construction facilities with varying depths and grades. Due to the anisotropic and heterogeneous nature of weathering profiles of some rocks, uncertainities exist in determining the geo-engineering properties. Geo-electrical studies have been utilized to overcome such uncertainities for various subsurface conditions including the determination of boundaries between weathered and unweathered parts of different rock types. In this study, the electrical resistivity tomography (ERT) results were correlated with conventional methods in determining the effects of weathering on the geo-engineering properties of dunites. During the research, weathering grades were determined by field studies including discontinuity spacings, aperture and properties of fill materials. The detailed petrographical studies, determination of petrophysical properties (e.g. water absorption and effective porosity) and mechanical properties (e.g. unconfined compressive strength (UCS)) constitute the laboratory studies. ERT studies were carried out in a row of sixty electrodes with electrode spacings of 0.5 m utilizing a Wenner-Schlumberger configuration. According to the comparison of the inversion model sections with the weathering profiles obtained by field and laboratory studies it is concluded that the use of ERT with a Wenner-Schlumberger configuration supplies comparable data for wider subsurface areas from the view of weathering and its effect on geo-engineering properties of dunites. In addition, ERT techniques are very useful where conventional techniques are inadequate in determining the full weathering profile.

  9. The impact of air mass advection on aerosol optical properties over Gotland (Baltic Sea)

    NASA Astrophysics Data System (ADS)

    Zdun, Agnieszka; Rozwadowska, Anna; Kratzer, Susanne

    2016-12-01

    In the present paper, measurements of aerosol optical properties from the Gotland station of the AERONET network, combined with a two-stage cluster analysis of back trajectories of air masses moving over Gotland, were used to identify the main paths of air mass advection to the Baltic Sea and to relate them to aerosol optical properties, i.e. the aerosol optical thickness at the wavelength λ = 500 nm, AOT (500) and the Ångström exponent for the spectral range from 440 to 870 nm, α(440,870). One- to six-day long back trajectories ending at 300, 500 and 3000 m above the station were computed using the HYSPLIT model. The study shows that in the Gotland region, variability in aerosol optical thickness AOT(500) is more strongly related to advections in the boundary layer than to those in the free troposphere. The observed variability in AOT(500) was best explained by the advection speeds and directions given by clustering of 4-day backward trajectories of air arriving in the boundary layer at 500 m above the station. 17 clusters of 4-day trajectories arriving at altitude 500 m above the Gotland station (sea level) derived using two-stage cluster analysis differ from each other with respect to trajectory length, the speed of air mass movement and the direction of advection. They also show different cluster means of AOT(500) and α(440,870). The cluster mean AOT(500) ranges from 0.342 ± 0.012 for the continental clusters M2 (east-southeast advection with moderate speed) and 0.294 ± 0.025 for S5 (slow south-southeast advection) to 0.064 ± 0.002 and 0.069 ± 0.002 for the respective marine clusters L3 (fast west-northwest advection) and M3 (north-northwest advection with moderate speed). The cluster mean α(440,870) varies from 1.65-1.70 for the short-trajectory clusters to 0.98 ± 0.03 and 1.06 ± 0.03 for the Arctic marine cluster L4 (fast inflow from the north) and marine cluster L5 (fast inflow from the west) respectively.

  10. A linear control design structure to maintain loop properties during limit operation in a multi-nozzle turbofan engine

    NASA Technical Reports Server (NTRS)

    Mattern, Duane; Ouzts, Peter

    1991-01-01

    The implementation of multi-variable control systems on turbofan engines requires the use of limit protection to maintain safe engine operation. Since a turbofan engine typically encounters limits during transient operation, the use of a limit protection scheme that modifies the feedback loop may void the desired 'guarantees' associated with linear multi-variable control design methods, necessitating considerable simulation to validate the control with limit protection. An alternative control design structure is proposed that maintains the desired linear feedback properties when certain safety limits are encountered by moving the limit protection scheme outside of the feedback loop. This proposed structure is compared to a structure with a limit protection scheme that modifies the feedback loop properties. The two design structures are compared using both linear and nonlinear simulations. The evaluation emphasizes responses where the fan surge margin limit is encountered.

  11. A linear control design structure to maintain loop properties during limit operation in a multi-nozzle turbofan engine

    NASA Technical Reports Server (NTRS)

    Mattern, Duane; Ouzts, Peter

    1991-01-01

    The implementation of multi-variable control systems on turbofan engines requires the use of limit protection to maintain safe engine operation. Since a turbofan engine typically encounters limits during transient operation, the use of a limit protection scheme that modifies the feedback loop may void the desired 'guarantees' associated with linear multi-variable control design methods, necessitating considerable simulation to validate the control with limited protection. An alternative control design structure is proposed that maintains the desired linear feedback properties when certain safety limits are encountered by moving the limit protection scheme outside the feedback loop. This proposed structure is compared to a structure with a limit protection scheme that modifies the feedback loop properties. The two design structures are compared using both linear and nonlinear simulations. The evaluation emphasizes responses where the fan surge margin limit is encountered.

  12. Deflections of Fast Coronal Mass Ejections and the Properties of Associated Solar Energetic Particle Events

    NASA Technical Reports Server (NTRS)

    Kahler, S. W.; Akiyama, S.; Gopalswamy, N.

    2012-01-01

    The onset times and peak intensities of solar energetic particle (SEP) events at Earth have long been thought to be influenced by the open magnetic fields of coronal holes (CHs). The original idea was that a CH lying between the solar SEP source region and the magnetic footpoint of the 1 AU observer would result in a delay in onset and/or a decrease in the peak intensity of that SEP event. Recently, Gopalswamy et al. showed that CHs near coronal mass ejection (CME) source regions can deflect fast CMEs from their expected trajectories in space, explaining the appearance of driverless shocks at 1 AU from CMEs ejected near solar central meridian (CM). This suggests that SEP events originating in CME-driven shocks may show variations attributable to CH deflections of the CME trajectories. Here, we use a CH magnetic force parameter to examine possible effects of CHs on the timing and intensities of 41 observed gradual E approx 20 MeV SEP events with CME source regions within 20 deg. of CM. We find no systematic CH effects on SEP event intensity profiles. Furthermore, we find no correlation between the CME leading-edge measured position angles and SEP event properties, suggesting that the widths of CME-driven shock sources of the SEPs are much larger than the CMEs. Independently of the SEP event properties, we do find evidence for significant CME deflections by CH fields in these events

  13. DEFLECTIONS OF FAST CORONAL MASS EJECTIONS AND THE PROPERTIES OF ASSOCIATED SOLAR ENERGETIC PARTICLE EVENTS

    SciTech Connect

    Kahler, S. W.; Akiyama, S.; Gopalswamy, N.

    2012-08-01

    The onset times and peak intensities of solar energetic particle (SEP) events at Earth have long been thought to be influenced by the open magnetic fields of coronal holes (CHs). The original idea was that a CH lying between the solar SEP source region and the magnetic footpoint of the 1 AU observer would result in a delay in onset and/or a decrease in the peak intensity of that SEP event. Recently, Gopalswamy et al. showed that CHs near coronal mass ejection (CME) source regions can deflect fast CMEs from their expected trajectories in space, explaining the appearance of driverless shocks at 1 AU from CMEs ejected near solar central meridian (CM). This suggests that SEP events originating in CME-driven shocks may show variations attributable to CH deflections of the CME trajectories. Here, we use a CH magnetic force parameter to examine possible effects of CHs on the timing and intensities of 41 observed gradual E {approx} 20 MeV SEP events with CME source regions within 20 Degree-Sign of CM. We find no systematic CH effects on SEP event intensity profiles. Furthermore, we find no correlation between the CME leading-edge measured position angles and SEP event properties, suggesting that the widths of CME-driven shock sources of the SEPs are much larger than the CMEs. Independently of the SEP event properties, we do find evidence for significant CME deflections by CH fields in these events.

  14. Dynamics, kinetics, and transport properties of the one-dimensional mass-disordered harmonic lattice.

    PubMed

    Likhachev, Vladimir N; Vinogradov, George A; Astakhova, Tatyana Yu; Yakovenko, Andrey E

    2006-01-01

    In the present paper we thoroughly investigated the dynamics, kinetics, and the transport properties of the one-dimensional (1D) mass-disordered lattice of harmonic oscillators with the number of particles N < or =5000. The thermostat is simulated by the Langevin sources. Our method is adequate to any 1D lattice with linear equations of motion. Two accurate methods to calculate the temporal behavior of pair correlation functions were developed. The feature of the considered disordered model is an existence of localized states with great relaxation times tau to their stationary states. The exponential growth tau proportional variant exp(N) is observed. A method which allows us to extend the range of computed relaxation times up to tau approximately =(10)300 is suggested. The stationary state is unique. The thermal conduction x has the nonmonotonic character versus N: for the number of particles N < 300 the thermal conduction increases as x proportional variant ln N and reaches the maximal value at N approximately =300. At larger values the decreasing asymptotic is observed: x proportional variant N -alpha, and alpha approximately 0.27. An influence of parameters on the calculated properties was analyzed. Mathematical problems associated with the computation of very large times of establishing the stationary states were extensively studied.

  15. Light-Duty Drive Cycle Simulations of Diesel Engine-Out Exhaust Properties for an RCCI-Enabled Vehicle

    SciTech Connect

    Gao, Zhiming; Curran, Scott; Daw, C Stuart; Wagner, Robert M

    2013-01-01

    In-cylinder blending of gasoline and diesel fuels to achieve low-temperature reactivity controlled compression ignition (RCCI) can reduce NOx and PM emissions while maintaining or improving brake thermal efficiency compared to conventional diesel combustion (CDC). Moreover, the dual-fueling RCCI is able to achieve these benefits by tailoring combustion reactivity over a wider range of engine operation than is possible with a single fuel. However, the currently demonstrated range of stable RCCI combustion just covers a portion of the engine speed-load range required in several light-duty drive cycles. This means that engines must switch from RCCI to CDC when speed and load fall outside of the stable RCCI range. In this study we investigated the impact of RCCI as it has recently been demonstrated on practical engine-out exhaust temperature and emissions by simulating a multi-mode RCCI-enabled vehicle operating over two urban and two highway driving cycles. To implement our simulations, we employed experimental engine maps for a multi-mode RCCI/CDC engine combined with a standard mid-size, automatic transmission, passenger vehicle in the Autonomie vehicle simulation platform. Our results include both detailed transient and cycle-averaged engine exhaust temperature and emissions for each case, and we note the potential implications of the modified exhaust properties on catalytic emissions control and utilization of waste heat recovery on future RCCI-enabled vehicles.

  16. Understanding the structure, dynamics, and mass transport properties of self assembling peptide hydrogels for injectable, drug delivery applications

    NASA Astrophysics Data System (ADS)

    Branco, Monica Cristina

    hydrogels as a function of peptide sequence and concentration. Changes in nanoscale dynamics and structure inherently lead to substantial differences in bulk properties, such as the elastic modulus and network mesh size. Learning how the material properties of the gels influence the transport rate of therapeutics through the hydrogel is essential to the development of delivery vehicles. The remainder of the thesis focuses on correlating the mesh sizes of MAX1 and MAX8 gels to the diffusion and mass transport properties of model dextran and protein probes. Here, work is centered on how peptide charge and concentration, as well as probe structure, in particular hydrodynamic diameter and charge, dictate the temporal release of model probes from the peptide hydrogels. Experiments include self diffusion studies and bulk release experiments with model dextrans and proteins from gels before and after syringe delivery. Overall, this thesis will demonstrate the importance of understanding material properties from the nanoscale up to the macroscale for application based design. With this approach, better and specific development of self-assembling peptide materials can be achieved, allowing for the rational engineering of peptide sequences to form hydrogels appropriate for specific drug delivery applications.

  17. Surface zone articular chondrocytes modulate the bulk and surface mechanical properties of the tissue-engineered cartilage.

    PubMed

    Peng, Gordon; McNary, Sean M; Athanasiou, Kyriacos A; Reddi, A Hari

    2014-12-01

    The central hypothesis of functional tissue engineering is that an engineered construct can serve as a viable replacement tissue in vivo by replicating the structure and function of native tissue. In the case of articular cartilage, this requires the reproduction of the bulk mechanical and surface lubrication properties of native hyaline cartilage. Cartilage tissue engineering has primarily focused on achieving the bulk mechanical properties of native cartilage such as the compressive aggregate modulus and tensile strength. A scaffold-free self-assembling process has been developed that produces engineered cartilage with compressive properties approaching native tissue levels. Thus, the next step in this process is to begin addressing the friction coefficient and wear properties of these engineered constructs. The superficial zone protein (SZP), also known as lubricin or PRG4, is a boundary mode lubricant that is synthesized by surface zone (SZ) articular chondrocytes. Under conditions of high loading and low sliding speeds, SZP reduces friction and wear at the articular surface. The objective of this investigation was to determine whether increasing the proportion of SZ chondrocytes in cartilage constructs, in the absence of external stimuli such as growth factors and mechanical loading, would enhance the secretion of SZP and improve their frictional properties. In this study, cartilage constructs were engineered through a self-assembling process with varying ratios of SZ and middle zone (MZ) chondrocytes (SZ:MZ): 0:100, 25:75, 50:50, 75:25, and 100:0. Constructs containing different ratios of SZ and MZ chondrocytes did not significantly differ in the glycosaminoglycan composition or compressive aggregate modulus. In contrast, tensile properties and collagen content were enhanced in nearly all constructs containing greater amounts of SZ chondrocytes. Increasing the proportion of SZ chondrocytes had the hypothesized effect of improving the synthesis and secretion

  18. Artemis: Results of the engineering feasibility study

    NASA Technical Reports Server (NTRS)

    1991-01-01

    Information is given in viewgraph form for the Engineering Feasibility Study of the Artemis Project, a plan to establish a permanent base on the Moon. Topics covered include the Common Lunar Lander (CLL), lunar lander engineering study results, lunar lander trajectory analysis, lunar lander conceptual design and mass properties, the lunar lander communication subsystem design, and product assurance.

  19. Structural mass irregularities and fiber volume influence on morphology and mechanical properties of unsaturated polyester resin in matrix composites

    PubMed Central

    Ahmed, Khalil; Nasir, Muhammad; Fatima, Nasreen; Khan, Khalid M.; Zahra, Durey N.

    2014-01-01

    This paper presents the comparative results of a current study on unsaturated polyester resin (UPR) matrix composites processed by filament winding method, with cotton spun yarn of different mass irregularities and two different volume fractions. Physical and mechanical properties were measured, namely ultimate stress, stiffness, elongation%. The mechanical properties of the composites increased significantly with the increase in the fiber volume fraction in agreement with the Counto model. Mass irregularities in the yarn structure were quantitatively measured and visualized by scanning electron microscopy (SEM). Mass irregularities cause marked decrease in relative strength about 25% and 33% which increases with fiber volume fraction. Ultimate stress and stiffness increases with fiber volume fraction and is always higher for yarn with less mass irregularities. PMID:26644920

  20. Separation, Sizing, and Quantitation of Engineered Nanoparticles in an Organism Model Using Inductively Coupled Plasma Mass Spectrometry and Image Analysis.

    PubMed

    Johnson, Monique E; Hanna, Shannon K; Montoro Bustos, Antonio R; Sims, Christopher M; Elliott, Lindsay C C; Lingayat, Akshay; Johnston, Adrian C; Nikoobakht, Babak; Elliott, John T; Holbrook, R David; Scott, Keana C K; Murphy, Karen E; Petersen, Elijah J; Yu, Lee L; Nelson, Bryant C

    2017-01-24

    For environmental studies assessing uptake of orally ingested engineered nanoparticles (ENPs), a key step in ensuring accurate quantification of ingested ENPs is efficient separation of the organism from ENPs that are either nonspecifically adsorbed to the organism and/or suspended in the dispersion following exposure. Here, we measure the uptake of 30 and 60 nm gold nanoparticles (AuNPs) by the nematode, Caenorhabditis elegans, using a sucrose density gradient centrifugation protocol to remove noningested AuNPs. Both conventional inductively coupled plasma mass spectrometry (ICP-MS) and single particle (sp)ICP-MS are utilized to measure the total mass and size distribution, respectively, of ingested AuNPs. Scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDS) imaging confirmed that traditional nematode washing procedures were ineffective at removing excess suspended and/or adsorbed AuNPs after exposure. Water rinsing procedures had AuNP removal efficiencies ranging from 57 to 97% and 22 to 83%, while the sucrose density gradient procedure had removal efficiencies of 100 and 93 to 98%, respectively, for the 30 and 60 nm AuNP exposure conditions. Quantification of total Au uptake was performed following acidic digestion of nonexposed and Au-exposed nematodes, whereas an alkaline digestion procedure was optimized for the liberation of ingested AuNPs for spICP-MS characterization. Size distributions and particle number concentrations were determined for AuNPs ingested by nematodes with corresponding confirmation of nematode uptake via high-pressure freezing/freeze substitution resin preparation and large-area SEM imaging. Methods for the separation and in vivo quantification of ENPs in multicellular organisms will facilitate robust studies of ENP uptake, biotransformation, and hazard assessment in the environment.

  1. Mechanical properties of dental Ti-Ag alloys with 22.5, 25, 27.5, and 30 mass% Ag.

    PubMed

    Takahashi, Masatoshi; Kikuchi, Masafumi; Takada, Yukyo

    2015-01-01

    The mechanical properties -tensile strength, yield strength, elongation after fracture, Vickers hardness, and Young's modulus-and the phases of Ti-Ag alloys were investigated, as prepared with 22.5, 25, 27.5, and 30 mass% Ag. The tensile strength, yield strength, hardness, and Young's modulus of the alloys increase with their Ag content up to 25 mass%, but their breaking elongation decreases. These changes in the mechanical properties are attributed to solid-solution strengthening of the α-titanium phase, to Ti2Ag precipitation, and to the formation of eutectic structures composed of α+Ti2Ag. The addition of Ag, at 25 mass% in particular, improves the mechanical properties of these alloys, making them suitable for high strength dental prostheses, such as implantretained superstructures and narrow-diameter implants.

  2. Heparinized PLLA/PLCL nanofibrous scaffold for potential engineering of small-diameter blood vessel: tunable elasticity and anticoagulation property.

    PubMed

    Wang, Weizhong; Hu, Jinwei; He, Chuanglong; Nie, Wei; Feng, Wei; Qiu, Kexin; Zhou, Xiaojun; Gao, Yu; Wang, Guoqing

    2015-05-01

    The success of tissue engineered vascular grafts depends greatly on the synthetic tubular scaffold, which can mimic the architecture, mechanical, and anticoagulation properties of native blood vessels. In this study, small-diameter tubular scaffolds were fabricated with different weight ratios of poly(l-lactic acid) (PLLA) and poly(l-lactide-co-ɛ-caprolactone) (PLCL) by means of thermally induced phase separation technique. To improve the anticoagulation property of materials, heparin was covalently linked to the tubular scaffolds by N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride and N-hydroxysuccinimide coupling chemistry. The as-prepared PLLA/PLCL scaffolds retained microporous nanofibrous structure as observed in the neat PLLA scaffolds, and their structural and mechanical properties can be fine-tuned by changing the ratio of two components. The scaffold containing 60% PLCL content was found to be the most promising scaffold for engineering small-diameter blood vessel in terms of elastic properties and structural integrity. The heparinized scaffolds showed higher hydrophilicity, lower protein adsorption ability, and better in vitro anticoagulation property than their untreated counterparts. Pig iliac endothelial cells seeded on the heparinized scaffold showed good cellular attachment, spreading, proliferation, and phenotypic maintenance. Furthermore, the heparinized scaffolds exhibited neovascularization after subcutaneous implantation into the New Zealand white rabbits for 1 and 2 months. Taken together, the heparinized PLLA/PLCL nanofibrous scaffolds have the great potential for vascular tissue engineering application.

  3. Physical properties of high-mass clumps in different stages of evolution

    NASA Astrophysics Data System (ADS)

    Giannetti, A.; Brand, J.; Sánchez-Monge, Á.; Fontani, F.; Cesaroni, R.; Beltrán, M. T.; Molinari, S.; Dodson, R.; Rioja, M. J.

    2013-08-01

    Context. The details of the process of massive star formation are still elusive. A complete characterization of the first stages of the process from an observational point of view is needed to constrain theories on the subject. In the past 20 years we have made a thorough investigation of colour-selected IRAS sources over the whole sky. The sources in the northern hemisphere were studied in detail and used to derive an evolutionary sequence based on their spectral energy distribution. Aims: To investigate the first stages of the process of high-mass star formation, we selected a sample of massive clumps previously observed with the Swedish-ESO Submillimetre Telescope at 1.2 mm and with the ATNF Australia Telescope Compact Array at 1.3 cm. We want to characterize the physical conditions in such sources, and test whether their properties depend on the evolutionary stage of the clump. Methods: With ATCA we observed the selected sources in the NH3(1, 1) and (2, 2) transitions and in the H2O(616-523) maser line. Ammonia lines are a very good temperature probe that allow us to accurately determine the mass and the column, volume, and surface densities of the clumps. We also collected all data available to construct the spectral energy distribution of the individual clumps and to determine if star formation is already occurring through observations of its most common signposts, thus putting constraints on the evolutionary stage of the source. We fitted the spectral energy distribution between 1.2 mm and 70 μm with a modified black body to derive the dust temperature and independently determine the mass. Results: We find that the clumps are cold (T ~ 10-30 K), massive (M ~ 102-103 M⊙), and dense (n(H2) ≳ 105 cm-3) and that they have high column densities (N(H2) ~ 1023 cm-2). All clumps appear to be potentially able to form high-mass stars. The most massive clumps appear to be gravitationally unstable, if the only sources of support against collapse are turbulence and

  4. Appolonian Packing and Fractal Shape of Grains Improving Geomechanical Properties in Engineering Geology

    NASA Astrophysics Data System (ADS)

    Hecht, C. A.

    Fractal packing and highly irregular shaped particles increase the mechanical properties of rocks and building materials. This suggests that fractal methods are good tools for modeling particle mixes with efficient properties like maximum strength and maximum surface area or minimum porosity and minimum permeability. However gradings and packings are calculated by ``Euclidean'' disk models and sphere models. Surprisingly even the simplest models are far more complex than they appear. The fractal ``Appolonian packing model'' is proposed as the most universal two-dimensional packing model. However the inhomogeneity of gradings and the irregularity of natural grain shapes and surfaces are not reflected by these models. Consequently calculations are often far from empirical observations and experimental results. A thorough quantification of packings and gradings is important for many reasons and still a matter of intense investigation and controversial discussion. This study concentrates on fractal models for densely packed non-cohesive rocks, crushed mineral assemblages, concrete and asphalt mixtures. A summary of fractal grain size distributions with linear cumulative curves on log-log plots is presented for these mixtures. It is shown that fractal two-dimensional and three-dimensional models for dense packings reflect different physical processes of material mixing or geological deposition. The results from shear-box experiments on materials with distinct grain size distributions show a remarkable increase of the mechanical strength from non-fractal to fractal mixtures. It is suggested that fractal techniques need more systematical application and correlation with results from material testing experiments in engineering geology. The purpose of future work should lead towards the computability of dense packings of angular particles in three dimensions.

  5. [Effects of Cultivation Soil Properties on the Transport of Genetically Engineered Microorganism in Huabei Plain].

    PubMed

    Zhang, Jing; Liu, Ping; Liu, Chun; Chen, Xiao-xuan; Zhang, Lei

    2015-12-01

    The transport of genetically engineered microorganism (GEM) in the soil is considered to be the important factor influencing the enhanced bioremediation of polluted soil. The transport of an atrazine-degrading GEM and its influencing factors were investigated in the saturated cultivation soil of Huabei Plain. The results showed that horizontal infiltration was the main mechanism of GEM transport in the saturated cultivation soil. The transport process could be simulated using the filtration model. Soil properties showed significant effects on pore water flow and GEM transport in saturated soil. When particle size, porosity and sand component of the soil increased, the hydraulic conductivity constant increased and filtration coefficient of GEM decreased in saturated soil, indicating the reduced retention of GEM in the soil. An increase in infiltration flow also increased hydraulic conductivity constant in saturated soil and consequently decreased filtration coefficient of GEM. When hydraulic conductivity constants ranged from 5.02 m · d⁻¹ to 6.70 m · d⁻¹ in the saturated soil, the filtration coefficients of GEM varied from 0.105 to 0.274. There was a significantly negative correlation between them.

  6. An Analysis of the Impact of Selected Fuel Thermochemical Properties on Internal Combustion Engine Efficiency

    SciTech Connect

    Szybist, James P; Chakravathy, Kalyana; Daw, C Stuart

    2012-01-01

    In this study we model the effects of 23 different fuels on First and Second Law thermodynamic efficiency of an adiabatic internal combustion engine. First Law efficiency is calculated using lower heating value (LHV) while Second Law efficiency is calculated with exergy, which represents the inherent chemical energy available to produce propulsion. We find that First Law efficiency can deviate by as much as nine percentage points between fuels while Second Law efficiency exhibits a much smaller degree of variability. We also find that First and Second Law efficiency can be nearly the same for some fuels (methane and ethane) but differ substantially for other fuels (hydrogen and ethanol). The differences in First and Second Law efficiency are due to differences in LHV and exergy for a given fuel. In order to explain First Law efficiency differences between fuels as well as the differences between LHV and exergy, we introduce a new term: the molar expansion ratio (MER), defined as the ratio of product moles to reactant moles for complete stoichiometric combustion. We find that the MER is a useful expression for providing a physical explanation for fuel-specific efficiency differences as well as differences between First and Second Law efficiency. First and Second Law efficiency are affected by a number of other fuel-specific thermochemical properties, such as the ratio of specific heat and dissociation of combustion products.

  7. Developing a geologic and engineering properties data base with INGRES. [Yucca Mountain Project

    SciTech Connect

    Krebs-Jespersen, M.L.

    1989-01-01

    The design of a data base for storing diverse geological and site engineering properties data from various sources using the INGRES data base management system has required (1) designing tables for data that are similar but have very different test conditions to be reported, (2) determining what data is necessary to ensure that all records are unique, (3) changing, as necessary, the design of data base tables to accommodate the needs of new data submittals, (4) defining limits to comments and descriptions of test conditions to be stored in the data base, (5) solving problems caused by the limitations of the available field types in INGRES, and (6) designing a tracking system for data submissions to satisfy Project quality assurance requirements. The resulting relational data base design is simple, flexible, and capable of accommodating changes in requirements for data storage and user needs. The INGRES Report Writer utility has proven to be a powerful tool for generating reports because the Report Writer code is easily revised as table structure changes. Separate data storage tables can be joined for report production, and output can be customized for each user.

  8. Enhanced mechanical properties of thermosensitive chitosan hydrogel by silk fibers for cartilage tissue engineering.

    PubMed

    Mirahmadi, Fereshteh; Tafazzoli-Shadpour, Mohammad; Shokrgozar, Mohammad Ali; Bonakdar, Shahin

    2013-12-01

    Articular cartilage has limited repair capability following traumatic injuries and current methods of treatment remain inefficient. Reconstructing cartilage provides a new way for cartilage repair and natural polymers are often used as scaffold because of their biocompatibility and biofunctionality. In this study, we added degummed chopped silk fibers and electrospun silk fibers to the thermosensitive chitosan/glycerophosphate hydrogels to reinforce two hydrogel constructs which were used as scaffold for hyaline cartilage regeneration. The gelation temperature and gelation time of hydrogel were analyzed by the rheometer and vial tilting method. Mechanical characterization was measured by uniaxial compression, indentation and dynamic mechanical analysis assay. Chondrocytes were then harvested from the knee joint of the New Zealand white rabbits and cultured in constructs. The cell proliferation, viability, production of glycosaminoglycans and collagen type II were assessed. The results showed that mechanical properties of the hydrogel were significantly enhanced when a hybrid with two layers of electrospun silk fibers was made. The results of GAG and collagen type II in cell-seeded scaffolds indicate support of the chondrogenic phenotype for chondrocytes with a significant increase in degummed silk fiber-hydrogel composite for GAG content and in two-layer electrospun fiber-hydrogel composite for Col II. It was concluded that these two modified scaffolds could be employed for cartilage tissue engineering.

  9. Mechanical properties of electrospun bilayer fibrous membranes as potential scaffolds for tissue engineering.

    PubMed

    Pu, Juan; Komvopoulos, Kyriakos

    2014-06-01

    Bilayer fibrous membranes of poly(l-lactic acid) (PLLA) were fabricated by electrospinning, using a parallel-disk mandrel configuration that resulted in the sequential deposition of a layer with fibers aligned across the two parallel disks and a layer with randomly oriented fibers, both layers deposited in a single process step. Membrane structure and fiber alignment were characterized by scanning electron microscopy and two-dimensional fast Fourier transform. Because of the intricacies of the generated electric field, bilayer membranes exhibited higher porosity than single-layer membranes consisting of randomly oriented fibers fabricated with a solid-drum collector. However, despite their higher porosity, bilayer membranes demonstrated generally higher elastic modulus, yield strength and toughness than single-layer membranes with random fibers. Bilayer membrane deformation at relatively high strain rates comprised multiple abrupt microfracture events characterized by discontinuous fiber breakage. Bilayer membrane elongation yielded excessive necking of the layer with random fibers and remarkable fiber stretching (on the order of 400%) in the layer with fibers aligned in the stress direction. In addition, fibers in both layers exhibited multiple localized necking, attributed to the nonuniform distribution of crystalline phases in the fibrillar structure. The high membrane porosity, good mechanical properties, and good biocompatibility and biodegradability of PLLA (demonstrated in previous studies) make the present bilayer membranes good scaffold candidates for a wide range of tissue engineering applications.

  10. Strong Modulation of Optical Properties in Black Phosphorus through Strain-Engineered Rippling.

    PubMed

    Quereda, Jorge; San-Jose, Pablo; Parente, Vincenzo; Vaquero-Garzon, Luis; Molina-Mendoza, Aday J; Agraït, Nicolás; Rubio-Bollinger, Gabino; Guinea, Francisco; Roldán, Rafael; Castellanos-Gomez, Andres

    2016-05-11

    Controlling the bandgap through local-strain engineering is an exciting avenue for tailoring optoelectronic materials. Two-dimensional crystals are particularly suited for this purpose because they can withstand unprecedented nonhomogeneous deformations before rupture; one can literally bend them and fold them up almost like a piece of paper. Here, we study multilayer black phosphorus sheets subjected to periodic stress to modulate their optoelectronic properties. We find a remarkable shift of the optical absorption band-edge of up to ∼0.7 eV between the regions under tensile and compressive stress, greatly exceeding the strain tunability reported for transition metal dichalcogenides. This observation is supported by theoretical models that also predict that this periodic stress modulation can yield to quantum confinement of carriers at low temperatures. The possibility of generating large strain-induced variations in the local density of charge carriers opens the door for a variety of applications including photovoltaics, quantum optics, and two-dimensional optoelectronic devices.

  11. Nano-composite scaffolds for bone tissue engineering containing silver nanoparticles: preparation, characterization and biological properties.

    PubMed

    Marsich, Eleonora; Bellomo, Francesca; Turco, Gianluca; Travan, Andrea; Donati, Ivan; Paoletti, Sergio

    2013-07-01

    In this study nano-composite scaffolds to be used as bone grafts have been endowed with antibacterial properties owing to the presence of silver nanoparticles. The alginate/hydroxyapatite composite scaffolds were prepared by internal gelation followed by a freeze-drying procedure to obtain a porous structure. The nanoparticles were prepared in presence of a lactose modified-chitosan and this colloidal solution was adsorbed on the scaffolds by exploiting electrostatic interactions. The adsorption and release of the silver from the composite scaffold was measured by ICP-AES and spectrofluorimetry measurements. Micro-computed tomography analysis of the scaffolds showed a homogeneous porous structure with average pore sizes of 341.5 μm and porosity of 80 %. In vitro biological tests (MTS and killing kinetics assays) demonstrated that silver does not affect the ability of the scaffolds to promote osteoblasts proliferation and that at the same time it exerts a strong bactericidal effect against both Gram+ and Gram- bacterial strains. Overall, the combined results indicate that these biocompatible antimicrobial scaffolds possess ideal characteristics for tissue engineering applications.

  12. Secondary materials: Engineering properties, environmental consequences, and social and economic impacts. Final report

    SciTech Connect

    Breslin, V.; Reaven, S.; Schwartz, M.; Swanson, L.; Zweig, M.; Bortman, M.; Schubel, J.

    1993-08-01

    This report investigates two secondary materials, plastic lumber made from mixed plastic waste, and cement blocks and structures made with incinerator ash. Engineering properties, environmental impacts, and energy costs and savings of these secondary materials are compared to standard lumber products and cement blocks. Market capacity and social acceptance of plastic lumber and stabilized ash products are analyzed. These secondary materials apparently have potential markets; however, their economic value is primarily that they will not take up landfill space. For plastic lumber and stabilized incinerator ash products, marine and highway construction seem ideal public works applications. Incinerator ash may be suitable to use in seawalls, jetties, fishing reefs, highway barriers, and roadbed applications. Docks, piers, highway sound barriers, parking stops, and park furniture may all be made from plastic lumber. To encourage public acceptance and improve the market potential of secondary materials, these activities could be beneficial: industry should emphasize developing useful, long-lived products; industry and governments should create product performance criteria; government should provide rigorous testing and demonstration programs; and government and industry should cooperate to improve public outreach and educational programs.

  13. Silver and Gold Nanostructures: Engineering their Optical Properties for Biomedical Applications.

    NASA Astrophysics Data System (ADS)

    Xia, Younan

    2006-03-01

    We have focused on shape-controlled synthesis of silver and gold nanostructures. While the synthetic methodology mainly involves solution-phase redox chemistry, we have been working diligently to understand the complex physics behind the simple chemistry -- that is, the nucleation and growth mechanisms leading to the formation of nanostructures with a specific shape. Polyol synthesis of silver nanostructures provides a good example to illustrate this concept. We discovered that the shape of silver nanostructures were dictated by both the crystallinity and shape of nanocrystallite seeds, which were, in turn, controlled by factors such as reduction rate, oxidative etching, and surface capping. We also exploited the galvanic replacement reaction between silver and chloroauric acid to transform silver nanocubes into gold nanocages with controlled void size, wall thickness, and wall porosity. We were able to engineer the optical properties of resulting gold nanocages with optical resonance peaks ranging from the blue (400 nm) to the near infrared (1200 nm) simply by controlling the molar ratio of silver to chloroauric acid. Thanks to their exceptionally large scattering and absorption coefficients in the transparent window for soft tissues, this novel class of gold nanostructures has great potential emerging as both a contrast agent for optical imaging in early-stage tumor detection, and a therapeutic agent for photothermal cancer treatment.

  14. Strain-engineered optoelectronic properties of 2D transition metal dichalcogenide lateral heterostructures

    DOE PAGES

    Lee, Jaekwang; Huang, Jingsong; Sumpter, Bobby G.; ...

    2017-02-17

    Compared with their bulk counterparts, 2D materials can sustain much higher elastic strain at which optical quantities such as bandgaps and absorption spectra governing optoelectronic device performance can be modified with relative ease. Using first-principles density functional theory and quasiparticle GW calculations, we demonstrate how uniaxial tensile strain can be utilized to optimize the electronic and optical properties of transition metal dichalcogenide lateral (in-plane) heterostructures such as MoX2/WX2 (X = S, Se, Te). We find that these lateral-type heterostructures may facilitate efficient electron–hole separation for light detection/harvesting and preserve their type II characteristic up to 12% of uniaxial strain. Basedmore » on the strain-dependent bandgap and band offset, we show that uniaxial tensile strain can significantly increase the power conversion efficiency of these lateral heterostructures. Our results suggest that these strain-engineered lateral heterostructures are promising for optimizing optoelectronic device performance by selectively tuning the energetics of the bandgap.« less

  15. Plant diversity does not buffer drought effects on early-stage litter mass loss rates and microbial properties.

    PubMed

    Vogel, Anja; Eisenhauer, Nico; Weigelt, Alexandra; Scherer-Lorenzen, Michael

    2013-09-01

    Human activities are decreasing biodiversity and changing the climate worldwide. Both global change drivers have been shown to affect ecosystem functioning, but they may also act in concert in a non-additive way. We studied early-stage litter mass loss rates and soil microbial properties (basal respiration and microbial biomass) during the summer season in response to plant species richness and summer drought in a large grassland biodiversity experiment, the Jena Experiment, Germany. In line with our expectations, decreasing plant diversity and summer drought decreased litter mass loss rates and soil microbial properties. In contrast to our hypotheses, however, this was only true for mass loss of standard litter (wheat straw) used in all plots, and not for plant community-specific litter mass loss. We found no interactive effects between global change drivers, that is, drought reduced litter mass loss rates and soil microbial properties irrespective of plant diversity. High mass loss rates of plant community-specific litter and low responsiveness to drought relative to the standard litter indicate that soil microbial communities were adapted to decomposing community-specific plant litter material including lower susceptibility to dry conditions during summer months. Moreover, higher microbial enzymatic diversity at high plant diversity may have caused elevated mass loss of standard litter. Our results indicate that plant diversity loss and summer drought independently impede soil processes. However, soil decomposer communities may be highly adapted to decomposing plant community-specific litter material, even in situations of environmental stress. Results of standard litter mass loss moreover suggest that decomposer communities under diverse plant communities are able to cope with a greater variety of plant inputs possibly making them less responsive to biotic changes.

  16. Engineering processes in meat products and how they influence their biophysical properties.

    PubMed

    Tornberg, E

    2013-12-01

    Food engineering aspects of cooking of meat products in relation to their biophysical properties, such as water- and fat-holding, have been reviewed. Moreover, some of the new emerging, mild cooking technologies, such as high pressure and electro-based heating (radio frequency cooking and ohmic heating) have been discussed in relation to the biophysical properties of the meat products treated. The holding of the bulk water (about 70% of the muscle weight) was discussed, arguing capillary forces to be one of the dominating mechanisms for this holding, whereas the losses of water and fat (the flow) within the meat are governed by Darcy's law. If we compare the fat-holding in beef burgers and emulsion sausages (frankfurter type) beef burgers lose much larger part of the fat than the emulsion sausages and for the former the fat losses increase with fat content. For emulsion sausages, however, fat losses are independent of fat content and the properties of the fat and the protein matrix are more interrelated. It has been shown experimentally during double sided pan frying of beef burgers that the pressure driven water loss (up to 80% of the water loss) is a substantially more important mechanism governing the water loss than the evaporation losses occurring at the surface crust. Fat losses increased significantly with fat content and were not influenced to any large extent by the cooking temperature and were in the form of drip. By using processing technologies such as high pressure and/or electro-based heating (radio frequency cooking and ohmic heating) a more homogenous heating can be achieved, the reason being volumetric heating. In comparison with conventional heating shorter cooking times were obtained and with smaller temperature gradients lower water- and fat-losses occurred and the yield can be substantially improved. High pressure processing (100-1000MPa) is a preservation technology that allows the reduction of the microbial load at low or moderate temperature

  17. A non-contacting vertical alignment system for mass properties measuring instruments

    SciTech Connect

    James, G.H. III; Suazo, J.E.; Varga, R.C.

    1993-11-01

    A non-contact system for alignment of objects on mass properties measuring instruments is described. Test parts can be aligned to within the capabilities of the user and the fixture to make the adjustments. The current implementation can align objects to less than .001 inches at two points with final requested adjustments of a few ten-thousands of an inch. The non-contact capability allows the alignment of objects which are too compliant or fragile for traditional contacting measurement methods. Also, this system allows the definition of a reference axis on objects which are not perfectly symmetric. The reference axis is defined at the top of the object by an appropriate marker and defined at the bottom by a best fit circle through the surface at a specified height. A general description of the hardware, procedures, and results are presented for the non-user. Appendices which contain a complete description of the software, usage, and mathematical implementation are provided for the reader who is interested in using or further developing the system.

  18. Three-Dimensional Properties of Coronal Mass Ejections from STEREO/SECCHI Observations

    NASA Astrophysics Data System (ADS)

    Bosman, E.; Bothmer, V.; Nisticò, G.; Vourlidas, A.; Howard, R. A.; Davies, J. A.

    2012-11-01

    We identify 565 coronal mass ejections (CMEs) between January 2007 and December 2010 in observations from the twin STEREO/SECCHI/COR2 coronagraphs aboard the STEREO mission. Our list is in full agreement with the corresponding SOHO/LASCO CME Catalog (http://cdaw.gsfc.nasa.gov/CME_list/) for events with angular widths of 45∘ and up. The monthly event rates behave similarly to sunspot rates showing a three- to fourfold rise between September 2009 and March 2010. We select 51 events with well-defined white-light structure and model them as three-dimensional (3D) flux ropes using a forward-modeling technique developed by Thernisien, Howard and Vourlidas (Astrophys. J. 652, 763 - 773, 2006). We derive their 3D properties and identify their source regions. We find that the majority of the CME flux ropes (82 %) lie within 30∘ of the solar equator. Also, 82 % of the events are displaced from their source region, to a lower latitude, by 25∘ or less. These findings provide strong support for the deflection of CMEs towards the solar equator reported in earlier observations, e.g. by Cremades and Bothmer ( Astron. Astrophys. 422, 307 - 322, 2004).

  19. Models for determining the geometrical properties of halo coronal mass ejections

    NASA Astrophysics Data System (ADS)

    Zhao, X.; Liu, Y.

    2005-12-01

    To this day, the prediction of space weather effects near the Earth suffer from a fundamental problem: the necessary condition for determining whether or not and when a part of the huge interplanetary counterpart (ICME) of frontside halo coronal mass ejections (CMEs) is able to hit the Earth and generate goemagnetic storms, i.e., the real angular width, the propagation direction and speed of the CMEs, cannot be measured directly because of the unfavorable geometry. To inverse these geometrical and kinematical properties we have recently developed a few geometrical models, such as the cone model, the ice cream cone model, and the spherical cone model. The inversing solution of the cone model for the 12 may 1997 halo CME has been used as an input to the ENLIL model (a 3D MHD solar wind code) and successfully predicted the ICME near the Earth (Zhao, Plukett & Liu, 2002; Odstrcil, Riley & Zhao, 2004). After briefly describing the geometrical models this presentation will discuss: 1. What kind of halo CMEs can be inversed? 2. How to select the geometrical models given a specific halo CME? 3. Whether or not the inversing solution is unique?

  20. The Low-mass Population in the Young Cluster Stock 8: Stellar Properties and Initial Mass Function

    NASA Astrophysics Data System (ADS)

    Jose, Jessy; Herczeg, Gregory J.; Samal, Manash R.; Fang, Qiliang; Panwar, Neelam

    2017-02-01

    The evolution of H ii regions/supershells can trigger a new generation of stars/clusters at their peripheries, with environmental conditions that may affect the initial mass function, disk evolution, and star formation efficiency. In this paper we study the stellar content and star formation processes in the young cluster Stock 8, which itself is thought to be formed during the expansion of a supershell. We present deep optical photometry along with JHK and 3.6 and 4.5 μm photometry from UKIDSS and Spitzer-IRAC. We use multicolor criteria to identify the candidate young stellar objects in the region. Using evolutionary models, we obtain a median log(age) of ∼6.5 (∼3.0 Myr) with an observed age spread of ∼0.25 dex for the cluster. Monte Carlo simulations of the population of Stock 8, based on estimates for the photometric uncertainty, differential reddening, binarity, and variability, indicate that these uncertainties introduce an age spread of ∼0.15 dex. The intrinsic age spread in the cluster is ∼0.2 dex. The fraction of young stellar objects surrounded by disks is ∼35%. The K-band luminosity function of Stock 8 is similar to that of the Trapezium cluster. The initial mass function (IMF) of Stock 8 has a Salpeter-like slope at >0.5 M ⊙ and flattens and peaks at ∼0.4 M ⊙, below which it declines into the substellar regime. Although Stock 8 is surrounded by several massive stars, there seems to be no severe environmental effect in the form of the IMF due to the proximity of massive stars around the cluster.

  1. Peanut protein reduces body protein mass and alters skeletal muscle contractile properties and lipid metabolism in rats.

    PubMed

    Jacques, Hélène; Leblanc, Nadine; Papineau, Roxanne; Richard, Denis; Côté, Claude H

    2010-05-01

    It is well known that diets high in nuts or peanuts favourably affect plasma lipid concentrations. However, few studies have examined the effects of nut and peanut protein (PP) on body composition and skeletal muscle properties. The present study was aimed at evaluating the effect of dietary PP compared with two animal proteins, casein (C) and cod protein (CP) on body composition, skeletal muscle contractile properties and lipid metabolism in rats. Thirty-two male rats were assigned to one of the following four diets containing either C, CP, PP or C+peanut protein (CPP, 50:50) mixture. After 28 d of ad libitum feeding and after 12-h fast, blood, liver and muscle were collected for measurements of plasma and hepatic cholesterol and TAG, plasma glucose and insulin and contractile properties. Rats fed with the low-quality protein, PP, had lower body weight gain, body protein mass, soleus mass and liver weight than those fed with the high-quality dietary proteins, C and CP. PP also caused a deficit in contractile properties in soleus. Likewise, PP increased plasma cholesterol and body fat mass compared with CP. However, these elevations were accompanied with increased hepatic TAG concentrations and lowered intestinal fat excretion. These results show that PP intake alters body composition by reducing skeletal muscle mass and liver weight as well as muscle contractility and lipid metabolism. Adding a complete protein such as C might partially counteract these adverse effects.

  2. On-Line, Gyro-Based, Mass-Property Identification for Thruster-Controlled Spacecraft Using Recursive Least Squares

    NASA Technical Reports Server (NTRS)

    Wilson, Edward; Lages, Chris; Mah, Robert; Clancy, Daniel (Technical Monitor)

    2002-01-01

    Spacecraft control, state estimation, and fault-detection-and-isolation systems are affected by unknown v aerations in the vehicle mass properties. It is often difficult to accurately measure inertia terms on the ground, and mass properties can change on-orbit as fuel is expended, the configuration changes, or payloads are added or removed. Recursive least squares -based algorithms that use gyro signals to identify the center of mass and inverse inertia matrix are presented. They are applied in simulation to 3 thruster-controlled vehicles: the X-38 and Mini-AERCam under development at NASA-JSC, and the SAM, an air-bearing spacecraft simulator at the NASA-Ames Smart Systems Research Lab (SSRL).

  3. Summer Work Experience: Determining Methane Combustion Mechanisms and Sub-Scale Diffuser Properties for Space Transporation System Engine Testing

    NASA Technical Reports Server (NTRS)

    Williams, Powtawche N.

    1998-01-01

    To assess engine performance during the testing of Space Shuttle Main Engines (SSMEs), the design of an optimal altitude diffuser is studied for future Space Transportation Systems (STS). For other Space Transportation Systems, rocket propellant using kerosene is also studied. Methane and dodecane have similar reaction schemes as kerosene, and are used to simulate kerosene combustion processes at various temperatures. The equations for the methane combustion mechanism at high temperature are given, and engine combustion is simulated on the General Aerodynamic Simulation Program (GASP). The successful design of an altitude diffuser depends on the study of a sub-scaled diffuser model tested through two-dimensional (2-D) flow-techniques. Subroutines given calculate the static temperature and pressure at each Mach number within the diffuser flow. Implementing these subroutines into program code for the properties of 2-D compressible fluid flow determines all fluid characteristics, and will be used in the development of an optimal diffuser design.

  4. Engineering Protein Allostery: 1.05 Å Resolution Structure and Enzymatic Properties of a Na[superscript +]-activated Trypsin

    SciTech Connect

    Page, Michael J.; Carrell, Christopher J.; Di Cera, Enrico

    2008-05-28

    Some trypsin-like proteases are endowed with Na{sup +}-dependent allosteric enhancement of catalytic activity, but this important mechanism has been difficult to engineer in other members of the family. Replacement of 19 amino acids in Streptomyces griseus trypsin targeting the active site and the Na{sup +}-binding site were found necessary to generate efficient Na{sup +} activation. Remarkably, this property was linked to the acquisition of a new substrate selectivity profile similar to that of factor Xa, a Na{sup -} activated protease involved in blood coagulation. The X-ray crystal structure of the mutant trypsin solved to 1.05 {angstrom} resolution defines the engineered Na{sup +} site and active site loops in unprecedented detail. The results demonstrate that trypsin can be engineered into an efficient allosteric protease, and that Na+ activation is interwoven with substrate selectivity in the trypsin scaffold.

  5. Identification and quantification analysis of nonlinear dynamics properties of combustion instability in a diesel engine.

    PubMed

    Yang, Li-Ping; Ding, Shun-Liang; Litak, Grzegorz; Song, En-Zhe; Ma, Xiu-Zhen

    2015-01-01

    The cycling combustion instabilities in a diesel engine have been analyzed based on chaos theory. The objective was to investigate the dynamical characteristics of combustion in diesel engine. In this study, experiments were performed under the entire operating range of a diesel engine (the engine speed was changed from 600 to 1400 rpm and the engine load rate was from 0% to 100%), and acquired real-time series of in-cylinder combustion pressure using a piezoelectric transducer installed on the cylinder head. Several methods were applied to identify and quantitatively analyze the combustion process complexity in the diesel engine including delay-coordinate embedding, recurrence plot (RP), Recurrence Quantification Analysis, correlation dimension (CD), and the largest Lyapunov exponent (LLE) estimation. The results show that the combustion process exhibits some determinism. If LLE is positive, then the combustion system has a fractal dimension and CD is no more than 1.6 and within the diesel engine operating range. We have concluded that the combustion system of diesel engine is a low-dimensional chaotic system and the maximum values of CD and LLE occur at the lowest engine speed and load. This means that combustion system is more complex and sensitive to initial conditions and that poor combustion quality leads to the decrease of fuel economy and the increase of exhaust emissions.

  6. Identification and quantification analysis of nonlinear dynamics properties of combustion instability in a diesel engine

    SciTech Connect

    Yang, Li-Ping Ding, Shun-Liang; Song, En-Zhe; Ma, Xiu-Zhen; Litak, Grzegorz

    2015-01-15

    The cycling combustion instabilities in a diesel engine have been analyzed based on chaos theory. The objective was to investigate the dynamical characteristics of combustion in diesel engine. In this study, experiments were performed under the entire operating range of a diesel engine (the engine speed was changed from 600 to 1400 rpm and the engine load rate was from 0% to 100%), and acquired real-time series of in-cylinder combustion pressure using a piezoelectric transducer installed on the cylinder head. Several methods were applied to identify and quantitatively analyze the combustion process complexity in the diesel engine including delay-coordinate embedding, recurrence plot (RP), Recurrence Quantification Analysis, correlation dimension (CD), and the largest Lyapunov exponent (LLE) estimation. The results show that the combustion process exhibits some determinism. If LLE is positive, then the combustion system has a fractal dimension and CD is no more than 1.6 and within the diesel engine operating range. We have concluded that the combustion system of diesel engine is a low-dimensional chaotic system and the maximum values of CD and LLE occur at the lowest engine speed and load. This means that combustion system is more complex and sensitive to initial conditions and that poor combustion quality leads to the decrease of fuel economy and the increase of exhaust emissions.

  7. Monitoring water masses properties by Glider in Sardinia Channel during summer 2014

    NASA Astrophysics Data System (ADS)

    Gana, Slim; Iudicone, Daniele; Ghenim, Leila; Mortier, Laurent; Testor, Pierre; Tintoré, Joaquin; Olita, Antonio

    2015-04-01

    1. Summary In the framework of the EC funded project, PERSEUS (WP3, Subtask 3.3.1: Repeated glider sections in key channels and sub-basin) and with the support of JERICO TNA (EU-FP7), a deep water glider (up to 1000m) was deployed from the R/V Tethys in the Sardinia Channel and has carried out 3 return trips during the period spanning from the 16th of August 2014 to the 19th of September 2014. The Gilder was equipped with CTD, O2 sensors, Fluorometers (ChlA), back scattering from 470 to 880 nm and was programmed to follow a path close to SARAL satellite track #887. During this experiment, a significant dataset, as never obtained before for this area, has been collected. The innovation stands in the high spatial resolution, in the temporal repetitivity and in the number of parameters sampled simultaneously. The first step of the work will focuses on the analysis of the hydrological properties of the existing water masses in the area. 2. Frame and aim of the experiment The Sardinia Channel is a zonally oriented passage connecting the Algerian and the Tyrrhenian basins, with a sill depth of about 1900 m. In spite of the considerable amount of work achieved and accurate results obtained about the circulation in the Western Mediterranean Sea, during the last 20 years, the Sardinia Channel is still one of the region where the dynamical processes and water exchanges are not clearly identified. Previous studies (Garzoli S. and C. Maillard, 1979, and Ozturgut Erdogan, 1975) pointed out the complexity of the processes in the region and the role of the bottom topography in sustaining them, and provided a first estimation of the involved fluxes. The main knowledge about the water masses crossing this region mostly concerns the AW (Atlantic Water) and the LIW (Levantine Intermediate Water). Along the Algerian coast, the AW is transported mainly by the Algerian current (AC Millot, 1985) from which the anticyclonic Algerian eddies (AEs, Puillat et al., 2002; Taupier-Letage et al

  8. Development of property-transfer models for estimating the hydraulic properties of deep sediments at the Idaho National Engineering and Environmental Laboratory, Idaho

    USGS Publications Warehouse

    Winfield, Kari A.

    2005-01-01

    Because characterizing the unsaturated hydraulic properties of sediments over large areas or depths is costly and time consuming, development of models that predict these properties from more easily measured bulk-physical properties is desirable. At the Idaho National Engineering and Environmental Laboratory, the unsaturated zone is composed of thick basalt flow sequences interbedded with thinner sedimentary layers. Determining the unsaturated hydraulic properties of sedimentary layers is one step in understanding water flow and solute transport processes through this complex unsaturated system. Multiple linear regression was used to construct simple property-transfer models for estimating the water-retention curve and saturated hydraulic conductivity of deep sediments at the Idaho National Engineering and Environmental Laboratory. The regression models were developed from 109 core sample subsets with laboratory measurements of hydraulic and bulk-physical properties. The core samples were collected at depths of 9 to 175 meters at two facilities within the southwestern portion of the Idaho National Engineering and Environmental Laboratory-the Radioactive Waste Management Complex, and the Vadose Zone Research Park southwest of the Idaho Nuclear Technology and Engineering Center. Four regression models were developed using bulk-physical property measurements (bulk density, particle density, and particle size) as the potential explanatory variables. Three representations of the particle-size distribution were compared: (1) textural-class percentages (gravel, sand, silt, and clay), (2) geometric statistics (mean and standard deviation), and (3) graphical statistics (median and uniformity coefficient). The four response variables, estimated from linear combinations of the bulk-physical properties, included saturated hydraulic conductivity and three parameters that define the water-retention curve. For each core sample,values of each water-retention parameter were

  9. Evaluation of negative fixed-charge density in tissue-engineered cartilage by quantitative MRI and relationship with biomechanical properties.

    PubMed

    Miyata, Shogo; Homma, Kazuhiro; Numano, Tomokazu; Tateishi, Tetsuya; Ushida, Takashi

    2010-07-01

    Applying tissue-engineered cartilage in a clinical setting requires noninvasive evaluation to detect the maturity of the cartilage. Magnetic resonance imaging (MRI) of articular cartilage has been widely accepted and applied clinically in recent years. In this study, we evaluated the negative fixed-charge density (nFCD) of tissue-engineered cartilage using gadolinium-enhanced MRI and determined the relationship between nFCD and biomechanical properties. To reconstruct cartilage tissue, articular chondrocytes from bovine humeral heads were embedded in agarose gel and cultured in vitro for up to 4 weeks. The nFCD of the cartilage was determined using the MRI gadolinium exclusion method. The equilibrium modulus was determined using a compressive stress relaxation test, and the dynamic modulus was determined by a dynamic compression test. The equilibrium compressive modulus and dynamic modulus of the tissue-engineered cartilage increased with an increase in culture time. The nFCD value--as determined with the [Gd-DTPA(2-)] measurement using the MRI technique--increased with culture time. In the regression analysis, nFCD showed significant correlations with equilibrium compressive modulus and dynamic modulus. From these results, gadolinium-enhanced MRI measurements can serve as a useful predictor of the biomechanical properties of tissue-engineered cartilage.

  10. Toxicological properties of emission particles from heavy duty engines powered by conventional and bio-based diesel fuels and compressed natural gas

    PubMed Central

    2012-01-01

    Background One of the major areas for increasing the use of renewable energy is in traffic fuels e.g. bio-based fuels in diesel engines especially in commuter traffic. Exhaust emissions from fossil diesel fuelled engines are known to cause adverse effects on human health, but there is very limited information available on how the new renewable fuels may change the harmfulness of the emissions, especially particles (PM). We evaluated the PM emissions from a heavy-duty EURO IV diesel engine powered by three different fuels; the toxicological properties of the emitted PM were investigated. Conventional diesel fuel (EN590) and two biodiesels were used − rapeseed methyl ester (RME, EN14214) and hydrotreated vegetable oil (HVO) either as such or as 30% blends with EN590. EN590 and 100% HVO were also operated with or without an oxidative catalyst (DOC + POC). A bus powered by compressed natural gas (CNG) was included for comparison with the liquid fuels. However, the results from CNG powered bus cannot be directly compared to the other situations in this study. Results High volume PM samples were collected on PTFE filters from a constant volume dilution tunnel. The PM mass emission with HVO was smaller and with RME larger than that with EN590, but both biofuels produced lower PAH contents in emission PM. The DOC + POC catalyst greatly reduced the PM emission and PAH content in PM with both HVO and EN590. Dose-dependent TNFα and MIP-2 responses to all PM samples were mostly at the low or moderate level after 24-hour exposure in a mouse macrophage cell line RAW 264.7. Emission PM from situations with the smallest mass emissions (HVO + cat and CNG) displayed the strongest potency in MIP-2 production. The catalyst slightly decreased the PM-induced TNFα responses and somewhat increased the MIP-2 responses with HVO fuel. Emission PM with EN590 and with 30% HVO blended in EN590 induced the strongest genotoxic responses, which were significantly greater than

  11. Steeply dipping heaving bedrock, Colorado: Part 2 - Mineralogical and engineering properties

    USGS Publications Warehouse

    Noe, D.C.; Higgins, J.D.; Olsen, H.W.

    2007-01-01

    This paper describes the mineralogical and engineering properties of steeply dipping, differentially heaving bedrock, which has caused severe damage near the Denver area. Several field sites in heave-prone areas have been characterized using high sample densities, numerous testing methodologies, and thousands of sample tests. Hydrometer testing shows that the strata range from siltstone to claystone (33 to 66 percent clay) with occasional bentonite seams (53 to 98 percent clay mixed with calcite). From X-ray diffraction analyses, the claystone contains varying proportions of illite-smectite and discrete (pure) smectite, and the bentonite contains discrete smectite. Accessory minerals include pyrite, gypsum, calcite, and oxidized iron compounds. The dominant exchangeable cation is Ca2+, except where gypsum is prevalent, and Mg2+ and Na1+ are elevated. Scanning electron microscope analyses show that the clay fabric is deformed and porous and that pyrite is absent within the weathered zone. Unified Soil Classification for the claystone varies from CL to CH, and the bentonite is CH to MH. Average moisture content values are 17 percent for claystone and 32 percent for bentonite, and these are typically 0 to 5 percent lower than the plastic limit. Swell-consolidation and suction testing shows a full range of swelling potentials from low to very high. These findings confirm that type I (bed-parallel, symmetrical to asymmetrical) heave features are strongly associated with changes in bedrock composition and mineralogy. Composition changes are not necessarily a factor for type II (bed-parallel to bed-oblique, strongly asymmetrical) heave features, which are associated with movements along subsurface shear zones.

  12. Structure and properties of electrospun polymer fibers and applications in biomedical engineering

    NASA Astrophysics Data System (ADS)

    Casper, Cheryl L.

    2006-04-01

    Increased interest in nanotechnology has revived a fiber processing technique invented back in the 1930's. Electrospinning produces nanometer to micron size fibers that are not otherwise achievable using conventional fiber spinning methods. Due to small fiber diameters, high surface area, tailorable surface morphology, and the creation of an interconnected fibrous network, electrospun fibers have found use in a variety of applications. However, a multitude of parameters directly affect the electrospinning process thus requiring a fundamental understanding of how various parameters affect the process and resulting fiber properties. Accordingly, the focus of this dissertation is to provide insight on how solution characteristics and processing parameters directly affect the electrospinning process, and then apply this knowledge to create electrospun membranes for biomedical applications. These fundamental studies provided insight on how to control the electrospinning process; this knowledge was then utilized to electrospin fibrous membranes for biomedical applications. One aspect of this work focused on incorporating low molecular weight heparin (LMWH) into electrospun fibers. Heparin is known for its ability to bind growth factors and thus it plays an integral role in drug delivery and tissue engineering applications. The goal of this work was to fabricate functionalized electrospun fibers to produce a biologically active matrix that would allow for the binding and delivery of growth factors for possible drug delivery applications. The electrospinning process was also utilized to fabricate native polymers such as collagen and gelatin into fiber form. The collagen and gelatin fibers were 2--6 mum in diameter and required crosslinking to stabilize the fibers. Crosslinking and sterilization protocols were investigated to optimize the conditions needed to produce collagen and gelatin electrospun membranes to be used in bone regeneration applications. (Abstract shortened

  13. Physical properties and evolutionary time scales of disks around solar-type and intermediate mass stars

    NASA Technical Reports Server (NTRS)

    Strom, Stephen E.; Edwards, Suzan

    1993-01-01

    Recent observations of circumstellar disks and their evolutionary timescales are reviewed. It is concluded that disks appear to be a natural outcome of the star-formation process. The disks surrounding young stars initially are massive, with optically thick structures comprised of gas and micron-sized grains. Disk masses are found to range from 0.01 to 0.2 solar masses for solar-type PMS stars, and from 0.01 to 6 solar masses for young, intermediate mass stars. Massive, optically thick accretion disks have accretion rates between 10 exp -8 and 10 exp -6 solar masses/yr for solar type PMS stars and between 10 exp -6 and 10 exp -4 solar masses/yr for intermediate stars. The results suggest that a significant fraction of the mass comprising the star may have passed through a circumstellar accretion disk.

  14. Procedure for implementation of temperature-dependent mechanical property capability in the Engineering Analysis Language (EAL) system

    NASA Technical Reports Server (NTRS)

    Glass, David E.; Robinson, James C.

    1990-01-01

    A procedure is presented to allow the use of temperature dependent mechanical properties in the Engineering Analysis Language (EAL) System for solid structural elements. This is accomplished by including a modular runstream in the main EAL runstream. The procedure is applicable for models with multiple materials and with anisotropic properties, and can easily be incorporated into an existing EAL runstream. The procedure (which is applicable for EAL elastic solid elements) is described in detail, followed by a description of the validation of the routine. A listing of the EAL runstream used to validate the procedure is included in the Appendix.

  15. Dynamical and Physical Properties of a Post-Coronal Mass Ejection Current Sheet

    NASA Technical Reports Server (NTRS)

    Ko, Yuan-Kuen; Raymond, John C.; Lin, Jun; Lawrence, Gareth; Li, Jing; Fludra, Andrzej

    2003-01-01

    In the eruptive process of the Kopp-Pneuman type, the closed magnetic field is stretched by the eruption so much that it is usually believed to be " open " to infinity. Formation of the current sheet in such a configuration makes it possible for the energy in the coronal magnetic field to quickly convert into thermal and kinetic energies and cause significant observational consequences, such as growing postflare/CME loop system in the corona, separating bright flare ribbons in the chromosphere, and fast ejections of the plasma and the magnetic flux. An eruption on 2002 January 8 provides us a good opportunity to look into these observational signatures of and place constraints on the theories of eruptions. The event started with the expansion of a magnetic arcade over an active region, developed into a coronal mass ejection (CME), and left some thin streamer-like structures with successively growing loop systems beneath them. The plasma outflow and the highly ionized states of the plasma inside these streamer-like structures, as well as the growing loops beneath them, lead us to conclude that these structures are associated with a magnetic reconnection site, namely, the current sheet, of this eruptive process. We combine the data from the Ultraviolet Coronagraph Spectrometer, Large Angle and Spectrometric Coronagraph Experiment, EUV Imaging Telescope, and Coronal Diagnostic Spectrometer on board the Solar and Heliospheric Observatory, as well is from the Mauna Loa Solar Observatory Mark IV K-coronameter, to investigate the morphological and dynamical properties of this event, as well as the physical properties of the current sheet. The velocity and acceleration of the CME reached up to 1800 km/s and 1 km/sq s, respectively. The acceleration is found to occur mainly at the lower corona (<2.76 Solar Radius). The post-CME loop systems showed behaviors of both postflare loops (upward motion with decreasing speed) and soft X-ray giant arches (upward motion with constant

  16. Overview of aerosol properties associated with air masses sampled by the ATR-42 during the EUCAARI campaign (2008)

    NASA Astrophysics Data System (ADS)

    Crumeyrolle, S.; Schwarzenboeck, A.; Sellegri, K.; Burkhart, J. F.; Stohl, A.; Gomes, L.; Quennehen, B.; Roberts, G.; Weigel, R.; Roger, J. C.; Villani, P.; Pichon, J. M.; Bourrianne, T.; Laj, P.

    2012-04-01

    Within the frame of the European Aerosol Cloud Climate and Air Quality Interactions (EUCAARI) project the Météo-France aircraft ATR-42 performed 22 research flights, over central Europe and the North Sea during the intensive observation period in May 2008. For the campaign, the ATR-42 was equipped in order to study aerosol physical, chemical and optical properties, as well as cloud microphysics. During the campaign, continental air masses from Eastern and Western Europe were encountered, along with polar and Scandinavian air masses. For the 22 research flights, retroplume analyses along the flight tracks were performed with FLEXPART in order to classify air masses into five sectors of origin which allows for a qualitative evaluation of emission influence on the respective air parcel. In the polluted boundary layer (BL), typical concentrations of particles with diameters larger than 10 nm (N10) are of the order of 5000-6000 cm-3, whereas N10 concentrations of clean air masses were lower than 1300 cm-3. The detection of the largest particle number concentrations occurred in air masses coming from Polar and Scandinavian regions for which an elevated number of nucleation mode (25-28 nm) particles was observed and attributed to new particle formation over open sea. In the free troposphere (FT), typical observed N10 are of the order of 900 cm-3 in polluted air masses and 400-600 cm-3 in clean air masses, respectively. In both layers, the chemical composition of submicron aerosol particles is dominated by organic matter and nitrate in polluted air masses, while, sulphate and ammonium followed by organics dominate the submicron aerosols in clean air masses. The highest CCN/CN ratios were observed within the polar air masses while the CCN concentration values are the highest within the polluted air masses. Within the five air mass sectors defined and the two layers (BL and FT), observations have been distinguished into anticyclonic (first half of May 2008) and cyclonic

  17. Mechanical properties and cellular response of novel electrospun nanofibers for ligament tissue engineering: Effects of orientation and geometry.

    PubMed

    Pauly, Hannah M; Kelly, Daniel J; Popat, Ketul C; Trujillo, Nathan A; Dunne, Nicholas J; McCarthy, Helen O; Haut Donahue, Tammy L

    2016-08-01

    Electrospun nanofibers are a promising material for ligamentous tissue engineering, however weak mechanical properties of fibers to date have limited their clinical usage. The goal of this work was to modify electrospun nanofibers to create a robust structure that mimics the complex hierarchy of native tendons and ligaments. The scaffolds that were fabricated in this study consisted of either random or aligned nanofibers in flat sheets or rolled nanofiber bundles that mimic the size scale of fascicle units in primarily tensile load bearing soft musculoskeletal tissues. Altering nanofiber orientation and geometry significantly affected mechanical properties; most notably aligned nanofiber sheets had the greatest modulus; 125% higher than that of random nanofiber sheets; and 45% higher than aligned nanofiber bundles. Modifying aligned nanofiber sheets to form aligned nanofiber bundles also resulted in approximately 107% higher yield stresses and 140% higher yield strains. The mechanical properties of aligned nanofiber bundles were in the range of the mechanical properties of the native ACL: modulus=158±32MPa, yield stress=57±23MPa and yield strain=0.38±0.08. Adipose derived stem cells cultured on all surfaces remained viable and proliferated extensively over a 7 day culture period and cells elongated on nanofiber bundles. The results of the study suggest that aligned nanofiber bundles may be useful for ligament and tendon tissue engineering based on their mechanical properties and ability to support cell adhesion, proliferation, and elongation.

  18. Supplementation of exogenous adenosine 5'-triphosphate enhances mechanical properties of 3D cell-agarose constructs for cartilage tissue engineering.

    PubMed

    Gadjanski, Ivana; Yodmuang, Supansa; Spiller, Kara; Bhumiratana, Sarindr; Vunjak-Novakovic, Gordana

    2013-10-01

    Formation of tissue-engineered cartilage is greatly enhanced by mechanical stimulation. However, direct mechanical stimulation is not always a suitable method, and the utilization of mechanisms underlying mechanotransduction might allow for a highly effective and less aggressive alternate means of stimulation. In particular, the purinergic, adenosine 5'-triphosphate (ATP)-mediated signaling pathway is strongly implicated in mechanotransduction within the articular cartilage. We investigated the effects of transient and continuous exogenous ATP supplementation on mechanical properties of cartilaginous constructs engineered using bovine chondrocytes and human mesenchymal stem cells (hMSCs) encapsulated in an agarose hydrogel. For both cell types, we have observed significant increases in equilibrium and dynamic compressive moduli after transient ATP treatment applied in the fourth week of cultivation. Continuous ATP treatment over 4 weeks of culture only slightly improved the mechanical properties of the constructs, without major changes in the total glycosaminoglycan (GAG) and collagen content. Structure-function analyses showed that transiently ATP-treated constructs, and in particular those based on hMSCs, had the highest level of correlation between compositional and mechanical properties. Transiently treated groups showed intense staining of the territorial matrix for GAGs and collagen type II. These results indicate that transient ATP treatment can improve functional mechanical properties of cartilaginous constructs based on chondrogenic cells and agarose hydrogels, possibly by improving the structural organization of the bulk phase and territorial extracellular matrix (ECM), that is, by increasing correlation slopes between the content of the ECM components (GAG, collagen) and mechanical properties of the construct.

  19. A comparison of solar energetic particle event timescales with properties of associated coronal mass ejections

    SciTech Connect

    Kahler, S. W.

    2013-06-01

    The dependence of solar energetic proton (SEP) event peak intensities Ip on properties of associated coronal mass ejections (CMEs) has been extensively examined, but the dependence of SEP event timescales is not well known. We define three timescales of 20 MeV SEP events and ask how they are related to speeds v {sub CME} or widths W of their associated CMEs observed by LASCO/SOHO. The timescales of the EPACT/Wind 20 MeV events are TO, the onset time from CME launch to SEP onset; TR, the rise time from onset to half the peak intensity (0.5Ip); and TD, the duration of the SEP intensity above 0.5Ip. This is a statistical study based on 217 SEP-CME events observed during 1996-2008. The large number of SEP events allows us to examine the SEP-CME relationship in five solar-source longitude ranges. In general, we statistically find that TO declines slightly with v {sub CME}, and TR and TD increase with both v {sub CME} and W. TO is inversely correlated with log Ip, as expected from a particle background effect. We discuss the implications of this result and find that a background-independent parameter TO+TR also increases with v {sub CME} and W. The correlations generally fall below the 98% significance level, but there is a significant correlation between v {sub CME} and W which renders interpretation of the timescale results uncertain. We suggest that faster (and wider) CMEs drive shocks and accelerate SEPs over longer times to produce the longer TR and TD SEP timescales.

  20. A Comparison of Solar Energetic Particle Event Timescales with Properties of Associated Coronal Mass Ejections

    NASA Astrophysics Data System (ADS)

    Kahler, S. W.

    2013-06-01

    The dependence of solar energetic proton (SEP) event peak intensities Ip on properties of associated coronal mass ejections (CMEs) has been extensively examined, but the dependence of SEP event timescales is not well known. We define three timescales of 20 MeV SEP events and ask how they are related to speeds v CME or widths W of their associated CMEs observed by LASCO/SOHO. The timescales of the EPACT/Wind 20 MeV events are TO, the onset time from CME launch to SEP onset; TR, the rise time from onset to half the peak intensity (0.5Ip); and TD, the duration of the SEP intensity above 0.5Ip. This is a statistical study based on 217 SEP-CME events observed during 1996-2008. The large number of SEP events allows us to examine the SEP-CME relationship in five solar-source longitude ranges. In general, we statistically find that TO declines slightly with v CME, and TR and TD increase with both v CME and W. TO is inversely correlated with log Ip, as expected from a particle background effect. We discuss the implications of this result and find that a background-independent parameter TO+TR also increases with v CME and W. The correlations generally fall below the 98% significance level, but there is a significant correlation between v CME and W which renders interpretation of the timescale results uncertain. We suggest that faster (and wider) CMEs drive shocks and accelerate SEPs over longer times to produce the longer TR and TD SEP timescales.

  1. Mass distribution and concentrations of negative chemiions in the exhaust of a jet engine: Sulfuric acid concentrations and observation of particle growth

    NASA Astrophysics Data System (ADS)

    Miller, Thomas M.; Ballenthin, John O.; Viggiano, A. A.; Anderson, Bruce E.; Wey, Chowen C.

    Measurements of negative-ion composition and density have been made in the exhaust of a J85-GE-5H turbojet, at ground level, as part of the NASA-EXCAVATE campaign. The mass spectrometer was placed 3 m from the exhaust plane of the engine. Measurements were done as a function of engine power in six steps from idle (50%) to military power (100%). Since the exhaust velocity changes with power, this also corresponds to a time evolution for ion growth. At 100% power most of the ions are HSO 4- with minor amounts of HSO 4-(H 2O) n. With decreasing engine power the degree of hydration increases. In addition, ions with a 139-amu core dominate the spectra at lower engine power. The chemical identity of this ion is unknown. Observation of a small amount of NO 3- core ions in the high-power spectra allows the determination of H 2SO 4 concentrations, which turn out to be a fraction-of-a-percent of the total sulfur in the fuel. Combining the present data with several previous composition measurements allows one to observe ion evolution from bare ions to ions with masses >8000 amu. Ion densities are derived and appear consistent with previous measurements used in modeling studies indicating that ion nucleation is a probable mechanism for volatile aerosol formation.

  2. Neutrino mass

    SciTech Connect

    Robertson, R.G.H.

    1992-01-01

    Despite intensive experimental work since the neutrino's existence was proposed by Pauli 60 years ago, and its first observation by Reines and Cowan almost 40 years ago, the neutrino's fundamental properties remain elusive. Among those properties are the masses of the three known flavors, properties under charge conjugation, parity and time-reversal, and static and dynamic electromagnetic moments. Mass is perhaps the most fundamental, as it constrains the other properties. The present status of the search for neutrino mass is briefly reviewed.

  3. Engine Operating Conditions and Fuel Properties on Pre-Spark Heat Release and SPI Promotion in SI Engines

    SciTech Connect

    Splitter, Derek A; Kaul, Brian C; Szybist, James P; Jatana, Gurneesh S

    2017-01-01

    This work explores the dependence of fuel ignition delay on stochastic pre-ignition (SPI). Findings are based on bulk gas thermodynamic state, where the effects of kinetically controlled bulk gas pre-spark heat release (PSHR) are correlated to SPI tendency and magnitude. Specifically, residual gas and low temperature PSHR chemistry effects and observations are explored, which are found to be indicative of bulk gas conditions required for strong SPI events. Analyzed events range from non-knocking SPI to knocking SPI and even detonation SPI events in excess of 325 bar peak cylinder pressure. The work illustrates that singular SPI event count and magnitude are found to be proportional to PSHR of the bulk gas mixture and residual gas fraction. Cycle-to-cycle variability in trapped residual mass and temperature are found to impose variability in singular SPI event count and magnitude. However, clusters and short lived bursts of multiple SPI events are found to better correlate with fuel-wall interaction. The results highlight the interplay of bulk gas thermodynamics and SPI ignition source, on SPI event magnitude and cluster tendency. Moreover, the results highlight fundamental fuel reactivity and associated hypersensitivity to operating conditions at SPI prone operating conditions.

  4. Compression ignition engine fuel properties of a used sunflower oil-diesel fuel blend

    SciTech Connect

    Oezaktas, T.

    2000-05-01

    Vegetable oils may be used with dilution modification technique as an alternative diesel fuel. In this study, a used sunflower oil-diesel fuel blend (20:80 {nu}/{nu}%) was investigated in a Pancar Motor E-108-type diesel engine to observe engine characteristics and exhaust emission. The effect of the compression ratio on ignition delay characteristics and smoke emissions of blend fuel was determined in this CFR engine. The results of fuel blends were compared with the reference grade No. 2-D diesel fuel.

  5. The ELM Survey. VII. Orbital Properties of Low-Mass White Dwarf Binaries

    NASA Astrophysics Data System (ADS)

    Brown, Warren R.; Gianninas, A.; Kilic, Mukremin; Kenyon, Scott J.; Allende Prieto, Carlos

    2016-02-01

    We present the discovery of 15 extremely low-mass (5\\lt {log}g\\lt 7) white dwarf (WD) candidates, 9 of which are in ultra-compact double-degenerate binaries. Our targeted extremely low-mass Survey sample now includes 76 binaries. The sample has a lognormal distribution of orbital periods with a median period of 5.4 hr. The velocity amplitudes imply that the binary companions have a normal distribution of mass with 0.76 M⊙ mean and 0.25 M⊙ dispersion. Thus extremely low-mass WDs are found in binaries with a typical mass ratio of 1:4. Statistically speaking, 95% of the WD binaries have a total mass below the Chandrasekhar mass, and thus are not type Ia supernova progenitors. Yet half of the observed binaries will merge in less than 6 Gyr due to gravitational wave radiation; probable outcomes include single massive WDs and stable mass transfer AM CVn binaries. Based on observations obtained at the MMT Observatory, a joint facility of the Smithsonian Institution and the University of Arizona.

  6. An Introduction to the Cost of Engineering and Institutional Controls at Brownfield Properties

    EPA Pesticide Factsheets

    This fact sheet introduces and explores the costs of site cleanup and, where cleanup leaves site contamination that restricts reuse, outlines the engineering and institutional controls and their monitoring and maintenance costs over a longer time frame.

  7. Afghanistan Security Forces Fund Phase III-U.S. Army Corps of Engineers Real Property Accountability

    DTIC Science & Technology

    2009-04-14

    None A.1., B.1. Commander, U.S. Army Corps of Engineers, Afghanistan Engineer District None A.1., A.2., B.1., B.2., B.3. ii Table of Contents...requirement for an oxygen supply system at NMH. The NMH phase II contract, awarded on August 1, 2006, included option 0016 to replace the oxygen supply...Proposals (RFP). The Kabul NMH phase II contract file did not document that this planning coordination took place. AED exercised this contract

  8. Molecular isotopic engineering (MIE): industrial manufacture of naproxen of predetermined stable carbon-isotopic compositions for authenticity and security protection and intellectual property considerations

    NASA Astrophysics Data System (ADS)

    Jasper, J. P.; Farina, P.; Pearson, A.; Mezes, P. S.; Sabatelli, A. D.

    2016-05-01

    Molecular Isotopic Engineering (MIE) is the directed stable-isotopic synthesis of chemical products for reasons of product identification and of product security, and also for intellectual property considerations. We report here a generally excellent correspondence between the observed and predicted stable carbon-isotopic (δ13C) results for a successful directed synthesis of racemic mixture from its immediate precursors. The observed results are readily explained by the laws of mass balance and isotope mass balance. Oxygen- and hydrogen isotopic results which require an additional assessment of the effects of O and H exchange, presumably due to interaction with water in the reaction solution, are addressed elsewhere. A previous, cooperative study with the US FDA-DPA showed that individual manufacturers of naproxen could readily be differentiated by their stable-isotopic provenance (δ13C, δ18O, and δD ref. 1). We suggest that MIE can be readily employed in the bio/pharmaceutical industry without alteration of present manufacturing processes other than isotopically selecting and/or monitoring reactants and products.

  9. Windows-based guided data capture software for mass-scale thermophysical and thermochemical property data collection.

    PubMed

    Diky, Vladimir V; Chirico, Robert D; Wilhoit, Randolph C; Dong, Qian; Frenkel, Michael

    2003-01-01

    Guided data capture software (GDC) is described for mass-scale abstraction from the literature of experimental thermophysical and thermochemical property data for organic chemical systems involving one, two, and three components, chemical reactions, and chemical equilibria. Property values are captured with a strictly hierarchical system based upon rigorous application of the thermodynamic constraints of the Gibbs phase rule with full traceability to source documents. Key features of the program and its adherence to scientific principles are described with particular emphasis on data-quality issues, both in terms of data accuracy and database integrity.

  10. Engineering and design properties of thallium-doped sodium iodide and selected properties of sodium-doped cesium iodide

    NASA Technical Reports Server (NTRS)

    Forrest, K.; Haehner, C.; Heslin, T.; Magida, M.; Uber, J.; Freiman, S.; Hicho, G.; Polvani, R.

    1984-01-01

    Mechanical and thermal properties, not available in the literature but necessary to structural design, using thallium doped sodium iodide and sodium doped cesium iodide were determined to be coefficient of linear thermal expansion, thermal conductivity, thermal shock resistance, heat capacity, elastic constants, ultimate strengths, creep, hardness, susceptibility to subcritical crack growth, and ingot variation of strength. These properties were measured for single and polycrystalline materials at room temperature.

  11. Target Capturing Control for Space Robots with Unknown Mass Properties: A Self-Tuning Method Based on Gyros and Cameras.

    PubMed

    Li, Zhenyu; Wang, Bin; Liu, Hong

    2016-08-30

    Satellite capturing with free-floating space robots is still a challenging task due to the non-fixed base and unknown mass property issues. In this paper gyro and eye-in-hand camera data are adopted as an alternative choice for solving this problem. For this improved system, a new modeling approach that reduces the complexity of system control and identification is proposed. With the newly developed model, the space robot is equivalent to a ground-fixed manipulator system. Accordingly, a self-tuning control scheme is applied to handle such a control problem including unknown parameters. To determine the controller parameters, an estimator is designed based on the least-squares technique for identifying the unknown mass properties in real time. The proposed method is tested with a credible 3-dimensional ground verification experimental system, and the experimental results confirm the effectiveness of the proposed control scheme.

  12. Experimental Validation of the Dynamic Inertia Measurement Method to Find the Mass Properties of an Iron Bird Test Article

    NASA Technical Reports Server (NTRS)

    Chin, Alexander W.; Herrera, Claudia Y.; Spivey, Natalie D.; Fladung, William A.; Cloutier, David

    2015-01-01

    The mass properties of an aerospace vehicle are required by multiple disciplines in the analysis and prediction of flight behavior. Pendulum oscillation methods have been developed and employed for almost a century as a means to measure mass properties. However, these oscillation methods are costly, time consuming, and risky. The NASA Armstrong Flight Research Center has been investigating the Dynamic Inertia Measurement, or DIM method as a possible alternative to oscillation methods. The DIM method uses ground test techniques that are already applied to aerospace vehicles when conducting modal surveys. Ground vibration tests would require minimal additional instrumentation and time to apply the DIM method. The DIM method has been validated on smaller test articles, but has not yet been fully proven on large aerospace vehicles.

  13. Target Capturing Control for Space Robots with Unknown Mass Properties: A Self-Tuning Method Based on Gyros and Cameras

    PubMed Central

    Li, Zhenyu; Wang, Bin; Liu, Hong

    2016-01-01

    Satellite capturing with free-floating space robots is still a challenging task due to the non-fixed base and unknown mass property issues. In this paper gyro and eye-in-hand camera data are adopted as an alternative choice for solving this problem. For this improved system, a new modeling approach that reduces the complexity of system control and identification is proposed. With the newly developed model, the space robot is equivalent to a ground-fixed manipulator system. Accordingly, a self-tuning control scheme is applied to handle such a control problem including unknown parameters. To determine the controller parameters, an estimator is designed based on the least-squares technique for identifying the unknown mass properties in real time. The proposed method is tested with a credible 3-dimensional ground verification experimental system, and the experimental results confirm the effectiveness of the proposed control scheme. PMID:27589748

  14. Membrane-Introduction Mass Spectrometry Analysis of Desflurane, Propofol and Fentanyl in Plasma and Cerebrospinal Fluid for Estimation BBB Properties

    PubMed Central

    Cherebillo, Vyacheslav Yu.; Polegaev, Andrei V.

    2015-01-01

    A possibility to use the Membrane-Introduction Mass Spectrometry (MIMS) with membrane separator interface has evolved into a powerful method for measurement of anaesthetic agents absolute concentration in blood plasma and cerebrospinal fluid for the study of blood-brain barrier (BBB) properties. Recent advanced a new membrane material was used for drug concentration measurement in biologic fluids. A hydrophobic membrane was used in the interface to separate anaesthetic agents from biological fluids: inhalational anaesthetic desflurane,hypnotic propofol, analgesic fentanyl. The selective detection of volatile anesthetic agents in blood does not require long-term sample processing before injecting the sample into mass-spectrometer interface, in contrast to chromatographic methods. Mass-spectrometric interface for the measurement of anaesthetic agent concentration in biological fluids (blood plasma and cerebrospinal fluid) is described. Sampling of biological fluids was performed during balanced inhalational (desflurane, fentanyl) anaesthesia and total intravenous (propofol, fentanyl) anaesthesia. PMID:26412969

  15. Measurement of Sedimentary Interbed Hydraulic Properties and Their Hydrologic Influence near the Idaho Nuclear Technology and Engineering Center at the Idaho National Engineering and Environmental Laboratory

    USGS Publications Warehouse

    Perkins, Kim S.

    2003-01-01

    Disposal of wastewater to unlined infiltration ponds near the Idaho Nuclear Technology and Engineering Center (INTEC), formerly known as the Idaho Chemical Processing Plant, at the Idaho National Engineering and Environmental Laboratory (INEEL) has resulted in the formation of perched water bodies in the unsaturated zone (Cecil and others, 1991). The unsaturated zone at INEEL comprises numerous basalt flows interbedded with thinner layers of coarse- to fine-grained sediments and perched ground-water zones exist at various depths associated with massive basalts, basalt-flow contacts, sedimentary interbeds, and sediment-basalt contacts. Perched ground water is believed to result from large infiltration events such as seasonal flow in the Big Lost River and wastewater discharge to infiltration ponds. Evidence from a large-scale tracer experiment conducted in 1999 near the Radioactive Waste Management Complex (RWMC), approximately 13 km from the INTEC, indicates that rapid lateral flow of perched water in the unsaturated zone may be an important factor in contaminant transport at the INEEL (Nimmo and others, 2002b). Because sedimentary interbeds, and possibly baked-zone alterations at sediment-basalt contacts (Cecil and other, 1991) play an important role in the generation of perched water it is important to assess the hydraulic properties of these units.

  16. Impact of mass-loss on the evolution and pre-supernova properties of red supergiants

    NASA Astrophysics Data System (ADS)

    Meynet, G.; Chomienne, V.; Ekström, S.; Georgy, C.; Granada, A.; Groh, J.; Maeder, A.; Eggenberger, P.; Levesque, E.; Massey, P.

    2015-03-01

    Context. The post-main-sequence evolution of massive stars is very sensitive to many parameters of the stellar models. Key parameters are the mixing processes, the metallicity, the mass-loss rate, and the effect of a close companion. Aims: We study the change in the red supergiant (RSG) lifetimes, the tracks in the Hertzsprung-Russel diagram (HRD), the positions in this diagram of the pre-supernova progenitor and the structure of the stars at that time for various mass-loss rates during the RSG phase and for two different initial rotation velocities. Methods: Stellar models were computed with the Geneva code for initial masses between 9 and 25 M⊙ at solar metallicity (Z = 0.014) with 10 times and 25 times the standard mass-loss rates during the RSG phase, with and without rotation. Results: The surface abundances of RSGs are much more sensitive to rotation than to the mass-loss rates during that phase. A change of the RSG mass-loss rate has a strong impact on the RSG lifetimes and in turn on the luminosity function of RSGs. An observed RSG is associated with a model of higher initial mass when models with an enhanced RSG mass-loss rate are used to deduce that mass. At solar metallicity, models with an enhanced mass-loss rate produce significant changes in the populations of blue, yellow, and RSGs. When extended blue loops or blueward excursions are produced by enhanced mass-loss, the models predict that a majority of blue (yellow) supergiants are post-RSG objects. These post-RSG stars are predicted to show much lower surface rotational velocities than similar blue supergiants on their first crossing of the HR gap. Enhanced mass-loss rates during the RSG phase have little impact on the Wolf-Rayet populations. The position in the HRD of the end point of the evolution depends on the mass of the hydrogen envelope. More precisely, whenever at the pre-supernova stage the H-rich envelope contains more than about 5% of the initial mass, the star is a RSG, and whenever

  17. Negative, positive, and infinite mass properties of a rotating electron beam

    SciTech Connect

    French, David M.; Lau, Y. Y.; Gilgenbach, R. M.; Hoff, Brad W.

    2010-09-13

    An electron rotating under a uniform axial magnetic field and a radial electric field exhibits an effective mass that may be negative, positive, or infinite, in response to an azimuthal electric field. This paper reports simulation results that show instability and stability when the effective mass are negative and positive, respectively, depending on the magnitude and orientation of the radial electric field. Thus, the inverted magnetron would have a much faster startup than the conventional magnetron, an important consideration for pulsed operation. When the effective mass is infinite, the electrons hardly respond to an azimuthal ac electric field.

  18. The relationship of conodont biofacies to spatially variable water mass properties in the Late Pennsylvanian Midcontinent Sea

    NASA Astrophysics Data System (ADS)

    Herrmann, Achim D.; Barrick, James E.; Algeo, Thomas J.

    2015-03-01

    Molybdenum and uranium enrichment factors and nitrogen isotopes suggest that an interplay of open ocean upwelling and riverine runoff led to distinct spatial and secular variations in water mass properties within the epicontinental Late Pennsylvanian Midcontinent Sea of North America. In particular, the intensity of continental runoff influenced the flux of bulk organic matter to the sediment. Benthic anoxia appears to have been controlled by the vertical density gradient in the water column associated with continental runoff combined with the advection of basinal water. Anoxic conditions were stronger in proximal (i.e., more shoreward) areas of the Midcontinent Shelf, indicating that anoxia did not develop primarily due to upwelling of nutrient-rich waters along the southern shelf margin, as previously suggested. Changes in water mass redox conditions not only drove authigenic enrichment of redox-sensitive trace elements across the basin but also had a strong effect on the spatial distribution of various conodont taxa. Our analysis suggests that the widely accepted depth-stratification model for the distribution of conodonts is incomplete. Conodont biofacies distributions seem to have been controlled by physicochemical properties of the water mass (e.g., salinity, temperature, nutrients, turbidity, and/or dissolved oxygen levels) that may correspond less directly to water depth. The proximity to terrestrial freshwater influx and the strength of anoxia/euxinia in the subpycnoclinal water mass played significant roles in the spatial and temporal distributions of conodont taxa.

  19. Subaru weak-lensing survey of dark matter subhalos in the Coma cluster: Subhalo mass function and statistical properties

    SciTech Connect

    Okabe, Nobuhiro; Futamase, Toshifumi; Kuroshima, Risa; Kajisawa, Masaru

    2014-04-01

    We present a 4 deg{sup 2} weak gravitational lensing survey of subhalos in the very nearby Coma cluster using the Subaru/Suprime-Cam. The large apparent size of cluster subhalos allows us to measure the mass of 32 subhalos detected in a model-independent manner, down to the order of 10{sup –3} of the virial mass of the cluster. Weak-lensing mass measurements of these shear-selected subhalos enable us to investigate subhalo properties and the correlation between subhalo masses and galaxy luminosities for the first time. The mean distortion profiles stacked over subhalos show a sharply truncated feature which is well-fitted by a Navarro-Frenk-White (NFW) mass model with the truncation radius, as expected due to tidal destruction by the main cluster. We also found that subhalo masses, truncation radii, and mass-to-light ratios decrease toward the cluster center. The subhalo mass function, dn/dln M {sub sub}, in the range of 2 orders of magnitude in mass, is well described by a single power law or a Schechter function. Best-fit power indices of 1.09{sub −0.32}{sup +0.42} for the former model and 0.99{sub −0.23}{sup +0.34} for the latter, are in remarkable agreement with slopes of ∼0.9-1.0 predicted by the cold dark matter paradigm. The tangential distortion signals in the radial range of 0.02-2 h {sup –1} Mpc from the cluster center show a complex structure which is well described by a composition of three mass components of subhalos, the NFW mass distribution as a smooth component of the main cluster, and a lensing model from a large scale structure behind the cluster. Although the lensing signals are 1 order of magnitude lower than those for clusters at z ∼ 0.2, the total signal-to-noise ratio, S/N = 13.3, is comparable, or higher, because the enormous number of background source galaxies compensates for the low lensing efficiency of the nearby cluster.

  20. Optical spectroscopy using mass-separated beams: Nuclear properties of unstable indium and tin isotopes

    NASA Astrophysics Data System (ADS)

    Kuehl, T.; Kirchner, R.; Klepper, O.; Marx, D.; Dinger, U.; Eberz, J.; Huber, G.; Lochmann, H.; Menges, R.; Ulm, G.

    1987-05-01

    Collinear fast-beam laser-spectroscopy has been used to measure the hyperfine structure and isotope shift of several indium and tin isotopes. The related experimental techniques are described, including the preparation of mass-separated beams of neutron-deficient indium and tin isotopes at the GSI on-line mass separator following fusion-evaporation reactions. The deviation of the observed dependence of the charge radii upon the neutron number from the expected behaviour is briefly discussed.

  1. THE EVOLUTION OF THE SOLAR NEBULA I. EVOLUTION OF THE GLOBAL PROPERTIES AND PLANET MASSES

    SciTech Connect

    Jin Liping; Sui Ning E-mail: suining@email.jlu.edu.c

    2010-02-20

    We investigate the formation, structure, and evolution of the solar nebula by including nonuniform viscosity and the mass influx from the gravitational collapse of the molecular cloud core. The calculations are done by using currently accepted viscosity, which is nonuniform, and probable mass influx from star formation theory. In the calculation of the viscosity, we include the effect of magnetorotational instability. The radial distributions of the surface density and other physical quantities of the nebula are significantly different from nebula models with constant alpha viscosity and the models which do not include the mass influx. We find that the nebula starts to form from the inner boundary because of the inside-out collapse and then expands due to viscosity. The surface density is not a monotonic function of the radius like the case of uniform viscosity. There are minimums near 1.5 AU due to nonuniform viscosity. The general shape of the surface density is sustained before the mass influx stops because the mass supply offsets mass loss accreted onto the protosun and provides the mass needed for the nebula expansion. We show that not all protoplanetary disks experience gravitational instability during some periods of their lifetime. We find that the nebula becomes gravitationally unstable in some durations when the angular momentum of the cloud core is high. Our numerical calculations confirm Jin's early suggestion that nonuniform viscosity explains the differences in mass and gas content among Jovian planets. Our calculations of nebular evolution show that the nebula temperature is less than 1200 K. Even in the inner portion of the nebula, refractory material from the molecular cloud may survive and refractory condensates may form.

  2. Carbon nanotubes reinforced chitosan films: mechanical properties and cell response of a novel biomaterial for cardiovascular tissue engineering.

    PubMed

    Kroustalli, A; Zisimopoulou, A E; Koch, S; Rongen, L; Deligianni, D; Diamantouros, S; Athanassiou, G; Kokozidou, M; Mavrilas, D; Jockenhoevel, S

    2013-12-01

    Carbon nanotubes have been proposed as fillers to reinforce polymeric biomaterials for the strengthening of their structural integrity to achieve better biomechanical properties. In this study, a new polymeric composite material was introduced by incorporating various low concentrations of multiwalled carbon nanotubes (MWCNTs) into chitosan (CS), aiming at achieving a novel composite biomaterial with superior mechanical and biological properties compared to neat CS, in order to be used in cardiovascular tissue engineering applications. Both mechanical and biological characteristics in contact with the two relevant cell types (endothelial cells and vascular myofibroblasts) were studied. Regarding the mechanical behavior of MWCNT reinforced CS (MWCNT/CS), 5 and 10 % concentrations of MWCNTs enhanced the mechanical behavior of CS, with that of 5 % exhibiting a superior mechanical strength compared to 10 % concentration and neat CS. Regarding biological properties, MWCNT/CS best supported proliferation of endothelial and myofibroblast cells, MWCNTs and MWCNT/CS caused no apoptosis and were not toxic of the examined cell types. Conclusively, the new material could be suitable for tissue engineering (TE) and particularly for cardiovascular TE applications.

  3. Mass Uncertainty and Application For Space Systems

    NASA Technical Reports Server (NTRS)

    Beech, Geoffrey

    2013-01-01

    Expected development maturity under contract (spec) should correlate with Project/Program Approved MGA Depletion Schedule in Mass Properties Control Plan. If specification NTE, MGA is inclusive of Actual MGA (A5 & A6). If specification is not an NTE Actual MGA (e.g. nominal), then MGA values are reduced by A5 values and A5 is representative of remaining uncertainty. Basic Mass = Engineering Estimate based on design and construction principles with NO embedded margin MGA Mass = Basic Mass * assessed % from approved MGA schedule. Predicted Mass = Basic + MGA. Aggregate MGA % = (Aggregate Predicted - Aggregate Basic) /Aggregate Basic.

  4. PREFACE: 14th International Conference on Metrology and Properties of Engineering Surfaces (Met & Props 2013)

    NASA Astrophysics Data System (ADS)

    Fu, Wei-En

    2014-03-01

    hospitality. It is my privilege and pleasure to welcome you all to the 14th International Conference on Metrology and Properties of Engineering Surfaces here in Taipei. Tom Thomas Halmstad, 1st June 2013 Greetings from Chairman of Local Organizing CommitteeVictor Lin It is the great honor of Center for Measurement Standards (CMS), metrology group of Industrial Technology Research Institute (ITRI), to host the 14th International Conference on Metrology and Properties of Engineering Surfaces (Met & Props 2013) from 17-21 June, 2013, in Taipei, Taiwan. In collaboration with four local universities, National Taiwan University (NTU), National Cheng-Kung University (NCKU), National Taiwan University of Science and Technology (NTST) and National Tsing-Hua University (NTHU), we have spent more than one year to prepare this Conference since the approval by the International Programme Committee (IPC). With the guidance from the IPC, we are able to go through the laborious, but important, process of paper selection and review from more than 100 submissions, and also to maintain the tradition in gathering the high quality and state-of-the-art papers. Finally, more than 65 full papers are collected in the programme (oral and poster), and over 120 surface metrologists from 17 countries (or economies) will attend the Conference. As stated in the preface by Professor Thomas, this series of conferences were founded by Tom and late Professor Ken Stout in the United Kingdom more than thirty years ago. I was lucky to join Ken's research group in Birmingham, and to start my journey over surface metrology in 1989, under the financial support from ITRI. With the encouragement from Professor Liam Blunt and endeavors of my colleagues, we are able to hold the Conference first time in emerging Asia, and to ''carry on the heritage and pave the way to the future'' (a Chinese proverb) in surface metrology. Taiwan is also known as Formosa, from Portuguese Ilha Formosa, which means ''Beautiful Island

  5. Direct measurements of the fundamental properties of low-mass stars and brown dwarfs

    NASA Astrophysics Data System (ADS)

    Dupuy, Trent J.

    2010-10-01

    Detailed theoretical models of stars, developed and observationally tested over the last century, now underlie most of modern astronomy. In contrast, models of lower temperature objects, brown dwarfs and gas giant planets, have only recently been developed and remained largely unconstrained by observations. Despite this lack of empirical validation, these models have become entrenched in many active areas of astronomical research, and thus rigorously testing them is imperative. Dynamical masses from visual binaries are central to this effort, but such measurements have been previously been impeded by observational limitations (ultracool binaries are faint, and their orbital separations are very small). This dissertation presents results from our program to test models using precise dynamical masses (as good as 2%) for ultracool binaries, based on infrared parallaxes, near-infrared spectroscopy, and Keck laser guide star adaptive optics astrometry for a sample of over 30 objects. In just the last 2 years, we have more than tripled the number of ultracool binaries with dynamical masses, extending these measurements to much lower temperatures in previously unexplored areas of parameter space. Our main results are summarized as follows: (1) For most field binaries, based on direct measurements of their luminosities and masses, we find that the temperatures predicted by evolutionary models are discrepant with those derived from fitting the observed spectra with model atmospheres, indicating systematic errors of [approximate]200 K in temperature (or 15%-20% in radius). We have also devised alternative model tests for these systems using their space motion and chromospheric activity to constrain their ages. (2) For the only field binary with an independent age determination from the solar-type primary in its hierarchical triple system (from age-activity-rotation relations), we find that evolutionary models systematically underpredict luminosities by a factor of

  6. Fundamental understanding of matter: an engineering viewpoint

    SciTech Connect

    Cullingford, H.S.; Cort, G.E.

    1980-01-01

    Fundamental understanding of matter is a continuous process that should produce physical data for use by engineers and scientists in their work. Lack of fundamental property data in any engineering endeavor cannot be mitigated by theoretical work that is not confirmed by physical experiments. An engineering viewpoint will be presented to justify the need for understanding of matter. Examples will be given in the energy engineering field to outline the importance of further understanding of material and fluid properties and behavior. Cases will be cited to show the effects of various data bases in energy, mass, and momentum transfer. The status of fundamental data sources will be discussed in terms of data centers, new areas of engineering, and the progress in measurement techniques. Conclusions and recommendations will be outlined to improve the current situation faced by engineers in carrying out their work. 4 figures.

  7. Blue straggler masses from pulsation properties. I. The case of NGC 6541

    SciTech Connect

    Fiorentino, G.; Lanzoni, B.; Dalessandro, E.; Ferraro, F. R.; Marconi, M.

    2014-03-01

    We used high spatial resolution images acquired with the Wide Field Camera 3 on board Hubble Space Telescope to probe the population of variable blue straggler stars (BSSs) in the central region of the poorly studied Galactic globular cluster NGC 6541. The time sampling of the acquired multiwavelength (F390W, F555W, and F814W) data allowed us to discover three WUMa stars and nine SX Phoenicis. Periods, mean magnitudes, and pulsation modes have been derived for the nine SX Phoenicis, and their masses have been estimated by using pulsation equations obtained from linear nonadiabatic models. We found masses in the range 1.0-1.1 M {sub ☉}, with an average value of 1.06 ± 0.09 M {sub ☉} (σ = 0.04), significantly in excess of the cluster main-sequence turn-off mass (∼0.75 M {sub ☉}). A mild trend between mass and luminosity seems also to be present. The computed pulsation masses turn out to be in very good agreement with the predictions of evolutionary tracks for single stars, indicating values in the range ∼1.0-1.2 M {sub ☉} for most of the BSS population, in agreement with what was discussed in a number of previous studies.

  8. Data for the analysis of PolyHIPE scaffolds with tunable mechanical properties for bone tissue engineering.

    PubMed

    Owen, Robert; Sherborne, Colin; Reilly, Gwendolen C; Claeyssens, Frederik

    2015-12-01

    This article presents data related to the research article titled, 'Emulsion templated scaffolds with tunable mechanical properties for bone tissue engineering' (Owen et al., in press) [1]. This data article contains excel files with the results obtained during the mechanical characterisation of 20 acrylate-based PolyHIPE compositions, giving the Young's modulus, ultimate tensile stress and strain at failure for each specimen tested. Also included are the measurements taken to determine the degree of openness (DOO) of each composition, and the data for the cell viability and alkaline phosphatase (ALP) activity on the emulsion templated scaffolds.

  9. Optical properties and ferroelectric engineering of vapor-transport-equilibrated, near-stoichiometric lithium tantalate for frequency conversion

    NASA Astrophysics Data System (ADS)

    Hum, D. S.; Route, R. K.; Miller, G. D.; Kondilenko, V.; Alexandrovski, A.; Huang, J.; Urbanek, K.; Byer, R. L.; Fejer, M. M.

    2007-05-01

    Near-stoichiometric lithium tantalate (SLT) crystals were produced from congruent lithium tantalate by vapor transport equilibration, and several important optical and ferroelectric properties were measured. The effect of vapor transport conditions and surface preparation on reproducible ferroelectric engineering of SLT has been studied. Control of these effects along with dramatic decreases in the sensitivity to photorefractive damage and 532 nm absorption has allowed near-room-temperature generation of 10 W of continuous wave 532 nm radiation by second harmonic generation from 29 W of 1064 nm radiation in a 4 cm long device.

  10. In Vitro Corrosion and Cytocompatibility Properties of Nano-Whisker Hydroxyapatite Coating on Magnesium Alloy for Bone Tissue Engineering Applications

    PubMed Central

    Yang, Huawei; Yan, Xueyu; Ling, Min; Xiong, Zuquan; Ou, Caiwen; Lu, Wei

    2015-01-01

    We report here the successful fabrication of nano-whisker hydroxyapatite (nHA) coatings on Mg alloy by using a simple one-step hydrothermal process in aqueous solution. The nHA coating shows uniform structure and high crystallinity. Results indicate that nHA coating is promising for improving the in vitro corrosion and cytocompatibility properties of Mg-based implants and devices for bone tissue engineering. In addition, the simple hydrothermal deposition method used in the current study is also applicable to substrates with complex shapes or surface geometries. PMID:25789500

  11. Linking the central engine to the jet properties in radio loud AGN

    NASA Astrophysics Data System (ADS)

    Olguín-Iglesias, A.; León-Tavares, J.; Chavushyan, V.; Valtaoja, E.; Añorve, C.; Nilsson, K.; Kotilainen, J.; Tornikoski, M.

    2015-03-01

    We explore the connection between the black hole mass and its relativistic jet for a sample of radio-loud AGN (z < 1), in which the relativistic jet parameters are well estimated by means of long term monitoring with the 14m Metsähovi millimeter wave telescope and the Very Long Base-line Array (VLBA). NIR host galaxy images taken with the NOTCam on the Nordic Optical Telescope (NOT) and retrieved from the 2MASS all-sky survey allowed us to perform a detailed surface brightness decomposition of the host galaxies in our sample and to estimate reliable black hole masses via their bulge luminosities. We present early results on the correlations between black hole mass and the relativistic jet parameters. Our preliminary results suggest that the more massive the black hole is, the faster and the more luminous jet it produces.

  12. Strain properties analysis and wireless collection system of PVDF for structural local health monitoring of civil engineering structures

    NASA Astrophysics Data System (ADS)

    Yu, Yan; Wang, Yang; Dong, Weijie; Jin, Yajing; Ou, Jinping

    2009-07-01

    For large civil engineering structures and base establishments, for example, bridges, super-high buildings, long-span space structures, offshore platforms and pipe systems of water & gas supply, their lives are up to a few decades or centuries. Damaged by environmental loads, fatigue effects, corrosion effects and material aging, these structures experience inevitably such side effects as damage accumulation, resistance reduction and even accidents. The traditional civil structure is a kind of passive one, whose performance and status are unpredictable to a great extent, but the informatics' introduction breaks a new path to obtain the status of the structure, thus it is an important research direction to evaluate and improve reliability of civil structures by the use of monitoring and health diagnosis technique, and this also assures the security of service for civil engineering structures. Smart material structure, originated from the aerospace sector, has been a research hotspot in civil engineering, medicine, shipping, and so on. For structural health monitoring of civil engineering, the research about high-performance sensing unit of smart material structure is very important, and this will possibly push further the development and application of monitoring and health diagnosis techniques. At present, piezoelectric materials are one of the most widely used sensing materials among the research of smart material structures. As one of the piezoelectric materials, PVDF(Polyvinylidene Fluoride)film is widely considered for the advantages of low cost, good mechanical ability, high sensibility, the ability of being easily placed and resistance of corrosion. However, only a few studies exit about building a mature monitoring system using PVDF. In this paper, for the sake of using PVDF for sensing unit for structural local monitoring of civil engineering, the strain sensing properties of PVDF are studied in detail. Firstly, the operating mechanism of PVDF is analyzed

  13. Evaluation of engineering properties for the use of leached brown coal ash in soil covers.

    PubMed

    Mudd, Gavin M; Chakrabarti, Srijib; Kodikara, Jayantha

    2007-01-31

    The need to engineer cover systems for the successful rehabilitation or remediation of a wide variety of solid wastes is increasing. Some common applications include landfills, hazardous waste repositories, or mine tailings dams and waste rock/overburden dumps. The brown coal industry of the Latrobe Valley region of Victoria, Australia, produces significant quantities of coal ash and overburden annually. There are some site-specific acid mine drainage (AMD) issues associated with overburden material. This needs to be addressed both during the operational phase of a project and during rehabilitation. An innovative approach was taken to investigate the potential to use leached brown coal ash in engineered soil covers on this overburden dump. The basis for this is two-fold: first, the ash has favourable physical characteristics for use in cover systems (such as high storage capacity/porosity, moderately low permeability, and an ability to act as a capillary break layer generating minimal leachate or seepage); and second, the leachate from the ash is mildly alkaline (which can help to mitigate and reduce the risk of AMD). This paper will review the engineering issues involved in using leached brown coal ash in designing soil covers for potentially acid-forming overburden dumps. It presents the results of laboratory work investigating the technical feasibility of using leached brown coal ash in engineered solid waste cover systems.

  14. Spatial variability of sedimentary interbed properties near the Idaho Nuclear Technology and Engineering Center at the Idaho National Engineering and Environmental Laboratory, Idaho

    USGS Publications Warehouse

    Winfield, Kari A.

    2003-01-01

    The subsurface at the Idaho National Engineering and Environmental Laboratory (INEEL) is complex, comprised primarily of thick, fractured basalt flows interbedded with thinner sedimentary intervals. The unsaturated zone can be as thick as 200 m in the southwestern part of the INEEL. The Vadose Zone Research Park (VZRP), located approximately 10 km southwest of the Idaho Nuclear Technology and Engineering Center (INTEC), was established in 2001 to study the subsurface of a relatively undisturbed part of the INEEL. Waste percolation ponds for the INTEC were relocated to the VZRP due to concerns that perched water within the vadose zone under the original infiltration ponds (located immediately south of the INTEC) could contribute to migration of contaminants to the Snake River Plain aquifer. Knowledge of the spatial distribution of texture and hydraulic properties is important for developing a better understanding of subsurface flow processes within the interbeds, for example, by identifying low permeability layers that could lead to the formation of perched ground-water zones. Because particle-size distributions are easier to measure than hydraulic properties, particle size serves as an analog for determining how the unsaturated hydraulic properties vary both vertically within particular interbeds and laterally within the VZRP. As part of the characterization program for the subsurface at the VZRP, unsaturated and saturated hydraulic properties were measured on 10 core samples from six boreholes. Bulk properties, including particle size, bulk density, particle density, and specific surface area, were determined on material from the same depth intervals as the core samples, with an additional 66 particle- size distributions measured on bulk samples from the same boreholes. From lithologic logs of the 32 boreholes at the VZRP, three relatively thick interbeds (in places up to 10 m thick) were identified at depths of 35, 45, and 55 m below land surface. The 35-m

  15. Improving the moisturizing properties of collagen film by surface grafting of chondroitin sulfate for corneal tissue engineering.

    PubMed

    Liu, Yang; Lv, Huilin; Ren, Li; Xue, Guanhua; Wang, Yingjun

    2016-01-01

    Cornea disease is the second cause of blindness and keratoplasty is the most commonly performed option for visual rehabilitation of patients with corneal blindness. However, the clinical treatment has been drastically limited due to a severe shortage of high-quality donor corneas. Although collagen film with outstanding biocompatibility has promising application in corneal tissue engineering, the moisturizing properties of collagen-based materials must be further improved to satisfy the requirements of clinical applications. This paper describes a novel collagen-based film with high moisture capacity reinforced by surface grafting of chondroitin sulfate. The collagen-chondroitin sulfate (abbreviated as Col-CS) film was analyzed by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy and its hydrophilic property, moisture retention, optical property, and mechanical performance had been tested. The moisture-retaining capacity is found to be improved with the introduction of chondroitin sulfate, and the Col-CS membrane performs better mechanical properties than the collagen film. Moreover, the modified film proves excellent biocompatibility for the proliferation of human corneal epithelial cells in vitro. This Col-CS film with good moisturizing properties can reduce the risk of xerophthalmia and is expected to increase the implant success rate in clinic patients with corneal defects.

  16. Tailoring chitosan/collagen scaffolds for tissue engineering: Effect of composition and different crosslinking agents on scaffold properties.

    PubMed

    Martínez, A; Blanco, M D; Davidenko, N; Cameron, R E

    2015-11-05

    Chitosan/collagen (Chit/Col) blends have demonstrated great potential for use in tissue engineering (TE) applications. However, there exists a lack of detailed study on the influence of important design parameters (i.e, component ratio or crosslinking methods) on the essential properties of the scaffolds (morphology, mechanical stiffness, swelling, degradation and cytotoxicity). This work entailed a systematic study of these essential properties of three Chit/Col compositions, covering a wide range of component ratios and using different crosslinking methods. Our results showed the possibility of tailoring these properties by changing component ratios, since different interactions occurred between Chit/Col: samples with Chit-enriched compositions showed a hydrogen-bonding type complex (HC), whereas a self-crosslinking phenomenon was induced in Col-enriched scaffolds. Additionally, material and biological properties of the resultant matrices were further adjusted and tuned by changing crosslinking conditions. In such way, we obtained a wide range of scaffolds whose properties were tailored to meet specific needs of TE applications.

  17. Precision Mass Property Measurements Using a Five-Wire Torsion Pendulum

    NASA Technical Reports Server (NTRS)

    Swank, Aaron J.

    2012-01-01

    A method for measuring the moment of inertia of an object using a five-wire torsion pendulum design is described here. Typical moment of inertia measurement devices are capable of 1 part in 10(exp 3) accuracy and current state of the art techniques have capabilities of about one part in 10(exp 4). The five-wire apparatus design shows the prospect of improving on current state of the art. Current measurements using a laboratory prototype indicate a moment of inertia measurement precision better than a part in 10(exp 4). In addition, the apparatus is shown to be capable of measuring the mass center offset from the geometric center. Typical mass center measurement devices exhibit a measurement precision up to approximately 1 micrometer. Although the five-wire pendulum was not originally designed for mass center measurements, preliminary results indicate an apparatus with a similar design may have the potential of achieving state of the art precision.

  18. Stellar and Circumstellar Properties of Low-Mass, Young, Subarcsecond Binaries

    NASA Astrophysics Data System (ADS)

    Bruhns, Sara; Prato, L. A.

    2014-01-01

    We present a study of the stellar and circumstellar characteristics of close (< 1''), young (< 2 to 3 Myr), low-mass (<1 solar mass) binary stars in the Taurus star forming region. Low-resolution (R ~ 2000) spectra were taken in the K-band using adaptive optics to separate the observations for each component and identify the individual spectral types, extinction, and K-band excess. Combining these data with stellar luminosities allows us to estimate the stellar masses and ages. We also measured equivalent widths of the hydrogen Brackett gamma line in order to estimate the strength of gas accretion. We obtained spectra for six binary systems with separations from 1'' down to 0.3''. In the CZ Tau binary we found that the fainter secondary star spectrum appears to be of earlier spectral type than the primary; we speculate on the origin of this inversion.

  19. Application for managing model-based material properties for simulation-based engineering

    DOEpatents

    Hoffman, Edward L.

    2009-03-03

    An application for generating a property set associated with a constitutive model of a material includes a first program module adapted to receive test data associated with the material and to extract loading conditions from the test data. A material model driver is adapted to receive the loading conditions and a property set and operable in response to the loading conditions and the property set to generate a model response for the material. A numerical optimization module is adapted to receive the test data and the model response and operable in response to the test data and the model response to generate the property set.

  20. Federal Real Property: Corps of Engineers Needs to Improve the Reliability of Its Real Property Disposal Data

    DTIC Science & Technology

    2008-05-01

    Management Information System (REMIS) for recording its civil works inventory. GAO was asked to determine whether REMIS could provide reliable information on the Corps’ civil works land disposals from fiscal years 1996 through 2006. GAO s work involved comparison analyses of REMIS disposal data and other Corps reported disposal data, reviews of Corps’ real property policies and guidance, and interviews with Corps officials at headquarters, three divisions, four districts, and the Real Estate Systems National Center (RESNC), which manages

  1. Hybrid metal-coordinate transient networks: using bio-inspired building blocks to engineer the mechanical properties of physical hydrogels

    NASA Astrophysics Data System (ADS)

    Grindy, Scott; Barrett, Devin; Messersmith, Phillip; Holten-Andersen, Niels

    2014-03-01

    Recently, metal-coordinate complex crosslinks have been suggested to contribute to the self-healing properties of mussel byssi. Two specific amino acid derivatives - 3,4 dihydroxy-L-phenylalanine (dopa) and histidine (his) - are known to form coordinate complexes with trivalent and divalent ions (respectively) in aqueous solutions. We show here that, by functionalizing poly(ethylene glycol) polymers with dopa and his we are (1) able to characterize the fundamental kinetics and energetics of each specific metal-ligand pair using small amplitude oscillatory shear rheology and (2) create hybrid networks using various mixtures of metals and ligands. From this information, we can design gels with specific target mechanical properties by tailoring the amounts and types of metal-ligand crosslinks present in the gel network, resulting in the ability to engineer the mechanical relaxation spectrum. This work provides basic understanding necessary to intelligently design materials which incorporate metal-ligand crosslinks in more complex architectures.

  2. TIGHT CORRELATIONS BETWEEN MASSIVE GALAXY STRUCTURAL PROPERTIES AND DYNAMICS: THE MASS FUNDAMENTAL PLANE WAS IN PLACE BY z ∼ 2

    SciTech Connect

    Bezanson, Rachel; Van Dokkum, Pieter G.; Leja, Joel; Van de Sande, Jesse; Franx, Marijn; Kriek, Mariska

    2013-12-20

    The fundamental plane (FP) is an empirical relation between the size, surface brightness, and velocity dispersion of early-type galaxies. This relation has been studied extensively for early-type galaxies in the local universe to constrain galaxy formation mechanisms. The evolution of the zero point of this plane has been extended to high redshifts to study the luminosity evolution of massive galaxies, under the assumption of structural homology. In this work, we assess this assumption by replacing surface brightness with stellar mass density and present the evolution of the ''mass FP'' for massive, quiescent galaxies since z ∼ 2. By accounting for stellar populations, we thereby isolate and trace structural and dynamical evolution. Despite the observed dramatic evolution in the sizes and morphologies of massive galaxies since z ∼ 3, we find that quiescent galaxies lie on the mass FP out to z ∼ 2. In contrast with ∼1.4 dex evolution in the luminosity FP, average residuals from the z ∼ 0 mass FP are less than ∼0.15 dex since z ∼ 2. Assuming the Hyde and Bernardi mass FP slope, we find that this minimal offset scales as (1 + z){sup –0.095} {sup ±} {sup 0.043}. This result lends credence to previous studies that derived luminosity evolution from the FP. Therefore, despite their compact sizes and suggestions that massive galaxies are more disk-like at z ∼ 2, the relationship between their dynamics and structural properties are consistent with local early-type galaxies. Finally, we find no strong evidence for a tilt of the mass FP relative to the virial plane, but emphasize the need for full models including selection biases to fully investigate this issue.

  3. Systematic studies of the mass spectrometric properties of alkaline earth metal cationized amino acids and peptides

    NASA Astrophysics Data System (ADS)

    Küjckelmann, Ulrich; Müller, Dietrich; Weber, Carsten

    1997-07-01

    The results of a systematic study of the gas phase interactions of α-amino acids and peptides (4-15 amino acids) with alkaline earth metals, observed with mass spectrometric techniques, are presented. Furthermore, a model for the cationization with calcium at the C-terminal amino acid arginine in rotaviral polypeptides is presented.

  4. Three dimensional simulation of nucleate boiling heat and mass transfer in cooling passages of internal combustion engines

    NASA Astrophysics Data System (ADS)

    Mehdipour, R.; Baniamerian, Z.; Delauré, Y.

    2016-05-01

    An accurate knowledge of heat transfer and temperature distribution in vehicle engines is essential to have a good management of heat transfer performance in combustion engines. This may be achieved by numerical simulation of flow through the engine cooling passages; but the task becomes particularly challenging when boiling occurs. Neglecting two phase flow processes in the simulation would however result in significant inaccuracy in the predictions. In this study a three dimensional numerical model is proposed using Fluent 6.3 to simulate heat transfer of fluid flowing through channels of conventional size. Results of the present theoretical and numerical model are then compared with some empirical results. For high fluid flow velocities, departure between experimental and numerical results is about 9 %, while for lower velocity conditions, the model inaccuracy increases to 18 %. One of the outstanding capabilities of the present model, beside its ability to simulate two phase fluid flow and heat transfer in three dimensions, is the prediction of the location of bubble formation and condensation which can be a key issue in the evaluation of the engine performance and thermal stresses.

  5. Correlation of rocket propulsion fuel properties with chemical composition using comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry followed by partial least squares regression analysis.

    PubMed

    Kehimkar, Benjamin; Hoggard, Jamin C; Marney, Luke C; Billingsley, Matthew C; Fraga, Carlos G; Bruno, Thomas J; Synovec, Robert E

    2014-01-31

    There is an increased need to more fully assess and control the composition of kerosene-based rocket propulsion fuels such as RP-1. In particular, it is critical to make better quantitative connections among the following three attributes: fuel performance (thermal stability, sooting propensity, engine specific impulse, etc.), fuel properties (such as flash point, density, kinematic viscosity, net heat of combustion, and hydrogen content), and the chemical composition of a given fuel, i.e., amounts of specific chemical compounds and compound classes present in a fuel as a result of feedstock blending and/or processing. Recent efforts in predicting fuel chemical and physical behavior through modeling put greater emphasis on attaining detailed and accurate fuel properties and fuel composition information. Often, one-dimensional gas chromatography (GC) combined with mass spectrometry (MS) is employed to provide chemical composition information. Building on approaches that used GC-MS, but to glean substantially more chemical information from these complex fuels, we recently studied the use of comprehensive two dimensional (2D) gas chromatography combined with time-of-flight mass spectrometry (GC×GC-TOFMS) using a "reversed column" format: RTX-wax column for the first dimension, and a RTX-1 column for the second dimension. In this report, by applying chemometric data analysis, specifically partial least-squares (PLS) regression analysis, we are able to readily model (and correlate) the chemical compositional information provided by use of GC×GC-TOFMS to RP-1 fuel property information such as density, kinematic viscosity, net heat of combustion, and so on. Furthermore, we readily identified compounds that contribute significantly to measured differences in fuel properties based on results from the PLS models. We anticipate this new chemical analysis strategy will have broad implications for the development of high fidelity composition-property models, leading to an

  6. An anisotropically and heterogeneously aligned patterned electrospun scaffold with tailored mechanical property and improved bioactivity for vascular tissue engineering.

    PubMed

    Xu, He; Li, Haiyan; Ke, Qinfei; Chang, Jiang

    2015-04-29

    The development of vascular scaffolds with controlled mechanical properties and stimulatory effects on biological activities of endothelial cells still remains a significant challenge to vascular tissue engineering. In this work, we reported an innovative approach to prepare a new type of vascular scaffolds with anisotropically and heterogeneously aligned patterns using electrospinning technique with unique wire spring templates, and further investigated the structural effects of the patterned electrospun scaffolds on mechanical properties and angiogenic differentiation of human umbilical vein endothelial cells (HUVECs). Results showed that anisotropically aligned patterned nanofibrous structure was obtained by depositing nanofibers on template in a structurally different manner, one part of nanofibers densely deposited on the embossments of wire spring and formed cylindrical-like structures in the transverse direction, while others loosely suspended and aligned along the longitudinal direction, forming a three-dimensional porous microstructure. We further found that such structures could efficiently control the mechanical properties of electrospun vascular scaffolds in both longitudinal and transverse directions by altering the interval distances between the embossments of patterned scaffolds. When HUVECs were cultured on scaffolds with different microstructures, the patterned scaffolds distinctively promoted adhesion of HUVECs at early stage and proliferation during the culture period. Most importantly, cells experienced a large shape change associated with cell cytoskeleton and nuclei remodeling, leading to a stimulatory effect on angiogenesis differentiation of HUVECs by the patterned microstructures of electrospun scaffolds, and the scaffolds with larger distances of intervals showed a higher stimulatory effect. These results suggest that electrospun scaffolds with the anisotropically and heterogeneously aligned patterns, which could efficiently control the

  7. C IV emission-line properties and systematic trends in quasar black hole mass estimates

    NASA Astrophysics Data System (ADS)

    Coatman, Liam; Hewett, Paul C.; Banerji, Manda; Richards, Gordon T.

    2016-09-01

    Black hole masses are crucial to understanding the physics of the connection between quasars and their host galaxies and measuring cosmic black hole-growth. At high redshift, z ≳ 2.1, black hole masses are normally derived using the velocity width of the C IV λ λ1548, 1550 broad emission line, based on the assumption that the observed velocity widths arise from virial-induced motions. In many quasars, the C IV emission line exhibits significant blue asymmetries (`blueshifts') with the line centroid displaced by up to thousands of km s-1 to the blue. These blueshifts almost certainly signal the presence of strong outflows, most likely originating in a disc wind. We have obtained near-infrared spectra, including the Hα λ6565 emission line, for 19 luminous (LBol = 46.5-47.5 erg s-1) Sloan Digital Sky Survey quasars, at redshifts 2 < z < 2.7, with C IV emission lines spanning the full range of blueshifts present in the population. A strong correlation between C IV velocity width and blueshift is found and, at large blueshifts, >2000 km s-1, the velocity widths appear to be dominated by non-virial motions. Black hole masses, based on the full width at half-maximum of the C IV emission line, can be overestimated by a factor of 5 at large blueshifts. A larger sample of quasar spectra with both C IV and H β, or Hα, emission lines will allow quantitative corrections to C IV-based black hole masses as a function of blueshift to be derived. We find that quasars with large C IV blueshifts possess high Eddington luminosity ratios and that the fraction of high-blueshift quasars in a flux-limited sample is enhanced by a factor of approximately 4 relative to a sample limited by black hole mass.

  8. Fuels for Advanced Combustion Engines Research Diesel Fuels: Analysis of Physical and Chemical Properties

    SciTech Connect

    Gallant, Tom; Franz, Jim; Alnajjar, Mikhail; Storey, John Morse; Lewis Sr, Samuel Arthur; Sluder, Scott; Cannella, William C; Fairbridge, Craig; Hager, Darcy; Dettman, Heather; Luecke, Jon; Ratcliff, Matthew A.; Zigler, Brad

    2009-01-01

    The CRC Fuels for Advanced Combustion Engines working group has worked to identify a matrix of research diesel fuels for use in advanced combustion research applications. Nine fuels were specified and formulated to investigate the effects of cetane number aromatic content and 90% distillation fraction. Standard ASTM analyses were performed on the fuels as well as GC/MS and /u1H//u1/u3C NMR analyses and thermodynamic characterizations. Details of the actual results of the fuel formulations compared with the design values are presented, as well as results from standard analyses, such as heating value, viscosity and density. Cetane number characterizations were accomplished by using both the engine method and the Ignition Quality Tester (IQT/sT) apparatus.

  9. Magnetic properties of the ALS (Advanced Light Source) booster synchrotron engineering model magnets

    SciTech Connect

    Keller, R.; Green, M.I.; Hoyer, E.; Koo, Y.M.; Luchini, K.; Marks, S.; Milburn, J.; Nelson, D.H.

    1989-03-01

    The Advanced Light Source (ALS) at Lawrence Berkeley Laboratory is designed to be a third-generation electron storage ring producing high-brightness VUV and X-ray radiation from wiggler and undulator insertion devices. Engineering models of all lattice magnets that are to be installed in the storage ring and its booster synchrotron have been built and are being tested to verify their performance. This paper is concerned with the magnets that form the booster lattice: dipoles, quadrupoles, sextupoles, and corrector dipoles (steerers). After a brief outline of measurement techniques and equipment, the major design parameters of these magnets are listed. Measured effective lengths and multipole field errors are then given for each type. All engineering models meet the specifications, and tracking studies including the measured systematic field errors show acceptable performance of the booster synchrotron; hence the designs are qualified for production. 3 refs., 7 figs., 4 tabs.

  10. Chemical and toxicological properties of emissions from CNG transit buses equipped with three-way catalysts compared to lean-burn engines and oxidation catalyst technologies

    NASA Astrophysics Data System (ADS)

    Yoon, Seungju; Hu, Shaohua; Kado, Norman Y.; Thiruvengadam, Arvind; Collins, John F.; Gautam, Mridul; Herner, Jorn D.; Ayala, Alberto

    2014-02-01

    Chemical and toxicological properties of emissions from compressed natural gas (CNG) fueled transit buses with stoichiometric combustion engines and three-way catalyst (TWC) exhaust control systems were measured using a chassis dynamometer testing facility and compared to the data from earlier CNG engine and exhaust control technologies. Gaseous and particulate matter emissions from buses with stoichiometric engines and TWC were significantly lower than the emissions from buses with lean-burn engines. Carbonyls and volatile organic compounds (VOCs) from buses with stoichiometric engines and TWC were lower by more than 99% compared to buses with lean-burn engines. Elemental and organic carbons (EC and OC), polycyclic aromatic hydrocarbons (PAHs), and trace elements from buses with stoichiometric engines and TWC were effectively controlled and significantly lower than the emissions from buses with lean-burn engines. Potential mutagenicity measured using a microsuspension modification of the Salmonella/microsome assay was lower by more than 99% for buses with stoichiometric engines and TWC, compared to buses with lean-burn engines and OxC.

  11. Ecological Engineering Approaches to Improve Hydraulic Properties of Infiltration Basins Designed for Groundwater Recharge.

    PubMed

    Gette-Bouvarot, Morgane; Volatier, Laurence; Lassabatere, Laurent; Lemoine, Damien; Simon, Laurent; Delolme, Cécile; Mermillod-Blondin, Florian

    2015-08-18

    Infiltration systems are increasingly used in urban areas for groundwater recharge. The reduction of sediment permeability by physical and/or biological processes is a major problem in management of infiltration systems often requiring expensive engineering operations for hydraulic performance maintenance. To reduce these costs and for the sake of sustainable development, we proposed to evaluate the ability of ecological engineering approaches to reduce the biological clogging of infiltration basins. A 36-day field-scale experiment using enclosures was performed to test the influences of abiotic (light reduction by shading) and biotic (introduction of the macrophyte Vallisneria spiralis (L.) or the gastropod Viviparus viviparus (Linnaeus, 1758)) treatments to limit benthic biofilm biomass and to maintain or even increase hydraulic performances. We coupled biological characterization of sediment (algal biomass, bacterial abundance, total organic carbon, total nitrogen, microbial enzymatic activity, photosynthetic activity, and photosystem II efficiency) with hydraulic conductivity measurements to assess the effects of treatments on sediment permeability. The grazer Viviparus viviparus significantly reduced benthic biofilm biomass and enhanced hydraulic conductivity. The other treatments did not produce significant changes in hydraulic conductivity although Vallisneria spiralis affected photosynthetic activity of biofilm. Finally, our results obtained with Viviparus viviparus are promising for the development of ecological engineering solutions to prevent biological fouling in infiltration systems.

  12. Metabolic engineering of β-carotene in orange fruit increases its in vivo antioxidant properties.

    PubMed

    Pons, Elsa; Alquézar, Berta; Rodríguez, Ana; Martorell, Patricia; Genovés, Salvador; Ramón, Daniel; Rodrigo, María Jesús; Zacarías, Lorenzo; Peña, Leandro

    2014-01-01

    Orange is a major crop and an important source of health-promoting bioactive compounds. Increasing the levels of specific antioxidants in orange fruit through metabolic engineering could strengthen the fruit's health benefits. In this work, we have afforded enhancing the β-carotene content of orange fruit through blocking by RNA interference the expression of an endogenous β-carotene hydroxylase gene (Csβ-CHX) that is involved in the conversion of β-carotene into xanthophylls. Additionally, we have simultaneously overexpressed a key regulator gene of flowering transition, the FLOWERING LOCUS T from sweet orange (CsFT), in the transgenic juvenile plants, which allowed us to obtain fruit in an extremely short period of time. Silencing the Csβ-CHX gene resulted in oranges with a deep yellow ('golden') phenotype and significant increases (up to 36-fold) in β-carotene content in the pulp. The capacity of β-carotene-enriched oranges for protection against oxidative stress in vivo was assessed using Caenorhabditis elegans as experimental animal model. Golden oranges induced a 20% higher antioxidant effect than the isogenic control. This is the first example of the successful metabolic engineering of the β-carotene content (or the content of any other phytonutrient) in oranges and demonstrates the potential of genetic engineering for the nutritional enhancement of fruit tree crops.

  13. Mechanical properties of completely autologous human tissue engineered blood vessels compared to human saphenous vein and mammary artery

    PubMed Central

    Konig, Gerhardt; McAllister, Todd N; Dusserre, Nathalie; Garrido, Sergio A; Iyican, Corey; Marini, Alicia; Fiorillo, Alex; Avila, Hernan; Wystrychowski, Wojciech; Zagalski, Krzysztof; Maruszewski, Marcin; Jones, Alyce Linthurst; Cierpka, Lech; de la Fuente, Luis M; L’Heureux, Nicolas

    2009-01-01

    We have previously reported initial clinical feasibility with our small diameter tissue engineered blood vessel (TEBV). Here we present in vitro results of the mechanical properties of the TEBVs of the first 25 patients enrolled in an arterio-venous (A-V) shunt safety trial, and compare these properties with those of risk-matched human vein and artery. TEBV average burst pressures (3,490 +/− 892 mmHg, n=230) were higher than native saphenous vein (SV) (1,599 +/− 877 mmHg, n=7), and not significantly different than native internal mammary artery (IMA) (3,196 +/− 1,264 mmHg, n=16). Suture retention strength for the TEBVs (152 +/− 50 gmf) was also not significantly different than IMA (138 +/− 50 gmf). Compliance for the TEBVs prior to implantation (3.4 +/− 1.6 %/100 mmHg) was lower than IMA (11.5 +/− 3.9 %/100 mmHg). By 6 months post-implant, the TEBV compliance (8.8 +/− 4.2 %/100 mmHg, n=5) had increased to values comparable to IMA, and showed no evidence of dilation or aneurysm formation. With clinical time points beyond 21 months as an A-V shunt without intervention, the mechanical tests and subsequent lot release criteria reported here would seem appropriate minimum standards for clinical use of tissue engineered vessels. PMID:19111338

  14. A Novel High Mechanical Property PLGA Composite Matrix Loaded with Nanodiamond-Phospholipid Compound for Bone Tissue Engineering.

    PubMed

    Zhang, Fan; Song, Qingxin; Huang, Xuan; Li, Fengning; Wang, Kun; Tang, Yixing; Hou, Canglong; Shen, Hongxing

    2016-01-20

    A potential bone tissue engineering material was produced from a biodegradable polymer, poly(lactic-co-glycolic acid) (PLGA), loaded with nanodiamond phospholipid compound (NDPC) via physical mixing. On the basis of hydrophobic effects and physical absorption, we modified the original hydrophilic surface of the nanodiamond (NDs) with phospholipids to be amphipathic, forming a typical core-shell structure. The ND-phospholipid weight ratio was optimized to generate sample NDPC50 (i.e., ND-phospholipid weight ratio of 100:50), and NDPC50 was able to be dispersed in a PLGA matrix at up to 20 wt %. Compared to a pure PLGA matrix, the introduction of 10 wt % of NDPC (i.e., sample NDPC50-PF10) resulted in a significant improvement in the material's mechanical and surface properties, including a decrease in the water contact angle from 80 to 55°, an approximately 100% increase in the Young's modulus, and an approximate 550% increase in hardness, thus closely resembling that of human cortical bone. As a novel matrix supporting human osteoblast (hFOB1.19) growth, NDPC50-PFs with different amounts of NDPC50 demonstrated no negative effects on cell proliferation and osteogenic differentiation. Furthermore, we focused on the behaviors of NDPC-PFs implanted into mice for 8 weeks and found that NDPC-PFs induced acceptable immune response and can reduce the rapid biodegradation of PLGA matrix. Our results represent the first in vivo research on ND (or NDPC) as nanofillers in a polymer matrix for bone tissue engineering. The high mechanical properties, good in vitro and in vivo biocompatibility, and increased mineralization capability suggest that biodegradable PLGA composite matrices loaded with NDPC may potentially be useful for a variety of biomedical applications, especially bone tissue engineering.

  15. A photochemical crosslinking technology for tissue engineering: enhancement of the physico-chemical properties of collagen-based scaffolds

    NASA Astrophysics Data System (ADS)

    Chan, Barbara P.

    2005-04-01

    Collagen gel is a natural biomaterial commonly used in tissue engineering because of its close resemblance to nature, negligible immunogenecity and excellent biocompatibility. However, unprocessed collagen gel is mechanically weak, highly water binding and vulnerable to chemical and enzymatic attacks that limits its use in tissue engineering in particular tissues for weight-bearing purposes. The current project aimed to strengthen and stabilize collagen scaffolds using a photochemical crosslinking technique. Photochemical crosslinking is rapid, efficient, non-thermal and does not involve toxic chemicals, comparing with other crosslinking methods such as glutaraldehyde and gamma irradiation. Collagen scaffolds were fabricated using rat-tail tendon collagen. An argon laser was used to process the collagen gel after equilibrating with a photosensitizing reagent. Scanning electronic microscope was used to characterize the surface and cross-sectional morphology of the membranes. Physico-chemical properties of the collagen scaffolds such as water-binding capacity, mechanical properties and thermostability were studied. Photochemical crosslinking significantly reduced the water-binding capacity, a parameter inversely proportional to the extent of crosslinking, of collagen scaffolds. Photochemical crosslinking also significantly increased the ultimate stress and tangent modulus at 90% of the rupture strain of the collagen scaffolds. Differential scanning calorimetry analysis showed a significantly higher shrinkage temperature and absence of the denaturation peak during the thermoscan comparing with the controls. This means greater thermostability in the photochemically crosslinked collagen scaffolds. This study demonstrates that the photochemical crosslinking technology is able to enhance the physicochemical propterties of collagen scaffolds by strengthening, stabilizing and controlling the swelling ratio of the collagen scaffolds so as to enable their use for tissue

  16. Additively manufactured metallic porous biomaterials based on minimal surfaces: A unique combination of topological, mechanical, and mass transport properties.

    PubMed

    Bobbert, F S L; Lietaert, K; Eftekhari, A A; Pouran, B; Ahmadi, S M; Weinans, H; Zadpoor, A A

    2017-02-16

    Porous biomaterials that simultaneously mimic the topological, mechanical, and mass transport properties of bone are in great demand but are rarely found in the literature. In this study, we rationally designed and additively manufactured (AM) porous metallic biomaterials based on four different types of triply periodic minimal surfaces (TPMS) that mimic the properties of bone to an unprecedented level of multi-physics detail. Sixteen different types of porous biomaterials were rationally designed and fabricated using selective laser melting (SLM) from a titanium alloy (Ti-6Al-4V). The topology, quasi-static mechanical properties, fatigue resistance, and permeability of the developed biomaterials were then characterized. In terms of topology, the biomaterials resembled the morphological properties of trabecular bone including mean surface curvatures close to zero. The biomaterials showed a favorable but rare combination of relatively low elastic properties in the range of those observed for trabecular bone and high yield strengths exceeding those reported for cortical bone. This combination allows for simultaneously avoiding stress shielding, while providing ample mechanical support for bone tissue regeneration and osseointegration. Furthermore, as opposed to other AM porous biomaterials developed to date for which the fatigue endurance limit has been found to be ≈20% of their yield (or plateau) stress, some of the biomaterials developed in the current study show extremely high fatigue resistance with endurance limits up to 60% of their yield stress. It was also found that the permeability values measured for the developed biomaterials were in the range of values reported for trabecular bone. In summary, the developed porous metallic biomaterials based on TPMS mimic the topological, mechanical, and physical properties of trabecular bone to a great degree. These properties make them potential candidates to be applied as parts of orthopedic implants and/or as bone

  17. Evolutionary and pulsational properties of low-mass white dwarf stars with oxygen cores resulting from close binary evolution

    NASA Astrophysics Data System (ADS)

    Althaus, L. G.; Córsico, A. H.; Gautschy, A.; Han, Z.; Serenelli, A. M.; Panei, J. A.

    2004-01-01

    The present work is designed to explore the evolutionary and pulsational properties of low-mass white dwarfs with carbon/oxygen cores. In particular, we follow the evolution of a 0.33-Msolar white dwarf remnant in a self-consistent way with the predictions of nuclear burning, element diffusion and the history of the white dwarf progenitor. Attention is focused on the occurrence of hydrogen shell flashes induced by diffusion processes during cooling phases. The evolutionary stages prior to the white dwarf formation are also fully accounted for by computing the conservative binary evolution of an initially 2.5-Msolar Population I star with a 1.25-Msolar companion, and with period Pi= 3 d. Evolution is followed down to the domain of the ZZ Ceti stars on the white dwarf cooling branch. We find that chemical diffusion induces the occurrence of an additional hydrogen thermonuclear flash, which leads to stellar models with thin hydrogen envelopes. As a result, a fast cooling is encountered at advanced stages of evolution. In addition, we explore the adiabatic pulsational properties of the resulting white dwarf models. As compared with their helium-core counterparts, low-mass oxygen-core white dwarfs are characterized by a pulsational spectrum much more featured, an aspect which could eventually be used for distinguishing both types of stars, if low-mass white dwarfs were in fact found to pulsate as ZZ Ceti-type variables. Finally, we perform a non-adiabatic pulsational analysis on the resulting carbon/oxygen low-mass white dwarf models.

  18. A copper sulfate and hydroxylysine treatment regimen for enhancing collagen cross-linking and biomechanical properties in engineered neocartilage.

    PubMed

    Makris, Eleftherios A; MacBarb, Regina F; Responte, Donald J; Hu, Jerry C; Athanasiou, Kyriacos A

    2013-06-01

    The objective of this study was to improve the biomechanical properties of engineered neotissues through promoting the development of collagen cross-links. It was hypothesized that supplementing medium with copper sulfate and the amino acid hydroxylysine would enhance the activity of lysyl oxidase enzyme to form collagen cross-links, increasing the strength and integrity of the neotissue. Neocartilage constructs were generated using a scaffoldless, self-assembling process and treated with copper sulfate and hydroxylysine, either alone or in combination, following a 2-factor, full-factorial study design. Following a 6-wk culture period, the biomechanical and biochemical properties of the constructs were measured. Results found copper sulfate to significantly increase pyridinoline (PYR) cross-links in all copper sulfate-containing groups over controls. When copper sulfate and hydroxylysine were combined, the result was synergistic, with a 10-fold increase in PYR content over controls. This increase in PYR cross-links manifested in a 3.3-fold significant increase in the tensile properties of the copper sulfate + hydroxylysine group. In addition, an 123% increase over control values was detected in the copper sulfate group in terms of the aggregate modulus. These data elucidate the role of copper sulfate and hydroxylysine toward improving the biomechanical properties of neotissues through collagen cross-linking enhancement.

  19. Biological properties of coral GFP-type proteins provide clues for engineering novel optical probes and biosensors

    NASA Astrophysics Data System (ADS)

    Salih, Anya; Larkum, Anthony W.; Cronin, Thomas W.; Wiedenmann, Joerg; Szymczak, Ron; Cox, Guy C.

    2004-06-01

    In recent years, a variety of Green Fluorescent Protein (GFP)-like pigments have been discovered from corals and other marine organisms. They are widely used to expand the range of available GFP-type proteins in imaging applications, such as in vivo markers for gene expression and protein localization studies, FRET-based (Förster resonance energy transfer) multicolor imaging and biosensors. They have known diverse optical and biochemical properties but their in vivo spectral properties and biological function in marine organisms is only beginning to be understood. We have investigated their spectral diversity, optical properties and cellular microstructure in corals of the Great Barrier Reef with the aim of elucidating their photo-biological function/s as well as to identify novel proteins suitable for GFP-based technologies. We found numerous spectral variants, with emissions covering almost the full range of the visible spectrum. Many of these GFP-like proteins, especially in corals from the more extreme habitats, such as sun-exposed shallows or in deep water, showed a range of light-related spectral characteristics: high photostability, spectral tuning for energy transfer and dynamic photo-induced transformation properties. Intra-cellularly they were organized into spectral donor-acceptor pairs or even arrays, tuned for FRET. Coral color proteins thus offer an exciting potential to expand the use of the available GFPs in bio-imaging applications and as a basis for improved protein engineering.

  20. Combinatorial effect of substratum properties on mesenchymal stem cell sheet engineering and subsequent multi-lineage differentiation.

    PubMed

    Chuah, Yon Jin; Zhang, Ying; Wu, Yingnan; Menon, Nishanth V; Goh, Ghim Hian; Lee, Ann Charlene; Chan, Vincent; Zhang, Yilei; Kang, Yuejun

    2015-09-01

    Cell sheet engineering has been exploited as an alternative approach in tissue regeneration and the use of stem cells to generate cell sheets has further showed its potential in stem cell-mediated tissue regeneration. There exist vast interests in developing strategies to enhance the formation of stem cell sheets for downstream applications. It has been proved that stem cells are sensitive to the biophysical cues of the microenvironment. Therefore we hypothesized that the combinatorial substratum properties could be tailored to modulate the development of cell sheet formation and further influence its multipotency. For validation, polydimethylsiloxane (PDMS) of different combinatorial substratum properties (including stiffness, roughness and wettability) were created, on which the human bone marrow derived mesenchymal stem cells (BMSCs) were cultured to form cell sheets with their multipotency evaluated after induced differentiation. The results showed that different combinatorial effects of these substratum properties were able to influence BMSC behavior such as adhesion, spreading and proliferation during cell sheet development. Collagen formation within the cell sheet was enhanced on substrates with lower stiffness, higher hydrophobicity and roughness, which further assisted the induced chondrogenesis and osteogenesis, respectively. These findings suggested that combinatorial substratum properties had profound effects on BMSC cell sheet integrity and multipotency, which had significant implications for future biomaterials and scaffold designs in the field of BMSC-mediated tissue regeneration.

  1. KINEMATIC AND ENERGETIC PROPERTIES OF THE 2012 MARCH 12 POLAR CORONAL MASS EJECTION

    SciTech Connect

    Gopalswamy, N.; Yashiro, S.; Akiyama, S.

    2015-08-10

    We report on the energetics of the 2012 March 12 polar coronal mass ejection (CME) originating from a southern latitude of ∼60°. The polar CME is similar to low-latitude (LL) CMEs in almost all respects: three-part morphology; post-eruption arcade (PEA), CME, and filament kinematics; CME mass and kinetic energy; and the relative thermal energy content of the PEA. From polarized brightness images, we estimate the CME mass, which is close to the average mass of LL CMEs. The CME kinetic energy (3.3 × 10{sup 30} erg) is also typical of the general population of CMEs. From photospheric magnetograms, we estimate the free energy (1.8 × 10{sup 31} erg) in the polar crown source region, which we find is sufficient to power the CME and the PEA. About 19% of the free energy went into the CME kinetic energy. We compute the thermal energy content of the PEA (2.3 × 10{sup 29} erg) and find it to be a small fraction (6.8%) of the CME kinetic energy. This fraction is remarkably similar to that in active region CMEs associated with major flares. We also show that the 2012 March 12 is one among scores of polar CMEs observed during the maximum phase of cycle 24. The cycle 24 polar crown prominence eruptions have the same rate of association with CMEs as those from LLs. This investigation supports the view that all CMEs are magnetically propelled from closed field regions, irrespective of their location on the Sun (polar crown filament regions, quiescent filament regions, or active regions)

  2. Kinematic and Energetic Properties of the 2012 March 12 Polar Coronal Mass Ejection

    NASA Astrophysics Data System (ADS)

    Gopalswamy, N.; Yashiro, S.; Akiyama, S.

    2015-08-01

    We report on the energetics of the 2012 March 12 polar coronal mass ejection (CME) originating from a southern latitude of ∼60°. The polar CME is similar to low-latitude (LL) CMEs in almost all respects: three-part morphology; post-eruption arcade (PEA), CME, and filament kinematics; CME mass and kinetic energy; and the relative thermal energy content of the PEA. From polarized brightness images, we estimate the CME mass, which is close to the average mass of LL CMEs. The CME kinetic energy (3.3 × 1030 erg) is also typical of the general population of CMEs. From photospheric magnetograms, we estimate the free energy (1.8 × 1031 erg) in the polar crown source region, which we find is sufficient to power the CME and the PEA. About 19% of the free energy went into the CME kinetic energy. We compute the thermal energy content of the PEA (2.3 × 1029 erg) and find it to be a small fraction (6.8%) of the CME kinetic energy. This fraction is remarkably similar to that in active region CMEs associated with major flares. We also show that the 2012 March 12 is one among scores of polar CMEs observed during the maximum phase of cycle 24. The cycle 24 polar crown prominence eruptions have the same rate of association with CMEs as those from LLs. This investigation supports the view that all CMEs are magnetically propelled from closed field regions, irrespective of their location on the Sun (polar crown filament regions, quiescent filament regions, or active regions).

  3. Kinematic and Energetic Properties of the 2012 March 12 Polar Coronal Mass Ejection

    NASA Technical Reports Server (NTRS)

    Gopalswamy, N.; Yashiro, Seiji; Akiyama, S.

    2015-01-01

    We report on the energetics of the 2012 March 12 polar coronal mass ejection (CME) originating from a southern latitude of approximately 60deg. The polar CME is similar to low-latitude (LL) CMEs in almost all respects: three-part morphology; post-eruption arcade (PEA), CME, and filament kinematics; CME mass and kinetic energy; and the relative thermal energy content of the PEA. From polarized brightness images, we estimate the CME mass, which is close to the average mass of LL CMEs. The CME kinetic energy (3.3 × 10(sup 30) erg) is also typical of the general population of CMEs. From photospheric magnetograms, we estimate the free energy (1.8 × 10(sup 31) erg) in the polar crown source region, which we find is sufficient to power the CME and the PEA. About 19% of the free energy went into the CME kinetic energy. We compute the thermal energy content of the PEA (2.3 × 10(sup 29) erg) and find it to be a small fraction (6.8%) of the CME kinetic energy. This fraction is remarkably similar to that in active region CMEs associated with major flares. We also show that the 2012 March 12 is one among scores of polar CMEs observed during the maximum phase of cycle 24. The cycle 24 polar crown prominence eruptions have the same rate of association with CMEs as those from LLs. This investigation supports the view that all CMEs are magnetically propelled from closed field regions, irrespective of their location on the Sun (polar crown filament regions, quiescent filament regions, or active regions).

  4. Physical properties of bio-diesel & Implications for use of bio-diesel in diesel engines

    SciTech Connect

    Chakravarthy, Veerathu K; McFarlane, Joanna; Daw, C Stuart; Ra, Youngchul; Griffin, Jelani K

    2008-01-01

    In this study we identify components of a typical biodiesel fuel and estimate both their individual and mixed thermo-physical and transport properties. We then use the estimated mixture properties in computational simulations to gauge the extent to which combustion is modified when biodiesel is substituted for conventional diesel fuel. Our simulation studies included both regular diesel combustion (DI) and premixed charge compression ignition (PCCI). Preliminary results indicate that biodiesel ignition is significantly delayed due to slower liquid evaporation, with the effects being more pronounced for DI than PCCI. The lower vapor pressure and higher liquid heat capacity of biodiesel are two key contributors to this slower rate of evaporation. Other physical properties are more similar between the two fuels, and their impacts are not clearly evident in the present study. Future studies of diesel combustion sensitivity to both physical and chemical properties of biodiesel are suggested.

  5. Tensile and creep rupture properties of (16) uncoated and (2) coated engineering alloys at elevated temperatures

    NASA Technical Reports Server (NTRS)

    Fritz, L. J.; Koster, W. P.

    1977-01-01

    Sixteen test materials were supplied by NASA-Lewis Research Center as wrought bar or cast remelt stock. The cast remelt stock was cast into test blanks with two such materials being also evaluated after Jocoat coating was applied. Mechanical properties evaluated included tensile, modulus of elasticity, Poisson's Ratio, creep properties and creep rupture strength. Tests were conducted at temperatures applicable to the service temperature of the various alloys. This range extended from room temperature to 1000 C.

  6. Diffusion in random networks: Asymptotic properties, and numerical and engineering approximations

    NASA Astrophysics Data System (ADS)

    Padrino, Juan C.; Zhang, Duan Z.

    2016-11-01

    The ensemble phase averaging technique is applied to model mass transport by diffusion in random networks. The system consists of an ensemble of random networks, where each network is made of a set of pockets connected by tortuous channels. Inside a channel, we assume that fluid transport is governed by the one-dimensional diffusion equation. Mass balance leads to an integro-differential equation for the pores mass density. The so-called dual porosity model is found to be equivalent to the leading order approximation of the integration kernel when the diffusion time scale inside the channels is small compared to the macroscopic time scale. As a test problem, we consider the one-dimensional mass diffusion in a semi-infinite domain, whose solution is sought numerically. Because of the required time to establish the linear concentration profile inside a channel, for early times the similarity variable is xt- 1 / 4 rather than xt- 1 / 2 as in the traditional theory. This early time sub-diffusive similarity can be explained by random walk theory through the network. In addition, by applying concepts of fractional calculus, we show that, for small time, the governing equation reduces to a fractional diffusion equation with known solution. We recast this solution in terms of special functions easier to compute. Comparison of the numerical and exact solutions shows excellent agreement.

  7. A Kalman Filter for Mass Property and Thrust Identification of the Spin-Stabilized Magnetospheric Multiscale Formation

    NASA Technical Reports Server (NTRS)

    Queen, Steven Z.

    2015-01-01

    The Magnetospheric Multiscale (MMS) mission consists of four identically instrumented, spin-stabilized observatories, elliptically orbiting the Earth in a tetrahedron formation. For the operational success of the mission, on-board systems must be able to deliver high-precision orbital adjustment maneuvers. On MMS, this is accomplished using feedback from on-board star sensors in tandem with accelerometers whose measurements are dynamically corrected for errors associated with a spinning platform. In order to determine the required corrections to the measured acceleration, precise estimates of attitude, rate, and mass-properties are necessary. To this end, both an on-board and ground-based Multiplicative Extended Kalman Filter (MEKF) were formulated and implemented in order to estimate the dynamic and quasi-static properties of the spacecraft.

  8. On the shoulders of giants: properties of the stellar halo and the Milky Way mass distribution

    SciTech Connect

    Kafle, Prajwal Raj; Sharma, Sanjib; Lewis, Geraint F.; Bland-Hawthorn, Joss

    2014-10-10

    Halo stars orbit within the potential of the Milky Way, and hence their kinematics can be used to understand the underlying mass distribution. However, the inferred mass distribution depends sensitively on assumptions made on the density and the velocity anisotropy profiles of the tracer population. Also, there is a degeneracy between the parameters of the halo and those of the disk or bulge. Most previous attempts that use halo stars have made arbitrary assumptions about these. In this paper, we decompose the Galaxy into three major components—a bulge, a Miyamoto-Nagai disk, and a Navarro-Frenk-White dark matter halo - and then model the kinematic data of the halo blue horizontal branch and K-giant stars from the Sloan Extension for Galactic Understanding and Exploration. Additionally, we use the gas terminal velocity curve and the Sgr A* proper motion. With the distance of the Sun from the center of the Galaxy R {sub ☉} = 8.5 kpc, our kinematic analysis reveals that the density of the stellar halo has a break at 17.2{sub −1.0}{sup +1.1} kpc and an exponential cutoff in the outer parts starting at 97.7{sub −15.8}{sup +15.6} kpc. Also, we find that the tracer velocity anisotropy is radially biased with β {sub s} = 0.4 ± 0.2 in the outer halo. We measure halo virial mass M {sub vir} to be 0.80{sub −0.16}{sup +0.31}×10{sup 12} M{sub ⊙}, concentration c to be 21.1{sub −8.3}{sup +14.8}, disk mass to be 0.95{sub −0.30}{sup +0.24}×10{sup 11} M{sub ⊙}, disk scale length to be 4.9{sub −0.4}{sup +0.4} kpc, and bulge mass to be 0.91{sub −0.38}{sup +0.31}×10{sup 10} M{sub ⊙}. The halo mass is found to be small, and this has important consequences. The giant stars reveal that the outermost halo stars have low velocity dispersion, but interestingly this suggests a truncation of the stellar halo density rather than a small overall mass of the Galaxy. Our estimates of local escape velocity v{sub esc}=550.9{sub −22.1}{sup +32.4} km s{sup −1} and

  9. Quantitative analysis of fatty-acid-based biofuels produced by wild-type and genetically engineered cyanobacteria by gas chromatography-mass spectrometry.

    PubMed

    Guan, Wenna; Zhao, Hui; Lu, Xuefeng; Wang, Cong; Yang, Menglong; Bai, Fali

    2011-11-11

    Simple and rapid quantitative determination of fatty-acid-based biofuels is greatly important for the study of genetic engineering progress for biofuels production by microalgae. Ideal biofuels produced from biological systems should be chemically similar to petroleum, like fatty-acid-based molecules including free fatty acids, fatty acid methyl esters, fatty acid ethyl esters, fatty alcohols and fatty alkanes. This study founded a gas chromatography-mass spectrometry (GC-MS) method for simultaneous quantification of seven free fatty acids, nine fatty acid methyl esters, five fatty acid ethyl esters, five fatty alcohols and three fatty alkanes produced by wild-type Synechocystis PCC 6803 and its genetically engineered strain. Data obtained from GC-MS analyses were quantified using internal standard peak area comparisons. The linearity, limit of detection (LOD) and precision (RSD) of the method were evaluated. The results demonstrated that fatty-acid-based biofuels can be directly determined by GC-MS without derivation. Therefore, rapid and reliable quantitative analysis of fatty-acid-based biofuels produced by wild-type and genetically engineered cyanobacteria can be achieved using the GC-MS method founded in this work.

  10. HST/WFC3 OBSERVATIONS OF LOW-MASS GLOBULAR CLUSTERS AM 4 AND PALOMAR 13: PHYSICAL PROPERTIES AND IMPLICATIONS FOR MASS LOSS

    SciTech Connect

    Hamren, Katherine M.; Smith, Graeme H.; Guhathakurta, Puragra; Dolphin, Andrew E.; Weisz, Daniel R.; Rajan, Abhijith; Grillmair, Carl J.

    2013-11-01

    We investigate the loss of low-mass stars in two of the faintest globular clusters known, AM 4 and Palomar 13 (Pal 13), using HST/WFC3 F606W and F814W photometry. To determine the physical properties of each cluster—age, mass, metallicity, extinction, and present day mass function (MF)—we use the maximum likelihood color-magnitude diagram (CMD) fitting program MATCH and the Dartmouth, Padova, and BaSTI stellar evolution models. For AM 4, the Dartmouth models provide the best match to the CMD and yield an age of >13 Gyr, metallicity log Z/Z {sub ☉} = –1.68 ± 0.08, a distance modulus (m – M) {sub V} = 17.47 ± 0.03, and reddening A{sub V} = 0.19 ± 0.02. For Pal 13 the Dartmouth models give an age of 13.4 ± 0.5 Gyr, log Z/Z {sub ☉} = –1.55 ± 0.06, (m – M) {sub V} = 17.17 ± 0.02, and A{sub V} = 0.43 ± 0.01. We find that the systematic uncertainties due to choice in assumed stellar model greatly exceed the random uncertainties, highlighting the importance of using multiple stellar models when analyzing stellar populations. Assuming a single-sloped power-law MF, we find that AM 4 and Pal 13 have spectral indices α = +0.68 ± 0.34 and α = –1.67 ± 0.25 (where a Salpeter MF has α = +1.35), respectively. Comparing our derived slopes with literature measurements of cluster integrated magnitude (M{sub V} ) and MF slope indicates that AM 4 is an outlier. Its MF slope is substantially steeper than clusters of comparable luminosity, while Pal 13 has an MF in line with the general trend. We discuss both primordial and dynamical origins for the unusual MF slope of AM 4 and tentatively favor the dynamical scenario. However, MF slopes of more low luminosity clusters are needed to verify this hypothesis.

  11. Development Strategies for Herbal Products Reducing the Influence of Natural Variance in Dry Mass on Tableting Properties and Tablet Characteristics

    PubMed Central

    Qusaj, Ylber; Leng, Andreas; Alshihabi, Firas; Krasniqi, Blerim; Vandamme, Thierry

    2012-01-01

    One “Quality by Design” approach is the focus on the variability of the properties of the active substance. This is crucially important for active substances that are obtained from natural resources such as herbal plant material and extracts. In this paper, we present various strategies for the development of herbal products especially taking into account the natural batch-to-batch variability (mainly of the dry mass) of tablets that contain a fixed amount of tincture. The following steps in the development have been evaluated for the outcome of the physico-chemical properties of the resulting tablets and intermediates: concentration of the tincture extracted from Echinacea fresh plant, loading of the concentrate onto an inert carrier, the respective wet granulation and drying step, including milling, and the adjuvant excipients for the tablet compression step. The responses that were investigated are the mean particle size of the dried and milled granulates, compaction properties and disintegration time of the tablets. Increased particle size showed a significant increase of the disintegration time and a decrease of the compaction properties. In addition, our results showed that the particle size has a great dependency on the ratio of liquid to carrier during the wet granulation process. Thus, the variability of the respective parameters tested was influenced by the performed strategies, which is how the tincture correlated to its dry mass and the relation of the amount of carrier used. In order to optimize these parameters, a strategy considering the above-mentioned points has to be chosen. PMID:24300367

  12. Distribution of mesoscale elastic properties and mass density in the human femoral shaft.

    PubMed

    Rohrbach, Daniel; Grimal, Quentin; Varga, Peter; Peyrin, Francoise; Langer, Max; Laugier, Pascal; Raum, Kay

    2015-04-01

    Cortical bone properties are determined by tissue composition and structure at several hierarchical length scales. In this study, the spatial distribution of micro- and mesoscale elastic properties within a human femoral shaft has been investigated. Microscale tissue degree of mineralization (DMB), cortical vascular porosity Ct.Po and the average transverse isotropic stiffness tensor C(Micro) of cylindrical-shaped samples (diameter: 4.4 mm, N = 56) were obtained from cortical regions between 20 and 85% of the total femur length and around the periphery (anterior, medial, posterior and lateral quadrants) by means of synchrotron radiation µCT (SRµCT) and 50-MHz scanning acoustic microscopy (SAM). Within each cylinder, the volumetric bone mineral density (vBMD) and the mesoscale stiffness tensor C(Meso) were derived using a numerical homogenization approach. Moreover, microelastic maps of the axial elastic coefficient c33 measured by SAM at distinct cross-sectional locations along the femur were used to construct a 3-D multiscale elastic model of the femoral shaft. Variations of vBMD (6.1%) were much lower than the variations of mesoscale elastic coefficients (11.1-21.3%). The variation of DMB was only a minor predictor for variations of the mesoscale elastic properties (0.05 ≤ R(2) ≤ 0.34). Instead, variations of the mesoscale elastic properties could be explained by variations of cortical porosity and microscale elastic properties. These data were suitable inputs for numerical evaluations and may help to unravel the relations between structure and composition on the elastic function in cortical bone.

  13. Probing Structure Property Relationships in Complex Engineering Silicones by 1H NMR

    SciTech Connect

    Chinn, S C; Gjersing, E L; Maxwell, R S; Eastwood, E; Bowen, D; Stephens, T

    2006-07-14

    It is generally accepted that the properties of polymeric materials are controlled by the network structure and the reactions by which they have been constructed. These properties include the bulk moduli at creation, but also the properties as a function of age during use. In order to interpret mechanical properties and predict the time dependent changes in these properties, detailed knowledge of the effect of structural changes must be obtained. The degree and type of crosslinking, the molecular weight between crosslinks, the number of elastically ineffective chains (loops, dangling chain ends, sol-fraction) must be characterized. A number of theoretical and experimental efforts have been reported in the last few years on model networks prepared by endlinking reactions and the relationships of those structures with the ultimate mechanical properties. A range of experimental methods have been used to investigate structure including rheometric, scattering, infrared, {sup 29}Si MAS and CPMAS, {sup 1}H relaxation measurements, and recently {sup 1}H multiple quantum methods. Characterization of the growth of multiple quantum coherences have recently been shown to provide detailed insight into silicone network structure by the ability to selective probe the individual components of the polymer network, such as the polymer-filler interface or network chains. We have employed recently developed MQ methods to investigate the structure-property relationships in a series of complex, endlinked filled-PDMS blends. Here, a systematic study of the relationship between the molecular formulation, as dictated by the amount and type of crosslinks present and by the remaining network chains, and the segmental dynamics as observed by MQ NMR was performed.

  14. Physico-chemical properties and degradability of non-woven hyaluronan benzylic esters as tissue engineering scaffolds.

    PubMed

    Milella, E; Brescia, E; Massaro, C; Ramires, P A; Miglietta, M R; Fiori, V; Aversa, P

    2002-02-01

    The development of biocompatible materials which can be processed into three-dimensional scaffolds and the design of appropriate configurations in order to enable the cellular infiltration and proliferation is a major issue in the tissue engineering. The hyaluronan total benzyl ester (Hyaff 11) has been found to be suitable substrate to grow a variety of cell types. Since structural, physical, chemical and biological data can help for tailoring appropriate scaffold for tissue engineering, information on chemicophysical properties on degradability of hyaluronan total benzyl ester non-woven has been obtained. The thermal analysis, the evaluation of the surface chemical composition, the morphology, the mechanical behaviour and the swelling tests were carried out on these materials. The hyaluronan total benzyl ester non-woven showed a thermal stability up to 220 degrees C and the surface composition differed from that of the bulk for C-O and C-C contribution. No contaminant were detected. The non-woven swelled in culture medium. Moreover the mechanical tests showed that when submitted to a press treatment, the samples have best mechanical properties. The pressed Hyaff 11 non-woven undergoes degradation when exposed to DMEM. The frying and breaking of the fibres, a decrease of the mechanical properties and a molecular weight loss have been observed. First, the ester bond of the Hyaff 11 non-woven is hydrolysed and the benzylic alcohol is released and the low molecular weight values indicate that a cleavage of the polymer is promoted by the components of the culture medium. After 11 days, some fragments, constituted by hyaluronic acid with a molecular weight of 23,000 Da became soluble in the medium. No oligomer was detected.

  15. High Mesenchymal Stem Cell Seeding Densities in Hyaluronic Acid Hydrogels Produce Engineered Cartilage with Native Tissue Properties

    PubMed Central

    Erickson, Isaac E.; Kestle, Sydney R.; Zellars, Kilief H.; Farrell, Megan J.; Kim, Minwook; Burdick, Jason A.; Mauck, Robert L.

    2012-01-01

    Engineered cartilage based on adult mesenchymal stem cells (MSCs) is an alluring goal for the repair of articular defects. However, efforts to date have failed to generate constructs with sufficient mechanical properties to function in the demanding environment of the joint. Our findings with a novel photocrosslinked hyaluronic acid (HA) hydrogel suggest that stiff gels (high HA concentration, 5% w/vol) foster chondrogenic differentiation and matrix production, but limit overall functional maturation due to the inability of formed matrix to diffuse away from the point of production and form a contiguous network. In the current study, we hypothesized that increasing the MSC seeding density would decrease the required diffusional distance, and so expedite the development of functional properties. To test this hypothesis, bovine MSCs were encapsulated at seeding densities of either 20 or 60 million cells per mL in 1%, 3%, and 5% (w/vol) hyaluronic acid (HA) hydrogels. Counter our hypothesis, higher concentration HA gels (3% and 5%) did not develop more rapidly with increased MSC seeding density. However, the biomechanical properties of low concentration (1%) HA constructs increased markedly (nearly 3-fold with a 3-fold increase in seeding density). To ensure that optimal nutrient access was delivered, we next cultured these constructs under dynamic culture conditions (orbital shaking) for 9 weeks. Under these conditions, 1% HA seeded at 60 million MSCs per mL reached a compressive modulus in excess of 1 MPa (compared to 0.3-0.4MPa for free swelling constructs). This is the highest level we have reported to date in this HA hydrogel system, and represents a significant advance towards functional stem cell-based tissue engineered cartilage. PMID:22546516