Science.gov

Sample records for review engineering particles

  1. Review: engineering particles using the aerosol-through-plasma method

    SciTech Connect

    Phillips, Jonathan; Luhrs, Claudia C; Richard, Monique

    2009-01-01

    For decades, plasma processing of materials on the nanoscale has been an underlying enabling technology for many 'planar' technologies, particularly virtually every aspect of modern electronics from integrated-circuit fabrication with nanoscale elements to the newest generation of photovoltaics. However, it is only recent developments that suggest that plasma processing can be used to make 'particulate' structures of value in fields, including catalysis, drug delivery, imaging, higher energy density batteries, and other forms of energy storage. In this paper, the development of the science and technology of one class of plasma production of particulates, namely, aerosol-through-plasma (A-T-P), is reviewed. Various plasma systems, particularly RF and microwave, have been used to create nanoparticles of metals and ceramics, as well as supported metal catalysts. Gradually, the complexity of the nanoparticles, and concomitantly their potential value, has increased. First, unique two-layer particles were generated. These were postprocessed to create unique three-layer nanoscale particles. Also, the technique has been successfully employed to make other high-value materials, including carbon nanotubes, unsupported graphene, and spherical boron nitride. Some interesting plasma science has also emerged from efforts to characterize and map aerosol-containing plasmas. For example, it is clear that even a very low concentration of particles dramatically changes plasma characteristics. Some have also argued that the local-thermodynamic-equilibrium approach is inappropriate to these systems. Instead, it has been suggested that charged- and neutral-species models must be independently developed and allowed to 'interact' only in generation terms.

  2. Science and engineering of nanodiamond particle surfaces for biological applications (Review).

    PubMed

    Shenderova, Olga A; McGuire, Gary E

    2015-01-01

    Diamond has outstanding bulk properties such as super hardness, chemical inertness, biocompatibility, luminescence, to name just a few. In the nanoworld, in order to exploit these outstanding bulk properties, the surfaces of nanodiamond (ND) particles must be accordingly engineered for specific applications. Modification of functional groups on the ND's surface and the corresponding electrostatic properties determine their colloidal stability in solvents, formation of photonic crystals, controlled adsorption and release of cargo molecules, conjugation with biomolecules and polymers, and cellular uptake. The optical activity of the luminescent color centers in NDs depends on their proximity to the ND's surface and surface termination. In order to engineer the ND surface, a fundamental understanding of the specific structural features and sp(3)-sp(2) phase transformations on the surface of ND particles is required. In the case of ND particles produced by detonation of carbon containing explosives (detonation ND), it should also be taken into account that its structure depends on the synthesis parameters and subsequent processing. Thus, for development of a strategy of surface modification of detonation ND, it is imperative to know details of its production. In this review, the authors discuss ND particles structure, strategies for surface modification, electrokinetic properties of NDs in suspensions, and conclude with a brief overview of the relevant bioapplications. PMID:26245200

  3. Engineering Review Information System

    NASA Technical Reports Server (NTRS)

    Grems, III, Edward G. (Inventor); Henze, James E. (Inventor); Bixby, Jonathan A. (Inventor); Roberts, Mark (Inventor); Mann, Thomas (Inventor)

    2015-01-01

    A disciplinal engineering review computer information system and method by defining a database of disciplinal engineering review process entities for an enterprise engineering program, opening a computer supported engineering item based upon the defined disciplinal engineering review process entities, managing a review of the opened engineering item according to the defined disciplinal engineering review process entities, and closing the opened engineering item according to the opened engineering item review.

  4. Pharmaceutical Particle Engineering via Spray Drying

    PubMed Central

    2007-01-01

    This review covers recent developments in the area of particle engineering via spray drying. The last decade has seen a shift from empirical formulation efforts to an engineering approach based on a better understanding of particle formation in the spray drying process. Microparticles with nanoscale substructures can now be designed and their functionality has contributed significantly to stability and efficacy of the particulate dosage form. The review provides concepts and a theoretical framework for particle design calculations. It reviews experimental research into parameters that influence particle formation. A classification based on dimensionless numbers is presented that can be used to estimate how excipient properties in combination with process parameters influence the morphology of the engineered particles. A wide range of pharmaceutical application examples—low density particles, composite particles, microencapsulation, and glass stabilization—is discussed, with specific emphasis on the underlying particle formation mechanisms and design concepts. PMID:18040761

  5. Review of particle properties

    SciTech Connect

    Wohl; Cahn, R.N.; Rittenberg, A.; Trippe, T.G.; Yost, G.P.; Porter, F.; Hernandez, J.J.; Montanet, L.; Hendrick, R.E.; Crawford, R.L.

    1984-04-01

    This review of the properties of leptons, mesons, and baryons is an updating of the Review of Particle Properties, Particle Data Group (Phys. Lett. 111B (1982)). Data are evaluated, listed, averaged, and summarized in tables. Numerous tables, figures, and formulae of interest to particle physicists are also included. A data booklet is available.

  6. Classification of Volatile Engine Particles

    SciTech Connect

    Cheng, Mengdawn

    2013-01-01

    Volatile particles cannot be detected at the engine exhaust by an aerosol detector. They are formed when the exhaust is mixed with ambient air downstream. Lack of a precise definition of volatile engine particles has been an impediment to engine manufacturers and regulatory agencies involved in the development of an effective control strategy. It is beyond doubt that volatile particles from combustion sources contribute to the atmospheric particulate burden, and the effect of that contribution is a critical issue in the ongoing research in the areas of air quality and climate change. A new instrument, called volatile particle separator (VPS), has been developed. It utilizes a proprietary microporous metallic membrane to separate particles from vapors. VPS data were used in the development of a two-parameter function to quantitatively classify, for the first time, the volatilization behavior of engine particles. The value of parameter A describes the volatilization potential of an aerosol. A nonvolatile particle has a larger A-value than a volatile one. The value of parameter k, an effective evaporation energy barrier, is found to be much smaller for small engine particles than that for large engine particles. The VPS instrument provides a means beyond just being a volatile particle remover; it enables a numerical definition to characterize volatile engine particles.

  7. Review of Particle Physics

    NASA Astrophysics Data System (ADS)

    Olive, K. A.; Particle Data Group

    2014-08-01

    The Review summarizes much of particle physics and cosmology. Using data from previous editions, plus 3,283 new measurements from 899 papers, we list, evaluate, and average measured properties of gauge bosons and the recently discovered Higgs boson, leptons, quarks, mesons, and baryons. We summarize searches for hypothetical particles such as heavy neutrinos, supersymmetric and technicolor particles, axions, dark photons, etc. All the particle properties and search limits are listed in Summary Tables. We also give numerous tables, figures, formulae, and reviews of topics such as Supersymmetry, Extra Dimensions, Particle Detectors, Probability, and Statistics. Among the 112 reviews are many that are new or heavily revised including those on: Dark Energy, Higgs Boson Physics, Electroweak Model, Neutrino Cross Section Measurements, Monte Carlo Neutrino Generators, Top Quark, Dark Matter, Dynamical Electroweak Symmetry Breaking, Accelerator Physics of Colliders, High-Energy Collider Parameters, Big Bang Nucleosynthesis, Astrophysical Constants and Cosmological Parameters. All tables, listings, and reviews (and errata) are also available on the Particle Data Group website: http://pdg.lbl.gov. Contents Abstract, Contributors, Highlights and Table of ContentsAcrobat PDF (4.4 MB) IntroductionAcrobat PDF (595 KB) Particle Physics Summary Tables Gauge and Higgs bosonsAcrobat PDF (204 KB) LeptonsAcrobat PDF (167 KB) QuarksAcrobat PDF (115 KB) MesonsAcrobat PDF (976 KB) BaryonsAcrobat PDF (384 KB) Searches (Supersymmetry, Compositeness, etc.)Acrobat PDF (120 KB) Tests of conservation lawsAcrobat PDF (383 KB) Reviews, Tables, and Plots Detailed contents for this sectionAcrobat PDF (73 KB) Constants, Units, Atomic and Nuclear PropertiesAcrobat PDF (395 KB) Standard Model and Related TopicsAcrobat PDF (8.37 MB) Astrophysics and CosmologyAcrobat PDF (3.79 MB) Experimental Methods and CollidersAcrobat PDF (3.82 MB) Mathematical Tools of Statistics, Monte Carlo, Group Theory Acrobat

  8. NSI engineering review

    NASA Technical Reports Server (NTRS)

    Leon, Mark

    1991-01-01

    An engineering review is given of NASA Science Internet (NSI). An outline of the review is presented along with a list of new connections. A map is illustrated of NSI installations. And a listing is given of upgrade scheduling for 1991, 1992, and 1993.

  9. Particle Bed Reactor engine technology

    SciTech Connect

    Sandler, S.; Feddersen, R. )

    1992-01-01

    This paper discusses the Particle Bed Reactor (PBR) based propulsion system being developed under the Space Nuclear Thermal Propulsion (SNTP) program. A PBR engine is a light weight, compact propulsion system which offers significant improvement over current technology systems. Current performance goals are a system thrust of 75,000 pounds at an Isp of 1000 sec. A target thrust to weight ratio (T/W) of 30 has been established for an unshielded engine. The functionality of the PBR, its pertinent technology issues and the systems required to make up a propulsion system are described herein. Accomplishments to date which include hardware development and tests for the PBR engine are also discussed. This paper is intended to provide information on and describe the current state-of-the-art of PBR technology. 4 refs.

  10. Mechanical Engineering Department technical review

    SciTech Connect

    Carr, R.B.; Abrahamson, L.; Denney, R.M.; Dubois, B.E

    1982-01-01

    Technical achievements and publication abstracts related to research in the following Divisions of Lawrence Livermore Laboratory are reported in this biannual review: Nuclear Fuel Engineering; Nuclear Explosives Engineering; Weapons Engineering; Energy Systems Engineering; Engineering Sciences; Magnetic Fusion Engineering; and Material Fabrication. (LCL)

  11. Engineering Technical Review Planning Briefing

    NASA Technical Reports Server (NTRS)

    Gardner, Terrie

    2012-01-01

    The general topics covered in the engineering technical planning briefing are 1) overviews of NASA, Marshall Space Flight Center (MSFC), and Engineering, 2) the NASA Systems Engineering(SE) Engine and its implementation , 3) the NASA Project Life Cycle, 4) MSFC Technical Management Branch Services in relation to the SE Engine and the Project Life Cycle , 5) Technical Reviews, 6) NASA Human Factor Design Guidance , and 7) the MSFC Human Factors Team. The engineering technical review portion of the presentation is the primary focus of the overall presentation and will address the definition of a design review, execution guidance, the essential stages of a technical review, and the overall review planning life cycle. Examples of a technical review plan content, review approaches, review schedules, and the review process will be provided and discussed. The human factors portion of the presentation will focus on the NASA guidance for human factors. Human factors definition, categories, design guidance, and human factor specialist roles will be addressed. In addition, the NASA Systems Engineering Engine description, definition, and application will be reviewed as background leading into the NASA Project Life Cycle Overview and technical review planning discussion.

  12. Review of jet engine emissions

    NASA Technical Reports Server (NTRS)

    Grobman, J. S.

    1972-01-01

    A review of the emission characteristics of jet engines is presented. The sources and concentrations of the various constituents in the engine exhaust and the influence of engine operating conditions on emissions are discussed. Cruise emissions to be expected from supersonic engines are compared with emissions from subsonic engines. The basic operating principles of the gas turbine combustor are reviewed together with the effects of combustor operating conditions on emissions. The performance criteria that determine the design of gas turbine combustors are discussed. Combustor design techniques are considered that may be used to reduce emissions.

  13. Apparatus for separating particles utilizing engineered acoustic contrast capture particles

    SciTech Connect

    Kaduchak, Gregory; Ward, Michael D

    2014-10-21

    An apparatus for separating particles from a medium includes a capillary defining a flow path therein that is in fluid communication with a medium source. The medium source includes engineered acoustic contrast capture particle having a predetermined acoustic contrast. The apparatus includes a vibration generator that is operable to produce at least one acoustic field within the flow path. The acoustic field produces a force potential minima for positive acoustic contrast particles and a force potential minima for negative acoustic contrast particles in the flow path and drives the engineered acoustic contrast capture particles to either the force potential minima for positive acoustic contrast particles or the force potential minima for negative acoustic contrast particles.

  14. Apparatus for separating particles utilizing engineered acoustic contrast capture particles

    DOEpatents

    Kaduchak, Gregory; Ward, Michael D.

    2011-12-27

    An apparatus for separating particles from a medium includes a capillary defining a flow path therein that is in fluid communication with a medium source. The medium source includes engineered acoustic contrast capture particle having a predetermined acoustic contrast. The apparatus includes a vibration generator that is operable to produce at least one acoustic field within the flow path. The acoustic field produces a force potential minima for positive acoustic contrast particles and a force potential minima for negative acoustic contrast particles in the flow path and drives the engineered acoustic contrast capture particles to either the force potential minima for positive acoustic contrast particles or the force potential minima for negative acoustic contrast particles.

  15. Apparatus for separating particles utilizing engineered acoustic contrast capture particles

    DOEpatents

    Kaduchak, Gregory; Ward, Michael D

    2016-05-17

    An apparatus for separating particles from a medium includes a capillary defining a flow path therein that is in fluid communication with a medium source. The medium source includes engineered acoustic contrast capture particle having a predetermined acoustic contrast. The apparatus includes a vibration generator that is operable to produce at least one acoustic field within the flow path. The acoustic field produces a force potential minima for positive acoustic contrast particles and a force potential minima for negative acoustic contrast particles in the flow path and drives the engineered acoustic contrast capture particles to either the force potential minima for positive acoustic contrast particles or the force potential minima for negative acoustic contrast particles.

  16. Gas turbine engines with particle traps

    DOEpatents

    Boyd, Gary L.; Sumner, D. Warren; Sheoran, Yogendra; Judd, Z. Daniel

    1992-01-01

    A gas turbine engine (10) incorporates a particle trap (46) that forms an entrapment region (73) in a plenum (24) which extends from within the combustor (18) to the inlet (32) of a radial-inflow turbine (52, 54). The engine (10) is thereby adapted to entrap particles that originate downstream from the compressor (14) and are otherwise propelled by combustion gas (22) into the turbine (52, 54). Carbonaceous particles that are dislodged from the inner wall (50) of the combustor (18) are incinerated within the entrapment region (73) during operation of the engine (10).

  17. Mechanical Engineering Department Technical Review

    SciTech Connect

    Carr, R.B.; Denney, R.M.

    1981-07-01

    The Mechanical Engineering Department Technical Review is published to inform readers of various technical activities within the Department, promote exchange of ideas, and give credit to personnel who are achieving the results. The report is presented in two parts: technical achievements and publication abstracts. The first is divided into seven sections, each of which reports on an engineering division and its specific activities related to nuclear tests, nuclear explosives, weapons, energy systems, engineering sciences, magnetic fusion, and materials fabrication.

  18. Engineered plant biomass feedstock particles

    DOEpatents

    Dooley, James H.; Lanning, David N.; Broderick, Thomas F.

    2011-10-18

    A novel class of flowable biomass feedstock particles with unusually large surface areas that can be manufactured in remarkably uniform sizes using low-energy comminution techniques. The feedstock particles are roughly parallelepiped in shape and characterized by a length dimension (L) aligned substantially with the grain direction and defining a substantially uniform distance along the grain, a width dimension (W) normal to L and aligned cross grain, and a height dimension (H) normal to W and L. The particles exhibit a disrupted grain structure with prominent end and surface checks that greatly enhances their skeletal surface area as compared to their envelope surface area. The L.times.H dimensions define a pair of substantially parallel side surfaces characterized by substantially intact longitudinally arrayed fibers. The W.times.H dimensions define a pair of substantially parallel end surfaces characterized by crosscut fibers and end checking between fibers. The L.times.W dimensions define a pair of substantially parallel top surfaces characterized by some surface checking between longitudinally arrayed fibers. At least 80% of the particles pass through a 1/4 inch screen having a 6.3 mm nominal sieve opening but are retained by a No. 10 screen having a 2 mm nominal sieve opening. The feedstock particles are manufactured from a variety of plant biomass materials including wood, crop residues, plantation grasses, hemp, bagasse, and bamboo.

  19. Engineered plant biomass feedstock particles

    DOEpatents

    Dooley, James H.; Lanning, David N.; Broderick, Thomas F.

    2011-10-11

    A novel class of flowable biomass feedstock particles with unusually large surface areas that can be manufactured in remarkably uniform sizes using low-energy comminution techniques. The feedstock particles are roughly parallelepiped in shape and characterized by a length dimension (L) aligned substantially with the grain direction and defining a substantially uniform distance along the grain, a width dimension (W) normal to L and aligned cross grain, and a height dimension (H) normal to W and L. The particles exhibit a disrupted grain structure with prominent end and surface checks that greatly enhances their skeletal surface area as compared to their envelope surface area. The L.times.H dimensions define a pair of substantially parallel side surfaces characterized by substantially intact longitudinally arrayed fibers. The W.times.H dimensions define a pair of substantially parallel end surfaces characterized by crosscut fibers and end checking between fibers. The L.times.W dimensions define a pair of substantially parallel top surfaces characterized by some surface checking between longitudinally arrayed fibers. The feedstock particles are manufactured from a variety of plant biomass materials including wood, crop residues, plantation grasses, hemp, bagasse, and bamboo.

  20. Engineered plant biomass feedstock particles

    DOEpatents

    Dooley, James H.; Lanning, David N.; Broderick, Thomas F.

    2012-04-17

    A new class of plant biomass feedstock particles characterized by consistent piece size and shape uniformity, high skeletal surface area, and good flow properties. The particles of plant biomass material having fibers aligned in a grain are characterized by a length dimension (L) aligned substantially parallel to the grain and defining a substantially uniform distance along the grain, a width dimension (W) normal to L and aligned cross grain, and a height dimension (H) normal to W and L. In particular, the L.times.H dimensions define a pair of substantially parallel side surfaces characterized by substantially intact longitudinally arrayed fibers, the W.times.H dimensions define a pair of substantially parallel end surfaces characterized by crosscut fibers and end checking between fibers, and the L.times.W dimensions define a pair of substantially parallel top and bottom surfaces. The L.times.W surfaces of particles with L/H dimension ratios of 4:1 or less are further elaborated by surface checking between longitudinally arrayed fibers. The length dimension L is preferably aligned within 30.degree. parallel to the grain, and more preferably within 10.degree. parallel to the grain. The plant biomass material is preferably selected from among wood, agricultural crop residues, plantation grasses, hemp, bagasse, and bamboo.

  1. Potential Climate Impacts of Engine Particle Emissions

    NASA Technical Reports Server (NTRS)

    Kawa, S. Randy

    1999-01-01

    Solid (soot) and liquid (presumed sulfate) particle emissions from aircraft engines may have serious impacts on the atmosphere. While the direct radiative impact of these particles is expected to be small relative to those from natural sources (Atmospheric Effects of Subsonic Aircraft: Interim Assessment of the Advanced Subsonic Technology Program, NASA Ref. Pub. 1400, 1997), their indirect effects on atmospheric chemistry and cloud formation may have a significant impact. The potential impacts of primary concern are the increase of sulfate surface area and accelerated heterogeneous chemical reactions, and the potential for either modified soot or sulfate particles to serve as cloud nuclei which would change the frequency or radiative characteristics of clouds. Volatile (sulfate) particle concentrations measured behind the Concorde aircraft in flight in the stratosphere were much higher than expected from near-field model calculations of particle formation and growth. Global model calculations constrained by these data calculate a greater level of stratospheric ozone depletion from the proposed High speed Civil Transport (HSCT) fleet than those without particle emission. Soot particles have also been proposed as important in heterogeneous chemistry but this remains to be substantiated. Aircraft volatile particle production in the troposphere has been shown by measurements to depend strongly on fuel sulfur content. Sulfate particles of sufficient size are known to provide a good nucleating surface for cloud growth. Although pure carbon soot is hydrophobic, the solid particle surface may incorporate more suitable nucleating sites. The non-volatile (soot) particles also tend to occupy the large end of aircraft particle size spectra. Quantitative connection between aircraft particle emissions and cloud modification has not been established yet, however, even small changes in cloud amount or properties could have a significant effect on the radiative balance of the

  2. Single-particle stochastic heat engine.

    PubMed

    Rana, Shubhashis; Pal, P S; Saha, Arnab; Jayannavar, A M

    2014-10-01

    We have performed an extensive analysis of a single-particle stochastic heat engine constructed by manipulating a Brownian particle in a time-dependent harmonic potential. The cycle consists of two isothermal steps at different temperatures and two adiabatic steps similar to that of a Carnot engine. The engine shows qualitative differences in inertial and overdamped regimes. All the thermodynamic quantities, including efficiency, exhibit strong fluctuations in a time periodic steady state. The fluctuations of stochastic efficiency dominate over the mean values even in the quasistatic regime. Interestingly, our system acts as an engine provided the temperature difference between the two reservoirs is greater than a finite critical value which in turn depends on the cycle time and other system parameters. This is supported by our analytical results carried out in the quasistatic regime. Our system works more reliably as an engine for large cycle times. By studying various model systems, we observe that the operational characteristics are model dependent. Our results clearly rule out any universal relation between efficiency at maximum power and temperature of the baths. We have also verified fluctuation relations for heat engines in time periodic steady state. PMID:25375477

  3. Mechanical Engineering Department. Technical review

    SciTech Connect

    Simecka, W.B.; Condouris, R.A.; Talaber, C.

    1980-01-01

    The Mechanical Engineering Department Technical Review is published to (1) inform the readers of various technical activities within the Department, (2) promote exchange of ideas, and (3) give credit to the personnel who are achieving the results. The report is formatted into two parts: technical achievements and publication abstracts. The first is divided into eight sections, one for each Division in the Department providing the reader with the names of the personnel and the Division accomplishing the work.

  4. Mechanical engineering department technical review

    SciTech Connect

    Carr, R.B. Denney, R.M.

    1981-01-01

    The Mechanical Engineering Department Technical Review is published to: (1) inform the readers of various technical activities within the department, (2) promote exchange of ideas, and (3) give credit to the personnel who are achieving the results. The report is formatted into two parts: technical acievements and publication abstracts. The first is divided into eight sections, one for each division in the department providing the reader with the names of the personnel and the division accomplishing the work.

  5. Efficiency of single-particle engines

    NASA Astrophysics Data System (ADS)

    Proesmans, Karel; Driesen, Cedric; Cleuren, Bart; Van den Broeck, Christian

    2015-09-01

    We study the efficiency of a single-particle Szilard and Carnot engine. Within a first order correction to the quasistatic limit, the work distribution is found to be Gaussian and the correction factor to average work and efficiency only depends on the piston speed. The stochastic efficiency is studied for both models and the recent findings on efficiency fluctuations are confirmed numerically. Special features are revealed in the zero-temperature limit.

  6. Efficiency of single-particle engines.

    PubMed

    Proesmans, Karel; Driesen, Cedric; Cleuren, Bart; Van den Broeck, Christian

    2015-09-01

    We study the efficiency of a single-particle Szilard and Carnot engine. Within a first order correction to the quasistatic limit, the work distribution is found to be Gaussian and the correction factor to average work and efficiency only depends on the piston speed. The stochastic efficiency is studied for both models and the recent findings on efficiency fluctuations are confirmed numerically. Special features are revealed in the zero-temperature limit. PMID:26465424

  7. Controlled manipulation of engineered colloidal particles

    NASA Astrophysics Data System (ADS)

    Nunes, Janine

    This research utilized the Particle Replication in Non-wetting Templates (PRINTRTM) technology to fabricate highly tailored colloidal particles. The behavior of these engineered particles were studied as they were subjected to different precisely controlled external influences, including electric fields, magnetic fields and a templating approach based on the PRINT process. Given the tunability in particle properties afforded by the PRINT process, exceptional control of the resulting particle assemblies and particle mobility were observed, suggesting potential applications in numerous materials and life science applications that require control on the nanoscale. As the PRINT process was integral to all aspects of this research, it was important to gain a clear understanding of mechanism by which perfluoropolyether (PFPE) elastomeric molds can generate monodisperse arrays of discrete, uniform particles with tailored size, shape and composition. Thus, fundamental studies were conducted on the PFPE elastomers, focusing on contact mechanics measurements and capillary flow experiments. The results confirmed the low surface energy of PFPE, an important property that renders the PFPE molds ideal for the PRINT process. Capillary flow experiments were conducted to study the method by which PFPE molds can be filled during the PRINT process. The flow in closed PFPE microchannels was compared to that in PDMS and glass. Suspensions of PRINT particles were studied in the presence of electric and magnetic fields. Electric field experiments were conducted using non-uniform alternating current electric fields and uniform direct current electric fields. Magnetic field experiments were conducted using both stationary and rotating magnetic fields. Particle assemblies were observed to form and could be tuned by particle shape and composition. Particle motion, both translational and rotational, was also controlled. Properties were found to be both shape and composition dependent. These

  8. Exhaust particle removing system for an engine

    SciTech Connect

    Shinzawa, M.

    1986-12-23

    A method is described comprising the steps of: (a) measuring degree of clogging of a filter which traps particles suspended in exhaust gas emitted from an engine; (b) indicating when the measured degree of clogging of the filter is equal to or greater than a first reference level; (c) burning off the particles deposited on the filter when the measured degree of clogging of the filter is equal to or greater than the first reference level and when a manual switch is in a preset position; and (d) burning off the particles deposited on the filter independent of whether or not the manual switch is in the preset position when the measured degree of clogging of the filter is equal to or greater than a second reference level greater than the first reference level.

  9. Holographic Particle Image Velocimetry and its Application in Engine Development

    NASA Astrophysics Data System (ADS)

    Coupland, J. M.; Garner, C. P.; Alcock, R. D.; Halliwell, N. A.

    2006-07-01

    This paper reviews Holographic Particle Image Velocimetry (HPIV) as a means to make three-component velocity measurements throughout a three-dimensional flow-field of interest. A simplified treatment of three-dimensional scalar wave propagation is outlined and subsequently used to illustrate the principles of complex correlation analysis. It is shown that this type of analysis provides the three-dimensional correlation of the propagating, monochromatic fields recorded by the hologram. A similar approach is used to analyse the Object Conjugate Reconstruction (OCR) technique to resolve directional ambiguity by introducing an artificial image shift to the reconstructed particle images. An example of how these methods are used together to measure the instantaneous flow fields within a motored Diesel engine is then described.

  10. Particle engineering in pharmaceutical solids processing: surface energy considerations.

    PubMed

    Williams, Daryl R

    2015-01-01

    During the past 10 years particle engineering in the pharmaceutical industry has become a topic of increasing importance. Engineers and pharmacists need to understand and control a range of key unit manufacturing operations such as milling, granulation, crystallisation, powder mixing and dry powder inhaled drugs which can be very challenging. It has now become very clear that in many of these particle processing operations, the surface energy of the starting, intermediate or final products is a key factor in understanding the processing operation and or the final product performance. This review will consider the surface energy and surface energy heterogeneity of crystalline solids, methods for the measurement of surface energy, effects of milling on powder surface energy, adhesion and cohesion on powder mixtures, crystal habits and surface energy, surface energy and powder granulation processes, performance of DPI systems and finally crystallisation conditions and surface energy. This review will conclude that the importance of surface energy as a significant factor in understanding the performance of many particulate pharmaceutical products and processes has now been clearly established. It is still nevertheless, work in progress both in terms of development of methods and establishing the limits for when surface energy is the key variable of relevance. PMID:25876912

  11. Conformal Electromagnetic Particle in Cell: A Review

    SciTech Connect

    Meierbachtol, Collin S.; Greenwood, Andrew D.; Verboncoeur, John P.; Shanker, Balasubramaniam

    2015-10-26

    We review conformal (or body-fitted) electromagnetic particle-in-cell (EM-PIC) numerical solution schemes. Included is a chronological history of relevant particle physics algorithms often employed in these conformal simulations. We also provide brief mathematical descriptions of particle-tracking algorithms and current weighting schemes, along with a brief summary of major time-dependent electromagnetic solution methods. Several research areas are also highlighted for recommended future development of new conformal EM-PIC methods.

  12. A review of particle resuspension

    NASA Astrophysics Data System (ADS)

    Nicholson, K. W.

    Some of the various types of studies on particle resuspension or re-entrainment are summarized along with shortcomings. General experimental aspects have been considered, rather than focusing on the numerical values of results, and research on erosion and resuspension by mechanisms other than wind has been included. It is evident that experiments have been performed in a wide range of environmental conditions but that additional research is required, in many areas, if a quantitative assessment of resuspension is to be achieved.

  13. RS-84 Engine Completes Design Review

    NASA Technical Reports Server (NTRS)

    2003-01-01

    This is an artist's concept of the kerosene-fueled RS-84 engine, one of several technologies competing to power NASA's next generation of launch vehicles. The RS-84 has successfully completed its preliminary design review as a reusable, liquid kerosene booster engine that will deliver a thrust level of 1 million pounds of force. The preliminary design review is a lengthy technical analysis that evaluates engine design according to stringent system requirements. The review ensures development is on target to meet Next Generation Launch Technology goals: Improved safety, reliability, and cost.

  14. Value-Engineering Review for Numerical Control

    NASA Technical Reports Server (NTRS)

    Warner, J. L.

    1984-01-01

    Selecting parts for conversion from conventional machining to numerical control, value-engineering review performed for every part to identify potential changes to part design that result in increased production efficiency.

  15. Particle filter-based prognostics: Review, discussion and perspectives

    NASA Astrophysics Data System (ADS)

    Jouin, Marine; Gouriveau, Rafael; Hissel, Daniel; Péra, Marie-Cécile; Zerhouni, Noureddine

    2016-05-01

    Particle filters are of great concern in a large variety of engineering fields such as robotics, statistics or automatics. Recently, it has developed among Prognostics and Health Management (PHM) applications for diagnostics and prognostics. According to some authors, it has ever become a state-of-the-art technique for prognostics. Nowadays, around 50 papers dealing with prognostics based on particle filters can be found in the literature. However, no comprehensive review has been proposed on the subject until now. This paper aims at analyzing the way particle filters are used in that context. The development of the tool in the prognostics' field is discussed before entering the details of its practical use and implementation. Current issues are identified, analyzed and some solutions or work trails are proposed. All this aims at highlighting future perspectives as well as helping new users to start with particle filters in the goal of prognostics.

  16. Electronics Engineering Department EE technical review

    SciTech Connect

    Not Available

    1984-04-01

    This is a technical review of work done by the Electronics Engineering Department of the Lawrence Livermore National Laboratory. Titles of papers included in this review are as follows: Motion-Control System for the Large Optics Diamond Turning Machine; A New Rotating Turbine Camera Controller that Extends Capability and Improves Reliability; The Ring Seating System and The LGF Data Acquisition System.

  17. BOOK REVIEW: ENVIRONMENTAL ENGINEERING, 5TH EDITION

    EPA Science Inventory

    Book Review of Environmental Engineering, 5th Edition (Joseph A. Salvato, Nelson L. Nemerow, Franklin J. Agardy (Editors), John Wiley and Sons, Inc. Hoboken, New Jersey. 2003.). Author wrote review per the request of the Editor-in-Chief of the Journal of Environmental Quality.

  18. Exhaust particle removing system for an internal combustion engine

    SciTech Connect

    Shinzawa, M.

    1988-07-12

    An exhaust particle removing system is described for an engine, comprising: (a) a filter for trapping particles in exhaust from the engine; (b) means for determining whether or not the degree of clogging of the filter is unacceptable; (c) means for detecting an operating condition of the engine; (d) means for when the degree of clogging of the filter is unacceptable, throttling the flow of intake air into the engine and thus varying the pressure of the intake air in accordance with the detected engine operating condition in cases where the detected engine operating condition resides in a first predetermined range within which the temperature of the engine exhaust would be inadequate to burn off the trapped particles if the intake air flow were not throttled, the throttling means comprising a movable throttle valve disposed in an air intake passage, a bypass passage connected to the air intake passage and bypassing the throttle valve, and a movable bypass valve disposed in the bypass passage; and (e) means for, when the degree of clogging of the filter is unacceptable, allowing free flow of the intake air in cases where the detected engine operating condition resides in a second predetermined range within which the temperature of the engine exhaust would be adequate to burn off the trapped particles even if the intake air flow were not throttled.

  19. Nuclear rocket engine design based on the particle bed reactor

    SciTech Connect

    Powell, J.R.; Ludewig, H.; Mughabghab, S.; Lazareth, O. Jr.; Schmidt, E.; Maise, G. )

    1993-01-01

    A nuclear thermal rocket (NTR) engine design based on the particle-bed reactor (PBR) concept is described in this paper. This engine is designed to satisfy a mission to Mars and thus must develop a thrust of [approximately]1.75 (6) N. This requirement is satisfied if the reactor generates 2000 MW of power.

  20. Hydropower engineering handbook: A review

    SciTech Connect

    Burgoine, D.

    1991-04-01

    This article is a review of a handbook developed out of a four-day course on hydropower development presented by the books editors. The book is designed to provide a short explanation of a particular phenomenon, some design and operational guidelines, and references to other more specific publications. The book also addresses environment impacts of hydropower facilities.

  1. Engineering particle morphology with microfluidic droplets

    NASA Astrophysics Data System (ADS)

    Kang, Zhanxiao; Kong, Tiantian; Lei, Leyan; Zhu, Pingan; Tian, Xiaowei; Wang, Liqiu

    2016-07-01

    The controlled generation of microparticles with non-spherical features is of increasing importance. Such particles are useful for fundamental studies in areas such as self-assembly, as well as biomedical applications from drug carriers to photonic devices. We propose a simple model that captures the dominating factors controlling the size and morphology of non-spherical particles from phase separated droplets. The validity of our model is verified by comparing the generated non-spherical microparticles by droplet microfluidics. This simple relationship between the dominating factors and the final morphologies enables the production of non-spherical particles with well-defined shapes and tightly-controlled dimensions for a variety of applications from drug delivery vehicles to structural materials.

  2. Spouting of biomass particles: a review.

    PubMed

    Cui, Heping; Grace, John R

    2008-07-01

    Recent research on biomass multiphase flow in spouted beds is reviewed, beginning with fundamental work on hydrodynamic parameters, such as minimum spouting velocity, pressure drop and fountain height. We then consider experimental studies on biomass multiphase flow in such processes as pulp drying, liquid spouting of pulp fibres, drying and coating of agricultural biomass, and bioreactors. Finally, we summarize modelling efforts with respect to spouting of biomass particles. PMID:17570657

  3. Review of progress in magnetic particle inspection

    NASA Astrophysics Data System (ADS)

    Eisenmann, David J.; Enyart, Darrel; Lo, Chester; Brasche, Lisa

    2014-02-01

    Magnetic particle inspection (MPI) has been widely utilized for decades, and sees considerable use in the aerospace industry with a majority of the steel parts being inspected with MPI at some point in the lifecycle. Typical aircraft locations inspected are landing gear, engine components, attachment hardware, and doors. In spite of its numerous applications the method remains poorly understood, and there are many aspects of that method which would benefit from in-depth study. This shortcoming is due to the fact that MPI combines the complicated nature of electromagnetics, metallurgical material effects, fluid-particle motion dynamics, and physiological human factors into a single inspection. To promote understanding of the intricate method issues that affect sensitivity, or to assist with the revision of industry specifications and standards, research studies will be prioritized through the guidance of a panel of industry experts, using an approach which has worked successfully in the past to guide fluorescent penetrant inspection (FPI) research efforts.

  4. AN ENGINE EXHAUST PARTICLE SIZERTM SPECTROMETER FOR TRANSIENT EMISSION PARTICLE MEASUREMENTS

    SciTech Connect

    Johnson, T; Caldow, R; Pucher, A; Mirme, A; Kittelson, D

    2003-08-24

    There has been increased interest in obtaining size distribution data during transient engine operation where both particle size and total number concentrations can change dramatically. Traditionally, the measurement of particle emissions from vehicles has been a compromise based on choosing between the conflicting needs of high time resolution or high particle size resolution for a particular measurement. Currently the most common technique for measuring submicrometer particle sizes is the Scanning Mobility Particle Sizer (SMPSTM) system. The SMPS system gives high size resolution but requires an aerosol to be stable over a long time period to make a particle size distribution measurement. A Condensation Particle Counter (CPC) is commonly used for fast time response measurements but is limited to measuring total concentration only. This paper describes a new instrument, the Engine Exhaust Particle SizerTM (EEPSTM) spectrometer, which has high time resolution and a reasonable size resolution. The EEPS was designed specifically for measuring engine exhaust and, like the SMPS system, uses a measurement based on electrical mobility. Particles entering the instrument are charged to a predictable level, then passed through an annular space where they are repelled outward by the voltage from a central column. When the particles reach electrodes on the outer cylindrical (a column of rings), they create a current that is measured by an electrometer on one or more of the rings. The electrometer currents are measured multiple times per second to give high time resolution. A sophisticated realtime inversion algorithm converts the currents to particle size and concentration for immediate display.

  5. AN ENGINE EXHAUST PARTICLE SIZER{trademark} SPECTROMETER FOR TRANSIENT EMISSION PARTICLE MEASUREMENTS

    SciTech Connect

    Johnson, T: Caldow, R; Pucher, A Mirme, A Kittelson, D

    2003-08-24

    There has been increased interest in obtaining size distribution data during transient engine operation where both particle size and total number concentrations can change dramatically. Traditionally, the measurement of particle emissions from vehicles has been a compromise based on choosing between the conflicting needs of high time resolution or high particle size resolution for a particular measurement. Currently the most common technique for measuring submicrometer particle sizes is the Scanning Mobility Particle Sizer (SMPSTM) system. The SMPS system gives high size resolution but requires an aerosol to be stable over a long time period to make a particle size distribution measurement. A Condensation Particle Counter (CPC) is commonly used for fast time response measurements but is limited to measuring total concentration only. This paper describes a new instrument, the Engine Exhaust Particle SizerTM (EEPSTM) spectrometer, which has high time resolution and a reasonable size resolution. The EEPS was designed specifically for measuring engine exhaust and, like the SMPS system, uses a measurement based on electrical mobility. Particles entering the instrument are charged to a predictable level, then passed through an annular space where they are repelled outward by the voltage from a central column. When the particles reach electrodes on the outer cylindrical (a column of rings), they create a current that is measured by an electrometer on one or more of the rings. The electrometer currents are measured multiple times per second to give high time resolution. A sophisticated realtime inversion algorithm converts the currents to particle size and concentration for immediate display.

  6. NASA's Hypersonic Research Engine Project: A review

    NASA Technical Reports Server (NTRS)

    Andrews, Earl H.; Mackley, Ernest A.

    1994-01-01

    The goals of the NASA Hypersonic Research Engine (HRE) Project, which began in 1964, were to design, develop, and construct a high-performance hypersonic research ramjet/scramjet engine for flight tests of the developed concept over the speed range of Mach 4 to 8. The project was planned to be accomplished in three phases: project definition, research engine development, and flight test using the X-15A-2 research airplane, which was modified to carry hydrogen fuel for the research engine. The project goal of an engine flight test was eliminated when the X-15 program was canceled in 1968. Ground tests of full-scale engine models then became the focus of the project. Two axisymmetric full-scale engine models, having 18-inch-diameter cowls, were fabricated and tested: a structural model and combustion/propulsion model. A brief historical review of the project, with salient features, typical data results, and lessons learned, is presented. An extensive number of documents were generated during the HRE Project and are listed.

  7. Visualization of Air Particle Dynamics in an Engine Inertial Particle Separator

    NASA Astrophysics Data System (ADS)

    Wolf, Jason; Zhang, Wei

    2015-11-01

    Unmanned Aerial Vehicles (UAVs) are regularly deployed around the world in support of military, civilian and humanitarian efforts. Due to their unique mission profiles, these advanced UAVs utilize various internal combustion engines, which consume large quantities of air. Operating these UAVs in areas with high concentrations of sand and dust can be hazardous to the engines, especially during takeoff and landing. In such events, engine intake filters quickly become saturated and clogged with dust particles, causing a substantial decrease in the UAVs' engine performance and service life. Development of an Engine Air Particle Separator (EAPS) with high particle separation efficiency is necessary for maintaining satisfactory performance of the UAVs. Inertial Particle Separators (IPS) have been one common effective method but they experience complex internal particle-laden flows that are challenging to understand and model. This research employs an IPS test rig to simulate dust particle separation under different flow conditions. Soda lime glass spheres with a mean diameter of 35-45 microns are used in experiments as a surrogate for airborne particulates encountered during flight. We will present measurements of turbulent flow and particle dynamics using flow visualization techniques to understand the multiphase fluid dynamics in the IPS device. This knowledge can contribute to design better performing IPS systems for UAVs. Cleveland State University, Cleveland, Ohio, 44115.

  8. Nuclear physics in particle therapy: a review

    NASA Astrophysics Data System (ADS)

    Durante, Marco; Paganetti, Harald

    2016-09-01

    Charged particle therapy has been largely driven and influenced by nuclear physics. The increase in energy deposition density along the ion path in the body allows reducing the dose to normal tissues during radiotherapy compared to photons. Clinical results of particle therapy support the physical rationale for this treatment, but the method remains controversial because of the high cost and of the lack of comparative clinical trials proving the benefit compared to x-rays. Research in applied nuclear physics, including nuclear interactions, dosimetry, image guidance, range verification, novel accelerators and beam delivery technologies, can significantly improve the clinical outcome in particle therapy. Measurements of fragmentation cross-sections, including those for the production of positron-emitting fragments, and attenuation curves are needed for tuning Monte Carlo codes, whose use in clinical environments is rapidly increasing thanks to fast calculation methods. Existing cross sections and codes are indeed not very accurate in the energy and target regions of interest for particle therapy. These measurements are especially urgent for new ions to be used in therapy, such as helium. Furthermore, nuclear physics hardware developments are frequently finding applications in ion therapy due to similar requirements concerning sensors and real-time data processing. In this review we will briefly describe the physics bases, and concentrate on the open issues.

  9. Nuclear physics in particle therapy: a review.

    PubMed

    Durante, Marco; Paganetti, Harald

    2016-09-01

    Charged particle therapy has been largely driven and influenced by nuclear physics. The increase in energy deposition density along the ion path in the body allows reducing the dose to normal tissues during radiotherapy compared to photons. Clinical results of particle therapy support the physical rationale for this treatment, but the method remains controversial because of the high cost and of the lack of comparative clinical trials proving the benefit compared to x-rays. Research in applied nuclear physics, including nuclear interactions, dosimetry, image guidance, range verification, novel accelerators and beam delivery technologies, can significantly improve the clinical outcome in particle therapy. Measurements of fragmentation cross-sections, including those for the production of positron-emitting fragments, and attenuation curves are needed for tuning Monte Carlo codes, whose use in clinical environments is rapidly increasing thanks to fast calculation methods. Existing cross sections and codes are indeed not very accurate in the energy and target regions of interest for particle therapy. These measurements are especially urgent for new ions to be used in therapy, such as helium. Furthermore, nuclear physics hardware developments are frequently finding applications in ion therapy due to similar requirements concerning sensors and real-time data processing. In this review we will briefly describe the physics bases, and concentrate on the open issues. PMID:27540827

  10. Ice Particle Analysis of the Honeywell AL502 Engine Booster

    NASA Technical Reports Server (NTRS)

    Bidwell, Colin S.; Rigby, David L.

    2015-01-01

    A flow and ice particle trajectory analysis was performed for the booster of the Honeywell ALF502 engine. The analysis focused on two closely related conditions one of which produced an icing event and another which did not during testing of the ALF502 engine in the Propulsion Systems Lab (PSL) at NASA Glenn Research Center. The flow analysis was generated using the NASA Glenn GlennHT flow solver and the particle analysis was generated using the NASA Glenn LEWICE3D v3.63 ice accretion software. The inflow conditions for the two conditions were similar with the main differences being that the condition that produced the icing event was 6.8 K colder than the non-icing event case and the inflow ice water content (IWC) for the non-icing event case was 50% less than for the icing event case. The particle analysis, which considered sublimation, evaporation and phase change, was generated for a 5 micron ice particle with a sticky impact model and for a 24 micron median volume diameter (MVD), 7 bin ice particle distribution with a supercooled large droplet (SLD) splash model used to simulate ice particle breakup. The particle analysis did not consider the effect of the runback and re-impingement of water resulting from the heated spinner and anti-icing system. The results from the analysis showed that the amount of impingement for the components were similar for the same particle size and impact model for the icing and non-icing event conditions. This was attributed to the similar aerodynamic conditions in the booster for the two cases. The particle temperature and melt fraction were higher at the same location and particle size for the non-icing event than for the icing event case due to the higher incoming inflow temperature for the non-event case. The 5 micron ice particle case produced higher impact temperatures and higher melt fractions on the components downstream of the fan than the 24 micron MVD case because the average particle size generated by the particle

  11. Human factors engineering program review model

    SciTech Connect

    Not Available

    1994-07-01

    The staff of the Nuclear Regulatory Commission is performing nuclear power plant design certification reviews based on a design process plan that describes the human factors engineering (HFE) program elements that are necessary and sufficient to develop an acceptable detailed design specification and an acceptable implemented design. There are two principal reasons for this approach. First, the initial design certification applications submitted for staff review did not include detailed design information. Second, since human performance literature and industry experiences have shown that many significant human factors issues arise early in the design process, review of the design process activities and results is important to the evaluation of an overall design. However, current regulations and guidance documents do not address the criteria for design process review. Therefore, the HFE Program Review Model (HFE PRM) was developed as a basis for performing design certification reviews that include design process evaluations as well as review of the final design. A central tenet of the HFE PRM is that the HFE aspects of the plant should be developed, designed, and evaluated on the basis of a structured top-down system analysis using accepted HFE principles. The HFE PRM consists of ten component elements. Each element in divided into four sections: Background, Objective, Applicant Submittals, and Review Criteria. This report describes the development of the HFE PRM and gives a detailed description of each HFE review element.

  12. Automotive Stirling Engine Mod I design review report. Volume III

    SciTech Connect

    Not Available

    1982-08-01

    This volume, No. 3, of the Automotive Stirling Engine Mod 1 Design Review Report contains a preliminary parts list and detailed drawings of equipment for the basic Stirling engine and for the following systems: vehicular Stirling Engine System; external heat system; hot and cold engine systems; engine drive; controls and auxiliaries; and vehicle integration. (LCL)

  13. Particle based plasma simulation for an ion engine discharge chamber

    NASA Astrophysics Data System (ADS)

    Mahalingam, Sudhakar

    Design of the next generation of ion engines can benefit from detailed computer simulations of the plasma in the discharge chamber. In this work a complete particle based approach has been taken to model the discharge chamber plasma. This is the first time that simplifying continuum assumptions on the particle motion have not been made in a discharge chamber model. Because of the long mean free paths of the particles in the discharge chamber continuum models are questionable. The PIC-MCC model developed in this work tracks following particles: neutrals, singly charged ions, doubly charged ions, secondary electrons, and primary electrons. The trajectories of these particles are determined using the Newton-Lorentz's equation of motion including the effects of magnetic and electric fields. Particle collisions are determined using an MCC statistical technique. A large number of collision processes and particle wall interactions are included in the model. The magnetic fields produced by the permanent magnets are determined using Maxwell's equations. The electric fields are determined using an approximate input electric field coupled with a dynamic determination of the electric fields caused by the charged particles. In this work inclusion of the dynamic electric field calculation is made possible by using an inflated plasma permittivity value in the Poisson solver. This allows dynamic electric field calculation with minimal computational requirements in terms of both computer memory and run time. In addition, a number of other numerical procedures such as parallel processing have been implemented to shorten the computational time. The primary results are those modeling the discharge chamber of NASA's NSTAR ion engine at its full operating power. Convergence of numerical results such as total number of particles inside the discharge chamber, average energy of the plasma particles, discharge current, beam current and beam efficiency are obtained. Steady state results for

  14. Optical measurement of gas turbine engine soot particle effluents

    SciTech Connect

    Litchford, R.J.; Sun, F.; Few, J.D.; Lewis, J.W.L.

    1998-01-01

    This paper addresses optical-based techniques for measuring soot particulate loading in the exhaust stream of gas turbine engines. The multi-angle scattering and multi-wavelength extinction of light beams by ensembles of submicrometer soot particles was investigated as a diagnostic means of inferring particle field characteristics. That is, the particle size distribution function and particle number density were deduced using an innovative downhill simplex inversion algorithm for fitting the deconvolved Mie-based scattering/extinction integral to the measured scattering/extinction signals. In this work, the particle size distribution was characterized by the widely accepted two-parameter log-normal distribution function, which is fully defined with the specification of the mean particle diameter and the standard deviation of the distribution. The accuracy and precision of the algorithm were evaluated for soot particle applications by applying the technique to noise-perturbed synthetic data in which the signal noise component is obtained by Monte Carlo sampling of Gaussian distributed experimental errors of 4, 6, and 10%. The algorithm was shown to yield results having an inaccuracy of less than 10% for the highest noise levels and an imprecision equal to or less than the experimental error. Multi-wavelength extinction experiments with a laboratory bench-top burner yielded a mean particle diameter of 0.039 {micro}m and indicated that molecular absorption by organic vapor-phase molecules in the ultraviolet region should not significantly influence the measurements. A field demonstration test was conducted on one of the JT-12D engines of a Sabre Liner jet aircraft. This experiment yielded mean diameters of 0.040 {micro}m and 0.036 {micro}m and standard deviations of 0.032 {micro}m for scattering and extinction methods, respectively. The total particulate mass flow rate at idle was estimated to be 0.54 kg/h.

  15. Strain engineering of graphene: a review

    NASA Astrophysics Data System (ADS)

    Si, Chen; Sun, Zhimei; Liu, Feng

    2016-02-01

    Graphene has intrigued the science community by many unique properties not found in conventional materials. In particular, it is the strongest two-dimensional material ever measured, being able to sustain reversible tensile elastic strain larger than 20%, which yields an interesting possibility to tune the properties of graphene by strain and thus opens a new field called ``straintronics''. In this article, the current progress in the strain engineering of graphene is reviewed. We first summarize the strain effects on the electronic structure and Raman spectra of graphene. We then highlight the electron-phonon coupling greatly enhanced by the biaxial strain and the strong pseudomagnetic field induced by the non-uniform strain with specific distribution. Finally, the potential application of strain-engineering in the self-assembly of foreign atoms on the graphene surface is also discussed. Given the short history of graphene straintronics research, the current progress has been notable, and many further advances in this field are expected.

  16. A Review of Methods for Evaluating Particle Stability in Suspension Based Pressurized Metered Dose Inhalers.

    PubMed

    D'Sa, Dexter; Chan, Hak-Kim

    2015-01-01

    Advances in particle engineering techniques, such as spray drying, freeze drying and supercritical fluid precipitation, have greatly enhanced the ability to control the structure, morphology, and solid state phase of inhalable sized particles (1 - 5 µm) for formulation in pressurized metered dose inhalers (pMDI). To optimize the properties of these engineered particles for formulation in hydrofluoroalkane propellants (HFA 134a / 227) it is necessary to measure both bulk and individual particle properties before, after, and during formulation. This review examines established and recently developed methods for evaluating a variety of particle properties including but not limited to size, surface and internal morphology, chemical composition, and solid state phase. Novel methods for evaluating particle physical and chemical stability directly in propellant or similar environments are also discussed. PMID:26290200

  17. Multivariable optimization of liquid rocket engines using particle swarm algorithms

    NASA Astrophysics Data System (ADS)

    Jones, Daniel Ray

    Liquid rocket engines are highly reliable, controllable, and efficient compared to other conventional forms of rocket propulsion. As such, they have seen wide use in the space industry and have become the standard propulsion system for launch vehicles, orbit insertion, and orbital maneuvering. Though these systems are well understood, historical optimization techniques are often inadequate due to the highly non-linear nature of the engine performance problem. In this thesis, a Particle Swarm Optimization (PSO) variant was applied to maximize the specific impulse of a finite-area combustion chamber (FAC) equilibrium flow rocket performance model by controlling the engine's oxidizer-to-fuel ratio and de Laval nozzle expansion and contraction ratios. In addition to the PSO-controlled parameters, engine performance was calculated based on propellant chemistry, combustion chamber pressure, and ambient pressure, which are provided as inputs to the program. The performance code was validated by comparison with NASA's Chemical Equilibrium with Applications (CEA) and the commercially available Rocket Propulsion Analysis (RPA) tool. Similarly, the PSO algorithm was validated by comparison with brute-force optimization, which calculates all possible solutions and subsequently determines which is the optimum. Particle Swarm Optimization was shown to be an effective optimizer capable of quick and reliable convergence for complex functions of multiple non-linear variables.

  18. Brake wear particle emissions: a review.

    PubMed

    Grigoratos, Theodoros; Martini, Giorgio

    2015-02-01

    Traffic-related sources have been recognized as a significant contributor of particulate matter particularly within major cities. Exhaust and non-exhaust traffic-related sources are estimated to contribute almost equally to traffic-related PM10 emissions. Non-exhaust particles can be generated either from non-exhaust sources such as brake, tyre, clutch and road surface wear or already exist in the form of deposited material at the roadside and become resuspended due to traffic-induced turbulence. Among non-exhaust sources, brake wear can be a significant particulate matter (PM) contributor, particularly within areas with high traffic density and braking frequency. Studies mention that in urban environments, brake wear can contribute up to 55 % by mass to total non-exhaust traffic-related PM10 emissions and up to 21 % by mass to total traffic-related PM10 emissions, while in freeways, this contribution is lower due to lower braking frequency. As exhaust emissions control become stricter, relative contributions of non-exhaust sources-and therefore brake wear-to traffic-related emissions will become more significant and will raise discussions on possible regulatory needs. The aim of the present literature review study is to present the state-of-the-art of the different aspects regarding PM resulting from brake wear and provide all the necessary information in terms of importance, physicochemical characteristics, emission factors and possible health effects. PMID:25318420

  19. Exhaust particle removing system for an internal combustion engine

    SciTech Connect

    Shinzawa, M.

    1986-08-05

    An exhaust particle removing system is described for an internal combustion engine, comprising: (a) a filter disposed in an engine exhaust passage for trapping particles suspended in exhaust gas; (b) a burner for burning off the particles deposited on the filter; (c) means for sensing the pressure in the exhaust passage at a point upstream of the filter; (d) means for sensing the pressure in the exhaust passage at a point downstream of the filter; (e) means for determining whether or not the sensed upstream pressure is lower than a preset level; (f) means for, when the sensed upstream pressure is not lower than the preset level, deducing the degree of clogging of the filter on the basis of the sensed upstream and downstream pressures; (g) means for, when the sensed upstream pressure is lower than the preset level, measuring a time elapsed since the moment at which the sensed upstream pressure dropped below the preset level; (h) means for, when the sensed upstream pressure is lower than the preset level, deducing the degree of clogging of the filter on the basis of the time elapsed and the sensed upstream and downstream pressures obtained immediately prior to the moment at which the sensed upstream pressure dropped below the preset level; and (i) means for controlling the burner on the basis of the deduced degree of clogging of the filter.

  20. Review: The future of cystatin engineering.

    PubMed

    van Wyk, Stefan G; Kunert, Karl J; Cullis, Christopher A; Pillay, Priyen; Makgopa, Matome E; Schlüter, Urte; Vorster, Barend J

    2016-05-01

    Plant cystatins are naturally occurring protease inhibitors that prevent proteolysis by papain-like cysteine proteases. Their protective action against environmental stresses has been relatively well characterised. Still, there is a need to greatly improve both potency and specificity based on the current rather poor performance of cystatins in biotechnological applications. Research in creating more potent and specific cystatins, including amino acid substitutions in either conserved cystatin motifs and/or at variable amino acid sites, is reviewed. Existing gaps for better understanding of cystatin-protease interactions are further explored. Current knowledge on multi-cystatins or hybrid protease inhibitors involving cystatins as an additional option for cystatin engineering is further outlined along with the nuances of how cystatins with rather unusual amino acid sequences might actually help in cystatin engineering. Finally, future opportunities for application of cystatins are highlighted which include applications in genetically modified transgenic plants for environmental stress protection and also as nutraceuticals, as part of more nutritious food. Further opportunities might also include the possible management of diseases and disorders, often associated with lifestyle changes, and the most immediate and promising application which is inclusion into plant-based recombinant protein production platforms. PMID:26993242

  1. Strain engineering of graphene: a review.

    PubMed

    Si, Chen; Sun, Zhimei; Liu, Feng

    2016-02-14

    Graphene has intrigued the science community by many unique properties not found in conventional materials. In particular, it is the strongest two-dimensional material ever measured, being able to sustain reversible tensile elastic strain larger than 20%, which yields an interesting possibility to tune the properties of graphene by strain and thus opens a new field called "straintronics". In this article, the current progress in the strain engineering of graphene is reviewed. We first summarize the strain effects on the electronic structure and Raman spectra of graphene. We then highlight the electron-phonon coupling greatly enhanced by the biaxial strain and the strong pseudomagnetic field induced by the non-uniform strain with specific distribution. Finally, the potential application of strain-engineering in the self-assembly of foreign atoms on the graphene surface is also discussed. Given the short history of graphene straintronics research, the current progress has been notable, and many further advances in this field are expected. PMID:26796960

  2. EXPOSURE TO CONCENTRATED AMBIENT PARTICLES (CAPS): REVIEW

    EPA Science Inventory

    Epidemiologic studies support a participation of fine particulate matter (PM) with a diameter of 0.1 to 2.5 microm in the effects of air pollution particles on human health. The ambient fine particle concentrator is a recently developed technology that can enrich the mass of ambi...

  3. Review on antibacterial characteristics of bridge engineering biomaterials.

    PubMed

    Zhao, Qing-Qing; Chen, Meng-Yao; He, Rui-Lin; Zhang, Zhong-Feng; Ashraf, Muhammad Aqeel

    2016-01-01

    This review summarizes the research on timber construction materials used in bridge construction. It focuses on the application of antiseptic treatments and the use of timber engineering materials in decks and bridges. This review also provides an overview on the future research and prospects of engineered timber materials. PMID:26858558

  4. Review on antibacterial characteristics of bridge engineering biomaterials

    PubMed Central

    Zhao, Qing-qing; Chen, Meng-yao; He, Rui-lin; Zhang, Zhong-feng; Ashraf, Muhammad Aqeel

    2015-01-01

    This review summarizes the research on timber construction materials used in bridge construction. It focuses on the application of antiseptic treatments and the use of timber engineering materials in decks and bridges. This review also provides an overview on the future research and prospects of engineered timber materials. PMID:26858558

  5. BOOK REVIEW: Particle Astrophysics (Second Edition)

    NASA Astrophysics Data System (ADS)

    Bell, Nicole

    2009-07-01

    Particle astrophysics, the interface of elementary particle physics with astrophysics and cosmology, is a rapidly evolving field. Perkins' book provides a nice introduction to this field, at a level appropriate for senior undergraduate students. Perkins develops the foundations underlying both the particle and astrophysics areas, and also covers some of the most recent developments in this field. The latter is an appealing feature, as students rarely encounter topics of current research in their undergraduate textbooks. Part 1 of the text introduces the elementary particle content, and interactions, of the standard model of particle physics. Relativity is addressed at the level of special relativistic kinematics, the equivalence principle and the Robertson-Walker metric. Part 2 covers cosmology, starting with the expansion of the Universe and basic thermodynamics. It then moves on to primordial nucleosynthesis, baryogenesis, dark matter, dark energy, structure formation and the cosmic microwave background. Part 3 covers cosmic rays, stellar evolution, and related topics. Cutting edge topics include the use of the cosmological large scale structure power spectrum to constrain neutrino mass, the creation of the baryon asymmetry via leptogenesis, and the equation of state for dark energy. While the treatment of many topics is quite brief, the level of depth is about right for undergraduates who are being exposed to these topics for the first time. The breadth of topics spanned is excellent. Perkins does a good job connecting theory with the experimental underpinnings, and of simplifying the theoretical presentation of complex subjects to a level that senior undergraduate students should find accessible. Each chapter includes a number of exercises. Brief solutions are provided for all the exercises, while fully worked solutions are provided for a smaller subset.

  6. Integration of active pharmaceutical ingredient solid form selection and particle engineering into drug product design.

    PubMed

    Ticehurst, Martyn David; Marziano, Ivan

    2015-06-01

    This review seeks to offer a broad perspective that encompasses an understanding of the drug product attributes affected by active pharmaceutical ingredient (API) physical properties, their link to solid form selection and the role of particle engineering. While the crucial role of active pharmaceutical ingredient (API) solid form selection is universally acknowledged in the pharmaceutical industry, the value of increasing effort to understanding the link between solid form, API physical properties and drug product formulation and manufacture is now also being recognised. A truly holistic strategy for drug product development should focus on connecting solid form selection, particle engineering and formulation design to both exploit opportunities to access simpler manufacturing operations and prevent failures. Modelling and predictive tools that assist in establishing these links early in product development are discussed. In addition, the potential for differences between the ingoing API physical properties and those in the final product caused by drug product processing is considered. The focus of this review is on oral solid dosage forms and dry powder inhaler products for lung delivery. PMID:25677227

  7. Automotive Stirling engine system component review

    NASA Technical Reports Server (NTRS)

    Hindes, Chip; Stotts, Robert

    1987-01-01

    The design and testing of the power and combustion control system for the basic Stirling engine, Mod II, are examined. The power control system is concerned with transparent operation, and the Mod II uses engine working gas pressure variation to control the power output of the engine. The main components of the power control system, the power control valve, the pump-down system, and the hydrogen stable system, are described. The combustion control system consists of a combustion air supply system and an air/fuel ratio control system, and the system is to maintain constant heater head temperature, and to maximize combustion efficiency and to minimize exhaust emissions.

  8. Review of Aircraft Engine Fan Noise Reduction

    NASA Technical Reports Server (NTRS)

    VanZante, Dale

    2008-01-01

    Aircraft turbofan engines incorporate multiple technologies to enhance performance and durability while reducing noise emissions. Both careful aerodynamic design of the fan and proper installation of the fan into the system are requirements for achieving the performance and acoustic objectives. The design and installation characteristics of high performance aircraft engine fans will be discussed along with some lessons learned that may be applicable to spaceflight fan applications.

  9. The JSC Engineering Directorate Product Peer Review Process

    NASA Technical Reports Server (NTRS)

    Jenks, Kenneth C.

    2009-01-01

    The JSC Engineering Directorate has developed a Product Peer Review process in support of NASA policies for project management and systems engineering. The process complies with the requirements of NPR 7120.5, NPR 7123.1 and NPR 7150.2 and follows the guidance in NASA/SP-2007-6105. This presentation will give an overview of the process followed by a brief demonstration of an actual peer review, with audience participation.

  10. A Study of Technical Engineering Peer Reviews at NASA

    NASA Technical Reports Server (NTRS)

    Chao, Lawrence P.; Tumer, Irem Y.; Bell, David G.

    2003-01-01

    This report describes the state of practices of design reviews at NASA and research into what can be done to improve peer review practices. There are many types of reviews at NASA: required and not, formalized and informal, programmatic and technical. Standing project formal reviews such as the Preliminary Design Review and Critical Design Review are a required part of every project and mission development. However, the technical, engineering peer reviews that support teams' work on such projects are informal, some times ad hoc, and inconsistent across the organization. The goal of this work is to identify best practices and lessons learned from NASA's experience, supported by academic research and methodologies to ultimately improve the process. This research has determined that the organization, composition, scope, and approach of the reviews impact their success. Failure Modes and Effects Analysis (FMEA) can identify key areas of concern before or in the reviews. Product definition tools like the Project Priority Matrix, engineering-focused Customer Value Chain Analysis (CVCA), and project or system-based Quality Function Deployment (QFD) help prioritize resources in reviews. The use of information technology and structured design methodologies can strengthen the engineering peer review process to help NASA work towards error-proofing the design process.

  11. Diesel Engine performance improvement in a 1-D engine model using Particle Swarm Optimization

    NASA Astrophysics Data System (ADS)

    Karra, Prashanth

    2015-12-01

    A particle swarm optimization (PSO) technique was implemented to improve the engine development and optimization process to simultaneously reduce emissions and improve the fuel efficiency. The optimization was performed on a 4-stroke 4-cylinder GT-Power based 1-D diesel engine model. To achieve the multi-objective optimization, a merit function was defined which included the parameters to be optimized: Nitrogen Oxides (NOx), Nonmethyl hydro carbons (NMHC), Carbon Monoxide (CO), Brake Specific Fuel Consumption (BSFC). EPA Tier 3 emissions standards for non-road diesel engines between 37 and 75 kW of output were chosen as targets for the optimization. The combustion parameters analyzed in this study include: Start of main Injection, Start of Pilot Injection, Pilot fuel quantity, Swirl, and Tumble. The PSO was found to be very effective in quickly arriving at a solution that met the target criteria as defined in the merit function. The optimization took around 40-50 runs to find the most favourable engine operating condition under the constraints specified in the optimization. In a favourable case with a high merit function values, the NOx+NMHC and CO values were reduced to as low as 2.9 and 0.014 g/kWh, respectively. The operating conditions at this point were: 10 ATDC Main SOI, -25 ATDC Pilot SOI, 0.25 mg of pilot fuel, 0.45 Swirl and 0.85 tumble. These results indicate that late main injections preceded by a close, small pilot injection are most favourable conditions at the operating condition tested.

  12. Influence of diesel engine combustion parameters on primary soot particle diameter.

    PubMed

    Mathis, Urs; Mohr, Martin; Kaegi, Ralf; Bertola, Andrea; Boulouchos, Konstantinos

    2005-03-15

    Effects of engine operating parameters and fuel composition on both primary soot particle diameter and particle number size distribution in the exhaust of a direct-injected heavy-duty diesel engine were studied in detail. An electrostatic sampler was developed to deposit particles directly on transmission electron microscopy (TEM) grids. Using TEM, the projected area equivalent diameter of primary soot particles was determined. A scanning mobility particle sizer (SMPS) was used for the measurement of the particle number size distribution. Variations in the main engine operating parameters (fuel injection system, air management, and fuel properties) were made to investigate soot formation and oxidation processes. Primary soot particle diameters determined by TEM measurements ranged from 17.5 to 32.5 nm for the diesel fuel and from 24.1 to 27.2 nm for the water-diesel emulsion fuel depending on the engine settings. For constant fuel energy flow rate, the primary particle size from the water-diesel emulsion fuel was slightly larger than that from the diesel fuel. A reduction in primary soot particle diameter was registered when increasing the fuel injection pressure (IP) or advancing the start of injection (SOI). Larger primary soot particle diameters were measured while the engine was operating with exhaust gas recirculation (EGR). Heat release rate analysis of the combustion process revealed that the primary soot particle diameter decreased when the maximum flame temperature increased for the diesel fuel. PMID:15819252

  13. Ethanol Blends and Engine Operating Strategy Effects on Light-Duty Spark-Ignition Engine Particle Emissions

    SciTech Connect

    Szybist, James P; Youngquist, Adam D; Barone, Teresa L; Storey, John Morse; Moore, Wayne; Foster, Matthew; Confer, Keith

    2011-01-01

    Spark ignition (SI) engines with direct injection (DI) fueling can improve fuel economy and vehicle power beyond that of port fuel injection (PFI). Despite this distinct advantage, DI fueling often increases particle emissions such that SI exhaust may be subject to future particle emissions regulations. Challenges in controlling particle emissions arise as engines encounter varied fuel composition such as intermediate ethanol blends. Furthermore, modern engines are operated using unconventional breathing strategies with advanced cam-based variable valve actuation systems. In this study, we investigate particle emissions from a multi-cylinder DI engine operated with three different breathing strategies, fueling strategies and fuels. The breathing strategies are conventional throttled operation, early intake valve closing (EIVC) and late intake valve closing (LIVC); the fueling strategies are single injection DI (sDI), multi-injection DI (mDI), and PFI; and the fuels are emissions certification gasoline, E20 and E85. The results indicate the dominant factor influencing particle number concentration emissions for the sDI and mDI strategies is the fuel injection timing. Overly advanced injection timing results in particle formation due to fuel spray impingement on the piston, and overly retarded injection timing results in particle formation due to poor fuel and air mixing. In addition, fuel type has a significant effect on particle emissions for the DI fueling strategies. Gasoline and E20 fuels generate comparable levels of particle emissions, but E85 produces dramatically lower particle number concentration. The particle emissions for E85 are near the detection limit for the FSN instrument, and particle number emissions are one to two orders of magnitude lower for E85 relative to gasoline and E20. We found PFI fueling produces very low levels of particle emissions under all conditions and is much less sensitive to engine breathing strategy and fuel type than the DI

  14. Emission of ultrafine particles from the incineration of municipal solid waste: A review

    NASA Astrophysics Data System (ADS)

    Jones, Alan M.; Harrison, Roy M.

    2016-09-01

    Ultrafine particles (diameter <100 nm) are of great topical interest because of concerns over possible enhanced toxicity relative to larger particles of the same composition. While combustion processes, and especially road traffic exhaust are a known major source of ultrafine particle emissions, relatively little is known of the magnitude of emissions from non-traffic sources. One such source is the incineration of municipal waste, and this article reviews studies carried out on the emissions from modern municipal waste incinerators. The effects of engineering controls upon particle emissions are considered, as well as the very limited information on the effects of changing waste composition. The results of measurements of incinerator flue gas, and of atmospheric sampling at ground level in the vicinity of incinerators, show that typical ultrafine particle concentrations in flue gas are broadly similar to those in urban air and that consequently, after the dispersion process dilutes incinerator exhaust with ambient air, ultrafine particle concentrations are typically indistinguishable from those that would occur in the absence of the incinerator. In some cases the ultrafine particle concentration in the flue gas may be below that in the local ambient air. This appears to be a consequence of the removal of semi-volatile vapours in the secondary combustion zone and abatement plant, and the high efficiency of fabric filters for ultrafine particle collection.

  15. Allison engine ATS program technical review

    SciTech Connect

    Mukavetz, D.

    1995-12-31

    Gas turbines in industrial and utility applications can help meet future national and worldwide power generation requirements. Implementation of the ATS Program will also keep U.S. manufacturers on the cutting edge of turbine technology for power generation applications and enhance the nation`s economic competitiveness. Allison`s ATS addresses the program goals in the following manner: (1) Efficiency - The turbine selected for the ATS uses Allison`s latest single crystal alloys incorporating the most efficient component cooling technology Allison has developed. These features allow the turbine to operate at a rotor inlet temperature (RIT) of 1427{degrees}C (2600{degrees}F). The compression system for this engine has an overall pressure ratio of more than 20:1 and is based on technology previously demonstrated at Allison. The engine that uses these components will demonstrate a thermal efficiency that is 18% better than the best in class today. (2) Environment - The combustion system selected for this engine incorporates a catalytically stabilized, lean premix system with ceramic components requiring no significant wall cooling. This system will achieve acceptance in severe nonattainment areas, producing less than 8 ppm for oxides of nitrogen (NOx), with acceptable carbon monoxide (CO) and unburned hydrocarbon (UHC). (3) Fuel Flexibility - Allison has production engines in commercial service that are operating on biomass fuels. Previous DOE-funded programs have allowed Allison to develop and demonstrate coal-fueled gas turbine technology. (4) Cost of Power - The busbar cost of energy for the Allison ATS ranges from 23.6 to 27.6% lower than the current state of the art for systems meeting ATS environmental requirements. (5) Reliability, Availability, and Maintainability - The Allison ATS will be designed to have high reliability and low maintenance costs. Critical components will be designed using Allison`s latest life analysis methods.

  16. Biomaterials in Tooth Tissue Engineering: A Review

    PubMed Central

    Sharma, Sarang; Srivastava, Dhirendra; Grover, Shibani; Sharma, Vivek

    2014-01-01

    Biomaterials play a crucial role in the field of tissue engineering. They are utilized for fabricating frameworks known as scaffolds, matrices or constructs which are interconnected porous structures that establish a cellular microenvironment required for optimal tissue regeneration. Several natural and synthetic biomaterials have been utilized for fabrication of tissue engineering scaffolds. Amongst different biomaterials, polymers are the most extensively experimented and employed materials. They can be tailored to provide good interconnected porosity, large surface area, adequate mechanical strengths, varying surface characterization and different geometries required for tissue regeneration. A single type of material may however not meet all the requirements. Selection of two or more biomaterials, optimization of their physical, chemical and mechanical properties and advanced fabrication techniques are required to obtain scaffold designs intended for their final application. Current focus is aimed at designing biomaterials such that they will replicate the local extra cellular environment of the native organ and enable cell-cell and cell-scaffold interactions at micro level required for functional tissue regeneration. This article provides an insight into the different biomaterials available and the emerging use of nano engineering principles for the construction of bioactive scaffolds in tooth regeneration. PMID:24596804

  17. Abiotic soil changes induced by engineered nanomaterials: A critical review.

    PubMed

    Dror, Ishai; Yaron, Bruno; Berkowitz, Brian

    2015-10-01

    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. It is clear from these publications that soil is a major sink for ENMs, and that only a small portion degrades or is mobilized further into groundwater. However, to date, very few studies have examined the impact of ENMs on the natural soil-subsurface matrix and its properties. Moreover, it is now well accepted that chemical contaminants are capable of changing soil properties either by inducing direct chemical or physical changes, or through indirect changes by, e.g., influencing biological activity that in turn modifies soil properties. Here, we review studies on the deposition, retention, and accumulation of ENMs in soil, indicative of the extent to which soil acts as a major sink of ENMs. We then examine evidence of how these retained particles lead to modification of surface properties, which are manifested by changes in the sorption capacity of soil for other (organic and inorganic) solutes, and by surface charges and composition different than the natural surfaces. Finally, we demonstrate how this results in physical and hydrological changes to soil properties, including hydraulic conductivity, swelling capacity and wettability. The overall picture revealed in this critical review sheds light on a perspective that has received little attention thus far. These aspects of soil change, due to exposure and subsequent accumulation of ENMs, may ultimately prove to be one of the most important impacts of ENM releases to the environment. PMID:25913535

  18. Tissue engineering in periodontal regeneration: A brief review

    PubMed Central

    Dabra, Sarita; Chhina, Kamalpreet; Soni, Nitin; Bhatnagar, Rakhi

    2012-01-01

    Periodontal disease is a major public health issue and the development of effective therapies to treat the disease and regenerate periodontal tissue is an important goal of today's medicine. Regeneration of periodontal tissue is perhaps one of the most complex process to occur in the body. Langer and colleagues proposed tissue engineering as a possible technique for regenerating the lost periodontal tissues. Tissue engineering is a multidisciplinary field, which involves the application of the principles and methods of engineering and life sciences to help in the development of biological substitutes to restore, maintain or improve the function of damaged tissues and organs. A Google/Medline search was conducted and relevant literature evaluating the potential role of the tissue engineering in periodontal regeneration, which included histological studies and controlled clinical trials, was reviewed. A comprehensive search was designed. The articles were independently screened for eligibility. Articles with authentic controls and proper randomization and pertaining specifically to their role in periodontal regeneration were included. The available literature was analyzed and compiled. The analysis indicate tissue engineering to be a promising, as well as an effective novel approach to reconstruct and engineer the periodontal apparatus. Here, we represent several articles, as well as recent texts that make up a special and an in-depth review on the subject. The purpose behind writing this brief review has been to integrate the evidence of research related to tissue engineering so as to implement them in our daily practice. PMID:23559940

  19. Review of aerospace engineering cost modelling: The genetic causal approach

    NASA Astrophysics Data System (ADS)

    Curran, R.; Raghunathan, S.; Price, M.

    2004-11-01

    The primary intention of this paper is to review the current state of the art in engineering cost modelling as applied to aerospace. This is a topic of current interest and in addressing the literature, the presented work also sets out some of the recognised definitions of cost that relate to the engineering domain. The paper does not attempt to address the higher-level financial sector but rather focuses on the costing issues directly relevant to the engineering process, primarily those of design and manufacture. This is of more contemporary interest as there is now a shift towards the analysis of the influence of cost, as defined in more engineering related terms; in an attempt to link into integrated product and process development (IPPD) within a concurrent engineering environment. Consequently, the cost definitions are reviewed in the context of the nature of cost as applicable to the engineering process stages: from bidding through to design, to manufacture, to procurement and ultimately, to operation. The linkage and integration of design and manufacture is addressed in some detail. This leads naturally to the concept of engineers influencing and controlling cost within their own domain rather than trusting this to financers who have little control over the cause of cost. In terms of influence, the engineer creates the potential for cost and in a concurrent environment this requires models that integrate cost into the decision making process.

  20. Characterization of particles from a marine engine operating at low loads

    NASA Astrophysics Data System (ADS)

    Anderson, Maria; Salo, Kent; Hallquist, Åsa M.; Fridell, Erik

    2015-01-01

    Particle emissions from a marine diesel engine operating at low loads with four different fuels were characterized with respect to particle number (PN) and particle mass (PM), size distribution, volatility and chemical composition. The four different fuels used were Swedish Environmental class 1 (MK1) and class 3 diesel (MK3), heavy fuel oil (HFO, 0.12 wt% S) and marine diesel oil (MDO, 0.52 wt% S). The measurements were performed for a marine diesel engine in a test-bed engine lab and the particle emissions were measured with an Engine Exhaust Particle Sizer and a Dust Monitor, giving the number concentrations in the size range of 5.6-560 nm and 300 nm to 20 μm, respectively. To quantify the amount of solid particles a thermodenuder was used. Additionally, filter samples were taken for gravimetric, black carbon (BC) and elemental analysis. The particle emissions showed a bimodal size distribution by number and the number concentrations were dominated by nanoparticles (diameter (Dp) < 50 nm). The nanoparticles measured were both primary and secondary particles, depending on fuel and engine load, while the particles with Dp > 50 nm generally were solid primary particles. Combustion of HFO resulted in the highest PN and PM concentrations. Emission factors (EFs) for PM and PN for both the total particle emissions and the fraction of primary, solid particles are presented for different fuels and loads. EFs for nitrogen oxides (NOx), BC and some elements (Ca, Fe, V, Ni, Zn) are presented as well. This study contributes to understanding particle emissions from potential future fuels as well as emissions in ports and coastal areas where lower engine loads are common.

  1. Milestones in Software Engineering and Knowledge Engineering History: A Comparative Review

    PubMed Central

    del Águila, Isabel M.; Palma, José; Túnez, Samuel

    2014-01-01

    We present a review of the historical evolution of software engineering, intertwining it with the history of knowledge engineering because “those who cannot remember the past are condemned to repeat it.” This retrospective represents a further step forward to understanding the current state of both types of engineerings; history has also positive experiences; some of them we would like to remember and to repeat. Two types of engineerings had parallel and divergent evolutions but following a similar pattern. We also define a set of milestones that represent a convergence or divergence of the software development methodologies. These milestones do not appear at the same time in software engineering and knowledge engineering, so lessons learned in one discipline can help in the evolution of the other one. PMID:24624046

  2. Milestones in software engineering and knowledge engineering history: a comparative review.

    PubMed

    del Águila, Isabel M; Palma, José; Túnez, Samuel

    2014-01-01

    We present a review of the historical evolution of software engineering, intertwining it with the history of knowledge engineering because "those who cannot remember the past are condemned to repeat it." This retrospective represents a further step forward to understanding the current state of both types of engineerings; history has also positive experiences; some of them we would like to remember and to repeat. Two types of engineerings had parallel and divergent evolutions but following a similar pattern. We also define a set of milestones that represent a convergence or divergence of the software development methodologies. These milestones do not appear at the same time in software engineering and knowledge engineering, so lessons learned in one discipline can help in the evolution of the other one. PMID:24624046

  3. Hydrogen engines based on liquid fuels, a review

    NASA Technical Reports Server (NTRS)

    Houseman, J.; Voecks, G. E.

    1981-01-01

    The concept of storing hydrogen as part of a liquid fuel, such as gasoline or methanol, and subsequent onboard generation of the hydrogen from such liquids, is reviewed. Hydrogen generation processes, such as steam reforming, partial oxidation, and thermal decomposition are evaluated in terms of theoretical potential and practical limitations, and a summary is presented on the major experimental work on conversion of gasoline and methanol. Results of experiments indicate that onboard hydrogen generation from methanol is technically feasible and will yield substantial improvements in fuel economy and emissions, especially if methanol decomposition is brought about by the use of engine exhaust heat; e.g., a methanol decomposition reactor of 3.8 provides hydrogen-rich gas for a 4 cylinder engine (1.952), and 80% of the methanol is converted, engine exhaust gas being the only heat supply. A preliminary outline of the development of a methanol-based hydrogen engine and a straight hydrogen engine is presented.

  4. Synthesis and engineering of polymeric latex particles for medical applications

    NASA Astrophysics Data System (ADS)

    Kim, Sangyup

    Latex particles with well-defined colloidal and surface characteristics have received increasing attention due to their useful applications in many areas, especially as solid phase supports in numerous biological applications such as immunoassay, DNA diagnostic, cell separation, and drug delivery carrier. Hemodialysis membrane using these particles would be another potential application for the advanced separation treatment for patients with end stage renal disease (ESRD). It is desirable to remove middle molecular weight proteins with minimal removal of other proteins such as albumin. Thus, it is necessary to understand the fundamental interactions between the particles and blood proteins to maximize the performance of these membranes. This improvement will have significant economic and health impact. The objective of this study is to synthesize polymeric latex particles of specific functionality to achieve the desired selective separation of target proteins from the human blood. Semi-continuous seed emulsion polymerization was used to prepare monodisperse polystyrene seed particles ranging from 126+/-7.5 to 216+/-5.3 nm in size, which are then enlarged by about 800nm. Surfactant amount played a key role in controlling the latex particle size. Negatively charged latex particles with a different hydrophobicity were prepared by introduction of a sodium persulfate initiator and hydrophilic acrylic acid monomer. The prepared polymeric particles include bare polystyrene (PS) particles, less hydrophobic PS core and PMMA shell particles, and more hydrophilic PS core and PMMA-co-PAA shell latex particles with a 370nm mean diameter. SEM, light scattering, and zeta potential measurements were used to characterize particle size and surface properties. Adsorption isotherms of two proteins, bovine serum albumin (BSA) and beta2-microglobulin (beta2M), on latex particles were obtained as a function of pH and ionic strength using the bicinchoninic acid (BCA) assay method. The

  5. Impulse Plasma In Surface Engineering - a review

    NASA Astrophysics Data System (ADS)

    Zdunek, K.; Nowakowska-Langier, K.; Chodun, R.; Okrasa, S.; Rabinski, M.; Dora, J.; Domanowski, P.; Halarowicz, J.

    2014-11-01

    The article describes the view of the plasma surface engineering, assuming the role of non-thermal energy effects in the synthesis of materials and coatings deposition. In the following study it was underlined that the vapor excitation through the application of an electric field during coatings deposition gives new possibilities for coatings formation. As an example the IPD method was chosen. During the IPD (Impulse Plasma Deposition) the impulse plasma is generated in the coaxial accelerator by strong periodic electrical pulses. The impulse plasma is distributed in the form of energetic plasma pockets. Due to the almost completely ionization of gas, the nucleation of new phases takes place on ions directly in the plasma itself. As a result the coatings of metastable materials with nano-amorphous structure and excellent adhesion to the non-heated intentionally substrates could be deposited. Recently the novel way of impulse plasma generation during the coatings deposition was proposed and developed by our group. An efficient tool for plasma process control, the plasma forming gas injection to the interelectrode space was used. Periodic changing the gas pressure results in increasing both the degree of dispersion and the dynamics of the plasma pulses. The advantage of the new technique in deposition of coatings with exceptionally good properties has been demonstrated in the industrial scale not only in the case of the IPD method but also in the case of very well known magnetron sputtering method.

  6. PARTICLE TRAP EFFECTS ON HEAVY-DUTY DIESEL ENGINE EMISSIONS

    EPA Science Inventory

    The ceramic trap used in this study was highly effective in reducing particle emissions in the diesel exhaust; the weight of emitted particles and their associated chemicals in the filtered exhaust was reduced by over 90% under the two different work loads. As a consequence...

  7. Internal combustion engine power. A quarter century in review

    SciTech Connect

    Kane, J.

    1994-04-01

    The advancements have been momentous. A review of the past quarter century of progress - including engine efficiencies, power ratings, fuels, emissions and the technological advances associated with these parameters - draws the real and outstanding developments of the period into perspective. Though the shapes of engines appear to be the same, few of the easy product classifications that existed in 1969 have survived to this day. In addition, the pattern of engine development is becoming similar throughout the world. All diesel engine design work, regardless of the country in which it is being carried out, is related to increasing specific output, from the smaller high-speed diesel, gas and gas turbine engines to the very largest stationary and marine power engines. This is being accomplished for the reciprocating engine by, basically, the same design and research techniques: higher speed, larger engine displacement through larger cylinder sizes, more cylinders with V-type configurations, and higher mean effective pressures through intensive use of turbo-charging and charge-air cooling, along with cylinder-head and injection process modifications. 6 figs.

  8. Human Factors Engineering Review Model for advanced nuclear power reactors

    SciTech Connect

    O'Hara, J.; Higgins, J. ); Goodman, C.; Galletti, G.: Eckenrode, R. )

    1993-01-01

    One of the major issues to emerge from the initial design reviews under the certification process was that detailed human-systems interface (HSI) design information was not available for staff review. To address the lack of design detail issue. The Nuclear Regulatory Commission (NRC) is performing the design certification reviews based on a design process plan which describes the human factors engineering (HFE) program elements that are necessary and sufficient to develop an acceptable detailed design specification. Since the review of a design process is unprecedented in the nuclear industry. The criteria for review are not addressed by current regulations or guidance documents and. therefore, had to be developed. Thus, an HFE Program Review Model was developed. This paper will describe the model's rationale, scope, objectives, development, general characteristics. and application.

  9. Human Factors Engineering Review Model for advanced nuclear power reactors

    SciTech Connect

    O`Hara, J.; Higgins, J.; Goodman, C.; Galletti, G.: Eckenrode, R.

    1993-05-01

    One of the major issues to emerge from the initial design reviews under the certification process was that detailed human-systems interface (HSI) design information was not available for staff review. To address the lack of design detail issue. The Nuclear Regulatory Commission (NRC) is performing the design certification reviews based on a design process plan which describes the human factors engineering (HFE) program elements that are necessary and sufficient to develop an acceptable detailed design specification. Since the review of a design process is unprecedented in the nuclear industry. The criteria for review are not addressed by current regulations or guidance documents and. therefore, had to be developed. Thus, an HFE Program Review Model was developed. This paper will describe the model`s rationale, scope, objectives, development, general characteristics. and application.

  10. CHEMICAL COMPOSITION OF EXHAUST PARTICLES FROM GAS TURBINE ENGINES

    EPA Science Inventory

    A program was conducted to chemically characterize particulate emissions from a current technology, high population, gas turbine engine. Attention was focused on polynuclear aromatic compounds, phenols, nitrosamines and total organics. Polynuclear aromatic hydrocarbons (PAH) were...

  11. Microfluidic ultrasonic particle separators with engineered node locations and geometries

    DOEpatents

    Rose, Klint A; Fisher, Karl A; Wajda, Douglas A; Mariella, Jr., Raymond P; Bailey, Christoppher; Dehlinger, Dietrich; Shusteff, Maxim; Jung, Byoungsok; Ness, Kevin D

    2014-05-20

    An ultrasonic microfluidic system includes a separation channel for conveying a sample fluid containing small particles and large particles, flowing substantially parallel, adjacent to a recovery fluid, with which it is in contact. An acoustic transducer produces an ultrasound standing wave, that generates a pressure field having at least one node of minimum pressure amplitude. An acoustic extension structure is located proximate to said separation channel for positioning said acoustic node off center in said acoustic area and concentrating the large particles in said recovery fluid stream.

  12. Microfluidic ultrasonic particle separators with engineered node locations and geometries

    SciTech Connect

    Rose, Klint A; Fisher, Karl A; Wajda, Douglas A; Mariella, Jr., Raymond P; Bailey, Christopher; Dehlinger, Dietrich; Shusteff, Maxim; Jung, Byoungsok; Ness, Kevin D

    2015-03-31

    An ultrasonic microfluidic system includes a separation channel for conveying a sample fluid containing small particles and large particles, flowing substantially parallel, adjacent to a recovery fluid, with which it is in contact. An acoustic transducer produces an ultrasound standing wave, that generates a pressure field having at least one node of minimum, pressure amplitude. An acoustic extension structure is located proximate to said separation channel for positioning said acoustic node off center in said acoustic area and concentrating the large particles in said recovery fluid stream.

  13. Microfluidic ultrasonic particle separators with engineered node locations and geometries

    DOEpatents

    Rose, Klint A.; Fisher, Karl A.; Wajda, Douglas A.; Mariella, Jr., Raymond P.; Bailey, Christopher; Dehlinger, Dietrich; Shusteff, Maxim; Jung, Byoungsok; Ness, Kevin D.

    2016-04-26

    An ultrasonic microfluidic system includes a separation channel for conveying a sample fluid containing small particles and large particles, flowing substantially parallel, adjacent to a recovery fluid, with which it is in contact. An acoustic transducer produces an ultrasound standing wave, that generates a pressure field having at least one node of minimum pressure amplitude. An acoustic extension structure is located proximate to said separation channel for positioning said acoustic node off center in said acoustic area and concentrating the large particles in said recovery fluid stream.

  14. Performance of a multilevel quantum heat engine of an ideal N-particle Fermi system.

    PubMed

    Wang, Rui; Wang, Jianhui; He, Jizhou; Ma, Yongli

    2012-08-01

    We generalize the quantum heat engine (QHE) model which was first proposed by Bender et al. [J. Phys. A 33, 4427 (2000)] to the case in which an ideal Fermi gas with an arbitrary number N of particles in a box trap is used as the working substance. Besides two quantum adiabatic processes, the engine model contains two isoenergetic processes, during which the particles are coupled to energy baths at a high constant energy E(h) and a low constant energy E(c), respectively. Directly employing the finite-time thermodynamics, we find that the power output is enhanced by increasing particle number N (or decreasing minimum trap size L(A)) for given L(A) (or N), without reduction in the efficiency. By use of global optimization, the efficiency at possible maximum power output (EPMP) is found to be universal and independent of any parameter contained in the engine model. For an engine model with any particle-number N, the efficiency at maximum power output (EMP) can be determined under the condition that it should be closest to the EPMP. Moreover, we extend the heat engine to a more general multilevel engine model with an arbitrary 1D power-law potential. Comparison between our engine model and the Carnot cycle shows that, under the same conditions, the efficiency η = 1 - E(c)/E(h) of the engine cycle is bounded from above the Carnot value η(c) =1 - T(c)/T(h). PMID:23005748

  15. Amine bearing polymeric particles as acid neutralizers for engine oils

    SciTech Connect

    Theodore, A.N.; Chattha, M.S.

    1986-02-04

    This patent describes a lubricating oil composition consisting of a major proportion of a lubricating base oil and about 0.1 to 15 weight percent of an acid neutralizing additive which consists of polymer particles (a) bearing pendant amine groups, and (b) having a diameter of about 500 A and 10,000 A. The amine functional particles are formed by reacting polymer particles bearing pendant epoxide groups with a secondary amine in an amount so as to react essentially all of the epoxide groups on the epoxide bearing polymer particles with the secondary amine. The polymer particles bearing pendant epoxide groups are formed by the free radical addition polymerization of: (a) between about 50 and about 100 weight percent of an ethylenically unsaturated monomers bearing an epoxide group, and (b) 0 up to about 50 weight percent of other monoethylenically unsaturated monomers; in the presence of: (I) a non-polar organic liquid which is a solvent for the polymerizable monomers, but a non-solvent for the resultant polymer, and (II) polymeric dispersion stabilizer containing at least two segments, with one segment being solvated by the non-polar organic liquid and the second segment being of different polarity than the first segment and relatively insoluble in the non-polar organic liquid. The second segment of the stabilizer is chemically attached to the polymerized particle.

  16. Sampling and analysis of aircraft engine cold start particles and demonstration of an electrostatic personal particle sampler.

    PubMed

    Armendariz, Alfredo; Leith, David; Boundy, Maryanne; Goodman, Randall; Smith, Les; Carlton, Gary

    2003-01-01

    Aircraft engines emit an aerosol plume during startup in extremely cold weather that can drift into areas occupied by flightline ground crews. This study tested a personal sampler used to assess exposure to particles in the plume under challenging field conditions. Area and personal samples were taken at two U.S. Air Force (USAF) flightlines during the winter months. Small tube-and-wire electrostatic precipitators (ESPs) were mounted on a stationary stand positioned behind the engines to sample the exhaust. Other ESPs were worn by ground crews to sample breathing zone concentrations. In addition, an aerodynamic particle sizer 3320 (APS) was used to determine the size distribution of the particles. Samples collected with the ESP were solvent extracted and analyzed with gas chromatography-mass spectrometry. Results indicated that the plume consisted of up to 75 mg/m(3) of unburned jet fuel particles. The APS showed that nearly the entire particle mass was respirable, because the plumes had mass median diameters less than 2 micro m. These tests demonstrated that the ESP could be used at cold USAF flightlines to perform exposure assessments to the cold start particles. PMID:14674797

  17. Performance Evaluation of Particle Sampling Probes for Emission Measurements of Aircraft Jet Engines

    NASA Technical Reports Server (NTRS)

    Lee, Poshin; Chen, Da-Ren; Sanders, Terry (Technical Monitor)

    2001-01-01

    Considerable attention has been recently received on the impact of aircraft-produced aerosols upon the global climate. Sampling particles directly from jet engines has been performed by different research groups in the U.S. and Europe. However, a large variation has been observed among published data on the conversion efficiency and emission indexes of jet engines. The variation results surely from the differences in test engine types, engine operation conditions, and environmental conditions. The other factor that could result in the observed variation is the performance of sampling probes used. Unfortunately, it is often neglected in the jet engine community. Particle losses during the sampling, transport, and dilution processes are often not discussed/considered in literatures. To address this issue, we evaluated the performance of one sampling probe by challenging it with monodisperse particles. A significant performance difference was observed on the sampling probe evaluated under different temperature conditions. Thermophoretic effect, nonisokinetic sampling and turbulence loss contribute to the loss of particles in sampling probes. The results of this study show that particle loss can be dramatic if the sampling probe is not well designed. Further, the result allows ones to recover the actual size distributions emitted from jet engines.

  18. REVIEW ARTICLE: Magnetostrictive delay lines: engineering theory and sensing applications

    NASA Astrophysics Data System (ADS)

    Hristoforou, E.

    2003-02-01

    A review of the engineering theory and the sensing element applications of the magnetostrictive delay line (MDL) technique is presented. The state of the art of magnetic materials and effects used in sensor design is overviewed and the operation of MDLs and their basic engineering properties are discussed. The resulting position, stress and field sensors based on this technique as well as their most significant applications are demonstrated. Finally, the industrialization process and the integration of the sensors with electronic circuitry as well as their evaluation with respect to the state of the art are discussed.

  19. Review of lattice results concerning low-energy particle physics

    SciTech Connect

    Aoki, S.; Aoki, Y.; Bernard, C.; Blum, T.; Colangelo, G.; Della Morte, M.; Dürr, S.; El-Khadra, A. X.; Fukaya, H.; Horsley, R.; Jüttner, A.; Kaneko, T.; Laiho, J.; Lellouch, L.; Leutwyler, H.; Lubicz, V.; Lunghi, E.; Necco, S.; Onogi, T.; Pena, C.; Sachrajda, C. T.; Sharpe, S. R.; Simula, S.; Sommer, R.; Van de Water, R. S.; Vladikas, A.; Wenger, U.; Wittig, H.

    2014-09-01

    We review lattice results related to pion, kaon, D- and B-meson physics with the aim of making them easily accessible to the particle physics community. More specifically, we report on the determination of the light-quark masses, the form factor f+(0), arising in semileptonic K -> pi transition at zero momentum transfer, as well as the decay constant ratio fK/fpi of decay constants and its consequences for the CKM matrix elements Vus and Vud. Furthermore, we describe the results obtained on the lattice for some of the low-energy constants of SU(2)LxSU(2)R and SU(3)LxSU(3)R Chiral Perturbation Theory and review the determination of the BK parameter of neutral kaon mixing. The inclusion of heavy-quark quantities significantly expands the FLAG scope with respect to the previous review. Therefore, for this review, we focus on D- and B-meson decay constants, form factors, and mixing parameters, since these are most relevant for the determination of CKM matrix elements and the global CKM unitarity-triangle fit. In addition we review the status of lattice determinations of the strong coupling constant alpha_s.

  20. Review of lattice results concerning low-energy particle physics

    DOE PAGESBeta

    Aoki, S.; Aoki, Y.; Bernard, C.; Blum, T.; Colangelo, G.; Della Morte, M.; Dürr, S.; El-Khadra, A. X.; Fukaya, H.; Horsley, R.; et al

    2014-09-01

    We review lattice results related to pion, kaon, D- and B-meson physics with the aim of making them easily accessible to the particle physics community. More specifically, we report on the determination of the light-quark masses, the form factor f+(0), arising in semileptonic K -> pi transition at zero momentum transfer, as well as the decay constant ratio fK/fpi of decay constants and its consequences for the CKM matrix elements Vus and Vud. Furthermore, we describe the results obtained on the lattice for some of the low-energy constants of SU(2)LxSU(2)R and SU(3)LxSU(3)R Chiral Perturbation Theory and review the determination ofmore » the BK parameter of neutral kaon mixing. The inclusion of heavy-quark quantities significantly expands the FLAG scope with respect to the previous review. Therefore, for this review, we focus on D- and B-meson decay constants, form factors, and mixing parameters, since these are most relevant for the determination of CKM matrix elements and the global CKM unitarity-triangle fit. In addition we review the status of lattice determinations of the strong coupling constant alpha_s.« less

  1. Nuclear and particle physics, astrophysics and cosmology (NPAC) capability review

    SciTech Connect

    Redondo, Antonio

    2010-01-01

    The present document represents a summary self-assessment of the status of the Nuclear and Particle Physics, Astrophysics and Cosmology (NPAC) capability across Los Alamos National Laboratory (LANL). For the purpose of this review, we have divided the capability into four theme areas: Nuclear Physics, Particle Physics, Astrophysics and Cosmology, and Applied Physics. For each theme area we have given a general but brief description of the activities under the area, a list of the Laboratory divisions involved in the work, connections to the goals and mission of the Laboratory, a brief description of progress over the last three years, our opinion of the overall status of the theme area, and challenges and issues.

  2. Emissions of submicron particles from a direct injection diesel engine by using biodiesel.

    PubMed

    Chen, Yen-Cho; Wu, Chung-Hsing

    2002-01-01

    Small airborne particles less than 1 microm in diameter have a high probability to deposit deeply in the respiratory tract and cause respiratory diseases such as lung cancer. In this study, emission characteristics of submicron particles from a direct injection diesel engine using biodiesel (provided by the American Soybean Association) and petroleum-diesel fuels were measured under different operation conditions. The results show that the emitted particle sizes for both fuels are about the same. But when fueled with biodiesel, the diesel engine can substantially reduce 24-42% emission of the total number concentration, and 40-49% of the total mass concentration of submicron particles, which indicates that the emission of submicron particles can be effectively approved. PMID:12049119

  3. Properties of jet engine combustion particles during the PartEmis experiment: Microphysics and Chemistry

    NASA Astrophysics Data System (ADS)

    Petzold, A.; Stein, C.; Nyeki, S.; Gysel, M.; Weingartner, E.; Baltensperger, U.; Giebl, H.; Hitzenberger, R.; Döpelheuer, A.; Vrchoticky, S.; Puxbaum, H.; Johnson, M.; Hurley, C. D.; Marsh, R.; Wilson, C. W.

    2003-07-01

    The particles emitted from an aircraft engine combustor were investigated in the European project PartEmis. Measured aerosol properties were mass and number concentration, size distribution, mixing state, thermal stability of internally mixed particles, hygroscopicity, and cloud condensation nuclei (CCN) activation potential. The combustor operation conditions corresponded to modern and older engine gas path temperatures at cruise altitude, with fuel sulphur contents (FSC) of 50, 410, and 1270 μg g-1. Operation conditions and FSC showed only a weak influence on the microphysical aerosol properties, except for hygroscopic and CCN properties. Particles of size D >= 30 nm were almost entirely internally mixed. Particles of sizes D < 20 nm showed a considerable volume fraction of compounds that volatilise at 390 K (10-15%) and 573 K (4-10%), while respective fractions decreased to <5% for particles of size D >= 50 nm.

  4. Particle emissions, volatility, and toxicity from an ethanol fumigated compression ignition engine.

    PubMed

    Surawski, Nicholas C; Miljevic, Branka; Roberts, Boyd A; Modini, Robin L; Situ, Rong; Brown, Richard J; Bottle, Steven E; Ristovski, Zoran D

    2010-01-01

    Particle emissions, volatility, and the concentration of reactive oxygen species (ROS) were investigated for a pre-Euro I compression ignition engine to study the potential health impacts of employing ethanol fumigation technology. Engine testing was performed in two separate experimental campaigns with most testing performed at intermediate speed with four different load settings and various ethanol substitutions. A scanning mobility particle sizer (SMPS) was used to determine particle size distributions, a volatilization tandem differential mobility analyzer (V-TDMA) was used to explore particle volatility, and a new profluorescent nitroxide probe, BPEAnit, was used to investigate the potential toxicity of particles. The greatest particulate mass reduction was achieved with ethanol fumigation at full load, which contributed to the formation of a nucleation mode. Ethanol fumigation increased the volatility of particles by coating the particles with organic material or by making extra organic material available as an external mixture. In addition, the particle-related ROS concentrations increased with ethanol fumigation and were associated with the formation of a nucleation mode. The smaller particles, the increased volatility, and the increase in potential particle toxicity with ethanol fumigation may provide a substantial barrier for the uptake of fumigation technology using ethanol as a supplementary fuel. PMID:19994903

  5. Transport and Retention of Engineered Nanoporous Particles in Porous Media: Effects of Concentration and Flow Dynamics

    SciTech Connect

    Shang, Jianying; Liu, Chongxuan; Wang, Zheming

    2013-01-20

    Engineered nanoporous particles are an important class of nano-structured materials that can be functionalized in their internal surfaces for various applications including groundwater contaminant sequestration. This paper reported a study of transport and retention of engineered nanoporous silicate particles (ENSPs) that are designed for treatment and remediation of contaminants such as uranium in groundwater and sediments. The transport and retention of ENSPs were investigated under variable particle concentrations and dynamic flow conditions in a synthetic groundwater that mimics field groundwater chemical composition. The dynamic flow condition was achieved using a flow-interruption (stop-flow) approach with variable stop-flow durations to explore particle retention and release kinetics. The results showed that the ENSPs transport was strongly affected by the particle concentrations and dynamic flow conditions. A lower injected ENSPs concentration and longer stop-flow duration led to a more particle retention. The experimental data were used to evaluate the applicability of various kinetic models that were developed for colloidal particle retention and release in describing ENSPs transport. Model fits suggested that the transport and retention of ENSPs were subjected to a complex coupling of reversible attachment/detachment and straining/liberation processes. Both experimental and modeling results indicated that dynamic groundwater flow condition is an important parameter to be considered in exploring and modeling engineered particle transport in subsurface porous media.

  6. A source-independent empirical correction procedure for the fast mobility and engine exhaust particle sizers

    NASA Astrophysics Data System (ADS)

    Zimmerman, Naomi; Jeong, Cheol-Heon; Wang, Jonathan M.; Ramos, Manuel; Wallace, James S.; Evans, Greg J.

    2015-01-01

    The TSI Fast Mobility Particle Sizer (FMPS) and Engine Exhaust Particle Sizer (EEPS) provide size distributions for 6-560 nm particles with a time resolution suitable for characterizing transient particle sources; however, the accuracy of these instruments can be source dependent, due to influences of particle morphology. The aim of this study was to develop a source-independent correction protocol for the FMPS and EEPS. The correction protocol consists of: (1) broadening the >80 nm size range of the distribution to account for under-sizing by the FMPS and EEPS; (2) applying an existing correction protocol in the 8-93 nm size range; and (3) dividing each size bin by the ratio of total concentration measured by the FMPS or EEPS and a water-based Condensation Particle Counter (CPC) as a surrogate scaling factor to account for particle morphology. Efficacy of the correction protocol was assessed for three sources: urban ambient air, diluted gasoline direct injection engine exhaust, and diluted diesel engine exhaust. Linear regression against a reference instrument, the Scanning Mobility Particle Sizer (SMPS), before and after applying the correction protocol demonstrated that the correction ensured agreement within 20%.

  7. Brief review of uncertainty quantification for particle image velocimetry

    NASA Astrophysics Data System (ADS)

    Farias, M. H.; Teixeira, R. S.; Koiller, J.; Santos, A. M.

    2016-07-01

    Metrological studies for particle image velocimetry (PIV) are recent in literature. An attempt to evaluate the uncertainty quantifications (UQ) of the PIV velocity field are in evidence. Therefore, a short review on main sources of uncertainty in PIV and available methodologies for its quantification are presented. In addition, the potential of some mathematical techniques, coming from the area of geometric mechanics and control, that could interest the fluids UQ community are highlighted as good possibilities. “We must measure what is measurable and make measurable what cannot be measured” (Galileo)

  8. A Review of Three-Dimensional Printing in Tissue Engineering.

    PubMed

    Sears, Nick A; Seshadri, Dhruv R; Dhavalikar, Prachi S; Cosgriff-Hernandez, Elizabeth

    2016-08-01

    Recent advances in three-dimensional (3D) printing technologies have led to a rapid expansion of applications from the creation of anatomical training models for complex surgical procedures to the printing of tissue engineering constructs. In addition to achieving the macroscale geometry of organs and tissues, a print layer thickness as small as 20 μm allows for reproduction of the microarchitectures of bone and other tissues. Techniques with even higher precision are currently being investigated to enable reproduction of smaller tissue features such as hepatic lobules. Current research in tissue engineering focuses on the development of compatible methods (printers) and materials (bioinks) that are capable of producing biomimetic scaffolds. In this review, an overview of current 3D printing techniques used in tissue engineering is provided with an emphasis on the printing mechanism and the resultant scaffold characteristics. Current practical challenges and technical limitations are emphasized and future trends of bioprinting are discussed. PMID:26857350

  9. Synthetic biodegradable functional polymers for tissue engineering: a brief review

    PubMed Central

    BaoLin, GUO; MA, Peter X.

    2015-01-01

    Scaffolds play a crucial role in tissue engineering. Biodegradable polymers with great processing flexibility are the predominant scaffolding materials. Synthetic biodegradable polymers with well-defined structure and without immunological concerns associated with naturally derived polymers are widely used in tissue engineering. The synthetic biodegradable polymers that are widely used in tissue engineering, including polyesters, polyanhydrides, polyphosphazenes, polyurethane, and poly (glycerol sebacate) are summarized in this article. New developments in conducting polymers, photoresponsive polymers, amino-acid-based polymers, enzymatically degradable polymers, and peptide-activated polymers are also discussed. In addition to chemical functionalization, the scaffold designs that mimic the nano and micro features of the extracellular matrix (ECM) are presented as well, and composite and nanocomposite scaffolds are also reviewed. PMID:25729390

  10. Sandia Computational Engine for Particle Transport for Radiation Effects.

    Energy Science and Technology Software Center (ESTSC)

    2014-09-01

    Version 00 The SCEPTRE code solves the linear Boltzmann transport equation for one-, two- and three-dimensional geometries. SCEPTRE is capable of handling any particle type for which multigroup-Legendre cross sections are available. However, the code is designed primarily to model the transport of photons, electrons, and positrons through matter. For efficiency and flexibility, SCEPTRE contains capability for both the first- and second-order forms of the Boltzmann transport equation.

  11. ENGINEERING NANO- AND MICRO-PARTICLES TO TUNE IMMUNITY

    PubMed Central

    Moon, James J.; Irvine, Darrell J.; Huang, Bonnie

    2013-01-01

    The immune system can be a cure or cause of disease, fulfilling a protective role in attacking cancer or pathogenic microbes but also causing tissue destruction in autoimmune disorders. Thus, therapies aimed to amplify or suppress immune reactions are of great interest. However, the complex regulation of the immune system, coupled with the potential systemic side effects associated with traditional systemic drug therapies, has presented a major hurdle for the development of successful immunotherapies,. Recent progress in the design of synthetic micro- and nano-particles that can target drugs, deliver imaging agents, or stimulate immune cells directly through their physical and chemical properties is leading to new approaches to deliver vaccines, promote immune responses against tumors, and suppress autoimmunity. In addition, novel strategies, such as the use of particle-laden immune cells as living targeting agents for drugs, are providing exciting new approaches for immunotherapy. This progress report describes recent advances in the design of micro- and nano-particles in immunotherapies and diagnostics. PMID:22641380

  12. Problems and outlooks for petrothermal power engineering ( review)

    NASA Astrophysics Data System (ADS)

    Alekseenko, S. V.; Borodulin, V. Yu.; Gnatus, N. A.; Nizovtsev, M. I.; Smirnova, N. N.

    2016-01-01

    A review is given for the state of the art and future development of the geothermal power engineering. Different diagrams of GeoPP are shown for different levels of geofluid temperature. A special focus is made on challenges for petrothermal power production. The huge amount of heat from petrothermal resources can be harnessed through creating geothermal circulation systems within the dry rocks. Estimates for system lifetime and heat production capacity of circulation systems are given for different flow rates of coolant.

  13. Soot particle size modelling in 3D simulations of diesel engine combustion

    NASA Astrophysics Data System (ADS)

    Fraioli, V.; Beatrice, C.; Lazzaro, M.

    2011-12-01

    The present work is focused on multi-dimensional simulations of combustion in diesel engines. The primary objective was to test, in a diesel engine framework, a soot particle size model to represent the carbon particle formation and calculate the corresponding size distribution function. Simulations are performed by means of a parallel version of the KIVA3V numerical code, modified to adopt detailed kinetics reaction mechanisms. A skeletal reaction scheme for n-heptane autoignition has been extended, to include PAH kinetics and carbonaceous particle formation and consumption rates: the full reaction set is made up of 82 gas species and 50 species accounting for the particles, thus the complete reaction scheme comprises 132 species and 2206 reaction steps. Four different engine operative conditions, varying engine speed and load, are taken into account and experimentally tested on a single cylinder diesel engine fuelling pure n-heptane. Computed particle size distribution functions are compared with corresponding measurements at the exhaust, performed by a differential mobility spectrometer. A satisfying agreement between computed and measured combustion profiles is obtained in all the conditions. A reasonable aerosol evolution can be obtained, yet in all the cases the model exhibits the tendency to overestimate the number of particles within the range 5-160 nm. Moreover calculations predict a nucleation mode not detected by the available instrument. According to the simulations, the total number and size of the nascent particles would not depend on the operative conditions, while the features of the larger aggregates distinctly vary with the engine functioning.

  14. Soot particle trajectories of a Di diesel engine at 18° ATDC crankshaft angle

    NASA Astrophysics Data System (ADS)

    Hafidzal, M. H. M.; Mahmood, W. M. F. W.; Manaf, M. Z. A.; Zakaria, M. S.; Saadun, M. N. A.; Nordin, M. N. A.

    2013-12-01

    Among the major pollutants of diesel engine is soot. Soot is formed as an unwelcome product in combustion systems. Soot emission to the atmosphere leads to global air warming and health problems. Furthermore, deposition of soot particles on cylinder walls contaminates lubricant oil hence increases its viscosity. This reduces durability of lubricant oil, causing pumpability problems and increasing wear. Therefore, it is necessary to study soot formation and its movement in diesel engines. This study focuses on soot particle trajectories in diesel engines by considering the diameter of soot particles that were formed at 18° ATDC crankshaft angle. These soot particle movements are under the influence of drag force with different radial, axial and angular settings and simulated by using MATLAB routine. The mathematical algorithm which was used in the MATLAB routine is trilinear interpolation and 4th order of Runge Kutta. Simulation was carried out for a combustion system of 4 valves DI diesel engine from inlet valve closing (IVC) to exhaust valve opening (EVO). The results show that small diameter of soot particles were transferred near the cylinder wall while bigger soot particle mostly moved in inner radius of the combustion chamber.

  15. 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.

  16. Particle engineering using sonocrystallization: salbutamol sulphate for pulmonary delivery.

    PubMed

    Dhumal, Ravindra S; Biradar, Shailesh V; Paradkar, Anant R; York, Peter

    2009-02-23

    The aim of present work was to produce fine elongated crystals of salbutamol sulphate (SS) by sonocrystallization for pulmonary delivery and compare with micronized and spray dried SS (SDSS) for in vitro aerosolization behavior. Application of ultrasound during anti-solvent crystallization resulted in fine elongated crystals (sonocrystallized SS; SCSS) compared to aggregates of large irregular crystals obtained without sonication. Higher sonication amplitude, time, concentration and lower processing temperatures favored formation of smaller crystals with narrow particle size distribution (PSD). SCSS was separated from dispersion by spray drying in the form of loose aggregates (SD-SCSS). The fine particle fraction (FPF) of formulations with coarse lactose carrier in cascade impactor increased from 16.66% for micronized SS to 31.12% for SDSS (obtained by spray drying aqueous SS solution) and 44.21% for SD-SCSS, due to reduced cohesive/adhesive forces and aerodynamic size by virtue of elongated shape of crystals. SD-SCSS was stable without any change in crystallinity and aerodynamic behavior for 3 months at 40 degrees C/75% RH, but amorphous SDSS showed recrystallization with poor aerosolization performance on storage. Sonocrystallization, a rapid and simple technique is reported for production of SS crystals suitable for inhalation delivery. PMID:18996462

  17. A RECIPROCATING SOLAR HEATED ENGINE UTILIZING DIRECT ABSORPTION BY SMALL PARTICLES

    SciTech Connect

    Hull, Patricia G.; Hunt, Arlon J.

    1981-05-01

    A new type of reciprocating solar engine utilizing small particles to absorb concentrated sunlight directly within the cylinders is described. The engine operates by drawing an air particle mixture into the cylinder, compressing the mixture, opening an optical valve to allow concentrated sunlight to enter through a window in the top of the cylinder head, absorbing the solar flux with the particles, and converting the heat trapped by the air-particle mixture into mechanical energy with the downward stroke of piston. It differs from other gas driven heat engines using solar energy in three main respects. First, the radiant flux is deposited directly in the working fluid inside the cylinder; second, the heat is directed to the appropriate cylinder by controlling the solar flux by an optical system; third, the gas is heated during a significant portion of the compression stroke. The thermodynamic efficiency of the engine is calculated using an analytical model and is compared to several other engine cycles of interest.

  18. Engineered plant biomass particles coated with biological agents

    DOEpatents

    Dooley, James H.; Lanning, David N.

    2014-06-24

    Plant biomass particles coated with a biological agent such as a bacterium or seed, characterized by a length dimension (L) aligned substantially parallel to a grain direction and defining a substantially uniform distance along the grain, a width dimension (W) normal to L and aligned cross grain, and a height dimension (H) normal to W and L. In particular, the L.times.H dimensions define a pair of substantially parallel side surfaces characterized by substantially intact longitudinally arrayed fibers, the W.times.H dimensions define a pair of substantially parallel end surfaces characterized by crosscut fibers and end checking between fibers, and the L.times.W dimensions define a pair of substantially parallel top and bottom surfaces.

  19. Engineered plant biomass particles coated with bioactive agents

    SciTech Connect

    Dooley, James H; Lanning, David N

    2013-07-30

    Plant biomass particles coated with a bioactive agent such as a fertilizer or pesticide, characterized by a length dimension (L) aligned substantially parallel to a grain direction and defining a substantially uniform distance along the grain, a width dimension (W) normal to L and aligned cross grain, and a height dimension (H) normal to W and L. In particular, the L.times.H dimensions define a pair of substantially parallel side surfaces characterized by substantially intact longitudinally arrayed fibers, the W.times.H dimensions define a pair of substantially parallel end surfaces characterized by crosscut fibers and end checking between fibers, and the L.times.W dimensions define a pair of substantially parallel top and bottom surfaces.

  20. Quantum-Carnot engine for particle confined to cubic potential

    SciTech Connect

    Sutantyo, Trengginas Eka P. Belfaqih, Idrus H. Prayitno, T. B.

    2015-09-30

    Carnot cycle consists of isothermal and adiabatic processes which are reversible. Using analogy in quantum mechanics, these processes can be well explained by replacing variables in classical process with a quantum system. Quantum system which is shown in this paper is a particle that moves under the influence of a cubic potential which is restricted only to the state of the two energy levels. At the end, the efficiency of the system is shown as a function of the width ratio between the initial conditions and the farthest wall while expanding. Furthermore, the system efficiency will be considered 1D and 2D cases. The providing efficiencies are different due to the influence of the degeneration of energy and the degrees of freedom of the system.

  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. PMID:18982535

  2. Laser Surface Engineering of Magnesium Alloys: A Review

    NASA Astrophysics Data System (ADS)

    Singh, Ashish; Harimkar, Sandip P.

    2012-06-01

    Magnesium (Mg) and its alloys are well known for their high specific strength and low density. However, widespread applications of Mg alloys in structural components are impeded by their insufficient wear and corrosion resistance. Various surface engineering approaches, including electrochemical processes (plating, conversion coatings, hydriding, and anodizing), gas-phase deposition (thermal spray, chemical vapor deposition, physical vapor deposition, diamond-like coatings, diffusion coatings, and ion implantation), and organic polymer coatings (painting and powder coating), have been used to improve the surface properties of Mg and its alloys. Recently, laser surface engineering approaches are attracting significant attention because of the wide range of possibilities in achieving the desired microstructural and compositional modifications through a range of laser-material interactions (surface melting, shock peening, and ablation). This article presents a review of various laser surface engineering approaches such as laser surface melting, laser surface alloying, laser surface cladding, laser composite surfacing, and laser shock peening used for surface modification of Mg alloys. The laser-material interactions, microstructural/compositional changes, and properties development (mostly corrosion and wear resistance) accompanied with each of these approaches are reviewed.

  3. Transparent exopolymer particles: from aquatic environments and engineered systems to membrane biofouling.

    PubMed

    Bar-Zeev, Edo; Passow, Uta; Castrillón, Santiago Romero-Vargas; Elimelech, Menachem

    2015-01-20

    Transparent exopolymer particles (TEP) are ubiquitous in marine and freshwater environments. For the past two decades, the distribution and ecological roles of these polysaccharide microgels in aquatic systems were extensively investigated. More recent studies have implicated TEP as an active agent in biofilm formation and membrane fouling. Since biofouling is one of the main hurdles for efficient operation of membrane-based technologies, there is a heightened interest in understanding the role of TEP in engineered water systems. In this review, we describe relevant TEP terminologies while critically discussing TEP biological origin, biochemical and physical characteristics, and occurrence and distributions in aquatic systems. Moreover, we examine the contribution of TEP to biofouling of various membrane technologies used in the desalination and water/wastewater treatment industry. Emphasis is given to the link between TEP physicochemical and biological properties and the underlying biofouling mechanisms. We highlight that thorough understanding of TEP dynamics in feedwater sources, pretreatment challenges, and biofouling mechanisms will lead to better management of fouling/biofouling in membrane technologies. PMID:25494664

  4. 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. PMID:26446468

  5. SENSITIZATION AND EXACERBATION OF ALLERGIC DISEASES BY DIESEL ENGINE PARTICLES

    SciTech Connect

    Diaz-Sanchez, David

    2000-08-20

    Most studies of the health effects of diesel exhaust have focused on the controversial issue of its role in cancer. However, recently the role of combustion products such as diesel exhaust particles (DEP) in modulating the immune response has garnered much attention. In particular the effect of DEP on allergic and asthmatic diseases has been the focus of many studies. A link between industrialization and allergic disease has long been presumed. Indeed, only 50 years after the first recorded reported case of allergy in 1819, Charles Blackely wrote that the ''hay-fever epidemic'' was associated with the movement of people from the country into the cities. Ishizaki et al. (1987) found that people in Japan living on busy roads lined with cedar trees have more allergies to cedar than residents living on similar streets with much less traffic. Since that time other epidemiological studies have reported similar findings. Kramer, et al., showed that hay fever is greater in residential areas with heavy truck traffic, while Weiland, et al., reported that allergic symptoms correlate with the distance of residences to roads with heavy traffic.

  6. Jet Engine Powerloss in Ice Particle Conditions: An Aviation Industry Problem

    NASA Astrophysics Data System (ADS)

    Strapp, J. W.

    2009-09-01

    Since about the 1990, there have been in excess of 100 engine powerloss events in jet aircraft that have now been attributed to the ingestion of ice particles. These powerloss events are observed in essentially all engine types, and on all airframes. Almost all cases have occurred in the vicinity of deep convection usually associated with warm and moist atmospheres. Events have occurred all throughout the world, although there is a somewhat higher concentration in the area of southeast Asia. Powerloss can result from stall, surge, flameout and rollback events in the engine. Many are momentary, with engines relighting automatically, while others require a manual engine relight. In some cases, particularly in rollback cases on smaller commuter-transport aircraft, engine power has only been recovered by melting of ice buildup in the engine below the freezing level. There have been cases of multiple simultaneous engine powerloss, and one case of a landing with no engine power. The frequency of the events, and the potential for multiple-engine powerloss, has led the FAA to note that that these occurrences constitute a significant safety issue. Analysis of the events using aircraft flight data recorder information, pilot interviews, standard meteorological radar and satellite data, and information from several past flight test programs, have led to the conclusion that the powerloss is due to ice buildup in the engine from high concentrations of ice particles in the atmosphere, and that supercooled LWC is not required. This is an unconventional form of icing that had not been previously considered possible by engine designers. The Engine Harmonization Working Group (EHWG), an industry-led committee composed of engine manufacturers, airframe manufacturers, regulators, and government agencies have been studying the powerloss issue since 2004, and have suggested a 4-part technical plan to resolve the issue, which includes improvement of instrumentation to measure high ice

  7. 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

  8. Abrasive wear by coal-fueled diesel engine and related particles

    SciTech Connect

    Ives, L.K.

    1992-09-01

    The development of commercially viable diesel engines that operate directly on pulverized coal-fuels will require solution to the problem of severe abrasive wear. The purpose of the work described in this report was to investigate the nature of the abrasive wear problem. Analytical studies were carried out to determine the characteristics of the coal-fuel and associated combustion particles responsible for abrasion. Laboratory pinon-disk wear tests were conducted on oil-particle mixtures to determine the relationship between wear rate and a number of different particle characteristics, contact parameters, specimen materials properties, and other relevant variables.

  9. Digital particle image thermometry/velocimetry: a review

    NASA Astrophysics Data System (ADS)

    Dabiri, Dana

    2009-02-01

    Digital particle image thermometry/velocimetry (DPIT/V) is a relatively new methodology that allows for measurements of simultaneous temperature and velocity within a two-dimensional domain, using thermochromic liquid crystal tracer particles as the temperature and velocity sensors. Extensive research has been carried out over recent years that have allowed the methodology and its implementation to grow and evolve. While there have been several reviews on the topic of liquid crystal thermometry (Moffat in Exp Therm Fluid Sci 3:14-32, 1990; Baughn in Int J Heat Fluid Flow 16:365-375, 1995; Roberts and East in J Spacecr Rockets 33:761-768, 1996; Wozniak et al. in Appl Sci Res 56:145-156, 1996; Behle et al. in Appl Sci Res 56:113-143, 1996; Stasiek in Heat Mass Transf 33:27-39, 1997; Stasiek and Kowalewski in Opto Electron Rev 10:1-10, 2002; Stasiek et al. in Opt Laser Technol 38:243-256, 2006; Smith et al. in Exp Fluids 30:190-201, 2001; Kowalewski et al. in Springer handbook of experimental fluid mechanics, 1st edn. Springer, Berlin, pp 487-561, 2007), the focus of the present review is to provide a relevant discussion of liquid crystals pertinent to DPIT/V. This includes a background on liquid crystals and color theory, a discussion of experimental setup parameters, a description of the methodology’s most recent advances and processing methods affecting temperature measurements, and finally an explanation of its various implementations and applications.

  10. Automotive Stirling Engine Mod 1 Design Review, Volume 1

    NASA Technical Reports Server (NTRS)

    1982-01-01

    Risk assessment, safety analysis of the automotive stirling engine (ASE) mod I, design criteria and materials properties for the ASE mod I and reference engines, combustion are flower development, and the mod I engine starter motor are discussed. The stirling engine system, external heat system, hot engine system, cold engine system, and engine drive system are also discussed.

  11. Environmental behavior of engineered nanomaterials in porous media: a review.

    PubMed

    Park, Chang Min; Chu, Kyoung Hoon; Heo, Jiyong; Her, Namguk; Jang, Min; Son, Ahjeong; Yoon, Yeomin

    2016-05-15

    A pronounced increase in the use of nanotechnology has resulted in nanomaterials being released into the environment. Environmental exposure to the most common engineered nanomaterials (ENMs), such as carbon-based and metal-based nanomaterials, can occur directly via intentional injection for remediation purposes, release during the use of nanomaterial-containing consumer goods, or indirectly via different routes. Recent reviews have outlined potential risks assessments, toxicity, and life cycle analyses regarding ENM emission. In this review, inevitable release of ENMs and their environmental behaviors in aqueous porous media are discussed with an emphasis on influencing factors, including the physicochemical properties of ENMs, solution chemistry, soil hydraulic properties, and soil matrices. Major findings of laboratory column studies and numerical approaches for the transport of ENMs are addressed, and studies on the interaction between ENMs and heavy metal ions in aqueous soil environments are examined. Future research is also presented with specific research directions and outlooks. PMID:26882524

  12. 2014 Space Human Factors Engineering Standing Review Panel

    NASA Technical Reports Server (NTRS)

    Steinberg, Susan

    2014-01-01

    The 2014 Space Human Factors Engineering (SHFE) Standing Review Panel (from here on referred to as the SRP) participated in a WebEx/teleconference with members of the Space Human Factors and Habitability (SHFH) Element, representatives from the Human Research Program (HRP), the National Space Biomedical Research Institute (NSBRI), and NASA Headquarters on November 17, 2014 (list of participants is in Section XI of this report). The SRP reviewed the updated research plans for the Risk of Incompatible Vehicle/Habitat Design (HAB Risk) and the Risk of Performance Errors Due to Training Deficiencies (Train Risk). The SRP also received a status update on the Risk of Inadequate Critical Task Design (Task Risk), the Risk of Inadequate Design of Human and Automation/Robotic Integration (HARI Risk), and the Risk of Inadequate Human-Computer Interaction (HCI Risk).

  13. A personal sampler for aircraft engine cold start particles: laboratory development and testing.

    PubMed

    Armendariz, Alfredo; Leith, David

    2003-01-01

    Industrial hygienists in the U.S. Air Force are concerned about exposure of their personnel to jet fuel. One potential source of exposure for flightline ground crews is the plume emitted during the start of aircraft engines in extremely cold weather. The purpose of this study was to investigate a personal sampler, a small tube-and-wire electrostatic precipitator (ESP), for assessing exposure to aircraft engine cold start particles. Tests were performed in the laboratory to characterize the sampler's collection efficiency and to determine the magnitude of adsorption and evaporation artifacts. A low-temperature chamber was developed for the artifact experiments so tests could be performed at temperatures similar to actual field conditions. The ESP collected particles from 0.5 to 20 micro m diameter with greater than 98% efficiency at particle concentrations up to 100 mg/m(3). Adsorption artifacts were less than 5 micro g/m(3) when sampling a high concentration vapor stream. Evaporation artifacts were significantly lower for the ESP than for PVC membrane filters across a range of sampling times and incoming vapor concentrations. These tests indicate that the ESP provides more accurate exposure assessment results than traditional filter-based particle samplers when sampling cold start particles produced by an aircraft engine. PMID:14674798

  14. An Improved Effective Cost Review Process for Value Engineering

    PubMed Central

    Joo, D. S.; Park, J. I.

    2014-01-01

    Second-look value engineering (VE) is an approach that aims to lower the costs of products for which target costs are not being met during the production stage. Participants in second-look VE typically come up with a variety of ideas for cost cutting, but the outcomes often depend on their levels of experience, and not many good alternatives are available during the production stage. Nonetheless, good ideas have been consistently generated by VE experts. This paper investigates past second-look VE cases and the thinking processes of VE experts and proposes a cost review process as a systematic means of investigating cost-cutting ideas. This cost review process includes the use of an idea checklist and a specification review process. In addition to presenting the process, this paper reports on its feasibility, based on its introduction into a VE training course as part of a pilot study. The results indicate that the cost review process is effective in generating ideas for later analysis. PMID:25580459

  15. Characterization and mapping of very fine particles in an engine machining and assembly facility.

    PubMed

    Heitbrink, William A; Evans, Douglas E; Peters, Thomas M; Slavin, Thomas J

    2007-05-01

    Very fine particle number and mass concentrations were mapped in an engine machining and assembly facility in the winter and summer. A condensation particle counter (CPC) was used to measure particle number concentrations in the 0.01 microm to 1 microm range, and an optical particle counter (OPC) was used to measure particle number concentrations in 15 channels between 0.3 microm and 20 microm. The OPC measurements were used to estimate the respirable mass concentration. Very fine particle number concentrations were estimated by subtracting the OPC particle number concentrations from 0.3 microm to 1 microm from the CPC number concentrations. At specific locations during the summer visit, an electrical low pressure impactor was used to measure particle size distribution from 0.07 microm to 10 microm in 12 channels. The geometric mean ratio of respirable mass concentration estimated from the OPC to the gravimetrically measured mass concentration was 0.66 with a geometric standard deviation of 1.5. Very fine particle number concentrations in winter were substantially greater where direct-fire natural gas heaters were operated (7.5 x 10(5) particles/cm(3)) than where steam was used for heat (3 x 10(5) particles/cm(3)). During summer when heaters were off, the very fine particle number concentrations were below 10(5) particles/cm(3), regardless of location. Elevated very fine particle number concentrations were associated with machining operations with poor enclosures. Whereas respirable mass concentrations did not vary noticeably with season, they were greater in areas with poorly fitting enclosures (0.12 mg/m(3)) than in areas where state-of-the-art enclosures were used (0.03 mg/m(3)). These differences were attributed to metalworking fluid mist that escaped from poorly fitting enclosures. Particles generated from direct-fire natural gas heater operation were very small, with a number size distribution modal diameter of less than 0.023 microm. Aerosols generated by

  16. An Alternative Perspective for Malaysian Engineering Education: A Review from Year 2000-2012

    ERIC Educational Resources Information Center

    Jayarajah, Kamaleswaran; Saat, Rohaida Mohd; Rauf, Rose Amnah Abdul

    2013-01-01

    The purpose of this study is to explore the research base of engineering education in the "Journal of Engineering Education" ("JEE") through an analysis review of articles for a 12-year period, from 2000 to 2012. The research base review focuses on identifying five characteristics of engineering education: (a) temporal…

  17. Alginate composites for bone tissue engineering: a review.

    PubMed

    Venkatesan, Jayachandran; Bhatnagar, Ira; Manivasagan, Panchanathan; Kang, Kyong-Hwa; Kim, Se-Kwon

    2015-01-01

    Bone is a complex and hierarchical tissue consisting of nano hydroxyapatite and collagen as major portion. Several attempts have been made to prepare the artificial bone so as to replace the autograft and allograft treatment. Tissue engineering is a promising approach to solve the several issues and is also useful in the construction of artificial bone with materials including polymer, ceramics, metals, cells and growth factors. Composites consisting of polymer-ceramics, best mimic the natural functions of bone. Alginate, an anionic polymer owing enormous biomedical applications, is gaining importance particularly in bone tissue engineering due to its biocompatibility and gel forming properties. Several composites such as alginate-polymer (PLGA, PEG and chitosan), alginate-protein (collagen and gelatin), alginate-ceramic, alginate-bioglass, alginate-biosilica, alginate-bone morphogenetic protein-2 and RGD peptides composite have been investigated till date. These alginate composites show enhanced biochemical significance in terms of porosity, mechanical strength, cell adhesion, biocompatibility, cell proliferation, alkaline phosphatase increase, excellent mineralization and osteogenic differentiation. Hence, alginate based composite biomaterials will be promising for bone tissue regeneration. This review will provide a broad overview of alginate preparation and its applications towards bone tissue engineering. PMID:25020082

  18. Liquid-Propellant Rocket Engine Throttling: A Comprehensive Review

    NASA Technical Reports Server (NTRS)

    Casiano, Matthew; Hulka, James; Yang, Virog

    2009-01-01

    Liquid-Propellant Rocket Engines (LREs) are capable of on-command variable thrust or thrust modulation, an operability advantage that has been studied intermittently since the late 1930s. Throttleable LREs can be used for planetary entry and descent, space rendezvous, orbital maneuvering including orientation and stabilization in space, and hovering and hazard avoidance during planetary landing. Other applications have included control of aircraft rocket engines, limiting of vehicle acceleration or velocity using retrograde rockets, and ballistic missile defense trajectory control. Throttleable LREs can also continuously follow the most economical thrust curve in a given situation, compared to discrete throttling changes over a few select operating points. The effects of variable thrust on the mechanics and dynamics of an LRE as well as difficulties and issues surrounding the throttling process are important aspects of throttling behavior. This review provides a detailed survey of LRE throttling centered around engines from the United States. Several LRE throttling methods are discussed, including high-pressure-drop systems, dual-injector manifolds, gas injection, multiple chambers, pulse modulation, throat throttling, movable injector components, and hydrodynamically dissipative injectors. Concerns and issues surrounding each method are examined, and the advantages and shortcomings compared.

  19. Independent engineering review of the Hanford Waste Vitrification System

    SciTech Connect

    Not Available

    1991-10-01

    The Hanford Waste Vitrification Plant (HWVP) was initiated in June 1987. The HWVP is an essential element of the plan to end present interim storage practices for defense wastes and to provide for permanent disposal. The project start was justified, in part, on efficient technology and design information transfer from the prototype Defense Waste Processing Facility (DWPF). Development of other serial Hanford Waste Vitrification System (HWVS) elements, such as the waste retrieval system for the double-shell tanks (DSTs), and the pretreatment system to reduce the waste volume converted into glass, also was required to accomplish permanent waste disposal. In July 1991, at the time of this review, the HWVP was in the Title 2 design phase. The objective of this technical assessment is to determine whether the status of the technology development and engineering practice is sufficient to provide reasonable assurance that the HWVP and the balance of the HWVS system will operate in an efficient and cost-effective manner. The criteria used to facilitate a judgment of potential successful operation are: vitrification of high-level radioactive waste from specified DSTs on a reasonably continuous basis; and glass produced with physical and chemical properties formally acknowledge as being acceptable for disposal in a repository for high-level radioactive waste. The criteria were proposed specifically for the Independent Engineering Review to focus that assessment effort. They are not represented as the criteria by which the Department will judge the prudence of the Project. 78 refs., 10 figs., 12 tabs.

  20. TOPICAL REVIEW: Stem cells engineering for cell-based therapy

    NASA Astrophysics Data System (ADS)

    Taupin, Philippe

    2007-09-01

    Stem cells carry the promise to cure a broad range of diseases and injuries, from diabetes, heart and muscular diseases, to neurological diseases, disorders and injuries. Significant progresses have been made in stem cell research over the past decade; the derivation of embryonic stem cells (ESCs) from human tissues, the development of cloning technology by somatic cell nuclear transfer (SCNT) and the confirmation that neurogenesis occurs in the adult mammalian brain and that neural stem cells (NSCs) reside in the adult central nervous system (CNS), including that of humans. Despite these advances, there may be decades before stem cell research will translate into therapy. Stem cell research is also subject to ethical and political debates, controversies and legislation, which slow its progress. Cell engineering has proven successful in bringing genetic research to therapy. In this review, I will review, in two examples, how investigators are applying cell engineering to stem cell biology to circumvent stem cells' ethical and political constraints and bolster stem cell research and therapy.

  1. Assessment of soot particle-size imaging with LII at Diesel engine conditions

    NASA Astrophysics Data System (ADS)

    Cenker, E.; Kondo, K.; Bruneaux, G.; Dreier, T.; Aizawa, T.; Schulz, C.

    2015-04-01

    Two-time-step laser-induced incandescence (LII) imaging was performed in Diesel engine-relevant combustion to investigate its applicability for spatially resolved measurements of soot primary particle sizes. The method is based on evaluating gated LII signals acquired with two cameras consecutively after the laser pulse and using LII modeling to deduce the particle size from the ratio of local signals. Based on a theoretical analysis, optimized detection times and durations were chosen to minimize measurement uncertainties. Experiments were conducted in a high-temperature high-pressure constant-volume pre-combustion vessel under the Engine Combustion Network's "Spray A" conditions at 61-68 bar with additional parametric variations in injection pressure, gas temperature, and composition. The LII measurements were supported by pyrometric imaging measurements of particle heat-up temperatures. The results were compared to particle-size and size-dispersion measurements from transmission electron microscopy of soot thermophoretically sampled at multiple axial distances from the injector. The discrepancies between the two measurement techniques are discussed to analyze uncertainties and related error sources of the two diagnostics. It is found that in such environment where particles are small and pressure is high, LII signal decay times are such that LII with standard nanosecond laser and detector equipment suffers from a strong bias toward large particles.

  2. A unique nuclear thermal rocket engine using a particle bed reactor

    NASA Astrophysics Data System (ADS)

    Culver, Donald W.; Dahl, Wayne B.; McIlwain, Melvin C.

    1992-01-01

    Aerojet Propulsion Division (APD) studied 75-klb thrust Nuclear Thermal Rocket Engines (NTRE) with particle bed reactors (PBR) for application to NASA's manned Mars mission and prepared a conceptual design description of a unique engine that best satisfied mission-defined propulsion requirements and customer criteria. This paper describes the selection of a sprint-type Mars transfer mission and its impact on propulsion system design and operation. It shows how our NTRE concept was developed from this information. The resulting, unusual engine design is short, lightweight, and capable of high specific impulse operation, all factors that decrease Earth to orbit launch costs. Many unusual features of the NTRE are discussed, including nozzle area ratio variation and nozzle closure for closed loop after cooling. Mission performance calculations reveal that other well known engine options do not support this mission.

  3. Modeling and Detection of Ice Particle Accretion in Aircraft Engine Compression Systems

    NASA Technical Reports Server (NTRS)

    May, Ryan D.; Simon, Donald L.; Guo, Ten-Huei

    2012-01-01

    The accretion of ice particles in the core of commercial aircraft engines has been an ongoing aviation safety challenge. While no accidents have resulted from this phenomenon to date, numerous engine power loss events ranging from uneventful recoveries to forced landings have been recorded. As a first step to enabling mitigation strategies during ice accretion, a detection scheme must be developed that is capable of being implemented on board modern engines. In this paper, a simple detection scheme is developed and tested using a realistic engine simulation with approximate ice accretion models based on data from a compressor design tool. These accretion models are implemented as modified Low Pressure Compressor maps and have the capability to shift engine performance based on a specified level of ice blockage. Based on results from this model, it is possible to detect the accretion of ice in the engine core by observing shifts in the typical sensed engine outputs. Results are presented in which, for a 0.1 percent false positive rate, a true positive detection rate of 98 percent is achieved.

  4. Particle trajectory computation on a 3-dimensional engine inlet. Final Report Ph.D. Thesis

    NASA Technical Reports Server (NTRS)

    Kim, J. J.

    1986-01-01

    A 3-dimensional particle trajectory computer code was developed to compute the distribution of water droplet impingement efficiency on a 3-dimensional engine inlet. The computed results provide the essential droplet impingement data required for the engine inlet anti-icing system design and analysis. The droplet trajectories are obtained by solving the trajectory equation using the fourth order Runge-Kutta and Adams predictor-corrector schemes. A compressible 3-D full potential flow code is employed to obtain a cylindrical grid definition of the flowfield on and about the engine inlet. The inlet surface is defined mathematically through a system of bi-cubic parametric patches in order to compute the droplet impingement points accurately. Analysis results of the 3-D trajectory code obtained for an axisymmetric droplet impingement problem are in good agreement with NACA experimental data. Experimental data are not yet available for the engine inlet impingement problem analyzed. Applicability of the method to solid particle impingement problems, such as engine sand ingestion, is also demonstrated.

  5. Pathogen-like particles: biomimetic vaccine carriers engineered at the nanoscale.

    PubMed

    Rosenthal, Joseph A; Chen, Linxiao; Baker, Jenny L; Putnam, David; DeLisa, Matthew P

    2014-08-01

    Vaccine adjuvants are an essential component of vaccine design, helping to generate immunity to pathogen antigens in the absence of infection. Recent advances in nanoscale engineering have created a new class of particulate bionanotechnology that uses biomimicry to better integrate adjuvant and antigen. These pathogen-like particles, or PLPs, can come from a variety of sources, ranging from fully synthetic platforms to biologically derived, self-assembling systems. By employing molecularly engineered targeting and stimulation of key immune cells, recent studies utilizing PLPs as vaccine delivery platforms have shown great promise against high-impact, unsolved vaccine targets ranging from bacterial and viral pathogens to cancer and addiction. PMID:24832075

  6. Quantum-Carnot engine for particle confined to 2D symmetric potential well

    SciTech Connect

    Belfaqih, Idrus Husin Sutantyo, Trengginas Eka Putra Prayitno, T. B.; Sulaksono, Anto

    2015-09-30

    Carnot model of heat engine is the most efficient cycle consisting of isothermal and adiabatic processes which are reversible. Although ideal gas usually used as a working fluid in the Carnot engine, Bender used quantum particle confined in 1D potential well as a working fluid. In this paper, by following Bender we generalize the situation to 2D symmetric potential well. The efficiency is express as the ratio of the initial length of the system to the final length of the compressed system. The result then is shown that for the same ratio, 2D potential well is more efficient than 1D potential well.

  7. Towards integrated drug substance and drug product design for an active pharmaceutical ingredient using particle engineering.

    PubMed

    Kougoulos, Eleftherios; Smales, Ian; Verrier, Hugh M

    2011-03-01

    A novel experimental approach describing the integration of drug substance and drug production design using particle engineering techniques such as sonocrystallization, high shear wet milling (HSWM) and dry impact (hammer) milling were used to manufacture samples of an active pharmaceutical ingredient (API) with diverse particle size and size distributions. The API instability was addressed using particle engineering and through judicious selection of excipients to reduce degradation reactions. API produced using a conventional batch cooling crystallization process resulted in content uniformity issues. Hammer milling increased fine particle formation resulting in reduced content uniformity and increased degradation compared to sonocrystallized and HSWM API in the formulation. To ensure at least a 2-year shelf life based on predictions using an Accelerated Stability Assessment Program, this API should have a D [v, 0.1] of 55 μm and a D [v, 0.5] of 140 μm. The particle size of the chief excipient in the drug product formulation needed to be close to that of the API to avoid content uniformity and stability issues but large enough to reduce lactam formation. The novel methodology described here has potential for application to other APIs. PMID:21246419

  8. Efficiency at maximum power of thermochemical engines with near-independent particles

    NASA Astrophysics Data System (ADS)

    Luo, Xiaoguang; Liu, Nian; Qiu, Teng

    2016-03-01

    Two-reservoir thermochemical engines are established by using near-independent particles (including Maxwell-Boltzmann, Fermi-Dirac, and Bose-Einstein particles) as the working substance. Particle and heat fluxes can be formed based on the temperature and chemical potential gradients between two different reservoirs. A rectangular-type energy filter with width Γ is introduced for each engine to weaken the coupling between the particle and heat fluxes. The efficiency at maximum power of each particle system decreases monotonously from an upper bound η+ to a lower bound η- when Γ increases from 0 to ∞ . It is found that the η+ values for all three systems are bounded by ηC/2 ≤η+≤ηC/(2 -ηC ) due to strong coupling, where ηC is the Carnot efficiency. For the Bose-Einstein system, it is found that the upper bound is approximated by the Curzon-Ahlborn efficiency: ηCA=1 -√{1 -ηC } . When Γ →∞ , the intrinsic maximum powers are proportional to the square of the temperature difference of the two reservoirs for all three systems, and the corresponding lower bounds of efficiency at maximum power can be simplified in the same form of η-=ηC/[1 +a0(2 -ηC ) ] .

  9. Abrasive wear by diesel engine coal-fuel and related particles

    SciTech Connect

    Ives, L.K.

    1994-09-01

    The purpose of the work summarized in this report was to obtain a basic understanding of the factors which are responsible for wear of the piston ring and cylinder wall surfaces in diesel engines utilizing coal-fuel. The approach included analytical studies using scanning electron microscopy and energy dispersive x-ray analyses to characterize coal-fuel and various combustion particles, and two different wear tests. The wear tests were a modified pin-on-disk test and a block-on-ring test capable of either unidirectional or reciprocating-rotational sliding. The wear tests in general were conducted with mixtures of the particles and lubricating oil. The particles studied included coal-fuel, particles resulting from the combustion of coal fuel, mineral matter extracted during the processing of coal, and several other common abrasive particle types among which quartz was the most extensively examined. The variables studied included those associated with the particles, such as particle type, size, and hardness; variables related to contact conditions and the surrounding environment; and variables related to the type and properties of the test specimen materials.

  10. A New Class of Engineering Materials: Particle-Stabilized Metallic Emulsions and Monotectic Alloys

    NASA Astrophysics Data System (ADS)

    Budai, István; Kaptay, George

    2009-07-01

    Al-matrix particulate composites are melted and mixed with immiscible metals to form their small droplets in liquid aluminum. It is shown that, in the Al-Si/SiC/Bi system, the Bi droplets are stabilized by the SiC particles in the liquid Al matrix. Upon solidification, homogeneous distribution of solidified Bi droplets is obtained in the Al matrix at the bottom part of the ingot. Thus, a new class of engineering materials (particle-stabilized monotectic alloys) is obtained.

  11. A review on stereolithography and its applications in biomedical engineering.

    PubMed

    Melchels, Ferry P W; Feijen, Jan; Grijpma, Dirk W

    2010-08-01

    Stereolithography is a solid freeform technique (SFF) that was introduced in the late 1980s. Although many other techniques have been developed since then, stereolithography remains one of the most powerful and versatile of all SFF techniques. It has the highest fabrication accuracy and an increasing number of materials that can be processed is becoming available. In this paper we discuss the characteristic features of the stereolithography technique and compare it to other SFF techniques. The biomedical applications of stereolithography are reviewed, as well as the biodegradable resin materials that have been developed for use with stereolithography. Finally, an overview of the application of stereolithography in preparing porous structures for tissue engineering is given. PMID:20478613

  12. [Biosynthesis and metabolic engineering of dithiolopyrrolone - A review].

    PubMed

    Huang, Sheng; Yu, Yi

    2016-03-01

    Dithiolopyrrolones are a family of antibiotics that possess the unique pyrrolinonodithiole (4H-[1,2] dithiolo [4, 3-b] pyrrol-5-one) skeleton. This family of natural products can be divided into three subfamilies: N-methyl-N- acylpyrrothine, N-acylpyrrothine and thiomarinols. So far, more than 27 members of this group of natural products have been reported including the well-known antibiotics holomycin, thiolutin, aureothricin and recently isolated thiomarinols. Dithiolopyrrolones exhibit relatively broad-spectrum antibiotic activities against many Gram-positive, Gram-negative bacteria and parasites. Some dithiolopyrrolones even have antitumor activities. In recent years, several dithiolopyrrolone biosynthetic gene clusters have been reported and their biosynthetic mechanisms have also been intensively studied. This review will give an overview about the biosynthesis and metabolic engineering of the dithiolopyrrolone natural products, and provides references to guide the creation of hybrid "unnatural" dithiolopyrrolones with better bioactivity and low toxicity by synthetic biology. PMID:27382782

  13. Tendon Reconstruction with Tissue Engineering Approach--A Review.

    PubMed

    Verdiyeva, Gunay; Koshy, Kiron; Glibbery, Natalia; Mann, Haroon; Seifalian, Alexander M

    2015-09-01

    Tendon injuries are a common and rising occurrence, associated with significant impairment to quality of life and financial burden to the healthcare system. Clinically, they represent an unresolved problem, due to poor natural tendon healing and the inability of current treatment strategies to restore the tendon to its native state. Tissue engineering offers a promising alternative, with the incorporation of scaffolds, cells and growth factors to support the complete regeneration of the tendon. The materials used in tendon engineering to date have provided significant advances in structural integrity and biological compatibility and in many cases the results obtained are superior to those observed in natural healing. However, grafts fail to reproduce the qualities of the pre-injured tendon and each has weaknesses subject to its constituent parts. Furthermore, many materials and cell types are being investigated concurrently, with seemingly little association or comparison between research results. In this review the properties of the most-investigated and effective components have been appraised in light of the surrounding literature, with research from early in-vitro experiments to clinical trials being discussed. Extensive comparisons have been made between scaffolds, cell types and growth factors used, listing strengths and weaknesses to provide a stable platform for future research. Promising future endeavours are also described in the field of nanocomposite material science, stem cell sources and growth factors, which may bypass weaknesses found in individual elements. The future of tendon engineering looks bright, with growing understanding in material technology, cell and growth factor application and encouraging recent advances bringing us ever closer to regenerating the native tendon. PMID:26485923

  14. Tissue Engineering and Regenerative Medicine 2015: A Year in Review.

    PubMed

    Wobma, Holly; Vunjak-Novakovic, Gordana

    2016-04-01

    This may be the most exciting time ever for the field of tissue engineering and regenerative medicine (TERM). After decades of progress, it has matured, integrated, and diversified into entirely new areas, and it is starting to make the pivotal shift toward translation. The most exciting science and applications continue to emerge at the boundaries of disciplines, through increasingly effective interactions between stem cell biologists, bioengineers, clinicians, and the commercial sector. In this "Year in Review," we highlight some of the major advances reported over the last year (Summer 2014-Fall 2015). Using a methodology similar to that established in previous years, we identified four areas that generated major progress in the field: (i) pluripotent stem cells, (ii) microtissue platforms for drug testing and disease modeling, (iii) tissue models of cancer, and (iv) whole organ engineering. For each area, we used some of the most impactful articles to illustrate the important concepts and results that advanced the state of the art of TERM. We conclude with reflections on emerging areas and perspectives for future development in the field. PMID:26714410

  15. Physical characterization of the fine particle emissions from commercial aircraft engines during the Aircraft Particle Emissions Experiment (APEX) 1 to 3

    EPA Science Inventory

    The f1me particulate matter (PM) emissions from nine commercial aircraft engine models were determined by plume sampling during the three field campaigns of the Aircraft Particle Emissions Experiment (APEX). Ground-based measurements were made primarily at 30 m behind the engine ...

  16. Chemical characterization of the fine particle emissions from commercial aircraft engines during the Aircraft Particle Emissions eXperiment (APEX) 1 to 3

    EPA Science Inventory

    This paper addresses the need for detailed chemical information on the fine particulate matter (PM2.5) generated by commercial aviation engines. The exhaust plumes of nine engine models were sampled during the three test campaigns of the Aircraft Particle Emissions eXperiment (AP...

  17. Effects of Gasoline Direct Injection Engine Operating Parameters on Particle Number Emissions

    SciTech Connect

    He, X.; Ratcliff, M. A.; Zigler, B. T.

    2012-04-19

    A single-cylinder, wall-guided, spark ignition direct injection engine was used to study the impact of engine operating parameters on engine-out particle number (PN) emissions. Experiments were conducted with certification gasoline and a splash blend of 20% fuel grade ethanol in gasoline (E20), at four steady-state engine operating conditions. Independent engine control parameter sweeps were conducted including start of injection, injection pressure, spark timing, exhaust cam phasing, intake cam phasing, and air-fuel ratio. The results show that fuel injection timing is the dominant factor impacting PN emissions from this wall-guided gasoline direct injection engine. The major factor causing high PN emissions is fuel liquid impingement on the piston bowl. By avoiding fuel impingement, more than an order of magnitude reduction in PN emission was observed. Increasing fuel injection pressure reduces PN emissions because of smaller fuel droplet size and faster fuel-air mixing. PN emissions are insensitive to cam phasing and spark timing, especially at high engine load. Cold engine conditions produce higher PN emissions than hot engine conditions due to slower fuel vaporization and thus less fuel-air homogeneity during the combustion process. E20 produces lower PN emissions at low and medium loads if fuel liquid impingement on piston bowl is avoided. At high load or if there is fuel liquid impingement on piston bowl and/or cylinder wall, E20 tends to produce higher PN emissions. This is probably a function of the higher heat of vaporization of ethanol, which slows the vaporization of other fuel components from surfaces and may create local fuel-rich combustion or even pool-fires.

  18. Particles from a Diesel ship engine: Mixing state on the nano scale and cloud condensation abilities

    NASA Astrophysics Data System (ADS)

    Lieke, K. I.; Rosenørn, T.; Fuglsang, K.; Frederiksen, T.; Butcher, A. C.; King, S. M.; Bilde, M.

    2012-04-01

    Transport by ship plays an important role in global logistics. Current international policy initiatives by the International Maritime Organization (IMO) are taken to reduce emissions from ship propulsion systems (NO and SO, primarily). However, particulate emissions (e.g. soot) from ships are yet not regulated by legislations. To date, there is still a lack of knowledge regarding the global and local effects of the particulate matter emitted from ships at sea. Particles may influence the climate through their direct effects (scattering and absorption of long and shortwave radiation) and indirectly through formation of clouds. Many studies have been carried out estimating the mass and particle number from ship emissions (e.g. Petzold et al. 2008), many of them in test rig studies (e.g. Kasper et al. 2007). It is shown that particulate emissions vary with engine load and chemical composition of fuels. Only a few studies have been carried out to characterize the chemical composition and cloud-nucleating ability of the particulate matter (e.g. Corbett et al. 1997). In most cases, the cloud-nucleating ability of emission particles is estimated from number size distribution. We applied measurements to characterize particulate emissions from a MAN B&W Low Speed engine on test bed. A unique data set was obtained through the use of a scanning mobility particle sizing system (SMPS), combined with a cloud condensation nucleus (CCN) counter and a thermodenuder - all behind a dilution system. In addition, impactor samples were taken on nickel grids with carbon foil for use in an electron microscope (EM) to characterize the mineral phase and mixing state of the particles. The engine was operated at a series of different load conditions and an exhaust gas recirculation (EGR) system was applied. Measurements were carried out before and after the EGR system respectively. Our observations show significant changes in number size distribution and CCN activity with varying conditions

  19. Engineering tubular bone using mesenchymal stem cell sheets and coral particles

    SciTech Connect

    Geng, Wenxin; Ma, Dongyang; Yan, Xingrong; Liu, Liangqi; Cui, Jihong; Xie, Xin; Li, Hongmin; Chen, Fulin

    2013-04-19

    Highlights: • We developed a novel engineering strategy to solve the limitations of bone grafts. • We fabricated tubular constructs using cell sheets and coral particles. • The composite constructs showed high radiological density and compressive strength. • These characteristics were similar to those of native bone. -- Abstract: The development of bone tissue engineering has provided new solutions for bone defects. However, the cell-scaffold-based approaches currently in use have several limitations, including low cell seeding rates and poor bone formation capacity. In the present study, we developed a novel strategy to engineer bone grafts using mesenchymal stem cell sheets and coral particles. Rabbit bone marrow mesenchymal stem cells were continuously cultured to form a cell sheet with osteogenic potential and coral particles were integrated into the sheet. The composite sheet was then wrapped around a cylindrical mandrel to fabricate a tubular construct. The resultant tubular construct was cultured in a spinner-flask bioreactor and subsequently implanted into a subcutaneous pocket in a nude mouse for assessment of its histological characteristics, radiological density and mechanical property. A similar construct assembled from a cell sheet alone acted as a control. In vitro observations demonstrated that the composite construct maintained its tubular shape, and exhibited higher radiological density, compressive strength and greater extracellular matrix deposition than did the control construct. In vivo experiments further revealed that new bone formed ectopically on the composite constructs, so that the 8-week explants of the composite sheets displayed radiological density similar to that of native bone. These results indicate that the strategy of using a combination of a cell sheet and coral particles has great potential for bone tissue engineering and repairing bone defects.

  20. Biological activity of particle exhaust emissions from light-duty diesel engines.

    PubMed

    Carraro, E; Locatelli, A L; Ferrero, C; Fea, E; Gilli, G

    1997-01-01

    Whole diesel exhaust has been classified recently as a probable carcinogen, and several genotoxicity studies have found particulate exhaust to be clearly mutagenic. Moreover, genotoxicity of diesel particulate is greatly influenced by fuel nature and type of combustion. In order to obtain an effective environmental pollution control, combustion processes using alternative fuels are being analyzed presently. The goal of this study is to determine whether the installation of exhaust after treatment-devices on two light-duty, exhaust gas recirculation (EGR) valve-equipped diesel engines (1930 cc and 2500 cc) can reduce the mutagenicity associated with particles collected during U.S.A. and European driving cycles. Another interesting object was to compare the ability of alternative biodiesel and conventional diesel fuels to reduce the mutagenic activity associated with collected particles from two light duty diesel engines (both 1930 cc) during the European driving cycle. SOF mutagenicity was assayed using the Salmonella/microsome test (TA 98 and TA 100 strains, +/- S9 fraction). In the first part of our study, the highest mutagenicity was revealed by TA98 strain without enzymatic activation, suggesting a direct-acting mutagenicity prevalence in diesel particulate. The 2500 cc engine revealed twofold mutagenic activity compared with the 1930 cc engine (both EGR valve equipped), whereas an opposite result was found in particulate matter amount. The use of a noncatalytic ceramic trap produced a decrease of particle mutagenic activity in the 2500 cc car, whereas an enhancement in the 1930 cc engine was found. The catalytic converter and the electrostatic filter installed on the 2500 cc engine yielded a light particle amount and an SOF mutagenicity decrease. A greater engine stress was obtained using European driving cycles, which caused the strongest mutagenicity/km compared with the U.S.A. cycles. In the second part of the investigation, even though a small number of

  1. 2015 Space Human Factors Engineering Standing Review Panel

    NASA Technical Reports Server (NTRS)

    Steinberg, Susan

    2015-01-01

    The 2015 Space Human Factors Engineering (SHFE) Standing Review Panel (from here on referred to as the SRP) met for a site visit in Houston, TX on December 2 - 3, 2015. The SRP reviewed the updated research plans for the Risk of Inadequate Design of Human and Automation/Robotic Integration (HARI Risk), the Risk of Inadequate Human-Computer Interaction (HCI Risk), and the Risk of Inadequate Mission, Process and Task Design (MPTask Risk). The SRP also received a status update on the Risk of Incompatible Vehicle/Habitat Design (Hab Risk) and the Risk of Performance Errors Due to Training Deficiencies (Train Risk). The SRP is pleased with the progress and responsiveness of the SHFE team. The presentations were much improved this year. The SRP is also pleased with the human-centered design approach. Below are some of the more extensive comments from the SRP. We have also made comments in each section concerning gaps/tasks in each. The comments below reflect more significant changes that impact more than just one particular section.

  2. Generic Engineering Competencies: A Review and Modelling Approach

    ERIC Educational Resources Information Center

    Male, Sally A.

    2010-01-01

    This paper puts forward the view that engineering educators have a responsibility to prepare graduates for engineering work and careers. The current literature reveals gaps between the competencies required for engineering work and those developed in engineering education. Generic competencies feature in these competency gaps. Literature suggests…

  3. 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

  4. 77 FR 18268 - Proposal Review Panel for Engineering Education and Centers; Notice of Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-27

    ... From the Federal Register Online via the Government Publishing Office NATIONAL SCIENCE FOUNDATION Proposal Review Panel for Engineering Education and Centers; Notice of Meeting In accordance with the... the following meeting: Name: Proposal Review Panel for Engineering Education and Centers ( 173)....

  5. 77 FR 3844 - Agency Information Collection (Architect-Engineer Fee Proposal) Activity Under OMB Review

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-25

    ... AFFAIRS Agency Information Collection (Architect--Engineer Fee Proposal) Activity Under OMB Review AGENCY...: a. Architect--Engineer Fee Proposal, VA Form 10-6298. b. Daily Log (Contract Progress Report--Formal...: 2900-0208. Type of Review: Extension of a currently approved collection. ] Abstracts: a. An...

  6. Surface-Engineered Graphene Quantum Dots for Shape Control of Block Copolymer Particles

    NASA Astrophysics Data System (ADS)

    Yang, Hyunseung; Ku, Kang Hee; Shin, Jae Man; Lee, Junhyuk; Park, Chan Ho; Cho, Han-Hee; Jang, Se Gyu; Kim, Bumjoon; KIST Collaboration

    Surface-engineered, 10 nm-sized graphene quantum dots (GQDs) are shown to be efficient surfactants for producing poly(styrene-b-4-vinylpyridine) (PS-b-P4VP) particles that feature tunable shapes and internal morphologies. The surface properties of GQDs were modified by grafting different alkyl ligands, such as hexylamine and oleylamine, to generate the surfactant behavior of the GQDs. In stark contrast to the behavior of the unmodified GQDs, hexylamine-grafted GQDs and oleylamine-grafted GQD surfactants were selectively positioned on the PS and P4VP domains, respectively, at the surface of the particles. This positioning effectively tuned the interfacial interaction between two different PS/P4VP domains of the particles and the surrounding water during emulsification and induced a dramatic morphological transition to an unconventional convex lens-shaped particles. Precise and systematic control of interfacial activity of GQD surfactants was also demonstrated by varying the density of the alkyl ligands on the GQDs. The excellent surface tunability of 10 nm-sized GQDs combined with their significant optical and electrical properties highlight their importance as surfactants for producing colloidal particles with novel functions.

  7. 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.

  8. 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

  9. Engineering gas-foamed large porous particles for efficient local delivery of macromolecules to the lung.

    PubMed

    Ungaro, Francesca; Giovino, Concetta; Coletta, Ciro; Sorrentino, Raffaella; Miro, Agnese; Quaglia, Fabiana

    2010-09-11

    Gas-foamed large porous particles (gfLPP) based on poly(lactic-co-glycolic) acid (PLGA) have been recently suggested as potential carriers for pulmonary drug delivery. In this work, we attempt to engineer gfLPP for efficient local delivery of macromolecules in the lungs. Particles were fabricated by the double emulsion-solvent evaporation technique using ammonium bicarbonate as porogen. To improve particle technological properties, two lipid aid excipients, namely dipalmitoylphosphatidylcholine (DPPC) and 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP), were tested. Preliminary technological studies performed on unloaded gfLPP showed that the addition of an appropriate amount of NH(4)(HCO(3)), which spontaneously produces CO(2) and NH(3) during solvent evaporation, is essential to achieve a homogeneous population of highly porous particles with optimal aerodynamic properties. Then, the effect of the presence of DPPC or DOTAP upon the properties of gfLPP containing a model hydrophilic macromolecule, rhodamine B isothiocyanate-dextran (Rhod-dex), was assessed. We found that in the case of hydrophilic macromolecules unable to interact with PLGA end-groups, such as Rhod-dex, excipient addition is essential to increase the amount of drug entrapped within gfLPP, being as high as 80% only for DPPC- or DOTAP-engineered gfLPP. Also Rhod-dex release profile from gfLPP was strongly affected by excipient addition in the initial formulation, with lipid-engineered gfLPP allowing for a more prolonged release of Rhod-dex as compared to excipient-free gfLPP. A further modulation of Rhod-dex initial release rate could be achieved when DOTAP was used, likely due to the electrostatic interactions occurring between macromolecule and cationic phospholipid. Conceiving the developed gfLPP for drug inhalation, DPPC- and DOTAP-engineered gfLPP displayed optimal MMAD(exp) values falling within the range 6.1-7.6 microm and very low geometric standard deviations (GSD) varying between 1.2 and

  10. Particle Size Distributions Measured in the B757 Engine Plume During EXCAVATE

    NASA Technical Reports Server (NTRS)

    Sanders, Terry; Penko, Paul; Rivera, Monica; Culler, Steve

    2005-01-01

    The Experiment to Characterize Aircraft Volatile Aerosols and Trace Species Emissions (EXCAVATE) took place at NASA Langley Research Center during January 2002. This ground based study was conducted to examine the role of fuel sulfur content on particulate emissions. Size distributions as a function of engine operating conditions were measured in the exhaust plume of a B-757 at four downstream axial locations (1 m, 10 m, 25 m and 35 m). The engine was run on JP-5 with three different sulfur concentrations, 810 ppm, 1050 ppm, 1820 ppm; and was operated over a range of power settings from idle to near-full power. Zalabsky differential-mobility analyzers DMAS), Met One condensation-nuclei counters (CNCs), and a TSI 3022 condensation-particle counter (CPC) were used to measure the size distributions. The total number-count (particle concentration), number-based Emissions Index (EInumber) and mass-based Emissions Index (E1-J increased with fuel sulfur-content and engine pressure ratio (EPR). Count Mean Diameter (Ch4D) also increased with EPR yet remained fairly constant with fuel sulfur-content for a fixed location in the exhaust plume. Also the mode and CMD both increased with distance in the plume.

  11. Tracing Gas and Particle Phase Oxidation From Engine Sources as a Function of Fuel Type, Load, and Photochemical Age

    NASA Astrophysics Data System (ADS)

    Friedman, B.; Farmer, D.; Jathar, S.; Galang, A.; Fulgham, R.; Link, M.; Brophy, P.

    2015-12-01

    Motor vehicle emissions are an important source of anthropogenic gases and particles in the atmosphere. To study the gas and particle phase emissions, an HR-TOF-AMS and HR-TOF-CIMS were deployed at the CSU Engines Lab, along with an oxidative flow reactor, to measure emissions from a 4.5 L John Deere engine, which ran either diesel or biodiesel fuel. Concurrent gas-phase and particle-phase measurements allowed determination of the gas-phase and particle-phase oxidation properties as a function of fuel type, fuel load, and photochemical age. The impacts of particulate filers on composition and oxidation state were also assessed. While aerosol composition and associated oxidation properties for the biodiesel and diesel fuel types were similar, differences in photochemical production existed for the amount of load, or efficiency of the engine. The mean particulate oxygen to carbon ratios (O:C) and mean hydrogen to carbon ratios (H:C) moved from an initial 0.1 and 2 to a final 0.55 and 1.6, respectively, upon idle biodiesel and diesel engine exhaust exposure to approximately 7 days of OH exposure. The more efficient higher load biodiesel and diesel engine exhaust experienced less changes in the mean O:C and H:C values (an initial 0.1 and 2 to a final 0.3 and 1.7, respectively) with approximately the same amount of OH exposure. Despite largely scrubbing the majority of particles from the engine exhaust, experiments with engine particulate filters still showed photochemical production of oxidized particle-phase species at high photochemical ages, similar to that of idle engine exhaust without any particulate filters. Bulk gas-phase data was compared to bulk aerosol data in Van Krevelen space in order to understand how particle-phase oxidation traces gas-phase oxidation as a function of fuel type, engine load, and photochemical age.

  12. Airborne monitoring to distinguish engineered nanomaterials from incidental particles for environmental health and safety.

    PubMed

    Peters, Thomas M; Elzey, Sherrie; Johnson, Ronald; Park, Heaweon; Grassian, Vicki H; Maher, Tabitha; O'Shaughnessy, Patrick

    2009-02-01

    Two methods were used to distinguish airborne engineered nanomaterials from other airborne particles in a facility that produces nano-structured lithium titanate metal oxide powder. The first method involved off-line analysis of filter samples collected with conventional respirable samplers at each of seven locations (six near production processes and one outdoors). Throughout most of the facility and outdoors, respirable mass concentrations were low (<0.050 mg/m(3)) and were attributed to particles other than the nanomaterial (<10% by mass titanium determined with inductively coupled plasma atomic emission spectrometry). In contrast, in a single area with extensive material handling, mass concentrations were greatest (0.118 mg m(-3)) and contained up to 39% +/- 11% lithium titanium, indicating the presence of airborne nanomaterial. Analysis of the filter samples collected in this area by transmission electron microscope and scanning electron microscope revealed that the airborne nanomaterial was associated only with spherical aggregates (clusters of fused 10-80 nm nanoparticles) that were larger than 200 nm. This analysis also showed that nanoparticles in this area were the smallest particles of a larger distribution of submicrometer chain agglomerates likely from welding in an adjacent area of the facility. The second method used two, hand-held, direct-reading, battery-operated instruments to obtain a time series of very fine particle number (<300 nm), respirable mass, and total mass concentration, which were then related to activities within the area of extensive material handling. This activity-based monitoring showed that very fine particle number concentrations (<300 nm) had no apparent correlation to worker activities, but that sharp peaks in the respirable and total mass concentration coincided with loading a hopper and replacing nanomaterial collection bags. These findings were consistent with those from the filter-based method in that they demonstrate

  13. Airborne monitoring to distinguish engineered nanomaterials from incidental particles for environmental health and safety

    PubMed Central

    Peters, TM; Elzey, S; Johnson, R; Park, H; Grassian, VH; Maher, T; O'Shaughnessy, P

    2016-01-01

    Two methods were used to distinguish airborne engineered nanomaterials from other airborne particles in a facility that produces nano-structured lithium titanate metal oxide powder. The first method involved off-line analysis of filter samples collected with conventional respirable samplers at each of seven locations (six near production processes and one outdoors). Throughout most of the facility and outdoors, respirable mass concentrations were low (<0.050 mg m−3) and were attributed to particles other than the nanomaterial (<10% by mass titanium determined with inductively coupled plasma atomic emission spectrometry). In contrast, in a single area with extensive material handling, mass concentrations were greatest (0.118 mg m−3) and contained up to 39% +/− 11% lithium titanium, indicating the presence of airborne nanomaterial. Analysis of the filter samples collected in this area by transmission electron microscope and scanning electron microscope revealed that the airborne nanomaterial was associated only with spherical aggregates (clusters of fused 10–80 nm nanoparticles) that were larger than 200 nm. This analysis also showed that nanoparticles in this area were the smallest particles of a larger distribution of submicrometer chain agglomerates likely from welding in an adjacent area of the facility. The second method used two, hand-held, direct-reading, battery-operated instruments to obtain a time series of very fine particle number (<300 nm), respirable mass, and total mass concentration, which were then related to activities within the area of extensive material handling. This activity-based monitoring showed that very fine particle number concentrations (<300 nm) had no apparent correlation to worker activities, but that sharp peaks in the respirable and total mass concentration coincided with loading a hopper and replacing nanomaterial collection bags. These findings were consistent with those from the filter-based method in that they

  14. Development and Application of A Membrane-Based Thermodenuder for Measurement of Volatile Particles Emitted by A Jet Turbine Engine

    SciTech Connect

    Cheng, Mengdawn

    2010-01-01

    Measurement of volatile particles emitted by modern jet engines is a daunting task. Besides the complexity in sampling jet aircraft exhaust, the main difficulty lies at how to faithfully capture the phase-partition dynamics of volatile particles as they travel downstream from the engine exhaust nozzle. As a result, the physico-chemical properties of the exhaust are also transformed. We have developed a sampling instrument that aims at enabling study of the phase-partition dynamics. The objective of this research project was to design and evaluate a new thermodenuder for performing phase separation of the engine-emitted volatile particles. The backbone of the new thermodenuder is a thin metallic membrane. The membrane enables extraction of molecules that can be thermally desorbed from the condensed particulate phases and collected for subsequent chemical analysis. Toward realization of the technique in the future field aircraft emissions measurement we tested this new thermo-denuding device using laboratory-generated particles that were made of non-volatile or semi-volatile chemicals. The particle penetration efficiency, a measure of the device performance, of this thermodenuder was found to be better than 99%. Results obtained from the tests executed at a number of operating temperature conditions show reasonably good thermal separation. We have scheduled to apply this new device to characterize emissions from a T63 turboshaft engine in the spring of 2010 and are expecting to show the engine results at the conference. The test results based on the laboratory-generated particles were encouraging for the intended application. With excellent particle transmission efficiency and an ability to simultaneously measure the composition in the gas and particle phases of the engine particles, we believe the new technology will make a great contribution to measurement research of engine emissions.

  15. The Problem of Engineering Creativity in Russia: A Critical Review

    ERIC Educational Resources Information Center

    Kukushkin, Sergey; Churlyaeva, Natalya

    2012-01-01

    The problem of technological creativity in Russia is briefly discussed. Special attention is paid to the development of indigenous engineering corpus in unfavourable conditions and some reasons for engineers' low creativity are revealed. The Soviet system of engineering higher education (HE) is criticised as not focused on fostering creative…

  16. A review of Curtiss-Wright rotary engine developments with respect to general aviation potential

    NASA Technical Reports Server (NTRS)

    Jones, C.

    1979-01-01

    Aviation related rotary (Wankel-type) engine tests, possible growth directions and relevant developments at Curtiss-Wright have been reviewed. Automotive rotary engines including stratified charge are described and flight test results of rotary aircraft engines are presented. The current 300 HP engine prototype shows basic durability and competitive performance potential. Recent parallel developments have separately confirmed the geometric advantages of the rotary engine for direct injected unthrottled stratified charge. Specific fuel consumption equal to or better than pre- or swirl-chamber diesels, low emission and multi-fuel capability have been shown by rig tests of similar rotary engine.

  17. Formation mechanism of chalcogenide nanocrystals confined inside genetically engineered virus-like particles

    NASA Astrophysics Data System (ADS)

    Zhou, Ziyou; Bedwell, Gregory J.; Li, Rui; Prevelige, Peter E.; Gupta, Arunava

    2014-01-01

    Engineered virus-like particles (VLP) are attractive for fabricating nanostructured materials for applications in diverse areas such as catalysis, drug delivery, biomedicine, composites, etc. Basic understanding of the interaction between the inorganic guest and biomolecular host is thus important for the controlled synthesis of inorganic nanoparticles inside VLP and rational assembly of ordered VLP-based hierarchical nanostructures. We have investigated in detail the formation mechanism and growth kinetics of semiconducting nanocrystals confined inside genetically engineered bacteriophage P22 VLP using semiconducting CdS as a prototypical example. The selective nucleation and growth of CdS at the engineered sites is found to be uniform during the early stage, followed by a more stochastic growth process. Furthermore, kinetic studies reveal that the presence of an engineered biotemplate helps in significantly retarding the reaction rate. These findings provide guidance for the controlled synthesis of a wide range of other inorganic materials confined inside VLP, and are of practical importance for the rational design of VLP-based hierarchical nanostuctures.

  18. Quantum heat engine in the relativistic limit: the case of a Dirac particle.

    PubMed

    Muñoz, Enrique; Peña, Francisco J

    2012-12-01

    We studied the efficiency of two different schemes for a quantum heat engine, by considering a single Dirac particle trapped in an infinite one-dimensional potential well as the "working substance." The first scheme is a cycle, composed of two adiabatic and two isoenergetic reversible trajectories in configuration space. The trajectories are driven by a quasistatic deformation of the potential well due to an external applied force. The second scheme is a variant of the former, where isoenergetic trajectories are replaced by isothermal ones, along which the system is in contact with macroscopic thermostats. This second scheme constitutes a quantum analog of the classical Carnot cycle. Our expressions, as obtained from the Dirac single-particle spectrum, converge in the nonrelativistic limit to some of the existing results in the literature for the Schrödinger spectrum. PMID:23367894

  19. Effect of Compressibility on Contrail Ice Particle Growth in an Engine Jet

    NASA Astrophysics Data System (ADS)

    Garnier, François; Maglaras, Ephi; Morency, François; Vancassel, Xavier

    2014-06-01

    In order to understand the formation process of condensation trails (contrails), the flow in the near field of an aircraft engine jet is studied by using the three-dimensional Large Eddy Simulation technique. The configuration consists of a hot round jet laden with soot particles. The particles are tracked using the Lagrangian approach, and their growth is calculated by a microphysics water vapour deposition model. A series of simulations are performed at a realistic Reynolds number (Re = 3.2 · 106) for two different jet Mach numbers: quasi-incompressible jet flow (M = 0.2) and compressible jet flow (M = 1). Whatever the Mach number used the ice crystals first appear at the edges of the jet where the hot and moist flow mixes with the cold and dry ambient air. Both the thermal transfers and the mass coupling, which are more significant for the quasi-incompressible jet flow, control the growth process.

  20. Invited Review: A review of deterministic effects in cyclic variability of internal combustion engines

    SciTech Connect

    Finney, Charles E.; Kaul, Brian C.; Daw, C. Stuart; Wagner, Robert M.; Edwards, K. Dean; Green, Johney B.

    2015-02-18

    Here we review developments in the understanding of cycle to cycle variability in internal combustion engines, with a focus on spark-ignited and premixed combustion conditions. Much of the research on cyclic variability has focused on stochastic aspects, that is, features that can be modeled as inherently random with no short term predictability. In some cases, models of this type appear to work very well at describing experimental observations, but the lack of predictability limits control options. Also, even when the statistical properties of the stochastic variations are known, it can be very difficult to discern their underlying physical causes and thus mitigate them. Some recent studies have demonstrated that under some conditions, cyclic combustion variations can have a relatively high degree of low dimensional deterministic structure, which implies some degree of predictability and potential for real time control. These deterministic effects are typically more pronounced near critical stability limits (e.g. near tipping points associated with ignition or flame propagation) such during highly dilute fueling or near the onset of homogeneous charge compression ignition. We review recent progress in experimental and analytical characterization of cyclic variability where low dimensional, deterministic effects have been observed. We describe some theories about the sources of these dynamical features and discuss prospects for interactive control and improved engine designs. In conclusion, taken as a whole, the research summarized here implies that the deterministic component of cyclic variability will become a pivotal issue (and potential opportunity) as engine manufacturers strive to meet aggressive emissions and fuel economy regulations in the coming decades.

  1. Invited Review: A review of deterministic effects in cyclic variability of internal combustion engines

    DOE PAGESBeta

    Finney, Charles E.; Kaul, Brian C.; Daw, C. Stuart; Wagner, Robert M.; Edwards, K. Dean; Green, Johney B.

    2015-02-18

    Here we review developments in the understanding of cycle to cycle variability in internal combustion engines, with a focus on spark-ignited and premixed combustion conditions. Much of the research on cyclic variability has focused on stochastic aspects, that is, features that can be modeled as inherently random with no short term predictability. In some cases, models of this type appear to work very well at describing experimental observations, but the lack of predictability limits control options. Also, even when the statistical properties of the stochastic variations are known, it can be very difficult to discern their underlying physical causes andmore » thus mitigate them. Some recent studies have demonstrated that under some conditions, cyclic combustion variations can have a relatively high degree of low dimensional deterministic structure, which implies some degree of predictability and potential for real time control. These deterministic effects are typically more pronounced near critical stability limits (e.g. near tipping points associated with ignition or flame propagation) such during highly dilute fueling or near the onset of homogeneous charge compression ignition. We review recent progress in experimental and analytical characterization of cyclic variability where low dimensional, deterministic effects have been observed. We describe some theories about the sources of these dynamical features and discuss prospects for interactive control and improved engine designs. In conclusion, taken as a whole, the research summarized here implies that the deterministic component of cyclic variability will become a pivotal issue (and potential opportunity) as engine manufacturers strive to meet aggressive emissions and fuel economy regulations in the coming decades.« less

  2. Biomechanical effects of environmental and engineered particles on human airway smooth muscle cells

    PubMed Central

    Berntsen, P.; Park, C. Y.; Rothen-Rutishauser, B.; Tsuda, A.; Sager, T. M.; Molina, R. M.; Donaghey, T. C.; Alencar, A. M.; Kasahara, D. I.; Ericsson, T.; Millet, E. J.; Swenson, J.; Tschumperlin, D. J.; Butler, J. P.; Brain, J. D.; Fredberg, J. J.; Gehr, P.; Zhou, E. H.

    2010-01-01

    The past decade has seen significant increases in combustion-generated ambient particles, which contain a nanosized fraction (less than 100 nm), and even greater increases have occurred in engineered nanoparticles (NPs) propelled by the booming nanotechnology industry. Although inhalation of these particulates has become a public health concern, human health effects and mechanisms of action for NPs are not well understood. Focusing on the human airway smooth muscle cell, here we show that the cellular mechanical function is altered by particulate exposure in a manner that is dependent upon particle material, size and dose. We used Alamar Blue assay to measure cell viability and optical magnetic twisting cytometry to measure cell stiffness and agonist-induced contractility. The eight particle species fell into four categories, based on their respective effect on cell viability and on mechanical function. Cell viability was impaired and cell contractility was decreased by (i) zinc oxide (40–100 nm and less than 44 μm) and copper(II) oxide (less than 50 nm); cell contractility was decreased by (ii) fluorescent polystyrene spheres (40 nm), increased by (iii) welding fumes and unchanged by (iv) diesel exhaust particles, titanium dioxide (25 nm) and copper(II) oxide (less than 5 μm), although in none of these cases was cell viability impaired. Treatment with hydrogen peroxide up to 500 μM did not alter viability or cell mechanics, suggesting that the particle effects are unlikely to be mediated by particle-generated reactive oxygen species. Our results highlight the susceptibility of cellular mechanical function to particulate exposures and suggest that direct exposure of the airway smooth muscle cells to particulates may initiate or aggravate respiratory diseases. PMID:20356875

  3. Biomechanical effects of environmental and engineered particles on human airway smooth muscle cells.

    PubMed

    Berntsen, P; Park, C Y; Rothen-Rutishauser, B; Tsuda, A; Sager, T M; Molina, R M; Donaghey, T C; Alencar, A M; Kasahara, D I; Ericsson, T; Millet, E J; Swenson, J; Tschumperlin, D J; Butler, J P; Brain, J D; Fredberg, J J; Gehr, P; Zhou, E H

    2010-06-01

    The past decade has seen significant increases in combustion-generated ambient particles, which contain a nanosized fraction (less than 100 nm), and even greater increases have occurred in engineered nanoparticles (NPs) propelled by the booming nanotechnology industry. Although inhalation of these particulates has become a public health concern, human health effects and mechanisms of action for NPs are not well understood. Focusing on the human airway smooth muscle cell, here we show that the cellular mechanical function is altered by particulate exposure in a manner that is dependent upon particle material, size and dose. We used Alamar Blue assay to measure cell viability and optical magnetic twisting cytometry to measure cell stiffness and agonist-induced contractility. The eight particle species fell into four categories, based on their respective effect on cell viability and on mechanical function. Cell viability was impaired and cell contractility was decreased by (i) zinc oxide (40-100 nm and less than 44 microm) and copper(II) oxide (less than 50 nm); cell contractility was decreased by (ii) fluorescent polystyrene spheres (40 nm), increased by (iii) welding fumes and unchanged by (iv) diesel exhaust particles, titanium dioxide (25 nm) and copper(II) oxide (less than 5 microm), although in none of these cases was cell viability impaired. Treatment with hydrogen peroxide up to 500 microM did not alter viability or cell mechanics, suggesting that the particle effects are unlikely to be mediated by particle-generated reactive oxygen species. Our results highlight the susceptibility of cellular mechanical function to particulate exposures and suggest that direct exposure of the airway smooth muscle cells to particulates may initiate or aggravate respiratory diseases. PMID:20356875

  4. Review of the facile (F/sub N/) method in particle transport theory

    SciTech Connect

    Garcia, R.D.M.

    1985-10-01

    The facile (F/sub N/) method for solving particle transport problems is reviewed. The fundamentals of the method are summarized, recent developments are discussed and several applications of the method are described in detail.

  5. Invited Review. Combustion instability in spray-guided stratified-charge engines. A review

    SciTech Connect

    Fansler, Todd D.; Reuss, D. L.; Sick, V.; Dahms, R. N.

    2015-02-02

    Our article reviews systematic research on combustion instabilities (principally rare, random misfires and partial burns) in spray-guided stratified-charge (SGSC) engines operated at part load with highly stratified fuel -air -residual mixtures. Results from high-speed optical imaging diagnostics and numerical simulation provide a conceptual framework and quantify the sensitivity of ignition and flame propagation to strong, cyclically varying temporal and spatial gradients in the flow field and in the fuel -air -residual distribution. For SGSC engines using multi-hole injectors, spark stretching and locally rich ignition are beneficial. Moreover, combustion instability is dominated by convective flow fluctuations that impede motion of the spark or flame kernel toward the bulk of the fuel, coupled with low flame speeds due to locally lean mixtures surrounding the kernel. In SGSC engines using outwardly opening piezo-electric injectors, ignition and early flame growth are strongly influenced by the spray's characteristic recirculation vortex. For both injection systems, the spray and the intake/compression-generated flow field influence each other. Factors underlying the benefits of multi-pulse injection are identified. Finally, some unresolved questions include (1) the extent to which piezo-SGSC misfires are caused by failure to form a flame kernel rather than by flame-kernel extinction (as in multi-hole SGSC engines); (2) the relative contributions of partially premixed flame propagation and mixing-controlled combustion under the exceptionally late-injection conditions that permit SGSC operation on E85-like fuels with very low NOx and soot emissions; and (3) the effects of flow-field variability on later combustion, where fuel-air-residual mixing within the piston bowl becomes important.

  6. Invited Review. Combustion instability in spray-guided stratified-charge engines. A review

    DOE PAGESBeta

    Fansler, Todd D.; Reuss, D. L.; Sick, V.; Dahms, R. N.

    2015-02-02

    Our article reviews systematic research on combustion instabilities (principally rare, random misfires and partial burns) in spray-guided stratified-charge (SGSC) engines operated at part load with highly stratified fuel -air -residual mixtures. Results from high-speed optical imaging diagnostics and numerical simulation provide a conceptual framework and quantify the sensitivity of ignition and flame propagation to strong, cyclically varying temporal and spatial gradients in the flow field and in the fuel -air -residual distribution. For SGSC engines using multi-hole injectors, spark stretching and locally rich ignition are beneficial. Moreover, combustion instability is dominated by convective flow fluctuations that impede motion of themore » spark or flame kernel toward the bulk of the fuel, coupled with low flame speeds due to locally lean mixtures surrounding the kernel. In SGSC engines using outwardly opening piezo-electric injectors, ignition and early flame growth are strongly influenced by the spray's characteristic recirculation vortex. For both injection systems, the spray and the intake/compression-generated flow field influence each other. Factors underlying the benefits of multi-pulse injection are identified. Finally, some unresolved questions include (1) the extent to which piezo-SGSC misfires are caused by failure to form a flame kernel rather than by flame-kernel extinction (as in multi-hole SGSC engines); (2) the relative contributions of partially premixed flame propagation and mixing-controlled combustion under the exceptionally late-injection conditions that permit SGSC operation on E85-like fuels with very low NOx and soot emissions; and (3) the effects of flow-field variability on later combustion, where fuel-air-residual mixing within the piston bowl becomes important.« less

  7. Calcium phosphate ceramic systems in growth factor and drug delivery for bone tissue engineering: A review

    PubMed Central

    Bose, Susmita; Tarafder, Solaiman

    2012-01-01

    Calcium phosphates (CaPs) are the most widely used bone substitutes in bone tissue engineering due to their compositional similarities to bone mineral and excellent biocompatibility. In recent years, CaPs, especially hydroxyapatite and tricalcium phosphate, have attracted significant interest in simultaneous use as bone substitute and drug delivery vehicle, adding a new dimension to their application. CaPs are more biocompatible than many other ceramic and inorganic nanoparticles. Their biocompatibility and variable stoichiometry, thus surface charge density, functionality, and dissolution properties, make them suitable for both drug and growth factor delivery. CaP matrices and scaffolds have been reported to act as delivery vehicles for growth factors and drugs in bone tissue engineering. Local drug delivery in musculoskeletal disorder treatments can address some of the critical issues more effectively and efficiently than the systemic delivery. CaPs are used as coatings on metallic implants, CaP cements, and custom designed scaffolds to treat musculoskeletal disorders. This review highlights some of the current drug and growth factor delivery approaches and critical issues using CaP particles, coatings, cements, and scaffolds towards orthopedic and dental applications. PMID:22127225

  8. Chemical Composition of Aerosol Particles Emitted by a Passenger Car Engine Fueled by Ethanol/Gasoline Mixtures

    NASA Astrophysics Data System (ADS)

    Medrano, J. M.; Gross, D. S.; Dutcher, D. D.; Drayton, M.; Kittelson, D.; McMurry, P.

    2007-12-01

    With concerns of national security, climate change, and human health, many people have called for oil independence for the United States and for the creation of alternative fuels. Ethanol has been widely praised as a viable alternative to petroleum-based fuels, due to the fact that it can be produced locally. A great deal of work has been done to characterize the energy balance of ethanol production versus consumption, but there have been fewer studies of the environmental and health impacts of emissions from combustion of ethanol/gasoline mixtures such as those burned in the modern vehicle fleet. To study the particulate emissions from such fuels, different ethanol/gasoline fuel mixtures with 0, 20, 40, and 85% ethanol were burned in a dynamometer-mounted automobile engine. The engine exhaust was diluted and sampled with two aerosol Time-of-Flight Mass Spectrometers (TSI 3800 ATOFMS), sampling different particle size ranges (50-500 nm and 150-3000 nm, respectively), to measure size and composition of the emitted aerosol particles. A variety of other aerosol characterization techniques were also employed to determine the size distribution of the aerosol particles, the mass emission rate from the engine, and the concentration of polycyclic aromatic hydrocarbons (PAHs) and elemental carbon (EC) in the particle emissions. Here we will focus on results from the ATOFMS, which provides us with a particle size and mass spectra - for both negative and positive ions - for each particle that is sampled. Particles being emitted were found to contain primarily PAHs, elemental carbon (EC), nitrates, and sulfates. Particles were analyzed to investigate trends in particle composition as a function of fuel ethanol content, particle size, and for the types of particles emitted. A trend in particle type as a function of fuel ethanol content was evident in smaller particles, and trends in composition as a function of particle size were visible across the entire size range sampled.

  9. The use of particle acceleration machines in radiotherapy: A review

    NASA Astrophysics Data System (ADS)

    Bosio, C.; Pelliccioni, M.

    1982-10-01

    The effects of the dosage and the oxygen enhancement ratio when using particle accelerators in radiotherapy are discussed. The advantages derived from the Bragg peak effect and pion mass to energy conversion are commented on. Machines to produce electrons, X rays, protons, neutrons, heavy ions and negative pions are described. The good results observed in the case of negative pions can be attributed either to the favorable dose distribution or to the specific biological properties of the particles produced in the process of pion capture. The cost factors of the generating machines are also discussed.

  10. A review of electron bombardment thruster systems/spacecraft field and particle interfaces

    NASA Technical Reports Server (NTRS)

    Byers, D. C.

    1978-01-01

    Information on the field and particle interfaces of electron bombardment ion thruster systems was summarized. Major areas discussed were the nonpropellant particles, neutral propellant, ion beam, low energy plasma, and fields. Spacecraft functions and subsystems reviewed were solar arrays, thermal control systems, optical sensors, communications, science, structures and materials, and potential control.

  11. Review: Particle number size distributions from seven major sources and implications for source apportionment studies

    NASA Astrophysics Data System (ADS)

    Vu, Tuan V.; Delgado-Saborit, Juana Maria; Harrison, Roy M.

    2015-12-01

    The particle number size distribution (PNSD) of airborne particles not only provides us with information about sources and atmospheric processing of particles, but also plays an important role in determining regional lung dose. As a result, urban particles and their size distributions have received much attention with a rapid increase of publications in recent years. The object of this review is to synthesise and analyse existing knowledge on particles in urban environments with a focus on their number concentration and size distribution. This study briefly reviews the characterization of PNSD from seven major sources of urban particles including traffic emissions, industrial emissions, biomass burning, cooking, transported aerosol, marine aerosol and nucleation. It then discusses atmospheric physical processes such as coagulation or condensation which have a strong influence on PNSD. Finally, the implications of PNSD datasets for source modelling are briefly discussed. Based on this review, it is concluded that the concentrations, modal structures and temporal patterns of urban particles are strongly influenced by traffic emissions, which are identified as the main source of particle number in urban environments. Information derived from particle number size distributions is beginning to play an important role in source apportionment studies.

  12. BIOLOGICAL EFFECTS OF UTAH VALLEY PARTICLES: A REVIEW

    EPA Science Inventory

    The Utah Valley provided a unique opportunity to evaluate the health effects of particulate matter (PM) in humans. The area has had intermittently high particle levels with the principal point source being a steel mill. Due to a labor dispute, the mill was shut down. The closu...

  13. Applying Peer Reviews in Software Engineering Education: An Experiment and Lessons Learned

    ERIC Educational Resources Information Center

    Garousi, V.

    2010-01-01

    Based on the demonstrated value of peer reviews in the engineering industry, numerous industry experts have listed it at the top of the list of desirable development practices. Experience has shown that problems (defects) are eliminated earlier if a development process incorporates peer reviews and that these reviews are as effective as or even…

  14. Metal particle emissions in the exhaust stream of diesel engines: an electron microscope study.

    PubMed

    Liati, Anthi; Schreiber, Daniel; Dimopoulos Eggenschwiler, Panayotis; Arroyo Rojas Dasilva, Yadira

    2013-12-17

    Scanning electron microscopy and transmission electron microscopy were applied to investigate the morphology, mode of occurrence and chemical composition of metal particles (diesel ash) in the exhaust stream of a small truck outfitted with a typical after-treatment system (a diesel oxidation catalyst (DOC) and a downstream diesel particulate filter (DPF)). Ash consists of Ca-Zn-P-Mg-S-Na-Al-K-phases (lube-oil related), Fe, Cr, Ni, Sn, Pb, Sn (engine wear), and Pd (DOC coating). Soot agglomerates of variable sizes (<0.5-5 μm) are abundant upstream of the DPF and are ash-free or contain notably little attached ash. Post-DPF soot agglomerates are very few, typically large (>1-5 μm, exceptionally 13 μm), rarely <0.5 μm, and contain abundant ash carried mostly from inside the DPF. The ash that reaches the atmosphere also occurs as separate aggregates ca. 0.2-2 μm in size consisting of sintered primary phases, ca. 20-400 nm large. Insoluble particles of these sizes may harm the respiratory and cardiovascular systems. The DPF probably promotes breakout of large soot agglomerates (mostly ash-bearing) by favoring sintering. Noble metals detached from the DOC coating may reach the ambient air. Finally, very few agglomerates of Fe-oxide nanoparticles form newly from engine wear and escape into the atmosphere. PMID:24274188

  15. Effects of biodiesel, engine load and diesel particulate filter on nonvolatile particle number size distributions in heavy-duty diesel engine exhaust.

    PubMed

    Young, Li-Hao; Liou, Yi-Jyun; Cheng, Man-Ting; Lu, Jau-Huai; Yang, Hsi-Hsien; Tsai, Ying I; Wang, Lin-Chi; Chen, Chung-Bang; Lai, Jim-Shoung

    2012-01-15

    Diesel engine exhaust contains large numbers of submicrometer particles that degrade air quality and human health. This study examines the number emission characteristics of 10-1000 nm nonvolatile particles from a heavy-duty diesel engine, operating with various waste cooking oil biodiesel blends (B2, B10 and B20), engine loads (0%, 25%, 50% and 75%) and a diesel oxidation catalyst plus diesel particulate filter (DOC+DPF) under steady modes. For a given load, the total particle number concentrations (N(TOT)) decrease slightly, while the mode diameters show negligible changes with increasing biodiesel blends. For a given biodiesel blend, both the N(TOT) and mode diameters increase modestly with increasing load of above 25%. The N(TOT) at idle are highest and their size distributions are strongly affected by condensation and possible nucleation of semivolatile materials. Nonvolatile cores of diameters less than 16 nm are only observed at idle mode. The DOC+DPF shows remarkable filtration efficiency for both the core and soot particles, irrespective of the biodiesel blend and engine load under study. The N(TOT) post the DOC+DPF are comparable to typical ambient levels of ≈ 10(4)cm(-3). This implies that, without concurrent reductions of semivolatile materials, the formation of semivolatile nucleation mode particles post the after treatment is highly favored. PMID:22119306

  16. A Review of Discrete Element Method (DEM) Particle Shapes and Size Distributions for Lunar Soil

    NASA Technical Reports Server (NTRS)

    Lane, John E.; Metzger, Philip T.; Wilkinson, R. Allen

    2010-01-01

    As part of ongoing efforts to develop models of lunar soil mechanics, this report reviews two topics that are important to discrete element method (DEM) modeling the behavior of soils (such as lunar soils): (1) methods of modeling particle shapes and (2) analytical representations of particle size distribution. The choice of particle shape complexity is driven primarily by opposing tradeoffs with total number of particles, computer memory, and total simulation computer processing time. The choice is also dependent on available DEM software capabilities. For example, PFC2D/PFC3D and EDEM support clustering of spheres; MIMES incorporates superquadric particle shapes; and BLOKS3D provides polyhedra shapes. Most commercial and custom DEM software supports some type of complex particle shape beyond the standard sphere. Convex polyhedra, clusters of spheres and single parametric particle shapes such as the ellipsoid, polyellipsoid, and superquadric, are all motivated by the desire to introduce asymmetry into the particle shape, as well as edges and corners, in order to better simulate actual granular particle shapes and behavior. An empirical particle size distribution (PSD) formula is shown to fit desert sand data from Bagnold. Particle size data of JSC-1a obtained from a fine particle analyzer at the NASA Kennedy Space Center is also fitted to a similar empirical PSD function.

  17. Review of AIDS development. [airborne computers for reliability engineering

    NASA Technical Reports Server (NTRS)

    Vermeulen, H. C.; Danielsson, S. G.

    1981-01-01

    The operation and implementation of the aircraft integrated data system AIDS are described. The system is described as an engineering tool with strong emphasis on analysis of recorded information. The AIDS is primarily directed to the monitoring of parameters related to: the safety of the flight; the performance of the aircraft; the performance of the flight guidance system; and the performance and condition of the engines. The system provide short term trend analysis on a trend chart that is updated by the flight engineer on every flight that lasts more than 4 flight hours. Engine data prints are automatically presented during take-off and in the case of limit excedance, e.g., the print shows an automatically reported impending hotstarts on engine nr. 1. Other significant features are reported.

  18. Diesel particle filter and fuel effects on heavy-duty diesel engine emissions.

    PubMed

    Ratcliff, Matthew A; Dane, A John; Williams, Aaron; Ireland, John; Luecke, Jon; McCormick, Robert L; Voorhees, Kent J

    2010-11-01

    The impacts of biodiesel and a continuously regenerated (catalyzed) diesel particle filter (DPF) on the emissions of volatile unburned hydrocarbons, carbonyls, and particle associated polycyclic aromatic hydrocarbons (PAH) and nitro-PAH, were investigated. Experiments were conducted on a 5.9 L Cummins ISB, heavy-duty diesel engine using certification ultra-low-sulfur diesel (ULSD, S ≤ 15 ppm), soy biodiesel (B100), and a 20% blend thereof (B20). Against the ULSD baseline, B20 and B100 reduced engine-out emissions of measured unburned volatile hydrocarbons and PM associated PAH and nitro-PAH by significant percentages (40% or more for B20 and higher percentage for B100). However, emissions of benzene were unaffected by the presence of biodiesel and emissions of naphthalene actually increased for B100. This suggests that the unsaturated FAME in soy-biodiesel can react to form aromatic rings in the diesel combustion environment. Methyl acrylate and methyl 3-butanoate were observed as significant species in the exhaust for B20 and B100 and may serve as markers of the presence of biodiesel in the fuel. The DPF was highly effective at converting gaseous hydrocarbons and PM associated PAH and total nitro-PAH. However, conversion of 1-nitropyrene by the DPF was less than 50% for all fuels. Blending of biodiesel caused a slight reduction in engine-out emissions of acrolein, but otherwise had little effect on carbonyl emissions. The DPF was highly effective for conversion of carbonyls, with the exception of formaldehyde. Formaldehyde emissions were increased by the DPF for ULSD and B20. PMID:20886845

  19. Fine particle and organic vapor emissions from staged tests of an in-use aircraft engine

    NASA Astrophysics Data System (ADS)

    Presto, Albert A.; Nguyen, Ngoc T.; Ranjan, Manish; Reeder, Aaron J.; Lipsky, Eric M.; Hennigan, Christopher J.; Miracolo, Marissa A.; Riemer, Daniel D.; Robinson, Allen L.

    2011-07-01

    Staged tests were conducted to measure the particle and vapor emissions from a CFM56-2B1 gas-turbine engine mounted on a KC-135T Stratotanker airframe at different engine loads. Exhaust was sampled using a rake inlet installed 1-m downstream of the engine exit plane of a parked and chocked aircraft and a dilution sampler and portable smog chamber were used to investigate the particulate matter (PM) emissions. Total fine PM mass emissions were highest at low (4%) and high (85%) load and lower at intermediate loads (7% and 30%). PM mass emissions at 4% load are dominated by organics, while at 85% load elemental carbon is dominant. Quantifying the primary organic aerosol (POA) emissions is complicated by substantial filter sampling artifacts. Partitioning experiments reveal that the majority of the POA is semivolatile; for example, the POA emission factor changed by a factor of two when the background organic aerosol concentration was increased from 0.7 to 4 μg m -3. Therefore, one cannot define a single non-volatile PM emission factor for aircraft exhaust. The gas- and particle-phase organic emissions were comprehensively characterized by analyzing canister, sorbent and filter samples with gas-chromatography/mass-spectrometry. Vapor-phase organic emissions are highest at 4% load and decrease with increasing load. Low-volatility organics (less volatile than a C 12n-alkane) contributed 10-20% of the total organic emissions. The low-volatility organic emissions contain signatures of unburned fuel and aircraft lubricating oil but are dominated by an unresolved complex mixture (UCM) of presumably branched and cyclic alkanes. Emissions at all loads contain more low-volatility organic vapors than POA; thus secondary organic aerosol formation in the aging plume will likely exceed POA emissions.

  20. Detection of very large ions in aircraft gas turbine engine combustor exhaust: charged small soot particles?

    NASA Astrophysics Data System (ADS)

    Wilhelm, S.; Haverkamp, H.; Sorokin, A.; Arnold, F.

    Small electrically charged soot particles (CSP) present in the exhaust of a jet aircraft engine combustor have been detected by a Large Ion Mass Spectrometer and quantitatively measured by an Ion Mobility Analyzer. The size and concentration measurements which took place at an aircraft gas-turbine engine combustor test-rig at the ground covered different combustor conditions (fuel flow=FF, fuel sulphur content=FSC). At the high-pressure turbine stage of the engine, CSP-diameters were mostly around 6 nm and CSP-concentrations reached up to 4.8×10 7 cm -3 (positive and negative) corresponding to a CSP-emission index ECSP=2.5×10 15 CSP kg -1 fuel burnt. The ECSP increased with FF but did not increase with FSC. The latter indicates that sulphur was not a major component of the large ions. Possible CSP-sources and CSP-sinks as well as CSP-roles are discussed.

  1. Particle path tracking method in two- and three-dimensional continuously rotating detonation engines

    NASA Astrophysics Data System (ADS)

    Zhou, Rui; Wu, Dan; Liu, Yan; Wang, Jian-Ping

    2014-12-01

    The particle path tracking method is proposed and used in two-dimensional (2D) and three-dimensional (3D) numerical simulations of continuously rotating detonation engines (CRDEs). This method is used to analyze the combustion and expansion processes of the fresh particles, and the thermodynamic cycle process of CRDE. In a 3D CRDE flow field, as the radius of the annulus increases, the no-injection area proportion increases, the non-detonation proportion decreases, and the detonation height decreases. The flow field parameters on the 3D mid annulus are different from in the 2D flow field under the same chamber size. The non-detonation proportion in the 3D flow field is less than in the 2D flow field. In the 2D and 3D CRDE, the paths of the flow particles have only a small fluctuation in the circumferential direction. The numerical thermodynamic cycle processes are qualitatively consistent with the three ideal cycle models, and they are right in between the ideal F—J cycle and ideal ZND cycle. The net mechanical work and thermal efficiency are slightly smaller in the 2D simulation than in the 3D simulation. In the 3D CRDE, as the radius of the annulus increases, the net mechanical work is almost constant, and the thermal efficiency increases. The numerical thermal efficiencies are larger than F—J cycle, and much smaller than ZND cycle.

  2. Inflammation-Related Effects of Diesel Engine Exhaust Particles: Studies on Lung Cells In Vitro

    PubMed Central

    Schwarze, P. E.; Totlandsdal, A. I.; Låg, M.; Refsnes, M.; Holme, J. A.; Øvrevik, J.

    2013-01-01

    Diesel exhaust and its particles (DEP) have been under scrutiny for health effects in humans. In the development of these effects inflammation is regarded as a key process. Overall, in vitro studies report similar DEP-induced changes in markers of inflammation, including cytokines and chemokines, as studies in vivo. In vitro studies suggest that soluble extracts of DEP have the greatest impact on the expression and release of proinflammatory markers. Main DEP mediators of effects have still not been identified and are difficult to find, as fuel and engine technology developments lead to continuously altered characteristics of emissions. Involved mechanisms remain somewhat unclear. DEP extracts appear to comprise components that are able to activate various membrane and cytosolic receptors. Through interactions with receptors, ion channels, and phosphorylation enzymes, molecules in the particle extract will trigger various cell signaling pathways that may lead to the release of inflammatory markers directly or indirectly by causing cell death. In vitro studies represent a fast and convenient system which may have implications for technology development. Furthermore, knowledge regarding how particles elicit their effects may contribute to understanding of DEP-induced health effects in vivo, with possible implications for identifying susceptible groups of people and effect biomarkers. PMID:23509760

  3. BOOK REVIEW: Physics for Scientists and Engineers Third Edition

    NASA Astrophysics Data System (ADS)

    Giancoli, Douglas C.

    2000-09-01

    There are a large number of textbooks for the college and university student produced in the USA and here is one that I had not seen before even though it is now in the third edition. But it is so similar to many others. The standard version as reviewed here covers the usual topics of classical physics, namely kinematics, energy, waves and oscillations, thermodynamics, electricity and magnetism and light. Also, as is usual with the American coverage, it includes fluids, special relativity and a short chapter on quantum theory and the atom. An extended version is available covering modern physics, astrophysics and cosmology. There is also available back-up material such as instructor's manual, CD-ROM, video and other extra teaching material Full colour is used and the book is lavishly illustrated with diagrams and photographs. Calculus is used throughout the book, although this is limited to basic differentiation and integration. There is an extensive range of worked examples plus end-of-chapter questions and problems, with numerical answers given to the odd-numbered problems. The physics is illustrated with many everyday examples. The styles of course presentation and hence the styles of book used in the USA and the UK seem to be diverging. It is unlikely such a book as this would be used at A-level. This is not only because of the calculus, albeit simple, but because of the detailed coverage of classical topics. Increasingly there has been a trend in this country to be more selective in content, and yet at the same time to incorporate more modern topics such as solids, environmental and atmospheric physics, particle physics and cosmology, but described in a fairly elementary way. The book would be suitable for preliminary year and first-year university physics courses but its size and weight are daunting. I am not sure why physics described in such an encyclopaedic way is popular in the US but less so here. However, of its type this book is both attractive and

  4. Support vector machine to predict diesel engine performance and emission parameters fueled with nano-particles additive to diesel fuel

    NASA Astrophysics Data System (ADS)

    Ghanbari, M.; Najafi, G.; Ghobadian, B.; Mamat, R.; Noor, M. M.; Moosavian, A.

    2015-12-01

    This paper studies the use of adaptive Support Vector Machine (SVM) to predict the performance parameters and exhaust emissions of a diesel engine operating on nanodiesel blended fuels. In order to predict the engine parameters, the whole experimental data were randomly divided into training and testing data. For SVM modelling, different values for radial basis function (RBF) kernel width and penalty parameters (C) were considered and the optimum values were then found. The results demonstrate that SVM is capable of predicting the diesel engine performance and emissions. In the experimental step, Carbon nano tubes (CNT) (40, 80 and 120 ppm) and nano silver particles (40, 80 and 120 ppm) with nanostructure were prepared and added as additive to the diesel fuel. Six cylinders, four-stroke diesel engine was fuelled with these new blended fuels and operated at different engine speeds. Experimental test results indicated the fact that adding nano particles to diesel fuel, increased diesel engine power and torque output. For nano-diesel it was found that the brake specific fuel consumption (bsfc) was decreased compared to the net diesel fuel. The results proved that with increase of nano particles concentrations (from 40 ppm to 120 ppm) in diesel fuel, CO2 emission increased. CO emission in diesel fuel with nano-particles was lower significantly compared to pure diesel fuel. UHC emission with silver nano-diesel blended fuel decreased while with fuels that contains CNT nano particles increased. The trend of NOx emission was inverse compared to the UHC emission. With adding nano particles to the blended fuels, NOx increased compared to the net diesel fuel. The tests revealed that silver & CNT nano particles can be used as additive in diesel fuel to improve complete combustion of the fuel and reduce the exhaust emissions significantly.

  5. [Book review] Green engineering: environmentally conscious design, by David T. Allen and David R. Shonnard

    USGS Publications Warehouse

    Boustany, R.G.

    2002-01-01

    Review of: Green engineering: Environmentally conscious design / David T. Allen and David R. Shonnard / Prentice-Hall, Inc., One Lake Street, Upper Saddle River, NJ 07458. 2002. 552 pages. ISBN 0-13-061908-6.

  6. A review of the behaviour and engineering properties of carbonate soils

    NASA Astrophysics Data System (ADS)

    Poulos, H. G.

    1980-12-01

    The nature and origins of carbonate soil deposits are reviewed and methods of classifying such soils are discussed. Data on their engineering behavior is then presented, including shear strength properties, compressibility and consolidation characteristics, and their response to cyclic loading.

  7. Automotive Stirling Engine Mod 1 Design Review, volume 2

    NASA Technical Reports Server (NTRS)

    1982-01-01

    The auxiliaries and the control system for the ASE MOD I: (1) provide the required fuel and air flows for a well controlled combustion process, generating heat to the Stirling cycle; (2) provide a driver acceptable method for controlling the power output of the engine; (3) provide adequate lubrication and cooling water circulation; (4) generate the electric energy required for engine and vehicle operation; (5) provide a driver acceptable method for starting, stopping and monitoring the engine; and (6) provide a guard system, that protects the engine at component or system malfunction. The control principles and the way the different components and sub-systems interact are described as well as the different auxiliaries, the air fuel system, the power control systems and the electronics. The arrangement and location of auxiliaries and other major components are also examined.

  8. NASA-universities relationships in aero/space engineering: A review of NASA's program

    NASA Technical Reports Server (NTRS)

    1985-01-01

    NASA is concerned about the health of aerospace engineering departments at U.S. universities. The number of advanced degrees in aerospace engineering has declined. There is concern that universities' facilities, research equipment, and instrumentation may be aging or outmoded and therefore affect the quality of research and education. NASA requested that the National Research Council's Aeronautics and Space Engineering Board (ASEB) review NASA's support of universities and make recommendations to improve the program's effectiveness.

  9. Acute toxicity of virgin and used engine oil enriched with copper nano particles in the earthworm

    NASA Astrophysics Data System (ADS)

    Khodabandeh, M.; Koohi, M. K.; Roshani, A.; Shahroziyan, E.; Badri, B.; Pourfallah, A.; Shams, Gh; Hobbenaghi, R.; Sadeghi-Hashjin, G.

    2011-07-01

    In spite of development of nanotechnology and creation of new opportunities for industry, new applications and products initiated by this technology may cause harmful effects on human health and environment. Unfortunately, there is no sufficient information on the harmful effects caused by application of some nano materials; the current knowledge in this field is limited solely to the nano particles but not the final products. Nano cupper particles, as one of the common materials produced in industrial scale is widely used as additives into engine oil to reduce friction and improve lubrication. However, the difference between the effects of virgin and used conventional engine oil (CEO) and the engine oil containing cupper nano particles (NEO) on the environment is not known. Earthworm, as a one of the species which could live and survive in different sorts of earth and has a certain role in protecting the soil structure and fertility, was used in this experiment. In accordance with the recommended method of OECD.1984, Filter Paper test in 24 and 48 h based on 8 concentrations in the range of 3×10-3 - 24×10-3 ml/cm2 and Artificial Soil test in 7 and 14 days based on 7 concentrations in the range of 0.1 mg/kg - 100 g/kg were carried out to study earthworms in terms of lifetime (LC50), morphology and pathology. It was shown that the 48 h LC50 for virgin CEO, virgin NEO, used CEO(8000 km) and used NEO (8000 km) were 6×10-3, 23×10-3, 24×10-3 and 16×10-3 ml/cm2 respectively. Furthermore, 14-day LC50 in artificial soil for all cases were above 100 g/kg. It is concluded that virgin CEO is more toxic than virgin NEO. Meanwhile, the CEO shows significant reduction in toxicity after consumption and the used NEO shows more toxicity in comparison to virgin product. It seems that more investigations on the effects of final products specifically after consumption is necessary because the products after consumption have the most contact with environment and subsequently

  10. Engineering particle morphology and assembly for proton conducting fuel cell membrane applications

    NASA Astrophysics Data System (ADS)

    Liu, Dongxia

    The development of high performance ion conducting membranes is crucial to the commercialization of polymer electrolyte membrane fuel cells (PEMFCs) and solid oxide fuel cells (SOFCs). This thesis work addresses some of the issues for improving the performance of ion conducting membranes in PEMFCs and SOFCs through engineering membrane microstructures. Electric-field directed particle assembly shows promise as a route to control the structure of polymer composite membranes in PEMFCs. The application of electric fields results in the aggregation of proton conducting particles into particle chains spanning the thickness of composite membranes. The field-induced structure provides improved proton conductivity, selectivity for protons over methanol, and mechanical stability compared to membranes processed without electric field. Hydrothermal deposition is developed as a route to grow electrolyte crystals into membranes (material is hydroxyapatite) with aligned proton conductive pathways that significantly enhance proton transport by eliminating grain boundary resistance. By varying deposition parameters such as reactant concentration, reaction time, or adding crystal growth modifiers, dense hydroxyapatite electrolyte membranes with a range of thickness are produced. The microstructurally engineered hydroxyapatite membranes are promising electrolyte candidates for intermediate temperature fuel cells. The microstructural engineering of ceramics by hydrothermal deposition can potentially be applied to create other ion conducting materials with optimized transport properties. To understand how to control the crystal growth habit by adding growth modifiers, growth of unusual calcite rods was investigated in a microemulsion-based synthesis prior to the investigation of hydrothermal deposition of hydroxyapatite membranes. The microemulsions act as crystal growth modifier to mediate crystal nucleation and subsequent growth. The small microemulsion droplets confine nucleation

  11. The Use of Motivation Theory in Engineering Education Research: A Systematic Review of Literature

    ERIC Educational Resources Information Center

    Brown, Philip R.; McCord, Rachel E.; Matusovich, Holly M.; Kajfez, Rachel L.

    2015-01-01

    Motivation is frequently studied in the context of engineering education. However, the use of the term motivation can be inconsistent, both in how clearly it is defined and in how it is implemented in research designs and practice. This systematic literature review investigates the use of motivation across recent engineering education…

  12. 76 FR 55389 - Federal Acquisition Regulation; Submission for OMB Review; Architect-Engineer Qualifications (SF...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-07

    ... Register at 76 FR 20351, on April 12, 2011. One comment was received. General Comment A respondent... Regulation; Submission for OMB Review; Architect-Engineer Qualifications (SF 330) AGENCIES: Department of... Architect-Engineer Qualifications form (SF 330). Public comments are particularly invited on: Whether...

  13. AUTOMOTIVE DIESEL MAINTENANCE 1. UNIT XXIX, REVIEWING THE CONSTRUCTION OF ENGINE COMPONENTS.

    ERIC Educational Resources Information Center

    Human Engineering Inst., Cleveland, OH.

    THIS MODULE OF A 30-MODULE COURSE IS DESIGNED TO PROVIDE A REVIEW OF THE CONSTRUCTION AND OPERATION OF DIESEL ENGINE COMPONENTS. TOPICS ARE STATIONARY PARTS, ENGINE MOVING PARTS, PISTON RINGS, AND CONNECTING RODS AND PISTON PINS. THE MODULE CONSISTS OF AN INSTRUCTOR'S GUIDE, TRANSPARENCIES, A LIST OF SUGGESTED SUPPLEMENTARY MATERIALS, AND TRAINEE…

  14. First exit times of harmonically trapped particles: a didactic review

    NASA Astrophysics Data System (ADS)

    Grebenkov, Denis S.

    2015-01-01

    We revise the classical problem of characterizing first exit times of a harmonically trapped particle whose motion is described by a one- or multidimensional Ornstein-Uhlenbeck process. We start by recalling the main derivation steps of a propagator using Langevin and Fokker-Planck equations. The mean exit time, the moment-generating function and the survival probability are then expressed through confluent hypergeometric functions and thoroughly analyzed. We also present a rapidly converging series representation of confluent hypergeometric functions that is particularly well suited for numerical computation of eigenvalues and eigenfunctions of the governing Fokker-Planck operator. We discuss several applications of first exit times, such as the detection of time intervals during which motor proteins exert a constant force onto a tracer in optical tweezers single-particle tracking experiments; adhesion bond dissociation under mechanical stress; characterization of active periods of trend-following and mean-reverting strategies in algorithmic trading on stock markets; relation to the distribution of first crossing times of a moving boundary by Brownian motion. Some extensions are described, including diffusion under quadratic double-well potential and anomalous diffusion.

  15. Effects of Particle Filters and Accelerated Engine Replacement on Heavy-Duty Diesel Vehicle Emissions of Black Carbon, Nitrogen Oxides, and Ultrafine Particles

    NASA Astrophysics Data System (ADS)

    Kirchstetter, T.; Preble, C.; Dallmann, T. R.; DeMartini, S. J.; Tang, N. W.; Kreisberg, N. M.; Hering, S. V.; Harley, R. A.

    2013-12-01

    Diesel particle filters have become widely used in the United States since the introduction in 2007 of a more stringent exhaust particulate matter emission standard for new heavy-duty diesel vehicle engines. California has instituted additional regulations requiring retrofit or replacement of older in-use engines to accelerate emission reductions and air quality improvements. This presentation summarizes pollutant emission changes measured over several field campaigns at the Port of Oakland in the San Francisco Bay Area associated with diesel particulate filter use and accelerated modernization of the heavy-duty truck fleet. Pollutants in the exhaust plumes of hundreds of heavy-duty trucks en route to the Port were measured in 2009, 2010, 2011, and 2013. Ultrafine particle number, black carbon (BC), nitrogen oxides (NOx), and nitrogen dioxide (NO2) concentrations were measured at a frequency ≤ 1 Hz and normalized to measured carbon dioxide concentrations to quantify fuel-based emission factors (grams of pollutant emitted per kilogram of diesel consumed). The size distribution of particles in truck exhaust plumes was also measured at 1 Hz. In the two most recent campaigns, emissions were linked on a truck-by-truck basis to installed emission control equipment via the matching of transcribed license plates to a Port truck database. Accelerated replacement of older engines with newer engines and retrofit of trucks with diesel particle filters reduced fleet-average emissions of BC and NOx. Preliminary results from the two most recent field campaigns indicate that trucks without diesel particle filters emit 4 times more BC than filter-equipped trucks. Diesel particle filters increase emissions of NO2, however, and filter-equipped trucks have NO2/NOx ratios that are 4 to 7 times greater than trucks without filters. Preliminary findings related to particle size distribution indicate that (a) most trucks emitted particles characterized by a single mode of approximately

  16. A Review of Engine Seal Performance and Requirements for Current and Future Army Engine Platforms

    NASA Technical Reports Server (NTRS)

    Delgado, Irebert R.; Proctor, Margaret P.

    2008-01-01

    Sand ingestion continues to impact combat ground and air vehicles in military operations in the Middle East. The T-700 engine used in Apache and Blackhawk helicopters has been subjected to increased overhauls due to sand and dust ingestion during desert operations. Engine component wear includes compressor and turbine blades/vanes resulting in decreased engine power and efficiency. Engine labyrinth seals have also been subjected to sand and dust erosion resulting in tooth tip wear, increased clearances, and loss in efficiency. For the current investigation, a brief overview is given of the history of the T-700 engine development with respect to sand and dust ingestion requirements. The operational condition of labyrinth seals taken out of service from 4 different locations of the T-700 engine during engine overhauls are examined. Collaborative efforts between the Army and NASA to improve turbine engine seal leakage and life capability are currently focused on noncontacting, low leakage, compliant designs. These new concepts should be evaluated for their tolerance to sand laden air. Future R&D efforts to improve seal erosion resistance and operation in desert environments are recommended

  17. Space vehicle engine and heat shield environment review. Volume 1: Engineering analysis

    NASA Technical Reports Server (NTRS)

    Mcanelly, W. B.; Young, C. T. K.

    1973-01-01

    Methods for predicting the base heating characteristics of a multiple rocket engine installation are discussed. The environmental data is applied to the design of adequate protection system for the engine components. The methods for predicting the base region thermal environment are categorized as: (1) scale model testing, (2) extrapolation of previous and related flight test results, and (3) semiempirical analytical techniques.

  18. Comprehensive Characterization Of Ultrafine Particulate Emission From 2007 Diesel Engines: PM Size Distribution, Loading And Indidividual Particle Size And Composition.

    NASA Astrophysics Data System (ADS)

    Zelenyuk, A.; Cuadra-Rodriguez, L. A.; Imre, D.; Shimpi, S.; Warey, A.

    2006-12-01

    The strong absorption of solar radiation by black carbon (BC) impacts the atmospheric radiative balance in a complex and significant manner. One of the most important sources of BC is vehicular emissions, of which diesel represents a significant fraction. To address this issue the EPA has issues new stringent regulations that will be in effect in 2007, limiting the amount of particulate mass that can be emitted by diesel engines. The new engines are equipped with aftertreatments that reduce PM emissions to the point, where filter measurements are subject to significant artifacts and characterization by other techniques presents new challenges. We will present the results of the multidisciplinary study conducted at the Cummins Technical Center in which a suite of instruments was deployed to yield comprehensive, temporally resolved information on the diesel exhaust particle loadings and properties in real-time: Particle size distributions were measured by Engine Exhaust Particle Sizer (EEPS) and Scanning Mobility Particle Sizer (SMPS). Total particle diameter concentration was obtained using Electrical Aerosol Detector (EAD). Laser Induced Incandescence and photoacoustic techniques were used to monitor the PM soot content. Single Particle Laser Ablation Time-of- flight Mass Spectrometer (SPLAT) provided the aerodynamic diameter and chemical composition of individual diesel exhaust particles. Measurements were conducted on a number of heavy duty diesel engines operated under variety of operating conditions, including FTP transient cycles, ramped-modal cycles and steady states runs. We have also characterized PM emissions during diesel particulate filter regeneration cycles. We will present a comparison of PM characteristics observed during identical cycles, but with and without the use of aftertreatment. A total of approximately 100,000 individual particles were sized and their composition characterized by SPLAT. The aerodynamic size distributions of the characterized

  19. Detection of Engineered Copper Nanoparticles in Soil Using Single Particle ICP-MS

    PubMed Central

    Navratilova, Jana; Praetorius, Antonia; Gondikas, Andreas; Fabienke, Willi; von der Kammer, Frank; Hofmann, Thilo

    2015-01-01

    Regulatory efforts rely on nanometrology for the development and implementation of laws regarding the incorporation of engineered nanomaterials (ENMs) into industrial and consumer products. Copper is currently one of the most common metals used in the constantly developing and expanding sector of nanotechnology. The use of copper nanoparticles in products, such as agricultural biocides, cosmetics and paints, is increasing. Copper based ENMs will eventually be released to the environment through the use and disposal of nano-enabled products, however, the detection of copper ENMs in environmental samples is a challenging task. Single particle inductively coupled plasma mass spectroscopy (spICP-MS) has been suggested as a powerful tool for routine nanometrology efforts. In this work, we apply a spICP-MS method for the detection of engineered copper nanomaterials in colloidal extracts from natural soil samples. Overall, copper nanoparticles were successfully detected in the soil colloidal extracts and the importance of dwell time, background removal, and sample dilution for method optimization and recovery maximization is highlighted. PMID:26690460

  20. Ultra Fine Particles from Diesel Engines Induce Vascular Oxidative Stress via JNK Activation

    PubMed Central

    Li, Rongsong; Ning, Zhi; Cui, Jeffery; Khalsa, Bhavraj; Ai, Lisong; Takabe, Wakako; Beebe, Tyler; Majumdar, Rohit; Sioutas, Constantinos; Hsiai, Tzung

    2011-01-01

    Exposure of particulate air pollution is linked to increased incidences of cardiovascular diseases. Ambient ultra fine particles (UFP) from diesel vehicle engines have been shown to be pro-atherogenic in apoE knockout mice and may constitute a major cardiovascular risk in humans. We posited that circulating nano-sized particles from traffic pollution sources induced vascular oxidative stress via JNK activation in endothelial cells. Diesel UFP were collected from a 1998 Kenworth truck. Intra-cellular superoxide assay revealed that these UFP dose-dependently induced superoxide (O2·-) production in human aortic endothelial cells (HAEC). Flow cytometry (FACS) showed that UFP increased MitoSOX Red intensity specific for mitochondrial superoxide. Protein carbonyl content is increased by UFP as an indication of vascular oxidative stress. UFP also up-regulated hemeoxygenase-1 (HO-1) and tissue factor (TF) mRNA expression, and pre-treatment with antioxidant, N-acetyl cysteine (NAC), significantly decreased their expression. Furthermore, UFP transiently activated JNK in HAEC. Treatment with JNK inhibitor SP600125 and silencing of both JNK1 and JNK2 with siRNA inhibited UFP stimulated O2·- production and mRNA expression of HO-1 and TF. Our findings suggest that JNK activation play an important role in UFP-induced oxidative stress and stress response gene expression. PMID:19154785

  1. Biogeography-based particle swarm optimization with fuzzy elitism and its applications to constrained engineering problems

    NASA Astrophysics Data System (ADS)

    Guo, Weian; Li, Wuzhao; Zhang, Qun; Wang, Lei; Wu, Qidi; Ren, Hongliang

    2014-11-01

    In evolutionary algorithms, elites are crucial to maintain good features in solutions. However, too many elites can make the evolutionary process stagnate and cannot enhance the performance. This article employs particle swarm optimization (PSO) and biogeography-based optimization (BBO) to propose a hybrid algorithm termed biogeography-based particle swarm optimization (BPSO) which could make a large number of elites effective in searching optima. In this algorithm, the whole population is split into several subgroups; BBO is employed to search within each subgroup and PSO for the global search. Since not all the population is used in PSO, this structure overcomes the premature convergence in the original PSO. Time complexity analysis shows that the novel algorithm does not increase the time consumption. Fourteen numerical benchmarks and four engineering problems with constraints are used to test the BPSO. To better deal with constraints, a fuzzy strategy for the number of elites is investigated. The simulation results validate the feasibility and effectiveness of the proposed algorithm.

  2. Effects of Aftermarket Control Technologies on Gas and Particle Phase Oxidative Potential from Diesel Engine Emissions.

    PubMed

    Pavlovic, Jelica; Holder, Amara L; Yelverton, Tiffany L B

    2015-09-01

    Particulate matter (PM) originating from diesel combustion is a public health concern due to its association with adverse effects on respiratory and cardiovascular diseases and lung cancer. This study investigated emissions from three stationary diesel engines (gensets) and varying power output (230 kW, 400 kW, and 600 kW) at 50% and 90% load to determine concentrations of gaseous (GROS) and PM reactive oxygen species (PMROS). In addition, the influence of three modern emission control technologies on ROS emissions was evaluated: active and passive diesel particulate filters (A-DPF and P-DPF) and a diesel oxidation catalyst (DOC). PMROS made up 30-50% of the total ROS measured without aftermarket controls. All applied controls removed PMROS by more than 75% on average. However, the oxidative potential of PM downstream of these devices was not diminished at the same rate and particles surviving the A-PDF had an even higher oxidative potential on a per PM mass basis compared to the particles emitted by uncontrolled gensets. Further, the GROS as compared to PMROS emissions were not reduced with the same efficiency (<36%). GROS concentrations were highest with the DOC in use, indicating continued formation of GROS with this control. Correlation analyses showed that PMROS and to a lesser extent GROS have a good correlation with semivolatile organic carbon (OC1) subfraction. In addition, results suggest that chemical composition, rather than PM size, is responsible for differences in the PM oxidative potential. PMID:26252945

  3. Enabling tablet product development of 5-fluorocytosine through integrated crystal and particle engineering.

    PubMed

    Perumalla, Sathyanarayana Reddy; Sun, Changquan Calvin

    2014-04-01

    The antifungal drug, 5-fluorocytosine (FC), is marketed as a capsule (250 or 500 mg strength) instead of the preferred tablet dosage form. Through systematic characterization of solid-state properties, including mechanical properties, we identify tabletability and poor physical stability of FC as the problems that likely have prevented the successful development of a FC tablet product. We then design an FC oxalate 2:1 salt (FCOXA21), based on established relationship between crystal structure and properties, to address these deficient properties. FCOXA21 is subsequently used to develop a direct compression tablet product using predictive and material-sparing powder characterization tools, that is, ring shear cell for powder flowability and compaction simulator for powder tabletability. The initial tablet formulation, which contains 84.5% (wt %) FCOXA21, exhibits excellent tabletability but inadequate flowability. We solve the powder flowability problem through controlling the particle size of FCOXA21. A batch of FCOXA21 tablets (500 mg FC equivalent dose) is then prepared. Finally, systematic evaluation on tablet weight variation, content uniformity, friability, and dissolution using standard methods confirms the commercial manufacturability of FC tablets. Through this work, we have demonstrated the potential of integrated crystal and particle engineering in expediting the development of tablet products of challenging drugs using the economical direct compression process. PMID:24515970

  4. A particle numerical model for wall film dynamics in port-injected engines

    SciTech Connect

    O`Rourke, P.J.; Amsden, A.A.

    1996-09-01

    To help predict hydrocarbon emissions during cold-start conditions the authors are developing a numerical model for the dynamics and vaporization of the liquid wall films formed in port-injected spark-ignition engines and incorporating this model in the KIVA-3 code for complex geometries. This paper summarizes the current status of the project and presents illustrative example calculations. The dynamics of the wall film is influenced by interactions with the impinging spray, the wall, and the gas flow near the wall. The spray influences the film through mass, tangential momentum, and energy addition. The wall affects the film through the no-slip boundary condition and heat transfer. The gas alters film dynamics through tangential stresses and heat and mass transfer in the gas boundary layers above the films. New wall functions are given to predict transport in the boundary layers above the vaporizing films. It is assumed the films are sufficiently thin that film flow is laminar and that liquid inertial forces are negligible. Because liquid Prandtl numbers are typically about then, unsteady heating of the film should be important and is accounted for by the model. The thin film approximation breaks down near sharp corners, where an inertial separation criterion is used. A particle numerical method is used for the wall film. This has the advantages of compatibility with the KIVA-3 spray model and of very accurate calculation of convective transport of the film. The authors have incorporated the wall film model into KIVA-3, and the resulting combined model can be used to simulate the coupled port and cylinder flows in modern spark-ignition engines. They give examples by comparing computed fuel distributions with closed- and open-valve injection during the intake and compression strokes of a generic two-valve engine.

  5. Using Peer Reviews to Examine Micropolitics and Disciplinary Development of Engineering Education: A Case Study

    ERIC Educational Resources Information Center

    Beddoes, Kacey

    2014-01-01

    This article presents a case study of the peer review process for a feminist article submitted to an engineering education journal. It demonstrates how an examination of peer review can be a useful approach to further understanding the development of feminist thought in education fields. Rather than opposition to feminist thought per se, my…

  6. Inhaled aerosol particle dosimetry in mice: a review.

    PubMed

    Méndez, Loyda B; Gookin, Glenn; Phalen, Robert F

    2010-10-01

    The availability of molecular and genetic tools has made the mouse the most common animal model for a variety of human diseases in toxicology studies. However, little is known about the factors that will influence the dose delivery to murine lungs during an inhalation study. Among these factors are the respiratory tract anatomy, lung physiology, and clearance characteristics. Therefore, the objective of this paper is to briefly review the current knowledge on the aforementioned factors in mice and their implications to the dose delivered to mouse models during inhalation studies. Representative scientific publications were chosen from searches using the NCBI PubMed and ISI Web of Knowledge databases. Relevant respiratory physiological differences have been widely reported for different mouse strains and sexes. The limited data on anatomical morphometry that is available for the murine respiratory tract indicates significant differences between mouse strains. These differences have implications to the dose delivered and the biological outcomes of inhalation studies. PMID:20879957

  7. Inhaled aerosol particle dosimetry in mice: a review.

    PubMed

    Méndez, Loyda B; Gookin, Glenn; Phalen, Robert F

    2010-12-01

    The availability of molecular and genetic tools has made the mouse the most common animal model for a variety of human diseases in toxicology studies. However, little is known about the factors that will influence the dose delivery to murine lungs during an inhalation study. Among these factors are the respiratory tract anatomy, lung physiology, and clearance characteristics. Therefore, the objective of this paper is to briefly review the current knowledge on the aforementioned factors in mice and their implications to the dose delivered to mouse models during inhalation studies. Representative scientific publications were chosen from searches using the NCBI PubMed and ISI Web of Knowledge databases. Relevant respiratory physiological differences have been widely reported for different mouse strains and sexes. The limited data on anatomical morphometry that is available for the murine respiratory tract indicates significant differences between mouse strains. These differences have implications to the dose delivered and the biological outcomes of inhalation studies. PMID:21142796

  8. The methods of formaldehyde emission testing of engine: A review

    NASA Astrophysics Data System (ADS)

    Zhang, Chunhui; Geng, Peng; Cao, Erming; Wei, Lijiang

    2015-12-01

    A number of measurements have been provided to detect formaldehyde in the atmosphere, but there are no clear unified standards in engine exhaust. Nowadays, formaldehyde, an unregulated emission from methanol engine, has been attracting increasing attention by researchers. This paper presents the detection techniques for formaldehyde emitted from the engines applied in recent market, introducing the approaches in terms of unregulated emission tests of formaldehyde, which involved gas chromatography, liquid chromatography, chromatography-mass spectrometry, chromatography-spectrum, Fourier infrared spectroscopy and spectrophotometry. The author also introduces the comparison regarding to the advantages of the existing detection techniques based on the principle, to compare with engine exhaust sampling method, the treatment in advance of detection, obtaining approaches accessing to the qualitative and quantitative analysis of chromatograms or spectra. The accuratest result obtained was chromatography though it cannot be used continuously. It also can be utilized to develop high requirements of emissions and other regulations. Fourier infrared spectroscopy has the advantage of continuous detection for a variety of unregulated emissions and can be applied to the bench in variable condition. However, its accuracy is not as good as chromatography. As the conclusion, a detection technique is chosen based on different requirements.

  9. Gas Flow, Particle Acceleration, and Heat Transfer in Cold Spray: A review

    NASA Astrophysics Data System (ADS)

    Yin, Shuo; Meyer, Morten; Li, Wenya; Liao, Hanlin; Lupoi, Rocco

    2016-06-01

    Cold spraying is increasingly attracting attentions from both scientific and industrial communities due to its unique `low-temperature' coating build-up process and its potential applications in the additive manufacturing across a variety of industries. The existing studies mainly focused on the following subjects: particle acceleration and heating, coating build-up, coating formation mechanism, coating properties, and coating applications, among which particle acceleration and heating can be regarded as the premise of the other subjects because it directly determines whether particles have sufficient energy to deposit and form the coating. Investigations on particle acceleration and heating behavior in cold spraying have been widely conducted both numerically and experimentally over decades, where many valuable conclusions were drawn. However, existing literature on this topic is vast; a systematical summery and review work is still lack so far. Besides, some curtail issues involved in modeling and experiments are still not quite clear, which needs to be further clarified. Hence, a comprehensive summary and review of the literature are very necessary. In this paper, the gas flow, particle acceleration, and heat transfer behavior in the cold spray process are systematically reviewed. Firstly, a brief introduction is given to introduce the early analytical models for predicting the gas flow and particle velocity in cold spraying. Subsequently, special attention is directed towards the application of computational fluid dynamics technique for cold spray modeling. Finally, the experimental observations and measurements in cold spraying are summarized.

  10. Gas Flow, Particle Acceleration, and Heat Transfer in Cold Spray: A review

    NASA Astrophysics Data System (ADS)

    Yin, Shuo; Meyer, Morten; Li, Wenya; Liao, Hanlin; Lupoi, Rocco

    2016-04-01

    Cold spraying is increasingly attracting attentions from both scientific and industrial communities due to its unique `low-temperature' coating build-up process and its potential applications in the additive manufacturing across a variety of industries. The existing studies mainly focused on the following subjects: particle acceleration and heating, coating build-up, coating formation mechanism, coating properties, and coating applications, among which particle acceleration and heating can be regarded as the premise of the other subjects because it directly determines whether particles have sufficient energy to deposit and form the coating. Investigations on particle acceleration and heating behavior in cold spraying have been widely conducted both numerically and experimentally over decades, where many valuable conclusions were drawn. However, existing literature on this topic is vast; a systematical summery and review work is still lack so far. Besides, some curtail issues involved in modeling and experiments are still not quite clear, which needs to be further clarified. Hence, a comprehensive summary and review of the literature are very necessary. In this paper, the gas flow, particle acceleration, and heat transfer behavior in the cold spray process are systematically reviewed. Firstly, a brief introduction is given to introduce the early analytical models for predicting the gas flow and particle velocity in cold spraying. Subsequently, special attention is directed towards the application of computational fluid dynamics technique for cold spray modeling. Finally, the experimental observations and measurements in cold spraying are summarized.

  11. Environmental concentrations of engineered nanomaterials: review of modeling and analytical studies.

    PubMed

    Gottschalk, Fadri; Sun, Tianyin; Nowack, Bernd

    2013-10-01

    Scientific consensus predicts that the worldwide use of engineered nanomaterials (ENM) leads to their release into the environment. We reviewed the available literature concerning environmental concentrations of six ENMs (TiO2, ZnO, Ag, fullerenes, CNT and CeO2) in surface waters, wastewater treatment plant effluents, biosolids, sediments, soils and air. Presently, a dozen modeling studies provide environmental concentrations for ENM and a handful of analytical works can be used as basis for a preliminary validation. There are still major knowledge gaps (e.g. on ENM production, application and release) that affect the modeled values, but over all an agreement on the order of magnitude of the environmental concentrations can be reached. True validation of the modeled values is difficult because trace analytical methods that are specific for ENM detection and quantification are not available. The modeled and measured results are not always comparable due to the different forms and sizes of particles that these two approaches target. PMID:23856352

  12. Particle-based simulations of red blood cells-A review.

    PubMed

    Ye, Ting; Phan-Thien, Nhan; Lim, Chwee Teck

    2016-07-26

    Particle-based methods have been increasingly attractive for solving biofluid flow problems, because of the ease and flexibility in modeling complex structure fluids afforded by the methods. In this review, we focus on popular particle-based methods widely used in red blood cell (RBC) simulations, including dissipative particle dynamics (DPD), smoothed particle hydrodynamics (SPH), and lattice Boltzmann method (LBM). We introduce their basic ideas and formulations, and present their applications in RBC simulations which are divided into three classes according to the number of RBCs in the simulation: a single RBC, two or multiple RBCs, and RBC suspension. Furthermore, we analyze their advantages and disadvantages. On weighing the pros and cons of the methods, a combination of the immersed boundary (IB) method and some forms of smoothed dissipative particle hydrodynamics (SDPD) methods may be required to deal effectively with RBC simulations. PMID:26706718

  13. Human-factors engineering-control-room design review: Shoreham Nuclear Power Station. Draft audit report

    SciTech Connect

    Peterson, L.R.; Preston-Smith, J.; Savage, J.W.; Rousseau, W.F.

    1981-04-24

    A human factors engineering preliminary design review of the Shoreham control room was performed at the site on March 30 through April 3, 1981. This design review was carried out by a team from the Human Factors Engineering Branch, Division of Human Factors Safety. This report was prepared on the basis of the HFEB's review of the applicant's Preliminary Design Assessment and the human factors engineering design review/audit performed at the site. The presented sections are numbered to conform to the guidelines of the draft version of NUREG-0700. They summarize the teams's observations of the control room design and layout, and of the control room operators' interface with the control room environment.

  14. A Brief Review of the Search for Isolatable Fractional Charge Elementary Particles

    SciTech Connect

    Perl, M.

    2005-01-31

    Since the initial measurements of the electron charge a century ago, experimenters have faced the persistent question as to whether elementary particles exist that have charges that are fractional multiples of the electron charge. In the standard model of particle physics the quarks are such particles, but it is assumed that quarks cannot be individually isolated, the quarks always being confined inside hadrons. This paper is a brief review of the present status of searches for isolatable fractional charge particles such as a lepton-like particle with fractional charge or an unconfined quark. There have been a very large number of searches but there is no confirmed evidence for existence of isolatable fractional charge particles. It may be that they do not exist, but it is also possible that they are very massive or that their production mechanisms are very small so that they have been missed by existing searches. Therefore the aim of this review is to urge (a) the invention of ways to substantially increase the range of known search methods and (b) to urge the invention of new search methods for isolatable fractional charge particles.

  15. Can electronic search engines optimize screening of search results in systematic reviews: an empirical study

    PubMed Central

    Sampson, Margaret; Barrowman, Nicholas J; Moher, David; Clifford, Tammy J; Platt, Robert W; Morrison, Andra; Klassen, Terry P; Zhang, Li

    2006-01-01

    Background Most electronic search efforts directed at identifying primary studies for inclusion in systematic reviews rely on the optimal Boolean search features of search interfaces such as DIALOG® and Ovid™. Our objective is to test the ability of an Ultraseek® search engine to rank MEDLINE® records of the included studies of Cochrane reviews within the top half of all the records retrieved by the Boolean MEDLINE search used by the reviewers. Methods Collections were created using the MEDLINE bibliographic records of included and excluded studies listed in the review and all records retrieved by the MEDLINE search. Records were converted to individual HTML files. Collections of records were indexed and searched through a statistical search engine, Ultraseek, using review-specific search terms. Our data sources, systematic reviews published in the Cochrane library, were included if they reported using at least one phase of the Cochrane Highly Sensitive Search Strategy (HSSS), provided citations for both included and excluded studies and conducted a meta-analysis using a binary outcome measure. Reviews were selected if they yielded between 1000–6000 records when the MEDLINE search strategy was replicated. Results Nine Cochrane reviews were included. Included studies within the Cochrane reviews were found within the first 500 retrieved studies more often than would be expected by chance. Across all reviews, recall of included studies into the top 500 was 0.70. There was no statistically significant difference in ranking when comparing included studies with just the subset of excluded studies listed as excluded in the published review. Conclusion The relevance ranking provided by the search engine was better than expected by chance and shows promise for the preliminary evaluation of large results from Boolean searches. A statistical search engine does not appear to be able to make fine discriminations concerning the relevance of bibliographic records that have

  16. A study of liquid boric oxide particle growth rates in a gas stream from a simulated jet engine combustor

    NASA Technical Reports Server (NTRS)

    Setze, Paul C

    1957-01-01

    It was experimentally determined that the liquid boric oxide particles leaving a jet engine combustor, burning a boron-containing fuel, will have diameters of 1.0 x 10(exp -5) to 2.0 x 10(exp -5) centimeter. For this size range the particle heat-transfer and drag coefficients are essentially infinite. The results may be applied to any boron-containing fuel. Equations are developed that enable the calculation of the particle size-time history. A study of boric oxide deposition mechanisms is included, and suggestions for decreading deposition rates given.

  17. Automotive Stirling engine Mod I design-review report. Volume II

    SciTech Connect

    Not Available

    1982-08-01

    Volume No. 2 of the Automotive Stirling Engine Mod I Design Review Report contains descriptions of the operating principles, performance requirements and design details of the auxiliaries and control systems for the MOD I Stirling engine system. These components and sub-systems have the following main functions: provide the required fuel and air flows for a well controlled combustion process, generating heat to the Stirling cycle; provide a driver acceptable method for controlling the power output of the engine; provide adequate lubrication and cooling water circulation; generate the electric energy required for engine and vehicle operation; provide a driver acceptable method for starting, stopping and monitoring the engine; and provide a guard system, that protects the engine at component or system malfunction.

  18. The potential of tissue engineering for developing alternatives to animal experiments: a systematic review.

    PubMed

    de Vries, Rob B M; Leenaars, Marlies; Tra, Joppe; Huijbregtse, Robbertjan; Bongers, Erik; Jansen, John A; Gordijn, Bert; Ritskes-Hoitinga, Merel

    2015-07-01

    An underexposed ethical issue raised by tissue engineering is the use of laboratory animals in tissue engineering research. Even though this research results in suffering and loss of life in animals, tissue engineering also has great potential for the development of alternatives to animal experiments. With the objective of promoting a joint effort of tissue engineers and alternative experts to fully realise this potential, this study provides the first comprehensive overview of the possibilities of using tissue-engineered constructs as a replacement of laboratory animals. Through searches in two large biomedical databases (PubMed, Embase) and several specialised 3R databases, 244 relevant primary scientific articles, published between 1991 and 2011, were identified. By far most articles reviewed related to the use of tissue-engineered skin/epidermis for toxicological applications such as testing for skin irritation. This review article demonstrates, however, that the potential for the development of alternatives also extends to other tissues such as other epithelia and the liver, as well as to other fields of application such as drug screening and basic physiology. This review discusses which impediments need to be overcome to maximise the contributions that the field of tissue engineering can make, through the development of alternative methods, to the reduction of the use and suffering of laboratory animals. PMID:23554402

  19. Improved design of a tangential entry cyclone separator for separation of particles from exhaust gas of diesel engine.

    PubMed

    Mukhopadhyay, N

    2011-01-01

    An effective design of cyclone separator with tangential inlet is developed applying an equation derived from the correlation of collection efficiency with maximum pressure drop components of the cyclone, which can efficiently remove the particles around 1microm of the exhaust gas of diesel engine. PMID:22324145

  20. Biomolecular engineering of virus-like particles aided by computational chemistry methods.

    PubMed

    Zhang, Lin; Lua, Linda H L; Middelberg, Anton P J; Sun, Yan; Connors, Natalie K

    2015-12-01

    Virus-like particles (VLPs) are repetitive organizations of viral proteins assembled in an appropriate physicochemical environment. VLPs can stimulate both innate and adaptive immune responses, due to their particulate structure enabling uptake by antigen presenting cells. These characteristics have led to successful development of VLP-vaccine products, and will ensure their vast potential in years to come. Future success of VLP therapeutic products will be determined by advances in their bioengineering, and also by the development of tools to design for their stability, function and application. This review focuses on approaches for VLP assembly in controlled chemical environments in vivo and in vitro, and the application of computational tools for improved chemical sequence design, and fundamental understanding of assembly. PMID:26383145

  1. Particle Disease: A Current Review of the Biological Mechanisms in Periprosthetic Osteolysis After Hip Arthroplasty

    PubMed Central

    Sukur, Erhan; Akman, Yunus Emre; Ozturkmen, Yusuf; Kucukdurmaz, Fatih

    2016-01-01

    Background: Inflammatory responses to wear debris cause osteolysis that leads to aseptic prosthesis loosening and hip arthroplasty failure. Although osteolysis is usually associated with aseptic loosening, it is rarely seen around stable implants. Aseptic implant loosening is a simple radiologic phenomenon, but a complex immunological process. Particulate debris produced by implants most commonly causes osteolysis, and this is called particle-associated periprosthetic osteolysis (PPO). Objective: The objective of this review is to outline the features of particle-associated periprosthetic osteolysis to allow the physician to recognise this condition and commence early treatment, thereby optimizing patient outcome. Methods: A thorough literature search was performed using available databases, including Pubmed, to cover important research published covering particle-associated PPO. Results: Although osteolysis causes bone resorption, clinical, animal, and in vitro studies of particle bioreactivity suggest that particle-associated PPO represents the culmination of several biological reactions of many cell types, rather than being caused solely by the osteoclasts. The biological activity is highly dependent on the characteristics and quantity of the wear particles. Conclusion: Despite advances in total hip arthroplasty (THA), particle-associated PPO and aseptic loosening continue to be major factors that affect prosthetic joint longevity. Biomarkers could be exploited as easy and objective diagnostic and prognostic targets that would enable testing for osteolysis after THA. Further research is needed to identify new biomarkers in PPO. A comprehensive understanding of the underlying biological mechanisms is crucial for developing new therapeutic interventions to reverse or suppress biological responses to wear particles. PMID:27499822

  2. EFFECTS OF TEMPERATURE AND PRESSURE ON PARTICLE COLLECTION MECHANISMS: THEORETICAL REVIEW

    EPA Science Inventory

    The report is a critical review and evaluation of the mechanics of aerosols at high temperatures and pressures. It discusses equations and models used to predict particle behavior at normal conditions, with regard to their applicability at high temperatures and pressures. It disc...

  3. Critical review of a quantitative study of a specialty in high energy particle physics

    SciTech Connect

    White, D H; Sullivan, D

    1980-01-01

    A review is made of the authors' series of quantitative, historical, and social studies of the weak interactions of elementary particles. A short intellectual history, the quantitative methodology, and a summary of the papers analyzing specific episodes in this field are presented. The social organization of the field is described, and an overall policy for resource management is discussed. 6 figures, 3 tables.

  4. A Review of Literature on Employability Skill Needs in Engineering

    ERIC Educational Resources Information Center

    Markes, Imren

    2006-01-01

    Encouraging skills development is a key part of the UK Government's strategy. This emphasis on skills has led to changes in Higher Education, where there is an increasing recognition of the need to enhance students' employability. This paper reviews the data on the type of employer skill needs available in the existing literature with a particular…

  5. Review: photopolymerizable and degradable biomaterials for tissue engineering applications.

    PubMed

    Ifkovits, Jamie L; Burdick, Jason A

    2007-10-01

    Photopolymerizable and degradable biomaterials are finding widespread application in the field of tissue engineering for the engineering of tissues such as bone, cartilage, and liver. The spatial and temporal control afforded by photoinitiated polymerizations has allowed for the development of injectable materials that can deliver cells and growth factors, as well as for the fabrication of scaffolding with complex structures. The materials developed for these applications range from entirely synthetic polymers (e.g., poly(ethylene glycol)) to purely natural polymers (e.g., hyaluronic acid) that are modified with photoreactive groups, with degradation based on the hydrolytic or enzymatic degradation of bonds in the polymer backbone or crosslinks. The degradation behavior also ranges from purely bulk to entirely surface degrading, based on the nature of the backbone chemistry and type of degradable units. The mechanical properties of these polymers are primarily based on factors such as the network crosslinking density and polymer concentration. As we better understand biological features necessary to control cellular behavior, smarter materials are being developed that can incorporate and mimic many of these factors. PMID:17658993

  6. Prospect of Stem Cells in Bone Tissue Engineering: A Review

    PubMed Central

    Yousefi, Azizeh-Mitra; James, Paul F.; Akbarzadeh, Rosa; Subramanian, Aswati; Flavin, Conor; Oudadesse, Hassane

    2016-01-01

    Mesenchymal stem cells (MSCs) have been the subject of many studies in recent years, ranging from basic science that looks into MSCs properties to studies that aim for developing bioengineered tissues and organs. Adult bone marrow-derived mesenchymal stem cells (BM-MSCs) have been the focus of most studies due to the inherent potential of these cells to differentiate into various cell types. Although, the discovery of induced pluripotent stem cells (iPSCs) represents a paradigm shift in our understanding of cellular differentiation. These cells are another attractive stem cell source because of their ability to be reprogramed, allowing the generation of multiple cell types from a single cell. This paper briefly covers various types of stem cell sources that have been used for tissue engineering applications, with a focus on bone regeneration. Then, an overview of some recent studies making use of MSC-seeded 3D scaffold systems for bone tissue engineering has been presented. The emphasis has been placed on the reported scaffold properties that tend to improve MSCs adhesion, proliferation, and osteogenic differentiation outcomes. PMID:26880976

  7. Numerical investigation of the influence of crystallization of ultrafine particles of aluminum oxide on energy characteristics of solid-propellant rocket engine

    NASA Astrophysics Data System (ADS)

    Dyachenko, N. N.; Dyachenko, L. I.

    2014-08-01

    The results of numerical investigation of a multiphase flow considering coagulation, crushing and crystallization of the particles of polydispersed condensate in the nozzles of solid-propellant rocket engine are presented. The influence of particles crystallization on the energy characteristics of the engine is shown.

  8. The polarization of light scattered by small particles: A personal review

    NASA Astrophysics Data System (ADS)

    Hovenier, J. W.

    2012-12-01

    A personal review of the author's field of research is presented at the occasion of his receipt of the first Van de Hulst Light-Scattering Award. Special attention is given to the relation between the author's work and the contributions of Professor H.C. van de Hulst to the field of light scattering by small particles. History, people and research are intertwined in this paper. The polarization of light scattered by particles is brought into focus. First, the interpretation of the polarization of Venus in terms of properties of its cloud particles is recorded, followed by a discussion of symmetry principles and their interrelationships. The structure of a variety of Mueller matrices is exposed. Experimental work on light scattering is also considered. Finally, the fast growth of knowledge over the past few decades pertaining to light scattering by non-spherical particles is indicated.

  9. Engineering RNA phage MS2 virus-like particles for peptide display

    NASA Astrophysics Data System (ADS)

    Jordan, Sheldon Keith

    present on the surface of the virus particle and can accept foreign sequence insertions without disruption of protein folding and viral particle assembly, and (2) on the encapsidation of nucleic acid sequences encoding both the VLP and the peptide it displays. The experiments described here are aimed at satisfying the first of these two requirements by engineering efficient peptide display at two different sites in MS2 coat protein. First, we evaluated the suitability of the N-terminus of MS2 coat for peptide insertions. It was observed that random N-terminal 10-mer fusions generally disrupted protein folding and VLP assembly, but by bracketing the foreign sequences with certain specific dipeptides, these defects could be suppressed. Next, the suitability of a coat protein surface loop for foreign sequence insertion was tested. Specifically, random sequence peptides were inserted into the N-terminal-most AB-loop of a coat protein single-chain dimer. Again we found that efficient display required the presence of appropriate dipeptides bracketing the peptide insertion. Finally, it was shown that an N-terminal fusion that tended to interfere specifically with capsid assembly could be efficiently incorporated into mosaic particles when co-expressed with wild-type coat protein.

  10. [Research on engine remaining useful life prediction based on oil spectrum analysis and particle filtering].

    PubMed

    Sun, Lei; Jia, Yun-xian; Cai, Li-ying; Lin, Guo-yu; Zhao, Jin-song

    2013-09-01

    The spectrometric oil analysis(SOA) is an important technique for machine state monitoring, fault diagnosis and prognosis, and SOA based remaining useful life(RUL) prediction has an advantage of finding out the optimal maintenance strategy for machine system. Because the complexity of machine system, its health state degradation process can't be simply characterized by linear model, while particle filtering(PF) possesses obvious advantages over traditional Kalman filtering for dealing nonlinear and non-Gaussian system, the PF approach was applied to state forecasting by SOA, and the RUL prediction technique based on SOA and PF algorithm is proposed. In the prediction model, according to the estimating result of system's posterior probability, its prior probability distribution is realized, and the multi-step ahead prediction model based on PF algorithm is established. Finally, the practical SOA data of some engine was analyzed and forecasted by the above method, and the forecasting result was compared with that of traditional Kalman filtering method. The result fully shows the superiority and effectivity of the PMID:24369656