DOE Office of Scientific and Technical Information (OSTI.GOV)

Bustamante, Mauricio; Heinze, Jonas; Winter, Walter

Gamma-ray bursts (GRBs) are promising as sources of neutrinos and cosmic rays. In the internal shock scenario, blobs of plasma emitted from a central engine collide within a relativistic jet and form shocks, leading to particle acceleration and emission. Motivated by present experimental constraints and sensitivities, we improve the predictions of particle emission by investigating time-dependent effects from multiple shocks. We produce synthetic light curves with different variability timescales that stem from properties of the central engine. For individual GRBs, qualitative conclusions about model parameters, neutrino production efficiency, and delays in high-energy gamma-rays can be deduced from inspection of themore » gamma-ray light curves. GRBs with fast time variability without additional prominent pulse structure tend to be efficient neutrino emitters, whereas GRBs with fast variability modulated by a broad pulse structure can be inefficient neutrino emitters and produce delayed high-energy gamma-ray signals. Our results can be applied to quantitative tests of the GRB origin of ultra-high-energy cosmic rays, and have the potential to impact current and future multi-messenger searches.« less

Theories of central engine for long gamma-ray bursts

NASA Astrophysics Data System (ADS)

Nagataki, Shigehiro

2018-02-01

Long GRBs are the most powerful explosions in the universe since the Big Bang. At least, some fraction of long GRBs are born from the death of massive stars. Likewise, only some fraction of massive stars that satisfy additional special conditions explode as long GRBs associated with supernovae/hypernovae. In this paper, we discuss the explosion mechanism of long GRBs associated with hypernovae: ‘the central engine of long GRBs’. The central engine of long GRBs is very different from that of core-collapse supernovae, although the mechanism of the engine is still not firmly established. In this paper, we review theoretical studies of the central engine of long GRBs. First, we discuss possible progenitor stars. Then several promising mechanisms of the central engine—such as black hole and magnetar formation—will be reviewed. We will also mention some more exotic models. Finally, we describe prospects for future studies of the central engine of long GRBs.

The development of a center cell structure in bonded aluminum for the Ferrari 408 research vehicle

DOE Office of Scientific and Technical Information (OSTI.GOV)

Seeds, A.; Nardini, D.; Cassese, F.

1989-01-01

In F408 research vehicle has enabled Ferrari Engineering to evaluate new forms of transmission, suspension, bodywork and structure for future production vehicles. As Alcan worked with Ferrari Engineering to adapt its Aluminum Structured Vehicle Technology (ASVT) to develop a bonded version of a central section of the structure (center cell). This paper begins with an outline of the major F408 project objectives and indicates the performance and manufacturing advantages for the features of interest, particularly the center cell structure. The paper describes the development stages of the bonded aluminum center cell. It shows that the performance and manufacturing objectives weremore » met with a substantial weight-saving and improvement in stiffness compared to laser-welded stainless steel. The paper concludes with a summary of the other technical innovations and developments in the F408 vehicle.« less

Acoustic transducer in system for gas temperature measurement in gas turbine engine

DOE Office of Scientific and Technical Information (OSTI.GOV)

DeSilva, Upul P.; Claussen, Heiko

An apparatus for controlling operation of a gas turbine engine including at least one acoustic transmitter/receiver device located on a flow path boundary structure. The acoustic transmitter/receiver device includes an elongated sound passage defined by a surface of revolution having opposing first and second ends and a central axis extending between the first and second ends, an acoustic sound source located at the first end, and an acoustic receiver located within the sound passage between the first and second ends. The boundary structure includes an opening extending from outside the boundary structure to the flow path, and the second endmore » of the surface of revolution is affixed to the boundary structure at the opening for passage of acoustic signals between the sound passage and the flow path.« less

Space construction activities

NASA Technical Reports Server (NTRS)

1991-01-01

The Center for Space Construction at the University of Colorado at Boulder was established in 1988 as a University Space Engineering Research Center. The mission of the Center is to conduct interdisciplinary engineering research which is critical to the construction of future space structures and systems and to educate students who will have the vision and technical skills to successfully lead future space construction activities. The research activities are currently organized around two central projects: Orbital Construction and Lunar Construction. Summaries of the research projects are included.

The centrality of RNA for engineering gene expression

PubMed Central

Chappell, James; Takahashi, Melissa K; Meyer, Sarai; Loughrey, David; Watters, Kyle E; Lucks, Julius

2013-01-01

Synthetic biology holds promise as both a framework for rationally engineering biological systems and a way to revolutionize how we fundamentally understand them. Essential to realizing this promise is the development of strategies and tools to reliably and predictably control and characterize sophisticated patterns of gene expression. Here we review the role that RNA can play towards this goal and make a case for why this versatile, designable, and increasingly characterizable molecule is one of the most powerful substrates for engineering gene expression at our disposal. We discuss current natural and synthetic RNA regulators of gene expression acting at key points of control – transcription, mRNA degradation, and translation. We also consider RNA structural probing and computational RNA structure predication tools as a way to study RNA structure and ultimately function. Finally, we discuss how next-generation sequencing methods are being applied to the study of RNA and to the characterization of RNA's many properties throughout the cell. PMID:24124015

Mapping the Emergence of Synthetic Biology

PubMed Central

2016-01-01

In this paper, we apply an original scientometric analyses to a corpus comprising synthetic biology (SynBio) publications in Thomson Reuters Web of Science to characterize the emergence of this new scientific field. Three results were drawn from this empirical investigation. First, despite the exponential growth of publications, the study of population level statistics (newcomers proportion, collaboration network structure) shows that SynBio has entered a stabilization process since 2010. Second, the mapping of textual and citational networks shows that SynBio is characterized by high heterogeneity and four different approaches: the central approach, where biobrick engineering is the most widespread; genome engineering; protocell creation; and metabolic engineering. We suggest that synthetic biology acts as an umbrella term allowing for the mobilization of resources, and also serves to relate scientific content and promises of applications. Third, we observed a strong intertwinement between epistemic and socio-economic dynamics. Measuring scientific production and impact and using structural analysis data, we identified a core set of mostly American scientists. Biographical analysis shows that these central and influential scientists act as “boundary spanners,” meaning that their importance to the field lies not only in their academic contributions, but also in their capacity to interact with other social spaces that are outside the academic sphere. PMID:27611324

Centralized remote structural monitoring and management of real-time data

NASA Astrophysics Data System (ADS)

Han, Liting; Newhook, John P.; Mufti, Aftab A.

2004-07-01

Structural health monitoring (SHM) activities in civil engineering are increasing at a rapid pace in both research and field applications. This paper addresses the specific issue of incorporating internet technology into a structural health monitoring program. The issue of data volume versus communication speed is discussed along with a practical solution employed by ISIS Canada. The approach is illustrated through reference to several current case studies which include two bridges and a statue. It is seen that although the specifics of the projects and monitoring needs are different, the manner in which on-line monitoring can be conducted is very similar and easily allows for centralized monitoring. A general framework for website construction integrating sensing data and web camera options are presented. Issues related to simple real-time performance indices versus more comprehensive complex data analysis are discussed. Examples of on-line websites which allow visualization of new and historic data are presented. The paper also discusses future activities and research needs related to centralized remote structural monitoring and management of real-time data.

Infrared polarimetry of Mrk 231: scattering off hot dust grains in the central core

NASA Astrophysics Data System (ADS)

Lopez-Rodriguez, E.; Packham, C.; Jones, T. J.; Siebenmorgen, R.; Roche, P. F.; Levenson, N. A.; Alonso-Herrero, A.; Perlman, E.; Ichikawa, K.; Ramos Almeida, C.; González-Martín, O.; Nikutta, R.; Martinez-Paredez, M.; Shenoy, D.; Gordon, M. S.; Telesco, C. M.

2017-01-01

We present high-angular (0.17-0.35 arcsec) resolution imaging polarimetric observations of Mrk 231 in the 3.1 μm filter using MMT-Pol on the 6.5-m MMT, and in the 8.7, 10.3, and 11.6 μm filters using CanariCam on the 10.4-m Gran Telescopio CANARIAS. In combination with already published observations, we compile the 1-12 μm total and polarized nuclear spectral energy distribution (SED). The total flux SED in the central 400 pc is explained as the combination of (1) a hot (731 ± 4 K) dusty structure, directly irradiated by the central engine, which is at 1.6 ± 0.1 pc away and attributed to be in the pc-scale polar region, (2) an optically-thick, smooth and disc-like dusty structure (`torus') with an inclination of 48° ± 23° surrounding the central engine, and (3) an extinguished (AV = 36 ± 5 mag) starburst component. The polarized SED decreases from 0.77 ± 0.14 per cent at 1.2 μm to 0.31 ± 0.15 per cent at 11.6 μm and follows a power-law function, λ˜0.57. The polarization angle remains constant (˜108°) in the 1-12 μm wavelength range. The dominant polarization mechanism is explained as scattering-off hot dust grains in the pc-scale polar regions.

Structure of Quasar Continuum Emission Regions and Cosmology from Optical and X-Ray Microlensing in Gravitationally Lensed Quasars

DTIC Science & Technology

2008-05-02

information is estimated to average 1 hour per response, including g the time for reviewing instructions, searching existing data sources, gathering...their central engines cannot be resolved with ordinary telescopes. Gravitational telescopes, however, provide the necessary resolution to study the...structure of the continuum emission regions at optical and X-ray wavelengths and make time delay estimates in the systems in which sufficient data were

Counterspaces for Women of Color in STEM Higher Education: Marginal and Central Spaces for Persistence and Success

ERIC Educational Resources Information Center

Ong, Maria; Smith, Janet M.; Ko, Lily T.

2018-01-01

Counterspaces in science, technology, engineering, and mathematics (STEM) are often considered "safe spaces" at the margins for groups outside the mainstream of STEM education. The prevailing culture and structural manifestations in STEM have traditionally privileged norms of success that favor competitive, individualistic, and solitary…

Recommendations for Benchmarking Web Site Usage among Academic Libraries.

ERIC Educational Resources Information Center

Hightower, Christy; Sih, Julie; Tilghman, Adam

1998-01-01

To help library directors and Web developers create a benchmarking program to compare statistics of academic Web sites, the authors analyzed the Web server log files of 14 university science and engineering libraries. Recommends a centralized voluntary reporting structure coordinated by the Association of Research Libraries (ARL) and a method for…

Multi-messenger Light Curves from Gamma-Ray Bursts in the Internal Shock Model

NASA Astrophysics Data System (ADS)

Bustamante, Mauricio; Heinze, Jonas; Murase, Kohta; Winter, Walter

2017-03-01

Gamma-ray bursts (GRBs) are promising as sources of neutrinos and cosmic rays. In the internal shock scenario, blobs of plasma emitted from a central engine collide within a relativistic jet and form shocks, leading to particle acceleration and emission. Motivated by present experimental constraints and sensitivities, we improve the predictions of particle emission by investigating time-dependent effects from multiple shocks. We produce synthetic light curves with different variability timescales that stem from properties of the central engine. For individual GRBs, qualitative conclusions about model parameters, neutrino production efficiency, and delays in high-energy gamma-rays can be deduced from inspection of the gamma-ray light curves. GRBs with fast time variability without additional prominent pulse structure tend to be efficient neutrino emitters, whereas GRBs with fast variability modulated by a broad pulse structure can be inefficient neutrino emitters and produce delayed high-energy gamma-ray signals. Our results can be applied to quantitative tests of the GRB origin of ultra-high-energy cosmic rays, and have the potential to impact current and future multi-messenger searches.

Social Network Theory in Engineering Education

NASA Astrophysics Data System (ADS)

Simon, Peter A.

Collaborative groups are important both in the learning environment of engineering education and, in the real world, the business of engineering design. Selecting appropriate individuals to form an effective group and monitoring a group's progress are important aspects of successful task performance. This exploratory study looked at using the concepts of cognitive social structures, structural balance, and centrality from social network analysis as well as the measures of emotional intelligence. The concepts were used to analyze potential team members to examine if an individual's ability to perceive emotion in others and the self and to use, understand, and manage those emotions are a factor in a group's performance. The students from a capstone design course in computer engineering were used as volunteer subjects. They were formed into groups and assigned a design exercise to determine whether and which of the above-mentioned tools would be effective in both selecting teams and predicting the quality of the resultant design. The results were inconclusive with the exception of an individual's ability to accurately perceive emotions. The instruments that were successful were the Self-Monitoring scale and the accuracy scores derived from cognitive social structures and Level IV of network levels of analysis.

Engineering Approaches to Illuminating Brain Structure and Dynamics

PubMed Central

Deisseroth, Karl; Schnitzer, Mark J.

2017-01-01

Historical milestones in neuroscience have come in diverse forms, ranging from the resolution of specific biological mysteries via creative experimentation to broad technological advances allowing neuroscientists to ask new kinds of questions. The continuous development of tools is driven with a special necessity by the complexity, fragility, and inaccessibility of intact nervous systems, such that inventive technique development and application drawing upon engineering and the applied sciences has long been essential to neuroscience. Here we highlight recent technological directions in neuroscience spurred by progress in optical, electrical, mechanical, chemical, and biological engineering. These research areas are poised for rapid growth and will likely be central to the practice of neuroscience well into the future. PMID:24183010

Microphysics in the Gamma-Ray Burst Central Engine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Janiuk, Agnieszka, E-mail: agnes@cft.edu.pl

We calculate the structure and evolution of a gamma-ray burst central engine where an accreting torus has formed around the newly born black hole. We study the general relativistic, MHD models and we self-consistently incorporate the nuclear equation of state. The latter accounts for the degeneracy of relativistic electrons, protons, and neutrons, and is used in the dynamical simulation, instead of a standard polytropic γ -law. The EOS provides the conditions for the nuclear pressure in the function of density and temperature, which evolve with time according to the conservative MHD scheme. We analyze the structure of the torus andmore » outflowing winds, and compute the neutrino flux emitted through the nuclear reaction balance in the dense and hot matter. We also estimate the rate of transfer of the black-hole rotational energy to the bipolar jets. Finally, we elaborate on the nucleosynthesis of heavy elements in the accretion flow and the wind, through computations of the thermonuclear reaction network. We discuss the possible signatures of the radioactive element decay in the accretion flow. We suggest that further detailed modeling of the accretion flow in the GRB engine, together with its microphysics, may be a valuable tool to constrain the black-hole mass and spin. It can be complementary to the gravitational wave analysis if the waves are detected with an electromagnetic counterpart.« less

8. ENGINE TEST CELL BUILDING INTERIOR. LONGITUDINAL CENTRAL PASSAGEWAY IN ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

8. ENGINE TEST CELL BUILDING INTERIOR. LONGITUDINAL CENTRAL PASSAGEWAY IN BASEMENT. LOOKING SOUTHWEST. - Fairchild Air Force Base, Engine Test Cell Building, Near intersection of Arnold Street & George Avenue, Spokane, Spokane County, WA

5. ENGINE TEST CELL BUILDING INTERIOR. CENTRAL ROOM ON MAIN ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

5. ENGINE TEST CELL BUILDING INTERIOR. CENTRAL ROOM ON MAIN FLOOR. LOOKING NORTHWEST. - Fairchild Air Force Base, Engine Test Cell Building, Near intersection of Arnold Street & George Avenue, Spokane, Spokane County, WA

6. ENGINE TEST CELL BUILDING INTERIOR. CENTRAL OFFICE AREA ON ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

6. ENGINE TEST CELL BUILDING INTERIOR. CENTRAL OFFICE AREA ON BASEMENT LEVEL. LOOKING WEST. - Fairchild Air Force Base, Engine Test Cell Building, Near intersection of Arnold Street & George Avenue, Spokane, Spokane County, WA

7. ENGINE TEST CELL BUILDING INTERIOR. WALL MAP IN CENTRAL ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

7. ENGINE TEST CELL BUILDING INTERIOR. WALL MAP IN CENTRAL BASEMENT OFFICE AREA. LOOKING SOUTHWEST. - Fairchild Air Force Base, Engine Test Cell Building, Near intersection of Arnold Street & George Avenue, Spokane, Spokane County, WA

The Case for Distributed Engine Control in Turbo-Shaft Engine Systems

NASA Technical Reports Server (NTRS)

Culley, Dennis E.; Paluszewski, Paul J.; Storey, William; Smith, Bert J.

2009-01-01

The turbo-shaft engine is an important propulsion system used to power vehicles on land, sea, and in the air. As the power plant for many high performance helicopters, the characteristics of the engine and control are critical to proper vehicle operation as well as being the main determinant to overall vehicle performance. When applied to vertical flight, important distinctions exist in the turbo-shaft engine control system due to the high degree of dynamic coupling between the engine and airframe and the affect on vehicle handling characteristics. In this study, the impact of engine control system architecture is explored relative to engine performance, weight, reliability, safety, and overall cost. Comparison of the impact of architecture on these metrics is investigated as the control system is modified from a legacy centralized structure to a more distributed configuration. A composite strawman system which is typical of turbo-shaft engines in the 1000 to 2000 hp class is described and used for comparison. The overall benefits of these changes to control system architecture are assessed. The availability of supporting technologies to achieve this evolution is also discussed.

Jet in jet in M87

NASA Astrophysics Data System (ADS)

Sob'yanin, Denis Nikolaevich

2017-11-01

New high-resolution Very Long Baseline Interferometer observations of the prominent jet in the M87 radio galaxy show a persistent triple-ridge structure of the transverse 15-GHz profile with a previously unobserved ultra-narrow central ridge. This radio structure can reflect the intrinsic structure of the jet, so that the jet as a whole consists of two embedded coaxial jets. A relativistic magnetohydrodynamic model is considered in which an inner jet is placed inside a hollow outer jet and the electromagnetic fields, pressures and other physical quantities are found. The entire jet is connected to the central engine that plays the role of a unipolar inductor generating voltage between the jets and providing opposite electric currents, and the charge neutrality and current closure together with the electromagnetic fields between the jets can contribute to the jet stabilization. The constant voltage is responsible for the similar widening laws observed for the inner and outer jets. This jet-in-jet structure can indicate simultaneous operation of two different jet-launching mechanisms, one relating to the central supermassive black hole and the other to the surrounding accretion disc. An inferred magnetic field of 80 G at the base is sufficient to provide the observed jet luminosity.

Extracting information from multiplex networks

NASA Astrophysics Data System (ADS)

Iacovacci, Jacopo; Bianconi, Ginestra

2016-06-01

Multiplex networks are generalized network structures that are able to describe networks in which the same set of nodes are connected by links that have different connotations. Multiplex networks are ubiquitous since they describe social, financial, engineering, and biological networks as well. Extending our ability to analyze complex networks to multiplex network structures increases greatly the level of information that is possible to extract from big data. For these reasons, characterizing the centrality of nodes in multiplex networks and finding new ways to solve challenging inference problems defined on multiplex networks are fundamental questions of network science. In this paper, we discuss the relevance of the Multiplex PageRank algorithm for measuring the centrality of nodes in multilayer networks and we characterize the utility of the recently introduced indicator function Θ ˜ S for describing their mesoscale organization and community structure. As working examples for studying these measures, we consider three multiplex network datasets coming for social science.

10. SOUTHEAST EXTERIOR CORNER. During demolition large iron bars were ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

10. SOUTHEAST EXTERIOR CORNER. During demolition large iron bars were found embedded in the south brick walls about 11 courses above the water table. These were possibly used to secure the roof structure of a shed which housed the fire engine of the Relief Fire Company (see Articles of Agreement, 1815, papers of the Central Philadelphia Meeting), which specified that the Engine House was to be situated at the northeast corner of the lot. Perhaps at some later date the shed was moved. - Twelfth Street Meeting House, 20 South Twelfth Street, Philadelphia, Philadelphia County, PA

APPALACHIAN FOLDS, LATERAL RAMPS, AND BASEMENT FAULTS: A MODERN ENGINEERING PROBLEM?

USGS Publications Warehouse

Pohn, Howard A.

1987-01-01

Field studies and analysis of radar data have shown that cross-strike faulting in the central and southern Appalachians has affected geologic structures at the surface. These basement faults appear to have been active through much of geologic time. Indeed, more than 45 percent of modern earthquakes occur along these narrow zones here termed 'lateral ramps. ' Because of this seismic activity, these lateral ramps are likely to be zones that are prone to slope failure. The engineer should be aware of the presence of such zones and the higher landslide potential along them.

Experimental Tensile Strength Analysis of Woven-Glass/Epoxy Composite Plates with Central Circular Hole

NASA Astrophysics Data System (ADS)

Hadi, Bambang K.; Rofa, Bima K.

2018-04-01

The use of composite materials in aerospace engineering, as well as in maritime structure has increased significantly during the recent years. The extensive use of composite materials in industrial applications should make composite structural engineers and scientists more aware of the advantage and disadvantage of this material and provide them with necessary data and certification process. One of the problems in composite structures is the existence of hole. Hole can not be avoided in actual structures, since it may be the necessity of providing access for maintenance or due to impact damage. The presence of hole will weaken the structures. Therefore, in this paper, the effect of hole on the strength of glass-woven/epoxy composite will be discussed. Extensive tests have been carried out to study the effect of hole-diameter on the tensile strengths of these specimens. The results showed that the bigger the hole-diameter compared to the width of the specimens has weakened the structures further, as expected. Further study should be carried in the future to model it with the finite element and theoretical analysis precisely.

Engineering approaches to illuminating brain structure and dynamics.

PubMed

Deisseroth, Karl; Schnitzer, Mark J

2013-10-30

Historical milestones in neuroscience have come in diverse forms, ranging from the resolution of specific biological mysteries via creative experimentation to broad technological advances allowing neuroscientists to ask new kinds of questions. The continuous development of tools is driven with a special necessity by the complexity, fragility, and inaccessibility of intact nervous systems, such that inventive technique development and application drawing upon engineering and the applied sciences has long been essential to neuroscience. Here we highlight recent technological directions in neuroscience spurred by progress in optical, electrical, mechanical, chemical, and biological engineering. These research areas are poised for rapid growth and will likely be central to the practice of neuroscience well into the future. Copyright © 2013 Elsevier Inc. All rights reserved.

Vortex flows with suspended separation regions and long-range untwisted central jets

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abramovich, G.N.; Trofimov, R.S.

1988-05-01

A study is made of possible physicoaerodynamic configurations of vortical flow with suspended separation regions and untwisted central jets. Such flows are encountered in power plants (heat exchangers, combustion chambers, and chemical reactors) and in nature (tornadoes). The basic configurations of several flows of this type are described, including the structure of a flow formed by coaxial cocurrent twisted jets, the flow in a conical swirl chamber with the formation of an untwisted long-range axial jet, the flow pattern in a gas turbine engine chamber, and some considerations regarding the aerodynamics of a tornado.

Development of a morphing structure with the incorporation of central pattern generators

NASA Astrophysics Data System (ADS)

Bliss, Thomas K.; Bart-Smith, Hilary; Iwasaki, Tetsuya

2006-03-01

The Manta Ray, Manta birostris, is an amazing creature, propelling itself through the water with the elegant and complex flapping of its wings. Achieving outstanding efficiencies, engineers are looking for ways to mimic its flight through the water and harness its propulsive techniques. This study combines two biologically inspired aspects to achieve this goal: morphing structures actuated with a biomimetic neural network control system. It is believed that this combination will prove capable of producing the oscillatory motions necessary for locomotion. In this paper, a four-truss structure with three actuators is chosen and its performance capabilities are analyzed. A synthetic central pattern generator, which provides the fundamental control mechanisms for rhythmic motion in animals, is designed to realize an oscillatory control of the three actuators. The control system is simulated using Matlab, then combined with LabVIEW to control the four-truss structure. The system's performance is analyzed, with specific attention to both transient and steady-state behavior.

Magnetic dipolar ordering and hysteresis of geometrically defined nanoparticle clusters

NASA Astrophysics Data System (ADS)

Kure, Mathias; Beleggia, Marco; Frandsen, Cathrine

2017-10-01

Magnetic nanoparticle clusters have several biomedical and engineering applications, and revealing the basic interplay between particle configuration and magnetic properties is important for tuning the clusters for specific uses. Here, we consider the nanoparticles as macrospins and use computer simulations to determine their magnetic configuration when placed at the vertices of various polyhedra. We find that magnetic dipoles of equal magnitude arrange in flux-closed vortices on a layer basis, giving the structures a null remanent magnetic moment. Assigning a toroidal moment to each layer, we find that the geometrical arrangement, i.e., "triangular packing" vs. "square packing," of the moments in the adjacent layer determines whether the flux-closed layers are ferrotoroidal (co-rotating vortices) or antiferrotoroidal (counter-rotating vortices). Interestingly, upon adding a single magnetic moment at the center of the polyhedra, the central moment relaxes along one of the principal axes and induces partial alignment of the surrounding moments. The resulting net moment is up to nearly four times that of the single moment added. Furthermore, we model quasi-static hysteresis loops for structures with and without a central moment. We find that a central moment ensures an opening of the hysteresis loop, and the resultant loop areas are typically many-fold larger compared to the same structure without a central moment.

Engineering central metabolism - a grand challenge for plant biologists.

PubMed

Sweetlove, Lee J; Nielsen, Jens; Fernie, Alisdair R

2017-05-01

The goal of increasing crop productivity and nutrient-use efficiency is being addressed by a number of ambitious research projects seeking to re-engineer photosynthetic biochemistry. Many of these projects will require the engineering of substantial changes in fluxes of central metabolism. However, as has been amply demonstrated in simpler systems such as microbes, central metabolism is extremely difficult to rationally engineer. This is because of multiple layers of regulation that operate to maintain metabolic steady state and because of the highly connected nature of central metabolism. In this review we discuss new approaches for metabolic engineering that have the potential to address these problems and dramatically improve the success with which we can rationally engineer central metabolism in plants. In particular, we advocate the adoption of an iterative 'design-build-test-learn' cycle using fast-to-transform model plants as test beds. This approach can be realised by coupling new molecular tools to incorporate multiple transgenes in nuclear and plastid genomes with computational modelling to design the engineering strategy and to understand the metabolic phenotype of the engineered organism. We also envisage that mutagenesis could be used to fine-tune the balance between the endogenous metabolic network and the introduced enzymes. Finally, we emphasise the importance of considering the plant as a whole system and not isolated organs: the greatest increase in crop productivity will be achieved if both source and sink metabolism are engineered. © 2016 The Authors The Plant Journal © 2016 John Wiley & Sons Ltd.

A distributed query execution engine of big attributed graphs.

PubMed

Batarfi, Omar; Elshawi, Radwa; Fayoumi, Ayman; Barnawi, Ahmed; Sakr, Sherif

2016-01-01

A graph is a popular data model that has become pervasively used for modeling structural relationships between objects. In practice, in many real-world graphs, the graph vertices and edges need to be associated with descriptive attributes. Such type of graphs are referred to as attributed graphs. G-SPARQL has been proposed as an expressive language, with a centralized execution engine, for querying attributed graphs. G-SPARQL supports various types of graph querying operations including reachability, pattern matching and shortest path where any G-SPARQL query may include value-based predicates on the descriptive information (attributes) of the graph edges/vertices in addition to the structural predicates. In general, a main limitation of centralized systems is that their vertical scalability is always restricted by the physical limits of computer systems. This article describes the design, implementation in addition to the performance evaluation of DG-SPARQL, a distributed, hybrid and adaptive parallel execution engine of G-SPARQL queries. In this engine, the topology of the graph is distributed over the main memory of the underlying nodes while the graph data are maintained in a relational store which is replicated on the disk of each of the underlying nodes. DG-SPARQL evaluates parts of the query plan via SQL queries which are pushed to the underlying relational stores while other parts of the query plan, as necessary, are evaluated via indexless memory-based graph traversal algorithms. Our experimental evaluation shows the efficiency and the scalability of DG-SPARQL on querying massive attributed graph datasets in addition to its ability to outperform the performance of Apache Giraph, a popular distributed graph processing system, by orders of magnitudes.

Cooperation with Central and Eastern Europe in Language Engineering.

ERIC Educational Resources Information Center

Andersen, Poul

This paper outlines trends and activities in Central and Eastern European language research and language-related software development (language engineering) and briefly describes some specific projects. The language engineering segment of the European Union's Fourth Framework Programme, intended to facilitate use of telematics applications and…

Central Engine Memory of Gamma-Ray Bursts and Soft Gamma-Ray Repeaters

NASA Astrophysics Data System (ADS)

Zhang, Bin-Bin; Zhang, Bing; Castro-Tirado, Alberto J.

2016-04-01

Gamma-ray bursts (GRBs) are bursts of γ-rays generated from relativistic jets launched from catastrophic events such as massive star core collapse or binary compact star coalescence. Previous studies suggested that GRB emission is erratic, with no noticeable memory in the central engine. Here we report a discovery that similar light curve patterns exist within individual bursts for at least some GRBs. Applying the Dynamic Time Warping method, we show that similarity of light curve patterns between pulses of a single burst or between the light curves of a GRB and its X-ray flare can be identified. This suggests that the central engine of at least some GRBs carries “memory” of its activities. We also show that the same technique can identify memory-like emission episodes in the flaring emission in soft gamma-ray repeaters (SGRs), which are believed to be Galactic, highly magnetized neutron stars named magnetars. Such a phenomenon challenges the standard black hole central engine models for GRBs, and suggest a common physical mechanism behind GRBs and SGRs, which points toward a magnetar central engine of GRBs.

Mechanical performance evaluation of the CFETR central solenoid model coil design

NASA Astrophysics Data System (ADS)

Liu, Xiaogang; Wang, Zhaoliang; Ren, Yong; Li, Junjun; Yin, Dapeng; Li, Lei; Gao, Xiang; Wu, Yu

2018-01-01

The Chinese Fusion Engineering Test Reactor (CFETR) Central Solenoid Model Coil is being fabricated by the Institute of Plasma Physics Chinese Academy of Sciences. The Model Coil is comprised of Nb3Sn and NbTi modules held together by a preload structure. It will operate at 4.5 K to produce a peak field of 12 T at 48 kA. In order to investigate the feasibility and integrity of the Model Coil design before its manufacturing, the mechanical performance has been evaluated for the room temperature preload, 4.5 K stand-by and 48 kA operating conditions. A 1/15 3D detailed model that consists of jackets, insulations, bladders, buffers and preload structure, is constructed and simulated using the coupled structural-thermal-electromagnetic solver of ANSYS. In contrary to a smeared winding pack model, our analysis with the detailed model can directly and precisely simulate the differential thermal contraction effect of the preload structure, jacket and insulations, as well as the electromagnetic load acting on the jacket. The detailed deformation and stress behaviors of the Model Coil are illustrated and discussed. The results indicate that the final design of the CFETR Central Solenoid Model Coil is reasonably conservative and satisfy the design criteria.

Apollo Lightcraft Project

NASA Technical Reports Server (NTRS)

Myrabo, Leik N.; Atonison, Mark A. (Editor); Chen, Sammy G. (Editor); Decusatis, Casimer (Editor); Kusche, Karl P. (Editor); Minucci, Marco A. (Editor); Moder, Jeffrey P. (Editor); Morales, Ciro (Editor); Nelson, Caroline V. (Editor); Richard, Jacques C. (Editor)

1989-01-01

The ultimate goal for this NASA/USRA-sponsored Apollo Lightcraft Project is to develop a revolutionary manned launch vehicle technology which can potentially reduce payload transport costs by a factor of 1000 below the Space Shuttle Orbiter. The Rensselaer design team proposes to utilize advanced, highly energetic, beamed-energy sources (laser, microwave) and innovative combined-cycle (airbreathing/rocket) engines to accomplish this goal. The research effort focuses on the concept of a 100 MW-class, laser-boosted Lightcraft Technology Demonstrator (LTD) drone. The preliminary conceptual design of this 1.4 meter diameter microspacecraft involved an analytical performance analysis of the transatmospheric engine in its two modes of operation (including an assessment of propellant and tankage requirements), and a detailed design of internal structure and external aeroshell configuration. The central theme of this advanced propulsion research was to pick a known excellent working fluid (i.e., air or LN sub 2), and then to design a combined-cycle engine concept around it. Also, a structural vibration analysis was performed on the annular shroud pulsejet engine. Finally, the sensor satellite mission was examined to identify the requisite subsystem hardware: e.g., electrical power supply, optics and sensors, communications and attitude control systems.

A lightweight pumped hydrazine orbit maneuvering space vehicle

NASA Astrophysics Data System (ADS)

Whitehead, J. C.

1992-01-01

An orbital maneuvering vehicle has a pair of opposed cylindrical piston tanks for hydrazine, and four transverse liquid rocket engines along a longitudinal plane. A new kind of pumped rocket propulsion provides maneuvering thrust on demand, and free-piston pumps which can rapidly start and stop are radially oriented between thrusters. A major advantage of this configuration is that the tanks can be close together, which maximizes the vehicle's longitudinal bending stiffness while minimizing the mass of the central bridging structure. The impulses from pump exhaust and piston reciprocation are directed through the system mass center, so they apply no disturbance torques. All high-temperature components are located on the outside of the central structure, where they are free to expand and radiate heat without detrimental effects. Virtually all lightweight components have been fabricated and tested, and photographs of hardware subassemblies are presented.

Diode-pumped laser performance of Tm:Sc2SiO5 crystal at 1971 nm

NASA Astrophysics Data System (ADS)

Liu, Bin; Zheng, Li-He; Wang, Qing-Guo; Liu, Jun-Fang; Su, Liang-Bi; Tang, Hui-Li; Liu, Jie; Fan, Xiu-Wei; Wu, Feng; Luo, Ping; Zhao, Heng-Yu; Shi, Jiao-Jiao; He, Nuo-Tian; Li, Na; Li, Qiu; Guo, Chao; Xu, Xiao-Dong; Wang, Zhan-Shan; Xu, Jun

2017-08-01

Not Available Project supported by the Shanghai Municipal Engineering Research Center for Sapphire Crystals, China (Grant No. 14DZ2252500), the Fund of Key Laboratory of Optoelectronic Materials Chemistry and Physics, Chinese Academy of Sciences (Grant No. 2008DP17301), the Fundamental Research Funds for the Central Universities, the National Natural Science Foundation of China and the China Academy of Engineering Physics Joint Fund (Grant No. U1530152), the National Natural Science Foundation of China (Grant Nos. 61475177 and 61621001), the Shanghai Municipal Natural Science Foundation, China (Grant No. 13ZR1446100), and the MDE Key Laboratory of Advanced Micro-Structured Materials.

Configuration management and automatic control of an augmentor wing aircraft with vectored thrust

NASA Technical Reports Server (NTRS)

Cicolani, L. S.; Sridhar, B.; Meyer, G.

1979-01-01

An advanced structure for automatic flight control logic for powered-lift aircraft operating in terminal areas is under investigation at Ames Research Center. This structure is based on acceleration control; acceleration commands are constructed as the sum of acceleration on the reference trajectory and a corrective feedback acceleration to regulate path tracking errors. The central element of the structure, termed a Trimmap, uses a model of the aircraft aerodynamic and engine forces to calculate the control settings required to generate the acceleration commands. This report describes the design criteria for the Trimmap and derives a Trimmap for Ames experimental augmentor wing jet STOL research aircraft.

Long-term real-time structural health monitoring using wireless smart sensor

NASA Astrophysics Data System (ADS)

Jang, Shinae; Mensah-Bonsu, Priscilla O.; Li, Jingcheng; Dahal, Sushil

2013-04-01

Improving the safety and security of civil infrastructure has become a critical issue for decades since it plays a central role in the economics and politics of a modern society. Structural health monitoring of civil infrastructure using wireless smart sensor network has emerged as a promising solution recently to increase structural reliability, enhance inspection quality, and reduce maintenance costs. Though hardware and software framework are well prepared for wireless smart sensors, the long-term real-time health monitoring strategy are still not available due to the lack of systematic interface. In this paper, the Imote2 smart sensor platform is employed, and a graphical user interface for the long-term real-time structural health monitoring has been developed based on Matlab for the Imote2 platform. This computer-aided engineering platform enables the control, visualization of measured data as well as safety alarm feature based on modal property fluctuation. A new decision making strategy to check the safety is also developed and integrated in this software. Laboratory validation of the computer aided engineering platform for the Imote2 on a truss bridge and a building structure has shown the potential of the interface for long-term real-time structural health monitoring.

Respiratory complex I: 'steam engine' of the cell?

PubMed

Efremov, Rouslan G; Sazanov, Leonid A

2011-08-01

Complex I is the first enzyme of the respiratory chain and plays a central role in cellular energy production. It has been implicated in many human neurodegenerative diseases, as well as in ageing. One of the biggest membrane protein complexes, it is an L-shaped assembly consisting of hydrophilic and membrane domains. Previously, we have determined structures of the hydrophilic domain in several redox states. Last year was marked by fascinating breakthroughs in the understanding of the complete structure. We described the architecture of the membrane domain and of the entire bacterial complex I. X-ray analysis of the larger mitochondrial enzyme has also been published. The core subunits of the bacterial and mitochondrial enzymes have remarkably similar structures. The proposed mechanism of coupling between electron transfer and proton translocation involves long-range conformational changes, coordinated in part by a long α-helix, akin to the coupling rod of a steam engine. Copyright © 2011 Elsevier Ltd. All rights reserved.

Giant surfactants provide a versatile platform for sub-10-nm nanostructure engineering

PubMed Central

Yu, Xinfei; Yue, Kan; Hsieh, I-Fan; Li, Yiwen; Dong, Xue-Hui; Liu, Chang; Xin, Yu; Wang, Hsiao-Fang; Shi, An-Chang; Newkome, George R.; Chen, Er-Qiang; Zhang, Wen-Bin; Cheng, Stephen Z. D.

2013-01-01

The engineering of structures across different length scales is central to the design of novel materials with controlled macroscopic properties. Herein, we introduce a unique class of self-assembling materials, which are built upon shape- and volume-persistent molecular nanoparticles and other structural motifs, such as polymers, and can be viewed as a size-amplified version of the corresponding small-molecule counterparts. Among them, “giant surfactants” with precise molecular structures have been synthesized by “clicking” compact and polar molecular nanoparticles to flexible polymer tails of various composition and architecture at specific sites. Capturing the structural features of small-molecule surfactants but possessing much larger sizes, giant surfactants bridge the gap between small-molecule surfactants and block copolymers and demonstrate a duality of both materials in terms of their self-assembly behaviors. The controlled structural variations of these giant surfactants through precision synthesis further reveal that their self-assemblies are remarkably sensitive to primary chemical structures, leading to highly diverse, thermodynamically stable nanostructures with feature sizes around 10 nm or smaller in the bulk, thin-film, and solution states, as dictated by the collective physical interactions and geometric constraints. The results suggest that this class of materials provides a versatile platform for engineering nanostructures with sub-10-nm feature sizes. These findings are not only scientifically intriguing in understanding the chemical and physical principles of the self-assembly, but also technologically relevant, such as in nanopatterning technology and microelectronics. PMID:23716680

Digital system for structural dynamics simulation

NASA Technical Reports Server (NTRS)

Krauter, A. I.; Lagace, L. J.; Wojnar, M. K.; Glor, C.

1982-01-01

State-of-the-art digital hardware and software for the simulation of complex structural dynamic interactions, such as those which occur in rotating structures (engine systems). System were incorporated in a designed to use an array of processors in which the computation for each physical subelement or functional subsystem would be assigned to a single specific processor in the simulator. These node processors are microprogrammed bit-slice microcomputers which function autonomously and can communicate with each other and a central control minicomputer over parallel digital lines. Inter-processor nearest neighbor communications busses pass the constants which represent physical constraints and boundary conditions. The node processors are connected to the six nearest neighbor node processors to simulate the actual physical interface of real substructures. Computer generated finite element mesh and force models can be developed with the aid of the central control minicomputer. The control computer also oversees the animation of a graphics display system, disk-based mass storage along with the individual processing elements.

Collaborative Writing in Engineering: Perspectives from Research and Implications for Undergraduate Education

ERIC Educational Resources Information Center

Gimenez, J.; Thondhlana, J.

2012-01-01

In engineering, like in many other disciplines, collaborative writing (CW) has been identified as a central practice in both the academy and industry. A number of studies have shown that both students and professionals in this field write most discipline-specific genres collaboratively. Despite its centrality, CW in engineering is still an…

CENTRAL ENGINE MEMORY OF GAMMA-RAY BURSTS AND SOFT GAMMA-RAY REPEATERS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Bin-Bin; Castro-Tirado, Alberto J.; Zhang, Bing, E-mail: zhang.grb@gmail.com

Gamma-ray bursts (GRBs) are bursts of γ-rays generated from relativistic jets launched from catastrophic events such as massive star core collapse or binary compact star coalescence. Previous studies suggested that GRB emission is erratic, with no noticeable memory in the central engine. Here we report a discovery that similar light curve patterns exist within individual bursts for at least some GRBs. Applying the Dynamic Time Warping method, we show that similarity of light curve patterns between pulses of a single burst or between the light curves of a GRB and its X-ray flare can be identified. This suggests that themore » central engine of at least some GRBs carries “memory” of its activities. We also show that the same technique can identify memory-like emission episodes in the flaring emission in soft gamma-ray repeaters (SGRs), which are believed to be Galactic, highly magnetized neutron stars named magnetars. Such a phenomenon challenges the standard black hole central engine models for GRBs, and suggest a common physical mechanism behind GRBs and SGRs, which points toward a magnetar central engine of GRBs.« less

The central equipment pool, an opportunity for improved technology management.

PubMed

Gentles, W M

2000-01-01

A model for a central equipment pool managed by a clinical engineering department has been presented. The advantages to patient care and to the clinical engineering department are many. The distribution of portable technology that has been traditionally managed by the materials management function is a logical match to the expanding role of clinical engineering departments in technology management. Accurate asset management tools have allowed us to provide reliable measures of infusion pump utilization, permitting us to predict future needs as programs expand. Thus we are more actively involved in strategic technology planning. The central equipment pool is an excellent opportunity for the clinical engineering department to increase its technology management activities.

Structure of an agonist-bound ionotropic glutamate receptor.

PubMed

Yelshanskaya, Maria V; Li, Minfen; Sobolevsky, Alexander I

2014-08-29

Ionotropic glutamate receptors (iGluRs) mediate most excitatory neurotransmission in the central nervous system and function by opening their ion channel in response to binding of agonist glutamate. Here, we report a structure of a homotetrameric rat GluA2 receptor in complex with partial agonist (S)-5-nitrowillardiine. Comparison of this structure with the closed-state structure in complex with competitive antagonist ZK 200775 suggests conformational changes that occur during iGluR gating. Guided by the structures, we engineered disulfide cross-links to probe domain interactions that are important for iGluR gating events. The combination of structural information, kinetic modeling, and biochemical and electrophysiological experiments provides insight into the mechanism of iGluR gating. Copyright © 2014, American Association for the Advancement of Science.

Managing the equipment service life in rendering engineering support to NPP operation

NASA Astrophysics Data System (ADS)

Ryasnyy, S. I.

2015-05-01

Apart from subjecting metal to nondestructive testing and determining its actual state, which are the traditional methods used for managing the service life of NPP equipment during its operation, other approaches closely linked with rendering engineering support to NPP operation have emerged in recent decades, which, however, have been covered in publications to a lesser extent. Service life management matters occupy the central place in the structure of engineering support measures. Application of the concept of repairing NPP equipment based on assessing its technical state and the risk of its failure makes it possible to achieve significantly smaller costs for maintenance and repairs and produce a larger amount of electricity due to shorter planned outages. Decreasing the occurrence probability of a process-related abnormality through its prediction is a further development of techniques for monitoring the technical state of equipment and systems. The proposed and implemented procedure for predicting the occurrence of process-related deviations from normal NPP operation opens the possibility to record in the online mode the trends in changes of process parameters that are likely to lead to malfunctions in equipment operation and to reduce the probability of power unit unloading when an abnormal technical state of equipment occurs and develops by recording changes in the state at an early stage and taking timely corrective measures. The article presents the structure of interconnections between the objectives and conditions of adjustment and commissioning tests, in which the management of equipment service life (saving and optimizing the service life) occupies the central place. Special attention is paid to differences in resource saving and optimization measures.

A NARROW SHORT-DURATION GRB JET FROM A WIDE CENTRAL ENGINE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Duffell, Paul C.; Quataert, Eliot; MacFadyen, Andrew I., E-mail: duffell@berkeley.edu

2015-11-01

We use two-dimensional relativistic hydrodynamic numerical calculations to show that highly collimated relativistic jets can be produced in neutron star merger models of short-duration gamma-ray bursts (GRBs) without the need for a highly directed engine or a large net magnetic flux. Even a hydrodynamic engine generating a very wide sustained outflow on small scales can, in principle, produce a highly collimated relativistic jet, facilitated by a dense surrounding medium that provides a cocoon surrounding the jet core. An oblate geometry to the surrounding gas significantly enhances the collimation process. Previous numerical simulations have shown that the merger of two neutronmore » stars produces an oblate, expanding cloud of dynamical ejecta. We show that this gas can efficiently collimate the central engine power much like the surrounding star does in long-duration GRB models. For typical short-duration GRB central engine parameters, we find jets with opening angles of an order of 10° in which a large fraction of the total outflow power of the central engine resides in highly relativistic material. These results predict large differences in the opening angles of outflows from binary neutron star mergers versus neutron star–black hole mergers.« less

jsc2012e241585

NASA Image and Video Library

2012-12-09

In Baikonur, Kazakhstan, Expedition 34/35 backup crewmembers Luca Parmitano of the European Space Agency (left), Fyodor Yurchikhin (center) and Karen Nyberg of NASA (right) enjoy a meal in a Kazakh yurt Dec. 9, 2012 during a traditional tour of the city. A yurt is a portable, wood-framed dwelling structure that was traditionally used by nomads in the steppes of Central Asia but which is still used for ceremonial celebrations. Prime crewmembers Flight Engineer Tom Marshburn of NASA, Soyuz Commander Roman Romanenko and Flight Engineer Chris Hadfield of the Canadian Space Agency will launch Dec. 19 from the Baikonur Cosmodrome in their Soyuz TMA-07M spacecraft for a five-month mission on the International Space Station. Photo Credit: NASA/Victor Zelentsov

An experimental study of interacting swirl flows in a model gas turbine combustor

NASA Astrophysics Data System (ADS)

Vishwanath, Rahul B.; Tilak, Paidipati Mallikarjuna; Chaudhuri, Swetaprovo

2018-03-01

In this experimental work, we analyze the flow structures emerging from the mutual interaction between adjacent swirling flows at variable degrees of swirl, issued into a semi-confined chamber, as it could happen in a three cup sector of an annular premixed combustor of a modern gas turbine engine. Stereoscopic particle image velocimetry ( sPIV) is used to characterize both the non-reacting and reacting flow fields in the central diametrical (vertical) plane of the swirlers and the corresponding transverse (horizontal) planes at different heights above the swirlers. A central swirling flow with a fixed swirl vane angle is allowed to interact with its neighboring flows of varied swirl levels, with constant inlet bulk flow velocity through the central port. It is found that the presence of straight jets with zero swirl or co-rotating swirling jets with increasing swirl on both sides of the central swirling jet, significantly alters its structures. As such, an increase in the amount of swirl in the neighboring flows increases the recirculation levels in central swirling flow leading to a bubble-type vortex breakdown, not formed otherwise. It is shown with the aid of Helmholtz decomposition that the transition from conical to bubble-type breakdown is captured well by the radial momentum induced by the azimuthal vorticity. Simultaneous sPIV and OH-planar laser-induced fluorescence (PLIF) are employed to identify the influence of the neighboring jets on the reacting vortex breakdown states. Significant changes in the vortex breakdown size and structure are observed due to variation in swirl levels of the neighboring jets alongside reaction and concomitant flow dilatation.

Engineering Manual for McMurdo Station. Revision

DTIC Science & Technology

1979-01-01

1-3 Rock Quarry .. ..... ....... ....... ..... 1-4 . Fast Ice .. ..... ....... ....... ........ 1-4 Snow-Drift Ice Slabs. .. ....... ....... ...... 1...Chapter 6. Fast p.- The Fortress Rocks, about 3,000 feet ice was found beneath the sewage outfall north of the central McMurdo Station structure in DF-71...concrete aggregate tion from the land (Figure 1-11). Drilling has and fill material in the McMurdo area. This also shown the presence of fast ice on the

Blending Education and Polymer Science: Semi Automated Creation of a Thermodynamic Property Database.

PubMed

Tchoua, Roselyne B; Qin, Jian; Audus, Debra J; Chard, Kyle; Foster, Ian T; de Pablo, Juan

2016-09-13

Structured databases of chemical and physical properties play a central role in the everyday research activities of scientists and engineers. In materials science, researchers and engineers turn to these databases to quickly query, compare, and aggregate various properties, thereby allowing for the development or application of new materials. The vast majority of these databases have been generated manually, through decades of labor-intensive harvesting of information from the literature; yet, while there are many examples of commonly used databases, a significant number of important properties remain locked within the tables, figures, and text of publications. The question addressed in our work is whether, and to what extent, the process of data collection can be automated. Students of the physical sciences and engineering are often confronted with the challenge of finding and applying property data from the literature, and a central aspect of their education is to develop the critical skills needed to identify such data and discern their meaning or validity. To address shortcomings associated with automated information extraction, while simultaneously preparing the next generation of scientists for their future endeavors, we developed a novel course-based approach in which students develop skills in polymer chemistry and physics and apply their knowledge by assisting with the semi-automated creation of a thermodynamic property database.

Blending Education and Polymer Science: Semiautomated Creation of a Thermodynamic Property Database

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tchoua, Roselyne B.; Qin, Jian; Audus, Debra J.

Structured databases of chemical and physical properties play a central role in the everyday research activities of scientists and engineers. In materials science, researchers and engineers turn to these databases to quickly query, compare, and aggregate various properties, thereby allowing for the development or application of new materials. The vast majority of these databases have been generated manually, through decades of labor-intensive harvesting of information from the literature, yet while there are many examples of commonly used databases, a significant number of important properties remain locked within the tables, figures, and text of publications. The question addressed in our workmore » is whether and to what extent the process of data collection can be automated. Students of the physical sciences and engineering are often confronted with the challenge of finding and applying property data from the literature, and a central aspect of their education is to develop the critical skills needed to identify such data and discern their meaning or validity. To address shortcomings associated with automated information extraction while simultaneously preparing the next generation of scientists for their future endeavors, we developed a novel course-based approach in which students develop skills in polymer chemistry and physics and apply their knowledge by assisting with the semiautomated creation of a thermodynamic property database.« less

Comparative Flow Path Analysis and Design Assessment of an Axisymmetric Hydrogen Fueled Scramjet Flight Test Engine at a Mach Number of 6.5

NASA Technical Reports Server (NTRS)

McClinton, C.; Rondakov, A.; Semenov, V.; Kopehenov, V.

1991-01-01

NASA has contracted with the Central Institute of Aviation Motors CIAM to perform a flight test and ground test and provide a scramjet engine for ground test in the United States. The objective of this contract is to obtain ground to flight correlation for a supersonic combustion ramjet (scramjet) engine operating point at a Mach number of 6.5. This paper presents results from a flow path performance and thermal evaluation performed on the design proposed by the CIAM. This study shows that the engine will perform in the scramjet mode for stoichiometric operation at a flight Mach number of 6.5. Thermal assessment of the structure indicates that the combustor cooling liner will provide adequate cooling for a Mach number of 6.5 test condition and that optional material proposed by CIAM for the cowl leading-edge design are required to allow operation with or without a type IV shock-shock interaction.

Detection of 183 GHz H2O megamaser emission towards NGC 4945

NASA Astrophysics Data System (ADS)

Humphreys, E. M. L.; Vlemmings, W. H. T.; Impellizzeri, C. M. V.; Galametz, M.; Olberg, M.; Conway, J. E.; Belitsky, V.; De Breuck, C.

2016-08-01

Aims: The aim of this work is to search Seyfert 2 galaxy NGC 4945, a well-known 22 GHz water megamaser galaxy, for H2O (mega)maser emission at 183 GHz. Methods: We used APEX SEPIA Band 5 (an ALMA Band 5 receiver on the APEX telescope) to perform the observations. Results: We detected 183 GHz H2O maser emission towards NGC 4945 with a peak flux density of ~3 Jy near the galactic systemic velocity. The emission spans a velocity range of several hundred km s-1. We estimate an isotropic luminosity of >1000 L⊙, classifying the emission as a megamaser. A comparison of the 183 GHz spectrum with that observed at 22 GHz suggests that 183 GHz emission also arises from the active galactic nucleus (AGN) central engine. If the 183 GHz emission originates from the circumnuclear disk, then we estimate that a redshifted feature at 1084 km s-1 in the spectrum should arise from a distance of 0.022 pc from the supermassive black hole (1.6 × 105 Schwarzschild radii), I.e. closer than the water maser emission previously detected at 22 GHz. This is only the second time 183 GHz maser emission has been detected towards an AGN central engine (the other galaxy being NGC 3079). It is also the strongest extragalactic millimetre/submillimetre water maser detected to date. Conclusions: Strong millimetre 183 GHz H2O maser emission has now been shown to occur in an external galaxy. For NGC 4945, we believe that the maser emission arises, or is dominated by, emission from the AGN central engine. Emission at higher velocity, I.e. for a Keplerian disk closer to the black hole, has been detected at 183 GHz compared with that for the 22 GHz megamaser. This indicates that millimetre/submillimetre H2O masers can indeed be useful for tracing out more of AGN central engine structures and dynamics than previously probed. Future observations using ALMA Band 5 should unequivocally determine the origin of the emission in this and other galaxies.

Exploring the repeat protein universe through computational protein design

DOE PAGES

Brunette, TJ; Parmeggiani, Fabio; Huang, Po-Ssu; ...

2015-12-16

A central question in protein evolution is the extent to which naturally occurring proteins sample the space of folded structures accessible to the polypeptide chain. Repeat proteins composed of multiple tandem copies of a modular structure unit are widespread in nature and have critical roles in molecular recognition, signalling, and other essential biological processes. Naturally occurring repeat proteins have been re-engineered for molecular recognition and modular scaffolding applications. In this paper, we use computational protein design to investigate the space of folded structures that can be generated by tandem repeating a simple helix–loop–helix–loop structural motif. Eighty-three designs with sequences unrelatedmore » to known repeat proteins were experimentally characterized. Of these, 53 are monomeric and stable at 95 °C, and 43 have solution X-ray scattering spectra consistent with the design models. Crystal structures of 15 designs spanning a broad range of curvatures are in close agreement with the design models with root mean square deviations ranging from 0.7 to 2.5 Å. Finally, our results show that existing repeat proteins occupy only a small fraction of the possible repeat protein sequence and structure space and that it is possible to design novel repeat proteins with precisely specified geometries, opening up a wide array of new possibilities for biomolecular engineering.« less

Central-engine-powered Bright X-Ray Flares in Short Gamma-Ray Bursts: A Hint of a Black Hole–Neutron Star Merger?

NASA Astrophysics Data System (ADS)

Mu, Hui-Jun; Gu, Wei-Min; Mao, Jirong; Hou, Shu-Jin; Lin, Da-Bin; Liu, Tong

2018-05-01

Short gamma-ray bursts may originate from the merger of a double neutron star (NS) or the merger of a black hole (BH) and an NS. We propose that the bright X-ray flare related to the central engine reactivity may indicate a BH–NS merger, since such a merger can provide more fallback materials and therefore a more massive accretion disk than the NS–NS merger. Based on the 49 observed short bursts with the Swift/X-ray Telescope follow-up observations, we find that three bursts have bright X-ray flares, among which three flares from two bursts are probably related to the central engine reactivity. We argue that these two bursts may originate from the BH–NS merger rather than the NS–NS merger. Our suggested link between the central-engine-powered bright X-ray flare and the BH–NS merger event can be checked by future gravitational wave detections from advanced LIGO and Virgo.

THE BLACK HOLE CENTRAL ENGINE FOR ULTRA-LONG GAMMA-RAY BURST 111209A AND ITS ASSOCIATED SUPERNOVA 2011KL

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gao, He; You, Zhi-Qiang; Lei, Wei-Hua

Recently, the first association between an ultra-long gamma-ray burst (GRB) and a supernova was reported, i.e., GRB 111209A/SN 2011kl, enabling us to investigate the physics of central engines or even progenitors for ultra-long GRBs. In this paper, we inspect the broadband data of GRB 111209A/SN 2011kl. The late-time X-ray light curve exhibits a GRB 121027A-like fallback bump, suggesting a black hole (BH) central engine. We thus propose a collapsar model with fallback accretion for GRB 111209A/SN 2011kl. The required model parameters, such as the total mass and radius of the progenitor star, suggest that the progenitor of GRB 111209A ismore » more likely a Wolf–Rayet star instead of a blue supergiant, and the central engine of this ultra-long burst is a BH. The implications of our results are discussed.« less

Conception and development of the Second Life® Embryo Physics Course.

PubMed

Gordon, Richard

2013-06-01

The study of embryos with the tools and mindset of physics, started by Wilhelm His in the 1880s, has resumed after a hiatus of a century. The Embryo Physics Course convenes online allowing interested researchers and students, who are scattered around the world, to gather weekly in one place, the virtual world of Second Life®. It attracts people from a wide variety of disciplines and walks of life: applied mathematics, artificial life, bioengineering, biophysics, cancer biology, cellular automata, civil engineering, computer science, embryology, electrical engineering, evolution, finite element methods, history of biology, human genetics, mathematics, molecular developmental biology, molecular biology, nanotechnology, philosophy of biology, phycology, physics, self-reproducing systems, stem cells, tensegrity structures, theoretical biology, and tissue engineering. Now in its fifth year, the Embryo Physics Course provides a focus for research on the central question of how an embryo builds itself.

Theoretical and Observational Studies of the Central Engines of AGN

NASA Technical Reports Server (NTRS)

Sivron, Ran

1995-01-01

In Active Galactic Nuclei (AGN) the luminosity is so intense that the effect of radiation pressure on a particle may exceed the gravitational attraction. It was shown that when such luminosities are reached, relatively cold (not completely ionized) thermal matter clouds may form in the central engines of AGN, where most of the luminosity originates. We show that the spectrum of emission from cold clouds embedded in hot relativistic matter is similar to the observed spectrum. We also show that within the hot relativistic matter, cold matter moves faster than the speed of sound or the Alfven speed, and shocks form. The shocks provide a mechanism by which a localized perturbation can propagate throughout the central engine. The shocked matter can emit the observed luminosity, and can explain the flux and spectral variability. It may also provide an efficient mechanism for the outward transfer of angular momentum and provide the outward flow of winds. With observations from X-ray satellites, emission features from the cold and hot matter may be revealed. Our analysis of X-ray data from the Seyfert 1 galaxy MCG - 6-30-15 over five years using detectors on the Ginga and Rosat satellites, revealed some interesting variable features. A source with hot matter emits non-thermal radiation which is Compton reflected from cold matter and then absorbed by warm (partially ionized) absorbing matter in the first model, which can be fit to the data if both the cold and warm absorbers are near the central engine. An alternative model in which the emission from the hot matter is partially covered by very warm matter (in which all elements except Iron are mostly ionized) is also successful. In this model the cold and warm matter may be at distances of up to 100 times the size of the central engine, well within the region where broad optical lines are produced. The flux variability is more naturally explained by the second model. Our results support the existence of cold matter in, or near, the central engine of MCG -6-30-15. Cold matter in the central engine, and evidence of the effects of shocks, is probably forthcoming with future X-ray satellites.

Transient Dissipation and Structural Costs of Physical Information Transduction

NASA Astrophysics Data System (ADS)

Boyd, Alexander B.; Mandal, Dibyendu; Riechers, Paul M.; Crutchfield, James P.

2017-06-01

A central result that arose in applying information theory to the stochastic thermodynamics of nonlinear dynamical systems is the information-processing second law (IPSL): the physical entropy of the Universe can decrease if compensated by the Shannon-Kolmogorov-Sinai entropy change of appropriate information-carrying degrees of freedom. In particular, the asymptotic-rate IPSL precisely delineates the thermodynamic functioning of autonomous Maxwellian demons and information engines. How do these systems begin to function as engines, Landauer erasers, and error correctors? We identify a minimal, and thus inescapable, transient dissipation of physical information processing, which is not captured by asymptotic rates, but is critical to adaptive thermodynamic processes such as those found in biological systems. A component of transient dissipation, we also identify an implementation-dependent cost that varies from one physical substrate to another for the same information processing task. Applying these results to producing structured patterns from a structureless information reservoir, we show that "retrodictive" generators achieve the minimal costs. The results establish the thermodynamic toll imposed by a physical system's structure as it comes to optimally transduce information.

Ground-water areas and well logs, central Sevier Valley, Utah

USGS Publications Warehouse

Young, Richard A.

1960-01-01

Between September 1959 and June 1960 the United States Geological Survey and the Utah State Engineer, with financial assistance from Garfield, Millard, Piute, Sanpete, and Sevier Counties and from local water-users’ associations, cooperated in an investigation to determine the structural framework of the central Sevier Valley and to evaluate the valley’s ground-water potential. An important aspect of the study was the drilling of 22 test holes under private contract. These data and other data collected during the course of the larger ground-water investigation of which the test drilling was a part will be evaluated in a report on the geology and ground-water resources of the central Sevier Valley. The present report has been prepared to make available the logs of test holes and to describe in general terms the availability of ground water in the different areas of the valley.

Into the Second Century: Memphis Engineer District, 1976-1981

DTIC Science & Technology

1983-01-01

stream out of Lake Itasca in central Minnesota, the river begins a 2,340-mile journey to the Gulf of Mexico. In making the long journey, the river...McKellar Lake in honor of the senior Senator from Tennessee, Kenneth D. McKellar. Part of Tennessee Chute was dredged and then used as a slack...Missouri; and the Reelfoot -Obion areas in west Tennessee to monitor flood control structures. Under Phase I operations the Memphis District provided

Nanotechnology applications and approaches for neuroregeneration and drug delivery to the central nervous system.

PubMed

Silva, Gabriel A

2010-06-01

Nanotechnology is the science and engineering concerned with the design, synthesis, and characterization of materials and devices that have a functional organization in at least one dimension on the nanometer (i.e., one billionth of a meter) scale. The potential impact of bottom up self-assembling nanotechnology, custom made molecules that self-assemble or self-organize into higher ordered structures in response to a defined chemical or physical cue, and top down lithographic type technologies where detail is engineered at smaller scales starting from bulk materials, stems from the fact that these nanoengineered materials and devices exhibit emergent mesocale and macroscale chemical and physical properties that are often different than their constituent nanoscale building block molecules or materials. As such, applications of nanotechnology to medicine and biology allow the interaction and integration of cells and tissues with nanoengineered substrates at a molecular (i.e., subcellular) level with a very high degree of functional specificity and control. This review considers applications of nanotechnology aimed at the neuroprotection and functional regeneration of the central nervous system (CNS) following traumatic or degenerative insults, and nanotechnology approaches for delivering drugs and other small molecules across the blood-brain barrier. It also discusses developing platform technologies that may prove to have broad applications to medicine and physiology, including some being developed for rescuing or replacing anatomical and/or functional CNS structures.

Multivariate assessment of the central-cardiorespiratory network structure in neuropathological disease.

PubMed

Schulz, Steffen; Haueisen, Jens; Bär, Karl-Juergen; Voss, Andreas

2018-06-22

The new interdisciplinary field of network physiology is getting more and more into the focus of interest in medicine. The autonomic nervous system (ANS) dysfunction is well described in schizophrenia (SZO). However, the linear and nonlinear coupling between the ANS and central nervous system (CNS) is only partly addressed until now. This coupling can be assumed as a feedback-feedforward network, reacting with flexible and adaptive responses to internal and external factors. Approach: For the first time, in this study, we investigated linear and nonlinear short-term central-cardiorespiratory couplings of 17 patients suffering from paranoid schizophrenia (SZO) in comparison to 17 age-gender matched healthy subjects (CON) analyzing heart rate (HR), respiration (RESP) and the power of frontal EEG activity (PEEG). The objective is to determine how the different regulatory aspects of the CNS-ANS compose the central-cardiorespiratory network (CCRN). To quantify these couplings within the CCRN the normalized short time partial directed coherence (NSTPDC) and the new multivariate high-resolution joint symbolic dynamics (mHRJSD) were applied. Main results: We found that the CCRN in SZO is characterized as a bidirectional one, with stronger central driving mechanisms (PEEG→HR) towards HR regulation than vice versa, and with stronger respiratory influence (RESP→PEEG) on central activity than vice versa. This suggests that the central-cardiorespiratory process (closed-loop) is mainly focusing on adapting the HR via the sinoatrial node than focusing on respiratory regulation. On the other side, the feedback-loop from ANS to CNS is strongly dominated via respiratory activity. Significance: We could demonstrate a considerably significantly different central-cardiorespiratory network structure in schizophrenia with strong central influence on the cardiac system and a strong respiratory influence on the central nervous system. Moreover, this study provides a more in-depth understanding of the interplay of the central and autonomic regulatory network in healthy subjects and schizophrenic patients. . © 2018 Institute of Physics and Engineering in Medicine.

Engine Research Building’s Central Control Room

NASA Image and Video Library

1948-07-21

Operators in the Engine Research Building’s Central Control Room at the National Advisory Committee for Aeronautics (NACA) Lewis Flight Propulsion Laboratory. The massive 4.25-acre Engine Research Building contains dozens of test cells, test stands, and altitude chambers. A powerful collection of compressors and exhausters located in the central portion of the basement provided process air and exhaust for these test areas. This system is connected to similar process air systems in the laboratory’s other large test facilities. The Central Control Room coordinates this activity and communicates with the local utilities. This photograph was taken just after a major upgrade to the control room in 1948. The panels on the wall contain rudimentary floor plans of the different Engine Research Building sections with indicator lights and instrumentation for each test cell. The process air equipment included 12 exhausters, four compressors, a refrigeration system, cooling water, and an exhaust system. The operators in the control room kept in contact with engineers running the process air system and those conducting the tests in the test cells. The operators also coordinated with the local power companies to make sure enough electricity was available to operate the powerful compressors and exhausters.

Standardized Fault-Tolerant Sensing Nodes for an Intelligent Turbine Engine Control System (Preprint)

DTIC Science & Technology

2013-05-01

representation of a centralized control system on a turbine engine. All actuators and sensors are point-to-point cabled to the controller ( FADEC ) which...electronics themselves. Figure 1: Centralized Control System Each function resides within the FADEC and uses Unique Point-to-Point Analog...distributed control system on the same turbine engine. The actuators and sensors interface to Smart Nodes which, in turn communicate to the FADEC via

A comparative study on book shelf structure based on different domain modal analysis

NASA Astrophysics Data System (ADS)

Sabamehr, Ardalan; Roy, Timir Baran; Bagchi, Ashutosh

2017-04-01

Structural Health Monitoring (SHM) based on the vibration of structures has been very attractive topic for researchers in different fields such as: civil, aeronautical and mechanical engineering. The aim of this paper is to compare three most common modal identification techniques such as Frequency Domain Decomposition (FDD), Stochastic Subspace Identification (SSI) and Continuous Wavelet Transform (CWT) to find modal properties (such as natural frequency, mode shape and damping ratio) of three story book shelf steel structure which was built in Concordia University Lab. The modified Complex Morlet wavelet have been selected for wavelet in order to use asymptotic signal rather than real one with variable bandwidth and wavelet central frequency. So, CWT is able to detect instantaneous modulus and phase by use of local maxima ridge detection.

Opportunities and challenges for the sustainable production of structurally complex diterpenoids in recombinant microbial systems.

PubMed

Kemper, Katarina; Hirte, Max; Reinbold, Markus; Fuchs, Monika; Brück, Thomas

2017-01-01

With over 50.000 identified compounds terpenes are the largest and most structurally diverse group of natural products. They are ubiquitous in bacteria, plants, animals and fungi, conducting several biological functions such as cell wall components or defense mechanisms. Industrial applications entail among others pharmaceuticals, food additives, vitamins, fragrances, fuels and fuel additives. Central building blocks of all terpenes are the isoprenoid compounds isopentenyl diphosphate and dimethylallyl diphosphate. Bacteria like Escherichia coli harbor a native metabolic pathway for these isoprenoids that is quite amenable for genetic engineering. Together with recombinant terpene biosynthesis modules, they are very suitable hosts for heterologous production of high value terpenes. Yet, in contrast to the number of extracted and characterized terpenes, little is known about the specific biosynthetic enzymes that are involved especially in the formation of highly functionalized compounds. Novel approaches discussed in this review include metabolic engineering as well as site-directed mutagenesis to expand the natural terpene landscape. Focusing mainly on the validation of successful integration of engineered biosynthetic pathways into optimized terpene producing Escherichia coli , this review shall give an insight in recent progresses regarding manipulation of mostly diterpene synthases.

The Structure of Active Galactic Nuclei

NASA Technical Reports Server (NTRS)

Kriss, Gerard A.

1997-01-01

We are continuing our systematic investigation of the nuclear structure of nearby active galactic nuclei (AGN). Upon completion, our study will characterize hypothetical constructs such as narrow-line clouds, obscuring tori, nuclear gas disks. and central black holes with physical measurements for a complete sample of nearby AGN. The major scientific goals of our program are: (1) the morphology of the NLR; (2) the physical conditions and dynamics of individual clouds in the NLR; (3) the structure and physical conditions of the warm reflecting gas; (4) the structure of the obscuring torus; (5) the population and morphology of nuclear disks/tori in AGN; (6) the physical conditions in nuclear disks; and (7) the masses of central black holes in AGN. We will use the Hubble Space Telescope (HST) to obtain high-resolution images and spatially resolved spectra. Far-UV spectroscopy of emission and absorption in the nuclear regions using HST/FOS and the Hopkins Ultraviolet Telescope (HUT) will help establish physical conditions in the absorbing and emitting gas. By correlating the dynamics and physical conditions of the gas with the morphology revealed through our imaging program, we will be able to examine mechanisms for fueling the central engine and transporting angular momentum. The kinematics of the nuclear gas disks may enable us to measure the mass of the central black hole. Contemporaneous X-ray observations using ASCA will further constrain the ionization structure of any absorbing material. Monitoring of variability in the UV and X-ray absorption will be used to determine the location of the absorbing gas, possibly in the outflowing warm reflecting gas, or the broad-line region, or the atmosphere of the obscuring torus. Supporting ground-based observations in the optical, near-IR, imaging polarimetry, and the radio will complete our picture of the nuclear structures. With a comprehensive survey of these characteristics in a complete sample of nearby AGN, our conclusions should be more reliably extended to AGN as a class.

Probabilistic Structural Analysis Theory Development

NASA Technical Reports Server (NTRS)

Burnside, O. H.

1985-01-01

The objective of the Probabilistic Structural Analysis Methods (PSAM) project is to develop analysis techniques and computer programs for predicting the probabilistic response of critical structural components for current and future space propulsion systems. This technology will play a central role in establishing system performance and durability. The first year's technical activity is concentrating on probabilistic finite element formulation strategy and code development. Work is also in progress to survey critical materials and space shuttle mian engine components. The probabilistic finite element computer program NESSUS (Numerical Evaluation of Stochastic Structures Under Stress) is being developed. The final probabilistic code will have, in the general case, the capability of performing nonlinear dynamic of stochastic structures. It is the goal of the approximate methods effort to increase problem solving efficiency relative to finite element methods by using energy methods to generate trial solutions which satisfy the structural boundary conditions. These approximate methods will be less computer intensive relative to the finite element approach.

Hybrid multiphoton volumetric functional imaging of large-scale bioengineered neuronal networks

NASA Astrophysics Data System (ADS)

Dana, Hod; Marom, Anat; Paluch, Shir; Dvorkin, Roman; Brosh, Inbar; Shoham, Shy

2014-06-01

Planar neural networks and interfaces serve as versatile in vitro models of central nervous system physiology, but adaptations of related methods to three dimensions (3D) have met with limited success. Here, we demonstrate for the first time volumetric functional imaging in a bioengineered neural tissue growing in a transparent hydrogel with cortical cellular and synaptic densities, by introducing complementary new developments in nonlinear microscopy and neural tissue engineering. Our system uses a novel hybrid multiphoton microscope design combining a 3D scanning-line temporal-focusing subsystem and a conventional laser-scanning multiphoton microscope to provide functional and structural volumetric imaging capabilities: dense microscopic 3D sampling at tens of volumes per second of structures with mm-scale dimensions containing a network of over 1,000 developing cells with complex spontaneous activity patterns. These developments open new opportunities for large-scale neuronal interfacing and for applications of 3D engineered networks ranging from basic neuroscience to the screening of neuroactive substances.

Ultra-high resolution four dimensional geodetic imaging of engineered structures for stability assessment

USGS Publications Warehouse

Bawden, Gerald W.; Bond, Sandra; Podoski, J. H.; Kreylos, O.; Kellogg, L. H.

2012-01-01

We used ground-based Tripod LiDAR (T-LiDAR) to assess the stability of two engineered structures: a bridge spanning the San Andreas fault following the M6.0 Parkfield earthquake in Central California and a newly built coastal breakwater located at the Kaumālapa`u Harbor Lana'i, Hawaii. In the 10 weeks following the earthquake, we found that the surface under the bridge shifted 7.1 cm with an additional 2.6 cm of motion in the subsequent 13 weeks, which deflected the bridge's northern I-beam support 4.3 cm and 2.1 respectively; the bridge integrity remained intact. T-LiDAR imagery was collected after the completion of armored breakwater with 817 35-ton interlocking concrete armor units, Core-Locs®, in the summers of 2007, 2008 and 2010. We found a wide range of motion of individual Core-Locs, from a few centimeters to >110 cm along the ocean side of the breakwater, with lesser movement along the harbor side.

Introduction: seismology and earthquake engineering in Central and South America.

USGS Publications Warehouse

Espinosa, A.F.

1983-01-01

Reports the state-of-the-art in seismology and earthquake engineering that is being advanced in Central and South America. Provides basic information on seismological station locations in Latin America and some of the programmes in strong-motion seismology, as well as some of the organizations involved in these activities.-from Author

Central Control Room in the Engine Research Building

NASA Image and Video Library

1968-11-21

Operators in the Engine Research Building’s Central Control Room at the National Aeronautics and Space Administration (NASA) Lewis Research Center. The massive 4.25-acre Engine Research Building contains dozens of test cells, test stands, and altitude chambers. A powerful a collection of compressors and exhausters located in the central portion of the basement provides process air and exhaust for these test areas. This system is connected to similar process air systems in the laboratory’s other large test facilities. The Central Control Room coordinates this activity and communicates with the local utilities. The panels on the wall contain schematics with indicator lights and instrumentation for the atmospheric exhaust, altitude exhaust, refrigerated air, and process air systems. The process air equipment included twelve exhausters, four compressors, refrigeration system, cooling water, and an exhaust system. The operators in the control room kept in contact with engineers running the process air system and those conducting the tests in the test cells. The operators also coordinated with the local power companies to make sure enough electricity was available to operate the powerful compressors and exhausters.

1. VIEW OF SUPERINTENDENT'S HOUSE ON ROUTE 29, LOOKING SOUTHWEST. ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. VIEW OF SUPERINTENDENT'S HOUSE ON ROUTE 29, LOOKING SOUTHWEST. THIS TWO-STORY, HIPPED-ROOF STRUCTURE WITH A CENTRAL HALL AND CHIMNEY WAS CONSTRUCTED FOR THE SUPERINTENDENT OF STARK MILL, NEW ENGLAND SOUTHERN MILLS IN 1923-24. THE MILL ENGINEERS, LOCKWOOD GREENE COMPANY, ALSO DESIGNED AND BUILT THE NEW MILL HOUSING. THIS HOUSE HAS SEVEN ROOMS, BATH, SCREENED OUTSIDE PORCH AND SLEEPING PORCH, AND GARAGE. IT COST APPROXIMATELY $9,000. - Superintendent's House, Southwest corner of Routes 29 & 100, Hogansville, Troup County, GA

Vascularized Bone Tissue Engineering: Approaches for Potential Improvement

PubMed Central

Nguyen, Lonnissa H.; Annabi, Nasim; Nikkhah, Mehdi; Bae, Hojae; Binan, Loïc; Park, Sangwon; Kang, Yunqing

2012-01-01

Significant advances have been made in bone tissue engineering (TE) in the past decade. However, classical bone TE strategies have been hampered mainly due to the lack of vascularization within the engineered bone constructs, resulting in poor implant survival and integration. In an effort toward clinical success of engineered constructs, new TE concepts have arisen to develop bone substitutes that potentially mimic native bone tissue structure and function. Large tissue replacements have failed in the past due to the slow penetration of the host vasculature, leading to necrosis at the central region of the engineered tissues. For this reason, multiple microscale strategies have been developed to induce and incorporate vascular networks within engineered bone constructs before implantation in order to achieve successful integration with the host tissue. Previous attempts to engineer vascularized bone tissue only focused on the effect of a single component among the three main components of TE (scaffold, cells, or signaling cues) and have only achieved limited success. However, with efforts to improve the engineered bone tissue substitutes, bone TE approaches have become more complex by combining multiple strategies simultaneously. The driving force behind combining various TE strategies is to produce bone replacements that more closely recapitulate human physiology. Here, we review and discuss the limitations of current bone TE approaches and possible strategies to improve vascularization in bone tissue substitutes. PMID:22765012

Adiabatic expansion, early X-ray data and the central engine in GRBs

NASA Astrophysics Data System (ADS)

Barniol Duran, R.; Kumar, P.

2009-05-01

The Swift satellite early X-ray data show a very steep decay in most of the gamma-ray bursts light curves. This decay is either produced by the rapidly declining continuation of the central engine activity or by some leftover radiation starting right after the central engine shuts off. The latter scenario consists of the emission from an `ember' that cools via adiabatic expansion and, if the jet angle is larger than the inverse of the source Lorentz factor, the large angle emission. In this work, we calculate the temporal and spectral properties of the emission from such a cooling ember, providing a new treatment for the microphysics of the adiabatic expansion. We use the adiabatic invariance of p2⊥/B (p⊥ is the component of the electrons' momentum normal to the magnetic field, B) to calculate the electrons' Lorentz factor during the adiabatic expansion; the electron momentum becomes more and more aligned with the local magnetic field as the expansion develops. We compare the theoretical expectations of the adiabatic expansion (and the large angle emission) with the current observations of the early X-ray data and find that only ~20 per cent of our sample of 107 bursts are potentially consistent with this model. This leads us to believe that, for most bursts, the central engine does not turn off completely during the steep decay of the X-ray light curve; therefore, this phase is produced by the continued rapidly declining activity of the central engine.

24. Photocopy of engineering drawing, May, 1941 (original drawing located ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

24. Photocopy of engineering drawing, May, 1941 (original drawing located at Fairchild Air Force Base, Civil Engineering Building, Civil Engineering vault). ENGINE TEST CELL BUILDING. ELEVATIONS, CENTRAL PORTION AND TEST CELLS 1-4. - Fairchild Air Force Base, Engine Test Cell Building, Near intersection of Arnold Street & George Avenue, Spokane, Spokane County, WA

26. Photocopy of engineering drawing, May, 1941 (original drawing located ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

26. Photocopy of engineering drawing, May, 1941 (original drawing located at Fairchild Air Force Base, Civil Engineering Building, Civil Engineering vault). ENGINE TEST CELL BUILDING. CROSS-SECTION, CENTRAL PORTION AND TEST CELLS 1-4. - Fairchild Air Force Base, Engine Test Cell Building, Near intersection of Arnold Street & George Avenue, Spokane, Spokane County, WA

29. Photocopy of engineering drawing, May, 1941 (original drawing located ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

29. Photocopy of engineering drawing, May, 1941 (original drawing located at Fairchild Air Force Base, Civil Engineering Building, Civil Engineering vault). ENGINE TEST CELL BUILDING. 19508 RENOVATION OF FIRST FLOOR, CENTRAL PORTION. - Fairchild Air Force Base, Engine Test Cell Building, Near intersection of Arnold Street & George Avenue, Spokane, Spokane County, WA

Lyceum: A Multi-Protocol Digital Library Gateway

NASA Technical Reports Server (NTRS)

Maa, Ming-Hokng; Nelson, Michael L.; Esler, Sandra L.

1997-01-01

Lyceum is a prototype scalable query gateway that provides a logically central interface to multi-protocol and physically distributed, digital libraries of scientific and technical information. Lyceum processes queries to multiple syntactically distinct search engines used by various distributed information servers from a single logically central interface without modification of the remote search engines. A working prototype (http://www.larc.nasa.gov/lyceum/) demonstrates the capabilities, potentials, and advantages of this type of meta-search engine by providing access to over 50 servers covering over 20 disciplines.

Mathematical modelling of skeletal repair.

PubMed

MacArthur, B D; Please, C P; Taylor, M; Oreffo, R O C

2004-01-23

Tissue engineering offers significant promise as a viable alternative to current clinical strategies for replacement of damaged tissue as a consequence of disease or trauma. Since mathematical modelling is a valuable tool in the analysis of complex systems, appropriate use of mathematical models has tremendous potential for advancing the understanding of the physical processes involved in such tissue reconstruction. In this review, the potential benefits, and limitations, of theoretical modelling in tissue engineering applications are examined with specific emphasis on tissue engineering of bone. A central tissue engineering approach is the in vivo implantation of a biomimetic scaffold seeded with an appropriate population of stem or progenitor cells. This review will therefore consider the theory behind a number of key factors affecting the success of such a strategy including: stem cell or progenitor population expansion and differentiation ex vivo; cell adhesion and migration, and the effective design of scaffolds; and delivery of nutrient to avascular structures. The focus will be on current work in this area, as well as on highlighting limitations and suggesting possible directions for future work to advance health-care for all.

Propulsion system performance resulting from an integrated flight/propulsion control design

NASA Technical Reports Server (NTRS)

Mattern, Duane; Garg, Sanjay

1992-01-01

Propulsion-system-specific results are presented from the application of the integrated methodology for propulsion and airframe control (IMPAC) design approach to integrated flight/propulsion control design for a 'short takeoff and vertical landing' (STOVL) aircraft in transition flight. The IMPAC method is briefly discussed and the propulsion system specifications for the integrated control design are examined. The structure of a linear engine controller that results from partitioning a linear centralized controller is discussed. The details of a nonlinear propulsion control system are presented, including a scheme to protect the engine operational limits: the fan surge margin and the acceleration/deceleration schedule that limits the fuel flow. Also, a simple but effective multivariable integrator windup protection scheme is examined. Nonlinear closed-loop simulation results are presented for two typical pilot commands for transition flight: acceleration while maintaining flightpath angle and a change in flightpath angle while maintaining airspeed. The simulation nonlinearities include the airframe/engine coupling, the actuator and sensor dynamics and limits, the protection scheme for the engine operational limits, and the integrator windup protection. Satisfactory performance of the total airframe plus engine system for transition flight, as defined by the specifications, was maintained during the limit operation of the closed-loop engine subsystem.

18. Photocopy of engineering drawing, May, 1941 (original drawing located ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

18. Photocopy of engineering drawing, May, 1941 (original drawing located at Fairchild Air Force Base, Civil Engineering Building, Civil Engineering vault). ENGINE TEST CELL BUILDING. FIRST FLOOR PLAN, CENTRAL PORTION AND TEST CELLS 1-4. - Fairchild Air Force Base, Engine Test Cell Building, Near intersection of Arnold Street & George Avenue, Spokane, Spokane County, WA

22. Photocopy of engineering drawing, May, 1941 (original drawing located ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

22. Photocopy of engineering drawing, May, 1941 (original drawing located at Fairchild Air Force Base, Civil Engineering Building, Civil Engineering vault). ENGINE TEST CELL BUILDING. THIRD FLOOR AND ROOF PLAN, CENTRAL PORTION AND TEST CELLS 1-4. - Fairchild Air Force Base, Engine Test Cell Building, Near intersection of Arnold Street & George Avenue, Spokane, Spokane County, WA

16. Photocopy of engineering drawing, May, 1941 (original drawing located ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

16. Photocopy of engineering drawing, May, 1941 (original drawing located at Fairchild Air Force Base, Civil Engineering Building, Civil Engineering vault). ENGINE TEST CELL BUILDING. BASEMENT FLOOR PLAN, CENTRAL PORTION AND TEST CELLS 1-4. - Fairchild Air Force Base, Engine Test Cell Building, Near intersection of Arnold Street & George Avenue, Spokane, Spokane County, WA

20. Photocopy of engineering drawing, May, 1941 (original drawing located ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

20. Photocopy of engineering drawing, May, 1941 (original drawing located at Fairchild Air Force Base, Civil Engineering Building, Civil Engineering vault). ENGINE TEST CELL BUILDING. SECOND FLOOR PLAN, CENTRAL PORTION AND TEST CELLS 1-4. - Fairchild Air Force Base, Engine Test Cell Building, Near intersection of Arnold Street & George Avenue, Spokane, Spokane County, WA

Engineered disc-like angle-ply structures for intervertebral disc replacement.

PubMed

Nerurkar, Nandan L; Sen, Sounok; Huang, Alice H; Elliott, Dawn M; Mauck, Robert L

2010-04-15

To develop a construction algorithm in which electrospun nanofibrous scaffolds are coupled with a biocompatible hydrogel to engineer a mesenchymal stem cell (MSC)-based disc replacement. To engineer a disc-like angle-ply structure (DAPS) that replicates the multiscale architecture of the intervertebral disc. Successful engineering of a replacement for the intervertebral disc requires replication of its mechanical function and anatomic form. Despite many attempts to engineer a replacement for ailing and degenerated discs, no prior study has replicated the multiscale hierarchical architecture of the native disc, and very few have assessed the mechanical function of formed neo-tissues. A new algorithm for the construction of a disc analogue was developed, using agarose to form a central nucleus pulposus (NP) and oriented electrospun nanofibrous scaffolds to form the anulus fibrosus region (AF). Bovine MSCs were seeded into both regions and biochemical, histologic, and mechanical maturation were evaluated with in vitro culture. We show that mechanical testing in compression and torsion, loading methods commonly used to assess disc mechanics, reveal equilibrium and time-dependent behaviors that are qualitatively similar to native tissue, although lesser in magnitude. Further, we demonstrate that cells seeded into both AF and NP regions adopt distinct morphologies that mirror those seen in native tissue, and that, in the AF region, this ordered community of cells deposit matrix that is organized in an angle-ply configuration. Finally, constructs demonstrate functional development with long-term in vitro culture. These findings provide a new approach for disc tissue engineering that replicates multi-scale form and function of the intervertebral disc, providing a foundation from which to build a multi-scale, biologic, anatomically and hierarchically relevant composite disc analogue for eventual disc replacement.

Intensities and spectral features of the {}^{4}{\\rm{I}}_{13/2}-{}^{4}{\\rm{I}}_{15/2} potential laser transition of Er3+ centers in CaF2-CeF3 disordered crystal

NASA Astrophysics Data System (ADS)

Wang, Qing-Guo; Su, Liangbi; Liu, Jun-Fang; Liu, Bin; Wu, Feng; Luo, Ping; Zhao, Heng-Yu; Shi, Jiao-Jiao; Xue, Yan-Yan; Xu, Xiao-Dong; Ryba-Romanowski, Witold; Solarz, Piotr; Lisiecki, Radoslaw; Wang, Zhan-Shan; Tang, Hui-Li; Xu, Jun

2017-10-01

Not Available Project supported by Shanghai Engineering Research Center for Sapphire Crystals, China (Grant No. 14DZ2252500), the Fund of Key Laboratory of Optoelectronic Materials Chemistry and Physics Chinese Academy of Sciences (Grant No. 2008DP17301), the Fundamental Research Funds for the Central Universities of China, the National Natural Science Foundation of China and China Academy of Engineering Physics Joint Fund (Grant No. U1530152), the National Natural Science Foundation of China (Grant Nos. 61475177 and 61621001), the Natural Science Foundation of Shanghai Municiple, China (Grant No. 13ZR1446100), and the MOE Key Laboratory of Advanced Micro-Structured Materials of China.

A plea for judgment.

PubMed

Davis, Michael

2012-12-01

Judgment is central to engineering, medicine, the sciences and many other practical activities. For example, one who otherwise knows what engineers know but lacks "engineering judgment" may be an expert of sorts, a handy resource much like a reference book or database, but cannot be a competent engineer. Though often overlooked or at least passed over in silence, the central place of judgment in engineering, the sciences, and the like should be obvious once pointed out. It is important here because it helps to explain where ethics fits into these disciplines. There is no good engineering, no good science, and so on without good judgment and no good judgment in these disciplines without ethics. Doing even a minimally decent job of teaching one of these disciplines necessarily includes teaching its ethics; teaching the ethics is teaching the discipline (or at least a large part of it).

Interdisciplinary Interactions During R&D and Early Design of Large Engineered Systems

NASA Technical Reports Server (NTRS)

McGowan, Anna-Maria Rivas

2014-01-01

Designing Large-Scale Complex Engineered Systems (LaCES) such as aircraft and submarines requires the input of thousands of engineers and scientists whose work is proximate in neither time nor space. Comprehensive knowledge of the system is dispersed among specialists whose expertise is in typically one system component or discipline. This study examined the interactive work practices among such specialists seeking to improve engineering practice through a rigorous and theoretical understanding of current practice. This research explored current interdisciplinary practices and perspectives during R&D and early LaCES design and identified why these practices and perspectives prevail and persist. The research design consisted of a three-fold, integrative approach that combined an open-ended survey, semi-structured interviews, and ethnography. Significant empirical data from experienced engineers and scientists in a large engineering organization were obtained and integrated with theories from organization science and engineering. Qualitative analysis was used to obtain a holistic, contextualized understanding. The over-arching finding is that issues related to cognition, organization, and social interrelations mostly dominate interactions across disciplines. Engineering issues, such as the integration of hardware or physics-based models, are not as significant. For example, organization culture is an important underlying factor that guided researchers more toward individual sovereignty over cross-disciplinarity. The organization structure and the engineered system architecture also serve as constraints to the engineering work. Many differences in work practices were observed, including frequency and depth of interactions, definition or co-construction of requirements, clarity or creation of the system architecture, work group proximity, and cognitive challenges. Practitioners are often unaware of these differences resulting in confusion and incorrect assumptions regarding work expectations. Cognitively, the enactment and coconstruction of knowledge are the fundamental tasks of the interdisciplinary interactions. Distributed and collective cognition represent most of the efforts. Argument, ignorance, learning, and creativity are interrelated aspects of the interactions that cause discomfort but yield benefits such as problem mitigation, broader understanding, and improved system design and performance. The quality and quantity of social interrelations are central to all work across disciplines with reciprocity, respectful engagement, and heedful interrelations being significant to the effectiveness of the engineering and scientific work.

An Engineering Research Program for High School Science Teachers: Year Two Changes and Results

ERIC Educational Resources Information Center

DeJong, Brian P.; Yelamarthi, Kumar; Kaya, Tolga

2016-01-01

The research experiences for teachers program at Central Michigan University was initiated to team in-service and pre-service teachers with undergraduate engineering students and engineering faculty, in an engineering research setting. During the six-week program, teachers learn engineering concepts and develop high-school instructional material…

On the internal structure of relativistic jets collimated by ambient gas pressure

NASA Astrophysics Data System (ADS)

Beskin, V. S.; Chernoglazov, A. V.; Kiselev, A. M.; Nokhrina, E. E.

2017-12-01

Recent progress in very long baseline interferometry (VLBI) observations of relativistic jets outflowing from active galactic nuclei gives us direct information about jet width rjet(l) dependence on the distance l from the 'central engine'. Being the missing link in previous works, this relation opens the possibility of determining the internal structure of a jet. In this article, we consider a relativistic jet submerged in an external medium with finite gas pressure Pext. Neither an external magnetic field nor an infinitely thin current sheet will be assumed. This approach allows us to construct a reasonable solution in which both the magnetic field and the flow velocity vanish at the jet boundary r = rjet. In particular, the connection between external gas pressure and internal structure of a relativistic jet is determined.

The Road to Total Earthquake Safety

NASA Astrophysics Data System (ADS)

Frohlich, Cliff

Cinna Lomnitz is possibly the most distinguished earthquake seismologist in all of Central and South America. Among many other credentials, Lomnitz has personally experienced the shaking and devastation that accompanied no fewer than five major earthquakes—Chile, 1939; Kern County, California, 1952; Chile, 1960; Caracas,Venezuela, 1967; and Mexico City, 1985. Thus he clearly has much to teach someone like myself, who has never even actually felt a real earthquake.What is this slim book? The Road to Total Earthquake Safety summarizes Lomnitz's May 1999 presentation at the Seventh Mallet-Milne Lecture, sponsored by the Society for Earthquake and Civil Engineering Dynamics. His arguments are motivated by the damage that occurred in three earthquakes—Mexico City, 1985; Loma Prieta, California, 1989; and Kobe, Japan, 1995. All three quakes occurred in regions where earthquakes are common. Yet in all three some of the worst damage occurred in structures located a significant distance from the epicenter and engineered specifically to resist earthquakes. Some of the damage also indicated that the structures failed because they had experienced considerable rotational or twisting motion. Clearly, Lomnitz argues, there must be fundamental flaws in the usually accepted models explaining how earthquakes generate strong motions, and how we should design resistant structures.

Engine Air Intake Manifold Having Built In Intercooler

DOEpatents

Freese, V, Charles E.

2000-09-12

A turbocharged V type engine can be equipped with an exhaust gas recirculation cooler integrated into the intake manifold, so as to achieve efficiency, cost reductions and space economization improvements. The cooler can take the form of a tube-shell heat exchanger that utilizes a cylindrical chamber in the air intake manifold as the heat exchanger housing. The intake manifold depends into the central space formed by the two banks of cylinders on the V type engine, such that the central space is effectively utilized for containing the manifold and cooler.

ELECTRICAL LINES ARRIVE FROM CENTRAL FACILITIES AREA, SOUTH OF MTR. ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

ELECTRICAL LINES ARRIVE FROM CENTRAL FACILITIES AREA, SOUTH OF MTR. EXCAVATION RUBBLE IN FOREGROUND. CONTRACTOR CRAFT SHOPS, CRANES, AND OTHER MATERIALS ON SITE. CAMERA FACES EAST, WITH LITTLE BUTTE AND MIDDLE BUTTE IN DISTANCE. INL NEGATIVE NO. 335. Unknown Photographer, 7/1/1950 - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

A relativistic type Ibc supernova without a detected gamma-ray burst.

PubMed

Soderberg, A M; Chakraborti, S; Pignata, G; Chevalier, R A; Chandra, P; Ray, A; Wieringa, M H; Copete, A; Chaplin, V; Connaughton, V; Barthelmy, S D; Bietenholz, M F; Chugai, N; Stritzinger, M D; Hamuy, M; Fransson, C; Fox, O; Levesque, E M; Grindlay, J E; Challis, P; Foley, R J; Kirshner, R P; Milne, P A; Torres, M A P

2010-01-28

Long duration gamma-ray bursts (GRBs) mark the explosive death of some massive stars and are a rare sub-class of type Ibc supernovae. They are distinguished by the production of an energetic and collimated relativistic outflow powered by a central engine (an accreting black hole or neutron star). Observationally, this outflow is manifested in the pulse of gamma-rays and a long-lived radio afterglow. Until now, central-engine-driven supernovae have been discovered exclusively through their gamma-ray emission, yet it is expected that a larger population goes undetected because of limited satellite sensitivity or beaming of the collimated emission away from our line of sight. In this framework, the recovery of undetected GRBs may be possible through radio searches for type Ibc supernovae with relativistic outflows. Here we report the discovery of luminous radio emission from the seemingly ordinary type Ibc SN 2009bb, which requires a substantial relativistic outflow powered by a central engine. A comparison with our radio survey of type Ibc supernovae reveals that the fraction harbouring central engines is low, about one per cent, measured independently from, but consistent with, the inferred rate of nearby GRBs. Independently, a second mildly relativistic supernova has been reported.

Search for a Signature of Interaction between Relativistic Jet and Progenitor in Gamma-Ray Bursts

NASA Astrophysics Data System (ADS)

Yoshida, Kazuki; Yoneoku, Daisuke; Sawano, Tatsuya; Ito, Hirotaka; Matsumoto, Jin; Nagataki, Shigehiro

2017-11-01

The time variability of prompt emission in gamma-ray bursts (GRBs) is expected to originate from the temporal behavior of the central engine activity and the jet propagation in the massive stellar envelope. Using a pulse search algorithm for bright GRBs, we investigate the time variability of gamma-ray light curves to search a signature of the interaction between the jet and the inner structure of the progenitor. Since this signature might appear in the earlier phase of prompt emission, we divide the light curves into the initial phase and the late phase by referring to the trigger time and the burst duration of each GRB. We also adopt this algorithm for GRBs associated with supernovae/hypernovae that certainly are accompanied by massive stars. However, there is no difference between each pulse interval distribution described by a lognorma distribution in the two phases. We confirm that this result can be explained by the photospheric emission model if the energy injection of the central engine is not steady or completely periodic but episodic and described by the lognormal distribution with a mean of ˜1 s.

Search for a Signature of Interaction between Relativistic Jet and Progenitor in Gamma-Ray Bursts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yoshida, Kazuki; Yoneoku, Daisuke; Sawano, Tatsuya

The time variability of prompt emission in gamma-ray bursts (GRBs) is expected to originate from the temporal behavior of the central engine activity and the jet propagation in the massive stellar envelope. Using a pulse search algorithm for bright GRBs, we investigate the time variability of gamma-ray light curves to search a signature of the interaction between the jet and the inner structure of the progenitor. Since this signature might appear in the earlier phase of prompt emission, we divide the light curves into the initial phase and the late phase by referring to the trigger time and the burstmore » duration of each GRB. We also adopt this algorithm for GRBs associated with supernovae/hypernovae that certainly are accompanied by massive stars. However, there is no difference between each pulse interval distribution described by a lognorma distribution in the two phases. We confirm that this result can be explained by the photospheric emission model if the energy injection of the central engine is not steady or completely periodic but episodic and described by the lognormal distribution with a mean of ∼1 s.« less

Controlling octahedral rotations in a perovskite via strain doping

DOE PAGES

Herklotz, Andreas; Biegalski, Michael D.; Lee, Ho Nyung; ...

2016-05-24

The perovskite unit cell is the fundamental building block of many functional materials. The manipulation of this crystal structure is known to be of central importance to controlling many technologically promising phenomena related to superconductivity, multiferroicity, mangetoresistivity, and photovoltaics. The broad range of properties that this structure can exhibit is in part due to the centrally coordinated octahedra bond flexibility, which allows for a multitude of distortions from the ideal highly symmetric structure. However, continuous and fine manipulation of these distortions has never been possible. Here, we show that controlled insertion of He atoms into an epitaxial perovskite film canmore » be used to finely tune the lattice symmetry by modifying the local distortions, i.e., octahedral bonding angle and length. Orthorhombic SrRuO 3 films coherently grown on SrTiO 3 substrates are used as a model system. Implanted He atoms are confirmed to induce out-of-plane strain, which provides the ability to controllably shift the bulk-like orthorhombically distorted phase to a tetragonal structure by shifting the oxygen octahedra rotation pattern. Lastly, these results demonstrate that He implantation offers an entirely new pathway to strain engineering of perovskite-based complex oxide thin films, useful for creating new functionalities or properties in perovskite materials.« less

She's an Engineer

NASA Image and Video Library

2016-11-05

Junior Girl Scouts from two locals conceils, Girl Scouts of Central Maryland and Girl Scouts of Nations Capital, participated in She's an Engineer! Girl Scout program on November 3, 2016. They met with female NASA engineers and tested rover models in simulated I&T stations to explore the Engineering Design process.

Gravitational spreading of steep-sided ridges ("sackung") in Western United States

USGS Publications Warehouse

Radbruch-Hall, D. H.; Varnes, D.J.; Savage, W.Z.

1976-01-01

Large-scale gravitational spreading and movement along fractures of steep-sided ridges in the mountainous areas of the western United States are characterized by linear fissures, trenches, and uphill-facing scarps on tops and sides of ridges. Spreading appears to take place by movement along disconnected planes and/or by slow plastic deformation of a rock mass. In some places, valleyward squeezing out of weak shales overlain by rigid rocks causes extensional fracturing and outward movement of the rigid layers, as illustrated by extension of two laccoliths overlying Mancos Shale, one at Dolores Peak and another at Crested Butte in western Colorado. Gravitational forces acting on a ridge of more homogeneous material causes tensional spreading of the ridge parallel to its long axis, for example in fractured granitic rock north of Mt. Massive in central Colorado, where a survey course has been established to monitor the movement. Recognition and understanding of these large-scale gravitational features and the mechanism that causes them are pertinent to site selection and design of engineering structures in high mountains. If fractures extend to considerable depth and if movement is continuing, engineering structures in valleys or tunnels through the spreading ridges could be damaged. ?? 1976 International Association of Engineering Geology.

Civil Engineering in Primary Schools

ERIC Educational Resources Information Center

Brown, Martin; Strong, Alan

2010-01-01

For many children of primary school age, an engineer is the man who comes to service the central heating system or who fixes the family car when it breaks down. Most have never met a "real" professional engineer, and have no idea of what is involved in the exciting world of engineering. Most assume that engineers are men. To try to…

Integrated flight/propulsion control system design based on a centralized approach

NASA Technical Reports Server (NTRS)

Garg, Sanjay; Mattern, Duane L.; Bullard, Randy E.

1989-01-01

An integrated flight/propulsion control system design is presented for the piloted longitudinal landing task with a modern, statically unstable, fighter aircraft. A centralized compensator based on the Linear Quadratic Gaussian/Loop Transfer Recovery methodology is first obtained to satisfy the feedback loop performance and robustness specificiations. This high-order centralized compensator is then partitioned into airframe and engine sub-controllers based on modal controllability/observability for the compensator modes. The order of the sub-controllers is then reduced using internally-balanced realization techniques and the sub-controllers are simplified by neglecting the insignificant feedbacks. These sub-controllers have the advantage that they can be implemented as separate controllers on the airframe and the engine while still retaining the important performance and stability characteristics of the full-order centralized compensator. Command prefilters are then designed for the closed-loop system with the simplified sub-controllers to obtain the desired system response to airframe and engine command inputs, and the overall system performance evaluation results are presented.

Re-Engineering Vocational and Technical Education (VTE) for Sustainable Development in North Central Geo-Political Zone, Nigeria

ERIC Educational Resources Information Center

Sofoluwe, Abayomi Olumade

2013-01-01

The purpose of the study is to re-engineer vocational and technical education for sustainable development in the North Central Geo-Political Zone in Nigeria. The research design adopted was a survey inferential type. Stratified random was used to select 36 schools out of 98 schools while 920 students out of 3680 students were sampled. The data…

Effects of Shocks on Emission from Central Engines of Active Galactic Nuclei. I

NASA Technical Reports Server (NTRS)

Sivron, R.; Caditz, D.; Tsuruta, S.

1996-01-01

In this paper we show that perturbations of the accretion flow within the central engines of some active galactic nuclei (AGNS) are likely to form shock waves in the accreting plasma. Such shocks, which may be either collisional or collisionless, can contribute to the observed high-energy temporal and spectral variability. Our rationale is the following: Observations show that the continuum emission probably originates in an optically thin, hot plasma in the AGN central engine. The flux and spectrum from this hot plasma varies significantly over light crossing timescales. Several authors have suggested that macroscopic perturbations contained within this plasma are the sources of this variability. In order to produce the observed emission the perturbations must be radiatively coupled with the optically thin hot matter and must also move with high velocities. We suggest that shocks, which can be very effective in randomizing the bulk motion of the perturbations, are responsible for this coupling. Shocks should form in the central engine, because the temperatures and magnetic fields are probably reduced below their virial values by radiative dissipation. Perturbations moving at Keplerian speeds, or strong non-linear excitations, result in supersonic and super-Alfvenic velocities leading to shock waves within the hot plasma. We show that even a perturbation smaller than the emitting region can form a shock that significantly modifies the continuum emission in an AGN, and that the spectral and temporal variability from such a shock generally resembles those of radio-quiet AGNS. As an example, the shock inducing perturbation in our model is a small main-sequence star, the capturing and eventual accretion of which are known to be a plausible process. We argue that shocks in the central engine may also provide a natural triggering mechanism for the "cold" component of Guilbert & Rees two-phase medium and an efficient mecha- nism for angular momentum transfer. Current and future missions, such as ASCA, XTE, XMM, AXAF, and ASTRO-E may determine the importance of shock-related emission from the central engines of AGNS.

High-Temperature Smart Structures for Engine Noise Reduction and Performance Enhancement

NASA Technical Reports Server (NTRS)

Quackenbush, Todd R.; McKillip, Robert M., Jr.

2011-01-01

One of key NASA goals is to develop and integrate noise reduction technology to enable unrestricted air transportation service to all communities. One of the technical priorities of this activity has been to account for and reduce noise via propulsion/airframe interactions, identifying advanced concepts to be integrated with the airframe to mitigate these noise-producing mechanisms. An adaptive geometry chevron using embedded smart structures technology offers the possibility of maximizing engine performance while retaining and possibly enhancing the favorable noise characteristics of current designs. New high-temperature shape memory alloy (HTSMA) materials technology enables the devices to operate in both low-temperature (fan) and high-temperature (core) exhaust flows. Chevron-equipped engines have demonstrated reduced noise in testing and operational use. It is desirable to have the noise benefits of chevrons in takeoff/landing conditions, but have them deployed into a minimum drag position for cruise flight. The central feature of the innovation was building on rapidly maturing HTSMA technology to implement a next-generation aircraft noise mitigation system centered on adaptive chevron flow control surfaces. In general, SMA-actuated devices have the potential to enhance the demonstrated noise reduction effectiveness of chevron systems while eliminating the associated performance penalty. The use of structurally integrated smart devices will minimize the mechanical and subsystem complexity of this implementation. The central innovations of the effort entail the modification of prior chevron designs to include a small cut that relaxes structural stiffness without compromising the desired flow characteristics over the surface; the reorientation of SMA actuation devices to apply forces to deflect the chevron tip, exploiting this relaxed stiffness; and the use of high-temperature SMA (HTSMA) materials to enable operation in the demanding core chevron environment. The overall conclusion of these design studies was that the cut chevron concept is a critical enabling step in bringing the variable geometry core chevron within reach. The presence of the cut may be aerodynamically undesirable in some respects, but it is present only when the chevron is not immersed in the core jet exhaust. When deployed, the gap closes as the chevron tip enters the high-speed, high-temperature core stream. Aeroacoustic testing and flow visualization support the contention that this cut is inconsequential to chevron performance.

San Francisco floating STOLport study

NASA Technical Reports Server (NTRS)

1974-01-01

The operational, economic, environmental, social and engineering feasibility of utilizing deactivated maritime vessels as a waterfront quiet short takeoff and landing facility to be located near the central business district of San Francisco was investigated. Criteria were developed to evaluate each site, and minimum standards were established for each criterion. Predicted conditions at the two sites were compared to the requirements for each of the 11 criteria as a means of evaluating site performance. Criteria include land use, community structure, economic impact, access, visual character, noise, air pollution, natural environment, weather, air traffic, and terminal design.

Research and development of a digital design system for hull structures

NASA Astrophysics Data System (ADS)

Zhan, Yi-Ting; Ji, Zhuo-Shang; Liu, Yin-Dong

2007-06-01

Methods used for digital ship design were studied and formed the basis of a proposed frame model suitable for ship construction modeling. Based on 3-D modeling software, a digital design system for hull structures was developed. Basic software systems for modeling, modifying, and assembly simulation were developed. The system has good compatibility, and models created by it can be saved in different 3-D file formats, and 2D engineering drawings can be output directly. The model can be modified dynamically, overcoming the necessity of repeated modifications during hull structural design. Through operations such as model construction, intervention inspection, and collision detection, problems can be identified and modified during the hull structural design stage. Technologies for centralized control of the system, database management, and 3-D digital design are integrated into this digital model in the preliminary design stage of shipbuilding.

Enhanced nutrient transport improves the depth-dependent properties of tri-layered engineered cartilage constructs with zonal co-culture of chondrocytes and MSCs.

PubMed

Kim, Minwook; Farrell, Megan J; Steinberg, David R; Burdick, Jason A; Mauck, Robert L

2017-08-01

Biomimetic design in cartilage tissue engineering is a challenge given the complexity of the native tissue. While numerous studies have generated constructs with near-native bulk properties, recapitulating the depth-dependent features of native tissue remains a challenge. Furthermore, limitations in nutrient transport and matrix accumulation in engineered constructs hinders maturation within the central core of large constructs. To overcome these limitations, we fabricated tri-layered constructs that recapitulate the depth-dependent cellular organization and functional properties of native tissue using zonally derived chondrocytes co-cultured with MSCs. We also introduced porous hollow fibers (HFs) and HFs/cotton threads to enhance nutrient transport. Our results showed that tri-layered constructs with depth-dependent organization and properties could be fabricated. The addition of HFs or HFs/threads improved matrix accumulation in the central core region. With HF/threads, the local modulus in the deep region of tri-layered constructs nearly matched that of native tissue, though the properties in the central regions remained lower. These constructs reproduced the zonal organization and depth-dependent properties of native tissue, and demonstrate that a layer-by-layer fabrication scheme holds promise for the biomimetic repair of focal cartilage defects. Articular cartilage is a highly organized tissue driven by zonal heterogeneity of cells, extracellular matrix proteins and fibril orientations, resulting in depth-dependent mechanical properties. Therefore, the recapitulation of the functional properties of native cartilage in a tissue engineered construct requires such a biomimetic design of the morphological organization, and this has remained a challenge in cartilage tissue engineering. This study demonstrates that a layer-by-layer fabrication scheme, including co-cultures of zone-specific articular CHs and MSCs, can reproduce the depth-dependent characteristics and mechanical properties of native cartilage while minimizing the need for large numbers of chondrocytes. In addition, introduction of a porous hollow fiber (combined with a cotton thread) enhanced nutrient transport and depth-dependent properties of the tri-layered construct. Such a tri-layered construct may provide critical advantages for focal cartilage repair. These constructs hold promise for restoring native tissue structure and function, and may be beneficial in terms of zone-to-zone integration with adjacent host tissue and providing more appropriate strain transfer after implantation. Copyright © 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

PHOTOSPHERE EMISSION FROM A HYBRID RELATIVISTIC OUTFLOW WITH ARBITRARY DIMENSIONLESS ENTROPY AND MAGNETIZATION IN GRBs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gao, He; Zhang, Bing, E-mail: gaohe@physics.unlv.edu, E-mail: zhang@physics.unlv.edu, E-mail: hug18@psu.edu

2015-03-10

In view of the recent Fermi observations of gamma-ray burst (GRB) prompt emission spectra, we develop a theory of photosphere emission of a hybrid relativistic outflow with a hot fireball component (defined by dimensionless entropy η) and a cold Poynting-flux component (defined by magnetization σ{sub 0} at the central engine). We consider the scenarios both without and with sub-photospheric magnetic dissipations. Based on a simplified toy model of jet dynamics, we develop two approaches: a 'bottom-up' approach to predict the temperature (for a non-dissipative photosphere) and luminosity of the photosphere emission and its relative brightness for a given pair ofmore » (η, σ{sub 0}); and a 'top-down' approach to diagnose central engine parameters (η and σ{sub 0}) based on the observed quasi-thermal photosphere emission properties. We show that a variety of observed GRB prompt emission spectra with different degrees of photosphere thermal emission can be reproduced by varying η and σ{sub 0} within the non-dissipative photosphere scenario. In order to reproduce the observed spectra, the outflows of most GRBs need to have a significant σ, both at the central engine and at the photosphere. The σ value at 10{sup 15} cm from the central engine (a possible non-thermal emission site) is usually also greater than unity, so that internal-collision-induced magnetic reconnection and turbulence (ICMART) may be the mechanism to power the non-thermal emission. We apply our top-down approach to GRB 110721A and find that the temporal evolution behavior of its blackbody component can be well interpreted with a time-varying (η, σ{sub 0}) at the central engine, instead of invoking a varying engine base size r {sub 0} as proposed by previous authors.« less

Constraining the Type of Central Engine of GRBs with Swift Data

NASA Astrophysics Data System (ADS)

Li, Liang; Wu, Xue-Feng; Lei, Wei-Hua; Dai, Zi-Gao; Lian, En-Wei; Ryde, Felix

2018-06-01

The central engine of gamma-ray bursts (GRBs) is poorly constrained. There exist two main candidates: a fast-rotating black hole and a rapidly spinning magnetar. Furthermore, X-ray plateaus are widely accepted to be the energy injection into the external shock. In this paper, we systematically analyze the Swift/XRT light curves of 101 GRBs having plateau phases and known redshifts (before 2017 May). Since a maximum energy budget (∼2 × 1052 erg) exists for magnetars but not for black holes, this provides a good clue to identifying the type of GRB central engine. We calculate the isotropic kinetic energy E K,iso and the isotropic X-ray energy release E X,iso for individual GRBs. We identify three categories based on how likely a black hole harbors a central engine: “Gold” (9 out of 101; both E X,iso and E K,iso exceed the energy budget), “Silver” (69 out of 101; E X,iso less than the limit but E K,iso greater than the limit), and “Bronze” (23 out of 101; the energies are not above the limit). We then derive and test the black hole parameters with the Blandford–Znajek mechanism, and find that the observations of the black hole candidate (“Gold” + “Silver”) samples are consistent with the expectations of the black hole model. Furthermore, we also test the magnetar candidate (“Bronze”) sample with the magnetar model, and find that the magnetar surface magnetic field (B p ) and initial spin period (P 0) fall into reasonable ranges. Our analysis indicates that if the magnetar wind is isotropic, a magnetar central engine is possible for 20% of the analyzed GRBs. For most GRBs, a black hole is most likely operating.

In vivo laser confocal microscopic analysis of corneal K-structures after keratorefractive surgery (LASIK and epi-LASIK).

PubMed

Yokogawa, Hideaki; Kobayashi, Akira; Tagawa, Kosaku; Sugiyama, Kazuhisa

2010-01-01

To demonstrate alterations of corneal K-structures (sub-Bowman's fibrous structures) after keratorefractive surgery by in vivo laser confocal microscopy and to look for association of K-structures with fluorescein-stained anterior corneal mosaic (ACM). Five patients (nine eyes) participated in this study. For four patients, one eye was evaluated after laser in situ keratomileusis (LASIK) and the other after epipolis-laser in situ keratomileusis (epi-LASIK). For one patient, the left eye was evaluated after epithelial debridement. A photograph of the ACM was obtained. Central corneal regions were scanned by Heidelberg Retina Tomograph 2 Rostock Cornea Module (Heidelberg Engineering GmbH, Heidelberg, Germany). The ACM and K-structures disappeared in all corneas after epi-LASIK, but not after LASIK and epithelial debridement cornea. The presence of K-structures and ACM may be an index to identify eyes that had a previous refractive surgical procedure (surface ablation or LASIK) and be a health index of Bowman layer and adjacent anterior stroma. Copyright 2010, SLACK Incorporated.

Engine structures modeling software system: Computer code. User's manual

NASA Technical Reports Server (NTRS)

1992-01-01

ESMOSS is a specialized software system for the construction of geometric descriptive and discrete analytical models of engine parts, components and substructures which can be transferred to finite element analysis programs such as NASTRAN. The software architecture of ESMOSS is designed in modular form with a central executive module through which the user controls and directs the development of the analytical model. Modules consist of a geometric shape generator, a library of discretization procedures, interfacing modules to join both geometric and discrete models, a deck generator to produce input for NASTRAN and a 'recipe' processor which generates geometric models from parametric definitions. ESMOSS can be executed both in interactive and batch modes. Interactive mode is considered to be the default mode and that mode will be assumed in the discussion in this document unless stated otherwise.

77 FR 33560 - Woodland Rail, LLC-Acquisition and Operation Exemption-Line of Maine Central Railroad Co.

Federal Register 2010, 2011, 2012, 2013, 2014

2012-06-06

... United States. The end points of the Line are at engineering station 64+17 in Baileyville and engineering... Woodland Junction, Me., which is engineering station 363+45, and engineering station 393+37, and another spur track at St. Croix Junction, Me., which is engineering station 6817+12.\\1\\ \\1\\ In a related...

A monomeric TIM-barrel structure from Pyrococcus furiosus is optimized for extreme temperatures.

PubMed

Repo, Heidi; Oeemig, Jesper S; Djupsjöbacka, Janica; Iwaï, Hideo; Heikinheimo, Pirkko

2012-11-01

The structure of phosphoribosyl anthranilate isomerase (TrpF) from the hyperthermophilic archaeon Pyrococcus furiosus (PfTrpF) has been determined at 1.75 Å resolution. The PfTrpF structure has a monomeric TIM-barrel fold which differs from the dimeric structures of two other known thermophilic TrpF proteins. A comparison of the PfTrpF structure with the two known bacterial thermophilic TrpF structures and the structure of a related mesophilic protein from Escherichia coli (EcTrpF) is presented. The thermophilic TrpF structures contain a higher proportion of ion pairs and charged residues compared with the mesophilic EcTrpF. These residues contribute to the closure of the central barrel and the stabilization of the barrel and the surrounding α-helices. In the monomeric PfTrpF conserved structural water molecules are mostly absent; instead, the structural waters are replaced by direct side-chain-main-chain interactions. As a consequence of these combined mechanisms, the P. furiosus enzyme is a thermodynamically stable and entropically optimized monomeric TIM-barrel enzyme which defines a good framework for further protein engineering for industrial applications.

[Micro/nano-engineering to control growth of neuronal cells and tissue engineering applied to the central nervous system].

PubMed

Béduer, Amélie; Vaysse, Laurence; Loubinoux, Isabelle; Vieu, Christophe

2013-01-01

Central nervous system pathologies are often characterized by the loss of cell populations. A promising therapy now being developed consists in using bioactive materials, associating grafted cells to biopolymers which provide a scaffold for the in vitro building of new tissues, to be implanted in vivo. In the present article, the state of the art of this field, at crossroads between microtechnology and neuroscience, is described in detail; thereafter our own approach and results about interactions between adult human neural stem cells and microstructured polymers are summarized and discussed. In a second part, some central nervous system repair strategies, based on cerebral tissue engineering, are presented. We will report the main results of our studies to work out and characterize in vivo a cerebral bioprosthesis. © Société de Biologie, 2014.

How gravitational-wave observations can shape the gamma-ray burst paradigm

NASA Astrophysics Data System (ADS)

Bartos, I.; Brady, P.; Márka, S.

2013-06-01

By reaching through shrouding blastwaves, efficiently discovering off-axis events and probing the central engine at work, gravitational wave (GW) observations will soon revolutionize the study of gamma-ray bursts. Already, analyses of GW data targeting gamma-ray bursts have helped constrain the central engines of selected events. Advanced GW detectors with significantly improved sensitivities are under construction. After outlining the GW emission mechanisms from gamma-ray burst progenitors (binary coalescences, stellar core collapses, magnetars and others) that may be detectable with advanced detectors, we review how GWs will improve our understanding of gamma-ray burst central engines, their astrophysical formation channels and the prospects and methods for different search strategies. We place special emphasis on multimessenger searches. To achieve the most scientific benefit, GW, electromagnetic and neutrino observations should be combined to provide greater discriminating power and science reach.

Framework for Multidisciplinary Analysis, Design, and Optimization with High-Fidelity Analysis Tools

NASA Technical Reports Server (NTRS)

Orr, Stanley A.; Narducci, Robert P.

2009-01-01

A plan is presented for the development of a high fidelity multidisciplinary optimization process for rotorcraft. The plan formulates individual disciplinary design problems, identifies practical high-fidelity tools and processes that can be incorporated in an automated optimization environment, and establishes statements of the multidisciplinary design problem including objectives, constraints, design variables, and cross-disciplinary dependencies. Five key disciplinary areas are selected in the development plan. These are rotor aerodynamics, rotor structures and dynamics, fuselage aerodynamics, fuselage structures, and propulsion / drive system. Flying qualities and noise are included as ancillary areas. Consistency across engineering disciplines is maintained with a central geometry engine that supports all multidisciplinary analysis. The multidisciplinary optimization process targets the preliminary design cycle where gross elements of the helicopter have been defined. These might include number of rotors and rotor configuration (tandem, coaxial, etc.). It is at this stage that sufficient configuration information is defined to perform high-fidelity analysis. At the same time there is enough design freedom to influence a design. The rotorcraft multidisciplinary optimization tool is built and substantiated throughout its development cycle in a staged approach by incorporating disciplines sequentially.

3D in vitro modeling of the central nervous system

PubMed Central

Hopkins, Amy M.; DeSimone, Elise; Chwalek, Karolina; Kaplan, David L.

2015-01-01

There are currently more than 600 diseases characterized as affecting the central nervous system (CNS) which inflict neural damage. Unfortunately, few of these conditions have effective treatments available. Although significant efforts have been put into developing new therapeutics, drugs which were promising in the developmental phase have high attrition rates in late stage clinical trials. These failures could be circumvented if current 2D in vitro and in vivo models were improved. 3D, tissue-engineered in vitro systems can address this need and enhance clinical translation through two approaches: (1) bottom-up, and (2) top-down (developmental/regenerative) strategies to reproduce the structure and function of human tissues. Critical challenges remain including biomaterials capable of matching the mechanical properties and extracellular matrix (ECM) composition of neural tissues, compartmentalized scaffolds that support heterogeneous tissue architectures reflective of brain organization and structure, and robust functional assays for in vitro tissue validation. The unique design parameters defined by the complex physiology of the CNS for construction and validation of 3D in vitro neural systems are reviewed here. PMID:25461688

The Signature of the Central Engine in the Weakest Relativistic Explosions: GRB 100316D

NASA Astrophysics Data System (ADS)

Margutti, R.; Soderberg, A. M.; Wieringa, M. H.; Edwards, P. G.; Chevalier, R. A.; Morsony, B. J.; Barniol Duran, R.; Sironi, L.; Zauderer, B. A.; Milisavljevic, D.; Kamble, A.; Pian, E.

2013-11-01

We present late-time radio and X-ray observations of the nearby sub-energetic gamma-ray burst (GRB)100316D associated with supernova (SN) 2010bh. Our broad-band analysis constrains the explosion properties of GRB 100316D to be intermediate between highly relativistic, collimated GRBs and the spherical, ordinary hydrogen-stripped SNe. We find that ~1049 erg is coupled to mildly relativistic (Γ = 1.5-2), quasi-spherical ejecta, expanding into a medium previously shaped by the progenitor mass-loss with a rate of \\dot{M}\\, {\\sim }\\, 10^{-5}\\,M_{\\odot }\\,yr^{-1} (for an assumed wind density profile and wind velocity vw = 1000 km s-1). The kinetic energy profile of the ejecta argues for the presence of a central engine and identifies GRB 100316D as one of the weakest central-engine-driven explosions detected to date. Emission from the central engine is responsible for an excess of soft X-ray radiation that dominates over the standard afterglow at late times (t > 10 days). We connect this phenomenology with the birth of the most rapidly rotating magnetars. Alternatively, accretion onto a newly formed black hole might explain the excess of radiation. However, significant departure from the standard fall-back scenario is required.

Radio afterglow rebrightening: evidence for multiple active phases in gamma-ray burst central engines

NASA Astrophysics Data System (ADS)

Li, Long-Biao; Zhang, Zhi-Bin; Rice, Jared

2015-09-01

The rebrightening phenomenon is an interesting feature in some X-ray, optical, and radio afterglows of gamma-ray bursts (GRBs). Here, we propose a possible energy-supply assumption to explain the rebrightenings of radio afterglows, in which the central engine with multiple active phases can supply at least two GRB pulses in a typical GRB duration time. Considering the case of double pulses supplied by the central engine, the double pulses have separate physical parameters, except for the number density of the surrounding interstellar medium (ISM). Their independent radio afterglows are integrated by the ground detectors to form the rebrightening phenomenon. In this Letter, we firstly simulate diverse rebrightening light curves under consideration of different and independent physical parameters. Using this assumption, we also give our best fit to the radio afterglow of GRB 970508 at three frequencies of 1.43, 4.86, and 8.46 GHz. We suggest that the central engine may be active continuously at a timescale longer than that of a typical GRB duration time as many authors have suggested (e.g., Zhang et al., Astrophys. J. 787:66, 2014; Gao and Mészáros, Astrophys. J. 802:90, 2015), and that it may supply enough energy to cause the long-lasting rebrightenings observed in some GRB afterglows.

Magnetar-powered Supernovae in Two Dimensions. II. Broad-line Supernovae Ic

NASA Astrophysics Data System (ADS)

Chen, Ke-Jung; Moriya, Takashi J.; Woosley, Stan; Sukhbold, Tuguldur; Whalen, Daniel J.; Suwa, Yudai; Bromm, Volker

2017-04-01

Nascent neutron stars (NSs) with millisecond periods and magnetic fields in excess of 1016 Gauss can drive highly energetic and asymmetric explosions known as magnetar-powered supernovae. These exotic explosions are one theoretical interpretation for supernovae Ic-BL, which are sometimes associated with long gamma-ray bursts. Twisted magnetic field lines extract the rotational energy of the NS and release it as a disk wind or a jet with energies greater than 1052 erg over ˜20 s. What fraction of the energy of the central engine go into the wind and the jet remain unclear. We have performed two-dimensional hydrodynamical simulations of magnetar-powered supernovae (SNe) driven by disk winds and jets with the CASTRO code to investigate the effect of the central engine on nucleosynthetic yields, mixing, and light curves. We find that these explosions synthesize less than 0.05 {M}⊙ of {}56{Ni} and that this mass is not very sensitive to central engine type. The morphology of the explosion can provide a powerful diagnostic of the properties of the central engine. In the absence of a circumstellar medium, these events are not very luminous, with peak bolometric magnitudes of {M}b˜ -16.5 due to low {}56{Ni} production.

Algorithm Engineering: Concepts and Practice

NASA Astrophysics Data System (ADS)

Chimani, Markus; Klein, Karsten

Over the last years the term algorithm engineering has become wide spread synonym for experimental evaluation in the context of algorithm development. Yet it implies even more. We discuss the major weaknesses of traditional "pen and paper" algorithmics and the ever-growing gap between theory and practice in the context of modern computer hardware and real-world problem instances. We present the key ideas and concepts of the central algorithm engineering cycle that is based on a full feedback loop: It starts with the design of the algorithm, followed by the analysis, implementation, and experimental evaluation. The results of the latter can then be reused for modifications to the algorithmic design, stronger or input-specific theoretic performance guarantees, etc. We describe the individual steps of the cycle, explaining the rationale behind them and giving examples of how to conduct these steps thoughtfully. Thereby we give an introduction to current algorithmic key issues like I/O-efficient or parallel algorithms, succinct data structures, hardware-aware implementations, and others. We conclude with two especially insightful success stories—shortest path problems and text search—where the application of algorithm engineering techniques led to tremendous performance improvements compared with previous state-of-the-art approaches.

RedeR: R/Bioconductor package for representing modular structures, nested networks and multiple levels of hierarchical associations

PubMed Central

2012-01-01

Visualization and analysis of molecular networks are both central to systems biology. However, there still exists a large technological gap between them, especially when assessing multiple network levels or hierarchies. Here we present RedeR, an R/Bioconductor package combined with a Java core engine for representing modular networks. The functionality of RedeR is demonstrated in two different scenarios: hierarchical and modular organization in gene co-expression networks and nested structures in time-course gene expression subnetworks. Our results demonstrate RedeR as a new framework to deal with the multiple network levels that are inherent to complex biological systems. RedeR is available from http://bioconductor.org/packages/release/bioc/html/RedeR.html. PMID:22531049

Near-IR 2D-spectroscopy of the 4''x 4'' region around the Active Galactic Nucleus of NGC 1068 with ISAAC/VLT

NASA Astrophysics Data System (ADS)

Galliano, E.; Alloin, D.

2002-10-01

New near-IR long slit spectroscopic data obtained with ISAAC on VLT/ANTU (ESO/Paranal) complement and extend our previously published near-IR data (Alloin et al. \\cite{all01}) to produce Brgamma and H2 emission line maps and line profile grids of the central 4'' x 4'' region surrounding the central engine of NGC 1068. The seeing quality together with the use of an 0.3'' wide slit and 0.3'' slit position offsets allow one to perform 2D-spectroscopy at a spatial resolution ~ 0.5''. Slit orientations (PA = 102 degr and PA = 12 degr) were chosen so as to match respectively the equatorial plane and the axis of the suspected molecular/dusty torus in NGC 1068. The selected wavelength range from 2.1 to 2.2μm is suitable to detect and analyze the Brgamma and H2 emission lines at a spectral resolution corresponding to 35km s-1. An asymmetric distribution of H2 emission around the continuum peak is observed. No H2 emission is detected at the location of the strong 2.2μm continuum core (coincident within error-bars with the central engine location), while two conspicuous knots of H2 emission are detected at about 1'' on each side of the central engine along PA = 90 degr, with a projected velocity difference of 140km s-1: this velocity jump has been interpreted in Alloin et al. (\\cite{all01}) as the signature of a rotating disk of molecular material. From this new data set, we find that only very low intensity Brgamma emission is detected at the location of the two main knots of H2 emission. Another knot with both H2 and Brgamma emission is detected to the North of the central engine, close to the radio source C where the small scale radio jet is redirected and close to the brightest [OIII] cloud NLR-B. It has a counterpart to the South, placed almost symmetrically with respect to the central engine, although mainly visible in the Brgamma emission. The northern and southern knots appear to be related to the ionization cone. At the achieved spectral resolution, the H2 emission line profiles appear highly asymmetric with their low velocity wing being systematically more extended than their high velocity wing. A simple way to account for the changes of the H2 line profiles (peak-shift with respect to the systemic velocity, width, asymmetry) over the entire 4'' x 4'' region, is to consider that a radial outflow is superimposed over the emission of the rotating molecular disk. We present a model of such a kinematical configuration and compare our predicted H2 emission profiles to the observed ones. Excitation of the H2 line is briefly discussed: X-ray irradiation from the central engine is found to be the most likely source of excitation. Given the fact that the material obscuring our direct view toward the central engine is Compton thick (NH >= 1024 {cm-2}), the observed location of the main H2 knots at a distance of 70 pc from the central engine suggests that the rotating molecular disk is warped. Based on observations collected at the ESO/Paranal 8 m UT1 telescope, Proposals 63.P-0167A & 66.B-0142A.

Physics from Time Variability of the VHE Blazar PKS 2155-304

NASA Astrophysics Data System (ADS)

Barres de Almeida, Ulisses

2010-10-01

Blazars are the principal extragalactic sources of very high energy gamma-ray emission in the Universe. These objects constitute a sub-class of Active Galactic Nuclei whose emission is dominated by Doppler boosted non-thermal radiation from plasma outflow- ing at relativistic speeds from the central engine. This plasma outflow happens in the form of large-scale collimated structures called jets, which can extend for Mpc in length and transport energy from the central engine of the galaxy to the larger scale intergalac- tic medium. Over thirty such sources have been discovered to date by ground-based gamma-ray telescopes such as H.E.S.S., and PKS 2155-304 is the prototypical southern- hemisphere representative of this population of objects. In this thesis we have studied in detail some aspects of the temporal variability of the jet emission from PKS 2155-304, combining coordinated observations across the electro- magnetic spectrum, from optical polarimetric measurements to X-ray and ground-based gamma-ray data. The temporal properties of the dataset allowed us to derive important physical information about the structure and emission mechanisms of the source and put constraints to the location of the sites of VHE emission and particle acceleration within the jet. We have also derived a sensitive statistical measure, called Kolmogorov distance, which we applied to the large outburst observed from PKS 2155-304 in July 2006, to de- rive the most stringent constraints to date on limits for the violation of Lorentz invariance induced by quantum-gravity effects from AGN measurements.

The Use of Executive Control Processes in Engineering Design by Engineering Students and Professional Engineers

ERIC Educational Resources Information Center

Dixon, Raymond A.; Johnson, Scott D.

2012-01-01

A cognitive construct that is important when solving engineering design problems is executive control process, or metacognition. It is a central feature of human consciousness that enables one "to be aware of, monitor, and control mental processes." The framework for this study was conceptualized by integrating the model for creative design, which…

40 CFR 1039.627 - What are the incentives for equipment manufacturers to use cleaner engines?

Code of Federal Regulations, 2012 CFR

2012-07-01

... engines. (e) In-use fuel. If the engine manufacturer certifies using ultra low-sulfur diesel fuel, you... commits to a central-fueling facility with ultra low-sulfur diesel fuel throughout its lifetime would meet... 1039: If the engine's maximum power is . . . And you install . . . Certified early to the . . . You may...

40 CFR 1039.627 - What are the incentives for equipment manufacturers to use cleaner engines?

Code of Federal Regulations, 2013 CFR

2013-07-01

... engines. (e) In-use fuel. If the engine manufacturer certifies using ultra low-sulfur diesel fuel, you... commits to a central-fueling facility with ultra low-sulfur diesel fuel throughout its lifetime would meet... 1039: If the engine's maximum power is . . . And you install . . . Certified early to the . . . You may...

40 CFR 1039.627 - What are the incentives for equipment manufacturers to use cleaner engines?

Code of Federal Regulations, 2014 CFR

2014-07-01

... engines. (e) In-use fuel. If the engine manufacturer certifies using ultra low-sulfur diesel fuel, you... commits to a central-fueling facility with ultra low-sulfur diesel fuel throughout its lifetime would meet... 1039: If the engine's maximum power is . . . And you install . . . Certified early to the . . . You may...

Relevance of Local Flexibility Near the Active Site for Enzymatic Catalysis: Biochemical Characterization and Engineering of Cellulase Cel5A From Bacillus agaradherans.

PubMed

Saavedra, Juan M; Azócar, Mauricio A; Rodríguez, Vida; Ramírez-Sarmiento, César A; Andrews, Barbara A; Asenjo, Juan A; Parra, Loreto P

2018-03-25

Detailed molecular mechanisms underpinning enzymatic reactions are still a central problem in biochemistry. The need for active site flexibility to sustain catalytic activity constitutes a notion of wide acceptance, although its direct influence remains to be fully understood. With the aim of studying the relationship between structural dynamics and enzyme catalysis, the cellulase Cel5A from Bacillus agaradherans is used as a model for in silico comparative analysis with mesophilic and psychrophilic counterparts. Structural features that determine flexibility are related to kinetic and thermodynamic parameters of catalysis. As a result, three specific positions in the vicinity of the active site of Cel5A are selected for protein engineering via site-directed mutagenesis. Three Cel5A variants are generated, N141L, A137Y and I102A/A137Y, showing a concomitant increase in the catalytic activity at low temperatures and a decrease in activation energy and activation enthalpy, similar to cold-active enzymes. These results are interpreted in structural terms by molecular dynamics simulations, showing that disrupting a hydrogen bond network in the vicinity of the active site increases local flexibility. These results provide a structural framework for explaining the changes in thermodynamic parameters observed between homologous enzymes with varying temperature adaptations. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The crystallization and structural analysis of cellulases (and other glycoside hydrolases): strategies and tactics.

PubMed

Roberts, Shirley M; Davies, Gideon J

2012-01-01

The three-dimensional (3-D) structures of cellulases, and other glycoside hydrolases, are a central feature of research in carbohydrate chemistry and biochemistry. 3-D structure is used to inform protein engineering campaigns, both academic and industrial, which are typically used to improve the stability or activity of an enzyme. Examples of classical protein engineering goals include higher thermal stability, reduced metal-ion dependency, detergent and protease resistance, decreased product inhibition, and altered specificity. 3-D structure may also be used to interpret the behavior of enzyme variants that are derived from screening or random mutagenesis approaches, with a view to establishing an iterative design process. In other areas, 3-D structure is used as one of the many tools to probe enzymatic catalysis, typically dovetailing with physical organic chemistry approaches to provide complete reaction mechanisms for enzymes by visualizing catalytic site interactions at different stages of the reaction. Such mechanistic insight is not only fundamentally important, impacting on inhibitor and drug design approaches with ramifications way beyond cellulose hydrolysis, but also provides the framework for the design of enzyme variants to use as biocatalysts for the synthesis of bespoke oligosaccharides. Here we review some of the strategies and tactics that may be applied to the X-ray structure solution of cellulases (and other carbohydrate-active enzymes). The general approach is first to decide why you are doing the work, then to establish correct domain boundaries for truncated constructs (typically the catalytic domain only), and finally to pursue crystallization of pure, homogeneous, and monodisperse protein with appropriate ligand and additive combinations. Cellulase-specific strategies are important for the delineation of domain boundaries, while glycoside hydrolases generally also present challenges and opportunities for the selection and optimization of ligands to both aid crystallization, and also provide structural and mechanistic insight. As the many roles for plant cell wall degrading enzymes increase, so does the need for rapid high-quality structure determination to provide a sound structural foundation for understanding mechanism and specificity, and for future protein engineering strategies. Copyright © 2012 Elsevier Inc. All rights reserved.

Control/structure interaction conceptual design tool

NASA Technical Reports Server (NTRS)

Briggs, Hugh C.

1990-01-01

The JPL Control/Structure Interaction Program is developing new analytical methods for designing micro-precision spacecraft with controlled structures. One of these, the Conceptual Design Tool, will illustrate innovative new approaches to the integration of multi-disciplinary analysis and design methods. The tool will be used to demonstrate homogeneity of presentation, uniform data representation across analytical methods, and integrated systems modeling. The tool differs from current 'integrated systems' that support design teams most notably in its support for the new CSI multi-disciplinary engineer. The design tool will utilize a three dimensional solid model of the spacecraft under design as the central data organization metaphor. Various analytical methods, such as finite element structural analysis, control system analysis, and mechanical configuration layout, will store and retrieve data from a hierarchical, object oriented data structure that supports assemblies of components with associated data and algorithms. In addition to managing numerical model data, the tool will assist the designer in organizing, stating, and tracking system requirements.

Coherent Turbulence Rig in the Engine Research Building

NASA Image and Video Library

1979-08-21

An engineer examines the Coherent Turbulence Rig in the Engine Research Building at the National Aeronautics and Space Administration (NASA) Lewis Research Center. Coherent turbulence occurs when waves of uniform size and alignment are present in airflow. Researchers at NASA Lewis were interested in determining the relation between the size of the waves and their heat transfer properties. The massive 4.25-acre Engine Research Building contains dozens of test cells, test stands, and altitude chambers. A powerful a collection of compressors and exhausters located in the central portion of the basement provides process air and exhaust for these test areas. This system is connected to similar process air systems in the laboratory’s other large test facilities. The Central Control Room coordinates this activity and communicates with the local utilities.

Toward Understanding the Fanaroff-Riley Dichotomy in Radio Source Morphology and Power

NASA Astrophysics Data System (ADS)

Baum, Stefi A.; Zirbel, Esther L.; O'Dea, Christopher P.

1995-09-01

In Paper I we presented the results of a study of the interrelationships between host galaxy magnitude, optical line luminosity, and radio luminosity in a large sample of Fanaroff-Riley classes 1 and 2 (FR 1 and FR 2) radio galaxies. We report several important differences between the FR 1 and FR 2 radio galaxies. At the same host galaxy magnitude or radio luminosity, the FR 2's produce substantially more optical line emission (by roughly an order of magnitude or more) than do FR 1's. Similarly, FR 2 sources produce orders of magnitude more line luminosity than do radio-quiet galaxies of the same optical magnitude, while FR 1 sources and radio-quiet galaxies of the same optical magnitude produce similar line luminosities. Combining these results with previous results from the literature, we conclude that while the emission-line gas in the FR 2's is indeed photoionized by a nuclear UV continuum source from the AGN, the emission-line gas in the FR 1's may be energized predominantly by processes associated with the host galaxy itself. The apparent lack of a strong UV continuum source from the central engine in FR 1 sources can be understood in two different ways. In the first scenario, FR l's are much more efficient at covering jet bulk kinetic energy into radio luminosity than FR 2's, such that an FR 1 has a much lower bolometric AGN luminosity (hence nuclear UV continuum source) than does an FR 2 of the same radio luminosity. We discuss the pros and cons of this model and conclude that the efficiency differences needed between FR 2 and FR 1 radio galaxies are quite large and may lead to difficulties with the interpretation since it would suggest that FR 2 radio source deposit very large amounts of kinetic energy into the ISM Intracluster Medium. However, this interpretation remains viable. Alternatively, it may be that the AGNs in FR 1 sources simply produce far less radiant UV energy than do those in FR 2 sources. That is, FR 1 sources may funnel a higher fraction of the total energy output from the AGNs into jet kinetic energy versus radiant energy than do FR 2 sources. If this interpretation is correct, then this suggests that there is a fundamental difference in the central engine and/or in the immediate "accretion region" around the engine in FR 1 and FR 2 radio galaxies. We note also the absence of FR 1 sources with nuclear broad line regions and suggest that the absence of the BLR is tied to the absence of the "isotropic" nuclear UV continuum source in FR 1 sources. We put forth the possibility that the FR 1/FR 2 dichotomy (i.e., the observed differences in the properties of low- and high-power radio sources) is due to qualitative differences in the structural properties of the central engines in these two types of sources. Following early work by Rees et al. (1982), we suggest the possibility that FR 1 sources are produced when the central engine is fed at a lower accretion rate, leading to the creation of a source in which the ratio of radiant to jet bulk kinetic energy is low, while FR 2 sources are produced when the central engine is fed at a higher accretion rate, causing the central engine to deposit a higher fraction of its energy in radiant energy. We further suggest the possibility that associated differences in the spin properties of the central black hole between FR 1 (lower spin) and FR 2 (higher spin) sources may be responsible for the different collimation properties and Mach numbers of the jets produced by these two types of radio-loud galaxies. This scenario, although currently clearly speculative, is nicely consistent with our current picture of the triggering, feeding, environments, and evolution of powerful radio galaxies. This model allows for evolution of these properties with time for example, the mass accretion rate and BH spin may decline with time causing an FR 2 radio source or quasar to evolve into a FR 1 radio source.

Minimalistic peptide supramolecular co-assembly: expanding the conformational space for nanotechnology.

PubMed

Makam, Pandeeswar; Gazit, Ehud

2018-05-21

Molecular self-assembly is a ubiquitous process in nature and central to bottom-up nanotechnology. In particular, the organization of peptide building blocks into ordered supramolecular structures has gained much interest due to the unique properties of the products, including biocompatibility, chemical and structural diversity, robustness and ease of large-scale synthesis. In addition, peptides, as short as dipeptides, contain all the molecular information needed to spontaneously form well-ordered structures at both the nano- and the micro-scale. Therefore, peptide supramolecular assembly has been effectively utilized to produce novel materials with tailored properties for various applications in the fields of material science, engineering, medicine, and biology. To further expand the conformational space of peptide assemblies in terms of structural and functional complexity, multicomponent (two or more) peptide supramolecular co-assembly has recently evolved as a promising extended approach, similar to the structural diversity of natural sequence-defined biopolymers (proteins) as well as of synthetic covalent co-polymers. The use of this methodology was recently demonstrated in various applications, such as nanostructure physical dimension control, the creation of non-canonical complex topologies, mechanical strength modulation, the design of light harvesting soft materials, fabrication of electrically conducting devices, induced fluorescence, enzymatic catalysis and tissue engineering. In light of these significant advancements in the field of peptide supramolecular co-assembly in the last few years, in this tutorial review, we provide an updated overview and future prospects of this emerging subject.

Bio-mimetic hollow scaffolds for long bone replacement

NASA Astrophysics Data System (ADS)

Müller, Bert; Deyhle, Hans; Fierz, Fabienne C.; Irsen, Stephan H.; Yoon, Jin Y.; Mushkolaj, Shpend; Boss, Oliver; Vorndran, Elke; Gburek, Uwe; Degistirici, Özer; Thie, Michael; Leukers, Barbara; Beckmann, Felix; Witte, Frank

2009-08-01

The tissue engineering focuses on synthesis or regeneration of tissues and organs. The hierarchical structure of nearly all porous scaffolds on the macro, micro- and nanometer scales resembles that of engineering foams dedicated for technical applications, but differ from the complex architecture of long bone. A major obstacle of scaffold architecture in tissue regeneration is the limited cell infiltration as the result of the engineering approaches. The biological cells seeded on the three-dimensional constructs are finally only located on the scaffold's periphery. This paper reports on the successful realization of calcium phosphate scaffolds with an anatomical architecture similar to long bones. Two base materials, namely nano-porous spray-dried hydroxyapatite hollow spheres and tri-calcium phosphate powder, were used to manufacture cylindrically shaped, 3D-printed scaffolds with micro-passages and one central macro-canal following the general architecture of long bones. The macro-canal is built for the surgical placement of nerves or larger blood vessels. The micro-passages allow for cell migration and capillary formation through the entire scaffold. Finally, the nanoporosity is essential for the molecule transport crucial for signaling, any cell nutrition and waste removal.

Light Water Reactor Sustainability Program: Risk-Informed Safety Margins Characterization (RISMC) Pathway Technical Program Plan

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, Curtis; Rabiti, Cristian; Martineau, Richard

Safety is central to the design, licensing, operation, and economics of Nuclear Power Plants (NPPs). As the current Light Water Reactor (LWR) NPPs age beyond 60 years, there are possibilities for increased frequency of Systems, Structures, and Components (SSCs) degradations or failures that initiate safety-significant events, reduce existing accident mitigation capabilities, or create new failure modes. Plant designers commonly “over-design” portions of NPPs and provide robustness in the form of redundant and diverse engineered safety features to ensure that, even in the case of well-beyond design basis scenarios, public health and safety will be protected with a very high degreemore » of assurance. This form of defense-in-depth is a reasoned response to uncertainties and is often referred to generically as “safety margin.” Historically, specific safety margin provisions have been formulated, primarily based on “engineering judgment.”« less

Preclinical evidence supporting the clinical development of central pattern generator-modulating therapies for chronic spinal cord-injured patients

PubMed Central

2014-01-01

Ambulation or walking is one of the main gaits of locomotion. In terrestrial animals, it may be defined as a series of rhythmic and bilaterally coordinated movement of the limbs which creates a forward movement of the body. This applies regardless of the number of limbs—from arthropods with six or more limbs to bipedal primates. These fundamental similarities among species may explain why comparable neural systems and cellular properties have been found, thus far, to control in similar ways locomotor rhythm generation in most animal models. The aim of this article is to provide a comprehensive review of the known structural and functional features associated with central nervous system (CNS) networks that are involved in the control of ambulation and other stereotyped motor patterns—specifically Central Pattern Generators (CPGs) that produce basic rhythmic patterned outputs for locomotion, micturition, ejaculation, and defecation. Although there is compelling evidence of their existence in humans, CPGs have been most studied in reduced models including in vitro isolated preparations, genetically-engineered mice and spinal cord-transected animals. Compared with other structures of the CNS, the spinal cord is generally considered as being well-preserved phylogenetically. As such, most animal models of spinal cord-injured (SCI) should be considered as valuable tools for the development of novel pharmacological strategies aimed at modulating spinal activity and restoring corresponding functions in chronic SCI patients. PMID:24910602

Environments for Fostering Effective Critical Thinking in Geotechnical Engineering Education (Geo-EFFECTs)

ERIC Educational Resources Information Center

Pierce, Charles E.; Gassman, Sarah L.; Huffman, Jeffrey T.

2013-01-01

This paper describes the development, implementation, and assessment of instructional materials for geotechnical engineering concepts using the Environments for Fostering Effective Critical Thinking (EFFECTs) pedagogical framework. The central learning goals of engineering EFFECTs are to (i) improve the understanding and retention of a specific…

48 CFR Appendix A to Part 1219 - Appendix A to Part 1219

Code of Federal Regulations, 2010 CFR

2010-10-01

...* FPDS products and service code (1) Engineering Development AT94 (2) Systems Engineering Services (Only) R414 (3) Radio/TV Communication Equipment (except airborne) 5820 (4) Maintenance, Repair, and Rebuilding of engines, turbines, components and weapons equipment J028/J010 (5) ADP Central Processing Units...

The 10 MWe Solar Thermal Central Receiver Pilot Plant: Solar facilities design integration. Pilot-plant station manual (RADL Item 2-1). Volume 1: System description

NASA Astrophysics Data System (ADS)

1982-09-01

The complete Barstow Solar Pilot Plant is described. The plant requirements and general description are presented, the mechanical, electric power, and control and instrumentation systems as well as civil engineering and structural aspects and the station buildings are described. Included in the mechanical systems are the heliostats, receiver, thermal storage system, beam characterization system, steam, water, nitrogen, and compressed air systems, chemical feed system, fire protection system, drains, sumps and the waste disposal systems, and heating, ventilating, and air conditioning systems.

Distributed and Centralized Conflict Management Under Traffic Flow Management Constraints

NASA Technical Reports Server (NTRS)

Feron, Eric; Bilimoria, Karl (Technical Monitor)

2003-01-01

Current air transportation in the United States relies on a system born half a century ago. While demand for air travel has kept increasing over the years, technologies at the heart of the National Airspace System (NAS) have not been able to follow an adequate evolution. For instance, computers used to centralize flight data in airspace sectors run a software developed in 1972. Safety, as well as certification and portability issues arise as major obstacles for the improvement of the system. The NAS is a structure that has never been designed, but has rather evolved over time. This has many drawbacks, mainly due to a lack of integration and engineering leading to many inefficiencies and losses of performance. To improve the operations, understanding of this complex needs to be built up to a certain level. This work presents research done on Air Traffic Management (ATM) at the level of the en-route sector.

Structural Engineering Managers - Innovation Challenges for their Skills

NASA Astrophysics Data System (ADS)

Linkeschová, D.; Tichá, A.

2015-11-01

The profession of a structural engineer is highly responsible, because the consequences of a structural engineer's errors result not only in economic damage to the property and often irreversible damage to the environment, they can also lead to direct loss of lives. In the current turbulent, dynamically developing society the managerial methods of structural engineers should not stagnate at the level of the last century applications. This paper deals with the challenges which the ongoing century poses to structural engineers and managers. It compares the results of research regarding the current state of managerial skills of structural engineers in Czech building companies to the defined skills of the 21st century's managers according to the global research programme ITL Research and according to the Vision for the Future of Structural Engineering, drawn up by Structural Engineering Institute - SEI ASCE.

Integrated optomechanical analysis and testing software development at MIT Lincoln Laboratory

NASA Astrophysics Data System (ADS)

Stoeckel, Gerhard P.; Doyle, Keith B.

2013-09-01

Advanced analytical software capabilities are being developed to advance the design of prototypical hardware in the Engineering Division at MIT Lincoln Laboratory. The current effort is focused on the integration of analysis tools tailored to the work flow, organizational structure, and current technology demands. These tools are being designed to provide superior insight into the interdisciplinary behavior of optical systems and enable rapid assessment and execution of design trades to optimize the design of optomechanical systems. The custom software architecture is designed to exploit and enhance the functionality of existing industry standard commercial software, provide a framework for centralizing internally developed tools, and deliver greater efficiency, productivity, and accuracy through standardization, automation, and integration. Specific efforts have included the development of a feature-rich software package for Structural-Thermal-Optical Performance (STOP) modeling, advanced Line Of Sight (LOS) jitter simulations, and improved integration of dynamic testing and structural modeling.

14 CFR 33.23 - Engine mounting attachments and structure.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Engine mounting attachments and structure... mounting attachments and structure. (a) The maximum allowable limit and ultimate loads for engine mounting attachments and related engine structure must be specified. (b) The engine mounting attachments and related...

Laser-induced incandescence measurements in a fired diesel engine at 3 kHz

NASA Astrophysics Data System (ADS)

Boxx, I. G.; Heinold, O.; Geigle, K. P.

2015-01-01

Laser-induced incandescence (LII) was performed at 3 kHz in an optically accessible cylinder of a fired diesel engine using a commercially available diode-pumped solid-state laser and an intensified CMOS camera. The resulting images, acquired every 3° of crank angle, enabled the spatiotemporal tracking of soot structures during the expansion/exhaust stroke of the engine cycle. The image sequences demonstrate that soot tends to form in thin sheets that propagate and interact with the in-cylinder flow. These sheets tend to align parallel to the central axis of the cylinder and are frequently wrapped into conical spirals by aerodynamic swirl. Most of the soot is observed well away from the cylinder walls. Quantitative soot measurements were beyond the scope of this study but the results demonstrate the practical utility of using kHz-rate LII to acquire ensemble-averaged statistical data with high crank angle resolution over a complete engine cycle. Based on semi-quantitative measures of soot distribution, it was possible to identify soot dynamics related to incomplete charge exchange. This study shows that long-duration, multi-kHz acquisition rate LII measurements are viable in a fired diesel engine with currently available laser and camera technology, albeit only in the expansion and exhaust phase of the cycle at present. Furthermore, such measurements yield useful insight into soot dynamics and therefore constitute an important new tool for the development and optimization of diesel engine technology.

An Improved Forensic Science Information Search.

PubMed

Teitelbaum, J

2015-01-01

Although thousands of search engines and databases are available online, finding answers to specific forensic science questions can be a challenge even to experienced Internet users. Because there is no central repository for forensic science information, and because of the sheer number of disciplines under the forensic science umbrella, forensic scientists are often unable to locate material that is relevant to their needs. The author contends that using six publicly accessible search engines and databases can produce high-quality search results. The six resources are Google, PubMed, Google Scholar, Google Books, WorldCat, and the National Criminal Justice Reference Service. Carefully selected keywords and keyword combinations, designating a keyword phrase so that the search engine will search on the phrase and not individual keywords, and prompting search engines to retrieve PDF files are among the techniques discussed. Copyright © 2015 Central Police University.

Improving Distributed Diagnosis Through Structural Model Decomposition

NASA Technical Reports Server (NTRS)

Bregon, Anibal; Daigle, Matthew John; Roychoudhury, Indranil; Biswas, Gautam; Koutsoukos, Xenofon; Pulido, Belarmino

2011-01-01

Complex engineering systems require efficient fault diagnosis methodologies, but centralized approaches do not scale well, and this motivates the development of distributed solutions. This work presents an event-based approach for distributed diagnosis of abrupt parametric faults in continuous systems, by using the structural model decomposition capabilities provided by Possible Conflicts. We develop a distributed diagnosis algorithm that uses residuals computed by extending Possible Conflicts to build local event-based diagnosers based on global diagnosability analysis. The proposed approach is applied to a multitank system, and results demonstrate an improvement in the design of local diagnosers. Since local diagnosers use only a subset of the residuals, and use subsystem models to compute residuals (instead of the global system model), the local diagnosers are more efficient than previously developed distributed approaches.

14. Drawing showing stress for central viaduct, Walworth Run portion ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

14. Drawing showing stress for central viaduct, Walworth Run portion 1885. Drawing courtesy Engineering Department, City of Cleveland. - Abbey Avenue Viaduct, Spanning Walworth Valley at Abbey Avenue, Cleveland, Cuyahoga County, OH

Computer graphics and the graphic artist

NASA Technical Reports Server (NTRS)

Taylor, N. L.; Fedors, E. G.; Pinelli, T. E.

1985-01-01

A centralized computer graphics system is being developed at the NASA Langley Research Center. This system was required to satisfy multiuser needs, ranging from presentation quality graphics prepared by a graphic artist to 16-mm movie simulations generated by engineers and scientists. While the major thrust of the central graphics system was directed toward engineering and scientific applications, hardware and software capabilities to support the graphic artists were integrated into the design. This paper briefly discusses the importance of computer graphics in research; the central graphics system in terms of systems, software, and hardware requirements; the application of computer graphics to graphic arts, discussed in terms of the requirements for a graphic arts workstation; and the problems encountered in applying computer graphics to the graphic arts. The paper concludes by presenting the status of the central graphics system.

Engine Structures Modeling Software System (ESMOSS)

NASA Technical Reports Server (NTRS)

1991-01-01

Engine Structures Modeling Software System (ESMOSS) is the development of a specialized software system for the construction of geometric descriptive and discrete analytical models of engine parts, components, and substructures which can be transferred to finite element analysis programs such as NASTRAN. The NASA Lewis Engine Structures Program is concerned with the development of technology for the rational structural design and analysis of advanced gas turbine engines with emphasis on advanced structural analysis, structural dynamics, structural aspects of aeroelasticity, and life prediction. Fundamental and common to all of these developments is the need for geometric and analytical model descriptions at various engine assembly levels which are generated using ESMOSS.

Communication Needs Assessment for Distributed Turbine Engine Control

NASA Technical Reports Server (NTRS)

Culley, Dennis E.; Behbahani, Alireza R.

2008-01-01

Control system architecture is a major contributor to future propulsion engine performance enhancement and life cycle cost reduction. The control system architecture can be a means to effect net weight reduction in future engine systems, provide a streamlined approach to system design and implementation, and enable new opportunities for performance optimization and increased awareness about system health. The transition from a centralized, point-to-point analog control topology to a modular, networked, distributed system is paramount to extracting these system improvements. However, distributed engine control systems are only possible through the successful design and implementation of a suitable communication system. In a networked system, understanding the data flow between control elements is a fundamental requirement for specifying the communication architecture which, itself, is dependent on the functional capability of electronics in the engine environment. This paper presents an assessment of the communication needs for distributed control using strawman designs and relates how system design decisions relate to overall goals as we progress from the baseline centralized architecture, through partially distributed and fully distributed control systems.

Self-recognition in corals facilitates deep-sea habitat engineering

USGS Publications Warehouse

Hennige, Sebastian J; Morrison, Cheryl L.; Form, Armin U.; Buscher, Janina; Kamenos, Nicholas A.; Roberts, J. Murray

2014-01-01

The ability of coral reefs to engineer complex three-dimensional habitats is central to their success and the rich biodiversity they support. In tropical reefs, encrusting coralline algae bind together substrates and dead coral framework to make continuous reef structures, but beyond the photic zone, the cold-water coral Lophelia pertusa also forms large biogenic reefs, facilitated by skeletal fusion. Skeletal fusion in tropical corals can occur in closely related or juvenile individuals as a result of non-aggressive skeletal overgrowth or allogeneic tissue fusion, but contact reactions in many species result in mortality if there is no ‘self-recognition’ on a broad species level. This study reveals areas of ‘flawless’ skeletal fusion in Lophelia pertusa, potentially facilitated by allogeneic tissue fusion, are identified as having small aragonitic crystals or low levels of crystal organisation, and strong molecular bonding. Regardless of the mechanism, the recognition of ‘self’ between adjacent L. pertusa colonies leads to no observable mortality, facilitates ecosystem engineering and reduces aggression-related energetic expenditure in an environment where energy conservation is crucial. The potential for self-recognition at a species level, and subsequent skeletal fusion in framework-forming cold-water corals is an important first step in understanding their significance as ecological engineers in deep-seas worldwide.

Mobility Data Analytics Center.

DOT National Transportation Integrated Search

2016-01-01

Mobility Data Analytics Center aims at building a centralized data engine to efficiently manipulate : large-scale data for smart decision making. Integrating and learning the massive data are the key to : the data engine. The ultimate goal of underst...

14 CFR 183.29 - Designated engineering representatives.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 3 2012-01-01 2012-01-01 false Designated engineering representatives. 183... § 183.29 Designated engineering representatives. (a) A structural engineering representative may approve structural engineering information and other structural considerations within limits prescribed by and under...

14 CFR 183.29 - Designated engineering representatives.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 3 2014-01-01 2014-01-01 false Designated engineering representatives. 183... § 183.29 Designated engineering representatives. (a) A structural engineering representative may approve structural engineering information and other structural considerations within limits prescribed by and under...

14 CFR 183.29 - Designated engineering representatives.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 3 2011-01-01 2011-01-01 false Designated engineering representatives. 183... § 183.29 Designated engineering representatives. (a) A structural engineering representative may approve structural engineering information and other structural considerations within limits prescribed by and under...

14 CFR 183.29 - Designated engineering representatives.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 3 2013-01-01 2013-01-01 false Designated engineering representatives. 183... § 183.29 Designated engineering representatives. (a) A structural engineering representative may approve structural engineering information and other structural considerations within limits prescribed by and under...

14 CFR 183.29 - Designated engineering representatives.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Designated engineering representatives. 183... § 183.29 Designated engineering representatives. (a) A structural engineering representative may approve structural engineering information and other structural considerations within limits prescribed by and under...

Structural engineering masters level education framework of knowledge for the needs of initial professional practice

NASA Astrophysics Data System (ADS)

Balogh, Zsuzsa Enriko

For at least the last decade, engineering, civil engineering, along with structural engineering as a profession within civil engineering, have and continue to face an emerging need for "Raising the Bar" of preparedness of young engineers seeking to become practicing professional engineers. The present consensus of the civil engineering profession is that the increasing need for broad and in-depth knowledge should require the young structural engineers to have at least a Masters-Level education. This study focuses on the Masters-Level preparedness in the structural engineering area within the civil engineering field. It follows much of the methodology used in the American Society of Civil Engineers (ASCE) Body of Knowledge determination for civil engineering and extends this type of study to better define the portion of the young engineers preparation beyond the undergraduate program for one specialty area of civil engineering. The objective of this research was to create a Framework of Knowledge for the young engineer which identifies and recognizes the needs of the profession, along with the profession's expectations of how those needs can be achieved in the graduate-level academic setting, in the practice environment, and through lifelong learning opportunities with an emphasis on the initial five years experience past completion of a Masters program in structural engineering. This study applied a modified Delphi method to obtain the critical information from members of the structural engineering profession. The results provide a Framework of Knowledge which will be useful to several groups seeking to better ensure the preparedness of the future young structural engineers at the Masters-Level.

UNIFYING THE ZOO OF JET-DRIVEN STELLAR EXPLOSIONS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lazzati, Davide; Blackwell, Christopher H.; Morsony, Brian J.

We present a set of numerical simulations of stellar explosions induced by relativistic jets emanating from a central engine sitting at the center of compact, dying stars. We explore a wide range of durations of the central engine activity, two candidate stellar progenitors, and two possible values of the total energy release. We find that even if the jets are narrowly collimated, their interaction with the star unbinds the stellar material, producing a stellar explosion. We also find that the outcome of the explosion can be very different depending on the duration of the engine activity. Only the longest-lasting enginesmore » result in successful gamma-ray bursts. Engines that power jets only for a short time result in relativistic supernova (SN) explosions, akin to observed engine-driven SNe such as SN2009bb. Engines with intermediate durations produce weak gamma-ray bursts, with properties similar to nearby bursts such as GRB 980425. Finally, we find that the engines with the shortest durations, if they exist in nature, produce stellar explosions that lack sizable amounts of relativistic ejecta and are therefore dynamically indistinguishable from ordinary core-collapse SNe.« less

Civil engineering reference guide

DOE Office of Scientific and Technical Information (OSTI.GOV)

Merritt, F.S.

1986-01-01

The civil engineering reference guide contains the following: Structural theory. Structural steel design. Concrete design and construction. Wood design and construction. Bridge engineering. Geotechnical engineering. Water engineering. Environmental engineering. Surveying.

Evaluation of thresholding techniques for segmenting scaffold images in tissue engineering

NASA Astrophysics Data System (ADS)

Rajagopalan, Srinivasan; Yaszemski, Michael J.; Robb, Richard A.

2004-05-01

Tissue engineering attempts to address the ever widening gap between the demand and supply of organ and tissue transplants using natural and biomimetic scaffolds. The regeneration of specific tissues aided by synthetic materials is dependent on the structural and morphometric properties of the scaffold. These properties can be derived non-destructively using quantitative analysis of high resolution microCT scans of scaffolds. Thresholding of the scanned images into polymeric and porous phase is central to the outcome of the subsequent structural and morphometric analysis. Visual thresholding of scaffolds produced using stochastic processes is inaccurate. Depending on the algorithmic assumptions made, automatic thresholding might also be inaccurate. Hence there is a need to analyze the performance of different techniques and propose alternate ones, if needed. This paper provides a quantitative comparison of different thresholding techniques for segmenting scaffold images. The thresholding algorithms examined include those that exploit spatial information, locally adaptive characteristics, histogram entropy information, histogram shape information, and clustering of gray-level information. The performance of different techniques was evaluated using established criteria, including misclassification error, edge mismatch, relative foreground error, and region non-uniformity. Algorithms that exploit local image characteristics seem to perform much better than those using global information.

The role of hardware in learning engineering fundamentals: An empirical study of engineering design and product analysis activity

NASA Astrophysics Data System (ADS)

Brereton, Margot Felicity

A series of short engineering exercises and design projects was created to help students learn to apply abstract knowledge to physical experiences with hardware. The exercises involved designing machines from kits of materials and dissecting and analyzing familiar household products. Students worked in teams. During the activities students brought their knowledge of engineering fundamentals to bear. Videotape analysis was used to identify and characterize the ways in which hardware contributed to learning fundamental concepts. Structural and qualitative analyses of videotaped activities were undertaken. Structural analysis involved counting the references to theory and hardware and the extent of interleaving of references in activity. The analysis found that there was much more discussion linking fundamental concepts to hardware in some activities than in others. The analysis showed that the interleaving of references to theory and hardware in activity is observable and quantifiable. Qualitative analysis was used to investigate the dialog linking concepts and hardware. Students were found to advance their designs and their understanding of engineering fundamentals through a negotiation process in which they pitted abstract concepts against hardware behavior. Through this process students sorted out theoretical assumptions and causal relations. In addition they discovered design assumptions, functional connections and physical embodiments of abstract concepts in hardware, developing a repertoire of familiar hardware components and machines. Hardware was found to be integral to learning, affecting the course of inquiry and the dynamics of group interaction. Several case studies are presented to illustrate the processes at work. The research illustrates the importance of working across the boundary between abstractions and experiences with hardware in order to learn engineering and physical sciences. The research findings are: (a) the negotiation process by which students discover fundamental concepts in hardware (and three central causes of negotiation breakdown); (b) a characterization of the ways that material systems contribute to learning activities, (the seven roles of hardware in learning); (c) the characteristics of activities that support discovering fundamental concepts in hardware (plus several engineering exercises); (d) a research methodology to examine how students learn in practice.

Efficient weighting strategy for enhancing synchronizability of complex networks

NASA Astrophysics Data System (ADS)

Wang, Youquan; Yu, Feng; Huang, Shucheng; Tu, Juanjuan; Chen, Yan

2018-04-01

Networks with high propensity to synchronization are desired in many applications ranging from biology to engineering. In general, there are two ways to enhance the synchronizability of a network: link rewiring and/or link weighting. In this paper, we propose a new link weighting strategy based on the concept of the neighborhood subgroup. The neighborhood subgroup of a node i through node j in a network, i.e. Gi→j, means that node u belongs to Gi→j if node u belongs to the first-order neighbors of j (not include i). Our proposed weighting schema used the local and global structural properties of the networks such as the node degree, betweenness centrality and closeness centrality measures. We applied the method on scale-free and Watts-Strogatz networks of different structural properties and show the good performance of the proposed weighting scheme. Furthermore, as model networks cannot capture all essential features of real-world complex networks, we considered a number of undirected and unweighted real-world networks. To the best of our knowledge, the proposed weighting strategy outperformed the previously published weighting methods by enhancing the synchronizability of these real-world networks.

Jet Engine Control Using Ethernet with a BRAIN (Postprint)

DTIC Science & Technology

2008-07-01

current communications may be mitigated. 15. SUBJECT TERMS BRAIN, Braided Ring Availability Integrity Network, Gas turbine, FADEC , disturbed...urrent state of the art engine controls have converged on the notion of the Full Authority Digital Engine Control ( FADEC ), which consists of a centralized...is completely dependent on the proper operation of the controller. In current systems, the FADEC is often located on the relatively cool engine fan

Computational Infrastructure for Engine Structural Performance Simulation

NASA Technical Reports Server (NTRS)

Chamis, Christos C.

1997-01-01

Select computer codes developed over the years to simulate specific aspects of engine structures are described. These codes include blade impact integrated multidisciplinary analysis and optimization, progressive structural fracture, quantification of uncertainties for structural reliability and risk, benefits estimation of new technology insertion and hierarchical simulation of engine structures made from metal matrix and ceramic matrix composites. Collectively these codes constitute a unique infrastructure readiness to credibly evaluate new and future engine structural concepts throughout the development cycle from initial concept, to design and fabrication, to service performance and maintenance and repairs, and to retirement for cause and even to possible recycling. Stated differently, they provide 'virtual' concurrent engineering for engine structures total-life-cycle-cost.

40 CFR 52.1126 - Control strategy: Sulfur oxides.

Code of Federal Regulations, 2012 CFR

2012-07-01

... granted by the Massachusetts Department of Environmental Quality Engineering.) Massachusetts Mutual Life... stack). Central Massachusetts APCD Borden, Inc., Chemical Division, Leominster (conditioned upon first... Department of Environmental Quality Engineering.). Gardner State Hospital, Gardner. Grafton State Hospital...

40 CFR 52.1126 - Control strategy: Sulfur oxides.

Code of Federal Regulations, 2010 CFR

2010-07-01

... granted by the Massachusetts Department of Environmental Quality Engineering.) Massachusetts Mutual Life... stack). Central Massachusetts APCD Borden, Inc., Chemical Division, Leominster (conditioned upon first... Department of Environmental Quality Engineering.). Gardner State Hospital, Gardner. Grafton State Hospital...

40 CFR 52.1126 - Control strategy: Sulfur oxides.

Code of Federal Regulations, 2011 CFR

2011-07-01

... granted by the Massachusetts Department of Environmental Quality Engineering.) Massachusetts Mutual Life... stack). Central Massachusetts APCD Borden, Inc., Chemical Division, Leominster (conditioned upon first... Department of Environmental Quality Engineering.). Gardner State Hospital, Gardner. Grafton State Hospital...

75 FR 883 - Environmental Impact Statement; Maricopa County, AZ

Federal Register 2010, 2011, 2012, 2013, 2014

2010-01-06

...: Kenneth Davis, Senior Engineering Manager for Operations, Federal Highway Administration, 4000 N. Central..., 2009. Kenneth H. Davis, Senior Engineering Manager for Operations, Federal Highway Administration... Research, Planning and Construction. The regulations implementing Executive Order 12372 regarding...

The bungling giant: Atomic Energy Canada Limited and next-generation nuclear technology, 1980--1994

NASA Astrophysics Data System (ADS)

Slater, Ian James

From 1980--1994 Atomic Energy Canada Limited (AECL), the Crown Corporation responsible for the development of nuclear technology in Canada, ventured into the market for small-scale, decentralized power systems with the Slowpoke Energy System (SES), a 10MW nuclear reactor for space heating in urban and remote areas. The SES was designed to be "passively" or "inherently" safe, such that even the most catastrophic failure of the system would not result in a serious accident (e.g. a meltdown or an explosion). This Canadian initiative, a beneficiary of the National Energy Program, was the first and by far the most successful attempt at a passively safe, decentralized nuclear power system anywhere in the world. Part one uses archival documentation and interviews with project leaders to reconstruct the history of the SES. The standard explanations for the failure of the project, cheap oil, public resistance to the technology, and lack of commercial expertise, are rejected. Part two presents an alternative explanation for the failure of AECL to commercialize the SES. In short, technological momentum towards large-scale nuclear designs led to structural restrictions for the SES project. These restrictions manifested themselves internally to the company (e.g., marginalization of the SES) and externally to the company (e.g., licensing). In part three, the historical lessons of the SES are used to refine one of the central tenets of Popper's political philosophy, "piecemeal social engineering." Popper's presentation of the idea is lacking in detail; the analysis of the SES provides some empirical grounding for the concept. I argue that the institutions surrounding traditional nuclear power represent a form utopian social engineering, leading to consequences such as the suspension of civil liberties to guarantee security of the technology. The SES project was an example of a move from the utopian social engineering of large-scale centralized nuclear technology to the piecemeal social engineering of small-scale, safer and simpler decentralized nuclear heating.

29. OVERVIEW OF CENTRAL PART, TO WEST, SHOWING CLERESTORY WINDOWS. ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

29. OVERVIEW OF CENTRAL PART, TO WEST, SHOWING CLERESTORY WINDOWS. THE WALL AT REAR IS RECENT, SEPARATING TWO TENANTS' SPACES. - United Engineering Company Shipyard, Inspection & Repair Shops, 2900 Main Street, Alameda, Alameda County, CA

The Education of Future Aeronautical Engineers: Conceiving, Designing, Implementing and Operating

ERIC Educational Resources Information Center

Crawley, Edward F.; Brodeur, Doris R.; Soderholm, Diane H.

2008-01-01

This paper will outline answers to the two central questions regarding improving engineering education: (1) What is the full set of knowledge, skills, and attitudes that engineering students should possess as they leave the university, and at what level of proficiency?; and (2) How can we do better at ensuring that students learn these skills? The…

1. View of engine terminal complex looking westnorthwest from east ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. View of engine terminal complex looking west-northwest from east side of Phillips Drive. Shown are (left to right) the south roundhouse, the machine and blacksmith shops, the storehouse, the oil house, and the coaling sation (behind the oil house in this view). - Central Railroad of New Jersey, Engine Terminal, Jersey City, Hudson County, NJ

32. Photograph of line drawing in possession of the Engineering ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

32. Photograph of line drawing in possession of the Engineering Division of the Directorate of Engineering and Housing, Watervliet Arsenal, New York. SECTIONAL ELEVATIONS OF CENTRAL SECTION AND NORTH WING, UNDATED. SIGNED BY A. VICTORIN. (LEFT HALF OF DRAWING) - Watervliet Arsenal, Building No. 110, Hagner Road between Schull & Whittemore Roads, Watervliet, Albany County, NY

33. Photograph of line drawing in possession of the Engineering ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

33. Photograph of line drawing in possession of the Engineering Division of the Directorate of Engineering and Housing, Watervliet Arsenal, New York. SECTIONAL ELEVATIONS OF CENTRAL SECTION AND NORTH WING, UNDATED. SIGNED BY A. VICTORIN. (RIGHT HALF OF DRAWING) - Watervliet Arsenal, Building No. 110, Hagner Road between Schull & Whittemore Roads, Watervliet, Albany County, NY

Engine-induced structural-borne noise in a general aviation aircraft

NASA Technical Reports Server (NTRS)

Unruh, J. F.; Scheidt, D. C.; Pomerening, D. J.

1979-01-01

Structural borne interior noise in a single engine general aviation aircraft was studied to determine the importance of engine induced structural borne noise and to determine the necessary modeling requirements for the prediction of structural borne interior noise. Engine attached/detached ground test data show that engine induced structural borne noise is a primary interior noise source for the single engine test aircraft, cabin noise is highly influenced by responses at the propeller tone, and cabin acoustic resonances can influence overall noise levels. Results from structural and acoustic finite element coupled models of the test aircraft show that wall flexibility has a strong influence on fundamental cabin acoustic resonances, the lightweight fuselage structure has a high modal density, and finite element analysis procedures are appropriate for the prediction of structural borne noise.

Foundations for offshore wind turbines.

PubMed

Byrne, B W; Houlsby, G T

2003-12-15

An important engineering challenge of today, and a vital one for the future, is to develop and harvest alternative sources of energy. This is a firm priority in the UK, with the government setting a target of 10% of electricity from renewable sources by 2010. A component central to this commitment will be to harvest electrical power from the vast energy reserves offshore, through wind turbines or current or wave power generators. The most mature of these technologies is that of wind, as much technology transfer can be gained from onshore experience. Onshore wind farms, although supplying 'green energy', tend to provoke some objections on aesthetic grounds. These objections can be countered by locating the turbines offshore, where it will also be possible to install larger capacity turbines, thus maximizing the potential of each wind farm location. This paper explores some civil-engineering problems encountered for offshore wind turbines. A critical component is the connection of the structure to the ground, and in particular how the load applied to the structure is transferred safely to the surrounding soil. We review previous work on the design of offshore foundations, and then present some simple design calculations for sizing foundations and structures appropriate to the wind-turbine problem. We examine the deficiencies in the current design approaches, and the research currently under way to overcome these deficiencies. Designs must be improved so that these alternative energy sources can compete economically with traditional energy suppliers.

Solar thermal electricity generation

NASA Astrophysics Data System (ADS)

Gasemagha, Khairy Ramadan

1993-01-01

This report presents the results of modeling the thermal performance and economic feasibility of large (utility scale) and small solar thermal power plants for electricity generation. A number of solar concepts for power systems applications have been investigated. Each concept has been analyzed over a range of plant power ratings from 1 MW(sub e) to 300 MW(sub e) and over a range of capacity factors from a no-storage case (capacity factor of about 0.25 to 0.30) up to intermediate load capacity factors in the range of 0.46 to 0.60. The solar plant's economic viability is investigated by examining the effect of various parameters on the plant costs (both capital and O & M) and the levelized energy costs (LEC). The cost components are reported in six categories: collectors, energy transport, energy storage, energy conversion, balance of plant, and indirect/contingency costs. Concentrator and receiver costs are included in the collector category. Thermal and electric energy transport costs are included in the energy transport category. Costs for the thermal or electric storage are included in the energy storage category; energy conversion costs are included in the energy conversion category. The balance of plant cost category comprises the structures, land, service facilities, power conditioning, instrumentation and controls, and spare part costs. The indirect/contingency category consists of the indirect construction and the contingency costs. The concepts included in the study are (1) molten salt cavity central receiver with salt storage (PFCR/R-C-Salt); (2) molten salt external central receiver with salt storage (PFCR/R-E-Salt); (3) sodium external central receiver with sodium storage (PFCR/RE-Na); (4) sodium external central receiver with salt storage (PFCR/R-E-Na/Salt); (5) water/steam external central receiver with oil/rock storage (PFCR/R-E-W/S); (6) parabolic dish with stirling engine conversion and lead acid battery storage (PFDR/SLAB); (7) parabolic dish with stirling engine conversion and redox advanced battery storage (PFDR/S-RAB); and (8) parabolic trough with oil/rock storage (LFDR/R-HT-45). Key annual efficiency and economic results of the study are highlighted in tabular format for plant sizes and capacity factor that resulted in the lowest LEC over the analysis range.

48 CFR 836.602-4 - Selection authority.

Code of Federal Regulations, 2011 CFR

2011-10-01

... CATEGORIES OF CONTRACTING CONSTRUCTION AND ARCHITECT-ENGINEER CONTRACTS Architect-Engineer Services 836.602-4 Selection authority. The Director, Office of Construction and Facilities Management (for Central Office contracts), the Director, Office of Construction Management (for National Cemetery Administration contracts...

48 CFR 836.602-4 - Selection authority.

Code of Federal Regulations, 2012 CFR

2012-10-01

... CATEGORIES OF CONTRACTING CONSTRUCTION AND ARCHITECT-ENGINEER CONTRACTS Architect-Engineer Services 836.602-4 Selection authority. The Director, Office of Construction and Facilities Management (for Central Office contracts), the Director, Office of Construction Management (for National Cemetery Administration contracts...

48 CFR 836.602-4 - Selection authority.

Code of Federal Regulations, 2014 CFR

2014-10-01

... CATEGORIES OF CONTRACTING CONSTRUCTION AND ARCHITECT-ENGINEER CONTRACTS Architect-Engineer Services 836.602-4 Selection authority. The Director, Office of Construction and Facilities Management (for Central Office contracts), the Director, Office of Construction Management (for National Cemetery Administration contracts...

48 CFR 836.602-4 - Selection authority.

Code of Federal Regulations, 2013 CFR

2013-10-01

... CATEGORIES OF CONTRACTING CONSTRUCTION AND ARCHITECT-ENGINEER CONTRACTS Architect-Engineer Services 836.602-4 Selection authority. The Director, Office of Construction and Facilities Management (for Central Office contracts), the Director, Office of Construction Management (for National Cemetery Administration contracts...

Photographic copy of historic photograph, by Corps of Engineers, U.S. ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Photographic copy of historic photograph, by Corps of Engineers, U.S. Army, November 19, 1943 (original in possession of Corps of Engineers, U.S. Army, Pittsburgh District, Engineering Division files) Unit 6, view of WPA masonry wall and dike upstream from Central Avenue Bridge - Johnstown Local Flood Protection Project, Beginning on Conemaugh River approx 3.8 miles downstream from confluence of Little Conemaugh & Stony Creek Rivers at Johnstown, Johnstown, Cambria County, PA

Unusual Central Engine Activity in the Double Burst GRB 110709B

NASA Technical Reports Server (NTRS)

Zhang, Bin-Bin; Burrows, David N.; Zhang, Bing; Meszaros, Peter; Stratta, Giulia; D'Elia, Valerio; Frederiks, Dmitry; Golenetskii, S.; Cummings, Jay R.; Wang, Xiang-Yu;

Bioengineering approaches to controlled protein delivery.

PubMed

Kobsa, Serge; Saltzman, W Mark

2008-05-01

Proteins are of crucial importance in all biologic organisms, in terms of both structure and function. Their deficits play central roles in many pathologic states, and their potential as powerful therapeutic agents has been widely recognized. Many issues, however, exist in delivery of biologically active proteins to target tissues and organs. Recent advances in biomedical engineering have lead to development of advanced techniques for controlled delivery of peptides and proteins, paving the way for their efficient use in treating human injury and disease. With a particular emphasis on most recent advances, this review discusses currently available techniques for controlled delivery of proteins and considers future research directions.

Engineering and Software Engineering

NASA Astrophysics Data System (ADS)

Jackson, Michael

The phrase ‘software engineering' has many meanings. One central meaning is the reliable development of dependable computer-based systems, especially those for critical applications. This is not a solved problem. Failures in software development have played a large part in many fatalities and in huge economic losses. While some of these failures may be attributable to programming errors in the narrowest sense—a program's failure to satisfy a given formal specification—there is good reason to think that most of them have other roots. These roots are located in the problem of software engineering rather than in the problem of program correctness. The famous 1968 conference was motivated by the belief that software development should be based on “the types of theoretical foundations and practical disciplines that are traditional in the established branches of engineering.” Yet after forty years of currency the phrase ‘software engineering' still denotes no more than a vague and largely unfulfilled aspiration. Two major causes of this disappointment are immediately clear. First, too many areas of software development are inadequately specialised, and consequently have not developed the repertoires of normal designs that are the indispensable basis of reliable engineering success. Second, the relationship between structural design and formal analytical techniques for software has rarely been one of fruitful synergy: too often it has defined a boundary between competing dogmas, at which mutual distrust and incomprehension deprive both sides of advantages that should be within their grasp. This paper discusses these causes and their effects. Whether the common practice of software development will eventually satisfy the broad aspiration of 1968 is hard to predict; but an understanding of past failure is surely a prerequisite of future success.

A GRB and Broad-lined Type Ic Supernova from a Single Central Engine

NASA Astrophysics Data System (ADS)

Barnes, Jennifer; Duffell, Paul C.; Liu, Yuqian; Modjaz, Maryam; Bianco, Federica B.; Kasen, Daniel; MacFadyen, Andrew I.

2018-06-01

Unusually high velocities (≳0.1c) and correspondingly high kinetic energies have been observed in a subset of Type Ic supernovae (so-called “broad-lined Ic” supernovae; SNe Ic-BL), prompting a search for a central engine model capable of generating such energetic explosions. A clue to the explosion mechanism may lie in the fact that all supernovae that accompany long-duration gamma-ray bursts (GRBs) belong to the SN Ic-BL class. Using a combination of two-dimensional relativistic hydrodynamics and radiation transport calculations, we demonstrate that the central engine responsible for long GRBs can also trigger an SN Ic-BL. We find that a reasonable GRB engine injected into a stripped Wolf–Rayet progenitor produces a relativistic jet with energy ∼1051 erg, as well as an SN whose synthetic light curves and spectra are fully consistent with observed SNe Ic-BL during the photospheric phase. As a result of the jet’s asymmetric energy injection, the SN spectra and light curves depend on viewing angle. The impact of viewing angle on the spectrum is particularly pronounced at early times, while the viewing-angle dependence for the light curves (∼10% variation in bolometric luminosity) persists throughout the photospheric phase.

A&M. Jet engine test building (TAN609). Exterior. Equipment inside rollup ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

A&M. Jet engine test building (TAN-609). Exterior. Equipment inside roll-up door is blowdown test facility, part of loft-semiscale program. Note width of central section serving as blast protection for operator on left side. Photographer: Cahoon. Date: July 22, 1965. INEEL negative no. 65-3703 - Idaho National Engineering Laboratory, Test Area North, Scoville, Butte County, ID

Creating metabolic demand as an engineering strategy in Pseudomonas putida - Rhamnolipid synthesis as an example.

PubMed

Tiso, Till; Sabelhaus, Petra; Behrens, Beate; Wittgens, Andreas; Rosenau, Frank; Hayen, Heiko; Blank, Lars Mathias

2016-12-01

Metabolic engineering of microbial cell factories for the production of heterologous secondary metabolites implicitly relies on the intensification of intracellular flux directed toward the product of choice. Apart from reactions following peripheral pathways, enzymes of the central carbon metabolism are usually targeted for the enhancement of precursor supply. In Pseudomonas putida , a Gram-negative soil bacterium, central carbon metabolism, i.e., the reactions required for the synthesis of all 12 biomass precursors, was shown to be regulated at the metabolic level and not at the transcriptional level. The bacterium's central carbon metabolism appears to be driven by demand to react rapidly to ever-changing environmental conditions. In contrast, peripheral pathways that are only required for growth under certain conditions are regulated transcriptionally. In this work, we show that this regulation regime can be exploited for metabolic engineering. We tested this driven-by-demand metabolic engineering strategy using rhamnolipid production as an example. Rhamnolipid synthesis relies on two pathways, i.e., fatty acid de novo synthesis and the rhamnose pathway, providing the required precursors hydroxyalkanoyloxy-alkanoic acid (HAA) and activated (dTDP-)rhamnose, respectively. In contrast to single-pathway molecules, rhamnolipid synthesis causes demand for two central carbon metabolism intermediates, i.e., acetyl-CoA for HAA and glucose-6-phosphate for rhamnose synthesis. Following the above-outlined strategy of driven by demand, a synthetic promoter library was developed to identify the optimal expression of the two essential genes ( rhlAB ) for rhamnolipid synthesis. The best rhamnolipid-synthesizing strain had a yield of 40% rhamnolipids on sugar [Cmol RL /Cmol Glc ], which is approximately 55% of the theoretical yield. The rate of rhamnolipid synthesis of this strain was also high. Compared to an exponentially growing wild type, the rhamnose pathway increased its flux by 300%, whereas the flux through de novo fatty acid synthesis increased by 50%. We show that the central carbon metabolism of P. putida is capable of meeting the metabolic demand generated by engineering transcription in peripheral pathways, thereby enabling a significant rerouting of carbon flux toward the product of interest, in this case, rhamnolipids of industrial interest.

Broad-band emission properties of central engine powered supernova ejecta interacting with a circumstellar medium

NASA Astrophysics Data System (ADS)

Suzuki, Akihiro; Maeda, Keiichi

2018-04-01

We investigate broad-band emission from supernova ejecta powered by a relativistic wind from a central compact object. A recent two-dimensional hydrodynamic simulation studying the dynamical evolution of supernova ejecta with a central energy source has revealed that outermost layers of the ejecta are accelerated to mildly relativistic velocities because of the breakout of a hot bubble driven by the energy injection. The outermost layers decelerate as they sweep a circumstellar medium surrounding the ejecta, leading to the formation of the forward and reverse shocks propagating in the circumstellar medium and the ejecta. While the ejecta continue to release the internal energy as thermal emission from the photosphere, the energy dissipation at the forward and reverse shock fronts gives rise to non-thermal emission. We calculate light curves and spectral energy distributions of thermal and non-thermal emission from central engine powered supernova ejecta embedded in a steady stellar wind with typical mass loss rates for massive stars. The light curves are compared with currently available radio and X-ray observations of hydrogen-poor superluminous supernovae, as well as the two well-studied broad-lined Ic supernovae, 1998bw and 2009bb, which exhibit bright radio emission indicating central engine activities. We point out that upper limits on radio luminosities of nearby superluminous supernovae may indicate the injected energy is mainly converted to thermal radiation rather than creating mildly relativistic flows owing to photon diffusion time scales comparable to the injection time scale.

Solving the 56Ni Puzzle of Magnetar-powered Broad-lined Type IC Supernovae

NASA Astrophysics Data System (ADS)

Wang, Ling-Jun; Han, Yan-Hui; Xu, Dong; Wang, Shan-Qin; Dai, Zi-Gao; Wu, Xue-Feng; Wei, Jian-Yan

2016-11-01

Broad-lined Type Ic supernovae (SNe Ic-BL) are of great importance because their association with long-duration gamma-ray bursts (LGRBs) holds the key to deciphering the central engine of LGRBs, which refrains from being unveiled despite decades of investigation. Among the two popularly hypothesized types of central engine, I.e., black holes and strongly magnetized neutron stars (magnetars), there is mounting evidence that the central engine of GRB-associated SNe (GRB-SNe) is rapidly rotating magnetars. Theoretical analysis also suggests that magnetars could be the central engine of SNe Ic-BL. What puzzled the researchers is the fact that light-curve modeling indicates that as much as 0.2{--}0.5 {M}⊙ of 56Ni was synthesized during the explosion of the SNe Ic-BL, which is unfortunately in direct conflict with current state-of-the-art understanding of magnetar-powered 56Ni synthesis. Here we propose a dynamic model of magnetar-powered SNe to take into account the acceleration of the ejecta by the magnetar, as well as the thermalization of the injected energy. Assuming that the SN kinetic energy comes exclusively from the magnetar acceleration, we find that although a major fraction of the rotational energy of the magnetar is to accelerate the SN ejecta, a tiny fraction of this energy deposited as thermal energy of the ejecta is enough to reduce the needed 56Ni to 0.06 M ⊙ for both SN 1997ef and SN 2007ru. We therefore suggest that magnetars could power SNe Ic-BL in aspects both of energetics and of 56Ni synthesis.

Late-time X-rays to map the Zoo of Engine-driven Stellar Explosions

NASA Astrophysics Data System (ADS)

Margutti, Raffaella

2017-09-01

We propose a continuation of our effort to monitor nearby long GRBs (z <=0.3) with Chandra. Our synergistic multi-wavelength program (radio, optical, Swift and proposed Chandra) is designed to extract the true energy of these explosions and to reveal the activity of their central engines. This effort allows us to: (i) investigate whether sub-energetic GRBs share the same explosion mechanisms and central engines as ordinary GRBs; (ii) investigate what essential physical property enables only a small fraction of supernovae to harbor a relativistic outflow; (iii) understand if jet-driven explosions are common in all SNe. These objectives are only possible by expanding the current small sample of well-observed local GRBs and by drawing comparisons with cosmological GRBs and common SNe.

Integrated analysis of engine structures

NASA Technical Reports Server (NTRS)

Chamis, C. C.

1981-01-01

The need for light, durable, fuel efficient, cost effective aircraft requires the development of engine structures which are flexible, made from advaced materials (including composites), resist higher temperatures, maintain tighter clearances and have lower maintenance costs. The formal quantification of any or several of these requires integrated computer programs (multilevel and/or interdisciplinary analysis programs interconnected) for engine structural analysis/design. Several integrated analysis computer prorams are under development at Lewis Reseach Center. These programs include: (1) COBSTRAN-Composite Blade Structural Analysis, (2) CODSTRAN-Composite Durability Structural Analysis, (3) CISTRAN-Composite Impact Structural Analysis, (4) STAEBL-StruTailoring of Engine Blades, and (5) ESMOSS-Engine Structures Modeling Software System. Three other related programs, developed under Lewis sponsorship, are described.

46 CFR 11.505 - Engineer officer structure.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 1 2010-10-01 2010-10-01 false Engineer officer structure. 11.505 Section 11.505 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY MERCHANT MARINE OFFICERS AND SEAMEN REQUIREMENTS FOR OFFICER ENDORSEMENTS Professional Requirements for Engineer Officer § 11.505 Engineer officer structure...

46 CFR 11.505 - Engineer officer structure.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 1 2013-10-01 2013-10-01 false Engineer officer structure. 11.505 Section 11.505 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY MERCHANT MARINE OFFICERS AND SEAMEN REQUIREMENTS FOR OFFICER ENDORSEMENTS Professional Requirements for Engineer Officer § 11.505 Engineer officer structure...

46 CFR 11.505 - Engineer officer structure.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 1 2011-10-01 2011-10-01 false Engineer officer structure. 11.505 Section 11.505 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY MERCHANT MARINE OFFICERS AND SEAMEN REQUIREMENTS FOR OFFICER ENDORSEMENTS Professional Requirements for Engineer Officer § 11.505 Engineer officer structure...

46 CFR 11.505 - Engineer officer structure.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 1 2012-10-01 2012-10-01 false Engineer officer structure. 11.505 Section 11.505 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY MERCHANT MARINE OFFICERS AND SEAMEN REQUIREMENTS FOR OFFICER ENDORSEMENTS Professional Requirements for Engineer Officer § 11.505 Engineer officer structure...

The Core-Collapse Supernova-Black Hole Connection

NASA Astrophysics Data System (ADS)

O'Connor, Evan

The death of a massive star is typically associated with a bright optical transient known as a core-collapse supernova. However, there is growing evidence that not all massive stars end their lives with a brillant optical display, but rather in a whimper. These failed supernovae, or unnovae, result from the central engine failing to turn the initial implosion of the iron core into an explosion that launches the supernova shock wave, unbinds the majority of the star, and creates the supernova as we know it. In these unnovae, the failure of the central engine is soon followed by the collapse of the would-be neutron star into a stellar mass black hole. Instead of the bright optical display following successful supernovae, little to no optical emission is expected from typical failed supernovae as most of the material quietly accretes onto the black hole. This makes the hunt for failed supernovae difficult. In this chapter for the Handbook of Supernovae, I present the growing observational evidence for failed supernovae and discuss the current theoretical understanding of how and in what stars the supernova central engine fails.

The Effects of Different Factors on the Behavior of Neural Stem Cells

PubMed Central

Huang, Lixiang

2017-01-01

The repair of central nervous system (CNS) injury has been a worldwide problem in the biomedical field. How to reduce the damage to the CNS and promote the reconstruction of the damaged nervous system structure and function recovery has always been the concern of nerve tissue engineering. Multiple differentiation potentials of neural stem cell (NSC) determine the application value for the repair of the CNS injury. Thus, how to regulate the behavior of NSCs becomes the key to treating the CNS injury. So far, a large number of researchers have devoted themselves to searching for a better way to regulate the behavior of NSCs. This paper summarizes the effects of different factors on the behavior of NSCs in the past 10 years, especially on the proliferation and differentiation of NSCs. The final purpose of this review is to provide a more detailed theoretical basis for the clinical repair of the CNS injury by nerve tissue engineering. PMID:29358957

Unusual multiscale mechanics of biomimetic nanoparticle hydrogels

DOE PAGES

Zhou, Yunlong; Damasceno, Pablo F.; Somashekar, Bagganahalli S.; ...

2018-01-12

Viscoelastic properties are central for gels and other materials. Simultaneously, high storage and loss moduli are difficult to attain due to their contrarian requirements to chemical structure. Biomimetic inorganic nanoparticles offer a promising toolbox for multiscale engineering of gel mechanics, but a conceptual framework for their molecular, nanoscale, mesoscale, and microscale engineering as viscoelastic materials is absent. Here we show nanoparticle gels with simultaneously high storage and loss moduli from CdTe nanoparticles. Viscoelastic figure of merit reaches 1.83 MPa exceeding that of comparable gels by 100–1000 times for glutathione-stabilized nanoparticles. The gels made from the smallest nanoparticles display the highestmore » stiffness, which was attributed to the drastic change of GSH configurations when nanoparticles decrease in size. A computational model accounting for the difference in nanoparticle interactions for variable GSH configurations describes the unusual trends of nanoparticle gel viscoelasticity. These observations are generalizable to other NP gels interconnected by supramolecular interactions and lead to materials with high-load bearing abilities and energy dissipation needed for multiple technologies.« less

Unusual multiscale mechanics of biomimetic nanoparticle hydrogels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhou, Yunlong; Damasceno, Pablo F.; Somashekar, Bagganahalli S.

Viscoelastic properties are central for gels and other materials. Simultaneously, high storage and loss moduli are difficult to attain due to their contrarian requirements to chemical structure. Biomimetic inorganic nanoparticles offer a promising toolbox for multiscale engineering of gel mechanics, but a conceptual framework for their molecular, nanoscale, mesoscale, and microscale engineering as viscoelastic materials is absent. Here we show nanoparticle gels with simultaneously high storage and loss moduli from CdTe nanoparticles. Viscoelastic figure of merit reaches 1.83 MPa exceeding that of comparable gels by 100–1000 times for glutathione-stabilized nanoparticles. The gels made from the smallest nanoparticles display the highestmore » stiffness, which was attributed to the drastic change of GSH configurations when nanoparticles decrease in size. A computational model accounting for the difference in nanoparticle interactions for variable GSH configurations describes the unusual trends of nanoparticle gel viscoelasticity. These observations are generalizable to other NP gels interconnected by supramolecular interactions and lead to materials with high-load bearing abilities and energy dissipation needed for multiple technologies.« less

ENGINEERING-GEOLOGY SITE APPRAISAL OF THE FEDERAL CAPITAL TERRITORY, NIGERIA.

USGS Publications Warehouse

Ege, J.R.; Griffitts, W.R.; Overstreet, W.C.

1985-01-01

The 7,700-km**2-area Federal Capital Territory, Nigeria, is underlain by crystalline igneous and metamorphic rocks of Precambrian age. Laterite caps many hills of Cretaceous rock, some hills of Precambrian rock, and crops out near stream banks in the east and northeast. The most conspicuous structural features are a broad 'J'-shaped fold traversing the eastern and central part of the Territory and a north-trending shear zone along the eastern boundary. The soils of the Territory are lateritic and belong to the SW-SP-SM (Unified Soil Classification System) groups covering Precambrian migmatites, gneisses and granites and the SC group covering Cretaceous sediments and Precambrian mica-rich schists. The engineering characteristics of the rocks are medium- to high-strength massive and gneissic rock, low-to medium-strength bedded rock, and low-strength foliated and sheared rock. An area of at least 800 km**2 is free from apparent geological hazards and should be suitable for construction of a capital city, its environs and supporting facilities.

Stability Analysis of Distributed Engine Control Systems Under Communication Packet Drop (Postprint)

DTIC Science & Technology

2008-07-01

use, modify, reproduce, release, perform, display, or disclose the work. 14. ABSTRACT Currently, Full Authority Digital Engine Control ( FADEC ...based on a centralized architecture framework is being widely used for gas turbine engine control. However, current FADEC is not able to meet the...system (DEC). FADEC based on Distributed Control Systems (DCS) offers modularity, improved control systems prognostics and fault tolerance along with

Recorded motions of the 6 April 2009 Mw 6.3 L'Aquila, Italy, earthquake and implications for building structural damage: Overview

USGS Publications Warehouse

Celebi, M.; Bazzurro, P.; Chiaraluce, L.; Clemente, P.; Decanini, L.; Desortis, A.; Ellsworth, W.; Gorini, A.; Kalkan, E.; Marcucci, S.; Milana, G.; Mollaioli, F.; Olivieri, M.; Paolucci, R.; Rinaldis, D.; Rovelli, A.; Sabetta, F.; Stephens, C.

2010-01-01

The normal-faulting earthquake of 6 April 2009 in the Abruzzo Region of central Italy caused heavy losses of life and substantial damage to centuriesold buildings of significant cultural importance and to modern reinforcedconcrete- framed buildings with hollow masonry infill walls. Although structural deficiencies were significant and widespread, the study of the characteristics of strong motion data from the heavily affected area indicated that the short duration of strong shaking may have spared many more damaged buildings from collapsing. It is recognized that, with this caveat of shortduration shaking, the infill walls may have played a very important role in preventing further deterioration or collapse of many buildings. It is concluded that better new or retrofit construction practices that include reinforcedconcrete shear walls may prove helpful in reducing risks in such seismic areas of Italy, other Mediterranean countries, and even in United States, where there are large inventories of deficient structures. ?? 2010, Earthquake Engineering Research Institute.

Human Body Interfacing.

ERIC Educational Resources Information Center

Fryda, Lawrence J.; Harrington, Robert; Szumal, Clint

Electronics Engineering Technology majors in the Industrial and Engineering Technology department at Central Michigan University have developed many real-world projects that represent the type of problem-solving projects encouraged by industry. Two projects that can be used by other educators as freestanding projects or as the core for further…

Engineering the Big Chill: The story of JLab’s Central Helium Liquefier

DOE Office of Scientific and Technical Information (OSTI.GOV)

Westfall, Catherine

This article tells the story of the Central Helium Liquefier (CHL) at the Thomas Jefferson National Accelerator Facility (JLab), one of the US National Laboratories. JLab’s successful superconducting radio frequency accelerator was only possible because a group of JLab engineers successfully tackled a complex of difficulties to build a cryogenic system that included the CHL, a task that required advancing the frontier of cryogenic technology. Ultimately, these cryogenic advances were applied far beyond JLab to the benefit of cutting-edge programs at other US national laboratories (Oak Ridge, Brookhaven, and the Facility for Rare Isotope Beams at MSU) as well asmore » NASA. In addition, this innovation story dramatizes the sort of engineer-driven technological problem solving that allows the successful launch and operation of experimental projects. Along the way, the CHL story also provides an important addition to our understanding of the role played by engineers and industry in creating knowledge at physics laboratories.« less

Engineering the Big Chill: The story of JLab’s Central Helium Liquefier

DOE PAGES

Westfall, Catherine

2014-03-29

This article tells the story of the Central Helium Liquefier (CHL) at the Thomas Jefferson National Accelerator Facility (JLab), one of the US National Laboratories. JLab’s successful superconducting radio frequency accelerator was only possible because a group of JLab engineers successfully tackled a complex of difficulties to build a cryogenic system that included the CHL, a task that required advancing the frontier of cryogenic technology. Ultimately, these cryogenic advances were applied far beyond JLab to the benefit of cutting-edge programs at other US national laboratories (Oak Ridge, Brookhaven, and the Facility for Rare Isotope Beams at MSU) as well asmore » NASA. In addition, this innovation story dramatizes the sort of engineer-driven technological problem solving that allows the successful launch and operation of experimental projects. Along the way, the CHL story also provides an important addition to our understanding of the role played by engineers and industry in creating knowledge at physics laboratories.« less

Bright x-ray flares in gamma-ray burst afterglows.

PubMed

Burrows, D N; Romano, P; Falcone, A; Kobayashi, S; Zhang, B; Moretti, A; O'brien, P T; Goad, M R; Campana, S; Page, K L; Angelini, L; Barthelmy, S; Beardmore, A P; Capalbi, M; Chincarini, G; Cummings, J; Cusumano, G; Fox, D; Giommi, P; Hill, J E; Kennea, J A; Krimm, H; Mangano, V; Marshall, F; Mészáros, P; Morris, D C; Nousek, J A; Osborne, J P; Pagani, C; Perri, M; Tagliaferri, G; Wells, A A; Woosley, S; Gehrels, N

2005-09-16

Gamma-ray burst (GRB) afterglows have provided important clues to the nature of these massive explosive events, providing direct information on the nearby environment and indirect information on the central engine that powers the burst. We report the discovery of two bright x-ray flares in GRB afterglows, including a giant flare comparable in total energy to the burst itself, each peaking minutes after the burst. These strong, rapid x-ray flares imply that the central engines of the bursts have long periods of activity, with strong internal shocks continuing for hundreds of seconds after the gamma-ray emission has ended.

Supporting productive thinking: The semiotic context for Cognitive Systems Engineering (CSE).

PubMed

Flach, John

2017-03-01

The central thesis of this paper is that Rasmussen framed his approach to Cognitive Systems Engineering from the perspective of a Triadic Semiotic Model. This frame became the context for integrating multiple intellectual threads including Control Theory, Information Theory, Ecological Psychology, and Gestalt Psychology into a coherent theoretical framework. The case is made that the triadic semiotic framework is essential for a complete appreciation of the constructs that were central to Rasmussen's approach: Abstraction Hierarchy, Skill-Rules-Knowledge Model, Ecological Interface Design, and Proactive Risk Management. Copyright © 2015 Elsevier Ltd. All rights reserved.

Heat Transfer Principles in Thermal Calculation of Structures in Fire

PubMed Central

Zhang, Chao; Usmani, Asif

2016-01-01

Structural fire engineering (SFE) is a relatively new interdisciplinary subject, which requires a comprehensive knowledge of heat transfer, fire dynamics and structural analysis. It is predominantly the community of structural engineers who currently carry out most of the structural fire engineering research and design work. The structural engineering curriculum in universities and colleges do not usually include courses in heat transfer and fire dynamics. In some institutions of higher education, there are graduate courses for fire resistant design which focus on the design approaches in codes. As a result, structural engineers who are responsible for structural fire safety and are competent to do their jobs by following the rules specified in prescriptive codes may find it difficult to move toward performance-based fire safety design which requires a deep understanding of both fire and heat. Fire safety engineers, on the other hand, are usually focused on fire development and smoke control, and may not be familiar with the heat transfer principles used in structural fire analysis, or structural failure analysis. This paper discusses the fundamental heat transfer principles in thermal calculation of structures in fire, which might serve as an educational guide for students, engineers and researchers. Insights on problems which are commonly ignored in performance based fire safety design are also presented. PMID:26783379

14 CFR 25.361 - Engine torque.

Code of Federal Regulations, 2010 CFR

2010-01-01

... engine mount and its supporting structure must be designed for the effects of— (1) A limit engine torque.... (b) For turbine engine installations, the engine mounts and supporting structure must be designed to... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Engine torque. 25.361 Section 25.361...

14 CFR 25.361 - Engine torque.

Code of Federal Regulations, 2012 CFR

2012-01-01

... engine mount and its supporting structure must be designed for the effects of— (1) A limit engine torque.... (b) For turbine engine installations, the engine mounts and supporting structure must be designed to... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Engine torque. 25.361 Section 25.361...

14 CFR 25.361 - Engine torque.

Code of Federal Regulations, 2014 CFR

2014-01-01

... engine mount and its supporting structure must be designed for the effects of— (1) A limit engine torque.... (b) For turbine engine installations, the engine mounts and supporting structure must be designed to... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Engine torque. 25.361 Section 25.361...

14 CFR 25.361 - Engine torque.

Code of Federal Regulations, 2011 CFR

2011-01-01

... engine mount and its supporting structure must be designed for the effects of— (1) A limit engine torque.... (b) For turbine engine installations, the engine mounts and supporting structure must be designed to... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Engine torque. 25.361 Section 25.361...

14 CFR 25.361 - Engine torque.

Code of Federal Regulations, 2013 CFR

2013-01-01

... engine mount and its supporting structure must be designed for the effects of— (1) A limit engine torque.... (b) For turbine engine installations, the engine mounts and supporting structure must be designed to... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Engine torque. 25.361 Section 25.361...

Structural Engineering: Overview

NASA Technical Reports Server (NTRS)

Castro, Edgar

2011-01-01

This slide presentation presents the work of the Structural Engineering Division of the Engineering Directorate. The work includes: providing technical expertise and leadership for the development, evaluation, and operation of structural, mechanical, and thermal spaceflight systems.

75 FR 17703 - Combined Notice of Filings # 1

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-07

...: Southwest Power Pool, Inc submits Substitute Sixth Revised Sheet 14 et al to its FERC Electric Tariff, Fifth...: Central Maine Power Company. Description: Central Maine Power Company submits Engineering and Procurement.... Docket Numbers: ER10-911-001. Applicants: Wisconsin Electric Power Company. Description: Wisconsin...

Inspiration from nature: dynamic modelling of the musculoskeletal structure of the seahorse tail.

PubMed

Praet, Tomas; Adriaens, Dominique; Van Cauter, Sofie; Masschaele, Bert; De Beule, Matthieu; Verhegghe, Benedict

2012-10-01

Technological advances are often inspired by nature, considering that engineering is frequently faced by the same challenges as organisms in nature. One such interesting challenge is creating a structure that is at the same time stiff in a certain direction, yet flexible in another. The seahorse tail combines both radial stiffness and bending flexibility in a particularly elegant way: even though the tail is covered in a protective armour, it still shows sufficient flexibility to fully function as a prehensile organ. We therefore study the complex mechanics and dynamics of the musculoskeletal system of the seahorse tail from an engineering point of view. The seahorse tail derives its combination of flexibility and resilience from a chain of articulating skeletal segments. A versatile dynamic model of those segments was constructed, on the basis of automatic recognition of joint positions and muscle attachments. Both muscle structures that are thought to be responsible for ventral and ventral-lateral tail bending, namely the median ventral muscles and the hypaxial myomere muscles, were included in the model. Simulations on the model consist mainly of dynamic multi-body simulations. The results show that the sequential structure of uniformly shaped bony segments can remain flexible because of gliding joints that connect the corners of the segments. Radial stiffness on the other hand is obtained through the support that the central vertebra provides to the tail plating. Such insights could help in designing biomedical instruments that specifically require both high bending flexibility and radial stiffness (e.g. flexible stents and steerable catheters). Copyright © 2012 John Wiley & Sons, Ltd.

Towards River Rehabilitation as AN Integrated Approach to Flood Management in Asian Cities

NASA Astrophysics Data System (ADS)

Higgitt, David L.

Flood management in Asian cities has conventionally been approached through structural intervention where floods are regarded as a threat requiring control through engineering infrastructure. Such a command and control paradigm represents a marked transition from the way that monsoon flood regimes have been traditionally perceived across Asia. Rapid urbanization and climate change has imposed increasingly difficult flood management challenges as an extension of impermeable surfaces generates rapid runoff and flash flooding, while cities expand into flood-prone areas. Property and communities are placed at enhanced risk. Urbanization reallocates risk as channel and floodplain modification influences flood regimes, while demands for flood protection at certain locations can redistribute risk to other areas. An increasing concern about flood hazard across Asian cities questions whether conventional solutions reliant on structural intervention are sustainable. Such questioning is mirrored by an alternative paradigm of rehabilitation in integrated river basin management — a recognition that restoring and sustaining functional river ecosystems with high biodiversity is one of the greatest challenges facing society. Rehabilitation initiatives demand a new approach to river basin management which encourage interdisciplinary activity, particularly between engineers, hydrologists, geomorphologists and ecologists. The paper sets out some preliminary ideas from a research project investigating the potential for river rehabilitation as a central tenet of flood management, with a particular focus on Asian cities.

Real-time monitoring and fault locating using amplified spontaneous emission noise reflection for tree-structured Ethernet passive optical networks

NASA Astrophysics Data System (ADS)

Naim, Nani Fadzlina; Ab-Rahman, Mohammad Syuhaimi; Kamaruddin, Nur Hasiba; Bakar, Ahmad Ashrif A.

2013-09-01

Nowadays, optical networks are becoming dense while detecting faulty branches in the tree-structured networks has become problematic. Conventional methods are inconvenient as they require an engineer to visit the failure site to check the optical fiber using an optical time-domain reflectometer. An innovative monitoring technique for tree-structured network topology in Ethernet passive optical networks (EPONs) by using the erbium-doped fiber amplifier to amplify the traffic signal is demonstrated, and in the meantime, a residual amplified spontaneous emission spectrum is used as the input signal to monitor the optical cable from the central office. Fiber Bragg gratings with distinct center wavelengths are employed to reflect the monitoring signals. Faulty branches of the tree-structured EPONs can be identified using a simple and low-cost receiver. We will show that this technique is capable of providing monitoring range up to 32 optical network units using a power meter with a sensitivity of -65 dBm while maintaining the bit error rate of 10-13.

Elastic critical moment for bisymmetric steel profiles and its sensitivity by the finite difference method

NASA Astrophysics Data System (ADS)

Kamiński, M.; Supeł, Ł.

2016-02-01

It is widely known that lateral-torsional buckling of a member under bending and warping restraints of its cross-sections in the steel structures are crucial for estimation of their safety and durability. Although engineering codes for steel and aluminum structures support the designer with the additional analytical expressions depending even on the boundary conditions and internal forces diagrams, one may apply alternatively the traditional Finite Element or Finite Difference Methods (FEM, FDM) to determine the so-called critical moment representing this phenomenon. The principal purpose of this work is to compare three different ways of determination of critical moment, also in the context of structural sensitivity analysis with respect to the structural element length. Sensitivity gradients are determined by the use of both analytical and the central finite difference scheme here and contrasted also for analytical, FEM as well as FDM approaches. Computational study is provided for the entire family of the steel I- and H - beams available for the practitioners in this area, and is a basis for further stochastic reliability analysis as well as durability prediction including possible corrosion progress.

Hierarchical Velocity Structure in the Core of Abell 2597

NASA Technical Reports Server (NTRS)

Still, Martin; Mushotzky, Richard

2004-01-01

We present XMM-Newton RGS and EPIC data of the putative cooling flow cluster Abell 2597. Velocities of the low-ionization emission lines in the spectrum are blue shifted with respect to the high-ionization lines by 1320 (sup +660) (sub -210) kilometers per second, which is consistent with the difference in the two peaks of the galaxy velocity distribution and may be the signature of bulk turbulence, infall, rotation or damped oscillation in the cluster. A hierarchical velocity structure such as this could be the direct result of galaxy mergers in the cluster core, or the injection of power into the cluster gas from a central engine. The uniform X-ray morphology of the cluster, the absence of fine scale temperature structure and the random distribution of the the galaxy positions, independent of velocity, suggests that our line of sight is close to the direction of motion. These results have strong implications for cooling flow models of the cluster Abell 2597. They give impetus to those models which account for the observed temperature structure of some clusters using mergers instead of cooling flows.

Engine Lubricant

NASA Technical Reports Server (NTRS)

1993-01-01

PS 212, a plasma-sprayed coating developed by NASA, is used to coat valves in a new rotorcam engine. The coating eliminates the need for a liquid lubricant in the rotorcam, which has no crankshaft, flywheel, distributor or water pump. Developed by Murray United Development Corporation, it is a rotary engine only 10 inches long with four cylinders radiating outward from a central axle. Company officials say the engine will be lighter, more compact and cheaper to manufacture than current engines and will feature cleaner exhaust emissions. A licensing arrangement with a manufacturer is under negotiation. Primary applications are for automobiles, but the engine may also be used in light aircraft.

14 CFR 25.865 - Fire protection of flight controls, engine mounts, and other flight structure.

Code of Federal Regulations, 2011 CFR

2011-01-01

... Design and Construction Fire Protection § 25.865 Fire protection of flight controls, engine mounts, and other flight structure. Essential flight controls, engine mounts, and other flight structures located in... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Fire protection of flight controls, engine...

14 CFR 25.865 - Fire protection of flight controls, engine mounts, and other flight structure.

Code of Federal Regulations, 2012 CFR

2012-01-01

... Design and Construction Fire Protection § 25.865 Fire protection of flight controls, engine mounts, and other flight structure. Essential flight controls, engine mounts, and other flight structures located in... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Fire protection of flight controls, engine...

14 CFR 23.865 - Fire protection of flight controls, engine mounts, and other flight structure.

Code of Federal Regulations, 2013 CFR

2013-01-01

... controls, engine mounts, and other flight structure. Flight controls, engine mounts, and other flight... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Fire protection of flight controls, engine mounts, and other flight structure. 23.865 Section 23.865 Aeronautics and Space FEDERAL AVIATION...

14 CFR 25.865 - Fire protection of flight controls, engine mounts, and other flight structure.

Code of Federal Regulations, 2010 CFR

2010-01-01

... Design and Construction Fire Protection § 25.865 Fire protection of flight controls, engine mounts, and other flight structure. Essential flight controls, engine mounts, and other flight structures located in... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Fire protection of flight controls, engine...

14 CFR 23.865 - Fire protection of flight controls, engine mounts, and other flight structure.

Code of Federal Regulations, 2012 CFR

2012-01-01

... controls, engine mounts, and other flight structure. Flight controls, engine mounts, and other flight... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Fire protection of flight controls, engine mounts, and other flight structure. 23.865 Section 23.865 Aeronautics and Space FEDERAL AVIATION...

14 CFR 23.865 - Fire protection of flight controls, engine mounts, and other flight structure.

Code of Federal Regulations, 2014 CFR

2014-01-01

... controls, engine mounts, and other flight structure. Flight controls, engine mounts, and other flight... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Fire protection of flight controls, engine mounts, and other flight structure. 23.865 Section 23.865 Aeronautics and Space FEDERAL AVIATION...

14 CFR 23.865 - Fire protection of flight controls, engine mounts, and other flight structure.

Code of Federal Regulations, 2011 CFR

2011-01-01

... controls, engine mounts, and other flight structure. Flight controls, engine mounts, and other flight... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Fire protection of flight controls, engine mounts, and other flight structure. 23.865 Section 23.865 Aeronautics and Space FEDERAL AVIATION...

14 CFR 25.865 - Fire protection of flight controls, engine mounts, and other flight structure.

Code of Federal Regulations, 2014 CFR

2014-01-01

... Design and Construction Fire Protection § 25.865 Fire protection of flight controls, engine mounts, and other flight structure. Essential flight controls, engine mounts, and other flight structures located in... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Fire protection of flight controls, engine...

14 CFR 23.865 - Fire protection of flight controls, engine mounts, and other flight structure.

Code of Federal Regulations, 2010 CFR

2010-01-01

... controls, engine mounts, and other flight structure. Flight controls, engine mounts, and other flight... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Fire protection of flight controls, engine mounts, and other flight structure. 23.865 Section 23.865 Aeronautics and Space FEDERAL AVIATION...

14 CFR 25.865 - Fire protection of flight controls, engine mounts, and other flight structure.

Code of Federal Regulations, 2013 CFR

2013-01-01

... Design and Construction Fire Protection § 25.865 Fire protection of flight controls, engine mounts, and other flight structure. Essential flight controls, engine mounts, and other flight structures located in... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Fire protection of flight controls, engine...

Response Sensitivity of Typical Aircraft Jet Engine Fan Blade-Like Structures to Bird Impacts.

DTIC Science & Technology

1982-05-01

AIRCRAFT ENGINE BU--ETC F/G 21/5 RESPONSE SENSITIVITY OF TYPICAL AIRCRAFT JET ENGINE FAN BLADE -L...SENSITIVITY OF TYPICAL AIRCRAFT JET ENGINE FAN BLADE -LIKE STRUCTURES TO BIRD IMPACTS David P. Bauer Robert S. Bertke University of Dayton Research...COVERED RESPONSE SENSITIVITY OF TYPICAL AIRCRAFT FINAL REPORT JET ENGINE FAN BLADE -LIKE STRUCTURES Oct. 1977 to Jan. 1979 TO BIRD IMPACTS s.

78 FR 36538 - 36(b)(1) Arms Sales Notification

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-18

... training equipment, U.S. Government and contractor engineering, technical and logistics support services... equipment, U.S. Government and contractor engineering, technical and logistics support services, and other... central government and the country's outlying areas. The sale of these C-130Js to Libya will significantly...

ENGINEERING DESIGN CRITERIA FOR SUB-SLAB DEPRESSURIZATION SYSTEMS IN LOW-PERMEABILTY SOLIDS

EPA Science Inventory

The report describes the development of engineering design criteria for the successful design, installation, and operation of sub-slab depressurization systems, based on radon (Rn) mitigation experience on 14 slab-on-grade houses in South Central Florida. The Florida houses are c...

Probing the Active Galactic Nuclei using optical spectroscopy

NASA Astrophysics Data System (ADS)

Vivek, M.

Variability studies offer one of the best tools for understanding the physical conditions present in regions close to the central engine in an AGN. We probed the various properties of AGN through time variability studies of spectral lines in the optical wavelengths using the 2m telescope in IUCAA Girawali observatory. The absorption line variability studies are mainly concentrated in understanding the nature of outflows in quasars. Quasar outflows have a huge impact on the evolution of central supermassive blackholes, their host galaxies and the surrounding intergalactic medium. Studying the variability in these Broad Absorption Lines (BALs) can help us understand the structure, evolution, and basic physical properties of these outflows. We conducted a repeated Low ionization BAL monitoring program with 27 LoBALs (Low Ionization BALs) at z 0.3-2.1 covering timescales from 3.22 to 7.69 years in the quasar rest frame. We see a variety of phenomena, including some BALs that either appeared or disappeared completely and some BALs which do not vary over the observation period. In one case, the excited fine structure lines have changed dramatically. One source shows signatures of radiative acceleration. Here, we present the results from this program. Emission line studies are concentrated in understanding the peculiar characteristics of a dual-AGN source SDSS J092712.64+294344.0.

A new fish scale-derived scaffold for corneal regeneration.

PubMed

Lin, Chien Chen; Ritch, Robert; Lin, Shang Ming; Ni, Mei-Hui; Chang, Yu-Chung; Lu, Yi Lung; Lai, Hong Ji; Lin, Feng-Huei

2010-02-26

The purpose of this study is to develop a novel scaffold, derived from fish scales, as an alternative functional material with sufficient mechanical strength for corneal regenerative applications. Fish scales, which are usually considered as marine wastes, were acellularized, decalcified and fabricated into collagen scaffolds. The microstructure of the acellularized scaffold was imaged by scanning electron microscopy (SEM). The acellularization and decalcification treatments did not affect the naturally 3-dimentional, highly centrally-oriented micropatterned structure of the material. To assess the cytocompatibility of the scaffold with corneal cells, rabbit corneal cells were cultured on the scaffold and examined under SEM and confocal microscopy at different time periods. Rapid cell proliferation and migration on the scaffold were observed under SEM and confocal microscopy. The highly centrally-oriented micropatterned structure of the scaffold was beneficial for efficient nutrient and oxygen supply to the cells cultured in the three-dimensional matrices, and therefore it is useful for high-density cell seeding and spreading. Collectively, we demonstrate the superior cellular conductivity of the newly developed material. We provide evidences for the feasibility of the scaffold as a template for corneal cells growth and migration, and thus the fish scale-derived scaffold can be developed as a promising material for tissue-engineering of cornea.

Influence of a heptad repeat stutter on the pH-dependent conformational behavior of the central coiled-coil from influenza hemagglutinin HA2.

PubMed

Higgins, Chelsea D; Malashkevich, Vladimir N; Almo, Steven C; Lai, Jonathan R

2014-09-01

The coiled-coil is one of the most common protein structural motifs. Amino acid sequences of regions that participate in coiled-coils contain a heptad repeat in which every third then forth residue is occupied by a hydrophobic residue. Here we examine the consequences of a "stutter," a deviation of the idealized heptad repeat that is found in the central coiled-coil of influenza hemagluttinin HA2. Characterization of a peptide containing the native stutter-containing HA2 sequence, as well as several variants in which the stutter was engineered out to restore an idealized heptad repeat pattern, revealed that the stutter is important for allowing coiled-coil formation in the WT HA2 at both neutral and low pH (7.1 and 4.5). By contrast, all variants that contained idealized heptad repeats exhibited marked pH-dependent coiled-coil formation with structures forming much more stably at low pH. A crystal structure of one variant containing an idealized heptad repeat, and comparison to the WT HA2 structure, suggest that the stutter distorts the optimal interhelical core packing arrangement, resulting in unwinding of the coiled-coil superhelix. Interactions between acidic side chains, in particular E69 and E74 (present in all peptides studied), are suggested to play a role in mediating these pH-dependent conformational effects. This conclusion is partially supported by studies on HA2 variant peptides in which these positions were altered to aspartic acid. These results provide new insight into the structural role of the heptad repeat stutter in HA2. © 2014 Wiley Periodicals, Inc.

Suitability of soil bioengineering techniques in Central America: a case study in Nicaragua

NASA Astrophysics Data System (ADS)

Petrone, A.; Preti, F.

2008-02-01

In the last few years "D. I. A. F." (Department of Agriculture and Forestry Engineering of Florence University), has been testing the effectiveness of Soil Bio-Engineering techniques in Central America. The focus of the present study was to find out which native plants were most suited for soil bio-engineering purposes, particularly in the realization of riverbank protection. Furthermore, we have also been aiming at economic efficiency. In the context of sustainable watershed management, these techniques seem to be appropriate, especially in underdeveloped countries. Concerning the plants to be used, we considered three native species, Gliricidia Sepium, Cordia dentata and Jatropha curcas, to be appropriate for this type of work. Economically speaking, the low cost of such interventions in underdeveloped countries, has been shown by the construction of riverbank protection using vegetated crib-walls in Nicaragua.

Beta-propellers: associated functions and their role in human diseases.

PubMed

Pons, Tirso; Gómez, Raú; Chinea, Glay; Valencia, Alfonso

2003-03-01

The beta-propeller fold appears as a very fascinating architecture based on four-stranded antiparallel and twisted beta-sheets, radially arranged around a central tunnel. Similar to the alpha/beta-barrel (TIM-barrel) fold, the beta-propeller has a wide range of different functions, and is gaining substantial attention. Some proteins containing beta-propeller domains have been implicated in the pathogenesis of a variety of diseases such as cancer, Alzheimer, Huntington, arthritis, familial hypercholesterolemia, retinitis pigmentosa, osteogenesis, hypertension, and microbial and viral infections. This article reviews some aspects of 3D structure, amino acids sequence regularities, and biological functions of the proteins containing beta-propeller domains. Major emphasis has been laid on beta-propellers whose functions are associated to human diseases. Recent research efforts reported in the fields of protein engineering, drug design, and protein structure-function relationship studies, concerning the beta-propeller architecture, have also been discussed.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abraitiene, Asta; US Department of Agriculture, Agricultural Research Service, Molecular Plant Pathology Laboratory, Room 214 Building 004 BARC-West, 10300 Baltimore Avenue, Beltsville, MD 20705; Zhao Yan

Transient expression of engineered reporter RNAs encoding an intron-containing green fluorescent protein (GFP) from a Potato virus X-based expression vector previously demonstrated the nuclear targeting capability of the 359 nucleotide Potato spindle tuber viroid (PSTVd) RNA genome. To further delimit the putative nuclear-targeting signal, PSTVd subgenomic fragments were embedded within the intron, and recombinant reporter RNAs were inoculated onto Nicotiana benthamiana plants. Appearance of green fluorescence in leaf tissue inoculated with PSTVd-fragment-containing constructs indicated shuttling of the RNA into the nucleus by fragments as short as 80 nucleotides in length. Plant-to-plant variation in the timing of intron removal and subsequentmore » GFP fluorescence was observed; however, earliest and most abundant GFP expression was obtained with constructs containing the conserved hairpin I palindrome structure and embedded upper central conserved region. Our results suggest that this conserved sequence and/or the stem-loop structure it forms is sufficient for import of PSTVd into the nucleus.« less

The influence of para-seismic vibrations, induced by blasting works, on structures: a Case Study

NASA Astrophysics Data System (ADS)

Andrusikiewicz, Wacław

2018-04-01

Underground mining operations are often associated with the necessity to use explosives. Several hundreds of kilograms of explosives, subdivided into small charges suitable for a specific mining job, are used each time in a blasting operation. In many cases, mining engineers carry out remote central blasting works, which means that all the charges placed at faces are initiated from one control point (usually, a control room in the mine) at the same time. Such coordinated explosions generate para-seismic movements whose consequences can be felt on land surface, with subsequent effects identified in buildings and structures. This paper discusses briefly selected standards applicable to the harmful para-seismic impacts. The author presents the results of the research conducted with the intention to identify harmful effects of the basting works carried out in the "Kłodawa" Salt Mine.

Modified level II streambed-scour analysis for structure I-74-32-4946 crossing Sugar Creek in Montgomery County, Indiana

USGS Publications Warehouse

Miller, R.L.; Robinson, B.A.; Voelker, D.C.

1997-01-01

Level II scour evaluations follow a process in which hydrologic, hydraulic, and sedient-transport data are evaluated to calculate the depth of scour that may result when given discharge is routed through a bridge opening. The results of the modified Levell II analysis for structure I-74-32-4946 on Interstate 74 crossing Sugar Creek in Montgomery County, Indiana are presented. The site is near the town of Crawfordsville in the central part of Montgomery County. Scour depths were computed with the Water Surface PROfile model, version V050196, which incorporates the scour-calculation procedures outlined in Hydraulic Engineering Circular No. 18. Total scour depths at the piers were approximately 13.0 feet for the modeled discharge of 3,000  cubic feet per second and approximately 15.1 feet for the modeled discharge of 41,900 cubic feet per second.

Fusion of uniluminal vascular spheroids: a model for assembly of blood vessels

PubMed Central

Fleming, Paul A.; Argraves, W. Scott; Gentile, Carmine; Neagu, Adrian; Forgacs, Gabor; Drake, Christopher J.

2010-01-01

Here, we evaluated the self-assembly properties of uniluminal vascular spheroids having outer layers of vascular smooth muscle cells and a contiguous inner layer of endothelial cells lining a central lumen. We showed that while pairs of uniluminal vascular spheroids suspended in culture medium fused to form a larger diameter spheroidal structure, spheroids in collagen hydrogels formed elongated structures. These findings highlight the potential use of uniluminal vascular spheroids as modules to engineer blood vessels. We also demonstrate that uniluminal vascular spheroid fusion conforms to models describing the coalescence of liquid drops. Furthermore, the fusion of uniluminal vascular spheroids in vitro closely resembled the in vivo process by which the descending aorta forms from the fusion of the paired dorsal aortae during embryonic development. Together, the findings indicate that tissue liquidity underlies uniluminal vascular spheroid fusion and that in vivo anastomosis of blood vessels may involve a similar mechanism. PMID:19918756

Identification of hybrid node and link communities in complex networks

PubMed Central

He, Dongxiao; Jin, Di; Chen, Zheng; Zhang, Weixiong

2015-01-01

Identifying communities in complex networks is an effective means for analyzing complex systems, with applications in diverse areas such as social science, engineering, biology and medicine. Finding communities of nodes and finding communities of links are two popular schemes for network analysis. These schemes, however, have inherent drawbacks and are inadequate to capture complex organizational structures in real networks. We introduce a new scheme and an effective approach for identifying complex mixture structures of node and link communities, called hybrid node-link communities. A central piece of our approach is a probabilistic model that accommodates node, link and hybrid node-link communities. Our extensive experiments on various real-world networks, including a large protein-protein interaction network and a large network of semantically associated words, illustrated that the scheme for hybrid communities is superior in revealing network characteristics. Moreover, the new approach outperformed the existing methods for finding node or link communities separately. PMID:25728010

Identification of hybrid node and link communities in complex networks.

PubMed

He, Dongxiao; Jin, Di; Chen, Zheng; Zhang, Weixiong

2015-03-02

Identifying communities in complex networks is an effective means for analyzing complex systems, with applications in diverse areas such as social science, engineering, biology and medicine. Finding communities of nodes and finding communities of links are two popular schemes for network analysis. These schemes, however, have inherent drawbacks and are inadequate to capture complex organizational structures in real networks. We introduce a new scheme and an effective approach for identifying complex mixture structures of node and link communities, called hybrid node-link communities. A central piece of our approach is a probabilistic model that accommodates node, link and hybrid node-link communities. Our extensive experiments on various real-world networks, including a large protein-protein interaction network and a large network of semantically associated words, illustrated that the scheme for hybrid communities is superior in revealing network characteristics. Moreover, the new approach outperformed the existing methods for finding node or link communities separately.

Identification of hybrid node and link communities in complex networks

NASA Astrophysics Data System (ADS)

He, Dongxiao; Jin, Di; Chen, Zheng; Zhang, Weixiong

2015-03-01

Identifying communities in complex networks is an effective means for analyzing complex systems, with applications in diverse areas such as social science, engineering, biology and medicine. Finding communities of nodes and finding communities of links are two popular schemes for network analysis. These schemes, however, have inherent drawbacks and are inadequate to capture complex organizational structures in real networks. We introduce a new scheme and an effective approach for identifying complex mixture structures of node and link communities, called hybrid node-link communities. A central piece of our approach is a probabilistic model that accommodates node, link and hybrid node-link communities. Our extensive experiments on various real-world networks, including a large protein-protein interaction network and a large network of semantically associated words, illustrated that the scheme for hybrid communities is superior in revealing network characteristics. Moreover, the new approach outperformed the existing methods for finding node or link communities separately.

Hypobaric Biology: Arabidopsis Gene Expression at Low Atmospheric Pressure1[w

PubMed Central

Paul, Anna-Lisa; Schuerger, Andrew C.; Popp, Michael P.; Richards, Jeffrey T.; Manak, Michael S.; Ferl, Robert J.

2004-01-01

As a step in developing an understanding of plant adaptation to low atmospheric pressures, we have identified genes central to the initial response of Arabidopsis to hypobaria. Exposure of plants to an atmosphere of 10 kPa compared with the sea-level pressure of 101 kPa resulted in the significant differential expression of more than 200 genes between the two treatments. Less than one-half of the genes induced by hypobaria are similarly affected by hypoxia, suggesting that response to hypobaria is unique and is more complex than an adaptation to the reduced partial pressure of oxygen inherent to hypobaric environments. In addition, the suites of genes induced by hypobaria confirm that water movement is a paramount issue at low atmospheric pressures, because many of gene products intersect abscisic acid-related, drought-induced pathways. A motivational constituent of these experiments is the need to address the National Aeronautics and Space Administration's plans to include plants as integral components of advanced life support systems. The design of bioregenerative life support systems seeks to maximize productivity within structures engineered to minimize mass and resource consumption. Currently, there are severe limitations to producing Earth-orbital, lunar, or Martian plant growth facilities that contain Earth-normal atmospheric pressures within light, transparent structures. However, some engineering limitations can be offset by growing plants in reduced atmospheric pressures. Characterization of the hypobaric response can therefore provide data to guide systems engineering development for bioregenerative life support, as well as lead to fundamental insights into aspects of desiccation metabolism and the means by which plants monitor water relations. PMID:14701916

The Unstructured Paramyxovirus Nucleocapsid Protein Tail Domain Modulates Viral Pathogenesis through Regulation of Transcriptase Activity.

PubMed

Thakkar, Vidhi D; Cox, Robert M; Sawatsky, Bevan; da Fontoura Budaszewski, Renata; Sourimant, Julien; Wabbel, Katrin; Makhsous, Negar; Greninger, Alexander L; von Messling, Veronika; Plemper, Richard K

2018-04-15

The paramyxovirus replication machinery comprises the viral large (L) protein and phosphoprotein (P-protein) in addition to the nucleocapsid (N) protein, which encapsidates the single-stranded RNA genome. Common to paramyxovirus N proteins is a C-terminal tail (Ntail). The mechanistic role and relevance for virus replication of the structurally disordered central Ntail section are unknown. Focusing initially on members of the Morbillivirus genus, a series of measles virus (MeV) and canine distemper virus (CDV) N proteins were generated with internal deletions in the unstructured tail section. N proteins with large tail truncations remained bioactive in mono- and polycistronic minireplicon assays and supported efficient replication of recombinant viruses. Bioactivity of Ntail mutants extended to N proteins derived from highly pathogenic Nipah virus. To probe an effect of Ntail truncations on viral pathogenesis, recombinant CDVs were analyzed in a lethal CDV/ferret model of morbillivirus disease. The recombinant viruses displayed different stages of attenuation ranging from ameliorated clinical symptoms to complete survival of infected animals, depending on the molecular nature of the Ntail truncation. Reinfection of surviving animals with pathogenic CDV revealed robust protection against a lethal challenge. The highly attenuated virus was genetically stable after ex vivo passaging and recovery from infected animals. Mechanistically, gradual viral attenuation coincided with stepwise altered viral transcriptase activity in infected cells. These results identify the central Ntail section as a determinant for viral pathogenesis and establish a novel platform to engineer gradual virus attenuation for next-generation paramyxovirus vaccine design. IMPORTANCE Investigating the role of the paramyxovirus N protein tail domain (Ntail) in virus replication, we demonstrated in this study that the structurally disordered central Ntail region is a determinant for viral pathogenesis. We show that internal deletions in this Ntail region of up to 55 amino acids in length are compatible with efficient replication of recombinant viruses in cell culture but result in gradual viral attenuation in a lethal canine distemper virus (CDV)/ferret model. Mechanistically, we demonstrate a role of the intact Ntail region in the regulation of viral transcriptase activity. Recombinant viruses with Ntail truncations induce protective immunity against lethal challenge of ferrets with pathogenic CDV. This identification of the unstructured central Ntail domain as a nonessential paramyxovirus pathogenesis factor establishes a foundation for harnessing Ntail truncations for vaccine engineering against emerging and reemerging members of the paramyxovirus family. Copyright © 2018 American Society for Microbiology.

Distributed Control of Turbofan Engines

DTIC Science & Technology

2009-08-01

performance of the engine. Thus the Full Authority Digital Engine Controller ( FADEC ) still remains the central arbiter of the engine’s dynamic behavior...instance, if the control laws are not distributed the dependence on the FADEC remains high, and system reliability can only be insured through many...if distributed computing is used at the local level and only coordinated by the FADEC . Such an architecture must be studied in the context of noisy

Nonthermal electron-positron pairs and cold matter in the central engines of active galactic nuclei

NASA Technical Reports Server (NTRS)

Zdziarski, Andrzej A.

1992-01-01

The nonthermal e(+/-) pair model of the central engine of active galactic nuclei (AGNs) is discussed. The model assumes that nonthermal e(+/-) pairs are accelerated to highly relativistic energies in a compact region close to the central black hole and in the vicinity of some cold matter. The model has a small number of free parameters and explains a large body of AGN observations from EUV to soft gamma-rays. In particular, the model explains the existence of the UV bump, the soft X-rays excess, the canonical hard X-ray power law, the spectral hardening above about 10 keV, and some of the variability patterns in the soft and hard X-rays. In addition, the model explains the spectral steepening above about 50 keV seen in NGC 4151.

Modeling quasar central engine as a relativistic radiating star

NASA Astrophysics Data System (ADS)

Singh, Ksh. Newton; Pant, Neeraj

2015-01-01

Long ago Hoyle & Fowler attempted to model the central engine of quasars as hot super-massive stars supported by radiation pressure. Whereas the model of Hoyle & Fowler was Newtonian, here we make a toy model of quasar central engines as ultra relativistic ultrahot plasma or as a ball of radiation. Accordingly, we consider general relativistic gravitational collapse including emission of radiation. More specifically, we discuss a new class of radiating fluid ball exact solution in conformally-flat metric which is quasi-static and contracting at negligible rate. The problem is solved by assuming that the metric potential is separable in to radial and time dependent parts. It is found the gravitational mass of the radiating ball M→0 as comoving time t→∞ in conformity of the idea of an "Eternally Collapsing Object" (ECO) which has been claimed to be the true nature of the so-called "Black Holes". In particular, we consider here a quasi-static radiation ball having M≈9.507×107 M ⊙, a radius of ≈2×1014 km, and a luminosity L ∞≈9.1×1046 erg/s. Prima-facie, such an ECO solution is compatible with the central compact object of a quasar having comoving lifetime of ≈107 yr and a distantly observed lifetime ( u) which could be higher by many orders of magnitude.

Design and Engineering Strategies for Synthetic Antimicrobial Peptides

NASA Astrophysics Data System (ADS)

Tossi, Alessandro

Thousands of antimicrobial peptides (AMPs) of prokaryotic, fungal, plant, or animal origin have been identified, and their potential as lead compounds for the design of novel therapeutic agents in the treatment of infection, for stimulating the immune system, or in countering septic shock has been widely recognized. Added to this is their possible use in prophylaxis of infectious diseases for animal or plant protection, for disinfection of surgical instruments or industrial surfaces, and for food preservation among other commercially important applications. Since the early eighties, AMPs have been subject to a vast number of studies aimed at understanding what determines their potency and spectrum of activities against bacterial or fungal pathogens, and at maximizing these while limiting cytotoxic activities toward host cells. Much research has also been directed toward understanding specific mechanisms of action underlying the antimicrobial activity and selectivity, to be able to redesign the peptides for optimal performance. A central theme in the mode of action of many AMPs is their dynamic interaction with biological membranes, which involves various properties of these peptides such as, among others, surface hydrophobicity and polarity, charge, structure, and induced conformational variations. These features are often intimately interconnected so that engineering peptides to independently adjust any one property in particular is not an easy task. However, solid-phase peptide synthesis allows the use of a large repertoire of nonproteinogenic amino acids that can be used in the rational design of peptides to finely tune structural and physicochemical properties and precisely probe structure-function relationships.

Probabilistic structural analysis methods of hot engine structures

NASA Technical Reports Server (NTRS)

Chamis, C. C.; Hopkins, D. A.

1989-01-01

Development of probabilistic structural analysis methods for hot engine structures at Lewis Research Center is presented. Three elements of the research program are: (1) composite load spectra methodology; (2) probabilistic structural analysis methodology; and (3) probabilistic structural analysis application. Recent progress includes: (1) quantification of the effects of uncertainties for several variables on high pressure fuel turbopump (HPFT) turbine blade temperature, pressure, and torque of the space shuttle main engine (SSME); (2) the evaluation of the cumulative distribution function for various structural response variables based on assumed uncertainties in primitive structural variables; and (3) evaluation of the failure probability. Collectively, the results demonstrate that the structural durability of hot engine structural components can be effectively evaluated in a formal probabilistic/reliability framework.

Computational structural mechanics for engine structures

NASA Technical Reports Server (NTRS)

Chamis, C. C.

1989-01-01

The computational structural mechanics (CSM) program at Lewis encompasses: (1) fundamental aspects for formulating and solving structural mechanics problems, and (2) development of integrated software systems to computationally simulate the performance/durability/life of engine structures. It is structured to mainly supplement, complement, and whenever possible replace, costly experimental efforts which are unavoidable during engineering research and development programs. Specific objectives include: investigate unique advantages of parallel and multiprocesses for: reformulating/solving structural mechanics and formulating/solving multidisciplinary mechanics and develop integrated structural system computational simulators for: predicting structural performances, evaluating newly developed methods, and for identifying and prioritizing improved/missing methods needed. Herein the CSM program is summarized with emphasis on the Engine Structures Computational Simulator (ESCS). Typical results obtained using ESCS are described to illustrate its versatility.

14 CFR 25.1182 - Nacelle areas behind firewalls, and engine pod attaching structures containing flammable fluid...

Code of Federal Regulations, 2011 CFR

2011-01-01

... pod attaching structures containing flammable fluid lines. 25.1182 Section 25.1182 Aeronautics and..., and engine pod attaching structures containing flammable fluid lines. (a) Each nacelle area immediately behind the firewall, and each portion of any engine pod attaching structure containing flammable...

14 CFR 25.1182 - Nacelle areas behind firewalls, and engine pod attaching structures containing flammable fluid...

Code of Federal Regulations, 2010 CFR

2010-01-01

... pod attaching structures containing flammable fluid lines. 25.1182 Section 25.1182 Aeronautics and..., and engine pod attaching structures containing flammable fluid lines. (a) Each nacelle area immediately behind the firewall, and each portion of any engine pod attaching structure containing flammable...

40 CFR 86.1542 - Information required.

Code of Federal Regulations, 2011 CFR

2011-07-01

... required: (1) Date and time of day. (2) Test number. (3) Engine intake air or test cell temperature. (4) Barometric pressure. Note: A central laboratory barometer may be used: Provided, That individual test cell... location. (5) Engine intake or test cell and CVS dilution air humidity. (6) Curb idle speed during the test...

40 CFR 86.1542 - Information required.

Code of Federal Regulations, 2012 CFR

2012-07-01

... required: (1) Date and time of day. (2) Test number. (3) Engine intake air or test cell temperature. (4) Barometric pressure. Note: A central laboratory barometer may be used: Provided, That individual test cell... location. (5) Engine intake or test cell and CVS dilution air humidity. (6) Curb idle speed during the test...

48 CFR Appendix A to Part 1219 - Appendix A to Part 1219

Code of Federal Regulations, 2014 CFR

2014-10-01

... Rebuilding of engines, turbines, components and weapons equipment J028/J010 (5) ADP Central Processing Units... Engines, Aircraft; and Components 2840 (10) Radar Equipment (except airborne) and Navigation and Navigational Aids (basic research) 5840/AT31 * The industry categories were derived from Federal Procurement...

48 CFR Appendix A to Part 1219 - Appendix A to Part 1219

Code of Federal Regulations, 2012 CFR

2012-10-01

... Rebuilding of engines, turbines, components and weapons equipment J028/J010 (5) ADP Central Processing Units... Engines, Aircraft; and Components 2840 (10) Radar Equipment (except airborne) and Navigation and Navigational Aids (basic research) 5840/AT31 * The industry categories were derived from Federal Procurement...

48 CFR Appendix A to Part 1219 - Appendix A to Part 1219

Code of Federal Regulations, 2013 CFR

2013-10-01

... Rebuilding of engines, turbines, components and weapons equipment J028/J010 (5) ADP Central Processing Units... Engines, Aircraft; and Components 2840 (10) Radar Equipment (except airborne) and Navigation and Navigational Aids (basic research) 5840/AT31 * The industry categories were derived from Federal Procurement...

48 CFR Appendix A to Part 1219 - Appendix A to Part 1219

Code of Federal Regulations, 2011 CFR

2011-10-01

... Rebuilding of engines, turbines, components and weapons equipment J028/J010 (5) ADP Central Processing Units... Engines, Aircraft; and Components 2840 (10) Radar Equipment (except airborne) and Navigation and Navigational Aids (basic research) 5840/AT31 * The industry categories were derived from Federal Procurement...

Engineering at the Elementary Level

ERIC Educational Resources Information Center

McGrew, Cheryl

2012-01-01

Can engineering technology be taught at the elementary level? Designing and building trebuchets, catapults, solar cars, and mousetrap vehicles in a west central Florida elementary class was considered very unusual in recent years. After a review of current research on failing schools and poor curriculum, the author wondered what her school could…

Biotechnology Process Engineering Center at MIT - Overview

Science.gov Websites

laboratories. Biotechnology-related research in the labs of over 15 faculty members in the Biological 60,000 square feet for biotechnology-related engineering research. This centralization and consolidation wider array of equipment and facilities available in other MIT labs and Centers. Some examples include

A DIRECTORY OF INFORMATION RESOURCES IN THE UNITED STATES. PHYSICAL SCIENCES, BIOLOGICAL SCIENCES, ENGINEERING.

ERIC Educational Resources Information Center

Library of Congress, Washington, DC.

SOURCES OF INFORMATION FOR BIOLOGICAL AND PHYSICAL SCIENCE AND ENGINEERING ARE LISTED. THEY INCLUDE--(1) LIBRARIES, (2) CENTRALIZED INFORMATION CENTERS, (3) PROFESSIONAL SOCIETIES AND OTHER SPECIALIZING ORGANIZATIONS, (4) INDUSTRIAL FIRMS, (5) GOVERNMENTAL AGENCIES OR OFFICES, AND (6) OTHER INFORMATION SOURCES WHICH MAKE SCIENTIFIC AND…

Exploring Agricultural and Biotechnical Engineering through Hands-On Integrated STEM

ERIC Educational Resources Information Center

Preble, Brian C.

2015-01-01

The manipulation of the natural world in the form of plant materials to design, control, and grow desirable agricultural commodities was central to the establishment and advancement of civilization. Modern developments in genetically modified organisms (GMOs or biologically engineered foods) can trace their origins to macro practices developed and…

Ethnographic Evaluation of the MESA Program at a South-Central Phoenix High School.

ERIC Educational Resources Information Center

Jaramillo, James A.

MESA (Mathematics, Engineering, and Science Achievement) is a program designed to increase the number of underrepresented ethnic groups in professions related to mathematics, engineering, and the physical sciences. This paper describes and evaluates the MESA program at Jarama High School, Phoenix (Arizona), using informal interviews and…

Progress in industrial holography in France

NASA Astrophysics Data System (ADS)

Smigielski, Paul

1992-01-01

Industrial applications of holography in France are briefly reviewed. Particular attention is given to nondestructive testing of helicopter blades at Aerospatiale Central Laboratory, the use of holography at Renault for car-engine vibration study, vibration characterization of turbo-jet engine components at SNECMA, and vibration analysis of plates in an industrial hemodynamic tunnel.

16. VIEW OF THE STATIONARY OPERATING ENGINEER CONTROL PANEL INSTALLATION. ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

16. VIEW OF THE STATIONARY OPERATING ENGINEER CONTROL PANEL INSTALLATION. THE PANEL CONTROLS AIR-HANDLING EQUIPMENT AND AIR PRESSURE WITHIN THE BUILDING. (10/6/69) - Rocky Flats Plant, Plutonium Manufacturing Facility, North-central section of Plant, just south of Building 776/777, Golden, Jefferson County, CO

Nanoscale characteristics of triacylglycerol oils: phase separation and binding energies of two-component oils to crystalline nanoplatelets.

PubMed

MacDougall, Colin J; Razul, M Shajahan; Papp-Szabo, Erzsebet; Peyronel, Fernanda; Hanna, Charles B; Marangoni, Alejandro G; Pink, David A

2012-01-01

Fats are elastoplastic materials with a defined yield stress and flow behavior and the plasticity of a fat is central to its functionality. This plasticity is given by a complex tribological interplay between a crystalline phase structured as crystalline nanoplatelets (CNPs) and nanoplatelet aggregates and the liquid oil phase. Oil can be trapped within microscopic pores within the fat crystal network by capillary action, but it is believed that a significant amount of oil can be trapped by adsorption onto crystalline surfaces. This, however, remains to be proven. Further, the structural basis for the solid-liquid interaction remains a mystery. In this work, we demonstrate that the triglyceride liquid structure plays a key role in oil binding and that this binding could potentially be modulated by judicious engineering of liquid triglyceride structure. The enhancement of oil binding is central to many current developments in this area since an improvement in the health characteristics of fat and fat-structured food products entails a reduction in the amount of crystalline triacylglycerols (TAGs) and a relative increase in the amount of liquid TAGs. Excessive amounts of unbound, free oil, will lead to losses in functionality of this important food component. Engineering fats for enhanced oil binding capacity is thus central to the design of more healthy food products. To begin to address this, we modelled the interaction of triacylglycerol oils, triolein (OOO), 1,2-olein elaidin (OOE) and 1,2-elaidin olein (EEO) with a model crystalline nanoplatelet composed of tristearin in an undefined polymorphic form. The surface of the CNP in contact with the oil was assumed to be planar. We considered pure OOO and mixtures of OOO + OOE and OOO + EEO with 80% OOO. The last two cases were taken as approximations to high oleic sunflower oil (HOSO). The intent was to investigate whether phase separation on a nanoscale took place. We defined an "oil binding capacity" parameter, B(Q,Q'), relating a state Q to a reference state Q'. We used atomic scale molecular dynamics in the NVT ensemble and computed averages over 1-5 ns. We found that the probability of the OOE phase separating into a layer on the surface of the CNP compared to being retained randomly in an OOO + OOE mix were approximately equal. However, we found that it was probable that the EEO component of an OOO + EEO mix would phase separate and coat the surface of the CNP. These results suggest a mechanism whereby many-component oils undergo phase separation on a nanoscale so as to create a transition oil region between the surface of the CNP and the bulk major oil component (OOO in the case considered here) so as to create the appropriate oil binding capacity for the use to which it is put.

Protein engineering and the use of molecular modeling and simulation: the case of heterodimeric Fc engineering.

PubMed

Spreter Von Kreudenstein, Thomas; Lario, Paula I; Dixit, Surjit B

2014-01-01

Computational and structure guided methods can make significant contributions to the development of solutions for difficult protein engineering problems, including the optimization of next generation of engineered antibodies. In this paper, we describe a contemporary industrial antibody engineering program, based on hypothesis-driven in silico protein optimization method. The foundational concepts and methods of computational protein engineering are discussed, and an example of a computational modeling and structure-guided protein engineering workflow is provided for the design of best-in-class heterodimeric Fc with high purity and favorable biophysical properties. We present the engineering rationale as well as structural and functional characterization data on these engineered designs. Copyright © 2013 Elsevier Inc. All rights reserved.

Using hub technology to facilitate information system integration in a health-care enterprise.

PubMed

Gendler, S M; Friedman, B A; Henricks, W H

1996-04-01

The deployment and maintenance of multiple point-to-point interfaces between a clinical information system, such as a laboratory information system, and other systems within a healthcare enterprise is expensive and time consuming. Moreover, the demand for such interfaces is increasing as hospitals consolidate and clinical laboratories participate in the development of regional laboratory networks and create host-to-host links with laboratory outreach clients. An interface engine, also called a hub, is an evolving technology that could replace multiple point-to-point interfaces from a laboratory information system with a single interface to the hub, preferably HL7 based. The hub then routes and translates laboratory information to other systems within the enterprise. Changes in application systems in an enterprise where a centralized interface engine has been implemented then amount to thorough analysis, an update of the enterprise's data dictionary, purchase of a single new vendor-supported interface, and table-based parameter changes on the hub. Two other features of an interface engine, support for structured query language and information store-and-forward, will facilitate the development of clinical data repositories and provide flexibility when interacting with other host systems. This article describes the advantages and disadvantages of an interface engine and lists some problems not solved by the technology. Finally, early developmental experience with an interface engine at the University of Michigan Medical Center and the benefits of the project on system integration efforts are described, not the least of which has been the enthusiastic adoption of the HL7 standard for all future interface projects.

Hydrogeologic aspects of the Knippa Gap area in eastern Uvalde and western Medina counties, Texas

USGS Publications Warehouse

Lambert, Rebecca B.; Clark, Allan K.; Pedraza, Diana E.; Morris, Robert R.

2014-01-01

The Edwards aquifer is the primary source of potable water for the San Antonio area in south-central Texas. The Knippa Gap area is a structural low (trough) postulated to channel or restrict flow in the Edwards aquifer in eastern Uvalde and western Medina Counties, Tex. To better understand the function of the Knippa Gap, the U.S. Geological Survey, in cooperation with the U.S. Army Corps of Engineers, developed the first detailed surficial geologic map of the Knippa Gap area with data and information obtained from previous investigations and field observations. A simplified version of the detailed geologic map depicting the hydrologic units, faulting, and structural dips of the Knippa Gap area is provided in this fact sheet. The map shows that groundwater flow in the Edwards aquifer is influenced by the Balcones Fault Zone, a structurally complex area of the aquifer that contains relay ramps that have formed in extensional fault systems and allowed for deformational changes along fault blocks. Faulting in southeast Uvalde and southwest Medina Counties has produced relay-ramp structures that dip downgradient to the structural low (trough) of the Knippa Gap.

Program For Engineering Electrical Connections

NASA Technical Reports Server (NTRS)

Billitti, Joseph W.

1990-01-01

DFACS is interactive multiuser computer-aided-engineering software tool for system-level electrical integration and cabling engineering. Purpose of program to provide engineering community with centralized data base for putting in and gaining access to data on functional definition of system, details of end-circuit pinouts in systems and subsystems, and data on wiring harnesses. Objective, to provide instantaneous single point of interchange of information, thus avoiding error-prone, time-consuming, and costly shuttling of data along multiple paths. Designed to operate on DEC VAX mini or micro computer using Version 5.0/03 of INGRES.

Space shuttle main engine controller

NASA Technical Reports Server (NTRS)

Mattox, R. M.; White, J. B.

1981-01-01

A technical description of the space shuttle main engine controller, which provides engine checkout prior to launch, engine control and monitoring during launch, and engine safety and monitoring in orbit, is presented. Each of the major controller subassemblies, the central processing unit, the computer interface electronics, the input electronics, the output electronics, and the power supplies are described and discussed in detail along with engine and orbiter interfaces and operational requirements. The controller represents a unique application of digital concepts, techniques, and technology in monitoring, managing, and controlling a high performance rocket engine propulsion system. The operational requirements placed on the controller, the extremely harsh operating environment to which it is exposed, and the reliability demanded, result in the most complex and rugged digital system ever designed, fabricated, and flown.

ACCELERATION OF COMPACT RADIO JETS ON SUB-PARSEC SCALES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Sang-Sung; Lobanov, Andrei P.; Krichbaum, Thomas P.

2016-08-01

Jets of compact radio sources are highly relativistic and Doppler boosted, making studies of their intrinsic properties difficult. Observed brightness temperatures can be used to study the intrinsic physical properties of relativistic jets, and constrain models of jet formation in the inner jet region. We aim to observationally test such inner jet models. The very long baseline interferometry (VLBI) cores of compact radio sources are optically thick at a given frequency. The distance of the core from the central engine is inversely proportional to the frequency. Under the equipartition condition between the magnetic field energy and particle energy densities, themore » absolute distance of the VLBI core can be predicted. We compiled the brightness temperatures of VLBI cores at various radio frequencies of 2, 8, 15, and 86 GHz. We derive the brightness temperature on sub-parsec scales in the rest frame of the compact radio sources. We find that the brightness temperature increases with increasing distance from the central engine, indicating that the intrinsic jet speed (the Lorentz factor) increases along the jet. This implies that the jets are accelerated in the (sub-)parsec regions from the central engine.« less

GeneView: a comprehensive semantic search engine for PubMed.

PubMed

Thomas, Philippe; Starlinger, Johannes; Vowinkel, Alexander; Arzt, Sebastian; Leser, Ulf

2012-07-01

Research results are primarily published in scientific literature and curation efforts cannot keep up with the rapid growth of published literature. The plethora of knowledge remains hidden in large text repositories like MEDLINE. Consequently, life scientists have to spend a great amount of time searching for specific information. The enormous ambiguity among most names of biomedical objects such as genes, chemicals and diseases often produces too large and unspecific search results. We present GeneView, a semantic search engine for biomedical knowledge. GeneView is built upon a comprehensively annotated version of PubMed abstracts and openly available PubMed Central full texts. This semi-structured representation of biomedical texts enables a number of features extending classical search engines. For instance, users may search for entities using unique database identifiers or they may rank documents by the number of specific mentions they contain. Annotation is performed by a multitude of state-of-the-art text-mining tools for recognizing mentions from 10 entity classes and for identifying protein-protein interactions. GeneView currently contains annotations for >194 million entities from 10 classes for ∼21 million citations with 271,000 full text bodies. GeneView can be searched at http://bc3.informatik.hu-berlin.de/.

Bioprinted Osteogenic and Vasculogenic Patterns for Engineering 3D Bone Tissue.

PubMed

Byambaa, Batzaya; Annabi, Nasim; Yue, Kan; Trujillo-de Santiago, Grissel; Alvarez, Mario Moisés; Jia, Weitao; Kazemzadeh-Narbat, Mehdi; Shin, Su Ryon; Tamayol, Ali; Khademhosseini, Ali

2017-08-01

Fabricating 3D large-scale bone tissue constructs with functional vasculature has been a particular challenge in engineering tissues suitable for repairing large bone defects. To address this challenge, an extrusion-based direct-writing bioprinting strategy is utilized to fabricate microstructured bone-like tissue constructs containing a perfusable vascular lumen. The bioprinted constructs are used as biomimetic in vitro matrices to co-culture human umbilical vein endothelial cells and bone marrow derived human mesenchymal stem cells in a naturally derived hydrogel. To form the perfusable blood vessel inside the bioprinted construct, a central cylinder with 5% gelatin methacryloyl (GelMA) hydrogel at low methacryloyl substitution (GelMA LOW ) was printed. We also develop cell-laden cylinder elements made of GelMA hydrogel loaded with silicate nanoplatelets to induce osteogenesis, and synthesized hydrogel formulations with chemically conjugated vascular endothelial growth factor to promote vascular spreading. It was found that the engineered construct is able to support cell survival and proliferation during maturation in vitro. Additionally, the whole construct demonstrates high structural stability during the in vitro culture for 21 days. This method enables the local control of physical and chemical microniches and the establishment of gradients in the bioprinted constructs. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Implementation of partnership management model of SMK (Vocational High School) with existing industries in mechanical engineering expertise in Central Java

NASA Astrophysics Data System (ADS)

Sumbodo, Wirawan; Pardjono, Samsudi, Rahadjo, Winarno Dwi

2018-03-01

This study aims to determine the existing conditions of implementation of partnership management model of SMK with the industry on the mechanical engineering expertise in Central Java. The method used is descriptive analysis. The research result shows that the implementation of partnership management model of SMK based on new existing industry produces ready graduates of 62.5% which belongs to low category, although the partnership program of SMK with the industry is done well with the average score of 3.17. As many as 37.5% of SMK graduates of Mechanical Engineering Expertise Program choose to continue their studies or to be an entrepreneur. It is expected that the partnership model of SMK with the industry can be developed into a reference for government policy in developing SMK that is able to produce graduates who are ready to work according to the needs of partner industry.

14 CFR 91.1415 - CAMP: Mechanical reliability reports.

Code of Federal Regulations, 2012 CFR

2012-01-01

... the engine, adjacent structure, equipment, or components; (5) An aircraft component that causes... flight when external damage to the engine or aircraft structure occurs; (8) Engine shutdown during flight... ground; (14) Aircraft structure that requires major repair; (15) Cracks, permanent deformation, or...

14 CFR 91.1415 - CAMP: Mechanical reliability reports.

Code of Federal Regulations, 2014 CFR

2014-01-01

... the engine, adjacent structure, equipment, or components; (5) An aircraft component that causes... flight when external damage to the engine or aircraft structure occurs; (8) Engine shutdown during flight... ground; (14) Aircraft structure that requires major repair; (15) Cracks, permanent deformation, or...

Chapter D. The Loma Prieta, California, Earthquake of October 17, 1989 - Earth Structures and Engineering Characterization of Ground Motion

USGS Publications Warehouse

Holzer, Thomas L.

1998-01-01

This chapter contains two papers that summarize the performance of engineered earth structures, dams and stabilized excavations in soil, and two papers that characterize for engineering purposes the attenuation of ground motion with distance during the Loma Prieta earthquake. Documenting the field performance of engineered structures and confirming empirically based predictions of ground motion are critical for safe and cost effective seismic design of future structures as well as the retrofitting of existing ones.

Ground-water conditions in the central Virgin River basin, Utah

USGS Publications Warehouse

Cordova, R.M.; Sandberg, G.W.; McConkie, Wilson

1972-01-01

Water-rights problems have occurred in the central Virgin River basin and are expected to increase as development of the water resources increases. The Utah State Engineer needs a basic knowledge of ground-water conditions and of the relation of ground water to surface water as a first step to understanding and resolving the problems. Accordingly, the State Engineer requested the U. S. Geological Survey to make a ground-water investigation of the central Virgin River basin as part of the Statewide cooperative agreement with the Utah Department of Natural Resources. The investigation was begun July 1, 1968, and fieldwork was completed in August 1970. Detailed information was obtained for the principal aquifers and for recharge, movement, discharge, storage, utilization, and chemical quality of ground water. A progress report (Cordova, Sandberg, and McConkie, 1970) describes the general findings in the first year of the investigation.

Evaluation of Creative Problem-Solving Abilities in Undergraduate Structural Engineers through Interdisciplinary Problem-Based Learning

ERIC Educational Resources Information Center

McCrum, Daniel Patrick

2017-01-01

For a structural engineer, effective communication and interaction with architects cannot be underestimated as a key skill to success throughout their professional career. Structural engineers and architects have to share a common language and understanding of each other in order to achieve the most desirable architectural and structural designs.…

Status, Vision, and Challenges of an Intelligent Distributed Engine Control Architecture

NASA Technical Reports Server (NTRS)

Behbahani, Alireza; Culley, Dennis; Garg, Sanjay; Millar, Richard; Smith, Bert; Wood, Jim; Mahoney, Tim; Quinn, Ronald; Carpenter, Sheldon; Mailander, Bill;

The Development of a Concept Inventory for Engineering Graphics

ERIC Educational Resources Information Center

Nozaki, Steven Yasuto

2017-01-01

Graphics education has been a central component in the engineering course of study. As technology advances, so have the methods in which graphics are expressed and practiced. Though the of media of graphics education have evolved, the concepts of the field remain relatively consistent. Tools are needed to measure students' comprehension,…

U.S. Engineering Degrees for Improving South Indian Graduate Students' Marriage and Dowry Options

ERIC Educational Resources Information Center

Yakaboski, Tamara; Sheridan, Robyn Stout; Dade, Kristin

2014-01-01

The article examines improved marriage opportunities as an unexplored motivator for pursuing international education via U.S. graduate engineering degrees and stresses the need to centralize gender in analyzing academic mobility and international education. This interdisciplinary qualitative study explores how South Indian men and women's…

University of Maryland MRSEC - Education: Resources

Science.gov Websites

. University of Maryland Materials Research Science and Engineering Center Home About Us Leadership Moments in MSE The Materials Science and Engineering Career Resources Center Materials Research Society Central Super Science Fair Projects: Ideas, Topics, & Experiments All Science Fair Projects Science

Social Cognitive Predictors of Adjustment to Engineering Majors across Gender and Race/Ethnicity

ERIC Educational Resources Information Center

Lent, Robert W.; Miller, Matthew J.; Smith, Paige E.; Watford, Bevlee A.; Lim, Robert H.; Hui, Kayi; Morrison, M. Ashley; Wilkins, Gregory; Williams, Kevin

2013-01-01

We tested a social cognitive model of academic adjustment in a sample of 1377 students enrolled in engineering schools at two predominantly White and two historically Black state universities. The model brought together central elements of social cognitive career theory's (SCCT) segmental models of educational/vocational satisfaction, interest,…

Evaluating Self-Efficacy Expected of Polytechnic Engineering Students as a Measure of Employability

ERIC Educational Resources Information Center

Ojonugwa, Oguche Innocent; Hamzah, Ramlah; Bakar, AB Rahim; Rashid, Abdullah Mat

2015-01-01

In the face of increasing unemployment partly due to decreasing employability skills of Nigeria polytechnic students, many graduates of Nigeria polytechnic have a dwindle self-efficacy. 420 HND 2 polytechnic engineering students in north central states of Nigeria were surveyed. Data were collected using questionnaire consisting of 4 Likert-type…

Prediction of the Thrust Performance and the Flowfield of Liquid Rocket Engines

NASA Technical Reports Server (NTRS)

Wang, T.-S.

1990-01-01

In an effort to improve the current solutions in the design and analysis of liquid propulsive engines, a computational fluid dynamics (CFD) model capable of calculating the reacting flows from the combustion chamber, through the nozzle to the external plume, was developed. The Space Shuttle Main Engine (SSME) fired at sea level, was investigated as a sample case. The CFD model, FDNS, is a pressure based, non-staggered grid, viscous/inviscid, ideal gas/real gas, reactive code. An adaptive upwinding differencing scheme is employed for the spatial discretization. The upwind scheme is based on fourth order central differencing with fourth order damping for smooth regions, and second order central differencing with second order damping for shock capturing. It is equipped with a CHMQGM equilibrium chemistry algorithm and a PARASOL finite rate chemistry algorithm using the point implicit method. The computed flow results and performance compared well with those of other standard codes and engine hot fire test data. In addition, the transient nozzle flowfield calculation was also performed to demonstrate the ability of FDNS in capturing the flow separation during the startup process.

75 FR 2057 - Airworthiness Directives; Airbus Model A340-200 and A340-300 Series Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2010-01-14

... could lead to the loss of the load path for the forward engine mount and damage to other engine mount... loss of the load path for the forward engine mount and damage to other engine mount structures, which... loss of the load path for the forward engine mount and damage to other engine mount structures, which...

* Central Growth Factor Loaded Depots in Bone Tissue Engineering Scaffolds for Enhanced Cell Attraction.

PubMed

Quade, Mandy; Knaack, Sven; Akkineni, Ashwini Rahul; Gabrielyan, Anastasia; Lode, Anja; Rösen-Wolff, Angela; Gelinsky, Michael

2017-08-01

Tissue engineering, the application of stem and progenitor cells in combination with an engineered extracellular matrix, is a promising strategy for bone regeneration. However, its success is limited by the lack of vascularization after implantation. The concept of in situ tissue engineering envisages the recruitment of cells necessary for tissue regeneration from the host environment foregoing ex vivo cell seeding of the scaffold. In this study, we developed a novel scaffold system for enhanced cell attraction, which is based on biomimetic mineralized collagen scaffolds equipped with a central biopolymer depot loaded with chemotactic agents. In humid milieu, as after implantation, the signaling factors are expected to slowly diffuse out of the central depot forming a gradient that stimulates directed cell migration toward the scaffold center. Heparin, hyaluronic acid, and alginate have been shown to be capable of depot formation. By using vascular endothelial growth factor (VEGF) as model factor, it was demonstrated that the release kinetics can be adjusted by varying the depot composition. While alginate and hyaluronic acid are able to reduce the initial burst and prolong the release of VEGF, the addition of heparin led to a much stronger retention that resulted in an almost linear release over 28 days. The biological activity of released VEGF was proven for all variants using an endothelial cell proliferation assay. Furthermore, migration experiments with endothelial cells revealed a relationship between the degree of VEGF retention and migration distance: cells invaded deepest in scaffolds containing a heparin-based depot indicating that the formation of a steep gradient is crucial for cell attraction. In conclusion, this novel in situ tissue engineering approach, specifically designed to recruit and accommodate endogenous cells upon implantation, appeared highly promising to stimulate cell invasion, which in turn would promote vascularization and finally new bone formation.

24 CFR 200.934 - User fee system for the technical suitability of products program.

Code of Federal Regulations, 2012 CFR

2012-04-01

... section establishes fee requirements for the issuance of Structural Engineering Bulletins (SEBs), Mechanical Engineering Bulletins (MEBs), Truss Connector Bulletins (TCBs), Area Letters of Acceptance (ALAs... Department. (i) With respect to Mechanical Engineering Bulletins (MEBs), Structural Engineering Bulletins...

24 CFR 200.934 - User fee system for the technical suitability of products program.

Code of Federal Regulations, 2013 CFR

2013-04-01

... section establishes fee requirements for the issuance of Structural Engineering Bulletins (SEBs), Mechanical Engineering Bulletins (MEBs), Truss Connector Bulletins (TCBs), Area Letters of Acceptance (ALAs... Department. (i) With respect to Mechanical Engineering Bulletins (MEBs), Structural Engineering Bulletins...

24 CFR 200.934 - User fee system for the technical suitability of products program.

Code of Federal Regulations, 2014 CFR

2014-04-01

... section establishes fee requirements for the issuance of Structural Engineering Bulletins (SEBs), Mechanical Engineering Bulletins (MEBs), Truss Connector Bulletins (TCBs), Area Letters of Acceptance (ALAs... Department. (i) With respect to Mechanical Engineering Bulletins (MEBs), Structural Engineering Bulletins...

24 CFR 200.934 - User fee system for the technical suitability of products program.

Code of Federal Regulations, 2011 CFR

2011-04-01

... section establishes fee requirements for the issuance of Structural Engineering Bulletins (SEBs), Mechanical Engineering Bulletins (MEBs), Truss Connector Bulletins (TCBs), Area Letters of Acceptance (ALAs... Department. (i) With respect to Mechanical Engineering Bulletins (MEBs), Structural Engineering Bulletins...

Photo-oxidation of tyrosine in a bio-engineered bacterioferritin 'reaction centre'-a protein model for artificial photosynthesis.

PubMed

Hingorani, Kastoori; Pace, Ron; Whitney, Spencer; Murray, James W; Smith, Paul; Cheah, Mun Hon; Wydrzynski, Tom; Hillier, Warwick

2014-10-01

The photosynthetic reaction centre (RC) is central to the conversion of solar energy into chemical energy and is a model for bio-mimetic engineering approaches to this end. We describe bio-engineering of a Photosystem II (PSII) RC inspired peptide model, building on our earlier studies. A non-photosynthetic haem containing bacterioferritin (BFR) from Escherichia coli that expresses as a homodimer was used as a protein scaffold, incorporating redox-active cofactors mimicking those of PSII. Desirable properties include: a di-nuclear metal binding site which provides ligands for bivalent metals, a hydrophobic pocket at the dimer interface which can bind a photosensitive porphyrin and presence of tyrosine residues proximal to the bound cofactors, which can be utilised as efficient electron-tunnelling intermediates. Light-induced electron transfer from proximal tyrosine residues to the photo-oxidised ZnCe6(•+), in the modified BFR reconstituted with both ZnCe6 and Mn(II), is presented. Three site-specific tyrosine variants (Y25F, Y58F and Y45F) were made to localise the redox-active tyrosine in the engineered system. The results indicate that: presence of bound Mn(II) is necessary to observe tyrosine oxidation in all BFR variants; Y45 the most important tyrosine as an immediate electron donor to the oxidised ZnCe6(•+) and that Y25 and Y58 are both redox-active in this system, but appear to function interchangebaly. High-resolution (2.1Å) crystal structures of the tyrosine variants show that there are no mutation-induced effects on the overall 3-D structure of the protein. Small effects are observed in the Y45F variant. Here, the BFR-RC represents a protein model for artificial photosynthesis. Crown Copyright © 2014. Published by Elsevier B.V. All rights reserved.

75 FR 64303 - Vermont Marble Power, Division of Omya Inc.; Central Vermont Public Service Corporation; Notice...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-10-19

...-029; 2445-023; 2558-029] Vermont Marble Power, Division of Omya Inc.; Central Vermont Public Service... Soliciting Comments and Motions To Intervene October 12, 2010. On August 31, 2010, Vermont Marble Power... relicensing. Applicant Contacts: For transferor: Todd Allard, Operations Engineer Omya, Inc., Vermont Marble...

Mapping and Engineering Functional Domains of the Assembly Activating Protein of Adeno-Associated Viruses.

PubMed

Tse, Longping V; Moller-Tank, Sven; Meganck, Rita M; Asokan, Aravind

2018-04-25

Adeno-associated viruses (AAV) encode a unique assembly activating protein (AAP) within their genome that is essential for capsid assembly. Studies to date have focused on establishing the role of AAP as a chaperone that mediates stability, nucleolar transport, and assembly of AAV capsid proteins. Here, we map structure-function correlates of AAP using secondary structure analysis followed by deletion and substitutional mutagenesis of specific domains, namely, the hydrophobic N-terminal domain (HR), conserved core (CC), proline-rich region (PRR), threonine/serine rich region (T/S) and basic region (BR). First, we establish that the centrally located PRR and T/S regions are flexible linker domains that can either be deleted completely or replaced by heterologous functional domains that enable ancillary functions such as fluorescent imaging or increased AAP stability. We also demonstrate that the C-terminal BR domains can be substituted with heterologous nuclear or nucleolar localization sequences that display varying ability to support AAV capsid assembly. Further, by replacing the BR domain with immunoglobulin (IgG) Fc domains, we assessed AAP complexation with AAV capsid subunits and demonstrate that the hydrophobic region (HR) and the conserved core (CC) in the AAP N-terminus are the sole determinants for viral protein (VP) recognition. However, VP recognition alone is not sufficient for capsid assembly. Our study sheds light on the modular structure-function correlates of AAP and provides multiple approaches to engineer AAP that might prove useful towards understanding and controlling AAV capsid assembly. Importance: Adeno-associated viruses (AAV) encode a unique assembly activating protein (AAP) within their genome that is essential for capsid assembly. Understanding how AAP acts as a chaperone for viral assembly could help improve efficiency and potentially control this process. Our studies reveal that AAP has a modular architecture, with each module playing a distinct role and can be engineered for carrying out new functions. Copyright © 2018 American Society for Microbiology.

A procedure for seismic risk reduction in Campania Region

NASA Astrophysics Data System (ADS)

Zuccaro, G.; Palmieri, M.; Maggiò, F.; Cicalese, S.; Grassi, V.; Rauci, M.

2008-07-01

The Campania Region has set and performed a peculiar procedure in the field of seismic risk reduction. Great attention has been paid to public strategic buildings such as town halls, civil protection buildings and schools. The Ordinance 3274 promulgate in the 2004 by the Italian central authority obliged the owners of strategic buildings to perform seismic analyses within 2008 in order to check the safety of the structures and the adequacy to the use. In the procedure the Campania region, instead of the local authorities, ensure the complete drafting of seismic checks through financial resources of the Italian Government. A regional scientific technical committee has been constituted, composed of scientific experts, academics in seismic engineering. The committee has drawn up guidelines for the processing of seismic analyses. At the same time, the Region has issued a public competition to select technical seismic engineering experts to appoint seismic analysis in accordance with guidelines. The scientific committee has the option of requiring additional documents and studies in order to approve the safety checks elaborated. The Committee is supported by a technical and administrative secretariat composed of a group of expert in seismic engineering. At the moment several seismic safety checks have been completed. The results will be presented in this paper. Moreover, the policy to mitigate the seismic risk, set by Campania region, was to spend the most of the financial resources available on structural strengthening of public strategic buildings rather than in safety checks. A first set of buildings of which the response under seismic action was already known by data and studies of vulnerability previously realised, were selected for immediate retrofitting designs. Secondly, an other set of buildings were identified for structural strengthening. These were selected by using the criteria specified in the Guide Line prepared by the Scientific Committee and based on data obtained by the first set of safety checks. The strengthening philosophy adopt in the projects will be described in the paper.

Ethical considerations for a better collaboration between architects and structural engineers: design of buildings with reinforced concrete frame systems in earthquake zones.

PubMed

Hurol, Yonca

2014-06-01

Architects design building structures, although structural design is the profession of structural engineers. Thus, it is better for architects and structural engineers to collaborate starting from the initial phases of the architectural design. However, this is not very common because of the contradictory design processes and value systems held within the two professions. This article provides a platform upon which architects and structural engineers can resolve the value conflicts between them by analysing phases of the structural design of reinforced concrete frame systems in architecture, the criteria of the structural design for each phase and determining the conflicting values for each criterion. The results shown in the article demonstrate that the architectural design of structures is a complex process, which is based on contradictory values and value systems. Finally, the article suggests to architects and structural engineers to use Value Sensitive Design and to choose an appropriate team leader in order to resolve the unethical conflict between them and to avoid any unreasonable decision making.

Computational structural mechanics engine structures computational simulator

NASA Technical Reports Server (NTRS)

Chamis, C. C.

1989-01-01

The Computational Structural Mechanics (CSM) program at Lewis encompasses: (1) fundamental aspects for formulating and solving structural mechanics problems, and (2) development of integrated software systems to computationally simulate the performance/durability/life of engine structures.

Assessment of modal-pushover-based scaling procedure for nonlinear response history analysis of ordinary standard bridges

USGS Publications Warehouse

Kalkan, E.; Kwong, N.

2012-01-01

The earthquake engineering profession is increasingly utilizing nonlinear response history analyses (RHA) to evaluate seismic performance of existing structures and proposed designs of new structures. One of the main ingredients of nonlinear RHA is a set of ground motion records representing the expected hazard environment for the structure. When recorded motions do not exist (as is the case in the central United States) or when high-intensity records are needed (as is the case in San Francisco and Los Angeles), ground motions from other tectonically similar regions need to be selected and scaled. The modal-pushover-based scaling (MPS) procedure was recently developed to determine scale factors for a small number of records such that the scaled records provide accurate and efficient estimates of “true” median structural responses. The adjective “accurate” refers to the discrepancy between the benchmark responses and those computed from the MPS procedure. The adjective “efficient” refers to the record-to-record variability of responses. In this paper, the accuracy and efficiency of the MPS procedure are evaluated by applying it to four types of existing Ordinary Standard bridges typical of reinforced concrete bridge construction in California. These bridges are the single-bent overpass, multi-span bridge, curved bridge, and skew bridge. As compared with benchmark analyses of unscaled records using a larger catalog of ground motions, it is demonstrated that the MPS procedure provided an accurate estimate of the engineering demand parameters (EDPs) accompanied by significantly reduced record-to-record variability of the EDPs. Thus, it is a useful tool for scaling ground motions as input to nonlinear RHAs of Ordinary Standard bridges.

Documentation for assessment of modal pushover-based scaling procedure for nonlinear response history analysis of "ordinary standard" bridges

USGS Publications Warehouse

Kalkan, Erol; Kwong, Neal S.

2010-01-01

The earthquake engineering profession is increasingly utilizing nonlinear response history analyses (RHA) to evaluate seismic performance of existing structures and proposed designs of new structures. One of the main ingredients of nonlinear RHA is a set of ground-motion records representing the expected hazard environment for the structure. When recorded motions do not exist (as is the case for the central United States), or when high-intensity records are needed (as is the case for San Francisco and Los Angeles), ground motions from other tectonically similar regions need to be selected and scaled. The modal-pushover-based scaling (MPS) procedure recently was developed to determine scale factors for a small number of records, such that the scaled records provide accurate and efficient estimates of 'true' median structural responses. The adjective 'accurate' refers to the discrepancy between the benchmark responses and those computed from the MPS procedure. The adjective 'efficient' refers to the record-to-record variability of responses. Herein, the accuracy and efficiency of the MPS procedure are evaluated by applying it to four types of existing 'ordinary standard' bridges typical of reinforced-concrete bridge construction in California. These bridges are the single-bent overpass, multi span bridge, curved-bridge, and skew-bridge. As compared to benchmark analyses of unscaled records using a larger catalog of ground motions, it is demonstrated that the MPS procedure provided an accurate estimate of the engineering demand parameters (EDPs) accompanied by significantly reduced record-to-record variability of the responses. Thus, the MPS procedure is a useful tool for scaling ground motions as input to nonlinear RHAs of 'ordinary standard' bridges.

Scanning the potential energy surface for synthesis of dendrimer-wrapped gold clusters: design rules for true single-molecule nanostructures.

PubMed

Thompson, Damien; Hermes, Jens P; Quinn, Aidan J; Mayor, Marcel

2012-04-24

The formation of true single-molecule complexes between organic ligands and nanoparticles is challenging and requires careful design of molecules with size, shape, and chemical properties tailored for the specific nanoparticle. Here we use computer simulations to describe the atomic-scale structure, dynamics, and energetics of ligand-mediated synthesis and interlinking of 1 nm gold clusters. The models help explain recent experimental results and provide insight into how multidentate thioether dendrimers can be employed for synthesis of true single-ligand-nanoparticle complexes and also nanoparticle-molecule-nanoparticle "dumbbell" nanostructures. Electronic structure calculations reveal the individually weak thioether-gold bonds (325 ± 36 meV), which act collectively through the multivalent (multisite) anchoring to stabilize the ligand-nanoparticle complex (∼7 eV total binding energy) and offset the conformational and solvation penalties involved in this "wrapping" process. Molecular dynamics simulations show that the dendrimer is sufficiently flexible to tolerate the strained conformations and desolvation penalties involved in fully wrapping the particle, quantifying the subtle balance between covalent anchoring and noncovalent wrapping in the assembly of ligand-nanoparticle complexes. The computed preference for binding of a single dendrimer to the cluster reveals the prohibitively high dendrimer desolvation barrier (1.5 ± 0.5 eV) to form the alternative double-dendrimer structure. Finally, the models show formation of an additional electron transfer channel between nitrogen and gold for ligands with a central pyridine unit, which gives a stiff binding orientation and explains the recently measured larger interparticle distances for particles synthesized and interlinked using linear ligands with a central pyridine rather than a benzene moiety. The findings stress the importance of organic-inorganic interactions, the control of which is central to the rational engineering and eventual large-scale production of functional building blocks for nano(bio)electronics.

Evaluating Contaminant Flux from the Vadose Zone to the Groundwater in the Hanford Central Plateau. SX Tank Farms Case Study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Truex, Michael J.; Oostrom, Martinus; Last, George V.

At the DOE Hanford Site, contaminants were discharged to the subsurface through engineered waste sites in the Hanford Central Plateau. Additional waste was released through waste storage tank leaks. Much of the contaminant inventory is still present within the unsaturated vadose zone sediments. The nature and extent of future groundwater contaminant plumes and the growth or decline of current groundwater plumes beneath the Hanford Central Plateau are a function of the contaminant flux from the vadose zone to the groundwater. In general, contaminant transport is slow through the vadose zone and it is difficult to directly measure contaminant flux inmore » the vadose zone. Predictive analysis, supported by site characterization and monitoring data, was applied using a structured, systems-based approach to estimate the future contaminant flux to groundwater in support of remediation decisions for the vadose zone and groundwater (Truex and Carroll 2013). The SX Tank Farm was used as a case study because of the existing contaminant inventory in the vadose zone, observations of elevated moisture content in portions of the vadose zone, presence of a limited-extent groundwater plume, and the relatively large amount and wide variety of data available for the site. Although the SX Tank Farm case study is most representative of conditions at tank farm sites, the study has elements that are also relevant to other types of disposal sites in the Hanford Central Plateau.« less

Clarification of Institutional Controls at the Rocky Flats Site Central Operable Unit and Implementation of the Soil Disturbance Review Plan - 13053

DOE Office of Scientific and Technical Information (OSTI.GOV)

DiSalvo, Rick; Surovchak, Scott; Spreng, Carl

2013-07-01

Cleanup and closure of DOE's Rocky Flats Site in Colorado, which was placed on the CERCLA National Priority List in 1989, was accomplished under CERCLA, RCRA, and the Colorado Hazardous Waste Act (CHWA). The physical cleanup work was completed in late 2005 and all buildings and other structures that composed the Rocky Flats industrial complex were removed from the surface, but remnants remain in the subsurface. Other remaining features include two landfills closed in place with covers, four groundwater treatment systems, and surface water and groundwater monitoring systems. Under the 2006 Corrective Action Decision/Record of Decision for Rocky Flats Plantmore » (US DOE) Peripheral Operable Unit and the Central Operable Unit (CAD/ROD), the response actions selected for the Central Operable Unit (OU) are institutional controls (ICs), physical controls, and continued monitoring and maintenance. The objectives of these ICs were to prevent unacceptable exposure to remaining subsurface contamination and to prevent contaminants from mobilizing to surface water and to prevent interfering with the proper functioning of the engineered components of the remedy. An amendment in 2011 of the 2006 CAD/ROD clarified the ICs to prevent misinterpretation that would prohibit work to manage and maintain the Central OU property. The 2011 amendment incorporated a protocol for a Soil Disturbance Review Plan for work subject to ICs that requires approval from the State and public notification by DOE prior to conducting approved soil-disturbing work. (authors)« less

Polarimetric imaging of NGC 1068 at high angular resolution in the near infrared. Direct evidence of an extended nuclear torus

NASA Astrophysics Data System (ADS)

Gratadour, D.; Rouan, D.; Grosset, L.; Boccaletti, A.; Clénet, Y.

2015-09-01

Aims: One of the main observational challenges for investigating the central regions of active galactic nuclei (AGN) at short wavelengths, using high angular resolution, and high contrast observations, is to directly detect the circumnuclear optically thick material hiding the central core emission when viewed edge-on. The lack of direct evidence is limiting our understanding of AGN, and several scenarios have been proposed to cope for the diverse observed aspects of activity in a unified approach. Methods: Observations in the near-infrared spectral range have shown themselves to be powerful for providing essential hints to the characterisation of the unified model ingredients because of the reduced optical depth of the obscuring material. Moreover, it is possible to trace this material through light scattered from the central engine's closest environment, so that polarimetric observations are the ideal tool for distinguishing it from purely thermal and stellar emissions. Results: Here we show strong evidence that there is an extended nuclear torus at the center of NGC 1068 thanks to new adaptive-optics-assisted polarimetric observations in the near-infrared. The orientation of the polarization vectors proves that there is a structured hourglass-shaped bicone and a compact elongated (20 × 60 pc) nuclear structure perpendicular to the bicone axis. The linearly polarized emission in the bicone is dominated by a centro-symmetric pattern, but the central compact region shows a clear deviation from the latter with linear polarization aligned perpendicular to the bicone axis. Figure 2 is available in electronic form at http://www.aanda.orgData obtained with the SPHERE an instrument designed and built by a consortium consisting of IPAG (France), MPIA (Germany), LAM (France), LESIA (France), Laboratoire Lagrange (France), INAF - Osservatorio di Padova (Italy), Observatoire de Genève (Switzerland), ETH Zurich (Switzerland), NOVA (Netherlands), ONERA (France), and ASTRON (Netherlands) in collaboration with ESO.

Engineering Low-Dimensional Nanostructures Towards Flexible Electronics

NASA Astrophysics Data System (ADS)

Byrley, Peter Samuel

Flexible electronics have been proposed as the next generation of electronic devices. They have advantages over traditional electronics in that they use less material, are more durable and have greater versatility in their proposed applications. However, there are a variety of types of devices being developed that have specific engineering challenges. This dissertation addresses two of those challenges. The first challenge involves lowering contact resistance in MoS2 based flexible thin film transistor devices using a photochemical phase change method while the second addresses using silver nanowire networks as a replacement flexible electrode for indium tin oxide in flexible electronics. In this dissertation, a scalable method was developed for making monolayer MoS2 using ambient pressure chemical vapor deposition. These films were then characterized using spectroscopic techniques and atomic force microscopy. A photochemical phase change mechanism was then proposed to improve contact resistance in MoS2 based devices. The central hypothesis is that the controllable partial transition from a semiconducting 2H to metallic 1T phase can be realized in monolayer TMDs through photo-reduction in the presence of hole scavenging chemicals. Phase-engineering in monolayer TMDs would enable the fabrication of high-quality heterophase structures with the potential to improve carrier mobility and contact. Phase change as a result of the proposed photochemical method was confirmed using Raman spectroscopy, photoluminescence measurements, X-Ray photoelectron spectroscopy and other supporting data. Gold coated silver nanowires were then created to serve as flexible nanowire based electrodes by overcoming galvanic replacement in solution. This was confirmed using various forms of electron microscopy. The central hypothesis is that a thin gold coating will enable silver nanowire meshes to remain electrically stable in atmosphere and retain necessary low resistance values and transparencies over time. It was shown that gold coated silver nanowire meshes could be created with sheet resistances comparable to indium tin oxide and outlast their bare silver nanowire counterparts in environments at 80 deg C.

Architecturing hierarchical function layers on self-assembled viral templates as 3D nano-array electrodes for integrated Li-ion microbatteries.

PubMed

Liu, Yihang; Zhang, Wei; Zhu, Yujie; Luo, Yanting; Xu, Yunhua; Brown, Adam; Culver, James N; Lundgren, Cynthia A; Xu, Kang; Wang, Yuan; Wang, Chunsheng

2013-01-09

This work enables an elegant bottom-up solution to engineer 3D microbattery arrays as integral power sources for microelectronics. Thus, multilayers of functional materials were hierarchically architectured over tobacco mosaic virus (TMV) templates that were genetically modified to self-assemble in a vertical manner on current-collectors, so that optimum power and energy densities accompanied with excellent cycle-life could be achieved on a minimum footprint. The resultant microbattery based on self-aligned LiFePO(4) nanoforests of shell-core-shell structure, with precise arrangement of various auxiliary material layers including a central nanometric metal core as direct electronic pathway to current collector, delivers excellent energy density and stable cycling stability only rivaled by the best Li-ion batteries of conventional configurations, while providing rate performance per foot-print and on-site manufacturability unavailable from the latter. This approach could open a new avenue for microelectromechanical systems (MEMS) applications, which would significantly benefit from the concept that electrochemically active components be directly engineered and fabricated as an integral part of the integrated circuit (IC).

Planetary boundaries and environmental citizenship: enhancing environmental science through the Princeton University Science and Engineering Education Initiative

NASA Astrophysics Data System (ADS)

Riihimaki, C. A.; Caylor, K. K.; Wilcove, D. S.

2014-12-01

Introductory courses in environmental science are challenging to teach effectively because instructors need to balance the breadth of content coverage with the depth needed to solve complex, interdisciplinary environmental problems. For three years, the Council on Science and Technology at Princeton University has been collaborating with faculty to enhance the introductory environmental science course as part of the Science and Engineering Education Initiative, which aims to ensure that all students, regardless of discipline, graduate with an appreciation for and literacy in science and engineering. Our primary aim in the course is to foster improved environmental citizenship by helping students develop a mechanistic understanding of our individual, societal, and global role as agents of environmental change; an ability to predict or forecast the potential impact that decisions may have on the future structure and function of Earth systems; and a sense of responsibility that leads to informed action and decision-making related to environmental issues. Toward those ends, we have 1) reframed the course curriculum to focus on the central theme of "planetary boundaries" (Rockstrom et al., 2009), including their scientific evidence and policy implications, 2) developed hands-on laboratory exercises that give students authentic research experiences, and 3) modified the assessment to ensure that the students have consistent and clear indications of their mastery of the material. Student feedback through course surveys has been positive, although challenges remain, including coordination across a large teaching staff (two lead instructors for lecture and three TAs for discussion sections, plus a lead lab instructor and one lab TA), optimizing learning activities across the course structure (lecture, precept, and an optional lab), and engaging students that have diverse academic interests.

Integrated gas turbine engine-nacelle

NASA Technical Reports Server (NTRS)

Adamson, A. P.; Sargisson, D. F.; Stotler, C. L., Jr. (Inventor)

1979-01-01

A nacelle for use with a gas turbine engine is provided with an integral webbed structure resembling a spoked wheel for rigidly interconnecting the nacelle and engine. The nacelle is entirely supported in its spacial relationship with the engine by means of the webbed structure. The inner surface of the nacelle defines the outer limits of the engine motive fluid flow annulus, while the outer surface of the nacelle defines a streamlined envelope for the engine.

Lignin engineering in field-grown poplar trees affects the endosphere bacterial microbiome.

PubMed

Beckers, Bram; Op De Beeck, Michiel; Weyens, Nele; Van Acker, Rebecca; Van Montagu, Marc; Boerjan, Wout; Vangronsveld, Jaco

2016-02-23

Cinnamoyl-CoA reductase (CCR), an enzyme central to the lignin biosynthetic pathway, represents a promising biotechnological target to reduce lignin levels and to improve the commercial viability of lignocellulosic biomass. However, silencing of the CCR gene results in considerable flux changes of the general and monolignol-specific lignin pathways, ultimately leading to the accumulation of various extractable phenolic compounds in the xylem. Here, we evaluated host genotype-dependent effects of field-grown, CCR-down-regulated poplar trees (Populus tremula × Populus alba) on the bacterial rhizosphere microbiome and the endosphere microbiome, namely the microbiota present in roots, stems, and leaves. Plant-associated bacteria were isolated from all plant compartments by selective isolation and enrichment techniques with specific phenolic carbon sources (such as ferulic acid) that are up-regulated in CCR-deficient poplar trees. The bacterial microbiomes present in the endosphere were highly responsive to the CCR-deficient poplar genotype with remarkably different metabolic capacities and associated community structures compared with the WT trees. In contrast, the rhizosphere microbiome of CCR-deficient and WT poplar trees featured highly overlapping bacterial community structures and metabolic capacities. We demonstrate the host genotype modulation of the plant microbiome by minute genetic variations in the plant genome. Hence, these interactions need to be taken into consideration to understand the full consequences of plant metabolic pathway engineering and its relation with the environment and the intended genetic improvement.

Effect of ethyleneoxide groups of anionic surfactants on lipase activity.

PubMed

Magalhães, Solange S; Alves, Luís; Sebastião, Marco; Medronho, Bruno; Almeida, Zaida L; Faria, Tiago Q; Brito, Rui M M; Moreno, Maria J; Antunes, Filipe E

2016-09-01

The use of enzymes in laundry and dish detergent products is growing. Such tendency implies dedicated studies to understand surfactant-enzyme interactions. The interactions between surfactants and enzymes and their impact on the catalytic efficiency represent a central problem and were here evaluated using circular dichroism, dynamic light scattering, and enzyme activity determinations. This work focuses on this key issue by evaluating the role of the ethyleneoxide (EO) groups of anionic surfactants on the structure and activity of a commercial lipase, and by focusing on the protein/surfactant interactions at a molecular level. The conformational changes and enzymatic activity of the protein were evaluated in the presence of sodium dodecyl sulfate (SDS also denoted as SLE 0 S) and of sodium lauryl ether sulfate with two EO units (SLE 2 S). The results strongly suggest that the presence of EO units in the surfactant polar headgroup determines the stability and the activity of the enzyme. While SDS promotes enzyme denaturation and consequent loss of activity, SLE 2 S preserves the enzyme structure and activity. The data further highlights that the electrostatic interactions among the protein groups are changed by the presence of the adsorbed anionic surfactants being such absorption mainly driven by hydrophobic interactions. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:1276-1282, 2016. © 2016 American Institute of Chemical Engineers.

Closeup view of the aft fuselage of the Orbiter Discovery ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Close-up view of the aft fuselage of the Orbiter Discovery looking at the thrust structure that supports the Space Shuttle Main Engines (SSMEs). In this view, SSME number two position is on the left and SSME number three position is on the right. The thrust structure transfers the forces produce by the engines into and through the airframe of the orbiter. The thrust structure includes the SSMEs load reaction truss structure, engine interface fittings and the hydraulic-actuator support structure. The propellant feed lines are the plugged and capped orifices within the engine bays. Note that SSME position two is rotated ninety degrees from position three and one. This was needed to enable enough clearance for the engines to fit and gimbal. Note in engine bay three is a clear view of the actuators that control the gambling of that engine. This view was taken from a service platform in the Orbiter Processing Facility at Kennedy Space Center. - Space Transportation System, Orbiter Discovery (OV-103), Lyndon B. Johnson Space Center, 2101 NASA Parkway, Houston, Harris County, TX

Structure of the knowledge base for an expert labeling system

NASA Technical Reports Server (NTRS)

Rajaram, N. S.

1981-01-01

One of the principal objectives of the NASA AgRISTARS program is the inventory of global crop resources using remotely sensed data gathered by Land Satellites (LANDSAT). A central problem in any such crop inventory procedure is the interpretation of LANDSAT images and identification of parts of each image which are covered by a particular crop of interest. This task of labeling is largely a manual one done by trained human analysts and consequently presents obstacles to the development of totally automated crop inventory systems. However, development in knowledge engineering as well as widespread availability of inexpensive hardware and software for artificial intelligence work offers possibilities for developing expert systems for labeling of crops. Such a knowledge based approach to labeling is presented.

Geometrical frustration yields fibre formation in self-assembly

NASA Astrophysics Data System (ADS)

Lenz, Martin; Witten, Thomas A.

2017-11-01

Controlling the self-assembly of supramolecular structures is vital for living cells, and a central challenge for engineering at the nano- and microscales. Nevertheless, even particles without optimized shapes can robustly form well-defined morphologies. This is the case in numerous medical conditions where normally soluble proteins aggregate into fibres. Beyond the diversity of molecular mechanisms involved, we propose that fibres generically arise from the aggregation of irregular particles with short-range interactions. Using a minimal model of ill-fitting, sticky particles, we demonstrate robust fibre formation for a variety of particle shapes and aggregation conditions. Geometrical frustration plays a crucial role in this process, and accounts for the range of parameters in which fibres form as well as for their metastable character.

Radiation Insulation

NASA Technical Reports Server (NTRS)

1995-01-01

The Apollo and subsequent spacecraft have had highly effective radiation barriers; made of aluminized polymer film, they bar or let in heat to maintain consistent temperatures inside. Tech 2000, formerly Quantum International Corporation used the NASA technology in its insulating materials, Super "Q" Radiant Barrier, for home, industry and mobile applications. The insulation combines industrial aluminum foil overlaid around a core of another material, usually propylene or mylar. The outer layer reflects up to 97 percent of heat; the central layer creates a thermal break in the structure and thus allows low radiant energy emission. The Quantum Cool Wall, used in cars and trucks, takes up little space while providing superior insulation, thus reducing spoilage and costs. The panels can also dampen sound and engine, exhaust and solar heat.

Assessing the Workforce Outcomes of Maryland Science, Technology, Engineering, and Math (STEM) Postsecondary Graduates

ERIC Educational Resources Information Center

Zheng, Xiaying; Stapleton, Laura M.; Henneberger, Angela K.; Woolley, Michael E.

2016-01-01

The science, technology, engineering, and math (STEM) workforce, and therefore STEM education, has become increasingly central to the U.S. economic growth and competitiveness over the past five decades. Nationally, the number of STEM workforce positions and the number of STEM postsecondary graduates have increased over time, but there is…

The National Science Foundation Strategic Framework for Investments in Graduate Education. FY 2016-FY 2020. Revised

ERIC Educational Resources Information Center

National Science Foundation, 2016

2016-01-01

Graduate education plays a central role in advancing the Nation's science and engineering research enterprise. It is also increasingly the means by which the Nation develops a diverse and highly technical Science Technology Engineering and Mathematics (STEM) professional workforce. The view that graduate education in STEM disciplines is an…

Language Aspects of Engineering Students' View of Entropy

ERIC Educational Resources Information Center

Haglund, Jesper; Andersson, Staffan; Elmgren, Maja

2016-01-01

Entropy is a central concept in thermodynamics, but has been found to be challenging to students due to its abstract nature and the fact that it is not part of students' everyday language. Interviews with three pairs of engineering students (N = 6) were conducted and video recorded regarding their interpretation and use of the entropy concept, one…

Geological Character and Mineral Resources of South Central Lake Erie.

DTIC Science & Technology

1982-10-01

Presque Isle Peninsula, Erie , Pennsylvania , being conducted by the U.S. Army Engineer District...the Pennsylvania shoreline. Because of its position and morphology, Presque Isle acts as a natural offshore breakwater for Erie Harbor, blocking the...Research Center, Fort Belvoir, Va. (in preparation, 1982). U.S. ARMY ENGINEER DISTRICT, BUFFALO, " Presque Isle Peninsula, Erie , Pennsylvania ,"

Designing "Design Squad": Developing and Assessing a Children's Television Program about Engineering

ERIC Educational Resources Information Center

Frey, Daniel David; Powers, Benjamin

2012-01-01

This paper describes a multi-media outreach campaign intended to increase children's knowledge of engineering and to improve the public image of the profession. The central element is a reality-based show entitled "Design Squad," whose first season was broadcast on public television stations beginning in the spring of 2007. The show was…

Observing Engineering Student Teams from the Organization Behavior Perspective Using Linguistic Analysis of Student Reflections and Focus Group Interviews

ERIC Educational Resources Information Center

Kearney, Kerri S.; Damron, Rebecca; Sohoni, Sohum

2015-01-01

This paper investigates group/team development in computer engineering courses at a University in the Central USA from the perspective of organization behavior theory, specifically Tuckman's model of the stages of group development. The investigation, conducted through linguistic analysis of student reflection essays, and through focus group…

Domain motions of Argonaute, the catalytic engine of RNA interference

PubMed Central

Ming, Dengming; Wall, Michael E; Sanbonmatsu, Kevin Y

2007-01-01

Background The Argonaute protein is the core component of the RNA-induced silencing complex, playing the central role of cleaving the mRNA target. Visual inspection of static crystal structures already has enabled researchers to suggest conformational changes of Argonaute that might occur during RNA interference. We have taken the next step by performing an all-atom normal mode analysis of the Pyrococcus furiosus and Aquifex aeolicus Argonaute crystal structures, allowing us to quantitatively assess the feasibility of these conformational changes. To perform the analysis, we begin with the energy-minimized X-ray structures. Normal modes are then calculated using an all-atom molecular mechanics force field. Results The analysis reveals low-frequency vibrations that facilitate the accommodation of RNA duplexes – an essential step in target recognition. The Pyrococcus furiosus and Aquifex aeolicus Argonaute proteins both exhibit low-frequency torsion and hinge motions; however, differences in the overall architecture of the proteins cause the detailed dynamics to be significantly different. Conclusion Overall, low-frequency vibrations of Argonaute are consistent with mechanisms within the current reaction cycle model for RNA interference. PMID:18053142

Dynamic analysis of suspension cable based on vector form intrinsic finite element method

NASA Astrophysics Data System (ADS)

Qin, Jian; Qiao, Liang; Wan, Jiancheng; Jiang, Ming; Xia, Yongjun

2017-10-01

A vector finite element method is presented for the dynamic analysis of cable structures based on the vector form intrinsic finite element (VFIFE) and mechanical properties of suspension cable. Firstly, the suspension cable is discretized into different elements by space points, the mass and external forces of suspension cable are transformed into space points. The structural form of cable is described by the space points at different time. The equations of motion for the space points are established according to the Newton’s second law. Then, the element internal forces between the space points are derived from the flexible truss structure. Finally, the motion equations of space points are solved by the central difference method with reasonable time integration step. The tangential tension of the bearing rope in a test ropeway with the moving concentrated loads is calculated and compared with the experimental data. The results show that the tangential tension of suspension cable with moving loads is consistent with the experimental data. This method has high calculated precision and meets the requirements of engineering application.

Domain motions of Argonaute, the catalytic engine of RNA interference.

PubMed

Ming, Dengming; Wall, Michael E; Sanbonmatsu, Kevin Y

2007-11-30

The Argonaute protein is the core component of the RNA-induced silencing complex, playing the central role of cleaving the mRNA target. Visual inspection of static crystal structures already has enabled researchers to suggest conformational changes of Argonaute that might occur during RNA interference. We have taken the next step by performing an all-atom normal mode analysis of the Pyrococcus furiosus and Aquifex aeolicus Argonaute crystal structures, allowing us to quantitatively assess the feasibility of these conformational changes. To perform the analysis, we begin with the energy-minimized X-ray structures. Normal modes are then calculated using an all-atom molecular mechanics force field. The analysis reveals low-frequency vibrations that facilitate the accommodation of RNA duplexes - an essential step in target recognition. The Pyrococcus furiosus and Aquifex aeolicus Argonaute proteins both exhibit low-frequency torsion and hinge motions; however, differences in the overall architecture of the proteins cause the detailed dynamics to be significantly different. Overall, low-frequency vibrations of Argonaute are consistent with mechanisms within the current reaction cycle model for RNA interference.

Femtosecond laser-induced periodic surface structures on steel and titanium alloy for tribological applications

NASA Astrophysics Data System (ADS)

Bonse, J.; Koter, R.; Hartelt, M.; Spaltmann, D.; Pentzien, S.; Höhm, S.; Rosenfeld, A.; Krüger, J.

2014-10-01

Laser-induced periodic surface structures (LIPSS, ripples) were generated on stainless steel (100Cr6) and titanium alloy (Ti6Al4V) surfaces upon irradiation with multiple femtosecond laser pulses (pulse duration 30 fs, central wavelength 790 nm). The experimental conditions (laser fluence, spatial spot overlap) were optimized in a sample-scanning geometry for the processing of large surface areas (5 × 5 mm2) covered homogeneously by the nanostructures. The irradiated surface regions were subjected to white light interference microscopy and scanning electron microscopy revealing spatial periods around 600 nm. The tribological performance of the nanostructured surface was characterized by reciprocal sliding against a ball of hardened steel in paraffin oil and in commercial engine oil as lubricants, followed by subsequent inspection of the wear tracks. For specific conditions, on the titanium alloy a significant reduction of the friction coefficient by a factor of more than two was observed on the laser-irradiated (LIPSS-covered) surface when compared to the non-irradiated one, indicating the potential benefit of laser surface structuring for tribological applications.

F101 Central Integrated Test Subsystem Evaluation.

DTIC Science & Technology

1980-02-01

These sensors are for fan rpm, core rpm, nozzle position, turbine blade temperature, engine exhaust gas tem- perature, lube oil pressure, lube oil...condition or a turbine blade (T4B) overtemperature condition, the CITS was to record the out-of-limits parameter every quarter-second that the engine was in...cycles on the turbine blades . The PLA cycle has become the most important LCF measurement to the YF101 and F1O engines in the B-1 Flight Test Program

Methodology for the systems engineering process. Volume 1: System functional activities

NASA Technical Reports Server (NTRS)

Nelson, J. H.

1972-01-01

Systems engineering is examined in terms of functional activities that are performed in the conduct of a system definition/design, and system development is described in a parametric analysis that combines functions, performance, and design variables. Emphasis is placed on identification of activities performed by design organizations, design specialty groups, as well as a central systems engineering organizational element. Identification of specific roles and responsibilities for doing functions, and monitoring and controlling activities within the system development operation are also emphasized.

Introduction: seismology and earthquake engineering in Mexico and Central and South America.

USGS Publications Warehouse

Espinosa, A.F.

1982-01-01

The results from seismological studies that are used by the engineering community are just one of the benefits obtained from research aimed at mitigating the earthquake hazard. In this issue of Earthquake Information Bulletin current programs in seismology and earthquake engineering, seismic networks, future plans and some of the cooperative programs with different internation organizations are described by Latin-American seismologists. The article describes the development of seismology in Latin America and the seismological interest of the OAS. -P.N.Chroston

Revisiting the TALE repeat.

PubMed

Deng, Dong; Yan, Chuangye; Wu, Jianping; Pan, Xiaojing; Yan, Nieng

2014-04-01

Transcription activator-like (TAL) effectors specifically bind to double stranded (ds) DNA through a central domain of tandem repeats. Each TAL effector (TALE) repeat comprises 33-35 amino acids and recognizes one specific DNA base through a highly variable residue at a fixed position in the repeat. Structural studies have revealed the molecular basis of DNA recognition by TALE repeats. Examination of the overall structure reveals that the basic building block of TALE protein, namely a helical hairpin, is one-helix shifted from the previously defined TALE motif. Here we wish to suggest a structure-based re-demarcation of the TALE repeat which starts with the residues that bind to the DNA backbone phosphate and concludes with the base-recognition hyper-variable residue. This new numbering system is consistent with the α-solenoid superfamily to which TALE belongs, and reflects the structural integrity of TAL effectors. In addition, it confers integral number of TALE repeats that matches the number of bound DNA bases. We then present fifteen crystal structures of engineered dHax3 variants in complex with target DNA molecules, which elucidate the structural basis for the recognition of bases adenine (A) and guanine (G) by reported or uncharacterized TALE codes. Finally, we analyzed the sequence-structure correlation of the amino acid residues within a TALE repeat. The structural analyses reported here may advance the mechanistic understanding of TALE proteins and facilitate the design of TALEN with improved affinity and specificity.

Enhanced pyruvate production in Candida glabrata by carrier engineering.

PubMed

Luo, Zhengshan; Liu, Song; Du, Guocheng; Xu, Sha; Zhou, Jingwen; Chen, Jian

2018-02-01

Pyruvate is an important organic acid that plays a key role in the central metabolic pathway. Manipulating transporters is an efficient strategy to enhance production of target organic acids and a means to understand the effects of altered intracellular pyruvate content on global metabolic networks. Efforts have been made to manipulate mitochondrial pyruvate carrier (MPC) to transport pyruvate into different subcellular compartments in Candida glabrata to demonstrate the effects of the subcellular distribution of pyruvate on central carbon metabolism. By increasing the mitochondrial pyruvate content through enhancing the rate of pyruvate transport into mitochondria, a high central carbon metabolism rate, specific growth rate and specific pyruvate production rate were obtained. Comparing the intracellular pyruvate content of engineered and control strains showed that higher intracellular pyruvate levels were not conducive to improving pyruvate productivity or central carbon metabolism. Plasma membrane expression of MPCs significantly increased the expression levels of key rate-limiting glycolytic enzymes. Moreover, pyruvate production of CGΔura3-Sp-MPC1, CGΔura3-Sp-MPC2, and CGΔura3-Sp-MPC1-Sp-MPC2 increased 134.4%, 120.3%, and 30.0%, respectively. In conclusion, lower intracellular pyruvate content enhanced central carbon metabolism and provided useful clues for improving the production of other organic acids in microorganisms. © 2017 Wiley Periodicals, Inc.

New Compressor Added to Glenn's 450- psig Combustion Air System

NASA Technical Reports Server (NTRS)

Swan, Jeffrey A.

2000-01-01

In September 1999, the Central Process Systems Engineering Branch and the Maintenance and the Central Process Systems Operations Branch, released for service a new high pressure compressor to supplement the 450-psig Combustion Air System at the NASA Glenn Research Center at Lewis Field. The new compressor, designated C-18, is located in Glenn s Central Air Equipment Building and is remotely operated from the Central Control Building. C-18 can provide 40 pounds per second (pps) of airflow at pressure to our research customers. This capability augments our existing system capacity (compressors C 4 at 38 pps and C-5 at 32 pps), which is generated from Glenn's Engine Research Building. The C-18 compressor was originally part of Glenn's 21-Inch Hypersonic Tunnel, which was transferred from the Jet Propulsion Laboratory to Glenn in the mid-1980's. With the investment of construction of facilities funding, the compressor was modified, new mechanical and electrical support equipment were purchased, and the unit was installed in the basement of the Central Air Equipment Building. After several weeks of checkout and troubleshooting, the new compressor was ready for long-term, reliable operations. With a total of 110 pps in airflow now available, Glenn is well positioned to support the high-pressure air test requirements of our research customers.

Probabilistic Multi-Scale, Multi-Level, Multi-Disciplinary Analysis and Optimization of Engine Structures

NASA Technical Reports Server (NTRS)

Chamis, Christos C.; Abumeri, Galib H.

2000-01-01

Aircraft engines are assemblies of dynamically interacting components. Engine updates to keep present aircraft flying safely and engines for new aircraft are progressively required to operate in more demanding technological and environmental requirements. Designs to effectively meet those requirements are necessarily collections of multi-scale, multi-level, multi-disciplinary analysis and optimization methods and probabilistic methods are necessary to quantify respective uncertainties. These types of methods are the only ones that can formally evaluate advanced composite designs which satisfy those progressively demanding requirements while assuring minimum cost, maximum reliability and maximum durability. Recent research activities at NASA Glenn Research Center have focused on developing multi-scale, multi-level, multidisciplinary analysis and optimization methods. Multi-scale refers to formal methods which describe complex material behavior metal or composite; multi-level refers to integration of participating disciplines to describe a structural response at the scale of interest; multidisciplinary refers to open-ended for various existing and yet to be developed discipline constructs required to formally predict/describe a structural response in engine operating environments. For example, these include but are not limited to: multi-factor models for material behavior, multi-scale composite mechanics, general purpose structural analysis, progressive structural fracture for evaluating durability and integrity, noise and acoustic fatigue, emission requirements, hot fluid mechanics, heat-transfer and probabilistic simulations. Many of these, as well as others, are encompassed in an integrated computer code identified as Engine Structures Technology Benefits Estimator (EST/BEST) or Multi-faceted/Engine Structures Optimization (MP/ESTOP). The discipline modules integrated in MP/ESTOP include: engine cycle (thermodynamics), engine weights, internal fluid mechanics, cost, mission and coupled structural/thermal, various composite property simulators and probabilistic methods to evaluate uncertainty effects (scatter ranges) in all the design parameters. The objective of the proposed paper is to briefly describe a multi-faceted design analysis and optimization capability for coupled multi-discipline engine structures optimization. Results are presented for engine and aircraft type metrics to illustrate the versatility of that capability. Results are also presented for reliability, noise and fatigue to illustrate its inclusiveness. For example, replacing metal rotors with composites reduces the engine weight by 20 percent, 15 percent noise reduction, and an order of magnitude improvement in reliability. Composite designs exist to increase fatigue life by at least two orders of magnitude compared to state-of-the-art metals.

Drone Defense System Architecture for U.S. Navy Strategic Facilities

DTIC Science & Technology

2017-09-01

evaluation and weapons assignment (TEWA) to properly address threats. This report follows a systems engineering process to develop a software architecture...C-UAS requires a central system to connect these new and existing systems. The central system uses data fusion and threat evaluation and weapons...30  Table 6.  Decision Type Descriptions .......................................................................40  Table 7

Centralized waste treatment of industrial wastewater

DOE Office of Scientific and Technical Information (OSTI.GOV)

Saltzberg, E.R.; Cushnie, G.C. Jr.

1985-01-01

Centralized waste treatment (CWT) for industrial wastewater is described in this book. With the CWT approach, industrial firms send their wastes to a common processing plant. The book addresses the engineering and business-related problems that are encountered by private CWT firms, local governments, and industry in creating sufficient CWT capacity to meet the growing demand for CWT services.

A modernized high-pressure heater protection system for nuclear and thermal power stations

NASA Astrophysics Data System (ADS)

Svyatkin, F. A.; Trifonov, N. N.; Ukhanova, M. G.; Tren'kin, V. B.; Koltunov, V. A.; Borovkov, A. I.; Klyavin, O. I.

2013-09-01

Experience gained from operation of high-pressure heaters and their protection systems serving to exclude ingress of water into the turbine is analyzed. A formula for determining the time for which the high-pressure heater shell steam space is filled when a rupture of tubes in it occurs is analyzed, and conclusions regarding the high-pressure heater design most advisable from this point of view are drawn. A typical structure of protection from increase of water level in the shell of high-pressure heaters used in domestically produced turbines for thermal and nuclear power stations is described, and examples illustrating this structure are given. Shortcomings of components used in the existing protection systems that may lead to an accident at the power station are considered. A modernized protection system intended to exclude the above-mentioned shortcomings was developed at the NPO Central Boiler-Turbine Institute and ZioMAR Engineering Company, and the design solutions used in this system are described. A mathematical model of the protection system's main elements (the admission and check valves) has been developed with participation of specialists from the St. Petersburg Polytechnic University, and a numerical investigation of these elements is carried out. The design version of surge tanks developed by specialists of the Central Boiler-Turbine Institute for excluding false operation of the high-pressure heater protection system is proposed.

An L-band transit-time oscillator with mechanical frequency tunability

NASA Astrophysics Data System (ADS)

Song, Lili; He, Juntao; Ling, Junpu; Cao, Yibing

2017-02-01

An L-band coaxial Transit-time Oscillator (TTO) with mechanical frequency tunability is introduced in this paper. Particle-in-cell simulations have been done. The output power efficiency has been improved at least 20% under a 10.2 GW input power and with a tunable range from 1.57 GHz to 1.90 GHz by modulating the outer conductor. It is worth to note that the efficiency can reach as high as 41% at 1.75 GHz. The mechanical engineering method is also detailed in this work. The frequency tuning range of the coaxial TTO is 22.6% of the central frequency. On the other hand, the frequency can be tuned from 1.6 GHz to 1.85 GHz by modulating the inner conductor. The author highlights a hollow structure of the L-band coaxial TTO which can work from 1.03 GHz to 1.31 GHz via modulating the outer conductor in the rest of the article. The frequency tuning range of the hollow TTO is 21.4% of the central frequency. More importantly, the hollow TTO can be easily achieved after the inner conductor is removed from the coaxial TTO. The electric field distributions of the coaxial and hollow TTOs are analyzed, resulting in that the longitudinal and transverse working modes are TM01 and π mode, respectively. The same working mode from these two structures implies the stability of the TTOs mentioned above.

Structural Performance’s Optimally Analysing and Implementing Based on ANSYS Technology

NASA Astrophysics Data System (ADS)

Han, Na; Wang, Xuquan; Yue, Haifang; Sun, Jiandong; Wu, Yongchun

2017-06-01

Computer-aided Engineering (CAE) is a hotspot both in academic field and in modern engineering practice. Analysis System(ANSYS) simulation software for its excellent performance become outstanding one in CAE family, it is committed to the innovation of engineering simulation to help users to shorten the design process, improve product innovation and performance. Aimed to explore a structural performance’s optimally analyzing model for engineering enterprises, this paper introduced CAE and its development, analyzed the necessity for structural optimal analysis as well as the framework of structural optimal analysis on ANSYS Technology, used ANSYS to implement a reinforced concrete slab structural performance’s optimal analysis, which was display the chart of displacement vector and the chart of stress intensity. Finally, this paper compared ANSYS software simulation results with the measured results,expounded that ANSYS is indispensable engineering calculation tools.

Key issues in theoretical and functional pneumatic design

NASA Astrophysics Data System (ADS)

Xu, Z. G.; Yang, D. Y.; Liu, W. M.; Liu, T. T.

2017-10-01

This paper studies the energy release of the pneumatic engine in different thermodynamic processes, the isothermal process is the highest power output process, while adiabatic process is the lowest energy output process, and the energy release of the pneumatic engine is a multi-state thermodynamic process between them. Therefore heat exchanging should be increased between the pneumatic engine and the outer space, the gas expansion process in the cylinder should be as close as possible to the isothermal process. Heat exchange should be increased between the cylinder and the external spaces. Secondly, the fin structure is studied to increase the heat exchanging between the cylinder body and the outside space. The upper part has fin structures and the lower cylinder has no fin structure, this structure improved the working efficiency of pneumatic engine. Finally the cam and the hydraulic bottle of pneumatic engines are designed. Simulation and theoretical calculation are used to the analysis of the whole structure, which lay the foundation for the manufacturing and design of the pneumatic engines.

Lewis Structures Technology, 1988. Volume 2: Structural Mechanics

NASA Technical Reports Server (NTRS)

1988-01-01

Lewis Structures Div. performs and disseminates results of research conducted in support of aerospace engine structures. These results have a wide range of applicability to practitioners of structural engineering mechanics beyond the aerospace arena. The engineering community was familiarized with the depth and range of research performed by the division and its academic and industrial partners. Sessions covered vibration control, fracture mechanics, ceramic component reliability, parallel computing, nondestructive evaluation, constitutive models and experimental capabilities, dynamic systems, fatigue and damage, wind turbines, hot section technology (HOST), aeroelasticity, structural mechanics codes, computational methods for dynamics, structural optimization, and applications of structural dynamics, and structural mechanics computer codes.

Ballistic and Cyclic Rig Testing of Braided Composite Fan Case Structures

NASA Technical Reports Server (NTRS)

Watson, William R.; Roberts, Gary D.; Pereira, J. Michael; Braley, Michael S.

2015-01-01

FAA fan blade-out certification testing on turbofan engines occurs very late in an engine's development program and is very costly. It is of utmost importance to approach the FAA Certification engine test with a high degree of confidence that the containment structure will not only contain the high-energy debris, but that it will also withstand the cyclic loads that occur with engine spooldown and continued rotation as the non-running engine maintains a low rotor RPM due to forced airflow as the engine-out aircraft returns to an airport. Accurate rig testing is needed for predicting and understanding material behavior of the fan case structure during all phases of this fan blade-out event.

A Method for Search Engine Selection using Thesaurus for Selective Meta-Search Engine

NASA Astrophysics Data System (ADS)

Goto, Shoji; Ozono, Tadachika; Shintani, Toramatsu

In this paper, we propose a new method for selecting search engines on WWW for selective meta-search engine. In selective meta-search engine, a method is needed that would enable selecting appropriate search engines for users' queries. Most existing methods use statistical data such as document frequency. These methods may select inappropriate search engines if a query contains polysemous words. In this paper, we describe an search engine selection method based on thesaurus. In our method, a thesaurus is constructed from documents in a search engine and is used as a source description of the search engine. The form of a particular thesaurus depends on the documents used for its construction. Our method enables search engine selection by considering relationship between terms and overcomes the problems caused by polysemous words. Further, our method does not have a centralized broker maintaining data, such as document frequency for all search engines. As a result, it is easy to add a new search engine, and meta-search engines become more scalable with our method compared to other existing methods.

Structural dynamics verification facility study

NASA Technical Reports Server (NTRS)

Kiraly, L. J.; Hirchbein, M. S.; Mcaleese, J. M.; Fleming, D. P.

1981-01-01

The need for a structural dynamics verification facility to support structures programs was studied. Most of the industry operated facilities are used for highly focused research, component development, and problem solving, and are not used for the generic understanding of the coupled dynamic response of major engine subsystems. Capabilities for the proposed facility include: the ability to both excite and measure coupled structural dynamic response of elastic blades on elastic shafting, the mechanical simulation of various dynamical loadings representative of those seen in operating engines, and the measurement of engine dynamic deflections and interface forces caused by alternative engine mounting configurations and compliances.

Dermoscopy of accessory nipples in authors’ own study

PubMed Central

Szymszal, Jan; Silny, Wojciech

2014-01-01

Introduction The accessory nipple (AN) is characterised by its network-like structures, which may suggest the diagnosis of a melanocytic lesion. The knowledge about additional dermoscopic features of AN may greatly minimise the risk of unnecessary surgical excisions. Aim To analyse and present different clinical and dermoscopic forms, in which the AN may appear. Material and methods Ninety AN with dermoscopic features were evaluated in the study, detected in 14 patients between the years 2008 and 2014. Results The most common dermoscopic features of the AN were central, scar-like areas (15/19) and peripheral network-like structures (12/19). A number of cleft-like appearances (8/19) and central network-like structures (7/19) had also been observed. Moreover, among the dermoscopic features, white cobblestone-like structures (7/19), a central round dimpling with a plug (6/19) and fisheye-like structures resembling comedo-like openings (9/19) have all also been noted. There is a statistical significance in the occurrence of white cobblestone-like structures with central network-like structures (Fisher's exact test p = 0.0449). The presence of peripheral network-like structures with the occurrence of central scar-like areas was statistically highly significant (p = 0.0091). The central round dimpling was never observed alongside any central network-like structures in any of the lesions (p = 0.0436). Conclusions Accessory nipples are most commonly characterised by the occurrence of a peripheral network-like structure accompanied by the presence of a scar-like area. PMID:25097482

Ecological consequences of forest elephant declines for Afrotropical forests.

PubMed

Poulsen, John R; Rosin, Cooper; Meier, Amelia; Mills, Emily; Nuñez, Chase L; Koerner, Sally E; Blanchard, Emily; Callejas, Jennifer; Moore, Sarah; Sowers, Mark

2018-06-01

Poaching is rapidly extirpating African forest elephants (Loxodonta cyclotis) from most of their historical range, leaving vast areas of elephant-free tropical forest. Elephants are ecological engineers that create and maintain forest habitat; thus, their loss will have large consequences for the composition and structure of Afrotropical forests. Through a comprehensive literature review, we evaluated the roles of forest elephants in seed dispersal, nutrient recycling, and herbivory and physical damage to predict the cascading ecological effects of their population declines. Loss of seed dispersal by elephants will favor tree species dispersed abiotically and by smaller dispersal agents, and tree species composition will depend on the downstream effects of changes in elephant nutrient cycling and browsing. Loss of trampling and herbivory of seedlings and saplings will result in high tree density with release from browsing pressures. Diminished seed dispersal by elephants and high stem density are likely to reduce the recruitment of large trees and thus increase homogeneity of forest structure and decrease carbon stocks. The loss of ecological services by forest elephants likely means Central African forests will be more like Neotropical forests, from which megafauna were extirpated thousands of years ago. Without intervention, as much as 96% of Central African forests will have modified species composition and structure as elephants are compressed into remaining protected areas. Stopping elephant poaching is an urgent first step to mitigating these effects, but long-term conservation will require land-use planning that incorporates elephant habitat into forested landscapes that are being rapidly transformed by industrial agriculture and logging. © 2017 Society for Conservation Biology.

Integrating the protein and metabolic engineering toolkits for next-generation chemical biosynthesis.

PubMed

Pirie, Christopher M; De Mey, Marjan; Jones Prather, Kristala L; Ajikumar, Parayil Kumaran

2013-04-19

Through microbial engineering, biosynthesis has the potential to produce thousands of chemicals used in everyday life. Metabolic engineering and synthetic biology are fields driven by the manipulation of genes, genetic regulatory systems, and enzymatic pathways for developing highly productive microbial strains. Fundamentally, it is the biochemical characteristics of the enzymes themselves that dictate flux through a biosynthetic pathway toward the product of interest. As metabolic engineers target sophisticated secondary metabolites, there has been little recognition of the reduced catalytic activity and increased substrate/product promiscuity of the corresponding enzymes compared to those of central metabolism. Thus, fine-tuning these enzymatic characteristics through protein engineering is paramount for developing high-productivity microbial strains for secondary metabolites. Here, we describe the importance of protein engineering for advancing metabolic engineering of secondary metabolism pathways. This pathway integrated enzyme optimization can enhance the collective toolkit of microbial engineering to shape the future of chemical manufacturing.

Preparing engineers for the challenges of community engagement

NASA Astrophysics Data System (ADS)

Harsh, Matthew; Bernstein, Michael J.; Wetmore, Jameson; Cozzens, Susan; Woodson, Thomas; Castillo, Rafael

2017-11-01

Despite calls to address global challenges through community engagement, engineers are not formally prepared to engage with communities. Little research has been done on means to address this 'engagement gap' in engineering education. We examine the efficacy of an intensive, two-day Community Engagement Workshop for engineers, designed to help engineers better look beyond technology, listen to and learn from people, and empower communities. We assessed the efficacy of the workshop in a non-experimental pre-post design using a questionnaire and a concept map. Questionnaire results indicate participants came away better able to ask questions more broadly inclusive of non-technological dimensions of engineering projects. Concept map results indicate participants have a greater understanding of ways social factors shape complex material systems after completing the programme. Based on the workshop's strengths and weaknesses, we discuss the potential of expanding and supplementing the programme to help engineers account for social aspects central to engineered systems.

Site characterization and construction of a controlled shallow test site in central Mexico for archaeological and engineering applications

NASA Astrophysics Data System (ADS)

Rosado-Fuentes, A.; Arango-Galvan, C.; Arciniega-Ceballos, A.; Hernández-Quintero, J. E.; Mendo-Perez, G.

2017-12-01

A controlled shallow test site (CSTS) has been constructed at the UNAM Geomagnetic Observatory in Teoloyucan, central Mexico. The objective of the CSTS is to have a controlled place to test new developments and arrays that can be used for archaeological and engineering exploration, as well as to calibrate instruments, train students and for future research. The CSTS was built far enough not to influence the geomagnetic sensors and not be affected by noise sources. Special attention was given to the distribution and geometry of buried materials as well as the instruments used. Before the CSTS was built, a combination of near-surface, non-invasive geophysical techniques was performed to characterize the area of 20 by 32 meters. The methods include magnetometry, electromagnetic induction, ground penetrating radar (GPR), electrical resistivity tomography (ERT) and seismic refraction tomography (SRT). The GPR, SRT and ERT results show relatively flat interfaces. In general, the vertical gradient of the total magnetic field and the electric conductivity have very small variations, showing only one strong magnetic dipole associated to a shallow anomaly. These results indicate that the area is ideal for the construction of the test site. The CSTS consists on buried structures made with different materials and geometries (cubes, cylinders and tubes) commonly used as construction materials in Mexico since Pre-Hispanic times. These materials include concrete, reinforced concrete, wood, brick, adobe, basalt, tezontle and also empty space for controlling responses. The CSTS is versatile enough to be reshaped considering new geometries or materials and to conduct further investigations.

Relativistic simulations of long-lived reverse shocks in stratified ejecta: the origin of flares in GRB afterglows

NASA Astrophysics Data System (ADS)

Lamberts, A.; Daigne, F.

2018-02-01

The X-ray light curves of the early afterglow phase from gamma-ray bursts (GRBs) present a puzzling variability, including flares. The origin of these flares is still debated, and often associated with a late activity of the central engine. We discuss an alternative scenario where the central engine remains short-lived and flares are produced by the propagation of a long-lived reverse shock in a stratified ejecta. Here we focus on the hydrodynamics of the shock interactions. We perform one-dimensional ultrarelativistic hydrodynamic simulations with different initial internal structure in the GRB ejecta. We use them to extract bolometric light curves and compare with a previous study based on a simplified ballistic model. We find a good agreement between both approaches, with similar slopes and variability in the light curves, but identify several weaknesses in the ballistic model: the density is underestimated in the shocked regions, and more importantly, late shock reflections are not captured. With accurate dynamics provided by our hydrodynamic simulations, we confirm that internal shocks in the ejecta lead to the formation of dense shells. The interaction of the long-lived reverse shock with a dense shell then produces a fast and intense increase of the dissipated power. Assuming that the emission is due to the synchrotron radiation from shock-accelerated electrons, and that the external forward shock is radiatively inefficient, we find that this results in a bright flare in the X-ray light curve, with arrival times, shapes, and duration in agreement with the observed properties of X-ray flares in GRB afterglows.

Mathematics and its value for engineering students: what are the implications for teaching?

NASA Astrophysics Data System (ADS)

Harris, Diane; Black, Laura; Hernandez-Martinez, Paul; Pepin, Birgit; Williams, Julian; with the TransMaths Team

2015-04-01

Mathematics has long been known to be problematic for university engineering students and their teachers, for example, Scanlan.[1] This paper presents recent data gathered from interviews with engineering students who experienced problems with mathematics and their lecturers during their transition through the first year in different programme contexts. Our interviews with the students reveal how they understand the relation between engineering and mathematics and we draw on the concept of 'use- and exchange-value' to explore this relationship more fully. This paper challenges both the pedagogical practice of teaching non-contextualized mathematics and the lack of transparency regarding the significance of mathematics to engineering. We conclude that the value of mathematics in engineering remains a central problem, and argue that mathematics should be a fundamental concern in the design and practice of first-year engineering.

Ash Shutbah: A possible impact structure in Saudi Arabia

NASA Astrophysics Data System (ADS)

Gnos, Edwin; Hofmann, Beda A.; Schmieder, Martin; Al-Wagdani, Khalid; Mahjoub, Ayman; Al-Solami, Abdulaziz A.; Habibullah, Siddiq N.; Matter, Albert; Alwmark, Carl

2014-10-01

We have investigated the Ash Shutbah circular structure in central Saudi Arabia (21°37'N 45°39'E) using satellite imagery, field mapping, thin-section petrography, and X-ray diffraction of collected samples. The approximately 2.1 km sized structure located in flat-lying Jurassic Tuwaiq Mountain Limestone has been nearly peneplained by erosional processes. Satellite and structural data show a central area consisting of Dhruma Formation sandstones with steep bedding and tight folds plunging radially outward. Open folding occurs in displaced, younger Tuwaiq Mountain Limestone Formation blocks surrounding the central area, but is absent outside the circular structure. An approximately 60 cm thick, unique folded and disrupted orthoquartzitic sandstone marker bed occurring in the central area of the structure is found 140 m deeper in undisturbed escarpment outcrops located a few hundred meters west of the structure. With exception of a possible concave shatter cone found in the orthoquartzite of the central area, other diagnostic shock features are lacking. Some quartz-rich sandstones from the central area show pervasive fracturing of quartz grains with common concussion fractures. This deformation was followed by an event of quartz dissolution and calcite precipitation consistent with local sea- or groundwater heating. The combination of central stratigraphic uplift of 140 m, concussion features in discolored sandstone, outward-dipping concentric folds in the central area, deformation restricted to the rocks of the ring structure, a complex circular structure of 2.1 km diameter that appears broadly consistent with what one would expect from an impact structure in sedimentary targets, and a possible shatter cone all point to an impact origin of the Ash Shutbah structure. In fact, the Ash Shutbah structure appears to be a textbook example of an eroded, complex impact crater located in flat-lying sedimentary rocks, where the undisturbed stratigraphic section can be studied in escarpment outcrops in the vicinity of the structure.

Increasing the Extracted Beam Current Density in Ion Thrusters

NASA Astrophysics Data System (ADS)

Arthur, Neil Anderson

Ion thrusters have seen application on space science missions and numerous satellite missions. Ion engines offer higher electrical efficiency and specific impulse capability coupled with longer demonstrated lifetime as compared to other space propulsion technologies. However, ion engines are considered to have low thrust. This work aims to address the low thrust conception; whereby improving ion thruster performance and thrust density will lead to expanded mission capabilities for ion thruster technology. This goal poses a challenge because the mechanism for accelerating ions, the ion optics, is space charge limited according to the Child-Langmuir law-there is a finite number of ions that can be extracted through the grids for a given voltage. Currently, ion thrusters operate at only 40% of this limit, suggesting there is another limit artificially constraining beam current. Experimental evidence suggests the beam current can become source limited-the ion density within the plasma is not large enough to sustain high beam currents. Increasing the discharge current will increase ion density, but ring cusp ion engines become anode area limited at high discharge currents. The ring cusp magnetic field increases ionization efficiency but limits the anode area available for electron collection. Above a threshold current, the plasma becomes unstable. Increasing the engine size is one approach to increasing the operational discharge current, ion density, and thus the beam current, but this presents engineering challenges. The ion optics are a pair of closely spaced grids. As the engine diameter increases, it becomes difficult to maintain a constant grid gap. Span-to-gap considerations for high perveance optics limit ion engines to 50 cm in diameter. NASA designed the annular ion engine to address the anode area limit and scale-up problems by changing the discharge chamber geometry. The annular engine provides a central mounting structure for the optics, allowing the beam area to increase while maintaining a fixed span-to-gap. The central stalk also provides additional surface area for electron collection. Circumventing the anode area limitation, the annular ion engine can operate closer to the Child-Langmuir limit as compared to a conventional cylindrical ion thruster. Preliminary discharge characterization of a 65 cm annular ion engine shows >90% uniformity and validates the scalability of the technology. Operating beyond the Child-Langmuir limit would allow for even larger performance gains. This classic law does not consider the ion injection velocity into the grid sheath. The Child-Langmuir limit shifts towards higher current as the ion velocity increases. Ion drift velocity can be created by enhancing the axially-directed electric field. One method for creating this field is to modify the plasma potential distribution. This can be accomplished by biasing individual magnetic cusps, through isolated, conformal electrodes placed on each magnet ring. Experiments on a 15 cm ion thruster have shown that plasma potential in the bulk can be modified by as much as 5 V and establish ion drift towards the grid plane. Increases in ion current density at the grid by up to 20% are demonstrated. Performance implications are also considered, and increases in simulated beam current of 15% and decreases in discharge losses of 5% are observed. Electron density measurements within the magnetic cusps revealed, surprisingly, as cusp current draw increases, the leak width does not change. This suggests that instead of increasing the electron collection area, cusp bias enhances electron mobility along field lines.

Band structure engineering strategies of metal oxide semiconductor nanowires and related nanostructures: A review

NASA Astrophysics Data System (ADS)

Piyadasa, Adimali; Wang, Sibo; Gao, Pu-Xian

2017-07-01

The electronic band structure of a solid state semiconductor determines many of its physical and chemical characteristics such as electrical, optical, physicochemical, and catalytic activity. Alteration or modification of the band structure could lead to significant changes in these physical and chemical characteristics, therefore we introduce new mechanisms of creating novel solid state materials with interesting properties. Over the past three decades, research on band structure engineering has allowed development of various methods to modify the band structure of engineered materials. Compared to bulk counterparts, nanostructures generally exhibit higher band structure modulation capabilities due to the quantum confinement effect, prominent surface effect, and higher strain limit. In this review we will discuss various band structure engineering strategies in semiconductor nanowires and other related nanostructures, mostly focusing on metal oxide systems. Several important strategies of band structure modulation are discussed in detail, such as doping, alloying, straining, interface and core-shell nanostructuring.

Engineering: Defining and differentiating its unique culture

NASA Astrophysics Data System (ADS)

Pilotte, Mary K.

The world of work for engineering professionals is changing. At a rapid pace, experienced engineers are exiting the workforce due to retirement of the Baby Boomer generation, while at the same time the problems facing engineers are increasingly complex and frequently global in nature. For firms to protect their knowledge assets, they must ensure that acquired understandings are shared among their engineering work groups. Engineering teaching and learning in the workplace (i.e., knowledge sharing), is a social activity that resides in a social context governed by the professional engineering culture. This quantitative study uses Hofstede's Organizational Cultural Values Model (Hofstede, Neuijen, Ohayv, & Sanders, 1990) to examine dimensions of engineering culture in the workplace, producing a central tendency profile of engineering's cultural practices. Further, it explores through hypotheses if demographic differentiators, including birth generation, gender, race, industry sector of employment, and engineering discipline, play roles in forming engineering cultural practices. Results both corroborate aspects of Hofstede's model and assert new understandings relative to factors influencing dimensions of engineering practice. Outcomes are discussed in terms of their potential impact on industrial knowledge sharing and formation of beneficial engineering cultures.

Aircraft Engine Exhaust Nozzle System for Jet Noise Reduction

NASA Technical Reports Server (NTRS)

Thomas, Russell H. (Inventor); Czech, Michael J. (Inventor); Elkoby, Ronen (Inventor)

2014-01-01

The aircraft exhaust engine nozzle system includes a fan nozzle to receive a fan flow from a fan disposed adjacent to an engine disposed above an airframe surface of the aircraft, a core nozzle disposed within the fan nozzle and receiving an engine core flow, and a pylon structure connected to the core nozzle and structurally attached with the airframe surface to secure the engine to the aircraft.

The Structures of Centralized Governmental Privacy Protection: Approaches, Models, and Analysis.

ERIC Educational Resources Information Center

Jaeger, Paul T.; McClure, Charles R.; Fraser, Bruce T.

2002-01-01

Asserts that the federal government should adopt a centralized governmental structure for the privacy protection of personal information and data. Discusses the roles of federal law, federal agencies, and the judiciary; the concept of information privacy; the impact of current technologies; and models of centralized government structures for…

An economic analysis of adherence engineering to improve use of best practices during central line maintenance procedures.

PubMed

Nelson, Richard E; Angelovic, Aaron W; Nelson, Scott D; Gleed, Jeremy R; Drews, Frank A

2015-05-01

Adherence engineering applies human factors principles to examine non-adherence within a specific task and to guide the development of materials or equipment to increase protocol adherence and reduce human error. Central line maintenance (CLM) for intensive care unit (ICU) patients is a task through which error or non-adherence to protocols can cause central line-associated bloodstream infections (CLABSIs). We conducted an economic analysis of an adherence engineering CLM kit designed to improve the CLM task and reduce the risk of CLABSI. We constructed a Markov model to compare the cost-effectiveness of the CLM kit, which contains each of the 27 items necessary for performing the CLM procedure, compared with the standard care procedure for CLM, in which each item for dressing maintenance is gathered separately. We estimated the model using the cost of CLABSI overall ($45,685) as well as the excess LOS (6.9 excess ICU days, 3.5 excess general ward days). Assuming the CLM kit reduces the risk of CLABSI by 100% and 50%, this strategy was less costly (cost savings between $306 and $860) and more effective (between 0.05 and 0.13 more quality-adjusted life-years) compared with not using the pre-packaged kit. We identified threshold values for the effectiveness of the kit in reducing CLABSI for which the kit strategy was no longer less costly. An adherence engineering-based intervention to streamline the CLM process can improve patient outcomes and lower costs. Patient safety can be improved by adopting new approaches that are based on human factors principles.

Implementation of a Goal-Based Systems Engineering Process Using the Systems Modeling Language (SysML)

NASA Technical Reports Server (NTRS)

Patterson, Jonathan D.; Breckenridge, Jonathan T.; Johnson, Stephen B.

2013-01-01

Building upon the purpose, theoretical approach, and use of a Goal-Function Tree (GFT) being presented by Dr. Stephen B. Johnson, described in a related Infotech 2013 ISHM abstract titled "Goal-Function Tree Modeling for Systems Engineering and Fault Management", this paper will describe the core framework used to implement the GFTbased systems engineering process using the Systems Modeling Language (SysML). These two papers are ideally accepted and presented together in the same Infotech session. Statement of problem: SysML, as a tool, is currently not capable of implementing the theoretical approach described within the "Goal-Function Tree Modeling for Systems Engineering and Fault Management" paper cited above. More generally, SysML's current capabilities to model functional decompositions in the rigorous manner required in the GFT approach are limited. The GFT is a new Model-Based Systems Engineering (MBSE) approach to the development of goals and requirements, functions, and its linkage to design. As a growing standard for systems engineering, it is important to develop methods to implement GFT in SysML. Proposed Method of Solution: Many of the central concepts of the SysML language are needed to implement a GFT for large complex systems. In the implementation of those central concepts, the following will be described in detail: changes to the nominal SysML process, model view definitions and examples, diagram definitions and examples, and detailed SysML construct and stereotype definitions.

Conceptional Considerations to Energy Balance and Global Warming Potential of Soil Bioengineering Structures

NASA Astrophysics Data System (ADS)

von der Thannen, Magdalena; Paratscha, Roman; Smutny, Roman; Lampalzer, Thomas; Strauss, Alfred; Rauch, Hans Peter

2016-04-01

Nowadays there is a high demand on engineering solutions considering not only technical aspects but also ecological and aesthetic values. In this context soil bioengineering techniques are often used as standalone solutions or in combination with conventional engineering structures. It is a construction technique that uses biological components for hydraulic and civil engineering solutions. In general it pursues the same objectives as conventional civil engineering structures. Currently the used assessment methods for soil bioengineering structures are referencing technically, ecologically and socio-economically. In a modern engineering approach additionally, environmental impacts and potential added values should be considered. The research project E-Protect aims at developing Environmental Life Cycle Assessment (LCA) models for this special field of alpine protective constructions. Both, the Cumulative Energy Demand (CED) and the Global Warming Potential (GWP) should be considered in an Environmental LCA over the whole life cycle of an engineering structure. The life cycle itself can be divided into three phases: the construction phase, the use phase and the end of life phase. The paper represents a concept to apply an Environmental LCA model for soil bioengineering structures. Beside the construction phase of these structures particular attention will be given to the use phase. It is not only important in terms of engineering effects but also plays an important role for positive carbon footprint due to the growing plants of soil bioengineering structures in contrast to conventional structures. Innovative Environmental LCA models will be applied to soil bioengineering structures which provide a new transparency for the responsible planners and stakeholders, by pointing out the total consumption of resources in all construction phases and components.

Orbiting Water Molecules Dance to Tune Of Galaxy's "Central Engine," Astronomers Say

NASA Astrophysics Data System (ADS)

2000-01-01

A disk of water molecules orbiting a supermassive black hole at the core of a galaxy 60 million light-years away is "reverberating" in response to variations in the energy output from the galaxy's powerful "central engine" close to the black hole, astronomers say. The team of astronomers used the National Science Foundation's (NSF) Very Large Array (VLA) radio telescope in New Mexico and the 100-meter-diameter radio telescope of the Max Planck Institute for Radio Astronomy at Effelsberg, Germany, to observe the galaxy NGC 1068 in the constellation Cetus. They announced their findings today at the American Astronomical Society's meeting in Atlanta. The water molecules, in a disk some 5 light-years in diameter, are acting as a set of giant cosmic radio-wave amplifiers, called masers. Using energy radiated by the galaxy's "central engine," the molecules strengthen, or brighten, radio emission at a particular frequency as seen from Earth. "We have seen variations in the radio 'brightness' of these cosmic amplifiers that we believe were caused by variations in the energy output of the central engine," said Jack Gallimore, an astronomer at the National Radio Astronomy Observatory (NRAO) in Charlottesville, VA. "This could provide us with a valuable new tool for learning about the central engine itself," he added. Gallimore worked with Stefi Baum of the Space Telescope Science Institute in Baltimore, MD; Christian Henkel of the Max Planck Institute for Radio Astronomy in Bonn, Germany; Ian Glass of the South African Astronomical Observatory; Mark Claussen of the NRAO in Socorro, NM; and Almudena Prieto of the European Southern Observatory in Munich, Germany. "Our observations show that NGC 1068 is the second-known case of a giant disk of water molecules orbiting a supermassive black hole at a galaxy's core," Gallimore said. The first case was the galaxy NGC 4258 (Messier 106), whose disk of radio-amplifying water molecules was measured by the NSF's Very Long Baseline Array (VLBA) radio telescope in 1995. Further VLBA observations of NGC 4258 allowed astronomers to calculate an extremely accurate distance to that galaxy last year. "We're excited to find this phenomenon in a second galaxy, but we're also tantalized by the evidence that these masers respond to variations of the central engine," Gallimore said. In order to amplify radio signals, masers, like their visible-light counterparts, lasers, require a source of energy, called the pumping energy. The scientists believe the masers in NGC 1068 get that pumping energy from a highly-energetic, superhot disk of material that is being pulled into the black hole. That disk, called an accretion disk, emits X-rays that the astronomers think start a chain of events that powers the masers. Such accretion disks can be unstable, dramatically changing their energy output from time to time. "When the accretion disk puts out more energy, the masers should brighten, and when it puts out less energy, they should get fainter. If the accretion disk gets too bright, however, water molecules are destroyed and the masers turn off. We think that's what we're seeing in this galaxy," Gallimore said. "We want to watch this in the future to learn more, not only about the masers, but also about the accretion disk itself," he said. The strongest evidence that the masers are responding to variations in the output of the central engine came from watching variations in the brightness of masers on opposite sides of the water molecule disk. The masers on both sides of the molecular disk, some 5 light-years across, brightened within about two weeks of each other. "If this were caused by something within that molecular disk itself, it would take about 10,000 years to affect both sides of the disk, because of the orbital times involved. However, both sides of the disk are the same distance from the central engine, so they can both respond to the central engine simultaneously," Gallimore explained. The black hole at NGC 1068's center, the scientists say, is about 10 million times more massive than the Sun. NGC 1068 also is known as Messier 77 (M77), one of the objects listed in French astronomer Charles Messier's catalog of non-stellar objects. First observed in 1780, it appeared in the version of Messier's catalog published in 1781. In 1914, Lowell Observatory astronomer Vesto Slipher measured the Doppler shift in the galaxy's light, showing that the galaxy is receding from Earth at a speed of about 1,100 kilometers per second. The galaxy's water masers, which amplify radio signals at a frequency of 22 GHz, were discovered in 1984. The galaxy is visible in moderate-sized amateur telescopes. The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.

A Case Study of an Experiment Using Streaming of Lectures in Teaching Engineering Mathematics

ERIC Educational Resources Information Center

Fredriksen, Helge

2015-01-01

To support the possibility of taking an online engineering degree programme, Narvik University College has chosen to facilitate a streaming service of all lectures conducted by the college. At the Bodø college campus, in the academic year of 2012/2013, these online lectures were used as a central component in a didactic innovation project. The aim…

Development of a spinning wave heat engine

NASA Technical Reports Server (NTRS)

Zinn, B. T.; Powell, E. A.; Hubbartt, J. E.

1982-01-01

A theoretical analysis and an experimental investigation were conducted to assess the feasibility of developing a spinning wave heat engine. Such as engine would utilize a large amplitude traveling acoustic wave rotating around a cylindrica chamber, and it should not suffer from the inefficiency, noise, and intermittent thrust which characterizes pulse jet engines. The objective of this investigation was to determine whether an artificially driven large amplitude spinning transverse wave could induce a steady flow of air through the combustion chamber under cold flow conditions. In the theoretical analysis the Maslen and Moore perturbation technique was extended to study flat cylinders (pancake geometry) with completely open side walls and a central opening. In the parallel experimental study, a test moel was used to determine resonant frequencies and radial pressure distributions, as well as oscillatory and steady flow velocities at the inner and outer peripheries. The experimental frequency was nearly the same as the theoretical acoustic value for a model of the same outer diameter but without a central hole. Although the theoretical analysis did not predict a steady velocity component, simulaneous measurements of hotwire and microphone responses have shown that the spinning wave pumps a mean flow radially outward through the cavity.

Collapsar γ-ray bursts: how the luminosity function dictates the duration distribution

NASA Astrophysics Data System (ADS)

Petropoulou, Maria; Barniol Duran, Rodolfo; Giannios, Dimitrios

2017-12-01

Jets in long-duration γ-ray bursts (GRBs) have to drill through the collapsing star in order to break out of it and produce the γ-ray signal while the central engine is still active. If the breakout time is shorter for more powerful engines, then the jet-collapsar interaction acts as a filter of less luminous jets. We show that the observed broken power-law GRB luminosity function is a natural outcome of this process. For a theoretically motivated breakout time that scales with jet luminosity as L-χ with χ ∼ 1/3-1/2, we show that the shape of the γ-ray duration distribution can be uniquely determined by the GRB luminosity function and matches the observed one. This analysis has also interesting implications about the supernova-central engine connection. We show that not only successful jets can deposit sufficient energy in the stellar envelope to power the GRB-associated supernovae, but also failed jets may operate in all Type Ib/c supernovae.

RECONSTRUCTING THREE-DIMENSIONAL JET GEOMETRY FROM TWO-DIMENSIONAL IMAGES

NASA Astrophysics Data System (ADS)

Avachat, Sayali; Perlman, Eric S.; Li, Kunyang; Kosak, Katie

2018-01-01

Relativistic jets in AGN are one of the most interesting and complex structures in the Universe. Some of the jets can be spread over hundreds of kilo parsecs from the central engine and display various bends, knots and hotspots. Observations of the jets can prove helpful in understanding the emission and particle acceleration processes from sub-arcsec to kilo parsec scales and the role of magnetic field in it. The M87 jet has many bright knots as well as regions of small and large bends. We attempt to model the jet geometry using the observed 2 dimensional structure. The radio and optical images of the jet show evidence of presence of helical magnetic field throughout. Using the observed structure in the sky frame, our goal is to gain an insight into the intrinsic 3 dimensional geometry in the jets frame. The structure of the bends in jet's frame may be quite different than what we see in the sky frame. The knowledge of the intrinsic structure will be helpful in understanding the appearance of the magnetic field and hence polarization morphology. To achieve this, we are using numerical methods to solve the non-linear equations based on the jet geometry. We are using the Log Likelihood method and algorithm based on Markov Chain Monte Carlo (MCMC) simulations.

Optimizing Dynamical Network Structure for Pinning Control

NASA Astrophysics Data System (ADS)

Orouskhani, Yasin; Jalili, Mahdi; Yu, Xinghuo

2016-04-01

Controlling dynamics of a network from any initial state to a final desired state has many applications in different disciplines from engineering to biology and social sciences. In this work, we optimize the network structure for pinning control. The problem is formulated as four optimization tasks: i) optimizing the locations of driver nodes, ii) optimizing the feedback gains, iii) optimizing simultaneously the locations of driver nodes and feedback gains, and iv) optimizing the connection weights. A newly developed population-based optimization technique (cat swarm optimization) is used as the optimization method. In order to verify the methods, we use both real-world networks, and model scale-free and small-world networks. Extensive simulation results show that the optimal placement of driver nodes significantly outperforms heuristic methods including placing drivers based on various centrality measures (degree, betweenness, closeness and clustering coefficient). The pinning controllability is further improved by optimizing the feedback gains. We also show that one can significantly improve the controllability by optimizing the connection weights.

Twelve years in offshore for Doris C. G

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1979-04-12

The offshore engineering operations of Doris have included the design of concrete and steel offshore structures, the design and construction of diving and underwater equipment, offshore equipment, vessels, and heavy mooring systems, and the design and installation of pipelines and risers. The company has also engaged in pipelaying, marine operations, diving, and inspection and maintenance work. Some achievements in 1978 were the completion, tow-out, and installation of the Ninian central platform and the design of an additional riser for the Frigg field manifold compression platform to connect the Piper field to the Frigg gas pipeline. The articulated gravity tower formore » concrete platforms was certified by Norsk Veritas in 1978, but fatigue tests on the articulating ball joint are continuing. New designs include the fixed gravity structure with removable floats, which makes the substructure much smaller, so that concrete platforms become economically feasible in water depths previously considered prohibitive, and the steel-and-concrete hybrid platform, which has been fully developed and certified as safe and economical.« less

Reliability assessment of slender concrete columns at the stability failure

NASA Astrophysics Data System (ADS)

Valašík, Adrián; Benko, Vladimír; Strauss, Alfred; Täubling, Benjamin

2018-01-01

The European Standard for designing concrete columns within the use of non-linear methods shows deficiencies in terms of global reliability, in case that the concrete columns fail by the loss of stability. The buckling failure is a brittle failure which occurs without warning and the probability of its formation depends on the columns slenderness. Experiments with slender concrete columns were carried out in cooperation with STRABAG Bratislava LTD in Central Laboratory of Faculty of Civil Engineering SUT in Bratislava. The following article aims to compare the global reliability of slender concrete columns with slenderness of 90 and higher. The columns were designed according to methods offered by EN 1992-1-1 [1]. The mentioned experiments were used as basis for deterministic nonlinear modelling of the columns and subsequent the probabilistic evaluation of structural response variability. Final results may be utilized as thresholds for loading of produced structural elements and they aim to present probabilistic design as less conservative compared to classic partial safety factor based design and alternative ECOV method.

Maltose conjugation to PCL: Advanced structural characterization and preliminary biological properties

NASA Astrophysics Data System (ADS)

Secchi, Valeria; Guizzardi, Roberto; Russo, Laura; Pastori, Valentina; Lecchi, Marzia; Franchi, Stefano; Iucci, Giovanna; Battocchio, Chiara; Cipolla, Laura

2018-05-01

The emerging trends in regenerative medicine rely among others on biomaterial-based therapies, with the use of biomaterials as a central delivery system for biochemical and physical cues to manipulate transplanted or ingrowth cells and to orchestrate tissue regeneration. Cell adhesion properties of a biomaterial strongly depend on its surface characteristics. Among others poly(ε-caprolactone) (PCL) is a biocompatible and biodegradable material with low cytotoxicity that is widely adopted as synthetic polymer in several applications. However, it is hydrophobic, which limits its use in tissue engineering. In order to improve its hydrophilicity and cellular compatibility, PCL surface was grafted with maltose through a two-step procedure in which controlled aminolysis of PCL ester bonds by hexanediamine was followed by reductive amination with the carbohydrate reducing end. The modified PCL surface was then characterized in detail by x-ray Photoelectron Spectroscopy (XPS) and Near Edge x-ray Absorption Fine Structure (NEXAFS) spectroscopies. In addition, the biocompatibility of the proposed biomaterial was investigated in preliminary biological assays.

Data management in engineering

NASA Technical Reports Server (NTRS)

Browne, J. C.

1976-01-01

An introduction to computer based data management is presented with an orientation toward the needs of engineering application. The characteristics and structure of data management systems are discussed. A link to familiar engineering applications of computing is established through a discussion of data structure and data access procedures. An example data management system for a hypothetical engineering application is presented.

10. Photocopy of drawing, February 1958, NUCLEAR REACTOR FACILITY, STRUCTURAL ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

10. Photocopy of drawing, February 1958, NUCLEAR REACTOR FACILITY, STRUCTURAL CROSS SECTION. Giffals & Vallet, Inc., L. Rosetti, Associated Architects and Engineers, Detroit, Michigan; and U.S. Army Engineer Division, New England Corps of Engineers, Boston, Massachusetts. Drawing Number 35-84-04. (Original: AMTL Engineering Division, Watertown). - Watertown Arsenal, Building No. 100, Wooley Avenue, Watertown, Middlesex County, MA

Numerical evaluation of single central jet for turbine disk cooling

NASA Astrophysics Data System (ADS)

Subbaraman, M. R.; Hadid, A. H.; McConnaughey, P. K.

The cooling arrangement of the Space Shuttle Main Engine High Pressure Oxidizer Turbopump (HPOTP) incorporates two jet rings, each of which produces 19 high-velocity coolant jets. At some operating conditions, the frequency of excitation associated with the 19 jets coincides with the natural frequency of the turbine blades, contributing to fatigue cracking of blade shanks. In this paper, an alternate turbine disk cooling arrangement, applicable to disk faces of zero hub radius, is evaluated, which consists of a single coolant jet impinging at the center of the turbine disk. Results of the CFD analysis show that replacing the jet ring with a single central coolant jet in the HPOTP leads to an acceptable thermal environment at the disk rim. Based on the predictions of flow and temperature fields for operating conditions, the single central jet cooling system was recommended for implementation into the development program of the Technology Test Bed Engine at NASA Marshall Space Flight Center.

Thermal barrier coatings for gas-turbine engine applications.

PubMed

Padture, Nitin P; Gell, Maurice; Jordan, Eric H

2002-04-12

Hundreds of different types of coatings are used to protect a variety of structural engineering materials from corrosion, wear, and erosion, and to provide lubrication and thermal insulation. Of all these, thermal barrier coatings (TBCs) have the most complex structure and must operate in the most demanding high-temperature environment of aircraft and industrial gas-turbine engines. TBCs, which comprise metal and ceramic multilayers, insulate turbine and combustor engine components from the hot gas stream, and improve the durability and energy efficiency of these engines. Improvements in TBCs will require a better understanding of the complex changes in their structure and properties that occur under operating conditions that lead to their failure. The structure, properties, and failure mechanisms of TBCs are herein reviewed, together with a discussion of current limitations and future opportunities.

Functionalized carbon nanotubes for potential medicinal applications.

PubMed

Zhang, Yi; Bai, Yuhong; Yan, Bing

2010-06-01

Functionalized carbon nanotubes display unique properties that enable a variety of medicinal applications, including the diagnosis and treatment of cancer, infectious diseases and central nervous system disorders, and applications in tissue engineering. These potential applications are particularly encouraged by their ability to penetrate biological membranes and relatively low toxicity. High aspect ratio, unique optical property and the likeness as small molecule make carbon nanotubes an unusual allotrope of element carbon. After functionalization, carbon nanotubes display potentials for a variety of medicinal applications, including the diagnosis and treatment of cancer, infectious diseases and central nervous system disorders, and applications in tissue engineering. These potential applications are particularly encouraged by their ability to penetrate biological membranes and relatively low toxicity. (c) 2010 Elsevier Ltd. All rights reserved.

Slow wave structures using twisted waveguides for charged particle applications

DOEpatents

Kang, Yoon W.; Fathy, Aly E.; Wilson, Joshua L.

2012-12-11

A rapidly twisted electromagnetic accelerating structure includes a waveguide body having a central axis, one or more helical channels defined by the body and disposed around a substantially linear central axial channel, with central portions of the helical channels merging with the linear central axial channel. The structure propagates electromagnetic waves in the helical channels which support particle beam acceleration in the central axial channel at a phase velocity equal to or slower than the speed of light in free space. Since there is no variation in the shape of the transversal cross-section along the axis of the structure, inexpensive mechanical fabrication processes can be used to form the structure, such as extrusion, casting or injection molding. Also, because the field and frequency of the resonant mode depend on the whole structure rather than on dimensional tolerances of individual cells, no tuning of individual cells is needed. Accordingly, the overall operating frequency may be varied with a tuning/phase shifting device located outside the resonant waveguide structure.

Household Structure and Suburbia Residence in U.S. Metropolitan Areas: Evidence from the American Housing Survey.

PubMed

Jung, Gowoon; Yang, Tse-Chuan

2016-01-01

Suburbs have demographically diversified in terms of race, yet little research has been done on household structures in suburbs. Using the 2011 American Housing Survey and 2009-2013 American Community Survey, this study investigates the distributions of household structures in suburbia and central cities, and the relationship between household structures and residential attainment. The findings of this research include: (1) The distribution of household structures differs between suburbia and central cities. Married-couple households are the most common household type in both central cities and suburbs, but they are more likely to reside in suburbia than in central cities; (2) Household structure is a determinant of residential attainment and the relationship varies by race/ethnicity groups. Among Hispanics and Asians, multigenerational household structure is indicative of central city residence, but this association does not hold for whites and blacks. For multigenerational households, the odds of living in suburbia decreases by almost 40 percent among Hispanics and by almost 50 percent for Asians.

Household Structure and Suburbia Residence in U.S. Metropolitan Areas: Evidence from the American Housing Survey

PubMed Central

Jung, Gowoon; Yang, Tse-Chuan

2016-01-01

Suburbs have demographically diversified in terms of race, yet little research has been done on household structures in suburbs. Using the 2011 American Housing Survey and 2009–2013 American Community Survey, this study investigates the distributions of household structures in suburbia and central cities, and the relationship between household structures and residential attainment. The findings of this research include: (1) The distribution of household structures differs between suburbia and central cities. Married-couple households are the most common household type in both central cities and suburbs, but they are more likely to reside in suburbia than in central cities; (2) Household structure is a determinant of residential attainment and the relationship varies by race/ethnicity groups. Among Hispanics and Asians, multigenerational household structure is indicative of central city residence, but this association does not hold for whites and blacks. For multigenerational households, the odds of living in suburbia decreases by almost 40 percent among Hispanics and by almost 50 percent for Asians. PMID:27917300

A Paperless Course on Structural Engineering Programming: Investing in Educational Technology in the Times of the Greek Financial Recession

ERIC Educational Resources Information Center

Sextos, Anastasios G.

2014-01-01

This paper presents the structure of an undergraduate course entitled "programming techniques and the use of specialised software in structural engineering" which is offered to the fifth (final) year students of the Civil Engineering Department of Aristotle University Thessaloniki in Greece. The aim of this course is to demonstrate the…

Improved structural integrity through advances in reliable residual stress measurement: the impact of ENGIN-X

NASA Astrophysics Data System (ADS)

Edwards, L.; Santisteban, J. R.

The determination of accurate reliable residual stresses is critical to many fields of structural integrity. Neutron stress measurement is a non-destructive technique that uniquely provides insights into stress fields deep within engineering components and structures. As such, it has become an increasingly important tool within engineering, leading to improved manufacturing processes to reduce stress and distortion as well as to the definition of more precise lifing procedures. This paper describes the likely impact of the next generation of dedicated engineering stress diffractometers currently being constructed and the utility of the technique using examples of residual stresses both beneficial and detrimental to structural integrity.

Automating gene library synthesis by structure-based combinatorial protein engineering: examples from plant sesquiterpene synthases.

PubMed

Dokarry, Melissa; Laurendon, Caroline; O'Maille, Paul E

2012-01-01

Structure-based combinatorial protein engineering (SCOPE) is a homology-independent recombination method to create multiple crossover gene libraries by assembling defined combinations of structural elements ranging from single mutations to domains of protein structure. SCOPE was originally inspired by DNA shuffling, which mimics recombination during meiosis, where mutations from parental genes are "shuffled" to create novel combinations in the resulting progeny. DNA shuffling utilizes sequence identity between parental genes to mediate template-switching events (the annealing and extension of one parental gene fragment on another) in PCR reassembly reactions to generate crossovers and hence recombination between parental genes. In light of the conservation of protein structure and degeneracy of sequence, SCOPE was developed to enable the "shuffling" of distantly related genes with no requirement for sequence identity. The central principle involves the use of oligonucleotides to encode for crossover regions to choreograph template-switching events during PCR assembly of gene fragments to create chimeric genes. This approach was initially developed to create libraries of hybrid DNA polymerases from distantly related parents, and later developed to create a combinatorial mutant library of sesquiterpene synthases to explore the catalytic landscapes underlying the functional divergence of related enzymes. This chapter presents a simplified protocol of SCOPE that can be integrated with different mutagenesis techniques and is suitable for automation by liquid-handling robots. Two examples are presented to illustrate the application of SCOPE to create gene libraries using plant sesquiterpene synthases as the model system. In the first example, we outline how to create an active-site library as a series of complex mixtures of diverse mutants. In the second example, we outline how to create a focused library as an array of individual clones to distil minimal combinations of functionally important mutations. Through these examples, the principles of the technique are illustrated and the suitability of automating various aspects of the procedure for given applications are discussed. Copyright © 2012 Elsevier Inc. All rights reserved.

Distributed Control Architecture for Gas Turbine Engine. Chapter 4

NASA Technical Reports Server (NTRS)

Culley, Dennis; Garg, Sanjay

2009-01-01

The transformation of engine control systems from centralized to distributed architecture is both necessary and enabling for future aeropropulsion applications. The continued growth of adaptive control applications and the trend to smaller, light weight cores is a counter influence on the weight and volume of control system hardware. A distributed engine control system using high temperature electronics and open systems communications will reverse the growing trend of control system weight ratio to total engine weight and also be a major factor in decreasing overall cost of ownership for aeropropulsion systems. The implementation of distributed engine control is not without significant challenges. There are the needs for high temperature electronics, development of simple, robust communications, and power supply for the on-board electronics.

Lewis Structures Technology, 1988. Volume 3: Structural Integrity Fatigue and Fracture Wind Turbines HOST

NASA Technical Reports Server (NTRS)

1988-01-01

The charter of the Structures Division is to perform and disseminate results of research conducted in support of aerospace engine structures. These results have a wide range of applicability to practioners of structural engineering mechanics beyond the aerospace arena. The specific purpose of the symposium was to familiarize the engineering structures community with the depth and range of research performed by the division and its academic and industrial partners. Sessions covered vibration control, fracture mechanics, ceramic component reliability, parallel computing, nondestructive evaluation, constitutive models and experimental capabilities, dynamic systems, fatigue and damage, wind turbines, hot section technology (HOST), aeroelasticity, structural mechanics codes, computational methods for dynamics, structural optimization, and applications of structural dynamics, and structural mechanics computer codes.

Pavement-Transportation Computer Assisted Structural Engineering (PCASE) Implementation of the Modified Berggren (ModBerg) Equation for Computing the Frost Penetration Depth within Pavement Structures

DTIC Science & Technology

2012-04-01

ER D C/ G SL T R -1 2 -1 5 Pavement -Transportation Computer Assisted Structural Engineering (PCASE) Implementation of the Modified...Berggren (ModBerg) Equation for Computing the Frost Penetration Depth within Pavement Structures G eo te ch n ic al a n d S tr u ct u re s La b or at...April 2012 Pavement -Transportation Computer Assisted Structural Engineering (PCASE) Implementation of the Modified Berggren (ModBerg) Equation for

Cell–scaffold interaction within engineered tissue

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Haiping; Liu, Yuanyuan, E-mail: Yuanyuan_liu@shu.edu.cn; Jiang, Zhenglong

The structure of a tissue engineering scaffold plays an important role in modulating tissue growth. A novel gelatin–chitosan (Gel–Cs) scaffold with a unique structure produced by three-dimensional printing (3DP) technology combining with vacuum freeze-drying has been developed for tissue-engineering applications. The scaffold composed of overall construction, micro-pore, surface morphology, and effective mechanical property. Such a structure meets the essential design criteria of an ideal engineered scaffold. The favorable cell–matrix interaction supports the active biocompatibility of the structure. The structure is capable of supporting cell attachment and proliferation. Cells seeded into this structure tend to maintain phenotypic shape and secreted largemore » amounts of extracellular matrix (ECM) and the cell growth decreased the mechanical properties of scaffold. This novel biodegradable scaffold has potential applications for tissue engineering based upon its unique structure, which acts to support cell growth. - Highlights: • The scaffold is not only for providing a surface for cell residence but also for determining cell phenotype and retaining structural integrity. • The mechanical property of scaffold can be affected by activities of cell. • The scaffold provides a microenvironment for cell attachment, growth, and migration.« less

The necessity of a theory of biology for tissue engineering: metabolism-repair systems.

PubMed

Ganguli, Suman; Hunt, C Anthony

2004-01-01

Since there is no widely accepted global theory of biology, tissue engineering and bioengineering lack a theoretical understanding of the systems being engineered. By default, tissue engineering operates with a "reductionist" theoretical approach, inherited from traditional engineering of non-living materials. Long term, that approach is inadequate, since it ignores essential aspects of biology. Metabolism-repair systems are a theoretical framework which explicitly represents two "functional" aspects of living organisms: self-repair and self-replication. Since repair and replication are central to tissue engineering, we advance metabolism-repair systems as a potential theoretical framework for tissue engineering. We present an overview of the framework, and indicate directions to pursue for extending it to the context of tissue engineering. We focus on biological networks, both metabolic and cellular, as one such direction. The construction of these networks, in turn, depends on biological protocols. Together these concepts may help point the way to a global theory of biology appropriate for tissue engineering.

DRUMS: a human disease related unique gene mutation search engine.

PubMed

Li, Zuofeng; Liu, Xingnan; Wen, Jingran; Xu, Ye; Zhao, Xin; Li, Xuan; Liu, Lei; Zhang, Xiaoyan

2011-10-01

With the completion of the human genome project and the development of new methods for gene variant detection, the integration of mutation data and its phenotypic consequences has become more important than ever. Among all available resources, locus-specific databases (LSDBs) curate one or more specific genes' mutation data along with high-quality phenotypes. Although some genotype-phenotype data from LSDB have been integrated into central databases little effort has been made to integrate all these data by a search engine approach. In this work, we have developed disease related unique gene mutation search engine (DRUMS), a search engine for human disease related unique gene mutation as a convenient tool for biologists or physicians to retrieve gene variant and related phenotype information. Gene variant and phenotype information were stored in a gene-centred relational database. Moreover, the relationships between mutations and diseases were indexed by the uniform resource identifier from LSDB, or another central database. By querying DRUMS, users can access the most popular mutation databases under one interface. DRUMS could be treated as a domain specific search engine. By using web crawling, indexing, and searching technologies, it provides a competitively efficient interface for searching and retrieving mutation data and their relationships to diseases. The present system is freely accessible at http://www.scbit.org/glif/new/drums/index.html. © 2011 Wiley-Liss, Inc.

Wireless and real-time structural damage detection: A novel decentralized method for wireless sensor networks

NASA Astrophysics Data System (ADS)

Avci, Onur; Abdeljaber, Osama; Kiranyaz, Serkan; Hussein, Mohammed; Inman, Daniel J.

2018-06-01

Being an alternative to conventional wired sensors, wireless sensor networks (WSNs) are extensively used in Structural Health Monitoring (SHM) applications. Most of the Structural Damage Detection (SDD) approaches available in the SHM literature are centralized as they require transferring data from all sensors within the network to a single processing unit to evaluate the structural condition. These methods are found predominantly feasible for wired SHM systems; however, transmission and synchronization of huge data sets in WSNs has been found to be arduous. As such, the application of centralized methods with WSNs has been a challenge for engineers. In this paper, the authors are presenting a novel application of 1D Convolutional Neural Networks (1D CNNs) on WSNs for SDD purposes. The SDD is successfully performed completely wireless and real-time under ambient conditions. As a result of this, a decentralized damage detection method suitable for wireless SHM systems is proposed. The proposed method is based on 1D CNNs and it involves training an individual 1D CNN for each wireless sensor in the network in a format where each CNN is assigned to process the locally-available data only, eliminating the need for data transmission and synchronization. The proposed damage detection method operates directly on the raw ambient vibration condition signals without any filtering or preprocessing. Moreover, the proposed approach requires minimal computational time and power since 1D CNNs merge both feature extraction and classification tasks into a single learning block. This ability is prevailingly cost-effective and evidently practical in WSNs considering the hardware systems have been occasionally reported to suffer from limited power supply in these networks. To display the capability and verify the success of the proposed method, large-scale experiments conducted on a laboratory structure equipped with a state-of-the-art WSN are reported.

Virtual engine management simulator for educational purposes

NASA Astrophysics Data System (ADS)

Drosescu, R.

2017-10-01

This simulator was conceived as a software program capable of generating complex control signals, identical to those in the electronic management systems of modern spark ignition or diesel engines. Speed in rpm and engine load percentage defined by throttle opening angle represent the input variables in the simulation program and are graphically entered by two-meter instruments from the simulator central block diagram. The output signals are divided into four categories: synchronization and position of each cylinder, spark pulses for spark ignition engines, injection pulses and, signals for generating the knock window for each cylinder in the case of a spark ignition engine. The simulation program runs in real-time so each signal evolution reflects the real behavior on a physically thermal engine. In this way, the generated signals (ignition or injection pulses) can be used with additionally drivers to control an engine on the test bench.

Performance of a High-Speed Compression-Ignition Engine Using Multiple Orifice Fuel Injection Nozzles

NASA Technical Reports Server (NTRS)

Spanogle, J A; Foster, H H

1930-01-01

This report presents test results obtained at the Langley Memorial Aeronautical Laboratory of the National Advisory Committee for Aeronautics during an investigation to determine the relative performance of a single-cylinder, high-speed, compression-ignition engine when using fuel injection valve nozzles with different numbers, sizes, and directions of round orifices. A spring-loaded, automatic injection valve was used, centrally located at the top of a vertical disk-type combustion chamber formed between horizontally opposed inlet and exhaust valves of a 5 inch by 7 inch engine.

Engine System Loads Analysis Compared to Hot-Fire Data

NASA Technical Reports Server (NTRS)

Frady, Gregory P.; Jennings, John M.; Mims, Katherine; Brunty, Joseph; Christensen, Eric R.; McConnaughey, Paul R. (Technical Monitor)

2002-01-01

Early implementation of structural dynamics finite element analyses for calculation of design loads is considered common design practice for high volume manufacturing industries such as automotive and aeronautical industries. However with the rarity of rocket engine development programs starts, these tools are relatively new to the design of rocket engines. In the NASA MC-1 engine program, the focus was to reduce the cost-to-weight ratio. The techniques for structural dynamics analysis practices, were tailored in this program to meet both production and structural design goals. Perturbation of rocket engine design parameters resulted in a number of MC-1 load cycles necessary to characterize the impact due to mass and stiffness changes. Evolution of loads and load extraction methodologies, parametric considerations and a discussion of load path sensitivities are important during the design and integration of a new engine system. During the final stages of development, it is important to verify the results of an engine system model to determine the validity of the results. During the final stages of the MC-1 program, hot-fire test results were obtained and compared to the structural design loads calculated by the engine system model. These comparisons are presented in this paper.

Detailed Post-Soft Impact Progressive Damage Assessment for Hybrid Structure Jet Engines

NASA Technical Reports Server (NTRS)

Siddens, Aaron; Bayandor, Javid; Celestina, Mark L.

2014-01-01

Currently, certification of engine designs for resistance to bird strike is reliant on physical tests. Predictive modeling of engine structural damage has mostly been limited to evaluation of individual forward section components, such as fan blades within a fixed frame of reference, to direct impact with a bird. Such models must be extended to include interactions among engine components under operating conditions to evaluate the full extent of engine damage. This paper presents the results of a study aim to develop a methodology for evaluating bird strike damage in advanced propulsion systems incorporating hybrid composite/metal structures. The initial degradation and failure of individual fan blades struck by a bird were investigated. Subsequent damage to other fan blades and engine components due to resultant violent fan assembly vibrations and fragmentation was further evaluated. Various modeling parameters for the bird and engine components were investigated to determine guidelines for accurately capturing initial damage and progressive failure of engine components. Then, a novel hybrid structure modeling approach was investigated and incorporated into the crashworthiness methodology. Such a tool is invaluable to the process of design, development, and certification of future advanced propulsion systems.

Engineering nonspherical hollow structures with complex interiors by template-engaged redox etching.

PubMed

Wang, Zhiyu; Luan, Deyan; Li, Chang Ming; Su, Fabing; Madhavi, Srinivasan; Boey, Freddy Yin Chiang; Lou, Xiong Wen

2010-11-17

Despite the significant advancement in making hollow structures, one unsolved challenge in the field is how to engineer hollow structures with specific shapes, tunable compositions, and desirable interior structures. In particular, top-down engineering the interiors inside preformed hollow structures is still a daunting task. In this work, we demonstrate a facile approach for the preparation of a variety of uniform hollow structures, including Cu(2)O@Fe(OH)(x) nanorattles and Fe(OH)(x) cages with various shapes and dimensions by template-engaged redox etching of shape-controlled Cu(2)O crystals. The composition can be readily modulated at different structural levels to generate other interesting structures such as Cu(2)O@Fe(2)O(3) and Cu@Fe(3)O(4) rattles, as well as Fe(2)O(3) and Fe(3)O(4) cages. More remarkably, this strategy enables top-down engineering the interiors of hollow structures as demonstrated by the fabrication of double-walled nanorattles and nanoboxes, and even box-in-box structures. In addition, this approach is also applied to form Au and MnO(x) based hollow structures.

Interfacing with the nervous system: a review of current bioelectric technologies.

PubMed

Sahyouni, Ronald; Mahmoodi, Amin; Chen, Jefferson W; Chang, David T; Moshtaghi, Omid; Djalilian, Hamid R; Lin, Harrison W

2017-10-23

The aim of this study is to discuss the state of the art with regard to established or promising bioelectric therapies meant to alter or control neurologic function. We present recent reports on bioelectric technologies that interface with the nervous system at three potential sites-(1) the end organ, (2) the peripheral nervous system, and (3) the central nervous system-while exploring practical and clinical considerations. A literature search was executed on PubMed, IEEE, and Web of Science databases. A review of the current literature was conducted to examine functional and histomorphological effects of neuroprosthetic interfaces with a focus on end-organ, peripheral, and central nervous system interfaces. Innovations in bioelectric technologies are providing increasing selectivity in stimulating distinct nerve fiber populations in order to activate discrete muscles. Significant advances in electrode array design focus on increasing selectivity, stability, and functionality of implantable neuroprosthetics. The application of neuroprosthetics to paretic nerves or even directly stimulating or recording from the central nervous system holds great potential in advancing the field of nerve and tissue bioelectric engineering and contributing to clinical care. Although current physiotherapeutic and surgical treatments seek to restore function, structure, or comfort, they bear significant limitations in enabling cosmetic or functional recovery. Instead, the introduction of bioelectric technology may play a role in the restoration of function in patients with neurologic deficits.

Structural dynamic analysis of the Space Shuttle Main Engine

NASA Technical Reports Server (NTRS)

Scott, L. P.; Jamison, G. T.; Mccutcheon, W. A.; Price, J. M.

1981-01-01

This structural dynamic analysis supports development of the SSME by evaluating components subjected to critical dynamic loads, identifying significant parameters, and evaluating solution methods. Engine operating parameters at both rated and full power levels are considered. Detailed structural dynamic analyses of operationally critical and life limited components support the assessment of engine design modifications and environmental changes. Engine system test results are utilized to verify analytic model simulations. The SSME main chamber injector assembly is an assembly of 600 injector elements which are called LOX posts. The overall LOX post analysis procedure is shown.

Advanced materials for aircraft engine applications.

PubMed

Backman, D G; Williams, J C

1992-02-28

A review of advances for aircraft engine structural materials and processes is presented. Improved materials, such as superalloys, and the processes for making turbine disks and blades have had a major impact on the capability of modern gas turbine engines. New structural materials, notably composites and intermetallic materials, are emerging that will eventually further enhance engine performance, reduce engine weight, and thereby enable new aircraft systems. In the future, successful aerospace manufacturers will combine product design and materials excellence with improved manufacturing methods to increase production efficiency, enhance product quality, and decrease the engine development cycle time.

1. Photographic copy of engineering drawing showing structure of Test ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. Photographic copy of engineering drawing showing structure of Test Stand 'B' (4215/E-16), also known as the 'Short Snorter.' California Institute of Technology, Jet Propulsion Laboratory, Plant Engineering 'Structural Addition - Bldg. E-12, Edwards Test Station,' drawing no. E12/1-1, 8 August 1957. - Jet Propulsion Laboratory Edwards Facility, Test Stand B, Edwards Air Force Base, Boron, Kern County, CA

Engineering craniofacial structures: facing the challenge.

PubMed

Zaky, S H; Cancedda, R

2009-12-01

The human innate regenerative ability is known to be limited by the intensity of the insult together with the availability of progenitor cells, which may cause certain irreparable damage. It is only recently that the paradigm of tissue engineering found its way to the treatment of irreversibly affected body structures with the challenge of reconstructing the lost part. In the current review, we underline recent trials that target engineering of human craniofacial structures, mainly bone, cartilage, and teeth. We analyze the applied engineering strategies relative to the selection of cell types to lay down a specific targeted tissue, together with their association with an escorting scaffold for a particular engineered site, and discuss their necessity to be sustained by growth factors. Challenges and expectations for facial skeletal engineering are discussed in the context of future treatment.

Engine System Loads Development for the Fastrac 60K Flight Engine

NASA Technical Reports Server (NTRS)

Frady, Greg; Christensen, Eric R.; Mims, Katherine; Harris, Don; Parks, Russell; Brunty, Joseph

2000-01-01

Early implementation of structural dynamics finite element analyses for calculation of design loads is considered common design practice for high volume manufacturing industries such as automotive and aeronautical industries. However, with the rarity of rocket engine development programs starts, these tools are relatively new to the design of rocket engines. In the new Fastrac engine program, the focus has been to reduce the cost to weight ratio; current structural dynamics analysis practices were tailored in order to meet both production and structural design goals. Perturbation of rocket engine design parameters resulted in a number of Fastrac load cycles necessary to characterize the impact due to mass and stiffness changes. Evolution of loads and load extraction methodologies, parametric considerations and a discussion of load path sensitivities are discussed.

Recent Advances in Structures for Hypersonic Flight, part 2

NASA Technical Reports Server (NTRS)

1978-01-01

The papers at this symposium were presented by 24 speakers representing airframe, missile, and engine manufacturers, the U.S. Air Force, and two NASA Research Centers. The papers cover a variety of topics including engine structures, cooled airframe structures, hot structures, thermal protection systems, cryogenic tankage structures, cryogenic insulations, and analysis methods for thermal/structures.

Optimal CV-22 Centralized Intermediate Repair Facility Locations and Parts Repair

DTIC Science & Technology

2009-06-01

and Reorder Point for TEWS ............................ 36 Table 8. Excel Model for Safety Stock and Reorder Point for FADEC ...Digital Engine Control ( FADEC ) Main Wheel Assembly Blade Fold System Landing Gear Control Panel Drive System Interface Unit Main Landing Gear...Radar 4 Forward Looking Infrared System (FLIR) 4 Tactical Electronic Warfare System (TEWS) 1 Full Authority Digital Engine Control ( FADEC ) 2 Blade

Partnering to develop a talent pipeline for emerging health leaders in operations research.

PubMed

Ng, Alfred; Henshaw, Carly; Carter, Michael

2017-05-01

In initiating its first central office for Quality Improvement (QI), The Scarborough Hospital (TSH) sought to accelerate momentum towards achieving its "Quality and Sustainability" strategic priority by building internal capacity in the emerging QI specialty of operations research. The Scarborough Hospital reviewed existing models of talent management in conjunction with Lean and improvement philosophies. Through simple guiding principles and in collaboration with the University of Toronto's Centre for Healthcare Engineering, TSH developed a targeted approach to talent management for Operations Research (OR) in the Office of Innovation and Performance Improvement, reduced the time from staffing need to onboarding, accelerated the development of new staff in delivering QI and OR projects, and defined new structures and processes to retain and develop this group of new emerging health leaders.

Real-time powder diffraction studies of energy materials under non-equilibrium conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Peterson, Vanessa K.; Auckett, Josie E.; Pang, Wei-Kong

Energy materials form the central part of energy devices. An essential part of their function is the ability to reversibly host charge or energy carriers, and analysis of their phase composition and structure in real time under non-equilibrium conditions is mandatory for a full understanding of their atomic-scale functional mechanism. Real-time powder diffraction is increasingly being applied for this purpose, forming a critical step in the strategic chemical engineering of materials with improved behaviour. This topical review gives examples of real-time analysis using powder diffraction of rechargeable battery electrodes and porous sorbent materials used for the separation and storage ofmore » energy-relevant gases to demonstrate advances in the insights which can be gained into their atomic-scale function.« less

Integrated polarization beam splitter with relaxed fabrication tolerances.

PubMed

Pérez-Galacho, D; Halir, R; Ortega-Moñux, A; Alonso-Ramos, C; Zhang, R; Runge, P; Janiak, K; Bach, H-G; Steffan, A G; Molina-Fernández, Í

2013-06-17

Polarization handling is a key requirement for the next generation of photonic integrated circuits (PICs). Integrated polarization beam splitters (PBS) are central elements for polarization management, but their use in PICs is hindered by poor fabrication tolerances. In this work we present a fully passive, highly fabrication tolerant polarization beam splitter, based on an asymmetrical Mach-Zehnder interferometer (MZI) with a Si/SiO(2) Periodic Layer Structure (PLS) on top of one of its arms. By engineering the birefringence of the PLS we are able to design the MZI arms so that sensitivities to the most critical fabrication errors are greatly reduced. Our PBS design tolerates waveguide width variations of 400nm maintaining a polarization extinction ratio better than 13dB in the complete C-Band.

Real-time powder diffraction studies of energy materials under non-equilibrium conditions

PubMed Central

Peterson, Vanessa K.; Auckett, Josie E.; Pang, Wei-Kong

2017-01-01

Energy materials form the central part of energy devices. An essential part of their function is the ability to reversibly host charge or energy carriers, and analysis of their phase composition and structure in real time under non-equilibrium conditions is mandatory for a full understanding of their atomic-scale functional mechanism. Real-time powder diffraction is increasingly being applied for this purpose, forming a critical step in the strategic chemical engineering of materials with improved behaviour. This topical review gives examples of real-time analysis using powder diffraction of rechargeable battery electrodes and porous sorbent materials used for the separation and storage of energy-relevant gases to demonstrate advances in the insights which can be gained into their atomic-scale function. PMID:28989711

Design rules for biomolecular adhesion: lessons from force measurements.

PubMed

Leckband, Deborah

2010-01-01

Cell adhesion to matrix, other cells, or pathogens plays a pivotal role in many processes in biomolecular engineering. Early macroscopic methods of quantifying adhesion led to the development of quantitative models of cell adhesion and migration. The more recent use of sensitive probes to quantify the forces that alter or manipulate adhesion proteins has revealed much greater functional diversity than was apparent from population average measurements of cell adhesion. This review highlights theoretical and experimental methods that identified force-dependent molecular properties that are central to the biological activity of adhesion proteins. Experimental and theoretical methods emphasized in this review include the surface force apparatus, atomic force microscopy, and vesicle-based probes. Specific examples given illustrate how these tools have revealed unique properties of adhesion proteins and their structural origins.

Thermal-structural design study of an airframe-integrated Scramjet

NASA Technical Reports Server (NTRS)

Killackey, J. J.; Katinsky, E. A.; Tepper, S.; Vuigner, A. A.

1978-01-01

Design concepts are developed and evaluated for a cooled structures assembly for the Scramjet engine, for engine subsystems mass, volume, and operating requirements, and for the aircraft/engine interface. A thermal protection system was defined that makes it possible to attain a life of 100 hours and 1000 cycles. The coolant equivalence ratio at the Mach 10 maximum thermal loading condition is 0.6, indicating a capacity for airframe cooling. The mechanical design is feasible for manufacture using conventional materials. For the cooled structures in a six-module engine, the mass per unit capture area is 12.4 KN/sq m. The total weight of a six-module engine assembly including the fuel system is 14.73 KN.

A Comprehensive Approach to Management of Workplace and Environmental Noise at NASA Lewis Research Center

NASA Technical Reports Server (NTRS)

Cooper, Beth A.

1995-01-01

NASA Lewis Research Center is home to more than 100 experimental research testing facilities and laboratories, including large wind tunnels and engine test cells, which in combination create a varied and complex noise environment. Much of the equipment was manufactured prior to the enactment of legislation limiting product noise emissions or occupational noise exposure. Routine facility maintenance and associated construction also contributes to a noise exposure management responsibility which is equal in magnitude and scope to that of several small industrial companies. The Noise Program, centrally managed within the Office of Environmental Programs at LRC, maintains overall responsibility for hearing conservation, community noise control, and acoustical and noise control engineering. Centralized management of the LRC Noise Program facilitates the timely development and implementation of engineered noise control solutions for problems identified via either the Hearing Conservation of Community Noise Program. The key element of the Lewis Research Center Noise Program, Acoustical and Noise Control Engineering Services, is focused on developing solutions that permanently reduce employee and community noise exposure and maximize research productivity by reducing or eliminating administrative and operational controls and by improving the safety and comfort of the work environment. The Hearing Conservation Program provides noise exposure assessment, medical monitoring, and training for civil servant and contractor employees. The Community Noise Program aims to maintain the support of LRC's neighboring communities while enabling necessary research operations to accomplish their programmatic goals. Noise control engineering capability resides within the Noise Program. The noise control engineering, based on specific exposure limits, is a fundamental consideration throughout the design phase of new test facilities, labs, and office buildings. In summary, the Noise Program addresses hearing conservation, community noise control, and acoustical and noise control engineering.

VIPR III VADR SPIDER Structural Design and Analysis

NASA Technical Reports Server (NTRS)

Li, Wesley; Chen, Tony

2016-01-01

In support of the National Aeronautics and Space Administration (NASA) Vehicle Integrated Propulsion Research (VIPR) Phase III team to evaluate the volcanic ash environment effects on the Pratt & Whitney F117-PW-100 turbofan engine, NASA Armstrong Flight Research Center has successfully performed structural design and analysis on the Volcanic Ash Distribution Rig (VADR) and the Structural Particulate Integration Device for Engine Research (SPIDER) for the ash ingestion test. Static and dynamic load analyses were performed to ensure no structural failure would occur during the test. Modal analysis was conducted, and the results were used to develop engine power setting avoidance zones. These engine power setting avoidance zones were defined to minimize the dwell time when the natural frequencies of the VADR/SPIDER system coincided with the excitation frequencies of the engine which was operating at various revolutions per minute. Vortex-induced vibration due to engine suction air flow during the ingestion test was also evaluated, but was not a concern.

Design and test of aircraft engine isolators for reduced interior noise

NASA Technical Reports Server (NTRS)

Unruh, J. F.; Scheidt, D. C.

1982-01-01

Improved engine vibration isolation was proposed to be the most weight and cost efficient retrofit structure-borne noise control measure for single engine general aviation aircraft. A study was carried out the objectives: (1) to develop an engine isolator design specification for reduced interior noise transmission, (2) select/design candidate isolators to meet a 15 dB noise reduction design goal, and (3) carry out a proof of concept evaluation test. Analytical model of the engine, vibration isolators and engine mount structure were coupled to an empirical model of the fuselage for noise transmission evaluation. The model was used to develop engine isolator dynamic properties design specification for reduced noise transmission. Candidate isolators ere chosen from available product literature and retrofit to a test aircraft. A laboratory based test procedure was then developed to simulate engine induced noise transmission in the aircraft for a proof of concept evaluation test. Three candidate isolator configurations were evaluated for reduced structure-borne noise transmission relative to the original equipment isolators.

Integrating centralized and decentralized organization structures: an education and development model.

PubMed

Sheriff, R; Banks, A

2001-01-01

Organization change efforts have led to critically examining the structure of education and development departments within hospitals. This qualitative study evaluated an education and development model in an academic health sciences center. The model combines centralization and decentralization. The study results can be used by staff development educators and administrators when organization structure is questioned. This particular model maximizes the benefits and minimizes the limitations of centralized and decentralized structures.

Alternative Fuels Data Center: Central Ohio Turns Trash Into Natural Gas

Science.gov Websites

electric car. College Students Engineer Efficient Vehicles in EcoCAR 2 Competition Aug. 2, 2014 Photo of a Authority of Central Ohio turns trash into compressed natural gas for fleet fuel. For information about this FuelEconomy.gov. Provided by Maryland Public Television Related Videos Photo of a car Electric Vehicles Charge up

Distributed Engine Control Empirical/Analytical Verification Tools

NASA Technical Reports Server (NTRS)

DeCastro, Jonathan; Hettler, Eric; Yedavalli, Rama; Mitra, Sayan

2013-01-01

NASA's vision for an intelligent engine will be realized with the development of a truly distributed control system featuring highly reliable, modular, and dependable components capable of both surviving the harsh engine operating environment and decentralized functionality. A set of control system verification tools was developed and applied to a C-MAPSS40K engine model, and metrics were established to assess the stability and performance of these control systems on the same platform. A software tool was developed that allows designers to assemble easily a distributed control system in software and immediately assess the overall impacts of the system on the target (simulated) platform, allowing control system designers to converge rapidly on acceptable architectures with consideration to all required hardware elements. The software developed in this program will be installed on a distributed hardware-in-the-loop (DHIL) simulation tool to assist NASA and the Distributed Engine Control Working Group (DECWG) in integrating DCS (distributed engine control systems) components onto existing and next-generation engines.The distributed engine control simulator blockset for MATLAB/Simulink and hardware simulator provides the capability to simulate virtual subcomponents, as well as swap actual subcomponents for hardware-in-the-loop (HIL) analysis. Subcomponents can be the communication network, smart sensor or actuator nodes, or a centralized control system. The distributed engine control blockset for MATLAB/Simulink is a software development tool. The software includes an engine simulation, a communication network simulation, control algorithms, and analysis algorithms set up in a modular environment for rapid simulation of different network architectures; the hardware consists of an embedded device running parts of the CMAPSS engine simulator and controlled through Simulink. The distributed engine control simulation, evaluation, and analysis technology provides unique capabilities to study the effects of a given change to the control system in the context of the distributed paradigm. The simulation tool can support treatment of all components within the control system, both virtual and real; these include communication data network, smart sensor and actuator nodes, centralized control system (FADEC full authority digital engine control), and the aircraft engine itself. The DECsim tool can allow simulation-based prototyping of control laws, control architectures, and decentralization strategies before hardware is integrated into the system. With the configuration specified, the simulator allows a variety of key factors to be systematically assessed. Such factors include control system performance, reliability, weight, and bandwidth utilization.

Protein thermal denaturation is modulated by central residues in the protein structure network.

PubMed

Souza, Valquiria P; Ikegami, Cecília M; Arantes, Guilherme M; Marana, Sandro R

2016-03-01

Network structural analysis, known as residue interaction networks or graphs (RIN or RIG, respectively) or protein structural networks or graphs (PSN or PSG, respectively), comprises a useful tool for detecting important residues for protein function, stability, folding and allostery. In RIN, the tertiary structure is represented by a network in which residues (nodes) are connected by interactions (edges). Such structural networks have consistently presented a few central residues that are important for shortening the pathways linking any two residues in a protein structure. To experimentally demonstrate that central residues effectively participate in protein properties, mutations were directed to seven central residues of the β-glucosidase Sfβgly (β-D-glucoside glucohydrolase; EC 3.2.1.21). These mutations reduced the thermal stability of the enzyme, as evaluated by changes in transition temperature (Tm ) and the denaturation rate at 45 °C. Moreover, mutations directed to the vicinity of a central residue also caused significant decreases in the Tm of Sfβgly and clearly increased the unfolding rate constant at 45 °C. However, mutations at noncentral residues or at surrounding residues did not affect the thermal stability of Sfβgly. Therefore, the data reported in the present study suggest that the perturbation of the central residues reduced the stability of the native structure of Sfβgly. These results are in agreement with previous findings showing that networks are robust, whereas attacks on central nodes cause network failure. Finally, the present study demonstrates that central residues underlie the functional properties of proteins. © 2016 Federation of European Biochemical Societies.

36 CFR 200.1 - Central organization.

Code of Federal Regulations, 2010 CFR

2010-07-01

... National Forest System lands and management of natural resources within the principle of multiple use and... engineering, forest economics and marketing, watersheds, wildlife and fish habitat, range, recreation and...

Outer planet probe engineering model structural tests

NASA Technical Reports Server (NTRS)

Smittkamp, J. A.; Gustin, W. H.; Griffin, M. W.

1977-01-01

A series of proof of concept structural tests was performed on an engineering model of the Outer Planets Atmospheric Entry Probe. The tests consisted of pyrotechnic shock, dynamic and static loadings. The tests partially verified the structural concept.

Engineering and Design: Composite Materials for Civil Engineering Structures

DTIC Science & Technology

1997-03-31

the effects of acidic, salt, and fresh waters . Acidic, salt, and fresh waters are corrosive to ferrous metals. In Corps of Engineers structures, high...what is commonly called a toughened epoxy. (5) Polymeric resins will absorb moisture. Since many applications are in contact with water (at least...ultraviolet radiation. Some coatings can reduce the amount of moisture absorption by the structure. All polymeric resins will absorb water to some

Aero/structural tailoring of engine blades (AERO/STAEBL)

NASA Technical Reports Server (NTRS)

Brown, K. W.

1988-01-01

This report describes the Aero/Structural Tailoring of Engine Blades (AERO/STAEBL) program, which is a computer code used to perform engine fan and compressor blade aero/structural numerical optimizations. These optimizations seek a blade design of minimum operating cost that satisfies realistic blade design constraints. This report documents the overall program (i.e., input, optimization procedures, approximate analyses) and also provides a detailed description of the validation test cases.

On the design and structural analysis of jet engine fan blade structures

NASA Astrophysics Data System (ADS)

Amoo, Leye M.

2013-07-01

Progress in the design and structural analysis of commercial jet engine fan blades is reviewed and presented. This article is motivated by the key role fan blades play in the performance of advanced gas turbine jet engines. The fundamentals of the associated physics are emphasized. Recent developments and advancements have led to an increase and improvement in fan blade structural durability, stability and reliability. This article is intended as a high level review of the fan blade environment and current state of structural design to aid further research in developing new and innovative fan blade technologies.

Evaluation of creative problem-solving abilities in undergraduate structural engineers through interdisciplinary problem-based learning

NASA Astrophysics Data System (ADS)

McCrum, Daniel Patrick

2017-11-01

For a structural engineer, effective communication and interaction with architects cannot be underestimated as a key skill to success throughout their professional career. Structural engineers and architects have to share a common language and understanding of each other in order to achieve the most desirable architectural and structural designs. This interaction and engagement develops during their professional career but needs to be nurtured during their undergraduate studies. The objective of this paper is to present the strategies employed to engage higher order thinking in structural engineering students in order to help them solve complex problem-based learning (PBL) design scenarios presented by architecture students. The strategies employed were applied in the experimental setting of an undergraduate module in structural engineering at Queen's University Belfast in the UK. The strategies employed were active learning to engage with content knowledge, the use of physical conceptual structural models to reinforce key concepts and finally, reinforcing the need for hand sketching of ideas to promote higher order problem-solving. The strategies employed were evaluated through student survey, student feedback and module facilitator (this author) reflection. The strategies were qualitatively perceived by the tutor and quantitatively evaluated by students in a cross-sectional study to help interaction with the architecture students, aid interdisciplinary learning and help students creatively solve problems (through higher order thinking). The students clearly enjoyed this module and in particular interacting with structural engineering tutors and students from another discipline.

Control Centrality and Hierarchical Structure in Complex Networks

PubMed Central

Liu, Yang-Yu; Slotine, Jean-Jacques; Barabási, Albert-László

2012-01-01

We introduce the concept of control centrality to quantify the ability of a single node to control a directed weighted network. We calculate the distribution of control centrality for several real networks and find that it is mainly determined by the network’s degree distribution. We show that in a directed network without loops the control centrality of a node is uniquely determined by its layer index or topological position in the underlying hierarchical structure of the network. Inspired by the deep relation between control centrality and hierarchical structure in a general directed network, we design an efficient attack strategy against the controllability of malicious networks. PMID:23028542

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stella, Stefano; University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen; Molina, Rafael

Crystal structures of BurrH and the BurrH–DNA complex are reported. DNA editing offers new possibilities in synthetic biology and biomedicine for modulation or modification of cellular functions to organisms. However, inaccuracy in this process may lead to genome damage. To address this important problem, a strategy allowing specific gene modification has been achieved through the addition, removal or exchange of DNA sequences using customized proteins and the endogenous DNA-repair machinery. Therefore, the engineering of specific protein–DNA interactions in protein scaffolds is key to providing ‘toolkits’ for precise genome modification or regulation of gene expression. In a search for putative DNA-bindingmore » domains, BurrH, a protein that recognizes a 19 bp DNA target, was identified. Here, its apo and DNA-bound crystal structures are reported, revealing a central region containing 19 repeats of a helix–loop–helix modular domain (BurrH domain; BuD), which identifies the DNA target by a single residue-to-nucleotide code, thus facilitating its redesign for gene targeting. New DNA-binding specificities have been engineered in this template, showing that BuD-derived nucleases (BuDNs) induce high levels of gene targeting in a locus of the human haemoglobin β (HBB) gene close to mutations responsible for sickle-cell anaemia. Hence, the unique combination of high efficiency and specificity of the BuD arrays can push forward diverse genome-modification approaches for cell or organism redesign, opening new avenues for gene editing.« less

Independence of solitary-cation properties on the atomic neighborhood in In1 -xGaxN alloys: A novel perspective for material engineering

NASA Astrophysics Data System (ADS)

Filippone, Francesco; Mattioli, Giuseppe; Amore Bonapasta, Aldo

2017-11-01

In InN, a genuine band gap opening observed after hydrogenation has been explained by means of the "solitary cation" model, a multi-H complex in which the central cation, In*, is fully separated from the structure [Pettinari et al., Adv. Funct. Mater. 25, 5353 (2015), 10.1002/adfm.201501858]. Similar effects of H on the host band gap have been observed in In-rich In1-xGaxN alloys. Paying attention to these materials, we have theoretically investigated the In* properties against three kinds of disorder, structural, compositional, and configurational, all of them possibly occurring in In1-xGaxN alloys. As a first major result we have found that a same, general solitary-cation model and mechanism explain the effects of hydrogenation on the electronic properties of both InN and In-rich In1-xGaxN alloys. Even more interestingly, in these alloys, both the energetics of the In* solitary cations and their effects on the band gap result to be thoroughly independent of their atomic neighborhood, in particular, of the number and spatial distribution of their cation neighbors. Significantly, this implies that band-gap opening effects can be safely predicted in whatever hydrogenated In-rich nitride alloy containing different In companions (e.g., B, Al, or Ga) as well as in InN-containing, unconventional compounds (e.g., ZnO-InN), thus offering novel opportunities for material engineering.

Practical limits for reverse engineering of dynamical systems: a statistical analysis of sensitivity and parameter inferability in systems biology models.

PubMed

Erguler, Kamil; Stumpf, Michael P H

2011-05-01

The size and complexity of cellular systems make building predictive models an extremely difficult task. In principle dynamical time-course data can be used to elucidate the structure of the underlying molecular mechanisms, but a central and recurring problem is that many and very different models can be fitted to experimental data, especially when the latter are limited and subject to noise. Even given a model, estimating its parameters remains challenging in real-world systems. Here we present a comprehensive analysis of 180 systems biology models, which allows us to classify the parameters with respect to their contribution to the overall dynamical behaviour of the different systems. Our results reveal candidate elements of control in biochemical pathways that differentially contribute to dynamics. We introduce sensitivity profiles that concisely characterize parameter sensitivity and demonstrate how this can be connected to variability in data. Systematically linking data and model sloppiness allows us to extract features of dynamical systems that determine how well parameters can be estimated from time-course measurements, and associates the extent of data required for parameter inference with the model structure, and also with the global dynamical state of the system. The comprehensive analysis of so many systems biology models reaffirms the inability to estimate precisely most model or kinetic parameters as a generic feature of dynamical systems, and provides safe guidelines for performing better inferences and model predictions in the context of reverse engineering of mathematical models for biological systems.

Effects of chemical equilibrium on turbine engine performance for various fuels and combustor temperatures

NASA Technical Reports Server (NTRS)

Tran, Donald H.; Snyder, Christopher A.

1992-01-01

A study was performed to quantify the differences in turbine engine performance with and without the chemical dissociation effects for various fuel types over a range of combustor temperatures. Both turbojet and turbofan engines were studied with hydrocarbon fuels and cryogenic, nonhydrocarbon fuels. Results of the study indicate that accuracy of engine performance decreases when nonhydrocarbon fuels are used, especially at high temperatures where chemical dissociation becomes more significant. For instance, the deviation in net thrust for liquid hydrogen fuel can become as high as 20 percent at 4160 R. This study reveals that computer central processing unit (CPU) time increases significantly when dissociation effects are included in the cycle analysis.

48 CFR 836.603 - Collecting data on and appraising firms qualifications.

Code of Federal Regulations, 2012 CFR

2012-10-01

... Construction and Facilities Management, for Central Office; the Director, Office of Construction Management... VETERANS AFFAIRS SPECIAL CATEGORIES OF CONTRACTING CONSTRUCTION AND ARCHITECT-ENGINEER CONTRACTS Architect...

48 CFR 836.603 - Collecting data on and appraising firms qualifications.

Code of Federal Regulations, 2014 CFR

2014-10-01

... Construction and Facilities Management, for Central Office; the Director, Office of Construction Management... VETERANS AFFAIRS SPECIAL CATEGORIES OF CONTRACTING CONSTRUCTION AND ARCHITECT-ENGINEER CONTRACTS Architect...

48 CFR 836.603 - Collecting data on and appraising firms qualifications.

Code of Federal Regulations, 2011 CFR

2011-10-01

... Construction and Facilities Management, for Central Office; the Director, Office of Construction Management... VETERANS AFFAIRS SPECIAL CATEGORIES OF CONTRACTING CONSTRUCTION AND ARCHITECT-ENGINEER CONTRACTS Architect...

48 CFR 836.603 - Collecting data on and appraising firms qualifications.

Code of Federal Regulations, 2013 CFR

2013-10-01

... Construction and Facilities Management, for Central Office; the Director, Office of Construction Management... VETERANS AFFAIRS SPECIAL CATEGORIES OF CONTRACTING CONSTRUCTION AND ARCHITECT-ENGINEER CONTRACTS Architect...

48 CFR 836.603 - Collecting data on and appraising firms qualifications.

Code of Federal Regulations, 2010 CFR

2010-10-01

... Construction and Facilities Management, for Central Office; the Director, Office of Construction Management... VETERANS AFFAIRS SPECIAL CATEGORIES OF CONTRACTING CONSTRUCTION AND ARCHITECT-ENGINEER CONTRACTS Architect...

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xie, Wei; Lei, Wei-Hua; Wang, Ding-Xiong, E-mail: leiwh@hust.edu.cn

Recently, two empirical correlations related to the minimum variability timescale (MTS) of the light curves are discovered in gamma-ray bursts (GRBs). One is the anti-correlation between MTS and Lorentz factor Γ, and the other is the anti-correlation between the MTS and gamma-ray luminosity L {sub γ}. Both of the two correlations might be used to explore the activity of the central engine of GRBs. In this paper, we try to understand these empirical correlations by combining two popular black hole central engine models (namely, the Blandford and Znajek mechanism (BZ) and the neutrino-dominated accretion flow (NDAF)). By taking the MTSmore » as the timescale of viscous instability of the NDAF, we find that these correlations favor the scenario in which the jet is driven by the BZ mechanism.« less

Electromobility concept for racing cars based on lithium-ion batteries and supercapacitors

NASA Astrophysics Data System (ADS)

Frenzel, B.; Kurzweil, P.; Rönnebeck, H.

For the construction of an all-electric race car, all aspects from engineering design over cost estimation up to the road capability are illuminated. From the most promising batteries for electric vehicle propulsion, the state-of-the art and commercial availability of lithium-ion secondary batteries is critically discussed with respect to cycle-life and unfavorable charge-discharge conditions. A market-overview is given with respect to a small electric car. Different combinations of electric motors and a recuperation system have been investigated. Weight aspects of central drive systems were considered and compared with decentralized wheel-hub drives. As a result, a centralized high-speed drive train based on a permanent-magnet synchronous engine with high-energy magnets seems to be superior due to limited space for assembly.

Anatomy and evolution of database search engines-a central component of mass spectrometry based proteomic workflows.

PubMed

Verheggen, Kenneth; Raeder, Helge; Berven, Frode S; Martens, Lennart; Barsnes, Harald; Vaudel, Marc

2017-09-13

Sequence database search engines are bioinformatics algorithms that identify peptides from tandem mass spectra using a reference protein sequence database. Two decades of development, notably driven by advances in mass spectrometry, have provided scientists with more than 30 published search engines, each with its own properties. In this review, we present the common paradigm behind the different implementations, and its limitations for modern mass spectrometry datasets. We also detail how the search engines attempt to alleviate these limitations, and provide an overview of the different software frameworks available to the researcher. Finally, we highlight alternative approaches for the identification of proteomic mass spectrometry datasets, either as a replacement for, or as a complement to, sequence database search engines. © 2017 Wiley Periodicals, Inc.

Multi-cylinder hot gas engine

DOEpatents

Corey, John A.

1985-01-01

A multi-cylinder hot gas engine having an equal angle, V-shaped engine block in which two banks of parallel, equal length, equally sized cylinders are formed together with annular regenerator/cooler units surrounding each cylinder, and wherein the pistons are connected to a single crankshaft. The hot gas engine further includes an annular heater head disposed around a central circular combustor volume having a new balanced-flow hot-working-fluid manifold assembly that provides optimum balanced flow of the working fluid through the heater head working fluid passageways which are connected between each of the cylinders and their respective associated annular regenerator units. This balanced flow provides even heater head temperatures and, therefore, maximum average working fluid temperature for best operating efficiency with the use of a single crankshaft V-shaped engine block.

Rocket Engine Oscillation Diagnostics

NASA Technical Reports Server (NTRS)

Nesman, Tom; Turner, James E. (Technical Monitor)

2002-01-01

Rocket engine oscillating data can reveal many physical phenomena ranging from unsteady flow and acoustics to rotordynamics and structural dynamics. Because of this, engine diagnostics based on oscillation data should employ both signal analysis and physical modeling. This paper describes an approach to rocket engine oscillation diagnostics, types of problems encountered, and example problems solved. Determination of design guidelines and environments (or loads) from oscillating phenomena is required during initial stages of rocket engine design, while the additional tasks of health monitoring, incipient failure detection, and anomaly diagnostics occur during engine development and operation. Oscillations in rocket engines are typically related to flow driven acoustics, flow excited structures, or rotational forces. Additional sources of oscillatory energy are combustion and cavitation. Included in the example problems is a sampling of signal analysis tools employed in diagnostics. The rocket engine hardware includes combustion devices, valves, turbopumps, and ducts. Simple models of an oscillating fluid system or structure can be constructed to estimate pertinent dynamic parameters governing the unsteady behavior of engine systems or components. In the example problems it is shown that simple physical modeling when combined with signal analysis can be successfully employed to diagnose complex rocket engine oscillatory phenomena.

NASA GSFC Mechanical Engineering Latest Inputs for Verification Standards (GEVS) Updates

NASA Technical Reports Server (NTRS)

Kaufman, Daniel

2003-01-01

This viewgraph presentation provides information on quality control standards in mechanical engineering. The presentation addresses safety, structural loads, nonmetallic composite structural elements, bonded structural joints, externally induced shock, random vibration, acoustic tests, and mechanical function.

14 CFR 29.549 - Fuselage and rotor pylon structures.

Code of Federal Regulations, 2011 CFR

2011-01-01

... flight conditions, must be considered. (c) Each engine mount and adjacent fuselage structure must be designed to withstand the loads occurring under accelerated flight and landing conditions, including engine torque. (d) [Reserved] (e) If approval for the use of 21/2-minute OEI power is requested, each engine...

14 CFR 29.549 - Fuselage and rotor pylon structures.

Code of Federal Regulations, 2013 CFR

2013-01-01

... flight conditions, must be considered. (c) Each engine mount and adjacent fuselage structure must be designed to withstand the loads occurring under accelerated flight and landing conditions, including engine torque. (d) [Reserved] (e) If approval for the use of 21/2-minute OEI power is requested, each engine...

14 CFR 29.549 - Fuselage and rotor pylon structures.

Code of Federal Regulations, 2010 CFR

2010-01-01

... flight conditions, must be considered. (c) Each engine mount and adjacent fuselage structure must be designed to withstand the loads occurring under accelerated flight and landing conditions, including engine torque. (d) [Reserved] (e) If approval for the use of 21/2-minute OEI power is requested, each engine...

14 CFR 29.549 - Fuselage and rotor pylon structures.

Code of Federal Regulations, 2012 CFR

2012-01-01

... flight conditions, must be considered. (c) Each engine mount and adjacent fuselage structure must be designed to withstand the loads occurring under accelerated flight and landing conditions, including engine torque. (d) [Reserved] (e) If approval for the use of 21/2-minute OEI power is requested, each engine...

14 CFR 29.549 - Fuselage and rotor pylon structures.

Code of Federal Regulations, 2014 CFR

2014-01-01

... flight conditions, must be considered. (c) Each engine mount and adjacent fuselage structure must be designed to withstand the loads occurring under accelerated flight and landing conditions, including engine torque. (d) [Reserved] (e) If approval for the use of 21/2-minute OEI power is requested, each engine...

7 CFR Exhibit B to Subpart A of... - Requirements for Modular/Panelized Housing Units

Code of Federal Regulations, 2013 CFR

2013-01-01

... Regional Letters of Acceptance (RLA), Truss Connector Bulletins (TCB): and, Mechanical Engineering... issued by HUD include: Structural Engineering Bulletins (SEB) on a national basis, Area Letters of... Category III housing (modular/panelized housing that does not have to have a Structural Engineering...

7 CFR Exhibit B to Subpart A of... - Requirements for Modular/Panelized Housing Units

Code of Federal Regulations, 2014 CFR

2014-01-01

... Regional Letters of Acceptance (RLA), Truss Connector Bulletins (TCB): and, Mechanical Engineering... issued by HUD include: Structural Engineering Bulletins (SEB) on a national basis, Area Letters of... Category III housing (modular/panelized housing that does not have to have a Structural Engineering...

7 CFR Exhibit B to Subpart A of... - Requirements for Modular/Panelized Housing Units

Code of Federal Regulations, 2012 CFR

2012-01-01

... Regional Letters of Acceptance (RLA), Truss Connector Bulletins (TCB): and, Mechanical Engineering... issued by HUD include: Structural Engineering Bulletins (SEB) on a national basis, Area Letters of... Category III housing (modular/panelized housing that does not have to have a Structural Engineering...

Composite mechanics for engine structures

NASA Technical Reports Server (NTRS)

Chamis, Christos C.

1987-01-01

Recent research activities and accomplishments at Lewis Research Center on composite mechanics for engine structures are summarized. The activities focused mainly on developing procedures for the computational simulation of composite intrinsic and structural behavior. The computational simulation encompasses all aspects of composite mechanics, advanced three-dimensional finite-element methods, damage tolerance, composite structural and dynamic response, and structural tailoring and optimization.

Composite mechanics for engine structures

NASA Technical Reports Server (NTRS)

Chamis, Christos C.

1989-01-01

Recent research activities and accomplishments at Lewis Research Center on composite mechanics for engine structures are summarized. The activities focused mainly on developing procedures for the computational simulation of composite intrinsic and structural behavior. The computational simulation encompasses all aspects of composite mechanics, advanced three-dimensional finite-element methods, damage tolerance, composite structural and dynamic response, and structural tailoring and optimization.

This photocopy of an engineering drawing shows the floor plan ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

This photocopy of an engineering drawing shows the floor plan of the Liner Lab, including room functions. Austin, Field & Fry, Architects Engineers, 22311 West Third Street, Los Angeles 57, California: Edwards Test Station Complex Phase II, Jet Propulsion Laboratory, California Institute of Technology, Edwards Air Force Base, Edwards, California: "Liner Laboratory, Floor Plan and Schedules," drawing no. E33/4-2, 26 June 1962. California Institute of Technology, Jet Propulsion Laboratory, Plant Engineering: engineering drawings of structures at JPL Edwards Facility. Drawings on file at JPL Plant Engineering, Pasadena, California. California Institute of Technology, Jet Propulsion Laboratory, Plant Engineering: engineering drawings of structures at JPL Edwards Facility. Drawings on file at JPL Plant Engineering, Pasadena, California - Jet Propulsion Laboratory Edwards Facility, Liner Laboratory, Edwards Air Force Base, Boron, Kern County, CA

Geologic Map and Map Database of Eastern Sonoma and Western Napa Counties, California

USGS Publications Warehouse

Graymer, R.W.; Brabb, E.E.; Jones, D.L.; Barnes, J.; Nicholson, R.S.; Stamski, R.E.

2007-01-01

Introduction This report contains a new 1:100,000-scale geologic map, derived from a set of geologic map databases (Arc-Info coverages) containing information at 1:62,500-scale resolution, and a new description of the geologic map units and structural relations in the map area. Prepared as part of the San Francisco Bay Region Mapping Project, the study area includes the north-central part of the San Francisco Bay region, and forms the final piece of the effort to generate new, digital geologic maps and map databases for an area which includes Alameda, Contra Costa, Marin, Napa, San Francisco, San Mateo, Santa Clara, Santa Cruz, Solano, and Sonoma Counties. Geologic mapping in Lake County in the north-central part of the map extent was not within the scope of the Project. The map and map database integrates both previously published reports and new geologic mapping and field checking by the authors (see Sources of Data index map on the map sheet or the Arc-Info coverage eswn-so and the textfile eswn-so.txt). This report contains new ideas about the geologic structures in the map area, including the active San Andreas Fault system, as well as the geologic units and their relations. Together, the map (or map database) and the unit descriptions in this report describe the composition, distribution, and orientation of geologic materials and structures within the study area at regional scale. Regional geologic information is important for analysis of earthquake shaking, liquifaction susceptibility, landslide susceptibility, engineering materials properties, mineral resources and hazards, as well as groundwater resources and hazards. These data also assist in answering questions about the geologic history and development of the California Coast Ranges.

Optimal fitting of Gaussian-apodized or under-resolved emission lines in Fourier transform spectra providing new insights on the velocity structure of NGC 6720

NASA Astrophysics Data System (ADS)

Martin, Thomas B.; Prunet, Simon; Drissen, Laurent

2016-12-01

An analysis of the kinematics of NGC 6720 is performed on the commissioning data obtained with SITELLE, the Canada-France-Hawaii Telescope's new imaging Fourier transform spectrometer. In order to measure carefully the small broadening effect of a shell expansion on an unresolved emission line, we have determined a computationally robust implementation of the convolution of a Gaussian with a sinc instrumental line shape which avoids arithmetic overflows. This model can be used to measure line broadening of typically a few km s-1 even at low spectral resolution (R < 5000). We have also designed the corresponding set of Gaussian apodizing functions that are now used by ORBS, the SITELLE's reduction pipeline. We have implemented this model in ORCS, a fitting engine for SITELLE's data, and used it to derive the [S II] density map of the central part of the nebula. The study of the broadening of the [N II] lines shows that the main ring and the central lobe are two different shells with different expansion velocities. We have also derived deep and spatially resolved velocity maps of the halo in [N II] and Hα and found that the brightest bubbles are originating from two bipolar structures with a velocity difference of more than 35 km s-1 lying at the poles of a possibly unique halo shell expanding at a velocity of more than 15 km s-1.

Extending SME to Handle Large-Scale Cognitive Modeling.

PubMed

Forbus, Kenneth D; Ferguson, Ronald W; Lovett, Andrew; Gentner, Dedre

2017-07-01

Analogy and similarity are central phenomena in human cognition, involved in processes ranging from visual perception to conceptual change. To capture this centrality requires that a model of comparison must be able to integrate with other processes and handle the size and complexity of the representations required by the tasks being modeled. This paper describes extensions to Structure-Mapping Engine (SME) since its inception in 1986 that have increased its scope of operation. We first review the basic SME algorithm, describe psychological evidence for SME as a process model, and summarize its role in simulating similarity-based retrieval and generalization. Then we describe five techniques now incorporated into the SME that have enabled it to tackle large-scale modeling tasks: (a) Greedy merging rapidly constructs one or more best interpretations of a match in polynomial time: O(n 2 log(n)); (b) Incremental operation enables mappings to be extended as new information is retrieved or derived about the base or target, to model situations where information in a task is updated over time; (c) Ubiquitous predicates model the varying degrees to which items may suggest alignment; (d) Structural evaluation of analogical inferences models aspects of plausibility judgments; (e) Match filters enable large-scale task models to communicate constraints to SME to influence the mapping process. We illustrate via examples from published studies how these enable it to capture a broader range of psychological phenomena than before. Copyright © 2016 Cognitive Science Society, Inc.

Multidisciplinary Simulation of Graphite-Composite and Cermet Fuel Elements for NTP Point of Departure Designs

NASA Technical Reports Server (NTRS)

Stewart, Mark E.; Schnitzler, Bruce G.

2015-01-01

This paper compares the expected performance of two Nuclear Thermal Propulsion fuel types. High fidelity, fluid/thermal/structural + neutronic simulations help predict the performance of graphite-composite and cermet fuel types from point of departure engine designs from the Nuclear Thermal Propulsion project. Materials and nuclear reactivity issues are reviewed for each fuel type. Thermal/structural simulations predict thermal stresses in the fuel and thermal expansion mis-match stresses in the coatings. Fluid/thermal/structural/neutronic simulations provide predictions for full fuel elements. Although NTP engines will utilize many existing chemical engine components and technologies, nuclear fuel elements are a less developed engine component and introduce design uncertainty. Consequently, these fuel element simulations provide important insights into NTP engine performance.

Example of International Co-Operation in the Frame of the Project Phare (TEMPUS) in Innovations in Teaching of Environmental Hydrogeology in Engineering Education in the Czech Republic.

ERIC Educational Resources Information Center

Grmela, Arnost; Rapantova, Nadia

The international TEMPUS (Trans-European Co-operating and Mobility Scheme for Higher Education between Central/Eastern Europe and European Union) project lasted from 1995-1997. In the framework of TEMPUS, a material and knowledge background was developed in order to ensure the education of the branch Geological Engineering with specialization in…

PR[superscript 2]EPS: Preparation, Recruitment, Retention and Excellence in the Physical Sciences, Including Engineering. A Report on the 2004, 2005 and 2006 Science Summer Camps

ERIC Educational Resources Information Center

Bachman, Nancy J.; Bischoff, Paul J.; Gallagher, Hugh; Labroo, Sunil; Schaumloffel, John C.

2008-01-01

Now in its fourth year, PR[superscript 2]EPS is a National Science Foundation funded initiative designed to recruit high school students to attend college majoring in the physical sciences, including engineering and secondary science education, and to help ensure their retention within the program until graduation. A central feature of the…

THREE-DIMENSIONAL SIMULATIONS OF LONG DURATION GAMMA-RAY BURST JETS: TIMESCALES FROM VARIABLE ENGINES

DOE Office of Scientific and Technical Information (OSTI.GOV)

López-Cámara, D.; Lazzati, Davide; Morsony, Brian J., E-mail: diego@astro.unam.mx

2016-08-01

Gamma-ray burst (GRB) light curves are characterized by marked variability, each showing unique properties. The origin of this variability, at least for a fraction of long GRBs, may be the result of an unsteady central engine. It is thus important to study the effects that an episodic central engine has on the jet propagation and, eventually, on the prompt emission within the collapsar scenario. Thus, in this study we follow the interaction of pulsed outflows with their progenitor stars with hydrodynamic numerical simulations in both two and three dimensions. We show that the propagation of unsteady jets is affected bymore » the interaction with the progenitor material well after the break-out time, especially for jets with long quiescent times comparable to or larger than a second. We also show that this interaction can lead to an asymmetric behavior in which pulse durations and quiescent periods are systematically different. After the pulsed jets drill through the progenitor and the interstellar medium, we find that, on average, the quiescent epochs last longer than the pulses (even in simulations with symmetrical active and quiescent engine times). This could explain the asymmetry detected in the light curves of long quiescent time GRBs.« less

Information-seeking behavior of basic science researchers: implications for library services.

PubMed

Haines, Laura L; Light, Jeanene; O'Malley, Donna; Delwiche, Frances A

2010-01-01

This study examined the information-seeking behaviors of basic science researchers to inform the development of customized library services. A qualitative study using semi-structured interviews was conducted on a sample of basic science researchers employed at a university medical school. The basic science researchers used a variety of information resources ranging from popular Internet search engines to highly technical databases. They generally relied on basic keyword searching, using the simplest interface of a database or search engine. They were highly collegial, interacting primarily with coworkers in their laboratories and colleagues employed at other institutions. They made little use of traditional library services and instead performed many traditional library functions internally. Although the basic science researchers expressed a positive attitude toward the library, they did not view its resources or services as integral to their work. To maximize their use by researchers, library resources must be accessible via departmental websites. Use of library services may be increased by cultivating relationships with key departmental administrative personnel. Despite their self-sufficiency, subjects expressed a desire for centralized information about ongoing research on campus and shared resources, suggesting a role for the library in creating and managing an institutional repository.

A 50 kilowatt distributed grid-connected photovoltaic generation system for the University of Wyoming

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chowdhury, B.H.; Muknahallipatna, S.; Cupal, J.J.

The University of Wyoming (UW) campus is serving as the site for a 50 kilowatt solar photovoltaic (PV) system. Three sub-systems were sited and built on the UW campus in 1996. The first sub-system, a 10 kW roof-integrated system of PV roof tiles is located on the roof of the Engineering building. The second sub-system--a 5 kW rack-mounted, ballasted PV system is on a walkway roof of the Engineering building. The third sub-system is a 35 kW shade structure system and located adjacent to the parking lot of the university`s football stadium. The three sub-systems differ in their design strategymore » since each is being used for research and education at the university. Each sub-system, being located at some distance away from one another, supplies a different part of the campus grid. Efforts continue at setting up a central monitoring system which will receive data remotely from all locations. A part of this monitoring system is complete. While the initial monitoring data shows satisfactory performance, a number of reliability problems with PV modules and inverters have delayed full functionality of the system.« less

Information-seeking behavior of basic science researchers: implications for library services

PubMed Central

Haines, Laura L.; Light, Jeanene; O'Malley, Donna; Delwiche, Frances A.

2010-01-01

Objectives: This study examined the information-seeking behaviors of basic science researchers to inform the development of customized library services. Methods: A qualitative study using semi-structured interviews was conducted on a sample of basic science researchers employed at a university medical school. Results: The basic science researchers used a variety of information resources ranging from popular Internet search engines to highly technical databases. They generally relied on basic keyword searching, using the simplest interface of a database or search engine. They were highly collegial, interacting primarily with coworkers in their laboratories and colleagues employed at other institutions. They made little use of traditional library services and instead performed many traditional library functions internally. Conclusions: Although the basic science researchers expressed a positive attitude toward the library, they did not view its resources or services as integral to their work. To maximize their use by researchers, library resources must be accessible via departmental websites. Use of library services may be increased by cultivating relationships with key departmental administrative personnel. Despite their self-sufficiency, subjects expressed a desire for centralized information about ongoing research on campus and shared resources, suggesting a role for the library in creating and managing an institutional repository. PMID:20098658

American power conference: Proceedings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1994-01-01

The first volume of this conference contains papers on the following topics: (1) Controls, monitoring, and expert systems (Harnessing microprocessor revolution for a more competitive power industry; Plant control--Upgrades; Neural network applications); (2) Diversification and globalization (Electric utility diversification/globalization--Panel; Private power in developing countries); (3) Environment and clean air (Clean Air compliance costs; Site selection for power stations and related facilities; Electric utility trace substance emissions; Solid waste disposal and commercial use; Precipitators/fabric filters; and Effect of flow modifications on fisheries and water quality); (4) Generation--Fuel options equipment (Alternate fuels; Advances in fuel cells for electric power applications; Secondary containmentmore » and seismic requirements for petrochemical facilities; Clean coal technology demonstration; Advanced energy systems; Hydropower); (5) Nuclear operations options (Radioactive waste management and disposal; Off normal conditions; Advanced light water reactors--15 years after TMI; Structural dynamic analyses for nuclear power plants); (6) Retrofit, betterment, repowering maintenance (Project management; Improving competitiveness through process re-engineering; Central stations; Water and wastewater treatment); (7) System planning, operation demand maintenance (Transmission system access; Stability; Systems planning); (8) Transmission and distribution (Transformers; Relaying for system protection; Managing EMF effects); and (9) Education (Power engineering). 155 papers have been processed separately for inclusion on the data base.« less

Los Alamos science, Number 14

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1986-01-01

Nine authored articles are included covering: natural heat engine, photoconductivity, the Caribbean Basin, energy in Central America, peat, geothermal energy, and the MANIAC computer. Separate abstracts were prepared for the articles. (DLC)

DETERMINATION OF CENTRAL ENGINE POSITION AND ACCRETION DISK STRUCTURE IN NGC 4261 BY CORE SHIFT MEASUREMENTS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Haga, Takafumi; Doi, Akihiro; Murata, Yasuhiro

2015-07-01

We report multifrequency phase-referenced observations of the nearby radio galaxy NGC 4261, which has prominent two-sided jets, using the Very Long Baseline Array at 1.4–43 GHz. We measured radio core positions showing observing frequency dependences (known as “core shift”) in both approaching jets and counterjets. The limit of the core position as the frequency approaches infinity, which suggests a jet base, is separated by 82 ± 16 μas upstream in projection, corresponding to (310 ± 60)R{sub s} (R{sub s}: Schwarzschild radius) as a deprojected distance, from the 43 GHz core in the approaching jet. In addition, the innermost component atmore » the counterjet side appeared to approach the same position at infinity of the frequency, indicating that cores on both sides are approaching the same position, suggesting a spatial coincidence with the central engine. Applying a phase-referencing technique, we also obtained spectral index maps, which indicate that emission from the counterjet is affected by free–free absorption (FFA). The result of the core shift profile on the counterjet also requires FFA because the core positions at 5–15 GHz cannot be explained by a simple core shift model based on synchrotron self-absorption (SSA). Our result is apparently consistent with the SSA core shift with an additional disk-like absorber over the counterjet side. Core shift and opacity profiles at the counterjet side suggest a two-component accretion: a radiatively inefficient accretion flow at the inner region and a truncated thin disk in the outer region. We proposed a possible solution about density and temperature profiles in the outer disk on the basis of the radio observation.« less

Structural basis of Zika virus helicase in recognizing its substrates.

PubMed

Tian, Hongliang; Ji, Xiaoyun; Yang, Xiaoyun; Zhang, Zhongxin; Lu, Zuokun; Yang, Kailin; Chen, Cheng; Zhao, Qi; Chi, Heng; Mu, Zhongyu; Xie, Wei; Wang, Zefang; Lou, Huiqiang; Yang, Haitao; Rao, Zihe

2016-08-01

The recent explosive outbreak of Zika virus (ZIKV) infection has been reported in South and Central America and the Caribbean. Neonatal microcephaly associated with ZIKV infection has already caused a public health emergency of international concern. No specific vaccines or drugs are currently available to treat ZIKV infection. The ZIKV helicase, which plays a pivotal role in viral RNA replication, is an attractive target for therapy. We determined the crystal structures of ZIKV helicase-ATP-Mn(2+) and ZIKV helicase-RNA. This is the first structure of any flavivirus helicase bound to ATP. Comparisons with related flavivirus helicases have shown that although the critical P-loop in the active site has variable conformations among different species, it adopts an identical mode to recognize ATP/Mn(2+). The structure of ZIKV helicase-RNA has revealed that upon RNA binding, rotations of the motor domains can cause significant conformational changes. Strikingly, although ZIKV and dengue virus (DENV) apo-helicases share conserved residues for RNA binding, their different manners of motor domain rotations result in distinct individual modes for RNA recognition. It suggests that flavivirus helicases could have evolved a conserved engine to convert chemical energy from nucleoside triphosphate to mechanical energy for RNA unwinding, but different motor domain rotations result in variable RNA recognition modes to adapt to individual viral replication.

Formation of highly stable chimeric trimers by fusion of an adenovirus fiber shaft fragment with the foldon domain of bacteriophage t4 fibritin.

PubMed

Papanikolopoulou, Katerina; Forge, Vincent; Goeltz, Pierrette; Mitraki, Anna

2004-03-05

The folding of beta-structured, fibrous proteins is a largely unexplored area. A class of such proteins is used by viruses as adhesins, and recent studies revealed novel beta-structured motifs for them. We have been studying the folding and assembly of adenovirus fibers that consist of a globular C-terminal domain, a central fibrous shaft, and an N-terminal part that attaches to the viral capsid. The globular C-terminal, or "head" domain, has been postulated to be necessary for the trimerization of the fiber and might act as a registration signal that directs its correct folding and assembly. In this work, we replaced the head of the fiber by the trimerization domain of the bacteriophage T4 fibritin, termed "foldon." Two chimeric proteins, comprising the foldon domain connected at the C-terminal end of four fiber shaft repeats with or without the use of a natural linker sequence, fold into highly stable, SDS-resistant trimers. The structural signatures of the chimeric proteins as seen by CD and infrared spectroscopy are reported. The results suggest that the foldon domain can successfully replace the fiber head domain in ensuring correct trimerization of the shaft sequences. Biological implications and implications for engineering highly stable, beta-structured nanorods are discussed.

Designer nanomaterials using chiral self-assembling peptide systems and their emerging benefit for society.

PubMed

Luo, Zhongli; Zhang, Shuguang

2012-07-07

Chirality is absolutely central in chemistry and biology. The recent findings of chiral self-assembling peptides' remarkable chemical complementarity and structural compatibility make it one of the most inspired designer materials and structures in nanobiotechnology. The emerging field of designer chemistry and biology further explores biological and medical applications of these simple D,L- amino acids through producing marvellous nanostructures under physiological conditions. These self-assembled structures include well-ordered nanofibers, nanotubes and nanovesicles. These structures have been used for 3-dimensional tissue cultures of primary cells and stem cells, sustained release of small molecules, growth factors and monoclonal antibodies, accelerated wound-healing in reparative and regenerative medicine as well as tissue engineering. Recent advances in molecular designs have also led to the development of 3D fine-tuned bioactive tissue culture scaffolds. They are also used to stabilize membrane proteins including difficult G-protein coupled receptors for designing nanobiodevices. One of the self-assembling peptides has been used in human clinical trials for accelerated wound-healings. It is our hope that these peptide materials will open doors for more and diverse clinical uses. The field of chiral self-assembling peptide nanobiotechnology is growing in a number of directions that has led to many surprises in areas of novel materials, synthetic biology, clinical medicine and beyond.

Structurally detailed coarse-grained model for Sec-facilitated co-translational protein translocation and membrane integration

PubMed Central

Miller, Thomas F.

2017-01-01

We present a coarse-grained simulation model that is capable of simulating the minute-timescale dynamics of protein translocation and membrane integration via the Sec translocon, while retaining sufficient chemical and structural detail to capture many of the sequence-specific interactions that drive these processes. The model includes accurate geometric representations of the ribosome and Sec translocon, obtained directly from experimental structures, and interactions parameterized from nearly 200 μs of residue-based coarse-grained molecular dynamics simulations. A protocol for mapping amino-acid sequences to coarse-grained beads enables the direct simulation of trajectories for the co-translational insertion of arbitrary polypeptide sequences into the Sec translocon. The model reproduces experimentally observed features of membrane protein integration, including the efficiency with which polypeptide domains integrate into the membrane, the variation in integration efficiency upon single amino-acid mutations, and the orientation of transmembrane domains. The central advantage of the model is that it connects sequence-level protein features to biological observables and timescales, enabling direct simulation for the mechanistic analysis of co-translational integration and for the engineering of membrane proteins with enhanced membrane integration efficiency. PMID:28328943

Computational flow field in energy efficient engine (EEE)

NASA Astrophysics Data System (ADS)

Miki, Kenji; Moder, Jeff; Liou, Meng-Sing

2016-11-01

In this paper, preliminary results for the recently-updated Open National Combustor Code (Open NCC) as applied to the EEE are presented. The comparison between two different numerical schemes, the standard Jameson-Schmidt-Turkel (JST) scheme and the advection upstream splitting method (AUSM), is performed for the cold flow and the reacting flow calculations using the RANS. In the cold flow calculation, the AUSM scheme predicts a much stronger reverse flow in the central recirculation zone. In the reacting flow calculation, we test two cases: gaseous fuel injection and liquid spray injection. In the gaseous fuel injection case, the overall flame structures of the two schemes are similar to one another, in the sense that the flame is attached to the main nozzle, but is detached from the pilot nozzle. However, in the exit temperature profile, the AUSM scheme shows a more uniform profile than that of the JST scheme, which is close to the experimental data. In the liquid spray injection case, we expect different flame structures in this scenario. We will give a brief discussion on how two numerical schemes predict the flame structures inside the Eusing different ways to introduce the fuel injection. Supported by NASA's Transformational Tools and Technologies project.

Computational Flow Field in Energy Efficient Engine (EEE)

NASA Technical Reports Server (NTRS)

Miki, Kenji; Moder, Jeff; Liou, Meng-Sing

2016-01-01

In this paper, preliminary results for the recently-updated Open National Combustion Code (Open NCC) as applied to the EEE are presented. The comparison between two different numerical schemes, the standard Jameson-Schmidt-Turkel (JST) scheme and the advection upstream splitting method (AUSM), is performed for the cold flow and the reacting flow calculations using the RANS. In the cold flow calculation, the AUSM scheme predicts a much stronger reverse flow in the central recirculation zone. In the reacting flow calculation, we test two cases: gaseous fuel injection and liquid spray injection. In the gaseous fuel injection case, the overall flame structures of the two schemes are similar to one another, in the sense that the flame is attached to the main nozzle, but is detached from the pilot nozzle. However, in the exit temperature profile, the AUSM scheme shows a more uniform profile than that of the JST scheme, which is close to the experimental data. In the liquid spray injection case, we expect different flame structures in this scenario. We will give a brief discussion on how two numerical schemes predict the flame structures inside the EEE using different ways to introduce the fuel injection.

Methodology discourses as boundary work in the construction of engineering education.

PubMed

Beddoes, Kacey

2014-04-01

Engineering education research is a new field that emerged in the social sciences over the past 10 years. This analysis of engineering education research demonstrates that methodology discourses have played a central role in the construction and development of the field of engineering education, and that they have done so primarily through boundary work. This article thus contributes to science and technology studies literature by examining the role of methodology discourses in an emerging social science field. I begin with an overview of engineering education research before situating the case within relevant bodies of literature on methodology discourses and boundary work. I then identify two methodology discourses--rigor and methodological diversity--and discuss how they contribute to the construction and development of engineering education research. The article concludes with a discussion of how the findings relate to prior research on methodology discourses and boundary work and implications for future research.

Incorporating global components into ethics education.

PubMed

Wang, George; Thompson, Russell G

2013-03-01

Ethics is central to science and engineering. Young engineers need to be grounded in how corporate social responsibility principles can be applied to engineering organizations to better serve the broader community. This is crucial in times of climate change and ecological challenges where the vulnerable can be impacted by engineering activities. Taking a global perspective in ethics education will help ensure that scientists and engineers can make a more substantial contribution to development throughout the world. This paper presents the importance of incorporating the global and cross culture components in the ethic education. The authors bring up a question to educators on ethics education in science and engineering in the globalized world, and its importance, necessity, and impendency. The paper presents several methods for discussion that can be used to identify the differences in ethics standards and practices in different countries; enhance the student's knowledge of ethics in a global arena.

Orbital maneuvering engine feed system coupled stability investigation

NASA Technical Reports Server (NTRS)

Kahn, D. R.; Schuman, M. D.; Hunting, J. K.; Fertig, K. W.

1975-01-01

A digital computer model used to analyze and predict engine feed system coupled instabilities over a frequency range of 10 to 1000 Hz was developed and verified. The analytical approach to modeling the feed system hydrodynamics, combustion dynamics, chamber dynamics, and overall engineering model structure is described and the governing equations in each of the technical areas are presented. This is followed by a description of the generalized computer model, including formulation of the discrete subprograms and their integration into an overall engineering model structure. The operation and capabilities of the engineering model were verified by comparing the model's theoretical predictions with experimental data from an OMS-type engine with a known feed system/engine chugging history.

About opportunities of the sharing of city infrastructure centralized warmly - and water supply

NASA Astrophysics Data System (ADS)

Zamaleev, M. M.; Gubin, I. V.; Sharapov, V. I.

2017-11-01

It is shown that joint use of engineering infrastructure of centralized heat and water supply of consumers will be the cost-efficient decision for municipal services of the city. The new technology for regulated heating of drinking water in the condenser of steam turbines of combined heat and power plant is offered. Calculation of energy efficiency from application of new technology is executed.

Clocks, engines, and quarks--love, dreams, and genes. What makes development happen?

PubMed

Mayes, L C

1999-01-01

That psychological growth and maturation throughout the lifespan involve progressive linear processes is an implicit assumption of all models of development. Within psychoanalysis, a particular focus has been those processes that hinder forward development and manifest themselves as regressions or fixations or in character structure. However, the implicit assumption of progressive, linear development leaves unexplored the central question of what are the processes that govern developmental progressions. What makes psychological development happen in more or less predictable ways and yet allows for considerable individual variability? And are those developmental progressions inevitably forwardly progressive? Questions regarding what regulates and integrates development are relevant not only for understanding the normal building up of the internal world and of childhood psychopathology but also for those times of dramatic mental reorganization in adulthood surrounding events such as pregnancy and aging and for issues of psychological change during and after an analysis. Clinical material from analyses with a child and an adult and from interviews with four- to five-year-old children is used to explore individual fantasies of how development and change happens. The central role of internalization and object relations in regulating psychological development is emphasized.