Vibration attenuation of the NASA Langley evolutionary structure experiment using H(sub infinity) and structured singular value (micron) robust multivariable control techniques

NASA Technical Reports Server (NTRS)

Balas, Gary J.

1992-01-01

The use is studied of active control to attenuate structural vibrations of the NASA Langley Phase Zero Evolutionary Structure due to external disturbance excitations. H sub infinity and structured singular value (mu) based control techniques are used to analyze and synthesize control laws for the NASA Langley Controls Structures Interaction (CSI) Evolutionary Model (CEM). The CEM structure experiment provides an excellent test bed to address control design issues for large space structures. Specifically, control design for structures with numerous lightly damped, coupled flexible modes, collocated and noncollocated sensors and actuators and stringent performance specifications. The performance objectives are to attenuate the vibration of the structure due to external disturbances, and minimize the actuator control force. The control design problem formulation for the CEM Structure uses a mathematical model developed with finite element techniques. A reduced order state space model for the control design is formulated from the finite element model. It is noted that there are significant variations between the design model and the experimentally derived transfer function data.

23 CFR 625.4 - Standards, policies, and standard specifications.

Code of Federal Regulations, 2014 CFR

2014-04-01

...) Pavement Design, refer to 23 CFR part 626. (b) Bridges and structures. (1) Standard Specifications for... TRAFFIC OPERATIONS DESIGN STANDARDS FOR HIGHWAYS § 625.4 Standards, policies, and standard specifications.... (a) Roadway and appurtenances. (1) A Policy on Geometric Design of Highways and Streets, AASHTO 2001...

23 CFR 625.4 - Standards, policies, and standard specifications.

Code of Federal Regulations, 2012 CFR

2012-04-01

...) Pavement Design, refer to 23 CFR part 626. (b) Bridges and structures. (1) Standard Specifications for... TRAFFIC OPERATIONS DESIGN STANDARDS FOR HIGHWAYS § 625.4 Standards, policies, and standard specifications.... (a) Roadway and appurtenances. (1) A Policy on Geometric Design of Highways and Streets, AASHTO 2001...

23 CFR 625.4 - Standards, policies, and standard specifications.

Code of Federal Regulations, 2013 CFR

2013-04-01

...) Pavement Design, refer to 23 CFR part 626. (b) Bridges and structures. (1) Standard Specifications for... TRAFFIC OPERATIONS DESIGN STANDARDS FOR HIGHWAYS § 625.4 Standards, policies, and standard specifications.... (a) Roadway and appurtenances. (1) A Policy on Geometric Design of Highways and Streets, AASHTO 2001...

23 CFR 625.4 - Standards, policies, and standard specifications.

Code of Federal Regulations, 2010 CFR

2010-04-01

...) Pavement Design, refer to 23 CFR part 626. (b) Bridges and structures. (1) Standard Specifications for... TRAFFIC OPERATIONS DESIGN STANDARDS FOR HIGHWAYS § 625.4 Standards, policies, and standard specifications.... (a) Roadway and appurtenances. (1) A Policy on Geometric Design of Highways and Streets, AASHTO 2001...

23 CFR 625.4 - Standards, policies, and standard specifications.

Code of Federal Regulations, 2011 CFR

2011-04-01

...) Pavement Design, refer to 23 CFR part 626. (b) Bridges and structures. (1) Standard Specifications for... TRAFFIC OPERATIONS DESIGN STANDARDS FOR HIGHWAYS § 625.4 Standards, policies, and standard specifications.... (a) Roadway and appurtenances. (1) A Policy on Geometric Design of Highways and Streets, AASHTO 2001...

CRASHWORTHY TROOP SEAT INVESTIGATION

DTIC Science & Technology

1974-12-01

helicopter structure and landing gear. Newly de - signed helicopters will have landing gear designed to with- stand high sink rates and structure whioh provides...when there is no ___ ditb i- the-restrant s tystem s p§’-Hardware components sAiall carry the restraint harness design loads without permanent de ...Specification can be accepted, a troop seat design must be tested to demonstrate compliance with the proposed draft General Military Specification. Such

49 CFR 173.247 - Bulk packaging for certain elevated temperature materials.

Code of Federal Regulations, 2013 CFR

2013-10-01

... motor vehicles; and non-DOT specification cargo tank motor vehicles equivalent in structural design and...; metal IBCs and non-specification portable tanks equivalent in structural design and accident damage...; Class DOT 106, 110 multi-unit tank car tanks; AAR Class 203W, 206W, 211W tank car tanks; and non-DOT...

49 CFR 173.247 - Bulk packaging for certain elevated temperature materials.

Code of Federal Regulations, 2011 CFR

2011-10-01

... motor vehicles; and non-DOT specification cargo tank motor vehicles equivalent in structural design and...; metal IBCs and non-specification portable tanks equivalent in structural design and accident damage...; Class DOT 106, 110 multi-unit tank car tanks; AAR Class 203W, 206W, 211W tank car tanks; and non-DOT...

49 CFR 173.247 - Bulk packaging for certain elevated temperature materials.

Code of Federal Regulations, 2010 CFR

2010-10-01

... motor vehicles; and non-DOT specification cargo tank motor vehicles equivalent in structural design and...; metal IBCs and non-specification portable tanks equivalent in structural design and accident damage...; Class DOT 106, 110 multi-unit tank car tanks; AAR Class 203W, 206W, 211W tank car tanks; and non-DOT...

49 CFR 173.247 - Bulk packaging for certain elevated temperature materials.

Code of Federal Regulations, 2014 CFR

2014-10-01

... motor vehicles; and non-DOT specification cargo tank motor vehicles equivalent in structural design and...; metal IBCs and non-specification portable tanks equivalent in structural design and accident damage...; Class DOT 106, 110 multi-unit tank car tanks; AAR Class 203W, 206W, 211W tank car tanks; and non-DOT...

49 CFR 229.141 - Body structure, MU locomotives.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false Body structure, MU locomotives. 229.141 Section... Design Requirements § 229.141 Body structure, MU locomotives. (a) MU locomotives built new after April 1... body structure designed to meet or exceed the following minimum specifications: (1) The body structure...

Structure of a designed protein cage that self-assembles into a highly porous cube

DOE PAGES

Lai, Yen-Ting; Reading, Eamonn; Hura, Greg L.; ...

2014-11-10

Natural proteins can be versatile building blocks for multimeric, self-assembling structures. Yet, creating protein-based assemblies with specific geometries and chemical properties remains challenging. Highly porous materials represent particularly interesting targets for designed assembly. Here we utilize a strategy of fusing two natural protein oligomers using a continuous alpha-helical linker to design a novel protein that self assembles into a 750 kDa, 225 Å diameter, cube-shaped cage with large openings into a 130 Å diameter inner cavity. A crystal structure of the cage showed atomic level agreement with the designed model, while electron microscopy, native mass spectrometry, and small angle x-raymore » scattering revealed alternate assembly forms in solution. These studies show that accurate design of large porous assemblies with specific shapes is feasible, while further specificity improvements will likely require limiting flexibility to select against alternative forms. Finally, these results provide a foundation for the design of advanced materials with applications in bionanotechnology, nanomedicine and material sciences.« less

Modeling of additive manufacturing processes for metals: Challenges and opportunities

DOE PAGES

Francois, Marianne M.; Sun, Amy; King, Wayne E.; ...

2017-01-09

Here, with the technology being developed to manufacture metallic parts using increasingly advanced additive manufacturing processes, a new era has opened up for designing novel structural materials, from designing shapes and complex geometries to controlling the microstructure (alloy composition and morphology). The material properties used within specific structural components are also designable in order to meet specific performance requirements that are not imaginable with traditional metal forming and machining (subtractive) techniques.

Earthquake ground motion: Chapter 3

USGS Publications Warehouse

Luco, Nicolas; Kircher, Charles A.; Crouse, C. B.; Charney, Finley; Haselton, Curt B.; Baker, Jack W.; Zimmerman, Reid; Hooper, John D.; McVitty, William; Taylor, Andy

2016-01-01

Most of the effort in seismic design of buildings and other structures is focused on structural design. This chapter addresses another key aspect of the design process—characterization of earthquake ground motion into parameters for use in design. Section 3.1 describes the basis of the earthquake ground motion maps in the Provisions and in ASCE 7 (the Standard). Section 3.2 has examples for the determination of ground motion parameters and spectra for use in design. Section 3.3 describes site-specific ground motion requirements and provides example site-specific design and MCER response spectra and example values of site-specific ground motion parameters. Section 3.4 discusses and provides an example for the selection and scaling of ground motion records for use in various types of response history analysis permitted in the Standard.

Preservice and Experienced Biology Teachers' Global and Specific Subject Matter Structures: Implications for Conceptions of Pedagogical Content Knowledge

ERIC Educational Resources Information Center

Abd-El-Khalick, Fouad

2006-01-01

This study aimed to describe preservice and experienced secondary biology teachers' global and specific subject matter structures (SMSs) and elucidate the relationship between these structures and teaching experience. Teachers' global and specific SMSs respectively designate their conceptions and/or organization of their disciplines and of…

Advanced aeroservoelastic stabilization techniques for hypersonic flight vehicles

NASA Technical Reports Server (NTRS)

Chan, Samuel Y.; Cheng, Peter Y.; Myers, Thomas T.; Klyde, David H.; Magdaleno, Raymond E.; Mcruer, Duane T.

1992-01-01

Advanced high performance vehicles, including Single-Stage-To-Orbit (SSTO) hypersonic flight vehicles, that are statically unstable, require higher bandwidth flight control systems to compensate for the instability resulting in interactions between the flight control system, the engine/propulsion dynamics, and the low frequency structural modes. Military specifications, such as MIL-F-9490D and MIL-F-87242, tend to limit treatment of structural modes to conventional gain stabilization techniques. The conventional gain stabilization techniques, however, introduce low frequency effective time delays which can be troublesome from a flying qualities standpoint. These time delays can be alleviated by appropriate blending of gain and phase stabilization techniques (referred to as Hybrid Phase Stabilization or HPS) for the low frequency structural modes. The potential of using HPS for compensating structural mode interaction was previously explored. It was shown that effective time delay was significantly reduced with the use of HPS; however, the HPS design was seen to have greater residual response than a conventional gain stablized design. Additional work performed to advance and refine the HPS design procedure, to further develop residual response metrics as a basis for alternative structural stability specifications, and to develop strategies for validating HPS design and specification concepts in manned simulation is presented. Stabilization design sensitivity to structural uncertainties and aircraft-centered requirements are also assessed.

The motivations, institutions and organization of university-industry collaborations in the Netherlands.

PubMed

Bodas Freitas, Isabel Maria; Verspagen, Bart

2017-01-01

This study builds on the economics and organization literatures to explore whether and how institutions and organizational structure complement or substitute each other to create specific spaces of alignment where specific individual actors' motivations co-exist. Focusing on university-industry collaborations, the study examines whether and how different axes of alignment of university and industry motivations are integrated in projects with specific technological objectives and organizational structures, benefitting from the presence of specific institutions designed to facilitate collaboration. Empirically, the study relies on in-depth data on 30 university-industry collaborations in the Netherlands, and provides preliminary evidence that the technological objective and organizational structure of collaboration are malleable variables allowing the integration of both partners' objectives and expectations. Different institutional incentives for university-industry collaboration favor specific axes of alignment of motivations and certain types of collaborative projects' design. Hence, our exploratory results suggest that specific organizational and technological structures tend to prevail in the presence of specific institutions.

Miscellaneous wood structures

Treesearch

Michael A. Ritter; Keith F. Faherty

1999-01-01

This section addresses the design of two types of glulam timber bridges : beam bridges with transverse decks and longitudinal glulam deck (slab) bridges. The material presented in the section is based on the 1992 edition of the AASHTO Standard Specifications for Highway Bridges (AASHTO specifications), including interim specifications through 1993. When specific design...

Structure based re-design of the binding specificity of anti-apoptotic Bcl-xL

PubMed Central

Chen, T. Scott; Palacios, Hector; Keating, Amy E.

2012-01-01

Many native proteins are multi-specific and interact with numerous partners, which can confound analysis of their functions. Protein design provides a potential route to generating synthetic variants of native proteins with more selective binding profiles. Re-designed proteins could be used as research tools, diagnostics or therapeutics. In this work, we used a library screening approach to re-engineer the multi-specific anti-apoptotic protein Bcl-xL to remove its interactions with many of its binding partners, making it a high affinity and selective binder of the BH3 region of pro-apoptotic protein Bad. To overcome the enormity of the potential Bcl-xL sequence space, we developed and applied a computational/experimental framework that used protein structure information to generate focused combinatorial libraries. Sequence features were identified using structure-based modeling, and an optimization algorithm based on integer programming was used to select degenerate codons that maximally covered these features. A constraint on library size was used to ensure thorough sampling. Using yeast surface display to screen a designed library of Bcl-xL variants, we successfully identified a protein with ~1,000-fold improvement in binding specificity for the BH3 region of Bad over the BH3 region of Bim. Although negative design was targeted only against the BH3 region of Bim, the best re-designed protein was globally specific against binding to 10 other peptides corresponding to native BH3 motifs. Our design framework demonstrates an efficient route to highly specific protein binders and may readily be adapted for application to other design problems. PMID:23154169

Modeling and Design Analysis Methodology for Tailoring of Aircraft Structures with Composites

NASA Technical Reports Server (NTRS)

Rehfield, Lawrence W.

2004-01-01

Composite materials provide design flexibility in that fiber placement and orientation can be specified and a variety of material forms and manufacturing processes are available. It is possible, therefore, to 'tailor' the structure to a high degree in order to meet specific design requirements in an optimum manner. Common industrial practices, however, have limited the choices designers make. One of the reasons for this is that there is a dearth of conceptual/preliminary design analysis tools specifically devoted to identifying structural concepts for composite airframe structures. Large scale finite element simulations are not suitable for such purposes. The present project has been devoted to creating modeling and design analysis methodology for use in the tailoring process of aircraft structures. Emphasis has been given to creating bend-twist elastic coupling in high aspect ratio wings or other lifting surfaces. The direction of our work was in concert with the overall NASA effort Twenty- First Century Aircraft Technology (TCAT). A multi-disciplinary team was assembled by Dr. Damodar Ambur to work on wing technology, which included our project.

Structural Testing at the NWTC Helps Improve Blade Design and Increase System Reliability; NREL (National Renewable Energy Laboratory)

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

None

2015-08-01

Since 1990, the National Renewable Energy Laboratory’s (NREL's) National Wind Technology Center (NWTC) has tested more than 150 wind turbine blades. NWTC researchers can test full-scale and subcomponent articles, conduct data analyses, and provide engineering expertise on best design practices. Structural testing of wind turbine blades enables designers, manufacturers, and owners to validate designs and assess structural performance to specific load conditions. Rigorous structural testing can reveal design and manufacturing problems at an early stage of development that can lead to overall improvements in design and increase system reliability.

Shuttle/TDRSS Ku-band downlink study

NASA Technical Reports Server (NTRS)

Meyer, R.

1976-01-01

Assessing the adequacy of the baseline signal design approach, developing performance specifications for the return link hardware, and performing detailed design and parameter optimization tasks was accomplished by completing five specific study tasks. The results of these tasks show that the basic signal structure design is sound and that the goals can be met. Constraints placed on return link hardware by this structure allow reasonable specifications to be written so that no extreme technical risk areas in equipment design are foreseen. A third channel can be added to the PM mode without seriously degrading the other services. The feasibility of using only a PM mode was shown to exist, however, this will require use of some digital TV transmission techniques. Each task and its results are summarized.

Design concepts for a composite door frame system for general automotive applications

NASA Technical Reports Server (NTRS)

Tauber, J. A.

1976-01-01

Conceptual design, manufacturing process, and costs are explored to determine the feasibility of replacing present steel parts in automotive door structures with various composite materials. The problems of conforming to present anti-intrusion specifications with advanced materials are examined and discussed. Modest weight reductions, at competitive costs, were identified for the utilization of specific composite materials in automotive door structures.

DNA Origami Patterned Colloids for Programmed Design and Chirality

NASA Astrophysics Data System (ADS)

Ben Zion, Matan Yah; He, Xiaojin; Maass, Corinna; Sha, Ruojie; Seeman, Ned; Chaikin, Paul

Micron size colloidal particles are scientifically important as model systems for equilibrium and active systems in physics, chemistry and biology and for technologies ranging from catalysis to photonics. The past decade has seen development of new particles with directional patches, lock and key reactions and specific recognition that guide assembly of structures such as complex crystalline arrays. What remains lacking is the ability to self-assemble structures of arbitrary shape with specific chirality, placement and orientation of neighbors. Here we demonstrate the adaptation of DNA origami nanotechnology to the micron colloidal scale with designed control of neighbor type, placement and dihedral angle. We use DNA origami belts with programmed flexibility, and functionality to pattern colloidal surfaces and bind particles to specific sites at specific angles and make uniquely right handed or left handed structures. The hybrid DNA origami colloid technology should allow the synthesis of designed functional structural and active materials. This work was supported as part of the Center for Bio-Inspired Energy Science, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences under Award # DE-SC0000989.

Structural modeling for multicell composite rotor blades

NASA Technical Reports Server (NTRS)

Rehfield, Lawrence W.; Atilgan, Ali R.

1987-01-01

Composite material systems are currently good candidates for aerospace structures, primarily for the design flexibility they offer, i.e., it is possible to tailor the material and manufacturing approach to the application. A working definition of elastic or structural tailoring is the use of structural concept, fiber orientation, ply stacking sequence, and a blend of materials to achieve specific performance goals. In the design process, choices of materials and dimensions are made which produce specific response characteristics, and which permit the selected goals to be achieved. Common choices for tailoring goals are preventing instabilities or vibration resonances or enhancing damage tolerance. An essential, enabling factor in the design of tailored composite structures is structural modeling that accurately, but simply, characterizes response. The objective of this paper is to present a new multicell beam model for composite rotor blades and to validate predictions based on the new model by comparison with a finite element simulation in three benchmark static load cases.

Quantification of the transferability of a designed protein specificity switch reveals extensive epistasis in molecular recognition

DOE PAGES

Melero, Cristina; Ollikainen, Noah; Harwood, Ian; ...

2014-10-13

Re-engineering protein–protein recognition is an important route to dissecting and controlling complex interaction networks. Experimental approaches have used the strategy of “second-site suppressors,” where a functional interaction is inferred between two proteins if a mutation in one protein can be compensated by a mutation in the second. Mimicking this strategy, computational design has been applied successfully to change protein recognition specificity by predicting such sets of compensatory mutations in protein–protein interfaces. To extend this approach, it would be advantageous to be able to “transplant” existing engineered and experimentally validated specificity changes to other homologous protein–protein complexes. Here, we test thismore » strategy by designing a pair of mutations that modulates peptide recognition specificity in the Syntrophin PDZ domain, confirming the designed interaction biochemically and structurally, and then transplanting the mutations into the context of five related PDZ domain–peptide complexes. We find a wide range of energetic effects of identical mutations in structurally similar positions, revealing a dramatic context dependence (epistasis) of designed mutations in homologous protein–protein interactions. To better understand the structural basis of this context dependence, we apply a structure-based computational model that recapitulates these energetic effects and we use this model to make and validate forward predictions. The context dependence of these mutations is captured by computational predictions, our results both highlight the considerable difficulties in designing protein–protein interactions and provide challenging benchmark cases for the development of improved protein modeling and design methods that accurately account for the context.« less

Quantification of the transferability of a designed protein specificity switch reveals extensive epistasis in molecular recognition

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

Melero, Cristina; Ollikainen, Noah; Harwood, Ian

Re-engineering protein–protein recognition is an important route to dissecting and controlling complex interaction networks. Experimental approaches have used the strategy of “second-site suppressors,” where a functional interaction is inferred between two proteins if a mutation in one protein can be compensated by a mutation in the second. Mimicking this strategy, computational design has been applied successfully to change protein recognition specificity by predicting such sets of compensatory mutations in protein–protein interfaces. To extend this approach, it would be advantageous to be able to “transplant” existing engineered and experimentally validated specificity changes to other homologous protein–protein complexes. Here, we test thismore » strategy by designing a pair of mutations that modulates peptide recognition specificity in the Syntrophin PDZ domain, confirming the designed interaction biochemically and structurally, and then transplanting the mutations into the context of five related PDZ domain–peptide complexes. We find a wide range of energetic effects of identical mutations in structurally similar positions, revealing a dramatic context dependence (epistasis) of designed mutations in homologous protein–protein interactions. To better understand the structural basis of this context dependence, we apply a structure-based computational model that recapitulates these energetic effects and we use this model to make and validate forward predictions. The context dependence of these mutations is captured by computational predictions, our results both highlight the considerable difficulties in designing protein–protein interactions and provide challenging benchmark cases for the development of improved protein modeling and design methods that accurately account for the context.« less

29 CFR 1910.66 - Powered platforms for building maintenance.

Code of Federal Regulations, 2012 CFR

2012-07-01

... roof socket or carriage attachment. Equivalent means alternative designs, materials or methods which... that the equipment is designed to support. Obstruction detector means a control that will stop the... scaffold is not designed for use on a specific structure or group of structures. Tail line means the...

29 CFR 1910.66 - Powered platforms for building maintenance.

Code of Federal Regulations, 2011 CFR

2011-07-01

... roof socket or carriage attachment. Equivalent means alternative designs, materials or methods which... that the equipment is designed to support. Obstruction detector means a control that will stop the... scaffold is not designed for use on a specific structure or group of structures. Tail line means the...

40 CFR 165.85 - Design and capacity requirements for new structures.

Code of Federal Regulations, 2011 CFR

2011-07-01

... containment structures: (1) You must protect appurtenances and pesticide containers against damage from... stationary containers of liquid pesticides, what are the specific design requirements? You must either anchor... 40 Protection of Environment 24 2011-07-01 2011-07-01 false Design and capacity requirements for...

40 CFR 165.85 - Design and capacity requirements for new structures.

Code of Federal Regulations, 2013 CFR

2013-07-01

... containment structures: (1) You must protect appurtenances and pesticide containers against damage from... stationary containers of liquid pesticides, what are the specific design requirements? You must either anchor... 40 Protection of Environment 25 2013-07-01 2013-07-01 false Design and capacity requirements for...

40 CFR 165.85 - Design and capacity requirements for new structures.

Code of Federal Regulations, 2014 CFR

2014-07-01

... containment structures: (1) You must protect appurtenances and pesticide containers against damage from... stationary containers of liquid pesticides, what are the specific design requirements? You must either anchor... 40 Protection of Environment 24 2014-07-01 2014-07-01 false Design and capacity requirements for...

40 CFR 165.85 - Design and capacity requirements for new structures.

Code of Federal Regulations, 2012 CFR

2012-07-01

... containment structures: (1) You must protect appurtenances and pesticide containers against damage from... stationary containers of liquid pesticides, what are the specific design requirements? You must either anchor... 40 Protection of Environment 25 2012-07-01 2012-07-01 false Design and capacity requirements for...

Structural design parameters of current WSDOT mixtures.

DOT National Transportation Integrated Search

2013-06-01

The AASHTO LRFD, as well as other design manuals, has specifications that estimate the structural performance of a concrete mixture with regard to compressive strength, tensile strength, and deformation-related properties such as the modulus of elast...

Ligand binding by repeat proteins: natural and designed

PubMed Central

Grove, Tijana Z; Cortajarena, Aitziber L; Regan, Lynne

2012-01-01

Repeat proteins contain tandem arrays of small structural motifs. As a consequence of this architecture, they adopt non-globular, extended structures that present large, highly specific surfaces for ligand binding. Here we discuss recent advances toward understanding the functional role of this unique modular architecture. We showcase specific examples of natural repeat proteins interacting with diverse ligands and also present examples of designed repeat protein–ligand interactions. PMID:18602006

Selected approaches for rational drug design and high throughput screening to identify anti-cancer molecules.

PubMed

Hedvat, Michael; Emdad, Luni; Das, Swadesh K; Kim, Keetae; Dasgupta, Santanu; Thomas, Shibu; Hu, Bin; Zhu, Shan; Dash, Rupesh; Quinn, Bridget A; Oyesanya, Regina A; Kegelman, Timothy P; Sokhi, Upneet K; Sarkar, Siddik; Erdogan, Eda; Menezes, Mitchell E; Bhoopathi, Praveen; Wang, Xiang-Yang; Pomper, Martin G; Wei, Jun; Wu, Bainan; Stebbins, John L; Diaz, Paul W; Reed, John C; Pellecchia, Maurizio; Sarkar, Devanand; Fisher, Paul B

2012-11-01

Structure-based modeling combined with rational drug design, and high throughput screening approaches offer significant potential for identifying and developing lead compounds with therapeutic potential. The present review focuses on these two approaches using explicit examples based on specific derivatives of Gossypol generated through rational design and applications of a cancer-specificpromoter derived from Progression Elevated Gene-3. The Gossypol derivative Sabutoclax (BI-97C1) displays potent anti-tumor activity against a diverse spectrum of human tumors. The model of the docked structure of Gossypol bound to Bcl-XL provided a virtual structure-activity-relationship where appropriate modifications were predicted on a rational basis. These structure-based studies led to the isolation of Sabutoclax, an optically pure isomer of Apogossypol displaying superior efficacy and reduced toxicity. These studies illustrate the power of combining structure-based modeling with rational design to predict appropriate derivatives of lead compounds to be empirically tested and evaluated for bioactivity. Another approach to cancer drug discovery utilizes a cancer-specific promoter as readouts of the transformed state. The promoter region of Progression Elevated Gene-3 is such a promoter with cancer-specific activity. The specificity of this promoter has been exploited as a means of constructing cancer terminator viruses that selectively kill cancer cells and as a systemic imaging modality that specifically visualizes in vivo cancer growth with no background from normal tissues. Screening of small molecule inhibitors that suppress the Progression Elevated Gene-3-promoter may provide relevant lead compounds for cancer therapy that can be combined with further structure-based approaches leading to the development of novel compounds for cancer therapy.

Structured output-feedback controller synthesis with design specifications

NASA Astrophysics Data System (ADS)

Hao, Yuqing; Duan, Zhisheng

2017-03-01

This paper considers the problem of structured output-feedback controller synthesis with finite frequency specifications. Based on the orthogonal space information of input matrix, an improved parameter-dependent Lyapunov function method is first proposed. Then, a two-stage construction method is designed, which depends on an initial centralised controller. Corresponding design conditions for three types of output-feedback controllers are presented in terms of unified representations. Moreover, heuristic algorithms are provided to explore the desirable controllers. Finally, the effectiveness of these proposed methods is illustrated via some practical examples.

Design considerations for composite fuselage structure of commercial transport aircraft

NASA Technical Reports Server (NTRS)

Davis, G. W.; Sakata, I. F.

1981-01-01

The structural, manufacturing, and service and environmental considerations that could impact the design of composite fuselage structure for commercial transport aircraft application were explored. The severity of these considerations was assessed and the principal design drivers delineated. Technical issues and potential problem areas which must be resolved before sufficient confidence is established to commit to composite materials were defined. The key issues considered are: definition of composite fuselage design specifications, damage tolerance, and crashworthiness.

Structural and compositional features of high-rise buildings: experimental design in Yekaterinburg

NASA Astrophysics Data System (ADS)

Yankovskaya, Yulia; Lobanov, Yuriy; Temnov, Vladimir

2018-03-01

The study looks at the specifics of high-rise development in Yekaterinburg. High-rise buildings are considered in the context of their historical development, structural features, compositional and imaginative design techniques. Experience of Yekaterinburg architects in experimental design is considered and analyzed. Main issues and prospects of high-rise development within the Yekaterinburg structure are studied. The most interesting and significant conceptual approaches to the structural and compositional arrangement of high-rise buildings are discussed.

The Specification of Causal Models with Tetrad IV: A Review

ERIC Educational Resources Information Center

Landsheer, J. A.

2010-01-01

Tetrad IV is a program designed for the specification of causal models. It is specifically designed to search for causal relations, but also offers the possibility to estimate the parameters of a structural equation model. It offers a remarkable graphical user interface, which facilitates building, evaluating, and searching for causal models. The…

26 CFR 1.48-10 - Single purpose agricultural or horticultural structures.

Code of Federal Regulations, 2010 CFR

2010-04-01

... designed and constructed” test of paragraph (d) of this section since it would be economic to use the... specifically designed and constructed for permissible purposes (as defined in paragraph (b)(2) of this section). See paragraph (d) of this section for the rule regarding “specifically designed and constructed”. (ii...

26 CFR 1.48-10 - Single purpose agricultural or horticultural structures.

Code of Federal Regulations, 2011 CFR

2011-04-01

... designed and constructed” test of paragraph (d) of this section since it would be economic to use the... specifically designed and constructed for permissible purposes (as defined in paragraph (b)(2) of this section). See paragraph (d) of this section for the rule regarding “specifically designed and constructed”. (ii...

Behavior and design of large structural concrete bridge pier overhangs.

DOT National Transportation Integrated Search

1997-02-01

In designing large cantilever bent caps for use on recent projects under current AASHTO design specifications, : designers were faced with considerable uncertainties. Questions arose when designers attempted to satisfy : both serviceability and stren...

30 CFR 77.216-5 - Water, sediment or slurry impoundments and impounding structures; abandonment.

Code of Federal Regulations, 2010 CFR

2010-07-01

... are met: (1) A registered professional engineer, knowledgeable in the principles of dam design and in the design and construction of the structure, shall certify that it substantially conforms to the approved design plan and specifications and that there are no apparent defects. (2) The current owner or...

30 CFR 77.216-5 - Water, sediment or slurry impoundments and impounding structures; abandonment.

Code of Federal Regulations, 2011 CFR

2011-07-01

... are met: (1) A registered professional engineer, knowledgeable in the principles of dam design and in the design and construction of the structure, shall certify that it substantially conforms to the approved design plan and specifications and that there are no apparent defects. (2) The current owner or...

Purdue Plane Structures Analyzer II : a computerized wood engineering system

Treesearch

S. K. Suddarth; R. W. Wolfe

1984-01-01

The Purdue Plane Structures Analyzer (PPSA) is a computer program developed specifically for the analysis of wood structures. It uses recognized analysis procedures, in conjunction with recommendations of the 1982 National Design Specification for Wood Construction, to determine stresses and deflections of wood trusses and frames. The program offers several options for...

Liquid-phase tuning of porous PVDF-TrFE film on flexible substrate for energy harvesting

NASA Astrophysics Data System (ADS)

Chen, Dajing; Chen, Kaina; Brown, Kristopher; Hang, Annie; Zhang, John X. J.

2017-04-01

Emerging wearable and implantable biomedical energy harvesting devices demand efficient power conversion, flexible structures, and lightweight construction. This paper presents Polyvinylidene fluoride-trifluoroethylene (PVDF-TrFE) micro-porous structures, which can be tuned to specific mechanical flexibilities and optimized for piezoelectric power conversion. Specifically, the water vapor phase separation method was developed to control microstructure formation, pore diameter, porosity, and mechanical flexibility. Furthermore, we investigated the effects of the piezoelectric layer to supporting layer Young's modulus ratio, through using both analytical calculation and experimentation. Both structure flexibility and stress-induced voltage were considered in the analyses. Specification of electromechanical coupling efficiency, made possible by carefully designed three-dimensional porous structures, was shown to increase the power output by five-fold relative to uncoupled structures. Therefore, flexible PVDF-TrFE films with tunable microstructures, paired with substrates of different rigidities, provide highly efficient designs of compact piezoelectric energy generating devices.

Structural basis of substrate specificity in the serine proteases.

PubMed Central

Perona, J. J.; Craik, C. S.

1995-01-01

Structure-based mutational analysis of serine protease specificity has produced a large database of information useful in addressing biological function and in establishing a basis for targeted design efforts. Critical issues examined include the function of water molecules in providing strength and specificity of binding, the extent to which binding subsites are interdependent, and the roles of polypeptide chain flexibility and distal structural elements in contributing to specificity profiles. The studies also provide a foundation for exploring why specificity modification can be either straightforward or complex, depending on the particular system. PMID:7795518

Technology update: Tethered aerostat structural design and material developments

NASA Technical Reports Server (NTRS)

Witherow, R. G.

1975-01-01

Requirements exist for an extremely stable, high performance, all-weather tethered aerostat system. This requirement has been satisfied by a 250,000 cubic foot captive buoyant vehicle as demonstrated by over a year of successful field operations. This achievement required significant advancements in several technology areas including composite materials design, aerostatics and aerodynamics, structural design, electro-mechanical design, vehicle fabrication and mooring operations. This paper specifically addresses the materials and structural design aspects of pressurized buoyant vehicles as related to the general class of Lighter Than Air vehicles.

Structure based design of 11β-HSD1 inhibitors.

PubMed

Singh, Suresh; Tice, Colin

2010-11-01

Controlling elevated tissue-specific levels of cortisol may provide a novel therapeutic approach for treating metabolic syndrome. This concept has spurred large scale medicinal chemistry efforts in the pharmaceutical industry for the design of 11β-HSD1 inhibitors. High resolution X-ray crystal structures of inhibitors in complex with the enzyme have facilitated the structure-based design of diverse classes of molecules. A summary of binding modes, trends in structure-activity relationships, and the pharmacodynamic data of inhibitors from each class is presented.

Modeled structure of trypanothione reductase of Leishmania infantum.

PubMed

Singh, Bishal K; Sarkar, Nandini; Jagannadham, M V; Dubey, Vikash K

2008-06-30

Trypanothione reductase is an important target enzyme for structure-based drug design against Leishmania. We used homology modeling to construct a three-dimensional structure of the trypanothione reductase (TR) of Leishmania infantum. The structure shows acceptable Ramachandran statistics and a remarkably different active site from glutathione reductase(GR). Thus, a specific inhibitor against TR can be designed without interfering with host (human) GR activity.

Matrix Transfer Function Design for Flexible Structures: An Application

NASA Technical Reports Server (NTRS)

Brennan, T. J.; Compito, A. V.; Doran, A. L.; Gustafson, C. L.; Wong, C. L.

1985-01-01

The application of matrix transfer function design techniques to the problem of disturbance rejection on a flexible space structure is demonstrated. The design approach is based on parameterizing a class of stabilizing compensators for the plant and formulating the design specifications as a constrained minimization problem in terms of these parameters. The solution yields a matrix transfer function representation of the compensator. A state space realization of the compensator is constructed to investigate performance and stability on the nominal and perturbed models. The application is made to the ACOSSA (Active Control of Space Structures) optical structure.

Aerospace Structures Technology Damping Design Guide. Volume 1. Technology Review

DTIC Science & Technology

1985-12-01

AFWAL-TR-84-3089 Volume I AEROSPACE STRUCTURES TECHNOLOGY I DAMPING DESIGN GUIDE VOLUME I - TECHNOLOGY REVIEW J. SOOVERE LOCKHEED CALIFORNIA COMPANY...3089 Volume I AEROSPACE STRUCTURES TECHNOLOGY DAMPING DESIGN GUIDE VOLUME I - TECHNOLOGY REVIEW J. SOOVERE LOCKMD CALIFORNIA COMPANY P.O. BOX 551 BURBANK...PATTERSON AIR FORCE BASE, OHIO 454t33I I ft NOTICE When Government drawings, specifications, or other data are used for any purpose other than in

Interdisciplinary optimum design. [of aerospace structures

NASA Technical Reports Server (NTRS)

Sobieszczanski-Sobieski, Jaroslaw; Haftka, Raphael T.

1986-01-01

Problems related to interdisciplinary interactions in the design of a complex engineering systems are examined with reference to aerospace applications. The interdisciplinary optimization problems examined include those dealing with controls and structures, materials and structures, control and stability, structure and aerodynamics, and structure and thermodynamics. The discussion is illustrated by the following specific applications: integrated aerodynamic/structural optimization of glider wing; optimization of an antenna parabolic dish structure for minimum weight and prescribed emitted signal gain; and a multilevel optimization study of a transport aircraft.

Structure of Insoluble Rat Sperm Glyceraldehyde-3-phosphate Dehydrogenase (GAPDH) via Heterotetramer Formation with Escherichia coli GAPDH Reveals Target for Contraceptive Design*

PubMed Central

Frayne, Jan; Taylor, Abby; Cameron, Gus; Hadfield, Andrea T.

2009-01-01

Sperm glyceraldehyde-3-phosphate dehydrogenase has been shown to be a successful target for a non-hormonal contraceptive approach, but the agents tested to date have had unacceptable side effects. Obtaining the structure of the sperm-specific isoform to allow rational inhibitor design has therefore been a goal for a number of years but has proved intractable because of the insoluble nature of both native and recombinant protein. We have obtained soluble recombinant sperm glyceraldehyde-3-phosphate dehydrogenase as a heterotetramer with the Escherichia coli glyceraldehyde-3-phosphate dehydrogenase in a ratio of 1:3 and have solved the structure of the heterotetramer which we believe represents a novel strategy for structure determination of an insoluble protein. A structure was also obtained where glyceraldehyde 3-phosphate binds in the Ps pocket in the active site of the sperm enzyme subunit in the presence of NAD. Modeling and comparison of the structures of human somatic and sperm-specific glyceraldehyde-3-phosphate dehydrogenase revealed few differences at the active site and hence rebut the long presumed structural specificity of 3-chlorolactaldehyde for the sperm isoform. The contraceptive activity of α-chlorohydrin and its apparent specificity for the sperm isoform in vivo are likely to be due to differences in metabolism to 3-chlorolactaldehyde in spermatozoa and somatic cells. However, further detailed analysis of the sperm glyceraldehyde-3-phosphate dehydrogenase structure revealed sites in the enzyme that do show significant difference compared with published somatic glyceraldehyde-3-phosphate dehydrogenase structures that could be exploited by structure-based drug design to identify leads for novel male contraceptives. PMID:19542219

Feasibility study of an Integrated Program for Aerospace vehicle Design (IPAD). Volume 4: IPAD system design

NASA Technical Reports Server (NTRS)

Goldfarb, W.; Carpenter, L. C.; Redhed, D. D.; Hansen, S. D.; Anderson, L. O.; Kawaguchi, A. S.

1973-01-01

The computing system design of IPAD is described and the requirements which form the basis for the system design are discussed. The system is presented in terms of a functional design description and technical design specifications. The functional design specifications give the detailed description of the system design using top-down structured programming methodology. Human behavioral characteristics, which specify the system design at the user interface, security considerations, and standards for system design, implementation, and maintenance are also part of the technical design specifications. Detailed specifications of the two most common computing system types in use by the major aerospace companies which could support the IPAD system design are presented. The report of a study to investigate migration of IPAD software between the two candidate 3rd generation host computing systems and from these systems to a 4th generation system is included.

Calibration of the live load factor in LRFD design guidelines.

DOT National Transportation Integrated Search

2010-09-01

The Load and Resistant Factor Design (LRFD) approach is based on the concept of structural reliability. The approach is : more rational than the former design approaches such as Load Factor Design or Allowable Stress Design. The LRFD : Specification ...

Calibration of the live load factor in LRFD design guidelines : [revised].

DOT National Transportation Integrated Search

2011-07-01

The Load and Resistant Factor Design (LRFD) approach is based on the concept of structural reliability. The approach is : more rational than the former design approaches such as Load Factor Design or Allowable Stress Design. The LRFD : Specification ...

49 CFR 179.300 - General specifications applicable to multi-unit tank car tanks designed to be removed from car...

Code of Federal Regulations, 2012 CFR

2012-10-01

... tank car tanks designed to be removed from car structure for filling and emptying (Classes DOT-106A and...) PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) SPECIFICATIONS FOR TANK CARS Specifications for Multi-Unit Tank Car Tanks (Classes DOT-106A and 110AW) § 179.300...

49 CFR 179.300 - General specifications applicable to multi-unit tank car tanks designed to be removed from car...

Code of Federal Regulations, 2011 CFR

2011-10-01

... tank car tanks designed to be removed from car structure for filling and emptying (Classes DOT-106A and...) PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) SPECIFICATIONS FOR TANK CARS Specifications for Multi-Unit Tank Car Tanks (Classes DOT-106A and 110AW) § 179.300...

Fatigue in aerostructures--where structural health monitoring can contribute to a complex subject.

PubMed

Boller, Christian; Buderath, Matthias

2007-02-15

An overview of the aircraft design and maintenance process is given with specific emphasis on the fatigue design as well as the phenomenon of the ageing aircraft observed over the life cycle. The different measures taken to guarantee structural integrity along the maintenance process are addressed. The impact of structural health monitoring as a means of possibly revolutionizing the current aircraft structural monitoring and design process is emphasized and comparison is made to jet engines and helicopters, where health monitoring has already found the respective breakthrough.

Structural considerations in design of lightweight glass-fiber composite pressure vessels

NASA Technical Reports Server (NTRS)

Faddoul, J. R.

1973-01-01

The development of structurally efficient, metal-lined, glass-fiber composite pressure vessels. Both the current state-of-the-art and current problems are discussed along with fracture mechanics considerations for the metal liner. The design concepts used for metal-lined, glass-fiber, composite pressure vessels are described and the structural characteristics of the composite designs are compared with each other and with homogeneous metal pressure vessels. Specific design techniques and available design data are identified. Results of a current program to evaluate flaw growth and fracture characteristics of the metal liners are reviewed and the impact of these results on composite pressure vessel designs is discussed.

Composite structural materials. [aircraft applications

NASA Technical Reports Server (NTRS)

Ansell, G. S.; Loewy, R. G.; Wiberley, S. E.

1981-01-01

The development of composite materials for aircraft applications is addressed with specific consideration of physical properties, structural concepts and analysis, manufacturing, reliability, and life prediction. The design and flight testing of composite ultralight gliders is documented. Advances in computer aided design and methods for nondestructive testing are also discussed.

Conceptual design and structural analysis for an 8.4-m telescope

NASA Astrophysics Data System (ADS)

Mendoza, Manuel; Farah, Alejandro; Ruiz Schneider, Elfego

2004-09-01

This paper describes the conceptual design of the optics support structures of a telescope with a primary mirror of 8.4 m, the same size as a Large Binocular Telescope (LBT) primary mirror. The design goal is to achieve a structure for supporting the primary and secondary mirrors and keeping them joined as rigid as possible. With this purpose an optimization with several models was done. This iterative design process includes: specifications development, concepts generation and evaluation. Process included Finite Element Analysis (FEA) as well as other analytical calculations. Quality Function Deployment (QFD) matrix was used to obtain telescope tube and spider specifications. Eight spiders and eleven tubes geometric concepts were proposed. They were compared in decision matrixes using performance indicators and parameters. Tubes and spiders went under an iterative optimization process. The best tubes and spiders concepts were assembled together. All assemblies were compared and ranked according to their performance.

Biomaterials Made from Coiled-Coil Peptides.

PubMed

Conticello, Vincent; Hughes, Spencer; Modlin, Charles

The development of biomaterials designed for specific applications is an important objective in personalized medicine. While the breadth and prominence of biomaterials have increased exponentially over the past decades, critical challenges remain to be addressed, particularly in the development of biomaterials that exhibit highly specific functions. These functional properties are often encoded within the molecular structure of the component molecules. Proteins, as a consequence of their structural specificity, represent useful substrates for the construction of functional biomaterials through rational design. This chapter provides an in-depth survey of biomaterials constructed from coiled-coils, one of the best-understood protein structural motifs. We discuss the utility of this structurally diverse and functionally tunable class of proteins for the creation of novel biomaterials. This discussion illustrates the progress that has been made in the development of coiled-coil biomaterials by showcasing studies that bridge the gap between the academic science and potential technological impact.

A three-dimensional actuated origami-inspired transformable metamaterial with multiple degrees of freedom

NASA Astrophysics Data System (ADS)

Overvelde, Johannes T. B.; de Jong, Twan A.; Shevchenko, Yanina; Becerra, Sergio A.; Whitesides, George M.; Weaver, James C.; Hoberman, Chuck; Bertoldi, Katia

2016-03-01

Reconfigurable devices, whose shape can be drastically altered, are central to expandable shelters, deployable space structures, reversible encapsulation systems and medical tools and robots. All these applications require structures whose shape can be actively controlled, both for deployment and to conform to the surrounding environment. While most current reconfigurable designs are application specific, here we present a mechanical metamaterial with tunable shape, volume and stiffness. Our approach exploits a simple modular origami-like design consisting of rigid faces and hinges, which are connected to form a periodic structure consisting of extruded cubes. We show both analytically and experimentally that the transformable metamaterial has three degrees of freedom, which can be actively deformed into numerous specific shapes through embedded actuation. The proposed metamaterial can be used to realize transformable structures with arbitrary architectures, highlighting a robust strategy for the design of reconfigurable devices over a wide range of length scales.

Crystal structure of a designed, thermostable, heterotrimeric coiled coil.

PubMed Central

Nautiyal, S.; Alber, T.

1999-01-01

Electrostatic interactions are often critical for determining the specificity of protein-protein complexes. To study the role of electrostatic interactions for assembly of helical bundles, we previously designed a thermostable, heterotrimeric coiled coil, ABC, in which charged residues were employed to drive preferential association of three distinct, 34-residue helices. To investigate the basis for heterotrimer specificity, we have used multiwavelength anomalous diffraction (MAD) analysis to determine the 1.8 A resolution crystal structure of ABC. The structure shows that ABC forms a heterotrimeric coiled coil with the intended arrangement of parallel chains. Over half of the ion pairs engineered to restrict helix associations were apparent in the experimental electron density map. As seen in other trimeric coiled coils, ABC displays acute knobs-into-holes packing and a buried anion coordinated by core polar amino acids. These interactions validate the design strategy and illustrate how packing and polar contacts determine structural uniqueness. PMID:10210186

The Design Log: A New Informational Tool

ERIC Educational Resources Information Center

Spivak, Mayer

1978-01-01

The design log is a record of observations, diagnoses, prescriptions, and performance specifications for each space in a structure. It is a systematic approach to design that integrates information about user needs with traditional architectural programming and design. (Author/MLF)

Design criteria monograph on turbopump inducers

NASA Technical Reports Server (NTRS)

1972-01-01

State of the art and design criteria for liquid rocket engine turbopump inducers are summarized for optimal fabrication. Design criteria optimize hydrodynamic parameters to obtain highest suction specific speed without violating structural and mechanical constraints.

Rapid Assessment of Aircraft Structural Topologies for Multidisciplinary Optimization and Weight Estimation

NASA Technical Reports Server (NTRS)

Samareh, Jamshid A.; Sensmeier, mark D.; Stewart, Bret A.

2006-01-01

Algorithms for rapid generation of moderate-fidelity structural finite element models of air vehicle structures to allow more accurate weight estimation earlier in the vehicle design process have been developed. Application of these algorithms should help to rapidly assess many structural layouts before the start of the preliminary design phase and eliminate weight penalties imposed when actual structure weights exceed those estimated during conceptual design. By defining the structural topology in a fully parametric manner, the structure can be mapped to arbitrary vehicle configurations being considered during conceptual design optimization. Recent enhancements to this approach include the porting of the algorithms to a platform-independent software language Python, and modifications to specifically consider morphing aircraft-type configurations. Two sample cases which illustrate these recent developments are presented.

Designing a new structure for storing nuclear data: Progress of the Working Party for Evaluation Cooperation subgroup #38

DOE PAGES

Mattoon, C. M.; Beck, B. R.

2015-12-24

An international effort is underway to design a new structure for storing and using nuclear reaction data, with the goal of eventually replacing the current standard, ENDF-6. This effort, organized by the Working Party for Evaluation Cooperation, was initiated in 2012 and has resulted in a list of requirements and specifications for how the proposed new structure shall perform. The new structure will take advantage of new developments in computational tools, using a nested hierarchy to store data. Here, the structure can be stored in text form (such as an XML file) for human readability and data sharing, or itmore » can be stored in binary to optimize data access. In this paper, we present the progress towards completing the requirements, specifications and implementation of the new structure.« less

Designing a new structure for storing nuclear data: Progress of the Working Party for Evaluation Cooperation subgroup #38

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

Mattoon, C. M.; Beck, B. R.

An international effort is underway to design a new structure for storing and using nuclear reaction data, with the goal of eventually replacing the current standard, ENDF-6. This effort, organized by the Working Party for Evaluation Cooperation, was initiated in 2012 and has resulted in a list of requirements and specifications for how the proposed new structure shall perform. The new structure will take advantage of new developments in computational tools, using a nested hierarchy to store data. Here, the structure can be stored in text form (such as an XML file) for human readability and data sharing, or itmore » can be stored in binary to optimize data access. In this paper, we present the progress towards completing the requirements, specifications and implementation of the new structure.« less

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.

Connecticut permanent long-term bridge monitoring network, volume 7 : lessons learned for specifications to guide design of structural health monitoring systems.

DOT National Transportation Integrated Search

2014-08-01

This report proposes a set of specifications for bridge structural health monitoring that has resulted from the : experiences gained during the installation and monitoring of six permanent long-term bridge monitoring systems in : Connecticut. As expe...

Design and fabrication of Rene 41 advanced structural panels. [their performance under axial compression, shear, and bending loads

NASA Technical Reports Server (NTRS)

Greene, B. E.; Northrup, R. F.

1975-01-01

The efficiency was investigated of curved elements in the design of lightweight structural panels under combined loads of axial compression, inplane shear, and bending. The application is described of technology generated in the initial aluminum program to the design and fabrication of Rene 41 panels for subsequent performance tests at elevated temperature. Optimum designs for two panel configurations are presented. The designs are applicable to hypersonic airplane wing structure, and are designed specifically for testing at elevated temperature in the hypersonic wing test structure located at the NASA Flight Research Center. Fabrication methods developed to produce the Rene panels are described, and test results of smaller structural element specimens are presented to verify the design and fabrication methods used. Predicted strengths of the panels under several proposed elevated temperature test load conditions are presented.

Reliability-based evaluation of bridge components for consistent safety margins.

DOT National Transportation Integrated Search

2010-10-01

The Load and Resistant Factor Design (LRFD) approach is based on the concept of structural reliability. The approach is more : rational than the former design approaches such as Load Factor Design or Allowable Stress Design. The LRFD Specification fo...

Crystal structure of the N domain of human somatic angiotensin I-converting enzyme provides a structural basis for domain-specific inhibitor design.

PubMed

Corradi, Hazel R; Schwager, Sylva L U; Nchinda, Aloysius T; Sturrock, Edward D; Acharya, K Ravi

2006-03-31

Human somatic angiotensin I-converting enzyme (sACE) is a key regulator of blood pressure and an important drug target for combating cardiovascular and renal disease. sACE comprises two homologous metallopeptidase domains, N and C, joined by an inter-domain linker. Both domains are capable of cleaving the two hemoregulatory peptides angiotensin I and bradykinin, but differ in their affinities for a range of other substrates and inhibitors. Previously we determined the structure of testis ACE (C domain); here we present the crystal structure of the N domain of sACE (both in the presence and absence of the antihypertensive drug lisinopril) in order to aid the understanding of how these two domains differ in specificity and function. In addition, the structure of most of the inter-domain linker allows us to propose relative domain positions for sACE that may contribute to the domain cooperativity. The structure now provides a platform for the design of "domain-specific" second-generation ACE inhibitors.

Mission-oriented requirements for updating MIL-H-8501. Volume 1: STI proposed structure. [military rotorcraft

NASA Technical Reports Server (NTRS)

Clement, W. F.; Hoh, R. H.; Ferguson, S. W., III; Mitchell, D. G.; Ashkenas, I. L.; Mcruer, D. T.

1985-01-01

The structure of a new flying and ground handling qualities specification for military rotorcraft is presented. This preliminary specification structure is intended to evolve into a replacement for specification MIL-H-8501A. The new structure is designed to accommodate a variety of rotorcraft types, mission flight phases, flight envelopes, and flight environmental characteristics and to provide criteria for three levels of flying qualities, a systematic treatment of failures and reliability, both conventional and multiaxis controllers, and external vision aids which may also incorporate synthetic display content. Existing and new criteria were incorporated into the new structure wherever they could be substantiated.

A structural model for composite rotor blades and lifting surfaces

NASA Technical Reports Server (NTRS)

Rehfield, Lawrence W.; Atilgan, Ali R.

1987-01-01

Composite material systems are currently candidates for aerospace structures, primarily for the design flexibiity they offer i.e., it is possible to tailor the material and manufacturing approach to the application. Two notable examples are the wing of the Grumman/USAF/DARPA X-29 and rotor blades under development by the U.S.A. Aerostructures Directorate (AVSCOM), Langley Research Center. A working definition of elastic or structural tailoring is the use of structural concept, fiber orientation, ply stacking sequence, and a blend of materials to achieve specific performance goals. In the design process, choices of materials and dimensions are made which produce specific response characteristics which permit the selected goals to be achieved. Common choices for tailoring goals are preventing instabilities or vibration resonances or enhancing damage tolerance. An essential, enabling factor in the design of tailored composite structures is structural modeling that accurately, but simply, characterizes response. The objective of this paper is to improve the single-cell beam model for composite rotor blades or lifting surfaces and to demonstrate its usefullness in applications.

Structural design of Kaohsiung Stadium, Taiwan

USGS Publications Warehouse

Watanabe, Hideyuki; Tanno, Yoshiro; Nakai, Masayoshi; Ohshima, Takashi; Suguichi, Akihiro; Lee, William H.; Wang, Jensen

2013-01-01

This paper presents an outline description of the structural design of the main stadium for the World Games held in Kaohsiung City, Taiwan, in 2009. Three new design concepts, unseen in previous stadiums, were proposed and realized: “an open stadium”, “an urban park”, and “a spiral continuous form”. Based on the open stadium concept, simple cantilever trusses in the roof structure were arranged in a delicate rhythm, and a so-called oscillating hoop of steel tubes was wound around the top and bottom surfaces of a group of cantilever trusses to form a continuous spiral form. Also, at the same time by clearly grouping the structural elements of the roof structure, the dramatic effect of the urban park was highlighted by unifying the landscape and the spectator seating area to form the stadium facade. This paper specifically reports on the overview of the building, concepts of structural design, structural analysis of the roof, roof design, foundation design, and an outline of the construction.

Numerical simulation of vehicle crashworthiness and occupant protection

NASA Astrophysics Data System (ADS)

Saha, Nripen K.

1993-08-01

Numerical simulation of vehicle crashworthiness and occupant protection are addressed. The vehicle crashworthiness design objectives are to design the vehicle structure for optimum impact energy absorption, and to design the restraint system (seatbelts, airbags, bolsters, etc.) for optimum occupant protection. The following approaches are taken; a major part of the impact energy is to be absorbed by the vehicle structure; the restraint components will provide protection against the remaining crash energy; certain vehicle components are designed to deform under specific types and speeds of impact in a desired mode for sound energy management; structural components such as front side rails, rear rails, door structure and pillars undergo large amounts of deformation; and with properly designed geometry and material these components assist in mitigating the effects of impact.

Numerical simulation of vehicle crashworthiness and occupant protection

NASA Technical Reports Server (NTRS)

Saha, Nripen K.

1993-01-01

Numerical simulation of vehicle crashworthiness and occupant protection are addressed. The vehicle crashworthiness design objectives are to design the vehicle structure for optimum impact energy absorption, and to design the restraint system (seatbelts, airbags, bolsters, etc.) for optimum occupant protection. The following approaches are taken; a major part of the impact energy is to be absorbed by the vehicle structure; the restraint components will provide protection against the remaining crash energy; certain vehicle components are designed to deform under specific types and speeds of impact in a desired mode for sound energy management; structural components such as front side rails, rear rails, door structure and pillars undergo large amounts of deformation; and with properly designed geometry and material these components assist in mitigating the effects of impact.

Specification and Design Methodologies for High-Speed Fault-Tolerant Array Algorithms and Structures for VLSI.

DTIC Science & Technology

1987-06-01

evaluation and chip layout planning for VLSI digital systems. A high-level applicative (functional) language, implemented at UCLA, allows combining of...operating system. 2.1 Introduction The complexity of VLSI requires the application of CAD tools at all levels of the design process. In order to be...effective, these tools must be adaptive to the specific design. In this project we studied a design method based on the use of applicative languages

Methods for combining payload parameter variations with input environment. [calculating design limit loads compatible with probabilistic structural design criteria

NASA Technical Reports Server (NTRS)

Merchant, D. H.

1976-01-01

Methods are presented for calculating design limit loads compatible with probabilistic structural design criteria. The approach is based on the concept that the desired limit load, defined as the largest load occurring in a mission, is a random variable having a specific probability distribution which may be determined from extreme-value theory. The design limit load, defined as a particular of this random limit load, is the value conventionally used in structural design. Methods are presented for determining the limit load probability distributions from both time-domain and frequency-domain dynamic load simulations. Numerical demonstrations of the method are also presented.

Toward high-resolution computational design of helical membrane protein structure and function

PubMed Central

Barth, Patrick; Senes, Alessandro

2016-01-01

The computational design of α-helical membrane proteins is still in its infancy but has made important progress. De novo design has produced stable, specific and active minimalistic oligomeric systems. Computational re-engineering can improve stability and modulate the function of natural membrane proteins. Currently, the major hurdle for the field is not computational, but the experimental characterization of the designs. The emergence of new structural methods for membrane proteins will accelerate progress PMID:27273630

Toward high-resolution computational design of the structure and function of helical membrane proteins.

PubMed

Barth, Patrick; Senes, Alessandro

2016-06-07

The computational design of α-helical membrane proteins is still in its infancy but has already made great progress. De novo design allows stable, specific and active minimal oligomeric systems to be obtained. Computational reengineering can improve the stability and function of naturally occurring membrane proteins. Currently, the major hurdle for the field is the experimental characterization of the designs. The emergence of new structural methods for membrane proteins will accelerate progress.

Integration of dynamic, aerodynamic, and structural optimization of helicopter rotor blades

NASA Technical Reports Server (NTRS)

Peters, David A.

1991-01-01

Summarized here is the first six years of research into the integration of structural, dynamic, and aerodynamic considerations in the design-optimization process for rotor blades. Specifically discussed here is the application of design optimization techniques for helicopter rotor blades. The reduction of vibratory shears and moments at the blade root, aeroelastic stability of the rotor, optimum airframe design, and an efficient procedure for calculating system sensitivities with respect to the design variables used are discussed.

Rotor systems research aircraft predesign study. Volume 4: Preliminary draft detail specification

NASA Technical Reports Server (NTRS)

Miller, A. N.; Linden, A. W.

1972-01-01

The RSRA requirements are presented in a detail specification format. Coverage of the requirements includes the following headings: (1) aircraft characteristics, (2) general features of design and construction, (3) aerodynamics, (4) structural design criteria, (5) flight control system, (6) propulsion subsystem, and (7) secondary power and distribution subsystem.

Design of microarray experiments for genetical genomics studies.

PubMed

Bueno Filho, Júlio S S; Gilmour, Steven G; Rosa, Guilherme J M

2006-10-01

Microarray experiments have been used recently in genetical genomics studies, as an additional tool to understand the genetic mechanisms governing variation in complex traits, such as for estimating heritabilities of mRNA transcript abundances, for mapping expression quantitative trait loci, and for inferring regulatory networks controlling gene expression. Several articles on the design of microarray experiments discuss situations in which treatment effects are assumed fixed and without any structure. In the case of two-color microarray platforms, several authors have studied reference and circular designs. Here, we discuss the optimal design of microarray experiments whose goals refer to specific genetic questions. Some examples are used to illustrate the choice of a design for comparing fixed, structured treatments, such as genotypic groups. Experiments targeting single genes or chromosomic regions (such as with transgene research) or multiple epistatic loci (such as within a selective phenotyping context) are discussed. In addition, microarray experiments in which treatments refer to families or to subjects (within family structures or complex pedigrees) are presented. In these cases treatments are more appropriately considered to be random effects, with specific covariance structures, in which the genetic goals relate to the estimation of genetic variances and the heritability of transcriptional abundances.

High-frequency output characteristics of AlGaAs/GaAs heterojunction bipolar transistors for large-signal applications

NASA Astrophysics Data System (ADS)

Chen, J.; Gao, G. B.; Ünlü, M. S.; Morkoç, H.

1991-11-01

High-frequency ic- vce output characteristics of bipolar transistors, derived from calculated device cutoff frequencies, are reported. The generation of high-frequency output characteristics from device design specifications represents a novel bridge between microwave circuit design and device design: the microwave performance of simulated device structures can be analyzed, or tailored transistor device structures can be designed to fit specific circuit applications. The details of our compact transistor model are presented, highlighting the high-current base-widening (Kirk) effect. The derivation of the output characteristics from the modeled cutoff frequencies are then presented, and the computed characteristics of an AlGaAs/GaAs heterojunction bipolar transistor operating at 10 GHz are analyzed. Applying the derived output characteristics to microwave circuit design, we examine large-signal class A and class B amplification.

Design of Learning Spaces: Emotional and Cognitive Effects of Learning Environments in Relation to Child Development

ERIC Educational Resources Information Center

Arndt, Petra A.

2012-01-01

The design of learning spaces is rightly gaining more and more pedagogical attention, as they influence the learning climate and learning results in multiple ways. General structural characteristics influence the willingness to learn through emotional well-being and a sense of security. Specific structural characteristics influence cognitive…

Using the [beta][subscript 2]-Adrenoceptor for Structure-Based Drug Design

ERIC Educational Resources Information Center

Manallack, David T.; Chalmers, David K.; Yuriev, Elizabeth

2010-01-01

The topics of molecular modeling and drug design are studied in a medicinal chemistry course. The recently reported structures of several G protein-coupled receptors (GPCR) with bound ligands have been used to develop a simple computer-based experiment employing molecular-modeling software. Knowledge of the specific interactions between a ligand…

A photovoltaic catenary-tent array for the Martian surface

NASA Technical Reports Server (NTRS)

Crutchik, M.; Colozza, Anthony J.; Appelbaum, J.

1993-01-01

To provide electrical power during an exploration mission to Mars, a deployable tent-shaped structure with a flexible photovoltaic (PV) blanket is proposed. The array is designed with a self-deploying mechanism utilizing pressurized gas expansion. The structural design for the array uses a combination of cables, beams, and columns to support and deploy the PV blanket. Under the force of gravity a cable carrying a uniform load will take the shape of a catenary curve. A catenary-tent collector is self shadowing which must be taken into account in the solar radiation calculation. The shape and the area of the shadow on the array was calculated and used in the determination of the global radiation on the array. The PV blanket shape and structure dimension were optimized to achieve a configuration which maximizes the specific power (W/kg). The optimization was performed for four types of PV blankets (Si, GaAs/Ge, GaAs CLEFT, and amorphous Si) and four types of structure materials (Carbon composite, Aramid Fiber composite, Aluminum, and Magnesium). The results show that the catenary shape of the PV blanket, which produces the highest specific power, corresponds to zero end angle at the base with respect to the horizontal. The tent angle is determined by the combined effect of the array structure specific mass and the PV blanket output power. The combination of carbon composite structural material and GaAs CLEFT solar cells produce the highest specific power. The study was carried out for two sites on Mars corresponding to the Viking Lander locations. The designs were also compared for summer, winter, and yearly operation.

RExPrimer: an integrated primer designing tool increases PCR effectiveness by avoiding 3' SNP-in-primer and mis-priming from structural variation

PubMed Central

2009-01-01

Background Polymerase chain reaction (PCR) is very useful in many areas of molecular biology research. It is commonly observed that PCR success is critically dependent on design of an effective primer pair. Current tools for primer design do not adequately address the problem of PCR failure due to mis-priming on target-related sequences and structural variations in the genome. Methods We have developed an integrated graphical web-based application for primer design, called RExPrimer, which was written in Python language. The software uses Primer3 as the primer designing core algorithm. Locally stored sequence information and genomic variant information were hosted on MySQLv5.0 and were incorporated into RExPrimer. Results RExPrimer provides many functionalities for improved PCR primer design. Several databases, namely annotated human SNP databases, insertion/deletion (indel) polymorphisms database, pseudogene database, and structural genomic variation databases were integrated into RExPrimer, enabling an effective without-leaving-the-website validation of the resulting primers. By incorporating these databases, the primers reported by RExPrimer avoid mis-priming to related sequences (e.g. pseudogene, segmental duplication) as well as possible PCR failure because of structural polymorphisms (SNP, indel, and copy number variation (CNV)). To prevent mismatching caused by unexpected SNPs in the designed primers, in particular the 3' end (SNP-in-Primer), several SNP databases covering the broad range of population-specific SNP information are utilized to report SNPs present in the primer sequences. Population-specific SNP information also helps customize primer design for a specific population. Furthermore, RExPrimer offers a graphical user-friendly interface through the use of scalable vector graphic image that intuitively presents resulting primers along with the corresponding gene structure. In this study, we demonstrated the program effectiveness in successfully generating primers for strong homologous sequences. Conclusion The improvements for primer design incorporated into RExPrimer were demonstrated to be effective in designing primers for challenging PCR experiments. Integration of SNP and structural variation databases allows for robust primer design for a variety of PCR applications, irrespective of the sequence complexity in the region of interest. This software is freely available at http://www4a.biotec.or.th/rexprimer. PMID:19958502

Development of an integrated CAD-FEA system for patient-specific design of spinal cages.

PubMed

Zhang, Mingzheng; Pu, Fang; Xu, Liqiang; Zhang, Linlin; Liang, Hang; Li, Deyu; Wang, Yu; Fan, Yubo

2017-03-01

Spinal cages are used to create a suitable mechanical environment for interbody fusion in cases of degenerative spinal instability. Due to individual variations in bone structures and pathological conditions, patient-specific cages can provide optimal biomechanical conditions for fusion, strengthening patient recovery. Finite element analysis (FEA) is a valuable tool in the biomechanical evaluation of patient-specific cage designs, but the time- and labor-intensive process of modeling limits its clinical application. In an effort to facilitate the design and analysis of patient-specific spinal cages, an integrated CAD-FEA system (CASCaDeS, comprehensive analytical spinal cage design system) was developed. This system produces a biomechanical-based patient-specific design of spinal cages and is capable of rapid implementation of finite element modeling. By comparison with commercial software, this system was validated and proven to be both accurate and efficient. CASCaDeS can be used to design patient-specific cages with a superior biomechanical performance to commercial spinal cages.

Characterization of radiation effects in 65 nm digital circuits with the DRAD digital radiation test chip

NASA Astrophysics Data System (ADS)

Jara Casas, L. M.; Ceresa, D.; Kulis, S.; Miryala, S.; Christiansen, J.; Francisco, R.; Gnani, D.

2017-02-01

A Digital RADiation (DRAD) test chip has been specifically designed to study the impact of Total Ionizing Dose (TID) (<1 Grad) and Single Event Upset (SEU) on digital logic gates in a 65 nm CMOS technology. Nine different versions of standard cell libraries are studied in this chip, basically differing in the device dimensions, Vt flavor and layout of the device. Each library has eighteen test structures specifically designed to characterize delay degradation and power consumption of the standard cells. For SEU study, a dedicated test structure based on a shift register is designed for each library. TID results up to 500 Mrad are reported.

Automated Verification of Design Patterns with LePUS3

NASA Technical Reports Server (NTRS)

Nicholson, Jonathan; Gasparis, Epameinondas; Eden, Ammon H.; Kazman, Rick

2009-01-01

Specification and [visual] modelling languages are expected to combine strong abstraction mechanisms with rigour, scalability, and parsimony. LePUS3 is a visual, object-oriented design description language axiomatized in a decidable subset of the first-order predicate logic. We demonstrate how LePUS3 is used to formally specify a structural design pattern and prove ( verify ) whether any JavaTM 1.4 program satisfies that specification. We also show how LePUS3 specifications (charts) are composed and how they are verified fully automatically in the Two-Tier Programming Toolkit.

Designing patient-specific 3D printed craniofacial implants using a novel topology optimization method.

PubMed

Sutradhar, Alok; Park, Jaejong; Carrau, Diana; Nguyen, Tam H; Miller, Michael J; Paulino, Glaucio H

2016-07-01

Large craniofacial defects require efficient bone replacements which should not only provide good aesthetics but also possess stable structural function. The proposed work uses a novel multiresolution topology optimization method to achieve the task. Using a compliance minimization objective, patient-specific bone replacement shapes can be designed for different clinical cases that ensure revival of efficient load transfer mechanisms in the mid-face. In this work, four clinical cases are introduced and their respective patient-specific designs are obtained using the proposed method. The optimized designs are then virtually inserted into the defect to visually inspect the viability of the design . Further, once the design is verified by the reconstructive surgeon, prototypes are fabricated using a 3D printer for validation. The robustness of the designs are mechanically tested by subjecting them to a physiological loading condition which mimics the masticatory activity. The full-field strain result through 3D image correlation and the finite element analysis implies that the solution can survive the maximum mastication of 120 lb. Also, the designs have the potential to restore the buttress system and provide the structural integrity. Using the topology optimization framework in designing the bone replacement shapes would deliver surgeons new alternatives for rather complicated mid-face reconstruction.

Earth Observatory Satellite system definition study. Report 5: System design and specifications. Volume 3: General purpose spacecraft segment and module specifications

NASA Technical Reports Server (NTRS)

1974-01-01

The specifications for the Earth Observatory Satellite (EOS) general purpose aircraft segment are presented. The satellite is designed to provide attitude stabilization, electrical power, and a communications data handling subsystem which can support various mission peculiar subsystems. The various specifications considered include the following: (1) structures subsystem, (2) thermal control subsystem, (3) communications and data handling subsystem module, (4) attitude control subsystem module, (5) power subsystem module, and (6) electrical integration subsystem.

General specifications for the development of a PC-based simulator of the NASA RECON system

NASA Technical Reports Server (NTRS)

Dominick, Wayne D. (Editor); Triantafyllopoulos, Spiros

1984-01-01

The general specifications for the design and implementation of an IBM PC/XT-based simulator of the NASA RECON system, including record designs, file structure designs, command language analysis, program design issues, error recovery considerations, and usage monitoring facilities are discussed. Once implemented, such a simulator will be utilized to evaluate the effectiveness of simulated information system access in addition to actual system usage as part of the total educational programs being developed within the NASA contract.

Structural analysis considerations for wind turbine blades

NASA Technical Reports Server (NTRS)

Spera, D. A.

1979-01-01

Approaches to the structural analysis of wind turbine blade designs are reviewed. Specifications and materials data are discussed along with the analysis of vibrations, loads, stresses, and failure modes.

Structural dynamics technology research in NASA: Perspective on future needs

NASA Technical Reports Server (NTRS)

1979-01-01

The perspective of a NASA ad hoc study group on future research needs in structural dynamics within the aerospace industry is presented. The common aspects of the design process across the industry are identified and the role of structural dynamics is established through a discussion of various design considerations having their basis in structural dynamics. The specific structural dynamics issues involved are identified and assessed as to their current technological status and trends. Projections of future requirements based on this assessment are made and areas of research to meet them are identified.

Design and optimization of a self-deploying PV tent array

NASA Astrophysics Data System (ADS)

Colozza, Anthony J.

A study was performed to design a self-deploying tent shaped PV (photovoltaic) array and optimize the design for maximum specific power. Each structural component of the design was analyzed to determine the size necessary to withstand the various forces it would be subjected to. Through this analysis the component weights were determined. An optimization was performed to determine the array dimensions and blanket geometry which produce the maximum specific power for a given PV blanket. This optimization was performed for both Lunar and Martian environmental conditions. The performance specifications for the array at both locations and with various PV blankets were determined.

Students' Representations of the Atomic Structure--The Effect of Some Individual Differences in Particular Task Contexts

ERIC Educational Resources Information Center

Papageorgiou, George; Markos, Angelos; Zarkadis, Nikolaos

2016-01-01

The current study aims to investigate students' representations of the atomic structure in a number of student cohorts with specific characteristics concerning age, grade, class curriculum and some individual differences, such as formal reasoning and field dependence/independence. Two specific task contexts, which were designed in accordance with…

Taking Action--Mathematics Curricular Organization for Effective Teaching and Learning

ERIC Educational Resources Information Center

Appelbaum, Peter

2009-01-01

The curricular structure of Taking Action is described and analyzed as a form of culturally responsive and culturally specific pedagogy. In this design structure, students reconsider what they have done and identify key aspects of their experience. Based on this reflection, they design a way to interact with people outside of their class in order…

Molecular Structure of Photosynthetic Microbial Biofuels for Improved Engine Combustion and Emissions Characteristics

PubMed Central

Hellier, Paul; Purton, Saul; Ladommatos, Nicos

2015-01-01

The metabolic engineering of photosynthetic microbes for production of novel hydrocarbons presents an opportunity for development of advanced designer biofuels. These can be significantly more sustainable, throughout the production-to-consumption lifecycle, than the fossil fuels and crop-based biofuels they might replace. Current biofuels, such as bioethanol and fatty acid methyl esters, have been developed primarily as drop-in replacements for existing fossil fuels, based on their physical properties and autoignition characteristics under specific combustion regimes. However, advances in the genetic engineering of microalgae and cyanobacteria, and the application of synthetic biology approaches offer the potential of designer strains capable of producing hydrocarbons and oxygenates with specific molecular structures. Furthermore, these fuel molecules can be designed for higher efficiency of energy release and lower exhaust emissions during combustion. This paper presents a review of potential fuel molecules from photosynthetic microbes and the performance of these possible fuels in modern internal combustion engines, highlighting which modifications to the molecular structure of such fuels may enhance their suitability for specific combustion regimes. PMID:25941673

Molecular structure of photosynthetic microbial biofuels for improved engine combustion and emissions characteristics.

PubMed

Hellier, Paul; Purton, Saul; Ladommatos, Nicos

2015-01-01

The metabolic engineering of photosynthetic microbes for production of novel hydrocarbons presents an opportunity for development of advanced designer biofuels. These can be significantly more sustainable, throughout the production-to-consumption lifecycle, than the fossil fuels and crop-based biofuels they might replace. Current biofuels, such as bioethanol and fatty acid methyl esters, have been developed primarily as drop-in replacements for existing fossil fuels, based on their physical properties and autoignition characteristics under specific combustion regimes. However, advances in the genetic engineering of microalgae and cyanobacteria, and the application of synthetic biology approaches offer the potential of designer strains capable of producing hydrocarbons and oxygenates with specific molecular structures. Furthermore, these fuel molecules can be designed for higher efficiency of energy release and lower exhaust emissions during combustion. This paper presents a review of potential fuel molecules from photosynthetic microbes and the performance of these possible fuels in modern internal combustion engines, highlighting which modifications to the molecular structure of such fuels may enhance their suitability for specific combustion regimes.

Shape optimization of disc-type flywheels

NASA Technical Reports Server (NTRS)

Nizza, R. S.

1976-01-01

Techniques were developed for presenting an analytical and graphical means for selecting an optimum flywheel system design, based on system requirements, geometric constraints, and weight limitations. The techniques for creating an analytical solution are formulated from energy and structural principals. The resulting flywheel design relates stress and strain pattern distribution, operating speeds, geometry, and specific energy levels. The design techniques incorporate the lowest stressed flywheel for any particular application and achieve the highest specific energy per unit flywheel weight possible. Stress and strain contour mapping and sectional profile plotting reflect the results of the structural behavior manifested under rotating conditions. This approach toward flywheel design is applicable to any metal flywheel, and permits the selection of the flywheel design to be based solely on the criteria of the system requirements that must be met, those that must be optimized, and those system parameters that may be permitted to vary.

Secondary structure prediction and structure-specific sequence analysis of single-stranded DNA.

PubMed

Dong, F; Allawi, H T; Anderson, T; Neri, B P; Lyamichev, V I

2001-08-01

DNA sequence analysis by oligonucleotide binding is often affected by interference with the secondary structure of the target DNA. Here we describe an approach that improves DNA secondary structure prediction by combining enzymatic probing of DNA by structure-specific 5'-nucleases with an energy minimization algorithm that utilizes the 5'-nuclease cleavage sites as constraints. The method can identify structural differences between two DNA molecules caused by minor sequence variations such as a single nucleotide mutation. It also demonstrates the existence of long-range interactions between DNA regions separated by >300 nt and the formation of multiple alternative structures by a 244 nt DNA molecule. The differences in the secondary structure of DNA molecules revealed by 5'-nuclease probing were used to design structure-specific probes for mutation discrimination that target the regions of structural, rather than sequence, differences. We also demonstrate the performance of structure-specific 'bridge' probes complementary to non-contiguous regions of the target molecule. The structure-specific probes do not require the high stringency binding conditions necessary for methods based on mismatch formation and permit mutation detection at temperatures from 4 to 37 degrees C. Structure-specific sequence analysis is applied for mutation detection in the Mycobacterium tuberculosis katG gene and for genotyping of the hepatitis C virus.

antaRNA: ant colony-based RNA sequence design.

PubMed

Kleinkauf, Robert; Mann, Martin; Backofen, Rolf

2015-10-01

RNA sequence design is studied at least as long as the classical folding problem. Although for the latter the functional fold of an RNA molecule is to be found ,: inverse folding tries to identify RNA sequences that fold into a function-specific target structure. In combination with RNA-based biotechnology and synthetic biology ,: reliable RNA sequence design becomes a crucial step to generate novel biochemical components. In this article ,: the computational tool antaRNA is presented. It is capable of compiling RNA sequences for a given structure that comply in addition with an adjustable full range objective GC-content distribution ,: specific sequence constraints and additional fuzzy structure constraints. antaRNA applies ant colony optimization meta-heuristics and its superior performance is shown on a biological datasets. http://www.bioinf.uni-freiburg.de/Software/antaRNA CONTACT: backofen@informatik.uni-freiburg.de Supplementary data are available at Bioinformatics online. © The Author 2015. Published by Oxford University Press.

Hierarchically structured activated carbon for ultracapacitors

NASA Astrophysics Data System (ADS)

Kim, Mok-Hwa; Kim, Kwang-Bum; Park, Sun-Min; Roh, Kwang Chul

2016-02-01

To resolve the pore-associated bottleneck problem observed in the electrode materials used for ultracapacitors, which inhibits the transport of the electrolyte ions, we designed hierarchically structured activated carbon (HAC) by synthesizing a mesoporous silica template/carbon composite and chemically activating it to simultaneously remove the silica template and increase the pore volume. The resulting HAC had a well-designed, unique porous structure, which allowed for large interfaces for efficient electric double-layer formation. Given the unique characteristics of the HAC, we believe that the developed synthesis strategy provides important insights into the design and fabrication of hierarchical carbon nanostructures. The HAC, which had a specific surface area of 1,957 m2 g-1, exhibited an extremely high specific capacitance of 157 F g-1 (95 F cc-1), as well as a high rate capability. This indicated that it had superior energy storage capability and was thus suitable for use in advanced ultracapacitors.

Telecom Link--A Competitive Simulated Design Exercise.

ERIC Educational Resources Information Center

Freeman, J.; Allen, J.

1982-01-01

Telecom link is a structured design exercise concerned with building a telecommunications link between London and Amsterdam. Designed for A-level physics, the simulation requires a minimum of 10 hours. Aims of the exercise, design specifications and technical aspects, and summaries of four possible technologies used in the simulation are…

Computerized Adaptive Testing System Design: Preliminary Design Considerations.

ERIC Educational Resources Information Center

Croll, Paul R.

A functional design model for a computerized adaptive testing (CAT) system was developed and presented through a series of hierarchy plus input-process-output (HIPO) diagrams. System functions were translated into system structure: specifically, into 34 software components. Implementation of the design in a physical system was addressed through…

Flexibility in flood management design: proactive planning under uncertainty

NASA Astrophysics Data System (ADS)

Smet, K.; de Neufville, R.; van der Vlist, M.

2016-12-01

This paper presents a value-enhancing approach for proactive planning and design of long-lived flood management infrastructure given uncertain future flooding threats. Designing infrastructure that can be adapted over time is a method to safeguard the efficacy of current design decisions given future uncertainties. We explore the value of embedding "options" in a physical structure, where an option is the right but not the obligation to do something at a later date (e.g. over-dimensioning a floodwall foundation now facilitates a future height addition in response to observed increases in sea level; building extra pump bays in a drainage pumping station enables the easy addition of pumping capacity whenever increased precipitation warrants an expansion.) The proposed approach couples a simulation model that captures future climate induced changes to the hydrologic operating environment of a structure, with an economic model that estimates the lifetime economic performance of alternative investment strategies. The economic model uses Real "In" Options analysis, a type of cash flow analysis that quantifies the implicit value of options and the flexibility they provide. We demonstrate the approach using replacement planning for the multi-functional pumping station IJmuiden on the North Sea Canal in the Netherlands. The analysis models flexibility in design decisions, varying the size and specific options included in the new structure. Results indicate that the incorporation of options within the structural design has the potential to improve its economic performance, as compared to more traditional, "build it once and build it big" designs where flexibility is not an explicit design criterion. The added value resulting from the incorporation of flexibility varies with the range of future conditions considered, and the specific options examined. This approach could be applied to explore investment strategies for the design of other flood management structures, as well as be expanded to look more at flexibility within an infrastructure network rather than a single structure. Flexibility in flood management design:proactive planning under uncertainty

Using Symmetry to Design Self-Assembling Protein Cages and Nanomaterials on the Mid-Nanometer Scale

NASA Astrophysics Data System (ADS)

Yeates, Todd

Self-assembling molecular structures having diverse cellular functions are widespread in nature. Some of the largest and most sophisticated types are built from many copies of the same or similar protein molecules arranged following principles of symmetry. A long-standing engineering goal has been to design novel protein molecules to self-assemble into geometrically specific structures similar to the extraordinary structures that have evolved in Nature. Practical routes to this goal have been developed by using ideas in symmetry to articulate the minimum design requirements for achieving various types of symmetric architectures, including cages, extended two-dimensional layers, and three-dimensional crystalline materials. The key requirement is that two distinct self-associating interfaces, each conferring one element of rotational symmetry, have to be engineered into the protein molecule (or molecules), following particular geometric specifications. The main principle is that combining two separate symmetry elements into a single molecular entity produces a molecule that necessarily assembles into an architecture dictated by a symmetry group that is the product of the two simpler contributing symmetries. Recent experiments have demonstrated success using a variety of symmetry-based strategies. Strategic variations are emerging that differ from each other with respect to biophysical features such as flexibility vs rigidity in the assembled structures, and with respect to design aspects such as whether the protein interfaces are inherited from natural oligomeric proteins or are designed de novo by advanced computational methods. The success of these strategies has been proven by determining crystal structures of several giant, self-assembling protein cages and clusters (10-25 nm in diameter), created by design. The ability to create sophisticated supramolecular structures from designed protein subunits opens the way to broad applications in synthetic biology and nanotechnology.

Hafnium transistor process design for neural interfacing.

PubMed

Parent, David W; Basham, Eric J

2009-01-01

A design methodology is presented that uses 1-D process simulations of Metal Insulator Semiconductor (MIS) structures to design the threshold voltage of hafnium oxide based transistors used for neural recording. The methodology is comprised of 1-D analytical equations for threshold voltage specification, and doping profiles, and 1-D MIS Technical Computer Aided Design (TCAD) to design a process to implement a specific threshold voltage, which minimized simulation time. The process was then verified with a 2-D process/electrical TCAD simulation. Hafnium oxide films (HfO) were grown and characterized for dielectric constant and fixed oxide charge for various annealing temperatures, two important design variables in threshold voltage design.

DNA-binding specificity prediction with FoldX.

PubMed

Nadra, Alejandro D; Serrano, Luis; Alibés, Andreu

2011-01-01

With the advent of Synthetic Biology, a field between basic science and applied engineering, new computational tools are needed to help scientists reach their goal, their design, optimizing resources. In this chapter, we present a simple and powerful method to either know the DNA specificity of a wild-type protein or design new specificities by using the protein design algorithm FoldX. The only basic requirement is having a good resolution structure of the complex. Protein-DNA interaction design may aid the development of new parts designed to be orthogonal, decoupled, and precise in its target. Further, it could help to fine-tune the systems in terms of specificity, discrimination, and binding constants. In the age of newly developed devices and invented systems, computer-aided engineering promises to be an invaluable tool. Copyright © 2011 Elsevier Inc. All rights reserved.

Program for establishing long-time flight service performance of composite materials in the center wing structure of C-130 aircraft. Phase 4: Ground/flight acceptance tests

NASA Technical Reports Server (NTRS)

Harvill, W. E.; Kizer, J. A.

1976-01-01

The advantageous structural uses of advanced filamentary composites are demonstrated by design, fabrication, and test of three boron-epoxy reinforced C-130 center wing boxes. The advanced development work necessary to support detailed design of a composite reinforced C-130 center wing box was conducted. Activities included the development of a basis for structural design, selection and verification of materials and processes, manufacturing and tooling development, and fabrication and test of full-scale portions of the center wing box. Detailed design drawings, and necessary analytical structural substantiation including static strength, fatigue endurance, flutter, and weight analyses are considered. Some additional component testing was conducted to verify the design for panel buckling, and to evaluate specific local design areas. Development of the cool tool restraint concept was completed, and bonding capabilities were evaluated using full-length skin panel and stringer specimens.

Control system design for flexible structures using data models

NASA Technical Reports Server (NTRS)

Irwin, R. Dennis; Frazier, W. Garth; Mitchell, Jerrel R.; Medina, Enrique A.; Bukley, Angelia P.

1993-01-01

The dynamics and control of flexible aerospace structures exercises many of the engineering disciplines. In recent years there has been considerable research in the developing and tailoring of control system design techniques for these structures. This problem involves designing a control system for a multi-input, multi-output (MIMO) system that satisfies various performance criteria, such as vibration suppression, disturbance and noise rejection, attitude control and slewing control. Considerable progress has been made and demonstrated in control system design techniques for these structures. The key to designing control systems for these structures that meet stringent performance requirements is an accurate model. It has become apparent that theoretically and finite-element generated models do not provide the needed accuracy; almost all successful demonstrations of control system design techniques have involved using test results for fine-tuning a model or for extracting a model using system ID techniques. This paper describes past and ongoing efforts at Ohio University and NASA MSFC to design controllers using 'data models.' The basic philosophy of this approach is to start with a stabilizing controller and frequency response data that describes the plant; then, iteratively vary the free parameters of the controller so that performance measures become closer to satisfying design specifications. The frequency response data can be either experimentally derived or analytically derived. One 'design-with-data' algorithm presented in this paper is called the Compensator Improvement Program (CIP). The current CIP designs controllers for MIMO systems so that classical gain, phase, and attenuation margins are achieved. The center-piece of the CIP algorithm is the constraint improvement technique which is used to calculate a parameter change vector that guarantees an improvement in all unsatisfied, feasible performance metrics from iteration to iteration. The paper also presents a recently demonstrated CIP-type algorithm, called the Model and Data Oriented Computer-Aided Design System (MADCADS), developed for achieving H(sub infinity) type design specifications using data models. Control system design for the NASA/MSFC Single Structure Control Facility are demonstrated for both CIP and MADCADS. Advantages of design-with-data algorithms over techniques that require analytical plant models are also presented.

System design and specifications. Earth Observatory Satellite system definition study (EOS)

NASA Technical Reports Server (NTRS)

1974-01-01

A design summary of the Earth Observatory Satellite (EOS) is presented. The systems considered in the summary are: (1) the spacecraft structure, (2) electrical power modules, (3) communications and data handling module, (4) attitude determination module, (5) actuation module, and (6) solar array and drive module. The documents which provide the specifications for the systems and the equipment are identified.

Structure and Computation in Immunoreagent Design: From Diagnostics to Vaccines.

PubMed

Gourlay, Louise; Peri, Claudio; Bolognesi, Martino; Colombo, Giorgio

2017-12-01

Novel immunological tools for efficient diagnosis and treatment of emerging infections are urgently required. Advances in the diagnostic and vaccine development fields are continuously progressing, with reverse vaccinology and structural vaccinology (SV) methods for antigen identification and structure-based antigen (re)design playing increasingly relevant roles. SV, in particular, is predicted to be the front-runner in the future development of diagnostics and vaccines targeting challenging diseases such as AIDS and cancer. We review state-of-the-art methodologies for structure-based epitope identification and antigen design, with specific applicative examples. We highlight the implications of such methods for the engineering of biomolecules with improved immunological properties, potential diagnostic and/or therapeutic uses, and discuss the perspectives of structure-based rational design for the production of advanced immunoreagents. Copyright © 2017 Elsevier Ltd. All rights reserved.

Dynamic/Jitter Assessment of Multiple Potential HabEx Structural Designs

NASA Technical Reports Server (NTRS)

Knight, J. Brent; Stahl, H. Philip; Singleton, Andy; Hunt, Ron; Therrell, Melissa; Caldwell, Kate; Garcia, Jay; Baysinger, Mike

2017-01-01

One of the driving structural requirements of the Habitable Exo-Planet (HabEx) telescope is to maintain Line Of Sight (LOS) stability between the Primary Mirror (PM) and Secondary Mirror (SM) of = 5 mas. Dynamic analyses of two configurations of a proposed (HabEx) 4 meter off-axis telescope structure were performed to predict effects of jitter on primary/secondary mirror alignment. The dynamic disturbance used as the forcing function was the James Webb Space Telescope reaction wheel assembly vibration emission specification level. The objective of these analyses was to predict "order-of-magnitude" performance for various structural configurations which will roll into efforts to define the HabEx structural design's global architecture. Two variations of the basic architectural design were analyzed. Relative motion between the PM and the SM for each design configuration are reported.

Dynamic/jitter assessment of multiple potential HabEx structural designs

NASA Astrophysics Data System (ADS)

Knight, J. Brent; Stahl, H. Philip; Singleton, Andy; Hunt, Ron; Therrell, Melissa; Caldwell, Kate; Garcia, Jay; Baysinger, Mike

2017-09-01

One of the driving structural requirements of the Habitable Exo-Planet (HabEx) telescope is to maintain Line Of Sight (LOS) stability between the Primary Mirror (PM) and Secondary Mirror (SM) of <= 5 milli-arc seconds (mas). Dynamic analyses of two configurations of a proposed HabEx 4 meter off-axis telescope structure were performed to predict effects of a vibration input on primary/secondary mirror alignment. The dynamic disturbance used as the forcing function was the James Webb Space Telescope reaction wheel assembly vibration emission specification level. The objective of these analyses was to predict "order-of-magnitude" performance for various structural configurations which contribute to efforts in defining the HabEx structural design's global architecture. Two variations of the basic architectural design were analyzed. Relative motion between the PM and the SM for each design configuration are reported.

Research and Development of Rapid Design Systems for Aerospace Structure

NASA Technical Reports Server (NTRS)

Schaeffer, Harry G.

1999-01-01

This report describes the results of research activities associated with the development of rapid design systems for aerospace structures in support of the Intelligent Synthesis Environment (ISE). The specific subsystems investigated were the interface between model assembly and analysis; and, the high performance NASA GPS equation solver software system in the Windows NT environment on low cost high-performance PCs.

An example problem illustrating the application of the national lime association mixture design and testing protocol (MDTP) to ascertain engineering properties of lime-treated subgrades for mechanistic pavement design/analysis.

DOT National Transportation Integrated Search

2001-09-01

This document presents an example of mechanistic design and analysis using a mix design and : testing protocol. More specifically, it addresses the structural properties of lime-treated subgrade, : subbase, and base layers through mechanistic design ...

Improving the Dynamic Characteristics of Body-in-White Structure Using Structural Optimization

PubMed Central

Yahaya Rashid, Aizzat S.; Mohamed Haris, Sallehuddin; Alias, Anuar

2014-01-01

The dynamic behavior of a body-in-white (BIW) structure has significant influence on the noise, vibration, and harshness (NVH) and crashworthiness of a car. Therefore, by improving the dynamic characteristics of BIW, problems and failures associated with resonance and fatigue can be prevented. The design objectives attempt to improve the existing torsion and bending modes by using structural optimization subjected to dynamic load without compromising other factors such as mass and stiffness of the structure. The natural frequency of the design was modified by identifying and reinforcing the structure at critical locations. These crucial points are first identified by topology optimization using mass and natural frequencies as the design variables. The individual components obtained from the analysis go through a size optimization step to find their target thickness of the structure. The thickness of affected regions of the components will be modified according to the analysis. The results of both optimization steps suggest several design modifications to achieve the target vibration specifications without compromising the stiffness of the structure. A method of combining both optimization approaches is proposed to improve the design modification process. PMID:25101312

Experimental demonstration of the control of flexible structures

NASA Technical Reports Server (NTRS)

Schaechter, D. B.; Eldred, D. B.

1984-01-01

The Large Space Structure Technology Flexible Beam Experiment employs a pinned-free flexible beam to demonstrate such required methods as dynamic and adaptive control, as well as various control law design approaches and hardware requirements. An attempt is made to define the mechanization difficulties that may inhere in flexible structures. Attention is presently given to analytical work performed in support of the test facility's development, the final design's specifications, the control laws' synthesis, and experimental results obtained.

38 CFR 1.15 - Standards for program evaluation.

Code of Federal Regulations, 2011 CFR

2011-07-01

... the data. (f) Each program evaluation requires a systematic research design to collect the data necessary to measure the objectives. This research design should conform to the following: (1) Rationale. The research design for each evaluation should contain a specific rationale and should be structured...

Los Angeles-Gateway Freight Advanced Traveler Information System : final system design and architecture for FRATIS prototype.

DOT National Transportation Integrated Search

2013-05-01

This Final Architecture and Design report has been prepared to describe the structure and design of all the system components for the LA-Gateway FRATIS Demonstration Project. More specifically, this document provides: Detailed descriptions of the...

A static analysis method for barge-impact design of bridges with consideration of dynamic amplification : final report, November 2009.

DOT National Transportation Integrated Search

2009-11-01

Current practice with regard to designing bridge structures to resist impact loads associated with barge collisions relies upon the : use of the American Association of State Highway and Transportation Officials (AASHTO) bridge design specifications....

Mod-5A wind turbine generator program design report. Volume 4: Drawings and specifications, book 1

NASA Astrophysics Data System (ADS)

1984-08-01

The design, development and analysis of the 7.3 MW MOD-5A wind turbine generator is documented. Volume 4 contains the drawings and specifications that were developed in preparation for building the MOD-5A wind turbine generator. This is the first of five books of volume four. It contains structural design criteria, generator step-up transformer specs, specs for design, fabrication and testing of the system, specs for the ground control enclosure, systems specs, slip ring specs, and control system specs.

Mod-5A Wind Turbine Generator Program Design Report. Volume 4: Drawings and Specifications, Book 1

NASA Technical Reports Server (NTRS)

1984-01-01

The design, development and analysis of the 7.3 MW MOD-5A wind turbine generator is documented. Volume 4 contains the drawings and specifications that were developed in preparation for building the MOD-5A wind turbine generator. This is the first of five books of volume four. It contains structural design criteria, generator step-up transformer specs, specs for design, fabrication and testing of the system, specs for the ground control enclosure, systems specs, slip ring specs, and control system specs.

An optimal structure for a 34-meter millimeter-wave center-fed BWG antenna: The Cross-Box concept

NASA Technical Reports Server (NTRS)

Chuang, K. L.

1988-01-01

An approach to the design of the planned NASA/JPL 34 m elevation-over-azimuth (Az-El) antenna structure at the Venus site (DSS-13) is presented. The antenna structural configuration accommodates a large (2.44 m) beam waveguide (BWG) tube centrally routed through the reflector-alidade structure, an elevation wheel design, and an optimal structural geometry. The design encompasses a cross-box elevation wheel-reflector base substructure that preserves homology while satisfying many constraints, such as structure weight, surface tolerance, stresses, natural frequency, and various functional constraints. The functional requirements are set to ensure that microwave performance at millimeter wavelengths is adequate. The cross-box configuration was modeled, optimized, and found to satisfy all DSN HEF baseline antenna specifications. In addition, the structure design was conceptualized and analyzed with an emphasis on preserving the structure envelope and keeping modifications relative to the HEF antennas to a minimum, thus enabling the transferability of the BWG technology for future retrofitting. Good performance results were obtained.

Civionics specifications for fiber optic sensors for structural health monitoring

NASA Astrophysics Data System (ADS)

Rivera, Evangeline; Mufti, Aftab A.; Thomson, Douglas J.

2004-07-01

As the design and construction of civil structures continue to evolve, it is becoming imperative that these structures be monitored for their health. In order to meet this need, the discipline of Civionics has emerged. It involves the applications to civil structures and aims to assist engineers in realizing the full benefits of structural health monitoring (SHM). Therefore, the goal of the specification outlined in this work is to ensure that correct installation and operating of fiber optic sensors, such as bridges, will be discussed that motivated the writing of these specifications. The main reason for the failure of FOS based monitoring systems can be traced directly to the installation of the fiber sensor itself. Therefore, by creating a standard procedure for SHM, several ambiguities are eliminated such as fiber sensor specifications and the types of cables required. As a result, these specifications will help ensure that the sensors will survive the installation process and eventually prove their value over years of monitoring the health of the structure. The Civionics FOS specifications include the requirements for fiber sensors, specifically Bragg grating sensors, and their corresponding readout unit. It also includes specifications on the cables, conduits, junction boxes, cable termination and the environmental.

Capillary Structures for Exploration Life Support (Capillary Structures)

NASA Image and Video Library

2017-07-10

iss052e013081 (7/10/2017) --- The Capillary Structures for Exploration Life Support (Capillary Structures) investigation studies a new method using structures of specific shapes to manage fluid and gas mixtures. The investigation studies water recycling and carbon dioxide removal, benefiting future efforts to design lightweight, more reliable life support systems for future space missions.

The Need for, and the Role of the Toxicological Chemist in the Design of Safer Chemicals.

PubMed

DeVito, Stephen C

2018-02-01

During the past several decades, there has been an ever increasing emphasis for designers of new commercial (nonpharmaceutical) chemicals to include considerations of the potential impacts a planned chemical may have on human health and the environment as part of the design of the chemical, and to design chemicals such that they possess the desired use efficacy while minimizing threats to human health and the environment. Achievement of this goal would be facilitated by the availability of individuals specifically and formally trained to design such chemicals. Medicinal chemists are specifically trained to design and develop safe and clinically efficacious pharmaceutical substances. No such formally trained science hybrid exists for the design of safer commercial (nonpharmaceutical) chemicals. This article describes the need for and role of the "toxicological chemist," an individual who is formally trained in synthetic organic chemistry, biochemistry, physiology, toxicology, environmental science, and in the relationships between structure and commercial use efficacy, structure and toxicity, structure and environmental fate and effects, and global hazard, and trained to integrate this knowledge to design safer commercially efficacious chemicals. Using examples, this article illustrates the role of the toxicological chemist in designing commercially efficacious, safer chemical candidates. Published by Oxford University Press on behalf of the Society of Toxicology 2017. This work is written by a US Government employee and is in the public domain in the US.

Program design by a multidisciplinary team. [for structural finite element analysis on STAR-100 computer

NASA Technical Reports Server (NTRS)

Voigt, S.

1975-01-01

The use of software engineering aids in the design of a structural finite-element analysis computer program for the STAR-100 computer is described. Nested functional diagrams to aid in communication among design team members were used, and a standardized specification format to describe modules designed by various members was adopted. This is a report of current work in which use of the functional diagrams provided continuity and helped resolve some of the problems arising in this long-running part-time project.

76 FR 67419 - Takes of Marine Mammals Incidental to Specified Activities; Piling and Structure Removal in...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-11-01

... unclear how expanded monitoring, in the absence of specific experimental design, would empirically verify..., designed to minimize disturbance to harbor seals within the action area in consideration of timing... February (i.e., within the designated in-water work window designed to reduce impacts to fish species in...

Interdisciplinary and multilevel optimum design. [in aerospace structural engineering

NASA Technical Reports Server (NTRS)

Sobieszczanski-Sobieski, Jaroslaw; Haftka, Raphael T.

1987-01-01

Interactions among engineering disciplines and subsystems in engineering system design are surveyed and specific instances of such interactions are described. Examination of the interactions that a traditional design process in which the numerical values of major design variables are decided consecutively is likely to lead to a suboptimal design. Supporting numerical examples are a glider and a space antenna. Under an alternative approach introduced, the design and its sensitivity data from the subsystems and disciplines are generated concurrently and then made available to the system designer enabling him to modify the system design so as to improve its performance. Examples of a framework structure and an airliner wing illustrate that approach.

Design of overhead VMS structures for fatigue loads.

DOT National Transportation Integrated Search

2011-07-31

The 2001 edition of the American Association of State Highway and Transportation Officials (AASHTO) : Standard Specifications for Structural Supports for Highway Signs, Luminaires and Traffic Signals has been : revised in its entirety through a major...

CSTutor: A Sketch-Based Tool for Visualizing Data Structures

ERIC Educational Resources Information Center

Buchanan, Sarah; Laviola, Joseph J., Jr.

2014-01-01

We present CSTutor, a sketch-based interface designed to help students understand data structures, specifically Linked Lists, Binary Search Trees, AVL Trees, and Heaps. CSTutor creates an environment that seamlessly combines a user's sketched diagram and code. In each of these data structure modes, the user can naturally sketch a data structure on…

Structural (Performance) class Potential for North America

Treesearch

Eric Jones; David E. Kretschmann; Kevin Cheung

2014-01-01

Structural class systems are species-independent product classification systems for structural timber. They are used throughout the world to reduce the number of species and grade choices that face the designer of wood construction projects. Structural class systems offer an opportunity to simplify timber specification in North America and to encourage more effective...

Content Structure in Science Instructional Materials and Knowledge Structure in Students' Memories.

ERIC Educational Resources Information Center

Champagne, Audrey B.; And Others

The research reported in this paper concerns the design of instructional materials that represent the content structure of a science discipline and the development of methods of probing and representing the knowledge structure in a student's memory. The science discipline selected for the study was geology. Specifically, the conceptual structures…

In-vitro engineering of novel bioactivity in the natural enzymes

NASA Astrophysics Data System (ADS)

Tiwari, Vishvanath

2016-10-01

Enzymes catalyze various biochemical functions with high efficiency and specificity. In-vitro design of the enzyme leads to novel bioactivity in this natural biomolecule that give answers of some vital questions like crucial residues in binding with substrate, molecular evolution, cofactor specificity etc. Enzyme engineering technology involves directed evolution, rational designing, semi-rational designing and structure-based designing using chemical modifications. Similarly, combined computational and in-vitro evolution approaches together help in artificial designing of novel bioactivity in the natural enzyme. DNA shuffling, error prone PCR and staggered extension process are used to artificially redesign active site of enzyme, which can alter its efficiency and specificity. Modifications of the enzyme can lead to the discovery of new path of molecular evolution, designing of efficient enzymes, locating active sites and crucial residues, shift in substrate and cofactor specificity. The methods and thermodynamics of in-vitro designing of the enzyme are also discussed. Similarly, engineered thermophilic and psychrophilic enzymes attain substrate specificity and activity of mesophilic enzymes that may also be beneficial for industry and therapeutics.

Self-organization in neural networks - Applications in structural optimization

NASA Technical Reports Server (NTRS)

Hajela, Prabhat; Fu, B.; Berke, Laszlo

1993-01-01

The present paper discusses the applicability of ART (Adaptive Resonance Theory) networks, and the Hopfield and Elastic networks, in problems of structural analysis and design. A characteristic of these network architectures is the ability to classify patterns presented as inputs into specific categories. The categories may themselves represent distinct procedural solution strategies. The paper shows how this property can be adapted in the structural analysis and design problem. A second application is the use of Hopfield and Elastic networks in optimization problems. Of particular interest are problems characterized by the presence of discrete and integer design variables. The parallel computing architecture that is typical of neural networks is shown to be effective in such problems. Results of preliminary implementations in structural design problems are also included in the paper.

Design Study of 8 Meter Monolithic Mirror UV/Optical Space Telescope

NASA Technical Reports Server (NTRS)

Stahl, H. Philip

2008-01-01

The planned Ares V launch vehicle with its 10 meter fairing shroud and 55,000 kg capacity to the Sun Earth L2 point enables entirely new classes of space telescopes. NASA MSFC has conducted a preliminary study that demonstrates the feasibility of launching a 6 to 8 meter class monolithic primary mirror telescope to Sun-Earth L2 using an Ares V. Specific technical areas studied included optical design; structural design/analysis including primary mirror support structure, sun shade and secondary mirror support structure; thermal analysis; launch vehicle performance and trajectory; spacecraft including structure, propulsion, GN&C, avionics, power systems and reaction wheels; operations and servicing; mass and power budgets; and system cost.

Basis of Accreditation for Educational Programs in Designated Health Science Professions.

ERIC Educational Resources Information Center

Canadian Medical Association, Ottawa (Ontario).

Designed as a guide to accreditation for educational programs in designated health science professions in Canada, this report provides educators with guidelines, general requirements, and requirements for specific programs. Following information on the organization, structure, goals, mission, values, philosophy, and terminology of accreditation of…

Integrating aerodynamic surface modeling for computational fluid dynamics with computer aided structural analysis, design, and manufacturing

NASA Technical Reports Server (NTRS)

Thorp, Scott A.

1992-01-01

This presentation will discuss the development of a NASA Geometry Exchange Specification for transferring aerodynamic surface geometry between LeRC systems and grid generation software used for computational fluid dynamics research. The proposed specification is based on a subset of the Initial Graphics Exchange Specification (IGES). The presentation will include discussion of how the NASA-IGES standard will accommodate improved computer aided design inspection methods and reverse engineering techniques currently being developed. The presentation is in viewgraph format.

Structural Design Exploration of an Electric Powered Multi-Propulsor Wing Configuration

NASA Technical Reports Server (NTRS)

Moore, James B.; Cutright, Steve

2017-01-01

Advancements in aircraft electric propulsion may enable an expanded operational envelope for electrically powered vehicles compared to their internal combustion engine counterparts. High aspect ratio wings provide additional lift and drag reduction for a proposed multi-propulsor design, however, the challenge is to reduce the weight of wing structures while maintaining adequate structural and aeroelastic margins. Design exploration using a conventional design-and-build philosophy coupled with a finite element method (FEM)-based design of experiments (DOE) strategy are presented to examine high aspect ratio wing structures that have spanwise distributed electric motors. Multiple leading-edge-mounted engine masses presented a challenge to design a wing within acceptable limits for dynamic and aeroelastic stability. Because the first four primary bending eigenmodes of the proposed wing structure are very sensitive to outboard motor placement, safety-of-flight requirements drove the need for multiple spars, rib attachments, and outboard structural reinforcements in the design. Global aeroelasticity became an increasingly important design constraint during the on-going design process, with outboard motor pod flutter ultimately becoming a primary design constraint. Designers successively generated models to examine stress, dynamics, and aeroelasticity concurrently. This research specifically addressed satisfying multi-disciplinary design criteria to generate fluid-structure interaction solution sets, and produced high aspect ratio primary structure designs for the NASA Scalable Convergent Electric Propulsion Technology and Operations Research (SCEPTOR) project in the Aeronautic Research Mission Directorate at NASA. In this paper, a dynamics-driven, quasi-inverse design methodology is presented to address aerodynamic performance goals and structural challenges encountered for the SCEPTOR demonstrator vehicle. These results are compared with a traditional computer aided design based approach.

49 CFR 179.300 - General specifications applicable to multi-unit tank car tanks designed to be removed from car...

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 3 2013-10-01 2013-10-01 false General specifications applicable to multi-unit tank car tanks designed to be removed from car structure for filling and emptying (Classes DOT-106A and 110AW). 179.300 Section 179.300 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY...

Designing a ticket to ride with the Cognitive Work Analysis Design Toolkit.

PubMed

Read, Gemma J M; Salmon, Paul M; Lenné, Michael G; Jenkins, Daniel P

2015-01-01

Cognitive work analysis has been applied in the design of numerous sociotechnical systems. The process used to translate analysis outputs into design concepts, however, is not always clear. Moreover, structured processes for translating the outputs of ergonomics methods into concrete designs are lacking. This paper introduces the Cognitive Work Analysis Design Toolkit (CWA-DT), a design approach which has been developed specifically to provide a structured means of incorporating cognitive work analysis outputs in design using design principles and values derived from sociotechnical systems theory. This paper outlines the CWA-DT and describes its application in a public transport ticketing design case study. Qualitative and quantitative evaluations of the process provide promising early evidence that the toolkit fulfils the evaluation criteria identified for its success, with opportunities for improvement also highlighted. The Cognitive Work Analysis Design Toolkit has been developed to provide ergonomics practitioners with a structured approach for translating the outputs of cognitive work analysis into design solutions. This paper demonstrates an application of the toolkit and provides evaluation findings.

Overview of NASA/OAST efforts related to manufacturing technology

NASA Technical Reports Server (NTRS)

Saunders, N. T.

1976-01-01

Activities of the Office of Aeronautics and Space Technology (OAST) in a number of areas related to manufacturing technology are considered. In the computer-aided design area improved approaches are developed for the design of specific classes of components or structural subsystems. A generalized approach for the design of a complete aerospace vehicle is also developed. Efforts directed toward an increased use of composite materials in aerospace structures are also discussed and attention is given to projects concerned with the manufacture of turbine engine components.

Computational design of protein antigens that interact with the CDR H3 loop of HIV broadly neutralizing antibody 2F5

PubMed Central

Azoitei, M.L.; Ban, Y.A.; Kalyuzhny, O.; Guenaga, J.; Schroeter, A.; Porter, J.; Wyatt, R.; Schief, W.R.

2015-01-01

Rational design of proteins with novel binding specificities and increased affinity is one of the major goals of computational protein design. Epitope-scaffolds are a new class of antigens engineered by transplanting viral epitopes of pre-defined structure to protein scaffolds, or by building protein scaffolds around such epitopes. Epitope-scaffolds are of interest as vaccine components to attempt to elicit neutralizing antibodies targeting the specified epitope. In this study we developed a new computational protocol, MultiGraft Interface, that transplants epitopes but also designs additional scaffold features outside the epitope to enhance antibody-binding specificity and potentially influence the specificity of elicited antibodies. We employed MultiGraft Interface to engineer novel epitope-scaffolds that display the known epitope of HIV-1 neutralizing antibody 2F5 and that also interact with the functionally important CDR H3 antibody loop. MultiGraft Interface generated an epitope-scaffold that bound 2F5 with sub-nanomolar affinity (KD = 400 pM) and that interacted with the antibody CDR H3 loop through computationally designed contacts. Substantial structural modifications were necessary to engineer this antigen, with the 2F5 epitope replacing a helix in the native scaffold and with 15% of the native scaffold sequence being modified in the design stage. This epitope-scaffold represents a successful example of rational protein backbone engineering and protein-protein interface design and could prove useful in the field of HIV vaccine design. MultiGraft Interface can be generally applied to engineer novel binding partners with altered specificity and optimized affinity. PMID:25043744

In and across bureaucracy: structural and administrative issues for the tobacco endgame.

PubMed

Isett, Kimberley R

2013-05-01

This article assesses the structural choices for the proposed tobacco endgame strategies. I focus on the issues associated with particular structural choices for the location of the implementation. Specifically, I discuss issues related to implementation of the endgame within a specific single agency, and issues related to a more widespread, broad implementation involving several agencies. Where appropriate, I provide examples of how the dynamics discussed would apply to particular endgame strategies. Issues related to design, administration, authority and finances are raised.

In and across bureaucracy: structural and administrative issues for the tobacco endgame

PubMed Central

Isett, Kimberley R

2013-01-01

This article assesses the structural choices for the proposed tobacco endgame strategies. I focus on the issues associated with particular structural choices for the location of the implementation. Specifically, I discuss issues related to implementation of the endgame within a specific single agency, and issues related to a more widespread, broad implementation involving several agencies. Where appropriate, I provide examples of how the dynamics discussed would apply to particular endgame strategies. Issues related to design, administration, authority and finances are raised. PMID:23591514

The design and improvement of radial tire molding machine

NASA Astrophysics Data System (ADS)

Wang, Wenhao; Zhang, Tao

2018-04-01

This paper presented that the high accuracy semisteel meridian tire molding machine structure configurations, combining tyre high precision characteristics, the original structure and parameter optimization, technology improvement innovation design period of opening and closing machine rotary shaping drum institutions. This way out of the shaft from the structure to the push-pull type movable shaping drum of thinking limit, compared with the specifications and shaping drum can smaller contraction, is conducive to forming the tire and reduce the tire deformation.

Economical concrete mix design utilizing blended cements, performance-based specifications, and pay factors.

DOT National Transportation Integrated Search

2013-05-01

This report showcases several new approaches of using materials science and structural mechanics to accomplish : sustainable design of concrete materials. The topics addressed include blended cements, fiber-reinforced concrete : (FRC), internal curin...

Charge-coupled device image sensor study

NASA Technical Reports Server (NTRS)

1973-01-01

The design specifications and predicted performance characteristics of a Charge-Coupled Device Area Imager and a Charge-Coupled Device Linear Imager are presented. The Imagers recommended are intended for use in space-borne imaging systems and therefore would meet the requirements for the intended application. A unique overlapping metal electrode structure and a buried channel structure are described. Reasons for the particular imager designs are discussed.

Rosetta:MSF: a modular framework for multi-state computational protein design.

PubMed

Löffler, Patrick; Schmitz, Samuel; Hupfeld, Enrico; Sterner, Reinhard; Merkl, Rainer

2017-06-01

Computational protein design (CPD) is a powerful technique to engineer existing proteins or to design novel ones that display desired properties. Rosetta is a software suite including algorithms for computational modeling and analysis of protein structures and offers many elaborate protocols created to solve highly specific tasks of protein engineering. Most of Rosetta's protocols optimize sequences based on a single conformation (i. e. design state). However, challenging CPD objectives like multi-specificity design or the concurrent consideration of positive and negative design goals demand the simultaneous assessment of multiple states. This is why we have developed the multi-state framework MSF that facilitates the implementation of Rosetta's single-state protocols in a multi-state environment and made available two frequently used protocols. Utilizing MSF, we demonstrated for one of these protocols that multi-state design yields a 15% higher performance than single-state design on a ligand-binding benchmark consisting of structural conformations. With this protocol, we designed de novo nine retro-aldolases on a conformational ensemble deduced from a (βα)8-barrel protein. All variants displayed measurable catalytic activity, testifying to a high success rate for this concept of multi-state enzyme design.

Rosetta:MSF: a modular framework for multi-state computational protein design

PubMed Central

Hupfeld, Enrico; Sterner, Reinhard

2017-01-01

Computational protein design (CPD) is a powerful technique to engineer existing proteins or to design novel ones that display desired properties. Rosetta is a software suite including algorithms for computational modeling and analysis of protein structures and offers many elaborate protocols created to solve highly specific tasks of protein engineering. Most of Rosetta’s protocols optimize sequences based on a single conformation (i. e. design state). However, challenging CPD objectives like multi-specificity design or the concurrent consideration of positive and negative design goals demand the simultaneous assessment of multiple states. This is why we have developed the multi-state framework MSF that facilitates the implementation of Rosetta’s single-state protocols in a multi-state environment and made available two frequently used protocols. Utilizing MSF, we demonstrated for one of these protocols that multi-state design yields a 15% higher performance than single-state design on a ligand-binding benchmark consisting of structural conformations. With this protocol, we designed de novo nine retro-aldolases on a conformational ensemble deduced from a (βα)8-barrel protein. All variants displayed measurable catalytic activity, testifying to a high success rate for this concept of multi-state enzyme design. PMID:28604768

Stability analysis of truss type highway sign support structures

DOT National Transportation Integrated Search

2000-12-01

The design of truss type sign support structures is based on the guidelines provided by American Association of State Highway and Transportation Officials Standard Specifications for Highway Signs, Luminaires and Traffic Signals and the American Inst...

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

Janjusic, Tommy; Kartsaklis, Christos

Application analysis is facilitated through a number of program profiling tools. The tools vary in their complexity, ease of deployment, design, and profiling detail. Specifically, understand- ing, analyzing, and optimizing is of particular importance for scientific applications where minor changes in code paths and data-structure layout can have profound effects. Understanding how intricate data-structures are accessed and how a given memory system responds is a complex task. In this paper we describe a trace profiling tool, Glprof, specifically aimed to lessen the burden of the programmer to pin-point heavily involved data-structures during an application's run-time, and understand data-structure run-time usage.more » Moreover, we showcase the tool's modularity using additional cache simulation components. We elaborate on the tool's design, and features. Finally we demonstrate the application of our tool in the context of Spec bench- marks using the Glprof profiler and two concurrently running cache simulators, PPC440 and AMD Interlagos.« less

Exploration Planetary Surface Structural Systems: Design Requirements and Compliance

NASA Technical Reports Server (NTRS)

Dorsey, John T.

2011-01-01

The Lunar Surface Systems Project developed system concepts that would be necessary to establish and maintain a permanent human presence on the Lunar surface. A variety of specific system implementations were generated as a part of the scenarios, some level of system definition was completed, and masses estimated for each system. Because the architecture studies generally spawned a large number of system concepts and the studies were executed in a short amount of time, the resulting system definitions had very low design fidelity. This paper describes the development sequence required to field a particular structural system: 1) Define Requirements, 2) Develop the Design and 3) Demonstrate Compliance of the Design to all Requirements. This paper also outlines and describes in detail the information and data that are required to establish structural design requirements and outlines the information that would comprise a planetary surface system Structures Requirements document.

Structure Design Approach and Technology Selection for Next Generation European Launchers

NASA Astrophysics Data System (ADS)

Baiocco, P.; Ramusat, G.; Kauffmann, J.; Jaredson, D.; Bouilly, Th.; Lavelle, F.; Louaas, E.

2012-07-01

In the framework of the next generation launchers activity at ESA, a top-down and a bottom-up approach has been performed for the alternative conception and promising technologies of NGL sub-assemblies and sub-systems. The top-down approach consisted in looking for system-driven design solutions and the bottom-up in the proposal of design solutions taking to substantial advantages for the system. The main investigations have been focused on structures and technologies tight to structures and interfaces. Specifications coming from a preliminary system design have been used in order to permit sub-system design with the goal to find the major advantage for the overall launch system. In this respect selection criteria have been identified and among these a specific evaluation of the payload mass over recurring cost advantage has been evaluated. The development cost, recurring cost and operational aspects have been considered as competitiveness factors for the identification of the most interesting solutions. The TRL/IRL has been assessed and a preliminary development plan has been identified. This approach is dedicated to reference NGL architectures, but alternative architectures have been investigated in order to assess their interest in terms of competitiveness factors and study of other technologies. This paper deals mainly with metallic and composite structures owing to sub-systems or sub-assemblies proposed for the NGL. The major sub-systems and structures analysed are the engine thrust frame (ETF), inter stage structures (ISS), cryogenic propellant tanks, feeding lines and attachments, pressurisation systems and fairing. The paper provides an overview of the main results of this investigation and the potential benefit it can provide.

Compiler writing system detail design specification. Volume 1: Language specification

NASA Technical Reports Server (NTRS)

Arthur, W. J.

1974-01-01

Construction within the Meta language for both language and target machine specification is reported. The elements of the function language as a meaning and syntax are presented, and the structure of the target language is described which represents the target dependent object text representation of applications programs.

Local Structural Differences in Homologous Proteins: Specificities in Different SCOP Classes

PubMed Central

Joseph, Agnel Praveen; Valadié, Hélène; Srinivasan, Narayanaswamy; de Brevern, Alexandre G.

2012-01-01

The constant increase in the number of solved protein structures is of great help in understanding the basic principles behind protein folding and evolution. 3-D structural knowledge is valuable in designing and developing methods for comparison, modelling and prediction of protein structures. These approaches for structure analysis can be directly implicated in studying protein function and for drug design. The backbone of a protein structure favours certain local conformations which include α-helices, β-strands and turns. Libraries of limited number of local conformations (Structural Alphabets) were developed in the past to obtain a useful categorization of backbone conformation. Protein Block (PB) is one such Structural Alphabet that gave a reasonable structure approximation of 0.42 Å. In this study, we use PB description of local structures to analyse conformations that are preferred sites for structural variations and insertions, among group of related folds. This knowledge can be utilized in improving tools for structure comparison that work by analysing local structure similarities. Conformational differences between homologous proteins are known to occur often in the regions comprising turns and loops. Interestingly, these differences are found to have specific preferences depending upon the structural classes of proteins. Such class-specific preferences are mainly seen in the all-β class with changes involving short helical conformations and hairpin turns. A test carried out on a benchmark dataset also indicates that the use of knowledge on the class specific variations can improve the performance of a PB based structure comparison approach. The preference for the indel sites also seem to be confined to a few backbone conformations involving β-turns and helix C-caps. These are mainly associated with short loops joining the regular secondary structures that mediate a reversal in the chain direction. Rare β-turns of type I’ and II’ are also identified as preferred sites for insertions. PMID:22745680

78 FR 12037 - Announcement of the American Petroleum Institute's Standards Activities

Federal Register 2010, 2011, 2012, 2013, 2014

2013-02-21

... Execution, 1st Edition Standard 2CCU, Offshore Cargo Container Design, Manufacturing and Inspection, 1st... Integrity Management of Fixed Offshore Structures, 1st Edition Recommended Practice 2SM, Design, Manufacture... Offshore Production Platforms, 8th Edition Specification 14F, Design and Installation of Electrical Systems...

Substructure-based control of flexible structures

NASA Technical Reports Server (NTRS)

Babuska, Vit; Craig, Roy R., Jr.

1993-01-01

A decentralized procedure is presented for the design of controllers for flexible structures. Spatially significant components are created which approximate the response of a specific part of the complete structure. For each component, the controller and observer gain matrices which are used in a controller for the complete structure. The proposed method is illustrated on a model of NASA Langley's CSI testbed structure.

A comparative study of internally and externally capped balloons using small scale test balloons

NASA Technical Reports Server (NTRS)

Bell, Douglas P.

1994-01-01

Caps have been used to structurally reinforce scientific research balloons since the late 1950's. The scientific research balloons used by the National Aeronautics and Space Administration (NASA) use internal caps. A NASA cap placement specification does not exist since no empirical information exisits concerning cap placement. To develop a cap placement specification, NASA has completed two in-hangar inflation tests comparing the structural contributions of internal caps and external caps. The tests used small scale test balloons designed to develop the highest possible stresses within the constraints of the hangar and balloon materials. An externally capped test balloon and an internally capped test balloon were designed, built, inflated and simulated to determine the structural contributions and benefits of each. The results of the tests and simulations are presented.

The effects of design details on cost and weight of fuselage structures

NASA Technical Reports Server (NTRS)

Swanson, G. D.; Metschan, S. L.; Morris, M. R.; Kassapoglou, C.

1993-01-01

Crown panel design studies showing the relationship between panel size, cost, weight, and aircraft configuration are compared to aluminum design configurations. The effects of a stiffened sandwich design concept are also discussed. This paper summarizes the effect of a design cost model in assessing the cost and weight relationships for fuselage crown panel designs. Studies were performed using data from existing aircraft to assess the effects of different design variables on the cost and weight of transport fuselage crown panel design. Results show a strong influence of load levels, panel size, and material choices on the cost and weight of specific designs. A design tool being developed under the NASA ACT program is used in the study to assess these issues. The effects of panel configuration comparing postbuckled and buckle resistant stiffened laminated structure is compared to a stiffened sandwich concept. Results suggest some potential economy with stiffened sandwich designs for compression dominated structure with relatively high load levels.

Tools reference manual for a Requirements Specification Language (RSL), version 2.0

NASA Technical Reports Server (NTRS)

Fisher, Gene L.; Cohen, Gerald C.

1993-01-01

This report describes a general-purpose Requirements Specification Language, RSL. The purpose of RSL is to specify precisely the external structure of a mechanized system and to define requirements that the system must meet. A system can be comprised of a mixture of hardware, software, and human processing elements. RSL is a hybrid of features found in several popular requirements specification languages, such as SADT (Structured Analysis and Design Technique), PSL (Problem Statement Language), and RMF (Requirements Modeling Framework). While languages such as these have useful features for structuring a specification, they generally lack formality. To overcome the deficiencies of informal requirements languages, RSL has constructs for formal mathematical specification. These constructs are similar to those found in formal specification languages such as EHDM (Enhanced Hierarchical Development Methodology), Larch, and OBJ3.

Predicting Silk Fiber Mechanical Properties through Multiscale Simulation and Protein Design.

PubMed

Rim, Nae-Gyune; Roberts, Erin G; Ebrahimi, Davoud; Dinjaski, Nina; Jacobsen, Matthew M; Martín-Moldes, Zaira; Buehler, Markus J; Kaplan, David L; Wong, Joyce Y

2017-08-14

Silk is a promising material for biomedical applications, and much research is focused on how application-specific, mechanical properties of silk can be designed synthetically through proper amino acid sequences and processing parameters. This protocol describes an iterative process between research disciplines that combines simulation, genetic synthesis, and fiber analysis to better design silk fibers with specific mechanical properties. Computational methods are used to assess the protein polymer structure as it forms an interconnected fiber network through shearing and how this process affects fiber mechanical properties. Model outcomes are validated experimentally with the genetic design of protein polymers that match the simulation structures, fiber fabrication from these polymers, and mechanical testing of these fibers. Through iterative feedback between computation, genetic synthesis, and fiber mechanical testing, this protocol will enable a priori prediction capability of recombinant material mechanical properties via insights from the resulting molecular architecture of the fiber network based entirely on the initial protein monomer composition. This style of protocol may be applied to other fields where a research team seeks to design a biomaterial with biomedical application-specific properties. This protocol highlights when and how the three research groups (simulation, synthesis, and engineering) should be interacting to arrive at the most effective method for predictive design of their material.

Formulation of advanced consumables management models: Environmental control and electrical power system performance models requirements

NASA Technical Reports Server (NTRS)

Daly, J. K.; Torian, J. G.

1979-01-01

Software design specifications for developing environmental control and life support system (ECLSS) and electrical power system (EPS) programs into interactive computer programs are presented. Specifications for the ECLSS program are at the detail design level with respect to modification of an existing batch mode program. The FORTRAN environmental analysis routines (FEAR) are the subject batch mode program. The characteristics of the FEAR program are included for use in modifying batch mode programs to form interactive programs. The EPS program specifications are at the preliminary design level. Emphasis is on top-down structuring in the development of an interactive program.

Development and evaluation of task-specific NLP framework in China.

PubMed

Ge, Caixia; Zhang, Yinsheng; Huang, Zhenzhen; Jia, Zheng; Ju, Meizhi; Duan, Huilong; Li, Haomin

2015-01-01

Natural language processing (NLP) has been designed to convert narrative text into structured data. Although some general NLP architectures have been developed, a task-specific NLP framework to facilitate the effective use of data is still a challenge in lexical resource limited regions, such as China. The purpose of this study is to design and develop a task-specific NLP framework to extract targeted information from particular documents by adopting dedicated algorithms on current limited lexical resources. In this framework, a shared and evolving ontology mechanism was designed. The result has shown that such a free text driven platform will accelerate the NLP technology acceptance in China.

Discrete size optimization of steel trusses using a refined big bang-big crunch algorithm

NASA Astrophysics Data System (ADS)

Hasançebi, O.; Kazemzadeh Azad, S.

2014-01-01

This article presents a methodology that provides a method for design optimization of steel truss structures based on a refined big bang-big crunch (BB-BC) algorithm. It is shown that a standard formulation of the BB-BC algorithm occasionally falls short of producing acceptable solutions to problems from discrete size optimum design of steel trusses. A reformulation of the algorithm is proposed and implemented for design optimization of various discrete truss structures according to American Institute of Steel Construction Allowable Stress Design (AISC-ASD) specifications. Furthermore, the performance of the proposed BB-BC algorithm is compared to its standard version as well as other well-known metaheuristic techniques. The numerical results confirm the efficiency of the proposed algorithm in practical design optimization of truss structures.

BILL-E: Robotic Platform for Locomotion and Manipulation of Lightweight Space Structures

NASA Technical Reports Server (NTRS)

Jenett, Benjamin; Cheung, Kenneth

2017-01-01

We describe a robotic platform for traversing and manipulating a modular 3D lattice structure. The robot is designed to operate within a specifically structured environment, which enables low numbers of degrees of freedom (DOF) compared to robots performing comparable tasks in an unstructured environment. This allows for simple controls, as well as low mass and cost. This approach, designing the robot relative to the local environment in which it operates, results in a type of robot we call a "relative robot." We describe a bipedal robot that can locomote across a periodic lattice structure, as well as being able to handle, manipulate, and transport building block parts that compose the lattice structure. Based on a general inchworm design, the robot has added functionality for traveling over and operating on a host structure.

Structural Insights into the Molecular Design of Flutolanil Derivatives Targeted for Fumarate Respiration of Parasite Mitochondria.

PubMed

Inaoka, Daniel Ken; Shiba, Tomoo; Sato, Dan; Balogun, Emmanuel Oluwadare; Sasaki, Tsuyoshi; Nagahama, Madoka; Oda, Masatsugu; Matsuoka, Shigeru; Ohmori, Junko; Honma, Teruki; Inoue, Masayuki; Kita, Kiyoshi; Harada, Shigeharu

2015-07-07

Recent studies on the respiratory chain of Ascaris suum showed that the mitochondrial NADH-fumarate reductase system composed of complex I, rhodoquinone and complex II plays an important role in the anaerobic energy metabolism of adult A. suum. The system is the major pathway of energy metabolism for adaptation to a hypoxic environment not only in parasitic organisms, but also in some types of human cancer cells. Thus, enzymes of the pathway are potential targets for chemotherapy. We found that flutolanil is an excellent inhibitor for A. suum complex II (IC50 = 0.058 μM) but less effectively inhibits homologous porcine complex II (IC50 = 45.9 μM). In order to account for the specificity of flutolanil to A. suum complex II from the standpoint of structural biology, we determined the crystal structures of A. suum and porcine complex IIs binding flutolanil and its derivative compounds. The structures clearly demonstrated key interactions responsible for its high specificity to A. suum complex II and enabled us to find analogue compounds, which surpass flutolanil in both potency and specificity to A. suum complex II. Structures of complex IIs binding these compounds will be helpful to accelerate structure-based drug design targeted for complex IIs.

Structural Insights into the Molecular Design of Flutolanil Derivatives Targeted for Fumarate Respiration of Parasite Mitochondria

PubMed Central

Inaoka, Daniel Ken; Shiba, Tomoo; Sato, Dan; Balogun, Emmanuel Oluwadare; Sasaki, Tsuyoshi; Nagahama, Madoka; Oda, Masatsugu; Matsuoka, Shigeru; Ohmori, Junko; Honma, Teruki; Inoue, Masayuki; Kita, Kiyoshi; Harada, Shigeharu

2015-01-01

Recent studies on the respiratory chain of Ascaris suum showed that the mitochondrial NADH-fumarate reductase system composed of complex I, rhodoquinone and complex II plays an important role in the anaerobic energy metabolism of adult A. suum. The system is the major pathway of energy metabolism for adaptation to a hypoxic environment not only in parasitic organisms, but also in some types of human cancer cells. Thus, enzymes of the pathway are potential targets for chemotherapy. We found that flutolanil is an excellent inhibitor for A. suum complex II (IC50 = 0.058 μM) but less effectively inhibits homologous porcine complex II (IC50 = 45.9 μM). In order to account for the specificity of flutolanil to A. suum complex II from the standpoint of structural biology, we determined the crystal structures of A. suum and porcine complex IIs binding flutolanil and its derivative compounds. The structures clearly demonstrated key interactions responsible for its high specificity to A. suum complex II and enabled us to find analogue compounds, which surpass flutolanil in both potency and specificity to A. suum complex II. Structures of complex IIs binding these compounds will be helpful to accelerate structure-based drug design targeted for complex IIs. PMID:26198225

Ascent performance feasibility for next-generation spacecraft

NASA Astrophysics Data System (ADS)

Mancuso, Salvatore Massimo

This thesis deals with the optimization of the ascent trajectories for single-stage suborbital (SSSO), single-stage-to-orbit (SSTO), and two-stage-to-orbit (TSTO) rocket-powered spacecraft. The maximum payload weight problem has been solved using the sequential gradient-restoration algorithm. For the TSTO case, some modifications to the original version of the algorithm have been necessary in order to deal with discontinuities due to staging and the fact that the functional being minimized depends on interface conditions. The optimization problem is studied for different values of the initial thrust-to-weight ratio in the range 1.3 to 1.6, engine specific impulse in the range 400 to 500 sec, and spacecraft structural factor in the range 0.08 to 0.12. For the TSTO configuration, two subproblems are studied: uniform structural factor between stages and nonuniform structural factor between stages. Due to the regular behavior of the results obtained, engineering approximations have been developed which connect the maximum payload weight to the engine specific impulse and spacecraft structural factor; in turn, this leads to useful design considerations. Also, performance sensitivity to the scale of the aerodynamic drag is studied, and it is shown that its effect on payload weight is relatively small, even for drag changes approaching ± 50%. The main conclusions are that: the design of a SSSO configuration appears to be feasible; the design of a SSTO configuration might be comfortably feasible, marginally feasible, or unfeasible, depending on the parameter values assumed; the design of a TSTO configuration is not only feasible, but its payload appears to be considerably larger than that of a SSTO configuration. Improvements in engine specific impulse and spacecraft structural factor are desirable and crucial for SSTO feasibility; indeed, it appears that aerodynamic improvements do not yield significant improvements in payload weight.

Crashworthiness Design for Bionic Bumper Structures Inspired by Cattail and Bamboo.

PubMed

Xu, Tao; Liu, Nian; Yu, Zhenglei; Xu, Tianshuang; Zou, Meng

2017-01-01

Many materials in nature exhibit excellent mechanical properties. In this study, we evaluated the bionic bumper structure models by using nonlinear finite element (FE) simulations for their crashworthiness under full-size impact loading. The structure contained the structural characteristics of cattail and bamboo. The results indicated that the bionic design enhances the specific energy absorption (SEA) of the bumper. The numerical results showed that the bionic cross-beam and bionic box of the bionic bumper have a significant effect on the crashworthiness of the structure. The crush deformation of bionic cross-beam and box bumper model was reduced by 33.33%, and the total weight was reduced by 44.44%. As the energy absorption capacity under lateral impact, the bionic design can be used in the future bumper body.

Crashworthiness Design for Bionic Bumper Structures Inspired by Cattail and Bamboo

PubMed Central

Xu, Tao; Liu, Nian

2017-01-01

Many materials in nature exhibit excellent mechanical properties. In this study, we evaluated the bionic bumper structure models by using nonlinear finite element (FE) simulations for their crashworthiness under full-size impact loading. The structure contained the structural characteristics of cattail and bamboo. The results indicated that the bionic design enhances the specific energy absorption (SEA) of the bumper. The numerical results showed that the bionic cross-beam and bionic box of the bionic bumper have a significant effect on the crashworthiness of the structure. The crush deformation of bionic cross-beam and box bumper model was reduced by 33.33%, and the total weight was reduced by 44.44%. As the energy absorption capacity under lateral impact, the bionic design can be used in the future bumper body. PMID:29118571

Charge-transfer-based terbium MOF nanoparticles as fluorescent pH sensor for extreme acidity.

PubMed

Qi, Zewan; Chen, Yang

2017-01-15

Newly emerged metal organic frameworks (MOFs) have aroused the great interest in designing functional materials by means of its flexible structure and component. In this study, we used lanthanide Tb 3+ ions and small molecular ligands to design and assemble a kind of pH-sensitive MOF nanoparticle based on intramolecular-charge-transfer effect. This kind of made-to-order MOF nanoparticle for H + is highly specific and sensitive and could be used to fluorescently indicate pH value of strong acidic solution via preset mechanism through luminescence of Tb 3+ . The long luminescence lifetime of Tb 3+ allows eliminating concomitant non-specific fluorescence by time-revised fluorescence techniques, processing an advantage in sensing H + in biological media with strong autofluorescence. Our method showed a great potential of MOF structures in designing and constructing sensitive sensing materials for specific analytes directly via the assembly of functional ions/ligands. Copyright © 2016 Elsevier B.V. All rights reserved.

Automating software design system DESTA

NASA Technical Reports Server (NTRS)

Lovitsky, Vladimir A.; Pearce, Patricia D.

1992-01-01

'DESTA' is the acronym for the Dialogue Evolutionary Synthesizer of Turnkey Algorithms by means of a natural language (Russian or English) functional specification of algorithms or software being developed. DESTA represents the computer-aided and/or automatic artificial intelligence 'forgiving' system which provides users with software tools support for algorithm and/or structured program development. The DESTA system is intended to provide support for the higher levels and earlier stages of engineering design of software in contrast to conventional Computer Aided Design (CAD) systems which provide low level tools for use at a stage when the major planning and structuring decisions have already been taken. DESTA is a knowledge-intensive system. The main features of the knowledge are procedures, functions, modules, operating system commands, batch files, their natural language specifications, and their interlinks. The specific domain for the DESTA system is a high level programming language like Turbo Pascal 6.0. The DESTA system is operational and runs on an IBM PC computer.

Development of a domain-specific genetic language to design Chlamydomonas reinhardtii expression vectors.

PubMed

Wilson, Mandy L; Okumoto, Sakiko; Adam, Laura; Peccoud, Jean

2014-01-15

Expression vectors used in different biotechnology applications are designed with domain-specific rules. For instance, promoters, origins of replication or homologous recombination sites are host-specific. Similarly, chromosomal integration or viral delivery of an expression cassette imposes specific structural constraints. As de novo gene synthesis and synthetic biology methods permeate many biotechnology specialties, the design of application-specific expression vectors becomes the new norm. In this context, it is desirable to formalize vector design strategies applicable in different domains. Using the design of constructs to express genes in the chloroplast of Chlamydomonas reinhardtii as an example, we show that a vector design strategy can be formalized as a domain-specific language. We have developed a graphical editor of context-free grammars usable by biologists without prior exposure to language theory. This environment makes it possible for biologists to iteratively improve their design strategies throughout the course of a project. It is also possible to ensure that vectors designed with early iterations of the language are consistent with the latest iteration of the language. The context-free grammar editor is part of the GenoCAD application. A public instance of GenoCAD is available at http://www.genocad.org. GenoCAD source code is available from SourceForge and licensed under the Apache v2.0 open source license.

Safety and design in airplane construction

NASA Technical Reports Server (NTRS)

Teichmann, Alfred

1934-01-01

The author gives a survey of the principles of stress analysis and design of airplane structures, and discusses the fundamental strength specifications and their effect on the stress analysis as compared with the safety factors used in other branches of engineering.

Flood type specific construction of synthetic design hydrographs

NASA Astrophysics Data System (ADS)

Brunner, Manuela I.; Viviroli, Daniel; Sikorska, Anna E.; Vannier, Olivier; Favre, Anne-Catherine; Seibert, Jan

2017-02-01

Accurate estimates of flood peaks, corresponding volumes, and hydrographs are required to design safe and cost-effective hydraulic structures. In this paper, we propose a statistical approach for the estimation of the design variables peak and volume by constructing synthetic design hydrographs for different flood types such as flash-floods, short-rain floods, long-rain floods, and rain-on-snow floods. Our approach relies on the fitting of probability density functions to observed flood hydrographs of a certain flood type and accounts for the dependence between peak discharge and flood volume. It makes use of the statistical information contained in the data and retains the process information of the flood type. The method was tested based on data from 39 mesoscale catchments in Switzerland and provides catchment specific and flood type specific synthetic design hydrographs for all of these catchments. We demonstrate that flood type specific synthetic design hydrographs are meaningful in flood-risk management when combined with knowledge on the seasonality and the frequency of different flood types.

A Mobile Robot for Locomotion Through a 3D Periodic Lattice Environment

NASA Technical Reports Server (NTRS)

Jenett, Benjamin; Cellucci, Daniel; Cheung, Kenneth

2017-01-01

This paper describes a novel class of robots specifically adapted to climb periodic lattices, which we call 'Relative Robots'. These robots use the regularity of the structure to simplify the path planning, align with minimal feedback, and reduce the number of degrees of freedom (DOF) required to locomote. They can perform vital inspection and repair tasks within the structure that larger truss construction robots could not perform without modifying the structure. We detail a specific type of relative robot designed to traverse a cuboctahedral (CubOct) cellular solids lattice, show how the symmetries of the lattice simplify the design, and test these design methodologies with a CubOct relative robot that traverses a 76.2 mm (3 in.) pitch lattice, MOJO (Multi-Objective JOurneying robot). We perform three locomotion tasks with MOJO: vertical climbing, horizontal climbing, and turning, and find that, due to changes in the orientation of the robot relative to the gravity vector, the success rate of vertical and horizontal climbing is significantly different.

Conceptual design of ACB-CP for ITER cryogenic system

NASA Astrophysics Data System (ADS)

Jiang, Yongcheng; Xiong, Lianyou; Peng, Nan; Tang, Jiancheng; Liu, Liqiang; Zhang, Liang

2012-06-01

ACB-CP (Auxiliary Cold Box for Cryopumps) is used to supply the cryopumps system with necessary cryogen in ITER (International Thermonuclear Experimental Reactor) cryogenic distribution system. The conceptual design of ACB-CP contains thermo-hydraulic analysis, 3D structure design and strength checking. Through the thermohydraulic analysis, the main specifications of process valves, pressure safety valves, pipes, heat exchangers can be decided. During the 3D structure design process, vacuum requirement, adiabatic requirement, assembly constraints and maintenance requirement have been considered to arrange the pipes, valves and other components. The strength checking has been performed to crosscheck if the 3D design meets the strength requirements for the ACB-CP.

Methods for Combining Payload Parameter Variations with Input Environment

NASA Technical Reports Server (NTRS)

Merchant, D. H.; Straayer, J. W.

1975-01-01

Methods are presented for calculating design limit loads compatible with probabilistic structural design criteria. The approach is based on the concept that the desired limit load, defined as the largest load occuring in a mission, is a random variable having a specific probability distribution which may be determined from extreme-value theory. The design limit load, defined as a particular value of this random limit load, is the value conventionally used in structural design. Methods are presented for determining the limit load probability distributions from both time-domain and frequency-domain dynamic load simulations. Numerical demonstrations of the methods are also presented.

Facesheet Wrinkling in Sandwich Structures

NASA Technical Reports Server (NTRS)

Ley, Robert P.; Lin, Weichuan; Mbanefo, Uy

1999-01-01

The purpose of this paper is to provide a concise summary of the state-of-the-art for the analysis of the facesheet wrinkling mode of failure in sandwich structures. This document is not an exhaustive review of the published research related to facesheet wrinkling. Instead, a smaller number of key papers are reviewed in order to provide designers and analysts with a working understanding of the state-of-the-art. Designers and analysts should use this survey to guide their judgement when deciding which one of a wide variety of available facesheet wrinkling design formulas is applicable to a specific design problem.

HAL/SM system functional design specification. [systems analysis and design analysis of central processing units

NASA Technical Reports Server (NTRS)

Ross, C.; Williams, G. P. W., Jr.

1975-01-01

The functional design of a preprocessor, and subsystems is described. A structure chart and a data flow diagram are included for each subsystem. Also a group of intermodule interface definitions (one definition per module) is included immediately following the structure chart and data flow for a particular subsystem. Each of these intermodule interface definitions consists of the identification of the module, the function the module is to perform, the identification and definition of parameter interfaces to the module, and any design notes associated with the module. Also described are compilers and computer libraries.

Structural test of the parameterized-backbone method for protein design.

PubMed

Plecs, Joseph J; Harbury, Pehr B; Kim, Peter S; Alber, Tom

2004-09-03

Designing new protein folds requires a method for simultaneously optimizing the conformation of the backbone and the side-chains. One approach to this problem is the use of a parameterized backbone, which allows the systematic exploration of families of structures. We report the crystal structure of RH3, a right-handed, three-helix coiled coil that was designed using a parameterized backbone and detailed modeling of core packing. This crystal structure was determined using another rationally designed feature, a metal-binding site that permitted experimental phasing of the X-ray data. RH3 adopted the intended fold, which has not been observed previously in biological proteins. Unanticipated structural asymmetry in the trimer was a principal source of variation within the RH3 structure. The sequence of RH3 differs from that of a previously characterized right-handed tetramer, RH4, at only one position in each 11 amino acid sequence repeat. This close similarity indicates that the design method is sensitive to the core packing interactions that specify the protein structure. Comparison of the structures of RH3 and RH4 indicates that both steric overlap and cavity formation provide strong driving forces for oligomer specificity.

An expert system for integrated structural analysis and design optimization for aerospace structures

NASA Technical Reports Server (NTRS)

1992-01-01

The results of a research study on the development of an expert system for integrated structural analysis and design optimization is presented. An Object Representation Language (ORL) was developed first in conjunction with a rule-based system. This ORL/AI shell was then used to develop expert systems to provide assistance with a variety of structural analysis and design optimization tasks, in conjunction with procedural modules for finite element structural analysis and design optimization. The main goal of the research study was to provide expertise, judgment, and reasoning capabilities in the aerospace structural design process. This will allow engineers performing structural analysis and design, even without extensive experience in the field, to develop error-free, efficient and reliable structural designs very rapidly and cost-effectively. This would not only improve the productivity of design engineers and analysts, but also significantly reduce time to completion of structural design. An extensive literature survey in the field of structural analysis, design optimization, artificial intelligence, and database management systems and their application to the structural design process was first performed. A feasibility study was then performed, and the architecture and the conceptual design for the integrated 'intelligent' structural analysis and design optimization software was then developed. An Object Representation Language (ORL), in conjunction with a rule-based system, was then developed using C++. Such an approach would improve the expressiveness for knowledge representation (especially for structural analysis and design applications), provide ability to build very large and practical expert systems, and provide an efficient way for storing knowledge. Functional specifications for the expert systems were then developed. The ORL/AI shell was then used to develop a variety of modules of expert systems for a variety of modeling, finite element analysis, and design optimization tasks in the integrated aerospace structural design process. These expert systems were developed to work in conjunction with procedural finite element structural analysis and design optimization modules (developed in-house at SAT, Inc.). The complete software, AutoDesign, so developed, can be used for integrated 'intelligent' structural analysis and design optimization. The software was beta-tested at a variety of companies, used by a range of engineers with different levels of background and expertise. Based on the feedback obtained by such users, conclusions were developed and are provided.

An expert system for integrated structural analysis and design optimization for aerospace structures

NASA Astrophysics Data System (ADS)

1992-04-01

The results of a research study on the development of an expert system for integrated structural analysis and design optimization is presented. An Object Representation Language (ORL) was developed first in conjunction with a rule-based system. This ORL/AI shell was then used to develop expert systems to provide assistance with a variety of structural analysis and design optimization tasks, in conjunction with procedural modules for finite element structural analysis and design optimization. The main goal of the research study was to provide expertise, judgment, and reasoning capabilities in the aerospace structural design process. This will allow engineers performing structural analysis and design, even without extensive experience in the field, to develop error-free, efficient and reliable structural designs very rapidly and cost-effectively. This would not only improve the productivity of design engineers and analysts, but also significantly reduce time to completion of structural design. An extensive literature survey in the field of structural analysis, design optimization, artificial intelligence, and database management systems and their application to the structural design process was first performed. A feasibility study was then performed, and the architecture and the conceptual design for the integrated 'intelligent' structural analysis and design optimization software was then developed. An Object Representation Language (ORL), in conjunction with a rule-based system, was then developed using C++. Such an approach would improve the expressiveness for knowledge representation (especially for structural analysis and design applications), provide ability to build very large and practical expert systems, and provide an efficient way for storing knowledge. Functional specifications for the expert systems were then developed. The ORL/AI shell was then used to develop a variety of modules of expert systems for a variety of modeling, finite element analysis, and design optimization tasks in the integrated aerospace structural design process. These expert systems were developed to work in conjunction with procedural finite element structural analysis and design optimization modules (developed in-house at SAT, Inc.). The complete software, AutoDesign, so developed, can be used for integrated 'intelligent' structural analysis and design optimization. The software was beta-tested at a variety of companies, used by a range of engineers with different levels of background and expertise. Based on the feedback obtained by such users, conclusions were developed and are provided.

Fracture control procedures for aircraft structural integrity

NASA Technical Reports Server (NTRS)

Wood, H. A.

1972-01-01

The application of applied fracture mechanics in the design, analysis, and qualification of aircraft structural systems are reviewed. Recent service experiences are cited. Current trends in high-strength materials application are reviewed with particular emphasis on the manner in which fracture toughness and structural efficiency may affect the material selection process. General fracture control procedures are reviewed in depth with specific reference to the impact of inspectability, structural arrangement, and material on proposed analysis requirements for safe crack growth. The relative impact on allowable design stress is indicated by example. Design criteria, material, and analysis requirements for implementation of fracture control procedures are reviewed together with limitations in current available data techniques. A summary of items which require further study and attention is presented.

Evaluation of beryllium for space shuttle components

NASA Technical Reports Server (NTRS)

Trapp, A. E.

1972-01-01

Application of beryllium to specific full-scale space shuttle structural components and assemblies was studied. Material evaluations were conducted to check the mechanical properties of as-received material to gain design information on characteristics needed for the material in the space shuttle environment, and to obtain data needed for evaluating component and panel tests. Four beryllium structural assemblies were analyzed and designed. Selected components of these assemblies, representing areas of critical loading or design/process uncertainty, were designed and tested, and two panel assemblies were fabricated. Trends in cost and weight factors were determined by progressive estimation at key points of preliminary design, final design, and fabrication to aid in a cost/weight evaluation of the use of beryllium.

Realization of FRC interior and exterior furniture

NASA Astrophysics Data System (ADS)

Šonka, Š.; Frantová, M.; Štemberk, P.; Havrda, J.; Janouch, P.

2017-09-01

This article deals with the implementation of fibre reinforced concrete for interior and exterior furniture. The use of fibre reinforced concrete for non-traditional and small structures brings some specifics in design and realization. These are, in particular, the design of a suitable mixture, the choice of the shape of the structure in relation to the technological possibilities of realization, the static effects and finally the actual production of the element.

Airborne remote sensors applied to engineering geology and civil works design investigations

NASA Technical Reports Server (NTRS)

Gelnett, R. H.

1975-01-01

The usefulness of various airborne remote sensing systems in the detection and identification of regional and specific geologic structural features that may affect the design and location of engineering structures on major civil works projects is evaluated. The Butler Valley Dam and Blue Lake Project in northern California was selected as a demonstration site. Findings derived from the interpretation of various kinds of imagery used are given.

Decoupling local mechanics from large-scale structure in modular metamaterials.

PubMed

Yang, Nan; Silverberg, Jesse L

2017-04-04

A defining feature of mechanical metamaterials is that their properties are determined by the organization of internal structure instead of the raw fabrication materials. This shift of attention to engineering internal degrees of freedom has coaxed relatively simple materials into exhibiting a wide range of remarkable mechanical properties. For practical applications to be realized, however, this nascent understanding of metamaterial design must be translated into a capacity for engineering large-scale structures with prescribed mechanical functionality. Thus, the challenge is to systematically map desired functionality of large-scale structures backward into a design scheme while using finite parameter domains. Such "inverse design" is often complicated by the deep coupling between large-scale structure and local mechanical function, which limits the available design space. Here, we introduce a design strategy for constructing 1D, 2D, and 3D mechanical metamaterials inspired by modular origami and kirigami. Our approach is to assemble a number of modules into a voxelized large-scale structure, where the module's design has a greater number of mechanical design parameters than the number of constraints imposed by bulk assembly. This inequality allows each voxel in the bulk structure to be uniquely assigned mechanical properties independent from its ability to connect and deform with its neighbors. In studying specific examples of large-scale metamaterial structures we show that a decoupling of global structure from local mechanical function allows for a variety of mechanically and topologically complex designs.

U.S. perspective on technology demonstration experiments for adaptive structures

NASA Technical Reports Server (NTRS)

Aswani, Mohan; Wada, Ben K.; Garba, John A.

1991-01-01

Evaluation of design concepts for adaptive structures is being performed in support of several focused research programs. These include programs such as Precision Segmented Reflector (PSR), Control Structure Interaction (CSI), and the Advanced Space Structures Technology Research Experiment (ASTREX). Although not specifically designed for adaptive structure technology validation, relevant experiments can be performed using the Passive and Active Control of Space Structures (PACOSS) testbed, the Space Integrated Controls Experiment (SPICE), the CSI Evolutionary Model (CEM), and the Dynamic Scale Model Test (DSMT) Hybrid Scale. In addition to the ground test experiments, several space flight experiments have been planned, including a reduced gravity experiment aboard the KC-135 aircraft, shuttle middeck experiments, and the Inexpensive Flight Experiment (INFLEX).

Implementation of civionics in a second generation steel-free bridge deck

NASA Astrophysics Data System (ADS)

Klowak, Chad; Rivera, Evangeline; Mufti, Aftab

2005-05-01

As the design and construction of civil structures continue to evolve, it is becoming imperative that these structures be monitored for their health. In order to meet this need, the discipline of Civionics has emerged. Civionics is a new term coined from Civil-Electronics, which is derived from the application of electronics to civil structures. It is similar to the term Avionics, which is used in the aerospace industry. If structural health monitoring is to become part of civil structural engineering, it should include Civionics. It involves the application of electronics to civil structures and aims to assist engineers in realizing the full benefits of structural health monitoring (SHM). In past SHM field applications, the main reason for the failure of a sensor was not the installation of the sensor itself but the egress of the sensor cables. Often, the cables were not handled and protected correctly. For SHM to be successful, specifications must be written on the entire process, beginning with system design and concluding with data collection, interpretation, and management. Civionics specifications include the technical requirements for a SHM system which encompasses fibre optic sensors, cables, conduits, junction boxes and the control room. A specification for data collection and storage is currently being developed as well. In the spring of 2004 research engineers at the University of Manitoba constructed a full-scale second generation steel free bridge deck. The bridge deck is the first of its kind to fully incorporate a complete civionics structural health monitoring system to monitor the deck's behaviour during destructive testing. Throughout the construction of the bridge deck, the entire installation of the civionics system was carried out by research engineers simulating an actual implementation of such a system in a large scale construction environment. One major concern that consulting engineers have raised is the impact that a civionics system that uses conduit, junction boxes, and other electrical ancillary protection, will have when embedded and installed externally on full-scale infrastructure. The full-scale destructive testing of a second generation steel-free bridge deck using a civionics system designed and implemented following guidelines in a civioncs specification manual at the University of Manitoba will provide engineers with the information necessary to address the constructability and structural integrity issues. Civioncs combined with structural health monitoring will provide engineers with feedback necessary to aid in optimizing design techniques and understanding our infrastructures performance, behaviour and state of condition.

Field measurements on skewed semi-integral bridge with elastic inclusion : instrumentation report.

DOT National Transportation Integrated Search

2006-01-01

This project was designed to enhance the Virginia Department of Transportation's expertise in the design of integral bridges, particularly as it applies to highly skewed structures. Specifically, the project involves extensive monitoring of a semi-in...

Development of traffic data input resources for the mechanistic empirical pavement design process.

DOT National Transportation Integrated Search

2011-12-12

The Mechanistic-Empirical Pavement Design Guide (MEPDG) for New and Rehabilitated Pavement Structures uses : nationally based data traffic inputs and recommends that state DOTs develop their own site-specific and regional : values. To support the MEP...

Embedded data collector (EDC) phase II load and resistance factor design (LRFD) : [summary].

DOT National Transportation Integrated Search

2015-07-01

Piles that support bridge structures are designed for the specific site characteristics and loads : that the piles are expected to bear. In Florida, driven piles are monitored during installation : (dynamically tested) to assess resistance, com...

South Florida Freight Advanced Traveler Information System : architecture and implementation options summary report.

DOT National Transportation Integrated Search

2013-07-01

This Final Architecture and Design report has been prepared to describe the structure and design of all the system components for the South Florida FRATIS Demonstration Project. More specifically, this document provides: Detailed descriptions of ...

The 18th Aerospace Mechanisms Symposium

NASA Technical Reports Server (NTRS)

1984-01-01

Topics concerning aerospace mechanisms, their functional performance, and design specifications are presented. Discussed subjects include the design and development of release mechanisms, actuators, linear driver/rate controllers, antenna and appendage deployment systems, position control systems, and tracking mechanisms for antennas and solar arrays. Engine design, spaceborne experiments, and large space structure technology are also examined.

De novo self-assembling collagen heterotrimers using explicit positive and negative design.

PubMed

Xu, Fei; Zhang, Lei; Koder, Ronald L; Nanda, Vikas

2010-03-23

We sought to computationally design model collagen peptides that specifically associate as heterotrimers. Computational design has been successfully applied to the creation of new protein folds and functions. Despite the high abundance of collagen and its key role in numerous biological processes, fibrous proteins have received little attention as computational design targets. Collagens are composed of three polypeptide chains that wind into triple helices. We developed a discrete computational model to design heterotrimer-forming collagen-like peptides. Stability and specificity of oligomerization were concurrently targeted using a combined positive and negative design approach. The sequences of three 30-residue peptides, A, B, and C, were optimized to favor charge-pair interactions in an ABC heterotrimer, while disfavoring the 26 competing oligomers (i.e., AAA, ABB, BCA). Peptides were synthesized and characterized for thermal stability and triple-helical structure by circular dichroism and NMR. A unique A:B:C-type species was not achieved. Negative design was partially successful, with only A + B and B + C competing mixtures formed. Analysis of computed versus experimental stabilities helps to clarify the role of electrostatics and secondary-structure propensities determining collagen stability and to provide important insight into how subsequent designs can be improved.

ATLAS, an integrated structural analysis and design system. Volume 6: Design module theory

NASA Technical Reports Server (NTRS)

Backman, B. F.

1979-01-01

The automated design theory underlying the operation of the ATLAS Design Module is decribed. The methods, applications and limitations associated with the fully stressed design, the thermal fully stressed design and a regional optimization algorithm are presented. A discussion of the convergence characteristics of the fully stressed design is also included. Derivations and concepts specific to the ATLAS design theory are shown, while conventional terminology and established methods are identified by references.

Optimum structural design with plate bending elements - A survey

NASA Technical Reports Server (NTRS)

Haftka, R. T.; Prasad, B.

1981-01-01

A survey is presented of recently published papers in the field of optimum structural design of plates, largely with respect to the minimum-weight design of plates subject to such constraints as fundamental frequency maximization. It is shown that, due to the availability of powerful computers, the trend in optimum plate design is away from methods tailored to specific geometry and loads and toward methods that can be easily programmed for any kind of plate, such as finite element methods. A corresponding shift is seen in optimization from variational techniques to numerical optimization algorithms. Among the topics covered are fully stressed design and optimality criteria, mathematical programming, smooth and ribbed designs, design against plastic collapse, buckling constraints, and vibration constraints.

Integrated flight/propulsion control - Subsystem specifications for performance

NASA Technical Reports Server (NTRS)

Neighbors, W. K.; Rock, Stephen M.

1993-01-01

A procedure is presented for calculating multiple subsystem specifications given a number of performance requirements on the integrated system. This procedure applies to problems where the control design must be performed in a partitioned manner. It is based on a structured singular value analysis, and generates specifications as magnitude bounds on subsystem uncertainties. The performance requirements should be provided in the form of bounds on transfer functions of the integrated system. This form allows the expression of model following, command tracking, and disturbance rejection requirements. The procedure is demonstrated on a STOVL aircraft design.

40 CFR 412.46 - New source performance standards (NSPS).

Code of Federal Regulations, 2014 CFR

2014-07-01

... designed open manure storage structure. For those CAFOs where 100 years of local weather data for the CAFO... based upon a site-specific evaluation of the CAFO's open surface manure storage structure. The NPDES... the case of any CAFO using an open surface manure storage structure for which the Director establishes...

40 CFR 412.46 - New source performance standards (NSPS).

Code of Federal Regulations, 2013 CFR

2013-07-01

... designed open manure storage structure. For those CAFOs where 100 years of local weather data for the CAFO... based upon a site-specific evaluation of the CAFO's open surface manure storage structure. The NPDES... the case of any CAFO using an open surface manure storage structure for which the Director establishes...

40 CFR 412.46 - New source performance standards (NSPS).

Code of Federal Regulations, 2012 CFR

2012-07-01

... designed open manure storage structure. For those CAFOs where 100 years of local weather data for the CAFO... based upon a site-specific evaluation of the CAFO's open surface manure storage structure. The NPDES... the case of any CAFO using an open surface manure storage structure for which the Director establishes...

The development of advanced manufacturing systems

NASA Astrophysics Data System (ADS)

Doumeingts, Guy; Vallespir, Bruno; Darricau, Didier; Roboam, Michel

Various methods for the design of advanced manufacturing systems (AMSs) are reviewed. The specifications for AMSs and problems inherent in their development are first discussed. Three models, the Computer Aided Manufacturing-International model, the National Bureau of Standards model, and the GRAI model, are considered in detail. Hierarchical modeling tools such as structured analysis and design techniques, Petri nets, and the Icam definition method are used in the development of integrated manufacturing models. Finally, the GRAI method is demonstrated in the design of specifications for the production management system of the Snecma AMS.

Computational design of protein antigens that interact with the CDR H3 loop of HIV broadly neutralizing antibody 2F5.

PubMed

Azoitei, M L; Ban, Y A; Kalyuzhny, O; Guenaga, J; Schroeter, A; Porter, J; Wyatt, R; Schief, William R

2014-10-01

Rational design of proteins with novel binding specificities and increased affinity is one of the major goals of computational protein design. Epitope-scaffolds are a new class of antigens engineered by transplanting viral epitopes of predefined structure to protein scaffolds, or by building protein scaffolds around such epitopes. Epitope-scaffolds are of interest as vaccine components to attempt to elicit neutralizing antibodies targeting the specified epitope. In this study we developed a new computational protocol, MultiGraft Interface, that transplants epitopes but also designs additional scaffold features outside the epitope to enhance antibody-binding specificity and potentially influence the specificity of elicited antibodies. We employed MultiGraft Interface to engineer novel epitope-scaffolds that display the known epitope of human immunodeficiency virus 1 (HIV-1) neutralizing antibody 2F5 and that also interact with the functionally important CDR H3 antibody loop. MultiGraft Interface generated an epitope-scaffold that bound 2F5 with subnanomolar affinity (K(D) = 400 pM) and that interacted with the antibody CDR H3 loop through computationally designed contacts. Substantial structural modifications were necessary to engineer this antigen, with the 2F5 epitope replacing a helix in the native scaffold and with 15% of the native scaffold sequence being modified in the design stage. This epitope-scaffold represents a successful example of rational protein backbone engineering and protein-protein interface design and could prove useful in the field of HIV vaccine design. MultiGraft Interface can be generally applied to engineer novel binding partners with altered specificity and optimized affinity. © 2014 Wiley Periodicals, Inc.

Mesoscopic structure conditions the emergence of cooperation on social networks

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

Lozano, S.; Arenas, A.; Sanchez, A.

We study the evolutionary Prisoner's Dilemma on two social networks substrates obtained from actual relational data. We find very different cooperation levels on each of them that cannot be easily understood in terms of global statistical properties of both networks. We claim that the result can be understood at the mesoscopic scale, by studying the community structure of the networks. We explain the dependence of the cooperation level on the temptation parameter in terms of the internal structure of the communities and their interconnections. We then test our results on community-structured, specifically designed artificial networks, finding a good agreement withmore » the observations in both real substrates. Our results support the conclusion that studies of evolutionary games on model networks and their interpretation in terms of global properties may not be sufficient to study specific, real social systems. Further, the study allows us to define new quantitative parameters that summarize the mesoscopic structure of any network. In addition, the community perspective may be helpful to interpret the origin and behavior of existing networks as well as to design structures that show resilient cooperative behavior.« less

System among the corticosteroids: specificity and molecular dynamics

PubMed Central

Brookes, Jennifer C.; Galigniana, Mario D.; Harker, Anthony H.; Stoneham, A. Marshall; Vinson, Gavin P.

2012-01-01

Understanding how structural features determine specific biological activities has often proved elusive. With over 161 000 steroid structures described, an algorithm able to predict activity from structural attributes would provide manifest benefits. Molecular simulations of a range of 35 corticosteroids show striking correlations between conformational mobility and biological specificity. Thus steroid ring A is important for glucocorticoid action, and is rigid in the most specific (and potent) examples, such as dexamethasone. By contrast, ring C conformation is important for the mineralocorticoids, and is rigid in aldosterone. Other steroids that are less specific, or have mixed functions, or none at all, are more flexible. One unexpected example is 11-deoxycorticosterone, which the methods predict (and our activity studies confirm) is not only a specific mineralocorticoid, but also has significant glucocorticoid activity. These methods may guide the design of new corticosteroid agonists and antagonists. They will also have application in other examples of ligand–receptor interactions. PMID:21613285

Parametric geometric model and hydrodynamic shape optimization of a flying-wing structure underwater glider

NASA Astrophysics Data System (ADS)

Wang, Zhen-yu; Yu, Jian-cheng; Zhang, Ai-qun; Wang, Ya-xing; Zhao, Wen-tao

2017-12-01

Combining high precision numerical analysis methods with optimization algorithms to make a systematic exploration of a design space has become an important topic in the modern design methods. During the design process of an underwater glider's flying-wing structure, a surrogate model is introduced to decrease the computation time for a high precision analysis. By these means, the contradiction between precision and efficiency is solved effectively. Based on the parametric geometry modeling, mesh generation and computational fluid dynamics analysis, a surrogate model is constructed by adopting the design of experiment (DOE) theory to solve the multi-objects design optimization problem of the underwater glider. The procedure of a surrogate model construction is presented, and the Gaussian kernel function is specifically discussed. The Particle Swarm Optimization (PSO) algorithm is applied to hydrodynamic design optimization. The hydrodynamic performance of the optimized flying-wing structure underwater glider increases by 9.1%.

Design and structure of stapled peptides binding to estrogen receptors.

PubMed

Phillips, Chris; Roberts, Lee R; Schade, Markus; Bazin, Richard; Bent, Andrew; Davies, Nichola L; Moore, Rob; Pannifer, Andrew D; Pickford, Andrew R; Prior, Stephen H; Read, Christopher M; Scott, Andrew; Brown, David G; Xu, Bin; Irving, Stephen L

2011-06-29

Synthetic peptides that specifically bind nuclear hormone receptors offer an alternative approach to small molecules for the modulation of receptor signaling and subsequent gene expression. Here we describe the design of a series of novel stapled peptides that bind the coactivator peptide site of estrogen receptors. Using a number of biophysical techniques, including crystal structure analysis of receptor-stapled peptide complexes, we describe in detail the molecular interactions and demonstrate that all-hydrocarbon staples modulate molecular recognition events. The findings have implications for the design of stapled peptides in general.

A novel method for finding the initial structure parameters of optical systems via a genetic algorithm

NASA Astrophysics Data System (ADS)

Jun, LIU; Huang, Wei; Hongjie, Fan

2016-02-01

A novel method for finding the initial structure parameters of an optical system via the genetic algorithm (GA) is proposed in this research. Usually, optical designers start their designs from the commonly used structures from a patent database; however, it is time consuming to modify the patented structures to meet the specification. A high-performance design result largely depends on the choice of the starting point. Accordingly, it would be highly desirable to be able to calculate the initial structure parameters automatically. In this paper, a method that combines a genetic algorithm and aberration analysis is used to determine an appropriate initial structure of an optical system. We use a three-mirror system as an example to demonstrate the validity and reliability of this method. On-axis and off-axis telecentric three-mirror systems are obtained based on this method.

Hiding the weakness: structural robustness using origami design

NASA Astrophysics Data System (ADS)

Liu, Bin; Santangelo, Christian; Cohen, Itai

2015-03-01

A non-deformable structure is typically associated with infinitely stiff materials that resist distortion. In this work, we designed a structure with a region that will not deform even though it is made of arbitrarily compliant materials. More specifically, we show that a foldable sheet with a circular hole in the middle can be deformed externally with the internal geometry of the hole unaffected. Instead of strengthening the local stiffness, we fine tune the crease patterns so that all the soft modes that can potentially deform the internal geometry are not accessible through strain on the external boundary. The inner structure is thus protected by the topological mechanics, based on the detailed geometry of how the vertices in the foldable sheet are connected. In this way, we isolate the structural robustness from the mechanical properties of the materials, which introduces an extra degree of freedom for structural design.

Research requirements to reduce empty weight of helicopters by use of advanced materials

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

Hoffstedt, D.J.

1976-12-01

Utilization of the new, lightweight, high-strength, aerospace structural-composite (filament/matrix) materials, when specifically designed into a new aircraft, promises reductions in structural empty weight of 12% at recurring costs competetive with metals. A program of basic and applied research and demonstration is identified with the objective of advancing the state of the art to the point where civil helicopters are confidently designed, produced, certified, and marketed by 1985. A structural empty-weight reduction of 12% was shown to significantly reduce energy consumption in modern high-performance helicopters.

Measurements of weak interactions between truncated substrates and a hammerhead ribozyme by competitive kinetic analyses: implications for the design of new and efficient ribozymes with high sequence specificity

PubMed Central

Kasai, Yasuhiro; Shizuku, Hideki; Takagi, Yasuomi; Warashina, Masaki; Taira, Kazunari

2002-01-01

Exploitation of ribozymes in a practical setting requires high catalytic activity and strong specificity. The hammerhead ribozyme R32 has considerable potential in this regard since it has very high catalytic activity. In this study, we have examined how R32 recognizes and cleaves a specific substrate, focusing on the mechanism behind the specificity. Comparing rates of cleavage of a substrate in a mixture that included the correct substrate and various substrates with point mutations, we found that R32 cleaved the correct substrate specifically and at a high rate. To clarify the source of this strong specificity, we quantified the weak interactions between R32 and various truncated substrates, using truncated substrates as competitive inhibitors since they were not readily cleaved during kinetic measurements of cleavage of the correct substrate, S11. We found that the strong specificity of the cleavage reaction was due to a closed form of R32 with a hairpin structure. The self-complementary structure within R32 enabled the ribozyme to discriminate between the correct substrate and a mismatched substrate. Since this hairpin motif did not increase the Km (it did not inhibit the binding interaction) or decrease the kcat (it did not decrease the cleavage rate), this kind of hairpin structure might be useful for the design of new ribozymes with strong specificity and high activity. PMID:12034825

Nanoparticle Superlattice Engineering with DNA

NASA Astrophysics Data System (ADS)

Macfarlane, Robert J.; Lee, Byeongdu; Jones, Matthew R.; Harris, Nadine; Schatz, George C.; Mirkin, Chad A.

2011-10-01

A current limitation in nanoparticle superlattice engineering is that the identities of the particles being assembled often determine the structures that can be synthesized. Therefore, specific crystallographic symmetries or lattice parameters can only be achieved using specific nanoparticles as building blocks (and vice versa). We present six design rules that can be used to deliberately prepare nine distinct colloidal crystal structures, with control over lattice parameters on the 25- to 150-nanometer length scale. These design rules outline a strategy to independently adjust each of the relevant crystallographic parameters, including particle size (5 to 60 nanometers), periodicity, and interparticle distance. As such, this work represents an advance in synthesizing tailorable macroscale architectures comprising nanoscale materials in a predictable fashion.

Spatial Data Transfer Standard (SDTS), part 1 : logical specifications

DOT National Transportation Integrated Search

1997-11-20

This document contains a specification of the Spatial Data Transfer Standard (SDTS), that will serve as a national spatial data transfer mechanism for the United States. As such it is designed to transfer a wide variety of data structures that are us...

Seismic Design Considerations : Volume I, Technical Approaches and Results; Volume II, Appendices II-VIII

DOT National Transportation Integrated Search

2012-03-01

NJDOT has adopted AASHTO Guide Specifications for LRFD Seismic Bridge Design approved by the Highway : Subcommittee on Bridges and Structures in 2007. The main objective of research presented in this report has : been to resolve following issue...

Development of Secondary Route Bridge Design Plan Guides

DOT National Transportation Integrated Search

2018-03-03

The objective of this study is to develop a set of bridge plan guides for low-volume traffic roads. The purpose of the plans is to facilitate construction of new structures suitable for local agencies. The designs are to specifically address common l...

Program for establishing long time flight service performance of composite materials in the central wing structure of C-130 aircraft. Phase 2: Detailed design

NASA Technical Reports Server (NTRS)

Harvill, W. E.; Duhig, J. J.; Spencer, B. R.

1973-01-01

The design, fabrication, and evaluation of boron-epoxy reinforced C-130 center wing boxes are discussed. Design drawings, static strength, fatigue endurance, flutter, and weight analyses required for the wing box fabrication are presented. Additional component testing to verify the design for panel buckling and to evaluate specific local design areas are reported.

Porous silicon structures with high surface area/specific pore size

DOEpatents

Northrup, M.A.; Yu, C.M.; Raley, N.F.

1999-03-16

Fabrication and use of porous silicon structures to increase surface area of heated reaction chambers, electrophoresis devices, and thermopneumatic sensor-actuators, chemical preconcentrates, and filtering or control flow devices. In particular, such high surface area or specific pore size porous silicon structures will be useful in significantly augmenting the adsorption, vaporization, desorption, condensation and flow of liquids and gases in applications that use such processes on a miniature scale. Examples that will benefit from a high surface area, porous silicon structure include sample preconcentrators that are designed to adsorb and subsequently desorb specific chemical species from a sample background; chemical reaction chambers with enhanced surface reaction rates; and sensor-actuator chamber devices with increased pressure for thermopneumatic actuation of integrated membranes. Examples that benefit from specific pore sized porous silicon are chemical/biological filters and thermally-activated flow devices with active or adjacent surfaces such as electrodes or heaters. 9 figs.

Porous silicon structures with high surface area/specific pore size

DOEpatents

Northrup, M. Allen; Yu, Conrad M.; Raley, Norman F.

1999-01-01

Fabrication and use of porous silicon structures to increase surface area of heated reaction chambers, electrophoresis devices, and thermopneumatic sensor-actuators, chemical preconcentrates, and filtering or control flow devices. In particular, such high surface area or specific pore size porous silicon structures will be useful in significantly augmenting the adsorption, vaporization, desorption, condensation and flow of liquids and gasses in applications that use such processes on a miniature scale. Examples that will benefit from a high surface area, porous silicon structure include sample preconcentrators that are designed to adsorb and subsequently desorb specific chemical species from a sample background; chemical reaction chambers with enhanced surface reaction rates; and sensor-actuator chamber devices with increased pressure for thermopneumatic actuation of integrated membranes. Examples that benefit from specific pore sized porous silicon are chemical/biological filters and thermally-activated flow devices with active or adjacent surfaces such as electrodes or heaters.

SMS crew station (C and D panels and forward structures). CEI part 1: Detail specification, type 1 data

NASA Technical Reports Server (NTRS)

1976-01-01

Established are the requirements for performance, design, test and qualification of one type of equipment identified as SMS C&D panels and forward structures. This CEI is used to provide all hardware and wiring necessary for the C&D panels to be properly interfaced with the computer complex/signal conversion equipment (SCE), crew station, and software requirements as defined in other CEI specifications.

The Effect of Differentially Designed Fusion Proteins to Elicit Efficient Anti-human Thyroid Stimulating Hormone Immune Responses.

PubMed

Mard-Soltani, Maysam; Rasaee, Mohamad Javad; Khalili, Saeed; Sheikhi, Abdol-Karim; Hedayati, Mehdi; Ghaderi-Zefrehi, Hossein; Alasvand, Milad

2018-04-01

The production of human thyroid stimulating hormone (hTSH) immunoassays requires specific antibodies against hTSH which is a cumbersome process. Therefore, producing specific polyclonal antibodies against engineered recombinant fusion hTSH antigens would be of great significance. The best immunogenic region of the hTSH was selected based on in silico analyses and equipped with two different fusions. Standard methods were used for protein expression, purification, verification, structural evaluation, and immunizations of the white New Zealand rabbits. Ultimately, immunized serums were used for antibody titration, purification and characterization (specificity, sensitivity and cross reactivity). The desired antigens were successfully designed, sub-cloned, expressed, confirmed and used for in vivo immunization. Structural analyses indicated that only the bigger antigen has showed changed 2 dimensional (2D) and 3D structural properties in comparison to the smaller antigen. The raised polyclonal antibodies were capable of specific and sensitive hTSH detection, while the cross reactivity with the other members of the glycoprotein hormone family was minimum and negligible. The fusion which was solely composed of the tetanus toxin epitopes led to better protein folding and was capable of immunizing the host animals resulting into high titer antibody. Therefore, the minimal fusion sequences seem to be more effective in eliciting specific antibody responses.

49 CFR 41.119 - DOT regulated buildings.

Code of Federal Regulations, 2010 CFR

2010-10-01

...) Each DOT Operating Administration with responsibility for regulating the structural safety of buildings... section pertains to all new building projects for which development of detailed plans and specifications... regulating the structural safety must comply with the seismic design and construction standards in this part...

Integration of Design, Thermal, Structural, and Optical Analysis, Including Thermal Animation

NASA Technical Reports Server (NTRS)

Amundsen, Ruth M.

1993-01-01

In many industries there has recently been a concerted movement toward 'quality management' and the issue of how to accomplish work more efficiently. Part of this effort is focused on concurrent engineering; the idea of integrating the design and analysis processes so that they are not separate, sequential processes (often involving design rework due to analytical findings) but instead form an integrated system with smooth transfers of information. Presented herein are several specific examples of concurrent engineering methods being carried out at Langley Research Center (LaRC): integration of thermal, structural and optical analyses to predict changes in optical performance based on thermal and structural effects; integration of the CAD design process with thermal and structural analyses; and integration of analysis and presentation by animating the thermal response of a system as an active color map -- a highly effective visual indication of heat flow.

Validation of a SysML based design for wireless sensor networks

NASA Astrophysics Data System (ADS)

Berrachedi, Amel; Rahim, Messaoud; Ioualalen, Malika; Hammad, Ahmed

2017-07-01

When developing complex systems, the requirement for the verification of the systems' design is one of the main challenges. Wireless Sensor Networks (WSNs) are examples of such systems. We address the problem of how WSNs must be designed to fulfil the system requirements. Using the SysML Language, we propose a Model Based System Engineering (MBSE) specification and verification methodology for designing WSNs. This methodology uses SysML to describe the WSNs requirements, structure and behaviour. Then, it translates the SysML elements to an analytic model, specifically, to a Deterministic Stochastic Petri Net. The proposed approach allows to design WSNs and study their behaviors and their energy performances.

Design specifications for NALDA (Naval Aviation Logistics Data Analysis) CAI (computer aided instruction): Phase 2, Interim report

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

Twitty, A.F.; Handler, B.H.; Duncan, L.D.

Data Systems Engineering Organization (DSEO) personnel are developing a prototype computer aided instruction (CAI) system for the Naval Aviation Logistics Data Analysis (NALDA) system. The objective of this project is to provide a prototype for implementing CAI as an enhancement to existing NALDA training. The CAI prototype project is being performed in phases. The task undertaken in Phase I was to analyze the problem and the alternative solutions and to develop a set of recommendations on how best to proceed. In Phase II a structured design and specification document was completed that will provide the basis for development and implementationmore » of the desired CAI system. Phase III will consist of designing, developing, and testing a user interface which will extend the features of the Phase II prototype. The design of the CAI prototype has followed a rigorous structured analysis based on Yourdon/DeMarco methodology and Information Engineering tools. This document includes data flow diagrams, a data dictionary, process specifications, an entity-relationship diagram, a curriculum description, special function key definitions, and a set of standards developed for the NALDA CAI Prototype.« less

Decoupling local mechanics from large-scale structure in modular metamaterials

NASA Astrophysics Data System (ADS)

Yang, Nan; Silverberg, Jesse L.

2017-04-01

A defining feature of mechanical metamaterials is that their properties are determined by the organization of internal structure instead of the raw fabrication materials. This shift of attention to engineering internal degrees of freedom has coaxed relatively simple materials into exhibiting a wide range of remarkable mechanical properties. For practical applications to be realized, however, this nascent understanding of metamaterial design must be translated into a capacity for engineering large-scale structures with prescribed mechanical functionality. Thus, the challenge is to systematically map desired functionality of large-scale structures backward into a design scheme while using finite parameter domains. Such “inverse design” is often complicated by the deep coupling between large-scale structure and local mechanical function, which limits the available design space. Here, we introduce a design strategy for constructing 1D, 2D, and 3D mechanical metamaterials inspired by modular origami and kirigami. Our approach is to assemble a number of modules into a voxelized large-scale structure, where the module’s design has a greater number of mechanical design parameters than the number of constraints imposed by bulk assembly. This inequality allows each voxel in the bulk structure to be uniquely assigned mechanical properties independent from its ability to connect and deform with its neighbors. In studying specific examples of large-scale metamaterial structures we show that a decoupling of global structure from local mechanical function allows for a variety of mechanically and topologically complex designs.

Design, Synthesis, and Evaluation of Novel p-(methylthio)styryl Substituted Quindoline Derivatives as Neuroblastoma RAS (NRAS) Repressors via Specific Stabilizing the RNA G-Quadruplex.

PubMed

Peng, Wang; Sun, Zhi-Yin; Zhang, Qi; Cheng, Sui-Qi; Wang, Shi-Ke; Wang, Xiao-Na; Kuang, Guo-Tao; Su, Xiao-Xuan; Tan, Jia-Heng; Huang, Zhi-Shu; Ou, Tian-Miao

2018-05-25

The human proto-oncogene neuroblastoma RAS (NRAS) contains a guanine-rich sequence in the 5'-untranslated regions (5'-UTR) of the mRNA that could form an RNA G-quadruplex structure. This structure acts as a repressor for NRAS translation and could be a potential target for anti-cancer drugs. Our previous studies found an effective scaffold, the quindoline scaffold, for binding and stabilizing the DNA G-quadruplex structures. Here, basing on the previous studies and reported RNA-specific probes, a series of novel p-(methylthio)styryl substituted quindoline (MSQ) derivatives were designed, synthesized and evaluated as NRAS RNA G-quadruplex ligands. Panels of experiments turned out that the introduction of p-(methylthio)styryl side chain could enhance the specific binding to the NRAS RNA G-quadruplex. One of the hits, 4a-10, showed strong stabilizing activity on the G-quadruplex, and subsequently repressed NRAS's translation and inhibited tumor cells proliferation. Our finding provided a novel strategy to discover novel NRAS repressors by specifically binding to the RNA G-quadruplex in the 5'-UTR of mRNA.

Zeolites: Can they be synthesized by design

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

Davis, M.E.

1994-09-01

Zeolites and zeolite-like molecular sieves are crystalline oxides that have high surface-to-volume ratios and are able to recognize, discriminate, and organize molecules with differences of < 1 [angstrom]. The close connection between the atomic structure and macroscopic properties of these materials has led to uses in molecular recognition. For example, zeolites and zeolite-like molecular sieves can reveal marvelous molecular recognition specificity and sensitivity that can be applied to catalysis, separations technology, and chemical sensing. Additionally, they can serve as hosts to organize guest atoms and molecules that endow composite materials with optoelectric and electrochemical properties. Because of the high levelmore » of structural control necessary to create high-performance materials with zeolites or zeolite-like molecular sieves, the design and synthesis of these solids with specific architectures and properties are highly desired. Although this lofty goal is still elusive, advances have been made to allow the serious consideration of designing molecular sieves. Here, the author covers two aspects of this ongoing effort. First, he discusses the feasibility of designing pore architectures through the use of organic structure-directing agents. Second, he explores the possibility of creating zeolites through ''Lego chemistry.''« less

Coupling Adaptation Tipping Points and Engineering Options: New Insights for Resilient Water Infrastructure Replacement Planning

NASA Astrophysics Data System (ADS)

Smet, K.; de Neufville, R.; van der Vlist, M.

2017-12-01

This work presents an innovative approach for replacement planning for aging water infrastructure given uncertain future conditions. We draw upon two existing methodologies to develop an integrated long-term replacement planning framework. We first expand the concept of Adaptation Tipping Points to generate long-term planning timelines that incorporate drivers of investment related to both internal structural processes as well as changes in external operating conditions. Then, we use Engineering Options to explore different actions taken at key moments in this timeline. Contrasting to the traditionally more static approach to infrastructure design, designing the next generation of infrastructure so it can be changed incrementally is a promising method to safeguard current investments given future uncertainty. This up-front inclusion of structural options in the system actively facilitates future adaptation, transforming uncertainty management in infrastructure planning from reactive to more proactive. A two-part model underpins this approach. A simulation model generates diverse future conditions, allowing development of timelines of intervention moments in the structure's life. This feeds into an economic model, evaluating the lifetime performance of different replacement strategies, making explicit the value of different designs and their flexibility. A proof of concept study demonstrates this approach for a pumping station. The strategic planning timelines for this structure demonstrate that moments when capital interventions become necessary due to reduced functionality from structural degradation or changed operating conditions are widely spread over the structure's life. The disparate timing of these necessary interventions supports an incremental, adaptive mindset when considering end-of-life and replacement decisions. The analysis then explores different replacement decisions, varying the size and specific options included in the proposed new structure. Results show that incremental adaptive designs and incorporating options can improve economic performance, as compared to traditional, "build it once & build it big" designs. The benefit from incorporating flexibility varies with structural functionality, future conditions and the specific options examined.

Capillary Structures for Exploration Life Support (Capillary Structures)

NASA Image and Video Library

2017-07-10

iss052e013146 (July 10, 2017) --- Astronaut Jack Fischer is photographed during setup of hardware for the Capillary Structures for Exploration Life Support (Capillary Structures) two sorbent demonstrations. The Capillary Structures for Exploration Life Support (Capillary Structures) investigation studies a new method using structures of specific shapes to manage fluid and gas mixtures. The investigation studies water recycling and carbon dioxide removal, benefiting future efforts to design lightweight, more reliable life support systems for future space missions.

Recent Methods for Purification and Structure Determination of Oligonucleotides.

PubMed

Zhang, Qiulong; Lv, Huanhuan; Wang, Lili; Chen, Man; Li, Fangfei; Liang, Chao; Yu, Yuanyuan; Jiang, Feng; Lu, Aiping; Zhang, Ge

2016-12-18

Aptamers are single-stranded DNA or RNA oligonucleotides that can interact with target molecules through specific three-dimensional structures. The excellent features, such as high specificity and affinity for target proteins, small size, chemical stability, low immunogenicity, facile chemical synthesis, versatility in structural design and engineering, and accessible for site-specific modifications with functional moieties, make aptamers attractive molecules in the fields of clinical diagnostics and biopharmaceutical therapeutics. However, difficulties in purification and structural identification of aptamers remain a major impediment to their broad clinical application. In this mini-review, we present the recently attractive developments regarding the purification and identification of aptamers. We also discuss the advantages, limitations, and prospects for the major methods applied in purifying and identifying aptamers, which could facilitate the application of aptamers.

Computational design of an enzyme catalyst for a stereoselective bimolecular Diels-Alder reaction

PubMed Central

Siegel, Justin B.; Zanghellini, Alexandre; Lovick, Helena M.; Kiss, Gert; Lambert, Abigail R.; St.Clair, Jennifer L.; Gallaher, Jasmine L.; Hilvert, Donald; Gelb, Michael H.; Stoddard, Barry L.; Houk, Kendall N.; Michael, Forrest E.; Baker, David

2011-01-01

The Diels-Alder reaction is a cornerstone in organic synthesis, forming two carbon-carbon bonds and up to four new stereogenic centers in one step. No naturally occurring enzymes have been shown to catalyze bimolecular Diels-Alder reactions. We describe the de novo computational design and experimental characterization of enzymes catalyzing a bimolecular Diels-Alder reaction with high stereoselectivity and substrate specificity. X-ray crystallography confirms that the structure matches the design for the most active of the enzymes, and binding site substitutions reprogram the substrate specificity. Designed stereoselective catalysts for carbon-carbon bond forming reactions should be broadly useful in synthetic chemistry. PMID:20647463

Computational design of an enzyme catalyst for a stereoselective bimolecular Diels-Alder reaction.

PubMed

Siegel, Justin B; Zanghellini, Alexandre; Lovick, Helena M; Kiss, Gert; Lambert, Abigail R; St Clair, Jennifer L; Gallaher, Jasmine L; Hilvert, Donald; Gelb, Michael H; Stoddard, Barry L; Houk, Kendall N; Michael, Forrest E; Baker, David

2010-07-16

The Diels-Alder reaction is a cornerstone in organic synthesis, forming two carbon-carbon bonds and up to four new stereogenic centers in one step. No naturally occurring enzymes have been shown to catalyze bimolecular Diels-Alder reactions. We describe the de novo computational design and experimental characterization of enzymes catalyzing a bimolecular Diels-Alder reaction with high stereoselectivity and substrate specificity. X-ray crystallography confirms that the structure matches the design for the most active of the enzymes, and binding site substitutions reprogram the substrate specificity. Designed stereoselective catalysts for carbon-carbon bond-forming reactions should be broadly useful in synthetic chemistry.

Nonlinear Shaping Architecture Designed with Using Evolutionary Structural Optimization Tools

NASA Astrophysics Data System (ADS)

Januszkiewicz, Krystyna; Banachowicz, Marta

2017-10-01

The paper explores the possibilities of using Structural Optimization Tools (ESO) digital tools in an integrated structural and architectural design in response to the current needs geared towards sustainability, combining ecological and economic efficiency. The first part of the paper defines the Evolutionary Structural Optimization tools, which were developed specifically for engineering purposes using finite element analysis as a framework. The development of ESO has led to several incarnations, which are all briefly discussed (Additive ESO, Bi-directional ESO, Extended ESO). The second part presents result of using these tools in structural and architectural design. Actual building projects which involve optimization as a part of the original design process will be presented (Crematorium in Kakamigahara Gifu, Japan, 2006 SANAA“s Learning Centre, EPFL in Lausanne, Switzerland 2008 among others). The conclusion emphasizes that the structural engineering and architectural design mean directing attention to the solutions which are used by Nature, designing works optimally shaped and forming their own environments. Architectural forms never constitute the optimum shape derived through a form-finding process driven only by structural optimization, but rather embody and integrate a multitude of parameters. It might be assumed that there is a similarity between these processes in nature and the presented design methods. Contemporary digital methods make the simulation of such processes possible, and thus enable us to refer back to the empirical methods of previous generations.

Crashworthiness analysis on alternative square honeycomb structure under axial loading

NASA Astrophysics Data System (ADS)

Li, Meng; Deng, Zongquan; Guo, Hongwei; Liu, Rongqiang; Ding, Beichen

2013-07-01

Hexagonal metal honeycomb is widely used in energy absorption field for its special construction. However, many other metal honeycomb structures also show good energy absorption characteristics. Currently, most of the researches focus on hexagonal honeycomb, while few are performed into different honeycomb structures. Therefore, a new alternative square honeycomb is developed to expand the non-hexagonal metal honeycomb applications in the energy absorption fields with the aim of designing low mass and low volume energy absorbers. The finite element model of alternative square honeycomb is built to analyze its specific energy absorption property. As the diversity of honeycomb structure, the parameterized metal honeycomb finite element analysis program is conducted based on PCL language. That program can automatically create finite element model. Numerical results show that with the same foil thickness and cell length of metal honeycomb, the alternative square has better specific energy absorption than hexagonal honeycomb. Using response surface method, the mathematical formulas of honeycomb crashworthiness properties are obtained and optimization is done to get the maximum specific energy absorption property honeycomb. Optimal results demonstrate that to absorb same energy, alternative square honeycomb can save 10% volume of buffer structure than hexagonal honeycomb can do. This research is significant in providing technical support in the extended application of different honeycomb used as crashworthiness structures, and is absolutely essential in low volume and low mass energy absorber design.

Design of Multiple Bolted Connections for Laminated Veneer Lumber

Treesearch

Borjen Yeh; Douglas Rammer; Jeff Linville

2014-01-01

The design of multiple bolted connections in accordance with Appendix E of the National Design Specification for Wood Construction (NDS) has incorporated provisions for evaluating localized member failure modes of row and group tear-out when the connections are closely spaced. Originally based on structural glued laminated timber (glulam) members made with all L1...

Preliminary study for a numerical aerodynamic simulation facility. Phase 1: Extension

NASA Technical Reports Server (NTRS)

Lincoln, N. R.

1978-01-01

Functional requirements and preliminary design data were identified for use in the design of all system components and in the construction of a facility to perform aerodynamic simulation for airframe design. A skeleton structure of specifications for the flow model processor and monitor, the operating system, and the language and its compiler is presented.

Supporting Faculty in the Design and Structuring of Web-Based Courses.

ERIC Educational Resources Information Center

Freeman, H.; Ryan, S.; Boys, J.

This paper reports on the development and extension of a concept mapping tool into a complete online course design support framework for academics: CEDOT (Course Elicitation, Development and Output Tool). The tool provides a course design framework that faculty work through in an order of their choosing. It gives context specific help and advice…

Design Report for the Synchronized Position, Velocity, and Time Code Generator

DTIC Science & Technology

2015-08-01

Stream Specification 4 2.3 Data Packet Format Specification 4 2.3.1 Individual Message Definition 5 3. MATLAB Parsing Software 6 4. Conclusions and...packet format structure ..................................................................4 Table 2 PPS time message definition ...5 Table 3 Position message definition ...................................................................5

SPS structures and control: A perspective

NASA Technical Reports Server (NTRS)

Ried, R. C.

1980-01-01

The characteristics and design requirements for the structure and control systems for a solar power satellite were evaluated. A simplistic, indicative analysis on a representative configuration was developed. Representative configuration masses and dimensions are given in convenient approximate magnitudes. The significance of structure control interaction and the significance of stiffness to the minimization of dynamic energy was demonstrated. It was found that the thermal environment for the SPS was dominated by solar radiation and waste heat rejection by the antenna. A more in-depth assessment of the control system design and associated system performance is still needed, specifically the inter-relatonships between control sensors, actuators, and structural response.

Explicit parametric solutions of lattice structures with proper generalized decomposition (PGD) - Applications to the design of 3D-printed architectured materials

NASA Astrophysics Data System (ADS)

Sibileau, Alberto; Auricchio, Ferdinando; Morganti, Simone; Díez, Pedro

2018-01-01

Architectured materials (or metamaterials) are constituted by a unit-cell with a complex structural design repeated periodically forming a bulk material with emergent mechanical properties. One may obtain specific macro-scale (or bulk) properties in the resulting architectured material by properly designing the unit-cell. Typically, this is stated as an optimal design problem in which the parameters describing the shape and mechanical properties of the unit-cell are selected in order to produce the desired bulk characteristics. This is especially pertinent due to the ease manufacturing of these complex structures with 3D printers. The proper generalized decomposition provides explicit parametic solutions of parametric PDEs. Here, the same ideas are used to obtain parametric solutions of the algebraic equations arising from lattice structural models. Once the explicit parametric solution is available, the optimal design problem is a simple post-process. The same strategy is applied in the numerical illustrations, first to a unit-cell (and then homogenized with periodicity conditions), and in a second phase to the complete structure of a lattice material specimen.

Packaging of electronic modules

NASA Technical Reports Server (NTRS)

Katzin, L.

1966-01-01

Study of design approaches that are taken toward optimizing the packaging of electronic modules with respect to size, shape, component orientation, interconnections, and structural support. The study does not present a solution to specific packaging problems, but rather the factors to be considered to achieve optimum packaging designs.

Analysis of Virginia-specific traffic data inputs for use with the mechanistic-empirical pavement design guide.

DOT National Transportation Integrated Search

2010-02-01

This study developed traffic inputs for use with the Guide for the Mechanistic-Empirical Design of New & Rehabilitated Pavement Structures (MEPDG) in Virginia and sought to determine if the predicted distresses showed differences between site-specifi...

The impact of domain knowledge on structured data collection and templated note design.

PubMed

Windle, T; McClay, J C; Windle, J R

2013-01-01

The objective of this case report is to evaluate the importance of specialized domain knowledge when designing and using structured templated notes in a clinical environment. To analyze the impact of specialization on structured note generation we compared notes generated for three scenarios: 1) We compared the templated history of present illness (HPI) for patients presenting with a dermatology concern to the dermatologist versus the emergency department. 2) We compared the evaluation of chest pain by ED physicians versus cardiologists. 3) Finally, we compared the data elements asked for in the evaluation of the gastrointestinal system between cardiologists and the liver transplant service (LTS). We used the SNOMED CT representation via BioPortal to evaluate specificity and grouping between data elements and specialized physician groups. We found few similarities in structured data elements designed by and for the specific physician groups. The distinctness represented both differences in granularity as well as fundamental differences in data elements requested. When compared to ED physicians, dermatologists had different and more granular elements while cardiologists requested much more granular data. Comparing cardiologists and LTS, there were differences in the data elements requested. This case study supports the importance of domain knowledge in EHR design and implementation. That different specialities should want and use different information is well supported by cognitive science literature. Despite this, it is rare for domain knowledge to be considered in EHR implementation. Physicians with correct domain knowledge should be involved in the design process of templated notes.

Structural design of graphene for use in electrochemical energy storage devices.

PubMed

Chen, Kunfeng; Song, Shuyan; Liu, Fei; Xue, Dongfeng

2015-10-07

There are many practical challenges in the use of graphene materials as active components in electrochemical energy storage devices. Graphene has a much lower capacitance than the theoretical capacitance of 550 F g(-1) for supercapacitors and 744 mA h g(-1) for lithium ion batteries. The macroporous nature of graphene limits its volumetric energy density and the low packing density of graphene-based electrodes prevents its use in commercial applications. Increases in the capacity, energy density and power density of electroactive graphene materials are strongly dependent on their microstructural properties, such as the number of defects, stacking, the use of composite materials, conductivity, the specific surface area and the packing density. The structural design of graphene electrode materials is achieved via six main strategies: the design of non-stacking and three-dimensional graphene; the synthesis of highly packed graphene; the production of graphene with a high specific surface area and high conductivity; the control of defects; functionalization with O, N, B or P heteroatoms; and the formation of graphene composites. These methodologies of structural design are needed for fast electrical charge storage/transfer and the transport of electrolyte ions (Li(+), H(+), K(+), Na(+)) in graphene electrodes. We critically review state-of-the-art progress in the optimization of the electrochemical performance of graphene-based electrode materials. The structure of graphene needs to be designed to develop novel electrochemical energy storage devices that approach the theoretical charge limit of graphene and to deliver electrical energy rapidly and efficiently.

Tubular space truss structure for SKITTER 2 robot

NASA Technical Reports Server (NTRS)

Beecham, Richard; Dejulio, Linda; Delorme, Paul; Eck, Eric; Levy, Avi; Lowery, Joel; Radack, Joe; Sheffield, Randy; Stevens, Scott

1988-01-01

The Skitter 2 is a three legged transport vehicle designed to demonstrate the principle of a tripod walker in a multitude of environments. The tubular truss model of Skitter 2 is a proof of principal design. The model will replicate the operational capabilities of Skitter 2 including its ability to self-right itself. The project's focus was on the use of light weight tubular members in the final structural design. A strong design for the body was required as it will undergo the most intense loading. Triangular geometry was used extensively in the body, providing the required structural integrity and eliminating the need for cumbersome shear panels. Both the basic femur and tibia designs also relied on the strong geometry of the triangle. An intense literature search aided in the development of the most suitable weld techniques, joints, linkages, and materials required for a durable design. The hinge design features the use of spherical rod end bearings. In order to obtain a greater range of mobility in the tibia, a four-bar linkage was designed which attaches both to the femur and the tibia. All component designs, specifically the body, femur, and the tibia were optimized using the software package IDEAS 3.8A Supertab. The package provided essential deformation and stress analysis information on each component's design. The final structure incurred only a 0.0544 inch deflection in a maximum (worst case) loading situation. The highest stress experienced by any AL6061-T6 tubular member was 1920 psi. The structural integrity of the final design facilitated the use of Aluminum 6061-T6 tubing. The tubular truss structure of Skitter 2 is an effective and highly durable design. All facets of the design are structurally sound and cost effective.

Potential of agricultural fungicides for antifungal drug discovery.

PubMed

Jampilek, Josef

2016-01-01

While it is true that only a small fraction of fungal species are responsible for human mycoses, the increasing prevalence of fungal diseases has highlighted an urgent need to develop new antifungal drugs, especially for systemic administration. This contribution focuses on the similarities between agricultural fungicides and drugs. Inorganic, organometallic and organic compounds can be found amongst agricultural fungicides. Furthermore, fungicides are designed and developed in a similar fashion to drugs based on similar rules and guidelines, with fungicides also having to meet similar criteria of lead-likeness and/or drug-likeness. Modern approved specific-target fungicides are well-characterized entities with a proposed structure-activity relationships hypothesis and a defined mode of action. Extensive toxicological evaluation, including mammalian toxicology assays, is performed during the whole discovery and development process. Thus modern agrochemical research (design of modern agrochemicals) comes close to drug design, discovery and development. Therefore, modern specific-target fungicides represent excellent lead-like structures/models for novel drug design and development.

The Systemic-Structural Theory of Activity: Applications to the Study of Human Work

ERIC Educational Resources Information Center

Bedny, Gregory Z.; Harris, Steven Robert

2005-01-01

This article offers an introduction to the central concepts and principles of the Systemic-Structural Theory of Activity (SSTA), an activity-theoretical approach specifically tailored to the analysis and design of human work. In activity theory, cognition is understood both as a process and as a structured system of actions. Building on the…

AFM Imaging of Hybridization Chain Reaction Mediated Signal Transmission between Two DNA Origami Structures.

PubMed

Helmig, Sarah; Gothelf, Kurt Vesterager

2017-10-23

Signal transfer is central to the controlled exchange of information in biology and advanced technologies. Therefore, the development of reliable, long-range signal transfer systems for artificial nanoscale assemblies is of great scientific interest. We have designed such a system for the signal transfer between two connected DNA nanostructures, using the hybridization chain reaction (HCR). Two sets of metastable DNA hairpins, one of which is immobilized at specific points along tracks on DNA origami structures, are polymerized to form a continuous DNA duplex, which is visible using atomic force microscopy (AFM). Upon addition of a designed initiator, the initiation signal is efficiently transferred more than 200 nm from a specific location on one origami structure to an end point on another origami structure. The system shows no significant loss of signal when crossing from one nanostructure to another and, therefore, has the potential to be applied to larger multi-component DNA assemblies. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Selected issues of the universal communication environment implementation for CII standard

NASA Astrophysics Data System (ADS)

Zagoździńska, Agnieszka; Poźniak, Krzysztof T.; Drabik, Paweł K.

2011-10-01

In the contemporary FPGA market there is the wide assortment of structures, integrated development environments, and boards of different producers. The variety allows to fit resources to requirements of the individual designer. There is the need of standardization of the projects to make it useful in research laboratories equipped with different producers tools. Proposed solution is CII standardization of VHDL components. This paper contains specification of the universal communication environment for CII standard. The link can be used in different FPGA structures. Implementation of the link enables object oriented VHDL programming with the use of CII standardization. The whole environment contains FPGA environment and PC software. The paper contains description of the selected issues of FPGA environment. There is description of some specific solutions that enables environment usage in structures of different producers. The flexibility of different size data transmissions with the use of CII is presented. The specified tool gives the opportunity to use FPGA structures variety fully and design faster and more effectively.

The specificity of cortical region KO to depth structure.

PubMed

Tyler, Christopher W; Likova, Lora T; Kontsevich, Leonid L; Wade, Alex R

2006-03-01

Functional MRI studies have identified a cortical region designated as KO between retinotopic areas V3A/B and motion area V5 in human cortex as particularly responsive to motion-defined or kinetic borders. To determine the response of the KO region to more general aspects of structure, we used stereoscopic depth borders and disparate planes with no borders, together with three stimulus types that evoked no depth percept: luminance borders, line contours and illusory phase borders. Responses to these stimuli in the KO region were compared with the responses in retinotopically defined areas that have been variously associated with disparity processing in neurophysiological and fMRI studies. The strongest responses in the KO region were to stimuli evoking perceived depth structure from either disparity or motion cues, but it showed negligible responses either to luminance-based contour stimuli or to edgeless disparity stimuli. We conclude that the region designated as KO is best regarded as a primary center for the generic representation of depth structure rather than any kind of contour specificity.

Computational design of a red fluorophore ligase for site-specific protein labeling in living cells

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

Liu, Daniel S.; Nivon, Lucas G.; Richter, Florian

In this study, chemical fluorophores offer tremendous size and photophysical advantages over fluorescent proteins but are much more challenging to target to specific cellular proteins. Here, we used Rosetta-based computation to design a fluorophore ligase that accepts the red dye resorufin, starting from Escherichia coli lipoic acid ligase. X-ray crystallography showed that the design closely matched the experimental structure. Resorufin ligase catalyzed the site-specific and covalent attachment of resorufin to various cellular proteins genetically fused to a 13-aa recognition peptide in multiple mammalian cell lines and in primary cultured neurons. We used resorufin ligase to perform superresolution imaging of themore » intermediate filament protein vimentin by stimulated emission depletion and electron microscopies. This work illustrates the power of Rosetta for major redesign of enzyme specificity and introduces a tool for minimally invasive, highly specific imaging of cellular proteins by both conventional and superresolution microscopies.« less

Computational design of a red fluorophore ligase for site-specific protein labeling in living cells

DOE PAGES

Liu, Daniel S.; Nivon, Lucas G.; Richter, Florian; ...

2014-10-13

In this study, chemical fluorophores offer tremendous size and photophysical advantages over fluorescent proteins but are much more challenging to target to specific cellular proteins. Here, we used Rosetta-based computation to design a fluorophore ligase that accepts the red dye resorufin, starting from Escherichia coli lipoic acid ligase. X-ray crystallography showed that the design closely matched the experimental structure. Resorufin ligase catalyzed the site-specific and covalent attachment of resorufin to various cellular proteins genetically fused to a 13-aa recognition peptide in multiple mammalian cell lines and in primary cultured neurons. We used resorufin ligase to perform superresolution imaging of themore » intermediate filament protein vimentin by stimulated emission depletion and electron microscopies. This work illustrates the power of Rosetta for major redesign of enzyme specificity and introduces a tool for minimally invasive, highly specific imaging of cellular proteins by both conventional and superresolution microscopies.« less

Structural Design of a Horizontal-Axis Tidal Current Turbine Composite Blade

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

Bir, G. S.; Lawson, M. J.; Li, Y.

2011-10-01

This paper describes the structural design of a tidal composite blade. The structural design is preceded by two steps: hydrodynamic design and determination of extreme loads. The hydrodynamic design provides the chord and twist distributions along the blade length that result in optimal performance of the tidal turbine over its lifetime. The extreme loads, i.e. the extreme flap and edgewise loads that the blade would likely encounter over its lifetime, are associated with extreme tidal flow conditions and are obtained using a computational fluid dynamics (CFD) software. Given the blade external shape and the extreme loads, we use a laminate-theory-basedmore » structural design to determine the optimal layout of composite laminas such that the ultimate-strength and buckling-resistance criteria are satisfied at all points in the blade. The structural design approach allows for arbitrary specification of the chord, twist, and airfoil geometry along the blade and an arbitrary number of shear webs. In addition, certain fabrication criteria are imposed, for example, each composite laminate must be an integral multiple of its constituent ply thickness. In the present effort, the structural design uses only static extreme loads; dynamic-loads-based fatigue design will be addressed in the future. Following the blade design, we compute the distributed structural properties, i.e. flap stiffness, edgewise stiffness, torsion stiffness, mass, moments of inertia, elastic-axis offset, and center-of-mass offset along the blade. Such properties are required by hydro-elastic codes to model the tidal current turbine and to perform modal, stability, loads, and response analyses.« less

Customizing Monoclonal Antibodies for the Treatment of Methamphetamine Abuse: Current and Future Applications

PubMed Central

Peterson, Eric C.; Gentry, W. Brooks

2015-01-01

Monoclonal antibody-based medications designed to bind (+)-methamphetamine (METH) with high affinity are among the newest approaches to the treatment of METH abuse, and the associated medical complications. The potential clinical indications for these medications include treatment of overdose, reduction of drug dependence, and protection of vulnerable populations from METH-related complications. Research designed to discover and conduct preclinical and clinical testing of these antibodies suggest a scientific vision for how intact mAb (singular and plural) or small antigen binding fragments of mAb could be engineered to optimize the proteins for specific therapeutic applications. In this review we discuss keys to success in this development process including choosing predictors of specificity, efficacy, duration of action, and safety of the medications in disease models of acute and chronic drug abuse. We consider important aspects of METH-like hapten design and how hapten structural features influence specificity and affinity, with an example of a high-resolution x-ray crystal structure of a high affinity antibody to demonstrate this structural relationship. Additionally, several prototype anti-METH mAb forms such as antigen binding fragments (Fab) and single chain variable fragments (scFv) are under development. Unique, customizable aspects of these fragments are presented with specific possible clinical indications. Finally, we discuss clinical trial progress of the first in kind anti-METH mAb, for which the METH is the disease target instead of vulnerable central nervous system networks of receptors, binding sites and neuronal connections. PMID:24484976

Customizing monoclonal antibodies for the treatment of methamphetamine abuse: current and future applications.

PubMed

Peterson, Eric C; Gentry, W Brooks; Owens, S Michael

2014-01-01

Monoclonal antibody-based medications designed to bind (+)-methamphetamine (METH) with high affinity are among the newest approaches to the treatment of METH abuse and the associated medical complications. The potential clinical indications for these medications include treatment of overdose, reduction of drug dependence, and protection of vulnerable populations from METH-related complications. Research designed to discover and conduct preclinical and clinical testing of these antibodies suggests a scientific vision for how intact monoclonal antibody (mAb) (singular and plural) or small antigen-binding fragments of mAb could be engineered to optimize the proteins for specific therapeutic applications. In this review, we discuss keys to success in this development process including choosing predictors of specificity, efficacy, duration of action, and safety of the medications in disease models of acute and chronic drug abuse. We consider important aspects of METH-like hapten design and how hapten structural features influence specificity and affinity, with an example of a high-resolution X-ray crystal structure of a high-affinity antibody to demonstrate this structural relationship. Additionally, several prototype anti-METH mAb forms such as antigen-binding fragments and single-chain variable fragments are under development. Unique, customizable aspects of these fragments are presented with specific possible clinical indications. Finally, we discuss clinical trial progress of the first in kind anti-METH mAb, for which METH is the disease target instead of vulnerable central nervous system networks of receptors, binding sites, and neuronal connections. © 2014 Elsevier Inc. All rights reserved.

Structure-Based Design of Hepatitis C Virus Vaccines That Elicit Neutralizing Antibody Responses to a Conserved Epitope

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

Pierce, Brian G.; Boucher, Elisabeth N.; Piepenbrink, Kurt H.

Despite recent advances in therapeutic options, hepatitis C virus (HCV) remains a severe global disease burden, and a vaccine can substantially reduce its incidence. Due to its extremely high sequence variability, HCV can readily escape the immune response; thus, an effective vaccine must target conserved, functionally important epitopes. Using the structure of a broadly neutralizing antibody in complex with a conserved linear epitope from the HCV E2 envelope glycoprotein (residues 412 to 423; epitope I), we performed structure-based design of immunogens to induce antibody responses to this epitope. This resulted in epitope-based immunogens based on a cyclic defensin protein, asmore » well as a bivalent immunogen with two copies of the epitope on the E2 surface. We solved the X-ray structure of a cyclic immunogen in complex with the HCV1 antibody and confirmed preservation of the epitope conformation and the HCV1 interface. Mice vaccinated with our designed immunogens produced robust antibody responses to epitope I, and their serum could neutralize HCV. Notably, the cyclic designs induced greater epitope-specific responses and neutralization than the native peptide epitope. Beyond successfully designing several novel HCV immunogens, this study demonstrates the principle that neutralizing anti-HCV antibodies can be induced by epitope-based, engineered vaccines and provides the basis for further efforts in structure-based design of HCV vaccines. IMPORTANCEHepatitis C virus is a leading cause of liver disease and liver cancer, with approximately 3% of the world's population infected. To combat this virus, an effective vaccine would have distinct advantages over current therapeutic options, yet experimental vaccines have not been successful to date, due in part to the virus's high sequence variability leading to immune escape. In this study, we rationally designed several vaccine immunogens based on the structure of a conserved epitope that is the target of broadly neutralizing antibodies.In vivoresults in mice indicated that these antigens elicited epitope-specific neutralizing antibodies, with various degrees of potency and breadth. These promising results suggest that a rational design approach can be used to generate an effective vaccine for this virus.« less

Structure-guided Discovery of Dual-recognition Chemibodies.

PubMed

Cheng, Alan C; Doherty, Elizabeth M; Johnstone, Sheree; DiMauro, Erin F; Dao, Jennifer; Luthra, Abhinav; Ye, Jay; Tang, Jie; Nixey, Thomas; Min, Xiaoshan; Tagari, Philip; Miranda, Les P; Wang, Zhulun

2018-05-15

Small molecules and antibodies each have advantages and limitations as therapeutics. Here, we present for the first time to our knowledge, the structure-guided design of "chemibodies" as small molecule-antibody hybrids that offer dual recognition of a single target by both a small molecule and an antibody, using DPP-IV enzyme as a proof of concept study. Biochemical characterization demonstrates that the chemibodies present superior DPP-IV inhibition compared to either small molecule or antibody component alone. We validated our design by successfully solving a co-crystal structure of a chemibody in complex with DPP-IV, confirming specific binding of the small molecule portion at the interior catalytic site and the Fab portion at the protein surface. The discovery of chemibodies presents considerable potential for novel therapeutics that harness the power of both small molecule and antibody modalities to achieve superior specificity, potency, and pharmacokinetic properties.

LH2 fuel tank design for SSTO

NASA Technical Reports Server (NTRS)

Wright, Geoff

1994-01-01

This report will discuss the design of a liquid hydrogen fuel tank constructed from composite materials. The focus of this report is to recommend a design for a fuel tank which will be able to withstand all static and dynamic forces during manned flight. Areas of study for the design include material selection, material structural analysis, heat transfer, thermal expansion, and liquid hydrogen diffusion. A structural analysis FORTRAN program was developed for analyzing the buckling and yield characteristics of the tank. A thermal analysis Excel spreadsheet was created to determine a specific material thickness which will minimize heat transfer through the wall of the tank. The total mass of the tank was determined by the combination of both structural and thermal analyses. The report concludes with the recommendation of a layered material tank construction. The designed system will include exterior insulation, combination of metal and organize composite matrices and honeycomb.

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.

Fragger: a protein fragment picker for structural queries.

PubMed

Berenger, Francois; Simoncini, David; Voet, Arnout; Shrestha, Rojan; Zhang, Kam Y J

2017-01-01

Protein modeling and design activities often require querying the Protein Data Bank (PDB) with a structural fragment, possibly containing gaps. For some applications, it is preferable to work on a specific subset of the PDB or with unpublished structures. These requirements, along with specific user needs, motivated the creation of a new software to manage and query 3D protein fragments. Fragger is a protein fragment picker that allows protein fragment databases to be created and queried. All fragment lengths are supported and any set of PDB files can be used to create a database. Fragger can efficiently search a fragment database with a query fragment and a distance threshold. Matching fragments are ranked by distance to the query. The query fragment can have structural gaps and the allowed amino acid sequences matching a query can be constrained via a regular expression of one-letter amino acid codes. Fragger also incorporates a tool to compute the backbone RMSD of one versus many fragments in high throughput. Fragger should be useful for protein design, loop grafting and related structural bioinformatics tasks.

A computational proposal for designing structured RNA pools for in vitro selection of RNAs.

PubMed

Kim, Namhee; Gan, Hin Hark; Schlick, Tamar

2007-04-01

Although in vitro selection technology is a versatile experimental tool for discovering novel synthetic RNA molecules, finding complex RNA molecules is difficult because most RNAs identified from random sequence pools are simple motifs, consistent with recent computational analysis of such sequence pools. Thus, enriching in vitro selection pools with complex structures could increase the probability of discovering novel RNAs. Here we develop an approach for engineering sequence pools that links RNA sequence space regions with corresponding structural distributions via a "mixing matrix" approach combined with a graph theory analysis. We define five classes of mixing matrices motivated by covariance mutations in RNA; these constructs define nucleotide transition rates and are applied to chosen starting sequences to yield specific nonrandom pools. We examine the coverage of sequence space as a function of the mixing matrix and starting sequence via clustering analysis. We show that, in contrast to random sequences, which are associated only with a local region of sequence space, our designed pools, including a structured pool for GTP aptamers, can target specific motifs. It follows that experimental synthesis of designed pools can benefit from using optimized starting sequences, mixing matrices, and pool fractions associated with each of our constructed pools as a guide. Automation of our approach could provide practical tools for pool design applications for in vitro selection of RNAs and related problems.

The analysis of tensegrity structures for the design of a morphing wing

NASA Astrophysics Data System (ADS)

Moored, Keith W., III; Bart-Smith, Hilary

2005-05-01

Tensegrity structures have become of engineering interest in recent years, but very few have found practical use. This lack of integration is attributed to the lack of a well formulated design procedure. In this paper, a preliminary procedure is presented for developing morphing tensegrity structures that include actuating elements. To do this, the virtual work method has been modified to allow for individual actuation of struts and cables. A generalized connectivity matrix for a cantilever beam constructed from either a single 4-strut cell or multiple 4-strut cells has been developed. Global deflections resulting from actuation of specific elements have been calculated. Furthermore, the force density method is expanded to include a necessary upper bound condition such that a physically feasible structure can be designed. Finally, the importance of relative force density values on the overall shape of a structure comprising of multiple unit cells is discussed.

Floor vibration evaluations for medical facilities

NASA Astrophysics Data System (ADS)

Himmel, Chad N.

2003-10-01

The structural floor design for new medical facilities is often selected early in the design phase and in renovation projects, the floor structure already exists. Because the floor structure can often have an influence on the location of vibration sensitive medical equipment and facilities, it is becoming necessary to identify the best locations for equipment and facilities early in the design process. Even though specific criteria for vibration-sensitive uses and equipment may not always be available early in the design phase, it should be possible to determine compatible floor structures for planned vibration-sensitive uses by comparing conceptual layouts with generic floor vibration criteria. Relatively simple evaluations of planned uses and generic criteria, combined with on-site vibration and noise measurements early in design phase, can significantly reduce future design problems and expense. Concepts of evaluation procedures and analyses will be presented in this paper. Generic floor vibration criteria and appropriate parameters to control resonant floor vibration and noise will be discussed for typical medical facilities and medical research facilities. Physical, economic, and logistical limitations that affect implementation will be discussed through case studies.

Computational design of RNAs with complex energy landscapes.

PubMed

Höner zu Siederdissen, Christian; Hammer, Stefan; Abfalter, Ingrid; Hofacker, Ivo L; Flamm, Christoph; Stadler, Peter F

2013-12-01

RNA has become an integral building material in synthetic biology. Dominated by their secondary structures, which can be computed efficiently, RNA molecules are amenable not only to in vitro and in vivo selection, but also to rational, computation-based design. While the inverse folding problem of constructing an RNA sequence with a prescribed ground-state structure has received considerable attention for nearly two decades, there have been few efforts to design RNAs that can switch between distinct prescribed conformations. We introduce a user-friendly tool for designing RNA sequences that fold into multiple target structures. The underlying algorithm makes use of a combination of graph coloring and heuristic local optimization to find sequences whose energy landscapes are dominated by the prescribed conformations. A flexible interface allows the specification of a wide range of design goals. We demonstrate that bi- and tri-stable "switches" can be designed easily with moderate computational effort for the vast majority of compatible combinations of desired target structures. RNAdesign is freely available under the GPL-v3 license. Copyright © 2013 Wiley Periodicals, Inc.

Molecular biomimetics: GEPI-based biological routes to technology.

PubMed

Tamerler, Candan; Khatayevich, Dmitriy; Gungormus, Mustafa; Kacar, Turgay; Oren, E Emre; Hnilova, Marketa; Sarikaya, Mehmet

2010-01-01

In nature, the viability of biological systems is sustained via specific interactions among the tens of thousands of proteins, the major building blocks of organisms from the simplest single-celled to the most complex multicellular species. Biomolecule-material interaction is accomplished with molecular specificity and efficiency leading to the formation of controlled structures and functions at all scales of dimensional hierarchy. Through evolution, Mother Nature developed molecular recognition by successive cycles of mutation and selection. Molecular specificity of probe-target interactions, e.g., ligand-receptor, antigen-antibody, is always based on specific peptide molecular recognition. Using biology as a guide, we can now understand, engineer, and control peptide-material interactions and exploit them as a new design tool for novel materials and systems. We adapted the protocols of combinatorially designed peptide libraries, via both cell surface or phage display methods; using these we select short peptides with specificity to a variety of practical materials. These genetically engineered peptides for inorganics (GEPI) are then studied experimentally to establish their binding kinetics and surface stability. The bound peptide structure and conformations are interrogated both experimentally and via modeling, and self-assembly characteristics are tested via atomic force microscopy. We further engineer the peptide binding and assembly characteristics using a computational biomimetics approach where bioinformatics based peptide-sequence similarity analysis is developed to design higher generation function-specific peptides. The molecular biomimetic approach opens up new avenues for the design and utilization of multifunctional molecular systems in a wide-range of applications from tissue engineering, disease diagnostics, and therapeutics to various areas of nanotechnology where integration is required among inorganic, organic and biological materials. Here, we describe lessons from biology with examples of protein-mediated functional biological materials, explain how novel peptides can be designed with specific affinity to inorganic solids using evolutionary engineering approaches, give examples of their potential utilizations in technology and medicine, and, finally, provide a summary of challenges and future prospects. (c) 2010 Wiley Periodicals, Inc.

RNAfbinv: an interactive Java application for fragment-based design of RNA sequences.

PubMed

Weinbrand, Lina; Avihoo, Assaf; Barash, Danny

2013-11-15

In RNA design problems, it is plausible to assume that the user would be interested in preserving a particular RNA secondary structure motif, or fragment, for biological reasons. The preservation could be in structure or sequence, or both. Thus, the inverse RNA folding problem could benefit from considering fragment constraints. We have developed a new interactive Java application called RNA fragment-based inverse that allows users to insert an RNA secondary structure in dot-bracket notation. It then performs sequence design that conforms to the shape of the input secondary structure, the specified thermodynamic stability, the specified mutational robustness and the user-selected fragment after shape decomposition. In this shape-based design approach, specific RNA structural motifs with known biological functions are strictly enforced, while others can possess more flexibility in their structure in favor of preserving physical attributes and additional constraints. RNAfbinv is freely available for download on the web at http://www.cs.bgu.ac.il/~RNAexinv/RNAfbinv. The site contains a help file with an explanation regarding the exact use.

Study of the effects of wind power and vortex-induced vibrations to establish fatigue design criteria for high-mast poles.

DOT National Transportation Integrated Search

2011-08-01

Traffic signal and high-mast poles are used by transportation agencies to control and illuminate intersections; their structural design is governed by national specifications. High-mast poles are luminaire supports located near highway interchanges t...

Mechanics of Multifunctional Materials & Microsystems

DTIC Science & Technology

2012-03-09

Mechanics of Materials; Life Prediction (Materials & Micro-devices); Sensing, Precognition & Diagnosis; Multifunctional Design of Autonomic...Life Prediction (Materials & Micro-devices); Sensing, Precognition & Diagnosis; Multifunctional Design of Autonomic Systems; Multifunctional...release; distribution is unlimited. 7 VISION: EXPANDED • site specific • autonomic AUTONOMIC AEROSPACE STRUCTURES • Sensing & Precognition • Self

Advanced Metallic Thermal Protection System Development

NASA Technical Reports Server (NTRS)

Blosser, M. L.; Chen, R. R.; Schmidt, I. H.; Dorsey, J. T.; Poteet, C. C.; Bird, R. K.

2002-01-01

A new Adaptable, Robust, Metallic, Operable, Reusable (ARMOR) thermal protection system (TPS) concept has been designed, analyzed, and fabricated. In addition to the inherent tailorable robustness of metallic TPS, ARMOR TPS offers improved features based on lessons learned from previous metallic TPS development efforts. A specific location on a single-stage-to-orbit reusable launch vehicle was selected to develop loads and requirements needed to design prototype ARMOR TPS panels. The design loads include ascent and entry heating rate histories, pressures, acoustics, and accelerations. Additional TPS design issues were identified and discussed. An iterative sizing procedure was used to size the ARMOR TPS panels for thermal and structural loads as part of an integrated TPS/cryogenic tank structural wall. The TPS panels were sized to maintain acceptable temperatures on the underlying structure and to operate under the design structural loading. Detailed creep analyses were also performed on critical components of the ARMOR TPS panels. A lightweight, thermally compliant TPS support system (TPSS) was designed to connect the TPS to the cryogenic tank structure. Four 18-inch-square ARMOR TPS panels were fabricated. Details of the fabrication process are presented. Details of the TPSS for connecting the ARMOR TPS panels to the externally stiffened cryogenic tank structure are also described. Test plans for the fabricated hardware are presented.

Satisfaction and Achievement: Antagonists in ATI Research on Classroom Structure.

ERIC Educational Resources Information Center

Strom, Bruce; And Others

To date, the constructive motivation hypothesis has generally been limited to educational achievement as an outcome variable, and few studies have been specifically designed to investigate student satisfaction outcomes. To measure student preferences for course structure and difficulty level and student perceptions of instructors' orientation…

The design strategy of selective PTP1B inhibitors over TCPTP.

PubMed

Li, XiangQian; Wang, LiJun; Shi, DaYong

2016-08-15

Protein tyrosine phosphatase 1B (PTP1B) has already been well studied as a highly validated therapeutic target for diabetes and obesity. However, the lack of selectivity limited further studies and clinical applications of PTP1B inhibitors, especially over T-cell protein tyrosine phosphatase (TCPTP). In this review, we enumerate the published specific inhibitors of PTP1B, discuss the structure-activity relationships by analysis of their X-ray structures or docking results, and summarize the characteristic of selectivity related residues and groups. Furthermore, the design strategy of selective PTP1B inhibitors over TCPTP is also proposed. We hope our work could provide an effective way to gain specific PTP1B inhibitors. Copyright © 2016 Elsevier Ltd. All rights reserved.

Space Shuttle Orbiter Structures and Mechanisms

NASA Technical Reports Server (NTRS)

Gilmore, Adam L.; Estes, Lynda R.; Eilers, James A.; Logan, Jeffrey S.; Evernden, Brent A.; Decker, William S.; Hagen, Jeffrey D.; Davis, Robert E.; Broughton, James K.; Campbell, Carlisle C.;

Structures, Material and Processes Technology in the Future Launchers Preparatory Program

NASA Astrophysics Data System (ADS)

Baiocco, P.; Ramusat, G.; Breteau, J.; Bouilly, Th.; Lavelle, Fl.; Cardone, T.; Fischer, H.; Appel, S.; Block, U.

2014-06-01

In the frame of the technology / demonstration activity for European launchers developments and evolutions, a top-down / bottom-up approach has been employed to identify promising technologies and alternative conception. The top-down approach consists in looking for system-driven design solutions and the bottom-up approach features design solutions leading to substantial advantages for the system. The main investigations have been devoted to structures, material and process technology.Preliminary specifications have been used in order to permit sub-system design with the goal to find the major benefit for the overall launch system. In this respect competitiveness factors have been defined to down- select the technology and the corresponding optimized design. The development cost, non-recurring cost, industrialization and operational aspects have been considered for the identification of the most interesting solutions. The TRL/IRL has been assessed depending on the manufacturing company and a preliminary development plan has been issued for some technology.The reference launch systems for the technology and demonstration programs are mainly Ariane 6 with its evolutions, VEGA C/E and others possible longer term systems. Requirements and reference structures architectures have been considered in order to state requirements for representative subscale or full scale demonstrators. The major sub-systems and structures analyzed are for instance the upper stage structures, the engine thrust frame (ETF), the inter stage structures (ISS), the cryogenic propellant tanks, the feeding lines and their attachments, the pressurization systems, the payload adapters and fairings. A specific analysis has been devoted to the efficiency of production processes associated to technologies and design features.The paper provides an overview of the main results of the technology and demonstration activities with the associated system benefits. The materials used for the main structures are metallic and composite owing to sub-systems or sub-assemblies proposed for the European launch systems in development and their evolutions.

Research requirements to reduce empty weight of helicopters by use of advanced materials

NASA Technical Reports Server (NTRS)

Hoffstedt, D. J.

1976-01-01

Utilization of the new, lightweight, high-strength, aerospace structural-composite (filament/matrix) materials, when specifically designed into a new aircraft, promises reductions in structural empty weight of 12 percent at recurring costs competive with metals. A program of basic and applied research and demonstration is identified with the objective of advancing the state of the art to the point where civil helicopters are confidently designed, produced, certified, and marketed by 1985. A structural empty-weight reduction of 12 percent was shown to significantly reduce energy consumption in modern high-performance helicopters.

Development and Application of a Systems Engineering Framework to Support Online Course Design and Delivery

ERIC Educational Resources Information Center

Bozkurt, Ipek; Helm, James

2013-01-01

This paper develops a systems engineering-based framework to assist in the design of an online engineering course. Specifically, the purpose of the framework is to provide a structured methodology for the design, development and delivery of a fully online course, either brand new or modified from an existing face-to-face course. The main strength…

Design and control considerations for industrial and space manipulators

NASA Technical Reports Server (NTRS)

Whitney, D. E.; Book, W. J.; Lynch, P. M.

1974-01-01

This paper is a progress report summarizing theoretical and practical results concerning integration of design and control aspects of manipulator arms for industrial or space applications. The relationships between task specifications, gross motions, fine motions, actuator type and location, size and strength of structural members, control servos and strategies, and overall design evaluation are briefly discussed, with some technical examples.

RNAblueprint: flexible multiple target nucleic acid sequence design.

PubMed

Hammer, Stefan; Tschiatschek, Birgit; Flamm, Christoph; Hofacker, Ivo L; Findeiß, Sven

2017-09-15

Realizing the value of synthetic biology in biotechnology and medicine requires the design of molecules with specialized functions. Due to its close structure to function relationship, and the availability of good structure prediction methods and energy models, RNA is perfectly suited to be synthetically engineered with predefined properties. However, currently available RNA design tools cannot be easily adapted to accommodate new design specifications. Furthermore, complicated sampling and optimization methods are often developed to suit a specific RNA design goal, adding to their inflexibility. We developed a C ++  library implementing a graph coloring approach to stochastically sample sequences compatible with structural and sequence constraints from the typically very large solution space. The approach allows to specify and explore the solution space in a well defined way. Our library also guarantees uniform sampling, which makes optimization runs performant by not only avoiding re-evaluation of already found solutions, but also by raising the probability of finding better solutions for long optimization runs. We show that our software can be combined with any other software package to allow diverse RNA design applications. Scripting interfaces allow the easy adaption of existing code to accommodate new scenarios, making the whole design process very flexible. We implemented example design approaches written in Python to demonstrate these advantages. RNAblueprint , Python implementations and benchmark datasets are available at github: https://github.com/ViennaRNA . s.hammer@univie.ac.at, ivo@tbi.univie.ac.at or sven@tbi.univie.ac.at. Supplementary data are available at Bioinformatics online. © The Author(s) 2017. Published by Oxford University Press.

An Analysis of the Organizational Structure of Redstone Test Centers Environmental and Components Test Directorate With Regard to Instrumentation Design Capabilities

DTIC Science & Technology

2016-09-01

NAVAL POSTGRADUATE SCHOOL MONTEREY, CALIFORNIA JOINT APPLIED PROJECT AN ANALYSIS OF THE ORGANIZATIONAL STRUCTURE OF REDSTONE...AND SUBTITLE AN ANALYSIS OF THE ORGANIZATIONAL STRUCTURE OF REDSTONE TEST CENTER’S ENVIRONMENTAL AND COMPONENTS TEST DIRECTORATE WITH REGARD TO...provides an analysis of the organizational structure of Redstone Test Center’s Environment and Components Test Directorate, with specific regard to

Design and analysis of optimised class E power amplifier using shunt capacitance in the output structure

NASA Astrophysics Data System (ADS)

Hayati, Mohsen; Roshani, Sobhan; Zirak, Ali Reza

2017-05-01

In this paper, a class E power amplifier (PA) with operating frequency of 1 MHz is presented. MOSFET non-linear drain-to-source parasitic capacitance, linear external capacitance at drain-to-source port and linear shunt capacitance in the output structure are considered in design theory. One degree of freedom is added to the design of class E PA, by assuming the shunt capacitance in the output structure in the analysis. With this added design degree of freedom it is possible to achieve desired values for several parameters, such as output voltage, load resistance and operating frequency, while both zero voltage and zero derivative switching (ZVS and ZDS) conditions are satisfied. In the conventional class E PA, high value of peak switch voltage results in limitations for the design of amplifier, while in the presented structure desired specifications could be achieved with the safe margin of peak switch voltage. The results show that higher operating frequency and output voltage can also be achieved, compared to the conventional structure. PSpice software is used in order to simulate the designed circuit. The presented class E PA is designed, fabricated and measured. The measured results are in good agreement with simulation and theory results.

Integrated performance and reliability specification for digital avionics systems

NASA Technical Reports Server (NTRS)

Brehm, Eric W.; Goettge, Robert T.

1995-01-01

This paper describes an automated tool for performance and reliability assessment of digital avionics systems, called the Automated Design Tool Set (ADTS). ADTS is based on an integrated approach to design assessment that unifies traditional performance and reliability views of system designs, and that addresses interdependencies between performance and reliability behavior via exchange of parameters and result between mathematical models of each type. A multi-layer tool set architecture has been developed for ADTS that separates the concerns of system specification, model generation, and model solution. Performance and reliability models are generated automatically as a function of candidate system designs, and model results are expressed within the system specification. The layered approach helps deal with the inherent complexity of the design assessment process, and preserves long-term flexibility to accommodate a wide range of models and solution techniques within the tool set structure. ADTS research and development to date has focused on development of a language for specification of system designs as a basis for performance and reliability evaluation. A model generation and solution framework has also been developed for ADTS, that will ultimately encompass an integrated set of analytic and simulated based techniques for performance, reliability, and combined design assessment.

Hierarchical and hybrid energy storage devices in data centers: Architecture, control and provisioning.

PubMed

Sun, Mengshu; Xue, Yuankun; Bogdan, Paul; Tang, Jian; Wang, Yanzhi; Lin, Xue

2018-01-01

Recently, a new approach has been introduced that leverages and over-provisions energy storage devices (ESDs) in data centers for performing power capping and facilitating capex/opex reductions, without performance overhead. To fully realize the potential benefits of the hierarchical ESD structure, we propose a comprehensive design, control, and provisioning framework including (i) designing power delivery architecture supporting hierarchical ESD structure and hybrid ESDs for some levels, as well as (ii) control and provisioning of the hierarchical ESD structure including run-time ESD charging/discharging control and design-time determination of ESD types, homogeneous/hybrid options, ESD provisioning at each level. Experiments have been conducted using real Google data center workloads based on realistic data center specifications.

Hierarchical and hybrid energy storage devices in data centers: Architecture, control and provisioning

PubMed Central

Xue, Yuankun; Bogdan, Paul; Tang, Jian; Wang, Yanzhi; Lin, Xue

2018-01-01

Recently, a new approach has been introduced that leverages and over-provisions energy storage devices (ESDs) in data centers for performing power capping and facilitating capex/opex reductions, without performance overhead. To fully realize the potential benefits of the hierarchical ESD structure, we propose a comprehensive design, control, and provisioning framework including (i) designing power delivery architecture supporting hierarchical ESD structure and hybrid ESDs for some levels, as well as (ii) control and provisioning of the hierarchical ESD structure including run-time ESD charging/discharging control and design-time determination of ESD types, homogeneous/hybrid options, ESD provisioning at each level. Experiments have been conducted using real Google data center workloads based on realistic data center specifications. PMID:29351553

Effects of Flame Structure and Hydrodynamics on Soot Particle Inception and Flame Extinction in Diffusion Flames

NASA Technical Reports Server (NTRS)

Axelbaum, R. L.; Chen, R.; Sunderland, P. B.; Urban, D. L.; Liu, S.; Chao, B. H.

2001-01-01

This paper summarizes recent studies of the effects of stoichiometric mixture fraction (structure) and hydrodynamics on soot particle inception and flame extinction in diffusion flames. Microgravity experiments are uniquely suited for these studies because, unlike normal gravity experiments, they allow structural and hydrodynamic effects to be independently studied. As part of this recent flight definition program, microgravity studies have been performed in the 2.2 second drop tower. Normal gravity counterflow studies also have been employed and analytical and numerical models have been developed. A goal of this program is to develop sufficient understanding of the effects of flame structure that flames can be "designed" to specifications - consequently, the program name Flame Design. In other words, if a soot-free, strong, low temperature flame is required, can one produce such a flame by designing its structure? Certainly, as in any design, there will be constraints imposed by the properties of the available "materials." For hydrocarbon combustion, the base materials are fuel and air. Additives could be considered, but for this work only fuel, oxygen and nitrogen are considered. Also, the structure of these flames is "designed" by varying the stoichiometric mixture fraction. Following this line of reasoning, the studies described are aimed at developing the understanding of flame structure that is needed to allow for optimum design.

Indexing Learning Objects: Vocabularies and Empirical Investigation of Consistency

ERIC Educational Resources Information Center

Kabel, Suzanne; De Hoog, Robert; Wielinga, Bob; Anjewierden, Anjo

2004-01-01

In addition to the LOM standard and instructional design specifications, as well as domain specific indexing vocabularies, a structured indexing vocabulary for the more elementary learning objects is advisable in order to support retrieval tasks of developers. Furthermore, because semantic indexing is seen as a difficult task, three issues…

Structural analysis consultation using artificial intelligence

NASA Technical Reports Server (NTRS)

Melosh, R. J.; Marcal, P. V.; Berke, L.

1978-01-01

The primary goal of consultation is definition of the best strategy to deal with a structural engineering analysis objective. The knowledge base to meet the need is designed to identify the type of numerical analysis, the needed modeling detail, and specific analysis data required. Decisions are constructed on the basis of the data in the knowledge base - material behavior, relations between geometry and structural behavior, measures of the importance of time and temperature changes - and user supplied specifics characteristics of the spectrum of analysis types, the relation between accuracy and model detail on the structure, its mechanical loadings, and its temperature states. Existing software demonstrated the feasibility of the approach, encompassing the 36 analysis classes spanning nonlinear, temperature affected, incremental analyses which track the behavior of structural systems.

Templated Synthesis of Single-Walled Carbon Nanotubes with Specific Structure.

PubMed

Yang, Feng; Wang, Xiao; Li, Meihui; Liu, Xiyan; Zhao, Xiulan; Zhang, Daqi; Zhang, Yan; Yang, Juan; Li, Yan

2016-04-19

Single-walled carbon nanotubes (SWNTs) have shown great potential in various applications attributed to their unique structure-dependent properties. Therefore, the controlled preparation of chemically and structurally pristine SWNTs is a crucial issue for their advanced applications (e.g., nanoelectronics) and has been a great challenge for two decades. Epitaxial growth from well-defined seeds has been shown to be a promising strategy to control the structure of SWNTs. Segments of carbon nanotubes, including short pipes from cutting of preformed nanotubes and caps from opening of fullerenes or cyclodehydrogenation of polycyclic hydrocarbon precursors, have been used as the seeds to grow SWNTs. Single-chirality SWNTs were obtained with both presorted chirality-pure SWNT segments and end caps obtained from polycyclic hydrocarbon molecules with designed structure. The main challenges of nanocarbon-segment-seeded processes are the stability of the seeds, yield, and efficiency. Catalyst-mediated SWNT growth is believed to be more efficient. The composition and morphology of the catalyst nanoparticles have been widely reported to affect the chirality distribution of SWNTs. However, chirality-specific SWNT growth is hard to achieve by alternating catalysts. The specificity of enzyme-catalyzed reactions brings us an awareness of the essentiality of a unique catalyst structure for the chirality-selective growth of SWNTs. Only catalysts with the desired atomic arrangements in their crystal planes can act as structural templates for chirality-specific growth of SWNTs. We have developed a new family of catalysts, tungsten-based intermetallic compounds, which have high melting points and very special crystal structures, to facilitate the growth of SWNTs with designed chirality. By the use of W6Co7 catalysts, (12,6) SWNTs were directly grown with purity higher than 92%. Both high-resolution transmission electron microscopy measurements and density functional theory simulations show that the selective growth of (12,6) tubes is due to a good structural match between the carbon atom arrangement around the nanotube circumference and the metal atom arrangement of (0 0 12) planes in the catalyst. Similarly, (16,0) SWNTs exhibit a good structural match to the (116) planes of the W6Co7 catalyst. By optimization of the chemical vapor deposition (CVD) conditions, zigzag (16,0) SWNTs, which are generally known as a kinetically unfavorable species in CVD growth, were obtained with a purity of ∼80%. Generally speaking, the chirality-specific growth of SWNTs is realized by the cooperation of two factors: the structural match between SWNTs and the catalysts makes the growth of SWNTs with specific chirality thermodynamically favorable, and further manipulation of the CVD conditions results in optimized growth kinetics for SWNTs with this designed chirality. We expect that this advanced epitaxial growth strategy will pave the way for the ultimate goal of chirality-specified growth of SWNTs and will also be applicable in the controlled preparation of other nanomaterials.

FILTSoft: A computational tool for microstrip planar filter design

NASA Astrophysics Data System (ADS)

Elsayed, M. H.; Abidin, Z. Z.; Dahlan, S. H.; Cholan N., A.; Ngu, Xavier T. I.; Majid, H. A.

2017-09-01

Filters are key component of any communication system to control spectrum and suppress interferences. Designing a filter involves long process as well as good understanding of the basic hardware technology. Hence this paper introduces an automated design tool based on Matlab-GUI, called the FILTSoft (acronym for Filter Design Software) to ease the process. FILTSoft is a user friendly filter design tool to aid, guide and expedite calculations from lumped elements level to microstrip structure. Users just have to provide the required filter specifications as well as the material description. FILTSoft will calculate and display the lumped element details, the planar filter structure, and the expected filter's response. An example of a lowpass filter design was calculated using FILTSoft and the results were validated through prototype measurement for comparison purposes.

Sharing Data between Mobile Devices, Connected Vehicles and Infrastructure Task 4 / Task 10 : System Architecture and Design Document (SA/DD).

DOT National Transportation Integrated Search

2017-10-27

This report describes the system architecture and design of the Experimental Prototype System (EPS) for the demonstration of the use of mobile devices in a connected vehicle environment. Specifically, it defines the system structure and behavior, the...

The Design Process of Corporate Universities: A Stakeholder Approach

ERIC Educational Resources Information Center

Patrucco, Andrea Stefano; Pellizzoni, Elena; Buganza, Tommaso

2017-01-01

Purpose: Corporate universities (CUs) have been experiencing tremendous growth during the past years and can represent a real driving force for structured organizations. The paper aims to define the process of CU design shaped around company strategy. For each step, the authors propose specific roles, activities and methods.…

Transformation of the Schoolhouse. Annual Report for 1969.

ERIC Educational Resources Information Center

Coughlin, Gaila, Ed.

This report reviews some of the more important educational innovations that have transformed the arrangement of space and design of the schoolhouse environment. Design, structural, and functional features are described for open plan schools (schools without interior walls). Consideration is given to the use of performance specifications in the…

Structural insights into species-specific features of the ribosome from the pathogen Staphylococcus aureus

PubMed Central

Eyal, Zohar; Matzov, Donna; Krupkin, Miri; Wekselman, Itai; Paukner, Susanne; Zimmerman, Ella; Rozenberg, Haim; Bashan, Anat; Yonath, Ada

2015-01-01

The emergence of bacterial multidrug resistance to antibiotics threatens to cause regression to the preantibiotic era. Here we present the crystal structure of the large ribosomal subunit from Staphylococcus aureus, a versatile Gram-positive aggressive pathogen, and its complexes with the known antibiotics linezolid and telithromycin, as well as with a new, highly potent pleuromutilin derivative, BC-3205. These crystal structures shed light on specific structural motifs of the S. aureus ribosome and the binding modes of the aforementioned antibiotics. Moreover, by analyzing the ribosome structure and comparing it with those of nonpathogenic bacterial models, we identified some unique internal and peripheral structural motifs that may be potential candidates for improving known antibiotics and for use in the design of selective antibiotic drugs against S. aureus. PMID:26464510

10 CFR 52.47 - Contents of applications; technical information.

Code of Federal Regulations, 2013 CFR

2013-01-01

... accidents, e.g., challenges to containment integrity caused by core-concrete interaction, steam explosion... such as the service water intake structure and the ultimate heat sink; (2) An application for... design except for site-specific elements such as the service water intake structure and the ultimate heat...

10 CFR 52.47 - Contents of applications; technical information.

Code of Federal Regulations, 2010 CFR

2010-01-01

... accidents, e.g., challenges to containment integrity caused by core-concrete interaction, steam explosion... such as the service water intake structure and the ultimate heat sink; (2) An application for... design except for site-specific elements such as the service water intake structure and the ultimate heat...

10 CFR 52.47 - Contents of applications; technical information.

Code of Federal Regulations, 2011 CFR

2011-01-01

... accidents, e.g., challenges to containment integrity caused by core-concrete interaction, steam explosion... such as the service water intake structure and the ultimate heat sink; (2) An application for... design except for site-specific elements such as the service water intake structure and the ultimate heat...

10 CFR 52.47 - Contents of applications; technical information.

Code of Federal Regulations, 2014 CFR

2014-01-01

... accidents, e.g., challenges to containment integrity caused by core-concrete interaction, steam explosion... such as the service water intake structure and the ultimate heat sink; (2) An application for... design except for site-specific elements such as the service water intake structure and the ultimate heat...

10 CFR 52.47 - Contents of applications; technical information.

Code of Federal Regulations, 2012 CFR

2012-01-01

... accidents, e.g., challenges to containment integrity caused by core-concrete interaction, steam explosion... such as the service water intake structure and the ultimate heat sink; (2) An application for... design except for site-specific elements such as the service water intake structure and the ultimate heat...

33 CFR 148.8 - How are certifying entities designated and used for purposes of this subchapter?

Code of Federal Regulations, 2013 CFR

2013-07-01

... be associated with the CE's duties for the specific project; (7) In-house availability of, or access to, appropriate technology such as computer modeling programs and hardware or testing materials and...-based structures and project-related structures, systems, and equipment; (6) Technical capabilities...

33 CFR 148.8 - How are certifying entities designated and used for purposes of this subchapter?

Code of Federal Regulations, 2014 CFR

2014-07-01

... be associated with the CE's duties for the specific project; (7) In-house availability of, or access to, appropriate technology such as computer modeling programs and hardware or testing materials and...-based structures and project-related structures, systems, and equipment; (6) Technical capabilities...

A Framework for the Instructional Design of Multi-Structured Educational Applications.

ERIC Educational Resources Information Center

Buendia, F.; Diaz, P.; Benlloch, J. V.

An instructional application consists of a set of resources and activities that implement interacting, interrelated and structured experiences oriented towards achieving specific educational objectives. Computer-based instructional applications have to be looked at as any other development activity following a well defined process. With this…

Trends in aerospace structures

NASA Technical Reports Server (NTRS)

Card, M. F.

1978-01-01

Recent developments indicate that there may soon be a revolution in aerospace structures. Increases in allowable operational stress levels, utilization of high-strength, high-toughness materials, and new structural concepts will highlight this advancement. Improved titanium and aluminum alloys and high-modulus, high-strength advanced composites, with higher specific properties than aluminum and high-strength nickel alloys, are expected to be the principal materials. Significant advances in computer technology will cause major changes in the preliminary design cycle and permit solutions of otherwise too-complex interactive structural problems and thus the development of vehicles and components of higher performance. The energy crisis will have an impact on material costs and choices and will spur the development of more weight-efficient structures. There will also be significant spinoffs of aerospace structures technology, particularly in composites and design/analysis software.

Optimization of monopiles for offshore wind turbines.

PubMed

Kallehave, Dan; Byrne, Byron W; LeBlanc Thilsted, Christian; Mikkelsen, Kristian Kousgaard

2015-02-28

The offshore wind industry currently relies on subsidy schemes to be competitive with fossil-fuel-based energy sources. For the wind industry to survive, it is vital that costs are significantly reduced for future projects. This can be partly achieved by introducing new technologies and partly through optimization of existing technologies and design methods. One of the areas where costs can be reduced is in the support structure, where better designs, cheaper fabrication and quicker installation might all be possible. The prevailing support structure design is the monopile structure, where the simple design is well suited to mass-fabrication, and the installation approach, based on conventional impact driving, is relatively low-risk and robust for most soil conditions. The range of application of the monopile for future wind farms can be extended by using more accurate engineering design methods, specifically tailored to offshore wind industry design. This paper describes how state-of-the-art optimization approaches are applied to the design of current wind farms and monopile support structures and identifies the main drivers where more accurate engineering methods could impact on a next generation of highly optimized monopiles. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

Automated design evolution of stereochemically randomized protein foldamers

NASA Astrophysics Data System (ADS)

Ranbhor, Ranjit; Kumar, Anil; Patel, Kirti; Ramakrishnan, Vibin; Durani, Susheel

2018-05-01

Diversification of chain stereochemistry opens up the possibilities of an ‘in principle’ increase in the design space of proteins. This huge increase in the sequence and consequent structural variation is aimed at the generation of smart materials. To diversify protein structure stereochemically, we introduced L- and D-α-amino acids as the design alphabet. With a sequence design algorithm, we explored the usage of specific variables such as chirality and the sequence of this alphabet in independent steps. With molecular dynamics, we folded stereochemically diverse homopolypeptides and evaluated their ‘fitness’ for possible design as protein-like foldamers. We propose a fitness function to prune the most optimal fold among 1000 structures simulated with an automated repetitive simulated annealing molecular dynamics (AR-SAMD) approach. The highly scored poly-leucine fold with sequence lengths of 24 and 30 amino acids were later sequence-optimized using a Dead End Elimination cum Monte Carlo based optimization tool. This paper demonstrates a novel approach for the de novo design of protein-like foldamers.

Protein-based hydrogels for tissue engineering

PubMed Central

Schloss, Ashley C.; Williams, Danielle M.; Regan, Lynne J.

2017-01-01

The tunable mechanical and structural properties of protein-based hydrogels make them excellent scaffolds for tissue engineering and repair. Moreover, using protein-based components provides the option to insert sequences associated with the promoting both cellular adhesion to the substrate and overall cell growth. Protein-based hydrogel components are appealing for their structural designability, specific biological functionality, and stimuli-responsiveness. Here we present highlights in the field of protein-based hydrogels for tissue engineering applications including design requirements, components, and gel types. PMID:27677513

Development of Micro Air Vehicle Technology With In-Flight Adaptive-Wing Structure

NASA Technical Reports Server (NTRS)

Waszak, Martin R. (Technical Monitor); Shkarayev, Sergey; Null, William; Wagner, Matthew

2004-01-01

This is a final report on the research studies, "Development of Micro Air Vehicle Technology with In-Flight Adaptrive-Wing Structure". This project involved the development of variable-camber technology to achieve efficient design of micro air vehicles. Specifically, it focused on the following topics: 1) Low Reynolds number wind tunnel testing of cambered-plate wings. 2) Theoretical performance analysis of micro air vehicles. 3) Design of a variable-camber MAV actuated by micro servos. 4) Test flights of a variable-camber MAV.

Application of the QSDC procedure to the formulation of space shuttle design criteria. Volume 2: Applications guide

NASA Technical Reports Server (NTRS)

Bouton, I.; Martin, G. L.

1972-01-01

Criteria to determine the probability of aircraft structural failure were established according to the Quantitative Structural Design Criteria by Statistical Methods, the QSDC Procedure. This criteria method was applied to the design of the space shuttle during this contract. An Applications Guide was developed to demonstrate the utilization of the QSDC Procedure, with examples of the application to a hypothetical space shuttle illustrating the application to specific design problems. Discussions of the basic parameters of the QSDC Procedure: the Limit and Omega Conditions, and the strength scatter, have been included. Available data pertinent to the estimation of the strength scatter have also been included.

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

Not Available

The Performance Prototype Trough (PPT) Concentrating Collector consists of four 80-foot modules in a 320-foot row. The collector was analyzed, including cost estimates and manufacturing processes to produce collectors in volumes from 100 to 100,000 modules per year. The four different reflector concepts considered were the sandwich reflector structure, sheet metal reflector structure, molded reflector structure, and glass laminate structure. The sheet metal and glass laminate structures are emphasized with their related structure concepts. A preliminary manufacturing plan is offered that includes: documentation of the manufacturing process with production flow diagrams; labor and material costs at various production levels; machinerymore » and equipment requirements including preliminary design specifications; and capital investment costs for a new plant. Of five reflector designs considered, the two judged best and considered at length are thin annealed glass and steel laminate on steel frame panel and thermally sagged glass. Also discussed are market considerations, costing and selling price estimates, design cost analysis and make/buy analysis. (LEW)« less

Auxetic hexachiral structures with wavy ligaments for large elasto-plastic deformation

NASA Astrophysics Data System (ADS)

Zhu, Yilin; Wang, Zhen-Pei; Hien Poh, Leong

2018-05-01

The hexachiral structure is in-plane isotropic in small deformation. When subjected to large elasto-plastic deformation, however, the hexachiral structure tends to lose its auxeticity and/or isotropy—properties which are desirable in many potential applications. The objective of this study is to improve these two mechanical properties, without significantly compromising the effective yield stress, in the regime with significant material and geometrical nonlinearity effects. It is found that the deformation mechanisms underlying the auxeticity and isotropy properties of a hexachiral structure are largely influenced by the extent of rotation of the central ring in a unit cell. To facilitate the development of this deformation mechanism, an improved design with wavy ligaments is proposed. The improved performance of the proposed hexachiral structure is demonstrated. An initial study on possible applications as a protective material is next carried out, where the improved hexachiral design is shown to exhibit higher specific energy absorption capacity compared to the original design, as well as standard honeycomb structures.

Structural Health Monitoring of Large Structures

NASA Technical Reports Server (NTRS)

Kim, Hyoung M.; Bartkowicz, Theodore J.; Smith, Suzanne Weaver; Zimmerman, David C.

1994-01-01

This paper describes a damage detection and health monitoring method that was developed for large space structures using on-orbit modal identification. After evaluating several existing model refinement and model reduction/expansion techniques, a new approach was developed to identify the location and extent of structural damage with a limited number of measurements. A general area of structural damage is first identified and, subsequently, a specific damaged structural component is located. This approach takes advantage of two different model refinement methods (optimal-update and design sensitivity) and two different model size matching methods (model reduction and eigenvector expansion). Performance of the proposed damage detection approach was demonstrated with test data from two different laboratory truss structures. This space technology can also be applied to structural inspection of aircraft, offshore platforms, oil tankers, ridges, and buildings. In addition, its applications to model refinement will improve the design of structural systems such as automobiles and electronic packaging.

The HCMM system: Development and performance

NASA Technical Reports Server (NTRS)

Stuart, L. M., Jr.

1982-01-01

The structure and history of the heat capacity mapping mission program is reviewed and the spacecraft is described including engineering specifications, instrument design, data handling, and image characteristics.

Indigenous lunar construction materials

NASA Technical Reports Server (NTRS)

Rogers, Wayne; Sture, Stein

1991-01-01

The objectives are the following: to investigate the feasibility of the use of local lunar resources for construction of a lunar base structure; to develop a material processing method and integrate the method with design and construction of a pressurized habitation structure; to estimate specifications of the support equipment necessary for material processing and construction; and to provide parameters for systems models of lunar base constructions, supply, and operations. The topics are presented in viewgraph form and include the following: comparison of various lunar structures; guidelines for material processing methods; cast lunar regolith; examples of cast basalt components; cast regolith process; processing equipment; mechanical properties of cast basalt; material properties and structural design; and future work.

Metal stabilization of collagen and de novo designed mimetic peptides

PubMed Central

Parmar, Avanish S.; Xu, Fei; Pike, Douglas H.; Belure, Sandeep V.; Hasan, Nida F.; Drzewiecki, Kathryn E.; Shreiber, David I.; Nanda, Vikas

2017-01-01

We explore the design of metal binding sites to modulate triple-helix stability of collagen and collagen-mimetic peptides. Globular proteins commonly utilize metals to connect tertiary structural elements that are well separated in sequence, constraining structure and enhancing stability. It is more challenging to engineer structural metals into fibrous protein scaffolds, which lack the extensive tertiary contacts seen in globular proteins. In the collagen triple helix, the structural adjacency of the carboxy-termini of the three chains makes this region an attractive target for introducing metal binding sites. We engineered His3 sites based on structural modeling constraints into a series of designed homotrimeric and heterotrimeric peptides, assessing the capacity of metal binding to improve stability and in the case of heterotrimers, affect specificity of assembly. Notable enhancements in stability for both homo and heteromeric systems were observed upon addition of zinc(II) and several other metal ions only when all three histidine ligands were present. Metal binding affinities were consistent with the expected Irving-Williams series for imidazole. Unlike other metals tested, copper(II) also bound to peptides lacking histidine ligands. Acetylation of the peptide N-termini prevented copper binding, indicating proline backbone amide metal-coordination at this site. Copper similarly stabilized animal extracted Type I collagen in a metal specific fashion, highlighting the potential importance of metal homeostasis within the extracellular matrix. PMID:26225466

Finite element structural redesign by large admissible perturbations

NASA Technical Reports Server (NTRS)

Bernitsas, Michael M.; Beyko, E.; Rim, C. W.; Alzahabi, B.

1991-01-01

In structural redesign, two structural states are involved; the baseline (known) State S1 with unacceptable performance, and the objective (unknown) State S2 with given performance specifications. The difference between the two states in performance and design variables may be as high as 100 percent or more depending on the scale of the structure. A Perturbation Approach to Redesign (PAR) is presented to relate any two structural states S1 and S2 that are modeled by the same finite element model and represented by different values of the design variables. General perturbation equations are derived expressing implicitly the natural frequencies, dynamic modes, static deflections, static stresses, Euler buckling loads, and buckling modes of the objective S2 in terms of its performance specifications, and S1 data and Finite Element Analysis (FEA) results. Large Admissible Perturbation (LEAP) algorithms are implemented in code RESTRUCT to define the objective S2 incrementally without trial and error by postprocessing FEA results of S1 with no additional FEAs. Systematic numerical applications in redesign of a 10 element 48 degree of freedom (dof) beam, a 104 element 192 dof offshore tower, a 64 element 216 dof plate, and a 144 element 896 dof cylindrical shell show the accuracy, efficiency, and potential of PAR to find an objective state that may differ 100 percent from the baseline design.

Metal Stabilization of Collagen and de Novo Designed Mimetic Peptides.

PubMed

Parmar, Avanish S; Xu, Fei; Pike, Douglas H; Belure, Sandeep V; Hasan, Nida F; Drzewiecki, Kathryn E; Shreiber, David I; Nanda, Vikas

2015-08-18

We explore the design of metal binding sites to modulate triple-helix stability of collagen and collagen-mimetic peptides. Globular proteins commonly utilize metals to connect tertiary structural elements that are well separated in sequence, constraining structure and enhancing stability. It is more challenging to engineer structural metals into fibrous protein scaffolds, which lack the extensive tertiary contacts seen in globular proteins. In the collagen triple helix, the structural adjacency of the carboxy-termini of the three chains makes this region an attractive target for introducing metal binding sites. We engineered His3 sites based on structural modeling constraints into a series of designed homotrimeric and heterotrimeric peptides, assessing the capacity of metal binding to improve stability and in the case of heterotrimers, affect specificity of assembly. Notable enhancements in stability for both homo- and heteromeric systems were observed upon addition of zinc(II) and several other metal ions only when all three histidine ligands were present. Metal binding affinities were consistent with the expected Irving-Williams series for imidazole. Unlike other metals tested, copper(II) also bound to peptides lacking histidine ligands. Acetylation of the peptide N-termini prevented copper binding, indicating proline backbone amide metal-coordination at this site. Copper similarly stabilized animal extracted Type I collagen in a metal-specific fashion, highlighting the potential importance of metal homeostasis within the extracellular matrix.

The structural approach to shared knowledge: an application to engineering design teams.

PubMed

Avnet, Mark S; Weigel, Annalisa L

2013-06-01

We propose a methodology for analyzing shared knowledge in engineering design teams. Whereas prior work has focused on shared knowledge in small teams at a specific point in time, the model presented here is both scalable and dynamic. By quantifying team members' common views of design drivers, we build a network of shared mental models to reveal the structure of shared knowledge at a snapshot in time. Based on a structural comparison of networks at different points in time, a metric of change in shared knowledge is computed. Analysis of survey data from 12 conceptual space mission design sessions reveals a correlation between change in shared knowledge and each of several system attributes, including system development time, system mass, and technological maturity. From these results, we conclude that an early period of learning and consensus building could be beneficial to the design of engineered systems. Although we do not examine team performance directly, we demonstrate that shared knowledge is related to the technical design and thus provide a foundation for improving design products by incorporating the knowledge and thoughts of the engineering design team into the process.

Anchored plasticity opens doors for selective inhibitor design in nitric oxide synthase

PubMed Central

Garcin, Elsa D.; Arvai, Andrew S.; Rosenfeld, Robin J.; Kroeger, Matt D.; Crane, Brian R.; Andersson, Gunilla; Andrews, Glen; Hamley, Peter J.; Mallinder, Philip R.; Nicholls, David J.; St-Gallay, Stephen A.; Tinker, Alan C.; Gensmantel, Nigel P.; Mete, Antonio; Cheshire, David R.; Connolly, Stephen; Stuehr, Dennis J.; Åberg, Anders; Wallace, Alan V.; Tainer, John A.; Getzoff, Elizabeth D.

2008-01-01

Nitric oxide synthase (NOS) enzymes synthesize nitric oxide, a signal for vasodilatation and neurotransmission at low levels, and a defensive cytotoxin at higher levels. The high active-site conservation among all three NOS isozymes hinders the design of selective NOS inhibitors to treat inflammation, arthritis, stroke, septic shock, and cancer. Our structural and mutagenesis results identified an isozyme-specific induced-fit binding mode linking a cascade of conformational changes to a novel specificity pocket. Plasticity of an isozyme-specific triad of distant second- and third-shell residues modulates conformational changes of invariant first-shell residues to determine inhibitor selectivity. To design potent and selective NOS inhibitors, we developed the anchored plasticity approach: anchor an inhibitor core in a conserved binding pocket, then extend rigid bulky substituents towards remote specificity pockets, accessible upon conformational changes of flexible residues. This approach exemplifies general principles for the design of selective enzyme inhibitors that overcome strong active-site conservation. PMID:18849972

Rapid search for tertiary fragments reveals protein sequence–structure relationships

PubMed Central

Zhou, Jianfu; Grigoryan, Gevorg

2015-01-01

Finding backbone substructures from the Protein Data Bank that match an arbitrary query structural motif, composed of multiple disjoint segments, is a problem of growing relevance in structure prediction and protein design. Although numerous protein structure search approaches have been proposed, methods that address this specific task without additional restrictions and on practical time scales are generally lacking. Here, we propose a solution, dubbed MASTER, that is both rapid, enabling searches over the Protein Data Bank in a matter of seconds, and provably correct, finding all matches below a user-specified root-mean-square deviation cutoff. We show that despite the potentially exponential time complexity of the problem, running times in practice are modest even for queries with many segments. The ability to explore naturally plausible structural and sequence variations around a given motif has the potential to synthesize its design principles in an automated manner; so we go on to illustrate the utility of MASTER to protein structural biology. We demonstrate its capacity to rapidly establish structure–sequence relationships, uncover the native designability landscapes of tertiary structural motifs, identify structural signatures of binding, and automatically rewire protein topologies. Given the broad utility of protein tertiary fragment searches, we hope that providing MASTER in an open-source format will enable novel advances in understanding, predicting, and designing protein structure. PMID:25420575

Image-Based Patient-Specific Ventricle Models with Fluid-Structure Interaction for Cardiac Function Assessment and Surgical Design Optimization

PubMed Central

Tang, Dalin; Yang, Chun; Geva, Tal; del Nido, Pedro J.

2010-01-01

Recent advances in medical imaging technology and computational modeling techniques are making it possible that patient-specific computational ventricle models be constructed and used to test surgical hypotheses and replace empirical and often risky clinical experimentation to examine the efficiency and suitability of various reconstructive procedures in diseased hearts. In this paper, we provide a brief review on recent development in ventricle modeling and its potential application in surgical planning and management of tetralogy of Fallot (ToF) patients. Aspects of data acquisition, model selection and construction, tissue material properties, ventricle layer structure and tissue fiber orientations, pressure condition, model validation and virtual surgery procedures (changing patient-specific ventricle data and perform computer simulation) were reviewed. Results from a case study using patient-specific cardiac magnetic resonance (CMR) imaging and right/left ventricle and patch (RV/LV/Patch) combination model with fluid-structure interactions (FSI) were reported. The models were used to evaluate and optimize human pulmonary valve replacement/insertion (PVR) surgical procedure and patch design and test a surgical hypothesis that PVR with small patch and aggressive scar tissue trimming in PVR surgery may lead to improved recovery of RV function and reduced stress/strain conditions in the patch area. PMID:21344066

Crystal structures of mammalian glutamine synthetases illustrate substrate-induced conformational changes and provide opportunities for drug and herbicide design.

PubMed

Krajewski, Wojciech W; Collins, Ruairi; Holmberg-Schiavone, Lovisa; Jones, T Alwyn; Karlberg, Tobias; Mowbray, Sherry L

2008-01-04

Glutamine synthetase (GS) catalyzes the ligation of glutamate and ammonia to form glutamine, with concomitant hydrolysis of ATP. In mammals, the activity eliminates cytotoxic ammonia, at the same time converting neurotoxic glutamate to harmless glutamine; there are a number of links between changes in GS activity and neurodegenerative disorders, such as Alzheimer's disease. In plants, because of its importance in the assimilation and re-assimilation of ammonia, the enzyme is a target of some herbicides. GS is also a central component of bacterial nitrogen metabolism and a potential drug target. Previous studies had investigated the structures of bacterial and plant GSs. In the present publication, we report the first structures of mammalian GSs. The apo form of the canine enzyme was solved by molecular replacement and refined at a resolution of 3 A. Two structures of human glutamine synthetase represent complexes with: a) phosphate, ADP, and manganese, and b) a phosphorylated form of the inhibitor methionine sulfoximine, ADP and manganese; these structures were refined to resolutions of 2.05 A and 2.6 A, respectively. Loop movements near the active site generate more closed forms of the eukaryotic enzymes when substrates are bound; the largest changes are associated with the binding of the nucleotide. Comparisons with earlier structures provide a basis for the design of drugs that are specifically directed at either human or bacterial enzymes. The site of binding the amino acid substrate is highly conserved in bacterial and eukaryotic GSs, whereas the nucleotide binding site varies to a much larger degree. Thus, the latter site offers the best target for specific drug design. Differences between mammalian and plant enzymes are much more subtle, suggesting that herbicides targeting GS must be designed with caution.

Predictive Bcl-2 Family Binding Models Rooted in Experiment or Structure

PubMed Central

DeBartolo, Joe; Dutta, Sanjib; Reich, Lothar; Keating, Amy E.

2013-01-01

Proteins of the Bcl-2 family either enhance or suppress programmed cell death and are centrally involved in cancer development and resistance to chemotherapy. BH3 (Bcl-2 homology 3)-only Bcl-2 proteins promote cell death by docking an α-helix into a hydrophobic groove on the surface of one or more of five pro-survival Bcl-2 receptor proteins. There is high structural homology within the pro-death and pro-survival families, yet a high degree of interaction specificity is nevertheless encoded, posing an interesting and important molecular recognition problem. Understanding protein features that dictate Bcl-2 interaction specificity is critical for designing peptide-based cancer therapeutics and diagnostics. In this study, we present peptide SPOT arrays and deep sequencing data from yeast display screening experiments that significantly expand the BH3 sequence space that has been experimentally tested for interaction with five human anti-apoptotic receptors. These data provide rich information about the determinants of Bcl-2 family specificity. To interpret and use the information, we constructed two simple data-based models that can predict affinity and specificity when evaluated on independent data sets within a limited sequence space. We also constructed a novel structure-based statistical potential, called STATIUM, which is remarkably good at predicting Bcl-2 affinity and specificity, especially considering it is not trained on experimental data. We compare the performance of our three models to each other and to alternative structure-based methods and discuss how such tools can guide prediction and design of new Bcl-2 family complexes. PMID:22617328

NASA software specification and evaluation system: Software verification/validation techniques

NASA Technical Reports Server (NTRS)

1977-01-01

NASA software requirement specifications were used in the development of a system for validating and verifying computer programs. The software specification and evaluation system (SSES) provides for the effective and efficient specification, implementation, and testing of computer software programs. The system as implemented will produce structured FORTRAN or ANSI FORTRAN programs, but the principles upon which SSES is designed allow it to be easily adapted to other high order languages.

Structural Brain Atlases: Design, Rationale, and Applications in Normal and Pathological Cohorts

PubMed Central

Mandal, Pravat K.; Mahajan, Rashima; Dinov, Ivo D.

2015-01-01

Structural magnetic resonance imaging (MRI) provides anatomical information about the brain in healthy as well as in diseased conditions. On the other hand, functional MRI (fMRI) provides information on the brain activity during performance of a specific task. Analysis of fMRI data requires the registration of the data to a reference brain template in order to identify the activated brain regions. Brain templates also find application in other neuroimaging modalities, such as diffusion tensor imaging and multi-voxel spectroscopy. Further, there are certain differences (e.g., brain shape and size) in the brains of populations of different origin and during diseased conditions like in Alzheimer’s disease (AD), population and disease-specific brain templates may be considered crucial for accurate registration and subsequent analysis of fMRI as well as other neuroimaging data. This manuscript provides a comprehensive review of the history, construction and application of brain atlases. A chronological outline of the development of brain template design, starting from the Talairach and Tournoux atlas to the Chinese brain template (to date), along with their respective detailed construction protocols provides the backdrop to this manuscript. The manuscript also provides the automated workflow-based protocol for designing a population-specific brain atlas from structural MRI data using LONI Pipeline graphical workflow environment. We conclude by discussing the scope of brain templates as a research tool and their application in various neuroimaging modalities. PMID:22647262

The type of carbohydrates specifically selects microbial community structures and fermentation patterns.

PubMed

Chatellard, Lucile; Trably, Eric; Carrère, Hélène

2016-12-01

The impact on dark fermentation of seven carbohydrates as model substrates of lignocellulosic fractions (glucose, cellobiose, microcrystalline cellulose, arabinose, xylose, xylan and wheat straw) was investigated. Metabolic patterns and bacterial communities were characterized at the end of batch tests inoculated with manure digestate. It was found that hydrogen production was linked to the sugar type (pentose or hexose) and the degree of polymerisation. Hexoses produced less hydrogen, with a specific selection of lactate-producing bacterial community structures. Maximal hydrogen production was five times higher on pentose-based substrates, with specific bacterial community structures producing acetate and butyrate as main metabolites. Low hydrogen amounts accumulated from complex sugars (cellulose, xylan and wheat straw). A relatively high proportion of the reads was affiliated to Ruminococcaceae suggesting an efficient hydrolytic activity. Knowing that the bacterial community structure is very specific to a particular substrate offers new possibilities to design more efficient H 2 -producing biological systems. Copyright © 2016 Elsevier Ltd. All rights reserved.

Displacement Based Multilevel Structural Optimization

NASA Technical Reports Server (NTRS)

Sobieszezanski-Sobieski, J.; Striz, A. G.

1996-01-01

In the complex environment of true multidisciplinary design optimization (MDO), efficiency is one of the most desirable attributes of any approach. In the present research, a new and highly efficient methodology for the MDO subset of structural optimization is proposed and detailed, i.e., for the weight minimization of a given structure under size, strength, and displacement constraints. Specifically, finite element based multilevel optimization of structures is performed. In the system level optimization, the design variables are the coefficients of assumed polynomially based global displacement functions, and the load unbalance resulting from the solution of the global stiffness equations is minimized. In the subsystems level optimizations, the weight of each element is minimized under the action of stress constraints, with the cross sectional dimensions as design variables. The approach is expected to prove very efficient since the design task is broken down into a large number of small and efficient subtasks, each with a small number of variables, which are amenable to parallel computing.

Interactions of a designed peptide with lipopolysaccharide: Bound conformation and anti-endotoxic activity

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

Bhunia, Anirban; Chua, Geok Lin; Domadia, Prerna N.

Designed peptides that would selectively interact with lipopolysaccharide (LPS) or endotoxin and fold into specific conformations could serve as important scaffolds toward the development of antisepsis compounds. Here, we describe solution structure of a designed amphipathic peptide, H{sub 2}N-YVKLWRMIKFIR-CONH{sub 2} (YW12D) in complex with endotoxin as determined by transferred nuclear Overhauser effect spectroscopy. The conformation of the isolated peptide is highly flexible, but undergoes a dramatic structural stabilization in the presence of LPS. Structure calculations reveal that the peptide presents two amphipathic surfaces in its bound state to LPS whereby each surface is characterized by two positive charges and amore » number of aromatic and/or aliphatic residues. ITC data suggests that peptide interacts with two molecules of lipid A. In activity assays, YW12D exhibits neutralization of LPS toxicity with very little hemolysis of red blood cells. Structural and functional properties of YW12D would be applicable in designing low molecular weight non-toxic antisepsis molecules.« less

The use of subjective expert opinions in cost optimum design of aerospace structures. [probabilistic failure models

NASA Technical Reports Server (NTRS)

Thomas, J. M.; Hanagud, S.

1975-01-01

The results of two questionnaires sent to engineering experts are statistically analyzed and compared with objective data from Saturn V design and testing. Engineers were asked how likely it was for structural failure to occur at load increments above and below analysts' stress limit predictions. They were requested to estimate the relative probabilities of different failure causes, and of failure at each load increment given a specific cause. Three mathematical models are constructed based on the experts' assessment of causes. The experts' overall assessment of prediction strength fits the Saturn V data better than the models do, but a model test option (T-3) based on the overall assessment gives more design change likelihood to overstrength structures than does an older standard test option. T-3 compares unfavorably with the standard option in a cost optimum structural design problem. The report reflects a need for subjective data when objective data are unavailable.

Ultra-low-mass flexible planar solar arrays using 50-micron-thick solar cells

NASA Technical Reports Server (NTRS)

Costogue, E. N.; Rayl, G.

1978-01-01

A conceptual design study has been completed which has shown the feasibility of ultra-low-mass planar solar arrays with specific power of 200 watts/kilogram. The beginning of life (BOL) power output of the array designs would be 10 kW at 1 astronomical unit (AU) and a 55C deg operating temperature. Two designs were studied: a retractable rollout design and a non-retractable fold-out. The designs employed a flexible low-mass blanket and low-mass structures. The blanket utilized 2 x 2 cm high-efficiency (13.5% at 28C deg AM0), ultra-thin (50 micron), silicon solar cells protected by thin (75 micron) plastic encapsulants. The structural design utilized the 'V'-stiffened approach which allows a lower mass boom to be used. In conjunction with the conceptual design, modules using the thin cells and plastic encapsulant were designed and fabricated.

Representation of bidirectional ground motions for design spectra in building codes

USGS Publications Warehouse

Stewart, Jonathan P.; Abrahamson, Norman A.; Atkinson, Gail M.; Beker, Jack W.; Boore, David M.; Bozorgnia, Yousef; Campbell, Kenneth W.; Comartin, Craig D.; Idriss, I.M.; Lew, Marshall; Mehrain, Michael; Moehle, Jack P.; Naeim, Farzad; Sabol, Thomas A.

2011-01-01

The 2009 NEHRP Provisions modified the definition of horizontal ground motion from the geometric mean of spectral accelerations for two components to the peak response of a single lumped mass oscillator regardless of direction. These maximum-direction (MD) ground motions operate under the assumption that the dynamic properties of the structure (e.g., stiffness, strength) are identical in all directions. This assumption may be true for some in-plan symmetric structures, however, the response of most structures is dominated by modes of vibration along specific axes (e.g., longitudinal and transverse axes in a building), and often the dynamic properties (especially stiffness) along those axes are distinct. In order to achieve structural designs consistent with the collapse risk level given in the NEHRP documents, we argue that design spectra should be compatible with expected levels of ground motion along those principal response axes. The use of MD ground motions effectively assumes that the azimuth of maximum ground motion coincides with the directions of principal structural response. Because this is unlikely, design ground motions have lower probability of occurrence than intended, with significant societal costs. We recommend adjustments to make design ground motions compatible with target risk levels.

META-X Design Flow Tools

DTIC Science & Technology

2013-04-01

Forces can be computed at specific angular positions, and geometrical parameters can be evaluated. Much higher resolution models are required, along...composition engines (C#, C++, Python, Java ) Desert operates on the CyPhy model, converting from a design space alternative structure to a set of design...consists of scripts to execute dymola, post-processing of results to create metrics, and general management of the job sequence. An earlier version created

Adaptive wing structures

NASA Astrophysics Data System (ADS)

Reed, John L., Jr.; Hemmelgarn, Christopher D.; Pelley, Bryan M.; Havens, Ernie

2005-05-01

Cornerstone Research Group, Inc. (CRG) is developing a unique adaptive wing structure intended to enhance the capability of loitering Unmanned Air Vehicles (UAVs). In order to tailor the wing design to a specific application, CRG has developed a wing structure capable of morphing in chord and increasing planform area by 80 percent. With these features, aircraft will be capable of optimizing their flight efficiency throughout the entire mission profile. The key benefit from this morphing design is increased maneuverability, resulting in improved effectiveness over the current design. During the development process CRG has overcome several challenges in the design of such a structure while incorporating advanced materials capable of maintaining aerodynamic shape and transferring aerodynamic loads while enabling crucial changes in planform shape. To overcome some of these challenges, CRG is working on integration of their shape memory polymer materials into the wing skin to enable seamless morphing. This paper will address the challenges associated with the development of a morphing aerospace structure capable of such large shape change, the materials necessary for enabling morphing capabilities, and the current status of the morphing program within CRG.

Evolutionary Optimization of a Geometrically Refined Truss

NASA Technical Reports Server (NTRS)

Hull, P. V.; Tinker, M. L.; Dozier, G. V.

2007-01-01

Structural optimization is a field of research that has experienced noteworthy growth for many years. Researchers in this area have developed optimization tools to successfully design and model structures, typically minimizing mass while maintaining certain deflection and stress constraints. Numerous optimization studies have been performed to minimize mass, deflection, and stress on a benchmark cantilever truss problem. Predominantly traditional optimization theory is applied to this problem. The cross-sectional area of each member is optimized to minimize the aforementioned objectives. This Technical Publication (TP) presents a structural optimization technique that has been previously applied to compliant mechanism design. This technique demonstrates a method that combines topology optimization, geometric refinement, finite element analysis, and two forms of evolutionary computation: genetic algorithms and differential evolution to successfully optimize a benchmark structural optimization problem. A nontraditional solution to the benchmark problem is presented in this TP, specifically a geometrically refined topological solution. The design process begins with an alternate control mesh formulation, multilevel geometric smoothing operation, and an elastostatic structural analysis. The design process is wrapped in an evolutionary computing optimization toolset.

Enriching peptide libraries for binding affinity and specificity through computationally directed library design

PubMed Central

Foight, Glenna Wink; Chen, T. Scott; Richman, Daniel; Keating, Amy E.

2017-01-01

Peptide reagents with high affinity or specificity for their target protein interaction partner are of utility for many important applications. Optimization of peptide binding by screening large libraries is a proven and powerful approach. Libraries designed to be enriched in peptide sequences that are predicted to have desired affinity or specificity characteristics are more likely to yield success than random mutagenesis. We present a library optimization method in which the choice of amino acids to encode at each peptide position can be guided by available experimental data or structure-based predictions. We discuss how to use analysis of predicted library performance to inform rounds of library design. Finally, we include protocols for more complex library design procedures that consider the chemical diversity of the amino acids at each peptide position and optimize a library score based on a user-specified input model. PMID:28236241

Enriching Peptide Libraries for Binding Affinity and Specificity Through Computationally Directed Library Design.

PubMed

Foight, Glenna Wink; Chen, T Scott; Richman, Daniel; Keating, Amy E

2017-01-01

Peptide reagents with high affinity or specificity for their target protein interaction partner are of utility for many important applications. Optimization of peptide binding by screening large libraries is a proven and powerful approach. Libraries designed to be enriched in peptide sequences that are predicted to have desired affinity or specificity characteristics are more likely to yield success than random mutagenesis. We present a library optimization method in which the choice of amino acids to encode at each peptide position can be guided by available experimental data or structure-based predictions. We discuss how to use analysis of predicted library performance to inform rounds of library design. Finally, we include protocols for more complex library design procedures that consider the chemical diversity of the amino acids at each peptide position and optimize a library score based on a user-specified input model.

Closing the door on flaviviruses: entry as a target for antiviral drug design.

PubMed

Perera, Rushika; Khaliq, Mansoora; Kuhn, Richard J

2008-10-01

With the emergence and rapid spread of West Nile virus in the United States since 1999, and the 50-100 million infections per year caused by dengue virus globally, the threat of flaviviruses as re-emerging human pathogens has become a reality. To support the efforts that are currently being pursued to develop effective vaccines against these viruses, researchers are also actively pursuing the development of small molecule compounds that target various aspects of the virus life cycle. Recent advances in the structural characterization of the flaviviruses have provided a strong foundation towards these efforts. These studies have provided the pseudo-atomic structures of virions from several members of the genus as well as atomic resolution structures of several viral proteins. Most importantly, these studies have highlighted specific structural rearrangements that occur within the virion that are necessary for the virus to complete its life cycle. These rearrangements occur when the virus must transition from immature, to mature, to fusion-active states and rely heavily on the conformational flexibility of the envelope (E) protein that forms the outer glycoprotein shell of the virus. Analysis of these conformational changes can suggest promising targets for structure-based antiviral design. For instance, by targeting the flexibility of the E protein, it might be possible to inhibit required rearrangements of this protein and trap the virus in a specific state. This would interfere with a productive flaviviral infection. This review presents a structural perspective of the flavivirus life cycle and focuses on the role of the E protein as an opportune target for structure-based antiviral drug design.

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.

RNA Structure Design Improves Activity and Specificity of trans-Splicing-Triggered Cell Death in a Suicide Gene Therapy Approach.

PubMed

Poddar, Sushmita; Loh, Pei She; Ooi, Zi Hao; Osman, Farhana; Eul, Joachim; Patzel, Volker

2018-06-01

Spliceosome-mediated RNA trans-splicing enables correction or labeling of pre-mRNA, but therapeutic applications are hampered by issues related to the activity and target specificity of trans-splicing RNA (tsRNA). We employed computational RNA structure design to improve both on-target activity and specificity of tsRNA in a herpes simplex virus thymidine kinase/ganciclovir suicide gene therapy approach targeting alpha fetoprotein (AFP), a marker of hepatocellular carcinoma (HCC) or human papillomavirus type 16 (HPV-16) pre-mRNA. While unstructured, mismatched target binding domains significantly improved 3' exon replacement (3'ER), 5' exon replacement (5'ER) correlated with the thermodynamic stability of the tsRNA 3' end. Alternative on-target trans-splicing was found to be a prevalent event. The specificity of trans-splicing with the intended target splice site was improved 10-fold by designing tsRNA that harbors secondary target binding domains shielding alternative on-target and blinding off-target splicing events. Such rationally designed suicide RNAs efficiently triggered death of HPV-16-transduced or hepatoblastoma-derived human tissue culture cells without evidence for off-target cell killing. Highest cell death activities were observed with novel dual-targeting tsRNAs programmed for trans-splicing toward AFP and a second HCC pre-mRNA biomarker. Our observations suggest trans-splicing represents a promising approach to suicide gene therapy. Copyright © 2018 The Author(s). Published by Elsevier Inc. All rights reserved.

Rational design to improve thermostability and specific activity of the truncated Fibrobacter succinogenes 1,3-1,4-β-D-glucanase.

PubMed

Huang, Jian-Wen; Cheng, Ya-Shan; Ko, Tzu-Ping; Lin, Cheng-Yen; Lai, Hui-Lin; Chen, Chun-Chi; Ma, Yanhe; Zheng, Yingying; Huang, Chun-Hsiang; Zou, Peijian; Liu, Je-Ruei; Guo, Rey-Ting

2012-04-01

1,3-1,4-β-D-Glucanase has been widely used as a feed additive to help non-ruminant animals digest plant fibers, with potential in increasing nutrition turnover rate and reducing sanitary problems. Engineering of enzymes for better thermostability is of great importance because it not only can broaden their industrial applications, but also facilitate exploring the mechanism of enzyme stability from structural point of view. To obtain enzyme with higher thermostability and specific activity, structure-based rational design was carried out in this study. Eleven mutants of Fibrobacter succinogenes 1,3-1,4-β-D-glucanase were constructed in attempt to improve the enzyme properties. In particular, the crude proteins expressed in Pichia pastoris were examined firstly to ensure that the protein productions meet the need for industrial fermentation. The crude protein of V18Y mutant showed a 2 °C increment of Tm and W203Y showed ∼30% increment of the specific activity. To further investigate the structure-function relationship, some mutants were expressed and purified from P. pastoris and Escherichia coli. Notably, the specific activity of purified W203Y which was expressed in E. coli was 63% higher than the wild-type protein. The double mutant V18Y/W203Y showed the same increments of Tm and specific activity as the single mutants did. When expressed and purified from E. coli, V18Y/W203Y showed similar pattern of thermostability increment and 75% higher specific activity. Furthermore, the apo-form and substrate complex structures of V18Y/W203Y were solved by X-ray crystallography. Analyzing protein structure of V18Y/W203Y helps elucidate how the mutations could enhance the protein stability and enzyme activity.

Method and structure for skewed block-cyclic distribution of lower-dimensional data arrays in higher-dimensional processor grids

DOEpatents

Chatterjee, Siddhartha [Yorktown Heights, NY; Gunnels, John A [Brewster, NY

2011-11-08

A method and structure of distributing elements of an array of data in a computer memory to a specific processor of a multi-dimensional mesh of parallel processors includes designating a distribution of elements of at least a portion of the array to be executed by specific processors in the multi-dimensional mesh of parallel processors. The pattern of the designating includes a cyclical repetitive pattern of the parallel processor mesh, as modified to have a skew in at least one dimension so that both a row of data in the array and a column of data in the array map to respective contiguous groupings of the processors such that a dimension of the contiguous groupings is greater than one.

Designing collective behavior in a termite-inspired robot construction team.

PubMed

Werfel, Justin; Petersen, Kirstin; Nagpal, Radhika

2014-02-14

Complex systems are characterized by many independent components whose low-level actions produce collective high-level results. Predicting high-level results given low-level rules is a key open challenge; the inverse problem, finding low-level rules that give specific outcomes, is in general still less understood. We present a multi-agent construction system inspired by mound-building termites, solving such an inverse problem. A user specifies a desired structure, and the system automatically generates low-level rules for independent climbing robots that guarantee production of that structure. Robots use only local sensing and coordinate their activity via the shared environment. We demonstrate the approach via a physical realization with three autonomous climbing robots limited to onboard sensing. This work advances the aim of engineering complex systems that achieve specific human-designed goals.

Druggable pockets and binding site centric chemical space: a paradigm shift in drug discovery.

PubMed

Pérot, Stéphanie; Sperandio, Olivier; Miteva, Maria A; Camproux, Anne-Claude; Villoutreix, Bruno O

2010-08-01

Detection, comparison and analyses of binding pockets are pivotal to structure-based drug design endeavors, from hit identification, screening of exosites and de-orphanization of protein functions to the anticipation of specific and non-specific binding to off- and anti-targets. Here, we analyze protein-ligand complexes and discuss methods that assist binding site identification, prediction of druggability and binding site comparison. The full potential of pockets is yet to be harnessed, and we envision that better understanding of the pocket space will have far-reaching implications in the field of drug discovery, such as the design of pocket-specific compound libraries and scoring functions.

Designing Industrial Networks Using Ecological Food Web Metrics.

PubMed

Layton, Astrid; Bras, Bert; Weissburg, Marc

2016-10-18

Biologically Inspired Design (biomimicry) and Industrial Ecology both look to natural systems to enhance the sustainability and performance of engineered products, systems and industries. Bioinspired design (BID) traditionally has focused on a unit operation and single product level. In contrast, this paper describes how principles of network organization derived from analysis of ecosystem properties can be applied to industrial system networks. Specifically, this paper examines the applicability of particular food web matrix properties as design rules for economically and biologically sustainable industrial networks, using an optimization model developed for a carpet recycling network. Carpet recycling network designs based on traditional cost and emissions based optimization are compared to designs obtained using optimizations based solely on ecological food web metrics. The analysis suggests that networks optimized using food web metrics also were superior from a traditional cost and emissions perspective; correlations between optimization using ecological metrics and traditional optimization ranged generally from 0.70 to 0.96, with flow-based metrics being superior to structural parameters. Four structural food parameters provided correlations nearly the same as that obtained using all structural parameters, but individual structural parameters provided much less satisfactory correlations. The analysis indicates that bioinspired design principles from ecosystems can lead to both environmentally and economically sustainable industrial resource networks, and represent guidelines for designing sustainable industry networks.

Computational design of an endo-1,4-[beta]-xylanase ligand binding site

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

Morin, Andrew; Kaufmann, Kristian W.; Fortenberry, Carie

2012-09-05

The field of computational protein design has experienced important recent success. However, the de novo computational design of high-affinity protein-ligand interfaces is still largely an open challenge. Using the Rosetta program, we attempted the in silico design of a high-affinity protein interface to a small peptide ligand. We chose the thermophilic endo-1,4-{beta}-xylanase from Nonomuraea flexuosa as the protein scaffold on which to perform our designs. Over the course of the study, 12 proteins derived from this scaffold were produced and assayed for binding to the target ligand. Unfortunately, none of the designed proteins displayed evidence of high-affinity binding. Structural characterizationmore » of four designed proteins revealed that although the predicted structure of the protein model was highly accurate, this structural accuracy did not translate into accurate prediction of binding affinity. Crystallographic analyses indicate that the lack of binding affinity is possibly due to unaccounted for protein dynamics in the 'thumb' region of our design scaffold intrinsic to the family 11 {beta}-xylanase fold. Further computational analysis revealed two specific, single amino acid substitutions responsible for an observed change in backbone conformation, and decreased dynamic stability of the catalytic cleft. These findings offer new insight into the dynamic and structural determinants of the {beta}-xylanase proteins.« less

Enhanced protective role in materials with gradient structural orientations: Lessons from Nature.

PubMed

Liu, Zengqian; Zhu, Yankun; Jiao, Da; Weng, Zhaoyong; Zhang, Zhefeng; Ritchie, Robert O

2016-10-15

Living organisms are adept at resisting contact deformation and damage by assembling protective surfaces with spatially varied mechanical properties, i.e., by creating functionally graded materials. Such gradients, together with multiple length-scale hierarchical structures, represent the two prime characteristics of many biological materials to be translated into engineering design. Here, we examine one design motif from a variety of biological tissues and materials where site-specific mechanical properties are generated for enhanced protection by adopting gradients in structural orientation over multiple length-scales, without manipulation of composition or microstructural dimension. Quantitative correlations are established between the structural orientations and local mechanical properties, such as stiffness, strength and fracture resistance; based on such gradients, the underlying mechanisms for the enhanced protective role of these materials are clarified. Theoretical analysis is presented and corroborated through numerical simulations of the indentation behavior of composites with distinct orientations. The design strategy of such bioinspired gradients is outlined in terms of the geometry of constituents. This study may offer a feasible approach towards generating functionally graded mechanical properties in synthetic materials for improved contact damage resistance. Living organisms are adept at resisting contact damage by assembling protective surfaces with spatially varied mechanical properties, i.e., by creating functionally-graded materials. Such gradients, together with multiple length-scale hierarchical structures, represent the prime characteristics of many biological materials. Here, we examine one design motif from a variety of biological tissues where site-specific mechanical properties are generated for enhanced protection by adopting gradients in structural orientation at multiple length-scales, without changes in composition or microstructural dimension. The design strategy of such bioinspired gradients is outlined in terms of the geometry of constituents. This study may offer a feasible approach towards generating functionally-graded mechanical properties in synthetic materials for improved damage resistance. Published by Elsevier Ltd.

English for Specific Purposes: Negotiating Needs, Possibilities, and Promises

ERIC Educational Resources Information Center

Salas, Spencer; Mercado, Leonardo A.; Ouedraogo, Lynn Hanson; Musetti, Bernadette

2013-01-01

The authors espouse the need for negotiation in designing and delivering English for Specific Purposes (ESP) programs. Such negotiations take into account learners' needs as well as structural limitations of the context and candid assessment of ESP providers. The article explores lessons from the field and the importance of needs analysis.

Development of Lightweight Material Composites to Insulate Cryogenic Tanks for 30-Day Storage in Outer Space

NASA Technical Reports Server (NTRS)

Krause, D. R.

1972-01-01

A conceptual design was developed for an MLI system which will meet the design constraints of an ILRV used for 7- to 30-day missions. The ten tasks are briefly described: (1) material survey and procurement, material property tests, and selection of composites to be considered; (2) definition of environmental parameters and tooling requirements, and thermal and structural design verification test definition; (3) definition of tanks and associated hardware to be used, and definition of MLI concepts to be considered; (4) thermal analyses, including purge, evacuation, and reentry repressurization analyses; (5) structural analyses (6) thermal degradation tests of composite and structural tests of fastener; (7) selection of MLI materials and system; (8) definition of a conceptual MLI system design; (9) evaluation of nondestructive inspection techniques and definition of procedures for repair of damaged areas; and (10) preparation of preliminary specifications.

ADVANCED SEISMIC BASE ISOLATION METHODS FOR MODULAR REACTORS

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

E. Blanford; E. Keldrauk; M. Laufer

2010-09-20

Advanced technologies for structural design and construction have the potential for major impact not only on nuclear power plant construction time and cost, but also on the design process and on the safety, security and reliability of next generation of nuclear power plants. In future Generation IV (Gen IV) reactors, structural and seismic design should be much more closely integrated with the design of nuclear and industrial safety systems, physical security systems, and international safeguards systems. Overall reliability will be increased, through the use of replaceable and modular equipment, and through design to facilitate on-line monitoring, in-service inspection, maintenance, replacement,more » and decommissioning. Economics will also receive high design priority, through integrated engineering efforts to optimize building arrangements to minimize building heights and footprints. Finally, the licensing approach will be transformed by becoming increasingly performance based and technology neutral, using best-estimate simulation methods with uncertainty and margin quantification. In this context, two structural engineering technologies, seismic base isolation and modular steel-plate/concrete composite structural walls, are investigated. These technologies have major potential to (1) enable standardized reactor designs to be deployed across a wider range of sites, (2) reduce the impact of uncertainties related to site-specific seismic conditions, and (3) alleviate reactor equipment qualification requirements. For Gen IV reactors the potential for deliberate crashes of large aircraft must also be considered in design. This report concludes that base-isolated structures should be decoupled from the reactor external event exclusion system. As an example, a scoping analysis is performed for a rectangular, decoupled external event shell designed as a grillage. This report also reviews modular construction technology, particularly steel-plate/concrete construction using factory prefabricated structural modules, for application to external event shell and base isolated structures.« less

Librarians as Interior Designers: The Icing on the Cake (Profile of a Community College LRC: Palomar College).

ERIC Educational Resources Information Center

Arnsan, Dan

1985-01-01

Describes how staff at Palomar College Library participated in planning the interior of the library building in areas such as designing the floor plans, writing furniture specifications, choosing colors, and making structural changes in the facility. Offers advice for other librarians participating in building projects. (DMM)

The PCP SYS IV Management System: Educational Overview.

ERIC Educational Resources Information Center

Siegel, Martin A.; Davis, Dennis M.

This paper describes the structure and function of the SYS IV PLATO Curriculum Project's (PCP) computer-based management system and justifies the system design. A consideration of features most critical in the design of management systems provides the context for a discussion of specific SYS IV features, which include its ability to deliver any…

Different Versions of the Same Lesson Plan: Implications on the Lesson Design

ERIC Educational Resources Information Center

Greenlees, Jane; Patahuddin, Sitti Maesuri; Lowrie, Tom

2014-01-01

The World Bank 2007 TIMSS Video Study provided a distinctive insight into the practices of the Indonesian classroom and identified key strengths and weaknesses of current teaching. This investigation considered this evidence in the development of a structured lesson design that specifically addressed the instructional practices of the teaching and…

Using a Simple Contest to Illustrate Mechanism Design

ERIC Educational Resources Information Center

Blackwell, Calvin

2011-01-01

This article describes a simple classroom activity that illustrates how economic theory can be used for mechanism design. The rules for a set of contests are presented; the results typically obtained from these contests illustrate how the prize structure can be manipulated in order to produce a particular outcome. Specifically, this activity is…

State of the Art Methodology for the Design and Analysis of Future Large Scale Evaluations: A Selective Examination.

ERIC Educational Resources Information Center

Burstein, Leigh

Two specific methods of analysis in large-scale evaluations are considered: structural equation modeling and selection modeling/analysis of non-equivalent control group designs. Their utility in large-scale educational program evaluation is discussed. The examination of these methodological developments indicates how people (evaluators,…

Dynamics explorer: Interface definition study, volume 1

NASA Technical Reports Server (NTRS)

1978-01-01

Work done in response to the work statement wherein a specific deliverable was not identified but where design and analysis tasks were identified is reported. The summary and baseline change list is included along with design notes for the spacecraft system, thermal subsystem, power subsystem, communications subsystem, plasma wave instrument interface definition, and the structure.

Special Education Facilities: Schools and Playgrounds for Trainable Mentally Handicapped Children.

ERIC Educational Resources Information Center

Ontario Dept. of Education, Toronto. School Planning and Building Research Section.

Intended to assist school boards in planning educational facilities for trainable mentally retarded children, the booklet contains designs illustrating both the general structure and specific room arrangements for various sizes of school and various age groups. The designs show small, self-contained schools where mobility in the grouping of…

Math Problems for Water Quality Control Personnel, Instructor's Manual. Second Edition.

ERIC Educational Resources Information Center

Delvecchio, Fred; Brutsch, Gloria

This document is the instructor's manual for a course in mathematics for water quality control personnel. It is designed so a program may be designed for a specific facility. The problem structures are arranged alphabetically by treatment process. Charts, graphs and/or drawings representing familiar data forms contain the necessary information to…

33 CFR 320.4 - General policies for evaluating permit applications.

Code of Federal Regulations, 2012 CFR

2012-07-01

... specific factor may be given great weight on one proposal, while it may not be present or as important on... will ask the Governor to express his views or to designate one state agency to represent the official... are designed for safety, non-Federal applicants may be required to demonstrate that the structures...

33 CFR 320.4 - General policies for evaluating permit applications.

Code of Federal Regulations, 2013 CFR

2013-07-01

... specific factor may be given great weight on one proposal, while it may not be present or as important on... will ask the Governor to express his views or to designate one state agency to represent the official... are designed for safety, non-Federal applicants may be required to demonstrate that the structures...

33 CFR 320.4 - General policies for evaluating permit applications.

Code of Federal Regulations, 2011 CFR

2011-07-01

... specific factor may be given great weight on one proposal, while it may not be present or as important on... will ask the Governor to express his views or to designate one state agency to represent the official... are designed for safety, non-Federal applicants may be required to demonstrate that the structures...

Engaging Young Children in Collective Curriculum Design

ERIC Educational Resources Information Center

Goulart, Maria Ines Mafra; Roth, Wolff-Michael

2010-01-01

In this study we investigate how 5-year-old children in Brazil and their teachers collectively design science curriculum. More specifically, we develop an agency|structure dialectic as a framework to describe this collective praxis in which science curriculum may emerge as the result of children-teacher transactions rather than as a result of…

DESAP 1: A structural design program with stress and displacement constraints. Volume 1: Theoretical and user's manual

NASA Technical Reports Server (NTRS)

Kiusalaas, J.; Reddy, G. B.

1977-01-01

A finite element program is presented for computer-automated, minimum weight design of elastic structures with constraints on stresses (including local instability criteria) and displacements. Volume 1 of the report contains the theoretical and user's manual of the program. Sample problems and the listing of the program are included in Volumes 2 and 3. The element subroutines are organized so as to facilitate additions and changes by the user. As a result, a relatively minor programming effort would be required to make DESAP 1 into a special purpose program to handle the user's specific design requirements and failure criteria.

Application of Pi Preform Composite Joints in Fabrication of NASA Composite Crew Module Demonstration Structure

NASA Technical Reports Server (NTRS)

Higgins, John E.; Pelham, Larry

2008-01-01

This paper will describe unique and extensive use of pre-woven and impregnated pi cross-sections in fabrication of a carbon composite demonstration structure for the Composite Crew Module (CCM) Program. The program is managed by the NASA Safety and Engineering Center with participants from ten NASA Centers and AFRL. Multiple aerospace contractors are participating in the design development, tooling and fabrication effort as well. The goal of the program is to develop an agency wide design team for composite habitable spacecraft. The specific goals for this development project are: a) To gain hands on experience in design, building and testing a composite crew module. b) To validate key assumptions by resolving composite spacecraft design details through fabrication and testing of hardware. This paper will focus on the design and fabrication issues supporting selection of the Lockheed Martin patented Pi pre-form to provide sound composite joints a numerous locations in the structure. This abstract is based on Preliminary Design data. The final design will continue to evolve through the fall of 2007 with fabrication mostly completed by conference date.

Fabricating biomedical origami: a state-of-the-art review

PubMed Central

Johnson, Meredith; Chen, Yue; Hovet, Sierra; Xu, Sheng; Wood, Bradford; Ren, Hongliang; Tokuda, Junichi; Tse, Zion Tsz Ho

2018-01-01

Purpose Origami-based biomedical device design is an emerging technology due to its ability to be deployed from a minimal foldable pattern to a larger volume. This paper aims to review state-of-the-art origami structures applied in the medical device field. Methods Publications and reports of origami structure related to medical device design from the past 10 years are reviewed and categorized according to engineering specifications, including the application field, fabrication material, size/volume, deployment method, manufacturability, and advantages. Results This paper presents an overview of the biomedical applications of devices based on origami structures, including disposable sterilization covers, cardiac catheterization, stent grafts, encapsulation and microsurgery, gastrointestinal microsurgery, laparoscopic surgical grippers, microgrippers, microfluidic devices, and drug delivery. Challenges in terms of materials and fabrication, assembly, modeling and computation design, and clinical adoptability are discussed at the end of this paper to provide guidance for future origami-based design in the medical device field. Conclusion Concepts from origami can be used to design and develop novel medical devices. Origami-based medical device design is currently progressing, with researchers improving design methods, materials, fabrication techniques, and folding efficiency. PMID:28260164

Fabricating biomedical origami: a state-of-the-art review.

PubMed

Johnson, Meredith; Chen, Yue; Hovet, Sierra; Xu, Sheng; Wood, Bradford; Ren, Hongliang; Tokuda, Junichi; Tse, Zion Tsz Ho

2017-11-01

Origami-based biomedical device design is an emerging technology due to its ability to be deployed from a minimal foldable pattern to a larger volume. This paper aims to review state-of-the-art origami structures applied in the medical device field. Publications and reports of origami structure related to medical device design from the past 10 years are reviewed and categorized according to engineering specifications, including the application field, fabrication material, size/volume, deployment method, manufacturability, and advantages. This paper presents an overview of the biomedical applications of devices based on origami structures, including disposable sterilization covers, cardiac catheterization, stent grafts, encapsulation and microsurgery, gastrointestinal microsurgery, laparoscopic surgical grippers, microgrippers, microfluidic devices, and drug delivery. Challenges in terms of materials and fabrication, assembly, modeling and computation design, and clinical adoptability are discussed at the end of this paper to provide guidance for future origami-based design in the medical device field. Concepts from origami can be used to design and develop novel medical devices. Origami-based medical device design is currently progressing, with researchers improving design methods, materials, fabrication techniques, and folding efficiency.

33 CFR 148.8 - How are certifying entities designated and used for purposes of this subchapter?

Code of Federal Regulations, 2011 CFR

2011-07-01

... be associated with its duties for the specific project; (7) In-house availability of, or access to, appropriate technology such as computer modeling programs and hardware or testing materials and equipment; (8...-based structures and project-related structures, systems, and equipment; (6) Technical capabilities...

Semi-Structured Interview Protocol for Constructing Logic Models

ERIC Educational Resources Information Center

Gugiu, P. Cristian; Rodriguez-Campos, Liliana

2007-01-01

This paper details a semi-structured interview protocol that evaluators can use to develop a logic model of a program's services and outcomes. The protocol presents a series of questions, which evaluators can ask of specific program informants, that are designed to: (1) identify key informants basic background and contextual information, (2)…

Adapting the Structural Family Systems Rating to Assess the Patterns of Interaction in Families of Dementia Caregivers

ERIC Educational Resources Information Center

Mitrani, Victoria B.; Feaster, Daniel J.; McCabe, Brian E.; Czaja, Sara J.; Szapocznik, Jose

2005-01-01

Purpose: This study adapted the Structural Family Systems Ratings (SFSR), an observational measure of family interactions, for dementia caregivers. This article presents the development of the SFSR-Dementia Caregiver adaptation (SFSR-DC) and examines relationships between specific family-interaction patterns and caregiver distress. Design and…

33 CFR 148.8 - How are certifying entities designated and used for purposes of this subchapter?

Code of Federal Regulations, 2012 CFR

2012-07-01

... be associated with its duties for the specific project; (7) In-house availability of, or access to, appropriate technology such as computer modeling programs and hardware or testing materials and equipment; (8...-based structures and project-related structures, systems, and equipment; (6) Technical capabilities...

Structure-based Design of Cdk4/6-Specific Inhibitors

DTIC Science & Technology

2005-10-01

were selected to facilitate interactions with residues in neighboring repeats. Moreover,buried hydrophilic residues were mutated to hydrophobic res- Fio ... Russo , A. A., Tong, L., Lee, J.-O., Jeffrey, P. D., and Pavletich, N. P. (1998) tion, although we do not yet have structures for the p18"NK4c Nature 395

Computation-Guided Backbone Grafting of a Discontinuous Motif onto a Protein Scaffold

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

Azoitei, Mihai L.; Correia, Bruno E.; Ban, Yih-En Andrew

2012-02-07

The manipulation of protein backbone structure to control interaction and function is a challenge for protein engineering. We integrated computational design with experimental selection for grafting the backbone and side chains of a two-segment HIV gp120 epitope, targeted by the cross-neutralizing antibody b12, onto an unrelated scaffold protein. The final scaffolds bound b12 with high specificity and with affinity similar to that of gp120, and crystallographic analysis of a scaffold bound to b12 revealed high structural mimicry of the gp120-b12 complex structure. The method can be generalized to design other functional proteins through backbone grafting.

Principles for designing proteins with cavities formed by curved β sheets

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

Marcos, Enrique; Basanta, Benjamin; Chidyausiku, Tamuka M.

Active sites and ligand-binding cavities in native proteins are often formed by curved β sheets, and the ability to control β-sheet curvature would allow design of binding proteins with cavities customized to specific ligands. Toward this end, we investigated the mechanisms controlling β-sheet curvature by studying the geometry of β sheets in naturally occurring protein structures and folding simulations. The principles emerging from this analysis were used to design, de novo, a series of proteins with curved β sheets topped with α helices. Nuclear magnetic resonance and crystal structures of the designs closely match the computational models, showing that β-sheetmore » curvature can be controlled with atomic-level accuracy. Our approach enables the design of proteins with cavities and provides a route to custom design ligand-binding and catalytic sites.« less

Improving Self-Assembly by Varying the Temperature Periodically with Time

NASA Astrophysics Data System (ADS)

Raz, Oren; Jarzynski, Christopher

Self-assembly (SA) is the process by which basic components organize into a larger structure without external guidance. These processes are common in Nature, and also have technological applications, e.g. growing a crystal with a specific structure. So far, artificial SA processes have been designed mostly using diffusive building blocks with high specificity and directionality. The formation of the self-assembled structures is then driven by free-energy minimization into a thermodynamically stable state. In an alternative approach to SA, macroscopic parameters such as temperature, pressure, pH, magnetic field etc., are varied periodically with time. In this case, the SA structures are the stable periodic states of the driven system. Currently there are no design principles for periodically driven SA, other than in the limits of fast or weak driving. We present guiding ideas for self-assembly under periodic driving. As an example, we show a particular case in which self-assembly errors can be dramatically reduced by varying a system's temperature periodically with time. James S. McDonnell Foundation, and the US National Science Foundation: DMR-1506969.

Molecular dynamics simulations to calculate glass transition temperature and elastic constants of novel polyethers.

PubMed

Sarangapani, Radhakrishnan; Reddy, Sreekantha T; Sikder, Arun K

2015-04-01

Molecular dynamics simulations studies are carried out on hydroxyl terminated polyethers that are useful in energetic polymeric binder applications. Energetic polymers derived from oxetanes with heterocyclic side chains with different energetic substituents are designed and simulated under the ensembles of constant particle number, pressure, temperature (NPT) and constant particle number, volume, temperature (NVT). Specific volume of different amorphous polymeric models is predicted using NPT-MD simulations as a function of temperature. Plots of specific volume versus temperature exhibited a characteristic change in slope when amorphous systems change from glassy to rubbery state. Several material properties such as Young's, shear, and bulk modulus, Poisson's ratio, etc. are predicted from equilibrated structures and established the structure-property relations among designed polymers. Energetic performance parameters of these polymers are calculated and results reveal that the performance of the designed polymers is comparable to the benchmark energetic polymers like polyNIMMO, polyAMMO and polyBAMO. Overall, it is worthy remark that this molecular simulations study on novel energetic polyethers provides a good guidance on mastering the design principles and allows us to design novel polymers of tailored properties. Copyright © 2015 Elsevier Inc. All rights reserved.

Low-cost modular array-field designs for flat-panel and concentrator photovoltaic systems

NASA Astrophysics Data System (ADS)

Post, H. N.; Carmichael, D. C.; Alexander, G.; Castle, J. A.

1982-09-01

Described are the design and development of low-cost, modular array fields for flat-panel and concentrator photovoltaic (PV) systems. The objective of the work was to reduce substantially the cost of the array-field Balance-of-System (BOS) subsystems and site-specific design costs as compared to previous PV installations. These subsystems include site preparation, foundations, support structures, electrical writing, grounding, lightning protection, electromagnetic interference considerations, and controls. To reduce these BOS and design costs, standardized modular (building-block) designs for flat-panel and concentrator array fields have been developed that are fully integrated and optimized for lowest life-cycle costs. Using drawings and specifications now available, these building-block designs can be used in multiples to install various size array fields. The developed designs are immediately applicable (1982) and reduce the array-field BOS costs to a fraction of previous costs.

Simulation and Experimental Studies on Grain Selection and Structure Design of the Spiral Selector for Casting Single Crystal Ni-Based Superalloy.

PubMed

Zhang, Hang; Xu, Qingyan

2017-10-27

Grain selection is an important process in single crystal turbine blades manufacturing. Selector structure is a control factor of grain selection, as well as directional solidification (DS). In this study, the grain selection and structure design of the spiral selector were investigated through experimentation and simulation. A heat transfer model and a 3D microstructure growth model were established based on the Cellular automaton-Finite difference (CA-FD) method for the grain selector. Consequently, the temperature field, the microstructure and the grain orientation distribution were simulated and further verified. The average error of the temperature result was less than 1.5%. The grain selection mechanisms were further analyzed and validated through simulations. The structural design specifications of the selector were suggested based on the two grain selection effects. The structural parameters of the spiral selector, namely, the spiral tunnel diameter ( d w ), the spiral pitch ( h b ) and the spiral diameter ( h s ), were studied and the design criteria of these parameters were proposed. The experimental and simulation results demonstrated that the improved selector could accurately and efficiently produce a single crystal structure.

Simulation and Experimental Studies on Grain Selection and Structure Design of the Spiral Selector for Casting Single Crystal Ni-Based Superalloy

PubMed Central

Zhang, Hang; Xu, Qingyan

2017-01-01

Grain selection is an important process in single crystal turbine blades manufacturing. Selector structure is a control factor of grain selection, as well as directional solidification (DS). In this study, the grain selection and structure design of the spiral selector were investigated through experimentation and simulation. A heat transfer model and a 3D microstructure growth model were established based on the Cellular automaton-Finite difference (CA-FD) method for the grain selector. Consequently, the temperature field, the microstructure and the grain orientation distribution were simulated and further verified. The average error of the temperature result was less than 1.5%. The grain selection mechanisms were further analyzed and validated through simulations. The structural design specifications of the selector were suggested based on the two grain selection effects. The structural parameters of the spiral selector, namely, the spiral tunnel diameter (dw), the spiral pitch (hb) and the spiral diameter (hs), were studied and the design criteria of these parameters were proposed. The experimental and simulation results demonstrated that the improved selector could accurately and efficiently produce a single crystal structure. PMID:29077067

23 CFR 650.207 - Plans, specifications and estimates.

Code of Federal Regulations, 2010 CFR

2010-04-01

... OPERATIONS BRIDGES, STRUCTURES, AND HYDRAULICS Erosion and Sediment Control on Highway Construction Projects... highway project designs for the control of erosion and sedimentation and the protection of water quality...

23 CFR 650.207 - Plans, specifications and estimates.

Code of Federal Regulations, 2014 CFR

2014-04-01

... OPERATIONS BRIDGES, STRUCTURES, AND HYDRAULICS Erosion and Sediment Control on Highway Construction Projects... highway project designs for the control of erosion and sedimentation and the protection of water quality...

23 CFR 650.207 - Plans, specifications and estimates.

Code of Federal Regulations, 2013 CFR

2013-04-01

... OPERATIONS BRIDGES, STRUCTURES, AND HYDRAULICS Erosion and Sediment Control on Highway Construction Projects... highway project designs for the control of erosion and sedimentation and the protection of water quality...

23 CFR 650.207 - Plans, specifications and estimates.

Code of Federal Regulations, 2011 CFR

2011-04-01

... OPERATIONS BRIDGES, STRUCTURES, AND HYDRAULICS Erosion and Sediment Control on Highway Construction Projects... highway project designs for the control of erosion and sedimentation and the protection of water quality...

23 CFR 650.207 - Plans, specifications and estimates.

Code of Federal Regulations, 2012 CFR

2012-04-01

... OPERATIONS BRIDGES, STRUCTURES, AND HYDRAULICS Erosion and Sediment Control on Highway Construction Projects... highway project designs for the control of erosion and sedimentation and the protection of water quality...

A probabilistic approach to randomness in geometric configuration of scalable origami structures

NASA Astrophysics Data System (ADS)

Liu, Ke; Paulino, Glaucio; Gardoni, Paolo

2015-03-01

Origami, an ancient paper folding art, has inspired many solutions to modern engineering challenges. The demand for actual engineering applications motivates further investigation in this field. Although rooted from the historic art form, many applications of origami are based on newly designed origami patterns to match the specific requirenments of an engineering problem. The application of origami to structural design problems ranges from micro-structure of materials to large scale deployable shells. For instance, some origami-inspired designs have unique properties such as negative Poisson ratio and flat foldability. However, origami structures are typically constrained by strict mathematical geometric relationships, which in reality, can be easily violated, due to, for example, random imperfections introduced during manufacturing, or non-uniform deformations under working conditions (e.g. due to non-uniform thermal effects). Therefore, the effects of uncertainties in origami-like structures need to be studied in further detail in order to provide a practical guide for scalable origami-inspired engineering designs. Through reliability and probabilistic analysis, we investigate the effect of randomness in origami structures on their mechanical properties. Dislocations of vertices of an origami structure have different impacts on different mechanical properties, and different origami designs could have different sensitivities to imperfections. Thus we aim to provide a preliminary understanding of the structural behavior of some common scalable origami structures subject to randomness in their geometric configurations in order to help transition the technology toward practical applications of origami engineering.

Crystallographic analysis of NHERF1–PLCβ3 interaction provides structural basis for CXCR2 signaling in pancreatic cancer

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

Jiang, Yuanyuan; Wang, Shuo; Holcomb, Joshua

2014-04-04

Highlights: • CXCR2–NHERF1–PLCβ3 complex regulates CXCR2 signaling in pancreatic cancer. • The crystal structure of the NHERF1 PDZ1 domain in complex with PLCβ3. • The structure reveals specificity determinants of PDZ1–PLCβ3 interaction. • Endogenous PLCβ3 in pancreatic cancer cells interacts with both PDZ1 and PDZ2. • Structural basis of the PDZ1–PLCβ3 interaction is valuable in selective drug design. - Abstract: The formation of CXCR2–NHERF1–PLCβ3 macromolecular complex in pancreatic cancer cells regulates CXCR2 signaling activity and plays an important role in tumor proliferation and invasion. We previously have shown that disruption of the NHERF1-mediated CXCR2–PLCβ3 interaction abolishes the CXCR2 signaling cascademore » and inhibits pancreatic tumor growth in vitro and in vivo. Here we report the crystal structure of the NHERF1 PDZ1 domain in complex with the C-terminal PLCβ3 sequence. The structure reveals that the PDZ1–PLCβ3 binding specificity is achieved by numerous hydrogen bonds and hydrophobic contacts with the last four PLCβ3 residues contributing to specific interactions. We also show that PLCβ3 can bind both NHERF1 PDZ1 and PDZ2 in pancreatic cancer cells, consistent with the observation that the peptide binding pockets of these PDZ domains are highly structurally conserved. This study provides an understanding of the structural basis for the PDZ-mediated NHERF1–PLCβ3 interaction that could prove valuable in selective drug design against CXCR2-related cancers.« less

Brayton cycle heat exchanger and duct assembly (HXDA, preliminary design and technology tests

NASA Technical Reports Server (NTRS)

Coombs, M. G.; Morse, C. J.; Graves, R. F.; Gibson, J. C.

1972-01-01

A preliminary design of the heat exchanger and duct assembly (HXDA) for a 60 kwe, closed loop, Brayton cycle space power system is presented. This system is weight optimized within the constraints imposed by the defined structural and operational requirements. Also presented are the results of several small scale tests, directed to obtaining specific design data and/or the resolution of a design approach for long life Brayton cycle heat exchanger systems.

Impact of Aerodynamics and Structures Technology on Heavy Lift Tiltrotors

NASA Technical Reports Server (NTRS)

Acree, C. W., Jr.

2006-01-01

Rotor performance and aeroelastic stability are presented for a 124,000-lb Large Civil Tilt Rotor (LCTR) design. It was designed to carry 120 passengers for 1200 nm, with performance of 350 knots at 30,000 ft altitude. Design features include a low-mounted wing and hingeless rotors, with a very low cruise tip speed of 350 ft/sec. The rotor and wing design processes are described, including rotor optimization methods and wing/rotor aeroelastic stability analyses. New rotor airfoils were designed specifically for the LCTR; the resulting performance improvements are compared to current technology airfoils. Twist, taper and precone optimization are presented, along with the effects of blade flexibility on performance. A new wing airfoil was designed and a composite structure was developed to meet the wing load requirements for certification. Predictions of aeroelastic stability are presented for the optimized rotor and wing, along with summaries of the effects of rotor design parameters on stability.

Development of performance specifications for hybrid modeling of floating wind turbines in wave basin tests

DOE PAGES

Hall, Matthew; Goupee, Andrew; Jonkman, Jason

2017-08-24

Hybrid modeling—combining physical testing and numerical simulation in real time$-$opens new opportunities in floating wind turbine research. Wave basin testing is an important validation step for floating support structure design, but the conventional approaches that use physical wind above the basin are limited by scaling problems in the aerodynamics. Applying wind turbine loads with an actuation system that is controlled by a simulation responding to the basin test in real time offers a way to avoid scaling problems and reduce cost barriers for floating wind turbine design validation in realistic coupled wind and wave conditions. This paper demonstrates the developmentmore » of performance specifications for a system that couples a wave basin experiment with a wind turbine simulation. Two different points for the hybrid coupling are considered: the tower-base interface and the aero-rotor interface (the boundary between aerodynamics and the rotor structure). Analyzing simulations of three floating wind turbine designs across seven load cases reveals the motion and force requirements of the coupling system. By simulating errors in the hybrid coupling system, the sensitivity of the floating wind turbine response to coupling quality can be quantified. The sensitivity results can then be used to determine tolerances for motion tracking errors, force actuation errors, bandwidth limitations, and latency in the hybrid coupling system. These tolerances can guide the design of hybrid coupling systems to achieve desired levels of accuracy. An example demonstrates how the developed methods can be used to generate performance specifications for a system at 1:50 scale. Results show that sensitivities vary significantly between support structure designs and that coupling at the aero-rotor interface has less stringent requirements than those for coupling at the tower base. As a result, the methods and results presented here can inform design of future hybrid coupling systems and enhance understanding of how test results are affected by hybrid coupling quality.« less

Development of performance specifications for hybrid modeling of floating wind turbines in wave basin tests

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

Hall, Matthew; Goupee, Andrew; Jonkman, Jason

Hybrid modeling—combining physical testing and numerical simulation in real time$-$opens new opportunities in floating wind turbine research. Wave basin testing is an important validation step for floating support structure design, but the conventional approaches that use physical wind above the basin are limited by scaling problems in the aerodynamics. Applying wind turbine loads with an actuation system that is controlled by a simulation responding to the basin test in real time offers a way to avoid scaling problems and reduce cost barriers for floating wind turbine design validation in realistic coupled wind and wave conditions. This paper demonstrates the developmentmore » of performance specifications for a system that couples a wave basin experiment with a wind turbine simulation. Two different points for the hybrid coupling are considered: the tower-base interface and the aero-rotor interface (the boundary between aerodynamics and the rotor structure). Analyzing simulations of three floating wind turbine designs across seven load cases reveals the motion and force requirements of the coupling system. By simulating errors in the hybrid coupling system, the sensitivity of the floating wind turbine response to coupling quality can be quantified. The sensitivity results can then be used to determine tolerances for motion tracking errors, force actuation errors, bandwidth limitations, and latency in the hybrid coupling system. These tolerances can guide the design of hybrid coupling systems to achieve desired levels of accuracy. An example demonstrates how the developed methods can be used to generate performance specifications for a system at 1:50 scale. Results show that sensitivities vary significantly between support structure designs and that coupling at the aero-rotor interface has less stringent requirements than those for coupling at the tower base. As a result, the methods and results presented here can inform design of future hybrid coupling systems and enhance understanding of how test results are affected by hybrid coupling quality.« less

Directing folding pathways for multi-component DNA origami nanostructures with complex topology

NASA Astrophysics Data System (ADS)

Marras, A. E.; Zhou, L.; Kolliopoulos, V.; Su, H.-J.; Castro, C. E.

2016-05-01

Molecular self-assembly has become a well-established technique to design complex nanostructures and hierarchical mesoscale assemblies. The typical approach is to design binding complementarity into nucleotide or amino acid sequences to achieve the desired final geometry. However, with an increasing interest in dynamic nanodevices, the need to design structures with motion has necessitated the development of multi-component structures. While this has been achieved through hierarchical assembly of similar structural units, here we focus on the assembly of topologically complex structures, specifically with concentric components, where post-folding assembly is not feasible. We exploit the ability to direct folding pathways to program the sequence of assembly and present a novel approach of designing the strand topology of intermediate folding states to program the topology of the final structure, in this case a DNA origami slider structure that functions much like a piston-cylinder assembly in an engine. The ability to program the sequence and control orientation and topology of multi-component DNA origami nanostructures provides a foundation for a new class of structures with internal and external moving parts and complex scaffold topology. Furthermore, this work provides critical insight to guide the design of intermediate states along a DNA origami folding pathway and to further understand the details of DNA origami self-assembly to more broadly control folding states and landscapes.

Hybrid CMS methods with model reduction for assembly of structures

NASA Technical Reports Server (NTRS)

Farhat, Charbel

1991-01-01

Future on-orbit structures will be designed and built in several stages, each with specific control requirements. Therefore there must be a methodology which can predict the dynamic characteristics of the assembled structure, based on the dynamic characteristics of the subassemblies and their interfaces. The methodology developed by CSC to address this issue is Hybrid Component Mode Synthesis (HCMS). HCMS distinguishes itself from standard component mode synthesis algorithms in the following features: (1) it does not require the subcomponents to have displacement compatible models, which makes it ideal for analyzing the deployment of heterogeneous flexible multibody systems, (2) it incorporates a second-level model reduction scheme at the interface, which makes it much faster than other algorithms and therefore suitable for control purposes, and (3) it does answer specific questions such as 'how does the global fundamental frequency vary if I change the physical parameters of substructure k by a specified amount?'. Because it is based on an energy principle rather than displacement compatibility, this methodology can also help the designer to define an assembly process. Current and future efforts are devoted to applying the HCMS method to design and analyze docking and berthing procedures in orbital construction.

Recent advances in automated protein design and its future challenges.

PubMed

Setiawan, Dani; Brender, Jeffrey; Zhang, Yang

2018-04-25

Protein function is determined by protein structure which is in turn determined by the corresponding protein sequence. If the rules that cause a protein to adopt a particular structure are understood, it should be possible to refine or even redefine the function of a protein by working backwards from the desired structure to the sequence. Automated protein design attempts to calculate the effects of mutations computationally with the goal of more radical or complex transformations than are accessible by experimental techniques. Areas covered: The authors give a brief overview of the recent methodological advances in computer-aided protein design, showing how methodological choices affect final design and how automated protein design can be used to address problems considered beyond traditional protein engineering, including the creation of novel protein scaffolds for drug development. Also, the authors address specifically the future challenges in the development of automated protein design. Expert opinion: Automated protein design holds potential as a protein engineering technique, particularly in cases where screening by combinatorial mutagenesis is problematic. Considering solubility and immunogenicity issues, automated protein design is initially more likely to make an impact as a research tool for exploring basic biology in drug discovery than in the design of protein biologics.

A Method for WD40 Repeat Detection and Secondary Structure Prediction

PubMed Central

Wang, Yang; Jiang, Fan; Zhuo, Zhu; Wu, Xian-Hui; Wu, Yun-Dong

2013-01-01

WD40-repeat proteins (WD40s), as one of the largest protein families in eukaryotes, play vital roles in assembling protein-protein/DNA/RNA complexes. WD40s fold into similar β-propeller structures despite diversified sequences. A program WDSP (WD40 repeat protein Structure Predictor) has been developed to accurately identify WD40 repeats and predict their secondary structures. The method is designed specifically for WD40 proteins by incorporating both local residue information and non-local family-specific structural features. It overcomes the problem of highly diversified protein sequences and variable loops. In addition, WDSP achieves a better prediction in identifying multiple WD40-domain proteins by taking the global combination of repeats into consideration. In secondary structure prediction, the average Q3 accuracy of WDSP in jack-knife test reaches 93.7%. A disease related protein LRRK2 was used as a representive example to demonstrate the structure prediction. PMID:23776530

Blended Design Approach of Long Span Structure and Malay Traditional Architecture

NASA Astrophysics Data System (ADS)

Sundari, Titin

2017-12-01

The growing population in the world is so fast, which is followed by the increasing need of some new and large activities. Architects face the problem on how to facilitate buildings with various activities such as for large meeting, conference, indoors gymnasium and sports, and many others. The long span structure of building is one of the solutions to solve that problem. Generally, large buildings which implemented this structure will look as a technological, modern and futuristic ones or even neo futuristic performance. But on the other hand, many people still want to enjoy the specific and unique senses of local traditional architecture. So is the Malay people who want an easy pleasant large facilities which can be fulfilled by implementing modern long span building structure technology. In the same time, their unique sense of Malay traditional architecture can still be maintained. To overcome this double problems of design, it needs a blended design approach of long span structure and Malay Traditional Architecture.

Search and design of nonmagnetic centrosymmetric layered crystals with large local spin polarization

NASA Astrophysics Data System (ADS)

Liu, Qihang; Zhang, Xiuwen; Jin, Hosub; Lam, Kanber; Im, Jino; Freeman, Arthur J.; Zunger, Alex

2015-06-01

Until recently, spin polarization in nonmagnetic materials was the exclusive territory of noncentrosymmetric structures. It was recently shown that a form of "hidden spin polarization" (named the "Rashba-2" or "R-2" effect) could exist in globally centrosymmetric crystals provided the individual layers belong to polar point group symmetries. This realization could considerably broaden the range of materials that might be considered for spin-polarization spintronic applications to include the hitherto "forbidden spintronic compound" that belongs to centrosymmetric symmetries. Here we take the necessary steps to transition from such general, material-agnostic condensed matter theory arguments to material-specific "design principles" that could aid future laboratory search of R-2 materials. Specifically, we (i) classify different prototype layered structures that have been broadly studied in the literature in terms of their expected R-2 behavior, including the B i2S e3 -structure type (a prototype topological insulator), Mo S2 -structure type (a prototype valleytronic compound), and LaBiO S2 -structure type (a host of superconductivity upon doping); (ii) formulate the properties that ideal R-2 compounds should have in terms of combination of their global unit cell symmetries with specific point group symmetries of their constituent "sectors"; and (iii) use first-principles band theory to search for compounds from the prototype family of LaOBi S2 -type structures that satisfy these R-2 design metrics. We initially consider both stable and hypothetical M'O M X2 (M': Sc, Y, La, Ce, Pr, Nd, Al, Ga, In, Tl; M: P, As, Sb, Bi; X: S, Se, Te) compounds to establish an understanding of trends of R-2 with composition, and then indicate the predictions that are expected to be stable and synthesizable. We predict large spin splittings (up to ˜200 meV for holes in LaOBiT e2 ) as well as surface Rashba states. Experimental testing of such predictions is called for.

Structure-based engineering of a pectate lyase with improved specific activity for ramie degumming.

PubMed

Zhou, Zhanping; Liu, Yang; Chang, Zhenying; Wang, Huilin; Leier, André; Marquez-Lago, Tatiana T; Ma, Yanhe; Li, Jian; Song, Jiangning

2017-04-01

Biotechnological applications of microbial pectate lyases (Pels) in plant fiber processing are promising, eco-friendly substitutes for conventional chemical degumming processes. However, to potentiate the enzymes' use for industrial applications, resolving the molecular structure to elucidate catalytic mechanisms becomes necessary. In this manuscript, we report the high resolution (1.45 Å) crystal structure of pectate lyase (pelN) from Paenibacillus sp. 0602 in apo form. Through sequence alignment and structural superposition with other members of the polysaccharide lyase (PL) family 1 (PL1), we determined that pelN shares the characteristic right-handed β-helix and is structurally similar to other members of the PL1 family, while exhibiting key differences in terms of catalytic and substrate binding residues. Then, based on information from structure alignments with other PLs, we engineered a novel pelN. Our rational design yielded a pelN mutant with a temperature for enzymatic activity optimally shifted from 67.5 to 60 °C. Most importantly, this pelN mutant displayed both higher specific activity and ramie fiber degumming ability when compared with the wild-type enzyme. Altogether, our rational design method shows great potential for industrial applications. Moreover, we expect the reported high-resolution crystal structure to provide a solid foundation for future rational, structure-based engineering of genetically enhanced pelNs.

Wind/Tornado Guidelines Study

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

Ng, D.S.; Holman, G.S.

1991-10-01

This report documents the strategy employed to develop recommended wind/tornado hazard design guidelines for a New Production Reactor (NRP) currently planned for either the Idaho National Engineering Laboratory (INEL) or the Savannah River (SR) site. The Wind/Tornado Working Group (WTWG), comprising six nationally recognized experts in structural engineering, wind engineering, and meteorology, formulated an independent set of guidelines based on site-specific wind/tornado hazard curves and state-of-the-art tornado missile technology. The basic philosophy was to select realistic wind and missile load specifications, and to meet performance goals by applying conservative structural response evaluation and acceptance criteria. Simplified probabilistic risk analyses (PRAs)more » for wind speeds and missile impact were performed to estimate annual damage risk frequencies for both the INEL and SR sites. These PRAs indicate that the guidelines will lead to facilities that meet the US Department of Energy (DOE) design requirements and that the Nuclear Regulatory Commission guidelines adopted by the DOE for design are adequate to meet the NPR safety goals.« less

Organic Carbamates in Drug Design and Medicinal Chemistry

PubMed Central

2016-01-01

The carbamate group is a key structural motif in many approved drugs and prodrugs. There is an increasing use of carbamates in medicinal chemistry and many derivatives are specifically designed to make drug–target interactions through their carbamate moiety. In this Perspective, we present properties and stabilities of carbamates, reagents and chemical methodologies for the synthesis of carbamates, and recent applications of carbamates in drug design and medicinal chemistry. PMID:25565044

Organic carbamates in drug design and medicinal chemistry.

PubMed

Ghosh, Arun K; Brindisi, Margherita

2015-04-09

The carbamate group is a key structural motif in many approved drugs and prodrugs. There is an increasing use of carbamates in medicinal chemistry and many derivatives are specifically designed to make drug-target interactions through their carbamate moiety. In this Perspective, we present properties and stabilities of carbamates, reagents and chemical methodologies for the synthesis of carbamates, and recent applications of carbamates in drug design and medicinal chemistry.

A Case-Based Approach to Creative Design

DTIC Science & Technology

1993-10-05

for solving the sometimes causal (e.g., the operation of ping-pong ball problem. Each time, the designer has different cues shooter 8) and sometimes...In addi- dance (15) is used to quickly communicate the struc- tion to the desired behavior, prominent visual cues may ture of a design alternative...and vague, incomplete havior. specifications. For example, Si’s mental picture of Structural cues describing the proposed solution, or a submarine

Analysis and Design of Complex Network Environments

DTIC Science & Technology

2012-03-01

and J. Lowe, “The myths and facts behind cyber security risks for industrial control systems ,” in the Proceedings of the VDE Kongress, VDE Congress...questions about 1) how to model them, 2) the design of experiments necessary to discover their structure (and thus adapt system inputs to optimize the...theoretical work that clarifies fundamental limitations of complex networks with network engineering and systems biology to implement specific designs and

Superconducting linear actuator

NASA Technical Reports Server (NTRS)

Johnson, Bruce; Hockney, Richard

1993-01-01

Special actuators are needed to control the orientation of large structures in space-based precision pointing systems. Electromagnetic actuators that presently exist are too large in size and their bandwidth is too low. Hydraulic fluid actuation also presents problems for many space-based applications. Hydraulic oil can escape in space and contaminate the environment around the spacecraft. A research study was performed that selected an electrically-powered linear actuator that can be used to control the orientation of a large pointed structure. This research surveyed available products, analyzed the capabilities of conventional linear actuators, and designed a first-cut candidate superconducting linear actuator. The study first examined theoretical capabilities of electrical actuators and determined their problems with respect to the application and then determined if any presently available actuators or any modifications to available actuator designs would meet the required performance. The best actuator was then selected based on available design, modified design, or new design for this application. The last task was to proceed with a conceptual design. No commercially-available linear actuator or modification capable of meeting the specifications was found. A conventional moving-coil dc linear actuator would meet the specification, but the back-iron for this actuator would weigh approximately 12,000 lbs. A superconducting field coil, however, eliminates the need for back iron, resulting in an actuator weight of approximately 1000 lbs.

Analysis and design of lattice materials for large cord and curvature variations in skin panels of morphing wings

NASA Astrophysics Data System (ADS)

Vigliotti, Andrea; Pasini, Damiano

2015-03-01

In the past few decades, several concepts for morphing wings have been proposed with the aim of improving the structural and aerodynamic performance of conventional aircraft wings. One of the most interesting challenges in the design of a morphing wing is represented by the skin, which needs to meet specific deformation requirements. In particular when morphing involves changes of cord or curvature, the skin is required to undergo large recoverable deformation in the actuation direction, while maintaining the desired shape and strength in the others. One promising material concept that can meet these specifications is represented by lattice materials. This paper examines the use of alternative planar lattices in the embodiment of a skin panel for cord and camber morphing of an aircraft wing. We use a structural homogenization scheme capable of capturing large geometric nonlinearity, to examine the structural performance of lattice skin concepts, as well as to tune their mechanical properties in desired directions.

JETSPIN: A specific-purpose open-source software for simulations of nanofiber electrospinning

NASA Astrophysics Data System (ADS)

Lauricella, Marco; Pontrelli, Giuseppe; Coluzza, Ivan; Pisignano, Dario; Succi, Sauro

2015-12-01

We present the open-source computer program JETSPIN, specifically designed to simulate the electrospinning process of nanofibers. Its capabilities are shown with proper reference to the underlying model, as well as a description of the relevant input variables and associated test-case simulations. The various interactions included in the electrospinning model implemented in JETSPIN are discussed in detail. The code is designed to exploit different computational architectures, from single to parallel processor workstations. This paper provides an overview of JETSPIN, focusing primarily on its structure, parallel implementations, functionality, performance, and availability.

Application of probabilistic analysis/design methods in space programs - The approaches, the status, and the needs

NASA Technical Reports Server (NTRS)

Ryan, Robert S.; Townsend, John S.

1993-01-01

The prospective improvement of probabilistic methods for space program analysis/design entails the further development of theories, codes, and tools which match specific areas of application, the drawing of lessons from previous uses of probability and statistics data bases, the enlargement of data bases (especially in the field of structural failures), and the education of engineers and managers on the advantages of these methods. An evaluation is presently made of the current limitations of probabilistic engineering methods. Recommendations are made for specific applications.

Earth Observatory Satellite system definition study. Report no. 3: Design/cost tradeoff studies. Appendix C: EOS program requirements document

NASA Technical Reports Server (NTRS)

1974-01-01

An analysis of the requirements for the Earth Observatory Satellite (EOS) system specifications is presented. The analysis consists of requirements obtained from existing documentation and those derived from functional analysis. The requirements follow the hierarchy of program, mission, system, and subsystem. The code for designating specific requirements is explained. Among the subjects considered are the following: (1) the traffic model, (2) space shuttle related performance, (3) booster related performance, (4) the data collection system, (5) spacecraft structural tests, and (6) the ground support requirements.

Development of the Plate Tectonics and Seismology markup languages with XML

NASA Astrophysics Data System (ADS)

Babaie, H.; Babaei, A.

2003-04-01

The Extensible Markup Language (XML) and its specifications such as the XSD Schema, allow geologists to design discipline-specific vocabularies such as Seismology Markup Language (SeismML) or Plate Tectonics Markup Language (TectML). These languages make it possible to store and interchange structured geological information over the Web. Development of a geological markup language requires mapping geological concepts, such as "Earthquake" or "Plate" into a UML object model, applying a modeling and design environment. We have selected four inter-related geological concepts: earthquake, fault, plate, and orogeny, and developed four XML Schema Definitions (XSD), that define the relationships, cardinalities, hierarchies, and semantics of these concepts. In such a geological concept model, the UML object "Earthquake" is related to one or more "Wave" objects, each arriving to a seismic station at a specific "DateTime", and relating to a specific "Epicenter" object that lies at a unique "Location". The "Earthquake" object occurs along a "Segment" of a "Fault" object, which is related to a specific "Plate" object. The "Fault" has its own associations with such things as "Bend", "Step", and "Segment", and could be of any kind (e.g., "Thrust", "Transform'). The "Plate" is related to many other objects such as "MOR", "Subduction", and "Forearc", and is associated with an "Orogeny" object that relates to "Deformation" and "Strain" and several other objects. These UML objects were mapped into XML Metadata Interchange (XMI) formats, which were then converted into four XSD Schemas. The schemas were used to create and validate the XML instance documents, and to create a relational database hosting the plate tectonics and seismological data in the Microsoft Access format. The SeismML and TectML allow seismologists and structural geologists, among others, to submit and retrieve structured geological data on the Internet. A seismologist, for example, can submit peer-reviewed and reliable data about a specific earthquake to a Java Server Page on our web site hosting the XML application. Other geologists can readily retrieve the submitted data, saved in files or special tables of the designed database, through a search engine designed with J2EE (JSP, servlet, Java Bean) and XML specifications such as XPath, XPointer, and XSLT. When extended to include all the important concepts of seismology and plate tectonics, the two markup languages will make global interchange of geological data a reality.

Computational redesign of a protein-protein interface for high affinity and binding specificity using modular architecture and naturally occurring template fragments.

PubMed

Potapov, V; Reichmann, D; Abramovich, R; Filchtinski, D; Zohar, N; Ben Halevy, D; Edelman, M; Sobolev, V; Schreiber, G

2008-12-05

A new method is presented for the redesign of protein-protein interfaces, resulting in specificity of the designed pair while maintaining high affinity. The design is based on modular interface architecture and was carried out on the interaction between TEM1 beta-lactamase and its inhibitor protein, beta-lactamase inhibitor protein. The interface between these two proteins is composed of several mostly independent modules. We previously showed that it is possible to delete a complete module without affecting the overall structure of the interface. Here, we replace a complete module with structure fragments taken from nonrelated proteins. Nature-optimized fragments were chosen from 10(7) starting templates found in the Protein Data Bank. A procedure was then developed to identify sets of interacting template residues with a backbone arrangement mimicking the original module. This generated a final list of 361 putative replacement modules that were ranked using a novel scoring function based on grouped atom-atom contact surface areas. The top-ranked designed complex exhibited an affinity of at least the wild-type level and a mode of binding that was remarkably specific despite the absence of negative design in the procedure. In retrospect, the combined application of three factors led to the success of the design approach: utilizing the modular construction of the interface, capitalizing on native rather than artificial templates, and ranking with an accurate atom-atom contact surface scoring function.

Design of Critical Components

NASA Technical Reports Server (NTRS)

Hendricks, Robert C.; Zaretsky, Erwin V.

2001-01-01

Critical component design is based on minimizing product failures that results in loss of life. Potential catastrophic failures are reduced to secondary failures where components removed for cause or operating time in the system. Issues of liability and cost of component removal become of paramount importance. Deterministic design with factors of safety and probabilistic design address but lack the essential characteristics for the design of critical components. In deterministic design and fabrication there are heuristic rules and safety factors developed over time for large sets of structural/material components. These factors did not come without cost. Many designs failed and many rules (codes) have standing committees to oversee their proper usage and enforcement. In probabilistic design, not only are failures a given, the failures are calculated; an element of risk is assumed based on empirical failure data for large classes of component operations. Failure of a class of components can be predicted, yet one can not predict when a specific component will fail. The analogy is to the life insurance industry where very careful statistics are book-kept on classes of individuals. For a specific class, life span can be predicted within statistical limits, yet life-span of a specific element of that class can not be predicted.

Long term pavement performance computed parameter : frost penetration

DOT National Transportation Integrated Search

2008-11-01

As the pavement design process moves toward mechanistic-empirical techniques, knowledge of seasonal changes in pavement structural characteristics becomes critical. Specifically, frost penetration information is necessary for determining the effect o...

Investigation of practical applications of H infinity control theory to the design of control systems for large space structures

NASA Technical Reports Server (NTRS)

Irwin, R. Dennis

1988-01-01

The applicability of H infinity control theory to the problems of large space structures (LSS) control was investigated. A complete evaluation to any technique as a candidate for large space structure control involves analytical evaluation, algorithmic evaluation, evaluation via simulation studies, and experimental evaluation. The results of analytical and algorithmic evaluations are documented. The analytical evaluation involves the determination of the appropriateness of the underlying assumptions inherent in the H infinity theory, the determination of the capability of the H infinity theory to achieve the design goals likely to be imposed on an LSS control design, and the identification of any LSS specific simplifications or complications of the theory. The resuls of the analytical evaluation are presented in the form of a tutorial on the subject of H infinity control theory with the LSS control designer in mind. The algorthmic evaluation of H infinity for LSS control pertains to the identification of general, high level algorithms for effecting the application of H infinity to LSS control problems, the identification of specific, numerically reliable algorithms necessary for a computer implementation of the general algorithms, the recommendation of a flexible software system for implementing the H infinity design steps, and ultimately the actual development of the necessary computer codes. Finally, the state of the art in H infinity applications is summarized with a brief outline of the most promising areas of current research.

A new test of computational protein design: predicting posttranslational modification specificity for the enzyme SMYD2.

PubMed

Reynolds, Kimberly A

2015-01-06

In this issue of Structure, Lanouette and colleagues use a combination of computation and experiment to define a specificity motif for the lysine methyltransferase SMYD2. Using this motif, they predict and experimentally verify four new SMYD2 substrates. Copyright © 2015 Elsevier Ltd. All rights reserved.

Firm-Specific Marketing Capital and Job Satisfaction of Marketers: Evidence from Vietnam

ERIC Educational Resources Information Center

Nguyen, Tho D.; Nguyen, Trang T. M.

2011-01-01

Purpose: Based on the resource-based view of the firm, this study aims to examine antecedents and outcomes of firm-specific marketing capital pool invested by marketers in a transition market, Vietnam. Design/methodology/approach: A sample of 528 marketers in Ho Chi Minh City was surveyed to test the theoretical model. Structural equation…

A semi-empirical model relating micro structure to acoustic properties of bimodal porous material

NASA Astrophysics Data System (ADS)

Mosanenzadeh, Shahrzad Ghaffari; Doutres, Olivier; Naguib, Hani E.; Park, Chul B.; Atalla, Noureddine

2015-01-01

Complex morphology of open cell porous media makes it difficult to link microstructural parameters and acoustic behavior of these materials. While morphology determines the overall sound absorption and noise damping effectiveness of a porous structure, little is known on the influence of microstructural configuration on the macroscopic properties. In the present research, a novel bimodal porous structure was designed and developed solely for modeling purposes. For the developed porous structure, it is possible to have direct control on morphological parameters and avoid complications raised by intricate pore geometries. A semi-empirical model is developed to relate microstructural parameters to macroscopic characteristics of porous material using precise characterization results based on the designed bimodal porous structures. This model specifically links macroscopic parameters including static airflow resistivity ( σ ) , thermal characteristic length ( Λ ' ) , viscous characteristic length ( Λ ) , and dynamic tortuosity ( α ∞ ) to microstructural factors such as cell wall thickness ( 2 t ) and reticulation rate ( R w ) . The developed model makes it possible to design the morphology of porous media to achieve optimum sound absorption performance based on the application in hand. This study makes the base for understanding the role of microstructural geometry and morphological factors on the overall macroscopic parameters of porous materials specifically for acoustic capabilities. The next step is to include other microstructural parameters as well to generalize the developed model. In the present paper, pore size was kept constant for eight categories of bimodal foams to study the effect of secondary porous structure on macroscopic properties and overall acoustic behavior of porous media.

Future Technology Workshop: A Collaborative Method for the Design of New Learning Technologies and Activities

ERIC Educational Resources Information Center

Vavoula, Giasemi N.; Sharples, Mike

2007-01-01

We describe the future technology workshop (FTW), a method whereby people with everyday knowledge or experience in a specific area of technology use (such as using digital cameras) envision and design the interactions between current and future technology and activity. Through a series of structured workshop sessions, participants collaborate to…

24 CFR Appendix A to Part 200 - Standards Incorporated by Reference in the Minimum Property Standards for Housing (HUD Handbook...

Code of Federal Regulations, 2012 CFR

2012-04-01

... Design Specification for Wood Construction—1991. American National Standards Institute, 11 West 42nd... Street, New York, NY 10017. ASCE 7-88 Minimum Design Loads for Buildings and Other Structures (Formerly... Institute Building, College Park, MD 20740 Telephone (301) 277-4258. MSI-1-81 Thickness Design—Asphalt...

24 CFR Appendix A to Part 200 - Standards Incorporated by Reference in the Minimum Property Standards for Housing (HUD Handbook...

Code of Federal Regulations, 2011 CFR

2011-04-01

... Design Specification for Wood Construction—1991. American National Standards Institute, 11 West 42nd... Street, New York, NY 10017. ASCE 7-88 Minimum Design Loads for Buildings and Other Structures (Formerly... Institute Building, College Park, MD 20740 Telephone (301) 277-4258. MSI-1-81 Thickness Design—Asphalt...

24 CFR Appendix A to Part 200 - Standards Incorporated by Reference in the Minimum Property Standards for Housing (HUD Handbook...

Code of Federal Regulations, 2013 CFR

2013-04-01

... Design Specification for Wood Construction—1991. American National Standards Institute, 11 West 42nd... Street, New York, NY 10017. ASCE 7-88 Minimum Design Loads for Buildings and Other Structures (Formerly... Institute Building, College Park, MD 20740 Telephone (301) 277-4258. MSI-1-81 Thickness Design—Asphalt...

24 CFR Appendix A to Part 200 - Standards Incorporated by Reference in the Minimum Property Standards for Housing (HUD Handbook...

Code of Federal Regulations, 2014 CFR

2014-04-01

... Design Specification for Wood Construction—1991. American National Standards Institute, 11 West 42nd... Street, New York, NY 10017. ASCE 7-88 Minimum Design Loads for Buildings and Other Structures (Formerly... Institute Building, College Park, MD 20740 Telephone (301) 277-4258. MSI-1-81 Thickness Design—Asphalt...

24 CFR Appendix A to Part 200 - Standards Incorporated by Reference in the Minimum Property Standards for Housing (HUD Handbook...

Code of Federal Regulations, 2010 CFR

2010-04-01

... Design Specification for Wood Construction—1991. American National Standards Institute, 11 West 42nd... Street, New York, NY 10017. ASCE 7-88 Minimum Design Loads for Buildings and Other Structures (Formerly... Institute Building, College Park, MD 20740 Telephone (301) 277-4258. MSI-1-81 Thickness Design—Asphalt...

Fostering Creativity in Design Education: Using the Creative Product Analysis Matrix with Chinese Undergraduates in Macau

ERIC Educational Resources Information Center

Tsai, Kuan Chen

2016-01-01

The purpose of the present study is to explore to what extent the use of a more structured mode of assessing creative products--specifically, the CPAM--could beneficially influence design students' product creativity and creative processes. For this qualitative inquiry, following our CPAM-based intervention, students wrote reflective papers in…

Structure and ligand-based design of P-glycoprotein inhibitors: a historical perspective.

PubMed

Palmeira, Andreia; Sousa, Emilia; Vasconcelos, M Helena; Pinto, Madalena; Fernandes, Miguel X

2012-01-01

Computer-assisted drug design (CADD) is a valuable approach for the discovery of new chemical entities in the field of cancer therapy. There is a pressing need to design and develop new, selective, and safe drugs for the treatment of multidrug resistance (MDR) cancer forms, specifically active against P-glycoprotein (P-gp). Recently, a crystallographic structure for mouse P-gp was obtained. However, for decades the design of new P-gp inhibitors employed mainly ligand-based approaches (SAR, QSAR, 3D-QSAR and pharmacophore studies), and structure-based studies used P-gp homology models. However, some of those results are still the pillars used as a starting point for the design of potential P-gp inhibitors. Here, pharmacophore mapping, (Q)SAR, 3D-QSAR and homology modeling, for the discovery of P-gp inhibitors are reviewed. The importance of these methods for understanding mechanisms of drug resistance at a molecular level, and design P-gp inhibitors drug candidates are discussed. The examples mentioned in the review could provide insights into the wide range of possibilities of using CADD methodologies for the discovery of efficient P-gp inhibitors.

Design of Composite Structures Using Knowledge-Based and Case Based Reasoning

NASA Technical Reports Server (NTRS)

Lambright, Jonathan Paul

1996-01-01

A method of using knowledge based and case based reasoning to assist designers during conceptual design tasks of composite structures was proposed. The cooperative use of heuristics, procedural knowledge, and previous similar design cases suggests a potential reduction in design cycle time and ultimately product lead time. The hypothesis of this work is that the design process of composite structures can be improved by using Case-Based Reasoning (CBR) and Knowledge-Based (KB) reasoning in the early design stages. The technique of using knowledge-based and case-based reasoning facilitates the gathering of disparate information into one location that is easily and readily available. The method suggests that the inclusion of downstream life-cycle issues into the conceptual design phase reduces potential of defective, and sub-optimal composite structures. Three industry experts were interviewed extensively. The experts provided design rules, previous design cases, and test problems. A Knowledge Based Reasoning system was developed using the CLIPS (C Language Interpretive Procedural System) environment and a Case Based Reasoning System was developed using the Design Memory Utility For Sharing Experiences (MUSE) xviii environment. A Design Characteristic State (DCS) was used to document the design specifications, constraints, and problem areas using attribute-value pair relationships. The DCS provided consistent design information between the knowledge base and case base. Results indicated that the use of knowledge based and case based reasoning provided a robust design environment for composite structures. The knowledge base provided design guidance from well defined rules and procedural knowledge. The case base provided suggestions on design and manufacturing techniques based on previous similar designs and warnings of potential problems and pitfalls. The case base complemented the knowledge base and extended the problem solving capability beyond the existence of limited well defined rules. The findings indicated that the technique is most effective when used as a design aid and not as a tool to totally automate the composites design process. Other areas of application and implications for future research are discussed.

A Framework for Preliminary Design of Aircraft Structures Based on Process Information. Part 1

NASA Technical Reports Server (NTRS)

Rais-Rohani, Masoud

1998-01-01

This report discusses the general framework and development of a computational tool for preliminary design of aircraft structures based on process information. The described methodology is suitable for multidisciplinary design optimization (MDO) activities associated with integrated product and process development (IPPD). The framework consists of three parts: (1) product and process definitions; (2) engineering synthesis, and (3) optimization. The product and process definitions are part of input information provided by the design team. The backbone of the system is its ability to analyze a given structural design for performance as well as manufacturability and cost assessment. The system uses a database on material systems and manufacturing processes. Based on the identified set of design variables and an objective function, the system is capable of performing optimization subject to manufacturability, cost, and performance constraints. The accuracy of the manufacturability measures and cost models discussed here depend largely on the available data on specific methods of manufacture and assembly and associated labor requirements. As such, our focus in this research has been on the methodology itself and not so much on its accurate implementation in an industrial setting. A three-tier approach is presented for an IPPD-MDO based design of aircraft structures. The variable-complexity cost estimation methodology and an approach for integrating manufacturing cost assessment into design process are also discussed. This report is presented in two parts. In the first part, the design methodology is presented, and the computational design tool is described. In the second part, a prototype model of the preliminary design Tool for Aircraft Structures based on Process Information (TASPI) is described. Part two also contains an example problem that applies the methodology described here for evaluation of six different design concepts for a wing spar.

Design of a recumbent seating system

NASA Technical Reports Server (NTRS)

Croyle, Scott; Delarosa, Jose; George, Daren; Hinkle, Cathy; Karas, Stephen

1993-01-01

Future space shuttle missions presented by NASA might require the shuttle to rendezvous with the Russian space station Mir for the purpose of transporting astronauts back to earth. Due to the atrophied state of these astronauts, a special seating system must be designed for their transportation. The main functions of this seating system are to support and restrain the astronauts during normal reentry flight and to dampen some of the loading that might occur in a crash situation. Through research, the design team developed many concept variants for these functional requirements. By evaluating each variant, the concepts were eliminated until the four most attractive designs remained. The team used a decision matrix to determine the best concept to carry through embodiment. This concept involved using struts for support during reentry flight and a spring damper/shock absorber system to dampen crash landing loads. The embodiment design process consisted of defining the layout of each of the main functional components, specifically, the seat structure and the strut structure. Through the use of MCS/pal two, the design was refined until it could handle all required loads and dampen to the forces specified. The auxiliary function carriers were then considered. Following the design of these components, the complete final layout could be determined. It is concluded that the final design meets all specifications outlined in the conceptual design. The main advantages of this design are its low weight, simplicity, and large amount of function sharing between different components. The disassembly of this design could potentially present a problem because of time and size constraints involved. Overall, this design meets or exceeds all functional requirements.

Programming Support Library (PSL). Users Manual.

DTIC Science & Technology

1978-05-01

which provides the tools to organize, implement, and control computer program develop- ment. This involves the support of the actual programming process...provides the tools toorganize, implement, and control computer program development. The system is designed specifically to support top-down development...Structured Programming are finding increasing application in the computing community. Structured programs are, however, difficult to write in

Introduction to session on materials and structures

NASA Technical Reports Server (NTRS)

Vosteen, L. F.

1978-01-01

A review was given of the development of composites for aircraft. Supporting base technology and the Aircraft Energy Efficiency Composites Program are included. Specific topics discussed include: (1) environmental effects on materials; (2) material quality and chemical characterization; (3) design and analysis methods; (4) structural durability; (5) impact sensitivity; (6) carbon fiber electrical effects; and (7) composite components.

Getting off the Straight and Narrow: Exploiting Non-Linear, Interactive Narrative Structures in Digital Stories for Language Teaching

ERIC Educational Resources Information Center

Prosser, Andrew

2014-01-01

Digital storytelling is already used extensively in language education. Web documentaries, particularly in terms of design and narrative structure, provide an extension of the digital storytelling concept, specifically in terms of increased interactivity. Using a model of interactive, non-linear storytelling, originally derived from computer game…

What Does Global Migration Network Say about Recent Changes in the World System Structure?

ERIC Educational Resources Information Center

Zinkina, Julia; Korotayev, Andrey

2014-01-01

Purpose: The aim of this paper is to investigate whether the structure of the international migration system has remained stable through the recent turbulent changes in the world system. Design/methodology/approach: The methodology draws on the social network analysis framework--but with some noteworthy limitations stipulated by the specifics of…

Designing Place-Based Interventions for Sustainability and Replicability: The Case of GO! Austin/VAMOS! Austin

PubMed Central

Hussaini, Aliya; Pulido, Carmen Llanes; Basu, Semonti; Ranjit, Nalini

2018-01-01

Place-based health efforts account for the role of the community environment in shaping decisions and circumstances that affect population well-being. Such efforts, rooted as they are in the theory that health is socially determined, mobilize resources for health promotion that are not typically used, and offer a more informed and robust way of promoting health outcomes within a community. Common criticisms of place-based work include the difficulty of replication, since engagement is so specific to a place, and limited sustainability of the work, in the absence of continued institutional structures, both within the community and supporting structures outside the community, to keep these initiatives resilient. This paper describes a place-based initiative, GO! Austin/VAMOS! Austin (GAVA), which was designed to harness the strengths of place-based work—namely, its specificity to place and community. From the start, the project was designed to balance this specificity with a focus on developing and utilizing a standardized set of evidence-informed implementation and evaluation approaches and tools that were flexible enough to be modified for specific settings. This was accompanied by an emphasis on leadership and capacity building within resident leaders, which provided for informed intervention and demand building capacity, but also for longevity as partners, philanthropic, and otherwise, moved in and out of the work. PMID:29623272

Designing Place-Based Interventions for Sustainability and Replicability: The Case of GO! Austin/VAMOS! Austin.

PubMed

Hussaini, Aliya; Pulido, Carmen Llanes; Basu, Semonti; Ranjit, Nalini

2018-01-01

Place-based health efforts account for the role of the community environment in shaping decisions and circumstances that affect population well-being. Such efforts, rooted as they are in the theory that health is socially determined, mobilize resources for health promotion that are not typically used, and offer a more informed and robust way of promoting health outcomes within a community. Common criticisms of place-based work include the difficulty of replication , since engagement is so specific to a place, and limited sustainability of the work, in the absence of continued institutional structures, both within the community and supporting structures outside the community, to keep these initiatives resilient. This paper describes a place-based initiative, GO! Austin/VAMOS! Austin (GAVA), which was designed to harness the strengths of place-based work-namely, its specificity to place and community. From the start, the project was designed to balance this specificity with a focus on developing and utilizing a standardized set of evidence-informed implementation and evaluation approaches and tools that were flexible enough to be modified for specific settings. This was accompanied by an emphasis on leadership and capacity building within resident leaders, which provided for informed intervention and demand building capacity, but also for longevity as partners, philanthropic, and otherwise, moved in and out of the work.

Fault-tolerant control of large space structures using the stable factorization approach

NASA Technical Reports Server (NTRS)

Razavi, H. C.; Mehra, R. K.; Vidyasagar, M.

1986-01-01

Large space structures are characterized by the following features: they are in general infinite-dimensional systems, and have large numbers of undamped or lightly damped poles. Any attempt to apply linear control theory to large space structures must therefore take into account these features. Phase I consisted of an attempt to apply the recently developed Stable Factorization (SF) design philosophy to problems of large space structures, with particular attention to the aspects of robustness and fault tolerance. The final report on the Phase I effort consists of four sections, each devoted to one task. The first three sections report theoretical results, while the last consists of a design example. Significant results were obtained in all four tasks of the project. More specifically, an innovative approach to order reduction was obtained, stabilizing controller structures for plants with an infinite number of unstable poles were determined under some conditions, conditions for simultaneous stabilizability of an infinite number of plants were explored, and a fault tolerance controller design that stabilizes a flexible structure model was obtained which is robust against one failure condition.

Flat-plate photovoltaic array design optimization

NASA Technical Reports Server (NTRS)

Ross, R. G., Jr.

1980-01-01

An analysis is presented which integrates the results of specific studies in the areas of photovoltaic structural design optimization, optimization of array series/parallel circuit design, thermal design optimization, and optimization of environmental protection features. The analysis is based on minimizing the total photovoltaic system life-cycle energy cost including repair and replacement of failed cells and modules. This approach is shown to be a useful technique for array optimization, particularly when time-dependent parameters such as array degradation and maintenance are involved.

Relation between the Fluctuating Wall Pressure and the Turbulent Structure of a Boundary Layer on a Cylinder in Axial Flow

DTIC Science & Technology

1993-08-12

Shop for their expert assistance during thze design ard development ur the wind tunnel and experimental apparatus; Drs. Alan L. Kistler, Seth Lichter...vertical wind tunnel was designed and built for this research. I With the test section in a vertical orientation, gravity effects leading to cylinder sag...were eliminated. The overall design and layout of the wind tunnel, as well as specific design features incorporated into the wind tunnel to satisfy

Structural Impact of Construction Loads : [Technical Summary

DOT National Transportation Integrated Search

2012-01-01

Numerous bridge construction accidents have occurred : because of construction loadings, which are an underemphasized : topic in many specifications and design : manuals. Bridge girders are least stable during the : construction phase, so it is impor...

Structural Impact of Construction Loads

DOT National Transportation Integrated Search

2012-08-01

Numerous bridge construction accidents have occurred across the country because of construction loadings, which are an underemphasized : topic in many DOT specifications and design manuals. Bridge girders are least stable when they are subjected to c...

Structural Impact of Construction Loads

DOT National Transportation Integrated Search

2012-08-01

Numerous bridge construction accidents have occurred across the country because of construction loadings, which are an underemphasized topic in many DOT specifications and design manuals. Bridge girders are least stable when they are subjected to con...

Salt bridges: geometrically specific, designable interactions.

PubMed

Donald, Jason E; Kulp, Daniel W; DeGrado, William F

2011-03-01

Salt bridges occur frequently in proteins, providing conformational specificity and contributing to molecular recognition and catalysis. We present a comprehensive analysis of these interactions in protein structures by surveying a large database of protein structures. Salt bridges between Asp or Glu and His, Arg, or Lys display extremely well-defined geometric preferences. Several previously observed preferences are confirmed, and others that were previously unrecognized are discovered. Salt bridges are explored for their preferences for different separations in sequence and in space, geometric preferences within proteins and at protein-protein interfaces, co-operativity in networked salt bridges, inclusion within metal-binding sites, preference for acidic electrons, apparent conformational side chain entropy reduction on formation, and degree of burial. Salt bridges occur far more frequently between residues at close than distant sequence separations, but, at close distances, there remain strong preferences for salt bridges at specific separations. Specific types of complex salt bridges, involving three or more members, are also discovered. As we observe a strong relationship between the propensity to form a salt bridge and the placement of salt-bridging residues in protein sequences, we discuss the role that salt bridges might play in kinetically influencing protein folding and thermodynamically stabilizing the native conformation. We also develop a quantitative method to select appropriate crystal structure resolution and B-factor cutoffs. Detailed knowledge of these geometric and sequence dependences should aid de novo design and prediction algorithms. Copyright © 2010 Wiley-Liss, Inc.

Accurate de novo design of hyperstable constrained peptides

PubMed Central

Bhardwaj, Gaurav; Mulligan, Vikram Khipple; Bahl, Christopher D.; Gilmore, Jason M.; Harvey, Peta J.; Cheneval, Olivier; Buchko, Garry W.; Pulavarti, Surya V.S.R.K.; Kaas, Quentin; Eletsky, Alexander; Huang, Po-Ssu; Johnsen, William A.; Greisen, Per; Rocklin, Gabriel J.; Song, Yifan; Linsky, Thomas W.; Watkins, Andrew; Rettie, Stephen A.; Xu, Xianzhong; Carter, Lauren P.; Bonneau, Richard; Olson, James M.; Coutsias, Evangelos; Correnti, Colin E.; Szyperski, Thomas; Craik, David J.; Baker, David

2016-01-01

Summary Naturally occurring, pharmacologically active peptides constrained with covalent crosslinks generally have shapes evolved to fit precisely into binding pockets on their targets. Such peptides can have excellent pharmaceutical properties, combining the stability and tissue penetration of small molecule drugs with the specificity of much larger protein therapeutics. The ability to design constrained peptides with precisely specified tertiary structures would enable the design of shape-complementary inhibitors of arbitrary targets. Here we describe the development of computational methods for de novo design of conformationally-restricted peptides, and the use of these methods to design 15–50 residue disulfide-crosslinked and heterochiral N-C backbone-cyclized peptides. These peptides are exceptionally stable to thermal and chemical denaturation, and twelve experimentally-determined X-ray and NMR structures are nearly identical to the computational models. The computational design methods and stable scaffolds presented here provide the basis for development of a new generation of peptide-based drugs. PMID:27626386

Polymorphic design of DNA origami structures through mechanical control of modular components.

PubMed

Lee, Chanseok; Lee, Jae Young; Kim, Do-Nyun

2017-12-12

Scaffolded DNA origami enables the bottom-up fabrication of diverse DNA nanostructures by designing hundreds of staple strands, comprised of complementary sequences to the specific binding locations of a scaffold strand. Despite its exceptionally high design flexibility, poor reusability of staples has been one of the major hurdles to fabricate assorted DNA constructs in an effective way. Here we provide a rational module-based design approach to create distinct bent shapes with controllable geometries and flexibilities from a single, reference set of staples. By revising the staple connectivity within the desired module, we can control the location, stiffness, and included angle of hinges precisely, enabling the construction of dozens of single- or multiple-hinge structures with the replacement of staple strands up to 12.8% only. Our design approach, combined with computational shape prediction and analysis, can provide a versatile and cost-effective procedure in the design of DNA origami shapes with stiffness-tunable units.

A new class of HIV-1 protease inhibitor: the crystallographic structure, inhibition and chemical synthesis of an aminimide peptide isostere.

PubMed

Rutenber, E E; McPhee, F; Kaplan, A P; Gallion, S L; Hogan, J C; Craik, C S; Stroud, R M

1996-09-01

The essential role of HIV-1 protease (HIV-1 PR) in the viral life cycle makes it an attractive target for the development of substrate-based inhibitors that may find efficacy as anti-AIDS drugs. However, resistance has arisen to potent peptidomimetic drugs necessitating the further development of novel chemical backbones for diversity based chemistry focused on probing the active site for inhibitor interactions and binding modes that evade protease resistance. AQ148 is a potent inhibitor of HIV-1 PR and represents a new class of transition state analogues incorporating an aminimide peptide isostere. A 3-D crystallographic structure of AQ148, a tetrapeptide isostere, has been determined in complex with its target HIV-1 PR to a resolution of 2.5 A and used to evaluate the specific structural determinants of AQ148 potency and to correlate structure-activity relationships within the class of related compounds. AQ148 is a competitive inhibitor of HIV-1 PR with a Ki value of 137 nM. Twenty-nine derivatives have been synthesized and chemical modifications have been made at the P1, P2, P1', and P2' sites. The atomic resolution structure of AQ148 bound to HIV-1 PR reveals both an inhibitor binding mode that closely resembles that of other peptidomimetic inhibitors and specific protein/inhibitor interactions that correlate with structure-activity relationships. The structure provides the basis for the design, synthesis and evaluation of the next generation of hydroxyethyl aminimide inhibitors. The aminimide peptide isostere is a scaffold with favorable biological properties well suited to both the combinatorial methods of peptidomimesis and the rational design of potent and specific substrate-based analogues.

Multiobjective optimization techniques for structural design

NASA Technical Reports Server (NTRS)

Rao, S. S.

1984-01-01

The multiobjective programming techniques are important in the design of complex structural systems whose quality depends generally on a number of different and often conflicting objective functions which cannot be combined into a single design objective. The applicability of multiobjective optimization techniques is studied with reference to simple design problems. Specifically, the parameter optimization of a cantilever beam with a tip mass and a three-degree-of-freedom vabration isolation system and the trajectory optimization of a cantilever beam are considered. The solutions of these multicriteria design problems are attempted by using global criterion, utility function, game theory, goal programming, goal attainment, bounded objective function, and lexicographic methods. It has been observed that the game theory approach required the maximum computational effort, but it yielded better optimum solutions with proper balance of the various objective functions in all the cases.

Application of Laminar Flow Control Technology to Long-Range Transport Design

NASA Technical Reports Server (NTRS)

Gratzer, L. B.; George-Falvy, D.

1978-01-01

The impact of laminar flow control (LFC) technology on aircraft structural design concepts and systems was discussed and the corresponding benefits were shown in terms of performance and fuel economy. Specific topics discussed include: (1) recent advances in laminar boundary layer development and stability analysis techniques in terms of suction requirements and wing suction surface design; (2) validation of theory and realistic simulation of disturbances and off-design conditions by wind tunnel testing; (3) compatibility of aerodynamic design of airfoils and wings with LFC requirements; (4) structural alternatives involving advanced alloys or composites in combinations made possible by advanced materials processing and manufacturing techniques; (5) addition of suction compressor and drive units and their location on the aircraft; and (6) problems associated with operation of LFC aircraft, including accumulation of insects at low altitudes and environmental considerations.

Study on Design of High Efficiency and Light Weight Composite Propeller Blade for a Regional Turboprop Aircraft

NASA Astrophysics Data System (ADS)

Kong, Changduk; Lee, Kyungsun

2013-03-01

In this study, aerodynamic and structural design of the composite propeller blade for a regional turboprop aircraft is performed. The thin and wide chord propeller blade of high speed turboprop aircraft should have proper strength and stiffness to carry various kinds of loads such as high aerodynamic bending and twisting moments and centrifugal forces. Therefore the skin-spar-foam sandwich structure using high strength and stiffness carbon/epoxy composite materials is used to improve the lightness. A specific design procedure is proposed in this work as follows; firstly the aerodynamic configuration design, which is acceptable for the design requirements, is carried out using the in-house code developed by authors, secondly the structure design loads are determined through the aerodynamic load case analysis, thirdly the spar flange and the skin are preliminarily sized by consideration of major bending moments and shear forces using both the netting rule and the rule of mixture, and finally, the stress analysis is performed to confirm the structural safety and stability using finite element analysis commercial code, MSC. NASTRAN/PATRAN. Furthermore the additional analysis is performed to confirm the structural safety due to bird strike impact on the blade during flight operation using a commercial code, ANSYS. To realize the proposed propeller design, the prototype blades are manufactured by the following procedure; the carbon/epoxy composite fabric prepregs are laid up for skin and spar on a mold using the hand lay-up method and consolidated with a proper temperature and vacuum in the oven. To finalize the structural design, the full-scale static structural test is performed under the simulated aerodynamic loads using 3 point loading method. From the experimental results, it is found that the designed blade has a good structural integrity, and the measured results agree well with the analytical results as well.

Design of SERS nanoprobes for Raman imaging: materials, critical factors and architectures.

PubMed

Li, Mingwang; Qiu, Yuanyuan; Fan, Chenchen; Cui, Kai; Zhang, Yongming; Xiao, Zeyu

2018-05-01

Raman imaging yields high specificity and sensitivity when compared to other imaging modalities, mainly due to its fingerprint signature. However, intrinsic Raman signals are weak, thus limiting medical applications of Raman imaging. By adsorbing Raman molecules onto specific nanostructures such as noble metals, Raman signals can be significantly enhanced, termed surface-enhanced Raman scattering (SERS). Recent years have witnessed great interest in the development of SERS nanoprobes for Raman imaging. Rationally designed SERS nanoprobes have greatly enhanced Raman signals by several orders of magnitude, thus showing great potential for biomedical applications. In this review we elaborate on recent progress in design strategies with emphasis on material properties, modifying factors, and structural parameters.

Development of flame-resistant structures for use in the Apollo and Skylab programs

NASA Technical Reports Server (NTRS)

Coskren, R. J.

1973-01-01

Flame-resistant materials have been designed and fabricated to meet certain end-use criteria established by NASA with emphasis on meeting established flammability standards. The program had three general phases: (1) fabrication of candidate sample structures for evaluation by the Structures and Mechanics Division and/or NASA contractors; (2) physical testing of the structures developed; and (3) supply of required quantities of specific items for fabrication into prototype and/or flight items for the Apollo and Skylab programs.

Design solutions for dome and main structure (mount) of giant telescopes

NASA Astrophysics Data System (ADS)

Murga, Gaizka; Bilbao, Armando; de Bilbao, Lander; Lorentz, Thomas E.

2016-07-01

During the last recent years, designs for several giant telescopes ranging from 20 to 40m in diameter are being developed: European Extremely Large Telescope Telescope (TMT). (E-ELT), Giant Magellan Telescope (GMT) and Thirty Meter It is evident that simple direct up-scaling of solutions that were more or less successful in the 8 to 10m class telescopes can not lead to viable designs for the future giant telescopes. New solutions are required to provide adequate load sharing, to cope with the large-scale derived deflections and to provide the required compliance, or to respond to structure-mechanism control interaction issues, among others. From IDOM experience in the development of the Dome and Main Structure of the European Extremely Large Telescope and our participation in some other giant telescopes, this paper reviews several design approaches for the main mechanisms and key structural parts of enclosures and mounts/main structures for giant telescopes, analyzing pros and cons of the different alternatives and outlining the preferred design schemes. The assessment is carried out mainly from a technical and performance-based angle but it also considers specific logistical issues for the assembly of these large telescopes in remote and space-limited areas, together with cost and schedule related issues.

The Structural Ceramics Database: Technical Foundations

PubMed Central

Munro, R. G.; Hwang, F. Y.; Hubbard, C. R.

1989-01-01

The development of a computerized database on advanced structural ceramics can play a critical role in fostering the widespread use of ceramics in industry and in advanced technologies. A computerized database may be the most effective means of accelerating technology development by enabling new materials to be incorporated into designs far more rapidly than would have been possible with traditional information transfer processes. Faster, more efficient access to critical data is the basis for creating this technological advantage. Further, a computerized database provides the means for a more consistent treatment of data, greater quality control and product reliability, and improved continuity of research and development programs. A preliminary system has been completed as phase one of an ongoing program to establish the Structural Ceramics Database system. The system is designed to be used on personal computers. Developed in a modular design, the preliminary system is focused on the thermal properties of monolithic ceramics. The initial modules consist of materials specification, thermal expansion, thermal conductivity, thermal diffusivity, specific heat, thermal shock resistance, and a bibliography of data references. Query and output programs also have been developed for use with these modules. The latter program elements, along with the database modules, will be subjected to several stages of testing and refinement in the second phase of this effort. The goal of the refinement process will be the establishment of this system as a user-friendly prototype. Three primary considerations provide the guidelines to the system’s development: (1) The user’s needs; (2) The nature of materials properties; and (3) The requirements of the programming language. The present report discusses the manner and rationale by which each of these considerations leads to specific features in the design of the system. PMID:28053397

Application of Locked Nucleic Acid (LNA) Primer and PCR Clamping by LNA Oligonucleotide to Enhance the Amplification of Internal Transcribed Spacer (ITS) Regions in Investigating the Community Structures of Plant-Associated Fungi.

PubMed

Ikenaga, Makoto; Tabuchi, Masakazu; Kawauchi, Tomohiro; Sakai, Masao

2016-09-29

The simultaneous extraction of host plant DNA severely limits investigations of the community structures of plant-associated fungi due to the similar homologies of sequences in primer-annealing positions between fungi and host plants. Although fungal-specific primers have been designed, plant DNA continues to be excessively amplified by PCR, resulting in the underestimation of community structures. In order to overcome this limitation, locked nucleic acid (LNA) primers and PCR clamping by LNA oligonucleotides have been applied to enhance the amplification of fungal internal transcribed spacer (ITS) regions. LNA primers were designed by converting DNA into LNA, which is specific to fungi, at the forward primer side. LNA oligonucleotides, the sequences of which are complementary to the host plants, were designed by overlapping a few bases with the annealing position of the reverse primer. Plant-specific DNA was then converted into LNA at the shifted position from the 3' end of the primer-binding position. PCR using the LNA technique enhanced the amplification of fungal ITS regions, whereas those of the host plants were more likely to be amplified without the LNA technique. A denaturing gradient gel electrophoresis (DGGE) analysis displayed patterns that reached an acceptable level for investigating the community structures of plant-associated fungi using the LNA technique. The sequences of the bands detected using the LNA technique were mostly affiliated with known isolates. However, some sequences showed low similarities, indicating the potential to identify novel fungi. Thus, the application of the LNA technique is considered effective for widening the scope of community analyses of plant-associated fungi.

Application of Locked Nucleic Acid (LNA) Primer and PCR Clamping by LNA Oligonucleotide to Enhance the Amplification of Internal Transcribed Spacer (ITS) Regions in Investigating the Community Structures of Plant–Associated Fungi

PubMed Central

Ikenaga, Makoto; Tabuchi, Masakazu; Kawauchi, Tomohiro; Sakai, Masao

2016-01-01

The simultaneous extraction of host plant DNA severely limits investigations of the community structures of plant–associated fungi due to the similar homologies of sequences in primer–annealing positions between fungi and host plants. Although fungal-specific primers have been designed, plant DNA continues to be excessively amplified by PCR, resulting in the underestimation of community structures. In order to overcome this limitation, locked nucleic acid (LNA) primers and PCR clamping by LNA oligonucleotides have been applied to enhance the amplification of fungal internal transcribed spacer (ITS) regions. LNA primers were designed by converting DNA into LNA, which is specific to fungi, at the forward primer side. LNA oligonucleotides, the sequences of which are complementary to the host plants, were designed by overlapping a few bases with the annealing position of the reverse primer. Plant-specific DNA was then converted into LNA at the shifted position from the 3′ end of the primer–binding position. PCR using the LNA technique enhanced the amplification of fungal ITS regions, whereas those of the host plants were more likely to be amplified without the LNA technique. A denaturing gradient gel electrophoresis (DGGE) analysis displayed patterns that reached an acceptable level for investigating the community structures of plant–associated fungi using the LNA technique. The sequences of the bands detected using the LNA technique were mostly affiliated with known isolates. However, some sequences showed low similarities, indicating the potential to identify novel fungi. Thus, the application of the LNA technique is considered effective for widening the scope of community analyses of plant–associated fungi. PMID:27600711

ESA's tools for internal charging

NASA Astrophysics Data System (ADS)

Sorensen, J.; Rodgers, D. J.; Ryden, K. A.; Latham, P. M.; Wrenn, G. L.; Levy, L.; Panabiere, G.

2000-06-01

Electrostatic discharges, caused by bulk charging of spacecraft insulating materials, are a major cause of satellite anomalies. A quantitative knowledge of the charge build-up is essential in order to eliminate these problems in the design stage. This is a presentation of ESA's tools to assess whether a given structure is liable to experience electrostatic discharges or not. A study has been made of the physical phenomenon, and an engineering specification has been created to be used to assess a structure for potential discharge problems. The specification has been implemented in a new software DICTAT. The implementation of tests in dedicated facilities is an important part of the specification, and tests have been performed to validate the new tool.

SDDL- SOFTWARE DESIGN AND DOCUMENTATION LANGUAGE

NASA Technical Reports Server (NTRS)

Kleine, H.

1994-01-01

Effective, efficient communication is an essential element of the software development process. The Software Design and Documentation Language (SDDL) provides an effective communication medium to support the design and documentation of complex software applications. SDDL supports communication between all the members of a software design team and provides for the production of informative documentation on the design effort. Even when an entire development task is performed by a single individual, it is important to explicitly express and document communication between the various aspects of the design effort including concept development, program specification, program development, and program maintenance. SDDL ensures that accurate documentation will be available throughout the entire software life cycle. SDDL offers an extremely valuable capability for the design and documentation of complex programming efforts ranging from scientific and engineering applications to data management and business sytems. Throughout the development of a software design, the SDDL generated Software Design Document always represents the definitive word on the current status of the ongoing, dynamic design development process. The document is easily updated and readily accessible in a familiar, informative form to all members of the development team. This makes the Software Design Document an effective instrument for reconciling misunderstandings and disagreements in the development of design specifications, engineering support concepts, and the software design itself. Using the SDDL generated document to analyze the design makes it possible to eliminate many errors that might not be detected until coding and testing is attempted. As a project management aid, the Software Design Document is useful for monitoring progress and for recording task responsibilities. SDDL is a combination of language, processor, and methodology. The SDDL syntax consists of keywords to invoke design structures and a collection of directives which control processor actions. The designer has complete control over the choice of keywords, commanding the capabilities of the processor in a way which is best suited to communicating the intent of the design. The SDDL processor translates the designer's creative thinking into an effective document for communication. The processor performs as many automatic functions as possible, thereby freeing the designer's energy for the creative effort. Document formatting includes graphical highlighting of structure logic, accentuation of structure escapes and module invocations, logic error detection, and special handling of title pages and text segments. The SDDL generated document contains software design summary information including module invocation hierarchy, module cross reference, and cross reference tables of user selected words or phrases appearing in the document. The basic forms of the methodology are module and block structures and the module invocation statement. A design is stated in terms of modules that represent problem abstractions which are complete and independent enough to be treated as separate problem entities. Blocks are lower-level structures used to build the modules. Both kinds of structures may have an initiator part, a terminator part, an escape segment, or a substructure. The SDDL processor is written in PASCAL for batch execution on a DEC VAX series computer under VMS. SDDL was developed in 1981 and last updated in 1984.

The first mammalian aldehyde oxidase crystal structure: insights into substrate specificity.

PubMed

Coelho, Catarina; Mahro, Martin; Trincão, José; Carvalho, Alexandra T P; Ramos, Maria João; Terao, Mineko; Garattini, Enrico; Leimkühler, Silke; Romão, Maria João

2012-11-23

Aldehyde oxidases have pharmacological relevance, and AOX3 is the major drug-metabolizing enzyme in rodents. The crystal structure of mouse AOX3 with kinetics and molecular docking studies provides insights into its enzymatic characteristics. Differences in substrate and inhibitor specificities can be rationalized by comparing the AOX3 and xanthine oxidase structures. The first aldehyde oxidase structure represents a major advance for drug design and mechanistic studies. Aldehyde oxidases (AOXs) are homodimeric proteins belonging to the xanthine oxidase family of molybdenum-containing enzymes. Each 150-kDa monomer contains a FAD redox cofactor, two spectroscopically distinct [2Fe-2S] clusters, and a molybdenum cofactor located within the protein active site. AOXs are characterized by broad range substrate specificity, oxidizing different aldehydes and aromatic N-heterocycles. Despite increasing recognition of its role in the metabolism of drugs and xenobiotics, the physiological function of the protein is still largely unknown. We have crystallized and solved the crystal structure of mouse liver aldehyde oxidase 3 to 2.9 Å. This is the first mammalian AOX whose structure has been solved. The structure provides important insights into the protein active center and further evidence on the catalytic differences characterizing AOX and xanthine oxidoreductase. The mouse liver aldehyde oxidase 3 three-dimensional structure combined with kinetic, mutagenesis data, molecular docking, and molecular dynamics studies make a decisive contribution to understand the molecular basis of its rather broad substrate specificity.

A simplified design of the staggered herringbone micromixer for practical applications

PubMed Central

Du, Yan; Zhang, Zhiyi; Yim, ChaeHo; Lin, Min; Cao, Xudong

2010-01-01

We demonstrated a simple method for the device design of a staggered herringbone micromixer (SHM) using numerical simulation. By correlating the simulated concentrations with channel length, we obtained a series of concentration versus channel length profiles, and used mixing completion length Lm as the only parameter to evaluate the performance of device structure on mixing. Fluorescence quenching experiments were subsequently conducted to verify the optimized SHM structure for a specific application. Good agreement was found between the optimization and the experimental data. Since Lm is straightforward, easily defined and calculated parameter for characterization of mixing performance, this method for designing micromixers is simple and effective for practical applications. PMID:20697584

A simplified design of the staggered herringbone micromixer for practical applications.

PubMed

Du, Yan; Zhang, Zhiyi; Yim, Chaeho; Lin, Min; Cao, Xudong

2010-05-07

We demonstrated a simple method for the device design of a staggered herringbone micromixer (SHM) using numerical simulation. By correlating the simulated concentrations with channel length, we obtained a series of concentration versus channel length profiles, and used mixing completion length L(m) as the only parameter to evaluate the performance of device structure on mixing. Fluorescence quenching experiments were subsequently conducted to verify the optimized SHM structure for a specific application. Good agreement was found between the optimization and the experimental data. Since L(m) is straightforward, easily defined and calculated parameter for characterization of mixing performance, this method for designing micromixers is simple and effective for practical applications.

Design feasibility via ascent optimality for next-generation spacecraft

NASA Astrophysics Data System (ADS)

Miele, A.; Mancuso, S.

This paper deals with the optimization of the ascent trajectories for single-stage-sub-orbit (SSSO), single-stage-to-orbit (SSTO), and two-stage-to-orbit (TSTO) rocket-powered spacecraft. The maximum payload weight problem is studied for different values of the engine specific impulse and spacecraft structural factor. The main conclusions are that: feasibility of SSSO spacecraft is guaranteed for all the parameter combinations considered; feasibility of SSTO spacecraft depends strongly on the parameter combination chosen; not only feasibility of TSTO spacecraft is guaranteed for all the parameter combinations considered, but the TSTO payload is several times the SSTO payload. Improvements in engine specific impulse and spacecraft structural factor are desirable and crucial for SSTO feasibility; indeed, aerodynamic improvements do not yield significant improvements in payload. For SSSO, SSTO, and TSTO spacecraft, simple engineering approximations are developed connecting the maximum payload weight to the engine specific impulse and spacecraft structural factor. With reference to the specific impulse/structural factor domain, these engineering approximations lead to the construction of zero-payload lines separating the feasibility region (positive payload) from the unfeasibility region (negative payload).

Structure of the carboxypeptidase B complex with N-sulfamoyl-L-phenylalanine - a transition state analog of non-specific substrate.

PubMed

Akparov, Valery; Timofeev, Vladimir; Khaliullin, Ilyas; Švedas, Vytas; Kuranova, Inna

2018-03-01

Carboxypeptidase B (EC 3.4.17.2) (CPB) is commonly used in the industrial insulin production and as a template for drug design. However, its ability to discriminate substrates with hydrophobic, hydrophilic, and charged side chains is not well understood. We report structure of CPB complex with a transition state analog N-sulfamoyl-L-phenylalanine solved at 1.74Å. The study provided an insight into structural basis of CPB substrate specificity. Ligand binding is affected by structure-depended conformational changes of Asp255 in S1'-subsite, interactions with Asn144 and Arg145 in C-terminal binding subsite, and Glu270 in the catalytic center. Side chain of the non-specific substrate analog SPhe in comparison with that of specific substrate analog SArg (reported earlier) not only loses favorable electrostatic interactions and two hydrogen bonds with Asp255 and three fixed water molecules, but is forced to be in the unfavorable hydrophilic environment. Thus, Ser207, Gly253, Tyr248, and Asp255 residues play major role in the substrate recognition by S1'-subsite.

Liquid rocket engine centrifugal flow turbopumps. [design criteria

NASA Technical Reports Server (NTRS)

1973-01-01

Design criteria and recommended practices are discussed for the following configurations selected from the design sequence of a liquid rocket engine centrifugal flow turbopump: (1) pump performance including speed, efficiency, and flow range; (2) impeller; (3) housing; and (4) thrust balance system. Hydrodynamic, structural, and mechanical problems are addressed for the achievement of required pump performance within the constraints imposed by the engine/turbopump system. Materials and fabrication specifications are also discussed.

Evolution and coevolution of developmental programs

NASA Astrophysics Data System (ADS)

Jacob, Christian

1999-09-01

The developmental processes of single organisms, such as growth and structure formation, can be described by parallel rewrite systems in the form of Lindenmayer systems, which also allow one to generate geometrical structures in 3D space using turtle interpretation. We present examples of L-systems for growth programs of plant-like structures. Evolution-based programming techniques are applied to design L-systems by Genetic L-system Programming (GLP), demonstrating how developmental programs for plants, exhibiting specific morphogenetic properties can be interactively bred or automatically evolved. Finally, we demonstrate coevolutionary effects among plant populations consisting of different species, interacting with each other, competing for resources like sunlight and nutrients, and evolving successful reproduction strategies in their specific environments.

Kinetoplast DNA minicircles of phloem-restricted Phytomonas associated with wilt diseases of coconut and oil palms have a two-domain structure.

PubMed

Dollet, M; Sturm, N R; Ahomadegbe, J C; Campbell, D A

2001-11-27

We report the cloning and sequencing of the first minicircle from a phloem-restricted, pathogenic Phytomonas sp. (Hart 1) isolated from a coconut palm with hartrot disease. The minicircle possessed a two-domain structure of two conserved regions, each containing three conserved sequence blocks (CSB). Based on the sequence around CSB 3 from Hart 1, PCR primers were designed to allow specific amplification of Phytomonas minicircles. This primer pair demonstrated specificity for at least six groups of plant trypanosomatids and did not amplify from insect trypanosomatids. The PCR results were consistent with a two-domain structure for other plant trypanosomatids.

Requirements and design structure for Surya Satellite-1

NASA Astrophysics Data System (ADS)

Steven, H.; Huzain, M. F.

2018-05-01

Currently, there are various references on the manufacture of nanosatellite specifications weighing 1KG - 10KG.The Surya Satellite-1 is the first nanosatellite made by universities in Indonesia. The Surya Satellite-1 team gets a launch offer from Japan Aerospace Exploration Agency (JAXA) and, all the nanosatellites manufacturer racers at ICD (Interface Control Document) obtained from JAXA. The formation of the Satellite-1 Surya framework is also based on the provisions of JAXA. The various specifications and requirements specified by the JAXA space agency consisting of specific specifications such as the mass of nanosatellite 1U (10cm x 10cm x 11.65cm) size of at least 0.13KG and a maximum of 1.33KG, with the determination of a gravity point not exceeding 2 cm from the nanosatellite geometry center point. In the case of preventing solar radiation in space, there is a requirement that the structure of satellite structures on hard black anodization should be more than 10 meters in the surface of the satellite structure. In terms of detail, the satellite structure is a black hard anodized aluminum after its manufacturing process derived from the MIL-A-8625 document, type 3.

Safety envelope for load tolerance of structural element design based on multi-stage testing

DOE PAGES

Park, Chanyoung; Kim, Nam H.

2016-09-06

Structural elements, such as stiffened panels and lap joints, are basic components of aircraft structures. For aircraft structural design, designers select predesigned elements satisfying the design load requirement based on their load-carrying capabilities. Therefore, estimation of safety envelope of structural elements for load tolerances would be a good investment for design purpose. In this article, a method of estimating safety envelope is presented using probabilistic classification, which can estimate a specific level of failure probability under both aleatory and epistemic uncertainties. An important contribution of this article is that the calculation uncertainty is reflected in building a safety envelope usingmore » Gaussian process, and the effect of element test data on reducing the calculation uncertainty is incorporated by updating the Gaussian process model with the element test data. It is shown that even one element test can significantly reduce the calculation uncertainty due to lacking knowledge of actual physics, so that conservativeness in a safety envelope is significantly reduced. The proposed approach was demonstrated with a cantilever beam example, which represents a structural element. The example shows that calculation uncertainty provides about 93% conservativeness against the uncertainty due to a few element tests. As a result, it is shown that even a single element test can increase the load tolerance modeled with the safety envelope by 20%.« less

Structural analysis of color video camera installation on tank 241AW101 (2 Volumes)

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

Strehlow, J.P.

1994-08-24

A video camera is planned to be installed on the radioactive storage tank 241AW101 at the DOE` s Hanford Site in Richland, Washington. The camera will occupy the 20 inch port of the Multiport Flange riser which is to be installed on riser 5B of the 241AW101 (3,5,10). The objective of the project reported herein was to perform a seismic analysis and evaluation of the structural components of the camera for a postulated Design Basis Earthquake (DBE) per the reference Structural Design Specification (SDS) document (6). The detail of supporting engineering calculations is documented in URS/Blume Calculation No. 66481-01-CA-03 (1).

Optimal design of structures with multiple design variables per group and multiple loading conditions on the personal computer

NASA Technical Reports Server (NTRS)

Nguyen, D. T.; Rogers, J. L., Jr.

1986-01-01

A finite element based programming system for minimum weight design of a truss-type structure subjected to displacement, stress, and lower and upper bounds on design variables is presented. The programming system consists of a number of independent processors, each performing a specific task. These processors, however, are interfaced through a well-organized data base, thus making the tasks of modifying, updating, or expanding the programming system much easier in a friendly environment provided by many inexpensive personal computers. The proposed software can be viewed as an important step in achieving a 'dummy' finite element for optimization. The programming system has been implemented on both large and small computers (such as VAX, CYBER, IBM-PC, and APPLE) although the focus is on the latter. Examples are presented to demonstrate the capabilities of the code. The present programming system can be used stand-alone or as part of the multilevel decomposition procedure to obtain optimum design for very large scale structural systems. Furthermore, other related research areas such as developing optimization algorithms (or in the larger level: a structural synthesis program) for future trends in using parallel computers may also benefit from this study.

[Near infrared spectroscopy system structure with MOEMS scanning mirror array].

PubMed

Luo, Biao; Wen, Zhi-Yu; Wen, Zhong-Quan; Chen, Li; Qian, Rong-Rong

2011-11-01

A method which uses MOEMS mirror array optical structure to reduce the high cost of infrared spectrometer is given in the present paper. This method resolved the problem that MOEMS mirror array can not be used in simple infrared spectrometer because the problem of imaging irregularity in infrared spectroscopy and a new structure for spectral imaging was designed. According to the requirements of imaging spot, this method used optical design software ZEMAX and standard-specific aberrations of the optimization algorithm, designed and optimized the optical structure. It works from 900 to 1 400 nm. The results of design analysis showed that with the light source slit width of 50 microm, the spectrophotometric system is superior to the theoretical resolution of 6 nm, and the size of the available spot is 0.042 mm x 0.08 mm. Verification examples show that the design meets the requirements of the imaging regularity, and can be used for MOEMS mirror reflectance scan. And it was also verified that the use of a new MOEMS mirror array spectrometer model is feasible. Finally, analyze the relationship between the location of the detector and the maximum deflection angle of micro-mirror was analyzed.

A Probabilistic Design Method Applied to Smart Composite Structures

NASA Technical Reports Server (NTRS)

Shiao, Michael C.; Chamis, Christos C.

1995-01-01

A probabilistic design method is described and demonstrated using a smart composite wing. Probabilistic structural design incorporates naturally occurring uncertainties including those in constituent (fiber/matrix) material properties, fabrication variables, structure geometry and control-related parameters. Probabilistic sensitivity factors are computed to identify those parameters that have a great influence on a specific structural reliability. Two performance criteria are used to demonstrate this design methodology. The first criterion requires that the actuated angle at the wing tip be bounded by upper and lower limits at a specified reliability. The second criterion requires that the probability of ply damage due to random impact load be smaller than an assigned value. When the relationship between reliability improvement and the sensitivity factors is assessed, the results show that a reduction in the scatter of the random variable with the largest sensitivity factor (absolute value) provides the lowest failure probability. An increase in the mean of the random variable with a negative sensitivity factor will reduce the failure probability. Therefore, the design can be improved by controlling or selecting distribution parameters associated with random variables. This can be implemented during the manufacturing process to obtain maximum benefit with minimum alterations.

Drilling and completion specifications for CA series multilevel piezometers

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

Clawson, T.S.

1986-08-01

CX Series multilevel piezometer boreholes will provide information on hydraulic heads in the Rosalia, Sentinel Gap, Ginkgo, Rocky Coulee, Cohassett, Birkett, and Umtanum flow tops. The borehole sites will be located adjacent to the reference repository location. In addition, information from the boreholes will provide input data used to determine horizontal and vertical flow rates, and identify possible geologic structures. This specification includes details for drilling, piezometer design, hydrologic testing, and hydrochemical sampling of the boreholes. It includes drilling requirements, design, and installation procedures for the series piezometer nests, intervals selected for head monitoring and schedules for drilling and piezometermore » installation. Specific drilling and piezometer installation specifications for boreholes DC-24CX and DC-25CX are also included. 27 refs., 5 figs., 3 tabs.« less

Some design constraints required for the assembly of software components: The incorporation of atomic abstract types into generically structured abstract types

NASA Technical Reports Server (NTRS)

Johnson, Charles S.

1986-01-01

It is nearly axiomatic, that to take the greatest advantage of the useful features available in a development system, and to avoid the negative interactions of those features, requires the exercise of a design methodology which constrains their use. A major design support feature of the Ada language is abstraction: for data, functions processes, resources, and system elements in general. Atomic abstract types can be created in packages defining those private types and all of the overloaded operators, functions, and hidden data required for their use in an application. Generically structured abstract types can be created in generic packages defining those structured private types, as buildups from the user-defined data types which are input as parameters. A study is made of the design constraints required for software incorporating either atomic or generically structured abstract types, if the integration of software components based on them is to be subsequently performed. The impact of these techniques on the reusability of software and the creation of project-specific software support environments is also discussed.

A modified approach to controller partitioning

NASA Technical Reports Server (NTRS)

Garg, Sanjay; Veillette, Robert J.

1993-01-01

The idea of computing a decentralized control law for the integrated flight/propulsion control of an aircraft by partitioning a given centralized controller is investigated. An existing controller partitioning methodology is described, and a modified approach is proposed with the objective of simplifying the associated controller approximation problem. Under the existing approach, the decentralized control structure is a variable in the partitioning process; by contrast, the modified approach assumes that the structure is fixed a priori. Hence, the centralized controller design may take the decentralized control structure into account. Specifically, the centralized controller may be designed to include all the same inputs and outputs as the decentralized controller; then, the two controllers may be compared directly, simplifying the partitioning process considerably. Following the modified approach, a centralized controller is designed for an example aircraft mode. The design includes all the inputs and outputs to be used in a specified decentralized control structure. However, it is shown that the resulting centralized controller is not well suited for approximation by a decentralized controller of the given structure. The results indicate that it is not practical in general to cast the controller partitioning problem as a direct controller approximation problem.

TokenPasser: A petri net specification tool. Thesis

NASA Technical Reports Server (NTRS)

Mittmann, Michael

1991-01-01

In computer program design it is essential to know the effectiveness of different design options in improving performance, and dependability. This paper provides a description of a CAD tool for distributed hierarchical Petri nets. After a brief review of Petri nets, Petri net languages, and Petri net transducers, and descriptions of several current Petri net tools, the specifications and design of the TokenPasser tool are presented. TokenPasser is a tool to allow design of distributed hierarchical systems based on Petri nets. A case study for an intelligent robotic system is conducted, a coordination structure with one dispatcher controlling three coordinators is built to model a proposed robotic assembly system. The system is implemented using TokenPasser, and the results are analyzed to allow judgment of the tool.

Structures of Human DPP7 Reveal the Molecular Basis of Specific Inhibition and the Architectural Diversity of Proline-Specific Peptidases

PubMed Central

Dong, Aiping; Seitova, Almagul; Crombett, Lissete; Shewchuk, Lisa M.; Hassell, Annie M.; Sweitzer, Sharon M.; Sweitzer, Thomas D.; McDevitt, Patrick J.; Johanson, Kyung O.; Kennedy-Wilson, Karen M.; Cossar, Doug; Bochkarev, Alexey; Gruber, Karl; Dhe-Paganon, Sirano

2012-01-01

Proline-specific dipeptidyl peptidases (DPPs) are emerging targets for drug development. DPP4 inhibitors are approved in many countries, and other dipeptidyl peptidases are often referred to as DPP4 activity- and/or structure-homologues (DASH). Members of the DASH family have overlapping substrate specificities, and, even though they share low sequence identity, therapeutic or clinical cross-reactivity is a concern. Here, we report the structure of human DPP7 and its complex with a selective inhibitor Dab-Pip (L-2,4-diaminobutyryl-piperidinamide) and compare it with that of DPP4. Both enzymes share a common catalytic domain (α/β-hydrolase). The catalytic pocket is located in the interior of DPP7, deep inside the cleft between the two domains. Substrates might access the active site via a narrow tunnel. The DPP7 catalytic triad is completely conserved and comprises Ser162, Asp418 and His443 (corresponding to Ser630, Asp708 and His740 in DPP4), while other residues lining the catalytic pockets differ considerably. The “specificity domains” are structurally also completely different exhibiting a β-propeller fold in DPP4 compared to a rare, completely helical fold in DPP7. Comparing the structures of DPP7 and DPP4 allows the design of specific inhibitors and thus the development of less cross-reactive drugs. Furthermore, the reported DPP7 structures shed some light onto the evolutionary relationship of prolyl-specific peptidases through the analysis of the architectural organization of their domains. PMID:22952628

Designing of Timber Bolt Connection Subjected To Double Unequal Shears

NASA Astrophysics Data System (ADS)

Musilek, Josef; Plachy, Jan

2017-10-01

The paper deals with load-carrying capacity of bolted connections subjected to unequal double shear with thin plates as outer members and inner timber member. This type of connection is usually widespread and in building support structures made of wood is commonly used. This may occur for example in skeletal structures which contain structural elements based on wood, but also for smaller wooden buildings. Specifically, this type of connection can be found in ceiling structures in the joint joists and beams. If one joist greater margin than the second, bringing the load on the side of the joists of a larger span greater loads than on the side with a smaller span joist. Structure engineer, who is designing such a connection, must use for the design of the connection design procedures and formulas from which he or she calculates the design resistance in order to carry out further assessment of the reliability of the connection in the ultimate limit state. The load-carrying capacity of this connections type can be calculated at present according to Johansen’s equations, which are also contained in present European standard for the design timber structures -Eurocode 5. These Johansen’s equations assume that the loads which act on the outer plates are equal. For this reason, the structure engineer is often forced to use formulas intended for the timber bolt connection subjected to double equal shear and he or she must find ways how to use them although the formulas are not suitable. This paper deals with the case, when the loads acting on the outer plates are unequal.