716
716
Nov 13, 2012
11/12
by
Pat Morin
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Topics: data structures, computer-science, structures, computer science, data
63,024
63K
Oct 31, 2013
10/13
by
MIT OpenCourseWare
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View the complete course: http://ocw.mit.edu/6-851S12 Instructor: Erik Demaine Videos of 6.851 Lectures Spring 2012 License: Creative Commons BY-NC-SA More information at http://ocw.mit.edu/terms More courses at http://ocw.mit.edu
Topic: advanced data structures
Microcellular nanocomposite foams and sandwich structures have been created to have excellent electrical conductivity and radiation-resistant properties using a new method that does not involve or release any toxicity. The nanocomposite structures have been scaled up in size to 12 X 12 in. (30 X 30 cm) for components fabrication. These sandwich materials were fabricated mainly from PE, CNF, and carbon fibers. Test results indicate that they have very good compression and...
Topics: NASA Technical Reports Server (NTRS), NANOCOMPOSITES, FOAMS, SANDWICH STRUCTURES, SPACECRAFT...
A method of assembling an inflatable shell of a structure comprises folding a plurality of shell sections about a set of fold lines and integrating the plurality of shell sections together with one another to form the shell. In another embodiment, an inflatable shell comprises a plurality of shell sections, each shell section having two pairs of fold lines for folding into stowage comprising a first gore section having a plurality of first gore panels layered and collectively folded about at a...
Topics: NASA Technical Reports Server (NTRS), FABRICATION, INFLATABLE STRUCTURES, PANELS, SHELLS...
84
84
Dec 28, 2013
12/13
by
Russell Bagdoo
texts
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The theory of Relation is based on the existence of two structures going in opposite directions and, throughout the cosmological time, on a real conversion of the negative energy of the structure of expansion into the positive energy of the structure of condensation. The theory explores the situation of the quantum vacuum which contains a minimum energy at the surface of an ocean of negative energy, fueling the ordinary positive matter above. Under the principle of Compensation, the energy...
Topics: two structures, negative energy, principle of Compensation, vacuum, irreversible time
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87
Dec 28, 2013
12/13
by
Russell Bagdoo
texts
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La théorie de la Relation est basée sur l’existence de deux structures qui vont en directions opposées et sur une transformation réelle, tout au long du temps cosmologique, de l’énergie négative de la structure de l’expansion en énergie positive de la structure de la condensation, en vertu du principe de Compensation. Les fluctuations d’énergie du vide se matérialisent spontanément non seulement en nombreux couples virtuels mais aussi réels. Deux sortes de masse et énergie...
Topics: deux structures, l’énergie négative, principe de Compensation, vacuum, temps irréversible
1,644
1.6K
Nov 13, 2012
11/12
by
Pat Morin
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Topics: data structures, computer-science, java, computer science, data
Membrane dominated space structures are lightweight and package efficiently for launch; however, they must be expanded (deployed) in-orbit to achieve the desired geometry. These expandable structural systems include solar sails, solar power arrays, antennas, and numerous other large aperture devices that are used to collect, reflect and/or transmit electromagnetic radiation. In this work, an integrated approach to development of thin-film damage tolerant membranes is explored using advanced...
Topics: NASA Technical Reports Server (NTRS), EXPANDABLE STRUCTURES, LARGE SPACE STRUCTURES, MEMBRANE...
NASA's Advanced Composites Technologies (ACT) project evaluated several composite construction options for the Ares V Interstage to support the Constellation Program's goal of reducing the mass of vehicle dry structures. In Phase 1 of the project, eight candidate construction concepts were evaluated for the Ares V Interstage design. Trade studies were performed using finite element analyses to determine weight estimates for the construction concepts. An evaluation process was then used to down...
Topics: NASA Technical Reports Server (NTRS), COMPOSITE STRUCTURES, HONEYCOMB STRUCTURES, ARES 5 CARGO...
This paper provides a summary of the structural architecture assessments conducted and a recommendation for an affordable high performance composite structural concept to use on the next generation heavy-lift launch vehicle, the Space Launch System (SLS). The Structural Concepts Element of the Advanced Composites Technology (ACT) project and its follow on the Lightweight Spacecraft Structures and Materials (LSSM) project was tasked with evaluating a number of composite construction technologies...
Topics: NASA Technical Reports Server (NTRS), HEAVY LIFT LAUNCH VEHICLES, SPACECRAFT STRUCTURES, STRUCTURAL...
An inflatable, rigidizable shelter system was developed based on Rigi dization on Command (ROC) technology incorporating not only the requ ired low-stowage volume and lightweight character achieved from an i nflatable/rigidizable system, but also a self-healing foam system inc orporated between the rigidizable layers of the final structure to m inimize the damage caused by any punctures to the structure.
Topics: NASA Technical Reports Server (NTRS), FOAMS, SHELTERS, INFLATABLE STRUCTURES, RIGID STRUCTURES,...
Two manufacturing demonstration panels (1/16th-arc-segments of 10 m diameter cylinder) were fabricated under the composites part of the Lightweight Space Structures and Materials program. Both panels were of sandwich construction with aluminum core and 8-ply quasi-isotropic graphite/epoxy facesheets. One of the panels was constructed with in-autoclave curable unidirectional prepreg (IM7/977-3) and the second with out-of-autoclave unidirectional prepreg (T40-800B/5320-1). Following NDE...
Topics: NASA Technical Reports Server (NTRS), AUTOCLAVES, CHARACTERIZATION, COMPOSITE STRUCTURES,...
The NASA Human Space Flight program is interested in projects where humans, beyond low-Earth orbit (LEO), can make an important and unique contribution that cannot be reasonably accomplished purely by robotic means, and is commensurate with the effort and cost associated with human spaceflight. Robotic space telescope missions have been conceived and launched as completed assemblies (e.g., Hubble) or as jack-in-the-box one-time deployments (e.g., James Webb). If it were possible to assemble...
Topics: NASA Technical Reports Server (NTRS), HANGARS, INTERNATIONAL SPACE STATION, LARGE SPACE STRUCTURES,...
The telescope of the James Webb Space Telescope (JWST) is an f/20, three mirror anastigmat design, passively cooled (40K) in an L2 orbit. The design provides diffraction limited performance (Strehl > or = 0.8) at .=2 m. To fit within the launch vehicle envelope (Arianne V), the 6.6 meter primary mirror and the secondary mirror support structure are folded for launch, then deployed and aligned in space. The primary mirror is composed of 18 individual, 1.3 meter (flat flat) hexagonal...
Topics: NASA Technical Reports Server (NTRS), JAMES WEBB SPACE TELESCOPE, MIRRORS, FABRICATION, COMPOSITE...
Honeycomb silicon carbide composite mirrors are made from a carbon fiber preform that is molded into a honeycomb shape using a rigid mold. The carbon fiber honeycomb is densified by using polymer infiltration pyrolysis, or through a reaction with liquid silicon. A chemical vapor deposit, or chemical vapor composite (CVC), process is used to deposit a polishable silicon or silicon carbide cladding on the honeycomb structure. Alternatively, the cladding may be replaced by a freestanding,...
Topics: NASA Technical Reports Server (NTRS), CARBON FIBERS, HONEYCOMB STRUCTURES, MANUFACTURING, MIRRORS,...
Fatigue life prediction capabilities have been incorporated into the HyperSizer Composite Analysis and Structural Sizing Software. The fatigue damage model is introduced at the fiber/matrix constituent scale through HyperSizer s coupling with NASA s MAC/GMC micromechanics software. This enables prediction of the micro scale damage progression throughout stiffened and sandwich panels as a function of cycles leading ultimately to simulated panel failure. The fatigue model implementation uses a...
Topics: NASA Technical Reports Server (NTRS), COMPOSITE STRUCTURES, FATIGUE (MATERIALS), MICROMECHANICS,...
Efficient closed-form methods for predicting the facesheet wrinkling failure mode in sandwich panels are assessed. Comparisons were made with finite element model predictions for facesheet wrinkling, and a validated closed-form method was implemented in the HyperSizer structure sizing software.
Topics: NASA Technical Reports Server (NTRS), HONEYCOMB STRUCTURES, SANDWICH STRUCTURES, FAILURE MODES,...
In support of NASA s Habitat Demonstration Unit - Deep Space Habitat Prototype, a number of evolved structural sections were designed, fabricated, analyzed and installed in the 5 meter diameter prototype. The hardware consisted of three principal structural sections, and included the development of novel fastener insert concepts. The articles developed consisted of: 1) 1/8th of the primary flooring section, 2) an inner radius floor beam support which interfaced with, and supported (1), 3) two...
Topics: NASA Technical Reports Server (NTRS), HABITATS, DESIGN ANALYSIS, STRUCTURAL DESIGN, HONEYCOMB...
Based on extensive access to over 50 operating underground facilities (UGFs) where fire protection and life safety capabilities were examined as a part of comprehensive survivability assessments, we conclude that existing fire protection codes used in all examined country's UGFs are generally inadequate to serve a large class of special purpose underground structures. Recommended practices to mitigate those inadequacies are discussed in the context of UGF operational constraints and threat...
Topics: DTIC Archive, RAYTHEON UTD INC SPRINGFIELD VA, *FIRE PROTECTION, *SAFETY, *UNDERGROUND FACILITIES,...
A document describes a new way to integrate thermal protection materials on external surfaces of vehicles that experience the severe heating environments of atmospheric entry from space. Cured blocks of thermal protection materials are bonded into a compatible, large-cell honeycomb matrix that can be applied on the external surfaces of the vehicles. The honeycomb matrix cell size, and corresponding thermal protection material block size, is envisioned to be between 1 and 4 in. (.2.5 and 10 cm)...
Topics: NASA Technical Reports Server (NTRS), HEAT SHIELDING, HONEYCOMB STRUCTURES, THERMAL PROTECTION,...
Here is a brief list of materials that NASA will not be using to construct spacecraft: wood, adobe, fiberglass, bone. While it might be obvious why these materials would not make for safe space travel, they do share a common characteristic with materials that may well be the future foundation of spacecraft design: They all are composites. Formed of two or more unlike materials - such as cellulose and lignin in the case of wood, or glass fibers and plastic resin in the case of...
Topics: NASA Technical Reports Server (NTRS), AEROSPACE ENGINEERING, AIRCRAFT STRUCTURES, COMPOSITE...
Studies of the human microbiome have revealed that even healthy individuals differ remarkably in the microbes that occupy habitats such as the gut, skin and vagina. Much of this diversity remains unexplained, although diet, environment, host genetics and early microbial exposure have all been implicated. Accordingly, to characterize the ecology of human-associated microbial communities, the Human Microbiome Project has analysed the largest cohort and set of distinct, clinically relevant body...
Topics: DTIC Archive, HARVARD SCHOOL OF PUBLIC HEALTH BOSTON MA, *FUNCTIONS, *GENES, *HUMANS, *STRUCTURES,...
1
1.0
Nov 29, 2019
11/19
by
Gugliotta, Guy
texts
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viii, 486 p. : 24 cm
Topics: United States Capitol (Washington, D.C.) -- History, Washington (D.C.) -- Buildings, structures,...
Using data compiled by the National Weather Service Ocean Prediction Center, a hurricane force extratropical cyclone climatology is created for three cold seasons. Using the criteria of Sanders and Gyakum (1980), it is found that 75% of the 259 storms explosively deepened. The frequency maximum in the Atlantic basin is located to the southeast of Greenland. In the Pacific, two maxima to the east of Japan are identified. These results are in good agreement with previous studies, despite...
Topics: DTIC Archive, NAVAL POSTGRADUATE SCHOOL MONTEREY CA, *CLIMATOLOGY, ANOMALIES, COMPOSITE STRUCTURES,...
The most significant finding during this research period was a clear theoretical foundation for partial differential equation (PDE)-based tractography that inherently includes constraints within the formalism. This foundation has enabled us to make rational choices in developing an algorithm capable of mapping whole-brain networks of axonal connectivity. The algorithm satisfies two necessary conditions: 1) it can identify connections invisible to standard streamline throughout the entire brain...
Topics: DTIC Archive, CLEVELAND CLINIC FOUNDATION OH, *TRAUMATIC BRAIN INJURIES, ELECTROPHYSIOLOGY,...
14
14
Oct 31, 2019
10/19
by
Guard, Richard (Film editor)
texts
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192 pages : 21 cm
Topics: Buildings, London (England) -- History, London (England) -- Buildings, structures, etc, England --...
The purpose of the present study is to examine cognitive fictions of classroom teachers about the values they possess. The study was designed with a phenomenological pattern, which is a qualitative research pattern. It was conducted with 20 classroom teachers who work in the central Yakutiye district of Erzurum who were chosen via criterion sampling method which is a purposeful sampling method. Data were collected with the repertory grid form based on the structured interview technique. Content...
Topics: ERIC Archive, Foreign Countries, Values, Teachers, Cognitive Structures, Structured Interviews,...
The Sensor Research Lab at the Naval Postgraduate School is developing a real-time THz imaging camera. Vital to its design is the metamaterial absorbing layer (metafilm) within each pixel that allows for THz absorption. While there are numerous applications in the THz region, sensors and sources for THz energy have much room for improvement. The use of metamaterial technology for the purpose of a THz sensor has the potential to reduce costs while greatly improving sensitivity performance. The...
Topics: DTIC Archive, NAVAL POSTGRADUATE SCHOOL MONTEREY CA, *METAMATERIALS, ELECTROMAGNETIC RADIATION,...
This dissertation introduces Pikse, a novel methodology for more effective and efficient checking of code conformance to specifications using parallel and incremental techniques, describes a prototype implementation that embodies the methodology, and presents experiments that demonstrate its efficacy. Pikse has at its foundation a well-studied approach - systematic constraint-driven analysis - that has two common forms: (1) constraint-based testing - where logical constraints that define...
Topics: DTIC Archive, TEXAS UNIV AT AUSTIN, *SYSTEMS ANALYSIS, COMPUTER PROGRAMS, EFFICIENCY,...
The Material Logic program aims to create novel materials that exhibit high stiffness and high damping. The joint Texas A&M University (Texas Engineering Experiment Station or TEES)/The Aerospace Corporation (AERO) effort seeks to develop a new composite material by exploiting negative-stiffness, positive-stiffness, and damping elements to form a novel material system. Overall success is defined as developing a material that can achieve a 1.0 damping coefficient with a 100 GPa elastic...
Topics: DTIC Archive, TEXAS ENGINEERING EXPERIMENT STATION COLLEGE STATION, *COMPOSITE MATERIALS, COMPOSITE...
Topics: DTIC Archive, MICHIGAN UNIV ANN ARBOR, *SHAPE MEMORY ALLOYS, HONEYCOMB STRUCTURES, RESPONSE,...
New theory is presented for evolving systems, which are autonomously controlled subsystems that self-assemble into a new evolved system with a higher purpose. Evolving systems of aerospace structures often require additional control when assembling to maintain stability during the entire evolution process. This is the concept of Adaptive Key Component Control that operates through one specific component to maintain stability during the evolution. In addition, this control must often overcome...
Topics: NASA Technical Reports Server (NTRS), ADAPTIVE CONTROL, SELF ASSEMBLY, AIRCRAFT STRUCTURES,...
This paper reviews the theoretical foundation and computational mechanics aspects of the recently developed shear-deformation theory, called the Refined Zigzag Theory (RZT). The theory is based on a multi-scale formalism in which an equivalent single-layer plate theory is refined with a robust set of zigzag local layer displacements that are free of the usual deficiencies found in common plate theories with zigzag kinematics. In the RZT, first-order shear-deformation plate theory is used as the...
Topics: NASA Technical Reports Server (NTRS), COMPOSITE STRUCTURES, LAMINATES, SANDWICH STRUCTURES, SHEAR...
This paper reviews the theoretical foundation and computational mechanics aspects of the recently developed shear-deformation theory, called the Refined Zigzag Theory (RZT). The theory is based on a multi-scale formalism in which an equivalent single-layer plate theory is refined with a robust set of zigzag local layer displacements that are free of the usual deficiencies found in common plate theories with zigzag kinematics. In the RZT, first-order shear-deformation plate theory is used as the...
Topics: NASA Technical Reports Server (NTRS), LAMINATES, COMPOSITE STRUCTURES, BEAMS (SUPPORTS), SANDWICH...
This project is concerned with a new class of light-weight, hierarchical engineered material systems designed to mitigate effects due to high intensity short duration loads, such as blast. A fundamental research program that combines elements of experiments, analysis and the conception of novel numerical tools to tackle several challenging issues are described. The proposed work will be focused on engineered materials and structures that are exposed to loads of high intensity and short...
Topics: DTIC Archive, MICHIGAN UNIV ANN ARBOR DEPT OF AEROSPACE ENGINEERING, *COMPOSITE STRUCTURES, BLAST...
A two part research study has been completed on the topic of compression after impact (CAI) of thin facesheet honeycomb core sandwich panels. The research has focused on both experiments and analysis in an effort to establish and validate a new understanding of the damage tolerance of these materials. Part one, the subject of the current paper, is focused on the experimental testing. Of interest are sandwich panels, with aerospace applications, which consist of very thin, woven S2-fiberglass...
Topics: NASA Technical Reports Server (NTRS), SANDWICH STRUCTURES, HONEYCOMB STRUCTURES, FAILURE MODES,...
Design, analysis, and sizing methods for two novel structural panel concepts have been developed and incorporated into the HyperSizer Structural Sizing Software. Reinforced Core Sandwich (RCS) panels consist of a foam core with reinforcing composite webs connecting composite facesheets. Boeing s Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) panels use a pultruded unidirectional composite rod to provide axial stiffness along with integrated transverse frames and stitching. Both of...
Topics: NASA Technical Reports Server (NTRS), SANDWICH STRUCTURES, HONEYCOMB STRUCTURES, COMPOSITE...
Even though membrane proteins that mediate transport of ions and small molecules across cell walls are among the largest and least understood biopolymers in contemporary cells, it is still possible to shed light on their origins and early evolution. The central observation is that transmembrane portions of most ion channels are simply bundles of -helices. By combining results of experimental and computer simulation studies on synthetic models and natural channels, mostly of non-genomic origin,...
Topics: NASA Technical Reports Server (NTRS), MEMBRANES, PROTEINS, CELLS (BIOLOGY), AMINO ACIDS,...
A document describes a reliable, lightweight micrometeoroid/orbital debris (MMOD) detection system that can be located at strategic positions of "high consequence" to provide real-time warning of a penetration, its location, and the extent of the damage to a spacecraft. The concept is to employ fiber-optic sensors to detect impact damage and penetration of spacecraft structures. The fibers are non-electrical, employ light waves, and are immune to electromagnetic interference. The...
Topics: NASA Technical Reports Server (NTRS), MICROMETEOROIDS, ELECTROMAGNETIC INTERFERENCE, IMPACT DAMAGE,...
The present work is related to the development and application of progressive damage modeling techniques to bonded joint technology. The joint designs studied in this work include a conventional composite splice joint and a NASA-patented durable redundant joint. Both designs involve honeycomb sandwich structures with carbon/epoxy facesheets joined using adhesively bonded doublers.Progressive damage modeling allows for the prediction of the initiation and evolution of damage within a structure....
Topics: NASA Technical Reports Server (NTRS), EPOXY MATRIX COMPOSITES, DELAMINATING, DAMAGE ASSESSMENT,...
Globally, potential adversaries are building ever more complex, stronger, and deeper fortifications which are largely immune to the current U.S. weapons inventory. Advanced construction and design techniques coupled with technological improvements in mining have created a perfect storm of ultra-strong fortifications located at depths unreachable to all but the most distinctive and matchless weapon systems. A new domain is emerging that must be appreciated for its dynamic effect on policy,...
Topics: DTIC Archive, ARMY COMMAND AND GENERAL STAFF COLL FORT LEAVENWORTH KS, *COUNTERMEASURES, *DEEP...
This report, concluding a one-year NIAC Phase I study, describes a new structural and mechanical technique aimed at reducing the mass and increasing the deployed-to-stowed length and volume ratios of spacecraft systems. This technique uses the magnetic fields generated by electrical current passing through coils of high-temperature superconductors (HTSs) to support spacecraft structures and deploy them to operational configurations from their stowed positions inside a launch vehicle fairing.
Topics: NASA Technical Reports Server (NTRS), HIGH TEMPERATURE SUPERCONDUCTORS, SUPERCONDUCTORS...
Composites are rapidly replacing metals in structural applications due to their ability to outperform metals at significant weight savings. This has resulted in the need for monitoring techniques to prevent catastrophic failures. Crosslink is developing a real-time, light-weight strain/damage sensor system that can be either embedded in or superficially bonded at strategic locations to monitor structural integrity. These sensors utilize inherently conducting polymer (ICP) films. ICP-based...
Topics: DTIC Archive, LUMIMOVE INC FENTON MO DBA CROSSLINK, *CATASTROPHIC CONDITIONS, *COMPOSITE...
Due to increasing complexity, multi-material incompatibilities, and size constraints of electronics, no single monolithic technology can adequately realize the full spectrum of Army-relevant applications. The integration of a wide range of devices, each fabricated in different technologies and performing a well-defined task, would enable the construction of high performance systems. We use a custom microfabrication process flow to align dies within a silicon template wafer to obtain a common...
Topics: DTIC Archive, ARMY RESEARCH LAB ADELPHI MD SENSORS AND ELECTRON DEVICES DIRECTORATE, *ELECTRONICS,...
Foundational research examining aerodynamic interactions of laminar/transitional/turbulent flows with structures, rigid or flexible, stationary or moving. Fundamental understanding is used to develop integrated control approaches to intelligently modify the flow interaction to some advantage.
Topics: DTIC Archive, AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH, *AERODYNAMICS, AIR FORCE RESEARCH,...
This report documents the investigations and development of low noise interband-cascade infrared photodetectors (ICIPs) at the University of Oklahoma (in collaborations with others) for a period of time from May 2009 to Nov. 2011. ICIPs, composed of discrete superlattice (SL) absorbers, are demonstrated at temperatures up to 350K in the mid-infrared spectral region. The peak responsivity exceeds 200 mA/W, suggesting a significantly enhanced quantum efficiency of the SL absorbers. We showed that...
Topics: DTIC Archive, OKLAHOMA UNIV NORMAN SCHOOL OF ELECTRICAL AND COMPUTER ENGINEERING, *PHOTODETECTORS,...
This brochure contains information on the Department of Defense (DoD) Standard Family of Tactical Shelters. The standard rigid wall, soft wall, and hybrid shelters shown in this brochure have been approved by the Joint Committee on Tactical Shelters (JOCOTAS) for Department of Defense (DoD) use.
Topics: DTIC Archive, ARMY NATICK SOLDIER RESEARCH DEVELOPMENT AND ENGINEERING CENTER MA, *SHELTERS,...
Topics: DTIC Archive, MICHIGAN UNIV ANN ARBOR, *SHAPE MEMORY ALLOYS, ALUMINUM, BRAZED JOINTS, FABRICATION,...
As design has moved from strength based to performance based, there has been an effort to relate building response to damage. Because decision-makers typically consider human lives, property damage and cost, setting performance requirements in terms of the damage that a building is likely to sustain over time and its associated cost is more relevant to them. The Pacific Earthquake Engineering Research Center (PEER) has developed a computationally expensive methodology for estimating cumulative...
Topics: DTIC Archive, MASSACHUSETTS INST OF TECH CAMBRIDGE, *EARTHQUAKE ENGINEERING, BUILDINGS, DAMAGE,...
COMPSCI 61B LEC 001 Fa12 Data Structures
Topics: UC Berkeley, Berkeley, Cal, webcast.berkeley, iTunes U, Engineering, Education, course, Computer...
